Cancer Prevalence among a Cross-sectional Survey of Female Orthopedic, Urology, and Plastic Surgeons in the United States WOMENS HEALTH ISSUES 2015; 25 (5): 476-481
Exposure to ionizing radiation from fluoroscopy performed during surgery, although low and within established limits, remains a health concern among surgeons. Estimates of breast cancer prevalence among women across surgery specialties with different patterns of fluoroscopy use are needed to evaluate this concern.Female U.S. surgeons in urology, plastics, and orthopedics were identified using national directories and mailed surveys to collect information on occupational and medical history, including cancer diagnoses. Standardized prevalence ratios (SPRs) and 95% CIs were calculated by dividing the observed number of cancers among female surgeons in each specialty by the expected number, based on the gender-specific, age-specific, and race-specific cancer prevalence statistics in the general U.S.Standard fluoroscopy use more than once per week was common among urologists (54%) and orthopedists (37%); the same frequency of mini fluoroscopy use was only common among orthopedics (31%) and hardly ever used by urologists. Plastic surgeons reported very infrequent use of any fluoroscopy. For orthopedic surgeons, a significantly greater than expected prevalence of any cancer (SPR,1.85; 95% CI, 1.19-2.76) and breast cancer (SPR,2.90; 95% CI, 1.66-4.71) were observed. There was no difference between the observed and expected prevalence of any cancer or breast cancer for urology or plastics.Using the first available cancer prevalence data comparing female surgeons across three specialties, we report that orthopedic surgeons have a greater than expected prevalence of cancer that may or may not be owing to occupational exposure to ionizing radiation.
View details for DOI 10.1016/j.whi.2015.05.005
View details for Web of Science ID 000361060400009
Prevalence of Cancer in Female Plastic Surgeons in the United States Womens Health Issues 2015; 25 (5): 229-32
Caries Management By Risk Assessment in a Cleft and Craniofacial Center JOURNAL OF CRANIOFACIAL SURGERY 2014; 25 (6): E529-E536
Management of Frontal Sinus Fractures: Treatment Modality Changes at a Level I Trauma Center JOURNAL OF CRANIOFACIAL SURGERY 2014; 25 (6): 2038-2042
Management of frontal sinus fractures: treatment modality changes at a level I trauma center. journal of craniofacial surgery 2014; 25 (6): 2038-2042
The optimal management of frontal sinus fractures remains controversial, and previously accepted indications for surgical intervention are being challenged. The goals of this study were to determine how frontal sinus fracture management has changed at a single institution across multiple disciplines and to evaluate the long-term outcomes of operative and nonoperative treatment modalities.Patients treated for a frontal sinus fracture at Stanford Hospital and Clinics between June 1998 and June 2009 were included in the study. Inpatient records, clinic notes, operative reports, and radiographic studies were reviewed. The patients were invited for a follow-up clinic visit, physical examination, and focused sinus computed tomography. For a period of 11 years, 124 patients were treated for a frontal sinus fracture by physicians from 3 surgical subspecialties: otolaryngology, plastic surgery, and neurosurgery. A low short-term complication rate was observed (5.6%), and there was a trend toward nonsurgical management within the study population. Ten patients returned for a long-term follow-up. Of these, the 2 patients who underwent cranialization experienced as many or more long-term complications compared with the patients treated by other modalities. These complications included abnormal frontal bone contour with bony discontinuity and altered sensation in the distribution of the trigeminal nerve.The demonstrated trend toward nonsurgical management of frontal sinus fractures seems to be safe. In the limited group of patients who returned for follow-up, more long-term complications were observed in the patients who underwent cranialization. However, a larger long-term follow-up cohort will be necessary to elucidate the relationship between treatment modality and long-term outcomes and complications.
View details for DOI 10.1097/SCS.0000000000001105
View details for PubMedID 25377963
Caries management by risk assessment in a cleft and craniofacial center. journal of craniofacial surgery 2014; 25 (6): e529-36
Patients with craniofacial anomalies have an increased incidence of dental caries. The prevention program "Caries Management By Risk Assessment" (CAMBRA) has been previously validated but has not yet been introduced at a widespread level in a medical setting, particularly for this high-risk population.In this cross-sectional study, we aimed to evaluate the feasibility of implementing CAMBRA during the medical visit at an institutional tertiary care center, which treats children with craniofacial anomalies. The study included 161 participants aged 1 to 18 years. Patients and parents received a personalized educational session, toothbrushing tutorial, and fluoride varnish application. We assessed the prevalence of dental caries, caries risk factors, and knowledge of oral hygiene in this patient population.The overall caries prevalence in this group was higher than average (57% compared with 42%, according to the Centers for Disease Control and Prevention). The most prevalent risk factors were developmental delay, deep pits/fissures, low socioeconomic status, orthodontic appliances, and carbohydrate snacks. The greatest predictors of dental caries were having 1 or more risk factors and having low socioeconomic status. In summary, children with craniofacial anomalies were at high risk for dental caries, with high rates of risk factors and low rates of preventive factors.Our findings revealed that basic oral hygiene standards are not being met in this high-risk population, highlighting the need for implementation of protocols such as CAMBRA. The results of this study can aid healthcare workers in craniofacial centers and children's hospitals to improve the understanding of oral hygiene and dental care of their patients.
View details for DOI 10.1097/SCS.0000000000001040
View details for PubMedID 25377980
Computer-Aided Trauma Simulation System With Haptic Feedback Is Easy and Fast for Oral-Maxillofacial Surgeons to Learn and Use JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 2014; 72 (10): 1984-1993
Cell viability after osteotomy and bone harvesting: comparison of piezoelectric surgery and conventional bur INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 2014; 43 (8): 966-971
The aim of this study was to evaluate and compare the influence of a piezoelectric device versus a conventional bur on osteocyte viability and osteoblast and osteoclast activity using an in vivo mouse model. Osteotomies were created and bone grafts were harvested using either a conventional bur or a piezoelectric device; the resulting injuries and bone grafts were evaluated over an extended time-course using molecular and cellular assays for cell death (TUNEL assay), cell viability (4',6-diamidino-2-phenylindole (DAPI) staining), the onset of mineralization (alkaline phosphatase activity), and bone remodelling (tartrate-resistant acid phosphatase activity). Osteotomies created with a piezoelectric device showed greater osteocyte viability and reduced cell death. Bone grafts harvested with a piezoelectric device exhibited greater short-term cell viability than those harvested with a bur, and exhibited slightly more new bone deposition and bone remodelling. The difference in response of osteocytes, osteoblasts, and osteoclasts to bone cutting via a bur and via a piezoelectric device is negligible in vivo. Given the improved visibility and the margin of safety afforded by a piezoelectric device, they are the instrument of choice when cutting or harvesting bone to preserve soft tissue.
View details for DOI 10.1016/j.ijom.2013.11.018
View details for Web of Science ID 000339601900009
Body Dysmorphic Disorder and Psychological Distress in Orthognathic Surgery Patients JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 2014; 72 (8): 1553-1558
Body dysmorphic disorder (BDD) is a distressing condition involving preoccupation with an imagined or exaggerated deformity. The purpose of our study was to investigate the presence of BDD and its comorbidity with anxiety, depression, and obsessive-compulsive disorder (OCD) in patients undergoing orthognathic surgery (OS).The present prospective study included 99 patients from the outpatient oral and maxillofacial surgery clinic at Stanford University who requested OS. The incidence of BDD, depression, anxiety, and OCD was assessed preoperatively using validated self-report measures. To determine the prevalence of Axis I psychological symptoms among patients, the descriptive and bivariate statistics were computed. P < .05 was considered significant.In our sample, 13 patients (13%) screened positive for BDD. We did not find any significant correlations between the presence of BDD and gender, race, age, or marital status. Depressive symptoms were reported by 42% of the patients, OCD symptoms by 29%, and mild, moderate, and severe anxiety by 14%, 5%, and 4%, respectively. Using Spearman correlations, we found significant correlations between BDD and anxiety, depression, and OCD (P < .01).The results of the present study suggest that the rates of BDD, depression, anxiety, and OCD are high in patients undergoing OS. Furthermore, we found a strong correlation between BDD and anxiety, OCD, and depression in these patients. Future studies are necessary to determine the postoperative changes in these psychological disorders and whether these changes are affected by having positive BDD screening results at baseline.
View details for DOI 10.1016/j.joms.2014.01.011
View details for Web of Science ID 000341361000021
Efficacy of Bone Healing in Calvarial Defects Using Piezoelectric Surgical Instruments JOURNAL OF CRANIOFACIAL SURGERY 2014; 25 (1): 149-153
This study compared bone healing following the use of 2 piezoelectric surgery units or conventional mechanical cutting with carbide and diamond drills to explore their future applications for bone surgery.Subcritical-size (approximately 1.5-2 mm) calvarial defects were created in the parietal bones of adult mice. Following defect standardization, a full-thickness semicircular defect was created on the parietal bones of 12 mice divided into 4 groups: carbide bur, Surgystar, diamond bur, and Piezoelectric System. Hard tissue healing was assessed using micro-computed tomography at 1 day, 2 weeks, 4 weeks, and 8 weeks after surgery.At 4 weeks, the Surgystar group and Piezoelectric System group showed a significant difference from the carbide group. The Surgystar and Piezoelectric System groups did differ from the diamond group. At 8 weeks, the Surgystar and Piezoelectric System groups differed significantly from the carbide and diamond groups. The fraction of healing results over the 8 weeks demonstrated that the Surgystar group had a significantly higher bone healing percentage than did the carbide group (P = 0.001) and the diamond group (P = 0.026), but it did not differ significantly from the Piezoelectric System group (P = 0.420).The Surgystar and Piezoelectric System are suitable for bone osteotomy and provide faster bone healing in comparison with mechanical instrumentation.
View details for DOI 10.1097/SCS.0000000000000382
View details for Web of Science ID 000335928600068
View details for PubMedID 24406569
Transverse stability of the proximal segment after bilateral sagittal split ramus osteotomy for mandibular setback surgery INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 2013; 42 (8): 994-1000
This study aimed to evaluate the correlation between the transverse displacement of the proximal segment after bilateral sagittal osteotomy for mandibular setback and the amount and design of the mandibular setback. Patients who underwent either bilateral sagittal split ramus osteotomy (BSSRO) alone or two-jaw surgery were selected, and cephalographic postero-anterior (PA) measurements were taken pre-operatively (T1), immediately post-operatively (T2), and at follow-up (T3). The inter-gonal (IG) and inter-ramal (IR) width increased immediately after surgery, but decreased to the initial value during follow-up (P=0.002; IR, P=0.046). Only the immediate IG changes after surgery correlated with the amount of mandibular setback (P=0.009). The IG changes were significant in the symmetric group, but not in the asymmetric group. There was no difference in the IG and IR changes between the symmetric group and the asymmetric group. The immediate IG change in two-jaw patients with symmetric setback showed correlation with the setback amount. The gonial width of the deviated group showed more significant changes than that of the non-deviated group. There was no difference in the unilateral gonial width between the deviated and the non-deviated group, but the difference was significant for the unilateral ramal angle between the two groups. These correlations will be helpful in predicting post-surgical results for patients.
View details for DOI 10.1016/j.ijom.2013.01.021
View details for Web of Science ID 000321481800012
View details for PubMedID 23538214
Decisions, Decisions: How Program Diversity Influences Residency Program Choice JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS 2011; 213 (2): 294-305
Recent studies suggest that students' feelings of fit with a residency program substantially influence students' ranking of the program. As diversity issues become increasingly focal concerns, we investigate how perception of gender and racial diversity of a program influences students' rankings of the program. We focus on students pursuing surgical specialties and ask whether diversity concerns are more prominent among applicants to surgical programs than among applicants to nonsurgical programs.We invited all interviewees at all residency programs at the Stanford University School of Medicine to participate in our study in the spring of 2009. Nineteen residency programs, amounting to 1,657 residency interviewees, participated. Sixty-eight percent (n = 1,132) responded to the survey.Women and under-represented minority applicants differ in their assessments from male and non-under-represented minority applicants because women applying to surgical programs and under-represented minority students are less likely than others to perceive their prospective programs as diverse. However, perceived program diversity is an important factor that positively influences the program ranking decision for women and minorities pursuing surgical training.Surgical training programs that promote gender and racial diversity will likely be more successful in attracting women and minority students because women and minorities are especially sensitive to program diversity in both their perceptions and rankings of programs. Promoting women and minorities within programs and connecting women and minority applicants to outreach programs and mentors is pertinent to the recruitment of these traditionally under-represented groups to surgical programs.
View details for DOI 10.1016/j.jamcollsurg.2011.04.026
View details for Web of Science ID 000293843300015
View details for PubMedID 21641834
Academic Couples: Implications for Medical School Faculty Recruitment and Retention JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS 2011; 212 (3): 310-319
Academic couples constitute 36% of the US professoriate. Universities are in the midst of a major transition in hiring practices to support these and other faculty with working partners. However, less is known about academic couples among medical school faculty and surgical specialties specifically. This study was designed to address this gap.In 2006-2007, the Michelle R Clayman Institute for Gender Research at Stanford University designed and administered the "Managing Academic Careers Survey" to nearly 30,000 full-time faculty across all academic fields at leading research universities nationwide. This study included 2,475 medical school faculty survey respondents at 12 participating institutions. Main outcomes measures were academic partner status; number of journal articles/chapters during career; and applications to other academic position(s) in last 5 years.A total of 73.3% of medical school faculty respondents were in dual-career partnerships (where both partners actively pursue employment) and 32.2% had an academic partner. Sixty-nine percent of academic partners were also in medical schools. Women faculty were more likely than men to have an academic partner. Among surgery faculty, 40% of women had an academic partner, as compared with 29.3% of men. In fully adjusted regression models, faculty with academic partners had higher publication counts than other faculty, and had higher odds of applying to other academic positions.Academic couples constitute one-third of all medical school faculty. They represent a productive and potentially mobile component of the medical faculty workforce. Because women had a higher rate of academic partnering, dual-career academic hiring policies are especially important for recruitment and retention of female faculty in surgical specialties.
View details for DOI 10.1016/j.jamcollsurg.2010.11.005
View details for Web of Science ID 000289427400006
View details for PubMedID 21296007
Principles of implant-based reconstruction and rehabilitation of craniofacial defects. Craniomaxillofacial trauma & reconstruction 2010; 3 (1): 33-40
The final stages of reconstruction following craniofacial trauma or tumor resection often involve the fitting of prostheses. Development of osseointegrated implants for retention of prostheses has improved function and aesthetic outcome. Placement of osseointegrated implants requires coordinated care from multiple specialists and a lifetime commitment of the patient. The workup and surgical treatment algorithms for placement of intraoral compared with extraoral implants are discussed. The quality and quantity of bone available are the most important factors influencing design and placement. The long-term retention of implants is influenced by implant site, local tissue bed preparation, and hygiene. Osseointegrated implants are a part of the complete rehabilitation of patients with craniomaxillofacial defects. Although final fitting and maintenance of prostheses is completed by prosthodontists and patients, successful placement and preservation of implants is affected largely by the plan set forth by the reconstructive surgeon.
View details for DOI 10.1055/s-0030-1249372
View details for PubMedID 22110816
Embryonic origin and Hox status determine progenitor cell fate during adult bone regeneration DEVELOPMENT 2008; 135 (17): 2845-2854
The fetal skeleton arises from neural crest and from mesoderm. Here, we provide evidence that each lineage contributes a unique stem cell population to the regeneration of injured adult bones. Using Wnt1Cre::Z/EG mice we found that the neural crest-derived mandible heals with neural crest-derived skeletal stem cells, whereas the mesoderm-derived tibia heals with mesoderm-derived stem cells. We tested whether skeletal stem cells from each lineage were functionally interchangeable by grafting mesoderm-derived cells into mandibular defects, and vice versa. All of the grafting scenarios, except one, healed through the direct differentiation of skeletal stem cells into osteoblasts; when mesoderm-derived cells were transplanted into tibial defects they differentiated into osteoblasts but when transplanted into mandibular defects they differentiated into chondrocytes. A mismatch between the Hox gene expression status of the host and donor cells might be responsible for this aberration in bone repair. We found that initially, mandibular skeletal progenitor cells are Hox-negative but that they adopt a Hoxa11-positive profile when transplanted into a tibial defect. Conversely, tibial skeletal progenitor cells are Hox-positive and maintain this Hox status even when transplanted into a Hox-negative mandibular defect. Skeletal progenitor cells from the two lineages also show differences in osteogenic potential and proliferation, which translate into more robust in vivo bone regeneration by neural crest-derived cells. Thus, embryonic origin and Hox gene expression status distinguish neural crest-derived from mesoderm-derived skeletal progenitor cells, and both characteristics influence the process of adult bone regeneration.
View details for DOI 10.1242/dev.023788
View details for Web of Science ID 000258395500003
View details for PubMedID 18653558
Image-guided surgical navigation in implant-based auricular reconstruction JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 2008; 66 (6): 1302-1306
Haptic simulation of bone placement based on voxel models INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY 2007; 2: S195-S196
Visuohaptic simulation of bone surgery for training and evaluation IEEE COMPUTER GRAPHICS AND APPLICATIONS 2006; 26 (6): 48-57
Visual and haptic simulation of bone surgery can support and extend current surgical training techniques. The authors present a system for simulating surgeries involving bone manipulation, such as temporal bone surgery and mandibular surgery, and discuss the automatic computation of surgical performance metrics. Experimental results confirm the system's construct validity.
View details for Web of Science ID 000241568100008
View details for PubMedID 17120913
Virtual 3D planning and guidance of mandibular distraction osteogenesis. Computer aided surgery 2006; 11 (2): 51-62
We present a system for 3D planning and pre-operative rehearsal of mandibular distraction osteogenesis procedures. Two primary architectural components are described: a planning system that allows geometric bone manipulation to rapidly explore various modifications and configurations, and a visuohaptic simulator that allows both general-purpose training and preoperative, patient-specific procedure rehearsal. We provide relevant clinical background, then describe the underlying simulation algorithms and their application to craniofacial procedures.
View details for PubMedID 16782639
An Interactive Simulation Environment for Craniofacial Surgical Procedures MEDICINE MEETS VIRTUAL REALITY 13: THE MAGICAL NEXT BECOMES THE MEDICAL NOW 2005; 111: 334-341
Recent advances in medical imaging and surgical techniques have made possible the correction of severe facial deformities and fractures. Surgical correction techniques often involve the direct manipulation - both relocation and surgical fracture - of the underlying facial bone. The work presented here introduces an environment for interactive, visuohaptic simulation of craniofacial surgical procedures, with an emphasis on both mandibular distraction procedures and traditional orthognathic surgeries. The simulator is intended both for instruction and for procedure-specific rehearsal, and can thus load canonical training cases or patient-specific image data into the interactive environment. A network module allows remote demonstration of procedure technique, a form of 'haptic tutoring'. This paper discusses the simulation, haptic feedback, and graphic rendering techniques used to drive the environment. Particular emphasis is placed on techniques for fracture and subsequent rigid manipulation of bone structures, a key component of the relevant procedures.
View details for Web of Science ID 000273828700068
View details for PubMedID 15718755
A virtual training environment for mandibular distraction procedures CARS 2005: COMPUTER ASSISTED RADIOLOGY AND SURGERY 2005; 1281: 1375-1375
Automated 3D distraction osteogenesis planning in craniofacial surgery 4TH INTERNATIONAL CONGRESS OF MAXILLOFACIAL AND CRANIOFACIAL DISTRACTION 2003: 239-243
Three-dimensional photography for calculating pre- and post-operative volume in breast surgery CARS 2003: COMPUTER ASSISTED RADIOLOGY AND SURGERY, PROCEEDINGS 2003; 1256: 1355-1355
Three-dimensional simulation and prediction of craniofacial surgery. Orthodontics & craniofacial research 2003; 6: 102-107
The treatment of patients with complex facial deformities is one of the most challenging multidisciplinary tasks in plastic surgery. Due to advancements in medical technology and surgical techniques in the last 20 years correction of severe malformations has become possible and is performed by highly specialized teams frequently in a single operation. Recent developments in three-dimensional (3-D) imaging techniques have already greatly facilitated diagnosis of complex craniofacial deformities. Computer-based simulation methods for surgical procedures that are based on imaging data have the potential to improve surgical treatment by providing the ability to perform 'virtual surgery' preoperatively and thus reduce patient risk and morbidity intraoperatively. A method is presented for interactive computer-assisted craniofacial plastic surgery planning and visualization, especially simulation of soft tissue changes using an experimental Craniofacial Surgery Planner. The system computes non-linear soft-tissue deformation because of bone realignment. It is capable of simulating bone cutting and bone realignment with integrated interactive collision detection. Furthermore, soft-tissue deformation and cutting due to surgical instruments can be visualized. Simulation processes are based on an individual patient's preoperative 3-D computed tomography and on a 3-D, photo-realistic model of the patient's preoperative appearance obtained by a laser range scanner. Very fast and robust prediction of non-linear soft-tissue deformation is computed by optimizing a non-linear cost function.
View details for PubMedID 14606542
Virtual 3D planning and guidance of mandibular distraction osteogenesis CARS 2003: COMPUTER ASSISTED RADIOLOGY AND SURGERY, PROCEEDINGS 2003; 1256: 382-388
Estimation of soft-tissue model parameters using registered pre- and postoperative facial surface scans MEDICINE MEETS VIRTUAL REALITY 02/10 2002; 85: 520-522
Computer-based techniques for the simulation of craniofacial surgical procedures and for the prediction of the surgical outcome have been shown to be very useful. However, the assessment of the accuracy of the simulated surgical outcome is difficult. In this paper, a technique is described which allows to compare the simulated surgical outcome and the actual surgical result. The simulated postoperative patient's appearance is compared to a second surface scan which is obtained postoperatively. The pre- and postoperative surface scans, which are different due to the surgery, are registered employing a robust registration method which minimizes distances of corresponding points. Parameters of the soft-tissue model can be adapted with respect to minimized differences of corresponding points of the simulated postoperative and the actual postoperative surface of a patient's face.
View details for Web of Science ID 000176591900094
View details for PubMedID 15458144
Computer-aided 3-D simulation and prediction of craniofacial surgery: a new approach JOURNAL OF CRANIO-MAXILLOFACIAL SURGERY 2001; 29 (3): 156-158
In plastic and reconstructive craniofacial surgery, careful preoperative planning is essential. In complex cases of craniofacial synostosis, rapid prototyping models are used to simulate the surgery and reduce operating time. Recently, 3-D CT model surgery has been introduced for presurgical planning and prediction of the postoperative result.For simulation of craniofacial surgery a computer-based system was developed that allows visualization and manipulation of CT-data using computer graphics techniques. Surgical procedures in all areas of the bony skull can be performed interactively.The case of a child with scaphocephalus is presented. Surgery is planned using the craniofacial surgery simulator described above.The computer-based interactive surgery simulation systems presented here allow precise visualization of craniofacial surgery. The accurate computer-aided 3-D simulation of bone displacements is also the prerequisite for transfer of the simulated surgery using a navigation system for surgery. Thus the preoperatively planned procedure could be transferred directly to the operating table.
View details for Web of Science ID 000169607100005
View details for PubMedID 11465254
Correlation of telomerase activity, clinical prognosis and therapy in oral carcinogenesis ANTICANCER RESEARCH 2001; 21 (2A): 1057-1063
Telomerase activity is associated with most malignant tumors. To evaluate the role of telomerase reactivation as a diagnostic and prognostic marker in oral carcinogenesis activity was investigated in mortal and immortal cell lines in eight oral leukoplakias (OL) and 46 oral squamous cell carcinomas (OSCC). Activity was also investigated in 13 histopathologically unaffected mucosas from distant sites or tumor-free margins of the same patients using a modified, highly sensitive, non-radioactive telomeric repeat amplification protocol (TRAP). This was correlated with histopathological stages and the clinical course of the disease. 50% of OL and 46% of OSCC showed activity. One patient with positive, high dysplastic OL developed an OSCC 11 month later. One of three specimens of adjacent tissue presented activity and a recurrence occurred after 6 months. Out of 10 tissues of distal normal mucosa, 2 demonstrated activity which could also be proved in the corresponding tumor. Detection of telomerase reactivation may be a novel method for early detection of immortalised cell clones and malignant cells in histopathologically normal oral squamous epithelium.
View details for Web of Science ID 000169012300032
View details for PubMedID 11396140
Computer-aided 3-D simulation and prediction of craniofacial surgery: a new approach. Journal of maxillofacial surgery 2001; 29 (3): 156-158
Background: In plastic and reconstructive craniofacial surgery, careful preoperative planning is essential. In complex cases of craniofacial synostosis, rapid prototyping models are used to simulate the surgery and reduce operating time. Recently, 3-D CT model surgery has been introduced for presurgical planning and prediction of the postoperative result. Objective: For simulation of craniofacial surgery a computer-based system was developed that allows visualization and manipulation of CT-data using computer graphics techniques. Surgical procedures in all areas of the bony skull can be performed interactively. Results: The case of a child with scaphocephalus is presented. Surgery is planned using the craniofacial surgery simulator described above. Conclusion: The computer-based interactive surgery simulation systems presented here allow precise visualization of craniofacial surgery. The accurate computer-aided 3-D simulation of bone displacements is also the prerequisite for transfer of the simulated surgery using a navigation system for surgery. Thus the preoperatively planned procedure could be transferred directly to the operating table. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.
View details for PubMedID 11403552
Realistic modeling of elasto-mechanical properties of soft tissue and its evaluation CARS 2001: COMPUTER ASSISTED RADIOLOGY AND SURGERY 2001; 1230: 51-56
3-D simulation of craniofacial surgical procedures I O S PRESS. 2001: 502-508
An integrated system for simulating craniofacial surgical procedures is presented. The system computes nonlinear soft-tissue deformation due to bone realignment. It is capable of simulating bone cutting and bone realignment with integrated interactive collision detection. Furthermore, soft-tissue deformation and cutting due to surgical instruments can be visualized. The system has been tested with several individual patient data sets. Simulation processes are based on a 3-D model of a patient's preoperative bone structure of the skull derived from a computer tomography scan and on a 3-D, photorealistic model of the patient's preoperative appearance obtained by a laser range scanner. The multi-layer soft-tissue model is represented by nonlinear springs. Very fast and robust prediction of nonlinear soft-tissue deformation is computed by optimizing a nonlinear cost function.
View details for Web of Science ID 000169103300095
View details for PubMedID 11317798
I-FISH control of CGH-detected gain of DNA sequence copy number in oral squamous cell carcinomas (OSCC) ANTICANCER RESEARCH 2000; 20 (1A): 427-432
Interphase fluorescence in situ hybridization (I-FISH) was used to control the gain of genomic material in 21 human oral squamous cell carcinomas (OSCC) which had been detected by comparative genomic hybridization (CGH). DNA probes for 3q27, for 5p15.2, and for the protooncogenes c-myc (8q24) and c-abl (9q34), were used for I-FISH examination of the interphase nuclei of paraffin sections of the tumors. The corresponding alphoid DNA probes for the centromeric regions of the respective chromosomes and a probe on 5q served as controls of aneusomy. Previous examinations with int2 (11q13) and erbB2 (17q11.2-13) were included for comparison. I-FISH analysis detected a gain of 3q27 in 17, of 5p15.2 in 7, of c-myc in 14, of c-abl in 10, and formerly, of int2 in 12 and of erbB2 in 10 of the examined tumors. There was an overall confirmation of the CGH findings by the I-FISH data in 63% (36-83% depending on the studied chromosomal site), and vice versa of 76% of the I-FISH results by the CGH data. Based on these results it is recommended to use a combination of both I-FISH and CGH for the detection of genomic changes in human solid tumors as the data obtained by both techniques ideally complete each other. For this reason both techniques have now enriched the spectrum of molecular histopathology.
View details for Web of Science ID 000086326500065
View details for PubMedID 10769691
Interactive simulation environment for craniofacial surgical planning CARS 2000: COMPUTER ASSISTED RADIOLOGY AND SURGERY 2000; 1214: 47-52
Optimization approaches for soft-tissue prediction in craniofacial surgery simulation MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION, MICCAI'99, PROCEEDINGS 1999; 1679: 1183-1190
Efficient and robust soft tissue prediction in craniofacial surgery simulation using individual patient's data sets CARS '99: COMPUTER ASSISTED RADIOLOGY AND SURGERY 1999; 1191: 635-639
CGH-detected DNA sequence copy number amplifications can be confirmed by interphase-FISH: New possibilities for prognostic approaches in oral squamous cell carcinomas INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE 1998; 2 (5): 555-560
In order to control the data obtained by comparative genomic hybridization (CGH) on DNA sequence copy number amplifications, 20 oral squamous cell carcinomas (SCC) were subjected to interphase fluorescence in situ hybridization (I-FISH) examination using specific DNA probes for the oncogenes int2 and erbB-2, and the corresponding centromeric probes of chromosomes 11 and 17. In all cases characterized by distinct peaks of the CGH profile on the critical chromosomal segment 11q13, these data could be clearly substantiated by the I-FISH analyses using the int2 probe and estimating the signal index, the int2/centromer 11 relation, and the fraction of nuclei with high int2 signal numbers. In addition, I-FISH detected smaller cell fractions with high signal numbers (and/or signal clusters) in some tumors which were not definitely conspicuous in CGH. In contrast to int2, erbB-2 amplification apparently does not play a major role in oral SCCs, as the blurred peaks of CGH profiles on chromosome 17ql 1.2-q12 corresponded well with the findings of I-FISH using the erbB-2 probe. Gain of a whole chromosome 17 is apparently a rather common feature of these tumors. In conclusion, the combination of interphase FISH with oncogene-specific probes and CGH is regarded as a valuable means of practical molecular cytogenetic analysis of oral SCCs which could eventually achieve high practical importance in the pathologic analysis of these tumors and in prognosis of their development.
View details for Web of Science ID 000076967700005
View details for PubMedID 9858651
Gain of DNA copy number on chromosomes 3q26-qter and 5p14-pter is a frequent finding in head and neck squamous cell carcinomas INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE 1998; 2 (2): 173-179
Proliferative activity and loss of function of tumour suppressor genes as 'biomarkers' in diagnosis and prognosis of benign and preneoplastic oral lesions and oral squamous cell carcinoma BRITISH JOURNAL OF ORAL & MAXILLOFACIAL SURGERY 1998; 36 (4): 252-260
Oral cancer is a disease of the elderly and is closely connected with cigarette smoking and alcohol consumption. Since the successful introduction of multidisciplinary treatment, the survival rate has not changed. Because of the high mortality and potentially disfiguring treatment, today's efforts are aimed at eliminating risk factors, chemoprophylaxis, improvement in diagnostic procedures, and understanding of the genetic mechanisms of oral carcinogenesis. Immunohistochemical and molecular biology analysis of biopsy tissue and cell lines of preneoplastic and neoplastic lesions that originate from the oral mucosa have shown that alterations in tumour suppressor genes such as p53 and Rb gene may have an important role in oral carcinogenesis and may be potentially useful prognostic 'biomarkers' in oral carcinogenesis. Statistical analysis of immunohistochemical data from 216 patients did not identify significant or consistent differences of p53, MDM2, or RB expression with respect to stage of disease, malignant transformation, metastatic node involvement, recurrence, or survival. Nevertheless, p53 overexpression seems to correlate strongly with histological progression of the disease, which confirms the importance of p53 alterations in oral carcinogenesis. Overexpression of p53 is usually found in the less differentiated proliferating cells in benign and malignant oral lesions. Assessment of the proliferating activity is possible by immunohistochemical staining with monoclonal antibodies against proliferating nuclear antigen and Ki-67. Statistical analysis shows that overexpression of p53 combined with high proliferative activity predicts a less favourable course of disease in oral squamous cell carcinoma.
View details for Web of Science ID 000075516900003
View details for PubMedID 9762452
Pattern of genomic imbalances in oral squamous cell carcinomas with and without an increased copy number of 11q13 INTERNATIONAL JOURNAL OF ONCOLOGY 1998; 12 (5): 1151-1155
Among 23 squamous cell carcinomas (SCC) of the oral cavity which were screened for DNA copy number alterations (CNAs) using comparative genomic hybridization, 14 showed a gain of, and 5 of these 14 even an amplification of band 11q13. Amplification of 11q13 was also detected in three of the four studied SCC cell lines and was confirmed by interphase FISH. The number of CNAs in addition to 11q13 varied from 14 to 47 in these carcinomas. All these tumors had seven other specific CNAs in common, i.e. gain on 1p36.3-36.6, 5p15, 9q34, 12p12-13, 14q32, 19 and 20q, all but one showed also an increase of copy number in 7p22, 8q24, 10q26, 12q26, 15q24-25, 16p, 16q23-24, 17q and 22q12-qter. These imbalances were distinctly rarer in the tumors without CNA in 11q13. Loss of material apparently played a minor role in these tumors with gain of 11q13, the most frequent losses (3p12-14 and 5q21) being present in 10 of the 14 cases and loss of 9p13-21 in 5/14 tumors. The three tumors with the highest number of CNAs in addition to 11q13, were histologically classified as pT4, three of the five tumors with 11q13 amplification were highly node-positive (pN 2b-2c). Two of the pT4 tumors shared as many as 23 specific chromosomal segments affected by CNA. Thus, gain of 11q13, though being found at different stages of karyotypic evolution, is apparently associated with a rather specific pattern of other CNAs and involved in progressed stages of malignancy in oral squamous cell carcinoma. In addition, the proportion of patients deceased within one year after diagnosis was clearly higher in the group whose tumors showed an increased 11q13 copy number as compared to the group without this increase. This could point to an association of gain in 11q13 and aggressiveness of the respective tumor.
View details for Web of Science ID 000073176200026
View details for PubMedID 9538142
Oral squamous cell carcinomas are characterized by a rather uniform pattern of genomic imbalances detected by comparative genomic hybridisation ORAL ONCOLOGY 1998; 34 (3): 186-190
Total genomic DNA sampled from 20 oral squamous cell carcinomas (SCCs) and from four SCC cell lines, was examined for genomic imbalances using comparative genomic hybridisation (CGH). Gains and losses of DNA copy number aberrations (CNAs) were found in the primary tumours, but also in the cell lines at a varying number. The patterns of CNAs proved to be rather peculiar in oral SCCs, gains of genetic material clearly dominating compared with losses, and a rather high uniformity of these patterns was an impressive finding. Hypersomies of whole chromosomes, e.g. numbers 17 and 19 or of whole chromosome arms, e.g. 20q, were particularly evident. The segments most frequently gained in oral SCCs were 3q26-q27, 5p15 and 9q34 (16 of 20 tumours each), as well as 1p36.3, 8q24, 10q26, 19 and 20q (15/20 each). Among the 15 tumours with more than 10 CNAs, all showed these imbalances. 11q13 was a band often involved in increases (14/20 tumours), but in several tumours was involved in amplification of DNA copy number. Several other chromosomal segments over represented in more than 60% of the tumours, as, for example, 12q24, 15q22-q24, 16p13.2 and 17q (14/20 tumours each), 6q26-qter, 7p22, 12p12.2-p13, 14q31-q32.2 (13/20) and 1q32-q41, 2q37, 16q23-q24 (12/20 each). In contrast, loss of material affected only a few chromosomal segments, as, for example, 3p12 (12 of the 20 tumours), 5q21 (10/20), 6q13 (8/20). The peculiarities of these findings, in some respect, differ from those found in other epithelial tumours, suggesting a high impact of environmental factors in the generation and progression of these tumours.
View details for Web of Science ID 000074226900005
View details for PubMedID 9692052
p53 mutation and detection of p53 protein expression in oral leukoplakia and oral squamous cell carcinoma ANTICANCER RESEARCH 1998; 18 (3B): 2031-2036
In many studies the detection of p53 protein by immunohistochemistry (IHC) with one antibody is assumed to be consistent with a mutation of the gene. To determine the correlation of protein detection by immunohistochemistry and gene mutation, paraffin embedded specimens of 60 oral leukoplakias (OL) and 73 oral squamous cell carcinomas (OSCC) were analysed by IHC with two different antibodies (Do7; Pab 1801), PCR-SSCP and sequencing. In 98% of OLs and 94% of OSSCs p53 protein expression was detected with at least one antibody. Only 49% of all tissue specimen were positive with both antibodies. Molecular analysis of the same specimen showed mutations of the p53 gene in 13.3% of OLs and 9, 6% of OSCCs. p53 protein expression was not detected by IHC in 3 out of 7 OSCC with p53 mutations. According to these results detection of p53 expression by IHC is not always correlated with p53 gene mutation and failure to detect p53 protein by IHC does not prove the absence of mutation of the gene in the carcinogenesis in the oral mucosa.
View details for Web of Science ID 000074737400025
View details for PubMedID 9677462
Deformable modeling of facial tissue for craniofacial surgery simulation. Computer aided surgery 1998; 3 (5): 228-238
While deformable object modeling has been studied by computer graphics specialists for more than two decades, only a few applications in the field of surgical simulation have been developed which provide both real-time and physically realistic modeling of complex, nonlinear tissue deformations. Particularly in craniofacial surgery, the prediction of soft-tissue changes--which result from alterations in the underlying bone structure--is critical to the surgical outcome. The prediction these tissue changes and, therefore, the prognosis of the postoperative appearance of the patient, is still based on empirical studies of the relationship between bone and tissue movements: There exists no physical model which takes into account the individual patient anatomy to simulate the resulting tissue changes during craniofacial surgery. In this article we present two different deformable tissue models which are intergrated in an interactive surgical simulation test bed. Both techniques allow precise preoperative simulation of the resulting soft tissue changes during craniofacial surgery and visualization of the patient's postoperative appearance. The different deformable models are described in detail and both are applied to the same craniofacial case study. The simulation results are shown and compared with regard to the speed and accuracy of the prediction of the patient's postoperative appearance.
View details for PubMedID 10207647
[p53 as a biomarker in radiotherapy of carcinoma of the mouth cavity]. Mund-, Kiefer- und Gesichtschirurgie : MKG 1998; 2 (1): 11-13
Multimodal therapy of oral squamous cell carcinomas today is based on surgery, radiotherapy and chemotherapy. Despite the combination of all three therapeutic options, there is still a large number of treatment failures and therefore major questions remain. Recent investigations suggest that mutations of the p53 tumor suppressor gene may account for some of the therapeutic failures. Inactivation of the gene may be an important determinant of the efficacy of today's multimodal therapy protocols. In 90 patients with squamous cell carcinomas of the oral cavity biopsy specimens were taken before and after preoperative radiochemotherapy. From all patients, biopsy and resection material was available for immunohistochemical analysis of p53. After radiation treatment, 51 patients (57%) showed a complete response; 39 patients (43%) only showed a partial response or did not respond at all. Among the responders, 82% of the pretherapeutic tumors were p53 positive, whereas among the nonresponders only 56% of the pretherapeutic tumors were p53 positive. The majority of the residual tumors were also p53 negative according to immunohistology after radiation treatment. In our study, detection of p53 protein by immunohistochemistry seemed to be connected with a more radiosensitive reaction of the tumors. Nevertheless, successful strategies for radiation therapy may need to take into account the tissue of origin and the status of p53 in the tumor.
View details for PubMedID 9522566
Gain of DNA copy number on chromosomes 3q26-qter and 5p14-pter is a frequent finding in head and neck squamous cell carcinomas. International journal of molecular medicine 1998; 2 (2): 173-179
Comparative genomic hybridization (CGH) was used to study genomic imbalances in 77 squamous cell carcinomas of the head and neck (HNSCC) and in four cell lines derived from oral carcinomas. Particular attention was paid to all tumors characterized by a gain of two specific chromosomal segments, i.e. 3q26-qter and 5p14-p15. The 57 tumors containing both or one of the two imbalances were compared with 20 tumors lacking both with regard to genomic complexity, as well as to associated genomic, histopathologic and clinical peculiarities. 60% of the oral, and 66% of the non-oral cancers exhibited a gain of 3q26-qter, while a gain of 5p14-p15 was found in 66% of the oral, but only in 48% of the non-oral tumors. 48% of all tumors were characterized by both gains together, 26% exhibited only one of the two alterations. It could be shown that presence of both, gain of 3q26-qter and 5p14-p15, was clearly associated with a significantly higher complexity of genomic changes which was not only expressed as a high frequency of DNA copy number alterations (CNAs) but was also connected with a considerable number of additional amplifications of various chromosomal segments and a high conformity of the patterns of genomic imbalances in these tumors. Clear differences of the extent and of the patterns of genomic imbalance could be observed between oral and non-oral tumors. With respect to histopathological parameters, no clear association could be found for specific imbalances to the grade of differentiation, nor the invasiveness or metastatic status of the tumors. However, a higher number of patients with tumors characterized by gain of 3q26-qter plus 5p14-p15 died within a short period (i.e. less than 15 months) after excision of the tumor compared to the group without these imbalances. The implications of these findings are discussed from the oncogenetic and clinical aspects and in comparison with other reports.
View details for PubMedID 9855685
Radiosensitivity and double-strand break rejoining in tumorigenic and non-tumorigenic human epithelial cell lines INTERNATIONAL JOURNAL OF RADIATION BIOLOGY 1997; 72 (1): 91-100
Radiosensitivity and repair of DNA damage induced by ionizing radiation and restriction enzymes were investigated in three human epithelial cell lines: two tumorigenic squamous carcinoma cell lines (SCC-4 and SCC-25), and a non-tumorigenic epidermal keratinocyte cell line (RHEK-1). Sensitivity to ionizing radiation was determined using a clonogenic cell survival assay, which showed SCC-4 to be more radiosensitive than SCC-25 and RHEK-1, which in turn displayed about equal sensitivity. Using DNA precipitation under alkaline conditions for the analysis of induction and repair of DNA single-strand breaks (ssb), an increased level of ssb induction was found for SCC-4 while the efficiency of ssb repair was about equal in all three cell lines. Using pulsed-field gel electrophoresis (PFGE) for the measurement of induction and repair of DNA double-strand breaks (dsb), no consistent differences were detected between the three cell lines. A plasmid reconstitution assay was used to determine the capacity to rejoin restriction enzyme-induced dsb in whole-cell extracts prepared from the three cell lines. In these experiments, dsb rejoining was shown to be significantly reduced in the most radiosensitive SCC-4 cell line while it was about equal in RHEK-1 and SCC-25. The results indicate that plasmid reconstitution in cell-free extracts is a sufficiently sensitive assay to detect differences in repair capacity among tumour cell lines of different radiosensitivity which remain undetectable by DNA precipitation and PFGE.
View details for Web of Science ID A1997XL96200010
View details for PubMedID 9246198
Adaptive surface data compression SIGNAL PROCESSING 1997; 59 (2): 211-220
Retinoid actions and implications for prevention and therapy of oral cancer INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 1996; 25 (1): 69-73
Squamous cell carcinomas of the oral cavity can be preceded by clinically obvious premalignant changes, and they have a high rate of incidence of development of second primary tumors. Recent studies suggest retinoids not only for the treatment of oral eukoplakia, but also for the prevention of second primaries. Although retinoids are promising therapeutic agents, their therapeutic potential has been limited by their undesirable side-effects. A complete network of nuclear receptors has now been identified that mediate the action of retinoids and can interfere directly with cell proliferation signals by interacting with transcription factors. It has recently been shown that retinoids with receptor-selective activities can be obtained that are likely to have fewer side-effects because of their restricted biologic activities.
View details for Web of Science ID A1996UA55600015
View details for PubMedID 8833305
Craniofacial surgery simulation VISUALIZATION IN BIOMEDICAL COMPUTING 1996; 1131: 541-546
p53 overexpression and cell proliferation as prognostic markers in head and neck cancer HEAD AND NECK CANCER - ADVANCES IN BASIC RESEARCH 1996; 1114: 321-325
Anatomy-based facial tissue modeling using the finite element method VISUALIZATION '96, PROCEEDINGS 1996: 21-?
Computer-aided craniofacial surgery CAR '96: COMPUTER ASSISTED RADIOLOGY 1996; 1124: 757-763
DETECTION OF P53 AND MDM2 PROTEIN EXPRESSION IN HEAD AND NECK CARCINOGENESIS ANTICANCER RESEARCH 1995; 15 (4): 1453-1457
Hyperplastic lesions of the oropharyngeal mucosa such as leukoplakia and oral lichen planus can eventually develop into squamous cell carcinomas (SCC) and provide an excellent model for multistage carcinogenesis. The development of carcinomas is assumed to be the result of the interaction of genetic factors, locally applied carcinogens and immunological unresponsiveness. Recently a novel gene termed mdm2 has been isolated that is found to be involved in transcriptional regulation and can inhibit p53 function by forming a complex with p53. In this study the immunohistochemical detection of the MDM2 protein in 186 paraffin embedded tissue sections of normal mucosa, premalignant, malignant and metastatic lesions of the oropharyngeal mucosa is reported for the first time. p53 protein expression was also investigated in the same tissue samples. The increase in the number of p53 and MDM2 positive biopsies was correlated with the dysplasia grade and the loss of differentiation in the premalignant and malignant lesions. In late stages of the disease the number of biopsies that expressed both p53 and MDM2 increased. Inactivation of p53 function in head and neck carcinogenesis may also be due to MDM2 binding. Detection of MDM2 protein expression by immunohistochemistry may be an important diagnostic tool in the future.
View details for Web of Science ID A1995RT07000051
View details for PubMedID 7654034
ADVANCES IN INTERACTIVE CRANIOFACIAL SURGERY PLANNING BY 3D SIMULATION AND VISUALIZATION INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 1995; 24 (1): 120-125
In craniofacial surgery careful preoperative planning is essential. Traditional preoperative work-up consists of cast model surgery, cephalometric prediction tracing and analysis of photographs. Recently, we introduced 3-dimensional (3D) computed tomography (CT) model surgery in our preoperative work-up and presurgical prediction of the postoperative result. However, only limited information can be extracted concerning soft tissue changes which are most important for the patients' postoperative appearance. We propose a new system which will allow a precise preoperative visualization of not only bony structures but also the soft tissue surfaces. 3D CT data of the skull are integrated with 3D surface data acquired by laser scanning. Based on the 3D CT data the bony structures are segmented automatically and processed interactively to simulate the planned surgical procedure. Afterwards, the 3D soft tissue changes resulting from the shifting of bony segments are computed. The postoperative appearance of the patient is visualized using computer animation techniques.
View details for Web of Science ID A1995QU46200009
View details for PubMedID 7782646
P53 EXPRESSION IN THE CARCINOGENESIS IN THE ORAL-MUCOSA JOURNAL OF CELLULAR BIOCHEMISTRY 1994; 56 (4): 444-448
Hyperplastic lesions of the oral mucosa such as leukoplakia and oral lichen planus can eventually develop into squamous cell carcinomas. In the clinical treatment of these lesions it would be very important to be able to predict the biological behaviour of an individual lesion. In 64 hyperplastic lesions and 85 squamous cell carcinomas of the oral mucosa, the expression of the mutant tumor suppressor gene p53 was investigated. A positive correlation was seen between the expression of the mutant tumor suppressor gene p53 and the grade of dysplasia of the lesions.
View details for Web of Science ID A1994QF98600003
View details for PubMedID 7890803
P53 AND PCNA EXPRESSION IN CARCINOGENESIS OF THE OROPHARYNGEAL MUCOSA ORAL ONCOLOGY 1994; 30B (6): 419-423
Hyperplastic lesions of the oral mucosa such as leukoplakia and oral lichen planus can eventually develop into squamous cell carcinomas (SCC) and provide an excellent model for multistage carcinogenesis. The development of carcinomas is assumed to be the result of interaction of genetic factors, locally applied carcinogens and immunological unresponsiveness. The purpose of this study was, therefore, to determine the role of alterations of the tumour suppressor gene p53, and the proliferation status of the lesions determined by PCNA expression. We investigated p53 and PCNA expression in 265 tissue sections of normal mucosa, premalignant, malignant and metastatic lesions of the oral mucosa by immunohistology. Quantitative analysis showed a gradual increase in PCNA expression from normal mucosa to moderately differentiated SCC. p53 expression was detectable in benign premalignant lesions. The increase in the number of p53-positive biopsies was correlated with the dysplasia and loss of differentiation in the premalignant and malignant lesions.
View details for Web of Science ID A1994QC88500012
View details for PubMedID 7719225
P53 AND PCNA EXPRESSION IN MALIGNANT MELANOMAS OF THE HEAD AND NECK MUNKSGAARD INT PUBL LTD. 1994: 354-357
Mutation in the p53 tumor suppressor gene is the most common genetic alteration in human cancer. As in mutant p53 the protein is stabilised and the half-life is extended, it becomes detectable by immunohistological staining. p53 immunoreactivity thus seems to be a potential biomarker for the assessment of the oncogenic potential of malignant melanomas. In 103 tissue sections of primary and metastatic malignant melanomas of the head and neck detectable levels of p53 were only found in 3 of the primary tumors and in none of the metastases. At the same time the proliferation status of the malignant melanoma lesions was determined using the cell cycle specific antibody PCNA. 55 primary and metastatic tumors were stained with a PCNA-MAb to determine the proliferation activity of the tumors. The results of our immunohistochemical investigation suggest that immunoreactivity of p53 cannot be used to determine the malignant potential of melanomas in the head and neck. PCNA staining showed that the majority of the tumors and metastases were proliferating rapidly.
View details for Web of Science ID A1994PW15100013
View details for PubMedID 7886008
Langerhans cells in epithelial tumors and benign lesions of the oropharynx. In vivo 1994; 8 (4): 543-547
Hyperplastic lesions of the oral mucosa such as leukoplakia and oral lichen planus can eventually develop into squamous cell carcinomas. The development of carcinomas may be the result of the interaction of genetic factors, carcinogens and an impaired immune response. The presence of S-100 positive Langerthans cells in normal mucosa, premalignant and malignant lesions of the oral mucosa was investigated by immunohistology. Quantitative analysis showed that in benign lesions of the oral mucosa the average number of S-100 positive cells was much higher than in normal mucosa. In the neoplastic lesions the number of S-100 positive cells was in general lower than in the benign lesions and decreased even more with loss of differentiation. The data suggest that the infiltration of dendritic cells increases in benign lesions of the oral mucosa, implying a normal immunostimulatory potential, and decreases in malignant lesions in relation to the loss of differentiation in the tumors.
View details for PubMedID 7893981
P53 AND KI-67 EXPRESSION IN PRENEOPLASTIC AND NEOPLASTIC LESIONS OF THE ORAL-MUCOSA INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 1993; 22 (5): 285-288
Some lesions of the oral mucosa such as leukoplakia and erythroplakia may develop into squamous cell carcinoma (SCC). At present, however, there is no method available to predict malignant transformation. It is known that the grade of dysplasia is related to the potential malignant development, but this is unreliable as the only indicator. In 64 hyperplastic lesions and 85 SCC of the oral mucosa, a correlation between the expression of the mutated tumor-suppressor gene p53 and the dysplasia of the lesions was found. Ki 67 was used as a proliferation marker. The results imply that expression of mutated p53 is an indicator for potential malignant development in benign lesions of the oral mucosa.
View details for Web of Science ID A1993MC22500008
View details for PubMedID 8245568
CYSTS ASSOCIATED WITH LONG-STANDING IMPACTED 3RD MOLARS INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 1993; 22 (2): 110-112
Three patients are described in whom large cysts developed around third molars that had purposely been left in place. The cases presented emphasize the need for an adequate prospective study to evaluate the long-term morbidity of asymptomatic third molars that are left in place.
View details for Web of Science ID A1993LG55500012
View details for PubMedID 8320446
[Cranial reconstruction. A report on the 43rd Congress of the German Society for Oral and Facial Surgery at Cologne]. 1993: 1522-1524
[Reconstruction of the visceral cranium]. 1993: 1343-1345
[Special considerations in dental surgery procedures on organ transplantation patients]. Deutsche Zeitschrift fr Mund-, Kiefer- und Gesichts-Chirurgie 1991; 15 (6): 431-434
In 150 patients 366 (95%) of 385 dental surgery procedures performed prior to organ transplantations were free of complications. In 6 patients circumscribed wound infections occurred, and 5 post-operative hemorrhages as well as 2 injection hematomas were observed. In the group of patients where dental surgery was performed after organ transplantation, all 123 procedures were free of complications. Treatment of transplantation patients in the dental office requires a profound understanding of the complex clinical problems these patients might present, a good coordination of the required measures and close cooperation between the transplantation center and the attending dentist. Special considerations of the treatment of organ transplantation patients and the indications for dental surgery are discussed.
View details for PubMedID 1840132
THE FASCICULAR STRUCTURE OF THE LINGUAL NERVE AND THE CHORDA TYMPANI - AN ANATOMIC STUDY JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 1989; 47 (6): 607-609
Damage of the lingual nerve is one of the most common problems in oral surgery, especially during removal of the third molar. After microsurgery of the lingual nerve, there is a lack of regeneration of the gustatory fibers in comparison with the sensory fibers. The histologic investigation of ten human lingual nerve preparations showed that the chorda tympani fibers distribute widely in the fascicles of the lingual nerve. Therefore, after microsurgical reconstruction of the lingual nerve in the third molar region, the chance of the gustatory fibers meeting and regenerating is very low.
View details for Web of Science ID A1989U841300017
View details for PubMedID 2723860
PROSPECTIVE-STUDY ON THE QUESTION OF COMPLICATIONS SECONDARY TO THE TRANSPLANTATION OF TEETH IN THE PRESENCE OF AN ORO-ANTRAL COMMUNICATION DEUTSCHE ZAHNARZTLICHE ZEITSCHRIFT 1988; 43 (12): 1342-1344
COMPLICATIONS IN THE PLASTIC CLOSURE OF ORO-ANTRAL COMMUNICATIONS DEUTSCHE ZAHNARZTLICHE ZEITSCHRIFT 1988; 43 (12): 1335-1337