Apoptosis, proliferation and p12(doc-1) profiles in normal, dysplastic and malignant squamous epithelium of the Syrian hamster cheek pouch model

Disruption of the homeostatic balance between proliferation and apoptosis is widely believed to contribute to human oral carcinogenesis. Using the Syrian hamster oral cancer model, we examined normal, hyperplastic, dysplastic and malignant oral epithelium for the fraction of apoptotic, proliferating and p12(doc-1) expressing keratinocytes using the TUNEL assay, as well as PCNA and p12(doc-1) immunostaining, respectively. The percentage of TUNEL positive cells progressively increased from normal to dysplastic epithelium (P<0.0019), but returned to normal keratinocyte levels in the malignant epithelium (P<0.20). However, PCNA positive cells increased progressively through hamster oral malignant progression (P<0.0012). The overall ratio of apoptotic to proliferating keratinocytes remains similar until the transition between dysplastic and malignant epithelium, where the ratio is markedly reduced (P<0.05). p12(doc-1) labeling demonstrated a similar expression pattern (P<0.008). This study demonstrates that apoptosis, proliferation and the expression of p12(doc-1) reflects alterations reported during human oral carcinogenesis and supports the use of the Syrian hamster model for the further examination of these pathways.

Oral cancer in vivo gene expression profiling assisted by laser capture microdissection and microarray analysis

Large scale gene expression profiling was carried out on laser capture microdissected (LCM) tumor and normal oral epithelial cells and analysed on high-density oligonucleotide microarrays. About 600 genes were found to be oral cancer associated. These oral cancer associated genes include oncogenes, tumor suppressors, transcription factors, xenobiotic enzymes, metastatic proteins, differentiation markers, and genes that have not been implicated in oral cancer. The database created provides a verifiable global profile of gene expression during oral carcinogenesis, revealing the potential role of known genes as well as genes that have not been previously implicated in oral cancer.

From the chromosome to DNA: Restriction fragment length polymorphism analysis and its clinical application

Understanding how chromosomal alterations contribute to acquired and inherited human disease requires the ability to manage the enormous physical and informational complexity of the deoxyribonucleic acid (DNA) packaged within. Important concepts and techniques involved in the analysis of DNA include restriction enzymes, Southern blotting, and restriction fragment length polymorphism/linkage analysis. These techniques have been essential in the understanding and diagnosis of several syndromes associated with the head and neck. The purpose of this article is to introduce DNA structure, describe some techniques fundamental to DNA analysis, and provide a brief overview of the clinical applications of this technology with respect to dentinogenesis imperfecta and oral field cancerization.

The chromosome: cytogenetic analysis and its clinical application

PURPOSE

Chromosomes are highly structured, dynamic complexes of DNA and protein. The human genome consists of 46 chromosomes (22 paired autosomes and 2 sex chromosomes). Cytogenetic analysis provides a means to identify, as well as describe, chromosomes and disorder-related aberrations. The purpose of this article is to 1) introduce chromosome structure and alterations, 2) describe the technical fundamentals of cytogenetic analysis, and 3) provide a brief overview of the clinical applications of this technology.

Taste perception after lingual nerve repair

PURPOSE

This retrospective study evaluates patients' perception of taste after lingual nerve injury and repair. It is hypothesized that return of taste is a distinct neurophysiologic phenomenon related to specialized taste physiology and it does not correlate with specific, objective sensory return.

PATIENTS AND METHODS

During 1995 to 1996, 30 patients underwent microsurgical repair of lingual nerve injuries. Of these, 22 patients met the inclusion criteria for this study. Chart review documented the date and cause of injury, sensory examination, injury classification, procedures, operative findings, and postoperative sensory examination. A telephone questionnaire addressed whole mouth taste perception with normal daily eating. The questions asked were: 1) Was your sense of taste changed or abnormal after your nerve injury? and 2) Did your sense of taste recover after nerve repair?

RESULTS

All patients had a postinjury, prerepair sensory deficit on levels A, B, and C testing: neurotmesis (n = 14); and axonotmesis (n = 8). The mean time from injury to repair was 16 weeks (range, 3 to 41 weeks). Operative findings confirmed 12 Sunderland Class IV (partial transection) injuries and 10 Class V (complete transection) injuries. All patients had primary microsurgical repair without a nerve graft or entubulization. Postoperatively, 18 patients showed marked improvement in sensory testing at levels A, B and C, and 4 patients showed no significant change. A telephone interview regarding whole mouth taste perception indicated that 20 of 22 patients perceived changed, abnormal taste postinjury and pre-repair. Two patients reported normal taste perception. Postrepair, only 7 of 20 patients reported an increase or return of taste perception to a more normal level. The mean follow-up time was 80 weeks.

CONCLUSION

Most patients (20 of 22) with lingual nerve injuries in this study perceived whole mouth taste as abnormal. After nerve repair, although 82% (18 of 22) of patients had improvement in somatosensory function, whole mouth taste was perceived as improved by only 35% (7 of 20). It is proposed that the perception of whole mouth taste may not be related to the ability to perceive multiple sensory modalities, but rather to special sensory (taste) modality perception. Also, central changes may occur in the special sensory fibers that impact on the brainstem nucleus for taste (nucleus solitarius) and therefore the patient's perception of taste.

Intragenic mutation analysis of the human epidermal growth factor receptor (EGFR) gene in malignant human oral keratinocytes

Alteration in epidermal growth factor receptor (EGFR) expression is frequently associated with malignant transformation of epithelial tissues, including oral mucosa. This study examines the mutations in the coding region of the human EGFR gene in normal and malignant human oral keratinocytes. To examine the intragenic mutations in the human EGFR gene, a panel of normal and malignant human oral keratinocytes were examined by a nonisotopic RNase cleavage assay. Two consistent alterations were detected. First, a polymorphism, which generates a unique BsrI restriction site, was detected at position 2073. This BsrI polymorphism was present only in malignant keratinocytes. Second, Southern blot hybridization of PCR products revealed that there is a truncated EGFR mRNA (approximately 1.5-kb) in oral squamous cell carcinoma cell lines. Similar analysis in normal cell lines revealed that this truncated EGFR transcript is also present. Immunoblotting revealed the presence of this truncated form of EGFR in all keratinocyte cell lines. These data permit us to conclude that there exists a novel truncated form of EGFR in human oral keratinocytes. Furthermore, there exists a tumor-associated BsrI polymorphic site at position 2073. The potential biological relevance of the truncated receptor and the utility of the BsrI polymorphic site for diagnostic applications are currently being explored.

Prediction of human oral cancer radiation responsiveness by histone (H3) mRNA in situ hybridization: a preliminary report

PURPOSE

Cell cycle kinetics are believed to be a key determinant in radiation responsiveness. However, histomorphologic analysis remains an unreliable method of identifying proliferating cells. In this study, the fraction of cells undergoing division within oral cancer biopsy samples was used to predict the responsiveness of the tumor to radiation therapy.

PATIENTS AND METHODS

Eighteen cases of T1 or T2 squamous cell carcinoma of the floor of the mouth with known clinical outcomes were identified. All were treated at the Massachusetts General Hospital with external beam radiation therapy alone. The fraction of proliferating cells was determined using in situ hybridization of histone (H3) mRNA expression. Tissue viability and mRNA status was verified using in situ hybridization for beta-actin mRNA expression.

RESULTS

Matching the fraction of oral tumor cells positively labeled for histone (H3) mRNA (histone labeling index or HLI) with the actual clinical outcome showed that the HLI of radioresponsive oral tumors (12 cases) was 0.336+/-0.185 (approximately 34%+/-19%), whereas that for radioresistant oral tumors (six cases) was 0.088+/-0.078 (approximately 9%+/-7.8%). Using t-test statistical analysis for unpaired samples showed that the difference in HLI between the two groups was significantly different (P=.0068).

CONCLUSIONS

It is concluded that the use of in situ detection of histone (H3) mRNA may be a useful adjunctive criterion in the choice of treatment for human oral cancer.

Reduction of ornithine decarboxylase antizyme (ODC-Az) level in the 7,12-dimethylbenz(a)anthracene-induced hamster buccal pouch carcinogenesis model

Ornithine decarboxylase (ODC) activity is elevated in and necessary for oral carcinogenesis, but the mechanism for its deregulation is unclear. Using subtractive hybridization, a 1029 bp full-length cDNA encoding a 222 amino acid open reading frame has been isolated from normal hamster oral keratinocytes. The hamster cDNA is homologous to the human, mouse and rat ornithine decarboxylase antizyme gene (ODC-Az). The hamster ODC-Az gene demonstrated a restriction fragment length polymorphism (RFLP) upon Southern blot analysis comparing normal and tumor hamster genomic DNA. Northern blot analysis revealed that normal hamster oral keratinocytes express readily detectable level of ODC-Az mRNA. Malignant oral keratinocytes demonstrate reduced expression of the ODC-Az mRNA. In contrast, malignant hamster oral keratinocytes have elevated ODC mRNA levels and lengthened ODC protein half-life when compared to the normal counterparts. This was corroborated by direct measurement of ODC enzymatic activity. These data support the hypothesis that the reduced and/or loss of expression and function of the ODC-Az gene is an important event for the early de-regulation of cellular proliferation during oral tumor development.

Depletion of eosinophil infiltration by anti-IL-5 monoclonal antibody (TRFK-5) accelerates open skin wound epithelial closure

Wound healing is critical to the survival of the species after injury. Using hamsters as an experimental model, we have shown that eosinophils infiltrate prominently into skin wounds and that they express transforming growth factor-alpha and -beta 1 mRNAs and proteins. We hypothesized that eosinophils are important in wound healing. As no animal model is genetically deficient in eosinophils, a suitable way to test the hypothesis is to selectively reduce and/or deplete the influx of eosinophils into the wound sites. In this study, we report that anti-interleukin-5 monoclonal antibody (TRFK-5) treatment can deplete eosinophils in cutaneous healing wounds. We found that wound closure by re-epithelialization in the experimental group was 4 days faster than in the control group (P < 0.01). The density of eosinophils in day-9 wounds was significantly lower in the experimental group (P < 0.01). Wound-associated eosinophils in each of the TRFK-5-treated hamsters were depleted to the level comparable to unwounded hamster skin. These results demonstrate that anti-interleukin-5 monoclonal antibody treatment can effectively decrease eosinophil infiltration into hamster cutaneous healing wounds and indicate a role for eosinophils in negatively affecting wound re-epithelialization.

Assessment of preclinical problem-based learning versus lecture-based learning

Academic performance on a standardized oral comprehensive exam (OCE) was compared for students taught basic science in a problem-based learning (PBL) curriculum and a lecture-based learning (LBL) curriculum. The OCE was administered to the graduating classes of 1991-1994 (n approximately 20/class) six months after completion of their basic science courses. The OCE contained six components including: Organization and Thoroughness, Diagnosis, Primary Treatment Plan, Alternate Treatment Plan, Science and Medical Knowledge, and Dental Knowledge. Six to eight examiners graded each of the students by using a standardized scoring system and by subjective comments. The class of 1991 was taught by LBL, classes of 1993 and 1994 by PBL, and the class of 1992 by an incomplete PBL teaching method. Mean OCE scores were not significantly different between classes; however, the Science and Medical Knowledge component score was significantly better for the class of 1994 than for 1991 (p < 0.05). There was a non-significant 40 percent increase (p = 0.07) in honors and a 269 percent (p < 0.001) increase in cumulative positive examiner comments between 1991 and 1994.

The molecular biology of oral carcinogenesis: toward a tumor progression model

PURPOSE

An understanding of the molecular basis of oral carcinogenesis will alter our clinical approach to oral cancer. The nomenclature and major themes of molecular oral tumor biology are reviewed, beginning with the regulation events governing normal cellular physiology. In carcinogenesis, chromosomal or cytogenetic alterations lead to deregulation of tightly controlled stimulatory and inhibitory pathways, growth-promoting proto-oncogenes are mutated into overactive oncogenes, and growth-suppressing or tumor suppressor genes are inactivated. Recent advances in defining these fundamental mechanisms of tumor biology may allow prevention, diagnosis, and treatment of oral cancer to be approached at the molecular level.

Molecular biology of human oral cancer

The application of molecular biological tools to the study of cancer has significantly advanced the field of human cancer research. Such study has demonstrated the involvement of two classes of highly conserved cellular genes in the malignant transformation process: oncogenes and tumor suppressor genes. Despite these advances in the molecular biology of human cancers, our understanding of human oral cancer lags behind that of cancer of other body sites. This review attempts to assess the current status of the molecular biology of human oral cancer.

Salivary EGF regulates eosinophil-derived TGF-alpha expression in hamster oral wounds

Using hamster as an oral wound healing model, we examined eosinophils and their expression of transforming growth factor-alpha (TGF-alpha) and transforming growth factor-beta 1 (TGF-beta 1). Oral wounds healed approximately two times faster than their cutaneous counterparts. Eosinophils infiltrated prominently into oral wounds; however, unlike the dual expression of TGF-alpha and TGF-beta 1 in skin wounds, oral wound-associated eosinophils expressed TGF-beta 1, but not TGF-alpha. Because saliva is present in oral environments and contains epidermal growth factor (EGF) and TGF-alpha, sialoadenectomy was performed in this model to determine whether the lack of TGF-alpha expression by eosinophils in oral wounds is due to the presence of salivary EGF and/or TGF-alpha. We found that eosinophils in sialoadenectomized hamsters did express TGF-alpha during oral wound healing but that such expression was suppressed when EGF was added to their drinking water. Taken together, our findings suggest that eosinophil-derived TGF-alpha and salivary TGF-alpha/ EGF may have complementary roles in contributing to TGF-alpha in oral wound healing.

Deleted in oral cancer-1 (doc-1), a novel oral tumor suppressor gene

We have identified, isolated, and partially characterized doc-1, a novel cDNA sequence whose activity is consistent with a suppressor of hamster oral carcinogenesis. Doc-1 is an evolutionarily conserved gene exhibiting loss of heterozygosity and marked reduction in expression in malignant hamster oral keratinocytes. The full-length doc-1 cDNA encodes an 87 amino acid product that shows a significant homology to one of the seven novel genes induced in mouse fibroblasts by TNF-alpha. Transfection of the full-length doc-1 cDNA into malignant hamster oral keratinocytes alters the behavior of the recipients in terms of morphology, growth rate, and anchorage-independent growth, suggesting reversion of transformation phenotypes. We propose that doc-1 is a novel tumor suppressor gene in oral cancer development.

Nerve regeneration: basic and applied aspects

Increased knowledge is shedding new light on our understanding of central and peripheral nerve anatomy and molecular biology and function. New tools and methods provide important methods for the study of the behavior of cells, axons, and receptors. This review discusses the current state of that knowledge, with particular regard to the efficacy of the Seddon classification of nerve injury. The correlation of that new information to damage and repair of the peripheral sensory nerve, especially the inferior alveolar and lingual nerves, serves to highlight the progress and problems that exist.

Identification of rabbit eosinophils and heterophils in cutaneous healing wounds

The study of wound healing has traditionally used the rabbit as an experimental model. We have recently localized the production of the multifunctional cytokine, TGF-alpha, to eosinophils in rabbit skin wounds. It was evident that during the process of TGF-alpha localization, the distinction between the two granulocytic cell types, eosinophils and heterophils, was impossible by conventional histochemical techniques. This paper describes a rapid method to distinguish these two granulocytes by virtue of their endogenous peroxidases and differential resistance to blockade by inhibitors. In sections that have been blocked by hydrogen peroxide, the peroxidase substrate 3,3'-diaminobenzidine, together with nickel chloride (DAB-Ni), preferentially stained the cytoplasm of rabbit eosinophils while sparing those of heterophils. This selective DAB staining of rabbit eosinophil peroxidase in H2O2-blocked rabbit wounds was verified at the ultrastructural level by electron microscopy. We applied this technique to quantify eosinophil and heterophil infiltration into the 21-day rabbit cutaneous healing wound model. Heterophils were found infiltrated into all three layers of the wound (clot > granulation > base), but eventually all disappeared by day 21. As with the heterophils, eosinophils which had infiltrated into the clot and base of the wound had disappeared by day 21. Unlike the heterophils, eosinophils in the granulation layer of the wound continued to increase up to day 21. The continually increased and sustained presence of the eosinophils together with their demonstrated production of TGF-alpha, in the granulation layer of the healing would suggests that these cells play an important role in the organizational aspects of healing wounds.

Sequential expression of transforming growth factors alpha and beta 1 by eosinophils during cutaneous wound healing in the hamster

Transforming growth factor-alpha (TGF-alpha) and TGF-beta 1 have been proposed as important regulators of processes critical to successful wound healing. Although various cells present in wounds represent potential sources of either TGF-alpha and/or TGF-beta, including macrophages, neutrophils, keratinocytes, fibroblasts, and endothelial cells, we recently identified eosinophils as an additional potential source of these cytokines. We therefore used in situ hybridization and immunohistochemistry to determine whether eosinophils represent significant sources of TGF-alpha and/or TGF-beta 1 in skin wounds in the hamster. We found that these wounds developed a prominent infiltration of eosinophils, and that eosinophils were a cellular source of both TGF-alpha and TGF-beta 1 mRNAs. TGF-alpha and TGF-beta 1 proteins were detectable both within eosinophils and extracellularly. Moreover, there was a sequential pattern of TGF-alpha and TGF-beta 1 expression by infiltrating eosinophils, with the onset of eosinophil-associated TGF-alpha expression preceding that of TGF-beta 1. This sequential pattern of TGF expression suggests that eosinophils may help to regulate critical biological processes during wound healing.

Healing of bony defects in the irradiated and unirradiated rat mandible

A model system of the irradiated rat mandible has been developed and used in conjunction with a non-spontaneously healing mandibular defect. The contribution of the tissue components in the healing of bony defects was studied using demineralized bone powder (DBP) prepared from unirradiated or in vivo irradiated rat long bones. Better bony fill of the defects occurred in the irradiated beds filled with unirradiated DBP than in the unirradiated beds containing irradiated DBP. This suggests that, at least in the early postirradiation period, the bed is not the limiting factor in healing of bony defects and the osteogenic components of bone in the DBP may be most affected by irradiation. In the irradiated bed, the defects grafted 2 weeks after irradiation healed better than those grafted at 4 weeks. Thus, the timing of surgery after irradiation also plays a role in the healing process, with early surgery producing better results.

Restoring sensation after trigeminal nerve injury: a review of current management

After a year, even the most expert peripheral nerve repair carries a poor prognosis. Early referral and intervention offer the best management of trigeminal nerve injuries.

Critical analysis of mandibular reconstruction using AO reconstruction plates

Forty-one cases (37 patients) of mandibular reconstruction using AO plates were reviewed. The patients' ages ranged from 27 to 83 years (mean, 52.3 +/- 18.1 years) and their cases were followed for 6 to 42 months (mean, 12.7 +/- 8.3 months). Cases were grouped by the location of reconstruction: anterior mandible crossing midline as group A (12 cases), body segment of the mandible as group B (16 cases), condyle and ramus of the mandible as group C (13 cases). The incidence of revision as a measure of outcome was calculated by actuarial methods accounting for loss to follow-up or death. Revision or plate removal occurred in 22.2% (9 of 41 cases), with an incidence of 52.2% (6 of 12 cases) in group A, 12.5% (2 of 16 cases) in group B, and 7.7% (1 of 13 cases) in group C. Combined use of an AO plate and bone graft had a revision rate of 33.3% (4 of 12 cases), whereas the reconstructions with only a plate had a revision rate of 17.2% (5 of 29 cases). The difference between the immediate reconstructions (19.2%; 5 of 26 cases) and delayed reconstructions (26.7%; 4 of 15 cases) was not significant, but delayed reconstruction of the anterior mandible resulted in the highest failure rate (57.1%; 4 of 7 cases). The revision incidence was significantly higher when the area had been radiated (33.3% of 24 radiated cases and 5.7% of nonradiated cases required revision). In particular, the radiated group A had a remarkably higher failure rate (63.2% of 10 cases).(ABSTRACT TRUNCATED AT 250 WORDS)

Cellular sources of transforming growth factor-alpha in human oral cancer

Aberrant expression of TGF-alpha is associated with human malignant oral epithelium. Experiments were initiated to determine the cellular sources of transforming growth factor-alpha (TGF-alpha) in human oral cancer. Ten freshly resected human oral cancers and four specimens of normal human oral epithelium were studied by in situ hybridization and immunohistochemistry. Tissues were probed with 35S-labeled sense and antisense riboprobes to (i) human TGF-alpha (hTGF-alpha), (ii) human epidermal growth factor receptor (EGFR) to determine the distribution of TGF-alpha responsive cells, and (iii) histone H3 to examine TGF-alpha and/or EGFR's possible contribution to altered proliferation in transformed epithelium. Results of our experiments showed that TGF-alpha mRNA could be detected in normal and transformed human oral epithelium. More surprising, we have identified the major source of TGF-alpha mRNA to be the infiltrating eosinophils. A monoclonal antibody to the mature human TGF-alpha peptide stained similar areas in normal and malignant specimens. Eosinophils associated with tumors exhibited positive cytoplasmic immunostaining for TGF-alpha protein. Labeling of EGFR mRNA in human oral epithelium demonstrated uniform labeling of basal layers in normal, hyperplastic, and mildly dysplastic epithelium. In severely dysplastic epithelium and carcinomas (particularly moderate to poorly differentiated types), cellular levels of EGFR mRNA were significantly higher. The profile of altered cellular levels of EGFR mRNA correlated well with the profile of altered proliferation as indicated by H3 mRNA labeling. We hypothesize that the overproduction of EGFR mRNA in tumor epithelium--together with the localized delivery of high amounts of TGF-alpha by eosinophils at tumor-developing sites--is responsible for the increased proliferation of the tumor epithelium.

Production of transforming growth factor alpha by hamster eosinophils

Previously it was demonstrated that malignant transformation of the Syrian hamster cheek pouch mucosa is associated with the expression of TGF-alpha. Therefore in situ hybridization and immunohistochemistry was used to investigate the cellular sources of TGF-alpha production in this model system. Surprisingly one cell type in the inflammatory infiltrate present in the connective tissue adjacent to the transformed epithelium represented a major source of TGF-alpha mRNA. Detailed analysis of these cells revealed that they were eosinophils. In addition to TGF-alpha mRNA, about 40% of the eosinophils associated with the oral tumors exhibited TGF-alpha product reactive with a monoclonal antibody against the C terminus of the mature TGF-alpha peptide. Normal hamster bone marrow eosinophils also exhibited TGF-alpha mRNA and product by in situ hybridization and immunohistochemistry. These results suggest that the eosinophil represents a biologically significant source of TGF-alpha.

Electrodiagnostic evaluation of the uninjured rabbit inferior alveolar nerve

This investigation describes the electrophysiology of the uninjured rabbit inferior alveolar nerve. There were no differences in the measured waveform parameters between animals nor between the two sides of each animal. The model is reliable and could be applied to basic studies of inferior alveolar nerve regeneration and the effects of pharmacologic or surgical intervention.

Fluorescent latex microspheres as a retrograde tracer in the peripheral nervous system

Rhodamine labeled latex microspheres were used as a fluorescent retrograde tracer in the peripheral nervous system. Examination of rabbit trigeminal ganglia following application of microspheres to crushed or intact inferior alveolar nerve revealed that: (1) microspheres were taken up by only damaged axons; (2) microspheres remained in trigeminal cell bodies for up to 3 months without degradation or diffusion to extracellular structures; and (3) cells containing microspheres were capable of regenerating axons as evidenced by the return of evoked sensory action potentials and the retrograde axonal transport of True blue. Thus, fluorescent microspheres may be useful tools for in vivo survival studies of peripheral nervous system regeneration and development.

Healing of cutaneous and mucosal wounds grafted with collagen-glycosaminoglycan/silastic bilayer membranes: a preliminary report

This report describes the healing of cutaneous wounds in experimental animals grafted with collagen-glycosaminoglycan (GAG) matrix/Silastic (Dow Corning Corp., Midland, MI) bilayers; assesses the feasibility of using collagen-GAG matrix as a vehicle for delivering culture-selected, autogenous fibroblasts to cutaneous wound sites; and evaluates the use of collagen-GAG/Silastic bilayers as mucosal substitutes. Cutaneous and mucosal wounds in New Zealand white rabbits were grafted with either acellular collagen-GAG/Silastic membrane or collagen-GAG/Silastic membrane previously seeded with cultured autogenous fibroblasts. Over 63 days, wound sites were analyzed at intervals based on wound contraction and histology. Cutaneous wound successfully incorporated grafted collagen-GAG matrix and were significantly inhibited in their rate and extent of wound contraction. Seeding membrane matrices with autogenous, cultured fibroblasts before grafting caused a marked increase in cellularity that persisted throughout the postgraft period. In mucosa, matrices were exteriorized rather than incorporated. This work suggests that collagen-GAG/Silastic bilayer may have value as a dermal substitute and, more significantly, may be appropriate as a vehicle for delivering culture-selected fibroblasts to cutaneous wound sites.

The acoustical characteristics of the normal and abnormal temporomandibular joint

This paper describes the results of a clinical study that recorded and analyzed sounds emitted from the temporomandibular joint (TMJ) during simple function as a means for differentially diagnosing disorders of the joint. The technique is based on the principle that each different disorder of the TMJ produces a different effect on the mechanical relationship between the articulating surfaces of the joint, and that these mechanical effects can be determined by analyzing joint sounds in relation to joint movement. A total of 79 patients (101 joints) were studied; 32 (46 joints) were diagnosed as having extracapsular disorders, (primarily MPD), 27 (32 joints) were diagnosed as having a displaced disc with reduction, nine (10 joints) were diagnosed as having a displaced disc without reduction, and 11 (13 joints) were diagnosed as degenerative disease (osteoarthritis/arthrosis). In addition, 25 adults (50 joints) with normal TMJs were included as controls. The results of this study demonstrated that each specific disease of the TMJ is characterized by a unique relationship between the sounds propagated by the joint and the movement of the joint. Essentially, an extracapsular disease was characterized by acoustic quiescence during natural (as opposed to maximal) jaw movement, an internal derangement by a usually symmetrical short duration click/reciprocal click, or random click complex, depending on the subcategory of the disorder, and a degenerative disease by a long duration noise during either or both jaw opening and closing. The data further suggest that the technique serves to reflect the mechanical events (and abnormalities) that are involved in function of the diseased joint and has potential for use as a clinical diagnostic tool.

A clinical trial in oral surgery of the analgesic efficacy of a suprofen/codeine combination

Suprofen as well as codeine have been shown to be effective analgesics. In this study, a 200-mg suprofen/60-mg codeine dose is scored for analgesic efficacy and safety compared to suprofen (200 mg), codeine (60 mg), and placebo. One hundred sixty-five healthy, adult patients were asked to rate degree of pain experienced over a six-hour period after medication. The combination treatment was found to offer maximum pain relief. Dentists should be aware that flank pain and renal function abnormalities have been reported in postmarketing surveillance.

Free and microvascular bone grafting in the irradiated dog mandible

Microvascular and free rib grafts were placed in 4.5 cm defects in an edentate mandibular body defect 18 to 28 days after completion of 50 Gy of irradiation from a 60Co source. The animals were sacrificed from two to forty weeks postoperatively and evaluated clinically, radiographically, and histologically. There was a marked difference in the alveolar mucosal viability with the two grafts. Mucosal dehiscence was not observed over any of the microvascular grafts, but was present in seven-eighths of the free grafts. Union of the microvascular bone graft to the host bone occurred within six weeks. In contrast, after six weeks the free graft was sequestered in all the animals. An unexpected finding with both types of graft was the marked subperiosteal bone formation. This bone appeared to be derived from the host bed, stabilizing and bridging the defects bilaterally. The results suggest that radiated periosteum may play an important role in osteogenesis.

Intraoral open reduction of mandibular fractures

Experience with 31 mandibular fractures treated by intraoral open reduction techniques is reviewed and the techniques described. A 12.9% complication rate was experienced, no complication causing significant morbidity. Indications for intraoral open reduction are reviewed and the literature is discussed. The intraoral open reduction technique is a satisfactory treatment method for selected cases of fractures of the mandible.

A modified centripetal approach to parotidectomy

A modified centripetal approach to parotidectomy is reported. A total of 422 benign parotid tumors, 383 of which were primary and 39 of which were recurrent, were treated by this technique. The pleomorphic adenoma was the most common type (94.79%) in the series. Superficial parotidectomy was done in 178 cases, and total parotidectomy, in 244 cases. No permanent facial paralysis occurred after parotidectomy in the primary tumor group. Seven recurrences were observed after surgery in the recurrent tumor group.

Intraparotid hemangioma in an adult. Case report and review of the literature

We have reported a case of a vascular malformation within the parotid gland of an adult. The first symptom was acute onset of pain and swelling, consistent, in retrospect, with a thrombophlebitis and associated vascular congestion. Although the hemangioma of the parotid is not uncommon in young children, it is rare in the adult. Several clues to the diagnosis have been reviewed, all absent in the case reported. The potential confusion with primary salivary pathology is emphasized by this report.

Nerve regeneration through collagen tubes

Severe nerve injuries may require microsurgical grafting to span a defect. Introduction of graft material into a highly vascular recipient bed is documented to aid in early regeneration of neuronal blood supply. A silicone rod (SR)-induced fibrovascular sheath was employed to evaluate the regeneration of rat tibial nerve through 2-mm-diameter collagen tubes (CT) or contralateral nerve autografts (AUTO). At first operation, 5 mm of right tibial nerve was resected from 30 retired male breeder Sprague-Dawley rats. Resected nerve was replaced with either a 5 X 2 mm SR or the nerve ends were sutured to the intermuscular fascia. Four weeks later, animals were repaired by replacing the SR with either a CT or a contralateral AUTO from the left tibial nerve. Three months later, EMG testing was performed, and histologic sections were prepared. The EMG latency and the size of the compound action potential for sheathed or non-sheathed CT or AUTO were statistically superior to controls at the 95% confidence level. All other intergroup comparisons of latency and action potential size were statistically insignificant. The proportion of nerve fibers traversing the surgical sites was not influenced by the method of repair or by the presence or absence of sheathing. Tubulized repairs most closely resembled unoperated nerves, and autografted repairs had a large diameter, but much fibrosis, whereas controls displayed immaturity and disorganization. Our observations suggest that there was no difference between repairs performed with or without a vascular pseudosheath. However, CT supported regeneration better than did AUTO repair.

Glycosaminoglycans of normal and hypertrophic human scar

The glycosaminoglycan (GAG) contents of hypertrophic scars, normal scars, and human skin from cadavers of matched ages were compared. Cellulose acetate electrophoresis, chondroitinase digestions, and reaction product and infrared analyses were used to characterize the component GAGs. DEAE-cellulose chromatography was used to separate hyaluronic acid (HA) and sulfated GAGs. Chondroitinase analysis was improved under these conditions. HA was determined enzymatically. Results showed an elevation of HA in hypertrophic scar. Dermatan sulfate was the major GAG in both scars and a slightly greater quantity was observed in the hypertrophic scar. Small amounts of chondroitin 4-sulfate and chondroitin 6-sulfate disaccharide constituents were also detected by the chondroitinase assay method and these were also elevated in hypertrophic scar. These results suggest that the GAGs of hypertrophic scar differ from normal scar and normal skin.

A retrospective analysis of 327 mandibular fractures

The cases of 372 mandibular fractures are reviewed with respect to treatment, including the indications for extraction of teeth in the line of fracture, complications, and duration of maxillomandibular fixation. It was found that, in general, teeth can be maintained in the line of fracture, although there appeared to be an increased rate of complications associated with fractures when teeth are in the line of injury. In addition, a four-week period of maxillomandibular fixation appears to be an appropriate guideline for treatment.

Identification, characterization, and partial purification of mammalian skin wound hyaluronidase

A recently described mammalian wound hyaluronidase is successfully characterized and partially purified in the current study. Peak enzyme activity occurred on postwound day 7, pH optimum 4.5. Both crude and purified wound enzyme exhibited endoglycosidic activity against hyaluronate and chondroitin-4-sulfate but not against chondroitin-6-sulfate or dermatan sulfate. A 5.3-fold increase in activity was obtained by the DEAE-Sephadex purification technique described. Polyacrylamide gel electrophoresis yielded a single major band near the gel's midrange and one minor band of lesser electrophoretic mobility. These enzyme characteristics support a biochemical analogy between tissue repair in skin and numerous developmental systems and may also provide a simple means for enzymatic differentiation among chondroitin sulfate isomers.