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Biomedical subjects

D R Sawyer

Publications and source records attributed to D R Sawyer.

At least 19 recordsLinked to original sources
PubMed2006

Relationship of degenerative changes of the temporomandibular joint (TMJ) with the angle of eminentia.

The purposes of this study were threefold: (i) to assess the degenerative changes of the temporomandibular joint [TMJ (condyles and articular eminence of the glenoid fossa)], (ii) to determine whether the TMJ degeneration levels differ by ethnic group and gender and (iii) to assess the association between the angles of eminentia and TMJ degeneration, while controlling for gender, ethnicity, age and number of teeth. The sample included 245 20th century dry skulls: 130 African-American (82 male and 48 female) and 115 European-American (75 male and 40 female), with a mean age of 46.4 +/- 19.9 years. The angles of eminentia were measured in a sagittal plane. The medial, central and lateral portions of the articular slope and anterior portion of the condyle were assessed for degenerative changes. Degeneration scores were calculated for the eminentia and condyles. Statistical analyses included two-way anovas, Pearson's correlation coefficients and linear regression models. There were differences in the degree of TMJ degeneration of the African-American and European-American males and females. European-American females retained fewer teeth, had the highest TMJ degeneration scores and exhibited significant relationships between the eminentia angles and degeneration. When the independent variables were entered into the regression model, only the degeneration of the eminentia was significantly associated with the angles of eminentia. Although the degeneration of the eminentia explained some of the variation of the eminentia angles, it is clear that the inclusion of multiple factors is essential to study the remodelling of the glenoid fossa.

Black or African American↗
PubMed2006

Asymmetry of the articular eminence in dentate and partially edentulous populations.

The purpose of this study was to assess the degree of right-left asymmetry of the glenoid fossa. The specific aims were (1) to determine whether there were relationships between age, number of teeth, slope of the articular eminence, fossa depth, and the degree of right-left asymmetry, and (2) to compare the right-left asymmetry of two populations, one characterized by an acceptable occlusion (A-Occ), the other by an unacceptable occlusion (partially edentulous; Un-Occ). A-Occ was defined as possessing a minimum of 28 teeth that would allow for hand articulation of the mandibular teeth to the maxillary teeth. Un-Occ had fewer than 17 teeth, which would make it impossible to articulate the mandible with the maxilla. The sample included 20th century dry skulls: 70 African-American (44 male, 26 female) and 64 European-American (49 male, 15 female), ranging in age from 21-105 (mean 47.1 +/- 19.9). The medial (M), central (C), and lateral (Lat) aspects of the right (R) and left (L) slopes of the articular eminence were measured in a sagittal plane. The R and L fossa depth also were measured. The raw absolute differences IR-LI and relative differences [IR-LI/IR+Llx100] of the articular slope angles (M, C, and Lat) and fossa depths were computed. Statistical analysis included paired t-tests, independent t-tests, and Pearson's correlation coefficients, significance at p < or = 0.05. Ninety percent (90%) of the population exhibited right-left asymmetry of the glenoid fossa. The right articular slopes (M, C, and Lat) were significantly steeper than the left articular slopes; the right fossa depths were significantly deeper than the left. There generally were no differences in the articular slope steepness or fossa depths between the partially dentate and the dentate, nor were there statistical differences between the two groups in the raw absolute differences or relative differences of the M, C, and Lat slopes or fossa depths. No significant relationships were found between right-left asymmetry, age, or number of teeth. With only 10% of the subjects exhibiting symmetry of the glenoid fossa depths or articular slope angles, clinicians should consider bilateral asymmetry the norm and not an anomaly.

Adult↗
PubMed1999

Public perception of DDS versus DMD degrees.

There are currently two degrees awarded to dental graduates from U.S. dental schools. The aim of this study was two-fold: (1) to determine the level of confusion among lay personnel concerning these degrees and (2) to identify and explore any basis for any public opinion. Five hundred and twenty-four lay persons were interviewed in Cleveland and the surrounding area. Chi-square analyses were employed to determine the effects of gender, frequency of dental visits, types of dental insurance, education level, age, income, and race on public perception of the DDS and DMD degrees. Fewer than 20% of those interviewed knew that a DDS and DMD received the same level of training. Of those who indicated there was a difference in training, 69% felt that DMDs had more training than DDSs. Since the majority of lay persons were confused about the two degrees, the establishment of one unified dental degree may contribute to a better public understanding of the education and capabilities of dentists.

Adult↗
PubMed1998

Neuregulins promote survival and growth of cardiac myocytes. Persistence of ErbB2 and ErbB4 expression in neonatal and adult ventricular myocytes.

Neuregulins (i.e. neuregulin-1 (NRG1), also called neu differentiation factor, heregulin, glial growth factor, and acetylcholine receptor-inducing activity) are known to induce growth and differentiation of epithelial, glial, neuronal, and skeletal muscle cells. Unexpectedly, mice with loss of function mutations of NRG1 or of either of two of their cognate receptors, ErbB2 and ErbB4, die during midembryogenesis due to the aborted development of myocardial trabeculae in ventricular muscle. To examine the role of NRG and their receptors in developing and postnatal myocardium, we studied the ability of a soluble NRG1 (recombinant human glial growth factor 2) to promote proliferation, survival, and growth of isolated neonatal and adult rat cardiac myocytes. Both ErbB2 and ErbB4 receptors were found to be expressed by neonatal and adult ventricular myocytes and activated by rhGGF2. rhGGF2 (30 ng/ml) provoked an approximate 2-fold increase in embryonic cardiac myocyte proliferation. rhGGF2 also promoted survival and inhibited apoptosis of subconfluent, serum-deprived myocyte primary cultures and also induced hypertrophic growth in both neonatal and adult ventricular myocytes, which was accompanied by enhanced expression of prepro-atrial natriuretic factor and skeletal alpha-actin. Moreover, NRG1 mRNA could be detected in coronary microvascular endothelial cell primary cultures prepared from adult rat ventricular muscle. NRG1 expression in these cells was increased by endothelin-1, another locally acting cardiotropic peptide within the heart. The persistent expression of both a neuregulin and its cognate receptors in the postnatal and adult heart suggests a continuing role for neuregulins in the myocardial adaption to physiologic stress or injury.

Aging↗
PubMed1998

The frequency of accessory mental foramina in four ethnic groups.

The frequency of accessory mental foramina (AMF) was studied in four population groups: 20th century Asian Indians, African Americans and American Whites, and Pre-Columbian Nazca Indians. AMF were found less frequently in the American White and Asian Indian populations than in the other groups (American White, 1.4%; Asian Indian, 1.5%; African American, 5.7% and Nazca, 9.0%). The incidence of AMFs did not differ significantly between right- and left-hand sides. In certain ethnic groups, i.e., African American, AMF may occur more often in males. Additional studies with larger samples are needed to show whether AMFs are more common in males.

Black People↗
PubMed1998

Central mucoepidermoid carcinoma.

A case of central mucoepidermoid carcinoma of the mandible is presented along with a review of the literature. The histogenesis of this tumor and the histologic similarity of the predominantly cystic low-grade central mucoepidermoid carcinoma to the glandular odontogenic cyst are discussed.

Carcinoma, Mucoepidermoid↗
PubMed1995

Styloid chain ossification: report of a case with articulations.

A bilateral ossified stylohyoid ligament was observed in a cadaver specimen. On the left side, the stylohyoid chain was markedly enlarged. The stylohyoid ligament was completely ossified into two segments separated by a diarthrodial-like joint. An articulation was also observed between the enlarged styloid process and the ossified ligament. On the right side, the styloid process had a normal appearance. The middle part of the stylohyoid ligament was ossified and it was attached to the styloid process and to the hyoid bone by a fibrous band. Proposed theories to account for the ossification of this ligament are discussed. Since the presence of an enlarged and ossified stylohyoid chain can cause much discomfort and pain, a greater understanding of the causative factors responsible for this anomaly is needed to provide for more effective diagnosis and treatment.

Humans↗
PubMed1995

Barrett's esophagus: a review.

Complications of Barrett's esophagus include ulceration, stricture, hemorrhage, perforation, and the development of malignancy. Barrett's esophagus and adenocarcinoma may be diagnosed simultaneously and that gastroesophageal reflux symptoms may be absent in many cases. Although endoscopic surveillance is justified, no agreement on the frequency can be made. Survival of patients with adenocarcinoma in Barrett's esophagus depends on the stage at diagnosis.

Adenocarcinoma↗
PubMed1992

Survey of medicinal plants used as antimalarials in the Amazon.

Plants traditionally employed for the treatment of malaria in certain areas of Brazil, where this disease is prevalent, were surveyed by interviewing natives and migrants in the Amazon Region. Forty-one plants used for malarial treatment and/or for the related symptoms (fever and liver disorders) were collected and identified. Given the potential of Brazil's forests and medicinal plants, research on traditional plant-based remedies in this country may lead to the development of new drugs.

Animals↗
PubMed1992

Oral cancer. Etiology, recognition, and management.

The cure rate for oral cancers remains dismally low at approximately 50%. The dental profession is, to a large extent, responsible for decreasing the morbidity and mortality of oral cancer even though 50% of the population do not present for routine examination and care. The dental office team must accept the charge of educating all patients concerning the devastating role of tobacco and ethanol in promoting oral cancer, as well as malignancies at other sites. Dental clinicians play a vital role on the oral cancer team. Therefore, they must make themselves well aware of the diverse nature of oral cancer and must have an appropriate triage protocol in place so that lesions will be identified and managed correctly or referred promptly to the correct tertiary health care professionals. Early detection and prompt proper management can make a difference as we await the development of new and better ways of treating oral and oropharyngeal cancers.

Adult↗
PubMed1991

Retromolar foramen: a mandibular variant important to dentistry.

The retromolar foramen (RMF) was found to occur in eighteen of 234 adult human mandibles studied (7.7%). No statistically significant difference was found between left and right sides or between sexes. A statistical correlation was made between the occurrence of the RMF and accessory mandibular foramina, accessory mental foramina, mandibular third molars, and three-rooted mandibular first molars. Only the accessory mandibular foramen showed a significant positive correlation with RMF regarding same-side occurrence. Three-rooted first molars were not found in any of the mandibles studied. Due to the relatively frequent occurrence of RMF, it is important for the dental practitioner to be aware of this variant and the possible complications which may occur during the administration of anesthesia and surgical procedures in the region.

Adult↗
PubMed1990

Mylohyoid and jugular foramen bridging in pre-Columbian Chileans.

The occurrence of mylohyoid groove bridging and jugular foramen bridging was determined in a population of adult Pre-Columbian Chileans. Two hundred forty-one crania (110 males, 131 females) were examined for jugular foramen bridging and 464 mandibles (252 males and 212 females) were observed for mylohyoid groove bridging. The overall incidence of jugular foramen bridging was 14.94%, with females showing a higher occurrence (18.32%) than males (10.91%); however, no statistical significance was found between the sexes. The right side showed a greater incidence than the left, but again no statistical difference was noted and the occurrence of this trait was found to be associated between the sides. This frequency of jugular foramen bridging is higher than that found in other studies and approaches that reported in North American Eskimo populations. In the case of mylohyoid groove bridging, the incidence was 4.09% with no difference found between the sexes. This frequency of occurrence is less than the values reported previously for the other American populations of Mongoloid ancestry including the Pre-Columbian Peruvian population. The importance of nonmetric skeletal traits for defining population groups and their usefulness as anthropological tools is discussed. It is concluded that hard tissue variations such as bony bridging may be reliable markers to aid in discretely identifying population groups, but their importance can be significantly enhanced by coupling as many traits as possible in future studies.

Asian People↗
PubMed1990

An ancient "tumour" from pre-Columbian Chile.

A case of an expansile facial lesion discovered in the more than 600 years old skeletal remains of a 22-25-year-old female is discussed. Gross, radiographic and histological studies were accomplished on the specimen. Although a definitive diagnosis could not be derived because of the age and condition of the specimen, differential diagnoses are discussed and a probable diagnosis rendered.

Adult↗
PubMed1988

A condylar tumor from pre-Columbian Chile: a case report.

A case of an expansile, multilocular lesion in a condyle recovered in skeletal remains more than 700 years old is discussed. Gross, radiologic, and histologic studies were accomplished on the specimen. Although a definitive diagnosis could not be arrived at because of the age of the specimen, differential diagnoses are presented.

Adult↗