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Biomedical subjects

M Edgerton

Publications and source records attributed to M Edgerton.

26 records · Page 2Linked to original sources
PubMed1991

Location of abnormalities in panoramic radiographs of edentulous patients.

A series of 308 panoramic radiographs of edentulous patients was examined for the presence of pathoses to determine whether any predictive basis could be found for occurrence of abnormalities by sex, age, or location. Radiolucencies, radiopacities, and retained roots and teeth were recorded by size and by anterior or posterior location in edentulous jaws. Radiopacities were the most frequently found abnormality (18% of subjects), followed by retained roots (8%), radiolucencies (3%), and retained teeth (3%). No significant correlation was found by chi-square test between type or location of abnormality and sex of the patient. There was, however, a significant relationship between location and type of abnormality. Radiopaque and radiolucent lesions were more frequently found in the mandible, and unerupted teeth and retained roots were more frequently seen in the posterior maxilla. Selective radiographs to detect retained roots and unerupted teeth in the posterior maxilla may be most productive in terms of prosthodontic treatment outcome. Otherwise, this study finds no basis for selection of intraoral sites for specific intraoral radiographs of asymptomatic edentulous patients.

Aged↗
PubMed1990

Salivary histatin 5: dependence of sequence, chain length, and helical conformation for candidacidal activity.

Histatin 5 (Asp1-Ser-His-Ala4-Lys-Arg-His-His8-Gly-Tyr-Lys-Arg12-Lys-Ph e-His-Glu16-Lys-His - His-Ser20-His-Arg-Gly-Tyr24), one of the basic histidine-rich peptides present in human parotid saliva and several of its fragments, 1-16 (N16), 9-24 (C16), 11-24 (C14), 13-24 (C12), 15-24 (C10), and 7-16 (M10), were synthesized by solid-phase procedures. Native histatin 5 from human parotid saliva was also purified. Their antifungal activities on two strains of Candida albicans have been studied and their conformational preferences both in aqueous and non-aqueous solutions examined by circular dichroism. The synthetic histatin 5, C16, and C14 peptides were highly active and inhibited the growth of C. albicans. The candidacidal activity data of synthetic histatin 5 were comparable to the values of the native histatin 5 isolated from parotid saliva and those reported previously, although the assay system used and the strains examined were different. The C16 fragment was as active as the whole peptide itself, whereas the N16 fragment was far less active than C14, suggesting that the sequence at the C-terminal is important for its fungicidal activity. An increase in the chain length of the C-terminal sequence from 12 to 16 residues increased the candidacidal activity, thereby indicating that a peptide chain length of at least 12 residues is necessary to elicit optimum biological activity. The CD spectra of these linear peptides showed that they are structurally more flexible, and they adopt different conformations depending on the solvent environment. CD studies provided evidence that histatin 5 and the longer fragments, C16, N16, and C14 preferred alpha-helical conformations in non-aqueous solvents such as trifluoroethanol and methanol, while in water and pH 7.4 phosphate buffers, they favored random coil structures. The shorter sequences seemed to adopt either turn structures or unordered structures both in aqueous and non-aqueous solutions. It appears that the sequence at the C-terminal of histatin 5 with a minimum chain length of 14 residues and alpha-helical conformation are the important structural requirements for appreciable candidacidal activity.

Amino Acid Sequence↗
PubMed1987

Maternal prenatal, infancy and concurrent predictors of maternal reports of child psychopathology.

RESEARCH on parent perceptions of infant temperament and child maladjustment has evolved from an initial interpretation of parent reports as objective, veridical descriptions of the child to an interpretation of parent reports as social perceptions that reflect both objective qualities of children and personality characteristics of parents (Bates 1983). Evidence that parents' descriptions reflect generalized behavior of their children is provided by modest correlations between parent and teacher reports of child behavior (Becker and Krug 1964; Glidewell et al. 1959; Rutter et al. 1970). Although limited agreement of parents and teachers in descriptions of child behavior might be interpreted as evidence of situational specificity of behavior (Mischel 1968), an alternative interpretation is that characteristics of parents influence their perceptions of child behavior. This longitudinal study tests hypotheses that maternal characteristics during pregnancy and infancy, prior to the development of stable child characteristics, predict mothers' reports of child psychopathology during the kindergarten year.

Child↗
PubMed1975

The lack of effect of cyclic adenosine 3':5'-monophosphate on Avena coleoptile growth.

The effects of cyclic adenosine 3':5'-monophosphate (cAMP) on the growth of Avena coleoptile segments over 4 to 10 hours were monitored with a position sensing transducer. At pH 6, cAMP (0.1 mm with and without 2.5 mm glucose; or 2 mm alone) or dibutyryl cAMP (0.1 mm) was added at the beginning of the experiment, or after about 1 hour or after about 6 or 7 hours. Under all conditions tested, cAMP compounds had little or no effect on coleoptile segment elongation. Inasmuch as cAMP does not duplicate the rapid and vigorous elongation obtained with 2 mum auxin, the hypothesis that cAMP is a mediator of auxin activity is not supported by experimental evidence in this system. This conclusion is dependent upon the assumption that the cAMP compounds penetrated the tissue.

Journal Article↗
PubMedDate not supplied

Evaluation of the clinical predictability of hydroxyapatite-coated endosseous dental implants: a review of the literature.

Although the use of hydroxyapatite-coated (HA-coated) endosseous implants in the treatment of dental patients has been established, their clinical predictability remains controversial. This study is an analysis of the clinical predictability and indications for use of HA-coated endosseous implants. This study also discusses the biochemical composition of commercial HA coatings in relation to in vivo predictability, potential concerns, and potential advantages of HA coatings. Clinical studies suggest that HA-coated implants have short-term survival rates (ranging from 6 months to 6 years) that are comparable to short-term survival rates of titanium implants. In addition, clinical data suggest that HA-coated implants may be valuable treatment modalities when placing implants (1) in type IV bone, (2) in fresh extraction sites, (3) in grafted maxillary and/or nasal sinuses, or (4) when using shorter implants (less than or equal to 10 mm). However, long-term controlled studies are required to validate these observations.

Alveolar Bone Loss↗
PubMedDate not supplied

Experimental salivary pellicles formed on titanium surfaces mediate adhesion of streptococci.

The goal of this study was to characterize salivary components of titanium pellicles and to determine how experimental pellicles affect adhesion of several strains of streptococci to titanium surfaces. Titanium experimental pellicles were formed by incubation of fresh human parotid or human submandibular-sublingual saliva on pure titanium beads. Pellicle was recovered from the beads using sodium dodecyl sulfate buffer and was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting to identify adsorbed salivary components. Streptococcus anginosus, S. oralis, and S. salivarius recovered from in vivo titanium plaque and five reference strains of streptococci were used in adhesion assays to titanium beads with and without experimental salivary pellicles. The experimental pellicle formed on titanium was found to be composed of selected proteins from human parotid and human submandibular-sublingual saliva. Salivary alpha-amylase and proline-rich proteins were found in all experimental pellicles, while sIgA, high-molecular weight mucin, and proline-rich glycoproteins were detected in one of the experimental pellicles examined. Adhesion of fresh isolates and reference stains of S. anginosus, S. oralis, and S. salivarius to saliva-coated titanium was reduced compared to that of titanium without saliva coating. However, adhesion of laboratory strains of S. gordonii and S. sanguis was found to be significantly greater to experimental pellicles of human submandibular-sublingual saliva than was the adhesion of the fresh isolates, suggesting that streptococci-colonizing implant surfaces may be inherently less adhesive than other bacterial strains. This study found that salivary pellicles are selectively formed on titanium and mediate in vitro adhesion of streptococci.

Adsorption↗