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Biomedical subjects

R Oliver

Publications and source records attributed to R Oliver.

At least 55 records · Page 3Linked to original sources
PubMed1993

The topographic distribution of brain atrophy in Huntington's disease and progressive supranuclear palsy.

The topographic distribution of brain atrophy was quantified by image analysis of fixed coronal brain slices from 12 patients dying with Huntington's disease (HD) and from 4 other patients dying with progressive supranuclear palsy (PSP). In HD, atrophy was maximal within the caudate nucleus, putamen and globus pallidus. However, the cerebral cortex was also atrophied with reductions in cross-sectional area within frontal, temporal and parietal lobes. In general, more white matter than grey matter was lost leading to an elevation in the grey/white matter ratio. The amygdala and thalamus were reduced in area. In PSP, lesser reductions in cortical area than those of HD were seen, these again being mostly due to a loss of white matter, resulting in an elevation of the grey/white ratio. The globus pallidus and thalamus were decreased in area, but no changes in the caudate nucleus and putamen were measured.

Adult↗
PubMed1993

Development of the Safety Assessment of Function and the Environment for Rehabilitation (SAFER) tool.

Increasing numbers of seniors are choosing to remain in the community; however statistics for in-home accidents indicate that the over-65 age group is at the greatest risk. The purpose of this article is to describe the Safety Assessment of Function and the Environment for Rehabilitation (SAFER) Tool, which was developed by occupational therapists to address the need for a comprehensive functional and environmental assessment tool to be used with the elderly in the community. It consists of 15 areas of concern arranged in a logical and sensitive manner, subdivided into 128 items or functions. All items must be addressed and if appropriate, checked off as a problem. The tool fulfills the requirements of being quick and easy to use and on completion, it provides clear directions for intervention and treatment.

Accidents, Home↗
PubMed1992

Health of the nation.

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Community Mental Health Services↗
PubMed1992

Minocycline slow-release formulation effect on subgingival bacteria.

The purpose of this study was to determine the microbiological efficacy of an adjunctive minocycline periodontal formulation delivered subgingivally. Subjects were systemically healthy but exhibited severe periodontitis; i.e., probing depths greater than 6 mm. The two study groups included individuals who received minocycline or a placebo periodontal formulation after root planing. Subgingival plaque samples were obtained at baseline; prior to treatment; and at 1, 3, and 6 months. Plaque was evaluated by darkfield microscopy and further analyzed for total dark-pigmented Bacteroides species, P. intermedia, P. gingivalis and Streptococcus, Actinomyces, Eikenella, Actinobacillus, Capnocytophaga, and Fusobacterium species using cultivable flora techniques. In addition, plaque was evaluated for yeast on a selective agar medium. When compared to the placebo, the minocycline group had significantly lower proportions of spirochetes at 1 and 3 months and lower proportions of motile rods at 3 months. Furthermore, when compared to the placebo group, the minocycline patients had lower mean proportions of dark-pigmented Bacteroides spp. and P. intermedia at 1 and 3 months as well as lower proportions of E. corrodens at 1 month. The minocycline group had significant decreases in proportions of spirochetes at 1 and 3 months, motile rods at 1 and 3 months, and increases in cocci at 1, 3, and 6 months when compared to baseline. In the placebo group, root planing was also effective at decreasing spirochetes at 1, 3, and 6 months, but with significant differences seen only at 3 and 6 months. However, the degree of reduction in spirochete proportions was greater in the minocycline group when compared with the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomyces↗
PubMed1991

Orthodontic bonding using glass ionomer cement: an in vitro study.

The aim of this study was to investigate the in vitro 24-hour tensile/peel bond strength of glass ionomer cement (GIC) together with the amount of cement left attached to the enamel surface after bond failure. The effect of contamination with moisture during setting/hardening and changing the powder/liquid mixing ratio of the GIC was also studied. Five GIC's (Intact, Fuji II, Orthocem B, ChemFil II, and Ketac Fil[capsulated]) and one composite resin (Concise) were tested by bonding GAC eyelets, with a curved photo-etched base, to the buccal surface of human premolars. Bond strength testing was performed on an Instron 1185 testing machine and the amount of cement left attached to the enamel surface quantified using the ARI index. The tensile/peel bond strengths achieved with all the GIC's were significantly lower than the composite resin (P less than 0.0002). Increasing the powder/liquid ratio resulted, in general, in higher bond strengths, the increase being significant for Intact and Orthocem B (P less than 0.05). Protection from moisture did not significantly affect the bond strength with the exception of Fuji II, for which, there was a significant decrease when the material was mixed at the recommended powder/liquid ratio.

Acrylic Resins↗
PubMed1990

Heterogeneity in tumor microvascular response to radiation.

Viable hypoxic cells have reduced radiosensitivity and could be a potential cause for treatment failure with radiotherapy. The process of reoxygenation, which may occur after radiation exposure, could increase the probability for control. However, incomplete or insufficient reoxygenation may still be a potential cause for local treatment failure. One mechanism that has been thought to be responsible for reoxygenation is an increase in vascular prominence after radiation. However, the effect is known to be heterogeneous. In this study, tumor microvascular hemodynamics and morphologies were studied using the R3230 Ac mammary adenocarcinoma transplanted in a dorsal flap window chamber of the Fischer-344 rat. Measurements were made before and after (at 24 and 72 hr) 5-Gy radiation exposure to assess microvascular changes and to explore possible explanations for the heterogeneity of the effect. There was considerable heterogeneity between tumors prior to radiation. Vascular densities ranged from 67 to 3000 vessels/mm3 and median vessel diameters from 22 to 85 microns. Pretreatment perfusion values varied by a factor of six. In irradiated tumors, conjoint increases in both vascular density and perfusion occurred in most tumors, although the degree of change was variable from one individual to the next. The degree of change in density was inversely related to median pretreatment diameter. Relative change in flow, as predicted by morphometric measurements, overestimated observed changes in flow measured hemodynamically. These results support that heterogeneity in tumor vascular effects from radiation are somewhat dependent on pretreatment morphology as well as relative change in morphology. Since changes in flow could not be completely explained by morphometric measurements, however, it is likely that radiation induced changes in pressure and/or viscosity contribute to the overall effect. Further work in this laboratory will investigate these hypotheses.

Adenocarcinoma↗
PubMed1989

Morphologic and hemodynamic comparison of tumor and healing normal tissue microvasculature.

The purpose of this study was to compare microvascular morphometric and hemodynamic characteristics of a tumor and granulating normal tissue to develop quantitative data that could be used to predict microvascular characteristics which would be most likely associated with hypoxia. The dorsal flap window chamber of the Fisher 344 rat was used to visualize the microvasculature of 10 granulating and 12 tumor (R3230 AC adenocarcinoma) tissues at 2 weeks following surgical implantation of the chamber. Morphometric measurements were made from photomontages and video techniques were used to assess red cell velocities in individual vessels. The percent vascular volume of both tissues was close to 20%, but significant differences were noted in other morphometric and hemodynamic measurements. Individual vessel dimensions (length and diameter) in tumors averaged twice as large as those in granulating tissues. Furthermore, red cell velocities were twice as high in tumors as in granulating tissues. In addition to these large differences in average values, there was significant heterogeneity in tumor microvascular morphometry, indicating spatial nonuniformity compared with the granulating tissue. Approximations of vessel spacing, indicated an average of 257 and 118 microns in tumors and granulating tissues, respectively. Vessel densities were four times greater in granulating tissues than in tumor tissues. These results indicated that intervessel distances were more likely to result in hypoxia in tumors, especially considering the wide variability in that tissue. Analysis of flow branching patterns showed that vascular shunts occurred frequently in vessels ranging from 10 to 90 microns in diameter. The results of this study indicate, in this tumor model, that conditions such as low vascular density, vascular shunts, excessive vascular length and/or low red cell velocity exist to a greater extent than the granulating tissue control. These conditions are likely to be conductive to the development of hypoxia.

Adenocarcinoma↗
PubMed1987

Infection of cattle by airborne foot-and-mouth disease virus: minimal doses with O1 and SAT 2 strains.

Equipment has been constructed and methods developed for exposing individual cattle to two strains of foot-and-mouth disease (FMD) virus in aerosols to determine the minimal infective dose by the respiratory route. The aerosols used were produced either artificially by a spinning-top aerosol generator, in which case they were of homogeneous small particle size (less than 3 micron in diameter) or else they were derived naturally from infected pigs, in which case the particles were heterogeneous in size. Two strains of FMD virus were used: an O1 strain of UK origin and a SAT 2 strain from South Africa. The lowest doses which initiated infection were 12.5 TCID50 of O1 BFS virus and 25 TCID50 of SAT 2 virus, infectivity having been assayed in primary bovine thyroid cell cultures. Following exposure to low doses of virus (range 12 to 316 TCID50) 33 per cent of the cattle exposed to O1 BFS virus and 27 per cent exposed to SAT 2 virus were infected but did not develop detectable vesicular lesions.

Aerosols↗
PubMed1986

Legal liability of students and residents in the health care setting.

Legal liability of students and residents in the health care setting can have significant consequences for clinical faculty members, the health care facility, and the educational institution. Parties involved in educating students and residents in the health professions, therefore, should have a clear understanding of potential liabilities and well defined procedures to minimize such risks. In this article, the author examines issues and significant court cases related to the liability of students and residents in the health care setting.

Education, Medical↗
PubMed1984

Cross-national reliability study of a schedule for assessing personality disorders.

The inter-rater reliability of a schedule used to assess personality disorders was examined. The Personality Assessment Schedule (PAS) involves an interview with both the patient and a close informant and the ratings for the informant are given most weight in the final scoring. Videotaped interviews with 23 psychiatric patients, most of whom had a clinical diagnosis of personality disorder, and a close informant were scored by seven raters, four in the United Kingdom and three in the United States. Overall inter-rater reliabilities (using the intraclass correlation coefficient, RI) were generally good to excellent for each of the 24 personality variables tested, ranging between .66 and .94 for informants and between .51 and .91 for subjects. Corresponding reliability coefficients for overall mean PAS scores were .82 and .75, respectively. Consistent with these findings, there was little bias between the scores of American and British raters, although there was some tendency for American raters to score higher for the trait of eccentricity and lower for the trait of conscientiousness than was true for British raters. There was less bias for informants' ratings than for those of subjects. In a second set of analyses, it was shown that inter-rater reliability levels (using the Kappa statistic) were also good to excellent (.6 to .8) for the categorical diagnosis of personality disorder. These results, taken together, demonstrate that abnormal personality can be reliably assessed by both British and American raters.

Adolescent↗
PubMed1982

The dandruff story.

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Dermatitis, Seborrheic↗