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Biomedical subjects

R Boyd

Publications and source records attributed to R Boyd.

At least 109 records · Page 6Linked to original sources
PubMed1986

Size and filterability of human and hamster pulmonary macrophages exposed to cigarette smoke.

Pulmonary alveolar macrophages (PAM) obtained from healthy human cigarette smokers generated greater pressure in filtration through small cylindrical pores than PAM from nonsmoking controls. A well standardized hamster smoking model was employed to study the structural basis for the impaired PAM filtration accompanying cigarette smoke exposure. Hamsters also demonstrated increased PAM filtration pressure through cylindrical pores less than half a cell diameter in size after inhalation of cigarette smoke, but not after exposure to vapor phase smoke that had been strained through a particle filter. Cigarette smoker PAM were equally filterable as control through larger diameter channels, and showed comparable improvements in filterability with cytochalasin B treatment. Altered PAM filtration was associated with the formation of characteristic cytoplasmic smoker inclusions, an increase in cell size, and loss of redundant, ruffled surface membrane. The study of smoker and control PAM separated into different sizes on the basis of variations in cell density suggested that discrepancies in cell size were insufficient to explain the filtration disparity. A loss of availability of surface membrane for deformation appeared to be the most important factor responsible for the impaired filtration.

Animals↗
PubMed1986

Long-term results of chymopapain injections.

A 10- to 14-year follow-up questionnaire of 146 patients treated for sciatica from a herniated nucleus pulposus by chymopapain (Discase) injection revealed a durable, satisfactory result in 66%. In the 102 patients rated as excellent or good, 5% required surgical discectomy 50-82 months after injection. One-, two-, and three-level injections were performed and the number of levels injected did not influence the success of the procedure or the subsequent need for open surgical intervention. There was no correlation shown between the incidence of job change or unemployment and the number of levels injected.

Chymopapain↗
PubMed1985

The management of maxillo-facial injuries in vagrant alcoholics.

12 cases of serious complications of mandibular fractures in 16 vagrant alcohol-dependent patients are described. Psycho-social and metabolic factors contributed to the high frequency of infections, including osteomyelitis. The severe difficulties encountered in the treatment of patients with mandibular fractures and alcoholism are discussed.

Alcoholism↗
PubMed1984

Effects of click duration of the latency of the early evoked response.

The effect of click duration on the latency of waves I, III, and V was investigated by testing 20 normal-hearing subjects at 60 dB HL using electric pulses of 25, 50, 100, 200, and 400 microseconds. Alternating condensation and rarefaction clicks were used. The results revealed similar and nonsignificant latency differences for the 25-, 50-, and 100-microseconds pulses. However, the 100 microseconds duration is preferred to the 25-microseconds pulse because the latter reduced the maximum measurable hearing loss by about 13 dB. The results also showed that latencies increased approximately 0.10 ms as duration increased from 100 to 200 microseconds and by 0.20 ms when duration increased from 100 to 400 microseconds. Although such differences by themselves are small, they can combine with other stimulus or recording variables to be clinically significant. Therefore, it is important to control click duration when normative data are generated. A second experiment was conducted to assess the interaction of polarity (condensation, rarefaction, and alternating) and pulse duration (100 and 400 microseconds) on the wave V latency. These data revealed no latency differences among polarities at either duration.

Acoustic Stimulation↗
PubMed1983

The cultural transmission of acquired variation: effects on genetic fitness.

In a cultural species individuals acquire some aspects of their phenotypes by imitating conspecifics. Presumably, cultural transmission has some adaptive function in such species. Some authors have suggested that one such function may be the ability to transmit phenotypes that have been modified by learning or some other form of phenotypic plasticity. To examine this hypothesis we have compared the genetic fitness of cultural and noncultural individuals in three different models. In each model the environment is assumed to be variable, either in space or time, and learning modifies each individual's phenotype so as to increase the individual's fitness in the local environment. Cultural individuals transmit the modified phenotype to their offspring, while noncultural individuals do not. The models are different in the following ways: two models assume a dichotomous phenotype, one in a temporally varying environment and one in a spatially varying environment; the third model assumes a quantitative phenotype in a temporally variable environment. The two models which assume a temporally varying environment yield similar results. Genetic transmission is favored in highly autocorrelated environments while cultural transmission in environments with intermediate autocorrelation. In the spatially varying model cultural transmission is always favored.

Biological Evolution↗
PubMed1983

Chicken thrombocytes. Isolation, serological and functional characterisation using the fluorescence activated cell sorter.

Different procedures for enrichment of peripheral blood leukocytes (PBL) from whole chicken blood have been compared in terms of the percentage yield of lymphocytes and thrombocytes. The yield of thrombocytes was low in the buffy coat cells of heparinised blood, but high in PBL enriched from heparinised blood over a Ficoll-Paque density gradient and in PBL prepared from citrated blood by either technique. The fluorescence activated cell sorter (FACS) has been used to separate thrombocytes from lymphocytes in PBL by sorting of the negative cells after staining with specific anti-T and anti-B cell sera (or anti-immunoglobulin). The sorted cells were more than 99% viable, more than 98% thrombocytes by antigenic and morphological criteria and did not respond in vitro to T and B cell mitogens. Absorption studies on a turkey anti-bursa cell serum (ABST) which is cross-reactive for B cells and thrombocytes (8) indicated that the cross-reactivity is attributable to two (or more) antibody specificities in the serum rather than to one antibody directed at shared determinants on the two cell types.

Animals↗
PubMed1983

CT in pyogenic osteomyelitis of the spine.

Six patients with bacteriologically proven pyogenic osteomyelitis of the spine were followed serially with computed tomography (CT). Initial evaluation of the involved vertebral bodies and adjacent soft tissues showed a drop in CT numbers when compared to normal cancellous bone and soft tissues. A soft-tissue mass was seen in all cases. After appropriate antibiotic therapy, all six patients showed an increase in bone density and a diminution of the soft-tissue mass (p less than 0.05). Five of the six patients showed a further decrease in soft-tissue CT numbers.

Adult↗
PubMed1982

Tissue localization of lymphocyte surface antigens and receptors for immunoglobulin G Fc and complement in the chicken.

Frozen sections of chicken lymphoid organs were examined for lymphocyte surface antigens by antisera to T and B lymphocytes (ATS;ABS), and for the presence of immunoglobulin (Ig) G Fc and complement receptors (FcR;CR) by hemadsorption with sheep erythrocytes (E) coated with chicken IgG(EA), and E coated with rabbit IgG and chicken complement (EAC). In the spleen FcR positive cells were confined to the periellipsoidal sheaths and the germinal centers. CR positive cells were found in the same spleen areas, as well as in the medulla of bursal follicles. These lymphoid areas reacted strongly with ABS, but they also stained with neutral alpha-naphthyl butyrate esterase, and phagocytosed carbon particles were found in the periellipsoidal sheaths. Furthermore, in vivo treatment with cyclophosphamide, which resulted in pronounced B-lymphocyte depletion, did not affect FcR activity, but reduced CR activity significantly. These data indicate that the FcR activity demonstrated in tissue sections is mainly confined to mononuclear phagocytes, while the CR positive cells are mainly B lymphocytes.

Animals↗
PubMed1982

Characterization of pharmacy workload and pharmacist activities in a Canadian community pharmacy.

The present study was undertaken to obtain data which would characterize pharmacist activities and prescription workload in a community pharmacy. Data on pharmacist activities were obtained by using a work sampling methodology. The proportion of time spent on each of 44 activities was obtained, and it was found that the proportion of time spent on professional activities (17.6 percent) was notably less than the time spent on nonprofessional activities (82.4 percent). Data on prescription workload were obtained by the design of a data sheet which was to be completed by each pharmacist for every prescription dispensed. The collected data characterized the number of prescriptions dispensed, which were related to the time of day and day of the week; they also provided information on the types of prescriptions dispensed, the age of patients (e.g., pediatric, geriatric), and the methods of payment.

Canada↗
PubMed1981

Chicken major histocompatibility complex and disease.

The chicken MHC (B complex) initially described by Briles as controlling blood antigens, is now known to be composed of at least three regions, L, F and G. Two of these, F and G, were described on the basis of recombinants found in a study of over 10,000 chickens. On the basis of biochemical, tissue distribution and functional analyses, F corresponds to the murine H-2 K/D regions. The G region is unique to the chicken since the antigenic product is expressed only on erythrocytes and their progenitors. L was identified by serological studies and corresponds to the H-2 I region; the L antigen is expressed predominantly on B lymphocytes, monocytes and 10% of T lymphocytes, and differences in the L region result in variations in immune responsiveness. A number of functional similarities exist between the chicken MHC and that of other species such as regulation of graft rejection, graft-versus-host reaction (GVHR) and mixed lymphocyte reactions (MLR), mitogenic and immune responsiveness and resistance to RNA and DNA virus infection. The chicken MHC also controls the severity of autoimmune disease, as exemplified by the spontaneous thyroiditis of Obese strain (OS) chickens. It differs from mammalian MHC's by having of lower crossing-over frequency and no apparent gene duplication.

Animals↗
PubMed1980

Killer cells in the chicken: a microcytotoxicity assay using antigen-coated erythrocytes as targets.

A 51chromium (51Cr)release microcytotoxicity assay has been established for studying cell-mediated immunity in chickens to a potentially wide variety of antigens. The system investigated in detail uses thyroglobulin-coated chicken red blood cells (Tg-CRBC) to analyse effector cell mechanisms operative in spontaneous autoimmune thyroiditis in Obese strain (OS) chickens. A variety of technical parameters were investigated in order to optimise reliable, reproducible target cell preparation and to minimise spontaneous 51Cr-release. The final method adopted used tannic acid for coupling antigen to carefully selected donor erythrocytes of uniform MHC genotype. For the study of antibody dependent, cell-mediated cytotoxicity, Tg-CRBC were pre-sensitised with OS serum containing high titre Tg-autoantibody. Tannic acid-treated CRBC (TA-CRBC) served simultaneously as controls for the Tg specificity of direct cellular cytotoxicity (DCC) to Tg-CRBC, and also as target cells for natural, or spontaneous cellular cytotoxicity (SCC). With such an assay, cells capable of mediating Tg-specific DCC were demonstrated in the OS, but not in normal chickens. No differences in ADCC or SCC were observed when the two strains were considered as a whole, i.e. regardless of age, sex, MHC genotype or extent of disease.

Animals↗
PubMed1980

Effect of phenotypic variation on kin selection.

An expression for the equilibrium of the mean phenotypic value of a quantitative character is derived for a model in which the fitness of an individual depends on its own phenotype and the mean phenotypic value of a group of related individuals. When selection is weak the equilibrium mean is well predicted by Hamilton's k > 1/r rule (k is the ratio of mean fitness gained by recipient of altruistic behavior to mean fitness lost by donor; r is mean coefficient of relationship between donor and recipient). When selection is strong, however, the equilibrium mean depends on the heritability of the character. Low heritability can lead to substantially more "altruism" than predicted by the k > 1/r rule.

Journal Article↗