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Biomedical subjects

M Barnard

Publications and source records attributed to M Barnard.

54 records · Page 3Linked to original sources
PubMed1990

An ethnographic study of HIV-related risk practices among Glasgow rent boys and their clients: report of a pilot study.

This paper provides an early report of a continuing ethnographic study of male prostitution in Glasgow. Pilot work indicates that rent boy activity may be of considerable importance for the spread of HIV infection. Although there is little evidence of an association between rent boy activity and injecting drug use, rent boys may well be implicated in epidemic spread because many (but not all) of them report unsafe sexual practices. Some boys reported that they engaged in unprotected anal sex both actively (insertor) and passively (insertee). Although the majority of the boys' clients were covert bisexuals--married men seeking occasional, anonymous, male sexual contact--a substantial minority of clients were gay-identified.

Adolescent↗
PubMed1990

Adolescents, sex and injecting drug use: risks for HIV infection.

In this paper we present data on the HIV-related risks for adolescents growing up in an area where injecting drug use is prevalent and HIV infection has been identified among local injecting drug users. We report on young peoples' knowledge, attitudes and perceptions of drug use and injectors; HIV and AIDS; sex, safer sex and condom use. These adolescents had an extensive and practically oriented knowledge of illicit drugs and drug injectors. The majority of adolescents contacted had an unsophisticated but approximate understanding of HIV transmission dynamics and how to guard against infection. Our data suggest that many adolescents find issues relating to sex awkward, embarrassing and difficult subjects for discussion. In a final section we consider some of the policy implications of our work focussing in particular on the prevention of injecting, the promotion of condom use, and the necessity of avoiding a focus upon risk groups.

Adolescent↗
PubMed1990

Injecting drug use and female street-working prostitution in Glasgow.

There are considerable difficulties associated with calculating the prevalence of covert, illegal and stigmatized activities. This paper outlines new methods we have developed for calculating the prevalence of both drug-injecting street prostitution and non-injecting street prostitution in Glasgow. Our data indicate that Glasgow has a much higher level of injecting drug use than has been reported among prostitutes in other British cities.

Female↗
PubMed1989

HIV-related risk behaviour among a non-clinic sample of injecting drug users.

This paper focuses upon HIV-related risk behaviour among a sample of injecting drug users purchasing injecting equipment at a retail pharmacy in Glasgow. It is shown that the majority of the individuals interviewed were concerned about HIV/AIDS and that many were optimistic about their chances of avoiding contracting the virus. However, it is shown that the shared use of injecting equipment was continuing and that many individuals were prepared to provide their own injecting equipment to others, even if they were unprepared to re-use it again themselves. We also consider here the possibility of encouraging drug injectors to switch to non-injecting drug use and the potential basis for any sexual transmission between drug injectors and others. The paper concludes with a consideration of some of the policy implications of this work.

Adolescent↗
PubMed1988

Clonal rearrangement of the T-cell receptor gamma gene associated with a bizarre lymphoproliferative syndrome.

Investigations in an unusual patient with prolonged fever, fat necrosis and haemorrhagic tendency showed widespread histiocytic phagocytosis in fat and liver biopsy specimens. Lymph nodes were also infiltrated by morphologically normal T lymphocytes predominantly expressing the OKT4 antigen. Analysis of lymph node DNA using immunoglobulin and T-cell receptor (TCR) probes showed rearrangement restricted to the gamma TCR gene combined with polyclonal beta TCR gene rearrangements, thus providing evidence of a unique lymphoproliferative disorder of T cells. The patient displayed a striking response to cytotoxic chemotherapy.

DNA↗
PubMed1986

Polysaccharide surface antigens expressed by nonmucoid isolates of Pseudomonas aeruginosa from cystic fibrosis patients.

We tested nonmucoid Pseudomonas aeruginosa isolates obtained from cystic fibrosis (CF) patients for the expression of lipopolysaccharide (LPS) serotype antigens, serum sensitivity, and production of mucoid exopolysaccharide (MEP). When all nonmucoid isolates were compared with a set of random mucoid isolates, 20 of 52 (38%) nonmucoid isolates were typable and serum resistant, compared with 13 of 51 (24%) mucoid isolates (P = 0.16 by chi-square analysis). However, nonmucoid strains from CF patients colonized only with nonmucoid strains were more frequently typable and serum resistant (67%) than were nonmucoid isolates from patients cocolonized with mucoid strains (31%) (P = 0.012, Fisher exact test). An inhibition enzyme-linked immunosorbent assay done with bacterial extracts, a direct-whole-cell enzyme-linked immunosorbent assay done with affinity-purified antibody to MEP, and immune electron microscopy all demonstrated production of MEP by all nonmucoid P. aeruginosa isolates tested, including nonmucoid revertants of mucoid strains. No other bacterial species tested positive in these assays. These findings suggest that MEP is produced by all P. aeruginosa isolates obtained from CF patients, that the initial colonizing nonmucoid strains produce a smooth LPS, and that once LPS-rough, mucoid strains appear in the sputum, the predominant LPS phenotype is rough regardless of colony morphology.

Antigens, Bacterial↗
PubMed1985

Effects of peptidoglycans from periodontal pathogens on selected biological activities of CD-1 murine peritoneal macrophages.

Resident CD-1 murine peritoneal macrophages were exposed to various concentrations of purified peptidoglycan isolated from members of the genera Bacteroides, Eikenella, and Actinomyces. Macrophage viability, the release of lysozyme, acid phosphatase, and prostaglandins E1 and E2 were assayed as a function of peptidoglycan concentration and time. Macrophages responded as a function of peptidoglycan concentration with increased release of acid phosphatase and prostaglandins; all cells remained greater than 90% viable during the course of the experiments. However, concentrations of peptidoglycan greater than 50 micrograms/mL were toxic to the macrophages, while the peptidoglycan from B. capillus strain 925.08 and Actinomyces viscosus strain T14AV consumed complement by both the classical and the alternate pathways. Cellular lysozyme activity and phagocytosis of Saccharomyces cerevisiae were significantly reduced in the presence of peptidoglycan. When viewed by scanning electron microscopy, the activated macrophages were rounded, lacked distinct pseudopod extensions, and possessed an increased number of microvilli and plasma membrane associated vesicles. These morphological alterations occurred as early as 3 h. Transmission electron microscopy revealed the purified peptidoglycan to have been taken up into numerous phagosomes; however, even after 24 h incubation, it was only partially degraded.

Acid Phosphatase↗
PubMed1980

Difference infrared spectroscopy of aqueous model and biological membranes using an infrared data station.

A Perkin-Elmer infrared Data Station associated with a simple IR spectrometer (model 298) is shown to give excellent results with aqueous model and biomembrane systems. Examples are presented of difference spectra obtained with lipid--water systems, reconstituted lipid--protein systems and a natural biomembrane. The spectra of the lipid after water subtraction and of the intrinsic protein after lipid subtraction from a model reconstituted Ca2+-ATPase membrane system are shown. The potential for studying intrinsic protein conformations is emphasised.

Animals↗
PubMedDate not supplied

Use of multicolor spectral karyotyping in genetic analysis of pleuropulmonary blastoma.

Pleuropulmonary blastoma (PPB) is a rare, malignant intrathoracic pediatric tumor. It arises from the lung, pleura, or mediastinum and its pathogenesis and relationship to other pediatric solid tumors is not well understood. In this study, a case of PPB in a 3-year-old girl was studied using a combination of molecular genetic methods and cytogenetics. Molecular analysis of the commonly encountered fusion translocation gene products of pediatric solid tumors failed to detect a rearrangement. Cytogenetic analysis, supplemented by multicolor spectral karyotyping (SKY), identified an unbalanced translocation between chromosomes 1 and X, resulting in additional copies of 1q, an extra copy of Xq, and loss of part of Xp. In addition, trisomy 8 was detected. The identification of new chromosomal alterations and confirmation of previously reported ones in this rare neoplasm helps to improve our understanding of its pathogenesis and association with other pediatric tumors.

Child, Preschool↗
PubMedDate not supplied

Angiomyolipoma: immunohistochemical and ultrastructural study of 14 cases.

Angiomyolipoma (AML) is a mesenchymal neoplasm of unclear histogenesis. In addition to varying amounts of smooth muscle, adipose tissue, and blood vessels, it contains a population of clear or pale eosinophilic epithelioid cells often arranged around blood vessels. Various phenotypes of AML have been described: leiomyoma-like, lipoma-like, epithelioid, and atypical. AMLs show consistent immunopositivity for HMB-45. This has been associated with the ultrastructural observation of melanosome-like structures in rare instances. In the present study, 14 AMLs from 13 patients were analyzed by electron microscopy and immunohistochemistry to determine the appearance and nature of cells composing AMLs. Overlap between cell types (spindle smooth muscle cells, epithelioid cells, and adipocytes) was found by both electron microscopy and immunohistochemistry. Melanosomes were found in 7 tumors. The cell of origin remains mysterious. Nevertheless, the study demonstrates that the AML is likely derived from a single cell that shares homology with the pericyte.

Adult↗
PubMedDate not supplied

Evaluation and correction for a 'training effect' in the cognitive assessment of older adults.

BACKGROUND: Repeated administration of psychometric instruments frequently results in a higher score on retesting, the so-called training effect. Yet, a training effect has been poorly considered in longitudinal studies of cognitive changes in older persons. METHODS: We investigated the presence, magnitude and potential adjustments for training effect in the older participants of the Systolic Hypertension in the Elderly Program (SHEP). SHEP evaluated the cognitive status effects of a diuretic-based treatment of isolated systolic hypertension versus placebo. Changes in the short Comprehensive Assessment and Referral Evaluation (short-CARE) questionnaire score, from baseline through 4 years of follow-up, were assessed in 4,718 participants. In this study, we used two regression techniques to adjust data for the training effect. RESULTS: In both study groups, a training effect was evident as a progressive improvement in the short-CARE score throughout year 1. Thereafter, cognitive scores tended to deteriorate, more in the placebo than in the active treatment group (p = 0.055). When follow-up scores were adjusted based upon baseline data, the difference between the study groups reached statistical significance (p = 0.019), but the apparent overall trend towards deterioration in cognitive score was no longer observed. Adjustment of baseline data preserved this apparent temporal course, but did not improve the discrimination between the two study groups (p = 0.165). CONCLUSIONS: In SHEP, repeated cognitive assessments were likely biased by a training effect which could be only partially corrected by statistical techniques. Studies of changes in the cognitive status of older persons should be designed appropriately to estimate and minimize the consequences of a training effect in follow-up data.

Aged↗
PubMedDate not supplied

Continuous spinal anesthesia: dose requirements and characteristics of the block.

BACKGROUND AND OBJECTIVES: A fine-bore 28G CoSpan spinal catheter was used to provide continuous spinal anesthesia for major upper and lower abdominal, peripheral vascular, and orthopedic surgery in 90 patients, aged 31-91 years. METHODS: Initial doses (0.5-2.0 mL) of hyperbaric bupivacaine 0.5% were given and followed, if needed, by additional doses of 0.5-1.0 mL to achieve a satisfactory blockade for the proposed type of surgery. The incidence of hypotension, ambulatory postdural puncture headache, and technical problems encountered with insertion of the spinal catheters were recorded. RESULTS: The technique of continuous spinal anesthesia was successful and easy to learn. Satisfactory sensory and motor blockade was achieved within 12-18 minutes, and surprisingly small amounts were needed in those patients undergoing limb surgery. CONCLUSIONS: Mild postdural puncture headache occurred in four patients, but none of the patients required blood patch. One catheter broke during removal; since then, it has been our policy to remove a catheter with the patient in a flexed position.

Abdomen↗