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Biomedical subjects

K A McLean

Publications and source records attributed to K A McLean.

At least 37 records · Page 2Linked to original sources
PubMed1993

Myopathy in HIV infection: the role of zidovudine and the significance of tubuloreticular inclusions.

Muscle biopsies were obtained from 33 consecutive HIV-infected patients with symptoms suggestive of muscle disorder. Twenty-three patients had clinical evidence of myopathy; 18 of these had been taking zidovudine (AZT) for between 8 and 28 months, and were found to have a multifocal necrotizing myopathy with little or no inflammation. However, the remaining five clinically myopathic patients, who had never received AZT or had stopped treatment at least 5 months earlier, had either a necrotizing myopathy which appeared indistinguishable for that seen in patients taking the drug, or an inflammatory myopathy. The 10 clinically non-myopathic patients showed no significant histological abnormalities. Tubuloreticular inclusions (TRI), in capillary endothelial cells, were found in all clinically myopathic cases but were not seen in five out of ten clinically non-myopathic cases. We suggest that AZT causes a myopathy only when an underlying HIV-related inflammatory myopathy is present. The drug appears to substantially reduce the inflammatory reaction in the muscle, but this may recur when the drug is stopped. The appearance of TRI may be the first manifestation of HIV activity in muscle.

Adult↗
PubMed1993

Subcutaneous versus intravenous administration of heparin in the treatment of deep vein thrombosis; which do patients prefer? A randomized cross-over study.

Patient preference for intravenous or subcutaneous heparin in the treatment of deep venous thrombosis was assessed in a randomized cross-over study. Twenty patients with venographically proven deep venous thrombosis were randomized to receive subcutaneous or intravenous heparin for 3 days followed by 3 days of the other treatment. Discomfort at the injection site, assessed by visual analogue scale, was significantly less for the subcutaneous than the intravenous administration route (P < 0.001), mobility was thought to be better when receiving subcutaneous heparin (P < 0.005) and patients' overall preference was for subcutaneous treatment (P < 0.001).

Adult↗
PubMed1992

Influence of age on plasma osmolality: a community study.

We have shown an age-associated increase in plasma osmolality (p less than 0.001) in 152 randomly selected subjects, living in the community. In the old [mean age 78.0 (7.5) years] the plasma osmolality was 302.2 (300.6-303.8) mOsmol/kg compared with 291.2 (290.0-292.3) mOsmol/kg in the young [39.2 (11.2) years] (p less than 0.0001). In a further group of 20 screened, health status defined, elderly subjects the plasma osmolality was 298.1 (295.9-300.3) mOsmol/kg, which was significantly higher than the young group (p less than 0.0001) but lower than the unscreened old subjects (p = 0.005). The variance was also significantly lower (p = 0.03). The results may reflect a loosening of homoeostatic control and highlight the need for care in subject selection in studies of ageing.

Adult↗
PubMed1992

Water homeostasis and ageing.

The elderly are at risk of developing disturbances of water homeostasis, and clinicians have to rely on laboratory measurement to determine their presence and magnitude. Optimum management depends on having a clear understanding of age-associated changes in water homeostasis. Many studies have flawed methodology, but some conclusions can be drawn. There is a diminished thirst, but the relationship of plasma osmolality to arginine vasopressin is at least preserved, and may show increased responsiveness. There is reduced renal function with age and the kidneys' ability to produce a concentrated urine declines. Similarly, the excretion of a water load becomes impaired. Further study is needed of the interaction of specific diseases with these age-associated changes.

Aged↗
PubMed1991

Acute rheumatic fever in human immunodeficiency virus infection.

A 25-year-old homosexual man with a childhood history of rheumatic heart disease presented with painful joints, fever and chest pain. He was diagnosed as having acute rheumatic fever and was found to be HIV antibody-positive. His illness responded to conventional treatment but he had a persistently low CD4 lymphocyte count and was started on zidovudine. Interpretation of the significance of a low CD4 lymphocyte count is problematic in a patient with coincident rheumatic fever and HIV infection as both conditions can cause CD4 lymphopenia.

Acute Disease↗
PubMed1991

A simple and rapid method for detecting human immunodeficiency virus by PCR.

A simple, sensitive and specific method using the polymerase chain reaction (PCR) for amplification of human immunodeficiency virus type 1 (HIV-1) is described. The method involves minimal manipulations. Peripheral blood mononuclear cells (PBMC) were prepared by a rapid Ficoll-Paque gradient method. Lymphocytes were lysed in PCR buffer containing Proteinase K and detergents, and subjected to amplification under stringent conditions, using two primer pairs. Amplified DNA sequences were hybridized with a 3'-end labelled probe, electrophoresed on agarose gels and visualised by ethidium bromide staining. Identification of amplified HIV-1 proviral DNA sequences was confirmed by autoradiography. HIV-1 sequences were amplified in all samples from 103 HIV-1 seropositive individuals, but not in 40 HIV-1 seronegative controls. The absence of contamination may be attributable in part to minimisation of manipulations before amplification.

Base Sequence↗
PubMed1990

Preliminary report: accurate assays for anti-HIV in urine.

Untreated urine specimens from 358 patients (344 attending genito-urinary medicine clinics, 14 haemophiliacs) and 353 blood donors were tested blind by a simple IgG-capture particle-adherence test (GACPAT) and a rapid IgG-capture enzyme-linked immunosorbent assay (GACELISA) for antibody to human immunodeficiency virus (anti-HIV). All 158 urine specimens from seropositive subjects were anti-HIV positive by GACPAT and 157 of them (99.4%) were positive by GACELISA. Tests on 553 urine specimens from seronegative subjects gave two repeatable false-positive reactions by GACPAT (0.4%) and none by GACELISA. By means of a modified procedure anti-gp160 was detected by commercial western blot in the urine of 44 of 45 seropositive subjects examined. IgG-capture assays will detect anti-HIV in unconcentrated urine and so allow a diagnosis in circumstances when blood sampling is impracticable.

Blotting, Western↗
PubMed1990

Cultivation of human immunodeficiency virus from whole blood: effect of anticoagulant and inoculum size on virus growth.

Human immunodeficiency virus (HIV) was cultivated directly from whole blood treated with anticoagulant by cocultivation with phytohaemagglutinin-stimulated cord blood lymphocytes. When heparin was used as the anticoagulant, isolation rates were low (10% to 56%, depending on the patient group); but when EDTA was used, isolation rates were much higher (50% to 100%). Culture of whole blood gave results identical to those of culture of separated peripheral mononuclear cells, and in some cases virus could be isolated from as little as 10 microliters of unseparated EDTA anticoagulated blood.

Adult↗
PubMed1990

Reduced survival with increasing plasma osmolality in elderly continuing-care patients.

The results reported here are from a 2-year follow-up study of 58 elderly patients in a continuing-care unit. Most of these patients were in a hyperosmolar state at the time of entry (mean plasma osmolality 304 +/- 8 mOsmol/kg). The survival of those patients with the highest osmolality (greater than 308 mOsmol/kg) was significantly reduced (p = 0.025), with an increased mortality at 2 years (15/20 patients, p = 0.053). There was no correlation between age and plasma osmolality (r = 0.02) and the effect of osmolality on survival was independent of age. Hyperosmolality was either a marker for, or a cause of, increased mortality in this group of frail elderly patients.

Aged↗
PubMed1989

Trends in sexual behaviour and risk factors for HIV infection among homosexual men, 1984-7.

To assess whether the spread of infection with HIV can be reduced by changes in behaviour among groups most at risk because of their sexual practices sexual behaviour was monitored among 1050 homosexual men tested for HIV infection at a genitourinary medicine clinic in west London from November 1984 to September 1987. Four cohorts, defined by date of presentation, were studied by questionnaire at their presentation, and blood samples were analysed. Between the first and last cohorts there was a considerable fall in the proportion reporting casual relationships (291/329 (88%) v 107/213 (50%] and high risk activities, such as anoreceptive intercourse with casual partners (262/291 (90%) v 74/106 (70%], with the greatest changes occurring before the government information campaign began in 1986. Nevertheless, half of the men in the last cohort studied reported having casual partners. Multiple logistic regression showed that behavioural risk factors for HIV infection most closely resembled those for hepatitis B and that previous sexually transmitted diseases (syphilis, hepatitis B, and anogenital herpes) were themselves independent risk factors. A history of syphilis ranked above anoreceptive intercourse as the strongest predictor of HIV infection. Actively bisexual men showed a much lower prevalence of HIV infection (3/57, 5%) than exclusively homosexual men (113/375, 30%). Sexual behaviour among homosexual men changed during the period studied, and the incidence of HIV infection fell, although more education programmes directed at homosexual men are needed to re-emphasise the dangers of infection.

AIDS Serodiagnosis↗
PubMed1989

Transmission of HIV to heterosexual partners of infected men and women.

Future heterosexual spread of HIV will in part depend on the efficiency of transmission from men to women and from women to men. We studied seventy-eight female sexual partners of men infected with HIV and 18 male sexual partners of infected women. Participants were interviewed concerning sexual practices, use of contraception and other risk factors for HIV infection. Fifteen out of 78 (19.2%) female partners and one out of eighteen (5.5%) male partners were seropositive for HIV antibody. All couples had practised vaginal intercourse. Seropositive female partners did not differ significantly from seronegative partners with regard to length of relationship, number of acts of vaginal intercourse, other sexual practices, stage of clinical disease in the index case, or numbers of other sexual partners in the last five years. In two women, seroconversion was documented after one act of unprotected sexual intercourse. The majority of infected female partners (eight out of 15) had sexual relationships with men who were asymptomatic and did not practice anal intercourse. Biological factors such as variability in infectivity of the index case and susceptibility of the contact, as well as behavioural variables may be important in determining transmission.

Adolescent↗