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Biomedical subjects

R Knight

Publications and source records attributed to R Knight.

53 records · Page 3Linked to original sources

The use of Ferastral in iron-deficient, non-pregnant Gambian adults.

A new parenteral iron preparation, iron-poly (sorbitol-gluconic acid) complex, (Ferastral) has been evaluated in the treatment of iron-deficient, non-pregnant Gambian adults. A total of twenty patients of both sexes were included in the study. The cause of anaemia in the majority of cases was hookworm infection but also other diagnostic categories were present. Sixteen patients completed their treatment without difficulty. All patients showed a good initial haematological response. Over the first three weeks the mean daily increments followed a linear trend. There was a significant inverse correlation between initial haemoglobin concentration and the increment in concentration after three weeks treatment. Side-effects were noted in four patients; in two patients it was ascribed to treatment, in two there was concurrent infection. Parenteral iron therapy is considered to have definite advantages over oral iron in the tropics because of certainty of administration, replenishment of iron stores, and effectiveness when small bowel disease or dietary factors reduce absorption.

Adolescent

Transfer factor: hypoxanthine is a major component of a fraction with in vivo activity.

Transfer factor was prepared from the leukocyte lysates of four donors with known skin test reactivity. After ultrafiltration and double-gel filtration on polyacrylamide gels, fraction IV of the preparation was found to have biologic activity. This fraction contained one major and occasionally one minor ultraviolet-absorbing and zero to one ninhydrin-detectable spots on thin-layer chromatography. The major ultraviolet spot was identified as hypoxanthine. Hypoxanthine was demonstrated to be responsible for the high 260 nm/280 nm ratio of preparations with biologic activity in vivo. It was not determined if hypoxanthine is required for transfer factor activity. In addition, an orcinol-negative preparation also had biologic activity.

Chromatography, Thin Layer

Cellular requirements for simulation by the purified streptococcal antigen DSR.

Delayed skin reactor (DSR) was prepared from streptokinase-streptodornase. Peripheral blood mononuclear cells, were collected from a Ficoll-Hypaque gradient and subsequently subdivided into T cell-, B cell-, or monocyte-depleted populations. Mononuclear cells with complement receptors (B cells) were removed by a nylon-wool column adsorption. Sheep erythrocyte rosette forming cells (T cells) were removed by centrifugation on a second gradient. Populations of cells which did not adhere to plastic and/or ingest iron filings were monocyte-depleted. While response to DSR as measured by incorporation of tritiated thymidine into DNA was not affected by removing B lymphocytes, it was significantly diminished by removing T lymphocytes. Monocyte-depleted cells incorporated less tritiated thymidine into DNA in both antigen stimulated and control cells, but the stimulation index was not significantly altered.

Antigens

Endocrine studies in a phenotypic girl with XY gonadal agenesis.

An 18-year-old phenotypic girl with XY gonadal agenesis had endocrine studies. The patient had a small amount of sexual hair, a slightly enlarged clitoris, normal labia and no posterior fusion. Her vagina was of normal length, but no cervix was palpable. At laparoscopy, no gonads, uterus or fallopian tubes were identified. The buccal smear was chromatin negative and the karyotype was 46XY. The 24 h LH plasma pattern was qualitatively similar to that found in normal late pubertal subjects, but the values were in the castrate range. The 24h mean plasma concentrations of testosterone and dihydrotestosterone were 16.4 ng/dl and 14.2 ng/dl, respectively. Urinary estrogen excretion was 15 and 19 mug/day. These clinical and endocrine findings suggest that the patient was a genetic male in whom Mullerian regression occurred normally; however, the testes probably ceased functioning early in gestation preventing normal development of the Wolffian system. This set of events resulted in agenesis of the gonaductal system and female external genitalia. The patient represents the second example of this variation of male pseudohermaphroditism associated with XY gonadal agenesis.

Adolescent

Disturbed preschizophrenics. Childhood symptoms in relation to adult outcome.

Adult outcome information was obtained for a sample of 45 males with a hospital diagnosis of schizophrenia. All cases had been treated at a child guidance clinic as children prior to the onset of schizophrenia as young adults. Refined outcome categories, which reflected the independent judgments of two clinical raters, led to the comparison of poor outcome with more favorable outcome cases in terms of antecedent characteristics. Five rationally derived childhood symptom scales were used. The psychotic scale was significantly related to poor outcome, while acting-out and aggressive symptom scales were related to more favorable adult outcomes. Neurotic and neurological scales were not predictive of outcome. Low childhood IQ and poor peer adjustment were significantly related to poor adult outcome. Sample limitations and comparison with results from other studies were discussed.

Adolescent

Surveys for amoebiasis; interpretation of data and their implications.

In survey work, stool microscopy for cysts and serology are the only really practicable measures of amoebic infection. The diagnostic sensitivity of stool microscopy should be estimated. Using a simple deterministic mathematical model, the rates of gain and loss of infection and seropositivity may be estimated from survey data. The low value of the constants creates difficulties but they can be estimated from: (1) cumulative data from frequently sampled cohorts; (2) analysis of the curves of age prevalence; (3) analysis of curves of long-term follow-up studies. The second method is the simplest and normally gives valid results. Appropriate epidemiological studies can give useful information about protective immunity, incubation period, superinfection, and interactions between amoebic infection and various host factors, including other disease states. Knowledge of the rate constants of infection allows predictions to be made about the likely effect of control measures.

Age Factors

Fine structural changes at Entamoeba histolytica rabbit kidney cell (RK 13) interface.

When bacteria-free trophozoites of Entamoeba histolytica were added to a monolayer of rabbit kidney cells, cellular injury occurred at the sites of contact. Changes appeared within the cell cytoplasm before there was any generalized cell membrane damage. At some points of contact there was apparent fusion of amoebic and cell cytoplasm. Electron-dense bodies, here interpreted as liposomes, were present in the amoebic cytoplasm and beneath the surface membrane. No surface lysosomes were seen. Various modes of cell damage and enzyme transfer from amoeba to cell are suggested, together with the possibility that cytopathic amoebae are infected with virus particles.

Amebiasis

The choice of practice location.

A ten per cent sample survey of all general practitioners in England and Wales in 1969-70 included two questions about the choice of practice location. The most common reasons given were the absence of any real alternatives (in the immediate post-war period), the influence of family or friends, the existence of medical contacts in the area, and favourable points about the practice itself.In considering possible future moves, general practitioners would pay closest attention to the educational facilities of an area, its rural or coastal location, its social and cultural amenities, and the practice conditions. The conclusion is drawn that financial incentives are unlikely to contribute much towards a more equal distribution of general-practitioner manpower. More thought should be given to recruitment to the medical profession in under-doctored areas through the development of the highest professional standards and facilities in such places.

Adult