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Biomedical subjects

J Adam

Publications and source records attributed to J Adam.

At least 73 records · Page 4Linked to original sources
PubMed1986

Assessing cultured colonies automatically.

The number of colonies formed by macrophage colony-forming cells and high proliferation potential colony-forming cells was assessed by an image processor. The processor counted and sized colonies accurately, reproducibly, rapidly (2 s/dish) and objectively. The processor also measured the amount of light (in grey levels) the colonies transmitted. The optical density of a colony (the sum of its grey levels) was related to its cellularity. Thus the image processor compared both the number of colonies in samples and their cellularity. Samples of marrow containing high proliferation potential colony-forming cells of different proliferative capacity were prepared by injecting fluorouracil into mice and collecting their marrow 2-10 days later (marrow samples called FU2-FU10). These samples were cultured with one of three sources of synergistic factor titrated over seven dilutions. Colonies contained approx. 5 X 10(4) cells after 11 days culture but the way that FU2-FU10 marrow grew depended on the interval between treating donors with fluorouracil and collecting their marrow. Samples collected 2-4 days after fluorouracil formed more colonies containing more cells with small increases of synergistic factor whereas samples collected after 8-10 days did neither. It was important to culture samples of marrow with the appropriate synergistic factor for the interval after fluorouracil. Factor(s) derived from the 5637 cell line acted optimally on high proliferation potential colony-forming cells in samples collected 2-8 days after fluorouracil, and factor(s) derived from Wehi 3B cells on high proliferation potential colony-forming cells in samples collected 6-10 days after fluorouracil. Factor(s) derived from placental conditioned medium acted well on samples collected between 2 and 10 days. The proliferative capacity of samples of marrow could also be compared by estimating growth curves for high proliferation potential colony-forming cells in samples collected at successive intervals after fluorouracil.

Animals↗
PubMed1985

What does a trainee see?

The experience of a trainee was documented in detail for a complete training year and the data were stored and analysed using a suite of purpose-written computer programs. The results indicate that the experience of the trainee was extremely similar to that of the trainer and that continuity of care must be considered in planning a training programme. The findings also emphasize that general practice deals with a wide range of problems many of which occur infrequently and therefore may not be adequately covered during the training year.

Continuity of Patient Care↗
PubMed1984

Assessment of adequacy of pancreatic enzyme replacement with the multiple-phase carbon-14-triolein test.

The carbon-14-triolein absorption test was used to investigate fat absorption and its response to pancreatic enzyme replacement therapy in 10 men with pancreatic steatorrhoea. Absorption was increased in all, from 1,14 +/- 1,2% of the dose per hour (group mean +/- SD) to 2,85 +/- 2,33% (P less than 0,01) by the simultaneous administration of 8 tablets of enteric-coated pancreatic enzymes (Nutrizym; Merck). In patients with normal or high gastric acid secretion, neutralization of gastric acid with 30 ml magnesium trisilicate had no effect on absorption while the addition of an extract of gastric secretions (Enzynorm; Noristan) to the therapy of the 1 achlorhydric patient improved absorption from 2,2% to 3,81%. The 14C fat test offers a rapid and more acceptable alternative method for determining individual response to pancreatic enzyme replacement therapy than the conventional 72-hour faecal fat excretion measurement. The enteric-coated pancreatin preparation used in this study appears to be optimally effective under conditions of normal gastric acid secretion.

Adult↗
PubMed1984

Haemopoiesis by clonal succession?

Alloenzymes of phosphoglycerate kinase (Pgk-1A and 1B), an X-linked enzyme of the glycolytic pathway that is expressed on all somatic cells, were used to study properties of developmentally early haemopoietic cells of mice (high proliferation potential colony-forming cells, HPP CFC) This study showed that: The colonies formed by HPP CFC are clones; There are distinct populations of HPP CFC that can respond to different haemopoietic growth factors; There are substantial differences in the proportions of Pgk alloenzymes of similar sets of HPP CFC found in similar and neighbouring bones; and In the whole animal, there is no evidence of any single population of HPP CFC that is permanently derived from a limited set of precursors.

Animals↗
PubMed1983

A correlational analysis of symmetry between the arrowhead and featherhead Müller-Lyer illusions.

Correlational methods were used to investigate symmetry of effect for the arrowhead and featherhead versions of the Müller-Lyer figure. Two control figures were compared in the determination of baseline levels for measurement of the illusions: a shaft presented without any inducing context, and a shaft with vertical inducing lines attached. In addition, results based on difference-score measures of the illusions were contrasted with results obtained by partial-correlation techniques. Overall, when one considers the results for either one of the arrowhead or featherhead versions, the evidence favours a common underlying mechanism. However, results across the two versions suggest that the mechanisms for the two versions differ fundamentally. In weighting the different kinds of evidence contributing to this conclusion, methodological issues were raised. By obtaining two judgments for each stimulus figure from a large number of subjects, it was possible to demonstrate not only that conventional difference-score measures of illusions are highly unreliable, but also that they can yield biased results.

Adolescent↗
PubMed1983

Seasonal variations of carbon monoxide-induced polycythemia in rats.

Fluctuations of the extent of polycythemia in rats due to repeated exposure to carbon monoxide prompted us to study whether the differences were caused by seasonal variations. Data from 18 independent experiments involving the hemoglobin values of 206 CO-exposed and 208 control rats over a period of nearly 3 years were available. Because the experiments were not designed for chronobiological studies, several methods of quasilinear and nonlinear regression analysis were applied to fit periodic models to the data. The best fit was obtained by a single cosine function with a period of nearly 12 months and with maximum values in winter and minimum values in summer. Experiments to elucidate mechanism(s) of seasonal variations showed that following a single CO exposure to the nocturnally active rodents, the rate of CO release from the body was higher in the dark span, that reduced food supply produced a potentiation of the CO-induced hemoglobin increase, and that the adaptive CO response was not affected by testosterone or thyroidectomy, but inhibited by L-thyroxine. Thus it seems that influences of light, CO elimination rate, food intake, metabolic rate and related hormones play a role for seasonal variations.

Animals↗
PubMed1982

Familial cerebral amyloidosis and spongiform encephalopathy.

Clinical and neuropathological investigations are presented of the "W" family in which there is a dominant inheritance of slowly progressive cerebellar ataxia and dementia. The disease is of insidious onset and its average duration more than 4 years. Pathological findings included amyloid deposition in cerebellar and cerebral tissue; vascular amyloid in one case; and spongiform encephalopathy and astrocytic hyperplasia typical of Creutzfeldt-Jakob disease. Neuritic plaques of the senile (Alzheimer) type were present to a lesser extent. This study confirms the familial association between cerebral amyloidosis and spongiform encephalopathy.

Adult↗
PubMed1980

Control stimuli in investigations of the acute-angled and obtuse-angled Müller-Lyer illusions.

Over the past decade, attention has been drawn to the importance of intertip distance (the distance between the tips of the arrowheads or featherheads) as a possible determinant of the Müller-Lyer illusion. Investigation of this stimulus property for the arrowhead and featherhead components of the Müller-Lyer figure has indicated that the two components exhibit a lack of symmetry, a conclusion supported by other studies using rather different approaches to the investigation of symmetry. This article argues that the control stimuli used in previous investigations are inadequate. It is proposed that in addition to the conventional straight-line control stimulus, in which the standard shaft is stripped of the oblique inducing lines. H-shaped figures in which the inducing lines are vertical should be included. Results are reported of an experiment in which both types of control stimuli are used to investigate the effects of intertip distance, and the spatial separation of that distance from the standard shaft, upon the arrowhead and featherhead figures.

Adult↗