PubMed Health⌕ Search

Biomedical subjects

M Davies

Publications and source records attributed to M Davies.

At least 487 records · Page 27Linked to original sources
PubMed1981

Variations in the intensity of BCG-potentiated alloimmune anti-tumor responses: the differential stimulation of T-cell subpopulations.

The interexperimental variation often observed following the repeated monitoring of immune phenomenon was analysed using the alloimmune cellular response that developed in the spleens of B6AF mice following a challenge with Mastocytoma P815-X2 and intervention with BCG. The response, mediated solely by T cells, could be defined in terms of the involvement of nylon-wool adherent and nonadherent T cells. The relative contribution of each cell type to the response was found to vary considerably and could be use to define the interexperimental variation. Hence when a given treatment resulted in a poor response, the major contributors were nonadherent to nylon-wool, while when the same treatment yielded a good response, adherent cells became the predominant contributors. It was concluded that the inter-experiment variations observed here were a biological event, rather than an experimental artefact, being a function of the relative contribution of different T-cell subpopulations.

Adjuvants, Immunologic↗
PubMed1981

The effect preloads of amino acid on shortterm satiety.

The effect of a preload of an amino acid preparation on food intake in man was assessed in eight subjects. Each subject was given a small dose of amino acids or placebo 1/2 h before being presented with a meal. This was done in a blind, randomized fashion on five occasions for each preparation to each subject. The mean food intake of the subjects when receiving the amino acid preparation was 10% (p less than 0.01) less than the intake when receiving the placebo. When the subjects were grouped according to their variation from ideal weight, a 22.5% reduction in food intake was observed in group I (n = 4) who were greater than 5% above the ideal weight for height ratio (p less than 0.001). A 1.75% increase (NS) was seen in group II (n = 4) whose weight was within 5% of their ideal weight. These results demonstrate a modulation of satiety by small caloric doses of amino acids in overweight subjects.

Amino Acids↗
PubMed1981

Addison's disease presenting as a hypercalcemic crisis in a patient with idiopathic hypoparathyroidism.

A patient with idiopathic hypoparathyroidism complicated by Addison's disease is described. The development of adrenal insufficiency was accompanied by a hypercalcaemic crisis. The hypercalcaemia appeared to result from a reduction in the filtered load and enhanced renal tubular reabsorption of calcium. Cortisone therapy was followed by the characteristic renal tubular leak of calcium associated with hypoparathyroidism and a return of the serum calcium to normal. The possible mechanisms for these changes in calcium homeostasis are discussed.

Addison Disease↗
PubMed1981

Primary hyperparathyroidism and thiazide diuretics.

Six patients receiving thiazide diuretics were referred for evaluation of mild to moderate hypercalcaemia (serum calcium 2.65-2.98 mmol/l). All patients were considered to be suffering from primary hyperparathyroidism. Withdrawal of the diuretic was followed by a reduction in the serum calcium, one patient becoming normocalcaemia. The mechanisms responsible for these changes are discussed. In hypercalcaemic patients taking thiazides, it is recommended that the effects of withholding the diuretic should be observed before more radical measures are considered.

Aged↗
PubMed1981

Examination of different preparations of human placental plasma membrane for the binding of insulin, transferrin and immunoglobulins.

Plasma membrane was prepared from human placental tissue by two standard methods. The preparations, termed PVM and PPM, examined by electron microscopy and polyacrylamide gel electrophoresis, were characterized with respect to their binding properties for insulin, transferrin, alpha 2-macroglobulin and the immunoglobulins, IgM and IgG1. By means of sucrose density-gradient centrifugation, it was possible to fractionate the PVM into two distinct fractions. The first fraction, under the conditions used, was heavier (density greater than 1.080 g . cm-3) and was obtained as a pellet. It bound transferrin and IgM and had low specific activities for 5'-nucleotidase and for the binding of IgG1. The lighter fraction (density range 1.048-1.050 g . cm-3) had a high specific activity for 5'-nucleotidase and for IgG1 binding. Transferrin and IgM did not bind to this fraction. Insulin bound to both the fractions with comparable levels of specific binding activity, while alpha 2-macroglobulin binding was undetectable. The PPM preparation was found to have binding properties similar to those of the light fraction of PVM.

Cell Fractionation↗
PubMed1981

Prepubertal endogenous major depressives hyposecrete growth hormone in response to insulin-induced hypoglycemia.

Insulin tolerance tests (ITT) were carried out during illness in 27 drug-free prepubertal children with emotional disorders: 10 fit unmodified Research Diagnostic Criteria (RDC) for major depressive disorder endogenous subtype, 10 fit RDC for nonendogenous major depressive disorder, and 7 fit DSM-III criteria for nondepressed neurotic disorders. The endogenous depressed group hyposecreted growth hormone (GH) in this test as compared to the other groups. Since GH hyposecretion in response to ITT is a characteristic of adult endogenous depressives, the data support the validity of the diagnosis of prepubertal endogenous major depressive disorder and the hypothesis of similarity of prepubertal and adult major depressions.

Blood Glucose↗
PubMed1980

Reflections on a cytology screening service.

A review of the results of the examination of gynaecological material undertaken during one year by an established cytology laboratory taking part in the Population Screening Service for Carcinoma of the Cervix in the United Kingdom is presented. The overall positive rate was 5/1,000 and for first examinations was 9.4/1,000. Only a relatively small proportion of the female population was screened but this included a wider spread over the social classes and a greater number of younger women, in whom the disease is becoming more common. In view of the failure to involve all women in a comprehensive screening programme, it is considered advisable to concentrate on those women who are particularly at risk and to take advantage of their attending family planning, ante-natal and veneral disease clinics where cervical smears can be taken, even if they are below the age of 35 years at which the screening programme usually starts. Training in cytology for doctors and nurses working in the clinics is essential and the availability of a special cytology clinic to assist in the diagnosis of difficult cases is very valuable.

Adolescent↗
PubMed1980

Clinical monitoring of intracranial pressure in fulminant hepatic failure.

Cerebral oedema is the commonest immediate cause of death in fulminant hepatic failure and an investigation was carried out to determine the value of monitoring intracranial pressure (ICP) and to examine the effects of ICP of dexamethasone therapy and mannitol administration. ICP values in 10 patients at the time of insertion of a subdural pressure transducer (grade IV encephalopathy) averaged 15.5 +/- SD 14.8 mmHg. Despite dexamethansone therapy, which had been started on admission, rises in ICP were subsequently observed in seven of the eight patients who died. In the two patients who survived, the highest reading were 47 and 35 mmHg. Mannitol consistently reversed or arrested ICP rises when pressure was < 60 mmHg. ICP monitoring provides additional information in the managment of patients and is essential if mannitol therapy is to be used.

Adolescent↗
PubMed1980

Comparative absorption of vitamin D3 and 25-hydroxyvitamin D3 in intestinal disease.

The absorption of simultaneously administered equimolar doses of 14C vitamin D3 and 3H 25 hydroxyvitamin D3 (25-OH-D3) has been studied in controls and patients with a variety of gastrointestinal disorders. As assessed from peak radioactivity in the serum and from faecal excretion of radioactivity, malabsorption of both vitamin D3 and 25-OH-D3 occurred in patients with steatorrhoea. Malabsorption of vitamin D3 was greater than 25-OH-D3. The magnitude of malabsorption of these compounds was related to the severity of the steatorrhoea but was moderate enough to suggest that replacement therapy in patients with intestinal malabsorption should be accomplished with relatively small doses of vitamin D. The more potent vitamin D metabolites are probably unnecessary in this situation.

Adult↗
PubMed1980

Glomerular basement membrane injury by neutrophil and monocyte neutral proteinases.

Human peripheral blood leucocytes known to be present in the glomeruli of patients with certain forms of clinical glomerulonephritis have been investigated for their proteinase content and their ability to degrade glomerular basement membrane (GBM). Polymorphonuclear leucocytes (PMN) and monocytes, but not lymphocytes, contain neutral proteinases which extensively degrade GBM at physiological pH. Inhibitor studies indicate that the enzymes responsible are serine-type proteinases. The relative susceptibilities of the GBM to proteolytic attack showed that the monocyte preparation was considerably more active than the PMN neutral proteinases. The monocyte preparation also showed the ability to degrade GBM at acid pH. Lymphocytes had no effect on GBM either at acid or neutral pH. The possibility that the lysosomal proteinase of monocytes and PMNs are implicated in the damage to the GBM in glomerulonephritis is suggested.

Basement Membrane↗
PubMed1980

The binding of human lysosomal elastase to glomerular basement membrane.

The interaction of purified elastase with glomerular basement membrane and its antigens was studied. There appears to be at least two types of interaction. The first is a weak interaction and the enzyme can be removed simply by extended washing with neutral buffer. The second, stronger interaction is desorbed with high salt concentration at alkaline pH. The different interactions probably represent the binding of isoenzymes. Further experiments demonstrate that all isoenzymes degrade the membrane. Serum proteins prevent binding and inhibit the action of elastase on glomerular basement membrane.

Basement Membrane↗
PubMed1980

Evidence that kidney lysosomal proteinases degrade the collagen of glomerular basement membrane.

Three thiol-dependent tissue proteinases have been isolated from human kidney cortex by methods using detergent extraction, gel chromatography, affinity chromatography and separation by ion-exchange. The properties of each enzyme toward several chromogenic low molecular weight substrates, azocasein and collagen indicate that they are similar to cathepsins B, H and L. All three enzymes degrade glomerular basement membrane at acid pH. Cathepsin B and L were particularly active against glomerular basement membrane. It has been demonstrated that in liver these enzymes exist together in lysosomes. These properties indicate that the kidney thiol proteinases may be an important factor in the turnover of glomerular basement membrane.

Basement Membrane↗