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Biomedical subjects

V Marks

Publications and source records attributed to V Marks.

At least 289 records · Page 16Linked to original sources

A radioimmunoassay method for prednisolone: comparison with the competitive protein binding method.

Cross reactivity of prednisolone with an antiserum raised against dexamethasone-21-hemisuccinate conjugated with bovine serum albumin was utilized to develop a radioimmunoassay for prednisolone in unextracted plasma. The results are in good agreement with those obtained with a standard competitive protein binding method employing prior extraction and separation of the synthetic from endogenous steroids.

Humans↗

Hypothalamic-pituitary function following successful treatment of intracranial tumours.

Hypothalamic-pituitary function was examined in seventeen patients treated in the past for extrasellar intracranial tumours. All patients had received a course of external cranial irradiation. Biochemical abnormalities of endocrine function were present in almost all of the patients. In particular, the growth hormone response to insulin induced hypoglycaemic stress was impaired in eleven out of fifteen patients. Preliminary data from a group of seven patients with intracranial tumours prior to radiotherapy are also presented. The possibility that cranial irradiation causes hypothalamic-pituitary dysfunction is discussed. The results suggest that endocrine assessment should be considered in patients who have been treated for intracranial tumours, even in the absence of direct pituitary involvement.

17-Hydroxycorticosteroids↗

The effect of some polyene macrolides on absorption from the small intestine in the rat.

The effect of three polyene macrolides, candicidin, amphotericin B and nystatin on the absorption of [3H] cholesterol was studied in the rat by using the in situ gut loop perfusion technique. Chronic treatment with candicidin and its presence at various concentrations in the gut loop perfusion experiments inhibited [3H] cholesterol absorption although a smaller effect was also obtained with amphotericin B and nystatin at higher concentrations. A similar but much less pronounced action of candicidin was also observed on the absorption of [3H] corticosterone and [14C] phenytoin.

Amphotericin B↗

Haemoglobin changes, diet and anthropometric measurements in adolescent male detainees.

A fall in haemoglobin noted in detainees in a Detention Centre in 1972 prompted a more detailed study to find possible reasons for this change. A significant fall in haemoglobin occurred between the first and third day after arrival, and no further fall had taken place eight weeks later. There was no evidence to suggest dehydration on arrival, or of any dietary deficiency during their stay. The fall in haemoglobin concentration occurred in non-smokers and smokers alike. It is suggested that the initial haemoglobin was higher than normal, possibly due to a physiological response to stress, and that it returned to normal by the third day when the boys had become accustomed to their new environment.

Adolescent↗

The measurement of blood glucose and the definition of hypoglycemia.

Hypoglycemia is a chemical definition and must be distinguished from neuroglycopenia which is a clinical one. Accurate measurement of blood glucose is possible but many methods still in use may yield incorrect and sometimes dangerously misleading results. Various definitions of hypoglycemia are discussed in relation to methodology and technique of blood glucose measurement. The distinction between fasting and reactive hypoglycemia is emphasized.

Blood Glucose↗

Hypoglycemia--real and imaginary.

Hypoglycemia, and especially esential reactive hypoglycemia, is overdiagnosed in some parts of the world possible because of misplaced zeal on the part of certain clinicians or misinterpretation of laboratory data relating to the prolonged oral glucose test. This hypoglycemia quackerly has given rise to much concern amongst medical scientists, some of whom have felt it necessary to issue a public warning about the danger of misusing the diagnostic label of hypoglycemia.

Glucose Tolerance Test↗

[Prophylatic rhesus sensitization via intravenous administration of immunoglobulin G anti-D. III. Limits of the prophylaxsis obtainable by adapting the immunoglobulin dosage to the extent of the fetalmaternal blood transfusion (author's transl)].

Intravenously administered IgG anti-D permits a prophylatic rhesus sensitization. The size of the dose of immunoglobulin is adapted to the fetomaternal blood transfusion. The procedure is highly reliable in individual cases. The results acquired from a large control group, however, are not significantly better than the results obtained by other authors with intramuscular administration of IgG anti-D. Of the 1216 rh-negative mothers who were given follow-up checks, 1208 showed no active D-antibody formation as late as 7 months postpartum. An active D-antibody formation was found in 8 rh-negative mothers up to 14 days postpartum. These were anamnestic reactions. In 212 second pregnancies with a rh-postive child, 2 rh-negative mothers were sensitized in the rhesus system. The cause of this failure is thought to be the fact that the intravenously administered IgG anti-D did not gain access to the noncirculating D-positive erythrocytes in the pertioneal cavity of the mother.

Antibodies↗

A radioimmunoassay procedure for dexamethasone: plasma and urine levels in man.

A sensitive and precise dexamethasone radioimmunoassay method was applied to the determination of dexamethasone levels in the plasma and urine of human subjects who had received small doses of the drug by mouth. While the method can be applied directly to plasma, urine has to be diluted before assay. Very little cross-reaction was observed with two possible metabolites of dexamethasone. Both in the healthy subjects and in the group of patients investigated rapid absorption of dexamethasone from the gastrointestinal tract was observed. However, there appeared to be a large individual variation in the plasma concentration of the drug obtained after doses of the same size.

Adult↗

Gastrointestinal apudosis in obese hyperglycaemic mice.

Quantitative histological and immunocytochemical studies have been carried out on the endocrine cells of the gastrointestinal tract in genetically obese mice and their heterozygous (lean) litter mates. In the ob/ob mice hyperplasia of most of the endocrine (APUD) cells of the gut was found, a condition which can be described as apudosis. Quantitative histology of silver-stained preparations, using a method which demonstrates the majority of endocrine cells, showed a significant degree of hyperplasia in all regions of the gastrointestinal tract, with statistically significant differences in the upper intestine (p = less than 0.001). Quantitative immunocytochemical studies by image analysis showed a difference in both number and hormone content of Gastric Inhibitory Peptide (GIP) (p = less than 0.001) and Enteroglucagon (EG) cells in obese as compared to lean mice. Differences in the case of Secretin (S), Gastrin (G) and Vasoactive Intestinal Peptide (VIP) cells were not great but in the obese mice both S and G cells were present in larger numbers in the lower intestine whereas in the lean, and in normal mice, they are predominant in the upper intestine. Whether these complex gut endocrine changes are primary, or secondary to the metabolic abnormalities seen in the ob/ob mouse, cannot presently be determined.

Animals↗

Detection of cannabis products in urine by radioimmunoassay.

A radioimmunoassay specific for the closed, three-ringed cannabinoid nucleus was used to detect and measure caname from hospital inpatients not suspected of taking drugs. None of these contained tetrahydro-cannabinol cross-reacting cannabinoids (THC-CRC). The other 393 specimens were from patients known or suspected to be taking various drugs. Of these 51 out of 162 from one hospital treatment clinic and 19 out of 50 from another were positive for THC-CRC. Out of 107 urine specimens from an independent drug treatment clinic 71 were positive for THC-CRC, as were 13 out of 74 specimens from patients in whom drug misuse was suspected or thought possible.

Cannabis↗

Pituitary function in chronic alcoholism.

Elevated basal LH levels and an exaggerated response to LHRH were found in a high proportion of male chronic alcoholics. This was not associated with reduced plasma testosterone values. In addition, previous reports of an absent cortisol response to hypoglycaemia in a proportion of chronic alcoholics are confirmed.

Adult↗

Blood and urine gold levels during chrysotherapy for rheumatoid arthritis.

In this study the value of undertaking routine blood and urine estimations was assessed in relation to achieving maximum efficacy and safety in chrysotherapy. It was found that a favourable response to gold was forthcoming in approximately two-thirds of patients and occurred irrespective of the patients' disease duration or severity, or the mean serum gold level or the mean urinary gold excretion, estimated immediately before the next gold injection was due. The presence of rheumatoid nodules and the patients' advancing age were associated with a less favourable clinical response to gold. Those patients who derived a marked benefit from chrysotherapy did so significantly earlier in their course than those who derived only moderate benefit. A frequent correlation was seen in individual patients between serum gold levels and urinary gold excretion. This was most marked in those patients showing a favourable response to gold.

Adult↗

Prednisolone levels in the plasma and urine: a study of two preparations in man.

1. A competitive protein binding method was used to measure prednisolone and cortisol in blood and urine of volunteers given prednisolone by mouth (15 mg) in the standard tablet form and a fortnight later a regulated release formulation of prednisolone metasulphobenzoate containing an equivalent amount of prednisolone. 3. Plasma prednisolone levels rose rapidly after the standard tablet and more slowly after the regulated release form. The normal activity of the hypothalamic-pituitary-adrenal axis as measured by the 09.00 h plasma cortisol concentration was present 24 h after ingestion of the regulated release preparation. In contrast, the 09.00 h plasma cortisol level was reduced in subjects 24 h after receiving prednisolone in the standard tablet form.

Adult↗