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Biomedical subjects

M Stahl

Publications and source records attributed to M Stahl.

At least 163 records · Page 9Linked to original sources
PubMed1978

Interrelation of maternal and foetal glucose and free fatty acids. The role of insulin and glucagon.

At birth there is a statistically significant correlation between the maternal blood sugar and the umbilical venous and arterial blood glucose. The glucose concentration in the mother is higher than in the umbilical vein, and in the latter higher than in the umbilical artery. The free fatty acids also show a falling gradient from the mother to the umbilical vein and artery. This supports the assumption that glucose and FFA pass the placenta from the mother to the foetus. Insulin concentration is significantly higher in the mother than in the cord blood. There is however no difference between umbilical venous and arterial plasma insulin. A statistically significant correlation between glucose and insulin is only demonstrable in the maternal blood. Glucagon levels are about the same in maternal and umbilical arterial blood, but are significantly higher in umbilical venous blood. These results are consistent with the supposition that insulin and glucagon do not cross the placenta to a significant extent and can be synthesised by the foetus. In the first few hours after birth, a fall of glucose and a rise in FFA occur at the same time. Insulin tends to be lower than at birth and glucagon rises.

Blood Glucose↗
PubMed1978

Angioimmunoblastic lymphadenopathy: a T-cell deficiency.

The case of a 49-year-old man with the diagnosis of angioimmunoblastic lymphadenopathy is reported. The patient survived a stormy clinical course. The corticosteroids improved dramatically the clinical picture although the patient developed a staphylococcal septicemia. Before treatment immunological studies were done including quantitation of B and T-cells, antigen stimulation of lymphocytes in vitro, skin tests and skin window. Impairment of cell mediated immunity, decreased T-lymphocytes and increased B-lymphocytes were found. A decreased migration of lymphocytes in the skin window was also found compatible with immunosuppression. A possible presumptive pathogenetic mechanism is described although the cause of this recently described entity remains unknown.

B-Lymphocytes↗
PubMed1978

On the mechanism of p-piperidyl and p-benzyl sulfamyl benzoic acids transport by renal tissue.

The uptake of cyclic analogues of probenecid by kidney cortical slices has been studied in detail, in order to obtain more information on the secretory system for these compounds. Both p-piperidyl sulfamyl benzoic acid and p-benzyl sulfamyl benzoic acid were accumulated against concentration gradient, by renal tissue under aerobic as well as anerobic conditions. PAH, phenol red and probenecid competitively inhibited the active accumulation of these compounds by kidney tissue. Aerobic uptake of probenecid analogues was stimulated by succinate and octanoate at low medium concentrations while inhibition of renal accumulation of these compounds occurred at higher concentrations. Both p-piperidyl and p-benzyl sulfamyl benzoic acids like probenecid strongly interact with kidney cortex homogenates. Binding of these cyclic analogues to various cellular constituents of homogenate was efficiently inhibited by probenecid. The binding affinity of probenecid and analogues for kidney tissue, phospholipid vesicles (liposomes) and human serum albumin increased in the order : p-piperidyl sulfamyl benzoic acid less than p-benzyl sulfamyl benzoic acid less than di-n-propyl sulfamyl benzoic acid (probenecid). By contrast to the view put forward by Beyer (1950 & 1954), the results presented in this paper established that probenecid analogues are the true substrates of renal organic anion transport system.

Biological Transport↗
PubMed1977

Characteristics of accumulation of probenecid by rabbit kidney cortical slices.

Probenecid was accumulated by renal tissue both under aerobic and anaerobic conditions. The aerobic uptake at a low medium concentration of probenecid was enhanced three- or fourfold by acetate, while metabolic inhibitors and organic anions like p-aminohippurate (PAH), phenol red, and other substituted phenolsulphonphthalein (PSP) dyes which undergo secretion had an inhibitory effect. Octanoate and succinate stimulated aerobic probenecid uptake at low medium concentrations, but inhibited transport of the drug at high levels. Studies on renal homogenates showed that the anaerobic uptake of probenecid is due to binding to tissue constituents. Binding characteristics of PSP dyes to phospholipid vesicles and a representative binding protein, human serum albumin, exhibited close similarity to that of binding to renal tissue. Hydrophobic compounds like octanoate and PSP dyes partially inhibited probenecid binding. In contrast, transport of probenecid was almost completely abolished by these substances and PAH at high medium concentrations. On the basis of the results presented in this paper, it is concluded that renal transport of probenecid occurs by the common organic anion transport system.

Acetates↗
PubMed1977

[The complex radiological diagnosis of brain tumours (author's transl)].

By means of 50 cases of brain tumours the diagnostic rank of angiography, brain scintigraphy and pneumencephalography was determined. With combined inset of angiography and scintigraphy it was possible to reach a pretherapeutical correct diagnosis in 94% of the cases. The pneumencephalography was made additionally in 23 patients and useful additional informations about processes near by the ventricles were reached.

Adolescent↗
PubMed1976

[Metabolic differences between males and females and between normal and obese subjects during total fast].

In 24 normal and 24 obese subjects of both sexes circulating substrates (blood sugar, free fatty acids, ketone bodies) and hormones (insulin, growth hormone, pancreatic glucagon) were determined during 6 days of total fast. In normals the blood sugar fell to lower levels than in the obese. Plasma free fatty acids and ketone concentrations rose faster in normal than in obese subjects, and faster in females than in males. Plasma insulin concentrations declined to a greater extent in obese than in normal subjects. In all groups studied a significant increase of the pancreatic glucagon level within 1-3 days of fasting was observed, however, its rise occurred faster in normal females than in males. Growth hormone (GH) rose significantly in normal males but not in obese males. Following high overnight fasting values in some normal females showed no significant increase in GH levels but significantly higher GH values than obese females after 1-6 days of fasting. After summarizing starvation-induced metabolic changes common to all study groups the respective differences found between males and females and between normal and obese subjects are discussed.

Adult↗
PubMed1976

Inhibition of gastric acid secretion by blood drawing from an indwelling venous needle.

To investigate a possible inhibitory effect of blood drawing through an indwelling forearm vein needle on gastric acid secretion, 11 subjects were studied on four occasions each. The first session was for adapting the subject to the 3-hr collection of gastric juice. In 7 subjects the second through fourth sessions gave three conditions in balanced order: (1) an indwelling forearm vein needle and the withdrawal of 5 or 10 cc of blood every 20 min, (2) only a nonfunctional "dummy" needle implanted subcutaneously in the forearm skin, and (3) the control condition with no needle. In four additional subjects the sessions were identical except that condition (1) involved an indwelling forearm vein needle kept open by a slow infusion of saline solution and no blood was drawn. Phenol red recovery from an initial intragastric injection was measured in all. Results showed that blood drawing, but not saline infusion or venipuncture per se, inhibited gastric acid output.

Adult↗
PubMed1975

Nitrogen loss in normal and obese subjects during total fast.

Healthy volunteers of ideal weight (12 men and 12 women) were fasted for 6 days, and obese but otherwise healthy subjects (20 men, 28 women) for 6--28 days. In all groups studied a significant increase in urinary nitrogen loss from day 1 to day 3 of fasting was followed by a steady decrease. The early rise in urinary nitrogen excretion coincided with a rise in plasma glucagon levels, suggesting a relation of the latter to increased gluconeogenesis from amino acids. At equal weight greater nitrogen losses were found in men than in women, in both normal and obese subjects. In spite of much higher weight and larger energy expenditure and nitrogen loss in obese subjects however was not higher than in normal ones. Mean daily nitrogen losses varied from 14.5 g (normal and obese men early in starvation) to 3.0 g (obese women after a 4-weeks fast). Calculating the amount of calories derived from body protien (urinary nitrogen X 6.25 X 4.1)and taking total energy expenditure from tabular metabolic values, the contribution of protein to total calorie output was found to vary from 15% (normal men 6 day fast) to 5(obese women, 4th week of fasting). The clinical significance of nitrogen loss during therapeutic fasting is discussed.

Amino Acids↗
PubMed1975

[Clinical investigations of the effect of tolbutamide and glibenclamide on pancreatic glucagon secretion (author's transl)].

The effects of tolbutamide, glibenclamide, arginine and arginine in combination with glibenclamide upon insulin, glucagon and glucose serum levels have been studied in healthy young men. Sulphonylurea-induced hypoglycemia is followed by a reactive hyperglucagonemia. Arginine-induced hyperglucagonemia is not suppressed by sulphonylureas. While there exists no difference between tolbutamide and glibenclamide-stimulated glucagon secretion, there is one with regard to insulin secretion.

Adult↗