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Biomedical subjects

M Berger

Publications and source records attributed to M Berger.

At least 955 records · Page 53Linked to original sources
PubMed1979

Effect of physical training on glucose tolerance and on glucose metabolism of skeletal muscle in anaesthetized normal rats.

The effect of physical training on glucose tolerance in vivo and skeletal muscle glucose metabolism in vitro was investigated in normal rats. Treadmill running for 10 days up to 240 min/day led to a decrease of basal and glucose-stimulated plasma insulin levels without major alterations of the IV glucose tolerance (1 g/kg body weight). Swim training of two weeks' duration, i.e. exercise up to 2 X 75 min/day, which did not induce significant changes in body composition, skeletal muscle glycogen levels or citrate synthase activity, resulted in a significant improvement of IV glucose tolerance and substantial reductions of basal and glucose-stimulated plasma insulin levels. Associated with this apparent improvement of insulin sensitivity in vivo, significant increases of the insulin-stimulated glucose uptake (+ 55%) and lactate oxidation + 78%) in vitro were found on perfusion of the isolated hindquarter of swim-trained animals. It is suggested that mild physical training can improve glucose tolerance and insulin sensitivity in normal rats, at least in part, due to an increase of insulin sensitivity of skeletal muscle glucose metabolism.

Anesthesia↗
PubMed1979

Absorption kinetics of subcutaneously injected insulin. Evidence for degradation at the injection site.

The absorption of subcutaneously injected insulin was examined by injecting semisynthetic [3H] insulin in anaesthetized pigs and subsequently analysing the tissue excised from the injection site. Contrary to previously accepted views, a significant proportion of insulin was degraded at the injection site. The disappearance of intact [3H] insulin from the injection site followed a monoexponential function with a half-time of 59 min.

Absorption↗
PubMed1979

Percentage binding of testosterone and dihydrotestosterone and unbound testosterone and dihydrotestosterone in rabbit maternal and fetal plasma during sexual organogenesis.

The percentages of bound testosterone (17 beta-hydroxy-4-androsten-3-one; T) and dihydrotestosterone (17 beta-hydroxy-5 alpha-androstan-3-one; DHT) and their unbound concentrations were determined in pregnant rabbits and their fetuses from the 18th day of gestation to birth. T and DHT were also measured in fetal testes. In the testis, the total T/total DHT ratio, very high at 22 days (73.7 +/- 15.2), decreased until birth (6.7 +/- 0.8). In male fetuses the concentrations of total and unbound circulating T and DHT were always low and did not show any peak during sexual organogenesis. The percent binding of T (from 73.0 +/- 0.5 to 77.6 +/- 0.6) and DHT (from 76.5 to 83.7 +/- 1.1) in fetuses were similar in both sexes and significantly lower than those measured in mothers (T: from 87.2 +/- 0.6 to 91.6 +/- 0.9; DHT: from 87.3 +/- 0.9 to 93.8 +/- 0.9).

Animals↗
PubMed1979

Urinary kallikrein excretion in idiopathic nephrotic syndrome.

The plasma kallikrein-kinin system, a potent vasodilator, has been implicated in causing the protein loss of the idiopathic nephrotic syndrome. However, the kidney possesses a kallikrein-kinin system separate from the plasma system. Thus, urinary kallikrein may reflect more accurately intrarenal events. Using a radiochemical esterolytic assay we measured the urinary kallikrein excretion in a patient with a minimal lesion nephrotic syndrome during relapse. Protein excretion was initially elevated (8.1 plus or minus 2.0 gm. per 24 hours) as was urinary kallikrein excretion (96.4 plus or minus 46.6 EU per 24 hours). After initiation of steroid therapy protein and kallikrein excretion decreased significantly (p less than 0.05). During the entire study kallikrein excretion was significantly correlated with protein excretion (r equals 0.89, p less than 0.01). It is tempting to speculate that activation of the intrarenal kallikrein-kinin system participates in the protein loss characteristic of the nephrotic syndrome.

Amylases↗
PubMed1979

Unsuspected hypertrophic subaortic stenosis in the elderly diagnosed by echocardiography.

Idiopathic hypertrophic subaortic stenosis (IHSS) occurs more commonly in the elderly than is generally believed, and is often unsuspected. In 26 patients above the age of 60, the diagnosis was recognized in only 7 (27 percent) prior to echocardiography. Symptoms included dyspnea in 17, chest pain in 16, and dizziness or syncope in 8 patients. In 10 patients, establishing the correct diagnosis led to therapy with propranolol, with or without discontinuation of digitalis; in 7 of these, the chest pain was significantly reduced. An accurate diagnosis is particularly important because drugs that are useful in other forms of heart disease may have adverse effects in IHSS. Echocardiography is the diagnostic procedure of choice and is indicated in the presence of an unexplained systolic murmur, especially when it is associated with chest pain, syncope or left ventricular hypertrophy.

Aged↗
PubMed1979

Plasma glucagon in diabetes of haemochromatosis: too low or too high?

Glucagon secretion before and during arginine infusions was tested in 11 patients with diabetes associated with haemochromatosis. The results were compared with those obtained in six normal subjects and five patients with haemochromatosis but normal glucose tolerance. The patients with haemochromatosis, regardless of glucose tolerance, exhibited higer level of plasma immunoreactivity for glucagon (antiserum 30-K) suggesting hyperglucagonaemia. However, additional analysis revealed that a considerable amount of this glucagon immunoreactivity was due to cross-reacting material of high molecular weight, the levels of which were significantly higher in patients with idiopathic haemochromatosis. When this was deducted from the total immunoreactivity measured, the resulting values for true glucagon concentrations were similar to those of normal subjects. The data suggest that (1) patients with idiopathic haemochromatosis, whether or not associated with diabetes, exhibit plasma glucagon levels comparable with those of normal subjects; (2) the plasma of the same patients contains significantly more high-molecular-weight substances reacting with glucagon antiserum 30-K than is present in plasma of normal subjects; and (3) 'hyperglucagonaemia' may be erroneously suggested when glucagon is measured with certain antisera reputed to be specific for glucagon.

Arginine↗
PubMed1979

Effect of luteinizing hormone-releasing hormone on plasma testosterone in immature and adult male rabbits.

1 microgram/100 g body weight of synthetic luteinizing hormone-releasing hormone (LHRH) was administered to immature (25, 35 and 55 days of age) and adult (180 days) male rabbits. Testosterone was measured by radioimmunoassay in plasma samples taken just before and 30 min after LHRH injection. At all stages studied, LHRH significantly increased plasma testosterone. Expressed as a percent of over basal levels, the plasma testosterone was increased by 2,695% at 25 days, 3,955% at 35 days, 6,032% at 55 days and 3,766% at 180 days. Expressed in absolute amounts, the plasma testosterone levels showed an increase of 520 pg/ml at 25 days, 604 pg/ml at 35 days, 1,189 pg/ml at 55 days and 7,596 pg/ml at 180 days. The exact interpretation of the data was difficult since it is dependent on the mode of expression used. Nevertheless, the results support the observation that the hypophyso-testicular axis is functional in immature rabbits.

Age Factors↗
PubMed1979

The role of physical exercise and training in the management of diabetes mellitus.

The effects of physical activity on blood glucose homeostasis in diabetes mellitus and the potential benefits of exercise in the treatment of diabetic patients, are reviewed. Mild physical exercise results in a fall of blood glucose levels in controlled diabetic patients; this acute effect of exercise might be used in particular to inhibit the rise of blood glucose seen in insulin-treated diabetics after food intake. In contrast, physical activity will further deteriorate the metabolic situation in decompensated diabetic patients by an increase in blood glucose and a rapid aggravation of ketosis. On the other hand exercise potentiates the blood glucose lowering effect of subcutaneously injected insulin; therefore precautions have to be taken in order to avoid hypoglycemia in insulin-dependent diabetics especially during and after more strenous exercise. In juvenile-type diabetes, physical activity can be used as an efficient therapeutic adjunct only in cooperative, well-instructed patients who are used to check their metabolic situation on a regular basis. Physical training increases the tissues' sensitivity towards (endogenous) insulin. Hence, in addition to the diet, training might represent the most appropriate treatment in maturity onset-type diabetic patients. However, direct evidence for an improvement of glucose tolerance in diabetic patients by physical training is still lacking. In order to formulate detailed, generally applicable recommendations on how to carry out a useful therapeutic program of physical exercise and/or training in diabetic patients, further clinical studies assessing the quantitative effects of physical activity on carbohydrate metabolism are needed.

Animals↗
PubMed1979

Glucagon immunoreactivities and amino acid profile in plasma of duodenopancreatectomized patients.

Glucogon immunoreactivity (IRG) was measured in plasma of duodenopancreatectomized subjects with a nonspecific (K-4023) and a specific (30-K) glucagon antiserum. After an overnight fast, plasma IRG (K-4023) was significantly (P < 0.05) higher in the subjects without pancreas, averaging 782+/-79 (SEM) pgeq/ml, than in the controls (482+/-80 pgeq/ml). IRG (30-K) of 162+/-68 pg/ml did not change during an infusion of arginine (450 mg/kg per 40 min). Insulin deprivation during 3 d in one patient did not restore the IRG response to arginine as reported in depancreatized dogs.Bio-Gel P-30 column chromatography revealed that virtually all IRG (30-K) measured in whole plasma was of different molecular weight than glucagon, and primarily of a mol wt >/= 40,000. Intravenous arginine did not significantly alter the chromatographic pattern of these plasmas. Thus, as postulated by others, duodeno-pancreatectomized humans have virtually no circulating 3,500-dalton glucagon. Hence, the presence of 3,500-dalton glucagon in plasma is not a condition for the diabetic state. It might, nevertheless, when present in normal or excessive amounts, worsen the metabolic state of diabetic patients. Among 14 amino acids measured in plasma of these patients, the concentrations of alanine, serine, ornithine, and arginine were significantly (P < 0.05) elevated to approximately twice that of normal: alanine and serine are both substrates for gluconeogenesis, whereas ornithine and arginine are involved in the formation of urea, the second product of hepatic gluconeogenesis. As the concentrations of branched chain amino acids were not grossly altered, it is hypothesized that this amino acid pattern is a consequence of glucagon deficiency rather than secondary to the diabetic state of these patients.

Adult↗
PubMed1979

Changes in the testosterone to dihydrotestosterone ratio in plasma and testes of maturing rabbits.

Testosterone (T) and dihydrostestosterone (DHT) were radioimmunologically assayed in the testes and plasma of rabbits at 1, 10, 20, 40, and 60 days of age and at 3, 4, 5, and 8 months. In the testis (nanograms per 100 mg testis) and plasma (picograms per ml), both hormones are low at birth, reach their maxima between 60--90 days, and then decline and remain low after 120 days. In the testes, the T:DHT ratio is very high from birth (4.2 +/- 0.4) to 60 days (8.8 +/- 1.1). A significant decrease (P less than 0.001) occurs between 60 (8.8 +/- 1.1) and 90 (1.2 +/- 0.1) days. The T:DHT ratio is always less than or equal to unity after 90 days. From 1--60 days, T is the dominant testicular hormone, while the levels of DHT are greater than or equal to those of T after 60 days. The mean value of the plasma T:DHT ratio is always greater than unity from birth (1.7 +/- 0.4) to adulthood (2.6 +/- 0.7). The dominant circulating hormone, at all ages, is T. Our results show that sexual maturation in rabbits is characterized by an inversion of the T:DHT ratio in the testes but not in the plasma.

Aging↗
PubMed1979

Developmental patterns of the testicular response to experimental modifications of circulating androgen levels in the fetal rabbit.

The circulating level of free androgens in fetal and newborn rabbits was reduced by active immunization of mothers against testosterone (T) or was increased by injecting dihydrotestosterone (DHT) into the mothers. After immunization, about 100% of the circulating T and DHT in fetuses was bound. After maternal injection of DHT, the circulating level of this hormone in fetuses was increased 2- to 120-fold. The effects of these treatments were evaluated by determining testicular levels of T, a physiological index of circulating gonadotropin. From 20--23 days of gestation, testicular T content was modified neither by circulating antibodies nor by an increase of blood DHT. The same overloads of circulating DHT, which were ineffective between 20--23 days, significantly reduced testicular T content between 25--29 days. Testicular T content was significantly increased in newborns from immunized mothers. These results suggest that the appearance of the negative feedback action of circulating androgens takes place relatively late, at 24 or 25 days, after differentiation of the genital tract.

Animals↗