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Biomedical subjects

A Korn

Publications and source records attributed to A Korn.

At least 109 records · Page 6Linked to original sources
PubMed1981

[Results of muscle biopsies in diphtheritic polyneuropathy. Light- and electron-microscopic examinations of muscle fibers, intramuscular nerves, motor endplates, and intramuscular vessels].

Muscle biopsies from the lower extremities of four patients with severe tetraplegic form of diphtheritic polyneuropathy were examined by modern techniques including histochemistry, electron microscopy and morphometric procedures. Until now comparable studies have not been published. The biopsies were removed during the acute stage of the polyneuropathy. We found scattered small angulated muscle fibers beside a more generalized slight atrophy predominantly of type 2 B fibers and targetoid-phenomenons or cores in type 1 fibers. Beside this neurogenic pattern there also were, corresponding with the results of electromyography, primary myogenic alterations with different degenerative phenomenons, suspicious of toxic origin as in cardiac muscle. The intramuscular vessels showed no abnormalities except some perivascular predominantly mononuclear cellular reactions with a remarkable number of cerebriform lymphoid cells, probably T-lymphocytes. No specific pathological alterations could be detected in 11 intramuscular nerves and two motor endplates. This may reflect the more proximal demyelination of human peripheral neurons by the diphtheria toxin as found in experimental diphtheria of the rabbit in contrast to the more distal type of the guinea pig.

Adolescent↗
PubMed1981

Effect of buformin on splanchnic carbohydrate and substrate metabolism in healthy man.

The effect of buformin (100 mg b.i.d. for 5 days) on carbohydrate metabolism, both splanchnic glucose output (SGO) and net substrate exchange were studied in 6 healthy male volunteers in the basal state and following glucose ingestion (100 g). Control studies without buformin were also performed in 5 men. Splanchnic glucose and substrate exchange was determined by means of the hepatic venous catheter technique. SGO was 154 +/- 18 (SEM) mg/min in the postabsorptive state and increased 33.3 +/- 2.8 g above the basal level during the 150 min period following glucose ingestion. Buformin administration did not alter basal SGO (157 +/- 26 mg/min), nor the splanchnic exchange of pyruvate, alanine, glycerol, OH-butyrate and acetoacetate. Splanchnic lactate balance was altered by buformin and net lactate output occurred. Following glucose ingestion the rise in splanchnic lactate output was increased, whereas no change in SGO (32.9 +/- 3.5 g/150 min) and splanchnic exchange of the other substrates was observed. The increase in arterial blood glucose concentration following oral glucose loading was reduced by buformin pretreatment (p less than 0.005). The insulin production rate (basal, 16 +/- 2 mU/min; following oral glucose, 13 +/- 2 U/150 min) as calculated from C-peptide release from the splanchnic area was unchanged by buformin. Except for a marked rise in splanchnic lactate production, buformin did not alter splanchnic carbohydrate metabolism after orally ingested glucose in healthy man. The diminished increase in arterial blood glucose concentration associated with unaltered insulin production suggests that buformin facilitates glucose utilization by peripheral tissues.

Adult↗
PubMed1980

[Urinary catecholamine excretion in women with a normal menstrual cycle (author's transl)].

The daily excretion of epinephrine and norepinephrine was analysed throughout one menstrual cycle in 8 normal women under every day circumstances. Blood levels of LH, FSH, prolactin, oestradiol, progesterone, testosterone and cortisol were determined by RIA every other day, or daily around the time of ovulation. No characteristic cyclic variations were found in epinephrine except for a peak in the premenstrual period, whilst norepinephrine was increased during menstruation and at about the time of ovulation in all women. The cortisol patterns showed no characteristic cyclic changes. Possible correlations are discussed between cyclic catecholamine changes and the well known psychological and emotional changes corresponding with the phases of the menstrual cycle.

Catecholamines↗
PubMed1980

[The effect of the calciumantagonist dimeditiapramine on thallium-201 myocardial perfusion during exercise in patients with coronary heart disease (author's transl)].

The effect of dimeditiapramine (Ro 11-1781), a new calciumantagonist, on thallium-201 myocardial perfusion during exercise was studied in a double-blind trial with 10 patients suffering from coronary heart disease. Treatment with a single intravenous dose of 1 mg/kg body weight resulted in a significant regional thallium-201 perfusion increase in 8 out of 10 patients. These results correspond with the clinically observed decrease in exercise-induced angina and ischaemic ECG alterations. The findings indicate that dimeditiapramine might be a useful anti-anginal drug.

Aged↗
PubMed1980

[Pharmacokinetics of trimethoprim and sulfametrol in patients with end stage renal failure and hemodialysis treatment (author's transl)].

In 6 patients with regular dialysis treatment the pharmacokinetics of intravenously administered trimethoprim and sulfametrol were investigated not only during dialysis procedure but also during the dialysis-free interval. Half-life of the free plasma sulfametrol component is normal even in cases with absent renal function and can be markedly reduced by hemodialysis treatment. The N4-acetylated main metabolite of the sulfonamide is - similar to trimethoprim - hardly dialyzable. Half-life of the latter drug component is prolonged in patients with far advanced renal failure. Due to the excellent dialysanceof the free plasma sulfonamide component the elimination of total sulfametrol is normal during hemodialysis despite cumulation of the N4-acetylated metabolite. Because of the tendency of this metabolite to cumulation, in dialysis patients the compound preparation of trimethoprim and sulfametrol should be used only for trasient treatment of acute infections.

Adult↗
PubMed1980

Prolactin in diabetic praecoma.

Prolactin has been suggested to exert a diabetogenic action in animal and man. Thus this report is concerned with the changes of serum prolactin in severely hyperglycaemic patients in a praecomatous state (n = 12). Basal serum prlactin levels were 12.0 +/- 3.4 (SE) ng/ml on admission and well within the normal range (less than 20 ng/ml). Rehydration of the patients which induced a significant fall in blood glucose (31.2 +/- 2.1 to 21.6 +/- 2.9 mmol/l) and in serum osmolality (336 +/- 9 to 316 +/- 10 mosmol/kg H2O) was however without any effect in serum prolactin concentration (9.9 +/- 2.5 ng/ml at the end of the rehydration period). We conclude that prolactin is not involved in the severe endocrine and metabolic derangements seen in diabetic praecoma; its secretion does not seem to be markedly altered by acute changes in blood glucose and serum osmolality.

Adolescent↗
PubMed1979

Insulin production rate following glucose ingestion estimated by splanchnic C-peptide output in normal man.

Insulin production rate has been estimated in healthy male volunteers (n = 16), and evaluated with respect to splanchnic glucose exchange. Insulin production rate was calculated from splanchnic immunoreactive C-peptide output. C-peptide secretion was estimated by the hepatic venous catheter technique both in the basal state and for 2 h following ingestion of various glucose loads (0, 12.5, 25, 50, 75, and 100 g). The results demonstrate a basal insulin production rate of 0.017 +/- 0.002 U/min (mean +/- SEM) or 2.04 U/2 h. Values rose in a dose dependent manner from 2.6 +/- 1.1 U/2 h after ingestion of 12.5 g of glucose to 10.8 +/- 1.1 U/2 h following a glucose load of 100 g. Insulin retention by the liver was estimated at 0.012 +/- 0.001 U/min in the basal state, and ranged from 47-85% (70 +/- 2%) of production following an oral glucose load. It was also demonstrated 1) that the relative splanchnic glucose output was inversely related to the amount of ingested glucose, and reached a minimum when glucose in excess of 50 g was ingested; and 2) that hepatic glucose retention was directly proportional to insulin production rate (r = 0.83; p less than 0.001; n = 15). It is suggested that the adaptive capacity of the splanchnic bed to retain glucose depending on the amount of ingested glucose guarantees that splanchnic glucose output fluctuates in healthy man only within a narrow range.

Adult↗
PubMed1978

Decrease of peripheral resistance after acute intravenous application of a new beta-receptor blocking agents, bufuralol HCl.

The hemodynamic effects of a new beta-receptor blocking agent, bufuraolo HCl, were compared with those of pindolol. Contrary to pindolol, bufuralol HCl induces a decrease of the peripheral resistance immediately. Under exercise conditions, the peripheral resistance increases under pindolol whereas it remains constant under bufuralol HCl in spite of reduced cardiac output. As an explanation, an effect of bufuralol HCl on peripheral resistance is discussed which might be independent of the beta-receptor blocking effects in the periphery.

Adrenergic beta-Antagonists↗
PubMed1977

Effect of exercise and of prolonged oral administration of propranolol on haemodynamic variables, plasma renin concentration, plasma aldosterone and c-AMP.

The effect of submaximal exercise upon haemodynamic and biochemical variables was investigated in healthy male subjects, aged 17-27 years, before and at the end of 2 weeks treatment with propranolol (40 mg p.o., q.i.d.). Propranolol reduced the resting blood pressure in normal subjects significantly. This effect was due to reduction of cardiac output and of systemic vascular resistance. No effect of propranolol on BP was seen during maximal exercise, since a reduced cardiac output was accompanied by an increased peripheral resistance. The reduction of cardiac output during exercise can be compensated in part by an increase in stroke volume. The sympathetic activity induced by physical exercise in normotensives increased plasma renin concentration (PRC) and plasma aldosterone (PA), and suppressed urinary excretion of c-AMP. PRC returned to basal levels after 45 min. No increase of PRC was observed after exercise in subjects treated with propranolol. Yet the increase of PA was not completely suppressed. No direct relation was demonstrated between PRC and the haemodynamic variables before or during the administration of propranolol.

Administration, Oral↗
PubMed1977

Pharmacokinetics of Lidaprim in cases of impaired renal function.

Elimination half-life times, plasma concentrations, and minimal cumulation factors are being determined resp. calculated for trimethoprime and sulfametrole (free as well as total amounts)--both combination partners of Lidaprim--in healthy volunteers and in patients with impaired renal function. There is a strong influence of renal function on the cumulation of the metabolized part of the sulfonamide, a weaker one on trimethoprime, and almost none on the free sulfonamide. On account of the sulfonamide metabolite cumulation, a reduction by half of the standard dose of Lidaprim is recommended if the creatinine clearance is below 20-30 ml/min.

Adult↗
PubMed1975

Urinary catecholamine excretion and thyroid hormone blood level in the course of severe acute brain damage.

Urinary catecholamine excretion and thyroid hormone blood level were studied in 16 patients following severe cerebral trauma. Increased excretion rates of epinephrine and norepinephrine were found. There was no significant difference in the catecholamine excretion when compared with generally traumatized patients. The relationships between catecholamine excretion, increased metabolic rates, and negative nitrogen balance indicate that in patients with a midbrain syndrome there exists an additional diencephalic metabolic factor, which leads to a rise in fat oxidation and perpetuation of catabolism. Early high caloric parenteral nutrition seems to inhibit the initial increase of catecholamine excretion and thus protects the body from an unnecessary breakdown of its own reserves. If the course is classified according to neurological stages, it can be shown that patients with a traumatic apallic syndrome in poor condition have a high increase of catecholamine excretion. Secretion of thyroid hormones is not influenced significantly by cerebral trauma.

Adolescent↗
PubMed1975

[On the multiple-dose kinetics of glibornuride in man (author's transl)].

The multiple-dose pharmacokinetics of 1-(2-endo-hydroxy-3-endo-bornyl)-3-(p-tolyl-sulfonyl)-urea (glibornuride, Glutril¿) was examined in 7 subjects with maturity-onset diabetes treated with the drug over a period of 4 weeks (25 mg every twelve hours). The steady-state levels of glibornuride (maximum and minimum concentrations) were determined experimentally and by calculation (using the pharmacokinetic parameters obtained following oral administration of 50 mg glibornuride on the 1st day of the treatment). There was good agreement between experimental and calculated values. The results afford evidence for the regular pharmacokinetic pattern of glibornuride. There was neither unexpected accumulation of the drug nor diminution of the steady-state levels as might occur as a consequence of induction of microsomal enzymes.

Biological Availability↗