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Biomedical subjects

L Axelrod

Publications and source records attributed to L Axelrod.

At least 55 records · Page 3Linked to original sources

Prostacyclin production by isolated adipocytes.

Isolated rat adipocytes produce prostacyclin (PGI2) in relatively large quantities during norepinephrine (NE)-induced lipolysis. The endogenous NE-induced production rate of PGI2, calculated from the NE-induced production rate of PGI2 observed in our studies (2.2 ng/10(6) cells/2 h) and from the number of fat cells in the normal organism, is 1.46 ng/kg/min for rats, 4.46 ng/kg/min for men, and 11.86 ng/kg/min for women. These rates are comparable to the exogenous PGI2 infusion rate that alters platelet aggregation and blood pressure in rats and humans. Exogenous PGI2 failed to modify the rate of NE-induced lipolysis. Inhibition of endogenous PGI2 production by indomethacin had no effect on the rate of NE-induced lipolysis when either a maximal or submaximal lipolytic concentration of NE was used. PGI2 [rather than prostaglandin (PG) E2] may be the substance that accounts for the functional vasodilatation that accompanies hormone-induced lipolysis. PGI2 is produced in large quantities than PGE2 during NE-induced lipolysis and is a more potent vasodilator than PGE2. Its instability can account for the inability of previous investigators to detect a vasodilator substance in the venous effluent of adipose tissue. The production of PGI2 by adipocytes may be an important modulator of the regulation of vascular tone and platelet aggregation by catecholamines in the vascular bed of adipose tissue and perhaps other tissues. PGI2 produced by adipocytes, by virtue of its ability to cause vasodilatation and inhibit platelet aggregation, may contribute to the maintenance of luminal patency in the vascular bed of adipose tissue and possibly other tissue as well.

6-Ketoprostaglandin F1 alpha↗

U-500 insulin in the treatment of antibody-mediated insulin resistance.

Three patients with antibody-mediated insulin resistance were treated with U-500 regular insulin subcutaneously. Insulin requirements decreased dramatically (55% to 75%) when therapy was changed from U-100 NPH pork to equivalent doses of U-500 regular pork insulin. There was no difference in antibody affinity for the insulin in these two preparations as shown by competition experiments. These observations demonstrate that U-500 insulin is a useful alternative in the treatment of antibody-mediated insulin resistance. The mechanism for this effect is yet to be determined.

Adult↗

The treatment of the hepatorenal syndrome with intra-renal administration of prostaglandin E1.

Three patients with the hepatorenal syndrome were treated with prostaglandin E1 administered through a selective renal arterial catheter. Prostaglandin E1 was given in progressively increasing doses (2 to 100 ng/kg/min) over a 60-minute period. Control plasma prostaglandin E levels were elevated in all three patients, 0.98, 0.91, and 0.83 ng/ml, respectively. At the end of the infusion, plasma prostaglandin E levels had risen to 10.4, 2.63, and 10.3 ng/ml in the three patients respectively. Plasma renin activity increased during the course of the infusion in two of the patients. The plasma aldosterone concentration did not change during the prostaglandin E1 infusion. Intrarenal prostaglandin E1 failed to increase urine volume or urinary sodium concentration in three patients with the hepatorenal syndrome.

Adult↗

Glucocorticoid therapy.

1. There is a poor relationship between the circulating half-life a glucocorticoid and either its potency or its duration of action. Many actions of a glucocorticoid have unequal durations. The duration of action varies with the dose. 2. The presence of biological activity as a glucocorticoid depends on the presence of a hydroxyl group at carbon number 11. Cortisone and prednisone, which are 11-keto compounds, must be converted to 11-beta-hydroxyl compounds to be effective. This reaction may be impaired in the presence of liver disease. 3. Iatrogenic Cushing's syndrome differs from spontaneous Cushing's syndrome in several respects, possibly because in the former ACTH is suppressed but in Cushing's syndrome associated with bilateral adrenal hyperplasia ACTH levels are elevated...

Adrenal Glands↗

Medical education and practic in People's Republic of China.

A dramatic adaptation of medical education to meet indigenous needs and circumstances has occurred in the People's Republic of China in the context of a highly structured health care delivery and medical referral system, entailing a reduction in curriculum length from 6 to 3 years. Although general directions and guidelines are set centrally by Peking, considerable autonomy and flexibility exist in individual schools. The innovative approaches used include training medical students in countryside and factories as well as medical schools, combining traditional Chinese and modern Western medicine, opening hospital-run medical schools, and using unconventional methods of producing medical doctors. On graduation the students generally return to the communities from which they came. Although the total number of medical graduates still falls short of national requirements, the problem of maldistribution of physicians has been alleviated in China. Medical care is now readily available in rural areas, where 80% of the population resides.

China↗

Studies of the control of plasma aldosterone concentration in normal man. II. Effect of dietary potassium and acute potassium infusion.

The responses of plasma aldosterone, cortisol, and corticosterone to an infusion of 75 mEq of potassium chloride over 120 min were studied in 10 normal subjects. Five subjects were fed a 10 mEq and five a 200 mEq sodium diet, while all subjects ingested 40 mEq and 200 mEq potassium sequentially. Two potassium infusions were performed in each subject when in balance on a fixed sodium intake and low and then high potassium diets. Regardless of dietary intake, increases of serum potassium of 0.5-1.5 mEq/liter above preinfusion levels were usually associated with significant increments in plasma aldosterone concentration. Our data agree with previous evidence that the potassium ion stimulates the adrenal cortex directly to secrete aldosterone. Peripheral renin activity did not increase after the potassium infusion. Plasma cortisol and corticosterone levels generally followed the expected diurnal decline during the infusion, implying that ACTH secretion did not increase. The plasma aldosterone response to incremental changes in serum potassium was linear on each of the four diets. The slopes of these linear relationships increased significantly when the potassium intake was increased from 40 to 200 mEq. No increase in slope occurred on either potassium intake when dietary sodium was restricted from 200 to 10 mEq. Thus, identical increases in serum potassium were associated with greater increments in plasma aldosterone above preinfusion levels on either sodium intake when the 200 mEq potassium diet was compared with the 40 mEq potassium intake.

Adrenal Glands↗

Nesidioblastosis associated with insulin-mediated hypoglycemia in an adult.

Nesidioblastosis, the process of differentiation of pancreatic islets from ductular epithelium, is a well-described cause of insulin-mediated hypoglycemia in neonates and infants, but not in adults. A 58-yr-old woman with characteristic clinical features of fasting hypoglycemia had inappropriately elevated plasma immunoreactive insulin levels during symptomatic episodes of fasting hypoglycemia. Angiography, palpation at laparotomy, and resection of the distal three-quarters of the pancreas provided no evidence of a tumor. Pathologic examination of the resected pancreas revealed the findings of nesidioblastosis, i.e., budding of islets from the wall of ductules, and also increased number and size of islets and abnormal shape and location of islets. An entire spectrum of islet cell abnormalities including nesidioblastosis can cause insulin-mediated hypoglycemia in adults, as it does in neonates and infants.

Adenoma, Islet Cell↗