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Biomedical subjects

J F Caro

Publications and source records attributed to J F Caro.

138 records · Page 8Linked to original sources

A possible role for propranolol in the treatment of renal osteodystrophy.

The effect of propranolol upon parathyroid hormone (P.T.H) concentrations was investigated in patients undergoing chronic haemodialysis. 9 patients receiving propranolol for the treatment of hypertension or angina pectoris were compared with 25 similar patients not taking the drug. P.T.H. and alkaline phosphatase concentrations were lower in patients receiving propranolol and there was less radiological evidence of renal osteodystrophy in these patients. Prospective studies are needed to determine whether propranolol may be helpful as an adjunct to other therapy in reversing or preventing renal osteodystrophy.

Adolescent↗

Mechanisms of hypercalcemia in malignancy.

Various hormones have been implicated in the genesis of hypercalcemia in patients with malignancy. Ectopic secretion of PTH by tumor has been documented in only a few patients; rather, elevated levels of circulating iPTH have been presumed to reflect tumor production of hormone in most patients. Small fragments of PTH, as well as polypeptides larger than native PTH, have been described; their biological roles are unclear. The pattern of immunoreactivity, however, has been used to differentiate patients with ectopic hyperparathyroidism from patients with concomitant primary hyperparathyroidism. Vitamin D-like sterols produced by breast cancer seldom reach plasma levels necessary for physiological effects. Members of the prostaglandin family have been proposed to induce hypercalcemia through osteoclast activation or alteration of the immune system and also to affect the frequency of bone metastases. At present, no direct evidence is available to prove a direct role for these effects and prostaglandins are most useful as possible indicators of disease activity.

Bone Neoplasms↗

"Normal suppression" to dexamethasone in Cushing's disease: an expression of decreased metabolic clearance for dexamethasone.

The adrenal cortical function of a patient with pituitary-dependent Cushing's syndrome exhibited normal responsiveness to conventional doses of dexamethasone (Dex) over several years of evaluation. "Periodic hormonogenesis" did not seem to explain the phenomenon. Plasma concentrations of Dex were measured to ascertain whether an abnormality in Dex metabolism might explain the apparent discrepancy in Dex responsiveness. Plasma levels of Dex after oral administration of the steroid were higher than normal, suggesting that decreased clearance of Dex accounts for the phenomenon of "normal suppression" in this patient with Cushing's syndrome.

Adrenocorticotropic Hormone↗

Symptomatic hypocalcemia following combined calcitonin and mithramycin therapy for hypercalcemia due to malignancy.

Three patients with malignant disease received the usual recommended doses of mithramycin and calcitonin, either concurrently or concomitantly, because of severe life-threatening hypercalcemia. All three patients developed severe, symptomatic hypocalcemia. The mechanisms for this phenomenon are discussed. A possible synergism between calcitonin and mithramycin may prove to be hazardous in such patients and this possibility must be kept in mind when these agents are being considered as a combination treatment for hypercalcemia.

Calcitonin↗

Viability of fat obtained by syringe suction lipectomy: effects of local anesthesia with lidocaine.

The results of transplantation of free autologous fat obtained by blunt syringe suction lipectomy are unpredictable. We examined if adipose tissue viability is compromised by using syringe suction lipectomy and by infiltration of the tissue with local anesthetics. As reference, we used adipose tissue samples excised during elective surgery. Fat obtained intraoperatively and by lipectomy was digested with collagenase to isolate adipocytes. The mechanical damage associated with sample handling and cell isolation in both procedures was similar and did not exceed 6% of the total cell mass. In addition, cells isolated from intraoperative and lipectomy samples did not differ functionally, responded similarly to insulin stimulation of glucose transport and epinephrine-stimulated lipolysis, and retained the same growth pattern in culture. Since during fat transplantation the graft is exposed to local anesthetics at both the donor and the recipient sites, we reexamined adipocyte function in the presence of lidocaine. Lidocaine potently inhibited glucose transport and lipolysis in adipocytes and their growth in culture. That effect, however, persisted only as long as lidocaine was present; after washing, the cells were able to fully regain their function and growth regardless of whether the exposure was as short as 30 minutes or as long as 10 days. These results indicate that adipose tissue obtained by syringe lipectomy consists of fully viable and functional adipocytes, but local anesthetics may halt their metabolism and growth.

Adipocytes↗

Availability of insulin from total parenteral nutrition solutions.

Insulin is frequently required in total parenteral nutrition (TPN) solutions to control hyperglycemia. The purpose of this study was to evaluate the recovery of human insulin from standard TPN solutions with and without lipids and from TPN solutions with specialized amino acid formulations and to compare it to the insulin recovery from normal saline. All solutions were mixed in currently utilized PVC-free bags (ethylene vinyl acetate) and drained through PVC-containing tubing. Human insulin (Humulin-R) was spiked with 125I-labeled insulin and then added in concentrations of 10, 25, and 50 units to 1-liter bags containing 39-g amino acids (10% Freamine-III; or 6.9% Freamine HBC; or 8% Hepatamine), 257-g dextrose, electrolytes (Hyperlyte-R), 1000 units of heparin, MVI-12, and MTE-5 Concentrate. Alternate sets of bags contained 125 ml of 20% Intralipid and an appropriate amount of sterile water to keep the final volume at 1 liter. Actual clinical conditions of preparation, storage, and administration were simulated in this in vitro experiment. Multiple samples were collected during the 8-hr infusion period directly in gamma counter vials. All experiments and assays were done in triplicate. Our findings indicate that human insulin availability in TPN solutions is much higher (90%-95%) than the 50% suggested in the literature. Insulin recovery was not appreciably altered by adding lipids or by using Freamine HBC. Insulin recovery from TPN solutions was significantly reduced if they contained Hepatamine (87% and 88%, p less than 0.05) as compared to Freamine (90% and 94%).(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗

Galactorrhea in sarcoidosis: dynamic studies of prolactin, growth and gonadotropic hormone levels.

Five of 300 women with sarcoidosis had galactorrhea. Basal prolactin levels were mildly but significantly elevated when compared to controls and sarcoidosis patients without galactorrhea. Prolactin levels responded to thyrotropin releasing hormone and L-dopa administration, but not chlorpromazine. Luteinizing hormone and follicle-stimulating hormone concentrations responded normally to luteinizing hormone-releasing hormone in all sarcoidosis patients studied, as did growth hormone to insulin hypoglycemia. These results indicate that galactorrhea in sarcoidosis is an uncommon phenomenon, probably due to hypothalamic dysfunction and associated with mildly elevated prolactin levels.

Adult↗