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Biomedical subjects

A Pont

Publications and source records attributed to A Pont.

12 recordsLinked to original sources

Unusual causes of hypercalcemia.

The unusual causes of hypercalcemia have been reviewed. These disorders are rarely derived as the cause of hypercalcemia from the usual tests that one obtains in working up hypercalcemic patients (such as PTH level, phosphorus, urinary calcium). These diagnoses (particularly drug-related hypercalcemia) can be determined only from a careful history. The vast majority of hypercalcemic patients have disease secondary to cancer, hyperparathyroidism, or disorders of vitamin D metabolism. It should be noted that some hypercalcemic patients may have more than one disease. Therefore, before assuming that a hypercalcemic patient with Paget's disease, thiazide ingestion, immobilization, or so forth has hypercalcemia secondary to the primary disorder, hyperparathyroidism and cancer should also be considered. Similarly, serum calcium levels can normalize in some patients with mild hyperparathyroidism or bony metastases with mobilization and/or cessation of thiazide therapy.

Diagnosis, Differential

Long-term experience with high dose ketoconazole therapy in patients with stage D2 prostatic carcinoma.

The antifungal drug ketoconazole has been shown to block testosterone synthesis. High dose ketoconazole therapy was given to 17 patients with previously untreated stage D2 prostatic cancer. Rapid relief of pain occurred in 15 patients with significant pain. Prostatic acid phosphatase levels normalized or decreased in all patients. Bone scan scores were stable or improved. Two patients remain on therapy for more than 30 months. The remainder have ceased treatment owing to subsequent progressive disease (5 patients), side effects (6) or noncompliance. Eleven patients who had relapse after previous endocrine ablative therapy were treated with ketoconazole. Subjective responses were frequent but long-term objective responses were rare. There was a high incidence of side effects, particularly nausea. Ketoconazole may have limited usefulness as initial therapy in patients with endocrine responsive advanced prostatic cancer. The drug can be palliative in some patients who have failed previous therapeutic modalities. Analogues of the drug should prove to have better efficacy and fewer side effects.

Aged

Inhibition of cholesterol synthesis by ketoconazole.

To determine if ketoconazole influences cholesterol metabolism in humans, plasma lipid levels were studied in seven men with advanced prostate cancer who were being treated with high-dose ketoconazole. Additionally, the effects of ketoconazole on cholesterol synthesis in cultured normal human fibroblasts were studied. High-dose ketoconazole therapy caused a 27 percent reduction in total serum cholesterol values without affecting serum triglyceride levels. The reduction in serum cholesterol levels was maintained for five months in six of seven patients. The fall in total cholesterol levels was due to a 38 percent reduction in low-density lipoprotein cholesterol levels without associated changes in high-density lipoprotein cholesterol levels. Serum lanosterol levels increased 46 percent during ketoconazole treatment. Studies in cultured normal human fibroblasts showed that ketoconazole inhibited cholesterol synthesis by blocking the conversion of lanosterol to cholesterol. These results establish that ketoconazole is a potent inhibitor of cholesterol production in vivo and in vitro.

Aged

Recurrence after a surgically induced remission.

In December 1976, an 18-year-old woman had symptoms typical of Cushing's syndrome. Laboratory evaluations and roentgenograms documented pituitary-dependent Cushing's disease in a patient with a pituitary microadenoma. In May 1977, she underwent transsphenoidal pituitary exploration. A 2-mm pituitary microadenoma was removed. The patient improved, and laboratory evaluation documented remission of the disease. In June 1978, she again complained of symptoms compatible with Cushing's disease. Laboratory evaluation confirmed a pituitary-dependent hypercortisonism. This case report marks the first recurrence of Cushing's disease in a patient previously cured by transsphenoidal resection of a pituitary tumor.

Adenoma

Prolactin-secreting tumors in men: surgical cure.

Two men presented with decreasing libido and impotence. Endocrine evaluation showed that they both had low levels of serum testosterone and a prolactin-secreting adenoma. Transsphenoidal removal of their tumors resulted in normalization of serum prolactin and testosterone concentrations and normalization of sexual function. These patients represent the first two nonacromegalic men with prolactin-secreting tumors and hypogonadism in whom surgical resection of their tumors resulted in a complete clinical and biochemical remission. We discuss the effects of elevated prolactin on male sexual function.

Adenoma

Diabetes mellitus and neuropathy following Vacor ingestion in man.

Two patients ingested Vacor, a rodenticide containing the active ingredient N-3 pyridylmethyl-N'-p-nitrophenyl urea. Both patients developed ketosis-prone diabetes mellitus and severe autonomic neuropathy. Niacinamide therapy given nine hours after Vacor ingestion in one patient and 14 hours after ingestion in the other was not successful in preventing these sequelae. Physicians need to be aware of the toxicity of Vacor, and the potential therapeutic benefit of early niacinamide therapy.

Adult

Familial hemochromatosis. Physiologic studies in the precirrhotic stage of the disease.

We studied 12 members of a family with precirrhotic hemochromatosis to define the physiologic abnormalities in the asymptomatic phase of the disease. Six of 12 had increased iron stores; the mode of inheritance was consistent with an autosomal dominant trait. Serum ferritin levels were no more predictive of tissue iron levels than measurements of serum iron, transferrin saturation or chelatable iron excretion. In three affected family members intestinal iron content was normal. Liver proline hydroxylase activity and urinary hydroxyproline excretion did not correlate with tissue iron content, suggesting that, in addition to the possible role of tissue iron, hepatic fibrosis may involve other factors. "Borderline diabetes mellitus" was present in three affected family members, but extensive studies revealed that pituitary dysfunction is uncommon in early hemochromatosis. Increased levels of liver iron proved to be the most reliable marker for the disease.

Adolescent