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Biomedical subjects

M Schaaf

Publications and source records attributed to M Schaaf.

35 records · Page 2Linked to original sources
PubMed1980

Skeletal responsiveness in pseudohypoparathyroidism. A spectrum of clinical disease.

Three cases of pseudohypoparathyroidism with roentgenographic evidence of hyperparathyroid bone disease are described. Renal resistance to exogenous parathyroid hormone (PTH), the hallmark of pseudohypoparathyroidism, was documented by markedly blunted or absent urinary phosphate and cyclic AMP responses to parathyroid extract. At the time of diagnosis all patients were hypocalcemic and hyperphosphatemic with elevated serum alkaline phosphatase levels and subperiosteal resorption noted on skeletal films. Bone biopsy in one patient revealed a histologic appearance consistent with hyperparathyroidism. Serum PTH levels, measured in two patients while they were hypocalcemic, were elevated. None of the patients had short stature, brachydactyly, subcutaneous calcification or mental deficiency. These cases are compared to the 15 well-documented cases previously reported. The presently available information on pseudohypoparathyroidism indicates a variable skeletal response to PTH mediated by several factors extrinsic to bone and suggests that pseudohypoparathyroidism with hyperparathyroid bone disease is one extreme of a clinical spectrum of skeletal responsiveness to PTH. This disorder is part of an expanding clinical picture which makes pseudohypoparathyroidism a diagnostic consideration in any patient with unexplained hypocalcemia, hyperphosphatemia, elevated alkaline phosphatase levels or metabolic bone disease.

Adolescent↗
PubMed1979

Acromegaly and the heart. An echocardiographic study.

Twenty-seven patients with acromegaly had echocardiograms performed to delineate the ventricular septum, left ventricular posterior wall and mitral valve. Left ventricular function was assessed by calculating the systolic internal dimensional shortening of the left ventricle. Six patients met the criteria for asymmetric septal hypertrophy and eight had concentric left ventricular hypertrophy. The remaining 13 patients were categorized as "normal," although six had septal measurements greater than 11 mm. The group with asymmetric septal hypertrophy had significantly greater percentage of internal dimensional shortening during systole than either the normal group (p less than 0.05) or the group with left ventricular hypertrophy (p less than 0.01). Initial mean growth hormone levels were considerably higher in the group with left ventricular hypertrophy than in the normal group (93 versus 34 ng/ml). Thus, echocardiographic abnormalities are common in acromegaly, and patients with asymmetric septal hypertrophy and acromegaly appear to have significantly increased ventricular ejection. Many of the patients with left ventricular hypertrophy have no evidence of clinical cardiovascular disease, and their left ventricular hypertrophy may be related to higher initial growth hormone levels.

Acromegaly↗
PubMed1979

Absent growth hormone response to L-tryptophan in acromegaly.

In acromegaly, regulation of GH secretion by dopamine pathways appears to be qualitatively abnormal. To determine whether regulation of GH secretion by serotonin pathways is also abnormal in acromegaly, we administered L-tryptophan (5 g orally), the initial precursor of serotonin, to 10 patients with active acromegaly (9 treated and 1 untreated), 3 patients with cured acromegaly, and 8 normal subjects. The normal group showed a significant (P less than 0.05) increase in serum GH after L-tryptophan [peak value, 12.3 +/- 4.0 (se) ng/ml], though the magnitude of the response was highly variable. In contrast, subjects with active acromegaly did not show an increase in serum GH after L-tryptophan [mean integrated percentage change in serum GH, -25 +/- 25% (SE); P = NS]. One patient whose acromegaly had been surgically cured did show a GH rise after L-tryptophan. In acromegaly, the GH response to L-tryptophan is absent, suggesting that regulation of GH secretion by serotonin pathways might be qualitatively abnormal.

Acromegaly↗
PubMed1978

Parameters of thyroid function in patients with active acromegaly.

In order to determine if acromegaly per se may be associated with abnormalities in thyroidal economy, serum thyroxine-binding globulin (TBG), resin T3 uptake, total and free T4, T3, and reverse T3 concentrations were measured in 21 patients with active acromegaly. Mean (+/- SE) total T4, T3, and reverse T3 levels were 7.1 +/- 0.2 microgram/dl, 111 +/- 4 ng/dl, and 45 +/- 2 ng/dl, respectively, and the mean TBG concentration was 3.6 +/- 0.2 mg/dl. Similarly, mean free T4, T3, and reverse T3 concentrations were 2.4 +/- 0.09 ng/dl, 383 +/- 22 pg/dl, and 118 +/- 7 pg/dl, respectively. None of these values is significantly different from normal and the thyrotropin response to thyrotropin-releasing hormone was also normal. In contrast to several earlier reports, these data suggest that parameters of thyroid function are generally normal in patients with active acromegaly.

Acromegaly↗
PubMed1978

The syndrome of basal encephalocele and hypothalamic-pituitary dysfunction.

We documented hypothalamic-pituitary dysfunction in three patients with congenital herniation of the brain through the base of the skull (basal encephalocele). All had growth hormone deficiency, although one has attained normal height. One had diabetes insipidus. Two had hypogonadotropic hypogonadism. Prolactin secretion was elevated in one, normal in another, and borderline low in the third. Two patients were euthyroid, but in response to thyrotropin-releasing hormone (TRH) injection, one patient's thyrotropin (TSH) level increased to levels exceeding normal while the other's did not attain normal levels. In the third patient, TSH response to TRH went from subnormal to normal after treatment with growth hormone and thyroxine. No patient had evidence of ACTH deficiency. These heterogeneous findings do not permit assignment of an unequivocal anatomic or functional site to the endocrine defect(s). Pituitary function should be evaluated in all patients with basal encephalocele, and this entity should be considered in the differential diagnosis of central endocrine malfunction.

Adult↗
PubMed1977

Nonautonomy of parathyroid hormone and urinary cyclic AMP in primary hyperparathyroidism.

This study demonstrates that appreciable changes in serum parathyroid hormone and urinary cyclic AMP occur during experimentally induced hyper- and hypocalcemia in almost all patients with primary hyperparathyroidism regardless of histology. A single patient with tertiary hyperparathyroidism also demonstrated a significant elevation of serum parathyroid hormone and urinary cyclic AMP in response to EDTA induced reduction in ionized calcium. Thus, total autonomy of hormone secretion was not present in the great majority of the patients with a parathyroid adenoma, parathyroid hyperplasia, or the single patient with tertiary hyperparathyroidism. Therefore, preoperative evaluation of the rsponse of urinary cyclic AMP and serum parapthyroid hormone to EDTA or calcium infusion will not distinguish parathyroid adenomas from hyperplasia on the basis of total autonomy of hormone secretion. If a difference in secretory control is present between parathyroid adenomas and parathyroid hyperplasia, it is more subtle than total autonomy for adenomas and nonautonomy for hyperplasia.

Adenoma↗
PubMed1977

Comparison of clofibrate and chlorpropamide in vasopressin-responsive diabetes insipidus.

Six patients with vasopressin-responsive diabetes insipidus (DI) received clofibrate and chlorpropamide, singly and in combination. Decrease in urinary output averaged (mean +/- SEM): (1) clofibrate 2 g/day, 47% +/- 6%; (2) chlorpropamide 250 mg/day 59% +/- 5%; (3) clofibrate 2 g/day plus chlorpropamide 125 mg/day, 54% +/- 7%; (4) clofibrate 2 g/day plus chlorpropamide 250 mg/day 61% +/- 4%. Water deprivation tests before and during treatment showed significantly higher basal, final, and peak urinary osmolalities (Uosm) and lower free water clearance (CH20) on chlorpropamide, singly and in combination: clofibrate raised Uosm less but significantly decreased CH2O. Water load tests before and during treatment showed that chlorpropamide, singly and in combination, markedly decreased maximal urinary flow, maximal CH2O, percentage water load excreted, and increased minimal Uosm; clofibrate significantly decreased maximal urinary flow and CH2O only. One patient responded only to combination therapy. Chlorporpamide caused serious hypoglycemia in three of six patients. Clofibrate had no significant side effects.

Adolescent↗
PubMed1975

Acromegaly. Treatment by transsphenoidal microsurgery.

Serum growth hormone levels, thyroid function, and adrenal function were measured before and after surgery in 16 of 17 acromegalic patients undergoing undergoing transnasal transsphenoidal microsurgery of the pituitary. Thirteen patients have been followed up for 12 to 24 months; three patients have been followed up for three to six months. Serum growth hormone levels decreased to less than 5 ng/ml in seven of nine previously untreated patients; thyroid and adrenal function were preserved in eight of these nine patients. In seven patients treated previously by other modes of therapy, growth hormone levels after transsphenoidal surgery decreased to less than 5 ng/ml in three, to between 5 and 10 ng/ml in three, and from 98 to 41 ng/ml in one. Preoperative adrenal function was normal in six of these seven patients and was preserved in four; thyroid function was normal in five patients preoperatively and was preserved in three. Transsphenoidal microsurgery appears to offer an effective means of lowering growth hormone levels and a possiblity of preserving any remaining normal pituitary function. It may be considered for initial treatment in selected patients in whom more rapid arrest of acromegaly is indicated.

Acromegaly↗