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M H Wheeler

Publications and source records attributed to M H Wheeler.

At least 19 recordsLinked to original sources
PubMed1992

The relationship between adenoma weight and intact (1-84) parathyroid hormone level in primary hyperparathyroidism.

The relationship between preoperative serum levels of intact parathyroid hormone (PTH), serum calcium, and the weight of parathyroid adenoma has been investigated in 44 patients undergoing surgery for primary hyperparathyroidism due to single gland disease. There was no significant correlation between preoperative serum calcium and either intact PTH concentration or adenoma weight (r = 0.465 and 0.381, respectively). Although there was a significant correlation between PTH concentration and adenoma weight (r = 0.850, p less than 0.0005), this correlation was lost when two unusually heavy adenomas weighing 10.98 and 15.23 g were removed from the analysis. Clearly, a preoperative direct prediction of gland weight determined from PTH level was not possible. Patients with adenomata heavier than 750 mg had a significantly lower circulating PTH level per mg of adenoma than patients with glands lighter than 750 mg. PTH secretion in vitro in low calcium medium by adenoma cells from glands weighing less than 1 g was higher than secretion by cells from adenomas heavier than 1 g. Larger parathyroid adenomata appear to secrete less PTH per unit weight in vivo and per unit cell in vitro under conditions of maximal stimulation.

Adenoma↗
PubMed1990

Normalization of thyroid blood flow in Graves' hyperthyroidism following radioactive iodine therapy.

In a group of 12 patients with Graves' hyperthyroidism, administration of 514 +/- 43 (mean +/- SD) MBq iodine-131 was associated with a fall of superior thyroid artery (STA) blood flow in two at 6 months and in eight at 11 months. The reduction in time-averaged velocity at 11 months correlated with the reduction in FT4 (r = 0.72, P less than 0.01) and in FT3 (r = 0.64, P less than 0.025) at this time. In four patients who had persistent elevated STA blood flow, two were still hyperthyroid. The diameter of the STA was unchanged at 6 months and only half the patients had reduction of their STA size at 11 months after radioiodine (RAI) therapy. These data indicate that normalization of STA blood flow precedes normalization of STA size in patients treated with RAI. Further work is required to determine whether STA blood flow measurements are of predictive value in treatment outcome.

Aged↗
PubMed1988

Secretion of intact PTH by dispersed human hyperparathyroid cells.

The rate of secretion of intact PTH by cells dispersed from adenomatous and hyperplastic human parathyroid tissue was measured using a two-site immunochemiluminometric assay specific for the intact peptide. Secretion rates were monitored following incubation in high and low-calcium media. The mean rate of secretion from hyperplastic cells was significantly greater (P less than 0.05) at low calcium and significantly more suppressible at high calcium (P less than 0.01) compared with adenomatous cells. These studies have demonstrated: (1) the calcium-dependent secretion of intact PTH, (2) that intact hormone release contributes to the non-suppressible component of secretion, and (3) differences in the secretory characteristics of adenomatous and hyperplastic parathyroid cells.

Adenoma↗
PubMed1987

The effect of preoperative Lugol's iodine on thyroid blood flow in patients with Graves' hyperthyroidism.

A study was conducted to investigate the effect of Lugol's iodine on the superior thyroid artery (STA) blood flow with use of a Duplex ultrasound scanner for 12 patients with Graves' disease. All patients were treated with antithyroid drugs until they were euthyroid and then, with randomization, the patients received either Lugol's iodine, 0.3 ml thrice daily, or placebo for 9 days in a double-blind fashion. Antithyroid drugs were continued throughout the study. Reduction in the diameter, time-averaged velocity (TAV), and volume flow (VF) of the STAs was demonstrated in all patients in the treatment group, whereas there were no consistent trends in the placebo group. The changes in TAV and VF were significantly different between the placebo and treatment groups (p less than 0.01 for TAV and p less than 0.005 for VF). These changes were more marked in patients with high initial VF and minimal in patients with low initial VF. On the basis of these results, we recommend that patients with high thyroid blood flow before thyroidectomy should receive Lugol's iodine preoperatively.

Adult↗
PubMed1987

Studies in patients with hyperparathyroidism using a new two-site immunochemiluminometric assay for circulating intact (1-84) parathyroid hormone.

A recently developed chemiluminescent immunoassay for 1-84 intact parathyroid hormone (PTH) demonstrated increased specificity by virtue of two-site antibody binding and increased sensitivity by use of a chemiluminescent technique. Basal PTH levels were measured in three groups of subjects: (1) normal (n = 82), (2) hyperparathyroidism (n = 31), and (3) patients with hypercalcemia of malignancy (n = 16). There was good discrimination between normal (1.2 to 9.4 pmol/L) and hyperparathyroid subjects (9.2 to 53.4 pmol/L). In persons with hypercalcemia of malignancy all PTH levels were within the normal range (0.8 to 5.2 pmol/L) or suppressed. PTH release was stimulated by the intramuscular injection of 100 IU salmon calcitonin in 6 normal controls, 10 patients with primary hyperparathyroidism due to adenoma, and 5 with four-gland hyperplasia. There was no significant rise in PTH concentration and out of the normal range in the control subjects, but the adenoma patients demonstrated a mean rise of 24.4%, 26%, and 33%, and hyperplasia patients, a mean rise of 37%, 47%, and 37% over basal levels at 120, 180, and 240 minutes. The mean absolute rise in PTH concentration was 13.4 +/- 7.7 pmol/gm of parathyroid tissue in the adenomas and 27.2 +/- 9.5 pmol/gm of parathyroid tissue in the hyperplastic glands; this difference was significant (p less than 0.05). Serial blood samples from a central vein were taken at surgery for hyperparathyroidism, and the rate of decay of the intact hormone was studied in 9 patients after removal of the parathyroid tissue. This decay was rapid with a half-life of 300 seconds. We conclude that this new specific and sensitive intact PTH assay will provide a valuable means of investigating dynamic aspects of parathyroid physiology.

Adult↗
PubMed1986

Thyroid follow-up.

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Follow-Up Studies↗