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Biomedical subjects

M A Block

Publications and source records attributed to M A Block.

At least 73 records · Page 4Linked to original sources
PubMed1978

Management of occult medullary thyroid carcinoma: evidenced only by serum calcitonin level elevations after apparently adequate neck operations.

Following operation for medullary thyroid carcinoma, elevated serum calcitonin levels were present in 18 patients who had no clinically evident residual tumor. In eight of these patients, additional operations have been performed to achieve an appropriate thyroidectomy and cervical lymph node dissection. In six of these eight, elevated serum calcitonin concentrations persist. Extensive clinical examinations failed to identify a metastatic focus of carcinoma. Serum calcitonin concentrations have remained relatively stable for up to six years (average, 3.9 years) of observations in 12 patients after initial or only operations performed from one to 13 years (average 7.3 years) previously. This suggests that microscopic metastases of this carcinoma can remain relatively dormant for years. The management of medullary thyroid carcinoma requires initially adequate cervical operations, periodic serum calcitonin measurements postoperatively, reoperation if adequate neck surgery has not been performed and if serum calcitonin levels remain elevated and only periodic reevaluation for other asymptomatic patients with persistently elevated concentrations of serum calcitonin.

Calcitonin↗
PubMed1977

Multicellular origin of parathyroid "adenomas".

Most cases of primary hyperparathyroidism are associated with enlargement of a single gland (i.e., an "adenoma") or with chief-cell hyperplasia, but there is controversy about the relative frequency of each of these entities. It has even been postulated that adenomas do not arise spontaneously, bu- result from prolonged hyperplasia in response to unknown stimuli. We studied four parathyroid adenomas from three women with heterozygosity (GdB/GdA) for the X-chromosome-linked enzyme, glucose-6-phosphate dehydrogenase, to determine the number of cells from which the growths arise. Unicellular origin would be compatible with a rare oncogenic event, whereas multicellular origin might be seen with hyperplasia. Both B and A isoenzymes were found in each "adenoma" in proportions similar to those observed in normal tissues, indicating that the lesions have multicellular origin. Thus, parathyroid hyperplasia and adenomas, which at best are difficult to distinguish from one another pathologically, may also be similar biologically.

Adenoma↗
PubMed1977

Primary hyperparathyroidism. A cause of hypercalciuria and renal stones in patients with medullary sponge kidney.

Three patients with nephrolithiasis were found to have both medullary sponge kidney (MSK) and primary hyperparathyroidism. In all cases, urine calcium excretion returned to normal after parathyroidectomy. The passage of stones was abolished for more than 20 years in one case and for more than 12 years in another. The available data suggest that many patients with MSK are asymptomatic and that the risk of stone formation is increased by an associated metabolic abnormality such as hypercalciuria or hyperparathyroidism.

Adult↗
PubMed1977

Absence of pancreatic duct dilation in chronic pancreatitis: surgical significance.

Of 22 patients treated surgically for intractable pain from chronic alcoholic pancreatitis, eight did not show notable dilation of the main pancreatic duct by endoscopic retrograde cholangiopancreatography (ERCP), operative pancreatography, and/or operative and microscopical studies of the pancreas after subtotal pancreatectomy. In all patients, far advanced parenchymal pancreatitis was evident at operation and by microscopical study of the removed portion of the pancreas. These findings indicate that the basic problem in a considerable number of patients with symptomatic alcoholic chronic pancreatitis is not related primarily to obstruction with dilation of the major pancreatic duct, but to intrinsic changes in the parenchymal pancreas. The preoperative use of ERCP and individualization of operative procedures with a preference for subtotal or partial pancreatectomy for symptomatic chronic alcoholic pancreatitis are supported.

Adult↗
PubMed1977

Management of carcinoma of the thyroid.

Greater precision has developed in recent decades in the selection of patients for operation for thyroid nodules suspicious for malignancy and in adapting operative procedures to the extent and pathologic variety of the individual thyroid carcinoma, when present. A thyroid lobectomy is considered to be the minimal operative procedure usually indicated for a suspicious thyroid nodule or carcinoma involving one lobe of the thyroid gland. Factors determining the extent of operation for thyroid carcinoma include the pathologic variety, gross distribution of the malignancy, and health status of the individual patient. Total or near total thyroidectomy should be considered for all patients with thyroid carcinoma except for single occult carcinomas and unilateral low grade angio-invasive carcinomas. Removal of lymph nodes in regions adjacent to the thyroid carcinoma is advisable, lateral neck dissections being reserved for patients with palpable lymphadenopathy, demonstrated metastases to lateral cervical lymph nodes, or a poorly differentiated carcinoma likely to metastasize to these lymph nodes. A modified radical lymph node dissection is satisfactory except for those carcinomas invading muscles in the neck. Anatomic neck dissections provide a better prognosis than incomplete lymph node procedures for patients with regional lymph node metastases. Following operation, patients should receive thyroid hormone therapy, be evaluated for possible treatment with radioactive iodine or other therapeutic measures, and be followed for evidence of recurrent disease as well as thyroid and parathyroid function. Adequate early operation is preferred to late ultraradical procedures, from standpoints of morbidity and prognosis. Unfavorable prognostic factors include extensive gross disease, poorly differentiated carcinoma present as the entire lesion or as foci in a differentiated carcinoma, and age over 40. With adequate surgical treatment, the prognosis for operable thyroid carcinoma is good.

Carcinoma↗
PubMed1976

Primary diffuse microscopical hyperplasia of the parathyroid glands: surgical importance.

In two of 182 patients with verified primary hyperparathyroidism, microscopical hyperplasia was present in all parathyroid glands that were normal in size or only slightly enlarged. All parathyroid glands in another two patients showed microscopical hyperplasia and varied from a normal size of 190 mg. In seven additional patients, microscopical hyperplasia was present in one, several, or all parathyroid glands, which varied in weight from normal to 350 mg. Familial hyperparathyroidism or multiple endocrine neoplasia was evident in five of 11 patients. Contributing to difficulties was the experience in five patients in whom removal of mildly enlarged parathyroid glands corrected hypercalcemia, but definite microscopical abnormalities were not evident by routine histologic study of the glands. Thus, there appears to be a spectrum of abnormalities relative to size and microscopical changes in parathyroid glands of patients with primary hyperparathyroidism. The surgeon should be aware of these patterns of parathyroid hyperplasia that require a search for a fifth parathyroid gland and a subtotal parathyroidectomy.

Adult↗
PubMed1976

Geriatric primary hyperparathyroidism.

Primary hyperparathyroidism occurs in a significant number of patients over 60 years of age; about one-third of the 182 patients we studied were in this age group. Primary hyperparathyroidism has been recognized with greater frequency in recent years, particularly in patients without manifestations of renal lithiasis or osteitis fibrosa cystica and in older patients. Age alone is not critical in the occurrence of serious complications from hypercalcemia, the presence of other life-endangering disease, or the development of major postoperative complications in the management of primary hyperparathyroidism. A liberal but selective policy is advocated in advising operation for primary hyperparathyroidism in the elderly. Different clinical patterns of primary hyperparathyroidism are recognized in all age groups. The operative procedure for primary hyperparathyroidism is determined primarily by the surgeons at the time of operation, on the basis of gross characteristics of the parathyroid glands. A precise correlation is not found between microscopic changes, gross changes, and clinical features of primary hyperparathyroidism.

Aged↗
PubMed1975

Management of parathyroid glands in surgery for medullary thyroid carcinoma.

Of 13 patients treated surgically for familial medullary thyroid carcinoma in whom parathyroid tissue was availabe, the majority showed parathyroid abnormalities (hyperplasia in sis, tumors in five). Two patients had had renal calculi. No correlation was evident between the presence of the parathyroid tumors and peripheral blood levels of parathyroid hormone. Hyperparathyroidism is usually mild, but occasionally it results in complications of hypercalcemia. Hyperparathyroidism has not appeared to date following removal of medullary thyroid carcinoma associated with normal-sized but microscopically hyperplastic parathyroids. Evidence of parathyroid abnormalities has not been recognized in eight patients with sporadic medullary carcinoma, making genetic factors dominant in explaining the association of parathyroid hyperplasia and this carcinoma. At operation, parathyroid glands should be evaluated and those that are grossly enlarged removed while preserving parathyroid function.

Carcinoma↗
PubMed1975

Interpretative problems in endoscopic retrograde cholangiopancreatography.

1. Of forty-one patients with biliary tract problems studied by endoscopic retrograde choledochopancreatography, interpretation of ductograms or endoscopic observations in ten could not be accomplished with ease for one or several reasons. 2. Although incomplete filling of the bile ducts usually signifies organic obstruction, this occasionally is not true. The specific origin and histologic character of the lesion causing bile duct obstruction are not delineated by retrograde endoscopic cholangiography. 3. Other occasional limitations of endoscopic cholangiography include difficulties in demonstrating minute stones, in recognizing confusing anatomic variations, and in defining the status of recurrent strictures. 4. Inflammatory changes in the duodenal papilla can simulate carcinoma, or vice versa, on the basis of observation by the endoscopist. The capability of achieving a pancreatogram does not rule out the presence of carcinoma at the ampulla producing jaundice. Current technics for biopsy of the papilla or ampulla are in some instances inadequate, making results of such procedures unreliable. 5. Although endoscopic retrograde cholangiopancreatography frequently permits acquisition of vital information for the surgeon and occasionally provides unexpected information of significance, interpretative difficulties in some instances always necessitate the correlation of findings with other available clinical information.

Bile Ducts, Intrahepatic↗
PubMed1975

Management of primary hyperparathyroidism in the elderly.

Of 166 surgical patients for whom the diagnosis of primary hyperparathyroidism was established over a 20-year period, about one-third were over 60 years of age. For an additional 9 patients, or operation was advised, usually because of other life-endangering disease and the presence of only a mild degree of hypercalcemia without complications. In recent years, nearly 50 per cent of the patients did not have renal calculi or osteitis fibrosa cystica; this was unrelated to age. Most of the patients with management problems were seen since 1965. Age alone was not a dominant factor in relation to serious complications from hypercalcemia, the presence of other critical disease increasing the risk of operation, or the development of major postoperative complications. The only death from primary hyperparathyroidism occurred in a 74-year old patient who refused re-operation and died from an acute hypercalcemic crisis. A liberal, but selective, policy of surgical treatment is justified for primary hyperparathyroidism in the elderly. Patients for whom the diagnosis of primary hyperparathyroidism is established may be separated into three groups: those for whom early operation is indicated, those for whom operation should be delayed to permit recovery from other life-endangering acute disease, and those for whom operation is unjustified because of minimal uncomplicated hypercalcemia and other serious disease greatly limiting life expectancy. These categories encompass all age groups and are not restricted to the elderly. All patients require periodic re-evaluation.

Adult↗