Melvin A. Block, MD.
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History, 20th Century↗
Biomedical subjects
G B Talpos
Publications and source records attributed to G B Talpos.
Primary hyperparathyroidism and associated neoplasms.
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Adult↗
Localization of residual medullary thyroid cancer by thallium/technetium scintigraphy.
Whole-body thallium/technetium subtraction scintiscans, with thallium 201 chloride and technetium 99m pertechnetate, were obtained on 10 patients with medullary thyroid cancer with postoperative elevations of serum calcitonin values. Seven patients had the hereditary variant of medullary thyroid cancer (the multiple endocrine neoplasia, type II syndrome) while three patients had the sporadic form. Negative scans were obtained on five patients with basal calcitonin levels less than 3 ng/ml (normal less than 0.35 ng/ml). Five other patients with elevated calcitonin levels (range 3.6 to 69.2 ng/ml; mean 28.3 ng/ml) had positive scans that have guided further surgical approaches. Serum calcitonin appears to remain the most sensitive indicator of residual medullary thyroid cancer while localization of this residual tumor tissue frequently can be obtained through thallium/technetium subtraction imaging in both the hereditary and sporadic forms of the disease.
Adolescent↗
Clinical value of tumor doubling estimations in multiple endocrine neoplasia type II.
Experience with children with multiple endocrine neoplasia (MEN) type IIb has emphasized that medullary thyroid cancer (MTC) in MEN IIb is more aggressive than in MEN IIa. Earlier ages of onset and apparently more rapid growth of MTC in MEN IIb suggest that these tumors have earlier ages of conversion to malignant states and/or shorter doubling times. The age at which a hyperplastic C cell becomes a malignant cell and the true doubling time cannot be estimated presently. Maximum volume-doubling times of 35 and 75 days (21 to 26 doublings) were calculated from tumor size and age at operation in five patients with MEN IIb aged 2 to 5 years. Calculations in 20 patients with MEN IIa revealed maximum doubling times of 110 to 440 days, with ages ranging from 7 to 29 years and number of doubling ranging from 18 to 38. Positive provocative calcitonin tests in two adult patients with MEN IIa after 10 to 11 years of repeated negative tests suggest a minimum doubling time of 190 to 210 days. Such experience emphasizes that negative stimulated calcitonin tests less than 11 years after operation do not provide assurance of cures for MTC in MEN IIa although negative tests after more than 5 years for MEN IIb are encouraging. Calculations of volume doublings accounting for various-sized tumors are compatible with Knudson's two-mutational-event theory on the initiation of neoplasia.
Adolescent↗
Phenotype mapping of the multiple endocrine neoplasia type II syndrome.
The multiple endocrine neoplasia (MEN) IIb syndrome has been differentiated from MEN IIa by the presence of various phenotypic characteristics such as mucosal neuromas, marfanoid habitus, congenital skeletal anomalies, and prominent corneal nerves, as well as the lack of parathyroid involvement. Analysis of a kindred with some characteristics of both syndromes (including an associated chromosomal deletion) tends to unify the MEN II syndromes as a single disorder with variable expressivity. The linear map of the genetic determinants is postulated to conform with the following phenotype order: parathyroid tumors, medullary thyroid cancer, pheochromocytomas, skeletal changes, prominent corneal nerves, mucosal neuromas, and marfanoid habitus. Appreciation of this sequence can allow earlier identification and treatment of affected individuals.
Acetabulum↗
The clinical course after definitive operation for medullary thyroid carcinoma.
Thorough family studies that used the radioimmunoassay procedure for calcitonin (CT) during the past 12 years have provided data on 70 patients from 12 kindreds with hereditary medullary thyroid cancer (hereditary group) and 28 patients with sporadic or nonhereditary medullary thyroid cancer (sporadic group). Serum CT elevations after total thyroidectomy as evidence of residual tumor have been encountered in 21 of 25 patients in the hereditary group with palpable tumors preoperatively (84%) and in 13 of 24 in the sporadic group (54%). However, none of 26 patients with hereditary nonpalpable lesions found by family screening studies have been found to have postoperative CT elevations. Both cervical lymphadenectomy in patients with lymph node involvement at initial operation and reexploration in those with CT elevations after total thyroidectomy have been unsuccessful in the eradication of metastatic disease. These data emphasize the value of thorough family studies that use stimulated CT measurements in the detection of early and curable neoplasms. Involvement of the parathyroid glands or the adrenal medulla that occurred in the hereditary multiple endocrine neoplasia syndromes varied from family to family; it influenced the clinical course and required regular surveillance with calcium and catecholamine studies. Separation of hereditary from sporadic cases has practical value in the identification of family members at risk and also in the provision of prognostic data.
Adult↗
Management of primary hyperparathyroidism: report on a workshop.
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Humans↗
Pheochromocytoma in multiple endocrine neoplasia type II: an example of the two-hit theory of neoplasia.
Six kindreds in which pheochromocytomas were present as manifestations of the autosomal dominantly inherited multiple endocrine neoplasia (MEN) type II were studied. The patients underwent bilateral total adrenalectomy with the finding that the pheochromocytomas were bilateral, multifocal, and associated with distinct medullary hyperplasia and reduction in the normal corticomedullary ratio-- features not usually seen in patients with sporadic pheochromocytoma. These findings were exemplified in recent cases of a 34-year-old woman and a 40-year-old man who both had undergone total thyroidectomy for medullary carcinoma of the thyroid. Diagnoses of pheochromocytoma were made by catecholamine studies, computerized tomography, and 131I meta-iodobenzylguanidine (MIBG) scan. Bilateral adrenalectomy was performed with the finding of multiple bilateral pheochromocytomas and adrenal medullary hyperplasia. As in hereditary medullary carcinoma of the thyroid, the histologic findings in pheochromocytomas of the MEN II syndrome are consistent with Knudson's two-mutational-event theory for the initiation of neoplasia, with adrenal medullary hyperplasia representing the manifestation of the first or genetic mutational event and being present invariably in the hereditary cases.
Adrenal Gland Neoplasms↗
Internal thoracic vein cannulation as a complication of central venous catheterization.
Central venous catheterization is utilized in resuscitation and evaluation of the severely ill patient. It is also employed for total parenteral nutrition. The list of potential complications is extensive and includes catheter malposition, with its attendant morbidity, as the most frequent complication. Inaccurate venous pressure measurements and mediastinal phlebitis have been cited as natural sequelae of inadvertent catheterization of the internal thoracic (mammary) vein (ITV). The histories of four patients who had ITV cannulation are analyzed as to indications for central venous catheterizations, site of insertion, time of delayed recognition, and attendant complications. In addition, the records of 150 consecutive patients who underwent central venous line placement were reviewed to determine the number of lines placed (242), the number and percentage of postcatheterization chest films obtained with standard posterior-anterior (P-A) and lateral technique (70, 29%), the number and incidence of catheterization-associated complications (78, 32%), and the number and incidence of ITV cannulation (5, 2%). No untoward results were seen as a result of this complication in the nine patients discovered, although the potential for morbidity was present. Subtle changes on portable chest films and standard technique P-A and lateral films remain the best protection against complications associated with ITV cannulation.
Adult↗
Computed tomographic evaluation of intrathoracic thyroid malignancy.
As only a few cases of intrathoracic thyroid malignancy with computed tomographic (CT) examination have been described, we reviewed the CT examinations of three patients with primary and five patients with recurrent thyroid malignancy involving the thorax. Irregular border of the thyroid mass, extension of tumor mass into mediastinal fat or chest wall, or lymphadenopathy suggested the malignant nature of the primary tumor. CT examination in recurrent disease demonstrated mediastinal, hilar and retrocrural adenopathy, compression of major vessels with collateral flow, pulmonary and bony metastases. CT was of value both in identifying the extent of disease and documenting response to treatment.
Adenocarcinoma↗