Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MTC”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1988

[A new lymph node imaging agent--99mTc-polyphase liposome oleatis (99mTc-plo)].

A new lymph node radio-imaging agent, technetium-99m polyphase liposome oleatis (99mTc-plo), has recently been developed. Polyphase liposome oleatis was labelled with radionuclide by stannous chloride method. The labelled rate was 90% or more as technically identified by thin layer chromatography, external gamma-camera imaging and radioautography. In animal experiment, 0.2-0.3 ml (0.2 mci) of the 99mTc-plo was injected subcutaneously into the toes web of rats. After half an hour, the regional lymph nodes of popliteal fossa were visualized very clearly. The imaging figures may keep their distinct shadow up to 24 hours. The tested rabbits were sacrificed 10 hours after 99mTc-plo injection for detecting various kinds of tissue and organ with a scintillation counter. The regional lymph nodes revealed the highest uptake rate of the new agent, 12,116; 1,303; 1,615 times higher than that of the adjacent muscles, liver and spleen, respectively. In clinical experiment, 0.2-0.3 ml (0.5-0.8 mci) of the 99mTc-plo was injected subcutaneously into the toes web of patients. Half an hour later, the lymph nodes of inguinal, external iliac and common iliac regions appeared in sequence. If the new agent is injected perianally, the internal iliac lymph nodes will be seen. No side effect was observed in both types of experiment. This new agent has been tried in rats, rabbits and dogs with similar positive results. The new lymph node imaging technique is simple, safe, reliable and reproducible. This agent, being directed toward the lymph nodes and possessing affinity to cancer cells, is expected to be supplementary method to CT and B-ultrasonography for detecting lymphoid malignancy and lymph node metastasis.

Animals↗
PubMed2000

Medullary thyroid carcinoma: clinical characteristics, treatment, prognostic factors, and a comparison of staging systems.

BACKGROUND: The clinical courses of patients with medullary thyroid carcinoma (MTC) vary, and a number of prognostic factors have been studied, but the significance of some of these factors remains controversial. METHODS: The study group consisted of 104 patients with MTC or C-cell hyperplasia managed at the hospitals of the University of California, San Francisco, between January 1960 and December 1998. Patients were classified as having sporadic MTC, familial non-multiple endocrine neoplasia (MEN) MTC, MEN 2A, or MEN 2B. The TNM, European Organization for Research and Treatment of Cancer (EORTC), National Thyroid Cancer Treatment Cooperative Study (NTCTCS), and Surveillance, Epidemiology, and End Results (SEER) extent-of-disease stages were determined for each patient. The predictive values of these staging or prognostic scoring systems were compared by calculating the proportion of variance explained (PVE) for each system. RESULTS: Fifty-six percent of the patients had sporadic MTC, 22% had familial MTC, 15% had MEN 2A, and 7% had MEN 2B. The overall average age at diagnosis was 38 years, and patients with sporadic MTC presented at an older age (P < 0.05). Thirty-two percent of the patients with hereditary MTC were diagnosed by screening (genetic and/or biochemical). These patients had a lower incidence of cervical lymph node metastasis (P < 0.05) and 94.7% were cured at last follow-up (P < 0.0001) compared with patients not screened. Patients with sporadic MTC who had systemic symptoms (diarrhea, bone pain, or flushing) had widely metastatic MTC and 33.3% of those patients died within 5 years. Overall, 49.4% of the patients were cured, 12.3% had recurrent MTC, and 38.3% had persistent MTC. The mean follow-up time was 8.6 years (median, 5.0 years) with 10.7% (n=11) and 13.5% (n=14) cause specific mortality at 5 and 10 years, respectively. Patients with persistent or recurrent MTC who died of MTC lived for an average of 3.6 years (ranging from 1 month to 23.7 years). Patients who had total or subtotal thyroidectomy were less likely to have persistent or recurrent MTC (P < 0.05), and patients who had total thyroidectomy with cervical lymph node clearance required fewer reoperations for persistent or recurrent MTC (P < 0.05) than patients who underwent lesser procedures. In univariate analysis, age, gender, clinical presentation, TNM stage, sporadic/hereditary MTC, distant metastasis, and extent of thyroidectomy were significant prognostic factors. Only age and stage, however, remained independent prognostic factors in multivariate analysis. The TNM, EORTC, NTCTCS, and SEER staging systems were all accurate predictors of survival, but the EORTC prognostic scoring system had the highest PVE in this cohort. CONCLUSIONS: Screening for MTC and early treatment (total thyroidectomy with central neck lymph node clearance) had nearly a 100% cure rate. Patients with postoperative hypercalcitoninemia without clinical or radiologic evidence of residual tumor after apparently curative surgery may enjoy long term survival but have occult MTC. Only patient age at presentation and TNM stage were independent predictors of survival. The EORTC criteria, which included the greatest number of significant prognostic factors in our cohort, had the highest predictive value.

Adult↗
PubMed2004

Diagnosis and management of medullary thyroid carcinoma.

Successful treatment of MTC depends heavily on early diagnosis and treatment. Often, this is not possible for sporadic MTC; however, genetic testing for hereditary MTC makes this possible if genetic carriers have surgery before C cells undergo malignant transformation. All patients who have MTC should be tested for RET mutations, including putative sporadic cases. The leukocytes of suspected carriers and sporadic MTC cases should be tested for MEN2-associated germ-line mutations by polymerase chain reaction amplification of the appropriate RET gene exons, including 10, 11,13, 14, 15, and 16 (see Table I). When a RET mutation is found, all first-degree relatives must be screened to determine which individuals carry the gene. If these exons are negative, the other 15 should be sequenced because a small risk of hereditary MTC remains if no germ-line mutation is found. The probability that a first-degree relative will inherit an autosomal dominant gene for MTC from an individual who has sporadic MTC in whom no germ-line mutation is found is 0.18% . Patients who have MEN2B or RET codon 883 or 918 mutation should have a total thyroidectomy within the first 6 months of life, preferably within the first month of life. Patients who have 634 mutations, which account for approximately 70% of all MTC mutations, should undergo thyroidectomy by age 5 years. The recommendations for the timing of prophylactic thyroidectomy are not consistent for the less common mutations (see Table 2). There is a balance between performing prophylactic thyroidectomy earlier than at the youngest age at with MTC has been reported to occur for a specific RET mutation (see Fig. 3 and Table 2) and the complications of thyroidectomy, including permanent hypoparathyroidism and laryngeal nerve damage. Preoperative measurement of plasma free metanephrine and neck ultrasonography always should be done if the diagnosis of MTC is known preoperatively. Initial treatment of MTC is total thyroidectomy, regardless of its genetic type or putative sporadic nature, because surgery offers the only chance for a cure. Treatment with 1311 has no place in the management of MTC. Plasma CT measurements provide an accurate estimate of tumor burden and are especially useful in identifying patients who have residual tumor. Pentagastrin- or calcium-stimulated plasma CT testing is useful in identifying CCH or early MTC in carriers of RET mutations that are associated with late onset MTC. Pheochromocytoma may occur before or after MTC and is an important cause of mortality, even in young patients. HPT is an important aspect of MEN2A and requires surgery according to current guidelines for the management of primary HPT. Early thyroidectomy and appropriate management of pheochromocytoma clearly have modified the course of this disease, but more research is necessary in kindreds who have rare MTC mutations. Moreover, new treatments for widespread MTC are necessary because current chemotherapy agents offer little benefit. New drugs that lock the action of tyrosine kinase offer some hope.

Carcinoma, Medullary↗
PubMed1996

A method to communicate patient preferences about medically indicated life-sustaining treatment in the out-of-hospital setting.

OBJECTIVE: Patient preferences for life-sustaining treatment are frequently unknown at critical moments, which often results in clinicians providing treatment that is not medically indicated and/or may not be consistent with patient desires. A consortium of Oregon health care professionals developed the Medical Treatment Coversheet (MTC) to standardize documentation of patient preferences in the out-of-hospital setting by having corresponding physician orders available at the patient's location. We describe a unique process of development, evaluation, and implementation of the MTC. DESIGN: First, we conducted focus groups of providers to help draft the MTC. Second, the accuracy of MTC interpretation was determined by cohorts of acute and long-term care providers by indicating their treatment approach to three hypothetical written scenarios. They responded to the same scenarios twice, with and without the MTC. Responses were compared with each other and with ideal responses (most medically appropriate and in agreement with patient preferences) as defined by an expert panel. Finally, we are instituting pilot projects and developing a plan for statewide voluntary implementation of the MTC. SETTING: Urban and rural long-term care facilities and emergency medical service systems in Oregon. PARTICIPANTS: Focus groups included 28 general internists practicing in urban and rural settings and five nurses working in a long-term care facility. In addition, 87 providers (19 primary care physicians, 20 emergency physicians, 26 paramedics, and 22 long-term care nurses) participated in the evaluation of the form by responding to hypothetical scenarios. Providers in long-term care facilities in both an urban and rural area helped with pilot implementation of the MTC. Use of the MTC in noninstitutional settings was not evaluated. MAIN OUTCOME MEASURES: Suggestions from focus groups were incorporated into the form. For the hypothetical scenario responses, ideal appropriateness scores were analyzed, with a total possible score of 30 for each acute care provider and 15 for each long-term care provider. Statistically significant differences were determined using a paired t test. We report the experience of providers who helped with the pilot implementation of the form. RESULTS: Focus groups would use the MTC and believed it would be useful for their patients. Comparing responses to the hypothetical scenarios without the MTC to those with the MTC, 37% of treatment decisions changed for acute care and 29% changed for long-term care providers. Changes were attributable overwhelmingly to withholding treatments consistent with patient preferences. Compared with the ideal, decisions were more appropriate for all specific treatments across all scenarios and clinician groups with the MTC, with one exception: some advanced emergency treatments were withheld inappropriately by 18% of acute care providers with the MTC, (chi-square = 15.94, P < .0001). For all scenarios combined, appropriateness scores increased significantly with the MTC for both acute care (16.4 to 22.3, P < .0001) and long-term care providers (8.8 to 12.2, P < .0001). Overall, providers helping with the pilot implementation were satisfied with the document, organizational endorsements, and available informational resources. CONCLUSION: We describe our process for development, initial evaluation, and implementation of the MTC. In clinical scenarios overall, the MTC improves the appropriateness of clinicians' decisions about life-sustaining treatments. We are planning statewide implementation of the MTC after appropriate education of clinicians.

Advance Care Planning↗
PubMed1998

Sporadic medullary microcarcinoma of the thyroid: a retrospective analysis of eighty cases.

Clinical characteristics and prognosis of 80 patients (53 women and 27 men) with sporadic medullary thyroid carcinomas (MTC), less than 1 cm in size (micro-MTC), operated on between 1971 and 1996 are reported (73 total and 7 partial thyroidectomies). These patients, obtained from a national database of 899 patients with MTC, were compared with 357 cases of sporadic MTC greater than 1 cm and 149 subjects with familial MTC less than 1 cm (familial micro-MTC). Median age at surgery was 52.5 years, a distribution similar to larger sporadic MTC. Micro-MTC was identified due to elevated calcitonin (47.5%), clinically identified lymph node (10.0%), distant metastases (6.3%) or pathologic finding at surgery (36.2%). Diarrhea and/or flushing were observed in 6 patients including 4 with clinically identified lymph node. Among patients who had lymph node dissection at surgery (68.8%), lymph node involvement with tumor was observed in 30.9%, and was significantly more frequent in multifocal (7/11) than in unifocal micro-MTC (p < 0.03). All sporadic micro-MTC were unilateral. Survival rate was 93.9% +/- 4.4% (SE) at 10 years, greater than that observed in sporadic macro-MTC (p = 0.04). Normal postoperative basal calcitonin (CT) was obtained in 71.1% of micro-MTC patients versus 33.6% in sporadic macro-MTC (p < 0.01). Sporadic micro-MTC is much more frequent than expected, 15% of MTC in our series. Although specific survival rate and percentage of biological cure in micro-MTC are significantly better than for larger tumors, the frequency of lymph node involvement, however, justifies an aggressive surgical approach including total thyroidectomy and bilateral central lymph node dissection.

Adolescent↗
PubMed2006

[Ultrastructural characteristics of malignant T cell in T cell lymphoma].

In order to investigate the ultrastructural features of malignant T cell (MTC) in bona marrow aspirate (BMA) from patients with T Cell Lymphoma, the antigen expression of MTC was analyzed by flow cytometry, and the ultrastructural features of MTC in BMA from 13 T-cell lymphoma patients with bone marrow involvement (BMI) were observed by transmission electron microscopy. The results indicated that the sizes of MTC were uneven in every patient and their diameter were between 12 and 28 microm, in 6 out of 13 cases sizes of MTC were slightly uneven but in 7/13 cases sizes of MTC were significantly uneven. The heterochromatin of MTC was less than that of normal T cell and nucleolus diameter was from 2 to 8 microm in all cases. The nuclear contour of MTC was strikingly irregular in 10 out of 13 cases. The MTC had plenty of cytoplasm in 8 out of 13 cases and displayed many microvilli or processes on MTC surface in 7 out of 13 cases, while MTC in 6 out of 13 cases contained more Golgi's apparatuses, secretary vacuoles, dense granules and intermediate filaments. In 8 out of 13 cases mitochondria apparently swelled. It is concluded that the size of MTC increase unevenly in all patients. MTC nuclear contour in most cases is irregular by folding, indenting, and twisting, which often correlated with arising of paranuclear intermediate filaments. Processes and microvilli on surface and Golgi's apparatus, secretary vesicles, dense granules as well as intermediate filament in cytoplasm of MTC develop synchronously, meanwhile, mitochondria of MTC strikingly swell in most cases.

Adolescent↗
PubMed1996

Medullary thyroid carcinoma in children with multiple endocrine neoplasia types 2A and 2B.

Recently it has become possible to identify persons who have multiple endocrine neoplasia (MEN) syndrome types 2A and 2B based on the presence of missense mutations in the RET protooncogene. Kindred members who have inherited these syndromes can be identified before clinical or biochemical evidence of medullary thyroid carcinoma (MTC) develops, the malignancy that occurs in all affected patients. It is not known whether prophylactic removal of the thyroid gland early in childhood, based on a positive genetic test result, has a better clinical outcome than that associated with thyroidectomy after MTC is diagnosed clinically or biochemically. The authors' goal was to determine the long-term outcome for patients with MEN 2A and 2B who had thyroidectomy for MTC during childhood. These results were compared with those of patients who had prophylactic removal of the thyroid gland after the genetic diagnosis of MEN 2A was established. The hospital records of 49 children with MEN 2A or 2B were reviewed. Each patient had thyroidectomy for MTC before 16 years of age. The mean age at the time of operation was 10 years, and the mean follow-up period for those who had surgery before the availability of direct DNA genetic testing was 9.8 years. The indications for surgery included an elevated basal or stimulated plasma calcitonin level, a positive genetic test result, a thyroid mass, family history of MTC, or a phenotype diagnostic of MEN 2B. All children for whom the diagnosis of MEN 2A was established by direct genetic testing had thyroidectomy within the last 2 years. Of the 11 patients with MEN 2B who underwent thyroidectomy during childhood, 10 had MTC, and only 3 (27%) remain free of disease after the mean follow-up period of 11 years. One patient died, and seven are alive with persistent MTC. Among the 24 patients with MEN 2A who had their thyroid glands removed because of a family history of MTC or because of biochemical evidence of the disease, 5 (21%) have persistent or recurrent MTC after the mean follow-up period of 9.3 years. In four of these, the MTC was confined to the thyroid gland at the time of thyroidectomy. Of the 14 children who had thyroidectomy based on direct DNA testing, MTC was present in 11. Only four had elevated levels of stimulated plasma calcitonin before surgery. None had lymph node metastasis or surgical complications. The authors conclude that a significant number of patients with MEN 2A or 2B who undergo thyroidectomy in childhood for MTC have persistent or recurrent disease long-term. The genetic diagnosis of patients with these syndromes may allow for prophylactic surgery before the development of biochemical or clinical evidence of MTC. This approach is safe, but longer clinical follow-up will be necessary to confirm that MTC has been cured.

Adolescent↗
PubMed1992

Determination of magnetization transfer contrast in tissue: an MR imaging study of brain tumors.

OBJECTIVE: In this study, the magnetization transfer contrast (MTC) on MR images of several brain tumors and the correlation between MTC and tumors' histologic features were investigated. MTC depends on the extent of magnetization transfer, or cross-relaxation, from tissue water protons to macromolecular protons. On the basis of the known increase of the cross-relaxation rate with increasing molecular weight of protein in protein solutions, the hypothesis that changes in MTC correlate directly with the macromolecular composition of various tumors was tested. SUBJECTS AND METHODS: Preoperative MR images were obtained with a 0.1-T MR system in 40 patients with brain tumors. MTC was correlated with the histologic features and the dry weight of the tumors. The tumors studied included astrocytomas (10), acoustic schwannomas (three), meningiomas (12), pituitary adenomas (10), craniopharyngiomas (two), and hemangioblastomas (three). RESULTS: MTC was 0.43 in normal white matter and 0.42 in normal gray matter, and varied from 0.11 to 0.37 in the tumors. The mean MTC in astrocytomas (0.21 +/- 0.09) was smaller than the mean MTC in the gray matter (p = .0001) or in the other solid tumors (0.34 +/- 0.07 to 0.37 +/- 0.09, p < .002). MTC was larger in high-grade than in low-grade astrocytomas (0.28 +/- 0.05 vs 0.14 +/- 0.04, p = .0005). In meningiomas, MTC correlated with the collagen content of the tumor tissue (r = .95, p = .01). The differences in contents of solids between the solid tumor groups were not significant (p > or = .1, NS). CONCLUSION: When the previously demonstrated correlations between solid content and 1/T1 of the types of tumors studied are taken into consideration, the present results suggest a larger relative contribution from hydrodynamic vs cross-relaxation effects in astrocytomas than in benign tumors or in gray matter. The twofold difference in MTC between low- and high-grade astrocytomas probably reflects the amount of nuclear material in the tumor cells. Collagen content determined the differences in MTC among meningiomas. These results indicate that the major determinant of differences in MTC within these tumor groups is the high-molecular-weight tissue macromolecules, suggesting higher specificity for MTC than for T1 in discriminating between tissues on MR images.

Brain↗