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64 result(s) for "Obara, Takao"
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Epidemiological study of gastroenteropancreatic neuroendocrine tumors in Japan
Background There have been few epidemiological studies on gastroenteropancreatic neuroendocrine tumors (GEP-NETs) in Japan. Methods We examined the epidemiology of GEP-NETs [pancreatic endocrine tumors (PETs) and gastrointestinal neuroendocrine tumors (GI-NETs)] in Japan in 2005 using a nationwide stratified random sampling method. Results A total of 2,845 individuals received treatment for PETs. Prevalence was estimated as 2.23/100,000 with an annual onset incidence of 1.01/100,000. Non-functioning tumor (NF)-PET constituted 47.4%, followed by insulinoma (38.2%) and gastrinoma (7.9%). Distant metastases were reported in 21% patients with NF-PETs and occurred more frequently as tumor size increased (>2 cm). Multiple endocrine neoplasia type 1 (MEN-1) was detected in 10% of PETs but only in 6.1% of NF-PETs. NF-PETs were detected incidentally by physical examination in 24% patients. In 2005, an estimated 4,406 patients received treatment for GI-NETs. Prevalence was estimated as 3.45/100,000, with an annual onset incidence of 2.10/100,000. The locations of GI-NETs varied: foregut, 30.4%; midgut, 9.6%; and hindgut, 60.0%. Distant metastases were observed in 6%. Lymph node metastases occurred more frequently as tumor size increased (>1 cm). The frequency of MEN-1 complications was 1%. Physical examination revealed GI-NETs in 44% patients. The frequency of symptomatic GI-NETs was 3.4%. Interestingly, 77.1% of patients with foregut GI-NETs had type A gastritis. Conclusion Our results show there are large differences in GEP-NETs between Japan and Western nations, primarily due to differences in the presence of MEN-1 in NF-PETs and the location, symptomatic status, and prevalence of malignancy in GI-NETs.
Parathyroid Carcinoma: Etiology, Diagnosis, and Treatment
Background The goal of the present study was to make our medical practice evidence-based for patients with parathyroid carcinoma. Methods We posed six clinical questions relevant to the management of parathyroid cancer. A comprehensive search and critical appraisal of the literature was then carried out. Results Most of the literature retrieved was retrospective in design and differed in the definition of carcinoma. The distinction between unequivocal and equivocal carcinoma (or atypical adenoma) was not always made for the study populations. None of the studies indicated reproducibility of outcome measures. Of the histopathological features described in the literature based on the description of Schantz and Castleman, capsular/vascular invasions and trabecular growth pattern were the most specific, and fibrous bands were the most sensitive. None of the patients with “atypical adenoma” developed recurrence, whereas 25% of those with “equivocal carcinoma” did. Mutations in HRPT2 , the gene responsible for hereditary hyperparathyroidism with jaw-tumor syndrome, were strongly associated with sporadic parathyroid carcinoma. Severe hypercalcemia and its related clinical symptoms, extremely high levels of parathyroid hormone, osteitis fibrosa cystica, a palpable neck mass, and a relatively large depth–width ratio on ultrasonography, are the important features of parathyroid carcinoma. Disease-specific survival rates reported in the literature were varied, reflecting the differences in the definitions of carcinoma, study populations, and interventions. Conclusions To establish valid evidence for patient management in the future, a collaboration of endocrine specialists is essential to conduct well-designed clinical studies for this rare disease.
A case of Turner’s syndrome with Graves’ disease and primary hyperparathyroidism
We report a 21-year-old woman with Turner’s syndrome, Graves’ disease and primary hyperparathyroidism. At 12 years of age, she was of short stature, and was diagnosed with Turner’s syndrome and treated with growth hormone. At the age of 17 years, she was diagnosed with Graves’ disease. On treatment with methimazole, her laboratory findings normalized. At the age of 20 years, her serum calcium and intact parathyroid hormone levels were high. The upper left parathyroid gland showed swelling and was resected, and adenoma was diagnosed pathologically. Then, primary hyperparathyroidism induced by the adenoma was diagnosed. After the parathyroidectomy, the patient’s serum calcium and intact parathyroid hormone levels normalized. Is likely that Turner’s syndrome and Graves’ disease were not associated with primary hyperparathyroidism. Multiple endocrine neoplasia type 1 was unlikely considering the clinical, laboratory, ultrasonographic, and scintigraphic findings.
Preliminary results of a Japanese nationwide survey of neuroendocrine gastrointestinal tumors
We conducted a nationwide survey to estimate the incidence of neuroendocrine gastrointestinal tumors (NETs) newly diagnosed in Japan from 2002 through 2004. Data on 1541 patients, 514 pancreatic endocrine tumors (PETs) and 1027 gastrointestinal carcinoids (GICs), were collected and analyzed. Nonfunctioning tumors (NF-PET) constituted 47.7% of PETs. Next in frequency were insulinoma (31.7%) and gastrinoma (8.6%). Malignancy was frequent in NF-PETs (46.1%) and gastrinomas (45.5%), but only 7.4% of insulinomas were malignant. The incidence of multiple endocrine neoplasia type-1 associated with PETs was 7.4%. The incidence of GICs was 28.8%, 5.2%, and 66.0% in foregut, midgut, and hindgut, respectively. Carcinoid syndrome and metastases were observed in only 1.7% and 5.6% of GICs, respectively. The incidence of NETs in Japan was clarified by this preliminary study. Comparatively large differences in GICs between Japan and Western nations were present with regard to the location, symptomatic status, and prevalence of malignancy.
Bone Mineral Density Before and After Surgical Cure of Cushing’s Syndrome Due to Adrenocortical Adenoma: Prospective Study
Osteoporosis is a major complication of Cushing’s syndrome. The aim of the present study was to assess the chronologic effect of surgical cure on bone mineral density (BMD) in patients with Cushing’s syndrome due to adrenal adenoma. BMD was examined in 28 patients before laparoscopic adrenalectomy; 17 patients with reduced BMD were then included in the longitudinal evaluation. BMD was determined using dual energy X-ray absorptiometry (DXA) before and at 3, 6, 12, 18, and 24 months after adrenalectomy. The prevalence of osteoporosis was 64% (95% confidence interval 44–81%). Preoperative BMD of the lumbar spine in the lateral projection was significantly lower than that of the femoral neck (mean ± SD score: −3.53 ± 0.75 vs. −1.54 ± 0.22, p  = 0.003). A significant increase in BMD was observed at 3 months after surgery in the lumbar spine ( p  = 0.0004). Improvement at both sites was maintained at 24 months after surgery. The postoperative percentage change in BMD of the lumbar spine was significantly higher than that of the femoral neck (mean ± SD 36.7% ± 26.5% vs. 11.2% ± 12.1%, p  = 0.01). The change in the seven premenopausal patients was significantly higher than that in the three postmenopausal patients ( p  = 0.0006). Surgical cure of hypercortisolism provides significant improvement in BMD in patients with Cushing’s syndrome due to adrenal adenoma. The improvement is particularly apparent in the lumbar spine measured in the lateral projection. Premenopausal women are more likely to benefit from surgery in terms of secondary osteoporosis.
Genome-Wide and Locus Specific Alterations in CDC73/HRPT2-Mutated Parathyroid Tumors
Mutations in the hyperparathyroidism type 2 (HRPT2/CDC73) gene and alterations in the parafibromin protein have been established in the majority of parathyroid carcinomas and in subsets of parathyroid adenomas. While it is known that CDC73-mutated parathyroid tumors display specific gene expression changes compared to CDC73 wild-type cases, the molecular cytogenetic profile in CDC73-mutated cases compared to unselected adenomas (with an expected very low frequency of CDC73 mutations) remains unknown. For this purpose, nine parathyroid tumors with established CDC73 gene inactivating mutations (three carcinomas, one atypical adenoma and five adenomas) were analyzed for copy number alterations and loss of heterozygosity using array-comparative genomic hybridization (a-CGH) and single nucleotide polymorphism (SNP) microarrays, respectively. Furthermore, CDC73 gene promoter methylation levels were assessed using bisulfite Pyrosequencing. The panel included seven tumors with single mutation and three with double mutations of the CDC73 gene. The carcinomas displayed copy number alterations in agreement with previous studies, whereas the CDC73-mutated adenomas did not display the same pattern of alterations at loci frequently deleted in unselected parathyroid tumors. Furthermore, gross losses of chromosomal material at 1p and 13 were significantly (p = 0.012) associated with parathyroid carcinomas as opposed to adenomas. Quantitative PCR-based copy number loss regarding CDC73 was observed in three adenomas, while all the carcinomas were diploid or showed copy number gain for CDC73 gene. Hypermethylation of the CDC73 gene promoter was not observed. Our data could suggest that CDC73-mutated parathyroid adenomas exhibit a partly unique cytogenetic profile in addition to that of carcinomas and unselected adenomas. Furthermore, CDC73-mutated carcinomas displayed losses at 1p and 13 which are not seen in CDC73-mutated adenomas, making these regions of interest for further studies regarding malignant properties in tumors from CDC73-mutated cases. However, due to the small sample size, validation of the results in a larger cohort is warranted.
Stimulating parathyroid cell proliferation and PTH release with phosphate in organ cultures obtained from patients with primary and secondary hyperparathyroidism for a prolonged period
The pathogenesis of primary hyperparathyroidism (I°-HPT) and secondary hyperparathyroidism (II°-HPT) remains to be elucidated. To characterize their pathophysiology, we investigated the effects of calcium and phosphate on cell proliferation and PTH release in an organ culture of parathyroid tissues. Dissected parathyroid tissues obtained from patients with I°-HPT (adenoma) or II°-HPT (nodular hyperplasia) were precultured on a collagen-coated membrane for 1-4 week. After changing the medium for one containing various concentrations of phosphate, PTH release and [³H]thymidine incorporation were studied. In contrast to dispersed parathyroid cells cultured in a monolayer, calcium decreased PTH release in a concentration-dependent manner in parathyroid tissues. Furthermore, when parathyroid tissues obtained from II°-HPT were precultured for 1-4 weeks, PTH release and parathyroid cell proliferation were significantly increased in high-phosphate medium. These phosphate effects were also observed to a lesser extent in parathyroid tissues obtained from I°-HPT, but there was no significant difference between I°-HPT and II°-HPT. Microarray analyses revealed that mRNA levels of PTH, CaSR, and VDR were well preserved, and several growth factors (e.g. TGF-beta1-induced protein) were abundantly expressed in II°-HPT. Using organ cultures of hyperparathyroid tissues, in which PTH release and CaSR are well preserved for a prolonged period, we have demonstrated that phosphate stimulates parathyroid cell proliferation not only in II°-HPT but also in I°-HPT. Although the mechanism responsible for phosphate-induced cell proliferation remains to be elucidated, our in vitro findings suggest that both parathyroid tissues preserve to some extent a physiological response system to hyperphosphatemia as observed in normal parathyroid cells.
Patterns of Chromosomal Imbalances in Parathyroid Carcinomas
In this study we have characterized chromosomal imbalances in a panel of 29 parathyroid carcinomas using comparative genomic hybridization (CGH). The most frequently detected imbalances were losses of 1p and 13q that were seen in >40% of the cases. The commonly occurring regions of loss were assigned to 1p21-p22 (41%), 13q14-q31 (41%), 9p21-pter (28%), 6q22-q24 (24%), and 4q24 (21%), whereas gains preferentially involved 19p (45%), Xc-q13 (28%), 9q33-qter (24%), 1q31-q32 (21%) and 16p (21%). The distribution of CGH alterations supports the idea of a progression of genetic events in the development of parathyroid carcinoma, where gains of Xq and 1q would represent relatively early events that are followed by loss of 13q, 9p, and 1p, and by gain of 19p. A sex-dependent distribution was also evident for two of the common alterations with preferential gain of 1q in female cases and of Xq in male cases. When the CGH profiles for the 29 carcinomas were compared with our previously published results for sporadic parathyroid adenomas, highly significant differences were revealed. Loss of 1p, 4q, and 13q as well as gains of 1q, 9q, 16p, 19p and Xq were significantly more common in the carcinomas than in the adenomas. In contrast, loss of the 11q13 region, which is the most common CGH abnormality in sporadic adenomas, was not detected in any of the carcinomas. Taken together, the findings identify several candidate locations for tumor suppressor genes and oncogenes that are potentially involved in parathyroid carcinogenesis.
Tissue-Engineered Thyroid Cell Sheet Rescued Hypothyroidism in Rat Models After Receiving Total Thyroidectomy Comparing with Nontransplantation Models
For hormonal deficiency caused by endocrine organ diseases, continuous oral hormone administration is indispensable to supplement the shortage of hormones. In this study, as a more effective therapy, we have tried to reconstruct the three-dimensional thyroid tissue by the cell sheet technology, a novel tissue engineering approach. The cell suspension obtained from rat thyroid gland was cultured on temperature-responsive culture dishes, from which confluent cells detach as a cell sheet simply by reducing temperature without any enzymatic treatment. The 8-week-old Lewis rats were exposed to total thyroidectomy as hypothyroidism models and received thyroid cell sheet transplantation 1 week after total thyroidectomy. Serum levels of free triiodothyronine (fT 3 ) and free thyroxine (fT 4 ) significantly decreased 1 week after total thyroidectomy. On the other hand, transplantation of the thyroid cell sheets was able to restore the thyroid function 1 week after the cell sheet transplantation, and improvement was maintained for 4 weeks. Moreover, morphological analyses showed typical thyroid follicle organization, and anti-thyroid-transcription-factor-1 antibody staining demonstrated the presence of follicle epithelial cells. The presence of functional microvessels was also detected within the engineered thyroid tissues. In conclusion, our results indicate that thyroid cell sheets transplanted in a model of total thyroidectomy can reorganize histologically to resemble a typical thyroid gland and restore thyroid function in vivo . In this study, we are the first to confirm that engineered thyroid tissue can repair hypothyroidism models in rats and, therefore, cell sheet transplantation of endocrine organs may be suitable for the therapy of hormonal deficiency.
Management of Hyperthyroidism Due to Graves' and Nodular Diseases
Endocrine surgeons have had an important role in the management of hyperthyroidism due to either Graves' disease or toxic nodule(s). Since alternative treatments such as antithyroid drugs or radioiodine are also available, the decision‐making for management should be based on clear assessment of advantages and limitations of each of the treatment options. Surgery provides rapid resolution of these conditions, and cure rates are high, although it may be associated with perioperative complications and postoperative thyroid dysfunction. The authors' experience in the surgical treatment of hyperthyroidism and a review of the recent literature are outlined in this report.