Yoshimasa Shishiba

Retrospective analysis of long-term surgical results in acromegaly: preoperative and postoperative factors predicting outcome

OBJECTIVE Sixty‐one of 83 patients with acromegaly treated between 1969 and 1993 were analysed retrospectively to clarify which early postoperative factors were significant predictors of a successful long‐term outcome and which preoperative factors significantly influenced the early postoperative results.

Elevated immunoreactive insulin concentration during spontaneous attacks in thyrotoxic periodic paralysis

Abstract It has been well documented that administration of insulin or procedures that increase endogenous insulin secretion may provoke the attack of hypokalemic periodic paralysis. However, there have been no reports on the endogenous insulin levels before and during spontaneous attack of periodic paralysis. In the present investigation we measured concentration of blood glucose, serum immunoreactive insulin (IRI), human growth hormone (HGH), Na, and K during spontaneous attacks of periodic paralysis and also after an oral load of 100 g glucose in seven thyrotoxic patients with the history of periodic paralysis. Three attacks of paralysis were observed in two patients. In one patient basal level of IRI was abnormally high, and the postglucose IRI response was exaggerated. Preceding the attack, IRI increased to 500 μU/ml from the basal level of 75 μU/ml. In the other patient it increased to 105 μU/ml from the basal level of 7 μU/ml at the onset of paralysis. Those levels observed at the onset of paralysis were abnormally high when compared to those in patients in whom no attacks were observed. HGH, blood glucose, and Na had no correlation with paralysis, although K decreased during the attack. Thus, we demonstrated for the first time that the spontaneous attack of paralysis was preceded by an increased secretion of insulin. These results suggested the following two abnormalities in thyrotoxic periodic paralysis: abnormal increase in insulin in response to glucose or dietary load, and decrease in muscle membrane potential in response to elevated insulin.

Studies on electrolyte metabolism in idiopathic and thyrotoxic periodic paralysis

Abstract A study of arteriovenous serum potassium and sodium changes during an induced attack of periodic paralysis was undertaken in 7 patients with idiopathic periodic paralysis and 6 patients with thyrotoxic periodic paralysis. In both types of periodic paralysis, a constant positive arteriovenous difference of potassium was obtained during the development of paralysis. The findings lend further support to the hypothesis that the cellular migration of potassium from the extracellular space is the mechanism of hypokalemia in both idiopathic and thyrotoxic periodic paralysis.

Pit‐1 gene expression in human pituitary adenomas using the reverse transcription polymerase chain reaction method

OBJECTIVE Previous studies of Pit‐1 expression in human pituitary tumours have produced conflicting results. We have studied expression of Pit‐1 mRNA in human pituitary adenomas, as well as in normal human and rat pituitaries, and results were compared with clinical, histological, and immunohistochemical features. In addition, expression of GH, PRL, and TSH‐β mRNA was also studied and compared with Pit‐1 gene expression.

Studies on electrolyte metabolism in idiopathic and thyrotoxic periodic paralysis: III. Intra- and extracellular concentrations of potassium and sodium in muscle and their changes during induced attacks of paralysis☆

Abstract Muscle biopsy studies were performed in 8 patients with idiopathic hypokalemic periodic paralysis, 8 patients with thyrotoxic hypokalemic periodic paralysis and 7 patients with thyrotoxicosis without periodic paralysis. Content and intracellular concentration of potassium are signicantly reduced in idiopathic periodic paralysis as compared to thyrotoxic periodic paralysis. There is no constant and characteristic change in intracellular concentration of potassium per se during paralysis, while K i K o ratio increases roughly parallel to the severity of induced paralysis.

Effect of Thyroid Hormone Deficiency on Proteoglycan Synthesis by Human Skin Fibroblast Cultures

Proteoglycans and hyaluronic acid synthesized by human skin fibroblasts in culture were characterized, and the effect of thyroid hormone deficiency was examined. The fibroblasts in culture synthesize hyaluronic acid, dermatan sulfate (DS) proteoglycans and heparan sulfate (HS) proteoglycans. Hyaluronic acid is almost exclusively secreted into the medium. Among the proteoglycans synthesized during 24 h label, about 70% were secreted into the medium and the remaining 30% were associated with the cell layer. About 70% of proteoglycans secreted into the medium contained DS and the remaining 30% contained HS. For cell-associated proteoglycans, 60% contained HS and the remainder contained DS. The size distributions of the glycosaminoglycans from both DS and HS proteoglycans were similar, with an average Mr of approximately 30,000. Incubation of fibroblasts in thyroid hormone deficient medium increased net synthesis of hyaluronic acid (approximately 50%) and all species of proteoglycans (approximately 85%). 3H/35S ratios in the chondroitin 4-sulfate disaccharide isolated with HPLC were not altered in thyroid hormone deficient cultures, indicating that the specific activity of 3H in UDP-N-acetylhexosamine precursors did not change. The increased incorporation of 3H into hyaluronic acid and of 3H and 35S into DS and HS proteoglycans thus indicates increased net synthesis. Degradation of cell-associated proteoglycans was not influenced by thyroid hormone deficiency.

Shift from CRH to ACTH Production in a Thymic Carcinoid with Cushing’s Syndrome

We report a case of a 25-year-old man with Cushings syndrome due to an ACTH and CRH-producing thymic carcinoid. Immunohistology and radioimmunoassay demonstrated CRH and a lesser amount of ACTH in the resected primary tumor. After a symptom-free period, the tumor recurred and the patient died. Tumor obtained at autopsy contained mainly ACTH and lesser quantities of CRH. We conclude that this thymic carcinoid initially produced mainly CRH and then transformed to secrete mainly ACTH, suggesting that endocrine tumors may change their functional phenotype.

Studies on electrolytes metabolism in idiopathic and thyrotoxic periodic paralysis: II. Total exchangeable sodium and potassium

Abstract A study of total exchangeable potassium, sodium and total body water was undertaken in 8 normal subjects, 7 patients with thyrotoxicosis without periodic paralysis, 8 patients with idiopathic periodic paralysis and 7 patients with thyrotoxic periodic paralysis. Our findings show that total exchangeable potassium is modestly but significantly reduced in idiopathic periodic paralysis, but within normal limits in thyrotoxic periodic paralysis.

Serum alpha-subunit levels in patients with pituitary adenomas.

OBJECTIVE We investigated preoperative and postoperative serum α‐subunit levels and the α‐subunit response to TRH in patients with various types of pituitary tumour and correlated the data with histological findings in order to clarify the significance of α‐subunit measurement in pituitary adenomas.

Immunohistochemical Heterogeneity Within Clinically Nonfunctioning Pituitary Adenomas.

To investigate whether adenohypophysial hormone expression is heterogeneous within individual clinically nonfunctioning pituitary adenomas, immunohistochemical examinations were performed on tissues obtained by multiple sampling of 11 adenomas. Stained sections were assessed by morphometric image analysis as well as semiquantitative estimation under microscopy. All tumors except one were immunopositive for one or more gonadotropins. Results were divided into five grades based on the proportion of immunoreactive cells per section. Semiquantitative estimation showed only a one-grade difference among samples from the same tumor in four cases for FSHβ and in two cases for LHβ. These qualitative similarities between multiple samples were confirmed by morphometric image analysis.From the practical standpoint of making a diagnosis of nonfunctioning pituitary adenoma, it is not necessary to take into account immunohistochemical heterogeneity within an individual tumor, and immunohistochemical findings in a given sample obtained at surgery can be regarded as representative of the entire adenoma.