Plasma free metanephrines in the diagnosis of pheochromocytoma: diagnostic accuracy and strategies for Japanese patients.

Measuring the levels of the plasma free metanephrines (PFMs) represents a recently developed and promising test for the diagnosis of pheochromocytoma in the United States and Europe. As this test has not yet been evaluated in Japan, it is necessary to evaluate the diagnostic efficacy of measuring the levels of PFMs compared with the standard measurement of the urinary excretion of metanephrines (uMNs) whose reliability is well established to detect of pheochromocytoma. A total of 101 Japanese subjects clinically suspected of having pheochromocytoma in were included in this study.

Thyroglobulin may affect telomerase activity in thyroid follicular cells.

Telomerase (TA) activity is known to be present in malignant tumor cells, but not in most somatic differentiated cells. TA shows relatively high activity in thyroid cancer cells, but reports vary. This fact prompted us to elucidate whether cell component inhibitors of TA in the thyroid follicles can modulate its activity.

Hypovitaminosis D in type 2 diabetes mellitus: Association with microvascular complications and type of treatment.

The prevalence of hypovitaminosis D has been recently reevaluated, and diabetes is considered as a risk factor for osteoporosis. We studied the association of the prevalence of hypovitaminosis D with the clinical features of diabetes. We conducted the observational study in 581 Japanese patients with type 2 diabetes mellitus and 51 normal subjects, and analyzed the relationship between serum 25-hydroxyvitamin D (25-OHD) concentration and the clinical features associated with type 2 diabetes.

The relationship between glycemic control and plasma vascular endothelial growth factor and endothelin-1 concentration in diabetic patients.

Understanding the causes of diabetic vascular complications has become an increasingly important issue because of the rapidly rising prevalence of diabetes. Recently discovered vasoconstrictors and angiogenesis regulators, such as endothelin (ET) and vascular endothelial growth factor (VEGF), have been intensely studied for possible pathogenic roles in diabetic vascular complications. The present study was undertaken to clarify the effect of glycemic control on serum VEGF and plasma ET-1 concentrations in diabetic patients, and to identify other factors that may cause fluctuations of these substances.

cGMP inhibits GTP cyclohydrolase I activity and biosynthesis of tetrahydrobiopterin in human umbilical vein endothelial cells.

Tetrahydrobiopterin (BH4) acts as an essential cofactor for the enzymatic activity of nitric oxide (NO) synthases. Biosynthesis of the cofactor BH4 starts from GTP and requires 3 enzymatic steps, which include GTP cyclohydrolase I (GCH I) catalysis of the first and rate-limiting step. In this study we examined the effects of cGMP on GCH I activity in human umbilical vein endothelial cells under inflammatory conditions.

Urinary sorbitol measurement and the effect of an aldose reductase inhibitor on its concentration in the diabetic state.

The amounts of sorbitol (SOR) excreted in 24-h urine were determined on two groups, i.e., diabetic and nondiabetic patients, using an improved method in which ion exchange resin column processing was applied, and these levels were compared with SOR levels in whole blood.

Distinctive response of thyroid-infiltrating mononuclear cells to B cell activation through CD40 and interleukin-4 in Graves' patients.

The possible role of abnormal T cell-dependent B-cell activation in Graves' disease was investigated by comparing lymphocyte subset distribution and the production of soluble CD8 (sCD8), sCD23, IL-10 and IL-12 by peripheral blood cells (PBMC) and thyroid-infiltrating lymphocytes (TL) in vitro. In TL, the percentage of CD8(+) cells was slightly higher and the sCD8 concentration was significantly higher than in PBMC. The ratio CD23(+) cells to CD20(+) cells (activated B/pan B cells) was increased in TL compared to PBMC from Graves' or normal controls, although the percentage of CD20(+) cells was decreased.

Lung cancer associated with hypercalcemia induced by concurrently elevated parathyroid hormone and parathyroid hormone-related protein levels.

In general, many cases of malignancy-associated hypercalcemia are due to HHM. In patients with humoral hypercalcemia of malignancy (HHM), it has been reported that plasma parathyroid hormone-related protein (PTHrP) and cyclic adenosine monophosphate (cAMP) levels were elevated, while plasma PTH and active vitamin D(3) levels were suppressed. Our patient showed hypercalcemia with a concurrent increase in plasma and tumor tissue PTHrP and PTH concentrations and also high cAMP and low 1-25(OH)(2)VD(3) levels in the plasma.

cAMP inhibits cytokine-induced biosynthesis of tetrahydrobiopterin in human umbilical vein endothelial cells.

We studied the effects of cAMP on cytokine (interferon-gamma plus tumor necrosis factor-alpha)-induced stimulation of tetrahydrobiopterin (BH4) synthesis in human umbilical vein endothelial cells (HUVEC). The cytokine mixture caused a marked increase in the biosynthesis and release of BH4 by HUVEC. Dibutyryl-cAMP produced a dose-dependent inhibition of this cytokine-induced stimulation of synthesis and release of BH4 by these cells.