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Biomedical subjects

H Koshiyama

Publications and source records attributed to H Koshiyama.

At least 19 recordsLinked to original sources
PubMed2000

Thyrotropin regulation of cyclic adenosine monophosphate production in human coronary artery smooth muscle cells.

Thyroid disease has been associated with the occurrence of pathophysiologic changes in the vasculature that may result in part from altered serum thyroid hormone and serum lipid levels. Thyrotropin (TSH) levels are also altered in thyroid disease, but a direct effect of TSH on vascular smooth muscle has not previously been considered. In the present study, human coronary artery smooth muscle cells (CASMC) were induced into two morphologically distinct forms by culturing in either (1) growth factor supplemented, 0.5% serum medium (SmGM-3) or (2) basal medium (SmBM) plus 10% fetal bovine serum (FBS). Intracellular cyclic adenosine monophosphate (cAMP) accumulation was determined by radioimmunoassay after exposure to increasing doses of bovine TSH. Cells grown in SmBM/10% FBS for 3 days exhibited a dose-dependent increase in intracellular cAMP that reached a level 10 times higher than baseline at the highest dose examined (100 mIU/mL). In contrast, cells grown in SmGM-3 medium exhibited no change in intracellular cAMP on exposure to increasing TSII. Low serum (0.5% FBS) reduced the ability of TSH to stimulate cAMP above the control value in CASMC. Pretreatment of CASMC with either transforming growth factor-beta1 (TGF-beta1) or tumor necrosis factor-alpha (TNF-alpha) lowered basal levels of cAMP production, but did not inhibit the ability of TSH to stimulate cAMP production. Human, but not rat aortic smooth muscle cells in culture also responded to TSH with a significant increase in cAMP. The results of this study suggest that TSH may exert direct effects on vascular smooth muscle mediated by adenylate cyclase activation that could conceivably affect the progression of vascular disease associated with thyroid dysfunction.

Actins↗
PubMed2000

Decrease in carotid intima-media thickness after 1-year therapy with etidronate for osteopenia associated with type 2 diabetes.

It has been suggested that bisphosphonates may have some antiatherogenic actions in experimental animals or in vitro, but their effects on the atherogenic process in humans has not been reported. In the present study the effect of etidronate treatment on carotid arterial intima-media thickness was prospectively examined in 57 subjects with type 2 diabetes associated with osteopenia. After 1 yr of therapy with cyclical etidronate (200 mg/day for 2 weeks every 3 months), intima-media thickness showed a decrease (mean +/- SE, 0.038 +/- 0.011 mm), which was significantly different from a change in 57 control subjects (0.023 +/- 0.015 mm; P < 0.005). Cardiovascular parameters were not changed after etidronate treatment. These findings suggest that etidronate in clinical dosage may have an antiatherogenic action, at least in type 2 diabetes, although its mechanisms remain to be elucidated.

Bone Diseases, Metabolic↗
PubMed1999

Lymphocytic hypophysitis presenting with diabetes insipidus: MR findings.

It has been thought that neurohypophysial involvement manifesting as central diabetes insipidus in lymphocytic hypophysitis is rare. The radiological and clinicopathological features of two cases represent a variant of lymphocytic adenohypophysitis and/or lymphocytic infundibulo-neurohypophysitis are discussed.

Diabetes Insipidus↗
PubMed1999

Medial plantar nerve conduction velocities among patients with vibration syndrome due to chain-saw work.

OBJECTIVE: The present study examined the effect of the vibration syndrome (VS) on the peripheral nervous system in the lower extremities. METHODS: Thirty-eight patients with VS due to previous exposure to vibration from chain-saw work and 55 age-matched controls were examined for sensory nerve conduction velocities in the medial plantar nerve (SCV-P). The patient group was divided into two subgroups, one with (n=19) and the other without vibration-induced white finger (VWF; n=19). RESULTS: Analysis of variance of SCV-P for the three groups showed significant difference (F(2,89)=10.65, P < 0.0001). A significant difference was found between the controls and the VWF(+) group (P < 0.0001) but not between the controls and the VWF(-) group (P=0.0508) by multiple comparison using Scheffe's method. CONCLUSION: These findings suggest that VS affects the peripheral nervous system function in the lower extremities via mediation of circulatory disturbance manifested as VWF.

Action Potentials↗
PubMed1999

Effect of calcium channel blocker amlodipine on the intimal-medial thickness of carotid arterial wall in type 2 diabetes.

Although several reports have suggested that calcium channel blockers may inhibit progression of atherosclerosis in animals, it is still controversial whether they have any clinically significant antiatherogenic action in humans. The measurement of intimal-medial thickness (IMT) of the common carotid artery by B-mode ultrasound technique has been recognized as a powerful and noninvasive method to evaluate early atherosclerotic lesions. We investigated the effect of treatment with amlodipine, a powerful calcium channel blocker, on IMT. Twenty-two hypertensive patients with type 2 diabetes were enrolled in a prospective open study. An amlodipine group (amlodipine, 5 mg; n = 11) and a control group receiving angiotensin-converting enzyme inhibitors (n = 11) were studied before and 6 months after treatment. Amlodipine treatment caused a significant decrease in IMT compared with control (-0.052 +/- 0.017 vs. 0.011 +/- 0.021 mm; p < 0.05). Although the exact mechanisms remain to be elucidated, our preliminary result suggests that amlodipine has an antiatherogenic action in type 2 diabetes.

Aged↗
PubMed1999

A case of ectopic thyroid in lateral neck associated with Graves' disease.

Thyroid follicles in the lateral position of the neck are usually thought to represent the metastasis of thyroid carcinoma. Here we present a case of a 28-year-old woman with accessory ectopic thyroid associated with Graves' disease. Despite a history of Graves' disease poorly controlled with large dose propylthiouracil she was found to be pregnant and artificial abortion was planned. Thyroid scintigraphy was carried out, which indicated an uptake into the region above the left lobe as well as into both lobes of the thyroid gland. In order to control hyperthyroidism and to exclude the possibility of metastasis, total thyroidectomy with tumor resection was performed before the artificial abortion. Pathological examinations of the thyroid gland indicated findings compatible with Graves' disease. The lateral neck mass was revealed to be composed of nonneoplastic thyroid tissue, showing similar histological findings to those of the goiter, which were consistent with Graves' disease. Taken together with several previous reports, it appears that there are some cases with lateral ectopic thyroid tissue, whose pathogenetic mechanism remains to be elucidated.

Abortion, Induced↗
PubMed1999

An adult-onset case of argininosuccinate synthetase deficiency presenting with atypical citrullinemia.

A 52-year-old heavy drinker presented with repeated episodes of disturbance of consciousness and an increase in serum ammonia level, triggered by excessive alcohol intake. He was diagnosed as having adult-onset citrullinemia with deficiency of hepatic argininosuccinate synthetase (ASS) activity. Cranial magnetic resonance imaging (MRI) showed high-intensity lesions in the central pons and the bilateral middle cerebellar peduncles on T2-weighted images. Although almost all cases of adult-onset citrullinemia have been reported to be enzymologically classified as type II, the serum amino acid pattern and serum level of human pancreatic secretory trypsin inhibitor (hPSTI) were atypical for type II in the present case.

Adult↗
PubMed1998

The gene responsible for pseudohypoparathyroidism type Ib is paternally imprinted and maps in four unrelated kindreds to chromosome 20q13.3.

Hypocalcemia and hyperphosphatemia caused by parathyroid hormone (PTH)-resistance are the only discernible abnormalities in pseudohypoparathyroidism type Ib (PHP-Ib). Because mutations in the PTH/PTH-related peptide receptor, a plausible candidate gene, had been excluded previously, we conducted a genome-wide search with four PHP-Ib kindreds and established linkage to a small telomeric region on chromosome 20q, which contains the stimulatory G protein gene. We, furthermore, showed that the genetic defect is imprinted paternally and thus is inherited in the same mode as the PTH-resistant hypocalcemia in kindreds with PHP-Ia and/or pseudo-pseudohypoparathyroidism, two related disorders caused by different stimulatory G protein mutations.

Chromosome Mapping↗
PubMed1998

Clonal analysis helps to differentiate aberrant thyroid tissue from thyroid carcinoma.

A rare case of multiple aberrant of thyroid tissues in the tongue and lymph nodes of the bilateral neck was studied by immunohistochemistry and molecular clonal analysis to determine whether these tissues represent aberrant ectopic thyroid or metastases of a thyroid carcinoma. The thyroid tissues in the tongue and lymph nodes were all of polyclonal origins, consistent with ectopic thyroid in the tongue and bilateral cervical lymph nodes, rather than malignant thyroid tissues. This case shows that molecular clonal analysis can be used to distinguish aberrant thyroid from metastases of thyroid carcinoma.

Adult↗
PubMed1998

Potent inhibitory effect of troglitazone on carotid arterial wall thickness in type 2 diabetes.

There is increasing evidence that insulin resistance may be causally related to atherosclerosis. The measurement of common carotid arterial intimal and medial complex thickness (IMT) by B-mode ultrasound technique has been recognized as a powerful and non-invasive method to evaluate early atherosclerotic lesions. We investigated the effect of treatment with troglitazone, an insulin sensitizer, on IMT in a total of 135 Japanese subjects with type 2 diabetes. Troglitazone (400 mg daily) was administered for 6 months in 57 patients. Compared to control group (n = 78), the group given troglitazone showed a significant decrease in IMT as early as 3 months after the administration (IMT change: -0.080[SE 0.016] mm vs. control 0.027[SE 0.007] mm, P < 0.001). The decrease in IMT was also found after 6 months, although further decrease was not observed. Both HbA1c and postprandial serum triglycerides were decreased after troglitazone, but there was no statistically significant relation between a decrease in IMT and those in HbA1c or postprandial triglycerides. These findings indicate that troglitazone has a potent inhibitory effect on progression of early atherosclerotic lesions probably through the decreased insulin resistance in type 2 diabetes.

Carotid Arteries↗