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Biomedical subjects

H Ibayashi

Publications and source records attributed to H Ibayashi.

At least 19 recordsLinked to original sources
PubMed1996

Portal-systemic shunting in a patient with normal portal vain pressures and histological evidence of idiopathic portal hypertension.

Although idiopathic portal hypertension (IPH) is clinically characterized by portal hypertension and marked splenomegaly, we have experienced a case of spontaneous portal-systemic shunt without splenomegaly in whom the liver histology resembled IPH but with normal portal pressure. We admitted a 64 year old man who had suffered from hepatic encephalopathy for 2 years. Laparoscopy revealed a dark grey liver with a sharp edge and a concave surface. Examination of a liver biopsy specimen revealed peri-portal fibrosis consistent with IPH. A single, large, portal-systemic shunt was identified by percutaneous transhepatic portography. The shunt arose from the left gastric vein and flowed through the left renal vein into the inferior vena cava. No varices were identified. There were no morphological changes in the hepatic or portal veins. Portal vain pressure was normal. There was a slight difference between the portal pressure and the wedged hepatic vein pressure, suggesting a presinusoidal block. This case raises important questions concerning the aetiology of IPH and the relationship between portal hypertension and the development of collateral venous circulation.

Collateral Circulation↗
PubMed1994

Complete atrioventricular block during left heart catheterization.

A 75-year-old male underwent cardiac catheterization for frequent ventricular premature contractions and reduced left ventricular function. ECG on admission showed complete right bundle branch block (RBBB) and left anterior hemiblock. Right heart catheterization was performed uneventfully, but complete atrioventricular block (CAVB) occurred suddenly when a pig-tail catheter was inserted into the left ventricle. Electrophysiological study identified this CAVB as HV block, and demonstrated HV prolongation in sinus rhythm. The coronary angiogram revealed no obstructive lesion or spasm with ergonovine. The reproducibility of the CAVB was demonstrated. The final CAVB developed and persisted for more than one week, requiring the implantation of a permanent pacemaker (DDD). Complete atrioventricular block induced during left heart catheterization is very rare. Pre-existing RBBB with left anterior or posterior hemiblock and reduced left ventricular function may be common factors in patients with this condition. Emergency pacing equipment should always be on-line when left heart catheterization is conducted in such patients.

Aged↗
PubMed1994

[A case of adrenal pheochromocytoma with normotention and normal levels of urinary excretion of catecholamines].

A 62-year-old man was admitted to our hospital for further examination of right adrenal mass accidentally pointed out by ultrasonogram. He had no symptoms and no physiological abnormalities. Endcrinological examinations revealed normal adrenocortical function, excluding the possibility of functioning adrenocortical adenoma. Pheochromocytoma seemed to be also unlikely since 24-hr urinary excretion of catecholamines were within normal limits. The tumor was surgically removed and histopathologically diagnosed as pheochromocytoma. This case of adrenal incidentaloma is unique in that little sign of pheochromocytoma was presented before operation. The reasons were discussed especially in respect of tissue contents of catecholamines and opioid peptide in comparison with other cases with pheochromocytoma we had experienced.

Adrenal Gland Neoplasms↗
PubMed1993

Acromegaly with hyperprolactinemia developed after bilateral adrenalectomy in a patient with Cushing's syndrome due to adrenocortical nodular hyperplasia.

A 27-yr-old woman was referred for evaluation of acromegaly and hyperprolactinemia. She had undergone left adrenalectomy at 12 and right adrenalectomy at 17 for Cushing's syndrome due to adrenocortical nodular hyperplasia. At this time a pituitary tumor was found by brain computerized tomography, but plasma levels of growth hormone (GH), prolactin (PRL) and adrenocorticotropin (ACTH) were normal. When she was 23, symptoms and signs of acromegaly and subsequently galactorrhea-amenorrhea had developed. Plasma GH and PRL were increased and she was followed up by the administration of bromocriptine (2.5 mg-12.5 mg/day, p.o.). However the plasma GH level had been increasing gradually. On admission, plasma GH and PRL were high (19.5 micrograms/L, 61.0 micrograms/L, respectively) and increased in response to thyrotropin releasing hormone (TRH, 500 micrograms i.v.). An intrasella mass, which had been detected when she was 17, had become enlarged and was removed by Hardy's operation. Microscopically, the resected tumor was an eosinophilic adenoma. Immunohistochemical studies showed GH, PRL and ACTH positive cells localized in the tumor. Immunoultrastructural analysis of the tumor confirmed that GH, PRL and ACTH were present in secretory granules and Golgi apparatus in the tumor cells. The patient was a rare case of acromegaly with hyperprolactinemia developed after bilateral adrenalectomy of Cushing's syndrome due to adrenocortical nodular hyperplasia, all of which manifestations may be caused by a GH, PRL and ACTH secreting pituitary adenoma.

Acromegaly↗
PubMed1992

[Long-term treatment of acromegaly and gigantism with octreotide (SMS 201-995)].

Twenty-one patients with active acromegaly and two patients with pituitary gigantism were treated with the long-acting somatostatin analogue octreotide (100-600 micrograms/day, sc, two or three times daily or 300-1500 micrograms daily by intermittent sc infusion) for 9-63 months. There was rapid clinical improvement. The fasting plasma GH levels were significantly suppressed (less than 50% of the values before treatment) in 17 patients and were normalized (less than 5 ng/ml) in 6 patients (27.3%). Plasma IGF-I levels were lowered by 50% and were normalized in 7 out of 18 cases. The effect of octreotide on pituitary tumor size was evaluated in 13 patients. In 4 cases, the shrinkage of the pituitary tumor was detected by computed tomographic scans and/or magnetic resonance imaging studies. The drug was generally well tolerated. However, there were probably newly formed gallstones in two patients during the therapy. Our study suggests that octreotide is an effective and relatively safe new approach for treating active acromegaly and gigantism.

Acromegaly↗
PubMed1992

Fatal abdominal thorotrast granuloma.

We report a case of fatal abdominal thorotrast granuloma seen in a 65-year-old man who had undergone a femoral angiography of thorotrast with some accidental extravasation 49 years previously. As the thorotrast granuloma gradually increased in size, it caused ureteral obstruction, venous thrombosis, and perforation of the urinary bladder and rectum. Symptomatic abdominal thorotrast granuloma is quite rare and this is the first reported case of the granuloma associated with perforation through the urinary bladder and rectum.

Abdominal Neoplasms↗
PubMed1990

Corticotropin-releasing hormone- and adrenocorticotropin-producing pituitary carcinoma with metastases to the liver and lung in a patient with Cushing's disease.

A 53-yr-old man with Cushing's disease was found to have a pituitary carcinoma with metastases to the liver and lung which produced both CRH and ACTH simultaneously. Despite removal of the pituitary tumor, his Cushing's disease worsened. Endocrinological examination then demonstrated elevated plasma CRH and markedly elevated plasma ACTH, beta-lipotropin, and cortisol concentrations, increased urinary 17-hydroxycorticosteroid and 17-ketosteroid excretion, and no suppression of serum cortisol after low or high dose dexamethasone administration. Urinary 17-hydroxycorticosteroid excretion increased in response to metyrapone, and lysine vasopressin elicited a striking increase in plasma ACTH. A computed tomographic scan of abdomen revealed multiple hypodense areas in the liver and bilateral adrenal hyperplasia. Postmortem histological examination revealed a necrotic hemorrhagic pituitary carcinoma with metastases to the liver, lung, and olfactory bulb. Immunohistochemical staining, gel filtration, and Northern blot analysis of liver and lung metastases revealed evidence of the production of both CRH and ACTH in these metastases. We concluded that the patient's pituitary carcinoma produced both CRH and ACTH.

Adrenocorticotropic Hormone↗
PubMed1990

Decreased VIP content in peripheral nerve from streptozocin-induced diabetic rats.

After induction of diabetes with streptozocin (STZ-D) in rats, we measured vasoactive intestinal polypeptide (VIP) content in sciatic nerve and spinal cord obtained from nondiabetic, untreated STZ-D, and insulin-treated STZ-D rats. Eight weeks after the onset of diabetes, caudal nerve conduction velocity (NCV) in the untreated STZ-D rats (n = 13) was slower than in the controls (n = 11; mean +/- SE 30.9 +/- 0.6 vs. 41.4 +/- 1.8 m/s, P less than 0.001). The decrease in NCV was less marked in the insulin-treated STZ-D rats (n = 11; 36.3 +/- 0.9 m/s, P less than 0.05 vs. control). VIP content in sciatic nerve decreased in the untreated STZ-D rats (1.33 +/- 0.23 ng/g wet wt) compared with the other groups (control, 3.10 +/- 0.44, P less than 0.01; insulin-treated STZ-D, 2.44 +/- 0.55, P less than 0.05). However, in spinal cord, VIP content was not significantly different among the three groups. The VIP levels in sciatic nerve showed a positive correlation with NCV (r = 0.430, P less than 0.01). In addition, an inverse correlation between VIP levels and blood glucose levels was observed (r = -0.5624, P less than 0.001). NCV was also inversely correlated with blood glucose levels (r = -0.7662, P less than 0.001). Together with a previous morphological study, these findings suggest a possible causal relationship between reduced VIP content and diabetic neuropathy.

Animals↗
PubMed1989

[A multicenter clinical trial of SMS 201-995 (octreotide acetate) in acromegaly and gigantism].

Sixty-four patients with active acromegaly and three patients with gigantism were treated with the long acting somatostatin analog SMS 201-995 (50-500 micrograms, sc, every 6-12 h or 150-880 micrograms daily by intermittent sc infusion, for up to 114 weeks). The fasting plasma GH levels were significantly suppressed (less than 50% of the values before treatment) in 49 patients and became normal in 18 patients. Suppression of GH secretion was associated with normalization of plasma somatomedin-C levels (14 out of 30 cases) and significant clinical improvement such as disappearance of headache and decrease of excessive sweating. Shrinkage of pituitary tumors as determined by computed tomography and/or magnetic resonance imaging studies occurred in 11 out of 40 cases. Side effects were minimal and tolerable. SMS 201-995 appears to be an effective agent for the treatment of acromegaly and gigantism.

Acromegaly↗
PubMed1989

Decrease in insulin binding to aortic endothelial cells cultured with high glucose concentration.

We studied the effects of glucose on specific insulin binding to cultured endothelial cells from the bovine aorta. We cultured the cells in Dulbecco's modified Eagle's medium, containing 100 or 300 mg/dl glucose or 100 mg/dl glucose plus 200 mg/dl mannitol. We added 125I-insulin to monolayers of these cells and counted the radioactivity resulting. Specific insulin binding increased with time and dosage. Maximal binding resulted from 0.17 nM 125I-insulin being incubated for 30 min at 37 degrees C, and amounted to 0.35% per 10(5) cells being bound in cultures of 100 mg/dl glucose. The higher concentration of glucose led to significantly less binding (P less than 0.05) (0.24 +/- 0.03% vs. 0.38 +/- 0.02%, n = 6). The addition of mannitol, on the other hand, did not affect binding. All three incubation conditions produced curvilinear competition curves. Scatchard analysis showed that insulin bound significantly less (P less than 0.05) to endothelial cells in 300 mg/dl glucose than to those in 100 mg/dl glucose (4.0 +/- 1.2 nmol/l vs. 12.8 +/- 3.1, n = 6, mean +/- SEM). Insulin binding capacity, however, did not change. We conclude that glucose can reduce insulin binding to endothelial cells and that it may reduce receptor-related insulin transport into and out of the cells.

Animals↗
PubMed1989

Alpha-human atrial natriuretic polypeptide inhibits 19-hydroxy-androstenedione secretion by human adrenal cells.

We investigated the effect of ACTH, angiotensin II (AII), and alpha-human atrial natriuretic polypeptide (alpha-hANP) which plays an important role of water-electrolytes balance, on 19-hydroxyandrostenedione (19-hydroxyandrost-4-ene-3,17-dione, 19-OH-A-dione) secretion by cultured human adrenal cells. 19-OH-A-dione in culture media was measured using a specific RIA. Basal 19-OH-A-dione secretion by adrenal cells was 0.69 +/- 0.08 ng/3h/10(6) cells and significantly rose to 1.17 +/- 0.14 ng/3h/10(6) cells in the presence of ACTH, but not in the presence of A II. These results demonstrate that 196-OH-A-dione is directly secreted from adrenal cells. alpha-hANP significantly inhibited both basal and ACTH-stimulated 19-OH-A-dione secretions, as well as aldosterone. These results demonstrate that alpha-hANP inhibits aldosterone activity by means of the inhibition of both aldosterone and 19-OH-A-dione (an aldosterone amplifier) secretion by adrenal cells.

Adrenal Glands↗
PubMed1989

Cardiovascular, renal and endocrine effects of alpha-human atrial natriuretic peptide in patients with Cushing's syndrome and primary aldosteronism.

The pharmacological effects of synthetic alpha-human atrial natriuretic peptide (alpha-hANP) in patients with Cushing's syndrome and primary aldosteronism were compared with those in normal volunteers. An infusion of synthetic alpha-hANP at 0.1 microgram/kg per min for 20 min produced a maximal plasma hANP level of 800-1200 pg/ml in patients with Cushing's syndrome and primary aldosteronism, and in normal subjects. There were significant decreases in the mean blood pressure (-10 to -15 mmHg) in patients with Cushing's syndrome and primary aldosteronism, similar to those in normal subjects. The plasma cyclic 3'5'-guanosine monophosphate (cGMP) concentrations of both groups of patients were increased fivefold over the baseline level following the infusion. Infusion of synthetic alpha-hANP caused a greater increase in the rate of sodium excretion in patients with Cushing's syndrome and primary aldosteronism compared with normal volunteers. The plasma cortisol and aldosterone concentrations did not, however, significantly change during alpha-hANP infusion in either the patients with Cushing's syndrome or those with primary aldosteronism. As synthetic alpha-hANP has a potent hypotensive effect in hypertensive patients with Cushing's syndrome and primary aldosteronism, a significant reduction in blood pressure and natriuresis seems to occur without affecting adrenocortical steroidogenesis.

Adult↗
PubMed1989

Production of GAWK (chromogranin-B 420-493)-like immunoreactivity by endocrine tumors and its possible diagnostic value.

GAWK (chromogranin-B 420-493) is a 74 amino acid peptide recently isolated from human pituitaries. Using two different antibodies (directed against GAWK [1-17] and [20-38] fragments) GAWK-LI was measured in tumors from 194 patients and in the plasma of 434 patients by RIA. The highest tissue concentrations of GAWK-LI were found in pheochromocytoma (GAWK [1-17]-LI, 18,173 +/- 3,915; GAWK [20-38]-LI, 17,852 +/- 2,763 [mean +/- SEM] pmol/g wet wt tissue; n = 9), which were at least ten times higher than any other tumors producing GAWK-LI. High concentrations of GAWK-LI were also found in other types of endocrine tumors including carcinoid, medullary carcinoma of thyroid, pancreatic, and ACTH-producing lung tumors. On the other hand, low concentrations of GAWK-LI were found in nonendocrine tumors. Plasma concentrations of GAWK-LI were found to be elevated in patients with endocrine tumor, but more so in those with pancreatic tumors than with pheochromocytomas. Plasma concentrations returned to normal after successful tumor removal. Chromatographic profiles of GAWK-LI in extracts of pheochromocytomas and normal adrenals showed high molecular weight peaks that were absent in the extracts of other endocrine tumors and normal pancreas, suggesting differential tissue-specific processing. Thus GAWK-LI is produced by a variety of endocrine tumors and may serve as a plasma tumor marker, especially in patients with pancreatic endocrine tumors.

Adrenal Gland Neoplasms↗
PubMed1989

Evidence for age-related change in plasma 19-hydroxyandrostenedione.

The steroid, 19-hydroxyandrost-4-ene-3, 17-dione (19-hydroxyandrostene-dione, 19-OH-A-dione) has been known to enhance the mineralocorticoid action of aldosterone. To investigate the age-related change in the plasma 19-OH-A-dione concentration, plasma 19-OH-A-dione, androst-4-ene-3, 17-dione (A-dione), aldosterone and cortisol of 38 non-hypertensive healthy subjects (18 young men and 20 aged men) measured by specific radioimmunoassays. The basal plasma 19-OH-A-dione and A-dione concentration in aged men was significantly lower than in young men (P less than 0.01). Moreover, there was found to be a positive correlation between plasma 19-OH-A-dione and A-dione (P less than 0.01). On the other hand, plasma aldosterone and cortisol in aged men showed a tendency to decrease, but no statistical significance compared to young men was observed. This study demonstrated that there was an apparent age-related decrease not only in plasma A-dione, but also in plasma 19-OH-A-dione, an amplifier or aldosterone action.

Adolescent↗
PubMed1989

[Familial scapuloperoneal-type myopathy associated with a marked elevation of serum creatine kinase and hepatomegaly].

The proband, a 17-year-old boy, was admitted to our department because of the difficulty in standing on heel. Physical examination revealed a marked weakness and atrophy of bilateral lower legs, especially anterior tibial muscles. Patellar and Achilles tendon reflexes were abolished. Marked hepatomegaly and moderate splenomegaly were noted on abdominal echogram and CT scanning. Serum creatine kinase, lactate dehydrogenase, GOT and GPT were markedly increased. There were no abnormal findings in thyroid function, serum lipid analysis and serum lactate level after ischemic forearm exercise test. EMG of anterior tibial and calf muscles showed a mixture of myogenic and neurogenic patterns and biopsy specimen of calf muscle was compatible with a dystrophic change. Liver biopsy specimen revealed no noticeable change except a slight ballooning of hepatocytes in light microscopy. However, electron microscopic examination showed a marked increase of intracellular vesicles and enlarged smooth ER in which low-density, cotton-like materials were contained. In family study, both his father and paternal uncle were also affected with advanced scapuloperoneal-type myopathy associated with a marked elevation of serum creatine kinase and hepatomegaly. The disorder differs from Miyoshi's distal muscular dystrophy, which shows an early involvement of flexor muscles in lower extremities and is inherited as an autosomal-recessive trait. Although the etiology of hepatomegaly in this case remains to be elucidated, the special findings on electron microscopic study imply the possibility of some unknown metabolic disorder involving both muscle and liver. This disease seems to be a new type of scapuloperoneal-type myopathy, probably having an autosomal-dominant inheritance.

Adolescent↗
PubMed1988

Glucose inhibits prostacyclin production by cultured aortic endothelial cells.

A reduction in production of prostacyclin (PGI2) by the cells in the vascular wall may play a role in the pathogenesis of atherosclerosis in diabetic patients. The present study was undertaken to evaluate the effect of glucose on PGI2 production by endothelial cells in vitro. It was shown that PGI2 production by cultured bovine aortic endothelial cells was significantly reduced in the presence of a high concentration of glucose (300 mg/dl) compared with physiological concentrations of glucose (100 mg/dl). In contrast, no reduction in PGI2 production was observed in cells cultured with equimolar mannitol, suggesting that glucose itself, rather than the effect of osmolality, inhibited PGI2 production by cultured endothelial cells. In addition, a high concentration of glucose also inhibited the proliferation of cultured endothelial cells.

Animals↗