Biomedical subjects

Katsunobu Yoshioka

Publications and source records attributed to Katsunobu Yoshioka.

13 recordsLinked to original sources

PubMed2006

Phosphaturic mesenchymal tumor with symptoms related to osteomalacia that appeared one year after tumorectomy.

A 45-year-old man was admitted to our hospital because of bone pain and hypophosphatemia. He had undergone surgery 2 years previously for a "benign unclassified mesenchymal tumor" in the skull, but there were no clinical symptoms related to osteomalacia. His laboratory examination revealed low serum phosphate, high alkaline phosphatase, and normal calcium levels. The diagnosis of tumor-induced osteomalacia due to phosphaturic mesenchymal tumor mixed connective tissue variant (PMTMCT) was made by re-examining the pathologic specimens. Oral supplementation with phosphate and 1-25-dihydroxyvitamin D relieved his clinical symptoms and laboratory values returned to normal. However, subcutaneous administration of octreotide had no clinical effect. Clinicians and pathologists should be aware of the existence of PMTMCT especially nonphosphaturic or asymptomatic variants of this disorder.

Cranial Fossa, Posterior↗

PubMed2006

Multifocal fibrosclerosis combined with idiopathic retro-peritoneal and pericardial fibrosis.

A 70-year-old man who had been diagnosed with retroperitoneal fibrosis (RPF) was admitted to our hospital complaining of dyspnea. Imaging studies showed massive pericardial effusion. His condition deteriorated and pericardiostomy was performed. A biopsy of the pericardium revealed marked fibrosis with infiltration of lymphocytes, which was identical to RPF findings. A diagnosis of multifocal fibrosclerosis was made. Despite aggressive treatment, he died with clinical signs of cardiovascular failure. The autopsy specimen revealed proliferation of fibrosis with infiltration of lymphocytes in multiple organs. Even after successful decompression of urinary obstruction for RPF, long-term follow-up is necessary in these patients because of the possibility of other fatal complications such as pericardial fibrosis.

Aged↗

PubMed2005

Mast cell chymase in the ischemic kidney of severe unilateral renovascular hypertension.

Chymase degrades angiotensin I (AI) to form angiotensin II (AII), probably constituting a bypass of the renin-angiotensin cascade. Chymase activity increases in some vascular diseases. In the kidney, an increase in chymase activity was reported in an animal model of ischemic kidney of renovascular hypertension (RVH); however, no such evidence has been provided in humans. We treated a 64-year-old patient with severe unilateral RVH and atherosclerosis, for whom removal of the ischemic kidney was the only option. Using immunohistochemical staining, we investigated chymase activity in the removed kidney and associated artery and vein. An increase in chymase activity, together with mast cells infiltrating the interstitium, was observed where interstitial fibrosis was seen. In the renal artery, where severe atherosclerosis was seen, and also in the vein, mast cell infiltration in the adventitia was accompanied by chymase. The captopril test showed an increase in serum aldosterone level, with a concomitant increase in plasma renin activity and decrease in blood pressure. Because the decrease in blood pressure implies a decrease in circulatory AII levels, it is plausible that in this patient, chymase had a role in AII formation in the adrenal gland to stimulate aldosterone secretion. Thus, by means of captopril, AI levels increased, and chymase may have produced AII in loci tissues, which, in turn, stimulated aldosterone secretion. This is the first report of an increase in chymase activity in the interstitium of an ischemic kidney and renal artery and vein in a patient with RVH and atherosclerosis.

Angiography, Digital Subtraction↗

PubMed2005

Radiosurgery for nonfunctioning pituitary adenomas.

OBJECTIVE: We evaluated the effectiveness of gamma knife radiosurgery in the treatment of nonfunctioning pituitary adenomas. METHODS: Between January 1994 and December 1999, we treated 34 patients with nonfunctioning pituitary adenomas. Thirty-one of these patients were followed for more than 30 months. Their mean age was 52.9 years. All patients underwent resection before radiosurgery. In four patients, treatment was performed with staged radiosurgery. The treatment volume was 0.7 to 36.2 cm3 (median, 2.5 cm3). The treatment dose ranged from 8 to 20 Gy (median, 14.0 Gy) to the tumor margin. In 15 patients (48.4%), the tumor either compressed or was attached to the optic apparatus. The maximum dose to the optic apparatus was from 2 to 11 Gy (median, 8 Gy). RESULTS: Patients were followed for 30 to 108 months (median, 59.8 mo). The tumor size decreased in 18 patients (58.1%), remained unchanged in 9 patients (29.0%), and increased in four patients (12.9%). The 5-year actual tumor growth control rate was 93%. Among patients with tumor growth, two cases were secondary to cyst formation. Two patients (6.5%) required adrenal and thyroid hormonal replacement during the follow-up period after radiosurgery because of radiation-induced endocrinopathy. None of the patients sustained new cranial nerve deficits, which included optic neuropathy. CONCLUSION: In this series, radiosurgery had a high tumor growth control rate during the long-term follow-up period. Furthermore, we observed a low morbidity rate, with endocrinopathies and optic neuropathies. This low rate included even patients in whom the tumor compressed or was attached to the optic apparatus. We emphasize the necessity of long-term follow-up to evaluate late complications.

Adolescent↗

PubMed2004

Gamma knife radiosurgery for GH-secreting microadenoma with empty sella.

We report a case of a growth hormone secreting microadenoma associated with empty sella treated by gamma knife radiosurgery and we evaluate the effectiveness of radiosurgery for this lesion. A 58-year-old female complained of an acromegalic appearance for 10 years. Magnetic resonance imaging revealed an enlarged sella floor with a compressed, but slightly enlarged pituitary gland. Serum GH values were 8.52 ng/ml. From these results, we diagnosed the presence of a GH-secreting pituitary microadenoma with empty sella. Stereotactic gamma knife radiosurgery was performed to treat the adenoma. The treatment dose was 30 Gy for the tumour margin (50% isodose). The patient was monitored for 5 years without any reported problem. Serum GH values were gradually decreased to 4.1 and 3.5 ng/ml at 1.6 and 3 years. Serum GH values at 5 years after radiosurgery were 1.8 ng/ml within 2 h after glucose load and serum IGF-1 was normalized. We conclude that gamma knife radiosurgery can be an useful alternative treatment modality for GH-secreting adenoma with empty sella in the selected patients when surgery is contraindicated as the primary treatment.

Adenoma↗

PubMed2004

Blunted response of the renin-angiotensin system and nitric oxide synthesis related to sodium sensitivity in immunoglobulin A nephropathy.

Sodium sensitivity of blood pressure appears before hypertension in immunoglobulin A nephropathy, as glomerulosclerosis and interstitial damage progress. To find whether this sensitivity is related to NO and the renin-angiotensin system, we examined 39 such patients without hypertension after they followed a diet with an ordinary sodium level for 1 week and a sodium-restricted diet for 1 week, in random order. Patients were divided into two groups at the median of their sodium sensitivity index (<0.040, n=19; > or =0.040 mmHg/mEq per day, n=20), calculated as the reciprocal of the slope of the pressure-natriuresis curve drawn by linkage of two datum points obtained during the different diets. Urinary excretion of NOx (NO2 and NO3), plasma renin activity, and serum aldosterone were measured. NOx was higher in the low-index group than in the high-index group with the ordinary sodium level, but not during sodium restriction. NOx was correlated negatively and significantly with the index with the ordinary sodium level (p=-0.406), but correlation in changes during sodium loading was not significant (p=-0.195). Changes in plasma renin activity and serum aldosterone during sodium restriction were greater in the low-index group than in the high-index group. The changes in renin activity and aldosterone were correlated negatively and significantly with the index (p=-0.573 and -0.499, respectively). These results indicate that impairment of NO synthesis and a blunted response of the renin-angiotensin system are attributable to the altered sodium sensitivity of blood pressure in patients with immunoglobulin A nephropathy.

Adult↗

PubMed2003

Nephrogenic diabetes insipidus due to hydronephrosis in a patient with a solitary kidney.

A 68-year-old man with a history of nephrectomy of the right kidney was admitted to our hospital with a 1-month history of polyuria (> 41 per day). He also exhibited hyposthenuria, which was unresponsive to treatment with exogenous vasopressin. Radiographic examination revealed partial obstruction of the left ureter and moderate hydronephrosis. The cause of the obstruction was cancer of the ureter. After drainage using a nephrostomy tube, the polyuria and hyposthenuria were gradually resolved. This is the first known case of nephrogenic diabetes insipidus due to hydronephrosis in a patient with a solitary kidney.

Aged↗

PubMed2003

Treatment of lymphocytic hypophysitis by high-dose methylprednisolone pulse therapy.

A 26-year-old woman 3 months post-partum was admitted to our hospital suffering from gross visual disturbance. Magnetic resonance imaging (MRI) revealed a pituitary mass, extending into the suprasellar cistern, with intense gadolinium enhancement. Lymphocytic hypophysitis (LHy) was suspected, and the patient received high dose methylprednisolone pulse therapy (HDMPT). Her visual disturbance was dramatically ameliorated on the first day following initiation of HDMPT, and MRI revealed marked mass reduction. Her pituitary function recovered 6 months after therapy. This case report suggests that HDMPT proved effective for mass reduction of severe LHy and could obviate the need for a useless surgery.

Adult↗

PubMed2003

Transient central diabetes insipidus in pregnancy with a peculiar change in signal intensity on T1-weighted magnetic resonance images.

A 38-year-old woman was admitted with severe thirst and polyuria at 31 weeks' gestation. The plasma concentration of vasopressin (AVP) was very low (0.73 pg/ml) under conditions of high plasma osmolality (316 mOsm/ kg). T1-weighted magnetic resonance (MR) images revealed enlargement of the pituitary posterior lobe with absence of the hyperintense signal. After delivery, restoration of the hyperintense signal was demonstrated. This depletion-repletion process, which reflects the decrease and increase in amount of neurosecretory granules, is recognized in the case of transient central diabetes insipidus during pregnancy. We consider that an increase in cystine-aminopeptidase (CAP) activity is implicated in the pathogenesis.

Adult↗

PubMed2002

Glycemic response during exercise after administration of insulin lispro compared with that after administration of regular human insulin.

To examine the glycemic response during exercise after administration of short-acting insulin lispro, we compared changes in plasma glucose concentrations during exercise performed by patients with diabetes after the administration of either insulin lispro or regular human insulin. Seven patients with diabetes (two with type 1 and five with type 2) participated in this study. Each of the insulin-depleted subjects received the same number of units of either insulin lispro or regular human insulin, delivered subcutaneously to the abdomen. The next day, each subject received a similar injection of the solution not previously administered. After each injection, the subjects were fed a standard meal of approximately 9 kcal/kg body weight. One hour after eating the test meal, the subjects performed 30 min of cycle ergometer exercise at 50% maximal oxygen uptake. Plasma glucose, insulin, glucagon, growth hormone (GH), and catecholamine concentrations were then measured at specific intervals. Insulin concentrations were higher and peaked earlier after administration of insulin lispro than after administration of regular human insulin. The length of time, needed to reach minimum plasma glucose concentration after exercise was begun, was significantly shorter after administration of insulin lispro, and the percentage of plasma glucose decrease induced by exercise relative to the peak concentration was significantly greater. No differences were found in the concentration changes of counterregulatory hormones between the insulin lispro data and the regular human insulin data. Compared with regular human insulin, insulin lispro induces a more rapid and greater decrease in plasma glucose concentration during exercise because of its faster absorption.

Adult↗

PubMed2002

Complete adrenocorticotropin deficiency after radiation therapy for brain tumor with a normal growth hormone reserve.

A 34-year-old man with neurofibromatosis type 1, who had received radiation therapy after the excision of a brain tumor 5 years earlier, was admitted to our hospital with vomiting and weight loss. Cortisol and adrenocorticotropin (ACTH) were undetectable before and after administration of 100 microg corticotropin releasing hormone. The level of growth hormone without stimulation was 24.7 ng/ml. We diagnosed him to have complete ACTH deficiency attributable to radiation therapy. This is the first known case of a patient with complete ACTH deficiency after radiation therapy and a growth hormone reserve that remained normal.

Adrenal Insufficiency↗

PubMed2002

An insulinoma for which secretin test and selective arterial calcium injection test were useful.

A 76-year-old woman suffered from somnolence while fasting for almost 2 years. Fasting plasma glucose (FPG) (40 mg/dl) and the immunoreactive insulin (IRI) level (8.8 microU/ml) were not compatible with Fajan's ratio or Turner's ratio observed in typical insulinoma. The secretin test showed no response to insulin secretion, suggesting the presence of insulinoma. Abdominal dynamic computed tomography (CT) revealed a 12-mm hypervascular lesion in the head of the pancreas. A selective arterial calcium infusion test (SACI) was performed, during which IRI in the hepatic venous blood was measured following selective intraarterial calcium infusion. An increase in IRI levels in the gastroduodenal and superior mesenteric arteries suggested the presence of a functional insulinoma in the head of the pancreas. Enucleation of the tumor improved FPG and IRI levels to 138 mg/dl and 3.8 microU/ml, respectively. After surgery, a secretin test showed a 5-fold increase in IRI levels, suggesting normal beta cell function. This case illustrates the value of the secretin test for the diagnosis of insulinoma and for the postoperative assessment of beta cell function. It further illustrates the value of the SACI for localizing an insulinoma.

Aged↗

PubMed2002

Impact of diabetes on coronary stenosis and coronary artery calcification detected by electron-beam computed tomography in symptomatic patients.

OBJECTIVE: Ischemic heart disease is a pivotal complication for diabetic patients. Electron-beam computed tomography (EBCT) represents the only noninvasive method that allows for accurate quantification of coronary artery calcification that reflects underlying atherosclerotic disease. Although coronary calcium score (CCS) cut points that predict the presence of angiographic stenosis have been established in nondiabetic individuals, it is not known whether coronary calcifications in diabetic patients are associated with the presence of significant coronary stenoses. In this study, we evaluated the relationship between coronary calcifications and angiographic stenosis in symptomatic patients with or without type 2 diabetes. RESEARCH DESIGN AND METHODS: In this study, 282 patients (204 men and 78 women) with chest pain, including 101 diabetic patients and 181 nondiabetic patients (mean age 63 +/- 9.6 years), underwent coronary angiography and EBCT with determination of CCS using Agatston's method. Luminal stenosis >or= 50% was defined as significant coronary stenosis. RESULTS: Angiography identified 205 patients with significant stenoses (89 of 101 diabetic patients, 114 of 181 nondiabetic patients). The sensitivity and specificity of EBCT to detect significant coronary stenosis were not significantly different between diabetic and nondiabetic patients. In diabetic patients, a CCS >or=90 was associated with 75% sensitivity and 75% specificity, whereas a CCS >or=200 was associated with 64% sensitivity and 83% specificity. CONCLUSIONS: We demonstrated that calcification of the coronary arteries in symptomatic diabetic patients is well associated with severity of coronary stenosis, as in nondiabetic patients.

Adult↗