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Biomedical subjects

T Nakada

Publications and source records attributed to T Nakada.

At least 451 records · Page 25Linked to original sources
PubMed1988

Central noradrenergic neurons and vascular non-collagen protein in the initial phase of two-kidney, one-clip renovascular hypertension.

Rats had been given intraventricular injection of 6-hydroxydopamine (6-OHDA) before clipping the unilateral renal artery (2K-1C) that caused selective ablation of the central noradrenergic neurons. Central catecholamines and the in vivo incorporation of 3H-proline into vascular non-collagen protein were determined in 2K-1C rats in the acute hypertensive stage. It is suggested that increased non-collagen protein synthesis in the mesenteric artery and the low level of hypothalamic norepinephrine concentration may participate in the development of 2K-1C hypertension in rats.

Animals↗
PubMed1988

Therapeutic results of primary aldosteronism with special reference to renal or renovascular lesions.

A study was made of 9 patients with primary aldosteronism due to aldosterone-producing adenoma (APA) and 8 subjects with idiopathic adrenal hyperplasia (IHA) to clarify the pathogenesis of sustained hypertension after surgical or non-surgical treatment. Following each treatment, a complete improvement of hypertension was obtained in 12 patients (6 APA, 6 IHA), while 5 (3 APA, 2 IHA) showed still hypertensive status. Renal or renovascular lesions were prominent only in the hypertension-unchanged group. Under regular sodium diet, the ratio of urinary excretion of sodium to creatinine of this hypertensive group was significantly lower than that of the hypertension-improved group. However, the results of other renal function tests were similar in both groups. After respective treatments, suppressed plasma renin activity and elevated plasma aldosterone concentration were improved in all patients. In addition, patients of both groups showed normal response of the renin-aldosterone system following diuretic and dietary induced sodium and volume depletion. Based on these findings, renal or renovascular lesions appear to play an important role in the pathogenesis of maintenance of hypertension in this disorder after respective treatments.

Adenoma↗
PubMed1988

Unilateral renal agenesis with or without ipsilateral adrenal agenesis.

We analyzed 7 patients with unilateral renal agenesis. The coexistence of unilateral renal agenesis with ipsilateral adrenal agenesis was confirmed surgically in 2 patients, 1 of whom had clinical features of Cushing's syndrome owing to adrenocortical adenoma of a solitary adrenal gland. It is imperative to suspect abnormalities of the ipsilateral adrenal gland when unilateral renal agenesis is encountered. Unilateral renal agenesis usually is asymptomatic. Recognition of this anomaly is essential for early correct diagnosis.

Adrenal Glands↗
PubMed1988

Catecholamine metabolism in pheochromocytoma and normal adrenal medullae.

The tissue contents of catecholamine, its precursor and its major metabolites were determined in 8 human pheochromocytomas and 26 normal adrenal glands. Pheochromocytomas contained significantly larger amounts of norepinephrine, dopamine, dihydroxyphenylalanine, tyrosine hydroxylase activity, metanephrine, normetanephrine and vanillylmandelic acid than did normal adrenal medullae. The content ratio of epinephrine/norepinephrine in normal adrenal medullae was significantly higher than that in pheochromocytomas but there were considerable individual variations in the metanephrine/normetanephrine and vanillylmandelic acid/3-methoxy-4-hydroxyphenylethylglycol ratios in pheochromocytomas. In normal adrenal medullae the tissue content of tyrosine hydroxylase activity correlated inversely with the tissue contents of epinephrine (r equals -0.78, p less than 0.001), norepinephrine (r equals -0.78, p less than 0.001) and total catecholamines (r equals -0.87, p less than 0.001), respectively but no significant relation was found between both parameters in pheochromocytomas. These results indicate the possible presence of a negative feedback mechanism of catecholamine via tyrosine hydroxylase in normal adrenal medullae but none in pheochromocytomas. In addition, the increased degradation catecholamine pathway in pheochromocytomas appears to be unstable compared to that in normal adrenal medullae.

Adrenal Gland Neoplasms↗
PubMed1988

F-19 MR imaging of glucose metabolism in the rabbit.

Noninvasive metabolic magnetic resonance (MR) imaging reflecting glucose metabolism in the aldose-reductase-sorbitol (ARS) pathway was performed in the rabbit head; after administration of the fluorinated glucose analogue 3-fluoro-3-deoxy-D-glucose (3FD-glucose), fluorine-19 images were generated. Images of 3FD-glucose showed significant 3FD-glucose uptake by adipose tissue, indicating its buffering effects in case of excess loads of glucose. Images of 3-fluoro-3-deoxy-D-sorbitol (3FD-sorbitol) demonstrated the spatial distribution of aldose reductase activities and significant sorbitol accumulation in the lens. Images of 3-fluoro-3-deoxy-D-fructose (3FD-fructose) showed preferential uptake of fructose by muscle tissue. The extremely low toxicity of 3FD-glucose indicates promise for its clinical application in metabolic imaging.

Aldehyde Reductase↗
PubMed1988

Unilateral renal agenesis associated with bicornuate uterus.

A case of bicornuate uterus associated with unilateral renal agenesis in a 45-year-old woman is reported. The embryologic problems of müllerian or wolffian ducts in this anomaly are discussed. By using radiological, nuclear or ultrasound methods unnecessary surgery could be evaded.

Female↗
PubMed1988

Testicular microlithiasis in male infertility.

Testicular microlithiasis was found in a 30-year-old infertile man. The literature is reviewed and the possible influence of testicular microlithiasis on male infertility is discussed.

Adult↗
PubMed1988

Superoxide dismutase activity in renal cell carcinoma.

Both Cu-Zn- and Mn-superoxide dismutase (SOD) activities were determined in renal cell carcinoma and tumor-uninvolved renal tissues in 25 patients with renal cancer. These enzymatic activities were similar in tumor and tumor-uninvolved renal tissues. The age of the patients, grade or stage of tumors had no apparent effect on SOD activities. Renal arterial embolization caused a slight decrease (p less than 0.05) in Cu-Zn-SOD activity in tumor tissues, but none in other enzymes in the same tissues, while renal arterial embolization reduced each SOD activity in tumor-uninvolved renal tissues (p less than 0.01 - p less than 0.001). Therefore the development of renal cell carcinoma is probably not related to the abnormality of renal SOD, but renal ischemic changes appear to lower each SOD activity in normal renal tissues.

Aged↗
PubMed1988

Hyperbaric oxygenation for experimental bladder tumor. I. Tissue oxygen tension of the rabbit bladder during hyperbaric oxygenation.

Although considerable advances have been made in the application of hyperbaric oxygenation (HBO) on tumor treatment in the recent past, many difficulties persist due to conflicting results and the understanding of its mechanism. We tested whether HBO treatment in clinical use could really influence the tissue concentration of oxygen in bladder or circulatory condition in animals. Eleven rabbits were treated with 1-3 atmospheric absolute pressures under an environment of air saturating 30-35% of oxygen for 90 min. Ten control animals were placed in the same chamber without providing HBO treatment. The tissue oxygen pressure in trigone or dome of the in HBO-treated group was significantly higher than that of the control group. A similar tendency was also noted in the arterial oxygen concentration to a greater extent, while regional blood flow in the bladder, mean arterial blood pressure and plasma volume were not significantly changed following HBO treatment. The use of HBO appears to offer some possibilities for the treatment of bladder tumor in the future.

Animals↗
PubMed1988

Effect of high-calcium diet on urinary oxalate excretion in urinary stone formers.

The effect of mild high-calcium diet or regular-calcium diet on urinary calcium excretion, urinary oxalate excretion, urinary calcium/creatinine ratio, urinary oxalate/creatinine ratio, and the probability of being a stone former (PSF) were studied in 85 patients with idiopathic urolithiasis. Intake of high-calcium diet for 5-6 days reduced (p less than 0.01-p less than 0.001) urinary oxalate excretion, urinary oxalate/creatine ratio and PSF in patients with idiopathic hypercalciuria. Under the regular-calcium diet, administration of 60 mg/day of pyridoxal phosphate for 3 months lowered (p less than 0.05-p less than 0.01) urinary oxalate excretion, urinary oxalate/creatinine ratio and PSF in patients with idiopathic hypercalciuria alone. From these findings, intake of mild high-calcium diet appears to be beneficial to decrease the urinary oxalate excretion and PSF in patients with idiopathic hypercalciuria. Pyridoxal phosphate has all the features of suppressing such risk factors for stone formation in patients with idiopathic hypercalciuria.

Adult↗
PubMed1988

Effect of vagus nerve cooling on hypercapnic and hypoxic ventilatory responses in anesthetized dogs.

We studied ventilatory responses under hypercapnic and hypoxic conditions in 18 lightly anesthetized dogs, using a vagus nerve cooling technique. One side of the cervical vagosympathetic trunks of dogs were previously severed, and a copper cooling probe was attached to the other side. When the cervical nerve was cooled below 7 degrees C, Hering-Breuer inflation reflex ceased. We found that when the vagus nerve was not cooled or cooled up to 7 degrees C, the respiratory frequency increased significantly in relation to hypercapnic gas inhalation. However, the increment of respiratory frequency was reduced by bilateral cervical vagotomy. On the other hand, the respiratory frequency in response to hypoxia increased significantly, even when bilateral vagotomy was done. The increment of the tidal volume in response to hypercapnic gas inhalation was reduced by the Hering-Breuer inflation reflex. We found that the effect of the vagus nerve on respiratory regulation was different between hypercapnic and hypoxic gas inhalation.

Animals↗
PubMed1988

[A case report of extragonadal germ cell tumor with special reference to VAB-6 therapy].

A 24-year-old man with a large abdominal mass in addition to the left lymph node swelling was referred to our clinic. Neither testicular nodulus nor overt evidence of tumor development in the scrotal cavity was confirmed by careful palpation and testicular biopsy. Values of lactate dehydrogenase, alpha-fetoprotein, human chorionic gonadotropin (HCG) and beta-HCG in the serum were markedly elevated. The specimen removed from the left cervical lymph node demonstrated mixed type of choriocarcinoma and embryonal carcinoma. A partial response near complete remission was achieved following the VAB-6 combination therapy (cyclophosphamide, vinblastine, actinomycin D, bleomycin, cis-platinum). The patient has been in good health with normal tumor markers and abdominal CT findings.

Adult↗