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Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 631 records · Page 35Linked to original sources
PubMed1988

[The protective effect of simultaneous selenium administration on acute cadmium toxicity and metallothionein].

The present study was conducted to elucidate the protective action of simultaneous selenium administration against acute cadmium toxicity. The remarkable testicular damages caused by cadmium, that is, hemorrhagic inflammation, atrophy and necrosis, were lessened by simultaneous selenium administration. Cadmium concentration in blood, especially in plasma, increased significantly during the early period after cadmium administration with selenium. Cadmium and selenium in plasma were found in the same fractions of high molecular weight reported by previous workers as the high molecular weight complex containing cadmium and selenium. Cadmium in testis was also noted in the high molecular weight fraction during the early period. However, cadmium in the high molecular weight fraction of plasma and testis were unstable and decreased rapidly by lapse in time. Cadmium concentration in liver was lower than that in the group administered cadmium alone during the increasing phase of plasma cadmium. However, in contrast with the decreased cadmium level in plasma, cadmium in liver and testis increased gradually. Cadmium increased in liver and testis were also found in the metallothionein fraction. In the testis protected from acute cadmium toxicity, the inhibitory effect of glutathione S-transferase activity by cadmium was not detectable and the activity was maintained at the level of the control (saline administered group). Moreover, the increased cadmium in the metallothionein fraction was related to the decrease of cadmium in the high molecular weight fraction of the testis homogenate. In addition, a positive correlation was observed between metallothionein concentration and glutathione S-transferase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The region of medial forebrain bundle is involved in tonic maintenance of arterial pressure and heart rate.

The role of the medial forebrain bundle (MFB) in central regulation of cardiovascular system was studied in freely moving rats. Injection of lidocaine into the ventral, but not other portions of the MFB, produced transient (approximately ten minutes) pressor and tachycardic responses. These responses resulted from an increase in sympathetic tone, since they were abolished by ganglionic blockade. The pressure response was attenuated by alpha-adrenoceptor blockade and both pressor and tachycardic responses were diminished by beta-adrenoceptor blockade. Electrolytic lesion of the same site caused long lasting pressor and tachycardic responses. Injection into the MFB of the excitatory amino acids, kainate (KA) and N-methyl-D,L-aspartate (NMDA) produced pressor and tachycardic responses accompanied by behavioral excitation, whereas no effects were produced by L-glutamate. The cardiovascular responses induced by KA and NMDA were abolished by ganglionic blockade. These results suggest that a selective region of MFB contains fibers of passage and/or cell bodies, with receptor specificity for excitatory amino acids, that are capable of influencing sympathetic sympathetic control of arterial pressure.

Amino Acids↗
PubMed1988

Clinical evaluation of tumour imaging using 99Tc(V)m dimercaptosuccinic acid, a new tumour-seeking agent.

Considering the favourable nuclear properties of 99Tcm over 67Ga, we have developed a new tumour-seeking agent, 99Tc(V)m dimercaptosuccinic acid (Tc(V)-DMSA). In order to evaluate the clinical usefulness of Tc(V)-DMSA scintigraphies, 492 patients were studied with Tc(V)-DMSA, and in some cases, where possible, the results were compared with conventional 67Ga citrate scintigraphies. There was a high degree of usefulness of Tc(V)-DMSA in patients with head and neck tumours, medullary thyroid carcinomas and soft tissue tumours. But in patients with carcinomas of the lung, liver and gastrointestinal tract, malignant melanoma and lymphoma, Tc(V)-DMSA was of no or little use.

Drug Evaluation↗
PubMed1988

Sipple's syndrome with liver tumors examined by iodine-131 MIBG and technetium-99m(V)-DMSA.

This case report describes the localization and categorization of tumors using 99mTc(V)-dimercaptosuccinic acid and [131I]metaiodobenzylguanidine scans in a very uncommon case of medullary thyroid carcinoma associated with pheochromocytoma (Sipple's syndrome) and hepatocellular carcinoma. Technetium-99m(V)-dimercaptosuccinic acid showed accumulation only in medullary thyroid carcinoma, but [131I]metaiodobenzylguanidine scans were positive in both medullary thyroid carcinoma and pheochromocytoma. In advanced Sipple's syndrome, combined use of [99mTc(V)]dimercaptosuccinic acid and [131I]metaiodobenzylguanidine may be useful for the categorization of tumor mass lesions and planning appropriate therapy.

3-Iodobenzylguanidine↗
PubMed1988

Electroencephalographic effects of the new antidepressant paroxetine in the rabbit.

The electroencephalographic (EEG) effect of (-)-trans-4-(4'-fluorophenyl)-3-(3',4'-methylene-dioxyphenoxy-met hyl)piperidine hydrochloride (paroxetine, BRL 29060A) a new antidepressant, was investigated in conscious rabbits with chronic electrode implants and was compared with those of imipramine and amitriptyline. Paroxetine induced an arousal pattern of the spontaneous EEG consisting of low voltage fast waves in the cortex and synchronization of hippocampal theta waves with decreased amplitude, while imipramine and amitriptyline elicited drowsy patterns of the spontaneous EEG. Paroxetine failed to suppress the EEG arousal responses induced not only by auditory stimulation but also by electrical stimulation of the mesencephalic reticular formation, centromedian thalamus and posterior hypothalamus, whereas imipramine and amitriptyline markedly inhibited these responses. The EEG arousal response induced by i.v. injection of physostigmine 0.2 mg/kg was slightly enhanced by paroxetine, while the response was significantly suppressed by imipramine and amitriptyline. Paroxetine, imipramine and amitriptyline showed no significant effect on the photic driving response and recruiting response. Paroxetine did not show any effects on the limbic afterdischarges elicited by either hippocampal or amygdaloid stimulation, while imipramine and amitriptyline caused an initial suppression followed by slight enhancement of these afterdischarges. These results indicate paroxetine to be an antidepressant of a new type which induces a sustained arousal pattern of the spontaneous EEG and has no central anticholinergic action.

Amitriptyline↗
PubMed1988

[Modified surgical methods in gastrointestinal and lung cancers].

There are such cancers as that they are rarely detected during an early stage, they show poor prognosis even though being small in size, and that it is difficult to perform reduced operation on them for the purpose of functional conservation. Cancers of the lung, esophagus, rectum, liver, gallbladder and pancreas are included in these cancers for the present. Bronchoplasty for lung cancer, nervous conservation for rectum cancer, and conservative operation to keep a natural anus have been widely performed. At the present time, it has been still difficult to undertake reduced operation for the treatment of esophageal cancer and liver-biliary-pancreatic cancer without damages to the radicalness. Unfortunately, anticancer agents or irradiation has shown no satisfactory effects on the above mentioned cancers. However, radial effects are now obtained from some techniques; they are, laser irradiation for very early cancer of the bronchus and esophagus, and plypectomy for small and early rectal cancer.

Bronchi↗
PubMed1988

[Matas procedure in the treatment of spontaneous carotid cavernous sinus fistula: a complication of retinal hemorrhage].

We herein report three cases of the dural internal type of spontaneous carotid cavernous sinus fistula (SCCF) which seemed to be improved by the Matas procedure. Sequential cerebral angiography revealed that thrombosis formation in the peripheral side of the draining vein resulted in a closure of the fistula. During this course of spontaneous regression, retinal findings were transiently exacerbated in some cases. The retinal hemorrhage seemed to be induced by central retinal vein occlusion and hypoxic retinopathy which preceded the spontaneous regression of SCCF. It was confirmed that the Matas procedure should be tried as the first choice for the treatment of SCCF, particularly in the dural internal type. However, fundus findings must be carefully monitored.

Arteriovenous Fistula↗
PubMed1988

Inhibitory effects of aminoglycosides on renal protein phosphorylation by protein kinase C.

Aminoglycosides such as neomycin are commonly prescribed antibiotics; however, there is associated serious damage to the kidney. We examined the effect of aminoglycoside antibiotics on renal protein phosphorylation and found that neomycin selectively inhibited Ca++-activated, phospholipid-dependent phosphorylation of 88-kDa protein in cell lysates of the rabbit kidney. Fifty percent inhibition of phosphorylation of this protein occurred with 5 X 10(-5) to 1 X 10(-4) M neomycin. In living PtK2 cells, neomycin dose-dependently inhibited 12-O-tetradecanoyl-phorbol-13-acetate-induced phosphorylation of 88 K Da protein. This drug also inhibited phosphorylation of exogenous protein catalyzed by protein kinase C, isolated from rabbit kidney in vitro. In contrast, neomycin had little or no inhibitory effect on cyclic GMP-dependent protein kinase, cyclic AMP-dependent protein kinase, casein kinase I, casein kinase II and Ca++-calmodulin-dependent myosin light chain kinase. Whereas activity of protein kinase C was inhibited 65% by neomycin (0.1 mM) at pH 5 to 7, inhibition decreases to 33% at pH 8 and to zero at pH 9. The potencies of a series of aminoglycoside antibiotics to inhibit the kinase agreed well with number of ionizable amino groups of compounds (gamma = 0.99) and this also approximates their known nephrotoxic potential; amikacin less than or equal to kanamycin less than gentamycin less than or equal to tobramycin less than neomycin. As aminoglycoside antibiotics present in the kidney after administration of toxicological doses (10(-2) M) will inhibit the effects of protein kinase C, the aminoglycoside antibiotics-induced nephrotoxicity is discussed in relation to inhibition of intracellular protein kinase C.

Aminoglycosides↗
PubMed1988

Reduction of doxorubicin-induced cardiotoxicity in mice by taurine.

The effect of taurine on doxorubicin-induced cardiotoxicity was examined in mice. A single intraperitoneal injection of doxorubicin (15 mg/kg) produced a significant elevation of calcium and lipoperoxide content at 72 hr, as well as a significant depletion of creatine phosphokinase, glutamic oxaloacetic transaminase and lactate dehydrogenase activities at 48 hr and glutathione peroxidase activity at 24 hr in the myocardium. These results suggest that a substantial myocardial damage had occurred. All biochemical alterations except depletion of glutathione peroxidase, were markedly attenuated by the combined oral and intraperitoneal administration of taurine. Taurine significantly improved the survival rate of the mice treated with doxorubicin. These results demonstrate that taurine antagonized doxorubicin-induced cardiotoxicity.

Animals↗
PubMed1988

[Evaluation of osteoporosis associated with menopause and oophorectomy by microdensitometry].

Osteoporosis is one of the diseases affecting the elderly that is receiving increasing attention. The present study employed microdensitometry (MD) to evaluate osteoporosis in a relatively younger group of persons aged less than 60. The relationship of this disease to menopause or a history of oophorectomy was also studied. Of 149 cases, this condition was recognized in 33 (22.1%), demonstrating the effectiveness of the MD method. Of 41 premenopausal subjects, osteoporosis was recognized in 8, (19.5%), as compared to 5 of 36 postmenopausal subjects (13.9%), suggesting that the prevalence of this condition was also low in the postmenopausal group and thus suggesting that the menopause was not necessarily a point of importance in the development of this condition. Furthermore the condition was recognized in 20 of 72 cases (27.8%) with a history of total oophorectomy, showing a higher rate than in either the premenopausal or postmenopausal groups. In addition a direct correlation was recognized between the prevalence of osteoporosis and the period since total oophorectomy. These results suggested a strong relationship between total oophorectomy and the occurrence of osteoporosis.

Absorptiometry, Photon↗
PubMed1988

Low serum creatinine levels in severe hepatic disease.

For five years, eight patients had abnormally low serum concentrations of creatinine. All patients presented with severe hepatic failure, which was due to fulminant hepatitis in seven patients and to advanced primary biliary cirrhosis in one patients. The serum urate (as uric acid) concentration was also low in seven patients. Endogenous creatinine clearance was increased in all patients (2.38 to 14.75 mL/s [143 to 885 mL/min]). However, inulin clearance measured in four patients was reduced (25 to 32 mL/min) and the creatinine-to-inulin clearance ratio ranged from 4.5 to 9.9. This range can be explained largely by an increased tubular secretion of creatinine related to body fluid expansion caused by a large fluid infusion. Renal function would be extremely overestimated when assessed from serum concentrations or clearance of creatinine in such patients.

Creatinine↗
PubMed1987

Early gastric carcinoma with special reference to macroscopic classification.

During a period beginning in 1946 and ending in October of 1978, 1000 cases of solitary early gastric carcinoma were operated on at the Cancer Institute Hospital, Tokyo, Japan. The clinical characteristics and the macroscopic and chronological changes were studied in these cases. Early gastric carcinoma comprised one third of all resected gastric carcinoma. If early gastric carcinoma was divided into two groups, the depressed and the elevated, the former was more common. By location, the depressed type lesions were more frequently seen in the middle third of the stomach and the elevated type lesions in the lower third. By age, distribution of the elevated type lesions showed a peak with a mode at the age of 60 to 69 years and of the depressed type, a plateau with a mode at the age of 50 to 59 years. The relative incidence of the elevated type of gastric carcinoma to the depressed type was one to four. In depth of invasion, the mucosa and the submucosa were equally involved. Lymph node metastases were encountered in 12.7% of early gastric carcinoma cases. The incidence of positive nodes in mucosal carcinoma was 3.4% and that of submucosal lesions was 21.7%. Of the elevated type carcinoma, 20.9% of the cases had positive nodes. The 5-year survival rate of the patients with surgery for cure was 93.8% in contrast to 56.5% of those with palliative resection.

Aged↗