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Biomedical subjects

T Hirata

Publications and source records attributed to T Hirata.

At least 343 records · Page 19Linked to original sources
PubMed1991

[Spontaneous carotid-cavernous sinus fistula; analysis of 16 cases].

We have encountered 16 cases with spontaneous carotid-cavernous sinus fistula. According to the classification reported by Barrow, one case was type A; direct shunt between the internal carotid artery (ICA) and the cavernous sinus (CS), 5 were type B; dural shunt between meningeal branches of the ICA and the CS, 6 were type C; dural shunt between meningeal branches of the external carotid artery (ECA) and the CS, and 4 were type D; dural shunt between meningeal branches of both ICA and ECA and CA. Of all cases, 8 patients with low-flow fistula treated conservatively improved spontaneously. Three patients were treated with irradiation. Consequently, good results were obtained in 2 cases, but no improvement could be obtained in the remaining one with high flow fistula. Another four patients were treated with intravascular embolization via the ECA, and their symptoms improved. But one patient treated with Ivalon embolization died because of complicated pulmonary embolism. As spontaneous CCF had a high rate of spontaneous regression of symptoms, conservative treatment such as Matas maneuver or irradiation should be recommended at first for low flow cases in type B, C, and D. Surgical therapy such as intravascular embolization should be carried out for high-flow cases in type C and D.

Adult↗
PubMed1991

[Effects of nitroglycerin upon myocardial metabolism after open heart surgery].

The effects of intravenous administration of nitroglycerin (TNG) on hemodynamics and myocardial metabolism after open heart surgery were evaluated in 22 patients without ischemic heart disease. On 12 hours after starting the continuous infusion of TNG at a rate of 0.2 micrograms/kg/min on 10 patients (TNG group), coronary blood flow (CBF) increased (p less than 0.01) and myocardial oxygen metabolism improved remarkably. However, anaerobic metabolism still existed in TNG group and no significant difference between TNG group and Control group even after 12 hour continuous drug infusion. From these studies, it was concluded that the intravenous administration of TNG at a rate of 0.2 microgram/kg/min increased CBF, however did not improve myocardial metabolism after open heart surgery possively probably because of changes in coronary collateral function.

Adult↗
PubMed1991

[Non-occlusive mesenteric infarction following cardiovascular surgery].

In the majority of patients with intestinal infarction, it is generally agreed that the occlusion of mesenteric arteries or vein is the primary etiologic factor; however, some showed no evidence of thrombosis, embolization or vasculitis as the causative factor. In many patients, this particular type of infarction is the terminal event of the episode. From October 1977 to December 1986, 24 patients with mesenteric infarction were investigated following cardiovascular surgery in our institute. Among them, 15 were diagnosed with organic vascular occlusion; however, the other 9 showed no evidence of thromboembolism or any other organic vascular occlusive lesion of mesenteric vessels and were diagnosed as non-occlusive mesenteric infarctions. All of these patients were in severe cardiac failure (LOS) postoperatively. There was no typical symptom, although abdominal fullness and diarrhea were the major and consistent findings. In blood chemical analysis, the enzymatic levels such as serum GOT, LDH and CPK were significantly elevated and discrepancy between serum GOT and serum GPT was observed. In this clinical situation, it was difficult to establish a correct diagnosis mainly because of the few signs and symptoms present relating to the mesenteric infarction. On the other hand, when the correct diagnosis was made, these patients were too critically ill to be treated conservatively. The outcome of these patients was grave and all of them died which showed 100% of mortality rate. The conservative management did not produce favorable progress, which accelerated LOS and prevented patients from recovering from cardiac failure. The aggressive surgical approach to this particular type of acute mesenteric ischemia might have offered an improved prognosis from these catastrophic events.

Adult↗
PubMed1991

[Fusiform and dissecting aneurysm of the vertebrobasilar systems: differential diagnosis].

Fusiform aneurysms (FA) and dissecting aneurysms (DA) of the vertebro-basilar systems have been thought to be rare, but recently reports of these aneurysms have increased. The differential diagnosis between FA and DA is requisite for deciding therapy or for prognosis, but it is often difficult to distinguish these aneurysms even if angiographies are conducted. The authors have treated 6 cases with FA and 5 cases with DA during the past 17 years. As the initial symptom, subarachnoid hemorrhage (SAH) was noted in all 6 cases with FA. On the other hand, 2 cases of SAH, 2 cases of brain stem infarction, and 1 case of ischemic attack were noted in DA cases. The aneurysmal locations of FA were at the vertebral artery (VA) in all 6 cases, and those of DA were at the VA in 3 cases and at the basilar artery (BA) in 2 cases. As angiographic findings of DA, pearl & string signs were demonstrated in 3 cases, and retention of contrast medium was noted in 3 cases. Diagnosis of FA is comparatively easy on angiography but when angiospasm exists, it is difficult to differentiate DA from FA. Consequently, repeated angiography is recommended. MR imaging findings of 2 cases with FA were compared with those of 3 cases with DA. No abnormal findings, excepting a dilatation of the signal-void area corresponding to the arterial blood flow were shown in FA, but various abnormalities were detected in all of the 3 cases with DA. Namely, an intimal flap and a double lumen in 1 case, intra-mural hematoma in 1 case, and a hematoma adjacent to the parent artery in 2 cases were demonstrated. Thus, MR imaging was thought to be a useful means for distinguishing between FA and DA.

Adult↗
PubMed1990

Dissecting and fusiform aneurysms of vertebro-basilar systems. MR imaging.

The magnetic resonance (MR) findings of three cases with vertebro-basilar dissecting aneurysms (DA) were compared with those of two cases with vertebro-basilar fusiform aneurysms (FA). No abnormal findings, excepting a dilatation of a signal-void area corresponding to the arterial blood flow, were shown on the MR images in the patients with a FA. In contrast to the FA cases, various abnormalities were detected by the MR studies in all three DA cases. An intimal flap and a double lumen were demonstrated in one case. An intra-mural hematoma was shown in one case. A hematoma neighboring the parent artery was demonstrated in two cases. MR imaging was thought to be useful for detecting intracranial vascular lesions, such as a DA, and for discriminating between a DA and a FA.

Adult↗
PubMed1990

Xanthogranulomatous cholecystitis in an infant with obstructive jaundice.

We describe a female infant with obstructive jaundice due to inflammatory stenosis of the choledochus. It was surrounded and narrowed by a xanthogranulomatous lesion, extending from xanthogranulomatous cholecystitis (XGC). The obstructive jaundice was released by a cholecystectomy, resection of the choledochus, and hepaticojejunostomy. This is the first reported case of infantile XGC associated with obstructive jaundice.

Cholecystitis↗
PubMed1990

Cell surface molecule A5: a putative involvement in retinal central connection.

We produced monoclonal antibodies against Xenopus tadpole visual centers and obtained an antibody named A5 (MAb-A5). The antigen of MAb-A5 is a cell-surface-related protein molecule (A5 antigen). Immunohistochemistry using MAb-A5 and an eye-transplantation experiment suggest the involvement of A5 antigen in specific cell recognition between retinal axons and their targets.

Animals↗
PubMed1990

Anticancer activity of free gamma-linolenic acid on AH-109A rat hepatoma cells and the effect of serum albumin on anticancer activity of gamma-linolenic acid in vitro.

The cytotoxicity of gamma-linolenic acid (C18:3n-6) against rat hepatoma AH-109A cells and the effect of bovine serum albumin (BSA) on its toxicity were examined in culture. The proliferation of AH-109A cells, evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, was significantly suppressed by gamma-linolenic acid above 5 micrograms/ml concentration in serum-free culture medium. However, its toxicity was reduced by supplement of BSA. Similar observation of reduced toxicity by BSA was shown by the method of trypan blue dye exclusion and a colony formation assay. The cytotoxicity of gamma-linolenic acid was correlated closely with the concentration of unbound (free) gamma-linolenic acid. Production of thiobarbituric acid reactive material, one of the indicators of lipid peroxidation, was stimulated by gamma-linolenic acid and inhibited by BSA. These results suggested that the presence of albumin suppressed the cytotoxicity of the free fatty acid.

Animals↗
PubMed1990

Synthesis and biological evaluation of quinocarcin derivatives.

Cyanation of quinocarcin readily opened the oxazolidine ring to provide DX-52-1 (2), which was a key compound in the synthesis of quinocarcin derivatives. Various electrophilic reactions toward aromatic ring of DX-52-1 were examined, and 10-substituted (e.g., halogen, nitro, formyl, cyano, hydroxy, etc.) analogs were prepared. Dehydrocyanation of the derivatives could be achieved to reproduce the oxazolidine ring upon treatment with HCl or AgNO3. 10-Chloride 10 and 10-bromide 11 were the most promising among the derivatives prepared. Antitumor activity of 10 was extended to B-16 melanoma.

Animals↗
PubMed1990

Studies on cardiotonic agents. III. Synthesis of 1-[1-(6,7-dimethoxy-4-quinazolinyl)-4-piperidinyl]-3-substituted 2-imidazolidinone and 2-imidazolidinethione derivatives.

A series of 1-[1-(6,7-dimethoxy-4-quinazolinyl)-4-piperidinyl]-3-substituted 2-imidazolidinone and 2-imidazolidinethione derivatives was synthesized and examined for cardiotonic activity in anesthetized dogs. Alkylation of the 2-imidazolidinone (1) afforded the N-alkylated products, while alkylation of the 2-imidazolidinethione (12) afforded the S-alkylated derivatives accompanied with a small quantity of the N-alkylated products. The N-alkylated derivatives showed generally potent activity, and the S-alkylated ones exhibited weak activity. Insertion of an alkyl group between the piperidine and the imidazolidinone moiety generally resulted in a fall in activity.

Animals↗
PubMed1990

Studies on cardiotonic agents. IV. Synthesis of novel 1-(6,7-dimethoxy-4-quinazolinyl)piperidine derivatives carrying substituted hydantoin and 2-thiohydantoin rings.

A series of novel 1-(6,7-dimethoxy-4-quinazolinyl)piperidines carrying substituted hydantoin and 2-thiohydantoin rings was synthesized and examined for cardiotonic activity in anesthetized dogs. Introduction of isopropyl and sec-butyl group at the 5-position of the hydantoin and thiohydantoin rings led to potent inotropic activity. Effects of insertion of an alkyl chain between the piperidine and the hydantoin rings were also examined. The structural requirements necessary for optimal cardiotonic activity within the series were investigated.

Animals↗
PubMed1990

Synthesis of quinone derivatives of quinocarcin.

O-Demethyl-DX-52-1 (3a) was prepared from quinocarcin (1) in two steps (cyanation and O-demethylation). Upon treatment with Fremy's salt, 3a and its esters 3b, 3c afforded the desired quinone 4-6 in good yields. Various substituted quinones 12-37, 47-50 were prepared from 4-6 by Thiele acetylation followed by hydrolysis of acetates and halogenation, by direct addition of amine, alcohol and mercaptan, and by epoxidation and subsequent opening of the epoxide ring with aniline. The quinonemonoketals 39b and 40 were obtained from the corresponding methoxyphenols 7b and 38b. Addition of hydroxylamine gave the quinoneoxime 44 regiospecifically. The antitumor activity of the bis-methylthioquinone (37) among the various derivatives was the most promising.

Animals↗
PubMed1990

Tumors at the trigone of the lateral ventricle--clinical analysis of eight cases.

Tumors at the trigone of the lateral ventricles are relatively rare. The authors have operated on eight cases with trigonal tumors during a 10-year period. Four cases were true intraventricular tumors arising from the ventricular walls, consisting of two meningiomas, one cavernous angioma, and one choroid plexus papilloma. On the other hand, the remaining four cases were paraventricular tumors originating in the adjacent brain and consisted of three astrocytomas and one glioblastoma multiforme. Although these trigonal tumors were readily detected with computed tomographic (CT) scanning, differential diagnosis was difficult because of their similar appearances on CT scans. The initial symptoms were headache in seven, and the neurological examination revealed personality changes, choked disc, visual field defects, hemiparesis, etc., in four, and no deficits in the remaining four cases. All cases were operated on via superior or middle temporal gyrus incision, and the surgical results were good except for one case who died of postoperative brain edema. In the four cases with tumors located in the dominant hemisphere, two were left with sensory aphasia, dyslexia, dyscalculia, and hemianopsia which improved within 6 months. In these two cases, postoperative CT scans revealed cerebrospinal fluid retention with severe edema along the surgical route which disappeared spontaneously within 3 months. We consider that the temporal gyrus incision was the safest approach, even though the tumor was located in the dominant side.

Adolescent↗
PubMed1990

[Treatment of asynchronous bilateral renal cell carcinoma. On our experience of enucleation for two cases].

In patients with either bilateral renal malignancies or with carcinoma occurring in a solitary kidney, the principle of en bloc removal of the tumor-bearing kidney cannot be applied. Recently we have performed surgical enucleation in two cases of asynchronous bilateral renal cell carcinoma. Case 1. A 60-year-old woman was hospitalized with diagnosis of left renal tumor 10 years tumor 10 years after right nephrectomy for renal cell carcinoma. The tumor was enucleated while occluding the renal vessels. Pathological examination revealed that the tumor (a nodule of 35 g) was renal cell carcinoma of grade I and perfectly covered by pseudocapsule. Hemodialysis was not required. The patient has been well for more than 11 months postoperatively and Ccr is 65 ml/min. Case 2. A 62-year-old man with slight elevation of serum GOT and GPT level was examined by CT, which revealed a space occupying lesion in the left kidney. He had undergone nephrectomy for renal cell carcinoma of right kidney 11 years ago. Three nodules of 56 g, 6 g and 3 g were removed by in situ enucleation. They were renal cell carcinoma of grade II and there was no malignant penetration of the pseudocapsule pathologically. After surgery hemodialysis was required 10 times for 21 days. Renal function has been refined gradually and the patient is well with 47.3 ml/min of Ccr at 4 months postoperatively. Before this report of 2 cases there were 22 cases of asynchronous bilateral renal cell carcinoma in Japanese literature.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Renal Cell↗