Biomedical subjects

H Kurata

Publications and source records attributed to H Kurata.

At least 127 records · Page 7Linked to original sources

PubMed1991

Study of mammalian selenocysteyl-tRNA synthesis with [75Se]HSe.

The mechanisms of the synthesis of mammalian selenocysteyl-(Scy)-tRNA were studied using [75SE]H2Se. H2Se was prepared from [75Se]selenite, glutathione, NADPH and glutathione reductase, and was purified by chromatography. It was confirmed that this H2Se was a Se donor in the reaction of the synthesis of Scy-tRNA. [75Se]Scy, liberated from aminoacyl-tRNA, was analyzed by TLC on silica gel an subsequent autoradiography. The activity of Scy-tRNA synthesis was found in the supernatant at 105,000 x g of the murine liver extract, but not in the precipitate. The supernatant was chromatographed on DEAE-cellulose, and the activity was eluted at a concentration of 0.17 M KCl. This position is at the front shoulder of the peak of seryl-tRNA synthetase which was eluted at 0.20 M KCl. Major serine tRNA(IGA) is not a substrate on which to synthesize Scy-tRNA, but natural opal suppressor serine tRNA is. On a chromatographic pattern of a Scy-tRNA preparation on Sephacryl S-200, the radioactivity of 75Se was eluted at the tRNA peak. This showed that Scy bound to tRNA. The active protein fraction from DEAE-cellulose did not contain tRNA kinase, therefore Scy-tRNA must be directly synthesized from seryl-tRNA, not through phosphoseryl-tRNA. This mechanism is similar to that seen in Escherichia coli [1991, J. Biol. Chem. 266, 6324].

Animals↗

PubMed1991

JC virus detection by in situ hybridization in brain tissue from elderly patients.

Brains from 10 patients aged 68 to 96 years at time of death were studied for JC viral DNA and common papovaviral capsid protein. In situ hybridization of JC viral DNA was performed by affinity cytochemistry using a biotinylated fragment of JC viral DNA. Immunohistochemistry was performed on brain tissue by the avidin DH-biotinylated horseradish peroxidase technique using polyclonal antibody raised against the papovaviral capsid protein. Viral protein and DNA were detected in 4 of 10 patients. JC virus may be present in the brains of aged patients more frequently than previously suspected.

Adult↗

PubMed1991

[Staphylococcus aureus sepsis in patients with hematological malignancies: increase in MRSA sepsis].

From January 1978 to August 1990, Staphylococcus aureus bacteremia (SAB) were identified in 31 patients with hematological malignancies at Jichi Medical School hospital. Mortality due to SAB was 48.4% (15/31). Of the variables analyzed, four factors were significantly associated with a poor prognosis; elderly age (p = 0.015), high granulocyte count (more than 500/microliters) (p = 0.015), presence of DIC (p = 0.011) and presence of pneumonia (p = 0.023). The incidence of methicillin-resistant SAB was 32.3% (10/31) and the first patient developed in 1985. Although not statistically significant, there was a trend of higher mortality for methicillin-resistant SAB (70%) than for methicillin-sensitive SAB (38.1%). Most strains of methicillin-resistant Staphylococcus aureus were sensitive to minocycline, chloramphenicol and vancomycin.

Adult↗

PubMed1990

Molecular cloning and sequence analysis of cDNA encoding the macrophage lectin specific for galactose and N-acetylgalactosamine.

The primary structure of the macrophage lectin specific for galactose and N-acetylgalactosamine (macrophage asialoglycoprotein-binding protein, M-ASGP-BP) has been deduced from its cDNA sequence. The M-ASGP-BP cDNA encoded a protein consisting of 306 amino acid residues with a molecular mass of 34,242 daltons. The sequence was highly homologous with that of the rat liver asialoglycoprotein receptor (rat hepatic lectin, RHL), particularly that of RHL-1 (the major form of RHL), throughout its whole length, and especially so in its putative membrane-spanning region and carbohydrate recognition domain. There were two N-glycosylation sites in M-ASGP-BP, the location of which were identical to those in RHL-1. However, M-ASGP-BP was characteristic in having a shorter cytoplasmic tail, and an inserted segment of 24 amino acids containing an Arg-Gly-Asp sequence between the membrane-spanning region and carbohydrate recognition domain.

Acetylgalactosamine↗

PubMed1990

Purification of inactivated photoresponsive nitrile hydratase.

Photoresponsive nitrile hydratase from Rhodococcus sp. N-771 was purified in its inactivated form. The enzyme had a molecular weight of approximately 60 kDa and consisted of 2 subunits each having molecular weight of 27.5 and 28 kDa. The enzyme also contained 2 iron atoms/enzyme as a cofactor. The enzyme was more stable in its inactivated form, rather than the activated during storage in the dark. The enzyme was most stable in the temperature region of 0-35 degrees C, and lost its activity above 40 degrees C. The enzyme was most stable in the pH region of 6-8. The optimum temperature and pH for the enzyme activity was 30 degrees C and 7.8, respectively. The enzyme showed wide substrate specificity, and most of the metal ions did not affect enzyme activity significantly. The absorption spectrum revealed the presence of some cofactor which changed form after photoirradiation.

Enzyme Activation↗

PubMed1990

Germ cell tumors of the thalamus and the basal ganglia.

Two cases of germ cell tumors (GCTs) of the basal ganglia are presented and 40 previously reported cases are reviewed. The incidence of GCTs of the basal ganglia and thalamus was estimated as less than 14% of all intracranial GCTs. All patients except for two (95%) were male, aged 7-19 years. The clinical course was usually slow. The major symptoms were hemiparesis, mental deterioration such as dementia or character change, precocious puberty, diabetes insipidus, oculomotor palsy, speech disturbance, and hemianopsia. Signs of intracranial hypertension did not occur until the late stages of the disease. The plain CT finding was characterized by an irregularly defined, slightly high-density area frequently accompanied by central low-density areas without significant mass effect. The tumors showed mild to moderate and nonhomogeneous contrast enhancement. An ipsilateral cerebral hemiatrophy was often found. MR images demonstrated the corresponding findings. GCTs of the basal ganglia had a high possibility of containing components other than germinoma such as choriocarcinoma, endodermal sinus tumor, and embryonal carcinoma. Thus, tumor markers in the serum, CSF, or cyst fluid were frequently positive. With recent refinement of microsurgical techniques as well as immunohistochemical study and measurements of tumor markers of serum, CSF, and cyst fluid, major resections of tumor, accurate pretreatment histologic diagnosis, and early determination of the specific types of this tumor appear to be readily possible. This is essential for effective treatment of patients not only with radiosensitive germinoma, but also those with radioinsensitive nongerminoma variants and a combination of them located in this region.

Adolescent↗

PubMed1990

Comparison of intranasal inoculation of influenza HA vaccine combined with cholera toxin B subunit with oral or parenteral vaccination.

The antibody responses to influenza virus A/PR/8/34 HA vaccine and protection against virus challenge in mice given the vaccine together with the B subunit of cholera toxin (CTB) intranasally were compared with those in mice given the vaccine with CTB perorally, intraperitoneally or subcutaneously. Intranasal vaccination induced remarkably higher levels of antiviral IgA antibodies in both respiratory washings and serum than did other routes of vaccination. The titres of antiviral IgG antibodies in respiratory washings and serum, and haemagglutination-inhibiting (HI) antibodies in serum, were similar after intranasal and parenteral vaccination. Oral vaccination, however, induced low levels of antiviral IgG antibodies but no detectable HI antibodies. Moreover, intranasal immunization elicited significantly higher titres of antiviral IgA antibodies in intestinal secretions in comparison with oral immunization. In contrast, parenteral immunization failed to induce these IgA antibodies. In virus challenge studies, a greater protective effect was seen after intranasal and intraperitoneal vaccination than after other routes of vaccination. These results suggest that intranasal inoculation of combined HA vaccine and CTB is superior to oral or parenteral inoculation in protecting mice. Furthermore, the intestinal antiviral IgA responses suggest that intranasal administration of CTB-combined vaccines could be effective not only against respiratory pathogens but also against enteropathogens.

Administration, Intranasal↗

PubMed1990

Diabetic strain (WBN/Kob) of rat characterized by endocrine-exocrine pancreatic impairment due to distinct fibrosis.

A spontaneously developed endocrine-exocrine pancreatic dysfunction was observed in the aged males of an inbred strain of Wistar rats, WBN/Kob. Nonobese male WBN/Kob rats developed glycosuria and hyperglycemia at around 9 months of age. Cumulative incidence of diabetes in male rats was 43% (33 of 76) at 12 months of age and reached 90% at the age of 21 months. In contrast, female rats did not become diabetic. Urinary excretion of amylase in WBN/Kob rats was significantly increased in comparison with control Wistar rats. Moreover, the exocrine pancreatic function test was impaired in WBN/Kob rats. Pathological examination of pancreata revealed infiltration of inflammatory cells, hemorrhage, deposition of hemosiderin, and fibrinous exudation around pancreatic ducts and blood vessels at 3 months of age. A gradual increase of fibrous tissue into the exocrine tissue and islets was observed with advancing age. The extremely enlarged interlobular lymph nodes were also observed. At the age of 12 months, the fibrous tissue replaced extensive areas of the pancreas and involved islets. The amylase content of pancreata in WBN/Kob rats was markedly decreased in comparison with that in Wistar rats at 12 months of age. Islets composed of few endocrine cells were detected. Immunohistochemical staining for insulin and glucagon showed a decreased number of not only B cells but also A cells. Moreover, both the pancreatic insulin and glucagon contents were markedly decreased in WBN/Kob rats in comparison with Wistar rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗

PubMed1990

Enhancement of DTH response by cholera toxin B subunit inoculated intranasally together with influenza HA vaccine.

The effects of B subunit of cholera toxin (CTB) on delayed-type hypersensitivity (DTH) response to influenza vaccine derived from influenza virus A/PR/8/34 (PR-8, HlNl) virus were investigated in B10 mice that were immunized intranasally with both influenza vaccine and CTB. The result showed that intranasal inoculation of this combination augmented DTH response to influenza vaccine, which reached its peak 6 days after inoculation, and also induced accelerated DTH response upon a second inoculation of influenza vaccine alone 4 weeks later, that the cross-reactive DTH response to PR-8 vaccine was elicited by the injection of the different influenza A-type virus vaccine into the footpad of the vaccinated mice, but was not by influenza B-type virus vaccine, that the DTH-mediating T cells were detected selectively in the lungs of mice that received the nasal inoculation of the vaccine and CTB together, but that subcutaneous inoculation of this combination failed to induce DTH-mediating T cells in the lungs. These results, together with the previous papers (Tamura et al, Vaccine 7: 257-262; 314-320, 1989), suggest that CTB could augment both humoral and DTH responses against influenza vaccine in the respiratory mucosal tract.

Adjuvants, Immunologic↗

PubMed1990

Reinvestigation of phosphorylation of tRNA in Escherichia coli.

This report shows the results of the reinvestigation of tRNA phosphorylation in E. coli. The phosphorylation did not occur on suppressor seryl-tRNA but occurred on other tRNA species. The activity of tRNA phosphorylation was found in E. coli extracts and partially purified. On DEAE-Sephadex A50 and PAGE gel, the phosphorylated-tRNA showed a pattern different from that the natural suppressor serine tRNA.

Chromatography, Ion Exchange↗

PubMed1990

[Clinical study on heterogeneity of chronic myelomonocytic leukemia].

We examined fourteen patients with chronic myelomonocytic leukemia (CMMoL) according to the following staging criteria at diagnosis; Group A: bone marrow (BM) blast less than 5% (eight cases), Group B; BM blast more than 5% and less than 30% (five cases), Group C; BM blast more than 30% (one case). Compared with Group A, Group B patients have much more peripheral blood leukocyte, granulocyte and monocyte counts, LDH level, and serum and urine lysozyme levels. Two of the five Group B cases transformed to acute leukemia (BC) within one and a half year, and other three patients died of infection and hemorrhage within a year. On the contrary, three of the eight Group A patients survived four years, and transformation to acute leukemia occurred in only one case after four years. Autopsy revealed multiple organ infiltration of monocytoid granulocytes on the patients with advanced stage and more bone marrow blasts. Two cases have coexistence of myeloproliferative disorders, one with essential thrombocythemia, and another with myelofibrosis, which, later, transformed to acute leukemia. And a Group C patient transformed to chronic phase with chemotherapy, and maintained the state for six years, but at the end stage, mature monocytes increased and pancytopenia developed. These findings indicate the heterogeneity of CMMoL in respect of the disease stage and the coexistence of other myeloproliferative disorders.

Aged↗

PubMed1990

[Report of a case which survived rupture in a hepatic artery mycotic aneurysm after aortic valve replacement].

A case in which rupture of a hepatic artery aneurysm occurred 4 months after aortic valve replacement because of aortic regurgitation due to infective endocarditis (IE) is reported. The patient was a 41-year-old male who underwent aortic valve replacement and closure of an abscess cavity of the Valsalva's sinus because of aortic regurgitation and an abscess of the Valsalva's sinus complicated with active IE. His postoperative course was good with no fever. Four months postoperatively, rupture of an aneurysm of the left intrahepatic artery occurred suddenly, and the patient's life was saved by resection of the lateral segment of the left lobe of the liver. Histologically, the wall structure of the aneurysm was not preserved, infiltration of neutrophils was seen in part of the wall, and a mycotic aneurysm of the left hepatic artery within the liver cause by IE was diagnosed. In Japan, only four cases, including the present one, of mycotic aneurysm of the hepatic artery have been reported in the literature examined, and this was the first case in which the patient's life as saved after a rupture. It is essential when observing the course of IE patients to bear in mind at all times that such a complication might occur.

Adult↗

PubMed1990

[Tricuspid annuloplasty and right ventricular function in mitral valve disease].

From 1985 to 1987, we examined relationship between the lesion of tricuspid valve and right ventricular function in 31 patients (male: 9, female: 22) with mitral valve disease. The median age at operation was 52 years (range 37-69 years). Group I consisted of 17 patients (MS: 10, MSR: 5, MR: 2) accompanied with tricuspid regurgitation (TR) and Group II 14 patients (MS: 12, MSR: 2) without TR. In all cases of Group I tricuspid annuloplasty (TAP) were performed correctly. De Vega methods were done in 12 cases and Carpentier rings were used in 5 cases. Cardiac catheterization was done before and after operation. And right ventricular volume was measured by right ventricular angiography. In both groups pulmonary capillary wedge pressure, pulmonary artery pressure and cardiac index were improved postoperatively. Pulmonary artery resistance (PAR) and total pulmonary resistance (TPR) in Group I were significantly higher before operation but there were no difference between two groups postoperatively. Right ventricular end-diastolic volume index (RVEDVI) and right ventricular end-systolic volume index (RVESVI) in Group I were significantly improved postoperatively, but in Group II these were within normal range both pre- and postoperatively. Preoperative PAR was correlated inversely with postoperative right ventricular ejection fraction (RVEF). It means that patients with severe pulmonary vascular lesion had postoperative lower right ventricular function. In both groups, RVESVI was in inverse correlation with RVEF pre- and postoperatively. In both groups, there was an inverse correlation between the per cent change of RVESVI and that of RVEF. This means that RVESVI influenced right ventricular pump function.

Adult↗

PubMed1990

[A case of chronic traumatic aneurysm of the descending thoracic aorta with the aberrant right subclavian artery].

A 59-year-old man had developed gradual prominence of the aortic knob in a chest X-ray film after a blunt chest trauma. Two and a half years after trauma, an angiogram revealed the aberrant right subclavian artery and a saccular aneurysm at the thoracic descending aorta just distal to it. It was treated with patch closure of the entrance of the aneurysm under a temporary bypass. Pathological findings were tearing off of a medial layer of the aorta. Postoperative course of this case was excellent. It must be noticed that the traumatic thoracic aortic aneurysm had a high possibility of rupture even in the chronic stage.

Aorta, Thoracic↗

PubMed1990

[Long survival of a patient presented with blastic crisis of chronic myelomonocytic leukemia].

A 77-year-old man was diagnosed as having acute myelomonocytic leukemia (M4) with increased ringed sideroblasts in the bone marrow (BM) in October, 1979. Complete remission was achieved and ringed sideroblasts disappeared after two courses of CMP (cytarabine, 6-mercaptopurine, prednisolone) therapy. Following remission, there was no increase of blasts during the course of the disease, but monocytosis and dysmyelopoiesis persisted for about seven years. The monocytosis was controlled by 6-mercaptopurine. In June, 1986, however, monocytosis in peripheral blood (PB) and BM developed again, and there was severe pancytopenia and reappearance of ringed sideroblasts without increase of blasts. The patient died of pneumonia on September, 1986. Postmortem examination revealed hypercellular marrow with a few blasts, leukemic cell infiltration into spleen, liver and lymph nodes, ad lung cancer. His clinical and hematological features after remission of acute leukemia accorded with those of CMMoL. The dysmyelopoiesis observed in this case in not induced by anti-leukemic agents, but originated from the same clone as the initial AMMoL, and his disease was thought to be CMMoL converted from blastic crisis to chronic phase.

Aged↗

PubMed1990

[Evaluation of the thromboexclusion technique for thoracic aortic aneurysms].

From 1981 to 1987 most of DeBakey III type dissecting aneurysms and a part of descending aortic aneurysms were treated by thromboexclusion technique. The effects of the operation by thromboexclusion technique on the patients were compared with those of the operation by temporary bypass technique. Blood loss during an operation was smaller and blood pressure during an operation was more stable in the thromboexclusion technique group, although the difference was not statistically significant. Furthermore, no paraplegia was observed in the thromboexclusion technique group. The respiratory support period was longer and the number of patients with postoperative myocardial injury was greater in the thromboexclusion technique group, although the difference was not statistically significant. Ten patients treated by thromboexclusion techniques were examined by computed tomography. In 7 out of 10 patients (70%), thrombosis occurred in the false lumen of dissecting aneurysm or in the aneurysmal lumen of descending aortic aneurysm. When only the patients without the leakage of blood into the aneurysm through the permanent aortic clamp were examined, thrombosis was observed in 100% of them. Even though the blood flow was reversed, thromboexclusion technique did not have a bad effect on renal function in the long-term. Postoperatively, however, progressive hypertrophy of the left ventricle was recognized, and furthermore, an injury to the aortic wall caused by permanent aortic clamp was observed at an autopsy. This suggests that further long-term follow-up of patients treated by thromboexclusion technique is necessary.

Aged↗

PubMed1990

[Myelodysplastic syndromes in the aged].

Seventy-five cases of myelodysplastic syndromes (MDS) in the aged (over 60 years) were analysed for hematological findings, immunological parameters and response to treatment in respect to prognostic significance. They were diagnosed according to the FAB classification, but patients with hypoplastic marrow were included if myelodysplasia was evident. Thirty-four percent of patients with primary acquired refractory anemia (PARA) or primary acquired sideroblastic anemia (PASA), and 36% of patients with RA with excess of blasts (RAEB) had hypoplastic bone marrow. The positive rates of antinuclear antibody in PARA or PASA, and of rheumatoid factor in PARA or PASA and in RAEB were higher than those in normal aged controls. Cellularity of bone marrow was inversely related to the length of survival. Among the patients with PARA or PASA, survival time was significantly longer in the group of hypoplastic bone marrow than in the group of hyper- or normo-plastic bone marrow, and in the group of good responder to treatment than in the group of poor responder and nontreated patients.

Aged↗

PubMed1989

Muscle fiber conduction velocity related to stimulation rate.

Muscle fiber conduction velocity in human biceps brachii muscle, produced by voluntary contraction and by contraction owing to microstimulation of a single motor unit, was measured with surface array electrodes. The conduction velocity of the fibers in the motor unit was calculated from the conduction time of the motor unit action potential along the electrode array and the electrode separation. With voluntary contraction, a conduction velocity of 4.25 +/- 0.43 m/sec (mean +/- S.D., n = 68) was obtained. In recording the surface EMG, the mean firing rate of the motor unit was 15.8 imp/sec (range 6-24 imp/sec). Significantly slower conduction velocity of 3.69 +/- 0.33 m/sec (mean +/- S.D., n = 56) was found after microstimulation (P less than 0.001). The higher the stimulation rate the higher was the conduction velocity. With increasing stimulus rates of 5, 10, 20 and 40 c/sec, the mean and S.D. of the conduction velocity were 3.74 +/- 0.33 m/sec (2.1% increase in the mean value to 1 c/sec stimulus rate), 4.16 +/- 0.37 m/sec (13.6%), 4.35 +/- 0.54 m/sec (18.8%) and 4.80 +/- 0.49 m/sec (31.1%), respectively. The firing rate for voluntary contraction was in the same range of the one obtained with 10-20 c/sec electrical stimulation, conduction velocity was the same in the two conditions. We conclude that measurement of muscle fiber conduction velocity should also be standardized with muscle fiber firing rate.

Adult↗