Biomedical subjects

K Murata

Publications and source records attributed to K Murata.

At least 325 records · Page 18Linked to original sources

PubMed1996

Rat primary T cells expressing HTLV-I tax gene transduced by a retroviral vector: in vitro and in vivo characterization.

We prepared a recombinant retroviral vector expressing the human T-lymphotropic virus type-I tax gene. Infection of WKA/H rat splenocytes yielded T-cell lines which proliferated continuously in media supplemented with exogenous interleukin-2 (IL-2) after the control cells ceased to grow. The phenotype of these cells closely resembled that of typical adult T-cell leukemia cells and tax-immortalized human T cells; i.e., positive for CD3, CD4 and IL-2 receptor alpha-chain. Chromosomal analysis revealed that about 10% of the tax-transduced T cells had several chromosomal abnormalities. We also performed in vivo characterization of tax-transduced splenocytes by injecting them into newborn syngeneic rats soon after in vitro infection. Maintenance of the injected tax-transduced cell population and in vivo expression of the tax gene was confirmed in the splenocytes of the injected rats by polymerase chain reaction. However, development of obvious disease was not observed in these rats for up to 18 months after inoculation. These results indicate that tax is capable of immortalizing rat mature CD4+ T cells in vitro but may be insufficient for full transformation of these cells in vivo. Our in vivo system using retrovirally tax-transduced rat T cells could facilitate investigation of the additional genetic events that cooperatively transform T cells transduced with tax gene.

Animals↗

PubMed1996

Molecular cloning and identification of N-acyl-D-glucosamine 2-epimerase from porcine kidney as a renin-binding protein.

N-Acetylneuraminic acid (NeuAc) is an important molecule in biological recognition systems. NeuAc is known to be biosynthesized either from UDP-N-acetyl-D-glucosamine by an action of UDP-N-acetyl-D-glucosamine 2-epimerase or from N-acetyl-D-glucosamine by N-acyl-D-glucosamine 2-epimerase (GlcNAc 2-epimerase). However, the physiological function of the GlcNAc 2-epimerase in NeuAc biosynthesis has not been fully evaluated. To clarify the role of GlcNAc 2-epimerase in NeuAc biosynthesis, the enzyme and its gene were isolated from porcine kidney cortex. Escherichia coli cells transformed with the gene expressed the GlcNAc 2-epimerase having the same properties as those of the GlcNAc 2-epimerase from porcine kidney. Sequence analysis indicated that the gene was capable of synthesizing a 46.5-kDa protein (402 amino acids) with a conserved leucine zipper motif. Homology search for the cloned gene revealed that the GlcNAc 2-epimerase was identical with renin-binding protein (RnBP) in porcine kidney (Inoue, H., Fukui, K., Takahashi, S., and Miyake, Y.(1990) J. Biol. Chem. 265, 6556-6561) (identity: 99.6% in nucleotide sequence, 99.0% in amino acid sequence). That GlcNAc 2-epimerase is a RnBP was confirmed by its ability to bind porcine kidney renin and mask its protease activity. These findings provide unequivocal evidence that the enzyme GlcNAc 2-epimerase is a RnBP.

Amino Acid Sequence↗

PubMed1996

Pit structure on bacterial cell surface.

The yellow-pigmented bacterium isolated from a ditch was a gram negative rod with a G+C content of 63 mol%, and was classified in the genus Sphingomonas. Electron microscopy revealed that the bacterial cell surface was covered with many large plaits. When grown in a medium containing a polysaccharide as an essential nutrient, a pit of 0.02-0.1 micrometers in diameter was formed on the cell surface, and a thin section showed the rearrangement of the plaits and the presence of a region where the cell membrane sinks into the cytosol. The dependence of the pit formation on the presence of macromolecule may predict the existence of a direct uptake mechanism for macromolecules through a mouth-like pit, possibly in endocytosis fashion. The confirmation of the pit structure is the first such finding in the history of microbiology and may provide a new insight into the cell morphology and biochemistry of macromolecule transport in microbial cell system.

Alginates↗

PubMed1996

Semotiadil improves survival of rats with monocrotaline-induced pulmonary hypertension: comparison with diltiazem.

We compared the effects of semotiadil, a novel Ca2+ channel blocker, with those of diltiazem on survival and regression of right ventricular hypertrophy and media thickening of pulmonary arteries in a rat model of pulmonary hypertension. Pulmonary hypertension was induced by a single injection of monocrotaline (80 mg/kg). Four weeks later, after pulmonary hypertension was confirmed, oral administration of semotiadil (10, 30, or 100 mg/kg/day) or diltiazem (100 or 300 mg/kg/day) was initiated. The rats were observed for 3 weeks. Survival was significantly longer in the group that received semotiadil 100 mg/kg/day than in the groups treated with diltiazem 100 or 300 mg/kg/day. Media thickness and smooth muscle area in pulmonary arteries were significantly less in rats treated with semotiadil 100 mg/kg/day than in animals treated with diltiazem 100 mg/kg/day. The right ventricle to left ventricle mass ratio, right ventricular wall thickness, and right ventricular myocardial fiber diameter were equal in these two groups. Semotiadil 100 mg/kg/day improved the survival of rats, which responded with a significant regression of right ventricular hypertrophy and media thickening of pulmonary arteries in comparison with rats treated with diltiazem 100 or 300 mg/kg/day.

Animals↗

PubMed1996

A novel method for the assessment of autonomic neuropathy in type 2 diabetic patients: a comparative evaluation of 123I-MIBG myocardial scintigraphy and power spectral analysis of heart rate variability.

The correlation between the degree of sympathetic denervation measured through 123I-MIBG Myocardial Scintigraphy and Power Spectral Analysis of consecutive R-R records was investigated in order to evaluate their potential application for the assessment of myocardial autonomic neuropathy in patients with diabetes mellitus. This study comprised 42 patients with Type 2 diabetes. Low frequency (0.02-0.09 Hz) components of the power spectral density were measured as markers of sympathetic activity. The myocardial uptake of 123I-MIBG was measured by using the single photon emission computed tomography (SPECT) and the early and delayed images were recorded. Scoring from 0 to 3 of the 123I-MIBG uptake of various cardiac segments (7) was performed and the total uptake was calculated. The washout rate in the whole myocardium was determined. The values obtained in the group with diabetic autonomic neuropathy (DAN) without orthostatic hypotension (OH) were significantly lower as compared to those of the (DAN (-)) group in the delayed images. The washout rate of the OH (-) group was also significantly higher than the DAN (-) group. There was significant difference between the images and the washout rate of OH (+) and OH (-) groups. There was a significant correlation between Power Spectral Analysis and SPECT (early, delayed images, and washout rate). Of these, the delayed image showed the strongest correlation (r = 0.55, p < 0.01). Further, the QTc interval showed a significant inverse correlation with the delayed image (r = -0.44, p < 0.05). In conclusion, these results suggest that the cardiac 123I-MIBG scintigraphy could be a useful method for the assessment of the myocardial autonomic neuropathy in patients with diabetes mellitus.

3-Iodobenzylguanidine↗

PubMed1996

Assessment of autonomic neurotoxicity in occupational and environmental health as determined by ECG R-R interval variability: a review.

Measurement of heart rate variability (coefficient of variation of ECG R-R intervals, CVRR) provides a useful approach for the objective assessment of the autonomic nervous function. It is noninvasive and clinically practical, although it tends to be distorted by confounding factors such as age, alcohol, and tobacco. Specifically, two component coefficients of variation of the respiratory sinus arrhythmia (RSA) and Mayer wave-related sinus arrhythmia (MWSA) in the CVRR (i.e., C-CVRSA and C-CVMWSA), computed from component spectral powers by autoregressive spectral and component analyses, are expected to reflect parasympathetic and sympathetic functions, respectively. This article is intended to present an overview of research, utilizing the CVRR method including the C-CVRSA and C-CVMWSA, in occupational and environmental health. The available literature, addressing the impact of some chemicals and work-related factors on human autonomic nervous system, indicates that parasympathetic activity appears to be more vulnerable to these factors than does sympathetic activity. Since decreased cardiac vagal tone is associated with an increased risk of sudden cardiac death or coronary artery disease, attention should be directed to further discovery of hazardous factors in the environment and work place, which are likely to affect the autonomic nervous system.

Autonomic Nervous System↗

PubMed1996

Subclinical impairment in the median nerve across the carpal tunnel among female VDT operators.

Sensory nerve conduction velocities in the palm-to-finger (SCV-pf), wrist-to-finger (SCV-wf), wrist-to-palm (SCV-wp), and wrist-to-elbow (SCV-we) segments and the distribution of nerve conduction velocities in the right median nerve were determined among 27 female operators aged 19-37 and 19 healthy women (controls) aged 19-31 to estimate the prevalence of subclinical carpal tunnel syndrome (CTS). Also, the WF/PF ratio, dividing the SCV-wf by the SCV-pf, was calculated to assess abnormalities of nerve conduction within the carpal tunnel. The operators were engaged in data entry in front of a visual display terminal (VDT) for about 6 h/day, and their working duration was between 1 and 17 (mean 6) years. The SCV-wf, SCV-wp, and WF/PF ratio in the operators were significantly lower than those in the controls. The rate of persons with the WF/PF ratio of less than 90%, i.e., below normal limits in the 19 controls, was significantly higher in the operator group (37%) than in the control group (0%). The operators complained of more symptoms related to CTS than did the controls, but any symptoms were not associated with slowing of nerve conduction velocities in the operators. In the controls, the WF/PF ratio was not closely correlated with skin temperature or age despite the presence of significant relations between skin temperature and the SCV-wf, SCV-pf, and SCV-wp; the interpersonal variability of the WF/PF ratio was much smaller than that of all SCVs. In the light of the present and previous studies, the rate of VDT operators with subclinical CTS seems to be high, independent of its symptoms. Also, the WF/PF ratio will be a useful and reliable screening method for the early detection of CTS due to repetitive wrist and finger movements involved in work.

Adult↗

PubMed1996

Autosomal dominant cerebellar ataxias in the Kinki area of Japan.

The autosomal dominant cerebellar ataxias are a heterogeneous group of neurodegenerative disorders characterized by slowly progressive cerebellar ataxia. Recently, among the ataxias, spinocerebellar ataxia type 1 (SCA1), Machado-Joseph disease (MJD) and dentatorubral-pallidoluysian atrophy have been found to be caused by expansion of a CAG trinucleotide repeat in the coding region of the disease genes. We have analyzed the CAG repeats of 67 patients from 47 families with dominantly inherited ataxia who lived in the Kinki area of Japan. The following results were obtained. First, 31 patients from 22 families were found to be positive for the MJD repeat expansion, indicating that MJD is the most common dominantly inherited ataxia in the Kinki area of Japan. Second, no SCA1 repeat expansion was found among the families studied. This presents a striking contrast to the fact that there are many families with SCA1 in Hokkaido and the Tohoku area of Japan. These findings suggest geographic variation in autosomal dominant cerebellar ataxias in Japan.

Asian People↗

PubMed1996

Protein C activation in NIDDM patients.

Enhanced activation of the clotting system has been recently implicated in the pathogenesis of vascular complications in patients with diabetes mellitus. Abnormalities of the anticoagulant system may constitute a potential trigger factor for the haemostatic activation observed in diabetic subjects. The current study aimed to evaluate anticoagulant activity in diabetic patients by assessing the plasma levels of activated protein C-protein C inhibitor complex; and by measuring the anticoagulant response to exogenous thrombomodulin. This study comprised 61 patients (34 men, 27 women) with non-insulin-dependent diabetes mellitus (NIDDM) of whom 22 showed microalbuminuria and 39 normoalbuminuria. Data obtained in 31 non-obese and non-diabetic subjects were available for comparison. The plasma levels of fibrinogen (p < 0.02), prothrombin fragment 1 + 2 (p < 0.05), fibrin monomer (p < 0.0001), protein C antigen (p < 0.005), total protein S antigen (p < 0.02), soluble thrombomodulin (p < 0.005) and soluble E-selectin (p < 0.005) were significantly higher in diabetic patients than in healthy subjects. The plasma level of activated protein C-protein C inhibitor complex (7.4 +/- 3.8 vs 3.0 +/- 0.4 pmol/l) was significantly higher (p < 0.0001) and the anticoagulant response to exogenous thrombomodulin (23.4 +/- 2.6 vs 35.3 +/- 3.0 ng/ml) was markedly lower (p = 0.005) in all diabetic patients than in healthy subjects. Cases with microalbuminuria presented low plasma levels of activated protein C-protein C inhibitor complex (5.5 +/- 0.6 vs 8.6 +/- 0.7 pmol/l, p < 0.05) and significantly decreased values of the anticoagulant response to exogenous thrombomodulin (16.5 +/- 2.9 vs 23.4 +/- 2.6%, p = 0.03) as compared to those with normoalbuminuria. The present study suggests that the hyper-coagulable state in NIDDM is associated with an increased activation of protein C but with a poor plasma reactivity to the anticoagulant effect of thrombomodulin.

Adult↗

PubMed1996

Ovarian fibromatosis with minor sex cord elements.

Ovarian fibromatosis is very rare, and the one with focal proliferations of sex cord type elements is extraordinarily rare. A 31-year-old patient developed the bilateral ovarian enlargements and complained of lower abdominal pain, Pathology indicated that these tumors were ovarian fibromatosis with minor sex cord elements. Our two-step operation involved the first right salpingo-oophorectomy for histological examination and the subsequent enucleation of the left ovarian tumor alone. The patient conceived 10 months after operation.

Abdominal Pain↗

PubMed1996

Relationship of (CAG)nC configuration to repeat instability of the Machado-Joseph disease gene.

The mutation responsible for Machado-Joseph disease (MJD) has been identified as an expansion of a CAG trinucleotide repeat in a novel gene on chromosome 14q32.1. The CAG repeat tract is followed by C or G, and alleles are thereby divided into two types on the basis of molecular configuration, (CAG)nC and (CAG)nG. We have studied the relationship between the repeat length and the configuration in 38 patients from 28 Japanese families with MJD, and 31 unrelated normal Japanese subjects. The CAG repeat length in 100 normal alleles ranged from 13 to 37 repeats, while 38 MJD patients had one expanded allele with 64 to 84 repeats. Surprisingly, the expanded alleles had exclusively the (CAG)nC configuration, while both (CAG)nC and (CAG)nG were seen in normal alleles from MJD and control subjects. Furthermore, in normal alleles, the CAG repeat tract was significantly longer in (CAG)nC than in (CAG)nG. These findings suggest that the (CAG)nC configuration is related to repeat instability of the MJD gene.

Alleles↗

PubMed1996

Oral immunization with a model protein entrapped in microspheres prepared from derivatized alpha-amino acids.

A model antigen, ovalbumin (OVA), was encapsulated in microspheres prepared from derivatized alpha-amino acids and administered orally to mice. These microspheres are quickly and easily prepared, without the use of organic solvents, high temperatures, or complex purification techniques. Immunological responses included induction of OVA-specific antibodies in both sera (IgG) and in intestinal secretions (sIgA), as well as antigen-dependent proliferation of splenic CD4+ T cells following, in some cases, as little as a single oral priming dose containing 0.1 mg OVA. Oral administration of microspheres was also found to be effective as a secondary immunization following a subcutaneous prime with soluble antigen. In addition, the protective effect of co-encapsulation of cholera toxin, a mucosal adjuvant, was demonstrated in a whole virus model (infectious bursal disease in chickens). These results indicate that oral administration of antigen-loaded derivatized alpha-amino acid microspheres can induce local and systemic antibody production and/or stimulation of effector cells.

Administration, Oral↗

PubMed1996

Evaluation of solubilizing methods of the egg envelope of the fish, Oryzias latipes, and partial determination of amino acid sequence of its subunit protein, ZI-3.

The inner layer of most teleostean egg envelopes, especially those after hardening, is almost insoluble in ordinary solvent, and therefore the inner layer of only the unhardened egg envelope has been subjected to solubilization with some potent solvents. We comparatively evaluated the methods of solubilization of the inner layer of egg envelope of medaka, Oryzias latipes, with SDS, urea and guanidium chloride (GuHCI). Analysis of the solubilized samples by SDS-polyacrylamide gel electrophoresis, comparison of their amino acid compositions or peptide maps using high-performance liquid chromatography and partial determination of their amino acid sequences showed that SDS and GuHCI were appropriate for solubilization and characterization of the envelope. Urea solubilization resulted in some artificial modifications of lysine and/or cysteine residues of envelope proteins. Partial determination of amino acid sequence of a subunit, ZI-3, isolated from the SDS-or GuHCI-solubilized envelope strongly suggested the identity of the envelope subunit, ZI-3, and its precursor, L-SF.

Amino Acid Sequence↗

PubMed1996

Radioimmunoassay for imidapril, a new angiotensin-converting enzyme inhibitor, and imidaprilat, its active metabolite, in human plasma and urine.

A radioimmunoassay (RIA) was investigated for the determination of imidapril and its active metabolite, imidaprilat, in human plasma and urine. Imidapril is a new angiotensin-converting enzyme inhibitor and an oral prodrug of imidaprilat. Imidapril was determined after conversion to imidaprilat with esterase. Antiserum was raised in rabbits against the p-amino derivative of imidaprilat conjugated to bovine serum albumin. Radioligand was prepared by iodination (125I) of the p-hydroxybenzoylamino derivative of imidaprilat. Cross-reactivities of anti-imidaprilat antiserum for imidapril, its metabolites and several cardiovascular drugs were low. The calibration range was 0.1-100 ng ml-1 using a 100 microliters of human plasma of urine. Intra- and inter-day variations of imidaprilat assay in plasma were 2.0-7.9 and 4.1-6.2%, respectively, and intra- and inter-day variations of imidapril assay in plasma were 5.4-10.7 and 7.9-18.1%, respectively. The variations of the assay in urine were a little smaller than those in plasma. The recovery of imidaprilat and imidapril spiked in plasma or urine samples was approximately 100%. A good correlation between RIA and high-performance liquid chromatograpy was observed for both plasma and urine samples. Furthermore, this method was applied to the determination of imidaprilat and imidapril in human plasma and urine samples, for the evaluation of the pharmacokinetics of imidapril in humans. From the results, it was demonstrated that the developed RIA was useful for the determination of imidaprilat and imidapril in human plasma and urine, and was applicable to pharmacokinetic studies in humans.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1996

An objective evaluation method for facial mimic motion.

This technique was designed to establish a simple, objective evaluation system for facial paralysis through the use of a personal computer. A total of 24 marks were placed on the faces of subjects for the following procedures. Movements of the face were photographed with a video-camera and fed continuously into the computer. Ten frames per movement representing facial movement from rest to maximum movement were selected for analysis. By means of a digital image-processing technique, only the marks placed on the face were extracted, and the movement of these marks was quantitatively analyzed. A total of 44 healthy subjects with no history of facial paralysis were used as a normal control group. The patients with facial paralysis consisted of nine subjects with Bell's palsy and three with Ramsay Hunt syndrome. In the eye-closing motions, no significant differences were found between the sum of the movement distances on the left and right sides in each normal subject. However, the patients with facial paralysis showed distinct differences from those obtained in the normal subjects. The improvement process was also evaluated with a ratio of affected- and normal-side facial movements.

Blinking↗

PubMed1996

Steady-state pharmacokinetics and pharmacodynamics of imidaprilat, an active metabolite of imidapril, a new angiotensin-converting enzyme inhibitor in spontaneously hypertensive rats.

Imidapril, a new angiotensin-converting enzyme (ACE) inhibitor, was infused subcutaneously at the rates of 9, 30, 90, and 300 micrograms/rat/day for 4 weeks via an osmotic pump implanted under the skin in the back of male spontaneously hypertensive rats (SHRs). Plasma concentrations of imidaprilat as an active metabolite of imidapril, systolic blood pressure (SBP), and plasma ACE activity were determined periodically. These results were also compared with those of enalapril. The plasma concentrations of an active metabolite of both the imidapril and enalapril groups increased according to the doses and showed almost the same plasma concentrations at the same doses. Both groups significantly inhibited plasma ACE activity and reduced SBP, and these actions were maintained for 4 weeks. At the lowest dose studied (9 micrograms/rat/day), imidapril was more potent than enalapril in inhibiting plasma ACE (maximum 2.5-fold difference), but this difference was reduced at higher doses. In contrast, significant differences in SBP effects were observed only at the highest dose studied (300 micrograms/rat/day). Also, the imidapril group significantly decreased the relative heart weight at the rate of 300 micrograms/rat/day. Furthermore, good correlations between plasma imidaprilat concentration and plasma ACE activity or SBP were observed, suggesting that plasma concentration may be a useful marker of pharmacological effects. However, a poor relationship between plasma ACE activity and SBP for enalapril was observed, suggesting that this may not be an adequate marker of pharmacologic efficacy of ACE inhibitors in general. The clinical relevance of these findings is not known at present.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1996

Gender difference in the utilization and users' characteristics of community rehabilitation programs for cerebrovascular disease patients in Japan.

The purpose of this study was to see whether there was gender difference in the utilization of a community rehabilitation program for cerebrovascular disease (CVD) patients in Japan and to examine factors affecting this gender difference. For CVD patients who participated in 16 community rehabilitation programs in the Saitama prefecture (n = 190), we studied their clinical and functional status, socioeconomic conditions, the degree of family support, and their use of rehabilitation and transportation services. The general characteristics of the programs and the type of transportation services they offered were also surveyed. The female proportion of all the program participants was 34.2% and its proportion tended to be smaller when their ADL level was worse. However, such difference by gender lessened after the participants were stratified by the type of transportation services and by such conditions as being accompanied by a family member during transportation.

Activities of Daily Living↗

PubMed1996

Crystallization and preliminary X-ray diffraction studies of N-acyl-D-glucosamine 2-epimerase from porcine kidney.

N-Acyl-D-glucosamine 2-epimerase from porcine kidney, which was cloned and expressed in Escherichia coli, was crystallized by the vapor-diffusion method, using polyethylene glycol and ammonium acetate as precipitants. The crystals were resistant to X-ray radiation damage and diffracted to more than 2.0 A resolution. The diffraction pattern indicated that the crystals belong to the orthorhombic system, space group P2(1)2(1)2(1), with unit-cell dimensions of a = 78.1, b = 97.2, and c = 100.7 A. It is supposed that the asymmetric unit consists of two N-acyl-D-glucosamine 2-epimerase molecules. Collection of data on the native crystals indicated that they are suitable for X-ray structural analysis.

Animals↗