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Biomedical subjects

Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 649 records · Page 36Linked to original sources
PubMed1993

Phospholipase C activity in cerebrospinal fluid following subarachnoid hemorrhage related to brain damage.

Phosphoinositide-specific phospholipase C (PLC) activities were measured in CSF from patients after subarachnoid hemorrhage (SAH). Their PLC activities were significantly higher than those in control CSF. Moreover, there was an obvious correlation between the PLC activity in CSF collected on day 3 and the preoperative clinical grade. The PLC activity was also closely correlated with the level of neuron-specific enolase as a marker of brain damage. Furthermore, the PLC activities were partially purified from CSF of patients after SAH and were immunologically identified to be PLC beta, PLC gamma, and PLC delta. These results suggest that PLCs are released into the CSF from brain tissue in conjunction with the initial hemorrhage and that their activity may reflect the extent of brain damage.

Aneurysm, Ruptured↗
PubMed1993

Purification and processing of rat liver procathepsin B.

In order to characterize the intracellular processing event of lysosomal cathepsin B, the proenzyme was purified from the rat liver microsomal contents using a Con A-Sepharose column, a Sepharose-Gly-Phe-GlySc column, and an anti-cathepsin B IgG column. The purified proenzyme gave a single protein band of 39 kDa on SDS/polyacrylamide gel electrophoresis. The proenzyme showed no appreciable enzymatic activity. When the purified proenzyme was incubated with the cathepsin B-free tritosomal contents, prepared by treatment of the tritosomal contents with anti-cathepsin B IgG Sepharose, at pH 3.0, 30 degrees C, a remarkable increase of enzymatic activity was observed. Immunoblot analysis showed that the proenzyme was completely converted to the active intermediate form of 31 kDa after 1 h incubation. These processing and activation events were blocked in the presence of pepstatin. When the proenzyme was incubated with the cathepsins B- and D-free tritosomal contents, prepared by treatment of the cathepsin B-free tritosomal contents with anti-cathepsin D IgG Sepharose, the processing and activation did not occur. These results indicate that cathepsin D is involved in the processing and activation of procathepsin B in rat liver lysosome. In the NH2-terminal sequence analysis of the 31 kDa form, the terminal was assigned as proline (66th residue). Since the NH2-terminus of the mature single-chain form of cathepsin B (29 kDa) ends at leucine (80th residue), the NH2-terminus of the 31 kDa form is 14 amino acid residues longer than that of the single-chain form.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Difference in HLA-linked genetic background between mixed connective tissue disease and systemic lupus erythematosus.

We have typed 64 Japanese patients with mixed connective tissue disease (MCTD) and 53 Japanese patients with systemic lupus erythematosus (SLE) for HLA-DRB1, DRB3, DRB4, DRB5, DQA1, DQB1, and DPB1 genes by the HLA-DNA typing method using the PCR-SSOP technique. Frequencies of HLA-DRB1*0401, DRB1*0901, DRB4*0101, and DQA1*03 were increased and those of HLA-DRB1*0405 and DQB1*0401 were decreased in the patients with MCTD, while the frequencies of HLA-DRB1*1501, DRB5*0101, and DQB1*0602 were increased in the patients with SLE. The typing results suggest that susceptibility to MCTD is strongly associated with the HLA-DRB1*0401-DRB4*0101-DQA1*03-DQB1*0301 haplotype, and that to SLE is associated with the HLA-DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0602 haplotype. The observation that the MCTD-associated HLA alleles are distinct from the SLE-associated ones may support the clinical entity of MCTD different from SLE.

Alleles↗
PubMed1993

chpA and chpB, Escherichia coli chromosomal homologs of the pem locus responsible for stable maintenance of plasmid R100.

The pem locus is responsible for stable maintenance of plasmid R100 and consists of two genes, pemI and pemK. The pemK gene product is a growth inhibitor, while the pemI gene product is a suppressor of this inhibitory function. We found that the PemI amino acid sequence is homologous to two open reading frames from Escherichia coli called mazE and orf-83, which are located at 60 and 100 min on the chromosome, respectively. We cloned and sequenced these loci and found additional open reading frames, one downstream of each pemI homolog, both of which encode proteins homologous to PemK. The pem locus homolog at 60 min was named chpA and consists of two genes, chpAI and chpAK; the other, at 100 min, was named chpB and consists of two genes, chpBI and chpBK. The distal portion of chpBK was found to be adjacent to the ppa gene that encodes pyrophosphatase, whose map position had not been previously determined. We then demonstrated that the chpAK and chpBK genes encode growth inhibitors, while the chpAI and chpBI genes encode suppressors for the inhibitory function of the ChpAK and ChpBK proteins, respectively. These E. coli pem locus homologs may be involved in regulation of cell growth.

Amino Acid Sequence↗
PubMed1993

Neuropathological studies of the spinal cord in early stage HTLV-I-associated myelopathy (HAM).

Necropsy findings for a patient with HTLV-I-associated myelopathy (HAM) of 9 months clinical duration are reported. Loss of myelin sheaths and axons together with perivascular lymphocytic infiltration was seen in the lateral and posterior columns of the spinal cord from the cervical to the lumbar region where vacuolar changes caused by the splitting of myelin sheaths were prominent. Immunohistochemical analyses revealed CD8+ cytotoxic T cell infiltration predominated in the absence of HTLV-I core protein antigen bearing-cells in the brain and spinal cord. Myelin sheath damage and predominant CD8+ cytotoxic T cell infiltration are thought to be the main neuropathological findings in the spinal cord in early stage HAM.

Aged↗
PubMed1993

Assessment of sudomotor dysfunction in early Parkinson's disease.

We performed a quantitative sudomotor function test on 10 patients with early Parkinson's disease (PD) and 11 age-matched control subjects. Thermal warming increased the sweat rate in both PD and controls. There was no difference in sweat rate between the forearm and the thigh in either PD or controls. In PD, thyrotropin-releasing hormone (TRH) did not increase the sweat rate, whereas it did so in the controls. These results suggest that sudomotor dysfunction in early PD is minor but that there may be an impairment of TRH-induced sympathetic response in the early stages of PD.

Forearm↗
PubMed1993

Immunogenetic analysis of silicosis in Japan.

We previously reported that a gene in linkage disequilibrium with HLA-Bw54, DR4, and DRw53 might control the susceptibility to silicosis (K. Honda et al. 1988. N. Engl. J. Med. 319:1610). To further define the HLA-linked gene and other genetic factors for predisposition of silicosis, we determined for HLA-DQ and DP alleles using the polymerase chain reaction and sequence-specific oligonucleotide probes and made a restriction fragment length polymorphism (RFLP) analysis of the fourth component of complement (C4) genes, immunoglobulin lambda variable chain (IGLV) gene, and T-cell receptor alpha and beta genes in 46 Japanese patients with silicosis. The frequency of DQB1*0401 (relative risk [RR] = 2.2, P < 0.02) was increased and that of DQB1*0601 (RR = 0.36, P < 0.01) was decreased in the patients. RFLP analysis of C4 and IGLV genes showed significant association between silicosis and a specific RFLP pattern of C4A3-C4B5 allotype (RR = 2.3, P < 0.05) and that of IGLV 5.3 kb (RR = 0.33, P < 0.003). No other genetic markers showed significant association. Statistical analyses of the associated genetic markers revealed that the HLA-Bw54 was the allele that showed primary association with silicosis and the frequencies of the C4 and HLA-DQ alleles were suggested to be increased due to their linkage disequilibrium with the HLA-Bw54. We conclude that the major gene for silicosis may be mapped near the HLA-B locus.

Adolescent↗
PubMed1993

Roles of endothelin-1 and nitric oxide in the mechanism for ethanol-induced vasoconstriction in rat liver.

This study was designed to investigate the mechanism for ethanol-induced hepatic vasoconstriction in isolated perfused rat liver. Upon initiation of ethanol infusion into the portal vein at concentrations ranging from 25 to 100 mM, portal pressure began to increase in a concentration-dependent manner and reached maximal levels in 2-5 min (initial phase), followed by a gradual decrease over the period of ethanol infusion (escape phenomenon). Endothelin-1 antiserum significantly inhibited this ethanol-induced hepatic vasoconstriction by 45-80%. Cessation of infusion of endothelin-1 antiserum was followed by a subsequent increase in portal pressure. On the other hand, when a nitric oxide synthesis inhibitor, NG-monomethyl-L-arginine (L-NMMA), was infused into the portal vein simultaneously with ethanol, the initial phase of the response of portal pressure to ethanol was not altered and the peak values of portal pressure remained unchanged. However, after the peak increase in portal pressure, the rate of decrease was less than in the absence of L-NMMA. Thus, L-NMMA diminished the escape phenomenon and sustained the vasoconstriction. This study supports the hypothesis that two endothelium-derived vasoactive factors, endothelin-1 and nitric oxide, regulate hepatic vascular tone in the presence of ethanol.

Animals↗
PubMed1993

The embryologic development of the human anterior nasal aperture.

During the final period of embryogenesis, the nasal pit is clearly apparent in the Carnegie stage 15 embryo, and extends backwards into the oral cavity forming the nasal sac. In the stage 19 embryo of about 7 weeks, abundant epithelial proliferation into the lumen forms the nasal meatal plug. The complete recanalization of this meatal plug occurs in the 16-17 week fetus, and not in the 24th week of fetal life as is generally accepted in textbooks on human embryology. The findings of the present study of the embryology of the anterior nares can well explain the anomalies of the human anterior nares aperture.

Embryonic and Fetal Development↗
PubMed1993

Spin-trapping and chemiluminescence studies of neutrophils from a Holstein-Friesian calf with bovine leukocyte adhesion deficiency.

The ability of neutrophils from a Holstein-Friesian calf with bovine leukocyte adhesion deficiency (the proband with a genetic deficiency of the Mac-1 (CD11b/CD18) glycoprotein corresponding to the receptor of complement iC3b) to generate oxygen radicals was examined using electron spin resonance spectrometry (ESR) combined with a spin-trapping technique and luminol-dependent chemiluminescence spectrometry. When the neutrophils were stimulated with phorbol 12-myristate 13-acetate (PMA), an ESR spectrum confirming the generation of superoxide anions (O2-) was clearly observed in both healthy and diseased calves. However, when the neutrophils were stimulated by opsonized zymosan, appearance of the ESR spectrum was recognized in the healthy calves but not in the diseased calf. Similar results were obtained from chemiluminescence experiments.

Animals↗
PubMed1993

[Bone mineral loss in patients with chronic obstructive pulmonary disease].

Body weight loss is often observed in patients with chronic obstructive pulmonary disease (COPD). Bone mineral loss has also been reported in COPD, but the mechanisms are not well determined. To elucidate what factors influence on bone mineral content in COPD patients, we measured bone mineral content (BMC) by dual energy X-ray absorptiometry (DXA) (XR-26, Norland), pulmonary function, and ten minute walk distance (TMD) in Japanese elderly male patients with COPD. The subjects were 21 male patients with COPD (72.6 +/- 9.5 years) and 18 age-matched male normal individuals (66.5 +/- 9.5 years). COPD patients showed significantly (p < 0.05) lower BMC (1.82 +/- 0.33, 2.27 +/- 0.35 kg, respectively) compared with age-matched controls. BMC was significantly correlated with body weight and TMD (r = 0.71, r = 0.51, respectively). These results demonstrate that lower body weight and decreased exercise capacity account for the significantly lower bone mineral content of our COPD patients and that COPD patients with body weight loss may be at high risk for osteoporotic fracture.

Absorptiometry, Photon↗
PubMed1993

Embryological study of nasal cavity development in human embryos with reference to congenital nostril atresia.

An infant with congenital absence of the nostrils, incomplete prolabium, incomplete premaxilla, nasal cavity without septum, and cleft palate is presented. To clarify the embryological development of the nostril, serial sections of many embryos and fetuses of various stages were examined. Recanalization of the nostril, resulting from resorption of the temporary nasal epithelial plug, was observed in a 13- to 15-week fetus. Although textbooks of human embryology describe its occurrence in the 6th month or 24th week of fetal life. This finding suggests that the embryological cause of congenital nostril atresia, in the present case, may have been persistence of the plug.

Female↗
PubMed1993

Solution structures of Myb DNA-binding domain and its complex with DNA.

The DNA-binding domain of Myb consists of three imperfect tandem repeats, each of which contains three conserved tryptophans. The solution structure of the third repeat was established by NMR; it includes three helices maintained by a hydrophobic core formed by three tryptophans, together with two histidines, and the second and third helices form a helix-turn-helix-related motif. Here, we report the whole structure of the DNA-binding domain, as determined by NMR. Each of the first and second repeats resembles the third one in structure, retaining three helices. As a whole, the DNA-binding domain contains an entirely unique structure, a triple helix-turn-helix-related motif. To determine the role of each repeat in DNA-binding, a 16-mer DNA duplex that is specifically recognized by Myb was synthesized and then its complex with the DNA-binding domain has been investigated by 3D-NMR. The interaction mode between the whole DNA-binding domain and the duplex has shown that the third helix in each repeat likely locates in the majour groove of DNA. It is suggested that the Myb DNA-binding domain wraps around the DNA duplex by fitting the triply repeated helix-turn-helix-related motifs in the majour groove.

Base Sequence↗
PubMed1993

Structural features and properties of an extraordinarily stable hairpin-turn structure of d(GCGAAGC).

The extraordinarily stable hairpin-like structure formed by a short DNA fragment, d(GCGAAGC), has been studied by NMR spectroscopy and UV melting behaviour. The fragment is folded back between A4 and A5, and forms two terminal G-C base pairs and a non-Watson-Crick G-A base pair. All the nucleotides adopt C2'-endo sugar puckers. Both G1C2G3A4 and A5G6C7 moieties have characteristics of B-form geometry and within each moiety all the bases are involved in extensive base-base interactions. Distortion from B-form occurs in only the three torsion angles between A4 and A5 residues, which causes a sharp turn in the structure. There is no clear distinction between a stem and a loop region, as observed in usual hairpin structures, so that we classify it as a turn (hairpin-turn) structure. In addition to the thermal stability, this fragment is more stable towards the attack of some nucleases than other single-stranded as well as usual hairpin DNA fragments.

Hot Temperature↗