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Biomedical subjects

Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 253 records · Page 14Linked to original sources
PubMed1999

Helper T cell determinant peptide contributes to induction of cellular immune responses by peptide vaccines against hepatitis C virus.

The capacity of novel subunit vaccines to generate cytotoxic T lymphocytes (CTLs) against hepatitis C virus (HCV) was assessed. BALB/c mice were immunized with peptides based on the CTL and helper T cell (Th) epitopes of the HCV core, with a mixture of CTL and Th peptides (CTL+Th) or with a conjugated Th-CTL peptide. Mice immunized with CTL, CTL+Th and Th-CTL peptides, but not those immunized with Th peptide, developed HCV core CTL epitope-specific effector cells. Cytotoxic activity induced by immunization with Th-CTL was much higher than that induced by immunization with CTL+Th or CTL alone. However, rapid and high cytotoxic activities against HCV core were not only detected after immunization with peptides containing the CTL epitope but also as a result of infection with recombinant vaccinia virus carrying the HCV core gene after immunization with the Th epitope alone. Immunization with peptides containing the Th epitope also elicited spleen cell proliferation. This study demonstrates the capacity of both Th and CTL activated peptide vaccines to elicit CD8+, MHC class I-restricted CTLs. The capacity of such CTLs to contribute towards a protective and/or pathogenic immune response against HCV can now be assessed in mouse models.

Amino Acid Sequence↗
PubMed1999

Development of restriction fragment-length polymorphism method to differentiate five subtypes of feline immunodeficiency virus.

Feline immunodeficiency virus (FIV) isolates have been classified into five subtypes (A to E) based on the sequences of the env variable V3 to V5 region. In this study, we sequenced a partial gag region of 4 and 3 isolates belonging to subtypes C and E, respectively. Phylogenetic analysis revealed that the branching pattern based on the region was similar to that based on the env V3 to V5 region. Here, we propose a protocol to differentiate five subtypes by polymerase chain reaction amplifying 329 bp within the region followed by restriction fragment-length polymorphism analysis using four restriction enzymes.

Animals↗
PubMed1999

Mechanically elicited nerve root discharge: mechanical irritation and waveform.

OBJECTIVE: Intraoperative monitoring is very important for protecting nerve roots during lumbar surgery for spinal degeneration. Our objective was to evaluate the correlation between the type of mechanical irritation and waveform by mechanically elicited EMGs during the surgery. METHOD: Mechanically elicited EMGs were recorded bilaterally on muscle groups innervated by the lumbar nerve roots in the area of surgery in 24 consecutive patients with lumbar spinal degenerative disease. RESULTS: It was confirmed that surgical irritation produced 3 types of waveforms as discharges from nerve roots; short, waning and continuous discharges. Each waveform was easily elicited mechanically and was sensitively related to the type and strength of mechanical stimulation. CONCLUSION: It was indicated that the mechanical irritation on the root could elicit the nerve root discharge with no post-operative nerve root deficit. It may be useful to monitor the mechanically elicited EMGs during the surgery for spinal degeneration.

Adult↗
PubMed1999

Cystic echinococcosis in a Jordanian patient: albendazole in a short-term immigrant.

With an ever increasing number of international travelers, physicians should be aware of the diseases that have rarely been encountered in their home countries. Cystic echinococcosis (CE) caused by Echinococcus granulosus is seldom seen in Japan despite frequent occurrence of the other type of echinococcosis, alveolar echinococcosis (AE) caused by E. multilocularis, in its northern parts. However, CE is prevalent in many parts of the world including the United Kingdom, Mediterranean basin, Middle East, South America, and Australia, and is supposed to be resurgent in several parts of the world. The disease is acquired by the oral ingestion of the eggs of E. granulosus passed into the feces of several definitive host animals carrying tapeworms, mostly dogs. These definitive hosts are infected by cannibalizing intermediate host animals including sheep and cattle whose livers and/or lungs are affected by cystic lesions that contain protoscoleces. In endemic areas the diagnosis of CE is not considered to be complicated; typical morphological features composed of cysts as revealed by ultrasonography and/or computerized tomography (CT) scan. The diagnosis is also aided by serological methods detecting serum antibodies. However, imaging procedures show a variety of features that could often lead to misdiagnosis as other diseases. Moreover, serological assays are sometimes difficult to interpret because of their incomplete sensitivities and specificities. Hence, a comprehensive understanding of a spectrum of imaging features and the application of serological methods with better sensitivities and specificities are indispensable. The mainstay of treatment of the disease is still surgical removal of cysts that has the potential to lead to a complete cure. Recently, the less invasive method PAIR (Puncture of cysts percutaneously, Aspiration of fluid, Introduction of protoscolicidal agent, and Reaspiration) was introduced with considerable success, and could be a promising alternative to surgery. Lastly, medical treatment with oral mebendazole or albendazole, especially the latter, can be beneficial not only as a adjunctive to surgery or PAIR, but as a sole treatment in cases in which invasive methods are not indicated. Here we report a Jordanian patient with CE whose diagnosis was substantiated by a novel immunoblot assay and who showed a rapid improvement during albendazole therapy.

Adult↗
PubMed1999

The Escherichia coli homologue of yeast RER2, a key enzyme of dolichol synthesis, is essential for carrier lipid formation in bacterial cell wall synthesis.

We found in the Escherichia coli genome sequence a homologue of RER2, a Saccharomyces cerevisiae gene required for proper localization of an endoplasmic reticulum protein, and designated it rth (RER2 homologue). The disruption of this gene was lethal for E. coli. To reveal its biological function, we isolated temperature-sensitive mutants of the rth gene. The mutant cells became swollen and burst at the nonpermissive temperature, indicating that their cell wall integrity was defective. Further analysis showed that the mutant cells were deficient in the activity of cis-prenyltransferase, namely, undecaprenyl diphosphate synthase, a key enzyme of the carrier lipid formation of peptidoglycan synthesis. The cellular level of undecaprenyl phosphate was in fact markedly decreased in the mutants. These results are consistent with the fact that the Rer2 homologue of Micrococcus luteus shows undecaprenyl diphosphate synthase activity (N. Shimizu, T. Koyama, and K. Ogura, J. Biol. Chem. 273:19476-19481, 1998) and demonstrate that E. coli Rth is indeed responsible for the maintenance of cell wall rigidity. Our work on the yeast rer2 mutants shows that they are defective in the activity of cis-prenyltransferase, namely, dehydrodolichyl diphosphate synthase, a key enzyme of dolichol synthesis. Taking these data together, we conclude that the RER2 gene family encodes cis-prenyltransferase, which plays an essential role in cell wall biosynthesis in bacteria and in dolichol synthesis in eukaryotic cells and has been well conserved during evolution.

Alkyl and Aryl Transferases↗
PubMed1999

Interspecies transmission of feline immunodeficiency virus from the domestic cat to the Tsushima cat (Felis bengalensis euptilura) in the wild.

Feline immunodeficiency virus (FIV) was isolated from a wild-caught Tsushima cat (Felis bengalensis euptilura), an endangered Japanese nondomestic subspecies of leopard cat (F. bengalensis). Phylogenetic analysis of the env gene sequences indicated that the FIV from the Tsushima cat belonged to a cluster of subtype D FIVs from domestic cats. FIVs from both the Tsushima cat and the domestic cat showed similar levels of replication and cytopathicity in lymphoid cell lines derived from these two species. The results indicated the occurrence of interspecies transmission of FIV from the domestic cat to the Tsushima cat in the wild.

Amino Acid Sequence↗
PubMed1999

Decavanadate inhibits the cell-free activation of neutrophil NADPH oxidase without affecting tyrosine phosphorylation.

NADPH oxidase was activated by arachidonate in a cell-free system consisting of membrane and cytosol fractions prepared from guinea pig neutrophils. Vanadate apparently inhibited the NADPH oxidase activity in the cell-free system (IC50=2 microM) without phosphotyrosine accumulation. The pH dependency and stability of the inhibitory effect observed for vanadate solution indicated that decavanadate, an isopolyanion of vanadate, was responsible for the inhibition. Pervanadate (vanadyl hydroperoxide) also inhibited the oxidase activity but at a higher concentration (IC50=0.2 mM). Decavanadate lowered the Vmax but did not affect the Km value of NADPH oxidase for NADPH. Decavanadate inhibited the activation process of NADPH oxidase but not the oxidase activity itself. Decavanadate-pretreatment of membrane and cytosol fractions irreversibly decreased the abilities of both fractions to activate NADPH oxidase in the cell-free system. Translocation of p47-phox, one of the cytosolic activation factors of NADPH oxidase, from cytosol to membrane, was little affected by decavanadate. These results suggest that decavanadate inhibits the activation of NADPH oxidase in the cell-free system without affecting the phosphotyrosine phosphatase, and that decavanadate can bind to both the membrane and cytosolic activation factors when they are in a dormant state, but not to the active oxidase complex.

Amino Acid Sequence↗
PubMed1999

Acute type A aortic dissection involving the left main trunk of the coronary artery--a report of two successful cases.

This report describes 2 cases of a type A acute aortic dissection combined with myocardial infarction caused by a retrograde dissection into the left main trunk of the coronary artery. Successful surgical treatments, including the replacement of the ascending aorta, aortic valve resuspension and coronary artery bypass grafting, were performed in both patients, and they recovered well from cardiogenic shock. However, left ventricular function of both patients remained depressed postoperatively, which limited their quality of life. Because no definite method for salvaging infarcted myocardium has yet been established, either more timely surgery or the preoperative placement of a perfusion catheter in the left main coronary artery is mandatory.

Acute Disease↗
PubMed1999

Radioprotective effects of sodium tungstate on hematopoietic injury by exposure to 60Co gamma-rays in Wistar rats.

Radioprotective effects of sodium tungstate (ST) on 60Co gamma-ray induced decrease in hematocrit value and in survival rate in Wistar strain male rats were examined. A long-term administration of ST (less than 150 mg/kg body weight/day) for 60-300 days had no significant effects on body and organs weights and survival days. The LD50/60 in 20 weeks old rats was 220 mg/kg body weight/day. Daily administration of 38, 75 or 150 mg from 7 days before and after irradiation to 60 days significantly mitigated the decrease in hematocrit values, especially at 23 days after irradiation (P < 0.05). The highest mitigation rate of the decrease in hematocrit value was observed in rats administered at a dose of 38 mg ST/day. Simultaneously, a dose of 38 mg ST/day inhibited lethal effect of 60Co gamma-rays significantly. The dose-reduction factor for survival of 38 mg ST administered rats was 1.14.

Animals↗
PubMed1999

Identification and sequence analysis of the Marek's disease virus serotype 2 gene homologous to the herpes simplex virus type 1 UL52 protein.

The gene of Marek's disease virus serotype 2 (MDV2) homologous to the UL52 gene of herpes simplex virus type 1 (HSV-1) was identified and characterized. The MDV2 UL52 homologous gene encodes 1,071 amino acids with a molecular weight of 118.7 kDa, which includes putative metal-binding site and overlapping region with the UL53 homologous gene. Although a putative polyadenylation signal sequence was found in the downstream of the MDV2 UL52 gene, a MDV2 UL52 DNA probe reacted only with the polycistronic 6.3 kb transcript, representing the UL52 and the downstream genes of UL53 and UL54. Transcriptional pattern of this region of MDV2 was somewhat different from corresponding regions of HSV-1 and infectious laryngotracheitis virus.

Amino Acid Sequence↗
PubMed1999

Characterization of feline CD56 molecule expressed on insect cells by the baculovirus expression system.

Recently we cloned 140 kDa form of feline CD56 cDNA. In this study, we expressed the feline CD56 molecule by the baculovirus expression system. We found that the molecule was expressed on the cell surface when examined by the indirect immunofluorescence assay using an anti-human CD56 monoclonal antibody. Immunoblotting analysis revealed that the molecular weight of the major expressed product was 140 kDa. Interestingly we found that the insect cells expressing the feline CD56 molecule aggregated, indicating that the expressed molecule mediates homophilic adhesion.

Animals↗
PubMed1999

Reactivity of intrarenal arteries to vasoconstrictor and vasorelaxant polypeptides in adult stroke-prone spontaneously hypertensive rats.

The reactivity of intrarenal arteries to vasoconstrictor and vasodilator polypeptides was examined in adult stroke-prone spontaneously hypertensive rats (SHRSP). The contraction response to endothelin-1 (ET-1) was greater in SHRSP than in age-matched Wistar-Kyoto rats (WKY), and so was the pD2 estimate (8.05+/-0.03 in SHRSP, and 7.73+/-0.06 in WKY; n=5, P < 0.05). The contraction response to, and the pD2 estimate of, vasopressin were comparable in SHRSP and WKY. Neuropeptide Y did not contract the intrarenal arteries. In norepinephrine-precontracted arteries with intact endothelium, substance P and neurokinin A did not relax the arteries of either SHRSP or WKY, while calcitonin gene-related peptide (CGRP) induced a profound relaxation response. Relaxation response to CGRP was significantly greater in SHRSP than in WKY. Atrial, brain, and C-type natriuretic peptides (ANP, BNP, CNP), vasoactive intestinal polypeptide (VIP), and peptide histidine isoleucine (PHI) all caused relaxation responses, with a greater extent of relaxation to ANP, BNP, and VIP and a less extent to CNP and PHI. However, there were no significant differences in these relaxation responses between SHRSP and WKY. The current results revealed the character of heterogeneity of rat intrarenal arteries in response to vasoconstrictor and vasodilator peptides, and showed an enhanced reactivity to ET-1 and to CGRP in SHRSP.

Animals↗
PubMed1999

Beta2-adrenergic receptor polymorphisms affect airway responsiveness to salbutamol in asthmatics.

We examined the beta2-adrenergic receptor (beta2AR) polymorphisms (Arg16-->Gly, Gln27-->Glu) and clinical status for 117 asthmatics. Airway responsiveness to methacholine and beta2-agonists was evaluated with Astograph. The atopic factors, pulmonary function test, and airway responsiveness to methacholine did not differ significantly among the different beta2AR genotypes. Asthmatics homozygous for Gly16 showed significantly lower airway responsiveness to inhaled salbutamol than those heterozygous for Arg/Gly16 or homozygous for Arg16. Asthmatics heterozygous for Gln/Glu27 had significantly later asthma onsets than those homozygous for Gln27. These results suggest that beta2AR polymorphisms play an important role in the airway responsiveness to inhaled beta2-agonist and the initial asthma onset.

Adolescent↗
PubMed1999

[Urinary disturbance in olivopontocerebellar atrophy (OPCA)--changes during the progression of the disease].

PURPOSE: Among spinocerebellar degeneration, syndromes categorized as multiple system atrophy (MSA) are commonly associated with neurogenic bladder, and urinary disturbances change with the disease progression. Accordingly, the changes in the urodynamic findings during the progression of the disease have been studied in the case of Olivopontocerebellar atrophy (OPCA) and OPCA type of MSA. METHODS: Urodynamic study (UDS) was performed more than twice in eight patients (5 males, 3 females, age 48-76, mean 55.0). The interval range between the first examination and follow up examination was 9-93 months (mean 42.4). UDS included cystogram, intravenous pyelography, residual urine volume, cystometry, urethral pressure profilometry, and external sphincter electromyography. RESULTS: The bladder was deformed in almost all patients with the progression of the disease, but the upper urinary tract was properly preserved. Residual urine volume tended to increase, and residual urine rate worsened significantly. The stable detrusor activity seemed to become overactive accompanied by detorusor hyperreflexia, and finally seemed to be acontractile. The normal sphincter activity seemed to become overactive accompanied by detrusor-sphincter dyssynergia, and finally complete relaxation could't be observed. CONCLUSION: These results suggest that urinary disturbance deteriorates together with other neuropathies as the disease progresses in OPCA. These patients should be continuously observed along with proper urinary management depending on the disease progression.

Aged↗
PubMed1999

Appearance of normal brain maturation on fluid-attenuated inversion-recovery (FLAIR) MR images.

BACKGROUND AND PURPOSE: Fluid-attenuated inversion-recovery (FLAIR) MR imaging is widely accepted for brain diagnoses, though to our knowledge no description of the MR FLAIR appearance of the normal infantile brain has been published. The purpose of this study was to investigate the appearance of normal infantile brain maturation on FLAIR MR images. METHODS: FLAIR images were obtained in 52 children between the ages of 1 day and 4 years who had clinically suspected brain disease but no neurologic abnormality or growth retardation. T1- and T2-weighted images were also obtained in all the children, and these images were compared with the FLAIR sequences for the appearance of brain maturation. A grading system for the differences in signal intensity between gray and white matter on FLAIR images was introduced to make detailed profiles of maturation in each brain region, including the posterior limb of the internal capsule, the cerebellar peduncle, the frontal deep white matter, the occipital deep white matter, and the centrum semiovale. These grades were plotted against patients' ages. RESULTS: On the FLAIR images, the myelinated white matter, including the cerebellar peduncle and the posterior limb of the internal capsule, showed high signal intensity relative to gray matter at birth. Thereafter, the white matter lost signal intensity with time and showed low signal intensity at 50 weeks and beyond. The unmyelinated white matter, including the frontal deep white matter, the occipital deep white matter, and the centrum semiovale, showed low signal intensity at birth. The white matter showed high signal intensity at 20 to 30 weeks, and low signal intensity again at 100 to 160 weeks and after. CONCLUSION: The dynamics of brain myelination can be accurately delineated and evaluated on FLAIR images without other spin-echo (SE) sequences. The FLAIR appearance of infantile white matter can be divided into two phases, reflecting development of the myelination process: the first phase is similar to that seen on SE T1-weighted images and the second phase is similar to that seen on SE T2-weighted images.

Brain↗