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Biomedical subjects

Y Nishikawa

Publications and source records attributed to Y Nishikawa.

At least 55 records · Page 3Linked to original sources
PubMed2000

HGF/SF-induced spreading of MDCK cells correlates with disappearance of barmotin/7H6, a tight junction-associated protein, from the cell membrane.

Changes in expression of the two tight junction-associated proteins, barmotin/7H6 and ZO-1, as well as the adherence junction-associated protein, E-cadherin, were followed during hepatocyte growth factor/scatter factor (HGF/SC)-induced migration process of MDCK cells. Modulation of the HGF/SF-induced migration process by staurosporine, an inhibitor of protein kinase C (PKC), was also examined. Cell migration induced by HGF/SF consisted of two distinct phases, initial cell spreading between 2 and 9 h after the start of treatment, and the scattering phase which started approximately 12 h after treatment. Both ZO-1 and E-cadherin were expressed at the cell-cell border of adherent cells in the scattering phase, whereas barmotin/7H6, a barrier function-related tight junction protein, was not seen during the early spreading phase. Confluent cultures of MDCK cells, which did not spread after HGF/SF treatment, were positive for barmotin/7H6 expression at cell-cell borders. Blocking PKC activation during HGF/SF treatment with staurosporine inhibited cell spreading, and the cells retained barmotin/7H6 expression until at 6 h after HGF/SF treatment. The results indicate that disappearance of the tight junction protein, barmotin/7H6, is closely associated with cell spreading, with both barmotin/7H6 expression and cell spreading seemingly being regulated by PKC-mediated signaling.

Animals↗
PubMed2000

Radical hysterectomy: An anatomic evaluation of parametrial dissection.

OBJECTIVES: This study was designed to demonstrate a reduction in the amount of blood loss for vesicouterine ligament dissection and to investigate the intrapelvic autonomic nerve pathway and its preservation by means of anatomic analysis. METHODS: The anchoring mechanism of the pelvic viscera to the pelvic wall was divided into a supporting system facing laterally and a suspensory system facing dorsoventrally. An operative procedure was designed in which both systems were separated and dissected independently. RESULTS: Between the two systems, an artificial space was developed, which required a new dissection method for the parametrium and revealed a new anatomic pathway for the ureter and autonomic nerve. The amount of blood loss (mean +/- SD) during dissection of the vesicouterine ligament was ultimately 260.1 +/- 114.8 ml. Postoperatively, the maximum capacity of the bladder was 393.9 +/- 40.4 ml, maximum detrusor pressure 6.3 +/- 4.1 cm H(2)O, mean compliance >10 ml/cm H(2)O, residual urine 23.8 +/- 9.4 ml, and maximum flow rate 25. +/- 8 2.2 ml/s, respectively. CONCLUSION: A new classification for the parametrium and its dissection method have been established. Development of this new operative procedure has also contributed to a decrease in blood loss and preservation of bladder function.

Blood Loss, Surgical↗
PubMed2000

Delivery of Neospora caninum surface protein, NcSRS2 (Nc-p43), to mouse using recombinant vaccinia virus.

In order to develop a vaccine against Neospora caninum in dogs and cattle, we constructed a recombinant vaccinia virus expressing the N. caninum surface protein, NcSRS2 (Nc-p43). Monoclonal antibodies to NcSRS2 and anti-N. caninum tachyzoite mouse serum recognized the NcSRS2 expressed by the recombinant vaccinia virus. In addition, recombinant NcSRS2 was transported to the cell surface. Mice infected with the recombinant virus predominantly produced IgG1 antibody (Ab) to N. caninum, rather than producing IgG2a Ab. Moreover, splenocytes from mice infected with the recombinant virus proliferated in the presence of the N. caninum antigen. Mice immunized with the recombinant virus gave rise to humoral and cellular immune responses to N. caninum tachyzoites. This study showed that a recombinant vaccinia virus expressing NcSRS2 might be useful for the production of a live vaccine against N. caninum infection.

Animals↗
PubMed2000

Immunization of dogs with a canine herpesvirus vector expressing Neospora caninum surface protein, NcSRS2.

In order to develop a vaccine against Neospora caninum in dogs, we constructed recombinant canine herpesvirus (CHV) expressing N. caninum surface protein, NcSRS2. Indirect immunofluorescence indicated that the antigenic structure of the recombinant NcSRS2 was similar to the authentic parasite protein. The dogs immunised with recombinant virus produced IgG antibody to N. caninum, and their sera recognised the parasite protein on Western blot. The dogs inoculated with recombinant virus showed no clinical symptoms and infectious CHV was not recovered from the dogs, suggesting that recombinant CHV expressing N. caninum proteins may lead to a vaccine against neosporosis in dogs.

Animals↗
PubMed2000

Monoclonal antibody inhibition of Neospora caninum tachyzoite invasion into host cells.

Monoclonal antibodies were produced against Neospora caninum tachyzoites to identify antigens which may play a role during invasion of host cells. Confocal laser microscopy showed that most antigens recognised by the mAb were located on the surface, but one mAb, 1A5, reacted to the apical end of the parasite. Some mAbs, which recognised 70, 42 and 36kDa parasite proteins, significantly inhibited the invasion of the parasite in vitro. The mAbs which recognised 42 and 36kDa parasite protein, reacted with Nc-p43 and Nc-p36 expressed by vaccinia virus and Escherichia coli, respectively. These results suggest that a 70kDa protein, Nc-p43 and Nc-p36 are involved in the invasion of the parasite into host cells.

Animals↗
PubMed2000

Markers of apoptosis and angiogenesis indicate that carcinomatous components play an important role in the malignant behavior of uterine carcinosarcoma.

Carcinosarcoma of the uterine body is a relatively uncommon neoplasm that contains carcinoma components (CCs) and sarcoma components (SCs). Which component is responsible for the aggressive biologic behavior of this tumor has been a matter of discussion. Recently, many studies have indicated that angiogenesis and apoptosis play an important role in the biologic behavior of tumors. The aim of this study was to clarify, through the exploration of angiogenesis and apoptosis, which compartment is more important for the biologic behavior of carcinosarcoma. Paraffin sections from 10 uterine carcinosarcomas were stained by using anti-CD34 monoclonal antibodies for quantifying tumor vascularization. DNA nick was labeled immunostained by using an Apop Tag in situ apoptosis detection kit for exploring apoptosis. In addition, immunohistochemical staining for Ki-67 labeling index (LI) was conducted for evaluating cell proliferation. Although there was no significant difference in Ki-67 LI between SCs and CCs (P =.06), the microvessel density (MVD) in CCs was significantly higher than in SCs (P =.003), and the apoptotic index (AI) was significantly higher in SCs than in CCs (P =.002). Accordingly, CCs may play an important role in aggressive biologic behavior in carcinosarcoma. HUM PATHOL 31:1448-1454.

Aged↗
PubMed2000

Cloning of the human cDNA which can complement the defect of the yeast mannosyltransferase I-deficient mutant alg 1.

The assembly of the lipid-linked oligosaccharide, Glc(3)Man(9)GlcNAc(2)-P-P-Dol, occurs on the rough ER membrane in an ordered stepwise manner. The process is highly conserved among eukaryotes. In order to isolate the human mannosyltransferase I (MT-I) gene involved in the process, we used the Saccharomyces cerevisiae MT-I gene ( ALG1 ), which has already been cloned. On searching the EST database with the amino acid sequence of the ALG1 gene product, we detected seven related human EST clones. A human fetal brain cDNA library was screened by PCR using gene-specific primers based on the EST nucleotide sequences and a 430 bp cDNA fragment was amplified. The cDNA library was rescreened with this 430 bp cDNA, and two cDNA clones (HR1-3 and HR1-4) were isolated and sequenced. On a homology search of the EST database with the nucleotide sequence of HR1-3, we detected a novel human EST clone, AA675921 (GenBank accession number). Based on the nucleotide sequences of AA675921 and HR1-4, we designed gene-specific PCR primers, which allowed to amplify a 1.8 kb cDNA from human fetal brain cDNA. This cDNA was cloned and shown to contain an ORF encoding a protein of 464 amino acids. We designated this ORF as Hmat-1. The amino acid sequence deduced from the Hmat-1 gene showed several highly conserved regions shared with the yeast and nematode MT-I sequences. Furthermore, this 1.8 kb cDNA successfully complemented the S. cerevisiae alg1-1 mutation, indicating that the Hmat-1 gene encodes the human MT-I and that the function of this enzyme was conserved between yeast and human.

Amino Acid Sequence↗
PubMed2000

Streptococcal M protein enhances TGF-beta production and increases surface IgA-positive B cells in vitro in IgA nephropathy.

BACKGROUND: High serum levels and enhanced in vitro production of IgA are observed in more than half of patients with IgA nephropathy (IgAN); and transforming forming growth factor-beta (TGF-beta) is certain IgA class switching factor. On the other hand, macroscopic haematuria appears frequently with upper respiratory infection as tonsillitis in IgAN. METHODS: We compared the lymphocytic response to in-vitro stimulation by group A streptococcal M proteins of apparent virulence factor between IgAN, non-proliferative glomerulonephritis (NPGN), and normal subjects. M proteins were extracted from group A streptococcal strain type 5 and type 12 determined serologically. RESULTS: M protein-induced proliferation of lymphocytes from IgAN was higher than in NPGN but not in healthy control subjects. Flow cytometric analysis indicated that stimulation by M protein extracts derived from type 5 streptococci (M5) increased surface IgA-positive B cells in IgAN, but did not activate the production of soluble IgA. We also showed that M5 induced significant increases in TGF-beta, in culture supernatants of lymphocytes from patients with IgAN. CONCLUSION: Our results suggest that Streptococcal infection may play an important role in the pathogenesis of IgAN by stimulating IgA production through TGF-beta synthesis.

Adult↗
PubMed2000

Morphological characterization of bicontinuous structures in polymer blends and microemulsions by the inverse-clipping method in the context of the clipped-random-wave model.

A method is proposed to determine the spectral function of the clipped-random-wave (CRW) model directly from scattering data. The spectral function f(k) (k is a wave number) gives the distribution of the magnitude of wave vectors of the sinusoidal waves that describes the essential features of the two-phase morphology. The proposed method involves "inverse clipping" of a correlation function to obtain f(k) and does not require any a priori assumptions for f(k). A critical test of the applicability of the inverse-clipping method was carried out by using three-component bicontinuous microemulsions. The method was then used to determine f(k) of the bicontinuous structure of a phase-separating polymer blend. f(k) for the polymer blend turned out to be a multipeaked function, while f(k) for the microemulsions exhibits a single broad maximum representing periodicity of the morphology. These results indicate the presence of the long-range regularity in the morphology of the polymer blend. Three-dimensional (3D) morphology corresponding to the scattering data of the polymer blend was generated using the CRW model together with the multipeaked f(k). Interface curvatures of the 3D morphology calculated from f(k) were measured and compared with those experimentally determined directly from the laser scanning confocal microscopy in the same blend.

Journal Article↗
PubMed2000

Relationship of genetic type of Shiga toxin to manifestation of bloody diarrhea due to enterohemorrhagic Escherichia coli serogroup O157 isolates in Osaka City, Japan.

One hundred sixty-nine strains of enterohemorrhagic Escherichia coli serogroup O157 were examined for the correlation between the genotype of their Shiga toxin genes (stx) and manifestation of bloody diarrhea (BD). It was shown that the strains carrying only stx2vha were probably less virulent and caused BD less frequently.

Adolescent↗
PubMed2000

Nitric oxide exerts feedback inhibition on EDHF-induced coronary arteriolar dilation in vivo.

We tested the hypothesis that nitric oxide (NO) inhibits endothelium-derived hyperpolarizing factor (EDHF)-induced vasodilation via a negative feedback pathway in the coronary microcirculation. Coronary microvascular diameters were measured using stroboscopic fluorescence microangiography. Bradykinin (BK)-induced dilation was mediated by EDHF, when NO and prostaglandin syntheses were inhibited, or by NO when EDHF and prostaglandin syntheses were blocked. Specifically, BK (20, 50, and 100 ng. kg(-1). min(-1) ic) caused dose-dependent vasodilation similarly before and after administration of N(G)-monomethyl-L-arginine (L-NMMA) (3 micromol/min ic for 10 min) and indomethacin (Indo, 10 mg/kg iv). The residual dilation to BK with L-NMMA and Indo was completely abolished by suffusion of miconazole or an isosmotic buffer containing high KCl (60 mM), suggesting that this arteriolar vasodilation is mediated by the cytochrome P-450 derivative EDHF. BK-induced dilation was reduced by 39% after inhibition of EDHF and prostaglandin synthesis, and dilation was further inhibited by combined blockade with L-NMMA to a 74% reduction in the response. This suggests an involvement for NO in the vasodilation. After dilation to BK was assessed with L-NMMA and Indo, sodium nitroprusside (SNP, 1-3 microgram. kg(-1). min(-1) ic), an exogenous NO donor, was administered in a dose to increase the diameter to the original control value. Dilation to BK was virtually abolished when administered concomitantly with SNP during L-NMMA and Indo (P < 0.01 vs. before SNP), suggesting that NO inhibits EDHF-induced dilation. SNP did not affect adenosine- or papaverine-induced arteriolar dilation in the presence of L-NMMA and Indo, demonstrating that the effect of SNP was not nonspecific. In conclusion, our data are the first in vivo evidence to suggest that NO inhibits the production and/or action of EDHF in the coronary microcirculation.

Animals↗
PubMed2000

Adenosine preconditions against endothelin-induced constriction of coronary arterioles.

Myocardial hypoperfusion is accompanied by concomitant increases in adenosine and endothelin-1 (ET-1) production, but the vasodilatory effect of adenosine prevails over that of ET-1. Therefore, we hypothesized that adenosine-induced or ischemic preconditioning reduces the vasoconstrictive effect of ET-1. Coronary arteriolar diameter in vivo was measured using fluorescence microangiography in anesthetized open-thorax dogs. ET-1 (5 ng. kg(-1). min(-1) administered intracoronary, n = 10) induced progressive constriction over 45 min [25 +/- 6% (SE)]. The constriction was blocked by preconditioning with adenosine (25 microgram. kg(-1). min(-1) administered intracoronary) for 20 min and 10 min of washout (n = 10) or attenuated by ischemic preconditioning (four 5-min periods of ischemia, 9 +/- 5% at 45 min). To investigate the receptor involved in this process, coronary arterioles (50-150 micrometer) were isolated and pressurized at 60 mmHg in vitro. The ET-1 dose-response curve (1 pM-5 nM) was rightward shifted after preconditioning with adenosine (1 microM) for 20 min and 10 min of washout (n = 11). Blockade of A(2) receptors [8-(3-chlorostyryl)caffeine, 1 microM, n = 9] but not A(1) receptors (8-cyclopentyl-1,3-dipropylxanthine, 100 nM, n = 7) prevented this shift. These results suggest that adenosine confers a vascular preconditioning effect, mediated via the A(2) receptor, against endothelin-induced constriction. This effect may offer a new protective function of adenosine in preventing excessive coronary constriction.

Adenosine↗
PubMed2000

Ontogeny of pig discrete Peyer's patches: distribution and morphometric analysis.

We investigated the development of lymphoid and non-lymphoid cells in discrete Peyer's patches (PP) of the pig using immuno-histology and image analysis. In newborn piglets discrete PP were mainly populated by CD2+, CD3+ T cells, and major histocompatibility complex class II+ cells, many of which were of macrophage and dendritic cell lineage. Four days after birth, cells were localized in defined regions: the follicle; the inter-follicular area and the dome region. Compartmentalization within the follicle started about 6 days after birth. The first signs of secondary follicles were seen from about 14 days. The pig discrete PP attained their mature structure at about 3 weeks after birth. Here we show that despite the demonstration at birth of the cell types that support antigen processing and presentation, PP did not fully differentiate morphologically until at least this time when antigen can be handled in an efficient manner.

Animals↗
PubMed2000

Chemical characteristics of dehydro-L-ascorbic acid.

Dehydro-L-ascorbic acid (DAA) exists mainly in its C2 hydrated bicyclic form (5) in an aqueous solution, and monocyclic DAA (3), which is the expected reaction product immediately after the oxidation of AA, has not been observed by NMR spectroscopy. The formation mechanism for 5 from 3 and the stability of 5 were examined by the semi-empirical molecular orbital method (MOPAC). It was indicated that the protonation reaction was the key step in the formation of 5, therefore, the formation of 5 is thought to be more difficult under physiological conditions which mostly involve in the neutral or slightly alkaline state. However, by NMR, it was confirmed that, even in a neutral or slightly alkaline state very close to physiological conditions, the predominant form of DAA existing in an aqueous solution immediately after the enzymatic oxidation of AA was confirmed to be 5, although the possible existence of other forms of DAA at very low concentrations could not be completely excluded.

Dehydroascorbic Acid↗
PubMed2000

Interconversion between dehydro-L-ascorbic acid and L-ascorbic acid.

L-Ascorbic acid (AA) plays an important role in biological systems as an electron donor. Erythorbic acid (EA) is the epimer of AA and has chemical characteristics very similar to those of AA. It is demonstrated in the present study by 1H-NMR that dehydro-L-ascorbic acid (DAA) was reduced by EA under neutral conditions but not acidic, and that dehydroerythorbic acid (DEA) was also reduced by AA under the same conditions. These reactions also occurred at a low concentration close to the concentration of AA in such biological tissue as the liver. Furthermore, the interconversion of DAA and AA at neutral pH and low concentration was also confirmed by radioluminography. These results suggest the interconversion between DAA and AA in vivo.

Ascorbic Acid↗
PubMed2000

Time-dependent changes of tissue erythorbic acid concentrations in guinea pigs.

The concentrations of erythorbic acid(ErA) and L-ascorbic acid(AsA) in the tissues of guinea pigs orally administered AsA or ErA were measured over the passage of time using high-performance liquid chromatography. Guinea pigs were each administered 5 mg AsA or 100 mg ErA, and killed at a specified time thereafter. The AsA concentrations in the tissues of AsA-administered guinea pigs and the ErA concentrations in the tissues of ErA-administered guinea pigs increased for 3 h after the respective administrations and decreased thereafter in both groups. The AsA concentration in the tissues of AsA-administered guinea pigs tended to be similar to the sum of AsA and ErA concentrations in the ErA-administered guinea pigs within 3 h after administration.

Adrenal Glands↗
PubMed2000

[A case of posttraumatic severe ventriculitis treated by intraventricular lavage].

A 44-year-old male was admitted in a state of semicoma, tonic convulsion and elevated body temperature nine days after sustaining head injury. He had severe nuchal rigidity. Computed tomography revealed dilation of ventricles and swelling of the brain parenchyma. We performed cerebrospinal fluid (CSF) drainage of both lateral ventricles immediately. The fluid drained from both ventricles was just like pus. We diagnosed the patient's condition as posttraumatic ventriculitis and meningitis. We performed intraventricular lavage (IL) which was our ventricular irrigating technique. IL was repeated until the 7th day postoperatively. The CSF data improved immediately. Continuous spinal drainage (CSD) also was used for CSF drainage from the 7th day postoperatively. The patient recovered without the need for CSF shunt. Some authors have reported the usefulness of continuous intraventricular irrigation (CIVI) for treatment of severe ventriculitis. However, their patients required CSF shunt surgeries. Such shunts are likely to become infected more frequently than routine shunting. Our IL was able to drain pus and inflammatory products in the ventricles before the formation of septations in the ventricles. We emphasize that IL in combination with CSD is able to bring about good results for patients with severe ventriculitis.

Adult↗