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Biomedical subjects

H Morikawa

Publications and source records attributed to H Morikawa.

At least 55 records · Page 3Linked to original sources
PubMed1999

Simultaneous separation of common mono- and divalent cations on silica gel modified with aluminium by non-suppressed ion chromatography with conductimetric detection and nitric acid-15-crown-5 as eluent.

The modification of silica gel with aluminium by a coating method was very effective for the preparation of silica-based stationary phases which acted as a cation exchanger under strongly acidic conditions. However, the separation of common mono- and divalent cations (Li+, Na+, NH4+, K+, Mg2+ and Ca2+) on an aluminium-adsorbing silica (Al-Silica) column was moderate by a conductimetric detection ion chromatography (IC) with strongly acidic eluents. Then, the addition of various crown ethers (12-crown-4, 15-crown-5 and 18-crown-6) in acidic eluent was carried out. As a result, it was found that 15-crown-5 was most effective for the improvement of peak resolution. Excellent separation of these cations was achieved in 20 min by elution with 2 mM nitric acid-2 mM 15-crown-5. The proposed IC was successfully applied to the determination of major cations in various natural waters.

Aluminum↗
PubMed1999

Simultaneous determination of NK-104 and its lactone in biological samples by column-switching high-performance liquid chromatography with ultraviolet detection.

A simple and sensitive column-switching HPLC method has been developed for the simultaneous determination of NK-104 (HMG-CoA reductase inhibitor) and its lactone in human and dog plasma. Plasma sample was extracted with methyl tert-butyl ether and then the extract was subjected to methylation with diazomethane to prevent the mutual conversion between NK-104 and its lactone. The extract was injected into the column-switching HPLC system. The calibration curves of NK-104 and NK-104 lactone were linear over the ranges 0.5 to 100 ng/ml for human plasma samples and 0.5 to 500 ng/ml for dog plasma, respectively. The intra-day and inter-day C.V. values of these analytes were less than 13.3%. The intra-day and inter-day accuracies of these analytes were between -14.0 and 6.5%. The proposed method has been applied to plasma samples obtained after oral administration of a single 2 mg dose of NK-104 to volunteers.

Animals↗
PubMed1999

Transient expression of the beta-glucuronidase gene in tissues of Arabidopsis thaliana by bombardment-mediated transformation.

Particle bombardment has proved to be useful for the transformation of plants. We have previously reported successful transient expression of the beta-glucuronidase (GUS) gene in cultured plant cells and tissues and the stable transformation of various plants using a pneumatic particle gun. In this chapter, we describe transient expression of the GUS gene in Arabidopsis thaliana leaves and roots using the pneumatic particle gun.

Arabidopsis↗
PubMed1999

Opioid potentiation of N-type Ca2+ channel currents via pertussis-toxin-sensitive G proteins in NG108-15 cells.

Opioids have both inhibitory and stimulatory effects on neurotransmitter release. While the inhibitory effect has been ascribed to presynaptic inhibition of Ca2+ channels, the cellular mechanism underlying the stimulatory effect is not clear. In order to address this issue, we analyzed the effects of [d-Ala2, d-Leu5]-enkephalin (DADLE) on whole-cell Ba2+ currents (IBa) through voltage-gated Ca2+ channels in NG108-15 neuroblastoma x glioma hybrid cells. Application of DADLE inhibited and washout of DADLE transiently potentiated IBa. Furthermore, potentiation of IBa was elicited even in the presence of DADLE, when inhibition was relieved by a large depolarizing prepulse. DADLE-induced potentiation, as well as inhibition, had both voltage-sensitive and -insensitive components and was abolished by treatment with ICI174864, a delta-opioid antagonist, pertussis toxin (PTX) and omega-conotoxin GVIA. Potentiation developed over @3 min and took 5-20 min to recover, whereas inhibition was complete within 30 s and recovered within 1 min. Although this potentiation should contribute to DADLE-induced desensitization of Ca2+ channel inhibition, it was not the sole mechanism for desensitization. We conclude that the delta-opioid receptor exerts a dual action on N-type Ca2+ channels via PTX-sensitive G proteins, i.e., rapid inhibition followed by slowly developing potentiation.

Barium↗
PubMed1999

Left gastric vein hemodynamics and variceal recurrence in patients undergoing prophylactic endoscopic ligation of high-risk esophageal varices.

BACKGROUND: Early recurrence of esophageal varices remains problematic after endoscopic variceal ligation. To evaluate the efficacy of prophylactic endoscopic ligation for esophageal varices at high risk for bleeding, the relationship between left gastric vein hemodynamics and variceal recurrence was investigated. METHODS: Thirty-five patients with cirrhosis underwent endoscopic variceal ligation. Angiography was performed in all patients before treatment and after eradication of varices to study left gastric vein hemodynamics. RESULTS: Before treatment, 12 patients had hepatopetal flow in the left gastric vein (type I), 17 had hepatofugal flow (type II), and 6 had hepatofugal flow with an extra-esophageal shunt (type III). In type I and III patients, the direction of blood flow in the left gastric vein did not change after eradication of varices. Type II patients showed bi-directional flow in the left gastric vein after treatment. Varices recurred in all but one type II patient and in one type I patient during follow-up (mean 36.7 months). The 2-year recurrence-free rate was higher in type I patients (p = 0.0001) and type III patients (p = 0.0002) than in type II patients. CONCLUSIONS: Prophylactic ligation seems to be a safe and useful procedure, especially in patients with type I or III hemodynamics in the left gastric vein before treatment.

Angiography, Digital Subtraction↗
PubMed1999

Overexpression of rck/p54, a DEAD box protein, in human colorectal tumours.

The RCK gene is a target of the t(11;14)(q23;q32) chromosomal translocation observed in human B-cell lymphoma, and the overexpression of its protein (rck/p54) by the translocation was shown to cause malignant transformation. The rck/p54 protein belongs to the DEAD box protein/RNA helicase family, which has a variety of functions such as translation initiation, pre-mRNA splicing and ribosome assembly. The expression of rck p54 in colorectal adenocarcinoma cells was examined by immunohistochemistry and Western blot analysis. The rck/p54 protein was found to be overexpressed in tumour tissues resected from 13 (50%) out of 26 cases of colorectal adenocarcinomas and two out of two (100%) cases of colonic severe dysplastic adenomas. In view of activities of rck/p54 determined in other tissue types, we suggest that rck/p54 may contribute to the cell proliferation and carcinogenesis at the translational level in the development of colorectal tumours.

Adenocarcinoma↗
PubMed1999

Short communication: emission of nitrous oxide (N2O) from transgenic tobacco expressing antisense NiR mRNA

The emission of N2 and N2O from intact transgenic tobacco (clone 271) expressing antisense nitrite reductase (NiR) mRNA, and wild-type plants grown aseptically, on NO3-, NO2- or NH4+ -containing medium was investigated. 15N contents of gas sampled from gas-sealed pots, in which the plants were grown on 15N-containing medium, were analyzed by gas chromato- graphy and mass spectrometry (GC-MS). No emission of N2 was detected in either of the gas samples from plant clone 271 or the wild-type grown on NO3--containing medium. N2O emission from clone 271 grown on NO3--containing medium was detected, but not from the wild-type plants. The N2O emission rate of clone 271 was 106 ng N2O mg-1 incorporated N week-1 and the N2O emission was inhibited by tungstate (a nitrate reductase inhibitor). No emission of N2O was found from clone 271 or wild-type plants grown on medium containing NH4+. Emission of N2O also was detected from clone 271 grown on NO2--containing medium and its emission rate increased with increasing NO2- levels in plants. We speculate that NO3- is reduced to NO2- and that a part of NO2- is metabolized to N2O in clone 271.

Journal Article↗
PubMed1999

Stimulation of DNA synthesis in trophoblasts and human umbilical vein endothelial cells by hepatocyte growth factor bound to extracellular matrix.

Hepatocyte growth factor (HGF) promotes the growth not only of hepatocytes but also of several other types of cells such as cytotrophoblasts and endothelial cells. Recent studies have revealed that HGF is trapped in the extracellular (ECM) matrix through heparan sulphate in vivo, thereby acting as a mitogen for hepatocytes in cooperation with heparan sulphate. In this study, we detected HGF protein in chorionic tissue and placental tissue extracts, and found that HGF and heparan sulphate were co-distributed in the endothelial basement membrane and trophoblast basement membrane on immunohistochemical examination. The rates of DNA synthesis in primary cultured cytotrophoblasts and human umbilical vein endothelial cells (HUVEC) cultured on HGF-bound Matrigeltrade mark were 6-8 times those of control cytotrophoblasts and HUVEC. When Matrigeltrade mark dishes were pretreated with heparinase and heparitinase prior to binding of HGF, stimulation of DNA synthesis was markedly decreased. A considerable decrease in stimulation of DNA synthesis was observed following washing of HGF-bound Matrigeltrade mark with 1 m acetic acid, 1 m NaCl and 0.1 per cent trypsin, but not following treatment with chondroitinase ABC. These observations suggest that HGF can be trapped in ECM in vivo, thereby acting as a mitogen for cytotrophoblasts and placental vein endothelial cells in cooperation with heparan sulphate.

Analysis of Variance↗
PubMed1999

Balloon-occluded retrograde transvenous obliteration of high risk gastric fundal varices.

OBJECTIVE: Balloon-occluded retrograde transvenous obliteration is an effective new method for treating gastric fundal varices, but subsequent occurrence of esophageal varices creates a problem. The relationship between portal hemodynamics and the occurrence of esophageal varices after prophylactic balloon-occluded retrograde transvenous obliteration was investigated. METHODS: Ten cirrhotic patients considered to have high risk gastric fundal varices underwent angiography. Six patients showed a communication between blood flow in gastric wall vessels and that in the gastrorenal shunt (type I), whereas the others (type II) did not. Depending on the flow direction in the left gastric vein, the two groups were further divided into hepatopetal (a) and hepatofugal (b) subgroups. The therapeutic effect on portal hemodynamics and the relationship between pretreatment portal hemodynamics and posttreatment occurrence of esophageal varices were investigated. RESULTS: Fundal varices disappeared endoscopically in all 10 patients and the gastrorenal shunt was also occluded after the procedure. No patient showed worsening of liver function or systemic complications during follow-up. The increase in portal blood flow was more significant in type Ib patients than in the others. Esophageal varices occurred in all type I patients, and as to those in type Ib, high risk varices developed within 6 months after treatment. On the other hand, esophageal varices did not occur in type II patients. CONCLUSIONS: This procedure was effective for treating gastric fundal varices. However, type Ib patients are likely to develop high risk esophageal varices after occlusion of the gastrorenal shunt.

Adult↗
PubMed1999

Increased T-helper-1-type immunity and decreased T-helper-2-type immunity in patients with preeclampsia.

PROBLEM: To examine whether preeclampsia involves type-1 T-helper (TH1) immune hyperactivity. METHOD OF STUDY: Expression of HLA-DR, a cell-surface marker of activation, was analyzed on CD3+, CD4+, and CD8+ T cells in 15 preeclamptic patients and 15 normal pregnant women using flow cytometry. Additionally, peripheral blood mononuclear cells from preeclamptic patients and normal pregnant women were cultured with or without phytohemagglutinin (PHA) stimulation, and interleukin (IL)-2, IL-4, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha concentrations were determined in the supernatant by immunoassays. RESULTS: HLA-DR antigen was expressed more strongly on CD3+ T cells in preeclamptic patients than in normal subjects. In preeclampsia, HLA-DR was expressed more strongly in CD8+ T cells than in CD4- T cells. More TNF-alpha, IL-2, and IFN-gamma were produced by unstimulated and stimulated cultured peripheral blood mononuclear cells from preeclampsia patients than by those from normal subjects. TNF-alpha/IL-4, IL-2/IL-4, and IFN-gamma/IL-4 ratios were higher in preeclamptic patients than in the normal group. Significant positive correlations were observed between mean blood pressure and concentrations of the Th-1 type cytokines IL-2, IFN-gamma, and TNF-alpha. CONCLUSION: Up-regulation of Th1 responses and down-regulation of Th2 responses occur in preeclampsia.

Adult↗
PubMed1999

[Antioxidative effects of fluvastatin, and its major metabolites].

Fluvastatin (FV) is a highly potent inhibitor of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase. Recently, its antioxidant effect caused by inhibiting the formation of low density lipoproteins (LDL) in vitro has been reported. In this study, we reported the antioxidant effects of FV and its major metabolites in human (M-2, M-3, M-4, M-5, and M-7) on lipid peroxidation using rat liver microsomes. The extent of NADPH-induced microsomal (Ms) lipid peroxidation was determined by the thiobarbituric acid (TBA) assay. The antioxidant effect of each compound was shown as the percentage of inhibition on the formation of TBA reactive substances (TBARS) against the vehicle control. Probucol (PR), a potent antioxidant drug, was used as a reference control. The concentration of each compound in this experiment was set at 0.1 mM (final conc.). FV inhibited the formation of TBARS by 30 to 60% without depending on the used Ms concentrations (0.025-0.2 mg protein/ml). The antioxidant effects of M-2, M-3, and M-5 were comparable to that of FV at low Ms concentrations. At the highest Ms concentration, however, the antioxidant effects of these metabolites were considerably higher than that of FV. Inhibition of the formation of TBARS by M-4 or M-7 was approximately 30% of the control and independent of the used Ms concentrations. The antioxidant effect of PR was comparable to those of M-2, M-3, and M-5 in this study. Pravastatin (PV), a potent inhibitor of HMG-CoA reductase, reduced the formation of TBARS around 20% at 0.25 or 0.5 mg protein/ml of Ms concentrations. But the value of percentage of inhibition was around 5% at 0.1 or 0.2 mg protein/ml of Ms concentrations. In conclusion, the antioxidant effects of FV, M-2, M-3, and M-5 were found to be comparable to that of PR.

Animals↗
PubMed1999

Glomerular hypertrophy in preeclamptic patients with focal segmental glomerulosclerosis. A morphometric analysis.

BACKGROUND: Focal segmental glomerulosclerotic lesion (FSGS lesion) is frequently observed in preeclamptic patients with nephrotic syndrome. PATIENTS AND METHODS: We performed a morphometric analysis of renal biopsies from 20 patients with severe preeclampsia to evaluate the pathogenetic role of glomerular hypertrophy in preeclamptic nephropathy associated with FSGS lesion. We also analyzed biopsies obtained from 6 preeclamptic patients without FSGS lesion and 10 patients with isolated hematuria. Nonsclerotic glomeruli were examined. RESULTS: The mean glomerular tuft area (GTA), the whole glomerular area (WGA), and the extracellular matrix area (EMA) were significantly and negatively correlated with the postpartum day at biopsy in preeclamptic patients with FSGS lesion who underwent renal biopsy within 40 days after delivery. The mean GTA, WGA, EMA and number of mesangial cells (MN) were significantly increased in preeclamptic patients with FSGS lesion compared with patients with isolated hematuria and compared with those without FSGS lesion when the biopsy time was matched between patients with and without FSGS lesion. The GTA and WGA were not different between preeclamptic patients without FSGS lesion and patients with isolated hematuria. CONCLUSION: These results support the assumption that glomerular hypertrophy that develops during severe toxemic pregnancy plays an important role in the pathogenesis of FSGS lesion and is reversible about 40 days after delivery.

Adolescent↗
PubMed1999

[Collection of umbilical cord blood to separate the peripheral blood stem cells during the third stage of labor].

In order to collect the umbilical cord blood for the separation of peripheral blood stem cells, obstetrician have to get the document of informed consent from the pregnant women for the umbilical cord blood donation during pregnancy. After the fetal delivery, umbilical cord blood is easier collected from the umbilical vein of the placenta in utero than that of the delivered placenta. After the sterilization of umbilical cord, the special bag attached with tube and needle is more useful to collect the blood disinfectively and abundantly than the syringe. Blood stem cells should be separated as soon as possible after collection, but umbilical blood may be stored in the refrigerator until 24 hours after the collection, if the immediate separation is impossible. There is the positive correlation between the collected blood volume or the preserved hours until the separating management and the separated stem cells. Hearing on the health of the child should be followed until 6 months after delivery.

Cell Separation↗
PubMed1998

Structures of transgene loci in transgenic Arabidopsis plants obtained by particle bombardment: junction regions can bind to nuclear matrices.

To clarify the molecular structure of the integration sites of transgenes, we used particle bombardment to examine the DNA sequences of transgene loci. Three transgenic Arabidopsis lines gave a single Southern hybridization band with a selectable gene as the probe. Junction regions flanked by the transgenes were cloned by the inverse polymerase chain reaction method, and the characteristics of the DNA sequences of the 10 junction regions were investigated. All but two of these were AT-rich sequences bearing motifs characteristic of a scaffold/matrix-attachment region (S/MAR). Calculations showed that seven of them should have a propensity for curvature. An assay of in-vitro binding to tobacco nuclear matrices showed that all the junction regions bound to nuclear matrices and that the two input DNAs did not bind. The 12 chromosome/transgene (CT) junctions in these three transgene loci were investigated. Cleavage sites for topoisomerase I were found at 10 of the 12, near the junction point. The other two junctions had sites within 6bp of the junction point. The sequence near one terminal of the transgene in the transgene loci was compared with that near the other terminal. Short, direct repeats consisting of 4-6bp were present within 10bp of the junction points in the sequence. We speculate that the transgene introduced by particle bombardment is delivered on AT-rich S/MAR that has a propensity for curvature, and then a nucleotide near the short, direct repeat on the transgene is joined near the cleavage sites on the genome for topoisomerase I.

Arabidopsis↗
PubMed1998

Nociceptin receptor-mediated Ca2+ channel inhibition and its desensitization in NG108-15 cells.

It has been shown that the membrane of hybrid NG108-15 neuroblastoma x glioma cells contains a high-affinity binding site for nociceptin. In the present study, we first demonstrated the expression of nociceptin receptor mRNA in NG108-15 cells. Application of nociceptin to NG108-15 cells produced a concentration-dependent (EC50 = 29 nM) inhibition of Ca2+ channel currents in a pertussis toxin-sensitive fashion. This nociceptin-induced inhibition of Ca2+ channel currents was prevented in the presence of omega-conotoxin GVIA, a blocker of the N-type Ca2+ channel, and had both voltage-dependent and -independent components. Prolonged application of nociceptin elicited homologous desensitization of the inhibition with a time constant of 5.3 min. These results indicate that the nociceptin receptor is coupled to the N-type Ca2+ channel via pertussis toxin-sensitive G proteins in NG108-15 cells and that this coupling is associated with rapid and homologous desensitization.

Animals↗