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Biomedical subjects

K Abe

Publications and source records attributed to K Abe.

At least 739 records · Page 41Linked to original sources
PubMed1998

Crystallization and preliminary X-ray diffraction studies of a rice cysteine proteinase inhibitor, Oryzacystatin-I.

Oryzacystatin-I from rice seeds was overexpressed in Escherichia coli, purified, and crystallized by the sitting-drop vapor diffusion method. Crystals obtained with 2-methyl-2,4-pentanediol as a precipitant exhibited space group I4122, with unit cell parameters of a = b = 100.0 A, c = 54.2 A, and diffracted up to 2.8 A resolution at 100 K. The crystals have one molecule per asymmetric unit.

Base Sequence↗
PubMed1998

Functional expression and enzymatic properties of two Sitophilus zeamais cysteine proteinases showing different autolytic processing profiles in vitro.

To characterize in more detail the cathepsin L-like cysteine proteinases from Sitophilus zeamais (SCPs) cloned in our previous study [Matsumoto et al. (1997) J. Biochem. 121, 464-476], we established a system for their functional expression and purification using a glutathione S-transferase (GST) fusion gene vector from Escherichia coli. The proenzyme forms of two representative SCPs, proSCPc1 and proSCPg3, were expressed as GST-fusion proteins and purified on a glutathione Sepharose column. GST-proSCPc1 undergoes autoproteolytic cleavage into the mature form efficiently at acidic pH, and exhibits significant proteolytic activity toward various substrates including hemoglobin and Z-Phe-Arg-MCA. The enzymatic characteristics of the activated form of SCPc1 are similar to those of mammalian cathepsin L, but its pH optimum for the hydrolysis of hemoglobin is significantly lower. The other proSCP, GST-proSCPg3, which has a shorter COOH-terminal domain than SCPc1, undergoes almost no autolytic processing and shows only very slight proteolytic activity, although the other enzymatic characteristics of GST-proSCPg3 are similar to those of GST-proSCPc1.

Amino Acid Sequence↗
PubMed1998

Identification of taste-tissue-specific cDNA clones from a subtraction cDNA library of rat circumvallate and foliate papillae.

To identify genes specifically expressed in taste tissues, we constructed a subtraction cDNA library of epithelium of rat circumvallate and foliate papillae and carried out differential screening of this library. Dot blot analysis showed 46 out of 88 clones obtained by this method to be expressed in the epithelium of papillae. The cDNA inserts in these clones were sequenced and analyzed for similarity to entries the GenBank database. About 54.3% of the clones were known sequences, including the sequences of ebnerin, cytokeratin 18, and Na+,K+-ATPase, that were shown by in situ hybridization to be expressed in the circumvallate papillae. About 41.3% of the papillae-specific clones had no significant similarity to known sequences and are candidates for novel taste bud-specific marker genes.

Animals↗
PubMed1998

Arterial oxygenation and shunt fraction during one-lung ventilation: a comparison of isoflurane and sevoflurane.

UNLABELLED: The aim of this study was to evaluate the effect of isoflurane and sevoflurane on oxygenation and shunt fraction during one-lung ventilation (OLV). Twenty patients undergoing lobectomy for lung cancer and scheduled for long-term OLV were enrolled in this study. Patients were allocated to treatment with either isoflurane or sevoflurane. Arterial oxygenation, shunt fraction, and hemodynamics were evaluated at the end of two-lung ventilation; 20 min after the initiation of OLV; 20 min after the application of 4-cm positive end-expiratory pressure (PEEP) to the dependent lung; 20 min after 8-cm PEEP; and 20 min after the conversion from OLV to two-lung ventilation. There was no significant difference between isoflurane and sevoflurane with regard to oxygenation, shunt fraction, or hemodynamics during OLV. PaO2 values after the application of 4-cm PEEP increased from 131.1 +/- 11.8 mm Hg to 190.6 +/- 22.9 mm Hg in the isoflurane group (P < 0.05) and from 127.2 +/- 14.3 mm Hg to 192.4 +/- 26.9 mm Hg in the sevoflurane group (P < 0.05). The selection of either isoflurane or sevoflurane for OLV was made without regard to arterial oxygenation and shunt fraction. PEEP application to the dependent lung is useful for improving oxygenation during OLV, but 8-cm PEEP had no added effect compared with 4-cm PEEP. IMPLICATIONS: We compared the effects of isoflurane and sevoflurane on oxygenation, hemodynamics, and shunt fraction during one-lung ventilation in 20 patients undergoing scheduled lobectomy for lung cancer. There was no significant difference between isoflurane and sevoflurane with regard to oxygenation, shunt fraction, and hemodynamics during one-lung ventilation. The application of 4-cm positive end-expiratory pressure increased the partial pressure of arterial oxygen during one-lung ventilation.

Aged↗
PubMed1998

Comparison of patient-controlled epidural analgesia with and without background infusion after gastrectomy.

UNLABELLED: To assess the analgesic efficacy and side effects of concurrent infusion in patient-controlled epidural analgesia (PCEA) after upper abdominal surgery, 40 patients undergoing elective gastrectomy under general anesthesia were allocated to two groups in this randomized, double-blind study: one received a 2.5-mL incremental bolus in a solution of 0.2% bupivacaine and 10 microg/mL fentanyl, and the other received the same bolus dose plus a 2.5-mL/h infusion of the same solution. The number of demands was smaller (P < 0.001) in the PCEA plus infusion group than in the PCEA alone group during the 48-h postoperative period. The average hourly fentanyl and bupivacaine doses were larger (P < 0.0001) in the PCEA plus infusion group than in the PCEA alone group. Visual analog scale pain scores on coughing in the PCEA plus infusion group were lower than in the PCEA alone group (P < 0.05). There was a greater incidence of pruritus in the PCEA plus infusion group (P < 0.05), but no serious side effects were observed in either group. In conclusion, a background infusion in PCEA with a mixture of fentanyl and bupivacaine decreases the incidence of postoperative pain and reduces the degree of pain associated with coughing without serious side effects after gastrectomy. IMPLICATIONS: A background infusion in patient-controlled epidural analgesia with a mixture of fentanyl and bupivacaine decreased the incidence of postoperative pain and reduced the degree of the pain associated with coughing without serious side effects in this randomized, double-blind study after gastrectomy.

Aged↗
PubMed1998

The effects of propofol, isoflurane, and sevoflurane on oxygenation and shunt fraction during one-lung ventilation.

UNLABELLED: Propofol's effect on hypoxic pulmonary vasoconstriction during one-lung ventilation (OLV) has not been determined. Twenty patients who had long-term OLV for esophageal surgery were allocated randomly to one of two study groups; one in which isoflurane administration preceded propofol, and another in which sevoflurane administration preceded propofol. Arterial and mixed venous blood samples and hemodynamics were measured as follows: before OLV, during OLV, OLV at 4 cm of positive end-expiratory pressure (PEEP), OLV after conversion from volatile anesthetics to propofol, OLV at 4 cm of PEEP, and after OLV. After the application of 4 cm of PEEP during propofol anesthesia, PaO2 increased significantly in both groups. The shunt fraction (Qs/Qt) increased significantly after the initiation of OLV in both groups and decreased significantly after the conversion from volatile anesthetics to propofol in both groups. Propofol can be used safely during OLV because PaO2 increased after the application of 4 cm of PEEP during propofol anesthesia, and Qs/Qt decreased significantly after the conversion from inhaled anesthetics to propofol anesthesia. IMPLICATIONS: During one-lung ventilation, the arterial partial pressure of oxygen values with propofol were greater than those with isoflurane and sevoflurane, and shunt fraction values with propofol were lower than those with both volatile anesthetics. Propofol improved oxygenation and shunt fraction during one-lung ventilation compared with volatile anesthetics.

Adult↗
PubMed1998

Reduction of ischemic damage by application of vascular endothelial growth factor in rat brain after transient ischemia.

Vascular endothelial growth factor (VEGF) is a secreted polypeptide and plays a pivotal role in angiogenesis in vivo. However, it also increases vascular permeability, and might exacerbate ischemic brain edema. The effect of this factor on the brain after transient ischemia was investigated in terms of infarct volume and edema formation, as well as cellular injury. After 90 minutes of transient middle cerebral artery occlusion, VEGF (1.0 ng/microL, 9 microL) was topically applied on the surface of the reperfused rat brain. A significant reduction of infarct volume was found in animals with VEGF application (P < 0.001) at 24 hours of reperfusion as compared with cases with vehicle treatment. Brain edema was significantly reduced in VEGF-treated animals (P = 0.01), and furthermore, extravasation of Evans blue was also decreased in those animals (P < 0.01). Terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling and immunohistochemical analysis for 70-kDa heat shock protein showed an amelioration of the stainings at 24 and 48 hours after reperfusion with VEGF treatment, which indicated reduction of neuronal damage. These results indicate that treatment with topical VEGF application significantly reduces ischemic brain damage, such as infarct volume, edema formation, and extravasation of Evans blue, and that the reductions were associated with that of neuronal injury.

Animals↗
PubMed1998

Inductions of 3-L-nitrotyrosine in motor neurons after transient spinal cord ischemia in rabbits.

The induction and distribution of 3-L-nitrotyrosine (NO2-Tyr) were examined with HPLC and immunohistochemistry in rabbit spinal cords after 15 minutes of transient ischemia until 7 days of the reperfusion. After the 15-minute ischemia, there was a significant decrease of neurologic scores in the ischemic group compared with the sham-operated control group at 7 days of reperfusion (P = 0.0017), and the majority of motor neurons was selectively lost at 7 days of reperfusion (P = 0.0039). NO2-Tyr was transiently induced at 8 hours of reperfusion in the ventral part of the spinal cord (0.47%+/-0.86%, NO2-Tyr/total tyrosine; P = 0.0021), but was not induced at any time point of reperfusion in the dorsal part of the spinal cord. Strong immunoreactivity for NO2-Tyr was selectively induced in large pyramidal motor neurons at 8 hours of reperfusion and was still weakly present until 7 days of reperfusion. (There may be a difference in sensitivity between the two techniques.) These results suggested that protein tyrosine nitration by nitric oxide plays a role in the selective motor neuron cell damage after transient spinal cord ischemia.

Animals↗
PubMed1998

Chronic effects of enalapril and amlodipine on cardiac remodeling in cardiomyopathic hamster hearts.

This study examined the effects of long-term treatments with the angiotensin-converting enzyme inhibitor, enalapril, and the calcium antagonist, amlodipine, on the morphologic changes, progressive left ventricular dysfunction, and gene expression of the ryanodine receptor (RyR) and phospholamban (PLN) in dilated cardiomyopathy. From the ages of 5 through 20 weeks, dilated cardiomyopathic hamsters, BIO53.58 (BIO), and control hamsters, F1b, orally received either enalapril or amlodipine. Cardiac function was assessed by echocardiography. At the age of 20 weeks, the collagen volume fractions were analyzed by the stereologic method. RyR and PLN messenger RNAs (mRNAs) were examined by Northern blot in the amlodipine group. In BIO, the reduction of left ventricular percentage of fractional shortening was attenuated in the enalapril group (p < 0.05) and amlodipine group (p < 0.001), and the increase in the collagen volume fraction and the loss of myocytes were suppressed in the amlodipine group compared with the untreated group. RyR mRNA level decreased in BIO (p < 0.01) compared with F1b, but PLN mRNA level was unchanged. RyR and PLN mRNA levels were unaffected by the treatment with amlodipine. Enalapril and amlodipine prevent progressive remodeling and reduce cardiac dysfunction in BIO. Amlodipine prevents fibrosis and cell death without modifying RyR and PLN mRNA levels in BIO.

Amlodipine↗
PubMed1998

Mitochondrial DNA deletion is a predisposing cause for sensorineural hearing loss.

Composed of a postmitotic stable tissue, the inner ear is a target organ for mitochondrial DNA (mtDNA) mutation. To determine whether mtDNA mutation is a predisposing factor in patients with sensorineural hearing loss (SNHL), the authors assessed the mtDNA4977 deletion from 60 patients with SNHL and 47 normal control subjects. All cases had no past history of ototoxic or noise exposure, middle ear disease, or other known etiological factors for SNHL. DNA specimens extracted from peripheral blood leukocytes were used for detection of mtDNA4977 deletion by polymerase chain reaction. Patients with SNHL had a significantly higher rate of the mtDNA4977 deletion than did controls (75% vs. 30%, P < 0.0001). The detection rate of mtDNA4977 deletion was significantly increased with the deterioration of the hearing threshold. Aging did not influence the detection rate of mtDNA4977 deletion in either the control or SNHL group. The authors have described high detection rates of the mtDNA4977 deletion in patients with idiopathic bilateral SNHL and propose that at least some of the advanced SNHL cases should be categorized as mitochondrial oxidative phosphorylation diseases. This inference would offer novel possibilities for treatment and prevention of SNHL including presbycusis.

Adult↗
PubMed1998

Recurrent brief episodes with psychotic features in adolescence: periodic psychosis of puberty revisited.

There are many reports of adolescents with periodic episodes, each followed by complete remission within 2 weeks; however, the nosology and long-term prognosis of such cases have not been elucidated. A prospective follow-up study on 11 cases (nine girls and two boys) who met predetermined criteria is reported. The first several episodes were found to meet ICD-10 symptomatic criteria for recurrent depressive disorder in all cases and, with the exception of two cases, showed psychotic features. The episodes were linked to one phase of the menstrual cycle in only two of six girls with regular menses. There were no recurrences while on lithium in eight of nine cases. Of nine patients followed up 5-14 years after the first onset, three had been well, three had become bipolar and three were still suffering from brief depressive episodes. Recurrent brief episodes in adolescence tend to show a near-monthly rhythm and psychotic features. Most appear to be manifestations of affective illness and may be treated and prevented as such.

Adolescent↗
PubMed1998

Further study of hepatitis C virus RNA detection in formalin-fixed, paraffin-embedded liver tissues by ligation-dependent polymerase chain reaction.

Ligation-dependent polymerase chain reaction (LD-PCR) is a novel, simple and sensitive PCR assay that could be useful for the molecular diagnosis of various viral infections. This assay uses two capture probes for RNA isolation and two hemiprobes for the subsequent PCR. To investigate its usefulness in the field of pathological diagnosis, further study of this new PCR technology to detect hepatitis C virus (HCV) RNA was carried out in formalin-fixed, paraffin-embedded (FFPE) liver tissues and the results compared with those obtained by the reverse transcription (RT)-PCR method. We analyzed routinely processed FFPE liver specimens of surgical origin from 13 anti-HCV-seropositive Japanese patients with hepatocellular carcinoma (HCC). As a result, HCV-RNA was detected in FFPE liver specimens in 12 of the tested patients (92.3%) by the LD-PCR method without the use of reverse transcription. In contrast, HCV-RNA was detectable in eight out of 13 cases (61.5%) by the RT-PCR method. These results indicated that LD-PCR was useful for HCV-RNA detection in routinely processed FFPE liver specimens.

Adult↗
PubMed1998

Characterization of t-butyl hydroperoxide toxicity in cultured rat cortical neurones and astrocytes.

The present study investigates the toxicity of t-butyl hydroperoxide (t-BuOOH) in cultured rat cortical neurones and astrocytes. Both neurones and astrocytes were destroyed by exposure to t-BuOOH in a time- and concentration-dependent manner. Astrocytes were more resistant to destruction by hydrogen peroxide (H2O2) than neurones, but there was no difference in susceptibility to t-BuOOH between neurones and astrocytes. The toxic effect of t-BuOOH was significantly blocked by antioxidants, propyl gallate and trolox, but not by superoxide dismutase nor by H2O2-scavengers, catalase and 4-nitrophenylglyoxylic acid. These results suggest that t-BuOOH toxicity is caused by oxidative stress unrelated to superoxide and H2O2. In addition, the toxic effect of t-BuOOH was attenuated by the presence of iron chelators, deferoxamine and N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine, indicating the requirement of endogenous iron for t-BuOOH toxicity.

Animals↗
PubMed1998

S-1153 inhibits replication of known drug-resistant strains of human immunodeficiency virus type 1.

S-1153 is a new imidazole compound that inhibits human immunodeficiency virus (HIV) type 1 (HIV-1) replication by acting as a nonnucleoside reverse transcriptase inhibitor (NNRTI). This compound inhibits replication of HIV-1 strains that are resistant to nucleoside and nonnucleoside reverse transcriptase inhibitors. S-1153 has a 50% effective concentration in the range of 0.3 to 7 ng/ml for strains with single amino acid substitutions that cause NNRTI resistance, including the Y181C mutant, and also has potent activity against clinical isolates. The emergence of S-1153-resistant variants is slower than that for nevirapine, and S-1153-resistant variants contained at least two amino acid substitutions, including F227L or L234I. S-1153-resistant variants are still sensitive to the nucleoside reverse transcriptase inhibitors zidovudine (AZT) and lamivudine. In a mouse and MT-4 (human T-cell line) in vivo HIV replication model, S-1153 and AZT administered orally showed a marked synergy for the inhibition of HIV-1 replication. S-1153 shows a significant accumulation in lymph nodes, where most HIV-1 infection is thought to occur. S-1153 may be an appropriate candidate for two-to three-drug combination therapy for HIV infection.

Animals↗
PubMed1998

Sequencing and characterization of the xyl operon of a gram-positive bacterium, Tetragenococcus halophila.

The xyl operon of a gram-positive bacterium, Tetragenococcus halophila (previously called Pediococcus halophilus), was cloned and sequenced. The DNA was about 7.7 kb long and contained genes for a ribose binding protein and part of a ribose transporter, xylR (a putative regulatory gene), and the xyl operon, along with its regulatory region and transcription termination signal, in this order. The DNA was AT rich, the GC content being 35.8%, consistent with the GC content of this gram-positive bacterium. The xyl operon consisted of three genes, xylA, encoding a xylose isomerase, xylB, encoding a xylulose kinase, and xylE, encoding a xylose transporter, with predicted molecular weights of 49,400, 56,400, and 51,600, respectively. The deduced amino acid sequences of the XylR, XylA, XylB, and XylE proteins were similar to those of the corresponding proteins in other gram-positive and -negative bacteria, the similarities being 37 to 64%. Each polypeptide of XylB and XylE was expressed functionally in Escherichia coli. XylE transported D-xylose in a sodium ion-dependent manner, suggesting that it is the first described xylose/Na+ symporter. The XylR protein contained a consensus sequence for binding catabolites of glucose, such as glucose-6-phosphate, which has been discovered in glucose and fructose kinases in bacteria. Correspondingly, the regulatory region of this operon contained a putative binding site of XylR with a palindromic structure. Furthermore, it contained a consensus sequence, CRE (catabolite-responsive element), for binding CcpA (catabolite control protein A). We speculate that the transcriptional regulation of this operon resembles the regulation of catabolite-repressible operons such as the amy, lev, xyl, and gnt operons in various gram-positive bacteria. We discuss the significance of the regulation of gene expression of this operon in T. halophila.

Amino Acid Sequence↗
PubMed1998

Hepatitis C virus RNA in dried serum spotted onto filter paper is stable at room temperature.

To overcome the instability of viral RNA, we carried out hepatitis C virus (HCV) RNA detection in dried serum spotted onto filter paper. The spotted serum samples were stored at room temperature and then processed for PCR assay at intervals of 1, 2, 3, and 4 weeks. The results showed that serum HCV RNA is stable in a dried condition, as it was detectable in spotted serum samples stored for 4 weeks at room temperature. Furthermore, although the HCV RNA titer showed an approximately 10-fold reduction in virus yield in dried serum stored at room temperature for 4 weeks, the PCR results of frozen serum samples and dried serum samples matched completely. This storage method facilitates transport and analysis by nucleic acid amplification techniques even when freezing conditions are not available.

Blood Specimen Collection↗