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Biomedical subjects

K Hara

Publications and source records attributed to K Hara.

At least 289 records · Page 16Linked to original sources
PubMed1998

Anti-CD8 monoclonal antibody protects against spontaneous IgA nephropathy in ddY mice.

We investigated the effects of anti-CD4 monoclonal antibody (mAb) and/or anti-CD8 mAb in ddY mice, an animal model of spontaneous IgA nephropathy. Female ddY mice were treated with 18 intravenous injections of anti-CD4 and/or anti-CD8 mAb at 2-week intervals. This was based on our observation that a single injection of anti-CD4 mAb or anti-CD8 mAb caused a selective depletion in CD4+ T cells for 2 weeks and CD8+ T cells for 4 weeks, respectively. The level of proteinuria, serum IgA, and changes in the histopathological features of renal tissue samples were assessed in treated mice between the age of 4 and 40 weeks. The level of proteinuria increased with age, but there was not significant difference among the groups. No animal developed microhematuria throughout the study. Treatment with anti-CD4 mAb produced a mild to moderate level of mesangial hypertrophy at 20 and 40 weeks, similar to the results in untreated mice. The lowest degree of mesangial hypertrophy occurred in mice treated with anti-CD8 mAb up to the age of 40 weeks. Treatment with a combination of anti-CD4 and anti-CD8 mAbs produced effects that were similar to those observed on treatment with anti-CD8 mAb alone. Our results suggest that CD8+ T cells mediate mesangial proliferation and the progression of nephropathy in ddY mice.

Animals↗
PubMed1998

TATA-less mouse vitronectin gene promoter: characterization of the transcriptional regulatory elements and a nuclear protein binding site on the promoter.

Vitronectin in a cell-adhesion molecule whose expression is temporally and spatially regulated in vivo, but whose regulatory mechanism of transcription is unknown. In this study, we characterized the mouse vitronectin gene promoter. Luciferase expression vectors cloned the successive 5'- or 3'-deletions of the 5'-flanking region upstream of the luciferase gene and were transfected into the human hepatoma cell line HepG2. The assay of luciferase activity in the transfected cells revealed that a 38 base pair (bp)-element (positions +3 to +40) displays promoter activity. A consensus sequence consisting of a TATA box and initiator is shown around the transcription initiation site of the mouse vetronectin gene, but the GC box is not shown. Site-directed or deleted mutagenesis against a consensus sequence of TATA box and initiator could not abolish the promoter activity. These results induce that the putative TATA box and initiator are not involved in the promoter activity, and that the vitronectin promoter lacks the TATA box, initiator and GC box. To characterize trans-acting factors involved in promoter activity, a DNA fragment (position -74 to +95) was subjected to gel shift assay using nuclear proteins extracted from HepG2 cells. One shifted band was detected by the gel shift assay, suggesting that a nuclear protein binds to the promoter region. Results of the DNase I foot printing assay and gel shift assay demonstrate that the nuclear proteins can bind to the 38 bp-element, which has promoter activity. The nuclear protein is a putative trans-acting factor involved in transcription initiation.

5' Untranslated Regions↗
PubMed1998

Expression of cytokine mRNA in extrahepatic organs in a mouse concanavalin A-hepatitis model.

The liver injury in the concanavalin A (Con A)-induced mouse hepatitis model has been well studied. However, there has been little study on the effects of Con A on extrahepatic organs. The aim of the present work was to determine the effects of Con A on the spleen, kidney and lung. A histopathological study showed that Con A (15 mg/kg, i.v.) administration affects not only the liver, but also all these extrahepatic organs. Messenger RNA expression was studied by the using polymerase chain reaction. Treatment with Con A induced interleukin-2 mRNA in the spleen, but only slightly induced it in the kidney. The mRNAs of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) were induced in all these organs. At 24 hr after Con A treatment, the expression of IFN-gamma mRNA, but not that of TNF-alpha mRNA, was inhibited by cyclosporine A (50 mg/kg, i.p.), suggesting that Con A induced these cytokine mRNAs through different mechanisms. In the kidney and lung, CD4+ and CD8+ T-cell infiltration was suggested by the Con A-induced CD4 and CD8 mRNAs. The present study showed the histopathological effects of Con A and Con A-induced cytokine mRNA expression on the spleen, kidney and lung.

Animals↗
PubMed1998

Induction of CPP32-like activity and inhibition of interleukin 1beta converting enzyme activity in the liver of a mouse concanavalin A-induced hepatitis model.

The objective of the present study was to determine the effects of concanavalin A (Con A) administration on the interleukin 1beta converting enzyme (ICE) activity and CPP32-like activity in mouse liver. Treatment with Con A (0.2 mg/mouse, i.v.) caused an elevated plasma alanine aminotransferase (ALT) level at 8 hr after Con A injection. ICE activity was decreased at 8 and 24 hr after Con A treatment. In contrast, CPP32-like activity was increased at 24 hr after Con A injection. Since CPP32-like activity was induced after ALT had increased, the induction of CPP32-like activity may not be involved in Con A-induced hepatitis.

Amino Acid Chloromethyl Ketones↗
PubMed1998

Effect of gadolinium chloride treatment on concanavalin A-induced cytokine mRNA expression in mouse liver.

The effect of Kupffer cell depression on concanavalin A (Con A)-induced cytokine mRNA expression in the liver was studied. Gadolinium chloride (GdCl3) is a commonly used Kupffer cell inhibitor. GdCl3 (40 mg/kg, i.p.) was injected into each mouse, and 24 hr later, Con A (0.2 mg/mouse) was administered. Plasma was obtained at 24 hr after Con A treatment for alanine aminotransferase (ALT) measurement. GdCl3 treatment inhibited Con A-induced elevation of ALT. However, it did not inhibit Con A-induced interleukin-2 or tumor necrosis factor-alpha mRNA expression. The present results suggest that Kupffer cells are not responsible for Con A-induced cytokine expression in the liver.

Alanine Transaminase↗
PubMed1998

Effects of concanavalin A treatment on CD8 mRNA expression in mouse liver.

The administration of concanavalin A (Con A) (0.2 mg/mouse) into mice induced significant elevation of plasma alanine aminotransferase (ALT) at 8.5 hr after Con A treatment. CD8 mRNA, which is a marker of cytotoxic T-cell, was strongly induced at 16 and 24 hr after Con A treatment. Although pretreatment with cyclosporine A (CsA) (50 and 100 mg/kg, i.p.) inhibited Con A-induced elevation of plasma ALT, it did not inhibit Con A-induced CD8 mRNA expression. Morphological study revealed lymphoid cell infiltration in the liver, but the lymphoid cells were not present at the site of hepatocyte necrosis. These results suggest that Con A-induced CD8+ T-cell infiltration has a minimal effect in the development of hepatitis.

Alanine Transaminase↗
PubMed1998

Cryptosporidiosis in Indonesia: a hospital-based study and a community-based survey.

Hospital-based and community-based studies were conducted to understand the prevalence and mode of transmission of Cryptosporidium parvum infection in Surabaya, Indonesia. In both studies people with and without diarrhea were examined for oocysts. A community-based survey included questionnaires to a community and stool examination of cats. Questionnaires covered demographic information, health status, and hygienic indicators. In the hospital, C. parvum oocysts were found in 26 (2.8%) of 917 patients with diarrhea and 15 (1.4%) of 1,043 control patients. The most susceptible age was less than two years old. The prevalence was higher during the rainy season. A community-based study again showed that C. parvum oocysts were frequently detected in diarrhea samples (8.2%), exclusively during rainy season. Thirteen (2.4%) of 532 cats passed C. parvum oocysts. A multiple logistic regression model indicated that contact with cats, rain, flood, and crowded living conditions are significant risk factors for Cryptosporidium infection.

Adolescent↗
PubMed1998

[Measurement of levels of plasma endothelin-1 and serum nitrate anion in patients with sepsis].

Recently much attention has been paid to the circulatory disturbance and peripheral vascular damage in patients with sepsis and septic shock. We intended to elucidate the interaction between nitric oxide (NO) and endothelin (ET)-1 under various pathological conditions by measuring the concentrations of NO3-, the principal metabolite of NO and immunoreactive ET-1. In cases with good prognosis after the septic shock, ET-1 was significantly higher as compared with these in sepsis without shock. In lethal cases with septic shock, these parameters were abnormally high as compared with the survived case. These levels elevated as the degree of severity progressed. When patients recovered from the septic shock, plasma ET-1 levels rapidly decreased. These results may mean that the level of the concentration of ET-1 plays a key role for prevention of the multiple organ failure even after the recovery from septic shock. The elevated level of NO3- during the initial several days in septic shock will mean that NO is acting to prevent platelet aggregation and to keep blood flow by dilating the arteries during septic shock. On the contrary, it may also be suggested that the elevated level of NO3- and ET-1 leads to the dysfunction of vascular endothelial cells and the apoptosis.

Adult↗
PubMed1998

[Palmaz-Schatz stent implantation for aorto-ostial stenoses of native coronary arteries and saphenous vein grafts].

Conventional balloon angioplasty treatment of aorto-ostial stenoses in native coronary arteries and saphenous vein grafts is associated with a low primary success rate, a high complication rate and a high incidence of restenosis. The short-term outcome of Palmaz-Schatz stent implantation in aorto-ostial lesions was compared with that of balloon angioplasty. Thirteen patients underwent stent implantation for 13 de novo lesions (four in the left main coronary trunk, two in the right coronary artery, seven in the vein graft) between January 1994 and December 1995. Fourteen patients underwent balloon angioplasty for 14 de novo lesions (five in the left main coronary trunk, four in the right coronary artery, five in the vein graft between January 1986 and April 1992. Both groups had similar clinical characteristics. Initial success was obtained in all patients in the stent group, compared with 71% of the balloon angioplasty group. Insufficient dilation was the main cause for such failure in the balloon angioplasty group. Baseline reference diameters were similar (3.40 +/- 0.65 mm in the stent group vs 3.36 +/- 0.42 mm in the balloon angioplasty group) and there was no difference in baseline minimal luminal diameter (1.41 +/- 0.74 vs 1.08 +/- 0.56 mm). Minimal luminal diameter was significantly greater in the stent group than in the balloon angioplasty group at both post-procedure and follow-up examinations (post: 3.36 +/- 0.58 vs 2.69 +/- 0.45 mm, p < 0.01; follow-up: 2.33 +/- 0.96 vs 1.52 +/- 0.68 mm, p < 0.05). There was no subacute occlusion in either group. The overall angiographic restenosis rate (> 50% stenosis) was lower in the stent group (17%) than in the balloon angioplasty group: the restenosis rates of native lesions were 0% in the stent group and 40% in the balloon angioplasty group; those of saphenous vein graft lesions were 33% in the stent group and 50% in the balloon angioplasty group. Although the number of patients was limited, these results suggest that Palmaz-Schatz stent implantation may be a safe and effective strategy for treating aorto-ostial lesions in both native coronary arteries and saphenous vein grafts.

Angioplasty, Balloon, Coronary↗
PubMed1998

Resting muscle sympathetic nerve activity does not predict duration of symptom-limited submaximal exercise in young patients with dilated cardiomyopathy.

OBJECTIVE: To determine whether increased sympathetic vasoconstrictor drive to the calf in heart failure is associated with reduced symptom-limited submaximal exercise performance. DESIGN: Blood pressure, heart rate and peroneal muscle sympathetic nerve activity (MSNA) were recorded during rest and before symptom-limited treadmill exercise at 70% of resting heart rate reserve for up to 45 mins. PATIENTS: Thirteen young patients with dilated cardiomyopathy (age 36 +/- 2 years). RESULTS: MSNA (45 +/- 6 bursts/min) was more than double the level documented in an age-, sex- and weight-matched group of normal subjects studied under identical baseline conditions. Patients with ventricular dysfunction exercised for 30 +/- 3 mins on average, but exercise distance and duration were independent of resting MSNA. CONCLUSIONS: In young patients with dilated cardiomyopathy, sympathetic nerve traffic to the calf vascular bed, measured at rest, does not predict the distance or duration of symptom-limited submaximal treadmill exercise.

Adult↗
PubMed1998

Effects of FGFs on the morphogenic potency and AER-maintenance activity of cultured progress zone cells of chick limb bud.

The apical mesodermal region of chick limb buds (progress zone, PZ) which is essential for limb pattern formation contains uncommitted cells that change their positional values instructed by the apical ectodermal ridge (AER). Reciprically, the PZ cells maintain the AER activity. FGF-2 and FGF-4 can substitute for the AER to maintain normal outgrowth and gene expression in the limb bud. We examined the effects of FGF on the maintenance of PZ cells characteristics in culture by making recombinant limbs with anterior PZ cells that were pre-cultured in the presence of FGF-2 or FGF-4 and analyzed their morphogenic potency and responsiveness to positional cues arising from the zone of polarizing activity (ZPA). The limb buds expressed distal Hox genes and could form a segmented digit. Recombinant limb buds consisting of anterior PZ cells cultured without FGF failed to express Hox genes and formed instead a small cartilage nodule. These results indicate that addition of FGF-2 or FGF-4 to cultured PZ cells maintains their competence for Hox gene expression and digit formation, but not their responsiveness to positional cues from the ZPA. We also found that when anterior PZ cells which had been pre-cultured with FGF-2 or FGF-4 were implanted underneath the AER, they could maintain Fgf-8 expression in the AER, whereas this expression was not detected in the AER on the grafted anterior PZ cells that had been pre-cultured without FGF, indicating that FGF maintains AER-maintenance activity of PZ cells in culture.

Animals↗
PubMed1998

Purification and characterization of a novel dipeptidase from carp ordinary muscle.

A novel dipeptidase was purified to homogeneity from the crude extract of carp ordinary muscle with an increase in specific activity of 4041-fold and a 4% recovery rate. The enzyme was determined to have molecular weights of 54,000 after reduction and 106,000 without reduction, indicating that it is composed of two sulfide-linking molecules of subunit peptide chains of identical molar size. The optimum hydrolysis pH and temperature of the enzyme were evaluated by l-leucine-glycine to be pH 8.5 and 40 degreesC, respectively, and it was markedly stable in the weak alkaline region and at temperatures below 30 degreesC. Dipeptide hydrolysis of the enzyme was inhibited by metalloprotease inhibitors, sulfide-specific reagents, metal chelating reagents and reductants. In addition, sulfide-affinity bivalent metals potently inactivated the enzyme, while Mg2+ and Mn2+ activated it to different extents, and Mn2+ was also effective on the restoration of the nearly completely inactivated enzyme. The enzyme had a broad range of action on dipeptides that are composed of only l-amino acids, such as l-leucine, l-methionine, l-phenylalanine, and l-valine at the C-terminal and l-alanine, l-leucine, l-methionine, and l-valine at the N-terminal, but it had no catalytic action on dipeptides containing l-proline and d-amino acids, tripeptides, and peptide derivatives.

Journal Article↗
PubMed1998

Distinctive catalytic actions of carp dipeptidases from ordinary muscle and intestine.

Although carp muscular and intestinal dipeptidases are metalloenzymes acting only on dipeptides, some structural and enzymatic differences occur between them. The present study verifies distinctive actions during dipeptide hydrolysis by these enzymes in terms of their kinetic characterization. The intestinal enzyme was differentially inhibited by EDTA and 1,10-phenanthroline, whereas these compounds induced a similar level inhibition of the muscular enzyme. The Km and Vmax values of both enzymes for l-leucine-glycine hydrolysis varied during incubations with 1,10-phenanthroline and EDTA, and the Km or Vmax values of the intestinal enzyme increased or remained the same with increasing concentrations of 1,10-phenanthroline, respectively. Analysis of the kinetic parameters indicated that Co2+ and Mn2+ had noncompetitive effects on the muscular enzyme and that a noncompetitive activation on the intestinal enzyme was stimulated by 1.5 mM of Mg2+ and with increasing concentrations of Mn2+. The muscular enzyme acted on a wide range of l-configuration dipeptides, whereas the intestinal enzyme acted only on a select range of dipeptides with a hydrophobic amino acid at the N-terminal position. The Kcat/Km values of both enzymes for dipeptide hydrolysis showed that highly hydrophobic dipeptides served as their preferential substrates. Other kinetic parameters demonstrated distinctive hydrolytic action of the two enzymes on these dipeptides: a strong affinity of the low catalytic rate muscular enzyme, and a weak affinity of the high catalytic rate intestinal enzyme.

Journal Article↗
PubMed1998

[A survey of opioid use in preanesthetic medication].

A mailing survey was carried out to assess the current practice of sedative premedication in anesthesia. Questionnaires were sent by mail to 77 university hospitals. We especially evaluated use of opioids for premedication. Sixty-one percent (n = 47) of the hospitals answered these questionnaires and 31 percent (n = 15) of them were using opioids for the preanesthetic medication. Pethidine was used most frequently for premedication of all opioids, and morphine was often used for the premedication before cardiac surgery. All opioids were administrated intramusculary both in adults and children.

Adolescent↗
PubMed1998

Utility of caffeine analysis for forensic hair discrimination.

Utility of caffeine analysis for the purpose of forensic hair discrimination was evaluated. Methanol extracts of each 5-cm strand of scalp hair, after its incubation at 37 degrees C for 15 h, was analyzed by gas chromatography-mass spectrometry (GC-MS). For quantitative analysis of caffeine, caffeine-d3 was added as internal standard to the methanol extract. Hair specimens were obtained from three victims and from twenty-two volunteers. The results showed that caffeine levels in hair varied according to each individual; caffeine was detected up to a maximum level of 4.19 ng/5-cm hair. The concentrations of caffeine in hair obtained from four different regions of the scalp in twenty-two volunteers showed a coefficient of variation not greater than 24.7% for each individual. Based on our data, it was concluded that caffeine levels give relatively high reliability for discriminating a victim's hair from others at a criminal or accidental scene, although it should be used in combination with morphological examination and ABO blood group determination.

ABO Blood-Group System↗
PubMed1997

Regulation of eIF-4E BP1 phosphorylation by mTOR.

The proteins eIF-4E BP1 and p70 S6 kinase each undergo an insulin/mitogen-stimulated phosphorylation in situ that is partially inhibited by rapamycin. Previous work has established that the protein known as mTOR/RAFT-1/FRAP is the target through which the rapamycin.FKBP12 complex acts to dephosphorylate/deactivate the p70 S6 kinase; thus, some mTOR mutants that have lost the ability to bind to the rapamycin.FKBP12 complex in vitro can protect the p70 S6 kinase against rapamycin-induced dephosphorylation/deactivation in situ. We show herein that such mTOR mutants also protect eIF-4E BP1 against rapamycin-induced dephosphorylation, and for both p70 S6 kinase and eIF-4E BP1, such protection requires that the rapamycin-resistant mTOR variant retains an active catalytic domain. In contrast, mutants of p70 S6 kinase rendered intrinsically resistant to inhibition by rapamycin in situ are not able to protect coexpressed eIF-4E BP1 from rapamycin-induced dephosphorylation. We conclude that mTOR is an upstream regulator of eIF-4E BP1 as well as the p70 S6 kinase; moreover, these two mTOR targets are regulated in a parallel rather than sequential manner.

Animals↗
PubMed1997

Role of spinal GABA receptors in depressor responses to chemical stimulation of the A5 area in normal and hypertensive rats.

Chemical stimulation of neurons in the pontine A5 area by microinjection of L-glutamate lowers arterial blood pressure. The mechanism of this 'A5 depressor response' is not well-established. Here, we examine the involvement of spinal cord gamma-aminobutyric acid (GABA) receptors in this depressor response in normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Experiments were conducted in male WKY and age-matched SHR anaesthetised with sodium pentobarbitone and chloral hydrate. An intrathecal catheter was implanted with the tip located between T9 and L2. Three days later, rats were re-anaesthetised and 10 nl of 40 mM L-glutamate was injected into the A5 area before, during and after, blockade of spinal cord GABA-A receptors by intrathecal injection of bicuculline methiodide (1 mM in 10 microliters phosphate-buffered saline). Injection of L-glutamate (10, 20, 40, 80 mM in 10 nl) produced depressor responses that were similar in WKY (n = 6) and SHR (n = 6). Intrathecal injection of bicuculline elicited a pressor response that was greater in SHR (n = 7, 28.5 +/- 7.6% increase in mean arterial pressure) than WKY (n = 11, 11.6 +/- 3.6%, p < 0.05). After bicuculline, the depressor response to injection of L-glutamate into the A5 area was eliminated in both WKY (n = 7) and SHR (n = 6). Intrathecal injection of vehicle had no effect on either resting arterial blood pressure or the depressor response to A5 stimulation. Basal blood pressure and control responses to A5 stimulation were fully restored by around 90 min after bicuculline injection in each animal. In separate groups of rats, intrathecal injection of muscimol elicited depressor responses that were greater in SHR (n = 6, -32.0 +/- 6.2%) than WKY (n = 6, -17.3 +/- 1.5%, p < 0.05). Our results suggest that the A5 depressor response is due to a projection from the A5 area to the spinal cord. This projection acts directly, or through a spinal interneuron and uses GABA as a neurotransmitter. Furthermore, our results indicate a hyper-responsiveness to GABA-A receptor stimulation in SHR since intrathecal bicuculline elicited much greater increases and intrathecal muscimol elicited much greater decreases, in blood pressure in SHR than in WKY. Finally, it seems likely that the A5-spinal depressor pathway is less effective in SHR than WKY under physiological conditions since chemical stimulation of the A5 area with L-glutamate produced a comparable depressor response in both strains.

Animals↗