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T Kamiyama

Publications and source records attributed to T Kamiyama.

At least 37 records · Page 2Linked to original sources
PubMed1999

Polyol-induced molten globule of cytochrome c: an evidence for stabilization by hydrophobic interaction.

To address the contribution of hydrophobic interaction to the stability of molten globule (MG) of proteins, the effects of various polyols (ethylene glycol, glycerol, erythritol, xylitol, sorbitol, and inositol) on the structure of acid-unfolded horse cytochrome c were examined at pH 2, by means of circular dichroism (CD), partial specific volume, adiabatic compressibility, and differential scanning calorimetry (DSC). Addition of polyols induced the characteristic CD spectra of MG, the effect being enhanced with an increase in their concentration and chain length (the number of OH groups) of polyols except for ethylene glycol. The free energy change of MG formation by sorbitol was comparable with those for the salt-induced MG formation but the heat capacity change was negligibly small. The partial specific volume did not change within the experimental error but the adiabatic compressibility largely increased by MG formation. The sorbitol-induced MG showed a highly cooperative DSC thermogram with a large heat capacity change in comparison with the salt-induced one. These results demonstrate that polyols can stabilize the MG state of this protein through the enhanced hydrophobic interaction overcoming the electrostatic repulsion between charged residues. The stabilizing mechanism and structure of MG state induced by polyols were discussed in terms of the preferential solvent interactions and osmotic pressure of the medium, in comparison with the salt-induced one.

Calorimetry, Differential Scanning↗
PubMed1999

Emergence of resistance to acyclovir and penciclovir in varicella-zoster virus and genetic analysis of acyclovir-resistant variants.

We have characterized the differential actions of acyclovir and penciclovir against varicella-zoster virus (VZV) in cell culture by comparing the frequency of appearance of resistant viruses followed by their characterization. Cells were infected with cell-free virus and the cultures were successively treated with increasing concentrations of acyclovir or penciclovir. Drug-resistant viruses were selected in the presence of 6 microg/ml of acyclovir or penciclovir. The emergence frequency of resistant viruses was significantly higher following acyclovir exposure than following penciclovir exposure (Fisher's exact test, P<0.0001), possibly reflecting virus growth differences under these experimental conditions. Based on antiviral drug susceptibility and thymidine kinase (TK) activity assays, 11 acyclovir-resistant variants from seven experiments using three virus strains (Kawaguchi strain, Oka varicella vaccine strain and a clinical isolate from a zoster patient) were found to be TK-deficient. Sequence analysis of TK-deficient variants of the Kawaguchi strain revealed deletions that caused frameshifts, resulting in premature termination in the TK gene.

Acyclovir↗
PubMed1999

Elevated apoptosis of peripheral T lymphocytes in diabetic BB rats.

Thymocytes and peripheral lymphocytes of BioBreeding (BB) diabetes-prone (BBDP) and diabetes-resistant (BBDR) rat were analysed by fluorescence-activated cell sorter (FACS). The number of CD4- CD8-, CD4+ CD8-, CD4- CD8+ and CD4+ CD8+ subsets was not different between BBDP and BBDR rat thymocytes, whereas spleen and lymph nodes in BBDP rats undergo severe T-cell lymphopenia. Notably, mature CD4- CD8+ [T-cell receptor (TCR)-alphabeta+ and CD5+] cells are certainly present in the BBDP rat thymus, unlike some previous reports, suggesting that the differentiation of CD4- CD8+ from CD4+ CD8+ cells occurs normally in the BBDP rat thymus. As a cause of peripheral T-cell lymphopenia we suspected apoptosis of recent thymic emigrants. By FACS analysis with fluorescein isothiocyanate-labelled annexin V, elevated apoptosis was evident in BBDP rat peripheral lymphocytes. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) staining in BBDP rat splenic sections revealed that a number of TUNEL-positive cells were observed in the T-lymphocyte-rich area. From these results, we postulate that an abnormally elevated apoptosis of peripheral T lymphocytes, but not impaired thymocyte differentiation, is a cause of the peripheral T-cell lymphopenia in BBDP rats.

Animals↗
PubMed1999

Induction of CD8+ T cell-mediated protective immunity against Trypanosoma cruzi.

Trypanosoma cruzi was transformed with the Plasmodium yoelii gene encoding the circum-sporozoite (CS) protein, which contains the well-characterized CD8+ T cell epitope, SYVPSAEQI. In vivo and in vitro assays indicated that cells infected with the transformed T. cruzi could process and present this malaria parasite-derived class I MHC-restricted epitope. Immunization of mice with recombinant influenza and vaccinia viruses expressing the SYVPSAEQI epitope induced a large number of specific CD8+ T cells that strongly suppressed parasitemia and conferred complete protection against the acute T. cruzi lethal infection. CD8+ T cells mediated this immunity as indicated by the unrelenting parasitemia and high mortality observed in immunized mice treated with anti-CD8 antibody. This study demonstrated, for the first time, that vaccination of mice with vectors designed to induce CD8+ T cells is effective against T. cruzi infection.

Animals↗
PubMed1999

Hemodynamic and hormonal responses to nicorandil in a canine model of acute ischemic heart failure: a comparison with cromakalim and nitroglycerin.

The pharmacologic profiles of nicorandil in the cardiovascular system have been characterized by K-channel opening and nitrate activities. However, the effects of nicorandil on acute heart failure have yet to be elucidated. To investigate the effects of nicorandil under such pathophysiologic conditions, we administered nicorandil intravenously to dogs with acute ischemic heart failure induced by coronary embolization and compared the results with those induced by cromakalim and nitroglycerin. The heart failure in this experiment was demonstrated by a reduction of mean blood pressure (MBP) from 143+/-3 to 129+/-2 mm Hg (p < 0.01); cardiac output (CO) from 2.18+/-0.10 to 1.06+/-0.05 L/min (p < 0.01); stroke volume (SV) from 12.7+/-0.6 to 6.8+/-0.3 ml/min (p < 0.01); Vmax, an index of the contractility of the left ventricle, from 105.5+/-4.4 to 49.9+/-1.8 1/s (p < 0.01), and an increase in right atrial pressure (RAP) from 2.9+/-0.3 to 5.3+/-0.3 mm Hg (p < 0.01); left ventricular end-diastolic pressure (LVEDP) from 2.5+/-0.4 to 26.0+/-1.4 mm Hg (p < 0.01); and T, time constant of left ventricular relaxation, from 38.3+/-0.8 to 62.4+/-2.8 ms (p < 0.01). Furthermore, plasma renin activity (PRA) and plasma atrial natriuretic peptide (ANP) increased (from 1.72+/-0.29 to 5.03+/-0.68 ng AngI/ml/h, p < 0.01; from 103.9+/-5.8 to 411.5+/-29.4 pg/ml, p < 0.01, respectively), whereas brain natriuretic peptide (BNP) remained unchanged (from 23.1+/-2.2 to 26.9+/-1.4 pg/ml). Nicorandil (10-40 microg/kg/min, i.v. infusion for 20 min for each dosing) or cromakalim (0.25-1 microg/kg/min) decreased MBP, systemic vascular resistance (SVR), RAP, and LVEDP, and increased CO, SV, and Vmax. However, the reduction of RAP in cromakalim was significantly smaller than those of nicorandil and nitroglycerin in comparison at similar hypotensive doses. Nitroglycerin (2.5-10 microg/kg/min) decreased MBP, RAP, and LVEDP, and increased Vmax but did not change CO or SV. Increased plasma ANP levels, an index of cardiac filling pressure after induction of acute ischemic heart failure, were decreased significantly by cromakalim and tended to decrease by nicorandil or nitroglycerin. Plasma BNP levels and PRA were not influenced by any of these drugs. These results suggest that nicorandil produces the reduction of both preload and afterload followed by an improvement of cardiac contractility in this model. The increase in CO may be mediated mainly by the drug's K-channel opening activities and the reduction of venous tone by its nitrate properties. Nicorandil may prove to be useful in the treatment of acute ischemic heart failure.

Acute Disease↗
PubMed1999

Transforming growth factor beta-induced failure of resistance to infection with blood-stage Plasmodium chabaudi in mice.

The role of transforming growth factor beta (TGF-beta) in infection with Plasmodium chabaudi was investigated with resistant and susceptible mouse models. C57BL/10 mice produced gamma interferon (IFN-gamma) and nitric oxide (NO) shortly after infection and cleared the parasite spontaneously. In contrast, BALB/c mice showed a transient enhancement of TGF-beta production, followed by a relative lack of IFN-gamma and NO production, and succumbed to the infection. However, there was no correlation between levels of serum TGF-beta and splenic TGF-beta mRNA in both mouse strains before and after infection. Administration of recombinant TGF-beta (rTGF-beta) rendered resistant mice susceptible because of suppression of subsequent production of IFN-gamma and NO. Administration of anti-TGF-beta antibody to the infected BALB/c mice resulted in remarkable increases in serum IFN-gamma and NO, and the mice resisted the infection. Splenic CD4(+) T and CD11b+ cells of C57BL/10 mice were significantly activated after infection, but this was completely abrogated by administration of rTGF-beta. These results suggested that, in the P. chabaudi-susceptible but not resistant mice, production of TGF-beta was promoted, and subsequent failure of IFN-gamma- and NO-dependent resistance to the parasite was induced. This study is the first to indicate that TGF-beta production was the key event in failure of resistance to mouse malaria.

Animals↗
PubMed1999

Divergent effects of beta-blocker therapy on self-estimated and objectively scored activities of daily living.

To identify factors that influence changes in the activities of daily living (ADL) assessed by a standardized scoring system, ADL-20, and factors affecting the self-estimate of the changes in ADL, we conducted a 1-yr follow-up study of 1,163 outpatients aged 50 yr or older. The follow-up rate was 83.1%. A decrease in the ADL score was associated with advancing age and a lower prescription rate of beta-blockers. Analysis of the modalities of ADL revealed an association between a decreasing mobility score and a lower prescription rate of beta-blockers. In patients with impaired ADL at the time of enrollment, worsening of the ADL score was also associated with a lower baseline ADL score and a history of cardiovascular events. The prescription rate of diuretics was lower in patients who exhibited an improvement in ADL score. There was a considerable dissociation between the self-estimate of changes in ADL and the actual change in ADL-20 score. In more than 60% of patients with impaired baseline ADL, the self-estimate of changes was worse than the actual change in the ADL score. The "worse-than-actual" self-estimate of changes in ADL was associated with a higher prescription rate of beta-blockers. Thus, a history of cardiovascular events accelerates the aging-related deterioration of ADL. The use of a beta-blocker may worsen the self-estimate of the changes in ADL, while the actual ADL is preserved or slightly improved during beta-blocker therapy.

Activities of Daily Living↗
PubMed1999

Does the stomach remain silent after neonatal loss of its original pacemaker?: gastric motility in long-term survivors of neonatal gastric rupture.

Gastric peristaltic contractions are controlled by an intrinsic electrical pacemaker located in the mid-body along the greater curve. This study was undertaken to investigate gastric motility in long-term survivors of neonatal gastric rupture who were surgically deprived of their original pacemaker. Four patients, 1 boy and 3 girls, aged between 6 and 12 years were studied. Physiological activity of the gastric remnant was assessed in terms of electrical as well as peristaltic functions by means of electrogastrography and video-recorded barium swallow study. Electrical and mechanical pacing activities were classified into normogastria or dysrhythmia (brady- or tachygastria) according to their frequencies. In these patients, ectopic pacemakers were found to be arising just distal to the site of resection along the greater curve. Electrophysiologically, one patient was diagnosed as having normogastria, and other 3 patients were found to have dysrhythmia (2, bradygastria; 1, tachygastria) on the basis of electrogastrographic analyses. In two of three patients studied further by fluoroscopy, electrical activity agreed well with peristaltic activity. In one patient, however, electrical tachygastria was associated with peristaltic bradygastria. In conclusion, an ectopic pacemaker arises in the stomach that does not remain silent after neonatal surgical loss of its own pacemaker. Noninvasive electrogastrography seems useful in assessing electrical potentials generated by the ectopic pacemaker.

Barium↗
PubMed1999

An aged male patient with autoimmune hepatitis complicated by hepatocellular carcinoma.

An 82-year-old male patient was admitted for liver dysfunction. Laboratory test showed the following data; aspartate aminotransferase (AST) 79 IU/l, alanine aminotransferase (ALT) 28 IU/l, total bilirubin (T. Bil) 0.9 U, zinc sulfate turbidity test (ZTT) 48.9 U, gamma-globulin 4.9 g/dl, immunoglobulin G (IgG) 5,046 mg/dl, anti-nuclear antibodies x 320, anti-mitochondrial antibodies (-), hepatitis B virus surface antigen (HBsAg) (-), HBcAb (-), anti-hepatitis C virus (anti-HCV) (-), hepatitis C virus (HCV-RNA) (-), anti-hepatitis G virus (anti-HGV) (-), alpha-fetoprotein 306.8 ng/ml, carcinoembryonic antigen (CEA) 2.3 ng/ml, carbohydrate antigen (CA) 19-9 77.2 U/ml. Abdominal ultrasonography and computed tomography showed a large mass occupying most of the right lobe and portal thrombosis in the liver. Liver biopsy revealed cirrhosis with inactive hepatitis in the nontumorous lesion and well-differentiated hepatocellular carcinoma in the tumorous lesion. We report a rare case of an aged male patient with autoimmune hepatitis complicated by hepatocellular carcinoma.

Aged↗
PubMed1999

Factors related to impairment of activities of daily living.

OBJECTIVE: We examined the factors related to the impairment of activities of daily living (ADL). METHODS: ADL was evaluated by using ADL-20, which consists of 20 items from 4 major categories of activities; mobility, self-care, instrumental, and communication. The patients' gender, birth date, clinical diagnosis, past history, life styles, physical findings, laboratory data, and details of therapy were also recorded. Patients A total of 1,163 outpatients aged 50 years or older were included. Data from 1,093 patients were analyzed. RESULTS: We divided the subjects into two groups; Group I having full marks of ADL-20 (n=582) and group II exhibiting an impairment of ADL (n=511). Multiple logistic analysis revealed that in both sexes age and stroke were common independent factors related to the impairment of ADL. Other factors associated with impairment of ADL were smoking in men and presence of proteinuria in women. The presence of hyperlipidemia was associated with preservation of the ADL in women. CONCLUSION: The results demonstrated significant associations of smoking in men and the presence of proteinuria in women with the impairment of ADL in elderly Japanese outpatients. There appears to be a sex difference in the risk factors of impairment of ADL.

Activities of Daily Living↗
PubMed1999

Increased susceptibility of mice to malarial infection following UV-B irradiation.

Using a mouse model, we examined whether UV-B was a risk factor for malarial infection. Two mouse strains, susceptible (BALB/c) and resistant (C57BL/10) to murine malaria (Plasmodium chabaudi), were UV-preirradiated and infected with a sub-lethal dose of malaria parasite (104 and 105, respectively). Parasite growth was assayed with tail-blood smears counting parasitized red blood cells. Mice resistant to malaria were bled by heart puncture and the plasma cytokines were determined. Our results showed that UV-B irradiation worsened the malarial infection and 100% of the malaria-resistant mice strains died due to a usual infection at sub-lethal dose following UV-B irradiation. In the resistant mice strain infected with the parasite, the plasma IFN-gamma production was inhibited by UV-B irradiation and the maximum titer was about one-fifth of the non-irradiated mice. Furthermore, activation of macrophages from UV-irradiated mice also decreased compared with that of non-irradiated mice. IFN-gamma administration prevented the death of UV-B irradiated resistant mice and the cure ratio was 60%. In conclusion, UV-B increased the susceptibility of both strains of mice and impaired IFN-gamma production in the malaria-resistant mice strain.

Animals↗
PubMed1999

[Echinococcosis].

Explore the source record for details and available documents.

Albendazole↗
PubMed1998

Antipyretic activity of cinnamyl derivatives and related compounds in influenza virus-infected mice.

Kakkon-to is composed of seven medicinal herbs and exhibited novel antipyretic activity by suppressing interleukin-1alpha production responsive to interferon in a murine intranasal influenza virus infection model. Using this model, antipyretic compounds with such novel biological activities were characterized from the herbs. The organic solvent-extractable fractions of Cinnamomum cassia among the herbs showed antipyretic activity. We selected six antipyretic compounds from 48 cinnamyl derivatives and related compounds that may be mainly involved in the fractions. Their antipyretic activity was significantly correlated with interleukin-1alpha regulatory activity. Four of them suppressed interleukin-1alpha production to a basal level and showed different mode of antipyretic action from that of aspirin in interleukin-1alpha-injected mice. Structure-bioactivity relationship of the four suggested that an ester bond played an important role for both antipyretic and interleukin-1alpha regulatory activities. These compounds may be useful in analyzing interleukin-1alpha-producing cells in fever production and the mechanism of defervescence by suppressing interferon-induced interleukin-1alpha production.

Analgesics, Non-Narcotic↗
PubMed1998

A live non-neurovirulent herpes simplex virus vector expresses beta-galactosidase in the nervous system of the Wistar and Sprague-Dawley strain rat for a prolonged period.

We have constructed a live non-neurovirulent herpes simplex virus vector expressing beta-galactosidase under the control of the latency associated transcript promoter without inducing inflammation. Pathogenicity of the recombinant virus (betaH1) was not observed in the cutaneous, intravenous and intracerebral infection in mice. When betaH1 was inoculated at the caudate putamen of rats, beta-galactosidase activity was observed in neurons at the inoculation site and its projecting frontal cortex. Expression of beta-galactosidase was observed in the neurons of the innervating dorsal root ganglia 45 days after inoculation of betaH1 into the hind paws of the rats. Neither inflammation nor tissue destruction was observed in both neural tissues in this study. Thus this non-neurovirulent recombinant virus is a suitable vector for expressing the foreign genes in the nervous system for the prolonged period.

Animals↗
PubMed1998

Partial protection of severe combined immunodeficient mice against infection with Babesia microti by in vitro-generated CD4+ T cell clones.

Because CD4+ T cells were considered to be involved in protection against infection with Babesia microti, specific CD4+ T cells were generated in vitro from recovered BALB/c mice and their protective activity was tested in vivo. The cells produced varying amounts of interferon (IFN)-gamma in vitro in response to parasite antigen. In passive transfer experiments, three out of eleven T cell clones tested exerted protective activity in the early phase after infection. However, there seemed to be no correlation between this protection and in vitro IFN-gamma production by the T cell clones. Although the protection was partial and short-lived, the result provided direct evidence that CD4+ T cells play a crucial role in defense against B. microti.

Adoptive Transfer↗
PubMed1998

Coronary artery-pulmonary artery fistula originating from three major coronary branches associated with exertional chest pain and tachycardia-dependent left bundle branch block.

A 49-year-old male was admitted to our hospital because of chest pain. The pain occurred simultaneously with tachycardia-dependent left bundle branch block (LBBB) during exercise-stress and atropine-stress electrocardiogram (ECG) and on 24-h ambulatory ECG monitoring. Myocardial perfusion and metabolic scintigraphy with Tl-201 and I-123 BMIPP, respectively, showed no evidence of ischemia. Coronary arteriography revealed no atherosclerotic lesions, but did show a fistula between three major coronary arteries and the main pulmonary artery. The left-to-right shunt was undetectably small. Administration of diltiazem and metoprolol suppressed LBBB by attenuating the heart rate response to exercise, and reduced the chest pain. Therefore we presume that the exertional chest pain was not caused by myocardial ischemia but by the tachycardia-dependent LBBB. Coronary artery-pulmonary artery fistula is the most common type of coronary artery fistulae found incidentally in adulthood. Involvement of three major coronary branches is, however, rare. The case is discussed with a review of the literature.

Bundle-Branch Block↗
PubMed1998

An object-modeling method for hospital information systems.

Our goal is to increase the software productivity of hospital information systems (HISs) by applying object-oriented technologies. We propose a new object-modeling method for HISs that combines three general methods--an object modeling technique (OMT), class responsibilities collaboration (CRC) cards, and a use-case approach--to extract objects effectively. Our method also takes HIS functionality characteristics such as history and patient-staff linking into consideration to increase the reusability of objects. To test this method, we applied it to several HISs such as a drug-history system, a nursing-support system and an electronic patient record (EPR). We found that the software productivity of the drug-history system was more than doubled by using the combined method. Also, more than 40% of the logic classes could be reused in the nursing-support system and EPR. These findings confirmed that the proposed method can significantly increase the software productivity of HISs.

Clinical Pharmacy Information Systems↗