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Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 235 records · Page 13Linked to original sources
PubMed2000

Thiazolidinediones, dyslipidaemia and insulin resistance syndrome.

Insulin resistance is known to unite several metabolic abnormalities. The associated dyslipidaemia appears to play a central role in this atherogenic syndrome. Thiazolidinediones, which are recently introduced insulin sensitizing agents, have been shown to be effective not only in reducing elevated glucose levels, but also in improving the other metabolic abnormalities that are associated with insulin resistance. The present review focuses on these potential effects of thiazolidinediones.

Chromans↗
PubMed2000

X-ray structure of azide-bound fully oxidized cytochrome c oxidase from bovine heart at 2.9 A resolution.

Two azide ions were identified, one between the Fe and Cu atoms in the O(2)-reduction site and the other at the transmembrane surface of the enzyme, in the crystal structure of the azide-bound form of bovine heart cytochrome c oxidase at 2.9 A resolution. Two geometries, a mu-1,3 type geometry between the Fe and Cu atoms and a terminal geometry on the Fe atom, are equally possible for an azide ion in the O(2)--reduction site. The other azide molecule was hydrogen bonded to an amide group of an asparagine and a hydroxyl group of tyrosine in a mu-1,1 type geometry. The antisymmetric infrared bands arising from these azide ions, which show essentially identical intensity [Yoshikawa & Caughey (1992), J. Biol. Chem. 267, 9757-9766], strongly suggest terminal binding of the azide to Fe. The electron density of all three imidazole ligands to Cu(B) was clearly seen in the electron-density map of the azide-bound form of bovine heart enzyme, in contrast to the crystal structure of the azide-bound form of the bacterial enzyme [Iwata et al. (1995), Nature (London), 376, 660-669], which lacks one of the three imidazole ligands to Cu(B).

Animals↗
PubMed2000

Blood lysate staining, a new microscopic method for diagnosis of fungemia using peripheral blood.

We developed a microscopy method for the detection of fungal cells in peripheral blood, termed blood lysate staining, using an approximately 5x5 mm dotted blood lysate. This method was able to detect the emerging fungal pathogen Trichosporon asahii in murine models of systemic fungal infection and fungemia in patients quickly and at minimal cost. Pathogenic yeasts were successfully detected in 6 of 8 blood samples which were taken from feverish immunocompromised patients who were clinically suspected of having fungal infections. Fungal cells were observed as ovoid to elongated, 3x3 to 7x10 microm, and occurred singly, budding, and in short chains and clusters in a periodic acid-Schiff-stained blood smear. The yeast cells were easily distinguished from blood-cell debris by their size, shape and smooth yet rigid outline.

Animals↗
PubMed2000

First isolation of Stephanoascus ciferrii from a cat.

The present study deals with the first isolation of Stephanoascus ciferrii from a cat. A 2-year-old female Persian cat weighing 2.25 kg was referred to an animal hospital with a chief complaint of otitis externa of the left ear. Microscopic examination of specimen from the left ear disclosed yeast cells. The colony of the clinical isolate was cream-colored, rough, raised and wrinkled. The microscopic examination of the clinical isolate revealed abundant branched and septated mycelia with small ramified chains of oval blastoconidia, variable in size, and arranged alongside the hyphae. Amplification of the isolate DNA with LSU rDNA primers yielded a fragment of about 570 bp, whose nucleotide sequence of the isolate showed 100% similarity to that of Stephanoascus ciferrii in the GenBank database. Therefore, the isolate was identified as Stephanoascus ciferrii, confirming the result of mycological examination by molecular analysis.

Animals↗
PubMed2000

Does an early increase in heart rate during tilting predict the results of passive tilt testing?

Head-up tilt testing is a useful but time-consuming procedure. If we could accurately predict the tilt testing results; we would be able to substantially shorten the duration of tilt protocol. To clarify the hypothesis that an early increase in heart rate (HR) during tilting can predict the passive tilt results in our protocol (80-degree angle for 30 minutes), we studied 115 consecutive patients (72 men, 43 women, mean age 46 +/- 19 years) who were clinically diagnosed with neurally mediated syncope. Twenty-nine (25%) patients had a positive tilt test (P group), whereas 86 (75%) patients had a negative test (N group). The early HR increase was defined as the maximum HR during the first 5 minutes of tilting minus the resting HR before tilting. The early HR increase was significantly higher in the P group (23.8 +/- 9.5 beats/min) than in the N group (17.5 +/- 8.2 beats/min, P = 0.0008), but it was negatively correlated with the tilt duration to positive response (r = -0.52, P = 0.0032) and the patient age in the entire study population (r = 0.62, P < 0.0001). Results of multiple regression analysis indicated that age, tilt result, and tilt duration were independently associated with the early HR increase. As a result, an early HR increase > or = 18 beats/min, the best apparent cut-off point obtained in our study, was a sensitive (100%) marker for prediction of a positive response at < or = 15 minutes of tilting, but it showed a low specificity (61%). In conclusion, an early HR increase during 80-degree tilting may be only predictive for a positive result < or = 15 minutes because it depends on the tilt duration to a positive response and patient age.

Adolescent↗
PubMed2000

Circadian variation of vasovagal syncope.

INTRODUCTION: Circadian patterns have been demonstrated for several cardiovascular catastrophes. Chronobiologic factors play a role in the emergence of vasovagal syncope (VVS); however, diurnal variation of syncopal episodes in VVS has not been reported previously. METHODS AND RESULTS: We assessed daily distribution of the time of syncopal episodes in VVS. Time of syncope could be determined in 80 episodes in 54 patients (32 men and 22 women; mean age 37 years, range 12 to 67). Patients who were prescribed beta blockers or vasodilators, and who had syncopes related to alcohol intake, were excluded from the study. Head-up tilt testing was performed in 53 patients. The distribution of the episodes of VVS in 3-hour intervals differed significantly from uniform occurrence (P < 0.0001), with a peak frequency between 6 A.M. and noon (67.5% of total episodes). In patients who had experienced the initial syncope in the morning, most (78%) of the next syncopal episodes also occurred in the morning. There was no significant correlation between the time of last syncopes and tilt testing results. CONCLUSION: We demonstrated a prominent circadian variation in the frequency of VVS, with a peak in the morning. Recognition of the daily distribution of VVS is useful for patient education and therapeutic strategy.

Adolescent↗
PubMed2000

The chloroplast genomes of azuki bean and its close relatives: a deletion mutation found in weed azuki bean.

A physical map of the azuki bean (Vigna angularis cv. Erimo-shozu) chloroplast DNA (cpDNA) was constructed by localising the cleavage sites of PstI, SalI, SmaI, SacI, KpnI, PvuII and XhoI. The resulting map is more similar to the cpDNA-maps of two Vigna species (mung bean, V. radiata, and V. nakashimae) than to common bean (Phaseolus vulgaris) cpDNA map. Azuki bean was originally classified in the genus Phaseolus, and the inclusion of this taxon in the genus Vigna is a recent taxonomic decision. Our result is thus in favour of the taxonomic placement of azuki bean in the same genus as V. nakashimae and mung bean. We also found that a weed-form accession of azuki bean has a 96-bp deletion relative to the cultivar Erimo-shozu. The 96-bp deletion is located between the trnS-UGA and psbC genes in the large single-copy region of the chloroplast genome. This deletion is flanked by imperfect 9-bp direct repeats, suggesting that the deletion was a result of intra-molecular recombination mediated by these direct repeats.

Base Sequence↗
PubMed2000

Therapeutic efficacy of human macrophage colony-stimulating factor, used alone and in combination with antifungal agents, in mice with systemic Candida albicans infection.

We examined the in vivo activity of human macrophage colony-stimulating factor (hM-CSF) against lethal Candida albicans infection in mice. In C. albicans-infected mice which had been immunosuppressed with cyclophosphamide, treatment with hM-CSF at a daily dose of 8 x 10(5) units/kg of body weight or greater slightly but significantly prolonged survival. Furthermore, the therapeutic efficacy of amphotericin B (AMPH-B) in infected mice was enhanced by its combined use with hM-CSF, while that of fluconazole (FLCZ) was not. The activities of peritoneal macrophages and neutrophils from mice administered hM-CSF plus AMPH-B in combination for inhibition of hyphal growth of C. albicans cells and intracellular phagocytosis and killing of the cells were greater than those of comparable phagocytic cells from control mice to which hM-CSF plus AMPH-B was not administered. These results suggest that intravenous administration of hM-CSF augments the efficacy of AMPH-B by enhancing the antifungal activities of macrophages and neutrophils. Therefore, it is expected that therapy with the combination AMPH-B and hM-CSF could improve the efficacy of AMPH-B and reduce the therapeutic dose of the antifungal drug that is required.

Amphotericin B↗
PubMed2000

Functional analysis of the active site of a metallo-beta-lactamase proliferating in Japan.

An R-plasmid-mediated metallo-beta-lactamase was found in Klebsiella pneumoniae DK4 isolated in Japan in 1991. The nucleotide sequence of its structural gene revealed that the beta-lactamase termed DK4 was identical to the IMP-1 metallo-beta-lactamase which was mediated by a chromosomal gene of Serratia marcescens TN9106 isolated in Japan in 1991 (E. Osano et al., Antimicrob. Agents Chemother. 38:71-78, 1994). The dose effect of DK4 beta-lactamase production on the resistance levels indicated a significant contribution of the enzyme to bacterial resistance to all the beta-lactams except monobactams. The enzymatic characteristics of the DK4 beta-lactamase and its kinetic parameters for nine beta-lactams were examined. The DK4 beta-lactamase was confirmed to contain 2 mol of zinc per mol of enzyme protein. The apoenzyme that lacked the two zincs was structurally unstable, and the activities of only 30% of the apoenzyme molecules could be restored by the addition of 1 mM zinc sulfate. The substitution of five conserved histidines (His28, His86, His88, His149, His210) and a cysteine (Cys168) for an alanine indicated that His86, His88, and His149 served as ligands to one of the zincs and that Cys168 played a role as a ligand to the second zinc. Both zinc molecules contribute to the enzymatic process. Mutant enzymes that lack only one of these retained some activity. Additionally, a conserved aspartic acid at position 90 was replaced by asparagine. This mutant enzyme showed an approximately 1,000 times lower k(cat) value for cephalothin than that of the wild-type enzyme but retained the two zincs even after dialysis against zinc-free buffer. The observed effect of pH on the activity suggested that Asp90 functions as a general base in the enzymatic process.

Anti-Bacterial Agents↗
PubMed2000

Immune response against a cross-reactive epitope on the heat shock protein 60 homologue of Helicobacter pylori.

We previously established a monoclonal antibody (MAb), designated H9, which reacts with the heat shock protein 60 (HSP60) homologue of Helicobacter pylori as well as with other bacterial and human HSP60s. To determine the importance of a cross-reactive epitope on H. pylori HSP60 in H. pylori immunopathogenesis, we performed (i) mapping of an epitope on H. pylori HSP60 recognized by the H9 MAb, (ii) analysis of immunoglobulin G responses of patients with or without H. pylori infection to its epitope region, and (iii) studies of the protective effect of immunization with its epitope region on H. pylori infection in mice. The epitope recognized by the H9 MAb was mapped to the sequence of amino acids 189 to 203 (VEGMQFDRGYLSPYF) on the H. pylori HSP60 molecule. It was confirmed that the synthesized peptide designated pH9 was recognized by the H9 MAb. Enzyme-linked immunosorbent assay analysis showed that patients with H. pylori infection (n = 349) had significantly lower titers of pH9 antibody than did uninfected patients (n = 200) (P < 0.001), but this was not the case with purified H. pylori HSP60 recombinant Escherichia coli GroEL, or recombinant human HSP60. In C57BL/6 mice immunized with the pH9 peptide with Freund's complete adjuvant (FCA), the number of H. pylori organisms colonizing the stomach was significantly lower than that in mice immunized with pCont plus FCA (P < 0.0001) or FCA only (P < 0.005). The results suggest that the immune response to the cross-reactive epitope (pH9 region) on H. pylori HSP60 is unique and might be associated with protection against H. pylori infection.

Amino Acid Sequence↗
PubMed2000

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in the serum samples of workers at continuously burning municipal waste incinerators in Japan.

OBJECTIVES: To find whether concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in serum increased in workers at municipal incinerators that burn continuously. METHODS: 30 Workers employed at three municipal waste incineration plants (incinerator workers) and 30 control workers were studied. The incinerator workers had worn dust masks or airline masks during the periodic repair work inside the incinerators. Previous job, dietary habit, smoking habit, distance from residence to the incineration plant, and body weight and height were obtained from a questionnaire survey. Concentrations of PCDDs/PCDFs were measured in the serum of the workers and the dust deposited in the plants. The influence of various factors on serum concentrations of PCDDs/PCDFs was examined by multiple regression analysis. RESULTS: Dust analysis showed the greatest amount of octachlorodibenzo-p-dioxin (OCDD), followed by 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD), 1,2,3,4,6,7,8-heptachlorodibenzofuran (HpCDF), and octachlorodibenzofuran (OCDF). The toxicity equivalents (TEQs) of PCDDs and PCDFs in the deposited dust were 4.8, 1.0, and 6.4 ng TEQs/g, respectively, for plants A, B, and C. The mean serum TEQs of PCDDs and PCDFs in the incinerator workers and control workers were 19.2 and 22.9 pg TEQs/g lipid, respectively, for area A, 28.8 and 24.5 pg TEQs/g lipid for area B, and 23.4 and 23.6 pg TEQs/g lipid for area C. No significant differences were found between the incinerator workers and the controls for TEQs of PCDDs and PCDFs separately, and TEQs of PCDDs and PCDFs together. However, the serum 1,2,3,4,6,7,8-HpCDF concentration was significantly higher in the incinerator workers than in the controls for all the three areas. When the exposure index to 1,2,3,4,6,7,8-HpCDF is defined as the product of the concentration of 1,2,3,4,6,7,8-HpCDF in the deposited dust and duration of employment, the concentration of 1,2,3,4,6,7,8-HpCDF in serum increased as the exposure index increased. Multivariate analysis suggested that the serum concentration of HpCDF increased with duration of employment at the incineration plants and OCDF increased with employment of > or = 21 years. The other significant variables (p < 0.01 or p < 0.001) were area for hexachlorodibenzo-p-dioxin (HxCDD) and tetrachlorodibenzofuran (TCDF), Brinkman index for HpCDD, and body mass index (BMI) for tetrachlorodibenzo-p-dioxin (TCDD), HpCDD, and TEQs of PCDDs. CONCLUSION: The serum TEQs of PCDDs and PCDFs was not significantly higher among the incinerator workers, but the serum concentration of 1,2,3,4,6,7,8-HpCDF was. This suggests that the incinerator workers had inhaled dust containing PCDDs and PCDFs while working in plants equipped with incinerators that burn continuously.

Adult↗
PubMed2000

Effects of transdermal nicotine treatment on structure and function of coronary artery bypass grafts.

Smoking is a major risk factor for failure of coronary artery bypass grafts (CABG). Experiments were designed to determine effects of transdermal nicotine, independent of smoking, on structure and function of CABG. Saphenous veins were placed as CABG in untreated dogs (control) or in dogs treated with transdermal nicotine (one 11-mg or two 22-mg patches/day) for 5 wk. Serum nicotine and plasma nitric oxide were measured. Grafts were removed and prepared for organ chamber studies and histology. Serum nicotine averaged 12.1 and 118.7 ng/ml in the 11 mg/day and 44 mg/day groups, respectively. Plasma nitric oxide was higher in dogs treated with 11 mg/day doses compared with controls. In organ chamber studies, endothelium-dependent relaxations to thrombin and A-23187 and endothelium-independent relaxations to nitric oxide were greatest in grafts from dogs treated with 11 mg/day doses. Intimal thickness of the grafts were similar among groups. However, staining for bone sialoprotein was increased in the media of grafts from the 11 mg/day treatment group. These data suggest that transdermal nicotine in doses comparable and double to those used for conventional smoking cessation treatment in humans does not adversely affect early patency of canine CABG up to 4 wk postoperatively. Transdermal nicotine, however, may increase production of and response to nitric oxide in bypass grafts.

Actins↗
PubMed2000

Expression of Lewis(a), sialyl Lewis(a), Lewis(x) and sialyl Lewis(x) antigens as prognostic factors in patients with colorectal cancer.

BACKGROUND: Altered expression of blood group-related carbohydrate antigens such as sialyl Lewis (Le)(x) antigen in tumours is associated with tumour progression behaviour and subsequent prognosis. However, the prognostic value of the expression of Le-related antigens in colorectal tumours remains unclear. PURPOSE: To clarify the prognostic value of Le(a), sialyl Le(a), Le(x) and sialyl Le(x) expression in colorectal carcinomas as prognostic factors after surgery. PATIENTS AND METHODS: Colorectal carcinoma samples from 101 patients with primary colorectal carcinoma who underwent surgical resection were subject to immunohistochemical analyses for Lea, sialyl Lea, Lex and sialyl Le(x) expression with the respective monoclonal antibodies. RESULTS: Le(a), sialyl Le(a), Le(x) and sialyl Le(x) were expressed in 69 (68.3%), 73 (72.3%), 66 (65.4%) and 76 (75.3%) carcinomas, respectively. The patients with sialyl Lex-expressing tumours had more advanced cancer than those with nonsialyl Lex-expressing tumours (P=0.0029). The survival time after surgery of patients with Le(x)- or sialyl Le(x)-expressing tumours was significantly shorter than the survival time of those with non-Le(x)- or nonsialyl Le(x)-expressing tumours, respectively (P=0.023 and P=0. 0001, respectively). Cox's regression analysis revealed that Le(x) and sialyl Le(x) expression, separate from stage and histological type, were prognostic variables for patient survival (hazard ratio [HR] for sialyl Le(x)-positive expression to sialyl L(x)-negative expression 2.90; HR for Le(x)-positive expression to Le(x)-negative expression 12.76 in stage I/IV, 0.63 in stage II and 1.69 in stage III). CONCLUSIONS: Le(x) expression and sialyl Le(x) expression in colorectal carcinomas are each associated with poor prognosis. These variables should be considered in the design of future trials.

Colorectal Neoplasms↗
PubMed2000

Different expression of sialyl Tn antigen between polypoid and nonpolypoid growth types of advanced colorectal carcinoma.

Colorectal tumors can be classified based on their growth pattern into the polypoid growth type (PG-type) and nonpolypoid growth type (NPG-type). We examined sialyl Tn antigen expression in advanced colorectal carcinomas that were classified as PG-type and NPG-type cancers in order to ascertain whether or not such expression correlates with other biologically and clinically important differences. A total of 94 advanced colorectal carcinomas were examined for sialyl Tn antigen expression, which was immunohistochemically detected by the monoclonal antibody TKH2. Univariate and multivariate analyses using logistic regression models were performed. Forty carcinomas (42.6%) were negative and 54 (57.5%) were positive for sialyl Tn antigen. Eighteen carcinomas (19.2%) were of PG type and 76 (80.8%) of NPG type. NPG-type cancers had a higher proportion of positive lymph node metastasis than PG-type cancers. Furthermore, sialyl Tn antigen was less often detected in NPG-type cancers (39 of 76; 51.3%) than in PG-type cancers (15 of 18; 83.3%; p = 0.0167). Multivariate analysis showed that two variables, lymph node metastasis and sialyl Tn antigen expression in carcinoma, were independently related to tumor growth patterns, that is NPG type and PG type. These data suggest that the difference in sialyl Tn antigen expression between two kinds of tumor growth patterns of advanced colorectal carcinomas, PG type and NPG type, may reflect different biological behaviors during tumor progression.

Aged↗
PubMed2000

High prevalence of seropositivity for antibodies to Chlamydia-specific lipopolysaccharide in patients with acute coronary syndrome.

BACKGROUND: Results of recent studies have demonstrated that there is an association between infection with Chlamydia pneumoniae and coronary artery disease (CAD). Inflammatory response caused by chlamydial infection has been considered to contribute to the development of atherosclerosis in coronary arteries. OBJECTIVE: The aim of this study was to investigate the specific relations between chlamydial infection and coronary events in patients with CAD. METHODS: We measured serum levels of immunoglobulin A and G antibodies against Chlamydia spp.-specific lipopolysaccharide in 155 patients with CAD and 60 age-matched and sex-matched healthy controls by enzyme-linked immunosorbent assay. CAD patients were divided into groups of the patients with acute coronary syndrome [(ACS), n = 35], old myocardial infarction [(OMI), n = 60] and chronic coronary heart disease [(CCHD), n = 60]. RESULTS: Prevalence of both seropositive antibodies in the control group and CCHD group were not different. In contrast, in ACS group there were significantly higher prevalences of seropositive immunoglobulin A (46 versus 12%, P = 0.0001) and G (74 versus 45%, P = 0.005) antibodies and in OMI group there was a significantly higher prevalence of seropositive immunoglobulin A antibodies (28 versus 12%, P = 0.02). Furthermore, compared with CCHD group, in ACS group there were significantly higher prevalences of seropositive immunoglobulin A (P = 0.00006) and G (P = 0.002) antibodies and in OMI group there was a higher prevalence of seropositive immunoglobulin A (P = 0.01). Adjustment for confounding factors did not change these findings. CONCLUSIONS: Infection with Chlamydia is significantly associated with ACS and OMI, but not with CCHD. These findings suggest that chronic and reactive infection with Chlamydia can lead to disruption of vulnerable plaque in patients with ACS.

Acute Disease↗
PubMed2000

Activation of the sodium pump blocks the growth hormone-induced increase in cytosolic free calcium in rat adipocytes.

GH promptly increases cytosolic free calcium ([Ca2+]i) in freshly isolated rat adipocytes. Adipocytes deprived of GH for 3 h or longer are incapable of increasing [Ca2+]i in response to GH, but instead respond in an insulin-like manner. Insulin blocks the GH-induced increase in [Ca2+]i in GH-replete cells and stimulates the sodium pump (i.e. Na+/K+-ATPase), thereby hyperpolarizing the cell membrane. Blockade of the Na+/K+-ATPase with 100 microM ouabain reversed these effects of insulin and enabled GH to increase [Ca2+]i in GH-deprived adipocytes. Both insulin and GH activated the sodium pump in GH-deprived adipocytes, as indicated by increased uptake of 86Rb+. Decreasing availability of intracellular Na+ by blockade of Na+/K+/ 2Cl- symporters or Na+/H+ antiporters abolished the effects of both hormones on 86Rb+ uptake and enabled both GH and insulin to increase [Ca2+]i in GH-deprived adipocytes. The data suggest that hormonal stimulation of Na+/K+-ATPase activity interferes with activation of voltage-sensitive calcium channels by either membrane hyperpolarization or some unknown interaction between the sodium pump and calcium channels.

Adipocytes↗
PubMed2000

Saponins of plants of Panax species collected in Central Nepal, and their chemotaxonomical significance. III.

Panax pseudo-ginseng subsp. pseudo-ginseng has a carrot like root with a small rhizome. It was shown that the saponin composition of roots and rhizomes of this subspecies collected in Tibet and China was extremely poor. From the roots and rhizomes collected in Central Nepal, (specimen-PNct), only a small amount of an oleanolic acid saponin, beta-D-glucopyranosyl-oleanolate (2) was isolated together with a polyacetylene-alcohol, panaxynol (3). In another specimen (specimen-PNs), also collected in Central Nepal, two oleanolic acid saponins, stipleanoside R2 (4) and chikusetsusaponin IV (5) were detected. No dammarane saponin was identified in either specimen. P. pseudo-ginseng subsp. himalaicus (Subsp-H) has a big rhizome with a small round root. From rhizomes and roots of this subsp. collected in Central Nepal (specimen-HNct), a fairly large amount of dammarane saponins, ginsenosides-Rb1 (6), -Rd (7), -Re (9) and -Rg1 (10), gypenoside XVII (8), notoginsenoside-R1 (11), majonoside-R2 (12) and pseudo-ginsenoside-F11 (13) were isolated, while no oleanane saponin (oleanolic acid saponin) was identified in this subsp. Based on the present and previous studies, medicinal evaluation and chemogeographical correlation of Himalayan Panax spp. are discussed.

Chromatography, High Pressure Liquid↗