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Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 613 records · Page 34Linked to original sources
PubMed1996

Dobutamine stress echocardiography for detection of coronary artery stenosis in children with Kawasaki disease.

OBJECTIVES: This study was designed to assess the feasibility and diagnostic accuracy of dobutamine stress echocardiography for detection of coronary artery stenosis in children with Kawasaki disease. BACKGROUND: Dobutamine stress echocardiography is valuable as an alternative test for detection of coronary artery disease in adult patients; however, its usefulness for children has been demonstrated only in limited cases. METHODS: Dobutamine stress echocardiography (up to 30 microgram/kg body weight per min) was performed in 50 patients at the convalescent stage of Kawasaki disease, including 26 patients with coronary sequelae documented by previous coronary angiography (sequelae group, 3 to 15 years old) and 24 patients with normal coronary arteries documented by echocardiography (normal group, 7 to 16 years old), who underwent quantitative coronary angiography on a separate day. Left ventricular regional wall motion divided into 16 segments was assessed in relation to the extent of coronary artery disease. A positive test response was defined as a new or worsened wall motion abnormalities. RESULTS: Significant coronary artery disease (> or = 50% diameter stenosis of major vessels) was present in 21 patients in the sequelae group. There was no significant difference in the maximal dose of dobutamine between the sequelae and normal groups ([mean +/- SD] 22.4 +/- 5.1 vs. 24.2 +/- 2.5 microgram/kg per min). Heart rate and systolic blood pressure were significantly increased (p < 0.01) at maximal dose of dobutamine compared with values at rest in both groups; consequently, the rate-pressure product exceeded 20,000 in 20 (40%) of the 50 patients during dobutamine infusion. Ten patients had self-limiting side effects; however, there were no serious complications from stress-induced ischemia. New wall motion abnormalities corresponding to the extent of coronary artery disease were detected in 19 of 21 patients in the sequelae group, whereas no wall motion abnormalities were detected in the normal group. Thus, the sensitivity and specificity of dobutamine stress echocardiography for the detection of coronary artery disease were 90% and 100%, respectively. CONCLUSIONS: We conclude that dobutamine stress echocardiography is a safe and accurate diagnostic method for detection of coronary artery stenosis in Kawasaki disease. Moreover, this is a possible alternative method for patients unable to exercise adequately, even if they are small children.

Adolescent↗
PubMed1996

Epidemiology of bacterial meningitis in children: Aichi Prefecture, Japan, 1984-1993.

The details of 328 patients with bacterial meningitis, admitted from 1984 through 1993, were obtained from 46 departments of pediatrics of large hospitals through questionnaires. The incidence rate per 100,000 child-years was 2.32, being higher in children aged 0-4 years (rate, 7.22) than 5-15 years (rate, 0.49). The disease in the 274 (84%) etiologically diagnosed patients was due to Haemophilus influenzae (95), Streptococcus pneumoniae (56), Group B streptococci (GBS) (41), Escherichia coli (27), and other agents (55), including 7 patients with Mycobacterium tuberculosis infection. The short-term outcome (mean length of follow-up, 2 years, 11 months) of meningitis was death in 26 patients (8.2%) and sequelae in 49 (16.0%), including 26 children with multiple residual impairment. Tuberculous, pneumococcal, and GBS meningitis with a poor outcome increased during the late period (1989-1993) of the 10-year study. The annual infant mortality rate for purulent meningitis decreased from 3.7 to 1.4 per 100,000 population between 1984 and 1993. The incidence of a poor outcome (death and sequelae) in newborns decreased by half during the late period.

Adolescent↗
PubMed1996

Karyotyping by PFGE of clinical isolates of Sporothrix schenckii.

From October 1991 to December 1992 we had eight patients with sporotrichosis at Tsukuba University Hospital in Japan. With 8 strains isolated from these patients, PFGE (pulsed-field gel electrophoresis) analyses were carried out to examine whether the karyotype of S. schenckii is distinguished by our method and whether this molecular approach is a useful means of biotyping of S. schenckii strains. Chromosomes were separated by contour-clamped homogeneous electric field (CHEF) gel electrophoresis. The strains had six to eight chromosomes and a total genome size was approx. 28 Mbp. Although these karyotypes of all the isolates looked closely similar to each other, they were grouped into three types.

Electrophoresis, Gel, Pulsed-Field↗
PubMed1996

The role of low-density lipoprotein apheresis as postoperative care of bypass grafting for chronic arterial occlusion.

Since November 1989, low-density lipoprotein apheresis has been applied to patients with intractable hyperlipidaemia following bypass grafting for chronic arterial occlusion of the lower extremities. The treatment group comprised six patients (four men, two women) with arteriosclerosis obliterans. In five patients, the ankle pressure index deteriorated and intermittent claudication recurred due to atherosclerotic progression. Results of low-density lipoprotein apheresis were dramatic; the deteriorated ankle pressure index and intermittent claudication improved significantly after several applications of low-density lipoprotein apheresis. Significant angiographic improvement was obtained in two patients. It is concluded that low-density lipoprotein apheresis appears to be an efficient method to preserve graft patency and treat postoperative patients with deteriorated ankle pressure index.

Angiography↗
PubMed1996

Immunocytochemical localization of 60-kDa heat shock protein in Vibrio cholerae.

The immunocytochemical localization of the 60-kDa heat shock protein (HSP) in Vibrio cholerae strain 569B was studied by transmission electron microscopy using a combination with the antigen-specific monoclonal antibody (5C3) and immunogold labelling. The labelling with gold particles in V. cholerae detected 2 types; the gold particles were exclusively detected in the cytoplasm for one type and in the periplasmic space for another type, suggesting that the 60-kDa HSP of V. cholerae corresponding immunologically to Escherichia coli GroEL may translocate from the cytoplasm to the periplasmic space in the V. cholerae cell.

Animals↗
PubMed1996

The E280A presenilin 1 Alzheimer mutation produces increased A beta 42 deposition and severe cerebellar pathology.

Missense mutations in the presenilin 1 (PS1) gene cause the most common form of dominant early-onset familial Alzheimer's disease (FAD) and are associated with increased levels of amyloid beta-peptides (A beta) ending at residue 42 (A beta 42) in plasma and skin fibroblast media of gene carriers. A beta 42 aggregates readily and appears to provide a nidus for the subsequent aggregation of A beta 40 (ref. 4), resulting in the formation of innumerable neuritic plaques. To obtain in vivo information about how PS1 mutations cause AD pathology at such early ages, we characterized the neuropathological phenotype of four PS1-FAD patients from a large Colombian kindred bearing the codon 280 Glu to Ala substitution (Glu280Ala) PS1 mutation. Using antibodies specific to the alternative carboxy-termini of A beta, we detected massive deposition of A beta 42, the earliest and predominant form of plaque A beta to occur in AD (ref. 6-8), in many brain regions. Computer-assisted quantification revealed a significant increase in A beta 42, but not A beta 40, burden in the brains from 4 PS1-FAD patients compared with those from 12 sporadic AD patients. Severe cerebellar pathology included numerous A beta 42-reactive plaques, many bearing dystrophic neurites and reactive glia. Our results in brain tissue are consistent with recent biochemical evidence of increased A beta 42 levels in PS1-FAD patients and strongly suggest that mutant PS1 proteins alter the proteolytic processing of the beta-amyloid precursor protein at the C-terminus of A beta to favor deposition of A beta 42.

Age of Onset↗
PubMed1996

Umbilical vein endothelial cells are an important source of c-kit and stem cell factor which regulate the proliferation of haemopoietic progenitor cells.

The expression and production of c-kit and its ligand, stem cell factor (SCF), in cord blood and neonates were studied. Serum SCF levels were significantly higher in cord blood, neonates aged 1-30 d, and in 4-month-old infants than in the maternal serum (P < 0.01). SCF levels decreased in children from 7 months to 15 years of age (P < 0.01). The serum soluble c-kit levels were significantly higher in cord (P < 0.01) and neonatal blood (P < 0.05) than in the maternal blood. SCF and c-kit levels in placental tissue homogenates and the culture media of decidual cells and trophoblasts were low. To determine the sites of high SCF and c-kit production in cord blood and in early neonates. SCF and c-kit mRNA expression was analysed in various tissues by polymerase chain reaction. High SCF mRNA expression was observed in human umbilical vein endothelial cells (HUVEC). Moderate c-kit mRNA expression was detected in HUVEC, the bone marrow, and cord blood. These findings suggest that endothelial cells mainly produce the SCF in cord blood and in early neonates. To confirm the role of endothelial cells in haemopoiesis, colony-forming assays were performed in the presence of HUVEC culture media, which induced the formation of high numbers of granulocyte and erythroid colonies in cord blood. IL-3, IL-6 and SCF levels were elevated in the media. Our findings suggest that endothelial cells have an important role in the maintenance and proliferation of progenitor cells in neonatal blood via the interaction of c-kit and SCF with other factors. The ex vivo expansion of cord progenitor cells in the presence of endothelial cells needs to be investigated further.

ADP-ribosyl Cyclase↗
PubMed1996

Dopamine D2 receptor plays a critical role in cell proliferation and proopiomelanocortin expression in the pituitary.

BACKGROUND: It has been suggested that the dopaminergic system is involved in the inhibitory control of secretion of pituitary hormones and in the regulation of motor function in the striatum. To elucidate the specific role of the dopamine D2 receptor (D2R) in the pituitary and brain, we generated D2R deficient (D2R mutant) mice using the gene targeting method. RESULTS: Electrophysiological studies as well as ligand binding assays show no functional D2R in mutant mice. The D2R mutant mice display a hypoactivity and a slow, creeping movement. The expression of enkephalin mRNA in the striatum is increased in the mutant mice, but not that of dynorphin and substance P. D2R mutant mice have significantly darker coat colour than their wild-type littermates and show an elevation of plasma alpha-melanocyte stimulating hormone (alpha-MSH) levels. We found corresponding hyperplastic changes of intermediate lobe of the pituitary and the increased expression of pro opiomelanocortin (POMC) in the pituitary in D2R mutant mice. CONCLUSIONS: D2R plays a critical role in the inhibitory regulation of endocrine cell proliferation and the transcription of POMC mRNA, and consequently in the regulation of alpha-MSH in plasma. D2R might be involved in the regulation of enkephalin expression in the striatum, and hence might affect the movement and the behaviour.

Animals↗
PubMed1996

Gene frequencies of human platelet antigens on glycoprotein IIIa in Japanese.

BACKGROUND: Polymorphism of glycoprotein IIIa on human platelets is one of the factors in alloimmunization that causes neonatal alloimmune thrombocytopenia and refractoriness to platelet transfusion. STUDY DESIGN AND METHODS: DNA typing methods were originally developed to determine the genotypes of five human platelet antigen (HPA) systems located on glycoprotein IIIa: HPA-1, HPA-4, HPA-6W, HPA-7W and HPA-8W. The gene frequencies of these platelet antigens were determined by DNA typing of 331 unrelated Japanese donors. RESULTS: The gene frequencies of the low-frequency antigens were 0.002, 0.011, and 0.027 for HPA-1b, HPA-4b, and HPA-6W(b), respectively. All 331 Japanese donors tested were HPA-7W(a/a) and HPA-8W(a/a). Moreover, in the present study, none of the donors tested had two or more of these low-frequency antigens. CONCLUSION: The risk of neonatal alloimmune thrombocytopenia and refractoriness to platelet transfusion induced by the antigens of the HPA-1, HPA-7W, and HPA-8W systems was extremely rare in Japanese. However, attention must be paid to the involvement of the HPA-4 and HPA-6W systems in these clinical disorders.

Alleles↗
PubMed1996

The in-vitro activity of an antifungal antibiotic benanomicin A in comparison with amphotericin B.

Benanomicin A showed a broad antifungal spectrum, inhibiting the growth of all test strains of 41 yeasts, 23 dimorphic fungi, 23 dematiaceous fungi, 16 aspergilli, and 19 dermatophytes, with the exception of 12 zygomycetic strains. The MIC values of benanomicin A were comparable to those of amphotericin B against Cryptococcus. Rhodotorula, Trichosporon, Geotrichum, Sporothrix, and some dermatophytes, but were two to eightfold higher than those of amphotericin B against other fungal pathogens tested. The action of benanomicin A was fungicidal.

Amphotericin B↗
PubMed1996

Complete sequence, subunit structure, and complexes with pancreatic alpha-amylase of an alpha-amylase inhibitor from Phaseolus vulgaris white kidney beans.

The complete amino acid sequence of a white kidney bean (Phaseolus vulgaris) alpha-amylase inhibitor (PHA-I), which is composed of two kinds of glycopolypeptide subunits, alpha and beta, was established by conventional methods. The polypeptide molecular weight of PHA-I determined by the light-scattering technique, considered together with the sequence molecular weights revealed for the subunits, indicated that PHA-I has the subunit stoichiometry of (alpha beta)2 complex. Inhibition test of PHA-I with increasing amounts of porcine pancreatic alpha-amylase (PPA) suggested that an inactive 2:1 complex is formed between PPA and PHA-I. In fact, two complexes differing from each other in the molar ratio of PPA to PHA-I were separated by gel filtration, and molecular weight estimation by the light-scattering technique confirmed that they are complexes of PHA-I with one or two PPA molecules. The binding of PPA to PHA-I appeared to follow simple binomial statistics, suggesting that two binding sites on PHA-I are independent and of high affinity for PPA.

Amino Acid Sequence↗
PubMed1996

A chaperone-like function of intramolecular high-mannose chains in the oxidative refolding of bovine pancreatic RNase B.

This paper describes a chaperone-like function of the intramolecular N-glycans of bovine pancreatic RNase B. We studied air-oxidative regeneration from reductively denatured species of RNase B and its nonglycosylated form, RNase A. RNase B was reactivated much faster than RNase A, while RNase A was liable to aggregate during the regeneration. An Asn-linked oligosaccharide, Man5GlcNA2Asn, which corresponds to the most predominant sugar chain (ca. 60%) of RNase B, enhanced the reactivation of the denatured RNases A and B. The stimulatory effect of this Asn-oligosaccharide revealed that the N-glycans of RNase B facilitate the transformation of bulky intermediates into folded, compact species.

Animals↗
PubMed1996

Circulating parathyroid hormone-related protein (109-141) in malignancy-associated hypercalcemia.

For differential diagnosis between hypercalcemia-induced bone metastasis and humoral hypercalcemia of malignancy (HHM), serum parathyroid hormone-related protein (PTHrP) concentrations were measured in normal subjects and patients with malignancy-associated hypercalcemia according to the presence or absence of bone metastasis, using a new sensitive PTHrP(109-141) radioimmunoassay system. The serum PTHrP(109-141) levels in all of 14 patients without bone metastasis were significantly higher than those in normal subjects. However, in four patients with hypercalcemia associated with bone metastasis the levels were nearly the same as those in normal subjects. The time course in two hypercalcemic patients with esophageal carcinoma revealed that serum PTHrP(109-141) levels were elevated before hypercalcemia developed and that changes in PTHrP(109-141) and corrected serum calcium levels were significantly correlated. These findings suggest that determination of serum PTHrP(109-141) may be clinically important not only for differential diagnosis of HHM but also as a useful predictive marker of hypercalcemia.

Adolescent↗
PubMed1996

Flow cytometric analysis of the heat shock protein 60 expressed on the cell surface of Helicobacter pylori.

The expression of a 60-kDa heat shock protein (HSP60) on the cell surface of Helicobacter pylori was analysed by flow cytometry with polyclonal antibody directed to HSP60. All 13 strains of H. pylori examined expressed HSP60 on the cell surface, although the intensity of expression was different among the strains and depended on culture conditions. There was a correlation between the intensity of HSP60 expressed on the cell surface and the rate of adherence to human gastric carcinoma cells (MKN45) by H. pylori, but not with urease activity and production of vacuolating toxin. By flow cytometric analysis with monoclonal antibody (MAb) 3C8 against HSP60, the reactive epitope in the HSP60 of H. pylori was detected on the surface of MKN45 cells. Furthermore, it was shown that gastric epithelial cells were positively stained with MAb 3C8 in one of two biopsy specimens examined. These results suggest that there is a common epitope showing homology between H. pylori HSP60 and human gastric epithelial cells.

Animals↗
PubMed1996

Cooperative anti-Candida effects of lactoferrin or its peptides in combination with azole antifungal agents.

The effects of lactoferrin (LF), an antimicrobial protein secreted in body fluids, and its peptides in combination with azole antifungal agents were investigated by the micro-broth-dilution method in a study of Candida albicans. In the case of LF, its pepsin hydrolysate (LFhyd) or the LF-derived antimicrobial peptide Lactoferricin B (LF-B), the concentrations required to inhibit the growth of Candida decreased in the presence of relatively low concentrations of clotrimazole (CTZ). The minimum inhibitory concentration (MIC) of all azole antifungal agents tested was reduced by 1/4-1/16 in the presence of a sub-MIC level of each of these LF-related substances. Polyene and fluoropyrimidine antifungal agents did not show such a combined effect with these LF-related substances. The anti-Candida activity of LF or LF-B in combination with CTZ was shown to be synergistic by checkerboard analysis. These results indicate that LF-related substances function cooperatively with azole antifungal agents against C. albicans.

Antifungal Agents↗