Biomedical subjects

K Yamaguchi

Publications and source records attributed to K Yamaguchi.

At least 451 records · Page 25Linked to original sources

PubMed1999

Preoperative internal biliary drainage is superior to external biliary drainage in liver regeneration and function after hepatectomy in obstructive jaundiced rats.

OBJECTIVE: To examine the differences in regeneration rates and functions of the liver at the time of and after hepatectomy in obstructive jaundiced rats with preoperative external and internal biliary drainage. SUMMARY BACKGROUND DATA: The significance of biliary drainage before surgery is controversial in patients with obstructive jaundice. METHODS: After biliary obstruction for 7 days, rats were randomly divided into three groups: obstructive jaundice and hepatectomy (OJ-Hx), external biliary drainage and hepatectomy (ED-Hx), and internal biliary drainage and hepatectomy (ID-Hx). The OJ-Hx group underwent hepatectomy without biliary drainage; the other two groups underwent hepatectomy after biliary drainage for 7 days. At the time of hepatectomy, all rats were provided with internal biliary drainage. On days 0, 1, 2, 3, and 7 after hepatectomy, the DNA synthesis rate and the concentrations of adenine nucleotides and malondialdehyde in the liver were determined as markers of the hepatic regeneration rate, energy status, and lipoperoxide concentration, respectively. Portal endotoxin concentrations were measured and serum hyaluronic acid concentrations were determined as an indicator of hepatic endothelial function. RESULTS: The relative liver weight was significantly higher in the ID-Hx group than in the OJ-Hx group on days 1, 3, and 7 after hepatectomy and than in the ED-Hx group on days 1 and 2. The rate of hepatic DNA synthesis was significantly higher in the ID-Hx group than in the OJ-Hx and ED-Hx groups on day 1. The rate was similar in the ED-Hx and ID-Hx groups on day 2 but was significantly higher than in the OJ-Hx group. The hepatic malondialdehyde concentration was significantly higher on day 1 in the ED-Hx group than in the other two groups. It was lowest in the ID-Hx group throughout the study. Both biliary drainage procedures lowered the portal endotoxin concentration and serum hyaluronic acid concentration at the time of hepatectomy. The serum hyaluronic acid concentration was lowest in the ID Hx group. Hepatic adenine triphosphate concentrations and energy charge levels were similar among the three groups. CONCLUSION: Although both external and internal biliary drainage before hepatectomy improved serum liver function tests, portal endotoxin concentration, and serum hyaluronic acid concentration at the time of surgery, preoperative internal biliary drainage was superior to external drainage, as evidenced by the better liver regeneration and function after hepatectomy.

Animals↗

PubMed1999

The reversible change of GluR2 RNA editing in gerbil hippocampus in course of ischemic tolerance.

The ischemic tolerance is known to show protective effects on the neurons and the restricted Ca2+ influx through Ca2+ channels might be involved. In alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor, ribonucleic acid (RNA) editing of the GluR2 subunit determines receptor desensitization and Ca2+ permeability. The authors investigated the effect of ischemic tolerance on the messenger RNA editing of Q/R and R/G sites of GluR2 subunit in hippocampus. It was found that the rate of RNA editing in Q/R site showed no change (100% edited), whereas that in R/G site decreased significantly (83.3% normal editing level to 60.4%) at day 3 (preconditioning period) and returned to normal level at day 14 (after preconditioning period). Further investigation revealed that the decrease of editing rate in ischemic tolerance resulted mainly from the decrease of editing in CA1 area.

Animals↗

PubMed1999

Development of hepatocellular carcinoma in a patient with chronic hepatitis C after 6 years of a sustained and complete response to IFN-alpha.

The authors report a rare case of hepatocellular carcinoma (HCC) that developed 6 years after a sustained and complete response to interferon (IFN) therapy for chronic hepatitis C. A 61-year-old Japanese man presented with a mass in the liver that was diagnosed as HCC. Six years earlier he was treated with IFN-alpha and responded successfully to therapy, with sustained normalization of serum aminotransferases and eradication of serum hepatitis C virus (HCV)-ribonucleic acid (RNA). HCV-RNA was also not detected in the resected tumorous and nontumorous liver tissues. The findings suggest that all patients with chronic HCV infection should be followed closely for as long as possible for the potential development of HCC even after a complete and sustained response to IFN treatment.

Carcinoma, Hepatocellular↗

PubMed1999

Two germline missense mutations at codons 804 and 806 of the RET proto-oncogene in the same allele in a patient with multiple endocrine neoplasia type 2B without codon 918 mutation.

Multiple endocrine neoplasia (MEN) type 2B is a clinically distinct entity among the autosomal dominant MEN 2 syndromes. Most patients with MEN 2B carry a germline mutation (M918T) of the RET proto-oncogene, while a few carry A883F. We examined a patient with MEN 2B, but without M918T or A883F, and her relatives. Here, we report the presence in this patient of 2 germline mutations, V804M and Y806C in the same allele. While the novel Y806C was inherited from her father, its carriers (her father and brother) was not affected by MEN 2. In contrast, V804M was a de novo mutation, that has been reported in patients with familial medullary thyroid carcinoma. Combinations of mutations of the RET proto-oncogene may cause oncogenic activities different from those of single mutations.

Base Sequence↗

PubMed1999

[Enterococcus gallinarum septicemia in a patient with acute myeloid leukemia].

A 62-year-old male was admitted with complaints of fever and body weight loss. The patient was diagnosed as acute myeloid leukemia (M1) and chemotherapy was started. About 80 days after admission, the patient developed diarrhea with high fever. And E. gallinarum was isolated from the blood culture. We carried out PCR using primers for vanA, vanB and vanC in our E. gallinarum, and showed the existence of the vanC1. This organism should be considered as one of the possible pathogenes in the infectious complications of the immuno-compromized patient.

Bacteremia↗

PubMed1999

Fosfomycin alters lipopolysaccharide-induced inflammatory cytokine production in mice.

To determine the mechanisms of immunomodulating action of fosfomycin (FOF), we examined its effect on the production of inflammatory cytokines in mice injected with lipopolysaccharide (LPS). Treatment with FOF significantly lowered the peak serum levels of tumor necrosis factor alpha and interleukin-1 beta, indicating that FOF alters inflammatory cytokine production after LPS stimulation.

Animals↗

PubMed1999

Effect of antiflagellar human monoclonal antibody on gut-derived Pseudomonas aeruginosa sepsis in mice.

We evaluated the effect of antiflagellar human monoclonal antibody on gut-derived Pseudomonas aeruginosa sepsis. Mice were given a suspension of P. aeruginosa SP10052 in their drinking water and were simultaneously treated with ampicillin (200 mg/kg of body weight) to disrupt the normal bacterial flora. Cyclophosphamide was then administered to induce leukopenia and translocation of the P. aeruginosa that had colonized the gastrointestinal tract, thereby producing gut-derived generalized sepsis. In this model, intraperitoneal injection of 100 microg of antiflagellar human monoclonal antibody (SC-1225) per mouse for 5 consecutive days significantly (P < 0.01) increased the survival rate compared with that for mice treated with bovine serum albumin (BSA). Treatment with SC-1225 significantly reduced the average number of viable bacteria in portal blood, liver, and heart blood compared with the average number after treatment with BSA. Furthermore, the presence in serum of the inflammatory cytokines tumor necrosis factor alpha and interleukin 6 were evaluated as markers of severity of infection, and the results showed that the levels of these cytokines in mice treated with SC-1225 were significantly decreased in comparison with those in BSA-treated control mice. Although there was no significant difference in the number of bacteria that colonized the intestine, SC-1225 treatment significantly increased bacterial opsonophagocytosis by cultured peritoneal macrophages from mice with or without cyclophosphamide pretreatment. Our results indicate that antiflagellar human monoclonal antibody SC-1225 protects mice against gut-derived sepsis caused by P. aeruginosa and suggest that such an effect is due to its opsonophagocytic activity and the reduced motility of the translocated bacteria once the bacteria move from the intestine into the bloodstream.

Animals↗

PubMed1999

Detection of borna disease virus-reactive antibodies from patients with psychiatric disorders and from horses by electrochemiluminescence immunoassay.

The prevalence of Borna disease virus (BDV)-specific antibodies among patients with psychiatric disorders and healthy individuals has varied in several reports using several different serological assay methods. A reliable and specific method for anti-BDV antibodies needs to be developed to clarify the pathological significance of BDV infections in humans. We developed a new electrochemiluminescence immunoassay (ECLIA) for the antibody to BDV that uses two recombinant proteins of BDV, p40 and p24 (full length). Using this ECLIA, we examined 3,476 serum samples from humans with various diseases and 917 sera from blood donors in Japan for the presence of anti-BDV antibodies. By ECLIA, 26 (3.08%) of 845 schizophrenia patients and 9 (3.59%) of 251 patients with mood disorders were seropositive for BDV. Among 323 patients with other psychiatric diseases, 114 with neurological diseases, 75 with chronic fatigue syndrome, 85 human immunodeficiency virus-infected patients, 50 with autoimmune diseases including rheumatoid arthritis and systemic lupus erythematosis and 17 with leprosy, there was no positive case except one case each with alcohol addiction, AIDS, and dementia. Although 19 (1.36%) of 1,393 patients with various ocular diseases, 10 (1.09%) of 917 blood donors, and 3 (4.55%) of 66 multitransfused patients were seropositive for BDV-specific antigen, high levels of seroprevalence in schizophrenia patients and young patients (16 to 59 years old) with mood disorders were statistically significant. The immunoreactivity of seropositive sera could be verified for specificity by blocking with soluble p40 and/or p24 recombinant protein. Anti-p24 antibody was more frequent than p40 antibody in most cases, and in some psychotic patients antibody profiles showed only p40 antibody. Although serum positive for both p40 and p24 antibodies was not found in this study, the p40 ECLIA count in schizophrenia patients was higher than that of blood donors. Furthermore, we examined 90 sera from Japanese feral horses. Antibody profiles of control human samples are similar to that of naturally BDV-infected feral horses. We concluded that BDV infection was associated in some way with psychiatric disorders.

Age Distribution↗

PubMed1999

Primary Shewanella alga septicemia in a patient on hemodialysis.

We report the first Japanese case of primary septicemia with Shewanella alga and also describe the bacteriological characteristics of and results of antibiotic susceptibility tests of the isolate. S. alga was repeatedly isolated, at times simultaneously with Escherichia coli, from the blood of a 64-year-old female undergoing hemodialysis. The isolated organism was determined to be S. alga based on recently published identification criteria, such as hemolysis on sheep blood agar, no acid production from carbohydrates, and growth on agar containing 6. 5% NaCl. Results of antibiotic susceptibility tests demonstrated that the isolate was sensitive to levofloxacin and cefpirome (MICs, </=0.063) but resistant to cefazolin, ceftizoxime, and imipenem (MICs, >128, 64, and 8 microg/ml, respectively). Although the role of S. alga as a human pathogen has not been fully determined, accumulating data suggest that this organism may be a potential pathogen, especially in compromised hosts.

Anti-Bacterial Agents↗

PubMed1999

PDK1 homologs activate the Pkc1-mitogen-activated protein kinase pathway in yeast.

PDK1 (phosphoinositide-dependent kinase 1) is a mammalian growth factor-regulated serine/threonine kinase. Using a genetic selection based on a mutant form of the yeast MAP kinase kinase Ste7, we isolated a gene, PKH2, encoding a structurally and functionally conserved yeast homolog of PDK1. Yeast cells lacking both PKH2 and PKH1, encoding another PDK1 homolog, were nonviable, indicating that Pkh1 and Pkh2 share an essential function. A temperature-sensitive mutant, pkh1(D398G) pkh2, was phenotypically similar to mutants defective in the Pkc1-mitogen-activated protein kinase (MAPK) pathway. Genetic epistasis analyses, the phosphorylation of Pkc1 by Pkh2 in vitro, and reduced Pkc1 activity in the pkh1(D398G) pkh2 mutant indicate that Pkh functions upstream of Pkc1. The Pkh2 phosphorylation site in Pkc1 (Thr-983) is part of a conserved PDK1 target motif and essential for Pkc1 function. Thus, the yeast PDK1 homologs activate Pkc1 and the Pkc1-effector MAPK pathway.

3-Phosphoinositide-Dependent Protein Kinases↗

PubMed1999

Complement C1s activation in degenerating articular cartilage of rheumatoid arthritis patients: immunohistochemical studies with an active form specific antibody.

OBJECTIVE: The first complement component C1s was reported to have novel functions to degrade matrix components, besides its activities in the classic complement pathway. This study explores participation of C1s in articular cartilage degradation in rheumatoid arthritis (RA). METHODS: Normal articular cartilage (n = 6) and cartilage obtained from joints with RA (n = 15) and osteoarthritis (OA, n = 10) were immunostained using anti-C1s monoclonal antibodies PG11, which recognises both active and inactive C1s, and M241, which is specifically reactive to activated C1s. The effects of inflammatory cytokines on C1s production by human articular chondrocytes were also examined by sandwich ELISA. RESULTS: In normal articular cartilage, C1s was negative in staining with both PG11 and M241. In contrast, degenerating cartilage of RA was stained with PG11 (14 of 15 cases), and in most of the cases (13 of 15 cases) C1s was activated as revealed by M241 staining. In OA, C1s staining was restricted in severely degrading part of cartilage (5 of 10 cases), and even in that part C1s was not activated. In addition, C1s production by chondrocytes in vitro was increased by an inflammatory cytokine, tumour necrosis factor alpha. CONCLUSION: These results suggest that C1s activated in degenerative cartilage matrix of RA but not in that of OA. C1s is thought to participate in the pathogenesis of RA through its collagenolytic activity in addition to the role in the classic cascade.

Adolescent↗

PubMed1999

Nitric oxide differentially attenuates microvessel response to hypoxia and hypercapnia in injured lungs.

The issue of whether the acinar microvessel response to alveolar hypoxia and hypercapnia is impaired in injured lungs has not been vigorously addressed, despite the importance of knowing whether it is or not when treating patients with serious lung injury in terms of permissive hypercapnia. Applying a real-time laser confocal luminescence microscope, we studied hypoxia- and hypercapnia-induced changes in the diameter of the intra-acinar arterioles, venules, and capillaries of isolated rat lungs harvested from animals exposed for 48 h to 21% O(2) (group N) or 90% O(2) (group H). Measurements were made with and without inhibition of nitric oxide (NO) synthase (NOS) by N(omega)-nitro-L-arginine methyl ester or of cyclooxygenase (COX) by indomethacin at different basal vascular tones evoked by thromboxane A(2) (TXA(2)) analog. Hypoxia in the absence of TXA(2) contracted arterioles in group N but not in group H. Attenuated hypoxia-induced arteriole constriction was restored almost fully by inhibiting NOS and partially by inhibiting COX. Hypercapnia induced venule dilation in group N, but did not dilate venules in group H, irrespective of TXA(2). NOS inhibition in hypercapnia unexpectedly enhanced venule and arteriole dilation in group H. These responses no longer occurred when NOS and COX were inhibited simultaneously. In conclusion, microvessel reactions to hypoxia and hypercapnia are abnormal in hyperoxia-injured acini, in which NO directly attenuates hypoxia-induced arteriole constriction, whereas COX inhibited by excessive NO impedes hypercapnia-induced microvessel dilation.

Animals↗

PubMed1999

Bilirubin as an anti-oxidant for surgical stress: a preliminary report of bilirubin oxidative metabolites.

BACKGROUND: Bilirubin has been recognized as an anti-oxidant. The purpose of this study was to examine whether bilirubin would act as an antioxidant for surgical stress in humans. MATERIALS AND METHODS: Serum bilirubin and urinary bilirubin oxidative metabolites (BOM) were measured in 96 patients who underwent surgery. The antioxidant activity of bilirubin was assessed using BOM measured by enzyme-linked immunosorbent assay with an anti-bilirubin monoclonal antibody. RESULTS: Serum bilirubin levels increased after surgery in all 96 patients (p < 0.01), but did not correlate with operation time or blood loss (p = 0.53 and p = 0.28, respectively). BOM increased only in patients with major surgeries (p = 0.048). Significant correlations between BOM and operation time and blood loss were found (p < 0.01). CONCLUSIONS: Bilirubin appears to act as an antioxidant for invasive surgery in humans. Urinary BOM could be a reliable marker for the degree of surgical stress.

Adolescent↗

PubMed1999

Incomplete Sjögren-Larsson syndrome in two Japanese siblings.

Sjögren-Larsson syndrome (SLS) is a rare, autosomal recessive disorder characterized by ichthyosis, spastic diplegia and mental retardation. Biochemical studies have pinpointed the pathogenesis resulting in the deficiency of the fatty aldehyde dehydrogenase (FALDH) component of the fatty alcohol NAD+ oxidoreductase complex. Histochemical analysis revealed a reduction in alcohol dehydrogenase (AD) activity in the skin. SLS patients have been categorized biochemically into two groups: complete and incomplete reduction according to the degree of FALDH deficiency. Our patients demonstrated incomplete clinical features, including a 1/3 reduction in FALDH activity, and decreased AD activity in the ichthyotic lesion. The phenotypical differences between our cases and classic SLS are probably due to the partial FALDH deficiency.

Aldehyde Oxidoreductases↗

PubMed1999

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Journal Article↗

PubMed1999

Clinical and neuroradiological features of intracranial vertebrobasilar artery dissection.

BACKGROUND AND PURPOSE: We sought to determine the clinical and neuroradiological features of intracranial vertebrobasilar artery dissection. METHODS: The clinical features and MR findings of 31 patients (20 men and 11 women) with intracranial vertebrobasilar artery dissections confirmed by vertebral angiography were analyzed retrospectively. The vertebral angiography revealed the double lumen sign in 11 patients (13 arteries) and the pearl and string sign in 20 patients (28 arteries). RESULTS: The patients ranged in age from 25 to 82 years (mean, 54.8 years). Clinical symptoms due to ischemic cerebellar and/or brain stem lesions were common, but in 3 cases the dissections were discovered incidentally while an unrelated disorder was investigated. Headache, which has been emphasized as the only specific clinical sign of vertebrobasilar artery dissection, was found in 55% of the patients. Intramural hematoma on T1-weighted images has been emphasized as a specific MR finding. The positive rate of intramural hematoma was 32%. Double lumen on 3-dimensional (3-D) spoiled gradient-recalled acquisition (SPGR) images after the injection of contrast medium was identified in 87% of the patients. The 3-D SPGR imaging method is considered useful for the screening of vertebrobasilar artery dissection. CONCLUSIONS: Intracranial vertebrobasilar artery dissection is probably much more frequent than previously considered. Such patients may present no or only minor symptoms. Neuroradiological screening for posterior circulation requires MR examinations, including contrast-enhanced 3-D SPGR. Angiography may be necessary for the definite diagnosis of intracranial vertebrobasilar artery dissection because the sensitivity of the finding of intramural hematoma is not satisfactory.

Adult↗

PubMed1999

Plasma platelet-activating factor acetylhydrolase deficiency in Japanese patients with asthma.

Platelet-activating factor (PAF), a phospholipid with a wide range of proinflammatory actions, is immediately degraded and inactivated in vivo by PAF acetylhydrolase (PAF-AH). Surprisingly, 4% of the Japanese population lacks the extracellular isoform of this enzyme, plasma PAF-AH, due to a genetic missense (V279F) mutation. We studied the association of this mutation with asthma prevalence and phenotypes in the Japanese adult population. The allele frequency of V279F mutation was 18.6% in 279 patients with asthma (28.7% heterozygotes and 4.3% homozygotes) and 21.7% in 217 healthy subjects (32.3% heterozygotes and 5.5% homozygotes). V279F mutant allele prevalence was consistent regardless of asthma type (16.3% in atopic [n = 156] and 21.6% in nonatopic [n = 123]), or the severity of disease (21.7% in patients with mild [n = 97], 17.5% in those with moderate [n = 131], and 15.8% in those with severe [n = 51] asthma). Plasma PAF-AH activity was inversely proportional to the number of mutant alleles, and did not correlate with asthma prevalence, type, or severity. We concluded that plasma PAF-AH deficiency due to V279F mutation is not essential to the pathophysiology of asthma in the Japanese adult population.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed1999

Clinical and immunoregulatory effects of roxithromycin therapy for chronic respiratory tract infection.

The clinical and immunoregulatory effects of long-term macrolide antibiotic therapy for patients with chronic lower respiratory tract infections (CLRTI) were investigated. Clinical parameters and neutrophil chemotactic mediators in the epithelial lining fluid (ELF) of CLRTI patients (n = 10) were examined before and after 3 months oral administration of roxithromycin (RXM). The in vitro effects of RXM were also examined on the release of these mediators from alveolar macrophages (AM) and neutrophils. Arterial oxygen tension (p<0.05), vital capacity (VC) (p<0.001), %VC (p<0.05) and forced expiratory volume in one second (p<0.01) were improved after RXM treatment, but airway bacteria were not eradicated. Among the mediators, the levels of interleukin (IL)-8, neutrophil elastase (NE) and leukotriene B4 (LTB4) were higher in ELF than in plasma of CLRTI patients and they decreased after RXM treatment (n = 7, p<0.05 for each). RXM concentrations were significantly increased in the bronchoalveolar lavage cells of the treated patients. In in vitro experiments, RXM showed inhibitory effects on IL-8 release from AM and neutrophils. In conclusion, interleukin-8, neutrophil elastase and leukotriene B4 contribute to the neutrophilic inflammation in the airways of chronic lower respiratory tract infection patients and the clinical effects of roxithromycin may, in part, be attributable to the suppression of excess release of the chemotactic mediators from inflammatory cells.

Anti-Bacterial Agents↗