Biomedical subjects

J Yamaguchi

Publications and source records attributed to J Yamaguchi.

At least 37 records · Page 2Linked to original sources

PubMed2000

Lifestyle factors affecting bone ultrasonometry of the calcaneus in Japanese women.

Ultrasonometry is increasingly used to assess bone characteristics. A group of 1412 women with a mean age of 57 years attended a screening examination in a Japanese city. Seventy-four percent of participants were postmenopausal. Broadband ultrasound attenuation (BUA), speed of sound (SOS), and Stiffness index (SI) of the calcaneus were measured; subjects also completed a questionnaire examining lifestyle factors; anthropometric data were recorded. Analysis showed that the strongest predictors of decreased BUA, SOS, and SI were increased age and menopausal status. Higher body mass index and current participation in exercise or sports were significant predictors of increased BUA, SOS, and SI in a multivariate model. Higher calcium intake predicted increased BUA (P = 0.004) and missing meals predicted a lower SOS (P = 0.019). This study suggests that dietary factors as well as physical activity influence bone characteristics assessed by QUS. QUS may be a suitable technique to assess the effect of lifestyle changes on bone.

Adult↗

PubMed2000

Hepatic resections for bilobar liver metastases from colorectal cancer.

The present study was performed to assess survival benefits in patients who underwent a hepatic resection for isolated bilobar liver metastases from colorectal cancer. Thirty-eight patients underwent a curative hepatic resection for isolated colorectal liver metastasis. Among them, 11 patients had bilobar liver metastases and 19 had a solitary metastasis. The remaining 8 patients had unilobar multiple lesions. We investigated survival in two groups those with bilobar and those with solitary metastatic tumors. Survival and disease-free survival were 36% and 18% at 5 years, respectively, in the patients with bilobar liver metastases, while these survivals were 43% and 34% in the patients with solitary liver metastasis. In the 38 patients, repeated hepatic resections were performed in 15 patients with recurrent liver disease. The 5-year survival and disease-free survival rates for these patients were 38% and 27%, respectively, after the second hepatic resections. Of the 11 patients with bilobar liver metastases, 5 underwent a repeated hepatic resection, and they all survived for over 42 months. Based on our observations, a hepatic resection was thus found to be effective even in selected patients with either bilobar nodules or recurrence in the remnant liver.

Adult↗

PubMed2000

Characterization of isoforms of hexose kinases in rice embryo.

Hexose kinases in rice embryos have been characterized. Six isoforms were detected: i.e. three glucokinases (GK1-3), two hexokinases (HK1 and HK2) and one fructokinase (FK1). Out of these, GK3, HK1 and HK2 were inhibited by mannoheptulose and glucosamine, known inhibitors of hexokinase activity. These inhibitors are also known to be modulators of sugar sensing processes. The results suggest that GK3, HK1 and HK2 may play a role in sensing the cellular sugar status in the rice embryo.

Fructokinases↗

PubMed2000

Radial magnetic resonance imaging and pathological findings of acetabular labrum in dysplastic hips.

Radial MRI findings and pathological changes were comparatively examined in the acetabular labrum of 11 hips of 11 patients, who underwent total hip arthroplasty for osteoarthritis due to acetabular dysplasia. Diffuse high signal pattern on the radial MR images corresponded to histological degeneration of the labrum. High signal pattern which was equivalent to the synovial fluid, showed an intralabral tear. In the obscure areas of MR images, severe impairment of the labrum such as rupture, detachment, and displacement were found.

Journal Article↗

PubMed2000

Anti-CD4 induced rat heart tolerance: no presence of primed T cells and regulatory mechanisms for cytotoxic T cells.

Treatment with anti-CD4 monoclonal antibody (mAb) (OX38) induces heart, but not skin graft tolerance in WF (RT1u) to Lewis (RT1l) rat strain combinations. We examined differences in cellular responses between heart-bearing and skin-rejected hosts that were both treated with anti-CD4 mAb. In the tolerant LEW rats bearing WF heart transplants, the secondary WF heart but not skin grafts were accepted. On the other hand, in anti-CD4 treated WF skin-rejected hosts, both secondary WF heart and skin grafts were rapidly rejected. Spleen cells from anti-CD4 treated WF skin-rejected LEW rats but not from WF heart-bearing LEW rats received the same treatment generated CTL after in vitro stimulation with paraformaldehyde (PFA) treated donor WF stimulator spleen cells. Adoptive transfer of spleen cells from WF skin-rejected LEW rats with or without anti-CD4 therapy into the tolerant LEW rats at the secondary WF heart transplantation blocked the secondary heart graft acceptance. However, transfer of spleen cells from WF heart-rejected rats without immunosuppression failed to block acceptance of the secondary heart graft. Our results indicated the lack of primed T cells and presence of regulatory mechanisms for tissue specific T cells in anti-CD4 treated heart bearing hosts.

Animals↗

PubMed2000

Distribution and characterization of enzymes causing starch degradation in rice (Oryza sativa cv. koshihikari).

The thermal dependency and stability of enzymes producing reducing sugar (RS) were examined in bran, the exterior 13% part (outer endosperm), and the remaining inner endosperm of rice grains. RS-producing enzymes in the inner endosperm showed a higher optimum temperature than those in other parts of the rice grain. Diethylaminoethyl-Sephacel chromatography of crude extracts revealed two peaks of RS-producing activity with different optimum temperatures (60 and 37 degrees C) in all three parts. alpha-Glucosidase (EC 3.2.1.20) and alpha-amylase (EC 3.2.1.1) isoform G were thought to be major components of the RS-producing activities with high and low optimum temperatures, respectively. The peak with a high optimum temperature was a more abundant component in the inner endosperm, compared with other parts of the rice grain. Thus, different parts of rice were found to have distinct enzyme sets having different thermal dependency and to be involved in starch degradation to various sugars.

Carbohydrate Metabolism↗

PubMed2000

Glucose modulates the abscisic acid-inducible Rab16A gene in cereal embryos.

Glucose effects on the expression of the abscisic acid-inducible Rab16A gene were examined in rice and barley embryos. Glucose feeding to rice embryos negatively affects the endogenous abscisic acid content and represses the promoter activity of the Rab16A gene. Glucose repression of the Rab16A gene takes place both at a transcriptional and a post-transcriptional level. Modulation of the abscisic acid content in rice embryos triggered by glucose did not directly influence the expression of the rice alpha-amylase gene RAmy3D, which is known to be under glucose control. The possible interaction between the glucose and abscisic acid signaling pathway is discussed.

Abscisic Acid↗

PubMed2000

Glucose repression of alpha-amylase in barley embryos is independent of GAMYB transcription.

The induction of alpha-amylase triggered by gibberellic acid in barley embryos is repressed by sugars. We investigated the effects of glucose on the gibberellin signal transduction pathway to localize the site of interaction of the sugar/hormone signalling pathways. Our results indicate that glucose represses gibberellin signalling late along this hormone transduction pathway, downstream of transcription of the gibberellin-modulated transcriptional activator (GAMYB) needed for alpha-amylase induction. This result suggests either that glucose repression is transduced by a pathway independent of gibberellin signalling or that repression occurs at the level of GAMYB translation.

Gene Expression Regulation, Enzymologic↗

PubMed2000

A novel murine anti-human Fas mAb which mitigates lymphadenopathy without hepatotoxicity.

Defects in Fas-mediated apoptosis are implicated in autoimmune diseases including rheumatoid arthritis (RA). Although induction of Fas-mediated apoptosis could have therapeutic effects on these diseases, it might cause deleterious effects in liver as Fas ligand or an agonistic anti-murine Fas antibody Jo2 causes severe hepatic injury in mice. We report here on the interesting characteristics of the newly obtained anti-Fas mAb, HFE7A, which cross-reacts with the Fas molecules of various species ranging from human to mouse and mitigates autoimmune symptoms without hepatotoxicity in mice. The administration of HFE7A to mice induced apoptosis in the thymocytes, although administration of HFE7A to mice or to marmosets did not induce any sign of hepatitis. The effect of HFE7A on liver is different from that of anti-murine Fas antibody Jo2, which causes acute and lethal hepatic injury to mice. Administration of HFE7A reduced lymphadenopathy and abnormal T cells in MRL-gld/gld mice. HFE7A induced apoptosis in synovial cells prepared from RA patients. Surprisingly, HFE7A protected mice from fulminant hepatitis induced by Jo2. Therefore, HFE7A is a potential therapeutic antibody not only for autoimmune diseases including RA but also for fulminant hepatitis.

Animals↗

PubMed2000

Characterization and expression of monosaccharide transporters (osMSTs) in rice.

This study deals with the cloning and characterization of monosaccharide transporter cDNAs in rice. OsMST1-3 (Oryza sativa monosaccharide transporters 1-3) have two sets of putative six transmembrane domains separated by a central long hydrophilic region. Heterologous expression of OsMST3 in the yeast Saccharomyces cerevisiae indicated that OsMST3 has transport activity for some monosaccharides in an energy-dependent H+ co-transport manner. Northern blot and in situ hybridization analyses showed that OsMST3 mRNA is detectable in leaf blades, leaf sheaths, calli and roots, especially the xylem as well as in sclerenchyma cells in the root. These results suggested that OsMST3 is involved in the accumulation of monosaccharides required for cell wall synthesis at the stage of cell thickening.

Amino Acid Sequence↗

PubMed2000

Sugar uptake and transport in rice embryo. Expression of companion cell-specific sucrose transporter (OsSUT1) induced by sugar and light.

We investigated sugar uptake and transport in rice (Oryza sativa) embryo during grain germination. Endogenous sugar levels, accumulation of starch granules, and gene expression of a rice sucrose transporter (OsSUT1) were examined using rice embryos germinated with or without exogenous sugar supply. Starch granules remarkably accumulated in the cells around vascular bundles as a consequence of the sugar taken up by the embryos, indicating that the taken-up sugars are transiently converted into starch. In situ detection for OsSUT1 mRNA indicated its localization in the phloem companion cells. Furthermore, northern-blot and in situ hybridization analyses showed that OsSUT1 expression is not detectable in embryos subjected to sugar starvation conditions, whereas its expression is enhanced by an increased endogenous sugar level. Overall results indicate that the expression of companion cell-specific sucrose transporter, OsSUT1 is regulated by the endogenous sugar status as well as light exposure.

Biological Transport↗

PubMed2000

Cloning and expression of a novel murine anti-human Fas antibody.

Agonistic anti-human Fas antibodies that can induce apoptosis are thought to have therapeutic effects for various diseases resulting from an abnormality of the Fas/FasL system. However, some anti-Fas antibodies show toxicity, and it is difficult to investigate their therapeutic and toxicological effect using animals because of their species specificity. We previously obtained a murine anti-human Fas mAb, HFE7A. HFE7A reacted with both human and murine Fas, and mitigated lymphadenopathy without any sign of hepatotoxicity in MRLgld/gld mice. It is suggested that humanized HFE7A would be a therapeutic treatment for various diseases resulting from an abnormality of the Fas/FasL system. Here we isolated the cDNAs that code for the heavy and light chains of HFE7A and identified the corresponding nucleotide sequences. The recombinant HFE7A was indistinguishable in binding and apoptosis-inducing activity to that from a hybridoma cell line. These data provide essential information for the humanization and clinical application of the humanized HFE7A.

Amino Acid Sequence↗

PubMed2000

[Risk factors and effect of reperfusion therapy on left ventricular free wall rupture following acute myocardial infarction].

Reperfusion therapy is one of the most effective treatments for acute myocardial infarction, but the effect on left ventricular free wall rupture remains to be determined. This study tried to clarify the risk factors and effect of reperfusion therapy on the risk of free wall rupture following acute myocardial infarction. 2,671 consecutive patients with acute myocardial infarction admitted to our hospital were examined. Incidence of free wall rupture showed no degenerative change(0 to 5.8%; mean 2.1%). The 1,269 consecutive patients from 1985 to 1995 were examined closely to evaluate risk factors and the effect of reperfusion therapy on the risk of free wall rupture. Fourteen patients who underwent emergent coronary artery bypass surgery were excluded. Free wall rupture was found in 25 patients (2.0%). Multivariate analysis confirmed that high age(> or = 70 years) and first acute myocardial infarction were independent risk factors of free wall rupture (odds ratio 3.62, p = 0.003; odds ratio 7.69, p = 0.046, respectively). The incidence of free wall rupture in the conservative therapy group(n = 799) was 2.1%, successful reperfusion group(n = 373) was 0.5%, and unsuccessful reperfusion group(n = 83) was 7.2% with significant statistical differences(p < 0.01). There was no statistical difference between the direct percutaneous transluminal coronary angioplasty group(n = 84, 3.6%) and the thrombolysis group(n = 372, 1.3%). Successful reperfusion was the only independent factor in the reperfusion therapy group that reduced the incidence of free wall rupture(odds ratio = 0.07, p = 0.001). We conclude that reperfusion of the infarct-related artery and more intensive management of unsuccessful reperfusion is important to prevent free wall rupture following acute myocardial infarction.

Age Factors↗

PubMed2000

Acetabular labrum in hip dysplasia evaluated by radial magnetic resonance imaging.

OBJECTIVE: To numerically express morphologic conditions and signal intensity in the acetabular labrum of the weight-bearing portion of hip joints in patients with hip dysplasia. METHODS: Using a radial magnetic resonance imaging (MRI) technique, where the planes are set radially centered on the midpoint of acetabulum, and which depicts the entire acetabular rim and acetabular labrum, we investigated 60 hip joints of 35 patients with hip dysplasia. RESULTS: The acetabular labrum was larger in dysplastic hips than in normal hips, and the size increased in the posterosuperior portion. All patients had portions with signal intensity changes within the labrum and had impairment on the labrum. When osteoarthrosis due to hip dysplasia was observed, signal intensity changes increased. The changes of intensity varied among the portions observed, and were stronger in the anterosuperior portions than in the superior and posterosuperior portions. CONCLUSION: Radial MRI numerically depicts morphologic conditions of acetabular labrum; the data were usable to evaluate the size difference in acetabular labrum due to hip dysplasia and the degree of impairment.

Acetabulum↗

PubMed2000

Multi-effective properties of homogentisic acid revealed in reactions with human hemoglobin and human erythrocytic hemoglobin.

Homogentisic acid (HGA) causes oxidation of human oxyhemoglobin and reduction of methemoglobin. The rate of oxidation of oxyhemoglobin by HGA is greatly accelerated in the presence of myo-inositol hexakis-phosphate (P6-inositol) or superoxide dismutase (SOD), but is inhibited in the presence of catalase. The reduction rate of methemoglobin by HGA is accelerated in the presence of P6-inositol but is greatly inhibited in the presence of SOD. It is suggested that the semiquinone and quinone form of HGA and oxygen radicals may be involved in the mechanism of oxido-reductive reactions of human hemoglobin with HGA. In addition, a new anodic hemoglobin found by isoelectric focusing electrophoresis was produced during the reaction of oxyhemoglobin with HGA. When human erythrocytes were exposed to HGA for several hours at 37 degrees C (pH 7.4), the anodic oxyhemoglobin (HGA-modified hemoglobin) and its half met-form hemoglobin [(alpha3+beta2+)2 of HGA-modified hemoglobin] were produced in significant amounts. HGA-modified hemoglobin was stably purified and showed increased oxygen affinity, absence of titratable sulfhydryl groups, and the absorption spectrum of normal oxyhemoglobin. Our results demonstrate that HGA shows multiple effects on human hemoglobin and erythrocytic hemoglobin, which is consistent with the evidence that HGA is involved in various pathological conditions such as arthritis and carcinogenesis in humans.

Erythrocytes↗

PubMed1999

Utility of postcolumn addition of 2-(2-methoxyethoxy)ethanol, a signal-enhancing modifier, for metabolite screening with liquid chromatography and negative ion electrospray ionization mass spectrometry.

A strategy for highly sensitive metabolite screening by liquid chromatography-electrospray ionization (ESI) mass spectrometry with the negative-ion mode that involves the use of a reversed-phase column in gradient-elution mode and postcolumn addition of 2-(2-methoxyethoxy)ethanol (2-MEE), a novel signal-enhancing modifier, has been described. When a mobile phase of 50 mM ammonium acetate/acetic acid buffer (pH 4.4) at a flow rate of 100 microL/min was employed, poor ESI response of ibuprofen as a model drug, probably due to both the high surface tension of the mobile phase and the ion-suppression effect of acetate anion in the mobile phase, was observed. On the other hand, the postcolumn addition of 2-MEE (50 microL/min) into the mobile phase counteracted the ion suppression as well as the surface tension problem, resulting in approximately 100-fold signal enhancement of the analyte. The metabolite screening of ibuprofen in human urine was subsequently carried out comparing the results with and without postcolumn addition of 2-MEE. The results indicated that the postcolumn addition of 2-MEE dramatically improved the ESI responses of all urinary metabolites detected without affecting the chromatographic separation.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1999

Ultrasensitive determination of NE-100, a novel sigma ligand, in human plasma by liquid chromatography and electrospray ionization tandem mass spectrometry combined with a column-switching technique.

For the highly sensitive and selective determination of NE-100, a novel sigma ligand, at levels of low picogram per milliliter of human plasma, a method with excellent reliability employing liquid chromatography (LC)-electrospray ionization (ESI) tandem mass spectrometry (MS-MS) combined with a column-switching technique has been developed. The method involves the use of a stable isotope labeled compound as the internal standard (I.S.), liquid-solid extraction of a plasma specimen with a C8 cartridge, automated on-line clean-up on a short trapping column, subsequent separation on a micro-bore C18 column and detection with ESI-MS-MS using m/z 356 ([M+H]+) as a precursor ion and m/z 105 as a product ion in a selected reaction monitoring mode. The detection and the quantification limits of NE-100 in plasma were 0.5 pg/ml with a signal-to-noise ratio (S/N) of 3 and 2.3 pg/ml, respectively, with an S/N of 21. The good linearity of the calibration graph was obtained in the range of 2.3 to approximately 907.0 pg/ml with excellent reliability. The developed method was applied to the determination of NE-100 in plasma obtained from the clinical trail.

Anisoles↗

PubMed1999

Therapist competence ratings in relation to clinical outcome in cognitive therapy of depression.

This study reports on the relationship of therapist competence to the outcome of cognitive-behavioral treatment in the National Institute of Mental Health Treatment of Depression Collaborative Research Program. Outpatients suffering from major depressive disorder were treated by cognitive-behavioral therapists at each of 3 U.S. sites using a format of 20 sessions in 16 weeks. Findings provide some support for the relationship of therapist competence (as measured by the Cognitive Therapy Scale) to reduction of depressive symptomatology when controlling for therapist adherence and facilitative conditions. The results are, however, not as strong or consistent as expected. The component of competence that was most highly related to outcome is a factor that reflects the therapist's ability to structure the treatment.

Adult↗