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Biomedical subjects

H Kaku

Publications and source records attributed to H Kaku.

At least 19 recordsLinked to original sources
PubMed2002

Analysis of HLA in children with gelatin allergy.

Systemic immediate reactions including anaphylaxis to gelatin in vaccines have been reported. However, the number of such reports is very small compared with the number of children exposed to gelatin. The present study was designed to investigate whether susceptibility or resistance to gelatin allergy is associated with human leukocyte antigen (HLA) class II gene. Blood samples were obtained from 49 patients with gelatin allergy and specific IgE to gelatin. DNA-based HLA class II typing was performed to determine the DRB1, DQB1 and DPB1 alleles. Genotype frequencies were compared with those found in 240 unrelated controls. The frequency of DQB1*0303 (55.1%) was significantly higher in the patients than in the control subjects (32.1%). The frequency of DPB1*0402 was also significantly higher in the patients (32.7%) than in the control subjects (15.4%). On the other hand, the frequency of subjects carrying DRB1*15 (DRB1*1501 and DRB1*1502) was significantly lower among the patients group (18.4%) than among the controls (40.8%). We found that DQB1*0303 and DPB1*0402 were positively associated with the IgE response for gelatin, while DRB1*15 was negatively associated with it.

Child↗
PubMed2002

Enhanced resistance to seed-transmitted bacterial diseases in transgenic rice plants overproducing an oat cell-wall-bound thionin.

Bacterial attack is a serious agricultural problem for growth of rice seedlings in the nursery and field. The thionins purified from seed and etiolated seedlings of barley are known to have antimicrobial activity against necrotrophic pathogens; however, we found that no endogenous rice thionin genes alone are enough for resistance to two major seed-transmitted phytopathogenic bacteria, Burkholderia plantarii and B. glumae, although rice thionin genes constitutively expressed in coleoptile, the target organ of the bacteria. Thus, we isolated thionin genes from oat, one of which was overexpressed in rice. When wild-type rice seed were germinated with these bacteria, all seedlings were wilted with severe blight. In the seedling infected with B. plantarii, bacterial staining was intensively marked around stomata and intercellular spaces. However, transgenic rice seedlings accumulating a high level of oat thionin in cell walls grew almost normally with bacterial staining only on the surface of stomata. These results indicate that the oat thionin effectively works in rice plants against bacterial attack.

Amino Acid Sequence↗
PubMed2001

Essential role of Stat5 for IL-5-dependent IgH switch recombination in mouse B cells.

IL-5 stimulation of CD38-activated murine splenic B cells induces mu-gamma1 CSR at the DNA level leading to a high level of IgG1 production. Further addition of IL-4 in the system enhances IL-5-dependent mu-gamma1 CSR. Although some of the postreceptor signaling events initiated by IL-5 in activated B cells have been characterized, the involvement of Stat in IL-5 signaling has not been thoroughly evaluated. In this study, we examined the activation of Stat5 and activation-induced cytidine deaminase (AID) in CD38-activated murine splenic B cells by IL-5. The role of Stat5a and Stat5b in IL-5-induced mu-gamma1 CSR and also IgG1 and IgM production was documented, as IL-5 does not act on CD38-stimulated splenic B cells from Stat5a(-/-) and Stat5b(-/-) mice. Expression levels of CD38-induced germline gamma1 transcripts and AID in Stat5a(-/-) and Stat5b(-/-) B cells upon IL-5 stimulation were comparable to those of wild-type B cells. The impaired mu-gamma1 CSR by Stat5b(-/-) B cells, but not by Stat5a(-/-) B cells, was rescued in part by IL-4, as the addition of IL-4 to the culture of CD38- and IL-5-stimulated B cells induced mu-gamma1 CSR leading to IgG1 production. Analysis of cell division cycle number of wild-type B cells revealed that mu-gamma1 CSR was observed after five or six cell divisions. Stat5a(-/-) and Stat5b(-/-) B cells showed similar cell division cycles, but they did not undergo mu-gamma1 CSR. Our data support the notion that both Stat5a and Stat5b are essential for IL-5-dependent mu;-gamma1 CSR and Ig secretion; however, their major target may not be AID. Stat5a and Stat5b are not redundant, but rather are at least partially distinctive in their function.

ADP-ribosyl Cyclase↗
PubMed2001

Construction and characterization of a Xanthomonas oryzae pv. oryzae bacterial artificial chromosome library.

Xanthomonas oryzae pv. oryzae is an important plant pathogen which causes bacterial blight of rice. To facilitate genome studies of this bacterium, we have constructed a bacterial artificial chromosome (BAC) library of strain MAFF 311018. It consisted of 750 clones representing 16 genome equivalents, and had an insert size ranging from 20 to 220 kb with an average size of 107 kb. This library is the first to be constructed from a X. oryzae pv. oryzae strain. The usefulness of this library was demonstrated through polymerase chain reaction screening of 11 genes and the 16S--23S rDNA spacer region in a 192-clone subset, representing five genome equivalents. The results obtained showed an average of 5.9 BAC clones per screening. This result is in good agreement with the estimated size of the test library, indicating that the constructed BAC library can be used to facilitate genome analysis of X. oryzae pv. oryzae.

Bacterial Proteins↗
PubMed2001

Second allogeneic peripheral blood stem cell transplantation with fludarabine-based low-intensity conditioning regimen for relapsed myelodysplastic syndrome after allogeneic bone marrow transplantation.

We describe the case of a 51-year-old patient with relapsed myelodysplastic syndrome after allogeneic bone marrow transplantation (BMT), who underwent allogeneic peripheral blood stem cell transplantation (PBSCT) after conditioning with a novel regimen consisting of fludarabine, busulfan, and antithymocyte globulin. The second PBSCT was performed early, at 3 months after the initial allogeneic BMT, but it was well tolerated and complete hematologic remission was documented. The patient did not experience any early transplantation-related organ toxicity but died from opportunistic infection 6 months after the second transplantation. Our experience suggests that this novel regimen may induce remission and could be offered to patients relapsing after the first transplantation; however, the fludarabine-containing regimen might be accompanied by profound immunosuppression.

Antineoplastic Agents↗
PubMed2001

Isolation and analysis of expression mechanisms of a rice gene, EL5, which shows structural similarity to ATL family from Arabidopsis, in response to N-acetylchitooligosaccharide elicitor.

Two rice cDNAs, EL5 and RRF1, were isolated and characterized. EL5 was responsive to N-acetylchitooligosaccharide, a biotic elicitor active in suspension-cultured rice cells. The structural specificity of the elicitor required for the expression of EL5 was consistent with other defense reactions observed in the experimental system, indicating that the elicitor signal to EL5 is transmitted through a single class of receptor-mediated recognition events. However, the intracellular signaling pathway to EL5 was distinct from those to other elicitor-responsive genes. Sequence analysis and alignment showed that a genomic sequence stored in rice genome databases in addition to EL5 and RRF1 belongs to the ATL family of RING-H2 finger motif proteins first isolated from Arabidopsis.

Journal Article↗
PubMed2001

Development of a routine analytical procedure for nonylphenol polyethyoxylates and their biodegradation products in sludge from sewage treatment plants.

A method of quantitative analysis of nonylphenol polyethoxylates (NPnEOs) and their biodegration products (NPE-BDPs) in sewage sludge, which is effective, economical, and applicable to a high performance liquid chromatography was developed and actual sludge samples collected from Japanese sewage treatment plants (STPs) were analyzed using the method to confirm its effectiveness. Soxhlet extraction showed better recovery in a spike and recovery test than shaking extraction. Among the four pretreatments for Soxhlet extraction tested, the condition in which samples were freeze-dried, ultrasonicated, and extracted with methanol showed the best recovery efficiency. Quantitative analysis of NPE-BDPs in STP sludge resulted in 6.1 microg/g, 4.3 microg/g, and 8. microg/g in average concentration for NPnEOs (n=1-3), NPnEOs (n=4-18), and nonylphenol ethoxycarboxylates (NPnECs (n=1-3)), respectively, and the values of concentration were 100-1000 times higher than those in effluent at Japan's STPs. The results implied importance of quantitation of NPE-BDPs in sewage sludge to assess the risk to the environment.

Biodegradation, Environmental↗
PubMed2000

Predictive markers for hepatic veno-occlusive disease after hematopoietic stem cell transplantation in adults: a prospective single center study.

Hepatic veno-occlusive disease (VOD) is a major complication after hematopoietic stem cell transplantation (HSCT). Aetiological determinants, diagnosis and treatment remain unclear. Changes in coagulation-fibrinolysis parameters and N-terminal propeptide for type III procollagen (P-III-P) have been studied in patients with or without VOD after HSCT. We prospectively measured protein C activity, tissue plasminogen activator (t-PA), antithrombin III (AT-III), plasminogen activity (PLG), thrombin-antithrombin III (TAT), alpha2-plasmin inhibitor (alpha2-PI),fibrinogen (Fbg) and P-III-P in 44 consecutive adult patients undergoing allogeneic HSCT. Each parameter was determined before conditioning, on day 0 of HSCT and weekly for 5 weeks. Five of the 44 patients developed VOD at a median post HSCT of day 3 (range, day 3 to 12). On repeated analysis of variance (ANOVA), there were significant differences between patients with and without VOD in P-III-P (P < 0.0001), protein C (P < 0.0001), t-PA (P < 0.0001), PLG (P < 0.0001), AT-III(P < 0.0001), Fbg (P < 0.0001), alpha2-PI (P = 0.0002). Levels of P-III-P were significantly higher in patients with VOD than without VOD, before preparative chemotherapy (P < 0.005) and on days 0 and 7 (P < 0.001). On day 0, levels of t-PA were significantly higher in patients with VOD than without VOD (P < 0.05). On day 7, levels of protein C were significantly lower in patients with VOD than without VOD (P < 0.01). On day 0, there were trends of differences (P = 0.0515) between patients with and without VOD in the levels of protein C. These results suggest P-III-P, t-PA and protein C are predictive markers for VOD after HSCT in adults. Moreover, the serum P-III-P level before start of conditioning might indicate patients at risk for developing VOD.

Adolescent↗
PubMed2000

A lipochito-oligosaccharide, Nod factor, induces transient calcium influx in soybean suspension-cultured cells.

Lipochito-oligosaccharides (Nod factors) produced by Rhizobium or Bradyrhizobium are the key signal molecules for eliciting nodulation in their corresponding host legumes. To elucidate the signal transduction events mediated by Nod factors, we investigated the effects of Nod factors on the cytosolic [Ca2+] of protoplasts prepared from roots and suspension-cultured cells of soybean (Glycine max and G. soja) using a fluorescent Ca2+ indicator, Fura-PE3. NodBj-V (C18:1, MeFuc), which is a major component of Nod factors produced by Bradyrhizobium japonicum, induces transient elevation of cytosolic [Ca2+] in the cells of soybean within a few minutes. This effect is specific to soybean cells and was not observed in the tobacco BY-2 cells. Furthermore, NodBj-V without MeFuc did not induce any cytosolic [Ca2+] elevation in soybean cells. Exclusion of Ca2+ from the medium, as well as pre-treatment of the cells with an external Ca2+ chelator or with a plasma membrane voltage-dependent Ca2+ channel inhibitor, suppressed the Nod factor-dependent cytosolic [Ca2+] elevation. These results indicate that transient Ca2+ influx from extracellular fluid is one of the earliest responses of soybean cells to NodBj-V (C18:1, MeFuc) in a host-specific manner.

Bradyrhizobium↗
PubMed2000

Herpes zoster in immunocompetent and immunocompromised Japanese children.

BACKGROUND: To confirm epidemiological features of herpes zoster among children with or without immunosuppression, herpes zoster patients who had presented to this hospital were retrospectively investigated. METHODS: Medical records were reviewed for the 92 cases of pediatric herpes zoster patients diagnosed during the period from 1981 to 1998. The age at onset of herpes zoster and of varicella, the interval between varicella and zoster, the dermatomal distribution of herpes zoster and complications were compared between immunocompetent and immunocompromised children. RESULTS: The mean age at onset of zoster in immunocompetent children was 8.5 +/- 4.0 years and in immunosuppressed children was 9.7 +/- 3.8 years. The age at onset of varicella was significantly lower (1.6 +/- 1.8 years) in immunocompetent than in immunosuppressed children (4.6 +/- 2.7 years). The interval between varicella and zoster was 6.2 +/- 3.2 years in immunocompetent children. More than 80% of patients with acute leukemia or malignant lymphoma had herpes zoster within 2 years after diagnosis of malignancy. Lesions of herpes zoster were most frequently found in the thoracic nerve regions. Five of 11 zoster patients with cutaneous dissemination, three of five zoster patients having aseptic meningitis and three of four patients complicated facial palsy were children without underlying disease. CONCLUSIONS: The present study confirmed that varicella in the first year of life was a risk factor in immunocompetent children, as reported previously. Herpes zoster in children without immunosuppression was found not to be as mild as generally accepted.

Age of Onset↗
PubMed2000

Induced expression of sarcotoxin IA enhanced host resistance against both bacterial and fungal pathogens in transgenic tobacco.

We demonstrate here that induced expression of sarcotoxin IA, a bactericidal peptide from Sarcophaga peregrina, enhanced the resistance of transgenic tobacco plants to both bacterial and fungal pathogens. The peptide was produced with a modified PR1a promoter, which is further activated by salicylic acid treatment and necrotic lesion formation by pathogen infection. Host resistance to infection of bacteria Erwinia carotovora subsp. carotovora and Pseudomonas syringae pv. tabaci was shown to be dependent on the amounts of sarcotoxin IA expressed. Since we found antifungal activity of the peptide in vitro, transgenic seedlings were also inoculated with fungal pathogens Rhizoctonia solani and Pythium aphanidermatum. Transgenic plants expressing higher levels of sarcotoxin were able to withstand fungal infection and remained healthy even after 4 weeks, while control plants were dead by fungal infection after 2 weeks.

Anti-Bacterial Agents↗
PubMed2000

[A retrospective study of the length of hospitalization following allogeneic bone marrow transplantation].

To estimate the length of hospitalization following bone marrow transplantation(BMT), we conducted a retrospective study of 190 patients who had received allogeneic BMTs at our institution. By our criteria, patients were considered ready for discharge if they were afebrile, did not need intravenous chemotherapy or blood transfusions more than 2 times per week, had maintained these conditions for 1 week or more, and also had no medical history of hepatic veno-occlusive disease, grade-II-or-higher graft-versus-host disease, interstitial pneumonitis, or severe hepato-renal dysfunction. The median length of hospitalization was 108.5 days. Of 82 patients who satisfied our discharge criteria by their 70th hospital day, 10 experienced mild complications during the next 30 hospital days. Of 89 patients who were considered ready for discharge by the 40th hospital day, 30 and 38 experienced complications during the next 30 and 60 hospital days, respectively, and 16 required emergency treatment. No significant baseline characteristics distinguished the patients who experienced complications from those who did not, either after 40 or 70 hospital days. This compounded the difficulty of predicting the development of complications in patients who satisfied our discharge criteria. Although management on an outpatient basis should be safe and feasible for BMT patients who meet our discharge criteria by the 70th day of hospitalization, caution is advised for early discharges after only 40 hospital days.

Adolescent↗
PubMed1999

Enhanced resistance to bacterial diseases of transgenic tobacco plants overexpressing sarcotoxin IA, a bactericidal peptide of insect.

Sarcotoxin IA is a bactericidal peptide of 39 amino acids found in the common flesh fly, Sarcophaga peregrina. Many agronomically important bacteria in Japan are killed by this peptide at sub-micro molar levels, and the growth of tobacco and rice suspension cultured cells is not inhibited with less than 25 microM. Transgenic tobacco plants which overexpress the peptide, i.e. over 250 pmol per gram of fresh leaf, under the control of a high expression constitutive promoter showed enhanced resistance to the pathogens for wild fire disease (Pseudomonas syringae pv. tabaci) and bacterial soft rot disease (Erwinia carotovora subsp. carotovora).

Animals↗
PubMed1998

A cell wall-bound beta-glucosidase from germinated rice: purification and properties.

A large portion of beta-glucosidase (EC 3.2.1.21) in germinating rice seeds, which appears to be ionically bound to cell walls, can be solubilized with 1 M NaCl. Its activity increased more than eight-fold within five days of germination. It was purified to electrophoretic homogeneity from the extracts of germinated rice seeds by fractionation with (NH4)2SO4 followed by CM-Sepharose, Polybuffer exchanger 118, Concanavalin A-Sepharose and Bio-Gel P-100. The Mr of the purified enzyme, estimated by SDS-PAGE, was 56,000 and the isoelectric point was > 10.0. Its N-terminal amino acid sequence (44 residues) exhibited high homology to those of beta-glucosidases from other plants, such as barley and white clover. Its activity was optimal at pH 4.5 and 50 degrees, and it was strongly inhibited by glucono-1,5-lactone. The enzyme showed hydrolytic as well as transglycosylation activity towards (1-->3)-beta- and (1-->4)-beta-linked oligosaccharides with degree of polymerization of 2-4. The results suggest that the beta-glucosidase is probably involved not only in hydrolysis but also in modification of oligosaccharides in cell walls of germinating rice seeds.

Amino Acid Sequence↗
PubMed1998

Vertical infection of human immunodeficiency virus as an imported infectious disease.

BACKGROUND AND METHODS: In Japan, 26 children who vertically acquired human immunodeficiency virus (HIV) infection had been reported as at February 1997. Little information was published about their epidemiological backgrounds and the rate of perinatal HIV transmission in Japan remains unknown. To learn the epidemiological features of perinatal HIV infection in Japan, we examined the medical records of five perinatally infected children. RESULTS: Three of five mothers were Japanese and two others were South East Asian. Four of them acquired HIV infection abroad and one became infected through her spouse who had acquired infection abroad. Therefore, HIV infection in these five cases can be regarded as an imported infectious disease. None of the five mothers noticed their HIV infection before their pregnancy. One mother was found to be HIV seropositive during her pregnancy, but the others did not notice their HIV infection until their delivery. CONCLUSIONS: To reduce the incidence of perinatally HIV-infected children it is necessary to lower the incidence of mother-to-infant HIV transmission. In Western countries they have succeeded in reducing the risk for perinatal HIV transmission with perinatal zidovudine therapy. To prescribe the preventive therapy against perinatal HIV transmission, it is essential to know if pregnant women are infected with HIV or not. Therefore, women of childbearing age should accept voluntary prenatal HIV testing. At the same time, they should be offered such programs that can enable them to receive timely counseling, besides medical treatment, if they are found to be HIV infected.

Emigration and Immigration↗
PubMed1998

Altered calcium handling in compensated hypertrophied rat cardiomyocytes induced by pressure overload.

To investigate Ca2+ handling in compensated hypertrophied cardiomyocytes, we measured Ca2+ transients and contraction of hypertrophied rat left ventricular myocytes induced by aortic constriction (AC). The fluorescence ratio (I405/I480) after indo-1/AM loading and circumferential length were simultaneously measured in isolated myocytes. The amplitude of Ca2+ transients (Ca-Amp) was higher in rats with AC than in sham-operated rats (Sham) (0.25 +/- 0.08 vs 0.17 +/- 0.05). There was a positive correlation between Ca-Amp and fractional shortening (FS) in both AC and Sham rats, whereas the ratio of FS/Ca-Amp was smaller in AC rats. These observations suggest that compensated hypertrophied cardiomyocytes exhibit an adaptive increase in Ca-Amp, associated with reduced myofilament responsiveness to an increase in Ca2+. Isoproterenol and forskolin increased Ca-Amp and FS, and decreased time to 50% decline of Ca2+ transients. Although myocytes from AC rats exhibited reduced responsiveness to isoproterenol, responses to forskolin did not differ between the 2 groups. The reduced beta-adrenergic response in Ca2+ handling was probably due to altered beta-adrenoceptor numbers, G-protein function and/or their coupling process.

Adrenergic beta-Agonists↗