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T Takasaki

Publications and source records attributed to T Takasaki.

At least 19 recordsLinked to original sources
PubMed2007

Detection of antibodies to Japanese encephalitis virus in the wild boars in Hiroshima prefecture, Japan.

Serum specimens were collected from 25 wild boars in Hiroshima prefecture located in the western region of Japan from November 2004 to February 2005. The sera were tested for antibodies to Japanese encephalitis virus (JEV) by IgM capture and IgG enzyme-linked immunosorbent assays (ELISA), and plaque reduction neutralization test. Seventeen samples (68%) were positive for neutralizing antibody to JEV. All the neutralizing antibody-positive samples were positive for IgG-ELISA. One was also positive for IgM. The results indicate that approximately 70% of the wild boars were positive for anti-JEV antibody, and raises the possibility that wild boars may play a role in the infectious cycle of JEV in this region.

Animals↗
PubMed2006

cDNA cloning of nine S alleles and establishment of a PCR-RFLP system for genotyping European pear cultivars.

Nine full-length cDNAs of S ribonucleases (S-RNases) were cloned from stylar RNA of European pear cultivars by RT-PCR and 3' and 5' RACE. Comparison of the nucleotide sequences between the nine S-RNases cloned and 13 putative S alleles previously amplified by genomic PCRs revealed that seven corresponded to Sa, Sb, Sd, Se, Sh, Sk and Sl alleles, and the other two were new S alleles (designated as Sq and Sr alleles). Genomic PCR with a set of a8FTQQYQa9 and a8EP-anti-IIWPNVa9 primers was used to amplify nine S alleles; 1,414 bp (Sl), ca. 1.3 kb (Sk and Sq), 998 bp (Se), 440 bp (Sb) and ca. 350 bp (Sa, Sd, Sh and Sr). Among these, S alleles of similar size were discriminated by digestion with BaeI, BglII, BssHII, HindIII, EcoO109I and SphI. The PCR amplification of S allele following digestion with the restriction enzymes provided a PCR-RFLP system for rapid S-genotyping European pear cultivars harboring nine S alleles. The PCR-RFLP system assigned a total of 63 European pear cultivars to 25 genotypes. Among these, 14 genotypes were shared by two or more cultivars, which were cross-incompatible. These results suggested that the genes cloned represented the S-RNases from European pear, and that there were many cross-incompatible combinations among European pear varieties.

Alleles↗
PubMed2003

Involvement of the JNK-like protein of the Aedes albopictus mosquito cell line, C6/36, in phagocytosis, endocytosis and infection of West Nile virus.

We recently cloned a c-Jun amino-terminal kinase (JNK) sequence from the C6/36 cell line, derived from the mosquito Aedes albopictus. We showed that SP600125, an inhibitor of JNK proteins, inhibits phagocytosis by C6/36 cells, suggesting that the JNK-like protein regulates phagocytosis. Here, we show that C6/36 cells constitutively express low levels of mRNA encoding the antibacterial peptides, cecropin and defensin, but that these mRNAs were up-regulated upon stimulation by lipopolysaccharide (LPS). Thus, the C6/36 cells have properties similar to those of mammalian macrophages. To characterize further the functional properties of C6/36 cells, we have assayed the role of the JNK-like protein in phagocytosis, endocytosis, and viral infection. C6/36 cells phagocytosed bacteria and artificial beads, and this was only slightly up-regulated following LPS stimulation, suggesting that newly stimulated JNK-like protein was not necessary for phagocytosis. SP600125 inhibited the acidification of intracellular compartments, including those involved in the endocytic pathway. Pretreatment of C6/36 cells with SP600125 or bafilomycin A1, but not cytochalasin D, inhibited the entry of West Nile virus (WNV), suggesting that WNV is internalized mainly by endocytosis, and that the JNK signalling pathway is important for endocytic entry. These findings indicate that the JNK-like protein regulates basic physiological functions, including phagocytosis and endocytosis and infection of WNV.

Aedes↗
PubMed2003

[Preoperative autologous blood donation with cardiac surgery].

BACKGROUND: Preoperative autologous blood donation is commonly used to reduce exposure to homologous blood transfusions among patients undergoing elective cardiac surgery. The purpose of this study was to ascertain how much volume of predonated autologous blood need to avoid of homologous blood transfusion in cardiac procedure. METHODS: One hundred twenty-eight patients underwent scheduled cardiac procedure between January 1998 and December 1999. Group 1: 400 ml predonated, operation without cardiopulmonary bypass (CPB) [n = 33], group 2: 800 ml predonated, operation without CPB (n = 23), group 3: 800 ml predonated, operation with CPB (n = 36), group 4: 1,200 ml predonated, operation with CPB (n = 36). Surgical procedures underwent only off-pump coronary artery bypass grafting (OPCAB) in groups 1 and 2. In groups 3 and 4 included coronary artery bypass grafting (CABG), valve replacement, CABG + valve replacement and atrial septal defect repair. RESULTS: There were no significant differences in mean body weight, mean preoperative hematocrit values or mean volume of intraoperative blood loss between groups 1 and 2. There were no significant differences in mean age, mean body weight, mean preoperative and postoperative day-7 hematocrit values, mean volume of intraoperative blood loss or mean CPB time between groups 3 and 4. The mean postoperative day-7 hematocrit value was significantly lower in group 1 than in group 2. Homologous blood transfusion was avoided in 63.6% of those with predonation of group 1 versus 100% at group 2 (p < 0.05), 86.1% at group 3 versus 94.4% at group 4 (p < 0.05). In group 3, all patients who underwent redo operation or CABG + valve replacement needed homologous blood transfusion. CONCLUSIONS: Autologous blood transfusion is effective for reducing the homologous blood requirement. It also seems that predonation of 800 ml may be sufficient to avoid homologous blood transfusion in cardiac surgery, however predonation of 1,200 ml is desirable in cases of redo operation or CABG + valve replacement.

Aged↗
PubMed2002

Mitral valve replacement in ischemic mitral regurgitation. Preservation of both anterior and posterior mitral leaflets.

BACKGROUND: The surgical risks associated with ischemic mitral regurgitation are thought to be greater than those for other forms of mitral regurgitation. We have performed mitral valve replacement using the St. Jude Medical bileaflet prostheses with preservation of both leaflets, along with all of the chordae tendineae and papillary muscles. The aim of this study was to retrospectively evaluate mitral valve replacement with preservation of both mitral valves with respect to long-term clinical results and left ventricular performance. METHODS: Between January 1, 1988 and February 29, 2000, 15 patients were operated on for ischemic mitral regurgitation. There were 7 males and 8 females, and the mean age was 69.7+/-8.1 years. The preoperative variables showed clinical deterioration of the state, such as emergency operation in 40% of the patients, more than NYHA functional III class in 93% of patients, cardiogenic shock in 47% of the patients, a mean left ventricular ejection fraction of 36.8%, and a mean left ventricular end-systolic volume index of 116.7 ml/m2. RESULTS: There were 5 (33.3%) hospital deaths during the follow-up period including 1 early death and 1 (10%) late death during the follow-up period. Thus, the actuarial survival rate after 5 years for the whole was 60%. However, the left ventricular dimensions and left ventricular fractional shortening, even if in patients with profound depressed left ventricular function preoperatively, showed maintenance of the cardiac function. CONCLUSIONS: These results suggested that mitral valve replacement using the St. Jude Medical prostheses with preservation of both leaflets and all chordae tendineae and papillary muscles might be a procedure of choice for ischemic mitral regurgitation.

Aged↗
PubMed2001

Genetic characterization and geographic distribution of rabies virus isolates in Brazil: identification of two reservoirs, dogs and vampire bats.

We analyzed 50 rabies virus samples isolated in Brazil from 12 dogs, 11 cats, 5 vampire bats, 15 cattle, 2 horses, 1 pig, 1 sheep, and 3 humans to investigate the molecular epidemiology of rabies viruses. We sequenced 203 nucleotides on the nucleoprotein gene by direct sequencing of the PCR-amplified products. All the isolates belonged to the genotype 1 and homology of the 203 nucleotides was at least 83.7% among isolates. The main reservoirs were estimated based on the homology of nucleotide sequences. Brazilian rabies virus isolates were clustered into two reservoir groups: dogs and vampire bats. All the dog-related rabies virus isolates showed nucleotide homology greater than 99.0%. Vampire bat-related rabies virus isolates showed nucleotide homology greater than 96.6% and could be further divided into subgroups corresponding to areas where viruses were isolated. These data suggest that circulating rabies variants belong to at least two different genotype clusters in Brazil and that these two clusters are maintained independently among vampire bats and dogs.

Amino Acid Sequence↗
PubMed2001

Ascending aorta dissection associated with bicuspid aortic valve. Considerations 4 years after combined coronary artery bypass grafting and mitral valve replacement.

Aortic dissection etiology involve many factors that are difficult to identify clearly. We report a 47-year-old man who underwent a Bentall operation with reattachment of bypass grafts for a dissecting aneurysm (DeBakey type II) 4 years after combined triple coronary artery bypass grafting and mitral valve replacement. This case appeared to be associated with factors leading to dissecting aneurysm although it remains unclear which was more influential congenital bicuspid aortic valve or proximal anastomosis of venous grafts or both. This case suggests the need to consider appropriate timing in surgical intervention for cases of congenital bicuspid aortic valves and the selection of additional aortic valve replacement in initial surgery.

Aortic Dissection↗
PubMed2001

Development of dengue IgM-capture enzyme-linked immunosorbent assay with higher sensitivity using monoclonal detection antibody.

An IgM-capture enzyme-linked immunosorbent assay (IgM-ELISA) is used widely for serodiagnosis of dengue. A dengue IgM-ELISA with higher sensitivity has been developed. In the new ELISA, anti-dengue IgM antibody, which had been captured on the solid phase, was reacted with tetravalent dengue viral antigens, and detected by a flavivirus group specific monoclonal antibody, D1-4G2-4-15 (4G2). Reaction of 4G2 to viral antigens was similar to that of dengue patients' IgG. Non-specific reaction of 4G2 to the control antigen, which was prepared from uninfected cell culture fluid of mosquito C6/36 cells, was much lower than that of patients' IgG. Thus, specificity of the ELISA with 4G2 was much higher than that with patients' IgG, and lower levels of specific IgM was detected in the serum samples. These results suggest that the modified dengue IgM-ELISA with monoclonal antibody 4G2 has many advantages over the original "in-house" ELISA.

Antibodies, Monoclonal↗
PubMed2001

The S receptor kinase gene determines dominance relationships in stigma expression of self-incompatibility in Brassica.

Self-incompatibility (SI) in Brassica is sporophytically controlled by the multi-allelic S locus. SI phenotypes of the stigma and pollen in an S heterozygote are determined by the two S haplotypes it carries; the two haplotypes may be co-dominant or exhibit a dominant/recessive relationship. Because the S receptor kinase (SRK) gene of the S locus was recently shown to determine the S haplotype specificity of the stigma, we wished to investigate whether SRK also plays a role in the dominance relationships between S haplotypes. We crossed plants carrying an SRK28 transgene with plants homozygous for one of five S haplotypes that are either co-dominant with, or recessive to, S28 haplotype in the stigma, and analyzed the SI phenotypes of the progeny. In all cases, the SI phenotype of the stigma of plants carrying the SRK28 transgene could be predicted by the known dominance relationships between the S haplotype(s) and the S28 haplotype. Moreover, in the S43 homozygote carrying the SRK28 transgene where the S43 phenotype in the stigma was masked by the presence of the SRK28, the transcript level of SRK28 was found to be much lower than that of SRK43. All these results suggest that the dominance relationships between S haplotypes in the stigma are determined by SRK, but not by virtue of its relative expression level.

Blotting, Northern↗
PubMed2001

Electron microscopic study of persistent dengue virus infection: analysis using a cell line persistently infected with Dengue-2 virus.

We investigated persistent infection of Epstein-Barr virus (EBV)-transformed lymphoblastoid cells with dengue virus using a transmission electron microscope. Most of the infected cells kept an intact morphology with only a few virus particles in the cytoplasm, but without any indication of active viral replication. Some cells were apoptotic and a few dengue virus particles were present in these apoptotic cells. Raji cells acutely infected with dengue-2 virus showed degenerative morphology. There were membranous tubular structures and many virus particles around and within the infected cells. Approximately 95% of the cells were dengue viral antigen positive in the persistently infected EBV-transformed cell line. It is likely that persistent infection is maintained mainly by the division of infected cells without cytopathic effect by dengue-2 virus.

Antigens, Viral↗
PubMed2001

Detection of rabies virus RNA isolated from several species of animals in Brazil by RT-PCR.

Brain samples from different animal species including humans: five vampire bats, 14 cattle, 12 dogs, 11 cats, two horses, one pig, one sheep and three humans collected from various geographical regions of Brazil were found to be positive for rabies by means of the fluorescent antibody test (FAT) and the mouse inoculation test (MIT). The brain samples were retested for rabies by means of the reverse transcription and polymerase chain reaction (RT-PCR) with 2 primer sets (P1/P2 and RHNI/RHNS3), which amplified full or partial regions on the nucleoprotein (N) gene of the rabies virus, respectively. Brain samples from five vampire bats, 13 cattle, one horse and one sheep failed to yield PCR products when the RHN1/RHNS3 primer pair was used, but all brain samples successfully yielded the products when the P1/P2 primer pair was used. These results suggest that Brazilian rabies virus isolates could be principally divided into two populations according to genetic difference.

Animals↗
PubMed2001

[Preoperative autologous blood donation in elderly patients with cardiovascular surgery].

BACKGROUND: During the cardiovascular surgeries in elderly people, only a few cases can avoid the homologous blood transfusion, because of their preoperative anemic tendency and low hemopoietic abilities. We examined the capability to avoid the homologous blood transfusion in over 75 year old patients by the preoperative autologous blood collection. Sixty-six patients underwent scheduled cardiovascular surgery between January 1996 and December 1999. The groups were divided into three categories of preoperatively collected autologous blood amounts: high-amount (800-1,200 ml), medium-amount (200-800 ml), and low-amount (0 ml). Each group was divided into two subgroups in according to the use of cardiopulmonary bypass (CPB). There were no differences among the each group in age, body weight, or preoperative and postoperative day-7 hematocrit values. RESULTS: Only 21.2% of patients could donate the expected blood amounts preoperatively. Mean volume was 641 ml. In groups used CPB, no patient was transfused homologous blood in high-amount group. On the contrary, 100% patients were donated in medium and low amount groups. In groups operated without CPB, homologous blood transfusion was required 14.3% in high-amount group, 25.0% in medium-amount group, and 83.3% in low-amount group. CONCLUSION: It seems that predonation of more than 800 ml may be sufficient to avoid the homologous blood transfusion in using CPB operation and more than 400 ml in non using CPB operation.

Aged↗
PubMed2001

[A case of thrombosed St. Jude Medical valve 16 years after initial mitral valve replacement].

We report successful surgery for a thrombosed St. Jude Medical (SJM) valve 16 years after the initial mitral valve replacement even under conditions of satisfactory anticoagulation therapy. A 61-year-old-female had intermittent claudication and was admitted to our hospital for examination. The prosthetic valve sounds were normal to auscultation and the left ankle-pressure index was decreased to 0.6. Transthoracic echocardiography revealed no mitral regurgitation and a mean mitral valve gradient of 6-7 mmHg. Furthermore, transesophageal echocardiography revealed that one of the leaflets of the prosthetic valve was entirely immobilized at the closing position and a mobile soft tissue mass, 5 mm in diameter, was detected at the atrial side of the obstructed leaflet. Although 96,0000 IU of urokinase was administered intravenously for a week, we could not confirm any change in leaflet mobility. At the time of surgery, the posterior leaflet of the SJM valve, which was implanted at an anatomical orientation, was obstructed at the closing position with old and fresh thrombi. We decided upon replacement with a CarboMedics 29 M prosthetic valve. Postoperative medication consisted of warfarin plus low-dose aspirin. Generally, valve thrombosis occurs within 5 years after valve replacement. However, valve thrombosis is possible even in a reliable SJM valve and as long as 16 years after replacement. Therefore, the implantation of an SJM valve at an anti-anatomical orientation might lower the incidence of valve thrombosis in addition to life-long anticoagulation therapy.

Female↗
PubMed2001

Increase in the sensitivity of dengue diagnosis by combination of reverse transcriptase-polymerase chain reaction and passage on cell cultures.

We passaged 52 serum samples from dengue patients on C6/36 cells for 7 days and checked the culture fluids by RT-PCR. Two serum samples, which were negative by direct RT-PCR, became positive. One sample was collected on fever day 1 and the other on fever day 2. Results indicate that combination of reverse transcriptase-polymerase chain reaction (RT-PCR) with passage of serum samples on C6/36 cells increases the sensitivity of dengue diagnosis.

Cell Line↗
PubMed2000

Immunogenicity and protective efficacy of the current inactivated Japanese encephalitis vaccine against different Japanese encephalitis virus strains.

Mouse brain-derived, inactivated Japanese encephalitis (JE) vaccine has been internationally used for many years. It is believed that this vaccine made a great contribution to the reduction of JE patients in several countries. Mouse brain-derived, Beijing-1 and Nakayama JE vaccines induce high levels of neutralizing antibodies. High levels of induced antibodies are maintained at least for 3-4 yr. The induced antibodies are cross-reactive to heterologous strains; however, the neutralizing antibody titers against heterologous strains are usually lower than those against homologous strains. Considering that both Nakayama and Beijing-1 JE vaccines showed high levels of protective efficacy in Taiwan and Thailand where strains other than Nakayama and Beijing-1 were circulating, we conclude that the current inactivated JE vaccine can induce high levels of protective immunity against heterologous JE virus strains.

Animals↗