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Biomedical subjects

T Horii

Publications and source records attributed to T Horii.

At least 91 records · Page 5Linked to original sources
PubMed1997

Plasmodium falciparum: an epitope within a highly conserved region of the 47-kDa amino-terminal domain of the serine repeat antigen is a target of parasite-inhibitory antibodies.

Previously, the Plasmodium falciparum serine repeat antigen has been shown to be protective in primate models of malaria immunity and also to be a target of in vitro parasite-inhibitory antibodies. To further define parasite-inhibitory epitopes a series of deletions from the amino-terminal 47-kDa domain of the serine repeat antigen (SERA) were constructed as glutathione-S-transferase fusion proteins. Several GST-SERA fusion proteins were used to vaccinate mice with Freund's adjuvant and the resulting immune sera were used to assay for the inhibition of P. falciparum invasion of erythrocytes in vitro. The minimal epitope shown to be the target of invasion-blocking antibodies was SERA amino acids 17-165. Additional GST-SERA deletion constructs of the 47-kDa domain were developed and evaluated for reactivity, by Western immunoblot analysis, with a parasite-inhibitory murine monoclonal antibody (mAb 43E5), a parasite-inhibitory pooled goat polyclonal sera, and a pooled human Nigerian immune serum. The parasite-inhibitory epitope defined by mAb 43E5 was mapped to SERA amino acids 17-110 and, at least, part of the epitope was defined to include amino acids in the region of amino acids 59-72. The parasite-inhibitory epitope recognized by mAb 43E5 appears to be well conserved between diverse geographical isolates of P. falciparum. The results have relevance for malaria vaccine development and suggest that an appropriately designed recombinant SERA antigen produced from a synthetic gene in Escherichia coli may be an effective component of a candidate malaria vaccine.

Amino Acid Sequence↗
PubMed1997

Semiskeletonization of internal thoracic artery: alternative harvest technique.

A simple technique of harvesting the internal thoracic artery is described. Harvesting the internal thoracic artery as a thin pedicle without the endothoracic fascia is advantageous in terms of obtaining its maximum length, dissecting a narrow space, avoiding pleural opening, and facilitating handling of the internal thoracic artery during the coronary anastomoses. This alternative-technique requires almost the same skill and time as the conventional wide pedicle technique.

Humans↗
PubMed1997

RobA-induced multiple antibiotic resistance largely depends on the activation of the AcrAB efflux.

RobA is a member of the XylS/AraC subfamily of DNA binding proteins, and when overexpressed, it induces multiple antibiotic resistance in Escherichia coli. In this study, we introduced a multicopy robA plasmid (pMEP1) and its derivative into OmpF mutants and an AcrAB-deficient mutant. We found that a decrease in susceptibility to multiple antibiotics in these OmpF mutants when pMEP1 was introduced did not depend on OmpF porin expression. Interestingly, a delta ompF mutant (TK007) became more sensitive when pMEP1 was introduced. Moreover, no effect of RobA on the induction of multiple antibiotic resistance in an acrA1- mutant was observed. Therefore, we conclude that the multiple antibiotic resistance induced by the overexpression of RobA largely depends on the activation of the AcrAB efflux, as well as the activation of micF.

Bacterial Proteins↗
PubMed1997

Immunodiagnosis of alveolar echinococcosis by enzyme-linked immunosorbent assay using a partially purified Em18/16 enriched fraction.

An improved enzyme-linked immunosorbent assay (ELISA) system using partially purified Eml8/16 enriched fraction (PP-Em18/16) prepared by isoelectric focusing was evaluated for serodiagnosis of alveolar echinococcosis (AE). The PP-Em18/16-ELISA was compared with Em2plus-ELISA by using sera from AE and cystic echinococcosis (CE) patients in China, where both AE and CE are endemic; sera from CE patients in Australia, where only CE exists; and sera from patients with cysticercosis, paragonimiasis, or sparganosis in Korea, where no indigenous AE or CE exists. We used Em2plus-ELISA as a standard ELISA and found 24.6% (17 of 69 specimens) cross-reactivity with sera from CE. Furthermore, some of the sera from paragonimiasis, sparganosis, and cysticercosis patients were also cross-reactive in the Em2plus-ELISA. When we tested for similar cross-reactivity in the same sera from CE patients by PP-Em18/16-ELISA (23.2%, 16 of 69), it became evident that the specificity of the PP-Em18/16-ELISA was better than that of the Em2plus-ELISA, since no sera from patients with the examined parasitic diseases except CE showed cross-reactivity. Some CE patients from China showed exceptionally high levels of antibody in comparison with those of CE patients from Australia, where no AE occurs. It is speculated that these patients with strongly positive cases of CE from China may have been exposed to both species of Echinococcus.

Animals↗
PubMed1997

Antibody responses against Em18 and Em16 serodiagnostic markers in alveolar and cystic echinococcosis patients from northwest China.

Western blot analysis was carried out in order to evaluate new serodiagnostic markers, Em18 and Em16, for differentiation of alveolar echinococcosis (AE) from cystic echinococcosis (CE) using 36 serum samples from hydatid patients from Xinjiang, China, where AE and CE are both endemic and one double infection case has been reported. All AE cases except one (5/6) who exhibited a calcified lesion and a single case of double infection showed antibody responses against Em18 and Em16. Some of CE patient sera (6/22) showed antibody response against Em16 except one who showed that against Em18. Analyses of IgG subclass responses against Em18 and Em16 were carried out using all serum samples showing antibody responses against Em18 and/or Em16 (seven CE, five AE, and one AE + CE) and additional samples of three CE and 22 AE from Sichuan, China. IgG4 was the most predominant antibody subclass. Em18 and Em16 were recognized by both IgG4 and IgG1 (in most cases) or by either IgG4 or IgG1 (in minor cases) or by IgG3 (in very rare cases). Neither Em18 nor Em16 was recognized by IgG2 antibodies. The usefulness of Em18 and Em16 as potential new markers for serological differentiation of human AE and CE, respectively, is discussed.

Antibody Formation↗
PubMed1997

[New surgical procedure for patients with dilated heart and end-stage cardiac failure (Batista procedure)].

A 53-year-old man with dilated cardiomyopathy underwent left ventriculoplasty (Batista procedure), a new surgical procedure, which reduces ventricular volume to improve left ventricular function. Left ventricular ejection fraction increased from 19.7% to 43.7%. Unfortunately, he died of pneumonia 12 days after surgery. This is the first such procedure in a human in Japan.

Cardiac Surgical Procedures↗
PubMed1997

Left ventriculoplasty: a new option for end-stage cardiomyopathy.

To treat end-stage dilated cardiomyopathy, we have performed volume reduction left ventriculoplasty (as introduced by Randas Batista in Brazil) in four patients since December 1996. All patients had end-stage idiopathic cardiomyopathy. Mitral valve replacement was also performed in three patients. In all four patients, improvement of left ventricular function was noted. One patient died of respiratory failure on the 12th postoperative day. The other three patients recovered successfully from the operation (i.e., they were discharged from hospital with the functional status in New York Heart Association Class I or II). We conclude that the Batista operation provides a real hope for patients with end-stage dilated cardiomyopathy.

Adult↗
PubMed1996

Recombinant Plasmodium falciparum dihydrofolate reductase-based in vitro screen for antifolate antimalarials.

We describe the system for screening the effective antifolate antimalarials that uses the recombinant Plasmodium falciparum DHFR domain of the bifunctional DHFR-TS expressed in Escherichia coli, and were designed with amino acid alterations found in the DHFR genes of the antifolate resistant strains. The validity of the screen was verified by the subsequent examination of several substituted pyrrolo[2,3-d]pyrimidines for their antimalarial activity. Among the 120 chemical derivatives, 5 compounds were identified by their preferential inhibition of the drug sensitive pfDHFR to that of the mammalian isoenzyme. As compared to the sensitive enzyme, the decrease in response of the cycolguanil-resistant and pyrimethamine-resistant enzymes to the selected compounds were relatively moderate. This gave folds decrease in sensitivity of 0.8-7.5 and 3.6-29, respectively, while those for cycloguanil and pyrimethamine were 400 and 308. The compounds inhibited the growth of drug-sensitive cultured P. falciparum with 50% effective concentrations of the ranged 0.17-30 nM. As contrasted with the sensitive strain, the fold decrease in sensitivity of the resistant parasites were 0.9-2 and 15-50 in the case of the test compounds, while those for cycloguanil and pyrimethamine were 690 and 20,500. Moreover, the most selective pyrrolo-pyrimidine (P-1) showed in vivo activity against P. berghei in mice.

Animals↗
PubMed1996

Roles of Tyr103 and Tyr264 in the regulation of RecA-DNA interactions by nucleotide cofactors.

The DNA-binding mode of the RecA protein, in particular its dependence on nucleotide cofactor, has been investigated by monitoring the fluorescence and linear-dichroism signals of a tryptophan residue inserted in the RecA to replace tyrosine at position 103 or 264. These residues are important for cofactor and DNA binding, as evidenced from their fluorescence changes upon binding of cofactor and DNA [Morimatsu, K., Horii, T. & Takahashi, M. (1995) Eur. J. Biochem. 228, 779-785]. The substitution of these residues with tryptophan does not affect the structure or biological function of the complex and can therefore be exploited to gain structural information in terms of the orientation and environment of the inserted reporter chromophore. The fluorescence change upon formation of the ternary cofactor.RecA. DNA complex was much smaller than the sum of the changes induced by cofactor or DNA alone. This difference indicates that the cofactor and DNA interact with RecA via common components. The fluorescence change caused by DNA in the presence of cofactor was almost independent of the base composition of DNA, in contrast to the interaction in the absence of cofactor. Hence, the contact mode between the selected residues and DNA in the complex may depend significantly on the cofactor. Linear-dichroism measurements indicate that the cofactor does not markedly alter the organization of RecA filament. Linear dichroism shows that neither the aromatic moiety of residue 103 nor that of residue 264 is intercalated between the DNA bases. The textural changes reported for the helical pitch and contour length of RecA fiber upon interaction with cofactor and DNA may derive from a subtle change in orientation of the RecA subunits in the filament.

Amino Acid Sequence↗
PubMed1996

Production of recombinant SERA proteins of Plasmodium falciparum in Escherichia coli by using synthetic genes.

We expressed two regions of the serine repeat antigen (SERA) protein of Plasmodium falciparum in Escherichia coli by synthesizing the genes with a changed codon usage. One of the synthetic gene sequences encodes amino acid residues 17-382 (SE47') and the other encodes amino acid residues 586-802 (SE50A). The products produced by the synthetic gene sequences in E. coli accounted for 15-30% of the total bacterial protein. Antisera against both the purified gene products prepared in rats inhibited malaria parasite growth in vitro. The anti-SE47' serum was significantly more inhibitory than the anti-SE50A serum. The described methods provide a large scale preparation of recombinant antigens for improving and producing malaria vaccine.

Amino Acid Sequence↗
PubMed1996

Gastroepiploic artery graft in 400 patients.

The right gastroepoploic artery (GEA) has been used for coronary artery bypass grafting (CABG) in 400 patients of a total of 1359 undergoing the same procedure during an 8-year period. There were 327 males and 73 females with a mean age of 59 years. Single-, double- and triple-vessel and left main disease were noted in 4, 51, 283 and 62 patients, respectively. Previous myocardial infarction was noted in 208 patients and 40 patients had undergone previous CABG. Internal thoracic artery (ITA) and inferior epigastric artery grafts were concomitantly used in 388 (97%) and 30 (8%) patients, respectively. The mean number of grafts was 3.2 including vein grafts, and 2.3 coronary arteries were bypassed with arterial grafts. The sites of GEA grafting were 43 anterior descending, 6 diagonal, 71 circumflex, and 287 right coronary arteries with 376 in situ and 24 free grafts including 7 sequential grafts. There were eight (2%) early and five (1.3%) late deaths. New Q waves were noted in six (1.5%) patients. Warm body circulation is thought to be favorable with a lower incidence of the need for intra-aortic balloon pump (0.6% vs 6.0%). Postoperative angiography revealed 94% (253/268) early (2 months) and 94% (47/50) late (2-5 years) patency of GEA grafts. In conclusion. GEA is a safe and effective arterial conduit for CABG.

Abdominal Muscles↗
PubMed1996

Protective role of CD40 in Leishmania major infection at two distinct phases of cell-mediated immunity.

CD40-deficient mice are susceptible to Leishmania major infection while their wild-type littermates can resolve the infection. Upon stimulation with L. major antigens, draining lymph node T cells of the mutant mice and the susceptible mice, BALB/c, secrete comparable amounts of IL-4. The mutant mice produce less IFN gamma than wild-type mice. The expression of IL-12 p40 mRNA was significantly lower in L. major antigen-stimulated cells of mutant mice than those of wild-type or BALB/c mice. In normal mice, engagement of CD40 activates macrophages to a leishmanicidal state in vitro in the presence of IFN gamma. The results suggest that the CD40-CD40 ligand interaction plays an important role in two critical steps of cell-mediated immunity to L. major infection: the generation of a Th1 response and activation of macrophages to a leishmanicidal state.

Animals↗
PubMed1996

Purification and characterization of XRad51.1 protein, Xenopus RAD51 homologue: recombinant XRad51.1 promotes strand exchange reaction.

BACKGROUND: The RAD51 gene of Saccharomyces cerevisiae is homologous to the Escherichia coli recA gene and plays a key role in genetic recombination and DNA double-strand break repair. To construct an improved experimental system of homologous recombination in higher eukaryotes, we have chosen the South African clawed frog, Xenopus laevis, whose egg extracts might be useful for the in vitro studies. We identified and characterized a Xenopus homologue of RAD51 gene, the XRAD51.1. RESULTS: Recombinant XRad51.1 was expressed in E. coli. The purified XRad51.1 protein showed ssDNA-dependent ATPase activity and promoted the DNA strand exchange reaction between two 55-mer oligonucleotides. The binding stoichiometry of XRad51.1 to ssDNA was determined by fluorescence of poly(d epsilonA), a chemically modified poly(dA), and was found to be about six bases/XRad51.1 monomer in a nucleoprotein filament, a similar value to E. coli RecA protein. The kinetics of the fluorescence change of poly(d epsilonA) after XRad51.1 binding in the presence of ATP was significantly different from that observed with RecA protein. The affinity of XRad51.1 to ssDNA in the presence of ATP was higher than that of RecA protein, and the dissociation of the XRad51.1-ssDNA complex was slower than the RecA-ssDNA complex. CONCLUSIONS: Purified recombinant XRad51.1 protein promoted the strand exchange between short DNA molecules. While the binding stoichiometry of XRad51.1 protein to ssDNA was identical to that of the RecA protein, XRad51.1 has a significantly higher affinity and binding stability to ssDNA than did the RecA protein in the presence of ATP.

Adenosine Triphosphate↗
PubMed1996

Long-term outcome of percutaneous transluminal coronary angioplasty and coronary bypass surgery for multivessel coronary artery disease.

We studied the short- and long-term outcomes of 97 patients treated with percutaneous transluminal coronary angioplasty (PTCA) and 72 patients treated with coronary artery bypass graft surgery (CABG) for multivessel coronary artery disease in a single hospital in 1989. Patients treated with CABG had a higher angina class, a higher incidence of diabetes mellitus and a greater extent of the disease. Complete revascularization was achieved in 61 patients (85%) with CABG and in 45 patients (46%) with PTCA (p < 0.001). Initial success of PTCA and CABG was obtained in 95% and 94% of the patients with PTCA and CABG, respectively. Actuarial survival rates at 5 years were similar (96% in the PTCA group; 94% in the CABG group). Fewer patients suffered from cardiac death or myocardial infarction in the CABG group than in the PTCA group, but this difference was not significant. The rate of survival free from death, myocardial infarction, CABG and repeat PTCA, was significantly higher in the CABG group than in the PTCA group (85% vs 48%; p < 0.001). These results suggest that CABG provides a favorable long-term outcome in patients with multivessel coronary artery disease and that PTCA provides a similar outcome in these patients when applied to suitable lesions, although more patients who undergo PTCA require repeat procedures.

Aged↗
PubMed1996

[A case of familial cardiac myxoma].

We experienced a case of familial cardiac myxoma observed in a mother and her daughter. A 58-year-old woman was addmited to our hospital because of repeated cerebral embolism. Echocardiography showed a left atrial myxoma to be considered as the cause of cerebral embolism. At the operation, 3 myxomas were found in the left atrium, and were removed successfully. No recurrence has been observed for 14 years after the operation. Three years after that, her 3rd child, 31-year-old-women, suffered from cerebral embolism and was also diagnosed as a left atrial myxoma. A friable myxoma was removed with the interatrial septum. She had no recurrence for 11 years after the operation. In patients with cardiac myxoma who have unusual biologic behavior, including familial myxoma, "complex" type myxoma must be suspected. We suggest that it is important to distinguish patients with "complex" type myxoma, because the recurrence rate is much higher in those than in patients with "sporadic" type myxoma.

Adult↗
PubMed1995

DNA-binding surface of RecA protein photochemical cross-linking of the first DNA binding site on RecA filament.

The first DNA-binding site (site I) of RecA protein on the filament has been mapped. RecA protein was covalently cross-linked with a 55-base synthetic single-stranded DNA which was a good substrate for the RecA-mediated strand exchange reaction. The cross-linking sites of protein were determined in the regions spanning RecA residues 64-68, 89-106, 178-183, 199-216 and 257-280. The cross-linking in the residues 64-68, 89-106, 199-216 and 257-280 would be due to the cross-linking of Tyr65, Tyr103, disordered loop 2, and Tyr264, respectively. These regions form a DNA-binding surface centered around the beta-sheet spanning residues 243-257. In the P6(1) crystal filament, the DNA-binding surface is near the RecA-RecA interface but are not in the filament axis. The data implicate a mechanism whereby the DNA binding surface would be led into the filament axis by a conformational change from inactive filament as the P6(1) structure to active filament as the RecA-DNA-ATP complex.

Adenosine Triphosphate↗
PubMed1995

RAD51 homologues in Xenopus laevis: two distinct genes are highly expressed in ovary and testis.

The RAD51 gene is a eukaryotic counterpart of the Escherichia coli recA gene which is involved in genetic recombination. Two distinct Xenopus laevis RAD51 cDNA clones (XRAD51.1 and XRAD51.2) were isolated from an oocyte cDNA library using the human RAD51 cDNA (HsRAD51) as a probe. Sequence analysis revealed that 98.2% of the amino-acid residues were identical between XRAD51.1 and XRAD51.2, and that both were 95% identical to HsRAD51. Both of the XRAD51 genes were expressed at a higher level in ovary and testis than in other somatic tissues, suggesting their involvement in meiotic recombination. The expression of XRAD51.1 was about eightfold in excess of that of XRAD51.2 in all of the tissues examined. Analysis of the rates of synonymous substitution in the coding sequences of the two XRAD51 suggests that these two genes diverged about 50 million years ago. The structural similarities of the XRAD51 proteins to RecA in E. coli and Rad51 in yeasts or vertebrates are discussed.

Amino Acid Sequence↗