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Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 289 records · Page 16Linked to original sources
PubMed1996

Structure and function of rotavirus NSP1.

Studies on the structure and function of the nonstructural proteins (NSP1-NSP5) of rotaviruses are important for dissection of the morphogenesis and replication processes of rotavirus. Above all, NSP1, the product of gene 5, has several interesting features, such as extreme sequence diversity, a highly conserved cysteine-rich region, RNA-binding activity, accumulation on the cytoskeleton, and non-random segregation in reassortment. Recently, comparable NSP1 sequence analysis has been performed on a number of rotavirus strains from various species. Furthermore, characterization of mutants with rearranged NSP1 genes has helped to elucidate the structure-function interaction of NSP1. We isolated and characterized two interesting mutants which have a large deletion including the cysteine-rich region or a nonsense codon at the early portion in the open reading frame (ORF) of the NSP1 gene. In this report, we summarize the structure and function of NSP1.

Amino Acid Sequence↗
PubMed1996

Species-specific and interspecies relatedness of NSP1 sequences in human, porcine, bovine, feline, and equine rotavirus strains.

We have sequenced gene 5 encoding NSP1 for three human, two porcine, two bovine, one feline, and five equine rotavirus strains, and compared the nucleotide and deduced amino acid sequences with the published sequences for other various strains. Subgroup I human strains L26, 69M, and DS-1 were found to have a similar NSP1 sequence despite their different G serotypes, VP4 genotypes, and RNA patterns. The NSP1 sequence of the human strain K8 showed a high degree of homology to those of porcine strains OSU and YM. A high degree of homology was found among three equine strains (H2, FI-14, and FI23), but they differed from the other equine strains L338 and H1. The strain H1 was similar to the porcine strains. The feline strain Cat2 showed a high homology to bovine strains UK, RF, and A44. Thus, species-specific and interspecies relatedness of NSP1 sequences among human, porcine, bovine, feline and equine rotaviruses was found. Overall genomic relatedness of strains L26 and YM to various human and animal strains was also examined by RNA-RNA hybridization assay. The present and previous hybridization results showed that there is a good correlation in most strains between overall genomic property (or genogroup) and NSP1 sequence homology.

Amino Acid Sequence↗
PubMed1996

G (VP7) serotype-dependent preferential VP7 gene selection detected in the genetic background of simian rotavirus SA11.

We previously found the preferential selection of VP7 gene from a parent rotavirus strain SA11 with G serotype 3 (G3) in the sequential passages after mixed infection of simian rotavirus SA11 and SA11-human rotavirus single-VP7 gene-substitution reassortants with G1, G2, or G4 specificity. However, it has not been known whether or not VP7 genes derived from other strains with G3 specificity (G3-VP7 gene) are preferentially selected in the genetic background of SA11. To address this question, mixed infections followed by multiple passages were performed with a reassortant SA11-L2/KU-R1 (SKR1) (which possesses VP7 gene derived from G1 human rotavirus KU and other 10 genes of SA11 origin) and one of the five G3-rotaviruses, RRV, K9, YO, AK35, and S3. After the 10th passage, selection rates of SA11-L2/KU-R1 gene 9 (G1-VP7 gene) and gene 5 (NSP1 gene) reduced considerably (0 to 20.4%) in the clones obtained from all the coinfection experiments, while all or some of other segments were preferentially selected from SKR1 depending on the pairs of coinfection. When viral growth kinetics was examined, SKR1 exhibited better growth and reached a higher titer than any G3 viruses. Although the generated reassortants with VP7 gene and NSP1 gene derived from G3 viruses showed almost similar growth kinetics to that of SKR1 during the first 20 h of replication, the titers of these reassortants were higher than that of SKR1 after 36 h postinfection. The results obtained in this study suggested that G3-VP7 gene is functionally more adapted to the genetic background of SA11.

Animals↗
PubMed1996

Continuous monitoring of ventilatory mechanics during one-lung ventilation.

OBJECTIVE: The Ultima SV respiratory monitor can be used to monitor the intraoperative effects of the lateral decubitus position and one-lung ventilation on ventilatory mechanics. METHODS: Eight patients with esophageal cancer who required one-lung ventilation for esophagectomy and reconstruction were enrolled in the study. We monitored pressure-volume or flow-rate-volume loops continuously throughout the operation. Respiratory parameters were evaluated closely during five conditions of ventilation: two-lung ventilation in the supine position, two-lung ventilation in the lateral decubitus position, dependent one-lung ventilation in the lateral decubitus position, nondependent one-lung ventilation in the lateral decubitus position, and dependent one-lung ventilation in the lateral decubitus position with the chest opened. Respiratory rate was controlled at 10 breaths/min, and tidal volume was kept constant (10 ml/kg) during surgery. RESULTS: Peak inspiratory pressure increased to 29.0 +/- 9.0 (mean +/- SD) cm H2O in the dependent one-lung in the lateral decubitus position with the chest opened (p < 0.01). Dynamic compliance decreased to 29.4 +/- 4.9 ml/cm H2O in the dependent one-lung in the lateral decubitus position with the chest opened (p < 0.01). The changing configuration of the loops also offered additional and instantaneous information during one-lung ventilation. CONCLUSIONS: One-lung ventilation caused several changes in the whole respiratory system (lung, thorax, and endotracheal tube). Continuous monitoring of flow-rate-volume or pressure-volume loops with in-line spirometry provided comprehensive information regarding parameters in one-lung ventilation.

Aged↗
PubMed1996

Modified antigen-binding of human antibodies with glycosylation variations of the light chains produced in sugar-limited human hybridoma cultures.

We have characterized the effects of serum and N-acetylglucosamine in a glucose-deprived condition on the glycosylation of antibody light chains, as well as the resulting biological properties of those antibodies. We have chosen for our investigation the human hybridoma lines producing monoclonal antibodies reactive to lung adenocarcinoma. Each antibody possess a N-glycosylated carbohydrate chain in the hypervariable region of the light chains. When the cell lines were grown in the absence of glucose, variant light chains with varying molecular masses were found to be secreted. Analysis of these light chains produced in a glucose-deprived condition revealed that the changed molecular-mass of the variant light chains is due to different glycosylation. Addition of N-acetylglucosamine or fetal calf serum to the glucose-free medium led to the creation of other light chains that exhibit increased antigen binding activity.

Acetylglucosamine↗
PubMed1996

Respiratory mechanics and arterial blood gases during and after laparoscopic cholecystectomy.

PURPOSE: The purpose of this study was to assess the effects of increased intra-abdominal pressure due to CO2 insufflation on the mechanical characteristics of the respiratory system and arterial blood gases during and after laparoscopic cholecystectomy. METHODS: Respiratory mechanics and arterial blood gases were examined in 12 patients undergoing laparoscopic cholecystectomy with CO2 insufflation. Respiratory mechanics were continuously monitored with in-line spirometry. In the recovery room, PaCO2 was measured in this group at 30 min and compared with PaCO2s in 23 patients who had undergone open cholecystectomy retrospectively, to evaluate the effects of insufflation on CO2 elimination. RESULTS: Minute ventilation was decreased by about 500 ml.min-1 during abdominal insufflation. Dynamic lung compliance decreased from 49.6 +/- 4.7 to 30.7 +/- 2.3 (mean +/- SEM) ml.cmH2O-1 with abdominal insufflation (P < 0.005), and returned to 45.1 +/- 3.1 after the release of pneumoperitoneum. Peak inspiratory pressure increased from 15.9 +/- 0.9 to 18.9 +/- 1.0 cmH2O with abdominal insufflation (P < 0.05). Arterial blood gas determinations indicated a decrease in arterial pH, with CO2 retention during insufflation and in the recovery room (P < 0.05). PaCO2 of the laparoscopic patients was higher than that of the open patients in the recovery room. CONCLUSION: The results indicate that respiratory acidosis was caused during CO2 insufflation for laparoscopic cholecystectomy, that was due to (1) decreased compliance, (2) increased CO2 load and (3) insufficient ventilation. Accumulated CO2 during laparoscopic cholecystectomy increased PaCO2 level in the recovery room.

Adult↗
PubMed1996

Glucose intolerance during prolonged sevoflurane anaesthesia.

PURPOSE: The effects of prolonged sevoflurane anaesthesia on insulin sensitivity were investigated by two successive intravenous glucose tolerance tests (IVGTT) in eight patients who underwent prolonged surgery. METHODS: The first IVGTT was administered (25 g glucose as 20% dextrose in water iv) over two minutes 35 min after initiation of surgery. Arterial blood samples were obtained at 0, 5, 10, 30, 60, and 120 min after glucose administration for blood glucose and plasma insulin determination. A second IVGTT was performed six hours following the initiation of surgery. RESULTS: The disappearance rate of glucose (k-value) for the first IVGTT was 0.887 +/- 0.436 (mean +/- SD) %.min-1, and 0.784 +/- 0.289 for the second IVGTT. Both k-values are lower than the normal value. The maximum insulin response to glucose (delta IRI-delta BS-1) of the second IVGTT was lower than the first IVGTT (0.124 +/- 0.092 vs 0.071 +/- 0.056, P < 0.05). The total insulin output of the first IVGTT was higher than the second IVGTT (1.161 +/- 830 vs 568 +/- 389 microU.min.ml-1, P < 0.05). CONCLUSION: Glucose intolerance is enhanced by diminished insulin output in response to blood glucose elevation during prolonged anaesthesia and surgery.

Aged↗
PubMed1996

Repair of postinfarction ventricular septal defect on a beating heart.

Two elderly patients with postinfarction ventricular septal defect underwent repair by endocardial patch with infarct exclusion on a beating heart under normothermic cardiopulmonary bypass with ultra-short-acting beta-blocker infusion. Their hemodynamic states soon recovered, and postoperative angiographic studies showed improvement of cardiac function and no residual shunt. Ultra-short-acting beta-blocker has the potential to facilitate safe repair of postinfarction ventricular septal defect on a beating heart, and this operative approach can be beneficial for myocardial protection.

Adrenergic beta-Antagonists↗
PubMed1996

Selection of rotavirus VP7 gene in the genetic background of simian rotavirus SA11: implications for rotavirus reassortant vaccine development.

We previously reported that the VP7 gene from simian rotavirus SA11 with G-serotype 3(G3-VP7 gene) was preferentially selected in the genetic background of SA11 compared with the G1- or G2-VP7 gene. In the present study, selection of the G4-VP7 gene in competition with G1-, G2- or G3-VP7 gene in the SA11 background was analyzed through mixed infection experiments using SA11 and SA11-human rotavirus single-VP7 gene-substitution reassortants with G-serotypes 1, 2, and 4 (G1-, G2- and G4-reassortant). In virus clones from coinfection of SA11 and G4-reassortant, the frequency of G4 virus decreased to 7% at the 3rd passage and the G4 virus disappeared at the 10th passage, whereas the majority of the clones possessed G3 specificity. However, the predominance of either of the viruses coinfected was not observed in the mixed infection with G4-reassortant and G1- or G2-reassortant. Although growth kinetics of SA11 and G4-reassortant was similar, G4-reassortant showed significantly smaller plaque size than SA11, G1- and G2-reassortant did. These results indicated that the G3-VP7 gene from SA11 might be preferentially selected in the SA11 genetic background compared with the G4-VP7 gene, and suggested that the introduction of a single G4-VP7 gene may affect growth characteristics of recipient virus SA11. These results together with our previous findings suggested the significance of genetic compatibility between recipient viral genes and foreign VP7 gene in the development of multivalent reassortant rotavirus vaccines.

Animals↗
PubMed1996

Effect of MDP-Lys(L18) as a mucosal immunoadjuvant on protection of mucosal infections by Sendai virus and rotavirus.

To examine the effect of MDP-Lys(L18), a derivative of muramyl dipeptide (MDP), as a mucosal immunoadjuvant, we investigated its activity to augment host resistance against mucosal infections by Sendai virus and rotavirus in mice. In an experimental infection model using suckling mice (10-day-old) inoculated perorally (p.o.) with 1.5 x 10(6) p.f.u. mouse-1 of rotavirus strain SA11, intrarectal (i.r.) as well as p.o. administration of MDP-Lys(L18) (50 micrograms mouse-1) prior to virus infection markedly reduced rotavirus-induced diarrhea. Furthermore, when MDP-Lys(L18) was administered p.o. (1 mg mouse-1), i.r. (300 micrograms mouse-1) or intranasally (i.n., 100 micrograms mouse-1) various days before Sendai virus infection (2.6 x 10(4) HAD mouse-1), all the mucosal administration of MDP-Lys(L18) significantly protected a lethal infection of Sendai virus, showing a dose-dependent manner. However, the efficacy of MDP-Lys(L18) to induce the prophylactic activity against the viruses somewhat varied according to the administration route and timing. In time course analysis of virus isolation in vivo, the mice administered with MDP-Lys(L18) exhibited a significant reduction of both viruses in the lungs for Sendai virus and in the bowels for rotavirus. These results suggest that MDP-Lys(L18) is a potent mucosal immunoadjuvant to enhance nonspecific host resistance against two mucosal infectious viruses, Sendai virus and rotavirus.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1996

The distribution of G and P types within isolates of bovine rotavirus in Japan.

Various combinations of G type and P type were observed in 76 bovine rotavirus (BRV) strains isolated from 235 diarrheal calves in three prefectures of Japan in 1992-1994. The most prevalent combination was G6:P5 (46/76, 60.5%), followed by G10:P11 (13/76, 17.1%), G6:P11 (7/76, 9.2%) and G10:P5 (5/76, 6.6%). No G6:P1 strain of BRV was recognized from the isolates in the present study, though this type of BRV is well known as a suitable vaccine strain against BRV infection.

Animals↗
PubMed1996

Attenuation of cardiopulmonary bypass-derived inflammatory reactions reduces myocardial reperfusion injury in cardiac operations.

In cardiac operations endopeptidase (protease) inhibitor may be beneficial in reducing myocardial injury when administered in the cardiopulmonary bypass prime. Nafamostat mesilate was evaluated in 20 patients who underwent coronary artery bypass grafting. The patients were divided into a control group (n = 10) and a nafamostat group (n = 10). Nafamostat (2 mg/kg per hour) was continuously given during cardiopulmonary bypass in the nafamostat group. The age, number of grafts, cardiopulmonary bypass time, and aortic crossclamp time were similar between groups. In the control group, neither tumor necrosis factor-alpha nor interleukin-1 levels showed any significant change during cardiopulmonary bypass, whereas interleukin-6 and interleukin-8 levels, percent expression of adhesion molecule (CD18) on neutrophils, and CH50 assay results increased significantly during cardiopulmonary bypass. As compared with the control group, the nafamostat group showed significantly lower levels of interleukin-6 (123 +/- 57 versus 40 +/- 22 pg/ml, respectively) and interleukin-8 (96 +/- 13 versus 66 +/- 14 pg/ml, respectively). The nafamostat group showed a significantly lower difference of CH50 assay results and malondialdehyde levels between coronary sinus blood and arterial blood and peak values of creatine kinase MB (43 +/- 12 IU/L versus 19 +/- 6 IU/L) during the postoperative course compared with findings in the control group. These results demonstrated that inflammatory reactions induced by cardiopulmonary bypass had adverse effects on myocardial recovery after aortic crossclamping and that nafamostat mesilate given during cardiopulmonary bypass appeared to reduce myocardial reperfusion injury by attenuating such inflammatory reactions. Attenuation of inflammatory reactions of cardiopulmonary bypass should be considered in the strategy of myocardial protection.

Benzamidines↗
PubMed1996

Genomic diversity of mec regulator genes in methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

Low-affinity penicillin-binding protein PBP-2a encoded by mecA is closely related to methicillin resistance in staphylococci, and expression of PBP-2a is controlled by regulator elements encoded by mecR1 and mecI which are located adjacent to mecA on the chromosome. Deletion or mutation which occurred in mec regulator gene is considered to be associated with constitutive production of PBP-2a. The distribution of the mec regulator genes in 176 strains of Staphylococcus aureus and 33 strains of S. epidermidis isolated from a single hospital was studied by polymerase chain reaction amplification. Most clinical isolates of methicillin-resistant S. aureus (MRSA) (94.3%) and S. epidermidis (MRSE) (83.9%) possessed both mecI and mecR1 genes (type I), whereas no mec regulator genes were detected in mecA-negative isolates. In contrast, 7 MRSA and 5 MRSE isolates were found to have incomplete regulator genes, and they were classified into three groups; strains which lacked only mecI gene (type II), strains which lacked mecI and 3'-end of mecR1 gene (type III), and strains which lacked both regulator genes (type IV). Analysis of mecI gene from all the strains having mecI by restriction fragment length polymorphism after Mse I digestion indicated that three MRSA strains possessed one of the known point mutations identified previously. These findings indicated the predominance of a single type of MRSA possessing both mecI and mecR1 in the study period and also suggested a high genomic diversity in mec regulator region of staphylococci.

Cross Infection↗
PubMed1996

Effects of neocarzinostatin-chimeric Fab conjugates on the growth of human pancreatic carcinoma xenografts.

Neocarzinostatin (NCS) was bound covalently to human/mouse chimeric Fab fragments of MAb A7 (chA7Fab) directed against human pancreatic carcinoma. The anti-tumour effect of chA7Fab-NCS was tested in a nude mouse model on pancreatic carcinoma and compared with A7-NCS or NCS alone. The anti-tumour effect of chA7Fab-NCS increased in a dose-dependent manner and was significantly greater than either A7-NCS or NCS. Tumour growth was completely suppressed after the administration of chA7Fab-NCS. An enzyme-linked immunosorbent assay with rabbit anti-mouse immunoglobulin was performed to examine the antigenicity of chA7Fab. ChA7Fab had less reactivity with rabbit anti-mouse immunoglobulin than either whole antibody A7 or murine Fab fragments of A7. Thus, chA7Fab-NCS can inhibit human pancreatic cancer growth in an animal and may be useful for targeting chemotherapy to pancreatic cancer in humans.

Animals↗
PubMed1996

Enhanced expression of the protein kinase substrate annexin in human hepatocellular carcinoma.

Annexin (AX) constitutes a new family of Ca2+-dependent membrane-binding proteins; 13 of them have been described. Among these, annexin-1 (AX-I) has displayed many biological functions in vitro. Its actual role in vivo, however, remains unknown. We already reported that AX-I was expressed in proliferating (regenerating) hepatocytes at both protein and messenger RNA (mRNA) levels. The role of AX-I in human hepatocellular carcinoma (HCC) remains obscure. In this study, the amounts of AX-I at protein and mRNA levels, as well as its localization, have been determined in the normal human liver, chronic hepatitis liver, and nontumorous and tumorous portions of HCC. AX-I was rarely found in normal and chronic liver tissues, whereas it is overexpressed at both the transcriptional and translational levels in tumorous and nontumorous regions of HCC. In addition, more AX-I was expressed in the tumorous portion than the nontumorous portion of HCC. AX-I was present in the hepatocytes and HCC cells, localized mainly in the cytoplasm. AX-I was expressed in poorly differentiated cancer cells. Furthermore, AX-I was tyrosine-phosphorylated in HCC. We also found that some of the AX-I- positive hepatocytes in the nontumorous tissues were derived from a particular subset of parenchymal cells (stem or oval cells). These results indicate that AX-I plays an important role in the malignant transformation process leading to HCC and that it is closely related to the histological grade of HCC. HCC would offer a novel tool with which to study the function of AX-I in malignant transformation.

Annexin A1↗