Biomedical subjects

N Kato

Publications and source records attributed to N Kato.

At least 397 records · Page 22Linked to original sources

PubMed1997

[Detection of methicillin-resistant Staphylococcus aureus (MRSA)--relation between respiratory tract and gastro-intestinal tract].

The study was conducted to elucidate the possibility of hospital infection of methicillin-resistant Staphylococcus aureaus (MRSA) through feces. Fecal cultures of 12 inpatients positive for MRSA in the respiratory tract and 11 inpatients negative for MRSA in the respiratory tract were performed from April to October in 1993. Fecal cultures of inpatients positive for MRSA in the respiratory tract were continued until September in 1996, finally a total of 50 cases were enrolled. MRSA was isolated from feces of 7 patients (58.3%) of the 12 patients positive for MRSA in the respiratory tract, while no MRSA was isolated from feces of 11 patients negative for MRSA in the respiratory tract. Twenty-seven patients (54.0%) of 50 patients positive for MRSA in the respiratory tract yielded MRSA in the feces. Twenty-three patients (85.2%) of the 27 patients positive for MRSA in the fecal flora had received H2-blocker, while 11 patients (47.8%) of the 23 patients negative for MRSA in the fecal flora received H2-blocker; these differences were statistically significantly (p < 0.01). These findings suggest the possible role of feces in hospital infection with MRSA and the necessity for careful administration of H2-blocker to patients positive for MRSA in the respiratory tract.

Aged↗

PubMed1997

[Rapid identification of Bilophila wadsworthia].

Biophila wadsworthia is a recently recognized nonspore-forming anaerobic gram-negative rod and is reported to be associated with various infections such as gangrenous perforated appendicitis, peritonitis, osteomyelitis and bacteremia. Although the isolation of B. wadsworthia seems to be facilitated by using Bacteroides bile esculin (BBE) agar, the reliable scheme of identification of this species has been published. This study was conducted to find simple, rapid, and reliable measures for identification of B. wadsworthia. A total of 32 B. wadsworthia-suspected clinical isolates as well as B. wadsworthia WAL 7959 and Desulfomonas pigra DSM 749, which is the species that shows bacteriological characteristics similar to B. wadsworthia, were used. Through the study of various biochemical and enzymatic tests and culture on selective media, it is indicated that a nonspore-forming, gram-negative anaerobic rod that is nonmotile, forms "black-eyed" colonies on BBE agar, and demonstrates strongly positive catalase test, positive acid phosphatase test, and no-growth on Bacterides medium or to be susceptible to colistin (10 micrograms disk) can be identified as B. wadsworthia.

Bacteriological Techniques↗

PubMed1997

In vitro activities of 10 antimicrobial agents against bacterial vaginosis-associated anaerobic isolates from pregnant Japanese and Thai women.

The in vitro activities of 10 antimicrobial agents against 159 bacterial vaginosis-associated anaerobic isolates from pregnant Japanese and Thai women were determined. Clindamycin, imipenem, cefmetazole, amoxicillin, amoxicillin-clavulanate, and metronidazole were highly active against all anaerobic isolates except Prevotella bivia and Mobiluncus species, which were resistant to amoxicillin and metronidazole, respectively. Cefotiam, ceftazidime, and ofloxacin were variably effective, while cefaclor was the least effective agent.

Adult↗

PubMed1997

Nosocomial spread of cephem-resistant Escherichia coli strains carrying multiple Toho-1-like beta-lactamase genes.

Escherichia coli HKY56, which demonstrated resistance to various beta-lactams except carbapenems, was isolated from the throat swab of an inpatient in 1994. Conjugal transfer of cephem resistance from HKY56 to E. coli CSH2 was not successful. Three cefotaxime-resistant E. coli clones harboring plasmid pMRE001, pMRE002, or pMRE003, each of which carried a 3.4-, 5.8-, or 6.2-kb EcoRI fragment insert, respectively, were obtained from HKY56. Although restriction analysis suggested their different origins, these clones showed similar profiles of resistance to various beta-lactams. The sequence of 10 amino acid residues at the N terminus of beta-lactamase purified from E. coli HB101(pMRE001) was identical to that of Toho-1. This Toho-1-like beta-lactamase-1 (TLB-1) was able to hydrolyze cefoperazone and cefotaxime efficiently, but it failed to hydrolyze cephamycins. A Toho-1-specific DNA probe was hybridized with three distinct EcoRI fragments derived from the chromosomal DNA of strain HKY56, and these fragments corresponded to DNA inserts carried by pMRE001, pMRE002, and pMRE003, respectively. PCR and Southern hybridization analysis suggested that all six cephem-resistant E. coli strains, strains HKY273, HKY285, HKY288, HKY305, HKY316, and HKY335, which were isolated in 1996 at the same hospital where strain HKY56 had been isolated, also possessed multiple Toho-1-like beta-lactamase (TLB) genes, and the hybridization patterns obtained with the Toho-1-specific probe were quite similar among these six isolates. The DNA fingerprinting patterns observed by pulsed-field gel electrophoresis revealed that among the E. coli isolates tested, all isolates except HKY56 possessed a similar genetic background. These findings suggested that E. coli strains that carry chromosomally multiplied TLB genes may have been proliferating and transmitted among patients in the same hospital.

Carbapenems↗

PubMed1997

In vivo selection of Klebsiella pneumoniae strains with enhanced quinolone resistance during fluoroquinolone treatment of urinary tract infections.

We report two cases of failure of fluoroquinolone treatment of urinary tract infections with Klebsiella pneumoniae strains harboring quinolone resistance-associated alterations in GyrA and ParC and in vivo selection of posttreatment isolates with enhanced fluoroquinolone resistance. Active efflux leading to decreased accumulation of a drug enhanced fluoroquinolone resistance in one posttreatment isolate, and an additional mutation in parC resulting in an additional amino acid change in ParC was associated with increased resistance in the other.

Aged↗

PubMed1997

Purification and properties of methyl formate synthase, a mitochondrial alcohol dehydrogenase, participating in formaldehyde oxidation in methylotrophic yeasts.

Methyl formate synthase, which catalyzes methyl formate formation during the growth of methylotrophic yeasts, was purified to homogeneity from methanol-grown Candida boidinii and Pichia methanolica cells. Both purified enzymes were tetrameric, with identical subunits with molecular masses of 42 to 45 kDa, containing two atoms of zinc per subunit. The enzymes catalyze NAD(+)-linked dehydrogenation of the hydroxyl group of the hemiacetal adduct [CH2(OH)OCH3] of methanol and formaldehyde, leading to the formation of a stoichiometric amount of methyl formate. Although neither methanol nor formaldehyde alone acted as a substrate for the enzymes, they showed simple NAD(+)-linked alcohol dehydrogenase activity toward aliphatic long-chain alcohols such as octanol, showing that they belong to the class III alcohol dehydrogenase family. The methyl formate synthase activity of C. boidinii was found in the mitochondrial fraction in subcellular fractionation experiments, suggesting that methyl formate synthase is a homolog of Saccharomyces cerevisiae Adh3p. These results indicate that formaldehyde could be oxidized in a glutathione-independent manner by methyl formate synthase in methylotrophic yeasts. The significance of methyl formate synthase in both formaldehyde resistance and energy metabolism is also discussed.

Alcohol Oxidoreductases↗

PubMed1997

Regulation of the formate dehydrogenase gene, FDH1, in the methylotrophic yeast Candida boidinii and growth characteristics of an FDH1-disrupted strain on methanol, methylamine, and choline.

The structural gene (FDH1) coding for NAD(+)-dependent formate dehydrogenase (FDH) was cloned from a genomic library of Candida boidinii, and the FDH1 gene was disrupted in the C. boidinii genome (fdh1 delta) by one-step gene disruption. In a batch culture experiment, although the fdh1 delta strain was still able to grow on methanol, its growth was greatly inhibited and a toxic level of formate was detected in the medium. In a methanol-limited chemostat culture at a low dilution rate (0.03 to 0.05 h[-1]), formate was not detected in the culture medium of the fdh1 delta strain; however, the fdh1 delta strain showed only one-fourth of the growth yield of the wild-type strain. Expression of FDH1 was found to be induced by choline or methylamine (used as a nitrogen source), as well as by methanol (used as a carbon source). Induction of FDH1 was not repressed in the presence of glucose when cells were grown on methylamine, choline, or formate, and expression of FDH1 was shown to be regulated at the mRNA level. Growth on methylamine or choline as a nitrogen source in a batch culture was compared between the wild type and the fdh1 delta mutant. Although the growth of the fdh1 delta mutant was impaired and the level of formate was higher in the fdh1 delta mutant than in the wild-type strain, the growth defect caused by FDH1 gene disruption was small and less severe than that caused by growth on methanol. As judged from these results, the main physiological role of FDH with all of the FDH1-inducing growth substrates seems to be detoxification of formate, and during growth on methanol, FDH seems to contribute significantly to the energy yield.

Amino Acid Sequence↗

PubMed1997

Hepatitis C virus nonstructural region 5A protein is a potent transcriptional activator.

The hepatitis C virus (HCV) nonstructural region 5A (NS5A) protein, without its 146 amino-terminal amino acids and fused to the DNA-binding domain of GAL4, strongly activates transcription in yeast and human hepatoma cells. Transcriptional activation by the HCV NS5A protein may play a role in viral replication and hepatocarcinogenesis.

Amino Acid Sequence↗

PubMed1997

Traumatic thoracic aortic aneurysm: treatment with endovascular stent-grafts.

PURPOSE: To demonstrate the feasibility and safety of endovascular stent-graft placement for treatment of traumatic aortic aneurysm. MATERIALS AND METHODS: Ten patients with traumatic aortic aneurysm were treated with endovascular stent-grafts. Three patients had an acute traumatic aneurysm; seven had a chronic aneurysm. Stent-grafts were constructed from modified Z-stents covered with woven polyester or expanded polytetrafluoroethylene graft material and were deployed through a 20-24-F delivery sheath in an exposed artery located remotely from the lesion. RESULTS: Stent-graft placement and thrombosis of the aneurysmal sac were successful in all patients. Major complications were encountered in three patients after endovascular treatment. One patient had a peri-graft leak; complete thrombosis of the aneurysmal sac was achieved after coil embolization of the leak. Transposition of the left subclavian artery was necessary to relieve left arm ischemia in another patient. In the third patient, stent placement in the left main stem bronchus was needed to relieve left lung atelectasis. All patients were alive and without complications during the follow-up period (mean, 15 months). CONCLUSION: Transluminal placement of endovascular stent-grafts is a technically feasible method for treatment of traumatic thoracic aortic aneurysm and may be an effective alternative to open-chest surgery.

Accidents, Traffic↗

PubMed1997

Thoracic aortic aneurysm repair with endovascular stent-grafts.

The purpose of the study was to describe the clinical experience is using endoluminal stent-grafts for the treatment of thoracic aortic aneurysms in high-risk patients. Patients with aneurysms of the descending thoracic aorta who were considered high surgical risks underwent evaluation for endoluminal repair. The prosthesis was constructed from Z stents covered with polyester fabric using dimensions based upon preprocedural computed tomography scans and angiography. Through a femoral arteriotomy or left retroperitoneal flank incision, a 22-24 Fr delivery catheter was inserted and advanced through the aorta to the target site under fluoroscopic guidance in the operating suite. The stent-graft prosthesis was deployed at the site of the aneurysm. 44 patients (36 male, 8 female; mean age 36 years) underwent stent-graft repair for thoracic aneurysms (mean diameter 6.3 cm). The deployment was technically successful in all cases, with complete aneurysm thrombosis in 88%. The 30-day perioperative mortality rate was 6.8% and 35-month actuarial survival was 82%. There were no cases of stent migration, surgical conversion or intraprocedural death. Paraplegia occurred in two patients who underwent simultaneous surgical infrarenal aortic aneurysm repair immediately followed by stent-graft placement for a coexisting thoracic aneurysm. The conclusion was that placement of endoluminal stent-grafts for repair of thoracic aortic aneurysms is technically feasible in high-risk patients in whom conventional surgery is contraindicated. Long-term studies are needed to determine protection against aneurysm rupture and patient survival.

Adult↗

PubMed1997

Essential roles of the winged helix transcription factor MFH-1 in aortic arch patterning and skeletogenesis.

Mesenchyme Fork Head-1 (MFH-1) is a forkhead (also called winged helix) transcription factor defined by a common 100-amino acid DNA-binding domain. MFH-1 is expressed in non-notochordal mesoderm in the prospective trunk region and in cephalic neural-crest and cephalic mesoderm-derived mesenchymal cells in the prechordal region of early embryos. Subsequently, strong expression is localized in developing cartilaginous tissues, kidney and dorsal aortas. To investigate the developmental roles of MFH-1 during embryogenesis, mice lacking the MFH-1 locus were generated by targeted mutagenesis. MFH-1-deficient mice died embryonically and perinatally, and exhibited interrupted aortic arch and skeletal defects in the neurocranium and the vertebral column. Interruption of the aortic arch seen in the mutant mice was the same as in human congenital anomalies. These results suggest that MFH-1 has indispensable roles during the extensive remodeling of the aortic arch in neural-crest-derived cells and in skeletogenesis in cells derived from the neural crest and the mesoderm.

Animals↗

PubMed1997

Antirheumatic agents. III. Novel methotrexate derivatives bearing an indoline ring and a modified ornithine or glutamic acid.

The synthesis, biological profile and structure-activity relationship of various methotrexate (MTX) derivatives bearing an indoline ring are described. In particular, Nb-(3-carboxyphenyl)-N alpha-[1-[(2,4-diaminopteridin-6-yl)-methyl] indoline-5-ylcarbonyl]-L-glutamine (3d), compared to MTX, exhibited an enhanced anti-proliferative effect on human peripheral blood mononuclear cells obtained from healthy volunteers.

Antirheumatic Agents↗

PubMed1997

Angina pectoris after recovery from an acute coronary event--the role of psychological factors in Japanese vs North American patients.

To determine whether specific psychological characteristics are associated with angina pectoris in clinically stable patients 1 to 6 months after recovery from an acute coronary event, a battery of tests was administered to 92 Japanese and 646 North American participants (22% females) in the Multicenter Study of Myocardial Ischemia. Of these 738 patients, 541 had originally suffered acute myocardial infarction, 188 had unstable angina, and 9 were admitted for other acute ischemic events. At the time of enrollment, an average of 2.7 months after the index event, 205 patients reported having had anginal symptoms during the preceding months. Compared to those who did not report angina, these patients scored higher on a modified Autonomic Perception Questionnaire (p = 0.04) and lower on the Internal Health Locus of Control Scale (p = 0.004). These differences were generalized across the Japanese and North American cohorts. These results indicate that in these patients, angina pectoris was associated with an increased awareness of a wide range of physical symptoms and a decreased sense of personal control over one's own health and prognosis.

Acute Disease↗

PubMed1997

Ester synthesis by NAD(+)-dependent dehydrogenation of hemiacetal: production of methyl formate by cells of methylotrophic yeasts.

A water-soluble ester, methyl formate, was detected as a metabolite in the culture medium of methylotrophic yeasts. Methyl formate synthase, which catalyses NAD(+)-dependent dehydrogenation of the hemiacetal adduct of methanol and formaldehyde, catalyses the ester synthesis. The enzyme activity was induced on a methanol medium and was increased further by the addition of formaldehyde. In the reaction system using intact cells of Pichia methanolica AKU 4262, 135 mM (8.1 g/liter) methyl formate was produced from 2 M methanol. This is a new biological process for ester synthesis that couples spontaneous formation of hemiacetal and alcohol dehydrogenase.

Esters↗

PubMed1997

Strain-gauge force transducer method for evaluating urethral motility in conscious dogs.

A new method has been developed that is suitable for physiological studies of urethral motility in the conscious state with a strain-gauge force transducer (force transducer). In anesthetized dogs, the contractile or relaxing responses of the urethral smooth muscle in the direction of the circular layers measured with the force transducer, elicited by either phenylephrine or isoproterenol, were significantly correlated to the increase or decrease in the intra-urethral pressure (r = 0.998 and 0.780, respectively). In conscious dogs, the fluctuation in the urethral tone was observed to be less than in the intra-urethral pressure, and a dose-dependent response to phenylephrine (1-30 micrograms./kg. i.v.) and isoproterenol (0.1-3 micrograms./kg. i.v.) was clearly recognized. Moreover, this conscious model provided a fairly reproducible pattern with the urethral contraction or relaxation related to the filling or voiding phase of the cystometrogram, which was abolished by anesthetization. These results indicate that the present force transducer method makes it possible to evaluate the further physiological characteristics of urethral motility in conscious dogs.

Animals↗

PubMed1997

[Antiemetic efficacy of granisetron in repeated CAF chemotherapy after breast cancer operation].

The antiemetic efficacy of granisetron in repeated CAF chemotherapy after breast cancer operation was investigated. Twenty-three patients who were treated with repeated CAF chemotherapy after breast cancer operation received drip-infused granisetron (3 mg/body) to prevent nausea and vomiting. Antiemetic efficacy was evaluated by means of the severity of nausea and the frequency of vomiting. The antiemetic efficacy rate of the drug was 74.4%. However, the average rate of antiemetic efficacy was 86.9% on the first through the sixth administration of the chemotherapy (first period). 75.9% on the seventh through the twelfth (second period), 48.4% on the thirteenth through the eighteenth (third period), and 31.8% on the nineteenth through the twenty-fourth (fourth period). There were significant differences in the antiemetic efficacy rate among the first, second and third periods. The antiemetic efficacy of granisetron decreased significantly by repeated CAF chemotherapy.

Adult↗

PubMed1997

Trigonal splitting is a major complication of endoscopic trigonoplasty at 1-year followup.

PURPOSE: The long-term results of endoscopic trigonoplasty in patients with vesicoureteral reflux were investigated. MATERIALS AND METHODS: We performed endoscopic trigonoplasty in 28 patients with vesicoureteral reflux, including 6 girls 6 to 8 years old. Reflux was grade I in 14 reno-ureteral units, grade II in 15, grade III in 8, grade IV in 1 and grade V in 1. Median followup was 23 months. RESULTS: At a median of 3 months postoperatively vesicoureteral reflux was not apparent in 37 units (95%) and it was downgraded in 1 (3%). At a median of 12 months postoperatively 27 (79%) and 4 (12%) of the 34 ureters had cessation and downgrading, respectively. Of the 13 select patients who underwent cystoscopy 3 had retreating ureteral orifices and 5 had trigonal splitting 6 to 12 months postoperatively. Vesicoureteral reflux was demonstrated in 3 of the 5 patients (4 ureters) with trigonal splitting and in 1 (1 ureter) with retreating ureteral orifices. At a median of 24 months after surgery voiding cystography showed reflux in only 1 of 15 units. No postoperative upper urinary tract dilatation was noted at followup. CONCLUSIONS: Cessation rates of vesicoureteral reflux 12 months after endoscopic trigonoplasty were low with a high incidence of trigonal splitting. These unsatisfactory results mandate technical refinements to avoid trigonal splitting.

Adolescent↗

PubMed1997

[Effects of toborinone on systemic circulation in patients under general anesthesia].

Patients with suppressed systemic circulation under general anesthesia received a 20-minute continuous infusion of toborinone at a rate of 5, 10, or 15 micrograms.kg-1.min-1, and the efficacy and safety of the drug were evaluated. Toborinone increased cardiac index (CI) and stroke volume index (SVI) dose-dependently, with significant increases at 10 and 15 micrograms.kg-1.min-1. An increase in CI was observed from 10 minutes after the start of infusion, with a return to the baseline value at 20-30 minutes after the completion of infusion. Toborinone did not affect heart rate at any dose tested, but the drug tended to decrease mean pulmonary arterial pressure, pulmonary capillary wedge pressure, and right atrial pressure. Mean arterial blood pressure tended to decrease after the start of infusion at all doses tested, and was significantly decreased at 20 minutes after the start of infusion at 10 and 15 micrograms.kg-1.min-1. Systemic vascular resistance and pulmonary vascular resistance decreased at all doses tested. T-wave amplitude on electrocardiaogram (ECG) and oxygen partial pressure in arterial blood decreased at 10 and 15 micrograms.kg-1.min-1. Toborinone increases cardiac output and decreases pre-load and after-load with no effects on heart rate, and, therefore, is thought to be a positive inotropic agent useful in the treatment of circulatory insufficiency. Due care should be exercised to monitor blood pressure, ECG, and arterial blood gas parameters of the patients. The effects of toborinone need to be further investigated in patients with complicated cardiac diseases under general anesthesia and in patients with circulatory insufficiency after surgery, including patients following extracorporeal circulation.

Adult↗