Biomedical subjects

K Ouchi

Publications and source records attributed to K Ouchi.

At least 19 recordsLinked to original sources

PubMed1995

Isolation of a cold-sensitive fermentation mutant of a baker's yeast strain and its use in a refrigerated dough process.

Conventional baker's yeast converts sugars in dough into CO2 and ethanol to a significant extent when the dough is stored for days at 5 degrees C. We have isolated Csf (cold-sensitive fermentation) mutants of a commercial baker's yeast by a selection method including as the critical step a nystatin treatment to mutagenized cells at 10 degrees C in the presence of antimycin A. The fermentative activity of mutant strain CSF3 was substantially zero at 5 degrees C and one-fifth that of the parent at 10 degrees C but was restored to the same level as the parental activity at 25 to 40 degrees C. In contrast with the parent, the mutant strain normally produced white bread dough and butter roll dough even after the dough was stored for a week at 5 degrees C.

Antimycin A↗

PubMed1995

Analysis of strains of Burkholderia (Pseudomonas) cepacia isolated in a nosocomial outbreak by biochemical and genomic typing.

We analyzed strains of Burkholderia (formerly Pseudomonas) cepacia isolated in a nosocomial outbreak by biochemical and genomic typing methods. One hundred isolates of B. cepacia were obtained from patients at several wards in a single hospital from March 1983 to February 1984. These isolates were classified into 12 groups by a new biochemical typing scheme on the basis of the production of six enzymes and the production of hemolytic substance and yellow pigment. Among them, 33 strains collected from the 12 groups were further characterized by DNA fingerprinting by pulse-field gel electrophoresis, ribotyping, and plasmid profile analysis. Forty-seven strains of B. cepacia of independent origins and 25 isolates from the same hospital obtained 10 years later for a follow-up study were also subjected to analysis. Both DNA fingerprinting and ribotyping clearly discriminated the isolates from different hospitals. Of interest, although the biochemical typing and plasmid profiles of the isolates obtained during 1983 to 1984 in a single hospital were variable, genomic typing identified the majority of the isolates (32 of 33 [97%]) as derivatives of a single strain. Furthermore, a follow-up study suggested the persistence of such derivatives among the isolates after a decade. These results clearly indicated that the outbreak of B. cepacia infection in the hospital was nosocomial in origin. Thus, the usefulness of genomic typing for epidemiological studies of B. cepacia infection was further demonstrated. The biochemical typing revealed the marked variability of phenotypes of B. cepacia.

Bacterial Typing Techniques↗

PubMed1995

Existence of gamma-aminobutyric acid and its biosynthetic and metabolic enzymes in rat salivary glands.

To obtain more insight into the physiological role of gamma-aminobutyric acid (GABA) in rat salivary glands, we measured the concentration of GABA and the activities of its biosynthetic and metabolic enzymes, glutamate decarboxylase (GAD) and GABA transaminase (GABA-T). The GABA concentrations in rat parotid and submandibular glands were 10.0 and 14.3 nmol/g weight, respectively, which were 0.6-0.8% of the levels in the brain (cerebellum and medulla oblongata), whereas glutamic acid (Glu) was abundant in the two glands. These GABA levels in the two glands were significantly decreased by administration of semicarbazide (200 mg/kg, i.p.), a GAD inhibitor, and increased by gabaculine (50 mg/kg, i.p.), a GABA-T inhibitor. The activities of both GAD and GABA-T were also detected in homogenates of the two salivary glands, but they were lower than those in the brain. However, kinetic analysis showed that the values of Michaelis constants for Glu and GABA in both enzyme reactions in these two glands were similar to those in the brain. These results indicate that GABA and its biosynthetic and metabolic enzymes are present in rat salivary glands as well as the brain.

4-Aminobutyrate Transaminase↗

PubMed1994

Survival after surgery for cancer of the gallbladder.

The records of 45 patients with carcinoma of the gallbladder who had undergone surgical resection at least 5 years previously were reviewed retrospectively to determine which factors influence long-term survival. Seventeen patients survived at least 5 years and 23 died from recurrence (five patients were excluded from analysis). Of the 17 long-term survivors 15 had tumours superficial to the subserosa that showed a non-infiltrative growth pattern. Those alive at 5 years were more likely than short-term survivors to have tumours that were papillary (P < 0.05) or well differentiated (P < 0.01) adenocarcinoma. Venous, lymphatic and perineural invasion was more common in short- than in long-term survivors (87 versus 29 per cent, P < 0.001). Patients with tumours limited to the muscularis and those with non-infiltrative subserosal involvement are likely to have better survival and may have a chance of cure after extended cholecystectomy.

Adenocarcinoma↗

PubMed1994

Prevalence of Chlamydia pneumoniae in acute lower respiratory infection in the pediatric population in Japan.

Chlamydia pneumoniae has been established as an important etiologic agent of acute respiratory tract infection in humans, especially in adults. However, there is little information available on C. pneumoniae infection in the pediatric age group. The microimmunofluorescence test and Chlamydia pneumoniae-specific polymerase chain reaction (PCR) method were applied to reveal the role of C. pneumoniae as an etiologic agent of acute lower respiratory tract infection in children in Japan. Among 136 patients aged between 2 months and 15 years with acute lower respiratory tract infection, five patients with pneumonia were found to have recent C. pneumoniae infection by the microimmunofluorescence test. C. pneumoniae-specific PCR products were detected from specimens of four patients among these five. Neither C. trachomatis nor C. psittaci infection was found in this population. These results suggest that C. pneumoniae is an important causative agent of acute childhood pneumonia and may be the most prevalent pathogen among the genus Chlamydia that causes acute lower respiratory disease in this age group in Japan.

Acute Disease↗

PubMed1994

Construction from a single parent of baker's yeast strains with high freeze tolerance and fermentative activity in both lean and sweet doughs.

From a freeze-tolerant baker's yeast (Saccharomyces cerevisiae), 2,333 spore clones were obtained. To improve the leavening ability in lean dough of the parent strain, we selected 555 of the high-maltose-fermentative spore clones by using a method in which a soft agar solution containing maltose and bromocresol purple was overlaid on yeast colonies. By measuring the gassing power in the dough, we selected 66 spore clones with a good leavening ability in lean dough and a total of 694 hybrids were constructed by crossing them. Among these hybrids, we obtained 50 novel freeze-tolerant strains with good leavening ability in all lean, regular, and sweet doughs comparable to that of commercial baker's yeast. Hybrids with improved leavening ability or freeze tolerance compared with the parent yeast and commercial baker's yeasts were also obtained. These results suggest that hybridization between spore clones derived from a single parent strain is effective for improving the properties of baker's yeasts.

Fermentation↗

PubMed1994

Perineural tumor invasion and its relation with the lymphogenous spread in human and experimental carcinoma of bile duct. A computer-aided 3-D reconstruction study.

The pathogenesis of perineural tumor invasion was studied by computer aided 3-D reconstruction of bile duct wall from two patients submitted to surgery for hepatohilar carcinoma, in order to analyze how and via what route carcinoma reaches the perineural spaces. Rabbits with VX2 carcinoma implanted in the wall of the common bile duct were also examined. It was found that carcinomas growing along the perineural spaces had abundant connections with the tumors growing outside the nerve, especially those lurking in the lymphatics. In an additional analysis on the wall tissues of bile duct from 35 patients operated for carcinoma, the degree of invasion into perineural spaces proved to correlate with that into lymphatics much higher than with venular invasion. Thus it is likely that tumors reach distant nerves mainly via lymphatics, i.e., forming satellite lymphogenous foci around nerves and then, as a second step, breaking into the perineural spaces.

Adenocarcinoma↗

PubMed1994

Bismuth-free triple therapy for eradicating Helicobacter pylori and reducing the gastric ulcer recurrence rate.

OBJECTIVES: The goals of this study were to assess the effectiveness of a new triple therapy consisting of amoxicillin and metronidazole with plaunotol in the eradication of Helicobacter pylori infection in humans, and to determine whether this treatment regimen reduces the rate of recurrence of gastric ulcer in patients infected with H. pylori, without instituting maintenance therapy with H2-receptor antagonists. METHODS: Thirty patients with active gastric ulcer who were infected with H. pylori were first treated with omeprazole until scarring occurred. Patients then received plaunotol for 4 wk, with amoxicillin and metronidazole for 7 days. RESULTS: This triple therapy resulted in the safe eradication of H. pylori in 26 (86.7%) of 30 patients, with no recurrence of ulcer seen during a 12-month follow-up period in patients who tested negative for the presence of H. pylori. In addition, histological inflammatory changes improved in these patients. Of the four patients with persistent H. pylori infection, in three (75%), ulcers recurred. CONCLUSION: This new triple therapy was very effective in eradicating H. pylori in infected patients and in reducing the rate of recurrence of gastric ulcer in these patients.

Amoxicillin↗

PubMed1994

The radiologic presentation of Osler-Weber-Rendu disease of the liver.

A case of Osler-Weber-Rendu disease with extensive hepatic arteriovenous fistulation is described in detail. Hemodynamic and imaging data indicated hepatic artery to hepatic vein shunting. Enhanced magnetic resonance imaging demonstrated the existence of arteriovenous fistulas by virtue of simultaneous enhancement of hepatic arteries and veins. Embolization treatment was not indicated because the patient was asymptomatic despite cardiac high output.

Arteriovenous Fistula↗

PubMed1993

Obstructive jaundice associated with extrahepatic portal vein obstruction: report of two cases.

We herein report two cases of obstructive jaundice with markedly dilated collateral veins either in or around the bile duct in the setting of extrahepatic portal vein obstruction (EHPO). In the first case, a proximal splenorenal shunt provided relief of biliary stenosis as well as eradication of esophageal varices due to a decompression of portal hypertension. This evidence proved that the markedly extended collateral veins in the hepatoduodenal ligament caused biliary stenosis by compressing the bile duct. In the second case, obstructive jaundice was probably caused by cholangitis and was relieved with biliary drainage. Portal decompressive surgery was not indicated because of the slight degree of esophageal varices. The relationship between cholangitis and EHPO in these patients calls for further investigation. In cases with EHPO manifesting obstructive jaundice associated with risky esophageal varices, portal decompressive surgery is recommended as the procedure of choice.

Adolescent↗

PubMed1993

Genetic transformation of industrial yeasts using an amino acid analog resistance gene as a directly selectable marker.

Prototrophic and often polyploid yeasts of industrial use require some dominant genes as directly selective markers for the transformation. We examined the applicability of a dominant gene, ARO4-OFP, which causes the resistance to PFP plus tyrosine, to direct selection of the transformants from 2 laboratory and 6 industrial strains, including bakers', distillers', winery, and saké yeasts. Although the transformation rates were low and seemed different among strains, the ARO4-OFP gene was applicable to all strains tested for direct selection of the transformants.

Biotechnology↗

PubMed1993

Recurrence of hepatocellular carcinoma in the liver remnant after hepatic resection.

We analyzed the results of 19 patients who had intrahepatic recurrence of hepatocellular carcinoma (HCC) among 47 patients who were discharged from the hospital after having a hepatic resection in order to evaluate the factors affecting recurrence and survival. Recurrence-free survival rates were 80%, 44%, and 28% at 1, 3, and 5 years, respectively. Of the 19 patients with recurrence, 14 had multiple lesions, and 16 of the recurrences were detected within 3 years of surgery. None of the following factors correlated with recurrence: hepatic function; tumor size; presence of tumor capsule; capsular invasion; vascular invasion and intrahepatic metastasis; extent of hepatic resection; and resection with tumor-free margins. Patients having multiple recurrent HCCs, however, had larger-sized tumors at the time of resection than those with a solitary recurrence. The survival rates after recurrence were significantly better in patients with a solitary recurrence, and these patients were treated with transcatheter arterial embolization (TAE) therapy. Early detection as well as TAE for recurrent HCCs is necessary to improve long-term survival.

Carcinoma, Hepatocellular↗

PubMed1993

Nosocomial outbreak of Pseudomonas cepacia respiratory infection in immunocompromised patients associated with contaminated nebulizer devices.

From May 1990 to August 1991, 36 patients admitted to the Department of Internal Medicine in a medical school hospital with hematological malignancies or solid tumors, developed respiratory tract colonization with Pseudomonas cepacia. Sixteen (44.4%) of these patients developed pneumonia, and four (11.1%) died of respiratory failure due to P. cepacia pneumonia. Extensive survey of the hospital environment as well as equipment showed that nebulizer devices used by the patients for inhalation were contaminated with P. cepacia. Phenotypic characteristics, (production of hemolysin and extracellular enzymes [lipase, lecithinase and protease]), the Analytical Profile Index 20 NE pattern, and the pattern of DNA fingerprinting by pulse-field gel electrophoresis in clinically isolated strains and strains derived from nebulizer devices were compared. The strains of P. cepacia obtained from patients in the Department of Internal Medicine were indistinguishable from each other and also from those isolated from nebulizer devices, but were different from those isolated from patients in other departments at the same time. These results demonstrated that the outbreak of P. cepacia respiratory colonization in immunocompromised patients was a nosocomial acquisition, and probably occurred by transmission through contaminated nebulizer devices.

Adolescent↗

PubMed1993

Clinical studies of oral quinolone once daily in the treatment of lower respiratory tract infections.

The efficacy and safety of oral ofloxacin, 400 mg once daily, for the treatment of patients with lower respiratory tract infections were studied. The most common species recovered from the sputum specimens of these patients were Haemophilus influenzae, followed by Streptococcus pneumoniae (S. pneumoniae), Staphylococcus aureus (S. aureus), Gram positive cocci unidentified, Pseudomonas aeruginosa (P. aeruginosa), Morexella catarrhalis, Streptococcus epidermidis, and another Haemophilus species in this order. All these bacteria were susceptible to ofloxacin except for one strain of methicillin resistant S. aureus. A satisfactory clinical outcome was achieved in 34 of 40 patients (85%). It is concluded that ofloxacin, 400 mg once daily, is useful for patients with respiratory tract infections.

Administration, Oral↗

PubMed1993

[Restriction endonuclease (NotI) analysis of chromosomal DNA of Helicobacter pylori by PFGE].

With the goal of differentiating H. pylori in order to clarify its pathogenicity, we have conducted a restriction endonuclease of the chromosomal DNA of 24 strains of H. pylori employing the restriction endonucleases, NotI, CPOI, KpnI, and SmaI using pulsed-field gel electrophoresis (PFGE). With NotI, these 16 strains out of 24 strains were completely digested, and 16 clearly different electrophoretic patterns of NotI digested chromosomal DNA fragments were seen, permitting us to successfully differentiate H. Pylori. We also estimated the genome size of each strain, ranging from 1326 to 2360 kilobases. Using this method, we confirmed our previously established nude mouse model of infection with H. pylori by demonstrating that the mice were infected with the H. pylori administered in this study. Thus, we have demonstrated the digested with NotI by PFGE is an effective method for differentiating H. pylori and estimating the size of DNA of H. pylori.

Adult↗

PubMed1992

Portal venous pressure following splenectomy in patients with portal hypertension of differing etiology.

To clarify the effect of splenomegaly on portal hemodynamics in patients with portal hypertension and esophageal varices, manometric studies were carried out before and after splenectomy during an operation for esophageal varices. The 118 patients evaluated retrospectively had underlying liver cirrhosis (LC) (62), idiopathic portal hypertension (IPH) (42), and extrahepatic portal occlusion (EHO) (14). The weight of the spleen did not differ significantly among the three diagnostic groups: 640 +/- 473.5 g for LC, 780 +/- 414.6 g for IPH, and 683 +/- 457.2 g for EHO. Before splenectomy, portal pressure was significantly elevated in the patients with EHO (410 +/- 85.2 mm H2O) as compared to either the LC or IPH groups (348 +/- 64.1 and 348 +/- 73.5 mm H2O). Following splenectomy the reduction of portal pressure was significantly greater in the EHO group (29 +/- 15.5%) than in either the LC (18 +/- 17.4%) or IPH (19 +/- 17.0%) groups. Each group was subdivided according to severity of splenomegaly: marked (spleen weight > or = 500 g) or slight (spleen weight < 500 g). Patients with LC and marked splenomegaly showed a reduction in liver function parameters as shown by the prolongation of indocyanine retention rate at 15 min as compared to those with slight splenomegaly. Though it is not statistically significant, the average portal pressure tended to be higher among those with marked splenomegaly.(ABSTRACT TRUNCATED AT 250 WORDS)

Esophageal and Gastric Varices↗

PubMed1991

Isolation and genetic study of p-fluoro-DL-phenylalanine-resistant mutants overproducing beta-phenethyl-alcohol in Saccharomyces cerevisiae.

p-Fluoro-DL-phenylalanine (PFP)-resistant mutants which produce a large amount of beta-phenethyl-alcohol, a rose-like flavor component, were isolated from the isogenic strains X2180-1A and X2180-1B of Saccharomyces cerevisiae. Cells of these mutants accumulated phenylalanine and tryptophan more than 3-fold times that of wild-type cells, while they accumulated less than half the tyrosine. The activity of prephenate dehydrogenase (PDG) (EC 1.3.1.12) was markedly decreased while that of 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase (EC 4.1.2.15) was increased. Genetic analysis revealed that the mutation occurred at the TYR1 locus, encoding PDG, and that the mutated TYR1 gene, try1-pfp, caused both PFP resistance and beta-phenethyl-alcohol overproduction. This was supported by molecular genetic studies with cloned tyr1-pfp DNA.

Alleles↗

PubMed1991

A mutated ARO4 gene for feedback-resistant DAHP synthase which causes both o-fluoro-DL-phenylalanine resistance and beta-phenethyl-alcohol overproduction in Saccharomyces cerevisiae.

o-Fluoro-DL-phenylalanine (OFP)-resistant mutants which overproduce beta-phenethyl-alcohol were isolated from a laboratory strain of Saccharomyces cerevisiae. Cells of one of the mutants accumulated tyrosine and phenylalanine 1.5-3 fold more than did wild-type cells. Its 3-deoxy-D-arabino-hepturosonate-7-phosphate (DAHP) synthase (EC 4.1.2.15), encoded by ARO4, was free from feedback inhibition by tyrosine. Genetic analysis revealed that the mutation was controlled by a single dominant gene, ARO4-OFP, encoding feedback-resistant DAHP synthase by tyrosine, and that this gene caused both the OFP resistance and beta-phenethyl-alcohol overproduction. This was supported by molecular genetic studies using cloned ARO4 both from the wild-type and its mutant strain.

3-Deoxy-7-Phosphoheptulonate Synthase↗