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K Ozeki

Publications and source records attributed to K Ozeki.

At least 37 records · Page 2Linked to original sources
PubMed1998

Role of bile acids in duodenal migrating motor complexes in dogs.

Previous studies have suggested that enterohepatic circulation of bile acids is essential for regular cycling of duodenal migrating motor complexes (MMCs). The present study was an attempt to clarify the role of bile acids in the enterohepatic circulation system in initiating duodenal MMCs. Seven dogs underwent total external biliary diversion that resulted in the loss of MMCs originating from the duodenum. Sodium ursodeoxycholate (6 mg/kg/hr) was then given either through the portal vein or a peripheral vein, and motility of the gastrointestinal tract was serially recorded. When sodium ursodeoxycholate was given either through the portal vein or a peripheral vein during external biliary diversion, duodenal MMCs restarted. The cyclic change in plasma motilin levels during an MMC cycle as induced by sodium ursodeoxycholate was almost the same as in a normal MMC cycle. Total bile acid concentration in the portal vein changed cyclically with MMC cycles when bile flow was intact but did not change cyclically with MMC cycles restarted by intravenous bile salt infusion. Bile acid stimulation of putative receptors existing between the portal vein and intrahepatic bile ducts may be involved in initiating normal duodenal MMC cycles.

Animals↗
PubMed1998

The effect of hyperbaric oxygen treatment on bone tissue reactions to c.p. titanium implants placed in free autogenous bone grafts. A histomorphometric study in the rabbit mandible.

This study aimed to investigate the effect of hyperbaric oxygen (HBO) therapy on the tissue reactions to commercially pure (c.p.) titanium implants placed in free autogenous bone graft by a 1-stage procedure. Eighty c.p. titanium implants were placed in the bone grafted from iliac crest to bilateral mandible of 40 Japanese white rabbits without tapping. Twenty rabbits underwent daily a HBO treatment for 60 min under 2.4 ATA during 20 consecutive days and the other untreated 20 rabbits served as controls. The implants with surrounding bone tissue were retrieved 20, 30, 60, 90 and 120 days after surgery, fixated, dehydrated and embedded in resin. About 20 microns thick ground sections were prepared prior to microscopical observations. The bone area and the bone-to-implant contact inside the threads were calculated separately in the grafted bone and in the host bone for each implant. After 30 and up to 120 days, the HBO treated group showed more bone-to-implant contacts in the grafted bone as compared to the non-HBO treated group. In the host bone there were no differences observed between HBO and non-HBO treated groups. This study indicated that HBO treatment was beneficial for the tissue incorporation of c.p. titanium implants when placed immediately in free autogenous bone grafts.

Animals↗
PubMed1997

A comparative study of removal torque of endosseous implants in the fibula, iliac crest and scapula of cadavers: preliminary report.

This study was undertaken to compare removal torque of endosseous implants in the fibula, iliac crest and scapula of cadavers. The fibulae, iliac crests and scapulae were harvested from the right side of 5 formalin-preserved cadavers. Endosseous implants (Brånemark System) were placed at 3 points of each bone. The removal torque of the implant was measured by a torque gauge manometer (Tohnichi 15 BTG-N). After measurement of the removal torque, the bone was cut at each implant site. The thicknesses of cortical and total bone were measured. The mean removal torques were 46.3 N cm in the fibulae, 15.2 N cm in the iliac crests and 21.4 N cm in the scapulae. There was a statistically significant difference in mean removal torque between the three bones. The total bone thicknesses were 11.7 mm in the fibulae, 9.9 mm in the iliac crests and 8.2 mm in the scapulae. The cortical bone thicknesses were 5.0 mm in the fibulae, 1.6 mm in the iliac crests and 1.8 mm in the scapulae. Significant correlation between the removal torque and the cortical bone thickness was found. However there was no significant correlation between the removal torque and the total bone thickness. In conclusion, the implants inserted in the fibulae showed the highest removal torques as compared to the ones inserted in the iliac crests and the scapulae. Moreover the removal torque was related to the thickness of the cortical bone in the implant sites.

Adult↗
PubMed1996

Cyclic motor activity of the gallbladder maintained in a pylorus-preserving gastrectomy in dogs.

The gallbladder has cyclic motor activity (CMA), which is impaired after a conventional gastrectomy. We conducted experiments to determine whether or not a pylorus-preserving gastrectomy (PPG) could maintain gallbladder CMA. Six strain gauge force transducers were implanted into the gastrointestinal tract and gallbladder of six dogs, respectively. The motor activity of the gastrointestinal tract and gallbladder was recorded as a control. PPG was then carried out. The phasic contractions of the gallbladder, which were correlated with the antral contractions in the control state, were synchronized with contractions of the pylorus after PPG. Intravenous administration of CCK-OP (40 ng/kg) induced phasic contractions of the gallbladder at 4.6 +/- 0.2 c/min in 3 of the 6 days with gastric contractions. After PPG, the gallbladder had phasic contractions (4.5 +/- 0.2 c/m), which were synchronized with the contractions of the pylorus in all dogs regardless of the contractions in the remnant stomach. These findings suggest that gallbladder CMa has a closer relationship with the CMA of the pylorus than with the remnant stomach after PPG. Thus, a preservation of the pylorus at the time of gastric surgery will help in maintaining gallbladder function and coordination with the remnant stomach.

Animals↗
PubMed1996

Effects of green tea and tea catechins on the development of mammary gland.

To find whether green tea and tea catechins have effects on the development of mammary glands, virgin DDD mice were fed on diets containing green tea and tea catechins. The degree of mammary gland development was examined by duct-alveolar growth and DNA content. The results indicated that green tea, but not tea catechins, has a growth-promoting effect on mammary gland development.

Animals↗
PubMed1996

Construction of a promoter probe vector autonomously maintained in Aspergillus and characterization of promoter regions derived from A. niger and A. oryzae genomes.

We used a plasmid carrying a sequence for autonomous maintenance in Aspergillus (AMA1) and the E. coli uidA gene as a reporter gene to search the A. oryzae and A. niger genomes for DNA fragments having strong promoter activity. Beta-glucuronidase (GUS)-producing A. oryzae transformants containing the No. 8AN derived from A. niger, or the No. 9AO derived from A. oryzae, were constitutive for the expression of the uidA gene when cultivated in the presence of a variety of carbon and nitrogen sources. When the GUS-producing transformants were grown in liquid culture, the No. 8AN showed an increase of approximately 3-fold in GUS activity compared to the amyB (alpha-amylase encoding gene) promoter. There was also a corresponding increase in the amount of GUS gene-specific mRNA. When these transformants were grown as rice-koji, the No. 8AN showed an increase of approximately 6-fold compared to the amyB promoter, and the amount of GUS protein produced also increased. These strong promoter regions might be applicable to the production of other heterologous proteins in Aspergillus species.

Aspergillus niger↗
PubMed1995

Effect of celiac and superior mesenteric ganglionectomy on fasted canine colonic motor activity.

The role played by extrinsic nerves in colonic motor activity and motor coordination between the small intestine and the colon in the fasting state was investigated in a canine model. To evaluate motor activity before and after celiac and superior mesenteric ganglionectomy (CSMG), seven strain gauge force transducers were implanted in the small and large bowels of five dogs. No significant differences were observed in the frequency, duration, cycle, or migration time of bursts of contractions from the colon (BCC), or in the duration of the quiescent state before and after CSMG. When small intestinal phase III activity reached the ileocecal junction before and after CSMG, a characteristic contractile pattern, namely, small intestinal phase III activity followed by BCC, was observed at the ileocecal junction. Before and after CSMG, 84% and 83% of the small intestinal phase III activity, respectively, was transmitted to the colon as BCC after reaching the ileocecal junction. However, only 19% and 18% of BCC before and after CSMG, respectively, followed small intestinal phase III activity. These results led us to conclude that the extrinsic nerves exert little effect on fasting colonic motor activity and motor transmission from the small intestine to the colon.

Animals↗
PubMed1995

A method for the re-isolation of an autonomously replicating plasmid from Aspergillus transformants.

An autonomously replicating plasmid is expected to increase the frequency of Aspergillus transformation. To construct this type of plasmid, we developed a rapid method of re-isolating autonomously replicating plasmids from Aspergillus transformants. Transformants grown in MM medium under selective pressure for 1-2 days were converted to protoplasts with a cell wall lytic enzyme (e.g. Yatalase). The protoplasts were lysed with phenol/chloroform followed by precipitation with ethanol. The total DNA was treated with RNaseA, re-precipitated with PEG, and then used to transform E. coli. These re-isolated plasmids were mainly the plasmid monomer.

Aspergillus↗
PubMed1994

Transformation of intact Aspergillus niger by electroporation.

A new rapid transformation system for Aspergillus niger that uses electroporation to render intact germinating conidia permeable to DNA is described. The transformant colonies appeared earlier than transformants obtained by the protoplast-forming method. Without pretreatment of the conidia the transformation frequencies were 1.2 colonies per micrograms of integrative vector and 100 colonies per micrograms of plasmid DNA. When the conidia were treated with a dilute solution of fungal cell wall lytic enzyme, the frequency of transformation was increased by approx. 2-fold when using two vectors. Southern blot analysis of genomic DNA and restriction endonuclease-digested DNA from a random sample of transformants showed homologous and nonhomologous integration of the integrative vector into the genome, as is also observed with the protoplast-forming method. In transformation with the plasmid vector, the transformant DNA was shown to be mostly maintained in free form with minimal integration into the chromosome when transformed by either intact electroporation or the conventional method.

Aspergillus niger↗
PubMed1994

[Ileocecal syndrome].

Explore the source record for details and available documents.

Gastrointestinal Motility↗
PubMed1992

Enterohepatic circulation is essential for regular cycling of duodenal migrating motor complexes in dogs.

The role of enterohepatic circulation and specific bile acids in the initiation and caudad migration of duodenal migrating motor complexes (MMCs) was investigated in conscious dogs. All dogs had spontaneous duodenal MMCs that migrated to the terminal ileum when bile flow was intact. During the first 3 days after total external biliary diversion, no MMCs originated in the duodenum. Instead, all MMCs originated in the jejunum and migrated to the ileum. During the next 4 days of total external biliary diversion, 81% of the MMCs originated in the jejunum and 19% in the duodenum. When normal bile flow was restored after 9 days of total external biliary diversion, regular duodenal MMCs resumed after a delay of 126 +/- 27 minutes. Perfusion of individual bile acids or dogs' own bile, but not saline or alkaline solution, into the duodenum or perfusion of dogs' own bile directly into the ileum during total external biliary diversion restarted duodenal MMCs with a time lag of about 2 hours. The authors conclude that intact enterohepatic circulation is essential for the initiation of regular duodenal MMCs.

Animals↗
PubMed1991

Cloning and nucleotide sequence of the genomic ribonuclease T2 gene (rntB) from Aspergillus oryzae.

Using synthetic oligonucleotide probes, we have cloned a genomic DNA sequence encoding a ribonuclease (RNase) T2 gene (rntB) from Aspergillus oryzae on a 4.8 kb HindIII fragment. DNA sequence analysis of the RNase T2 revealed the following: (1) The gene is arranged as five exons and four introns; (2) The deduced amino acid sequence contains 239 amino acid residues of the mature enzyme. In addition, there exist 17 amino acid residues thought to be a signal peptide sequence at the N-terminus and 20 amino acid residues at the C-terminus; (3) The nucleotide sequence of the rntB gene is homologous to those of the RNase Rh gene from Rhizopus niveus and the S2 stylar glycoprotein gene of Nicotiana alata with degree of about 51% and 47%, respectively; (4) A. oryzae and A. nidulans transformed with the cloned rntB gene had much higher ribonuclease T2 activity than wild-type strains.

Amino Acid Sequence↗
PubMed1991

Properties of hydroxyapatite-coated Ti-6Al-4V alloy produced by the ion-plating method.

To improvement the brittleness of hydroxyapatite (HAp) coated on titanium alloy (Ti-6Al-4V), a thin ceramic layer was formed by means of the RF ion-plating method. The alloy substrates were coated with HAp at 1, 3 or 5 microns thickness and heat-treated at 500 degrees C for 4 hours. Properties of HAp-coated alloy were evaluated by characterization of the ceramic films both before and after heat-treatment, as well as by bending, electrochemical and dissolution tests. HAp-coated film had a slightly higher Ca/P ratio than the original material and was stoichiometrically Ca10(PO4)6(OH)2 by EPMA analysis. HAp was mainly recognized crystallographically by XRD analysis of the films after heat treatment, though it was hardly recognized on before heat-treatment film. These coated materials had a residual strain ranging from 0.3 to 0.7% without causing cracks in the HAp films with the three-point bend testing. Electrochemically, it was confirmed that the corrosion resistance of the Ti alloy was improved by any coating process. The amounts of Ca released from HAp coated film in 0.9% NaCl solution tended to increase with films that were 3 and 5 microns in thickness, but there were no significant differences in Ca released from film before and after heat treatment.

Aluminum Oxide↗
PubMed1989

Studies on antiallergy agents. III. Synthesis of 2-anilino-1,6-dihydro-6-oxo-5-pyrimidinecarboxylic acids and related compounds.

A series of 2-anilino-1,6-dihydro-6-oxo-5-pyrimidinecarboxylic acids with various substituents was synthesized and evaluated in the rat passive cutaneous anaphylaxis test for antiallergic activity. High activity by intraperitoneal and oral administrations was observed for the 3-trifluoromethyl and 2-alkoxyanilino derivatives (64, 79, 81, 82 and 85). Structure-activity relationships are discussed.

Aniline Compounds↗