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Biomedical subjects

K Okazaki

Publications and source records attributed to K Okazaki.

At least 163 records · Page 9Linked to original sources
PubMed1998

Potentially virulent Newcastle disease viruses are maintained in migratory waterfowl populations.

Forty-seven Newcastle disease virus (NDV) strains isolated from fecal samples of waterfowls in Alaska and Siberia from 1991 to 1996 were analyzed for their virulence. None of the viruses formed plaques on MDBK cells in the absence of trypsin. Of these, 29 strains showed virulent character by the mean death time with the minimum lethal dose in chicken embryos comparable to velogenic NDV strains. Of the 29 strains, 11 were sequenced for their fusion protein (F) gene. The results showed that 5 of them contained a pair of dibasic amino acids at the cleavage site of the F, which is of a virulent type. The present results suggest that potentially virulent strains of NDV are maintained in migratory waterfowl populations in nature, and that some of those may be transmitted to domestic poultry and acquire pathogenicity during passages in chicken population.

Alaska↗
PubMed1998

[Acute angle-closure glaucoma following surgery for oral cancer].

A 60-year-old woman who had undergone surgery of oral cancer under general anesthesia developed an attack of acute angle-closure glaucoma the next morning. Her intraocular pressure decreased immediately by adequate treatments including surgical procedures (laser iridotomy and trabeculectomy), and her symptom improved. It is considered that this event was induced by several factors such as atropine given before and during general anesthesia, perioperative hypertension and anatomical abnormalities. However the definite cause of this event is unclear. We conclude that it is difficult to predict a glaucoma attack following surgery under general anesthesia, but this complication is an important ophthalmologic emergency. Immediate diagnosis and appropriate treatment should be done to prevent the grave prognosis.

Acute Disease↗
PubMed1997

Subtyping of D20S85 STR alleles by single-strand conformation polymorphism (SSCP) analysis.

During a population study of STR locus D20S85, we discovered two types of sequence variations by direct sequencing of the alleles: two transitions each of G to A and A to G occur in the 5' flanking region in the individuals possessing allele 6 and some of those possessing allele 7 [1]. Using single-strand conformation polymorphism (SSCP) analysis, we were able to distinguish two subtypes of allele 7 from each other. This analysis method enables rapid screening for STR alleles of the same length with different sequences, and should find application to other complex STR loci because of the practical advantage of simplicity in comparison to sequencing.

Forensic Medicine↗
PubMed1997

Enhanced expression of PP1 gamma 1, a catalytic subunit isoform of protein phosphatase type 1, in invasive ductal carcinoma of the breast.

Breast cancer is one of the most common malignancies of women. Assessing the biological parameters of malignant tumors may facilitate predictions of clinical outcome. The expression of the three catalytic subunits of protein phosphatase (PP) type 1, PP1 alpha, PP1 gamma 1 and PP1 delta, as well as the one catalytic subunit of PP type 2, PP2AC, were examined in ten cases of mammary dysplasia, ten cases of fibroadenoma and 12 cases of invasive ductal carcinoma, using immunohistochemical analysis. Moreover, we measured the S-phase fraction of the cell cycle for use as a marker value of cell growth, using flow cytometric analysis. The percentage of proliferating cells that stained positive with antisera against PP1 gamma 1 was significantly higher in invasive ductal carcinoma than in mammary dysplasia and fibroadenoma. Furthermore, invasive ductal carcinoma showed a markedly high number of tumor cells in the S-phase of the cell cycle, as compared to mammary dysplasia and fibroadenoma. Our results indicate that PP1 gamma 1 may be involved in the accelerated growth of malignant cells in breast tumors.

Adult↗
PubMed1997

Adaptation of equine herpesvirus 1 to unnatural host led to mutation of the gC resulting in increased susceptibility of the virus to heparin.

Heparin extensively inhibited infection of MDBK cells by equine herpesvirus 1 (EHV-1) strains adapted to bovine cells or hamsters, while the reagent merely reduced infectivity of strains passaged only in equine cells. The gC of two strains adapted to non-equine cells seemed to have higher affinity for heparin, although the reagent bound to both the gC and gB of all strains tested. Amino acid substitutions of the gC of the EHV-1 strains adapted to non-equine cells converged on the hydrophilic regions, amino acid residues 92 to 175, resulting in the glycoprotein becoming more cationic. These results indicate that these hydrophilic regions of the gC may be responsible for binding to heparin.

Adaptation, Physiological↗
PubMed1997

Gastric inflammatory fibroid polyps: endoscopic ultrasonographic analysis in comparison with the histology.

BACKGROUND: Histologic diagnosis of inflammatory fibroid polyp is usually difficult on routine endoscopic examinations. The aim of this study was to describe endoscopic ultrasonographic features of gastric inflammatory fibroid polyps. METHODS: Endoscopic ultrasonography was performed in 10 patients with gastric inflammatory fibroid polyps before resection. All lesions were resected by either endoscopic removal or gastrectomy and then confirmed histologically as inflammatory fibroid polyps. To evaluate the diagnostic value of endosonography, endoscopic ultrasonographic images of the lesions were analyzed and compared with resected specimens retrospectively. RESULTS: All lesions were located in the second and/or third sonographic layer of the gastric wall without involvement of the fourth layer. The most frequent endoscopic ultrasonographic features were an indistinct margin (90%), and a hypoechoic (80%), homogeneous (90%) echo pattern. Histologically, inflammatory fibroid polyps developed in the deep mucosa and/or submucosa by proliferation of fibrous tissue, but did not have a capsule. CONCLUSIONS: The characteristic endoscopic ultrasonographic attributes of gastric inflammatory fibroid polyps are indistinct margin, hypoechogenicity, homogeneous appearance, and location within the second and/or third layer. These findings correlate very closely to the histologic findings.

Adult↗
PubMed1997

Composite titanium dental implant fabricated by electro-discharge compaction.

An electro-discharge compaction (EDC) fabrication window was established for producing commercially pure porous titanium dental implants of 4 mm diameter and 7 mm length with a solid titanium cap. The optimum input energy was in the range of 0.58-0.87 kJ g-1 for a powder column of 0.500 g. Input energy greater than 0.58 kJ g-1 resulted in an implant torque strength exceeding 30 N-cm (the retaining screw tightening torque), while input energy greater than 0.72 kJ g-1 exceeded 46.7 N-cm torque strength (at this level the retaining screw failed prior to the implant). The integrity of the internally threaded hole and hexagonal head of the cap were maintained throughout the EDC process. The EDC process did not after the strength and/or microstructure of the components, and the bead-cap interface was stronger than the bead-bead interface. EDC implants produced within the aforementioned window have sufficient compressive strengths and other physical properties to meet the requirement for titanium dental implants.

Biocompatible Materials↗
PubMed1997

Hypoglycaemic and insulinotropic effects of a novel oral antidiabetic agent, (-)-N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine (A-4166).

1. (-)-N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine (A-4166), a novel oral hypoglycaemic agent is a non-sulphonylurea insulin secretagogue. 2. We investigated the insulin-releasing action and hypoglycaemic effect of A-4166 compared to sulphonylureas in vitro and in vivo. 3. A-4166 stimulated insulin secretion from rat freshly isolated pancreatic islets at concentrations from 3 x 10(-6) M to 3 x 10(-4) M in the presence of 2.8 mM glucose. There was no obvious difference in glucose dependency between the insulinotropic effect of A-4166 and that of glibenclamide, and no additive or synergistic effect was observed between these two drugs. 4. A-4166 displaced [3H]-glibenclamide bound to intact HIT-T15 cells in a concentration-dependent manner. The Ki value was 4.34 +/- 0.04 x 10(7) M, and the displacement potency of A-4166 was between that of glibenclamide and tolbutamide, being similar to that of gliclazide. 5. Inf fasted beagle dogs, A-4166 showed a dose-dependent hypoglycaemic effect after oral administration over the range 1 to 10 mg kg-1. The hypoglycaemic action of A-4166 showed an earlier onset and a shorter duration than that of sulphonylureas. 6. Simultaneous measurement of plasma insulin levels revealed that the hypoglycaemic effect of A-4166 was caused by a rapid-onset and brief burst of insulin secretion. 7. The pharmacokinetic profile of A-4166 was consistent with the changes of the blood glucose and plasma insulin levels. 8. Although the in vitro insulin-releasing effect of A-4166 was similar to that of sulphonylureas, its hypoglycaemic effect was more rapid and shorter-lasting, associated with rapid absorption and clearance. Thus, A-4166 may be useful in suppressing postprandial hyperglycaemia in patients with non-insulin-dependent diabetes mellitus.

Animals↗
PubMed1997

The ability of a new hypoglycaemic agent, A-4166, compared to sulphonylureas, to increase cytosolic Ca2+ in pancreatic beta-cells under metabolic inhibition.

1. N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine (A-4166) is a new non-sulphonylurea oral hypoglycaemic agent which stimulates insulin release by increasing cytosolic Ca2+ concentration ([Ca2+]i) in beta-cells. 2. We studied comparative effects of A-4166 and sulphonylureas on [Ca2+]i, measured by dual-wavelength fura-2 microfluorometry, in single rat pancreatic beta-cells under normal conditions and conditions where glucose metabolism was inhibited. 3. A glucokinase inhibitor, mannoheptulose (10 mM), a mitochondrial respiratory inhibitor, KCN (100 microM), and uncouplers, dinitrophenol (DNP, 50 microM) and carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP, 0.3 microM), were used to abolish glucose-induced increases in [Ca2+]i in a reversible manner. 4. Under control conditions, A-4166 was one order more potent than tolbutamide in increasing [Ca2+]i, and maximal responses were evoked by 30 microM A-4166 and 300 microM tolbutamide. These equipotent concentrations were employed for the comparative study where glucose metabolism was inhibited. 5. In the presence of mannoheptulose, [Ca2+]i responses to tolbutamide, but not those to A-4166, were attenuated in a reversible manner. 6. KCN, DNP and FCCP inhibited [Ca2+]i responses to tolbutamide to a much greater extent than those to A-4166. Responses to tolbutamide even at 3.3 times the equipotent concentration (1000 microM) were also markedly attenuated by these inhibitors. Responses evoked by another sulphonylurea, gliclazide, were inhibited by DNP to a larger extent than A-4166-induced responses. 7. The results indicate that A-4166 acts more effectively than sulphonylureas to increase [Ca2+]i in beta-cells during metabolic inhibition.

Animals↗
PubMed1997

Expression of a gene for uricase II (nodulin-35) in cotyledons of soybean plants.

A cDNA clone (URcot-35) was isolated from a soybean cotyledonary cDNA library using a cDNA clone (URnod-35) for nodule uricase II as a probe. URcot-35 was a 1,170-bp cDNA with an open reading frame that encoded a protein of putative 309 amino acids with a molecular mass of 35,137 Da. The nucleotide sequence of URcot-35 was identical to that of URnod-35. Expression of the URcot-35 gene in cotyledons was investigated by Northern dot-blot hybridization, by the reverse transcription-polymerase chain reaction with subsequent hybridization assays with the cDNA for nodule uricase II as a probe, and by immunoblotting analysis with a monoclonal antibody that was specific to nodule uricase II. The results suggested that the transcript of URcot-35 was present in developing cotyledons and that uricase II accumulated during the pod-filling stage. This is the first report of the isolation of cDNA for uricase II from non-symbiotic tissue and the results demonstrate that uricase II in soybean cotyledons is identical to that in soybean nodules.

Amino Acid Sequence↗
PubMed1997

Effect of a new hypoglycemic agent, A-4166 [(-)-N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine], on postprandial blood glucose excursion: comparison with voglibose and glibenclamide.

(-)-N-(trans-4-Isopropylcyclohexanecarbonyl)-D-phenylalanine (A-4166) is a new nonsulfonylurea hypoglycemic agent that lowers blood glucose by stimulating insulin release. In the present study, we examined the effects of A-4166, voglibose (an alpha-glucosidase inhibitor), and glibenclamide (a sulfonylurea) on the postprandial glycemic increase in rats with or without diabetes mellitus. Oral administration of A-4166 (25-100 mg/kg) dose-dependently decreased blood glucose with a rapid onset and short duration in normal rats. On the other hand, glibenclamide (1-4 mg/kg) showed a slower onset of its hypoglycemic action, and voglibose (0.2 mg/kg) had no effect. In the case of postprandial glucose excursion, the carbohydrate-induced increase in blood glucose was reduced by oral administration of either A-4166 or voglibose without causing sustained hypoglycemia in both normal and neonatal streptozotocin-induced diabetic rats. However, the efficacy of voglibose varied with the type of carbohydrate load. Glibenclamide produced a prolonged decrease in blood glucose without any appreciable effect on the initial glucose excursion. After sucrose loading, plasma insulin levels during the initial 1 h were significantly higher in A-4166-treated rats than in control rats, while voglibose completely inhibited the insulin response to sucrose. In glibenclamide-treated rats, an augmented insulin response was not seen. In conclusion, unlike other hypoglycemic agents, A-4166 suppresses postprandial glucose excursions by stimulating the early phase of insulin secretion.

Animals↗
PubMed1997

Synthesis and antimicrobial characteristics of 4,4'-(alpha,omega-polymethylenedithio)bis(1-alkylpyridinium iodide)s.

Bis-quaternary ammonium compounds (bis-QACs), 4,4'-(alpha,omega-polymethylenedithio)bis(1-alkylpyridinium iodide)s (4DTBP-m,n), which have 3 to 10 carbon atoms in the connecting methylene chain (m) and 8 to 18 carbon atoms of the N-alkyl chain (n), were synthesized. 4DTBP-6,12 exhibited a wide antimicrobial spectrum against gram-positive and gram-negative bacteria and fungi. The activity was stronger than those of N-dodecylpyridinium iodide (P-12), benzyldodecyldimethylammonium chloride and 2-(4-thiazolyl)benzimidazole. The bactericidal activities of 4DTBP-m,n were scarcely affected by the lengths of the alkyl chain and methylene chain. The bis-QAC that showed the highest activity was 4DTBP-6,8 (minimum inhibitory concentration (MIC) = 1.6 microM, minimum bactericidal concentration (MBC) = 2.6 microM), and its activity was about 10 times that of N-hexadecylpyridinium iodide (P-16), which was the most active in the P-n series. In addition, 4DTBP-6,12 showed a high bactericidal activity in the ranges of pH 5 to 8.5 and 10 to 40 degrees C, in contrast to mono-QACs. The bis-QACs synthesized in this study have excellent bactericidal properties.

Anti-Bacterial Agents↗