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Biomedical subjects

H Oku

Publications and source records attributed to H Oku.

At least 91 records · Page 5Linked to original sources
PubMed1997

[A case report of liaison psychiatry and open heart surgery in a patient with schizophrenia].

The surgical treatment for psychotics remains unsatisfactory because of the potential risk of the sudden death after operation. The perioperative care with an advice from the psychiatrist has been called the liaison psychiatry and considered important to prevent the postoperative psychiatric complication. A 47-year-old male patient who was diagnosed as the schizophrenia underwent aortic valve replacement with an aortic annular enlargement. The cardiac procedure in this patient was accomplished safely without postoperative complications related to the schizophrenia. When the liaison psychiatry is done adequately in the psychiatric patient who needs surgery, an operative procedure can be performed more safely with the minimum risk of the psychiatric complication.

Aortic Valve↗
PubMed1997

Retinal toxicity of nitric oxide released by administration of a nitric oxide donor in the albino rabbit.

PURPOSE: Nitric oxide (NO), which has been identified as an endothelium-derived relaxing factor, might be involved in regulation of retinal circulation and intraocular pressure. Recently, it was suggested that NO might also be related to neuronal excitotoxicity mediated by the N-methyl-D-aspartate receptor and to the pathologic changes induced by some kinds of uveitis. However, ocular toxicity of NO released by an NO donor has not been clearly demonstrated. In the current study, NO neurotoxicity in the retina was investigated. METHODS: S-nitroso-N-acetyl-DL-penicillamine (SNAP, 200 nmol) was injected into the vitreous of albino rabbits as an NO donor. The changes of retinal function were evaluated at 1, 2, and 3 hours and 1 and 4 weeks after SNAP injection, using electroretinogram and visual-evoked potentials. Histologic changes of the retina were also examined. RESULTS: Injection of SNAP reduced the a-wave amplitude. In contrast, the amplitudes of the oscillatory potentials were increased during the 3-hour observation period. Histologic examination showed vacuolar degeneration and loss of the nuclei of the photoreceptors. In the inner retina, some ganglion cells were lost, and cell density in the internal nuclear layer was decreased. CONCLUSION: Retinal toxicity of NO was demonstrated functionally and histologically, suggesting that NO may play a pathophysiologic role in retinal ischemia or in degenerative retinal diseases.

Animals↗
PubMed1996

Accumulation of 1-o-alkyl-2,3-diacylglycerols in cultured rat keratinocytes.

The present study was undertaken to identify the chemical structure of neutral lipid accumulated in cultured rat keratinocytes and to address their metabolism. Neutral lipid of similar mobility with alkyldiacylglycerol was isolated from cultured rat keratinocytes by thin layer chromatography. The long-chain diols derived from the neutral lipids were identified as 1-alkylglycerol based on the mass spectra of their nicotinylidene derivatives. Thus these neutral lipids were identified as 1-o-alkyl-2,3-diacylglycerols (ADAG). Addition of rat serum elevated the level of ADAG with increasing trend of linoleic acid concentration in this fraction. [14C]Acetate added to the confluent plates was incorporated into alkyl- and acyl-chains of ADAG with incubation in 24 h, and remained un-metabolized up to 72 h. This, however, is not the case for the label incorporation into phospholipid and triacylglycerol. Radioactivities of these two lipid fractions appeared to reach the maximum in 24 h, and thereafter decreased to 72 h with a similar decay curve. Incorporation of [14C]acetate into phospholipid and ADAG was significantly depressed, and that into triacylglycerol and free cholesterol was increased by the supplementation of the medium with rat serum. In concomitance with the accumulation of ADAG, the concentration of ethanolamine-plasmalogen increased in the cultured keratinocytes. The results of the present study first showed the elevated level of ether lipid synthesis in the proliferating primary culture of rat keratinocytes.

Acetates↗
PubMed1996

Age-related changes in branched-chain fatty acid concentration of the skin surface lipid from hairless mouse.

Age-related changes in branched chain fatty acid (BCFA) concentration were studied with the skin surface lipid from hairless mice. A large proportion of BCFA was present in the cholesterol ester (CE) and wax diester (WDE) fraction of the skin surface lipid from hairless mice. The concentration of iso-series BCFA was highest at infancy and decreased with advancing age in both CE and WDE fraction. The concentration of anteiso-series BCFA appeared to be constant throughout the experiment.

Age Factors↗
PubMed1996

Purification and characterization of hen oviduct alpha 1,2-mannosidase.

An alpha-mannosidase capable of hydrolyzing three Man alpha 1,2-residues from pyridylamine-(PA-) labeled Man9GlcNAc2 was purified from hen oviduct. The purity of the preparation was analyzed by PAGE; its molecular weight was 42,000 by SDS-PAGE or 50,000 by gel filtration. The pH optimum was 6.5. The enzyme was inactivated with EDTA; enzyme activity was restored by the addition of Ca2+. The enzyme activity was inhibited by 1-deoxymannojirimycin, but not by swainsonine. The substrate specificity of the purified enzyme was analyzed using PA-oligomannose-type sugar chains. When Man9GlcNAc2-PA was digested, Man alpha 1-6(Man alpha 1-2Man alpha 1-3)Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4Glc-NAc-PA was obtained as an end product, and the enzyme was incapable of hydrolyzing p-nitrophenyl alpha-D-mannoside and Man alpha 1,3- or Man alpha 1,6-residues. Judging from these characteristics, the enzyme was classified as a Man9-mannosidase or Golgi mannosidase I and speculated to participate in the processing or catabolism of glycoproteins.

1-Deoxynojirimycin↗
PubMed1996

Stereoconfiguration of anteiso-fatty biosynthesized from DL-isoleucine in rat skin.

Isoleucine (Ile) is a precursor for the biosynthesis of anteiso-fatty acids in rat skin, and among the four possible stereoisomers of Ile, L-Ile, and L-allo-Ile were selectively used for biosynthesis of anteiso-fatty acids. This study examined the optical rotation of anteiso-fatty acid derived from DL-Ile to ascertain its stereoconfiguration. Specific rotation of anteiso-fatty acid derived from DL-Ile favorably compared with that derived from L-Ile, suggesting the selective biosynthesis of the (S)-enantiomer of anteiso-fatty acid in rat skin.

Animals↗
PubMed1996

Dietary effects of corn oil, oleic acid, perilla oil, and evening [corrected] primrose oil on plasma and hepatic lipid level and atherosclerosis in Japanese quail.

To compare the atherogenecity of different fats and oils, a total of forty, 40-day-old male Japanese quails were fed one of the following diets for three months: basal diet (control), a diet-containing 15% corn oil (CO) and 2% cholesterol (CH), a diet-containing 15% oleic acid (OL) and 2% CH, a diet-containing 15% perilla oil (PE) and 2% CH, a diet-containing 15% evening [corrected] primrose oil (PR) and 2% CH. A higher plasma cholesterol concentration was found in the birds in the CO and OL groups, whereas the PE and PR groups showed a much lower level of plasma cholesterol than the CO and OL groups. In proportion to the increased plasma cholesterol, both CO and OL groups showed narrowing of the lumen of the ascending aorta and its large branches due to marked lipid-rich intimal thickening. Ultrastructural changes in the ascending aorta and its large branches were correlated with the degree of intimal thickening. The major foam cell types were macrophages and fibroblastic cells. The PE and PR groups showed the fewest lipid-rich intimal thickening lesions in their ascending aorta and its large branches. These findings suggest that the alpha-linolenic acid contained in perilla oil is less atherogenic than oleic and linoleic acid, and gamma-linolenic acid contained in evening [corrected] primrose oil has a tendency to decrease the plasma lipid level.

Animals↗
PubMed1996

Effect of dietary cholesterol on the activities of key enzymes of cholesterol metabolism in hyperlipidemia- and atherosclerosis-prone Japanese quail.

The hyperlipidemia- and atherosclerosis-prone (HAP) Japanese quail is a strain developed for the study of atherosclerosis by genetic selection from the commercially available (CA) Japanese quail. To delineate the characteristics of cholesterol metabolism in this strain, concentrations of serum lipids as well as hepatic enzyme activities were compared between HAP and CA quail. The hepatic enzymes studied are involved in the key step reaction in cholesterol metabolism: HMG-CoA reductase, ACAT, and cholesterol 7 alpha-hydroxylase. The animals were fed ad libitum with either 1% cholesterol or cholesterol-free semipurified diet for 28 days. Although a significant increase (p < 0.01) in serum cholesterol was observed in both strains on elapse of cholesterol feeding, formation of atheroma was seen exclusively in HAP quail of the cholesterol-fed group. The serum and liver cholesterol levels of HAP quail fed the cholesterol diet were significantly higher (p < 0.01) than those of CA quail. No significant differences were seen in the rate of cholesterol biosynthesis (HMG-CoA reductase activity), cholesterol ester formation (ACAT activity) and cholesterol catabolism (7 alpha-hydroxylase activity) between CA and HAP quail. Furthermore, the fecal excretions of acidic and neutral sterol showed no significant difference between strains. Although the formation of atheroma in HAP quail may be presumably due to the contribution of the marked increase in serum cholesterol level, the rate of cholesterol catabolism and synthesis in HAP quail compared well with those of CA quail. These observations suggest that the retarded rate of cholesterol biosynthesis or catabolism is not responsible for hypercholesterolemia in HAP quail.

Animals↗
PubMed1996

[Effect of a nitric oxide donor on optic nerve head circulation].

Recently the endothelium-derived relaxing factor was proved to be nitric oxide (NO) and it has been found to play an important role in the regulation of local blood flow. In this paper, we studied the effect of S-nitroso-N-acetyl-DL-penicillamine (SNAP), a NO donor, on the optic nerve head (ONH) circulation in rabbits, using a hydrogen gas clearance flowmeter etc. Intravitreal application of SNAP (20 nmol) increased the caliber of the retinal artery at the edge of the ONH 60 to 120 minutes later and capillary blood flow in the ONH 90 to 135 minutes later. A dose-response relation was found between 2 and 20 nmol. These changes were thought to be caused by NO produced from SNAP because they were inhibited by pretreatment with a NO trapping agent. Blood pressure and IOP were reduced 30 to 45 minutes later and 60 to 120 minutes later, respectively. It was considered that intravitreal injection of SNAP first reduced both the resistance of the ONH blood vessels and the perfusion pressure in the ONH and that the latter then rose, followed by an increase of the capillary blood flow in the ONH.

Animals↗
PubMed1996

[Simultaneous surgical revascularization for myocardial and peripheral vascular ischemia].

Patients with vascular disease has a high incidence of coexistence of coronary artery disease and patients with coronary artery disease can be associated with aortic or peripheral vascular occulusive lesions. Simultaneous coronary artery bypass grafting (CABG) and surgery for coexistent vascular lesions was performed in 13 patients from October 1991 until September 1995. Average number of graft for CABG was 3.5. For vascular lesions, fomoro-popliteal artery bypass was performed on four patients, aorto-both side iliac artery bypass using bifurcated prosthesis on there, aorto-iliac artery bypass on one, carotid endarterectomy on three and aorto-subclavian artery bypass on two patients. All patients survived without any major complications. There were no late death noted in the longest follow-up period of 42 months. Simultaneous surgical procedures for coronary arterial and other vascular lesions can be performed with acceptable risk and may offer physiological, psychological, social and echonomical advantages to avoid rehospitalization and repeated surgical interventions.

Aged↗
PubMed1995

1-O-alkyl-2,3-diacylglycerols in the skin surface lipids of the hairless mouse.

A neutral lipid class was isolated by thin-layer chromatography from the skin surface lipids of the hairless mouse. The fraction migrated faster than triglycerides and had a migration rate similar to that of diacyl alkanediols (diester wax). Upon deacylation, however, the long-chain diols were identified as 1-alkylglycerol ethers based on their chromatographic properties and on the mass spectra of their nicotinylidene derivatives. Thus, the skin lipid fraction was identified as 1-O-alkyl-diacylglycerol. The alkyl moieties were all saturated and even-numbered and ranged in chainlength from C16 to C22 with 1-O-hexadecylglycerol amounting to 34% of the total glycerol ether moieties. The fatty acids derived from this lipid fraction were mostly monoenoic with chainlengths ranging from C16 to C24. The major acyl component was eicosenoic acid (20:1) representing 61% of the total fatty acids.

Acylation↗
PubMed1995

Association of endothelin-1 with normal tension glaucoma: clinical and fundamental studies.

Impaired ocular blood flow is suspected to be one of the causes of normal tension glaucoma (NTG). We investigated whether endothelin (ET), a potent and continuous vasoacting peptide which was discovered recently, is associated with NTG. Plasma ET-1 levels of 52 patients with NTG but without systemic vascular or circulatory disorders were measured by radioimmunoassay, and were found to be significantly higher than those of 10 normal controls. The patients with NTG in the initial stage of visual field loss (Kosaki's classification) showed higher plasma ET-1 levels than those in the middle stage. These facts suggest that elevated plasma levels of ET-1 are correlated with NTG and its stages. We then studied the effects of ET-1 on rabbit eyes. Intravenous administration of ET-1 (10(-10) mol/kg) induced reductions in both intraocular pressure (IOP) and blood flow in the optic nerve head during three hours' observation, although it affected systemic blood pressure slightly and transiently. Blood flow in the choroid also decreased, but recovered at 90 minutes. Intravitreal injection of ET-1 (10(-5) M, 0.1 ml) also caused reductions in IOP (for 14 days) and in blood flow in the optic nerve head (during three hours' observation). Prolongation of VEP-N1 latency was observed for 14 days. These results indicate that ET-1 may be associated with NTG, especially with blood flow in the optic nerve head.

Aged↗
PubMed1995

Nucleus-cytoplasm interactions causing reproductive incompatibility between two populations of Tetranychus quercivorus Ehara et Gotoh (Acari: Tetranychidae).

Partial reproductive incompatibility between two local populations of Tetranychus quercivorus Ehara et Gotoh derived from Sapporo (43 degrees N) and Tsukuba (36 degrees N), Japan, was found. The incompatibility was unidirectional: the Sapporo female was incompatible with the Tsukuba males, which resulted in a low egg hatchability and strongly male-biased sex ratio, whereas the reciprocal cross was compatible and produced normal progeny with a female-biased sex ratio. To determine the genetic mechanism responsible for the incompatibility, crosses were made between the two populations over five to six filial generations as well as backcrosses. The results suggested that the incompatibility could be caused by an interaction between the cytoplasm from the Sapporo population and a single nuclear gene from the Tsukuba population. Compatibility was not restored when individuals of the Sapporo population were treated with antibiotics or high temperature, indicating a possibility that the cytoplasmic factors are cytoplasmically inherited elements such as mitochondria rather than microorganisms.

Animals↗
PubMed1995

Acetylenic compounds isolated from cultured cells of Asparagus officinalis.

Three new acetylenic compounds, compounds I, II and III were isolated from the cultured cells of Asparagus officinalis L. (Liliaceae) and their structures identified as 1-methoxy-4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]-benzene, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol and 4-[5-(4-hydroxyphenoxy)-3-penten-1-ynyl]phenol, respectively, from chemical and spectral analysis.

Acetylation↗
PubMed1995

Selective use of L-valine and L-isoleucine for the biosynthesis of branched-chain fatty acids in rat skin.

Iso- and anteiso-fatty acids are detected in more than trace amounts in rat skin surface lipid. The terminal portion of even carbon number iso- and anteiso-fatty acids are synthesized respectively from valine (Val) and isoleucine (Ile) by essentially the same reaction sequences established for straight chain fatty acids. This paper describes the stereospecific biosynthesis of these branched chain fatty acids (BCFAs) and alcohols (BCFALs) in rat skin. Dependence of the concentration of these BCFAs on dietary L-Val and L-Ile was studied. Concentrations of even carbon number iso- and anteiso-fatty acid increased respectively with dietary L-Val and L-Ile. The saturation dose appeared to be 2% for L-Val and 1% for L-Ile. Supplementation of the diet with 2% D-Val, however, did not affect the concentration of even carbon number iso-fatty acid in rat skin surface lipid despite a comparable serum Val level to that of the 2% L-Val group. A similar experiment using 1% DL-Ile found that L-isomer, but not D-isomer, in the circulation was used for the biosynthesis of anteiso-fatty acids. This view was applicable to the incorporation of D-Val and DL-Ile into related BCFALs.

Absorption↗
PubMed1995

[Two successful cases of total extracardiac right heart bypass].

We reported two successful cases of extracardiac total right heart bypass using 20 mm EPTFE conduit (modified total cavopulmonary connection). They were seven-year-old boy and nine-year-old girl. Both patients had complex heart disease including cyanosis, atrioventricular discordance. We selected this technique instead of modified Fontan or conventional total cavopulmonary connection because of safeness and easiness of surgery and the hemodynamic benefits. They don't have any restriction for their life postoperatively. We propose this technique as an alternative surgical option in candidates for a Fontan procedure or conventional total cavopulmonary connection.

Blood Vessel Prosthesis↗
PubMed1995

[Valvulo-and annuloplasty in correction of complete atrioventricular septal defect].

The surgical and postoperative long-term results were assessed in 55 patients undergoing correction of complete atrioventricular septal defects. The patients was divided into two groups according to mode of plasty of the atrioventricular valve: 45 patients in whom the cleft was closed in the earlier series, and 10 with trifoliated mitral valve, leaving the cleft unclosed in the later series. The early death occurred in 13 of 45 patients in the earlier series and none in the later series. During 11 years follow up period, mitral valve regurgitation of grade 3 and 4 was observed in 20% of the patients, respectively, in the earlier series. In contrast, grade 3 mitral regurgitation was detected in only one and no grade 4 regurgitation was present in the later series. Tricuspid valve regurgitation was irrelevant. In the later series, the diameter of the mitral valve was greater than the average value of Rowlatt's standard by 3.4 mm after partisioning the common atrioventricular valve into mitral and tricuspid components, and smaller than the normal by 0.2 mm, though the diameter was within the normal range after valvulo-and annuloplasty. On the other hand, the diameter of the tricuspid valve was also greater than the normal value by 1.7 mm after partisioning, however, that was smaller than the normal by 1.7 mm after valvulo-and annuloplasty, on the average. The diameter was smaller than the normal lower limit by one standard deviation in two patients. There was present neither mitral nor tricuspid stenosis in all on the post-operative hemodynamic study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗