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H Okuyama

Publications and source records attributed to H Okuyama.

At least 37 records · Page 2Linked to original sources
PubMed2001

Temporal and spatial localization of osteoclasts in colonies from embryonic stem cells.

Osteoclasts are hematopoietic cells essential for bone resorption. To understand the process of osteoclastogenesis, we have developed a culture system that employs a stromal cell line, in which differentiation of osteoclasts from single embryonic stem (ES) cells occurs. This culture, which did not require any cell passaging or other manipulations, enabled us to investigate the temporal and spatial localization of the osteoclast lineage in the colonies formed from ES cells. Cells expressing tartrate-resistant acid phosphatase, a specific marker of the osteoclast lineage, were first detected on day 8, and subsequently became localized at the periphery of colonies and matured into multinucleated cells to resorb bone. Addition of macrophage colony-stimulating factor and osteoprotegerin-ligand, which are produced by stromal cells, promoted osteoclastogenesis in whole colonies, indicating that the location and maintenance of mature osteoclasts as well as the growth and differentiation of osteoclast precursors are regulated by these two factors.

Animals↗
PubMed2001

Change of oligosaccharides of rat brain microsomes depending on dietary fatty acids and learning task.

We have analyzed oligosaccharide chains in brain microsomes of rats fed an n-3 polyunsaturated fatty acid-deficient (safflower oil group; S group) or -rich (perilla oil group; P group) diet before and after brightness-discrimination learning tasks. The amount of concanavalin A-binding sites (mainly mannoside) of the brain microsomes was found to be significantly less in the S group than the P group before the learning task. Detailed analysis of glycoprotein glycans demonstrated that high mannose type oligosaccharides were dominant in brain microsomes before the learning task in both dietary groups, whereas multiantennary complex-type oligosaccharides became dominant after the learning task and especially a tetra-antennary glycan, that had a core structure of the glycan of neural cell adhesion molecule, was more increased in the S-group than the P group. When polysialylated glycans were analyzed on serotonin-conjugated HPLC column, the glycans in the S-group microsomes before the learning task contained larger amount of higher affinity-polysialylated glycans to serotonin column than those in the P-group, and also contained larger amount of phosphoglycans that showed also high affinity to serotonin column than the P-group. Removal of mannoside from microsomes by alpha-mannosidase-treatment changed the membrane surface physical property, especially permittivity, as revealed by analysis of the interaction with 1-anilinonaphthalene-8-sulfonate. These results suggest that high mannose content and several multiantennary glycans including polysialylated and phospho-glycans were changed by dietary n-3 fatty acid deficiency and learning task in rat brain microsomal glycoproteins and that these changes may affect membrane functions through changes of membrane surface physical properties and reactivity against serotonin.

Animals↗
PubMed2001

Assignment of Pseudomonas sp. strain E-3 to Pseudomonas psychrophila sp. nov., a new facultatively psychrophilic bacterium.

A facultatively psychrophilic bacterium, previously described as Pseudomonas sp. strain E-3, has been reassigned by phenotypic characterization, chemotaxonomic analysis, DNA-DNA hybridization, and 16S rRNA gene phylogenetic analysis. The organism was a gram-negative, aerobic. straight rod with polar flagella. It was catalase positive and oxidase positive, able to grow at -1 degree C but not at 40 degree C, and produced acid from D-glucose under aerobic conditions. The major isoprenoid quinone was ubiquinone-9, and the DNA G + C content was 57.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the bacterium is a member of the genus Pseudomonas and was closest to Pseudomonas fragi. Determination of the DNA-DNA relatedness between strain E-3 and P. fragi revealed too low a level of homology (47.9%-51.3%) to identify them as the same species. On the basis of phenotypic characteristics, phylogenetic analysis, and DNA-DNA relatedness data, it is concluded that strain E-3 represents an individual species. Accordingly, the name Pseudomonas psychrophila is proposed. The type strain is E-3T (= JCM 10889).

Base Composition↗
PubMed2001

Effect of dietary oils enriched with n-3 fatty acids on survival of mice.

Female mice were fed a conventional diet, shifted at 119 days of age to a diet supplemented with 10 wt % lard (Lar), high-linoleic (n-6) safflower oil (Saf), rapeseed oil (low-erucic, Rap), high-alpha-linolenic (n-3) perilla oil (Per) or a mixture (1:9) of ethyl docosahexaenoate (n-3) and soybean oil (DHA/Soy). Weight gain was less in the Per group than in the other groups at 497 days of age. In the Rap group, proteinuria was more severe than in the Saf, Per and DHA/Soy group, and hepatic triacylglycerol accumulation was greater than in the other groups. The mean survival time of the DHA/Soy group (753 days) was significantly longer than in the Lar group (672 days) and Saf group (689 days); the differences among other groups (e.g., 701 days in the Per group and 712 days in the Rap group) were not statistically significant. Although DHA is more susceptible to auto-oxidation than other major fatty acids in the air, an oil containing DHA was found to increase the survival of mice. Rapeseed oil that decreases the survival time of SHRSP rats was found to be safe in the mouse strain used in this study when survival was an end point.

Journal Article↗
PubMed2001

End-tidal carbon monoxide is predictive for neonatal non-hemolytic hyperbilirubinemia.

BACKGROUND: The aim of the present study was to evaluate the value of an end-tidal carbon monoxide corrected for inhaled carbon monoxide concentration (ETCOc) at the early neonatal period. The value would be useful for predicting subsequent hyperbilirubinemia in non-hemolytic full-term infants. METHODS: The ETCOc levels were measured every 6 h during the first 72 h of life in healthy, full-term, non-hemolytic, newborn Japanese infants using a breath carbon monoxide analyzer. The ETCOc levels in hyperbilirubinemic infants were compared with those in non-hyperbilirubinemic infants. Hyperbilirubinemia was defined as the level of the peak total serum bilirubin concentration (TBC) greater than or equal to 257 micromol/L (15.0 mg/dL). The ETCOc measurement for predicting subsequent hyperbilirubinemia was evaluated with a receiver-operating characteristic (ROC) curve. RESULTS: Fifty-one infants were enrolled in the study. Seven of the 51 infants developed hyperbilirubinemia. The ETCOc levels in non-hyperbilirubinemic infants were decreased in the first 72 h after birth. However, those in the hyperbilirubinemic infants were not decreased significantly, and were higher than those in non-hyperbilirubinemic infants at 42, 48, 54 and 66 h of age. The ETCOc level at 42 h of age was the most predictive of subsequent hyperbilirubinemia by ROC analysis. At the cut-off level of 1.8 microL/L (p.p.m.), the sensitivity, the specificity, the positive predictive value and negative predictive value were 86, 80, 40 and 97%, respectively. CONCLUSION: Increased ETCOc level in the early neonatal period is associated with subsequent hyperbilirubinemia, even in infants without hemolytic disease. The ETCOc measurement may be useful as a screening test for predicting hyperbilirubinemia without hemolytic diseases.

Breath Tests↗
PubMed2001

Histopathologic changes after tracheobronchial reconstruction with costal cartilage graft for congenital tracheal stenosis.

BACKGROUND/PURPOSE: Congenital tracheal stenosis is an uncommon, life-threatening condition. Recently, tracheoplasty using costal cartilage grafts to enlarge the lumen was used successfully in such cases. In this study, we evaluated postoperative changes of costal cartilage grafts after tracheoplasty. METHODS: Costal cartilage patch tracheoplasty was used for surgical correction of long-segment congenital tracheal stenosis in 18 infants. Six patients whose tracheal specimens were obtained at autopsy are included in this study. The mean age at the time of repair was 4.8 months, and the mean period after operation was 7.5 months. Cartilage graft survival and epithelialization of inner layer was evaluated in each case. RESULTS: The mean width and length of grafts was 6.3 x 35 mm at operation and 4.0 x 22 mm at autopsy. The graft size was diminished gradually after operation and was replaced completely by mature scar tissue 2 years after operation. However, diameter of the reconstructed site was not reduced. Reepithelialization of the graft site with ciliated columnar epithelium was found in every case. Chondrocyte numbers were reduced and remaining cartilage was rather eosinophilic, suggesting that the degenerative process was ongoing in the graft. CONCLUSIONS: The costal cartilage grafts established a functional tracheal lumen, and reepithelialization with ciliated columnar epithelium was found at the graft site. The costal cartilage grafts continues to be an important option as graft material for tracheal reconstruction in infants with long segment congenital tracheal stenosis.

Cartilage↗
PubMed2001

Characterization of the gene encoding the beta-lactamase of the psychrophilic marine bacterium Moritella marina strain MP-1.

The beta-lactamase gene (mbla) of the psychrophilic marine bacterium Moritella marina strain MP-1 was identified in a previously isolated genomic DNA fragment and it was expressed in Escherichia coli cells. The mbla gene encoded a protein consisting of 287 amino acid residues. Its predicted amino acid sequence showed approximately 50% identity with that of a number of class A beta-lactamases, especially with that of CARB/PSE type of beta-lactamases (carbenicillinases). E. coli transformed with the plasmid containing mbla grew on an ampicillin-containing plate at 37 degrees C but not at 42 degrees C, suggesting that the beta-lactamase of this bacterium is heat-labile.

Amino Acid Sequence↗
PubMed2001

Simultaneous detection of cholyl adenylate and coenzyme A thioester utilizing liquid chromatography/electrospray ionization mass spectrometry.

It has been proposed that acyl adenylate is first formed during activation of the carboxy group into the acyl CoA thioester, an intermediate in the formation of amino acid conjugates. Acyl CoA synthetases may be responsible for this acyl adenylate formation. Recently, we hypothesized the preferential formation of cholic acid adenylate, a major bile acid, preceding production of the corresponding CoA thioester in incubations with rat liver microsomal fractions. To verify this biosynthetic mechanism, monitoring of the incubation mixture of acyl adenylate together with both substrate and acyl CoA thioester is needed. We have developed a detection method for the simultaneous detection of these cholic acid derivatives utilizing liquid chromatography/electrospray ionization mass spectrometry. The CoA thioester of cholic acid forms a chelation complex with the divalent cations remaining on the silica gel packed into the analytical column. Both the addition of a chelating agent, such as EDTA, to the mobile phase and an adjustment of the mobile phase pH to a weak alkaline effectively removed such chelate formation, producing a sharp CoA thioester peak. For a simultaneous mass spectrometric analysis of cholic acid, the corresponding adenylate and CoA thioester, the combined use of a 300 A particle diameter ODS column and 20 mM ammonium acetate buffer (pH 9.0)/2-propanol/acetonitrile as the mobile phase have been proved to be preferable. To avoid any degradation of the chemically unstable adenylate produced in the incubation, we employed a direct injection of the sample onto a preconcentration column. The obtained results indicated a high sensitivity of this method.

Adenosine Monophosphate↗
PubMed2001

[In vitro induction of differentiation from embryonic stem cells: looking forward to regenerative medicine].

Embryonic stem (ES) cells are pluripotential cells, and enable us to study mechanisms of cell differentiation. Gene disruption of ES cells by homologous recombination is to be clear the function of targeted genes. Recently, it has been reported that bone marrow hematopoietic stem cells have a potential to differentiate into neuronal cell, muscle cell, liver cell, epidermal cell, and also epithelial cell lineages. Moreover, cloned animals from somatic cell nuclei were produced. Here, we show osteoclastogenesis, and endothelial cell-genesis from single ES cell, and discuss the possibility for organogenesis in vitro. Furthermore, we would like to summon to understand usefulness and dangerousness of the regenerative medicine.

Animals↗
PubMed2001

Reversibility of n-3 fatty acid deficiency-induced alterations of learning behavior in the rat: level of n-6 fatty acids as another critical factor.

Rats fed a semipurified diet supplemented with 3% (w/w) safflower oil [Saf, n-3 fatty acid deficient, high linoleic acid (18:2n-6)] through two generations exhibit decreased correct response ratios in a brightness-discrimination learning test compared with rats fed 3% perilla oil [Per, high alpha-linolenic acid (18:3n-3)]. This is associated with a decreased DHA (22:6n-3)-to-arachidonic acid (20:4n-6) ratio in brain lipids. In the first set of experiments, dietary oil was shifted from Saf to a mixture of 2.4% safflower oil plus 0.6% DHA after weaning (Saf-DHA), but all parameters measured in the learning test were essentially unchanged. Brain 22:6n-3 content of the Saf-DHA group reached that of the Per group but the levels of 20:4n-6 and docosatetraenoic acid (22:4n-6) did not decrease to those of the Per group at the start of the test. In the second set of experiments, dietary oil was shifted to a mixture of 0.6% safflower oil plus 1.2% oleic acid (OA) plus 1.2% DHA (Saf-OA-DHA group) with 18:2n-6 content comparable to that of the Per group. The Saf-OA-DHA group exhibited a learning performance similar to that of the Per group; brain 22:6n-3, 20:4n-6, and 22:4n-6 contents were also comparable to those of the Per group. These results indicate that the altered learning behavior associated with a long-term n-3 fatty acid deficiency is reversed by supplementing 22:6n-3 after weaning, when the levels of competing n-6 fatty acids in the diet and brain lipids are limited.

Aging↗
PubMed2001

[Thrombosis of the abdominal aorta in a patient with nephrotic syndrome].

Nephrotic syndrome frequently causes thromboembolic complications in veins. Arterial thrombosis, however, is relatively rare. We report the case of a 47-year-old male with nephrotic syndrome complicated with abdominal aortic thrombosis. The patient complained of pain in the bilateral lower extremities 2 weeks after the development of nephrotic syndrome. The aortogram revealed complete occlusion of the abdominal aorta just below the origin of the inferior mesenteric artery. Necrosis of the legs extended rapidly, and he eventually lost his legs. Among various predisposing factors, hypercoagulability associated with nephrotic syndrome seemed to be responsible for the development of thrombosis. Thrombotic complications are sometimes serious in the nephrotic patient. Assessment for the risk factors is required to warrant prophylactic anticoagulation.

Amputation, Surgical↗
PubMed2000

Diurnal rhythms of retinal phospholipid synthetic enzymes are retained but their activities are decreased in rats under alpha-linolenic acid deficiency.

Rats fed a safflower oil (alpha-linolenic acid (ALNA)-deficient) diet over the course of two generations had significantly decreased docosahexaenoic acid (22:6n-3) and increased docosapentaenoic acid (22:5n-6) contents in the major retinal phospholipids such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS) when compared with those fed a perilla oil (ALNA-sufficient) diet, but the compositions of phosphatidylinositol acyl chains were relatively unaffected. The contents of individual phospholipids in the retina were essentially the same for the two dietary groups. The activities of the rate-limiting enzymes in the de novo synthesis of PC and PE, CTP:phosphocholine cytidylyltransferase (CT), and CTP:phosphoethanolamine cytidylyltransferase (ET), respectively, were measured in the retinas excised at 5:00, 9:00, 13:00, and 17:00 h from rats adapted to a 24-h cycle with lights on from 7:00 to 19:00 h. Both enzymes exhibited significant diurnal rhythms with the lowest activities at 5:00 h and gradually increasing activities following exposure of the rats to light; the maximum activities were at 13:00 h for CT and 17:00 h for ET. The diurnal rhythms were not significantly affected by the above-mentioned diets. However, both enzyme activities at each collection time point were significantly lower in the safflower oil group than in the perilla oil group. These results suggest that retinal phospholipid turnover associated with shedding, phagocytosis, and resynthesis of the rod outer segments is limited by ALNA deficiency.

Animals↗
PubMed2000

Spontaneous chirality in simple systems

Two simple examples of spontaneous chiral symmetry breaking are presented. The first is close-packed cylindrically confined spheres. As the cylinder diameter is varied, one obtains a variety of chiral phases. The second example involves unconfined dipolar particles with an isotropic attraction, which also exhibits chiral ground states. We speculate that a dilute magnetorheological fluid film, with the addition of smaller particles to provide an attractive entropic interaction, will exhibit a chiral columnar ground state.

Journal Article↗
PubMed2000

Dietary n-3 fatty acid deficiency decreases nerve growth factor content in rat hippocampus.

Dietary deprivation of alpha-linolenic acid (n-3) through two generations has been shown to lower performance in an operant-type brightness-discrimination learning test in rats. Here, we examined a possible correlation between nerve growth factor (NGF) content and n-3 fatty acid status in the brain. Female rats were fed a semipurified diet supplemented with safflower oil (n-3 fatty acid-deficient) and their offsprings were fed a diet supplemented with either 3% safflower oil (Saf group) or a mixture of 2.4% safflower oil plus 0.6% ethyl eicosapentaenoate (Saf+EPA group) after weaning. The brain docosahexaenoic acid (22:6n-3, DHA) content in the Saf group was less than half of that in the Per group fed a diet supplemented with 3% perilla oil (n-3 fatty acid-sufficient) throughout the duration of the experiment. The DHA level of the Saf+EPA group was restored to the level of the Per group. However, the NGF contents in the hippocampus of the Saf and Saf+EPA groups were half that of the Per group. In the piriform cortex, the NGF content tended to be higher in the Saf and Saf+EPA groups than in the Per group. These results indicate that dietary n-3 fatty acid deficiency and restoration affect NGF levels differently among different brain regions.

Animals↗
PubMed2000

Dietary docosahexaenoic acid ameliorates, but rapeseed oil and safflower oil accelerate renal injury in stroke-prone spontaneously hypertensive rats as compared with soybean oil, which is associated with expression for renal transforming growth factor-beta, fibronectin and renin.

We have noted that n-3 fatty acid-rich oils, such as fish oil, perilla oil and flaxseed oil as well as ethyl docosahexaenoate (DHA) prolonged the survival time of stroke-prone spontaneously hypertensive rats (SHRSP) rats by approximately 10% as compared with linoleate (n-6)-rich safflower oil. Rapeseed oil with a relatively low n-6/n-3 ratio unusually shortened the survival time by approximately 40%, suggesting the presence of minor components unfavorable to SHRSP rats. This study examined the effects of dietary oils and DHA on renal injury and gene expression related to renal injury in SHRSP rats. Rats fed rapeseed oil- and safflower oil-supplemented diets developed more severe proteinuria than those fed soybean oil-supplemented diet used as a control, but there were no significant differences in blood pressure. In contrast, the DHA-supplemented diet inhibited the development of proteinuria and suppressed hypertension. The mRNA levels for renal TGF-beta, fibronectin and renin were higher in the rapeseed oil and safflower oil groups after 9 weeks of feeding of the experimental diet than in the soybean oil and DHA groups. The fatty acid composition of kidney phospholipids was markedly affected by these diets. These results indicate that the renal injury observed in the groups fed safflower oil with a high n-6/n-3 ratio and rapeseed oil with presumed minor components is accompanied by increased expression of the TGF-beta, renin and fibronectin genes, and that dietary DHA suppresses renal injury and gene expression as compared with soybean oil.

Animals↗
PubMed2000

Meconium peritonitis in utero.

To clarify the relationship between clinical features in utero and postnatal prognosis, 20 fetuses who underwent ultrasonic (US) evaluation for meconium peritonitis (MP) over a 17-year period were reviewed. According to final US findings in utero, patients were classified into three types. Type I (massive meconium ascites) was noted is 5 cases, type II (giant pseudocyst) in 4, and the other 11 were classified as type III (calcification and/or small pseudocyst). Abdominal calcifications were identified in only 5 cases (2 type I, 1 type II, 2 type III). Seven fetuses who had associated polyhydramnios (1 Type I, 1 Type II, 2 Type III) and fetal hydrops (3 Type II) were delivered before 36 weeks' gestation. Cardiopulmonary resuscitation at birth was required in 9 cases (5 type I, 4 type II) who underwent abdominal drainage before delivery and/or immediately after birth. Although dilatation of the intestine was identified in 10 fetuses (2 type II, 8 Type III), 18 had intestinal atresia and 2 had fecal obstruction of the distal ileum. Four infants (2 type I, 1 type II, 1 type III) died of respiratory failure and postoperative complications. These results indicated that careful fetal US may be useful for perinatal management of MP.

Ascites↗