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Y Sakurai

Publications and source records attributed to Y Sakurai.

At least 127 records · Page 7Linked to original sources
PubMed1999

Vitellogenin-6 is a major carbonylated protein in aged nematode, Caenorhabditis elegans.

Recently we found that protein carbonyl content increases with age in wild-type as well as long- and short-lived Caenorhabditis elegans nematodes in inverse correlation with life span (Adachi et al., J. Gerontol. 53A, B240-B244, 1998; Yasuda et al., J. Gerontol. 54A, B47-B51, 1999). In the present study, we investigated carbonyl modification of individual proteins in young and old wild-type nematodes by two-dimensional immunoblot using antibodies against 2, 4-dinitrophenylhydrazones. A protein with apparent molecular weight of 110 kDa was found to be a major carbonylated protein in aged animals. Amino acid sequence of peptide fragments of the protein was identical to that of vitellogenin-6, a yolk protein synthesized in and secreted from the intestine during egg-laying stage. Although the function(s) of the protein in aged nematodes is unclear, we suggest that the protein may have a role to protect other cellular components from oxidation because of its metal binding capacity.

Age Factors↗
PubMed1999

Localization of peptidylarginine deiminase type II in a stage-specific immature oligodendrocyte from rat cerebral hemisphere.

Myelin basic protein (MBP) is composed of multiple charged isomers as the products of various posttranslational modifications. The least cationic component contains six citrulline residues converted from arginine residues by peptidylarginine deiminase (PAD). The modified MBP differs markedly from unmodified MBP in the ability to aggregate acidic lipid vesicles. However, the localization of PAD in brain has remained rather elusive. We performed Western blotting and immunocytochemical analyses of PAD type II and found that it was present in stage-specific immature oligodendrocytes but not in either type-1 astrocytes or neurons. We also confirmed that only the oligodendrocyte homogenate contained the PAD activity utilizing a sensitive method to detect citrulline-containing proteins. These data suggest that PAD type II localized in oligodendrocytes is responsible for deiminating MBP.

Animals↗
PubMed1999

Two-Layer Structure of Microcapsule Membrane as Predicted from Electrophoretic Studies.

Four types of hydrophilic gel microcapsules containing water have been prepared by an interfacial polymerization method. Each type of microcapsules has membranes of different compositions. Using three kinds of monomers, N,N-dimethylacrylamide (DMAAm), 4-aminomethylstyrene (AmSt), and N,N-dimethylaminopropylacrylamide (DMAPAA), two types of water-soluble copolymers with different compositions having primary and tertiary amino groups were obtained. Two more types of copolymers were synthesized by copolymerization of alpha-acryloxy-omega-methoxy-poly(ethylene glycol) (a-PEG) with the above two kinds of monomer mixtures. These copolymers were polymerized with terephthaloyldichloride at the water/oil interface to prepare four types of microcapsules containing water. By electrophoretic mobility measurements of these microcapsules and the analyses of the data, it was found that the surface layer of the microcapsule membranes were composed of two sublayers, each of which has different charge density and softness. The outer sublayer was negatively charged and inner sublayer was positively charged. By PEGylation, the charge density in the outer sublayer decreased, while that in the inner sublayer was not affected. Also, the surface layer became softer by PEGylation. The effects of membrane composition upon the swellability of the microcapsule membrane were studied. It was found that the asymmetrical structure of the microcapsule membranes causes the nonuniform distribution of charges and then the swellability of the microcapsule membrane changes depending on the permittivity of the dispersing medium. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

The cDNA cloning of human placental ecto-ATP diphosphohydrolases I and II.

The cDNA clones of two isoforms (enzymes I and II) of human placental ecto-ATP diphosphohydrolases have been isolated based on the N-terminal amino acid (aa) sequence of the immunopurified 82 kDa protein and characterized. The cDNA clone encoding enzyme I consists of 2081 nucleotides and the predicted enzyme I consists of 517 aa residues. Enzyme I has a 5'-UTR and an N-terminal 11 aa sequence that differ from CD39, but the rest of the sequence is the same as CD39. The hydropathy plot indicated that enzyme I has two hydrophobic regions near the N- and C-termini of the molecule. In contrast, enzyme II consists of 1814 nucleotides and the predicted protein consists of 306 aa residues. The sequence of 1-1018 nucleotides of enzyme II is identical to that of enzyme I, but the 1019-1814 nucleotide sequence is different from both enzyme I and CD39. The hydropathy plot indicated that enzyme II has one hydrophobic region near the N-terminus, suggesting that enzyme II is also anchored to the cell membrane. It is, however, likely that some of enzyme II exists as a soluble form in plasma, possibly after proteolytic processing.

Adenosine Triphosphatases↗
PubMed1999

Decrease in culture temperature releases monolayer endothelial cell sheets together with deposited fibronectin matrix from temperature-responsive culture surfaces.

Bovine aortic endothelial cells were cultured on surfaces grafted with a temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm), in the presence of serum. Cells adhered, spread, proliferated, and reached confluency as observed on ungrafted tissue culture polystyrene dishes. A decrease in culture temperature released cells only from the grafted surfaces without enzymatic or ethylenediaminetetraacetic acid treatment. Upon lowering temperature, the culture surfaces changed from hydrophobic to hydrophilic owing to the hydration of grafted PIPAAm and thus weakened the cell attachment to the dishes. Released cells maintained cell-cell junctions composing monolayer cell sheets. Immunoblotting and immunofluorescence microscopy revealed that fibronectin (FN) was deposited and accumulated on the grafted surfaces during the culture. Furthermore, the deposited FN matrix adhering to cell sheets was also recovered from temperature-responsive surfaces by low-temperature treatment, while trypsin treatment destroyed the matrix. The recovery of FN by low-temperature treatment was as high as by physical scraping with a rubber blade. Temperature-responsive surfaces can provide a novel method to use cultured confluent cell sheets for tissue engineering, and also to elucidate structure and function of deposited extracellular matrix during cell culture.

Acrylamides↗
PubMed1999

Reoxygenation in quiescent and total intratumor cells following thermal neutron irradiation with or without (10)B-compound-compared with that after gamma-ray irradiation.

PURPOSE: Reoxygenation in quiescent (Q) and total tumor cells within solid tumors after thermal neutron irradiation with or without (10)B-compound was examined, comparing with that following gamma-ray irradiation. METHODS AND MATERIALS: C3H/He mice bearing SCC VII tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty minutes after intraperitoneal injection of sodium borocaptate-(10)B (BSH), or 3 h after oral administration of dl-p-boronophenylalanine-(10)B (BPA), the tumors were irradiated with thermal neutrons, or those without (10)B-compounds were irradiated with thermal neutrons alone or gamma-rays. At various time points after each treatment, a series of test doses of gamma-rays were given to tumor-bearing mice while alive or after being killed to obtain hypoxic fractions in the tumors. Immediately after irradiation, the tumors were excised, minced, and trypsinized. Following incubation of tumor cells with cytokinesis blocker, the micronucleus (MN) frequency in cells without BrdU labeling ( = Q cells) was determined using immunofluorescence staining for BrdU. The MN frequency in the total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU. The MN frequency of BrdU-unlabeled cells was then used to calculate the surviving fraction of the unlabeled cells from the regression line for the relationship between the MN frequency and the surviving fraction of total tumor cells. RESULTS: In both total and Q tumor cells, the hypoxic fractions immediately after each treatment went up suddenly. Reoxygenation after each treatment occurred more rapidly in total cells than in Q cells. In both cell populations, reoxygenation appeared to be rapidly induced in the following order: neutron irradiation without (10) gamma-ray irradiation. CONCLUSION: Based on our previous report that total and Q cell fractions within these tumors have larger acutely and chronically hypoxic fractions, respectively, acute hypoxic cells appeared to play a larger role in reoxygenation. BSH was thought to have a potential to distribute more homogeneously in solid tumors than BPA, because BSH induced the nearer reoxygenation pattern to that following neutron irradiation alone than BPA.

Animals↗
PubMed1999

Establishment of a human hemangiosarcoma cell line (ISO-HAS).

A cell line (ISO-HAS) has been established from tumor tissue of a human hemangiosarcoma arising on the scalp by the use of conditioned medium from a murine-phenotypic angiosarcoma cell line (ISOS-1). Cells have been cultured for more than 2 years with up to 100 passages. The cells retained endothelial-cell properties, such as a characteristic cobblestone appearance at confluency, contact-inhibited growth, active uptake of acetylated low-density lipoprotein labeled with 1,1-dioctadecyl 1,3,3,3,3-tetramethyl-indocarbocyanine perchlorate (DiI-Ac-LDL) and CD31 expression. However, they were weakly positive for von-Willebrand-factor (vWf) antigen and for binding of Ulex europaeus agglutinin-I (UEA-I) lectin, and lacked tube-formation activity. These findings indicate that ISO-HAS is a poorly differentiated endothelial cell line. ISO-HAS cells showed accumulation of p53 protein in the nuclei, and a new-typed p53-gene point mutation was found in exon 7 at codon 240. When inoculated s.c. into severe-combined-immunodeficiency (SCID) mice, the cells showed solid-tumor growth that caused death. These properties suggest that ISO-HAS is a malignant endothelial cell line with high tumorigenicity.

Animals↗
PubMed1999

Carbonylated proteins in aging and exercise: immunoblot approaches.

Protein carbonyls were studied in aging and exercise by immunoblot followed by one- or two-dimensional polyacrylamide gel electrophoresis using antibodies against 2,4-dinitrophenylhydrazones. Proteins of rat kidneys exhibited significant age-related increase in the amount of carbonyl while those of the brain and liver did not. Major carbonylated proteins in the kidney included serum albumin. In nematodes in which protein carbonyls increased with age, one of the carbonylated proteins was identified as vitellogenin, an egg-yolk protein. A possible biological significance of this protein present in abundance even after egg-laying stages is discussed in terms of protection against oxidative stress. Exhaustive exercise induced significant increase in the carbonylation of selected but unidentified proteins in the lung. This oxidative stress might be caused by xanthine oxidase in this tissue and hypoxanthine derived from ATP-depleted muscles. Exercise at high altitude caused higher carbonylation of the skeletal muscle proteins, most notably a protein likely to be actin, than that at sea level but no significant difference was observed in lipid peroxidation. These studies emphasize the value of immunoblot analysis of tissue protein carbonyls in a variety of situations where oxidative stress is likely involved.

Aging↗
PubMed1999

Effect of Ca2+-alginate gel dissolution on release of dextran with different molecular weights.

Release of macromolecular drug from calcium-alginate gel beads was investigated. Fluorescein isothiocyanate-labeled dextrans with molecular weight ranging from 9400 to 145000 were used as a model macromolecular drug. Dextran release was observed to be molecular weight-dependent, with the release pattern changing from pseudo first-order for dextran with 9400 molecular weight to sigmoidal for dextran with molecular weight of 145000. Release of a lower molecular weight dextran is mainly governed by the drug diffusion through the calcium-alginate gel matrix. With increasing dextran molecular weights, dextran release was strongly influenced by the dissolution of alginate matrix through the exchange of Ca2+ ions which act as a cross-linker. Rapid and complete release was achieved for dextran with 145000 molecular weight in a "burst" fashion showing a initial lag time. Minimal dextran release was observed in pseudo-gastric fluid at pH 1.2, while rapid dextran release within a narrow time range was achieved in simulated intestinal fluid at pH 6. 8. These results strongly suggest that calcium-alginate gel is a useful vehicle for pulsatile release of macromolecular drugs in oral drug delivery.

Alginates↗
PubMed1999

Association between duration of obesity and risk of non-insulin-dependent diabetes mellitus. The Sotetsu Study.

The authors investigated the association between duration of obesity (ordinary obesity as body mass index (BMI) (kg/m2) > or = 25.0 and extreme obesity as BMI > or = 27.8) and the risk of diabetes mellitus. Male employees of a railway company, aged 30 years or older, observed for 10 years or more, free from serious disease conditions, with initial BMI <25.0, aged 30 years or more at the time diabetes was diagnosed, and with complete data, were examined by univariate and multivariate analyses (n = 1,598). Age-adjusted odds ratios for diabetes were significantly increased among males who were obese for 10-19.9 years and >20 years (odds ratios = 2.10 and 2.84 for ordinary obesity and 6.14 and 4.15 for extreme obesity, respectively). Additional adjustment for current obesity, physical activity, smoking, drinking, family history, and observation period did not change the findings remarkably. In conclusion, > or = 10 years duration of ordinary obesity or > or = 1 year of extreme obesity was an important predictor for diabetes independent of age, current obesity, physical activity, smoking, drinking, family history, and observation period.

Adult↗
PubMed1999

Signal transduction and cytoskeletal reorganization are required for cell detachment from cell culture surfaces grafted with a temperature-responsive polymer.

We have developed a new cell culture substrate grafted with a temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm) using an electron beam irradiation method. These surfaces are hydrophobic in culture at 37 degrees C due to the hydration/dehydration changes intrinsic to PIPAAm at 32 degrees C, and they become highly hydrophilic below 32 degrees C. At 37 degrees C grafted and ungrafted surfaces showed no difference with regard to attachment, spreading, growth, confluent cell density, and morphology of bovine aortic endothelial cells. Stress fibers, peripheral bands, and focal contacts were established in similar ways. After the medium temperature was decreased to 20 degrees C, spread cells lost their flattened morphology, acquiring a rounded cell appearance similar to that of cells immediately after plating. After mild agitation cells floated free from the dish surface without trypsin treatment. Neither cell morphological changes nor cell detachment occurred on ungrafted surfaces. An ATP synthesis inhibitor, sodium azide, and a tyrosine kinase inhibitor, genistein, suppressed cell morphological changes and cell detachment while a protein synthesis inhibitor, cycloheximide, slightly enhanced cell detachment. An actin filament stabilizer, phalloidin, and its depolymerizer, cytochalasin D, also inhibited cell detachment. These findings suggest that cell detachment on grafted surfaces is mediated by intracellular signal transduction and reorganization of the cytoskeleton. While trypsinization causes damage to the cell membrane surface and extracellular matrix proteins, this alternative low temperature treatment is exceptionally noninvasive. The temperature-responsive cell culture surface also should prove useful for investigating the molecular machinery involved in cell-surface detachment.

Acrylic Resins↗
PubMed1999

Repair of potentially lethal damage by total and quiescent cells in solid tumors following a neutron capture reaction.

PURPOSE: We analyzed the time-course of changes in the sensitivity of total (proliferating + quiescent and quiescent (Q) cell populations within solid tumors in situ following a neutron capture reaction and compared it with that after gamma-ray irradiation. METHODS: After continuous labeling of proliferating cells with BrdU for 5 days, mice bearing SCC VII tumors received thermal neutron irradiation with or without a (10)B-labeled compound (sodium [(10)B]borocaptate, BSH, or DL-p-[(10)B]boronophenylalanine, BPA), or gamma-ray irradiation. From 5 min to 72 h after treatment, tumors were excised, minced, and trypsinized. Cell suspensions were incubated for 48 h with the cytokinesis blocker cytochalasin-B. The micronucleus frequency for BrdU-unlabeled cells, Q cells at treatment, was then determined by immunofluorescence staining for BrdU. The micronucleus frequency for total cells was obtained from tumors that had not been pretreated with BrdU labeling. The sensitivity was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (micronucleus frequency). RESULTS: Overall, Q cells showed greater repair capacities than total cells. gamma-Ray irradiation and neutron irradiation with BPA induced larger repair capacities in each cell population. In contrast, thermal neutron irradiation without a (10)B-labeled compound induced the smallest repair capacity in both cell populations. The use of a (10)B-labeled compound, especially BPA, widened the difference in sensitivity between total and Q cells, resulted in an increase in repair capacity in both cell populations, and made the repair patterns of the two cell populations look like those induced by gamma-ray irradiation. CONCLUSION: Differences in sensitivity and repair patterns following the neutron capture reaction were thought to depend on differences in the distribution of the (10)B-labeled compound between the proliferating and Q cell populations.

Animals↗
PubMed1999

p53 gene mutations and overexpression of p53 product in cancerous and noncancerous biliary epithelium in patients with pancreaticobiliary maljunction.

To investigate the molecular mechanisms of the high incidence of carcinogenesis in the biliary epithelium of patients with pancreaticobiliary maljunction, we examined p53 gene mutations, loss of heterozygosity of p53, and overexpression of p53 gene product in the cancerous and noncancerous biliary epithelium of 27 patients with pancreaticobiliary maljunction. Mutations of the p53 gene were examined by polymerase chain reaction-single strand conformation polymorphism and a direct sequencing method. Loss of heterozygosity of the p53 gene was determined using a double-targeted fluorescence in situ hybridization method. Expression of p53 gene product was examined using immunohistochemical staining. Mutations of the p53 gene were found in 4 of 5 biliary carcinomas (80%) and in 10 of 26 noncancerous biliary lesions (38.5%). Point mutations of the p53 gene were detected at codons 207, 212, and 217 on exons 5 through 8. The incidence of p53 gene mutations on exons 5, 6, 7, and 8 was 12. 9%, 36.4%, 0.0%, and 13.8%, respectively. Loss of heterozygosity of p53 was shown in 72% of the cells obtained from the cancerous lesion, and in an average of 14% obtained from the noncancerous lesions. Overexpression of p53 protein was found in 57.1% of carcinoma, and in 31.3% of the noncancerous lesions. These results suggest that p53 gene mutations are involved in the carcinogenesis of biliary epithelium in patients with pancreaticobiliary maljunction.

Adult↗
PubMed1999

Pulmonary barotrauma in congenital diaphragmatic hernia: a clinicopathological correlation.

BACKGROUND/PURPOSE: The high mortality rate in congenital diaphragmatic hernia (CDH) has been ascribed to pulmonary hypoplasia and persistent pulmonary hypertension of the newborn (PPHN). One of the principal treatment strategies has been the use of hyperventilation to reverse ductal shunting, but the wisdom of this approach is being questioned because of parenchymal lung injury from high inflation pressures. The authors hypothesize that the use of hyperventilation to reverse or prevent ductal shunting would result in ventilator-induced lung injury, which would be evident on postmortem examination. A retrospective review of clinical and autopsy information was conducted. METHODS: Clinical and autopsy information gathered for a previously published series of 223 infants with CDH presenting in the first 24 hours of life was reviewed. Autopsy and clinical data were analyzed from 68 of 101 nonsurvivors who died with severe hypoxemia. RESULTS: Sixty-two of 68 cases (91%) had evidence of diffuse alveolar damage and hyaline membrane formation, which was more evident in the ipsilateral lung. Forty-four (65%) infants had pneumothoraces, and 4 infants had interstitial fibrosis. Pulmonary hemorrhage was seen in 35 cases (50 maximum peak inspiratory pressure [mean +/- SD] was 40.4+/-7.9 cm H2O and lowest modified ventilatory index [respiratory rate x peak airway pressure] was 2323+/-836). The degree of pulmonary hypoplasia was evaluated by lung weight with the ratio of the observed combined lung weight to the expected lung weight based on birth weight and gestational age. The ratio based on birth weight was 57%+/-25%, and the ratio based on gestational age was 60%+/-26%. Twenty-one infants (35%) had nonpulmonary anomalies. The most significant was a 10% incidence of congenital heart disease. Apart from this, lethal nonpulmonary anomalies were rare. CONCLUSION: These results suggest that lung injury secondary to mechanical ventilation plays an important role in the mortality rate of patients with CDH, which may become increasingly significant when there is underlying pulmonary hypoplasia.

Barotrauma↗
PubMed1999

How do cell assemblies encode information in the brain?

The present review discusses why cell-assembly coding, i.e. ensemble coding by functionally connected neurons, is a tenable view of the brain's neuronal code and how it operates in the working brain. The cell-assembly coding has two major properties, i.e., partial overlapping of neurons among assemblies and connection dynamics within and among the assemblies. The former is the ability of one neuron to participate in different types of information processing. The latter is the capability for functional synaptic connections, detected by activity correlations of the neurons, to change among different types of information processing. An example of a series of experiments which detected these two major properties is then given. Several relevant points concerning the detection of the actual dynamics of cell-assembly coding are also enumerated. They include the dependence of the type of cell-assembly coding on types of information-processing in different structures of the brain, sparse coding by distributed overlapped assemblies, and coincidence detection as a role of individual neurons to bind distributed neurons into cell assemblies.

Animals↗
PubMed1999

Coffee drinking and serum gamma-glutamyltransferase: an extended study of Self-Defense Officials of Japan.

PURPOSE: To examine the effect of coffee drinking on serum gamma-glutamyltransferase (GGT) level in relation to alcohol drinking, smoking, and degree of obesity in middle-aged Japanese men. METHODS: From 1986 to 1994, a total of 7,637 male officials of the Self-Defense Forces of Japan aged 48-59 years received a preretirement health examination. Coffee drinking was ascertained by a self-administered questionnaire, and serum GGT level was measured. After excluding 1,360 men with a possible pathologic condition influencing liver enzyme levels and 182 former alcohol drinkers, effect of coffee drinking on serum GGT was examined by a multiple linear regression model and analysis of variance adjusting for alcohol drinking, smoking, and body mass index (BMI). RESULTS: The adjusted percentage of difference in serum GGT was -4.3 (95% CI = -5.0; -3.5) per cup of coffee. The inverse coffee-GGT relation was most prominent among men drinking > or = 30 ml of ethanol and smoking > or = 15 cigarettes daily; and positive associations of alcohol and smoking with GGT were attenuated by coffee drinking, more clearly among men with BMI > or = 25.00 kg/m2. Adjusted percentages of difference in serum GGT were -2.6% (p = 0.0003) per cup of brewed coffee, and -5.1% (p = 0.0001) per cup of instant coffee, independently of each other. CONCLUSIONS: The present study suggests that coffee consumption may weaken GGT-induction by alcohol, and possibly by smoking. These effect modifications by coffee may differ according to the degree of obesity.

Alcohol Drinking↗
PubMed1999

Impaired glucose tolerance, diabetes mellitus, and gallstone disease: an extended study of male self-defense officials in Japan.

Few studies have investigated the relation between glucose tolerance status and ultrasonographically determined gallstone disease. Using a 75-g oral glucose tolerance test, we examined the association of impaired glucose tolerance (IGT) and non-insulin-dependent diabetes mellitus (NIDDM) with gallstone disease in Japanese men. Subjects were men aged 48 to 59 of the Japan Self-Defense Forces who received a preretirement health examination between October 1986 to December 1994. After exclusion of 12 men under insulin treatment in the consecutive series of 7637 men, 174 were found to have gallstones; 103 were at the state of postcholecystectomy, and 6899 had normal gallbladder. IGT and NIDDM were associated with a modestly increased risk of gallstone disease; adjusted odds ratios were 1.3 (95% confidence interval [CI]: 0.9-1.8) for IGT and 1.3 (95% CI: 0.8-2.0) for NIDDM after adjustment for hospital, rank, smoking, alcohol use, and body mass index. Adjusted odds ratio for IGT and NIDDM combined was 1.3 (95% CI: 1.0-1.7, p=0.08). When prevalent gallstones and postcholecystectomy were considered separately, NIDDM showed a significant, positive association with postcholecystectomy, but not with prevalent gallstones. The findings add to evidence that glucose intolerance is associated with a modest increase in the risk of gallstone disease.

Cholecystectomy↗