Search PubMed⌕ Search

Biomedical subjects

S Oikawa

Publications and source records attributed to S Oikawa.

At least 109 records · Page 6Linked to original sources
PubMed1998

Aneurysm surgery in Asia--Japanese situation.

This report is based on the results of the questionnaires conducted for the Japan Stroke Surgery Meeting 1996 (President: S. Kobayashi). The questionnaires were sent to all neurosurgical training institutions approved by The Japan Neurosurgical Society, numbering 959. The response rate was 54.2% (520 institutions). All statistics dealt with cases from January 1995 to December 1995. The total number of aneurysm surgery performed was 13,166. The average operative case number per institution during the year was 25. About 20% of the institutions exceeded 35 cases. Of all operative cases, 76.3% were ruptured aneurysms and 23.7% were nonruptured. Giant aneurysms were 2.9%; dissecting aneurysms 2.4%. Surgical procedures performed were clipping in 90.3%, wrapping in 5.2%, proximal ligation 1.6%, and bypass in 0.7%. Intravascular surgery was performed for 2.3% of the cases. Sugita clips were mainly used in 80.5% of the institutions, Yasargil clips in 6.6%, and both in 12.9%. For anterior communicating artery aneurysms pterional approach was mainly used in 81.0% of the institutions, interhemispheric in 7.2%, and both in 11.7%. For basilar terminal aneurysms, pterional approach was mainly used in 88.3% of the institutions, subtemporal approach in 6.6%, and both in 5.1%. The nonoperative cases included 24.9% of the ruptured aneurysms, 31.7% of the unruptured aneurysms, 38.4% of the giant aneurysms, and 52.1% of the dissecting aneurysms. The above statistics suggest that aneurysms are treated in Japan in most training institutions and that open surgical treatment is still the main procedure of choice.

Humans↗
PubMed1998

Surgical anatomy of the juxta-dural ring area.

OBJECT: The authors report on the surgical anatomy of the juxta-dural ring area of the internal carotid artery to add to the information available about this important structure. METHODS: Twenty sides of cadaver specimens were used in this study. The plane of the dural ring was found to incline in the posteromedial direction. Medial inclination was measured at 21.8 degrees on average against the horizontal line in the anteroposterior view on radiographic studies. Posterior inclination was measured at 20.3 degrees against the planum sphenoidale in the lateral projection, and the medial edge of the dural ring was located 0.4 mm above the tuberculum sellae in the same projection. The lateral edge of the dural ring was located 1.4 mm below the superior border of the anterior clinoid process. The carotid cave was situated at the medial or posteromedial aspect of the dural ring; however, two of the 20 specimens showed no cave formation. The carotid cave contained the subarachnoid space in 13 sides, the arachnoid membrane only in three sides, and the extraarachnoid space in two sides. The authors propose that the marker of the medial side of the dural ring, which is more proximal than the lateral, is the tuberculum sellae in the lateral view on radiographic studies. In the medial aspect of the dural ring the intradural space can be situated below the level of the tuberculum sellae because of the existence of the carotid cave. CONCLUSIONS: An aneurysm arising from the medial side of the juxta-dural ring area even below the tuberculum sellae is a potential cause of subarachnoid hemorrhage.

Aneurysm↗
PubMed1998

Identification and purification of apolipoprotein C-III from the serum of cows.

OBJECTIVE: To identify, purify, and analyze distribution of apolipoprotein C-III in lipoprotein fractions and to evaluate its concentration in serum from calves, heifers, and cows during various stages of lactation. SAMPLE POPULATION: Sera from 3 female calves, 3 heifers, and 12 cows during early, middle, late, and nonlactation stages. PROCEDURE: Apolipoprotein C-III was identified by use of amino-terminal amino acid sequence analysis of bands separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purification was performed by extraction with acetone, delipidation with 2-propanol, and 2 chromatographic steps. The apolipoprotein C-III concentration in the total lipoprotein fraction was evaluated by densitometric scanning of the bands for apolipoprotein C-III separated by electrophoresis, using purified apolipoprotein C-III as an internal standard. RESULTS: Apolipoprotein C-III was identified as 8.2- and 7.3-kd proteins with identical amino acid sequences. The 2 proteins were mainly found in the high-density lipoprotein fraction, then were purified separately. Serum apolipoprotein C-III concentration was significantly (P < 0.05) higher in cows during lactation than in nonlactating cows and was negatively correlated with serum triglyceride concentration (r = -0.620, P < 0.01). CONCLUSIONS: The role of apolipoprotein C-III in cows may involve a function related to lactation.

Aging↗
PubMed1998

Evaluation of serum apolipoprotein C-III concentration by enzyme-linked immunosorbent assay and its higher concentration in cows during midlactation than during the nonlactating stage.

OBJECTIVE: To determine serum apolipoprotein C-III (apoC-III) concentration in cows in various stages of lactation by use of an ELISA. SAMPLE POPULATION: Sera obtained from 29 Holstein cows during early lactation, 65 cows during midlactation, 42 cows during late lactation, and 23 cows during the nonlactating stage. PROCEDURE: A 7.3-kd bovine apoC-III antiserum raised in rabbits was purified by affinity chromatography, and an ELISA was developed. RESULTS: In the immunoblot analysis, the antiserum reacted with the 7.3-kd apoC-III and moreover with another 8.2-kd apoC-III isoform. The 2 isoforms of apoC-III were also indistinguishable in the developed ELISA, the 2 proteins being measured as total apoC-III. In the ELISA for serum apoC-III concentration, addition of 2-mercaptoethanol to the coating buffer (50 mM sodium carbonate buffer, pH 9.6) was required. Mean+/-SEM bovine serum apoC-III concentration (microg/ml of serum) was 71.6+/-12.1 for the early lactating stage, 115+/-14.0 for the midlactating stage, 104+/-18.8 for the late lactating stage, and 55.3+/-8.4 for the nonlactating stage. Concentration of apoC-III was significantly (P < 0.05) higher in cows during midlactation than in cows during the nonlactating stage and was correlated negatively with serum triglyceride concentration (r = -0.479; P < 0.01) and positively with total cholesterol (r = 0.421; P< 0.05) and phospholipids (r= 0.415; P< 0.05) concentrations. CONCLUSIONS: Changes of apoC-III concentration in various stages of lactation suggest that this apolipoprotein is involved in a function related to lactation.

Animals↗
PubMed1997

Decreased sensitivity of carcinoembryonic antigen cDNA-transfected cells to adriamycin.

Carcinoembryonic antigen (CEA) is a heavily glycosylated protein and is expressed at a high frequency in adenocarcinomas, which are known to be one of the cancers most resistant to chemotherapeutic agents. In this study, with the aim to elucidate whether CEA participates in drug resistance or not, we tested the adriamycin (ADR) sensitivity of CEA transfectants of H-ras-transformed NIH 3T3 cells in vitro and in vivo. The ADR sensitivity of CEA transfectants in vitro was evaluated as growth (% of control) when incubated with various concentrations of ADR, and showed that they were higher than those of mock transfectants. The decreased ADR sensitivity of CEA transfectants in vivo was also observed as an increase in tumor size after intraperitoneal administration of ADR into SCID mice. To define the mechanisms for resistance, the accumulation and efflux of ADR in transfectants was examined. The rate of ADR accumulation in CEA transfectants was reduced compared to mock transfectants, caused at least partly by an increased efflux out of the cells. Furthermore, the modification of N-glycan on CEA by deoxymannojirimycin, an N-glycosylation processing inhibitor, partially restored ADR sensitivity of CEA transfectants, suggesting an involvement of sugar chains. Our data suggest that CEA expression may decrease ADR sensitivity of cancer cells.

Animals↗
PubMed1997

Expression of human inducible nitric oxide synthase is regulated by both promoter and 3'-regions.

One of the mechanisms underlying the induction of human inducible nitric oxide synthase (hiNOS) by cytokines is transcriptional regulation. However, previous reports suggest that in human cells, the cytokine activation of the hiNOS expression is accompanied by a drastic increase in cellular mRNA and protein content, but by little increment in transcriptional activity. We designed luciferase reporter constructs containing the hiNOS 5'-flanking region and 3'-untranslated region (UTR). The construct containing both 5'-flanking region and 3'-UTR plus its downstream canceled the constitutive activity of the reporter gene, and was more responsive to the cytokines. This is an initial attempt to highlight the important role played by the 3'-region of the hiNOS gene. Our studies provide the evidence that the cooperative interaction between the 5'-promoter and the 3'-region conveys marked induction of the gene in the presence of cytokines.

Base Sequence↗
PubMed1997

Effects of amino acid replacements on cadmium binding of metallothionein alpha-fragment.

To evaluate whether only 20 cysteine residues at invariant positions are needed to bind and coordinate the metals in metallothioneins (MTs), and whether changing the positions of cysteine residues in the sequence affects the metal-binding capacity and the coordination of MTs, we examined the cadmium-binding affinities of seven mutant MT alpha s using an Escherichia coli expression system. Five mutant MT alpha s in which the constitutive amino acid residues other than cysteines of the alpha-fragment were replaced with glycine residues, and the remaining two mutant MT alpha s in which the invariant positions of the cysteine residues of the alpha-fragment were shifted, were analysed for their ability to be expressed as cadmium-binding forms and for their biochemical properties. The results showed that extreme alteration of the constitutive amino acid residues other than cysteines in the MT alpha-fragment leads to disruption of their cadmium-binding abilities and of their structure. However, mutant MT alpha s containing changes of the invariant positions of the cysteine residues were expressed in a cadmium-binding form in Escherichia coli, although the invariant positions of 20 cysteine residues in the MTs are thought to be important for their metal-binding abilities. These results suggest that the position of cysteine residues and the chemical nature of the other amino acids in the amino acid sequence of MTs are less critical than expected.

Amino Acid Sequence↗
PubMed1997

Decreased serum lecithin:cholesterol acyltransferase activity in spontaneous cases of fatty liver in cows.

Lecithin:cholesterol acyltransferase (LCAT) activity in serum was evaluated in spontaneous cases of fatty liver in cows. The enzyme activity of 631 +/- 62 U (mean +/- SEM, decrease in nmol of free cholesterol per h per ml of serum) in cows with fatty liver (n = 16) was significantly (p < 0.01) lower than that in cows without fatty liver (979 +/- 22 U; n = 16). In addition to the decrease in LCAT activity, the concentrations of phosphatidylcholine (a fatty aryl donor for esterification of free cholesterol) and of cholesteryl esters (products of the LCAT reaction) were reduced in the high-density lipoprotein fractions from cows with fatty livers. The concentrations in the serum of apolipoprotein A-I, an activator of LCAT, was also reduced in cows with fatty livers. These results suggest that the decreased LCAT activity, which may be attributable to impaired hepatic secretion or to the suppression of the activity in the plasma by reduced concentrations of phosphatidylcholine and apolipoprotein A-I, resulted in the lower concentrations of cholesteryl esters. Because cholesteryl esters are utilized in steroidogenic tissues for the synthesis of steroid hormones such as progesterone and glucocorticoids, and insufficient supply of the cholesterols may be of relevance to the reduced fertility and immune competence observed in cows with fatty livers.

Animals↗
PubMed1997

Synthesis and messenger ribonucleic acid expression of apolipoproteins E and A-I by the bovine corpus luteum during the estrous cycle and pregnancy.

In an attempt to characterize proteins secreted by the corpus luteum, explant cultures of luteal slices from cows taken on Days 3, 7, 11, 14, 17, and 19 of the estrous cycle, and Days 17, 88, 180, and > 240 of pregnancy were incubated with H-leucine for 24 h. Proteins in luteal-conditioned medium were separated by two-dimensional PAGE, transferred to polyvinylidene fluoride membrane, and subjected to N-terminal amino acid microsequencing. Microsequence analysis revealed that the bovine corpus luteum synthesized and released de novo synthesized apolipoproteins (Apo) E and A-I in culture during the estrous cycle and pregnancy. Release of Apo E was observed only on Day 3 of the estrous cycle. Release of Apo A-I was observed on Days 11, 14, 17, and 19 of the estrous cycle, and on all days of pregnancy examined. To demonstrate the presence of the appropriate mRNA and characterize the temporal relationship for these identified proteins, total RNA was isolated from corpora lutea on Days 2, 3, 7, 16, 17, and 20 of the estrous cycle, and on Days 17, 90, 170, 180, and 272 of pregnancy, and submitted to Northern and dot blot analysis. Apo E mRNA was expressed only on Days 2-3 of the estrous cycle and was not expressed on the other days of the cycle or during pregnancy. A single Apo E mRNA transcript about 1.0 kilobase (kb) in size was observed. Expression of Apo A-I mRNA was detected on all days of the estrous cycle and pregnancy examined. Apo A-I cDNA hybridized with a single mRNA transcript about 1.0 kb in size. Apo A-I mRNA levels did not differ among days of the estrous cycle, although higher levels of Apo A-I mRNA were observed during later stages of pregnancy. Serum concentrations of Apo A-I and progesterone were correlated across the estrous cycle but not during the prepartum period or after parturition. This study demonstrates for the first time that the corpus luteum synthesizes Apo E and Apo A-I and expresses their respective mRNAs. The pattern of expression of Apo E and Apo A-I mRNAs paralleled that of de novo synthesis of their respective proteins after incubation of luteal tissue with [H]leucine. The role of luteal apolipoproteins may involve an autocrine/paracrine function influencing luteal development, tissue remodeling, and steroidogenesis.

Amino Acid Sequence↗
PubMed1997

Apolipoprotein E Sendai (arginine 145-->proline): a new variant associated with lipoprotein glomerulopathy.

Lipoprotein glomerulopathy (LPG) is a novel disease characterized by proteinuria, lipoprotein thrombi in the glomeruli, and increased concentration of plasma apolipoprotein (apo) E. It is believed that a genetic disorder of apo E may be present and associated with the disease. Three patients with LPG were examined in this study. The patients' DNA sequences were analyzed, and a nucleotide G to C point mutation in exon 4 of the apo E gene was confirmed in each patient. This missense mutation denotes amino acid substitution of the proline residue for arginine residue at position 145 of apo E. This variant (apo E Sendai) may cause a marked molecular conformational change of the apo E. These findings suggest that a novel variant is etiologically related to LPG.

Aged↗
PubMed1997

Decreased serum apolipoprotein B-100 and A-I concentrations in cows with ketosis and left displacement of the abomasum.

OBJECTIVE: To assess the relevance of hepatic lipidosis (fatty liver) in the development of ketosis and left displacement of the abomasum (LDA). SAMPLE POPULATION: Sera from 22 healthy cows in early lactation, 21 cows with ketosis, and 19 cows with LDA, and serum and liver specimens from 35 slaughtered cows with or without fatty liver, ketosis, and/or LDA. PROCEDURE: Apolipoprotein B-100 and A-I concentrations were measured in sera of healthy farm cows and of farm cows with ketosis and LDA. Serum apolipoprotein concentration, together with liver triglyceride content, also were surveyed in a subset of slaughtered cows. RESULTS: Compared with those in healthy cows or controls, apolipoprotein B-100 and A-I concentrations were decreased in cows with ketosis and LDA. CONCLUSIONS: Decreases in apolipoprotein B-100 and A-I concentrations in cows with ketosis and LDA indicate that the 2 disorders may be intimately associated with fatty liver. CLINICAL RELEVANCE: Monitoring of the apolipoprotein B-100 and A-I concentrations during the stages of nonlactation and early lactation is helpful for detecting cows susceptible to ketosis and LDA.

3-Hydroxybutyric Acid↗
PubMed1997

Immunohistochemical localization of alpha 1-acid glycoprotein in liver tissues of bovine fetuses, newborn calves, and sick or healthy adult cattle.

OBJECTIVE: To detect localization of alpha 1-acid glycoprotein (alpha 1-AG) antigens in the liver tissue of cattle by use of immunoperoxidase technique. SAMPLE POPULATION: Liver specimens from 6 bovine fetuses, 2 healthy bovine neonates, 2 healthy adult cattle, 3 cattle with experimentally induced hepatic abscesses, and 2 cattle with enzootic bovine leukosis (EBL). PROCEDURE: 3 cattle (with hepatic abscesses) were inoculated with a suspension of Fusobacterium necrophorum in the ruminal vein. Serum alpha 1-AG concentration was determined by use of the single radial immunodiffusion method. Livers from fetuses, newborn calves, and adult or sick cattle were fixed in buffered 10% formalin, dehydrated in alcohol, embedded in paraffin, sectioned, and stained by use of the avidinbiotin complex/immunoperoxidase technique. RESULTS: Sites of localization of the alpha 1-AG antigen positive reaction (AGPR) in the liver obtained from bovine fetuses, neonates, or sick cattle were different. In fetal and newborn calves, the AGPR was detected in the cytoplasm of hepatocytes. Intensity of the reaction varied in direct proportion to alpha 1-AG serum concentration. In adult cattle, the AGPR was particularly intense in hepatocytes adjacent to abscesses or EBL-induced tumors. CONCLUSIONS: The pattern of distribution of cells with AGPR in the liver varied, depending on severity of inflammation. In the cattle with EBL, whether the AGPR was attributable to inflammation could not be clarified, although suppression of immunologic response to tumors may have been a cause of the observed reaction. This association suggests that the glycoprotein may be synthesized, mainly in hepatocytes.

Animals↗
PubMed1997

Decreased serum apolipoprotein A-I concentrations in cows infected with Salmonella typhimurium.

Serum apolipoprotein A-I concentrations in cows infected with Salmonella Typhimurium were evaluated to assess its relevance in salmonellosis. Apolipoprotein A-I has been shown in rats to be secreted by the intestine as well as the liver. Clinical symptoms such as diarrhea revealed an outbreak of salmonellosis in 22 cows on a farm, and sera were obtained at 6 (acute phase), 16, 28 (convalescent period) and 42 d (postconvalescent period) after the outbreak. Apolipoprotein A-I concentrations (mean +/- SD, mg/mL), determined by ELISA, were 0.598 +/- 0.497 (day 6), 0.111 +/- 0.060 (day 16), 0.432 +/- 0.311 (day 28) and 0.727 +/- 0.516 (day 42). Compared with the concentration at day 42, those at 16 and 28 d were significantly (P < 0.01, P < 0.05) lower, but that at day 6 was not. The serum concentration of apolipoprotein B-100 (of liver origin in cattle) was unaltered during the course of salmonellosis. The concentration of apolipoprotein A-I was positively correlated with those of serum total cholesterol (r = 0.589, P < 0.01) and phospholipids (r = 0.590, P < 0.01). These results suggest that apolipoprotein A-I in cattle is in part of intestinal origin, and also that its decreased serum concentration in salmonellosis can be attributed to the reduced intestinal synthesis or secretion of this apolipoprotein. Moreover, as a potential carrier for dietary lipids such as cholesterol, determination of serum apolipoprotein A-I concentration is suggested to be useful when assessing the nutritional status of the affected cows.

Animals↗
PubMed1997

Reduced concentrations of apolipoproteins B-100 and A-I in serum from cows with retained placenta.

The purpose of the present study was to evaluate apolipoprotein B-100 and A-I concentrations in cows with retained placenta. Animals used were cows with retained placenta alone (n = 10), those with both retained placenta and ketosis (n = 7), and controls (n = 10). Apolipoprotein B-100 concentrations at 2 to 4 d after parturition were significantly (P < 0.01) decreased in cows with retained placenta alone (mean +/- SD, 0.084 +/- 0.029 mg/ML of serum) when compared with those in control cows (0.154 +/- 0.022 mg/mL). Apolipoprotein A-I concentrations (0.713 +/- 0.177 mg/ML) were also significantly (P < 0.05) lower than those of controls (0.895 +/- 0.159 mg/mL). These decreases were more distinct for apolipoproteins B-100 (55% of controls) than A-I concentrations (80% of controls). Concentrations of apolipoprotein B-100 (0.071 +/- 0.032 mg/mL; P < 0.01) and A-I (0.708 +/- 0.189 mg/mL; P < 0.05) in the cows with both retained placenta and ketosis were also reduced, when compared with values in controls. Other than apolipoproteins, cows with retained placenta alone had significantly (P < 0.01) higher serum nonesterified fatty acids, and lower triglyceride concentrations. Significantly (P < 0.01) higher nonesterified fatty acids and lower triglyceride concentrations were similarly observed in cows with both retained placenta and ketosis.

Analysis of Variance↗