Biomedical subjects

I Chinen

Publications and source records attributed to I Chinen.

At least 37 records · Page 2Linked to original sources

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↗

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

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↗

PubMed1994

Precursor role of branched-chain amino acids in the biosynthesis of iso and anteiso fatty acids in rat skin.

Monoester fraction of rat skin surface lipid has been shown to contain more than trace amounts of branched-long-chain fatty acids (BCFAs) of the iso and anteiso series. These BCFAs are biosynthesized using either branched-chain amino acids (BCAAs) or branched-chain alpha-keto acids (BCKAs), or using both of them as precursor. This study has been carried out to address which precursor, BCAAs or BCKAs in the circulation, are mainly utilized for biosynthesis of BCFAs. Dietary supplement of [14C]-valine and isoleucine-induced sharp rise of serum concentration of these two amino acids and their respective alpha-keto acids, and elevated the levels of related BCFAs and branched-chain fatty alcohols in the monoester fraction. A larger proportion of label in the total skin surface lipid was found in the monoester fraction in which fatty acid and alcohol accounted for approx. 80% of total radioactivity. Incorporation of intravenously administered [14C]-BCAAs and BCKAs into the monoester fraction revealed that BCAAs were far better as precursors than BCKAs for BCFA biosynthesis in rat skin. Among three BCAAs, leucine differed from valine or isoleucine in that this amino acid was primarily utilized for production of straight-chain fatty acids rather than for production of related BCFA.

Amino Acids, Branched-Chain↗

PubMed1994

Direct detection of Vibrio cholerae in stool samples.

A direct method to detect Vibrio cholerae in stool samples was developed by using a PCR procedure that did not require a DNA purification step. Dilution (1/100) of stool samples prevented inhibition of the reaction by contaminants, and two consecutive PCRs, the second one with a nested primer, achieved the desired sensitivity. Comparison of the results obtained from stool swab samples processed by the two-step PCR and by an enzyme-linked immunosorbent assay using GM1 as the capture molecule showed that the former is more sensitive and gave positive results even when V. cholerae was not culturable or dead.

Argentina↗

PubMed1994

Serum-free culture of rat keratinocytes.

Procedures for the serum-free culture of rat keratinocytes have been established. Basal cells prepared from epidermis of newborn rat were stored in liquid nitrogen and used for primary culture. Among the available media, MCDB 153, developed originally for human keratinocyte (HK) culture, was the best for the development of serum-free formulation. To grow rat keratinocytes, bovine serum albumin was arbitrarily substituted for the macromolecule supplements needed for HK culture, i.e. fetal bovine serum protein or bovine pituitary extract. Qualitative and quantitative adjustment of supplements was thereafter made to support rapid cell growth. Satisfactory cell growth was achieved in the optimized medium of MCDB 153 supplemented with growth factors and amino acids: insulin (10 micrograms/ml), hydrocortisone (0.1 microgram/ml), epidermal growth factor (25 ng/ml), calcium chloride (0.2 mM), histidine (0.23 mM), isoleucine (0.05 mM), tryptophane (0.015 mM), threonine (1.25 mM), tyrosine (0.031 mM), alanine (4.08 mM), and albumin (2 mg/ml). This optimized culture system was superior to the original HK culture condition for rapid growth of rat keratinocytes. Under our condition, cells grew as a monolayer, becoming confluent, but without stratification, and were passaged 2 to 3 times without any changes in morphology. The serum-free formulation allows us to control more accurately the concentrations of biomolecules in the medium including lipids and hormones, and therefore will be suitable for the study focusing on lipid metabolism or hormonal regulation of rat keratinocytes.

Amino Acids, Essential↗

PubMed1993

Lipoprotein and apoprotein profile of Japanese quail.

The present study delineated the lipoprotein and apoprotein distribution in Japanese quail. Quail lipoprotein was composed of three fractions: VLDL, d < 1.020; LDL, 1.020 < d < 1.081; HDL, 1.081 < d < 1.210. When animals were fed the cholesterol-free diet, HDL was the predominant form, LDL intermediate, VLDL and chylomicron were smallest in amount. Feeding of cholesterol induced a marked change in the lipoprotein profile: VLDL or chylomicron predominated over HDL and LDL. An apoprotein of 26 kD (molecular weight) was the major protein moiety comprising more than 50% of total apoprotein in the entire density range of lipoprotein class. Amino acid composition of 26 kD protein was similar to hen, rat and human apo A-I. N-Terminal 36 amino acid sequence of 26 kD protein showed 92% homology to chicken apo A-I and 11% homology to human apo A-1. The 26 kD protein did not react with the antibody raised against human apo A-I. These observation showed that the 26 kD protein was partially identical to apo A-I.

Amino Acid Sequence↗

PubMed1993

Fatty acid and lipid composition in vitro and in vivo of rat epidermis.

1. Fatty acid and lipid compositions of cultured rat keratinocytes were compared with those of intact epidermis prepared from newborn and adult rats. 2. The uniqueness of the lipid profile of cultured cell manifested itself in the accumulation of a novel lipid which co-migrated with monoalkyldiacylglyceride on thin-layer chromatography. 3. Concentration of the branched-chain fatty acid was specifically high in the cholesterol ester fraction of the intact cell, and was decreased by cultivation under submerged conditions.

Aging↗

PubMed1993

[Diagnosis of entero-invasive Escherichia coli associated with diarrhea].

Sixteen Escherichia coli strains isolated from diarrhea patients, characterized as enteroinvasive (EIEC) by the keratoconjunctivitis test (Sereny test), and 15 non-EIEC strains, were studied. The aim of this study was to establish a possible correlation between the Sereny test and several other tests as enzyme-linked immunosorbent assay (ELISA) and biochemical markers, which are more easily accessible to general practice laboratories. Strains were assayed for the virulence marker antigen (the outer membrane proteins) by direct ELISA, biochemical tests, antimicrobial susceptibility profile and serotyping. Mean optical density (OD) values in the ELISA were 2.018 +/- 0.336 for EIEC strains, and 0.569 +/- 0.283 for non-EIEC strains. Difference between the OD values of the two groups was found to be significant at p < 0.01 by the one-tailed Student's test. One (6.2%) of the 16 Sereny test-positive strains was negative by ELISA. Considered as a group, the EIEC strains are rather heterogeneous in their biochemical characteristics. Lysine decarboxylase test appeared as the most relevant assay, since all EIEC strains were negative for this enzyme, whereas 66.7% of non-EIEC strains were positive. Other helpful tests performed for strain characterization were: gas production from glucose and from glycerol, sucrose and salicin fermentation, and esculin hydrolysis (p < 0.01). However, strains behaviour was variable with these tests. Differences between both groups of strains with regard to mucate utilization and dulcitol fermentation was significative only to a 5% level. Antibiotic sensitivity patterns showed differences between EIEC and non-EIEC strains: 37.5% of the former vs 80% of the latter, were resistant to at least four of the antibiotics tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

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

1. Age-related change of the branched-chain fatty acid distribution in rat skin surface lipid was studied for 24 months. 2. The proportion of even carbon number iso-acid increased from infancy to month 5 and thereafter decreased with advancing age toward senescence. 3. Concentration of odd carbon number iso-acid depicted a similar shape of time course, but with a lesser magnitude and a peak value at month 1. 4. Anteiso- fatty acid reached the plateau level at month 5 and remained roughly constant through maturity to senescence.

Aging↗

PubMed1991

Correlation between serum concentrations of the branched chain amino- and alpha-keto-acid and the distribution of the branched-chain fatty acids on rat skin surface.

This study described the relationship between the concentration of the branched-chain fatty acid (BCFA) in rat skin surface lipid and the serum level of the branched-chain amino acid (BCAA) and branched-chain alpha-keto acid (BCKA). The concentrations of the BCFAs in the monoester fraction of the skin surface lipid, and BCAAs and BCKAs in the serum were analyzed in rats fed varying amounts of protein (0 to 40%) and different types of BCAAs (3%) for 2 weeks. The serum concentrations of BCAA were proportional to the protein level by day 10 of the feeding period. This dose response was not sustained by day 14 at the end of the feeding. Protein level dependence was not so evident in the concentration of BCKA. The concentrations of BCFA, even carbon number iso-acid in particular, increased in linear proportion to protein intake in the skin surface lipid. Supplementation of valine and isoleucine to the diet at a 3% level specifically raised the concentration of the respective BCAA and corresponding BCKA in serum, and related BCFA in the skin surface lipid. Addition of leucine, however, did not affect the related BCFA concentration in spite of elevated concentration of leucine and its alpha-keto acid. A good linear correlation between the average concentration of the substrates in the circulation and the concentrations of the product BCFA on the skin surface was thus obtained for valine, isoleucine and their respective alpha-keto acid. This relationship did not appear to hold up for leucine and its alpha-keto acid.

Amino Acids, Branched-Chain↗

PubMed1990

Distribution of branched-chain fatty acid in the skin surface lipid of laboratory animals.

1. The distribution of the branched-chain fatty acid (BCFA) was studied in skin surface lipids of laboratory animals (rat, mouse, hamster and rabbit) and the experimental animal for the study of the metabolic fate of BCFA was chosen. 2. The monoester fraction resistant to microbial degradation was the index of which fatty acids were identified and the compositions were analyzed by capillary gas chromatography and mass spectrometry (GC-MS). 3. The contents of monoester fractions in rat, mouse, hamster and rabbit were 78.9, 15.9, 30.4 and 45.6% of the total skin surface lipid, respectively. 4. BCFAs were exclusively identified to be either iso- or anteiso-series type by means of mass spectrometry. 5. The sum of iso- and anteiso-acid was the highest in hamster comprising 53% in male and 38% in female of the monoester acid. 6. Sex related differences of BCFA concentration were not so evident in the other three species. 7. BCFA contents in the monoester fractions were as follows: rat 32%, mouse 25% and rabbit 3%. 8. Concentrations of iso-series fatty acid were consistently higher than that of anteiso-series type in all animals studied. 9. Abundance of 2-hydroxy fatty acid in the rabbit monoester fraction was noted for the first time. 10. Suitability of these laboratory animals for the study of BCFA metabolism was discussed.

Animals↗

PubMed1989

Hypocholesterolemic activity of alpha-amylase hydrolysate of bagasse alkaline extract in rats fed atherogenic diet.

Cholesterol-lowering activity of enzymatic hydrolysate of bagasse alkaline extract was studied in rats fed a cholesterol-enriched diet. The bagasse alkaline extract was found to be vulnerable to the enzymic attack of alpha-amylase. Thus the alkaline extract was degraded into two fractions: long-chain fraction (polysaccharides) and short-chain fraction (oligosaccharides). The long-chain fraction was active in lowering the serum cholesterol level while feeding the short-chain fraction resulted in a slightly elevated serum cholesterol level. The feeding by gavege of the long-chain fraction 12 h after the meal also was effective in lowering serum cholesterol concentration. These findings were compatible with the concept that the bagasse alkaline extract affect the cholesterol dynamics apart from input-output balance of cholesterol. Possible mechanisms responsible for the cholesterol-lowering activity of the extract were discussed.

Amylases↗

PubMed1984

Effects of Okinawan sugar cane wax and fatty alcohol on serum and liver lipids in the rat.

Partially purified Okinawan sugar cane wax and fatty alcohol were fed to Wistar strain rats to examine the effects on serum and liver cholesterol (Chol), triglyceride (TG) and phospholipid (PL). The fecal excretion of neutral sterols in the rats was also determined. There were no significant differences found in the body weight gain, food intake and liver weight among the animals of experimental diet groups. An addition of 0.5% sugar cane wax to the diet significantly lowered the concentrations of serum and liver Chol in the rats. There were no significant differences observed in PL and TG levels either in serum or liver among the experimental groups. These results indicate that cane wax, one of the elements contained in sugar cane rind as well as in black sugar, may have a cholesterol-lowering effect on the serum and liver of the rats. The amount of feces excreted by the three experimental diet groups of rats were exactly the same and also no significant differences were found in the excretion of Chol.

Animals↗

PubMed1983

Separation and partial purification of wax and fatty alcohol from Okinawan sugar cane rind lipids.

A composition analysis of Okinawan sugar cane rind materials was conducted, and it was found that the main components were lipids, crude fiber and water indicating about 27%, 19.6% and 14.6%, respectively. The lipids were effectively extracted from rind materials by benzene. Wax (18%) and fatty alcohol (8%) were found to be the main components, totaling up to 96% of the lipids. Separation and partial purification of wax and fatty alcohol were attempted by means of silica gel column chromatography, thin-layer chromatography (TLC), infrared (IR) absorption spectra and gas-liquid chromatography-mass spectrometry (GC-MS). The major components of the wax were considered to be two compounds with the molecular weights of 408 (C-26) and 436 (C-28), and those of fatty alcohol were di-ol with molecular weights of 440 (C-29) and 468 (C-31). Both wax and fatty alcohol were purified by rechromatography on a silica gel column and the samples obtained seemed to be satisfactory for use in experimental rats' diets.

Fatty Alcohols↗

PubMed1982

Purification and properties of thermostable beta-xylosidase from immature stalks of Saccharum officinarum L. (sugar cane).

Thermostable beta-xylosidase was purified from immature sugar cane stalks to an electrophoretically homogeneous form by ammonium sulfate fractionation, ion-exchange chromatography on DEAE-cellulose and P-cellulose columns, heat treatment (70 degrees C, 20 min) and gel filtration on a Sephadex G-100 column. The purification was about 165-fold in specific activity with a high recovery of 43%. The apparent molecular weight of the enzyme, as determined by gel filtration, was 62,000. In SDS-polyacrylamide gel electrophoresis, the purified enzyme was homogeneous and consisted of only one polypeptide, having a molecular weight of approximately 62,000. The optimum temperature and pH were found to be 75 degrees C and 4.85, respectively. The enzyme was thermostable and especially stable in the presence of D-xylose. The enzyme retained full activity after incubation at 70 degrees C for 60 min in the presence of 0.1% D-xylose and when heated at 75 degrees C in the presence of 1% D-xylose, the enzyme was stable up to 30 min. Among the various sugars tested, D-xylose was found to be most effective stabilizer. The Km and Vmax values were 2.05 mM and 20.4 mumol/mg/min, respectively. The substrate specificity of purified sugar cane beta-xylosidase was investigated with 16 substrates. It was not able to hydrolyze any p-nitrophenyl glycopyranosides, larch wood xylan, or sugar cane except for p- and o-nitrophenyl-beta-D-xylopyranosides. The enzyme hydrolyzed p-nitrophenyl-beta-D-xylopyranoside more rapidly than o-nitrophenyl-beta-D-xylopyranoside. The hydrolysis of p-nitrophenyl-beta-D-xylopyranoside was markedly inhibited by AgNO3, HgCl2, and D-xylose. Competitive inhibition was shown to occur with both HgCl2 and D-xylose. AgNO3 was found to be a non-competitive inhibitor. The enzyme lost 20% of its activity by photo-oxidation in the presence of methylen blue for 8 h. By polyacrylamide disc gel electrophoresis, the enzyme was found to contain carbohydrate. The enzyme was then hydrolyzed and the carbohydrate content found to be 13.5%, the constituent sugars being arabinose and galactose.

Amino Acids↗

PubMed1981

Purification and properties of alpha-galactosidase from immature stalks of Saccharum officinarum (sugar cane).

The immature sugar cane stalks studied contained less than 7% sucrose, and showed the activities of enzymes such as invertase, alpha-galactosidase, alpha-mannosidase, beta-N-acetylglucosaminidase, beta-glucosidase, beta-xylosidase, and beta-galactosidase. The alpha-galactosidase was highly purified by ammonium sulfate fractionation, gel filtration on a Sephadex G-100 column, ionexchange chromatography on DEAE-cellulose, and CM-cellulose columns, and heat treatment (60 degrees C, 15 min) in the presence of 0.2 m D-galactose. In polyacrylamide gel electrophoresis, the purified enzyme was homogeneous, having a molecular weight of approximately 46,000. In gelfiltration, it was approximately 47,000. The activity was optimum at pH 4.5 and at 60 degrees C. The purified enzyme hydrolyzed p-nitrophenyl-alpha-D-galactopyranoside (Km, 0.83 mM; Vmax, 25.0 mumol/mg/min), raffinose (Km, 25.9 mM; Vmax, 15.4 mumol/mg/min), and stachyose (Km, 13.0 mM; Vmax 2.7 mumol/mg/min), in addition to melibiose, guar gum, and locust bean gum. The hydrolysis of p-nitrophenyl-alpha-D-galactopyranoside was markedly inhibited by HgCl2, AgNO3, p-chloromercuribenzoate (PCMB), L-ascorbic acid, melibiose, stachyose, and D-galactose. Also the purified enzyme showed a lectin activity with trypsinized erythrocytes.

Chemical Phenomena↗

PubMed1981

Effects of Okinawan sugar cane rind on serum and liver cholesterol and triglyceride levels in the rat.

Okinawan sugar cane rind was fed to Wistar strain rats to examine its effects on the serum and liver cholesterol (Chol) and triglyceride (TG). At the same time, the effects of sugar cane rind on the fecal excretion of neutral sterols of the rats were examined. There were no significant differences found in the food intakes and the liver weight between the rats fed with sugar cane rind and other groups. The addition of 1% Chol to the diet caused a significant increase in body weight gain but the supplementation of sugar cane rind (2%) showed an effect on weight control of rats. The serum Chol and TG levels of the rats given sugar cane rind were lowered significantly. However, the lipid levels in the liver were almost the same when compared with the control groups. The amount of feces excreted by the rats fed with sugar cane rind was about 37% more than that of the control group, and the fecal excretion of neutral sterols was significantly higher.

Animals↗