Biomedical subjects

I Chinen

Publications and source records attributed to I Chinen.

At least 19 recordsLinked to original sources

PubMed2006

Characterization and epidemiologic subtyping of Shiga toxin-producing Escherichia coli strains isolated from hemolytic uremic syndrome and diarrhea cases in Argentina.

Argentina has a high incidence of hemolytic uremic syndrome (HUS); 12.2 cases per 100,000 children younger than 5 years old were reported in 2002. Shiga toxin (Stx)-producing Escherichia coli (STEC) is the primary etiologic agent of HUS, and STEC O157 is the predominant serogroup isolated. The main objective of the present work was to establish the phenotypic and genotypic characteristics of the STEC strains in general isolated from Argentine children during a prospective study and the clonal relatedness of STEC O157:H7 strains using subtyping techniques. One hundred and three STEC strains isolated from 99 children were included. The phenotypic and genotypic features were established, and a polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) was performed to determine stx2 variants. The clonal relatedness of E. coli O157 isolates was established by phage typing and pulsed-field gel electrophoresis (PFGE). The 103 STEC strains belonged to 18 different serotypes, and 59% were of serotype O157:H7. Stx2 was identified in 90.3%, and stx1 in 9.7%. Among the 61 STEC O157 strains, 93.4% harbored the stx2/stx2vh-a genes; PT4 (39.3%) and PT2 (29.5%) were the predominant phage types. Using PFGE with the enzyme XbaI, a total of 41 patterns with at least 80% similarity were identified, and seven clusters with identical profiles were established. Some of the clusters were further split by PFGE using BlnI as the second enzyme. Isolates with indistinguishable PFGE patterns were with one exception also indistinguishable by phage typing and stx genotyping. These findings confirmed that some isolates were genetically related. However, no epidemiological linkages were identified. STEC strains with different genotypes and belonging to diverse serotypes were isolated in Argentina. Some STEC O157 strains could not be distinguished by applying subtyping techniques such as PFGE and phage typing.

Argentina↗

PubMed2006

Outbreaks of avian cholera in Hope Bay, Antarctica.

During austral summers 1999-2000 and 2000-01, two outbreaks of avian cholera occurred in the Hope Bay area (63 degrees 24'S, 56 degrees 59'W), located on the tip of the Antarctic Peninsula. Eighty-six dead birds were found: five kelp gulls (Larus dominicanus), 36 skuas (Stercorarius sp.), and 45 Adelie penguins (Pygoscelis adeliae). The carcasses were studied using clinical, pathological, and microbiological criteria. Water samples from ponds where birds were settled and samples from 90 healthy birds also were analyzed during the second outbreak. Pasteurella multocida isolates were identified by biochemical tests, capsular type, somatic serotype, and susceptibility to nine antibiotics. Molecular subtyping was performed by ApaI and SmaI pulsed-field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus (ERIC-PCR). In February 2000, mortality in skuas was 16% and 2% in kelp gulls. In the 2000-01 breeding season, mortality in south polar skuas was 47%, 24% in brown skuas, 1.4% in kelp gulls, and 0.01% in Adelie penguins. All birds had lesions of avian cholera. In kelp gulls the presentation was chronic, whereas skuas and penguins suffered subacute and acute disease, respectively. Fifty-five isolates recovered from dead birds and one from water were identified as P. multocida gallicida, type A:1. The strains presented a unique molecular pattern by PFGE and ERIC-PCR. A possible hypothesis to explain the origin of the outbreaks was that nonbreeder kelp gulls carried P. multocida gallicida to Hope Bay, and avian cholera was transmitted through water to skuas and penguins. This study reports avian cholera in new bird species, their potential role in the transmission of the disease, and the different responses of these species to the disease.

Animals↗

PubMed2003

Isolation and characterisation of Shiga toxin-producing Escherichia coli O157:H7 from calves in Argentina.

Four hundred and twenty-two calves were examined for intestinal carriage of Shiga toxin-producing Escherichia coli O157:H7 using conventional plating. Two (0.5%) E. coli O157 were recovered. They were compared with 96 Argentine strains of different origin by pulsed-field gel electrophoresis, phage typing and PCR-RFLP of stx2 genes. One strain isolated from a calf, was closely related with 18 strains of clinical origin.

Animals↗

PubMed2003

Avian cholera in a southern giant petrel (Macronectes giganteus) from Antarctica.

A southern giant petrel (Macronectes giganteus) was found dead at Potter Peninsula, King George Island, South Shetland, Antarctica. The adult male was discovered approximately 48 hr after death. Macroscopic and microscopic lesions were compatible with avian cholera and the bacterium Pasteurella multocida subsp. gallicida, serotype A1 was isolated from lung, heart, liver, pericardial sac, and air sacs. In addition, Escherichia coli was isolated from pericardial sac and air sacs. This is the first known report of avian cholera in a southern giant petrel in Antarctica.

Animals↗

PubMed2001

Effects of water-soluble hemicellulose from soybean hull on serum antibody levels and activation of macrophages in rats.

Effects of soybean hull water-soluble hemicellulose (WSHC) on serum immunoglobulin (Ig) concentration and production of NO and IL-1beta from peritoneal macrophages were examined and compared with those of Agaricus blazei in the rat system. WSHC consisted of arabinose, galactose, xylose, glucose, and rhamnose, and the molecular weight was approximately 500000. Rats were ip administrated each sample at a dose of 0.67, 13.4, or 26.9 mg/kg/day for 14 days. The administration of WSHC resulted in significantly higher productions of IgM (p < 0.01 on day 6, p < 0.05 on day 14) and IgG (p < 0.05 on day 6) than those in other groups. When peritoneal macrophages were stimulated with various concentrations of sample (0.67, 13.4, or 26.9 mg/mL), WSHC significantly increased both NO and IL-1beta productions only at the concentration of 13.4 (mg/mL) compared with those of a saline group. These findings demonstrate that WSHC enhances humoral immunity and activation of macrophages, thereby leading to the augmentation of immune responses in rats.

Agaricus↗

PubMed2001

Isolation and characterization of Escherichia coli O157:H7 from retail meats in Argentina.

Between February and May 2000, 279 meat samples were collected from 136 retail stores in Gualeguaychú City, Argentina. Samples were assayed for Escherichia coli O157:H7 by selective enrichment in modified EC broth containing novobiocin, followed by immunomagnetic separation (IMS) and plating onto both sorbitol MacConkey agar supplemented with cefixime and potassium tellurite and a chromogenic medium. Eleven E. coli O157:H7 isolates were detected in 6 (3.8%) of 160 ground beef samples, in 4 (4.8%) of 83 fresh sausages, and in 1 (3.3%) of 30 dry sausages. E. coli O157:H7 was not isolated from five hamburger patties or one barbecue-type fresh sausage assayed. The isolates were tested for virulence-related genes. Ten additional Shiga toxin-producing E. coli (STEC) O157:H7 isolates of food origin, recovered from different locations in Argentina, were included for comparison purposes. All 21 isolates harbored both eae and EHEC-hlyA genes, and 12 (57.1%) encoded stx2/stx2vh-a. The isolates were of phage types 87 (seven strains), 14 (four strains), 4 (three strains), and 26 (one strain). Six strains were nontypable by phage typing. Pulsed-field gel electrophoresis (PFGE) revealed 19 XbaI-PFGE profiles. Fifteen (71%) strains were grouped in four clusters, which shared more than 80% of DNA restriction fragments. The enrichment culture method with IMS was a sensitive procedure to detect E. coli O157:H7 strains in retail meats. Some of the isolates from different stores presented a high clonal relatedness, as determined by XhaI-PFGE and phage typing, and harbored the virulence factors associated with human illness.

Argentina↗

PubMed2000

The major low molecular weight apolipoprotein from normal and hyperlipidemia atherosclerosis-prone (LAP) Japanese quail.

The low molecular weight (LMW) apolipoprotein of apo C plays an important role in the metabolism of triglyceride-rich lipoproteins. This study aimed at a characterization of the major LMW apolipoproteins from normal quail strain, and also from LAP (hyperlipidemia atherosclerosis-prone) strain to identify its genetic disorder. The major LMW apoprotein cDNA clone from normal quail comprised of approximately 500 bp, and encoded polypeptide of 78 amino acid residues containing 57 amino acids as a mature apolipoprotein. Although the quail LMW apoprotein showed a low homology to either apo C-I, C-II, or C-III of other animals, it retained a well-developed amphipathic alpha-helix structure. There was no difference in the deduced primary structure of the quail LMW apoprotein between LAP and normal strain. An analysis of the mRNA expression showed that the quail LMW apoprotein was only expressed in the liver of both LAP and normal Japanese quail. No difference was noted in the hepatic expression of the quail LMW apoprotein mRNA between normal and LAP strains with neither normal nor atherogenic dietary conditions. The structure and expression of the major LMW apoprotein thus had no relevance to higher susceptibility of LAP strain to the experimental atherosclerosis.

Amino Acid Sequence↗

PubMed2000

Biased distribution of the branched-chain fatty acids in ceramides of vernix caseosa.

The compositions of ester- and amide-linked fatty acids from ceramides of human vernix caseosa were described with emphasis on the distribution of the branched-chain fatty acid (BCFA). Two novel ceramides were isolated from vernix caseosa in the course of this study: the acylated type of esterified alpha-OH-hydroxyacid/sphingosine ceramide (Cer[EAS]) and nonacylated type of non-OH fatty acid/hydroxysphingosine ceramide (Cer[NH]). Their chemical structures were identified by nuclear magnetic resonance and chemical procedure. The Cer[EAS] was an acylceramide and consisted of the highest concentrations of ester- and amide-linked BCFA (62 and 67%, respectively). The iso- or anteiso-branching structures of the aliphatic chains were confirmed by the mass spectra of their picolinyl or pyrrolidide derivatives. As a whole, amide-linked fatty acids of ceramides 1-7 and Cer[NH] were normal types of straight-chain fatty acids with or without alpha- or omega-hydroxylation. The BCFA concentrations of amide-linked fatty acids in these ceramides (ceramides 1-7 and Cer[NH]) were low and less than 10%. The BCFA thus occurred exclusively in a novel acylceramide of Cer[EAS] in the vernix caseosa.

Ceramides↗

PubMed2000

cDNA cloning and molecular analysis of papaya small GTP-binding protein, pgp1.

In the course of papaya EST collection, one clone (pRA4-3) encoding partial sequence of papaya small GTP-binding protein gene, pgp1, was obtained. Based on the sequence information of pRA4-3, the entire coding region of pgp1 was cloned using the 3'RACE PCR technique. ORF of pgp1 is 636bp long and deduced molecular weight of the protein is 23,311. Phylogenetic analysis showed that PGP1 belongs to YPT/RAB group of the small GTP-binding protein and is a homologue of RAB2. Southern analysis showed that there are several pgp1-related genes in papaya genome. Northern analysis showed that pgp1 was expressed equally in stems of seedlings that were grown under light and dark conditions. This result shows that PGP1 is not involved in the phytochrome-mediated signal transduction as an auxin signal transducer in stems of papaya seedlings.

Amino Acid Sequence↗

PubMed1999

Further optimization of culture method for rat keratinocytes: titration of glucose and sodium chloride.

The present study further improved the serum-free method of culturing rat keratinocytes. To obtain the best growth of rat keratinocytes, we modified our previous serum-free medium (MCDB153 based medium), particularly the amounts of glucose and sodium chloride (NaCl). Titration experiments showed the optimal concentration to be 0.8 mM for glucose and 100 mM for NaCl. This modification eliminated the requirement for albumin, which had been essential for colony formation when our previous medium was used. Titration of glucose and NaCl, followed by adjustment of essential amino acids and growth factors, produced a new formulation. More satisfactory and better growth was achieved with the new medium than with the previous medium. Accumulation of monoalkyldiacylglycerol (MADAG) was consistently noted in this study, representing the unusual lipid profile. A tendency toward normalization was, however, noted with the neutral lipid profile of keratinocytes cultivated in the new medium: lower production of MADAG was obtained with the new formulation, rather than the previous one.

Amino Acids↗

PubMed1999

Apolipoprotein A-I of hyperlipidemia atherosclerosis prone (LAP) quail: cDNA sequence and tissue expression.

Apolipoprotein A-I (apo A-I) has an important role in the transport of cholesterol. This study describes the complete nucleotide and deduced amino acid sequence for apo A-I of LAP quail. A full length apo A-I cDNA clone for hyperlipidemia atherosclerosis prone (LAP) quail was isolated from a lambda gt10 liver cDNA library. The DNA sequence of LAP apo A-I cDNA was similar to that of normal Japanese quail. The deduced amino acid sequence of LAP apo A-I was hence identical to that of normal Japanese quail. LAP apo A-I mRNA is about 1.4 kilobases in length and expressed in a variety of tissues including small intestine, liver, lung, breast muscle, testis, and heart. Although the tissue distribution of apo A-I was similar between strains, LAP quail expressed more apo A-I mRNA than normal Japanese quail in all tissues examined. This tendency was pronounced with the small intestine. Although the concentration of serum apo A-I did not correlate with the tissue expression of mRNA, the observation may suggest that the increased apo A-I expression in LAP strain had some relevance to the susceptibility of this strain to the experimental atherosclerosis.

Amino Acid Sequence↗

PubMed1998

Osteopathy in broiler chicks fed toxic mimosine in Leucaena leucocephala.

Further studies of mimosine toxicity in broiler chicks were done to clarify a possibility of osteopathy. The mineral content and density of femur and the strength, ductility, and toughness for the index of mechanical properties significantly decreased in the 1% mimosine group, compared with those in the control and restricted groups. The stiffness had a decreasing tendency in the 1% mimosine group. Consequently, it was concluded that chicks fed ad libitum a 1% mimosine diet for 12 days developed osteopathy. The bone mineral density and the strength of the restricted group were lower than those of the control group, and those of the 1% mimosine group were still lower than those of the restricted group. Contents of pyridinoline and deoxypyridinoline in the excrement were significantly higher in the restricted group than those in the control group, but the contents in the 1% mimosine group were significantly lowest among the groups. Osteopathy in chicks fed mimosine, therefore, seemed to be done by loss of appetite and changing to a low turnover of bone caused by mimosine.

Amino Acids↗

PubMed1998

NADH-dependent inhibition of branched-chain fatty acid synthesis in Bacillus subtilis.

Addition of NADH to crude but not to pure branched-chain alpha-keto acid decarboxylase decreased the CO2 production from alpha-keto-beta-methylvalerate (KMV) suggesting the presence of an NADH dependent inhibitor in the crude enzyme from Bacillus subtilis. This NADH-dependent decarboxylase inhibitor was purified to homogeneity by a fast protein liquid chromatography system. The purified inhibitor was identical with leucine dehydrogenase as to N-terminal amino acid squence (35 residues) and molecular weight, and catalyzed the oxidative deamination of three branched chain amino acids (BCAAs), valine, leucine, and isoleucine. The decarboxylase inhibitor was therefore identified as leucine dehydrogenase. A decreased substrate availability caused by leucine dehydrogenase thus reasonably accounted for the NADH dependent inhibition of the decarboxylation. In turn, the observation that leucine dehydrogenase competes with the decarboxylase for branched-chain alpha-keto acid (BCKA) suggested an involvement of this enzyme in the branched chain fatty acid (BCFA) biosynthesis. This view was supported by the observation that addition of NAD to crude fatty acid synthetase increased the incorporation of isoleucine into BCFAs. Pyridoxal-5'-phosphate and alpha-ketoglutarate, cofactors for BCAA transaminase, modulated BCFA biosynthesis from isoleucine in vitro, suggesting also the involvement of transaminase reaction in BCFA biosynthesis.

Acyltransferases↗

PubMed1997

Apolipoprotein A-1 of Japanese quail: cDNA sequence and modulation of tissue expression by cholesterol feeding.

Apolipoprotein (apo) A-1 cDNA was amplified by the reverse-transcriptase-polymerase chain reaction (RT-PCR). Primers were synthesized according to the nucleotide sequence of chicken apo A-1, and the identity of apo A-1 cDNA was confirmed by comparing with the N-terminal amino acid sequence. The open reading frame of apo A-1 cDNA consists of 795 nucleotides, and it is capable of coding a polypeptide of 264 amino acids. A comparison between quail and chicken apo A-1 revealed 94.5% homology in the nucleotide sequence and 91.7% homology in the amino acid sequence. There was a similar 11- or 22-amino acid repeat in quail apo A-1 as was the case for chicken apo A-1. Apo A-1 mRNA was evaluated to be 1.4 k in length and was expressed in various tissues of Japanese quail: the liver, small intestine, lung, kidney, heart, and muscle. A quantitative evaluation, however, revealed that the liver and small intestine were the major organs for apo A-1 synthesis, accounting for more than 90% of the total expression of apo A-1 mRNA. Besides apo A-1 mRNA (1.4 k in length), a transcript of 4.1 k was detected in all the tissues examined, with a magnitude ranging from 5 to 10% of the apo A-1 mRNA level. The effect of cholesterol level on the expression of apo A-1 mRNA was studied to address the physiological significance of apo A-1 in the liver, small intestine, and muscle. The level of cholesterol in the liver and breast muscle was increased by feeding with cholesterol and reached a saturation level at day 7. There was also a temporal rise of cholesterol level at day 7 in the small intestine. Dietary cholesterol increased the expression of apo A-1 mRNA two fold in both the liver and small intestine. This was not the case for breast muscle, in which the expression of apo A-1 mRNA was not modulated by the cholesterol level.

Amino Acid Sequence↗

PubMed1997

Lipoprotein and apoprotein profiles of hyperlipidemic atherosclerosis-prone Japanese quail.

The purpose of this study was to characterize the lipoprotein and apoprotein profiles of hyperlipidemic atherosclerosis-prone (HAP) Japanese quail. HAP and commercially available (CA) Japanese quail were fed either a semi-purified diet containing 1% cholesterol or a cholesterol-free diet for two weeks. The lipoproteins of CA and HAP quail fed cholesterol-free diet were composed of two fractions: densities ranging from 1.02 to 1.09 and from 1.09 to 1.21. The lipoprotein distribution patterns obtained from both strains showed an HDL-predominant pattern. A protein of 26 kDa was the major apoprotein in the entire density range of the lipoprotein class. Marked increases in the cholesterol ester levels were observed in the lower density fractions (1.006 < d < 1.055: chylomicron and VLDL fractions) of the cholesterol-fed quail, accounting for 46% of the total lipids in CA quail and 54% in HAP quail. In addition, the presence of a protein of 470 kDa was exclusively observed in the lower density fractions (1.006 < d < 1.055) of the cholesterol-fed HAP quail. The fatty-acid compositions of the chylomicron and VLDL fractions were affected by the dietary cholesterol in both strains: a decrease in concentration of 16: 0 and increase in 18: 0 (weight %). However, cholesterol feeding had no effect on the level of cholesterol, chemical composition or fatty-acid composition of the HDL fractions in either strain. Although the lipoprotein and apoprotein profiles of HAP quail showed resemblances to those of the CA quail, expression of the 470 kDa protein in the lipoproteins (d < 1.055) appeared to be pronounced in HAP quail. The relevance of these lipoprotein and apoprotein profiles to the genesis of atherosclerosis was discussed in this study.

Animals↗

PubMed1996

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

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

Acetates↗

PubMed1996

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

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

Age Factors↗

PubMed1996

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

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

Animals↗