bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resistance of the insulinotropic action of α‐D‐glucose and β‐L‐glucose pentaacetates to cholera and pertussis toxins
Authors: Malaisse Willy J. , Ladriere Laurence 
Published: July 2007

AbstractThe pentaacetate esters of α‐D‐glucose and β‐L‐glucose were recently reported to stimulate insulin release. The possible participation of G‐protein‐coupled receptors to the insulinotropic action of these esters was investigated in rat pancreatic islets either preincubated with cholera toxin or obtained from animals injected with pertussis toxin. Neither procedure affected adversely the secretory response to the esters in islets incubated in the presence of L‐leucine. Thus, in both situations, α‐D‐glucose pentaacetate and, to a lesser extent, β‐L‐glucose pentaacetate augmented insulin release evoked by the branched‐chain amino acid, whilst β‐L‐galactose pentaacetate failed to do so. These findings suggest that G‐proteins sensitive to either cholera or pertussis toxins are not involved in one of the two modalities by which these esters are thought to stimulate insulin secretion, namely that independent of the catabolic fate of their hexose moieties.
Signal transduction by the peptide which mimics the activity of thrombopoietin
Authors: Kimura Tatsuya , Kaburaki Hiroshi , Tsujino Tomomi , Watanabe Yoshinari , Kato Hideo 
Published: July 2007

AbstractThrombopoietin (TPO) plays a central role in megakaryopoiesis and platelet production. It is a ligand for c‐mpl, which is a member of the hematopoietic receptor superfamily. We have recently identified several human c‐mpl binding peptides which are distinct from TPO, from phage random peptide libraries. PK1M is one of these peptides and is an agonist of c‐mpl which is TPO receptor. We show here that PK1M induces the tyrosine phosphorylation of the Janus kinase 2 (JAK2) and the activation of the signal transducer and activation of transcription 5 (STAT5) in TPO‐dependent cells like TPO.
Branched‐chain α‐keto acid dehydrogenase kinase content in rat skeletal muscle is decreased by endurance training
Authors: Fujii Hisao , Shimomura Yoshiharu , Murakami Taro , Nakai Naoya , Sato Tasuku , Suzuki Masashige , Harris Robert A. 
Published: July 2007

AbstractThe activity state of branched‐chain α‐keto acid dehydrogenase complex in skeletal muscle was elevated by running exercise in trained and untrained rats, but level of this elevation was significantly greater in the former than in the latter. To elucidate the mechanism of the training effect on the exercise‐induced activation of the complex, a protein amount of branched‐chain α‐keto acid dehydrogenase kinase, which is responsible for inactivation of the complex by phosphorylation, in the muscle was measured by the Western blot analysis. Endurance training decreased the content of the kinase protein in the muscle by ∼30%, suggesting that this decrease is involved in the mechanisms for greater activation of the complex by exercise in trained rats.
A method for uni‐directional reconstitution of human erythrocyte glucose transporter
Authors: Xiao L. , Xie W. S. , Yang F. Y. 
Published: July 2007

AbstractThe glucose transporter of human erythrocytes (Glutl) was reconstituted into soybean phospholipid liposomes by a method of direct incorporation using the nonionic detergent n‐octyl β‐D‐glucopyranoside. The reconstituted proteoliposomes were proved to be intact and low ionic permeability. Freeze‐fracture electron microscopy study showed that the diameter of the proteoliposomes was about 150±50 nm and the protein was randomly distributed. The kinetic parameters of the reconstituted transporter were: Km=16.23 mmol/L, Vmax=34.48 nmol/sec.mg protein. Furthermore, about 90% of the glucose transporter in the reconstituted proteoliposomes were orientated inside‐out. Until now it is a more efficient method for uni‐directional reconstitution of Glut 1 with good reproducibility and higher transport activity.
Attenuated antigenicity of ribonucleoproteins modified by reactive oxygen species
Authors: Waris Ghulam , Alam Khurshid 
Published: July 2007

AbstractRibonucleoprotein (RNP) particles isolated from fresh goat fiver nuclei were exposed to hydroxyl radical which induced modification in the gross structure of RNP particles. To evaluate the effect of hydroxyl modification on the antigenic properties of RNP and possible role of ROS‐RNP in the initiation and development of SLE, enzyme immunoassays were carried out. SLE sera having high titre anti‐DNA antibodies showed enhanced binding to hydroxyl modified RNP particles in comparison to unmodified RNP particles. In competition assay none of the SLE sera or isolated IgG showed preference for ROS‐modified RNP particles over native RNP particles. These studies suggest that anti‐RNP autoantibodies observed in subpopulation of SLE patients are generated by some other intra‐or extracellular mechanisms and hydroxyl radical has probably no direct role in the initiation of antibodies.
Hormone‐induced changes in cardiolipin from leydog cells: Possible involvement in intramitochondrial cholesterol translocation
Authors: Gasnier Françoise , Rey Catherine , Graverand Marie‐Pierre Hellio Le , Louisot Pierre , Benahmed Mohamed 
Published: July 2007

AbstractThe rate‐limiting and hormonally regulated step in steroid hormone biosynthesis is the delivery of cholesterol from the outer to the inner mitochondrial membrane where cytochrome P450scc resides. Although the exact mechanism of intramitochondrial cholesterol translocation remains unknown, the formation of contact sites between outer and inner mitochondrial membranes appears as a necessary component for cholesterol transfer. Several pieces of evidence suggest that local formation of intermembrane contact is a consequence of a non‐bilayer arrangement of polymorphic lipids which are enriched in the junctions. As a step toward clarifying mitochondrial contact sites formation and thus cholesterol translocation in steroidogenic cells, we have undertaken studies to identify the factors which might result in non‐bilayer structure to be adopted by mitochondrial phospholipids on stimulation of MA‐10 Leydig cells. Our results demonstrate that an increase in the unsaturation of the cardiolipin acyl groups on hormonal stimulation might favor the formation of non‐bilayer adhesion points.
Methionine modification impairs the C5‐cleavage function of cobra venom factor‐dependent C3/C5 convertase
Authors: Fu Qinglan , Gowda D. Channe , McPhie Peter 
Published: July 2007

AbstractThe complement‐mediated lysis of guinea pig erythrocytes by cobra venom factor (CVF) decreased by 50‐60% within 2 min of treatment with 5 mM sodium periodate at 0 °C. This loss of activity paralleled modification of 3‐4 Met; other amino acids and sugar residues of the oligosaccharide chains were not affected. Treatment with N‐chlorosuccinimide or chloramine‐T under conditions that specifically modified 3‐4 readily‐oxidizable Met also caused 50‐60% loss of CVF activity. The secondary structure of CVF was not altered by these modifications. Methionine‐modified CVF (MetCVF) supported the cleavage of factor B by factor D with equal efficiency as that of untreated CVF to form C3/C5 convertase (MetCVF,Bb) of the alternative pathway. MetCVF,Bb and CVF,Bb were indistinguishable with respect to C3 cleavage. However, the C5‐cleavage ability of MetCVF,Bb was significantly lower than that of CVF,Bb. These results suggest the involvement of Met in CVF binding of C5.
The prevention of carbon tetrachloride‐induced hepatotoxicity in mice by α‐hederin: Inhibiton of cytochrome P450 2E1 expression
Authors: Jeong Hye Gwang , Park Hyeon Yong 
Published: July 2007

AbstractThe protective effects of α‐Hederin on carbon tetrachloride‐induced hepatotoxicities were investigated in mice. Pretreatment with α‐Hederin prior to the administration of carbon tetrachloride significantly prevented the increase in serum alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) activity and lipid peroxidation in a dose dependent manner. Hepatic glutathione levels and glutathione‐S‐transferase activities were not affected by pretreatment with α‐Hederin alone but pretreatment with α‐Hederin protects carbon tetrachloride‐induced depletion of hepatic glutathione levels. The effects of α‐Hederin on the cytochrome P450 (P450) 2E1, the major isozyme involved in carbon tetrachloride bioactivation were investigated, α‐Hederin markedly decreased the P450 2E1‐specific activities of p‐nitrophenol and aniline hydroxylation in a dose‐dependent manner. Consistent with these observations, the P450 2E1 expressions were also decreased, as determined by immunoblot analysis. These results demonstrate that treatment of mice with α‐Hederin decreases the expression and activities of P450 2E1 enzyme, and reduces biotransformation of carbon tetrachloride, and diminished carbon tetrachloride‐induced liver injury.
Cross‐species reactivity of a monoclonal antibody against glutathione S‐transferase fusion protein of human β2‐adrenergic receptor
Authors: Shin Chan Young , Kang Suk‐jo , Song Mi‐ryoung , Park Kyu Hwan , Seo Dong Ook , Cheong Jae Hoon , Ko Kwang Ho 
Published: July 2007

AbstractThe purpose of the present study was to produce and characterize a monoclonal antibody against human β2‐adrenergic receptor. Male BALB/c mice were immunized with glutathione S‐transferase (GST) fusion protein of the C‐terminal portion of the human β2‐adrenergic receptor which was expressed in E.Coli. The immunized splenocytes were fused with myeloma SP2/0‐Ag14 cells and the resulting monoclonal antibody was named as mAbβC02. The monoclonal antibody βC02 was determined as IgM subtype and then purified by anti‐mouse IgM‐agarose affinity chromatography. The results of ELISA, Western blot, and immunocytochemistry showed that mAbβC02 recognized human β2‐adrenergic receptor in the β2‐adrenergic receptor‐GST fusion protein and human epidermoid carcinoma cell line A431 with highly specific immunoreactivity. In addition, mAbβC02 showed cross‐species reactivity against β‐adrenergic receptor of hamster lung and rat brain as revealed by Western blot and immunohistochemistry. The monoclonal antibody βC02 may provide useful tools for the study of the β‐adrenergic receptor of human and other species including rats.
Inhibition of NF‐κB/Rel nuclear translocation by dexamethasone: Mechanism for the inhibition of iNOS gene expression
Authors: Jeon Young Jin , Han Seung Hyun , Lee Yong Woo , Yea Sung Su , Yang Kyu‐Hwan 
Published: July 2007

AbstractThe decrease in NO production was found to correlate well with a decrease in inducible nitric oxide synthase (iNOS) mRNA expression as demonstrated by Northern blot analysis and quantitative RT‐PCR. Since the promoter in iNOS gene contains binding motifs for NF‐κB/Rel, NF‐IL6, and Oct which appear to be important for LPS‐mediated iNOS induction, the effects of DEX on the activation of these transcription factors were examined. Treatment of DEX to RAW 264.7 cells induced a dose‐related inhibition of NF‐κB/Rel in chloramphenicol acetyltransferase activity, while NF‐IL6 or Oct activation was not affected by DEX. Treatment of RAW 264.7 cells with DEX inhibited DNA binding of NF‐κB/Rel proteins to their cognate DNA site as measured by electrophoretic mobility shift assay. In addition, DEX treatment caused a significant reduction in nuclear c‐rel, p65, and p50 protein contents, and these decreases were paralleled by the accumulation of cytoplasmic c‐rel, p65, and p50. These results suggest that DEX may inhibit iNOS gene expression by a mechanism involving the blockade of LPS‐induced nuclear translocation of NF‐κB/Rel.
Production and purification of an extracellular cellulase from Bacillus brevis vs‐1
Authors: Singh Vinay K. , Kumar Anil 
Published: July 2007

AbstractA bacteria identified as Bacillus brevis has been isolated from the soil. It has been found to secrete cellulase extracellularly whose production increased almost five times on addition of galactose in the culture medium. Production of cellulase has been found optimal at pH 5.5, 37°C and 175 rpm speed using environmental orbital shaker. The cellulase has been purified using ultrafiltration and Sephadex G‐200 column chromatography. The native molecular weight of the enzyme is found to be 33,000±2000 using Sephadex G‐200 gel filtration chromatography. The subunit molecular weight (33,000±2,000) indicate monomeric nature of the enzyme. The enzyme showed Michaelis Menten kinetics exhibiting Km ≈︁1.7±0.1 mg/ml for CMC. The enzyme activity got inhibited by heavy metals viz. Hg+2 and Ag+2
Immunological studies on DNA‐lysine photoadduct
Authors: Islam Najmul , Ali Rashid 
Published: July 2007

AbstractCalf thymus native DNA was covalently linked with lysine by irradiation with 254 nm light. Thermal melting studies indicated a decrease of 16°C in the Tm of DNA‐lysine photoadduct over native DNA. The decrease in Tm was dependent of irradiation dose. The photoadduct was found to be a potent immunogen in experimental animal. Thymine‐lysine photoconjugate in DNA‐lysine photo‐monoadduct appears to be the major immunodominant portion. A strong recognition of DNA‐lysine photoadduct was observed with anti‐DNA autoantibodies found in the sera of patients with SLE. Thymine‐lysine conjugate in DNA‐lysine photo‐monoadduct appears to provide an immunodominant epitope(s) for SLE autoantibody recognition. The results suggests for the possible involvement of DNA‐lysine photoadduct or similar modified structure(s) as a potential trigger for anti‐DNA autoantibody production.
Comparison of inactivation and conformational changes of native and apo yeast alcohol dehydrogenase during thermal denaturation
Authors: Yang Yi , Chen Rong , Zhou Hai‐Meng 
Published: July 2007

AbstractThe conformational changes of native and apo yeast alcohol dehydrogenase during thermal denaturation have been followed by fluorescence emission and circular dichroism spectra. A comparison of inactivation and conformational changes during thermal denaturation shows that for the native enzyme and for the apo‐I YADH which has the conformational zinc removed, the extent of inactivation was larger than the extent of conformational changes at the same temperature. This result supported the suggestion by Tsou (Trends Biochem. Sci. 1986, 11, 427‐429: Science 1993, 262, 380‐381) that the enzyme active site is more flexible. The results also show that apo‐I YADH without the conformational zinc was more easily inactivated with increasing incubation temperature, indicating that the stability of the apo‐I YADH decreased. Kinetic analysis suggest that the substrate does not provide any protective effect during thermal inactivation of native and apo‐I YADH.
Binding of naturally occurring anti‐DNA antibodies to estradiol
Authors: Ali Asif 
Published: July 2007

AbstractBinding of naturally occurring human anti‐DNA autoantibodies to β‐estradiol and native DNA has been investigated. Sera from seven SLE patients were tested for their reactivity with β‐estradiol and native calf thymus DNA. Solid Phase enzyme immunoassay was performed using both colorigenic and fluorogenic substrates. The results show enhanced binding of human anti‐ DNA autoantibodies to β‐estradiol as compared to native DNA. This was further substantiated by increased binding of affinity purified SLE IgG to β‐estradiol. These results suggest a role for female sex hormone in the etiopathogenesis of SLE and are significant vis‐a‐vis female predominance of SLE.
Modulation of erythrocyte photohemolysis rate by glutathione reductase inactivating alkylating agents
Authors: Kersene Regina , Maroziene Audrone , Kliukiene Regina , Anusevicius Zilvinas , DidZiapctriene Janina , Cenas Narimantas 
Published: July 2007

AbstractIn order to determine the rote of glutathione reductase (GR) in protection against AI‐phtalocyanine tetrasulfonate‐sensitized human erythrocyte photolysis, we have studied the effects of antitumour alkylating agents that inactivate GR, on photohemolysis rate. The rates of inactivation of reduced GR decreased in order BCNU > pharanox (N‐p‐[bis‐(2‐chloroethyl)‐amino]‐phe‐nylacetic acid N‐oxide) > phenalol (N‐p‐[bis‐(2‐chloroethyl)‐amino]‐phenylacetyl‐L‐phenylalanine) > o‐F‐ and p‐F‐lophenal (o‐ and p‐isomers of N‐p‐[bis‐(2‐chloroethyl)‐amino]‐phenylacetyl‐D,L‐fluorophenylalanine) > D,L‐melphalan. As supposed, erythrocyte photolysis was accelerated by BCNU and pharanox, however, it was slowed down by phenylalanine mustards. The latter effect was explained by singlet oxygen quenching and/or photooxidation reactions of these compounds. This points out to a possibility of certain phenylalanine derivatives to neutralize the side‐effects of photodynamic therapy.
Effects of D‐glucose and starvation upon the cyclic ADP‐ribose content of rat pancreatic islets
Authors: Scruel O. , Wada T. , Kontani K. , Sener A. , Katada T. , Malaisse W. J. 
Published: July 2007

AbstractRat pancreatic islets were found to display a much lower content of immunoreactive CD38 and a much lower ADP‐ribosyl cyclase activity than rat spleen or brain. Cyclic ADP‐ribose was also measured by a radioimmunological procedure in rat pancreatic islets. In fed rats, the cyclic ADP‐ribose content appeared higher after isolation of the islets in the presence of 2.8 mM D‐glucose rather than in the absence of the hexose, progressively increased during incubation of the islets for 5‐60 min at 37°C, but failed to be affected by the concentration of D‐glucose (zero to 20.0 mM) in the incubation medium. In rats fasted for 24 hours, the cyclic ADP‐ribose islet content also increased during incubation, but again failed to be affected by the concentration of D‐glucose in the incubation medium. Although these findings indicate that the islet cyclic ADP‐ribose content is influenced by nutritional and environmental factors, they do not support the view that the insulinotropic aciton of D‐glucose involves major change in the islet cell content of the cyclic nucleotide.
Purification and partial characterization of cathepsin D from porcine (Sus scrofa) liver using affinity chromatography
Authors: Canduri Femanda , Ward Richard J. , de Azevedo Walter F. , Gomes Roseli A. S. , Arni R. K. 
Published: July 2007

AbstractCathepsin D, a lysosomal aspartic protease, has been purified from porcine liver using a combination of pepstatin‐A agarose and Affi‐Gel Blue affinity chromatography, followed by size‐exelusion chromatography. The purified protein consists of two polypeptide chains of 15 and 30 kDa, and has an isoelectric point of 6.8. Porcine fiver cathepsin D has maximum activity at pH 2.5‐3.0 as determined by its activity against hemoglobin, with a Kcat of 14.3 s‐1 and a kcat/KM of 2.70×106 s‐1M‐1 as determined by the hydrolysis of a fluorogenic peptide substrate.
Interaction of sodium bis(2‐ethylhexyljt) sulfosuccinate (AOT) with catalase and horseradish peroxidase in an aqueous solution and in the reverse micelles of AOT/n‐heptane
Authors: Gębicka Lidia , Gębicki Jerzy L. 
Published: July 2007

AbstractSome properties of catalase and horseradish peroxidase entrapped into reverse micelles of sodium bis(2‐ethylhexyl) sulfosuccinate (AOT)/n‐heptane with those in an aqueous solution of AOT are compared. Secondary structure of catalase significantly changes and activity is completely lost in the presence of aqueous micellar solution of AOT. In AOT/n‐heptane reverse micelles secondary structure of catalase does not change. AOT has no effect on horseradish peroxidase in aqueous solution. On the other hand slight changes in secondary structure of horseradish peroxidase in AOT/n‐heptane reverse micelles appear. It is concluded that electrostatic interactions between catalase or horseradish peroxidase with AOT molecule at neutral pH are not the main factor determining reactivity of investigated enzymes in reverse micelles.
Effect of seasonal acclimatization on the expresion of the carp transcription factor Pit‐1
Authors: Kausel Gudrun , Vera María Inés , Figueroa Jaime , Hernández Jaime , Martin Rody San , Molina Alfredo , Chavez Viviana Marcela , Muller Marc , Martial Joseph , Krauskopf Manuel 
Published: July 2007

AbstractWe isolated a clone comprising four exons of the carp Pit‐1 gene. Using synthetic oligonucleotide probes derived from the carp Pit‐1 sequence Pit‐1 expression was assessed by in situ hybridization in pituitary sections from summer‐ and winter‐acclimatized carp. Semiquantitative analyses of the hybridization signals revealed a significant higher Pit‐1 expression in the proximal pars distalis (PPD) and pars intermedia (PI) of the pituitary glands from summer‐acclimatized carp, compared to the winter‐acclimatized fish. In both adaptive states, relative to the PPD and PI, only a basal Pit‐1 expression was detected in the rostral pars distalis. Thus, during seasonal acclimatization of an eurythermal fish, Pit‐1 seems to be involved in the mechanisms that underlie the compensatory response.
A human B cell line AF10 expressing hIL‐17
Authors: Zhou Limei , Peng Shanyun , Duan Jubao , Zhou Jing , Wang Lihong , Wang Jiaxi 
Published: July 2007

AbstractAF10, a human B cell line, is a mycoplasma‐free variant cloned from the human IgE myeloma cell line U266. Total RNA isolated from the AF10 cells was used as template for RT‐PCR, and a specific product of about 411bp corresponding to the coding region of hIL‐17 lack of a leading sequence obtained. The sequence of the RT‐PCR product is the same to that reported in the literature. The expressed rhIL‐17 in E. coli can induce 10‐ to 15‐fold increase of IL‐6 secretion by mouse fibroblast 3T3 cells. It is for the first time until now that hIL‐17 messager has been detected in B cell. There may exist some potential relationship between hIL‐17 and myeloma cells.
Hepatic and renal metallothionein induction following single oral administration of gallium arsenide in rats
Authors: Flora Swaran J. S. , Tripathi Neelima 
Published: July 2007

AbstractMetallothionein genes (MT) are inducible by a variety of agents, including heavy metals. We report the induction of MT expression by gallium arsenide (GaAs), a superior intermetallic semiconductor material at two time intervals following single oral exposure in rats. The data is also supplemented with two additional groups exposed to gallium (III) as gallium oxide and arsenic (III) as sodium arsenite to determine which of the two moieties in GaAs is responsible for any such possible effects. The results indicate that GaAs administration does significantly induces MT in hepatic tissues accompanied by an increase in cytosolic glutathione, arsenic, zinc and copper concentration. It thus proves that arsenic moiety is chiefly responsible for such an effect.
Effect of cholesterol/phosholipid ratio on stimulatory GTP‐binding protein function
Authors: Bai Luo , Youguo Huang 
Published: July 2007

AbstractThe effect of different cholesterol/phospholipid (C/P) ratios on the coupling function between stimulatory GTP‐binding protein(Gs) and adenylyl cyclase (AC) in proteoliposomes, and its relationship to the conformational change of Gs were investigated. The results showed that Gs activities of both binding GTPTγS and stimulating adenylyl cyclase were the highest in proteoliposomes with a proper content of cholesterol similar to physiological situation while the lowest with higher cholesterol content similar to pathological situation. In addition, the conformational change of Gs in proteoliposomes was also detected by steady‐state and nanosecond time‐resolved fluorescence using acrylodan as a probe. It is suggested that a proper C/P ratio similar to physiological situation regulates the function of Gs by inducing a change in the physical state of lipid bilayer, which would favor the formation of a suitable conformation of Gs with higher activities of both binding GTP and stimulating adenylyl cyclase. But if C/P ratio is higher, such as in pathological situation, this is unfavorable for motion of Gs in membrane, which results in inhibition of Gs function significantly.