Biomedical subjects

J Gu

Publications and source records attributed to J Gu.

At least 181 records · Page 10Linked to original sources

PubMed1998

[Effect of recombinant human growth hormone on hypoalbuminemia in peritoneal sepsis: experimental and clinical research].

OBJECTIVE: To investigate the effect of recombinant human growth hormone(rhGH) on hypoalbuminemia in peritoneal sepsis. METHODS: We observed rhGH on albumin mRNA expression and albumin sythesis in vitro and in vivo with the method of reverse-transcriptional polymerase chain reaction (RT-PCR). RESULTS: rhGH significantly up-regulated albumin mRNA expression in vitro (143 +/- 6 vs 100.4 +/- 2.2, P < 0.01) and in vivo(152 +/- 8 Vs 100 +/- 3, P < 0.01), and obviously alleviated the inhibition of albumin mRNA expression induced by LPS (P < 0.05). In cecal ligation and puncture-induced septic rats, rhGH significantly raised albumin synthesis(20.4 +/- 1.7 Vs 15.5 +/- 2.9 g/L, P < 0.01) and albumin mRNA expression. In patients with peritoneal sepsis, rhGH in combination with total parenteral nutrition markedly increased serum albumin, prealbumin, and transferrin concentration, but no apparent effect was observed in controls. CONCLUSION: rhGH significantly increases albumin mRNA expression and albumin synthesis in peritoneal sepsis.

Adult↗

PubMed1998

[Expression and purification of recombinant hirudin].

OBJECTIVE: To express the recombinant hirudin variant 1 (rHV1) with biological activity in prokaryotic cells and then isolate and purify the expressed products. METHODS: The hirudin variant 1 gene in plasmid vector pBV220 was expressed in E. coli strain DH5 alpha. The biological activity of rHV1 was determined with chromogenic substrate method. The expressed product was purified by ultrafiltration, DEAE-Sephadex A-50 filtration and thrombin-Sepharose 4B affinity chromatography. RESULTS: The expressed rHV1 accounted for approximately 16.9% of E. coli cell proteins with an activity of 20-30 ATU (antithrombin unit) per milliliter culture. The purified rHV1 showed a homogeneous band on SDS-PAGE. CONCLUSIONS: This is the first report in China on successful expression of hirudin variant 1 gene in E. coli and purification of the expressed rHV1.

Escherichia coli↗

PubMed1998

[Study on the enantiomeric separation of adrenalines by capillary zone electrophoresis].

Capillary zone electrophoresis (CZE) has been used for the enantiomeric separation of the racemic isoprenaline, noradrenaline and adrenaline with bare fused silica capillary and employing beta-cyclodextrin(beta-CD) and beta-cyclodextrin derivatives as the chiral selectors. Both the complexion and enantiomeric resolution were influenced by the temperature, beta-CD type, CD concentration and pH of background electrolyte (BGE). The effects of the BGE types and concentrations on the enantiomeric separation were also investigated. The results showed that 2,6-di-O-carboxymethyl-beta-cyclodextrin (CM-beta-CD) has stronger recognition than that of beta-CD for the chiral separation of the basic drugs under study. The CD concentrations and pH of BGE have strong influence on the efficiency of chiral separation. The adsorption of the basic compound on the surface of bare fused silica capillary is a disadvantage to the chiral separation while the use of beta-CD as the chiral selector and the addition of an amphiphile, such as tetraethylammonium bromide (TEA+) or tetrabutylammonium bromide (TBA+) to the BGE could improve the resolution of the enantiomers due to the reduction of the adsorption of the basic compound on the silica surface by the strong electrostatic force between the positively charged amphiphile and the silica surface. It was also found that as CM-beta-CD was used as the chiral selector there was no influence on the chiral separation of the basic compound whether the amphiphile was added to BGE or not. Lower temperature was favorable to improve the efficiency of the chiral separation. CM-beta-CD gave a baseline enantiomeric separation for isoprenaline, while beta-CD, under the same experimental conditions, gave an incomplete chiral separation. Both CM-beta-CD and beta-CD could not give enantiomeric resolution for noradrenaline and adrenaline.

Electrophoresis, Capillary↗

PubMed1998

[Protective effect of Salvia Miltiorrhizae Composita on myocardium in patients undergoing open heart sugery].

OBJECTIVE: To observe the protective effect of Salvia Miltiorrhizae Composita (SMC) on myocardium injuries induced by oxygen free radicals from ischemic reperfusion in patients undergoing open heart surgery. METHODS: Eighteen patients with either congenital ventricular septal defect (VSD) or atrial septal defect (ASD) were divided randomly into control group and treated group, 9 in each. Patients in the treated group were administered intravenously SMC 200 mg/kg before operation and in rewarming period, while patients of the control group received the same volume of balanced salt solution. Serum malonyldialdehyde (MDA), creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) were measured before operation, 30 min after myocardium ischemia, 30 min after reperfusion, 30 min after cardiopulmonary bypass and 24 hours after operation. RESULTS: Serum MDA, CPK and LDH levels in the treated group at both myocardium ischemic period and ischemic reperfusion period were significantly higher than those at before operation (P < 0.05, P < 0.01). In the treated group, levels of the 3 indexes at myocardium ischemic period increased slightly in comparison with those before operation (P > 0.05), and the levels of them at ischemic reperfusion period were significantly higher than those before operation (P < 0.05), but there was no significant difference between the levels at ischemic reperfusion period and those at 30 min after myocardium ischemia. Comparison between the two groups showed that the serum MDA, CPK and LDH levels were all significantly higher in the control group than those in the control group respectively in all periods (P < 0.01). CONCLUSIONS: SMC could effectively protect myocardium from ischemia and ischemic reperfusion by attenuating the free radical damage and inhibiting lipid peroxidation.

Adolescent↗

PubMed1998

[Effect of recombinant human growth hormone with total parenteral nutrition on albumin synthesis in patients with peritoneal sepsis].

OBJECTIVE: To investigate the effect of recombinant human growth hormone (rhGH) in combination with total parenteral nutrition (TPN) on albumin synthesis in patients with peritoneal sepsis. METHOD: 17 patients with peritoneal sepsis were divided randomly into two groups. The control group received TPN only for 7 days, and the GH group received both rhGH (12 U/d) and TPN for 7 days. The TPN scheme and other treatment were the same in the two groups. RESULT: Serum albumin, prealbumin, and transferrin concentration were increased in patients in the GH group (P < 0.01), but no apparent effect was observed in the control group (P > 0.05). CONCLUSION: In condition of serious peritoneal sepsis, TPN can not increase albumin, prealbumin, and transferrin synthesis alone, whereas rhGH in combination with TPN significantly increase the synthesis of visceral proteins.

Adolescent↗

PubMed1998

[Studies on the crystal structure of ivermectin (H2B1a)].

The crystal structure of ivermectin (H2B1a) was determined by X-ray diffraction. Ivermectin was found to be composed of more than 80% H2B1a and less than 20% H2B1b. The crystal of H2B1a belongs to the space group C2 with a = 40.736(6)A, b = 9.295(3)A, c = 14.966(3)A, beta = 106.93(1) degree. After structure refinement using least-squares method, the final R factor of H2B1a is 0.0658. The space configuration of H2B1a is a long chain along the C-axis. The molecular aggregates are extended into pairs of long chains parallel to each other, some distance apart. The distance between chains is the same, but their direction is opposite. This structure of H2B1a is similar to some biomacromolecules.

Crystallization↗

PubMed1998

[Characterization of some glucuronide conjugates by electrospray ion trap mass spectrometry].

To investigate the characteristics of mass spectra of some drug metabolites, solutions of glucuronide conjugates of N-(4-ethoxyphenyl)-2-hydroxyl-benzamide (etofesalamide), 4-(3H-1, 2-dihydro-1-pyrrolizinone-2-methylamino)-benzoic acid, 5-hydroxypropafenone and propafenone were analyzed using electrospray ion trap mass spectrometry in a multi-stage full scan mode performed on a Finnigan LCQ instrument. Sample solutions were directly introduced into the ESI source at a flow rate of 15-30 microliters.min-1 by a syringe pump. The mass spectrometer was operated in the negative ion mode. A full scan mass spectra of each analyte provided quasimolecular ion m/z M-1, and full scan MS2 and MS3 spectra gave characteristic fragment ions m/z 175 and m/z 113, respectively, which were derived from the glucuronate moiety of each analyte. The proposed interpretation of m/z 175 is the negative ion of glucuronic acid with a loss of 18 u (H2O), which produces m/z 113 after further losing 18 u (H2O) and 44 u (CO2). Fragmentation pathway has been established for each analyte. The results show that quasimolecular ion m/z M-1 and the characteristic fragment ions m/z 175 and m/z 113 in the multi-stage full scan mass analysis of each analyte can be predicted for future structure elucidation or quantitative determination of glucuronide conjugates by LC/MS.

Animals↗

PubMed1998

[An epidemiological survey of schistosome cercarial dermatitis among the residents living along the banks of the Huaihe River system].

AIM: To make an epidemiological survey of schistosome cercarial dermatitis among the residents living along the banks of the Huaihe River. METHODS: Making inquiries about signs and symptoms of schistosome cercarial dermatitis, and physical examinations of manifestation in the residents (fishermen and peasants). Cercariae shed from the Radix auricularia collected in the field were used to infect ducklings. The eggs and miracidia separated from the feces of the full grown ducks bred by fishermen were used to infect Radix auricularia. RESULTS: Schistosome dermatitis locally known as "duck itch" (meaning duck-fecesdermatitis) was discovered among the residents living along the Huaihe River bank. The main signs and symptoms of the dermatitis included diffuse erythema or red papular eruption with areorae, urticae, urticant itch or titillation around the affected areas (including thoracic part, abdomen and lower limbs etc). The cercariae with eye spot were found from Radix auricularia collected from Huaihe riverside and were identified to be the species of Trichobilharzia can both hatch miracidium, which laboratory-reared Radix auricularia were infected with miracidia hatched from the two types of eggs, rhomboid eggs and crescent eggs, found in the feces of full grown ducks bred by fishermen and shed the same cereariae with eye spot. Besides, adult worms of Trichobiharzia were obtained by dissecting both experimentally infected ducklings bred in the laboratory and naturally infected ducks bred in the Huaihe river-side area. The above-mentioned eggs, miracidia, cercariae and adult worms were all identified to belong to the life-phase of Trichobilharzia. CONCLUSION: The epidemic disease known as schistosoma cercarial dermatitis harmful to the health of the residents living along the banks of Huaihe River is caused by the cercariae of Trichobilharzia.

Adult↗

PubMed1998

[Evaluation on the anti-hepatitis C virus enzyme-linked immunosorbent diagnostic kits].

Ten different anti-HCV ELISA kits, four manufactured from abroad (ABBOTT, Innogenetics, Murex, Monolisa) and six in China, were evaluated by China national anti-HCV panel(100 positive, 98 negative) and Boston Biomedical Inc. (BBI) anti-HCV mixted titer performance panel(23 positive and 2 negative). The detective rates in 100 China national anti-HCV positive panel were 98% by ABBOTT EIA 2.0, 96% by BHY, SKH and XWK, 95% by BBS and HHM, 97% by SCJ, and that in 23 BBI anti-HCV positive panel were 100% by ABBOTT EIA2.0, but 91% by Murex, 87% by Innogenetics and Monolisa, 74% by BHY, 87% by SKH, 83% by XWK and HHM, 70% by BBS, 91% by SCJ. The specificity for all negative panels were similar in all kits. According to the results of HCV RIBA test (Ortho HCV RIBA 2.0), the structural antigens contained in all kits were almost the same, but the antigenicity of HCV nonstructural proteins were different, in the kits made in China they were lower than that made from abroad.

Antibodies, Viral↗

PubMed1998

Purification and characterization of heterologously expressed mouse CYP2A5 and CYP2G1: role in metabolic activation of acetaminophen and 2,6-dichlorobenzonitrile in mouse olfactory mucosal microsomes.

The metabolic activation of two known olfactory mucosal (OM) toxicants, acetaminophen (AP) and 2,6-dichlorobenzonitrile (DCBN), was examined with mouse liver and OM microsomes and purified, heterologously expressed mouse CYP2A5 and CYP2G1. In reconstituted systems, both isoforms were active in metabolizing DCBN and AP to metabolites that formed protein adducts. The formation of DCBN- or AP-protein adducts and other AP metabolites, including 3-hydroxy-AP and, in the presence of glutathione, AP-glutathione conjugate, was also detected in OM microsomal reactions and to a much greater extent than in liver microsomes. Evidence was obtained that CYP2A5 and CYP2G1 play major roles in mouse OM microsomal metabolic activation of DCBN and AP. Immunoblot analysis indicated that CYP2A5 and CYP2G1 are abundant P450 isoforms in OM microsomes. OM microsomal AP and DCBN metabolic activation was inhibited by 5- and 8-methoxsalen, which inhibit both CYP2A5 and CYP2G1, and by an inhibitory anti-CYP2A5 antibody that also inhibits CYP2G1. In addition, the roles of CYP1A2 and CYP2E1 in the OM bioactivation of AP and DCBN were ruled out by comparing activities of acetone-treated mice or Cyp1a2(-/-) mice with those of control mice. Thus, CYP2A5 and CYP2G1 may both contribute to the known OM-selective toxicity of AP and DCBN. Further analysis of the kinetics of AP and DCBN metabolism by the purified P450s suggested that CYP2A5 may play a greater role in OM microsomal metabolism of AP, whereas their relative roles in DCBN metabolism may be dose dependent, with CYP2G1 playing more important roles at low substrate concentrations.

Acetaminophen↗

PubMed1998

Mutagen sensitivity as a susceptibility marker for human hepatocellular carcinoma.

Although the pathogenesis of hepatocellular carcinoma (HCC) remains poorly understood, hepatitis B virus and dietary aflatoxin exposures are established etiological factors for this disease. We conducted a pilot study of 28 patients with HCC and 110 healthy controls matched for age, sex, and ethnicity to determine whether constitutional genetic instability, based on the quantification of mutagen-induced chromatid breaks in cultured lymphocytes, modifies an individual's risk of HCC development. The mean numbers of bleomycin-induced breaks per cell for cases and controls were 0.92 and 0.55, respectively (P < 0.0001). For benzo(a)pyrene diol epoxide (BPDE) sensitivity, the values were 0.90 for cases and 0.46 for controls (P < 0.0001). Nearly 68% of the cases but only 27% of the controls exhibited bleomycin sensitivity (i.e., had > or = 0.68 breaks per cell). Eighty % of the case group but only 22% of the control group exhibited BPDE sensitivity (i.e., had > or = 0.58 breaks per cell). On multivariate analyses, both bleomycin sensitivity and BPDE sensitivity were associated with significantly elevated risks for HCC, with odds ratios (95% confidence intervals) of 5.63 (2.30, 13.81) and 14.13 (3.52, 56.68), respectively. For individuals who were sensitive to both assays, the risk was 35.88. A synergistic interaction between the bleomycin sensitivity and BPDE sensitivity in HCC risk was suggested. These preliminary findings suggest that differences in host factors related to the predisposition to chromosome breakage, the capacity for DNA repair, or both may be involved in HCC development by influencing the predisposition of hepatitis B virus integration into human DNA or that the carcinogens induced DNA damage susceptibility. A larger study is needed to confirm these intriguing results.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1998

Differential xenobiotic induction of CYP2A5 in mouse liver, kidney, lung, and olfactory mucosa.

The effects of pyrazole, which is known to induce hepatic cytochrome P4502A5 (CYP2A5) through posttranscriptional mechanisms, on the level of CYP2A5 in liver and extrahepatic tissues were examined in this study. Intraperitoneal administration of pyrazole at 200 mg/kg for 3 days induced CYP2A4/5 mRNAs and proteins and microsomal coumarin 7-hydroxylation activity in liver and kidney of C57BL/6 mice. A marginal increase (30%) in CYP2A4/5 mRNAs was also observed in the olfactory mucosa but not in the lung, and no increase in CYP2A4/5 proteins or microsomal coumarin 7-hydroxylation activity was observed in either the olfactory mucosa or lung. CYP2A4/5 proteins were not detected on immunoblots in other tissues examined, including breast, bone marrow, testis, prostate, ovary, and uterus from control or pyrazole-treated mice. On the other hand, pyrazole treatment induced CYP2E1 in the olfactory mucosa as well as in liver and kidney, indicating that the olfactory mucosa was exposed to pyrazole. The lack of CYP2A inducibility in the olfactory mucosa was also observed for several other known inducers of hepatic CYP2A5, including cobaltous chloride, stannous chloride, griseofulvin, thioacetamide, and aminotriazole. These results suggest that the mechanisms involved in the induction of hepatic and renal CYP2A5 by pyrazole and other xenobiotic compounds may be tissue-specific.

Amitrole↗

PubMed1998

Gamma-ray mutagen sensitivity and survival in patients with glioma.

Despite advances in treatment of brain tumors, cerebral malignant gliomas are rapidly debilitating with poor survival. Patient age and tumor histology are known to influence survival in glioma patients, but these factors do not account for all of the variability in survival time. To identify additional useful predictors, we tested an assay that measures intrinsic gamma-ray mutagen sensitivity. Our hypothesis was that increased sensitivity of peripheral blood lymphocytes to chromatid breaks is associated with tumor aggressiveness and decreased patient survival. The eligible 76 patients were those with histologically confirmed malignant gliomas, seen at the University of Texas M. D. Anderson Cancer Center between 1994 and 1997, for whom we had sufficient blood for the in vitro gamma-radiation assay. After gamma-irradiation of each subject's lymphocytes, the frank chromatid breaks in 50 metaphases were averaged to calculate breaks/cell. On the basis of our patient series, we established a gamma-ray mutagen sensitivity cutoff point of 0.55 breaks/cell that was confirmed by bootstrap resampling techniques. Patients with values >0.55 breaks/cell were considered sensitive. Kaplan-Meier and Cox proportional hazards modeling were used for the analysis. The gamma-ray mutagen-sensitive patients had worse survival than the nonsensitive patients, with an unadjusted hazard rate ratio of 1.6 (95% confidence interval, 0.9-2.8; P = 0.15). After adjustment for age, tumor histology, and extent of surgical resection, the hazard rate ratio was 2.4 (95% confidence interval, 1.3-4.6; P = 0.0081). Our data suggest that gamma-ray mutagen sensitivity is a prognostic indicator of survival in glioma patients. The significance of these findings needs to be verified in studies with larger samples of patients with histologically similar gliomas.

Adult↗

PubMed1997

Characterization of the structure and function of the fourth member of p38 group mitogen-activated protein kinases, p38delta.

We have cloned and characterized a new member of the p38 group of mitogen-activated protein kinases here termed p38delta. Sequence comparisons revealed that p38delta is approximately 60% identical to the other three p38 isoforms but only 40-45% to the other mitogen-activated protein kinase family members. It contains the TGY dual phosphorylation site present in all p38 group members and is activated by a group of extracellular stimuli including cytokines and environmental stresses that also activate the other three known p38 isoforms. However, unlike the other p38 isoforms, the kinase activity of p38delta is not blocked by the pyridinyl imidazole, 4-(4-fluorophenyl)-2-2(4-hydroxyphenyl)-5-(4-pyridyl)-imidazole (identicalto SB202190). p38delta can be activated by MKK3 and MKK6, known activators of the other isoforms. Nonetheless, in-gel kinase assays provide evidence for additional activators. The data presented herein show that p38delta has many properties that are similar to those of other p38 group members. Nonetheless important differences exist among the four members of the p38 group of enzymes, and thus each may have highly specific, individual contributions to biologic events involving activation of the p38 pathways.

Amino Acid Sequence↗

PubMed1997

Formation of 2',3'-cyclic phosphates at the 3' end of human U6 small nuclear RNA in vitro. Identification of 2',3'-cyclic phosphates at the 3' ends of human signal recognition particle and mitochondrial RNA processing RNAs.

Approximately 90% of human U6 small nuclear RNA (snRNA) contains uridine cyclic phosphate (U>p) at its 3'-end (Lund, E., and Dahlberg, J. E. (1992) Science 255, 327-330). We studied the formation of U>p at the 3' end of human U6 snRNA using an in vitro system where uridylic acid residues are added from UTP precursor and U>p is formed. Analysis of U6 snRNAs with varying number of uridylic acid residues showed that each of these species contains U>p where the phosphate originated from alpha-phosphate of UTP precursor. The cyclic phosphate formation occurred on U6 snRNA in extracts where essential spliceosomal snRNAs were specifically degraded, thereby indicating that U>p formation is not coupled to pre-mRNA splicing. A subpopulation of human signal recognition particle and mitochondrial RNA processing RNAs isolated from HeLa cells also contained cyclic phosphates at their 3' ends. These data suggest that U>p in U6 snRNA is unlikely to be related to its participation in splicing of pre-mRNAs. It appears that cyclic phosphate is an intermediate product in the metabolism of these small RNAs.

HeLa Cells↗

PubMed1997

Niemann-Pick C1 disease gene: homology to mediators of cholesterol homeostasis.

Niemann-Pick type C (NP-C) disease, a fatal neurovisceral disorder, is characterized by lysosomal accumulation of low density lipoprotein (LDL)-derived cholesterol. By positional cloning methods, a gene (NPC1) with insertion, deletion, and missense mutations has been identified in NP-C patients. Transfection of NP-C fibroblasts with wild-type NPC1 cDNA resulted in correction of their excessive lysosomal storage of LDL cholesterol, thereby defining the critical role of NPC1 in regulation of intracellular cholesterol trafficking. The 1278-amino acid NPC1 protein has sequence similarity to the morphogen receptor PATCHED and the putative sterol-sensing regions of SREBP cleavage-activating protein (SCAP) and 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase.

Amino Acid Sequence↗

PubMed1997

Effects of epidermal growth factor and insulin on the activity of N-acetylglucosaminyltransferase V.

When quiescent rat hepatocellular carcinoma 7919 cells were treated with epidermal growth factor (EGF) or insulin (stimulators of receptor tyrosine kinase activity), the activity of N-acetylglucosaminyltransferase V was increased. The effect of EGF reached a maximum after 10 min and remained high for 30 min, while the effect of insulin reached a maximum after 5 min and decreased after 15 min. Preincubation of the cells with 1-O-octadecyl-2-O-methylglycerophosphocholine (Et18-OH3), which blocked the activation of mitogen-activated protein kinase by EGF, also blocked the activation of N-acetylglucosamyltransferase V by this hormone, whereas the activation of N-acetylglucosamyltransferase V by insulin could not be blocked by Et18-OH3. Our results suggest that N-acetylglucosamyltransferase V may be regulated by different receptor protein tyrosine kinase pathways.

Animals↗

PubMed1997

A patient with type 2N von Willebrand disease is heterozygous for a new mutation: Gly22Glu. Demonstration of a defective expression of the second allele by the use of monoclonal antibodies.

We report the case of a Chinese patient who has subnormal von Willebrand factor (vWF) level and normal vWF multimeric pattern, but a lack of vWF capacity to bind factor VIII (FVIII). Exons 18 to 20 of the patient's vWF gene were analyzed by DGGE and a G2354 --> A substitution which changes the encoded amino acid sequence from Gly22 to Glu was identified. The patient is heterozygous for this substitution, creating a unique Sac I restriction site. Recombinant vWF (rvWF) containing the candidate mutation was transiently expressed in COS-7 cells. It was processed and secreted normally but failed to bind FVIII. FVIII binding ability of hybrid rvWF, obtained by cotransfection of normal and mutated expression vectors and corresponding to a heterozygous genotype, was moderately decreased. To explain this functional discrepancy between patient's plasma vWF and hybrid rvWF, we used anti-vWF monoclonal antibodies (MoAbs) as capture in an enzyme-linked immunosorbent assay test. MoAb 32B12 recognized both wild-type and mutated rvWFs whereas MoAb 418 did not recognize mutated rvWF. Because MoAb 418 also failed to capture the plasma vWF from propositus, it means that his second nonmutated allele is not expressed or expressed at a very low level.

Adult↗