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Biomedical subjects

C Zhu

Publications and source records attributed to C Zhu.

At least 163 records · Page 9Linked to original sources
PubMed1997

Interaction of ATF6 and serum response factor.

Serum response factor (SRF) is a transcription factor which binds to the serum response element (SRE) in the c-fos promoter. It is required for regulated expression of the c-fos gene as well as other immediate-early genes and some tissue-specific genes. To better understand the regulation of SRF, we used a yeast interaction assay to screen a human HeLa cell cDNA library for SRF-interacting proteins. ATF6, a basic-leucine zipper protein, was isolated by binding to SRF and in particular to its transcriptional activation domain. The binding of ATF6 to SRF was also detected in vitro. An ATF6-VP16 chimera activated expression of an SRE reporter gene in HeLa cells, suggesting that ATF6 can interact with endogenous SRF. More strikingly, an antisense ATF6 construct reduced serum induction of a c-fos reporter gene, suggesting that ATF6 is involved in activation of transcription by SRF. ATF6 was previously partially cloned as a member of the ATF family. The complete cDNA of ATF6 was isolated, and its expression pattern was described.

Activating Transcription Factor 6↗
PubMed1997

Pain control in recovering alcoholics: effects of local anesthesia.

OBJECTIVE: The medical literature suggests that alcoholics may present greater challenges to achieving clinical pain control than nonalcoholics. This study was undertaken to test the hypotheses that: (1) significant differences exist between alcoholics and nonalcoholics on detection and pain thresholds during electric tooth stimulation; (2) group differences exist in the depth and time course of pulpal anesthesia; and (3) responses to tooth stimulation are associated with severity of alcoholism and/or other psychological factors. METHOD: Male alcoholics (n = 22) in aftercare treatment (mean length of sobriety = 113 days) and age-matched nonalcoholics (n = 22) received 1.0 ml of 3% mepivicaine at the apex of a maxillary lateral incisor and saline placebo at the apex of the contralateral incisor. RESULTS: At baseline no group differences were found on sensory thresholds. During drug intervention significant drug and time effects for both detection threshold (p < .0001) and pain threshold (p < .0001) were found, but group differences and interactive effects were not significant. By exploratory regression analysis of alcoholic subjects, history of depression/unhappiness was significantly associated with shallower pulpal anesthesia, whereas high need for control/low actual control and frequency of treatment for detoxification were associated with deeper anesthesia. CONCLUSIONS: Our findings suggest alcoholics in recovery are not at increased risk for inadequate pain control with local anesthesia.

Adult↗
PubMed1997

[Alterations of substance P-immune reaction positive neurons of cerebral tissues in epileptic rats].

Employing the immunocytochemical analysis, we observed the alterations of Substance P-Immune Reaction (SP-IR) positive neurons of the cerebral cortex, hippocampus and amygdala in rats suffering from epilepsy induced by Penicillin (PEN). The result showed that the number of neurons of epileptic group was higher than that of the control group and no significant change in the rumber of neurons was observed in the group in which PEN was given after injection of Nimodine. It indicates that SP and Ca2+ participate in the process of epileptogenesis.

Amygdala↗
PubMed1997

[Anti-virus effect of hepatocyte stimulating substance (HSS) on duck hepatitis B virus in vivo].

We used one day old Beijing ducklings infected by duck hepatitis B virus as experimental model to observe anti-virus effect of HSS. Beijing ducklings hatched within one day were injected intravenously with duck hepatitis B virus (DHBV). Positive DHBV-DNA in ducklings' sera were detected 7 days later. Serum samples were obtained from all ducklings before, during and after drug treatment at different times and stored at -70 degrees C. The collected samples were detected DHBV-DNA by dot-blot hybridization test at the same time. The therapeutic effects were evaluated by OD value of dot-blot and by the inhibitory rate of DHBV-DNA. The results showed that HSS (with 50 mg/kg/day and 200 mg/kg/day) were effective in inhibition of DHBV-DNA during and after drug treatment, especially in the HSS group of large dosage. The inhibitory effect appeared early and high dynamic. The inhibitory rate of DHBV-DNA during and after drug treatment were higher than the NS group (P < 0.05). No inhibitory effect was observed in NS group. The hepatic biopsy showed HSS groups had milder damage than NS group, indicating that the HSS could inhibit the replication of DHBV-DNA in Beijing ducklings.

Animals↗
PubMed1997

[The contents of plasma norepinephrine and epinephrine in patients with five types of Gan syndromes in TCM and its significance for diagnosis].

Plasma norepinephrine (NE) epinephrine (E) concentrations in patients with five types of Gan syndromes and relative syndromes were determined. The healthy individuals served as control. The contents of NE and E in Ganyang Huafeng Zheng (5975.8 +/- 305.6 pmol.L-1, 2227.7 +/- 12.57 pmol.L-1) were significantly increased; Ganxue Xu Zheng (1100.4 +/- 105.5, 451.2 +/- 70.9 pmol.L-1) were decreased, and lower than the normal controls. NE and E contents in both Ganyang Shangkang Zheng (3962.6 +/- 354.4, 1225.6 +/- 163.5 pmol.L-1) and Ganhuo Shangyan Zheng (3398.1 +/- 303.8, 1134.4 +/- 146.9 pmol.L-1) were increased remarkably, but there was no difference between them. Plasma NE, E concentrations can be considered as one of the comprehensive laboratory parameters in diagnosis of the four above mentioned Gan syndromes.

Adolescent↗
PubMed1996

Ku86-deficient mice exhibit severe combined immunodeficiency and defective processing of V(D)J recombination intermediates.

Ku is a heterodimeric DNA end binding complex composed of 70 and 86 kDa subunits. Here, we show that Ku86 is essential for normal V(D)J recombination in vivo, as Ku86-deficient mice are severely defective for formation of coding joints. Unlike severe combined immunodeficient (scid) mice, Ku86-deficient mice are also defective for signal joint formation. Both hairpin coding ends and blunt full-length signal ends accumulate. Contrary to expectation, Ku86 is evidently not required for protection of either type of V(D)J recombination intermediate. Instead, V(D)J recombination appears to be arrested after the cleavage step in Ku86-deficient mice. We suggest that Ku86 may be required to remodel or disassemble DNA-protein complexes containing broken ends, making them available for further processing and joining.

Animals↗
PubMed1996

p53 is required for both radiation-induced differentiation and rescue of V(D)J rearrangement in scid mouse thymocytes.

The murine scid mutation affects both V(D)J recombination and DNA repair. This mutation has been mapped to the gene encoding the catalytic subunit of the DNA-dependent protein kinase (DNA-PK), which is activated by DNA damage in normal cells. In scid mice, antigen receptor gene rearrangements are initiated normally, but impaired joining of coding ends prevents assembly of functional receptor genes, resulting in arrest of B- and T-cell development. Others have shown that exposure of scid mice to genotoxic agents such as gamma-irradiation rescues rearrangement at the T-cell receptor (TCR) beta locus and promotes thymocyte development. Here we demonstrate that irradiation rescues rearrangements at multiple TCR loci, suggesting a general effect on the recombination mechanism. Furthermore, our data show that p53 is required for irradiation-mediated rescue of both thymocyte development and V(D)J recombination. We also find that thymocyte proliferation and differentiation in the absence of DNA damage do not require p53 and are not sufficient to rescue V(D)J recombination. These results suggest that exposure to ionizing radiation facilitates a partial bypass of the scid defect, perhaps by inducing p53-dependent DNA damage response pathways.

Animals↗
PubMed1996

Thymocyte differentiation in gamma-irradiated severe-combined immunodeficient mice: characterization of intermediates and products of V(D)J recombination at the T cell receptor alpha locus.

Treatment with DNA-damaging agents promotes rescue of V(D)J recombination, limited thymocyte differentiation, and development of thymic lymphomas in severe-combined immunodeficient (SCID) mice. One intriguing aspect of this system is that irradiation rescues rearrangements at the T cell receptor (TCR) beta, gamma and delta loci, but not at the TCR alpha locus. Current models posit that only those loci that are recombinationally active at the time of irradiation can be rescued. Here, we employ sensitive, semiquantitative ligation-mediated polymerase chain reaction assays to detect a specific class of recombination intermediates, hairpin coding ends, at the TCR alpha locus. We found that J alpha-coding ends are undetectable in unirradiated SCID thymocytes, but accumulate after irradiation at times coincident with the emergence of a CD4+ CD8+ thymocyte population. Coding joints produced by joining of these ends, however, are extremely rare. To test whether the presence of hairpin coding ends at TCR alpha is sufficient for irradiation-mediated rescue of coding joint formation, we administered a second dose of gamma-irradiation after abundant CD4+ CD8+ thymocytes and hairpin TCR alpha coding ends had accumulated. This treatment failed to stimulate rescue of TCR alpha coding joints. Thus, the presence of hairpin coding ends at the time of irradiation, while perhaps necessary, is not sufficient for rescue of V(D)J rearrangements. These results support a refined model for irradiation-mediated rescue of TCR rearrangements in SCID mice.

Animals↗
PubMed1996

Detection and localization of the EaeA protein of attaching and effacing Escherichia coli O45 from pigs using a monoclonal antibody.

The eaeA-positive, attaching and effacing (A/E) O45 E. coli isolates from pigs express an EaeA protein with an estimated molecular weight of 97 kDa. In the present study, a monoclonal antibody was raised against the EaeA protein of an A/E O45 isolate. Cross reaction of the monoclonal antibody with the EaeA protein of A/E strain of the rabbit (RDEC-1), but not with those of A/E strains of the human (E2348/69) and dog (89-4221), was observed. Reactions of the monoclonal antibody to A/E isolates in the O45 serogroup on the ELISA varied among isolates and appeared to be correlated with in vivo A/E capacity of these isolates. The EaeA protein of A/E O45 E. coli has an apparent isoelectric point of 8.4 and is exposed on the bacterial surface. The monoclonal antibody provides a useful tool for characterization of the EaeA protein of E. coli isolates from pigs.

Adhesins, Bacterial↗
PubMed1996

Psychological long-term effects of sterilization on anxiety and depression.

Two-thousand cases (500 women and 500 men with sterilization; 500 women and 500 men without sterilization) in two counties and two cities in Sichuan, China, were investigated between 15 September 1992 and 30 April 1993. Information was obtained about their age, parity, marriage, contraceptives, social behavior, and present psychological characteristics. CES-D, SAS, and E.P.Q. scales were used to assess the depressive symptomatology, anxiety, and personality of the subjects. The results revealed that sterilization psychologically affected the depressive symptoms and anxiety under the neutral personality. In addition, depressive symptoms and anxiety were related to the subjects' age, educational level, income, operative doctors' attitudes to sterilization acceptors, and subjects' understanding of the sterilization.

Adult↗
PubMed1996

Genotypic and phenotypic characterization of Escherichia coli isolates from dogs manifesting attaching and effacing lesions.

Thirteen Escherichia coli isolates from dogs manifesting attaching and effacing lesions were characterized genetically with respect to the presence of the following virulence determinants associated with human enteropathogenic E. coli (EPEC): eaeA, encoding the outer membrane protein intimin; eaeB, which is necessary for inducing signal transduction; bfpA, encoding the bundle-forming pilus; and the EAF (stands for EPEC adherence factor) plasmid. These isolates were also analyzed phenotypically with respect to adherence to mammalian cells in vivo and in vitro. Nine of these 13 isolates were found to be eaeA positive by PCR: four of these nine were eaeB positive. The 5' end, but not the 3' end, of the eaeA gene was amplified by PCR when primers derived from the eaeA gene of EPEC were used. Six and eight of these 13 isolates were found to be bfpA positive and EAF positive, respectively. The bfpA gene and EAF locus were found on high-molecular-weight plasmids, whereas the eaeA and eaeB genes were chromosomally located when present. Only one canine E. coli isolate, 4221, which was positive for eaeA, eaeB, bfpA, and EAF, adhered to HEp-2 cells in a localized manner and was positive in the fluorescence actin staining test. The nine eaeA-positive isolates adhered to the mucosal surface of piglet ileal explants and induced some microvillus effacement. However, when tested in experimentally inoculated gnotobiotic piglets, isolate 4221 did not induce attaching and effacing lesions at any level of the intestinal tract. Our results indicate that canine E. coli isolates associated with attaching and effacing lesions share some properties with human EPEC but form a heterogeneous group.

Animals↗
PubMed1996

Kashin-Beck disease: radiographic appearance in the hands and wrists.

PURPOSE: To review the radiographic changes of Kashin-Beck disease (KBD) in the hands and wrists and provide a method for the diagnosis, staging, and evaluation of the effectiveness of prevention and treatment of this disease. To perform radiographic-histologic correlation to facilitate an early diagnosis of KBD. MATERIALS AND METHODS: Hand and wrist radiographs in 300 children and five autopsy cases with KBD from an endemic area of China were analyzed for radiographic changes in the epiphyseal plates, bone ends, epiphyses, and carpal bones. Histopathologic sections of the hand and wrist from five autopsies were studied for comparison with corresponding radiographs. RESULTS: The chief histopathologic changes in KBD included chondronecrosis, secondary repair, and remodeling processes. These histopathologic stages occurred in isolation or simultaneously in a patient. The radiographic and histopathologic changes within cartilage were related specifically to the different sites of cartilage. CONCLUSION: Radiographic changes in the hands and wrists in patients with KBD result from atrophy and necrosis of chondrocytes and their subsequent repair processes in the deep layer of growing cartilage.

Carpal Bones↗
PubMed1996

The estimation of caries prevalence in small areas.

National surveys have been effective for the estimation of caries prevalence in broad regions of the US. However, it is unclear if data from such surveys can be used to estimate prevalences in small areas such as states or counties because of small sample sizes within individual areas. In this study, we applied specialized statistical methods to the estimation of small-area caries measures using data from an oral health survey conducted in the State of Washington. Dental exams to assess caries and the presence of sealants and fluorosis were performed on 2921 third-grade students in 84 public schools selected by a stratified random sample from all 39 counties in the state. Statistical methods for small-area estimation were used to estimate disease and sealant utilization measures for each of the counties. Adjustment was made for covariates measured at the school level, including ethnicity and the proportion of children in the Federally sponsored school lunch program. Substantial variability in disease and sealant utilization between counties was found. The estimated number of decayed and filled surfaces per child was 4.7 (inter-county range, 2.4 to 7.4). The estimated number of surfaces of untreated decay was 1.2 per child overall (range, 0.5 to 3.1). Thirty percent of the children had restorative treatment needs (range, 15 to 54%). The prevalence of sealants on one or more permanent molars was estimated to be 34% (range, 19 to 46%). Overall, only 8% of children showed evidence of fluorosis. The results demonstrate the usefulness of small-area estimation methods for oral health surveys.

Child↗
PubMed1996

[Tau protein in cerebrospinal fluid--a potential marker of Alzheimer's disease].

Levels of the microtubule-associated protein tau in cerebrospinal fluid (CSF-tau) were measured in samples from 87 patients with Alzheimer's disease (AD), 114 patients with non-AD neurological diseases, and 22 normal control subjects, by sandwich enzyme-linked immunosorbent assay. The CSF-tau level was significantly higher in patients with AD than in patients with non-AD neurological diseases and in controls. High CSF-tau levels were found irrespective of age at onset, apolipoprotein E genotype, clinical stage, and ethnic group. Western blots of AD CSF proteins revealed two to three immunoreactive bands with apparent molecular mass between 50 and 65 kDa, which is consistent with phosphorylated CSF-tau. These results suggest that CSF-tau reflects progressive accumulation of tau due to the progressive death of neurons in the AD brain. Assay of CSF-tau may prove to be a reliable diagnostic test for AD.

Aged↗
PubMed1996

Mechanism of V(D)J recombination.

THe V(D)J recombination reaction can be separated into two fundamental operations: site specific cleavage and joining of broken ends. Much has been learned about the mechanisms of these steps in the past few years. Recent experiments have shown that cleavage is catalyzed by the RAG1 and RAG2 proteins and generates an asymmetric set of broken ends: hairpin coding ends and blunt signal ends. A cell free system capable of performing cleavages has been established, and detailed biochemical information about the reaction should accumulate rapidly. In vivo studies have provided insights into the regulation of cleavage. Recent experiments using artificial recombination substrates in cultured cells have shown that efficient cleavage requires a pair of RSS, one with a 12 nucleotide spacer and one with a 23 nucleotide spacer. Our understanding of the joining mechanism has also increased substantially, as several proteins involved in coding joint and signal joint formation (as well as in DSB repair) were recently identified.

Animals↗