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Biomedical subjects

He Zhang

Publications and source records attributed to He Zhang.

30 records · Page 2Linked to original sources
PubMed2005

Identification of cry-type genes on 20-kb DNA associated with Cry1 crystal proteins from Bacillus thuringiensis.

Heterologous DNA fragments (20-kb) associated with Cry1 crystal proteins (protoxins) from a soil-isolated Bacillus thuringiensis strain 4.0718 were isolated and analyzed. RFLP patterns of the PCR products showed that the 20-kb DNA fragments harbored cry1Aa, cry1Ac, cry2Aa, and cry2Ab genes. Furthermore, a 4.2-kb DNA fragment, which contained the promoter, the coding region, and the terminator of cry1Ac gene, was cloned from the 20-kb DNAs by PCR, and then the cry1Ac gene was expressed in an acrystalliferous B. thuringiensis strain 4Q7 by using E. coli-B. thuringiensis shuttle vector pHT3101. SDS-PAGE and microscopy studies revealed that the recombinant could express 130-kDa Cry1Ac protoxin and produce bipyramidal crystals during sporulation. Bioassay results proved that crystal-spore mixture from the recombinant was toxic to Plutella xylostella. This was the first report of cry-type genes present on 20-kb DNA associated with Cry1 protoxins of B. thuringiensis.

Bacillus thuringiensis↗
PubMed2005

[An investigation of the sexual physiological and psychological development of 2,770 high school students in Yibin].

OBJECTIVE: To investigate the actual condition of the sexual physiological and psychological development of the high school students in Yibin in order to get a reliable basis for sexual education of the teenagers. METHODS: With a proportion of 1% to the whole, 2,770 students were randomly selected from eight high schools in the urban and rural areas of the city. We devised a questionnaire and asked each student to fill in his or her answers presently. RESULTS: So far as sexual physiological and psychological development was concerned, the high school students of Yibin were found rather precocious, with very little sexual knowledge and psychological endurance in sexual affairs and a relative lack of sexual education. CONCLUSION: It is imperative to extend the scope of puberty sexual education in high schools. Teenagers must be taught different kinds of sexual knowledge at different periods of growth as well as how to avoid sexually transmitted diseases and gestation. The sexual knowledge level of the teachers must also be raised. It is a must to establish service or specialist consultation hot lines about sexual knowledge for teenagers. Parents are expected to change their traditional views and assume an active role in the joint efforts of sexual education for their children.

Adolescent↗
PubMed2004

A luminescent chemosensor with specific response for Mg2+.

A novel chemosensor, a cyclometalated platinum(II) bipyridyl acetylide complex containing a monoazacrown moiety in the acetylide ligand, which can signal Mg(2+) specifically and display large changes both in color and in luminescence intensity upon complexation with Mg(2+), is described.

Journal Article↗
PubMed2004

Unusual mesoporous SBA-15 with parallel channels running along the short axis.

Submicrometer-sized mesoporous silica SBA-15 with cuboidlike morphology has been prepared by using excess amounts of decane as cosolvent in the presence of NH4F. The channels of the resulting material run parallel to the short axis of the cuboid-like SBA-15. It has also been found that the materials have a well-ordered channel structure with pore size ca. 12 nm.

Journal Article↗
PubMed2004

Evaluation of the viability and energy metabolism of canine pancreas graft subjected to significant warm ischemia damage during preservation by UW solution cold storage method.

AIM: To evaluate the viability and energy metabolism of long warm ischemically damaged pancreas during preservation by the UW solution cold storage method. METHODS: The pancreas grafts subjected to 30-120 min warm ischemia were preserved by the UW solution cold storage method for 24 h. The tissue concentrations of adenine nucleotides (AN) and adenosine triphosphate (ATP) and total adenine nucleotides (TAN) were determined by using high performance liquid chromatography (HPLC) and the viability of the pancreas graft was tested in the canine model of segmental pancreas autotransplantation. RESULTS: The functional success rates of pancreas grafts of groups after 30 min, 60 min, 90 min, 120 min of warm ischemia were 100%, 100%, 67.7%, 0%, respectively. There was an excellent correlation between the posttransplant viability and tissue concentration of ATP and TAN at the end of preservation. CONCLUSION: The UW solution cold storage method was effective for functional recovery of the pancreas suffering 60-min warm ischemia. The tissue concentration of ATP and TAN at the end of 24 h preservation by the UW solution cold storage method would predict the posttransplant outcome of pancreas graft subjected to significant warm ischemia.

Adenosine↗
PubMed2004

Aetiology of epilepsy in surgically treated patients in China.

The aim of this retrospective, multicenter clinical study was to evaluate the aetiology of epilepsy in surgically treated patients in China. The detailed clinical records of all intractable partial epilepsy (IPE) were reviewed in five tertiary referral centres from June 1991 to June 2000. 1650 patients (927 males, 723 females) were recruited. 41.4% had aetiological factors, including the histories of major brain trauma (20.9%), febrile seizure (6.5%), meningitis (5.4%), encephalitis (5.0%), prenatal distress (2.1%), birth trauma (0.8%) and family history of seizure (0.7%). The pathological lesions were divided into eight groups according to the nature of the lesion: scar (19.2%), vascular malformations (VM) (17.7%), hippocampal sclerosis (HS) (16.2%), tumours (15.0%), gliosis (12.1%), neuronal migration disorders (NMDs) (7.4%), intracranial infection (4.5%), and other lesions (7.9%). In conclusion, effective management of these aetiological factors and pathological lesions may be essential to deal with IPE. Scar, HS, VM, NMDs are the most likely consequences of antecedent morbid events.

Brain Neoplasms↗
PubMed2004

The pregnane X receptor binds to response elements in a genomic context-dependent manner, and PXR activator rifampicin selectively alters the binding among target genes.

The pregnane X receptor (PXR) is a key regulator of genes encoding several major types of cytochrome P450 enzymes and transporters (e.g., multidrug resistance-1, MDR1); therefore, PXR contributes significantly to drug-drug interactions. PXR binds to response elements and confers transactivation. Several target genes such as CYP3A4 and 3A7 contain two PXR elements (distant and proximal) that are separated by more than 7000 nucleotides in the genome. Disruption of the distant element causes a 73% decrease of the reporter activity, whereas inactivation of the proximal element decreases by only 53%. This study was undertaken to test the hypothesis that PXR differentially binds to the elements with the distant enhancer being bound to a higher extent. To test this hypothesis, a stable transfected line (hPXR-HRE) was prepared to constitutively express human PXR and harbor a chromatinized CYP3A4-ER6 reporter. This line responded to rifampicin and dexamethasone similarly as hepatocytes based on the relative potency and activation kinetics. Contrary to the hypothesis, chromatin immunoprecipitation experiments showed that the genomic fragment harboring the proximal element was preferably precipitated over the fragment containing the distant element in the CYP3A4 gene, but the opposite was true with the CYP3A7 gene. In addition, the promoters from the MDR1 and CYP2B6 genes were abundantly present in the PXR immunocomplexes from the vehicle-treated cells. However, such abundant interactions were markedly diminished when cells were treated with PXR activator rifampicin. These findings suggest that PXR binding is dependent on the genomic context and PXR activators modulate such bindings.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

The environmental pollutant 1,1-dichloro-2,2-bis (p-chlorophenyl)ethylene induces rat hepatic cytochrome P450 2B and 3A expression through the constitutive androstane receptor and pregnane X receptor.

1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a persistent environmental contaminant, is a metabolite of the pesticide 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT). DDE is similar to phenobarbital (PB) in that both compounds are inducers of rat hepatic cytochrome P450 2B and 3A (CYP 2B and 3A). The induction of CYP 2B and 3A by PB is known to be regulated through the nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR), respectively. In the current study, the induction of hepatic CYP 3A1 and 2B1 by DDE was correlated with CAR and PXR activity. Induction of 3A1 and 2B1 was observed in the livers of adult and developing male Sprague-Dawley rats following exposure to DDE. Increased hepatic expression of 3A1, but not 2B1, in developing rats exposed during gestation and lactation persisted into adulthood. In receptor transactivation assays, both CAR and PXR transcriptional activities were significantly enhanced by DDE. Nuclear accumulation of CAR, but not PXR, was observed in the liver tissue following DDE and PB treatment. These data support the idea that induction of hepatic 3A1 and 2B1 by DDE is mediated through the activation of CAR and PXR. This study suggests that regulation by environmental compounds of hepatic enzymes via CAR and PXR may have impact on the metabolism of endogenous and exogenous substrates.

Animals↗
PubMed2002

Abundant expression of Dec1/stra13/sharp2 in colon carcinoma: its antagonizing role in serum deprivation-induced apoptosis and selective inhibition of procaspase activation.

The basic helix-loop-helix (bHLH) proteins are intimately associated with developmental events such as cell differentiation and lineage commitment. The HLH domain in the bHLH motif is responsible for dimerization, whereas the basic region mediates DNA binding. Based on sequence alignment and domain analysis, differentially expressed in chondrocytes/stimulated with retinoic acid/split and hairy-related proteins (DEC/STRA/SHARPs) represent a new class of bHLH proteins. The present study describes the functional characterization of DEC1. Subtractive experiments and blotting analyses demonstrated that DEC1 was highly expressed in colon carcinomas, but not in the adjacent normal tissues. Several cell cycle blockers markedly induced DEC1 expression. Stable transfectants with a tetracycline-inducible construct demonstrated that DEC1 caused proliferation inhibition, antagonized serum deprivation-induced apoptosis and selectively inhibited the activation of procaspases. These activities were highly correlated with the abundance of tetracycline-induced DEC1. Stable transfectants expressing a mutant DEC1 (lacking the DNA-binding domain) exhibited neither proliferation inhibition nor apoptotic antagonism, which suggests that DNA binding is required for these actions. Enzymic assays and immunoblotting analyses demonstrated that induction of DEC1 by tetracycline significantly decreased the activation of procaspases 3, 7 and 9 but not procaspase 8. The selective suppression on the activation of procaspases 3, 7 and 9 over procaspase 8 suggests that DEC1-mediated anti-apoptosis is achieved by blocking apoptotic pathways initiated via the mitochondria. The results functionally distinguish DEC1 from other bHLH proteins and directly link this factor to oncogenesis.

Adenocarcinoma↗
PubMed2002

Effect of human serum albumin on cell attachment of human gingival epithelial cells.

OBJECTIVE: To investigate the effect of human serum albumin (HSA) on cell attachment of human gingival epithelial cells (HGE). METHODS: HGE were primary cultured with keratinocyte serum-free medium (KSFM) and dispase. The cultured cells were immunohistochemically stained by monoclonal anti-pan cytokeratin. MTT test was employed to investigate the influence of HSA on the cell attachment on polystyrene surface. The cell growth curve of HGE which were cultured in KSFM with 50 g/L HSA was observed. RESULTS: The results showed significant decrease in cell numbers within 8 hours after HGE were inoculated, in which the polystyrene surface was preincubated with 50 g/L HSA. But it did not prove to be the case from 10 hours to 24 hours after HGE were inoculated. There were no significant difference within 24 hours in cell numbers between cultured in KSFM with 50 g/L HSA and control. The cell numbers in cell growth curve of HGE in KSFM with and without 50 g/L HSA did not show significant difference. CONCLUSIONS: HSA preincubation on polystyrene were produce inhibitory effect of HGE attachment in early stage.

Cell Adhesion↗
PubMedDate not supplied

Cerebral infarction due to giant cell arteritis-three case reports.

The objective of this report was to explore the clinical features of patients with cerebral infarction due to giant cell (temporal) arteritis (GCA) and its characteristic changes in pathology, and on computed tomography (CT) and magnetic resonance imaging (MRI). Three cases of cerebral infarction due to GCA, treated during the past 2 years, were analyzed. Their clinical manifestations were observed carefully, their temporal artery biopsies were performed, their immunohistochemistries were done, and CT as well as MRI were used. The results showed that all the patients had new-onset headache and temporal artery abnormality when the disease began, and there was tremor on the right limbs of 1 patient; temporal artery biopsies revealed evidence of inflammatory cell infiltration in the arterial wall, mainly including T-lymphocytes and macrophages; small cerebral infarction foci were found on CT and MRI; and the responses to corticosteroid therapies were good. The results suggest that it is important to recognize the clinical features of cerebral infarction due to GCA, including the changes of pathology and on CT and MRI. In some cases, special attention is paid to differentiating between atherosclerotic infarction and infections to avoid misdiagnosis.

Aged↗