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Biomedical subjects

J Zhou

Publications and source records attributed to J Zhou.

At least 487 records · Page 27Linked to original sources
PubMed1999

[Construction of a GFP broad-host-range promoter-probe vector and its application].

The 0.9 kb DNA fragment was obtained by PCR and using a pair of special designed primers from the green fluorescent protein gene(gfp). It Was then cloned into an expression vector pET-11C and named as pHN115. A promoferless gfp vector with SD fragment was obtained from pHN115 and subcloned into SK(+), pIJ 2925 and finally into pTR102. A broad-hast-range and visible promoter-probe vector, pHN127 was constructed and used successfully for the identification of constitutive and inducible promoters from Sinorhizobium fredii HN01.

Cloning, Molecular↗
PubMed1999

[Sequence analysis of the mutated AOX2 promoter region in the Pichia pastoris].

Spontaneous revertants of the AOX1-defective P. pastoris strain have been isolated, which were identified as phenotypically utilize methanol to grow as the wild type. The promoter region of the AOX2 gene from the revertant has been obtained by PCR amplification, and the DNA fragment is 1022 base pair in size. By the analysis of sequencing result and compared with the AOX2 gene sequences recorded in Gene Bank, two point mutations which at positions of -529 and -255(relative to the translation initiation codon) respectively, have been found. Since the positions are located in the AOX2 upstream repression sequences, the mutations may act interfere the repressor to combine with the functional sequences, and increase transcriptional activity. The above result implicated that the P. pastoris' ability to utilize methanol could be increased through modification the upper stream transcriptional regulation region in the AOX2 gene.

Alcohol Oxidoreductases↗
PubMed1999

[Regulating effects of VEGF and ANG II on the frog's pericardial mesothelium, stomata, and angiogenesis].

OBJECTIVE: To observe the regulating effects of vascular endothelial growth factor (VEGF) and angiotensin II (ANG II) on the frog's pericardium, lymphatic stomata, and angionesis so as to understand their influences on the mesothelial permeability, lymphatic stoma regulation, and myocardial hypertrophy. METHODS: VEGF and ANG II were injected into the frog's peritoneal cavity. The results were obtained by using LM, SEM, and computerized imaging analysis. RESULTS: Scattered distributed pericardial stomata were found on the parietal pericardium of the frog with a few sinusoid mesothelial cells. Since there were no blood vessels in the frog's myocardium, its blood supply was directly from the cardiac chambers flowing into the trabecular spaces of the myocardium. The average diameters of the pericardial stomata in VEGF and ANG II groups were 1.50 and 1.79 microns respectively, which were much larger than those in the control group (0.72 micron, P < 0.01). The average distribution density of the stomata was 8.25/0.1 mm2 and 12.80/0.1 mm2 in VEGF and ANG II groups, which was also much higher than that in the control group (3.57/0.1 mm2, P < 0.01). The sinusoid areas in VEGF and ANG II groups were 2443.95 microns 2/0.1 mm2 and 2121.79 microns 2/0.1 mm2, which was larger than that in the control group (995.08 microns 2/0.1 mm2, P < 0.01). No angionesis were found in the frogs of the experimental groups. CONCLUSIONS: VEGF and ANG II strongly regulate the pericardial stomata by increasing their numbers and openings with larger diameters and higher distribution density. They can also increase the sinusoid areas with the result of the higher permeability of the pericardium, which clealy indicated that VEGF and ANG II can speed up the material transfer of the pericardial cavity and play an important role in preventing myocardial interstitial edema. Yet there is no strong evidence showing angionesis in the myocardium.

Angiotensin II↗
PubMed1999

[Identification study on pig's hoofnail].

The identification characteristics of pig's hoofnail on properties and tissue slice was initially probed from the viewpoint of identification in this paper in order to make basis for the systematic research on replacing Squama manitis.

Animals↗
PubMed1999

[Experimental study on pharmacological action of fukean tablet on gastrointestinal tract].

The pharmacological effects of FuKean Tablet(FKT) on gastrointestinal tract were studied. The results showed FKT cured the diarrhea induced by rhubarb or senna, prominently reduced the quantity of feces and delayed the time of excreting charcoal powder in the diarrhea induced by rhubarb or senna model NIH mice; FKT inhibited intestinal propelling-movement in diarrhea induced by senna mmodel NIH mice. FKT inhibited the automatic contraction and Ach induced spasmodic contraction of isolated rabbit intestine(decreased the frequency and intensity of contraction). The above results revealed that the pharmacological base of curing the urgent disease in gastrointestinal tract may be curing the diarrhea, inhibiting intestinal propelling-movement and inhibiting the contraction of intestine.

Animals↗
PubMed1999

[Expression of vimentin in the lenses of vimentin transgenic mice].

PURPOSE: To observe the expression of vimentin in the lenses of vimentin transgenic mice and investigate the role of vimentin in the formation of cataract. METHODS: The 12.7 kb chicken vimentin genes were microinjected into the male pronuclei of ICR mice. The injected embryos were transferred to the pseudopregnant recipient females and then generated several transgenic mice. Twenty mice developed cataract by cross-breeding. Expression of vimentin in 4 cataractous lenses and 4 normal lenses were detected by ABC immunohistochemical method. Usig SDS-PAGE and Western blot technique, we seperated and measured vimentin in the normal and two cataract lenses, in which one was part opacity and the other was complete opacity. RESULTS: Besides in the epithelial cells, vimentin was overexpressed in the cells in anterior cortex and equatorial region in the lenses of transgenic mice. By SDS-PAGE and Western blot, 57 KD urea-soluble protein bands were seperated in normal and cataract lenses and were reacted with vimentin antiserum specifically. In normal lens, partly and completely opaque lenses respectively, the values of average grey density of these bands were 15.56, 34.59 and 33.06 and the percentages of vimentin in urea-soluble fraction were 7.26%, 9.05% and 9.17%, according to the sum of the grey level values of each band. CONCLUSION: Over and ectopic expression of vimentin in the Lenses of transgenic mice inhibits the lens cell differentiation and is linked to cataract formation.

Animals↗
PubMed1999

[The development and clinical application of a multipurpose neuroendoscope].

The multipurpose rigid neuroendoscope MGE-4 has been developed with the application of the self-focussing lens technology. We have been using it to examine and treat 10 neurosurgical patients who suffered from tumours, hydrocephalus, intracerebral haematomas of head injury and hypertensive cerebral haemorrhage. The short-term effect was satisfactory and there was no operative complications. It is considered that Model MGE-4 with the accessories can be used safely for the brain functional subcortical lesion or the deep-seated cystic lesions and haematomas.

Adult↗
PubMed1999

Overexpression of c-fos and Rb proteins in radiation-induced skin ulcers.

We established an animal model of radiation-induced skin ulcers in rats irradiated with 35 to 55 Gy y-rays. The pathological changes were observed for 1 year. Immunohistochemical studies were performed on 72 radiation-induced skin ulcer specimens using c-fos and Rb protein polyclonal antibodies. We found that the overexpression rate of c-fos was 45.8% and of Rb was 63.9%. The overexpression of c-fos was mainly seen in the nuclei of activated squamous epithelial cells and in some fibroblasts and endothelial cells of arterioles in the deep part of the skin ulcers. The overexpression of Rb had the same localization. Our results suggest that the changes in c-fos and Rb proteins may be related to the poor healing of radiation-induced skin ulcers.

Animals↗
PubMed1999

Overexpression of p53 and MDM2 proteins in rat radiation-induced skin ulcers.

We established an animal model of radiation-induced skin ulcer in rats that were locally irradiated with 35 to 55 Gy gamma-rays. The pathological changes were observed for 1 year. Immunohistochemical studies using p53 and MDM2 protein polyclonal antibodies were performed on 72 radiation-induced skin ulcer specimens. The results showed that the overexpression rate of p53 protein was 9.7% and of MDM2 was 19.4%. The overexpression of p53 was chiefly seen in the nuclei of the activated squamous epithelial cells and in the fibroblasts and endothelial cells of arterioles in the deeper part of the skin ulcers. The overexpression of MDM2 had the same localizations. These results suggest that the changes of p53 and MDM2 may be related to the poor healing rate of radiation-induced skin ulcers.

Animals↗
PubMed1999

[Method for the determination of trace Li in serum of cancer patients by tungstate-coated graphite furnace atomic absorption spectrometry].

Using a tungstate coated graphite tube. The sensitivity of Li was significantly increased and trace Li in serum samples was determined by Zeeman graphite AAS with (NH4)2SO4 as a matrix modifier. The effects of different metal ions and biological matrix were eliminated. The characteristic concentration is 5.53 x 10(-3) microg x mL(-/1)%. The recovery is greater than 93.72%. The relative standard deviation is less than 8.93%.

Humans↗
PubMed1999

[Time-resolved fluorescence investigations of aggregation in Langmuir-Blodgett multilayers of hemicyanine dye].

UV-visible absorption and steady-state and time-resolved fluorescence techniques were used to investigate the aggregation behavior in Y-type hemicyanine Langmuir-Blodgett (LB) multilayers. Hemicyanine molecules formed H aggregates in LB films leading to blue-shifts of the absorption and fluorescence bands with respect to those of monomeric hemicyanine in chloroform solutions. The aggregates in LB films were dissociated by mixing with arachidic acid. The measurement of fluorescence decay profiles could be used to quantitatively characterize the lifetime, weights and size of aggregates.

English Abstract↗
PubMed1998

Exon-I is involved in positive as well as negative regulation of human angiotensinogen gene expression.

Angiotensinogen is the glycoprotein precursor of one of the most potent vasoactive hormones, angiotensin-II. Angiotensinogen gene is primarily expressed in the liver, and this gene locus is linked with human essential hypertension. We show here that a mutation in exon-I reduces the basal expression of the human angiotensinogen gene in liver cells. We also show that a nucleotide sequence in exon-I binds to liver-enriched transcription factor HNF-3 and a ubiquitous factor AP4. Our studies also show that transient transfection of an expression vector containing AP4 coding sequence downregulates the expression of reporter constructs containing human angiotensinogen gene promoter. By contrast, co-transfection of an expression vector containing HNF-3beta coding sequence increases the expression of these reporter constructs. The human angiotensinogen gene has a C/A polymorphism located at -20, and we have shown that estrogen receptor-alpha binds to this sequence when nucleoside A is present at this site. We show here that co-transfection of an expression vector containing AP4 coding sequence reduces estrogen-induced promoter activity of reporter constructs containing human angiotensinogen gene promoter (with nucleoside A at -20) attached to the CAT gene. These studies partly explain the molecular mechanisms involved in tissue-specific expression of the human angiotensinogen gene.

Angiotensinogen↗
PubMed1998

Keratinocyte growth factor down-regulates expression of the sucrase-isomaltase gene in Caco-2 intestinal epithelial cells.

The molecular mechanisms that regulate the proliferation and differentiation of intestinal mucosal epithelial cells are not well understood. Keratinocyte growth factor (KGF) is an epithelial cell-specific growth factor that may be involved in the maintenance of mucosal epithelial populations and in mediating epithelial repair after injury. The sucrase-isomaltase (SI) gene, which encodes an enterocyte brush border disaccharidase, has served as a model for study of intestinal-specific gene expression and differentiation. KGF down-regulated SI mRNA and protein expression in Caco-2 intestinal epithelial cells but not the expression of other brush border enzymes. The down-regulation was dose- and time-dependent and specifically blocked by anti-KGF antibodies. Transfection experiments using SI promoter constructs demonstrated that KGF decreased SI gene transcription. In contrast, the stability of SI mRNA was not affected by incubation of Caco-2 cells with KGF. Electrophoretic mobility shift analysis demonstrated that binding of nuclear proteins to the SI footprint (SIF) 3 and SIF4 regulatory elements within the SI promoter region was increased in Caco-2 cells that had been incubated with KGF. In transfection experiments using a construct in which tandem copies of the SIF4-binding site were inserted upstream of the SV40 promoter and luciferase gene, incubation with KGF resulted in a significant decrease in luciferase activity. However, transfection with a similar construct containing tandem copies of SIF3 had no significant effect on SV40 promoter activity following KGF treatment. SIF4 may bind E4BP4, a previously identified transcriptional repressor protein. This factor may in part mediate the decrease in SI transcription by KGF in Caco-2 cells.

Caco-2 Cells↗
PubMed1998

Mucosal immunisation with papillomavirus virus-like particles elicits systemic and mucosal immunity in mice.

It has been shown previously that recombinant virus-like particles (VLPs) of papillomavirus can induce VLP-specific humoral and cellular immune responses following parenteral administration. To test whether mucosal administration of bovine papillomavirus type 1 (BPV1) VLPs could produce mucosal as well as systemic immune responses to VLPs, 50 micrograms chimeric BPV1 VLPs containing an HPV16 E7 CTL epitope (BPVL1/E7 VLP) was administered intranasally to mice. After two immunisations, L1-specific serum IgG and IgA were observed. L1-specific IgG and IgA were also found in respiratory and vaginal secretions. Both serum and mucosal antibody inhibited papillomavirus VLP-induced agglutination of RBC, indicating that the antibody induced by mucosal immunisation may recognize conformational determinants associated with virus neutralisation. For comparison, VLPs were given intramuscularly, and systemic and mucosal immune responses were generally comparable following systemic or mucosal delivery. However, intranasal administration of VLP induced significantly higher local IgA response in lung, suggesting that mucosally delivered HPV VLP may be more effective for mediating local mucosal immune responses. Intranasal immunisation with HPV6b L1 VLP produced VLP-specific T proliferative responses in splenocytes, and immunisation with BPVL1 VLP containing an HPV16 E7 CTL epitope induced E7-specific CTL responses. We conclude that immunisation with papillomavirus VLPs via mucosal and intramuscular routes, without adjuvant, can elicit specific antibody at mucosal surfaces and also systemic VLP epitope specific T cell responses. These findings suggest that mucosally delivered VLPs may offer an alternative HPV VLP vaccine strategy for inducing protective humoral immunity to anogenital HPV infection, together with cell-mediated immune responses to eliminate any cells which become infected.

Administration, Intranasal↗
PubMed1998

A novel transcription factor, ELF5, belongs to the ELF subfamily of ETS genes and maps to human chromosome 11p13-15, a region subject to LOH and rearrangement in human carcinoma cell lines.

The ETS transcription factors are a large family implicated in the control of cellular proliferation and tumorigenesis. In addition, chromosomal translocations involving ETS family members are associated with a range of different human cancers. Given the extensive involvement of ETS factors in tumorigenesis, it becomes important to identify any additional ETS genes that may also play oncogenic roles. We identify a novel gene, ELF5, that appears to belong to the ELF (E74-like-factor) subfamily of the ETS transcription factor family, based upon similarity within the 'ETS domain'. ELF5 displays a similar, but more restricted, expression pattern to that of the newly isolated epithelium-specific ETS gene, ELF3. Unlike most other ETS family members, ELF5 is not expressed in hematopoietic compartments, but is restricted to organs such as lung, stomach, kidney, prostate, bladder and mammary gland. ELF5 is localized to human chromosome 11p13-15, a region that frequently undergoes loss of heterozygosity (LOH) in several types of carcinoma, including those of breast, kidney and prostate. We find that ELF5 expression is not detectable in a number of carcinoma cell lines, some of which display loss or rearrangement of an ELF5 allele. Similar to other ETS family members, ELF5 displays specific binding to DNA sequences containing a GGAA-core. In addition, ELF5 is able to transactivate through these ETS sequences, present upstream from a minimal promoter. Our data suggest that ELF5 may play roles in mammary, lung, prostate and/or kidney function, and possibly also in tumorigenesis.

Amino Acid Sequence↗
PubMed1998

TAFII mutations disrupt Dorsal activation in the Drosophila embryo.

In this study, we present evidence that the Dorsal activator interacts with limiting amounts of the TFIID complex in the Drosophila embryo. In vitro transcription reactions and protein binding assays implicate the TAFII110 and TAFII60 subunits of the TFIID complex in contributing to Dorsal-mediated activation. Mutations in TAFII110 and TAFII60 result in altered patterns of snail and twist transcription in embryos derived from dl/+ females. These results suggest that TAFIIs contribute to the activation of transcription in vivo and support the hypothesis that subunits of TFIID may serve as targets of enhancer binding proteins.

Animals↗
PubMed1998

Evaluation of GM1 ganglioside-mediated apoptosis in feline thymocytes.

Cats with inherited GM1 gangliosidosis (GM1 mutant cats) have premature thymic involution characterized by decreased total thymocytes primarily affecting the CD4+ CD8+ subpopulation. While GM1 mutant cats have increased cell surface GM1 gangliosides, as determined by cholera toxin B binding, on both thymocytes and peripheral lymph node cells only thymocytes show increased apoptosis. To determine if GM1 gangliosides can increase the occurrence of apoptosis in feline thymocytes directly, we added exogenous GM1 ganglioside (GM1) to feline thymocyte primary cultures and compared the results to apoptotic changes seen in untreated cells or in cells treated with dexamethasone (Dex), a known inducer of thymocyte apoptosis in other species. Incorporation of exogenous GM1 into thymocyte cytoplasmic membranes was confirmed by flow cytometric analyses of cholera toxin B labelling. Apoptosis in feline thymocytes was analyzed by electron microscopy, spectrophotometric evaluation of DNA fragmentation, flow cytometric enumeration of apoptotic nuclei, and gel electrophoretic analysis of degraded DNA. Alterations in percentages of thymocyte immunophenotype following GM1 incorporation were determined by flow cytometric analyses of labelled cell surface markers for feline CD4 and CD8. Because in vitro addition of GM1 gangliosides has been reported in other species to decrease surface expression of CD4 on both thymocytes and peripheral lymphocytes, we evaluated GM1-associated down-regulation of CD4 on the surface of feline thymocytes and peripheral lymph node cells by flow cytometry. Additionally, we compared the apoptotic response of the more mature peripheral lymph node cells to the less mature thymocytes. Our results indicate that incorporation of exogenous GM1 into feline thymocyte cell membranes produces a dose-dependent increase of apoptotic cell death. Although, CD4 expression on both feline thymocyte and lymph node cell membranes was abruptly decreased after introducing exogenous GM1, enhanced apoptotic death was observed only in thymocytes, not in lymph node cells at the same GM1 concentration. Enhancement of thymocyte apoptosis appears to be age-related since cells derived from cats <3 months of age were more vulnerable than those from cats >3 months of age.

Aging↗