PubMed Health⌕ Search

Biomedical subjects

Z Wei

Publications and source records attributed to Z Wei.

At least 73 records · Page 4Linked to original sources
PubMed1997

The SpHE gene is downregulated in sea urchin late blastulae despite persistence of multiple positive factors sufficient to activate its promoter.

Previous studies of the regulatory region of the SpHE (hatching enzyme) gene of the sea urchin Strongylocentrotus purpuratus (Wei, Z., Angerer, L.M., Gagnon, M.L. and Angerer, R.C. (1995) Characterization of the SpHE promoter that are spatially regulated along the animal-vegetal axis of the sea urchin embryo. Dev. Biol. 171, 195-211) have shown that approximately 330 bp is necessary and sufficient to promote high level expression in embryos of transgenes that reproduce the spatially asymmetric pattern of endogenous gene activity along the maternally determined animal-vegetal embryonic axis. Furthermore, SpHE regulatory elements appear to be redundant since several different combinations are sufficient to elicit strong promoter activity and many subsets function like the endogenous gene only in non-vegetal cells of the blastula (Wei, Z., Angerer, L.M. and Angerer, R.C. (1997) Multiple positive cis-elements regulate the asymmetric expression of the SpHE gene along the sea urchin embryo animal-vegetal axis. Dev. Biol., 187, 71-88). Here we demonstrate by in vivo footprinting that many cis elements on the endogenous promoter are occupied when the gene is active in early blastulae, but the binding of corresponding trans factors is significantly reduced when the gene becomes inactive in late blastulae. In addition, downregulation of the promoter is accompanied by a transition from a non-nucleosomal to a nucleosome-like chromatin structure. Surprisingly, in vitro DNase I footprints of the 300 bp promoter using nuclear protein extracts from early and late blastulae are not detectably different and neither this sequence, nor a longer one extending to -1255, reproduces the loss of endogenous SpHE transcriptional activity after very early blastula stage. These observations imply that temporal repression of SpHE transcription involves a decrease in accessibility of the promoter to activators that are nevertheless present in nuclei and capable of activating transgene promoters. Temporal, but not spatial, downregulation is therefore likely to be regulated by negative activities functioning outside the -1255 promoter region which may serve as direct repressors or mediate an inactive chromatin structure.

Animals↗
PubMed1997

Effect of jiawei shenqi dihuang tang on the content of urinary protein in patients with diabetic nephropathy.

42 cases of diabetic nephropathy (DN) diagnosed as the type of kidney deficiency and blood stasis were treated with Jiawei Shenqi Dihuang Tang. The therapeutic effect demonstrated that various kinds of symptoms and sings were significantly improved. There was significant difference in the qualitative and quantitative examinations of urinary protein between pre- and post-treatment (P < 0.05).

Adult↗
PubMed1997

[Immunohistochemical study of p53, c-erbB-2 and nm23 proteins in human gastric cancer].

OBJECTIVE: To evaluate p53, c-erbB-2 and nm23 oncoproteins in diagnosis of gastric cancer. METHODS: The expression of p53, c-erbB-2 and nm23 oncoproteins was detected immunohistochemically in 141 surgically resected specimens and 93 endoscopic biopsy specimens of gastric cancer. RESULTS: The positive rate of p53, c-erbB-2 and nm23 immunoreactivity was 45.8-56.3%, 18.3-31.2% and 72.9%-81.3% respectively. No immunoreactivity was observed in the tumor-adjacent normal mucosa and non-tumor biopsy specimens. The presence of c-erbB-2 was correlated with the size of tumor, grade of tumor differentiation and Lanren classification. Patients with c-erbB-2 positive tumor had lower 5-year survival rate. The expression of nm23 was negatively correlated with the depth of invasion, and lymphnode metastasis. The positive rates of p53, c-erbB-2 and nm23 had no statistical difference between biopsy and resected specimens. CONCLUSION: Determination of p53, c-erbB-2 and nm23 oncoproteins immunohistochemically might be useful in the diagnosis and differential diagnosis, clinical staging, and predicting prognosis of gastric cancer.

Adenocarcinoma↗
PubMed1997

[Experimental research on the prediction of human body thermal responses in special hot environment].

The assessment of thermal environment is very important in the research of human body-thermal environment system. On the basis of systematic study, the characteristics and the components of human body-thermal environment system have been analyzed, the stationary mathematical model of human body-thermal environment system was established. Prediction and Assessment System for Thermal Environment (PASTE system) was developed. It consists of thermal environment monitor and simulator based on the IBM PC/XT computer with suitable hardware and software. Thermal environment monitor can measure fifteen parameters continuously including dry bulb temperature, dewpoint temperature, air velocity and thermal radiation in six directions. The simulator can simulate different heat exchange processes of human body-thermal environment system and human thermal responses. PASTE system is integrated with monitor and computer simulator. Test results showed that the differences between experimental result and predicted result were about +/-10%.

Body Temperature Regulation↗
PubMed1997

[Basic ovarian status and follicular response to superovulation stimulation in an in vitro fertilization and embryo transfer program].

OBJECTIVE: To study the relationship between patient age, cycle day 3 basal ovarian status, serum estradiol (E2) level and the ovarian response in an in vitro fertilization and embryo transfer (IVF-ET) program. METHOD: 102 cases and 102 cycles of IVF-ET patients with regular menstrual period and normal cycle day 3 basal follicular-stimulating hormone (FSH < 20 IU/L) level were studied. The same superovulation regimen was employed. The ovarian response was classified as low when follicle number (diameter > 10 mm) was fewer than 3 on the day of hCG injection, moderate when the number was 3-14, and high when follicle number exceeded 14. RESULTS: (1) Patients older than 35 years tended to be low responders; women younger than 30 years usually responded well with production of more than 15 follicles. (2) The number of cycle day 3 follicles was positively correlated with the number after stimulation with gonadotropin. When total basal follicle number in both ovary exceeded 20, ovarian an hyperstimulation syndrome should be watched out. (3) On cycle day 3 the diameter of the largest follicle was negatively correlated with the ovarian response. In low responders the diameter of the largest follicle was usually larger than 4 mm. (4) Despite of the different size and number of the cycle day 3 follicles the serum E2 level was quite similar. CONCLUSION: Age and basal ovarian status including the number and size of the antral follicles are valuable factors to be considered in the prediction of ovarian response to the same gonadotrophic stimulation protocol.

Adult↗
PubMed1997

[Regulation of ovarian follicular development by epidermal growth factor in IVF superovulation cycles].

OBJECTIVE: To study the role of epidermal growth factors (EGFs) in the regulation of ovarian follicular development in in vitro fertilization (IVF) superovulation cycles. METHODS: In situ hybridyzation and immunochemistry were used to locate EGF, transforming growth factor alpha (TGF alpha) and their receptor (EGFR) in 10 normal ovarian specimens and in 5 granulosa cell samples obtained from IVF egg retrieval procedure. Radioimmunoassay was used for 6 sex hormones and radioreceptor assay for EGFs (mainly including EGF and TGF alpha) determinations in the serum and follicular fluid. RESULTS: (1) EGF was not detected in the ovary, while EGFR and TGF alpha were found to be present in human granulosa cells. (2) Serum EGFs levels increased with the development of follicles, and EGFs levels in the follicular fluid were higher than those of the matched plasma. No correlation was found between EGFs and sex hormones. CONCLUSIONS: TGF alpha but not EGF might be synthesized locally, acting on the granulosa cells in an autocrine fashion through EGFR in granulosa cells. Serum EGFs levels (including EGF and TGF alpha) might be stimulated by exogenous gonadotropins.

Adult↗
PubMed1997

[Insulin growth factor I in the development of ovarian follicles].

OBJECTIVE: To investigate the role of insulin growth in factor-1 (IGF-1) in the development of ovarian follicles under the stimulation of gonadotropins in an in-vitro fertilization (IVF) program. METHODS: Radioimmuoasssy was used to determine the levels of sex hormones and IGF-1 in the serum and follicular fluid samples. In situ hybridyzation was used to detect the expression of IGF-1 and IGF-1 receptor (IGF-1R) in the granulosa cell obtained from follicular aspiration in women undergoing IVF egg retrieval procedures. RESULTS: (1) Levels of plasma IGF-1 increased with the development of follicles (P < 0.001); follicular fluid (FF) IGF-1 levels were lower than those of matched plasma; FF-IGF-1 decreased with increase of follicle numbers (P < 0.01), e.g. in patients with less than 2 follicles (diameter > or = 15 mm) at the tine of ovum pick-up the FF-IGF-1 levels were much higher than patients with more than 2 follicles (P < 0.05). (2) Significant negative correlation was found between plasma IGF-1 and plasma E2 and also between FF-IGF-1 and FF-follicle-stimulating hormone (FSH) during ovum pick-up (P < 0.01). (3) IGF-1 mRNA was not, while IGF-1R mRNA was found to be present in the human granulosa cells taken at ovum pick-up. CONCLUSIONS: Plasma IGF-1 production might be stimulated by gonadotropins and distributed into the ovarian follicles by diffusion from peripheral circulation, acting upon the granulosa cells and therefore plays a complementary role with the gonadotropins in the regulation of follicular development.

Embryo Transfer↗
PubMed1996

Hybridization properties of oligodeoxynucleotide pairs bridged by polyarginine peptides.

The hybridization properties of a series of probes, based on two 9mer oligodeoxynucleotides (designated as I and II) having an appended oligoarginine chain (Rn) to produce peptide-oligonucleotide conjugates or peptide-bridged oligonucleotide pairs (e.g. Rn-I or II-Rn-I), were investigated. For the double-linked probes, we found that the peptide bridge induces the two 9mers to bind complementary single-stranded DNA or RNA targets with substantially enhanced thermal stability. The resulting hybrid with complementary DNA was found to assume a 1:1 complex in the B conformation as judged by UV mixing curves and CD spectroscopy. Complexes of single or double-linked probes with complementary RNA exhibited sensitivity to RNase H digestion. The influence of the identity and chirality of the repeating unit in the bridge, the length of the bridge, the gap size and the salt concentration on the hybridization properties of this new class of oligonucleotide probes was also studied. Our data reveal that these compounds exhibit properties that should prove useful in the development of antisense strategies.

Amino Acid Sequence↗
PubMed1996

Sulfated malto-oligosaccharides bind to basic FGF, inhibit endothelial cell proliferation, and disrupt endothelial cell tube formation.

The interaction of basic FGF (bFGF) with heparin, heparan sulfate and related sugars can potentiate or antagonize bFGF activity, depending on the size of the saccharide used. Oligosaccharides based on heparin structures, as small as six sugar residues, have been demonstrated to bind to bFGF and block its activity, while larger structures (> 10 sugar residues) tend to potentiate bFGF. In this study we have synthesized a series of compounds designed to test the requirements of size and sulfation for binding of oligosaccharides to bFGF. These oligosaccharides are not derived from heparin, but rather, are linear chains of glucose linked alpha 1-4 (malto-oligosaccharides) that have been chemically sulfated. In addition to bFGF binding, these compounds were tested for their ability to block basic functions of endothelial cells that are known to be mediated, at least in part, by bFGF. We report that the ability of sulfated malto-oligosaccharides to block binding of bFGF to heparan sulfate was dependent on the size (at least a tetrasaccharide is required), and the degree of sulfation. The activity profile in the bFGF ELISA closely correlated with the ability of these compounds to block REEC or HMVEC tube formation on Matrigel. There was a similar relationship of size and sulfation to the ability of the sulfated malto-oligosaccharides to inhibit endothelial cell growth for most human and rat EC types tested. The single exception was REEC cell growth. One isolate of these cells was stimulated by sulfated malto-oligosaccharides rather than inhibited by them, while a second isolate was neither stimulated nor inhibited. This stimulation showed no correlation with inhibition of bFGF binding in the ELISA assay, suggesting that growth of this cell type was probably not dependent on bFGF. Compounds derived from this series of sulfated, malto-oligosaccharides have the potential to function as bFGF antagonists, are relatively easy to produce, and possess relatively low anticoagulant properties.

Animals↗
PubMed1996

Gel shift assay: demonstration of enhanced binding of oligo(delta)-L-ornithine-oligodeoxynucleotide conjugates to complementary DNA and RNA.

An increase in melting temperature for DNA:DNA duplexes had been observed previously (Zhu et al. Antisense Res. Dev. 3:349-356, 1993) when an oligo(delta)ornithine moiety was covalently appended to a short oligodeoxynucleotide. We now report the analysis of duplex formation by electrophoretic gel shift analysis. In the particular example studied, an increase in Tm of 4 degrees C was found to correspond to about a fivefold increase in binding constant. A similar enhancement by the appended cationic peptide was observed when the target strand was RNA. The use of a competitive assay format for avoidance of adsorptive loss at low concentrations (< 10(-7)M) of the oligonucleotide-oligo(delta)ornithine conjugate is presented.

Base Sequence↗
PubMed1996

Agrobacterium tumefaciens mediated transformation of Orychophragmus violaceus cotyledon and regeneration of transgenic plants.

Excised cotyledons of Orychophragmus violaceus were used as explants for tissue culture. They were cultured on the MS medium supplemented with BA (3 mg/L) and NAA (0.2 mg/L). When the regenerated buds were 2 cm long, they were excised and transferred onto 1/2 MS medium with IBA (0.03 mg/L), then the whole plants were regenerated. The frequency of plant regeneration was 100%. Subsequently, the genetic transformation of O. violaceus was studied. After 2-3 days of cocultivation with Agrobacterium tumefaciens strain A208se (pTiT37, pROA93), the cotyledons were transferred onto the selection medium containing 25 mg/L Km and 250 mg/L Ap. After shoots emerged, they were excised and transferred onto the rooting medium containing 25 mg/L Km and 100 mg/L Cef. The roots were formed within 4-5 weeks. The whole plants were transplanted into pots and grew well. The frequency of plant regeneration was about 51%. The regenerated plants showed high enzymatic activities of beta-glucuronidase and neomycine phosphotransferase II. Southern blot analysis confirmed that NPTII gene had been stably integrated into the chromosomal genome of O. violaceus. The transformation frequency was 5.6%. The first transgenic plant of O. violaceus is being reported.

Agrobacterium tumefaciens↗
PubMed1996

[Displaying of infrared thermogram of temperature character on meridians].

In this work we have observed the skin temperature of central line of the back and chest-abdomen on the human body truck by the infrared thermography. Here care the results: (a) Of all the volunteers, 57.1% central lines of the back and 7.7% central lines of the chest-abdomen of the volunteers are the longitudinal high thermal lines in normal state. (b) After moxibustion at Mingmen (GV 4) point, the temperature of 70.4% central lines of the back is going up. After moxibustion at Zhongwan (CV 12) point, the temperature of 56.0% central lines of the chest-abdomen is going up. The high thermal lines are longer and their continuity is hotter after moxibustion. (C) The lines on the back which are about 20 approximately 50 centimetres are longer than those on the chest-abdomen which are about 10-30 centimetres. The results suggest that the high thermal lines are the objective display of the temperature character on the Governor and Conception vessel. The formation of high thermal line may have some relationship with the compact connective tissue or microcirculation.

Acupuncture Points↗
PubMed1995

An enzyme-linked immunosorbent assay using biotinylated heparan sulfate to evaluate the interactions of heparin-like molecules and basic fibroblast growth factor.

Basic fibroblast growth factor (bFGF) is a member of the heparin-binding growth factor family that interacts with cell surface heparan sulfate (HS) proteoglycans and extracellular matrix heparin. Here we report the development of a simple and sensitive assay that used biotinylated HS or heparin to bind to bFGF coated onto 96-well microtiter plates. Bound labeled HS or heparin was reacted with enzyme-linked streptavidin and results were recorded as optical density. Increased molar excess of biotin resulted in increased incorporation of biotin and higher signal without compromising binding. Glycosaminoglycans and modified heparins were assayed for their ability to compete with biotinylated HS for binding to bFGF. Inhibition of that binding by heparin and HS but not by chondroitin sulfate A or C, dermatan sulfate, or keratan sulfate demonstrated the specificity of the glycosaminoglycan binding. Structural modifications of heparin produced various degrees of inhibition with high structural specificity. Although removal of N-sulfates or 2,3-O-sulfate groups resulted in significant loss of inhibition, removal of 6-O-sulfates had little affect on binding. Carboxyl reduction or N-acetylation following N-desulfation produced heparinoids with moderate changes in binding capacity. Results from this assay are in agreement with previous data from our laboratory and reports from other researchers with respect to the specificity of glycosaminoglycan binding to bFGF and the role of 2,3-O- and 6-O-sulfate groups of heparin. The flexibility of this assay, in both the amount of label incorporated and the variability of solid substrate, makes this an excellent tool to study other heparin binding proteins.

Binding, Competitive↗
PubMed1995

Drug-induced heat-shock preconditioning improves postischemic ventricular recovery after cardiopulmonary bypass.

BACKGROUND: Heat-stress preconditioning of mammalian heart has been found to confer protection against ischemic reperfusion injury. Heat shock is generally provided by warming the animal by mechanical means, which is often impractical in a clinical setting. Amphetamine, a sympathomimetic drug, can elevate the body temperature as a result of enhanced endogenous lipolysis. In this study, we examined the effects of heat shock induced by amphetamine on postischemic myocardial recovery in a setting of coronary revascularization for acute myocardial infarction. METHODS AND RESULTS: Adult Yorkshire swine were injected with amphetamine (3 mg/kg IM) (n = 12), and body temperature was continuously monitored. For control studies, the pigs were injected with saline (n = 12). Five swine in each group were killed after 3 hours to obtain biopsies of vital organs to measure heat-shock protein (HSP) mRNAs. After 40 hours, the remaining 7 pigs in each group were placed on cardiopulmonary bypass, and the isolated, in situ heart preparations were subjected to 1 hour of occlusion of the left anterior descending coronary artery followed by 1 hour of global hypothermic cardioplegic arrest and 1 hour of reperfusion. Postischemic myocardial performance was monitored by measuring left ventricular (LV) pressure, its dP/dt, myocardial segment shortening, and coronary blood flow. Cellular injury was examined by measurement of creatine kinase release. The antioxidant enzymes superoxide dismutase and catalase were also assayed. Amphetamine treatment was associated with the induction of mRNAs for HSP 27, HSP 70, and HSP 89 in all the vital organs, including heart, lung, liver, kidney, and brain. Amphetamine also enhanced superoxide dismutase and catalase activities in the heart. Significantly greater recovery of LV contractile functions was noticed, as demonstrated by improved recovery of LV developed pressure (61% versus 52%), LV dP/dtmax (52% versus 44%), and segment shortening (46.2% versus 10%) and reduced creatine kinase release in the amphetamine group. CONCLUSIONS: The results demonstrate that amphetamine can induce whole-body heat shock that can precondition the heart, enhancing cellular tolerance to ischemia-reperfusion injury. Amphetamine is a sympathomimetic drug that may be used for preconditioning.

Amphetamine↗
PubMed1995

Characterization of the SpHE promoter that is spatially regulated along the animal-vegetal axis of the sea urchin embryo.

To understand how the maternally determined animal-vegetal polarity of the sea urchin embryo is established, we have begun to examine the regulatory apparatus of the gene encoding the Strongylocentrotus purpuratus hatching enzyme (SpHE). Previous studies have shown that the pattern of SpHE mRNA accumulation reflects the animal-vegetal developmental axis in that transcription is strongly upregulated during early cleavage in more animal blastomeres, but not in those around the maternally specified vegetal pole of the 16-cell embryo [Reynolds et al., Development 114, 769-786 (1992)]. Tests of SpHE promoter function in vivo using chloramphenicol acetyltransferase and beta-galactosidase enzymatic reporters define a regulatory region within several hundred nucleotides of the transcription initiation site. This region is sufficient to mediate both strong expression in the early blastula and spatially correct transcription. However, neither this region nor longer upstream sequences are sufficient to reproduce the transcriptional downregulation after very early blastula stage that is observed for endogenous genes. Biochemical assays of protein-DNA interactions within the regulatory region identify at least nine sites binding at least six different factors. These cis elements include Otx (an orthodenticle homologue), CCAAT, ets-related, and three unidentified motifs. Deletions and/or replacements of these cis-elements, alone and in combination, indicate that no single factor is essential for SpHE promoter activity, but instead that various combinations of subsets of these elements are capable of eliciting levels of transcription similar to those of the unaltered regulatory region. This density of regulatory elements is consistent with the intense transcription of endogenous SpHE genes during cleavage.

Animals↗