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Biomedical subjects

D Huang

Publications and source records attributed to D Huang.

At least 91 records · Page 5Linked to original sources
PubMed2000

[Identification of cry-type genes of 31 Bacillus thuringiensis isolates and analysis of their expression product].

In this study, cry-type gene of 31 isolates of Bt had been identified using PCR-RFLP identification system, and SDS-PAGE analysis and bioassay had been performed. 25 strains containing cry1 type gene express 130-150 kD protein and 16 of them contain cry1I gene, which codes 80 kD protein and is larvicidal to both lepidopteran and coleopteran species. 15 strains contain both cry1 and cry2 type gene; 10 strains contain unknown cry-type gene; 6 strains don't contain seven identified cry-type gene. Result of bioassay shows that the strains containing both cry1 and cry2 gene have high toxicity to lepidopteran order, 7 of them are strongly insecticidal to Pristiphora beijingensis and Lymantria dispar larvae; the strains containing cry1Ab + 1Ac + 2A or cry1Aa + 1Ac + 2A have high activity to Heliothis armigera; no cry gene, no activity. It is indicated that identification of cry-type gene and its analysis of SDS-PAGE protein can predict insecticidal activity of Bt isolates, and it is no pertinency between cry-type gene and serotype of Bt strain.

Animals↗
PubMed2000

[Expression and synergism of two cry insecticidal protein genes in Pseudomonas fluorescens].

Several engineered Pseudomonas fluorescens(Pf) strains were constructed mainly based on a Pseudomonas plasmid pJMS6 alpha-lac and two insecticidal crystal protein genes of Bacillus thuringiensis, cry1Ac and cry2Aa, and the host Pf strain, P303, which was with highly antifungal activity to some plant disease fungi and colonizing ability on a wide range of plants. The DNA introduction was confirmed by PCR-RFLP and Southern blot. The 132 kD insecticidal protein was detected in IPP101 and IPP202 by SDS-PAGE and rhombic insecticidal protein crystals of them were observed through electron microscope, also indicating that cry1Ac gene was highly expressed. The results of insecticidal bioassay indicated that IPP101 was more toxic than IPP201, and IPP202 was the most toxic among the 3 strains. LC50 to the neonates of cotton boll worm(Helicoverpa armigera) were 0.02604, 0.00812 and 0.00186 mL/g feed, consecutively. In IPP202, two gene products showed significant synergism, with the co-toxicity coefficient of 332.8.

Animals↗
PubMed2000

[Clinical analysis of evisceration with hydroxyapatite implant].

PURPOSE: To evaluate the clinical effect and safety of evisceration with hydroxyapatite (HA) orbital implant. METHODS: A retrospective analysis of all eviscerations with HA implant performed between January 1998 and May 2000 in Zhongshan Ophthalmic Center was completed. Patient records were reviewed for demographic data, surgical indication, sphere size, clinical outcome, and complications. The average follow-up interval was 11.6 months (2-24 months). RESULTS: Primary evisceration with HA implantation was performed in total 78 cases. All patients underwent successful surgery without major complications. There was no case with those complications, including implant extrusion, exposure and implant dislocation, in the series examination. No patient has symphathetic ophthalmia during follow-up interval. CONCLUSION: In strict selected cases with surgical indication of evisceration, primary evisceration with HA implantation is a safe and effective method for treating patients with a blind, painful or atrophic eye.

Adolescent↗
PubMed2000

[Study of polyaluminium ferric chloride (PAFC) aqueous solutions visible spectra: the relationship among their absorbance at 460 nm, basicities and total Fe(III) concentration of PAFC solutions].

The visible spectra of forty-five synthesized polyaluminium ferric chloride (PAFC) aqueous solutions with different [OH]/[Al + Fe] (B) and nAl/nFe(molar ratio) were investigated. The results showed that their absorbances A of shoulder at 460 nm are all linear interrelationship with their B. We made the curve of absorbance A of PAFC with same B vs. nAl/nFe, there was a turning point. All of these points just located at the places of pH value rising higher in pH- nAl/nFe diagrams. For these reason, we thought that these points stand for the dynamic equilibrium of OH- between the polynucleus hydroxyl Fe(III) and Al(III). These points made certain relationship among the absorbance A at 460 nm, basicities and total Fe(III) concentration of PAFC solutions.

English Abstract↗
PubMed1999

The MEK pathway is required for stimulation of p21(WAF1/CIP1) by transforming growth factor-beta.

Transforming growth factor-beta (TGF-beta)can induce the cyclin-dependent kinase inhibitors p21 and p15 in a variety of cell types. We have shown previously that Smad3 is required for the growth inhibitory activity of TGF-beta, whereas overexpression of Smads is not sufficient to activate the expression of p21 in HaCaT cells. These data suggest that an additional signaling pathway may be involved in stimulating p21 in HaCaT cells. Given the recent finding that the mitogen-activated protein kinase (MAPK) pathway can cause p21 induction and arrest cells, we examined the involvement of this pathway for p21 and p15 induction by TGF-beta. We found that TGF-beta can regulate the MAPK pathway, leading to the increased transactivation ability of transcription factor Elk. Constitutively active components in the MAPK pathway activate p21 expression, and inhibitors or dominant negative constructs for the MAPK pathway significantly decrease p21 induction by TGF-beta. Both constitutively active MEK and inhibitors for MEK have no effect on Smad activity, including DNA binding, localization, and interaction with coactivator p300/CBP. These findings suggest that the MAPK pathway may be an independent pathway that is involved in p21 and p15 induction by TGF-beta.

Benzoquinones↗
PubMed1999

Mammalian Cdk5 is a functional homologue of the budding yeast Pho85 cyclin-dependent protein kinase.

Mammalian Cdk5 is a member of the cyclin-dependent kinase family that is activated by a neuron-specific regulator, p35, to regulate neuronal migration and neurite outgrowth. p35/Cdk5 kinase colocalizes with and regulates the activity of the Pak1 kinase in neuronal growth cones and likely impacts on actin cytoskeletal dynamics through Pak1. Here, we describe a functional homologue of Cdk5 in budding yeast, Pho85. Like Cdk5, Pho85 has been implicated in actin cytoskeleton regulation through phosphorylation of an actin-regulatory protein. Overexpression of CDK5 in yeast cells complemented most phenotypes associated with pho85Delta, including defects in the repression of acid phosphatase expression, sensitivity to salt, and a G(1) progression defect. Consistent with the functional complementation, Cdk5 associated with and was activated by the Pho85 cyclins Pho80 and Pcl2 in yeast cells. In a reciprocal series of experiments, we found that Pho85 associated with the Cdk5 activators p35 and p25 to form an active kinase complex in mammalian and insect cells, supporting our hypothesis that Pho85 and Cdk5 are functionally related. Our results suggest the existence of a functionally conserved pathway involving Cdks and actin-regulatory proteins that promotes reorganization of the actin cytoskeleton in response to regulatory signals.

Actins↗
PubMed1999

Polymorphisms at - 174 and in the 3' flanking region of interleukin-6 (IL-6) gene in patients with myasthenia gravis.

We examined the bi-allelic polymorphism at - 174 in the promoter region and the polymorphism in the 3' flanking AT rich region of the interleukin-6 (IL-6) gene in Swedish patients with myasthenia gravis (MG) and ethnically matched healthy individuals. There was no association between the polymorphisms and the disease. There was no relation of the polymorphisms to the clinical variables, the thymic histopathologies, the level of serum acetylcholine receptor antibodies or the concentrations of IgG and its subclasses. Our data yield no evidence for the IL-6 gene contributing to the disease susceptibility.

AT Rich Sequence↗
PubMed1999

cDNA and structural organization of the gene Pole1 for the mouse DNA polymerase epsilon catalytic subunit.

The cDNA and the gene for the mouse DNA polymerase epsilon catalytic subunit were cloned. The deduced protein sequence shows remarkable evolutionary conservation in DNA polymerase epsilon family. However, several conserved elements involved in template-primer binding differ from those of other class B polymerases. This is likely to reflect a distinctive function of the enzyme. The gene that was assigned to chromosome 5 region E3-E5, consists of 49 exons and has a non-conforming splice site in the junction of exon and intron 13. A CpG island covers the promoter region which contains several putative consensus elements critical for S phase upregulated and serum responsive promoters.

Amino Acid Sequence↗
PubMed1999

Structural organization and splice variants of the POLE1 gene encoding the catalytic subunit of human DNA polymerase epsilon.

The catalytic subunit of human DNA polymerase epsilon, an enzyme involved in nuclear DNA replication and repair, is encoded by the POLE1 gene. This gene is composed of 51 exons spanning at least 97 kb of genomic DNA. It was found to encode three alternative mRNA splice variants that differ in their 5'-terminal sequences and in the N-termini of the predicted proteins. A CpG island covers the promoter region for the major transcript in HeLa cells. This promoter is TATA-less and contains several putative binding sites for transcription factors typical of S-phase-up-regulated and serum-responsive promoters. Potential promoter regions were also identified for the two other alternative transcripts. Interestingly, no nuclear polyadenylation signal sequence was detected in the 3'-untranslated region, although a poly(A) tail was present. These results suggest a complicated regulatory machinery for the expression of the human POLE1 gene, including three alternative transcripts expressed from three promoters.

3' Untranslated Regions↗
PubMed1999

An intramembrane modulator of the ErbB2 receptor tyrosine kinase that potentiates neuregulin signaling.

The ErbB2 receptor tyrosine kinase plays a critical role in a variety of developmental processes, and its aberrant activation may contribute to the progression of some breast and ovarian tumors. ASGP2, a transmembrane glycoprotein found on the surface of the highly metastatic ascites 13762 rat mammary adenocarcinoma cell line, is constitutively associated with ErbB2 in these cells and in mammary tissue from pregnant rats. Expression studies indicate that ASGP2 interacts directly and specifically with ErbB2 through one of its epidermal growth factor-like domains and that the co-expression of the two proteins in the same cell dramatically facilitates their direct stable interaction. Ectopic expression of ASGP2 in human melanoma tumor cells potentiates the response of endogenous ErbB2 to the neuregulin-1 growth factor. These observations point to a novel intramembrane mechanism for the modulation of receptor tyrosine kinase activity.

Animals↗
PubMed1999

Stoichiometrically bound beta-carotene in the cytochrome b6f complex of oxygenic photosynthesis protects against oxygen damage.

The cytochrome b6f complex of oxygenic photosynthesis carries out "dark reactions" of electron transfer that link the light-driven reactions of the reaction centers, and coupled proton transfer that generates part of the electrochemical potential utilized for ATP synthesis. In contrast to the bc1 complex of the respiratory chain, with which there are many structural and functional homologies, the b6f complex contains bound pigment molecules. Along with the specifically bound chlorophyll a previously found to be bound stoichiometrically in the dimeric b6f complex, it was found in the present study that beta-carotene is also present in the b6f complex at stoichiometric levels or nearly so. Chlorophyll and carotenoid pigments were quantitatively extracted from b6f complex purified from (i) the thermophilic cyanobacterium, Mastigocladus laminosus, (ii) spinach chloroplasts, and (iii) the green alga, Chlamydomonas reinhardtii. Visible and mass spectra showed the carotenoid to be a beta-carotene of molecular weight = 536, with a stoichiometry of 1. 0:1 relative to cytochrome f in the highly active M. laminosus complex but somewhat lower stoichiometries, 0.77 and 0.55, in the b6f complex obtained from spinach chloroplasts and C. reinhardtii. A photoprotective function for the beta-carotene was inferred from the findings that the rate of photobleaching of the chlorophyll a bound in the complex was found to vary inversely with beta-carotene content and to decrease markedly in the presence of ambient N2 instead of air. The presence of beta-carotene in the b6f complex, and not in the related bc1 complexes of the mitochondrial respiratory chain and photosynthetic bacteria, suggests that an additional function is to protect the protein complexes in oxygenic photosynthetic membranes against toxic effects of intramembrane singlet O2.

Animals↗
PubMed1999

The early molecular natural history of experimental osteoarthritis. I. Progressive discoordinate expression of aggrecan and type II procollagen messenger RNA in the articular cartilage of adult animals.

OBJECTIVE: To quantify changes in the chondrocyte metabolism of aggrecan core protein and type II procollagen messenger RNA (mRNA) during the early and middle phases of experimental osteoarthritis (OA) in animals. METHODS: Experimental OA was induced by transecting the cranial cruciate ligament of the stifle joint in adult animals; articular cartilage was harvested and analyzed after 4, 10, and 32 weeks. RESULTS: Northern blot analysis revealed no change in aggrecan mRNA 4 weeks after surgery compared with aggrecan mRNA in the unoperated contralateral control joints; aggrecan mRNA levels became significantly elevated by 10 and 32 weeks after surgery. In OA cartilage, type II procollagen mRNA was dramatically and progressively elevated at all times after surgery. The relative increases in type II procollagen mRNA exceeded the relative increases in aggrecan mRNA at all times after surgery, and these differences increased progressively over time. Articular chondrocytes became activated globally (total RNA increases) and specifically (mRNA increase) early after joint injury and remained activated throughout the early and middle phases of this experimental OA. CONCLUSION: The early natural history of experimental OA is characterized by a progressive imbalance in the mRNA expression of aggrecan and type II procollagen in articular chondrocytes. These results suggest that the stimuli for the transcription of these 2 genes are fundamentally different in this animal model.

Aggrecans↗
PubMed1999

A comparison of various "housekeeping" probes for northern analysis of normal and osteoarthritic articular cartilage RNA.

Several approaches are commonly used to normalize variations in RNA loading on Northern blots, including: ethidium bromide (EthBr) fluorescence of 18S or 28S rRNA or autoradiograms of radioactive probes hybridized with constitutively expressed RNAs such as elongation factor-1alpha (ELF), glyceraldehyde-3-phosphate dehydrogenase (G3PDH), actin, 18S or 28S rRNA, or others. However, in osteoarthritis (OA) the amount of total RNA changes significantly and none of these RNAs has been clearly demonstrated to be expressed at a constant level, so it is unclear if any of these approaches can be used reliably for normalizing RNA extracted from osteoarthritic cartilage. Total RNA was extracted from normal and osteoarthritic cartilage and assessed by EthBr fluorescence. RNA was then transferred to a nylon membrane hybridized with radioactive probes for ELF, G3PDH, Max, actin, and an oligo-dT probe. The autoradiographic signal across the six lanes of a gel was quantified by scanning densitometry. When compared on the basis of total RNA, the coefficient of variation was lowest for 28S ethidium bromide fluorescence and oligo-dT (approximately 7%), followed by 18S ethidium bromide fluorescence and G3PDH (approximately 13%). When these values were normalized to DNA concentration, the coefficient of variation exceeded 50% for all signals. Total RNA and the signals for 18S, 28S rRNA, and oligo-dT all correlated highly. These data indicate that osteoarthritic chondrocytes express similar ratios of mRNA to rRNA and mRNA to total RNA as do normal chondrocytes. Of all the "housekeeping" probes, G3PDH correlated best with the measurements of RNA. All of these "housekeeping" probes are expressed at greater levels by osteoarthritic chondrocytes when compared with normal chondrocytes. Thus, while G3PDH is satisfactory for evaluating the amount of RNA loaded, its level of expression is not the same in normal and osteoarthritic chondrocytes.

Actins↗
PubMed1999

[Effects of lovastatin on plasma lipid, plasma glucose and insulin metabolism of patients with type II B hyperlipemia].

This study was directed at the effects of lovastatin on plasma glucose and insulin metabolism of patients with Type II B hyperlipemia. Thirty patients with Type II B hyperlipemia were observed. At the beginning, We detected the patients' TC, TG, HDL-C, VLDL-C with enzyme assay, calculated their LDL-C with formula, determined their plasmaglucose(PG) with oxidase assay and plasma insulin(PI) with immunoradioassay, and then we performed OGTT and insulin release test, these indices were detected again after the administration of 8 weeks' lovastatin therapy (20 mg per day). The results showed that, aftert the therapy, TC and LDL-C decreased significantly(P < 0.05), TG, HDL-C and VLDL-C had no significant change(P > 0.05). Fasting plasma glucose(FPG) and fasting plasma insulin(FPI) increased (the former, P < 0.05). Two hours after administration of glucose, the level of plasma glucose(2hPG) and plasma insulin(2hPI)increased(the latter, P < 0.05). 1/(FPG x FPI) had no significant change, but 1/(2hPG x 2hPI) decreased (P < 0.05). These data indicate that long-period use of lavastatin may cause insulin resistance. So we advise patients with Type II B hyperlipemia treated by statin to limit their glucose intake in case of hyperinsulinemia and insulin resistance.

Aged↗
PubMed1999

[Observation on efficacy of artemether compound against vivax malaria].

AIM: To observe the efficacy of artemether compound against vivax malaria. METHODS: Each artemether compound tablet contains 120 mg benflumetolum and 20 mg artemether. 132 patients with vivax malaria were divided into 3 groups. Group A, 36 patients received 8 tablets as an initial dose, followed by 4 tablets daily for 2 days; group B, 41 patients received 8 tablets as an initial dose, followed by 3 tablets daily for 4 days; group C, 55 patients receiving chloroguine-primaquine served as control. Two patients of group A were voluntarily to be bitten by Anopheles dirus before and after medication to observe the influence of artemether compound on the sporogony. RESULTS: The average defervescence times for groups A, B and C were 22.3 h, 23.2 h and 25.0 h (P > 0.05), respectively, the average parasite clearance times were 33.5 h, 30.5 h and 44.9 h, respectively, the average parasite clearance times of groups A and B were all significantly shorter than that of group C (P < 0.01). The replase rates of groups A, B and C were 84.9%, 78.8% and 22.9%, respectively, followed-up at nine months, the relapse rates of groups A and B were higher than that of group C(P < 0.01). CONCLUSION: Two regimens of artemether compound have the advantage of high efficacy against vivax malaria.

Adolescent↗