Biomedical subjects

Q Ding

Publications and source records attributed to Q Ding.

At least 55 records · Page 3Linked to original sources

PubMed1997

Sex hormones and renal nitric oxide synthases.

The present study was undertaken to determine whether sex hormones influence nitric oxide synthase levels in the kidney. Five groups of rats were studied: males, castrated males, females, oophorectomized females, and oophorectomized females receiving estradiol replacement therapy. Endothelial nitric oxide synthase (eNOS) levels in the kidney were measured by Western blotting. eNOS levels were significantly greater in the renal medulla of female rats compared with male rats (3545 +/- 473 versus 2418 +/- 205 densitometry units (DU), P < 0.05). Oophorectomy reduced renal medullary eNOS levels to that of intact male rats (2566 +/- 304 DU, P = NS). Estrogen replacement therapy significantly increased medullary eNOS levels in oophorectomized animals (3249 +/- 377 versus 2302 +/- 213 DU, P < 0.05). Renal inducible nitric oxide synthase (iNOS) levels were measured after induction with lipopolysaccharide. iNOS levels were significantly greater in the renal medulla of female rats compared with male rats (677 +/- 253 versus 252 +/- 12 DU, P < 0.05). Oophorectomy reduced renal medullary iNOS levels to that of intact male rats (295 +/- 57 DU, P = NS). In contrast, estrogen replacement therapy significantly increased medullary iNOS levels in oophorectomized animals (682 +/- 356 versus 160 +/- 92 DU, P < 0.05). Steady-state levels of mRNA for iNOS were found to be higher in the inner medulla of female rats compared with male rats (1519 +/- 211 versus 899 +/- 105 DU, P < 0.05). In contrast to these findings, sex hormones failed to influence nitric oxide production or iNOS levels in lipopolysaccharide-stimulated mesangial cells in culture. These results suggest that gender may influence renal medullary synthesis of nitric oxide.

Animals↗

PubMed1997

[Expression of P21, p53 and proliferating cell nuclear antigen in human bladder cancer].

OBJECTIVE: To study the expression of cancer gene product and anti-cancer gene product in the same bladder cancer. METHODS: Immunohistochemical staining was used to determine the expression of P21, p53 and proliferating cell nuclear antigen (PCNA) in 5 normal bladder tissues and 58 bladder cancers. RESULTS: No P21, p53 and PCNA were expressed in the 5 normal bladder tissue samples. The positive incidence of P21, p53 and PCAN expression in the bladder cancers were 62.1%, 55.2% and 58.6% respectively. p53 and PCNA were located in cell nuclei and P21 located on the cell membrane in bladder cancer. The expression of P21, p53 and PCNA correlated to the stage, clinical grade and patient survival rates of this tumor. CONCLUSION: These results suggest that P21, p53 and PCNA immunolabelling may be used to determine the prognosis of bladder cancer patients.

Carcinoma, Transitional Cell↗

PubMed1997

[Cloning and permanent expression in eukaryotic cells of rhTpo].

OBJECTIVE: To obtain recombinant human thrombopoietin (rhTpo). METHODS: rhTpo gene was cloned from fetal liver mRNA by means of RT-PCR and subcloned into permanent expressing plasmid RC/CMV in order to form a recombinant permanent expressing plasmid RC/CMV/Tpo. RESULTS AND CONCLUSION: After being transferred into CHO cells, the eukaryotic permanent expression of rhTpo, which can enhance murine megakaryocyte colony growth in vitro, was obtained.

Animals↗

PubMed1997

[Studies on selectivity of recognizing factor for rmf promoter].

The truncted DNA template carrying rmf gene promoter was transcripted by E. coli RNA polymorase holoenzyme (E sigma) reconstituted with core enzyme (alpha 2 beta beta') and sigma 70 or sigma 38 in vitro. The initional site of the transcription of rmf was confirmed with different restriction endonuclease. rmf promoter can be recognized by E sigma 70 but not E sigma 38. The suitable temperature for in vitro transcription was 37 degrees C, NaCl concentration was 50 mmol/L.

DNA-Directed RNA Polymerases↗

PubMed1996

Immunolocalization of FGF-1 and receptors in human renal allograft vasculopathy associated with chronic rejection.

Despite recognition of chronic vasculo-occlusive disease in solid organ transplantation, the exact pathophysiologic events resulting in neointima formation remain to be elucidated. Since acidic fibroblast growth factor (FGF-1) is an established modulator of vascular cell function, we examined the expression of this growth factor and its high affinity receptors in both relevant renal transplant controls (n = 5) and tissue from patients (n = 19) who underwent nephrectomy following graft loss secondary to chronic rejection. In situ hybridization and immunohistochemical studies demonstrated minimal vascular expression and distribution of FGF-1 and FGF high affinity receptors in the normal human kidney. In contrast, vascular lesions in kidney allografts experiencing chronic rejection demonstrated the exaggerated appearance of FGF-1 ligand and receptors. Immunoreactive FGF-1 readily was detected in medial smooth muscle cells and focal areas of intimal hyperplasia, particularly in association with the presence of inflammatory infiltrate. Enhanced staining for FGF-1 mRNA primarily was associated with the appearance of resident inflammatory cells. Medial smooth muscle cells of hyperplastic vascular structures demonstrated the greatest immunoappearance of FGF receptors-however, diffuse immunostaining also was observed in areas of intimal hyperplasia. The enhanced appearance of both FGF-1 and FGF receptors in the vascular wall suggests that this polypeptide mitogen may serve as an important mediator of growth responses associated with neointima development and angiogenesis during chronic rejection of human renal allografts.

Adult↗

PubMed1996

Immunolocalization of FGF-1 and receptors in glomerular lesions associated with chronic human renal allograft rejection.

Glomerular lesions are considered one of the more detrimental pathologic changes associated with chronic rejection of renal allografts. To elucidate potential pathophysiologic mechanisms associated with transplant glomerulopathy, we examined the expression of acidic fibroblast growth factor (FGF-1) and its high-affinity receptors (FGFR) in both relevant renal transplant controls (n=5) and tissue from patients (n=19) who underwent nephrectomy following graft loss secondary to chronic rejection. In situ immunohistochemical analyses demonstrated minimal staining and distribution of FGFR and FGF-1, which was localized to the mesangial matrix in glomeruli from normal human kidneys. In situ hybridization failed to detect the presence of FGF-1 mRNA in control tissue. In contrast, each stage of the developing glomerular lesion associated with chronic rejection demonstrated the exaggerated appearance of FGF-1 protein in visceral and parietal epithelial cells. Intense staining for FGF-1 protein did not correlate with the increased appearance of FGF-1 mRNA, which was restricted to circulating inflammatory cells. Glomeruli in kidneys with findings of chronic rejection also exhibited increased immunodetection of both FGFR and PCNA in mesangial and epithelial cells. Immunogold labeling of chronically rejected visceral epithelial cells revealed both cytoplasmic and nuclear/localization of FGF-1, thereby establishing mitogenic potential of the growth factor. The enhanced appearance of both biologically active FGF-1 and FGFR suggests that this polypeptide may serve as an important mediator of growth responses associated with glomerular lesion development during chronic rejection.

Adolescent↗

PubMed1996

Promoter selectivity of Escherichia coli RNA polymerase E sigma 70 and E sigma 38 holoenzymes. Effect of DNA supercoiling.

The functional specificity was compared between two sigma factors, sigma 70 (the major sigma at exponentially growing phase) and sigma 38 (the essential sigma at stationary growth phase), of Escherichia coli RNA polymerase. The core enzyme binding affinity of sigma 38 was less than half the level of sigma 70 as measured by gel filtration column chromatography or by titrating the concentration of sigma required for the maximum transcription in the presence of a fixed amount of core enzyme. In addition, the holoenzyme concentration required for the maximum transcription of a fixed amount of templates was higher for E sigma 38 than E sigma 70. The transcription by E sigma 38 was, however, enhanced with the use of templates with low superhelical density, in good agreement with the decrease in DNA superhelicity in the stationary growth phase. We thus propose that the selective transcription of stationary-specific genes by E sigma 38 holoenzyme requires either a specific reaction condition(s) or a specific factor(s) such as template DNA with low superhelical density.

DNA, Superhelical↗

PubMed1996

Effects of sex hormones on mesangial cell proliferation and collagen synthesis.

In a variety of renal diseases, males progress at a more rapid rate and have a more fulminant course than females. This gender difference may be related to the direct effects of sex hormones on the cells of the kidney. To evaluate this hypothesis, we studied the effects of estrogens and testosterone on mesangial cell proliferation and collagen synthesis. At 48 hours, estradiol at 10 nM and 100 nM had a modest proliferative effect on cultured mesangial cells, as measured by 3H thymidine incorporation into DNA and direct cell counting. This estradiol effect was fully reversed by Tamoxifen (1 microM). Estradiol had no effect on cellular proliferation at 1 microM concentrations, but suppressed proliferation at 10 microM doses. Testosterone had a modest but statistically insignificant effect on proliferation at 10 nM and 100 nM concentrations but no effect at 1 microM or 10 microM. Neither estradiol nor testosterone at 10 microM affected total cellular protein accumulation. Estradiol at 1 microM and 10 microM, markedly suppressed total collagen synthesis as measured by 3H proline incorporation, and specifically suppressed the synthesis of collagen types I and IV, as measured by immunoprecipitation and gel electrophoresis. Testosterone did not affect collagen synthesis. Estradiol also reduced the steady state message for the alpha 2 chain of type I collagen, while testosterone had no effect. Neither estradiol nor testosterone affected the steady state message for TGF beta or EGF. The direct effects of estradiol on mesangial cell collagen generation may help explain the slower development of glomerulosclerosis in women and therefore the "protective" effect of female gender on the progression of renal disease.

Animals↗

PubMed1996

Studies on the transfer techniques of three maize genes.

Maize transformation has been carried out through microprojectile bombardment, ultrasonication in a DNA buffer, and ovary-injection with a self-made microinjector. The plasmid pB48.415, which carries a 3'-truncated Bt-toxin protein gene and a hygromycin phosphotransferase (hpt) gene, was used in the transformation. Transgenic maize plants were obtained from immature embryos and embryogenic calli bombarded with a particle gun, embryogenic calli ultrasonicated under different conditions of ovaries injected 10-20 hours after pollination. The results of Dot blotting and Southern blotting analyses proved the integration of the Bt gene into maize genome.

Bacillus thuringiensis Toxins↗

PubMed1996

[Role of PCR and dot bolt hybridization in the detection of human papillomavirus of the penile cancer].

Human papillomavirus (HPV), a oncogenicpotential, may be carcinogenic effectors in variety of genital tract malignancies. We examined the association of human papillomavirus type 16 and 18 in 28 penile cancers by the highly sensitive polymerase chain reaction and dot bolt hybridization. Human papillomavirus type 16 was found in 14 of 28 penile cancers (50%), whereas type 18 was identified in 3 of 28 penile cancers (10.6%). Our results suggest humanpapillomavirus type 16 may play a role in the development of this tumor and associate with smoking and ages of patients.

Adult↗

PubMed1996

[Studies on modulation and control sigma 38 and RMF for the expression of some genes].

The E. coli mutants and wild type strains of rpoS and rmf were cultured in rich medium LB and limited component medium EP respectively. During the stationary phase, the viable cells of mutants were less than wild type strains's. The change of the product of serial proteins was quantified with Western blot. Sigma 38 has not effects on the product of rpoA, rpoB, rpoC, groE and tu gene, depress the transcription of crp and promote the expression of rmf. RMF can promote expression of rpoA, rpoD, groEl, rho, ompA and tufA gene in rich medium, but not in limited medium, and then depress and promote the expression of crp and rpoS respectively.

Bacterial Proteins↗

PubMed1995

Comparison of the allatostatin neuropeptide precursors in the distantly related cockroaches Periplaneta americana and Diploptera punctata.

Allatostatins are a family of insect neuropeptides that inhibit juvenile hormone biosynthesis by the corpora allata. We have characterized cDNA and genomic DNA sequences that specify a preproallatostatin precursor in the oviparous cockroach Periplaneta americana. Comparison of this precursor with that previously described [Donly, B. C., Ding, Q., Tobe, S. S. & Bendena, W. G. (1993) Proc. Natl Acad. Sci. USA 90, 8807-8811] for the viviparous cockroach Diploptera punctata revealed several common features. First, the precursors are remarkably similar in size and the organization of the peptides within the precursor is conserved. The separation of the peptides into groups by acidic domains within the precursor has been maintained. The P. americana precursor contains 14 allatostatin-like peptides that contain the core C-terminal sequence (Tyr/Phe)-Xaa-Phe-Gly-(Leu/Ile)-NH2, as compared to the D. punctata precursor, which contains 13. Five of the peptides are perfectly conserved between the two species. The remainder, with one exception, contain amino acid substitutions in the N-terminal address portion of the peptide. Several features of expression are also similar between these two species. In both, a single copy gene specifies a large allatostatin transcript of 5.0 kb in P. americana and 9.2 kb in D. punctata. In P. americana, allatostatin transcripts appear to be produced by numerous cells in different regions of the brain.

Amino Acid Sequence↗

PubMed1995

Promoter selectivity control of Escherichia coli RNA polymerase by ionic strength: differential recognition of osmoregulated promoters by E sigma D and E sigma S holoenzymes.

Transcription in vitro of two osmoregulated promoters, for the Escherichia coli osmB and osmY genes, was analysed using two species of RNA polymerase holoenzyme reconstituted from purified core enzyme and either sigma D (sigma 70, the major sigma in exponentially growing cells) or sigma S (sigma 38, the principal sigma at stationary growth phase). Under conditions of low ionic strength, the osmB and osmY promoters were transcribed by both E sigma D and E sigma S. Addition of up to 400 mM potassium glutamate (K glutamate), mimicking the intracellular ionic conditions under hyperosmotic stress, specifically enhanced transcription at these promoters by E sigma S but inhibited that by E sigma D. At similar high concentrations of potassium chloride (KCl), however, initiation at both these promoters was virtually undetectable. These data suggest that the RNA polymerase, E sigma S, itself can sense osmotic stress by responding to changes in intracellular K glutamate concentrations and altering its promoter selectivity in order to recognize certain osmoregulated promoters.

DNA-Directed RNA Polymerases↗

PubMed1995

[The study of p53 gene mutation in human bladder cancer].

Alteration of p53 gene and the molecular biological difference between superficial and invasive bladder cancer were investigated by polymerase chain reaction-single strand conformation polymorphism analysis and direct sequencing technique. p53 gene mutations were examined in exon region 5 to 8 in 21 bladder cancers. Only one of 14 superficial bladder cancers was found to have p53 gene mutation. Four of 7 invasive bladder cancers with T2, T3 and T4 were found to have p53 gene mutation. p53 gene mutation was found none of the 4 cancers with grade 1, only one of cancers with grade 2, four of 12 cancers with grade 3. These results suggest that p53 gene play an important role in the development of human bladder cancer.

Carcinoma, Transitional Cell↗

PubMed1993

Molecular cloning of the gene for the allatostatin family of neuropeptides from the cockroach Diploptera punctata.

Allatostatins (ASTs) are insect neuropeptides that inhibit juvenile hormone biosynthesis by the corpora allata. We have isolated a cDNA from the cockroach Diploptera punctata that encodes a 41.5-kDa precursor polypeptide containing the AST family of peptides. Translation of the cDNA revealed a 370-amino acid pre-pro-peptide consisting of 13 AST-type peptides and appropriate processing sites for endoproteolytic cleavage and amidation. The 13 potential AST sequences are characterized by the C-terminal AST corestructure Phe-Gly-Leu-NH2, with only one exception. Separating the clustered ASTs in the precursor, three acidic spacer regions are found. Contained within the largest of these are two potentially related peptides that may also be processed. Southern blot analysis revealed the presence of a single copy of the AST gene per haploid genome, as well as the probability that the gene may be present in at least two allelic forms. In situ hybridization indicated the AST-encoding gene is expressed in neurosecretory cells of D. punctata brain.

Amino Acid Sequence↗

PubMed1993

CSF cholinesterase in early-onset and late-onset Alzheimer's disease and multi-infarct dementia of Chinese patients.

Using Ellman spectrophotometric method we measured the total cholinesterase (ChE) activity in lumbar cerebrospinal fluid (CSF) of 13 persons without neurological disorder, 10 non-demented patients with cerebral infarcts, 17 patients with dementia of Alzheimer's type (DAT) (11 presenile, 6 senile cases), 10 patients with multi-infarct dementia (MID), 1 patient with Parkinson's disease associated with dementia. The ChE activity in CSF was significantly lower in the DAT group compared with age-matched control subjects (p < 0.001). This paper also analyses the possibility of using CSF ChE activity as a marker of DAT, and the relationships between its level of activity and the age of the patient at onset, stage of illness and severity of dementia as well as discrepancies in the data published so far. Previous work has shown that ChE activity in the brain tissue and CSF of MID is normal: therefore, if low ChE activity is found in the CSF of MID patients, as was obtained in 8 out of 10 cases in our series, the diagnosis of mixed dementia should be considered.

Aged↗

PubMed1992

[Clinical study of qianxining in the treatment of 60 cases of yang hyperactivity due to yin deficiency type of hypertension].

60 cases with Yang Hyperactivity due to Yin Deficiency type of hypertension were randomly divided into two groups. One was treated with TCM and the other with WM as control. The results showed that: (1) there were no significant differences in the total effective rate and the amplitude of lowering of blood pressure between two groups; (2) the improvement of symptoms and disturbance of autonomic nerve was significant in TCM group in comparison with control; (3) there were some changes in HR, SV, plasma PRA, TXB2 and 6-keto-PGF1 alpha level in both groups, but the decrease of TXB2/6-keto-PGF1 alpha ratio was significant in TCM group only (P < 0.05); (4) TC and TG in patients with hyperlipemia showed a remarkable drop in TCM group (P < 0.02; P < 0.005). All these revealed that Qianxining was a satisfactory hypotensive remedy and a further exploration of its mechanism is suggested.

6-Ketoprostaglandin F1 alpha↗

PubMed1990

[Effects of hand electroacupuncture on the mean value of cAMP content and Na(+)-K(+)-ATPase activity in the tissue of various areas of the rat brain].

The results showed that the mean value of cAMP content in rats endbrain treated by electroacupuncture was obviously reduced than control group. The content of cAMP in the diencephalon and brain stem, the activity of Na(+)-K(+)-ATPase in the whole brain were raised and they show the positive relation with the excite intensity respectively. These experimental results might be taken as a basis for using the hand electroacupuncture for treatment of schizophrenia, manic state and depressive state. This experiment showed the treatment mechanisms of the hand electroacupuncture in accordance with ECT therapy.

Animals↗