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Biomedical subjects

Q Zheng

Publications and source records attributed to Q Zheng.

At least 55 records · Page 3Linked to original sources
PubMed2000

Development of a quality control material for the measurement of 8-oxo-7,8-dihydro-2'-deoxyguanosine, an in vivo marker of oxidative stress, and comparison of results from different laboratories.

The measurement of 8-oxo-7,8-dihydro-2'-deoxyguanosine is an increasingly popular marker of in vivo oxidative damage to DNA. A random-sequence 21-mer oligonucleotide 5'-TCA GXC GTA CGT GAT CTC AGT-3' in which X was 8-oxo-guanine (8-oxo-G) was purified and accurate determination of the oxidised base was confirmed by a 32P-end labelling strategy. The lyophilised material was analysed for its absolute content of 8-oxo-dG by several major laboratories in Europe and one in Japan. Most laboratories using HPLC-ECD underestimated, while GC-MS-SIM overestimated the level of the lesion. HPLC-ECD measured the target value with greatest accuracy. The results also suggest that none of the procedures can accurately quantitate levels of 1 in 10(6) 8-oxo-(d)G in DNA.

Biomarkers↗
PubMed2000

[Action of fengsuidan granules on experimental anti-oral ulcer].

OBJECTIVE: To explore the anti-oral ulcer action, anti-inflammatory and analgesic effect of Fengsuidan Granules(FSDG). METHODS: FSDG(0.5, 5.0, 10.0 g.kg-1) were administered to experimental animals. The oral ulcer in experimental animals was effected by means of white staphylococcus (sc) and carbolic acid (buming). RESULTS: Such as acetic acid body turning, hot-plate, auricle inflammation by dimethylbenzene and foot swelling by egg white were used. CONCLUSION: Following certain regularities of dose-effect relationship, FSDG has anti-oral ulcer effect, helps reduce and heal the ulcer and works efficaciously in analgesic and anti-inflammatory cases.

Animals↗
PubMed2000

[Characterization of the Pt/CeO2-ZrO2/Al2O3 catalysts by spectra].

The performance of Pt/Al2O3 catalysts with CeO2-ZrO2 in difference ways was studied by NIR-FT-Raman, BET, H2 chemisorption, XRD. It shows that the dispersion of Pt on Al2O3 is improved with the increasing of dispersion of CeO2-ZrO2 on the surface of Al2O3, owing to the strong interacting between CeO2-ZrO2 and Pt. And adding with salts is priority.

Aluminum Oxide↗
PubMed1999

Alterations of the actin polymerization status as an apoptotic morphological effector in HL-60 cells.

The alterations of the cytoskeletal actin network have been implicated as a morphological effector in apoptosis. However, studies directly linking actin change to the morphological events in apoptosis are lacking. This study quantitatively examined the effect of actin alteration on the camptothecin (CPT)-induced apoptotic process in HL-60 cells. Actin alteration was induced by two distinctive types of agent: the polymerization-stimulating agent, Jasplakinolide (Jas), and the polymerization-blocking agent, cytochalasin B (CB). The actin polymerization status was measured by two complementary methods: the cell pellet-based DNase I inhibition method, and the individual cell-based quantitative fluorescence image analysis (QFIA) assay. Actin polymerization induced by Jas caused apoptosis directly. By contrast, CB, an actin polymerization-blocking agent, partially inhibited CPT-induced apoptosis. A similar inhibition of the CPT-induced apoptosis response was observed with a more specific actin depolymerization agent, cytochalasin E. The alterations of the actin polymerization status occurred in three sequential steps during the apoptotic process: first polymerization, followed by depolymerization, and finally degradation. However, compared with CPT-induced apoptosis, Jas-induced apoptosis was characterized by pronounced actin polymerization that corresponded morphologically with prominent membrane blebbing, but less apoptotic body formation. Furthermore, DNase I activity, which is normally inhibited by G-actin, was specifically detected in Jas-treated cells. These results show that the regulation of actin polymerization is an important apoptotic morphological effector, whereas the alterations of the actin polymerization status by chemicals have profound effects not only on altering the morphology of apoptotic cells, but on apoptosis induction in HL-60 cells as well.

Actins↗
PubMed1999

Isolation, characterization, and mapping of a zinc finger gene, ZFP95, containing both a SCAN box and an alternatively spliced KRAB A domain.

A new zinc finger gene of the Krüppel family was identified by screening a human fetal cartilage cDNA library with degenerate oligonucleotides. Sequence analysis indicates that ZFP95 contains 12 highly conserved zinc finger motifs at the C-terminus and a SCAN box as well as a KRAB A domain at the N-terminus of the protein. ZFP95 represents a member of a new subclass of Krüppel zinc finger proteins containing both a SCAN box and a KRAB domain. Sequence comparison revealed that ZFP95 is the human ortholog of murine Zfp95, which is differentially expressed during spermatogenesis. We demonstrate that ZFP95 is ubiquitously expressed in adult and fetal tissues with the strongest expression in testis. Two transcripts, 4. 2 and 4.6 kb, were detected in all tissues tested. In testis, a third transcript of 3.8 kb was present. RT-PCR analysis confirmed alternative splicing for the KRAB A domain and an upstream exon leading to three transcripts of ZFP95 with and without this transcriptional repressor domain. Finally, we show that ZFP95 maps on human chromosome 7q22 between the markers D7S651 and WI-5853.

Adult↗
PubMed1999

Marked temperature dependence of the platelet calcium signal induced by human von Willebrand factor.

Interaction of von Willebrand factor (vWF) with the platelet is essential to hemostasis when vascular injury occurs. This interaction elevates the intracellular free calcium concentration ([Ca2+]i) and promotes platelet activation. The present study investigated the temperature dependence of vWF-induced [Ca2+]i signaling in human platelets. The influence of temperature can provide invaluable insight into the underlying mechanism. Platelet [Ca2+]i was monitored with Fura-PE3. Ristocetin-mediated binding of vWF induced a transient platelet [Ca2+]i increase at 37 degrees C, but no response at lower temperatures (20 degrees C to 25 degrees C). This temperature dependence could not be attributed to a reduction in vWF binding, as ristocetin-mediated platelet aggregation and agglutination were essentially unaffected by temperature. Most other platelet agonists (U-46619, alpha-thrombin, and adenosine 5'-diphosphate [ADP]) induced a [Ca2+]i signal whose amplitude did not diminish at lower temperatures. The [Ca2+]i signal in response to arachidonic acid, however, showed similar temperature dependence to that seen with vWF. Assessment of thromboxane A2 production showed a strong temperature dependence for metabolism of arachidonic acid by the cyclo-oxygenase pathway. vWF induced thromboxane A2 production in the platelet. Aspirin treatment abolished the vWF-induced [Ca2+]i signal. These observations suggest that release of arachidonic acid and its conversion to thromboxane A2 play a central role in vWF-mediated [Ca2+]i signaling in the platelet at physiological temperatures.

Blood Platelets↗
PubMed1999

Discrepancies in the measurement of UVC-induced 8-oxo-2'-deoxyguanosine: implications for the analysis of oxidative DNA damage.

Ultraviolet (UV) light-induced indirect, oxidative damage to DNA has received increasing attention with respect to the mutagenic and carcinogenic effects of solar radiation. An oxidative lesion that has raised particular interest because of its qualitative and quantitative importance is 8-oxo-2'-deoxyguanosine. This deoxynucleoside lesion is most frequently measured by high performance liquid chromatography with electrochemical detection (HPLC-EC) following enzymatic hydrolysis of DNA or as the base equivalent, 8-oxoguanine, by gas chromatography-mass spectrometry (GC-MS) following acid hydrolysis of DNA. We have noted a discrepancy in the literature whereby the levels of 8-oxo-2'-deoxyguanosine measured by HPLC-EC in UVC-irradiated DNA are significantly higher than when 8-oxoguanine is measured by GC-MS. By making use of the availability of both HPLC-EC and stable-isotope dilution GC-MS methodologies in our laboratory we have confirmed the discrepancy noted in the literature by parallel analysis of the same UVC-irradiated calf thymus DNA samples. Furthermore, analysis of the UVC-induced product by UV-visible spectrophotometry, voltammetry and its detection by a monoclonal antibody which recognises 8-oxo-2'-deoxyguanosine strongly suggests that the product is indeed 8-oxo-2'-deoxyguanosine. Partial explanation for this discrepancy could be an inordinate resistance of UVC-irradiated DNA to formic acid hydrolysis. However, we cannot completely exclude the possibility that there is a formic acid-labile species which co-elutes with 8-oxo-2'-deoxyguanosine in enzymatically digested UVC-irradiated DNA. Whether this phenomenon is unique to UV-irradiation damage or occurs with other systems that cause oxidative damage to DNA awaits further investigation. Irrespective of the exact mechanism, there will be significant implications for the analysis of oxidative DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

[A DNA probe suitable for the detection of chromosome 21 copy number in human interphase nuclei by fluorescence in situ hybridization].

OBJECTIVE: To prepare DNA probe which can be used to accurately detect chromosome 21 copy number in human interphase nuclei by fluorescence in situ hybridization (FISH). METHODS: A probe was produced by universal primer PCR from YAC clone 881D2 and characterized by FISH to metaphases and interphase nuclei of peripheral lymphocytes from 8 normal individuals and 5 patients suffering from trisomy 21. RESULTS: A DNA probe was produced and its characteristics were :(1) Most of the probes ranged in size from 350bp to 750bp; (2) The hybridization signals of the probes were located near centromere on long arm of human chromosome 21; (3) In 1524 metaphases scored, about 99.95% of hybridization signals were located on chromosome 21; (4) The signals were very bright and recognizable easily in both metaphases and interphases nuclei; (5) The expected copy number of chromosome 21 was detected by FISH with the probe in more than 98.40% of interphase nuclei and 99.60% of metaphases. CONCLUSION: The DNA probe reported here is suitable for the detection of chromosome 21 copy number in interphase nuclei and for the study of segregation of chromosome 21 during mitoses of human lymphocytes in culture.

Cell Nucleus↗
PubMed1999

The experimental study on mixed culture of osteoblasts and tricalcium phosphate ceramics in vitro.

To study the effects of tricalcium phosphate (TCP) ceramics on osteoblasts, the rat osteoblasts were cultured with the TCP ceramics in vitro. Scanning electron microscopy and the colorimetric methyl-thiazol-tetrazolium assay showed that the osteoblasts could adhere well to the surface of the ceramics and the culture dish, and the proliferation of the cells was not inhibited. The results demonstrated that TCP ceramics possessed an excellent cytocompatibility with the osteoblasts, and had some promoting effects on proliferation of osteoblasts.

Animals↗
PubMed1999

Androgen receptor gene CAG repeat length varies in a race-specific fashion in men without prostate cancer.

OBJECTIVES: Preliminary studies suggest that black men have shorter androgen receptor CAG repeat length compared with non-Hispanic whites. Because decreased CAG repeat length (in particular less than 20 repeats) may be associated with increased prostate cancer risk, these findings are potentially important in providing a hypothesis to explain the increased risk of prostate cancer in black men. METHODS: CAG repeat length in the androgen receptor (exon one) was determined by a polymerase chain reaction method in 130 non-Hispanic white and 65 black men. All men had prostate-specific antigen levels less than 4 ng/mL and normal digital rectal examinations. Men self-classified themselves into racial categories by a standardized questionnaire. RESULTS: For whites, the mean +/- SD, median, and range of CAG repeat length were 21.0+/-3.0, 21, and 9 to 28, respectively. For blacks, the mean +/- SD, median, and range of CAG repeat length were 19.0+/-3.0, 19, and 13 to 26, respectively. The mean and median CAG repeat length in blacks were statistically significantly shorter than in whites. Black men were twice as likely as whites to have fewer than 20 CAG repeats (56.9% versus 28.5%, P = 0.0001). CONCLUSIONS: These data unequivocally demonstrate that androgen receptor gene CAG repeat length varies in a race-specific manner in men without evidence of prostate cancer.

Black People↗
PubMed1999

A genetic screen for modifiers of drosophila Src42A identifies mutations in Egfr, rolled and a novel signaling gene.

Drosophila Src42A, a close relative of the vertebrate c-Src, has been implicated in the Ras-Mapk signaling cascade. An allele of Src42A, Su(Raf)1, dominantly suppresses the lethality of partial loss-of-function Raf mutations. To isolate genes involved in the same pathway where Src42A functions, we carried out genetic screens for dominant suppressor mutations that prevented Su(Raf)1 from suppressing Raf. Thirty-six mutations representing at least five genetic loci were recovered from the second chromosome. These are Drosophila EGF Receptor (Egfr), rolled, Src42A, and two other new loci, one of which was named semang (sag). During embryogenesis, sag affects the development of the head, tail, and tracheal branches, suggesting that it participates in the pathways of Torso and DFGF-R1 receptor tyrosine kinases. sag also disrupts the embryonic peripheral nervous system. During the development of imaginal discs, sag affects two processes known to require Egfr signaling: the recruitment of photoreceptor cells and wing vein formation. Thus sag functions in several receptor tyrosine kinase (RTK)-mediated processes. In addition, sag dominantly enhances the phenotypes associated with loss-of-function Raf and rl, but suppresses those of activated Ras1(V12) mutation. This work provides the first genetic evidence that both Src42A and sag are modulators of RTK signaling.

Animals↗
PubMed1999

Flow cytometric analysis of BHRF1 expression prohibiting apoptosis induced by radiation.

The Epstein-Barr virus gene BHRFI has homology with proto-oncogene bcl-2, which can protect cells from apoptosis. In order to investigate the effect of BHRF1 expression on the anti-apoptotic ability of nasopharyngeal carcinoma (NPC) cells after irradiation, a high-BHRF1 expression vector was constructed and transfected into the NPC cell line CNE2. Then, the alteration of proliferation and apoptosis in the cells was tested by flow cytometry after cobalt 60 irradiation. The results showed that BHRF1 expression could increase G1 delay and decrease the cell percentage in S phase before irradiation, and reduce the apoptotic rate of CNE2 cells and increase the cell percentage in S phase after irradiation. The results suggest that BHRF1 expression is able to alter the cell cycle and protect CNE2 cells from apoptosis induced by radiation.

Apoptosis↗
PubMed1999

Haematology and serum chemistry parameters of the pregnant rat.

This study describes the baseline haematology and serum chemistry values found in non-pregnant, pregnant (gestational days [GD] 2-21) and lactating (postnatal days 1-9) Sprague Dawley rats (n = 3-10/day) from the NCTR breeding colony of Crl:COBS CD(SD)BR strain. Maternal body weights on GD0 ranged from 250 to 300 g. Multiple analytes were measured in both whole blood and serum of dams. Amniotic fluid, fetal serum, and postnatal pup serum analyte values were also acquired. Maternal blood was collected from the heart under subterminal carbon dioxide (CO2) anaesthesia. Most pregnant dam blood values were not appreciably different from values for non-pregnant dams until near term; near-term values for some analytes (red blood cells, haemoglobin, haematocrit, mean corpuscular haemoglobin concentration, alkaline phosphatase, albumin, total protein, glucose, total bilirubin, sodium, and chloride) decreased but returned to near-normal values soon after delivery. The most dramatic change was a three-fold elevation of serum triglyceride levels near term with a subsequent decrease at birth. Most serum chemistry analytes measured in progeny increased after birth except for alkaline phosphatase, calcium and potassium levels which decreased.

Amniotic Fluid↗
PubMed1999

Extraneural organ involvement in human rabies.

Human rabies is a fatal encephalomyelitis. After the development of the central nervous system infection, there is centrifugal spread of the rabies virus to extraneural (systemic) organs. With histochemical staining and localization of rabies virus antigen (RVA) with immunoperoxidase staining, we have examined tissue sections of organs from 14 postmortem pediatric and adult cases of human rabies acquired in Mexico and the People's Republic of China. RVA was found in nerve plexuses in multiple organs, including the gastrointestinal tract. RVA was observed in muscle fibers of the heart, tongue, and larynx. RVA frequently was observed in the adrenal medulla with an associated inflammatory reaction. Minor salivary glands of the tongue contained RVA and major salivary glands showed RVA in plexuses, but not in either acini or ducts. Epithelial cells of the tongue and taste buds were occasionally infected. RVA was observed in hair follicles of the skin and rarely in pancreatic islets. The infection of extraneural organs was sometimes, but not always, associated with an inflammatory reaction. These findings indicate that centrifugal spread of rabies virus to extraneural organs occurs frequently in human rabies.

Adolescent↗
PubMed1999

[Implementation of "four-early principle" to raise the successful rate in mass burn casualties].

OBJECTIVE: To evaluate the feasibility and result of "four-early principle" in the treatment of mass burn casualties. METHODS: During the last 12 years, a total of 155 burn patients were admitted in 18 groups, and the following principles were implemented; early rapid fluid resuscitation during shock stage for delayed resuscitation patients; early tracheostomy to assist air passage humidification and lavation for moderate and severe inhalation injury; planning escharectomy and grafting during shock stage in patients with extensive deep burns; emphasizing early stage enteral nutritional support. RESULTS: The successful rate of treatment was raised, and the incidence of complications decreased in mass casualties with serious burn after implementing early stage treatment principles. CONCLUSION: The application of "four-early principle" on the treatment of mass burn casualties is feasible and effective.

Adolescent↗
PubMed1999

[Protein tyrosine kinase activation in the repair of rat gastric mucosa after damage].

OBJECTIVE: To investigate the possible role of protein tyrosine kinase (PTK) and its effect on nuclear protein phosphorylation and activating protein 1 (AP-1) activity in the rat gastric epithelial restitution. METHODS: Rat gastric mucosae were damaged with 20 mmol/L Deoxysodium cholate (DOC). Mucosal scrapings from the oxyntic gland area were obtained 3 hours after damage. The cellular membrane and nuclear fractions were dissociated from the extraction of the mucosal scrapings to assay the activity of PTK and AP-1, and the phosphorylation of nuclear protein. Different blockers, including Tyrphostin-51 for PTK and PD098059 for mitogen-activated protein kinase kinase (MAPKK), were used to study the signaling control for a better understanding of the mechanisms of gastric reepithelium. RESULTS: 20 mmol/L DOC caused moderate damage in rat gastric mucosae. PTK activity 3 hours after damage was 1 time that of the primary level, while nuclear protein phosphorylation level was increased about 4 folds. Tyrphostin-51 and PD098059 inhibited such effects by 85.3% and 61.6%, respectively. AP-1 activity was also greatly elevated after gastric mucosal damage and the effect was attenuated by both Tyrpsotin-51 and PD098059. CONCLUSION: PTK activation improves the rat gastric mucosal repair ability in the early phase after damage through the promotion of nuclear protein phospharylation and the increase in AP-1 activity. The effect of PTK is greatly magnified when the signals fly into the cellular nuclea, mainly through MAPK pathway.

Animals↗
PubMed1999

[Chemical constituents of fruits of Gardenia sootepensis Hutch].

OBJECTIVE: To demonstrate the chemical constituents of the fruits of Gardenia sootepensis. METHOD: Column chromatographic technology was employed to separate the water soluble part, and the compounds obtained were elucidated by spectral and chemical analysis. RESULT: Ten compounds have been isolated, seven of which elucidated respectively as D-mannitol, beta-sitosterol, deacetylasperulosidic acid methyl ester, geniposidic acid, geniposide, scandoside methyl ester and dimeric molecule of quinide. CONCLUSION: All the compounds were obtained from this plant for the first time.

Drugs, Chinese Herbal↗