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Biomedical subjects

X Qiu

Publications and source records attributed to X Qiu.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Experience of endoscopic sinus operation on 74 cases].

OBJECTIVE: To improve the curative effect of endoscopic sinus operation. METHOD: The clinical data of nasal cavity and nasal sinus via endoscopic sinus operation on 74 cases (115 sides) were in summary. Of those 74 cases, 65 were followed-up over six mothes. RESULT: It showed that 44 cases were cured, 18 were improved, 3 were ineffective. The effective rate was 95.4%. The disappearance rate of four symptons-nasal obstruction, headache, purulent nasal discharge and loss of smelling was 95.2%, 92%, 66.7% and 42.5%, respectively. The serious operative complication was absent. CONCLUSION: It helped to raise thd effect of anesthetization to apply nasal cavity surface anesthesia, nerve block anesthesia. Paying attention to the distinguish of dissection label can help to decrease the occurance of the serious complication of the sinus ethmoidal operation. The operation which was alternatively conducted between endoscope and cavascope, according to the operation requirement, can be carried out more thoroughly and more safely. Cleaning the operation cavity after operation can promote healing.

Adult↗
PubMed1998

Role of p53 in aziridinylbenzoquinone-induced p21waf1 expression.

Quinones are the second largest family of anticancer drugs clinically used in the United States. However, their exact mode of action at the cellular and molecular level is not completely understood. We have shown earlier that the quinone 3,6-diaziridinyl-1,4-benzoquinone (DZQ) leads to the increased expression of p21waf1/cip1/sdi1 protein, an inhibitor of cyclin-dependent kinases. Because p21 has been established as an important negative regulator of the cell cycle, we further investigated the molecular basis of p21 induction by DZQ. Here we report that the induction of p21 by DZQ is regulated at the transcriptional level, and requires the activation of p53, a tumor suppressor protein. In cells that lack functional p53 protein, DZQ-mediated p21 induction is greatly diminished. However, the introduction of a wild type p53 gene into p53-negative cells restores the strong DZQ-inducibility of p21. Restoration of wild type p53 status in HL60 myeloid leukemia cells significantly increases the cells' sensitivity to the cytotoxic effects of DZQ. Thus, our results indicate that the p53-p21 pathway may play a central role in mediating the gene-regulatory and cytotoxic effects of aziridinylbenzoquinones.

Animals↗
PubMed1998

A model for the mechanism of human topoisomerase I.

The three-dimensional structure of a 70-kilodalton amino terminally truncated form of human topoisomerase I in complex with a 22-base pair duplex oligonucleotide, determined to a resolution of 2.8 angstroms, reveals all of the structural elements of the enzyme that contact DNA. The linker region that connects the central core of the enzyme to the carboxyl-terminal domain assumes a coiled-coil configuration and protrudes away from the remainder of the enzyme. The positively charged DNA-proximal surface of the linker makes only a few contacts with the DNA downstream of the cleavage site. In combination with the crystal structures of the reconstituted human topoisomerase I before and after DNA cleavage, this information suggests which amino acid residues are involved in catalyzing phosphodiester bond breakage and religation. The structures also lead to the proposal that the topoisomerization step occurs by a mechanism termed "controlled rotation."

Amino Acid Sequence↗
PubMed1998

[Determination of the polymorphism of DXS102 locus and its application in gene diagnosis].

OBJECTIVE: To determine the polymorphism of DXS102 and use it in gene diagnosis in hemophilia B. METHODS: Amp-FLP and linkage analysis on 234 chromosomes. RESULTS: Eight alleles were found at DXS102 locus. The number of AC dinucleotide repeats ranged from 13 to 21. And the observed heterozygosity, calculated heterozygosity and polymorphism information content(PIC) were 0.87, 0.80 and 0.80, respectively. It was noted that the difference of the allele frequencies of DXS102 in Chinese and European populations was significant. By using the linkage analysis of the DXS102 locus, a family with a hemophilia B patient receiving gene therapy in 1994 was analyzed and a carrier in that family was then detected. CONCLUSION: The polymorphism of DXS102 locus reveals significant difference between Chinese and European populations. DXS102 locus can be used as a promising marker for gene diagnosis in hemophilia B family.

Chromosome Mapping↗
PubMed1998

Antibodies against the GB virus C envelope 2 protein before liver transplantation protect against GB virus C de novo infection.

GB virus C (GBV-C) is a newly discovered RNA virus related to the Flaviviridae family. Although GBV-C is not yet associated with any cause of liver disease, a humoral immune response against the GBV-C envelope 2 (E2) protein has been observed. Therefore, we studied the prevalence and clinical relevance of GBV-C RNA and anti-E2 antibodies in patients undergoing orthotopic liver transplantation (OLT). In addition, we tested whether the prevalence of anti-E2 antibodies may protect against GBV-C infection. Of the 182 liver recipients included in this study, 117 of these were evaluated for GBV-C recurrence or de novo infection. GBV-C RNA was detected in sera or plasma using single-tube, reverse-transcriptase polymerase chain reaction, and anti-E2 antibody was detected by enzyme immunoassay (EIA). Cumulative patient and graft survival was tested by using Kaplan-Meier analysis. The independence of prognostic values was assessed by using Cox regression analysis. Before OLT, GBV-C RNA and anti-E2 were detected in 4.0% to 28.6% and 10.0% to 68.8%, respectively, of patients suffering from different forms of chronic liver diseases. GBV-C reinfection after OLT was determined in 85.7%. Of the patients without evidence of exposure to GBV-C before OLT, 30 of 65 (46.2%) became GBV-C RNA positive after OLT. None of the 38 patients who were anti-E2 antibody positive before OLT became GBV-C RNA positive after OLT. Neither patient nor graft survival was significantly affected by the presence of either GBV-C RNA or anti-E2 antibody before OLT. Our data indicate that 1) GBV-C RNA positive patients have a high risk of reinfection after OLT, and 2) the presence of anti-E2 antibodies before OLT is associated with an absence of GBV-C infection after OLT, which may indicate a protective role of anti-E2 antibodies.

Adult↗
PubMed1998

Determination and analysis of antigenic epitopes of prostate specific antigen (PSA) and human glandular kallikrein 2 (hK2) using synthetic peptides and computer modeling.

Prostate specific antigen (PSA) and human glandular kallikrein 2 (hK2), produced essentially by the prostate gland, are 237-amino acid monomeric proteins, with 79% identity in primary structure. Twenty-five anti-PSA monoclonal antibodies (Mabs) were studied for binding to a large array of synthetic linear peptides selected from computer models of PSA and hK2, as well as to biotinylated peptides covering the entire PSA sequence. Sixteen of the Mabs were bound to linear peptides forming four independent binding regions (I-IV). Binding region I was localized to amino acid residues 1-13 (identical sequence for PSA and hK2), II (a and b) was localized to residues 53-64, III (a and b) was localized to residues 80-91 (= kallikrein loop), and IV was localized to residues 151-164. Mabs binding to regions I and IIa were reactive with free PSA, PSA-ACT complex, and with hK2; Mabs binding to regions IIb, IIIa, and IV were reactive with free PSA and PSA-ACT complex, but unreactive with hK2; Mabs binding to region IIIb detected free PSA only. All Mabs tested (n = 7) specific for free PSA reacted with kallikrein loop (binding region IIIb). The presence of Mabs interacting with binding region I did not inhibit the catalytic activity of PSA, whereas Mabs interacting with other binding regions inhibited the catalysis. Theoretical model structures of PSA, hK2, and the PSA-ACT complex were combined with the presented data to suggest an overall orientation of PSA with regard to ACT.

Amino Acid Sequence↗
PubMed1998

[The effect of nimodipine on retinal blood flow in pregnancy induced hypertension].

OBJECTIVE: To assess the effects of nimodipine on retinal blood flow in patients with pregnancy induced hypertension (PIH). METHODS: Fourteen patients were studied with color flow Doppler before and after 30 mg nimodipine administered orally, while other fourteen patients received intravenous magnesium sulfate as control group. Central retinal artery flow velocity waveforms were measured and pulse index (PI) were calculated. RESULTS: Nimodipine reduced the central retinal artery PI significantly from 0.92 +/- 0.14 to 0.75 +/- 0.22. It also reduced systolic blood pressure from 20.7 +/- 2.5 kPa to 19.8 +/- 1.5 kPa and diastolic blood pressure from 14.4 +/- 2.3 kPa to 13.6 +/- 1.9 kPa. CONCLUSIONS: Nimodipine may dilate central retinal arteries. Changes in pulsatility index in retinal arteries maybe indicative of similar changes in other cerebral vessels. Nimodipine may be another choice of PIH therapy.

Adult↗
PubMed1998

[The inhibitory effect of melatonin on morphine withdrawal syndromes and serum monoamines in morphine dependent mice].

OBJECTIVE: To observe the inhibitory effect of melatonin on morphine withdrawal syndromes and serum monoamines in morphine dependent mice. METHODS: A physical dependent model in mice was established by subcutaneous injection of morphine. The intensity of withdrawal syndromes was evaluated according to the jumping latency and jumping times. The concentration of serum monoamines was detected with HPLC-ECD. RESULTS: The physical withdrawal syndromes in morphine dependent mice were inhibited partly by four different doses (25, 50, 100, 200 mg/kg) of melatonin and showed a significant dose-dependent manner. The increased concentration of serum norepinephrine and dopamine in morphine-dependent mice could be reduced by large dose (100 mg/kg) of melatonin. CONCLUSION: The jumping withdrawal syndromes and serum monoamiues in morphine-dependent mice could be inhibited partly by melatonin.

Animals↗
PubMed1998

Suicide effect on rat gliomas mediated by recombinant adenovirus thymidine kinase/acyclovir system.

OBJECTIVE: To establish the replicated-deficient recombinant adenovirus-mediated thymidine kinase/acyclovir (Adtk/ACV) system and to evaluate its suicide effect on rat C6 brain gliomas in vitro and in vivo. METHODS: The plasmid pAdtk and pJM17 were co-infected into 293 cells (adenovector packaging cells) and the results were identified by polymerase chain reaction (PCR) assay. After the glioma C6 cells were transduced by Adtk at different multiplicity of infection (MOI) and exposed to different concentrations of ACV or gancyclovir (GCV), the cell survival curves were studied, and the cell surface was observed with scanning electronic microscopy (SEM). C6 gliomas in vivo at different inoculation days were injected with Adtk intratumorally and ACV intraperitoneally daily, and the survival duration and histologic changes of the rats were observed. RESULTS: The infectious Adtk virions had a suicide effect which was enhanced with the increase in MOIs of Adtk and ACV doses along with bystander effect. Under scanning electronic microscope, special pathologic changes were observed. ACV had a similar effect as GCV but a higher dose was used. The survival duration in day 3, day 6 and day 8 groups exceeded 90 days, and the rats in day 10 group survived 28.5 +/- 4.6 days, but the survival duration in untreated C6 group and AdLacZ/ACV (adenovirus-mediated LacZ/ACV) treated group were 16.8 +/- 3.1 and 14.0 +/- 2.2 days respectively. CONCLUSION: Adtk/ACV system can effectively kill the rat brain gliomas in vitro and in vivo.

Acyclovir↗
PubMed1998

Polymorphism of DXS102 locus in Chinese population and its application to gene diagnosis in hemophilia B family.

OBJECTIVE: To establish the polymorphism of DXS102 locus from Xq26.3-27.1 in Chinese population for the gene diagnosis in Hemophilia B family. METHODS: DNA was extracted from blood samples obtained from Shanghai unrelated volunteer donors with phenol-chloroform method. A total of 23x chromosomes (154 from females, 80 from males) were studied. A hemophilia B family in which a hemophilia B patient has received gene therapy was analyzed. The polymorphism of DXS102 locus in Chinese population was determined with amplified fragment length polymorphisms assay (Amp-FLP), denaturing polyacrylamide gel electrophoresis, silver stain detection. Short tandem repeats (STRs) linkage analysis was used to conduct gene diagnosis in hemophilia B family. RESULTS: Eight alleles were found at DXS102 locus, of which two alleles were first reported. The repeated number of AC dinucleotide ranges from 13 to 21. And the values of the observed heterozygosity, calculated heterozygosity and polymorphism information content(PIC) were 0.87, 0.80, 0.80 respectively. It was also found that the difference of the allele frequencies of DXS102 in Chinese and European populations was significant. By using the linkage analysis of the DXS102 locus, a family with a hemophilia B patient receiving gene therapy in 1994 was analyzed and meanwhile a carrier in that family was then detected. CONCLUSIONS: The polymorphism of DXS102 locus reveals significant difference between Chinese and European populations. DXS102 locus can be used as a promising marker for gene diagnosis in hemophilia B family.

Alleles↗
PubMed1998

[Effect of Acorus tatarinowii Schott. on gastrointestinal myoelectric activity in rats].

The effect of Acorus tatarinowii on the gastrointestinal myoelectric activity and mechanism in rats was studied electrio-physiologically. The result indicates that Acorus tatarinowii helps inhibit the gastrointestinal myoelectric activity. This inhibitory effect is believed to take place through the blocking of cholinergic M and non-cholinergic M receptors, and has nothing to do with adrenergic alpha and beta receptors.

Acorus↗
PubMed1998

[Effect of yuanhua on isolated uterine strips in unpregnant rats].

OBJECTIVE: To explore the mechanism on the effect of Yuanhua on the contractile activity of isolated uterine strips in rats under artificial oestrum. METHOD: Isolated strips were suspended in a tissue chamber in which Yuanhua was added with some antagonists of inhibitors or without. RESULT: Yuanhua could excite the uterine smooth muscle strips in a dose-dependent manner, but atropine, phentolamine, hexamethonium and diphenhydramine could not inhibit this exciting action. This exciting effect could be inhibited completely by verapamil and decreased by indomethacin(inhibitor of prostaglandin synthase). CONCLUSION: The exciting effect of Yuanhua on un-pregnant rats in vitro might be related to an action on the cell membrane Ca2+ channel as well as to a partial stimulation of synthesis and release of PG.

Animals↗
PubMed1998

[Bone scintigraphy in evaluating revascularization of the heat-devitalised autografts in adult dogs].

OBJECTIVE: To establish an animal model of microwave hyperthermic devitalization of long bones and compare bone scintigraphy of the devitalised bone with pathologic examination. METHOD: 16 Mongrel adult dogs were used. Enght 8 cm of one femur of each dog was exposed and isolated by heat-proof material. Two microwave antennas were inserted into the medullary cavity at a distance of 2.5 cm, and the bone was heated intermittently to maintain a surface temperature of 50 degrees C to 60 degrees C for 30 minutes. Bone scintigraphy was carried out at different postoperative time, combined with tetracycline labeling, microangiography with Indian ink and HE staining. RESULT: About 5 cm - 6 cm of segmental femur was deprived of blood supply after devitalization which was confirmed by microangiography and negative labeling of tetracyclines. At two weeks, the devitalised bone demonstrated a cold region on the scintiscan and no revascularization in microangiography. 12 - 16 weeks after the operation, partial devitalised bone was revascularized and HE staining showed widel bone resorption and minimum formation of new bone. However, the radionuclide uptakes of the devitalised segments were greater than those of the normal femurs. At one year, the devitalised segment was well (not completely) revascularised and showed evident appositional new bone formation. The scintigraphic bone-imaging was slightly lower than that of the normal femur. CONCLUSION: A strong positive scintiscan in early stage might demonstrate a good potential of revascularization of the heat-devitalised cortical bone rather than its viability. And the scintiscans of long-term follow-up more than one year should be more informative.

Angiography↗
PubMed1998

[Vitrectomy for treatment of retinal detachment caused by macular hole].

OBJECTIVE: To evaluate the effect of vitrectomy and autoserum for treatment of retinal detachment caused by macular hole. METHODS: 19 eyes with retinal detachment caused by macular hole were treated with gas tamponade (C(3)F(8)). The follow-up periods ranged from 6 to 24 months. In the case whose macular hole failed to heal, removal of the remains of prefoveal membrane and/or scratching at the retinal pigment epithelium (RPE) and placing autoserum for 7 minutes in the macular hole were performed. RESULTS: Closure of macular hole was obtained in 15 eyes (80%). The postoperative visual acuity was 0.05 - 0.4. Macular hole failed to heal in 4 eyes. In one eye the remains of prefoveal membrane were removed; in another 3 eyes, in the macular hole scratching at the retinal pigment epithelium (RPE) and placing autoserum were performed and C(3)F(8) tamponade was used. Anatomical cure was obtained in all the 4 eyes. The final visual acuity was 0.1 or better. CONCLUSION: The findings show that removal of prefoveal membrane is imperative. Scratch at RPE with placement of autoserum in the macular hole is effective for the macular hole which has failed to respond to conventional vitrectomy with air tamponade.

Aged↗
PubMed1998

[The synthesis and immunosuppressive effects of steroid-peptide linkers].

Hydrocortisone was coupled with urotoxin tripeptide UTP-A, UTP-B and UTP-C respectively yielding 4 linkers. Their bioactivities such as prolongation of heterotopic transplanted cardiac tissue survival, inhibitory effects on phagocytosis of mouse peritoneal macrophages and the influence on Con A induced proliferation of spleen lymphocytes of mouse were observed. Compared with UTP-A, UTP-B, UTP-C or hydrocortisone the linkers were more potent immunosuppressants. The results suggest that the linker of steroid-peptide may simulate the permissive action.

Animals↗
PubMed1998

[Effect of melatonin on mean blood pressure and heart rate in morphine withdrawal rats].

The model of morphine dependent rats was established by gradually increasing the doses of morphine by subcutaneous injection(from 5 mg.kg-1 to 50 mg.kg-1, 5 days). The effects of melatonin(MT) on the mean arterial blood pressure(mABP) and heart rate(HR) were studied in naloxone-precipitated rats. MT was found to inhibit the hypertention and tachycardiac syndromes in morphine withdrawal rats in dose-dependent manner. The concentration of serum norepinephrine(NE) was shown to be decreased by MT. Moreover, regitine was shown to inhibit the increase of mABP in morphine withdrawal rats, but can not inhibit the increase of HR. These results suggest that the inhibitory effect of MT on hypertension and tachycardiac syndromes in morphine withdrawal rats may be mediated by the inhibitory effect of the drug on the sympathetic system.

Animals↗