Biomedical subjects

Q Chen

Publications and source records attributed to Q Chen.

At least 559 records · Page 31Linked to original sources

PubMed1996

[Experimental study of R plasmid eliminating action of Coptis chinensis on E. coli].

The R plasmid curing experiment was performed in vitro with E. coli strain E. 102 bearing R plasmid as target bacteria and Coptis chinensis as elimination agent. The influence of different time on R plasmid elimination was also observed. Results showed that when the acting time was 24 hours, the cure rate of R plasmid was 2.42% and when the acting time increased to 48 hours, the cure rate elevated to 22.57%. The Missing patterns of R plasmid might be occurred in disappearence of either multiple or single resistance.

Drugs, Chinese Herbal↗

PubMed1996

Sequencing of combined hyperthermia and photodynamic therapy.

Photodynamic therapy (PDT) and hyperthermia are two alternative tumor treatment modalities currently being investigated in clinical trials. It has been suggested that, due to the differences in cell-killing mechanisms, synergetic tumor responses may be achieved if the two modalities are combined in appropriate sequences. This hypothesis is tested in the current study by delivering graded PDT doses during a transient tumor reoxygenation period after a hyperthermia treatment, or delivering graded hyperthermia doses when the tumor becomes acidic and hypoxic after a PDT treatment. The results indicate that the latter combination sequence has a profound effect on tumor response. While treating the tumors with PDT followed by hyperthermia evokes a synergetic tumor response, reversing the sequence results only in an additive effect. Possible mechanisms associated with tissue oxygenation are discussed.

Animals↗

PubMed1996

[Study on infertility caused by infections of Chlamydia trachomatis and ureaplasma urealyticum].

OBJECTIVE: To explore the effects of chlamydia trachomatis (CT) and ureaplasma urealyticum (UU) infections on male and female infertility. METHODS: Samples from cervical canal or male urethra of 1198 infertile patients (599 couples) were studied and from 167 normal fertile men and women served as control. The fluorescent monoclonal antibody technique and the culture method were used for CT and UU assays respectively. RESULTS: The positive rates of CT and UU infections in infertile group were 25.5% (306/1 198) and 35.9% (167/1 198) respectively, while 6.6% (11/167) and 15.6% (26/167) in the control group respectively. There were significant differences between the 2 groups (P < 0.01). After treatment of positive patients, the pregnancy rates were higher in those patients became negative than that in patients remained positive (P < 0.01). CONCLUSION: The CT and UU infections were one of the factors causing infertility.

Adult↗

PubMed1996

Induction of met proto-oncogene (hepatocyte growth factor receptor) expression during human monocyte-macrophage differentiation.

The met proto-oncogene encodes the cell surface receptor for hepatocyte growth factor (HGF) and transmits its multifunctional signals such as regulation of cell proliferation, motility, and morphogenesis. These pleiotropic actions attributable to HGF are mainly reported on cells of epithelial derivation which express the Met receptor. The HGF gene, on the other hand, is expressed in mesenchymally derived cells including peripheral blood leukocytes. Recently, we reported that Met receptor gene expression in epithelial cells is induced by inflammatory cytokines; currently, however, little is known concerning Met gene expression in mesenchymal cells. In the present study, we have explored the role of Met expression during monocyte-macrophage differentiation using THP-1 cells, a monocytic cell line, and monocytes freshly isolated from normal human peripheral blood. We have found that untreated monocytes do not express Met mRNA and protein. Upon incubation with differentiation inducers such as 12-O-tetradecanoylphorbol-13-acetate, lipopolysaccharide, a combination of interleukin (IL) 6 plus tumor necrosis factor (TNF) alpha, or IFN-gamma plus TNF-alpha, a pronounced increase in the amounts of Met mRNA and protein are seen in THP-1 cells. The expression of Met appears to correlate with the onset of differentiation of monocytes as noted by changes in cell morphology and adherence to culture plates, and the increased accumulation of Met protein was observed only in cells that differentiated and adhered to the culture dish. Moreover, Met was found to be phosphorylated on tyrosine residues, indicating that the receptor is potentially involved in signal transduction events. Addition of exogenous HGF to the activated cells resulted in the suppression of cell proliferation and an increase in cell motility. Reverse transcription-PCR and Western blot analyses revealed that untreated THP-1 cells contain HGF transcript and protein, and that HGF expression is inducible by addition of the differentiation agents such as 12-O-tetradecanoylphorbol-13 acetate or IL-6 plus TNF-alpha. Immune serum that is specific for neutralizing HGF activity markedly inhibited monocyte differentiation (50% reduction in cell attachment and process formation) induced by IL-6 and TNF-alpha. Moreover, we also found that the mRNA for Ron, which encodes a tyrosine kinase receptor for HGF-like protein (also known as macrophage-stimulating protein), is induced in THP-1 cells during the course of their differentiation to macrophages by IFN-gamma plus TNF-alpha. These findings indicate that the HGF and Met families may indeed be physiological regulators of monocyte-macrophage differentiation/maturation.

Cell Differentiation↗

PubMed1996

Functional inhibition of rat polymorphonuclear leukocyte B2 integrins by hyperbaric oxygen is associated with impaired cGMP synthesis.

We hypothesized that hyperbaric oxygen caused a metabolic derangement in polymorphonuclear leukocytes that impaired the function of B2 integrins. Isolated neutrophils from rats that had been exposed to 3 atm oxygen for 45 min failed to exhibit B2 integrin-dependent adherence to nylon columns or to fibrinogen-coated plates. Adherence was restored after cells were incubated with 8-bromo-cGMP, phorbol 12-myristate 13-acetate (PMA) or the reducing agent dithioerythritol. Hyperbaric oxygen was found to inhibit cGMP synthesis that normally occurred when cells were stimulated by passage through nylon columns, and exposure to PMA or dithioerythritol reestablished cGMP synthesis. Cells adherent to plastic plates synthesized cGMP when they were exposed to N-formyl-methionyl-leucine-phenylalanine (FMLP) or PMA. Neutrophils from rats exposed to hyperbaric oxygen synthesized cGMP in response to PMA but failed to respond to FMLP, although hyperbaric oxygen did not alter the affinity of the FMLP receptor or its associated G protein. Dithioerythritol restored the cGMP synthetic ability of adherent neutrophils in response to FMLP. We conclude that hyperbaric oxygen inhibits B2 integrin-dependent adherence because it impairs cGMP synthesis by activated neutrophils.

Animals↗

PubMed1996

[The relation between indirect fetal electrocardiogram and blood gas analysis of umbilical cord artery during labor].

OBJECTIVE: To observe the relation between indirect fetal electrocardiogram (FECG) and blood gas analysis of umbilical cord artery blood during labor and discuss the possibility of using FECG for labor monitoring. METHODS: Indirect FECG was used for fetal monitoring in 80 cases during the second stage of labor and cord umbilical artery blood was taken immediately after delivery for blood gas analysis. Cases were retrospectively divided into normal and abnormal groups according to the results of FECG. RESULTS: The success rate of FECG test was 91.95%. Significant differences were noted in mean values of pH, PCO2, PO2, actual base excess (ABE) and standard base excess (SBE) of umbilical artery between the 2 groups, so were the percentages of cases with pH < 7.20, PCO2 > 8.00 kPa, PO2 < 2.10 kPa. CONCLUSIONS: Indirect FECG can be used for fetal monitoring during labor. FECG is obviously correlated with acid-base equilibrium and blood gas concentration of umbilical cord artery blood, it is a sensitive index of fetal and neonatal hypoxia.

Adult↗

PubMed1996

[Endolaser photocoagulation in vitrectomy surgery].

OBJECTIVE: To verify the usefulness and effectiveness of endolaser photocoagulation in vitrectomy. METHODS: Endolaser photocoagulation was applied in 40 cases (45 eyes) of vitrectomy surgery. Indications for vitrectomy included vitreous hemorrhage 31 eyes (proliferative diabetic retinopathy 13, Eales's disease 13, retinal vein occlusion 4, and scleral penetrating injury with intraocular foreign body removal 1), complex retinal detachment 12 eyes, intraocular nonmagnetic foreign body removal and postoperative silicone oil tamponade 1 eye respectively. Treatment involved pan-retinal scatter therapy in 7 eyes, focal therapy in 22 eyes, sealing primary or iatrogenic retinal breaks in 14 eyes, draining retinotomy in 2 eyes, and encircling scleral buckle photocoagulation in 3 eyes. The follow-up times ranged from 2 to 18 months (average 9 months). RESULTS: Whitening of laser spots was not apparent in 6 eyes with retinal breaks following incomplete gas-fluid exchange. Recurrent retinal detachments occurred in 5 eyes postoperatively. CONCLUSION: Endolaser photocoagulation facilitates the performance and reduces the complications of vitrectomy surgery.

Adolescent↗

PubMed1996

[Three dimensional reconstruction of human endometrial spiral arteries preinsertion and postinsertion of IUD].

OBJECTIVE: To investigate the micro-three dimensional changes of endometrial spiral arteries after insertion of different intrauterine devices (IUD). METHODS: Nine endometrium specimens were obtained from fertile age women, 3 from preinsertion, 3 obtained 3 months after insertion of TCu220C IUD, and 3 specimens obtained 3 months after insertion of gamma Cu IUD (releasing indomethacin 20 micrograms/day). All samples were collected in late secretory phase and were sectioned serially. By a TV camera, the images of sections were sent from a light microscope to a computer and converted into digital data. The spiral arteries of endometrium were reconstructed and visualized on a workstation by means of the software package for the three dimensional reconstruction and visualization. The curvature and torsion of the spiral arteries were calculated. RESULTS: In preinsertion group, the spiral arteries curved regularly in three dimensions, and the average diameter was 22.69 microns, the average curvature was 0.96 and the average torsion was 1.27. The spiral arteries of gamma Cu IUD group had similar appearances as the preinsertion group. However, in TCu220C IUD group, the curves were irregular, and the average diameter was 17.99 microns, the average curvature was 1.48 and average torsion 1.86. CONCLUSION: The three dimensional reconstruction of human endometrial spiral arteries was done by means of computerassisted reconstruction technology for the first time. The endometrium spiral arteries changed in morphology after insertion of copper IUD, and indomethacin may have contrary effects on copper.

Adult↗

PubMed1996

[Effects of electroacupuncture at du meridian on contents of nitric oxide and endothelin in rats with acute cerebral ischemia].

Thirty rats were randomly assigned to three groups, control group (10 cases), acute cerebral ischemia group (10 cases) and electroacupuncture (EA) group (10 cases). The bilateral common carotid arteries were occluded, which caused sharp drop of regional cerebral bloodflow and led acute cerebral ischemia. Contents of nitric oxide (NO) and endothalin (ET) in the cerebral cortex and boold were determined in normal, during occluding and after EA of Du meridian (GV 20, GV 14) point in rats. It was found that in acute cerebral ischemia, the brain contents of NO and ET increased, the plasme level of ET elevated and serum level of NO decreased. After EA of Du meridian point, the levels of ET and NO in the brain and blood were returned significantly to normal. It is suggested that EA at Du meridian have protective effect on neural damage induced by brain ischemia. NO and ET are possibly involved in the regulative effect of EA.

Animals↗

PubMed1996

[The evaluation of clinical staging by preoperative CT examination in patients with bladder cancer].

50 patients with bladder cancer, treated from september 1988 to September 1994 was analysed to compare preoperative CT examination with postoperative pathological diagnosis. The coincident staging of CT and pathological finding was found to be 86% (43/50). In the remaining 7 patients, 4 were of overstaging and 3 were of understaging respectively. The cause of incorrecting staging by preoperative CT was usualy due to the difficulty in determing if lymph node metastasis occurs. It is suggested that to improve the preoperative CT staging, the thin phase scanning to the area of lymph nodes around the iliac artery and obsturatorius should be carried out if the patient has been confirmed to have hydronephrosis.

Adult↗

PubMed1996

[Eighty-seven cases of male infertility treated by bushen shengjing pill in clinical observation and evaluation on its curative effect].

Eighty-seven cases of male infertility with semen abnormality were treated and observed by Bushen Shengjing Pill, its curative effect was evaluated with quantitative assessment and analytical comparison comprehensive scoring of semen routine analysis. These patients were treated for one to three courses of treatment, the semen quality was enhanced obviously, the comprehensive semen routine analysis score was enhanced significantly (P < 0.001) as compared with that before treatment, the spouse pregnant rate was 56.32% (49/87), and total effective rate was 95.40% (83/87). The result showed that this prescription had bidirectional regulatory function in folliclestimulating hormone, luteotropic hormone, testosterone, corticosterone, and could make the enhanced or reduced hormone level to normal value.

Adult↗

PubMed1996

[Community trial for safety and immunogenicity of oral-administered lyophilized rBS-WC cholera vaccine].

In order to evaluate the safety and immunogenicity of domestic produced lyophilized recombinant, B-subunit, inactivated whole cell vaccine of vibrio cholerae (rBS-WC), 369 subjects were randomly divided into three groups and observed with masking method, one with high dose of vaccine (5 mg rBS and 10" WC), another with low dose (1 mg rBS and 10" WC), and the control one with placebo. Three doses of vaccine were given orally at an interval of seven days and 14 days, respectively. Results showed that only one subject had mild adverse reaction in the vaccine group (1/247) and none in the control group. Serum and fecal antibody conversion rates and average levels of antibodies in the two vaccine groups were significantly higher than those in control one. There was no significant difference in serum and fecal antibody conversion rate and average antibody levels between the two vaccine groups. But, antibody response was different among subjects of various sex, age, and vaccine doses. It indicates that rBS-WC vaccine of vibrio cholerae had good immunogenicity and safety.

Administration, Oral↗

PubMed1996

[Negative binomial distribution of eggs of Schistosoma japonicum in stool].

To understand the nature of distribution of schistosoma japonicum (S. japonicum) eggs in stool of the infected individuals, it is assumed that if regression coefficient b approaches two in the equation lg (v) = a + blg(m), with a larger mean of egg counts (m), they can be considered compatible with negative binomial distribution. Results of this study showed egg counts of S. japonicum in stool of the same infected individual on different days and in male and female population can be described by negative binomial distribution, with 95 percent confidence intervals of coefficient of regression 1.3006-2.2956, 1.6109-1.9703, 1.7060-2.1589, and 1.5507-2.2359, respectively. Goodness of fit tests for the observed data indicated that fitting for negative binomial distribution was good. It suggests that the method of moments (coefficient of regression) can be used to determine whether the observed distribution of frequencies is compatible with a negative binomial one.

Animals↗

PubMed1996

[The role of p53 gene during the development of human oral malignant lesions: a comparative study of p53 gene mutation with P53 protein positive immunostaining].

In order to increase the sensitivity to immunostaining in formalinfixed, paraffin-embedded tissues, we developed an immunohistochemical method by microwave heating of tissue sections instead of trypsin digestion. The results of this study showed that there was no positive P53 protein reaction in normal and hyperplastic mucousa of human mouth, whereas 90% (27/30) of cases with dysplasia, 61% (30/49) of oral squamous cell carcinomas and 86% (13/15) of regional metastatic lymph nodes were positive. And all positive reactions were localized in nuclei. Comparison of these positive results of p53 gene mutation detected by silver staining method with the results by polymerase chain reaction-single strand conformation polymorphism analysis did not reveal matched results, especially during the precancerous period. The authors analysed the causes of difference not only by methodology, but also by cell groups which had different genetic changes in tissues of precancerous lesions.

Carcinoma, Squamous Cell↗

PubMed1996

[Study clinical application to determine heparin requirements during hemodialysis].

A de nove Weighted Stepwise Linear Model based on Gotch's heparin pharmacokinetic model has been designed to determine the heparin elimination rate constant during hemodialysis (HD). 100 times of HD in 26 patients with unstable dosage requirements of heparin were performed according to the computing method and the new heparin pharmacokinetic Weighted Stepwise Linear Model monitored be program of pocket calculator. The results showed not only stable anticoagulation but also successful prevention of patients's bleeding and avoidance of coagulation in hemodialyzer and blood tubing. The computer diagram presented in this paper is useful for propramming with different computer languages to calculate the heparin dosage requirements of patients undergoing HD.

Computers↗

PubMed1996

[Clinical application of a new mobile integrated orbital implant].

OBJECTIVE: To improve the socket reconstruction after enucleation. METHODS: Hydroxyapatite (HA, made in China) was made into a porous HA sphere and wrapped up in the scleral shell as a mobile integrated orbital implant. It was applied to 43 patients with enucleation and anophthalmia, The surgical technique is described. RESULTS: All sockets have been corrected very well and the prosthetic mobility and the cosmetic appearance are excellent. After a follow-up of 6 to 24 months, no migration or extrusion of the implant or infection occurred. CONCLUSION: It is considered that at present this new mobile integrated orbital implant is made of one of the best materials and this method of socket reconstruction is one of the best method for selection.

Adolescent↗

PubMed1996

[Domestic silicone oil, removal and complications].

OBJECTIVE: To master the optimal time of domestic silicone oil (DSiO) removal after vitreoretinal surgery and to observe the complications after it removal. METHODS: DSiO removal was performed through a superior corneoscleral limbus or pars plana incision in 64 cases. RESULTS: The rate of the attached retina was 85.5% after DSiO removal. The visual acuity was improved or unchanged in 53 cases (82.8%). In 27 cases followed up postoperatively for an average of 11.6 months, the retina remained attached in 18 cases (66.7%). The postoperative complications included retinal redetachment in 12 cases and intraocular hemorrhage in 4 cases. CONCLUSION: 3-6 months after operation is the best time for removing DSiO when retinal tears are healed and DSiO is not emulsified.

Adolescent↗

PubMed1996

[The role of P53 gene in the development of oral squamous cell carcinoma: study of P53 gene mutation by silver staining polymerase chain reaction-single strand conformation polymorphism].

It is widely accepted that the inactivation of P53 tumor suppressor gene is related to the tumorigenesis of many cancers. The study on P53 tumor suppressor gene has become a hotspot in molecular oncology. But until now, the reports on the research of the role of P53 gene in the tumorigenesis and prognosis of oral squamous cell carcinoma are scarce. So, two studies have been carried out. (1) A silver staining method of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis was established by detecting the mobility shifts of the DNA bands of the products of PCR of mutant P53 gene plasmid and the Sup F mutants which had been proved to have point mutation by DNA sequencing in shuttle vector plasmid pS 189 mutagenesised by N-methyl-N-nito-N-nitosoguanidine (MNNG). For the method is non-radiation with high sensitive, it has applicable value. (2) By silver staining PCR-SSCP system, tissues from normal oral mucoas membrane to metastatic oral squamous cell carcinoma (OSCC) were analyzed and the results showed that tissues from 53% oral precancerous lesions and 65% OSCC had abnormal SSCP bands and the abnormal frequency of metastatic cancers was higher than that of nonmetastatic ones. These suggest that P53 gene mutation plays some role on the process of initiation, development and metastasis of OSCC.

Adult↗