Biomedical subjects

Y Xu

Publications and source records attributed to Y Xu.

At least 433 records · Page 24Linked to original sources

PubMed2000

[Pharmacokinetics of topically applied in-situ-forming gels of fluconazole in rabbit eyes].

AIM: To study the pharmcokinetics of fluconazole (FCZ) in the aqueous humors and tears of New Zealand white rabbits following topically applied in-situ-forming gels of 0.5% FCZ (ISG-FCZ) and 0.5% FCZ eye drops to rabbit eyes. METHODS: The rabbit tears and aqueous humors were obtained and quantified at different times after topically applying single dose of ISG-FCZ and FCZ eye drops to the rabbit eyes. The drug levels were assayed by megabore capillary gas-liquid chromatography with nitrogen-selective detector. The pharmacokinetic parameters were calculated with nonlinear least square method with computer. RESULTS: FCZ concentrations in rabbit tears within 180 min after applying ISG-FCZ were found to be significantly higher compared with those of FCZ eye drops. The FCZ levels in the aqueous at 10, 30, 60, 90 and 120 min after applying ISG-FCZ are significantly higher compared with FCZ eye drops. The time for arriving peak concentration (Tmax) and the area under concentration (AUC)-time curve as well as the half-life (T1/2) of FCZ in rabbit aqueous humors were markedly higher after application of ISG-FCZ. The peak levels in the aqueous humors showed no difference between the two groups. CONCLUSION: The ISG-FCZ, which upon exposure to physiological conditions will shift the gel phase, can significantly extend FCZ release and increase the precorneal residence time of the drug, thus enhance ocular bioavailability compared with FCZ eye drops.

Acrylic Resins↗

PubMed2000

[Expression of recombinant human soluble Flt3 ligand and its in vitro effects on malignant hematopoietic cells].

OBJECTIVE: To express human soluble Flt3 ligand in a yeast expression system. Pichia pastoris, and investigate the effects of recombinant human soluble Flt3 ligand (rhFL) on the proliferation of malignant hematopoietic cells(MHC) and the effect of dexamethasone (DXM) on the expression of Flt3 receptor (Flt3R) and the rhFL induced proliferation of those cells. METHODS: An artificial gene for rhFL was synthesized by using favored genetic codons of the yeast Pichia pastoris. Flt3R was determined by flow cytometry. Proliferation of MHCs was measured by microculture tetrazolium (MTT) assay. RESULTS: 1. An expression vector, pPICZ alpha A-FL, was constructed and electroporated into Pichia pastoris. A yield of over 30 mg/L of yeast culture supernatant was obtained. The rhFL could stimulate the proliferation of Raji and HL-60 cells at concentrations of 10-100 ng/ml, but did not for most of other MHCs. 2. Flt3R was expressed in 5 of 18 MHC lines and the expression in leukemic blast cells was widespread and extremely heterogeneous. 3. The presence of the receptor on the surface of MHC did not necessarily imply a significant ligand-induced response, at least in terms of proliferation. By contrast, some Flt3R-negative MHC responded to rhFL. 4. DXM down-regulated the expression of Flt3R and inhibited the proliferation induced by rhFL in some MHC lines and fresh leukemia cell samples. CONCLUSION: A yield of 30 mg/L of rhFL was obtained. rhFL stimulated the proliferation of Raji, HL-60 cells and some fresh leukemia cells, which could be inhibited by DXM through down-regulation of Flt3R. A combination of FL and DXM might possibly serve to control hematopoietic defects in malignant hematopoietic diseases.

Antineoplastic Agents, Hormonal↗

PubMed2000

A clinical investigation on garlicin injectio for treatment of unstable angina pectoris and its actions on plasma endothelin and blood sugar levels.

To investigate the therapeutic effects and mechanisms of garlicin for treatment of unstable angina pectoris (UAP), garlicin injectio was intravenously dripped 60 mg/day in 34 cases for 10 days. Nitroglycerine was used in 21 cases of the control group. The results showed that the total effective rates in improving symptoms and electrocardiogram after garlicin treatment were respectively 82% and 62%, and that the plasma endothelin and blood sugar levels were markedly lowered in cases with hyperglycemia.

Aged↗

PubMed2000

[The effect of ginkgo biloba on hypoxic pulmonary hypertension and the role of protein kinase C].

OBJECTIVE: To elucidate whether the mechanism of relieving hypoxic hypertension by ginkgo biloba involves attenuation of the function of protein kinase C(PKC) signal channel. METHODS: 1. Wistar rats were randomly divided into control(C), hypoxic(H) and ginkgo biloba treatment(GB + H) (200 mg.kg-1.d-1, orally) groups (n = 7). Each rat was first measured mean pulmonary arterial pressure (mPAP), mean systemic arterial pressure (mSAP) and the ratio of the weight of right ventricle to that of left ventricle plus septum [RV/(LV + S)], than two main pulmonary artery rings were isolated to exposed to PDBu(a specific activator of PKC) to observe the time-response curve and the dose-response curve in response to 500 nmol/L PDBu and 10-11,000 nmol/L PDBu respectively to evaluate the function of protein kinase C signal channel. 2. Intrapulmonary artery rings of human(IARH) from pneumolobectomy were randomly divided into PDBu, RO318220 (inhibitor of PKC) + PDBu and ginkgolide B(BN52021) + PDBu groups(n = 6), the IARH of three groups were exposed to 1-25 nmol/L PDBu to achieve dose-response curves respectively. RESULTS: (1) mPAP, RV/(LV + S) of the H group were greater than those of C and GB + H groups respectively (P < 0.05). mPAP of GB + H group was greater than that of C group (P < 0.05). In PA experiments, the function of protein kinase C of H group was higher than those of C and GB + H groups respectively(P < 0.05). (2) In IARH experiments, the function of protein kinase C of PDBu group was higher than those of RO318220 + PDBu and BN52021 + PDBu groups respectively(P < 0.05). CONCLUSIONS: Ginkgo biloba can reduce chronic hypoxic pulmonary hypertension and relieve the hypertrophy of right ventricle, which is partly related to attenuation of the function of PKC signal channel.

Animals↗

PubMed2000

[Effect of osmotic stress on wheat membrane injury under different CO2 concentrations].

This paper studied the variation of active oxygen content and membrane permeability in leaves of spring wheat seedling exposed to osmotic stress under normal 350 microliters.L-1 and doubled CO2 concentration 700 microliters.L-1. The results indicate that the increasing rate of O2.- and H2O2, and the membrane permeability in wheat leaves exposed to osmotic stress in normal CO2 concentration were higher than those in doubled CO2. Accordingly, it is suggested that doubled CO2 can reduce the membrane oxidative injury caused by osmotic stress, and increase plant drought resistance.

Carbon Dioxide↗

PubMed2000

[Effect of long-term no-tillage and application of organic manure on some properties of soil fertility in rice/wheat rotation].

A field experiment from June 1983 to October 1997 was conducted to study the effect of long-term no-tillage and application of manure on soil fertility properties. The results showed that the contents of soil organic C, total N and available N in the treatment of fourteen consecutive year no-tillage were all significantly higher in 0-5 cm soil layer, while, lower in 5-10 and 10-20 cm layers than in conventional tillage. The content of water stable aggregate in 0-20 cm layer was increased in no-tillage in that the soil structure was less destroyed. Based on various soil fertility properties, the contribution order of different fertilization treatments to soil fertility was as follows: pig manure > straw > green manure > chemical fertilizer > no fertilizer.

Manure↗

PubMed2000

Changes in airway responsiveness and relative factors in asthma with remission at puberty.

OBJECTIVE: To elucidate the airway responsiveness and its relative factors in asthma with natural remission at puberty. METHOD: The airway responsiveness was evaluated by provocation of methacholine (PC20). Blood sIL-2R, IL-4 and IFN-gamma values in the cultural supernatant of mononuclear cells, eosinophil count, basophil count and basophil releasability were detected in 18 asthmatic cases with remission at puberty (group I), in 20 asthmatics without remission at puberty (group II), and in 30 healthy controls (group III). RESULT: The mean value of PC20 in group I was significantly lower than that in group III (P < 0.01), but still higher than that in group II (P < 0.01). The blood sIL-2R, and eosinophil counts dropped almost to those of group III, significantly lower than those of group II. IL-4 in the culture supernatant of mononuclear cells was similar to group III, but significantly lower than that in group II. However IFN-gamma was also similar to group III, significantly higher than that of group II. The basophil count and positive rate of human basophil degranulation test stimulated by mannitol with hyper-osmolarity were still abnormal, significantly higher than those of group III, and the basophil level was significantly related to the airway responsiveness. CONCLUSION: The asthmatics with remission at puberty have a certain degree of airway hyper-responsiveness that is related to the abnormality of basophil.

Adolescent↗

PubMed2000

Identification of a mutation hotspot in exon 8 of Wilson disease gene by cycle sequencing.

OBJECTIVE: To screen for mutation hotspot of Wilson disease (WD) gene in Chinese population. METHODS: Cycle sequencing was used to detect mutation in exon 8 of WD gene in 30 patients with Wilson disease. RESULTS: The same missense mutation, Arg779Leu, was identified in 14 WD patients, four of whom were homozygous and the other heterozygous for this mutation. The frequency of this mutation in Chinese patients was 30%. CONCLUSION: The codon 779 (CCG-->CTG) of exon 8 of WD gene was one of mutation hotspots in Chinese.

Adenosine Triphosphatases↗

PubMed2000

[Preliminary analysis of chromosome mosaicism in preimplantation embryos].

OBJECTIVE: Using fluorescence in situ hybridization to analyze chromosome mosaicism in human preimplantation embryos and access the influence of mosaicism on in vitro fertilization-embryo transfer (IVF-ET) and preimplantation genetic diagnosis. METHODS: Normal fertilized embryos, which were not suitable for embryo transfer and cryopreservation, and male embryos in preimplantation gender diagnosis were analyzed by fluorescence in situ hybridization. RESULTS: Two hundred and ninety three nucleuses were found among 38 embryos. The hybridization rate was 96.2%. Twelve embryos (31.6%) were normal. Twenty-eight embryos (73.7%) were diploid embryos, which included normal diploid embryos and embryos with diploid moscaicism. In addition, 19 (50.0%) embryos were considered to be chromosomal mosaics due to diploid mosaicism and abnormal mosaicsm. The frequency of mosaicism increased from 18.2% in < or = 4 cell-stage embryos to 68.4% and 50.0% in 5-8 cell-stage and > or = 9 cell-stage embryos respectively. CONCLUSION: The frequency of Mosaicism increases with successive cleavage divisions. Moscaicism may be one of the important factors affecting the success rates in IVF-ET. Identification of sex by analysis of a single cleavage cell is accurate; however, it would be better to biopsy 2 cells to reduce errors in preimplantation genetic diagnosis of single gene diseases.

Blastocyst↗

PubMed2000

[Detecting embryo sex by fluorescence in-situ hybridization in preimplantation genetic diagnosis].

OBJECTIVE: Applying fluorescence in situ hybridization(FISH) in preimplantation gender diagnosis. METHODS: Ovarian hyperstimulation was performed in 2 hemophilia A carriers and 2 patients with Y chromosome abnormality. Embryo sex was identified by single blastomere FISH after embryo biopsy. Female embryos were transferred into uterus. RESULTS: A total of 110 cumulus-oocyte complex were retrieved in 5 treatment cycles. Among them, 68.2% showed normal fertilized pronuclei and 55 embryos were available for embryo biopsy. The success rate of biopsy was 85.5%, with further cleavage rate of 61.7%. In FISH procedure, one cell was lost during fixation, led to 97.9% fixation rate. Totally, 18 female embryos were diagnosed and 16 were transferred into uterus. Two clinical and one biochemical pregnancies were achieved. The diagnosis was confirmed by the following analysis of aminocyte and embryonic buds after embryo reduction respectively. CONCLUSIONS: FISH is an efficient and accurate technique for determination of the sex of human preimplantation embryos. Selective abortion and birth of affected child can be avoided by preimplantation gender diagnosis.

Female↗

PubMed2000

[The number of lymph node with metastases influences survival in patients with cancer of the thoracic esophagus].

OBJECTIVE: To study the extent of lymph node involvement in relation to survival of patients with thoracic esophageal carcinoma. METHODS: From 1990 to 1993, there were 112 patients with thoracic esophageal carcinoma undergone esophagectomy through right thoracotomy and three-field lymphadenectomy. They were classified into three groups: group A, 44 patients without lymph node involvement; group B, 36 patients with 1 to 3 positive nodes; group C, 32 patients with > or = 4 involved lymph nodes. Nine possible factors influencing survival were studied. A multivariate analysis of these variables was performed using the cumulative survival rate by the computer's Cox proportional hazard model. RESULTS: The over-all cumulative survival rate was 58.4% at 5 years. That for patients in group A, B and C was 88.4%, 50.8% and 20.8%, respectively. Apart from the extent of lymph node metastases, depth of tumor invasion, location and differentiation of tumor were of prognostic significance. CONCLUSION: Lymph node metastasis is the major factor affecting survival of patients with cancer of the thoracic esophagus.

Adult↗

PubMed2000

[Clinical study on treatment of mild-middle degree congestive heart failure with integrated traditional Chinese and Western medicine].

OBJECTIVE: To evaluate the effect of combined use of Chinese herbal medicine, Captopril and Metoprolol in treating mild-middle degree congestive heart failure. METHODS: One hundred and fifty patients studied were divided into 3 groups, the Group A treated with Chinese herbal medicine, Group B treated with Captopril plus Metoprolol and Group C treated with both Chinese and western medicines. Parameters on cardiac functions were observed and compared 3 weaks and 3 months after treatment respectively. RESULTS: (1) The cure rate in the Group A, B and C was 72%, 86% and 94% respectively. (2) Effect of echocardiogram: ultrasound cardiogram showed that the left ventricular diastolic diameter in Group C was less significantly than that in Group A and B (P < 0.05). (3) The eject fraction in Group C was higher than that in the other two groups (P < 0.05). (4) The 24 hours dynamic electrocardiogram demonstrated a significant lowering occurrence of ventricular premature contraction in Group C in comparing with that in Group A and B (P < 0.05). CONCLUSION: Good effect would be expected in treating mild-middle degree congestive heart failure by using Chinese herbal medicine combined with Captopril and Metoprolol.

Adrenergic beta-Antagonists↗

PubMed2000

[Multicenter evaluation of the antimicrobial activity in vitro for six broad-spectrum beta-lactams in China using the E-test method].

OBJECTIVE: To investigate the in vitro activities of cefepime and other 5 beta-lactam antimicrobial agents against 937 strains isolated from 10 teaching hospitals in different geographical areas in China during the early 1998. METHODS: The MIC values of cefepime, ceftazidime, ceftriaxone, imipenem, cefoperazone/sulbactum, and piperacillin against 937 isolates were tested by a gradient concentration method (E-test((R)); AB Biodisk Co.). RESULTS: Quality control isolates were tested in all working processes. MIC values of 96.5% (829/859 times) of quality assurance tests were within expected ranges of NCCLS. Only imipenem and cefepime could inhibit 90% of enterobacter and citrobacter strains, Cefepime were significantly more active than 3rd Generation cephalosporins in enterobacter and citrobacter strains, and little better active than E. coli and Klebsiella spp. (98%, 95% susceptibility). All tested antimicrobial excluding ceftazidime had very high activity to oxacillin susceptible Staphylococci (95% approximately 100% susceptibility). cefepime, ceftazidime, imipenem, and cefoperazone/sulbactum had similar activity to Pseudomonas aeruginosa (83% approximately 79% susceptibility). Both imipenem and cefoperazone/ sulbactum were very active to Acinetobacter spp. (97%, 89% susceptibility). CONCLUSION: The rank order of activity of the six tested agents is imipenem (97% Susceptible) > cefepime (89%) > cefoperazone/sulbactum (86%) > ceftazidime (76%) > ceftraixone (67%) > piperacillin (57%). The data are helpful to guide empiric therapy with beta-lactams in China.

Anti-Bacterial Agents↗

PubMed2000

[Apoptosis of endothelial cells in alteration of microvascular permeability in lung during sepsis].

OBJECTIVE: To investigate the apoptosis of endothelial cells in the alteration of microvascular permeability in lung during sepsis. METHODS: Twenty-four male NIH mice were subjected to cecal ligation and puncture (CLP) or sham operation (SO). The microvascular endothelial cells of the lungs were harvested at 3 hours and 12 hours after operation. The apoptosis of endothelial cells (VIII factor related antigen positive cells) in the lungs was determined by 2-color flow cytometry (FITC-labeled VIII factor related antigen and PI) and Apop Tag) in situ apoptosis detection kit in situ. The apoptosis related gene (bcl-2) was detected by RT-PCR. The microvascular permeability in lung tissue was also examined. RESULTS: The apoptosis of microvascular endothelial cells was increased significantly at 12 hours after CLP (5.03 +/- 0.92 vs. 3.48 +/- 1.21, P < 0.05). The increased apoptosis was paralleled with the decrease in bcl-2 gene expression. The microvascular permeability in lung tissue was slightly increased at 3 hours after CLP, but significantly increased at 12 hours after CLP (0.106 +/- 0.008 vs 0.047 +/- 0.003, P < 0.01). CONCLUSIONS: Apoptosis in microvascular endothelial cells seems to be an important reason for the alteration of microvascular permeability.

Animals↗

PubMed2000

[Remodelling of the spinal canal after thoracolumbar burst fractures: significance of nonoperative management].

OBJECTIVES: To determine the phenomenon of remodelling of the spinal canal after thoracolumbar burst fracture and to investigate the efficacy of nonoperative management. METHODS: A total of 31 patients with thoracolumbar burst fractures, including 7 untreated, 16 treated nonoperatively, and 8 treated operatively, were retrospectively analysed and followed up for 3 to 7 year. The initial and final degrees of neurological deficit and stenotic ratio of the spinal canal were recorded. RESULTS: The stenotic ratio significantly decreased (P < 0.01) from the discharge (range: 12.3% to 74.5%, average: 26.2%) to the final follow-up (range: 5.4% to 46.5%, average: 19.2%), but there were no differences (P > 0.05) of stenotic ratio improvement among the patients untreated, and treated nonoperatively and operatively, or among the patients with different degree of neurological deficit. CONCLUSIONS: Significant remodelling of the spinal canal develops after thoracolumbar burst fractures. Nonoperative management may be taken into account for treatment of neurological intact patients with thoracolumbar burst fractures.

Adult↗

PubMed2000

[An experimental study on F-heparin surface modified IOLs implanted into the Rhesus monkeys' eyes].

OBJECTIVE: To evaluate the biocompatibility of F-heparin surface modified IOLs. METHODS: 13 monkeys were divided into 3 groups, and implanted with different surface modified and non-modified IOLs into their eyes. All of the eyes were examined by slitlamp microscope and Schiötz tonometer at postoperative 15, 30, 60, 90 and 180 days. Postoperatively, at different periods the aqueous was aspirated from the anterior chamber to calculate cells. RESULTS: F-heparin surface modified IOLs induced milder inflammatory reaction and less dense posterior capsula opacification (PCO) than non-modified IOLs. CONCLUSION: F-heparin surface modified IOL has a better biocompatibility.

Animals↗

PubMed2000

[Long-term observation of curative effects of posterior scleral reinforcement surgery in patients with juvenile progressive myopia].

OBJECTIVE: To evaluate the long-term curative effects of the scleral reinforcement surgery in juvenile progressive myopia. METHOD: 25 patients (34 eyes) with the disease (average age, 17.12 +/- 7.47 years old) were observed for 3 to 5 years after posterior scleral reinforcement surgery. RESULTS: The naked visual acuities at postoperative one and three years were better than that before the operation (P < 0.01). The average axial elongation in the first, third and fifth year after the operation was 0.098 mm/year, 0.073 5 mm/year and 0.115 mm/year, respectively; the increment of refractive diopter was smaller than 0.50 D/year. CONCLUSION: The scleral reinforcement surgery is a safe and effective treatment for juvenile progressive myopia.

Adolescent↗

PubMed2000

[A serological investigation of Legionella infection in eight-species of poultry and domestic animals in Sichuan province].

OBJECTIVE: To understand the prevalence rates of Legionella infection in poultries and domestic animals in Sichuan province. METHODS: Serological investigation of antibodies against Legionella pneumophila serogroups 1 - 14 and Legionella micdadei was carried out, using microagglutination test (MAT) in eight species of poultries and domestic animals. RESULTS: Infections with multiple serogroups were identified. However, each species had its own major serogroup with positive rates of different serogroups ranging from 0.83% to 59.18%. Positive rates of the poultry and domestic animals were accounted for 7.73% and 4.25% respectively. CONCLUSION: It was suggested that poultries and domestic animals were widely infected with Legionella. It is important to carry out epidemiological surveillance in these domestic animals, poultries and environment for a better control program of this disease.

Animals↗