Biomedical subjects

X Xu

Publications and source records attributed to X Xu.

At least 505 records · Page 28Linked to original sources

PubMed1999

[The effect of the molecular triggers of hemostatic activity on thrombosis in early stage of electrical injuries].

OBJECTIVE: To evaluate the mechanisms of thrombosis in the early stage of electrical injury. METHODS: Endothelin-1(ET-1), prostacylin(PGI2), platelet alpha-granule membrane protein (Gmp-140), thromboxane (TXB2), and plasminogen(PLG-A) were measured in 26 patients with electrical injury. RESULTS: It was found that GMP-140 and ET-1 increased significantly(P < 0.01), PLG-A showed a significant change 2 weeks after the injury, while there was an imbalance between TXB2 and PGI2. CONCLUSION: It is believed that change in one or several mediators mentioned above may trigger thrombosis after electrical injury.

Adolescent↗

PubMed1999

Treatment of early giant retinal tears with domestic perfluorodecalin and perfluoropropane.

OBJECTIVE: To explore the methods of lens-sparing (without lensectomy), non-silicone oil tamponade and no scleral buckling for treatment of early giant retinal tears. METHODS: Thirteen cases of early retinal detachment of proliferative vitreoretinopathy (PVR) grade C2-D1, with giant tear extending from 135 degrees to 270 degrees were chosen. Transscleral cryotherapy was first applied to treat each end of the giant tear up to the oral serrate. And then conventional three-port pars plana vitrectomy was performed. Perfluorodecalin liquid was injected to manipulate the flap of the retinal tear. The flap with no cryotherapy before was treated with endolaser or cryotherapy under optimal visual condition, then air-fluid was exchanged completely and C3F8 was injected properly. RESULTS: With a mean follow-up of 8.2 months, the retina was reattached completely in 12 eyes. Success rate was 92.3%, and visual acuity improved. Most postoperative complications were slight. The retina failed to reattach only in 1 case with severe vitreous blood. CONCLUSIONS: In treating early retinal giant tears without severe PVR, the lens-sparing, non-silicone oil tamponade and no scleral bucking are helpful to simplify operation and to improve the success rate of the retinal surgery and to yield satisfactory outcome of visual acuity. Besides, it can also avoid the initial side effects of silicone oil tamponade and diopter irregularity after lensectomy.

Adult↗

PubMed1999

[Direct genotyping of an hereditary persistence of fetal hemoglobin deletion and rapid prenatal diagnosis of the fetus at-risk for compound heterozygote of this defect with beta-thalassemia in a Chinese family].

OBJECTIVE: To investigate the relationship between genotype and phenotype of a deletional hereditary persistence of fetal hemoglobin(HPFH) found in a Chinese family and explore an approach to rapid prenatal diagnosis for compound heterozygote of HPFH defects with beta-thalassemia. METHODS: By using the PCR-based method with three primers bridging a HPFH breakpoint and reverse dot blot (RDB) for detecting beta-thalassemia mutations, a Chinese family who had a propositus of six years old with intermediate thalassemia and requested prenatal diagnosis for the second pregnancy were screened. RESULTS: The propositus carried the HPFH deletion determinant inherited from her mother, and a codons 14-15 (+G) frameshift mutation causing beta-thalassemia from her father. Of six members in this family screened for this type of HPFH deletion, four were positive. Prenatal diagnosis of the fetus showed the same results as that of the propositus. An advice of termination of pregnancy was given and the result of prenatal diagnosis was confirmed in the DNA samples obtained after abortion. CONCLUSIONS: This is the first time to have performed prenatal diagnosis of Chinese family at-risk for compound heterozygotes for beta-thalassemia and HPFH in mainland China. The PCR assay for directly detecting the HPFH deletion is rapid and inexpensive and can be used as a routine in HPFH carrier screening and prenatal diagnosis.

Adult↗

PubMed1999

Effect of burn healing liquid on keratinocyte and fibroblast proliferation and on collagen lattice contraction.

OBJECTIVES: To investigate the effect of Burn Healing Liquid (BHL) on the proliferation of keratinocytes and fibroblasts and to explore the potential effect of BHL on fibroblast contraction. METHODS: Human keratinocytes and dermal fibroblasts were cultured in media containing serial dilutions of BHL followed by cell proliferation determination assessed with MTT (3-[4, 5-dimehtylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide) assay at different time intervals. The in vitro collagen lattice contraction model was utilized for determining the contractility of fibroblasts cultured in BHL containing medium. RESULTS: The 1:10(7) dilution of BHL enhanced the growth of both keratinocytes and fibroblasts whereas the 1:10 dilution increased the growth of keratinocytes only. Collagen lattice contraction was inhibited dose-dependently by BHL and such an inhibition could be reversed by switching BHL containing medium to normal medium containing 10% fetal calf serum. CONCLUSION: BHL enhances the growth of both keratinocytes and fibroblasts and reversibly inhibits the fibroblast contraction in collagen lattice.

Burns↗

PubMed1999

Rapid expression of vascular endothelial growth factor in early acute myocardial ischemia in rats.

OBJECTIVE: To study the expression of vascular endothelial growth factor (VEGF) in different parts of heart during early acute myocardial ischemia. METHODS: The expression of VEGF in control and study group in rats was performed with the Strept Avidin-Biotin-Peroxidase Complex (SABC) method. RESULTS: A rapid expression of VEGF in ischemic areas was observed 1 hour after the ligation of rat left anterior descending (LAD) coronary artery, and in peri-ischemic and non-ischemic areas 3 hours after ischemia. The grade of expression of VEGF increased with the continuation of myocardial ischemia, the positive myocytes of SABC-VEGF staining mainly localized in peri-ischemic areas 5 hours after ischemia. No expression of VEGF in control group was found. CONCLUSION: The expression of VEGF may be up-regulated in rapid and continuous manner with characteristic spatial and temporal kinetic during early acute myocardial ischemia.

Animals↗

PubMed1999

Expression of leukocyte adhesion molecules CD11b, L-selectin and CD45 during hemodialysis.

OBJECTIVE: To examine the gene and protein expression of CD11b, L-selectin and CD45, and the relationship between their expression and leukocytopenia during a hemodialysis session. METHODS: Ten maintenance hemodialysis patients, 20 uremic non-dialysis patients and 10 healthy volunteers were included in this study. The mRNA expression of CD11b, L-selectin and CD45 in peripheral blood mononuclear cells was detected by RT-PCR, while cell surface expression of these molecules on monocytes was detected by flow cytometry and leukocyte number was counted manually. RESULTS: After the start of dialysis, both mRNA expression and cell surface expression of CD11b increased rapidly, while those of L-selectin and leukocyte number fell. The mRNA expression of CD45 first decreased and the cell surface expression increased, followed by a return to pre-dialysis levels, by the end of dialysis. CONCLUSIONS: Hemodialysis using a cuprophane membrane can induce rapid upregulation of CD11b and down-regulation of L-selectin, which might influence the normal adhesion and anti-inflammatory response of leukocytes. In this process CD45 may play a role in regulating and/or transducing activation signal.

Adult↗

PubMed1999

[Respiratory effects of beta-endorphin in chronic hypoxic rats].

OBJECTIVE: To assess the role of beta-EP in the physiological and pathophysiological process of respiratory regulation in chronic hypoxic rats. METHODS: The chronic hypoxic rat model was established by intravenous injections of papain 6 times, once a week. The concentration of beta-endorphin in medulla, pons, hypothalamus, central gray and plasma of chronic hypoxic rats were measured by radioimmunoassay. All animals were pretreated with sodium pentobartital (35 mg/kg) before experiment. 102 rats were randomly divided into three groups. Group 1 (n = 36). The respiratory rate (RR) and tidal volume (VT) were measured after intravenous injection of naloxone (NLX, 2 mg/kg), beta-EP (40 micrograms/kg, 160 micrograms/kg) or normal saline, Group 2 (n = 48). By the intracerebroventricular administration of NLX and beta-EP to the models, RR, VT and PaCO2 were observed after microinjection 5, 15, 30, 45, 60 min. Group 3 (n = 18). The respiratory effects of beta-EP after directly into the nucleus tractus solitari of the anaesthetised rats were investigated. RESULTS: The beta-EP contents in medulla, pons, hypothalamus, central gray and plasma of chronic hypoxic rats were significantly increased compared with control subjects (P < 0.01). It suggested that the pathophysiology of chronic hypoxic process infleuced the contents of beta-EP in the CNS and plasma in rats. Intracerebroventricular microinjection of beta-EP in normal rats, resulted in a significant decrease in RR (P < 0.05). No significant difference in RR and VT was observved after intravenous injection of naloxone (2 mg/kg) and beta-EP (40 micrograms/kg, 160 micrograms/kg) in treatment group compared with the control group (P > 0.05), Intracerebroventricular microinjection of NLX in chronic hypoxic rats, resulted in a marked increase in RR (P < 0.05) and central hypercapnic-sensitivity (t = 2.76, P < 0.05), Intracerebroventriculalr microinjection of beta-EP in chronic hypoxic models, resulted in severe respiratory depression after injection 15, 30, 45, 60 min (RR t = 3.41, 6.54, 6.97, 7.87, P < 0.01; VT t = 3.07, 7.27, 6.14, 6.08). CONCLUSIONS: These results indicate the beta-endorphin may be involved in central respiratory control of chronic hypoxic rats.

Animals↗

PubMed1999

[Three dimensional finite element analysis of effects on composite resin for filling in various cavity margin design].

OBJECTIVE: To evaluate the stress distribution of different angles of cavity margins with composite resin filling. METHODS: The stress distributions of different angles of cavity margins of class I cavity of molars were analyzed by the method of three dimensional finite element. The cavity was filled with composite resin and the stress vertical force and lateral force was calculated. RESULTS: In the 5 designed different cavity margin angles, the vertical forces and lateral forces were 18.757 MPa and 22.309 MPa respectively when the angle is 90 degrees; when the angles were 75 degrees and 60 degrees, they were 10.580 MPa, 14.265 MPa and 9.025 MPa, 13.230 MPa respectively. The vertical forces and lateral forces produced by the surface of composite resin while being stressed were up to 18.757 MPa and 22.309 MPa. The forces of the second layer evidently reduced to 2.586 MPa and 6.8 MPa. CONCLUSION: When fill the molars with resin in clinic, the angles of cavity margins should be prepared with the slopes of 60 degrees to 75 degrees.

Composite Resins↗

PubMed1999

[Vascularized illiac bone grafts and reconstruction of the mandible].

OBJECTIVE: To investigate method of reconstructing large mandible defects. METHODS: Seven cases of mandibular defects were reconstructed with vascularied illiac bone grafts supplied by circumflex illiac vessels and Bränemark osseointegration implants immediately. RESULTS: Six months after operation, X-rays showed osseointegration between implants and graft bone. After 6 months to 36 months of follow-up, all implants were stable and no radiolucency was found and the functions were satisfactory in mastication, pronunciation and facial contour. CONCLUSION: Reconstruction of large mandible defects by vascularized illiac bone grafts supplied by circumflex illiac vessels and Bränemark osseointegration implants immediately is promising.

Adolescent↗

PubMed1999

[Changes of serum elastase, alpha 1-antitrypsin, procollagen III peptide and malonaldehyde in smokers with and without chronic obstructive pulmonary diseases].

OBJECTIVE: Serum elastase, alpha(1)-antitrypsin (alpha(1)-AT), procollagen III peptide (PIIIP) and malonaldehyde (MDA) were studied in smokers with and without chronic obstructive pulmonary disease (COPD) to explore the roles of these factors in COPD induced by smoking. METHODS: A design of 154-pair case-control study was used. alpha(1)-AT, MDA and PIIIP were determined with colorimetric method, fluo-spectrophotometric method and radio-immunological assay, respectively, in non-smoker control and smokers with and without COPD. RESULTS: Serum PIIIP content was increased in smokers and alpha(1)-AT decreased significantly in patients with COPD. CONCLUSION: Decreased alpha(1)-AT may be a susceptible factor in the development of COPD caused by smoking.

Adult↗

PubMed1999

[The detection of T-cell receptor gene rearrangement in myelodysplastic syndromes].

OBJECTIVE: To analyse the T cell receptor (TCR) gene rearrangement in myelodysplastic syndromes (MDS). METHODS: Polymerase chain reaction (PCR) was used to detect the TCRVgammaI-Jgamma gene rearrangement in 36 cases of MDS. RESULTS: 8 cases (22.2%) were found to have TCRVgammaI-Jgamma gene rearrangement. The TCR gene rearrangement positive rate was higher in RAEB, CMML and RAEBT subtypes than that in RA and RAS subtypes (P < 0.05). The average time MDS evolving to acute leukemia was shorter in the MDS patients with TCRVgammaI-Jgamma for gene rearrangement than that in patients without (P < 0.01). CONCLUSION: TCR gamma gene rearrangement can also be found in some MDS patients and the detection of TCRgamma gene rearrangement might be helpful to identify the prognosis and the development of MDS.

Adolescent↗

PubMed1999

[Monitoring of bacteria resistance in burn patients].

OBJECTIVE: To monitor the bacteria resistance in burn patients. METHODS: Disk susceptibility tests were performed and interpreted according to the NCCLS criteria. Four kinds of the third generation cephalosporins extended-spectrum beta-lactamase produced by multi-resistant of P. aeruginosa and K. Pneumoniae strains were detected after 20 microgram of sulbactam was added respectively, in contrast to no sulbactam. RESULTS: 227 strains were isolated from burn patients. 195 strains (86%) were gram-negative bacteria. Disk susceptibility showed various bacteria had high antibiotic resistance and multi-resistant rate. S. aureus was only susceptible to vancomycin, its resistant rate to imipenem was 19%. P. aeruginosa was only susceptible to polymyxin-B, its resistant rate to ceftazidime was 20%. However, after stop using ceftazidime two years, the susceptibility to gram-negative bacteria recovered. The resistant rate of ceftazidime to P. aeruginosa, E. coli, K. pneumoniae were decreased respectively. The resistance to quinolones was increased. The resistant rate of ciprofloxacin to P. aeruginosa, K. pneumoniae was increased respectively. After 20 microgram sulbactam added to cephalosporins drug disks, the primary susceptibility of ceftazidime to P. aeruginosa and K. pneumoniae recovered, and the antibiotic was better than the other cephalosporins. CONCLUSIONS: It is important to monitor the bacteriology in burn patients at all time, and understand the changing pattern of bacterial flora, antibiotic susceptibility and bacterial strains spreading in burn ward. Extended-spectrum beta-lactamases is the cause of resistance. After sulbactam added to the third generation of cephalosporins, the beta-lactamases were inhibited, and the susceptibility of antibiotics to bacteria were increased and ceftazidime was prior to others.

Anti-Bacterial Agents↗

PubMed1999

[Treatment of benign prostatic hyperplasia with laser through the endoscope].

OBJECTIVE: To evaluate the effect of transurethral laser prostatectomy (TULP) and its relation with the size of prostate. METHODS: 469 benign prostatic hyperplasia receiving TULP from 1988 to 1998 were reviewed retrospectively, and the methods of operation and preoperative and postoperative symptom were compared. The effect of 233 patients undergoing TULP was compared with the size of the prostate. RESULTS: The average value for IPSS of 469 patients decreased from 26.7 (preoperation) to 14.2 (postoperation). The mean value of maximum uroflow rate increased from 6.2 ml/s (preoperation) to 11.8 ml/s (postoperation). No difference was seen in postoperative effect between the transurethral contact and noncontact laser prostatectomy. If the estimating weight of prostate exceeded 50 g, the maximum flow rate after 3 years was decreased evidently, the value of IPSS increased to over 20. CONCLUSIONS: If the estimating weight of prostate is less than 50 g, TULP is indicated.

Aged↗

PubMed1999

[Comparison of subclinical infection rates between vaccinated group with type I inactivated vaccine against hemorrhagic fever and controls].

OBJECTIVE: To compare subclinical infection rate in the vaccinated group with type I inactivated vaccine against hemorrhagic fever with renal syndrome (HFRS) with that in the controls and to understand its enhancement. METHODS: A trial field was selected in Jiande County, Zhejiang Province during July 1974 to November 1997. Paired-sera before and after vaccination were collected from 401 vaccinee and 360 controls, respectively. Serum titer of indirect immunofluorescent IgG antibody (IFAT) against HFRS was detected for each of them, and its cut-off value depended on the distribution of serum antibody titer in the second determination in the controls, which could be used to evaluate subclinical infection before vaccination. RESULTS: There was no significant difference in subclinical infection between those with positive and negative IFAT before vaccination, with different cut-off values for identifying subclinical infection. In both vaccinated and control groups with negative IFA before vaccination, subclinical infection rate was 7.62% in the controls, and 2.17% and 1.63% in the vaccinated ones, with cut-off values of 1:160 and 1:320, respectively, significantly different from that in the former. Subclinical infection rate was 11.38% and 6.78% in the vaccinated ones, as cut-off values of 1:20 and 1:40, respectively, without significant difference from the controls. CONCLUSION: No increase in subclinical infection in the vaccinated group with type I inactivated vaccine against HFRS was found.

Adolescent↗

PubMed1999

[A study on immunogenicity and safety of bivalent inactivated vaccine against hemorrhagic fever with renal syndrome].

OBJECTIVE: To study side effects and effectiveness of bivalent inactivated vaccine against hemorrhagic fever with renal syndrome in population of a randomized controlled field trial. METHODS: Serum indirect immunofluorescent antibody in 167 persons and neutralization antibody (types I and II) in 69 persons, who received three-dose vaccine, were determined two weeks after immunization, and side effects in 657 vaccinees were observed within 72 houses after immunization. RESULTS: Serum positive conversion rate of indirect immunofluorescent antibody was 99.04% (166/167) with GMT of 24.51 +/- 2.06. Serum positive conversion rate of neutralization antibody was 100% (69/69), 91.30% (63/69) for types I and 88.41% (61/69) for type II, respectively. GMTs for type I and II neutralization antibody were 18.27 +/- 2.21 and 12.47 +/- 2.16, respectively. Side effects at local site vaccinated of the body and temperature rising could be seen in 1.48% and 0.36% of the vaccinees, respectively. No severe side effect and abnormal reaction was found in vaccinees on the field. CONCLUSION: Immune response to bivalent inactivated vaccine against hemorrhagic fever with renal syndrome was satisfactory with slight side effect.

Adolescent↗

PubMed1999

[The amyloidosis in cardiac conduction system].

OBJECTIVE: To investigate the relationship between arrhythmia, cardiac failure and amyloidosis of cardiac conduction system (CCS). METHODS: CCS from 6 cases with cardiac amyloidosis were sampled using technique designed by the authors. The CCS were studied by Congo red staining and polarization microscopy. RESULTS: Pathological changes could be found in the CCS of these 6 cases. It was serious in sino-atrial node while slight in atrio-ventricular conduction system. The changes in atrio-ventricular conduction system were exacerbated from proximal part (atrio-ventricular node) to distal part (left bundle branch). In the 3 cases with sinus bradycardia and conduction blocking manifested by electrocardiogram, the pathological changes in CCS were more extensive and serious than that of other cases. CONCLUSION: The amyloidosis in CCS is one of the pathological bases of arrhythmia.

Aged↗

PubMed1999

[The analysis of pathological changes of cardiac conduction system in 54 cases of cardiac sudden deaths].

OBJECTIVE: To elucidate the exact cause of death in cases of cardiac sudden deaths. METHODS: Sampling of cardiac conduction system (CCS) designed by the research group was adopted. The CCS of 120 cases died of cardiac sudden deaths were collected for routine histological examination. RESULTS: In 54 out of 120 cases, the causes of death were attributed to lesions present in the CCS, and 85.2% of them were young adults. The peak age range was from 20 - 30. Much more in males (6.7:1). The pathological changes in CCS include: inflammation (46.2%), fatty infiltration, hypertrophic cardiomyopathy associated with CCS changes; hemorrhage, developmental anomalies, fibrosis and tumors. CONCLUSION: The pathological changes of CCS are relatively common, as the cause of sudden deaths. Which is considered to be the pathological basis of the unstable cardiac electric potentials and arrhythmia. This study recommended the necessity of routine examination on CCS in cases of sudden deaths.

Adult↗

PubMed1999

[Effect of fluoride exposure on synaptic structure of brain areas related to learning-memory in mice].

The learning-memory behavior was tested in mice on a Y-maze after drinking different concentration of sodium fluoride. The impairment on the structure of Gray 1 synaptic interface in the CA3 area of mice hippocampus were quantitatively analyzed by electron microscopy and computer image processing appliance. The main results are as follows: the learning ability of mice drinking high concentration of fluoride presented remarkable deterioration, the thickness of post-synaptic density (PSD) was decreased, and the width of synaptic cleft was remarkably increased. The results suggested that the impairment on the learning capability induced by fluorosis may be closely related with the pathological changes of synaptic structure in the brain of mice.

Animals↗