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Biomedical subjects

X Zheng

Publications and source records attributed to X Zheng.

At least 127 records · Page 7Linked to original sources
PubMed2000

[Microsurgical treatment of medially located tumors of the middle skull base].

OBJECTIVE: To report the results of microsurgical treatment of tumors medially located in the middle skull base. METHODS: The preoperative MRI features, operative approaches, results of operation and postoperative complications in 26 cases were reviewed. RESULTS: Total resection of the tumors was achieved in 12 cases, subtotal resection in 9 cases, partial resection in 6 cases. Two patients died of operation. Cranial nerve palsy remained unchanged in 5 cases and became exacerbated in 5 cases. Clinical improvement was observed in 15 cases. CONCLUSION: The combined frontotemporal-zygomatic approach to remove medially located tumors of the middle skull base is adequate.

Adolescent↗
PubMed2000

[Induction of apoptosis in various cancer cell lines by human soluble TRAIL expressed in Escherichia coli].

OBJECTIVE: To investigate the induction of apoptosis by human soluble TRAIL expressed in Escherichia coli and analyze its relationship with p53 in various cancer cell lines, especially the solid tumor. METHODS: TRAIL codons 114 approximately 281 were amplified by polymerase chain reaction. The soluble segment was expressed in Escherichia coli JF1125, refolded and purified. Induction of apoptosis was assessed by examination of morphological changes under electron microscope and quantified by FACS analysis. The mutation of p53 in employed cell lines was detected by immunohistochemistry. RESULTS: By multi-step purification, the purity of human soluble TRAIL exceeded 90%. Induction of apoptosis by the product exhibited a marked increase in human breast cancer cell line MCF-7, HeLa cervical carcinoma cells and hepatocellular carcinoma cell lines SMMC7721, BEL7402, and BEL7405. The mutation of p53 in employed cell lines was positive in aforementioned cell lines. CONCLUSION: The human soluble TRAIL expressed in Escherichia coli has similar activity to that generated in cells to induce apoptosis in various cancer cell lines, and acts independently of p53.

Apoptosis↗
PubMed2000

[Optical coherence tomography applied for measurement of nerve fiber layer thickness in normal eyes].

OBJECTIVE: To evaluate the efficiency of optical coherence tomography (OCT) on quantifying retinal nerve fiber layer (RNFL) thickness and its reproducibility and investigate the difference of RNFL thickness between different groups. METHODS: According to their age, 152 eyes of 152 normal subjects were classified into six groups (such as 10 year, 20 year group, etc.), and investigated by OCT to measure the RNFL thickness. Each subject had circular scans around the optic nerve with a circle size of 3.46 mm. The RNFL thickness in different groups was analyzed. Intraclass correlation coefficient (ICC) in fifty eyes of 37 subjects was calculated. RESULTS: The mean RNFL thickness of 152 eyes was (90.09 +/- 10.81) microm, (140.27 +/- 10.60) microm, (85.03 +/- 14.01) microm, (140.27 +/- 9.70) microm and (114.11 +/- 6.08) microm (temporal, superior, nasal, inferior and the mean of the whole layer, respectively). Least significant difference (LSD)-t test was applied for multiple thickness comparisons of the mean and different quadrants among different groups. The results showed there were significant differences between the 60 year group and others except the 50 year group in temporal, superior, inferior quadrants and mean RNFL thickness (P = 0.000 - 0.019), and between each of 10 to 40 year groups and each of 50 to 60 year groups in the mean RFNL thickness (P = 0.000 - 0.026). ICCs of RNFL thickness measured by OCT were 0.78, 0.66, 0.64, 0.52 and 0.74 (temporal, superior, nasal, inferior and mean, respectively). CONCLUSIONS: Normal RNFL thickness can be measured accurately by OCT. There are some differences of RNFL thickness between different groups in normal persons.

Adolescent↗
PubMed2000

[Qualitative and quantitative measurement of retinal nerve fiber layer in primary open angle glaucoma by optical coherence tomography].

OBJECTIVE: To study the characteristics of optical coherence tomography (OCT) of primary open angle glaucoma (POAG), the difference of retinal nerve fiber layer (RNFL) thickness between normal persons and patients with POAG and the correlation between RNLF and visual field index. METHODS: Eighty-three cases (149 eyes) with POAG and 83 normal persons (150 eyes) were tested by OCT with circular scans around the optic nerve head (diameter = 3.46 mm) to observe the features of OCT. Statistic analysis was taken to compare the difference of RNFL thickness in quadrants and means between normal and glaucomatous group, and the difference of the thickness among the stages in POAG. Linear correlation and regression analysis was used to show the correlation between RNFL thickness and visual field index of 115 eyes of glaucomatous patients. RESULTS: The RNFL thickness measured by OCT in normal subjects is the thickest in superior and inferior quadrants, less in thickness in temporal and the thinnest in nasal quadrant. The curve showed double peaks. The RNFL of glaucomatous patients showed local thinness or defect, diffuse thinness or combination of the above two types. The mean RNFL thickness of normal group was (90.1 +/- 10.8) microm, (140.4 +/- 10.5) microm, (85.2 +/- 14.0) microm, (140.4 +/- 9.7) microm and (114.2 +/- 6.0) microm, of glaucomatous group was (56.0 +/- 31.0) microm, (81.0 +/- 36.3) microm, (47.1 +/- 27.5) microm, (73.4 +/- 38.4) microm and (64.6 +/- 28.8) microm in temporal, superior, nasal, inferior quadrant and the whole area, respectively. There is significant difference of RNFL thickness between the normal and glaucomatous group (P < 0.000), and there are significant differences among the three stages (early, developing and late) of glaucomatous group (P < 0.000). There is a close negative relationship between RNFL thickness and visual field index (r = -0.796, P < 0.0001). The sensitivity and specificity of RNFL thickness measured by OCT were 93.3% and 92.0%, respectively. CONCLUSION: OCT can quantitatively measure the RNFL thickness and show the difference of RNFL between normal persons and glaucomatous patients. The RNFL thickness gradually decreases while visual field defect increases with the development of POAG.

Adolescent↗
PubMed2000

[The survey of prevalence of HIV infection among paid blood donors in one county in China].

OBJECTIVE: To estimate the prevalence rate of HIV infection among paid blood donors and to analyse high risk factors. METHOD: All residents between 18 to 60 years old were selected from on county in March 1999. RESULTS: There were 210 paid blood donors among 730 interviewed subjects. The HIV prevalence rate among paid blood donors was higher (9.1% or 19/210) than that of others (0.6% or 3/520). The HIV prevalence rate was higher in plasma donors (25.9%) than that (2.6%) among 210 blood donors. Donors who donated blood/plasma more than 10 times each year had a higher prevalence rate (13.5%) than those who donated less than 10 times each year (2.8%). Donors who had donated blood but stopped donation before 1995 had a higher prevalence rate (18.3%) than those who started donation after 1996 (1.4%). The results of KAP survey showed that blood donors had a low knowledge about AIDS. CONCLUSION: There was a higher prevalence rate of HIV infection among paid blood donors in some regions. It should take measures to prevent further transmission HIV through paid blood donors.

Adolescent↗
PubMed2000

[Residual risk research of HIV infection after blood screening in one county in China].

OBJECTIVE: To estimate the risk of HIV infections from blood transfusions, to evaluate existing blood screening measures, and to make recommendations to improve current blood screening practices. METHODS: Research was conducted in a county blood station. A statistical model and retrospective method were used to analyse the data. RESULTS: Between June 1995 and March 1998, 19 blood donors tested positive for HIV antibodies and among them, 7 were repeat blood donors. Twenty - two blood recipients were identified from these 7 donors during six months, 9 are still alive today, while one patient was infected with HIV from a blood transfusion while undergoing an operation. The residual risk of the blood station using a statistical model and retrospective methods were 1/1,773 - 1/28,867 and 1/2,008 - 1/2,730 donations respectively. CONCLUSION: The residual risk of HIV after screening in the county blood station was high. We recommend further improvements to current blood screening practices.

AIDS Serodiagnosis↗
PubMed2000

[The survey of HIV prevalence among drug users in Guangxi, China].

OBJECTIVE: To understand the distribution and related risk factors of HIV infection among drug users in Guangxi. METHOD: Three hundred and twenty five drug users were tested for serum HIV antibody, with enzyme linked immunosorbent assay. RESULTS: One hundred and sixteen drug users (35.7%) were found to be HIV positive. The main risk factors associated with HIV infection were intravenous drug users and needle sharing among drug users. The HIV prevalence was 40.9% (114/279) among IDUs, and only 4.3% (2/46) among oral drug users. The phenomenon of sharing injecting equipment (76.7%) among intravenous drug users in Guangxi represents a very serious problem. CONCLUSION: There is a high risk of HIV infection among drug users in Guangxi. Prevention programs urgently need to be implemented.

Adolescent↗
PubMed2000

[The natural history of HIV infection among IDUs in Ruili, Yunnan province, China].

OBJECTIVE: To study the natural history of HIV infections among intravenous drug users. METHODS: Six hundred and twenty five HIV infected people in Ruili, Yunnan province were observed. Retrospective data was analysed combined with a cross - sectional survey. RESULTS: The number of death was 190 among 625 HIV - positive people. The cumulative death rate among HIV infected persons was 76.9 per 1,000 person - year, and the AIDS related death rate was 19.8 per 1,000 person - year. The median survival period of HIV infected persons was 9 years, and the median incubation period was about 8 years. CONCLUSION: Of HIV infected people in Ruili, the median survival and incubation period were shorter compared with those in the United States and Western Europe.

Adult↗
PubMed2000

[The epidemiological study of HIV infection among paid blood donors in one county of China].

OBJECTIVE: To observe the prevalence of HIV infection among paid blood donors and risk factors. METHODS: Selected the residents between 18 to 50 years old from two villages in one county of China in 1997. We observed the prevalence of HIV infection and keep following them to 2000. RESULTS: Nine hundred sixty-three residents were investigated and the prevalence of HIV was 1.8% (17/963). There were 88 paid blood donors among 963 interviewed subjects, the HIV prevalence was significantly higher (17.0% or 15/88) than those who didn't have the experiences of paid blood donations (0.2% or 2/875). Only one person out of 668 who were followed from 1997 to 2000 has converted to sero-positive, the incidence of HIV infection is 0.06 per 100 person-years. Nearly half of sero-negative and sero-positive people have the experiences of muscle injection. Among those with HIV-positive spouse, we found no one converted to sero-positive. The CD(4) count of those sero-positive people declined every year. HIV subtype and C2-V3 region sequence analysis were made for five HIV-positive people in 1998, the result indicated that all of them were infected with HIV-1 subtype B' and the genetic divergence rate was 2.4%. CONCLUSION: There was a high prevalence of HIV among paid blood donors in some regions, and paid blood (plasma) donations were the main risk factor for HIV infection. Although no evidence suggests that during the follow-up period the epidemic of HIV infection has spread locally, it still shall take measurements to prevent further transmission of HIV through paid blood donors.

Adolescent↗
PubMed2000

[Study on the biology feature and pathogenicities to silkworm of a microsporidium isolated from Barathra brassicae L].

A microsporidium (called as Bab-M) was isolated from Barathra brassicae L. captured from suburban vegetable plot of Guang Zhou. The spores were long-ovoid in shape and 4.02 +/- 0.36 microns x 1.99 +/- 0.36 microns in size. Immunologically the microsporidium shared spore surface specific antigen(s) with N. bombycis. The ultrastructure and life cycle of Bab-M were similar to that of N. b.. The rate of transovarian transmission was high. The initial conclusion was that Bab-M should be referred to as Nosema bombycis, but there was variation between them.

Animals↗
PubMed2000

[Construction of cDNA library of Mortierella and screening of delta 9 fatty acid desaturase cDNA sequence].

Mortierella species have potential for fermentative production of polyunsaturated fatty acids including gamma-linolenic acid, Arachidonic acid and EPA, etc. In order to clone genes encoding enzymes in the unsaturated fatty acid biosynthetic pathway, cDNA library of Mortierella was constructed using lambda gt 10 vector. Using cDNA encoding conserved region of delta 9 fatty acid desaturase gene as probe, Mortierella cDNA library was screened. After two rounds of screening one positive clone was identified which has insert length of larger than 1.6 kb.

Base Sequence↗
PubMed2000

[Practicability of IFAT using Plasmodium cynomolgi and Plasmodium falciparum antigens in different malarious areas].

OBJECTIVE: To compare the practicability of IFAT in different malarious areas using Plasmodium cynomolgi(P.c.) and Plasmodium falciparum(P.f.) antigens. METHODS: This survey was carried out in Yaliang Township of Sanya City, Hainan Province, where a mixed malaria is endemic, and in Tongbo County, Henan Province where only vivax malaria is endemic, and in Weihui City, Henan Province where vivax malaria has been under effective control since 1994-1998. RESULTS: In Yaliang Township, 310 blood samples were examined, the antibody positive rates with P.c. and P.f. were 37.4% and 31.3%, respectively, the rate of coincidence being 83.9%. In Tongbo County, 300 blood samples were examined. The antibody positive rates with P.c. and P.f. were 23.0% and 9.7%, respectively (P < 0.01). Another 245 blood samples from children were examined in Weihui City and the antibody positive rates were below 1% with two antigens, while the positive antibody rate was 3.3% with P.f. antigen. CONCLUSION: Both P.f. and P.c. antigens could be used in malaria antibody surveillance in mixted endemic areas, while in vivax malaria endemic areas, P.c. antigen was recommended.

Animals↗
PubMed2000

Study on stereometric parameters of optic nerve head of normal, big-cupped disk and glaucomatous eyes using Heidelberg retina tomograph.

PURPOSE: To investigate the difference of stereometric parameters of optic nerve head between the normal subjects and patients with big-cupped disk and primary open angle glaucoma(POAG). METHODS: Twenty-two cases (44 eyes) of normal subjects, 17 cases (34 eyes) of patients with big-cupped disk and 19 cases (37 eyes) of patients with POAG underwent Heidelberg Retina Tomograph (HRT) examination to get topography images and stereometric parameters of optic nerve head. RESULTS: The stereometric parameters of optic nerve head of the normal, patients with big-cupped disk and POAG were 1) disk area (mm2): 1.995 +/- 0.501, 2.407 +/- 0.661 and 2.248 +/- 0.498; 2) cup area (mm2): 0.573 +/- 0.264, 1.095 +/- 0.673 and 1.340 +/- 0.516; 3) cup/disk ratio: 0.257 +/- 0.095, 0.428 +/- 0.176 and 0.589 +/- 0.195; 4) rim area (mm2): 1.461 +/- 0.328, 1.312 +/- 0.418 and 0.905 +/- 0.409; 5) cup volume (mm3): 0.108 +/- 0.073, 0.347 +/- 0.346 and 0.550 +/- 0.394; 6) rim volume (mm3): 0.421 +/- 0.111, 0.378 +/- 0.225 and 0.224 +/- 0.189; 7) mean cup depth (mm): 0.225 +/- 0.070, 0.327 +/- 0.105 and 0.424 +/- 0.148; 8) maxim cup depth (mm): 0.630 +/- 0.178, 0.732 +/- 0.170 and 0.871 +/- 0.245; 9) cup shape measure (mm): -0.1867 +/- 0.09, -0.108 +/- 0.068 and -0.02 +/- 0.164; 10) mean RNFL thickness (mm): 0.290 +/- 0.053, 0.236 +/- 0.131 and 0.174 +/- 0.134; 11) RNFL cross sectional area (mm2): 1.419 +/- 0.332, 1.263 +/- 0.606 and 0.920 +/- 0.687. Besides, there was no difference of disk area between big cupped disk group and POAG group, no difference of rim area, rim volume and RNFL thickness between normal group and big cupped disk group, statistics analysis showed that there was significant difference of other stereometric parameters between the normal group and big cupped disk group or big cupped disk group and POAG group. CONCLUSIONS: There is certain difference of optic nerve head between the normal subjects and big-cupped disk and patients with POAG.

Adult↗
PubMed2000

[The Ahmed glaucoma valve implantation for refractory glaucoma].

OBJECTIVE: To evaluate the efficacy of the Ahmed Glaucoma Valve implant in the treatment of refractory glaucoma. METHODS: 28 cases(29 eyes) of refractory glacucoma were treated by the Ahmed glaucoma Valve implant, including 10 cases (10 eyes) of neovascula glaucoma, 5 cases (6 eyes) of juvenile glaucoma and 13 cases (13 eyes) of other causes glaucoma. RESULTS: Post-operative follow-up time was 3-12 months. The intraocular pressure (IOP) was lowered from preoperative 40.9 +/- 7.32 mmHg (1 mmHg = 0.133 kPa) to postoperative 20.63 +/- 2.75 mmHg in Neovascular glaucoma; from preoperative 41 +/- 5.66 to postoperative 18.00 +/- 2.12 mmHg in glaucoma after IOL implant combined with vitrectomy operation; from preoperative 33.65 +/- 5.28 to postoperative 16.45 +/- 1.48 mmHg in juvenile glaucoma; from preoperative 31.43 +/- 4.13 to postoperative 18.13 +/- 1.25 mmHg in the failure conventional filtering surgery of glaucoma. The postoperative complicatons were flat anterior chamber, hyphema, anterior iritis and so on. CONCLUSION: The Ahmed glaucoma valve implant is a useful method in lowing IOP of refractory glaucoma.

Female↗
PubMed2000

[Quantitative measurement of macular thickness in normal subjects by optical coherence tomography].

OBJECTIVE: To measure the thickness of retinal neurosensory layer, retinal pigment epithelium (RPE) and choriocapillaris in normal subjects by optical coherence tomography (OCT). METHODS: Sixty normal subjects (120 eyes) were examined by OCT with 4 mm scanning length horizontally and vertically through foveola. The mean thickness of retinal neurosensory layer, RPE and choriocapillaris thickness in foveola, 175 microns and 750 microns to foveola, were calculated and compared. RESULTS: The mean thickness of retinal neurosensory layer is 146.34 +/- 8.58 microns in foveola; 155.58 +/- 10.20 microns in 175 microns to foveola and 252.98 +/- 14.07 microns in 750 microns to foveola. The mean thickness of RPE and choriocapillaris is 106.26 +/- 10.58 microns in foveola; 104.98 +/- 7.24 microns in 175 microns to foveola and 106.84 +/- 9.95 microns in 750 microns to foveola. The results show that there are no significant in mean thickness of retinal neurosensory layer in 175 microns to foveola in statistics, but there are differences in 750 microns to foveola between nasal and temporal or superior, inferior and nasal, temporal. The differences in mean RPE and choriocapillaris thickness of all sites are not significant. Correlative analysis showed that there is no correlation between retinal neurosensory layer, RPE and choriocapillaris thickness and age. CONCLUSION: OCT can accurately measure the thickness of retina in normal eyes and provide a subjective and Quantitative method to diagnose macular diseases.

Adolescent↗
PubMed2000

[The synthesis and spectral study of multicomponent heteropoly compounds with Keggin structure].

The Multicomponent heteropoly compounds [Me4N]3 + x[PVxMoyW12-x-yO40]. n(H2O) with Keggin structure have been synthesized, and have been characterized by FTIR and NIR FT-Raman. The vibrational regularity of oxygen-containing bonds (P-Oa, M = Od, M-Ob-M and M-Oc-M) in these heteropoly compounds have been studied. The vibrational frequencies nu as (M = Od) and nu as (M-Ob-M) was shown to prove the reason why the acidity of the heteropoly compounds descended and the oxidization increased by the substitution of V atoms.

English Abstract↗
PubMed2000

[Study on the interaction of copper-zinc superoxide dismutase with cobalt(II)-tryptophane by spectral analysis].

The effect of changing the amount of external added Co(trp)n and pH values on the interaction of Cu2Zn2 SOD with organic metal compound (Cobalt(II)-Tryptophane) have been studied by means of ICP, VIS and measurement of enzyme activity. It has found that in aqueous solution, there exists a direct interaction of the metal ions of the active center in the metalloenzyme (Cu2Zn2 SOD) with external added Co(Trp)n. As a result, part of the metal ions in metalloenzyme were replaced and the corresponding metalloenzyme derivatives (Co(II)-substituted derivatives of SOD) were produced and the catalytic activity of enzyme were affected. It has also studied the intensity of interactions in different molar ratios (Cobalt(II)-Tryptophane) and pH values and got some results under the effect of corresponding factors.

Cobalt↗