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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 757 records · Page 42Linked to original sources
PubMed1997

[Corneal topography analysis before and after photorefractive keratectomy].

OBJECTIVE: To study the change of corneal surface morphology before and after photorefractive keratectomy (PRK) and analyze the decentralization of the ablation. METHODS: Corneal topography was examined on 122 eyes of 80 cases with myopia by computer-assisted photokeratography before and after PRK. RESULTS: Before PRK, the corneal topography of most examined eyes (75.4%) was symmetric bow tie pattern or asymmetric bow tie pattern; after PRK, the corneal topography of the ablated regions was mainly round or approximately round (63.9%). There is no relationship between the distance of decentralization of the ablation site and preoperative refractive diopters. But the more is the distance of decentralization, the more is the increase of postoperative corneal astigmatism and also the more is the decrease of the best corrected visual acuity. CONCLUSION: Examination and analysis on the corneal topography before and after PRK can clearly display the changes of the corneal surface morphology, and also can quantitatively evaluate the decentralization.

Adult↗
PubMed1997

[Effects of the double chamber intra-aortic balloon pumping on the renal circulation].

The effects of the double chamber intra-aortic balloon (DIAB) and the single chamber intra-aortic balloon (SIAB) on the hemodynamic parameters in the kidney were studied. No negative effect of both cases was observed. Before and after removing the renal nerve system, the DIAB was used and the results had been compared. The pulse produced by pumping activized the renal nerve system and reduced the renal vascular resistance. Therefore the reduction of the renal vascular resistance is an important reason for increasing the renal blood flow during intra-aortic balloon pumping.

Animals↗
PubMed1997

[Complications of osteotomy of vertebral arch and body in kyphosis].

Among total 67 postoperative complications resulted from osteotomy of vertebral arch and body in 439 cases of kyphosis, massive bleeding accounted for 2 cases (0.46%); spondylolisthesis, 6 (1.37%); paraplegia caused by compressing of the spinal cord, 5(1.14%); root pain, 6(1.37%); loss of correction, 26(29.55%); leaking and subcutaneous accumulation of CST, 5(1.14%); incision necrosis, 16(3.64%); lifting of luque rod with peneatration through the skin, 1(0.23%). Causes, treatment and prevention of these complications have been discussed in this study. We emphasize that the operation should be done after the stable of ankylosing spondylcitis. The degree of correction by osteotomy at one-level should be limited.

Adolescent↗
PubMed1997

[Callus formation of Aristolochia tuberosa and determination of aristolochic acid of callus by HPLC].

Studies on the callus induction starting from the young stems of Aristolochia tuberosa on MS medium were reported and the morphological characteristics of cultured cells were described. The results of HPLC determination showed that some callus cultures had higher aristolochic acid content than their original plant organs, and the callus cultured in MS medium +2, 4-D 0.5 mg/L produced more amounts of airstolochic acid(0.27% of dry callus weight) compared to the original plant organ (0.15/1000 of dry weight).

Aristolochic Acids↗
PubMed1997

[Immunohistochemical study of hepatitis C virus core antigen and HBxAg in liver cirrhosis and hepatocellular carcinoma tissues].

OBJECTIVE: To study the distribution and significance of hepatitis C virus core antigen in liver cirrhosis and hepatocellular carcinoma tissues. METHODS: Hepatitis C virus antigen and HBx-Ag were detected in liver cirrhosis (LC) and hepatocellular carcinoma (HCC) tissues with immunohistochemical methods. RESULTS: In some cases, not only was HCV core antigen positive stain distributed in the liver cells and nuclei of the cancer cell but it was also found in the cytoplasm. In different cases, it may be predominantly cytoplasm positive or nuclear positive or both. In liver cancer tissues, the HCV core antigen cytoplasmic positive cells were focally distributed and whereas the nuclear positive cells were diffusely distributed. The HCV core antigen nuclei positive cells were often observed in HCC tissues, but the cytoplasmic positive cells were often observed in the pericancerous liver tissue. The detection rates of HCV core antigen in LC, HCC and pericancerous liver tissues were 67.3% (66/98), 75.0% (78/104) and 48.1% (25/52), respectively. Statistical analysis suggested that: HCV core antigen nuclei positive rate in HCC be much higher than that in LC and pericancerous liver tissues (P < 0.01) and HCV core antigen nuclei positive rate be much higher than the cytoplasm positive rate in HCC tissues (P < 0.01). CONCLUSION: HCV, of which the infection being very common in LC and HCC of our country, may play an important role in the development of LC and HCC except HBV infection.

Carcinoma, Hepatocellular↗
PubMed1997

[Damage-loss relationships and integrated control of 3rd instar larvae of Actias selene nigpoana Felder in planting area of Cornus officinalis Sieb. et Zucc].

In the present paper, the damage-loss model of Actias selene ningpoana to Cornus officinalis was tested and the results indicated that the yield loss rates obeyed the equation Y = 100 - EXP(4.6042 - 0.0315X). The economic threshold of the 2hd and 3rd instar larvae of A. selene nigpoana was then determined as 22 and 8 insects per tree respecitively. Suggestions for integrated control have been made based on the research of activities of A. selene ningpoana in the forest.

Animals↗
PubMed1997

[Pathological analysis and clinical importance of invasion and neck nodal metastasis in squamous cell carcinoma of the tongue].

To determine the absolute and relative of histopathological parameters and conventional indicators in correlation with invasion and nodal metastasis, we performed both univariate and multivariate statistical analysis in 92 patients with squamous cell carcinoma of the tongue by spss/pc+ statistical system. Mode of invasion (MI) and peritumoral lymphocytic infiltrating density (PLID) were significant and independent factors by multivariate analysis (P = 0.000, P = 0.009 respectively), although univariate analysis showed that MI, PLID, T-stage and Grading were significantly associated with nodal metastasis. A correlation exists only between T-stage and MI by multivariate statistical test (P = 0.045), while, PLID, T-stage and Grading were significant parameters by univariate analysis. A highly dense PLI around cancer nest was observed which blocked nest from tissue and capillary lymph vessels.

Adult↗
PubMed1997

[An experimental study on the effect of xenogeneic bone combined with human recombinant bone morphogenetic protein-2].

OBJECTIVE: To determine the ability of a new type of composited xenogeneic bone to repair the bone defect. METHODS: The new type of composited xenogeneic bone was obtained by combining the treated cancellous bone with recombinant human bone morphogenetic protein-2 (rhBMP-2) and was implanted in the bone defect of rabbit. RESULTS: There were a large amount of new bone formation within the combined material and the amount was increasing as the time lapsed in the area of the bone defect. In contrast, there were a lot of fibrous tissues with a little new bone formed when the treated cancellous bone was implanted alone. CONCLUSION: The results imply that the rhBMP-2 plays a very important role in new bone formation and the composited xenogeneic bone appears to be an ideal material for the repair of bone defect.

Animals↗
PubMed1997

[Myocardial cells action potential and contractive function in hemorrhagic shock in rabbits].

Anesthetized rabbits were subjected to a moderate degree of hemorrhagic shock. Lowering their mean arterial pressure to 5.3 KPa for 3 h, we measured the mean arterial pressure (MBP), left ventricular systolic pressure (LVSP), left ventricular maximum velocities of contraction (dp/dtmax), and myocardial electrical activity. The results of this study demonstrated that LVSP declined in parallel with MBP; that dp/dtmax dropped acutely on the instant of hemorrhagic shock; dp/dtmax went up by 48% on 15 min after shock; then dp/dtmax fell gradually, and by 3 h after shock the dp/dtmax values dropped to 20% of the baseline values; that intracellular sodium and potassium contents increased significantly in the hemorrhagic shocked rabbits; that myocardial resting potential (RP) and action potential amplitude (APH) diminished; and that action potential duration(APD), action potential repolarized 50% duration (APD 50), and repolarized 90% duration (APD 90) were markedly prolonged in the hemorrhagic shock, compared with control. The results suggested that in hemorrhagic shock myocardial cells fast sodium channel was closed while slow sodium and slow calcium channels, were opened; thus sodium and calcium infused and potassium exuded.

Action Potentials↗
PubMed1997

[Physical analysis on living tissues' thermal injury process].

In the light of solid mechanics as well as thermal physics, the physical factors causing thermal injury are correlated and a new thermomechanical model is established to quantitatively describe the injury process in living tissues under heat striking. The three-stage mode of thermal injury to living tissue is interpreted. The paper reflects our preliminary effort to further study this clinical phenomenon in point of micro mechanics and thermal science. It is of significance in revealing the mechanisms of subcutaneous bubble formation, development as well as tissue's thermal mechanical disruption.

Biophysical Phenomena↗
PubMed1997

[A study on the counteracting effect of hypoxia and Qigong on simulated weightlessness and orthostatic tolerance after bedrest].

-6 degrees head down bed rest (-6 degrees HDBR) 21d were used to simulate weightlessness. 15 healthy males, aged 19-22, were divided into 3 groups with 5 people in each group: control group (-6 degrees HDBR), hypoxia group (-6 degrees HDBR + Low Oxygen), Qigong group (-6 degrees HDBR + Qigong). The results showed that the reduction of weight, perimeter of shank, daily average cardic output, basal cardic output and the pulse pressure of the Qigong group were lower than those of the control group (P<0.05). The basal cardic output and the perimeter of shank of the Hypoxia group reduced significantly than those of the control group (P<0.05). However, the reduction of the other physiological functions of the Hypoxia group were not significantly lower than that of the control group (P>0.05). During HUT +75 degrees 20 min orthostatic tolerance test after HDBR, the parameters in the Hypoxia group were better than those in the other groups. The average standing time was also longer, and no presyncopal symptom occured.

Adaptation, Physiological↗
PubMed1997

[Study of the relationship between human quality and reliability].

To clarify the relationship between human quality and reliability, 1925 experiments in 20 subjects were carried out to study the relationship between disposition character, digital memory, graphic memory, multi-reaction time and education level and simulated aircraft operation. Meanwhile, effects of task difficulty and enviromental factor on human reliability were also studied. The results showed that human quality can be predicted and evaluated through experimental methods. The better the human quality, the higher the human reliability.

Aviation↗
PubMed1997

[Observation of EGG parameters during -6 degrees head-down bedrest for 21 days].

Electrogastography (EGG) was recorded in 15 healthy volunteers before and after meal during 21 days head down tilt -6 degrees bed rest. The results showed that nausea, distension and pain in the abdomen and loss of appetite appeared at the beginning of bed rest and body weight decreased significantly (P < 0. 01) after bed rest; Low frequency (Bradygastria) proportion of EGG (<2.4cpm) increased apparently after 8 days of bedrest, and there was significant difference (P <0.05) between preprandial and postprandial bradygastria. The dynamic parameters of bradygastria declined significantly and the rhythm of bradygastria increased with duration of bedrest. It indicates that simulated weightlessness may cause decrease of gastric rhythm and gastric motility.

Aerospace Medicine↗
PubMed1997

[A prospective study on transfusion-related hepatitis C virus infection].

64 cases of blood recipients were followed-up for 6 months to study infection of hepatitis C virus. The infection rate of hepatitis C virus was 18.75% in total, including 8 cases of post-transfusion hepatitis C (PT-HC), 1 case of subclinical PT-HC, and 3 cases of anti-HCV sero conversion only. The time of initial ALT abnormality and anti-HCV sero conversion were 28 to 91 (51.9 +/- 20.9) days and 23 to 76 (42.4 +/- 15.9) days after blood transfusion respectively. There were 2 cases with cytomeglovirus infection and another 5 cases with unknown infectious agent were found in this study.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

[Determination of solanesol in the extracts of tobacco leaves by high performance liquid chromatography (HPLC)].

Solanesol, a terpene compound mainly isolated from tobacco, is an important intermediate of medicines such as vitamin K2 and coenzyme Q10. This paper presents an HPLC method for the determination of solanesol in the extracts of tobacco leaves. Solanesol is separated completely on a Zorbax-SIL column, 250 mm x 4.6 mm i.d., by using a mixture of n-hexane, isopropyl ether and ethyl acetate (6:3:1) as mobile phase and determined refractometrically. The isopropyl ether makes the chromatographic peak sharp and the addition of ethyl acetate can prevent the column from blockade during the analysis, and the appropriate temperature (30 degrees C) is beneficial to the shortening of analysis time. This method is fast, accurate and reproducible. It has good linear relationship in the range of 0.2-4 microg. The results have shown that the average recovery is 96.4% and coefficient of variation is 2.8%.

Chromatography, High Pressure Liquid↗
PubMed1997

[The spectrum analysis of high performance liquid chromatographic peak by ultraviolet-visible spectrophotometric detectors].

In the analysis of high performance liquid chromatography (HPLC), the qualification of chromatographic peak can be carried out by the methods of adding standard, comparing retention time and absorption spectrum etc. This paper reports a simple and practical method for measurement of absorption spectrum of HPLC peak by ultraviolet and visible variable wavelength detector. A BASIC program was edited with Shimadzu C-R4A data processor. Stopping the pump at the retention time we use the program to analyse absorption spectrum of the peak and the absorption spectrum of standard (Cr, PU, UA) by Shimadzu UV-2201 UV-VIS recording spectrophotometer and the absorption spectrum of standard (-S) with sample (-T) by this method are presented. The figure shows that the absorption spectra of the samples of Cr, PU and UA almost completely overlapped with those of the standards. The results showed that this method is reliable.

English Abstract↗
PubMed1997

[Studies on the chemical constituents of the alga Sargassum carpophyllum J. Agardh].

The alga Sargassum carpophyllum J. Agardh collected from the South China Sea was immersed in 95% ethyl alcohol. The combined extract was partitioned between ethyl acetate and water. The ethyl acetate phase was subjected to pressure-reduced chromatography over Silica H, eluted with a step gradient of EtOAc in petroleum ether. Two main fractions of sterols (I) and fatty acids (II) were obtained. The composition of I and II were identified by GC/MS. The fraction Ia was obtained, as a main composition of I, by repeated flash chromatography. On the basis of spectroscopic analysis, Ia was identified to be fucosterol.

Fatty Acids↗