Biomedical subjects

Wei-ping Liu

Publications and source records attributed to Wei-ping Liu.

At least 55 records · Page 3Linked to original sources

PubMed2004

Effects of pesticides on soil biochemical characteristics of a paddy soil.

The impact of triazophos, bensulfuron-methyl, chlobenthiazone on soil biochemical characteristics in a paddy soil under controlled moisture (flooded soil) and temperature (25 degrees C) condition was studied. The electron transport system (ETS)/dehydrogenase activity displayed a negative correlation with triazophos, bensulfuron-methyl, chlobenthiazone concentrations, and the activity decreased as the concentration of the pesticides increased. The higher doses, 5 and 10 field rates, of triazophos, bensulfuron-methyl, chlobenthiazone significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect against the control. The relative toxicity of triazophos, bensulfuron-methyl, chlobenthiazone in decreasing the ETS activity was in the order: triazophos > chlobenthiazone > bensulfuron-methyl, irrespective of the rates of application. Triazophos, bensulfuron-methyl, chlobenthiazone caused an improvement in the soil phenol content and it increased with increasing concentration of triazophos, bensulfuron-methyl, chlobenthiazone. Triazophos, bensulfuron-methyl, chlobenthiazone incorporation did not produce any significant change in soil protein content. The response of biomass phospholipid content was nearly similar to ETS activity. The phospholipid content was decreased with the addition of triazophos, bensulfuron-methyl, chlobenthiazone in the order of triazophos > chlobenthiazone > bensulfuron-methyl; and the toxicity of applied amount was in the order: 10 FR (field rate) > 5 FR > 1.0 FR > 0.5 FR > control.

Agriculture↗

PubMed2004

[Detection of TCR-gamma chain gene rearrangement in malignant histiocytosis].

OBJECTIVE: To investigate the lineage of the malignant cells in malignant histiocytosis. METHODS: Polymerase chain reaction with two groups of common primers for TCR-gamma gene was used to analyze the malignant cells of 28 autopsied cases of malignant histiocytosis. RESULTS: Monoclonal TCR-gamma gene rearrangements were detected in 12 out of the 28 samples (43%). CONCLUSION: Most cases diagnosed as malignant histiocytosis in Southwest China seems to be peripheral T-cell lymphomas.

Adolescent↗

PubMed2004

[The expression of ALK protein and Epstein-Barr virus gene products in anaplastic large cell lymphoma and its significance].

OBJECTIVE: To investigate the characteristic of ALK protein expression in anaplastic large cell lymphoma (ALCL) and the relationship between ALCL and Epstein-Barr virus (EBV). METHODS: Histopathological method was used to study the morphological characteristic. Immunohistochemical staining was used to detect ALK protein and other antigen. EBV-encoded EBER was detected by in situ hybridization. RESULTS: All 2 cases of primary cutaneous ALCL were ALK protein negative. 20 cases of systemic ALCL were found to be ALK protein positive in 12 cases (60%), which included 8 cases of common variant, 3 cases of lymphohistiocytic variant and 1 case of small cell variant; the expression of ALK protein showed no significant difference between these 3 variants (P>0.05). The ALK protein expression pattern was characterized by the brown-stained nucleus and cytoplasm of the cells, but in 2 cases only the cytoplasm was stained. The patients with ALK protein expression were younger than those without ALK protein expression (P<0.05); all 22 cases were EBER negative. CONCLUSION: High incidence of the expression of ALK protein was seen in ALCL, especially in ALCL of younger patients. No relationship was observed between EBV and ALCL in this study.

Adolescent↗

PubMed2004

[Removal of turbidity and effect of humic acid in flocculation by polyferric chloride].

The removals of humic acid and turbidity by polyferric chloride under different coagulation conditions were studied (pH = 4, 7, 10). Zeta potential, turbidity and humic acid removal efficiency were analyzed. Experimental results showed that the dosage and scope of polyferric chloride (PFC) is the narrowest and the residual turbidity is biggest when pH = 4, the dosage and scope of PFC is the broadest and the residual turbidity is the least when pH = 10; Fe(III) can complex with humic acid under acidic condition; The effect of flocculation is not influenced by the presence of humic acid.

Chlorides↗

PubMed2004

[Reductive dechlorination of atrazine by Ni/Fe bimetallic particles].

Dechlorination of atrazine under acidic conditions was studied by using Fe and Ni/Fe bimetallic particles respectively for the confirmation of the catalytic role of Ni/Fe. Effect of pH value, Ni/Fe proportion and dosage of metal powder were discussed as well. The results indicated that Ni/Fe bimetallic particles was very effective for dechlorination of atrazine, with the dechlorination efficiencies above 90% by using 1.22% (W/W) Ni/Fe at pH value of 2.0 in 30 minutes, very superior to Fe particle with the dechlorination efficiencies only 22.21% in 90 minutes under the same conditions. By the comparison of the surface morphology of both Fe and Ni/Fe and experimental results, catalytic mechanism of Ni/Fe bimetallic particles was also proposed.

Atrazine↗

PubMed2004

[Study on glucocorticoid receptor alpha and beta in colonic mucosal cell of patients with ulcerative colitis].

OBJECTIVE: To investigate the relationship of the expression of GRalpha and GRbeta in the colonic mucosal cell of patients with ulcerative colitis to the efficacy of glucocorticoid (GC) therapy and the intensity of inflammation. METHODS: GRalpha expression and GRbeta expression in the colonic mucosal specimens were assessed by means of immunohistochemistry. Then comparative analyses were made on the GRalpha and GRbeta expression between the GC resistant group and GC sensitive group at various levels of inflammation. A normal response group was observed for comparison. RESULTS: The staining intensities of both GRalpha and GRbeta in colonic mucosal specimens showed significant differences between the GC resistant group, GC sensitive group and normal response group. No association between the expression of GRalpha and GRbeta and the degree of inflammation was found. CONCLUSION: These findings suggest that both GRalpha and GRbeta play an important role in the mechanism of the action of GC, and GRbeta functions as a dominant negative inhibitor of GRalpha in there. The expression of GRalpha and GRbeta in the colonic mucosal cell of patients with ulcerative colitis may serve as predictors of glucocorticoid response, but cannot be used as the markers of the severity of inflammation.

Adult↗

PubMed2004

[Mesorectal spread and circumferential margin involvement of rectal cancer studied on large slice].

OBJECTIVE: To provide the mode of cancer distribution in the mesorectum and circumferential resection margin. METHODS: Large slice technique was used in the pathologic study of 62 specimens operated on following the principles of total mesorectal excision (TME). RESULTS: More than 40% of all the observed neoplastic foci were located in the outer layer of the mesorectum in Stage III patients. Further analysis of the foci's localities with respect to the primary tumor's locality showed that ipsolateral neoplastic foci (44.44%) were significantly more than the contralateral neoplastic foci (13.33%) in the mesorectum (P<0.05). Extramural distal spread was found in 8 cases with the maximum extent of 3.5 cm. No significant difference in occurrence of circumferential margin involvement (CMI) was observed among tumors of different location, but tumors of poorer differentiation were noted to have a higher risk of CMI. CONCLUSION: Large slice technique offers a whole image of rectum, mesorectum, together with the position of neoplastic foci. There are outer preponderance and lateral discrepancy of neoplastic foci distribution in the mesorectum. A distal clearance margin of 4 cm would be mandatory. We advocate the adoption of TME as the baisc surgical principles in treating patients with rectal cancer and in avoiding surgery-related circumferential margin involvement.

Adenocarcinoma↗

PubMed2004

[Detection of ALK gene translocation by fluorescence in situ hybridization in paraffin-embedded anaplastic large cell lymphoma tissue and its significance].

OBJECTIVE: To compare the value of fluorescence in situ hybridization(FISH) with that of immunohistochemistry in detecting ALK gene translocations and ALK fusion protein in anaplastic large cell lymphoma (ALCL) and investigate the possibility of FISH working on paraffin-embedded ALCL tissue. METHODS: Dual-color FISH and ALK-1 immunohistochemistry were used to detect ALK gene translocation and ALK fusion protein in 22 paraffin-embedded ALCL cases. RESULTS: The digestion time of tissue section was a key-point in the operating of FISH in paraffin-embedded tissue. ALK fusion protein expression was detected with ALK-1 antibody in 12 of the 20 systemic ALCL; it was not detected in 2 primary cutaneous ALCL. The Dual-color FISH results were 100% consonant with the immunohistochemical results. CONCLUSION: (1) Generally, immunohistochemical method is the first choice in detecting ALK gene translocation, but when conditions permit, FISH can be the first choice. (2) By the optimization of experimental conditions, FISH can be successfully performed on paraffin-embedded tissue.

Anaplastic Lymphoma Kinase↗

PubMed2004

Photochemistry of insecticide imidacloprid: direct and sensitized photolysis in aqueous medium.

The direct and sensitized photodegradations of imidacloprid, 1-(6-chloro-3-pyridinylmethyl)-N-nitro-2-imidazolidinimine, were investigated in aqueous solution and with and without various photo-sensitizers. Results of the study revealed that the intensity of lamp-house and irradiation wavelength had significant effects on the photolysis of imidacloprid. Complete degradation of 20 mg/L imidacloprid in aqueous phase was observed in 40 min under ultraviolet( UV) irradiation system, suggesting the ultraviolet ray played significant role in direct photolysis of imidacloprid. The additions of various photo-sensitizers lead to improve the degradation efficiency of imidacloprid under the irradiation of black light fluorescent lamp. TiO2 was the most efficient in the photo-catalytic degradation of imidacloprid among other photo-sensitizers in used this study. However, addition of acetone inhibited the photolysis of imidacloprid under the irradiation of UV, indicating the occurrence of competition between acetone and imidacloprid for photos. Mineralization of the imidacloprid was examined to clarify the final photochemical degradation products of the insecticide which were CO2, Cl- and NO3-. Complete photo-oxidation of nitrogen to NO3- occurred very slowly via the intermediate formation of NH4+ and NO2-.

Imidazoles↗

PubMed2004

[Spectroscopic analysis of the interaction of ethanol and acid phosphatase from wheat germ].

Conformational and activity changes of acid phosphatase from wheat germ in ethanol solutions of different concentrations were measured by fluorescence spectra and differential UV-absorption spectra. The effect of ethanol on kinetics of acid phosphatase was determined by using the double reciprocal plot. The results indicate the ethanol has a significant effect on the activity and conformation of acid phosphatase. The activity of acid phosphatase decreased linearly with increasing the concentration of ethanol. Differential UV-absorption spectra of the enzyme denatured in ethanol solutions showed two positive peaks at 213 and 234 nm, respectively. The peaks on the differential UV-absorption spectra suggested that the conformation of enzyme molecule changed from orderly structure to out-of-order crispation. The fluorescence emission peak intensity of the enzyme gradually strengthened with increasing ethanol concentration, which is in concordance with the conformational change of the microenvironments of tyrosine and tryptophan residues. The results indicate that the expression of the enzyme activity correlates with the stability and integrity of the enzyme conformation to a great degree. Ethanol is uncompetitive inhibitor of acid phosphatase.

Acid Phosphatase↗

PubMed2004

[Simultaneous determination of four-components in mixed herbicides by modified target factor analysis-UV spectrophotometry].

In this paper, the modified target factor analysis-UV spectrophotometry method is established for simultaneous determination of paraquat CL, cyanzine, metolachlor and atrazine in mixed herbicides. The experimental results show that the recovery of each herbicide by MTFA is more accurate than by TFA. The recovery of paraquat CL ranges from 99.47% to 102.02%, of cyanzine 98.93%-102.75%, of metolachlor 98.13%-102.65% and of atrazine 97.42%-103.20%, with SD for the four components to be 1.16%, 1.84%, 1.84% and 2.55% respectively. All in all, the modified target factor analysis method can be used to determine accurately mixed herbicides which exhibits intrinsic interaction among components.

Acetamides↗

PubMed2004

[The reaction mechanism of metolachlor and S-isomer with urease].

The binding of metolachlor and S-Isomer to urease in aqueous solution was studied using UV difference spectrum and fluorescence spectrum. According to the results of the UV difference spectrum curve, the UV difference adsorption deltaA changed rapidly when herbicide concentration increased from 0.0 to 1.6 micromol x L(-1) x UV difference spectra were red-shifted and absorb-peaks became lower. It was shown that herbicide can quench the urease fluorescence mainly through a static quenching procedure. The binding constant K and the number of binding site n were calculated according to the fluorescence quenching results. For metolachlor, K = 1.49 x 10(3) L x mol(-1) and n was 0.84; for S-isomer, K=2.22 x 10(3) L x mol(-1) and n was 0.89.

Acetamides↗

PubMed2003

Characteristics of MnO2 catalytic ozonation of sulfosalicylic acid and propionic acid in water.

The characteristics of different types of MnO(2) catalytic ozonation of sulfosalicylic acid (SSal) and propionic acid (PPA) have been investigated in this paper. The experimental results show the dependence of catalytic activity of MnO(2) on organic compounds and the pH of solutions, but it is independent on the type of MnO(2). For example, three types of MnO(2) have not any catalytic activity when ozonation of PPA under the condition of this experiment. All MnO(2) catalytic ozonation of SSal at pH=1.0 have a greater total organic carbon removal than ozonation alone has, however, at pH=6.8 and 8.5, catalytic efficiency is not observed. Furthermore, the batch experimental results indicate that there are no direct relationship between the activity of metal oxide catalytic decomposition of ozone and that of its catalytic degradation of organic compounds.

Benzenesulfonates↗

PubMed2003

[The aquation of oxaliplatin and the effect of acid].

AIM: To investigate the aquation of oxaliplatin in aqueous solution at different temperatures and gain the kinetic data. METHODS: Electronic conductometry and high performance liquid chromatography (HPLC) were used to measure the oxaliplatin content in the reaction systems at different time. RESULTS: The aquation of oxaliplatin followed a pseudo-first-order rate law. In the absence of H+, the observed rate constant kobs was 7.76 x 10(-6).min-1 and the half life t1/2 was 62 days at 25 degrees C. In the presence of H+, the aquation could be accelerated by H+ according to the equation kobs = (2.61 + 21.9 [H+]) x 10(-4).min-1. The mechanism of aquation has also been proposed in this paper. From the mechanism, the rate of aquation following to r = (k1 k2) [l-OHP]/k-1 in the absence of H+ and r = (k1 + K0k3 [H+]) [l-OHP] in the presence of H+ have been deduced, which were in perfect agreement with the experimental results. CONCLUSION: In the absence of H+, the aqueous solution of oxaliplatin is stable, which meets to the request of clinical.

Acids↗

PubMed2003

[Clinical analysis of brain injury in patients injured by high voltage electricity].

OBJECTIVE: To explore the pathogenic characteristics and management of brain injury in patients injured by high voltage electricity. METHODS: One hundred and thirty eight patients injured by electricity were enrolled in this study. Postburn brain injury was diagnosed by clinical sighs and imaging analysis. The brain injury was graded as mild, moderate, severe and most severe. The relationships among the inlet of the electric current and the electric voltage and the degree of brain injury were analyzed, and the causes and pathogenesis of the brain injury were suggested. Treatment modality was optimized for the patients according to the diagnostic data. RESULTS: In this group of patients, brain injury was identified in 106 cases, mostly rated as mild and moderate. Only 4 cases were ranked as severe degree with positive imaging findings. The electric voltage seemed to be not correlated with the incidence of postburn brain injury. But the intensity of electric current and the locations of electrical current inlet and outlet were closely related to the degree of brain injury. Among all the patients in this group, 131 survived and 7 died after treatment. But there was no death due directly to brain injury. CONCLUSION: There was high incidence of postburn brain injury in patients injured by high voltage electricity. The injury might be related to the direct effect of electrical current on the brain tissue, to mechanical injury, to the cardio-pulmonary lesions caused by electrical current, or to massive skin burn. Early and accurate diagnosis of the injury was of key importance for lowering both mortality and disability.

Adolescent↗

PubMed2003

Adsorption and correlation with their thermodynamic properties of triazine herbicides on soils.

Adsorption of atrazine, prometryne and prometon was determined on six soils with different physical and chemical properties. The adsorption isotherms of three herbicides could well fit Freundlich equation. On all of six soils, adsorption of herbicides increased in the order: atrazine approximately = prometon < prometryne. This order is quite the same to the calculation result of by means of excess thermodynamic properties of triazine. The Freundlich adsorption constants, Kf, showed to have good correlation with organic matter (OM%) of soils for each of these herbicides, suggesting that OM is the main factor, which dominates in the adsorption process of these triazine herbicides.

Adsorption↗

PubMed2003

[A pathologic analysis on 9,666 cases of tumors of nose, pharynx and throat].

OBJECTIVE: To analyze nasal, pharyngeal and laryngeal tumor patients age, sex and tumors' sites, to find out the relationship of above indices and tumor's pathologic types. METHODS: 9,666 cases of tumors on nose, pharynx and throat diagnosed in West-China Hospital in 1984 to 1999 were analyzed for the constitution of histological type. RESULTS: 1. the ratio of benign and malignant tumor is 1:8.6, it is 1:62.0 in nasalpharynx; 2. papilloma, angiofibroma and angioma are more commonly seen in all 21 kinds of benign tumors; 3. differentiated squamous cell carcinoma, non-keratinized is the most common types in 25 kinds of malignant tumors, the ratio of carcinoma and sarcoma is 11.98 to 1; 4. The average age of patients with malignancy is about 10 years older than that of the patients with benign tumors, and malignant patients are male predominant; 5. squamous cell papilloma of oralpharynx was the most common in all benign tumors; nasopharyngeal carcinoma is the most common in all malignancies, nasal lymphomas are the most common seen sarcoma. CONCLUSION: The histologic types of nasal, pharyngeal and laryngeal tumors are related with patients' age, sex and sites of tumors.

Adolescent↗

PubMed2003

[Study on the status of cell differentiation in nasal NK/T-cell lymphomas].

OBJECTIVE: To evaluate the status of cell differentiation in nasal NK/T cell lymphomas. METHODS: The clinical data of 88 cases of NK/T cell lymphomas were collected. Antibodies to the following antigens were used in the immunohistochemical study: T cell differentiation antigens (CD3epsilon, CD5 and CD1a); NK cell associated antigens (CD56, CD57) and antibodies of CD34 and CD38. RESULTS: (1) Clinicopathology: clinically, frequently involved sites were the nasal cavity and the pharynx. Ulceration and erosion of the mucosa were common signs. Pathologically, diffuse infiltration of the tumor cells was observed in 68 of 88 (70.45%) cases of nasal NK/T cell lymphomas. In 71 (80.68%) cases infiltrated cells were predominantly medium to large sized; (2) Differentiation status of tumor cells: the tumor cells expressed CD3epsilon in 78/88 (88.64%); CD5 in 56/88 (63.63%), CD56 in 25/88 (28.41%) and no positivity for CD1a, CD57, CD34 and CD38. CONCLUSION: Status of tumor cell differentiation in nasal NK/T cell lymphoma may have passed the stage of progenitor cell differentiation but not yet to the stage of mature T or NK cells.

Adolescent↗