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Biomedical subjects

C W Zhang

Publications and source records attributed to C W Zhang.

At least 19 recordsLinked to original sources
PubMed2001

Expression, purification, and characterization of recombinant HIV gp140. The gp41 ectodomain of HIV or simian immunodeficiency virus is sufficient to maintain the retroviral envelope glycoprotein as a trimer.

Efforts to understand the molecular basis of human immunodeficiency virus (HIV) envelope glycoprotein function have been hampered by the inability to generate sufficient quantities of homogeneous material. We now report on the high level expression, purification, and characterization of soluble HIV gp140 ectodomain proteins in Chinese hamster ovary-Lec3.2.8.1 cells. Gel filtration and analytical ultracentrifugation show that the uncleaved ADA strain-derived gp140 proteins are trimeric without further modification required to maintain oligomers. These spike proteins are native as judged by soluble CD4 (sCD4) (K(D) = 1-2 nm) and monoclonal antibody binding studies using surface plasmon resonance. CD4 ligation induces conformational change in the trimer, exposing the chemokine receptor binding site as assessed by 17b monoclonal antibody reactivity. Lack of anti-cooperativity in sCD4-ADA trimer interaction distinct from that observed with sCD4-SIV mac32H implies quaternary structural differences in ground states of their respective spike proteins.

Amino Acid Sequence↗
PubMed2000

[CT manifestation of pterygopalatine fossa in adult skull].

OBJECTIVE: The aim of this study was to measure certain diameters of the pterygopalatine fossa (PPF) and to discuss the anatomic appearance of PPF on CT images. METHODS: 20 dry skulls were scanned by CT on axial and coronal plane with 2 mm slice thickness. RESULTS: On CT imaging, the shape of superior 1/4 part of PPF is mainly shown as biconcavity. The maximal posteroanterial (PA)diameter was (6.6+/-2.2)mm. The maximal medialateral diameter (ML)was (13.7+/-3.7)mm. The shape of the middle 1/4 part of PPF was biconvexity with the PA and ML of (6.6+/-2.1)mm and (12.1+/-2.7)mm. The shape of the inferior 1/2 part of PPF just liked a tube with the diameter of (3.8+/-1.7)mm. The foramen rotudum lied (5.2+/-2.3)mm under the inferior orbital fissure. The pterygoid canal lied (7.4+/-2.5)mm medial and (6.2.+/-4.2)mm inferior to the foramen rotudum. CONCLUSION: PPF has various shapes on axial and coronal CT images. Based on the distances and the relationship between the foramen and fissures, the normal and abnormal status of PPF can be evaluated.

English Abstract↗
PubMed1997

[Properies of orthodontic wires in simulated teeth alignment test]

In this study,methods were developed to test and compare leveling archwires that commonly used in domestic practice.The results showed that the stainless steel arch wires were stiff.The Ni-Ti wires and the wires with loops were flexible and could deliver more constant force.The 0.014 Chinese Ni-Ti wires demonstrated the superelastic property,but 0.016 Ni-Ti wire did not appear the same property before they generated 250g force.

Journal Article↗
PubMed1997

[Orthodontic wires in a simulated oral environment:change in mechanical properties]

In this study,some different kinds of orthodontic archwires were tested to evaluate the changes of their mechanical properties.The results showed that in oral environment,all wires suffered degradation of their properties:the force-generating capacity decreased and the permanent deformation increased.The force-generating capacity decreased and the permanent deformation increased.The force decay resulted mainly from the tooth movement.The deformation occurred within 7 days.Chinese-NiTi alloy suffered less stress-relaxation and residual deformation than the stainless steel wires.Arch wires with vertical loops showed similar properties with NiTi,which could deliver more constant force.

Journal Article↗
PubMed1996

Microscopic observations on livers of rabbits and dogs infected with Schistosoma japonicum cercariae and early treatment with artemether or praziquantel.

UNLABELLED: To study the histopathological change of the liver of the hosts treated with artemether (Art) or praziquantel (Pra) in early stage after infection with Schistosoma japonicum cercariae. METHODS: Dogs infected once with schistosome cercariae were treated ig with Art 10 mg.kg-1 or Art capsule (ArtC) 15 mg.kg-1 on d 7, or praziquantel (Pra) 30-40 mg.kg-1 on d 21 after infection, followed by the repeated dosing once every 1 or 2 wk for 2-4 times. In rabbits, infected with 48-52 schistosome cercariae once every other day for 5 times, were treated ig with Art 10 mg.kg-1 or Pra 30 mg.kg-1 was started on d 7 or on d 21 after the first infection, followed by the repeated dosing every 1 or 2 wk for 2-3 times. RESULTS: After above mentioned dogs or rabbits were treated ig with Art, ArtC or Pra, the female worm reduction rates were 92.1%-100%. Histopathological examination showed that the reduction rates of total granuloma in the liver sections of the dogs and rabbits were 70.9%-97.3% and 76.5%-97.4%, respectively. Meantime, the structure of the hepatic lobules was normal with normal arrangement of the liver bundle. CONCLUSIONS: Early treatment with Art or Pra exhibited a promising effect of protection of the liver of the dogs and rabbits infected with schistosome cercariae. Early treatment of infection with schistosome cercariae kills the Female worms before oviposition. Thus, the host will be protected from the damage caused by schistosome eggs. Promising results were obtained when mice and rabbits received an early treatment with artemether (Art) or praziquantel (Pra). This work was to study the liver infected with cercariae and treated by intragastric gavage (ig) with Art, Art capsule (ArtC) or Pra in early stage after infection.

Animals↗
PubMed1991

[The detection of antibodies to Mycobacterium tuberculosis and its reactivity to three different purified protein derivative by ELISA].

The specific PPD IgG antibodies in serum of patients with pulmonary tuberculosis and its reactivity to PPD of Mycobacterium tuberculosis M. bovis and M. avium were detected by ELISA. The results showed that the antibody level and positive rate of patients with pulmonary tuberculosis significantly increased than those of normal subjects. Specific antibody level and its positive rate were higher in hospitalized patients than those treated in clinic and both were higher in sputum positive cases than in sputum negative one. There was cross-reactivity among three different PPD. Absorption black test indicated that M. tuberculosis PPD had good specificity. PPD should be further purified in order to make ELISA as a useful serodiagnostic tool.

Antibodies, Bacterial↗
PubMed1990

[Effect of mebendazole, albendazole and albendazole sulfoxide on glycogen contents of Echinococcus granulosus cysts in infected mice].

Mice infected with protoscoleces of Echinococcus granulosus for 8-9 months were treated ig with mebendazole (Meb) 50 mg.kg-1.d-1, albendazole (Alb) 300 mg.kg-1.d-1 or albendazole sulfoxide (AlbSO) 150 mg.kg-1.d-1 for 1-7 d. The glycogen contents of cyst wall in each drug groups were 1.0 +/- 0.6 - 1.8 +/- 0.9 mg/g, 1.1 +/- 0.9 - 1.8 +/- 0.8 mg/g and 0.8 +/- 0.5 - 1.5 +/- 0.9 mg/g, respectively, which were less than those 2.2 +/- 1.3 - 2.8 +/- 1.3 mg/g of corresponding control groups with respective glycogen reduction rates of 38-55%, 36-51% and 46-62%. After prolongation of treatment course to 10-14 d, the glycogen contents of cyst wall in Meb and AlbSO groups were further decreased, which resulted in glycogen reduction rates of 73% and 69%, respectively. No further decrease of glycogen contents in Alb groups was seen as the glycogen reduction rates sustained in 32%. Histochemical observation showed that the glycogen contents in germinal layer of the cysts decreased significantly or even disappeared during the treatment of Meb, Alb or AlbSO. The results suggested that the effects of Meb and AlbSO on mice infected with secondary cysts of E granulosus were superior to Alb as evaluated by glycogen reduction rate of cyst wall.

Albendazole↗
PubMed1989

[Quantitative study of airborne fungi at three functional sections of Chengdu city].

Airborne fungi are considered as one of the important causes of allergies throughout the world. The climatic conditions of Chengdu are suitable for the breeding of molds. We conducted monthly a quantitative investigation of the airborne fungi at three functional sections of Chengdu city from January to December, 1987. The results indicated that the concentration of fungal spores in the air was high through the year. The range of the concentrations of the airborne fungi was 870.37-7592.59 spores/m3, with two peaks in April and October. The first six dominant airborne fungi were yeast, Cladosporium, Penicillium, Aspergillus, Aureobasidium and Non-sporulating. Of Aspergillus flavus strains detected by fluorescence of agar medium under ultraviolet light 33.49% were aflatoxin-producing. The data show that the climatic and environment factors can affect the spread of airborne fungal spores in the air. The results of previous studies and present surveys are compared and the offence of airborne fungi and the significance of this survey are also discussed in this paper.

Air Microbiology↗
PubMed1989

[A serological survey of Legionnaires' disease in domestic fowls and animals in Chengdu area].

A serological survey of antibodies against Legionella pneumophila (Lp) serotypes in Chengdu area by microagglutination test showed that there were high levels of antibodies against serotypes Lp1 and Lp6 in healthy domestic fowls and animals (rabbits, pigs, chickens, ducks and geese). In rabbits, antibodies against serotypes Lp1-Lp6 were determined, showing positive rates (titer greater than or equal to 1:16) ranging 6.3-23.8%. Among them only the serotype Lp3 did not show any positive one. The highest positive rate was observed in pigs' anti-Lp6 (89.8%), significantly higher than those reported in America, Denmark and Nanjing, China. The results suggested that recessive infections of Legionnaires' Disease Bacterium might occur in domestic fowls and animals. So the epidemiological surveillance of Legionnaires' disease in animals, as well as in environment (water and soil) is of importance for the prevention in man.

Animals↗
PubMed1989

[Immunological humoral response in mice experimentally infected with Echinococcus granulosus, preliminary result of kinetic observation].

5 serological methods included latex agglutination test (LA), enzyme-linked immunoelectrotransfer blot (EITB), enzyme-linked immunosorbent assay (ELISA), dot-enzyme-linked immunosorbent assay (Dot-ELISA) and immunofluorescence antibody test (IFA) were used to trace the kinetic changes of the humoral response in NIH mice experimentally infected with protoscolex of Echinococcus granulosus. Results showed that Dot-ELISA and IFA were able to detect antibodies 2 wk after infection while ELISA, EITB and LA gave positive reactions 4 wk, 2 mos and 3 mos after infection respectively. Therefore Dot-ELISA and IFA were considered to be the most sensitive ones among the 5 methods used. All infected mice gave positive reactions at 8 and 12 mos but none of the normal control mice showed any reaction throughout the period of observation (Fig. 1).

Animals↗
PubMed1989

[Light and electron microscopic observations on effects of tribendimidin on cuticle of Necator americanus and small intestinal mucosa of infected golden hamsters].

Golden hamsters infected with Necator americanus were treated orally with a new anthilmintic tribendimidin (N, N'-[bis-4'-(1-dimethyl amino ethylidene amino)phenyl] 1,4-phenyene dimethylidyne amine) at a single dose of 150 mg/kg. One h after medication, some worms showed cuticular swelling, fusion of transverse striations and attachment of host leucocytes onto the worm's damaged cuticular surface. Four h post treatment, the cuticle revealed a moderate swelling or even erosion. Meanwhile, the ventral cutting plates appeared to be swollen. After 8-24 h, severe cuticular swelling, erosion and peeling in female worm tails and male copulatory bursa were seen. No increases in lesions in the small intestinal mucosa of infected golden hamsters were observed 4-8 h after medication.

Animals↗