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H J Zheng

Publications and source records attributed to H J Zheng.

At least 19 recordsLinked to original sources
PubMed2004

Assessment of genetic, antigenic and pathotypic criteria for the characterization of IBDV strains.

The aim of this work was the selection and comparison of representative infectious bursal disease virus (IBDV) strains. Nine strains of IBDV, isolated at different times and from different geographic regions of Europe and China, were characterized. Batches of all strains were prepared following standardized protocols and checked for the absence of contaminating viruses. Criteria used for their characterization were: (i) the nucleotide sequence of the VP2 variable region, (ii) binding to a panel of neutralizing monoclonal antibodies in antigen capture enzyme-linked immunosorbent assays, and (iii) virulence in specific pathogen free chickens after infection with a standardized number of median embryo infective doses. Based on the first two criteria, two of nine strains were classified as classical virulent (cv) IBDV (F52/70, Cu-1wt), and five as very virulent (vv) IBDV (849VB, 96108, HK46, GX, Harbin). Remarkably, although a clear-cut difference was demonstrable between European cvIBDV (F52/70 and Cu-1wt) and vvIBDV (849VB and 96108) strains, there was a continuum in the pathogenicity of Chinese vvIBDVs. Our results indicate the probable existence of differences in virulence within IBDV lineages determined on the basis of antigenic typing using monoclonal antibodies and the alignment of the VP2 sequences. This indicates limitations in the analysis of IBDV pathotypes based on the VP2 variable region and emphasizes that these criteria may not be sufficient for the classification of IBDV strains.

Amino Acid Sequence↗
PubMed2001

[A telemedical multilevel server network system].

Telemedicine is a hot research focus. When we develop the telemedicine system, we find that in China the network condition can not fit the demands of the transregional telemedicine service. In order to improve the poor conditions, we have designed a set of telemedicine system based on distributed multilevel server network model. The paper expounds the structure and the working process of the system, then goes into the technology details in realizing it, finally discusses some relative questions.

Computer Communication Networks↗
PubMed2001

[Purification of recombinant hEGF expressed in yeast Pichia pastoris and the study on its characters].

OBJECTIVE: To obtain recombinant human epidermal growth factor(hEGF) that can be used in animal experiments and clinical trial. METHOD: Chemically synthesized hEGF gene was expressed in Yeast Pichia pastoris and the secretory hEGF was purified by Phenysepharose 6 Fast Flow(high sub), Q-sepharose High Performance, and Superdex 30 chromatography, and its characters were studied by respective methods. RESULTS: The purified hEGF doesn't contain pyrogen, endotoxin, or yeast chromosome DNA and the purity reached 98%. The recombinant human EGF has correct molecular weight, pI, N-terminal amino acids sequences, peptide map, ultraviolet spectrum and well-biological activity. CONCLUSION: The purified hEGF is in accord with the requirements for animal experiments and clinical trial which provides the basis of preparing EGF agents for clinical test.

Animals↗
PubMed1997

Urine lipids in patients with a history of filariasis.

The presence of lipids in postprandial urine was assessed in 116 patients with a history of filariasis and 70 normal individuals using a biochemical autoanalyzer. Urinary triglycerides (TGs) ranging from 10 to 1955 mg/dl were detected in 13 individuals with a history of chyluria, including 3 with TG levels ranging from 233 to 1955 mg/dl and cholesterol levels of 6-35 mg/dl. Three patients who had a filarial history but without chyluria were also found to have urinary TGs (13-15 mg/dl) without detectable cholesterol. Neither TGs nor cholesterol were detected in the urine of normal individuals. Fluctuations in postprandial urine lipid contents were measured by time course determinations of urinary TG and cholesterol in 17 patients with filariasis and a history of chyluria, 16 patients with filariasis and hydrocele and 16 normal individuals. The level of urine lipid excretion was found to increase within 1-4 h postprandially, with urinary TG levels ranging between 7.8 and 1284 mg/h in eight patients and urinary cholesterol levels between 1.2 and 138 mg/h in seven patients with a history of chyluria. To evaluate the origin of the urine lipids in hematochyluria, fish oil containing 360 mg eicosapentaenoic acid (EPA) and 240 mg docosahexaenoic acid (DHA) was prescribed to a patient with hematochyluria. The excretion of EPA and DHA in urine was increased postprandially in the patient, similar to the elevation of urinary TG and cholesterol. The profile of fatty acids from urine samples showed it was of dietary origin. Our results suggest that postprandial urine lipids, especially TG, might be used as markers for the clinical evaluation of chyluria.

Adult↗
PubMed1997

Evaluation of recombinant chitinase and SXP1 antigens as antimicrofilarial vaccines.

Prior studies indicate that a microfilarial stage-specific chitinase is a possible candidate antigen for a transmission-blocking vaccine against Brugian filariasis. The antigen is a functional enzyme that progressively appears as microfilariae mature and become able to infect and develop in a susceptible mosquito vector. It is recognized by a monoclonal antibody that reduces microfilaremia in infected animals and by a subset of sera from infected persons who remain amicrofilaremic. Immunization of jirds with recombinant chitinase induced partial protection against microfilaremia resulting from subsequent infection with Brugia malayi, but did not reduce adult worm burdens. Vaccination was much less effective when administered during the prepatent stage of infection and was ineffective when given to microfilaremic jirds. The protective epitope appears to be located close to the carboxy terminus of the chitinase molecule. Immunization of jirds with SXP1, an antigen present in multiple worm stages, also reduced microfilaremia and, in some experiments, adult worm burdens, but hyperimmunization with a recombinant filarial myosin was not protective. These observations indicate that the relative timing of immunization and infection is an important factor in the efficacy of antimicrofilarial vaccines.

Animals↗
PubMed1994

[Clinical research on the treatment of acute leukemia with autologous bone marrow transplantation].

38 cases of acute leukemia were treated with autologous bone marrow transplantation (ABMT). The marrow was purged with hyperthermia of 42 degrees C in vitro for one hour in microwave. Twenty-two among them were AML (CR1). Sixteen were ALL (CR1). The mean age was 26 (10-43) years. All the patients were engrafted successfully after ABMT. Mean DFS was 21 (3-69) months. Four cases relapsed at 3 to 8 months after ABMT. Two patients with ALL developed central nervous system leukemia at 12 and 15 months respectively after ABMT. The DFS and probability of relapse at 5 years were 67.8% and 16.8% respectively for all patients.

Adolescent↗
PubMed1993

[Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine: immunological observation].

We compared the effect of a single dose of ivermectin (100 micrograms/kg) with that of a standard course of diethylcarbamazine (DEC) (6 mg/kg) on several parameters of the host's antifilarial immune response in 60 patients with bancroftian filariasis enrolled in a double-blind drug trial. All participants had measurable serum levels of antifilarial antibodies and parasite antigens. Drug-induced clearance of microfilaremia was associated with a temporary increase in HC11 antigenemia and a decrease in serum levels of antibodies to soluble filarial antigens. Antigenemia progressively declined in patients who remained a microfilaremic after treatment, but declined and then rose in persons with recurrent microfilaremia. Treatment triggered a sustained increase in serum levels of IL-1, IL-6, TNF alpha and IFN gamma in all patients. Although Ivermectin and DEC are believed to exert their antiparasite activity via different mechanisms, the same pattern of serological changes was observed in patients treated with either drug.

Animals↗
PubMed1992

[Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine. I. Clinical and parasitological observations].

We compared the efficacy of a single dose of ivermectin with that of a standard course of deithylcarbamazine (DEC) for the control of microfilaremia in 60 patients with banrroftian filariasis who had developed recurrent microfilaremia after each of three or more prior treatments with DEC. The study was done as a randomized, double-blind trial. Complete, but transient clearance of microfilaremia was observed in both treatment groups. One year later, recurrent microfilaremia was present in 7 patients treated with ivermectin and in 5 treated with DEC. Pretreatment levels of microfilaremia were significantly higher in patients who relapsed within one year after treatment than in those who remained amicrofilaremia. Side effects of either treatment were common but mild. Febrile reactions were more frequent in the ivermectin group: while localized reactions consistent with a flare up of acute filarial disease occurred mostly in the DEC group. We conclude that ivermectin is an effective and practical alternative to DEC for treatment of recurrent microfilaremia due to bancroftian filariasis.

Adolescent↗
PubMed1991

Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine. I. Clinical and parasitologic observations.

We compared the efficacy of a single dose of ivermectin with that of a standard course of diethylcarbamazine (DEC) for the control of microfilaremia in 60 patients with bancroftian filariasis who had developed recurrent microfilaremia after each of three or more prior treatments with DEC. The study was done as a randomized, double-blind trial. Complete, but in some cases, transient clearance of microfilaremia was observed in both treatment groups. At one year, recurrent microfilaremia was present in seven patients treated with ivermectin and in five treated with DEC. Pretreatment levels of microfilaremia were significantly higher in patients who relapsed within one year after treatment than in those who remained amicrofilaremic. Side effects with both treatments were common, but mild. Febrile reactions were more frequent in the ivermectin group; localized reactions consistent with a flare-up of acute filarial disease occurred mostly in the DEC group. We conclude that ivermectin is an effective and practical alternative to DEC for treatment of recurrent microfilaremia due to bancroftian filariasis.

Adolescent↗
PubMed1991

Efficacy of ivermectin for control of microfilaremia recurring after treatment with diethylcarbamazine. II. Immunologic changes following treatment.

We compared the effect of a single dose of ivermectin with that of a standard course of diethylcarbamazine (DEC) on several parameters of the host's antifilarial immune response in 60 patients with bancroftian filariasis enrolled in a double-blind drug trial. All participants had measurable serum levels of antifilarial antibodies and parasite antigens at the onset of the study. Drug-induced clearance of microfilaremia was associated with a temporary increase in HC 11 antigenemia and a decrease in serum levels of antibodies to soluble filarial antigens. Antigenemia progressively declined in patients who remained amicrofilaremic after treatment, but declined and then increased in persons with recurrent microfilaremia. Treatment triggered a sustained increase in serum levels of interleukin-1, tumor necrosis factor, and interleukin-6 in all patients studied. Although ivermectin and DEC are believed to exert their antiparasite activity via different mechanisms, the same pattern of serologic changes was observed in patients treated with either drug.

Adolescent↗
PubMed1991

Monitoring of filarial antigens in jirds and patients after treatment.

We developed a sandwich ELISA with monoclonal antibodies to monitor filarial antigens in animals and patients after infection and treatment. Levels of antimicrofilarial antibodies and parasite antigens were measured periodically in 40 B. malayi infected jirds. In all animals L3 HC11 antigen was detected earlier than Mf ES34 antigen, while antimicrofilarial antibodies appeared much more slowly. These serologic changes precede the onset of patent infections. After 3 courses of treatment with DEC and M170, the levels of parasite antigen in sera and of Mf in peritoneal cavities were monitored in 23 infected jirds. In 8 jirds Mf became negative, no adult worms were found in 7 jirds and a single degenerating female worm was present in 1 jird. ES34 and HC11 were undetectable in 8/8 and 6/8 necropsy sera. Mf persisted in 11 animals, 9 jirds were necropsied, 8 contained adult worms. Detectable levels of ES34 or HC11 antigen were present in 7/9 and 8/9 from these animals. In sham-treatment, few changes were noted in control animals. Thus, parasitological findings at necropsy are correlated with the results of antigen detection assay. We analyzed serial serum samples from 32 bancroftian microfilaremia collected 1-42 months after DEC therapy. Mf resolved rapidly in all treated individuals. ES34 disappeared faster than HC11, 3 months after treatment. Levels of ES34 and HC11 antigens remained detectable or rising after treatment in 8 and 10 individuals. Four patients' Mf recurred 20-42 months after treatment. These findings show that the remaining or a rise in serum levels of antigen after therapy predicts recurrent microfilaremia in patients and additional treatment is needed.

Animals↗
PubMed1991

Survival and infectivity of Brugia malayi microfilariae after cryopreservation.

Methods were studied for the cryopreservation of microfilariae of periodic Brugia malayi. RPMI-1640 tissue culture medium containing 6% dimethyl sulfoxide (DMSO) and 15% newborn calf serum was used as cryoprotectant. Samples were frozen slowly in the vapor phase of liquid nitrogen prior to emersion in liquid nitrogen (-196 degrees C). The freezing rate was -0.5 to -1.0 degrees C per minute, microfilariae remained viable for as long as, 212 and 375 days, survival rates were 94 to 98% and they were infective to Aedes togoi mosquitos. The infective larvae (L3) were obtained for 10-11 days after feeding at 28 degrees C room-temperature and the infection rate of L3 in test mosquitos was 22.4-30.6%. All DMSO should be removed from the freezing medium to restore microfilariae activity after freezing.

Aedes↗
PubMed1990

Comparison of Dot-ELISA with Sandwich ELISA in detecting circulating antigen in patients with bancroftian filariasis.

Dot-ELISA assay was compared with standard Sandwich ELISA in detecting parasite antigen in sera from patients with bancroftian filariasis. The same monoclonal antibody and the same serum samples were used in both assays. With Dot-ELISA, 67 of 70 serum samples from microfilaremic patients were positive at a dilution of 1:50. End titers ranged from 1:80 to 1:1 280. While with Sandwich ELISA, 64 of the 70 serum samples were positive at a dilution of 1:10. End titers ranged from 1:10 to 1:320. The specificity of both assays was over 91%, but their sensitivity was markedly different. Dot-ELISA could detect as little as 0.055 ng/ml microfilarial antigen added to normal human serum, whereas the lower limit of detection by Sandwich-ELISA was 10 ng/ml parasite antigen. An additional advantage of Dot-ELISA is that it does not require radioactivity or sophisticated equipment and, therefore, can be performed in virtually all filariasis-endemic areas.

Animals↗
PubMed1990

Comparison of Dot-ELISA with Sandwich-ELISA for the detection of circulating antigens in patients with bancroftian filariasis.

We compared the performance of a newly developed Dot-ELISA with that of a previously described Sandwich-ELISA to detect parasite antigens in sera from patients with bancroftian filariasis. The same monoclonal antibody and the same sera were used in both tests. In the Dot-ELISA, 67 of 70 sera from microfilaremic donors were deemed to contain filarial antigens when screened at a dilution of 1:50. End titers were 1:80-1:1280. With the Sandwich-ELISA, 64 of the same sera were positive at a dilution of 1:10 and 42 were positive at a dilution of 1:50. End titers were 1:10-1:320. The specificity of both assays was greater than 95%, but their sensitivity was remarkably different. The Dot-ELISA could detect as little as 0.055 ng/ml microfilarial antigen added to normal human sera, whereas the lower limit with the Sandwich-ELISA was 10 ng/ml parasite antigen. Additionally, the Dot-ELISA does not require radioactivity or sophisticated equipment and, therefore, can be performed in virtually all filariasis-endemic areas.

Animals↗
PubMed1990

Parasite antigenemia in untreated and treated lymphatic filarial infections.

To evaluate the merit of antigen detection assays as a tool to monitor the efficacy of chemotherapy for lymphatic filariasis, we serially measured antigen levels in sera from jirds infected with Brugia malayi and from humans with bancroftian filariasis. Antigenemia was detected in all animals with parasitologically proven infection and was present in jirds with prepatent or occult filariasis. Antigen levels correlated with worm burdens, and progressively declined in drug-cured animals. Treatment with diethylcarbamazine (DEC) triggered a transient increase in serum levels of filarial antigens bearing the epitope recognized by the monoclonal antibody HC 11. All patients with bancroftian filariasis became amicrofilaremic within one week after DEC treatment. Antigenemia levels slowly declined over a period of several months in all but one treated individual. Forty-two months after treatment, progressively rising antigen levels are present in 10 patients. Six of these remain amicrofilaremic; in the other 4, elevated antigenemia levels preceded or were detected at the same time as recurrent parasitemia. Periodic monitoring of antigenemia levels after treatment of patients with lymphatic filariasis can be used to identify individuals who are likely to develop recurrent microfilaremia before the parasites become detectable in blood samples, thereby allowing timely retreatment.

Animals↗