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Table of Content

    28 February 1993, Volume 11 Issue 1
    DIFFERENTIATION OF SCHISTOSOME SPECIES AND STRAINS BY DNA HYBRIDIZATION
    1993, 11(1):  1-5. 
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    Genomic DNA from Schistosoma mansoni and S. japonicum adult worms was hybridized to a 32p-labelled pSM 889 probe after cleavage by restriction endonuclease BgIII, BamHI, Xbal and EcoRI, or to a 32p-labelled pSM389 probe after cleavage by EcoRI. The resulting hybridization banding patterns were significantly different between the two species. Genomic DNA from S. japonicum adult worms of Hunan, Hubei, Jiangxi, Zhejiang and Yunnan isolates was hybridized to a 32p-labelled pSM389 probe after cleavage by EcoRI. The major hybridization bands were identical while the minor bands were more or less different among the isolates. Of them,isolates Hunan, Hubei and Zhejiang have similar minor bands while isolates Jiangxi and Yunnan have minor bands significantly different from those of the above three isolates and also markedly distinct from those of each other. These results indicate that the major hybridization banding patterns are unique to schistosome species while the minor banding patterns may serve as the basis for strain differentiation.
    STUDIES ON THE STRAIN DIFFERENCES OF SCHISTOSOMA JAPONICUM IN THE MAINLAND OF CHINA XII. DNA HYBRIDIZATION OF FIVE ISOLATES
    1993, 11(1):  6-8. 
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    The nonradioactive labelled probe pSM889 was hybridized to Southern blots of genomic DNA of five isolates of Schistosama japonicum from Anhui, Hubei, Guangxi, Sichuan and Yunnan in the mainland of China. The major bands of hybridization of DNA digested by restriction endonucleases EcoRI and BamHI are same among the five isolates, but the minor bands of hybridization of DNA digested by EcoRI show some differences between 4. 4-9. 6 kb and between 2. 3-4. 4 kb among the five isolates. The result shows that the five isolates are of some genetic variation. It provides, at molecular level, evidence of the existence of different strains of 5. japonicum in the mainland of China.
    EFFECT OF SCHISTOSOMA JAPONICUM INFECTION ON LIVER DRUG-METABOLIZING ENZYMES OF MICE
    1993, 11(1):  9-11. 
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    In this paper, the effect of Schistosoma japonicum infection on liver drug-metabolizing enzymes of mice was studied. The prolongation of hypnosis duration of sodium pentobarbital in vivo and the inhibition of liver aniline hydroxylase (AH), aminopyrine N-demethylase (APD) as well as cytochrome P-450(Cyt P-450) in vitro were observed in mice infected with 20,40 and 60 cercariae of S. japonicum after 6 weeks. Meanwhile, with 30 cercariae infection, no significant inhibition of the activity of AH, APD and Cyt P-450 was observed in mice 4 weeks after infection, but significant inhibition of these enzymes was shown by 8 weeks . As compared with control , the activity of AH , APD and Cyt P - 450 decreased to 32. 6%, 13. 7% and 7. 7% at 8 weeks. The results indicate that infection of S. japonicum can inhibit the liver drug-metabolizing capacity of mice, and the degree of inhibition depands on the infectivity and the duration of infection.
    SCREENING ANTIHYDATID DRUGS USING CULTIVATED GERMINAL CELLS OF ECHINOCOCCUS GRANULOSUS1
    1993, 11(1):  12-16. 
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    Germinal cells isolated from Echinococcus granulosus cysts harbored in mice have been maintained in an in vitro culture system containing RPMI 1640 supplemented by 20% calf serum, and used as a model for screening antihydatid drugs. When the germinal cells were maintained in the medium for 6 days, the cell proliferation rate was rather high in the first four days but declined in the last two days. In screening drugs, 1. 4× 106 germinal cells were exposed to known effective drugs against metacestodes of E. granulosus in mice, such as mebendazole (Meb) ,albendazole (Alb) or praziquantel(Pra) at various concentrations. One to three days after exposure, cell counts were made daily in 3 samples of each drug concentration. The mean cell number of each group was compared with that of the control and the inhibition rate of the cell was then calculated. The results showed that the minimal effective concentrations of Meb, Alb and Pra, were 1. 0(48h),2. 5(24h)and 10. 0(72h)μg/ml, respectively,while the inhibition rates of the cell were 34. 1,55. 7 and 18. 5%. Interestingly, the in vitro effects of Meb, Alb and Pra were consistent to those obtained from the in vivo tests, ie MebAlbPra. Nevertheless, after exposure of germinal cells to Meb at 2. 5μg/ml for 24h, the cells appeared in roughness, indistinction, shrunk or swelling, collapse, deformation and hole - like feature detected by light microscopy and scanning electron -microscopy , while the ultrastructure alterations of the cells noted by transmission electron -microscopy were lysis in cytoplasm, disruption or disappearance of nucleus and even darkness of the whole cell.Another 11 kinds of compounds included fenbendazole, flubendazole and oxibendazole had been passed through the abovementioned in vitro system. Only the drugs (such as fenbendazole, flubendazole and E8824) exhibited effect against hydatid cyst in mice also showed the in vitro effect on the germinal cells.The good correlation between the in vitro and in vivo tests indicates that the in vitro system may be used for screening antihydatid drugs.
    VARIATIONS OF FREE AMINO ACIDS IN HEMOLYMPH OF CULEX PIPIENS FALLENS DURING OVERWINTERING PERIOD
    1993, 11(1):  17-20. 
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    An analysis of the amino acids present in the hemolymph of Culex pipiens pallens caught from resting or overwintering places (blood meal: Sella 1, i.e. empty; ovary stage: under Christophers IIb) in Zhengzhou (34°43'N,113°39E) indicated that 19,18 and 18 kinds of free amino acids (FAAs) were detected during stages of preoverwintering,overwintering and pos-toverwintering respectively. Comparison of hemolymph amino acids between overwintering and preoverwintering stages revealed that the concentrations of the total FAAs and FAAs reduced significantly in overwintering except cystine and proline. The concentrations of cystine and proline during preoverwintering were 0. 1563 ±0. 0021 nmol/μl and 22. 2467 ±1. 3537 nmol/μl, but 0. 2067±0. 0058 nmol/μl and 36. 5467 ±0. 4654 nmol//μl during overwintering respectively. Comparison of hemolymph amino acids between postoverwintering and overwintering stages showed that the concentrations of all FAAs and total FAAs increased significantly during postoverwintering stage, and the concentrations of aspartic acid, glumatic acid, alanine,cystine, proline and total FAAs even exceeded those during preoverwintering stage respectively.
    LONG-TERM SURVEILLANCE AFTER BASIC ELIMINATION OF BANCROFTIAN FILARIASIS
    1993, 11(1):  21-24. 
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    The longitudinal and cross-sectional systemic surveillance have been conducted for 9-11 consecutive years in six counties (cities) of Guangxi Zhuang Autonomous Region after basic elimination of bancroftian filariasis. The two different control regimens had been used with DEC selective treatment followed by mass treatment of all persons and selective treatment followed by taking DEC medicated salt. During the former 6 years, residual microfilaremia cases could still be detected ; whereas during the latter 5 years, no microfilaremia cases could be detected at all. The natural infection of vector mosquitoes showed negative. The positive rate of antibody in the populations was reduced to 1. 4 -5. 5% detected by IFAT,reaching to the level of local non-endemic areas. The result indicated that the transmission of filariasis in these areas has been blocked. The authors suggested that a period of 10 years might be appropriate for surveillance after basic elimination of bancroftian filariasis.
    ULTRASTRUCTURAL LOCALIZATION OF 185 kDa AND 82/41 kDa PROTECTIVE ANTIGENS IN PLASMODIUM FALCIPARUM, FCC1/HN
    1993, 11(1):  25-28. 
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    Plasmodium falciparum FCCl/HN-infected human erythrocytes were embedded with LR White resin at low temperature. The 185 kDa and 82/41 kDa proteins in erythrocytic stages of P. falciparum were then immuno-labeled by using the protective monoclonal antibodies (McAb)F6-D3 and F6-C2 with protein A-colloidal gold probe. The electron-microscopical observation showed that the 185kDa protein recognized by McAb F6-D3 was located on the surface of free and intracellular merozoites as well as the cytoplasm, plasma membrane, and parasitophorous vaccuole membrane of immature schizonts. The 82/41 kDa proteins identified by McAb F6-C2 was located within the rhoptries of immature schizonts and mature merozoites. These results demonstrated ultrastructurally that the 185 kDa and 82/41 kDa protective antigens were merozoite surface antigen and merozoite rhoptry antigens of P. falciparum FCC1/HN, respectively.
    EARLY ULTRASTRUCTURAL EVOLUTION OF MURINE MALARIA MEROZOITES AFTER ENTERING RED CELLS
    1993, 11(1):  29-32. 
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    A TEM study of murine malaria parasites, Plasmodium berghei and P. yoelii was performed by consecutive sampling in vivo to look into the early sequential changes in the ultra-structure of the merozoites after entering red cells. The results showed that once finishing invasion, the merozoite resided in the peripheral cytoplasm of the red cell, creating a bulge at the invasion site, with an additional unit membrane around it (parasitophorous vacuole); apical structures disappeared; the spherical body was degenerative or atrophic and separated from the mitochondrion and nucleus. The mitochondrion became more extended and the nucleus elongated and curved. There were more Er vesicles in the cytoplasm, taking a dilated polyangular shape. The inner double membrane was separated from the outer membrane and got into incomplete, winding, finally disappeared. Sometimes multimembranous bodies could be seen in the peripheral spaces. Once the dedifferentiation process was over, the merozoite was transformed into an early trophozoite , with a single plasma membrane and decreased density. Individual large Er vesicle with acute angles was found in the cytoplasm, and small food pills appeared beneath the plasma membrane; then the shape of the parasite changed from a ball-like one to a pie-like one, gradually the flat cell body rolled up, with its edges met and fused, resulting in the formation of a large food vacuole,with digestive vac-uoles and pigment granules around it. Thus, it grew into a middle-aged trophozoite.
    EFFICACY OF IVERMECTIN FOR CONTROL OF MICROFILAREMIA RECURRING AFTER TREATMENT WITH DIETHYLCARBAMAZINE: IMMUNOLOGICAL OBSERVATION *
    1993, 11(1):  33-37. 
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    We compared the effect of a single dose of ivermectin (100ug/kg) with that of a standard course of diethylcarbamazine (DEC) (6mg/kg) on several parameters of the host's an-tifilarial 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 amicrofilaremic 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,TNFβ and IFNγ 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.
    ANALYSIS OF PROTEINS AND ANTIGENS IN NINE STRAINS OF TOXOPLASMA GONDII BY MEANS OF SDS-PAGE AND IMMUNOBLOTTING
    1993, 11(1):  38-40. 
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    The proteins and antigens of nine strains of Toxoplasma gondii were analyzed by SDS-PAGE and immunoblotting. These strains including RH strain, Zs-2 strain, CN strain and SHI, SH2, SH3, SH4, SH5, SH8 strains, were obtained from other laboratories or isolated from deformity fetus in our laboratory. SDS-PAGE analysis revealed that these strains were very close in the major bands of proteins and differences were observed only in part. There were common components in antigens of all strains using IgG antibody prepared from high-titre rabbit antisera raised against RH strain of Toxoplasma.
    STUDIES ON THE MECHANISM OF THE PROTECTIVE IMMUNITY AGAINST SCHISTOSOMA JAPONICUM—— CELLULAR IMMUNE RESPONSES
    1993, 11(1):  41-44. 
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    Kinetics of cellular immune responses was studied in C57BL/6 mice immunized with irradiation-attenuated vaccine, cryopreserved and irradiated vaccine or frozen-thawn vaccine. The results and analysis of correlation between cellular resposes and resistance showed that cellular immune responses played an important role in the protective immunity against Schis-tosoma japonicum.
    EFFECT OF GAMMA-IRRADIATION ON INFECTIVITY OF CLONORCHIS SINENSIS METACERCARIAE
    1993, 11(1):  45-49. 
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    The purpose of the present study was to observe the survival and development of Clonorchis sinensis metacercariae in their final hosts after Co-60 gamma irradiation exerting on both metacercariae isolated or in fish. Guinea pigs or albino rats were orally infected by gavage. Bio-assay, fecal examination for ova and dissection of infected animals were used for the estimation of minimum effective dose of gamma irradiation to control infectivity of Clonorchis sinensis metacercariae. Results showed that the minimum effective irradiation dose for isolated metacercariae was 0. 05 kGy. The LD50 of the irradiation dose for metacercariae in fish was 0. 05 kGy, and the minimum effective dose was 0. 15 kGy. No significant difference in radiation susceptibility to Co-60 gamma irradiation was found among Clonorchis sinensis metacercariae in fishes collected at different localities in the northern, middle or southern parts of China. The present finding suggests that irradiation of the fish at a dose of 0. 15 kGy could control the infectivity of Clonorchis sinensis metacercariae and thus be adopted as a control measure in preventive medicine.
    ULTRASTRUCTURAL STUDY ON SPERMATOGENESIS AND SUSTENTACULAR CELL OF THE TESTES OF SCHISTOSOMA JAPONICUM
    1993, 11(1):  50-52. 
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    This paper deals with the ultrastructural study of the spermatogenesis and sustentacular cell of the testes of Schistosoma japonicum by means of TEM. Albeit several papers have reported on the ultrastructural studies of the testes of male reproductive organ of S. mansoni, no systemic observation on the spermatogenesis of schistosome and ultrastructure of the testes of 5. japonicum was available .The authors described the characteristics of the spermatogonium, spermatocyte and different appearance of spermatids. The latter was subdivided into 4 types, namely, Sda, Sdb, Sdc and Sdd, which could be identified by the features of nuclear shape and the density of matrix, the distribution of the mitochondria in the cytoplasm, the appearing and the formation of the acrosome-like structure, the presentation and elimination of the residual bodies, etc. The spermatids were embedded and interdigitated among the sustentacular cells, forming a complicated picture in the field of TEM. The acrosome-like structure and the inclusion of residual bodies were revealed in developing spermatids. The origin and the characteristics of these structures were discussed.
    COMPARATIVE STUDY ON ANTIGENS OF CYSTICERCUS CELLULOSAE BY ELIB AND ELISA
    1993, 11(1):  53-56. 
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    Urea-soluble antigens (Ag-u) and water-soluble antigens (Ag-w) of Cysticercus cellu-losae were studied by using ELIB and ELISA, respectively. The results showed that using Ag-u and Ag-w, 9 and 14 bands of polypeptides could be recognized by sera from cysticerco-sis patients; 4 and 10 bands could be recognized by sera from hydatidosis patients; whereas 4 and 8 bands could be recognized by sera from clornochiasis patients.Using ELISA at serum dilutions of 1 : 400, the positive rate of sera against Ag-u and Ag-w was 96. 6% and 86. 6% .respectively in 60 cysticercosis patients; 16. 6% and 46. 6% respectively in 30 hydatidosis patients and negative in 24 clornorchiasis patients and 50 normal healthy persons, indicating that both Ag-u and Ag-w share common antigen components causing cross reaction with the sera from hydatidosis and clonorchiasis patients. However, such components were fewer in Ag-u than in Ag-w. In view of the fact that Ag-u is superior to Ag-w in both sensitivity and specificity, Ag-u might be better used for the diagnosis of cysticercosis.
    OCCURRENCE OF CVLEX MODESTUS JNATOMII KAMIMURA ET WADA IN RONGCHENG CITY, SHANDONG PROVINCE
    1993, 11(1):  57-59. 
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    A mosquito survey was made at Rongcheng City, Shandong Province in August, 1991. Altogether 4 genera and 8 species of mosquitoes were collected in this survey, namely Aedes dorsalis (Meigen), Anopheles sinensis Wiedemann, An. yatsushiroensis Miyazaki, Culex fus-canus Wiedemann, Cx. modestus inatomii Kamimura et Wada, Cx. pipiens pallens Coquil-lett, Cx. tritaeniorhynchus Giles and Mansonia uniformis (Theobald). Among them Cx. modestus inatomii and An. yatsushiroensis were found to be the first record for China and Shandong Province respectively. The morphology and taxonomic status of the above two species are discussed briefly.
    DETECTION OF CIRCULATING ANTIGEN IN URINE FROM MICE INFECTED WITH TOXOPLASMA TACHYZOITES
    1993, 11(1):  60-62. 
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    Urine samples collected from three groups of mice infected experimentally with different numbers doses of Toxoplasma trophozoites were detected for the presence of Toxoplasma circulating antigen by using fast ELISA.The results showed that presence of circulating antigen in all three infected groups of mice in comparison with the normal control group. Toxoplasma circulating antigen was detected on days 5,4 and 3 after infection in light-,moderate- and heavy- infection groups,respectively. The concentration of circulating antigen was on a parallel with the duration of infection.Western blot analysis of the Toxoplasma circulating antigen in urine revealed the existence of seven specific bands with molecular weights of 75,67,55,43,30,28 and 22 kDa.
    ELIB OF SPECIFIC ANTIGENS IN IN VITRO CULTIVATED GERMINAL CELLS OF ECHINOCOCCUS GRANULOSUS
    1993, 11(1):  63-65. 
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    Specific antigens are detected in cyst fluid and cyst wall of Echinococcus granulosus, as well as germinal cells cultivated in vitro by sodium dodecyl sulphate polyacrylamide gel elec-trophoresis (SDS-PAGE) and enzyme linked immunotransfer blot technique (ELIB), using the sera from mice infected with protoscoleces of E. granulosus for at least 10 months. A specific reaction band of 52 kDa or 38 kDa was detected in soluble protein of germinal cells and cyst fluid, respectively, but these two reaction bands were present concurrently in the cyst wall. The sera from 7 normal controls, 7 hydatidosis patients and 3 cysticercosis patients were used to study the specific antigen from the germinal cells. The results noted that the reaction band of 52 kDa was seen in all the sera from hydatidosis patients, while the sera from normal human controls and cysticercosis patients showed no reaction band.
    PRELIMINARY STUDY ON MONOCLONAL ANTIBODIES AGAINST CYSTICERCUS CELLULOSAE
    1993, 11(1):  66-68. 
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    In order to produce valuable monoclonal antibodies for immunodiagnosis of cysticerco-sis, hybridoma technique was adopted using the fusion of splenic lymphocytes from BALB/c mice immunized with Cysticercus cellulosae antigens and the myeloma cell line NS-1. Through screening and cloning, three monoclonal antibody cell lines have been established. Im- munoglobulin subclasses of 3 lines were determined to be IgGl. These monoclonal antibodies were found to be highly specific and without cross reaction with Echinococcus granulosus hy-datid cyst and Cysticercus fasciolasis. Antigen fractions specifically reacting to monoclonal antibodies were demonstrated with Western blot method. The results showed that specific reaction bands of SCW located in 25 kDa and 17 kDa regions.