Table of Content

31 May 1991, Volume 9 Issue 2

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ADVANCES IN FILARIASIS CONTROL AND RESEARCH IN CHINA DURING 1986-1990

1991, 9(2):  81-85. 

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Based upon the statistical data during 1986-1990 from provincial, regional or municipal institutions involved in the control and research of filariasis, important achievement in filariasis control has been achieved since 1986. During the 5 years, 22 350 772 person were blood-examined, among them, 268 034 were found to be microfilaria positive; a total of 78 550 945 man/times of treatment with DEC were given (including administration of DEC-medicated salt). Till the end of 1990, filariasis has been basically eliminated in 823 counties/cities out of the 864 endemic counties/cities, and has been basically eliminated in 12 endemic provinces, one autonomous region and one municipality. Thus far, filariasis is still prevalent in 41 counties/cities of Anhui province. Parasitological, serological and entomological monitoring on filariaiis is being executed according to the "Technical scheme for filariasis surveillances in areas where the disease has been basically eliminated" formulated by the Ministry of Public Health. The preliminary results of longitudinal surveillance indicated that the decline of microfilaremia rate and the absence of resurgence coincided with the decrease in antibody litre in the population by IFAT. The progress Of research work dealing with the transmission potential in areas where filariasis had been ander control, the methods of immunodiagnosis and the treatment of patients with clinical signs was also reviewed

PRELIMINARY STUDY OF NATURALLY OCCURRING ANTMDIOTYPIC ANTIBODIES IN SCHISTOSOMIASIS JAPONICA

1991, 9(2):  86-89. 

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In this study, naturally occurring anti-idiotypic antibodies in sera from patients with schistosomiasis japonica were demonstrated by using McAb (5B5H)-ELISA. McAb 5B5H against Schistosoma japonicum soluble egg antigen (SEA) was purified by precipitation With 50%, 40% and 33% saturated (NH4)2SO4 and coupled to CNBr-activated Sepharose 4B (Pharmacia). 5B5H column was loaded with sera from two patients with schistosomiasis japonica and then the bound material was eluated with 3M KCNS. The resulting eluate was further characterized with McAb-ELISA and complement fixation test in order to minimize the possible interference of circulating antigen-antibody complex. The results showed that the eluate contained mainly anti-Id antibodies. In the competitive 5B5H-ELISA tests, SEA markedly inhibited the interaction of 5B5H (Id) and anti-Id anti-bodies, suggesting that the relevant idiotype is within or adjacent closely to antigen binding site of anti-SEA molecule. The anti-Id antibodies were detected using 5B5H-ELISA in patients with schistosomiasis japonica from A and B areas, positive rate of 35.1% (13/37) and 60% (18/30) was obtained respectively. No cross or false reactions were found with sera from patients with fasciolopsiasis buski (0/15), clonorchiasis sinensis (0/15) and normal group of students (0/54) with the exception of one out of 20 patients with paragonimiasis westermani.

DETECTION OF PLASMODIVM FALCIPARUM USING THE PLASMID PF REP 2O PROBE (PRELIMINARY REPORT)

1991, 9(2):  90-93. 

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A cloned repetitive DNA sequence (rep 20) labeled with 32P was evaluated as diagnostic probe for P. falciparum in 39 blood samples from Hainan and Yunan provinces. Its specificity and sensitivity were studied and compared with total genomic DNA probe isolated from P. f. Hainan Fccj/HN isolate. The pPF rep 20 probe recognized the DNA of P. f. Hainan, Yunnan and Anhui isolates, but did not hybridize with the DNA of P. vivax, P. cynomolgl, P. knowlesi and P. yoelii. The genomic probe hybridized with the DNA of 3 isolates and cross-hybridized with the DNA of all the other Plasmodium species tested, but did not hybridize with host DNA. The plasmid rep 20 probe was able to detect para-sitemia level of 0.001% in 20μl blood from culture and 10pg DNA of 3 P. f. isolates after 3 days film exposure. It could hybridize with the blood samples of P. f. patients from Hainan and Yunnan with a sensitivity of 95% (37/39). The genomic probe could detect the same parasitemia and DNA levels as plasmid rep 20 probe for Yunnan and Anhui isolates, and 0.0001% parasitemia and 1 pg DNA for Hainan isolate. It had a sensitivity of 97% (38/39) when used to detect patient samples. The results indicated that plasmid rep 20 probe was specific and rather sensitive to DNA of P. falciparum isolates from China and may be useful in epidemiological studies.

ANTI-ANTIBODY RESPONSES OF RABBIT TO MOUSE MONOCLONAL ANTIBODY AGAINST SCHISTOSOME "TARGET ANTIGEN"

1991, 9(2):  94-97. 

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The supernatant of protective McAb (isotype IgG2a) secreted by 1E2 hybridoma line was purified by protein A-sepharose CL-4B column and rabbits were immunized with purified 1E2 McAb. Dot-ELISA, immunodiffusion assay, Western blotting and ELISA were used to observe the presence of anti-McAb and anti-anti-McAb. The main results are: 1. anti-McAb antibody could be detected as early as 20 days post immunization in the immune sera and would be decreased gradually without boosting; otherwise, it would be increased quickly and the liters of anti-McAb were increased within 5 days postboosting and could be maintained at a plateau for 30-50 days, and then decreased gradually to the normal; 2. there were different anti-anti-McAbs in the immune sera. Anti-anti-McAb, like anti-anti-idiotype antibody, can recognize different schistosome antigens and 90, 68 or 45 kDa antige.nic determinants. The level of anti-anti-McAbs varied from tilers 1:100 to 1:1 600 at different time post-immunization with 1E2. The results provide evidence to understand the appearance of anti-McAb antibody and the way to develop anti-idiotype and anti-anti-idiotype McAb for research purpose.

CONSTRUCTION OF ECHINOCOCCUS GRANULOSUS GENOMIC LIBRARY

1991, 9(2):  98-101. 

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Using EMBL3 phage DNA as a vector, a perfect genomic library of Echinococcus granulosus from sheep from Xinjiang has been constructed, which contains 1.2×06 independent recombinants.The main procedure of construction comprised: 1. extraction of Echinococcus granulosus genomic DNA, 2. partial digestion of the extracted E. granulosus genomic DNA with restriction enzyme Sau3A1, 3. harvest of 15-23 kb DNA fragments by electric elution equipment, 4. preparation of EMBL3 phage vector DNA, 5. cleavage of EMBL3 vector DNA with two restriction enzymes Bam HI and Eco RI to remove the central fragment, 6. ligation of the harvested 15-23 kb E. granulosus genomic DNA and the cleavaged vector DNA with T4 DNA ligase, 7. the package reaction of ligated recombinant DNA in vitro with the package protein and with Q359 strain (Spi-) to screen recombinants, 8. identification of the genomic library, 9. hybridization in situ by pSM889 probe, obtaining 6 positive recombinant clones. (Figs. 1-6)It was estimated that the E. granulosus genome was about 1.5×108 bp. A perfect E.g. genomic library is expected to contain 4.6×104 independent recombinants at minimum The construced genomic library has enough independent recombinants (1.2×106).This is the first time to establish an E. granulosus genomic library in China. Previous work showed that there existed differences in many aspects, including pathogenicity, among various isolates of E. granulosus from different hosts and areas. We plan to employ this library to screen the E. granulosus intraspecies DNA probe by hybridization in situ. This kind of probe is envisaged to be of advantage for epidemiological investigation of the hydatid disease in China. It also provides a base for researching E. granulosus at the molecular level.

ACTIVATION OF THE LATENT TOXOPLASMA INFECTION AND CYST FORMATION IN MICE

1991, 9(2):  102-105. 

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Latent Toxoplasma infection in mice inoculated with the low virulent Beverley strain (BEV) and avirulent Fukaya strain (FUK) was reactivated by prednisolone administration: Parasitaemia reappeared and the organism could be continuously isolated from the lymph nodes by mouse passage. No distinct decrease in specific antibody levels was observed when the sera were assayed by dye test and latex agglutination test. A significant increase in the number of brain cysts in infected mice was noted at the third week of infection while the challenge infection and steroid immunosuppression treatment resulted in an enha-ncement of cyst formation. A hypothesis was, therefore, proposed that the cyst fromation in tissues might be regulated by the immune response of infected host to Toxoplasma infection.

OBSERVATIONS ON THE DEVELOPMENT OF QUANTITATIVELY INOCULATED BRUGIA MALAY I MICROFILARIAE IN ANOPHELES SINENSIS AND CVLEX QUINQUEFASCIATUS

1991, 9(2):  106-109. 

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With an improved technique, quantitative inoculation of Brugia malayl microfilariae (mff) into Anopheles sinensis and Culex quinquefasciatus was carried out in our laboratory in 1988. The development of B. malayi mff in these two species of mosquitoes was observed. In the system of B. malayi and An; sinensis, a well-fitted linear correlation appeared between the number of mff inoculated and the infective larva (L3) positive rate (r= 0.9910; P0.01). The regression equation with the regression coefficient of 8.490 sugj gested a high susceptibility of this species of mosquito to B. malayi even under the condition of experimental inoculation. The quantitative relationship between the number of mff inoculated and the average filarial maturity rate was also exhibited. At the same dosages of 4 and 10 mff/mosquito, the L3 positive rates and the average filarial maturity rates in An. sinensis were much higher than those in Cx. quinquefasciatus (P0.01), indicating significant difference occurred inside the bodies of these two species of mosquitoes.

ANTIGENIC DIVERSITY OF ASEXUAL SCHIZONT ANTIGEN GP195 OF PLASMODIUM FALCIPARUM ISOLATES FROM CHINA

1991, 9(2):  110-113. 

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The antigenic diversity of asexual merozoite surface antigen precursor gp195 among 6 isolates of Plasmodium falciparum from Hainan and Jiangsu provinces of China was investigated with a panel of murine anti-gp195 McAbs by indirect immunofluorescence assay and Western blotting. The results show that all isolates express certain strain-common epitopes of gp195, and at the same time express or lack some strain-specific epitopes. The 6 isolates can be divided into two major gp195 serotypes according to the reactivity patterns with the panel of anti-gp195 McAbs. Remarkable molecular weight difference in gp195 was found among 4 isolates of P. falciparum in which the Jiangsu isolate possesses a large size of gp195 (210kD.) than the other 3 Hainan isolates (≤200kDa). The polymorphism of gpl95 and it's impact on the development of antimalarial vaccine is discussed.

ELECTRON MICROSCOPIC CYTOCHEMISTRY STUDIES ON MEMBRANE-BOUND ORGANELLES OF TRICHOMONAS HOMINIS

1991, 9(2):  114-117. 

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This paper presents the results of an electron microscopic cytochemistry study on the menbrane-bound organelles of Trichomonas hominis. Acid phosphatase (ACP) and cyti-dine monophosphatase (CMPase) were located in the primary lysosomes, digestive vacuales, as well as in the parabasal body stacks, being usually in its mature surface sacs. Thiamine pyrophosphatase (TPPase) and nicotinamide adenine dinucleotide phosphatase (NADPase) were found in the saccules, being on the mature surface and in the intermediate saccules of parabasal body stacks, respectively. The reactive products of peroxidase (POase) were seen only in the digestive vacuoles. Cytochrome oxidase (COase) and catalase (Cat) reactions were both negative. It is suggested that T. hominis lacks mitochondrion and microbody but possesses hydrogenosome. The parabasal body, endoplasmic reticulum and hydrogeno-some were stained well with the U-Pb-Cu impregnation technique. (Figsl-11)

LOCALIZATION OF ANTIGEN AND ANTIBODIES IN THE LIVER AND INTESTINE OF MICE WITH SCHISTOSOMA JAPONICUM

1991, 9(2):  118-121. 

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Indirect fluorescent antibody test was used to localize the antigen in the livers and intestines of mice with Schistosoma japonicum. No antigen was detected 4 weeks p. i.. There was a significant rise in antigen level 6 weeks p. i. which reached peak level 10-12 weeks p. i., the GMRT being 512 and 483, respsectively. The eggs in the tissues showed strong fluorescent reaction 6 weeks p. i.. The mean diameter of schistosome egg granulomas in the livers and intestines of infected mice was remarkably enlarged 6 weeks after infection. The mean diameter of egg granulomas in the livers was markedly larger than that in the intestines. The antibodies were localized in the livers and intestines of infected mice as show en by the direct fluorescent antibody test (DFAT) and IF AT. The results indicated that the levels of IgG, IgM and IgA antibodies appeared 6 weeks p. i. which went on a significant increase at the 10-12weeks. The IgG antibody level was higher than that of other two antibodies. It is suggested that the IgG may be the main antibody in the immunologic response of Sj egg granulomas.

DETERMINATION OF CIRCULATING ANTIGEN IN CYSTICERCOSIS PATIENTS USING MCAB-BASED ELISA

1991, 9(2):  122-125. 

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For the first time, the determination of circulating antigen in patients with cysticetocsis using specific monoclonal antibody against cysticercus antigen (CCy1) based on inhibitive ELISA was reported. The circulating antigens were detected in the sera from 83 patients with cysticercosis, the positive rate being 71.1%. The range of the detectable serum antigen concentrations was 0.16-128μg/ml. In 41 cases of cysticercosis patients, circulating antigens were determined in both sera and cerebrospinal fluids, the positive rates being 68.3% and 78% respectively, the total positive rate being 90.2%. (Fig.l) In 114 sera from normal persons, circulating antigen was absent. In 30 sera from patients with hydatidosis, 30 with clonor-chiasis, 20 with schistosomiasis japonica, 24 with paragonimiasis, and 5 sera collected from non-parasitosis patients, serum circulating antigen was not detectable. In another 10 non parasitosis patients, circulating antigen was not found in cerebrospinal fluid. After chemotherapy for one half to one year, in 21 out of 23 cases of cysticercosis patients, the circulating antigen levels in sera dropped to zero, except for two cases having an antigen evel of 0.64μg/ml and 1.6μg/ml, respectively. Our results showed that the determination of the circulating cysticercus antigen was very specific for the diagnosis of active infection of cysticercosis and could be used as a rational tool in monitoring the effectiveness of chemotherapy.

OBSERVATION ON THE PRODUCTION OF INTERLEUKIN-1 AND INTERLEUKIN-2 AND RESPONSE TO INTERLEUKIN-2 IN PATIENTS WITH SCHISTOSOMIASIS

1991, 9(2):  126-129. 

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The ability of adherent and nonadherent peripheral blood mononuclear cells (PBMC) from forty patients with schistosomiasis to produce IL-1 and IL-2 was studied. The results indicated that ConA-stimulated nonadherent-PBMC from patients exhibited a decreasing ability to produce IL-2 compared with controls (P0.001), and that their ConA-activated blast cells expressed a smaller number of cell surface IL-2 receptor since IL-2 adsorption to the patient cells was lower than that to the normal cells (P0.01). On the other hand, IL-1 production by LpS-stimulated adherent-PBMC from the patients was in agreement with that from the normal controls (P0.05). From above results, it seems that human organism following infection of Schistosoma japonicum might display a sort of supressive phenomenon n the production of and the response to IL-2.

FREEZE-ETCH STUDY ON THE BRUSH BORDER STRUCTURE OF CYSTICERCVS CELLVLOSAE

1991, 9(2):  130-133. 

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The images of C. cellulosae detected by freeze-itch technique were exactly similar to those observed in the thin section.The scolex microtriches might be divided into two parts, a thick proximal portion and a thinner spinal distal end, the former measuring about 0.2-0.4μm in length, the latter measuring about 1-2μm in length. On the extracellular surface of the proximal portion of microthrix, 1 or 2 particles could occasionally be seen, while numerous particles appeared on the protoplasmic fracture face (PF face) of the proximal portion. The PF face were closely packed and irregularly distributed with membranous particles, which were spherical or subspherical in shape, measured 0.01-0.02μm in diameter. The extracellular fracture face (EF face) of proximal portion and all four membranous faces of spinal end were smooth.The tegumentary plasmic membrane was 0.02μm in thickness, with smooth ES face. The PF face of this membrane packed closely with numerous particles, which were similar with those on the PF face of the microthrix. Numerous globular or discoidal vesicles scattered at random in the tegumentary matrix. Most mitochondria were near the basement membrane of the matrix.In the paranchymal layer, the paranchymal cells, calcareous corpuscles and flame-cells: could easily be seen. Most of the calcareous corpuscles and flame-cells were located closely beneath the muscle layer. The flame-cell of C. cellulosae mainly consisted of three portions,. cell body, a bundle of cilia and a filtered cell lumen. The flame-cell body had a large nucleus and relatively few cytoplasm with several mitochondria. The cilia of flame-cell formed a bunch of cilium tuft bundled up closely by protoplasmic membrane. The diameter of tuft meausred about 2.2-3.0μm. These cilia were arranged regularly in several lines, each line contained 1011- cilia. The total number of the cilia in a flame-cell tuft was 70-90. The cilia appeared as regularly hexagonal near the flame-cell body and cylindrical at the distal end. The cilium was 0.2-0.25μn in diameter and covered by cytoplasmic membrane. On the PF face of the membrane of cilium numerous particles occurred, amounting to 2-10 in number per 0.1 cubimicron area. There was a cone-shaped flame-cell lumen surrounding the central tuft of the cilia. The lumen wall varied greatly. At the head part of lumen, proximal to the flame-cell body, the wall had 1 or 2 rows of stiffening cilia. These cilia were slender than those of the central tuft, arranging in a bar-like structure around the tuft. A leptoslit could usually be found between the cilia. (Figs1-16).

OBSERVATION ON THE BEHAVIOR OF MICROFILARIAE IN HUMAN FILARIASIS

1991, 9(2):  134-136. 

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A total of 19 female adult filarite containing microfilarke in uteri collected from 25 filariasis patients were examined. Light transmission microscopic observations showed: (1) some of the adult worms entered the lumen of blood vessels by penetrating the venous wall and discharged immature and mature microfilariae and embryos into the blood stream; (2) microfilariae developed into maturation in the uterus of adult female worms, but when the adult worm began to degenerate, the microfilariae did not degenerate concurrently; (3) some microfilariae could form thrombus, inducing the infiltration of segmented neutrophils and eosinophils followed by the formation of granuloma; (4) embryos 8 female adults parasitizing lymphatics were seen to discharge immature microfilariae and ova, which might form emboli after entering the blood stream.

PROTOSCOLICIDAL EFFECT OF SOME CHEMICAL AGENTS AND DRUGS AGAINST ECHINOCOCCUS GRANVLOSVS

1991, 9(2):  137-139. 

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The present paper reports the protoscolicidal action of hydrastine, ether-acetic acid-1 ethanol admixture, H2O2, pyquiton and albendazole through in vitro or in vivo exposue, for 15 minutes and transplantation studies. The mortality of protoscblices in vitro and in vivo were 70.2% and 68.9% for 0.3% hydrastine, 56.8% and 56.2% for 10% ether-acetic acid-ethanol admixture, 6.0% and 8.8% for0.3% H2O2; 6.1% for 0.004% pyquiton in vitro and 5.0% were 10% and 25% for 0.3% hydrastine, 30% and for 0.004% albendazole in vitro. The survival rates after transplantation of protoscolices 37.5% for 10% ether-acetic acid-ethanol admixture, 100% and 95% for 0.3% H2O2 respectively. Disruption of external plasma membrane, hook detachment, sucker deformitv of protoscolices exposed to hydrastine were demonstrated by scanning electron microscopy. It is suggested that hydrastine exerts a profound intracellular effect on the protoscolex of E. granulosus of sheep and man, and might be a promising protoscolicide as adjuvant to hydatid surgery.

EIGHTY CASES OF ALVEOLAR HYDATID DISEASE TREATED WITH ALBEISDAZOLE

1991, 9(2):  140-142. 

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Alveolar hydatid disease occurs frequently in Xiji County of Ningxia. 80 cases of the disease were treated orally with albendazole from 1985 to 1988 and the short-term results proved satisfactory.The treatment consisted of two groups. Group Ⅰ included 72 cases which were orally given 8-10 mg/kg · d of albendazole 2 to 3 times a day after each meal for 30 days and then stop taking the medicine for 10 days as one trealment course. The treatment continued 3-12 months comprising about 24 courses were given with the highest dosage of 412g. Group Ⅱ included 8 cases who were given 15.6-20mg/kg · d of the medicine for 14 days (one course) and every two weeks with a 10 days interval. The treatment of group Ⅱ continued 3-6 months which totalled 19-24 courses with the highest dosage of 270g. All the treated patients tolerate well except that a few of them felt giddy and had diarrhoea which disappeared after the withdrawal of medicine.Through 3-5 years, follow-up observation, it was found that the gener alsymptoms of the treated partients improved and their body weight increased by 2-9.5kg., some of them could take part in light physical labour. The jaundice index in 80% of them returned to normal. SGPT in 86.4% decreased to within normal range. The enlarged livers in half of the patients decreased by 1-6cm. 23.7% of the patients were reexamined by B ultrasound scanning which revealed that their enlarged liver reduced in size while the liquifaction area and the shadows of calcification in the livers in 42.5% patients increased obviously.

PRELIMINARY INVESTIGATION OF LIVER ALVEOLAR ECHINOCOCCOSIS AND LIVER CYSTIC, ECHINOCOCCOSIS IN XIJI COUNTY, NINGXIA

1991, 9(2):  143-145. 

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This article reports on the result of an investigation on the prevalence of liver alveolar echinococcosis (LAE) and liver cystic echinococcosis (LCE) in the peasants and the residents of Xiji County, Ningxia Hui Autonomous Region. Among 2 389 selected persons examined with B-ultrasound, 197 cases were diagnosed to have LAE or LCE; the prevalence being 8.2% . Of the 197 cases, 141(5.9%) had LAE; 56(2.3%) had LCE. Among 1 413 peasants, 9.7% had LAE; 3.8% had LCE. Among 976 residents, 0.4% had LAE, 0.2% had LCE. Obviously, the peasants were more prone to be infected with the disease, suggesting LAE had much to do with the job of hunting the fox and capturing the Citellus dauricus, while the infectious source of LCE was mainly the domestic dog.