Table of Content

31 August 1993, Volume 11 Issue 3

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EFFICACY OF PYQUITON IN THE TREATMENT OF ECHINOCHASMUS LILIPUTANVS INFECTION

1993, 11(3):  165-167. 

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Two hundred cases of Echinochasmus liliputanus infection were randomly divided into three groups and treated with pyquiton at a single dose of 10,5 and 2. 5 mg/kg, respectively. As assessed one month after treatment the egg negativity rates were 100%, 98. 7% and 96,5%, respectively. The symptoms such as abdominal pain, distension, diarrhea and anorexia relieved. The results suggest that pyquiton is effective against Echinochasmus liliputanus infection.

STUDIES ON THE HISTOCHEMISTRY OF CULEX TRITAENIORHYNCHVS LARVAE INFECTED WITH COELOMOMYCES INDICA

1993, 11(3):  168-171. 

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A sectional survey with histochemical technique was carried out on Culex tritae-niorhynchus larvae infected with Coelomomyces indica in comparison to the noninfected larvae. Studies were pursued by using micrograph and imaging analysis. The results showed that the glycogen, protein and nucleic acid (RNA and DNA)reaction in the infected group were less than those of the control group. The gray level assessment in tissue imaging showed marked difference between the two groups. It is suggested that C. indica has significant effect on the above biochemical elements of the mosquito larvae, which might be considered an important mechanism in the pathogenicity of the fungus.

ANALYSIS OF PATHOGENICITY OF ENTAMOEBA HISTOLYTICA BY POLYMERASE CHAIN REACTION

1993, 11(3):  172-175. 

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DNA from five isolates of Entamoeba histolytica were examined for their pathogenicity by polymerase chain reaction. Three isolates SH-3,SH-6,SH-8 were isolated from patients with acute amoebic dysentery, whereas SH-5 and SH-7 were isolated from asymptomatic cyst passers. Gel electrophoresis of PCR products showed that primers P11 , P12 for pathogenic strains could amplify genomic DNA extracted from SH-8 , and primers P13, P14 for non-pathogenic strains could amplify genomic DNA extracted from SH-3, SH-5, SH-6 and SH-7. Furthermore, zymodeme analysis and the reactivity of McAb 4G6, which recognizes the 30 kDa antigen of pathogenic E. histolytica indicated that only SH-8 was pathogenic, while the others were nonpathogenic. The results of the genotypic analysis by PCR were in accord with the phenotypic properties.It is suggested that there are differences in genomic DNA between pathogenic and non-pathogenic strains. PCR is a highly sensitive and specific method for genomic DNA analysis of E. histolytica.

ESTABLISHMENT OF TWO CELL LINES SECRETING MONOCLONAL ANTIBODIES AGAINST PATHOGENIC FREE-LIVING AMOEBA IN SHANGHAI

1993, 11(3):  176-179. 

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Taking Naegleria australiensis, a species of pathogenic free-living amoeba (isolated in Shanghai in 1986), as antigen, two cell lines which provided potentially permanent source of monoclonal antibodies were established by lymphocytic hybridoma technique. The results of identification showed that: (1) the two cell lines could secret two different kinds of McAbs; (2) both of the McAbs were IgG (by gel diffusion); (3) McAbs produced in BALB/c mice were at high concentrations. One of them had a titer of ≥1 : 8 192 and the other≥l : 1 024 (by enzyme linked immunosorbent assay). A decline of the titers after purification by salting-out method was shown. One of the purified McAbs had a titer of≥1: 2 024 and the other≥l : 128.We have adopted two ways of recovering cryopreserved cells : ordinary recovering and "direct" recovering. The latter way was more practical because it could reduce the cycle of antibody production, and avoid contamination and chromosome variation. Experiments with different doses of cells revealed that, if the latter way was used, the optimal dose was 3 to 5 × 106 cells per mouse.

STUDIES ON THE ESTABLISHMENT OF MALARIAL ANIMAL MODEL OF SHORT-TERM REPLAPSE Ⅲ. COMBINED THERAPY WITH PYRONARIDINE-ARTEMETHER-CHLOROQUINE FOR PARASITEMIA CLEARANCE

1993, 11(3):  180-184. 

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To establish a Plasmodium cynomolgi-monkey model of short-term relapse, different an-timalarials have been used to inhibit recrudescence so as to elude the confusion between the two different onsets. When a single dose of effective schizonticides pyronaridine, artemether or chloroquine was administered, recrudesence readily occurred.This paper reports the results of the combined therapy with the above three drugs. Seven rhesus monkeys from Guangxi Autonomous Region infected with Plasmodium cynomolgi from Vietnam by blood transmission were rapidly cured by combined therapy with pyronaridine 6 mg/kg-artemether 100 mg/kg-chloroquine 10 mg/kg (PAC-1) once daily for 3 days. The average time of parasite clearance was 3.. 43 ± 0. 89 d and the curvilinear regression equation of parasite density after treatment was Y = 103.94-0.83X. Severe side effects of the gastrointestinal tract occurred during the course of treatment, though no recrudescence was found after 300 - 400 days. To reduce the side effects, another test was carried out in 3 monkeys and the dosage regimen was modified to pyronaridine 6 mg/kg-artemether 10 mg/kg- chloroquine 20 mg/kg (PAC-2) once daily for 3 days. There was no obvious side effect in the tested monkeys and the parasites were cleared during a mean time of 2. 67 ±0. 58 d and the curvilinear regression equation of parasite density was Y=103.7-1.46X, No recrudescence was detected in the animals during a follow-up of 180 days.The study shows that PAC-2 regimen of the combined therapy is effective for para-sitemia clearance and might be adopted for establishment of the monkey model of short-term relapse.

COMPARISON OF THE TRANSMISSION DYNAMICS AND THE CONTROL EFFECTS BETWEEN MALARIA AND FILARIASIS BY USING MATHEMATICAL MODEL

1993, 11(3):  185-189. 

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By dynamic modeling based on Ross MacDonald's mathematical model, the characteristics of rapid transmission of malaria and slow transmission of filariasis was compared. The dynamic mechanism showed that the infection efficiency in filariasis, namely, the probability of becoming infected in man by one infective bite of mosquito, was much lower than that in malaria; hence the vectorial capacity or transmission velocity in filariasis was also markedly lower than that in malaria. Since the intensity of infection i. e. the microfilaria density can largely affect the infection efficiency in filariasis, drug treatment, especially using DEC -medicated salt can reduce the intensity of infection and the infection efficiency, thus interrupting transmission finally. However, for malaria, only when the measures for mosquito vector control (including mosquito proofing) are taken as a priority to reduce the vectorial capacity or transmission velocity, malaria can then be controlled subsequently. These theoretical analyses are being demonstrated by the practice for malaria and filariasis control in our country, which could also be used as a theoretical base for enlightening the successful filariasis control strategies in our country.

STUDIES ON RESIDUAL ANTIMALARIAL ACTIVITY OF TRIPYNADINE IN MICE AND MONKEYS"

1993, 11(3):  190-194. 

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This paper reports the experiments in which tripynadine free base at a dose 4. 5 times that of ED50 was given to mice by intragastric administration. On the 20th day following the administration the mice were inoculated with 1 × 107 RBC infected with Plasmodium berghei ANKA strain. The infection rate was zero, implying that all mice had acquired protection. Although the residual activity time of tripynadine phosphate was longer than that of tripynadine free base or piperaquine phosphate, but tripynadine phosphate caused vomiting in monkeys during the medication. The residual antimalarial activity of tripynadine hydroxynaph-thoate was less than that of tripynadine phosphate or tripynadine free base. A total dose .of 200 mg/kg of tripynadine free base ensured residual antimalarial activity against P. cynomolgi bastianellii for 20 days. However, the residual activity decreased evidently when the total dose was reduced to 100 mg/kg. In short, it seems that the residual antimalarial activity of tripynadine free base is slightly less than that of piperaquine in monkeys.

A STUDY ON THE MONOCLONAL ANTI-IDIOTYPIC ANTIBODY NP30 FOR THE DIAGNOSIS OF SCHISTOSOMIASIS JAPONICA

1993, 11(3):  195-197. 

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In this study the ability of the monoclonal anti-idiotypic antibody NP30 was tested as a substitute of diagnostic antigen in detecting antibody of Schistosoma japonicum from human sera by use of ELISA. The results showed that the seropositive rate was 98% with NP30 in the group of acute infection, which was comparable to 94% with gut associated antigens (GAA)and 98% with the soluble egg antigens (SEA); 87% with NP30 in the group of chronic infection which was comparable to 86% with GAA but lower than that of 98% with SEA. The false positive rate was about 3% for all three diagnostic antigens. The results also showed that the geometric mean titer (GMT) of antibody to NP30 was higher than that to GAA but lower than that to SEA in the acute infection group and the GMT of antibody to NP30 was lower than both those to GAA and to SEA in the chronic infection group,suggesting that the antibody to NP30 appeared earlier and decayed more quickly during the process of infection. The authors suggested that NP30 could be used for the diagnosis of schistosomiasis japonica.

CHARACTERIZATION OF ECHINOCOCCUS GRANULOSUS AND ECHINOCOCCUS MULTILOCULARIS BY DNA PROBE

1993, 11(3):  198-200. 

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Cloned DNA fragments pHD5,pSM889 and pEG18 have been used as DNA probes in the restriction endonuclease analysis and southern blot hybridization to characterize E. granulo-sus and E. multilocularis protoscolices from China. Southern blot hybridization method is sensitive, specific and has the advantage in identification over microscopic examination. The authors deem that it can be used in the base-line epidemiological survey and surveillance of hy-datid disease to provide data for hydatid disease control.

RFLP ANALYSIS OF DNA FROM ECHINOCOCCUS GRANULOSUS COLLECTED FROM FOUR PROVINCES/AUTONOMOUS REGION IN CHINA

1993, 11(3):  201-203. 

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A fragment of the ribosomal RNA gene of Schistosoma mansoni pSM889 and two DNA fragments specific to Echinococcus granulosus pHD5 and pEGlS have been used as DNA probes to assess the extent of genetic variability within E. granulosus. The DNA analysis,including restriction endonuclease digestion and Southern blot hybridization with the probes , did not demonstrate any genetic variation among E. granulosus collected from sheep in Xinjiang, Qinghai,Gansu and Ninxia. Similarly,there was no genetic variation among E. granulosus isolates collected from yak in Qinghai and Gansu provinces. The authors deemed that the yak isolates and the sheep isolates of E. granulosus appear to belong to a same strain.

PURIFICATION AND PHYSICOCHEMICAL CHARACTERIZATION OF ALLERGEN I from Dermatophagoides farinae

1993, 11(3):  204-206. 

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Dermatophagoid.es farinae allergen Ⅰ (Der f Ⅰ ) has been extracted and purified from spent culture medium of Dermatophagoid.es farinae by affinity chromatography coupled with anti-Der f Ⅰ McAb for the first time in China. Furthermore,its physicochemical properties were analysed. By SDS-PAGE,.Der f Ⅰ was estimated to have a molecular weight of 24 kDa and appeared as only one protein band. By isoelectric focusing ,it was revealed to have pIs of 4. 8 - 7. 5 with six protein bands,suggesting that Der f Ⅰ is heterogeneous with complicated composition.

EPIDEMIOLOGICAL STUDIES ON HUMAN CRYPTOSPORIDIOSIS IN RURAL AND URBAN AREAS OF JIANGSU

1993, 11(3):  207-210. 

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A survey of cryptosporidiosis in outpatients and inhabitants in Xuzhou city and 6 rural areas of Jiangsu Province was carried out from 1989 to 1991.Cryptosporidium oocysts(CSO) were found in 97((1. 6%)of 6 221 individuals as a whole, and were detected in 39 (3. 3%) of 1 172 outpatients among the examinees. 39 cases were from 31 towns and villages of 8 counties near Xuzhou city. Among the 136 cases,83 were males and 53 females,of them 89 (65. 4%)were infants and young children. The incidence was evidently higher in the group of children under 4 than in that aged 4 to 15(P0. 01). Diarrhea,intermittent or persistent,was the main symptom of cryptosporidiosis,being present in 94(69. l%)of the 136 positive cases, while the other 42 were asymptomatic carriers. The results of routine blood examination and immunoassay performed in a part of the infected children indicated that more than half of them had anemia and lessened cellular immunity. Stool examination of the domestic animals of the affected households showed that a pig and a dog were CSO positive.

AN INVESTIGATION ON THE FRESHWATER CRAB AS THE HOST OF PARAGONIMUS IN HUNAN PROVINCE

1993, 11(3):  211-212. 

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Through an investigation of the freshwater crabs in 39 counties of Hunan province, 20 species of fresh water crabs were found as the intermediate hosts of Paragonimus. They belong to three genus and two families, in which 10 are new species (including 4 new subspecies). Besides,the natural infection with lung fluke metacercariae was also observed in some of the fresh water crabs.

SCANNING ELECTRON MICROSCOPIC OBSERVATIONS ON THE COPULATORY SPICULES OF THE MALE NECATOR AMERICANUS AND ANCYLOSTOMA DVODENALE

1993, 11(3):  213-214. 

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Scanning electron microscopic observations were made on the morphological structures of the two copulatory spicules of the male Necator americanus and Ancylostoma duodenale. In both species,one of the two copulatory spicules was in the shape of a concave groove and the other, in the shape of an oblate tube. Owing to the difference in the concavity of the groove shaped copulatory spicule between the two species as shown by the cross sections, Necator americanus usually appear to have only one copulatory spicule whereas Ancylostoma duodenale usually show two separate copulatory spicules in appearance (Figs 1 -10).

CLINICAL ANALYSIS OF 1314 CASES WITH HEPATIC HYDATIDOSIS

1993, 11(3):  215-218. 

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One thousand three hundred and fourteen cases of hepatic hydatidosis confirmed by surgical operation were analysed. Most of them contracted this disease in childhood,and hydatid cysts developed slowly without eliciting distinct symptoms until the occurrence of complications. The chief complaint was abdominal mass with pain in the right hypochondrium. The main complications in 1 314 patients were shown to be secondary bacterial infection of hydatid cysts (20. 2%),cyst rupture(9. 9%),portal hypertension (2. 4%)and anaphylactic reaction (1. 9%). By employing the advanced diagnostic technique especially the combined use of ultrasonography,roentgenography,CT scanning and seroimmunological diagnosis,the percentage of preoperative diagnosis might be raised to as high as 100%.

FIELD STUDIES ON DIFFERENT CONTROL SCHEMES FOR HOOKWORM INFECTION

1993, 11(3):  219-223. 

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Three different control schemes including selective chemotherapy, a combination of selective chemotherapy and management of fecal disposal and mass treatment with mebenda-zole-medicated salt were implemented for the control of hookworm infection in Luwo Town and Taiping Village, Wuming County, Guangxi Zhuang Autonomous Region during 1971 -1990. Through ten years of selective chemotherapy, the results showed that the hookworm infection rate dropped from 42. 6% to 3. 9% and the infection intensity from 425. 6 eggs per gram faeces to 1. 6 eggs per gram faeces. After seven years of selective chemotherapy combined with management of fecal, the hookworm infection rate dropped from 58.7% to 10. 9% and the infection intensity from 111. 5 eggs per gram faeces to 8. 5 eggs per gram faeces. However, 3 years after the termination of the combined treatment,the hookworm infection rate increased to 14. 5%. As for the implementation of the third scheme, mebendazole- medicated salt was given at 100 mg daily for 30 consecutive days or at 50 mg daily for 30 consecutive days. Stool examination was made one year after the treatment,the results showed that the infection rate of the inhabitants dropped from 36% and 36% to 2% and 1. 3%, respectively, and the infection intensity dropped from 110. 3 and 246 eggs per gram faeces to 1. 3 and 0. 24 eggs per gram faeces. After three years, the infection rate of inhabitants'remained under 2% and the infection intensity under 1 egg per gram faeces. It was concluded that mass treatment with mebendazole-medicated salt might be the most practical scheme for the control of hookworm infection.