Table of Content

31 August 1992, Volume 10 Issue 3

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ISOLATION AND PURIFICATION OF PNEUMOCYSTIS CARINII CYST

1992, 10(3):  166-170. 

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Twenty Wistar rats were injected with cortisone acetate twice a week subcutaneously for 6-12 wks.By 7 weeks Pneumocystis carinii pneumonia was induced in rats successfully.The cysts of Pneumocystis carinii from infected lungs of cortisonized rats were indentified by phase-contrast microscopy,Giemsa's stain,Chalvardjian's stain and Gomori's methenamine silver nitrate stain.The process of isolation and purification of Pneumocystis carinii from infected rat lungs included the following three test steps.First,the tissue was cut into small pieces and homogenized and filtered through #60,#100,#200-gauge wire mesh respectively.Secondly,the homogenate was digested with collagenase,the optimal concentration of collag-enase being 0.2%.Thirdly,the discontinuous percoll density gradient centrifugation was used to separate P.carinii cysts.The majority of P carinii cysts were present in a density zone of approximately 1.033g/ml and were essentially free from host lung debris,the latter being removed due to their higher density,1.040g/ml.

DIAGNOSIS OF TOXOPLASMOSIS BY POLYMERASE CHAIN REACTION

1992, 10(3):  171-175. 

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Based on the partial sequences of the specific DNA cloned fragment from T.gondii (ZS2 strain) a specific primer of the oligonudeotide for the Toxoplasma gondii DNA sequence has been designed and synthesized in our laboratory.The method of the DNA diagnosis for to-xoplasmosis by polymerase chain reaction (PCR) has been established.A specific amplified band was shown in the PCR products from DNAs of T.gondii and seven manifold terata.The DNAs from the peripheral blood leukocytes of fifty normal individuals and seventy-five patients as infants with hepatitis syndrome and pregnant women with previous abnormal birth histories were diagnosed by PCR.Among the seventy-five diagnosed cases,ten were positive.The normal individuals all were negative.Using 32P-cloned T.gondii specific DNA fragment as probe and Southern blot assay,the results showed that the probe only hybridized to the speciific amplified DNA bands,but did not hybridize to the amplified DNA products of negative cases.Our PCR method is a rapid,highly specific and sensitive one for delecting toxoplasmosis as compared with DNA probing,immunoassay and animal inoculation.

STUDIES ON THE ESTABLISHMANT OF MALARIAL ANIMAL MODEL OF SHORT-TERM RELAPSE I. ASYNCHRONOUS GROWTH OF EXOERYTHSOCYTIC SCHIZONTS OF PLASMODIUM CYNOMOLGI

1992, 10(3):  176-178. 

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A monkey was infected with sporozoites of Plasmodium cynomolgi from Vietnam.Parasite emia was detected on the 8th day with a starting density of 17/100 white blood cells.22 hours after that time,many EE schizonts appeared with an average density of 3.74±0.66 per mm3 hepatic tissue in liver biopsy specimens from the monkey.Most of the EE schizonts were immature and grew at an uneven rate,having an average diameter of 34.22±7.28μm but some of them even remained 15.75±2.47μm in diameter similar to the EE.schizonts on the 6th day.The results showed that the EE schizonts of Plasmodium cynomolgi were asynchronous in growth.The authors suggest that the release of merozoites from liver might be a successive process for many times,and not to be completed at a time.

EFFICACY OF IVERMECTIN FOR CONTROL OF MICROFILAREMIA RECURRING AFTER TREATMENT WITH DIETHYLCARBAMAZINE I.CLINICAL AND PARASITOLOGICAL OBSERVATIONS

1992, 10(3):  179-183. 

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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 banrroftian filariasis who had developed recurrent microfiiaremia 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.

CHARACTERIZATION OF A SURFACE ANTIGEN OF PLASMODIUM FALCIPARUM MEROZOITE WITH MONOCLONAL ANTIBODY

1992, 10(3):  184-186. 

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The monoclonal antibody (McAb) designated as C6 against erythrocytic stage of Plas-modium falciparum Fcc7801/HN showed significant growth inhibition of P.falciparum in vitro,having cross immunofluorescence reaction with P.falciparum Fcc-1/HN,Fcc7802/HN,Fcc8703/JS and P.berghei,P.cynomolgi.McAb C6 bound to the antigen distribured evenly over the entire surface of merozoites of P.falciparum,as demonstrated by immunoe:ectron microscopy.The McAb C6 also recognized a single protein of 71 kDa of P.falciparum by Western blotting.This antigen might be a candidate of malaria vaccine.

PRELIMINARY STUDY ON THE ROLE OF MACROPHAGE IN PROCESSING AND PRESENTING ANTIGENS OF SCHISTOSOMA JAPONICUM

1992, 10(3):  187-189. 

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The horseradish peroxidase labeled affinity purified mice anti-UEA (Urea soluable egg antigen of Schistosoma japonicum) antibody was used in enzyme-linked immunoe ectrotransfer blot (EITB) te monitor the changes after UEA being processed by Mφ.The immune respon-sive peptides were delected in the culture supernatant and homogenate of Mφ pulsed with UEA in vitro (Mφ+).After processing by Mφ the high molecular weight UEA was cleaved into low molecular weight peptides,as shown,by the reactive bands.They markedly differed from that native UEA or trypsin-digested UEA; The bands of Mφ supernatant and homogenate showed similarity with certain quantitative differences.According to the result described above,we considered: 1.UEA could be processed into smaller pieces by Mφ,the style of processing is cleavage.2.The processed peptides might be released to extracellular environment.

COMPARATIVE STUDY ON ANTIGENICITY AND IMMUNOGENICITY OF THE 24-26 kDa ANTIGEN AND THE RECOMBINANT Sj26 ANTIGEN OF SCHISTOSOMA JAPONICUM

1992, 10(3):  190-193. 

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This paper reports on the comparison of the recombinant Sj26 (rSj26) antigen originated from the Philippine strain and 24-26 kDa antigen isolated and purified from Chinese mainland strain of S.japonicum for their antigenicity and immunogenicity.The results showed that there were obvious cross reactions between rSj26 and 24-26 kDa anitigen when rSj26 antigen was tested against specific antibodies in sera from mice infected with the mainland strain of S.japonicum or 24-26 kDa antigen was tested against specific anti-rSj26 antibodies by ELISA,IFA and Western blotting etc.Both of 24-26 kDa and rSj26 antigen had weak cross reaction With SEA antigen.The worm reduction rate after challenging with mainland strain cercariae in mice immunized with rSj26 was 26~32%,similar to that in mice immunized with 24-26 kDa antigen.It is suggested that rSj26 antigen can induce certain level of specific protective immunity to protect the host against infection by Chinese strain of S.japonicum cercaciae.

ROLE OF HUMAN AND DOMESTIC ANIMAL RESERVOIRS OF SCHISTOSOMIASIS JAPONICA IN DONGTING AND BOYANG LAKE REGIONS

1992, 10(3):  194-197. 

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In Dongting and Boyang Lake regions,the main reservoirs of schistosomiasis were farm cattle (mostly buffaloes),pigs and mobile nonnatives.However,the role of these reservoirs in different types of endemic areas were not the same in the transmission of schistosomiasis In islet-beach type area,the main infectious sources were pigs and local residents.The proportion of IRC (Index of Real Contamination) of local residents and pigs to the total IRC was 30.9% and 39.9% respectively.In fork-beach type area having luxuriant grass and abundant aquatic products,there were a number of buffaloes and people from other places.The proportion of IRC of the normative buffaloes and mobile nonnatives made up 51.9% and 21.8% of the total IRC respectively,the main reservoirs being from other places.The embankment-beach type area had a vast snail-infested area and a large number of buffaloes from both local and other places as well as mobile nonnatives.The proportion of IRC of buffaloes and nonnatives made up 69.8% and 21.4% of the total IRC respectively,serving as the main reservoirs.As regard to season differences,the infected buffaloes were the main reservoirs during dry seasons,especially from March to May,whereas the mobile nonnatives including fishermen and boatmen were the main infectious sources during flood seasons from June to October.

SENSITIVITY IN VITRO OF PLASMODIUM FALCIPARUM TO CHLOROQUINE, PYRONARIDINE, ARTESUNATE AND PIPERAQUINE IN SOUTH YUNNAN

1992, 10(3):  198-200. 

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The sensitivity of P.falciparum to chloroquine,pyronaridine,artesunate and piperaquine (CQ,PD,AT,PQ) was assayed using in vitro microtechnique in south Yunnan in 1990.The resistance rates were 98.7% (75/76),27.6% (16/58),13.8% (9/65) and 97.7% (43/44) respectively,and ID50 were 125.0,19.0,4.7 and 243.3nmol/L,respectively.The resistance rate against CQ showed no change as compared to the rates against CQ 5 and 9 years ago;but the ID50 was lower.CQ-resistant P.falciparum showed a marked cross-resistance to PQ,but not to PD and AT.AT-resistant P.falciparum exhibited cross-resistance to the above-mentioned three drugs.PD-resistant P.falciparum showed no cross resistance to AT,but showed cross resistance to CQ and PQ.In comparison with chloroquine-coated plates,the plates coated with pyronaridine,artesunate or piperaquine gave similar results as the former,which were shown by the rise in schizont inhibition rates along with the rise in drug concentration.It indicates that pyronaridine-,artesunate-,and piperaquine-coated plates can be used in the assay of sensitivity of p.falciparum to the three drugs.

STUDIES ON THE STRAIN DIFFERENCES OF SCHISTOSOMA JAPONICUM IN THE MAINLAND OF CHINA. X. COMPARISON OF SDS-PAGE PROTEIN PATTERNS

1992, 10(3):  201-203. 

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The purpose of the present study was to investigate the SDS-PAGE separation of proteins of the 5 different isolates of Schistosoma japonicum from the mainland of China to determine their similarities and/or differences and to gain additional data which could give an added insight into the degree of relationship.Soluble proteins of freshly sonicated adult worm extract of the 5 different isolates (i.e..Anhui,Hubei,Guangxi,Sichuan and Yunnan) were compared by SDS-polyacrylamide gel electrophoresis.The results indicated that no marked difference could be observed among the isolates after gels were stained by Coomassie blue while both male and female worms of Guangxi isolate showed some definite differences in their protein profile,i.e.,Jack of 5075 kDa band in male worms and a marked reduction in the quantity of 110 and 30 kDa bands in female worms as shown by silver stain.

EFFECT OF SODIUM ARTESUNATE ON PLASMODIUM YOELII ANALYSED BY FLOW CYTOMETRY

1992, 10(3):  204-207. 

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The effect of sodium artesunate on Plasmodium yoelii-infected mouse erythrocytes was analysed by flow cytometry.The results showed that malarial DNA content in experimental group was obviously decreased 2-5 hours after the drug was administered,fluorescence distribution of malarial DNA almost disappeared within 24 hours after the administration.Thus we deem that sodium artesunate can inhibit the DNA synthessis in P.yoelii.

OBSERVATION ON THE EFFECTIVENESS OF REPELLENT COATING AGAINST MOSQUITOES

1992, 10(3):  208-210. 

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The present paper reports on the effectiveness of a repellent coating for the first time;.The repellent coating was made by combining DETA (N,N-diethyl-meta-toluanide) with slow-releasing reagent.With this coating employed in the laboratory against Aedes aegypti,the rate of blood-sucking was 3.9-9.5% and the rate of protection was 88.9-95.3% for 1-720 days.During 1-77 days' field trial,the RPI (Relative Population Index) was 0-8.98% in the day-time and 0.74-17.15 during the night-time against Anopheles sinensis,Culex pipiens pollens and Culex tritaeniorhynchus.It is concluded that the repellent coating is effective against mosquitoes,safe and prolongs the protection time following exposure to mosquitoes.

COMPARISON OF MOSQUITO LARVICIDAL EFFICACY BETWEEN MICROBIAL ENCAPSULATED BTI (EBTI) AND STANDARD BTI (SBTI)

1992, 10(3):  211-214. 

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A comparative study was conducted on the efficacy of mosquito larvicides EBTI and SETI.The results showed that: 1.The residual efficacy of EBTI was remarkably higher than that of SBTI at 0.007-0.002ppm BTI concentration (P0.01),the mosquito larvae mortality of EBTI remained 100% until the 4th week; in contrast,the mosquito larva mortality of SBTI gradually and obviously declined from the 2nd to 4th week after treatment (x2=8.17-24.08),and reached 0 at the 4th week.2.The lowest BTI concentration of EBTI at which a high efficacy persisted for 4 weeks was 0,007ppm BTI,the mosquito larva mortality remaining 100%.

TOXOPLASMIC RETINOCHOROIDITIS

1992, 10(3):  215-218. 

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Retinochoroiditis is a frequent occular lesion in toxoplasmosis.It may be severe,and even lead to blindness.Sixteen cases of toxoplasmic retinochoroiditis verified through IFA were presented in this paper.Among these cases,1 was of the multifocal type,its appearance being similar to that of the Coats disease; while the other 15 were of the focal type resembling to the central exudative retinitis (Rieger disease) or retincchoroidal scar; Serological finding of all the cases showed a positive IFA titre of1:80.A combination of pyrimethamine and sulfadiazine as well as spiramycin in addition to dexunethasone had been administered and proved effective.Since toxoplasmosis mostly cccurs as latent and examination of the eye cannot differentiate from other causes of retincchoroiditis,so such cline ical report of toxoplasmic retinochoroiditis was rare with particular reference in our country: The authors claimed that any individual presenting with retinochoroiditis suspected of toxo plasmosis should be subjected to serologic antibody test for establishing diagnosis.

OUTCOME OF GESTATION OF 32 PREGNANT WOMEN WITH TOXOPIASMA AND CYTOMEGALOVIRUS INFECTION

1992, 10(3):  219-221. 

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In an attempt to investigate the harmful effects of the infection of Toxoplasma and associated with cytomegalovirus on the fetus infection acquired transplaceatally during their mo- thers' pregnancy sera from 1000 pregnant women were tested for antobodies to both pathogens and the circulating antigen of Toxoplasma by using ELISA.The test was positive (titre≥1: 60400) in 32 of 1000 cases.Judging from the sero-positive results together with the case history,clinical manifestations and B-scan results,the 32 cases were edvised to end their pregnancy.Necropsy and pathological examinations of the foetuses revealed stillborn foetus,hy-drccephalus,acephalus,pleural effusion,ascites and other congenital malformations.Toxoplasma gondii were found in the tissues of 21 fetuses.

OBSERVATION ON METACERCARIAE OF PARAGONIMUS WESTERMANI BY TRANSMISSION ELECTRON MICROSCOPY

1992, 10(3):  222-224. 

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The ultrastructure of metacercariae of Paragonimus westermani was observed by transmission electron microscopy.The worm is composed of integument,parenchyma,gut and excretory sac.The integument consists of tegument,muscular layer and tegumental cell.The tegument,a syncytium,includes tegumental membrane,tegumental cytoplasm,and basal plasma membrane.On the surface of the tegument,many finger-like processes with branches and spines can be readily idendified.The spines projecting beyond the surface of the tegument are completely enclosed within the outer tegument membrane and the basal plasma membrate; in the transverse section,the spine shows a crystalline lattice structure.The tegumental cytoplasm consists of an electron dense granular matrix,in which two types of inclusion bodies,spherical and rod-like bodies may be recognised,both of them comprise a unit membrane and dense granular contents,the rod-like bodies are arranged along the edge of the spines.The tegument nuclei are located not within the surface syncytium but within sunken tegumental cells situated beneath the muscle layer,the tegumental cells contain a few cell organelles,and the two types of characteristic tegument inclusion bodies.The cells are joined to the tegument by one or more long,tortuous cytoplasmic tubules,responsible for the synthesis of the tegumental inclusion bodies,and that these inclusion bcdies are transloested into the tegument by the cytoplasmic tubules.It suggests that the tegument of metacercaria is the main absorptive site of nutrients.

SCANNING ELECTRON MICROSCOPIC OBSERVATI ON ON DEMODEX BREVIS

1992, 10(3):  225-226. 

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This paper presents the first description of the morphology of Demodex brevis examined by scanning electron microscopy.The authors found that D.brevis can be distinguished from D.folliculorum by the characteristic features of the following structures: the flat gnatho-soma,the humplike podosoma and the absence of transverse striation on its anterior dorsal Surface,the suprecoxal spines,the hypostome,the oral opening,the pedipalpal claws and the claws on legs,and the ennuli of the terminal part of the opisthosoma.The morphology of the above structures observed are briefly compared with those of D.folliculorum.

EXPERIMENTAL STUDY ON DETECTION OF SERUM ANTIBODIES BY IMMUNOENZYME STAINING USING ADULT ANGIOSTRONGYLVS CANTONENSIS FROZEN SECTION

1992, 10(3):  227-228. 

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This paper reported on the results of detection of serum antibodies in rats with Angiostro-ngylus cantonensis infection by immnoenzyme staining of adult frozen section.The positive rates of serum antibodies in rats 2 and 4 weeks after infection were 80% and 93.3%,respectively,The result of healthy control rats was negative.