Table of Content

30 November 1992, Volume 10 Issue 4

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ALTERNATION IN RESISTANCE OF PLASMODIUM FALCIPARUM TO CHLOROQUINE AFTER CESSATION OF CHLOROQUINE MEDICATION FOR TWELVE YEARS

1992, 10(4):  241-244. 

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In view of the fact the resistance of Plasmodium falciparum to chloroquine occurred extensively in Hainan,a decision was me.de in 1979 that the use of chloroquine should be quitted in the whole province.A longitudinal survey on chloroquine-sensitivity of P.falciparum was carried out during 1981-1991 to observe the variation in resistance of the parasite after the cessation of the chloroquine medication for every 2-3 years.A tendency of progressive decline of resistance was revealed.By using in vitor test,the rate of chioro-quine-resistant P.falciparum dropped from 97.9% in 1981 to 60.9% in 1991 (P0.001).The mean dosage of chloroquine for complete inhibition of schizont formation declined from 10.46pmol/μl in 1981 to 3.02 pmol/μl in 1991 (P0.001).The percentage of population requiring larger dosage (6.4pmol/μl to completely inhibit schizont formation declined from 83.3% in 1981 to 17.4% in 1991 (P0.001); whereas those requiring small dosage (1.6 pmol/μl),increased from 4.2% in 1981 to 60.8% in 1991 (P0.001).In in vivo test,the rate of chloroquine-resistant P.falciparum decreased from 84.2% in 1981 to 40% in 1991 (P0.001).The proportion of RⅡ plus RⅢ cases of the total resistant cases dropped from 59.4% in 1981 to 37.5% in 1991 (0.02P0.01).

STUDIES ON THE STRAIN DIFFERENCES OF SCHISTOSOMA JAPONICUM IN THE MAINLAND OF CHINA XI. ENZYME LINKED IMMUNOELECTROTRANSFER BLOT ANALYSIS

1992, 10(4):  245-249. 

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Antigens prepared from S.japonicum adult worms of different isolates i.e.Anhui,Hubei,Guangxi,Yunnan and Sichuen by origin were analyzed by enzyme linked immunoe-lectrotransfer blot (EITB) probed with rabbit anti-snail antibody (Figs 1,2).Anti-sera against Oncomelania h,hupensis from Anhui,Hubei,Yunnan and Sichuan localities were prepared separately and used in the tests.The EITB patterns were similar in S.j.isolates of Anhui and Hubei,and it was also the case among S.7.isolates of Yunnan and Sichuan except Yunnan female worms with a marked band of 84 kDa but it was almost invisible in EITB pattern of Sichuan female worms.Like Yunnan isolate,female worms of Guangxi isolate also showed marked 84 kDa bands.The EITB pattern of male worms from Guangxi isolate showed 2 main bands of mw130 kDa against anti-Anhui snail anti-serum,which corresponded with the male worms of Anhui isolate whereas the color of the bands was darker and denser in the former isolates,and these bands can not be seen in the male worms from isolates of Yunnan and Sichuan.Based on the above mentioned results in connection with the information about the susceptibility between different isolates of schistosemes and their snail hosts which we have reported before,some preliminary analysis and discussion were made.

STUDIES ON THE ESTABLISHMENT OF MALARIAL ANIMALMODEL OF SHORT-TERM RELAPSE II. THE PHENOMENONOF SUSTAINED SPECIAL RING FORM PARASITEMIAIN PLASMODIUM CYNOMOLGI INFECTION

1992, 10(4):  250-254. 

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Our previous report that the EE merozites of Plasmodium cynomolgi from Vietnam continuously released from the liver to the blood circulation was further demonstrated in this report.Monkeys were given pyronaridine 24mg/kg-d×6 after being inoculated intravenously with 32×105 sporzoites of P.cynomolgi.Thick blood film examination was conducted two times daily till the day when trophozoites were detected.Under the residual action of blood schizontocied,a special ring form parasitemia at low patasite-density was detected for more than 30 days.As the ring forms of P.cynomolgi were demonstrated to be susceptible to pyronaridine in our previous experiments,it might be infer red that these ring forms derived from EE merozites released not for once but continuously for 30 days or longer. Furthermore the special ring form parasitemia of infected monkeys after administration with M8132-derivative of dabequiae was also detected.We came to the conclusion just as in the case of pyronaridine.The variation in the ring form parasitemia was coincident with Verhulst model and might be described with the grey differential equation.The authors considered that the short-term relapse might be incuced by the later retease of EE merozoites which multiplied repeatedly in the blood after the drug was excreted and its action disappeared.

FIELD OBSERVATION ON THE POPULATION FLUCTUATION OF ONCOMEIANI A SNAIL AT LOW DENSITY IN PLAIN REGION

1992, 10(4):  255-257. 

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Field observation on the population fluctuation of Oncomelana snail at low density was carried out in the ditches and rivers in Wuxi,Ludong and Lugao counties (or city) from 1G87 to 1990.The results showed that the environment of the observed places is an important factor in the population fluctuation of the snails at low density.When the environment is appropriate,even one pair of the snails may multiply to a large populationResults of successive observation for 3 years on 1,5 and 10 pairs of snails within nylon cages in ditches showed that the density of the snails increased by 171.5,69.5 and 28.4 folds respectively and the population of the snails increased by 354,135 and 75 folds respectively.The population in 2 of the observed ditches with one pair of snails each even multiply by 543 and 426.5 folds.While in natural field condition,the population fluctuation of residual snails varied in different places.In one ditch it multiptied by 34.7 folds,but in another river the population almost unchanged.No natural elimination of snails could be found in all observed places.It was suggested that the snail surveillance should be conducted persistently and any snail once be found,it shou'd be timely eradicated.

STUDY ON THE EFFECT OF BROMOACETAMIDE UPON THE DEVELOPMENT OF SNAIL EGGS

1992, 10(4):  258-262. 

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This paper deals with the influence of bromoacetamide on the development of snail eggs,its effect on inducing diapause of snail eggs at different developmental stages (bkstula,gastrula,trochophore and veliger) both at different concentrations of bromoacetamide at the same time and at same concentration at different times.Besides,the oviposition of the snails and the eggs within snails have also been studied.The results are as follows: (1)When the snail eggs were immersed in bromoacetamide at concentrations of 0.034ppm-0.067ppm,deformation of snail eggs appeared from unicelluar to gastrula stages,but it was not observed after the trochophore-veliger stages.When the eggs at different stages were separately immersed in bromoacetamide,they were all found delormed.The molluscicidal concentration for inducing deformation of eggs was higher at the trochophore-veliger and metamophotic stages than that at the blastula and gastula stages (Figs.1-5)(2) After immersed in bromoacetamide solution,the development of the snail eggs were obviously retarded.The effects varied with different concentrations.Within the same exposure time,the higher the bromoacetamide concentration,the higher the diapause rate(3) The longer the immersion time,the lower concentration was needed to delay the development and the lower hatching rate was for the eggs at the same or different str.ges.(4)After treatment with bromoacemide,the average number of eggs laid by a female snail was reduced.(5)By using 3H-labered bromoacetamide,it was found that the radioativity of 3H-labeled bromoacetamide per hundred snail eggs was raised along with the increasing of the molluscicide concentration.It is concluded that direct exposure to low concentration of bromoacetamide could inhibit the development of snail eggs and obviously reduce the hatching rate.Furthermore,the chemical could enter the snail,damage the snail ovary and cause diapause of the snail eggs even though it could not kill the snail directly.It could also reduce the output of snail eggs and delay the reproductive period of the Oncomelania snail.

LEISHMAMASIS IN KARAMAY XI. THE DEVELOPMENT OF CUTANEOUS LEISHMANIASIS IN MONKEY AND MANEXPERIMENTALLY INFECTED WITH LEISHMANIA FROM KARAMAY BIG GERBIL*

1992, 10(4):  263-266. 

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A monkey (Maczca rhesus) was inoculated subcutaneously with 2 Leishmania isolates (MRHO/CN/88/KXG-2 and MRHO/CN/90/KXG-56) from Karamay big gerbils (Rhombomys opimus) into the forehead and cheek,36 days later ulceration with a diameter of 0.2cm occurred at 2 sites.The lesions persisted for 60 and 95 days respectively and then healed spontaneously.However,Leishmania could be detected from the dermal tissue for more than one year.When MRHO/CN/88/KXG-2 isolate was inoculated into the forearm or ear of the monkey,no ulceration but swelling was revealed at the sites of inoculation.Leishmania was found to be latent in the subcutaneous tissue of the forearm for more than 103 days.The monkey was dissected one year after inoculation,no evidence of visceral involvement was noted.Another isolate (MRHO/CN/87/KXG-12) was inoculated subcutaneously into the forearm of 2 healthy volunteers.One of them developed cutaneous leishmaniasis.An ulcer with a diameter of 0.4cm and a nodule as large as 0.9×1.5cm around the ulcer occurred at the inoculation site 128 days later.Leishmania parasites were found harboring in macrophages of the dermis and in the epithelial cells of hair follicles.The results indicate that Leishmania parasite of the Karamay big gerbils is pathogenic to monkey and man,in addition to the fact that human cutaneous leishmeniasis and gerbil's Leishmania co-exist in Karamay,it seems that big gerbil is a potential reservoir of human cutaneous leishmaniasis in this area.

DNA PROBE FOR IDENTIFICATION OF SIBLING SPECIES OF ANOPHELES SINENSIS AND ANOPHELES ANTHROPOPHAGUS

1992, 10(4):  267-270. 

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Genomic DNA libraries of Anopheles sinensis and Anopheles anthropophagus were constructed.The positive clones suitable for discrimination sibling species of An.sinensis and An.anthropophagus were screened and a clone from An.sinensis DNA library was ceceted and the insert DNA was used as a DNA probe to test dot blot of genomic DNA from An.sinensis and An.anthropophagus.The results showed that the DNA probe hybridized with all stages of An.sinensis DNA,but had very weak hybridization signal with An.anthropophagus DNA.The probe was very sensitive and could delect as little as 7.5ng An.sinensis which represents approximately one-150th part of the total DNA from single mosquito.The results demonstrated that the DNA probe reported here could be used to distinguish species of An.sinensis from An.anthropophagus.

SEROLOGICAL EPIDEMIOLOGIC SURVEILLANCE ON FILARIASIS BY ELISA

1992, 10(4):  271-274. 

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In 1984-1990 longitudinal or sectional serological surveillance on filariasis by ELISAwith Brugia malayi adult antigen was carried out in 6 villages,Yuhang County,ZhejiangProvince,where malayan filariasis had been under control.During that period the microfila-raemia rate of inhabitants had been declining continuously till nil,the positive rate andmean optical density (OD) value in ELISA for positive inhabitants concurrently declinedyear by year,especially for children under age of 10.By the 5th year after control boththe positive rate and mean OD value were close to those of healthy persons living in no-nendemic areas of filariasis,no positivity was found in children.In the meantime,ELISAwas used to detect serum antibodies in members of a family who were infected with ban-croftian filariasis and inhabitants living around them in 1990.Positive rate of ELISA was higher in these inhabitants (8.33%) than in healthy persons (2.53%),and positive oneswere detected from children under age of 10.The results suggest shat the detection of antifilarial antibody by using ELISA is an effective method for the surveillance of filariasis.

IN VITRO LIVER MICROSOMAL METABOLISM OF ANTIMALARIAL PRIMAQUINE

1992, 10(4):  275-278. 

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The profile of the major metabolites of primaquine produced by in vitro liver microso-mal metabolism was investigated with silica gel thin-layer and high performance liquid chro-matography (HPLC) analysis.The results indicated that the liver microsomal metabolism could simultaneously produce both 5-OH PQ (quinoline ring oxidation product) and CPQ (side-chain oxidative deamination product).However,the quantitative comparative study of microsomal metabolism showed that the production of 5-OH PQ was far much higher than that of CPQ.

CLINICAL OBSERVATION ON EFFICACY OF IVERMECTIN IN THE TREATMENT OF INTESTINAL NEMATODE INFECTIONS

1992, 10(4):  279-282. 

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A total of 166 cases were divided into 3 groups: group A comprised 55,group B 54 and group C 57 cases.Group A received ivermectin 0.1mg/kg orally at a single dore,the cure rates were 100%,3.8% and 50% for ascaris,hookworm and trichuris,infecfions respectively: group B received ivermectin 0.2mg/kg orally at a single dose,the corresponding cure rates were 95.5%,11.8% and 76.5% respectively; group C received pyrantel pamoate 10mg/kg orally at a single dose,the corresponding cure rates were 95.5%,29.6% and 31.6% respectively.Although the cure rates were very low for hookworm infection in both group A and B,however,a number of adult worms of Ancylostoma duodenale and Necator americanus were expelled aster medication; It indicates that ivermectin has some effects on these two species of human hookworm.Side effects were mild and transient in all groups.

DISTINGUISHING ANOPHELES DIRUS OF HAINAN PROVINCE BY GAS CHROMATOGRAPHY OF CUTICULAR HYDROCARBONS

1992, 10(4):  283-286. 

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In order to identify the members of Anopheles dims complex of Hainan Province,an analysis of relative content of cuticular saturated n-paraffins of Anopheles dirus collec- ted from different localities and in different months in Hainan Province was performed by using gas chromatography.The difference among the cuticular hydrocarbons n-pr.raffins components was atitistically insignificant.The values of stepwise cluster analysis (Q model) were very close for all the collected populations.These data suggested that there might be are species of Anopheles dims complex which was further confirmed by the similarities bet-ween blood preference,seasonal variation,and nocturnal activity.

HYBRIDIZATION EXPERIMENTS USING ANOPHELES MINIMUS FROM GUANGXI AND YUNNAN

1992, 10(4):  287-289. 

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Hybridization experiments were conducted by forced mating between Anopheles minimus from Guangxi (G) and Yunnan (Y).F1 hybrid females were all fertile with normally developed ovaries.(Y×G) F1 males were all sterile,with abnormally enlarged testes.(G×Y) F1 males,though fertile,showed somewhat atrophic testes,and when they were back crossed with parental females,the latter produced eggs with very low hatching rate.Ovarian nurse cell polytene chromosomes from F1 hybrid females showed partial asynapsis in X chromosome as well as in autosonles,asynapsis at 38 zone in 3L being the most constant.It was obvious that there was definite,though partial,reproductive isolation between An minimus from Guangxi and that from Yunnan.Whether they are sibling species remains to be further investigated (Figs.1-8).

STUDIES ON THE ANTIMALARIAL ACTION OF CEATIN CAPSULE OF ARTEMISIA ANNUA

1992, 10(4):  290-294. 

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The pharmacological and clinical effects of gelatin capsulae of Artemisia annua (GCAA) were investigated.The results revealed that the LD50 WP.S 162.5±10.1g (crude drug)/kg and ED50 was 11.9±2.4g (crude drug) for clearance of parasitemia in mice infected with Plasmodium berghei therapeutic index being 13.6,which was 3.5 times more than that of artemisinin.The cure rate of COEA for Plasmodium berghei and P.vivax infections was 100%,as well as just like that of the extract tablets of Artemisia annua and chloroquines This formulation was found to be better then chloroquine in fever subsidence and disape pearance of malarial symptoms,while the recrudescence rate was still high,the latter could be inhibited by increasing therapeutic course or daily dosing time or by combination wile primaquine.

IMMUNOHISTOCHEMICAL LOCALIZATION AND HISTOCHEMICAL OBSERVATION OF ANTIGENS IN PAGUMOGONIMUS SKRJABINI

1992, 10(4):  295-297. 

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Using immunohistochemical method,the antigens were shown to be mainly located in the cecum,tegument,esophagus,pharynx,excretory bladder,uterus and oral sucker of Pagumogonimus skrjabini.Histochemical analyses showed that antigens contained enzymes such as acid phosphatase (ACP),alkaline phosphatase (AKP),and acetyleholinesterase (AChE).Other chemical substances,for example,alkaline protein,basic protein,glycogen and acid mucopolysaccharides were also detected in the antigens of P.skrjabini.

OBSERVATION ON THE EARLY DEVELOPMENT OF INOCULATED BRUGIA MALAY I MICROFILARIAE IN MOSQUITOES

1992, 10(4):  298-300. 

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This paper reports the early development and variation of incculate Brugia malayi microfilariae in 3 groups of mosquitoes,i.e.young Anopheles sinensis,young Culex quin-quefasciatus and old Cx.quinquefasciatus.Significant differences were observed among these groups.Sixty hours after inoculation,the percentage of normally developing filarial larvae in young An.sinensis was 72.3%;the percentage of melanized microfilarise in young Cx.quinquefasciatus was 75.4% and the percentage of filarial larvae which deve-loped abnormally or remained in dispause status in old Cx.quinquefasciatus was 67.1%,each being much higher than that in the other groups.It was suggested that the immune competence of the mosquitces had influence upen the filarial development.The intensity of the immune response not only varied with the species,but also diminished with the aging of mosquitces

FURTHER OBSERVATION ON THE ULTRASTRUCTURE OF THE SPOROCYST OF SCHISTOSOMA JAPONICUM

1992, 10(4):  301-303. 

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A further observation was conducted on the ultrastructure of mother sporccyst (Ms),daughter sporocyst in the brood chamber (b-Ds),migrating daughter sporccyst (mi-Es) and daughter sporocyst in the liver tissue (1-Ds) of Oncomelania hupensis by scanning and transmission electron microscopy.There are 5 points worthy of mention here,namely:(1)A special structure,microvilli polymerizing cisterna,is found on the tegument of 52-day-old Ms branche in all directions and a tubule-like structure is connected to the matrix of the tegument,The significance of this structure may be dealed with the metabolism and transport of the parasite.(2) The tegumental spines appear on 52-day-old Ms.(3) The function of multilaminated vesicle in the tegument of 1-Ds may be associated with the turning over of the surface coat of the larvae and the copatibiltiy between parasite and molluscan host.(4) Abundant α-glycogen granules and mitochondria appear in the cytoplasm of parenchyma cell of brood chamber of Ms and Ds.It is proposed that the parenchymal cells not only served as the filling material,but also serve as the nursing cells for the regulation of asexual reproduction of the sporocysts.(5)The orientation of muscle fibers of the head of the mi-Ds and narrow node region of 1-Ds shows a well development of the inner longitudinal fibers adjacent to the outer circular muscle layer.They run anlero-posteriorly or vertically from the dorsal to the ventral.The pattern of muscle fibers may account for the activity of these regions of the parasite.(Figs 1-8)In short,the presentation of microvilli polymerizing cisterna,multilamilated vesicle,α-glycogen granules in parenchymal cell,the genesis of spine and the pattern of muscle fibers of the larval stage of schistosome might be helpful in understanding the asexual reproductive physiology of the parasite.

OBSERVATION ON ULTRASTRUCTURE OF STERILE CYSTS OF ECHINOCOCCUS GRANULOSUS IN MICE

1992, 10(4):  304-306. 

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The fine structure of sterile cysts of Echinococcus grcnulesus in mice was atudied by TEM.The cyst wall consists of laminated layer and germinal membrare At (?) level,the laminated layer contains microfibrillate matrix and irregularly shaped electron-dense granules.The germinal membrane comprise of tegument and cell region.Plasmalemma invagination resembling the "pinocytotic vesicle" are seen between the microtriches of the tegument,and mitochondria are seen in the basal portion of the tegument.In the cell region,there are tegumental cells,muscle cells,and glycogen-contafning cells."Nucleolar channel system" can be observed in some of the glycogen-containing cells.

PRELIMINARY OBSERVATION ON INFECTIVITY OF ISOLATED ALVEOLAR HYDATID AFTER CRYOPRESERVATION

1992, 10(4):  307-310. 

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Alveolar hydatids of Echinococcus multilocularis obtained from the peritoneal cavity of mice were subject to freezing at-10℃ and-30℃ respectively.After 130-200 days' storage,the alveolar hydatids were transferred into the mouse peritoneal cavity for viability and inactivity testing.It was found that the alveolar hydatids stored at-10℃ were more severely damaged than those stored at-30℃.The viability of the isolated alveococcus lasted half a year at-30℃.