bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of mast cell, basophil and eosinophil populations atHyalomma anatolicum anatolicumfeeding sites on cattle and the acquisition of resistance
Authors: Gill Harsharnjit S. 
Published: June 2009

SUMMARYThe cutaneous cellular reactions associated with aquisition of resistance by cattle toHyalomma anatolicum anatolicumfeeding were investigated by comparing the nature and sequence of cellular events atH.a. anatolicumfeeding sites following primary and tertiary infestations. Cattle acquired resistance toH.a. anatolicumfeedings after a single infestation. The resistance was manifested by a significant reduction in the mean weight of engorged females and mean weight of egg mass produced, failure to lay eggs and sometimes death of ticksin situ. The acquisition of resistance corresponded with pronounced epidermal vesiculation and a significant change in the nature of the cellular infiltrate at tick feeding sites indicating the development of cutaneous hypersensitivity. On primary infestation the cellular infiltrate was dominated by neutrophils (43–71%) followed by mononuclear cells (25–35%). Basophil and eosinophil infiltration in small numbers was noticed for the first time at 72 and 144 h, respectively, post-primary infestation. Unlike primary infestation, the dermal infiltrate on tertiary infestation, 24 h after attachment, was characterized by infiltration of basophils (6%) and eosinophils (3%) and a marked degranulation of mast cells and basophils. Basophils showed a consistent increase in absolute as well as relative numbers as the feeding advanced. They were the second most abundant cell types after neutrophils (48–68%) at 72 h (16%), and 144 h (23%). Eosinophils (3–9%) and mononuclear cells also showed a significant increase in their mean numbers as compared with primary infestation. There was a progressive decrease in the number of detectable mast cells following tick infestation and they were significantly lower post-tertiary infestation, compared to primary infestation. These results suggest that the pharmacological mediators released by degranulation of mast cells and basophils are perhaps the major effectors of resistance in cattle toH.a. anatolicum.
A scanning electron microscope study of the male copulatory sclerite of the monogenean Diplectanum aequans
Authors: Maillard C. , Gonzalez J. , Noisy D. 
Published: June 2009

SUMMARYThe cirrus of a monogenean Diplectanum aequans was isolated by treatment with sodium carbonate solution and studied with a scanning electron microscope. The method may be used in studies of the functional morphology and taxonomy of other organisms.
A comparative study of susceptibility of inbred and outbred mouse strains compared with hamsters to infection with New World cutaneous leishmaniases
Authors: Neal R. A. , Hale C. 
Published: June 2009

SUMMARYOne stock of each of Leishmania mexicana mexicana and L. m. amazonesis together with two stocks of L. braziliensis panamensis and L. b. braziliensis were tested for infectivity in inbred mouse strains Balb/c and CBA/H. The infectivity was compared with hamsters and the outbred CD1 mice. Balb/c mice were more susceptible than hamsters to L. mexicaba and L. braziliensis panamensis. Balb/c mice were not susceptible to L. b. braziliensis. CBA/H mice showed a low susceptibility to infection while CD1 mice showed an intermediate response
Schistosoma mansoni: migration and attrition of irradiated and challenge schistosomula in the mouse
Authors: Mastin Avis J. , Bickle Q. D. , Wilson R. A. 
Published: June 2009

SUMMARYThe fate of irradiated, immunizing cercariae and challenge schistosomula was investigated in mice using a quantitative, histological technique which would appear to be more efficient in estimating parasite numbers in skin and lungs than does the tissue mincing and incubation recovery technique used previously by other workers. There was evidence for slight retardation of irradiated (20 krad.) parasite migration in skin, but death of schistosomula in the skin appeared negligible. It was observed that the majority of irradiated parasites remained in the lungs until at least day 21 after infection, and that most schistosomula observed at this time were dead. In mice immunized with irradiated cercariae there was no evidence of attrition of the challenge infection in the skin. The migration profile of challenge parasites in the lungs of immunized animals was not significantly different from that of normal parasites in the lungs of naive animals. Dead challenge parasites were observed in the lungs but their numbers were not considered great enough to account for the final attrition measured by perfusion. It is suggested that the remainder of the attrition of challenge schistosomula may occur in the systemic and/or hepatic portal circulation.
Effects of alcoholic extract from Ma-Klua (Diospyros mollis) on adults and larvae of the dwarf tapeworm, Hymenolepis nana in mice and on the infectivity of the eggs
Authors: Maki Jun , Kondo Asami , Yanagisawa Toshio 
Published: June 2009

SUMMARYThe anthelmintic effect of an alcoholic extract from a shrub, Diospyros mollis, popularly known as Ma-Klua in Thailand, on the adults and larvae of the dwarf tapeworm, Hymenolepis nana, in mice was studied in comparison with that of flubendazole. The experimentally infected mice were given a single oral dose of 10–1000 mg of Ma-Klua extract or flu-bendazole/kg body wt 1, 2, 3, 4, or 12 days post-infection and autopsied 14 days post-infection. Ma-Klua extract was effective in the elimination of adults (ED50 = 79 mg/kg) but not larvae. Drastic effects of Ma-Klua extract on the motility and structure of adults were observed and the number of the adults in mice decreased with time after administration of the drug 12 days post-infection. The small numbers of adults remaining in the host intestine 2 days after the drug administration showed severe damage in the gravid segments. These facts were thought to be responsible for the significant reduction in egg output observed 1 and 2 days after medication. Fresh eggs exposed to Ma-Klua extract in vitro and in vivo, or in vivo alone showed reduced infectivity. The effect of flubendazole on adults and larvae was minimal.
Ultrastructural studies on the cellular response of fish hosts following experimental infection with the plerocercoid of Ligula intestinalis (Cestoda: Pseudophyllidea)
Authors: Hoole D. , Arme C. 
Published: June 2009

SUMMARYWith the exception of gudgeon (Gobio gobio) infection of cyprinid fish with the plerocercoid of Ligula intestinalis is associated with a host-tissue response. The nature and specificity of this response has been investigated using transplantation techniques. In roach there is an intense cellular response to implanted Sepharose, Spurr's resin and L. intestinalis, irrespective of donor host species. However, tegument damage only occurs in gudgeon-Ligula and cultured ro&ch-Ligula which has been exposed to gudgeon-plasma. L1 and L2 cell types predominate within the cellular response. Once the host leucocytes have breached the tegument, they migrate over the basal lamina and penetrate into the sub-tegumental region. In gudgeon an intense cellular attack occurs against Sepharose, Spurr's resin, ro&ch-Ligula and cultured gudgeon-Ligula which had been implanted directly or exposed to roach plasma. Tegument damage only occurs in the latter. In contrast, neither direct implantation of gudgeon-Ligula nor cultured roach-Ligula which has been exposed to gudgeon plasma evokes a cellular response. It is suggested that in these two instances, as in natural infections of gudgeon, protective host proteins may be absorbed onto the surface of the parasite.
Unikaryon slaptonleyi sp.nov. (Microspora: Unikaryonidae) isolated from echinostome and strigeid larvae from Lymnaea peregra: observations on its morphology, transmission and pathogenicity
Authors: Canning Elizabeth U. , Barker Rosalind J. , Hammond Jill C. , Nicholas J. P. 
Published: June 2009

SUMMARYA microsporidium, isolated from echinostome and strigeid larval trematodes in Lymnaea peregra, is described as a new species Unikaryon slaptonleyi sp.nov. The nuclei isolated at all stages of development, the disporoblastic sporogony and development in contact with host cell cytoplasm are used to assign the species to the genus Unikaryon. The absence of a vacuolar membrane to isolate the meronts and stages of sporulation from the host cell cytoplasm differentiates this genus from Encephalitozoon. Spores are uninucleate, have 17–21 turns of the polar filament coil and measure 5·0 × 2·8/μm fresh. U. slaptonleyi was isolated from rediae and metacercariae of Echinoparyphium recurvatum and sporo-cysts and cercariae of an unidentified strigeid trematode in L. peregra. It was transmitted in the laboratory to unidentified echinostomes in L. peregra and to unidentified strigeids in Planorbis planorbis by feeding the spores to field-collected snails from which cercariae were already emerging. In these natural and experimental hyperinfections the snail tissues were lightly infected but, in the helminths, much of the parenchyma and germinal tissue was destroyed, so that few cercariae were released and most of those were distorted. Similar heavy infections were produced in Fasciola hepatica in Lymnaea truncatula, when spores were fed to the snails 14 days after miracidial penetration, but even high doses (106 spores/snail) produced only light infections in Schistosoma mansoni in Biomphalaria glabrata, in only 2 out of 9 snails. No infections were obtained in larvae producing xiphidiocercariae in P. planorbis although echinostomes became infected under the same conditions. Of a number of aquatic and terrestrial arthropods tested for susceptibility by feeding or by inoculation of spores into the haemocoele, only Pieris brassicae became infected. In a small proportion of pupae surviving from larvae which had been inoculated with spores at 3rd or 4th instar, there was clear evidence of spore replication.
Junctional complexes in the inner cyst tissue of the cysticercoid ofHymenolepis diminuta(Cestoda)
Authors: Richards K. Sylvia , Arme C. 
Published: June 2009

SUMMARYThe inner cyst tissue development is anteriad and centripetal. The cells produce lamellar extensions which assume parallel alignment. The first contact points (approximately 4 days post-infection) establish heptalaminar (gap) junctions. Lamellar attenuation results in a decreased intercellular space, and at 5–6 days pentalaminar junctions (with fused outer plasmalemma leaflets to give an electron-dense, approximately 3 nm wide O–O line) occur. This is the first maturation (Ml) stage. The O–O lines are permeable to lanthanum, and evidence of their possible transformation from heptalaminar junctions is presented. Continued lamellar attenuation, associated with scolex retraction and subsequent growth, results in cytoplasmic occlusion and contact between the inner leaflets of thesamelamella. The resultant electron-dense I–I line is approximately 3 nm wide; the O–O line is now less electron-dense and thinner (approximately 2 nm). This final maturation (M2) stage, resembling vertebrate myelin, occurs over limited areas; closely adjacent regions either remaining at the M1 stage, or not displaying junctional complexes. Sincein vivoandin vitroexcystment can occur before the M2 stage, the inner cyst tissue is not considered to be protective against the definitive host. That the tissue may function in limiting nutrient flow, thus regulating the size of the presumptive adult, is discussed.
Schistosoma mansoni: tail loss in relation to permeability changes during cercaria–schistosomulum transformation
Authors: Howells R. E. , Gerken S. E. , Pinto-Ramalho F. J. , Kawazoe U. , Gazzinelli G. , Pellegrino J. 
Published: June 2009

The hind-body region of Schistosoma mansoni cercariae observed in the scanning electron microscope demonstrates various stages of contraction which may be compared with those of living larvae which are secreting the acetabular gland contents.No evidence for an extensive lesion was found in cercarial bodies which had shed their tails under experimental conditions. Experiments on the permeability of the larvae to sodium fluoride, methylene blue and amino acids demonstrated that tail loss significantly affects the permeability of the bodies although the effect is greater immediately after decaudation than at later times. Subsequent increases in permeability may be correlated with a change in the general body surface.
Assessment of the human and ecological hazards of microbial insecticides
Authors: Harrap K. A. 
Published: June 2009

SUMMARYA comprehensive account is given of the evolution of registration guidelines and safety testing procedures for microbial insecticidal agents. Particular emphasis is given to the use of viruses for pest control and the various guidelines developed to assess their possible hazards. The likely gains and risks associated with using viruses are discussed. Several meetings have been held in the last 10 years to assess the hazards of virus insecticides. Some of these meetings have produced recommendations, some have developed guidelines for safety testing. These meetings are reviewed. The various guidelines developed for safety testing are critically evaluated and the UK Registration Criteria for Biological Agents used as Pesticides are reproduced in full. Examples of viruses that have been safety tested and registered for use are given and the criteria used are described. Conclusions are drawn on the merits of the guidelines presently available and the likely future development of safety testing schemes is considered.
Population interactions between a parasitic castrator,Probopyrus pandalicola(Isopoda: Bopyridae), and one of its freshwater shrimp hosts,Palaemonetes paludosus(Decapoda: Caridea)
Authors: Beck J. T. 
Published: June 2009

SUMMARYFreshwater shrimp,Palaemonetes paludosus, infected by the bopyrid isopod,Probopyrus pandalicola, occurred as far as 33 km upstream in many coastal rivers and canals throughout Florida. Free-swimming isopod larvae and the intermediate copepod host,Acartia tonsa, were collected in the plankton of the Wakulla River, and it appeared that cryptoniscus larvae swam at least as far as 13 km upstream to infect the definitive shrimp host after leaving the copepod in brackish water. In the Wakulla River infection levels ranged from 87·5 to 100%. In contrast, at McBride's Slough infection levels fluctuated from 0·9 to 93·2%. In the St Marks River the frequency of infected shrimp gradually increased from 0% upstream to 96%, 6 km further downstream. A significantly greater percentage of female than male hosts were infected, but only females of size classes less than 31 mm long had a greater frequency of infection. FemaleP. pandalicolawere greatly under-dispersed (coefficient of dispersion (s2/x¯) less than 1) throughout the host population; 99·6% of the infected hosts carried only 1 female parasite. Control ofP. pandalicolaat the infrapopulation level is probably accomplished by some mode of intraspecific competition, and control at the suprapopulation level occurs through an upstream limitation of the transmission range of the cryptoniscus larval stage. Host–parasite interactions appear to be unstable.
Immunity toSchistosoma mansoniin congenitally athymic, irradiated and mast cell-depleted rats
Authors: Ford M. J. , Bickle Q. D. , Taylor M. G. 
Published: June 2009

SUMMARYImmunity toSchistosoma mansoniwas investigated in congenitally athymic (Nu/Nu) rats, irradiated rats and in mast cell-depleted rats. Nu/Nu rats failed to develop significant resistance following vaccination with irradiated cercariae, although Nu/Nu recipients of serum from vaccinated Fischer rats (VRS) manifested resistance comparable to heterozygous controls, suggesting that T-cells were required in the induction of resistance but were not involved in the efferent arm of antibody-dependent elimination. Radiosensitive cells (including eosinophils, basophils, neutrophils, lymphocytes and mast cells) were apparently not essential for the antibody-dependent elimination of lung or post-lung stages since irradiated (700–750 rad.) recipients of VRS manifested comparable degrees of resistance to unirradiated controls in spite of a greater than 85% reduction in total blood leucocyte counts after irradiation. Depletion of 99 % of tissue mast cells by treatment of rats with Compound 48/80 had no significant effect on the attrition of a challenge infection in rats rendered immune by vaccination with irradiated cercariae or by transfer of VRS. However, there was a significant increase in worm recovery in unimmunized and mast cell-depleted or irradiated rats, indicating that mast cells and perhaps other radio-isotope sensitive cells may be involved in innate resistance.
Genomic cloning of human Echinococcus granulosus DNA: isolation of recombinant plasmids and their use as genetic markers in strain characterization
Authors: Rishi A. K. , McManus D. P. 
Published: June 2009

SUMMARYA small, size selected (0·5–5·0Kbp) genomic DNA library has been constructed in the bacterial plasmid pAT153 using DNA extracted from a human isolate (Kenyan origin) of the hydatid disease organism, Echinococcus granulosus. A panel of taeniid cestode DNAs has been used in conjunction with hybridization and restriction-enzyme analysis to identify in the library two recombinant plasmids with Echinococcus-specific inserts and a single recombinant plasmid (coded pEG18) with a DNA fragment unique for E. granulosus. These, and other recombinant plasmids with E. granulosus DNA inserts, have been used in restriction endonuclease, Southern transfer and hybridization analysis to independently and repro-ducibly discriminate between the UK horse and sheep strains of E. granulosus; these probes may well prove of value for characterizing isolates from other endemic areas. The feasibility of using a cloned DNA fragment as the basis of a simple field test for distinguishing eggs of E. granulosus from those of other taeniid cestodes is discussed. The recombinant insert (approximately 2·3 Kbp in size) of pEG18 has a low copy number - estimated at approximately 26 - and it may not be sufficiently sensitive for practical use as a DNA probe in the identification of small numbers of E. granulosus eggs by molecular hybridization.
Functional morphology of the metacercarial cyst of Bucephaloides gracilescens (Trematoda: Bucephalidae)
Authors: Halton D. W. , Johnston B. R. 
Published: June 2009

SUMMARYThe metacercarial cyst wall of Bucephaloides gracilescens is bilayered. It comprises an inner granular layer of pepsin-resistant carbohydrate and protein material secreted by the parasite, and an outer fibrous and cellular capsule susceptible to pepsin digestion and elaborated by the host. The capsule of cysts from the orbits and nasal regions of the whiting host are substantially thicker than those from the cranial cavity. Cells in the outer portion of the capsule resemble fibrocytes engaged in the synthesis and secretion of collagen; collagen fibres form a loose meshwork in the intercellular space. The cells incorporated [3H]proline in vitro, but not [3H]tyrosine. The cells of the inner portion of the capsule are closely packed and possess pyknotic nuclei; desmosomes and cytofilaments are numerous and probably impart strength and elasticity, respectively, to the cyst wall. Host cells are necrotic at the interface with the inner cyst wall, possibly due to compression or isolation from oxygen and nutrients. Differences in the levels of incorporation of trace-labelled substrates by encysted metacercariae were related to the site of infection and to the thickness and permeability of the cyst wall.
The influence of water temperature and pH on the survival of Fasciola hepatica miracidia
Authors: Smith G. , Grenfell B. T. 
Published: June 2009

SUMMARYExperimental studies on the survival of Fasciola hepatica miracidia show no evidence that miracidial mortality varies with the pH of the medium, at least in the range 6·0–8·0. On the other hand, miracidial mortality is shown to vary with both the temperature of the medium and the age of the larvae. The mean expected life-span of the miracidium decreases from about 35 h at 6°C to about 6° h at 25° C. The Gompertz survival function provides a good description of the miracidial survivorship curves over the range of temperatures used, and we describe, a maximum likelihood method of estimating the mean values of the parameters of this function, together with their approximate 95% confidence limits.
Borrelia crocidurae localization and transmission in Ornithodoros erraticus and O. savignyi
Authors: Gaber M. S. , Khalil G. M. , Hoogstraal H. , Aboul-Nasr A. E. 
Published: June 2009

SUMMARYBorrelia crocidurae infection rates in different organs of adult Ornithodoros (Pavlovskyella) erraticus and O. (Ornithodoros) savignyi were studied at intervals during a 60-day period following an infective meal. The spirochaetes persisted in tick guts for 1 month, were first observed in other organs 1–7 days post-feeding, and persisted for 20–60 days in different organs. The ovaries, Gene's organ, testes and male accessory glands of only O. erraticus were infected. The infection rates in adult and immature O. erraticus and O. savignyi post-feeding on infected hamsters were 26·7–60·0% and 26·7–80·0%, respectively. Spirochaete trans-stadial transfer from originally infected larval O. erraticus to first-instar nymphs (N1) was 33·3%; to subsequent N2–N5 it was 40·0–60·0%. Infection rates in the resulting adults were 26·7% (males) and 46·7% (females). In O. savignyi, trans-stadial transfer from originally infected N1 to N2 was 26·7% and to subsequent N3–N7 13·3–33·3%; of the resulting males and females, 20·0% were infected. Transovarial transmission from female O. erraticus infected as adults occurred after the second gonotrophic cycle to 33·3–53·3% of the F1 larvae, and to 26·7 and 46·7% of the F1 males and females, respectively. All infected F1 females transmitted the spirochaetes to 26·7–73·3% of the F2 larval progeny after the first gonotrophic cycle. Transovarial transmission was not observed in O. savignyi.
Observations on the ability of repeated, light exposures toSchistosoma mansonicercariae to induce resistance to reinfection in Kenyan baboons (Papio anubis)
Authors: Sturrock R. F. , Cottrell B. J. , Kimani R. 
Published: June 2009

SUMMARYUsing groups of 4 baboons (Papio anubis), 21·0% of a trickle exposure of 480Schistosoma mansonicercariae/baboon (10/week for 48 weeks) were recovered as adult worms (Group A) compared with 72·6% from a single massive exposure of 2500 cercariae/baboon (Group C). Group B, exposed first to the trickle and then to the massive exposure simultaneously with Groups A and C, yielded a worm recovery of 54% which was slightly but significantly less than Group C. The trickle infection apparently induced a substantial resistance to light re-exposure, but only a partial, although significant, resistance to a massive re-exposure. In Group B, however, there was a marked reduction in the degree of gross pathology, despite high tissue egg production by the mature challenge worms. The parasitological results, in terms of resistance to reinfection by and development of pathology to a trickle infection, are not materially different from those obtained in studies using conventional heavy primary and challenge exposures withS. mansoni. The significance of these findings is discussed in relation to the epidemiology of human schistosomiasis mansoni in which heavy exposures are believed to be the exception rather than the rule.