Pairing of Schistosoma mansoni males in infected Syrian hamsters

Pairing of male schistosomes in the liver of infected hamsters was recorded with Egyptians S. mansoni strain. The homospecific male pairs never carried each other in the gynaecophoric duct, but they being closed in either central or hepatic veins. Other perfused males and females en copula showed normal mating behaviour. The paired males were more or less in the same size. The random sexed miracidia used resulted in obtaining 1:2.1 female/male ratio. It is concluded that the random increase of male schistosomes may create the male pairing behaviour. Also, the migration of female against the blood stream to the mesenteric plexus of the host and the failure of male to catch them may lead to this homosexual pairing. The black haemozoin-like substance seen in mature females was also observed in the pairing males and this probably reflects the effect of scarcity or migration of females to the mesenteric plexus.     

The histopathological picture of the liver of hamsters experimentally infected with Leishmania D. infantum on top of Schistosoma mansoni infection

No doubt, double and triple infection in a patient is not an uncommon phenomenon in the Old World. Consequently, the histopathological picture of the liver of Syrian golden hamsters experimentally infected with Leishmania. d. infantum on top of pre-infection with S. mansoni was studied. The results showed that the liver was markedly affected by the concomitant infection than infection with either parasite alone. The superadded Leishmania infection caused the early appearance of cell necrosis and fatty changes. The schistosomal granulomas were rounded in shape and well circumscribed. However, they were smaller in size and less in number when compared with schistosomal control. Also, there was a comparative decrease in the number of their cellular constitutions but without changing in the cell types. The schistosomal granulomas were surrounded with a rim of amastigotes laden macrophages. On the other hand, the leishmanial granulomas, were irregular in shape but comparatively increased in size and in number on the behalf of the schistosomal granulomas. Their cellular constitutions comparatively increased as well. So, it is concluded that the L.d. infantum infection on the top of S. mansoni infection suppressed the schistosomal pathological picture in the liver of hamsters.     

Effect of wide spectrum anti-helminthic drugs upon Schistosoma mansoni experimentally infected mice

An important issue of concern for drug analysis in hair is the change in the drug concentration induced by the cosmetic treatment of hair. The products used for this treatment are strong bases and they are expected to cause hair damage. As a result drugs may be lost from the hair matrix or, under conditions of environmental contamination, be more easily incorporated into the hair matrix. We investigated the effects of cosmetic treatment in vivo by analysing hair samples selected from people who had treated their hair by bleaching or dyeing before sample collection. All of the subjects admitted a similar drug consumption during the time period for which the strands were analysed. Samples were viewed under a microscope to establish the degree of hair damage. Treated and untreated portions from each lock of hair were then selected, separated and analysed by standard detection procedures for cocaine, opiates, cannabinoids and nicotine. In all cases the drug content in hair that had undergone cosmetic treatment decreased in comparison to untreated hair. The majority of the mean differences were in the range of 40%-60% (cocaine, benzoylecgonine, codeine, 6-acetylmorphine and THC-COOH). For morphine the mean difference was higher than 60%, and two cases (THC and nicotine) differed by approx. 30%. These differences depended not only on the type of cosmetic treatment, as bleaching produced higher decreases than dyeing, but also on the degree of hair damage i.e. the more damaged the hair, the larger the differences in the concentration levels of drugs.     

Detection of Schistosoma mansoni M antigen in circulating immune-complexes and in kidneys of infected hamsters

Circulating M antigen (CMA) of Schistosoma mansoni was found in the trichloroacetic acid (TCA) soluble fraction of a polyethylene glycol precipitate of serum from infected hamsters. It was also found as a TCA-soluble component in an immunoglobulin-containing fraction eluted from infected hamster kidneys. It was not found in similarly treated control sera nor in the products of acid dissociation of circulating immune complexes (CIC) from infected hamster sera. CMA was not detected in the kidneys of normal hamsters. Precipitating anti-M antigen antibodies were present in one of 10 sera from infected hamsters, but not in the eluates of hamster kidneys. These results indicate that CMA is present in circulating immune complexes in infected hamsters. The presence of CMA in kidneys from the same hamsters suggests a possible role for circulating antigens in immune-complexed form in the aetiology of glomerulonephritis in S. mansoni infection.     

Effects of induction of anti-embryonation and anti-fecundity immunity on liver granuloma formation in mice infected with Schistosoma japonicum

Coronal T2-weighted magnetic resonance imaging (MRI) has been reported to be a useful technique for the localization of both spontaneous and traumatic CSF (cerebro spinal fluid) fistulae. We reviewed the magnetic resonance imaging (MRI) scans of 50 patients with temporal lobe epilepsy in whom such sequences were routinely acquired to determine if this asymptomatic population fulfilled any of the criteria for the diagnosis of a CSF fistula. We found that a large proportion did and conclude that using MRI as the initial radiological investigation in the localization of CSF fistulae is of such low specificity that it is of little or no value.     

Vaccination of patas monkeys experimentally infected with Schistosoma haematobium using a recombinant glutathione S-transferase cloned from S. mansoni

The capacity of a recombinant glutathione S-transferase from Schistosoma mansoni (rSm28GST) to vaccinate primates (Erythrocebus patas) against a heterologous infection with Schistosoma haematobium has been tested. Two injections of the purified molecule with Muramyl-Di-Peptide (MDP) as adjuvant resulted in a high level antibody response in the five immunized animals and in a significant reduction in worm fecundity compared to the controls which received adjuvant alone. Mean levels of daily egg excretion in urine an faeces were reduced by respectively 55% and 74% although perfusion revealed that worm burdens were similar in both groups. The protective effect was long lasting since it was maintained up to the end of the experiment, 42 weeks after infection. Hatching rates and the numbers of intra-uterine eggs were also significantly affected by the vaccination. Tissue eggs were also drastically diminished in the urogenital system (-80%) but the reduction was not statistically significant. One animal was not protected by the immunization. There was a good correlation between parasitological data and the intensity of bladder lesions assessed by microscopic examination. Polypoid formations together with an intense exudation of the lamina propria were frequently seen in the controls but rarely in the vaccinated group where formation of scar tissue was predominant. These results underline the vaccine potential of the recombinant Sm28GST as a possible valuable prophylactic tool for the control of egg-induced pathology and transmission of African schistosomes.     

Studies on experimental mixed infection of Schistosoma haematobium and Schistosoma mansoni

Swiss Albino mice have been infected with S. haematobium and challenged 4 weeks later with S. mansoni. Parasitological, pathological and ultrastructural studies were done. The results revealed cross mating between the two species. A reduction in S. mansoni worm load, egg count, hepatic granuloma number and size was noticed. The presence of heterologous immunity was suggested.     

Effect of Schistosoma mansoni infection on offsprings born from infected mothers

Offsprings C57BL/6 mice (4 weeks old) coming from either moderately infected (40 S. mansoni cercariae) or heavily infected (100 S. mansoni cerariae) mothers, were exposed to 40 S. mansoni cercariae each. Seven weeks post infection (P.I.), Offsprings were sacrificed. In both groups there was significant reduction in the worm load, both hepatic and intestinal tissue egg count. The oogram profile was not altered. Humoral immune response as regards the level of anti S. mansoni SEA Ab was elevated in both groups in comparison to their parallel controls at 2 weeks post delivery and 7 weeks P.I. The level of antibodies was significantly higher in heavily infected Offsprings than that present in offsprings coming from moderately infected mothers. Delayed footpad swelling and hepatic granuloma size were significantly reduced in both groups comparing with their corresponding controls.     

Cellular constituent and intercellular adhesion in Schistosoma mansoni granuloma: an ultrastructural study

The present work deals with the structural analysis of Schistosoma mansoni granuloma and the visualization of cellular interaction at an ultrastuctural level in the acute (8 weeks) and chronic (20 weeks) stages of infection, for more detailed understanding of pathophysiology of the disease. Although, S. mansoni granuloma is mediated by T-lymphocytes, yet in this work the macrophage cells and not the lymphocytes represented the main cell type in cellular and fibrocellular granulomas. The cellular and fibrocellular granulomas detected in the acute stage of infection elicited no difference in cellular constituent to those of the chronic stage respectively. Macrophage cells and fibrocytes were the only cell type detected in fibrotic granuloma. The monocytes may be considered the first cell reaching the site of the trapped egg as they formed the first row of cells around the egg. The cellular infiltrate forming the granuloma: monocytes, macrophages, lymphocytes, eosinophils, fibroblasts and plasma cells revealed direct contact or adherence between them and even between the individual cell type, through extending protrusion from the cell membrane of adjacent cells. They constituted an integrated network which encircled the egg. Similar adhesion between inflammatory cells in the blood vessels and between the inflammatory cells and the endothelial cells were displayed. These points of intercellular adhesion appeared as if, not only used for functional communication between the cells, but also for cellular deplacement either in the extracellular matrix or in the blood stream until extravasation. In conclusion, S. mansoni granuloma is a highly organized cellular lesion, in which cell to cell communication occurs through direct cell contact.     

An ultrasonographic study of liver fibrosis in patients infected with Schistosoma mansoni in north-east Brazil

Between August 1988 and July 1990, 176 patients with Schistosoma mansoni infection attending the University Hospital, Recife, Brazil received a complete clinical examination including stool examination for intestinal parasites, liver function tests, and ultrasonography. The majority were also examined by upper digestive tract endoscopy. The clinical distribution of their disease was as follows: 26.7% intestinal, 13.6% hepato-intestinal, 53.4% compensated hepatosplenic and 6.3% decompensated hepatosplenic. Infection intensity was high, with a median of 360 eggs/g of faeces. Ultrasonography showed a good correlation between the degree of hepatic periportal fibrosis and the clinical stage of disease (P < 0.0001). Of the patients with the intestinal form of schistosomiasis, 12.8% had grade I fibrosis and the others had no fibrosis; 33.3% of patients with hepatointestinal schistosomiasis had grade I fibrosis, 8.3% had grade II fibrosis, and 58.4% had no fibrosis; all the patients with hepatosplenic disease had grade II or grade III fibrosis. The degree of liver fibrosis detected by ultrasonography correlated with the degree of oesophageal varices detected by endoscopy (P = 0.0001). The degree of oesophageal varices also correlated with the presence of haemorrhage (P < 0.0001). Ultrasonography is considered superior to liver biopsy, permitting a dynamic approach to the study of schistosomiasis morbidity with precise diagnosis and simple sequential follow-up of post-treatment results.     

Expression of class II, but not class I, major histocompatibility complex molecules is required for granuloma formation in infection with Schistosoma mansoni

Previous studies have suggested that granulomatous inflammation in schistosomiasis is mediated by CD4+ T helper lymphocytes sensitized to parasite egg antigens. However, CD8+ T cells have also frequently been associated with the immune response to schistosome eggs. To examine more precisely the role of CD4+ and CD8+ T cells in the pathology of the schistosomal infection, we used mice with targeted mutations in major histocompatibility complex (MHC) class II or class I molecules. These mutations lead, respectively, to the virtual absence of CD4+ and CD8+ T cells. The results clearly show that schistosome-infected MHC class II mutant mice failed to form granulomas around parasite eggs. In contrast, infected MHC class I mutant mice displayed characteristic granulomatous lesions that were comparable to those in wild-type control mice. Moreover, lymphoid cells from MHC class II mutant mice were unable to react to egg antigens with either proliferative or cytokine [interferon-gamma, interleukin (IL)-4, IL-10] responses; nor were they able to present egg antigens to specifically sensitized CD4+ T helper cells from infected syngeneic control mice. By comparison, cells from MHC class I mutant mice exercised all these functions in a manner comparable with those from wild-type controls. These observations clearly demonstrate that schistosomal egg granulomas are mediated by MHC class II-restricted CD4+ T helper cells. They also suggest that CD8+ T cells do not become sensitized to egg antigens and play little role, if any, in the pathogenesis of schistosomiasis.     

IL-13 is a key regulatory cytokine for Th2 cell-mediated pulmonary granuloma formation and IgE responses induced by Schistosoma mansoni eggs

Schistosoma mansoni egg-induced pulmonary granuloma formation is a cell-mediated inflammatory response associated with dominant Th2-type cytokine expression, tissue eosinophilia, and high levels of serum IgE. In the present study, we show that in vivo blockade of the Th2 cytokine IL-13, using soluble IL-13R alpha2-Fc fusion protein, significantly reduced the size of pulmonary granulomas in unsensitized as well as egg-sensitized mice. Blocking IL-13 also significantly reduced total serum IgE levels. Interestingly, however, IL-13 blockade did not affect the evolving egg-induced Th2-type cytokine response. IL-4, IL-5, as well as IL-13 responses were indistinguishable in control-Fc- and soluble IL-13R alpha2-Fc fusion protein-treated animals. The smaller granulomas were also phenotypically like the control Fc-treated mice, displaying a similar eosinophil content. Additional studies in IL-4-deficient mice demonstrated that IL-13 was produced, but at much lower levels than in wild-type mice, while IL-4 expression was completely independent of IL-13. Moreover, while granuloma formation was partially reduced in IL-4-deficient mice, blocking IL-13 in these animals almost completely abrogated granuloma development and the pulmonary eosinophilia, while it simultaneously increased IFN-gamma production. Together, these data demonstrate that IL-13 serves as an important mediator of Th2-mediated inflammation and plays a role in eliciting IgE responses triggered by schistosome eggs.     

Modification of the lung recovery assay for schistosomula and correlations with worm burdens in mice infected with Schistosoma mansoni

The kinetics of recovery of schistosomula from the lungs of previously-unexposed CF1 mice were studied following infection with Schistosoma mansoni cercariae. Lung tissue fragments were incubated from 3 to 48 hr and the completeness of recovery of viable schistosomula was determined. The recovery of schistosomula from the lungs was shown to correlate closely with 7-week worm recoveries. With the additional incubation described, the lung recovery assay may provide a more defined indicator of protective immunity. Based on the data generated by these analyses, it is predicted that under these conditions schistosomula arrive in the lungs from 3 to 7 days after infection, and that they sojourn there for a 3-day period.     

Tegument changes of Schistosoma japonicum and Schistosoma mansoni in mice treated with artemether

AIM: To study the effect of artemether (Art) on the tegument of schistosomes. METHODS: Mice infected with S japonicum cercariae for 7 and 35 d, or with S mansoni cercariae for 49 d were treated intragastrically with Art 200-300 mg.kg-1.d-1 for 2 d. Schistosomes were collected in groups of 2 mice at various intervals after medication for scanning electron microscopic observation. RESULTS: The tegumental changes induced by Art appeared to be similar in S japonicum and S mansoni: swelling and fusion of tegumental surfaces, vesicle formation and collapse of discoid-like sensory structures. In S japonicum the emergence of tegumental alterations was earlier in 7-d-old schistosomulae than that in 35-d-old adult worms. CONCLUSION: Art injured the teguments of S japonicum and S mansoni.     

Effects of immobilization restraint on Syrian golden hamsters

A 2 x 2 x 4 factorial design was used to study variation of protein and fat contents in beef broths as affected by cut type (flank, shank), salt treatments (addition of salt to the medium, no salt), and initial temperatures of simmering (25, 70, 75, and 100 degrees C). Flank portions yielded slightly more protein (0.29 g/100 mL) and had three-fold less fat (0.39 g/mL) than those of shank (0.25 and 1.12 g/mL, respectively) (P < 0.05). No linear relationship of temperature and amount of extractable components was observed, but it was clear that the greatest protein extraction was accomplished when meat was immersed in cooking water at boiling point (P < 0.05). In general, salting of water reduced fat content of beef broths. However, a significant Salting x Cut type interaction showed this effect was only present in shanks (P < 0.05). Conversely, the reducing effect (P < 0.05) of salting on amount of protein extracted from flank was not observed in shanks. Based on these data, we conclude that larger amounts of protein and less fat could be transferred from meat pieces to the medium by immersing beef in salted water at the boiling point.     

Involvement of regional lymph nodes after penetration of Schistosoma mansoni cercariae in naive and infected mice

The very low density lipoprotein receptor (VLDL-r) is a cell-surface molecule specialized for the internalization of multiple diverse ligands, including apolipoprotein E (apoE)-containing lipoprotein particles, via clathrin-coated pits. Its structure is similar to the low-density lipoprotein receptor (LDL-r), although the two have substantially different systemic distributions and regulatory pathways. The present work examines the distribution of VLDL-r in the central nervous system (CNS) and in relation to senile plaques in Alzheimer disease (AD). VLDL-r is present on resting and activated microglia, particularly those associated with senile plaques (SPs). VLDL-r immunoreactivity is also found in cortical neurons. Two exons of VLDL-r mRNA are differentially spliced in the mature receptor mRNA. One set of splice forms gives rise to receptors containing (or lacking) an extracellular O-linked glycosylation domain near the transmembrane portion of the molecule. The other set of splice forms appears to be brain-specific, and is responsible for the presence or absence of one of the cysteine-rich repeat regions in the binding region of the molecule. Ratios of the receptor variants generated from these splice forms do not differ substantially across different cortical areas or in AD. We hypothesize that VLDL-r might contribute to metabolism of apoE and apoE/A beta complexes in the brain. Further characterizations of apoE receptors in Alzheimer brain may help lay the groundwork for understanding the role of apoE in the CNS and in the pathophysiology of AD.