Study on the mechanism of miRNAs on liver injury in the condition of Protoscocephalus alveolarus transhepatic portal vein infection

OBJECTIVE

To explore the role of miRNA in liver damage caused by Echinococcus multilocularis infection.

METHODS

Six female C57BL mice were randomly divided into two groups, the control group and the infection group. Mice in the control group were injected with 100 μL PBS through the hepatic portal vein, and mice in the infection group were infected with E. multilocularis via the hepatic portal vein to establish a mouse model of infection. Small RNA sequencing was performed for detecting the expression of miRNAs in the liver of mice infected with 2000 E. multilocularis after 3 months of infection, screen out miRNAs related to liver damage, and verify by RT-PCR.

RESULTS

Seventy-one differentially expressed miRNAs were found in the liver in comparison with control, and a total of 36 mouse miRNAs with |FC| >0.585 were screened out, respectively. In addition, Targetscan (V5.0) and miRanda (v3.3a) software were used to predict differential miRNAs target genes and functional enrichment of target genes. Functional annotation showed that "cytokine-cytokine interaction," "positive regulation of cytokine production," "inflammatory response," and "leukocyte activation" were enriched in the liver of E. multilocularis-infected mice. Moreover, the pathways "human cytomegalovirus infection," "cysteine and methionine metabolism," "Notch signaling pathway," and "ferroptosis" were involved in liver disease. Furthermore, four miRNAs (mmu-miR-30e-3p, mmu-miR-203-3p, mmu-miR-125b-5p, and mmu-miR-30c-2-3p) related to liver injury were screened and verified.

CONCLUSION

This study revealed that the expression profiling of miRNAs in the livers was changed after E. multilocularis infection, and improved our understanding of the transcriptomic landscape of hepatic echinococcosis in mice.

Venous thrombosis and segmental hypoperfusion in amebic liver abscess: MDCT demonstration and its implications

PURPOSE

To report venous thrombosis and associated perfusion defect in amebic liver abscess (ALA) using MDCT.

METHOD

MDCT images of 62 patients with ALA were reviewed for venous thrombosis and associated perfusion abnormalities.

RESULT

The study found 43 (69%) patients with venous thrombosis: portal vein thrombosis (PVT) occurred in 39, hepatic vein thrombosis (HVT) in 37 and inferior vena cava (IVC) thrombosis in 4. Combined PVT and HVT occurred in 33 (77%) patients. The portal vein thrombi remained localized in subsegmental branches in 25 patients and extended to segmental branches in 14. The hepatic vein thrombi were confined to peripheral branches in 18 patients; they progressed to the main trunk in 19 and to the IVC in 4. A wedge-shaped hypoattenuating zone suggesting ischemia was identified in 33 (77%) patients in portal phase: 31 had combined PVT and HVT, 2 had HVT alone, but none had PVT alone. It occurred significantly more often with combined PVT and HVT than HVT alone (p = 0.05). Arterial phase enhancement occurred in 2 of 13 patients with multiphasic CT. All patients were symptomatic despite medical therapy and therefore required percutaneous drainage. About half of the patients were identified with ruptured abscesses. Segmental atrophy was observed in seven of nine patients who underwent follow-up CT.

CONCLUSION

Combined PVT and HVT commonly occur with ALA and often manifests as segmental hypoperfusion in portal venous phase, indicating ischemia. The detection of such events by CT may be indicative of severe disease that requires aggressive management involving percutaneous drainage.

An ultrasound-based referential of body height-adjusted normal liver organometry in school children from Bokito in rural Cameroon

The grading system for ultrasonographic assessment of Schistosoma mansoni morbidity is crucial for evaluation of control programs. This requires prior definition of normal liver organometric ranges in the population from the endemic area. A cross-sectional study was conducted in a S. mansoni endemic area in rural Cameroon. 1002 Participants were screened and 234 of them, free from all common liver-affecting diseases in the area (schistosomiasis, malaria, hepatitis B and C) and with no ultrasonographic signs of liver disease were selected and their liver parameters measured by ultrasonography. All statistics were considered significant for p-values < 0.05. Normal dimensions of livers lobe sizes, portal vein wall thickness and portal vein diameters are reported. The liver organometric data are presented for the entire study population as a whole and separately for males and females as prediction plots, with observed values and fitted regression line with 95% confidence. Reference ranges for liver parameters (size, portal vein thickness and diameter) adjusted for body height established in the current study are novel for Cameroon. The prediction plots generated should improve the accuracy of the assessment of liver morbidity by ultrasonography in the region.

Transhepatic-intrahepatic branches of the portal vein catheterization for ex vivo liver resection and autotransplantation: Two case reports of novel approach to perfuse the liver

RATIONALE

There has been increased use of ex vivo liver resection and autotransplantation (ERAT) for treatment of end-stage hepatic alveolar echinococcosis (HAE). Rapid perfusion of the autograft in bench resection is always required to reduce the warm ischemia time (WIT) and to protect the function of the remnant liver. Nevertheless, the severe invasion of the portal hepatis sometimes makes it impossible to find a usable inflow rapidly and the process of perfusion could be delayed.

PATIENT CONCERNS

Two patients diagnosed with end-stage HAE combined with severe portal hepatis invasion were selected to undergo ERAT at our center.

DIAGNOSIS

Besides the large HAE lesions, the CT imaging of patient 1 showed that part of the intra- and extrahepatic portal vein (PV) had disappeared. Patient 2 had severe invasion of both of the right and left branches of the PV.

INTERVENTIONS

We introduced a new approach for perfusing the liver in ERAT using transhepatic-intrahepatic branches of the PV catheterization. Afterward, ERAT was successfully performed.

OUTCOMES

For patient 1, the WIT was 2 minutes and the cold ischemia time (CIT) was 296 minutes. For patient 2, the WIT was 2 minutes and the CIT was 374 minutes. Patient 1 suffered stenosis of the common bile duct on postoperative day 14, and patient 2 recovered uneventfully. Both of the 2 patients were discharged from the hospital with normal laboratory values on postoperative day 31 and 15, respectively. The laboratory values for both patients at recent follow-up were normal.

LESSONS

Transhepatic-intrahepatic branches of the PV catheterization is useful for decreasing WIT and facilitating the management of ERAT. It is a useful technical variant that could be used in ERAT for treating patients with severe portal hepatis invasion.

Obliterative Endophlebitis in Mute Swans (Cygnus olor) Caused by Trichobilharzia sp. (Digenea: Schistosomatidae) Infection

Schistosome infections in mammals cause chronic proliferative vascular lesions associated with the presence of adult parasites in the lumen of mesenteric and portal veins. In birds, however, this has never been reported. In this study, we found obliterative endophlebitis associated with the presence of adult schistosomes ( Trichobilharzia sp., probably Trichobilharzia filiformis) as the main pathologic finding in five of eight mute swans ( Cygnus olor). On histologic examination, the intestinal and portal veins of these swans showed moderate to severe, diffuse, hyperplastic endophlebitis, characterized by myointimal hyperplasia, often with obliteration of the vascular lumen. In addition, moderate to severe lymphocytic and granulocytic enteritis occurred in all eight swans associated with the presence of schistosome eggs in the intestinal mucosa. Other findings included hepatic and splenic hemosiderosis and high hepatic copper levels. The vascular lesions associated with Trichobilharzia sp. infection may have contributed to the emaciation and death of those mute swans by obstruction of venous return in the intestinal and portal veins.

Towards the establishment of a porcine model to study human amebiasis

BACKGROUND

Entamoeba histolytica is an important parasite of the human intestine. Its life cycle is monoxenous with two stages: (i) the trophozoite, growing in the intestine and (ii) the cyst corresponding to the dissemination stage. The trophozoite in the intestine can live as a commensal leading to asymptomatic infection or as a tissue invasive form producing mucosal ulcers and liver abscesses. There is no animal model mimicking the whole disease cycle. Most of the biological information on E. histolytica has been obtained from trophozoite adapted to axenic culture. The reproduction of intestinal amebiasis in an animal model is difficult while for liver amebiasis there are well-described rodent models. During this study, we worked on the assessment of pigs as a new potential model to study amebiasis.

METHODOLOGY/PRINCIPAL FINDINGS

We first co-cultured trophozoites of E. histolytica with porcine colonic fragments and observed a disruption of the mucosal architecture. Then, we showed that outbred pigs can be used to reproduce some lesions associated with human amebiasis. A detailed analysis was performed using a washed closed-jejunal loops model. In loops inoculated with virulent amebas a severe acute ulcerative jejunitis was observed with large hemorrhagic lesions 14 days post-inoculation associated with the presence of the trophozoites in the depth of the mucosa in two out four animals. Furthermore, typical large sized hepatic abscesses were observed in the liver of one animal 7 days post-injection in the portal vein and the liver parenchyma.

CONCLUSIONS

The pig model could help with simultaneously studying intestinal and extraintestinal lesion development.

Expression, characterization and therapeutic efficacy of chimeric Fab of anti-idiotypic antibody NP30 against Schistosoma japonicum

The murine monoclonal anti-idiotypic antibody NP30 is a promising therapeutic antibody against Schistosoma japonicum. However, the immunogenicity of murine NP30 limits its further study and application in humans. Here the chimeric Fab of NP30 (chFab-NP30) comprising the variable regions of murine NP30 and constant regions of human antibody was assembled. chFab-NP30 was expressed and purified as a soluble and functional protein. Administration of chFab-NP30 in vivo increased the survival rate, reduced egg burdens and ameliorated organ pathology of mice with acute schistosomiasis. Our study indicated that chFab-NP30 is a promising candidate to be used as a specific and efficient recombinant antibody against acute schistosomiasis japonica. Further studies on function mechanism of chFab-NP30 needs to be carried out in the future.

Endoscopic variceal sclerotherapy in patients with Symmers periportal fibroses

This is a prospective study, carried out in patients with portal hypertension and bleeding oesophageal varices secondary to Symmers (Schistosomal) periportal fibroses, to determine the efficacy of sclerotherapy, the number of sessions needed to achieve full sclerosis, the complications associated with sclerotherapy and the incidence and risk factors for rebleeding. In total, 85 patients were studied with a mean age of 38 years, 76.5% were males. All underwent upper gastrointestinal endoscopy, had different grades of oesophageal varices and underwent intravariceal injection with 5% ethanolamine oleate until they achieved full sclerosis or were referred to surgery. Complications of sclerotherapy included oesophageal strictures, deep oesophageal ulcers, pleural effusion and ascites. Following obliteration of oesophageal varices, 3.5% and 20% developed new gastric varices and portal gastropathy, respectively. Rebleeding occurred in 32% - the only significant predictive risk factor for which was patients with GIII varices following the first sclerotherapy session. Varices recurred in 6% of patients after a mean follow-up period of one year. In total, 93% of our patients achieved full sclerosis after an average of four sessions, and 3.5% were referred for surgery. Three patients (3.5%) died, all from massive rebleeding. In conclusion, sclerotherapy is a safe effective method for treating patients with oesophageal varices due to periportal fibroses.

Nomadic or sessile: can Kupffer cells function as portals for malaria sporozoites to the liver?

The initial site of replication for Plasmodium parasites in mammalian hosts are hepatocytes, cells that offer unique advantages for the extensive parasite replication occurring prior to the erythrocytic phase of the life cycle. The liver is the metabolic centre of the body and has an unusual relationship to the immune system. However, to reach hepatocytes, sporozoites must cross the sinusoidal barrier, composed of specialized endothelia and Kupffer cells, the resident macrophages of the liver. Mounting evidence suggests that, instead of taking what would seem a safer route through endothelia, the parasites traverse Kupffer cells yet suffer no harm. Kupffer cells have a broad range of responses towards incoming microorganisms, toxins and antigens which depend on the nature of the intruder, the experimental conditions and the environmental circumstances. Kupffer cells may become activated or remain anergic, produce pro- or anti-inflammatory mediators. Consequently, outcomes are diverse and include development of immunity or tolerance, parenchymal necrosis or regeneration, chronic cirrhotic transformation or acute liver failure. Here we review data concerning the unique structural and functional characteristics of Kupffer cells and their interactions with Plasmodium sporozoites in the context of a model in which these hepatic macrophages function as the sporozoite gate to the liver.

Disagreement between ultrasound and magnetic resonance imaging in the identification of schistosomal periportal fibrosis

Abdominal ultrasound (US) has been widely used in the evaluation of patients with schistosomiasis mansoni. It represents an important indirect method of diagnosis and classification of the disease, and it has also been used as a tool in the evaluation of therapeutic response and regression of fibrosis. We describe the case of a man in whom US showed solid evidence of schistosomal periportal fibrosis and magnetic resonance imaging revealed that periportal signal alteration corresponded to adipose tissue which entered the liver together with the portal vein.

[Identification of the SjARG novel gene and study on its protective potential as a vaccine]

OBJECTIVE

To recognize and identify the arginase (ARG) gene of Schistosoma japonicum(Sj), and to study its protection potential as a vaccine.

METHODS

The 5'-end of the ARG gene from the Sj cercariae cDNA library was amplified by nested-PCR and the sequence was identified by bioinformatics. The complete coding sequence(CDS) was cloned into pET30a (+) vector, and a recombinant SjARG protein (rSjARG) was expressed, purified and used to raise antibodies. ARG's activity as an enzyme was tested by ornithine-ninhydrin reaction. Western blotting was used to compare the immunologic characteristics of rSjARG with that of the native one in Sj adult worm. Indirect immunofluorescence assay was used to immunolocalize it. For evaluating the protection potential of rSjARG, mice were immunized by the recombinant protein and challenged by cercariae of S japonicum.

RESULTS

The CDS length of the SjARG novel gene was identified as 1095bp rSjARG showed enzyme activity and the same immunologic characteristics with the native arginase in adult worm. SjARG located in the genital organ and gut of both sexes. The worm reduction rate and egg reduction rate in rSjARG group were 55.8% and 48.8% respectively, higher than that of the rSj26GST group (28.6% and 6.89% respectively).

CONCLUSION

SjARG gene was identified, which shows a higher protection than the Sj26GST.

EUS diagnosis of vascular invasion in pancreatic cancer: surgical and histologic correlates

BACKGROUND

Endoscopic ultrasound (EUS) has been compared to intraoperative surgical palpation for diagnosis of vascular invasion by pancreatic cancer. This study compares EUS with vascular resection and histologic evidence of vascular invasion in resected pancreatic masses.

METHODS

All patients with solid pancreatic masses who underwent both preoperative EUS and surgery at 1 hospital over a 7 year period were identified. The relationship of pancreatic masses to adjacent vessels was prospectively assessed by EUS. EUS findings were compared to surgical and pathology gold standards. "Vascular adherence" was defined as tumor adherence requiring vascular resection during surgery, and "vascular invasion" as histologic invasion of vessel wall by tumor.

RESULTS

30 of 68 patients were resectable. Among these 30, vascular adherence was present in 8, including 18% of patients with an intact echoplane between tumor and adjacent vessels at EUS, 29% of those with loss of echoplane alone, and 50% of those with additional EUS features of vascular involvement. Vascular invasion was present in 4, including 12% of patients with an intact echoplane, 0% of those with loss of echoplane alone, and 33% of those with additional EUS features. Sensitivity, specificity, PPV, and NPV of EUS were 63%, 64%, 43% and 80% for vascular adherence and 50% 58%, 28% and 82% for vascular invasion. NPV rose to 90% for vascular adherence if only the portal confluence vessels were considered.

CONCLUSIONS

EUS has poor sensitivity, specificity, and positive predictive value for diagnosis of venous involvement by pancreatic cancer.

Comparative clinical and ultrasound study of egg-negative and egg-positive individuals from Schistosoma mansoni low morbidity endemic areas, and hospitalized patients with hepatosplenic disease

Two hundred and twenty three subjects from a Schistosoma mansoni low morbidity endemic area and nine hospitalized hepatosplenic patients were submitted to stool test and clinical examination and abdomen ultrasound assessments. According to stool examination and ultrasound results, they were grouped as follows: G1 -- 63 Schistosoma mansoni egg-negative individuals; G2 -- 141 egg-positive patients and without evidence of periportal fibrosis; G3 -- 19 egg-positive patients with periportal echogenicity (3-6 mm); and G4 -- 9 hepatosplenic patients with periportal echogenicity (> 6 mm). Hepatomegaly detected by physical examination of the abdomen evaluated in the midclavicular line was verified in G1, G2 and G3, respectively, in 11.1, 12.1 and 26.3%. In G1, G2 and G3, periportal thickening occurred only in schistosomal patients (8.5%). Mild pathological alterations in patients that cannot yet be detected by clinical examination were detectable in the liver by ultrasound and can be due to fibrosis. The degree of mild periportal fibrosis was diminished in 57.9% of patients 12 months after treatment of schistosomiasis with oxamniquine. At ultrasonography, the mean liver left lobe measurement of G3 was larger than that of G1, and that of G4 larger than that of G1 and G2. The mean size of the spleen of G4 was significantly larger than that of the other three groups, and that of G3 larger than that of G1 and G2.

Ultrasound organometry: the importance of body height adjusted normal ranges in assessing liver and spleen parameters among Chinese subjects with Schistosoma japonicum infection

Hepatosplenic measurements among 550 Chinese subjects, aged 3-59 years from Yueyang city--a nonendemic area for schistosomiasis in Hunan province, China--were performed to define normal ranges of ultrasound organometry for assessing hepatosplenic morbidity in Schistosoma japonicum infection. Measurements included the size of the liver (left lobe and right lobe), the main portal vein stem, the peripheral periportal vein branches, and spleen length and thickness. The results document the significant relationship between body height and organometric parameters. The reference values stratified by body height improve the accuracy of assessment. Thus, height-based normal ranges established in this study can be applied in hospital routine and in field studies of patients infected with S. japonicum in Hunan province and in other endemic areas of China.

Treatment with mebendazole is not associated with distal migration of adult Angiostrongylus costaricensis in the murine experimental infection

Abdominal angiostrongyliasis is a zoonotic infection produced by a metastrongylid intra-arterial nematode, Angiostrongylus costaricensis. Human accidental infection may result in abdominal lesions and treatment with anti-helminthics is contra-indicated because of potential higher morbidity with excitement or death of worms inside vessels. To evaluate the effect of mebendazole on localization of the worms, male Swiss mice, 5 week-old, were infected with 10 third stage larvae per animal. Twelve infected mice were treated with oral mebendazol, at 5 mg/kg/day, for 5 consecutive days, begining 22 days after inoculation. As control groups, 12 infected but non-treated mice and other 12 non-infected and non-treated mice were studied. The findings at necropsy were, respectively for the treated (T) and control (C) groups: 92% and 80% of the worms were inside the cecal mesenteric arterial branch; 8% and 10% were located inside the aorta. Only in the group C some worms (10%) were found inside the portal vein or splenic artery. These data indicate that treatment with mebendazole does not lead to distal or ectopic migration of A. costaricensis worms.

Epidemiological and morbidity assessment of Schistosoma japonicum infection in a migrant fisherman community, the Dongting Lake region, China

We assessed the epidemiology and morbidity related to Schistosoma japonicum infection by both parasitological (Kato-Katz method and miracidium hatching test) and ultrasound examination in a migrant fisherman community (n = 106) from the Dongting Lake region in China in 2001. A prevalence of 69.8% and a mean infection intensity of 66.5 eggs per gram (epg) were recorded for this group. Males had a higher level of infection (77%) and intensity (92.2 epg) compared with females (58% and 28.6 epg, respectively). Subjects aged 11-20 years had the highest prevalence of infection (91%) and the heaviest infection intensity (85.3 epg) among all age groups. Twenty-six percent of the subjects had not been treated previously for schistosomiasis. Parenchymal fibrosis (> or = stage II) detected by ultrasound and spleen enlargement (or splenectomy) occurred in 37% and 9% of subjects, respectively. Portal vein dilation was detected in 18% subjects, and 58% (11/19) of those patients with portal vein enlargement were shown to have parenchymal fibrosis (> or = stage II). These results indicate that S. japonicum infection and related morbidity in mobile fisherman is still unacceptably high despite the fact that China has implemented a Schistosomiasis Control Project financed by a World Bank Loan for a period of 8 years since 1992. Clearly, new approaches for schistosomiasis control, especially in communities like these mobile fishermen, should be explored.

Vaccination of domestic pig with recombinant paramyosin. against Schistosoma japonicum in China

Paramyosin (PM), a myosin-like protein is a major antigen on Schistosoma japonicum (Sj). We reported that passive transfer of a monoclonal IgE SjE18varepsilon.1 which recognizes PM of Sj (SJPM), partially protected mice from challenge infection. In the present study, we developed an experimental model system of schistosomiasis japonica with domestic pigs in China and used it for the evaluation of vaccination with recombinant SJPM (rSJPM). Sixteen-week-old pigs were successfully infected by dermal penetration of 120 cercariae of a domestic strain of Sj (50-60% worm recovery 11 weeks after challenge). The pigs vaccinated with 400 UV attenuated cercariae showed a reduction of worm recovery (53%, p<0.001). The experimental groups were immunized intradermally with rSJPM and alum or TiterMax and were partially protected against the challenge infection (32-35% reduction).

Human portal serum stimulates cell proliferation in immature Schistosoma mansoni

Schistosomula of Schistosoma mansoni were incubated in RPMI 1640 medium containing 10% fetal calf serum, 10% human portal venous or 10% human peripheral venous sera in the presence of bromodeoxyuridine (BrdU) in order to measure differences in cell proliferation. The rates of cell proliferation as expressed by BrdU labelling indices (BLI) were determined as a function of time of incubation by immunohistochemistry using monoclonal antibody to BrdU. Compared to schistosomula cultured in the presence of RPMI plus 10% fetal calf serum, BLIs were increased by 60% in the presence of human portal, but not in peripheral serum. This stimulatory effect was substantially reproduced by a fraction of portal serum with a molecular weight range between 1 and 50 kDa. However, in the presence of human peripheral venous serum, either whole or fractionated, schistosomula showed no significant difference compared to RPMI plus 10% fetal calf serum alone. Furthermore, human portal serum fractions of molecular weight greater than 50 kDa also revealed no significant difference relative to control. The results indicate that portal venous serum component(s) of a molecular weight range higher than most simple nutrients can greatly stimulate the rate of cell proliferation of Schistosoma mansoni schistosomula.

Characterization of kinetics of anti-Trichinella spiralis newborn larvae immunity in rats

The kinetics of anti-T. spiralis newborn larvae (NBL) immunity and its dose effects were studied in vivo. Rats were either immunized with newborn larvae i.v. or muscle larvae per os and challenged with newborn larvae either i.v. or i.p. on day 7 up to day 27 after immunization. Immunity was assessed by examining the muscle larvae burden or the larval recovery from the peritoneal cavity. Recovered newborn larvae were further examined for cell adherence and viability. Results indicate that as early as 9 days after infection and only 3 days after newborn larvae production in vivo, specific anti-newborn larvae immunity was developed. Peritoneal cells as well as blood cells adhered to the cuticles of the larvae and killed them. When different doses of immunization were examined, it was found that 2,000 muscle larvae per os induced the strongest immunity as compared to 500, 5,000 or 6,000. Such immunity maintained its strength when challenge infection with newborn larvae reached 50,000 dosage and it declined significantly when the dose reached 100,000. This indicates that the immune cells and antibodies are not re-deployed.

Schistosome-induced portacaval haemodynamic changes in Rattus rattus are associated with translocation of adult worms to the lungs

The presence of naturally portacaval shunts has been investigated in the vasculature of normal and Schistosoma mansoni-infected Rattus rattus. Using the technique of injecting Polystyrene microspheres in the superior mesenteric vein, we demonstrated that the presence of adult schistosomes in the lungs of R. rattus was not due to an innate anomaly of the rat vasculature but resulted from the formation of portacaval shunts during infection. In rats harbouring a bisexual infection, microspheres were only detected in the lungs from week 7. The development and increasing size of the shunts were maximal between weeks 7 and 10 and coincident with the translocation of adult worms from the portal tract to the lungs. At weeks 20-25, only 1-2% of the microspheres were recovered from the lungs, suggesting that the portacaval anastomoses have regressed due to reduction in portal hypertension after worm translocation. R. rattus with a male-only schistosome infection harboured adult worms in the lungs, indicating that the development of shunts does not solely depend upon egg deposition in the liver to generate hypertension. The relationships between the presence of the schistosomes in the lungs, the portacaval shunting and the resistance to reinfection is discussed.

Evaluation of ultrasonographic staging systems for the assessment of Schistosoma mansoni induced hepatic involvement

For the sonographic assessment and grading of hepatosplenic morbidity induced by Schistosoma mansoni infection, several quantitative and qualitative classification systems have been used. In an attempt to evaluate two staging systems, a study was performed as part of a schistosomiasis research and control programme in Richard Toll, Senegal. A total of 700 residents of the township N'diangué were parasitologically, clinically and sonographically examined in July 1993. Two ultrasound observers (M.D. and E.D.) applied the Cairo and the Managil classification (E.D. only) for the grading of periportal thickening of the liver. In spite of high prevalence and intensity of infection, severe hepatic morbidity was rare. According to the Cairo classification, there was a high percentage of subjects with grade I periportal thickening, with considerable inter-observer variability. In the Cairo classification, which is based on the diameter of peripheral portal vein branches, firm cut-offs are used, independent of body height. We show the relationship between body height and portal vein diameters and recommend the use of body height-dependent reference values to avoid falsely high percentages of periportal thickening, especially in children. To minimize inter-observer variability, a clarification of existing instructions for taking measurements for grading is suggested. These suggestions have been considered during the follow-up expert meeting on the Cairo classification in Niamey under the auspices of the World Health Organization in October 1996.

Study of the efficacy of the new antischistosomal drug 10-[2-(diethylamino)ethyl]-9-acridanone-(thiazolidin-2-ylidene) hydrazone against an Egyptian strain of S. mansoni in mice

The efficacy of 3 doses (10, 15 and 20 mg/kg) of the new antischistosomal drug Ro 15-5458 (10-[2-(diethylamino)ethyl]-9-acridanone-(thiazolidin-2-ylidene)hy drazone, CAS 092928-47-7) against an Egyptian strain of S. mansoni was studied in mice. The effect of duration of infection on the response of mice to treatment with 20 mg/kg was evaluated at 7 and 12 weeks after infection. The criteria used for the assessment of drug efficacy were: worn count and distribution in the liver and portomesenteric system, oogram changes in the small intestine, estimation of the number of ova/g stood, liver and intestine and histopathological examination of mice liver. Data revealed a dose dependent decrease in number of adult worms and number of ova/g stool, liver and intestine. A reduction of 83.6, 89.4 and 94.9% in mean number of schistosomes compared to control was recorded following treatment with 10, 15 and 20 mg/ kg of the drug, respectively. Oogram changes were more remarkable following treatment with 20 mg/kg as evidenced by complete disappearance of all immature stages. Treatment with Ro 15-5458 in a dose of 20 mg/kg resulted in complete disappearance of couples and 100% shift or worms to the live. Examination of mice liver 2 weeks post treatment revealed on changes in pathology following treatment with 10 mg/kg compared to control. Treatment with 20 mg/kg gave better results comparable to 15 mg/kg, a decreased number and size of granulomas with minimal areas of necrosis was observed. Parasitological cure was effectively achieved when treatment was initiated 7 or 12 weeks post infection. However, histopathological data revealed that the earlier the treatment the better the results.

Recovery of Schistosoma japonicum from experimentally infected pigs by perfusion of liver and mesenteric veins

An optimized procedure for perfusion of pigs infected with Schistosoma japonicum was developed. The technique involves insertion of a perfusion influx tube into the thoracic descending aorta, clamping vessels to parts of the body which did not need to be perfused (the kidneys, hind legs, etc.) and placing a collection tube directly into the portal vein. In addition, the clamping technique allows for separate perfusion of the liver and intestinal veins. The perfusion medium was a sodium citrate buffer (40 degrees C) to which the vasodilator sodium nitroprusside was added. Furthermore, an experiment was conducted to investigate if the perfusion efficiency, measured by total worm recovery, could be increased if praziquantel was administered prior to perfusion. Twelve pigs were each infected with 1000 S. japonicum cercariae and their schistosomes were collected 11 weeks later by separate perfusion of the liver and intestinal veins. Six of these pigs were treated orally with praziquantel one hour before perfusion. In general, the vessels of the livers and intestines of all pigs were well perfused, judging by the resulting pale colour of the tissues. Worms from praziquantel treated pigs were collected within 5 min of perfusion as opposed to approximately 20 min in the non-treated pigs. More worms were collected from the livers of the praziquantel treated pigs, indicating a hepatic shift of schistosomes from the intestinal mesenteries. However, comparable numbers of worms were retained in the mesenteric veins following perfusion in the 2 groups, indicating that manual recovery of schistosomes from the intestinal mesenteries is necessary in addition to perfusion for obtaining the total worm counts. Another experiment was conducted to determine if the intensity and/or duration of infection had an effect on the number of worms collected by the perfusion technique. Seventy-two pigs were allocated into 3 groups of 24 pigs each, which were infected with either 100, 500 or 2000 cercariae per pig. The 3 groups were further divided into 4 subgroups of 6 pigs each which were perfused with our selective technique at 4, 11, 17 or 24 weeks post infection, respectively. All of the pigs received an oral praziquantel treatment prior to perfusion. The results indicated that increasing intensities and/or duration of infection resulted in trapping of schistosomes in intravascular inflammatory reactions which made it more difficult to collect the adult schistosomes by perfusion.

Elaeophorosis in red deer caused by Elaeophora elaphi: lesions of natural disease

This is the first study of the lesions produced by Elaeophora elaphi, a filarial worm first reported in 1986. Only the morphologic characteristics of this species have been described previously. Samples for the study were taken from 74 red deer (Cervus elaphus), 1-10 years old, slaughtered in central Spain. Grossly, filariae were observed in the transverse, left, or right branches of the portal vein of 18 animals. In addition to filariae, whitish thrombi were found in the right and left branches of the portal vein in nine animals. Thrombi of similar characteristics were also observed in 12 deer in which no adult filariae were found. Microscopic changes were observed only in the right and left branches of the portal vein and consisted of thickening of the intima with surface formation of villi. Stroma of villi contained a moderate to intense infiltrate composed mainly of eosinophils and mononuclear cells. The tunica media of affected vessels was uniformly hypertrophic and in some cases presented a moderate inflammatory infiltrate similar to that observed in the stroma of villi. Thrombi consisted of a central area containing calcified filariae or cuticle debris, surrounded by giant cells and numerous lymphoid cells forming clearly defined nodules resembling lymphoid follicles. Thrombi were externally surrounded by a strip of connective tissue and beyond by endothelial cells that were occasionally continuous with the tunica intima. Other lesions probably associated with the infestation were multifocal granulomas in the periportal areas, lymphoid tissue formations in the hepatic parenchyma, and an interstitial nephritis.

Comparative study on the localization of adult Schistosoma mansoni worms in albino mice anesthetized with pentobarbital sodium, ether or chloroform

The effect of anesthetic drugs on the localization of adult worms in albino mice was compared. The animals with 56 days of infection were anesthetized with pentobarbital sodium, ether or chloroform. Perfusion was carried out immediately after, recovering the worms and classifying them in relation to their localization on the liver or portal vein and the mesenteric veins. Our results showed that pentobarbital sodium produced a greater displacement of the worms to the liver (89%) than ether (76%) and chloroform (34%) did, when compared to the control group (22%). The difference between pentobarbital sodium and ether was significant (p < 0.05). We suggest that anesthetic drugs may not be used in studies on the distribution of adult worms in several hosts.

Asexually proliferous tetrathyridia of Mesocestoides sp. in the hepatic portal system of the prairie rattlesnake (Crotalus viridis viridis)

A female prairie rattlesnake (Crotalus viridis viridis) was gastric intubated with 250 tetrathyridia of Mesocestoides sp. The snake was killed 12 wk postinfection; a portion of the liver was examined histologically for evidence of tetrathyridia. Five tetrathyridia were seen in two hepatic portal triad vessels. We propose that a blood-borne metastasis of tetrathyridia in reptiles and rodents may occur.

Schistosoma mansoni: mechanism of attrition and routes of migration from lungs to hepatic portal system in the laboratory mouse

The number of schistosomula in the axillary lymph nodes of mice was determined by compressed tissue autoradiography at 13 intervals from 0.5 to 28 days after exposure of abdominal skin to 75Se-labeled cercariae of S. mansoni. Significant accumulations were observed between days 3 and 6 and peaked on day 4 at which time 9.4 +/- 1.1% of the schistosomula present in the whole body were found in the axillary lymph nodes. The total number and distribution of schistosomula in all tissues of mice were likewise determined at 12 intervals from 3 to 24 days following exposure. The frequent appearance of small numbers of schistosomula in trachea and esophagus suggested that normal attrition resulted at least in part from physical expulsion of schistosomula from the body by way of the tracheobronchial tree and gastrointestinal tract. The distribution of schistosomula observed in heart chambers, caudal vena cava, hepatic portal vein, aorta, intestinal wall, thoracic cavity rinses, and diaphragm supported all 3 standing hypotheses regarding route of migration from lungs to hepatic portal system, i.e., that schistosomula migrate via (1) the pulmonary artery, right heart, caudal vena cava, and hepatic veins, (2) the pulmonary vein, left heart, aorta, and cranial mesenteric artery, and (3) the thoracic cavity and diaphragm.

Trichinella spiralis: intestinal expression of systemic stage-specific immunity to newborn larvae

Rats immunized with newborn Trichinella spiralis larvae i.v. were found to confer a specific anti-newborn larvae immunity in the small intestine. In rats immunized with newborn larvae i.v. and then challenged with adult worms intraintestinally, total newborn larvae recovery was reduced by 75-90% in thoracic duct lymph and in hepatic portal vein blood. No newborn larvae were found in the peritoneal fluid of immunized rats. In addition to an absolute reduction in number, larval migration from the small intestine to the thoracic duct was delayed by 6-12 h and migration to the portal vein was inhibited for at least 8 h. The establishment of adult worms in the small intestine and female worm fecundity were not affected by anti-newborn larvae immunity. Identical quantitative effects on newborn larvae migration from the small intestine were achieved by homologous transfer of anti-newborn larvae immune serum i.v. into naive recipient rats.

Schistosoma mansoni: effects of anesthetics and antimonial drugs on worm shift in the mouse

Mice experimentally infected with Schistosoma mansoni were injected with sodium thiopental or sodium antimonyl gluconate (Triostib R), or submitted to halothane inhalation, with or without a previous injection of thiopental. Data obtained showed that halothane and thiopental induce worm shift to the liver (99 and 76%, respectively). Sodium gluconate and antimonium (Triostib R) shifted 52% of worms towards the liver. These results seem to indicate that the use of antimonium would be unnecessary, when surgical removal of schistosomules is carried out through the extracorporeal filtration technique, in patients with portal hypertension.

Ultrasonographic diagnosis of schistosomal periportal fibrosis

Hepatosplenic schistosomiasis results from infestation by Schistosoma mansoni, a blood fluke. Presinusoidal periportal fibrosis is invariably the result of this infestation. The ultrasonic pattern of schistosomal periportal fibrosis in 22 patients in whom schistosomal hepatic involvement was proven histologically is described. Echogenic areas of pipestem fibrosis seen as tubular shadows, some containing central lucencies, were present in every case. These tubular shadows conformed to the structure of the portal veins, producing a characteristic appearance. In endemic areas this appearance may be the only clue to the diagnosis of hepatosplenic schistosomiasis, because patients may remain asymptomatic for years after the onset of the disease.

[Localization of Schistosoma mansoni in the portal plexus of Mus musculus infected experimentally by a single sex of trematode]

Foi estudado o hábito migratório de Schistosoma mansoni em infecções bissexuais e nas produzidas por um só sexo do trematódeo, tendo sido evidenciada a influência do sexo no deslocamento dos esquistossomos. Nas infecções bissexuais parece que o deslocamento dos vermes para os vasos mesentéricos visa o acasalamento e a oviposição.

Durikainema macropi gen. et sp. nov. (Muspiceoidea: Robertdollfusidae). A remarkable nematode from Macropodidae (Marsupialia)

Durikainema macropi gen. et sp. nov. (Muspiceoidea: Robertdollfusidae) is described from the mesenteric and hepatic portal veins of Macropus giganteus Shaw 1790, M. agilis (Gould 1842) and M. rufogriseus (Desmarest 1817) (Marsupialia: Macropodidae) from Queensland, Australia. It is also known from histological sections of hepatic portal veins of M. robustus Gould 1841, M. fuliginosus (Desmarest 1817) and Lagorchestes conspicillatus Gould 1842. The new genus resembles the Enoplina in cephalic and caudal characters and the Dorylaimina in other characters. Durikainema resembles Robertdollfusa Chabaud and Campana 1950 in its small form, absence of mouth oesophagus and anus, atrophied digestive tube, reduction of female genital apparatus to a uterine pouch, viviparity and cephalic cuticular inflation in larvae. It differs from this genus in its complex and well developed cephalic structures and its well developed body musculature in both sexes. Durikainema is tentatively placed in the Robertdollfusidae, Muspiceoidea. Larvae develop beyond firststage in the uterus of the female. They have been found in the non-peripheral blood of male and female M. giganteus, the lactating mammary gland of female M. agilis but not the non-lactating glands of the same female and in the deep capillaries of thigh skin of male M. agilis. Transmission of the parasite may be direct by a percutaneous or milk route, or indirect by a haemophagous arthropod.

Resistance induced by normal and irradiated Schistosoma mansoni: ability of various worm stages to serve as inducers and targets in mice

Lung stage schistosomula exposed to 50 kilorads of gamma irradiation induced significant resistance to challenge infection with Schistosoma mansoni following intravenous (tail or mesenteric vein), intramuscular, or intraperitoneal injection into mice. Similar or higher levels were induced with irradiated cercariae, while irradiated 3- or 4-week-old worms induced little resistance. Non-irradiated day 6 and day 12 lung schistosomula injected into mice immunized with irradiated cercariae were susceptible to elimination, though to a lesser extent than a challenge infection administered at the cercarial stage. Day 20 liver worms injected into a mesenteric vein were not susceptible to irradiated cercaria-induced resistance. In contrast, cercariae, day 6 lung schistosomula, day 12 lung schistosomula and day 20 liver worms were all susceptible to the resistance induced by a chronic (non-irradiated) infection.

Attrition of schistosomes in an irradiation-attenuated cercarial immunization model of Schistosoma mansoni

The attrition of Schistosoma mansoni challenge worms was studied in irradiation-attenuated cercaria-immunized mice as a function of site and time. The peak recovery of schistosomula from the lungs of immunized mice was delayed 2 days in comparison with non-immunized controls. The difference between the peak recoveries of control and immunized mice accounted for about half of the final attrition observed at the 7-week adult worm stge. Hepatic-mesenteric vein worm recoveries obtained 10 to 42 days after challenge were reduced in most cases at least as much as the 49-day counts. Somewhat higher reductions were observed at 14 to 28 days than at 49 days, confirming the evidence of delayed migration obtained at the lung phase. These findings, coupled with histologic observations, indicate that at least half of the worm elimination attributable to immunization occurs 8 or more days after the challenge infection.

The pathology of naturally-occurring bovine schistosomiasis in the Sudan

The gross and histopathological lesions of naturally-occurring bovine schistosomiasis in the Sudan are detailed. Out of 61 animals examined, 53 were found infected with Schistosoma bovis, showing lesions in their livers, intestinal tracts and other organs. Apart from granulomas, periportal inflammatory infiltration, fibrosis and pigmentation of Kupffer cells, livers of infected cattle revealed peculiar lesions in the form of "nodular sclerosis", medial hypertrophy of portal veins and lymphoid nodule and follicle formation around parasites. In the intestines, variable manifestations of catarrh, with eosinophilic infiltration, granulomatous reaction and vascular changes, were observed. Pancreatic schistosomiasis was common and some animals had lesions in their lungs and lymph nodes. Urogenital lesions, rectal and colonic polyps, congestive splenomegaly, gastro-oesophageal variaces and Symmer's clay-pipe stem fibrosis of the liver were not seen in cattle. The haematological and serum protein findings in infected animals were included. The findings were related to the lesions observed and the need for detailed study of functional disturbances in bovine schistosomiasis is indicated.