Hepatic regeneration after partial hepatectomy in mice infected with Schistosoma mansoni, at the acute and chronic phases of the disease. (1/56)

Outbred male albino mice normal or infected with 30 cercariae of Schistosoma mansoni (LE strain) were submitted to 65% hepatectomy during the acute (70 days) and chronic phase (160 days) phases of the disease. A group of the infected animals was treated with 400 mg/kg of oxamniquine during the acute phase before hepatectomy. Non-infected, infected and treated but not hepatectomized animals were kept as controls. Hepatic regeneration was evaluated by incorporation of tritiated thymidine, intraperitoneally injected into non-hepatectomized and hepatectomized animals, 24 hours after surgery. The results showed that removal of 65% of the hepatic parenchyma, during the acute phase, led to a statistically significant increase of thymidine incorporation, when compared with the uninfected hepatectomized controls. This phenomenon was not observed at the chronic phase. Treatment with oxamniquine administered during the acute phase led to a decrease in thymidine incorporation rate 160 days after infection (90 days after treatment) and 24 hours after hepatectomy. The data suggest that infection with S. mansoni represents a considerable stimulus for the regenerative capacity of the liver during the acute, but not the chronic phase of disease.  (+info)

Susceptibility and resistance to Schistosoma mansoni reinfection: parallel cellular and isotypic immunologic assessment. (2/56)

Cellular and humoral immune responses to Schistosoma mansoni antigen preparations were evaluated in individuals presumed to be susceptible or resistant to reinfection after chemotherapeutic cure. A consistent proliferative increase in the response to soluble egg antigen (SEA) was observed post-treatment in both the susceptible and resistant groups. However, this change was not related to resistance. Isotype studies showed that IgM antibody levels to soluble worm antigen preparation (SWAP) and cercariae antigens were significantly higher in the resistant group than in the susceptible group. Post-treatment, an increase in IgE anti-SWAP and anti-schistosomular tegument (STEG) responses and a decrease in IgG4 anti-SEA and anti-STEG responses were observed in the resistant group. These finding are similar to those we have reported previously for a putative resistant group termed endemic normals, and are compatible with immunologic studies in different endemic areas. Together, these findings indicate that even on the population level, high IgE specificities coupled with low IgG4 specificities correlate well with documented resistance to reinfection.  (+info)

Study of Schistosoma mansoni isolates from patients with failure of treatment with oxamniquine. (3/56)

After three successive treatments with oxamniquine the continuing elimination of Schistosoma mansoni eggs was observed in patients, who came from various regions of Brazil, with different clinical forms of schistosomiasis. The objective of the present study was to determine the experimental behaviour of five different S. mansoni isolates in Swiss Webster mice that were submitted to treatment with the same drug. The experimental group with failure of treatment showed higher mean number of surviving male worms when it was compared to the group without failure of treatment. These date suggest the possibility of resistance to oxamniquine.  (+info)

Evaluation of anti-Schistosoma mansoni IgG antibodies in patients with chronic schistosomiasis mansoni before and after specific treatment. (4/56)

The circumoval precipitin test (COPT), enzyme-linked immunosorbent assay (ELISA) and the immunoblotting anti-adult worm antigen (AWA) and soluble egg antigen (SEA) tests were applied to 17 chronically schistosome-infected patients for the detection of anti-Schistosoma mansoni antibodies before and on four occasions after oxamniquine administration over a period of six months. Compared to a control group, schistosomiasis patients showed high levels of IgG antibodies in AWA and SEA-ELISA. A decrease in IgG levels was observed six months after treatment, although negative reactions were not obtained. Significant decreases in IgG1, IgG3 and, mainly, IgG4, but not anti-SEA IgG2 levels were observed six months after treatment, again without negativity. Analysis of anti-AWA IgG antibodies by immunoblotting before treatment showed a 31 kDa strand in 14 patients (82%) which disappeared in three cases up to six months after treatment; furthermore, anti-SEA IgG antibodies showed the same band in nine patients (53%) before treatment, which disappeared in only four cases up to six months after treatment.  (+info)

Pathogenic aspects of pyogenic liver abscess associated with experimental schistosomiasis. (5/56)

Schistosomiasis mansoni infection that occurs concurrently with Staphylococcus aureus bacteremia favors the formation of pyogenic liver abscess. The present experimental study in mice evaluated the following aspects of the relationship between infection with Schistosoma mansoni and liver abscess caused by S. aureus: a) the role of the eggs of S. mansoni in the genesis of the abscesses; b) the influence of different phases of schistosomiasis in the development of liver abscesses; and c) the effect of the treatment of schistosomiasis on the development of the abscesses. Macroscopic and histopathological study showed multiple liver abscesses around granulomas of S. mansoni in the acute and chronic phases of schistosomiasis. Treatment of acute schistosomiasis before experimentally-induced bacteremia did not prevent the formation of liver abscess. The study findings indicate that granulomas around S. mansoni eggs and worms lodged in the liver provide a focus and substrate for pyogenic abscesses caused by S. aureus.  (+info)

Surgical hepatosplenic mansonic schistosomiasis in adolescents: repercussions of the post-treatment schistosomotic burden on the hepatic functional reserve. (6/56)

Schistosomiasis mansoni affects the hepatic functional reserve. Clinical treatment with oxamniquine is not 100% effective and there has been found strain of this parasite resistant to this drug. The aims of this investigation were: (1) to examine the presence of residual parasite burden after medical and surgical treatment on adolescents with surgical schistosomiasis mansoni and (2) to assess the effect on the hepatic functional reserve in patients with and without residual infection. Twenty nine children with hepatosplenic schistosomiasis mansoni and bleeding esophageal varices were treated with oxamniquine. They underwent splenectomy, ligature of the left gastric vein and autologous implantation of spleen tissue into the greater omentum. After a mean post-operative follow up of five years they underwent rectal biopsy for schistosomotic egg search. They were divided in patients with and without infection. In 20 patients the submucosal egg search was negative, however, in 9 it was positive. The hepatic functional reserve in the patients without infection was as follows: 17 were Child-Pugh A and 3 Child-Pugh B. In the patients who were still infected 6 were Child-Pugh A and 3 Child-Pugh B. The chi2 analysis of the hepatic functional reserve showed chi2 = 3.19 - p= 0.07. From the results the following conclusion can be drawn: residual infection or reinfection in the follow up period had not interfered with the distribution of the hepatic functional reserve of the patients in this series. However, there was a trend for a decrease of this parameter in patients with residual infection.  (+info)

Replacing oxamniquine by praziquantel against Schistosoma mansoni infection in a rural community from the sugar-cane zone of Northeast Brazil: an epidemiological follow-up. (7/56)

A group of 52 villagers was followed-up for three years regarding Schistosoma mansoni infection. All villagers were periodically surveyed by the Kato-Katz method. In March 1997 and March 1998 the positives were treated with oxamniquine (15-20 mg/kg), and in March 1999, with praziquantel (60 mg/kg). All infection indices decreased substantially between March 1999 and March 2000: prevalence of infection (from 32.7% to 21.2%), prevalence of moderate/heavy infection (from 7.7% to 1.9%), intensity of infection (from 23.1 epg to 7.4 epg) and reinfection (from 35.7% to 14.3%). Negativation increased from 53.8 to 82.4. An optimistic prognostic is assumed in the short term for the introduction of praziquantel in the study area.  (+info)

Impact of schistosomiasis on patient and graft outcome after renal transplantation: 10 years' follow-up. (8/56)

BACKGROUND: Schistosomiasis is a major health problem in some areas of the world. Schistosomal-specific nephropathy is a well-known occurrence and eventually leads to end-stage renal failure. Patients with schistosomal infection were considered to be suitable recipients for renal transplantation. However, the long-term impact of schistosomiasis on kidney transplantation is not yet been reported. METHODS: The long-term impact of schistosomiasis on patient and graft outcomes was studied by comparing two groups of subjects from a total of 243 patients. Group I consisted of cases with schistosomal infections and group II consisted of schistosoma-free controls. Schistosomiasis was documented in group I by identifying schistosoma eggs in urine, stool or rectal mucosal biopsy. Also intra-operative biopsies from bladder mucosa of the graft recipients and from the lower end of the ureter of living donors were obtained to search for schistosoma eggs. RESULTS: Sixty-three cases of schistosomiasis were diagnosed in both recipients and donors, 65 cases in recipients only, and eight cases in donors only. Infected recipients and donors with active lesions were treated at least 1 month before transplantation by combined antischistosomal drugs (praziquantel and oxamniquine). The 243 patients (136 schistosoma-infected cases and 107 controls) were followed regularly for a period of 10 years after transplantation. We found that there was no significant difference in the incidence of acute and chronic rejection between the groups; however, higher cyclosporin doses were needed for the infected group with subsequent higher incidence of both acute and chronic cyclosporin nephrotoxicity. Moreover, the schistosomal group had a significantly higher incidence of urinary tract infection and urological complications with no evidence of schistosomal re-infection. CONCLUSIONS: Despite a higher incidence of schistosoma-related complications after renal transplantation, schistosomal infection is not a major risk factor for transplantation. Therefore, infected patients can be considered as suitable recipients if they have been properly treated before transplantation.  (+info)