Cutaneuos cryoglobulinemic vasculitis induced by chronic hepatitis C virus infection

Cutaneous vasculitis may represent a great clinical challenge, even after careful dermatological examination and laboratory assessment. The authors present a case of cutaneous cryoglobulinemic vasculitis associated to chronic hepatitis C virus infection, pointing out the importance of the dermatological examination for diagnostic investigation. They discuss about the importance of defining the etiology and making correct classification for appropriate prognosis and treatment of cutaneous vasculitis.

Liver HLA-G expression is associated with multiple clinical and histopathological forms of chronic hepatitis B virus infection

As the mechanisms leading to the persistence of hepatitis B virus (HBV) infection are poorly understood and as the histocompatibility leucocyte antigen (HLA)-G is well described as a tolerogenic molecule, we evaluated HLA-G expression in 74 specimens of HBV liver biopsies and in 10 specimens obtained from previously healthy cadaver liver donors. HBV specimens were reviewed and classified by the METAVIR score, and HLA-G expression was assessed by immunohistochemistry. No HLA-G expression was observed in control hepatocytes. In contrast, 57 (77%) of 74 HBV specimens showed soluble and membrane-bound HLA-G expression in hepatocytes, biliary epithelial cells or both. No associations between the intensity of HLA-G expression and patient age or gender, HBeAg status, severity of liver fibrosis, and grade of histological findings were observed. Although significance was not reached (P = 0.180), patients exhibiting HLA-G expression presented a higher median HBV DNA viral load (105 copies/mL) than those who did not express HLA-G (103.7 copies/mL). These results indicate that HLA-G is expressed in most cases of chronic HBV infection in all stages and may play a role in the persistency of HBV infection.

Increased activities of cardiac matrix metalloproteinases matrix metalloproteinase (MMP)-2 and MMP-9 are associated with mortality during the acute phase of experimental Trypanosoma cruzi infection

The strong inflammatory reaction that occurs in the heart during the acute phase of Trypanosoma cruzi infection is modulated by cytokines and chemokines produced by leukocytes and cardiomyocytes. Matrix metalloproteinases (MMPs) have recently emerged as modulators of cardiovascular inflammation. In the present study we investigated the role of MMP-2 and MMP-9 in T. cruzi-induced myocarditis, by use of immunohistochemical analysis, gelatin zymography, enzyme-linked immunosorbent assay, and real-time polymerase chain reaction to analyze the cardiac tissues of T. cruzi-infected C57BL/6 mice. Increased transcripts levels, immunoreactivity, and enzymatic activity for MMP-2 and MMP-9 were observed by day 14 after infection. Mice treated with an MMP inhibitor showed significantly decreased heart inflammation, delayed peak in parasitemia, and improved survival rates, compared with the control group. Reduced levels of cardiac tumor necrosis factor-alpha, interferon-gamma, serum nitrite, and serum nitrate were also observed in the treated group. These results suggest an important role for MMPs in the induction of T. cruzi-induced acute myocarditis.

Effects of non-specific immunopotentiators in experimental Schistosoma mansoni infection: II. Corynebacterium parvum

The effects of Corynebacterium parvum on host protection, tissue reaction and "in vivo" chemotaxis in Schistosoma mansoni infected mice were studied. The C. parvum was given intraperitoneally using a dose of 0.7 mg, twice a week (for 4 weeks), thirty days before (prophylactic treatment) or after infection (curative treatment). The host protection was evaluated through the recovery of adult worms by liver perfusion and was lower in the prophylactic group as compared to the control group (p = 0.018), resulting in 44% protection. The "in vivo" leukocyte response in both prophylactic and curative groups was higher as compared to the infected/non treated group (p = 0.009 and p = 0.003, respectively). Tissue reactions were described in the experimental and control groups, but there were not remarkable differences among them. The possible biological implications and relevance of the findings for the defensive response of the host and control of schistosomiasis are discussed.

PARASITOLOGICAL AND MOLECULAR DIAGNOSIS IN EXPERIMENTAL Strongyloides venezuelensis INFECTION

Strongyloides venezuelensis is a parasitic nematode of rats which is frequently used as a model to study human and animal strongyloidiasis. The aim of this study was to evaluate the correlation between parasitological and molecular diagnosis in Strongyloides venezuelensis infection. PCR assays were used to detect S. venezuelensis DNA in fecal samples obtained from experimentally infected Rattus norvegicus. The results showed a higher sensitivity of the PCR assay in detecting the infection compared to parasitological methods.

The effect of phenolated "vaccines" against experimental T. cruzi infection in mice

"Vaccines" prepared from parasites of an avirulent cultivated Y strain of T. cruzi, suspended in phenolated 1/10.000 saline solution, with aluminum stearate, containing alive parasites, gave high degree of protection to mice against a posterior infection with virulent blood forms of the same parasites and strain. The degree of protection with 1/1000 and 1/10.000 phenol "vaccines", with no alive parasites, was very poor specially in the first group. The immunity seems to be related to the number of alive trypanosomes in the "vaccines".

Acute exacerbation in chronic hepatitis B virus infection

A case of an acute exacerbation of liver injury in a chronic HBV infected young male is reported. The correlation between the severe symptomatic hepatitis is done with the histopathologic findings of extense areas of bridging necrosis on the Iwer biopsy. The serological pattern for markers of HBV (HBsAg +, anti HBs g -, HBeAg -, anti HBe +, anti HBcIgG + and IgM -) confirm a chronic infection, ana the authors propose that the episode of severe hepatitis relates to the recent spontaneous seroconvertion of HBe Ag to anti HBe. Other causes of hepatitis were excluded, and the control liver biopsy (6 months later) showed normalization of hepatic architecture and absence of markers of viral replication in tissue and serum. A review of literature is done in an attempt to elucidate the diagnostic possibilities in this case, with emphasis on new immunoassays useful in differentiating between acute hepatitis B and acute exacerbation of a chronic hepatitis by the same virus.

The effect of Zymomonas mobilis culture on experimental Schistosoma mansoni infection

C57Bl/10 male mice infected with Schistosoma mansoni were distributed into mixed, prophylactic and curative groups. A culture of Zymomonas mobilis was orally administered to mice. A 61% protection from the infection was observed in the curative group (p <0.05). Histopathological study of the livers and intestines showed similar results.

Carbohydrate-rich high-molecular-mass antigens are strongly recognized during experimental Histoplasma capsulatum infection

INTRODUCTION: During histoplasmosis, Histoplasma capsulatum soluble antigens (CFAg) can be naturally released by yeast cells. Because CFAg can be specifically targeted during infection, in the present study we investigated CFAg release in experimental murine histoplasmosis, and evaluated the host humoral immune response against high-molecular-mass antigens (hMMAg. >150 kDa), the more immunogenic CFAg fraction. METHODS: Mice were infected with 2.2x10(4) H. capsulatum IMT/HC128 yeast cells. The soluble CFAg, IgG anti-CFAg, IgG anti-hMMAg, and IgG-hMMAg circulating immune complexes (CIC) levels were determined by enzymelinked immunosorbent assay, at days 0, 7, 14, and 28 post-infection. RESULTS: We observed a progressive increase in circulating levels of CFAg, IgG anti-CFAg, IgG anti-hMMAg, and IgG-hMMAg CIC after H. capsulatum infection. The hMMAg showed a high percentage of carbohydrates and at least two main immunogenic components. CONCLUSIONS: We verified for the first time that hMMAg from H. capsulatum IMT/HC128 strain induce humoral immune response and lead to CIC formation during experimental histoplasmosis.

Neuronal alterations in chronic cerebral Toxoplasma gondii infection

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2015

Experimental kinetics of infection induced by Yersinia pseudotuberculosis isolated from stock animals

The course of in vivo infection of five isolates of Yersinia pseudotuberculosis was followed for three weeks in Swiss mice. The strains were isolated from diarrheic and normal feces and mesenteric lymph nodes of healthy and sick stock animals. Four strains of serogroup O:3 and one of serogroup O:1a, with and without the virulence plasmid, were inoculated intragastrically and intravenously in the mice. Groups of five animals were sacrificed at 6 h and 3, 6, 10, 15, and 21 days after inoculation, and organs and tissues were checked for possible macroscopic alterations. Development of infection was monitored at these times by performing viable bacterial counts in homogenates of selected tissues. The animals were cheked daily for clinical alterations. The results of the study showed that strains with the virulence plasmid infected organs and tissues at various times and at varying intensity by both routes of infection, the strain of type O:1a being the most invasive. Moreover, clinical and pathological alterations occurred only in animals inoculated with bacteria carrying the virulence plasmid, regardless of the route of infection.

Alteration in the endogenous intestinal flora of swiss webster mice by experimental Angiostrongylus costaricensis infection

The association between worm infections and bacterial diseases has only recently been emphasized. This study examined the effect of experimental Angiostrongylus costaricensis infection on endogenous intestinal flora of Swiss Webster mice. Eight mice aging six weeks were selected for this experiment. Four were infected with A. costaricensis and the other four were used as controls. Twenty eight days after the worm infection, all mice in both groups were sacrificed and samples of the contents of the ileum and colon were obtained and cultured for aerobic and anaerobic bacteria. In the mice infected with A. costaricensis there was a significant increase in the number of bacteria of the endogenous intestinal flora, accompanied by a decrease in the number of Peptostreptococcus spp. This alteration in the intestinal flora of mice infected by the nematode may help to understand some bacterial infections described in humans.

Angiostrongylus costaricensis: complete redescription of the migratory pathways based on experimental Sigmodon hispidus infection

Angiostrongylus costaricensis lives in the cecal and mesenteric arteries of its vertebrate hosts, and causes an inflammatory disease in humans. To investigate unknown aspects of the abdominal angiostrogyliasis pathogenesis, infected Sigmodon hispidus were sequentially studied in different times of infection. The study revealed that L3 goes alternatively through two migratory courses during its development into an adult worm: lymphatic/venous-arterial and venous portal pathways. The former is considered the principal one, because it is used by most of the larvae. Like other metastrongylides, A. costaricensis passes over the pulmonary circulation to migrate from the lymphatic system to the arterial circulation, where they circulate during some days before reaching their definitive habitat. The oviposition by mature females began on 15th day. Eggs and L1 were detected mainly in the intestine and stomach, surrounded by inflammatory reaction constituted by macrophages, monocytes, and eosinophils. They were also spread to the lungs, mesenteric lymph nodes, pancreas, spleen, and kidneys. The larvae (L1) exhibited the centripetal capacity to invade the lymphatic and venous vessels of the intestine and mesentery. Adult worms that developed in the venous intrahepatic pathway migrated downstream to reach the mesenteric veins and laid eggs that embolized in the portal hepatic vessels.