A clinico-pathological study of 163 untreated cases of chronic hepatitis C

We performed a clinico-pathological study of 163 untreated cases of chronic hepatitis C. Eighty five percent of the patients were clinically asymptomatic and their physical examinations sbowed unremarkable or minimal changes at the time of the liver biopsy Liver function tests tended to present slight abnormalities, involving mild elevations of the activity of the aminotransferases and gamma-glutamil transferase levels. In spite of these mild abnormalities advanced chronic liver disease ivas histologically detected in eighty nine percent of the patients, mainly showing chronic active hepatitis. The most characteristic histological finding ivas an interlobular bile duct damage which correlated with the presence of tymphoid aggregates in the portal tracts and with the development of fibrosis.

Alterações da função hepática de camundongos desnutridos e infectados pelo Schistosoma mansoni

Existem poucos estudos sobre as alterações da função hepática em camundongos com esquistossomose associada à desnutrição. Neste trabalho, os animais foram divididos em quatro grupos, de acordo com as dietas (normal ou hipoprotéica) e infectados ou não pelo Schistosoma mansoni. Todos os grupos desenvolveram-se menos que o grupo controle (p<0,0001). A mortalidade nos animais foi devida à infecção. Níveis altos de aminotransferases nos animais nutridos e infectados sugerem um processo inflamatório intenso (p<0,0001). Todos os grupos apresentaram elevação da fosfatase alcalina. Houve aumento da aspartato transferase e da fosfatase alcalina em animais nutridos infectados. As dietas modificaram os níveis de albumina (p>0,001), e das proteínas séricas. Os grupos, comparados ao controle, mostraram baixos níveis de glicose (p<0,001). Este estudo verificou que ambas, infecção e/ou desnutrição, interferiram nos níveis dos indicadores bioquímicos, mas as alterações mais importantes da função hepática ocorreram durante a inflamação intensa causada pela esquistossomose.

Female alcoholics: electrocardiographic changes and associated metabolic and electrolytic disorders

OBJECTIVE: To identify the electrocardiographic changes and their associations with metabolic and electrolytic changes in female alcoholics. METHODS: The study comprised 44 female alcoholics with no apparent physical disorder. They underwent the following examinations: conventional electrocardiography; serologic tests for syphilis, Chagas' disease, and hepatitis B and C viruses; urinary pregnancy testing; hematimetric analysis; biochemical measurements of albumin, fibrinogen, fasting and postprandial glycemias, lipids, hepatic enzymes, and markers for tissue necrosis and inflammation. RESULTS: Some type of electrocardiographic change was identified in 33 (75%) patients. In 17 (38.6%) patients, more than one of the following changes were present: prolonged QTc interval in 24 (54.5%), change in ventricular repolarization in 11(25%), left ventricular hypertrophy in 6 (13.6%), sinus bradycardia in 4 (9.1%), sinus tachycardia in 3 (6.8%), and conduction disorder in 3 (6.8%). The patients had elevated mean serum levels of creatine phosphokinase, aspartate aminotransferases, and gamma glutamyl transferase, as well as hypocalcemia and low levels of total cholesterol and LDL-cholesterol. The patients with altered electrocardiograms had a more elevated age, a lower alcohol consumption, hypopotassemia, and significantly elevated levels of triglycerides, postprandial glucose, sodium and gamma glutamyl transferase than those with normal electrocardiograms. The opposite occurred with fasting glycemia, magnesium, and alanine aminotransferase. CONCLUSION: The electrocardiographic changes found were prolonged QTc interval, change in ventricular repolarization, and left ventricular hypertrophy. Patients with normal and abnormal electrocardiograms had different metabolic and electrolytic changes.

Estradiol transdérmico e perfil lipídico: efeitos em um grupo específico de mulheres brasileiras pós-menopausadas

FUNDAMENTO: Em mulheres pós-menopausadas, mudanças significantes ocorrem, que podem induzir doenças cardiovasculares, tais como o perfil lipídico aterogênico devido a um aumento nos níveis de colesterol total e LDL, e uma diminuição nos níveis de HDL. A terapia de reposição hormonal (TRH) pode evitar essas mudanças no perfil lipídico. OBJETIVO: Determinar os efeitos da TRH constituída por estradiol transdérmico e acetato de medroxiprogesterona nos parâmetros bioquímicos e lipídicos de mulheres brasileiras pós-menopausadas. MÉTODOS: Este é um estudo prospectivo, longitudinal, aberto, no qual trinta mulheres pós-menopausadas receberam estradiol em gel transdérmico (1 mg/dia) de forma contínua, combinado com acetato de medroxiprogesterona (MPA) (5 mg/dia) por 12 dias/mês. Os seguintes parâmetros foram determinados: colesterol total, triglicérides, lipoproteína de alta densidade (HDL-colesterol), lipoproteína de baixa densidade (LDL-colesterol), lipoproteína de muito baixa densidade (VLDL-colesterol), glicose, aspartato aminotransferase (AST), alanina aminotransferase (ALT), gama-glutamil transferase (GGT) e hormônio folículo estimulante (FSH). RESULTADOS: Os parâmetros do perfil lipídico mostraram uma diminuição não-significante, enquanto os níveis de GGT e FSH apresentaram uma diminuição estatisticamente significante. CONCLUSÕES: O tratamento com estradiol em gel transdérmico não mostrou um impacto significante no perfil lipídico, de forma que não resultou em um efeito benéfico nos marcadores de doenças cardiovasculares, sugerindo que a dose, modo de administração e o tempo de tratamento foram importantes para esses resultados. Além disso, o tratamento com dose baixa e modo de administração transdérmico também demonstrou um significante efeito hepático nessa população. Dessa forma, esse tratamento pode fornecer efeitos interessantes sobre o perfil lipídico em mulheres brasileiras pós-menopausadas.

Carvedilol atenua o estresse oxidativo na cardiopatia chagásica crônica

FUNDAMENTO: Há cada vez mais evidências sugerindo que doença de Chagas envolve dano oxidativo e contribui para a progressão da doença cardíaca. OBJETIVO: Avaliar o efeito do carvedilol sobre marcadores de estresse oxidativo na doença de Chagas crônica. MÉTODOS: A população de estudo incluiu 42 pacientes com cardiopatia chagásica e os biomarcadores de estresse oxidativo foram medidos antes e após um período de seis meses de tratamento com carvedilol (37,5 mg/dia). Os pacientes foram considerados de acordo com a classificação de Los Andes, e a atividade da superóxido dismutase, catalase, glutationa peroxidase, S-transferase e redutase, mieloperoxidase e adenosina deaminase; e os níveis de glutationa reduzida, de espécies reativas do ácido tiobarbitúrico, proteína carbonil, vitamina E e óxido nítrico foram medidos no sangue. RESULTADOS: Após o tratamento com carvedilol, todos os grupos apresentaram reduções significativas nos níveis de proteína carbonil e glutationa reduzida, enquanto os níveis de óxido nítrico e atividade da adenosina aumentaram significativamente somente no grupo IA. Além disso, a maioria das enzimas antioxidantes apresentou diminuição de suas atividades, nos grupos IA e IB. CONCLUSÃO: Os dados sugerem que o tratamento com carvedilol foi eficaz na atenuação do dano oxidativo, um efeito que pode ser particularmente importante em doença de Chagas crônica com cardiopatia.

O carvedilol potencializa o efeito antioxidante das vitaminas E e C na cardiopatia chagásica crônica

FUNDAMENTO: A doença de Chagas continua a ser uma importante doença endêmica no país, sendo o acometimento cardíaco a sua manifestação mais grave. OBJETIVO: Verificar se o uso concomitante de carvedilol potencializará o efeito antioxidante das vitaminas E e C na atenuação do estresse oxidativo sistêmico na cardiopatia chagásica crônica. MÉTODOS: Foram estudados 42 pacientes com cardiopatia chagásica, agrupados de acordo com a classificação modificada de Los Andes, em quatro grupos: 10 pacientes no grupo IA (eletrocardiograma e ecocardiograma normais: sem envolvimento do coração), 20 pacientes do grupo IB (eletrocardiograma normal e ecocardiograma anormal: ligeiro envolvimento cardíaco), oito pacientes no grupo II (eletrocardiograma e ecocardiograma anormais, sem insuficiência cardíaca: moderado envolvimento cardíaco) e quatro pacientes no grupo III (eletrocardiograma e ecocardiograma anormais com insuficiência cardíaca: grave envolvimento cardíaco). Os marcadores de estresse oxidativo foram medidos no sangue, antes e após um período de seis meses de tratamento com carvedilol e após seis meses de terapia combinada com vitaminas E e C. Os marcadores foram: atividades da superóxido dismutase, catalase, glutationa peroxidase, glutationa S-transferase e redutase, mieloperoxidase e adenosina deaminase, e os níveis de glutationa reduzida, de espécies reativas do ácido tiobarbitúrico, proteína carbonilada, vitamina E e óxido nítrico. RESULTADOS: Após o tratamento com carvedilol, todos os grupos apresentaram diminuições significativas dos níveis de proteína carbonilada e glutationa reduzida, enquanto os níveis de óxido nítrico e atividade da adenosina aumentaram significativamente apenas no grupo menos acometido (IA). Além disso, a maioria das enzimas antioxidantes mostrou atividades diminuídas nos grupos menos acometidos (IA e IB). Com a adição das vitaminas ao carvedilol houve diminuição dos danos em proteínas, nos níveis de glutationa e na maior parte da atividade das enzimas antioxidantes. CONCLUSÕES: A queda dos níveis de estresse oxidativo, verificada pelos marcadores testados, foi mais acentuada quando da associação do fármaco carvedilol com as vitaminas antioxidantes. Os dados sugerem que tanto o carvedilol isoladamente como sua associação com as vitaminas foram eficazes em atenuar o dano oxidativo sistêmico em pacientes com CC, especialmente aqueles menos acometidos, sugerindo a possibilidade de sinergismo entre esses compostos.

GP38, P28-I and P28-II: candidates for a vaccine against Schistosomiasis

Three antigens protective against Schistosoma mansoni have been extensively characterized. The schistosomulum surface antigen GP38 possesses an immunodominant carbohydrate epitope of which the structure has been defined. Protection can be achieved via the transfer of monoclonal antibodies recognizing the epitope or by immunization with anti-idiotype monoclonal antibodies. The glycan epitope is shared with the intermediate host, Biomphalaria glabrata as well as being present on other molluscs, including the Keyhole Limpet. A group of molecules at 28 kDa were initially characterized in adult worms and shown to protect rats and mice against a challenge infection. One of these molecules, P28-I, was cloned and expressed in E. coli, yeast and vaccinia virus. The recombinant antigen significantly protected rats, hamsters and baboons against a challenge infection. P28-I is a glutathione-S-transferase and the recombinant antigen produced in yeast exhibits the enzyme activity and has been purified to homogeneity by affinity chromatography. A second P28 antigen, P28-II, has also been cloned, fully sequenced and expressed. This recombinant antigen also protects against S. mansoni infection.

Medium-term protocols for in vivo evaluation of chemical modifiers of carcinogenesis

Cancer development is a long-term multistep process which allows interventional measure before the clincial disease emerges. the detection of natural substances which can block the process of carcinogenesis is a important as the identification of anti-tumoral drugs since they might be used in chemoprevention of cancer in high-risk groups. In vivo rodent models of chemical caecinogenesis have been used to study plant-derived inhibitors of carcinofenesis such as indols, coumarins, isothiocyanates, flavones, phenols and allyl-sulfides. Since the standard in vivo rodent bioassay is prolonged and expensive, shorter reliable protocols are needed. Two in vivo medium-term protocols for evaluation of modifiers of carcinogenesis are presented, one related to liver and the other to bladder cancer. Both protocols use rats, last 8 and 36 weeks and are based on the two-step concept of carcinogenesis: initiation and promotion. The protocols use respectively the development of altered foci of hepatocytes expressing immunochistochemically the placental form of gluthation S-transferase and the appearence of pre-neoplastic urothelium and papillomas as the "end-points". the use of these protocols for detection of plantpderived inhibitors of carcinogenesis appear warranted.

Vaccine strategies against schistosomiasis

Schistosomiasis, the second major parasitic disease in the world after malaria affects at least 200 million people, 500 million being exposed to the risk of infection. It is widely agreed that a vaccine strategy wich could lead to the induction of effector mechanisms reducing the level of reinfection and ideally parasite fecundity would deeply affect the incidence of pathological manifestations as well as the parasite transmission potentialities. Extensive studies performed in the rat model have allowed the identification of novel effector mechanisms involving IgE antibodies and various inflammatory cell populations (eosinophils, macrophages and platelets) whereas regulation of immune response by blocking antibodies has been evidencial. Recent epidemiological studies have now entirely confirmed in human populations the the role of IgE antibodies in the acquisition of resistance and the association of IgG4 blocking antibodies with increased susceptibility. On the basis of these concepts, several schistosome glutathion S-transferase (Sm 28 GST) appears as a pronising vaccine candidate. Immunization experiments have shown that two complementary goals can be achieved: (a) a partial but significant reduction of the worm population (up to 60//in rats); (b) a significant reduction of parasite fecundity (up in the mice and 85//in cattle) and egg viability (up to 80//). At least two distinct immunological mechanisms account for these two effects. IgE antibodies appear as a major humoral component of acquired resistance whereas IgA antibodies appear as a major humoral factor affecting parasite fecundity. These studies seem to represent a parasite diseases through the identification of potentially protective antigens and of the components of the immune response which vaccination should aim at inducing.

Development of a vaccine strategy against human and bovine schistosomiasis: background and update

Schistosomiasis is a chronic and debilitating parasitic disease that affects over 200 million people throughout the world and causes about 500,000 deaths annually. Two specific characteristics of schistosome infection are of primordial importance to the development of a vaccine: schistosomes do not multiply within the tissues of their definitive hosts (unlike protozoan parasites) and a partial non-sterilizing immunity can have a marked effect on the incidence of pathology and on disease transmission. Since viable eggs are the cause of disease pathology, a reduction in worm fecundity whether or not accompanied by a reduction in parasite burden is a sufficient goal for vaccine induced immunity. We originally showed that IgE antibodies played in experimental models a pivotal role for the development of protective immunity. These laboratory findings have been now confirmed in human populations. Following the molecular cloning and expression of a protein 28 kDa protein of Schistosoma mansoni and its identification as a glutathion S-transferase, immunization experiments have been undertaken in several animal species (rats, mice, baboons). Together with a significant reduction in parasite burden, vaccination with Sm28 GST was recently shown to reduce significantly parasite fecundity and egg viability leading to a decrease in liver pathology. Whereas IgE antibodies were shown to be correlated with protection against infection, IgA antibodies have been identified as one of the factors affecting egg laying and viability. In human populations, a close association was found between IgA antibody production to Sm28 GST and the decrease of egg output. The use of appropriate monoclonal antibody probes has allowed the demonstration that the inhibition of parasite fecundity following immunization was related to the inhibition of enzymatic activity of the molecule. Epitope mapping of Sm28 GST has indicated the prominent role of the N and C terminal domains. Immunization with the corresponding synthetic peptides was followed by a decrease of 70% of parasite fecundity and egg viability. As a preliminary step towards phase I human trials, vaccination experiments have been performed in cattle, a natural model for Schistosoma bovis. Vaccination of calves with the S. bovis GST has led to a reduction of ever 80% of egg output and tissue egg count. Significant levels of protection were also observed in goats after immunization with the recombinant S. bovis GST. Increasing evidence of the participation of IgA antibodies in protective immunity has prompted us toward the development of mucosal immunization. Preliminary results indicate that significant levels of protection can be achieved following oral immunization with live attenuated vectors or liposomes. These studies seem to represent a promising approach towards the future development of a vaccine strategy against one of major human parasitic diseases.

The WHO Collaborating Centre for Research and Control of Schistosomiasis at Niamey, Niger

The Centre de Recherche sur les Méningites et les Schistosomes (CERMES) is a research institute depending on the Organisation de Coordination et de Coopération pour la lutte contre les Grandes Endémies - a West African Organization for Public Health - devoted to the studies on schistosomiasis and meningitis. The staff includes 32 persons with 11 scientists and one financial officer. The activities of the CERMES involving schistosomiasis concern three research units: (a) ecology of human and animal schistosomiasis transmission; the CERMES defined the different patterns of schistosomiasis transmission in Niger (involving African dry savana); in this field, we have shown, (i) the existence of important variability in conditions of transmission of S. haematobium and, (ii) natural hybridization between parasitic species of the ruminants (S. bovis and S. curassoni) and genetic interaction between human and animal parasites; (b) definition of morbidity indicators usable for rapid assessment methods, for appraisal of the severity of the disease and for the evaluation of the efficiency of control methods; we have established the correlation between ultrasonographic data and some cheap and simple field indicators; (c) immune response and protective immunity induced by recombinant glutathion S-transferase (Sm28, Sb28 and Sh28) in homologous and heterologous animal models including goats, sheep and non human primates (Erythrocebus patas). In Niger, we participate in all control programs against schistosomiasis to define control strategies, to supervise operations and to participate in their evaluation with external experts. International collaborations constitute a frame including four laboratories in Africa and six laboratories in developed countries (Europe and USA)

The in vitro cytopathology of a porcine and the simian (SA-11) strains of rotavirus

Rotaviruses have been implicated as the major causal agents of acute diarrhoea in mammals and fowls. Experimental rotavirus infection have been associated to a series of sub-cellular pathologic alterations leading to cell lysis which may represent key functions in the pathogenesis of the diarrhoeic disease. The current work describes the cytopathic changes in cultured MA-104 cells infected by a simian (SA-11) and a porcine (1154) rotavirus strains. Trypan blue exclusion staining showed increased cell permeability after infection by both strains, as demonstrated by cell viability. This effect was confirmed by the leakage of infected cells evaluated by chromium release. Nuclear fragmentation was observed by acridine orange and Wright staining but specific DNA cleavage was not detected. Ultrastructural changes, such as chromatin condensation, cytoplasm vacuolisation, and loss of intercellular contact were shown in infected cells for both strains. In situ terminal deoxynucleotidyl transferase (Tunel) assay did not show positive result. In conclusion, we demonstrated that both strains of rotavirus induced necrosis as the major degenerative effect.

Effect of fosmidomycin on metabolic and transcript profiles of the methylerythritol phosphate pathway in Plasmodium falciparum

In Plasmodium falciparum, the formation of isopentenyl diphosphate and dimethylallyl diphosphate, central intermediates in the biosynthesis of isoprenoids, occurs via the methylerythritol phosphate (MEP) pathway. Fosmidomycin is a specific inhibitor of the second enzyme of the MEP pathway, 1-deoxy-D-xylulose-5-phosphate reductoisomerase. We analyzed the effect of fosmidomycin on the levels of each intermediate and its metabolic requirement for the isoprenoid biosynthesis, such as dolichols and ubiquinones, throughout the intraerythrocytic cycle of P. falciparum. The steady-state RNA levels of the MEP pathway-associated genes were quantified by real-time polymerase chain reaction and correlated with the related metabolite levels. Our results indicate that MEP pathway metabolite peak precede maximum transcript abundance during the intraerythrocytic cycle. Fosmidomycin-treatment resulted in a decrease of the intermediate levels in the MEP pathway as well as in ubiquinone and dolichol biosynthesis. The MEP pathway associated transcripts were modestly altered by the drug, indicating that the parasite is not strongly responsive at the transcriptional level. This is the first study that compares the effect of fosmidomycin on the metabolic and transcript profiles in P. falciparum, which has only the MEP pathway for isoprenoid biosynthesis.

RNA polymerase I promoter and splice acceptor site recognition affect gene expression in non-pathogenic Leishmania species

Leishmania (Sauroleishmania) tarentolae has biotechnological potential for use as live vaccine against visceral leishmaniasis and as a system for the over expression of eukaryotic proteins that possess accurate post-translational modifications. For both purposes, new systems for protein expression in this non-pathogenic protozoan are necessary. The ribosomal RNA promoter proved to be a stronger transcription driver since its use yielded increased levels of recombinant protein in organisms of both genera Trypanosoma or Leishmania. We have evaluated heterologous expression systems using vectors with two different polypyrimidine tracts in the splice acceptor site by measuring a reporter gene transcribed from L. tarentolae RNA polymerase I promoter. Our data indicate that the efficiency of chloramphenicol acetyl transferase expression changed drastically with homologous or heterologous sequences, depending on the polypyrimidine tract used in the construct and differences in size and/or distance from the AG dinucleotide. In relation to the promoter sequence the reporter expression was higher in heterologous lizard-infecting species than in the homologous L. tarentolae or in the mammalian-infecting L. (Leishmania) amazonensis.

Modification of oxidative status in Plasmodium berghei-infected erythrocytes by E-2-chloro-8-methyl-3-[(4'-methoxy-1'-indanoyl)-2'-methyliden]-quinoline compared to chloroquine

E-2-chloro-8-methyl-3-[(4'-methoxy-1'-indanoyl)-2'-methyliden]-quinoline (IQ) is a new quinoline derivative which has been reported as a haemoglobin degradation and ß-haematin formation inhibitor. The haemoglobin proteolysis induced by Plasmodium parasites represents a source of amino acids and haeme, leading to oxidative stress in infected cells. In this paper, we evaluated oxidative status in Plasmodium berghei-infected erythrocytes in the presence of IQ using chloroquine (CQ) as a control. After haemolysis, superoxide dismutase (SOD), catalase, glutathione cycle and NADPH + H+-dependent dehydrogenase enzyme activities were investigated. Lipid peroxidation was also assayed to evaluate lipid damage. The results showed that the overall activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were significantly diminished by IQ (by 53.5% and 100%, respectively). Glutathione peroxidase activity was also lowered (31%) in conjunction with a higher GSSG/GSH ratio. As a compensatory response, overall SOD activity increased and lipid peroxidation decreased, protecting the cells from the haemolysis caused by the infection. CQ shared most of the effects showed by IQ; however it was able to inhibit the activity of isocitrate dehydrogenase and glutathione-S-transferase. In conclusion, IQ could be a candidate for further studies in malaria research interfering with the oxidative status in Plasmodium berghei infection.