Safety of Oral P2Y12 Inhibitors in Interventional Neuroradiology: Current Status and Perspectives

In the field of interventional neuroradiology, antiplatelet agents are commonly used to prepare patients before the implantation of permanent endovascular materials. Among the available drugs, clopidogrel is the most frequently used one, but resistance phenomena are considered to be relatively common. Prasugrel and ticagrelor were recently added to the pharmacologic arsenal, but the safety of these agents in patients undergoing neurointerventional procedures is still a subject of discussion. The cumulative experience with both drugs is less extensive than that with clopidogrel, and the experience with patients in the neurology field is less extensive than in the cardiology domain. In the present article, we provide a narrative review of studies that investigated safety issues of oral P2Y12 inhibitors in interventional neuroradiology and discuss potential routes for future research.

NR3C1, ABCB1, TNF and CYP2C19 polymorphisms association with the response to the treatment of erythema nodosum leprosum

Aim: To evaluate the effects of gene polymorphisms in the treatment of erythema nodosum leprosum with prednisone/thalidomide. Patients & methods: A total of 152 patients from different regions of Brazil were included. Generalized estimating equation was used to evaluate the influence of polymorphisms and haplotypes on the drug dose variation throughout the treatment. Results: An association between the genotype tuberculoid of polymorphism ABCB1 3435C>T (rs1045642; p = 0.02) and prednisone dose was found in the recessive model. An association between the haplotypes 1031T/-863C/-857C/-308A/-238G (p = 0.006) and 1031T/-863C/-857T/-308A/-238G (p = 0.040) of the TNF gene and the CYP2C19*2 polymorphism were also identified, in relation to thalidomide dosage variation over the course of treatment. Conclusion: This work presents the first pharmacogenetic report of association between gene polymorphisms and erythema nodosum leprosum treatment with prednisone/thalidomide.

Rare disruptive variants in the DISC1 Interactome and Regulome: association with cognitive ability and schizophrenia

Schizophrenia (SCZ), bipolar disorder (BD) and recurrent major depressive disorder (rMDD) are common psychiatric illnesses. All have been associated with lower cognitive ability, and show evidence of genetic overlap and substantial evidence of pleiotropy with cognitive function and neuroticism. Disrupted in schizophrenia 1 (DISC1) protein directly interacts with a large set of proteins (DISC1 Interactome) that are involved in brain development and signaling. Modulation of DISC1 expression alters the expression of a circumscribed set of genes (DISC1 Regulome) that are also implicated in brain biology and disorder. Here we report targeted sequencing of 59 DISC1 Interactome genes and 154 Regulome genes in 654 psychiatric patients and 889 cognitively-phenotyped control subjects, on whom we previously reported evidence for trait association from complete sequencing of the DISC1 locus. Burden analyses of rare and singleton variants predicted to be damaging were performed for psychiatric disorders, cognitive variables and personality traits. The DISC1 Interactome and Regulome showed differential association across the phenotypes tested. After family-wise error correction across all traits (FWERacross), an increased burden of singleton disruptive variants in the Regulome was associated with SCZ (FWERacross P=0.0339). The burden of singleton disruptive variants in the DISC1 Interactome was associated with low cognitive ability at age 11 (FWERacross P=0.0043). These results identify altered regulation of schizophrenia candidate genes by DISC1 and its core Interactome as an alternate pathway for schizophrenia risk, consistent with the emerging effects of rare copy number variants associated with intellectual disability.

Effects of simvastatin/ezetimibe on microparticles, endothelial progenitor cells and platelet aggregation in subjects with coronary heart disease under antiplatelet therapy

It is not known whether the addition of ezetimibe to statins adds cardiovascular protection beyond the expected changes in lipid levels. Subjects with coronary heart disease were treated with four consecutive 1-week courses of therapy (T) and evaluations. The courses were: T1, 100 mg aspirin alone; T2, 100 mg aspirin and 40 mg simvastatin/10 mg ezetimibe; T3, 40 mg simvastatin/10 mg ezetimibe, and 75 mg clopidogrel (300 mg initial loading dose); T4, 75 mg clopidogrel alone. Platelet aggregation was examined in whole blood. Endothelial microparticles (CD51), platelet microparticles (CD42/CD31), and endothelial progenitor cells (CD34/CD133; CDKDR/CD133, or CD34/KDR) were quantified by flow cytometry. Endothelial function was examined by flow-mediated dilation. Comparisons between therapies revealed differences in lipids (T2 and T3<T1 and T4 for total cholesterol, LDL-C, and triglycerides; P<0.002 for all), as well as for endothelial function (T2>T1 and T4, P=0.001). Decreased platelet aggregation was observed after aspirin (arachidonic acid, T1<T3 and T4, P=0.034) and clopidogrel (adenosine, T3 and T4<T1 and T2, P<0.0001) therapy. Simvastatin/ezetimibe diphosphate did not change platelet aggregation, the amount of circulating endothelial and platelet microparticles, or endothelial progenitor cells. Cardiovascular protection following therapy with simvastatin/ezetimibe seems restricted to lipid changes and improvement of endothelial function not affecting the release of microparticles, mobilization of endothelial progenitor cells or decreased platelet aggregation.

Fenton chemistry and oxidative stress mediate the toxicity of the beta-amyloid peptide in a Drosophila model of Alzheimer's disease

The mechanism by which aggregates of the β-amyloid peptide (Aβ) mediate their toxicity is uncertain. We show here that the expression of the 42-amino-acid isoform of Aβ (Aβ_1–42) changes the expression of genes involved in oxidative stress in a Drosophila model of Alzheimer’s disease. A subsequent genetic screen confirmed the importance of oxidative stress and a molecular dissection of the steps in the cellular metabolism of reactive oxygen species revealed that the iron-binding protein ferritin and the H₂O₂ scavenger catalase are the most potent suppressors of the toxicity of wild-type and Arctic (E22G) Aβ_1–42. Likewise, treatment with the iron-binding compound clioquinol increased the lifespan of flies expressing Arctic Aβ_1–42. The effect of iron appears to be mediated by oxidative stress as ferritin heavy chain co-expression reduced carbonyl levels in Aβ_1–42 flies by 65% and restored the survival and locomotion function to normal. This was achieved despite the presence of elevated levels of the Aβ_1–42. Taken together, our data show that oxidative stress, probably mediated by the hydroxyl radical and generated by the Fenton reaction, is essential for Aβ_1–42 toxicity in vivo and provide strong support for Alzheimer’s disease therapies based on metal chelation.

The aetiological agents of American cutaneous leishmaniasis in the municipality of Monte Negro, Rondônia state, western Amazonia, Brazil

Although American cutaneous leishmaniasis (ACL) is one of the most important endemic diseases in the Brazilian state of Rondônia, there is very little information on the species of parasite involved. The objective of the present study was to identify the Leishmania species causing ACL in the Monte Negro municipality of the state. Over a 6-year period (1997-2002), the skin lesions of 233 patients were examined while the patients were attending an outpatients' clinic at the University of São Paulo's Advanced Research Unit in Monte Negro. ACL was diagnosed in 137 (58.8%) of the patients and leishmanial parasites were successfully isolated from 14 of the ACL cases. Using a panel of 24 monoclonal antibodies, 12 of the 14 isolates were identified, as L. (Viannia) braziliensis (seven), L. (V.) lainsoni (one), a L. (V.) lainsoni-like species (two), a L. (V.) guyanensis-like species (one), or a L. (Viannia) species that was different from all named species (one). These are the first records of human infection with L. (V.) braziliensis and L. (V.) lainsoni in Rondônia.

Disrupted in Schizophrenia 1 Interactome: evidence for the close connectivity of risk genes and a potential synaptic basis for schizophrenia

Disrupted in Schizophrenia 1 (DISC1) is a schizophrenia risk gene associated with cognitive deficits in both schizophrenics and the normal ageing population. In this study, we have generated a network of protein-protein interactions (PPIs) around DISC1. This has been achieved by utilising iterative yeast-two hybrid (Y2H) screens, combined with detailed pathway and functional analysis. This so-called 'DISC1 interactome' contains many novel PPIs and provides a molecular framework to explore the function of DISC1. The network implicates DISC1 in processes of cytoskeletal stability and organisation, intracellular transport and cell-cycle/division. In particular, DISC1 looks to have a PPI profile consistent with that of an essential synaptic protein, which fits well with the underlying molecular pathology observed at the synaptic level and the cognitive deficits seen behaviourally in schizophrenics. Utilising a similar approach with dysbindin (DTNBP1), a second schizophrenia risk gene, we show that dysbindin and DISC1 share common PPIs suggesting they may affect common biological processes and that the function of schizophrenia risk genes may converge.

The benzamide MS-275 is a potent, long-lasting brain region-selective inhibitor of histone deacetylases

The association of the histone deacetylase (HDAC) inhibitor valproate (VPA) with atypical antipsychotics has become a frequent treatment strategy for schizophrenia and bipolar disorder. Because the VPA doses administered are elevated, one cannot assume that the benefits of the VPA plus antipsychotic treatment are exclusively related to the covalent modifications of nucleosomal histone tails. We compared the actions of N-(2-aminophenyl)-4-[N-(pyridin-3-yl-methoxycarbonyl)aminomethyl]benzamide derivative (MS-275), which is a potent HDAC inhibitor in vitro, with the actions of VPA for their ability to (i) increase the acetylated status of brain nucleosomal histone tail domains and (ii) to regulate brain histone-RELN and histone-GAD(67) promoter interactions. MS-275 increases the content of acetylhistone 3 (Ac-H3) in the frontal cortex. Whereas this response peaks after a s.c. injection of 15 micromol/kg, the increase in Ac-H3 content in the hippocampus becomes significant only after an injection of 60 micromol/kg, suggesting that MS-275 is 30- to 100-fold more potent than VPA in increasing Ac-H3 in these brain regions. In contrast to VPA, MS-275, in doses up to 120 micromol/kg, fails to increase Ac-H3 content in the striatum. Chromatin immunoprecipitation shows that MS-275 increases Ac-H3-RELN and Ac-H3-GAD(67) promoter interaction in the frontal cortex. These results suggest that MS-275 is a potent brain region-selective HDAC inhibitor. It is likely that, in addition to MS-275, other benzamide derivatives, such as sulpiride, are brain-region selective inhibitors of HDACs. Hence, some benzamide derivatives may express a greater efficacy than VPA as an adjunctive to antipsychotics in the treatment of epigenetically induced psychiatric disorders.

Subcellular targeting of DISC1 is dependent on a domain independent from the Nudel binding site

Disrupted in schizophrenia 1 (DISC1) has been identified as a putative risk factor for schizophrenia and affective disorders through study of a Scottish family with a balanced (1;11) (q42.1;q14.3) translocation, which results in the disruption of the DISC1 locus and cosegregates with major psychiatric disease. Several other reports of genetic linkage and association between DISC1 and schizophrenia in a range of patient populations have added credibility to the DISC1-schizophrenia theory, but the function of the DISC1 protein is still poorly understood. Recent studies have suggested that DISC1 plays a role in neuronal outgrowth, possibly through reported interactions with the molecules Nudel and FEZ1. Here we have analyzed the DISC1 protein sequence to identify previously unknown regions that are important for the correct targeting of the protein and conducted imaging studies to identify DISC1 subcellular location. We have identified a central coiled-coil region and show it is critical for the subcellular targeting of DISC1. This domain is independent from the C-terminal Nudel binding domain highlighting the multidomain nature/functionality of the DISC1 protein. Furthermore, we have been able to provide the first direct evidence that DISC1 is localized to mitochondria in cultured cortical neurons that are dependent on an intact cytoskeleton. Surprisingly, Nudel is seen to differentially associate with mitochondrial markers in comparison to DISC1. Disruption of the cytoskeleton results in colocalization of Nudel and mitochondrial markers-the first observation of such a direct relationship. Mitochondrial dysfunction has been implicated to play a role in schizophrenia so we speculate that mutations in DISC1 or Nudel may impair mitochondrial transport or function, initiating a cascade of events culminating in psychiatric illness.

Disrupted in Schizophrenia 1 and Nudel form a neurodevelopmentally regulated protein complex: implications for schizophrenia and other major neurological disorders

Disrupted In Schizophrenia 1 (DISC1) was identified as a potential susceptibility gene for schizophrenia due to its disruption by a balanced t(1;11) (q42;q14) translocation, which has been shown to cosegregate with major psychiatric disease in a large Scottish family. We have demonstrated that DISC1 exists in a neurodevelopmentally regulated protein complex with Nudel. The complex is abundant at E17 and in early postnatal life but is greatly reduced in the adult. Nudel has previously been shown to bind Lis1, a gene underlying lissencephaly in humans. Critically, we show that the predicted peptide product resulting from the Scottish translocation removes the interaction domain for Nudel. DISC1 interacts with Nudel through a leucine zipper domain and binds to a novel DISC1-interaction domain on Nudel, which is independent from the Lis1 binding site. We show that Nudel is able to act as a bridge between DISC1 and Lis1 to allow formation of a trimolecular complex. Nudel has been implicated to play a role in neuronal migration, together with the developmental variation in the abundance of the DISC1-Nudel complex, may implicate a defective DISC1-Nudel complex as a neurodevelopmental cause of schizophrenia.

Malaria control in an agro-industrial settlement of Rondônia (Western Amazon region, Brazil)

A malaria control pilot project was developed in the Urupá agro-industrial farm that is situated in the State of Rondônia (Western Amazon Region, Brazil). Around 180 inhabitants had been surveyed for the past five years. The control measures were based on (1) training a community agent to perform on the spot microscopical diagnosis of malaria and to treat the uncomplicated cases of malaria; (2) limiting the use of insecticides to a short period before the high transmission season. This resulted in a significant reduction in the time between the onset of clinical symptoms and specific chemotherapy which fell from 3.5 to 1.3 days. In relation to the previous three reference years the total number of malaria cases was reduced to 50% in the first year and to 25% in the second year. The introduction of these measures coincided with pronounced reduction in the frequency of Plasmodium falciparum infections but this was less marked for P. vivax infections. In the second year of the pilot experiment there was no P. falciparum transmission on the farm. During the last decade there was a general decrease in the endemicity of malaria in the State of Rondônia. The linear regression coefficient values indicate that the decline was more pronounced in Urupá than in the general municipality and that the falciparum malaria API in Urupá farm is significantly lower than in the general municipality of Candeias were the farm is situated.

The epidemiology of malaria in Rondonia (Western Amazon region, Brazil): study of a riverine population

We report on a longitudinal study concerning the incidence of malaria in a riverine population (Portuchuelo) settled on the riverbanks of Rio Madeira, in the State of Rondonia, Brazil. We found the incidence of malaria to be seasonal, prevailing in the dry months of June and July. The Annual Parasite Index (API) was 292/1000 inhabitants, almost three times that of the state of Rondonia for the same period. In contrast with other studied Rondonian populations, malaria in Portuchuelo was more prevalent in youngsters < 16 years old, particularly in the 0-1 year age group. Adults were relatively spared, particularly those over 50 years. Besides being indicative of indoor transmission, these facts may suggest the existence of a certain degree of acquired resistance to infection and/or of lessened symptoms in older people. Riverine populations are spread over the entire Amazon region where most of its members were born. Due to the permanent presence of malaria among riverine populations, we are proposing that they may act as perennial reserves of malaria and, therefore, as sources of infection for migrants or eventual settlers at their vicinity. To date, the opposite view has been generally held. Anopheles darlingi, the main vector species in the area, is essentially sylvatic, which contributes to make the control of malaria highly problematic. The only hopes for control rest on permanent surveillance and the prompt treatment of patients, which are also problematic considering the vastness of the Amazon region and the remoteness of some of its riverine settlements.

[The evaluation of the efficacy of artesunate combined with tetracycline in the therapy of falciparum malaria]

A controlled clinical therapeutic study in hospitalized patients compared artesunate with quinine and mefloquine in patients with uncomplicated falciparum malaria. Forty two patients entered the trial and the follow up was for 28 days with thick blood film taken every 12 hours until became negative. Laboratory examinations included haematological and biochemical tests before and after treatment. Patients had a mean parasitaemia of 42.568 per microliter. Twenty six patients completed 28 days of follow up but 16 did not fulfil this protocol. One in each of the therapeutic groups showed delayed R I resistance. A further patient in the quinine group showed R III resistance. The cure rate was 88.8% for artesunate. 85.7% for mefloquine and 81.8% for quinine; no significant difference was found, the same occurring with the clearance of fever. The artesunate group had a quicker parasitaemia clearance time (37.3 +/- 11.5 hours) when compared with quinine (65.2 +/- 17.4) showing a significant difference (p = 0.0016). Parasite clearance with mefloquine, was intermediate (58.9 +/- 16.6 ours) between the artesunate and quinine. No important side effects were observed with any of the therapeutic regimens and no deaths registered.

Humoral immune response to the 72 kDa heat shock protein from Plasmodium falciparum in populations at hypoendemic areas of malaria in western Brazilian Amazon

The heat-shock protein Pf72/Hsp70-1 from the human malaria parasite Plasmodium falciparum has been suggested as a potential candidate antigen for a multivalent vaccine. We have investigated the prevalence and levels of IgG antibodies to the recombinant protein PfR44, derived from Pf72/Hsp70-1, in individuals from different age groups living in Candeias do Jamari, an Amazonian town characterized by unstable and hypoendemic malaria transmission. Blood were collected from a household-based random sample comprising 241 people and the sera were comparatively tested against recombinant antigen PfR44 and a detergent-soluble extract of P. falciparum (PfAg-T). The prevalence and levels of IgG antibodies to both recombinant and total P. falciparum antigens were positively correlated with cumulative exposure to malaria, as estimated by the age of the individuals and the duration of their stay in the study area. Nevertheless, correlations between antibody responses to Pf72/Hsp70-1 and the acquisition of protective anti-malarial immunity could not be derived from our data.

Hypoendemic malaria in Rondonia (Brazil, western Amazon region): seasonal variation and risk groups in an urban locality

A longitudinal epidemiologic survey (1989-1991) plus a cross-sectional parasitologic, clinical, and sociodemographic survey (July-October 1990) were conducted in Candeias do Jamary, a village with approximately 7,000 inhabitants in Rondonia, Brazil. Analysis of the results revealed hypoendemic malaria with a complex epidemiology. Plasmodium vivax predominated over P. falciparum infections while infections with P. malariae were absent. Malaria is present throughout the year but was clearly seasonal with epidemic outbreaks in the dry season from June to August. Malaria prevalence was lower in children less than 10 years of age and significantly higher in young adult males, which represent the high-risk group. The incidence of locally acquired infections (autochthonous cases) was significantly lower in the rainy season as compared with the dry season. This is not true with respect to heterotochthonous (imported) malaria cases, that is, malaria acquired elsewhere by Candeias residents, most of whom are male adults working outside the town. In both cases, however, the age and sex distribution of prevalence and its relationship with occupational activities indicate a predominance of outdoor transmission. The results of the cross-sectional survey are in agreement with those of the longitudinal passive survey and, in addition, disclose the absence of asymptomatic infection.

Unstable hypoendemic malaria in Rondonia (western Amazon region, Brazil): epidemic outbreaks and work-associated incidence in an agro-industrial rural settlement

A longitudinal study was conducted from January 1991 to January 1992 on the Urupa farm, a rural agro-industrial forestry settlement in Rondonia state (Western Amazon Region, Brazil) to define the parasitologic and clinical profile of malaria. Three cross-sectional, parasitologic, and clinical surveys were performed. In the intervals between surveys, malaria cases were monitored by twice a week medical visits to the farm and permanent local surveillance. The population of residents was approximately 170 and was characterized by high mobility. The slide positive rates found in the cross-sectional surveys were 0.5, 4.2 and 2.1, respectively, for the total population (Plasmodium vivax plus P. falciparum). Spleen rate values in children 2-9 years old were always less than 1%. However, this basically hypoendemic malaria situation was unstable, with occurrence of a typical epidemic outbreak at the end of the dry season. The total number of malaria cases recorded from January to December 1991 was 163, giving an annual parasite index of 970 per 1,000 inhabitants. However, sex and age distribution of cases showed rare incidence of malaria in infants and low incidence in children less than the age of 10. Male adults 16-40 years of age represented the main risk group. The observed clustering of cases allowed us to identify the place of work as a factor responsible for high incidence of malaria among adults. The general epidemiologic profile indicated that indoors transmission of malaria by the local Anopheles vector was low or absent.

Characterization of naturally acquired human IgG responses against the N-terminal region of the merozoite surface protein 1 of Plasmodium vivax

The primary structure of the merozoite surface protein 1 of Plasmodium vivax (PvMSP-1) revealed the existence of conserved and polymorphic blocks of the protein among different Plasmodium species. To characterize the naturally acquired IgG antibody responses to the PvMSP-1 molecule, the entire N-terminal portion of this protein was expressed as 10 overlapping glutathione S-transferase fusion proteins. The affinity-purified recombinant products were tested by enzyme-linked immunosorbent assay and Western blot against the sera of malaria patients from the state of Rondonia, Brazil. We found that the majority of these sera did not contain IgG antibodies recognizing recombinant proteins expressing exclusively interspecies conserved blocks of the molecule. In contrast, a high proportion of these same sera reacted against recombinant products expressing interspecies polymorphic regions of this protein. The poor B cell immunogenicity of the interspecies conserved blocks of the PvMSP-1 molecule most likely reflects important and unknown structural or functional features of these regions.

Antibody response against Plasmodium falciparum exoantigens and somatic antigens: a longitudinal survey in a rural community in Rondônia, western Brazilian Amazon

Three clinical and sero-epidemiological cross-sectional surveys involving 50 subjects were performed at six-month intervals in Urupá, a rural community characterized by unstable malaria transmission, situated in Rondônia State, Western Brazilian Amazon. Between the surveys, a clinically and parasitologically passive surveillance was established in this community and 48 malaria attacks (28 due to Plasmodium falciparum and 20 due to Plasmodium vivax) were recorded in this cohort of 50 subjects. Serum samples were collected at each survey and tested by enzyme immunoassay (ELISA) for IgG, IgG subclass and IgM antibodies against P. falciparum exoantigens isolated from culture supernatants and detergent-soluble somatic antigens. As expected, both anti-malarial IgG and IgM antibody titres were shown to rise after a malaria outbreak observed during the follow-up period. Nevertheless, in marked contrast with the profile of anti-malarial IgG subclasses described for semi-immune Africans, in this Amazonian community IgG2 antibodies (that are non-cytophilic) against both antigens were shown to predominate over other IgG subclasses. Such overall predominance of IgG2 subclass titres was statistically significant concerning exoantigens, but was of borderline significance in relation to IgG1 antibodies against somatic antigens (p = 0.052). Moreover, highly variable patterns of boosting were observed in antibody responses against both antigens among the patients who suffered P. falciparum malaria attack during the study.

Anaemia, iron deficiency and malaria in a rural community in Brazilian Amazon

OBJECTIVE

To assess the incidence of anaemia, iron deficiency and malaria in a malaria-endemic community.

DESIGN

Three consecutive cross-sectional surveys (A, B and C) of the whole population made at 6-month intervals and malaria surveillance between the surveys.

SETTING

Urupá, a rural community in Western Brazilian Amazon.

SUBJECTS

133 people of all age groups present in at least two cross-sectional surveys.

INTERVENTIONS

Anaemic patients received ferrous sulphate during 3 months. Patients parasitized by intestinal nematodes were given mebendazole and parasitologically proven Plasmodium falciparum and P. vivax malaria attacks were treated with quinine or chloroquine plus primaquine.

RESULTS

Anaemia (haemoglobin concentrations [Hb] below the cut-off values proposed by the World Health Organization) was diagnosed in respectively 10.0% (13 of 130) subjects in survey A, 9.2% (10 of 109) in B and 29.7% (27 of 91) in C. Depleted iron stores [serum ferritin (SF) < 12 micrograms/l] were detected in 10.0% subjects in survey A, 10.1% in B but in only 8.8% subjects in survey C. Concomitant anaemia and low SF was detected in 5.4% subjects in survey A, 3.7% in B and 6.6% in C. Mean Hb from anaemic patients diagnosed and treated during the study (n = 17) raised 1.2 g/dl after iron therapy and most of them (13 of 17, 76.5%) became non-anaemic. The highest malaria transmission was observed between surveys B and C. People who suffered at least one malaria attack during this period (27 of 63) were at a slightly greater risk of subsequent anaemia (odds ratio = 2.85, 95% confidence interval 0.81-10.28).

CONCLUSIONS

Both malaria and iron deficiency could be considered as important causes of anaemia in this population.

SPONSORSHIP

Supported by grants from the UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (no. 890245), the Ministére des Affaires Etrangeres, France, and from the Fundação de Amparo à Pesquisa do Estado de São Paulo (no. 92/1336-4). M.A.C. was supported by a doctoral fellowship from the Conselho Nacional de Desenvolvimento Científico e Tecnológico.

Human IgG responses against the N-terminal region of the Merozoite Surface Protein 1 of Plasmodium vivax

The complete primary structure of the gene encoding the Merozoite Surface Protein 1 of Plasmodium vivax (PvMSP-1) revealed the existence of interspecies conserved regions among the analogous proteins of other Plasmodia species. Here, three DNA recombinant clones expressing 50, 200 and 500 amino acids from the N-terminal region of the PvMSP-1 protein were used on ELISA and protein immunoblotting assays to look at the IgG antibody responses of malaria patients from the Brazilian amazon region of Rondônia. The results showed the existence of P. vivax and P. falciparum IgG antibodies directed against PvMSP-1 antigenic determinants expressed in the clones containing the first 200 and the following 500 amino acids of the molecule, but not within the one expressing the most N-terminal 50 amino acids. Interestingly, there was no correlation between the levels of these IgG antibodies and the previous number of malaria infections.

Longitudinal study of naturally acquired humoral immune responses against the merozoite surface protein 1 of Plasmodium vivax in patients from Rondonia, Brazil

A longitudinal study on the naturally acquired humoral immune responses against the merozoite surface protein 1 of Plasmodium vivax (PvMSP-1) was performed in malaria patients from the Brazilian Amazon region of Rondonia. We have previously cloned and expressed a recombinant protein, ICB2-5, that encodes 508 amino acids from the N-terminal portion of the PvMSP-1 protein. This affinity-purified polypeptide was tested by an enzyme-linked immunosorbent assay in a one-year longitudinal study using sera from 34 patients who had at least one malaria infection during the study period. The results demonstrated that more than 90% of the sera from patients having experienced more than three previous malaria infections contained antibodies to ICB2-5 at the time of a new clinical episode. Unexpectedly, more than half of these multiple-infected patients had an antibody response to ICB2-5 in which the predominant isotype was IgM. In contrast, more than 83% of the sera from these same patients contained predominantly IgG antibodies against total blood-stage antigen preparations. To determine if these results were due to the lack of boosting against this portion of the PvMSP-1 molecule, the presence of IgG antibodies to ICB2-5 in the sera from 11 patients who had consecutive malarial episodes during the study year was investigated. Five of these eleven patients failed to produce IgG antibodies to ICB2-5 even after 1-3 infections. Thus, these results suggest that no boosting against this region of the PvMSP-1 molecule was achieved by natural infections among these patients.

Prevalence and levels of IgG and IgM antibodies against Plasmodium falciparum and P. vivax in blood donors from Rondônia, Brazilian Amazon

Antibodies of IgG and IgM isotypes reacting with Plasmodium falciparum and P. vivax thicksmear antigens were searched for by the indirect fluorescent antibody test (IFAT) in a random sample of 230 blood donors at the transfusion centre of Porto Velho (HEMERON), Rondônia State, western Brazilian Amazon. A high prevalence of IgG seropositivity (32% against P. falciparum, 24% against P. vivax and 37% against either P. falciparum or P. vivax antigens) was detected among them, despite the fact that candidates reporting recent (< 12 months) malaria attacks were not eligible. Only a small proportion of them had also detectable IgM antibodies to these antigens. These data suggest an intense, relatively recent exposure to malaria in such an urban population sample. However, parasitaemia (as detected by microscopical examination of Giemsa-stained thick smears) was patent in only one prospective donor. The antibody profile of blood donors was compared with that of healthy subjects of all age groups, living in a close endemic area (Candeias village, 21 km east of Porto Velho). The villagers were classified into two groups according to their history of a recent (< 12 months) or a remote (> 12 months) past malaria attack due to either P. falciparum or P. vivax. Extensive overlapping was observed when the distribution of antibody titres of healthy subjects from Candeias village with a recent and remote malaria history was compared. In conclusion, subjects with a recent or a remote malaria history could not be distinguished by serological criteria alone.

Detection of antigens in the urine of patients with acute Plasmodium vivax malaria

Plasmodium antigens were detected by dot-blot assay in the urine of 50 patients infected with Plasmodium vivax. Antigens also were detected in 12/15 patients who no longer had detectable parasitemia, 3 weeks after chemotherapy. Antigenuria was negative 6 weeks after treatment. By Western blotting, four predominant protein antigens were identified in the urine of patients infected with P. vivax: 200, 180, 150, and 110 kDa. The dot-blot technique may prove to be a rapid and inexpensive method for diagnosing malaria in field studies and for clinical evaluation during chemotherapy.

[Anemia in a population from an endemic area of malaria, Rondônia (Brazil)]

With the purpose of describing the prevalence rate of anaemia among inhabitants of a malaria endemic area--Candeias district, a periurban locality near Porto Velho, in Rondônia State, Brazilian Amazon Basin--a random population sample comprehending 1,068 individuals of all age groups (14.1% of the total population) was screened for anaemia (measurement of blood haemoglobin concentration) and malaria (Giemsa-stained thick-smear microscopy). Two-hundred and ninety-nine individuals (28.0% of the sample) were found to be anaemic, using the cut-off haemoglobin values proposed by the World Health Organization for each age group. Highest prevalence rates were found among children with ages varying from 6 months to 1 year (70.0%) and from 1 to 6 years (38.4%), as well as in pregnant women (41.2%, 7/17) and malaria patients (44.4%, 8/18). Parasitological stoll examinations were made on a voluntary sample of 476 individuals (44.6% of the sample population); of these, 118 (26.8%) were positive. Eggs of Ascaris lumbricoides, the most frequent intestinal parasite in this population sample, was detected in 67 stool samples (14.1%); only 27 patients (5.7%) eliminated Ancylostomidae eggs. In this voluntary sample, no significant difference in anaemia prevalence rates between parasite carriers and non-parasited individuals was detected. On the other hand, the more recent the last malarial episode referred to by the patients, the lighter prevalence rate of anaemia in individuals above the age of 14 years. The role played by malaria as an underlying cause of anaemia in Candeias district inhabitants, particularly in the economically active age group, is further discussed.

Intestinal parasites among Karitiana Indians from Rondônia State, Brazil

Gravity sedimentation parasitological examinations were performed in stool samples from 111 Karitiana Indians from Rondônia State, Brazilian Amazon Basin. Intestinal parasites were found in 43 samples (38.7%). Ascaris lumbricoides was the most prevalent helminth species (18.9%). Egg counts in samples positive for Ascaris suggested an overdispersed distribution of worm burdens in the host population. Age-distribution pattern of intestinal parasites among Karitiana Indians was found to be rather unusual: the highest prevalence (60.0%) was detected in the 12- to 16-year-old age group.

[Mortality due to Chagas disease in São Paulo State (Brazil): subsidy for the planning of chagasic patient care]

In order to estimate the size of the population with Chagas' disease, an essential parameter for the establishment of an adequate health care policy for this group of patients, data from 1,646 death certificates from the "Fundação Sistema Estadual de Análises de Dados" in which Chagas' disease was mentioned in the State of S. Paulo in 1987 were examined. The population under study comprised adults between 15 and 70 years of age. Objectives also included the determination of Proportional Mortality, Potentially Lost Years of Life and regional distribution of the events in the counties of the State of S. Paulo. Chagas disease accounted for 0.9% of the totality of the causes of death, Proportional Mortality was 1.2% and the proportional participation of Chagas' disease in the Potentially Lost Years of Life was 1.1%. Corresponding data for Ischemic Heart Disease were, 4.0% and 1.2%. 20.8% of the deaths occurred in counties other than the county of residence, the indexes of evasion varying from 17.8% to 29.1% for different regions. Males (22.8%) more often than females (17.4%) died outside their county of residence. The largest number of deaths occurred in the metropolitan area of S. Paulo, although Ribeirão Preto county presented the highest mortality indexes.

Malaria seroepidemiology: comparison between indirect fluorescent antibody test and enzyme immunoassay using bloodspot eluates

Blood sampling on filter paper is a current practice in malaria seroepidemiological studies by indirect fluorescent antibody test (IFAT). There is, however, scant comparative information about the use of bloodspot eluates for detection of malarial IgG antibodies simultaneously by IFAT and enzyme immunoassay (ELISA). Here we report data obtained by both serological methods done on 219 bloodspot eluate samples collected in a rural community in Brazilian Amazon Basin (Alto Paraíso, Ariquemes municipality) where malaria is endemic. Plasmodium falciparum and P. vivax thick smear antigens were used in the IFAT; a detergent-soluble P. falciparum antigen was prepared for ELISA. Substantial agreement of results (Kappa coefficient k = 0.686) was observed when P. falciparum antigen was used in both tests, and IFAT titers were found to be strongly correlated to ELISA antibody units (Spearman correlation coefficient rs = 0.818, p < 0.001). Only moderate agreement (k = 0.467) between IFAT with P. vivax antigen and ELISA with P. falciparum antigen was observed. Spearman correlation coefficient value between quantitative results (IFAT titers and ELISA antibody units) in this case was numerically lower (rs = 0.540, p < 0.0001). Our results suggest that, with P. falciparum antigen, both IFAT and ELISA performed on bloodspot eluates are equivalent for seroepidemiological purposes.

Intestinal parasites in Iaualapiti Indians from Xingu Park, Mato Grosso, Brazil

Brine flotation and gravity sedimentation coproscopical examinations were performed in stool samples from 69 of the 147 Iaualapiti Indians of the Xingu Park, Mato Grosso State, Brazil. Intestinal parasites were present in 89.9% of the population examined. High rates of prevalence were found for some parasite species: Ancylostomidae, 82.6%; Enterobius vermicularis, 26.1%; Ascaris lumbricoides, 20.3%; and Entamoeba coli, 68.1%. Infection by Trichuris trichiura, Schistosoma mansoni, Taenia spp. and Hymenolepis nana was not detected. Helminth's prevalence in children aged one year or less was comparatively low (33.3%). Quantitative coproscopy was done in positive samples for Ascaris and Ancylostomidae and the results expressed in eggs per gram of feces (EPG). Quantitative results revealed that worm burdens are very low and overdispersed in this Indian tribe, a previously unreported fact.