Representaciones sociales sobre lactancia materna y alimentación complementaria en familias que se atienden en un hospital público de la provincia de Buenos Aires / Representations social about breastfeeding and food complementary in families that they care in a hospital public of the province from Buenos Aires

La lactancia materna y una alimentación complementaria adecuada en los primeros dos años del niño son fundamentales para lograr un mejor crecimiento y desarrollo, estando dichas prácticas moldeadas por las representaciones sociales de cada familia. El objetivo de este trabajo fue conocer las representaciones sociales sobre lactancia materna, la alimentación complementaria y sobre el sistema de salud en relación a las prácticas de alimentación de familias que realizaron el control de salud de sus niños en un hospital público de la Provincia de Buenos Aires. Metodología: Se utilizó un diseño cualitativo, a través de dos grupos focales con familiares responsables de la alimentación de niños que realizaban sus controles en los consultorios pediátricos del Observatorio de salud del IDIP durante los meses noviembre 2022 a marzo 2023. A partir del análisis se llegó a la construcción de distintas subcategorías de representaciones sociales: valores, creencias, aprendizajes, normas y mitos. El proyecto fue aprobado por el Comité de Ética Institucional. Resultados: Se encontró una valoración de la lactancia materna como práctica que refuerza el vínculo con el lactante y como el mejor alimento para el niño. Los factores socioeconómicos y el tiempo se identificaron como limitantes para lograr una alimentación complementaria saludable. El sistema de salud se presentó como un constante generador de información sobre las formas de inicio y mantenimiento de estas prácticas de alimentación. Conclusiones: Es fundamental conocer las representaciones sociales que moldean las prácticas de lactancia materna y alimentación complementaria de cada comunidad para diseñar acciones desde el sistema de salud enfocadas en la prevención de la malnutrición infantil, y en consecuencia, las enfermedades crónicas no transmisibles, promoviendo una nutrición sana y un óptimo desarrollo físico y mental

Breastfeeding and adequate complementary feeding in the first two years of the child are essential to achieve better growth and development, these practices being shaped by the social representations of each family. We sought to know the social representations about breastfeeding and complementary feeding in families that carried out the health control of their children in a public hospital in the Province of Buenos Aires. Methodology: A qualitative design was used, through two focus groups with relatives responsible for feeding children who carried out their controls in the pediatric clinics of the IDIP Health Observatory during the months of November 2022 to March 2023. From the analysis, the construction of different subcategories of social representations was reached: values, beliefs, learning, norms and myths. The project was approved by the institutional ethics committee. Results: An assessment of breastfeeding was found as a practice that reinforces the bond with the infant and as the best food for the child. Socioeconomic factors and time were identified as limiting to achieve a healthy complementary diet. The health system was presented as a constant generator of information on the ways to start and maintain these feeding practices. Conclusions: It is essential to know the social representations that shape the practices of breastfeeding and complementary feeding in each community, to design actions from the health system focused on the prevention of child malnutrition, and consequently, chronic non-communicable diseases, promoting a healthy nutrition and optimal physical and mental development

Antiplasmodial activity of acetogenins and inhibitory effect on Plasmodium falciparum adenylate translocase.

Three Annonaceous acetogenins exhibited in vitro antimalarial activities on a chloroquine-resistant Plasmodium falciparum strain, with IC50s ranging from 5 to 10 microM. Structure-activity relationships showed that maximal antimalarial activity occurred in the presence of at least one tetrahydrofuran moiety and a synergistic action with chloroquine was observed. These acetogenins partially inhibited the P. falciparum adenylate translocase.

Development and optimization of polymerase chain reaction-based malaria diagnostic methods and their comparison with quantitative buffy coat assay.

Polymerase chain reaction (PCR)-based assays targeting the small-subunit rRNA were developed and evaluated, allowing for the simultaneous diagnosis of Plasmodium falciparum and Plasmodium vivax DNA in human blood samples. The PCR methods and quantitative buffy coat (QBC) were compared in 402 patients. The heminested PCR method showed a sensitivity of 97.4%, which was superior to the sensitivity of the QBC method (91.7%, P < 0.05), to simple PCR (84.6%, P < 0.001), and to PCR with digoxigenin labeling (PCR-DIG) (88.5%, P < 0.001). The PCR-DIG and QBC analyses were more sensitive than simple PCR (P < 0.003 and P < 0.05, respectively). There was no significant difference between the sensitivities of the QBC assay and the PCR-DIG assay. The specificity for the 3 PCR-based methods was 100%, superior to the specificity calculated for the QBC assay (88.95%, P < 0.009). The frequency of a positive result in groups from endemic areas but without detectable parasitemia increased, in order, from simple PCR, QBC test, PCR-DIG, to heminested PCR. An association between a positive PCR result and a history of malaria was also found. Taken together, these data suggest that this technology could be further developed to screen people with oligoparasitemia and to monitor malaria treatment.

Antimalarial activity of new gossypol derivatives.

Gossypol, a disesquiterpene extracted from cotton seeds, is known to inhibit strongly the Plasmodium falciparum lactate dehydrogenase, but its high toxicity has stopped any antimalarial drug development. A series of Schiffs bases was synthesized from gossypol by modification of the aldehyde groups responsible for its toxicity. A total of 13 compounds showing low cytotoxicity were then selected and were compared with gossypol for activity against 2 chloroquine-resistant strains of P. falciparum (PFB, FCB1). These in vitro activities were evaluated using an isotope-based drug-susceptibility semiautomated microdilution test followed by determination of IC50 values (50% inhibitory concentration). In all, 12 of the 13 compounds tested were active; 3 of them displayed antimalarial activity comparable with that of gossypol itself.

Development of a Plasmodium PCR for monitoring efficacy of antimalarial treatment.

We report in this work a highly sensitive and nonradioactive PCR method for the detection of the four species of parasite causing human malaria. Plasmodium-specific primers corresponding to the small-subunit rRNA genes of the malaria parasite were used, and a 291-bp fragment was amplified. Our results showed a high specificity for the four human Plasmodium species, and we were able to detect one parasite in 50 microl of whole blood. The responses of 12 patients infected with Plasmodium falciparum to antimalarial therapy were monitored by PCR diagnosis and examination of thick blood film for at least 20 min by an experienced microscopist. For one patient this study allowed early diagnosis of therapeutic failure, confirmed 7 days later by examination of the thick blood film. A total of 134 samples were examined; 94 were positive by PCR, and among these 68 were positive by thick blood film examination. The sensitivity of the thick blood film was 72.3% compared to PCR and 60.7% compared to dot blot hybridization.

Binding of HIV-1 to RBCs involves the Duffy antigen receptors for chemokines (DARC).

The Duffy Antigen Receptor for Chemokines (DARC) belongs to a family of erythrocyte chemokine receptors that bind C-X-C and C-C chemokines such as interleukin 8 (IL-8), monocyte chemoattractant protein 1 (MCP-1) and regulated-on-activation, normal T cell-expressed and -secreted (RANTES), but not macrophage inflammatory protein 1 alpha (MIP-1 alpha) or MIP-1 beta. DARC has also been identified to a receptor for malaria parasites Plasmodium vivax and Plasmodium knowlesi. In the present study, we show that HIV-1 binds to RBCs from Caucasian individuals via DARC making RBCs able to transmit HIV to peripheral blood mononuclear cells (PBMCs). Furthermore, binding of HIV-1 particles to RBCs is inhibited by treating these cells with recombinant RANTES, but not with recombinant MIP-1 alpha prior to their incubation with HIV-1. This finding suggests that RBCs may function as a reservoir for HIV-1 or as a receptor for the entry of HIV-1 into CD4-cell subsets as well as neurons or endothelial cells.

Identification of a family of Rab G-proteins in Plasmodium falciparum and a detailed characterisation of pfrab6.

As a first step towards developing a set of compartment-specific probes for studying protein trafficking in the malaria-infected erythrocyte, we describe here a family of Plasmodium falciparum Rab proteins. We characterise in detail P. falciparum Rab6 (PfRab6) a marker which in other cells is specific for the Golgi/trans Golgi network. Although PfRab6 mRNA is expressed throughout the intraerythrocytic cycle, maximal expression occurs at the trophozoite stage. Immunofluorescence microscopy shows that the distribution of PfRab6 changes during the final stages of parasite maturation, coalescing into multiple foci, each of which is associated with the nucleus of a forming daughter parasite.

Small GTP-binding proteins in Plasmodium falciparum.

During its erythrocytic life cycle Plasmodium falciparum exchanges compounds with host cells through phagocytosis and exocytosis. In eucaryotic cells, small GTP-binding proteins of the Ras superfamily appear to be involved in different steps of membrane trafficking and in intracellular signals. In this paper, we investigate the Rab4, Rab6 and Ras-related proteins in P falciparum infected red cells. We report that P falciparum Rab and Ras-related proteins could be distinguished from their counterparts by iso-electrofocusing and immunoblotting. The localization of P falciparum Rab 4 and Rab 6 was studied by immunogold electron microscopy on ultrathin frozen sections of infected red blood cells. Rab4 parasite-related protein was found associated with the membranes of early endosome-like structures near the parasite plasma membrane. Rab6-related protein was associated with the Golgi/trans Golgi network, as already suggested by immunofluorescence microscopy studies and Ras-related protein was cytoplasmic and plasma membrane-associated. These results are in accordance with their mammalian counterparts and support the implication of Rab-related proteins in vesicular trafficking in Plasmodium.

Molecular characterisation of the ADP/ATP-transporter cDNA from the human malaria parasite Plasmodium falciparum.

We have isolated a cDNA sequence encoding the ADP/ATP transporter in Plasmodium falciparum. The sequence analysis revealed an open reading frame encoding 301 amino acids and showed significant similarities to known eukaryotic translocases such as that of Chlorella (up to 67.2% identity) and the human transporter (61.2%). RNA blot analysis showed the presence of mRNA encoding for a 33.7-kDa ADP/ATP transporter. During the cell cycle of the parasite the expression levels of the transcripts fluctuate. The mitochondrial ADP/ATP transporter could play a role in energy metabolism of P. falciparum and makes this transporter an excellent target for chemotherapy.

An alternative to DNA extraction for the diagnosis of Pneumocystis carinii pneumonia by polymerase chain reaction using a new oligonucleotide probe.

We have used new specific primers and probe in a polymerase chain reaction (PCR) followed by Southern blot assays to detect Pneumocystis carinii in human bronchoalveolar lavage samples obtained from HIV-infected patients with pulmonary symptoms. To facilitate the procedure we developed a filtration technique without DNA extraction yielding a high sensitivity (18/18 positive results). The high specificity of the technique was shown by testing immunosuppressed patients without P. carinii pneumonia.

Plasmodium falciparum: differential sensitivity in vitro to E-64 (cysteine protease inhibitor) and Pepstatin A (aspartyl protease inhibitor).

We investigated the effect of a cysteine proteinase inhibitor (E-64) and an aspartyl proteinase inhibitor (Pepstatin A) on asexual erythrocytic stages of Plasmodium falciparum in culture. These two protease inhibitors showed different patterns of activity. E-64 acted preferentially against trophozoite and schizont stages. After 48 h incubation at high concentrations of E-64 (28, 140, 280 microM), growth was totally abolished and the parasites presented characteristic enlarged food vacuoles. Morphological alterations were also seen after shorter incubation periods (6 h at 28 microM) or 12 h at the inhibitory concentration 50% (12 microM), but an additional culture period (24 h) in inhibitor-free medium allowed normal parasite development, demonstrating a parasitostatic effect. E-64 acts on parasite multiplication; the normal merozoite maturation was altered and the normal reinvasion process partially impaired. Pepstatin A used at the inhibitory concentration 50% (4 microM) killed the parasites before trophozoite development and had a major effect on schizonts maturation. No altered parasite development occurred during an additional culture period without Pepstatin A, demonstrating a parasiticidal effect. E-64 and Pepstatin A used in combination inhibit the parasite growth with a strong synergistic effect.

Plasmodium falciparum: isolation and characterization of a 55-kDa protease with a cathepsin D-like activity from P. falciparum.

Native electrophoresis followed by imprint digest method using hemoglobin as substrate allowed the detection of parasite hemoglobinase activity at acidic pH (3.9 to 5). This protease was inhibited specifically by pepstatin A and insensitive to other protease inhibitors. The molecular weight determination using modified SDS-PAGE followed by imprint digest method, demonstrated a single area of activity at 55-58 kDa, similar to cathepsin D characterized in eucaryotic cells. The parasitic origin has been shown by radiolabeling experiments with [35S]-methionine. The 55-kDa protein was immunoprecipitated by a rabbit anti-cathepsin D serum.

[Evaluation of malarial indices in the forest region of Djoum (southern Cameroon)]. / Evaluation des indices paludométriques dans la région forestière de Djoum (Sud Cameroun).

The authors report the results of a sample survey carried out in Djoum to evaluate the main malarial indexes among 0-15 years old children. These investigations suggest that malaria is hyperendemic in this forestry area, at the end of the dry season.

Efficacy of a 3-day oral regimen of a quinine-quinidine-cinchonine association (Quinimax) for treatment of falciparum malaria in Madagascar.

In the search for an effective, safe and field-adapted alternative to chloroquine for therapy of chloroquine-resistant Plasmodium falciparum infections in Africa, a 3-d oral regimen of Quinimax (an association of quinine, quinidine and cinchonine) was evaluated in 35 individuals with P. falciparum in Madagascar, an area with chloroquine resistance. 63% of the parasite strains isolated were resistant in vitro to chloroquine, and 59% of the infections were present despite previous chloroquine intake. Three daily oral doses of 10 mg/kg Quinimax for 3 d cleared parasitaemia and improved clinical status in all subjects. Mean parasite and fever clearance times were 51.7 and 37.4 h, respectively. All patients were aparasitaemic at the end of the 7-d follow-up. When formulating therapy guidelines, the 3-d Quinimax regimen should be considered as a valuable alternative to chloroquine for treating falciparum malaria in African areas with clinical resistance to chloroquine.

Plasmodium falciparum exoprotein stimulation of human T-lymphocytes unsensitized to malaria.

The effects of Plasmodium falciparum proteins released in asexual blood stage culture supernatants on human T-lymphocytes from malaria non-immune donors were examined. Supernatants from several plasmodial strains stimulated both CD+4 and CD+8 T-lymphocytes to proliferate and secrete interferon gamma in vitro. Active moieties were predominantly released during the final stages of the parasite cycle. They were enriched by gel filtration and were further purified by anion-exchange and Superose 12 column fast protein liquid chromatography. Three active fractions of apparent 250, 70 and 18 kilodaltons were identified. The parasitic origin of the predominant 70-kilodaltons protein(s) was shown by biosynthesis experiments with radioactive amino acid precursors and was also demonstrated by in vitro translation of parasitic mRNA species. Interestingly, antibodies to the 70-kilodalton exoprotein(s) also reacted to a schizont protein of similar molecular weight.

The polymorphic 11.1 locus of Plasmodium falciparum.

Clone pPF11.1 encodes a Plasmodium falciparum antigen expressed during the intraerythrocytic cycle and containing tandem repeats of a 9 amino acid unit. We report here an analysis of the genomic region specific for 11.1, which extends over 30 kb. It contains two blocks of repeats, spanning 13 kb and 9 kb. The restriction map suggests that the locus may result from a gene duplication. The 11.1 region is present in all P. falciparum strains examined so far. Southern analysis of 8 distinct isolates indicates that the locus is highly polymorphic. Thus the pPF11.1 repeats constitute a sensitive and discriminating probe to type P. falciparum strains.