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

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.

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.

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.

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.

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.

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.

[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.

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.

[Recent findings on the molecular biology of Plasmodium antigens]. / Données récentes sur la biologie moléculaire des antigènes de Plasmodium.

The cloning of several genes coding for Plasmodium antigens has allowed to determine the nucleotide sequence of these genes and to deduce the amino acid sequence of the antigens. In this review we summarize the first results concerning the CSP of P. knowlesi and P. falciparum as well as several antigens from the asexual erythrocytic stages. These antigens show the unique feature to contain one or several antigenic determinants composed of repetitive units.

Bovine papillomavirus type 1 genome in hamster sarcoma cells in vivo and in vitro: variation in the level of transcription.

The physical state and expression of the bovine papillomavirus type 1 (BPV-1) genome were analysed in two transplantable hamster sarcomas (HT1 and HT2) after a low number of transplantations, in two tumourigenic cell lines derived from the first transplant of HT2 sarcoma and another transplantable sarcoma (HT3) and in tumours obtained by grafting these cells. Blot hybridization experiments indicated the presence of multiple free copies of the whole viral genome in HT1 and HT2 tumour transplants (100 and 25 copies/cell respectively), irrespective of the number of in vivo or in vitro passages. In contrast, HT3 cells, and tumours induced by these cells, at early and late passages in vitro contained viral sequences probably integrated in the cell genome, in addition to the free viral DNA sequences. Polyadenylated viral transcripts were easily detected in HT1, HT2 and HT3 tumours obtained at early passages in vivo and in vitro, with electrophoretic mobilities corresponding to 1200 to 1400 bases (HT1, HT2 and HT3), 1750 bases (HT1) and 2500 bases (HT2). Homologous sequences of the transcripts were localized in the transforming BamHI-HindIII fragment of BPV-1 DNA, mainly in the BamHI-EcoRI fragment (0.31 to 0.602 map units). In contrast, almost no viral transcription was detected in HT2 and HT3 cells after 50 subcultures and in the tumours induced by these cells. This suggests that the tumourigenicity of the HT2 and HT3 cells is compatible with a very low level of expression of the transforming region of the BPV-1 genome.

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.

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.

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.

Messenger activity of RNA transcribed in vitro by DNA-RNA polymerase associated to vaccinia virus cores.

The coding properties of RNA transcribed in vitro by purified vaccinia cores have been investigated using Krebs ascites tumor cells, L cells, and reticulocyte lysates. Six to 10 proteins synthesized in vitro are separated on polyacrylamide gels by electrophoresis in the presence of sodium dodecyl sulfate. Their molecular weights vary from 10,000 to 44,000. The electrophoretic behavior of these proteins is similar to that of early proteins isolated from infected L cells. The tryptic peptide analysis of one of these proteins indicates similarity in amino acid sequences. These results show fidelity of both in vitro transcription and molecular weight above 44,000 are synthesized in vitro does not seem due to a competition between 12S mRNA synthesized in excess and RNA of a higher sedimentation coefficient present in a lower amount.

Geographic diversity of Plasmodium falciparum antibodies in Madagascar.

Plasma samples from 50 subjects living in three distinct regions in Madagascar (Ankazobe, Manakara, and Foulpointe) were studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis of immunoprecipitated proteins from a Plasmodium falciparum strain (FCM22/Madagascar) which had been biosynthetically labelled with 35S-methionine and maintained in long-term in-vitro culture. Four major proteins with molecular weights of 96, 100, 110, and 118 kD were precipitated by plasma from Ankazobe, whereas low molecular weight proteins (27, 40, and 47 kD) were recognised more often by plasma from Foulpointe. Plasma from Manakara immunoprecipitated proteins of intermediate molecular weight. Variations in the immunological response according to the area, or antigenic diversity among the parasitic isolates might account for these results.

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.