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BACKGROUND: Increasing chronic diseases challenges the health systems of low- and middle-income countries, including Cameroon. Type 1 diabetes (T1D), among the most common chronic diseases in children, poses particular care delivery challenges. AIM: We examined social representations of patients' roles and implementation of T1D care among political decision-makers, healthcare providers and patients within families. SETTING: The study was conducted in Yaoundé, Cameroon. METHODS: Eighty-two individuals were included in the study. The authors conducted semi-structured interviews with policy makers (n = 5), healthcare professionals (n = 7) and patients 'parents (n = 20). Questionnaires were administered to paediatric patients with T1D (n = 50). The authors also observed care delivery at a referral hospital and at a T1D-focused non-governmental organisation over 15 days. Data were analysed using thematic content analysis and descriptive statistics. RESULTS: Cameroonian health policy portrays patients with T1D as passive recipients of care. While many practitioners recognised the complex social and economic determinants of adherence to T1D care, in practice interactions focused on specific biomedical issues and offered brief guidance. Cultural barriers and policy implementation challenges prevent patients and their families from being fully active participants in care. Parents and children prefer an ongoing relationship with a single clinician and interactions with other patients and families. CONCLUSION: Patients and families mobilise experience and lay knowledge to complement biomedical knowledge, but top-down policy and clinical practice limit their active engagement in T1D care.Contribution: Children with T1D and their families, policy makers, healthcare professionals, and civil society have new opportunities to contribute to person-centred care, as advocated by the Sustainable Development Goals.
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Diabetes Mellitus Tipo 1 , Femenino , Humanos , Niño , Diabetes Mellitus Tipo 1/terapia , Camerún , Atención a la Salud , Política de Salud , Enfermedad CrónicaRESUMEN
Background: Increasing chronic diseases challenges the health systems of low- and middleincome countries, including Cameroon. Type 1 diabetes (T1D), among the most common chronic diseases in children, poses particular care delivery challenges. Aim: We examined social representations of patients' roles and implementation of T1D care among political decision-makers, healthcare providers and patients within families. Setting: The study was conducted in Yaoundé, Cameroon. Methods: Eighty-two individuals were included in the study. The authors conducted semistructured interviews with policy makers (n = 5), healthcare professionals (n = 7) and patients 'parents (n = 20). Questionnaires were administered to paediatric patients with T1D (n = 50). The authors also observed care delivery at a referral hospital and at a T1D-focused nongovernmental organisation over 15 days. Data were analysed using thematic content analysis and descriptive statistics. Results: Cameroonian health policy portrays patients with T1D as passive recipients of care. While many practitioners recognised the complex social and economic determinants of adherence to T1D care, in practice interactions focused on specific biomedical issues and offered brief guidance. Cultural barriers and policy implementation challenges prevent patients and their families from being fully active participants in care. Parents and children prefer an ongoing relationship with a single clinician and interactions with other patients and families. Conclusion: Patients and families mobilise experience and lay knowledge to complement biomedical knowledge, but top-down policy and clinical practice limit their active engagement in T1D care. Contribution: Children with T1D and their families, policy makers, healthcare professionals, and civil society have new opportunities to contribute to person-centred care, as advocated by the Sustainable Development Goals.
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Calidad de la Atención de Salud , Representación Social , Camerún , Enfermedad Crónica , Diabetes Mellitus Tipo 1RESUMEN
Food safety risks are becoming a public health problem with important socioeconomic consequences for human wellbeing, especially for pregnant women and infants. In this article, we describe findings from microbiological, toxicological, and nutritional quality assessments of foods from 5 localities in Burkina Faso, with the aim to provide baseline data on the quality of food and the risks to mothers and children. Samples for assessment included food sold in markets, stores, and restaurants (eg, cereals, oilseeds, vegetables, edible oils, powdered milk, dried fish, packaged water, ready-to-eat meals). The research team selected the samples using the random route method and analyzed them at the National Public Health Laboratory in Ouagadougou between January and December 2020. A total of 443 food samples were collected, of which 101 were analyzed for microbial contamination, 360 were analyzed for the presence of toxins, and 59 were analyzed for their nutritional value. The microbiological quality of 11.88% of the food samples was unsatisfactory, and 41.50% were contaminated with aflatoxins. At least 1 pesticide residue and cyfluthrin were detected in 58.10% of samples. The most detected contaminant (cyfluthrin) was found in 79.10% of the analyzed samples. A peroxide index higher than the normal value (10 mEq/kg) was found in 3.38% of the oil samples and 76.27% of the oil samples had a vitamin A content lower than the recommended limit of 11 mg/kg. This study is the first in Burkina Faso that provides baseline data on the quality of food and potential health risks to mothers and children in Burkina Faso. Considering the level of contaminants reported in this article, it is imperative to enhance routine monitoring of foods in the country.
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Alimentos , Restaurantes , Animales , Burkina Faso , Niño , Femenino , Humanos , Lactante , EmbarazoRESUMEN
To reduce child mortality in children younger than 5 years, Burkina Faso has been offering free care to this population of children since 2016. The free care program is aligned with the Integrated Management of Childhood Illness (IMCI) guidelines. Given that the number of studies that evaluated the competence of health-care workers (HCWs) during the free care program was limited, we assessed the adherence level of HCWs to the IMCI guidelines in the context of free care. This was a secondary data analysis. Data were obtained from a cross-sectional study conducted from July to September 2020 in 40 primary health-care centers and two district hospitals in the Hauts-Bassins region in Burkina Faso. Our analysis included 419 children younger than 5 years old who were consulted according to IMCI guidelines. Data were collected through direct observation using a checklist. The overall score of adherence of HCWs to IMCI guidelines was 57.8% (95% CI, 42.6-73.0). The mean adherence score of the evaluation of danger signs was 71.9% (95% CI, 58.7-85.1). The mean adherence score of following IMCI guidelines was significantly greater in boys (54.2%) compared with girls (44.6%; P < 0.001). Adherence scores of the performance of different IMCI tasks were significantly different across HCW categories. The overall adherence of HCWs to IMCI guidelines in the context of free care was greater than the adherence reported before the implementation of free care in Burkina Faso. However, this assessment needs to be performed nationwide to capture the overall adherence of HCWs to IMCI guidelines in the context of the free care program.
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INTRODUCTION: Stroke is a major public health concern. It is a frequent pathology, 80% of which is of ischemic origin. Approximately 86% of all stroke deaths worldwide occur in low- and middle-income countries. The objective of this study was to investigate prognostic factors for in hospital lethality of stroke cases admitted in a public university hospital in Burkina Faso. METHODS: This was a retrospective cohort study with a descriptive and analytical aim on adults admitted for a stroke confirmed by a brain scan at the Sourô Sanou University Teaching Hospital (CHUSS) of Bobo-Dioulasso over the period from January 1, 2009, to December 31, 2013. RESULTS: The proportion of cases confirmed by the brain CT scan was 32% of all patients admitted for stroke in the CHUSS. The overall case fatality was 27.6%. This lethality was more pronounced in patients with hemorrhagic stroke (35.8%) compared to patients with ischemic stroke (22.4%). Median survival was higher in patients with ischemic stroke than those with hemorrhagic one (36 and 25 days, respectively) with a statistically significant difference (p value = 0.001). In multivariate analysis and hemorrhagic stroke (hazard ratio [HR]: 2.25; CI 95%: 1.41-3.61), an altered state of consciousness (HR: 1.90; CI 95%: 1.20-2.99) and the presence of central facial paralysis (HR: 1.67; CI 95%: 1.04-2.67) are factors that increased significantly the lethality. CONCLUSION: The study has identified three prognostic factors of lethality that are the hemorrhagic stroke type, the altered state of consciousness, and the central facial paralysis. Given the high case fatality, it is important to develop and implement effective prevention and management strategies adapted to the resources for the optimal control of stroke in Africa.
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Parálisis Facial , Accidente Cerebrovascular Hemorrágico , Accidente Cerebrovascular Isquémico , Adulto , Burkina Faso/epidemiología , Hospitales de Enseñanza , Humanos , Pronóstico , Estudios RetrospectivosRESUMEN
OBJECTIVE: To determine the frequency and nature of copy number variants (CNVs) identified by chromosomal microarray analysis (CMA) in a large cohort of fetuses with isolated increased nuchal translucency thickness (NT) ≥ 3.5 mm. METHODS: This was a retrospective, multicenter study, including 11 French hospitals, of data from the period between April 2012 and December 2015. In total, 720 fetuses were analyzed by rapid aneuploidy test and the fetuses identified as euploid underwent CMA. CNVs detected were evaluated for clinical significance and classified into five groups: pathogenic CNVs; benign CNVs; CNVs predisposing to neurodevelopmental disorders; variants of uncertain significance (VOUS); and CNVs not related to the phenotype (i.e. incidental findings). RESULTS: In 121 (16.8%) fetuses, an aneuploidy involving chromosome 13, 18 or 21 was detected by rapid aneuploidy test and the remaining 599 fetuses were euploid. Among these, 53 (8.8%) had a CNV detected by CMA: 16/599 (2.7%) were considered to be pathogenic, including 11/599 (1.8%) that were cryptic (not visible by karyotyping); 7/599 (1.2%) were CNVs predisposing to neurodevelopmental disorders; and 8/599 (1.3%) were VOUS. Additionally, there was one (0.2%) CNV that was unrelated to the reason for referral diagnosis (i.e. an incidental finding) and the remaining 21 were benign CNVs, without clinical consequence. Interestingly, we identified five genomic imbalances of the 1q21.1 or 15q11.2 regions known to be associated with congenital heart defects. CONCLUSION: Our study demonstrates the benefit of CMA in the etiological diagnosis of fetuses with isolated increased NT. It is worth noting that most (69%) of the detected pathogenic CNVs were cryptic. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
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Aberraciones Cromosómicas , Variaciones en el Número de Copia de ADN , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Diagnóstico Prenatal/métodos , Adolescente , Adulto , Aneuploidia , Cromosomas Humanos/genética , Femenino , Edad Gestacional , Humanos , Edad Materna , Medida de Translucencia Nucal , Embarazo , Estudios Retrospectivos , Adulto JovenRESUMEN
Microdeletion and microduplication syndromes are well-known causes of developmental delay and/or malformations of differing severity. It was recently reported that a microdeletion at the 3q13.31 locus is associated with a new syndrome combining developmental delay, postnatal overgrowth and dysmorphic features. However, the reciprocal microduplication has only been described in a few case reports displaying some clinical features of the microdeletion syndrome. Here, we report on a female infant with a 3.34 Mb microduplication of the 3q13.2q13.31 region inherited from her mother. The infant presented with severe intellectual disability, learning difficulties, intrauterine and postnatal growth retardation and skeletal particularities but no dysmorphic traits. This microduplication encompassed the previously described shortest region of overlap, which contains five genes (DRD3, ZNF80, TIGIT, MIR568 and ZBTB20). We reviewed the phenotypes described in the literature on microduplications and in the well-characterized 3q13.31 microdeletion syndrome. In agreement with the literature data, DRD3 and ZBTB20 appear to be strong candidate genes for neurodevelopmental defects and growth retardation. Lastly, we consider the putative mechanism of this rearrangement, which may involve a particular kind of nonallelic homologous recombination of human endogenous retrovirus elements.
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Deleción Cromosómica , Cromosomas Humanos Par 3 , Trastornos del Crecimiento/genética , Niño , Cromosomas Humanos Par 3/genética , Femenino , Retardo del Crecimiento Fetal/genética , Estudios de Asociación Genética , Humanos , Lactante , Recién Nacido , Discapacidad Intelectual/genética , Masculino , Proteínas del Tejido Nervioso/genética , Embarazo , Receptores de Dopamina D3/genética , Factores de Transcripción/genéticaRESUMEN
The organization and dynamics of chromatin within the interphase nucleus as chromosome territories (CTs) and the relationship with transcriptional regulation are not fully understood. We studied a natural example of chromosomal disorganization: aneuploidy due to trisomies 13, 18 and 21. We hypothesized that the presence of an extra copy of one chromosome alters the CT distribution, which perturbs transcriptional activity. We used 3D-FISH to study the position of the chromosomes of interest (18 and 21) in cultured amniocytes and chorionic villus cells from pregnancies with a normal or aneuploid karyotype. We studied the volumes of nuclei and CTs in both conditions and performed a compared transcriptome analysis. We did not observe any differences between euploid and aneuploid cells in terms of the radial and relative CT positions, suggesting that the same rules govern nuclear organization in cases of trisomy. We observed lower volumes for CTs 18 and 21. Overall genome expression profiles highlighted changes in the expression of a subset of genes in trisomic chromosomes, while the majority of transcriptional changes concerned genes located on euploid chromosomes. Our results suggest that a dosage imbalance of the genes on trisomic chromosomes is associated with a disturbance of overall genomic expression.
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Núcleo Celular/ultraestructura , Trastornos de los Cromosomas/genética , Síndrome de Down/genética , Genoma Humano , Transcriptoma , Trisomía/genética , Adulto , Amnios/metabolismo , Amnios/patología , Núcleo Celular/metabolismo , Vellosidades Coriónicas/metabolismo , Vellosidades Coriónicas/patología , Cromatina/metabolismo , Cromatina/ultraestructura , Trastornos de los Cromosomas/metabolismo , Trastornos de los Cromosomas/patología , Cromosomas Humanos Par 13/genética , Cromosomas Humanos Par 13/metabolismo , Cromosomas Humanos Par 18/genética , Cromosomas Humanos Par 18/metabolismo , Síndrome de Down/metabolismo , Síndrome de Down/patología , Femenino , Perfilación de la Expresión Génica , Edad Gestacional , Humanos , Hibridación Fluorescente in Situ , Interfase , Cariotipificación , Embarazo , Cultivo Primario de Células , Trisomía/patología , Síndrome de la Trisomía 13 , Síndrome de la Trisomía 18RESUMEN
BACKGROUND: A group A meningococcal (MenA) conjugate vaccine, PsA-TT (MenAfriVac), was introduced in Burkina Faso via mass campaigns between September and December 2010, targeting the 1- to 29-year-old population. This study describes specific antibody titers in the general population 11 months later and compares them to preintroduction data obtained during 2008 using the same protocol. METHODS: During October-November 2011, we recruited a representative sample of the population of urban Bobo-Dioulasso aged 6 months to 29 years, who underwent standardized interviews and blood draws. We assessed anti-MenA immunoglobulin G (IgG) concentrations (n = 200) and, using rabbit complement, serum bactericidal antibody (SBA) titers against 2 group A strains: reference strain F8238 (SBAref) (n = 562) and strain 3125 (SBA3125) (n = 200). RESULTS: Among the 562 participants, 481 (86%) were aged ≥23 months and had been eligible for the PsA-TT campaign. Among them, vaccine coverage was 86.3% (95% confidence interval [CI], 82.7%-89.9%). Prevalence of putatively protective antibodies among vaccine-eligible age groups was 97.3% (95% CI, 95.9%-98.7%) for SBAref titers ≥128, 83.6% (95% CI, 77.6%-89.7%) for SBA3125 ≥128, and 84.2% (95% CI, 78.7%-89.7%) for anti-MenA IgG ≥2 µg/mL. Compared to the population aged 23 months to 29 years during 2008, geometric mean titers of SBAref were 7.59-fold higher during 2011, 51.88-fold for SBA3125, and 10.56-fold for IgG. CONCLUSIONS: This study shows high seroprevalence against group A meningococci in Burkina Faso following MenAfriVac introduction. Follow-up surveys will provide evidence on the persistence of population-level immunity and the optimal vaccination strategy for long-term control of MenA meningitis in the African meningitis belt.
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Anticuerpos Antibacterianos/sangre , Vacunación Masiva , Meningitis Meningocócica/prevención & control , Vacunas Meningococicas/administración & dosificación , Vacunas Meningococicas/inmunología , Neisseria meningitidis Serogrupo A/inmunología , Adolescente , Adulto , Animales , Actividad Bactericida de la Sangre , Burkina Faso , Niño , Preescolar , Proteínas del Sistema Complemento , Femenino , Humanos , Inmunoglobulina G/sangre , Lactante , Masculino , Conejos , Estudios Seroepidemiológicos , Adulto JovenRESUMEN
Microdeletion and microduplication syndromes are well-known causes of developmental delay and/or malformations of differing severity. Although homogeneous abnormalities can now be detected relatively easily using microarray technologies, they are more difficult to detect and interpret in cases of mosaicism. Here, we report on a male infant with a mosaic de novo derivative chromosome 9, featuring a 10.2 Mb 5q35 duplication (including the NSD1 gene) and a 687 kb 9q34 deletion (including EHMT1). The infant presented developmental delay, short stature, brachy/plagiocephaly and hyperactivity. The proportion of abnormal cells was 50% in saliva (in a microarray analysis) and 25% in lymphocytes (in a FISH analysis). Despite the low-level mosaicism in lymphocytes, this imbalance appears to be responsible for a distinctive phenotype (suggesting the presence of variable clinical expression and/or major somatic mosaicism).
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Cromosomas Humanos Par 5/genética , Cromosomas Humanos Par 9/genética , Anomalías Craneofaciales/genética , Cardiopatías Congénitas/genética , Discapacidad Intelectual/genética , Mosaicismo , Fenotipo , Preescolar , Deleción Cromosómica , Anomalías Craneofaciales/diagnóstico , Eliminación de Gen , Duplicación de Gen , Cardiopatías Congénitas/diagnóstico , Histona Metiltransferasas , N-Metiltransferasa de Histona-Lisina/genética , Humanos , Discapacidad Intelectual/diagnóstico , Péptidos y Proteínas de Señalización Intracelular/genética , Masculino , Proteínas Nucleares/genéticaRESUMEN
OBJECTIVE: To establish recommendations for early recurrent miscarriages (≥3 miscarriages before 14weeks of amenorrhea). MATERIALS AND METHODS: Literature review, establishing levels of evidence and recommendations for grades of clinical practice. RESULTS: Women evaluation includes the search for a diabetes (grade A), an antiphospholipid syndrome (APS) (grade A), a thyroid dysfunction (grade A), a hyperprolactinemia (grade B), a vitamin deficiency and a hyperhomocysteinemia (grade C), a uterine abnormality (grade C), an altered ovarian reserve (grade C), and a couple chromosome analysis (grade A). For unexplained early recurrent miscarriages, treatment includes folic acid and progesterone supplementation, and a reinsurance policy in the first quarter (grade C). It is recommended to prescribe the combination of aspirin and low-molecular-weight heparin when APS (grade A), glycemic control in diabetes (grade A), L-Thyroxine in case of hypothyroidism (grade A) or the presence of thyroid antibodies (grade B), bromocriptine if hyperprolactinemia (grade B), a substitution for vitamin deficiency or hyperhomocysteinemia (grade C), sectionning a uterine septum (grade C) and treating an uterine acquired abnormality (grade C). CONCLUSION: These recommendations should improve the management of couples faced with early recurrent miscarriages.
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Aborto Habitual/diagnóstico , Aborto Habitual/terapia , Guías de Práctica Clínica como Asunto/normas , Aborto Habitual/etiología , Aborto Habitual/prevención & control , Femenino , Humanos , EmbarazoRESUMEN
Previous studies using two-dimensional gel electrophoresis have described adult and fetal isoforms of skeletal muscle myosin light chains (MLC). They have also revealed an embryo-specific light chain (LC1emb), apparently absent in most adult skeletal muscles. In order to characterize more thoroughly the MLC family, we have analyzed the MLCs from human skeletal muscle at different developmental stages using a two-dimensional electrophoresis technique with an immobilized pH gradient in the first dimension. The high resolution of this novel technique, resolving components which in isoelectric points are less than or equal to 0.01 pH, combined with sensitive silver staining, has allowed us to identify four phosphorylatable isoforms of MLC2: two slow-myosin light chains (MLC2Sa and b), two fast myosin light chains (MLC2Fa and b), and their phosphorylated counterparts: MLC2SaP and bP, MLC2FaP and bP. The following major modifications during development were observed: (i) The embryonic LC (LC1emb) persists up to at least 26 weeks of fetal life. (ii) The polymorphism of LC2 is already evident at 10 weeks of development but only the nonphosphorylated forms of LC2S and LC2F seem to be present. The LC2Fa form is predominant. As early as 26 weeks of fetal life, the 4 phosphorylated forms are detected. In the adult, LC2Fb is a minor component. (iii) LC3F (fast) is already expressed at an early embryonic stage (10 weeks).
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Electroforesis en Gel Bidimensional/métodos , Desarrollo de Músculos , Miosinas/análisis , Western Blotting , Edad Gestacional , Humanos , Concentración de Iones de Hidrógeno , Peso Molecular , Músculos/análisis , Músculos/embriología , Fosforilación , Polimorfismo GenéticoRESUMEN
L6 myoblasts in vitro accomplish the process of terminal differentiation from dividing mononucleated cells to quiescent plurinucleated myotubes, synthesizing muscle-specific proteins. They have been tested, using paraformaldehyde and acetic acid fixations and immunocytochemical techniques, for the presence of Z-DNA at different stages: namely after 3, 5 and 8-9 days of culture. The nuclei of the actively dividing 3-day myoblasts were strongly Z-DNA and B-DNA-positive. The inhibition of replication by araC did not diminish the reaction. In the myotubes, the nuclei became Z-DNA-negative but were still B-DNA-positive. In contrast, the nuclei of a non-fusing alpha-amanitin-resistant mutant (Ama102) stayed Z-DNA-positive. These results tend to show that during the process of terminal differentiation Z-DNA either becomes less accessible or is present in undetectable amounts. In circular DNAs, it has been shown that the presence of Z-DNA depends on their negative supercoiling. In addition, the presence of closed superhelical loops of nuclear DNA has been demonstrated in several mammalian cell types; moreover, the density of DNA topological turns in these loops varies during cellular differentiation and malignant transformation. The relationship between these results and ours is discussed.
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ADN/metabolismo , Músculos/citología , Animales , Diferenciación Celular , Línea Celular , Núcleo Celular/metabolismo , Citarabina/farmacología , ADN/inmunología , Fijadores , Técnicas Inmunológicas , RatasRESUMEN
Correlations between cell morphology and the expression of specific proteins (crystallins) have been investigated. Two different culture conditions have been chosen which keep bovine epithelial lens cells (BEL cells) in a monolayer of homogeneous epithelioid cells: (1) bovine retinal extract (EDGF) supplemented medium; (2) extracellular matrix (ECM) provided by corneal endothelial cells in standard medium has been compared to previous results obtained with BEL cells cultivated on plastic (Simonneau et al., 1983). Variations of the cell shape had no effect upon crystallin synthesis.
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Cristalinas/biosíntesis , Cristalino/citología , Animales , Bovinos , Diferenciación Celular , Células Cultivadas , Medios de Cultivo , Células Epiteliales , Matriz Extracelular , Cristalino/metabolismoRESUMEN
Maintenance of the state of differentiation in serially cultured bovine epithelial lens cells has been investigated. The radioactive labelled soluble proteins were studied by gel filtration and gel electrophoresis. 1. In the lens epithelium on its capsule, preferential synthesis of alpha B2 vs alpha A2 crystallin subunits and synthesis of beta-crystallins (mainly beta Bp) were observed. 2. Epithelial lens cells cultured on plastic Petri dishes for up to 35 divisions still synthesized alpha B2 and beta Bp, but no longer alpha A2. Conversely, the same cells injected into nude mice synthesized alpha B and alpha A, but no beta-crystallin could be detected. 3. The ratio of non-crystallin proteins to crystallin polypeptides increased drastically with the number of cell divisions. Among these proteins, both Mr 45 000 and Mr 57 000 proteins are probably constituents of the water-soluble cytoskeletal proteins, respectively actin and vimentin. A Mr 17 000 polypeptide was observed and its relationship with a metabolic product of alpha-crystallin is proposed. 4. The polymerization process of crystallin polypeptides in these cells was studied and compared with crystallin aggregates found in the lens. Newly synthesized alpha crystallins were readily involved in high molecular aggregates. This process does not seem to require alpha A, since only alpha B was detected. Interestingly, non-crystallin-soluble proteins form the bulk of proteins found in high molecular weight (HMW) polymers. The time course of crystallin aggregate formation, in long-term culture cells, seems to be different for alpha- vs beta-polypeptides. These results allowed us to conclude that bovine epithelial lens cells in vitro, although they do not undergo terminal differentiation into fibers, are not dedifferentiated, since they still express specific features of the epithelium in situ.
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Diferenciación Celular , Cristalinas/biosíntesis , Cristalino/citología , Biosíntesis de Proteínas , Animales , Bovinos , División Celular , Células Cultivadas , Células Epiteliales , Inmunodifusión , Cristalino/metabolismo , Sustancias Macromoleculares , Peso MolecularRESUMEN
The temporal and spatial sequence of nuclear disappearance during the terminal differentiation of lens fiber cells could be due to an impairment of the DNA repair pathways or to the appearance of an active DNA degradation process. The results presented here favor the second hypothesis. A single-stranded DNA nuclease activity and a double-stranded DNA nuclease activity have been found in chick embryo fiber cells. Moreover, there is a good correspondence between the variations of the nuclease activity and the stages of differentiation of the different samples analyzed.
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Desoxirribonucleasas/metabolismo , Cristalino/enzimología , Animales , Embrión de Pollo , ADN de Cadena Simple/metabolismo , Electroforesis en Gel de AgarAsunto(s)
Cámara Anterior/lesiones , Coroides/lesiones , Presión Intraocular , Adulto , Contusiones/complicaciones , Humanos , Iris/cirugía , MasculinoRESUMEN
"Histone synthesis was compared in epithelial lens cells during exponential growth and in the stationary phase brought by contact inhibition. Double labelling experiments with 3H-lysine and 14C-lysine show a net turnover of histone H1 independent of DNA replication. The nucleosome core histones seem to turn over also, but much more slowly than H1".