Oncogenic role of PDK4 in human colon cancer cells.

BACKGROUND: Cancer cells maintain high rates of glycolysis. Pyruvate dehydrogenase kinases (PDK) contribute to this phenomenon, which favours apoptosis resistance and cellular transformation. We previously reported upregulation of PDK4 in normal mucosa of colorectal cancer (CRC) patients compared with controls and in preneoplastic intestine of our mouse model. Decreased methylation of four consecutive PDK4 CpGs was observed in normal mucosa of patients. Although other members of the PDK family have been investigated for transformation potential, PDK4 has not been extensively studied. METHODS: PDK4 methylation in blood of CRC patients and controls was evaluated by pyrosequencing. PDK4 expression in human colon carcinoma cells was down-regulated by RNAi. Cellular migration and invasion, apoptosis and qRT-PCR of key genes were assessed. RESULTS: Pyrosequencing revealed decreased methylation of the same four consecutive CpGs in the blood of patients compared with controls. Cellular migration and invasion were reduced and apoptosis was increased following transient or stable inhibition of PDK4. Expression of vimentin, HIF-1 and VEGFA was reduced. CONCLUSIONS: These studies demonstrate the involvement of PDK4 in transformation. Methylation assessment of PDK4 in the blood may be useful for non-invasive CRC detection. PDK4 should be considered as a target for development of anticancer strategies and therapies.

Liver fibrosis: evaluation with diffusion-weighted magnetic resonance imaging in patients with chronic liver disease.

AIM: Liver fibrosis is often a possible evolution of chronic liver disease (CLD), with a risk of progression to cirrhosis. This study was designed to determine if the measure of apparent diffusion coefficient (ADC) is clinically accurate in the staging of fibrosis. METHODS: The study was conducted in the period 2008-2012. We recruited 84 patients with CLD. The control group included 67 patients whose laboratory, ultrasound and magnetic resonance imaging exams demonstrated liver's normal conditions. For ethical reasons, these patients did not undergo liver biopsy. Patients were examined using diffusion-weighted magnetic resonance imaging with a 1.5 Tesla magnet and with single shot echo-planar technique. Patients did undergo liver biopsy and the samples were evaluated with the Metavir score (F0-F4), Ishak score (0-6) and Brunt score (0-6). Patients were divided into three groups according to the different degree of fibrosis and the ADC was compared with U-test of Mann-Whitney. Moreover, it was used the analysis Receiver Operating Characteristic (ROC). RESULTS: A significant difference between group 1 (F0-F1) and group 3 (F3-F4) was found, with P=0.0024 and between group 2 (F2) and group 3, with P=0.027, but there was no significant difference of the ADC values in group 1 and group 2. CONCLUSION: The study showed a correlation between reduction of ADC and increasing of liver fibrosis degree. The ADC seems to be useful in staging liver fibrosis in patients with CLD, in particular to distinguish the later stages of fibrosis from early and intermediate stages.

Preferential amplification of the paternal allele of the N-myc gene in human neuroblastomas.

Genomic imprinting plays a role in influencing the parental origin of genes involved in cancer-specific rearrangements. We have analysed 22 neuroblastomas with N-myc amplification to determine the parental origin of the amplified N-myc allele and the allele that is deleted from chromosome 1p. We analysed DNA from neuroblastoma patients and their parents, using four polymorphisms for 1p and three for the N-myc amplicon. We determined that the paternal allele of N-myc was preferentially amplified (12 out of 13 cases; P = 0.002). However, the paternal allele was lost from 1p in six out of ten cases, consistent with a random distribution (P > 0.2). These results suggest that parental imprinting influences which N-myc allele is amplified in neuroblastomas, but it does not appear to affect the 1p allele that is deleted in the cases that we have examined.

A promoter mutation in the XIST gene in two unrelated families with skewed X-chromosome inactivation.

X-chromosome inactivation is the process by which a cell recognizes the presence of two copies of an X chromosome early in the development of XX embryos and chooses one to be active and one to be inactive. Although it is commonly believed that the initiation of X inactivation is random, with an equal probability (50:50) that either X chromosome will be the inactive X in a given cell, significant variation in the proportion of cells with either X inactive is observed both in mice heterozygous for alleles at the Xce locus and among normal human females in the population. Families in which multiple females demonstrate extremely skewed inactivation patterns that are otherwise quite rare in the general population are thought to reflect possible genetic influences on the X-inactivation process. Here we report a rare cytosine to guanine mutation in the XIST minimal promoter that underlies both epigenetic and functional differences between the two X chromosomes in nine females from two unrelated families. All females demonstrate preferential inactivation of the X chromosome carrying the mutation, suggesting that there is an association between alterations in the regulation of XIST expression and X-chromosome inactivation.

Perceptual characteristics of Parkinsonian speech: a comparison of the pharmacological effects of levodopa across speech and non-speech motor systems.

The purpose of this study was to: (1) define perceptual speech characteristics of idiopathic Parkinson disease (IPD) across 35 speech dimensions adapted from Darley et al. [19] and grouped under six speech-sign clusters (respiration, phonation, resonance, articulation, prosody and rate); (2) examine the effects of levodopa on the 35 perceptual speech dimensions and speech-sign clusters; and (3) to compare the relative effectiveness of levodopa on global motor functioning vs. speech production. Sixteen patients with IPD read the 'Grandfather Passage' both 'on' and 'off' levodopa. Three blinded speech-language pathologists performed perceptual speech analyses using a seven-point scale. The diagnosis of IPD was made by a movement disorders fellowship trained neurologist who applied UK Brain bank criteria and administered the Unified Parkinson Disease Rating Scale. Concordant with previous studies, the results of this experiment indicated that IPD disrupted multiple speech production subsystems, with prosody being the most severely affected domain. The perceptual dimensions that were most severely affected included: (1) sound imprecision; (2) mono-loudness; (3) mono-pitch; (4) reduced stress and (5) harsh voice. No significant differences were obtained between medicated states ('on'/'off') for any of the 35 individual speech dimensions and speech-sign clusters. Global motor function significantly improved following dopaminergic medications.

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

Natural selection and the function of genome imprinting: beyond the silenced minority.

Most hypotheses of the evolutionary origin of genome imprinting assume that the biochemical character on which natural selection has operated is the expression of the allele from only one parent at an affected locus. We propose an alternative - that natural selection has operated on differences in the chromatin structure of maternal and paternal chromosomes to facilitate pairing during meiosis and to maintain the distinction between homologues during DNA repair and recombination in both meiotic and mitotic cells. Maintenance of differences in chromatin structure in somatic cells can sometimes result in the transcription of only one allele at a locus. This pattern of transcription might be selected, in some instances, for reasons that are unrelated to the original establishment of the imprint. Differences in the chromatin structure of homologous chromosomes might facilitate pairing and recombination during meiosis, but some such differences could also result in non-random segregation of chromosomes, leading to parental-origin-dependent transmission ratio distortion. This hypothesis unites two broad classes of parental origin effects under a single selective force and identifies a single substrate through which Mendel's first and second laws might be violated.

Expiratory muscle strength training: speech production outcomes in patients with multiple sclerosis.

PURPOSE: This study investigated the effect of expiratory muscle strength training (EMST) on voice production, dysarthria, and voice-related quality-of-life issues in persons with multiple sclerosis (PwMS). It was hypothesized that PwMS would have improved voice production and reduced voice-related quality-of-life issues following EMST. PARTICIPANTS AND METHODS: Seventeen participants with MS and 14 healthy (H) controls completed 8 weeks of EMST, followed by 4 weeks of no training. Analyzed outcomes as a function of EMST were maximal expiratory pressure (MEP), sustained vowel prolongation (SVP), words per minute (WPM) measured from connected speech, and quality-of-life indices related to the presence of the dysarthria and dysphonia. RESULTS: PwMS had lower MEPs, shorter SVP, and less WPM than the controls prior to training. Following EMST, both groups had significant improvement in MEPs that stayed above baseline after training halted. EMST did not improve voice production or voice-related quality of life for PwMS. CONCLUSION: Respiratory muscle weakness is present in PwMS having mild- to moderate-level disability. EMST improved expiratory muscle strength but did not statistically change objective and subjective components of voice/speech production in PwMS.

Estudio cualitativo sobre la fragmentación y segmentación del sistema sanitario desde la experiencia de personas gestantes durante la pandemia por Covid -19 en La Plata / Qualitative study on the fragmentation and segmentation of the health system from the experience of pregnant people during the Covid-19 pandemic in La Plata

El sistema de salud argentino se ha constituido de manera compleja, caracterizándose por la segmentación y la fragmentación que dificultan la accesibilidad a los servicios de salud. Las personas gestantes constituyen una de las poblaciones de riesgo de padecer formas graves de enfermedad por coronavirus. Asimismo la Organización Panamericana de la Salud alertó sobre la interrupción de los servicios de atención de mujeres, especialmente al control prenatal y del recién nacido en la mitad de los países de las Américas. Se realizó un estudio cualitativo con el objetivo de describir y comprender las experiencias de accesibilidad al sistema de salud de personas que transitaron embarazo y/o parto durante la emergencia sanitaria en la Plata y Gran La Plata. Para ello se realizaron entrevistas semiestructuradas individuales a esta población. Los datos obtenidos fueron sometidos a un análisis de contenido temático, cuyas principales categorías de análisis fueron la segmentación y fragmentación del sistema de salud. Entre los resultados se destaca la importancia que tuvieron "las salitas" del primer nivel en el acceso a la atención de salud y el rol de las obstétricas en el intento de sortear los obstáculos que presenta la segmentación y la fragmentación del sistema sanitario. Se concluye que es menester pensar políticas para fortalecer el primer nivel de atención, la implementación de la estrategia de atención primaria de la salud en todos los niveles del sistema, al mismo tiempo que se requiere el fortalecimiento de una profesión autónoma y humanista, como lo es la obstetricia

The Argentine health system has been constituted in a complex manner, characterized by segmentation and fragmentation that hinder accessibility to health services. Pregnant women are one of the populations at risk of suffering severe forms of coronavirus disease. The Pan American Health Organization also warned about the interruption of women's health care services, especially prenatal and newborn care, in half the countries of the Americas. A qualitative study was carried out with the aim of describing and understanding the experiences of accessibility to the health system of people who experienced pregnancy and/or childbirth during the health emergency in La Plata and Gran La Plata. For this purpose, individual semi-structured interviews were conducted with this population. The data obtained were subjected to a thematic content analysis, whose main categories of analysis were the segmentation and fragmentation of the health system. Among the results, the importance of the "salitas" of the first level in the access to health care and the role of obstetricians in the attempt to overcome the obstacles presented by the segmentation and fragmentation of the health system stand out. It is concluded that it is necessary to think of policies to strengthen the first level of care, the implementation of the primary health care strategy at all levels of the system, and at the same time the strengthening of an autonomous and humanistic profession, such as midwifery, is required

Loss of heterozygosity for chromosomes 1 or 14 defines subsets of advanced neuroblastomas.

Neuroblastomas have been characterized genetically by N-myc amplification and by deletions or loss of heterozygosity (LOH) for the short arm of chromosome 1. However, recent studies have suggested deletion or allelic loss involving at least three other chromosome arms, 11q, 14q, and 17p. Therefore, we undertook an analysis of allelic loss for these respective chromosomal arms to determine the frequency and pattern of LOH as well as the correlation of these findings with other biological and clinical variables. A group of 24 pairs of normal and tumor DNAs was chosen that were representative of patients of different ages and stages. A substantial frequency of LOH (greater than or equal to 20%) was found only for 1p and 14q, whereas LOH for the other chromosome arms occurred in less than or equal to 5% of cases. On the basis of these results, we extended the analysis to a total of 59 neuroblastomas, and we found 1p LOH in 15 of the 59 cases (25%) and 14q LOH in 10 of 43 informative cases (23%). N-myc amplification was found in 15 of the 59 cases (25%). This analysis confirmed that 1p LOH and 14q LOH occurred almost exclusively in patients with advanced stages of disease. Furthermore, LOH for 1p and 14q usually occurred independent of each other, and 1p LOH frequently was associated with N-myc amplification, whereas 14q LOH was not. Thus, our results demonstrate that neuroblastomas are complex genetically and that there are at least two distinct loci for putative suppressor genes that are deleted independently in this tumor, both of which are associated with advanced stages of disease.

The Latin American Biological Dosimetry Network (LBDNet).

Biological Dosimetry is a necessary support for national radiation protection programmes and emergency response schemes. The Latin American Biological Dosimetry Network (LBDNet) was formally founded in 2007 to provide early biological dosimetry assistance in case of radiation emergencies in the Latin American Region. Here are presented the main topics considered in the foundational document of the network, which comprise: mission, partners, concept of operation, including the mechanism to request support for biological dosimetry assistance in the region, and the network capabilities. The process for network activation and the role of the coordinating laboratory during biological dosimetry emergency response is also presented. This information is preceded by historical remarks on biological dosimetry cooperation in Latin America. A summary of the main experimental and practical results already obtained by the LBDNet is also included.

Genome imprinting and carcinogenesis.

The preferential retention of paternal tumor suppressor alleles in sporadic tumors and the failure to demonstrate genetic linkage between disease predisposition and tumor suppressor loci in familial cases indicates that genome imprinting may be involved in the genesis of some pediatric cancers. A genetic model that invokes the activity of modifier loci (imprinting genes) on alleles to be modified (imprinted genes) is able to account for these data. Genome imprinting may be viewed as a special case of dominance modification, differing from other examples only in that the modification of dominance is dependent on gamete-of-origin. Data from human pediatric tumors, transgenes in the mouse and variegating position-effects in Drosophila, indicate that the net effect of modifier loci is the inactivation of alleles at affected loci. Polymorphism at the level of the modifier loci will result in different degrees of modification between individuals. With respect to tumors, the most important mechanism by which these differences are manifested is cellular mosaicism for the expression of a modified allele. Such characteristics are reminiscent of the behavior of variegating position-effects in Drosophila and the application of this paradigm to human disease phenotypes provides both a mechanism by which differential genome imprinting may be accomplished as well as genetic models that may explain the clinical association of syntenic diseases, the association between tumor progression and specific chromosomal aneuploidy and the unusual inheritance characteristics of many diseases.

Female meiosis drives karyotypic evolution in mammals.

Speciation is often accompanied by changes in chromosomal number or form even though such changes significantly reduce the fertility of hybrid intermediates. We have addressed this evolutionary paradox by expanding the principle that nonrandom segregation of chromosomes takes place whenever human or mouse females are heterozygous carriers of Robertsonian translocations, a common form of chromosome rearrangement in mammals. Our analysis of 1170 mammalian karyotypes provides strong evidence that karyotypic evolution is driven by nonrandom segregation during female meiosis. The pertinent variable in this form of meiotic drive is the presence of differing numbers of centromeres on paired homologous chromosomes. This situation is encountered in all heterozygous carriers of Robertsonian translocations. Whenever paired chromosomes have different numbers of centromeres, the inherent asymmetry of female meiosis and the polarity of the meiotic spindle dictate that the partner with the greater number of centromeres will attach preferentially to the pole that is most efficient at capturing centromeres. This mechanism explains how chromosomal variants become fixed in populations, as well as why closely related species often appear to have evolved by directional adjustment of the karyotype toward or away from a particular chromosome form. If differences in the ability of particular DNA sequences or chromosomal regions to function as centromeres are also considered, nonrandom segregation is likely to affect karyotype evolution across a very broad phylogenetic range.

The polar-lethal Ovum mutant gene maps to the distal portion of mouse chromosome 11.

Genome imprinting is the process by which identical alleles at a particular locus may be rendered functionally different depending on the sex of the parent contributing the allele. While several mutations in imprinted genes have been defined, no variants in the regulatory system that gives rise to imprinting have been described. Here we report our genetic analysis of the behavior of the interstrain, polar, embryonic-lethal phenotype known as the "DDK syndrome." We have mapped the interstrain, polar-lethal region of the genome to the distal portion of mouse chromosome 11, near the Xmv-42 locus. We propose that the lethal phenotype is not caused by a standard mutation, but by aberrant imprinting of a gene within this region.

A genetic test to determine the origin of maternal transmission ratio distortion. Meiotic drive at the mouse Om locus.

We have shown previously that the progeny of crosses between heterozygous females and C57BL/6 males show transmission ratio distortion at the Om locus on mouse chromosome 11. This result has been replicated in several independent experiments. Here we show that the distortion maps to a single locus on chromosome 11, closely linked to Om, and that gene conversion is not implicated in the origin of this phenomenon. To further investigate the origin of the transmission ratio distortion we generated a test using the well-known effect of recombination on maternal meiotic drive. The genetic test presented here discriminates between unequal segregation of alleles during meiosis and lethality, based on the analysis of genotype at both the distorted locus and the centromere of the same chromosome. We used this test to determine the cause of the transmission ratio distortion observed at the Om locus. Our results indicate that transmission ratio distortion at Om is due to unequal segregation of alleles to the polar body at the second meiotic division. Because the presence of segregation distortion at Om also depends on the genotype of the sire, our results confirm that the sperm can influence segregation of maternal chromosomes to the second polar body.

Transmission-ratio distortion through F1 females at chromosome 11 loci linked to Om in the mouse DDK syndrome.

We determined the genotypes of > 200 offspring that are survivors of matings between female reciprocal F1 hybrids (between the DDK and C57BL/6J inbred mouse strains) and C57BL/6J males at markers linked to the Ovum mutant (Om) locus on chromosome 11. In contrast to the expectations of our previous genetic model to explain the "DDK syndrome, " the genotypes of these offspring do not reflect preferential survival of individuals that receive C57BL/6J alleles from the F1 females in the region of chromosome 11 to which the Om locus has been mapped. In fact, we observe significant transmission-ratio distortion in favor of DDK alleles in this region. These results are also in contrast to the expectations of Wakasugi's genetic model for the inheritance of Om, in which he proposed equal transmission of DDK and non-DDK alleles from F1 females. We propose that the results of these experiments may be explained by reduced expression of the maternal DDK Om allele or expression of the maternal DDK Om allele in only a portion of the ova of F1 females.

Heritability of the maternal meiotic drive system linked to Om and high-resolution mapping of the Responder locus in mouse.

Matings between (C57BL/6 x DDK)F(1) females and C57BL/6 males result in a significant excess of offspring inheriting maternal DDK alleles in the central region of mouse chromosome 11 due to meiotic drive at the second meiotic division. We have shown previously that the locus subject to selection is in the vicinity of D11Mit66, a marker closely linked to the Om locus that controls the preimplantation embryo-lethal phenotype known as the "DDK syndrome." We have also shown that observation of meiotic drive in this system depends upon the genotype of the sire. Here we show that females that are heterozygous at Om retain the meiotic drive phenotype and define a 0.32-cM candidate interval for the Responder locus in this drive system. In addition, analysis of the inheritance of alleles at Om among the offspring of F(1) intercrosses indicates that the effect of the sire is determined by the sperm genotype at Om or a locus linked to Om.

Sex-of-offspring-specific transmission ratio distortion on mouse chromosome X.

During our study of the DDK syndrome, we observed sex ratio distortion in favor of males among the offspring of F(1) backcrosses between the C57BL/6 and DDK strains. We also observed significant and reproducible transmission ratio distortion in favor of the inheritance of DDK alleles at loci on chromosome X among female offspring but not among male offspring in (C57BL/6 x DDK)F(1) x C57BL/6 and (C57BL/6-Pgk1(a) x DDK)F(1) x C57BL/6 backcrosses. The observed transmission ratio distortion is maximum at DXMit210 in the central region of chromosome X and decreases progressively at proximal and distal loci, in a manner consistent with the predictions of a single distorted locus model. DXMit210 is closely linked to two distortion-controlling loci (Dcsx1 and Dcsx2) described previously in interspecific backcrosses. Our analysis suggests that the female-offspring-specific transmission ratio distortion we observe is likely to be the result of the death of embryos of particular genotypic combinations. In addition, we confirm the previous suggestion that the transmission ratio distortion observed on chromosome X in interspecific backcrosses is also the result of loss of embryos.

Male-offspring-specific, haplotype-dependent, nonrandom cosegregation of alleles at loci on two mouse chromosomes.

F(1) backcrosses involving the DDK and C57BL/6 inbred mouse strains show transmission ratio distortion at loci on two different chromosomes, 11 and X. Transmission ratio distortion on chromosome X is restricted to female offspring while that on chromosome 11 is present in offspring of both sexes. In this article we investigate whether the inheritance of alleles at loci on one chromosome is independent of inheritance of alleles on the other. A strong nonrandom association between the inheritance of alleles at loci on both chromosomes is found among male offspring, while independent assortment occurs among female offspring. We also provide evidence that the mechanism by which this phenomenon occurs involves preferential cosegregation of nonparental chromatids of both chromosomes at the second meiotic division, after the ova has been fertilized by a C57BL/6 sperm bearing a Y chromosome. These observations confirm the influence of the sperm in the segregation of chromatids during female meiosis, and indicate that a locus or loci on the Y chromosome are involved in this instance of meiotic drive.