987 resultados para small-delay defects


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mestrado em Finanças

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introducción: Las Lipofuscinosis Ceroideas Neuronales (LCNs) son un grupo de patologías neurodegenerativas hereditarias de atesoramiento lisosomal (PALs) caracterizadas por el almacenamiento en los lisosomas de materiales complejos pobremente reconocidos. Su curso es muy severo con desenlace fatal, habiendo sido definidos diversos tipos sobre la base del estudio de los fenotipos clínicos, enzimáticos, morfológicos y las mutaciones. Su incidencia es de 1:12.500 nacimientos vivos a nivel mundial. Las intervenciones farmacológicas con moléculas pequeñas han sido exitosas para algunas PALs; sin embargo, debido a que para cada una de las moléculas ha sido asumido un mecanismo de acción, la efectividad puede estar limitada a uno o a pocos desórdenes y no beneficiar a otros. Se han comprobado efectos diversos de una serie de moléculas tales como Miglustat, Chaperonas moleculares diseñadas, Clenbuterol, N-acetilcisteina (Mucomyst), Cisteamina, Gentamicina y PTC124. Los tratamientos farmacológicos/ con moléculas pequeñas podrían resultar exitosos para las LCNs, mereciendo consideración desarrollar terapias para estos desórdenesObjetivo generalo Investigar en un tipo de patologías del sistema nervioso central, las Lipofuscinosis Ceroideas Neuronales, el enfoque terapéutico-farmacológico con pequeñas moléculas aplicado a otras patologías hereditarias.Objetivos específicoso Desarrollar un prototipo de cultivo de fibroblastos de pacientes a nivel hospitalario en Córdoba y mantener cultivos de fibroblastos de pacientes afectados de una LCN de genotipo CLN2, con mutaciones conocidas. o Enriquecer los cultivos con fármacos/ moléculas pequeñas probadas en otras PALs.o Averiguar si se produce incremento de actividad enzimática de la Tripeptidil Peptidasa-I (TPP-I) lisosomal.Materiales y Métodos: cultivo de fibroblastos de pacientes con el agregado de fármacos/pequeñas moléculas. Los donantes serán diagnosticados en CEMECO a través de una estrategia sistematizada para el reconocimiento de las LCNs y se identificarán las mutaciones en el gen CLN2 causales de enfermedad. Se averiguará la actividad enzimática de TPP-I y se marcará la enzima con anticuerpos específicos en corridas electroforéticas por western blot. Resultados esperados: incrementos en la actividad enzimática de TPP-I en los cultivos celulares con agregado de fármacos/ pequeñas moléculas con respecto a los controles. Importancia del proyecto: se trata de una investigación traduccional (traslational research) en la cual la clínica y los servicios a pacientes se vinculan con la investigación científica, desde una perspectiva de integración. Se desarrolla en un Hospital Público, el Hospital de Niños de la Provincia de Córdoba, asiento del Centro de Estudio de las Metabolopatías Congénitas-CEMECO. Se beneficiarán los pacientes, dado que impactará sobre la calidad de los servicios hospitalarios al suministrar diagnósticos bajo los estándares internacionales, en estrecha vinculación con centros referenciales del exterior. Se obtendrán para los genes de las LCNs los datos del espectro de mutaciones y polimorfismos presentes en la región y se aportarán datos sobre posibilidades de las terapias farmacológicas en relación a cada una de las mutaciones.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Las Enfermedades de Atesoramiento de Glucógeno (EAGs) también llamadas Glucogenosis comprenden un grupo de entidades causadas por una deficiencia enzimática específica relacionada con la vía de síntesis o degradación de esta macromolécula. La heterogeneidad fenotípica de los pacientes afectados dificulta la identificación de las diferentes variantes de EAG y por ende la correcta definición nosológica. En el Centro de Estudio de las Metabolopatías Congénitas, CEMECO, se fueron definiendo los diferentes tipos de Glucogenosis a través de una estrategia multidisciplinaria que integra distintos niveles de investigación clínica y complementaria, laboratorio metabólico especializado, enzimático, histomorfológico y de análisis molecular. Sin embargo, en algunos enfermos, entre los que se encuentran aquellos con defectos en el sistema de la fosforilasa hepática (EAG-VI y EAG-IX), la exacta definición nosológica aún no está resulta. La EAG-VI se refiere a un defecto en la fosforilasa hepática, enzima codificada por el gen PYGL, mientras que la EAG-IX es causada por un defecto genético en una de las subunidades de la fosforilasa b quinasa hepática codicadas por los genes PHKA2, PHKB y PHKG2, respectivamente. El objetivo del presente trabajo es propender a la definición nosológica de pacientes con defectos en el sistema de la fosforilasa mediante una estrategia de análisis molecular investigando los genes PYGL, PHKA2, PHKB y PHKG2. Los pacientes incluidos en este estudio deberán ser compatibles de padecer una EAG-VI o EAG-IX sobre la base de síntomas clínicos y hallazgos bioquímicos. La metodología incluirá la determinación de la enzima fosforilasa b quinasa en glóbulos rojos y dentro del análisis molecular la extracción de DNA genómico a partir de sangre entera para la amplificación por PCR de los exones más las uniones exon/intron de los genes PHKG2 y PYGL y la extracción de RNA total y obtención de cDNA para posterior amplificación de los cDNA PHKA2 y PHKB. Todos los fragmentos amplificados serán sometidos a análisis de secuencia de nucleótidos. Resultados esperados. Este trabajo, primero en Argentina, permitirá establecer las bases moleculares de los defectos del sistema de la fosforilasa hepática (EAG-VI y EAG-IX). El poder lograr este nivel de investigación traerá aparejado, una oferta integrativa en el vasto capítulo de las glucogenosis hepáticas, con extraordinaria significación en la práctica asistencial para el manejo, pronóstico y correspondiente asesoramiento genético. Hepatic glycogen storage diseases (GSDs) are a group of disorders produced by a deficiency in a specific protein involved in the metabolism of glycogen causing different types of GSDs. Phenotypic heterogeneity of affected patients difficult to identify the different GSD variants and therefore the correct definition of the disease. In the “Centro de Estudio de las Metabolopatías Congénitas”, CEMECO, were defined the different GSD types by a protocol which included complex gradual levels of clinical, biochemical, enzymatic and morphological investigation. However, in some patients, like those one with defects in the hepatic phosphorylase system (GSD-VI and GSD-IX) the exact definition of the disease has not yet been resolved. The GSD-VI is produced by a defect in the PYGL gen that encode the liver phosphorylase, while the GSD-IX is caused by a genetic defect in one of the Phosphorylase b kinase subunits, encoded by the PHKA2, PHKB and PHKG2 genes, respectively. The aim of the present study is to define the phosphorylase system defects in argentinian patients through a molecular strategy that involve the investigation of PYGL, PHKA2, PHKB and PHKG2 genes. Patients included in the present study must be compatible with a GSD-VI or GSD-IX on the bases of clinical symptoms and biochemical findings. The phosphorylase b kinase activity will be assay on in blood red cells. The molecular study will include genomic DNA extraction for the amplification of PHKG2 and PYGL genes and the total RNA extraction for amplification of the PHKA2 and PHKB cDNA by PCR. All PCR-amplified fragments will be subjected to direct nucleotide sequencing. This work, first in Argentina, will make possible to establish the molecular basis of the defects on the hepatic phosphorylase system (GSD-VI and GSD IX). To achieve this level of research will entail advance in the study of the hepatic glycogen storage disease, with extraordinary significance in the treatment, prognosis and the genetic counselling.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

წიგნში წარმოდგენილია საქართველოში ზოგიერთი ოპტიკურად აქტიური მცირე ატმოსფერული მინარევის მრავალწლიური კვლევის შედეგები. წარმოდგენილია მონაცემები C02, CHx, S02 და აეროზოლების ანთროპოგენური ემისიების შესახებ. დაწვრილებითაა შესწავლილი აეროზოლების თვლადი კონცენტრაციის ვერტიკალური განაწილება ტროპოსფეროში საქართველოს სხვადასხვა რეგიონისთვის. ჩატარებულია ოზონის საერთო რაოდენობის, ატმოსფერული აეროზოლების ოპტიკური სიმკვრის და სხვა ნაერთების გრძელვადიანი ვარიაცების დეტალური ანალიზი. წარმოდგენილია ზოგიერთი ნაერთის გავლენის თეორიული შეფასება საქართველოში მზის პირდაპირი და გაბნეული რადიაციის რეჟიმზე.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background:Congenital heart defects (CHD) are the most prevalent group of structural abnormalities at birth and one of the main causes of infant morbidity and mortality. Studies have shown a contribution of the copy number variation in the genesis of cardiac malformations.Objectives:Investigate gene copy number variation (CNV) in children with conotruncal heart defect.Methods:Multiplex ligation-dependent probe amplification (MLPA) was performed in 39 patients with conotruncal heart defect. Clinical and laboratory assessments were conducted in all patients. The parents of the probands who presented abnormal findings were also investigated.Results:Gene copy number variation was detected in 7/39 patients: 22q11.2 deletion, 22q11.2 duplication, 15q11.2 duplication, 20p12.2 duplication, 19p deletion, 15q and 8p23.2 duplication with 10p12.31 duplication. The clinical characteristics were consistent with those reported in the literature associated with the encountered microdeletion/microduplication. None of these changes was inherited from the parents.Conclusions:Our results demonstrate that the technique of MLPA is useful in the investigation of microdeletions and microduplications in conotruncal congenital heart defects. Early diagnosis of the copy number variation in patients with congenital heart defect assists in the prevention of morbidity and decreased mortality in these patients.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

AbstractIn children with structural congenital heart disease (CHD), the effects of chronic ventricular pacing on diastolic function are not well known. On the other hand, the beneficial effect of septal pacing over apical pacing is still controversial.The aim of this study was to evaluate the influence of different right ventricular (RV) pacing site on left ventricular (LV) diastolic function in children with cardiac defects.Twenty-nine pediatric patients with complete atrioventricular block (CAVB) and CHD undergoing permanent pacing were prospectively studied. Pacing sites were RV apex (n = 16) and RV septum (n = 13). Echocardiographic assessment was performed before pacemaker implantation and after it, during a mean follow‑up of 4.9 years.Compared to RV septum, transmitral E-wave was significantly affected in RV apical pacing (95.38 ± 9.19 vs 83 ± 18.75, p = 0.038). Likewise, parameters at the lateral annular tissue Doppler imaging (TDI) were significantly affected in children paced at the RV apex. The E´ wave correlated inversely with TDI lateral myocardial performance index (Tei index) (R2= 0.9849, p ≤ 0.001). RV apex pacing (Odds ratio, 0.648; confidence interval, 0.067-0.652; p = 0.003) and TDI lateral Tei index (Odds ratio, 31.21; confidence interval, 54.6-177.4; p = 0.025) predicted significantly decreased LV diastolic function.Of the two sites studied, RV septum prevents pacing-induced reduction of LV diastolic function.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

AbstractBackground:Prone imaging has been demonstrated to minimize diaphragmatic and breast tissue attenuation.Objectives:To determine the role of prone imaging on the reduction of unnecessary rest perfusion studies and coronary angiographies performed, thus decreasing investigation time and radiation exposure.Methods:We examined 139 patients, 120 with an inferior wall and 19 with an anterior wall perfusion defect that might represented attenuation artifact. Post-stress images were acquired in both the supine and prone position. Coronary angiography was used as the “gold standard” for evaluating coronary artery patency. The study was terminated and rest imaging was obviated in the presence of complete improvement of the defect in the prone position. Quantitative interpretation was performed. Results were compared with clinical data and coronary angiographic findings.Results:Prone acquisition correctly revealed defect improvement in 89 patients (89/120) with inferior wall and 12 patients (12/19) with anterior wall attenuation artifact. Quantitative analysis demonstrated statistically significant difference in the mean summed stress scores (SSS) of supine and mean SSS of prone studies in patients with disappearing inferior wall defect in the prone position and patent right coronary artery (true negative results). The mean difference between SSS in supine and in prone position was higher with disappearing than with remaining defects.Conclusion:Technetium-99m (Tc-99m) tetrofosmin myocardial perfusion imaging with the patient in the prone position overcomes soft tissue attenuation; moreover it provides an inexpensive, accurate approach to limit the number of unnecessary rest perfusion studies and coronary angiographies performed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The experiments reported were started as early as 1933, when indications were found in class material that the factor for small pollen, spl, causes not only differences in the size of pollen grains and in the growth of pollen tubes, but also a competition between megaspores, as first observed by RENNER (1921) in Oenothera. Dr. P. C. MANGELSDORF, who had kindly furnished the original seeds, was informed and the final publication delayed untill his publication in 1940. A further delay was caused by other circunstances. The main reason for the differences of the results obtained by SINGLETON and MANGELSDORF (1940) and those reported here, seems to be the way the material was analysed. I applied methods of a detailed statistical analysis, while MANGELSDORF and SINGLETON analysed pooled data. 1) The data obtained on pollen tube competition indicate .that there is about 3-4% of crossing-over between the su and sp factors in chromosome IV. The elimination is not always complete, but from 0 to 10% of the sp pollen tubes may function, instead of the 50% expected without elimination. These results are, as a whole, in accordance with SINGLETON and MANGELSDORF's data. 2) Female elimination is weaker and transmission determined as between 16 to 49,5%, instead of 50% without competition, the values being calculated by a special formula. 3) The variability of female elimination is partially genotypical, partially phenotypical. The former was shown by the difference in the behavior of the two progenies tested, while the latter was very evident when comparing the upper and lower halves of ears. For some unknown physiological reason, the elimination is generally stronger in the upper than in the lower half of the ear. 4) The female elimination of the sp gene may be caused theoretically, by either of two processes: a simple lethal effect in the female gametophyte or a competition between megaspores. The former would lead not only to the abortion of the individual megaspores, but of the whole uniovulate ovary. In the case of the latter, the abortive megaspore carrying the gene sp will be substituted in each ovule by one of the Sp megaspores and no abortion of ovaries may be observed. My observations are completely in favor of the second explication: a) The ears were as a whole very well filled except for a few incomplete ears which always appear in artificial pollinations. b) Row arrangement was always very regular. c) The number of kernels on ears with elimination is not smaller than in normal ears, but is incidentally higher : with elimnation, in back-crosses 354 kernels and in selfed ears 390 kernels, without elimination 310 kernels per ear. d) There is no correlation between the intensity of elimination and the number of grains in individual ears; the coefficient; of linear correlation, equal to 0,24, is small and insignificant. e) Our results are in complete disagreement whit those reported by SINGLETON and MANGELSDORF (1940). Since these authors present only pooled date, a complete and detailed analysis which may explain the cause of these divergences is impossible.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Lutosa brasiliensis, an Orthopteran Tettigonioidean belonging to the family Stenopelmatidae is referred to in this paper The spermatogonia are provided with 15 chromosomes, that is, 7 pairs of autosomes and a single sex chromosome. One pair of autosomes is much larger than the rest, two pairs are of median sized elements, and four pairs are of small ones. The daughter sex chromosomes show at anaphase great difficulty in reaching the poles, being left for a long while in the region of the equator where they are seen stretched one after the other on the same line or lying side by side in different positions. When the spermatogonium divides each daughter cell gets passively its sex chromosome. Though slowly, the sex chromosome finishes by beins enclosed in the nucleus. Its behavior may be attributed to a very weak kinetic activity of the centromere. In view of se pronouced an inertness of the sex chromosomes, two things may be expected : primary spermatocyte nuclei with two sex chromosomes, and primary spermatocytes with the sex chromosome lying outside the nucleus. Both situations have been discovered. The latter, together with the delay of the spermatogonial sex chromosome in reaching the poles suggested to the anther the mechanism which might have given origin to the cases in which the sex chromosome normally does not enter the nucleus to rejoin the autosomes, remaning outside in its own nucleus. It may well be supposed that accidents like that found in the present individual have turned to be a normal event in the course of the evolution of some species. Trie primary spermatocytes are provided with chromatoid bodies which remain visible all over the whole history of the cells and pass to one of the resulting secondary spermatocytes, the larger of them being found later in the area occupied by the tails of the spermatozoa. No relation of these bodies to nucleoli con?d be established. Pachytene and diplotene nuclei are normal Metaphase nuclei show 7 autosomal tetrads, one of which being much larger than the rest. At this stage the chromosomes have a pronounced tendency to form clumps. Even when they are separated from each other they generally appear competed by chromosomal substance. The sex chromosome Hes always in one of the poles, being enclosed in the nucleus formed there. The stickness of the chromosomes can also be noted at anaphase. Telophase chromosomes distend them- selves for giving origin to secondary spermatocyte nuclei in a state comparable to a beginning prophase. As the secondary spermatocytes approach metaphase the autosomes appear entirely divided except at the kinetochore where the chromatids remain united. In the division of the secondary spermatocytes nothing else merits special reference.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Magdeburg, Univ., Med. Fak., Diss., 2012

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper devotes to evaluation of performance bottlenecks and algorithm deficiencies in the area of contemporary reliable multicast networking. Hereby, the impact of packet delay jitter on the end-to-end performance of multicast IP data transport is investigated. A series of tests with two most significant open-source implementations of reliable multicast is performed and analyzed. These are: UDP-based File Transfer Protocol (UFTP) and NACK-oriented Reliable multicast (NORM). Tests were targeted to simulate scenario of content distribution in WAN – sized Content Delivery Networks (CDN). Then, results were grouped and averaged, by round trip time and packet losses. This enabled us to see jitter influence independently on round trip time(RTT) and packet loss rates. Revealed jitter influence for different network conditions. Confirmed, that appearance of even small jitter causes significant data rate reduction.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A key to species groups of the genus Belostoma Latreille, 1807, using new taxonomic characters are presented as well as the revision of the four species included in the denticolle group: B. denticolle Montandon, 1903, and three new species: B. orbiculatum from eastern Argentina and southern Brazil, B. retusum from eastern Argentina and B. amazonum from northern Brazil which are described and illustrated.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

v.34:no.35(1955)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

v.20:no.21(1936)