930 resultados para PARTNER CHROMOSOMES


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Inorganic Chemistry 50(21):10600-7

Relevância:

10.00% 10.00%

Publicador:

Resumo:

J Biol Inorg Chem (2011) 16:1241–1254 DOI 10.1007/s00775-011-0812-9

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Males from bilateral crosses between Triatoma sórdida and Triatoma pseudomaculata were unable to give offspring, as shown by subsequent backcrosses (BC) between hybrid males and parental females. This kind of sterility indueed through interspecific hybridization seems to be due to lack of sperm migration from the bursa copulatrix to the spermateca, thus suggesting primarily failure on the part of hybrid males to produce and/or to incorporate male accessory secretions into the spermatophore bulb. Addicional proof that sterility induced in hybrid males is at the sperm level has been afforded by the spermatogenesis herein studied. The anomalous processes like; 1) prophases of spermatogonia with the chromosomes scattered in the cytoplasm, 2) first metaphases with unpaired tetrades, 3) spermatids differing in size and 4) spermatozoa of abnormal shape and generdlly of giant size, can be taken as an indicator of the degree of departure from the normal course of spermatogenesis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background. HIV infected women have higher rates of infertility. Objective. The purpose of this literature review is to evaluate the effectiveness of fresh IVF/ICSI cycles in HIV infected women. Materials and Methods. A search of the PubMed database was performed to identify studies assessing fresh nondonor oocyte IVF/ICSI cycle outcomes of serodiscordant couples with an HIV infected female partner. Results and Discussion. Ten studies met the inclusion criteria. Whenever a comparison with a control group was available, with the exception of one case, ovarian stimulation cancelation rate was higher and pregnancy rate (PR) was lower in HIV infected women. However, statistically significant differences in both rates were only seen in one and two studies, respectively. A number of noncontrolled sources of bias for IVF outcome were identified. This fact, added to the small size of samples studied and heterogeneity in study design and methodology, still hampers the performance of a meta-analysis on the issue. Conclusion. Prospective matched case-control studies are necessary for the understanding of the specific effects of HIV infection on ovarian response and ART outcome.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Combined pituitary hormone deficiency (CPHD) has an incidence of approximately 1 in 8000 births. Although the proportion of familial CPHD cases is unknown, about 10% have an affected first degree relative. We have recently reported three mutations in the PROP1 gene that cause CPHD in human subjects. We report here the frequency of one of these mutations, a 301-302delAG deletion in exon 2 of PROP1, in 10 independently ascertained CPHD kindreds and 21 sporadic cases of CPHD from 8 different countries. Our results show that 55% (11 of 20) of PROP1 alleles have the 301-302delAG deletion in familial CPHD cases. Interestingly, although only 12% (5 of 42) of the PROP1 alleles of our 21 sporadic cases were 301-302delAG, the frequency of this allele (in 20 of 21 of the sporadic subjects given TRH stimulation tests) was 50% (3 of 6) and 0% (0 of 34) in the CPHD cases with pituitary and hypothalamic defects, respectively. Using whole genome radiation hybrid analysis, we localized the PROP1 gene to the distal end of chromosome 5q and identified a tightly linked polymorphic marker, D5S408, which can be used in segregation studies. Analysis of this marker in affected subjects with the 301-302delAG deletion suggests that rather than being inherited from a common founder, the 301-302delAG may be a recurring mutation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dissertação para a obtenção do grau de doutor em Biologia pelo Instituto de Tecnologia Química e Biológica. Universidade Nova de Lisboa

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dissertation presented to obtain the Ph.D degree in Biology, Cell Biology

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dissertation presented to obtain the Ph.D degree in Molecular Biology

Relevância:

10.00% 10.00%

Publicador:

Resumo:

RESUMO: A surdez súbita (SS) caracteriza-se por uma perda abrupta de audição, mais frequentemente unilateral e associada a sensação de preenchimento aural, acufenos e vertigem. Afecta 5-20/100.000pessoas/ano (sobretudo adultos em fase activa na década de 40), com grande impacto na qualidade de vida. Possíveis causas incluem doenças infecciosas, circulatórias, traumáticas, imunológicas, neoplásicas, neurológicas, tóxicas e cocleares. No entanto, a causa da SS permanece desconhecida na maioria dos casos (80%), o que origina tratamentos controversos e frequentemente ineficientes. Os tratamentos disponíveis variam desde corticosteróides a antivirais, vasodilatadores, anti-agregantes, anticoagulantes, vitaminas e oxigénio hiperbárico (OHB). Atendendo a falta de informação relativa à etiologia e fisiopatologia da SS, pretendemos avaliar a evolução clínica dos doentes com SS tratados com OHB no Centro de Medicina Subaquática e Hiperbárica (CMSH) de Lisboa entre 2000 e 2005, durante um período mínimo de 5 anos, na tentativa de identificar eventuais factores de risco ou noxas clínicas com a SS. O estudo retrospectivo proposto baseia-se na revisão de processos clínicos do CMSH e na aplicação telefónica de questionários médicos de “follow-up” confidenciais – tanto a doentes (grupo de estudo), como aos respectivos esposos/companheiros/membros próximos da família (grupo de controlo) –, com particular ênfase nos antecedentes médicos e história clínica actual. Um estudo preliminar de 20 pessoas (10 doentes e 10 controlos) foi efectuado para antecipar dificuldades e estimar as necessidades logísticas. As dificuldades identificadas foram: 1) selecção dos doentes com números de telefone válidos e processos clínicos completos (com audiograma inicial e final); 2) contacto telefónico com os participantes de ambos os grupos (de estudo e controlo); 3) recursos humanos requeridos. Dado que a SS não é uma doença em si, mas um sintoma de uma doença subjacente, acreditamos que este estudo epidemiológico seja importante e útil, capaz de gerar novas luzes sobre a fisiopatologia e mecanismos desta entidade clínica.-------------ABSTRACT:Sudden sensorineural hearing loss (SSHL) is characterized by abrupt, mostly unilateral loss of hearing, frequently associated to aural fullness, tinnitus and vertigo. It affects 5-20/100.000 people/year (particularly working adults in the 40ths), with huge impact on quality of life. Possible causes include infectious, circulatory, traumatic, immunologic, metabolic, neoplastic, neurologic, toxic and unidentified cochlear diseases. Nevertheless, SSHL’s etiology remains unknown in most cases (80%), giving rise to controversial (and frequently ineffective) treatments. Available therapies range from corticosteroids to antivirals, vasodilators, antiaggregants, anticoagulants, vitamins and hyperbaric oxygen (HBO). Given the lack of data concerning SSHL’s etiology and physiopathology, we intend to evaluate clinical evolution of such patients treated with HBO in the Underwater and Hyperbaric Medical Center (UHMC) at Lisbon from 2000 to 2005 during a minimum period of 5 years, in an attempt to identify eventual risk factors or clinical associations to SSHL. The intended retrospective study is based on the review of patients’ medical charts from UHMC and confidential follow-up questionnaires applied telephonically both to patients (study group) and patients’ spouse/partner/close family member (control group), focusing past and present medical history. A preliminary study of 20 subjects (10 of each group) was performed to anticipate difficulties and to estimate the required logistics. The identified difficulties were: 1) selection of subjects with valid phone numbers and complete medical charts (with initial and final audiograms); 2) telephonic contact with subjects from the study and control group; 3) human logistics required. As it is believed that SSHL is not a disease by itself but rather a symptom of an underlying disease, we believe that this epidemiologic study is important and will hopefully generate sound scientific knowledge concerning physiopathology and mechanism of disease of SSHL.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We use an adverse selection model to study the dynamics of firms' reputations when firms implement joint projects. We show that in contrast with projects implemented by a single firm, in the case of joint projects a firm's reputation does not necessarily increase following a success and does not necessarily decrease following a failure. We also study how reputation considerations affect firms ' decisions to participate in joint projects. We show that a high quality partner may not be preferable to a low quality partner, and that a high reputation partner is not necessarily preferable to a low reputation partner.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Abstract: Selection among broilers for performance traits is resulting in locomotion problems and bone disorders, once skeletal structure is not strong enough to support body weight in broilers with high growth rates. In this study, genetic parameters were estimated for body weight at 42 days of age (BW42), and tibia traits (length, width, and weight) in a population of broiler chickens. Quantitative trait loci (QTL) were identified for tibia traits to expand our knowledge of the genetic architecture of the broiler population. Genetic correlations ranged from 0.56 +/- 0.18 (between tibia length and BW42) to 0.89 +/- 0.06 (between tibia width and weight), suggesting that these traits are either controlled by pleiotropic genes or by genes that are in linkage disequilibrium. For QTL mapping, the genome was scanned with 127 microsatellites, representing a coverage of 2630 cM. Eight QTL were mapped on Gallus gallus chromosomes (GGA): GGA1, GGA4, GGA6, GGA13, and GGA24. The QTL regions for tibia length and weight were mapped on GGA1, between LEI0079 and MCW145 markers. The gene DACH1 is located in this region; this gene acts to form the apical ectodermal ridge, responsible for limb development. Body weight at 42 days of age was included in the model as a covariate for selection effect of bone traits. Two QTL were found for tibia weight on GGA2 and GGA4, and one for tibia width on GGA3. Information originating from these QTL will assist in the search for candidate genes for these bone traits in future studies.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cell division is a highly dynamic process where sister chromatids remain associated with each other from the moment of DNA replication until the later stages of mitosis, giving rise to two daughter cells with equal genomes. The “molecular glue” that links sister DNA molecules is called cohesin, a tripartite ring-like protein complex composed of two Structural Maintenance of Chromosome proteins (Smc1 and Smc3) bridged by a kleisin subunit Rad21/Scc1, that together prevent precocious sister chromatid separation. Accumulating evidence has suggested that cohesion decay may be the cause of segregation errors that underlie certain human pathologies. However it remains to be determined how much cohesin loss abolishes functional sister chromatid cohesion. To answer these questions, we have developed different experimental conditions aiming to titrate the levels of cohesin on mitotic chromosomes in a precise manner. Using these tools, we will determine the minimal amount of cohesin needed to confer functional cohesion. The approaches described here take advantage of a system in Drosophila melanogaster where the Tobacco Etch Virus (TEV) protease can cleave the Rad21 subunit of cohesin leading to precocious sister chromatid separation. Firstly, we tried to express different levels of TEV protease to obtain partial loss of cohesion. However, this approach has failed to produce systematic different levels of sister chromatid separation. Most of the work was therefore focused on a second strategy, for which we established strains with different levels of cohesin sensitive/cohesin resistant to TEV protease. Strains containing different amounts of functional cohesin (TEV resistant) were tested by in vitro cleavage and by in vivo injections in embryos for their ability to promote sister chromatid cohesion. Our results reveal that removal of half of the cohesin complexes does not impair chromosome segregation, implying that chromosome cohesion is less sensitive to cohesin amounts than previously anticipated.