1,720,989 research outputs found
Human placental 17 beta-estradiol dehydrogenase: enzymatic activity in the last weeks of pregnancy and electrophoretic data.
No full textKinetic properties of the common electrophoretic variants of human S-adenosylhomocysteine hydrolase (AHCY): The effect of four nucleoside analogue inhibitors
No full textRed blood cell S-adenosylhomocysteine hydrolase (AHCY) from individuals of 1, 2-1 and 3-1 phenotypes was partially purified and K(m) and V(max) determined in the absence and in the presence of the following inhibitors: 3-deaza-adenosine (DZA), 3-deaza-aristeromycin (DZAry), 2-chloro adenosine (2-Cl-ado) and purine riboside (or nebularine). The three phenotypes 1, 2-1, 3-1 showed similar K(m) (32.58, 39.22 and 34.84μM respectively), but the ratio K(m)/V(max) was statistically different. DZA and DZAry appeared to be strong competitive inhibitors. The AHCY 1 phenotype was more resistant to their action, while the 3-1 variant was more sensitive. 2-Cl-ado and purine riboside were weaker inhibitors; the type of inhibition varied among the three phenotypes, but, again, the AHCY 1 phenotype was less sensitive than the other two
How contemporary human reproductive behaviours influence the role of fertility-related genes: the example of the P53 gene.
No full textRecently numerous polymorphic fertility genes have been associated with reproductive system diseases causing infertility/subfertility. nvestigations carried out in populations at natural fertility suggest that some fertility genes have acquired clinical relevance only in the last decades due to the interaction with contemporary reproductive behaviours (birth control, delayed childbearing, and spacing birth order among others). In recent years, a new physiological role in human fertility regulation has emerged for the tumor suppressor p53 gene (P53), and the P53 Arg72Pro polymorphism has been associated with recurrent implantation failure in humans. In order to detect a possible interaction between fertility gene P53 and reproductive patterns, in present investigation we examined the impact of Arg72Pro polymorphism on fertility in two samples of Italian women collected from populations with different (premodern and modern) reproductive behaviours, not selected for impaired fertility. Among the women at near-natural fertility(n=98), the P53 genotypes were not associated with different reproductive efficiency, whereas among those with modern reproductive behaviours (n=68), the P53 genotypes were associated with different mean numbers of children (Pro/Pro <Pro/Arg <Arg/Arg, =0.056) and a significant negative relationship between the number of children and P53 Pro allele frequencies (p=0.028) was observed. These results are consistent with those of clinical studies reporting an association between the P53 Pro allele and recurrent implantation failure. These findings seem to support the hypothesis that some common variants of fertility genes may have become “detrimental” following exposure to modern reproductive patterns and might t therefore be associated with reduced reproductive success
C3 polymorphism and the antibody titres in pregnancy: use of a non-barbital buffer for C3 typing.
No full textThe C3 phenotypes were examined in 391 pregnant women classified according to the level of 'immune', 'natural' and 'irregular' antibody titres. No significant association between the C3 types and antibody levels was found. The sera were also typed for C3 with a non-barbital buffer
Human placental alkaline phosphatase: Analysis of genetically determined rare variants
No full textIn a survey on 2405 placentae of different ethnic origin evidence for at least 11 different mutated alleles at Pl locus was obtained by identifying 60 rate variants of human placental alkaline phosphatase
Association of CYP19 and ESR1 Pleiotropic Genes With Human Longevity
No full textAromatase (CYP19) and estrogen receptor-alpha (ESR1) are involved in the metabolism of estrogens, which have a relevant role in female and male aging. Moreover, due to their influence on fertility, both genes may be part of the longevity-fertility trade-off mechanism. This investigation examines the association of ESR1 (PvuII and XbaI) and CYP19 (rs4646) polymorphisms with longevity. A sample of 258 individuals (mean age = 83.1 +/- 5.7 years) was recruited in 2000. Based on mortality data collected in 2009, the sample was divided into two groups of participants surviving more than 90 years or not. The analysis showed that ESR1 PP (odds ratio = 2.2) and CYP19 genotypes carrying the T allele (odds ratio = 1.9) were significantly associated with longevity (survival to age more than 90 years). As the ESR1 PP genotypes were found associated with reduced fertility in the same sample, we may infer that ESR1 genotypes could exert an antagonistic pleiotropic effect on longevity and fertility
Association of ACE I/D polymorphism and recurrent miscarriages in an Italian population with a pre-modern reproductive pattern
No full textAngiotensin I-converting enzyme (ACE), in addition to its role in the renin angiotensin system, has a physiological function in the fibrinolysis pathway, the accurate control of which is critical for the normal development of pregnancy. Recently, the ACE I/D polymorphism was found to be associated with recurrent spontaneous miscarriages (RM). The present study analysed the relationship between ACE I/D polymorphism and the number of spontaneous miscarriages, the number of pregnancies and the number of children in a sample of 88 Italian women born before 1930, with a pre-modern reproductive behaviour. The ACE DD genotype was more prevalent among women with RM (p = 0.02). However, the women carrying the DD genotype not only had the highest number of miscarriages (p = 0.03), but also the highest number of pregnancies with an eventual complete fertility (children no = 4.4), similar to that of women carrying the other ACE genotypes. In contrast, published data on contemporary women with RM seem to indicate that the DD genotype could now be associated with a reduced reproductive success compared to the other ACE genotypes. It is suggested that this phenomenon may be the effect of the interaction between ACE genotypes and contemporary reproductive behaviours (delay in childbearing, below-replacement fertility)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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