1,721,089 research outputs found
Acid phosphatase locus 1 (ACP1): Possible relationship of allelic variation to body size and human population adaptation to thermal stress - A theoretical perspective
No full textThe acid phosphatase locus 1 (ACP1) codes for a low molecular weight phosphotyrosine protein phosphatase that has the important action of dephosphorylating tyrosine phosphorylated proteins and peptides and a second important role in modulating flavin cofactor levels and the activity of flavo-enzymes. These functions significantly influence cell division, differentiation, and growth. Two alleles (ACP1*A and ACP1*B) reach polymorphic frequencies at the ACP1 locus in all human populations, while the ACP1*C and ACP1*R alleles reach polymorphic frequencies in restricted geographical regions. The worldwide distribution of these alleles, and data from several clinical studies, strongly suggest that the ACP1 locus functions to modulate growth and that selection at this locus is a component of the selective processes influencing body mass and human population adaptation to thermal stress. The ACP1*A allele reaches highest frequencies at extreme latitudes and appears to be associated with maximizing body mass and adaptation to cold stress, whereas the ACP1*B allele reaches highest frequencies in tropical and subtropical environments and appears to be associated with minimizing body mass and adaptation to heat stress. The high frequency of the ACP1*C allele at northern latitudes, where ACP1*A allele frequencies are elevated, may be a mechanism for limiting fetal and maternal complications associated with fetal macrosomia and adult obesity in populations where protein and calorie intake are relatively hig
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
Further Observations on Associations Between the ADA Gene and Past Malaria Morbidity in Sardinia.
No full textObjectives: Adenosine Deaminase (ADA) contributes to the regulation of adenosine concentration and in turn to T cell activation. Genetic variability of ADA activity may have, therefore, an important role in resistance to malaria.
Indeed, previous studies in Sardinia have shown a lower frequency of ADA1*2 allele (associated with low ADA activity)
in areas, where malaria was heavily endemic compared to areas where malaria was not endemic. We have now studied
the ADA2 locus, another polymorphic site with two alleles ADA2 *1 and ADA2 *2 within the ADA gene.
Methods: In the area of Oristano (where malaria was endemic in the past) 51 consecutive newborns and in the area
of Nuoro (where malaria was not as endemic) 48 consecutive newborns were examined.
ADA1 and ADA2 genotypes were determined by DNA analysis.
Results: The low frequency of the ADA1*2 allele in the area where malaria was endemic is confirmed. The frequency
of the ADA2*2 allele is higher in Oristano than in Nuoro resulting in a higher frequency of the ADA1*1/ADA2*2 haplotype
in Oristano as compared to Nuoro. This suggests a selective advantage of this haplotype in a malarial
environment.
Conclusions: The ADA gene shows other polymorphic sites further studies on their role in human adaptation to
malaria could be rewarding
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A study of acid phosphatase locus 1 in women with high fat content and normal body mass index
Full text linkDe Lorenzo and coworkers have recently described a class of women with normal body mass index (BMI) and high fat content (normal weight obese syndrome [NWO]). This observation prompted us to study the possible role of acid phosphatase locus 1 (ACP(1)) in the differentiation of this special class of obese subjects. Acid phosphatase locus 1 is a polymorphic gene associated with severe obesity and with total cholesterol and triglycerides levels. The enzyme is composed by 2 isoforms--F and S--that have different biochemical properties and probably different functions. The sample study was composed of 130 white women from the population of Rome. Total fat mass and percentage of fat mass were measured by dual-energy x-ray absorptiometry. Thirty-six women had a BMI less than 25 and percentage of fat mass greater than 30 (high fat, normal BMI [HFHB]), and 94 women showed a BMI greater than 25 and a percentage of fat mass greater than 30 (high fat, high BMI [HFHB]). In the whole sample, the proportion of low-activity ACP(1) genotypes (*A/*A and *B/*A) was higher than in controls. However, whereas HFNB showed a very high frequency of ACP(1) *A/*A genotype, high-fat, high-BMI women showed an increase of *B/*A genotype. These 2 genotypes differ in the concentration of F isoform and the F/S ratio, which are lower in ACP(1)*A/*A genotype than in ACP(1)*B/*A genotype. The genetic differentiation of the class of women with normal BMI and high fat content from the class showing a concordant level of the 2 parameters supports the hypothesis that HFNB class represents a special cluster of obese subjects not revealed by BMI evaluation. Because ACP(1) is present in adipocytes, the present observation suggests that F isoform may have a specific role in the regulation of quantity of adipose tissue
Coronary Artery Disease: Evidence of Interaction between PTPN22 and p53 Genetic Polymorphisms
No full textObjectives: We recently reported an association between the PTPN22 genetic polymorphism and coronary artery disease (CAD) in nondiabetic subjects. Since recent studies suggest that p53 may be involved in coronary atherosclerosis, we have investigated a possible interaction between PTPN22 and p53 codon 72 genetic polymorphisms regarding their effects on susceptibility to CAD in nondiabetic subjects. Methods: The genotypes of p53 codon 72 and PTPN22 were determined by DNA analysis in 128 nondiabetic subjects with CAD, 122 healthy blood donors and 117 nondiabetic subjects with cardiovascular diseases without CAD. Results: In subjects with the *Arg/*Arg genotype of p53 codon 72, no association was observed between CAD and PTPN22. However, this association was very strong in subjects carrying the *Pro allele of p53 codon 72. Subjects carrying both the *T allele of PTPN22 and the *Pro allele of p53 were overrepresented in CAD nondiabetic cases relative to the other two groups (p = 0.001). Conclusions: Since both p53 and PTPN22 are involved in autoimmune inflammation, an interaction between the two systems appears biologically plausible. In the analysis of multifactorial disorders, the simultaneous analysis of multiple genes functionally related to diseases will provide a more productive approach than studies of single genetic factors performed from a Mendelian perspective
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