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Biomedical subjects

A Piazza

Publications and source records attributed to A Piazza.

At least 55 records · Page 3Linked to original sources
PubMed1996

Genetic analysis of Sardinia: I. data on 12 polymorphisms in 21 linguistic domains.

(1) The microgeographic structure of Sardinia, well documented from a historical and linguistic point of view, further supported by archaeological evidence, can also be dissected at the genetic level: gene frequencies show heterogeneities which are statistically significant. (2) Dendrogram analyses performed with different methods lead to the same result: even if gene frequencies cluster linguistically defined geographic domains in agreement with historical and archaeological evidence, no phylogenetic tree can be inferred, very likely because the assumptions which allow a phylogenetic tree to be a valid model of evolution (mainly constant evolutionary rates and independence between branches) do not apply to the genetic history of Sardinia. (3) Evidence of a qualitative association between distribution of genes and distribution of languages or dialects seems to emerge also at the microgeographic level of our analysis. More linguistic and genetic data are planned to be considered.

Female↗
PubMed1995

Genetics and the origin of European languages.

A new set of European genetic data has been analyzed to dissect independent patterns of geographic variation. The most important cause of European genetic variation has been confirmed to correspond to the migration of Neolithic farmers from the area of origin of agriculture in the Middle East. The next most important component of genetic variation is apparently associated with a north-south gradient possibly due to adaptation to cold climates but also to the differentiation of the Uralic and the Indo-European language-speaking people; however, the relevant correlations are not significantly different from zero after elimination of the spatial autocorrelation. The third component is highly correlated with the infiltration of the Yamna ("Kurgan") people, nomadic pastoralists who domesticated the horse and who have been claimed to have spread Indo-European languages to Europe; this association, which is statistically significant even when taking spatial autocorrelations into account, does not completely exclude the hypothesis of Indo-European as the language of Neolithic farmers. It is possible that both expansions were responsible for the spread of different subfamilies of Indo-European languages, but our genetic data cannot resolve their relative importance.

Alleles↗
PubMed1995

Effect of aging on left ventricular filling in untreated hypertensive patients.

The aim of this study was to evaluate the influence of age and other clinical and echocardiographic parameters on left ventricular filling in a group of 174 untreated patients with mild to moderate hypertension (aged 20-82 years; mean 51.2 years) and in 189 age-matched normotensive subjects. All subjects underwent an echocardiographic study with pulsed Doppler evaluation of left ventricular filling. Left ventricular dimensions and indexes of systolic function were similar and within normal limits in both groups. Left ventricular filling was altered in hypertensive subjects < 65 years with a decrease of peak early velocity (peak E), an increase of peak atrial velocity (peak A) and a reduced E/A ratio. However in subjects > or = 65 years, we did not observe any differences in transmitral flow velocity pattern between hypertensive and normotensive subjects. The stepwise regression analysis showed that age alone explains up to 8% of peak E variance, 14% of peak A and 26% of E/A ratio in hypertensives, while in normotensives it explains up to 18% of peak E variance, 50% of peak A and 61% of E/A ratio. The other variables entered into the regression slightly improved the predictive power. In conclusion, age is the major independent factor affecting left ventricular filling in both groups, even if its predictive power was smaller in the hypertensive group. The similarity of diastolic filling pattern in elderly hypertensive and normotensive subjects suggests that the 'aging factor' plays an important role in influencing left ventricular filling pattern so as to mask the effect of hypertension in the elderly patients.

Adult↗
PubMed1995

Analysis of HLA-A, C, B, DR and DQ loci in an Italian sample of possible Celtic origin.

Trino Vercellese, a village of Piedmont (Italy), was selected with the aim at reconstructing the genetic history of a putative Celtic sample known to be settled in Italy with the name of Rigomagus since pre-roman times. The HLA-A, Cw, B, DR and DQ antigens of 101 unrelated individuals have been typed. The antigens characterizing this sample for their higher frequency are shown to be A3, A11, A32, B35, B39, Bw52, Cw4, DRw11, DRw13, DQw7. Gene frequencies are estimated by maximum likelihood and Hardy-Weinberg equilibrium was tested with no deviant genetic locus. Two-locus haplotype frequencies were also estimated and those with significant associations tabulated. "Extended" haplotypes were reconstructed: the three most frequent haplotypes (covering a total frequency of 11.5%) share the same Cw, B, DR and DQ alleles. Comparisons with other Italian and European samples are indicated to challenge archeological evidence of a pre-roman genetic stratification of the people living in our old Rigomagus.

Alleles↗
PubMed1994

RFLP analysis on a sample from northern Italy.

We analysed a sample of 55 unrelated individuals from Trino Vercellese, a village in northern Italy. It represents the only European sample which is unmixed in a comparative study of eight populations from four continents [Bowcock et al 1991a; Lin et al 1994]. RFLP analysis was performed on 32 DNA markers, for a total of 37 independent alleles. Genetic variability between populations was measured by the FST statistics (average FST is 0.138). Average heterozygosity was calculated for each marker and for each population. Genetic distances were evaluated between pairs of populations. Phylogenetic trees were reconstructed and principal component analysis performed.

Alleles↗
PubMed1994

[Retroperitoneal ganglioneuroma. A case report and review of the literature].

Ganglioneuromas are typically of slow growth and benign evolution and may remain clinically silent for a considerable time if favourably situated. Many large examples are discovered incidentally on X-ray examination, routine abdominal palpation or at necropsy. Ganglioneuromas are often encountered in childhood and are found more frequently in the posterior mediastinum than in any other single situation; other sites are the lumbar and pelvic retroperitoneal tissues, the gastrointestinal tract and the mesentery. Diffuse alimentary tract ganglioneuromatosis has been described as port of the multiple endocrine neoplasia syndrome (MEN) type II-B. Sometimes ganglioneuromas are found in the von Recklinghausen Syndrome. The authors report in this paper a rare case of a retropancreatic ganglioneuromas.

Female↗
PubMed1993

Demic expansions and human evolution.

Geographic expansions are caused by successful innovations, biological or cultural, that favor local growth and movement. They have had a powerful effect in determining the present patterns of human genetic geography. Modern human populations expanded rapidly across the Earth in the last 100,000 years. At the end of the Paleolithic (10,000 years ago) only a few islands and other areas were unoccupied. The number of inhabitants was then about one thousand times smaller than it is now. Population densities were low throughout the Paleolithic, and random genetic drift was therefore especially effective. Major genetic differences between living human groups must have evolved at that time. Population growths that began afterward, especially with the spread of agriculture, progressively reduced the drift in population and the resulting genetic differentiation. Genetic traces of the expansions that these growths determined are still recognizable.

Animals↗
PubMed1993

Human genomic diversity in Europe: a summary of recent research and prospects for the future.

Gene frequencies in Europe are intermediate with respect to those of other continents. A phylogenetic tree reconstructed from 95 gene frequencies tested on 26 European samples shows some deviant populations (Lapps, Sardinians, Greeks, Yugoslavs, Basques, Icelanders and Finns) and other weakly structured populations. This behavior may have a simple interpretation: Europeans have not evolved according to a tree of descent probably because of the major role played by migrations in prehistorical and historical times. The leading component of the European genetic landscape is a gradient that originates in the Middle East and is directed to the northwest. According to the hypothesis by Ammerman and Cavalli-Sforza this gradient was generated by a migration of Neolithic farmers from Anatolia followed by continuous, partial admixture of the expanding farmers with local hunter-gatherers. Other leading components of the gene frequencies in Europe show correlations with possible movements of Uralic-speaking people and pastoral nomads from a region north of the Caucasus and Black Sea, which according to Gimbutas is the area of origin of Indo-European speakers. This analysis is based on classical pre-DNA genetic markers. The prospect of future research using DNA polymorphisms is discussed in the context of the Human Genome Project.

Africa↗
PubMed1992

Multivariate analysis of the variables affecting left ventricular filling in normal subjects.

Pulsed Doppler measurements of left ventricular filling (LVF), two-dimensional and M-mode echocardiograms were performed in 189 healthy subjects, in order to evaluate factors influencing LVF Doppler indexes in normal subjects. LVF Doppler indexes (peak E, peak A, peak E/peak A, deceleration rate of peak E (ED) were related by univariate and multivariate analyses with the following parameters: age, sex, heart rate, systolic and diastolic blood pressure, aortic root and left atrial dimensions, left ventricular mass index, left ventricular shortening fraction. The stepwise analysis showed that age by itself explained up to 18% of peak E variance, 50% of peak A variance, 61% of peak E/peak A variance and 25% of ED variance. The other variables entered into the regression, slightly improved the predictive power (less than 10%). In conclusion, age is the major independent factor affecting LVF in normal subjects, although other variables show significant correlation also after age adjustment.

Age Factors↗