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Biomedical subjects

A Piazza

Publications and source records attributed to A Piazza.

At least 91 records · Page 5Linked to original sources
PubMed1989

[Effects of digitalis on the left ventricular filling phase in the normal and ischemic heart. Angiographic study in man].

The effects of digitalis on the left ventricular diastolic phase are very scant. In order to gain a better insight into this problem, we measured the hemodynamic effects of an intravenous injection of K-strophantidin (0.005 mg/kg in a bolus given within 5-10 min) during the diastolic phase in 9 normal male subjects and in 9 male patients with coronary artery disease (CAD), maintaining a normal overall ejection fraction despite of the presence of some hypokinetic segments. Administration of K-strophantidin decreased significantly in normal controls the left ventricular volumes at 1/3, 1/2, 2/3 of the diastolic phase, whereas it did not produce significant change in CAD patients. Digitalis decreased the first and increased the second filling peak of the volumetric variable dV/dt in the normal controls, but not in the CAD patients. In the latter group the 2 peaks before digitalis administration were similar. The effects of digitalis on the dV/dt measured during the second filling peak were significantly different in the 2 groups. The increments of pressure in middle and end diastole in CAD patients were significantly greater than those observed in normal controls. Results of the present study suggest that digitalis has a negative influence on the left ventricular filling phase both in normal and CAD subjects. In fact digitalis modifies in normals the pattern of the left ventricular filling phase whereas it induces an untoward increase in the middle and end diastolic pressure in CAD patients.

Adult↗
PubMed1988

Trypsin digestion of junctional sarcoplasmic reticulum vesicles.

A putative constituent of the junctional processes, connecting the terminal cisternae of sarcoplasmic reticulum and the transverse tubules of skeletal muscle fibers, is a greater than or equal to 350,000-dalton (Da) protein that displays ryanodine binding and Ca2+ channel properties. Ryanodine modulation of Ca2+ fluxes suggests that the ryanodine receptor and calcium channel are integral parts of one functional unit corresponding to the greater than or equal to 350,000-Da protein [Inui, M., Saito, E., & Fleischer, S. (1987) J. Biol. Chem. 262, 1740-1747; Campbell, K. P., Knudson, C. M., Imagawa, T., Leung, A. L., Sutko, J. L., Kahl, S. D., Raab, C. R., & Madson, L. (1987) J. Biol. Chem. 262, 6460-6463]. We subjected vesicular fragments of junctional-cisternal membrane to stepwise trypsin digestion. The greater than or equal to 350,000-Da protein is selectively cleaved in the early stage of digestion, with consequent disappearance of the corresponding band in electrophoretic gels. The Ca2+-ATPase is cleaved at a later stage, while calsequestrin is not digested under the same experimental conditions. While the Ca2+-ATPase yields two complementary fragments that are relatively resistant to further digestion, the greater than or equal to 350,000-Da protein yields fragments that are rapidly broken down to small peptides. Under conditions producing extensive digestion of the greater than or equal to 350,000-Da protein, the junctional processes are still visualized by electron microscopy, with no discernible alterations of their ultrastructure. The functional properties of the Ca2+ release channel are also maintained following trypsin digestion, including blockage by Mg2+ and ruthenium red and activation by Ca2+ and nucleotides.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Reconstruction of human evolution: bringing together genetic, archaeological, and linguistic data.

The genetic information for this work came from a very large collection of gene frequencies for "classical" (non-DNA) polymorphisms of the world aborigines. The data were grouped in 42 populations studied for 120 alleles. The reconstruction of human evolutionary history thus generated was checked with statistical techniques such as "boot-strapping". It changes some earlier conclusions and is in agreement with more recent ones, including published and unpublished DNA-marker results. The first split in the phylogenetic tree separates Africans from non-Africans, and the second separates two major clusters, one corresponding to Caucasoids, East Asians, Arctic populations, and American natives, and the other to Southeast Asians (mainland and insular), Pacific islanders, and New Guineans and Australians. Average genetic distances between the most important clusters are proportional to archaeological separation times. Linguistic families correspond to groups of populations with very few, easily understood overlaps, and their origin can be given a time frame. Linguistic superfamilies show remarkable correspondence with the two major clusters, indicating considerable parallelism between genetic and linguistic evolution. The latest step in language development may have been an important factor determining the rapid expansion that followed the appearance of modern humans and the demise of Neanderthals.

Archaeology↗
PubMed1988

A genetic history of Italy.

Statistical techniques for displaying the geographical distribution of many genes in few synthetic images have been used to represent the various patterns of gene frequencies in Europe and in the world (Menozzi et al. 1978; Piazza et al. 1981 a). It has also been shown that such synthetic displays are particularly useful in detecting clines of genetic differentiation associated with movements of populations like those accompanying the Neolithic expansion of farmers from the Near East or, in more recent times, the putative diffusion of Indo-European-speaking populations (Ammerman & Cavalli-Sforza, 1984; Gimbutas, 1973). In this paper we use the same combination of statistical and graphical techniques to study the genetic structure of Italy, a European country whose unity of people and cultures was quite a recent event. The possibility of studying genetic differentiation in a small geographical area is tested and trends of genetic differences are tentatively interpreted in terms of historic and linguistic knowledge. The few demographic pieces of information taken from historical sources and compared with linguistic records support the hypothesis that the genetic structure of Italy still reflects the ethnic stratification of pre-Roman times.

Blood Group Antigens↗
PubMed1988

Mitochondrial DNA polymorphism in four Sardinian villages.

Polymorphism of mitochondrial DNA has been studied in two highland (Desulo, Tonara) and in two lowland (Galtellì, Orosei) Sardinian isolates, formerly subjected to different selective pressure due to malaria, and in 103 individuals from Northern Italy (Bergamo area), where malaria never appeared to be endemic. Two mitochondrial restriction endonuclease patterns (morphs) never described before have been found, one in the Bergamo and Orosei samples, and the other one only in Orosei. Four new mitochondrial types (mitotypes) due to different combinations of morphs have been identified; two of them have been found only in Sardinia, but with such a low frequency that they cannot be defined as typical Sardinian mitotypes. One mitotype (BamHI-morph 3, MspI-morph 4, AvaII-morph 9 and HaeII-morph 1) showed a significantly higher frequency in the highland rather than in the lowland Sardinian villages or in the Bergamo area. Since this mitotype has been found at a relatively high frequency in Central and Southern Italy, while it has been reported to be rare in Caucasians of Central European origin and absent in other ethnic groups (Africans, Chinese, Japanese and Israeli Jews), we suggest it may represent an ancient Mediterranean type. The analysis of these data suggests that drift or other evolutive forces different from malaria might be the major cause of mitochondrial DNA variation in Sardinia.

DNA, Mitochondrial↗
PubMed1987

Further characterization of a model system for the study of human epididymal physiology and its relation to sperm maturation.

Some preliminary speculations about the possible participation of epididymal antigens in sperm function may be supported by the above data. On the one hand, the reduction in the amount of antigens and their abnormal localization on spermatozoa from infertile patients may be coincident with our view about participation of epididymal antigens in the development of zona pellucida binding ability and fertilizing capacity by spermatozoa during maturation. This hypothesis is derived from experiments showing that immature hamster spermatozoa gain their ability to recognize and bind to zona pellucida and to penetrate homologous oocytes when exposed to preparations enriched in androgen-dependent epididymal secretory proteins or preincubated in conditions that favor their interaction with these proteins. Supporting our viewpoint for such a role in humans is evidence showing the progressive development of the ability to interact with hamster denuded oocytes as human spermatozoa pass along the epididymis. On the other hand, the apparent correlation between the loss of epididymal antigens during capacitation and the increased fertilization of human oocytes in vitro may be reminiscent of the removal of a decapacitation or acrosome stabilizing factor known to occur in many species and that must be removed prior to fertilization. Pending further understanding of their physiological role, the androgen-dependent epididymal proteins may become a useful marker of epididymal function and/or of sperm capacitation in humans. Within this context, we wish to stress the potential value of the model system that we have developed for the study of human epididymal physiology.

Epididymis↗
PubMed1987

Risk of iron overload and 'hemochromatosis allele(s)' in patients on maintenance hemodialysis.

In the present study, we have evaluated the relationship between serum ferritin (SF) levels, 'hemochromatosis allele(s)', blood transfusions and iron parenteral administration in 69 hemodialysis patients. We demonstrated significantly higher SF levels in patients with hemochromatosis allele(s) (HA+) than in patients without hemochromatosis alleles (HA-). In addition, HA+ patients who had received blood transfusions up to 15 months prior to the study had SF levels even higher than those without blood transfusions. On the other hand, HA- patients had normal levels of SF, independent of blood transfusions. After intravenous administration of 1 g iron saccharate, SF levels were significantly higher only in HA+ transfused patients. In conclusion, our study demonstrated that HA+ patients are at a higher risk of iron overload and therefore the use of transfusional and/or parenteral iron should be strictly limited.

Adolescent↗
PubMed1987

Abnormal distribution of epididymal antigens on spermatozoa from infertile men.

An antiserum raised against human epididymal proteins associated with ejaculated sperm was used to test the hypothesis that the amount and/or localization of these antigens may be altered in men with infertility. With the use of immunofluorescence we found that in sperm from fertile donors 88.4% of the cells had the antigens localized over the acrosomal cap only and 1.3% had most of the antigens at extraacrosomal sites. Fifteen of the 26 infertile men (P1) studied had a similar relative distribution of antigens, but the remaining 11 patients (P2) had a 38-fold increase in cells with extraacrosomal localization of the antigens (40%, P less than 0.005). Using flow cytometry to quantitate immunofluorescence, content of antigen on sperm from patients from population P1 (680 +/- 60 V X 10(-4)) was not different from that of control (835 +/- 53 V X 10(-4], whereas it was significantly lower in sperm from patients from population P2 (554 +/- 64 V X 10(-4), P less than 0.005). Differences could not be correlated with parameters measured by routine semen analysis. Our results suggest a possible relationship between the decreased amount of epididymal antigens or their altered localization on sperm and the infertility of patients from population P2.

Adult↗
PubMed1986

Mental health care in Southern Italy: application of case-control methodology for the evaluation of the impact of the 1978 psychiatric reform.

A survey to analyse patients' characteristics and the care delivered to them was conducted in several psychiatric facilities, covering the whole range of care offered in the public sector in two regions of Southern Italy. A case-control method of analysis was chosen, and the relative risk estimates (RR), together with their 95% confidence intervals (CI), of being in custodial facilities were computed, comparing patients treated in custodial institutions ('cases') with those in community-based services ('controls') in respect of social and clinical variables. Factors more strongly associated with custodial treatment were: illiteracy (RR = 2.4), unmarried status (RR = 2.4), a history of prolonged illness (RR = 7.6), organic diagnosis (RR = 2.6), previous custodial treatment (RR = 3.9), and expected poor social functioning (RR = 2.4). The suitability and advantages of the case-control method of analysis in the field of psychiatric care evaluation are discussed.

Adult↗
PubMed1986

Surnames in Sardinia. III. The spatial distribution of surnames for testing neutrality of genes.

1. A study on heterogeneity of males' surnames over time and space in the island of Sardinia was carried out using data from consanguineous marriages (1800-1970) and telephone directories (1978). 2. Variation of frequency of surnames over time is barely significant and 10 times lower than that over space, which is very highly significant. 3. For sufficiently frequent surnames the estimate of the Wahlund variance, calculated from chi 2 for heterogeneity in space, is independent of the frequency of a surname: this supplies evidence of neutrality in line with that obtained from the frequency distribution of surnames. 4. The Wahlund variance, W (also called FST), decreases regularly as the average size of the area considered (number of individuals per area, N) increases. The estimate of the parameter beta in the relation W = KN beta could be of interest for the study of population structure. 5. A correction factor of 1/4 must be made on the surnames' variance in consideration of their haploid unisexual transmission. 6. It is suggested that surnames could provide a baseline for estimating the value of Wahlund variance under random genetic drift and hence evaluating whether a gene behaves as selectively neutral. 7. The distribution of the Wahlund variances obtained from two sets of gene frequency data as compared with that obtained in comparable conditions for surnames in the same areas seems to show that most genes behave as neutral, with the exception of a few, with high W values, which presumably have been under different selection pressures in the area examined.

Consanguinity↗
PubMed1986

The HLA system in Italy.

4,902 Italians were typed for HLA-A antigens, 4,721 for HLA-B and 1,503 for HLA-C. The samples, which were composed of unrelated, healthy individuals born in Italy, were used for estimating HLA-A, HLA-B and HLA-C gene frequencies with the maximum-likelihood method. Different Italian regions showed significant differences in the HLA alleles, providing further evidence for the genetic heterogeneity of the Italian population. HLA gene frequencies place continental Italy and Sicily in a position which is similar to that of other Mediterranean populations, whereas the genetic isolation of Sardinia is quite evident. The most significant linkage disequilibrium values found in the Italian population (except for Sardinia) were in agreement with those observed in other Caucasian populations. The difference between Northern and Southern Italy and between continental Italy and Sardinia was emphasized by the linkage disequilibrium values and by the principal-component analysis as well.

Gene Frequency↗
PubMed1986

Genetic markers of cluster headache and the links with the lithium salts therapy.

The existing relationship between genetic markers of the cluster headache and the efficacy of lithium salts therapy was described in the present study. Thirty-five patients suffering from cluster headache, who were already typed for the HLA antigens, were studied. Typing was carried out with the microlymphocytotoxicity technique used by US National Institutes of Health. The patients were treated with lithium carbonate for a period of three months. Three parameters for evaluation of the efficacy of lithium therapy was used: the percentage of improvement, the wake-sleep rhythm and the pupil diameter measurement. The parameters were statistically (Student's t-test) evaluated and it was possible to separate two subgroups of patients: "responders" and "non-responders" to the lithium therapy. The phenotypical frequencies in the two subgroups was analysed using the chi 2 test, Data emerging showed a higher frequency of antigen HLA-B18 (23.8% versus 0%; p less than 0.005 pc less than 0.06) and of antigen HLA-A9 (42.9% versus 14.3%) in the "responders" subgroup. In the "non-responders" subgroup a higher frequency of antigen HLA-A1 (35.7% versus 14.3%) was found.

Adult↗
PubMed1986

Vitamin E supplementation in hemodialysis patients: effects on peripheral blood mononuclear cells lipid peroxidation and immune response.

Lipid peroxidation and vitamin E levels in peripheral blood mononuclear cells (PBMC) were studied in 10 patients on maintenance hemodialysis. Significant increases of PBMC malonyldialdehyde (MDA) were detected, together with low vitamin E levels. After a fifteen-day-course of parenteral vitamin E supplementation, PBMC MDA reverted to normal values, while PBMC vitamin E levels remained lower than controls. In a parallel study an immunological monitoring was performed in the same patients before and after vitamin E supplementation. NK activity and PHA blastogenesis were not influenced by treatment, while a reduction of the number of OKT8+ lymphocytes were observed after vitamin E therapy. It is tempting to speculate that peroxidative damage of PBMC cell membranes in hemodialysis patients could, by impairing their functionality, influence immune responses and expression of functionally relevant membrane determinants.

Adult↗