Search PubMed⌕ Search

Biomedical subjects

G De Benedictis

Publications and source records attributed to G De Benedictis.

At least 19 recordsLinked to original sources
PubMed1997

DNA multiallelic systems reveal gene/longevity associations not detected by diallelic systems. The APOB locus.

To identify possible genetic factors affecting human longevity we compared allele pools at two candidate loci for longevity between a sample of 143 centenarians (S) and a control sample of 158 individuals (C). The candidate loci were APOB and TPO, which code for apolipoprotein B and thyroid peroxidase, respectively. Both restriction fragment length (RFL) (XbaI2488 and EcoRI4154) and variable number of tandem repeat (VNTR) (3'APOB-VNTR) polymorphisms were analysed at the APOB locus; the TPO-VNTR polymorphism (intron 10) was analysed at the TPO locus. The main result of the investigation was that there is an association between the APOB locus and longevity that is revealed only when multiallelic polymorphisms are considered. In particular: (i) the frequency of 3'APOB-VNTR alleles with fewer than 35 repeats is significantly lower in cases than in controls; (ii) the linkage disequilibrium between the XbaI-RFLP and the EcoRI-RFLP is significantly different from 0 in cases but not in controls; (iii) the EcoRI-RFLP and XbaI-RFLP allele frequencies do not discriminate between cases and controls. The differences observed between case and control allele pools are specific to the APOB locus, since no significant difference was observed at the TPO locus.

Adult↗
PubMed1996

Linkage disequilibrium studies in the thyroid peroxidase and apolipoprotein B genes.

Linkage disequilibria in the apolipoprotein B (APOB) gene (EcoRI RFLP/3' APOB VNTR) and in the thyroid peroxidase (TPO) gene (AcyI RFLP/TPO VNTR) were investigated in a sample of 100 individuals from southern Italy. By recoding multiallelic data as diallelic data, each RFLP-VNTR system showed linkage disequilibrium significantly different from zero (EcoRI RFLP/3' APOB VNTR: p < 0.001; AcyI RFLP/TPO VNTR: p < 0.025), thus suggesting that the VNTR arrays are stable. Furthermore, the relationship between the 3' APOB (2p24-p23) and TPO (2pter-p24) VNTR multiallelic systems was also analyzed. The two VNTR polymorphisms were found to be in linkage equilibrium, thus indicating that they can be used together in forensic casework.

Apolipoproteins B↗
PubMed1996

Allele frequency distributions at seven DNA hypervariable loci in a population sample from Calabria (southern Italy).

Genotype and allele frequencies at seven Variable Number of Tandem Repeats (VNTR) loci currently used for forensic purposes have been estimated in a population sample from Calabria (south Italy). DNA target regions relevant to four microsatellites (THO.1; REN.4; D12S67; DYS19) and three minisatellites (D1S80; 3'APOB; TPO.10) were amplified by Polymerase Chain Reaction (PCR) and analysed by electrophoresis and ethidium bromide or silver staining. For all loci, the observed genotypes were found to be in agreement with those expected by the Hardy-Weinberg equilibrium. Data on allele frequencies were in line with those found in sample groups from northern or central Italy, tested for some of the above polymorphisms.

Adolescent↗
PubMed1995

DYS19, D12S67, and D1S80 polymorphisms in population samples from southern Italy and Greece.

Genotype and allele frequencies of the DYS19, D12S67, and D1S80 highly polymorphic loci were determined in population samples from southern Italy (103 subjects) and Greece (84 subjects) using the amplified fragment length polymorphism (AFLP) technique (polymerase chain reaction followed by native PAGE and silver staining). Five, eleven, and eighteen alleles were found at the DYS19, D12S67, and D1S80 loci, respectively. PIC values ranged from 0.55 (DYS19 locus in Italians) to 0.79 (D12S67 locus in Italians). The distribution of D12S67 and D1S80 genotypes conformed to Hardy-Weinberg equilibrium, as confirmed by three statistics. Heterogeneity G tests, carried out on allele frequency distributions, showed a significant difference between the samples at the DYS19 locus, whereas no difference was found with regard to the other polymorphisms. Using data from the literature, we widened the comparison to other European groups analyzed for the same markers. All the polymorphisms were found to distinguish between populations of the same main ethnic group. In particular, D1S80 allele frequencies distinguished the Finns from other European groups (Spanish, German, Italian, and Greek samples). The reduced assay time, the high polymorphism level, and the ability to distinguish between populations indicate that these markers have potential value in population genetic studies.

Alleles↗
PubMed1993

RFLPs of the APOB gene: comparative study between Greeks and southern Italian peoples.

Restriction fragment length polymorphisms (RFLPs) at codons 2488 (XbaI), 3611 (MspI), and 4154 (EcoRI) of the apolipoprotein B gene were investigated in sample groups from Athens (Greece) and Calabria (southern Italy) to verify whether the distribution of the APOB gene variants in Calabria, where Greek colonization occurred in the eighth century B.C., reflects that of the present Greek population. A sample from Apulia, a southern Italian region having a history different from that of Calabria, was also analyzed. Three specific DNA regions, each containing the polymorphic site, were amplified by polymerase chain reaction on 243 samples, and the restriction data for the three groups were compared. The allelic frequencies of the samples from Apulia and Greece showed variability patterns that agree with those found in Caucasians, whereas the Calabrian sample shows remarkable peculiarities, mainly for the EcoRI RFLP. Linkage disequilibrium analyses of pairs of markers showed strong D linkage values between X-M markers, whereas the D linkage values between M-R markers were too small to be reliably estimated. Last, for both Apulians and Greeks, X-R markers showed linkage disequilibrium, whereas for Calabrians they did not. Estimates of XMR haplotypic frequencies were computed; they were found to be appreciably different between Calabrian and Greek samples, whereas the frequencies in the Apulian sample were approximately midway between those in Calabrians and Greeks.

Apolipoproteins B↗
PubMed1992

Morphometrical investigation of medulloblastoma nuclei by S.A.M. (Shape Analytical Morphometry) software system.

In order to characterize medulloblastomas and to get over the difficulties sometimes encountered in differential diagnosis, a double morphometric procedure has been applied to its nuclei. The first consisted of size measurements (maximum diameter, area and perimeter), the latter is represented by S.A.M. (Shape Analytical Morphometry) software-system specifically implemented to describe shape of biological structure by analytical parameters. Analytical and dimensional parameters submitted to Hotelling's multivariate discriminant analysis gave the best results when used together in convenient discriminant subsets, thereby allowing a good distinction between medulloblastoma in comparison with neuroblastoma, Ewing's tumor, lymphoblastic and lymphocytic lymphoma. These results underline the usefulness of morphometric characterization also for practical diagnostic purposes.

Cell Nucleus↗
PubMed1991

EcoRI-RFLP of the Apo B gene: a study in a sample group from south Italy.

EcoRI restriction analysis at codon 4154 of the Apo B gene was performed in a sample of 90 subjects from southern Italy (sample S), using total blood cell DNA amplified by PCR. A group of 46 subjects from northern Italy (sample N) was also investigated for comparison. Southern Italians showed an incidence of the R2 allele (absence of the cutting site) twice as high as that found in northern Italians (48 v. 21%). By ASPCR the mutation which abolishes the restriction site was confirmed as being G----A at the first base of the 4154 codon of the Apo B gene (Glu----Lys) in both S and N samples. By studying the variability of cholesterolaemia among different EcoRI genotypes in the S sample, it was estimated that the average effect of the R2 allele is to lower serum cholesterol by 8.5 mg/dl.

Alleles↗
PubMed1990

Secondary tumors of the ovary. III. Tumors of the gastrointestinal tract and other sites.

16 cases of secondary ovarian tumors observed from 1977 to 1986, and in which the primary neoplasms involved other organs outside the genital tract or the breast, are studied. The observations concerned 13 metastases of the gastro-intestinal tract cancer (6 typical Krukenberg tumors, 3 "tubular" Krukenberg tumors, and 4 non-Krukenberg tumors), 1 urinary bladder cancer, 1 pancreatic cancer, and 1 tumor of unknown origin (probably an amelanotic melanoma). The histological diagnosis was very difficult in patients with no evidence of the primary malignancy, or in patients in whom the metastases simulate a concomitant primary ovarian tumor. The characteristic histological findings, histochemistry, and immuno histochemistry may suggest a correct diagnosis in most of situations.

Adult↗
PubMed1989

Relation between primary tumor shape and biological behavior in breast cancer.

The aim of this study was to investigate the biological significance of tumor shape in breast cancer by considering the shape not as a casual event but as an expression of the behavior and natural history of the tumor. The shape was studied by an analytical morphometry procedure and was related to axillary metastases, which up to now are the most meaningful prognostic factors in this disease. Fifty cases of infiltrating breast carcinoma (25 N+ and 25 N-) were investigated. The shape, studied on subgross sections of the tumor, was considered as the result of two components: the subtle contour irregularities and the main distortions of the figure. The procedures used allowed us to distinguish and to parametrize these two components in order to submit them to univariate analysis (Student's t test), a principal components analysis and, finally, a multivariate discriminant analysis (Hotelling test). The utilized analytical procedures by work-station S.A.M. (S.A.M. work station is a product of "Metamorphosis") consisted of three steps: 1) Extraction of tumor function curve obtained by Kth order polynominals which gives a smoothing effect to the original curve; 2) Evaluation of contour irregularities by Fourier harmonic analysis; 3) Evaluation of shape asymmetry by SAE (shape asymmetry evaluator). We considered also the roundness factors of the original and function curves and finally the maximum tumor diameter. Three parameters relating to contour irregularities (sum and mean value of Fourier harmonic amplitude and percentage of superimposed points) and parameters relating to main distortions of the figure (mean value of SAE) were highly significant (p less than 0.001). The roundness factor of the original curve was more significant (p less than 0.001) than that of the function curve (p less than 0.01) whereas maximum tumor diameter was not significant when tested by Student's t test. Multivariate discriminant analysis allowed 20% of error to be reached by using 3 parameters relating to the shape analysis and the two roundness factors. By using 8 parameters, including maximum tumor diameter, the percentage error was 16%. The results obtained, while they stress the usefulness of the employed procedure, reveal that shape of the tumor, together with its dimensions, is an important expression of the biological behavior relating to metastatic spread.

Analysis of Variance↗
PubMed1989

Non-Hodgkin's lymphoma diagnosis aided by the S.A.M. system.

In the attempt to discriminate between centroblasts and immunoblasts, an analytical morphometrical procedure was adopted, considering the nuclei of a randomly selected centroblastic and immunoblastic population from non-Hodgkin's lymphomas and the nucleoli of a more restricted number of the same neoplastic population. All the size-independent shape-descriptor parameters extracted for each step of the mathematical analyses used were submitted to Hotelling's multivariate discriminant analysis that enabled us to achieve a good distinction (3% error) between centroblasts and immunoblasts when nuclear and nucleolar parameters were used together.

Cell Nucleus↗
PubMed1989

Mitochondrial DNA polymorphisms in Italy. III. Population data from Sicily: a possible quantitation of maternal African ancestry.

mtDNA polymorphisms were studied in a sample of 90 individuals of the Sicilian population using six restriction enzymes: HpaI, BamHI, HaeII, MspI, AvaII and HincII. (1) Three new patterns, for MspI, AvaII and HincII, have been detected. (2) At least two different mutations were found to account for both the AvaII morph 3 and the AvaII morph 9 as in many other Caucasian groups so far examined. (3) Seventeen types were found; of these six are new. The frequency (54.5%) of type 1-2 (2.1.1.1.1.2) is lower than in the rest of Italy whereas those of type 6-2 (2.1.2.1.1.2) (10.0%) and type 18-2 (2.3.1.4.9*.2) (12.2%) lie at the upper level of the Italian range. The 18-derivative, type 57-2 (2.3.1.4.13*.2), which is consistently found in all Italian samples, is present also among Sicilians with an incidence of 2.2%. (4) Of particular interest is that the HpaI-3/AvaII-3 complex, which is unique to groups of African ancestry, was found in Sicily at a frequency of 4.4%. For the first time an estimate of the amount of gene flow from Blacks to the Sicilian gene pool could be obtained.

Africa↗