Biomedical subjects

Alessandra Stella

Publications and source records attributed to Alessandra Stella.

9 recordsLinked to original sources

PubMed2026

Cross-kingdom dynamics of the subgingival bacteriome and mycobiome: A pilot study on the effects of a novel HA-H₂O₂-Glycine formulation to treat periodontitis.

OBJECTIVES: Traditional periodontal therapy primarily focuses on bacterial biofilm control; however, recent evidence also suggests a critical role for the oral mycobiome. This study evaluated the clinical and ecological impact of a novel mouthwash formulation containing hyaluronic acid (HA), hydrogen peroxide (H2O2), and glycine on periodontal patients METHODS: This prospective, randomized split-mouth trial included 13 adult participants with periodontitis treated with HA-H2O2-glycine formula (BMG0703A) used twice a day for seven days. Subgingival plaque samples were collected from periodontal pocket and healthy control sites at baseline (T0) and one-week post-treatment (T1). Microbial and fungal communities were characterized using Next-Generation Sequencing (NGS) of the 16S rRNA and ITS2 regions. Linear Mixed Models (LMM) and Spearman correlation were used to assess taxonomic shifts and cross-kingdom relationships. RESULTS: Sequencing revealed a promising ecological shift: the bacteriome shifted from anaerobic dominance (Olsenella, Peptostreptococcus) toward a health-associated aerobic profile, with Rothia near-doubling (11.91% to 22.68%). The mycobiome underwent a "normalization" effect: Candida abundance decreased significantly (22.8% to 9.1%), while fungal Shannon diversity in pockets returned to healthy-site levels. Inter-kingdom analysis identified antagonistic relationships between expanding commensal bacteria and opportunistic fungi, suggesting that the intervention may help re-establish a protective bacterial niche. CONCLUSIONS: The HA-H2O2-glycine formulation seems to facilitate a rapid, cross-kingdom modulation of the subgingival niche. By reducing anaerobic pathogens and normalizing the mycobiome it appear to induce short-term changes, suggesting potential as adjunctive strategy in periodontal management. CLINICAL SIGNIFICANCE: The present work underlines the possible cross-Kingdom effects of a novel compound.

Humans↗

PubMed2007

Spatiotemporal analysis of the cortical sources of the steady-state visual evoked potential.

This study aimed to characterize the neural generators of the steady-state visual evoked potential (SSVEP) to repetitive, 6 Hz pattern-reversal stimulation. Multichannel scalp recordings of SSVEPs and dipole modeling techniques were combined with functional magnetic resonance imaging (fMRI) and retinotopic mapping in order to estimate the locations of the cortical sources giving rise to the SSVEP elicited by pattern reversal. The time-varying SSVEP scalp topography indicated contributions from two major cortical sources, which were localized in the medial occipital and mid-temporal regions of the contralateral hemisphere. Colocalization of dipole locations with fMRI activation sites indicated that these two major sources of the SSVEP were located in primary visual cortex (V1) and in the motion sensitive (MT/V5) areas, respectively. Minor contributions from mid-occipital (V3A) and ventral occipital (V4/V8) areas were also considered. Comparison of SSVEP phase information with timing information collected in a previous transient VEP study (Di Russo et al. [2005] Neuroimage 24:874-886) suggested that the sequence of cortical activation is similar for steady-state and transient stimulation. These results provide a detailed spatiotemporal profile of the cortical origins of the SSVEP, which should enhance its use as an efficient clinical tool for evaluating visual-cortical dysfunction as well as an investigative probe of the cortical mechanisms of visual-perceptual processing.

Adolescent↗

PubMed2006

Genomic-assisted prediction of genetic value with semiparametric procedures.

Semiparametric procedures for prediction of total genetic value for quantitative traits, which make use of phenotypic and genomic data simultaneously, are presented. The methods focus on the treatment of massive information provided by, e.g., single-nucleotide polymorphisms. It is argued that standard parametric methods for quantitative genetic analysis cannot handle the multiplicity of potential interactions arising in models with, e.g., hundreds of thousands of markers, and that most of the assumptions required for an orthogonal decomposition of variance are violated in artificial and natural populations. This makes nonparametric procedures attractive. Kernel regression and reproducing kernel Hilbert spaces regression procedures are embedded into standard mixed-effects linear models, retaining additive genetic effects under multivariate normality for operational reasons. Inferential procedures are presented, and some extensions are suggested. An example is presented, illustrating the potential of the methodology. Implementations can be carried out after modification of standard software developed by animal breeders for likelihood-based or Bayesian analysis.

Algorithms↗

PubMed2005

ESTree db: a tool for peach functional genomics.

BACKGROUND: The ESTree db http://www.itb.cnr.it/estree/ represents a collection of Prunus persica expressed sequenced tags (ESTs) and is intended as a resource for peach functional genomics. A total of 6,155 successful EST sequences were obtained from four in-house prepared cDNA libraries from Prunus persica mesocarps at different developmental stages. Another 12,475 peach EST sequences were downloaded from public databases and added to the ESTree db. An automated pipeline was prepared to process EST sequences using public software integrated by in-house developed Perl scripts and data were collected in a MySQL database. A php-based web interface was developed to query the database. RESULTS: The ESTree db version as of April 2005 encompasses 18,630 sequences representing eight libraries. Contig assembly was performed with CAP3. Putative single nucleotide polymorphism (SNP) detection was performed with the AutoSNP program and a search engine was implemented to retrieve results. All the sequences and all the contig consensus sequences were annotated both with blastx against the GenBank nr db and with GOblet against the viridiplantae section of the Gene Ontology db. Links to NiceZyme (Expasy) and to the KEGG metabolic pathways were provided. A local BLAST utility is available. A text search utility allows querying and browsing the database. Statistics were provided on Gene Ontology occurrences to assign sequences to Gene Ontology categories. CONCLUSION: The resulting database is a comprehensive resource of data and links related to peach EST sequences. The Sequence Report and Contig Report pages work as the web interface core structures, giving quick access to data related to each sequence/contig.

Chromosome Mapping↗

PubMed2005

Genetic analysis of anal atresia in pigs: evidence for segregation at two main loci.

Anal atresia is a relatively common congenital malformation that occurs in about 1 out of 5000 infants, caused by abnormal hindgut development of the embryo, often associated with other developmental anomalies (e.g., Currarino, Townes-Brock, Pallister-Hall syndromes, and VATER association). Genetic analysis in human families is exceedingly difficult due to the multifactorial nature of the trait. In pigs, anal atresia occurs at a higher incidence (0.18%) than in humans. A complete genome scan (165 microsatellite markers) was performed using a backcross pedigree previously obtained by crossing affected animals from a partially inbred line, selected for a high incidence of anal atresia, with an unaffected male of a different breed (Meishan). The data set was analyzed with classical linkage (TWOPOINT) and nonparametric genetic methods (NPL, Non-Parametric Linkage, and TDT, Transmission Disequilibrium Test). Both methods support association of the trait with two loci on Chromosomes 9 and 15. GLI2 (GLI-Kruppel family member GLI2) was identified as a positional candidate gene based on comparative mapping; radiation hybrid mapping confirmed that this locus is located within the QTL region.

Animals↗

PubMed2005

Haplotype analysis of carnitine transporters and left ventricular mass in human essential hypertension.

OBJECTIVE: The carnitine-associated alteration of myocardial fatty acid metabolism may be one of the molecular mechanisms underlying left ventricular hypertrophy (LVH) in essential hypertension. We tested the hypothesis that polymorphisms of the genes involved in carnitine transport, OCTN2, CPT1A, CPT1B, and CPT2, might be associated with LVH. DESIGN: Haplotype-based association analysis in an observational study. SETTING: Outpatients from the Nephrology Division of the University Hospital. PATIENTS: A total of 215 never-treated, middle-aged patients with mild essential hypertension. METHODS: Relationships between left ventricular mass index (LVMI) (measured with m-mode echocardiography) and haplotype combinations for 13 common genetic variants selected from single nucleotide polymorphism database (dbSNPs). RESULTS: The SNPs were selected to cover the genomic region of the four loci, and a total of 23 haplotypes were identified: 8 for OCTN2 (H1 to H8), 8 for CPT1A (H9 to H16), 3 for CPT1B (H17 to H19), and 4 for CPT2 (H20 to H23). In a multilocus haplotype analysis, after adjusting for sex, age, systolic blood pressure, diastolic blood pressure, body mass index, and duration of hypertension, a significant effect on LVMI was seen for H13 (+8.9, P = .05), H14 (-5.63, P = .05), H15 (-18.79, P = .0006), H18 (-1.66, P = .03), and H22 (-3.42, P = .004). These significant haplotypes were respectively 3.7%, 1.6%, 1.6%, 39.3%, and 29.7% of the total population. CONCLUSIONS: These results identify the carnitine-transporter gene family as candidate modifiers of LVMI in human hypertension. The use of common SNPs to define informative haplotypes associated with the phenotype of interest is the starting point for progress toward identification of the trapped contributing SNP(s).

Adult↗

PubMed2005

Role of the adducin family genes in human essential hypertension.

OBJECTIVE: In both humans and rats, polymorphisms of the alpha adducin (ADD1) gene are involved in renal sodium handling, essential hypertension and some of its organ complications. Adducin functions within cells as a heterodimer composed of various combinations of three subunits that are coded by three genes (ADD1, 2, 3) each located on a different chromosome. DESIGN: These characteristics provide the biochemical basis for investigating epistatic interactions among these loci. METHODS: We examined the three adducin gene polymorphisms and their association with ambulatory blood pressure (ABPM) and with plasma levels of renin activity (PRA), endogenous ouabain (EO), in 512 newly discovered and never-treated hypertensive patients. RESULTS: Relative to carriers of the wild type (Gly/Gly) ADD1 gene, patients carrying the mutated Trp ADD1 allele had higher blood pressure (systolic blood pressure (SBP) 143.2 +/- 1.0 versus 140.6 +/- 0.6 mmHg P = 0.027 and diastolic blood pressure (DBP) 94.2 +/- 0.77 versus 92.3 +/- 0.5 mmHg, P = 0.03), lower PRA and EO, consistent with the hypothesis of the renal sodium retaining effect of the Trp allele. Polymorphisms in the ADD2 and ADD3 genes taken alone were not associated with these variables. However, the differences in SBP and DBP between the two ADD1 genotypes were greatest in carriers of the ADD3 G allele (around + 8 mmHg). The significance of the interaction between ADD1 and ADD3 ranged between P = 0.020 to P = 0.006 according to the genetic model applied. CONCLUSIONS: The interaction of ADD1 and ADD3 gene variants in humans is statistically associated with variation in blood pressure, suggesting the presence of epistatic effects among these loci.

Adult↗

PubMed2004

Optimal designs for linkage disequilibrium mapping and candidate gene association tests in livestock populations.

Simulation was used to evaluate the performance of different selective genotyping strategies when using linkage disequilibrium across large half-sib families to position a QTL within a previously defined genomic region. Strategies examined included standard selective genotyping and different approaches of discordant and concordant sib selection applied to arbitrary or selected families. Strategies were compared as a function of effect and frequency of QTL alleles, heritability, and phenotypic expression of the trait. Large half-sib families were simulated for 100 generations and 2% of the population was genotyped in the final generation. Simple ANOVA was applied and the marker with the greatest F-value was considered the most likely QTL position. For traits with continuous phenotypes, genotyping the most divergent pairs of half-sibs from all families was the best strategy in general, but standard selective genotyping was somewhat more precise when heritability was low. When the phenotype was distributed in ordered categories, discordant sib selection was the optimal approach for positioning QTL for traits with high heritability and concordant sib selection was the best approach when genetic effects were small. Genotyping of a few selected sibs from many families was generally more efficient than genotyping many individuals from a few highly selected sires.

Alleles↗

PubMedDate not supplied

The combined use of embryos and semen for cryogenic conservation of mammalian livestock genetic resources.

The objective of this empirical simulation study was to evaluate the use of a combination of semen and embryos in the creation of gene banks for reconstruction of an extinct breed. Such an approach was compared for banks with varying proportions of embryos on the basis of the amount of the material to be stored, time for reconstruction, maintenance of genetic variability, and probability of failure during reconstruction. Four types of populations were simulated, based on reproductive rate: single offspring, twinning, enhanced reproduction, and litter bearing. Reconstruction was simulated for banks consisting of different combinations of semen and reduced numbers of embryos (expressed as a percentage of the material needed for a bank containing exclusively embryos and ranging from 10 to 90%). The use of a combination of semen and embryos increased the number of insemination cycles needed for reconstruction and the level of genetic relatedness in the reconstructed population. The risk for extinction was unacceptably high when a very low proportion of embryos (<20%) was used. However, combining semen with embryos could decrease costs, allowing for the conservation of more breeds, and specific strategies for semen use could decrease the level of relationships in the reconstructed breed.

Animals↗