Biomedical subjects

Luisa Guidi

Publications and source records attributed to Luisa Guidi.

5 recordsLinked to original sources

PubMed2006

Multidetector CT enteroclysis versus barium enteroclysis with methylcellulose in patients with suspected small bowel disease.

The purpose of this study was to evaluate the diagnostic accuracy of multidetector-CT enteroclysis (MDCT-E) versus barium enteroclysis with methylcellulose (BE) in clinically selected patients with suspected small bowel disease. We prospectively studied 52 patients who underwent unenhanced and contrast-enhanced multidetector CT (16 rows) after administration of 2-2.5 l of methylcellulose by naso-jejunal tube. BE was performed after administration of barium 60% w/v (200-250 ml) and methylcellulose (1-2 l). Patients with radiological signs of Crohn's disease were classified into the following subtypes: active, fibrostenotic, fistulising/perforating, reparative or regenerative subtypes. Twenty-eight patients also underwent endoscopy. The radiological prevalent subtype was the active subtype. The sensitivity, specificity and diagnostic accuracy of MDCT-E versus BE was 83%, 100% and 89%, respectively. BE showed five false negative CT cases due to early Crohn's disease; endoscopy confirmed positive cases of the CT and the BE, but showed one false negative case of the BE. Together, MDCT enteroclysis and BE permitted the diagnosis of Crohn's disease in 30 patients, adhesions in one patient, lymphoma in two patients and carcinoid tumours in two patients. In conclusion, MDCT-E permits good representation of pathological patterns. Early stages of Crohn's disease are better evaluated by BE.

Adult↗

PubMed2004

Role of immune responsiveness and DNA repair capacity genes in ageing.

The genetic factors that determine immune responsiveness and DNA repair capacity are reviewed as major elements influencing the life span. Within this framework two sets of new data obtained in mice and humans are reported and discussed. As to the first set, the role of immune response genes was investigated in Biozzi mice genetically selected for high (H) or low (L) antibody response. After 15-20 generations of assortative mating, H and L mice exhibited almost complete intraline homozygosity and interline polymorphism including distinct H-2 haplotypes, such as q in H and s in L mice. In order to analyze the impact of quantitative trait loci (QTL) on the antibody response as well as on the DNA repair capacity in cells of the immune system independently of the selected H-2 haplotype, congenic Hq and Hs as well as Lq and Ls mice were produced and analysed. Both the antibody response and DNA repair capacity were found to be independent of the H-2 haplotype and determined by QTL. As to the second set of data, DNA repair was also studied in irradiated peripheral blood mononuclear cells (PBMC) from ageing humans. The levels of ku 70, ku 80, DNA-PKcs, phosphorylated ku 80 as well as the DNA-binding activity of the ku70/ku 80 heterodimer were determined in the cytoplasmic and nuclear extracts obtained, before and after irradiation, from young and elderly subjects. The results of this study suggest that the decreased DNA repair capacity in PBMC from elderly subjects may be related to impaired migration of the phosphorylated ku 80 from the cytoplasm to the nucleus. This finding helps to elucidate questions related to the impairment of DNA repair during ageing.

Aging↗

PubMed2003

DNA damage recognition and repair capacities in human naïve and memory T cells from peripheral blood of young and elderly subjects.

T cells accumulate genetic damage over time but nai;ve cells display higher genomic stability and longer lifespan as compared to memory cells. We found in nai;ve and memory T cells from young and elderly subjects that DNA damage in unirradiated cells is higher in memory than in nai;ve T cells, and is increased by radiation in both cell types. Repair of the radiation-induced DNA damage was much higher in nai;ve than in memory T cells from young subjects but null in both cell types from elderly subjects. Molecular mechanisms involved in DNA damage recognition and repair were analyzed in both cell subsets from young subjects. The intracellular distribution and amount of the DNA-dependent protein kinase (DNA-PK) complex components (ku 70, ku 80, DNA-PKcs), which are involved in the recognition and repair of DNA breaks caused by ionizing radiations, V(D)J recombination and isotype switching, was assessed in nai;ve and memory T cells from young subjects. While the expression of ku 70 and ku 80 was at comparable levels in both T cell subsets, DNA-PKcs, phosphorylated ku 80, and DNA-binding of ku 70/80 were mostly evident in nai;ve but negligible or absent in memory T cells. These findings may account for the higher genomic stability and longer lifespan of nai;ve as compared to memory human T cells from young subjects.

Adult↗

PubMedDate not supplied

The DNA repair protein ku is involved in gp130-mediated signal transduction events in PBMC from young but not from elderly subjects.

Ku, composed of 70kDa (ku 70) and 86kDa (ku 80) proteins, is the DNA-targeting subunit of the DNA-dependent serine/threonine kinase (DNA-PK), which plays a crucial role in DNA double strand break recognition and repair in mammalian cells. We have investigated the effects of an IL-6-type cytokine (K-7/D-6), known to trigger gp130, on the expression and function of the ku protein in cytoplasmic and nuclear extracts of freshly isolated human peripheral blood mononuclear cells (PBMC) from subjects of different ages. DNA-binding of nuclear ku was found to be increased by cytokine treatment of cells from young donors but only to a negligible extent from elderly subjects. This cytokine effect was correlated with a greater amount of phosphorylated ku 80, rather than increased expression of ku 70 and ku 80 proteins. DNA-binding activity of cytoplasmic ku was hardly discernible, as compared to nuclear ku, in both young and elderly subjects and was unaffected by the cytokine treatment regardless of age. Regarding the mechanisms whereby ku and gp130 signaling are coupled in PBMC, results from co-immunoprecipitation experiments have shown that ku in the cytoplasm of PBMC from young, but not from elderly subjects, is associated with Tyk-2, a kinase involved in signal transduction events after gp130 triggering by IL-6-type cytokines. This association was independent of PHA stimulation. Moreover, the present results indicate that after gp130 signaling both Tyk-2 and ku 80 are phosphorylated, suggesting their activation by K-7/D-6.

Adult↗

PubMedDate not supplied

Small bowel diseases.

The study of small bowel disease is hampered by the organ length and shape. Malabsorption syndromes, small bowel bleeding, intestinal obstruction are analyzed with reference to the clinical characteristics and present laboratory and instrumental tests used in diagnosis. The introduction of sophisticated diagnostic imaging procedures, both endoscopic and radiologic have contributed to a better understanding of the symptomatic patterns.

Diagnostic Imaging↗