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Biomedical subjects

G Bologna

Publications and source records attributed to G Bologna.

15 recordsLinked to original sources
PubMed2001

A study on rule extraction from several combined neural networks.

The problem of rule extraction from neural networks is NP-hard. This work presents a new technique to extract "if-then-else" rules from ensembles of DIMLP neural networks. Rules are extracted in polynomial time with respect to the dimensionality of the problem, the number of examples, and the size of the resulting network. Further, the degree of matching between extracted rules and neural network responses is 100%. Ensembles of DIMLP networks were trained on four data sets in the public domain. Extracted rules were on average significantly more accurate than those extracted from C4.5 decision trees.

Neural Networks, Computer↗
PubMed2000

Shortage of circulating naive CD8(+) T cells provides new insights on immunodeficiency in aging.

Clinical observations indicate that elderly people are prone to severe, often lethal infectious diseases induced by novel pathogens. Since the ability to mount primary immune responses relies on the availability of naive T cells, the circulating naive T-cell reservoir was evaluated throughout the human life span. Naive T cells were identified as CD95(-) T lymphocytes for their phenotypic and functional features. Indeed, the lack of CD95 marker is sufficient to identify a population of naive T cells, as defined by coincidence with previously characterized CD45RA(+) CD62L(+) T cells. Naive CD95(-) T cells, as expected, require a costimulatory signal, such as CD28, to optimally proliferate after anti-CD3 stimulation. Cytofluorimetric analysis of circulating T lymphocytes from 120 healthy subjects ranging in age from 18 to 105 years revealed that naive T cells decreased sharply with age. The younger subjects had a naive T-lymphocyte count of 825 +/- 48 cells/microL, and the centenarians had a naive T-lymphocyte count of 177 +/- 28 cells/microL. Surprisingly, the naive T-cell count was lower in CD8(+) than in CD4(+) subsets at any age, and the oldest individuals were almost completely depleted of circulating naive CD8(+) T cells (13 +/- 4 cells/microL). Concomitantly, a progressive expansion of CD28(-) T cells occurs with age, which can be interpreted as a compensatory mechanism. These data provide new insights into age-related T-cell-mediated immunodeficiency and reveal some analogies of T-cell dynamics between advanced aging and human immunodeficiency virus (HIV) infection. In conclusion, the exhaustion of the naive CD8(+) T-cell reservoir, which has never been reported before, suggests that this T-cell pool is a major target of the aging process and may define a parameter possibly related to the life span of humans. (Blood. 2000;95:2860-2868)

Adolescent↗
PubMed1997

T lymphocyte proliferative capability to defined stimuli and costimulatory CD28 pathway is not impaired in healthy centenarians.

It is generally assumed that T cell proliferation is impaired in aged individuals. We report data on the proliferative capability of peripheral blood mononuclear cells (PBMC) and T lymphocytes from 40 healthy people of different ages, (19-107 years), including 14 centenarians, to defined mitogenic stimuli. We observed no age-related proliferative impairment both in PBMC and in purified T cells stimulated by anti-CD3 mAb or phorbol myristate acetate (PMA). Furthermore, T cells stimulated by anti-CD3 mAb or PMA and costimulated by CD28 mAb did not proliferate differently among young, middle aged subjects and centenarians. Thus, short term T cell proliferation is not affected even at extreme age when well defined stimuli are used on cells deriving from carefully selected healthy subjects.

Adult↗
PubMed1997

A double-blind, placebo-controlled study of preventive immunotherapy with E.P.D., in the treatment of seasonal allergic disease.

Control of seasonal symptoms by means of a preventive and easy to use (only one intradermal injection eight weeks before the pollen peak) immunotherapy, is recommended nowadays. We verified the clinical efficacy of E.P.D. (Enzyme Potentiated Desensibilization) in a double-blind, placebo-controlled study. This particular immunotherapy consists of an intradermal injection mix, made up of allergenic extracts at extremely low doses and an enzyme called beta-glucuronidase. The vaccine is administered once a year, eight weeks before pollen peaks. We studied a group of 40 patients allergic to grass pollen. The results, analysed statistically on the basis of a symptoms score, showed good clinical efficacy and a significant reduction of drug consumption during the high pollen period. Due to the clinical effectiveness, easy administration (only on injection) and excellent tolerance of the immunotherapy, E.P.D. is particularly suited for the prevention of seasonal symptoms in patients allergic to grass pollen.

Adjuvants, Immunologic↗
PubMed1996

Expansion of cytotoxic CD8+ CD28- T cells in healthy ageing people, including centenarians.

Ageing is associated with complex remodelling in the phenotypic and functional profiles of T lymphocytes. We investigated whether expression of CD28 antigen on T cells is conserved throughout adulthood and ageing in humans. For this purpose we analysed T cells obtained from peripheral blood of 102 healthy people of ages ranging from 20 to 105 years. We found an age-related increase of CD28- T cells in percentage and absolute number, predominantly among CD8+ T cells. CD28- T cells from aged donors analysed by flow cytometry appeared as resting cells (not expressing CD25, CD38, CD69, CD71, DR), bearing markers of cytotoxic activity (CD 11b and CD 57) and with a phenotype compatible with 'memory' cells (up-regulated CD2 and CD11a; CD62L absent). At the functional level, freshly isolated purified CD28- CD8+ T cells showed high anti-CD3 redirected cytotoxic activity against Fc-bearing P815 cells. The same activity tested on freshly isolated bulk T lymphocytes was significantly augmented with age. We found a positive correlation between age, number of CD8+ CD28- T cells and anti-CD3 redirected cytotoxicity by freshly isolated T cells. These data suggest that an activation of unknown nature within the cytotoxic arm of the immune system occurs with age. We speculate that these cytotoxic T lymphocytes (CTL) in vivo may constitute armed effector cells for immediate killing of targets bearing peptides from pathogens of intracellular origin.

Adult↗
PubMed1990

Morphometric evaluation of CD16-positive cells with respect to CD2 antigen coexpression.

We examined morphometric as well as functional characteristics of CD16-positive human peripheral blood lymphocytes on the basis of the coexpression of the CD2 antigen. For morphometric analyses, nuclear area and cellular area were determined by counting line cross-points of a superimposed quadratic lattice test system overlying nuclei and the whole cell, respectively. Moreover, to evaluate the cellular villousity degree, the maximum inscrible circle and an irregular polygon were inscribed within cell profiles. The cytoplasm fraction included between the plasmalemma and the traced irregular polygon was considered as the villous portion of the cell. Finally, the NK capability was measured in a 6-hr 51Cr-release assay with human K-562 myeloid cells as targets. Within the CD16-positive cell population, the CD16-positive/CD2-negative cells seem to represent the most efficient NK cell subset. To the higher NK capability correspond a higher villousity degree and a lower nuclear area/cellular area ratio of the CD2-negative/CD16-positive subset, when compared with CD2-positive/CD16-positive cells.

Antibodies, Monoclonal↗
PubMed1987

Study of e+

Explore the source record for details and available documents.

Journal Article↗
PubMedDate not supplied

[Multiple symmetrical lipomatosis (MSL): a clinical case and a review of the literature].

Multiple symmetric lipomatosis (MSL) is a rare condition of the fatty tissue affecting mostly white men between 20 and 65 years old especially in the mediterranean region. The disease is characterized by a massive development of large unencapsulated lipomas mainly located on the subcutaneous tissue of the cervical, deltoid, thoracic, abdominal and lumbar areas and it is often accompanied by hyperuricemia, dyslipemia, macrocytic anaemia, peripheral neuropathy, impaired glucose tolerance and alcohol consumption. Alcohol could both promote the development of lipomas through changes in the number and function of beta-adrenergic receptors and because of its lipogenic and antilipolytic action. Other authors have hypothesized that the defective lipolysis is due to a disorder in the mitochondria of brown fat whose distribution is similar to the peculiar position of the lipomas in the MSL. In this report the authors describe an atypical clinical picture of MSL in a 65-years-old white man.

Aged↗