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Biomedical subjects

A Cossarizza

Publications and source records attributed to A Cossarizza.

At least 109 records · Page 6Linked to original sources
PubMed1993

50 Hz AC sinusoidal electric fields do not exert genotoxic effects (micronucleus formation) in human lymphocytes.

Electromagnetic fields produce a variety of effects in several biological systems, including human peripheral blood lymphocytes. A great concern exists regarding possible carcinogenic effects in subjects exposed environmentally to such fields in the vicinity of power lines and electric domestic appliances. Using human lymphocytes from 33 healthy donors and a sensitive cytogenetic method, the cytokinesis-block micronucleus assay, we have demonstrated that the exposure to 50-Hz AC sinusoidal electric fields over a wide range of intensities (0.5-10 kV/m in air) does not increase the spontaneous frequency of micronuclei. Moreover, these fields did not affect the mitomycin-C-induced micronucleus formation, suggesting that they did not exert any synergistic or antagonistic effect.

Adult↗
PubMed1993

Polymerase chain reaction in the early diagnosis of HIV-1 infection in high risk subjects.

We investigated the presence of the HIV-1 infection using the polymerase chain reaction (PCR) test in seronegative sexual partners of HIV-infected subjects and in children born to seropositive mothers. By using PCR assay, no HIV-1 DNA was detected in 32 female partners of HIV positive patients including three pregnant women who were also studied during pregnancy and after delivery. HIV-1 DNA was found in 12 out of 38 children born to seropositive mothers; five of them also had detectable serum HIV-1 p24 Ag levels. On the whole, our data stress the importance of using a very sensitive technique, i.e. PCR, for the early diagnosis of HIV-1 infection.

AIDS Serodiagnosis↗
PubMed1992

Inhibition of apoptosis by zinc: a reappraisal.

Apoptosis--or programmed cell death--is an active type of cell death, occurring in several pathophysiological conditions. One of the most important characteristics of apoptosis is that cell death is preceded by DNA fragmentation, consequent to the activation of nuclear calcium- and magnesium-dependent endonuclease(s). DNA fragmentation can be inhibited by zinc ions. By using several techniques, such as DNA agarose gel electrophoresis, cytofluorimetric analysis of DNA content and of cell cycle, 3H-thymidine incorporation and trypan blue dye exclusion test, we show that zinc, despite completely inhibiting DNA fragmentation and the consequent loss of nuclear DNA content, does not protect rat thymocytes from spontaneous or dexamethasone-induced death. Our data also suggest that DNA fragmentation, although characteristic, is not a critical event for thymocyte death of apoptotic type.

Animals↗
PubMed1992

Thyroid and other organ-specific autoantibodies in healthy centenarians.

To investigate the prevalence of thyroid autoantibodies in very old subjects, we assayed sera from 34 healthy centenarians (7 men, 27 women; age range 100-108 years) for these antibodies. There was a clear age-dependent increase in prevalence of thyroid autoantibodies in sera from 549 control subjects aged 7-85 years, prevalence in 40 subjects aged 70-85 being significantly greater (p less than 0.001, chi 2) than that in 436 subjects aged less than 50. By contrast, prevalence of thyroid autoantibodies in centenarians was not significantly different from that in controls aged less than 50. Cytofluorimetric analysis of peripheral blood lymphocytes showed a striking age-dependent decrease in total and CD5+B cells (without changes in their ratio), which reached its nadir in centenarians. The age-dependent increase in prevalence of thyroid autoantibodies in the elderly is not seen after the ninth decade of life. What relation this characteristic has to derangement of circulating B cells is unknown.

Adolescent↗
PubMed1992

Selective deficiency of CD4+/CD45RA+ lymphocytes in patients with ataxia-telangiectasia.

Several immunological abnormalities have been observed in ataxia-telangiectasia (AT), the most consistent being defects of immunoglobulin isotypes, decreased T-cell numbers, and reduced proliferative responses to mitogens. We examined the distribution of T lymphocytes expressing distinctive surface Ag characteristic of "naive" (CD45RA+) and "memory" (CD29+, CD45RO+) T cells, in both CD4+ and CD8+ (bright and dim) lymphocytes from 13 AT patients, compared with healthy age-matched controls. We found that, irrespective of age, patients with AT had a severe deficiency of CD4+/CD45RA+ lymphocytes. This decrease accounted for the reduction of total CD4+ cells, since the absolute numbers of memory CD4+ cells were not significantly different in AT and in controls. Functional tests revealed poor proliferative responses to phytohemagglutinin and normal responses to soluble Ag (tetanus toxoid) in AT patients. These data fit with the distribution of naive and memory cells, which are known to respond predominantly to mitogens or to recall Ag, respectively. CD45RA molecules were normally expressed on CD8+ lymphocytes. This rules out a generalized defect of regulation or differential splicing as the cause of defective expression of CD45RA on CD4+ cells. The selective deficiency of CD4+CD45RA+ may provide a cellular basis for some functional T-cell abnormalities of AT patients. Furthermore, it might practically serve for an early, or even prenatal, diagnosis of this disease.

Adolescent↗
PubMed1992

ACTH-like molecules in lymphocytes. A study in different vertebrate classes.

Immunocytochemical and cytofluorimetric studies were performed in several species of different classes (Pisces, Amphibia, Reptilia and Aves), in order to ascertain the presence of ACTH-like molecules in blood cells. Using monoclonal and polyclonal antibodies, we demonstrated that lymphocytes containing ACTH-like molecules are first detectable in anuran amphibia, and are present in lymphocytes of reptilia and aves. Taking into account previous results demonstrating that ACTH-like molecules are present in and modulate macrophage functions from molluscs to man, it is argued that a new biological role has probably been acquired by ACTH in higher vertebrates, where it is also expressed in cells belonging to the lymphocyte lineage, possibly exerting a regulatory role on antibody response.

Adrenocorticotropic Hormone↗
PubMed1992

Apoptosis--programmed cell death: a role in the aging process?

Cells continuously exposed to genotoxic agents, such as oxygen free radicals (OFRs), deeply involved in the aging process use a variety of cellular defense mechanisms. These defense mechanisms include DNA repair enzymes, antioxidants, poly(ADP-ribosyl)polymerase (pADPRP), and stress proteins and they constitute an integrated network. An age-related failure of the efficiency of this network can affect cell proliferation and cell death, two phenomena tightly linked and regulated. Recent data from our laboratory on the role of DNA damage and pADPRP activation and on the type of cell death induced by OFRs in human lymphocytes are reviewed. In vitro and in vivo data on possible strategies to reduce oxidative stress in lymphocytes from normal and Down syndrome subjects, by using natural compounds and trace elements, are presented. They indicate that nicotinamide and L-carnitine protect human cells from OFR-induced damage and suggest that they are possible candidates as antiaging substances.

Aging↗
PubMed1992

Lymphocytes and low-frequency electromagnetic fields.

Human lymphocytes have been used by several researchers to investigate the biological effect of electromagnetic fields (EMF). EMF modulate the response by lymphocytes to lectin stimulation. The size and direction of the effect depends both on the lymphocyte physiology and on the physical parameters characterizing the EMF. Lymphocytes have also been used to investigate the genotoxicity of EMF exposure.

Electromagnetic Fields↗
PubMed1992

Changes in circulating B cells and immunoglobulin classes and subclasses in a healthy aged population.

The study of 87 adults of different ages, including 15 centenarians, selected for their healthy status, showed that profound changes of humoral immunity occur throughout life. In particular, a statistically significant age-related increase of the serum level of immunoglobulin classes (IgG and IgA but not IgM) and IgG subclasses (IgG1, 2 and 3, but not IgG4) was detected. A parallel age-related decrease of circulating B cells was also observed. The hypothesis of a complex derangement of B cell function and/or compartmentalization with age is put forward, together with the proposal that healthy centenarians (as representative of successful ageing) may be helpful in identifying the physiological age-related modifications of the immune system.

Adult↗
PubMed1992

Cytotoxicity and cell death: studies on molluscan cells and evolutionary considerations.

In a previous study we demonstrated the presence of NK-like activity in the mollusc Planorbarius corneus. This activity can be ascribed to round hemocytes that have a morphology similar to that of vertebrate lymphocytes. We show here that this NK-like cytotoxicity is evident in serum-free culture medium. Moreover, the type of death induced by molluscan effector cells on their targets is probably similar to that induced by vertebrate effector cells, i.e. apoptosis or programmed cell death, as assessed by the protective effect exerted by 3-aminobenzamide when both types of effector cells were used.

Animals↗
PubMed1991

ACTH-like molecules in gastropod molluscs: a possible role in ancestral immune response and stress.

The presence of immunoreactive ACTH molecules on phagocytic cells from the freshwater snails Planorbarius corneus and Lymnaea stagnalis was shown by cytofluorimetric analysis. The role of ACTH in phagocytosis and in the release of biogenic amines, two biological responses that may be taken as ancestral types of immune response and stress, respectively, has also been evaluated. ACTH markedly increased the phagocytosis of Staphylococcus aureus by P. corneus haemocytes and caused the release of biogenic amines from such cells into the serum. These data, as well as tracing the ancestral physiological role of ACTH, favour the hypothesis that immune and neuroendocrine systems share a common evolutionary origin.

Adrenocorticotropic Hormone↗
PubMed1991

Spontaneous and mitomycin-C-induced micronuclei in human lymphocytes exposed to extremely low frequency pulsed magnetic fields.

The cytokinesis block micronucleus method, a very sensitive cytogenetic assay, was used to ascertain the possible genotoxic effects of extremely low frequency pulsed magnetic fields in phytohemagglutinin-stimulated human lymphocytes cultures from 16 healthy donors. Four conditions were studied: i) lymphocytes not exposed to the field (control cultures); ii) lymphocytes exposed to the field; iii) lymphocytes treated with mitomycin-C and not exposed to the field; iv) lymphocytes treated with mitomycin-C and exposed to the field. Mitomycin-C-treated cultures were used as control for the micronucleus method, because it is known that mitomycin-C is a potent genotoxic agent, capable of inducing micronuclei. The frequency of micronuclei in field-exposed cultures was similar to the spontaneous frequency observed in control unexposed-cultures. Moreover, the exposure to pulsed magnetic fields did not affect the frequency of micronuclei induced by mitomycin-C, suggesting that, in the experimental conditions used, this kind of field neither affected the integrity of chromosomes nor interfered with the genotoxic activity of mitomycin-C.

Alkylating Agents↗
PubMed1991

Age-related expansion of functionally inefficient cells with markers of natural killer activity in Down's syndrome.

Peripheral blood lymphocyte subsets of two groups of patients affected by Down's syndrome (DS), ie, 28 children and nine adults of relatively advanced age (greater than 34 years), were investigated and compared with those of age- and sex-matched healthy controls (13 children and 20 adults). Particular attention was devoted to cells with markers of natural killer (NK) activity. Double- and triple-color cytofluorimetric analysis was used to better characterize the phenotypic features of the different subsets. Apart from a reduced number of T lymphocytes (CD3+) in DS children and of B lymphocytes (CD19+) in both DS groups, the major alteration we found was a marked age-related increase of the percentage of cells bearing markers associated with NK activity, such as CD16, CD56, and CD57. These DS cells were apparently severely defective as far as their function was concerned, because NK activity was significantly reduced in comparison with age-matched controls, but still capable of responding to cytokines such as interleukin-2, interferon-beta, and interferon-gamma, and to the modulation of lytic activity exerted by the anti-CD16 monoclonal antibody. On the whole, our data stress the importance of studying DS subjects of different ages to fully appreciate the immunologic derangement characteristic of this syndrome.

Adolescent↗