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Biomedical subjects

S Nuti

Publications and source records attributed to S Nuti.

28 records · Page 2Linked to original sources
PubMed1990

Investigation of rat mast cell degranulation using flow cytometry.

Mast cells degranulation has been assessed by flow cytometry (FACS) taking advantage of the changes in the light scattering properties of mast cells stimulated by secretagogues. In turn, these changes are based on the modification of size, shape, and granule content of the cells before and after stimulation. With FACS, it is possible to work with almost pure mast cell populations (greater than 99%). Moreover, responses to compound 48/80 are carried out in real time and on the same cell sample that acts as internal control. This technique is very sensitive as shown by the ED50 of compound 48/80 (0.051 micrograms/mL) compared to its ED50 on histamine release (0.131 micrograms/mL). The well-known inhibitory effect of disodium cromoglycate against compound 48/80 was clearly observed using FACS. Furthermore, FACS allowed to distinguish between specific degranulating effects and cytotoxicity. Among the secretagogues used, only the degranulation induced by phospholipase A2 was inhibited by in vivo treatment with dexamethasone. It is suggested that the inhibitory effect is due to induction of phospholipase A2-inhibitory proteins (lipocortins).

Animals↗
PubMed1989

Natural antibacterial activity against Salmonella typhi in human cord blood.

Cord blood mononuclear cells from normal human newborns possess natural antibacterial (NA) activity against Salmonella typhi, as assessed by an in vitro test. NA activity was significantly higher than that observed in PBMC from normal adult donors. Using fractionation on nylon wool and Percoll gradient or C-dependent killing with mAb, it was found that cells of the monocyte-macrophage series and CD4+ T lymphocytes were capable of exerting NA activity in newborns, in contrast with results obtained in adults, where the effector cell was a CD4+ T lymphocyte. The capability of expressing NA activity by CD4+ T lymphocytes from cord blood was also confirmed by flow cytometry sorting. Pretreatment of cord blood mononuclear cells with F(ab')2 fragments against human IgG, but not against human IgA, abrogate the NA activity. Furthermore, human IgA anti-S. typhi cannot arm CD4+ lymphocytes in cord blood. Thus it can be suggested that in newborns, the immune system still being immature, NA activity might be the expression of a mechanism of defence against infections, acting as antibody-dependent cellular cytotoxicity expressed by monocytes and CD4+ T lymphocytes armed with preexisting maternal IgG antibodies. This differs from NA activity of adults which is only mediated by CD4+ T lymphocytes armed by IgA.

Adult↗
PubMed1988

Flow cytometric analysis of DNA ploidy pattern from deparaffinized formalin-fixed gastric cancer tissue.

Histologically processed tissue from gastric cancers has been analyzed by flow cytometry in an attempt to correlate DNA ploidy pattern and behavior of the tumor. Of the mucosal and submucosal cancers (so-called early, all stage I in the present series), 62.7% show a diploid DNA pattern and 37.3% show a single aneuploid pattern. Of the deeply infiltrating (beyond the submucosa) cancers (stage II and III), 52.1% are single aneuploid and 47.9% are multiploid. While stage-I patients are all alive at the end of the follow-up period (6 years), in stage II and III cases Cox's regression model shows that the hazard function depends on DNA pattern: survival is negatively influenced by multiploidy. On this basis, it may be assumed that the DNA pattern is a useful prognostic indicator of gastric cancer. As expected, in Cox's regression model an even more important negative correlation exists between survival and stage: single aneuploid cases in stage II have a better prognosis than those in stage III. Instead, no correlation is found between histological cancer subtype (Laurén and WHO classifications), grade and DNA pattern.

Adult↗
PubMed1988

Dissecting human T cell responses against Bordetella species.

To identify the minimal structures that may be important for the creation of a synthetic and/or recombinant vaccine against whooping cough, human T cell clones were obtained against Bordetella antigens. Cloned peripheral blood T lymphocytes from an immune donor were grown in IL-2 and tested for proliferation in response to inactivated Bordetella species (B. pertussis, B. parapertussis, and B. bronchiseptica) and mutants deficient for the expression of virulence-associated antigens. All the T cell clones obtained were CD4+8- and recognized specifically the Bordetella antigens when presented by autologous B cells. On the basis of the responsiveness to the whole inactivated bacteria, it was possible to cluster the 12 clones obtained into four groups with the following specificity: (1) filamentous hemagglutinin (FHA); (2) B. pertussis-specific antigens; (3) virulence-associated Bordetella-specific antigens; and (4) nonvirulence-associated Bordetella-specific antigens. Using two new B. pertussis deletion mutants, clone 6 (representative of cluster 1) was found to recognize the COOH terminus of FHA. Furthermore, three out of four clones of cluster 3 were specifically stimulated by the soluble 69-kD protein from the outer membrane of B. pertussis. Surprisingly, none of the twelve clones obtained by stimulation in vitro with whole inactivated bacteria recognized pertussis toxin (PT), which is believed to be the most important protein to be included in an acellular vaccine. However, when a new generation of clones was obtained using soluble PT as the in vitro stimulus, it was observed that 11 clones of this group recognized this antigen. Thus, PT does not seem to be the most representative antigen on the whole inactivated bacteria, although T cell memory against PT exists in a donor who had the disease several years ago.

Adult↗
PubMed1988

Flow-cytometric assessment of DNA index and percent S phase cells in bronchogenic epidermoid carcinoma.

The DNA index and percent S phase cells were assessed in 45 bronchogenic epidermoid carcinomas from paraffin-embedded retrieved material by flow cytometry. Previously, a comparison between flow cytometric findings from fresh and from paraffin-embedded material was made. The DNA index and the percent S phase cells from fresh and paraffin-embedded material were strongly correlated. Only 3 of the 45 cases were diploid. The DNA index was significantly lower in grade 1 than in grade 2-3 tumors. No correlations were found between DNA index and presence of lymph node metastases, but the percent S phase cells was significantly higher in lymph-node-positive tumors.

Carcinoma, Bronchogenic↗
PubMed1983

Cerebral malaria treated with high doses of chloroquine.

Data concerning 11 cases of cerebral malaria treated with high doses of chloroquine base (18mg/kg/day) are reported. The risk of chloroquine resistance (already described in Tanzania) and the fact that only chloroquine is available on the island of Pemba, were the reasons for increasing the usual dose. High doses clinically seem to offer better results, only one of 11 dying (9.1%) compared with four of 30 (13.3%) in the control group given normal doses. However, the lack of significant differences between the two groups and the greater risk with high doses of chloroquine may not always justify their use to overcome a RI chloroquine resistance in adults and adolescents.

Adolescent↗
PubMed1968

Oxygen-isotope ratios in phosphate from fossil marine organisms.

Well-preserved fossil marine organisms generally yield very positive delta(18)(PO(4)(3-)) values which are considered to result from relatively good preservation of the original oxygen-isotope composition of phosphatic material deposited under isotopic equilibrium conditions in oceanic water whose O(18):O(16) ratio was more positive than that of modern oceans.

Animals↗
PubMedDate not supplied

[T-cell interferon-gamma, tumor necrosis factor-alpha and interleukin-6 receptor binding in patients with multiple sclerosis. Effects of interferon-beta-1b treatment].

INTRODUCTION: Multiple sclerosis (MS) is a T-cell-mediated demyelinating disease of the central nervous system (CNS), in which the cytokine network may be deranged. Interferon (IFN)-gamma, interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha are cytokines with several effects on the neuroimmune system. Specific IFN-gamma, IL-6, and TNF-alpha receptors have been found on human lymphocytes and other cell types. PATIENTS AND METHODS: We assayed IFN-gamma, TNF-alpha, and IL-6 binding on peripheral blood T cells from MS patients, as compared with healthy subjects. T cells from MS patients have significantly less IFN-gamma receptors, and more TNF-alpha and IL-6 receptors than those from controls. Such receptors are of the same type in patients and healthy subjects. By comparing MS patients' subgroups with each other, significant differences in mean Bmax values have been found between patients in a stable phase and those in relapse, and between stable patients and those in an evolutive phase. As far as IL-6 binding is concerned, significant differences in mean Bmax values were observed only between patients in stable phase and those in relapse. RESULTS: T lymphocytes from untreated MS patients, which had significantly smaller amounts of IFN-gamma receptors than those from controls, and more TNF-alpha and IL-6 receptors than controls showed a significant increase in IFN-gamma binding, and a significant decrease in TNF-alpha and IL-6 binding after a 3-month IFN-beta 1b treatment. T-cell IFN-gamma Bmax values were even higher, and those of TNF-alpha and IL-6 were lower after 6 months. CONCLUSION: We discuss these results in terms of MS immunopathophysiology, since activated T cells have decreased IFN-gamma, and increased TNF-alpha and IL-6 receptor amounts.

Adjuvants, Immunologic↗