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Biomedical subjects

F Dazzi

Publications and source records attributed to F Dazzi.

At least 55 records · Page 3Linked to original sources
PubMed1995

CD25-negative hairy cell leukaemia: intracytoplasmic detection of Tac antigen and interferon-induced surface expression.

Hairy cell leukaemia (HCL) is a chronic lymphoproliferative disease of B-cell lineage. One of the peculiar immunophenotypic markers is the strong expression of the p55 chain of the interleukin-2 receptor (IL2R), recognized by anti-CD25 (or anti-Tac) monoclonal antibody. However, it is known that in rare cases CD25 may not be detectable, even when variant forms of HCL are excluded. The possibility has not been investigated that in these situations CD25 is present in the cytoplasm of the neoplastic cells. This paper describes a case in which the clinical, histological, and electron microscopic features were consistent with a typical HCL. Immunophenotype analysis showed the whole spectrum of markers of HCL, except for the expression of IL2R. The soluble form of the molecule was, however, increased in the patient's serum. Cytospin staining of the neoplastic B cells with anti-CD25 clearly demonstrated the presence of IL2R in the cytoplasm of hairy cells. When the cells were cultivated in vitro in the presence of interferon-alpha 2b, CD25 was detectable at the membrane level. These findings suggest that at least some cases of CD25-negative HCL may express cytoplasmic IL2R.

Aged↗
PubMed1995

Failure of B cells of chronic lymphocytic leukemia in presenting soluble and alloantigens.

B-cell-type chronic lymphocytic leukemia (B-CLL) patients have immunological abnormalities of both B and T lymphocytes. Since T cell defects might depend upon a defective accessory function of neoplastic B lymphocytes, we analyzed the ability of peripheral blood B cells of seven B-CLL patients to stimulate allogenic normal T cells in mixed lymphocyte reaction (MLR) and to present tetanus toxoid (TT) to autologous T cells. In both systems, neoplastic B lymphocytes show a defective antigen-presenting function, which is more evident with disease progression. Such a defect cannot be ascribed to a decreased MHC class II molecule expression nor to an abnormal IL-1 beta production, but it can be partially accounted for by a low B7 expression. Pretreatment of neoplastic B cells with interleukin-4 (IL-4) restores primary MLR, but has little effect on the response to TT. The effect of IL-4 is not mediated by quantitative modifications of class II and B7 molecule expression or of IL-1 beta production.

Antigen Presentation↗
PubMed1995

A role for platelet-derived growth factor in drug-induced chronic ergotism? A case report.

Generalized vasoconstriction in chronic ergot poisoning is attributed both to the ergotamine activity on alpha-adrenergic receptors and to its direct action on vascular smooth muscle cells. The authors propose that endothelial wall, chronically damaged by ergot alkaloids, releases platelet-derived growth factor (PDGF), which contributes to vasoconstriction and promotes further arterial obstruction. Their hypothesis is supported by the increased PDGF activity found in plasma of a patient suffering from chronic ergotism.

Chronic Disease↗
PubMed1994

Biased TCR gene usage in alloreactive T cells specific for a structurally dissimilar MHC alloantigen.

Two models of allorecognition of MHC molecules have been proposed. One emphasizes specificity for MHC molecule-bound peptides and the other for exposed MHC polymorphisms. We predicted that the latter model would predominate in responder:stimulator combinations whose MHC molecules differed extensively in their TCR-contacting surfaces and that this would be reflected in biased TCR usage. Two panels of anti-DR11 T cell clones were generated, one from a DR17 and the other from a DR15 responder. The TCR-contacting surfaces of DR17 and DR11 have multiple differences, and those of DR15 and DR11 are very similar. TCR analysis by polymerase chain reaction amplification and mAb staining revealed that five out of nine DR17 anti-DR11 clones used the V beta 13 and two the V beta 6, family. In contrast seven different V beta families were used by the eight DR15 anti-DR11 clones. A similar bias in TCR V beta usage was observed in the polyclonal DR17 and DR11 T cell lines from which the clones were derived, and in a second DR17 anti-DR11 line from a different individual. These results support the concept that specificity for the foreign MHC structure itself may play an important role in the alloresponse between responders and stimulators with structurally dissimilar MHC molecules.

Amino Acid Sequence↗
PubMed1988

Natural killer cell function and lymphoid subpopulations in acute non-lymphoblastic leukaemia in complete remission.

A long term follow-up study has been undertaken in 33 patients with acute non-lymphoblastic leukaemia (ANLL) in order to establish whether a correlation exists between the clinical course and the immunologic pattern of lymphoid subpopulations. Peripheral blood lymphoid cells have been investigated longitudinally (each 1 to 4 months) during complete remission (CR), by morphologic, phenotypic and functional analyses. Particular attention has been paid to the evaluation of the natural killer (NK) cell compartment, by the detection of cells expressing an NK-related phenotype and by NK in vitro assay. Among the patients so far evaluable, 20 relapsed (R) and 10 are long survivors in CR 'off therapy' (LS). The most relevant finding was represented by statistically higher values of NK activity observed in LS vs. R patients (P less than 0.01). The removal of adherent cells before the NK assay, performed to investigate the possible inhibitory effect on NK function played by the macrophage component, abolished this difference, due to a selective increase of NK function in the R group. The longitudinal study revealed that NK activity tended to decrease in individual patients who subsequently relapsed. These data suggest a possible role of NK cells in the relapse control of ANLL, although it cannot be excluded that the low level of NK activity observed in the R group is the result of impending relapse rather than its cause.

Adolescent↗
PubMed1987

Immunologic abnormalities in angioimmunoblastic lymphadenopathy.

In this study we describe the results of phenotypic, serologic, and functional analyses performed in nine patients with angioimmunoblastic lymphadenopathy (AILD). The study investigates the nature of the T-cell defects which seem to represent a consistent feature in this disease. The study, based on the analysis of T-cell subsets with monoclonal antibodies and on functional in vitro tests, showed the following main abnormalities: reduction of the absolute number of circulating T-cells; inversion of the CD4/CD8 ratio, both in the peripheral blood and in the involved lymph nodes; high percentages of activated T-cells (CD8+/HLA-DR+); defective T-cell response in vitro to the PHA mitogen; and minimal helper and enhanced in vitro suppressor functions. Some of these immunologic dysfunctions are also observed in acquired immune deficiency syndrome (AIDS) which has in common with AILD several clinical features. However, no evidence of HTLV-III infection could be demonstrated in our patients with AILD.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Rearrangement for the T-cell receptor gene and co-expression of immature T-cell markers and natural killer cell phenotype, in a patient with acute lymphoblastic leukaemia.

We describe a patient with acute lymphoblastic leukaemia whose blasts co-expressed immature T-cell markers and nearly the entire phenotypic repertoire of NK cells. The T-cell nature of the proliferating blasts was proven by the demonstration of the rearrangement for the beta-chain of the T-cell antigen receptor. Although an abnormal phenotypic expression related to the neoplastic proliferation cannot be formally excluded, it is possible that the cells in this patient may represent the clonal expansion of a normal subpopulation of T-cell lineage NK-related cells frozen at an early stage of differentiation. These features provide arguments for discussing the controversial issue of the ontogeny of NK cells and their relationship to the T-cell lineage.

Acute Disease↗
PubMed1983

Role of accessory cells in the induction of a secondary cytotoxic response to Moloney murine sarcoma virus-induced tumors.

The role of Ia-positive accessory cells in the generation of a secondary cytotoxic response to tumor-associated antigens induced by Moloney murine sarcoma virus (M-MSV) was evaluated. Spleen cells from M-MSV-immune A.TL mice, depleted of accessory cells by anti-Iak serum plus C treatment and stimulated in secondary mixed leukocyte tumor cell culture (MLTC) with syngeneic Ia-negative A6ATL Moloney leukemic cells, failed to generate virus-specific cytotoxic T lymphocytes (CTL). CTL generation in Ia-depleted MLTC may be reconstituted by the addition of nonimmune Ia-positive spleen or peritoneal cells obtained not only from syngeneic A.TL but also from I-incompatible A.TH mice. This lack of restriction observed in accessory cell function is explained in terms of a nonspecific mechanism of CTL triggering mediated by soluble factors. In fact, IL 2 as well as supernatants obtained from I region-incompatible cultures consisting of M-MSV-immune, Ia-depleted A.TL spleen cells and A.TH Ia-positive cells, reconstituted secondary virus-specific CTL generation.

Animals↗
PubMed1982

High-performance liquid chromatography for the quantitative determination of the urinary metabolites of toluene, xylene, and styrene.

A new high-pressure liquid chromatography (HPLC) method for simultaneous quantitative determination of the urinary metabolites of toluene, m-xylene, and styrene (hippuric acid, m-methylhippuric acid, phenylglyoxylic acid, mandelic acid) is described. The extraction procedure was performed on acidified urines, after addition of 4-hydroxybenzoic acid as internal standard, using a butylchloride/isopropanol mixture and drying 0.5 ml of the organic layer under nitrogen flow. The residue obtained was dissolved in 0.1 ml water/acetonitrile and 5 microliters were injected into an HPLC apparatus equipped with a 0.26 X 25 cm HC ODS SIL X column. Absorbance measures were performed at 225 nm throughout the investigation. All metabolites were clearly separated in a short time (12 min) and the amounts of other urinary compounds affecting the analysis were so small that the measurement of low concentrations of the urinary metabolites could be easily performed. Linear calibration curves were obtained from 0.1 to 3 mg/ml and a correlation coefficient greater than 0.99 was found between concentrations of the standards and areas of the peaks. Statistical analysis confirms that this method, which has a high reproducibility, is simple, reliable, and useful for the biologic monitoring of industrial exposure to aromatic compounds.

Chromatography, High Pressure Liquid↗
PubMed1981

[Glycosylated hemoglobin in chronic renal insufficiency].

Glycosylated haemoglobin (Hb A1) was measured by ion-exchange column chromatography in 70 normal subjects, 40 diabetics and 83 patients with chronic renal failure, including 54 on chronic dialysis. The results, compared with glycemic balance and renal function, suggest that the coexisting occurrence of any kind of chronic renal failure can really interfere with the blood level of the fast haemoglobin fractions, disclosing new interesting perspectives of diagnostic and clinic employment.

Blood Glucose↗