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C Vitale

Publications and source records attributed to C Vitale.

At least 37 records · Page 2Linked to original sources
PubMed2000

Synthesis of new aromatic (C17-C20)-locked side-chain analogues of calcitriol (1alpha,25-dihydroxyvitamin D(3)).

The synthesis of four new analogues of calcitriol (1alpha, 25-(OH)(2)-D(3)) possessing aromatic and conjugated double bond units at the side chain are described. The triene system is introduced using the Lythgoe-Hoffmann La Roche convergent Wittig-Horner approach. The key steps in the preparation of the requisite upper fragments are the introduction of the side chain with the E-conjugated aromatic system and its photochemical conversion to the Z counterpart.

Animals↗
PubMed2000

Expression of HLA class I-specific inhibitory receptors in human cytolytic T lymphocytes: a regulated mechanism that controls T-cell activation and function.

Different families of major histocompatibility complex (MHC)-specific inhibitory receptors (NKRs) play a major role in natural killer (NK) cell function, allowing discrimination between normal cells and cells that do not express adequate amounts of MHC class I antigens. This occurs in most instances as a consequence of viral infection or tumor transformation. In T lymphocytes, expression of NKR is mostly confined to activated CD8+ cytolytic T lymphocytes (CTLs). While NKR expression by CTLs may be viewed as a mechanism preventing damages to normal cells by those CTLs that have acquired NK-like activity, it may also down regulate TCR-mediated T cell activation, thus, impairing CTL functions. The finding that certain cytokines can modulate killer inhibitory receptor expression in CTLs is of major interest and might be instrumental in novel therapeutic approaches aimed at the down regulation ofT-cell function in transplantation or autoimmunity.

Cytokines↗
PubMed2000

Phenotypic and functional analysis of the HLA-class I-specific inhibitory receptors of natural killer cells isolated from peripheral blood of patients undergoing bone marrow transplantation from matched unrelated donors.

INTRODUCTION: Limited information is available on the natural killer cell reconstitution after bone marrow transplantation and on the possible role of these cells in graft-versus-host-disease. MATERIALS AND METHODS: Blood samples were collected at different time intervals after transplantation. Lymphocytes were analyzed for informative markers by immunocytofluorimetric analysis. Natural killer cells derived from patients undergoing matched unrelated donor transplant were cloned by limiting dilution in the presence of phytohemoagglutinin and IL2. The natural killer cell clones were analyzed for cytolytic activity. RESULTS: In the nine patients analyzed undergoing transplantation from sibling donors, the majority of peripheral blood lymphocytes during the first 80 d after BMT were represented by T lymphocytes, while in the 15 patients undergoing matched unrelated donor transplant natural killer cells consistently outnumbered T lymphocytes. During the early phases after transplantation, most CD56+CD3- natural killer cells did not express CD16 which was expressed at later intervals. Analysis of the inhibitory receptors specific for HLA-class I molecules showed that CD94/NKG2A, specific for HLA-E, unlike normal donors, was expressed by all natural killer cells including the early appearing CD16-negative ones. Killer inhibitory receptors of the Ig superfamily were expressed late and in low percentages after transplantation and were always coexpressed with CD94/NKG2A. Natural killer-cell clones efficiently lysed the HLA-class I-negative cell lines K562 and 721-221. Natural killer-cell populations or clones isolated from patients with graft-versus-host-disease, failed to lyse donor or recipient derived phytohemoagglutinin-induced lymphoblasts. CONCLUSION: Our analysis shows that (1) recipients of matched unrelated donors transplants exhibit a high proportion of NK cells (2) all NK cells express CD94/NKG2A while the HLA-class I-specific inhibitory receptors of Ig superfamily appear at later stages and (3) donor NK cells do not lysed donor or recipient target cells.

Adolescent↗
PubMed1999

Engagement of p75/AIRM1 or CD33 inhibits the proliferation of normal or leukemic myeloid cells.

P75/AIRM1 is a recently identified surface molecule that belongs to the sialoadhesin family and displays homology with the myeloid cell antigen CD33. In lymphoid cells, p75/AIRM1 is confined to natural killer cells and mediates inhibition of their cytolytic activity. In this study, we show that p75/AIRM1 is also expressed by cells of the myelomonocytic cell lineage, in which it appears at a later stage as compared with CD33. In vitro proliferation and differentiation of cord blood-derived CD34(+) cells (induced by stem cell factor and granulocyte-macrophage colony-stimulating factor) were consistently inhibited by the addition of anti-p75/AIRM1 mAb. Engagement of CD33 led to inhibition in some experiments. A sharp decrease of cell proliferation/survival was detected in all three p75/AIRM1+ chronic myeloid leukemias analyzed when cultured in the presence of either anti-p75/AIRM1 or anti-CD33 mAbs. Thus, the present study suggests that p75/AIRM1 and CD33 may play a regulatory role in normal myelopoiesis and may be viewed as suitable target molecules to counteract the proliferation/survival of chronic myeloid leukemias.

Antibodies, Monoclonal↗
PubMed1999

Inhibitory receptors sensing HLA-G1 molecules in pregnancy: decidua-associated natural killer cells express LIR-1 and CD94/NKG2A and acquire p49, an HLA-G1-specific receptor.

Trophoblastic cells lack classical HLA class I and class II molecules but express HLA-G1. Although this may prevent allorecognition by maternal T cells, it renders trophoblastic cells potentially susceptible to lysis by natural killer (NK) cells. As shown here, only a fraction of peripheral-blood NK cells in pregnant women express the HLA-G1-specific CD94/NKG2A and/or LIR-1 receptors. However, all NK cells isolated from maternal decidua during the first trimester expressed either one or both of these receptors. Perhaps more importantly, a fraction of cells expressed p49, an HLA-G1-specific inhibitory receptor, undetectable in peripheral-blood NK cells. p49 was expressed on virtually all NK cells isolated from placenta at term. Functional analyses revealed that the HLA class I-negative 221 lymphoblastoid cell line transfected with HLA-G1 was only partially protected from lysis by peripheral-blood NK cells isolated from pregnant women, whereas it was fully protected from decidual NK cells. As indicated by the addition of specific antibodies to cytolytic tests, all the above receptors contributed to HLA-G1 recognition by decidual NK cells, although p49 would appear to play a predominant role.

Animals↗
PubMed1999

Transforming growth factor-beta-induced expression of CD94/NKG2A inhibitory receptors in human T lymphocytes.

Different HLA class I-specific killer inhibitory receptors (KIR) are expressed in vivo by a fraction of activated T cells, predominantly CD8+, in which they may inhibit TCR-mediated cell functions. In an attempt to identify mechanisms leading to KIR expression in T cells, we analyzed the effect of transforming growth factor-beta (TGF-beta) in T cells responding to bacterial superantigens in vitro. We show that TGF-beta induces the expression of CD94/NKG2A in cells responding to toxic shock syndrome toxin 1 or to other staphylococcal superantigens. Remarkably, maximal CD94 expression occurred at (low) TGF-beta concentrations which have no substantial effect on lymphocyte proliferation. Maximal CD94 expression occurred when TGF-beta was added shortly after the cells were placed in culture. No expression could be induced in CD94/NKG2A-negative T cell clones. Although both CD4+ and CD8+ expressed CD94, the simultaneous expression of NKG2A was mostly confined to CD8+ cells. Monoclonal antibody-mediated cross-linking of CD94/NKG2A led to an impairment of T cell triggering via CD3, as determined in a redirected killing assay using the Fcgamma receptor-positive P815 murine target cells.

Animals↗
PubMed1999

Idiopathic calcium nephrolithiasis.

Calcium nephrolithiasis (CaNL) accounts for more than 70% of all renal stones, and its prevalence has increased in the last decades. Under this definition are included patients passing stones, composed of calcium oxalates and/or calcium phosphates. Current views of the pathogenesis of CaNL are based on the role of metabolic abnormalities which concur to render urines more conducive to crystallization. Therefore, the diagnostic approach is aimed at detecting these abnormalities, and the medical treatment assumes that a decrease in the risk of lithogenesis will result in remission or improvement of recurrences. The workup of the patients with CaNL begins with the analysis of passed stones and X-ray, sonography or other imaging techniques. Eligible patients, that is, both recurrent active stone formers and single-stone formers with individual risk factors, are considered for a metabolic evaluation, by which a number of blood and urine parameters are measured and others calculated. These include estimates of urine state of saturation with calcium and uric acid salts, net gastrointestinal alkali absorption, renal threshold of phosphate and other renal clearances and net acid and total nitrogen excretions. Basically, this screening is informative on renal function, metabolic abnormalities and their pathophysiology, risk of stone formation and dietary habits. During treatment it gives information about patient compliance and adverse effects of therapy. The cost of a comprehensive screening in Piedmont is 192,000 ITL (100 Euro) and rises to 300,000 ITL (154 Euro) if hormones and hydroxyproline are measured. In individual patients second- and third-level studies are performed, in order to detect systemic diseases which account for about 20% of CaNL in our series. Cost-to-benefit analysis has shown that the medical procedures for CaNL yield considerable saving in terms of difference between expenditure for drugs and testing and reduction of stone events. However, the current workup cannot be considered exhaustive, because misleading events may hamper the relation between laboratory findings and clinical outcome, and factors other than urine composition have appeared on the scenario of nephrolithiasis. These represent our challenge for the third millennium.

Adult↗
PubMed1999

[Clinical and metabolic features of renal calculi in adults in regard to age of onset].

BACKGROUND: In this paper, the clinical and metabolic patterns of nephrolithiasis in different ages of adulthood are studied. METHODS: Eight-hundred patients observed at the Mauriziano Hospital between 1990 and 1995, were classified into 3 groups, on the basis of age at the onset of disease: A: 20 through 39 years; B: 40 through 59; C: 60 years and over. RESULTS: Calcium-oxalate stones had a lower recurrence in C (19.1%) and B (31.5%) than in A (41.7%). Pure uric acid stones recurred in 18.9% of C, 16.7% of B and 4.3% of A. The prevalence of hypercalciuria was higher in A (50.3%) than in B (35.9%) and C (36%); so did hypocitraturia. Hyperuricuria was lower in A (5%, p < 0.05) than in B (9.4%) and C (10%). Low urine pH (< 5.5) was 13% in A, 21.3% in B, 38% in C. Prevalence of hyperoxaluria was about 14% in all groups. The whole prevalence of secondary forms of stone disease was 13% in A, 12% in B and 30% in C. Differences among groups were mainly due to prevalence of urological abnormalities and urinary tract infection. In patients without metabolic disturbances. urological abnormalities or urinary tract infections altogether, were 4.6% in A; 5.2% in B; 33% in C. Urological approach removed 8% of stones in A, 5.6% in B and 10.2% in C. CONCLUSIONS: Higher morbidity in younger patients could be due to a lower prevalence of easier-passing uric acid stones. The higher occurrence of urological disturbances and struvite stones in the elderly could explain the higher morbidity in this group.

Adult↗
PubMed1998

HLA class I-specific inhibitory receptors in human T lymphocytes: interleukin 15-induced expression of CD94/NKG2A in superantigen- or alloantigen-activated CD8+ T cells.

A fraction of human T lymphocytes, predominantly CD8+, express receptors for HLA class I molecules typical of natural killer cells (natural killer receptors or NKRs) that inhibit T cell receptor-mediated functions. Herein, we analyzed possible mechanism(s) leading to the expression of NKRs by T cells responding to superantigens or allogeneic cells in vitro. We show that, in the presence of interleukin 15 (IL-15), T cells (depleted of NKR+ cells) responding to toxic shock syndrome toxin 1 de novo express CD94, a molecule that is part of a heterodimeric NKR with a broad specificity for different HLA class I alleles. Maximal CD94 expression occurred when IL-15 was added shortly after the cells were placed into culture, and CD94 expression started 4-6 days after addition of IL-15. Although both CD4+ and CD8+ cells expressed CD94, the simultaneous expression of NKG2A (i.e., the other component of the CD94/NKG2A inhibitory NKR) was confined to CD8+ cells. Similar data were obtained in T cell populations activated in mixed lymphocyte cultures in the presence of IL-15. The expression of CD94/NKG2A led to an impairment of allo-specific cytolytic activity by mixed lymphocyte culture-derived T cell populations or clones. Remarkably, cytolysis could be restored by the addition of anti-CD94 mAb, i.e., by masking the inhibitory NKRs.

Antigens, CD↗
PubMed1998

Cytokine-induced expression of killer inhibitory receptors in human T lymphocytes.

Killer inhibitory receptors (KIRs) represent a new family of HLA-class I-specific receptors. KIRs are involved in the function of Natural Killer cells and allow these cells to discriminate between normal cells and cells with impaired expression of HLA-class I molecules. KIRs are also expressed by a subset of cytolytic T lymphocytes in which they may exert an inhibitory effect on TCR-mediated function. Here we review recent data indicating that cytokines such as IL-15, may induce the de novo expression of CD94/NKG2A (a KIR which operationally detects the expression of various HLA-class I alleles). The expression of CD94/NKG2A has been documented not only in CD34+ precursors undergoing maturation towards NK cells, but also in mature T cells which respond in vitro to superantigens or allogeneic cells.

Animals↗
PubMed1997

Interleukin-15-induced maturation of human natural killer cells from early thymic precursors: selective expression of CD94/NKG2-A as the only HLA class I-specific inhibitory receptor.

Immature postnatal thymocytes were shown to contain precursors which, under suitable culture conditions, give rise to phenotypically and functionally mature natural killer (NK) cells. Here, we analyzed the effect of different cytokines for their ability to induce the expression of HLA class I-specific inhibitory receptor(s) during the process of NK cell development from immature thymocytes. From thymocyte cell suspensions depleted of CD2+, CD3+, CD4+, CD8+, CD56+, and CD16+ cells, we further removed cells expressing HLA class I-specific inhibitory receptors including CD94/NKG2-A, p58.1, and p58.2 by immunomagnetic bead separation. The resulting cells did not contain any of the above NK receptors as determined by immunofluorescence and flow cytometric analysis, as well as by reverse transcriptase polymerase chain reaction (RT-PCR) amplification using appropriate sets of primers. Although different cytokines have been used, including interleukin (IL)-7, stem cell factor (SCF), IL-2, and IL-15, only IL-2 or IL-15 induced cell proliferation when used alone. Moreover, maturation towards CD3- CD56+ cells displaying cytolytic activity against the HLA class I- targets K562 or 221 was detectable in cultures containing IL-15 used alone or in combination with IL-7 or SCF. On the other hand, these CD3- CD56+ cell populations did not lyse HLA class I+ target cells, including autologous PHA blasts. Analysis of the expression of the various HLA class I-specific inhibitory NK receptors revealed the presence of high proportions of CD94/ NKG2-A+ cells, while the NK receptors belonging to the Ig superfamily were undetectable both by immunofluorescence and by RT-PCR analysis. The expression of CD94/NKG2-A appeared to be responsible for the inability of cells to lyse HLA class I+ target cells. Thus, addition of anti-CD94 monoclonal antibodies of IgM isotype resulted in lysis of autologous target cells. The use of 221 cells transfected with different HLA class I alleles as target cells confirmed the broad class I specificity of CD94/NKG2-A receptor. Our experiments indicate that IL-15 provides an appropriate stimulus to the expression of CD94/NKG2-A, but not of other class I-specific NK receptors in the process of maturation of NK cells from thymocyte precursors.

Alleles↗
PubMed1997

Inhibitory receptors for HLA class I molecules on cytolytic T lymphocytes. Functional relevance and implications for anti-tumor immune responses.

In recent years, the molecular mechanism by which natural killer cells lyze, or fail to lyze, different target cells has been elucidated. Natural killer cells express receptors which recognize MHC class I molecules on target cells. This interaction leads to inhibition of cytolytic activity, thus preventing lysis of target cells. The receptors belong to two distinct molecular types: (1) the lg superfamily which includes receptors (p58.1, p58.2, p70, and p140) which recognize specific HLA allotypes; (2) CD94 molecules which display a broad specificity for HLA class I molecules. Recently, a subset of cytolytic T lymphocytes has been shown to express the various natural killer cell receptors. Such T cells are detectable in peripheral blood, spleen, tonsils, and lymph nodes, but not in the thymus and cord blood. In some instances, two or more natural killer receptors can be coexpressed at the single cell level. Surface marker analysis has revealed that natural killer cell receptor-positive T cells always express a memory phenotype. Moreover, they are characterized by a skewed T cell receptor V beta repertoire. Further analysis of the T cell receptor VDI sequences revealed that natural killer cell receptor-positive, CD3-positive cells isolated from a given individual are oligoclonal or monoclonal in nature. Crosslinking of natural killer receptors leads to inhibition of different T cell functions, including non-specific lysis of appropriate HLA class I-negative target cells, T cell receptor mediated cytotoxicity, and cytokine production. The inhibitory effect on T cell receptor-mediated function has important implications. Thus, the expression of natural killer cell receptors as a consequence of chronic antigen stimulation may result in functional impairment of specific cytolytic T lymphocytes. Preliminary data indicate that this phenomenon may occur in tumor or virally infected patients. Remarkably, various patients with large granular lymphocyte expansions characterized by a CD3/ natural killer receptor-positive phenotype had chronic viral infections. The fact that antigen-specific cytolytic T lymphocytes may simultaneously express T cell and natural killer cell receptors, both recognizing HLA class I molecules but mediating opposite signals, offers new perspectives in our appreciation of the regulation of T cell responses and offers new clues for understanding the immunopathological events involved in certain diseases.

Antigens, Neoplasm↗
PubMed1997

HLA-class I-specific inhibitory receptors in human cytolytic T lymphocytes: molecular characterization, distribution in lymphoid tissues and co-expression by individual T cells.

A subset of cytolytic T lymphocytes has been shown to express receptors of the NK type (NKR) which can inhibit T cell cytotoxicity induced via the TCR-CD3 pathway. In this study, by the analysis of full length cDNA amplified from representative T cell clones, we show that NKR belonging either to the lg superfamily, including p58.1, p58.2, p70 and p140, or to the C-type lectin superfamily (CD94/NKG2A), display sequences which are identical to those of the corresponding NKR expressed by CD3-NK cells. Moreover, a fragment of cDNA encoding the NKG2A protein was consistently amplified from all CD94+ T cell clones analyzed. Since different NKR types can be expressed by T cells, we analyzed whether individual T cells could co-express more than one NKR. Analysis of either resting or activated (and cultured) T cell populations revealed that two or more NKR can be co-expressed by single T cells. Moreover, by the analysis of T cell clones, we show that co-expressed receptors are functional and can inhibit independently the TCR-induced cytolytic function. Finally, we investigated whether NKR+ T lymphocytes were also present in lymphoid tissues. No such cells were found in thymus or cord blood, thus further supporting the notion that they represent memory T cells. On the other hand, they were present in all the peripheral tissues analyzed including spleen, lymph nodes and tonsils.

Animals↗
PubMed1997

Clinical and biochemical patterns of presentation in monolateral and bilateral calcium nephrolithiasis.

To investigate patterns of monolateral and bilateral nephrolithiasis, we enrolled 196 patients with idiopathic calcium stone disease (ICaSD) and 36 with proven primary hyperparathyroidism (PHP). Monolateral disease occurred in 45 subjects with ICaSD and 3 with PHP. All had had three or more stone events. They were studied for a number of clinical and biochemical parameters. The expected prevalence of monolateral stone disease was calculated according to the binomial distribution of random events. Whereas the observed and expected prevalence of monolateral nephrolithiasis did not differ in PHP, the distribution did not follow a chance pattern in ICaSD, since monolateral disease was still frequent among patient with more than 6 episodes. To find out whether monolateral and bilateral ICaSD had distinct pathogenic mechanisms the two groups were compared for clinical and biochemical patterns: no differences emerged concerning metabolic derangements, urine saturation and diet-related biochemistries. Bilateral stone-formers had a higher recurrence rate, but a similar number of stone-operations or ESWL. In 81 of 151 bilateral idiopathic stone-formers in which we were able to assess the exact number of stone events in left and right kidney, the distribution of stones between kidneys did not differ from the binomial distribution. In conclusion, while PHP-associated nephrolithiasis presents predictable patterns, ICaSD comprises a subset in which the disease occurs monolaterally. These forms cannot be distinguished from bilateral forms with common clinical features or routine biochemistries.

Age of Onset↗
PubMed1997

Expression of HLA class I-specific inhibitory receptors by chronically activated cytolytic T lymphocytes: useful or harmful to the host?

T cells, primarily chronically activated cytolytic T lymphocytes (CTL), can express human leukocyte antigen class I-specific inhibitory receptors previously identified in natural killer cells. Engagement of these receptors leads to inhibition of CTL function. Although the receptor expression may represent a safety device to prevent autoimmunity, it may result in the inability to control viral spread or tumour growth, i.e. two main functions of CTLs. The physiopathologic implications of this event are discussed.

Animals↗
PubMed1996

Human CD8+ T lymphocyte subsets that express HLA class I-specific inhibitory receptors represent oligoclonally or monoclonally expanded cell populations.

A small percentage of human T lymphocytes, predominantly CD8+ T cells, express receptors for HLA class 1 molecules of natural killer type (NK-R) that are inhibitory for T-cell antigen receptor (TCR)-mediated functions. In the present study, it is demonstrated that the various NK-R molecules typically expressed by NK cells are also expressed on periheral blood T lymphocytes. These CD3+ NK-R+ cells have a cell surface phenotype typical of memory cells as indicated by the expression of CD45RO and CD29 and by the lack of CD28 and CD45RA. Furthermore, by the combined use of anti-TCR V beta-specific antibodies and a semiquantitative polymerase chain reaction assay, the TCR repertoire in this CD3+ NK-R+ cell subset was found to be skewed; in fact, one or two V beta families were largely represented, and most of the other V beta s were barely detected. In addition, analysis of recombinant clones of the largely represented V beta families demonstrated that these V beta s were oligoclonally or monoclonally expanded.

CD3 Complex↗
PubMed1996

Effects of mineral composition of drinking water on risk for stone formation and bone metabolism in idiopathic calcium nephrolithiasis.

1. To assess whether the mineral content of drinking water influences both risk of stone formation and bone metabolism in idiopathic calcium nephrolithiasis, 21 patients were switched from their usual home diets to a 10 mmol calcium, low-oxalate, protein-controlled diet, supplemented with 21 of three different types of mineral water. Drinking water added 1, 6 and 20 mmol of calcium and 0.5, 10 and 50 mmol of bicarbonate respectively to the controlled diet. 2. The three controlled study periods lasted 1 month each and were separated by a 20 day washout interval. Blood and urine chemistries, including intact parathyroid hormone, calcitriol and two markers of bone resorption, were performed at the end of each study period. The stone-forming risk was assessed by calculating urine saturation with calcium oxalate (beta CaOx), calcium phosphate (beta bsh) and uric acid (beta UA). 3. The addition of any mineral water produced the expected increase in urine output and was associated with similar decreases in beta CaOx and beta UA, whereas beta bsh varied marginally. These equal decreases in beta CaOx, however, resulted from peculiar changes in calcium, oxalate and citrate excretion during each study period. The increase in overall calcium intake due to different drinking water induced modest increases in calcium excretion, whereas oxalate excretion tended to decrease. The changes in oxalate excretion during any one study period compared with another were significantly related to those in calcium intake. Citrate excretion was significantly higher with the high-calcium, alkaline water. 4. Parathyroid hormone, calcitriol and markers of bone resorption increased when patients were changed from the high-calcium, alkaline to the low-calcium drinking water. 5. We suggest that overall calcium intake may be tailored by supplying calcium in drinking water. Adverse effects on bone turnover with low-calcium diets can be prevented by giving high-calcium, alkaline drinking water, and the stone-forming risk can be decreased as effectively as with low-calcium drinking water.

Adult↗