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Biomedical subjects

A Velardi

Publications and source records attributed to A Velardi.

At least 55 records · Page 3Linked to original sources
PubMed1992

Gallbladder volume in adults, and relationship to age, sex, body mass index, and gallstones: a sonographic population study.

The influence of gender, age, body size, cholelithiasis, and obesity on fasting gallbladder volume (GBV) was investigated by real-time ultrasonography in a general population cohort of subjects whose ages were between 30 and 69 yr, living in Bari, a Southeastern Italian city. Of the 2076 subjects analyzed, 1246 (60%) were males and 830 (40%) were females (mean age 50 yr). Among them, 1703 subjects were healthy, 108 had gallstones, and 265 were obese. Fasting GBV in healthy individuals was larger in males (M) than in females (F) [M, 18.7 +/- 0.3 (SEM) ml vs. F, 17.0 +/- 0.3 ml; p less than 0.001] and obese (M, 23.4 +/- 1.5 ml vs. 19.7 +/- 0.9 ml; p less than 0.05). The trend was similar in gallstone patients, but it was not statistically significant (M, 23.0 +/- 2.0 ml vs. F, 18.8 +/- 1.5 ml; t = 1.64). Gallbladder size correlated positively with body size in the lean healthy population (p less than 0.01), increased with age in healthy nonobese males (p less than 0.01), and was smaller in healthy males than in males with gallstones (0.01 less than p less than 0.02) and obese, in both sexes (p less than 0.01). We conclude that fasting GBV 1) is larger in lean healthy and obese males than females, 2) increases with age in lean males and with body size in healthy lean females, and 3) is greater in patients with gallstones and in obese subjects, and this might partially account for the defective gallbladder motor function reported in these patients.

Adult↗
PubMed1991

Interleukin-6 is constitutively produced by human CTL clones and is required to maintain their cytolytic function.

Maturation of cytolytic T lymphocytes from nonlytic precursors requires cytokines in addition to IL2. Interleukin-6 is the principal cytokine that cooperates with IL2 in the induction of CTL differentiation from murine and human thymocyte precursors. However, a cytotoxic differentiation factor (CDF) role of IL6 for mature T cells is challenged by data indicating that IL2 alone is sufficient for CTL generation. The aim of this study was to identify a model system in which IL6 acted as a CDF for human peripheral T cells. We noted that IL6 was endogenously produced by CTL clones in the course of their expansion with APC, lectin, and IL2. The majority of several hundred T-cell clones, both CD4+ and CD8+, produced IL6 in response to relatively high doses of IL2. Other experiments that compared the cytolytic function of CTL clones cultured in the presence of IL6 with that of the same clones cultured in the absence of IL6 demonstrated that IL6 contributes to the cytolytic ability of the majority of human CTL clones. Our data suggest that IL6 acts in an autocrine fashion to support CTL differentiation in human T-cell clones.

CD4 Antigens↗
PubMed1991

Analysis of T cells bearing different isotypic forms of the gamma/delta T cell receptor in patients with systemic autoimmune diseases.

The expression of gamma/delta T cell receptor (TCR) on peripheral blood CD3+ cells circulating in 74 patients with different systemic autoimmune diseases was evaluated. There was a significant increase in the gamma/delta T cell number only in patients with primary Sjögren's syndrome (SS) and in untreated patients with systemic lupus erythematosus (SLE). Unlike healthy subjects, a subgroup of patients with SLE and SS displayed a marked increase in gamma/delta T cells. Immunosuppressive treatment of patients with active SLE led to a normalization of the gamma/delta T cell number. Analysis of surface phenotype showed that when patient gamma/delta T cells were expanded in the peripheral blood, they were not activated but bore "memory" markers. In addition, they preferentially expressed the disulfide linked form of the TCR, except in progressive systemic sclerosis where the nondisulfide form was displayed. Serial determinations in single patients demonstrated that the gamma/delta T cell increase is a persistent immunological feature in these patient subgroups.

Adolescent↗
PubMed1990

Cytolytic function of clonable T cells after human bone marrow transplantation.

We evaluated T-cell mediated lymphokine activated killer (LAK) function during the late (greater than 5 months) reconstitution phase after T cell-depleted allogeneic bone marrow transplantation (BMT) for hematologic malignancy. Since LAK cells are sustained by interleukin-2 (IL-2), we also investigated the ability of post-BMT T cells to produce IL-2. These functions were investigated at the clonal level. More than 200 T-cell clones from six long-term BMT recipients were generated and compared with 60 T-cell clones derived from two normal controls. Almost all the CD8+ clonal cultures from BMT recipients expressed cytolytic activity in a lectin-dependent cellular cytoxicity assay. Interestingly, a higher proportion of BMT recipient-derived cytolytic clones were able to mediate LAK activity in comparison with control clones (28% versus 4%, P less than .05). However, T-cell clones from BMT recipients, as opposed to control clones, were largely incapable of producing IL-2. Given the high proportions of post-BMT circulating CD8+ T cells, it appears that, in long-term BMT recipients, the precursors of nonspecific LAK effectors are present at above normal levels. However, their function may be defective in vivo due to poor IL-2 production.

Bone Marrow Transplantation↗
PubMed1990

Antibacterial polysaccharide antibody deficiency after allogeneic bone marrow transplantation.

Allogeneic bone marrow-engrafted adults immunized with meningococcal types A and C and pneumococcal type 14 polysaccharide antigens showed only low antibody titers of the IgM class, no antibody titers of the IgG or IgA classes, and no bactericidal activity in vitro. The analytical isoelectrofocusing showed the appearance of a restricted pattern of clonotypes in a minority of subjects. These observations are consistent with the hypothesis that B cells in bone marrow transplant patients express some characteristics of neonatal B cells and suggest that polysaccharide-protein conjugates, rather than isolated polysaccharide, might be utilized in the setting of bone marrow transplantation.

Adult↗
PubMed1990

Isolation and functional characterization of rat pancreatic acini.

The Authors describe an optimized procedure for the isolation of rat pancreatic acini and the preliminary results concerning the functional characterization of the cells. Isolation is carried out by two sequential digestive steps in a KREBS modified medium containing collagenase, separated by an intermediate step in which acini separation is fostered by incubation in a Ca++ free medium containing the Ca++ chelator EDTA. Final separation is obtained through the application of mechanical forces by aspirating the suspension in plastic pipettes. The choice of the collagenase, the duration and the entity of the mechanical dissociation strength are the main modifications to the classic procedure and allow to obtain a very high yield of cells maintaining their ability to secrete enzymes for a long period (6-7 hours). Functional characterization is completed mainly by the determination of the amylase release stimulated by increasing doses of cholecystokinin.

Amylases↗
PubMed1990

Fluorimetric study of intracellular Ca++ homeostasis in isolated rat pancreatic acini.

A fluorimetric method for the study of intracellular Ca++ metabolism in rat pancreatic acini is described. Following previous reports on the utilization of the new intracellularly trapped fluorescent dye fura2 in human lymphocytes, the authors point out the relevance of the cellular and fura2 concentration as critical issues for an accurate evaluation of Ca++ homeostasis. A dose-response curve to both carbamoylcholine and cholecystokinin is reported, demonstrating the ability of the cells to respond to hormonal stimulation with a transient Ca++ peak. The almost complete absence of noise in the recorded traces allow to carry out an evaluation of the intracellular mechanism related to Ca++ mobilization with a very high sensitivity.

Animals↗
PubMed1989

T-cell response to anti-CD2 monoclonal antibodies in Down's syndrome.

Peripheral blood mononuclear cells from 10 subjects with cytogenetically documented Down's syndrome (DS) and from 10 age- and sex-matched healthy controls were assayed for their ability to proliferate in response to phytohaemagglutinin, anti-CD3 (OKT3), or anti-CD2 (T11(2) plus T11(3] monoclonal antibodies. Interleukin 2 (IL-2) receptor expression and IL-2 production in mitogen-pulsed lymphocyte cultures was also investigated in parallel. DS cells responded poorly to all the blastogenic stimuli used in this study. Under certain experimental conditions (anti-CD3 or anti-CD2 antibody stimulation), the patients' lymphocytes expressed low levels of IL-2 surface receptors and failed to produce normal amounts of this lymphokine. Studies are currently in progress in our laboratories to determine whether these defects are due to an impairment of the early signalling events surrounding the complexing of CD3, CD2, or lectin receptors to their respective ligands.

Adolescent↗
PubMed1989

Lymphokine production by T-cell clones after human bone marrow transplantation.

T cells recovering after bone marrow transplantation (BMT) were analyzed for their phenotypic and functional features by two-color immunofluorescence and a high efficiency cloning technique. A predominance of cells co-expressing natural killer (NK)-related surface antigens, such as Leu 7 (CD57) and CD11b, was detected within both the CD4+ and CD8+ subsets from 5 months postgrafting onward. Such cells are virtually absent among normal circulating CD4+ cells and account for a minority (approximately 30%) of normal CD8+ cells. Postgrafting T cells representative of the whole range of NK-related antigen co-expression were selected from six patients for clonal analyses. In control subjects, 63% and 41% of the CD4+ and CD8+ clones, respectively, produced interleukin-2 (IL-2) whereas approximately 30% of either CD4+ or CD8+ control clones produced interferon (IFN)-gamma. At variance, and irrespective of their CD4+/CD8+ phenotype, lower proportions of BMT recipient-derived clones produced IL-2 (20% and 12%, respectively), whereas the majority of both CD4+ and CD8+ clones (75% and 71%, respectively) released high amounts of IFN-gamma. Purified populations of CD57+/CD11b+ v negative cells from two BMT recipients and two control subjects were cloned and subsequently evaluated for IL-2 and IFN-gamma production. CD57+/CD11b+ cell-derived clones were poor IL-2 producers in both normal subjects and BMT patients. In contrast, IL-2-producing clones were frequent (62% to 79%) among those derived from CD57-/CD11b- cells from normal subjects, whereas they were still represented at lower than normal proportions, ie, 25% to 41%, among clones generated from BMT recipients. CD57+/CD11b+ cells gave rise to comparably high proportions of IFN-gamma producing clones in both normal subjects and BMT recipients (approximately 80%). In contrast, IFN-gamma producing clones were approximately 25% to 50% of CD57-/CD11b- cell-derived clones in both normal subjects and BMT patients. Therefore, while the predominance of NK-related antigen-positive T cells may be predictive of poor IL-2 and high IFN-gamma production, the immune derangement in long-term BMT recipients is further enhanced by the finding that all T cells may be poor IL-2 producers. It is also suggested that IL-2 production is a preferential function of T cells that do not express CD57 and CD11b, whereas IFN-gamma production is attributable to T cells that express CD57 and CD11b.

Antigens, CD↗
PubMed1989

Gallstone prevalence and gallbladder volume in children and adolescents: an epidemiological ultrasonographic survey and relationship to body mass index.

To assess the prevalence of gallstone disease and the behavior of gallbladder (GB) volume in childhood and adolescence, an ultrasonographic survey was carried out on 1570 subjects (age range 6-19 yr). Entered in the study were 750 males and 752 females (attendance rate, 95.7%). Gallstones were detected in two females aged 13 and 18 yr, respectively. None of the subjects in the study population had undergone cholecystectomy. The overall prevalence of gallstone disease was equal to 0.13% (0.27% in the female sex). A positive family history for biliary calculous disease was present in one of the two lithiasic girls. A progressive increase of GB volume with age was observed in both sexes, and figures were greater in males, than in age-matched females. A positive and statistically significant relationship was found between GB volume and body mass index (BMI) in both sexes. Obesity was recognized in 188 males (25.3%) and 167 females (25.0%). Obese subjects exhibited larger GB volumes than the nonobese age- and sex-matched controls. The study supports the view of a very low prevalence of gallstone disease in people younger than 20. It also provides information on GB size in relation to age, sex, and BMI.

Adolescent↗
PubMed1988

Acquisition of Ig isotype diversity after bone marrow transplantation in adults. A recapitulation of normal B cell ontogeny.

To gain insight into the prolonged susceptibility to infections noted after allogeneic bone marrow transplantation (BMT), multiple parameters of the humoral immune system were serially monitored in ten bone marrow recipients. IgM B cells appeared in the circulation 2 to 4 mo after engraftment. During the first 6 mo, the IgM B cells expressed low levels of CD21 (C3d/EBV receptors) and were largely CD38+. IgG and IgA B cells were also found to coexpress surface IgM and IgD, indicating that they may be involved in a process of isotype switch. These features are characteristic of neonatal B cells. To explore the pattern of Ig isotype switch, the emergence of plasma cell precursors for each of the four IgG subclasses was examined by culturing blood lymphocytes with PWM or LPS and enumerating bone marrow plasma cells. A marked IgG2 and IgG4 plasma cell deficiency and a relative increase in IgG1 and IgG3 plasma cells were detected both in vitro and in vivo. Serum IgG2 and IgG4 levels were deficient for more than 18 mo after BMT, elevated IgG1 levels accounting for the normal or increased levels of total IgG. The data suggest that a selective unresponsiveness to polysaccharide Ag and IgG2 subclass deficiency may contribute to the late bacterial infections in BMT recipients. These features of gradual development of the humoral immune system in adults undergoing successful marrow engraftment reproduce some of the maturational steps that occur during normal B cell ontogeny over the first 1 to 2 yr of life.

Adolescent↗
PubMed1988

Increased number of CD4 cells able to bind to natural killer cell targets in the peripheral blood of AIDS related complex patients.

CD4 cells forming conjugates with natural killer target cells (K562 cells) were measured in the peripheral blood of anti-HIV antibody positive AIDS related complex (ARC) patients and in three control groups (asymptomatic individuals at risk, normal healthy people and patients with acute hepatitis B). These CD4 cells, which are unable to kill K562 cells, were significantly increased in ARC patients as compared to the control groups. Our data indicate that classical CD4 cells are partially replaced, in ARC patients, by a population of natural killer-target binding granular CD4 lymphocytes, and suggest that the functional abnormalities of helper T cells in these patients may be in part a consequence of the relative predominance of these non IL-2 and BCGF producing cells within the circulating CD4 population.

AIDS-Related Complex↗
PubMed1988

Imbalances within the peripheral blood T-helper (CD4+) and T-suppressor (CD8+) cell populations in the reconstitution phase after human bone marrow transplantation.

Peripheral blood T cell subsets were evaluated in 11 patients during the reconstitution phase after allogeneic bone marrow transplantation and compared with 11 age-matched controls. The proportion of cells coexpressing Leu7 and CD11b (C3bi receptor) markers was determined within the CD4+ (T-helper) and the CD8+ (T-suppressor) subsets by two-color immunofluorescence analysis. CD4+ and CD8+ T cells reached normal or near-normal values within the first year posttransplant. In contrast to normal controls, however, most of the cells in both subsets coexpressed the Leu7 and CD11b markers. T cells with such phenotype display the morphological features of granular lymphocytes (GLs) and a functional inability to produce interleukin 2 (IL 2). These T cell imbalances were not related to graft v host disease (GvHD) or to clinically detectable virus infections and may account for some defects of cellular and humoral immunity that occur after bone marrow transplantation.

Adolescent↗