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Biomedical subjects

F Pallone

Publications and source records attributed to F Pallone.

At least 73 records · Page 4Linked to original sources
PubMed1997

Seroepidemiology of Helicobacter pylori infection and hepatitis A in a rural area: evidence against a common mode of transmission.

BACKGROUND AND AIMS: Recent studies have shown that the age-specific seroprevalence of H pylori infection parallels hepatitis A (HAV), suggesting similar modes of transmission. The aim of this study was to investigate the seroepidemiology of H pylori and HAV in the same setting. PATIENTS: A sample of 705 resident subjects (273 men, age range 1-87 years, median 50) who attended the outpatient medical centre of the rural town of Cirò, Southern Italy (11,000 inhabitants) for blood testing were recruited. METHODS: All subjects completed a structured questionnaire. A serum sample was drawn from each subject and assayed for H pylori IgG by a validated in house enzyme linked immunosorbent assay. Antibodies to HAV were determined in 466 subjects (163 men, age range 1-87 years, median 49). A measure of agreement between H pylori and HAV seropositivity, the kappa statistic, was used. RESULTS: Overall, 446 (63%) subjects were seropositive for H pylori. Of the 466 subjects screened for both H pylori and HAV, 291 (62%) were seropositive for H pylori and 407 (87%) for HAV. Cross-tabulation of these data showed that 275 (59%) were seropositive and 43 (9%) seronegative for both H pylori and HAV, 16 (3%) were seropositive for H pylori, and 132 (28%) were seropositive for HAV (OR = 5.6, CI 3 to 10). There was a parallel, weakly correlated (r = 0.287) rise in the seroprevalence of the two infections with increasing age. However, the agreement between H pylori and HAV seropositivity was little better than chance (kappa = 0.21) and in those aged less than 20 years it was worse than chance (kappa = -0.064). Furthermore, multiple logistic regression analysis did not show any risk factor shared by both infections. CONCLUSIONS: The correlation between H pylori and HAV reflects the age-specific seroprevalence of both infections rather than a true association. This study provides evidence against a common mode of transmission of H pylori and HAV.

Adolescent↗
PubMed1997

Appendectomy is an independent protective factor for ulcerative colitis: results of a multicentre case control study. The Italian Group for the Study of the Colon and Rectum (GISC)

BACKGROUND: Different exogenous factors are believed to play a role in the pathogenesis of ulcerative colitis. Smoking habits and other risk factors have received much attention. It has recently been reported that appendectomy decreases the risk of ulcerative colitis. AIM: Aim of the study was to further examine the role of appendectomy in ulcerative colitis. METHODS: A large multicentre case control study was performed. Cases were all patients with a recent new diagnosis of ulcerative colitis (from 1990 to 1994) at participating centres. One or two controls attending the orthopaedic and surgical units were considered and matched to cases for age (+/- 5 years), sex and year of diagnosis. A total of 536 cases and 755 controls were enrolled. Mean age of cases was 37.9 years (range 2-92). Assessment of exposure was done by examining the clinical records and by interview, if necessary. Smoking habits, alcohol consumption, use of oral contraceptives, type of occupation and area of residence were also recorded. Odds ratio and 95% confidence intervals were calculated by conditional logistic regression analysis. RESULTS: Forty-one out of the 536 cases (7.6%) and 150 out of the 755 controls (19.9%) had been submitted to appendectomy. A total of 110 out of 536 cases (20.5%) and 135 out of 753 (17.9%) controls had had tonsillectomy. Seven out of 41 cases and 15 out of 755 controls underwent appendectomy for recurrent pain. In all ulcerative colitis patients, appendectomy had been performed before the onset of disease. When data were adjusted for the confounding variables, ulcerative colitis patients were less likely to have had appendectomy compared with controls (odds ratio = 0.3, confidence interval = 0.19-0.48). There was no significant association of ulcerative colitis with tonsillectomy (odds ratio = 1.09, confidence interval = 0.76-1.58). The well recognized inverse association of ulcerative colitis with cigarette smoking was also shown in this study. CONCLUSIONS: The present data emerging from a large multicentre study, confirm that appendectomy has a protective role for the development of ulcerative colitis.

Adolescent↗
PubMed1996

Stimulated human lamina propria T cells manifest enhanced Fas-mediated apoptosis.

Lamina propria (LP) T cells respond poorly to a proliferative stimulus delivered via TCR/CD3 pathway, but retain considerable ability to respond to a stimulus delivered via CD2 costimulatory or accessory pathway. In the present study, we showed first that unstimulated LP T cells, as compared to unstimulated peripheral blood (PB) T cells, exhibit an increased level of apoptosis which is further increased following CD2 pathway stimulation, but not following via TCR/CD3 pathway stimulation. We next showed that IL-2 had a sparing effect on apoptosis of unstimulated LP T cells in that IL-2 decreased and anti-IL-2 increased apoptosis of these cells; in contrast, IL-2 had no effect on apoptosis of CD2-pathway stimulated cells. Finally, we showed that increased apoptosis of LP T cells induced by CD2-pathway stimulation is inhibited when Fas antigen is blocked by a nonstimulatory anti-Fas antibody. These studies suggest that LP T cells are characterized by increased susceptibility to Fas-mediated apoptosis most due to a downstream change in the Fas signaling pathway. Given that IFN-gamma secretion is significantly increased in LP T cells in which apoptosis is inhibited, this feature of LP T cells may represent a mechanism of regulating detrimental immune responses in the mucosal environment.

Antibodies↗
PubMed1996

Functional expression of Fas and Fas ligand on human gut lamina propria T lymphocytes. A potential role for the acidic sphingomyelinase pathway in normal immunoregulation.

The expression and function of Fas (CD95/APO-1), a cell surface receptor directly responsible for triggering cell death by apoptosis, was investigated on human T lymphocytes resident within the intestinal lamina propria, a major site of antigen challenge and persistent lymphocyte activation. Three color immunofluorescence and FACS analysis indicated that virtually all freshly isolated human gut lamina propria T lymphocytes (T-LPL) express Fas, together with the marker of progress activation CD45R0. A discrete fraction of freshly isolated T-LPL also constitutively expressed Fas ligand (FasL), perhaps as a result of recent in vivo activation. Importantly, whereas Fas cross-linking did not result in apoptosis induction in peripheral blood T lymphocytes (T-PBL), Fas was found to be fully effective in generating the apoptotic signal in T-LPL. This was associated with the activation of an acidic sphingomyelinase and with ceramide generation, early events known to be involved in Fas-mediated apoptotic signaling. By contrast, acidic sphingomyelinase activation and ceramide production were not detectable in T-PBL after Fas cross-linking. However C2-ceramide, a cell permeant synthetic analog of ceramide, could efficiently induce apoptosis in T-LPL and T-PBL when added exogenously. These data indicate that T-LPL constitutively express both Fas and FasL and that Fas cross-linking generates signals resulting in sphingomyelin hydrolysis and apoptosis, outlining a potential mechanism involved in intestinal tolerance. Moreover, they provide the first evidence of a role for ceramide-mediated pathways in normal immunoregulation.

Apoptosis↗
PubMed1996

Antineutrophil cytoplasmic antibodies are present in long standing type 1 diabetics but do not correlate with selective proteinuria.

Antineutrophil cytoplasmic antibodies (ANCA) are present in systemic vasculitis with or without renal involvement and in inflammatory bowel diseases, conditions which share damage in proteoglycan content of basal membrane. In diabetes, there is a reduction in proteoglycans in the kidney basal membrane, responsible for the decrease in fixed anionic charges and, consequently, for the prevalent anionic proteinuria (albumin, IgG4) even in the early preclinical stage of nephropathy. The aims of this study were to search for the presence of ANCA in long-standing type 1 diabetic patients and to evaluate possible correlations with size- and/or charge-selective proteinuria. Twenty-two type 1 diabetic patients (duration of diabetes 24 years, range 9-30) selected and grouped according to albumin excretion rate values, were studied together with 21 age and sex comparable normal subjects. ANCA, albumin excretion rate, and the clearances of albumin, of prevalently cationic total IgG (IgG) and of anionic IgG4 were evaluated. ANCA were measured using ELISA and indirect immunofluorescence methods; albumin, IgG and IgG4 were tested with RIA or ELISA methods developed in our laboratory. ANCA were found in five patients, three of whom showed proteinuria. 33.3% and 18.2% of patients with normal IgG and albumin clearances respectively had elevated IgG4 clearance. This study shows for the first time the presence of ANCA in long-standing type 1 diabetic patients and confirms a prevalent anionic protein excretion in these patients, but does not show a correlation between the presence of ANCA and proteinuria, even if the presence of ANCA in diseases sharing alterations in proteoglycan content of vascular basal membrane is noteworthy.

Adult↗
PubMed1996

Regulatory cytokines in inflammatory bowel disease.

Several immunological alterations have been described in inflammatory bowel disease, but their role in the pathogenesis of tissue damage of these disorders is not fully known. Activated immune cells produce proinflammatory and regulatory cytokines able to mediate immune mechanisms underlying intestinal inflammation in both ulcerative colitis and Crohn's disease. Although there is no evidence for an aberrant cytokine secretion in the intestinal mucosa of patients with inflammatory bowel disease, observations seem to indicate that locally released cytokines trigger the preferential differentiation of mucosal lymphocytes into TH1 or TH2 subsets. The unresponsiveness of intestinal mononuclear cells to the inhibiting effects of regulatory cytokines may, also, contribute to this differentiation.

Animals↗
PubMed1996

Helicobacter pylori-specific IgG in chronic haemodialysis patients: relationship of hypergastrinaemia to positive serology.

BACKGROUND: Chronic haemodialysis (HD) patients frequently suffer from dyspeptic symptoms and hypergastrinaemia is a common finding in these patients. Helicobacter pylori (H. pylori) infection is associated with dyspepsia and hypergastrinaemia. METHODS: The aim of this study was to determine whether H. pylori is frequently found in HD patients and to explore the relationship of H. pylori with dyspeptic symptoms and/or hypergastrinaemia in these patients. Serum H. pylori specific IgG were measured by an in-house enzyme-linked immunosorbent assay (sensitivity and specificity is 97% and 91% respectively) in 103 chronic HD patients. The patients (53 M, 50 F, mean age f60 +/- 13 years) completed a questionnaire exploring the type, frequency and intensity of dyspeptic symptoms. Fasting plasma gastrin levels were also measured. Serum and plasma samples from 103 hospital patients matched for age, sex and dyspepsia were use as controls. RESULTS: There was no significant difference in terms of serum H. pylori IgG between HD patients and controls (0.977 +/- 0.295 vs 1.046 +/- 0.306 OD respectively). The prevalence of subjects with positive serology was relatively high in both groups, but did not differ between HD patients (73%) and controls (78%). Dyspepsia was reported in 72 (70%) cases. There was no relationship between presence (and grading) of dyspepsia or type of dyspeptic symptoms and H. pylori serology. In the HD group, patients seropositive for H pylori had a significantly higher gastrinaemia than those who were seronegative: 598 +/- 413 ng/ml vs 309 +/- 252 ng/ml (P < 0.0001). The relationship between seropositivity for H. pylori and hypergastrinaemia was significant (P = 0.00038), after adjustment by multiple regression analysis for sex, age, smoking, alcohol, months on dialysis, renal function, drugs, and dyspepsia. CONCLUSIONS: Data of this study suggest that H. pylori may play a role in contributing to hypergastrinaemia of HD patients.

Dyspepsia↗
PubMed1995

Production of immunoglobulin G and G1 antibodies to cytoskeletal protein by lamina propria cells in ulcerative colitis.

BACKGROUND & AIMS: Recent studies suggest an autoantigenic role for tropomyosin-related protein(s) in ulcerative colitis (UC). This study examined whether immunoglobulin G and G1 subclass antibodies against tropomyosins are produced spontaneously by the lamina propria mononuclear cells (LPMCs) that infiltrate the inflamed UC tissue. METHODS: LPMCs were isolated from colonic biopsy specimens from 29 patients with UC, 15 with colonic Crohn's disease (CD), and 13 with non-inflammatory bowel disease (IBD). The autologous peripheral blood mononuclear cells (PBMCs) were obtained. Cells were cultured in vitro and unstimulated for 10 days. Spontaneous production of immunoglobulin G and G1 antibodies against tropomyosins was measured by enzyme-linked immunosorbent assays using highly enriched tropomyosins from skeletal muscle and colonic mucosa. RESULTS: The total immunoglobulin G produced by LPMCs from both patients with UC and CD was comparable but higher than from patients with non-IBD (P < 0.05). However, immunoglobulin G antibodies to tropomyosins were higher in patients with UC than in patients with CD (P < 0.04) and non-IBD (P < 0.02). LPMCs from patients with symptomatic UC produced higher immunoglobulin G antibodies to tropomyosins than patients with UC in remission (P < 0.03), symptomatic CD (P < 0.04), and non-IBD (P < 0.02). Immunoglobulin G antibodies to tropomyosins predominantly belonged to immunoglobulin G1 subclass. The autologous PBMCs showed comparable results. CONCLUSIONS: Immunoglobulin G antibodies predominantly belonging to immunoglobulin G1 subclass and reactive against tropomyosin-related protein(s) are spontaneously produced by LPMCs from the colonic mucosa in patients with UC.

Adolescent↗
PubMed1995

Peripheral monocyte and naive T-cell recruitment and activation in Crohn's disease.

BACKGROUND & AIMS: Transmural perivascular mononuclear cell infiltrates are a feature of Crohn's disease. The aim of this study was a molecular characterization of the mechanisms leading to the formation of these infiltrates. METHODS: Endothelial cell and leukocyte expression of the adhesion molecules directing leukocyte transendothelial migration were studied in situ by immunohistochemical analysis of 10 samples from patients with Crohn's disease and 10 samples from normal controls. Double-staining methods were used to characterize the cells forming the infiltrates. RESULTS: CD11a+ and L-selectin-positive mononuclear cells seemed to be the major component of perivascular infiltrates. The vast majority of these cells were CD68+, CD31+ monocytes/macrophages surrounded by CD3+, L-selectin-positive, CD31+, CD45RA+, and/or CD45RO+ T lymphocytes. T lymphocytes within the vessels expressed both CD45RA and CD45RO markers. Endothelial cells were intercellular adhesion molecule 1 positive and mostly CD34+. Strong adhesion between L-selectin-positive and CD11a+ intravascular mononuclear cells and CD34+ and intercellular adhesion molecule 1-positive endothelial cells were observed. CONCLUSIONS: Data indicate that peripheral mononuclear cells are actively recruited in the submucosa of Crohn's disease tissue; endothelial cells express adhesion molecules highly permissive for transendothelial migration of monocytes and both naive and memory T cells contributing to infiltrates generation; and close membrane contact between migrated macrophages and naive T cells leads to the T-cell transition from naive to memory phenotype within Crohn's disease.

CD3 Complex↗
PubMed1995

Salivary specific IgG is a sensitive indicator of the humoral immune response to Helicobacter pylori.

In humans, salivary antibodies are secreted during humoral immune response. Helicobacter pylori infection is associated with systemic humoral immune response reflected by raised serum levels of specific IgG. The present study was aimed at exploring whether salivary concentrations of specific H. pylori IgG are a reliable indicator of H. pylori infection. Serum and salivary samples were obtained from 291 subjects attending the GI clinic and tested for H. pylori-specific IgG by a direct ELISA (94% sensitivity, 95% specificity for serum determinations) using a crude H. pylori sonicate as antigen. Data are given as optical density (mean +/- S.D.). Levels of salivary H. pylori IgG paralleled those of circulating specific IgG in the 291 subjects studied (0.981 +/- 0.431 vs. 0.777 +/- 0.682, respectively). A significant positive correlation was found between specific H. pylori IgG in sera and saliva samples (r = 0.981, P < 0.0001). An overall concordance between circulating and salivary H. pylori IgG was observed in 238 out of the 291 (81.7%) subjects. Salivary H. pylori IgG represent a sensitive marker of specific humoral immune response and they may substitute circulating H. pylori IgG measurement when sera samples are not available.

Adult↗
PubMed1995

Isotypic analysis of specific antibody response in serum, saliva, gastric and rectal homogenates of Helicobacter pylori-infected patients.

The relationship between systemic and local humoral immune response to Helicobacter pylori is poorly understood. To further address this issue we measured, using ELISA, H. pylori-specific IgG and IgA antibodies in serum, saliva, gastric and rectal homogenates of H. pylori-infected patients. A total of 107 patients who underwent upper GI endoscopy and/or sigmoidoscopy were studied. The isotypic pattern of H. pylori-specific antibodies appeared to differ at the serum, salivary, gastric and rectal mucosa level. Serum H. pylori IgG titers were higher than those of the serum-specific IgA. On the contrary, in saliva samples H. pylori IgA titers were higher than specific IgG titers. In gastric homogenates, specific IgG and IgA titers were similar. H. pylori-specific IgG were detectable in rectal homogenates but no or very low H. pylori-specific IgA were found in the same material. Furthermore, no difference was found in H. pylori IgG and IgA in serum, saliva and gastric homogenates between duodenal ulcer and non-ulcer dyspepsia patients. Data of the present study indicate that, in H. pylori-infected patients, the specific immune response is as follows: (1) it involves the secretory immune system; (2) it is paralleled by the specific salivary IgA; (3) it does not differentiate duodenal ulcer from non-ulcer dyspepsia patients; and (4) it does not take place in the large bowel.

Adult↗
PubMed1995

Transglutaminases in Crohn's disease.

Transglutaminases are a family of Ca-dependent enzymes involved in various biological events. Circulating transglutaminase (factor XIIIa) is decreased in blood of patients with inflammatory bowel diseases. There is evidence that factor XIIIa and tissue type transglutaminase, present in cell cytosol, bind to various proteins of the extracellular matrix. This study examined the value of serum transglutaminase assay in the treatment and follow up of Crohn's disease and then investigated the intestinal location of both forms of transglutaminases by immunohistochemistry in normal and abnormal tissues. Serum transglutaminase activity was assayed in 36 patients with active Crohn's disease (CDAI > 150). Eighteen patients were studied prospectively from relapse into remission. A significant inverse correlation (p < 0.001) was found between circulating transglutaminase and Crohn's disease activity index; a correlation was also found between serum transglutaminase and serum orosomucoid (p < 0.01) and C reactive protein (p < 0.01). Patients were prospectively studied until clinical remission showed improvement in both their CDAI score mean (SD) (230 (46) to 72 (34), p < 0.01) and transglutaminase activity mean (SD) (0.61 (0.12) to 0.93 (0.13) mU/ml, p < 0.01). The immunohistochemistry assessment showed a colocalisation of factor XIIIa and tissue transglutaminase to the extracellular matrix of damaged tissues. In conclusion, these data confirm the value of serum transglutaminase assay as marker of Crohn's disease activity, extend the utility of serum transglutaminase assay to follow up of the disease, and emphasised the role of different types of transglutaminases in extracellular matrix assembly in the damaged tissues.

Adult↗
PubMed1995

Inability of normal human intestinal macrophages to form multinucleated giant cells in response to cytokines.

Multinucleated giant cells are an important feature of the granulomatous reaction in Crohn's disease (CD) but their cellular origin is poorly understood. The aim of this study was to discover if intestinal macrophages are capable of generating multinucleated giant cells in vitro in response to cytokine stimulation. Human intestinal macrophages were isolated from the intestinal mucosa of CD and uninflamed surgical specimens. Isolated macrophages were cultured in chamber slides with and without exposure to a panel of cytokines and cell activators. Cell fusion, multinucleated giant cells formation, and the expression of adhesion molecules were assessed at various time intervals. In contrast with the autologous peripheral monocytes cell fusion was very poor in cultures of control intestinal macrophages and virtually no multinucleated giant cells were seen. Control intestinal macrophages seemed to poorly express the adhesion molecules required for cell to cell adhesion and fusion, namely ICAM-1 and LFA-1. None of these functions was affected by the exposure to cytokines, including interferon gamma. In cultures of macrophages isolated from CD tissues multinucleated giant cell formation spontaneously occurred as early as three days and was not enhanced by the addition of cytokines. CD macrophages seemed to highly express both ICAM-1 and LFA-1. These data show that human intestinal macrophages are unable to form multinucleated giant cells in response to stimuli and support the concept that they are downregulated in a number of functions. The data also suggest that macrophages participating in the ganulomatous reaction in CD are recruited from the circulation.

Cell Culture Techniques↗
PubMed1995

Evidence against an increased risk of Helicobacter pylori infection in dentists: a serological and salivary study.

BACKGROUND: An oral-to-oral route of transmission of Helicobacter pylori infection has been postulated, which is supported by the observation that H. pylori is present in the saliva and in dental plaque. On the basis of this assumption, an increased risk of H. pylori infection among dentists was postulated. METHOD: Serum and salivary H. pylori immunoglobulin (lg)G antibodies were measured in a group of practising dentists. For comparison we also studied a group of controls from the same urban area matched for age, sex, smoking habits, alcohol and non-steroidal anti-inflammatory drug consumption, and history of dyspepsia. RESULTS: There was no significant difference in serum H. pylori lgG antibodies titres between dentists and controls [optical density (OD) 0.991 +/- 0.588 versus 1.025 +/- 0.591, respectively]. Salivary H. pylori lgG were 0.693 +/- 0.726 and 0.661 +/- 0.614 OD in the dentists and control groups, respectively. The frequency of H. pylori-seropositive subjects did not differ between the two groups [22 out of 39 (56%) versus 46 out of 71 (64%)]. A positive saliva assay was found in 23 out of 39 (59%) dentists and in 44 out of 71 (62%) controls. The odds ratio for a dentist being H. pylori-positive was 0.7 (95% confidence interval 0.3-1.7) by serology and 0.9 (95% confidence interval 0.4-2.1) by salivary antibody assay. CONCLUSION: The data of this study do not support the concept that dentists are a high-risk group for H. pylori infection.

Adult↗