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Biomedical subjects

A Focà

Publications and source records attributed to A Focà.

At least 19 recordsLinked to original sources
PubMed2000

Early detection of Leishmania promastigotes in dog bone marrow cultures by acridine orange stain.

An acridine orange staining technique was evaluated in comparison with other well-known methods for the laboratory diagnosis of leishmaniasis. A higher number of promastigotes was found in Novy-MacNeal-Nicolle (NNN) cultures inoculated with canine bone marrow, when culture samples were stained with acridine orange vital stain, compared with those detected using either Giemsa staining or unstained wet mount examination. Based on our data the acridine orange stain is a useful and timely technique in reflecting the true numbers of microorganisms present in a culture and also enhances the visualization of the parasites. The present results warrant further studies with human samples from suspected leishmaniasis patients.

Acridine Orange↗
PubMed2000

Inflammation is associated with carotid atherosclerosis in dialysis patients. Creed Investigators. Cardiovascular Risk Extended Evaluation in Dialysis Patients.

OBJECTIVE: To investigate the relationship between inflammatory processes and atherosclerosis in uraemic patients on chronic dialysis. DESIGN: A cross-sectional study in 138 dialysis patients (92 on haemodialysis and 46 on continuous ambulatory peritoneal dialysis). METHODS: Serum C-reactive protein (CRP), IgG anti-Chlamydia pneumoniae antibodies, lipoprotein (a), fibrinogen and plasma homocysteine as well as the intima-media thickness and the number of atherosclerotic plaques of the carotid arteries (by Echo-Colour-Doppler) were measured in each patient RESULTS: One hundred and eight patients had at least one plaque and 26 had more than six plaques. Serum CRP was above the upper limit of the normal range (5 mg/I) in 85 of 138 patients (62%). IgG anti-Chlamydia pneumoniae antibodies were detectable in 64% of patients (high level in 24%, intermediate in 33% and low in 7%) and undetectable in the remaining 36% of patients. In a multiple regression model age (beta=0.35), serum CRP (beta=0.23), plasma homocysteine (beta=0.19), duration of dialysis (beta=0.19) and pulse pressure (beta=0.18) were independent predictors of intima-media thickness (R=0.54, P < 0.0001). Similarly, age (beta=0.33), serum CRP (beta=0.29), plasma homocysteine (beta=0.20) and serum albumin (beta=-0.18) were independent correlates of the number of atherosclerotic plaques (R = 0.55, P < 0.0001 ). Furthermore, in smokers, the interaction serum CRP-IgG anti-Chlamydia pneumoniae antibodies was the stronger independent predictor (beta=0.43, P=0.0001) of the number of atherosclerotic plaques while no such relationship (P=0.73) was found in non-smokers. CONCLUSIONS: In patients on chronic dialysis treatment CRP is independently associated to carotid atherosclerosis and appears at least in part to be explained by IgG anti-Chlamydia pneumoniae antibodies level. These data lend support to the hypothesis that inflammation plays a role in the pathogenesis of atherosclerosis in these patients.

Adult↗
PubMed2000

Evidence favouring the gastro-oral route in the transmission of Helicobacter pylori infection in children.

OBJECTIVE: Several studies support the view that Helicobacter pylori is acquired in early life and within families. However, the exact route of transmission remains unknown. Given that H. pylori colonizes only the human gastric mucosa, the hypothesis that history of vomiting in siblings may be a relevant risk factor was tested in a paediatric setting. METHODS: One hundred urban children (age range 0.8-16.6 years, median 9), 44% with evidence of active H. pylori infection, were recruited. A structured questionnaire dealing with socio-economic issues was completed. Vomiting siblings and siblings of vomiting index children were screened for H. pylori by means of (13)C-urea breath test. Serum samples from index children were assayed for immunoglobulin G to hepatitis A (HAV) and Epstein-Barr virus (EBV) in order to check for faecal-oral and oral-oral exposure, respectively. RESULTS: Vomiting siblings of H. pylori-infected index children and siblings of H. pylori-infected vomiting index children had a high rate of active H. pylori infection (60 and 67%, respectively). History of vomiting in siblings was positively associated with active H. pylori infection in the index children (multivariate odds ratio 2.4, 95% confidence interval 1.3-4.3). Seropositivity for HAV and EBV was found in 1 and 68 index children, respectively. The agreement between active H. pylori infection and EBV seropositivity was not significant (kappa = 0.26). CONCLUSIONS: History of vomiting in siblings is an independent risk factor for H. pylori. Nowadays, transmission of H. pylori in urban children may involve the gastro-oral route more than the faecal-oral or oral-oral pathways.

Adolescent↗
PubMed1999

Altered cytokine production after human herpes virus type 6 infection.

Several strategies allow viruses to elude the surveillance of the immune system and to establish persistent infection in the host. One of such mechanisms is the immunosuppression caused by the direct infection and functional impairment of immune cells. Human Herpes virus type 6 (HHV-6) is a typical immunosuppressive agent, as suggested by its tropism for both CD4+ and CD8+ T cells, B cells, monocytes/macrophages, megakaryocytes and NK cells. In this study the production of IL-10 and IL-12 by peripheral blood mononuclear cells (PBMC) was evaluated during HHV-6 infection "in vitro". Our results demonstrate that HHV-6 up-regulates IL-10 production by PBMC. Furthermore, our data suggest that rhIFN gamma addition counteracts the effect of HHV-6 in promoting IL-10 release. To gain more insight into the role of IFN gamma, anti-IFN gamma monoclonal antibodies were added to PBMC stimulated with LPS. Neutralization of endogenous IFN gamma upregulated IL-10 release. Furthermore, HHV-6 infection inhibited IFN gamma release induced by LPS in PBMC. No basal production of IL-12 was found in PBMC. Moreover, HHV-6 infection did not induce IL-12 release by PBMC. On the contrary, IL-12 was detected in the supernatants of PBMC treated with LPS with or without rhIFN gamma. In these experimental conditions the further addition of HHV-6 markedly impaired IL-12 production. Moreover, the neutralization of IL-10 resulted in a significant up-regulation of IL-12. Finally our data suggest that the immunodysregulation induced by HHV-6 could be accounted for by a shift from a Th-1 to a Th-2 type cytokine profile.

Cells, Cultured↗
PubMed1998

Hepatitis C virus infection in family setting.

To evaluate risk factors associated with intrafamiliar transmission of hepatitis C virus (HCV), 113 hepatitis C virus index subjects with chronic HCV infection and their 267 family contacts were studied from January 1994 to October 1995. Overall, 16 family contacts (6%) were positive for anti-HCV by ELISA II generation. The prevalence was 11.3% in spouses and 2.9% in other relatives (odds ratios: 4.2; 95% CI: 1.4-12.6). Spouses who had been married to the index cases longer than 20 years had a 7.5-fold risk (95% CI: 1.0-336.3) of HCV seropositivity as compared to those married less than 20 years. In univariate analysis HCV seropositivity was associated with surgical intervention, use of glass syringes and hospitalization. The results of multivariate logistic analysis showed that any parenteral exposure (odds ratios: 3.8; 95% CI: 1.2-12.8) and sexual contact with an anti-HCV index case (odds ratios: 3.0; 95% CI: 1.0-9.4) were both independent predictors of HCV seropositivity among household contacts of HCV positive index cases. These findings indicate that sexual contact and any parenteral exposure both play an independent role in the spread of HCV infection in the family setting.

Adolescent↗
PubMed1998

Suggestion against an oral-oral route of transmission for Helicobacter pylori infection: a seroepidemiological study in a rural area.

In this study the seroepidemiology of H. pylori and Epstein-Barr virus was compared in the same setting. A sample of 705 subjects completed a structured questionnaire. A serum sample was drawn from each subject and assayed for H. pylori IgG. Antibodies to Epstein-Barr virus were determined in a subgroup of 466 subjects. Cross-tabulation of data showed that 274 (58.8%) subjects were seropositive and 20 (4.3%) were seronegative for both infections, 17 (3.6%) were seropositive for H. pylori, and 155 (33.3%) were seropositive for Epstein-Barr virus (odds ratio=2.08, 95% confidence interval: 1.008-4.3). Nevertheless, the agreement between H. pylori and Epstein-Barr virus seropositivity was no better than chance (kappa=0.067) and the age-related seroprevalence curve of Epstein-Barr virus was similar in H. pylori seropositive and seronegative subjects. Furthermore, multiple logistic regression analysis did not show any risk factor shared by both infections. The findings of this study do not support the hypothesis that H. pylori and Epstein-Barr virus share a common mode of transmission. It can be speculated that the oral cavity may not be an important reservoir for H. pylori.

Adult↗
PubMed1998

Kinetics of IL-8, MIP-1 alpha, TNF alpha, IL-1 beta, IL-1ra and IL-10 in human whole blood samples triggered by smooth and rough LPS.

An in vitro model for the study of sepsis mediators was used to investigate the effects of two different lipopolysaccharides (LPS), a smooth (LPS-S) and a rough (LPS-R) type, on the release of chemokines (IL-8 and MIP-1 alpha) and cytokines (TNF alpha, IL-1 beta, IL-1ra and IL-10) from human whole blood samples. TNF alpha level increased significantly vs. control, at 4 h and 8 h after the challenge with smooth and rough type of LPS respectively. Concentrations of the two chemokines studied, IL-8 and MIP-1 alpha, were significantly elevated following stimulation by both LPS, and reached concentrations significantly different from controls at 4, 8 and 24 h. After 24 h of incubation both LPS produced a significant IL-10 increase, although such change was more substantial with the rough type. Present data suggest an early and maintained release of chemokines regardless of the type of LPS used and often in absence of a significant increase in primary pro-inflammatory cytokines.

Chemokine CCL4↗
PubMed1997

Prevalence, risk factors, and genotype distribution of hepatitis C virus infection in the general population: a community-based survey in southern Italy.

In 1996 the prevalence, risk factors, and genotype distribution of hepatitis C virus (HCV) infection were assessed in the general population of a town in southern Italy. The sample was selected from the census by a systematic 1:4 sampling procedure. The participation rate was 96.6%. Among the 1,352 subjects enrolled, 195 (14.4%) tested reactive to antibody to HCV (anti-HCV) with enzyme immunoassay (EIA 3). When further tested with recombinant immunoblot assay (RIBA 3), 170 subjects (87.2%) tested positive, 23 subjects (11.8%) had indeterminate results, and 2 subjects (1%) tested negative. Thus, the overall anti-HCV EIA-positive RIBA-confirmed prevalence was 12.6% (170 of 1,352 subjects) and increased from 1.3% in subjects younger than 30 years to 33.1% in those > or =60 years of age. This latter age group accounted for 72.3% of all anti-HCV-positive subjects. Females tested positive more frequently than males (14.1% vs. 10.5%; P < .05). Alanine transaminase (ALT) concentrations were abnormal in only 4.1% (7/170) of anti-HCV EIA-positive RIBA-confirmed subjects. This suggests that ALT screening is not useful in the detection of anti-HCV-positive subjects in a general population. The results of multiple logistic regression analysis showed that an age of less than 45 years, the use of glass syringes, and dental therapy were all independent predictors of anti-HCV positivity. HCV RNA was detected by polymerase chain reaction in 75.9% of the 195 anti-HCV EIA-positive subjects: in 84.7% (144/170) of the RIBA-confirmed subjects; in 17.4% (4/23) tested as RIBA indeterminate; and in neither of the two subjects who tested RIBA negative. HCV type 1b was detected in 75 subjects (50.7%), type 2b in 1 subject (0.7%), type 2c in 66 subjects (44.6%), type 3a in 4 subjects (2.7%), and type 4 in two subjects (1.3%). These figures differ from those of Italian patients with chronic liver disease in whom genotype 2 is more rare. None of the individuals was infected with more than one genotype. The distribution of the two most common HCV viral types (1b and 2c) was not statistically different in terms of mean age, sex, or risk factors and suggests that they may have had a parallel spread in this community. These findings provide one of the highest overall anti-HCV prevalence rates in a general population with a likely cohort effect, i.e., decreased risk of infection along generations. These observations may indicate an epidemic or focus of hepatitis C that occurred several years earlier. The majority of anti-HCV-positive subjects in the oldest age group and with no clinical evidence suggests that HCV infection is a very prolonged and indolent disease.

Adolescent↗
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

Productive HHV-6 infection in differentiated U937 cells: role of TNF alpha in regulation of HHV-6.

This study characterizes the effect of differentiation on the resistance of the human monocytic cell line U937 to human herpes virus type 6 (HHV-6). The use of monocytic cell line has the advantage of avoiding genetic variations among different donors. The HHV-6 infection was compared in undifferentiated U937 cells and U937 cells differentiated with a combination of vitamin D3 and retinoic acid. Undifferentiated U937 cells were highly resistant to HHV-6 infection. Differentiation of U937 cells was accompanied by an increase in permissiveness for HHV-6 demonstrated in terms of extracellular virus production and viral antigen positive immunofluorescent cells. Tumor necrosis factor alpha (TNF alpha) appears to be an essential mediator during the first line defences of the host against viruses, even though its role during viral infection remains controversial. For this reason we examined the behaviour of TNF alpha in differentiated U937 upon HHV-6 infection. No basal production of TNF alpha was found in culture supernatants, while HHV-6 infection up-regulated TNF alpha release. The addition of human recombinant-TNF alpha to HHV-6 infected cells induced a marked cytotoxic effect accompanied by an increased release of extracellular virus, whereas it did not affect viral replication, as shown by the unmodified percentage of antigen positive cells. In conclusion, TNF alpha acts as a soluble mediator of cytotoxicity against HHV-6 infected U937 cells, but it fails to induce an antiviral state.

Antibodies, Blocking↗
PubMed1997

A population based survey of hepatitis B virus infection in a southern Italian town.

BACKGROUND: The level of endemicity and modes of transmission of hepatitis B virus infection may change over time. AIMS: To assess prevalence of and risk factors for hepatitis B infection in the general population. SUBJECTS: A total of 1352 subjects residing in a Southern Italian town in the year 1996. METHODS: Subjects were selected from the census by a systematic 1:4 random sampling procedure. Hepatitis B surface antigen and antibodies to hepatitis B core antigen were detected by ELISA. The association (Odds Ratio) linking hepatitis B seropositivity to potential risk factors was estimated by univariate and multivariate analysis. RESULTS: The participation rate was 96.6%. The overall prevalence of hepatitis B surface antigen and antibodies to hepatitis B core antigen were 0.8% and 21.5%, respectively. Hepatitis B surface antigen prevalence was 0.2% in subjects younger than 30 years, peaked to 2.5% in the age-group 40-49 years, and decreased to 0.3% in those 60 years and older. Antibodies to hepatitis B core antigen positivity linearly increased from 6.2% in subjects < 30 years of age to 37.1% in those 60 years or older (p < 0.01). The results of multiple logistic regression analysis showed that age > 45 years (Odds Ratio = 1.9; Confidence Intervals 95% = 1.2-3.0), use of glass syringes (Odds Ratio = 2.2; Confidence Intervals 95% = 1.5-3.4), surgical intervention (Odds Ratios = 1.8; Confidence Intervals: 95% = 1.3-2.6), and positivity for antibodies to hepatitis C virus infection (Odds Ratios = 2.6; Confidence Intervals 95% = 1.5-4.3) were all independent predictors of the likelihood of hepatitis B positivity. CONCLUSIONS: Given that a significant proportion of the general population undergoes surgical intervention, the association found between hepatitis B positivity and this exposure highlights the importance of further developing efficient procedures for the sterilization of instruments as well as the use of disposable materials to control the spread of infection.

Adult↗
PubMed1996

Impairment of immunological functions in genetically epilepsy-prone rats.

1. In genetically epilepsy-prone rats (GEPR-9s), which represent a natural genetic model of epilepsy, we observed that the number of peritoneal macrophages was significantly lower with respect to normal rats, and that some functional parameters (i.e. phagocytosis and intracellular killing) of these macrophages were impaired. 2. The count of lymphocyte populations showed a predominance of T-helper over T-cytotoxic/suppressor both in the spleen and lymph nodes. Moreover, an increased T-cell/B-cell ratio was observed in GEPR-9s. Flow cytometry revealed that GEPR-9s spleens possessed a large percentage of T-helper cells in comparison to normal rats. 3. By using concanavalin A-induced proliferation of GEPR-9s cultured lymphocytes, we have shown increased functional activation. 4. We suggest that the alterations in T-cell functions in GEPR-9s could be due to the involvement of the neuroendocrine system in the modulation of immunity, in the shift between Th1 and Th2, and in the activation of stress response.

Animals↗
PubMed1996

Effect of RO 23-9424, cefotaxime and fleroxacin on functions of human polymorphonuclear cells and cytokine production by human monocytes.

The way in which an antibiotic interacts with host defences could influence the clinical outcome of many infectious diseases. The impact of RO 23-9424, a novel dual-action and extended-spectrum antibiotic, was studied on several functions of human polymorphonuclear neutrophils (PMNs). A significant (P < 0.05) increase of the superoxide (O2-) released by phorbol-myristate acetate (PMA) -stimulated PMN (10-100 mg/L) can be observed in the RO 23-9424 pre-treated cells. RO 23-9424, particularly at low dosages, showed an interesting but not statistically significant effect on PMN phagocytosis. Higher dosages of RO 23-9424 (50-200 mg/L) and fleroxacin (20-200 mg/L) significantly reduced PMN chemotaxis. Cytokine production by human monocytes were also evaluated after incubation with the antibiotic (100-200 mg/L) in both basal conditions and in response to endotoxin (lipopolysaccharide, LPS). In the LPS-treated cells, RO 23-9424 (100 mg/L) significantly (P < 0.05) enhanced the tumour necrosis factor-alpha (TNF-alpha) levels, compared with LPS controls after 4 h of incubation. RO 23-9424 (200 mg/L) was able to reduce in a dose-dependent way LPS-induced interleukin-1 beta (IL-1 beta) after 4 and 24 h of incubation. Interleukin-8 (IL-8) release was not significantly changed by RO 23-9424. Cefotaxime (200 mg/L) significantly (P < 0.05) increased the basal levels of IL-1 beta and reduced basal IL-8 concentration after 24 h of incubation. The lower concentration of cefotaxime reduced the LPS-stimulated IL-8 levels. Fleroxacin (100 mg/L) enhanced basal levels of IL-8. The potentiated PMN phagocytosis, the significantly enhanced O2- release by PMA-stimulated PMN and the dimetric changes of TNF-alpha and IL-1 beta appeared peculiar for RO 23-9424 and may have useful therapeutical implications.

Anti-Infective Agents↗
PubMed1995

In vitro effects of novel glycopeptide antibiotics on the reactivity of the lipopolysaccharide (LPS) of S. minnesota R595.

Four novel glycopeptide antibiotics, namely MDL 62708, MDL 63155, MDL 62827, MDL 62873 (mideplanin), plus teicoplanin, which differ in their chemical structure, were used to examine the relationship between the structure of glycopeptides and their LPS neutralization activity. Compound MDL 62708 (100 micrograms/ml) significantly reduced (P < 0.01 vs. antibiotic-free LPS, by Fisher's PLSD Test) metachromatic reactivity of S. minnesota R595 LPS (500 micrograms/ml) as evaluated by the DMB test. The remaining glycopeptides showed a significant reduction of the metachromatic reactivity, although at concentrations (333 and 1000 micrograms/ml) higher than MDL 62708. Data obtained with LAL test appeared in accordance with those of the other techniques: all the glycopeptides used (100 and 1000 micrograms/ml) significantly (P < 0.05) reduced the reactivity of S. minnesota R595 LPS (50 pg/ml), and the lowest concentration of MDL 62708 (10 pg/ml) used produced a substantial, although not significant, reduction of the LPS reactivity with LAL. The antibiotic/LPS ratios associated to a significant reduction of LPS reactivity were 3.3/5 (wt/wt) and 2/1 (wt/wt) for DMB and LAL tests respectively. Such ratio appeared to be even lower for MDL 62708. In conclusion, the four new glycopeptides, when tested at an antibiotic/LPS ratio about 1000 times lower than that which can be found in vivo, were able to reduce the reactivity of LPS in the in vitro models used. Teicoplanin aglycone MDL 62708, which also lacks the teicoplanin fatty acid, seems to have the same anti-LPS activity as the parental antibiotic, thus suggesting an important role for the glycopeptide backbone and NH2 groups in LPS-neutralizing effect.

Analysis of Variance↗
PubMed1993

Inhibition of endotoxin-induced interleukin 8 release by teicoplanin in human whole blood.

Antibiotic-induced endotoxin (lipopolysaccharide; LPS) release may precipitate septic shock. In the present study the effect of teicoplanin, which has been reported to neutralize LPS in experimental models, on LPS neutralization was investigated in human whole blood samples. Levels of interleukin 8, a preinflammatory cytokine which was stimulated by Salmonella minnesota R595 LPS (12.6 micrograms/ml), were monitored over time. Interleukin 8 concentrations increased over time up to 24 h. When LPS was preincubated with teicoplanin (antibiotic: LPS ratio 20:1, w/w), interleukin 8 concentrations were found significantly (p < 0.05) reduced at 4, 8 and 24 h after LPS challenge. Interleukin 1 beta (at 4, 8 and 24 h) and tumor necrosis factor alpha (at 8 and 24 h) levels were also significantly decreased by teicoplanin. In this experiment model, a teicoplanin:LPS ratio 100-fold less than the ratio achievable in plasma of septic shock patients was able to reduce interleukin 8, which has been correlated with the severity of septic disease.

Humans↗
PubMed1992

Teicoplanin reduces in-vitro reactivity and murine lethality of Salmonella minnesota R595 lipopolysaccharide.

Three different tests were performed to investigate the effect of teicoplanin on lipopolysaccharide (LPS). After incubation for 3 h with teicoplanin, LPS from Salmonella minnesota R595 showed reduced reactivity in the metachromatic dimethyl-methylene blue assay and the limulus amoebocyte lysate test. In addition, galactosamine-sensitized mice had an increased survival rate, from 29% to 72%, when teicoplanin was pre-incubated for 3 h with the LPS to be injected intraperitoneally. The results suggest that teicoplanin may have a neutralizing effect on LPS.

Animals↗