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Vittorio Sambri

Publications and source records attributed to Vittorio Sambri.

At least 19 recordsLinked to original sources
PubMed2006

Chlamydia pneumoniae replicates in Kupffer cells in mouse model of liver infection.

AIM: To develop an animal model of liver infection with Chlamydia pneumoniae (C. pneumoniae) in intraperitoneally infected mice for studying the presence of chlamydiae in Kupffer cells and hepatocytes. METHODS: A total of 80 BALB/c mice were inoculated intraperitoneally with C. pneumoniae and sacrificed at various time points after infection. Chlamydiae were looked for in liver homogenates as well as in Kupffer cells and hepatocytes separated by liver perfusion with collagenase. C. pneumoniae was detected by both isolation in LLC-MK2 cells and fluorescence in situ hybridization (FISH). The releasing of TNFA-alpha by C. pneumoniae in vitro stimulated Kupffer cells was studied by enzyme-linked immunosorbent assay. RESULTS: C. pneumoniae isolation from liver homogenates reached a plateau on d 7 after infection when 6 of 10 animals were positive, then decreased, and became negative by d 20. C. pneumoniae isolation from separated Kupffer cells reached a plateau on d 7 when 5 of 10 animals were positive, and became negative by d 20. The detection of C. pneumoniae in separated Kupffer cells by FISH, confirmed the results obtained by culture. Isolated hepatocytes were always negative. Stimulation of Kupffer cells by alive C. pneumoniae elicited high TNF-alpha levels. CONCLUSION: A productive infection by C. pneumoniae may take place in Kupffer cells and C. pneumoniae induces a local pro-inflammatory activity. C. pneumoniae is therefore, able to act as antigenic stimulus when localized in the liver. One could speculate that C. pneumoniae infection, involving cells of the innate immunity such as Kupffer cells, could also trigger pathological immune reactions involving the liver, as observed in human patients with primary biliary cirrhosis.

Animals↗
PubMed2006

Production of reactive oxygen species and expression of inducible nitric oxide synthase in rat isolated Kupffer cells stimulated by Leptospira interrogans and Borrelia burgdorferi.

AIM: To evaluate the production of reactive oxygen species (ROS) and the expression of inducible nitric oxide synthase (iNOS) in rat isolated Kupffer cells (KCs) stimulated by Leptospira interrogans and Borrelia burgdorferi. METHODS: Rat Kupffer cells were separated by perfusion of the liver with 0.05% collagenase, and purified by Percoll gradients. Purified Kupffer cells were tested in vitro with alive L. interogans and B. burgdorferi preparations. The production of ROS was determined by chemiluminescence, whereas iNOS protein expression was evaluated by Western blot assay using anti-iNOS antibodies. RESULTS: B. burgdorferi and to a less extent L. interrogans induced ROS production with a peak 35 min after infection. The chemiluminescence signal progressively diminished and was undetectable by 180 min of incubation. Leptospirae and borreliae induced an increased iNOS expression in Kupffer cells that peaked at 6 hours and was still evident 22 h after infection. CONCLUSION: Both genera of spirochetes induced ROS and iNOS production in rat Kupffer cells. Since the cause of liver damage both in leptospiral as well as in borrelial infections are still unknown, we suggest that leptospira and borrelia damage of the liver can be initially mediated by oxygen radicals, and is then maintained at least in part by nitric oxide.

Animals↗
PubMed2006

Systemic fungemia and hepatic localizations of Fusarium solani in a liver transplanted patient: an emerging fungal agent.

The incidence of invasive fungal infection is increasing especially in the field of transplantation, affecting as many as 50% of bone marrow transplant (BMT) patients with neutropenia and 5-20% of solid-organ transplant (SOT) recipients. Fusarium species are soil saprophytes and plant pathogens. They may cause superficial mycoses or important opportunistic infections in patients with bone marrow suppression and neutropenia, they have been rarely described in solid organ recipients, and up to now there have been no reports of such infection in isolated liver transplanted patients. We describe a case of disseminated Fusarium solani infection with hepatic localization in a liver transplanted patient that resolved with the administration of amphotericin B. Our observation confirms that Fusarium spp. are emerging pathogens that may most frequently affect not only BMT patients and patients with hematological malignancies, but also SOT patients. They may cause both localized and disseminated infection. In conclusion, Fusarium spp. etiology should be considered in the context of infectious diseases following liver transplantation.

Adult↗
PubMed2006

A decrease in the immunoglobulin G antibody response against the VlsE protein of Borrelia burgdorferi sensu lato correlates with the resolution of clinical signs in antibiotic-treated patients with early Lyme disease.

The purpose of this study was to evaluate the diagnostic performance of the LIAISON Borrelia Screen (Diasorin, Saluggia, Italy), a new automated immunoassay based on the chemiluminescent technology (chemiluminescence immunoassay). To assess whether a decrease in a negative value in the anti-VlsE immunoglobulin G (IgG) antibody titer was correlated with a positive response to treatment, a group of serially collected serum samples from 67 patients with culture-confirmed erythema migrans was retrospectively studied. All the patients had been treated with antibiotics and were free of disease within 3 to 6 months of follow-up. All the 15 patients who were found to be IgG positive at the time of enrollment and who were bled at least four times during the follow-up became IgG seronegative at 2 to 6 months posttreatment. These results indicate that a decline in the anti-VlsE antibody titer coincides with effective antimicrobial therapy in patients with early localized Lyme disease.

Adult↗
PubMed2005

Identification of new potential vaccine candidates against Chlamydia pneumoniae by multiple screenings.

Chlamydia are intracellular bacteria associated to serious human disease. A vaccine has proved difficult to obtain so far, and current opinions agree that multi-antigen combinations may be required to induce optimal protective responses. In order to identify new potential vaccine candidates, we recently screened the Chlamydia pneumoniae (Cpn) genome and described 53 recombinant proteins which elicited antibodies binding to purified Cpn cells. We now report that six proteins in this group can also induce in vitro neutralizing antibodies. Antibody specificity for the corresponding antigens was assessed by immunoblot analysis of 2DE Cpn protein maps. Furthermore, four of the six in vitro neutralizing antigens (Pmp2, Pmp10, OmpH-like and enolase) could inhibit Cpn dissemination in a hamster model. The results show that these Cpn proteins are immunoaccessible in infectious EBs, and recommend further investigation on their value as vaccine components.

Animals↗
PubMed2005

Safety and efficacy of two types of influenza vaccination in heart transplant recipients: a prospective randomised controlled study.

BACKGROUND: Influenza may cause severe disease in immunosuppressed patients. Different vaccines have been proved to be efficacious to prevent influenza in tranplant recipients. Since the last five years the addition of adjuvants to improve the immune response to vaccine preparations has been proposed and evaluated. In this study, two antigenically identical vaccines, but different for the presence of adjuvants were randomised among a cohort of heart transplant recipients to evaluate their safety and immunogenicity. METHODS: 58 patients, receiving an heart transplant more than 6 months before, were randomised to receive one shoot vaccination with Fluad (containing the MF59 adjuvant) or Agrippal (no adjuvant added) or to enter the control, not-vaccinated, group. The immune response to influenza was evaluated separately for type A and type B viruses and for the IgG and the IgM antibodies. Patients were clinically evaluated at least monthly up to 6 months. RESULTS: Influenza symptoms were reported by 33% of patients receiving Fluad, 29% of the Agrippal and 63% of the control group. 4 episodes of acute myocardial rejection >/=3A were identified without difference between the three groups. CONCLUSIONS: The superior efficacy of vaccines containing adjuvants was not found and the data clearly confirmed that vaccination against influenza is safe and effective in heart transplant recipients. The use of vaccine containing adjuvant substances do not ameliorate the clinical performance of the immunisation suggesting that less expensive influenza vaccine preparation without adjuvant substances could be equally useful to protect heart transplant recipients.

Adult↗
PubMed2005

Molecular detection of Treponema denticola and Porphyromonas gingivalis in carotid and aortic atheromatous plaques by FISH: report of two cases.

Treponema denticola and Porphyromonas gingivalis have been identified in atheromatous plaques of two patients suffering from atherosclerosis by PCR and fluorescence in situ hybridization (FISH). The use of the FISH technique suggested that these periodontopathic micro-organisms might be metabolically active within the wall of arteries, under the atherosclerotic lesion.

Aged↗
PubMed2005

Comparative evaluation of three different ELISA methods for the diagnosis of early culture-confirmed Lyme disease in Italy.

In this study the raising and development of the immune response to Borrelia burgdorferi infection in 45 Italian patients suffering from culture-confirmed Lyme borreliosis erythema migrans was investigated. A total of 95 serially collected serum samples were tested by using three different commercial ELISAs: recomWell Borrelia (Mikrogen), Enzygnost Borreliosis (DADE Behring) and Quick ELISA C6 Borrelia (Immunetics). The sensitivities of the ELISAs were as follows: Enzygnost Borreliosis IgM, 70.5 %; Quick ELISA C6 Borrelia, 62.1 %; recomWell Borrelia IgM, 55.7 %; recomWell Borrelia IgG, 57.9 %; and Enzygnost Borreliosis IgG, 36.8 %. In order to compare the specificity values of the three ELISAs, a panel of sera obtained from blood donors (210 samples coming from a non-endemic area and 24 samples from an endemic area) was tested, as well as sera from patients suffering from some of the most common biological conditions that could result in false-positive reactivity in Lyme disease serology (n = 40). RecomWell Borrelia IgG and recomWell Borrelia IgM were the most specific (97.1 % and 98.9 %, respectively), followed by Quick ELISA C6 Borrelia (96.7 %). Enzygnost Borreliosis IgG and IgM achieved 90.1 % and 92.3 % specificity, respectively. Sera that gave discrepant results when tested by the three ELISAs were further analysed by Western blotting.

Borrelia burgdorferi↗
PubMed2005

Evaluation of LIAISON Treponema Screen, a novel recombinant antigen-based chemiluminescence immunoassay for laboratory diagnosis of syphilis.

The purpose of this study was to evaluate the diagnostic performance of LIAISON Treponema Screen (DiaSorin, Saluggia, Italy), a new automated chemiluminescence immunoassay (CLIA), in comparison with that of rapid plasma reagin (RPR) and the following currently used treponemal tests: hemagglutination test (TPHA), immunoenzymatic assay (EIA), and Western blot (WB). First, a retrospective study was performed with a panel of 2,494 blood donor sera, a panel of 131 clinical and serologically characterized syphilitic sera, and 96 samples obtained from subjects with potentially interfering diseases or conditions. A prospective study was also performed by testing 1,800 unselected samples submitted to the Microbiology Laboratory of the St. Orsola Hospital in Bologna, Italy, for routine screening for syphilis. As expected, RPR was the least specific method, especially when potentially cross-reacting sera were tested. On the contrary, all of the treponemal tests proved to be very specific (99.9%) and they performed with the following sensitivities: 100% (WB), 99.2% (CLIA), 95.4% (EIA), and 94.7% (TPHA).

Antigens, Bacterial↗
PubMed2005

Immunological evaluation and cellular location analysis of the TprI antigen of Treponema pallidum subsp. pallidum.

The TprI antigen of Treponema pallidum subsp. pallidum is a putative virulence factor predicted to be located in the outer membrane of the syphilis spirochete. In this study, we analyzed the immune response against TprI and its subunits in sera collected both from rabbits experimentally infected with the Nichols strain and from patients with syphilis, showing a different pattern of reactivity toward the antigen in these two groups of samples. The protective ability of recombinant TprI and its hypothetical outer membrane location were also investigated. Although no rabbit was protected after challenge, immunoelectron microscopy results, to be further investigated, were compatible with the outer membrane location of the antigen.

Animals↗
PubMed2005

Comparative evaluation of two enzyme linked immunosorbent assay methods and three Western Blot methods for the diagnosis of culture-confirmed early Lyme borreliosis in Italy.

This study investigated the onset and development of the immune response to Borrelia burgdorferi infection in 30 Italian patients with culture-confirmed Lyme Borreliosis in the stage of erythema migrans (EM). All patients received antimicrobial treatment when entering the study and were prospectively evaluated monthly for up to 30 days after enrolment. A total of 60 serially collected serum samples were tested by using two different commercial enzyme-linked immunosorbent assays (ELISAs): Anti-Borrelia plus VlsE ELISA, Euroimmun, and the synthetic peptide-based ELISA, Quick ELISA C6, Immunetics. Sixty-five potentially cross-reacting sera were also tested. Anti-Borrelia plus VlsE ELISA IgG was far more sensitive than Quick ELISA C6 (56.6% and 33.3%, respectively). Moreover, considering that 17 additional sera from the first bleeding group of Lyme disease patients were IgM positive when tested by Anti-Borrelia plus VlsE IgM, the sensitivity of Anti-Borrelia plus VlsE as a whole system rose to 85.0%. Nevertheless, due to the specificity values of Anti-Borrelia plus VlsE ELISA identified in this study (98.5% for IgG and 78.5% for IgM), the need of a confirmatory test for the diagnosis of Lyme disease remains. All the sera were also tested by two different commercial Western Blot (WB) assays: Euroline-WB against Borrelia, Euroimmun, and Qualicode B. burgdorferi WB, Immunetics, in comparison with a multispecies "home made" WB. Performances of the three WB methods for the detection of IgM were very similar. On the contrary, these WBs performed with different values of sensitivity and specificity when IgGs were evaluated. The most sensitive method was the "home-made" WB IgG (71.7%), followed by the Euroline-WB IgG against Borrelia (68.3%). Qualicode B. burgdorferi WB IgG demonstrated to be only 26.6% sensitive. Both "home-made" WB IgG and Qualicode B. burgdorferi WB IgG were 100% specific, whereas Euroline-WB IgG against Borrelia scored 12 cross-reacting samples as borderline, showing a specificity value of 80.0%.

Adult↗
PubMed2005

Treponema denticola infection is not a cause of false positive Treponema pallidum serology.

It has long been assumed that parodontal disease can be a cause of false positive results in syphilis serology, but so far there are no definitive data supporting this hypothesis. In this study we tested 250 serum samples obtained from blood donors. All of them were negative when routinely screened for antibodies against Treponema pallidum. Then, all these samples were tested by immunoenzymatic (ELISA) and Western Blot (WB) assays to investigate reactivities against T. denticola. Thirteen samples showed a strong positivity when tested by both methods. When tested by WB against T. pallidum no sample met the positivity criteria. Nevertheless, bands with molecolar weights of about 30-35 KDa (endoflagellar core antigens) were recognized. All the 13 subjects serologically T. denticola positive underwent oral clinical and radiological observation: all showed a very poor parodontal status (CPSS > 103). Eleven crevicular fluid samples out of the total of 13 patients were T. denticola positive by Real Time PCR carried out using a LightCycler system. In this study we demonstrated that the presence of T. denticola in the crevicular fluid samples obtained from patients with a severe periodontal status and/or a positive serology against T. denticola is not a cause of false positive results in syphilis serology.

Antibodies, Bacterial↗
PubMed2004

A case of leptospirosis simulating colon cancer with liver metastases.

We report a case of a 61-year-old man who presented with fatigue, abdominal pain and hepatomegaly. Computed tomography (CT) of the abdomen showed hepatomegaly and multiple hepatic lesions highly suggestive of metastatic diseases. Due to the endoscopic finding of colon ulcer, colon cancer with liver metastases was suspected. Biochemically a slight increase of transaminases, alkaline phosphatase and gammaglutamyl transpeptidase were present; alpha-fetoprotein, carcinoembryogenic antigen and carbohydrate 19-9 antigen serum levels were normal. Laboratory and instrumental investigations, including colon and liver biopsies revealed no signs of malignancy. In the light of spontaneous improvement of symptoms and CT findings, his personal history was reevaluated revealing direct contact with pigs and their tissues. Diagnosis of leptospirosis was considered and confirmed by detection of an elevated titer of antibodies to leptospira. After two mo, biochemical data, CT and colonoscopy were totally normal.

Colonic Neoplasms↗
PubMed2004

Production of tumor necrosis factor alpha by Treponema pallidum, Borrelia burgdorferi s.l., and Leptospira interrogans in isolated rat Kupffer cells.

Stimulation of isolated rat Kupffer cells by viable Leptospira interrogans, Treponema pallidum and Borrelia garinii elicited cellular responses resulting in the release of different tumor necrosis factor alpha (TNF-alpha) levels, depending on the spirochetes. L. interrogans induced TNF-alpha levels higher than those achieved with B. garinii and T. pallidum (in this order), but lower than the levels achieved with lipopolysaccharide (LPS). In contrast to L. interrogans, pretreatment of borreliae and treponemes with polymyxin B did not substantially diminish the ability of B. garinii and T. pallidum to stimulate Kupffer cells. Purified T. pallidum lipoproteins TpN47, TmpA, TpN15-TpN17, and B. garinii OspA induced TNF-alpha responses comparable to that achieved by LPS. This response was almost insensitive to the action of polymyxin B.

Animals↗
PubMed2004

Experimental infection by Chlamydia pneumoniae in the hamster.

We report that intraperitoneal injection of Chlamydia pneumoniae purified elementary bodies (EBs) in the hamster causes a systemic infection allowing the isolation of viable chlamydiae from several organs for several days post-infection (p.i.). In particular, spleen infection occurred up to Day 7 p.i. in 100% of animals. Systemic infection probably occurs via macrophages as intraperitoneally injected chlamydiae which are taken up by the hamster macrophages remain viable and can infect in vitro cell cultures. Immunization of 18 hamsters with heat-inactivated purified EBs, completely protected the spleens of 16 animals and substantially reduced infection levels in the remaining two. This model, therefore, provides a robust screening tool for the assessment of the protective activity of potential vaccine candidates. In a pilot study on five recombinant antigens recently described as EB surface proteins, three gave results undistinguishable from non-immunized, or mock-immunized controls; however two antigens, derived, respectively, from the product of the lcrE gene (a component of the putative TTSS of C. pneumoniae) and the product of Cpn0498 open reading frame, proved to be capable of inducing protective immune responses.

Animals↗
PubMed2003

Phagocytosis of Treponema pallidum and reactive oxygen species production by isolated rat Kupffer cells.

The in vitro phagocytosis of viable Treponema pallidum subsp. pallidum by isolated rat Kupffer cells, studied by immunofluorescence staining of Kupffer cells-associated bacteria, showed that ingestion of live, unopsonized treponemes was slow: in fact, Kupffer cells started to be positive 1 h after infection, when only 4% of the cells presented small round fluorescent inclusion-like bodies. Thereafter, the number of positive cells progressively increased with time: 7%, 17%, 36%, and 69% of Kupffer cells were positive, respectively, 2, 4, 6 and 8 h after infection. Opsonization of T. pallidum with human immune serum did not substantially modify the percentage (8%) of Kupffer cells ingesting T. pallidum 1 h after infection, whereas opsonization significantly ( P<0.01) increased phagocytosis after 2, 4 and 6 h of incubation, when 44%, 58%, and 68% of Kupffer cells were positive, respectively. At 8 h after infection of Kupffer cells by opsonized T. pallidum, 75% of the cells were positive by immunofluorescence. Heat-inactivation of T. pallidum slightly enhanced phagocytosis. In contrast, opsonization of heat-inactivated spirochetes with specific antibodies significantly ( P<0.01) increased the phagocytosis of bacteria by Kupffer cells, beginning as early as 30 min after infection, when 65% of the cells were positive by immunofluorescence. The reactive oxygen species (ROS) production by Kupffer cells following incubation with spirochetes was also determined by chemiluminescence. Treponemes induced an oxidative burst in Kupffer cells in a dose-dependent manner and the generation of ROS was already detectable 20 min after the exposure of the Kupffer cells to treponemes and peaked at 35 min of incubation. Live, as well as live and opsonized, and heat-inactivated treponemes, induced an O(2)(-) production lower than that induced by heat-inactivated and opsonized spirochetes.

Animals↗