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Biomedical subjects

V Sambri

Publications and source records attributed to V Sambri.

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

The epidemiology of Lyme borreliosis in Italy.

Erythema migrans was described in Italy only in 1971 although Italian dermatologists were familiar with it a long time before. In 1983, the first case of Lyme borreliosis with multisystem involvement was identified. The endemic areas in Italy are the Ligurian coast, the province of Friuli Venezia Giulia, and the region surrounding the town of Bologna. In Liguria, the incidence of Lyme disease is about 17/100,000 inhabitants per year. Serosurveys of the general population and of sentinel animals were useless in determining the diffusion of Lyme borreliosis whereas evaluation of people at risk of tick bites and patients with suggestive signs or symptoms was more effective. Among the clinical manifestations of Lyme borreliosis, cutaneous involvement is four times more frequent than neuroborreliosis and arthritis is less frequent in Italy than in the USA.

Humans↗
PubMed1992

Differential cleavage of surface proteins of Borrelia burgdorferi by proteases.

The differential cleavage of surface proteins of Borrelia burgdorferi IRS strains by several proteases was examined. Proteinase K, trypsin, chymotrypsin and thermolysin all cleaved the outer surface protein B (OspB) to undetectable levels by Coomassie Brilliant Blue staining, whereas some residual protein was detected by immunoblotting with polyclonal and monoclonal antibodies. Not even antigenic fragments were detectable by immunoblotting with 1A8 monoclonal antibody reactive with OspB. Less effective or ineffective was the cleavage of OspB by V8 protease and proteinase A, respectively. The outer surface protein A was cleaved only by proteinase K. The effect of trypsin on borreliae viability and adhesion to cultured cells was also studied. The trypsin treatment of borreliae did not impair the viability of organisms which continued to synthesize the cleaved OspB. The attachment of B. burgdorferi to HEp-2 cells was reduced by 41% after treatment with trypsin, whereas preincubation of borreliae with monoclonal antibody 1A8 and guinea pig immune serum reduced the adhesion of borreliae to the cells by 32% and 87%, respectively.

Antibodies, Monoclonal↗
PubMed1991

Development of transplantable ascites tumours which continuously produce polyclonal antibodies in pristane primed BALB/c mice immunized with bacterial antigens and complete Freund's adjuvant.

Bacterial immunogens (whole cells of Borrelia burgdorferi, elementary bodies of Chlamydia trachomatis and purified proteins of 22 and 24 kDa of Borrelia hermsii) were emulsified with an excess of complete Freund's adjuvant and injected (i.p.) on days 0, 7, 14 and 21, into BALB/c mice treated with pristane on day 6. This procedure induced the development of antibody-producing ascites tumours which could be serially transplanted in pristane-conditioned mice. Ascites tumours continued to yield a consistent amount of specific polyclonal antibody after ten serial transplants. The method described appears to be particularly useful for the production of a large amount of antibody when only small amounts of immunogen are available.

Animals↗
PubMed1991

Susceptibility of iron-loaded Borrelia burgdorferi to killing by hydrogen peroxide and human polymorphonuclear leucocytes.

Borrelia burgdorferi grew more slowly in iron-depleted than in iron-sufficient media. The addition of increasing concentrations of iron stimulated borrelial growth and resulted in the intracellular accumulation of this element. Compared with iron-starved borrelia, iron-enriched organisms showed enhanced sensitivity to hydrogen peroxide. Intracellular iron-content did not, however, influence susceptibility to killing by human polymorphonuclear leucocytes [corrected].

Blood Bactericidal Activity↗
PubMed1991

Immunological characterization of a low molecular mass polypeptidic antigen of Borrelia burgdorferi.

The presence of a low molecular mass polypeptidic antigen in Borrelia burgdorferi was described. The protein was exposed at the bacterial surface since it was clearly identified by mAb 3H4 using the immunofluorescence test performed with living bacteria. This antigen was cleaved by proteinase K treatment, whereas it was resistant to the action of chymotrypsin, trypsin and thermolysin. Western blotting analysis of the immunological reactivity of this antigenic structure performed using monoclonal antibody, mouse-immune ascitic fluids raised against B. burgdorferi and other spirochetes, sera from patients with Lyme disease and other infirmities in which false positive results in serological tests for B. burgdorferi have been described, demonstrated that this protein expresses only species-specific epitopes which may be recognized during human B. burgdorferi infections.

Animals↗
PubMed1991

In-vitro activity of roxithromycin against Chlamydia trachomatis.

Ten Chlamydia trachomatis isolates were tested for their sensitivity to roxithromycin, in comparison with erythromycin and tetracycline. The minimum inhibitory and minimum bactericidal concentrations of roxithromycin ranged from 0.03-0.12 and 0.25-1 microg/ml, respectively.

Anti-Bacterial Agents↗
PubMed1991

Comparative ability of various detergents to extract proteins of Borrelia burgdorferi and Borrelia hermsii.

Borrelia burgdorferi and Borrelia hermsii were treated with the following detergents: sodium dodecyl sulphate (SDS), N-lauryl sarcosine (Sarkosyl) and Triton X-100, and the soluble and insoluble fractions obtained after each detergent treatment were examined by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Sarkosyl as well as SDS solubilized all Borrelia proteins, whereas Triton X-100 treatment selectively solubilized the majority of other borrelial proteins, leaving two proteins of 41 kDa and 66 kDa in Borrelia burgdorferi and one protein of 39 kDa in Borrelia hermsii associated with the Triton X-100 insoluble fraction.

Bacterial Proteins↗
PubMed1990

In-vitro susceptibility of Borrelia burgdorferi and Borrelia hermsii to ten antimicrobial agents.

The in-vitro activity of ten antimicrobial agents against four strains of Borrelia burgdorferi originating both in the United States and Europe and against one isolate of B. hermsii was investigated. Ceftriaxone, erythromycin and roxithromycin were the most active drugs against both Borrelia species studied, with minimum bactericidal concentrations ranging from 0.015 micrograms/ml to 0.125 micrograms/ml.

Anti-Bacterial Agents↗
PubMed1990

Survival of Borrelia burgdorferi in different electroporation buffers.

Electroporation consists in the application of an electric field through a cell membrane until the membrane itself develops transient pores. This technique has been used to insert external macromolecules into both eukaryotic and prokaryotic cells. In this study we investigated the survival ratio of Borrelia burgdorferi, the Lyme disease spirochete, under different electroporation conditions.

Borrelia burgdorferi Group↗
PubMed1989

Serological response to chlamydial infection in sheep, studied by enzyme-linked immunosorbent assay and immunoblotting.

Two enzyme-linked immunosorbent assays (ELISA) using highly purified elementary bodies (EB) of Chlamydia psittaci A/22 strain (ovine) or 6BC strain (psittacine) were set up for the detection of antichlamydial antibodies in sheep. No significant differences were observed between the two ELISAs, whereas these tests proved to be more sensitive than complement fixation test and showed a good correlation (r = 0.75) with immunofluorescence assay. The periodate treatment of chlamydial antigens modified the results of serological responses studied by ELISA, depending on the sera. The average reduction of ELISA values by periodate was 28%, ranging between 5% and 65%. The immunoblot analysis of sheep sera showed high cross reactivity between the polypeptides of A/22 and 6BC strains. However, some differences were observed. The major outer membrane protein (MOMP) of 6BC strain was recognized at different molecular weight position (40,000 kDa) in comparison with the MOMP of A/22 strain (38,000 kDa). In addition, a clear band of 97,000 kDa was detected by all sheep sera tested with A/22 strain. This band was undetectable in the blots performed with 6BC strain.

Animals↗
PubMed1989

In-vitro activity of ofloxacin against Chlamydia trachomatis.

The in-vitro activity of ofloxacin was evaluated against recently isolated Chlamydia trachomatis strains from patients suffering from non-gonococcal urethritis. The minimal inhibitory concentration (MIC) proved to be 1 mg/l against 8 of the 10 strains assayed (the MICs for the other two strains were 0.5 and 2 mg/l). The data obtained confirm that ofloxacin is active against Chlamydia trachomatis at concentrations achievable with the routine dosage regimen. The drug may thus be regarded as potentially useful for the treatment of non-gonococcal urethritis due to Chlamydia.

Chlamydia trachomatis↗
PubMed1989

Influence of several experimental parameters on inter and intra specific mating process efficiency.

In this study we investigated the influence that several experimental parameters may product on the mating process efficiency. We used the ordinary mating technique described by other authors and we examined the effect of temperature, media and plasmid size on the number of recipient cells transformed by mating procedure. The results showed that the most important parameter influencing the efficiency of the mating transformation is the media, associated with the size of the plasmid to be transferred.

Conjugation, Genetic↗
PubMed1987

Prevalence of enteric adenovirus from acute gastroenteritis: a five year study.

Adenoviruses were detected in the stools in 459 of 3932 (11.6%) pediatric children hospitalized with acute gastroenteritis from January 1981 to December 1985. Out of the 459 adenovirus specimens 325 (8.3%) were presumptively identified as enteric adenovirus both by an adenovirus genus specific ELISA and by growth characteristics of adenovirus isolates in HEp-2 cells and in 293 cells. Enteral adenoviruses were found endemic since these viruses have been found for 5 successive years. A seasonal variation in the rates of adenovirus was also observed. Comparative data of rotavirus prevalence in the same study population are reported.

Acute Disease↗
PubMed1987

Enzyme-linked immunosorbent assay for the in-vitro detection of sensitivity of Chlamydia trachomatis to antimicrobial drugs.

A new method of testing antimicrobial activity in vitro against Chlamydia trachomatis by enzyme-linked immunosorbent assay (ELISA) was developed by using a monoclonal antibody reacting with the major outer membrane protein of C. trachomatis LGV2 serotype. ELISA was compared with standard iodine stain, with immunofluorescence assay (IFA) and immunoperoxidase assay (IPA) performed with the same monoclonal antibody as in the ELISA. The MICs and MBCs of rifampicin, oxytetracycline, erythromycin, chloramphenicol and cefazolin detected by ELISA were higher than those determined by iodine stain and slightly lower than those determined by IFA and IPA. Since ELISA was at least as informative as the previously described techniques, but more rapid and standardizable and easier to perform, the assay may be useful in measuring the antimicrobial drug susceptibility of C. trachomatis.

Anti-Bacterial Agents↗
PubMed1986

Capture-ELISA for serum IgM antibody to respiratory syncytial virus.

A four-component solid-phase capture enzyme immunoassay was set up to test for serum IgM antibody to respiratory syncytial (RS) virus and was compared with immunofluorescence assay (IFA). A total of 128 young children with acute respiratory infections were studied. Thirty-six were shown to be RS virus-positive by the detection of RS virus in nasopharyngeal secretions and 92 were RS virus-negative. A serum specimen was collected after admission to the hospital (days 0-4) and a further specimen was obtained during days 10-14. Out of 36 RS virus-positive patients, 28 (77.7%) were found to be positive for IgM by both capture-ELISA and IFA. Out of 92 RS virus-negative patients 5 (5.4%) were IgM-positive. Four false-positive results were obtained by IFA due to the presence of rheumatoid factor. The capture-ELISA was shown to be a reliable technique in detecting specific IgM antibody to RS virus.

Antibodies, Viral↗
PubMed1986

Class specific immunoglobulin response to individual polypeptides of Chlamydia trachomatis, elementary bodies, and reticulate bodies in patients with chlamydial infection.

Sera from 10 women with Chlamydia trachomatis culture positive cervicitis and sera from six men with C trachomatis positive non-gonococcal urethritis were studied for the presence of IgG, IgM, and IgA antibodies to polypeptides of C trachomatis elementary bodies and reticulate bodies using immunoblotting techniques. All the sera with IgG, IgM, or IgA immunoglobulins specific to C trachomatis recognised the major outer membrane protein (MOMP) of elementary bodies. IgG antibodies also detected several other proteins, whereas IgM immunoglobulins recognised only MOMP and proteins of 60 kD, 62 kD, and 66 kD. The IgA reacted with MOMP and the 60 kD and 62 kD proteins in elementary bodies. Class specific antibody response against the proteins of reticulate bodies was similar to that observed for elementary body antigens--with one substantial difference: no reaction was observed in the 60 kD and 62 kD positions. This suggests that 60 kD and 62 kD proteins are deficient in reticulate bodies.

Antibodies, Bacterial↗