1,721,012 research outputs found
Epidemiological study of Staphylococcus strains isolated from clinical material in 24 italian hospitals
No full textMODULATORY EFFECTS OF HEN EGG-WHITE LYSOZYME ON IMMUNE RESPONSE IN MICE
No full textThe effect of her egg-white lysozyme (HEWL) on immune response was evaluated by measuring antibody-producing cells and circulating antibodies in mice inoculated with the test antigen (SRBC or BSA) and HEWL at the same time but in a separate body area. HEWL caused a premature decline in SRBC-specific plaque forming cells (PFC) and a reduction in the total amount of these cells. HEWL inhibited antibody production against BSA in the primary response, but was devoid of any effect on the secondary response elicited in the same mice by a second inoculation of the test antigen. The inhibitory effect of HEWL was dose-dependent, being maximal with 300 micrograms, required an enzymatically active protein and was not shown by other basic proteins. HEWL also abolished the enhancing effect of LPS and CFA on anti-BSA antibody production. The inhibitory activity of HEWL was further increased by hydrolyzed peptidoglycan. These results suggest that HEWL modulates the immune response in mice and performs this function through activation of non-specific suppression mechanism
Distribution and antibiotic susceptibility of extraintestinal clinical isolates of Klebsiella, Enterobacter and serratia spp.
No full textInhibition of Herpes simplex virus-induced cytopathic effect by modified hen egg white lysozyme
No full textHen egg-white lysozyme and three of its basic derivatives obtained by chemical modification were tested for their activity in vitro against a wild strain of herpes simplex virus type 1. Marked inhibition of the cytopathic effect was exhibited by the three chemical derivatives and the heat-inactivated lysozyme, whereas the native enzyme displayed only modest anticytopathic activity. Enzymatic activity did not appear to be necessary for the antiherpes activity of the lysozyme compounds. Instead, other properties such as their basic nature seemed to be relevant to their antiherpes effectiveness in vitro. At the concentrations used, all compounds but one had no significant effect on cell viability and growth. Some of the compounds tested caused formation of deposits on the surface of the cells. Some correlation between deposit formation and antiherpes cytopathic activity was found. The antiherpes efficacy in vitro and toxicity of the modified lysozymes were compared with those of known antiviral agents. The lysozymes were less toxic than the reference antiviral agents, and some of them were also more activ
Detection of hepatitis B virus DNA in serum using synthetic non-radioactive oligonucleotides.
No full textNationwide survey in Italy of treatment of Streptococcus pyogenes pharyngitis in children: influence of macrolide resistance on clinical and microbiological outcomes
No full textCross-reactive pseudovirus-neutralizing anti-envelope antibodies coexist with antibodies devoid of such activity in persistent hepatitis C virus infection
No full textNew Tn916-related elements causing erm(B)-mediated erythromycin resistance in tetracycline-susceptible pneumococci
No full textObjectives: To analyse the as yet unexplored genetic elements encoding erm(B)-mediated erythromycin
resistance in tetracycline-susceptible pneumococci.
Methods: Sixteen Streptococcus pneumoniae clinical isolates sharing erm(B)-mediated erythromycin
resistance and susceptibility to tetracycline were used. Gene detection was performed by PCR using
both established and specially designed primers. S. pneumoniae R6, Streptococcus pyogenes 12RF
and Enterococcus faecalis JH2–2 were used as recipients in mating experiments.
Results: Of the 16 test strains, 14 bore an unexpressed tet(M) gene which in 13 strains had a genetic
linkage with erm(B). Three isolates yielded a 3.2 kb and 10 an 11.9 kb erm(B)/tet(M) amplicon. The
former three showed genetic organizations similar to that of the composite element Tn3872, where the
erm(B)-carrying Tn917 transposon is inserted into a Tn916-like element. Of the latter 10 isolates, 9
showed genetic organizations substantially overlapping with that of Tn6002, a newly sequenced
erm(B)-containing Tn916-related transposon. The tenth isolate carried a novel composite element
(designated Tn6003) resulting from the insertion into a Tn6002-like transposon of a fragment [designated
macrolide–aminoglycoside–streptothricin (MAS) element] containing a second erm(B) (lacking
the stop codon) and a variant of the aadE–sat4–aphA-3 cluster. The two tet(M)-negative isolates had
different Tn3872-related elements, one containing a complete and one a deleted MAS fragment.
Conjugative transfer was obtained from donors carrying Tn6002-related elements, not from donors
carrying Tn3872-related elements.
Conclusions: In tetracycline-susceptible pneumococci with erm(B)-mediated erythromycin resistance,
the erm(B) gene is carried on a variety of Tn916-related genetic elements either lacking tet(M) or, more
often, carrying an unexpressed tet(M) gene
Diverging effects of human recombinant anti-hepatitis C virus (HCV) antibody fragments derived from a single patient on the infectivity of a vesicular stomatitis Virus/HCV pseudotype
No full textHepatitis C virus (HCV) is the major causative agent of blood-borne non-A, non-B hepatitis. Although a strong humoral response is detectable within a few weeks of primary infection and during viral persistence, the role played by antibodies against HCV envelope glycoproteins in controlling viral replication is still unclear. We describe how human monoclonal anti-HCV E2 antibody fragments isolated from a chronically HCV-infected patient differ sharply in their abilities to neutralize infection of HepG2 cells by a vesicular stomatitis virus pseudotype bearing HCV envelope glycoproteins. Two clones were able to neutralize the pseudotype virus at a concentration of 10 μg/ml, while three other clones completely lacked this activity. These data can explain the lack of protection and the possibility of reinfection that occur even in the presence of a strong antiviral antibody response
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