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B Bizzini

Publications and source records attributed to B Bizzini.

At least 73 records · Page 4Linked to original sources
PubMed1990

Monitoring of the response of elderly individuals to pneumococcal vaccination with the aid of a novel ELISA.

An ELISA for assessing pneumococcal anticapsular antibodies in human sera is described. Sensitization was carried out by adding to avidin-coated polystyrene plates biotinylated capsular polyosides. This ELISA was used for the determination of anticapsular antibody levels in pre- and post-immunization sera from 20 elderly individuals. The anticapsular antibody titres differed significantly in sera taken prior to and after vaccination. Eighteen of the 20 sera tested showed mean fold increases of the antibody level greater than 2 (2.1 to 21.0) as a result of vaccination. Since morbidity and mortality rates from S. pneumoniae infections are high in the elderly, immunization should be systematically performed. However, the elderly subject is frequently immunosuppressed, and it is therefore advisable to control the result of the vaccination, using a simple procedure, such as the one described here.

Aged↗
PubMed1990

Tetanus toxin blocks potassium-induced transmitter release and rearrangement of intramembrane particles at pure cholinergic synaptosomes.

We have studied the action of tetanus toxin on the release of acetylcholine from a subcellular fraction of cholinergic nerve terminals (synaptosomes) isolated from the Torpedo electric organ. We have also studied the morphological changes induced by chemical stimulation on the presynaptic plasma membrane of poisoned synaptosomes. These changes were studied by means of freeze-fracture techniques. We found that tetanus toxin blocks the release of acetylcholine from isolated nerve terminals in a dose-dependent manner. The maximal inhibition is achieved at a concentration of 12.5 nM in 10 min. This effect is prevented by tetanus toxin antiserum. Tetanus toxin also blocks the rearrangement of intramembrane particles at plasma membrane of poisoned synaptosomes, specifically the decrease of small (less than or equal to 9.5 nm diameter) intramembranous particles at the protoplasmic hemimembrane leaflet and the increase of large (greater than 9.5 nm diameter) intramembrane particles at the external hemimembrane leaflet induced by potassium stimulation. These results suggest that intramembrane particle rearrangement could be related to acetylcholine secretion.

Acetylcholine↗
PubMed1990

Fragment A-B of tetanus toxin does not block neuromuscular transmission in the goldfish.

While 4 micrograms of Fragment A-B of tetanus toxin (which lacks the binding site for nervous tissue) causes flaccid paralysis and death in mice, 26 micrograms has no toxic effect in goldfish. Antibodies to either A-B or to fragment C (which contains the binding site) block the paralytic effect of whole toxin in goldfish. It is concluded that binding is necessary for the neuromuscular blocking action of the toxin in goldfish.

Animals↗
PubMed1990

Use of live Saccharomyces cerevisiae cells as a biological response modifier in experimental infections.

A short-term oral administration of live Saccharomyces cerevisiae cells, strain Sillix Hansen DSM 1883, resulted in enhanced resistance of mice toward infections with K. pneumoniae. S. pneumoniae and S. pyogenes A produced by intranasal inoculation. Yeast pre-treatment also increased the efficacy of antibiotic therapy in bacterial infections and of antiviral drugs in viral infections. Yeast treatment of animals stimulated phagocytosis, activated the complement system and induced interferon which are likely to represent the main mechanisms of action whereby pretreatment of mice with live S. cerevisiae cells increases resistance to infection. It is concluded that preventive administration of live Saccharomyces cerevisiae cells should be used for increasing resistance to bacterial infections, in particular of the respiratory tract, or to viral infections, as well as an adjunct to antibiotic and antiviral drug therapy.

Adjuvants, Immunologic↗
PubMed1990

Screening of tetanus antibodies with the aid of dot-enzyme-linked immunosorbent assay (Dot-ELISA). Validation of the results using standard ELISA and passive hemagglutination test.

A Dot-ELISA is described that lends itself to the screening of large series of sera in relation to tetanus antibodies. A threshold of 0.06 I.U. per ml has been chosen as representing the protective tetanus antibody level. Two hundred and fifty-four sera were assayed by conventional ELISA, passive hemagglutination test and Dot-ELISA. The results obtained using concurrently these 3 techniques were in agreement with one another and permitted us to ascribe the same sera as tested by the various techniques to the same group of sera containing a non protective antitetanus antibody level and to the same group of sera-containing a protective level. It is suggested that Dot-ELISA should be used for the assessment of the tetanus immune status of populations.

Antibodies, Bacterial↗
PubMed1989

Rapid assessment of the antitetanus immune status of a subject using Dot-ELISA.

We describe a Dot-ELISA system for the rapid, specific and reliable assessment of a subject's antitetanus immune status. The conditions for Dot-ELISA were selected to give positive reactions only for sera with antitetanus antibody titers equal to or higher than 0.06 I.U./ml, considered to represent protection when using "in vitro" methods. This Dot-ELISA method could advantageously be applied to the monitoring of vaccination campaigns, as well as for assessing the antitetanus immune status of the wounded.

Antibodies, Bacterial↗
PubMed1989

Potentiation by nonspecific immunostimulation of the efficacy of antibiotics in the treatment of experimental bacterial infections.

In the present investigation, mouse infection models with either intracellular or extracellular bacteria were designed in order to assess the effect of nonspecific immunostimulation with the C. granulosum-derived P40 immunomodulator on infection treatment, performed with doses of antibiotics achieving a low percentage of cures. The results obtained showed that nonspecific immunostimulation was able to significantly enhance antibiotic therapy efficacy. In addition, combined treatments of bacterial infections should allow for a reduction in dosages of antibiotics while at the same time, achieving increased efficacy. Possible mechanisms for the potentiating effect of nonspecific immunostimulation on antibiotic therapy effectiveness are discussed.

Adjuvants, Immunologic↗
PubMed1988

Inhibition of rabies virus infection by a soluble membrane fraction from the rat central nervous system.

This paper describes the inhibitory effect of a normal rat brain solubilized membrane preparation (RBSM-liposomes) on rabies virus infection. Rabies virus was incubated with RBSM-liposomes or their separated components (proteins, phospholipids, gangliosides) before infection of CER or neuroblastoma cells. In addition, both RBSM-liposomes and target cells were treated with enzymes prior to the infection step. All these experimental procedures showed that the active components were mainly lipids.

Animals↗
PubMed1988

Tetanus and botulinum toxins block the release of acetylcholine from slices of rat striatum and from the isolated electric organ of Torpedo at different concentrations.

Tetanus toxin, like botulinum toxin type A, blocks cholinergic synaptic transmission at the central and peripheral nervous systems. Nevertheless, the diseases induced by the two toxins are different since tetanus toxin induces a spastic paralysis and botulinum toxin elicits a flaccid paralysis. Thus, we have investigated the sensitivity of a central and a peripheral cholinergic synapse to these two toxins. We have studied the action of both poison on the release of acetylcholine from slices of the rat striatum and from the isolated electric organ of Torpedo, which is homologous to the neuromuscular junction. Acetylcholine release from the rat striatum was continuously monitored by a chemiluminescent method. The secretion of acetylcholine from the electric organ was estimated both by measuring the amplitude of the evoked electrical discharge from stacks of electroplaques, and by continuously monitoring the neurotransmitter release from isolated nerve terminals. Tetanus toxin blocks the electrical discharge of electric organ prisms, and also impairs the release of acetylcholine from the Torpedo electric organ nerve endings. Our results on acetylcholine release show that tetanus toxin is more potent than botulinum toxin type A at the central cholinergic synapse (tetanus/botulinum toxins potency ratio about 100-200) whereas botulinum toxin is the most potent at the peripheral cholinergic synapse (botulinum/tetanus toxins potency ratio about 100).

Acetylcholine↗
PubMed1988

Defining a region on tetanus toxin responsible for neuromuscular blockade.

Administering high doses of tetanus toxin to animals produces neuromuscular blockade. Previous studies, in which specific F(ab) antibody fragments were used to mask the 50,000 MW COOH-terminal portion of the heavy chain (fragment c) on the toxin molecule, have shown that the paralyzing effect of the toxin was most probably located in an area comprising the light chain and the 50,000 MW NH2-terminal portion of the heavy chain (Fragment Ibc). In our study, the toxin was also complexed with F(ab) fragments directed to the light chain (alpha), heavy chain (beta), beta minus IIc, and with monoclonal antibodies to epitopes on IIc and beta minus IIc. Investigating the effect of the resulting complexes both in mice and on the sphincter pupillae muscle in rabbits permitted us to circumscribe further the tetanus toxin neuromuscular blocking activity in a region of the NH2-terminal fragment (Mr = 50,000) of the heavy chain (fragment beta minus IIc). Our results are consistent with the assumption that the beta minus IIc fragment is critical for the neuromuscular blockade activity of tetanus toxin. However, it cannot be ruled out that both the peripheral and central effects of the toxin result from the same portion of the toxin molecule, the nature of the action depending on where the toxin is carried after its introduction into the organism.

Animals↗
PubMed1988

Inter- and intrageneric transfer of Tn916 between Streptococcus faecalis and Clostridium tetani.

We report that the streptococcal resistance transposon, Tn916, is conjugally transferred to Clostridium tetani (Utrecht) in intergenic matings. Streptococcus faecalis CG180, harboring a 41-kb plasmid (pAM180) containing Tn916 (15 kb), transferred the transposon-associated tetracycline resistance (Tcr) to C. tetani in filter matings at a frequency of about 10(-4)/donor. An erythromycin resistance marker carried by pAM180 was not transferred, indicating lack of plasmid conjugation or stable inheritance of plasmid sequences. DNA extracted from C. tetani transconjugants was probed with radiolabeled Tn916 using Southern blot analysis and these results indicated that the transposon integrated at multiple host genomic sites. Tn916-carrying C. tetani strains were able to transfer Tcr to suitable recipient strains of C. tetani as well as to S. faecalis recipients. These results indicate that this transposon is able to be disseminated and expressed in obligately anaerobic gram-positive bacteria. Moreover, this system opens avenues for the implementation of transposon mutagenesis in this important pathogenic species.

Clostridium tetani↗
PubMed1988

E. coli infections of the lower urinary tract and their treatment by immunomodulation or combined immunomodulation and antigen therapy.

A model of infection by E. coli 022 of the lower urinary tract in the rat is described. The infection is characterized by the presence in the urine of a large number of E. coli (10(5)-10(7) bacteria per ml). There is pus formation in the urine. A few infected rats also exhibited prostate hypertrophy and the presence of ACB could be detected in some of the latter group. Treatment of the infected rats by the C. granulosum-derived immunomodulator P40, injected intravenously either as a single dose of 1 mg per rat 1 day after infection or as 2 fractionated doses of 0.5 mg 1 day and 3 days after infection resulted in sterilization of a significant number of urines. The interest of fractionating the dose of P40 is to reduce the incidence of prostate hypertrophy formation. Comparable results were obtained when P40 was given preventively to the rats either as a single dose 7 days before infection or as 2 fractionated doses 7 days and 1 day before infection. The association of a single preventive dose of 1 mg of P40 given 7 days before infection by administering a suspension of heat-killed E. coli 022, as a specific antigen, 1 day after infection permitted the sterilization of urines in all infected rats and prostate hypertrophy formation did not occur.

Adjuvants, Immunologic↗
PubMed1988

The Corynebacterium granulosum-derived P40 immunomodulator exerts a synergistic effect on the activity of antiviral drugs in the treatment of experimental viral infections.

Comparative studies have been carried out on the effects on 2 viral-infection models (Herpes virus and influenza virus) of treatments consisting of either C. granulosum-derived immunomodulator P40, or of vidarabin or amantadine as antiviral drugs, or of combinations of vidarabin or amantadine with P40. According to the modalities of administration of the P40 or of the antiviral drugs, the anti-infectious effect was more or less marked. In contrast, the combinations of P40 and antiviral drugs did not result in a cumulative effect but in significant synergy of the effects of each component of the treatments.

Adjuvants, Immunologic↗
PubMed1988

Potentiating the effectiveness of influenza vaccination by a combined immunostimulation with P40 immunomodulator: an experimental study in mice.

Influenza vaccination is highly desirable in view of the epidemic character of this infection and of the severity that it can assume in high-risk and in elderly persons. Its effectiveness varies from 40-90%. Moreover, strains can undergo an antigenic drift in the course of an epidemic. Consequently, reinforcement of the immunogenicity of vaccines is required for achieving a more complete immunization coverage. Combination of an immunomodulator, the C. granulosum-derived P40 fraction, with influenza vaccine resulted in significant potentiation of vaccine immunogenicity. In addition to its adjuvant action, the P40 is also likely to exercise a protective effect by stimulating the non-specific immune defenses of the organism.

Adjuvants, Immunologic↗
PubMed1987

ATP release from pure cholinergic synaptosomes is not blocked by tetanus toxin.

Tetanus toxin (TeTx) is a neurotransmission impairing toxin that acts on several neurotransmitter systems. TeTx also inhibits the K+-induced release of acetylcholine (ACh) from synaptosomes isolated from the electric organ of Torpedo. Neither the membrane potential and depolarization, nor the depolarization-induced calcium uptake into cholinergic nerve terminals is modified after TeTx poisoning. On the other hand, it is known that, when cholinergic nerve terminals are stimulated, there is a release of ATP associated with the release of ACh. We have explored the action of TeTx on this co-release, and have found that there is no action of TeTx on the nucleotide release. Thus, TeTx blocks ACh release without modifying ATP release.

Acetylcholine↗
PubMed1987

Relation between protective potency and specificity of antibodies in sera of tetanus immunized individuals.

Out of 157 human sera analyzed for antitetanus antibody content by ELISA, 13 turned out to contain only anti-BIIb antibodies, of which 8 proved to be neutralizing. Of these, the 3 sera 303, 306 and 312 together with a commercially available standard preparation of human antitetanus immunoglobulins were further analyzed as to their antibody composition by ELISA using plates sensitized with either the toxoid or various tetanus toxin-derived fragments. It was verified that the protective potency of these antisera was related mainly to their anti-BIIb antibody content. Adsorption experiments confirmed that anti-BIIb antibodies were primarily involved in toxin neutralization, although the presence of high levels of both anti-alpha and anti-Ibc antibodies could confer neutralizing capacity on the sera. A rabbit antiserum raised with the BIIb fragment resulted in a neutralizing antiserum that allowed us to calibrate the ELISA with the anti-BIIb antibodies as International Units.

Adolescent↗
PubMed1987

Immunity to tetanus: tetanus antitoxin and anti-BIIb in human sera.

Immunity to tetanus was investigated in 157 individuals aged between 1 and 77 years using, for the evaluation of both tetanus antitoxin and antibody to fragment BIIb (anti-BIIb), an easily performed ELISA that gave reproducible results. Among these people 72% were protected against tetanus (tetanus antitoxin titres greater than 0.06 IU ml-1). Anti-BIIb titres greater than 0.15 U ml-1 were found in 75% of the males vs 57% of the females (P less than 0.02) with marked variations according to age. Furthermore, 13 out of 41 individuals with antitoxin titres less than 0.06 IU ml-1 (not protected against tetanus) were found to have anti-BIIb titres greater than 0.15 U ml-1. These data raise questions as to the significance and protective effect of anti-BIIb against tetanus.

Adolescent↗