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Biomedical subjects

F Galdiero

Publications and source records attributed to F Galdiero.

At least 55 records · Page 3Linked to original sources
PubMed1986

Effect of Salmonella typhimurium porins on the cardiovascular and renal apparatus.

The cardiovascular effects of porins were evaluated using porins isolated from Salmonella typhimurium SH5014. In dogs porins depress arterial systemic pressure, vasomotor reactivity of norepinephrine and peripheral vagal stimulation. They are capable of modifying the sinocarotidal baroreceptor reactivity. In mice porins increase the cardiotoxic effects of isoprenaline, thyroxine, emetine and of p-nitrophenol. In rats porins increase the arrhythmogenic and lethal effects of BaCl2 and also give rise to renal lesions, probably at the tubular level.

Animals↗
PubMed1985

Modifications of surface properties in some enteropathogenic serogroups of Escherichia coli.

Studies have been carried out on protein and fatty acid patterns present in the outer layers of E. coli strains which are considered pathogenic in relation to their serogroup. The patterns were related to surface properties of hydrophobicity of the same cells and to their resistance to phagocytosis. The results obtained demonstrate the presence in the pathogenic serogroups of a proteic band of high molecular weight as well as differences in the percentages of fatty acids with respect to the non-pathogenic serogroups. Furthermore, these serogroups are more resistant to phagocytosis; this resistance seems to be correlated to a greater surface hydrophilia of the pathogenic serogroups, leading to different relations of the lipidic and protein fraction of the outer layers.

Bacterial Outer Membrane Proteins↗
PubMed1985

Cytotoxic antibody dependent cells in mice experimentally infected with Brucella abortus.

In this study we investigated the cytotoxic activity mediated by antibody dependent cells (K cell) in C57BL/6 mice experimentally infected with Brucella abortus. The involvement of the K cells in experimental infection from Brucella was studied by evaluating the bacteriolysis in the presence of specific antibodies. After 3 h of incubation, approximately 30 +/- 3% of the labeled Brucellae undergo lysis, whereas the presence of lymphocytic populations alone, or of a specific decomplemented serum, determines a lysis of 5 +/- 3%. Cytotoxic antibody dependent activity of purified lymphomonocytic populations (ADCC) evaluated against cells labeled with 51Cr sensitized with specific antibodies obtained from mice is considerably increased in mice experimentally infected with Brucellae with respect to that present in non-infected mice. The increased activity begins to manifest itself 5 to 7 days after inoculation of the Brucellae reaching a maximum on the 10th day. The same results were obtained in the lymphocytic populations prepared from normal animals and those infected by Brucellae searching for K cells with the ability to form rosettes (EA-RFC).

Animals↗
PubMed1984

Activation of complement system by porins extracted from Salmonella typhimurium.

The effect of porins purified from Salmonella typhimurium on the complement system was investigated both in vitro and in vivo. Incubation of porins with either human or guinea pig serum resulted in the consumption of the total complement activity when an amount of porins ranging from 8 to 10 micrograms per 100 microliters of serum was used. The activation of the complement system was temperature dependent, suggesting an active process rather than passive adsorption of the complement components by porins. In addition, the activation had a fast kinetic and proceeded mainly through the classical pathway. This conclusion is supported by the consumption of C1s and C4 in normal human serum treated with porins and also by the depletion of C3 activity in the C1s-deficient serum which was marked only when purified C1s was added to the serum before incubation with porins. Injection of 100 micrograms of porins into guinea pigs induced profound complement consumption at 6 h postinjection that persisted up to 12 h. We conclude from this study that porins can effectively contribute to complement activation and to subsequent biological events induced by gram-negative bacteria.

Animals↗
PubMed1984

Immune response in mice and effects on cells by outer membrane porins from Salmonella typhimurium.

In this study, we describe the role of porins extracted from the outer membrane of S. typhimurium on the interaction with the host organism. The tests were performed on CD-1 mice immunized both with whole S. typhimurium cells and with purified porins. The antibody titres obtained in mice treated with purified porins and in those treated with whole Salmonella are 1/320 and 1/80 respectively. Cell-mediated response was found to be stimulated in both mice groups: our results show that T lymphocytes determine an increase in H3-thymidine incorporation and MIF production. An increase in lymphocytes with membrane immunoglobulins was observed in the lymphocyte population from the spleens of the treated mice. Purified porins added to macrophages cultures exerted a toxic effect at concentrations between 10 and 20 micrograms/ml. Subinhibiting concentrations (5 micrograms/ml) led to modifications in the surface tension of macrophages layers adhering to the slides. Moreover, subinhibiting porins concentrations were found to modify macrophage functionality as shown by evaluation of the phagocytic index and of intracellular killing, both of which were found to have diminished with respect to controls. When purified porins were added in vitro to populations enriched with T and B lymphocytes, at concentrations between 1 and 5 micrograms/ml they were found to be mitogenic with respect to B lymphocytes. The results we obtained showed that lymphocytes with IgM increase in porins tests. Eventually, purified porins added to Hela and Hep-2 cells were shown to exert a toxic effect which became detectable in the final concentration of 5 micrograms/ml and 1 micrograms/ml for Hela and Hep-2 cells respectively.

Animals↗
PubMed1982

Ion-binding properties of S-layer proteins from Bacillus subtilis.

A study was made of K+, Na+, Ca++ and Mg++ binding and ion-exchange properties of S-layer proteins from Bacillus subtilis. Our results indicate that the proteins of S-layer have two binding sites with pK of 3.17 and 2.41. To study the capacity of S-layer subunits to bind K+, Na+, Ca++ and Mg++, potentiometric titrations were performed according to Albert on proteins in solution in the presence and the absence of cations. It appears that the proteins possess dissociable groups with different affinity for various cations.

Bacillus subtilis↗
PubMed1982

Lymphocyte subpopulations in healthy and unhealthy newborn babies.

The Authors report the data of a study of lymphocyte subpopulations (T lymphocytes as rosette forming cells, B lymphocytes as surface immunoglobulin bearing cells, Ea cells as active rosette forming cells, EAC cells, with a receptor for complement, and EA cells, with a receptor for Fc fragment) in venous blood of a group of newborn babies including at term and preterm subjects and babies with and without bacterial infections. A group of healthy adults was also examined as control. Main findings were the following: a) in the group of newborn babies with infection the number of lymphocytes/microliter was higher as compared to that of newborn babies without infections and of adult controls; b) the percentage of T lymphocytes was significantly lower in the two groups of newborn but the absolute number was comparable; c) active rosette forming cells behaved as T lymphocytes; d) absolute number of B lymphocytes was significantly higher in newborn babies with infection as compared to newborn babies without infection and adult controls; e) newborn with infections showed also higher absolute number of EA rosette; f) EAC rosette behaved as T lymphocytes and active rosette forming cells. The increase of B lymphocytes in babies with infection is interpreted as an acceleration of the maturation of lymphocyte populations toward the pattern of older ages. The increase of EA rosette forming cells is tentatively interpreted as an increase of K lymphocytes fostered by infection.

Adult↗
PubMed1979

Adenovirus aggregation and preservation in extracellular environment.

The conditions of adenovirus aggregations are analyzed. Adenovirus type 2 was propagated on Hep2 cells; virion aggregation analysis was performed by sedimentation velocity on sucrose gradients. The results show that aggregation depends on: 1) Ionic strength: aggregate formation was verified between 0.005 M and 0.05 M NaCl; 2) pH: at pH 7.1 virus particles are dispersed, 90 per cent of particles are aggregated at pH 4--5; at pH lower than 4 aggregation is not reversible; 3) Particle concentration: the dilution of a stock containing 5 X 10(11) particles/ml decrease rate of aggregate formation until all aggregation is inhibited; 4) Temperature: the degree of aggregation in the 25 to 37 degrees C range is constant but decreases when the temperature falls below 20 degrees, at +4 C there is no aggregation. The aggregation reaction presents a positive deltaH of 17.9 Kcal/mol and a deltaG of --1.32 Kcal/mol.

Adenoviruses, Human↗
PubMed1979

[The role of anaerobe adhesion in the colonization of the vaginal mucosa].

Some our previous research works on bacterial adhesion to vaginal cells in the different phases of the menstruum showed that adhesion changes depending on changing environmental conditions. We therefore considered interesting to extend our investigations to anaerobic flora, in the light of recent observations intended to attribute an important role to anaerobic flora in the pathogenesis of vaginitis. The results obtained so far indicate that the maximum adhesion capability is found in the middle of the menstruum. The very low adhesion of bacteria belonging to the Leptothrix genus remains substantially unaltered throughout the menstruum. Low adhesion is also found in sporogenic bacteria, whereas the coccoid ones have a stronger adhesion, particularly about the middle of the menstruum. With lower pH values adhesion of the anaerobic flora is enhanced, whereas in the final phase of the menstruum, with higher pH values, adhesion is reduced. Competition tests evidence a stronger adhesion of coccoid as compared to bacillar types.

Adult↗
PubMed1978

[Changes of the intestinal mucosa-bacterial flora ecosystem in rats fed various diets].

A study has been made of the distribution of bacterial flora in the gastro-enteric tract of rats fed on glycidic, protein and lipidic diets and compared with that found in rats given a standard diet. The flora of the gastro-enteric tract was noted in a fraction adhering to the epithelial cells of the mucous membrane and in a fraction present in the contents of the gastro-enteric tract. Changes resulting from the differences in diet are made particularly at the expense of the adhering flora. In groups fed on a glycidic diet there is a clear prevalence of enterococci, enterobacteria, lactobacilli, peptostreptococci and yeasts. In rats fed on a protein diet the quantity and variability fo the flora are less and clostridia predominate. Where rats are given a lipidic diet there is a prevalence of enterobacteria, lactobacilli and peptostreptococci. An extensive and diversified colonization is noted as a further consequence of differences in diet. The results obtained are discussed in relation to certain pathological intestinal conditions and to results reported elsewhere in the literature.

Animals↗
PubMed1978

Cellular response in Salmonella typhimurium-infected mice: evaluation of Salmonella receptors of B lymphocytes.

The cellular response in the course of experimental infection with Salmonella typhimurium was studied in mice. T cells were detected by the presence of theta-antigen, B cells by the binding of fluorescent immunoglobulins, and cells with receptors by labeled Salmonella binding. Lymphocytes were from spleen and lymph nodes. Results have been divided into three groups: group A, including mice with slight symptomatology; group B, including those with serious infection symptomatology; and group C, including mice that died in the course of the experiment. In spleen and lymph nodes of group A mice, an increase in the percentage of T and B lymphocytes was observed. This increase reached a peak 10 days after experimental infection. In lymph nodes, the B-cell percentage was equal to the percentage of T cells, whereas in spleen lymphocytes the B-cell percentage was higher. In spleens of group B mice we observed the same response as in mice of group A, whereas in lymph nodes there was a low response of T and B lymphocytes. In group C mice, there was no significant response of T and B lymphocytes in either spleen or lymph nodes. In B lymphocytes prepared from spleens of surviving mice, a small number of Salmonella receptors was detected: 200 bacterial cells per 10(9) lymphocytes.

Animals↗
PubMed1977

[Changes in the vaginal mucosal bacterial flora ecosystem during the menstrual cycle in women].

It was shown that bacteria of mucosae of higher organisms, mostly have specific receptors for chemical complementary structures of cell surface. On the other hand it is known already that vaginal flora changes during ovulation and afterwards, some infections begin and reveal during some periods of the ovulatory cycle. Therefore, it was studied the adherence of saprophytic and pathogenic bacteria to vaginal cell in different phases of the ovulatory cycle. It was shown that, during the cycle, the bacterial adherence changes because of environment modifications, caused by secretion under hormonal control.

Adult↗
PubMed1975

Membrane damage and incorporation of Escherichia coli components into Bdellovibrio bacteriovorus.

Cytoplasmic membrane of E. coli is degraded within 20 min following infection with Bdellovibrio. 50% of cellular 42-K is lost during the first 10 min. The cytoplasmic membrane, 20 min after infection, centrifugated on a sucrose gradient produces a wide band containing the main enzyme activities (succinic dehydrogenase and lactic dehydrogenase) bound to the membrane. The incorporation into Bdellovibrio of labelled host cell constituents during intracellular growth has been studied at successive intervals during the development cycle in diluted nutrient broth (about 3 hrs). The cells were broken in a Sorvall-Ribi cell fractionator and the Bdellovibrios separated by centrifugation on sucrose gradient. Polysaccharides, proteins and lipids of Bdellovibrio derive from the utilization of components of the host cells and not from the utilization of the components present in the medium. The incorporation of precursors into polysaccharides and proteins shows the same exponential pattern.

Acetates↗