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Biomedical subjects

D Savoia

Publications and source records attributed to D Savoia.

At least 55 records · Page 3Linked to original sources
PubMed1985

Production of monoclonal antibodies against the carbohydrate of group A streptococci.

Mouse hybridomas were isolated by fusing P3.X63.Ag8-653 myeloma cells with spleen cells from BDF1 mice repeatedly immunized with Streptococcus pyogenes type 3 ATCC 12384. Two out of 480 growing cultures secreted antibodies against the bacterial strain used as immunogen, as evaluated by an ELISA assay. After cloning the most representative continuously growing clone, 1-181, the binding specificity of these monoclonal antibodies was determined using either Streptococci with carbohydrate of different group or different bacteria strains. Binding properties suggest that the 1.181 monoclonal antibodies specifically recognize the carbohydrate moiety of Streptococci group A.

Animals↗
PubMed1985

Staphylococcus aureus: characters associated with its pathogenicity and sensitivity to antibiotics.

A hundred staphylococcus strains recently isolated from hospital specimens of various kinds were first divided into two groups: mannitol-positive (90 strains) and mannitol-negative (10 strains). Their ability to produce protein A was then correlated with the presence of other metabolic and enzymatic characters typical of S.aureus. The results showed that satisfactory identification of S. aureus in clinical practice requires assessment of other more species-specific characters in addition to the mannitol fermentation, though this is useful as a preliminary screening measure. Evaluation of protein A production would seem as good or even better than evaluation of coagulase for this purpose. It was also found that the strains examined displayed an increased resistance to methicillin, particularly the part of non-aureus (mainly S.epidermidis) strains. Nearly all strains displayed resistance to the penicillins through the production of penicillinase.

Coagulase↗
PubMed1983

Adhesion of Proteus species to various cell types.

Pathogenic and saprophytic Proteus strains from the urine of patients with urinary tract infections and healthy adults respectively were evaluated with regard to their ability to adhere in vitro to homologous cells (uroepithelial cells from urinary sediment and cultured WISH cells) and heterologous cells (RK-13 and MDCK cells). The effect on attachment of pretreating bacteria with subinhibitory concentrations of piperacillin and sagamicin was also determined for one sensitive and one resistant strain. Fifty percent of the pathogenic Proteus strains demonstrated good adherence to human urinary epithelial cells, whereas saprophytic strains did not adhere. There was a lower rate of attachment to culture cells. Piperacillin and sagamicin in subinhibitory concentrations caused a decrease in the attachment of the sensitive Proteus strain.

Adhesiveness↗
PubMed1983

Streptococcal receptors for human immunoglobulins.

Six streptococcus strains with a high affinity for human serum Ig were examined under various experimental conditions to correlate their structures with specific IgG and IgA receptors. Treatment at 80 degrees C for 5 min appeared to have no effect on their ability to bind IgG and/or IgA, while long maintenance in culture determined a dissimilar partial loss of IgG and IgA binding ability. Proteolytic enzymes and hot HCl reduced the ability of these strains, especially those in group A, to absorb both IgG and IgA. It would seem that the protein most involved in this type of bond is the T protein.

Humans↗
PubMed1983

Pseudomonas aeruginosa beta-lactamases.

Forty recently isolated hospital strains of Pseudomonas aeruginosa were assayed to determine the part played by the production of beta-lactamase in their resistance to beta-lactamic antibiotics, together with the relative importance of constitutive and inducible enzymes in such resistance in the case of carbenicillin (CB). 62.5% were CB-resistant. In 56% of cases, this resistance was due to the production of a class Vd constitutive enzyme, whereas it was ascribable to intrinsic resistance in the other 44%.

Anti-Bacterial Agents↗
PubMedDate not supplied

Rapid diagnosis of malaria by use of fluorescent probes.

Malaria diagnosis relies on observation of parasites in blood smears and the Giemsa-stained thick blood smear (G-TS) is the reference test. Diagnosis by G-TS in low-density infections requires long periods of observation and experienced microscopists. Examination of Giemsa-stained thin smears enables more reliable differentiation of species but may miss low-grade infections. Fluorescent stains may offer an alternative technique. We compared the Giemsa technique with 4,6-diamidine-2-phenilindolo-propidium iodide (DAPI-PI) stainings in order to evaluate the time required for diagnosis. A Plasmodium falciparum-infected blood specimen was diluted to obtain concentrations ranging from 6192 to 24 parasites/microliters (p/microliter), and thin and thick smears were stained with the two methods. The DAPI-PI proved useful: parasites were easily recognized and their morphology was preserved in thin and thick smears. The method allowed more rapid evaluation of thin smears as compared with Giemsa staining and enabled recognition of parasites in case of low-level parasitemias. The DAPI-PI staining technique may acquire an important role in malaria diagnosis, especially in nonendemic countries where technicians are not experienced with G-TS; in developing countries, it could be used in epidemiologic surveys of populations with low-density parasitemias, for which it enables a fast examination of smears and possibly the identification of parasite species.

Azure Stains↗
PubMedDate not supplied

Immunological investigation of malaria and new perspectives in paleopathological studies.

We applied a paleoimmunological investigation, using an immunoenzymatic assay revealing trophozoite derived Plasmodium falciparum histidine rich protein-2 antigen (PfHRP-2). The investigation was carried out on skin, muscle and bone samples. We examined predynastic egyptian mummies (3200 B.C.) from Gebelen, belonging to the Marro's Collection of the Anthropological and Ethnographic Museum of Turin, to assay the presence of malaria. The results obtained suggest an incidence of malaria of about 40% in the mummies of Gebelen group. Data are compatible with other observations effected on populations living in similar ecological conditions of malarial areas.

Animals↗
PubMedDate not supplied

[In vitro antibacterial activity of a halogenated derivative of D-alanine].

The "in vitro" effect of beta-chloro-D-alanine, a drug that inhibits cell-wall synthesis, was studied. We used some strains of microorganisms, mainly Gram-negative and resistant to antibiotics with the same mechanism of action. MIC and MBC values obtained show a poor efficacy of this drug. Therefore we studied the association of beta-chloro-D-alanine with ampicillin and fosfomycin. The evaluation of the results, determined by means of a graphic and a mathematical method, shows a good synergistic effect with both associations. Synergism is more marked with ampicillin.

Alanine↗
PubMedDate not supplied

[A new technic for determination of antibiotics in the renal parenchyma].

The determination of antibiotics in the renal tissue is of real value only if the blood and the residue urine are removed from the kidney. The Authors report a new technique dealing with the washing of the organ "in situ" by means of an artery-vein perfusion succeeded by the sucking of the residue urine from the ureter. The experiments were carried on male albino rats with the following antibiotics: indanylcarbenicillin, tobramycin, fosfomycin and cefazolin.

Animals↗
PubMedDate not supplied

[Synergism of dicloxacillin and broad-spectrum penicillins].

On the basis of the proved protective activity showed by isoxazolyl penicillins on other antibiotics, a comparative study about the action of dicloxacillin over four penicillins with a broad spectrum was carried on. Either the experiments "in vitro" (antibacterial activity, growth dynamics, determination of beta-lactamase inactivation) then those "in vivo" have proved a real protection. A comparative study on different associations was also performed.

Bacteria↗
PubMedDate not supplied

[The antibacterial action of the amoxicillin-flucloxacillin combination].

A mixture of amoxycillin, semisynthetic penicillin beta-lactamase susceptible, and flucloxacillin, an isoxazolylpenicillin, in combination 1:1 was tested. This mixture shows real synergic effect "in vitro" on beta-lactamase producing Gram-positive and Gramnegative bacteria and an additive effect on the other microrganisms. Good results have been obtained "in vivo" and a protective effect of flucloxacillin on enzymatic degradation of amoxycillin by beta-lactamase was found.

Amoxicillin↗