Biomedical subjects

D Savoia

Publications and source records attributed to D Savoia.

At least 73 records · Page 4Linked to original sources

PubMedDate not supplied

[Enzyme activity in Leishmania].

Some enzymes produced by the protozoon Leishmania can have an important role in the intraphagocytic survival of the parasites. The production of hydrolytic enzymes by promastigotes belonging to two Leishmania sp. (major and infantum) and maintained in different experimental conditions was evaluated. The proteolytic activity was moderate, while superior was the production of acid phosphatase in L. infantum. An increase of the trypsin-like activity was observed after incubation of protozoa for 24 h at 37 degrees C, while a mouse injection did not changed the enzymatic activity of L. major.

Animals↗

PubMedDate not supplied

[Effect of high temperature on promastigotes of 2 species of Leishmania].

A morphological and chemical transformation of the protozoon Leishmania results during the shift from sand fly vector to mammalian host. This is due to the increase in temperature from about 26 degrees to about 35 degrees C. We evaluated the modifications induced by 37 degrees C on stationary phase promastigotes of two different Leishmania species (L. major and L. infantum). L. infantum changed to amastigote-like forms in a greater and quicker way than L. major; this fact could relate with the more elevated spreading capacity of this species in the human body.

Animals↗

PubMedDate not supplied

[Leishmaniasis: effect of factors present in serum].

An important role in the interaction between protozoan parasite Leishmania and host is determined by serum factors. The activation of complement can have resistance-promoting effects (due to the lysis of parasite) or disease-promoting effect (due to the opsonization of Leishmania). Also lymphokines can determine resolution or progression of the infection. Particularly, gamma-interferon "in vitro" increases the killing of the parasite and "in vivo" cures cutaneous leishmaniasis.

Animals↗

PubMedDate not supplied

[Host-parasite interactions: mechanisms for recognition and attack].

Host-parasite interactions were studied by several researchers in these last years, both to better understand some parasite diseases and to identify new targets and strategies for the control of these infections. In this paper some of the most important recognition's mechanisms demonstrated between specific parasite structures and host cell receptors are reported, and particularly those concerning protozoa Leishmania, Plasmodium, Entamoeba, Giardia and Pneumocystis.

Adaptation, Physiological↗

PubMedDate not supplied

[Microscopic diagnosis of Pneumocystis carinii. Comparison of various staining technics].

The toluidine blue 0 and methenamine-silver nitrate staining techniques allowed a good microscopic distinction of Pneumocystis carinii cysts in lung autoptic impression smears. Poor results we observed with methylene blue and modified Gram techniques. With Giemsa's stain the intracystic bodies are shown, however the microscopic examination requires experience and patience.

Azure Stains↗

PubMedDate not supplied

[Surface characteristics of Streptococci: evaluation technics].

We examined the surface characteristics of 41 strains of Streptococci by using the salt aggregation technique (SAT). While group B, C, D and G Streptococci showed a clearly hydrophilic surface, 57.5% of group A strains revealed so hydrophobic characters as to be autoaggregating. Either the hydrophobicity or the autoaggregation of these Streptococci decreased after subsequent culture passages. A comparison has been done for 5 strains by the hydrophobic interaction chromatography (HIC) demonstrating a good correlation between the two techniques. As the only presence of M protein did not seem to condition the surface characteristics, however treatments with different proteolytic enzymes modify greatly the bacterial surface suggesting the involvement of various protein structures.

Bacterial Adhesion↗

PubMedDate not supplied

[Changes in surface characteristics of group A streptococci].

We examined the surface characteristics of four group A Streptococcus strains in log or stationary phase of growth by using the techniques of salt aggregation and of adhesion to n-hexadecane. By means of the former technique a greater correlation was observed between surface hydrophobicity and production of M protein (above all in stationary phase of bacteria). Using the latter one, we noted differences depending on the growth phase, but not related to M protein. The pretreatment of bacteria with subCMI of clindamycin decreases their hydrophobicity, particularly in M+ strains and in stationary phase of growth. Less variations of surface were observed in M- strains and after treatment with subCMI of imipenem.

Antigens, Bacterial↗

PubMedDate not supplied

[In vitro comparative activity of norfloxacin in the comparison of pathogenic bacteria of the urinary tract].

In this study 411 bacterial isolates from clinical urinary tract infections against some quinolones, azthreonam and trimethoprim + sulfamethoxazole combination were tested. Bactericidal kinetics of norfloxacin , cinoxacin and azthreonam against E. coli ATCC 25922 was determined. Both MICs values and bactericidal activities have shown that fluoroquinolones are more active against all Gram-positive and Gram-negative bacteria tested than the other drugs.

4-Quinolones↗

PubMedDate not supplied

[Cytotoxic activity of Trichomonas vaginalis supernatants toward cellular monolayers].

In the present paper we analyzed the cytopathogenic activity of 3 recently isolated strains of T. vaginalis on cellular monolayers of human and animal origin. Proliferation of protozoon was accompanied by the progressive and total disintegration of cellular monolayers. Supernatants obtained by incubating cellular monolayers and Trichomonas or Trichomonas alone showed a similar cytopathic effect. A less lytic activity was shown with supernatants containing fetal calf serum. Cytopathogenicity started at 9th hour and was completed at 24th hour. Both this activity and adherence to cells may contribute to the pathogenicity mechanism of T. vaginalis.

Animals↗

PubMedDate not supplied

[Human dirofilariasis: observation of an ocular form].

Several cases of human dirofilariasis has been recently reported in literature; the localization of parasite was especially in subcutaneous tissues. A case of ocular dirofilariasis observed in a woman living in a country near Turin is described. The worm was an immature female with characters in agreement with the description of Dirofilaria conjunctivae (Addario, 1885), nematode responsible of an high percentage of canine filariasis.

Aged↗

PubMedDate not supplied

[Effect of some steroid hormones on the growth of Trichomonas vaginalis].

Studies were conducted to determine the effect of some steroid hormones, particularly sex hormones, on the growth of Trichomonas vaginalis "in vitro". 17 alpha-estradiol and 17 beta-estradiol were stimulatory for parasite growth, progesterone and testosterone were inhibiting, whereas cholesterol and ergosterol lacked such effects. Changes on the growth of T. vaginalis were observed in the first 20 hours of incubation with specific hormonal concentrations. These observations confirm the influence of sex hormones on the pathogenesis of trichomoniasis.

Cholesterol↗

PubMedDate not supplied

[Identification of Pneumocystis carinii in a patient dying of AIDS].

We compared two different techniques in the preparation of slides for the demonstration of Pneumocystis carinii in lung tissue of a patient died for AIDS. The impressions were prepared by imprinting the autopsy tissue surfaces on glass slides, while the concentrates were prepared by a partial homogenization and subsequent centrifugation of the pulmonary tissue. After staining, the number of protozoa microscopically observed resulted similar with both techniques; moreover using impression smears P. carinii were more easily visible.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

[Comparative activity of norfloxacin and other chemotherapeutic agents on the adhesion of bacteria of the uro-vaginal tract to uroepithelial cells].

A number of bacterial strains (Escherichia coli, Proteus mirabilis and streptococci), obtained from patients with urinary infections, or from vaginal tampons, were assayed in order to evaluate their ability to adhere to uroepithelial cells. We employed, at a comparative purpose, two different methods to eliminate unattached bacteria: the centrifugation technique and the filtration technique. The effect of the pretreatment with subinhibitory concentrations of three chemotherapeutics widely employed in the urological practice (norfloxacin, pipemidic acid and co-trimoxazole) was determined on the strains which demonstrated a good rate of attachment. Growth in the presence of any of the three drugs decreased the adhesive properties of the microorganisms, reducing both the haemagglutination and the yeast aggregation titers of Gram-negative bacteria as well as their adhesiveness. Norfloxacin proved to be the most effective drug in affecting the pathogenicity characteristics of the assayed strains in comparison with the other two chemotherapeutics tested, even if they were also moderately able to inhibit the adhesiveness of the same strains.

Anti-Bacterial Agents↗

PubMedDate not supplied