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Biomedical subjects

G Cavallo

Publications and source records attributed to G Cavallo.

At least 19 recordsLinked to original sources

Demonstration of the formation of hydroxyl radicals in acute myocardial infarction in man using salicylate as probe.

Dihydroxybenzoic acid (DHBA) derivatives of acetylsalicylic acid (ASA) are formed in vivo by the action of the hydroxyl radical (OH.). In order to evaluate the possible formation of OH(.) in acute myocardial infarction (AMI) in man, 9 consecutive patients with a first episode of AMI (8 males, 1 female, mean age 50.3 years), treated with rt-PA, and 8 healthy volunteers (7 males, 1 female, mean age 29.8 years) were studied. All subjects received 100 mg ASA p.o. daily; venous blood samples were taken 30 min after the first dose (time 0) and then at 3-, 6-, 12-, 24- and 48 h and 5 days. Serum was analyzed by HPLC and electrochemical detection for 2,3- and 2,5-DHBA contents. 2,3-DHBA was present in all subjects with AMI and undetectable in healthy volunteers at all time points studied. Serum levels of 2,5-DHBA did not show statistically significant differences between AMI patients and healthy volunteers. These data support the hypothesis that hydroxyl radicals are formed during AMI in man.

Aspirin

Effects of interferon alpha on murine cytomegalovirus replication.

The present study examined the protective effect of IFN-alpha against mouse cytomegalovirus (MCMV) infection in embryo fibroblasts (MEF) of genetically resistant (C3H/HeJ) and susceptible (C57BL/6) mouse strains. At a M.O.I. of 1 IFN-alpha was protective in C3H/HeJ-MEF but not in C57BL/6-MEF. Dot-blot analysis during MCMV replication in C3H/HeJ-MEF showed that IFN-alpha pretreatment reduced the steady state level of immediate early and late mRNAs but partially reduced early gene expression.

Animals

Effect of synthetic polynucleotides on the growth of transplantable tumours in BALB/c mice.

The effect of BALB/c mice pretreatment with tumour cells (a mammary adenocarcinoma, ADK-1t and an IgA secreting plasmocytoma, MOPC-315) adsorbed with poly I:C, poly I and poly C is examined. Only mice pretreated with cells of both tumours adsorbed with poly I:C and poly C proved to be extensively protected against challenge by homologous untreated tumour cells, whereas this was not so in the case of poly I. A possible explanation of this phenomenon is discussed.

Animals

Kinetics of antibody response in unprimed recipients after transfer of immune lymphocytes.

Spleen cells from mice immunized with SRBC were transferred, at various times after immunization, to non-irradiated and lethally irradiated syngeneic recipients. The PFC kinetics and anti-SRBC antibody titres were followed in various groups of mice. Similar results were obtained both in non-irradiated and lethally irradiated recipients, showing that after the transfer: a) PFC proliferation was blocked, b) PFC blocking was unrelated to their maturation stage, c) resting PFC were still able to synthesize antibodies, d) blocking activity was radio-resistant.

Animals

Involvement of a surface concanavalin A-binding glycoprotein in the adhesion of Trichomonas vaginalis to substrates.

Treatment of Trichomonas vaginalis with EDTA removes their ability to adhere to glass surfaces and changes their affinity to Concanavalin A (ConA) by a different distribution of their surface structures. Filtrates of the EDTA-treated Trichomonas passed through affinity chromatography columns (ConA bound to Sepharose 4B) separate into 2 fractions, one fraction was bound to the ConA-Sepharose beads, the other was not. The Con A - bound fraction appears to be a glycoprotein which restores in a specific way the ability of the EDTA-treated protozoa to adhere to glass.

Cell Adhesion

The soluble antigens of Rickettsia prowazeki, R. typhi and R. canada. Investigation of their interrelationship by various serological methods.

The purpose of this research is the isolation of an eventual species-specific fraction from the "soluble antigen" of Rickettsiae. The "soluble antigen" of R. prowazeki (Breinl strain), R. typhi (Wilmington strain) and R. canada were purified at 25% saturation with ammonium sulphate (PSA). Corresponding antisera were produced in rabbits. The serological methods used were the complement fixation, the micro-agglutination, the precipitation method in capillary tubes and the immuno-diffusion method carried out with complete and previously cross-absorbed antisera. Furthermore, the PSA were subjected to immuno-electrophoretic and disc electrophoretic fractionation. The PSA of R. prowazeki was found to contain at least 4 group-specific fractions. A species-specific component could be demonstrated with certainty only with the precipitation method in capillary tubes carried out with previously cross-absorbed antisera. The PSA of R. typhi contains 5 fractions of which 4 are group-specific and one is species-specific. This result was confirmed by all methods. The PSA of R. canada: the maximum of 3 components could be detected with the help of immuno-electrophoretic fractionation. A fourth antigenic determinant was made apparent by the presence of corresponding antibodies in the anti-R. canada PSA only.

Antigens, Bacterial

The effect of pre-treatment of syngeneic mice with tumour cells cultured in vitro on the induction of a transplantable tumour.

The pre-treatment with in vitro cultured mammary adenocarcinoma (ADK-1t) cells strongly protects syngeneic Balb/c mice against the challenge with the same non-cultured tumour cells. If the cultured cells were detached with sodium versenate, 50-60% protection was given, whereas if trypsin was used only 20-30% protection was achieved. That in vitro culture considerably reduces the oncogenic potential of ADK-1t cells was shown by the fact that very many more cultured than non-cultured cells were required to induce tumours.

Adenocarcinoma

Enhancement of tumour growth by pretreatment with tumoral cells adsorbed by poly i:c deae-dextran complex in syngeneic mice.

Pretreatment of balb/c mice with ADK-1t cells adsorbed with Poly I:C DEAE- dx complex was found to enhance tumour growth as measured after challenge with non adsorbed ADK-1t cells. This results contrasts strongly with the increased tumour resistance previously observed when Poly I:C alone was used for adsorption. Some reasons are suggested for this striking difference.

Animals

[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

The murine IFN-gamma receptor does not transduce the activation signal to a murine promoter in human cells.

MuIFN-gamma receptor cDNA has been stably transfected in the human WISH cell line. A stable transfectant, denominated WISH-C2, expressed 46;000 receptors/cell whose affinity was similar to that observed on murine cells (Kd = 2.6 x 10(-9) M). When WISH-C2 cells were treated with Hu- or MuIFN-gamma, antiviral and antiproliferative activities were observed with HuIFN-gamma only. These findings suggest that other species-specific components associated to the binding site are required for the signal transduction. To overcome the complexity of measuring biological functions that very likely involve more than one regulatory and structural gene, we set up for the first time a system where a reporter gene driven by a murine promoter was used to directly evaluate the interaction of MuIFN-gamma receptor with an inducible promoter through the missing transducer factor.

Animals

Cancer and environment.

The attention of scientists has been directed mostly to analyze the influence of the environment on tumor induction. However, the external environment can also enhance the reactivity of the host organism towards tumors, by activating several immune mechanisms. Moreover, the host organism is the first "foreign" environment with which tumor cells come into contact in a dynamic way, characterized by a continuous evolution.

Animals

The parasite-host relationship: an immunological game.

In the present paper we have analyzed the host-parasite relationship and the influence of parasite infections on the immune system. In all cases aberrations in either humoral or cellular immune response are observed. Moreover the constant feature of parasite infections is the stimulation of the reticular endothelial system that induce an increased aspecific resistance toward various antigens.

Animals

Medicine and man.

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Philosophy, Medical