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Biomedical subjects

A Carminati

Publications and source records attributed to A Carminati.

6 recordsLinked to original sources
PubMed2006

Evaluation of the health of free-ranging greater rheas (Rhea americana) in Argentina.

The health of 22 free-ranging adult rheas (Rhea americana) examined and sampled during a translocation/reintroduction project and six juvenile rheas kept in semicaptivity was investigated, and details of their haematology and plasma biochemistry are presented. Serological testing for antibodies to infectious agents was negative for infectious laryngotracheitis, avian adenovirus, avian influenza, avian reovirus, infectious bursal disease, infectious bronchitis virus, paramyxovirus types 1, 2, and 3, fowlpox and Salmonella Pullorum. Antibodies to Chlamydophila species were found in 25 of 27 of the birds, and 22 of 25 had antibodies to Aspergillus species. Ova of gastrointestinal nematodes of the genus Capillaria were identified, and the anoplocephalid cestode Monoecocestus cf rheiphilus was identified in R americana for the first time.

Animals↗
PubMed1989

Pathways and kinetics of aqueous decomposition and carbamoylating activity of new anticancer nitroimidazole-linked 2-chloroethylnitrosoureas.

The products of decomposition in anaerobic aqueous solution at pH 7.1 and 37 degrees were determined for two series of novel anticancer agents incorporating both nitroimidazole and 2-chloroethylnitrosourea moieties (NI-CENUs) and examples of which exhibit preferential hypoxic toxicity against HeLa-MR cells. The decomposition products identified were vinyl chloride, acetaldehyde, 2-chloroethanol, ethylene glycol and imidazole-bearing compounds of the type including oxazolidinone, ethylamine or urea moieties. Series A NI-CENUs, which contain a 2-hydroxypropyl unit, gave rise to the oxazolidinone intramolecularly compared with the series B agents which gave rise to the imidazole-ethylamine and ureas. The half-lives of the B series agents were comparable with those of 1,3-bis(2-chloroethyl)nitrosourea (BCNU), 2-cyclohexyl-1-(2-chloroethyl)-1-nitrosourea (CCNU) and streptozotocin. The carbamoylation activity of the series B agents was approximately ten times that of series A compounds. This latter property may be related to the greater potency of series B than series A NI-CENUs against Mer+ HeLa-S3 cells via inhibition of relevant repair enzymes.

Antineoplastic Agents↗
PubMed1989

Chemosensitization at reduced nitroimidazole concentrations by mixed-function compounds combining 2-nitroimidazole and chloroethylnitrosourea.

A mixed-function compound (I-278) combining 2-nitroimidazole and chloroethylnitrosourea has been shown to be greater than 2-fold more toxic to hypoxic HeLa-MR cells than to cells similarly exposed under aerobic conditions, consistent with chemosensitization of nitrosourea toxicity by the 2-nitroimidazole Misonidazole (MISO). However, in the case of I-278, the enhancement resulted from micromolar concentrations of 2-nitroimidazole as opposed to the millimolar quantities required for a similar enhancement by MISO. These experiments provide evidence (1) that the enhanced hypoxic toxicity of I-278 is not attributable to additional, independent hypoxic cell killing by the nitroimidazole group and (2) that the interaction between the two functions under hypoxic conditions results in increased crosslink formation typical of chemosensitization. The data strongly suggest that the chemosensitizing efficiency of nitroimidazoles can be dramatically improved by covalent linkage to a chloroethylating species.

Cell Survival↗
PubMed1988

Aerobic and hypoxic toxicity of a new class of mixed-function drugs associating nitroimidazoles and chloroethylnitrosourea in nitrosourea-sensitive (Mer-) and -resistant (Mer+) human tumor cells.

The cytotoxicity of two series (A and B) of novel mixed-function compounds (NI-CENU) combining nitroimidazole (NI) and chloroethylnitrosourea (CENU) functions were examined in Mer- HeLa-MR and Mer+ HeLa-S3 cells. Series A compounds differed from those in Series B by having a hydroxypropyl as opposed to an ethyl group linking the imidazole ring and the nitrosoureido function. Four analogues, including the imidazole and the 2-, 4-, and 5-NO2 derivatives, were evaluated in each series. Cells were exposed to the various compounds for 4 h under aerobic and hypoxic conditions, and toxicity was assessed by clonogenic assay. Corresponding analogues in Series A and B were equally toxic to HeLa-MR cells. Preferential hypoxic toxicity was observed only with the 2-NO2 derivative in either series (I-278, Series A; I-282, Series B). For either compound a dose enhancement factor of 2.4 was observed for hypoxic exposures. The Mer+ HeLa-S3 cells were considerably more resistant to the NI-CENU than were their HeLa-MR counterparts. In further contrast to the HeLa-MR data, the Series B compounds were consistently more effective against the HeLa-S3 cells than were their corresponding Series A analogues. The enhanced effectiveness of the Series B compounds in HeLa-S3 cells may be related to the fact that these compounds express carbamoylating activity whereas Series A compounds lack this property. Again only I-278 and I-282 were preferentially toxic to hypoxic cells; however, the aerobic/hypoxic differential was dramatically reduced (dose enhancement factor = 1.3) as compared to that observed with the HeLa-MR cells. The enhanced hypoxic toxicity of the 2-NO2 NI-CENUs was not due to direct hypoxic toxicity of the nitro moiety but presumably is the result of enhancement of CENU toxicity (i.e., chemosensitization). The data suggest that much lower concentrations of NI may be required to observe chemosensitization when the NI and chemotherapeutic agent are administered as a single mixed-function compound.

Aerobiosis↗
PubMed1988

On a new class of mixed-function drugs associating nitroimidazoles and CENU: the NICE-NU.

Two series of (2-chloroethyl) nitrosoureas (NICE-NU) bearing a nitroimidazole group have been synthesized for anti-tumor evaluation with the aim of chemopotentiation of their biological activity. Their anti-tumor activity against L1210 in vivo in mice is excellent especially for the series A derivatives where a hydroxy function provides assistance to decomposition. However, the activity of NICE-NU against B16 melanoma is lower.

Animals↗