PubMed Health⌕ Search

Biomedical subjects

A Massi

Publications and source records attributed to A Massi.

At least 19 recordsLinked to original sources
PubMed2002

Solid-supported reagents for multi-step organic synthesis: preparation and application.

Since the early days of combinatorial chemistry solid-phase organic synthesis has been the method of choice for the production of large libraries. Solution-phase synthesis is again gaining importance especially for the synthesis of parallel arrays of smaller, focussed libraries containing single compounds with high degrees of purity. In the field of solution-phase library generation, the use of solid-supported reagents, catalysts and scavengers is emerging as a leading strategy, combining the advantages of both solid-phase organic synthesis (e.g. allowing the employment of an excess of reagent without the need for additional purification steps) and solution-phase chemistry (e.g. the ease of monitoring the progress of the reactions by applying LC-MS, TLC or standard NMR techniques). An account of some of the most recent advances in this area of research will be presented.

Combinatorial Chemistry Techniques↗
PubMed1995

Interspecies differences in mixed function oxidase activity in birds: Relationship between feeding habits, detoxication activities and organochlorine accumulation.

The relationship between feeding habits and interspecies differences in the detoxication ability of the mixed function oxidase (MFO) system was investigated in birds. The role of MFO (particularly aldrin epoxidase activity) in the detoxication/bioaccumulation of organochlorines was also investigated. Euriphagic (yellow-legged herring gull (Larus cachinnans), black-headed gull (Larus ridibundus), jackdaw (Corvus monedula), magpie (Pica pica) and stenophagic (cormorant (Phalacrocorax carbo), coot (Fulica atra) and sparrow (Passer italiae)) species were collected in northern and central Italy. The following liver microsomal monooxygenase activities were measured: aldrin epoxidase, ethoxyresorufin dealkylation (EROD), benzyloxyresorufin dealkylation (BROD) and pentoxyresorufin dealkylation (PROD). NADPH-and NADH-cytochrome c reductase (NAD(P)H-CYT-CRED) and NADH-ferricyanide reductase (NADH-FERRIRED) activities were also measured in the liver microsomal fraction. Glutathione concentration (GSH) was measured in the liver cytosolic fraction. As a marker of liver damage gamma-glutamyl transpeptidase (GGTP) activity was assayed in the serum. The residues of organochlorines (HCB, pp'DDTs and PCBs) were determined in muscle samples. Omnivorous species, particularly the yellow-legged herring gull, had the highest aldrin epoxidase activities. In the yellow-legged herring gull the activity was approximately twice as high as in the jackdaw (p < 0.05), black-headed gull (p < 0.05) and coot (p < 0.05). Values five times lower were detected in the specialist fish-eater, the cormorant (p < 0.001). The lowest values of aldrin epoxidase activity were detected in the sparrow. Feeding habits were found to be related to evolutionary interspecies differences in MFO activity. A significant statistical correlation (r = 0.656) was found between the 'omnivore index' and MFO detoxication activity expressed as aldrin epoxidation. Organochlorines, and particularly PCBs, were higher in cormorants and yellow-legged herring gulls from a polluted lagoon than in the other species analysed (black-headed gull p < 0.01; sparrow p < 0.001; jackdaw p < 0.01; coot p < 0.001). Levels of pp'DDE were much higher in the cormorant and sparrow than in the other birds. Knowledge of the different species-specific detoxication abilities was found to be a useful tool for the identification of species potentially at risk in environments with high pollution by chlorinated hydrocarbons, or in general contaminants metabolized by the MFO system.

Journal Article↗
PubMed1992

Serum esterase inhibition in birds: a nondestructive biomarker to assess organophosphorus and carbamate contamination.

With the aim of proposing a nondestructive biomarker for monitoring the toxicological risk to birds of exposure to the organophosphorus insecticide azamethiphos and the carbamate insecticide methomyl, laboratory studies were performed on serum "B" esterases in Japanese quail (Coturnix coturnix japonica). The birds received two single dose treatments of each compound (azamethiphos and methomyl), i.e., 50 mg/kg and 250 mg/kg respectively. In the first treatment, serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) were drastically inhibited in the azamethiphos-treated group, 24 h after the dose. No inhibition was detected for BChE and CbE activities in the methomyl-treated group, 24 h after the dose. In the second treatment, the birds died or were sacrificed 3 h after the dose. Serum BChE and brain acetylcholinesterase (AChE) were strongly inhibited after treatment with both insecticides. Serum CbE, hepatic microsomal CbE and 7-ethoxyresorufin dealkylation activities were also inhibited. A statistically significant correlation between serum BChE and brain AChE was found at lethal and sublethal doses of these xenobiotics. The experimental results indicate that the nondestructive biomarker BChE can give an early qualitative and semi-quantitative warning of the toxic effects of organophosphate and carbamate insecticides in birds.

Animals↗
PubMed1989

An assessment of pollutants in eggs of Audouin's gull (Larus audouinii), a rare species of the Mediterranean sea.

Audouin's gull (Larus audouinii) is a very rare species endemic to the Mediterranean basin. A sub-population of an estimated 130 pairs is breeding in the Tuscan Archipelago, an area heavily polluted by mercury and chlorinated hydrocarbons. Here we present the data from 5 years spent monitoring the contaminant levels in the eggs of this species. Mercury, selenium, polychlorobiphenyls (PCBs) and DDE concentrations are two to five times higher than in similar species, such as the yellow-legged herring gull, nesting in the same area. The annual trends in these contaminant levels are discussed. In view of the endangered status of Audouin's gull, there is a need to observe closely the developing trend of contamination in this species.

Animals↗
PubMed1989

Trace elements and chlorinated hydrocarbons in eggs of Pelecanus crispus, a world endangered bird species nesting at Lake Mikri Prespa, North-western Greece.

Eggs of the Dalmatian pelican, Pelecanus crispus, collected from 1984 to 1986 at Lake Mikri Prespa, north-western Greece, contained residues of trace elements and PCBs at low concentrations, and of DDE at rather high concentrations. DDE is negatively related to eggshell thickness. Eggshell thickness was reduced by 12-20% in comparison with the pre-1947 (before DDT use) eggshell thickness. However, this decrease did not affect the reproductive success of this species. The main fish species eaten by the Dalmatian pelican at Lake Mikri Prespa were analyzed for pollutants. All the fish contained low concentrations of residues. The contribution of the diet while the birds are on the wintering grounds is unknown. Recommendations for a monitoring programme of pollutants in eggs of the Dalmatian pelican, a world-endangered species, are proposed.

Journal Article↗