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Biomedical subjects

G Chelazzi

Publications and source records attributed to G Chelazzi.

At least 19 recordsLinked to original sources
PubMed2005

Heavy metals accumulation in two syntopic sandhopper species: Talitrus saltator (Montagu) and Talorchestia ugolinii Bellan Santini and Ruffo.

We assessed the capacity for heavy metals accumulation in Talorchestia ugolinii by standard methods of heavy metals analysis. To compare the bioaccumulation in syntopic sandhopper species, we collected samples of T. ugolinii and Talitrus saltator living on the same and on different beaches in Corsica. There was a marked difference in the zonal distribution of the two species along the sea-land axis of the beach: T. ugolinii was distributed nearer the water line than T. saltator. The bioaccumulation capacity of T. ugolinii only partly matched that of the Mediterranean T. saltator: while Hg, Zn, Cu, and Cd were accumulated by both species, Al and Fe were accumulated by T. saltator but not by T. ugolinii. Pb was accumulated only by T. ugolinii, while Cr did not seem to be accumulated by either species. The bioaccumulation in sympatric T. saltator and T. ugolinii specimens collected on the same beach reflected the general trend of the two species on the Tyrrhenian and Corsican coasts, respectively. Moreover, six of the eight heavy metals considered (Hg, Pb, Zn, Fe, Al, Cu) were present in higher quantities in T. ugolinii than in T. saltator, independently of whether the trace elements were accumulated by the two species. Thus, there are some differences between T. ugolinii and T. saltator, even when the two species live in the same locality. These differences involve their zonation within the damp belt of sand, the bioaccumulation of some heavy metals (Al, Pb, Fe), and the quantity of each heavy metal in the body, independent of the bioaccumulation capacity.

Amphipoda↗
PubMed2004

Different cardiac response to copper in limpets from metal polluted and clean shores of Hong Kong.

The gastropod limpet, Cellana grata, is common on moderately exposed to exposed Hong Kong rocky shores. On the basis of the existing literature on trace metal contamination in Hong Kong, four sites were identified, representative of highly polluted (Aberdeen and Lei Yue Mun) and clean (Cape d'Aguilar and Clear Water Bay) conditions. Limpets from the two polluted sites showed similar, but significantly higher body concentrations of copper than limpets from the two clean sites, which were also similar. Non-invasive measurements of cardiac activity of limpets from the four sites showed between site differences in baseline heart rates under standard seawater, irrespective of pollution level. When acutely exposed to water borne copper (2 h, 0.5+/-0.06 SD ppm), however, limpets from clean sites showed a significantly higher increase in inter-beating time (bradycardia) than those from polluted sites. These results highlight the potential use of cardiac activity to assess the exposure of natural populations of limpets to trace metal pollution.

Animals↗
PubMed2004

Mediterranean Talitrus saltator (Crustacea, Amphipoda) as a biomonitor of heavy metals contamination.

The use of sandhoppers and beachfleas as biomonitors of heavy metals contamination is relatively recent. Using adult individuals of Talitrus saltator from nine localities on the northern Mediterranean Sea, we studied the concentrations of eight trace elements: Al, Cd, Cr, Fe, Hg, Pb, Cu, Zn, both in the substratum and in the individuals. We also carried out a preliminary investigation of the correspondence between the sandhoppers' genetic variability and heavy metal contamination at the sampling sites. T. saltator accumulated Cd, Cu, Zn and Hg (at higher concentrations than in the sand) and also Al and Fe (at lower concentrations than in the sand). It seems that Mediterranean sandhoppers do not accumulate Pb and Cr. An intraspecific comparison between northern European (Baltic) and Mediterranean populations of T. saltator was made. Finally, we observed a tendency to a positive correlation between the sandhoppers' genetic variability and heavy metals contamination.

Amphipoda↗
PubMed2001

Variations in cardiac activity following acute exposure to copper in three co-occurring but differently zoned Mediterranean limpets.

The cardiac activity of three limpets (Patella rustica, P. caerulea and P. aspera), having a different vertical zonation on the Mediterranean rocky shores, was monitored using a non-invasive technique, during 6 h exposure to copper solutions (0.1 and 0.5 ppm), and after return to copper-free conditions. At 0.1 ppm no significant variation of heart rate was observed in the three species with respect to control conditions, while after 3 h at 0.5 ppm a consistent bradycardia was evident in P. caerulea and P. aspera, but not in P. rustica. After 6 h at 0.5 ppm most of the specimens of the three species were acardic but still reactive to mechanical stimulation. Tests on the resumption of cardiac activity after 6 h exposure to 0.5 ppm showed that even after a prolonged cessation of cardiac activity, limpets quickly resumed heartbeating once returned to clean seawater. However, recovery of heart-beating was faster in the mid- and high-shore species (P. caerulea and P. rustica, respectively) than in the lower-shore P. aspera. Moreover, the cardiac pattern upon recovery was definitely bradycardic in P. aspera, while the other two species showed a significant overshooting in heartbeating rate. Measurement of body burdens of copper showed that P. rustica and P. caerulea were faster in removing the excess of copper than the lower-shore P. aspera. In conclusion, this study showed that taxonomically close and syntopic species having a different zonal distribution exhibit different cardiac responses to water-borne copper and stresses the importance of comparative studies on physiological responses of organisms to metal pollution.

Animals↗
PubMed2001

Metabolic responses of the limpet Patella caerulea (L.) to anoxia and dehydration.

This study examined the metabolic responses of the limpet Patella caerulea (L.) to anoxia and dehydration, attempting to tease apart the effect of these two stressful conditions, which are often not clearly distinguished in experiments. Specimens were exposed to: (a) oxygen-free sea water; (b) oxygen-saturated water (controls); (c) low-humidity air (55% RH); and (d) high-humidity air (100% RH). For each of the treatments, we took samples of five specimens after 6 and 18 h of exposure to the experimental conditions and determined the concentrations in the foot muscle of succinate, acetate, propionate, aspartate and alanine. Exposure to anoxia caused an increase in the levels of succinate (6 and 18 h) and acetate and propionate (18 h) with respect to control specimens. Anoxia also induced a decrease of aspartate and an increase of alanine after both 6 and 18 h. Exposure to both moist and dry air generally had negligible effects on the organic acid levels. Aspartate content increased after 18 h of exposure to moist air. Alanine levels also increased with respect to control values after exposure to air, with dry air having the more pronounced effect. In conclusion, the results of this study suggest that one should be cautious when inferring anaerobic conditions from the simple exposure of intertidal species to air, without strict control of the experimental conditions and actual respiration rates.

Acetates↗
PubMed2000

Estimating the energetic cost of fighting in shore crabs by noninvasive monitoring of heartbeat rate.

After establishing shore crabs, Carcinus maenas, individually in separate aquaria, we used a noninvasive infrared phototransducer to monitor their heartbeat rate continously before, during and after fights with intruder crabs. We confirmed that heartbeat rate is a reliable indicator of oxygen consumption and then used it to estimate indirectly the energetic cost of fights differing in duration and intensity, and its dependence on prior residence and relative size of opponent. Prior residence in aquaria significantly increased the probability that crabs would initiate fights against intruders. The majority of fights were resolved by aggressive contacts, display being used extensively only against smaller intruders. Fights between evenly sized opponents and between residents and larger intruders involved almost continuous aggression, whereas fights with smaller intruders involved several shorter bouts of aggression. Fight duration was weakly correlated with the relative size of opponents. Heartbeat rate, measured only in residents, was elevated above resting levels throughout fights, hence energy expenditure during fighting increased linearly with fight duration. Contrary to expectation, heartbeat rate was not significantly influenced by relative size of the opponent or by the intensity of aggression. After fighting, heartbeat rate usually returned to resting levels within 30-60 min, recovery taking longer in fights against larger intruders, when the fight was always lost. We propose that prolonged elevation of heartbeat rate in residents that had lost to larger intruders represented a state of alertness, adaptive against impending risks of resource loss or injury. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Effect of experience on predatory behaviour of dogwhelks.

We used an acoustic transducer to monitor the radular activity of dogwhelks, Nucella lapillus, drilling mussels, Mytilus edulis, in the laboratory and we examined the effect of dietary experience on prey-handling behaviour. For the first time, phases of inspection, penetration and ingestion could be distinguished directly, and consequently the prey-handling process analysed in detail. Dogwhelks with different field-based experience of mussels showed different handling behaviour. Those collected from a mussel-dominated shore more readily adopted the faster method of penetrating between the slightly gaping valves, instead of the slower method of drilling through the shell. Those collected from a barnacle-dominated shore took significantly longer to attack the mussel and then were unable to switch from drilling to penetrating through the gape between valves. Experience of specific prey in the field, by reducing handling time, could promote fitness by reducing exposure to environmental hazards. Laboratory attempts to train dogwhelks from the barnacle-dominated shore to use the gape penetration method failed, suggesting that functional constraints, such as injection of a relaxant when penetrating through the gape and/or genetically controlled behavioural traits, could limit the ability to learn handling skills. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Cardiac and behavioural responses of mussels to risk of predation by dogwhelks.

We used noninvasive, infrared phototransducers to record continuously the heartbeat of common mussels, Mytilus edulis, experiencing successive phases of interaction with the predatory gastropod Nucella lapillus, from initial threat to attack and consumption. Coupling physiological monitoring with behavioural analysis allowed us to investigate in detail the responses of mussels to predation threat. Compared to values of normal feeding activity, heart rate increased significantly when mussels were in the presence of effluent from dogwhelks. When attacked by dogwhelks, mussels increased their heart rate further, together with the rate of valve gaping. Considering the heart rate as a reliable estimator of respiratory function, these cardiac responses might be a mechanism to compensate for increased energy demand in order to cope with predation hazard. If so, the theoretical importance of trading off energy balance against risk of predation is supported by our results. Cardiac and behavioural responses varied throughout the attack according to the penetration method adopted by dogwhelks. When mussels were attacked through a drilled hole, heart rate tended to increase and periods of cardiac pausing appeared close to the point of death. In contrast, mussels attacked by penetration between the valves showed decreasing heart rate throughout the attack, together with relatively earlier cessation of valve gaping and appearance of cardiac pausing. These differences clearly support the hypothesis that dogwhelks penetrating between the valves are able to induce muscular paralysis of prey by injecting toxins. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

[Adult-onset Still's disease. Report of 5 cases].

The authors report 5 cases of Still's disease in adults whose symptoms were mainly characterised by high fever, transient exanthema, polyarthralgia and/or polyarthritis, lymphoadenomegaly, splenomegaly and neutrophil leukocytosis. Assays for leukocytosis were positive, as were those for inflammatory markers and serum ferritin was also high in all 3 patients in which it assayed. On the contrary, serum ferritin latex test, Waaler-Rose reaction and all other tests commonly used to diagnose long-term fevers were all negative. All the subjects examined recovered after prolonged steroid therapy. Only one patient reported severe sequelae in the hip joints and subsequently underwent bilateral hip replacement surgery.

Female↗
PubMed1991

Occlusion of the carotid artery as presenting symptom of acute promyelocytic leukemia.

In a 44-year-old female acute promyelocytic leukemia (APL) presented with abrupt onset of right hemiplegia and aphasia due to occlusion of the left carotid artery at bifurcatio. There was laboratory evidence of disseminated intravascular coagulation (DIC). Thrombotic complications are unusual in APL, even in cases with evidence of DIC. This report aims at underlying the important implication of a correct timely diagnosis in young patients presenting with stroke.

Adult↗
PubMed1990

Total serum IgE levels in children with pertussis.

Total serum IgE levels were evaluated in 20 children with pertussis. Increased levels of serum IgE were observed in the group of children between the ages of 3 and 12 years, while normal levels of serum IgE were detected in the groups of children between birth and 24 months old and between 13 and 24 months old. A further and significant increment of serum IgE levels was also found after 10 days of hospitalization.

Age Factors↗
PubMed1990

Plasma fibronectin concentrations in patients with human immunodeficiency virus infection.

Plasma fibronectin (PFN) concentrations were assessed in 21 patients with AIDS, in seven with AIDS-related complex (ARC), in 17 asymptomatic seropositive patients, and in 36 age and sex matched healthy control subjects. A single radial immunodiffusion technique was used to determine PFN concentration. A significant decrease in PFN concentrations was observed in patients with ARC and AIDS (especially in those patients with Pneumocystis carinii pneumonitis). On the other hand, normal PFN concentrations were observed in asymptomatic seropositive patients. The determination of PFN concentration in patients with AIDS and ARC may contribute to the diagnosis of such patients.

AIDS-Related Complex↗
PubMed1990

[Monoclonal gammopathy of uncertain significance in rheumatic disease].

Among 358 patients with rheumatic diseases, the incidence of monoclonal gammopathy of undetermined significance (MGUS) as detected by immunofixation was 4.4% (11 of 248 patients) in rheumatoid arthritis (RA), 3% (1 of 32 patients) in systemic lupus erythematosus (SLE), 6% (3 of 49 patients) in Sjögren's syndrome (SS) and 3% (1 of 29 patients) in progressive systemic sclerosis (PSS). Solid tumor was present in 4 (36%) of the 11 RA-MGUS patients. In these cases the monoclonal component could be related to a paraneoplastic syndrome rather than to rheumatic diseases. The association of rheumatic diseases, MGUS, solid tumor and immunological disorders are discussed.

Adult↗
PubMed1989

[Primary malignant non-Hodgkin's lymphoma of the stomach. Case series contribution].

Fourteen cases of primary gastric non-Hodgkin malignant lymphoma have been classified according to the "Working Formulation for Clinical Usage" and according to the Kiel classification. They have been staged according to the Ann Arbor staging system modified by Musshoff and according to the Manchester staging system modified by Rao. They have been also arranged in the Friedman's macroscopic types. Clinical features, radiologic and endoscopic findings, performed surgical operations, histologic reports and prognostic factors are reported and discussed. The patients, after surgery, have been treated with radiotherapy and/or polychemotherapy, according to the suggested therapeutic pattern. The follow-up has evidenced a better prognosis than gastric carcinoma. The importance of the preoperative diagnosis is emphasized. This is often difficult to obtain, but it permits a better surgical treatment and especially the right intraoperative staging.

Adult↗
PubMed1987

Peripheral blood lymphocyte subpopulations after splenectomy for trauma.

Absolute and percent numbers of peripheral blood lymphocyte (PBL) subpopulations were evaluated using monoclonal antibodies in 20 subjects splenectomised for trauma. A significant increase was observed in the absolute counts of total PBL, B, null and Leu 7+ cells and in the percent counts of null and Leu 7+ lymphocytes. The percent numbers of OKT11+, OKT4+ and OKT8+ lymphocytes were significantly reduced, but the OKT4+/OKT8+ ratio was not statistically different from normal controls. The increase in B and killer/natural killer cells may provide a compensatory mechanism responsible for surveillance against infections and tumors in splenectomised patients, despite the numerous humoral and cellular abnormalities they commonly display.

Adolescent↗