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Biomedical subjects

C Locatelli

Publications and source records attributed to C Locatelli.

At least 19 recordsLinked to original sources
PubMed2006

Lipid lowering activity of hydrosoluble chitosan and association with Aloe vera L. and Brassica olearaceae L.

The lipid lowering activity of chitosan associated with Aloe vera L. or hydrosoluble chitosan with Brassica olearaceae L. has been studied in rats. In this study, rats were submitted to different treatments with hydrosoluble chitosan alone (4% diet), hydrosoluble chitosan associated with Aloe vera L. or hydrosoluble chitosan with Brassica olearaceae L. (1:4, 4% diet) for 35 days, to identify the formula with the highest hypolipaemic potential. The results showed that all treatments reduced blood lipid levels but that hydrosoluble chitosan associated with Brassica olearaceae L. proved most efficient, because it decreased the levels of total cholesterol, LDL-cholesterol, VLDL-cholesterol and triglycerides in blood serum. The overall results suggest that the hydrosoluble chitosan/Brassica olearaceae L. association is a therapeutic alternative for hyperlipidaemia, and in this way may contribute to the prevention of atherogenic processes.

Aloe↗
PubMed2001

Sulfur speciation in mercury-contaminated sediments of a coastal lagoon: the role of elemental sulfur.

Chemical equilibrium studies have predicted that elemental sulfur (S0) could play a crucial role in mercury mobility in salt marsh sediments. This prompted us to consider the occurrence of S0 in conjunction with the degree of contamination in sediments of a coastal wetland (Pialassa Baiona, Italy) impacted by inputs of mercury derived from past industrial activity. The distribution of S0, total Hg, soluble sulfates and acid-soluble sulfides was studied in five sediment cores collected in two ponds of the lagoon. Sulfides, sulfates and S0 exhibited vertical profiles typical of salt marsh systems, with concentrations declining with depth. Mercury enrichment (2-23 mg kg-1) was detected at the surface strata where the highest concentrations of sulfides and S0 were found (up to 1.70 and 0.9 g kg-1, respectively). The effect of elevated levels of sulfides and elemental sulfur on the fate of mercury in the lagoon is discussed.

Biological Availability↗
PubMed2001

Carbon monoxide cardiotoxicity.

Cardiac dysfunction including arrhythmias and myocardial ischemia have often been reported in carbon monoxide poisoning; scattered punctiform hemorrhages throughout the heart have been documented in autopsy samples. An appropriate diagnostic approach is crucial to assess carbon monoxide cardiac damage. This evaluation may be confounded by several factors, including the absence of overt symptoms and of specific ischemic changes in the electrocardiogram. In experimental studies, laboratory animals can develop cardiac changes similar to those seen in humans and therefore proved to be useful models to study the effects and the mechanisms of cardiac damage due to carbon monoxide. These investigations, as well as others performed in vitro, provide support for a direct action of carbon monoxide on the heart, in addition to systemic hypoxia produced by carboxyhemoglobin formation. This review focuses on the diagnostic aspects of carbon monoxide cardiotoxicity. Experimental results obtained in animals and in vitro models are also discussed.

Animals↗
PubMed2001

Cardiac damage in pediatric carbon monoxide poisoning.

BACKGROUND: Cardiovascular disorders including myocardial ischemia and heart failure have been described in both laboratory animals and humans following carbon monoxide poisoning. Carbon monoxide cardiotoxicity may be clinically occult and often remains undiagnosed because of the lack of overt symptoms and specific ischemic changes in the electrocardiogram. Routine myocardial necrosis markers have low diagnostic efficiency, particularly in patients with concomitant skeletal muscle necrosis or multiple organ failure complicating carbon monoxide poisoning. Carbon monoxide-induced cardiotoxicity has been investigated rarely in children. CASE REPORT: This paper describes carbon monoxide poisoning in a 12-year-old child who suffered from occult cardiac damage despite mild symptoms and low carboxy hemoglobin concentrations. Myocardial and mitral valve dysfunctions were observed, suggesting an ischemia-like syndrome. Cardiac damage was completely reversible within 1 month. CONCLUSION: This case report supports that a prolonged carbon monoxide exposure can cause cardiac damage in children even in the absence of specific symptoms, cerebral failure and high carboxyhemoglobin concentrations.

Carbon Monoxide Poisoning↗
PubMed2001

Time-dependent oxidative stress caused by benznidazole.

Benznidazole (BZN) is a nitroimidazole derivative which has a notable trypanocide activity, and it is the only drug used in Brazil and Argentina for the treatment of Chagas' disease. The drug in current use is thought to act, at least in part, by inducing oxidative stress within the parasite. Imidazolic compounds are involved in the production of reactive oxygen species (ROS). In order to evaluate the effect of BZN on ROS production and on the antioxidant status of the host, male rats were treated for different periods of time (2, 4, 6, 10 and 30 days) with 40 mg BZN/kg body weight. After treatment, biomarkers of oxidative stress such as the activities of catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST) and glutathione reductase (GR), and also thiobarbituric acid reactive species (TBARS), reduced glutathione (GSH), total glutathione (TG) and oxidized glutathione (GSSG) concentrations, were measured in crude hepatic homogenates. Our results revealed that BZN is able to cause tissue damage as shown by increased TBARS content, inhibition of some antioxidants and induction of other antioxidants in a concentration- and time-dependent manner. The tissue damage measured as TBARS increased up to the 10th day of treatment. GST activity was inhibited during the BZN treatment. On the other hand, CAT and GR showed similar increased activities at the beginning, followed by decreased activities at the end of the treatment. After 30 days of treatment, GR activity remained low while CAT activity was high, compared to controls. The SOD activities remained unchanged throughout the experimental period. GSH showed lower values at the beginning of BZN treatment but the hepatic concentrations were enhanced at the end of the experimental period. Total glutathione showed a similar profile, and oxidized glutathione showed higher values in rats treated with BZN. In conclusion, these results indicate that, at therapeutic doses, BZN treatment elicits an oxidative stress in rat hepatocytes.

Animals↗
PubMed2000

Mild ciguatera poisoning: Case reports with neurophysiological evaluations.

Ciguatera poisoning causes mainly gastrointestinal and neurological effects of variable severity. However, symptoms of peripheral neuropathy with paresthesias and paradoxical disturbance of thermal sensation are the hallmark. Electrophysiological studies are often normal, except in severe cases. We report four people who developed mild ciguatera poisoning after barracuda ingestion. Electrophysiological studies documented normocalcemic latent tetany. These findings are consistent with ciguatoxin's mechanism of toxicity, which involves inactivation of voltage-gated Na(+) channels and eventually increases nerve membrane excitability.

Adult↗
PubMed2000

Proposal of new analytical procedures for heavy metal determinations in mussels, clams and fishes.

New analytical procedures and sample mineralizations for the determination of copper, lead, cadmium, zinc and mercury in matrices such as mussels, clams and fishes are proposed. An H2SO4-HNO3 acidic mixture was used for the determination of copper, lead, cadmium and zinc. In the case of mercury, the sample digestion was performed using a concentrated suprapure H2SO4-K2Cr2O7 mixture and the results compared with those from other conventional methods. Differential pulse anodic stripping voltammetry (DPASV) was employed for simultaneously determining copper, lead, cadmium and zinc, while the mercury determination was carried out by cold vapour atomic absorption spectrometry (CV-AAS) with reduction with SnCl2, using an innovative method for sample dissolution. The analytical quality control procedures have been verified on three reference standard materials: Oyster Tissue NIST 1566, Mussel Tissue BCR-CRM 278 and Cod Muscle BCR-CRM 422. For all the elements in the certified matrices, the precision, expressed as relative standard deviation (Sr), and the accuracy, expressed as relative error (e), were of the order of 3-5%, while the detection limits were in the range 0.010-0.080 microgram/g.

Animals↗
PubMed1997

Occupational asthma and rhinitis caused by 1,2-benzisothiazolin-3-one in a chemical worker.

We report a case of occupational asthma and rhinitis caused by inhalation of 1,2-benzisothiazolin-3-one, an additive used as a microbicidal in detergent production, in a 26-year-old man employed in a chemical factory producing detergents. The subject's task consisted of pouring raw materials into the recipient of a machine which mixed the substances. Two months after the beginning of this job the patient complained of rhinitis and asthma at the workplace. The specific challenge test with 1,2-benzisothiazolin-3-one, one of the raw materials to which the subject was exposed, provoked an immediate prolonged asthmatic response and nasal symptoms, whereas exposure to other agents (e.g., alpha-amylase, alcalase or bezalkonium chloride) to which the patient was also exposed at work did not. To our knowledge this is the first case of occupational asthma and rhinitis caused by this compound.

Adult↗
PubMed1997

A new fast and standardless method for direct determination of metals associated with particulate matter in air: avoiding errors in the determination of Pb in an urban environment.

We describe a new method and the relevant instrumentation necessary for its implementation in the analysis of metals associated with particulate matter in air. The procedure can be divided into two steps: in the first step the sample is accumulated in a device through electrostatic precipitation whose center is a graphite tube; in the second step the graphite tube itself is used as an atomization device for the determination of the metals present in the sample through the electrothermal atomic absorption technique. The method is simple, fast, accurate, and inexpensive. Moreover, if the experimental conditions are well chosen, there is no need for calibration, which is very convenient in the case of samples such as particulate matter in the air. The elements that can be determined with the present apparatus are Hg, Cd, Tl, Ag, Mg, and Mn. These are highly or medium volatile because the materials used cannot reach very high temperatures for long periods. The experiments are confined to air, but other gases, in which a corona discharge is possible, would give the same results. With the method proposed, it was possible to show that the official method for Pb determination in the urban environment of Bologna presents a negative systematic error of about 25%.

Lead↗
PubMed1996

Surface mechanomyogram reflects muscle fibres twitches summation.

The aim of this work is to define the pattern of summation of the muscle fibre twitches in the surface mechanomyogram (MMG) generation process. For this purpose, two groups of muscle fibres of the extensor digitorum communis (EDC) were stimulated using needle electrodes. To these two artificial (because made by different muscle fibre types) motor units (MU1 and MU2), we administered: (a) separate stimulations: 3 and 9 Hz (MU1), 8 and 20 Hz (MU2) for 5 s; (b) simultaneous stimulation: 3 Hz (MU1) + 8 Hz (MU2); 9 Hz (MU1) + 20 Hz (MU2) for 5 s. The mechanomyograms, recorded during separate stimulation of MU1 and MU2, were linearly summated for the generation of a mechanomyographic signal to be compared with the one detected during (b) stimulation procedure. The bispectrum and the bicoherence of the generated MMG (MMGg) and of the MMG recorded during simultaneous (MMGs) stimulation were calculated for the detection of the quadratic non-linearity in the system responses. It was found that the MMGg and MMGs presented difference in the bispectrum and bicoherence index only when the 9-20 Hz stimulation pair was considered In conclusion, our data indicate that the MMG derives from the summation of the active muscle fibres twitches and that the latter is linear only for very low firing rates. This is to be carefully considered when studies on MMG modelling will be undertaken.

Electric Stimulation↗
PubMed1996

[Smoking and pregnancy: search for a correlation between cotininemia and Doppler findings].

OBJECTIVE: To search for a possible correlation between an effective marker of smoking and uterine and placental resistance during pregnancy. STUDY DESIGN: A prospective study was conducted at the Intercommunal Hospital Center of Montreuil, France: 81 healthy pregnant women underwent uterine and placental Doppler and cotidin blood assay, the best current test for smoking. RESULTS: This study shows a significative increase of utero-placental vascular resistances according with increased cotidine levels. CONCLUSIONS: The previously observed association between smoking and perinatal events most likely involves vascular resistance of uterus and placenta.

Adult↗
PubMed1994

Nutrition and alcohol neurotoxicity.

Neurological complications of alcoholism such as Wernicke-Korsakoff syndrome and polyneuropathy often originate from interactive factors involving direct nervous system toxicity of ethanol and nutrient deficiencies associated to heavy drinking. Not all patients are equally susceptible to these disorders and a genetic predisposition to thiamine deficiency has been described in subjects with Wernicke's encephalopathy. At moderate alcohol dosages, nutrient abnormalities may be marginal, inducing no obvious manifestations until other neurotoxic agents are absorbed. Examples are presented illustrating the interaction of ethanol and styrene on brain glutathione metabolism in rats, and cases of methanol poisoning in alcoholics. In these patients, ethanol-induced folate deficiency can potentiate visual toxicity of methanol due to impairment of the folate-dependent pathway involved in formate detoxication. The notion that nutritional deficiencies and ethanol toxicity may act synergistically in the nervous system outlines the importance of adequate nutritional strategies in the treatment of alcoholism and also indicates that methodological flaws may result during experimental studies from failure to control for nutritional variables.

Animals↗
PubMed1993

Interactions of pre-operative erythromycin administration with general anaesthesia.

Previous reports have demonstrated a gastric emptying effect of erythromycin due to a motilin-like mechanism. We studied 50 patients, scheduled for daycase laparoscopy, randomly assigned to one of two groups: Group P patients received 30 min before induction of anaesthesia, in a double-blind manner an infusion of 250 ml dextrose 5% while patients in Group E (n = 25) received 500 mg of erythromycin diluted in 250 ml dextrose 5%. An orogastric tube was inserted to measure both gastric pH using a pHmeter and residual gastric volume (RGV) using the phenol red dilutional technique. Six patients were excluded for surgical reasons. More patients in Group P (6/22) than in Group E (0/22) had RGV > 25 ml and more patients in Group P (17/22) presented with a gastric pH < 2.5 than in Group E (5/22), P < 0.05. Since coma and respiratory depression have been reported recently after midazolam and alfentanil administration in patients having received erythromycin, recovery conditions were assessed and were found to be comparable between groups. In conclusion, the administration of iv erythromycin before outpatient laparoscopy decreased residual gastric volume and increased gastric pH without affecting recovery from general anaesthesia.

Adult↗
PubMed1990

Digestion method for the determination of mercury in vegetable matrices by cold vapour atomic absorption spectrometry.

A simple and rapid wet-digestion procedure is described for the determination of total mercury in botanical samples by cold vapour atomic absorption spectrometry. The method is based on the oxidising properties of potassium dichromate in dilute sulphuric acid and was tested on two National Institute of Standards and Technology Standard Reference Materials. The mass of the samples taken for analysis was about 0.5 g in all instances, corresponding to an amount of mercury of the order of 0.075-0.040 micrograms depending on the material. The results were compared with those obtained using the Association of Official Analytical Chemists official digestion technique, which involves the use of nitric and sulphuric acids, and a second technique based on the action of nitric and perchloric acids. The proposed method provided better accuracy and showed good precision. Its ability to achieve the decomposition of two organomercurials for full mercury recovery was verified.

Mercury↗