Biomedical subjects

E Burdino

Publications and source records attributed to E Burdino.

At least 19 recordsLinked to original sources

PubMed2006

Development and utilization of a quantitative polymerase chain reaction assay to evaluate human polyomavirus JC DNA load.

AIM: Quantitative polymerase chain reaction (PCR) analysis to evaluate virus load in comparison with the patient's base-line virus levels would be an optimal diagnostic approach to monitoring human polyomavirus infections and to investigate their possible involvement in the onset of nephropathy in this patient group. Studies on the correlation between viral burden and renal disease have pointed to the incidence of JC virus (JCV) related progressive multifocal leukoencephalopathy (PML) occurring in renal and haematopoietic stem cell transplant recipients. METHODS: We developed a reliable internally-controlled quantitative PCR assay to measure JCV-DNA in fluid samples of urine, serum and cerebrospinal fluid (CSF) by densitometric analysis of the amplification products. The assay was also used to evaluate the JCV load in CFS samples from patients with suspected demyelinating syndrome and in urine and serum samples from healthy subjects and renal transplant recipients. RESULTS: All CSF samples from the 51 patients with suspected demyelinating syndrome tested JCV-DNA negative: none of them had a diagnosed PML. Analysis of the prevalence of JCV-viruria and JCV-viraemia confirmed our previous data. JCV-viruria was detected in 17% of renal transplant recipients and 26.6% of healthy controls; JCV-viraemia was found in 3.4% of transplant patients and 0% in controls. Noteworthy was a lower prevalence of JCV-viraemia in the 116 (3.4%) renal transplant patients than the prevalence previously reported for the 51 (11.8%) patients with suspected demyelinating syndrome. The mean viral load of viruria was much higher in the healthy controls than in the transplant recipients [104020 DNA copies/mL (DS+/-62284) vs 4136 DNA copies/mL (DS+/-77371)]. CONCLUSIONS: The quantitative PCR assay developed in our lab offers in 2 h time a reliable true quantification of viral DNA by densitometric analysis of the amplification product. To check for the possible presence of potential Taq polymerase inhibitors an internal control (the homemade pJCV-C plasmid) is used. The relation between polyomavirus infections and their possible involvement in post-transplant pathologies need further investigation. It would be useful to monitor the JCV-DNA load in urine and serum from more renal transplant recipients, including patients with nephropathy or active graft rejection over a longer period of time.

Base Sequence↗

PubMed1997

Zinc ethylene-bis-dithiocarbamate (Zineb)-mediated inhibition of monooxygenases and lipid peroxidation in bovine liver microsomes.

Hepatic bovine microsomes were incubated with Zineb concentrations ranging from 2.5 mM to 2.5 microM. Only the higher concentrations of the fungicide (2.5 and 0.25 mM) elicited a sharp decline in cytochrome P450, cytochrome b5 and total sulphydryl groups content as well as in the activities of NADPH cytochrome c reductase, aminopyrine N-demethylase and aniline 4-hydroxylase. The loss of cytochrome P450 was matched by a concomitant increase in the amount of cytochrome P420, which represents a catalytically inactive form of cytochrome P450. The same concentrations of the fungicide, either alone or in the presence of NADPH 1 mM, failed to increase the amount of thiobarbituric reactive substances with respect to control incubations, thereby excluding the possibility of lipid peroxidation as a contributing factor in the loss of cytochrome P450 and in the inhibition of cytochrome P450-mediated metabolism. It is concluded that Zineb can depress monooxygenase activity in bovine hepatic microsomes mainly through the denaturation of cytochrome P450 and the impaired transfer of reducing equivalents to the complex cytochrome P450-substrate. These mechanisms might also account for the inhibition in lipid peroxidation brought about by the fungicide.

Aminopyrine N-Demethylase↗

PubMed1996

Gender differences in ethanol oxidation and cytochrome P4502E1 content and functions in hepatic microsomes from alcohol-preferring and non-preferring rats.

1. We have studied the hepatic microsomal metabolism of ethanol (MEOS), CYP2E1 expression and catalytic activity, and the response to phenobarbital (PB) induction or CCl4 challenge in rats of either sex genetically selected for their preference (P) or aversion (NP) for ethanol. 2. In P versus NP females, the amount of both total cytochrome P450 and P450 binding to metyrapone was lower, whereas the activities of MEOS, aniline 4-hydroxylase (4-AOH), and 4-nitrophenol hydroxylase (PNP-OH) as well as the level of immunodetectable CYP2E1 content were consistently higher. By contrast, no substantial differences were observed between P and NP males. 3. Despite an apparent down-regulation of CYP2E1 expression occurring in all rats as a result of PB induction, P females maintained higher 2E1 levels and showed enhanced MEOS, 4-AOH and PNP-OH activities with respect to NP females. No such changes were detected in the male counterparts. 4. No sex-related differences in CCl4-mediated inhibition of monooxygenase or MEOS activities were evident between P and NP animals. 5. These results indicate that, in females only, the behavioural trait of ethanol preference is apparently associated not only with higher constitutive levels of CYP2E1 and rate of microsomal metabolism of ethanol but also with altered susceptibility to PB induction.

Alcohol Drinking↗

PubMed1995

Effects of the subchronic administration of zinc ethylene-bis-dithiocarbamate (zineb) to rabbits.

The effects of subchronic administration (90 d) of zineb were studied in male New Zealand White rabbits. Rabbits were allotted to 3 groups of 8 animals each and offered diets containing 0, 0.3 or 0.6% zineb. A marked decline in weight gain, hemoglobin concentration, hematocrit, and erythrocyte and leucocyte counts occurred at the highest zineb dosage. There was a dose-related depression in circulating thyroid hormones, whereas serum lipid concentration, particularly that of cholesterol and triglycerides, increased. Hepatic lipid concentration was considerably reduced in rabbits exposed to 0.6% zineb. Neither serum testosterone nor the activities of selected testicular enzymes showed changes suggestive of testicular involvement. Pathological changes were in agreement with biochemical findings; there was a marked dose-related enlargement of the thyroid showing histological colloid struma. An increase in relative weight and moderate glycogenosis were detected in liver, whereas no lesions occurred in testes. It was concluded that thyroid and liver are the main targets for zineb toxicity in the rabbit. Unlike the results from previous studies conducted on other food-producing species, repeated exposure of rabbits to zineb failed to cause testicular damage. This might be related to the inability of zineb to significantly accumulate in the testes.

Analysis of Variance↗

PubMed1994

Amelioration of diabetes and cataract by Na3VO4 plus U-83836E in streptozotocin treated rats.

Experimental work in our laboratory has confirmed the protective activity of vanadium compounds on hyperglycemia and glycosuria in streptozotocin (STZ) diabetes. Furthermore, diabetic cataract has also been partially prevented. Nevertheless, the combination of a natural antioxidant, vitamin E, with Na3 VO4 has not further enhanced this ameliorating effect. Our experimental approach has been an attempt to block the prooxidant activity of both STZ and vanadate, with the purpose of eliciting the best possible antidiabetic protection. More recently, a lipid soluble synthetic antioxidant U-78517F, a 2-methylaminochroman, has been reported to have a significant protective effect against brain injury and ischemia. This compound inhibits the iron-dependent lipid peroxidation 100 times more effectively than vitamin E. This investigation has introduced a combination of the vanadium compound plus the aforesaid lazaroid, as its (-) enantiomer, U-83836E, in order to improve the insufficient protection when vitamin E was used. For twelve weeks, male Wistar rats, rendered diabetic with STZ, were administered Na3VO4 in drinking water along with the lazaroid carried by the food. Four, eight and twelve weeks after the beginning of the protective treatment, fluid and food intake, diuresis and excreted feces, glycosuria and proteinuria were determined on biological samples obtained in metabolic cages; body weight and glycemia were also recorded. At weeks 6 and 12 of the treatment, the opaqueness of the eye lenses was controlled and registered. At the end of the experiment, circulating glycosylated hemoglobin (HbA1c), fructosamine, N-acetyl-beta-D-glucosaminidase (NAG), and fluorescent peroxides were evaluated. Within the first month of treatment, protection by the combination paralleled that elicited by vanadate alone. At subsequent steps, U-83836E significantly improved the protective effect of vanadate alone on polydipsia and polyuria, but especially on hyperglycemia and glycosuria. The further ameliorating effect of the lazaroid was also observed on HbA1c and NAG, and, most important, on the cataract. In conclusion, these findings demonstrate that the lazaroid U-83836E succeeds in further protecting the most important symptoms of diabetes treated with vanadate, and that this antioxidant acts effectively even when it is administered orally in food, in a non invasive manner.

Acetylglucosaminidase↗

PubMed1993

Induction of hepatic drug metabolizing enzymes and interaction with carbon tetrachloride in rats after a single oral exposure to atrazine.

A single oral dose (430 mg/kg) of atrazine, a widely employed s-triazine herbicide, was administered to young male rats. There was a significant increase of the in vivo elimination of hexobarbital and a significant induction of the activity of 7-pentoxyresorufin-O-dealkylase, while cytochrome P-450 content and other mixed function oxidase activities remained unaltered. The administration of carbon tetrachloride (CCl4) to atrazine pretreated rats did not substantially augment the impairment of drug metabolizing enzymes brought about by CCl4 alone. Results suggest that atrazine behaves like a relatively weak inducer of phenobarbital-inducible families of cytochrome P-450.

Animals↗

PubMed1991

Lethality, hexobarbital narcosis and behavior in rats exposed to atrazine, bentazon or molinate.

Previous findings from our laboratory suggested a possible interaction of atrazine, bentazon and molinate with other environmental and/or occupational poisons. The aim of this research was to obtain further toxicological information by using phenobarbital-induced rats and to characterize the effects of these herbicides on the hepatic microsomal metabolism of xenobiotics. Acute experiments have shown that the LD50 is augmented by the barbiturate pretreatment when atrazine is used, remains unchanged in the case of bentazon, but is lowered when molinate is given. Recrystallized atrazine, in the absence of the wetting compounds, elicits the same acute toxicity found when animals are challenged with a commercial preparation. No significant sex-related differences have been observed. In long-term treatment with these toxicants, atrazine shortened the hexobarbital narcosis, but no effect was observed after administration of either bentazon or molinate. Further studies on hexobarbital sleeping time demonstrated that females are more susceptible than males to the narcotic effect of this compound. The induction-like effect of atrazine exposure has been confirmed, mainly in young animals. At the end of the sleeping time, the actual serum concentration of hexobarbital is practically the same, and is not related to the length of the sleeping time. The absence of behavioral alterations in the open field tests exclude possible neurological effects of the triazine herbicide. In conclusion, these data demonstrate that atrazine by itself induces the hepatic pharmacometabolic system, while its metabolites result less toxic than the parent compound. On the contrary, metabolic transformations render the toxic effects of bentazon more severe.

Age Factors↗

PubMed1987

Effects of the chronic administration of sodium selenite on rat testes.

Testis structure and functions were monitored in male Wistar rats chronically exposed to various levels of sodium selenite (Na2SeO3) in drinking water (4, 8 or 16 ppm). The most remarkable testicular changes were observed in the 16 ppm group: intertubular oedema, oligospermia, scattered foci of degenerated spermatids were found. In addition, marked changes in several specific enzymes of testicular cells occurred along with a significant reduction of mean-tubular-diameters, mean-tubular-areas and mean-tubular-perimeters. These results clearly demonstrate a testicular involvement during chronic exposure of the rat to selenium.

Animals↗

PubMed1986

A model for monitoring changes in liver function.

An experimental model for monitoring rat liver function during protracted exposure to hepatotoxic agents is proposed. Owing to their invasiveness, the models usually employed are appropriate for studying the mechanism of action of toxic substances, but do not allow the liver situation to be followed over the course of time. The need to sacrifice animals to determine liver triglycerides-one of the key parameters in the progress of toxic damage- reduces the possibility of following such progress in the same animals. This study describes the testing of a model for monitoring three basic parameters of liver injury: cytolysis, steatosis and metabolic deficiency of the liver. CCl4 has been chosen as model-hepatotoxin. Steatosis is determined by evaluating the triglyceride content of small specimens of liver, obtained through open-field biopsies, which appear to be representative of the whole liver. Fatty liver is paralleled by the block in Triton-induced hypertriglyceridaemia. Determination of serum triglycerides derives from a very poorly invasive technique which can be repeated several times. The combination of these tests with the assessment of both the cytolysis (ALT and SDH release into the circulation) and the impairment of the efficiency of liver microsomal enzymes (TMO clearance), seems to offer a reliable experimental procedure in predicting the hepatotoxic effect of xenobiotics.

Animals↗

PubMed1983

Impairment of erythropoiesis in rats exposed to environmental pollutants.

The extent to which halogen compounds interfere with erythropoiesis is still unclear. This paper reports an evaluation of the effect of repeated exposure to carbon tetrachloride (CCl4) in air on red blood cell (RBC) creatine concentration. Creatine is neither synthetised nor metabolised in circulating RBC and decreases over the lifespan of red cells. It can thus be taken as a reliable indicator of mean RBC age, and hence of cell viability and bone marrow efficiency. Following inducement of hemolysis with phenylhydrazine (PHH) to stimulate erythropoiesis, creatine levels rose in the controls. This increase was significantly less in the CCl4-treated animals. It is not yet certain whether this inhibition reflects impaired marrow efficiency, enhanced RBC destruction in the marrow, or block of the release of mature RBC. The fact that such inhibition takes place, however, is of importance as a predictive factor in environmental toxicology, since it appears before changes in other blood parameters or signs of liver toxicity are observed.

Animals↗

PubMed1982

Mechanism of protection against carbon tetrachloride toxicity. I. Prevention of lethal effects by partial surgical hepatectomy.

Both partial surgical hepatectomy and a challenge with a small dose of CCl4 depress the metabolism of xenobiotics in the liver. In fact, hepatocytes become provided with metabolic activity rates which are peculiar of either embryo or newborn rat liver. These experiments have shown that partial surgical hepatectomy prevents rats from death caused by otherwise lethal doses of CCl4. At the same time, sham-operated animals survive to a limited extent after a large dose of the halogen compound. Investigations carried out on the metabolic efficiency of liver microsomes, both in vito and in vivo, clearly demonstrate that the preventive effect against CCl4 depends mainly on the impaired metabolic activity of endoplasmic reticulum.

Aminopyrine N-Demethylase↗

PubMed1982

Mechanism of protection against carbon tetrachloride toxicity. II. Lethality in rats fed a polyunsaturated fatty acid deficient diet.

A PUFA-deficient diet causes deficiency symptoms and alters the fatty acid pattern in liver microsomal lipids. However, CCl4 lethality and sleeping time remain unchanged while the hepatic level of cytochrome P450 is only slightly lowered by the dietary regimen. In accordance, the amplitude of double bond shifting in microsomal lipids is far from being depressed in animals deprived of the peroxidative substrate. In fact, the experimental treatment does not impair intestinal absorption, liver uptake and metabolism of CCl4 given orally. Finally, both in vitro and in vivo peroxidative challenge of arachidonic acid content in hepatic microsomes causes comparable alterations of this parameter, whatever the initial fatty acid pattern following the dietary regimen. These findings provide evidence excluding an influence of the fatty acid composition of the diet on the severity of damages due to halogen-alkane exposure.

Animals↗

PubMed1980