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Biomedical subjects

L Manzo

Publications and source records attributed to L Manzo.

142 records · Page 8Linked to original sources
PubMedDate not supplied

Determination of S-phenylmercapturic acid by GC-MS and ELISA: a comparison of the two methods.

S-phenylmercapturic acid (PMA) is a specific urinary biomarker of benzene at exposure levels lower than 1 ppm. However, measuring PMA in urine is an expensive task by either GC or HPLC due to the necessity of extensive sample pretreatment. In the present study, a commercial chemiluminescence enzyme-linked immunosorbent assay (ELISA) test for PMA and GC-MS were used for screening urine samples of 60 workers employed in petrochemical settings. The ELISA results were evaluated by comparison with the GC-MS. Overall, the ELISA test proved sensitive (limit of detection=0.1 microg l(-1)), rapid, robust and reliable, affording results in good agreement with the GC-MS (54% of measurements) and no false-negatives. On the other hand, 46% of the ELISA assays were assigned as false-positives (arbitrarily established when ELISA >5 microg l(-1), GC-MS <5 microg l(-1) and a correlation coefficient of 0.687 was calculated between the two methods. It appears that urinary PMA routine biomonitoring on large numbers of samples is carried out in a cost-effective and rapid approach by preliminary screening with the ELISA assay followed by GC-MS confirmation of concentrations exceeding the biological exposure index for PMA.

Acetylcysteine↗
PubMedDate not supplied

Exposure to hydrocarbons and renal disease: an experimental animal model.

The association between hydrocarbon exposure and chronic glomerulonephritis is still a controversial scientific issue. Recent epidemiological evidence suggests a role of exposure to hydrocarbons in the progression of glomerulonephritis towards chronic renal failure. The present experimental study on rats has been designed to assess the possible role of styrene in the progression of adriamycin (ADR) nephrosis, a well known model of renal fibrosis following nephrotic syndrome induced by ADR. Female Sprague-Dawley rats were exposed to styrene, 300 ppm, 6 h/day, 5 days/week for 12 weeks (group 1); treated with ADR, 2 mg/Kg, i.v., twice on day 1 and day 15 of the study (group 2); Additional groups of animals received both the styrene and ADR treatments (group 3) or served as controls (group 4). The urinary excretion of total and single proteins (albumin, Retinol-Binding Protein (RBP), Clara Cell 16 Kd protein (CC16), fibronectin) was measured monthly, whereas histopathology and determinations requiring blood sampling were carried out at the end of the experiment. A progressive increase in total proteinuria, falling in the nephrotic range already by the 6th week was observed in ADR-treated groups. Styrene exposure caused up to a 3- to 5-fold increase as compared to controls. Co-exposure to ADR and styrene also resulted in a proteinuria much greater than that caused by ADR alone. The interactive effect of styrene and ADR was statistically significant for albuminuria and urinary fibronectin. A similar response was observed for glomerular filtration rate at the end of the experiment, styrene-exposed animals showing hyperfiltration as compared to their respective control group. At the end of the experiment, histopathological scoring for interstitial infiltration and fibrosis was also significantly higher in styrene-treated animals as compared to their respective control groups. In ADR-treated rats, low molecular weight proteinuria (l.m.w.p.) was only slightly affected, suggesting minimal tubular dysfunction associated with extensive tubular atrophy. However, styrene-exposed animals showed l.m.w.p. higher than their respective controls. In summary, in this animal model we were able to confirm both styrene-induced microproteinuria, mainly albuminuria and minor increases in l.m.w.p., observed among occupationally exposed workers and the role of hydrocarbon exposure as a factor accelerating the progression of renal disease suggested by epidemiological investigations in patients suffering from chronic renal disease. Whereas in rats exposed to styrene only, microproteinuria was stable over time and minor histopathological changes were noted at the end of the experiment, evidence of a role of solvent exposure in the progression of ADR nephropathy was obtained in terms of both renal dysfunction and interstitial fibrosis. The mechanistic basis of styrene-ADR interaction is unclear. However, experimental evidence is consistent with epidemiological findings suggesting the need to avoid solvent exposure in patients suffering from renal diseases.

Albuminuria↗
PubMedDate not supplied

Creative teams: an experiential activity.

BACKGROUND: Staff development educators in a Department of Education & Development were seeking a creative activity to reinforce the qualities of effective teams. METHOD: Staff development educators developed an experiential activity that provides an opportunity to observe team behaviors by introducing several glitches into a goal-oriented team project. Later, observed team behaviors were explored with the group. RESULTS: The activity allowed participants to practice collaboration, communication, and problem-solving skills while functioning as a team. CONCLUSION: This activity, which is easily adaptable to any audience, creatively integrates the principles of adult learning to provide participants with an opportunity to discuss and practice behaviors necessary for teamwork in the current health care settings.

Adult↗
PubMedDate not supplied

[Occupational poisoning with psychiatric manifestations].

Numerous occupational intoxications (acute, chronic and their sequelae) may affect the central nervous system and result in a wide variety of neuropsychiatric effects, ranging from subtle behavioural disturbances to overt psychosis. Chemicals causing such manifestations include many metals and organometals (Hg, Mn, Pb, Al, Sn), pesticides (organophosphates), compounds utilised in the industrial setting as solvents or intermediates (carbon disulfide, hydrocarbons and their halogenated derivatives), and combustion products (carbon monoxide). Some types of toxic insults may not be reflected in any clinical manifestation. However, this type of damage may render the brain more vulnerable to additional insult or accelerate physiological loss of neurones with ageing. Thus, occupational exposures to chemicals (Al, Pb, organic solvents) might be involved in the causation of neurodegenerative diseases--such as Alzheimer's disease--which are usually labelled as "idiopathic". A careful occupational anamnesis is crucial to diagnose work-related psychiatric manifestations and--consequently--to interrupt the toxic exposure, to start therapy, and to promote insurance compensation.

Aluminum↗
PubMedDate not supplied

Cholinergic contractions induced by GABA-A receptor activation in the guinea-pig ileum are inhibited by alpha-chymotrypsin and potentiated by diazepam.

The influence of alpha-chymotrypsin and diazepam on the phasic (mainly direct) and tonic (indirect, probably substance P-mediated) components of intestinal cholinergic contractions, induced by the GABA-A receptor agonist 3-aminopropane sulphonic acid (3-APS), was investigated in the guinea-pig ileum. alpha-Chymotrypsin, at a concentration (20 U/ml) not affecting submaximal Ach (0.1 microM) contractions, preferentially depressed the tonic component of the 3-APS (30 microM)-induced response. A brief exposure (10 or 60 sec) to diazepam (0.1 microM) potentiated both the phasic and the tonic contractions evoked by low (10, 30 microM) 3-APS concentrations. This potentiation was prevented by bicuculline (30 microM), hyoscine (1 microM) and flumazenil (1, 3 microM). These results provide further support for an involvement of a peptide neurotransmitter on GABA-A receptor-mediated cholinergic response in the ileum. The modulation of this response by diazepam is probably exerted through recognition sites resembling the "central type" benzodiazepine receptors.

Acetylcholine↗
PubMedDate not supplied

Toxicology and health impact of environmental exposure to boron. A review.

The presence of high concentrations of boron in community water supplies has been reported as a localized problem in certain areas of United States, USSR and Italy. In this paper, current information on sources, occurrence, pollution potential and toxicity of environmental boron is reviewed. In animals, chronic low-level boron exposure has been shown to cause reduced growth, cutaneous disorders and suppression of male reproductive system function. The mechanisms underlying these effects and available data on dose-response relationships are discussed in connection with human health hazards possibly associated with continuous low-level absorption of boron compounds.

Adult↗
PubMedDate not supplied

Human toxicology of boron with special reference to boric acid poisoning.

The improper use of boric acid containing antiseptics is still one of the most common causes of toxic accidents in newborns and infants. Health hazards may also arise from inadvertent absorption of insecticides and household products containing borates as well as from occupational accidents related to production and use of boranes. A variety of boronated agents with hypolipidemic, antiinflammatory or anticancer properties have been developed in recent years. Unfortunately, most of these compounds were found to be highly toxic when tested at the required therapeutic dosages in animals. In this paper, recent information on human toxicology of boron is reviewed, with special emphasis on epidemiological and clinical aspects of boric acid poisoning.

Adult↗
PubMedDate not supplied

Alcohol interactions with typical and atypical antidepressants.

Selected parameters of central nervous system function have been examined in rabbits and mice given ethyl alcohol (ET) in combination with antidepressant drugs with different pharmacological profiles. A significant prolongation of the ET-induced loss of righting reflex was observed in mice treated with amitriptyline, 3 mg/kg, or trazodone, 8 mg/kg, injected intraperitoneally. The same drugs failed to cause narcosis when given alone to mice at doses up to 40 (amitriptyline) and 100 (trazodone) mg/kg. Rabbits given single 5 mg/kg IV doses of amitriptyline or trazodone exhibited a synchronous EEG pattern with an increase in spectrum total power that became more pronounced after IV injection of a low dose of ET (0.2 g/kg). The increase in the spectrum total power after ET was significantly greater in rabbits given trazodone than in those given amitriptyline. No significant interactive effects were observed in animals receiving combinations of ET with viloxazine, bupropion or fluvoxamine.

Animals↗
PubMedDate not supplied

[Oncogenes as indicators of occupational exposure to carcinogenic agents].

Oncogenes are a class of genes capable of inducing neoplastic alterations of the cell. Recently, oncogenes have received greater attention in environmental medicine, since they may be useful tools for monitoring individuals exposed to carcinogenic chemicals. Their potential use as biomarkers is supported by studies indicating changes in the expression of growth factors and oncoproteins in chemically induced cancer. These alterations may even take place prior to clinical diagnosis. In addition, availability of new immunoblotting techniques, which allow the detection of oncoproteins and growth factors in easily accessible tissues, such as serum and urine, has provided promising preliminary results in humans. In this paper, mechanisms of oncogene activation and their role in occupational carcinogenesis are briefly discussed. Recent human studies suggesting a link between occupational toxicants and oncogenes, as well as a potential use of oncogenes as biomarkers, are also reported. Finally, advantages and limits of oncogenes over more traditional biomarkers are discussed.

Carcinogens, Environmental↗
PubMedDate not supplied

[Indoor pollution: a report of 2 clinical cases of occult carbon monoxide poisoning].

A large part of the general population is potentially exposed to excessive concentrations of carbon monoxide (CO), both in the domestic and work environment. Beside acute, often fatal poisoning, the possibility of occult intoxication should be considered; this condition can affect people who are often unaware of the existence of a toxic exposure in their homes or work places. We describe two non-smoking patients, husband and wife, 53 and 57 years old, respectively, who suffered cephalea, nausea and neurobehavioural disturbances during a period of approximately one year; these symptoms were reported to improve or disappear on several occasions during the patients' absence from home. Careful anamnesis suggested a protracted exposure to nonlethal concentrations of CO contaminating the patients' bed-chamber from the misfunctioning flue of the heating system. It was not possible to measure carboxyhaemoglobinemia until approximately 24 hours since the last presumptive exposure. The levels found were therefore relatively low (4-5%), yet higher than the reference values for normal non-smoking subjects. Carboxyhaemoglobin concentrations almost returned into the normal range during the period of hospitalization. These two cases exemplify how low level CO exposure may cause aspecific pathological manifestations that are often misdiagnosed or overlooked.

Air Pollution, Indoor↗
PubMedDate not supplied

Biomarkers in environmental medicine: alterations of cell signalling as early indicators of neurotoxicity.

Many environmental and occupational chemicals are known to affect the central and/or peripheral nervous system, causing changes that may result in neurological and psychiatric disorders. Because of the limited accessibility of the mammalian nervous tissue, new strategies are being developed to identify biochemical parameters of neuronal cell function, which can be measured in easily obtained tissues, such as blood cells, as potential markers of the chemically-induced alterations occurring in the nervous system. This review includes a comparative analysis of the effects of mercurials on calcium signalling in the neuroadrenergic PC12 cells and rat splenic T lymphocytes in an attempt to characterize this second messenger system as a potential indicator of subclinical toxicity. The suitability of neurotransmitter receptors in blood cells, such as the sigma binding sites, as biological markers of psychiatric disorders is also discussed.

Animals↗
PubMedDate not supplied

Interaction of mercury compounds with muscarinic receptor subtypes in the rat brain.

The in vitro effects of mercuric chloride (HgCl2) and methylmercury (CH3HgOH) on the M1 and M2 muscarinic receptor subtypes were investigated in rat brain cortical membranes. HgCl2 and CH3HgOH were almost equipotent in inhibiting the binding of [3H]telenzepine to M1 receptors (IC50s = 2.2 and 3.4 microM, respectively). Conversely, HgCl2 was a thirty-fold more potent inhibitor of [3H]AF-DX 384 binding to M2 sites than CH3HgOH (lC50s = 5 and 149 microM, respectively). In all cases HgCl2 showed steep and monophasic inhibition curves, whereas those of CH3HgOH were biphasic (M1) or shallow (M2). CH3HgOH-induced inhibition of both [3H]telenzepine and [3H]AF-DX 384 binding was of the competitive type, while HgCl2 caused a pronounced reduction of the Bmax value associated with a small change in affinity. CH3HgOH also decreased the affinity of the agonist carbachol for M1 and M2 receptors, while inorganic mercury had minimal effects on the carbachol dose-response curves. These results indicate that inorganic and organic mercury differ in their interaction with muscarinic receptor subtypes and that M1 receptors may represent a preferential target for their effects.

Animals↗
PubMedDate not supplied

[Telematics equipment for poison control surveillance. Its applications in the health management of relevant chemical incidents].

Health management of major chemical incidents requires a close collaboration between rescuers (on the disaster site and in the emergency department) and the poison center. The study tested telematic technologies allowing telepresence and teleconsulting, a real time and continuous connection among health care personnel and toxicologists involved in the management of the emergency. The link between the poison center (PC) and the emergency department in the local hospital is provided by a ISDN operating video conferencing system, while the data transmission from the site of the accident to the PC is achieved with a personal computer and GSM cellular data transmission. Toxicological databases and risk assessment software are integrated in the system, to support information sharing. To test such instruments in operative nearly realistic conditions, the main phase of the study has implemented simulated chemical disasters in different locations in Italy. Instruments for telepresence and teleconsulting have been effectively utilized to evaluate from a remote location the scenario and the severity of the accident, by inspecting either specific details or the whole scene, to enable PC guiding the triage of the victims before and after hospitalization, to utilize and share data, such as intervention protocols or patient records, and to document all the activities. In summary, this experience shows that the telematic link allows the toxicologists of the poison center to rapidly understand the situation, and to correctly learn about the conditions of patients with the help of images. The results of this study indicate the valuable benefits of telematic instruments for the health care in case of major chemical disasters occurring in a remote geographical location or in an area which lacks local toxicological experts, where specialized expertise can be achieved by the use of telematic technologies.

Emergency Service, Hospital↗