Review of petroleum toxicity in marine reptiles

Worldwide petroleum exploration and transportation continue to impact the health of the marine environment through both catastrophic and chronic spillage. Of the impacted fauna, marine reptiles are often overlooked. While marine reptiles are sensitive to xenobiotics, there is a paucity of petroleum toxicity data for these specialized fauna in peer reviewed literature. Here we review the known impacts of petroleum spillage to marine reptiles, specifically to marine turtles and iguanas with an emphasis on physiology and fitness related toxicological effects. Secondly, we recommend standardized toxicity testing on surrogate species to elucidate the mechanisms by which petroleum related mortalities occur in the field following catastrophic spillage and to better link physiological and fitness related endpoints. Finally, we propose that marine reptiles could serve as sentinel species for marine ecosystem monitoring in the case of petroleum spillage. Comprehensive petroleum toxicity data on marine reptiles is needed in order to serve as a foundation for future research with newer, unconventional crude oils of unknown toxicity such as diluted bitumen.

     

Computer-aided system for health economic evaluation

Background  Health policy makers are usually stranded by the complicated infrastructure and intensive computation related to economic evaluation.
Objectives  It is therefore valuable to develop a computer-aided tool to help health personnel to perform economic evaluation with ease.
Method  The infrastructure for economic evaluation was first designed. Markov process with micro-simulation was applied to model the disease natural history or lifetime sequale to project the effectiveness by comparing all possible decisions. All the essential elements of economic evaluation together with sensitivity analysis are encoded in this computer-aided software written with SAS Screen Control Language in user-defined menu style.
Illustration  Screening versus no screening for colorectal cancer was used as an example.
Conclusion  The computer-aided model for economic evaluation was developed in this study. It is anticipated that the flexibility and user-defined menu style facilitate the wide application of economic evaluation to health care intervention program.     

Graphite oxide bulk modified carbon paste electrode for the selective detection of dopamine: A voltammetric study

A novel electrochemical sensor for the selective and sensitive detection of dopamine (DA) in presence of large excess of ascorbic acid (AA) and uric acid (UA) at physiological pH was developed by the bulk modification of carbon paste electrode (CPE) with biocompatible graphite oxide (GO). Very small quantity of GO in carbon paste matrix imparted selectivity through electrostatic interactions. The modifier was characterized using infrared spectroscopy and powder X-ray diffraction. Large peak separation, good sensitivity and stability allow this modified electrode to analyze DA individually and simultaneously along with AA and UA. Applying differential pulse technique, DA could be detected even in the presence of 1000 fold excess of AA and UA. A linear dynamic range of 0.07–70 μM with detection limit of 1.5 × 10⁻⁸ M was obtained for DA. None of the bulk modified electrodes reported in the literature have shown such a low detection limit at the physiological pH. The practical application of the modified electrode was demonstrated by spiking the human blood serum and cerebral fluid with dopamine and the results obtained were satisfactory.     

Effect in cat locus coeruleus lesions on the response of cerebral blood flow and cardiac output to altered paCO2

In pentobarbital-anesthetized cats, over arterial p_aCO₂ values of 20–60 mm Hg, cerebral blood flow (CBF, Xenon) and cardiac output (CO, thermal dilution) show positively inflected curves with slopes significantly greater than zero. To examine the role of the locus coeruleus (LC) in these responses, bilateral stereotactic thermo-coagulation lesions of the LC were made. The effect of lesions confirmed to involve the LC bilaterally (n= 10), were compared with the effects of misdirected lesions placed in the cerebellum abd lateral to the LC (n= 10) and sham lesions (n= 10). Ted days after the lesioning procedure, the animals were re-anesthetized with pentobarbital and p_aCO₂ response curves were determined for CBF and CO prior to and following intravenous administration of propranolol (1 mg/kg, i.v.). The results obtained with the sham-operated animals and the animals with lesions outside of the LC were indistinguishable. Bilateral LC lesions had no significant effect on normocapnic CBF as compared to control animals. They did, however, significantly reduce the slope of the CBF p_aCO₂ response curve. Propranolol produced a significant reduction in CBF in lesioned and non-lesioned animals measured at all levels of pCO₂ and did not alter the slope of the pCO₂ response curve for any group as compared to predrug values. Bilateral lesions of the LC did not significantly alter either normacapnic CO or the slope of the CO-p_aCO₂ relationship, but did reduce the elevation in mean arterial blood pressure otherwise observed during hypercarbia. Measurement of norepinephrine levels in cortex indicate a close indicate a correlation between the ability of the lesion to reduce norepinephrine content and produce the observed physiological effects. The results of these experiments suggest that the hypercapnic response of CBF, but not CO to arterial p_aCO₂ is modulated by systems which traverse the dorsal brainstem. The role of the locus coeruleus-catecholamine cell bodies in this effect, however, must be considered speculative until further transmitter-selective interventions are carried out.