Quantification of potentially toxic elements in food material by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) via pressed pellets.

Here, we validated a protocol for the elemental analysis of plant and food materials using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and pressed pellets in compliance with the Green Chemistry principles, i.e. avoiding the use of hazardous reagents. The protocol included sample pre-treatment, preparation of pellets, and LA-ICP-MS optimisation for the food sample matrix using leaf certified reference materials. Sample homogenisation and particle size reduction (∼10 µm) for samples with larger initial particle sizes proved crucial in improving signal stability and analytical results, whereas the raster mode was preferred over spot mode for greater accuracy. The validation of the technique was successful for determination of Mn, Ni, Cu, Zn, As, Se, Cd and Pb (z-score values  ≤2). We propose LA-ICP-MS using pressed pellets as an alternative to ICP-MS in food analysis.

Transition metal triflate catalyzed conversion of alcohols, ethers and esters to olefins.

Herein, we report an efficient transition metal triflate catalyzed approach to convert biomass-based compounds, such as monoterpene alcohols, sugar alcohols, octyl acetate and tea tree oil, to their corresponding olefins in high yields. The reaction proceeds through C-O bond cleavage under solvent-free conditions, where the catalytic activity is determined by the oxophilicity and the Lewis acidity of the metal catalyst. In addition, we demonstrate how the oxygen containing functionality affects the formation of the olefins. Furthermore, the robustness of the used metal triflate catalysts, Fe(OTf)3 and Hf(OTf)4, is highlighted by their ability to convert an over 2400-fold excess of 2-octanol to octenes in high isolated yields.

Polymyxin B protects horses against induced endotoxaemia in vivo.

REASONS FOR PERFORMING STUDY: A safe, affordable and effective treatment for endotoxaemia in horses is needed in order to reduce the incidence of this potentially fatal condition. OBJECTIVE: To evaluate the effect of polymyxin B (PMB) on signs of experimentally-induced endotoxaemia. HYPOTHESIS: PMB ameliorates the adverse effects of endotoxaemia without causing nephrotoxicity. METHODS: Four groups of 6 healthy mature horses each received 20 ng endotoxin/kg bwt i.v. over 30 mins. Additionally, each group received one of the following i.v.; 5000 u PMB/kg bwt 30 mins before endotoxin infusion; 5000 u PMB/kg bwt 30 mins after endotoxin infusion; 1000 u PMB/kg bwt 30 mins prior to endotoxin infusion; or saline. Clinical response data and samples were collected to determine neutrophil count, serum tumour necrosis factor (TNF) activity, plasma thromboxane B2 concentration and urine gamma glutamyltranspeptidase (GGT) to creatinine ratio. RESULTS: Treatment with PMB before or after administration of endotoxin significantly reduced fever, tachycardia and serum TNF, compared to horses receiving saline. The differences in response to endotoxin were greatest between horses that received saline vs. those that received 5000 u PMB/kg bwt prior to endotoxin. Urine GGT:creatinine did not change significantly. CONCLUSIONS AND POTENTIAL RELEVANCE: This study indicates that PMB may be a safe and effective treatment of endotoxaemia, even when administered after onset. Although nephrotoxicity was not demonstrated with this model, caution should be exercised when using PMB in azotaemic patients.

Evaluation of polymyxin B in an ex vivo model of endotoxemia in horses.

OBJECTIVE: To evaluate effects of polymyxin B sulfate (PMB) on response of horses to endotoxin, using an ex vivo model. ANIMALS: 8 healthy horses. PROCEDURE: In a crossover design, 3 doses of PMB (100, 1,000, and 10,000 U/kg of body weight) and physiologic saline solution (control) were evaluated. Prior to and for 24 hours after administration of PMB, blood samples were collected into heparinized tubes for use in 2 assays. For the endotoxin-induced tumor necrosis factor (TNF) assay, blood samples were incubated (37 C for 4 h) with 1 ng of Escherichia coli or Salmonella Typhimurium endotoxin/ml of blood. Plasma was harvested and assayed. For the residual endotoxin activity assay, plasma was collected into sterile endotoxin-free borosilicate tubes, diluted 1:10 with pyrogen-free water, and incubated for 10 minutes at 70 C. Escherichia coli endotoxin (0.1 or 1 ng/ml of plasma) was added to the thawed samples prior to performing the limulus ameobocyte lysate assay. Serum creatinine concentrations were monitored for 1 week. RESULTS: Compared with baseline values, PMB caused a significant dose- and time-dependent decrease in endotoxin-induced TNF activity. Compared with baseline values, residual endotoxin activity was significantly reduced after administration of 10,000 U of PMB/kg. Compared with baseline values, 1,000 and 5,000 U of PMB/kg should inhibit 75% of endotoxin-induced TNF activity for 3 and 12 hours, respectively. Serum creatinine concentrations remained within the reference range. CONCLUSION AND CLINICAL RELEVANCE: Results of the study suggest that PMB is a safe, effective inhibitor of endotoxin-induced inflammation in healthy horses.

Complications associated with anaesthesia for ocular surgery: a retrospective study 1989-1996.

This retrospective study was initiated to identify complications of anaesthesia occurring during ocular surgery. Records of 74 horses anaesthetised for eye enucleation, 65 horses anaesthetised for surgery of the eye and adnexa, and 51 horses anaesthetised for splint bone excision were reviewed. Fifty-three percent of the horses anaesthetised for eye enucleation moved during surgery which was significantly more frequent than in the other groups (P = 0.001). The incidence of moving was significantly reduced by use of an anaesthetic gas analyser for monitoring (P = 0.001). Transient hypertension was measured in 6 horses during removal of the eye. One horse experienced a momentary decrease in heart rate from 36 to 26 beats/min at the start of surgery involving a mass on the third eyelid. The incidence of unsatisfactory recovery from anaesthesia involving multiple attempts to stand was significantly greater after ocular surgery than after splint bone excision (P = 0.036). Our conclusions were 1) the oculocardiac reflex was not active in these horses undergoing ocular surgery, 2) increased attention must be paid to provision of analgesia and adequate depth of anaesthesia, which may be facilitated by use of an anaesthetic gas analyser and 3) horses were at greater risk for unsatisfactory recoveries from anaesthesia after ocular surgery.

Tourniquet-induced enmg changes in arthroscopic anterior cruciate ligament reconstruction. A comparison of low and high-pressure tourniquet systems.

BACKGROUND AND AIMS: The use of a tourniquet during surgery is associated with a risk of neurological disorders. We compared whether a new tourniquet system using low pressure (250 mmHg) is safer than a standard tourniquet system using higher inflation pressure (350 mmHg). MATERIALS AND METHODS: Thirty-one patients (ASA I-II), ages 16-48 years, were studied with ENMG preoperatively and 3 weeks postoperatively following arthroscopic anterior cruciate ligament reconstruction. Tourniquet times varied between 30 and 146 min. RESULTS: Postoperative slowing of motor and sensory conduction was observed, as well as an increase of the minimum peroneal F-response and tibial H-reflex latencies. The sensory amplitude of the sural nerve decreased. Vastus medialis of the quadriceps femoris muscle showed a reduced interference pattern in ENMG in maximal voluntary effort postoperatively. No differences were found in measured results between the low and high pressure tourniquet systems. CONCLUSIONS: Slight postoperative ENMG alterations were demonstrated but the use of both tourniquet systems is safe within the limit of tourniquet times of less than 2 h.

Postmortem pink teeth phenomenon: an experimental study and a survey of the literature.

The appearance of pink teeth after death is a phenomenon long familiar to forensic dentists. Although the application of modern techniques has shed some light on its aetiology, elucidation of the ultimate mechanism underlying the phenomenon is still awaited. In this paper, previous literature on the subject is surveyed, and an experimental approach under standardized conditions to allow analysis of possible causes and biological mechanisms of the pink-teeth phenomenon in rats is described. The experimental results were consistent with most previous observations. It seems probable that colouration of the teeth would be found in those regions of the jaws where the blood is seeking on the basis of gravitation hypostasis. The primary red colouration is most likely due to haemoglobin derivatives within the necrotic pulp tissue in cases in which blood has accumulated in the head and the dependent lividity (hypostasis) is obstructed. The authors discuss the likely causes for the development of the pink teeth phenomenon. It seems that this phenomenon is more dependent on physical than chemical factors after death.