Search

The enzymatic synthesis of an azoanthraquinone by Perenniporia ochroleuca MUCL 41114 laccase was undertaken. The major product was purified and its structure identified by NMR, MS, IR analyses. In order to scale Lip the production of this azoanthraquinone named Laccase Acid Red 1, a commercial laccase from Trametes versicolor immobilised on perlite as an inexpensive carrier was used. Laccase Acid Red 1 showed lower toxicity than other commercial red dyes, was not mutagenic and displayed low ecotoxicity. In addition, its dyeing properties were assayed on polyamide and the industrial potential of the dye was demonstrated. To our knowledge, this is the first example of sulfonic azoanthraquinone production through enzymatic coupling of aromatic amine monomers. These results show promise for new, safer and environmental friendly routes to azo dye biosynthesis. (C) 2009 Elsevier ltd. All rights reserved.

A case of cardiac arrhythmias related to continuous thermodilution cardiac output (CCO) is reported. A sheep anaesthetized for experimental purpose was instrumented with a special Swan-Ganz catheter-type to be used for CCO measurements. One hour after starting the CCO monitoring, isolated ventricular extrasystoles were noticed on the electrocardiogram with an increasing frequency. Subsequently bursts of extrasystoles occurred. Atrioventricular dissociation was also observed. The peaks of temperature of the thermal filament were within the normal range and their presence was noticed when arrhythmias appeared. Mean blood pressure and cardiac output did not change during this episode. When the CCO was switched off, no more arrhythmias were observed. The CCO Swan-Ganz by itself did not generate any arrhythmia. The sheep recovered uneventfully. When arrhythmias occur during anaesthesia where CCO is used, a thermal filament induced origin of the arrhythmia must be considered.

Objective To evaluate the effect of local anaesthesia of the mesovarium on end-tidal isoflurane (F e ′iso) concentration and vital parameters during canine ovariohysterectomy. Study design Prospective, randomized, blinded study. Animals Twenty client-owned dogs undergoing elective ovariohysterectomy. Mean age 1.7 (±0.53, SD) years and mean body weight 21 kg (±5.9, SD). Methods Pre-medication was with intravenous acepromazine (0.02 mg kg−1) and methadone (0.1 mg kg−1). Anaesthesia was induced with propofol and maintained with isoflurane in oxygen. One group (n = 10) received local infiltration of the mesovarium with 0.5 mL lidocaine 2% and one group (n = 10) with 0.5 mL NaCl 0.9%. Heart (HR) and respiratory rates (fr), invasive mean arterial blood pressure (MAP) and F e ′isowere recorded. The F e ′iso was adjusted according to changes in HR, RR and MAP. Time points used for comparison were T1 (after induction of anaesthesia before surgery), T2 (after lidocaine infiltration of the mesovarium) and T3 (surgical manipulation of the ovaries). Data were analysed using a mixed model for repeated measurement anova and the Tukey adjustment. Results are presented as mean ± SD; p Results In both groups, HR and fr remained stable at the three time points. Mean values ranged from 84 to 94 beats minute−1 and from 10 to 14 breaths minute−1. The F e ′iso was significantly lower at T3 compared to T1 and mean values ranged from 0.95% to 1.24%. The mean arterial blood pressure was significantly higher at T3 compared to T1 and mean values ranged from 58 to 96 mm Hg. At none of the time points were there significant differences between the two groups for HR, fr, MAP or F e ′iso. Conclusion Neither an isoflurane sparing effect nor a difference in autonomic response to surgery was demonstrated following local anaesthesia of the mesovarium. Clinical relevance There appeared to be minimal benefit from local anaesthesia of the mesovarium during this study.

Objective—To evaluate a laparoscopic technique for implantation of a urinary catheter in the right paramedian area in male sheep and to determine feasibility, benefits, and risks for this technique. Design—Evaluation study. Animals—6 healthy male sheep (mean ± SD body weight, 42.16 ± 11.95 kg [92.75 ± 26.29 lb]). Procedures—Each sheep was anesthetized and positioned in dorsal recumbency. A 10-mm laparoscope was inserted in the right paramedian area between the xiphoid and preputial orifice. After creation of capnoperitoneum, grasping forceps were inserted in the left paramedian area at the level of the teats and used to immobilize the urinary bladder. A pigtail balloon catheter was implanted transcutaneously in the right paramedian area between the preputial orifice and teats and directed into the urinary bladder by use of laparoscopic guidance. The catheter was removed 10 days after implantation. Fourteen days after initial surgery, a second laparoscopy was performed to evaluate pathologic changes. Results—Inadvertent insertion of the first trocar into the rumen of 1 sheep was the only intraoperative complication encountered. Laparoscopic-assisted implantation of the urinary catheter was successfully performed in all sheep. No postoperative complications were detected. Conclusions and Clinical Relevance—Laparoscopic-assisted implantation of a urinary catheter in the right paramedian area was successfully performed and may be a feasible method for use in sheep. This method can be considered as an alternative to tube cystotomy performed by laparotomy.

The feasibility of the inversion of laser diffraction data for size and shape distributions by a constrained regularization method (Contin) has been investigated by computer simulation. Diffraction data are simulated for particles with elliptical projections. An iterative procedure is proposed to calculate the size and shape distribution. This method was able to recover both the size and shape distribution from simulated diffraction patterns of elliptical particles with different sizes and aspect ratios.

The feasibility of the inversion of laser diffraction data for size and shape distribution by neural networks has been investigated by computer simulation. Neural networks trained with diffraction patterns of elliptical particles with different sizes and aspect ratios (axis ratios) were able to recover simultaneously both the size and aspect ratio distributions in a few milliseconds on a common PC.

Background Workplace contamination by the use of volatile anesthetic agents should be kept to a minimum if a potential health hazard is to be minimised. Mask induction of animals is a common procedure. The present study investigates the efficiency of a novel scavenging double mask in reducing waste gas concentrations in the breathing zone of the anesthetist performing this procedure. Methods Twelve beagle dogs (ASA I) undergoing general anesthesia for a dental procedure were intravenously premedicated with medetomidine and butorphanol (10 μg/kg and 0.2 mg/kg). Anesthesia was induced via a custom-made scavenging mask using isoflurane in oxygen. In six dogs (group S), scavenging from the mask was performed whereas in six other dogs (group NS) the scavenging function was disabled. Isoflurane concentration was continuously measured with photoacoustic spectroscopy at the level of the shoulder of the anesthetist before and during mask induction and additionally during intubation. Statistical analysis was performed with a Student t- test and a Mann-Whitney U test (p < 0.05 for significance). Results The mean isoflurane concentration during baseline (premedication) was 1.8 ± 0.8 ppm and 2.3 ± 0.6 ppm in group S and NS respectively. This increased during mask induction to 2.0 ± 0.8 ppm and 11.2 ± 6.0 ppm respectively (p < 0.01). The maximum isoflurane concentration ranged from 0.7 ppm to 2.8 ppm and from from 8.3 ppm to 43.7 ppm in group S and NS respectively. Conclusion This double mask can be used to induce inhalation anesthesia in dogs. Scavenging from the mask significantly decreases the amount of waste anaesthetic gas concentrations in the breathing zone of the anesthetist. Therefore, such a system can be recommended whenever induction or maintenance of general anesthesia by mask is considered.

The methyl tunnel spectrum of copper acetate is studied at low temperatures by means of nuclear magnetic resonance level-crossing spectroscopy employing a field-cycling technique. The recovery of the proton magnetisation following saturation is measured as a function of magnetic field. Changing the magnetic field causes energy levels to cross when the methyl tunnel frequency is equal to one or two times the proton Larmor frequency, and abrupt changes in the recovered magnetisation, showing up as peaks or dips in a smooth background, reveal the positions of the level crossings. A variety of possible field cycles and sequences of cycles leads to a series of different experimental procedures which highlight different aspects of the thermodynamic properties of the system. In particular the dependence of the spectra on scanning schemes and on the thermodynamic preparation conditions is investigated. The experiments are understood in a semi-quantitative way in terms of a simple mathematical model for the thermal equilibration of three energy reservoirs, of which two are resonantly coupled at the level crossings. This simulation shows that, while the dominant processes have been clearly identified and incorporated in the model, some important factors remain to be explained. The methyl tunnel frequency in copper acetate is found to be (64+or-5) MHz.

The cardiovascular function of horses was less depressed during anaesthesia with isoflurane than during anaesthesia with halothane. Muscular microcirculation measured by laser Doppler flowmetry was significantly greater in horses anaesthetised with isoflurane.

A method, different from the classical ones, for studying internal motions - in particular reorientational and tunneling modulation of rotations - via NMR is described. Instead of looking for matching or resonance maxima in NMR T1−1 vs. T - curves [ where o (↗)≅ωo,with ρ the correlation rate and ωo: the Larmor frequency] we look for such maxima in NMR T1−1 vs. ωo - curves [where ω =↗o, with ω: the (tunneling)frequency]. These method, Nuclear Magnetic Resonance Relaxation Resonance (NMRRR), has marked advantages, which are discussed. A field cycling technique is presented. Typical results, for solid silane, are given.

We have performed nuclear magnetic resonance relaxation resonance measurements using the field-cycling technique, at temperatures below 15 K on solid Ge(CH3)4 at two values of the measuring field Bm = 0.41 and 0.94 T. We have detected Zeeman-tunnel resonances at the following values of the relaxation field Br: (0.5 ± 0.05)T, (0.6 ± 0.05)T, (1.2 ± 0.1)T, (1.35 ± 0.1)T and (0.8 ± 0.1)T. They correspond to the frequencies (21 ± 2)MHz, (26 ± 2)MHz, (51 ± 4)MHz, (58 ± 4)MHz and (34 ± 4)MHz. We assign them tentatively as being caused by four different tunnel frequencies, having the following values: v4t = (21 ± 2) MHz, v2t = (51 ± 4) MHz, v3t(34 ± 4)MHz, 12v1t = (58 ± 4) MHz. Our results contradict the the assumption of Lighthelm et al. [1], that the reorientation of the methyl groups in Ge(CH3)4 can be described by one correlation time.