Effects of two alveolar recruitment manoeuvres (sustained inflation and stepwise) followed by positive end-expiratory pressure on cardiac output (measured with lithium dilution), invasive blood pressure and arterial oxygen tension in isoflurane-anaesthetised goats.

Alveolar recruitment manoeuvres (ARM) performed during general anaesthesia improve oxygenation; however cardiovascular depression may be observed. The aim of the study was to compare the effects of sustained inflation (SI) and stepwise ARMs on cardiac output (CO), mean arterial blood pressure and arterial oxygen tension (PaO2) in ten mechanically ventilated goats anaesthetised with isoflurane. In the SI ARM, peak inspiratory presure (PIP) was increased to 30 cmH2O and sustained for 20 s. In the stepwise ARM, the PIP was increased by 5 cmH2O each minute for three minutes from 10 to 25 cmH2O. Both ARMs were followed by positive end-expiratory pressure of 5 cmH2O. Paired lithium dilution CO measurements and arterial blood samples were obtained before and after each ARM. The order of the ARM was randomised and each goat was subjected to both techniques. Data was reported as median and interquartile range (IQR). Significance was set at 0.05. The median change in CO (measured by subtracting values after and before ARM) was -0.15 L min-1 (IQR -0.51; 0.03) and - 0.90 L min-1 (IQR -1.69; -0.58) for SI and stepwise ARM respectively (p = 0.04). The median change in PaO2 was 3 kPa (IQR -2.7; 7.6) and 0.4 kPa (IQR -3.4; 5.5) for SI and stepwise ARM respectively (p = 0.03). In conclusion, SI ARM causes less impact on CO and provides a better improvement in PaO2 compared to stepwise ARM in goats.

X-ray micro-computed tomography of postmortem brain tissue using potassium dichromate as a contrast agent.

No abstract available.

Effect of detomidine or romifidine constant rate infusion on plasma lactate concentration and inhalant requirements during isoflurane anaesthesia in horses.

OBJECTIVE: Influence of detomidine or romifidine constant rate infusion (CRI) on plasma lactate concentration and isoflurane requirements in horses undergoing elective surgery. STUDY DESIGN: Prospective, randomised, blinded, clinical trial. ANIMALS: A total of 24 adult healthy horses. METHODS: All horses were administered intramuscular acepromazine (0.02 mg kg-1) and either intravenous detomidine (0.02 mg kg-1) (group D), romifidine (0.08 mg kg-1) (group R) or xylazine (1.0 mg kg-1) (group C) prior to anaesthesia. Group D was administered detomidine CRI (10 µg kg-1 hour-1) in lactated Ringer's solution (LRS), group R romifidine CRI (40 µg kg-1 hour-1) in LRS and group C an equivalent amount of LRS intraoperatively. Anaesthesia was induced with ketamine and diazepam and maintained with isoflurane in oxygen. Plasma lactate samples were taken prior to anaesthesia (baseline), intraoperatively (three samples at 30 minute intervals) and in recovery (at 10 minutes, once standing and 3 hours after end of anaesthesia). End-tidal isoflurane percentage (Fe'Iso) was analysed by allocating values into three periods: Prep (15 minutes after the start anaesthesia-start surgery); Surgery 1 (start surgery-30 minutes later); and Surgery 2 (end Surgery 1-end anaesthesia). A linear mixed model was used to analyse the data. A value of p<0.05 was considered significant. RESULTS: There was a difference in plasma lactate between 'baseline' and 'once standing' in all three groups (p<0.01); values did not differ significantly between groups. In groups D and R, Fe'Iso decreased significantly by 18% (to 1.03%) and by 15% (to 1.07%), respectively, during Surgery 2 compared with group C (1.26%); p<0.006, p<0.02, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Intraoperative detomidine or romifidine CRI in horses did not result in a clinically significant increase in plasma lactate compared with control group. Detomidine and romifidine infusions decreased isoflurane requirements during surgery.

Breakage of two silicone endotracheal tubes during extubation.

Silicone endotracheal tubes broke during tracheal extubation of two dogs after uneventful anaesthesia. The remaining pieces were removed via endoscopy, and both dogs recovered with no further problems. A third silicone endotracheal tube broke while checking for cracks prior to its use. Biofilm formation on the surface of the endotracheal tube is thought to be the main cause of the breakage. Destruction of the biofilm is difficult, therefore exhaustive cleaning with detergents followed by vigorous brushing is recommended to break the interaction between the silicone surface and the biofilm. It is suggested that careful attention is paid to how tubes are cleaned and dried (in a hanging position), and that they are checked carefully for cracks prior to each use.

Analysis of the presence of cell proliferation-related molecules in the Tgf-ß3 null mutant mouse palate reveals misexpression of EGF and Msx-1.

The Tgf-ß(3) null mutant mouse palate presents several cellular anomalies that lead to the appearance of cleft palate. One of them concerns the cell proliferation of both the palatal medial edge epithelium and mesenchyme. In this work, our aim was to determine whether there was any variation in the presence/distribution of several cell proliferation-related molecules that could be responsible for the cell proliferation defects observed in these palates. Our results showed no difference in the presence of EGF-R, PDGF-A, TGF-ß(2), Bmp-2, and Bmp-4, and differences were minimal for FGF-10 and Shh. However, the expression of EGF and Msx-1 changed substantially. The shift of the EGF protein expression was the one that most correlated with that of cell proliferation. This molecule is regulated by TGF-ß(3), and experiments blocking its activity in culture suggest that EGF misexpression in the Tgf-ß(3) null mutant mouse palate plays a role in the cell proliferation defect observed.

Synthesis of modified nucleoside 3',5'-bisphosphates and their incorporation into oligoribonucleotides with T4 RNA ligase.

A simple procedure is described to prepare nucleoside 3'(2'),5'-bisphosphates from the corresponding nucleosides with the use of pyrophosphoryl chloride. This method is rapid, gives nearly quantitative yields and, most importantly, can be used for a variety of nucleosides with base and sugar modifications. Since 3',5'-bisphosphates are donors in the T4 RNA ligase reaction, a single residue can be enzymatically attached to the 3' end of oligoribonucleotides. By these procedures, five different ring-modified nucleosides and one sugar-modified nucleoside were incorporated onto the 3' end of (Ap)3C. In two cases, an additional step of synthesis with RNA ligase resulted in the modified nucleotide being located in an internal position in the oligonucleotide. Thus, a general method for the synthesis of oligoribonucleotides containing modified nucleosides is outlined. Since many of the modified nucleosides are fluorescent, oligomers containing them should be useful in a variety of physical and biochemical studies.