A method for the fractionation of sheep rumen epithelium with limited mitochondrial breakage is described. The distributions of the enzymes of the 3-hydroxy-3-methylglutaryl-CoA pathway of ketogenesis indicate that this process is exclusively mitochondrial. Enzyme activities are sufficient to account for the ketogenic rates found in vivo. The failure of (-)-hydroxycitrate to block ketogenic flux supports this view. 3-Hydroxybutyrate dehydrogenase activity is largely associated with particulate material in the mitochondrial fraction. ATP citrate lyase activity was found, with appreciable acetoacetyl-CoA thiolase and 3-hydroxy-3-methylglutaryl-CoA synthase in the cytoplasmic fraction.

Tranexamic acid (TXA) allergy is extremely rare. An 80-year-old woman without prior exposure to TXA underwent elective knee replacement. Shortly after induction of anaesthesia and intravenous TXA, she developed hypotension, tachycardia, and facial erythema accompanied by a raised serum tryptase. Later, skin prick and intradermal testing confirmed positive responses to TXA in high dilution and with negative results to the other drugs used. While neuromuscular blocking agents, opiates, and antibiotics remain the most frequent cause of anaphylaxis during anaesthesia, allergy to TXA should always be borne in mind and requires skin testing for confirmation as there are presently no blood tests available.

By using an antiserum raised against rat liver tyrosine aminotransferase, it was shown that about 60% of tryptophan aminotransferase activity in rat liver extracts is catalysed by this enzyme. Induction of tryptophan aminotransferase activity by intraperitoneal injections of tryptophan or triamcinolone can be entirely attributed to the effects of these agents on tyrosine aminotransferase. The origin of the other 40% of tryptophan aminotransferase activity remains to be established. This activity increases after starvation for 48 h. It is unlikely that tryptophan transamination plays a quantitatively important role in the metabolism of tryptophan by the liver.

BackgroundThe renin-angiotensin system (RAS) protects the circulation against sudden falls in systemic blood pressure via generation of angiotensin II (AII). Previously, we demonstrated that patients with anaphylaxis involving airway angioedema and cardiovascular collapse (AACVS) had significantly increased “I” gene polymorphisms of the angiotensin-converting-enzymes (ACE). This is associated with lower serum ACE and AII levels and was not seen in anaphylaxis without collapse nor atopics and healthy controls.ObjectivesTo examine the angiotensinogen (AGT-M235T) and chymase gene (CMA-1 A1903G) polymorphisms in these original subjects.Method122 patients with IgE-mediated anaphylaxis, 119 healthy controls and 52 atopics had polymorphisms of the AGT gene and chymase gene examined by polymerase chain reactions and gel electrophoresis. Their previous ACE genotypes were included for the analysis.ResultsAGT-MM genes (associated with low AGT levels) were significantly increased in anaphylaxis (Terr’s classification). When combined with ACE, anaphylaxis showed increased MM/II gene pairing (p<0.0013) consistent with lower RAS activity. For chymase, there was increased pairing of MM/AG (p<0.005) and AG/II and AG/ID (p<0.0073) for anaphylaxis consistent with lower RAS activity. A tri-allelic ensemble of the 6 commonest gene combinations for the healthy controls and anaphylaxis confirmed this difference (p=0.0001); for anaphylaxis, genes were predominately MM/AG/II or ID, while healthy controls were DD/MT/AG or GG patterns.ConclusionOur gene polymorphisms show lower RAS activity for anaphylaxis especially AACVS. Animal models of anaphylaxis are focused on endothelial nitric oxide (eNO) which is shown to be the mediator of fatal shock and prevented by eNO-blockade. The interaction of AII and eNO controls the microcirculation in man. High serum AII levels reduce eNO activity, so higher RAS-activity could protect against shock. Our data shows low RAS activity in anaphylaxis especially AACVS, suggesting the influence of these genes on shock are via AII levels and its effects on eNO.

Sulfamethoxazole and dapsone share the same sulphonamide ring with similar antibacterial effects. Detailed studies of dapsone show extensive effects on the immune system with the reduced generation of oxygen free radicals (ROS) and inhibition of neutrophil (NΦ) myeloperoxidase. These effects reduce intra and extracellular ROS reducing endothelial damage, lipid peroxidation and apoptosis. The bacterial peptide N-formyl-met-leu-phe (fMLP) activates the NΦ via its formyl peptide receptor (FPR) generating ROS much of which is extracellular. The FPR receptor also induces cell migration, granule secretion and lysosomal activation. Dapsone very significantly reduces fMLP activation of NΦ, giving anti-inflammatory effects. Interestingly phorbol 12-myristate 13-acetate (PMA), a well characterised activator of protein kinase C is less inhibited by dapsone. There are no comparable studies with cotrimoxazole despite its structural similarity. UK clinical studies of cotrimoxazole in Idiopathic pulmonary fibrosis (IPF), suggest protection against sudden severe exacerbations. Cotrimoxazole is thought to act via its anti-bacterial properties with data showing pathogen carriage in a third of new IPF cases. Oxidative stress is increased in IPF and limited studies show that peripheral monocyte (MΦ) depletion via a charcoal column in IPF exacerbations has reduced the 30 day mortality. In fibrotic organ injury, recruitment of MΦ appears critical and blocking MΦ activation and recruitment arrests the fibrotic process. We have examined by flow cytometry the effects of oral cotrimoxazole upon NΦ and MΦ activation in IPF patients on long-term treatment and healthy controls at baseline and after 1 week of cotrimoxazole. The commercial kit PHAGOBURST (Glycotope Biotechnology) was used, which allows quantitative determination of leucocyte oxidative burst in whole blood following stimulation by opsonized E Coli, PMA and fMLP.FindingsDespite the small numbers to date, similar to dapsone there is a significant blocking of oxidative burst to fMLP in NΦ and MΦ pre- and post cotrimoxazole with a similar trend in IPF. There is also some reduction in PMA oxidative burst, but none to E.coli. The reduced MΦ stimulation may reflect the lower MΦ bloods counts. If NΦ and MΦ ROS generation are reduced by cotrimoxazole, this may stabilise the disease process protecting against severe exacerbations.Abstract P49 Table 1Neutrophils Mean fluorescence*±SEM of stimulated cells (arbitrary units)Healthy controls(HC) n=9 No treatmentsHealthy controls n=6 post-Cotrimoxazole 7 days (960 mgBD)Paired t test +significance at the 5% level (pre- and post Cotrimoxazole n=6)IPF on long-term Cotrimoxazole (mean treatment duration 23 months, Cotrimoxazole (960 mgBD) n=8Mann Whitney U test HC versus IPF +significance at the 5% level Mean neutrophil blood count 109/l (SEM)3.32±0.243.43±0.164.49±0.39PMA Nφ7014±16235903±1503p=0.6833866±823p=0.117fMLP Nφ989±242246±244p=0.015+448±407p=0.08E coli Nφ4417±4473302±815p=0.3313606±358p=0.189Monocytes Mean fluorescence*±SEM of stimulated ...