Objectives:  To evaluate the efficacy and safety of a therapeutic bacteriophage preparation (Biophage‐PA) targeting antibiotic‐resistant Pseudomonas aeruginosa in chronic otitis. Design:  Randomised, double‐blind, placebo‐controlled Phase I/II clinical trial approved by UK Medicines and Healthcare products Regulatory Agency (MHRA) and the Central Office for Research Ethics Committees (COREC) ethical review process. Setting:  A single specialist university hospital. Participants:  24 patients with chronic otitis with a duration of several years (2–58). Each patient had, at the time of entry to the trial, an ear infection because of an antibiotic‐resistant P. aeruginosa strain sensitive to one or more of the six phages present in Biophage‐PA. Participants were randomised in two groups of 12 treated with either a single dose of Biophage‐PA or placebo and followed up at 7, 21 and 42 days after treatment by the same otologist. Ears were thoroughly cleaned on each occasion and clinical and microbiological indicators measured. Main outcome measures:  Physician assessed erythema/inflammation, ulceration/granulation/polyps, discharge quantity, discharge type and odour using a Visual Analogue Scale (VAS). Patients reported discomfort, itchiness, wetness and smell also using a VAS. Bacterial levels of P. aeruginosa and phage counts from swabs were measured initially and at follow‐up. At each visit patients were asked about side effects using a structured form. Digital otoscopic images were obtained on days 0 and 42 for illustrative purposes only. Results:  Relative to day 0, pooled patient‐ and physician‐reported clinical indicators improved for the phage treated group relative to the placebo group. Variation from baseline levels was statistically significant for combined data from all clinic days only for the phage treated group. Variation from baseline levels was statistically significant for the majority of the patient assessed clinical indicators only for the phage treated group. P. aeruginosa counts were significantly lower only in the phage treated group. No treatment related adverse event was reported. Conclusion:  The first controlled clinical trial of a therapeutic bacteriophage preparation showed efficacy and safety in chronic otitis because of chemo‐resistant P. aeruginosa.

No abstract

We have investigated the mechanism by which cultured endothelial cells generate L-arginine (L-Arg), the substrate for the biosynthesis of endothelium-derived relaxing factor. When Arg-depleted endothelial cells were incubated in Krebs' solution for 60 min, L-Arg levels were significantly (9.7-fold) elevated. The generation of L-Arg coincided with a substantial decrease (90%) in intracellular L-glutamine (L-Gln), whereas all other amino acids were virtually unaffected. Changes in calcium, pH, or oxygen tension had no effect on L-Arg generation, which was, however, prevented when the cells were incubated in culture medium containing L-Gln. The Arg-Cit cycle appears to be the equivalent in the endothelial cell to the formation of urea by the liver. The biosynthesis of endothelium-derived relaxing factor may, therefore, not only produce a powerful vasodilator but also relieve the endothelial cell of excess nitrogen.Endothelium-derived relaxing factor (EDRF) has been identified as nitric oxide (NO) or a closely related molecule derived from the guanidino group of L-arginine (L-Arg) (1-3). Its biosynthesis involves a cytosolic (4) or microsomal (5) calcium/calmodulin and NADPH-dependent monooxygenase, which catalyzes the conversion of L-Arg to L-citrulline (L-Cit) and NO, or an intermediate giving rise to NO formation. Similar enzymes have been identified in cytotoxic macrophages (6) and various regions of the brain (7, 8).Interestingly, L-Arg relaxes freshly isolated vascular preparations and potentiates the release of EDRF from cultured endothelial cells only when these tissues and cells are deprived of L-Arg for 24 hr (3, 9-12). These findings indicate that the endothelial L-Arg pool (0.1-0.8 mM in cultured compared with 2-4 mM in freshly isolated endothelial cells; refs. 11-13) can be depleted and that its availability then becomes rate-limiting for EDRF biosynthesis. Little is known about the pathway(s) by which the endothelium synthesizes or metabolizes L-Arg. We have found (11) that cultured endothelial cells generate L-Arg from an intracellular source and that this process is linked to the release of EDRF. They can also convert L-Cit to L-Arg (13), and we proposed that this pathway may help endothelial cells to maintain sufficient levels of L-Arg during periods of prolonged EDRF release (14). We have now investigated the mechanism by which endothelial cells generate L-Arg and whether urea cycle intermediates play a role in L-Arg biosynthesis. Determination of Intracellular Amino Acid Levels by HPLC/Fluorescence Detection Analysis. Endothelial cells from bovine aorta (15) were grown on Cytodex 3 microcarrier beads (Pharmacia) in Dulbecco's modified Eagle's medium (DMEM; Flow Laboratories) containing 0.6 mM L-Arg, 4 mM L-Gln, and 10% (vol/vol) fetal calf serum (FCS). The confluent cells were either used directly (nondepleted cells) or transferred to Eagle's minimum essential medium (MEM) without L-Arg and FCS but containing 2 mM L-Gln for 24 hr prior to the experiment. They were then washed 5-10 times wi...

This study reports plasma levels of a specific nonenzymatic peroxidation product of arachidonic acid, esterified 8-epi-PGF2~, from healthy-and NIDDM individuals as an index of oxidative stress in vivo. Plasma 8-epi-PGF2,~ was isolated by solid-phase extraction on a C~s followed by an NH2 cartridge and analyzed by GC-MS/NICI as PFB-ester/TMS-ether derivative. We found that the average concentration of esterified 8-epi-PGF2~ among NIDDM subjects (0.93 + 0.07 riM, n = 39) was higher (P < 0.0001, Mann-Whitney test) than in healthy individuals (0.28 + 0.04 nM, n = 15). These data indicate that NIDDM is associated with increased plasma lipid peroxidation.

A complete separation of myo-inositol 1,4,5-[4,5-(32)P]trisphosphate prepared from human erythrocytes, and myo-[2-3H]inositol 1,3,4-trisphosphate prepared from carbachol-stimulated rat parotid glands [Irvine, Letcher, Lander & Downes (1984) Biochem. J. 223, 237-243], was achieved by anion-exchange high-performance liquid chromatography. This separation technique was then used to study the metabolism of these two isomers of inositol trisphosphate in carbachol-stimulated rat parotid glands. Fragments of glands were pre-labelled with myo-[2-3H]inositol, washed, and then stimulated with carbachol. At 5s after stimulation a clear increase in inositol 1,4,5-trisphosphate was detected, with no significant increase in inositol 1,3,4-trisphosphate. After this initial lag however, inositol 1,3,4-phosphate rose rapidly; by 15s it predominated over inositol 1,4,5-trisphosphate, and continued to rise so that after 15 min it was at 10-20 times the radiolabelling level of the 1,4,5-isomer. In contrast, after the initial rapid rise (maximal within 15s), inositol 1,4,5-trisphosphate levels declined to near control levels after 1 min and then rose again very gradually over the next 15 min. When a muscarinic blocker (atropine) was added after 15 min of carbachol stimulation, inositol 1,4,5-trisphosphate levels dropped to control levels within 2-3 min, whereas inositol 1,3,4-trisphosphate levels took at least 15 min to fall, consistent with the kinetics observed earlier for total parotid inositol trisphosphates [Downes & Wusteman (1983) Biochem. J. 216, 633-640]. Phosphatidylinositol bisphosphate (PtdInsP2) from stimulated and control cells were degraded chemically to inositol trisphosphate to seek evidence for 3H-labelled PtdIns(3,4)P2. No evidence could be obtained that a significant proportion of PtdInsP2 was this isomer; in control tissues it must be less than 5% of the total PtdInsP2 radiolabelled by myo-[2-3H]inositol. These data indicate that, provided that inositol 1,4,5-trisphosphate is studied independently of inositol 1,3,4-trisphosphate, the former shows metabolic characteristics consistent with its proposed role as a second messenger for calcium mobilization. The metabolic profile of inositol 1,3,4-trisphosphate is entirely different, and its function and source remain unclear.

While a damaged endothelium is recognised to be a key accessory to diabetic macroangiopathy, awareness is developing that impairments concerning endothelium- and nitric oxide (NO)-dependent microvascular function, may contribute to several other corollaries of diabetes, such as hypertension, dyslipidaemia and in vivo insulin resistance. There are now several reports describing elevations in specific oxidant stress markers in both insulin resistance syndrome (IRS) and diabetes, together with determinations of reduced total antioxidant defence and depletions in individual antioxidants. Such a pro-oxidant environment in diabetes may disrupt endothelial function through the inactivation of NO, resulting in the attenuation of a fundamental anti-atherogenic and euglycaemic vascular influence. Indeed, experimental and clinical data suggest that the supplementation of insulin resistant or diabetic states with antioxidants such as vitamin E, normalises oxidant stress and improves both endothelium-dependent vasodilation and insulin sensitivity. However, the promising potential efficacy of antioxidant therapy in cardiovascular disease and diabetes, in either a primary or secondary preventative role, awaits definitive clinical demonstration.

ObjectiveDesign A prospective study. Setting Nuffield Department of Obstetrics and Gynaecology, Oxford and The William HarveyInstitute, London.Sample Three groups of women: those with pre-eclampsia (n = 19), control pregnant women (n = 19) matched for gestation, age and parity and a group of non pregnant individuals of reproductive age (n = 7).Methods Citrated plasma was stored at -80°C with 20 pmol 0 hydroxytoluene to prevent autooxidation. Plasma samples were assayed for levels of 8 epi-prostaglandin F?,, lipid hydroperoxides, malondialdehyde and also the lipid soluble antioxidant vitamin E.Results There were no differences in 8 epi-prostaglandin F,, lipid peroxide or malondialdehyde levels between the groups of women with pre-eclampsia and those acting as pregnant controls. However, lipid hydroperoxides and malondialdehyde were significantly raised in both preeclampsia and normal pregnancy, compared with nonpregnant women. Vitamin E levels were similar in women with pre-eclampsia and those with a normal pregnancy, but in both groups levels were significantly higher than in nonpregnant women. ConclusionCirculating markers of oxidative stress are raised in normal pregnancy and preeclampsia.To determine whether circulating markers of oxidative stress are elevated in preeclampsia when appropriate precautions are taken to prevent in vitro oxidation

No abstract