Sample size and number of outcome measures of veterinary randomised controlled trials of pharmaceutical interventions funded by different sources, a cross-sectional study.

BACKGROUND: Randomised controlled trials (RCTs) are a key component of the veterinary evidence base. Sample sizes and defined outcome measures are crucial components of RCTs. To describe the sample size and number of outcome measures of veterinary RCTs either funded by the pharmaceutical industry or not, published in 2011. METHODS: A structured search of PubMed identified RCTs examining the efficacy of pharmaceutical interventions. Number of outcome measures, number of animals enrolled per trial, whether a primary outcome was identified, and the presence of a sample size calculation were extracted from the RCTs. The source of funding was identified for each trial and groups compared on the above parameters. RESULTS: Literature searches returned 972 papers; 86 papers comprising 126 individual trials were analysed. The median number of outcomes per trial was 5.0; there were no significant differences across funding groups (p = 0.133). The median number of animals enrolled per trial was 30.0; this was similar across funding groups (p = 0.302). A primary outcome was identified in 40.5% of trials and was significantly more likely to be stated in trials funded by a pharmaceutical company. A very low percentage of trials reported a sample size calculation (14.3%). CONCLUSIONS: Failure to report primary outcomes, justify sample sizes and the reporting of multiple outcome measures was a common feature in all of the clinical trials examined in this study. It is possible some of these factors may be affected by the source of funding of the studies, but the influence of funding needs to be explored with a larger number of trials. Some veterinary RCTs provide a weak evidence base and targeted strategies are required to improve the quality of veterinary RCTs to ensure there is reliable evidence on which to base clinical decisions.

Sponsorship bias and quality of randomised controlled trials in veterinary medicine.

BACKGROUND: Randomised controlled trials (RCTs) are considered the gold standard form of evidence for assessing treatment efficacy, but many factors can influence their reliability including methodological quality, reporting quality and funding source. The aim of this study was to examine the relationship between funding source and positive outcome reporting in veterinary RCTs published in 2011 and to assess the risk of bias in the RCTs identified. METHODS: A structured search of PubMed was used to identify feline, canine, equine, bovine and ovine clinical trials examining the efficacy of pharmaceutical interventions published in 2011. Funding source and outcomes were extracted from each RCT and an assessment of risk of bias made using the Cochrane risk of bias tool. RESULTS: Literature searches returned 972 papers, with 86 papers (comprising 126 individual RCTs) included in the analysis. There was found to be a significantly higher proportion of positive outcomes reported in the pharmaceutical funding group (P) compared to the non-pharmaceutical (NP) and 'no funding source stated' (NF) groups (P = 56.9%, NP = 34.9%, NF = 29.1%, p < 0.05). A high proportion of trials had an unclear risk of bias across the five criteria examined. CONCLUSIONS: We found evidence that veterinary RCTs were more likely to report positive outcomes if they have pharmaceutical industry funding or involvement. Consistently poor reporting of trials, including non-identification of funding source, was found which hinders the use of the available evidence.

Computer-aided design and synthesis of 5-substituted tryptamines and their pharmacology at the 5-HT1D receptor: discovery of compounds with potential anti-migraine properties.

The design and synthesis of a series of novel 5-substituted tryptamines with pharmacological activity at 5-HT1D and other monoamine receptors is described. Structural modifications of N- and C-linked (principally hydantoin) analogues at the 5-position were synthesized and their pharmacological activities were utilized to deduce significant steric and electrostatic requirements of the 5-HT1D and 5-HT2A receptor subtypes. Conformations of the active molecules were computed which, when overlaid, suggested a pharmacophore hypothesis which was consistent with the affinity and selectivity measured at 5-HT1D and 5-HT2A receptors. This pharmacophore is composed of a protonated amine site, an aromatic site, a hydrophobic pocket, and two hydrogen-bonding sites. A "selectivity site" was also identified which, if occupied, induced sensitivity for 5-HT1D over 5-HT2A in this series of molecules. The development and use of the pharmacophore models in compound design is described. In addition, the physicochemical constraints of molecular size and hydrophobicity required for efficient oral absorption are discussed. Utilizing the pharmacophore model in conjunction with the physicochemical constraints of molecular size and log DpH7.4 led to the discovery of 311C90 (6), a new selective 5-HT1D agonist with good oral absorption and potential use in the treatment of migraine.

Development of a novel series of trialkoxyaryl derivatives as specific and competitive antagonists of platelet activating factor.

The synthesis and structure-activity relationship (SAR) analysis of a novel series of trialkoxyaryl derivatives, as specific and competitive inhibitors of platelet activating factor (PAF), are described. Molecular modeling comparisons of PAF with the known antagonists Ginkgolide B and L-652731 led to the selection of N-[2-[(3,4,5-trimethoxybenzoyl)oxy]ethyl]-N,N,N-trimethylammonium iodide (1) from the Wellcome registry of compounds and to the synthesis of the lead compound N-[2-[[4-(hexyloxy)-3,5-dimethoxybenzoyl]oxy]ethyl]-N,N,N- trimethylammonium iodide (3, pKb 5.43). Further SAR considerations directed the design to 2-(hexyloxy)-1,3-dimethoxy-5-[4-(4-methylthiazol-5-yl)butyl] benzene (38) (pKb 7.14), a novel, specific, and competitive inhibitor of the PAF receptor in rabbit-washed platelets.

A quantitative structure-activity relationship approach to the minimization of albumin binding.

The binding of 2,6-disubstituted xanthones to human serum albumin (HSA) has been investigated using an ultrafiltration technique. A set of 26 compounds was chosen for study using a selection procedure aimed at minimizing the interparameter correlations, while ensuring that the physicochemical properties covered the maximum possible range of values. The magnitude of binding has been expressed as the compound concentration required to produce a specified bound concentration, in preference to equilibrium constants and number of albumin binding sites. Albumin binding was found to have a nonlinear dependence on the octanol-water partition coefficient (log P) and has been rationalized in terms of a simple binding model.

Perspectives in QSAR: computer chemistry and pattern recognition.

Computer chemistry allows a detailed description of properties for a wide range of molecular environments. In these respects it offers substantial benefits to the QSAR (Quantitative Structure Activity Relationship) analyst. Problems associated with the resulting wide data matrices are, it is proposed, amenable to solution through multivariate 'pattern recognition' techniques.

Xanthone additives for blood storage that maintain its potential for oxygen delivery. I. 2-Hydroxyethoxy- and 2-ethoxy-6-(5-tetrazoyl) xanthones in citrate-phosphate-dextrose-adenine (CPDA-1) blood.

Two xanthones, 2-hydroxyethoxy-6-(5-tetrazoyl) (BW A440C) and 2-ethoxy-6-(5-tetraozyl) (BW A827C), are members of a chemical series tested in vitro as potential additives to citrate-phosphate-dextrose-adenine (CPDA-1) medium for blood storage. P50 was maintained in the presence of these compounds during 42 days' storage by a partial maintenance of 2,3 diphosphoglycerate (2,3 DPG) and by a direct effect on hemoglobin previously reported for BW A827C. Red cell 2,3 DPG levels for BW A440C (n = 5), BW A827C (n = 5), and control (n = 6), respectively, were 3.38 +/- 0.47, 3.44 +/- 0.25, and 1.20 +/- 0.10 mM +/- SEM on day 7; 1.16 +/- 0.13, 1.52 +/- 0.37, and 0.16 +/- 0.02 mM on day 21; and 0.67 +/- 0.09, 0.61 +/- 0.08, and 0.06 +/- 0.006 mM on day 42. Red cell adenine triphosphate levels at the same time intervals were 1.84 +/- 0.09, 1.46 +/- 0.18, and 2.11 +/- 0.04 mM; 2.10 +/- 0.05, 2.07 +/- 0.17, and 2.13 +/- 0.05 mM; and 1.42 +/- 0.13, 1.37 +/- 0.13, and 1.38 +/- 0.06 mM, respectively. The degree of hemolysis was less with the addition of the compounds, and the methemoglobin formation, plasma Na+ and K+, and lactate production were unaffected by the compounds.

2,4-Diamino-5-benzylpyrimidines as antibacterial agents. 7. Analysis of the effect of 3,5-dialkyl substituent size and shape on binding to four different dihydrofolate reductase enzymes.

A group of trimethoprim (TMP) analogues containing 3,5-dialkyl(or halo)-4-alkoxy, -hydroxy, or -amino substitution were analyzed in terms of their inhibitory activities against four dihydrofolate reductase (DHFR) isozymes. Although selectivities were lower than with TMP, the activities against vertebrate DHFR were usually at least 2 orders of magnitude less than against enzymes from microbial sources. However, the profiles of activity were remarkably similar for rat, Neisseria gonorrhoeae, and Plasmodium berghei enzymes in all three series, although somewhat different for Escherichia coli DHFR, leading to the conclusion that the hydrophobic pockets are similar for the first three isozymes. Optimal substitution was reached with 3,5-di-n-propyl or 3-ethyl-5-n-propyl groups. Branching of chains at the alpha-carbon, which resulted in increased substituent thickness, was detrimental to E. coli DHFR inhibition in particular. MR is an inadequate parameter for use in correlating such substituent effects. Conformational changes of the more bulky inhibitors can be invoked to explain some differences in inhibitory pattern. Although log P explains simple substituent effects with the vertebrate DHFRs very well, it is insufficient in the more complex cases described here, where shape is clearly involved as well. Solvent-accessible surface areas were measured for TMP in E. coli and chicken DHFRs, where the coordinates are now known. The environment is more hydrophobic in the latter case; this can also be postulated for rat DHFR, which has a very similar activity profile. As with the mammalian isozymes, N. gonorrhoeae DHFR contains an active site phenylalanine replacing Leu-28 of E. coli DHFR, thus creating a more hydrophobic pocket. A similar replacement may also occur in the P.berghei isozyme. Selectivity for bacterial DHFR is dependent on the nature of the 4-substituent, being low for polar 4-hydroxy compounds but high for polar 4-amino analogues, possibly as a result of solvation differences. With complex substituents, the environment of each atom in the active site must be taken into account to adequately explain structure-activity relationships.

Comparative analysis of Haemophilus influenzae type b and Escherichia coli J5 lipopolysaccharides.

Haemophilus influenzae type b (HIB) and Escherichia coli J5 (J5) lipopolysaccharides (LPS) were examined to explore the basis of previously observed cross-protection. HIB-LPS and J5-LPS contained ketodeoxyoctonate, glucose, glucoheptose and glucosamine as common carbohydrate moieties, and laurate, myristate, beta-hydroxymyristate and palmitate as common fatty acids, although in different ratios. J5-LPS was five times more lethal than HIB-LPS for chick embryos. Weak serological cross-reactivity was observed by haemagglutination and two-dimensional immunoelectrophoresis. No significant cross-reactivity was demonstrated by enzyme-linked immunosorbent or toxicity-neutralisation assays. The cross-reactivity observed between HIB-LPS and J5-LPS was probably due to common components in the core glycolipid.

Performance on NBME Part I examination in relation to policies regarding use of test.

From 1971 to 1983, a number of administrative decisions were made at the University of Oklahoma College of Medicine regarding the National Board of Medical Examiners (NBME) Part I examination. Students' performance on this examination was found to be associated with administrative decisions that required (a) a passing score for promotion, (b) the student to take the examination, and (c) the student to take an integrated basic sciences review course. A modest improvement in student performance was noted when passage of the examination was made mandatory. The introduction of a review course into the curriculum effected a major upward change in scores that has persisted despite the removal of all requirements to pass, or even take, the Part I NBME examination.

Modification of the haemoglobin oxygen dissociation curve in whole blood by a compound with dual action.

2-Ethoxy-6-(5-tetrazolyl)xanthone reduces the oxygen affinity of blood by two mechanisms; firstly, by a direct effect on the haemoglobin molecule and secondly by maintaining levels of 2,3-diphosphoglycerate (DPG) in stored blood. This compound thus has potential as a blood storage additive which will improve the oxygen delivery of stored blood.

[Immunostimulation in an animal model using intestinal bacteria preparations]. / Immunstimulation in Tiermodellen mit Hilfe von Präparaten intestinaler Bakterien.

The treatment of mice with an injection preparation consisting of killed R-tribes of non-pathogenous E. coli caused an increase in microbicidic activities in the animal's blood and effects a significant protection against consecutive infections with Salmonella typhimurium. The enhancement of the animal' resistance capacity appears to be non-specific, and connected with the activity of leucocytes. Oral application of preparations of intestinal bacteria led to increased resistance against consecutive infections with Salmonella typhimurium and Haemophilus influenzae. Three different oral vaccines have been used: Streptococcus faecalis and E. coli, a viable vaccine of non-pathogenous Streptococcus faecalis and a viable vaccine of E. coli. The enhancement of the resistance can be attributed to an induction of the chemotactic efficiency of the animal neutrophilic cells. The chemotactic response of these cells seems to be enhanced. The mode of action of both the other oral vaccines remains obscure.

Application of S. faecalis and E. coli oral vaccines in humans and animals.

Vaccines of non-pathogenic intestinal bacteria for oral administration have been used in the therapy of chronic and recurrent infections by the German Medical Association for Microbiological Therapy for over three decades. Three different oral bacterial vaccines were used in particular: 1. A sterile autolysate of non-pathogenic S. faecalis and E. coli; 2. a viable non-pathogenic S. faecalis vaccine, and; 3. a viable non-pathogenic E. coli vaccine. Clinical studies indicate the safety and efficacy of these bacterial products, and suggest the stimulation of immune activities and competitive capacities of S. faecalis and E. coli as mode of action. In animal experiments, orally administered intestinal bacterial vaccines enhance the resistance of mice against subsequent challenge with lethal doses of Salmonella typhimurium and Haemophilus influenzae. Mice were allowed access to a viable suspension of either S. faecalis or E. coli for at least 3 weeks. They were then challenged with either of the two unrelated pathogens. Both pre-treatment procedures conferred significant protection of the animals. The mechanism of this protective action appears to involve modification of white blood cell kinetics in the mice. The peritoneal resident cell population in mice is significantly increased by S. faecalis treatment.

A rapid method to produce anti-gentamicin antibody.

The aminoglycoside antibiotic, gentamicin, was conjugated to erythrocytes or bovine serum albumin (BSA) by a simple procedure in which ECDI was employed as the coupling reagent. When rabbits were immunized by injecting gentamicin-goat erythrocyte conjugates, three kinds of antibody were produced: 1. anti-gentamicin antibody, 2. anti-ECDI antibody, 3. goat erythrocyte agglutinins. The interfering anti-ECDI antibody was easily neutralized by adding acidified ECDI solution to the immune serum. Goat agglutinins were avoided by employing rabbit erythrocytes as the carrier cell in the hemagglutination titration. Highly specific anti-gentamicin antiserum was produced in rabbits by first injecting an initial dose of gentamicin-BSA conjugate as an emulsion in incomplete Freund's adjuvant via the foot pad, followed by multiple intravenous injections of gentamicin-erythrocyte conjugates. The immunization took approximately 21 days. High titered anti-gentamicin antibody was also produced by foot pad inoculation of gentamicin-BSA conjugates; however, the time necessary to achieve comparable titers was considerably longer (55 days). The antibodies produced by both immunization procedures were mainly of the IgG class.