LTA4H rs2660845 association with montelukast response in early and late-onset asthma.

Leukotrienes play a central pathophysiological role in both paediatric and adult asthma. However, 35% to 78% of asthmatics do not respond to leukotriene inhibitors. In this study we tested the role of the LTA4H regulatory variant rs2660845 and age of asthma onset in response to montelukast in ethnically diverse populations. We identified and genotyped 3,594 asthma patients treated with montelukast (2,514 late-onset and 1,080 early-onset) from seven cohorts (UKBiobank, GoSHARE, BREATHE, Tayside RCT, PAGES, GALA II and SAGE). Individuals under montelukast treatment experiencing at least one exacerbation in a 12-month period were compared against individuals with no exacerbation, using logistic regression for each cohort and meta-analysis. While no significant association was found with European late-onset subjects, a meta-analysis of 523 early-onset individuals from European ancestry demonstrated the odds of experiencing asthma exacerbations by carriers of at least one G allele, despite montelukast treatment, were increased (odds-ratio = 2.92, 95%confidence interval (CI): 1.04-8.18, I2 = 62%, p = 0.0412) compared to those in the AA group. When meta-analysing with other ethnic groups, no significant increased risk of asthma exacerbations was found (OR = 1.60, 95% CI: 0.61-4.19, I2 = 85%, p = 0.342). Our study demonstrates that genetic variation in LTA4H, together with timing of asthma onset, may contribute to variability in montelukast response. European individuals with early-onset (≤18y) carrying at least one copy of rs2660845 have increased odd of exacerbation under montelukast treatment, presumably due to the up-regulation of LTA4H activity. These findings support a precision medicine approach for the treatment of asthma with montelukast.

Screening of the MMV and GSK open access chemical boxes using a viability assay developed against the kinetoplastid Crithidia fasciculata.

Diseases caused by the pathogenic kinetoplastids continue to incapacitate and kill hundreds of thousands of people annually throughout the tropics and sub-tropics. Unfortunately, in the countries where these neglected diseases occur, financial obstacles to drug discovery and technical limitations associated with biochemical studies impede the development of new, safe, easy to administer and effective drugs. Here we report the development and optimisation of a Crithidia fasciculata resazurin viability assay, which is subsequently used for screening and identification of anti-crithidial compounds in the MMV and GSK open access chemical boxes. The screening assay had an average Z' factor of 0.7 and tolerated a maximum dimethyl sulfoxide concentration of up to 0.5%. We identified from multiple chemical boxes two compound series exhibiting nanomolar potency against C. fasciculata, one centred around a 5-nitrofuran-2-yl scaffold, a well-known moiety in several existing anti-infectives, and another involving a 2-(pyridin-2-yl) pyrimidin-4-amine scaffold which seems to have pan-kinetoplastid activity. This work facilitates the future use of C. fasciculata as a non-pathogenic and inexpensive biological resource to identify mode of action/protein target(s) of potentially pan-trypanocidal potent compounds. This knowledge will aid in the development of new treatments for African sleeping sickness, Chagas disease and leishmaniasis.

An evaluation of the adhesion of solid oral dosage form coatings to the oesophagus.

There is a requirement for the development of oral dosage forms that are adhesive and allow extended oesophageal residence time for localised therapies, or are non-adhesive for ease of swallowing. This study provides an initial assessment of the in vitro oesophageal retention characteristics of several widely utilised pharmaceutical coating materials. To this end, a previously described apparatus has been used to measure the force required to pull a coated disc-shaped model tablet across a section of excised oesophageal tissue. Of the materials tested, the well-studied mucoadhesive polymer sodium alginate was found to be associated with significant oesophageal adhesion properties that was capable of 'self-repairing'. Hydroxypropylmethylcellulose exhibited less pronounced bioadhesive behaviour and blending this with plasticiser or with low molecular weight polymers and surfactants did not significantly affect this. Low molecular weight water soluble polymers, were found to behave similarly to the uncoated glass control disc. Polysorbates exhibited bioadhesion behaviour that was majorly influenced by the nature of the surfactant. The insoluble polymer ethylcellulose, and the relatively lipophilic surfactant sorbitan monooleate were seen to move more readily than the uncoated disc, suggesting that these may have a role as 'easy-to-swallow' coatings.

The influence of light administration on interpersonal behavior and affect in people with mild to moderate seasonality.

Bright light is used to treat winter depression and may also have positive effects on mood in some healthy individuals. However, there is little information on how bright light treatment influences social behavior. We performed a cross-over study in winter comparing the effects of morning bright light administration with placebo (exposure to negative ions) on mood and social behavior in 38 healthy people with mild to moderate seasonality. Each treatment was given for 21days with a washout period of 14days between treatments. An event-contingent recording assessment was used to measure mood, and social behavior along two axes, agreeable-quarrelsome and dominant-submissive, during each 21-day treatment period. During treatments, participants wore a combined light-sensor and accelerometer to test this method for adherence to light treatment self-administered at home. Data were analyzed using multilevel modeling. Bright light improved mood but increased quarrelsome behavior and decreased submissiveness. Data from the light monitor and accelerometer suggested that 21% of the participants did not adhere to bright light treatment; when this group was analyzed separately, there was no change in quarrelsomeness or mood. However, results for individuals who followed the procedure were similar to those reported for the whole sample.

Recognizing emotions in faces: effects of acute tryptophan depletion and bright light.

In healthy never-depressed individuals, acute tryptophan depletion (ATD) may selectively decrease the accurate recognition of fearful facial expressions. Here we investigated the perception of facial emotions after ATD in more detail. We also investigated whether bright light, which can reverse ATD's mood-lowering effect, can also reverse its effect on the perception of facial emotions. On two separate test days, spent in a room that was either bright (n = 14) or dim (n = 16), healthy never-depressed women completed a facial emotion perception task six hours after ingesting tryptophan-deficient and balanced amino acid mixtures. Treatments were administered double blind and in randomized order using a crossover design. In dim light ATD decreased recognition accuracy of anger, disgust, and surprise. The labeling of fear and sadness was not affected. In bright light no effects of ATD were seen. Bright light was identified as a potential confounding factor in task performance. The effects of ATD on facial emotion perception may be less emotion-specific than thought previously, and occurred in a direction opposite to what might be expected based on theories of mood-congruent bias.

Combined functional MRI and diffusion tensor imaging analysis of visual motion pathways.

BACKGROUND: Motion perception may be preserved after damage to striate cortex (primary visual cortex, area V1). Awareness and normal discrimination of fast-moving stimuli have been observed even in the complete absence of V1. These facts suggest that motion-sensitive cortex (the V5/MT complex or V5/MT+) may be activated by direct thalamic or collicular inputs that bypass V1. Such projections have been identified previously in monkeys but have not been shown in humans using neuroimaging techniques. METHODS: We used diffusion tensor imaging (DTI) tractography to visualize white matter fiber tracts connecting with V5/MT+ in 10 healthy volunteers. V5/MT+ was localized for each subject using functional MRI (fMRI). Functional activity maps were overlaid on high-resolution anatomical images and registered with the diffusion-weighted images to define V5/MT+ as the region of interest (ROI) for DTI tractography analysis. Fibers connecting to V1 were excluded from the analysis. RESULTS: Using conservative tractography parameters, we found connections between the V5/MT+ region and the posterior thalamus and/or superior colliculus in 4 of 10 subjects. CONCLUSIONS: Connections between the V5/MT+ region and the posterior thalamus and/or superior colliculus may explain visual motion awareness in the absence of a functioning V1.

Bright light exposure during acute tryptophan depletion prevents a lowering of mood in mildly seasonal women.

We investigated the influence of bright light exposure on the mood-lowering effect of acute tryptophan depletion (ATD). Mildly seasonal healthy young women without a personal or family history of psychiatric disorders remained in either dim or bright light during two test days. Tryptophan-deficient and nutritionally balanced amino acid mixtures were administered in counterbalanced order. Mood state was assessed using the Profile of Mood States (POMS) and Visual Analogue Scales (VAS). In dim light, ATD decreased POMS scores across most subscales, indicating a worsening of mood. In bright light, mood was unaffected by ATD. Thus, bright light blocked the worsening of mood caused by ATD. This was also observed on the positive mood VAS. These results indicate a direct, immediate interaction between bright light and serotonin function. Bright light might help protect against ATD-induced mood change by increasing serotonin above the threshold level below which there is a lowering of mood.

Glucose enhances newborn memory for spoken words.

The effect of a 2 g/kg glucose feed was compared with a water feed on retention of a spoken word in 2-4 days old infants in a between group randomized trial. Infants heard a word in 30-s trials until they demonstrated orientation (head turns towards the sound) and habituation. After a 100 s delay, infants who received glucose turned toward the word less often than infants receiving water (means 31.8 vs. 57.7%, t = 2.8, p < 0.01) implying that they remembered the word better. There were no differences between groups in measures of attention to or rate of learning of the word. Only infants who subsequently oriented towards a different word, indicating that they remained alert, were used in the data analysis. The results suggest that glucose enhanced memory for a spoken word in neonates.

10. Bruising, abrasions and lacerations: minor injuries in children I.

Minor injuries in children (those that could reasonably be expected to heal with minimal medical intervention) are extremely common. The possibility of more serious injuries should be considered and excluded early. Successful examination requires gaining the child's trust, relieving pain early, and using a flexible and creative examination technique. Bruising may suggest a more serious underlying injury, or the bruising pattern may indicate non-accidental injury or a bleeding disorder. Superficial abrasions and lacerations can be safely cleaned with good quality water, and all foreign material should be removed. Deeper wounds with suspected damage to nerves, tendons or circulation need formal exploration under a general anaesthetic. Good local anaesthesia can be produced by topical preparations, and many wounds can be closed with tissue adhesives with an excellent cosmetic result. Antibiotics should be prescribed for specific circumstances, such as wounds with extensive contamination or tissue damage, and all children with injuries should be checked for adequate tetanus cover for prophylaxis.

Polymeric microspheres for drug delivery to the oral cavity: an in vitro evaluation of mucoadhesive potential.

Polymeric microparticles were fabricated from Carbopol, polycarbophil, chitosan, or Gantrez using a "water-in-oil emulsification" solvent evaporation method. Mean particle sizes, as determined by laser diffraction, were in the range 23-38 microm. Electron microscopy revealed that all microparticles were spherical and of smooth surface morphology. In pH 7.0 phosphate buffered saline, the microspheres exhibited significantly increased swelling ratios and longer half-times of swelling than the corresponding powdered polymers. The relative merits of the potential usefulness of these microspheres as formulation tools for the enhanced retention of a therapeutic entity within the oral mucosa were evaluated by in vitro mucoadhesion tests. Tensile tests showed that all microspheres under consideration were capable of adhering to porcine esophageal mucosa, with particles prepared from the poly(acrylic acid)s exhibiting greater mucoadhesive strength than those constructed from chitosan or Gantrez. However, in elution experiments involving a challenge with artificial saliva, particles of chitosan or Gantrez were retained onto mucosal tissue for longer time periods than those assembled from the poly(acrylic acid)s.

An in vitro model for investigating the gastric mucosal retention of 14C-labelled poly(acrylic acid) dispersions.

Polymers that bind from solution onto gastric mucosae can be used as a means of facilitating localised drug delivery, or act as therapeutic agents in their own right (e.g. by forming a protective layer or by inhibiting enzymes). Previous workers have used semi-quantitative methods to identify the ability of commercially available poly(acrylic acid)s to bind to gastric mucosa. In this study, the binding and retention of labelled poly(acrylic acid)s to sections of gastric mucosa from the pyloric region of pigs stomach were evaluated using 'static' and 'dynamic flow' test systems. Dispersions (3%) of 'low', 'high' and 'ultra high' (cross-linked) polymers were seen to adhere to porcine pyloric mucosa after exposure and rinsing in the 'static' system. The high molecular weight polymer showed the greatest retention in the 'dynamic' test system when washing continuously with simulated gastric acid. Changing the pH of the dispersions from 4.3 to 6.2 had little effect on polymer retention. It was concluded that polymers that were sufficiently mobile in solution to spread on, and interact with, the mucosal surface, but had a sufficiently high molecular weight to form viscous solutions and/or bioadhere to the mucosa, may be retained on the mucosal surface for the longest periods.

Characterization of nasal obstruction in the allergic guinea pig using the forced oscillation method.

INTRODUCTION: This is the first report to evaluate changes in nasal resistance in a preclinical animal model using the forced oscillation method. METHODS: The method involves characterizing pressure-flow relationships of the respiratory system due to external oscillatory forces. RESULTS: First, we evaluated changes in nasal resistance using an established small-animal rhinometric technique. In these studies, aerosolized ovalbumin (3%) administered to the nasal cavity of ovalbumin-sensitized guinea pigs increased nasal resistance at 30 min by 99 +/- 14%. The histamine H1 antagonists, chlorpheniramine (1 mg/kg i.v.) and pyrilamine (1 mg/kg i.v.), blocked the increase in nasal resistance due to ovalbumin provocation (50 +/- 17% and 39 +/- 11% over baseline, respectively). The alpha-adrenergic agonist phenylpropanolamine (3 mg/ kg i.v.) had no effect on the nasal actions of ovalbumin. In separate studies, nasal resistance was measured at 2 Hz by forced oscillation and ovalbumin (3%) increased nasal resistance by 91 +/- 14%. Chlorpheniramine (1 mg/kg i.v.) significantly attenuated the increase in nasal resistance due to ovalbumin. Finally, changes in nasal resistance for each treatment group were evaluated at frequencies of 1 - 18 Hz. Area under the curve analysis demonstrated that chlorpheniramine blocked the nasal obstructive effect of ovalbumin. In contrast, a pharmacologically active dose of phenylpropanolamine (3 mg/kg i.v.) did not produce decongestant activity. DISCUSSION: The current data are inconsistent with the well-established clinical efficacy of alpha-adrenergic agonists as nasal decongestants. Consequently, we suggest that allergic nasal obstruction in the guinea pig may not be the best preclinical approach to assess the nasal decongestant activity of vasoconstrictor alpha-adrenergic agonists. Additionally, our studies demonstrate the utility of the forced oscillation technique in assessing changes in nasal resistance in small laboratory animals.