An in vitro investigation of the cardiovascular effects of the 5-HT(4) receptor selective agonists, velusetrag and TD-8954

The 5-HT(4) receptor agonists, and gastrointestinal (GI) prokinetic agents, cisapride and tegaserod, lack selectivity for the 5-HT(4) receptor. Cisapride is a potent human ether-à-go-go-related gene (hERG) potassium channel inhibitor while cisapride and tegaserod have significant affinity for 5-HT(1) and 5-HT(2) receptor subtypes. Marketing of both compounds was discontinued due to cardiovascular concerns (cardiac arrhythmias with cisapride and ischemic events with tegaserod). The reported association of tegaserod with ischemia has been postulated to involve coronary artery constriction or augmentation of platelet aggregation. This in vitro study investigated the effects of two of the new generation of highly selective 5-HT(4) receptor agonists, velusetrag and TD-8954, on canine, porcine and human coronary artery tone, human platelet aggregation and hERG potassium channel conductance. No significant off-target actions of velusetrag or TD-8954 were identified in these, and prior, studies. While cisapride inhibited potently the hERG channel currents, tegaserod failed to affect platelet aggregation, and had only a small contractile effect on the canine coronary artery at high concentrations. Tegaserod inhibited the 5-HT-induced contractile response in the porcine coronary artery. New generation 5-HT(4) receptor agonists hold promise for the treatment of patients suffering from GI motility disorders with a reduced cardiovascular risk.

SIMS(DAIRY): a modelling framework to identify sustainable dairy farms in the UK. Framework description and test for organic systems and N fertiliser optimisation

Multiple demands are placed on farming systems today. Society, national legislation and market forces seek what could be seen as conflicting outcomes from our agricultural systems, e.g. food quality, affordable prices, a healthy environmental, consideration of animal welfare, biodiversity etc., Many of these demands, or desirable outcomes, are interrelated, so reaching one goal may often compromise another and, importantly, pose a risk to the economic viability of the farm. SIMS(DAIRY), a farm-scale model, was used to explore this complexity for dairy farm systems. SIMS(DAIRY) integrates existing approaches to simulate the effect of interactions between farm management, climate and soil characteristics on losses of nitrogen, phosphorus and carbon. The effects on farm profitability and attributes of biodiversity, milk quality, soil quality and animal welfare are also included. SIMS(DAIRY) can also be used to optimise fertiliser N. In this paper we discuss some limitations and strengths of using SIMS(DAIRY) compared to other modelling approaches and propose some potential improvements. Using the model we evaluated the sustainability of organic dairy systems compared with conventional dairy farms under non-optimised and optimised fertiliser N use. Model outputs showed for example, that organic dairy systems based on grass-clover swards and maize silage resulted in much smaller total GHG emissions per l of milk and slightly smaller losses of NO(3) leaching and NO(x) emissions per l of milk compared with the grassland/maize-based conventional systems. These differences were essentially because the conventional systems rely on indirect energy use for 'fixing' N compared with biological N fixation for the organic systems. SIMS(DAIRY) runs also showed some other potential benefits from the organic systems compared with conventional systems in terms of financial performance and soil quality and biodiversity scores. Optimisation of fertiliser N timings and rates showed a considerable scope to reduce the (GHG emissions per l milk too).

Cost effectiveness of nitrate leaching mitigation measures for grassland livestock systems at locations in England and Wales

As much as 60% of the nitrate in water in England is thought to derive from agriculture. Legislation aims to improve water quality by limiting nitrate concentration in surface and groundwaters to 50 mg l(-1). The UK Government responded to the requirements of the EC Nitrate Directive by delineating Nitrate Vulnerable Zones (NVZs) to cover 55% of England in 2002 and increased it to 70% in 2009. In this study we assessed the cost-effectiveness of measures for implementation in livestock systems to mitigate nitrate leaching in the UK. These estimates were prepared for a range of hypothetical farms representative of typical dairy, beef and sheep farms at different locations in England and Wales and for a list of mitigation measures identified to reduce leaching. The NGAUGE and NFixCycle models were used to estimate leaching from these systems. The costs of implementation of the mitigation measures were also assessed in order to evaluate the cost-effectiveness of these measures. In general, the most effective measures to reduce leaching for all systems were the ones that involved a reduction in stocking rates and grazing time, followed by those involving improvements in fertiliser and crop management. Only in the case of the dairy system was effectiveness affected by location of the farm. The costs for implementation in the sheep system were relatively low compared with beef and dairy systems. Implementation of some of the measures with high cost-effectiveness would need to be incentivised financially or with legislation due to the high costs involved.

Using qualitative research to improve tissue viability care

This article discusses how key qualitative studies investigating patient experiences can act as an indicator of quality and guide healthcare professionals in service development and evaluation in tissue viability. There is a wealth of information available to suggest that leg ulceration affects individuals' quality of life. Commissioners are requesting that clinicians demonstrate quality-based outcomes for patients with leg ulcers to improve care and service provision.

[Comparing specific disc findings of a European and a Bantu population]

BACKGROUND

Glaucoma is the main cause of irreversible blindness in the world. Because of the increasing mean age, glaucoma is expected to become more common in the developing countries. Besides tonometry and perimetry the appearance of the optic nerve head is a main part of glaucoma diagnosis. Ethnic differences have to be considered. This study compares the appearance of the optic nerve head between blacks and whites.

STUDY DESIGN

This is a retrospective analysis of 225 whites of a Swiss population and 1027 blacks of a Congolese population. Using a matched pairs technique 207 whites and 207 blacks were chosen, regarding age, sex, intraocular pressure and examined eye (right/left). The analysis of the optic nerve head was performed by using the "Heidelberg-Retina-Tomograph II" (HRT).

RESULTS

Among the 207 persons of both groups we found 116 females and 91 males. There were 103 right eyes and 104 left eyes examined. The mean age was 45.6 +/- 15.6 years. Compared with European population in the African population we found a greater disc area (2.56 vs. 1.81 mm(2)) as well as a greater cup area (0.65 vs. 0.41 mm(2)) and a greater rim area (1.91 vs. 1.40 mm(2)). Regarding the cup disc area ratio there was no significant difference between both populations found (Kinshasa: 0.24 vs. Basel: 0.21). Although there was no significant difference of the maximum cup depth of both groups we found a deeper mean cup depth in the African population. Furthermore, we found differences regarding the cup shape measure, the RNFL thickness and the height variation contour.

CONCLUSION

As already described in different studies, there are significant differences in the morphology of the optic nerve head between blacks and whites. Although blacks are expected to have a greater cup disc area ratio, this fact could not be proved in this study. As a new fact we found a different mean cup depth between Africans and Europeans, which might be explained by the different cup shape of both populations.

[The currently most common causes of childhood blindness in Kinshasa (d. R. Congo)]

BACKGROUND

90 % of blind children live in the developing world. Only limited data are available on the prevalence and causes of blindness.

PURPOSE AND METHODS

In order to identify the commonest causes of childhood blindness in the Democratic Republic of Congo, a study was conducted in 81 children (< 16 years old) attending schools for the blind in the capital city Kinshasa.

RESULTS

According to WHO criteria, 53 (65.4 %) of the 81 children were classifiable as blind (visual acuity < 3/60), 11 (13.6 %) as visually impaired (visual acuity < 1/18) and 17 (21.0 %) as not impaired. On anatomic and functional classifications the commonest causes of blindness were: corneal opacity/scarring (20.0 %), phthisis bulbi (15.2 %), refractive anomalies (11.0 %), optic nerve atrophy (9.0 %), retinal disorders (7.6 %), glaucoma/buphthalmos (7.6 %), cataract (6.9 %), microphthalmos (3.5 %), vitreous opacity (2.8 %) and aphakia (2.1 %). The aetiology of blindness could not be determined in most of the children. Trauma, measles in conjunction with vitamin A deficiency, and the use of traditional eye medications are presumed to be the commonest causes of corneal opacity/scarring and of resultant phthisis bulbi.

CONCLUSION

Childhood blindness would be potentially avoidable in 60 % of cases, either by surgery (for cataract [ 6.9 %]) or by preventive measures (corneal opacity/scarring, phthisis bulbi, glaucoma, refractive anomalies [ 53.0 %]).

Field performance of transgenic tall fescue (Festuca arundinacea Schreb.) plants and their progenies

Tall fescue (Festuca arundinacea Schreb.) is a hexaploid, outcrossing grass species widely used for forage and turf purposes. Transgenic tall fescue plants were generated by biolistic transformation of embryogenic cell suspension cultures that were derived from single genotypes of widely used cultivar Kentucky-31. Primary transgenics from two genotypes, their corresponding regenerants from the same genotypes and control seed-derived plants were transferred to the field and evaluated for 2 years. Progenies of these three classes of plants were obtained and evaluated together with seed-derived plants in a second field experiment. The agronomic characteristics evaluated were: heading date, anthesis date, height, growth habit, number of reproductive tillers, seed yield and biomass. The agronomic performance of the primary transgenics and regenerants was generally inferior to that of the seed-derived plants, with primary transgenics having fewer tillers and a lower seed yield. However, no major differences between the progenies of transgenics and the progenies of seed-derived plants were found for the agronomic traits evaluated. Primary transgenics and regenerants from the same genotype were more uniform than plants from seeds. Progenies of transgenics performed similarly to progenies of the regenerants. The addition of a selectable marker gene in the plant genome seems to have had little effect on the agronomic performance of the regenerated plants. No indication of weediness of the transgenic tall fescue plants was observed. Our results indicate that outcrossing grass plants generated through transgenic approaches can be incorporated into forage breeding programs.

Making multimedia work for you: a wound management CD-ROM

The interactive nature of a CD-ROM makes it a valuable learning aid. One London trust saw this potential and developed a wound management CD-ROM that caters for the varying educational needs of its multidisciplinary team.

Assignment of the horse grey coat colour gene to ECA25 using whole genome scanning

The dominant grey coat colour gene of horses has been mapped using a whole genome scanning approach. Samples from a large half-sibling pedigree of Thoroughbred horses were utilized in order to map the grey coat colour locus, G. Multiplex groups of microsatellite markers were developed and used to efficiently screen the horse genome at a resolution of approximately 22 cM, based on an estimated map length for the horse genome of 2720 cM. The grey gene was assigned to chromosome 25 (ECA25), one of the smaller acrocentric horse chromosomes. Based on the current state of knowledge of conserved synteny and coat colour genetics in other mammalian species, there are no obvious candidate genes for the grey gene in the region.

Radiosurgery using a stereotactic headframe system for irradiation of brain tumors in dogs

Radiation therapy of brain tumors in dogs typically involves administration of multiple fractions over several weeks. Fractionation is used to minimize damage to normal tissue. Radiosurgery uses multiple non-coplanar stereotactically focused beams of radiation in a series of arcs to deliver a single dose to the target with extreme accuracy. The large number of beams facilitates a high degree of conformation between the treatment area and the target tumor and allows for a steep dose gradient; the use of nonintersecting arcs minimizes exposure of normal tissue. Computed tomography with a stereotactic localizer secured to the skull allows generation of a 3-dimensional image of the target and provides accurate spatial coordinates for computerized treatment planning and delivery. Three dogs were treated with radiosurgery, using 1,000 to 1,500 cGy. A linear accelerator mounted on a rotating gantry was used to generate and deliver the radiation. Two dogs with meningiomas survived 227 and 56 weeks after radiosurgery. A dog with an oligodendroglioma survived 66 weeks. No complications were observed following the use of this technique.

2-Amino-6-arylsulfonylbenzonitriles as non-nucleoside reverse transcriptase inhibitors of HIV-1

A series of 2-amino-5-arylthiobenzonitriles (1) was found to be active against HIV-1. Structural modifications led to the sulfoxides (2) and sulfones (3). The sulfoxides generally showed antiviral activity against HIV-1 similar to that of 1. The sulfones, however, were the most potent series of analogues, a number having activity against HIV-1 in the nanomolar range. Structural-activity relationship (SAR) studies suggested that a meta substituent, particularly a meta methyl substituent, invariably increased antiviral activities. However, optimal antiviral activities were manifested by compounds where both meta groups in the arylsulfonyl moiety were substituted and one of the substituents was a methyl group. Such a disubstitution led to compounds 3v, 3w, 3x, and 3y having IC50 values against HIV-1 in the low nanomolar range. When gauged for their broad-spectrum antiviral activity against key non-nucleoside reverse transcriptase inhibitor (NNRTI) related mutants, all the di-meta-substituted sulfones 3u-z and the 2-naphthyl analogue 3ee generally showed single-digit nanomolar activity against the V106A and P236L strains and submicromolar to low nanomolar activity against strains E138K, V108I, and Y188C. However, they showed a lack of activity against the K103N and Y181C mutant viruses. The elucidation of the X-ray crystal structure of the complex of 3v (739W94) in HIV-1 reverse transcriptase showed an overlap in the binding domain when compared with the complex of nevirapine in HIV-1 reverse transcriptase. The X-ray structure allowed for the rationalization of SAR data and potencies of the compounds against the mutants.