Detection of changes of the optic disc in glaucomatous eyes:Clinical examination and image analysis with the Topcon Imagenet system

Purpose: This study was designed to evaluate the clinical agreement in the detection of optic disc changes and the ability of computerized image analysis to detect glaucomatous deterioration of the optic disc. Methods: Pairs of stereophotographs of 35 glaucomatous optic discs taken 5 years apart and of 5 glaucomatous discs photographed twice on the same day. Two glaucoma specialists examined the pairs of stereophotographs (35 cases and 5 controls) in a masked manner and judged whether the optic disc showed changes in the optic disc compatible with progression of glaucomatous damage. The stereophotographs of the five optic discs photographed twice on the same day (which by definition did not change) and of five cases judged to have deteriorated by both glaucoma specialists were analyzed by computerized image analysis with the Topcon ImageNet system. Intra- and inter-observer agreement in the detection of optic disc changes (evaluated using kappa statistic), and changes in the rim area to disc area ratio (evaluated using descriptive statistics and paired t-test). Results: Intra-observer agreement had a kappa value of 0.75 for observer 1 and 0.60 for the observer 2. Inter-observer agreement between the glaucoma specialists had a kappa value of 0.60. The image analyzer did not discriminate between controls and cases with clinically apparent glaucomatous change of the optic disc. Conclusion: Clinical agreement in detecting changes in the optic disc was moderate to substantial. Computerized image analysis with the Topcon ImageNet system appeared not to be useful in detecting glaucomatous changes of the optic disc.

An Examination of Transformation Techniques to Investigate and Interpret Multivariate Geochemical Data Analysis: Tellus Case Study

This research aims to use the multivariate geochemical dataset, generated by the Tellus project, to investigate the appropriate use of transformation methods to maintain the integrity of geochemical data and inherent constrained behaviour in multivariate relationships. The widely used normal score transform is compared with the use of a stepwise conditional transform technique. The Tellus Project, managed by GSNI and funded by the Department of Enterprise Trade and Development and the EU’s Building Sustainable Prosperity Fund, involves the most comprehensive geological mapping project ever undertaken in Northern Ireland. Previous study has demonstrated spatial variability in the Tellus data but geostatistical analysis and interpretation of the datasets requires use of an appropriate methodology that reproduces the inherently complex multivariate relations. Previous investigation of the Tellus geochemical data has included use of Gaussian-based techniques. However, earth science variables are rarely Gaussian, hence transformation of data is integral to the approach. The multivariate geochemical dataset generated by the Tellus project provides an opportunity to investigate the appropriate use of transformation methods, as required for Gaussian-based geostatistical analysis. In particular, the stepwise conditional transform is investigated and developed for the geochemical datasets obtained as part of the Tellus project. The transform is applied to four variables in a bivariate nested fashion due to the limited availability of data. Simulation of these transformed variables is then carried out, along with a corresponding back transformation to original units. Results show that the stepwise transform is successful in reproducing both univariate statistics and the complex bivariate relations exhibited by the data. Greater fidelity to multivariate relationships will improve uncertainty models, which are required for consequent geological, environmental and economic inferences.

Potassium canrenoate treatment in paediatric patients: a population pharmacokinetic study using novel dried blood spot sampling

Objective: To characterize the population pharmacokinetics of canrenone following administration of potassium canrenoate (K-canrenoate) in paediatric patients.

Methods: Data were collected prospectively from 37 paediatric patients (median weight 2.9?kg, age range 2 days–0.85 years) who received intravenous K-canrenoate for management of retained fluids, for example in heart failure and chronic lung disease. Dried blood spot (DBS) samples (n?=?213) from these were analysed for canrenone content and the data subjected to pharmacokinetic analysis using nonlinear mixed-effects modelling. Another group of patients (n?=?16) who had 71 matching plasma and DBS samples was analysed separately to compare canrenone pharmacokinetic parameters obtained using the two different matrices.

Results: A one-compartment model best described the DBS data. Significant covariates were weight, postmenstrual age (PMA) and gestational age. The final population models for canrenone clearance (CL/F) and volume of distribution (V/F) in DBS were CL/F (l/h)?=?12.86?×? (WT/70.0)0.75?×?e [0.066?×? (PMA?-?40]) and V/F (l)?=?603.30?×? (WT/70)?×?(GA/40)1.89 where weight is in kilograms. The corresponding values of CL/F and V/F in a patient with a median weight of 2.9?kg are 1.11?l/h and 20.48?l, respectively. Estimated half-life of canrenone based on DBS concentrations was similar to that based on matched plasma concentrations (19.99 and 19.37?h, respectively, in 70?kg patient).

Conclusion: The range of estimated CL/F in DBS for the study population was 0.12–9.62?l/h; hence, bodyweight-based dosage adjustment of K-canrenoate appears necessary. However, a dosing scheme that takes into consideration both weight and age (PMA/gestational age) of paediatric patients seems more appropriate.

Development of an objective structured clinical examination (OSCE) to assess formulation and extemporaneous dispensing skills in MPharm undergraduates

Background: The use of Objective Structured Clinical Examination (OSCE) in Pharmacy has been explored; however this is the first attempt in Queen’s University School of Pharmacy, Belfast to assess students via this method in a module where chemistry is the main discipline.

Aims: To devise an OSCE to assess undergraduate ability to check extemporaneously dispensed products for clinical and formulation errors. This activity also aims to consider whether it is a viable method of assessment in such a science-based class, from a staff and student perspective.

Method: Students rotated around a number of stations, performing a check of the product, corresponding prescription and formulation record sheet detailing the theory behind the formulation. They were assessed on their ability to spot intentional mistakes at each one.

Results: Of the 79 students questioned, 95% indicated that OSCE made them aware of the importance of the clinical check carried out by the pharmacist. Nearly all of the undergraduates (72 out of 79) felt that OSCE made them aware of the type of mistakes that students make in class. Most (5 out of 7) of the academic team members strongly agreed that it made students aware of ‘point of dispensing’ checks carried out by pharmacists, in addition to helping them to prepare for their exam.

Conclusion: OSCE assesses both scientific and formulation skills, and has increased the diversity of assessment of this module, bringing with it many additional benefits for the undergraduates since it measures their ability to exercise professional judgement in a time- constrained environment and, in this way, mirrors the conditions many pharmacists work within.

Peer injecting: implications for injecting order and blood-borne viruses among men and women who inject heroin

A large body of research has highlighted practices and rituals that characterise injecting drug use and behavioural and environmental risks that can contribute to the transmission of blood-borne viruses. Compared with other injecting practices, considerably less is known about peer injecting, i.e. receiving or giving injections, particularly the social context in which it occurs. In this article, we explore peer injecting and injecting order at initiation into injecting drug user (IDU) and during subsequent injection episodes. Using data from semi-structured interviews, we highlight the experiences of 41 males and females who had received injections from other IDUs. Respondents were recruited through various strategies, largely chain referral. The results suggest gendered similarities as well as differences in terms of peer injecting, the order of injection and micro-risk contexts for blood-borne viruses. © 2013 Informa UK Ltd.

Polyamine system in developing rat eye and an animal model of retinopathy of prematurity

BACKGROUND: In experimental models of retinopathy of prematurity (ROP), a vasoproliferative disorder of the retina, retinal lesions are usually assessed by morphological examination. However, studies suggest that the polyamine system may be useful in monitoring proliferation processes. For this reason, polyamine concentrations in rat erythrocytes (RBC) and the regulation of polyamine system in rat eyes under the conditions relevant to ROP were investigated. METHODS: Newborn Wistar rats were reared in room air (control) or exposed first to hyperoxia (60% or 80% oxygen, 2 weeks) and then to normoxia (relative hypoxia, 1 or 2 weeks). Blood was collected from orbital vessels at 2 weeks of age and before death. Polyamine system-related enzyme activities were measured in retina and lens with radioassays. Polyamines were quantified by fluorometry after extraction, dansylation and HPLC separation. RESULTS: Oxygen (80% only) significantly decreased RBC polyamine concentrations, which then markedly increased after rats were transferred for a week to normal air, suggesting retardation of growth processes and compensatory stimulation, respectively. However, polyamine system changes in the rat eye were not so pronounced. Enzyme activities and polyamine concentrations tended to be lower in retina after hyperoxia and were only slightly higher, with the exception of ornithine decarboxylase, after a subsequent 1 week of normoxia. In litters subjected to normoxia for longer periods no changes were found. CONCLUSION: The transient and short-lived alteration in polyamine metabolism, especially in the eye, suggests that exposure of newborn rats to high oxygen supplementation followed by normoxia does not necessarily result in marked retinopathy.

Morphologic fluorescein angiographic, and light microscopic features of experimental choroidal neovascularization

We induced choroidal neovascularization in the rhesus monkey by impoverishing the blood supply to the inner retina and producing defects in Bruch's membrane by photocoagulation. Fourteen of 46 eyes undergoing photocoagulation developed neovascular fronds which were identified and categorized by histopathologic examination and fluorescein angiography. All new vessels gained access to the retina through defects in Bruch's membrane at the site of photocoagulation marks. In eight eyes the new vessels remained localized to the immediate vicinity of photocoagulation marks. In four eyes neovascular fronds infiltrated the subretinal space for distances up to 6 disk diameters from the point of entry into the retina. In the two eyes choroidovitreal neovascular complexes developed but rapidly regressed shortly after gaining the vitreous cavity. Fluorescein angiography demonstrated that all neovascular fronds were grossly incompetent to dye but that formed feeding channels had some degree of integrity. Light microscopic studies showed the proliferating networks to be composed of capillaries with well-formed basement membranes and more mature vessels with the basic structure of choroidal arteries and veins.

The sympathetic release test: a test used to assess thermoregulation and autonomic control of blood flow

When a subject is heated, the stimulation of temperature-sensitive nerve endings in the skin, and the raising of the central body temperature, results in the reflex release of sympathetic vasoconstrictor tone in the skin of the extremities, causing a measurable temperature increase at the site of release. In the sympathetic release test, the subject is gently heated by placing the feet and calves in a commercially available foot warming pouch or immersing the feet and calves in warm water and wrapping the subject in blankets. Skin blood flow is estimated from measurements of skin temperature in the fingers. Normally skin temperature of the fingers is 65-75 degrees F in cool conditions (environmental temperature: 59-68 degrees F) and rises to 85-95 degrees F during body heating. Deviations in this pattern may mean that there is abnormal sympathetic vasoconstrictor control of skin blood flow. Abnormal skin blood flow can substantially impair an individual's ability to thermoregulate and has important clinical implications. During whole body heating, the skin temperature from three different skin sites is monitored and oral temperature is monitored as an index of core temperature. Students determine the fingertip temperature at which the reflex release of sympathetic activity occurs and its maximal attainment, which reflects the vasodilating capacity of this cutaneous vascular bed. Students should interpret typical sample data for certain clinical conditions (Raynaud's disease, peripheral vascular disease, and postsympathectomy) and explain why there may be altered skin blood flow in these disorders.

Triose phosphate isomerase from the blood fluke Schistosoma mansoni:Biochemical characterisation of a potential drug and vaccine target

The glycolytic enzyme triose phosphate isomerase from Schistosoma mansoni is a potential target for drugs and vaccines. Molecular modelling of the enzyme predicted that a Ser-Ala-Asp motif which is believed to be a helminth-specific epitope is exposed. The enzyme is dimeric (as judged by gel filtration and cross-linking), resistant to proteolysis and highly stable to thermal denaturation (melting temperature of 82.0°C). The steady-state kinetic parameters are high (Km for dihydroxyacetone phosphate is 0.51mM; Km for glyceraldehyde 3-phosphate is 1.1mM; kcat for dihydroxyacetone phosphate is 7800s(-1) and kcat for glyceraldehyde 3-phosphate is 6.9s(-1)).

Growth of human B cell colonies from peripheral blood of patients with systemic lupus erythematosus

Human B cell colonies were grown from peripheral blood of 12 patients with systemic lupus erythematosus (SLE) and from 12 healthy control subjects. The SLE group showed a large increase (p less than 0.001) in the number of colony forming cells (CFC) present in peripheral blood as compared with controls. The CFC were of the pre-B cell type. There was also a loss of OKT8+ cell inhibition of B cell colony growth in the SLE group compared with control subjects.

Role of nitric oxide in maintenance of basal oral tissue blood flow in anesthetized cats

Experiments were undertaken to determine if nitric oxide (NO) plays a role in regulation of basal blood flow in the oral cavity of pentobarbital anesthetized cats and, if so, to quantify this effect using dose-response relationships. Blood flow was continuously measured from the surface of the tongue and mandibular gingiva (laser-Doppler flowmetry) and from the lingual artery (ultrasonic flowmetry). Cardiovascular parameters also were recorded. Administration of the nonselective inhibitor of nitric oxide synthase (NOS), L-NAME (0.08-20 mg/kg i.v.), produced a dose-related increase of blood pressure associated with decreases of blood flow at all three measurement sites. Maximal blood flow depression of 50-60% was seen 30-60 min after administration of 1.25 mg/kg of L-NAME. D-NAME (1.25 mg/kg i.v.) was inactive at all sites. Subsequent administration of L-arginine partially reversed effects of L-NAME in the lingual artery and tongue, but not in the gingival circulation. The neuronally selective NOS inhibitor, 7-nitroindazole (7-NI, 30 mg/kg i.p.), was devoid of effect on any of the measured parameters. These results suggest that endothelial (but not neuronally derived) NO plays an important role in control of basal blood flow in oral tissues of the cat.

Validation study to compare effects of processing protocols on measured Nε_(carboxymethyl)lysine and Nε_(carboxyethyl)lysine in blood.

Epidemiological studies show that elevated plasma levels of advanced glycation end products (AGEs) are associated with diabetes, kidney disease, and heart disease. Thus AGEs have been used as disease progression markers. However, the effects of variations in biological sample processing procedures on the level of AGEs in plasma/serum samples have not been investigated. The objective of this investigation was to assess the effect of variations in blood sample collection on measured Ne_(carboxy-methyl)lysine (CML), the best characterised AGE, and its homolog, Ne_(carboxyethyl)lysine (CEL). The investigation examined the effect on CML and CEL of different blood collection tubes, inclusion of a stabilising cocktail, effect of freeze thaw cycles, different storage times and temperatures, and effects of delaying centrifugation on a pooled sample from healthy volunteers. CML and CEL were measured in extracted samples by ultra_performance liquid chromatography-tandem mass spectrometry. Median CML and CEL ranged from 0.132 to 0.140 mM/M lys and from 0.053 to 0.060 mM/M lys, respectively. No significant difference was shown CML or CEL in plasma/serum samples. Therefore samples collected as part of epidemiological studies that do not undergo specific sample treatment at collection are suitable for measuring CML and CEL.

Microscopic Examination of Biofilm Destruction by Atmospheric Pressure Plasma

Objective: The aim of this study is to examine microscopically the destruction of bacterial biofilms mediated by atmospheric pressure non-thermal plasma (APNTP) at cellular level as well as at the level of biofilm structure as a whole. Methods: 3-day old bacterial biofilms were grown on polycarbonate coupons in a dual channel flow cell and were treated with an in-housed designed atmospheric pressure non-thermal plasma jet for up to 4 minutes of exposure before being examined by both confocal laser scanning microscopy (CLSM), preceded by Live/Dead bacterial viability staining, and scanning electron microscopy (SEM). Results: Differential live/dead staining followed by confocal microscopy examination revealed that biofilm eradication by APNTP was mediated by varying levels of both cell killing and physical removal. Relative extent of each mechanism was dependent on plasma operating conditions, bacterial species, growth conditions and biofilm thickness. On the other hand, SEM examination of plasma-exposed biofilms revealed a series of morphological changes exhibited by biofilm cells ranging from increased roughness of cell surface to complete cell lysis. Conclusions: Interesting mechanistic insights have been revealed by microscopic examination of plasma-treated bacterial biofilms that, when coupled with more specific biochemical studies, will not only contribute significantly to our understanding of the mechanism of plasma mediated biofilm destruction but also will help in better application-guided development of this novel anti-biofilm approach.