Dried blood spot liquid chromatography assay for therapeutic drug monitoring of metformin

The use of blood spot collection cards is a simple way to obtain specimens for analysis of drugs for the purpose of therapeutic drug monitoring, assessing adherence to medications and preventing toxicity in routine clinical setting. We describe the development and validation of a microanalytical technique for the determination of metformin from dried blood spots. The method is based on reversed phase high-performance liquid chromatography with ultraviolet detection. Drug recovery in the developed method was found to be more than 84%. The limits of detection and quantification were calculated to be to be 90 and 150 ng/ml, respectively. The intraday and interday precision (measured by CV%) was always less than 9%. The accuracy (measured by relative error, %) was always less than 12%. Stability analysis showed that metformin is stable for at least 2 months when stored at -70 degrees C. The small volume of blood required (10 mu L), combined with the simplicity of the analytical technique makes this a useful procedure for monitoring metformin concentrations in routine clinical settings. The method is currently being applied to the analysis of blood spots taken from diabetic patients to assess adherence to medications and relationship between metformin level and metabolic control of diabetes. (c) 2006 Elsevier B.V. All rights reserved.

Prospective strategies underlie the control of interceptive actions.

The purpose of this study was to test whether a constant bearing angle strategy could account for the displacement regulations produced by a moving observer when attempting to intercept a ball following a curvilinear path. The participants were asked to walk through a virtual environment and to change, if (deemed) necessary, their walking speed so as to intercept a moving ball that followed either a rectilinear or a curvilinear path. The results showed that ball path curvature did indeed influence the participants' displacement kinematics in a way that was predicted by adherence to a constant bearing angle strategy mode of control. Velocity modifications were found to be proportional to the magnitude of target curvature with opposing curvatures giving rise to mirror displacement velocity changes. The role of prospective strategies in the control of interceptive action is discussed

Development and validation of an HPLC method for the rapid and simultaneous determination of 6-mercaptopurine and four of its metabolites in plasma and red blood cells

An HPLC method has been developed and validated for the rapid determination of mercaptopurine and four of its metabolites; thioguanine, thiouric acid, thioxanthine and methylmercaptopurine in plasma and red blood cells. The method involves a simple treatment procedure based on deproteinisation by perchloric acid followed by acid hydrolysis and heating for 45 min at 100 degrees C. The developed method was linear over the concentration range studied with a correlation coefficient >0.994 for all compounds in both plasma and erythrocytes. The lower limits of quantification were 13, 14, 3, 2, 95 pmol/8 x 101 RBCs and 2, 5, 2, 3, 20 ng/ml plasma for thioguanine, thiouric acid, mercaptopurine, thioxanthine and methylmercaptopurine, respectively. The method described is selective and sensitive enough to analyse the different metabolites in a single run under isocratic conditions. Furthermore, it has been shown to be applicable for monitoring these metabolites in paediatric patients due to the low volume requirement (200 mu l of plasma or erythrocytes) and has been successfully applied for investigating population pharmacokinetics, pharmacogenetics and non-adherence to therapy in these patients. (C) 2008 Elsevier B.V. All rights reserved.

Persistence of antimicrobial activity through sustained release of triclosan from pegylated silicone elastomers

Microbial adhesion to silicone elastomer biomaterials is a major problem often resulting in infection and medical device failure. Several strategies have been employed to modulate eukaryotic cell adhesion and to hamper bacterial adherence to polymeric biomaterials. Chemical modification of the surface by grafting of polyethylene glycol (PEG) chains or the incorporation of non-antibiotic antimicrobial agents such as triclosan into the biomaterial matrix may reduce bacterial adhesion. Here, such strategies are simultaneously applied to the preparation of both condensation-cure and addition-cure silicone elastomer systems, seeking a sustained release antimicrobial device biomaterial. The influence of triclosan incorporation and degree of pegylation on antimicrobial release, surface microbial adherence and persistence (Escherichia coli and Staphylococcus epidermidis) were evaluated in vitro. Non-pegylated silicone elastomers provided an increased percentage release of triclosan extending over a relatively short duration (99% release by day 64) compared with their pegylated (4% w/w) counterparts (65% and 72% release by day 64, for condensation and addition-cure systems respectively). Viable E. coli adherence to a non-pegylated silicone elastomer containing 1% w/w triclosan was reduced by over 99% after 24 h compared to the non-pegylated silicone elastomer containing no triclosan. No viable S. epidermidis adhered to any of the triclosan-loaded (>0.1% w/w) formulations other than the control. Persistence of the antimicrobial activity of the triclosan-loaded pegylated silicone elastomers continued for at least 70 days compared to the triclosan-loaded non-pegylated elastomers (at least 49 days). Understanding how PEG affects the release of triclosan from silicone elastomers may prove useful in the development of a biomaterial providing prolonged, effective antimicrobial activity.

The prevalence of nonadherence in difficult asthma

Rationale: With the advent of new and expensive therapies for severe refractory asthma, targeting the appropriate patients is important. An important issue is identifying nonadherence with current therapies. The extent of nonadherence in a population with difficult asthma has not been previously reported.

Objectives: To examine the prevalence of nonadherence to corticosteroid medication in a population with difficult asthma referred to a Specialist Clinic and to examine the relationship of poor adherence to asthma outcome.

Methods: General practitioner prescription refill records for the previous 6 months for inhaled combination therapy and short-acting ß-agonists were compared with initial prescriptions and expressed as a percentage. Blood plasma prednisolone and cortisol assay levels were used to examine the utility of these measures in assessing adherence to oral prednisolone. Patient demographics, hospital admissions, lung function, oral prednisolone courses, and quality of life data were analyzed to indentify the variables associated with reduced medication adherence.

Measurements and Main Results: A total of 182 patients were assessed. Sixty-three patients (35%) filled 50% or fewer inhaled medication prescriptions; 88% admitted poor adherence with inhaled therapy after initial denial. Twenty-one percent of patients filled more than 100% of presciptions, and 45% of subjects filled between 51 and 100% of prescriptions. Twenty-three of 51 patients (45%) prescribed oral steroids were found to be nonadherent.

Conclusions: A significant proportion of patients with difficult-to-control asthma remained nonadherent to corticosteroid therapy. Objective surrogate and direct measures of adherence should be performed as part of a difficult asthma assessment and are important before prescibing expensive novel biological therapies.

‘Doing it with men’: feminist research practice and patriarchal inheritance practices in Welsh family farming

Internationally, the gender relations of the family farming ‘way of life’ have beenshown to be stubbornly persistent in their adherence to patriarchal inheritancepractices. This article demonstrates how such ‘agri-cultural’ practices are situated bothwithin the subjective sphere of farming individuals’ and within global agri-economics,bringing new challenges to patrilineal farm survival. It is suggested here that the recenttendency for post-structuralist theorisation in rural studies has underestimated theexistence and impact of patrilineal patterns in family farming. Such patterns mean thatwomen are shown to largely occupy relational gender identities as the ‘helper’, whilstmen are strongly identified as the ‘farmer’. Drawing on repeated life-history interviewsconducted with farming men and women from Powys, Mid Wales, the aim of thisarticle is to generate debate as to the extent to which men can be brought into feministresearch practice in order to reveal patriarchy to a greater degree. The article begins bysituating the near-exclusion of men from feminist research practice within theoreticaldevelopments in feminist geography. This discussion also assists in deriving issues ofresearch methods, positionality and interpretive power which focus the integration ofempirical material in the methodological reflections provided in section three. In sectiontwo, the rationale for the epistemological stance taken in the research is provided. Thearticle provides an example of the successful integration of men into a feminist researchframe, suggests avenues for theoretical development and identifies future researchdirections which can be informed by ‘doing it with men’.

Keywords: epistemology; family farming; feminist res

Revisioning assessment through a children’s rights approach: implications for policy, process and practice

The linkage between the impact of assessment and compliance with children’s rights is a connection, which although seemingly obvious, is nonetheless rarely made, particularly by governments, which, as signatories to the relevant human rights treaties, have the primary responsibility for ensuring that educational practice is compatible with international children’s rights standards. While some jurisdictions are explicit about an adherence to children’s rights frameworks in general policy documentation, such a commitment rarely features when the focus is on assessment and testing. Thus, in spite of significant public and academic attention given to the consequences of assessment for children and governments committed to working within children’s rights standards, the two are rarely considered together. This paper examines the implications for the policy, process and practice of assessment in light of international human rights standards. Three key children’s rights principles and standards are used as a critical lens to examine assessment policy and practice: (1) best interests; (2) non-discrimination; and (3) participation. The paper seeks new insights into the complexities of assessment practice from the critical perspective of children’s rights and argues that such standards not only provide a convenient benchmark for developing, implementing and evaluating assessment practices, but also acknowledge the significance of assessment in the delivery of children’s rights to, in and through education more generally.

Unconscious Vigilance: Worldview Defense without Adaptations for Terror, Coalition or Uncertainty Management

Individuals subtly reminded of death, coalitional challenges, or feelings of uncertainty display exaggerated preferences for affirmations and against criticisms of their cultural in-groups. Terror management, coalitional psychology, and uncertainty management theories postulate this “worldview defense” effectas the output of mechanisms evolved either to allay the fear of death, foster social support, or reduce anxiety by increasing adherence to cultural values. In 4 studies, we report evidence for an alternative perspective. We argue that worldview defense owes to unconscious vigilance, a state of accentuatedreactivity to affective targets (which need not relate to cultural worldviews) that follows detection of subtle alarm cues (which need not pertain to death, coalitional challenges, or uncertainty). In Studies 1 and 2, death-primed participants produced exaggerated ratings of worldview-neutral affective targets. In Studies 3 and 4, subliminal threat manipulations unrelated to death, coalitional challenges, or uncertaintyevoked worldview defense. These results are discussed as they inform evolutionary interpretations of worldview defense and future investigations of the influence of unconscious alarm on judgment.

Changing profile in the use of anti-asthma drugs

Data regarding the total number of anti-asthma drugs dispensed via community pharmacies within Northern Ireland from 1980 to 1997 were collected and analysed. The use of anti-asthma drugs within this population increased markedly over the study period from 19.84 DDDs/1000/day to 84.07 DDDs/1000/day. With the exception of the non-selective beta(2)-agonists, there has been an overall increasing trend in the utilization of all of the anti-asthma drugs during the study period. Most of the increase is attributable to the increase in prescribing of the selective beta(2)-agonists and the glucocorticoids, This increase in the utilization of anti-asthma drugs may be explained by an increasing prevalence of the condition, increased adherence to asthma management protocols or to the prescribing of more intensive drug therapies.

Standardisation and comparison of methods employed for microbial cell surface hydrophobicity and charge determination

Whilst there are a number of methods available to characterise the cell surface hydrophobicity (CSH) and cell surface charge (CSC) of microorganisms, there is still debate concerning the correlation of results between individual methods. In this study, the techniques of bacterial adherence to hydrocarbons (BATH) and hydrophobic interaction chromatography (HTC) were used to measure CSH. Electrostatic interaction chromatography (ESIC) and zeta potential (ZP) measurements were used to determine CSC. To allow meaningful comparisons between the BATH and HIC tests, between ESIC and ZP and also between CSH and CSC, the buffer systems employed in each test were standardised (phosphate buffered saline, pH 7.3, 0.01 mM). Isolates of Staphylococcus epidermidis derived from microbial biofilm were used as the test organism in this study. The isolates examined exhibited primarily medium to high CSH and a highly negative CSC. Good correlation of CSH measurement was observed between the BATH and HIC tests (r = 0.89). Good correlation was observed between ESIC (anionic exchange column) and ZP measurements. No correlations were observed between isolate CSC and either increased or decreased CSH. It is recommended that whenever comparisons of various methods to determine either CSC or CSH (by partitioning methods), the buffer systems should remain constant throughout to achieve consistency of results.

THE EFFECTS OF 3 NON-ANTIBIOTIC, ANTIMICROBIAL AGENTS ON THE SURFACE HYDROPHOBICITY OF CERTAIN MICROORGANISMS EVALUATED BY DIFFERENT METHODS

The effects of three non-antibiotic, antimicrobial agents (taurolidine, chlorhexidine acetate and providone-iodine) on the surface hydrophobicity of the clinical strains Escherichia coli, Staphylococcus saprophyticus, Staphylococcus epidermidis and Candida albicans were examined. Three recognized techniques for hydrophobicity measurements, Bacterial Adherence to Hydrocarbons (BATH), the Salt Aggregation Test (SAT) and Hydrophobic Interaction Chromatography (HIC) were compared. At concentrations reported to interfere with microbial-epithelial cell adherence, all three agents altered the cell surface hydrophobicity. However, these effects failed to exhibit a uniform relationship. Generally, taurolidine and povidone-iodine treatments decreased the hydrophobicity of the strains examined whereas chlorhexidine acetate effects depended upon the micro-organism treated. Subsequently, the exact contribution of altered cell surface hydrophobicity to the reported microbial anti-adherence effects is unclear. Comparison of the three techniques revealed a better correlation between the results obtained with the BATH test and HIC than the results obtained with the BATH and SAT or SAT and HIC. However, these differences may be due to the inaccuracy associated with the visual assessment of results employed by the SAT.

Dietary patterns and bone mineral status in young adults: the Northern Ireland Young Hearts Project

Studies of individual nutrients or foods have revealed much about dietary influences on bone. Multiple food or nutrient approaches, such as dietary pattern analysis, could offer further insight but research is limited and largely confined to older adults. We examined the relationship between dietary patterns, obtained by a posteriori and a priori methods, and bone mineral status (BMS; collective term for bone mineral content (BMC) and bone mineral density (BMD)) in young adults (20-25 years; n 489). Diet was assessed by 7 d diet history and BMD and BMC were determined at the lumbar spine and femoral neck (FN). A posteriori dietary patterns were derived using principal component analysis (PCA) and three a priori dietary quality scores were applied (dietary diversity score (DDS), nutritional risk score and Mediterranean diet score). For the PCA-derived dietary patterns, women in the top compared to the bottom fifth of the 'Nuts and Meat' pattern had greater FN BMD by 0.074 g/cm(2) (P=0.049) and FN BMC by 0.40 g (P=0.034) after adjustment for confounders. Similarly, men in the top compared to the bottom fifth of the 'Refined' pattern had lower FN BMC by 0.41 g (P-0.049). For the a priori DDS, women in the top compared to the bottom third had lower FN BMD by 0.05 g/cm(2) after adjustments (P=0.052), but no other relationships with BMS were identified. In conclusion, adherence to a 'Nuts and Meat' dietary pattern may be associated with greater BMS in young women and a 'Refined' dietary pattern may be detrimental for bone health in young men.

Different sugar residues of the lipopolysaccharide outer core are required for early interactions of Salmonella enterica serovars Typhi and Typhimurium with epithelial cells

The role of lipopolysaccharide (LPS) in entry of Salmonella Typhimurium into epithelial cells remains unclear. In this study, we tested the ability of a series of mutants with deletions in genes for the synthesis and assembly of the O antigen and the outer core of LPS to adhere to and invade HeLa, BHK, and IB3 epithelial cells lines. Mutants devoid of O antigen, or that synthesized only one O antigen unit, or with altered O antigen chain lengths were as able as the wild type to enter epithelial cells, indicating that this polysaccharide is not required for invasion of epithelial cells in vitro. In contrast, the LPS core plays a role in the interaction of S. Typhimurium with epithelial cells. The minimal core structure required for adherence and invasion comprised the inner core and residues Glc I Gal I of the outer core. A mutant of S. Typhimurium that produced a truncated LPS core lacking the terminal galactose residue had a significant lower level of adherence to and ingestion by the three epithelial cell lines than did strains with this characteristic. Complementation of the LPS production defect recovered invasion to parental levels. Heat-killed bacteria with a core composed of Glc 1 Gal I. but not bacteria with a core composed of Glc 1, inhibited uptake of the wild type by HeLa cells. A comparison of the chemical structure of the S. Typhi core with the published chemical structure of that of S. Typhimurium indicated that the Glc I Gal 1 Glc 11 backbone is conserved in both serovars. However, S. Typhi requires a terminal glucose for maximal invasion. Therefore, our data indicate that critical saccharide residues of the outer core play different roles in the early interactions of serovars Typhi and Typhimurium with epithelial cells. (C) 2010 Elsevier Ltd. All rights reserved.

Investigation of molecular markers in the diagnosis of refractory coeliac disease in a large patient cohort

Some patients with coeliac disease, despite strict adherence to a gluten-free diet, continue to have significant symptoms and/or a severe small intestinal histological lesion. The term "refractory coeliac disease" (rCD) is used to describe this condition. The purpose of this study was to investigate the value of tissue molecular markers reported to help in the diagnosis of rCD.

Nontypable Haemophilus influenzae displays a prevalent surface structure molecular pattern in clinical isolates

Non-typable Haemophilus influenzae (NTHi) is a gram negative pathogen that causes acute respiratory infections and is associated with the progression of chronic respiratory diseases. Previous studies have established the existence of a remarkable genetic variability among NTHi strains. In this study we show that, in spite of a high level of genetic heterogeneity, NTHi clinical isolates display a prevalent molecular feature, which could confer fitness during infectious processes. A total of 111 non-isogenic NTHi strains from an identical number of patients, isolated in two distinct geographical locations in the same period of time, were used to analyse nine genes encoding bacterial surface molecules, and revealed the existence of one highly prevalent molecular pattern (lgtF+, lic2A+, lic1D+, lic3A+, lic3B+, siaA-, lic2C+, ompP5+, oapA+) displayed by 94.6% of isolates. Such a genetic profile was associated with a higher bacterial resistance to serum mediated killing and enhanced adherence to human respiratory epithelial cells.