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Biomedical subjects

P Sanders

Publications and source records attributed to P Sanders.

At least 37 records · Page 2Linked to original sources
PubMed2001

Phased-Array intracardiac echocardiography to guide radiofrequency ablation in the left atrium and at the pulmonary vein ostium.

INTRODUCTION: We sought to evaluate the utility of a phased-array intracardiac echocardiography (ICE) device to identify left atrial (LA) and pulmonary vein (PV) anatomy; accurately guide radiofrequency ablation (RFA) to the right or left PV ostium and LA appendage (LAA); and evaluate PV blood flow before and after RFA using Doppler parameters. METHODS AND RESULTS: Twelve adult sheep were anesthetized and an Acuson 10-French, 7-MHz ICE transducer introduced via the internal jugular vein into the right atrium. The LA was imaged and PV anatomy and blood flow documented using two-dimensional and pulsed-wave Doppler. Mean LA dimensions were 4.6 +/- 0.4 x 3.5 +/- 0.5 cm; mean single right and left main PV ostium diameters were 1.5 +/- 0.2 and 1.3 +/- 0.3 cm; and mean right and left PV first-order branch diameters were 0.8 +/-0.2 and 0.6 +/- 0.1 cm. Mean PV maximum inflow velocity for the right PV were 0.30 +/- 0.05 m/sec and for the left PV were 0.35 +/- 0.04 m/sec. The PV ostia and LAA could be targeted accurately for RFA using ICE guidance. At pathologic evaluation, the mean distance of the lesion center to the right or left PV-LA junction was 3.0 +/- 2.0 mm. The mean distance of the lesion center to the posterior margin of the LAA was <4 mm in all cases. There was no significant increase in PV maximum inflow velocity or decrease in PV diameter following RFA at the PV ostium. Absence of PV obstruction was confirmed at pathology. CONCLUSION: Phased-array ICE allows detailed assessment of LA and PV anatomy when imaged from the right atrium; accurate guidance of RFA to the PV ostium and LAA; and immediate evaluation of PV patency after RFA.

Animals↗
PubMed2001

Focal atrial tachycardia arising from the tricuspid annulus: electrophysiologic and electrocardiographic characteristics.

INTRODUCTION: Focal right atrial tachycardia (RAT) arising from the crista terminalis, para-Hisian, and coronary sinus os regions are well described. Less information exists regarding RAT arising from the nonseptal region of the tricuspid annulus (TA). METHODS AND RESULTS: From a consecutive series of 64 patients who had undergone successful radiofrequency ablation (RFA) of 67 RATs, the characteristics of 9 (13%) patients (6 men; mean age 50 +/- 20 years) with a TA focus were reviewed. The annular focus was localized to the inferoanterior TA in 7 and the superior TA in 2. Mean tachycardia cycle length was 371 +/- 66 msec. Mean activation time at the site of successful RFA in 9 of 9 patients was -43 +/- 11 msec. At 9.3 +/- 5.6 months of follow-up, 1 of 9 patients had recurrent tachycardia successfully treated with repeat RFA. In 7 of 9 patients with RAT from the inferoanterior TA, the surface ECG P wave morphology was upright in aVL, inverted in III and VI, and either inverted or biphasic with an initial negative deflection from V2 to V6. CONCLUSION: The TA is an important site of origin of RAT. In the present study, the inferoanterior region of the TA was a preferential site of origin with resulting characteristic P wave morphology. Knowledge of this anatomic distribution and P wave morphology allows targeted mapping and may facilitate successful RFA.

Adult↗
PubMed2000

Antibiotic resistance in bacteria of animal origin: methods in use to monitor resistance in EU countries.

A study on the ongoing monitoring programmes in 13 European countries was made as part of a concerted action funded by the European Commission. Five main reference systems were used in the surveyed countries and three categories of bacteria were monitored, zoonotic agents, indicator bacteria and veterinary pathogens. The five reference systems and an overview of the national monitoring programmes are described. Differences exist and there is a real need for standardisation at the European level. This harmonisation could be set up both for microbiological methods and the epidemiological results derived from common methods. Disk diffusion methods are most widely used and many of the monitored species and control strains are similar in the action's participating countries.

Animal Population Groups↗
PubMed2000

Cardiovascular adverse effects of antipsychotic drugs.

Minor cardiovascular adverse effects from antipsychotic drugs are extremely common. They include effects such as postural hypotension and tachycardia due to anticholinergic or alpha1-adrenoceptor blockade, and may occur in the majority of patients at therapeutic dosages. There are a number of pharmacological effects that are of uncertain clinical significance, such as blockade of calmodulin, sodium and calcium channels and alpha2-adrenoceptors in the central nervous system. The most serious consequences of treatment, arrhythmias and sudden death, are probably uncommon and are most likely to be caused primarily by blockade of cardiac potassium channels such as HERG. Incomplete evidence suggests that arrhythmias and sudden death are a particular problem with certain drugs (thioridazine and droperidol), high risk populations (elderly, pre-existing cardiovascular disease, inherited disorders of cardiac ion channels or of antipsychotic drug metabolism) or people taking interacting drugs (such as drugs that prolong the QT interval, e.g. tricyclic antidepressants, drugs that inhibit antipsychotic drug metabolism, or diuretics). Clozapine may be unique in also causing death from myocarditis and cardiomyopathy. Much further research is required to more clearly identify high risk drugs and the populations that are at risk of sudden death, as well as the mechanisms involved and the extent of the risk.

Adult↗
PubMed1999

Simultaneous determination of enrofloxacin and ciprofloxacin in animal biological fluids by high-performance liquid chromatography. Application in pharmacokinetic studies in pig and rabbit.

A simple and rapid high-performance liquid chromatographic method for the simultaneous determination of enrofloxacin and ciprofloxacin has been developed in pig and rabbit samples. Solid-phase extraction was applied from samples on a C18 cartridge using a mixture of methanol-hydrochloric acid (98:2, v/v). Analytical separation was performed on a C18 column with UV detection at 277 nm under gradient conditions. The mobile phase was a mixture of orthophosphoric acidtriethylamine-acetonitrile. The method has been validated for both molecules in pig and rabbit plasma and adapted for rabbit tissue-cage fluid (TCF). The assay is specific and reproducible within the both drugs and mean recoveries for ciprofloxacin and enrofloxacin, respectively, were 92+/-6% and 90+/-5% for pig plasma over the range used. Mean recoveries for enrofloxacin were 108+/-9% and 102+/-7% for rabbit plasma and TCF, respectively, over the range used. The suitability of the assay for pharmacokinetic studies was determined by measuring enrofloxacin and ciprofloxacin concentrations either in pig plasma after administration of a single intravenous 5 mg/kg dose of enrofloxacin or in rabbit plasma and TCF during a 24 h infusion of enrofloxacin at a rate of 1.25 mg/kg per hour.

Animals↗
PubMed1998

Determination of flumequine and 7-hydroxyflumequine in plasma of sheep by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of flumequine and its metabolite 7-hydroxyflumequine in sheep plasma was described. The two compounds were extracted from 100 microl of plasma by liquid-liquid extraction. Aliquots (100 microl) were injected onto the HPLC system and separated on a LiChrospher Select B column with an isocratic system. The compounds were detected by fluorimetric detection for concentrations below 500 microg/l and by UV detection for the concentrations exceeding 500 microg/l. The range of the validated concentrations were 50000 to 5 microg/l and 500 to 10 microg/l with mean recovery rates of 87+/-3% and 60+/-1% for flumequine and 7-hydroxyflumequine, respectively.

Animals↗
PubMed1998

Moderators of gender effects on parents' talk to their children: a meta-analysis.

Two sets of meta-analyses of studies examining gender effects on parents' observed language with their children were conducted. One looked at studies comparing mothers and fathers in amount of talking, supportive speech, negative speech, directive speech, informing speech, and questions and requests. The other looked at studies comparing mothers' interactions with daughters versus with sons in amount of talking, supportive speech, and directive speech. Across studies, mothers tended to talk more (d = .26), use more supportive (d = .23) and negative (d = .13) speech, and use less directive (d = .19) and informing (d = .15) speech than did fathers. Also, mothers tended to talk more (d = .29) and use more supportive speech (d = .22) with daughters than with sons. Medium or large effect sizes occurred in most analyses when particular moderator variables were taken into account. Effect sizes varied, depending on aspects of the interactive setting, the child's age, sampling and measurement, and publication characteristics. The results are interpreted in relation to a contextual-interactive model of gender typing.

Child↗
PubMed1998

A genome-wide functional assay of signal transduction in living mammalian cells.

We describe a genome-wide functional assay for rapid isolation of cell clones and genetic elements responsive to specific stimuli. A promoterless beta-lactamase reporter gene was transfected into a human T-cell line to generate a living library of reporter-tagged clones. When loaded with a cell-permeable fluorogenic substrate, the cell library simultaneously reports the expression of a large number of endogenous genes. Flow cytometry was used to recover individual clones whose reporter-tagged genes were either induced or repressed following T-cell activation. Responsive clones were expanded and analyzed pharmacologically to identify patterns of regulation associated with specific genes. Although demonstrated using T cells, the genomic assay could be applied to map downstream transcriptional consequences for any propagating cell line in response to any stimulus of interest.

Cell Separation↗
PubMed1998

Simultaneous determination of six quinolones in pig muscle by liquid chromatography-atmospheric pressure chemical ionisation mass spectrometry.

An LC-MS method is described for the confirmation of six quinolones (enrofloxacine, ciprofloxacine, marbofloxacine, danofloxacine, sarafloxacine and difloxacine) in pig muscle. The quinolones were extracted from muscle (2 g) with phosphate buffer (pH 7.4). After centrifugation, the extract was purified on a C18 solid-phase extraction cartridge. Samples were analysed by LC with gradient elution on a C18 column and detected by MS via an atmospheric pressure chemical ionisation interface. For each compound, an intense pseudo-molecular ion [M+H]+ is obtained. The assay is specific and reproducible and allows the confirmation of the six quinolones at the 7.5 micrograms kg-1 level in pig muscle.

Animals↗
PubMed1998

Results of a European interlaboratory study for the determination of oxytetracycline in pig muscle by HPLC.

An interlaboratory study was organised in 1996 in order to determine laboratory testing performance for measuring oxytetracycline (OTC) and 4-epioxytetracycline (4-epiOTC) residues in pig muscle. The organisation was designed according to the 'International Harmonised Protocol for Proficiency Testing of (Chemical) Analytical Laboratories' produced by the Association of Official Analytical Chemists (AOAC International) and the International Union of Pure and Applied Chemistry (IUPAC). Fourteen National Reference Laboratories (NRLs) out of the 15 asked to participate agreed to analyse the samples. These laboratories were from 13 different European Union (EU) Member States and each participant was allowed to use the extraction method of their own choice but had to use liquid chromatography as the analytical technique. Most of the methods used were based on UV detection (simple wavelength or diode-array detection) but some involved fluorimetric detection. The production of incurred samples was prepared on-site. The OTC and 4-epiOTC concentrations present in the samples were determined by taking the mean of the results (excluding outliers) and the deviation of each result from the assigned value was measured. The performance of the laboratories was evaluated by calculating the 'z-scores'. The results were globally satisfactory and showed that all 14 laboratories were capable of determining OTC and 4-epiOTC in pig muscle with satisfactory accuracy. Only two laboratories obtained a questionable result in terms of repeatability.

Animals↗
PubMed1998

Soluble platelet endothelial cell adhesion molecule-1 (sPECAM-1) in inflammatory vascular disease, atherosclerotic vascular disease, and in cancer.

Cell surface adhesion molecule expression is likely to be important in inflammation, atherosclerosis and cancer, and soluble forms of many of these molecules are present in plasma. We measured levels of the soluble form of platelet endothelial cell adhesion molecule-1 (sPECAM) by ELISA in the serum of 77 patients with frank atherosclerosis, 69 patients with inflammatory connective tissue disease, and 39 patients with cancer. Each group of patients was controlled by an equal number of age- and sex-matched healthy subjects. There was no difference between sPECAM in patients with atherosclerosis and their matched controls or between patients with connective tissue disease and their controls. However, sPECAM levels were lower (16.6 +/- 5.0 ng/ml, mean +/- SD) in patients with cancer than in their controls (21.1 +/- 4.4 ng/ml, P < 0.001). No differences were found in sPECAM levels between the major subgroups of each type of disease, or as a result of factors such as age, sex or smoking in the controls. In contrast to levels of many other soluble adhesion molecules, levels of sPECAM are not altered in inflammatory or atherosclerotic vascular disease and therefore appear to have little relevance in these conditions. However, there may be significant differences in sPECAM levels in patients with low levels in cancer. Additional investigations are therefore justified.

Adult↗
PubMed1998

Methods of responding to healthcare security incidents.

This paper considers the increasing requirement for security in healthcare IT systems and, in particular, identifies the need for appropriate means by which healthcare establishments (HCEs) may respond to incidents. The main discussion focuses upon two significant initiatives that have been established in order to improve understanding and awareness of healthcare security issues. The first is the establishment of a dedicated Incident Reporting Scheme (IRS) for HCEs, enabling the level and types of security incidents faced within the healthcare community to be monitored and advice appropriately targeted. The second aspect presents a description of healthcare security World Wide Web service, which provides a comprehensive source of advice and guidance for establishments when trying to address and prevent IT security breaches. The discussion is based upon work that is currently being undertaken with the ISHTAR (Implementing Secure Healthcare Telematics Applications in Europe) project, as part of the Telematics Applications for Health programme of the European Commission.

Computer Security↗