Measurements of magneto-Rayleigh-Taylor instability growth during the implosion of initially solid Al tubes driven by the 20-MA, 100-ns Z facility

The first controlled experiments measuring the growth of the magneto-Rayleigh-Taylor instability in fast (∼100  ns) Z-pinch plasmas are reported. Sinusoidal perturbations on the surface of an initially solid Al tube (liner) with wavelengths of 25-400  μm were used to seed the instability. Radiographs with 15  μm resolution captured the evolution of the outer liner surface. Comparisons with numerical radiation magnetohydrodynamic simulations show remarkably good agreement down to 50  μm wavelengths.

Adherence to clinical guidance in the prescribing of oral antithrombotic medication in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation is the commonest cardiac rhythm disturbance and is an independent risk factor for stroke; however, use of oral antithrombotic therapy is reported to be suboptimal in clinical practice.

AIM

The aim of the study was to evaluate the prescribing rates of oral antithrombotic therapy in patients with atrial fibrillation to determine if prescribing patterns reflected published clinical guidance.

METHOD

Patients with atrial fibrillation, admitted to hospital over a 12-week period were identified and their antithrombotic therapy regimen was analysed using statistical methods.

RESULTS

Although 87/100 patients identified were prescribed OAT, the regimen was suboptimal in 35 patients. Patients aged 75 years and older were more likelyto be receiving suboptimal oral antithrombotic treatment compared with younger patients

CONCLUSIONS

The benefits and suitability of oral antithrombotic therapy for patients of all ages need to be more comprehensively communicated to prescribers.

Decoloration of textile dyes by alginate-immobilized Trametes versicolor

Alginate-immobilized Trametes versicolor decolorized Amaranth at similar rates in repeated batch culture when the dye was present in either (i) modified Kirk's medium containing 0.22 gl(-1) ammonium tartrate, (ii) the same buffer, thiamine, trace elements and glucose concentrations as in the modified Kirk's medium, or (iii) glucose alone at either 1, 5 or 10 gl(-1). With glucose alone (0.5 gl(-1)), Amaranth, Reactive Black 5, Reactive Blue 19 and Direct Black 22 had first-order decoloration rate constants of 0.56, 0.76, 0.52, and 0.15 h(-1), respectively. Mixtures of these dyes were also completely decolorized. After four successive decolorations, beads were kept in storage solutions for 48 d at 6 degrees C. CaCl2 (1g l(-1)) was the best storage solution as the beads were easier to handle and had the fastest decoloration rates after storage. Decoloration rates were faster with lower viscosity (less than 2000 cps) alginates and with softer beads which had a lower resistance to compression. Fungal colonization of the beads resulted in higher biomass concentrations with a corresponding higher decoloration rate but the beads became larger, had a lower resistance to compression and a higher percentage of bead breakage in a stirred tank reactor. Biomass, recovered from beads in which there was no growth, could be dispersed while the biomass from colonized beads formed a hollow, spherical shell due to growth on and near the bead surface and no growth in the bead interior. If alginate-immobilized T. versicolor is to be used in a stirred tank reactor, a high biomass loading during the immobilization phase and no fungal growth in the beads is recommended to have high decoloration rates and low bead breakage.

Total homocysteine is not a determinant of arterial pulse wave velocity in young healthy adults

AIMS

Hyperhomocysteinaemia has been associated with reduced pulse wave velocity (PWV) in patients with end-stage renal disease and in those with hypertension. The aim of this study was to examine the association between total homocysteine (tHcy) concentrations, the biochemical and genetic determinants of tHcy and PWV in healthy young adults.

METHODS AND RESULTS

A total of 489 subjects aged 20-25 years participated. A fasting blood sample was taken and PWV measured using a non-invasive optical method. tHcy did not correlate with PWV, whether assessed at the aorto-iliac segment (P = 0.18), the aorto-radial segment (P = 0.39) or the aorto-dorsalis-pedis segment (P = 0.22). When tHcy was classified into normal (<15) and high (> or =15micromol/l), PWV did not differ between the two groups at any segment. PWV did not differ by MTHFR C677T or NOS3 G894T genotype, even when smoking and folate sub-groups were considered. Considering aortic PWV as a dependent variable, stepwise regression analysis showed that the only parameter entering the model for all segments was systolic blood pressure (aorto-iliac, P < 0.001; aorto-radial, P = 0.01; aorto-dorsalis-pedis, P = 0.001). Age, sex, COL1A1 genotype and triglycerides entered the model significantly for two of three segments.

CONCLUSION

This study shows that arterial PWV is not associated with tHcy in a healthy young population.

A sensitive HPLC-MS-MS assay for quantitative determination of midazolam in dog plasma

The clinical pharmacokinetics of midazolam have been extensively studied, due to its high clearance by CYP3A4 and sensitivity to drug-drug interactions. In order to investigate the potential to model drug-drug interactions with midazolam in the dog, a selective and sensitive high performance liquid chromatography-tandem mass spectroscopy (HPLC-MS-MS) method has been developed, with sufficient sensitivity to allow analysis of dog plasma samples generated following administration of a clinically relevant dose. The method involves extraction of midazolam and internal standard (flunitrazepam) from dog plasma, using 96-well Oasis MCX solid phase extraction plates. The assay has been validated over a concentration range of 0.1-10 ng/ml and its specificity, accuracy and precision demonstrated. The relative bias of the assay was within +/-15% for all standards with intra- and inter-assay precision (coefficient of variation-%CV) of less than 15%. The assay was applied to the analysis of plasma samples (0.2 ml), generated following intravenous or oral administration of midazolam to male beagle dogs, at a dose level of 0.05 mg/kg, and pharmacokinetic parameters were derived from the resulting data.

Associations between physical fitness and activity patterns during adolescence and cardiovascular risk factors in young adulthood: the Northern Ireland Young Hearts Project

The aim of the present study was to examine relationships between cardiovascular disease (CVD) risk factor status in young adulthood (mean age = 22.5 yrs) and antecedent physical fitness and physical activity at ages 12 and 15 years. The data were obtained from the Young Hearts Project, a longitudinal observational study of CVD risk factors in a representative sample of young people from Northern Ireland. Physical fitness was measured by the 20-metre endurance shuttle run, and physical activity and sports participation by a self-report recall questionnaire. CVD risk factors examined included serum total cholesterol (TC) and HDL cholesterol concentrations, the TC:HDL ratio, systolic and diastolic blood pressure and body fatness (sum of four skinfolds). Linear regression analyses showed modest relationships between physical fitness in adolescence and both TC:HDL ratio and body fatness in young adulthood. No such relationships were apparent for adolescent physical activity. The promotion of physical fitness during adolescence may reduce exposure to other risk factors lasting into early adulthood.

Preparation and opioid activity of analogs of the analgesic dipeptide 2,6-dimethyl-L-tyrosyl-N-(3-phenylpropyl)-D-alaninamide

A number of analogues of the recently disclosed analgesic dipeptide 2,6-dimethyl-L-tyrosyl-D-alanine-phenylpropylamide (SC-39566, 2) were prepared. These analogues contained oxymethylene, aminomethylene, ketomethylene, bismethylene, and trans double bond (including vinyl fluoride) isosteric replacements for the amide bond between the D-alanine and phenylpropylamine units in 2. These compounds were tested in opioid binding assays and in the mouse writhing assay for analgesic activity. Though not as potent as 2, the oxymethylene, and trans double bond isosteres showed analgesic activity. The aminomethylene analogues also showed binding activity in subnanomolar concentrations at the mu receptor. The amide bond between 2,6-dimethyl-L-tyrosine and D-alanine units seems to be critical for opioid activity.

Lymphocyte proliferation is associated with gender, caregiving, and psychosocial variables in older adults

We examined lymphocyte responses to mitogens [phytohemagglutinin (PHA), concanavalin A, pokeweed] in spouse caregivers of persons with Alzheimer's disease (n = 82; mean age = 69.4) and noncaregiver spouses (n = 83) group matched on age and gender. Data were collected at study entry (T1) and 15-18 months later (T2). In men (n = 52), a depressed mood factor was negatively related to all mitogen responses at T1 and PHA at T2. Loneliness was the most important variable in the depressed mood factor. No relationships occurred in women (n = 113). At T2 an anger expression factor (anger-out--anger-control) was negatively related to all mitogen responses in caregivers. Anger-out was the most important variable for anger expression. Depressed mood at T1 predicted residualized changes in PHA at T2 in men. In conclusion, men with higher depressed mood and caregivers with higher anger expression may be at risk for lower proliferation responses.

Changes in seismic anisotropy after volcanic eruptions: evidence from Mount Ruapehu

The eruptions of andesite volcanoes are explosively catastrophic and notoriously difficult to predict. Yet changes in shear waveforms observed after an eruption of Mount Ruapehu, New Zealand, suggest that forces generated by such volcanoes are powerful and dynamic enough to locally overprint the regional stress regime, which suggests a new method of monitoring volcanoes for future eruptions. These results show a change in shear-wave polarization with time and are interpreted as being due to a localized stress regime caused by the volcano, with a release in pressure after the eruption.

Insulin-like growth factor -I deficiency

The insulin-like growth factor (IGF) system composed of two ligands, their receptors and regulatory proteins (acid-labile subunit and IGF-binding proteins) plays a central role in the regulation of growth and development in mammals. In addition to its key role in the stimulation of cellular proliferation and growth, IGF-I has important effects on carbohydrate, protein and bone metabolism. The molecular biology and physiology of the IGF system are complex, resulting in many potential mechanisms of IGF deficiency. Briefly, IGF-I deficiency may result from a primary defect in the IGF-I gene, its promoters, or may be secondary to a defect outside the gene itself. It may also result as a consequence of growth hormone (GH) deficiency, GH receptor/post-receptor abnormalities or abnormalities of the IGF-I receptor. The purpose of this presentation is to review the different types of IGF-I deficiency using the well-characterized clinical conditions with its associated biochemical and molecular defects. The clinical consequences in terms of phenotype-genotype, linear growth and body composition in patients with primary and secondary IGF deficiency will be presented, together with results from recombinant human (rh)IGF-I replacement therapy. Finally, as primary IGF-I deficiency is associated with insulin resistance, some of the metabolic actions of IGF-I will be briefly discussed.