An 'artificial mussel' for monitoring heavy metals in marine environments.

A new chemical sampling device, artificial mussel (AM), has been developed for monitoring metals in marine environments. This device consists of a polymer ligand suspended in artificial seawater within a Perspex tubing, and enclosed with semi-permeable gel at both ends. Laboratory and field experiments were carried out to examine the uptake of five metals (Cd, Cr, Cu, Pb and Zn) by the AM. Uptake of metals by AM was proportional to the exposure metal concentrations, and the AM was able to accumulate the ASV labile fractions of metals. Uptake and release of the metals of AM are similar to those of the mussel Perna viridis, but less affected by salinity and temperature. Field studies demonstrated that the AM can not only provide a time-integrated estimate of metals concentrations, but also allows comparisons of metal levels in different environments and geographical areas beyond the natural distribution limits of biomonitors.

Regulation of bradykinin receptor level by cholera toxin, pertussis toxin and forskolin in cultured human fibroblasts.

1. The effect of bacterial toxins on bradykinin-triggered release of arachidonic acid was studied in serum-deprived human foreskin (HSWP) fibroblasts prelabelled with [3H]-arachidonic acid. An 18-h exposure of HSWP cells to cholera toxin, pertussis toxin, or forskolin enhanced the bradykinin-stimulated release of arachidonic acid and metabolites. 2. Prolonged treatment of HSWP cells with these agents also caused a 3 to 4 fold rise in cell surface [3H]-bradykinin binding. The rise was inhibited by concurrent incubation with cycloheximide or actinomycin D. In addition, cholera toxin and foreskolin increased [3H]-bradykinin binding in wildtype PC12 cells, but not in mutant PC12 cells with reduced cyclic AMP-dependent protein kinase type II activity. 3. In conclusion, cholera toxin, pertussis toxin and forskolin enhanced arachidonic acid release in response to bradykinin, and increased the number of bradykinin receptors in HSWP fibroblasts. A cyclic AMP-dependent mechanism appears to mediate the actions of the toxins and forskolin.

Direct analysis of salicylic acid in keratolytic plaster by gas-solid chromatography.

A rapid gas-solid chromatographic method is reported for the direct analysis of salicylic acid in keratolytic plaster. The method requires no preseparation or derivatization and takes about 14 min. Since it requires only 2-7 mg of sample, it can determine the salicylic acid concentration in a particular area of plaster. The analyzing column is packed with porous polymer beads of 2,6-diphenyl-1,4-phenylene oxide. An automatic solid sampling system is used to connection with the gas chromatograph employing dual flame-ionization detectors. The average recovery of salicylic acid in synthetic samples containing 400-2700 microgram was 100.6 +/-1.6%. The average correlation coefficient of the peak area against the standard was +0.9995 +/- 0.0003 for samples in the 300-3000-microgram range.

The zero pressure fixed medtronic intact porcine valve: an 8.5 year review.

The Medtronic Intact valve is the only porcine valve which is fixed in glutaraldehyde at zero pressure. This preserves near normal extensibility of the leaflet collagen, enabling full leaflet opening without kinking, which in turn should improve durability compared with low and high pressure fixed valves. From 1983 to 1991, 265 patients had 276 Intact valves inserted (125 aortic, 129 mitral, 22 tricuspid). The mean age was 53 years (10-81), with 24% below 40 years. The 100% follow up represents 911 patient years and averaged 50 months (3-106) in survivors. The actuarial survival was 54% +/- 9% at eight years, compared with a matched general population of 82%. The mean NYHA class was 3.2 preoperatively and 1.2 at follow up. At eight years, freedom from infective endocarditis was 97% +/- 1%, from thromboembolism 89% +/- 3%, and from non-structural dysfunction 96% +/- 2%. Reoperation was required in three patients for infective endocarditis, in six for non-structural dysfunction and in seven for structural valve deterioration (SVD). Freedom from SVD in the aortic position (mean age 59 years) was 100%, in the tricuspid position (mean age 48 years) 80% +/- 7%. In the mitral position, freedom from SVD was 86% +/- 10% in patients aged 60 years or more (n = 39, two events), 96% +/- 4% in those aged 40-59 years (n = 23, one event in a patient with renal failure), 67% +/- 16% in those aged 20-39 years (n = 31, three events in two following pregnancy) and 38% +/- 28% in those under 20 years (n = 9, two events).(ABSTRACT TRUNCATED AT 250 WORDS)

The zero pressure fixed medtronic intact porcine valve: clinical results over a 6-year period, including serial echocardiographic assessment.

Between 1983 and 1990, 219 patients had 224 Medtronic Intact porcine valves inserted. There were 94 aortic, 110 mitral, and 20 tricuspid valve replacements. The mean patient age was 52 years. Mean follow-up was 33.3 months and was 97.7% complete. There was only one example of structural valve degeneration occurring at 25 months, giving an actuarial freedom of 99% at 6 years. Reoperation was performed in seven patients. At 6 years, actuarial survival was 71%, freedom from infective endocarditis 96%, freedom from thromboembolism 91%, freedom from reoperation 93%, and freedom from valve-related complications 86%. Doppler echocardiography was performed in 48 of the 70 patients operated upon between August 1983 and October 1986 and who remained alive at the current review. Their follow-up averaged 4.7 (3-6.7) years. The results were compared to a similar examination performed in 1987 by the same operator. No patient had significant regurgitation. Valve gradients and areas remained the same in the two studies in the mitral position (3.8 +/- 1.33 mmHg) and the mean aortic gradient had reduced from 17 +/- 5.2 mmHg in 1987 to 13 +/- 2.8 mmHg in the current study (p = 0.02). These medium-term results are considered encouraging.