Assessing metal transfer to vegetation and grazers on reclaimed pyritic Zn and Pb tailings.

A study of the concentrations of zinc and lead in an engineered soil capping system overlying sulphide mine tailings was undertaken. Tailings geochemistry, soil cover and vegetation were monitored over a 4-year period, and a cattle grazing demonstration exercise was conducted over a 1-year period. Whilst the tailings had a relatively high pyrite content and demonstrated oxidation, a circum neutral pH was observed for the duration of the study period due to the high dolomitic content. No evidence of metal mobility into the soil cover and vegetation was observed over the monitoring period. Relatively high Zn herbage content is attributed to the glacial till component of the soil cover. Similarly, no evidence of metal transfer to grazing cattle was observed through blood and tissue analysis with Zn content not significantly different from control animals. Pb tissue content was below limit of detection.

Effect of routine use of a multiplex PCR for detection of vanA- and vanB- mediated enterococcal resistance on accuracy, costs and earlier reporting.

A multiplex PCR (MPCR) for detection of vanA-and vanB-mediated resistance to vancomycin was optimized and adapted for use in the routine microbiology laboratory. Consecutive specimens (1196) submitted for vancomycin resistant Enterococci (VRE) surveillance were processed by clinical technologists on Bile Esculin Azide Agar containing 6 mg/L vancomycin (BEAA/Vanco6) plates and 466 showing black colony growth were processed by conventional biochemical testing (CBT) and by MPCR. CBT identified 208 VRE positives. MPCR detected 205 of the CBT- positives plus an additional 10. Analysis of the discordant specimens determined that 5 CBT- negative/MPCR-positive specimens also contained Enterococci with vanC resistance, 3 CBT-positive/MPCR-negative specimens were true positives, and 5 CBT-negative/MPCR-positive specimens occurred due to technical error. The sensitivity and specificity of MPCR were 98.4% and 96.1%. MPCR identifications of VRE were achieved approximately 48 h earlier than CBT and at 60% of the costs.

Risk of bacteremia from temporary hemodialysis catheters by site of insertion and duration of use: a prospective study.

BACKGROUND: Uncuffed, nontunneled hemodialysis catheters remain the preferred means to gain immediate access to the circulation for hemodialysis. Bacteremia is the primary complication that limits their use. The risk of bacteremia by site of insertion and duration of use has not been well studied. METHODS: Two hundred eighteen consecutive patients who required a temporary hemodialysis catheter were prospectively followed. RESULTS: Catheters were placed at 318 new insertion sites and remained in use for a total of 6235 days. The incidence of bacteremia was 5.4% after three weeks of placement in internal jugular vein and 10.7% after one week in femoral vein [relative risk for bacteremia 3.1 (95% CI, 1.8 to 5.2)]. The incidence of bacteremia was 1.9% one day after the onset of an exit site infection but increased to 13.4% by the second day if the catheter was not removed. Guidewire exchange for malfunction and patient factors did not significantly affect the risk of bacteremia. CONCLUSIONS: Internal jugular catheters may be left in place for up to three weeks without a high risk of bacteremia, but femoral catheters in bed-bound patients should be removed after one week. Catheter exchanges over a guidewire for catheter malfunction do not increase bacteremia rates. Temporary catheters should be removed immediately if an exit site infection occurs.

Clinical experience with ofloxacin in urinary tract infection.

Preliminary data from the U.S. regarding the safety and efficacy of ofloxacin in the treatment of urinary tract infections are presented. Treatment of uncomplicated urinary tract infections with either 200 mg or 300 mg ofloxacin b.i.d. was as effective as treatment with a standard therapy, co-trimoxazole. In another series of patients with underlying abnormalities of the urinary tract, ofloxacin therapy resulted in fewer failures and relapses than co-trimoxazole treatment. Ofloxacin was well tolerated in these studies.

Mechanisms of synaptic transmission in the retina.

This paper reviews the mechanisms of transmitter release, the kinetics of synaptic transfer, the mechanisms for the production of conductance changes by transmitters, and the nature of the conductance changes at synapses in vertebrate retina. A method for the culturing of adult retinal cells is described, together with preliminary experiments on the identification of cells in culture.

In vitro stereoselective metabolism of the psychotomimetic amine, 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane. An apparent enantiomeric interaction.

The stereoselective metabolism [R/S (metabolized) less than 1] of the psychotomimetic amine (R,S)-1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane in 10 000g rabbit liver homogenate supernatant and 100 000g microsomal fractions has been demonstrated with the aid of the chiral reagent (S)-N-pentafluorobenzoylprolyl-1-imidazolide and GLC analyses. In contrast to the enantiomeric discrimination observed with racemic amine, the individual isomers were metabolized at approximately the same rate. This apparent enantiomeric interaction illustrates the fact that racemates should be viewed as unique chemical species with pharmacodynamic and toxicologic profiles potentially different from the individual antipodes.