How reliable are test results from 17 laboratories on the basis of EN 1500 for a hand rub based on 80% (w/w)?

INTRODUCTION: A ring trial organized by the Association of Applied Hygiene (VAH) on the bactericidal efficacy of an ethanol-based hand rub was carried out in 17 laboratories according to EN 1500 with the aim of describing the variability of test results and fulfilment of the methodological acceptance criteria. METHOD: As a test product, a hand rub based on 80% ethanol (w/w) was tested in comparison with the reference alcohol (60% iso-propanol, v/v) in a crossover design. After pre-washing and contamination following the norm, hands were treated either with the reference alcohol (2 × 3 mL for 2 × 30 s) or the test product (3 mL in 30 s). Post-decontamination values were determined immediately after the rub-in period. Validated neutralizers were used. The arithmetic means of all individual log10 pre-values, post-values and reduction values were calculated per laboratory. Non-inferiority was assumed when the Hodges-Lehmann 97.5% confidence limit was <0.6 in comparison with the reference. A z-score was calculated to determine the laboratory performance. RESULTS: Two laboratories did not meet the acceptance criteria and were excluded from the analysis. The bactericidal efficacy of the test product was non-inferior to the reference product in four laboratories and not non-inferior in 11 laboratories. The z-score for the Hodges-Lehmann 97.5% confidence limit indicated a satisfactory performance in all laboratories. CONCLUSION: We consider the EN 1500 test method to be robust in terms of the variability of test results. For products of borderline efficacy, the evaluation should be based on more than one test.

Synthesis of isoquinolines and pyridines by the palladium-catalyzed iminoannulation of internal alkynes.

A wide variety of substituted isoquinoline, tetrahydroisoquinoline, 5,6-dihydrobenz[f]isoquinoline, pyrindine, and pyridine heterocycles have been prepared in good to excellent yields via annulation of internal acetylenes with the tert-butylimines of o-iodobenzaldehydes and 3-halo-2-alkenals in the presence of a palladium catalyst. The best results are obtained by employing 5 mol % of Pd(OAc)(2), an excess of the alkyne, 1 equiv of Na(2)CO(3) as a base, and 10 mol % of PPh(3) in DMF as the solvent. This annulation methodology is particularly effective for aryl- or alkenyl-substituted alkynes. When electron-rich imines are employed, this chemistry can be extended to alkyl-substituted alkynes. Trimethylsilyl-substituted alkynes also undergo this annulation process to afford monosubstituted heterocyclic products absent the silyl group.

Synthesis of isoindolo[2,1-alpha]indoles by the palladium-catalyzed annulation of internal acetylenes.

A wide variety of substituted isoindolo[2,1-alpha]indoles have been prepared via annulation of internal alkynes by imines derived from o-iodoanilines in the presence of a palladium catalyst. This methodology provides an extremely efficient route for the synthesis of these tetracyclic heterocycles from readily available starting materials. The mechanism of this interesting annulation process appears to involve (1) oxidative addition of the aryl iodide to Pd(0), (2) alkyne insertion, (3) addition of the resulting vinylic palladium intermediate to the C-N double bond of the imine, (4) either electrophilic palladation of the resulting sigma-palladium intermediate onto the adjacent aromatic ring derived from the internal alkyne or oxidative addition of the neighboring aryl carbon-hydrogen bond, and (5) reduction of the tetracyclic product and Pd(0). A variety of internal acetylenes have been employed in this annulation process in which the aromatic ring of the alkyne contains either a phenyl or a heterocyclic ring.

Genotypic analysis of pseudoepidemic due to contamination of Hanks' balanced salt solution with Candida parapsilosis.

A cluster of isolates of Candida parapsilosis recovered from clinical specimens was demonstrated, by both classical and molecular epidemiological techniques, to have resulted from contamination in the laboratory. The source of the pseudoepidemic was a repeatedly utilized contaminated container of Hanks' balanced salt solution used in specimen processing. The patterns of restriction fragment length polymorphisms of DNA extracted from the clinical and environmental isolates were identical to each other but composed a newly identified unique C. parapsilosis DNA type.