PubMed Health⌕ Search

Biomedical subjects

R Hartwick

Publications and source records attributed to R Hartwick.

3 recordsLinked to original sources

Disarming the box-jellyfish: nematocyst inhibition in Chironex fleckeri.

Laboratory tests indicate that methylated spirits, widely espoused as a first-aid treatment for jellyfish stings, causes massive discharge of nematocysts in living tentacles of the box-jellyfish, Chironex fleckeri. This action, together with demonstrated hazards of flammability and intoxication, casts doubt on this substance as a treatment for Chironex stings. In an attempt to find a substitute which will be effective in inactivating unfired nematocysts in the tentacles adhering to sting victims, a number of substances were tested in the laboratory. Weak solutions of acetic acid, as well as commerical vinegar, were found to inactivate the penetrating nematocysts of Chironex rapidly and completely. Most other substances tested proved less effective, and some actually stimulated the firing of nematocysts.

Acetates↗

An optimized assay for adenosine deaminase using reverse phase high pressure liquid chromatography.

A sensitive, optimized assay for adenosine deaminase (E.C. 3.5.4.4), is presented which is based on a reverse phase HPLC analysis of adenosine. In this method a sample of erythrocytes was incubated with adenosine and the decrease in the adenosine concentration with time was analyzed by HPLC. The precision of the method averaged approximately 5% RSD with a sensitivity of about 0.1 U/ml of packed erythrocytes. Comparison with other literature values showed similar activities for adenosine deaminase in erythrocytes (0.229 +/- 0.025) U/ml (alpha = 0.05). The optimization included studies on the ionic strength, pH, enzyme and substrate concentration, and reaction time. The Km for adenosine deaminase was found to be (0.178 +/- 0.018) mM (alpha = 0.05). The method offers several advantages over other assay methods, including an improved capability to discern competing side reactions from other enzymes.

Adenosine Deaminase↗