ABSTRACT
The response of human skin to topical methyl nicotinate (MN) has been monitored in black, oriental, and caucasian subjects. The study aimed to address the question: "Do racial differences in percutaneous absorption and microcirculatory sensitivity exist?" MN-induced vasodilatation was assessed visually and by laser Doppler velocimetry (LDV). At three dose levels, in the three subject populations, four parameters were compared: (a) the diameter of the maximum visually perceptible erythematous area (Emx); (b) the area under the erythematous diameter versus time curve (AUE); (c) the maximum LDV response (Lmax); and (d) the area under the LDV response versus time curve (AUL). At p less than 0.05, AUL (black) greater than AUL (caucasian) for all MN concentrations; AUL (oriental) greater than AUL (caucasian) for the higher dose levels. Emx, AUE and Lmx showed no significant differences between races within concentrations. For all subjects, Emx, AUE, and AUL were significantly dependent on MN dose whereas Lmx was not. The results suggest that some racial differences in response to topical MN exist and that perception of these distinctions may depend upon the method of measurement.
Subject(s)
Asian People , Black People , Epidermis/physiology , Nicotinic Acids/adverse effects , White People , Administration, Cutaneous , Adult , Epidermis/blood supply , Epidermis/drug effects , Humans , Microcirculation/physiology , Nicotinic Acids/administration & dosageABSTRACT
Verapamil, a calcium antagonist, is effective in delaying death in mice after i.v. challenge with sea nettle (Chrysaora quinquecirrha) or Portuguese man-o'war (Physalia physalis) crude venom. Death caused by these venoms could also be delayed by prior medication of the animals. Continuous EKG monitoring of sea nettle venom-challenged rats demonstrated that a single rapid injection of verapamil might require 4 min to be effective and that up to four repeated injections may be necessary to counteract the venom-induced abnormalities. Verapamil reduced the sea nettle venom-induced positive inotropic effect on isolated guinea pig atrial strips. These data further indicate the effectiveness of verapamil as a therapeutic agent against jellyfish cardiotoxins.