Modified Dakin's solution for cutaneous vibrio infections.

Vibrio species, specifically Vibrio vulnificus, are known to be endemic to warm saltwater environments. As a human pathogen they are capable of causing severe, progressive, necrotizing infections. The lesions are bullous in nature and often require wide surgical debridement due to the aggressiveness of this organism. The literature supports prophylactic antibiotic therapy for those with preexisting hepatic dysfunction or immunocompromise. The authors routinely implement prophylactic antibiotic coverage with doxycycline 100 mg every 12 hours for vibrio in patients with wounds exposed to or acquired in saltwater. In addition, they institute topical therapy with 0.025% sodium hypochlorite solution (modified Dakin's), based on their in vitro study of vibrio sensitivity to antimicrobials. Over the past 2 years, the authors have treated 10 patients with this protocol for cutaneous vibrio infections confirmed by quantitative cultures. None of these patients experienced progression of infection requiring operative debridement-contrary to the aggressive nature of this organism documented in other reports.

Electron microscopic localization of the beta-adrenergic receptor using a ferritin-alprenolol probe.

This report describes electron microscopic localization of the beta-adrenergic receptor using a beta-adrenergic receptor antagonist conjugated to ferritin. The conjugate was synthesized by reacting a carboxylic acid derivative of alprenolol with ferritin. The ferritin-alprenolol compound was shown to be effective in displacing specific [3H]dihydroalprenolol binding from rat erythrocyte membranes with a dissociation constant (Kd) of 25 nM. Rat erythrocyte ghosts were incubated with the compound and quantitative electron micrographic analysis yielded total binding of 1367 +/- 129 ferritin particles and nonspecific binding of 688 +/- 111 (six experiments). Thus, specific binding was 680 +/- 60 ferritin particles per red cell profile. Qualitative observations suggested that the particles were distributed randomly on the surface of the erythrocyte, although an occasional cluster was seen. A compound from another synthesis was shown be to effective in displacing specific [125I]iodocyanopindolol binding from neonatal rat cardiac myocyte membranes, with a dissociation constant of 13.8 nM, whereas native alprenolol had a dissociation constant of 1.3 nM. Neonatal rat cardiac myocytes were incubated with the compound and processed for electron microscopy. Total binding along the sarcolemmal membrane was 504 +/- 38 ferritin particles/100 micron of membrane and nonspecific binding was 301 +/- 26 ferritin particles/100 micron of membrane (seven experiments), yielding specific binding of 203 ferritin particles/100 micron of membrane. In additional studies, specific binding was inhibited 95% with 10(-5) M l-isoproterenol and 29% with d-isoproterenol, indicating stereoselectivity (seven experiments). The probe was distributed randomly along the sarcolemma with no preferential localization to coated pits or other membrane specializations. From measurements of the surface area of the average cardiac myocyte (732 micron 2), the specific binding of ferritin-alprenolol per 100 micron of membrane (203), and section thickness (0.08 micron), we calculated that cardiac myocytes had 18,575 beta-adrenergic membrane receptor sites. Thus, we have described a method for synthesizing and applying an electron-dense probe for electron microscopic localization of beta-adrenergic receptors. In these studies we determined the distribution of these receptors on rat erythrocyte ghosts and neonatal rat cardiac myocytes.

Differences in affinity of cardiac beta-adrenergic receptors for [3H]dihydroalprenolol.

We performed quantitative light microscopic autoradiography of [3H]dihydroalprenolol (DHA) binding to frozen sections of canine myocardium to test the hypothesis that there are differences in the density or affinity of beta-adrenergic receptors on various tissue compartments. In one study, with concentrations of [3H]DHA from 0.34 to 5.1 nM, specific binding to cardiac myocytes was saturable, whereas nonspecific binding was linear with ligand concentration. Arterioles had more specific grain counts than muscle cells (P less than 0.0001), and Scatchard analysis showed that the arterioles had a much higher affinity for [3H]DHA than myocytes. In a second study with lower concentrations of [3H]DHA (0.19-1.98 nM), binding to the arterioles saturated, whereas binding to the cardiac myocytes did not. Specific binding to arterioles was significantly higher (P less than 0.0001) than binding to myocytes at all concentrations of [3H]DHA. The dissociation constants for the subendocardial and subepicardial myocytes were 1.57 and 1.71 nM, respectively, while the dissociation constant for the arterioles was 0.26 nM. The maximum number of binding sites was 911 grains/0.9 X 10(-2) mm2 for subepicardial myocytes, 936 for subendocardial myocytes, and 986 for arterioles. The large nerves accompanying an epicardial artery also demonstrated specific [3H]DHA binding. Thus this study has demonstrated major differences in the distribution and affinity of beta-adrenergic receptors, which may help to explain various physiological responses to beta-adrenergic stimulation.

Alpha-2 adrenergic receptor localization in the rat heart and kidney using autoradiography and tritiated rauwolscine.

To study the distribution and characterization of alpha-2 adrenergic receptors in the rat heart and kidney, we used light microscopic autoradiography and a computer-based image analyzer to quantify the localization of [3H]rauwolscine (RAUW) binding. Scintillation spectrometry of frozen sections of rat kidney demonstrated rapid binding, saturability, stereospecificity and agonist and antagonist binding characteristic of an alpha-2 adrenergic receptor. For autoradiography, sections of rat kidney and heart were incubated in several concentrations of [3H]RAUW in the absence of (total binding) and in the presence of (nonspecific binding) 10(-5) M yohimbine. The sections were processed and grain density quantified using a computer-based image analyzer. The tubules in the renal cortex had significantly more specific [3H]RAUW labeling than either the renal glomeruli or the tubules in the renal medulla at all concentrations of [3H]RAUW used (P less than .0001). Nonspecific binding was significantly higher over the cortical tubules than either the glomeruli or the tubules in the renal medulla (P less than .0001). Scatchard analysis of specific grain densities determined that the tubules in the renal cortex had the highest density of any structure studied [maximum binding (Bmax) = 1182 grains/10(-2) mm2]. The glomeruli had a Bmax of 485 grains/10(-2) mm2, whereas the tubules in the renal medulla had a Bmax of 273 grains/10(-2) mm2. There were no significant differences among these three regions in the dissociation constant of the [3H]RAUW. When analyzing the heart, we found no specific [3H]RAUW labeling over either the cardiac myocytes or the myocardial arterioles.(ABSTRACT TRUNCATED AT 250 WORDS)