Argon laser stapedectomy using an endo-otoprobe system

In summary, we believe that the endo-otoprobe system offers several advantages to the otologist. The system is safe and relatively inexpensive. The probes are designed to provide tactile feedback similar to that of standard otologic instruments and avoid the use of a cumbersome micromanipulator. There are currently shapes that are similar to a Rosen needle, Shea pick, and bayonet. We hope most otologists will find that one of the endo-otoprobes fits their particular style of surgery.     

105Changes in Nitric Oxide Levels After Deep Dermal injury in the Female,Red Duroc Pig (FRDP)

Introduction : Hypertrophic scar is a devastating sequel to burns and other tangential skin injuries. It follows deep dermal injuries and does not occur after superficial injuries. Nitric oxide (NO) plays many important roles in wound healing from inflammation to scar remodeling. Studies have shown that expression of nitric oxide synthase and nitric oxide production are decreased in human hypertrophic scar. However little is known about NO involvement in the early stages of hypertrophic scarring, because of the lack of an animal model. It was recently reported that the female red Duroc pig (FRDP) makes thick scar, which is similar to human hypertrophic scar. We hypothesized that NO production in wounds on the female, red Duroc pig is similar to that of human hypertrophic scar and that NO involvement in deep wounds is different from that in superficial wounds. Methods : Superficial (0.015” to 0.030”) and deep (0.045” to 0.060”) wounds were created on the backs of four FRDPs. Biopsies were collected at weeks 1.5, 4, 8 and 21 post wounding including samples of uninjured skin. Nitric oxide levels were measured with the Griess reaction assay and normalized with tissue protein level. Results : Superficial wounds healed with an invisible scar whereas the deep wounds healed with scar resembling mild hypertrophic scar. The thickness of the scars from the deep wounds was significantly greater than uninjured skin and healed superficial wounds (p < 0.01). NO levels were increased at 1.5 weeks in deep wounds compared to superficial wounds and uninjured skin (p < 0.05). At 8 weeks, NO levels in deep wounds had returned to the level of uninjured tissue and superficial wounds. By 21 weeks, NO levels had decreased significantly when compared to superficial wounds (p < 0.01). There were no differences in NO levels between uninjured skin and superficial wounds at any time point (p > 0.05). Conclusions : NO production is similar in late, deep wounds on the female, red Duroc pig to that reported in the literature for human hypertrophic scar further validating this animal model. NO production is quite different after deep wounds as compared to superficial wounds in the FRDP. Early elevation in nitric oxide production might account for excessive inflammation in deep wounds that become thick scars in the FRDP. Nitric oxide regulators and effects at early stages of scar formation should be elucidated further and the FRDP appears to be a useful model.     

Indapamide inhibits endothelium-dependent contractions in the aorta of the spontaneously hypertensive rat

Summary— Experiments were designed to determine whether or not indapamide, an antihypertensive agent with vasodilator properties, inhibits endothelium-dependent contractions. Rings of aortae with and without endothelium from spontaneously hypertensive rats (SHR) were suspended in conventional organ chambers for the measurement of isometric force. Acetylcholine and adenosine diphosphate-β-S in the presence of a nitric oxide synthase inhibitor, caused endothelium-dependent contractions, which were inhibited by indapamide. The compound (10⁻⁴M) also slightly reduced the contractions of rings without endothelium evoked by U-46,619, which activates thromboxane-endoperoxide receptors. These results demonstrate that indapamide inhibits endothelium-dependent contractions in the SHR aorta, and suggest that the inhibition is due, at least in part, to the action of the drug on the hypertensive vascular smooth muscle.     

Clinical and histologic heterogeneity of psoriatic plaques. Therapeutic relevance

Twenty-three patients with resistant psoriasis vulgaris were evaluated clinically and histologically before and after treatment with potent topically administered steroids. It was shown that psoriatic plaques are comprised of clinically and histologically distinct acute and chronic areas, each responding differently to treatment. Chronic areas, characterized by chronic inflammation, respond well to therapy; acute areas, characterized by acute inflammation, are resistant to therapy. It is suggested that the psoriagenic stimulus is greater within the therapy-resistant "hot spots." Future therapy aimed at hot spots may aid in the better control of psoriasis.     

Isolation and characterization of minicell-producing mutants of Shigella spp.

Minicells are small, anucleate cells resulting from aberrant cell divisions at the polar ends of bacilli. We have isolated minicell-producing mutant strains of Shigella flexneri 2a (MC-I) and Shigella dysenteriae 1 (MC-V) after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Microscopically, broth cultures of MC-I and MC-V were found to contain free minicells, normal cells, and filamentous cells with polar, attached minicells. Both strains retained their ability to provoke keratoconjunctivitis in guinea pigs and to invade HeLa cells. Purified suspensions of minicells containing less than one whole cell per 10(6) minicells were obtained by a combination of differential sedimentation and density gradient centrifugation (5 to 30% [wt/vol] linear sucrose gradients). Each MC-I minicell contained about 0.005 times the amount of deoxyribonucleic acid of one normal S. flexneri. The MC-V minicell had about 0.003 times the amount of deoxyribonucleic acid of one whole S. dysenteriae cell. Purified MC-V minicells were treated with polymyxin B to release Shiga toxin. Shiga toxin was readily detected in MC-V minicells by means of a microtiter HeLa cell cytotoxicity assay. Our findings indicate that such a minicell-producing alteration in the cell division cycle of shigellae has not significantly affected their virulence.