Oxidative inactivation of Actinobacillus actinomycetemcomitans leukotoxin by the neutrophil myeloperoxidase system.

The leukotoxin of Actinobacillus actinomycetemcomitans has been implicated in the pathogenesis of inflammatory periodontal disease. We examined a potential mechanism for detoxification of this microbial product by the neutrophil myeloperoxidase system. Exposure to myeloperoxidase, H2O2, and a halide resulted in marked inactivation of leukotoxin, an effect which required each component of the myeloperoxidase system. Toxin inactivation was blocked by agents which inhibit heme enzymes (azide, cyanide) or degrade H2O2 (catalase). Reagent H2O2 could be replaced by the peroxide-generating enzyme system glucose oxidase plus glucose. The latter system, in fact, was more potent than reagent H2O2 in terms of the capacity to inactivate high concentrations of toxin. Toxin inactivation was complete within 1 to 2 min at 37 degrees C. These observations suggest a possible role for oxidative inactivation of leukotoxin by secretory products of neutrophils.     

Quantitative comparison of magnetic resonance imaging (MRI) and histologic analyses of focal ischemic damage in the rat

Hemispheric swelling and area of infarction, two parameters of cerebral focal ischemic damage, were identified and quantified from T2-weighted magnetic resonance imaging (MRI) two days after occlusion of the middle cerebral artery (MCAO) in spontaneously hypertensive rat (SHR) brains. Results were compared with these measures quantified from 2,3,5-triphenyltetrazolium hydrochloride (TTC)- and hematoxylin and eosin (H&E)-stained histologic sections in the same brains. The degree of hemispheric swelling and infarct size determined by MRI were highly correlated to the measurements as determined in the TTC- and H&E-stained tissues. These results demonstrate that the focal ischemic damaged area and associated tissue swelling identified by MRI is quantitatively similar to, and thus, is representative of actual tissue damage/changes that can be identified by gross or histologic examination.     

Autosomal dominant transmission of isolated congenital vertical talus

We report vertical transmission of isolated congenital vertical talus through three generations of a Honduran family. Five of nine affected family members were examined and the diagnosis was confirmed radiographically. There was incomplete penetrance in one clinically unaffected woman with two affected children. Bilateral and unilateral involvement was seen with a wide range of severity. Based on this family and on cases reviewed from the literature, we propose that isolated congenital vertical talus can be inherited as an autosomal dominant trait with variable expression and incomplete penetrance.     

MEASUREMENT OF NORMAL HUMAN AIRWAYS RESPONSE TO β-ADRENOCEPTOR STIMULATION USING A FORCED OSCILLATION TECHNIQUE

The purpose of the present study was to evaluate the responsiveness of normal human airways to beta-adrenoceptor stimulation using a forced oscillation technique. Seven normal volunteers (aged 25 +/- 2 year) were studied on three occasions, separated by weekly intervals, using a single-blind randomized design. On day 1, subjects were given cumulative doses of inhaled salbutamol (100, 200, 500, 1000 micrograms); and identical placebo was given on the other two visits. Respiratory oscillation impedance (Ros) was measured at baseline and 15 min after each dose increment. The coefficients of variation (CV) for short-term intra-individual variability on each placebo day were 7.5 and 9.5, and 9.6% for long-term variability (measured over all three visits). The 95% confidence values (2SD) for the change in Ros required to exclude natural variability were 0.39, 0.50 and 0.53 cmH2O l-1 s, respectively. There was a small fall in Ros in response to salbutamol although the mean maximum change (0.46 cmH2O l-1 s) was not significant (by ANOVA). Thus, the change in Ros (sensitivity) was no greater than the 95% confidence value for natural variability (reproducibility). Regression analysis also showed no evidence of a dose-response relationship for Ros.     

Regression of melanoma nodules in a patient treated with ranitidine

Human malignant melanoma may regress spontaneously or with immunotherapy, such as Calmette-Guerin bacillus, interferon alfa, interleukin-2, and interleukin-2 plus lymphokine-activated killer cells. Histamine type 2 receptor antagonists can modulate immune function by inhibiting suppressor T-cell induction and activity, and melanoma regressions have been reported after the use of cimetidine with coumarin or interferon alfa. This article describes the complete regression of melanoma nodules in a patient treated with ranitidine hydrochloride, another histamine type 2-receptor antagonist. Ranitidine and cimetidine should be considered to be possibly active immunotherapeutic agents in the design and evaluation of clinical trials.     

Project 2000: perceptions of the philosophy and practice of nursing: shifting perceptions—a new practitioner?

This is the first of two papers which address aspects of the findings of a large scale study commissioned by the English National Board which set out to examine the impact of Project 2000 on perceptions of the philosophy and practice of nursing. The findings presented here suggest that there have been fundamental shifts in perceptions of the nature and discipline of nursing. Students and diplomates of the course perceive themselves as knowledgeable doers, with their practice well grounded in theory and research. They value the interpersonal skills teaching and place the patient firmly at the centre of care delivery, viewing the patient holistically and being prepared to be fierce patient advocates where necessary. It is difficult to determine the extent to which these shifts can be attributed to the Project 2000 course, although the Project 2000 approach to education appears to be an important factor.