Dexamethasone as an adjuvant for peripheral nerve blockade: a randomised,triple-blinded crossover study in volunteers

Background

The efficacy of dexamethasone in extending the duration of local anaesthetic block is uncertain. In a randomised controlled triple blind crossover study in volunteers, we tested the hypothesis that neither i.v. nor perineurally administered dexamethasone prolongs the sensory block achieved with ropivacaine.

Chronic anxiolytic treatment effects on conflict behavior in the rat

The present studies examined the effects of chronic posttest treatment with the antipanic agent alprazolam (ALP) or the traditional anxiolytic agents chlordiazepoxide (CDP) and phenobarbital (PhB) on conflict behavior. In daily ten-minute sessions, water-deprived rats were trained to drink from a tube which was occasionally electrified (0.25 or 0.5 mA). Electrification was signalled by a tone. Chronic ALP (10 mg/kg/day), CDP (40 mg/kg/day), PhB (80 mg/kg/day) or vehicle were injected IP after conflict testing (in some experiments again 12-16 hours later) for a minimum of 6 weeks. Chronic ALP (but not CDP or PhB) resulted in a time-dependent increase in punished responding, with a latency to onset of 3-4 weeks; this effect was not antagonized by the benzodiazepine antagonist Ro15-1788. These data support the hypothesis that conflict paradigms may serve as animal models for the study of antipanic agents. Moreover, these data suggest that not all anxiolytics will exhibit antipanic efficacy.     

Sediment preference in the asiatic clam (Corbicula fluminea) and viviparid snail (Campeloma decisum) as a response to low-level metal and metalloid contamination

Sediment preference experiments were performed with the asiatic clam (Corbicula fluminea) and viviparid snail (Campeloma decisum) to determine the potential use of clam and snail behavior as a response to low-level metal and metalloid contamination. Three sediment types with varying levels of metal contamination were paired in various combinations. Clams and snails were placed in aquaria along the interface between the sediment types. Daily location and burial status were noted for two weeks. Clams spent significantly more days in the uncontaminated sediment when paired with one of the contaminated sediments. Snails spent more days in contaminated sediments when paired with the uncontaminated sediment, but none of these differences was statistically significant. Clams moved fewer days in tanks with the two most contaminated sediment types. Burrowing of snails was relatively unaffected by sediment treatments. The behavior of clams was more sensitive than the behavior of snails to sediment metal contamination. Consequently, clam behavior appears to be a better behavioral indicator of metal contamination.This work was performed under the auspices of the U.S. Department of Energy.     

Kinaesthetic signals and muscle contraction.

Signals generated both peripherally and centrally contribute to the group of sensations termed kinaesthesia. Many experiments report sensations of position and movement under passive relaxed conditions without muscle contraction. However, kinaesthetic acuity is probably of greater functional value when subjects are active rather than passive and, accordingly, movement detection is markedly improved by muscular contraction. One mechanism contributing to this enhancement is likely to involve muscle spindle volleys. When identical microstimulation techniques are applied to skin, joint and muscle spindle endings innervating the hand, some cutaneous afferents and some joint afferents elicit a sensation, but activation of certain other cutaneous afferents and muscle spindle afferents rarely does. Activity in more than one muscle spindle afferent may be required for kinaesthetic sensations, whereas some single cutaneous and joint afferents may have a more 'secure' central projection.     

Critical evaluation of the short "Z" bunionectomy

The authors reviewed 120 "short Z" bunionectomy operations and, on the basis of available clinical and radiographic data, selected 50 osteotomies in 36 patients for review. Follow-up averaged 21 months and ranged from 13 to 26 months. Excellent and good results were found in 92%, while fair and poor results were obtained in 8% of patients. Although seven fractures occurred in the 50 osteotomy sites, most of these resolved without sequellae after appropriate treatment.     

Long-Term Follow-Up of the Changes in Circulating Cytokines, Soluble Cytokine Receptors, and White Blood Cell Subset Counts in Patients with Rheumatoid Arthritis (RA) After Monoclonal Anti-TNFα Antibody Therapy

To investigate the mechanism of the long-lasting efficacy of chimeric monoclonal anti-TNF antibody (cA2) therapy for rheumatoid arthritis (RA), eight patients with refractory RA were treated with a single infusion of cA2 and the changes in circulating cytokines (IL-1, IL-6, TNF, and IL-10), soluble cytokine receptors (TNF-RI, RII, and sIL-6R) and peripheral white blood cell (WBC) subset counts were followed up long-term (12 weeks) after cA2 therapy in them. Significant clinical responses (>20% improvement according to Paulus' criteria) were observed just after cA2 infusion and lasted more than 4 weeks in all patients, as reported elsewhere. Moreover, five of the eight patients showed prolonged clinical responses (>12 weeks). The elevated serum IL-6 and sTNF-RI (or RII) levels before treatment rapidly decreased after treatment. The serum IL-10 levels also significantly elevated before treatment. The elevations of serum IL-10 levels were augmented after treatment and stayed higher than the baseline in four patients with prolonged clinical responses. No significant TNF, IL-1 and -, or sIL-6R were detected in the sera of the patients before treatment and during the whole study period. On the other hand, peripheral lymphocytes as well as total WBC and neutrophils increased for 4 weeks after treatment. However, thereafter, only the lymphocyte count decreased gradually and stayed below the baseline long-term (12 weeks). FACS analysis revealed the predominance of T lymphocytes in the decrease in lymphocyte counts. These results suggest that the augmentation of IL-10 production and the decrease in T cells might partly contribute to the long-lasting efficacy of cA2 treatment in RA.