Anterior shear strength of the porcine lumbar spine after laminectomy and partial facetectomy

Degenerative lumbar spinal stenosis is the most common reason for lumbar surgery in patients in the age of 65 years and older. The standard surgical management is decompression of the spinal canal by laminectomy and partial facetectomy. The effect of this procedure on the shear strength of the spine has not yet been investigated in vitro. In the present study we determined the ultimate shear force to failure, the displacement and the shear stiffness after performing a laminectomy and a partial facetectomy. Eight lumbar spines of domestic pigs (7 months old) were sectioned to obtain eight L2–L3 and eight L4–L5 motion segments. All segments were loaded with a compression force of 1,600 N. In half of the 16 motion segments a laminectomy and a 50% partial facetectomy were applied. The median ultimate shear force to failure with laminectomy and partial facetectomy was 1,645 N (range 1,066–1,985) which was significantly smaller (p = 0.012) than the ultimate shear force to failure of the control segments (median 2,113, range 1,338–2,659). The median shear stiffness was 197.4 N/mm (range 119.2–216.7) with laminectomy and partial facetectomy which was significantly (p = 0.036) smaller than the stiffness of the control specimens (median 216.5, 188.1–250.2). It was concluded that laminectomy and partial facetectomy resulted in 22% reduction in ultimate shear force to failure and 9% reduction in shear stiffness. Although relatively small, these effects may explain why patients have an increased risk of sustaining shear force related vertebral fractures after spinal decompression surgery.     

Psychopathology in verified Huntington's disease gene carriers

Huntington's disease is characterized by motor, cognitive, and neuropsychiatric symptoms. This study reviews original research on psychopathology in Huntington's disease that uses standardized instruments in verified gene carriers. Frequently reported neuropsychiatric symptoms are depressed mood, anxiety, irritability, and apathy, with prevalences of 33% to 76%. Obsessive-compulsive symptoms and psychosis occur less often with prevalences of 10% to 52% and 3% to 11%, respectively. Available research provides little insight into the true prevalences of psychopathology in Huntington's disease due to small sample sizes, use of different methodologies, and lack of comparison groups. Future research requires larger cohorts stratified to disease stage, consistent methodologies, and adequate comparison groups.     

Nurses on the move: diversity and the work environment

Over 191 million people make up the international migrant population of today. Their numbers have doubled since 1970, with women now accounting for almost half. The migrant population has been transformed and is changing the very nature of society in both source and destination countries. Greater differences in culture, language, work relationships, and coping mechanisms - in short, greater diversity in society and the workplace - offer many opportunities for excellence in transcultural nursing but also provides fertile ground for discrimination, victimisation, harassment and isolation. This article explores and describes current nurse migration flows, the impact migration has on nurses and the value of positive practice environment for the full integration of international nurses.     

Nurses on the Move: A Global Overview

Objective. To look at nurse migration flows in the light of national nursing workforce imbalances, examine factors that encourage or inhibit nurse mobility, and explore the potential benefits of circular migration.
Principal Findings. The number of international migrants has doubled since 1970 and nurses are increasingly part of the migratory stream. Critical nursing shortages in industrialized countries are generating a demand that is fueling energetic international recruitment campaigns. Structural adjustments in the developing countries have created severe workforce imbalances and shortfalls often coexist with large numbers of unemployed health professionals. A nurse's motivation to migrate is multifactorial, not limited to financial incentives, and barriers exist that discourage or slow the migration process. The migration flows vary in direction and magnitude over time, responding to socioeconomic factors present in source and destination countries. The dearth of data on which to develop international health human resource policy remains. There is growing recognition, however, that migration will continue and that temporary migration will be a focus of attention in the years to come.
Conclusions. Today's search for labor is a highly organized global hunt for talent that includes nurses. International migration is a symptom of the larger systemic problems that make nurses leave their jobs. Nurse mobility becomes a major issue only in a context of migrant exploitation or nursing shortage. Injecting migrant nurses into dysfunctional health systems—ones that are not capable of attracting and retaining staff domestically—will not solve the nursing shortage.     

Reduced incidence of vagally induced atrial fibrillation and expression levels of connexins by n-3 polyunsaturated fatty acids in dogs.

OBJECTIVES: This open-label canine study assessed whether n-3 polyunsaturated fatty acids (PUFAs) prevent vagally induced atrial fibrillation (AF) and influence atrial tissue expression levels of connexins (CXs). BACKGROUND: n-3 polyunsaturated fatty acids in fish oils protect against sudden cardiac death and reduce postoperative AF. Changes in spatial organization of gap junctions or cellular CX levels have been linked to arrhythmogenesis. METHODS: Vagally induced AF was studied. Eight dogs were given fish oil daily for 14 days. Eight control dogs had reproducibly induced AF and were re-evaluated after intravenous administration of fish oil. Atrial fibrillation was compared, and n-3 PUFA, CX40, and CX43 protein levels were assessed in atrial biopsies. RESULTS: Atrial tissue n-3 PUFA levels increased in oral treatment dogs (5.78 +/- 0.71% vs. 2.49 +/- 0.46% in control animals, p < 0.001). No difference was observed for atrial refractory periods or hemodynamic or electrocardiographic parameters. Incidence of AF in oral treatment dogs decreased 79% with the extra stimulus technique (10.5% vs. 48.9%, p = 0.003) and 42% with burst induction (22.5% vs. 38.8%, p = 0.038). Both CX40 and CX43 levels were lower in oral treatment dogs (60% [p = 0.019] and 42% [p = 0.038] lower, respectively); protection against AF was mostly related to reduced CX40 expression levels (p = 0.02). In dogs that were given intravenous n-3 PUFAs, AF inducibility by the extra stimulus technique was reduced from 75.0% to 28.6% (p = 0.002). CONCLUSIONS: Oral treatment with fish oils increased atrial n-3 PUFA levels and reduced vulnerability to induction of AF in this dog model. Modulation of cardiac CX by n-3 PUFAs probably contributes to the antiarrhythmic effects of fish oils.     

Chronic drug infusion into the scala tympani of the guinea pig cochlea.

This research describes a unique, effective and inexpensive delivery system to provide discrete quantities of drugs on a chronic basis to the inner ear. The amount of the drug administered and specific timing of each administration are under investigator control. A micro-injection system mounted atop an animal's head is shown to permit repeated application of agents which effectively block neural responsiveness (tetrodotoxin) on a daily basis for periods up to 2 weeks. Cannulation of the inner ear and chronic delivery of control substances (artificial perilymph) do not affect function. This system may be used to administer drugs to other compartments of the body (e.g., the brain) on a chronic basis for neurophysiologic and neuropharmacologic investigations.