The incorporation of [14C]oleic and [14C]linoleic acid into phospholipids and neutral lipids was compared in two recently immortalized airway epithelial cell lines. In addition, the effects of adrenergic stimulation on phospholipid turnover was examined. Both cell lines readily incorporated the fatty acids into all phospholipid and neutral lipid fractions. Isoproterenol (1 microM) induced Ca2+ transients in both cell lines, indicating a functional beta-adrenergic response. Epinephrine (10 microM; 15 min) stimulation of cells prelabeled with [14C]linoleic acid increased the percentage of label in phosphatidylcholine in one cell line. Lipid metabolism can now be extensively studied in human airway epithelia.
Abstract Objective —To determine sensitivity of equine skeletal muscle to tetrodotoxin and compare that with sensitivity of murine and human skeletal muscles. Sample Population —Semimembranosus, vastus lateralis, triceps brachii, and masseter muscle specimens from 22 euthanatized horses, vastus lateralis muscle biopsy specimens from 25 clinically normal humans, and diaphragmatic muscle specimens from 6 mice. Procedure —Electrically elicited twitch responses were measured in muscle specimens incubated in medium alone and with tetrodotoxin (100 n M , 400 n M , 1.6 µ M for equine specimens and 100 n M , 200 n M , 400 n M , 800 nM, 1.6 µ M for murine and human specimens). Percentages of tetrodotoxin-sensitive and -resistant sodium channels were determined and compared among muscles and species. Results —2 sodium channels with different sensitivities to tetrodotoxin were identified in equine muscle. One was blocked with 100 n M tetrodotoxin and the other was unaffected by tetrodotoxin at concentrations up to 1.6 µ M . The only difference detected among the 4 equine muscles was that masseter muscle specimens had a higher percentage of tetrodotoxin- sensitive channels than triceps brachii muscle specimens. Tetrodotoxin-resistant sodium channels constituted 31 to 66% of the equine muscle twitch response, which was greater than that determined for normal human and murine muscle (< 5%). Conclusion and Clinical Relevance —Equine skeletal muscle contains a high percentage of tetrodotoxin-resistant sodium channels. The 4 equine muscles evaluated were more similar to each other than to murine and human muscles. Shifts in expression of sodium channel subtypes may play a role in the manifestation of certain myopathies. ( Am J Vet Res 2000;61:133–138)
Objective Complex regional pain syndrome (CRPS) is a severe chronic pain condition characterized by sensory, autonomic, motor, and dystrophic signs and symptoms. This study was undertaken to expand our current knowledge of the evolution of CRPS signs and symptoms with duration of disease. Method This was a retrospective, cross-sectional analysis using data extracted from a patient questionnaire to evaluate the clinical characteristics of CRPS at different time points of disease progression. Data from the questionnaire included pain characteristics and associated symptoms. It also included autonomic, motor, and dystrophic symptoms and also initiating events, ameliorating and aggravating factors, quality of life, work status, comorbid conditions, pattern of pain spread, family history, and demographics. Comparisons were made of different parameters as they varied with disease duration. Results A total of 656 patients with CRPS of at least 1-year duration were evaluated. The average age of all participants was 37.5 years, with disease duration varying from 1 to 46 years. The majority of participants were white (96%). A total of 80.3% were females. None of the patients in this study demonstrated spontaneous remission of their symptoms. The pain in these patients was refractory showing only modest improvement with most current therapies. Discussion This study shows that although CRPS is a progressive disease, after 1 year, the majority of the signs and symptoms were well developed and although many variables worsen over the course of the illness, the majority demonstrated only moderate increases with disease duration.
