To examine the effect of chronically elevated CO(2) on excitability and function of neurons, we exposed mice to 8 and 12% CO(2) for 4 wk (starting at 2 days of age), and examined the properties of freshly dissociated hippocampal neurons obtained from slices. Chronic CO(2)-treated neurons (CC) had a similar input resistance (R(m)) and resting membrane potential (V(m)) as control (CON). Although treatment with 8% CO(2) did not change the rheobase (64 +/- 11 pA, n = 9 vs. 47 +/- 12 pA, n = 8 for CC 8% vs. CON; means +/- SE), 12% CO(2) treatment increased it significantly (73 +/- 8 pA, n = 9, P = 0.05). Furthermore, the 12% CO(2) but not the 8% CO(2) treatment decreased the Na(+) channel current density (244 +/- 36 pA/pF, n = 17, vs. 436 +/- 56 pA/pF, n = 18, for CC vs. CON, P = 0.005). Recovery from inactivation was also lowered by 12% but not 8% CO(2). Other gating properties of Na(+) current, such as voltage-conductance curve, steady-state inactivation, and time constant for deactivation, were not modified by either treatment. Western blot analysis showed that the expression of Na(+) channel types I-III was not changed by 8% CO(2) treatment, but their expression was significantly decreased by 20-30% (P = 0.03) by the 12% treatment. We conclude from these data and others that neuronal excitability and Na(+) channel expression depend on the duration and level of CO(2) exposure and maturational changes occur in early life regarding neuronal responsiveness to CO(2). 相似文献
HSS Journal ® - Hip hemiarthroplasty is a well-established treatment of displaced femoral neck fracture, although debate exists over whether cemented or uncemented fixation is superior.... 相似文献
The study evaluated the hepatoprotective activity of plant extracts of cinnamon and glycyrrhizin in distinct dosage ways to minimize the oxidative stress induced by carbon tetrachloride (CCl4) in BALB/cJ inbred albino mice. Fifteen albino mice were divided into five groups, each group containing three mice. Group A was referred as positive control while group B, C, D and E were injected intraperitoneally with 1 mL/kg body weight of CCl4 twice a week for 1 month. Group C and D were treated orally with isolated extracts of cinnamon @50 mg/kg and glycyrrhizin @50 mg/kg respectively on daily basis for 1 month. However, group E was treated orally with combination dose of cinnamon @50 mg/kg + glycyrrhizin @50 mg/kg body weight. The increase in the levels of alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP), triglyceride (TG), malondialdehyde (MDA) and glucose were recorded in CCl4 induced liver injury in mice while there is decrease in the levels of total protein (TP), reduced glutathione (GSH), Superoxide dismutase (SOD) and catalase (CAT) in CCL4 intoxicated mice. Isolated therapy of plant extracts of cinnamon and glycyrrhizin decreased the levels of ALT, AST, ALP, MDA, TG and glucose whereas increase in TP, GSH, SOD and CAT was observed in plant extracts treated mice. The best restoration of all the above said parameters near to control was observed in group of mice treated with combination dose of cinnamon and glycyrrhizin @50 mg/kg. Therefore, the present study declared the antioxidative, anti-inflammatory and hepatoprotective activity of standardized extracts of cinnamon and glycyrrhizin and their potent defensive property.
A retrospective analysis of 25 Arab patients with juvenile dermatomyositis (JDMS) was conducted between 1988 and 1996. The mean age at disease onset was 8.25 years (range 1.5-15 yrs) with a male: female ratio of 1.5:1. The disease duration before diagnosis was 1-108 months. Two patients had a family history of JDMS. The clinical features included fever in 14 patients (56%), weight loss in 20 (80%), muscle weakness in all 25 (100%), and muscle pain in 14 (56%). Skin lesions included Gottron's papules in 15 patients (60%), heliotrope in 13 (52%), erythematous malar rash in 8 (32%), and pigmentary changes in 12 (48%). Seventeen of the 25 patients had arthralgia (68%) and 16 patients had arthritis (64%). Gastrointestinal symptoms were noted in 19 patients (76%). Myocarditis with cardiac failure was the initial presentation of 1 patient, while 2 had conduction defect. Twelve patients (48%) had respiratory symptoms. The course of the disease was complicated by calcinosis in 10 patients (40%). All of the patients were treated with prednisone; 15 were also treated with methotrexate. The duration of follow up ranged from 6-108 months (mean 54.5 months). Twenty-three patients improved, including those who had calcinosis at the time of presentation, with a current muscle power of 4/5 in 10 patients (40%) and 5/5 in 13 patients (52%). No deaths were reported in our series and no patients are currently bedridden. 相似文献