Abstract Background context Methylprednisolone (MP) infusion after acute spinal cord injury (SCI) remains controversial despite large randomized studies, including the National Acute Spinal Cord ...Injury Studies (NASCIS). Purpose To determine the effect of NASCIS protocol MP infusion on the expression of ciliary neurotrophic factor (CNTF), a neuroprotective cytokine, in a rat model after SCI. Study design Animal laboratory study. Methods Thirty rats were randomized into an MP infusion group (intravenous IV-MP) versus normal saline (NS) control group (IV-NS) after a standardized SCI. Ciliary neurotrophic factor expression was measured by reverse transcription-polymerase chain reaction at 6, 12, 24, 48, and 72 hours post-SCI. Results Mean CNTF expression was diminished in the MP group at 12 (p=.006) and 24 (p=.008) hours postinjury compared with the control group. Expression of CNTF was not significantly different between the groups at 6, 48, and 72 hours post-SCI. Conclusions Standardized MP infusion post-SCI reduces CNTF activation in a rat SCI model. Further study is needed to determine if this effect is seen in human SCIs.
A rapidly growing literature strongly suggests that exercise, specifically aerobic exercise, may attenuate cognitive impairment and reduce dementia risk. We used PubMed (keywords exercise and ...cognition) and manuscript bibliographies to examine the published evidence of a cognitive neuroprotective effect of exercise. Meta-analyses of prospective studies documented a significantly reduced risk of dementia associated with midlife exercise; similarly, midlife exercise significantly reduced later risks of mild cognitive impairment in several studies. Among patients with dementia or mild cognitive impairment, randomized controlled trials (RCTs) documented better cognitive scores after 6 to 12 months of exercise compared with sedentary controls. Meta-analyses of RCTs of aerobic exercise in healthy adults were also associated with significantly improved cognitive scores. One year of aerobic exercise in a large RCT of seniors was associated with significantly larger hippocampal volumes and better spatial memory; other RCTs in seniors documented attenuation of age-related gray matter volume loss with aerobic exercise. Cross-sectional studies similarly reported significantly larger hippocampal or gray matter volumes among physically fit seniors compared with unfit seniors. Brain cognitive networks studied with functional magnetic resonance imaging display improved connectivity after 6 to 12 months of exercise. Animal studies indicate that exercise facilitates neuroplasticity via a variety of biomechanisms, with improved learning outcomes. Induction of brain neurotrophic factors by exercise has been confirmed in multiple animal studies, with indirect evidence for this process in humans. Besides a brain neuroprotective effect, physical exercise may also attenuate cognitive decline via mitigation of cerebrovascular risk, including the contribution of small vessel disease to dementia. Exercise should not be overlooked as an important therapeutic strategy.
Avascularity and hypoxia result in avascular necrosis and play a negative role in fracture healing. The FDA-approved iron chelating agent, desferoxamine (DFO) in a liquid form, has been shown to ...induce angiogenesis and improve fracture healing through upregulation of the vascular endothelial growth factor. We were concerned that local injection of DFO would either fail to adequately deliver sufficient drug to the desired site or lead to undesired delivery to adjacent sites. Therefore, a sustained release delivery system was desirable to direct DFO to the intended site. Calcium sulfate pellets, collagen sponges, and demineralized cortical bone matrix were all evaluated as potentially controlled release systems for DFO using a fetal mouse metatarsal angiogenesis assay. Angiogenesis was analyzed using a vascularity grading scale, by measuring the mean vessel length of the 5 longest vessels, and by counting the mean number of vessels per metatarsal. Although there was some evidence of angiogenesis with all three carriers, DFO loaded CaSO4 pellets increased vascularity grading, the mean length of the five longest vessels, and the mean number of vessels, all by statistically significant margins versus the control. These results suggest that CaSO4 pellets could be used as a viable, nontoxic, controlled release system for DFO in clinical situations where increased angiogenesis and bone growth are desirable.
Tissue transglutaminase (tTG) catalyzes a Ca
2+-dependent transglutaminase (TGase) activity which cross-links proteins and stabilizes many tissues C.S. Greenberg et al. FASEB J. 5 (1991) 3071. ...Because cartilage is subjected to great stress in vivo, an enzyme that strengthens and stabilizes tissue could play an integral role in maintaining cartilage integrity. The purpose of this study was to determine if active tTG is present in the extracellular matrix (ECM) of adult human osteoarthritic articular cartilage. Using a TGase activity assay along with immunolabeling for tTG of cartilage sections, TGase activity and tTG immunoreactivity were localized in the ECM in cartilage sections, predominantly in the superficial layer. Previous in vitro studies have demonstrated that the Mg-GTP complex inhibits the TGase activity of tTG T.S. Lai et al. J. Biol. Chem. 273 (1998) 1776. To investigate the in situ regulation of the TGase activity of tTG, a TGase activity assay was done with a dose response of GTP, measuring incorporation of fluorescein cadaverine. TGase activity was inhibited by GTP in a similar manner as in vitro. These results not only confirm tTG presence in the ECM, but also indicate tTG as the major TGase activity of the ECM. Secondly, the study provides a possible mechanism by which extracellular tTG is regulated in vivo.
Nucleotides are released by chondrocytes at rest and in response to mechanical stimulation. Extracellular nucleotides are metabolized by a variety of ectoenzymes, producing free phosphate (Pi) or ...pyrophosphate (PPi) and promoting matrix mineralization. Ectoenzymes are differentially localized in cartilage and may be co-released with nucleotides during mechanical stimulation. Extracellular nucleotides can also serve as substrates and/or modulators of enzymes such as tissue transglutaminase and ecto-protein kinases that modify matrix proteins and regulate crystal deposition or growth. Understanding the evolution of osteoarthritis and calcium crystal deposition diseases will require clearer knowledge of the functions of nucleotides and ectoenzymes in the cartilage extracellular matrix.
For studying mechanotransduction in cultured cells, we developed a microplate assay using a fluorescence/luminescence plate reader equipped with software-controlled injectors to deliver a ...reproducible mechanical stimulus (adjustable for both timing and force) and immediately measure adenosine 5
′-triphosphate (ATP) release and calcium mobilization. Suspension or adherent chondrocyte cultures in 96-well plates were incubated with firefly luciferase and luciferin for the ATP assay or loaded with Fluo-3-acetoxy methylester for intracellular calcium measurement. Steady state ATP release was measured in resting cells; then mechanical stimulation was delivered by injection of an equal volume of buffer into the wells. Serial integrations of 20 to 500
ms allowed real-time analysis of the time course of ATP release. Luminescence increased within 500
ms indicating the rapidity of ATP release in chondrocyte mechanotransduction. Subsequent injection of a cell lysis solution allowed quantitation of total cellular ATP as an internal control of cell viability and number. Intracellular calcium was also elevated within 500
ms of fluid injection. This assay is easily adapted for changes in intracellular pH or other ions by use of different commercially available fluorescent indicators. The live-cell assay using fluid injection as a mechanical stimulus is a valuable tool for dissecting the role of signaling pathways in mechanotransduction.
Abstract Background: Pancreatic enzyme replacement therapy (PERT) is essential for maintaining adequate nutrition in children with exocrine pancreatic insufficiency (EPI) due to cystic fibrosis (CF). ...The US Food and Drug Administration regulations now require all PERT products to undergo clinical efficacy and safety studies before they can be considered for marketing approval. Objective: This study was conducted to compare the efficacy of a new formulation of pancrelipase (pancreatin) delayed-release 12,000-lipase unit capsules with placebo in children with EPI due to CF. Methods: This was a multicenter, randomized, double-blind, placebo-controlled, 2-period crossover, superiority study of the new formulation of pancrelipase delayed-release 12,000-lipase unit capsules in children aged 7 to 11 years with CF and EPI. In each period, pancrelipase or identical placebo capsules were taken for 5 days. The primary outcome measure was the coefficient of fat absorption (CFA); secondary outcome measures were the coefficient of nitrogen absorption (CNA) and clinical symptoms. The latter were assessed based on patient-reported daily stool frequency, stool consistency (hard, formed/normal, soft, or watery), flatulence (none, mild, moderate, or severe), and abdominal pain (none, mild, moderate, or severe). Safety measures included vital signs, physical examinations, standard laboratory safety tests (hematology and biochemistry), and adverse events. Results: Seventeen patients were randomized to treatment and 16 completed the study; 1 patient withdrew consent during the first treatment period and was not included in the efficacy analysis. Patients' median age was 8.0 years (range, 7–11 years); 12 patients (70.6%) were male. CFA values were significantly greater for pancrelipase compared with placebo, with least squares mean (SE) values of 82.8% (2.7%) and 47.4% (2.7%), respectively ( P < 0.001). The results were similar for CNA, with mean values of 80.3% (3.2%) and 45.0% (3.2%) ( P < 0.001). Pancrelipase treatment had significantly greater effects on CFA and CNA in patients with a placebo CFA <50% than in those with a placebo CFA >50% (both parameters, P < 0.001 and P = 0.008, respectively). Significant improvements in stool fat, weight, and nitrogen and a significant reduction in daily stool frequency were observed with pancrelipase compared with placebo (all, P < 0.001). Symptoms of EPI were less severe and remained relatively stable during pancrelipase treatment, but worsened slightly during receipt of placebo. Treatment-emergent adverse events were reported in 5 patients (29.4%) during receipt of pancrelipase and in 9 patients (56.3%) during receipt of placebo; these were predominantly gastrointestinal events. There were no discontinuations due to treatment-emergent adverse events and no serious adverse events. Conclusions: In this study in children with EPI due to CF, the new formulation of pancrelipase delayedrelease capsules was associated with improvements in CFA, CNA, stool properties, and EPI symptoms compared with placebo. Pancrelipase delayed-release capsules appeared to be well tolerated. ClinicalTrials.gov identifier: NCT00690820. (Clin Ther.
Abstract Mutations in RAB39B gene have been linked to X-linked early onset Parkinsonism with intellectual disabilities. The aim of this study was to address the genetic contribution of RAB39B to ...Parkinson disease (PD), Dementia with Lewy Bodies (DLB), and pathologically-confirmed Lewy Body Dementia (pLBD) cases. A cohort of 884 PD, 399 DLB and 379 pLBD patients were screened for RAB39B mutations, but no coding variants were found, suggesting RAB39B is not a common cause of PD, DLB or pLBD in Caucasian population.
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