Heterogeneous Ca2+ influx along the adult calyx of held: A structural and computational study

The calyx of Held is a morphologically complex nerve terminal containing hundreds to thousands of active zones. The calyx must support high rates of transient, sound-evoked vesicular release superimposed on a background of sustained release, due to the high spontaneous rates of some afferent fibers. One means of distributing vesicle release in space and time is to have heterogeneous release probabilities (Pr) at distinct active zones, which has been observed at several CNS synapses including the calyx of Held. Pr may be modulated by vesicle proximity to Ca2+ channels, by Ca2+ buffers, by changes in phosphorylation state of proteins involved in the release process, or by local variations in Ca2+ influx. In this study, we explore the idea that the complex geometry of the calyx also contributes to heterogeneous Pr by impeding equal propagation of action potentials through all calyx compartments. Given the difficulty of probing ion channel distribution and recording from adult calyces, we undertook a structural and modeling approach based on computerized reconstructions of calyces labeled in adult cats. We were thus able to manipulate placement of conductances and test their effects on Ca2+ concentration in all regions of the calyx following an evoked action potential in the calyceal axon. Our results indicate that with a non-uniform distribution of Na+ and K+ channels, action potentials do not propagate uniformly into the calyx, Ca2+ influx varies across different release sites, and latency for these events varies among calyx compartments. We suggest that the electrotonic structure of the calyx of Held, which our modeling efforts indicate is very sensitive to the axial resistivity of cytoplasm, may contribute to variations in release probability within the calyx

Synthetic Hydrogel as an Artificial Vitreous Body. A One-Year Animal Study of Its Effects on the Retina

A hydrogel with a high water content was assessed in vitro and in vivo as a possible vitreous substitute. From a large series of polymers produced by the aqueous polymerization of methyl acrylamidoglycolate methyl ether (MAGME), a gel synthesized in 80% water was selected for an animal study. The gel was injected intravitreally into rabbit eyes and followed clinically by ophthalmoscopy, tonometry, and fundus photography. The gel was clinically well tolerated, but after 6 months ophthalmoscopy revealed progressive pallor of the optic nerve head. The eyes were enucleated one year after injection of polymer. Histopathological examination by light microscopy of retinal and vitreal sections revealed significant retinal disorganization, degeneration of the optic nerve and retinal neural elements, retinal detachment, and inflammatory changes. Analysis of immunohistochemically labeled retinal sections revealed loss of ganglion cells and extensive pathological reaction of the Muller cells and astrocytes. All these findings were consistent with a toxic effect of the polymer itself or some residual contaminants. The cytotoxicity of the hydrogel was assessed in vitro using cultured mouse (Balb/c-3T3) fibroblasts. The bioassay showed both cytostatic and cytocidal effects of the polymer. Our results indicate that hydrogels produced from MAGME monomer cannot function as vitreous substitutes because of severe toxic reaction elicited to the posterior segment of the eye

Economic burden of resected (stage IB-IIIA) non-small cell lung cancer in France, Germany and the United Kingdom: A retrospective observational study (LuCaBIS)

OBJECTIVES: New adjuvant treatments are being developed for patients with resected non-small cell lung cancer (NSCLC). Due to scarcity of real-world data available for treatment costs and resource utilization, health technology and cost-effectiveness assessments can be limited. We estimated the burden and cost-of-illness associated with completely resected stage IB-IIIA NSCLC in France, Germany and the United Kingdom (UK). MATERIALS AND METHODS: Eligible patients were aged ≥18 years with completely resected stage IB-IIIA NSCLC between August 2009 and July 2012. Patients (living or deceased) were enrolled at clinical sites by a systematic sampling method. Data were obtained from medical records and patient surveys. Direct, indirect and patient out-of-pocket expenses were estimated by multiplying resource use by country-specific unit costs. National annual costs were estimated based on disease prevalence data available from published sources. RESULTS: 39 centers provided data from 831 patients of whom patient surveys were evaluable in 306 patients. Median follow-up was 26 months. The mean total direct costs per patient during follow-up were: €19,057 (France), €14,185 (Germany), and €8377 (UK). The largest cost drivers were associated with therapies received (€12,375 France; €3694 UK), and hospitalization/emergency costs (€7706 Germany). Monthly direct costs per patient were the highest during the distant metastasis/terminal illness phase in France (€15,562) and Germany (€6047) and during the adjuvant treatment period in the UK (€2790). Estimated mean total indirect costs per patient were: €696 (France), €2476 (Germany), and €1414 (UK). Estimates for the annual national direct cost were €478.4 million (France), €574.6 million (Germany) and €325.8 million (UK). CONCLUSION: To our knowledge, this is the first comprehensive study describing the burden of illness for patients with completely resected stage IB-IIIA NSCLC. The economic burden was substantial in all three countries. Treatment of NSCLC is associated with large annual national costs, mainly incurred during disease progression

Adjuvant treatment patterns and outcomes in patients with stage IB-IIIA non-small cell lung cancer in France, Germany, and the United Kingdom based on the LuCaBIS burden of illness study

OBJECTIVES: To inform health-technology assessments of new adjuvant treatments, we describe treatment patterns in patients with complete resection of stage IB-IIIA non-small cell lung cancer (NSCLC) in France, Germany, and the United Kingdom (UK). MATERIALS AND METHODS: Data were collected via medical record abstraction. Patients were aged ≥18 years with completely resected stage IB-IIIA NSCLC, diagnosed between 01 January 2009 and 31 December 2011. Median follow-up was 26 months. Adjuvant treatment patterns and clinical outcomes were summarized descriptively. RESULTS: Among the 831 patients studied, 239 (29%) had stage IB disease, 179 (22%) had stage IIA disease, 165 (20%) had stage IIB disease, and 248 (30%) had stage IIIA disease. Adjuvant systemic therapy was received by 402 patients (48.4%), (France, 61.8%; Germany, 51.9%; UK, 33.4%). Use of adjuvant therapy increased with increasing stage of disease. Cisplatin/vinorelbine and carboplatin/vinorelbine were the most frequently prescribed adjuvant regimens. Median disease-free survival was 48.0 months (95% confidence interval [CI] 42.3-not estimable); the 25th percentile was 13.2 months (95% CI, 11.0-15.3). 204 patients (24%) died during the follow-up period. The median overall survival was not reached, the 25th percentile was 31.2 months (95% CI 26.8-36.0 months). 272 patients (33%) had disease recurrence during the follow-up period. For 86 of those patients, the first recurrence was local or regional with no distant metastasis and 14 had further progression to metastatic disease during the follow-up time. For the other 186 patients, the first recurrence involved distant metastases. A total of 200 patients had metastatic disease at any time during study follow-up. CONCLUSIONS: Less than half the patients with stage IB-IIIA NSCLC in this observational study received adjuvant systemic therapy. A high rate of first recurrence with distant metastatic disease was observed, emphasising the need for more effective systemic adjuvant therapies in this population

Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse

Asymmetric Excitatory Synaptic Dynamics Underlie Interaural Time Difference Processing in the Auditory System

In order to localize sounds in the environment, the auditory system detects and encodes differences in signals between each ear. The exquisite sensitivity of auditory brain stem neurons to the differences in rise time of the excitation signals from the two ears allows for neuronal encoding of microsecond interaural time differences