Uptake of Ca2+ by isolated secretory vesicles from adrenal medulla

Intact secretory vesicles isolated from bovine adrenal medulla contain 94 nmol Na+ per mg of protein, and Ca2+ influx into the vesicles is inhibited by increasing concentrations of extravesicular Na+ (but not of K+, Li+ or choline+) or by addition of the Na+ ionophore monensin. Thus Ca2+ influx is determined by the Na+ gradient across the vesicular membrane. Half maximal inhibition of Ca2+ influx occurs with 34 mM Na+ extravesicularly. The fact that Ca2+ can also be released from the vesicles by inversion of the Na+ gradient provides direct evidence that an Na+-Ca2+ exchange may operate. According to an analysis of the inhibition of Ca2+ uptake by Na+ in a Hill plot 2 Na+ would be exchanged for 1 Ca2+. Ca2+ influx into the vesicles increases with temperature (energy of activation: 16 kcal/mol), can be observed already with 10−7 M free Ca2+ and increases up to 10−4 M Ca2+. Ca2+ influx is not affected by Mg2+ but Sr2+ is inhibitory. Since the process is only slightly influenced by the pH of the incubation medium and is insensitive to Mg2+-ATP or inhibitors of the proton translocating Mg2+-ATPase the electrochemical proton gradient across the vesicular membrane does not affect directly the Ca2+ influx into the secretory vesicles. Ca2+ uptake is insensitive to ruthenium red and oligomycin

Repeated lung volume reduction surgery is successful in selected patients†

OBJECTIVES Lung volume reduction surgery (LVRS) improves dyspnoea, quality of life and may even prolong survival in carefully selected patients with end-stage emphysema. The benefit may be sustained for several years and vanishes with the natural progression of the disease. Data on repeated surgical treatment of emphysema are scarce. The aim of this study was to evaluate the safety, effects and outcomes of repeated LVRS (Re-LVRS) in patients no longer benefiting from their initial LVRS. METHODS Between June 2002 and December 2013, 22 patients (9 females) with advanced emphysema underwent Re-LVRS at a median of 60 months (25-196) after their initial LVRS. While initial LVRS was performed thoracoscopically as a bilateral procedure, Re-LVRS was performed unilaterally by a video-assisted thoracoscopic technique in 19 patients and, due to adhesions, by thoracotomy in 3 patients. Pulmonary function test (PFT) was performed at 3 and 12 months postoperatively. RESULTS Lung function at Re-LVRS was similar to that prior to the first LVRS. The 90-day mortality rate was 0%. The first patient died 15 months postoperatively. The median hospitalization time after Re-LVRS was significantly longer compared with the initial LVRS [14 days, interquartile range (IQR): 11-19, vs 9 days, IQR: 8-14; P = 0.017]. The most frequent complication was prolonged air leak with a median drainage time of 11 days (IQR: 6-13); reoperations due to persistent air leak were necessary in 7 patients (32%). Five patients (23%) had no complications. Lung function and Medical Research Council (MRC) score improved significantly for up to 12 months after Re-LVRS, with results similar to those after initial bilateral LVRS. The average increase in the forced expiratory volume in 1 s (FEV1) was 25% (a 7% increase over the predicted value or 0.18 l) at 3 months, and the mean reduction in hyperinflation, assessed by relative decrease in RV/TLC (residual volume/total lung capacity), was 12% at 3 months (a decrease of 8% in absolute ratios). The mean MRC breathlessness score decreased significantly after 3 months (from 3.7 to 2.2). CONCLUSIONS Re-LVRS can be performed successfully in carefully selected patients as a palliative treatment. It may be performed as a bridge to transplantation or in patients with newly diagnosed intrapulmonary nodules or during elective cardiac surgery. Morbidity is acceptable and outcomes may be satisfactory with significantly improved lung function and reduced dyspnoea for at least 12 months postoperativel

Effects of Monovalent and Divalent Cations on Ca2+ Fluxes Across Chromaffin Secretory Membrane Vesicles

Abstract: Bovine chromaffin secretory vesicle ghosts loaded with Na+ were found to take up Ca2+ when incubated in K+ media or in sucrose media containing micromolar concentrations of free Ca2+. Li+- or choline+loaded ghosts did not take up Ca2+. The Ca2+ accumulated by Na+-loaded ghosts could be released by the Ca2+ ionophore A23187, but not by EGTA. Ca2+ uptake was inhibited by external Sr2+, Na +, Li +, or choline +. All the 45Ca2+ accumulated by Na+-dependent Ca2+ uptake could be released by external Na +, indicating that both Ca2+ influx and efflux occur in a Na+-dependent manner. Na + -dependent Ca2+ uptake and release were only slightly inhibited by Mg2+. In the presence of the Na+ ionophore Monensin the Ca2+ uptake by Na +-loaded ghosts was reduced. Ca2+ sequestered by the Na+-dependent mechanism could also be released by external Ca2+ or Sr2+ but not by Mg2+, indicating the presence of a Ca2+/Ca2+ exchange activity in secretory membrane vesicles. This Ca2+/Ca2+ exchange system is inhibited by Mg2+, but not by Sr2+. The Na + -dependent Ca2+ uptake system in the presence of Mg2+ is a saturable process with an apparent Km of 0.28 μM and a Vmax= 14.5 nmol min−1 mg protein−1. Ruthenium red inhibited neither the Na+/Ca2+ nor the Ca2+/Ca2+ exchange, even at high concentrations

Feasibility of Photofrin II as a radiosensitizing agent in solid tumors - Preliminary results

Background: Photofrin II has been demonstrated to serve as a specific and selective radiosensitizing agent in in vitro and in vivo tumor models. We aimed to investigate the feasibility of a clinical application of Photofrin II. Material and Methods: 12 patients were included in the study (7 unresectable solid tumors of the pelvic region, 3 malignant gliomas, 1 recurrent oropharyngeal cancer, 1 recurrent adenocarcinoma of the sphenoid sinus). The dose of ionizing irradiation was 30-50.4 Gy; a boost irradiation of 14 Gy was added for the pelvic region. All patients were intravenously injected with 1 mg/kg Photofrin II 24 h prior to the commencement of radiotherapy. Magnetic resonance imaging (MRI) controls and in some cases positron emission tomography (PET) were performed in short intervals. The mean follow-up was 12.9 months. Results: No major adverse events were noted. Minor adverse events consisted of mild diarrhea, nausea and skin reactions. A complete remission was observed in 4/12 patients. A reduction in local tumor volume of > 45% was achieved in 4/12 patients. Stable disease was observed in 4/12 patients. 1 patient showed local disease progression after 5 months. Conclusion: The early follow-up results are encouraging regarding the feasibility of the application of Photofrin II as a radiosensitizing agent

Propensity matched comparison of extrapleural pneumonectomy and pleurectomy/decortication for mesothelioma patients

OBJECTIVES: The objective of this retrospective study was to assess perioperative outcomes, overall survival and freedom from recurrence after induction chemotherapy followed by extrapleural pneumonectomy (EPP) or pleurectomy/decortication (P/D) in patients with mesothelioma in a propensity score matched analysis. METHODS: Between September 1999 and August 2015, 167 patients received multimodality treatment (platinum-based chemotherapy followed by EPP [n = 141] or P/D [n = 26]). We performed 2:1 propensity score matching for gender, laterality, epithelioid histological subtype and International Mesothelioma Interest Group (iMig) stage (52 EPP and 26 P/D). RESULTS: Postoperative major morbidity (48% vs 58%, P = 0.5) was similar in both groups; however, the complication profile and severity were different and favoured P/D; the 90-day mortality (8% vs 0%, P = 0.3) rate was lower in P/D although not statistically significant. Prolonged air leak (≥10 days) occurred in 15 patients (58%) undergoing P/D. The intensive care unit stay was significantly longer after EPP (P = 0.001). Freedom from recurrence was similar for both groups (EPP: median 15 months, 95% confidence interval [CI]: 10–21; P/D: 13 months, 95% CI: 11–17) (P = 0.2). Overall survival was significantly longer for patients undergoing P/D (median 32 months, 95% CI: 29–35) compared to EPP (23 months, 95% CI: 21–25) (P = 0.031), but in the P/D group many cases were censored (73%) and the follow-up time was relatively short. CONCLUSIONS: P/D and EPP seem to have similar rates of major morbidity, although the profile of complications is different and more severe after EPP. Freedom from recurrence is comparable in both groups whereas improved overall survival needs to be confirmed in a large patient group with longer follow-up

ADC histograms predict response to anti-angiogenic therapy in patients with recurrent high-grade glioma.

INTRODUCTION The purpose of this study is to evaluate apparent diffusion coefficient (ADC) maps to distinguish anti-vascular and anti-tumor effects in the course of anti-angiogenic treatment of recurrent high-grade gliomas (rHGG) as compared to standard magnetic resonance imaging (MRI). METHODS This retrospective study analyzed ADC maps from diffusion-weighted MRI in 14 rHGG patients during bevacizumab/irinotecan (B/I) therapy. Applying image segmentation, volumes of contrast-enhanced lesions in T1 sequences and of hyperintense T2 lesions (hT2) were calculated. hT2 were defined as regions of interest (ROI) and registered to corresponding ADC maps (hT2-ADC). Histograms were calculated from hT2-ADC ROIs. Thereafter, histogram asymmetry termed "skewness" was calculated and compared to progression-free survival (PFS) as defined by the Response Assessment Neuro-Oncology (RANO) Working Group criteria. RESULTS At 8-12 weeks follow-up, seven (50%) patients showed a partial response, three (21.4%) patients were stable, and four (28.6%) patients progressed according to RANO criteria. hT2-ADC histograms demonstrated statistically significant changes in skewness in relation to PFS at 6 months. Patients with increasing skewness (n = 11) following B/I therapy had significantly shorter PFS than did patients with decreasing or stable skewness values (n = 3, median percentage change in skewness 54% versus -3%, p = 0.04). CONCLUSION In rHGG patients, the change in ADC histogram skewness may be predictive for treatment response early in the course of anti-angiogenic therapy and more sensitive than treatment assessment based solely on RANO criteria

Transcriptomic analysis of crustacean neuropeptide signaling during the moult cycle in the green shore crab, Carcinus maenas

Abstract Background Ecdysis is an innate behaviour programme by which all arthropods moult their exoskeletons. The complex suite of interacting neuropeptides that orchestrate ecdysis is well studied in insects, but details of the crustacean ecdysis cassette are fragmented and our understanding of this process is comparatively crude, preventing a meaningful evolutionary comparison. To begin to address this issue we identified transcripts coding for neuropeptides and their putative receptors in the central nervous system (CNS) and Y-organs (YO) within the crab, Carcinus maenas, and mapped their expression profiles across accurately defined stages of the moult cycle using RNA-sequencing. We also studied gene expression within the epidermally-derived YO, the only defined role for which is the synthesis of ecdysteroid moulting hormones, to elucidate peptides and G protein-coupled receptors (GPCRs) that might have a function in ecdysis. Results Transcriptome mining of the CNS transcriptome yielded neuropeptide transcripts representing 47 neuropeptide families and 66 putative GPCRs. Neuropeptide transcripts that were differentially expressed across the moult cycle included carcikinin, crustacean hyperglycemic hormone-2, and crustacean cardioactive peptide, whilst a single putative neuropeptide receptor, proctolin R1, was differentially expressed. Carcikinin mRNA in particular exhibited dramatic increases in expression pre-moult, suggesting a role in ecdysis regulation. Crustacean hyperglycemic hormone-2 mRNA expression was elevated post- and pre-moult whilst that for crustacean cardioactive peptide, which regulates insect ecdysis and plays a role in stereotyped motor activity during crustacean ecdysis, was elevated in pre-moult. In the YO, several putative neuropeptide receptor transcripts were differentially expressed across the moult cycle, as was the mRNA for the neuropeptide, neuroparsin-1. Whilst differential gene expression of putative neuropeptide receptors was expected, the discovery and differential expression of neuropeptide transcripts was surprising. Analysis of GPCR transcript expression between YO and epidermis revealed 11 to be upregulated in the YO and thus are now candidates for peptide control of ecdysis. Conclusions The data presented represent a comprehensive survey of the deduced C. maenas neuropeptidome and putative GPCRs. Importantly, we have described the differential expression profiles of these transcripts across accurately staged moult cycles in tissues key to the ecdysis programme. This study provides important avenues for the future exploration of functionality of receptor-ligand pairs in crustaceans

Effect of Polyphenols on Oxidative Stress and Mitochondrial Dysfunction in Neuronal Death and Brain Edema in Cerebral Ischemia

Polyphenols are natural substances with variable phenolic structures and are elevated in vegetables, fruits, grains, bark, roots, tea, and wine. There are over 8000 polyphenolic structures identified in plants, but edible plants contain only several hundred polyphenolic structures. In addition to their well-known antioxidant effects, select polyphenols also have insulin-potentiating, anti-inflammatory, anti-carcinogenic, anti-viral, anti-ulcer, and anti-apoptotic properties. One important consequence of ischemia is neuronal death and oxidative stress plays a key role in neuronal viability. In addition, neuronal death may be initiated by the activation of mitochondria-associated cell death pathways. Another consequence of ischemia that is possibly mediated by oxidative stress and mitochondrial dysfunction is glial swelling, a component of cytotoxic brain edema. The purpose of this article is to review the current literature on the contribution of oxidative stress and mitochondrial dysfunction to neuronal death, cell swelling, and brain edema in ischemia. A review of currently known mechanisms underlying neuronal death and edema/cell swelling will be undertaken and the potential of dietary polyphenols to reduce such neural damage will be critically reviewed