Quantification of plant cell coupling with three-dimensional photoactivation microscopy

Plant cells are directly connected by plasmodesmata that form channels through the cell wall and enable the intercellular movement of cytosolic solutes, membrane lipids and signalling molecules. Transport through plasmodesmata is regulated not only by a fixed size-exclusion limit, but also by physiological and pathological adaptation. To understand plant cell communication, carbon allocation and pathogen attack, the capacities for a specific molecule to pass a specific cell-wall interface is an essential parameter. So far, the degree of cell coupling was derived from frequency and diameter of plasmodesmata in relevant tissues as assessed by electron microscopy of fixed material. However, plasmodesmata functionality and capacity can only be determined in live material, not from electron microscopy, which is static and prone to fixation artefacts. Plasmodesmata functionality was a few times assessed using fluorescent tracers with diffusion properties similar to cytosolic solutes. Here, we used three-dimensional photoactivation microscopy to quantify plasmodesmata-mediated cell-wall permeability between living Cucurbita maxima leaf mesophyll cells with caged fluorescein as tracer. For the first time, all necessary functional and anatomical data were gathered for each individual cell from three-dimensional time series. This approach utilized a confocal microscope equipped with resonant scanner, which provides the high acquisition speed necessary to record optical sections of whole cells and offers time resolution high enough to follow the kinetics of photoactivation. The results were compared to two-dimensional measurements, which are shown to give a good estimate of cell coupling adequate for homogenous tissues. The two-dimensional approach is limited whenever tissues interfaces are studied that couple different cell types with diverse cell geometries.

Endothelial function assessment: flow-mediated dilation and constriction provide different and complementary information on the presence of coronary artery disease

AIMS

A number of risk factors for atherosclerosis have been identified, but it remains difficult, on an individual patient basis, to predict how these factors interact in determining the development of coronary artery disease (CAD). It also remains unclear whether the study of endothelial function provides information that is additive to that of traditional risk factors.

METHODS AND RESULTS

Flow-mediated dilation (FMD) and low-flow-mediated constriction (L-FMC) were measured in 451 consecutive patients before coronary angiography. Low-flow-mediated constriction (P< 0.0001) and FMD (P=0.0005) progressively decreased with the number of diseased vessels, and L-FMC showed a significant linear correlation with the SYNTAX score (R=0.38; P< 0.0001). Logistic regression analysis confirmed the association between endothelial function parameters and CAD (P=0.001 for L-FMC, P=0.02 for FMD). Receiver operating characteristic analysis demonstrated that the addition of L-FMC alone and of the combination of FMD and L-FMC improved the predictive power of a model based on traditional risk factors for CAD (area under the curve of the risk factor model=0.716; risk factor model + FMD=0.734, P=0.1 compared with risk factor model; risk factor model + L-FMC=0.771, P=0.004; risk factor model + L-FMC + FMD=0.779, P=0.002). Reclassification statistics showed that the introduction of FMD to the model based on the traditional risk factors correctly reclassified an additional 5% of patients, and that the introduction of L-FMC net correctly reclassified 19% of the patients. There was no correlation between different parameters of endothelial function.

CONCLUSION

Endothelial function assessment provides modest but statistically significant additional information in predicting the presence of CAD.

Noninvasive vascular function measurement in the community: cross-sectional relations and comparison of methods

BACKGROUND

Several methods of noninvasive vascular function testing have been suggested for cardiovascular risk screening in the community. A direct comparison of the different methods and their relation to classical cardiovascular risk factors in a large cohort is missing.

METHODS AND RESULTS

In 5000 individuals (mean age, 55.5 ± 10.9 years; age range, 35 to 74 years; women, 49.2%) of the population-based Gutenberg Heart Study, we performed simultaneous measurement of flow-mediated dilation (FMD) and peripheral arterial volume pulse determined by infrared photo (reflection index) and pneumatic plethysmography (PAT) and explored their associations. All function measures were recorded at baseline and after reactive hyperemia induced by 5-minute brachial artery occlusion. Correlations between different measures of vascular function were statistically significant but moderate. The strongest association for hyperemic response variables was observed for PAT ratio and FMD (Spearman r = 0.17; age- and sex-adjusted partial correlation, 0.068). Classical risk factors explained between 15.8% (baseline reflection index) and 58.4% (brachial artery diameter) of the baseline values but only accounted for 3.2% (reflection index), 15.4% (FMD), and 13.9% (PAT ratio) of the variability of reflective hyperemic response. Regression models varied in their relations to classical risk factors for the individual vascular function measures. Consistently associated with different vascular function methods were age, sex, body mass index, and indicators of hypertension. Peripheral tonometry also showed a relation to fasting glucose concentrations.

CONCLUSIONS

Noninvasive measures of conduit artery and peripheral arterial function are modestly correlated, differ in their relation to classical cardiovascular risk factors, and may thus reflect different pathologies.

Reliability and cost-effectiveness of complete lymph node dissection under tumescent local anaesthesia vs. general anaesthesia: a retrospective analysis in patients with malignant melanoma AJCC stage III

BACKGROUND

Complete lymph node dissection (CLND) in melanoma patients with a positive sentinel lymph node (SLN) is currently being debated, as it is a cost-intensive surgical intervention with potentially high morbidity.

OBJECTIVE

This clinical study seeks to clarify the effectiveness, reliability and cost-effectiveness of CLND performed under tumescent local anaesthesia (TLA) compared with procedures under general anaesthesia (GA).

METHODS

We retrospectively analysed the data from 60 patients with primary malignant melanoma American Joint Committee on Cancer stage III who underwent CLND.

RESULTS

Altogether 26 (43.3%) patients underwent CLND under TLA and 34 (56.7%) patients underwent CLND under GA. Fifteen of 43 (34.9%) patients had a complication, such as development of seromas and/or wound infections. The rate of complications was 25.0% (3/12) in the axilla subgroup and 28.6% (4/14) in the groin subgroup of the TLA group. In the GA group, the complication rate was 31.3% (5/16) in the axilla subgroup and 44.4% (8/18) in the groin subgroup. The costs for CLND were significantly less for the CLND in a procedure room performed under TLA (mean €67.26) compared with CLND in an operating room under GA (mean €676.20, P < 0.0001).

CONCLUSIONS

In conclusion, this study confirms that TLA is an excellent, safe, effective and cost-efficient alternative to GA for CLND in melanoma patients.

Association of serum procalcitonin with cardiovascular prognosis in coronary artery disease

BACKGROUND

Procalcitonin (PCT) is an established biomarker for the diagnosis of sepsis. Evidence is growing that PCT concentration correlates with the extent of atherosclerosis and prognosis in patients with coronary artery disease (CAD).

METHODS AND RESULTS

A total of 2,131 patients with CAD were followed up for a median of 3.6 years. During follow-up, death from cardiovascular causes was registered in 95 patients and non-fatal myocardial infarction in 85 patients. Median and quartile 1 and 3 are reported for PCT concentration. Patients who died of cardiovascular causes had higher PCT concentrations [0.021 (0.012/0.036) ng/ml vs. 0.015 (0.010/0.023) ng/ml; P<0.0001]. Patients with acute coronary syndrome had increased concentrations of PCT in relation to patients with stable angina [0.016 (0.011/0.027) ng/ml vs. 0.014 (0.009/0.014) ng/ml; P for trend <0.0001]. PCT concentration across quartiles was associated with the event rate (P=0.026; log-rank test) and mortality (P=0.00018). On Cox regression analysis, elevated PCT concentration was related to cardiovascular mortality [hazard ratio (HR), 1.34; 95% confidence interval (CI): 1.08-1.65, P=0.0070], but not to cardiovascular events (HR, 1.09; 95%CI: 0.93-1.28, P=0.28). After adjustment for C-reactive protein (CRP), PCT did not provide additional prognostic information.

CONCLUSIONS

PCT is associated with future cardiovascular mortality in patients with CAD, but PCT is not superior to CRP for prediction of outcome.

High-Performance Barrier Layers for Flexible CIGS Thin-Film Solar Cells on Metal Foils

Cu(In, Ga)Se2 (CIGS) solar cells have been fabricated on different metal foil substrates. Preferred foils with regard to costs and physical properties were stainless steel, titanium and Kovar® (Fe/Ni/Co alloy). SiOx films prepared by PECVD and sol/gel methods were deposited as barrier layers on these metal foil substrates. Both film types showed good suitability as diffusion barriers for substrate elements. In the SiOx:Na (sol/gel) barrier sodium could be incorporated to provide the Na-supply to the CIGS absorber. With relatively low sodium concentrations in these films (6% Na2O) large amounts of Na in the absorber have been found. Using a combination of SiOx (PECVD) and SiOx:Na (sol/gel) layers AM 1.5 cell efficiencies of 13.1% on titanium foil substrates have been achieved. With a newly implemented insulation test based on electrolysis measurements pinholes in the barrier layers could be localized and conclusions on their origin could be drawn.

Effects of crop rotation and reduced nitrogen fertilisation on Apera spica-venti populations in a long-term experiment

Apera spica-venti is one of the most serious annual grass weeds in Germany and may cause considerably yield losses in untreated fields. A long-term field experiment was conducted investigating the effects of crop rotation and nitrogen fertiliser use on A. spica-venti populations. A six-field cash-crop rotation with 67% winter cereals and a six-field fodder crop rotation with 50% winter cereals were studied. The rate of tillering was in the fodder crop rotation significantly higher than in the cash crop rotation. The halving of nitrogen fertilizer dose caused a significant increase in the tillering rate. Most plants of A. spica-venti emerged in winter wheat. There was an increase of emerged A. spica-venti in winter wheat from year to year.

Multiple marker approach to risk stratification in patients with stable coronary artery disease

AIMS

multimarker approaches for risk prediction in coronary artery disease have remained inconsistent. We assessed multiple biomarkers representing distinct pathophysiological pathways in relation to cardiovascular events in stable angina.

METHODS AND RESULTS

we investigated 12 biomarkers reflecting inflammation [C-reactive protein, growth-differentiation factor (GDF)-15, neopterin], lipid metabolism (apolipoproteins AI, B100), renal function (cystatin C, serum creatinine), and cardiovascular function and remodelling [copeptin, C-terminal-pro-endothelin-1, mid-regional-pro-adrenomedullin (MR-proADM), mid-regional-pro-atrial natriuretic peptide (MR-proANP), N-terminal-pro-B-type natriuretic peptide (Nt-proBNP)] in 1781 stable angina patients in relation to non-fatal myocardial infarction and cardiovascular death (n = 137) over 3.6 years. Using Cox proportional hazards models and C-indices, the strongest association with outcome for log-transformed biomarkers in multivariable-adjusted analyses was observed for Nt-proBNP [hazard ratio (HR) for one standard deviation increase 1.65, 95% confidence interval (CI) 1.28-2.13, C-index 0.686], GDF-15 (HR 1.59, 95% CI 1.25-2.02, C-index 0.681), MR-proANP (HR 1.46, 95% CI 1.14-1.87, C-index 0.673), cystatin C (HR 1.39, 95% CI 1.10-1.75, C-index 0.671), and MR-proADM (HR 1.63, 95% CI 1.21-2.20, C-index 0.668). Each of these top single markers and their combination (C-index 0.690) added predictive information beyond the baseline model consisting of the classical risk factors assessed by C-index and led to substantial reclassification (P-integrated discrimination improvement <0.05).

CONCLUSION

comparative analysis of 12 biomarkers revealed Nt-proBNP, GDF-15, MR-proANP, cystatin C, and MR-proADM as the strongest predictors of cardiovascular outcome in stable angina. All five biomarkers taken separately offered incremental predictive ability over established risk factors. Combination of the single markers slightly improved model fit but did not enhance risk prediction from a clinical perspective.