Indicator Of Membrane Integrity Research Articles

Analyzing the correlation between body composition variables and cellular phase angle via computerized bioelectrical impedance analysis (BIA)

Background: Various diseases and pathological conditions, as well as inflammatory processes, either in isolation or in combination with advanced age, can lead to significant alterations in body composition. This study investigates the correlation between various body composition metrics and the cellular Phase Angle (PhA) through Computerized Bioelectrical Impedance Analysis (BIA) in a diverse age group of individuals ranging from 18 to 80 years. Objective: Our aim was to explore the interplay between body composition variables such as Body Mass Index, Lean Body Mass, Skeletal Muscle Mass, and their potential influence on the cellular integrity as indicated by PhA. Methods: Utilizing a dataset of 199 participants, we employed both linear and advanced machine learning models, including Random Forest regression, to analyze the predictive relationships and variable importance within our body composition metrics. Results: Initial analyses revealed strong correlations between mass-related measures and suggested complex relationships with the PhA, an indicator of cellular health and membrane integrity. The Random Forest model significantly outperformed simple linear regression in predicting PhA, emphasizing the nonlinear nature of these relationships and the importance of a comprehensive approach in body composition assessment. Conclusion: Our findings highlight the nuanced interactions between body composition variables and their collective impact on cellular health as measured by PhA. This study underscores the potential of utilizing PhA alongside traditional metrics for a more nuanced understanding of body composition and its implications for health. Future research should continue to leverage advanced statistical and machine learning techniques to further elucidate these complex relationships, with implications for nutritional, sports medicine, and biomedical fields. Initial analyses revealed strong correlations between mass-related measures and suggested complex relationships with the Phase Angle, an indicator of cellular health and membrane integrity. The Random Forest model significantly outperformed simple linear regression in predicting PhA, emphasizing the nonlinear nature of these relationships and the importance of a comprehensive approach in body composition assessment. Our findings highlight the nuanced interactions between body composition variables and their collective impact on cellular health as measured by PhA. This study underscores the potential of utilizing PhA alongside traditional metrics for a more nuanced understanding of body composition and its implications for health. Future research should continue to leverage advanced statistical and machine learning techniques to further elucidate these complex relationships, with implications for nutritional, sports medicine, and biomedical fields.

Diagnostic and prognostic utility of phase angle in patients with cancer.

Patients with cancer experience dynamic and longitudinal changes in nutritional status and body composition along the disease trajectory. They often want to know about their outlook with regard to treatment outcomes and overall survival. One of the commonly used measures for body composition is bioelectrical impedance analysis (BIA). BIA is an easy-to-use, quick, inexpensive, noninvasive, and reproducible technique that is often incorporated in daily clinical practice. Phase angle (PA), which is derived from BIA, is an indicator of cell membrane health and integrity. Higher PA values reflect better cell function, higher muscle mass, and lower fat mass. PA is also thought to be a proxy of water distribution (ratio between extracellular water [ECW] and intracellular water [ICW]) and body cell mass. In this narrative review, we discuss studies examining the diagnostic and prognostic value of PA regarding nutritional status, body composition and physical function, complications of cancer treatments, overall survival, symptoms, and quality of life (QOL) in patients with cancer. The literature suggests that PA is moderately to strongly correlated with body composition and physical function but only weakly correlated with nutritional status, complications, survival, symptoms, and QOL. Furthermore, the PA cutoff values vary significantly according to study and patient population with the diversity of bioelectrical impedance technology and electrode composition and placement. Thus, PA has yet to be routinely incorporated into clinical practice for patients with cancer. Future research is needed to determine how to translate scientific understanding of PA to clinical practice.

Effect Of Acute Feeding On Raw Bioimpedance Values And Body Water Estimates In Healthy Adults

Raw bioimpedance values of resistance (R), reactance (Xc), impedance (Z), and phase angle (PhA) are indicators of cell hydration, health, and membrane integrity. There is increasing interest in using these values as indicators of hydration and nutritional status, but effects of acute nutritional intake on raw bioimpedance values is currently unknown. PURPOSE: To determine the effects of acute feeding on raw bioimpedance values and derived body water estimates (total body water [TBW], extracellular water [ECW], intracellular water [ICW]) obtained from multi-frequency bioelectrical impedance spectroscopy (BIS). METHODS: Twenty-nine healthy young adults (59% Female; Age: 21.3 ± 2.7 yrs; Height: 172.5 ± 9.2 cm; Weight: 71.2 ± 10.3 kg) completed three randomly assigned feeding conditions: high carbohydrate (CHO: 116.5 g CHO; 882.5 g total; 0.83 ml fluid), high protein (PRO; 63.5 g PRO; 913 g total; 0.83 ml fluid), and fasted (FAST; 8 hrs fasted). Whole-body, multi-frequency BIS was completed one hour post-meal consumption. Differences in raw bioimpedance values and derived body water estimates between feeding conditions were evaluated using separate repeated measure ANOVAs covaried for average urine specific gravity to account for pre-visit hydration status. RESULTS: There were no significant differences in raw bioimpedance values [R (FAST, CHO, PRO means: 543.0, 545.1, 548.6 Ω; p = 0.418), Xc (67.2, 67.7, 67.7 Ω; p = 0.453), Z (547.2, 549.4, 552.8 Ω; p = 0.416), PhA (7.14, 7.16, 7.12°; p = 0.680)] or derived body water estimates [TBW (40.0, 40.0, 39.8 L; p = 0.289), ECW (16.1, 16.1, 16.1 L; p = 0.131), or ICW (23.9, 23.9, 23.8 L; p = 0.671)] between feeding conditions. CONCLUSION: Acute feeding did not alter raw bioimpedance values taken 1 hr post-meal in healthy young adults. Bioimpedance may not be sensitive to acute changes in nutrition/hydration or consumption of food/drink 1 hr prior to testing was not a long enough equilibration time. Acute food intake may not need to be restricted prior to bioimpedance measurements, which increases feasibility of application in clinical and athletic populations.

Pluronic F127/Doxorubicin microemulsions: Preparation, characterization, and toxicity evaluations

The development of drug delivery systems minimizing the side effects of conventional chemotherapy is one of the major challenges in the field of biomaterials for cancer treatment. This work reports the formulation and characterization of oil-in-water Pluronic F127 microemulsions to enhance the bioavailability of doxorubicin (DOX). The density functional theory (DFT) calculations at the M06-2X level of theory were done to study the interaction details of DOX with ethyl butyrate, sodium caprylate, and one unit of the polymeric chain of surfactant Pluronic F127 in water solution, which are used in the synthesis process. Specifically, the quantum theory of atoms in molecules (QTAIM) analysis was performed to determine the nature of interactions. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies were calculated to show the direction of charge transfer within each complex. Furthermore, the natural bond orbital (NBO) analysis was performed on the studied systems. The size of F127/DOX microemulsion was about 7.0 nm by dynamic light scattering analysis. In vitro toxicity of standard DOX and DOX-loaded microemulsions were assessed against MCF-7 and C152 (malignant) and HUVEC (non-malignant) cell lines. Intracellular lactate dehydrogenase (LDH) leakage was evaluated as an indicator of membrane integrity. In vitro assessments revealed that Pluronic F127/DOX microemulsions caused substantial morphological changes and greater cytotoxic effects than standard DOX. Pluronic F127/DOX microemulsions were injected intraperitoneally at 12 and 24 mg/kg into rats. The free (bulk) DOX group induced severe histopathological changes and significant increases in serum kidney markers and serum liver enzymes. The 24 mg/kg dose of Pluronic F127/DOX microemulsions also induced fatty changes and elevation of serum liver enzymes and creatinine. Overall, this new drug delivery system formulation shows promise for cancer treatment and deserves to be further studied in the future.

Mitochondrial Function in Oxidative and Glycolytic Bovine Skeletal Muscle Postmortem

Meat quality is traditionally associated with anaerobic metabolism due to cessation of the oxygen supply post-mortem. However, mitochondrial (mt) function early postmortem may affect the development of meat quality characteristics, such as adenosine triphosphate levels and pH decline. Therefore, the objective of this study was to evaluate mt function ex vivo during the first 24 h postmortem in muscles with differences in mt content. Samples from longissimus lumborum (LL) and diaphragm (Dia) were taken from steers (n = 6) at 1, 3, and 24 h postmortem and frozen to determine citrate synthase (CS) activity and mt protein expression (immunodetection) or were fresh-preserved for high-resolution respirometry. Integrative oxygen consumption rate (picomoles per second per milligram of tissue) was measured and normalized to CS activity as a proxy for mt content (intrinsic mt function, picomoles per second per unit CS). CS activity (P < 0.001) and mt protein expression (P < 0.001) were greater in Dia, which was reflected in mt respiration. Muscle type affected (P < 0.001) integrative leak respiration and was greater in mt from Dia; oxidative phosphorylation (OXPHOS) was also greater in Dia and influenced by time postmortem (muscle × time: P = 0.01). Intrinsic leak and OXPHOS were affected by muscle and time (muscle × time: P = 0.05 and P = 0.01, respectively), with the most pronounced differences at 24 h postmortem. Stimulation of OXPHOS by cytochrome c as an indicator of outer mt membrane integrity was influenced by muscle and time postmortem (muscle × time: P = 0.03); it was greater in mt from LL. Despite intrinsic differences in respiratory function at 24 h, mt from both muscles were intact and coupled at 1 h postmortem. Reduced content and respiratory function in mt from LL are associated with early fragmentation, which could impact protease activation and subsequently meat quality.

Is phase angle a valuable prognostic tool in cancer patients' survival? A systematic review and meta-analysis of available literature

The phase angle (PA), expressed via bioelectrical impedance, is an indicator of cell membrane health and integrity, hydration, and nutritional status, and may have further application as a prognostic marker in cancer survival. However, the associations between PA and cancer survival are inconsistent and unclear. The present systematic review and meta-analysis investigated the relationship between PA and survival among adult patients diagnosed with cancer. A systematic search of observational studies up to November 2020 was conducted through PubMed, Scopus, and ISI Web of Science. The critical appraisal of the eligible studies was performed using the Newcastle-Ottawa Quality Assessment Scale. Statistical analyses were performed using STATA 11.2 software. A P-value <0.05 was considered statistically significant. A total of 14 studies covering 2625 participants were included in this study. There was a positive and significant correlation between PA and cancer survival (Fisher's Z: 0.30; 95% CI, 0.21-0.40; P<0.001; I2=0.0%). Also, there was a significant prognostic role for PA on patients' survival (HR 0.77; 95% CI, 0.74-0.81; P<0.001; I2=0.0%). In other words, patients with low values of PA were 23% less likely to survive than patients with high values of PA. Given that predicting survival in advanced cancer patients remains a challenge, the findings of this systematic review and meta-analysis suggest that phase angle may be an important prognostic factor of survival in this population.

Propidium iodide enabled live imaging of Pasteuria sp.-Pratylenchus zeae infection studies under fluorescence microscopy.

Live imaging allows observations of cell structures and processes in real time, to monitor dynamic changes within living organisms compared to fixed organisms. Fluorescence microscopy was used to monitor the dynamic infection process of the nematode parasitic bacterium Pasteuria sp. and the sugarcane root-lesion nematode, Pratylenchus zeae. Under fluorescence microscopy, green-autofluorescent globules were observed in live control and Pasteuria sp.-infected nematodes. Only nematodes killed by Pasteuria sp. or heat treated displayed a diffuse pattern of autofluorescence. Propidium iodide (PI), used as a cell membrane integrity indicator, confirmed that the nematode's cuticle acts as an impermeable barrier. PI stained cells/DNA of heat-treated control and Pasteuria sp.-infected P. zeae. PI as a counterstain facilitated the location of Pasteuria endospores on the cuticle surface of P. zeae. No PI staining was observed in sporangia and in endospores within the nematode body. However, PI specifically stained endospores on the cuticle surface and within the cuticle carcass showing, in mature propagules, a ring-like pattern. Live imaging, combined with fluorescence microscopy and fluorescent dyes such as PI, appears useful in live studies on plant nematode interactions with nematophagous bacteria.

Natural feed after weaning improves the reproductive status of Solea senegalensis breeders

The aim of this study was to evaluate the effect of long term natural feeding in the subsequent reproductive status of 4 years old cultured Solea senegalensis, and to determine if the potential changes were structural or feeding dependent. To this aim, two different feeding regimes were used from one year after weaning and during the following 3 years; 1) a commercial dry food diet and 2) a natural feeding regime. After this period, the proportion of fluent males and the evolution of maturity stages of females over a breeding season were studied. A complete sperm quality analysis assessment was carried out, including individual volumes, motility, density and curvilinear, rectilinear and mean velocities of spermatozoa. Moreover, viability and apoptosis indexes were analyzed as indicator of molecular sperm membrane integrity. Additionally, a morphological characterization of the testes during the spawning season was conducted. Finally, both groups were fed with the same commercial pellets during one year to evaluate the effect of the diet of previous years on sperm quality. The results of this study showed how feeding can improve not only sperm quality and quantity, but also the proportion of fluent males and females in advanced maturity stages. All the sperm quality parameters resulted significantly higher in the group fed with a natural diet. Moreover, the number of apoptotic cells was significantly higher in the group fed with a commercial diet. According to the morphological features of the testes, the animals fed with a natural diet presented more basal position, less protuberances and irregular edges when compared with the animals fed with commercial diet. Interestingly, the progression of the spermatogenesis determined by the proportion of germ cells and the production of spermatozoa determined by the wider of the ducts system was also significantly larger in the natural diet group.After the standardization of the diets, mean volume per male and production of total motile cells were significantly higher in the group that was previously fed a natural diet, confirming structural improvements.

Hormetic doses of UV‐C light decrease the susceptibility of tomato plants to Botrytis cinerea infection

AbstractPreharvest hormetic doses of UV‐C radiation can decrease the susceptibility of tomato leaves to Botrytis cinerea L. infection. UV‐C light treatments have been shown to be very effective for reducing disease development in several species, including tomato (Solanum lycopersicum L.). Treating cultivated tomato plants with UV‐C light is of interest not only because of the disinfecting effects of UV‐C light but also because of its ability to stimulate plant defences (SDP) against diseases, provided that the applied doses are high enough to be effective while low enough to prevent deleterious effects. In the present study, the effects of UV‐C light on plants were evaluated by biochemical analyses, including analyses of the activities of antioxidant enzymes and phenylalanine lyase (PAL); the concentration of malondialdehyde (MDA), an indicator of membrane integrity; and chlorophyll fluorescence parameters, such as the maximum quantum efficiency of photosystem II (FV/FM) and the Strasser performance index (PI). In this work, treatments with single doses of 0.85 kJ/m2 of UV‐C light were found to significantly increase plant defences against B. cinerea, reducing the affected leaf area by 51% compared to the affected area of control plants. This decrease in susceptibility was associated with increased PAL activity and the amount of bound phenolics compared to levels in control plants (not treated with UV‐C).

High abdominal adiposity and low phase angle in overweight renal transplant recipients.

Obesity is associated with increased risk of cardiovascular disease (CVD). Body mass index (BMI) is the most used parameter for obesity screening. However, the evaluation of CVD risk in overweight individuals should include the assessment of body fat distribution and body composition. Renal transplant recipients (RTR) have a high CVD risk and frequently present weight gain and loss of lean mass. The aim of this study was to evaluate body fat distribution and body composition in overweight RTR. This cross-sectional study was conducted with 86 RTR and 86 hypertensive individuals (comparison group, CG) presenting BMI 25-35Kg/m2 and 45-70years. Anthropometric evaluation included BMI, waist circumference, waist-to-height ratio, and a body shape index. Body composition was evaluated with bioelectrical impedance analysis (BIA). Glomerular filtration rate was estimated (eGFR) by CKD-EPI equation. RTR group (RTRG) and CG presented similar age and BMI. RTRG when compared to CG presented lower percentage of women and eGFR; higher central adiposity; and lower values of reactance, intracellular water, body cell mass and phase angle, more consistently observed in women. This study suggests that overweight RTR present higher abdominal adiposity and impairment in BIA parameters that are sensitive indicators of impaired membrane integrity, water distribution, and body cell mass.

Understanding the effect of Pulsed Electric Fields on multilayered solid plant foods: Bunching onions (Allium fistulosum) as a model system

While it is well known that the nature of the applied electric field and the heterogeneity of the tissue can influence the impact of PEF treatment on the plant tissues found in plant-based foods, few studies have investigated the influence of PEF on plant structures that are made up of multiple structurally similar organs. The aim of this study was to understand the effect of pulsed electric fields (PEF), at different electric field strengths (0, 0.3, 0.7 and 1.2 kV/cm) and specific energy (7, 21 and 52 kJ/kg), on a multilayered plant material, with bunching onion bulb tissues being used as a model system. The present study found that carbohydrates leakage was an appropriate index to assess PEF induced damage and that plasmolysis of epidermal cells was a good indicator of plasma membrane integrity after PEF. In addition, electric field strength had a greater impact on the cell integrity than specific energy applied. While other studies have shown that different cell types have different sensitivities to PEF, using plasmolysis as an indicator of cell damage, this study clearly showed that the same PEF treatment conditions had a greater effect on the epidermal cells of the outer scales compared to the inner scales. Hence, while different plant cell types vary in their sensitivities to PEF the spatial location of the same cell type within a complex plant material made up of multiple similar organs, i.e. an onion bulb, can also influence how cells respond to the PEF treatment. Despite PEF induced disruption at the cellular level being detected by carbohydrate leakage, the epidermal cell plasmolysis test and by cryo-scanning electromicroscopy (cryo-SEM), no gross structural changes at the organ level were observed using cryo-SEM or fluorescence microscopy. This study also reports for the first time that PEF treatment can enhance fructan leakage from onion bulbs, which means that PEF treatments have the potential to manipulate the fructan contents of some plant-based foods.

HJH-1, a Broad-Spectrum Antimicrobial Activity and Low Cytotoxicity Antimicrobial Peptide.

With the overuse of antibiotics, multidrug-resistant bacteria pose a significant threat to human health. Antimicrobial peptides (AMPs) are a promising alternative to conventional antibiotics. This study examines the antimicrobial and membrane activity of HJH-1, a cationic peptide derived from the hemoglobin α-subunit of bovine erythrocytes P3. HJH-1 shows potent antimicrobial activity against different bacterial species associated with infection and causes weaker hemolysis of erythrocytes, at least five times the minimum inhibitory concentration (MIC). HJH-1 has good stability to tolerance temperature, pH value, and ionic strength. The anionic membrane potential probe bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)] and propidium iodide are used as indicators of membrane integrity. In the presence of HJH-1 (1× MIC), Escherichia coli membranes rapidly depolarise, whereas red blood cells show gradual hyperpolarisation. Scanning electron microscopy and transmission electron micrographs show that HJH-1 (1× MIC) damaged the membranes of Escherichia coli, Staphylococcus aureus, and Candida albicans. In conclusion, HJH-1 damages the integrity of the bacterial membrane, preventing the growth of bacteria. HJH-1 has broad-spectrum antibacterial activity, and these activities are performed by changing the normal cell transmembrane potential and disrupting the integrity of the bacterial membrane.

Association of equine sperm population parameters with outcome of intracytoplasmic sperm injections

Limited clinical information is available regarding sperm population parameters that are important for use with equine intracytoplasmic sperm injection (ICSI). Therefore, the appropriateness of a sample of sperm is typically not known before ICSI. The aim of our study was to determine which sperm population characteristics were predictive of ICSI outcome. Frozen-thawed sperm samples (n = 114) from 37 stallions in a clinical program were analyzed after ICSI for percentages of normal morphology (MORPH+), live as assessed by eosin/nigrosin stain (LIVE+), membrane intact as assessed by hypoosmotic swelling test (HOS+), and DNA fragmentation determined by sperm chromatin dispersion (DNA–). ICSI was performed on 147 oocytes, and cleavage (≥2 cells), embryo development (morula or blastocyst), and pregnancy status after embryo transfer were determined. Among the examined sperm parameters, LIVE + correlated positively with MORPH+ and HOS+, and MORPH + negatively with DNA–; no other significant correlations were observed. When used for ICSI, sperm population percentages for MORPH+ and DNA– were not predictive of ICSI outcome, including cleavage, embryo development, and establishment of a pregnancy. Sperm population percentages significantly affecting ICSI outcomes were LIVE+ and HOS + for oocyte cleavage, LIVE + for embryo development, and HOS + for establishment of a pregnancy. The probability of a pregnancy was significantly higher for sperm populations having HOS+ ≥40% than populations having HOS+ ≤20%. The mean age of the donor mare per sperm-injected oocyte did not differ for oocyte cleavage, embryo production, or establishment of pregnancy. In our study, the probability of sperm-injected oocytes to develop into an embryo (morula or blastocyst) improved when sperm were selected from a population with higher indicators of membrane integrity (LIVE+ and HOS+).

Ionomycin-Induced Changes in Membrane Potential Alter Electroporation Outcomes in HL-60 Cells

Previous studies have shown greater fluorophore uptake during electroporation on the anode-facing side of the cell than on the cathode-facing side. Based on these observations, we hypothesized that hyperpolarizing a cell before electroporation would decrease the requisite pulsed electric field intensity for electroporation outcomes, thereby yielding a higher probability of reversible electroporation at lower electric field strengths and a higher probability of irreversible electroporation (IRE) at higher electric field strengths. In this study, we tested this hypothesis by hyperpolarizing HL-60 cells using ionomycin before electroporation. These cells were then electroporated in a solution containing propidium iodide, a membrane integrity indicator. After 20 min, we added trypan blue to identify IRE cells. Our results showed that hyperpolarizing cells before electroporation alters the pulsed electric field intensity thresholds for reversible electroporation and IRE, allowing for greater control and selectivity of electroporation outcomes.

Abstract O-36: FACTORS ASSOCIATED WITH PHASE ANGLE IN CRITICALLY ILL CHILDREN

Aims & Objectives: Phase angle (PA), evaluated by bioelectrical impedance analysis, can be used as an indicator of cell membrane integrity and as a prognostic parameter in clinical situations. PA is determined directly from resistance and reactance and reflects body cell mass, thus may be a useful parameter for nutritional risk screening. The aim of this study was to evaluate the factors associated with PA in critically ill children. Methods Prospective study conducted in a Pediatric Intensive Care Unit (PICU) with children aged between 1 month and 15 years. Demographic and clinical data were assessed at admission. Bioelectrical impedance analysis, laboratorial and anthropometric measures were performed within 72 hours of admission. PICU and hospital length of stay (LOS), nosocomial infection and overall mortality were assessed. Man-Whitney, Fisher’s Test, Spearman correlation, linear and logistic regression were applied. P-value <0.05 was considered significant. Results A total of 76 patients were included, 54% male, median age of 1.9 (Interquartile range (IQR) 0.33; 9.07) years and median Pediatric Index of Mortality (PIM-2) of 2.35% (IQR 0.95; 6.8) (Table 1). Lower PA was associated with higher C-reactive protein (CRP) (mg/L) (p=0.048) and with higher CRP/albumin ratio (p=0.038), even after adjustment for sex, age and PIM-2 (p=0.02 and p=0.014, respectively (Table 2). No association between PA and anthropometry (Table 2) or clinical outcomes (data not shown) were observed.Conclusions PA was associated with inflammatory markers in critically ill children. More studies are necessary to evaluate the usefulness of PA in this population.

The Prognostic Role of Phase Angle in Advanced Cancer Patients: A Systematic Review.

Phase angle (PA) is a ratio between the reactance and resistance obtained by bioelectric impedance analysis and has been interpreted as a cell membrane integrity indicator and a predictor of total body cell mass. A low PA may suggest deterioration of the cell membrane, which in advanced cancer patients may result in a reduced overall survival (OS). This systematic review sought to investigate the current evidence regarding whether there is an association between PA and OS in patients with advanced cancer (ie, metastatic disease). The search was conducted on electronic databases in August 2017. A total of 34 articles were identified in the initial literature search. Nine studies reporting on 1496 patients were deemed eligible according to our inclusion criteria. PA data were analyzed as continuous variables or according to different cutoffs, under a frequency of 50 Khz. Low PA was associated with worse nutrition status evaluated by body mass index, serum albumin level, transferrin, and fat-free mass. The median OS of the included papers varied from 25.5-330 days, and all studies analyzed showed a significant association between PA and OS, in that patients with low PA had worse OS. Future studies are necessary to justify the use of PA in therapeutic decisions for this population and to evaluate whether nutrition status can influence the association between PA and survival.

Effect of long-term storage on physiology of cut roses

Long-term shipment of flowers in reefer containers as a replacement of airfreight is the method of choice with respect to saving on transport costs and decreasing the carbon footprint. Long term storage, in general, also facilitates the required delivery of large volumes on peak days such as Mother's day or Valentine's day. Optimal storage conditions have been developed over the years for a variety of flowers and cultivars with varying degrees of success. In roses, the long storage at low temperature may induce a number of disorders that greatly shorten the remaining vase life. The symptoms observed during the vase life of long term stored roses are mainly on performance of the flower head (botrytis, wilting, bent neck, impaired opening) and occasionally also on the performance of the leaves (blackening, desiccation, abscission). The physiological basis of the flower performance problems was investigated in different rose cultivars. Long term storage did not affect the xylem hydraulic conductivity and did not alter the petal sugar status or petal electrolyte leakage (indicator of membrane integrity). Storage was found to affect the functionality of stomata leading to less adequate stomata closing in response to mild water stress.

Performance evaluation of phase angle and handgrip strength in patients undergoing cardiac surgery: Prospective cohort study

Background and aimsThe phase angle (PA), derived from bioelectrical impedance analysis (BIA), has been interpreted as a cell membrane integrity indicator, while handgrip strength (HGS) has been used as a prognostic indicator in certain clinical situations, such as in cardiac, oncologic patients with renal disease, hemodialysis patients, HIV-positive patients, and liver disease patients. In addition to prognostic scores, body changes due to surgical procedures indicate the importance of measuring muscle function and cell integrity. This study aimed to evaluate the behaviour of PA and HGS in patients undergoing cardiac surgery and associate these factors with clinical outcomes and prognosis. MethodsThis was a prospective cohort study of 50 consecutively recruited patients (aged ≥18 years) undergoing cardiac surgery. Measures PA and HGS were at three set points: preoperative, at hospital discharge and three months postoperative. The following data were collected: time of cardiopulmonary bypass (CPB), ischemia, mechanical ventilation (MV), Intensive Care Unit (ICU) length of stay (LOS) and hospital LOS after surgery; the EuroSCORE was also calculated. ResultsA decrease in PA was observed between the preoperative and the two postoperative stages (p<0.001). There was a reduction in HGS between the preoperative and hospital discharge assessments (p<0.001) and a recovery three months postoperative (p<0.001). The MV and EuroSCORE were inversely associated with PA and HGS in all three assessments. The PA was correlated with EuroSCORE in the first assessment (p=0.007) and in the second and third assessments (p<0.001), as well as with MV in all three assessments (p<0.001). The HGS was correlated with EuroSCORE and MV in the first and second assessments (p<0.001) and in the third assessment (p=0.010 and p=0.018, respectively). ConclusionPA and HGS appear to be related to MV time, ICU LOS and hospital LOS after surgery in patients undergoing cardiac surgery.

Resuscitation and growth kinetics of sub-lethally injured Listeria monocytogenes strains following fluorescence activated cell sorting (FACS)

This study investigated the effect of acid (pH4.2), osmotic (10% NaCl) and heat (55°C for 30min) stress induced injury on Listeria monocytogenes strains ATCC19115, 69, 159/10 and 243 using differential plating and flow cytometry coupled with membrane integrity indicators, thiazole orange (TO) and propidium iodide (PI) staining. Growth kinetics of injured cells sorted by fluorescence activated cell sorting (FACS) were studied at 4, 25 and 37°C. The percentage of cell injury detectable by both flow cytometry and differential plating varied significantly among strains and stress treatments (p<0.0001). Based on flow cytometry and TO/PI staining, acid stress caused the highest level of injury followed by heat and osmotic stress. Following cell sorting, acid and osmotic stress injured cells were capable of resuscitation and re-growth while heat injured cells (except for strain 69) were incapable of re-growth despite having a high level of membrane intact cells. The lag phase duration (λ) of sorted stress injured cells resuscitated in brain heart infusion (BHI) broth was significantly influenced by strain variations (p<0.0001), stress treatments (p=0.007) and temperature of resuscitation (p≤0.001). Following repair, the maximum specific growth rate (μmax) of resuscitated cells was not different from untreated control cells regardless of strain differences and stress treatments. Only temperature had a significant effect (p<0.0001) on growth rate. Sorted cells were also capable of growth at 4°C, with the time to detectable growth (≥1.40Log10CFUml−1) ranging from 3 to 15days. Overall, re-growth potential of sorted cells showed that while membrane integrity was a good indicator of cell injury and viability loss for acid and osmotic stress, it was not a sufficient indicator of heat stress injury. Once injured cells repair the cellular damage, their growth rate is not different from non-injured cells regardless of form of stress and strain differences. Thus highlighting the potential food safety risks of stress injured L. monocytogenes cells.

Pre-harvest hormetic doses of UV-C radiation can decrease susceptibility of lettuce leaves (Lactuca sativa L.) to Botrytis cinerea L.

Post-harvest applications of UV-C radiation have proven very efficient in reducing the development of post-harvest diseases in many species including lettuce (Lactuca sativa L.). Several studies suggest that UV-C radiation is effective not only because of its disinfecting effect but also because it may stimulate plant defenses. Pre-harvest treatment with UV-C radiation may thus offer an interesting potential for lettuce protection, provided that application doses are effective while excluding any harmful effects on the plants. Here we provide evidence that 0.85kJm−2 and 1.70kJm−2 represent doses of UV-C radiation that are not deleterious for lettuce plants. We used several criteria to evaluated the effect of UV-C radiation on the plant, including histological observations; the concentration of malondialdehyde, an indicator of membrane integrity, as well as parameters derived from measurements of chlorophyll fluorescence, such as maximal efficiency of photosystem II (Fv/Fm) and the Performance Index of Strasser. We observed that a single dose of 0.85kJm−2 slightly increased plant resistance to grey mould (Botrytis cinerea L.) while a single dose of 1.70kJm−2 had the opposite effect. When a 0.85kJm−2 dose was applied 4 times, at two-day intervals, there was an increase in the total phenol content of leaves, and in PAL, CAT, and MDAHR activities. Leaves inoculated 2 days after the latter UV-C treatment showed significantly decreased sensitivity (−30%) when compared to the control.