Effects of plasma membrane cholesterol level and cytoskeleton F-actin on cell protrusion mechanics.

Protrusions are deformations that form at the surface of living cells during biological activities such as cell migration. Using combined optical tweezers and fluorescent microscopy, we quantified the mechanical properties of protrusions in adherent human embryonic kidney cells in response to application of an external force at the cell surface. The mechanical properties of protrusions were analyzed by obtaining the associated force-length plots during protrusion formation, and force relaxation at constant length. Protrusion mechanics were interpretable by a standard linear solid (Kelvin) model, consisting of two stiffness parameters, k0 and k1 (with k0>k1), and a viscous coefficient. While both stiffness parameters contribute to the time-dependant mechanical behavior of the protrusions, k0 and k1 in particular dominated the early and late stages of the protrusion formation and elongation process, respectively. Lowering the membrane cholesterol content by 25% increased the k0 stiffness by 74%, and shortened the protrusion length by almost half. Enhancement of membrane cholesterol content by nearly two-fold increased the protrusion length by 30%, and decreased the k0 stiffness by nearly two-and-half-fold as compared with control cells. Cytoskeleton integrity was found to make a major contribution to protrusion mechanics as evidenced by the effects of F-actin disruption on the resulting mechanical parameters. Viscoelastic behavior of protrusions was further characterized by hysteresis and force relaxation after formation. The results of this study elucidate the coordination of plasma membrane composition and cytoskeleton during protrusion formation

Comparative study on the effectiveness acetaminophen and diclofenac on pretreatment in the relief of pain after out-patient surgery

The aim of this study is to evaluate and quantify the pain relief after minor surgery when certain analgesics are used before surgery. Double blind study was conducted on 300 outpatient surgery patients who were allocated into two groups. Before surgery, 100 mg of acetaminophen was given to one group and 75 mg of diclofenac to the other one. The pain level after surgery was measured and recorded in both groups by a ruler 10 cm using the Visual Analog Scale (VAS) method at intervals of 30 min, 1, 2 and 4 h after surgery. Also for the patients with VAS more than 7, it was recommended to administer IM 50-100 mg teramadole ampoule. Mean VAS in acetaminophen group was 5.28±1.17, 5.17 ±1.04, 4.47±1.05±, 3.97±1.09 while, in diclofenac group was 5.09±1.10, 5.10±1.024.27±1.05 and 3/73±1.07 at 0.5, 1, 2 and 4 h after surgery, respectively. In fact there was no significant difference in pain level after surgery between acetaminophen and diclofenac groups (p>0.05). Moreover, there was no significant difference in the effectiveness of pain relief induced by administering tramadol calmative ampoule along with acetaminophen and diclofenac groups (p>0.05). Acetaminophen results in as effective pain relief as diclofenac with or without tramadol calmative. Due to minimal side effects of acetaminophen when compared to other analgesics, like diclofenac, it is recommended to use acetaminophen for safe and efficient pain relief after outpatients surgeries

Assessing Validity and Bias of Within- Person Variability in Affect and Personality

Within-person variability in affect (e.g., Neuroticism) and personality have been linked to well-being. These are measured either by asking people to report how variable they are or to give multiple reports on the construct and calculating a within-person standard deviation adjusted for confounding by the person-level mean. The two measures are weakly correlated with one another and the links of variability with well-being depend on which measure researchers use. Recent research suggests that people’s repeated ratings may be biased by response styles. In a 7-day study (N = 399) with up to five measurements per day, we confirmed that the measures of variability lacked sufficient convergent validity to be used interchangeably. We found only 1 significant correlation (of 10) between variability in repeated ratings of affect or personality and variability in repeated ratings of a theoretically unrelated construct (i.e., features of images). There was very little evidence supporting the response styles hypothesis

Tissue-derived proinflammatory effect of adenosine A2B receptor in lung ischemia–reperfusion injury

ObjectiveIschemia–reperfusion injury after lung transplantation remains a major source of morbidity and mortality. Adenosine receptors have been implicated in both pro- and anti-inflammatory roles in ischemia–reperfusion injury. This study tests the hypothesis that the adenosine A2B receptor exacerbates the proinflammatory response to lung ischemia–reperfusion injury.MethodsAn in vivo left lung hilar clamp model of ischemia–reperfusion was used in wild-type C57BL6 and adenosine A2B receptor knockout mice, and in chimeras created by bone marrow transplantation between wild-type and adenosine A2B receptor knockout mice. Mice underwent sham surgery or lung ischemia–reperfusion (1 hour ischemia and 2 hours reperfusion). At the end of reperfusion, lung function was assessed using an isolated buffer-perfused lung system. Lung inflammation was assessed by measuring proinflammatory cytokine levels in bronchoalveolar lavage fluid, and neutrophil infiltration was assessed via myeloperoxidase levels in lung tissue.ResultsCompared with wild-type mice, lungs of adenosine A2B receptor knockout mice were significantly protected after ischemia–reperfusion, as evidenced by significantly reduced pulmonary artery pressure, increased lung compliance, decreased myeloperoxidase, and reduced proinflammatory cytokine levels (tumor necrosis factor-α; interleukin-6; keratinocyte chemoattractant; regulated on activation, normal T-cell expressed and secreted; and monocyte chemotactic protein-1). Adenosine A2B receptor knockout→adenosine A2B receptor knockout (donor→recipient) and wild-type→ adenosine A2B receptor knockout, but not adenosine A2B receptor knockout→wild-type, chimeras showed significantly improved lung function after ischemia–reperfusion.ConclusionsThese results suggest that the adenosine A2B receptor plays an important role in mediating lung inflammation after ischemia–reperfusion by stimulating cytokine production and neutrophil chemotaxis. The proinflammatory effects of adenosine A2B receptor seem to be derived by adenosine A2B receptor activation primarily on resident pulmonary cells and not bone marrow-derived cells. Adenosine A2B receptor may provide a therapeutic target for prevention of ischemia–reperfusion-related graft dysfunction in lung transplant recipients

Detection of vim- and ipm-type metallo-beta-lactamases in Pseudomonas aeruginosa clinical isolates

BACKGROUND: Pseudomonas aeruginosa is the most important bacterium isolated from burn wounds, and its resistance to imipenem due to metallo-beta-lactamases is increasing. This study was designed to detect vim1, vim2, ipm1 and ipm2 metallo-beta-lactamases genes between Pseudomonas aeruginosa isolates isolated from Shahid Motahari Burns Hospital, Iran. METHODS: To that end, we isolated 483 nonduplicate consecutive isolates of P. aeruginosa from burn infections; and after biochemical confirmation, we examined the imipenem susceptibility via the Kirby-Bauer method. All the imipenem-resistant and imipenem-intermediate isolates were screened for vim1, vim2, ipm1 and ipm2 genes through the PCR method. RESULTS: From the 483 isolates, 272 (56) and 63 (13) isolates had resistant and intermediate zones in their imipenem antibiogram pattern, respectively. Fifty-four (16.1), 7 (2.1), 22 (6.6), and 11 (3.3) of the resistant and intermediate isolates had vim1, vim2, ipm1 and ipm2 genes in their PCR results, respectively. CONCLUSION: MBL-mediated imipenem resistance in P. aeruginosa is a cause for concern in the treatment of infective burn patients. The rate of imipenem resistance due to MBL was increased dramatically and newer versions of MBL families were detected for the first time. These results suggest that an effective method should be provided to fight MBL production in clinical isolates

Quantifying the impact of Covid-19 on the energy consumption in the low-income housing in Greater London

Covid-19 has caused great challenges to the energy sector, particularly in residential buildings with low-income households. This study investigates the impact of the confinement measures due to the Covid-19 outbreak on the energy demand of seven residential archetype buildings in Greater London. Three levels of confinement for occupant schedules are proposed and compared with the base case before Covid-19. The archetypes, their boundary conditions, and input parameters are set up according to statistics from English Housing Survey (EHS) sample data for low-income housing. The base case scenario (normal life without confinement measures) is validated against the measured data energy consumption from the National Energy Efficiency Data-Framework (NEED) statistics. The results show that electricity consumption is significantly lower than that for heating and hot water for all the archetypes. By comparing the base case scenario with the full Covid-19 lockdown scenario, the results indicate that heating and hot water consumption (kWh) for all the residential archetypes increases, on average, by 10%, and total electricity demand (kWh) increases by 13%. The study highlights the importance of introducing detailed occupancy profiles in multi-zone building energy simulation models during a pandemic that leads to a greater shift towards home working, which may increase the risk of fuel poverty in low-income housing.Peer reviewe