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

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

Non-Gaussian power grid frequency fluctuations characterized by Levy-stable laws and superstatistics

Multiple types of fluctuations impact the collective dynamics of power grids and thus challenge their robust operation. Fluctuations result from processes as different as dynamically changing demands, energy trading and an increasing share of renewable power feed-in. Here we analyse principles underlying the dynamics and statistics of power grid frequency fluctuations. Considering frequency time series for a range of power grids, including grids in North America, Japan and Europe, we find a strong deviation from Gaussianity best described as Lévy-stable and q-Gaussian distributions. We present a coarse framework to analytically characterize the impact of arbitrary noise distributions, as well as a superstatistical approach that systematically interprets heavy tails and skewed distributions. We identify energy trading as a substantial contribution to today’s frequency fluctuations and effective damping of the grid as a controlling factor enabling reduction of fluctuation risks, with enhanced effects for small power grids

Treatment of hemangiomas in children using a Nd:YAG laser in conjunction with ice cooling of the epidermis: techniques and results

BACKGROUND: Hemangiomas are the most common type of congenital anomaly in childhood. Although many resolve spontaneously, intervention is required when their growth could damage vital adjacent structures. Various therapeutic approaches to childhood hemangiomas with different types of laser have been described previously. The objective of this study was to determine whether the cooling of the epidermis during irradiation of hemangiomas with a Nd:YAG laser prevents thermal damage and decreases the number of sessions required to treat these lesions. METHODS: Between 1993 and 2001, 110 patients aged 3 months to 4 years, with cutaneous hemangiomas were treated with a Nd:YAG laser. The lesion was cooled with ice prior to, during, and after the irradiation. During each session the laser beam passed through the pieces of ice. The laser power was between 35–45 W with a pulse length of 2–10 seconds. RESULTS: After 6 months of follow-up, from the first session of laser treatment, total resolution was obtained in 72 (65.5%) patients. A second or third session followed in 30 out of 38 patients in which, the initial results were good, moderate, or poor. The parents of the remaining eight children refused this second session and these patients excluded from the study Complications were seen in nine (8.8%) patients. One patient had postoperative bleeding which stopped spontaneously, while atrophic scars occurred in six (5.8%) patients, and hypertrophic scars in two (1.9%) patients. CONCLUSIONS: Nd:YAG laser irradiation in conjunction with ice protection of the epidermis produces good cosmetic results for the treatment of cutaneous hemangiomas in children, and decreases the number of sessions for treatment of these lesions