Transversus abdominis-plane block versus local anesthetic wound infiltration in lower abdominal surgery: a systematic review and meta-analysis of randomized controlled trials

Background: Postoperative pain management is of great importance in perioperative anesthetic care. Transversus abdominis plane (TAP) block has been described as an effective technique to reduce postoperative pain and morphine consumption after open lower abdominal operations. Meanwhile, local anesthetic infiltration (LAI) is also commonly used as a traditional method. However, the effectiveness of these two methods has not been compared before. Methods: A meta-analysis of all relevant randomized controlled trials (RCTs) was conducted to compare the efficacy of single shot TAP block with that of single shot LAI for postoperative analgesia in adults. Major medical databases and trial registries were searched for published and unpublished RCTs. The endpoints include postoperative visual analog scale (VAS) pain score, morphine requirement, and rate of postoperative nausea and vomiting (PONV). For continuous data, weighted mean differences (WMDs) were formulated; for dichotomous data, risk ratios (RR) were calculated. Results were derived using a random-/fixed-effects model with 95% confidence interval (CI). Results: Four RCTs, encompassing 96 TAP-block and 100 LAI patients, were included in the final analysis. Patients in the TAP-block group had lower VAS pain scores 24 hours postoperatively compared with the LAI group, both at rest (WMD [95% CI] = -0.67 [p < 0.01] and with movement (WMD = -0.89, p < 0.01). There were no significant between-group differences in 24-hour postoperative morphine requirements, the rates if PONV or VAS pain scores at 2 and 4 h postoperatively. Conclusion: TAP block and LAI provide comparable short-term postoperative analgesia, but TAP block has better long-lasting effect. Electronic supplementary material The online version of this article (doi:10.1186/1471-2253-14-121) contains supplementary material, which is available to authorized users

Diffusion and Perfusion: The Keys to Fat Grafting

Background: Fat grafting is now widely used in plastic surgery. Long-term graft retention can be unpredictable. Fat grafts must obtain oxygen via diffusion until neovascularization occurs, so oxygen delivery may be the overarching variable in graft retention. Methods: We studied the peer-reviewed literature to determine which aspects of a fat graft and the microenvironment surrounding a fat graft affect oxygen delivery and created 3 models relating distinct variables to oxygen delivery and graft retention. Results: Our models confirm that thin microribbons of fat maximize oxygen transport when injected into a large, compliant, well-vascularized recipient site. The “Microribbon Model” predicts that, in a typical human, fat injections larger than 0.16 cm in radius will have a region of central necrosis. Our “Fluid Accommodation Model” predicts that once grafted tissues approach a critical interstitial fluid pressure of 9 mm Hg, any additional fluid will drastically increase interstitial fluid pressure and reduce capillary perfusion and oxygen delivery. Our “External Volume Expansion Effect Model” predicts the effect of vascular changes induced by preoperative external volume expansion that allow for greater volumes of fat to be successfully grafted. Conclusions: These models confirm that initial fat grafting survival is limited by oxygen diffusion. Preoperative expansion increases oxygen diffusion capacity allowing for additional graft retention. These models provide a scientific framework for testing the current fat grafting theories

Marjolin’s ulcer: a preventable malignancy arising from scars

Background: Marjolin’s ulcer (MU) is a rare malignancy arising from various forms of scars. This potentially fatal complication typically occurs after a certain latency period. This article attempts to reveal the importance of the latency period in the prevention and early treatment of the malignancy. Methods: A retrospective review of 17 MU patients who underwent surgical procedures between June of 2005 and December 2011 was conducted. Etiology of injuries, latency period, repeated ulceration, and outcomes were recorded. This observational report reveals characteristics of patients who develop MU. Results: An incidence of 0.7% of MU was found amongst patients complaining of existing scars in our study; burns and trauma were the most common etiology of MU. The mean latency period was 29 years (SD = 19) and the mean post-ulceration period was 7 years (SD = 9). Statistical analysis revealed a negative correlation between the age of patients at injury and the length of latency period (r = −0.8, P <0.01), as well as the lengths of pre-ulceration and post-ulceration periods (r = −0.7, P <0.01). Conclusions: Patients experience different lengths of pre- and post-ulceration periods during the latency period. Younger patients tend to have a longer latency period. Skin breakdown on chronic scars and chronic unhealed ulcers are two main sources of MU. MU may be preventable with a close surveillance of the ulcer during the latency period

Perfusion Changes by Hyperspectral Imaging in a Burn Model

BACKGROUND: Early excision and skin grafting of full-thickness and deep-dermal burns is therapeutically advantageous. However, while full-thickness burns are clinically evident, differentiating between superficial versus deep partial-thickness burns presents a diagnostic challenge, with only 50-75% accuracy. Superficial-dermal burns heal, while deep-dermal burns often require excision and skin grafting. Decision of surgical treatment is often delayed until burn depth is definitively identified. This study’s aim is to establish a thermal burn model in mice in order to assess the ability of Hyperspectral Imaging (HSI) in differentiating burn depth. METHODS: Burns of graded severity were generated on the dorsum of seventy-six hairless mice with a brass rod heated to 50, 60, 70, 80, or 90°C. Perfusion and oxygenation parameters of the injured skin were measured with HSI, a non-invasive method of wide-field, diffuse reflectance spectroscopy at 2 minutes, 1 hour, 24 hours, 48 hours, and 72 hours after wounding. Burn depth was measured histologically (n=44) at 72 hours post injury using Masson’s trichrome staining. RESULTS: Three discrete levels of burn depth were verified histologically, as follows in order of increasing depth: intermediate-dermal, deep-dermal, and full-thickness injury. At 24 hours post injury, total hemoglobin increased by 67% and 18% in intermediate and deep dermal burns, respectively. In contrast, total hemoglobin decreased by 64% in full-thickness burns. Differences in deoxygenated hemoglobin, total hemoglobin, and oxygen saturation for all group comparisons were statistically significant (p CONCLUSION: HSI was able to differentiate among three discrete levels of burn injury. This is likely due to its correlation with skin perfusion: superficial burn injury causes an inflammatory response and increased perfusion to the burn site, while deeper burns destroy the dermal microvasculature and a decrease in perfusion follows. This study supports further investigation in the use of HSI in early burn depth assessment

Adipose Tissue Therapeutics for Scar Rehabilitation after Thermal Injury

Background: Burn injuries are common and in the long term can lead to hypertrophic or keloid scars, pain and pruritus, limited mobility across joints, and disfigurement. Numerous reports suggest adipose derived tissues, including adipose derived stem cells (ADSCs) and processed lipoaspirate, can improve acutely healing wounds from a variety of etiologies including excisional, thermal, and radiation injuries by both secretion of growth factors and direct differentiation. There are many options for scar treatment, including laser therapy, silicone sheets, steroid injection, and even skin grafting however these techniques either lack optimal efficacy or involve significant cost and morbidity. Clinical case series suggest a beneficial effect of adipose tissues in improving scarred tissues, however this phenomenon has not been extensively studied in animal models especially in a thermal scar model. Objectives: (1) Determine if adipose tissue can accelerate and improve scar remodeling subacutely after acute wound healing has occurred. (2) Determine if the effect is related to adipose derived stem cells or other components of lipoaspirate. Methods: 50 CD1 nu/nu athymic mice received a standardized 70°C 10 second burn with a brass rod to the dorsal skin. Digital photographs and hyperspectral images were taken immediately following injury and serially over the study’s entirety. Burned skin reliably progressed through normal stages of wound healing to a scarred and granulating state. At six weeks post-burn animals received subcutaneous injection immediately beneath the scar with fresh human lipoaspirate (n=10), high dose hADSCs in matrigel (n=10), low dose hADSCs in matrigel (n=10), matrigel control (n=10), or were not injected (n=10). At 4 weeks post-injection (10 weeks post-burn) animals were sacrificed and tissue samples were harvested for histological molecular analysis. Results: Oxygenation and perfusion profiles from hyperspectral imaging and scar wound area correlated between groups suggesting methodological consistency of burns prior to any intervention. Oxygenated hemoglobin at 10 weeks in scars treated with lipoaspirate increased significantly more compared to 6-week pre-treatment baseline than all other groups (1.57x vs. 0.85x, p Conclusion: A consistent model of burn injury and scar maturation is described. Preliminary HSI and scar area data suggest scar improvement in lipoaspirate treated scars compared to ADSCs and controls

Translational Model for External Volume Expansion in Irradiated Skin

Introduction: External Volume Expansion (EVE) treatment has gained popularity in breast reconstruction, enriching recipient sites for fat grafting. For patients receiving radiotherapy (XRT), results of EVE use vary, partly because the effects of EVE on irradiated tissue are not well understood. Based on our previous work with EVE and XRT, we developed a new translational model to investigate the effects of EVE in the setting of chronic radiation skin injury. Methods: Twenty-Eight SKH1-E mice received 50Gy of beta-radiation to each flank. Animals were monitored until chronic radiation fibrosis developed (8 weeks). EVE was then applied to one side for 6hrs on 5 consecutive days. The opposite side served as control. Hyperspectral Imaging (HSI) was used to assess perfusion changes before and after EVE. Mice were sacrificed at 5 days (n=14) and 15 days (n=14) after last application for histological analysis. Tissue samples were stained for vascularity (CD31) and collagen composition (Picro-Sirius red). Results: All animals developed skin fibrosis 8 weeks post-radiation, and changes in perfusion verified skin damage. EVE application induced edema on treated sides. Five days post-application, both sides were hypo-perfused as seen by HSI; with the EVE side 13% more ischemic than the untreated side (p\u3c0.001). Perfusion returned to control side levels by day 15. Blood vessels increased 20% by day 5 in EVE versus control. Collagen composition showed no difference in scar index analysis. Conclusion: EVE temporarily augments radiation-induced hypo-perfusion, likely due to transient edema. Fibrosis remained unchanged after EVE, possibly accounting for the limited expansion seen in patients. It appears that EVE induces angiogenic effect but does not affect dermal collagen composition. Future efforts should focus on reducing fibrosis post radiation to allow EVE to achieve its full potential, to benefit irradiated patients

Rab11 and Actin Cytoskeleton Participate in Giardia lamblia Encystation, Guiding the Specific Vesicles to the Cyst Wall

The encystation process is crucial for survival and transmission of Giardia lamblia to new hosts. During this process, vesicular trafficking and the cytoskeleton play important roles. In eukaryotic cells, intracellular transport is regulated by proteins, including Rab-GTPases and SNAREs, which regulate vesicle formation along with recognition of and binding to the target membrane. Cytoskeletal structures are also involved in these processes. In this study, we demonstrate the participation of Rab11 in the transport of encystation-specific vesicles (ESVs). Additionally, we demonstrate that disruption of actin microfilaments affects ESVs transport. The modification of actin dynamics was also correlated with a reduction in rab11 and cwp1 expression. Furthermore, down-regulation of rab11 mRNA by a specific hammerhead ribozyme caused nonspecific localization of CWP1. We thus provide new information about the molecular machinery that regulates Giardia lamblia encystation. Given our findings, Rab11 and actin may be useful targets to block Giardia encystation

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO

Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO