265 research outputs found
Lotus petal flap and vertical rectus abdominis myocutaneous flap in vulvoperineal reconstruction:a systematic review of differences in complications
Background Vulvoperineal defects resulting from surgical treatment of (pre)malignancies may result in reconstructive challenges. The vertical rectus abdominis muscle flap and, more recently, the fasciocutaneous lotus petal flap are often used for reconstruction in this area. The goal of this review is to compare the postoperative complications of application of these flaps.Methods:A comprehensive literature search of the PubMed, MEDLINE and Cochrane Library databases was performed until 6 June 2020. Search terms included the lotus petal flap, vertical rectus abdominis muscle flap and the vulvoperineal area. Articles were independently screened by two researchers according to the PRISMA-guidelines.Results:A total of 1074 citations were retrieved and reviewed, of which 55 were included for full text analysis. Following lotus petal flap reconstructions, the complication rate varied from 0.0% to 69.9%, with more complications concerning the recipient site compared with the donor site complications (26.0% versus 4.5%). Following vertical rectus abdominis muscle flap reconstructions the complication rate varied between 0.0% and 85.7% with almost twice the number of recipient site complications compared to donor site complications (37.1% versus 17.8%).Conclusions:Overall, the lotus petal flap has lower complication rates at both the donor and the recipient site compared with the vertical rectus abdominis muscle flap. When both options seem viable, the lotus petal flap procedure may be preferred on the basis of the reported lower complication rates
Quality of Life, Sexual Functioning, and Physical Functioning Following Perineal Reconstruction with the Lotus Petal Flap
BACKGROUND: Lotus petal flaps (LPF) may be used for the reconstruction of extralevator abdominoperineal defects that cannot be closed primarily. Limited data are available on how perineal reconstruction with the LPF impacts on patients' quality of life (QoL), sexual functioning, and physical functioning. METHODS: A cross-sectional study was performed following perineal reconstruction with the LPF. The QoL of patients having undergone LPF reconstruction was compared with a control group in which perineal defects were closed without flaps. Sexual and physical functioning (presence of perineal herniation and range of motion [ROM] of the hip joints) could only be evaluated in the LPF group. Psychometrically sound questionnaires were used. Physical functioning was evaluated subjectively with binary questions and objectively by physical examination. RESULTS: Of the 23 patients asked to participate, 15 (65%) completed the questionnaires and 11 (47%) underwent physical examination. In the control group, 16 patients were included. There were no significant differences in QoL between the LPF and control groups. Within the LPF group, 33% of patients were sexually active postoperatively compared with 87% preoperatively. No perineal herniation was found. The ROM of the hip joints was bilaterally smaller compared with the generally accepted values. CONCLUSIONS: Conclusions should be made with care given the small sample size. Despite a supposedly larger resection area in the LPF group, QoL was comparable in both groups. Nonetheless, reconstruction seemed to affect sexual function and physical function, not hampering overall satisfaction
Oral oxycodone-induced respiratory depression during normocapnia and hypercapnia: a pharmacokinetic-pharmacodynamic modeling study
The widely prescribed opioid oxycodone may cause lethal respiratory depression. We compared the effects of oxycodone on breathing and antinociception in healthy young volunteers. After pharmacokinetic/pharmacodynamic (PK/PD) modeling, we constructed utility functions to combine the wanted and unwanted end points into a single function. We hypothesized that the function would be predominantly negative over the tested oxycodone concentration range. Twenty-four male and female volunteers received 20 (nΒ =Β 12) or 40 (nΒ =Β 12) mg oral oxycodone immediate-release tablets. Hypercapnic ventilatory responses (visit 1) or responses to 3 nociceptive assays (pain pressure, electrical, and thermal tests; visit 2) were measured at regular intervals for 7βhours. the PK/PD analyses, that included carbon dioxide kinetics, stood at the basis of the utility function: probability of antinociception minus probability of respiratory depression. Oxycodone had rapid onset/offset times (30β40βminutes) with potency values (effect-site concentration causing 50% of effect) ranging from 0.05 to 0.13βng/mL for respiratory variables obtained at hypercapnia and antinociceptive responses. Ventilation at an extrapolated end-tidal carbon dioxide partial pressure of 55βmmHg, was used for creation of 3 utility functions, one for each of the nociceptive tests. Contrary to expectation, the utility functions were close to zero or positive over the clinical oxycodone concentration range. The similar or better likelihood for antinociception relative to respiratory depression may be related to oxycodone's receptor activation profile or to is high likeability that possibly alters the modulation of nociceptive input. Oxycodone differs from other ΞΌ-opioids, such as fentanyl, that have a consistent negative utility. Perioperative Medicine: Efficacy, Safety and Outcome (Anesthesiology/Intensive Care
Engineering key components in a synthetic eukaryotic signal transduction pathway
Signal transduction underlies how living organisms detect and respond to stimuli. A goal of synthetic biology is to rewire natural signal transduction systems. Bacteria, yeast, and plants sense environmental aspects through conserved histidine kinase (HK) signal transduction systems. HK protein components are typically comprised of multiple, relatively modular, and conserved domains. Phosphate transfer between these components may exhibit considerable cross talk between the otherwise apparently linear pathways, thereby establishing networks that integrate multiple signals. We show that sequence conservation and cross talk can extend across kingdoms and can be exploited to produce a synthetic plant signal transduction system. In response to HK cross talk, heterologously expressed bacterial response regulators, PhoB and OmpR, translocate to the nucleus on HK activation. Using this discovery, combined with modification of PhoB (PhoB-VP64), we produced a key component of a eukaryotic synthetic signal transduction pathway. In response to exogenous cytokinin, PhoB-VP64 translocates to the nucleus, binds a synthetic PlantPho promoter, and activates gene expression. These results show that conserved-signaling components can be used across kingdoms and adapted to produce synthetic eukaryotic signal transduction pathways
Global Kidney Exchange: Analysis and Background Papers from the Perspective of Medical Anthropology
Global Kidney Exchange (GKE) is a program aimed at facilitating trans-national kidney donation. Although its proponents aim at reducing the unmet demand of kidneys in the United States through the trans-nationalization of kidney exchange programs, the World Health Organization (WHO) and The Transplantation Society (TTS) have expressed concerns about its potential effect on black markets of organs and transnational organ trafficking, as well as on low- or middle-income countries health systems. For GKE to be implemented, it would need to be permitted to operate in at least some low- or middle-income countries. Should a low- or middle-income country allow GKEβs implementation?
With the aim of answering this question, the eighteen University of Denver students in the Medical Anthropology course I [Alejandro CerΓ³n] taught in autumn 2017, identified and researched the different aspects that would affect this issue, and delved in a holistic analysis we present in this report.
Based on our analysis, health authorities in low- or middle-income countries faced with decisions about GKE need to consider the following aspects: the countryβs current and projected needs related to kidney transplant, as well as the capacity for addressing those needs; the countryβs current situation related to organ trafficking, transplant tourism and black markets of organs; the current and projected legislation related to both organ donation and human trafficking; the prevailing ethical considerations that inform the practice of all professionals related to organ transplant in the country; analyze end-stage renal failure as a preventable disease needing public health measures; and the sociocultural aspects that surround organ donation in the country. We consider that the concrete configuration of these aspects would influence the effects of implementing GKE. Additionally, we identified some issues of concern that are beyond the level of influence of local authorities: the unmet demand of kidneys in high-income countries is a reality that incentivizes organ trade and transplant tourism, and this is a problem in need of solutions; transnational organ trafficking as well as human trafficking with the purpose of organ donation are problems that need more visibility; for a global exchange of organs to be implemented, it would need to rely on supranational or transnational regulation and oversight; and the global epidemic of chronic kidney disease needs to be addressed through a public health perspective that emphasizes prevention
Maternal diet and human milk composition: an updated systematic review
CONTEXT: Exclusive breastfeeding for 6βmonths after birth provides infants with the best start for life. A review by Bravi et al. summarized the importance of maternal diet as a determinant of human milk composition based on data up to 2015, but evidence on nutrient intake level was limited. OBJECTIVE: We updated the review by Bravi et al., critically assessed differences in study designs and sampling methods, and graphically visualized trends and associations. DATA SOURCES: PubMed was systematically searched for articles published between January 2015 and March 2021. DATA EXTRACTION: Article screening, selection, and data extraction was done by two independent researchers, including a risk of bias assessment based on 11 criteria. Articles were eligible when including: quantitative information, commonly used effect estimates, healthy mother-infant dyads. RESULTS: Twenty seven observational and five intervention studies were identified ( n β=β7,138) and combined with results of Bravi et al. Fatty acids were still the most studied human milk components in relation to maternal diet ( n β=β17 studies) with maternal fish intake being predominantly positively associated with milk ALA ( r β=β0.28-0.42), DHA ( r β=β0.24-0.46), and EPA ( r β=β0.25-0.28) content. PUFAs from diet were generally positively correlated with their concentrations in milk, while SFA intake was negatively associated with several fatty acids in milk. Studies on associations with maternal diet and milk carbohydrates, proteins, vitamins and minerals were limited in number and varied in methods and results. CONCLUSION: This updated review shows that evidence on the association between maternal diet and human milk fatty acids is rapidly increasing, but still diversified in methodology and results. Further studies, preferably intervention studies, assessing diet and milk carbohydrates, proteins, vitamins and minerals are needed to be able draw conclusions on the importance of maternal diet for human milk composition as a whole
Inferring stabilizing mutations from protein phylogenies : application to influenza hemagglutinin
One selection pressure shaping sequence evolution is the requirement that a protein fold with sufficient stability to perform its biological functions. We present a conceptual framework that explains how this requirement causes the probability that a particular amino acid mutation is fixed during evolution to depend on its effect on protein stability. We mathematically formalize this framework to develop a Bayesian approach for inferring the stability effects of individual mutations from homologous protein sequences of known phylogeny. This approach is able to predict published experimentally measured mutational stability effects (ΞΞG values) with an accuracy that exceeds both a state-of-the-art physicochemical modeling program and the sequence-based consensus approach. As a further test, we use our phylogenetic inference approach to predict stabilizing mutations to influenza hemagglutinin. We introduce these mutations into a temperature-sensitive influenza virus with a defect in its hemagglutinin gene and experimentally demonstrate that some of the mutations allow the virus to grow at higher temperatures. Our work therefore describes a powerful new approach for predicting stabilizing mutations that can be successfully applied even to large, complex proteins such as hemagglutinin. This approach also makes a mathematical link between phylogenetics and experimentally measurable protein properties, potentially paving the way for more accurate analyses of molecular evolution
Locally advanced and recurrent cancer
A successful treatment of locally advanced and recurrent rectal cancer is based on the responsibility of the surgeon to perform a radical resection. Planning of treatment starts with imaging with a pelvic MRI and a CT scan of chest and the abdomen. Neoadjuvant chemoradiation is given to achieve downstaging and downsizing. After a waiting period of at least 6 weeks, a total mesorectal excision is performed with often an extra-anatomical extension based on the initial imaging. Reconstruction using several types of pedicled flaps is often necessary to close the defect of the pelvic floor.</p
PROTDES: CHARMM toolbox for computational protein design
We present an open-source software able to automatically mutate any residue positions and find the best aminoacids in an arbitrary protein structure without requiring pairwise approximations. Our software, PROTDES, is based on CHARMM and it searches automatically for mutations optimizing a protein folding free energy. PROTDES allows the integration of molecular dynamics within the protein design. We have implemented an heuristic optimization algorithm that iteratively searches the best aminoacids and their conformations for an arbitrary set of positions within a structure. Our software allows CHARMM users to perform protein design calculations and to create their own procedures for protein design using their own energy functions. We show this by implementing three different energy functions based on different solvent treatments: surface area accessibility, generalized Born using molecular volume and an effective energy function. PROTDES, a tutorial, parameter sets, configuration tools and examples are freely available at http://soft.synth-bio.org/protdes.html
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