Baseline Methods for the Parameter Estimation of the Generalized Pareto Distribution.

In the parameter estimation of limit extreme value distributions, most employed methods only use some of the available data. Using the peaks-over-threshold method for Generalized Pareto Distribution (GPD), only the observations above a certain threshold are considered; therefore, a big amount of information is wasted. The aim of this work is to make the most of the information provided by the observations in order to improve the accuracy of Bayesian parameter estimation. We present two new Bayesian methods to estimate the parameters of the GPD, taking into account the whole data set from the baseline distribution and the existing relations between the baseline and the limit GPD parameters in order to define highly informative priors. We make a comparison between the Bayesian Metropolis-Hastings algorithm with data over the threshold and the new methods when the baseline distribution is a stable distribution, whose properties assure we can reduce the problem to study standard distributions and also allow us to propose new estimators for the parameters of the tail distribution. Specifically, three cases of stable distributions were considered: Normal, Lévy and Cauchy distributions, as main examples of the different behaviors of the tails of a distribution. Nevertheless, the methods would be applicable to many other baseline distributions through finding relations between baseline and GPD parameters via studies of simulations. To illustrate this situation, we study the application of the methods with real data of air pollution in Badajoz (Spain), whose baseline distribution fits a Gamma, and show that the baseline methods improve estimates compared to the Bayesian Metropolis-Hastings algorithm.

Endonuclease-based genotyping of the RBM, a first-line method for the surveillance of emergence or evolution of SARS-CoV-2 Variants.

Since the beginning of the Covid-19 pandemics, variants have emerged. Whereas most of them have no to limited selective advantage, some display increased transmissibility and/or resistance to immune response. To date, most of the mutations involved in the functional adaptation are found in the Receptor Binding Module (RBM), close to the interface with the human receptor ACE2. In this study, we thus developed and validated a fast and simple molecular assay allowing the detection and partial identification of the mutations in the RBM coding sequence. After the amplification of the region of interest, the amplicon is heat-denatured and hybridized with an amplicon of reference. The presence of a mutation in the heteroduplex can be cleaved by a mismatch-specific endonuclease and the cleavage pattern is analysed by capillary electrophoresis. The approach was first validated on viral RNA purified different SARS-CoV-2 variants produced in the lab before being implemented for clinical samples. The results highlighted the performance of the assay for the detection of mutations in the RBM from clinical samples. The procedure can be easily set up for high throughput identification of the presence of mutations and serve as a first-line screening to select the samples for full genome sequencing.

Autologous Fat Grafting with Percutaneous Fasciotomy and Reduction of the Nipple-Areolar Complex for the Correction of Tuberous Breast Deformity in Teenagers.

BACKGROUND: Tuberous breast deformity in the adolescent can be a source of anxiety and social isolation. Current techniques of implant placement and flap reconstruction are not always feasible in this population. OBJECTIVES: The authors evaluated the use of autologous fat grafting with percutaneous fasciotomy and reduction in the nipple-areolar complex for correction of tuberous breast deformity in teenagers. METHODS: A retrospective chart review was conducted for nine teenaged patients with tuberous breast deformity who received autologous fat grafting between January 2016 and December 2018. The recipient site was prepared with the use of percutaneous fasciotomies to release the constricted lower pole of the breast, lowering of the inframammary crease, and reduction in the nipple-areolar complex. Fat was harvested by conventional liposuction prior to injection through three designated sites located at the inframammary fold, anterior axillary line, and upper pole. Complications were recorded. RESULTS: Patients had an average age of 14.9 years at the time of surgery. An average of 1.8 filling sessions were required with a mean of 220 cc of fat injected per breast. Patients were followed for an average of 21 months postoperatively. No serious complications were noted. All patients reported satisfaction with their final outcomes. CONCLUSIONS: Autologous fat grafting in conjunction with percutaneous fasciotomy and reduction in the nipple-areolar complex is a safe and effective treatment of the tuberous breast deformity in teenage patients. It provides an esthetic result with minimal scarring and high satisfaction rates while eliminating the need for flaps or implants. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Long-term follow-up of myelomeningocele defect closure with dorsal intercostal artery perforator propeller flaps.

BACKGROUND: Closure of the skin defect in myelomeningocele repair determines the quality of the surgical result. In large myelomeningoceles, the direct closure or by skin undermining may not be possible. In these cases, the skin defect must be closed using flaps to provide a tension-free and successful closure. METHODS: In this procedure, after neurosurgical repair and closure of the placode, the defect surgically becomes an ovoid in shape. Then, this defect is closed by transposition of two dorsal intercostal artery perforator propeller flaps. The defect size was > 5 cm in diameter. The localization of the lesion was lumbosacral. RESULT: A successful tension-free one-stage closure was obtained, without necrosis. Healing was uneventful without any complications and the coverage remained stable over 9 years with the child growth. CONCLUSION: The dorsal intercostal artery perforator propeller flap enables the surgeon to achieve a tension-free defect closure of considerably large myelomeningocele defects. This type of closure provides a durable coverage and a soft tissue padding over the neural tissues that persist with the child growth. The dorsal intercostal artery perforator propeller flap seems to be a useful closure of large myelomeningocele defects.

Antiagregation and anticoagulation, relationship with upper gastrointestinal bleeding.

INTRODUCTION: the high prevalence of cardiovascular diseases in the modern society brings a high prescription of platelet antiaggregation and anticoagulant medications. These treatments have been related to an increased incidence of upper gastrointestinal bleedings (UGB). Our aim was to estimate the fraction of UGB´s presented to our hospital that was related to this kind of treatments and describe their clinical features in our environment. MATERIAL AND METHODS: a retrospective search was performed in the archives of our hospital of all the patients with diagnosis of UGB admitted during the period 2004-2007 both years inclusive. Patients on antiplatelet and/or anticoagulant treatment were included. We analyzed the information regarding the use of medication, the bleeding lesion, the severity of the bleeding, recurrences, mortality and their clinical features. RESULTS: we found 523 episodes of UGB. Of these 137 (26.1%) were patients receiving platelet antiaggregation or anticoagulant drugs. The patients were male 60.2%, and had a mean age of 75.6 (± 10.8) years. The 65.5% (74) had HBP, 43.4% (49) diabetes mellitus and 37.2% (42) dislypemia and 13.3% (22) dementia.The drug most frequently implicated was ASA in 36.3% (41), followed by acenocumarol in 27.4% (31), clopidogrel 18.6% (21), double therapy (ASA + clopidogrel) in 6.2% (7), triple therapy (ASA + clopidogrel + acenocumarol) in 0.9% (1), triflusal 4.4% (5), low molecular weight heparin 5.3% (5), and ticlopidine in one patient (0.9%). Only 36.3% (41) were on treatment with proton pump inhibitors. There were 24 recurrences and 4 deaths. CONCLUSIONS: the 26.1% of the UGB attended in our environment were of iatrogenic origin. We also found a low use of proton pump inhibitors.