Phytate Dephosphorylation Products Also Act as Potent Inhibitors of Calcium Oxalate Crystallization.

Phytate has been classified as an anti-nutrient, but there are no adverse effects from the consumption of a balanced diet with 1 to 2 g of daily phytate (inositol-hexaphosphate, InsP6) as a calcium magnesium salt, the form naturally present in grains. Furthermore, recent research has shown that phytate consumption may prevent pathological calcifications, such as kidney stones and cardiovascular calcifications. However, many endogenous and exogenous enzymes can hydrolyze phytate to lower inositol phosphates (InsPs) that also have biological activity. We performed a controlled hydrolysis of phytate and identified the products (InsPs) using tandem mass spectrometry (MS/MS). The total level of all InsPs was measured using a non-specific methodology. In addition, we evaluated the effects of the InsP6 hydrolysates on calcium oxalate crystallization using scanning electron microscopy and measuring the time needed for the induction of crystallization. Our results indicate that InsP6 and its hydrolysis products functioned as effective inhibitors of calcium oxalate crystallization. Thus, even though InsP6 is hydrolyzed after consumption, the enzymatic products also have the potential to reduce pathological calcifications. Finally, although it is useful to measure the overall level of InsPs in biological fluids, such as urine, there is a need to develop simple analytical methods to quantify the level of individual InsPs.

Use of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry Analysis of Serum Peptidome to Classify and Predict Coronavirus Disease 2019 Severity.

BACKGROUND: Classification and early detection of severe coronavirus disease 2019 (COVID-19) patients is required to establish an effective treatment. We tested the utility of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to classify and predict the severity of COVID-19. METHODS: We used MALDI-TOF MS to analyze the serum peptidome from 72 patients with COVID-19 (training cohort), clinically classified as mild (28), severe (23), and critical (21), and 20 healthy controls. The resulting matrix of peak intensities was used for Machine Learning (ML) approaches to classify and predict COVID-19 severity of 22 independent patients (validation cohort). Finally, we analyzed all sera by liquid chromatography mass spectrometry (LC-MS/MS) to identify the most relevant proteins associated with disease severity. RESULTS: We found a clear variability of the serum peptidome profile depending on COVID-19 severity. Forty-two peaks exhibited a log fold change ≥1 and 17 were significantly different and at least 4-fold more intense in the set of critical patients than in the mild ones. The ML approach classified clinical stable patients according to their severity with 100% accuracy and correctly predicted the evolution of the nonstable patients in all cases. The LC-MS/MS identified 5 proteins that were significantly upregulated in the critical patients. They included the serum amyloid protein A2, which probably yielded the most intense peak detected by MALDI-TOF MS. CONCLUSIONS: We demonstrate the potential of the MALDI-TOF MS as a bench to bedside technology to aid clinicians in their decision making regarding patients with COVID-19.

Microscale extraction versus conventional approaches for handling gastrointestinal extracts in oral bioaccessibility assays of endocrine disrupting compounds from microplastic contaminated beach sand.

The unified bioaccessibility method (UBM) was harnessed to assess in vitro oral bioaccessibility pools of dialkyl phthalate congeners (with methyl, -ethyl, -butylbenzyl, -n-butyl, -2-ethylhexyl, and -n-octyl moieties) and bisphenol A at the 17 µg g-1 level in beach sand contaminated with polyethylene microplastics. A variety of sample preparation approaches prior to the analysis of the UBM gastrointestinal extracts, including traditional methods (protein precipitation, liquid-liquid extraction, and solid-phase extraction) and dispersive liquid-liquid microextraction (DLLME) were comprehensively evaluated for clean-up and analyte enrichment. DLLME was chosen among all tested approaches on account of the high extraction efficiency (73-95%, excluding bis(2-ethylhexyl)phthalate and di-n-octyl phthalate), high sample throughput (∼7 min per set of samples), and environmental friendliness as demonstrated by the analytical eco-scale score of 83, and the green analytical procedure index pictogram with green/yellow labeling. The release of the less hydrophobic plastic-laden compounds (dimethyl phthalate, diethyl phthalate and bisphenol A) from the contaminated sample into the body fluids was significant, with bioaccessibility values ranging from 30 to 70%, and from 43 to 74% in gastric and gastrointestinal fluids, respectively, and with relative standard deviation < 17% in all cases. The majority of the compounds were leached during gastric digestion, likely as the combined action of the low pH and the gastric enzymes. The risk exposure analysis revealed that accumulation/concentration in the body fluids is potentially relevant for dimethyl phthalate, diethyl phthalate and bisphenol A, with relative accumulation ratios ranging from 1.1 ± 0.1 to 2.6 ± 0.4. The average daily intake values for the suite of compounds, corrected with the bioaccessibility fraction, ranged from 60 to 430 ng kg of body weight-1·day-1, in all cases, far below the tolerable daily intakes, thus indicating the lack of children health risk by ingestion of microplastic-laden sand with elevated concentrations of plasticizers.

Automatic Mesofluidic System Combining Dynamic Gastrointestinal Bioaccessibility with Lab-on-Valve-Based Sorptive Microextraction for Risk Exposure of Organic Emerging Contaminants in Filter-Feeding Organisms.

An automatic mesofluidic system combining dynamic oral bioaccessibility with lab-on-valve (LOV)-based sorptive microextraction is herein proposed for the first time for exploring the kinetics of leaching of incurred rather than spiked organic emerging contaminants (viz., methyl paraben, butyl paraben, diclofenac, and triclosan) from exposed mussels on the basis of the Versantvoort's fed-state physiological extraction test. Our method capitalizes on programmable flow analysis, in which gastrointestinal extracts are obtained online by pumping a simulated biorelevant gastrointestinal fluid across a large-bore column (maintained at 37.0 ± 2.0 °C) loaded with 250 mg of freeze-dried and powdered mussel onto a polyvinyldiene difluoride filter membrane. The physiologically relevant extracts are then cleaned up, and the analytes are preconcentrated onto a dedicated reversed-phase solid-phase extraction (Oasis PRIME-HLB) microcolumn that is captured into the channels of an LOV mesofluidic platform. The aim behind this is to obtain analyte-laden eluates with ACN/MeOH (90:10, v/v) in unsupervised mode for direct injection into LC-MS. The LOV minicolumn (≤25 mg) is automatically disposed of and renewed for every individual fraction on account of the strong retention of (phospho)lipids by the copolymeric sorbent. The proposed dynamic bioaccessibility test features a significant shortening of the extraction time against the batch method (28 vs 240 min) while avoiding overestimation of potentially bioavailable fractions. The trueness of the online gastrointestinal extraction method was confirmed using mass-balance validation following ultrasonic-assisted solid-liquid extraction of the original mussel sample and the residual (nonbioaccessible) fraction of emerging contaminants.

Quantification of xanthine- and uric acid-related compounds in urine using a "dilute-and-shoot" technique coupling ultra-high-performance liquid chromatography and high-resolution Orbitrap mass spectrometry.

Quantitative analysis of relevant metabolites in biofluids such as urine is often a tedious procedure, since it usually requires extraction, purification or preconcentration. For instance, in the analysis of methylxanthines in urine, a solid-phase extraction is often required. In the current work, a rapid and highly sensitive "dilute-and-shoot" method combining ultra-high-performance liquid chromatography and high-resolution mass spectrometry (UHPLC/HRMS) was validated for urinary determination of twelve analytes: uric acid, hypoxanthine, xanthine, 1-methyluric acid, 1,3-dimethyluric acid, 1-methylxanthine, 3-methylxanthine, 7-methylxanthine, theophylline, theobromine, paraxanthine and caffeine. These analytes are the major physiological metabolites of caffeine, theobromine or theophylline, or final products of purine catabolism. The separation was carried out on a core-shell Kinetek EVO C18 column coupled to a Q Exactive Orbitrap high-resolution mass spectrometer equipped with a heated electrospray ionization (HESI) probe, that operated both in positive and negative ionization modes. The twelve analytes eluted from between 1.5 and 10.5min. The lower limit of quantification (LLOQ) values ranged from 0.25 to 2.5ng/mL, and the calibration curves were linear from the LLOQ to 100ng/mL. The only pretreatment needed was to dilute each urine sample (typically to 1/500) with 0.1% formic acid solution, and then filter the diluted sample before injecting it into the UHPLC system. With this high dilution, there were no significant matrix effects, and the intra- and inter-day precision and accuracy values were acceptable (coefficients of variance and relative errors below 15%, except for the LLOQ, for which they were below 20%). Furthermore, the analysis of spiked urine samples with 25ng/mL of the target analytes showed excellent recoveries and precision levels for the twelve analytes. To our knowledge, there is no other published method that allows for the simultaneous determination of the concentrations of these twelve compounds, nor has a previously reported method been indicated to show such low LLOQ values as we have for the majority of the analytes. We expect our protocol to be useful for nutritional assessments, interventional studies, kidney stone research, and purine metabolism studies.

Measurements of Electron Partitioning Between Cytochrome and Alternative Oxidase Pathways in Plant Tissues.

Plant respiration is characterized by the existence of the alternative oxidase pathway (AOP) that competes with cytochrome oxidase pathway (COP) for the electrons of the ubiquinone pool of the mitochondrial electron transport chain, thus reducing ATP synthesis. The oxygen (O2) isotope fractionation technique is the only available to determine the electron partitioning between the two pathways and their in vivo activities in plant tissues. In this chapter, the basis of the O2 isotope fractionation technique and its derived calculations are carefully explained together with a detailed description of the dual-inlet isotope ratio mass spectrometry (DI-IRMS) system and the protocol developed at the University of Balearic Islands. The key advantages of the DI-IRMS over other systems are highlighted as well as the potential problems of this technique. Among these problems, those associated with leakage, diffusion, and inhibitor treatments are noted and solutions to prevent, detect, and repair these problems are detailed.

Skin staples versus intradermal wound closure following primary hip arthroplasty: a prospective, randomised trial including 231 cases.

Intradermal wound closure is controversial in primary total hip arthroplasty. Randomised, controlled trials in wound closure following a total hip arthroplasty (THA) are scarce. Our hypothesis was that skin staples closure would be related to a similar complication rate and operative time as intradermal closure with polypropylene. From September 2011 to May 2012, 231 THAs in 219 patients with an average age of 62 years old (range: 21-91) were performed. No differences were observed in both groups according to sex, age, BMI and comorbidities (p = 0,82). Cases were divided into 3 groups according to medical factors that influence wound healing: group 1 (no medical history, 70.5%), group 2 (diabetes, tobacco smokers, obesity, corticosteroids, rheumatoid disease, 25%) and group 3 (organ transplantation, neoplastic patients or 2 or factors of group 2, 4.5%). Once randomised using a computer-generated method, all patients remained within the group to which they were allocated to wound closure with skin staples (Leukosan® SkinStapler PTW-35, BSN, Germany) that were used in 112 THAs in 105 patients (48%), or continuous 3.0 intradermal non-absorbable polypropylene suture (Prolene™ 0, Ethicon Inc. Somerville, New Jersey, USA) in 119 THA´s in 115 patients (52%). A 3.8% wound complication rate was observed in this series, with a 2.1% complication rate for the group that was closed with skin staples and a 1.7% rate for the group with intradermal suture (p = 0.7). All the complications were treated conservatively except for one acute deep infection (0.4%) that was successfully treated with debridement, component retention and intravenous antibiotics. There were no differences in both groups related to operative time or wound length.In these series of primary elective THAs, skin staples were associated with a similar complication rate to an intradermal closure technique.

Hydrogen Bonded Squaramide-Based Foldable Module Induces Both ß- and α-Turns in Hairpin Structures of α-Peptides in Water.

A novel tertiary squaramido-based reverse-turn module SQ is reported, and its conformational properties are evaluated. This module is easily incorporated into a α-peptide sequence by conventional solid-phase peptide synthesis. The structure characterization of the hybrid squaramido-peptide 4 is described, showing that the turn segment induces the formation of hairpin structures in water through the formation of both αSQ- and ßSQ-turns.

Intraoperative synovial C-reactive protein is as useful as frozen section to detect periprosthetic hip infection.

BACKGROUND: Synovial quantification of C-reactive protein (SCRP) has been recently published with high sensitivity and specificity in the diagnosis of periprosthetic joint infection. However, to our knowledge, no studies have compared the use of this test with intraoperative frozen section, which is considered by many to be the best intraoperative test now available. QUESTIONS/PURPOSES: We asked whether intraoperative SCRP could lead to comparable sensitivity, specificity, and predictive values as intraoperative frozen section in revision total hip arthroplasty. METHODS: A prospective study was performed including 76 patients who underwent hip revision for any cause. SCRP quantification (using 9.5 mg/L as denoting infection) and the analysis of frozen section of intraoperative samples (five or more polymorphonuclear leukocytes under high magnification in 10 fields) were performed in all the patients. The definitive diagnosis of an infection was determined according to the Musculoskeletal Infection Society (MSIS). In this group, 30% of the patients were diagnosed with infection using the MSIS criteria (23 of 76 patients). RESULTS: With the numbers available, there were no differences between SCRP and frozen section in terms of their ability to diagnose infection. The sensitivity of SCRP was 90% (95% confidence interval [CI], 70.8%-98.6%), the specificity was 94% (95% CI, 84.5%-98.7%), the positive predictive value was 87% (95% CI, 66.3%-97%), and the negative predictive value was 96% (95% CI, 87%-99.4%); the sensitivity, specificity, positive predictive value, and negative predictive value were the same using frozen sections to diagnose infection. The positive likelihood ratio was 16.36 (95% CI, 5.4-49.5), indicating a low probability of an individual without the condition having a positive test, and the negative likelihood ratio was 0.10 (95% CI, 0.03-0.36), indicating low probability of an individual without the condition having a negative test. CONCLUSIONS: We found that quantitative SCRP had similar diagnostic value as intraoperative frozen section with comparable sensitivity, specificity, and predictive value in a group of patients undergoing revision total hip arthroplasty. In our institution, SCRP is easier to obtain, less expensive, and less dependent on the technique of obtaining and interpreting a frozen section. If our findings are confirmed by other groups, we suggest that quantitative SCRP be considered as a viable alternative to frozen section. LEVEL OF EVIDENCE: Level I, diagnostic study.

Programmed enzyme-mimic hydrolysis of a choline carbonate by a metal-free 2-aminobenzimidazole-based cavitand.

The hydrolysis of a choline carbonate through a metal-free, enzyme-like mechanism has been achieved using a 2-aminobenzimidazole-based deep cavitand as catalyst. The supramolecular catalysis involves three steps: host-guest binding, carbamoylation and enzyme-like hydrolysis. Interestingly the rate-determining step proceeds through a programmed hydrolysis of carbamoylcholine-cavitand intermediate that may be driven by water molecules surrounding the benzimidazole walls of the cavity.

Trapping a salt-dependent unfolding intermediate of the marginally stable protein Yfh1.

Yfh1, the yeast ortholog of frataxin, is a protein of limited thermodynamic stability which undergoes cold denaturation at temperatures above the water freezing point. We have previously demonstrated that its stability is strongly dependent on ionic strength and that monovalent or divalent cations are able to considerably stabilize the fold. Here, we present a study of the folded state and of the structural determinants that lead to the strong salt dependence. We demonstrate by nuclear magnetic resonance that, at room temperature, Yfh1 exists as an equilibrium mixture of a folded species and a folding intermediate in slow exchange equilibrium. The equilibrium completely shifts in favor of the folded species by the addition of even small concentrations of salt. We demonstrate that Yfh1 is destabilized by a localized energetic frustration arising from an "electrostatic hinge" made of negatively charged residues mapped in the ß-sheet. Salt interactions at this site have a "frustration-relieving" effect. We discuss the consequences of our findings for the function of Yfh1 and for our understanding of protein folding stability.

Condromatosis sinovial de cadera. Tratamiento artroscópico / Hip synovial chondromatosis. Arthroscopic treatment

Introducción: La condromatosis sinovial se define como una lesión metaplásica benigna, de baja incidencia en cadera. La técnica ideal de tratamiento genera controversia por la probable recurrencia y la progresión degenerativa descrita para técnicas tanto a cielo abierto como artroscópicas. El objetivo de este trabajo es reportar la técnica quirúrgica y los resultados a corto plazo en una serie de pacientes con condromatosis sinovial de cadera tratados por vía artroscópica. Materiales y Métodos: Entre abril de 2007 y mayo de 2011, 10 pacientes (9 mujeres y 1 hombre, edad promedio 38 años; rango 17-53) fueron operados por vía artroscópica a causa de una condromatosis sinovial de cadera. Se evaluaron la técnica quirúrgica, los resultados clínicos y radiológicos, y el grado de satisfacción con el procedimiento. La escala funcional de Harris modificada preoperatoria fue de 51 puntos (rango 49-54). La histología diferida confirmó el diagnóstico en todos los casos. El seguimiento prospectivo fue, en promedio, de 35 meses (rango 24-47). Resultados: En todos los casos, se realizó una técnica artroscópica convencional para extraer cuerpos libres y sinovectomía parcial anterolateral. En tres pacientes, se amplió la incisión de uno de los portales para extraer cuerpos de gran diámetro. La escala funcional de Harris modificada posoperatoria fue, en promedio, de 88 puntos (rango 85-91). No se observó progreso degenerativo articular radiológico en el último control. Todos los pacientes se mostraron satisfechos con el procedimiento. No se registraron complicaciones. Conclusiones: Los resultados a corto plazo favorables coinciden con los publicados. Los pacientes con condromatosis sinovial de cadera pueden ser tratados por vía artroscópica en forma segura y eficaz. Diseño del estudio: Estudio terapéutico Nivel de evidencia: IV...(AU)

Background: Synovial chondromatosis is defined as a benign metaplastic lesion, with a low incidence in hips. The ideal treatment technique is controversial due to the probable recurrence and degenerative progression described with both arthroscopic and open surgery. The aim of this study is to report the surgical technique and shortterm results in a series of patients with synovial chondromatosis treated with arthroscopic hip. Methods: From April 2007 to May 2011, 10 patients (9 women and a man; average age 38 years; range 17-53) underwent hip arthroscopy for synovial chondromatosis. Surgical technique, clinical and radiological results, and satisfaction with the procedure were evaluated. The preoperative modified Harris hip functional scale was 51 points (range 49-54). Delayed histology confirmed diagnosis in all cases. Prospective follow-up averaged 35 months (range 24-47). Results: The conventional arthroscopic technique to extract loose bodies and partial anterolateral synovectomy were performed in all patients. In three patients incision of one of the portals was extended to extract bodies of large diameter. The postoperative modified Harris hip functional scale averaged 88 points (range 85-91). No radiographic joint degenerative progress was seen at the last control. All patients were satisfied with the procedure. There were no complications. Conclusions: Favorable short-term results are consistent with those reported in the literature. Patients with synovial chondromatosis can be treated with hip arthroscopy safely and effectively. Design of the Study: Therapeutic. Level of Evidence: IV...(AU)

Condromatosis sinovial de cadera. Tratamiento artroscópico / Hip synovial chondromatosis. Arthroscopic treatment

Introducción: La condromatosis sinovial se define como una lesión metaplásica benigna, de baja incidencia en cadera. La técnica ideal de tratamiento genera controversia por la probable recurrencia y la progresión degenerativa descrita para técnicas tanto a cielo abierto como artroscópicas. El objetivo de este trabajo es reportar la técnica quirúrgica y los resultados a corto plazo en una serie de pacientes con condromatosis sinovial de cadera tratados por vía artroscópica. Materiales y Métodos: Entre abril de 2007 y mayo de 2011, 10 pacientes (9 mujeres y 1 hombre, edad promedio 38 años; rango 17-53) fueron operados por vía artroscópica a causa de una condromatosis sinovial de cadera. Se evaluaron la técnica quirúrgica, los resultados clínicos y radiológicos, y el grado de satisfacción con el procedimiento. La escala funcional de Harris modificada preoperatoria fue de 51 puntos (rango 49-54). La histología diferida confirmó el diagnóstico en todos los casos. El seguimiento prospectivo fue, en promedio, de 35 meses (rango 24-47). Resultados: En todos los casos, se realizó una técnica artroscópica convencional para extraer cuerpos libres y sinovectomía parcial anterolateral. En tres pacientes, se amplió la incisión de uno de los portales para extraer cuerpos de gran diámetro. La escala funcional de Harris modificada posoperatoria fue, en promedio, de 88 puntos (rango 85-91). No se observó progreso degenerativo articular radiológico en el último control. Todos los pacientes se mostraron satisfechos con el procedimiento. No se registraron complicaciones. Conclusiones: Los resultados a corto plazo favorables coinciden con los publicados. Los pacientes con condromatosis sinovial de cadera pueden ser tratados por vía artroscópica en forma segura y eficaz. Diseño del estudio: Estudio terapéutico Nivel de evidencia: IV...

Background: Synovial chondromatosis is defined as a benign metaplastic lesion, with a low incidence in hips. The ideal treatment technique is controversial due to the probable recurrence and degenerative progression described with both arthroscopic and open surgery. The aim of this study is to report the surgical technique and shortterm results in a series of patients with synovial chondromatosis treated with arthroscopic hip. Methods: From April 2007 to May 2011, 10 patients (9 women and a man; average age 38 years; range 17-53) underwent hip arthroscopy for synovial chondromatosis. Surgical technique, clinical and radiological results, and satisfaction with the procedure were evaluated. The preoperative modified Harris hip functional scale was 51 points (range 49-54). Delayed histology confirmed diagnosis in all cases. Prospective follow-up averaged 35 months (range 24-47). Results: The conventional arthroscopic technique to extract loose bodies and partial anterolateral synovectomy were performed in all patients. In three patients incision of one of the portals was extended to extract bodies of large diameter. The postoperative modified Harris hip functional scale averaged 88 points (range 85-91). No radiographic joint degenerative progress was seen at the last control. All patients were satisfied with the procedure. There were no complications. Conclusions: Favorable short-term results are consistent with those reported in the literature. Patients with synovial chondromatosis can be treated with hip arthroscopy safely and effectively. Design of the Study: Therapeutic. Level of Evidence: IV...

Preservación ósea femoral con tallos cortos de fijación cervicometafisaria. Estudio radiográfico comparativo con tallos no cementados de fijación metafisaria / Femoral bone presevation using short stems with metaphyseal fixation

Introducción: Los tallos no cementados recubiertos con hidroxiapatita de fijación metafisaria han logrado excelentes resultados a largo plazo. La segunda generación de tallos cortos de fijación cervicometafisaria ha surgido a principios de la década de 1990, con el objetivo de preservar capital óseo femoral. Sin embargo, la preservación ósea femoral teóricamente propuesta no ha sido comprobada. El objetivo de este trabajo es determinar radiográficamente la preservación del capital óseo femoral cuando se utilizó un tallo corto de fijación cervicometafisaria, comparando las radiografías posoperatorias con la programación del tallo que se debería haber utilizado en caso de ser un diseño convencional con fijación metafisaria. Materiales y Métodos: Los primeros 50 tallos cortos de fijación cervicometafisaria (MiniHip TM, Corin, Cirencester, Reino Unido) fueron analizados por dos observadores independientes, con radiografías de frente, en cuanto a nivel de resección cervical y longitud del tallo, comparándolos con las filminas de un tallo convencional de fijación metafisodiafisaria (MetaFix TM, Corin, Cirencester, Reino Unido). Resultados: Según el análisis radiográfico, los tallos cortos de fijación cervicometafisaria ocuparon una longitud femoral promedio de 79 mm (rango 68-102). Los tallos convencionales de fijación metafisaria hubiesen ocupado, en promedio, 73 mm más que los tallos cortos (rango 47-94). Esta distribución se observó en el corte de cuello (promedio 10 mm más distal) y en la longitud del implante (promedio 66 mm mayor longitud) (p <0,001). Esta diferencia permite preservar un 42% el capital óseo femoral. Conclusión: La preservación ósea relacionada con el uso de tallos cortos de fijación cervicometafisaria podría traer beneficios a largo plazo en pacientes jóvenes con alta demanda funcional.

Background: Uncemented hydroxyapatite-coated stems with methaphyseal fixation have demonstrated excellent long-term results. Second generation of short stems has been developed in the 90’s with the purpose to preserve femoral bone at the femoral neck and diaphysis. However, the amount of bone that would be theoretically saved has not been well-established. To radiographically determine femoral bone preservation in a series of patients operated on with a short, neck preserving stem, we compared these results with the length of a templated conventional length, uncemented hydroxyapatite-coated stem. Methods: The first 50 short hydroxyapatite-coated uncemented stems (MiniHip TM, Corin, Cirencester, UK) were radiographically analyzed by two independent observers measuring the level of neck cut and the stem length. Then, these results were compared with the level of neck cut and stem length when a conventional, metaphysodiaphyseal stem (MetaFix TM, Corin, Cirencester, UK) was implanted using templates. Results: According to the radiographic results, short stems measured an average length of 79 mm (range 68-102). Conventional stems would have required 78 mm (range 47-94) more bone for fixation than short stems. This difference was observed in the neck cut (average 10 mm more distal with a conventional stems), as well as in the diaphysis (average 66 mm more distal with a conventional stems) (p <0.001). Conclusion: Femoral bone preservation may be related to long-term benefits especially in young patients.

Osteosintesis percutánea anterior en las fracturas diafisarias del húmero / Minimally invasive anterior plate osteosynthesis in humeral shaft fractures

Introducción: Existe controversia en el método ideal de tratamiento de las fracturas del húmero, aunque la reducción abierta y la fijación interna con placa y tornillos es la opción más confiable. El objetivo de este trabajo es describir la técnica quirúrgica, e informar sobre las complicaciones y la tasa de consolidación de la osteosíntesis mínimamente invasiva en esas fracturas. Materiales y métodos: Entre enero de 2008 y diciembre de 2009 fueron tratados 10 pacientes con fracturas del húmero mediante reducción indirecta y fijación interna mínimamente invasiva con placa y tornillos. Resultados: Todos los pacientes fueron seguidos hasta un año después de la cirugía. Todas las fracturas se consolidaron en un promedio de 4 meses. No se produjeron lesiones neurovasculares durante el procedimiento quirúrgico. Conclusiones: La osteosíntesis percutánea utilizando la cara anterior del húmero es segura y eficaz, y es una alternativa para el tratamiento de estas fracturas (AU)

Osteosintesis percutánea anterior en las fracturas diafisarias del húmero / Minimally invasive anterior plate osteosynthesis in humeral shaft fractures

Introducción: Existe controversia en el método ideal de tratamiento de las fracturas del húmero, aunque la reducción abierta y la fijación interna con placa y tornillos es la opción más confiable. El objetivo de este trabajo es describir la técnica quirúrgica, e informar sobre las complicaciones y la tasa de consolidación de la osteosíntesis mínimamente invasiva en esas fracturas. Materiales y métodos: Entre enero de 2008 y diciembre de 2009 fueron tratados 10 pacientes con fracturas del húmero mediante reducción indirecta y fijación interna mínimamente invasiva con placa y tornillos. Resultados: Todos los pacientes fueron seguidos hasta un año después de la cirugía. Todas las fracturas se consolidaron en un promedio de 4 meses. No se produjeron lesiones neurovasculares durante el procedimiento quirúrgico. Conclusiones: La osteosíntesis percutánea utilizando la cara anterior del húmero es segura y eficaz, y es una alternativa para el tratamiento de estas fracturas (AU)

The role of hydration in protein stability: comparison of the cold and heat unfolded states of Yfh1.

Protein unfolding occurs at both low and high temperatures, although in most cases, only the high-temperature transition can be experimentally studied. A pressing question is how much the low- and high-temperature denatured states, although thermodynamically equivalent, are structurally and kinetically similar. We have combined experimental and computational approaches to compare the high- and low-temperature unfolded states of Yfh1, a natural protein that, at physiologic pH, undergoes cold and heat denaturation around 0 °C and 40 °C without the help of ad hoc destabilization. We observe that the two denatured states have similar but not identical residual secondary structures, different kinetics and compactness and a remarkably different degree of hydration. We use molecular dynamics simulations to rationalize the role of solvation and its effect on protein stability.

Osteosintesis percutánea anterior en las fracturas diafisarias del húmero / Minimally invasive anterior plate osteosynthesis in humeral shaft fractures

Introducción: Existe controversia en el método ideal de tratamiento de las fracturas del húmero, aunque la reducción abierta y la fijación interna con placa y tornillos es la opción más confiable. El objetivo de este trabajo es describir la técnica quirúrgica, e informar sobre las complicaciones y la tasa de consolidación de la osteosíntesis mínimamente invasiva en esas fracturas. Materiales y métodos: Entre enero de 2008 y diciembre de 2009 fueron tratados 10 pacientes con fracturas del húmero mediante reducción indirecta y fijación interna mínimamente invasiva con placa y tornillos. Resultados: Todos los pacientes fueron seguidos hasta un año después de la cirugía. Todas las fracturas se consolidaron en un promedio de 4 meses. No se produjeron lesiones neurovasculares durante el procedimiento quirúrgico. Conclusiones: La osteosíntesis percutánea utilizando la cara anterior del húmero es segura y eficaz, y es una alternativa para el tratamiento de estas fracturas

A natural and readily available crowding agent: NMR studies of proteins in hen egg white.

In vitro studies of biological macromolecules are usually performed in dilute, buffered solutions containing one or just a few different biological macromolecules. Under these conditions, the interactions among molecules are diffusion limited. On the contrary, in living systems, macromolecules of a given type are surrounded by many others, at very high total concentrations. In the last few years, there has been an increasing effort to study biological macromolecules directly in natural crowded environments, as in intact bacterial cells or by mimicking natural crowding by adding proteins, polysaccharides, or even synthetic polymers. Here, we propose the use of hen egg white (HEW) as a simple natural medium, with all features of the media of crowded cells, that could be used by any researcher without difficulty and inexpensively. We present a study of the stability and dynamics behavior of model proteins in HEW, chosen as a prototypical, readily accessible natural medium that can mimic cytosol. We show that two typical globular proteins, dissolved in HEW, give NMR spectra very similar to those obtained in dilute buffers, although dynamic parameters are clearly affected by the crowded medium. The thermal stability of one of these proteins, measured in a range comprising both heat and cold denaturation, is also similar to that in buffer. Our data open new possibilities to the study of proteins in natural crowded media.

Understanding cold denaturation: the case study of Yfh1.

All globular proteins undergo transitions from their native to unfolded states if exposed either to cold or to heat perturbation. While the heat-induced transition is well described for a large number of proteins, in media compatible with natural environments, the limited number of examples of cold denatured states concern proteins artificially destabilized, for instance, by the presence of denaturants, ad hoc point mutations, or both. Here, we provide a characterization of the low temperature unfolded state of Yfh1, a natural protein that undergoes cold denaturation around water freezing temperature, in the absence of any denaturant. By achieving nearly full assignment of the NMR spectrum, we show that at -1 °C, Yfh1 has all the features of an unfolded protein, although retaining some local, residual secondary structure. The effect is not uniform along the sequence and does not merely reflect the secondary structural features of the folded species. The N-terminus seems to be dynamically more flexible, although retaining some nascent helix character. Interestingly, this region is the one containing functionally important hot-spots. The ß-sheet region and the C-terminal helix are completely unfolded, although experiencing some conformational exchange, partly due to the presence of several prolines. Ours is the first step toward a full characterization of the low temperature unfolded state of a natural protein, reached without the aid of any destabilizing agent. We discuss the implications of our findings for understanding cold denatured states.