How to avoid baseplate failure: the effect of compression and reverse shoulder arthroplasty baseplate design on implant stability.

BACKGROUND: Failure to achieve fixation of the glenoid baseplate will lead to clinical failure. The fixation of the baseplate to the scapula must be able to withstand sufficient shear forces to allow bony ingrowth. The importance of compression to neutralize the forces at the baseplate-bone interface has been assumed to be critical in limiting excessive micromotion. The purpose of this study is to determine the effect of compression on implant stability with different baseplate designs. METHODS: Various baseplate designs (1-piece monolithic central screw [1P], 2-piece locking central screw [2PL], and 2-piece nonlocking center screw [2PNL]) were investigated at 3 different compressive forces (high [810 N], medium [640 N], and low [530 N]). Synthetic bone cylinders were instrumented, and peripheral screws were used in all models. The combination of 1 locking and 3 nonlocking peripheral screw fixation was selected as worst-case scenario. Dynamic testing protocol followed the ASTM F2028-17 standard. The baseplate micromotion at high compression was compared to low compression. Additionally, the baseplate micromotion for each design was compared at baseline (first 50 cycles) and at 10,000 cycles for the 3 different compressive forces where motion above 150 µm was defined as failure. RESULTS: Baseplate micromotion was found to negatively correlate with compression (rpb = -0.83, P < .0001). At baseline, all baseplate designs were considered stable, regardless of compression. With high compression, average micromotion at the glenoid baseplate-bone interface remained below the 150-µm threshold for all baseplate designs at 10,000 cycles (1P: 50 ± 10 µm; 2PL: 78 ± 32 µm; 2PNL: 79 ± 8 µm; P = .060). With medium compression, average micromotion at 10,000 cycles for all 3 designs remained below the 150-µm threshold (1P: 88 ± 22 µm; 2PL: 132 ± 26 µm; 2PNL: 107 ± 39 µm). The 2PL design had the highest amount of micromotion (P = .013). With low compression, both 2-piece designs had an average micromotion above the 150-µm threshold whereas the 1-piece design did not (1P: 133 ± 35 µm; 2PL: 183 ± 21 µm; 2PNL: 166 ± 39 µm). The 2PL design had significantly higher micromotion when compared to 1P design (P = .041). DISCUSSION: The stability of a central screw baseplate correlates with the amount of compression obtained and is affected by implant design. For the same amount of compression, more micromotion is observed in a 2-piece design than a 1-piece design.

Glenoid-based reference system to differentiate shoulder pathologies on plain radiographs.

BACKGROUND: Shoulder radiographs are used for evaluation and the planning of treatment of various pathologies. Making a diagnosis of these pathologies on plain radiographs occurs by recognizing the relationship of the humeral head on the registry of the glenoid. Quantification of these changes in registry does not currently exist. We hypothesize that a geometric relationship of the humeral head and the glenoid exists that is defined on an anteroposterior Grashey view radiograph by the relationship of the best-fit circle of the humeral head relative to the best-fit circle of the glenoid such that relative measurements will define the normal shoulder and the pathologic shoulder. METHODS: One hundred fifty-six shoulders were included: 53 normal shoulders, 51 with primary glenohumeral osteoarthritis (GHOA), and 52 with cuff tear arthropathy (CTA). Humeral head best-fit circle was used to define the circle of the humeral head (cHH). A glenoid best-fit circle (cG) was defined by the following rules: (1) best fit of the glenoid articular surface and (2) was limited by the acromion such that either (a) it reaches maximal interaction with the inferior surface of the acromion or (b) the perimeter of the circle is at the lateralmost point of the acromion. The relationship between cHH and cG is defined by measurement of cHH in horizontal and vertical planes relative to the glenoid circle reference. The horizontal displacement angle (HDA) measures the horizontal position of cHH relative to cG, representing the degree of medialization toward the glenoid. The vertical displacement angle (VDA) measures the vertical position of cHH relative to cG, representing the degree of superiorization toward the acromion. Angles were compared by diagnosis and sex. RESULTS: The mean HDA was 61.0° (95% confidence interval [CI] 60.3°-61.7°) in normal shoulders, 79.9° (95% CI 76.9°-82.9°) in GHOA, and 63.4° (95% CI 61.7°-65.1°) in CTA (P < .001). The mean VDA was 43.1° (95% CI 42.2°-44.0°) in normal shoulders, 40.9° (95% CI 39.9°-42.0°) in GHOA, and 59.7° (95% CI 57.6°-61.7°) in CTA (P < .001). Interobserver reliability was 0.991 (95% CI 0.94-1.0) and intraobserver reliability was 0.998 (95% CI 0.99-1.0). The geometric relationship of cHH to the glenoid circle reference was plotted for each group. CONCLUSION: A geometric relationship exists of the humeral head in reference to the glenoid circle. Together, the HDA and the VDA distinguish between a normal shoulder and those with GHOA or CTA. This suggests that this novel methodology may provide a preoperative planning tool that is easily accessible.

Manejo odontológico de pacientes con el síndrome de Ehlers-Danlos: revisión narrativa / Dental management in patients with Ehlers-Danlos syndrome: a narrative review

El síndrome de Ehlers-Danlos es una enfermedad heredita- ria, producida por mutaciones cromosómicas que pueden llegar a tener un comportamiento autosómico dominante, recesivo o ligado al cromosoma X. Se caracteriza por defectos en las enzi- mas encargadas de la estructura y síntesis de colágeno. En vista de los 20 tipos de colágeno que existen, este síndrome es extre- madamente heterogéneo tanto en su presentación clínica como en su progresión y evolución. Dentro de los signos y síntomas habituales encontramos la hiperlaxitud articular, hiperelastici- dad de la piel e hiperequimosis de los vasos sanguíneos. Con relación a las complicaciones que pueden presentar es- tos pacientes, encontramos dislocaciones articulares, fragilidad en la piel, dolor articular, ruptura de grandes vasos sanguíneos, dificultad en la cicatrización y, en consecuencia, mayor inci- dencia de procesos infecciosos y de cicatrices poco estéticas. Presenta una incidencia de 1 caso cada 2.500-5.000 na- cidos vivos. Por ello, es fundamental que el odontólogo se encuentre familiarizado con el manejo médico-dental de estos pacientes, a fin de estar preparado para brindarles un trata- miento adecuado y responder ante las posibles complicacio- nes que se pueden presentar. En esta revisión se emplearon resultados extraídos manual- mente de artículos, indexados en las bases de datos PUBMED y EBSCO, que respondían a la búsqueda de los términos Ehlers-Danlos syndrome, dental management y oral surgery. El objetivo fue describir el manejo médico-odontológico del paciente con síndrome de Ehlers-Danlos hasta la fecha (AU)

Ehlers-Danlos syndrome is a hereditary disease, produced by chromosomal mutations that can have an autosomal behavior, which can be dominant, recessive or X-linked. It is characterized by defects in the enzymes responsible for the structure and syn- thesis of collagen. In view of the 20 existent types of collagen, this syndrome is extremely heterogeneous in its clinical presentation, as well as in its progression and evolution. Within the usual signs and symptoms, we find joint hyperlaxity, skin hyperelasticity and hyper-ecchymosis of the blood vessels. Regarding the complications that these patients can pres- ent, we find joint dislocations, skin fragility, joint pain, rupture of large blood vessels, difficulty in healing and, consequently, a higher incidence of infectious processes and unsightly scars. It presents an incidence of 1 case every 2.500-5.000 live births. Therefore, it is essential that the dentist is familiar with the medical-dental management of these patients, in order to be prepared to provide them with adequate treatment and re- spond to possible complications that may arise. In this review, results were manually extracted from ar- ticles, indexed in the PUBMED and EBSCO databases, that respond to the search for the terms Ehlers-Danlos syndrome, dental management and oral surgery. The aim was describing the medical-dental management of patients with Ehlers-Dan- los syndrome to date (AU)

Effectiveness and safety of caplacizumab in acquired thrombotic thrombocytopenic purpura: health technology assessment and classification according to the methodology established in Colombia.

OBJECTIVES: Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare hematological disease whose clinical management includes caplacizumab along with plasma exchange and immunosuppression, according to international guidelines. Caplacizumab has been available in Colombia since 2022. This study seeks to determine the therapeutic classification of caplacizumab according to the methodology of the Instituto de Evaluación Tecnológica en Salud. METHODS: The classification was carried out through a deliberative process following the modified Delphi technique, with a panel of experts, made up of four hemato-oncologists, a pharmaceutical chemist, and a patient. The results of effectiveness and safety obtained through a systematic review, therapeutic thresholds (clinical significance), and degree of acceptability (willingness to use the technology) were used for the classification. RESULTS: Fourteen effectiveness and safety outcomes were submitted for the classification process. Caplacizumab showed clinical significance for some effectiveness outcomes, was not considered inferior in terms of safety, and displayed acceptability of use. Through consensus, the panel determined that caplacizumab plus the standard regimen is superior to the standard regimen in terms of treatment response and composite outcome, and no different for the other effectiveness and safety outcomes. Likewise, in overall terms, the panel determined that caplacizumab together with the standard regimen is superior to the standard regimen. CONCLUSION: Treatment with caplacizumab together with the standard regimen was considered superior to the standard regimen for the treatment of patients with aTTP, as it showed clinically significant benefits in critical outcomes for decision making, and a safety profile no different to its comparator.

Manejo odontológico de pacientes con el síndrome de Ehlers-Danlos. Revisión narrativa / Dental management in patients with Ehlers-Danlos syndrome. Narrative review

Resumen El síndrome de Ehlers-Danlos es una enfermedad hereditaria, producida por mutaciones cromosómicas que pueden llegar a tener un comportamiento autosómico dominante, recesivo o ligado al cromosoma X. Se caracteriza por defectos en las enzimas encargadas de la estructura y síntesis de colágeno. En vista de los 20 tipos de colágeno que existen, este síndrome es extremadamente heterogéneo tanto en su presentación clínica como en su progresión y evolución. Dentro de los signos y síntomas habituales encontramos la hiperlaxitud articular, hiperelasticidad de la piel e hiperequimosis de los vasos sanguíneos. Con relación a las complicaciones que pueden presentar estos pacientes, encontramos dislocaciones articulares, fragilidad en la piel, dolor articular, ruptura de grandes vasos sanguíneos, dificultad en la cicatrización y, en consecuencia, mayor incidencia de procesos infecciosos y de cicatrices poco estéticas. Presenta una incidencia de 1 caso cada 2.500-5.000 nacidos vivos. Por ello, es fundamental que el odontólogo se encuentre familiarizado con el manejo médico-dental de estos pacientes, a fin de estar preparado para brindarles un tratamiento adecuado y responder ante las posibles complicaciones que se pueden presentar. En esta revisión se emplearon resultados extraídos manualmente de artículos, indexados en las bases de datos PUBMED y EBSCO, que respondían a la búsqueda de los términos Ehlers-Danlos syndrome, dental management y oral surgery. El objetivo fue describir el manejo médico-odontológico del paciente con síndrome de Ehlers-Danlos hasta la fecha.

Abstract Ehlers-Danlos syndrome is a hereditary disease, produced by chromosomal mutations that can have an autosomal behavior, which can be dominant, recessive or X-linked. It is characterized by defects in the enzymes responsible for the structure and synthesis of collagen. In view of the 20 existent types of collagen, this syndrome is extremely heterogeneous in its clinical presentation, as well as in its progression and evolution. Within the usual signs and symptoms, we find joint hyperlaxity, skin hyperelasticity and hyper-ecchymosis of the blood vessels. Regarding the complications that these patients can present, we find joint dislocations, skin fragility, joint pain, rupture of large blood vessels, difficulty in healing and, consequently, a higher incidence of infectious processes and unsightly scars. It presents an incidence of 1 case every 2.500-5.000 live births. Therefore, it is essential that the dentist is familiar with the medical-dental management of these patients, in order to be prepared to provide them with adequate treatment and respond to possible complications that may arise. In this review, results were manually extracted from articles, indexed in the PUBMED and EBSCO databases, that respond to the search for the terms Ehlers-Danlos syndrome, dental management and oral surgery. The aim was describing the medical-dental management of patients with Ehlers-Danlos syndrome to date.

Solitary plasmacytoma of the sacrum treated with microwave ablation in conjunction with high dose of dexamethasone: A case report and review of the literature.

Background: Plasma cell neoplasms are characterized by the neoplastic proliferation of a single clone of plasma cells. Solitary plasmacytomas most often occur in bone, but they can also be found in soft tissues. Case Description: A 53-year-old male presented with localized sacral pain and urinary incontinence. His radiographic studies showed a solitary sacral plasmacytoma (i.e., involving the bone). He was successfully managed with high-dose dexamethasone and microwave ablation (MWA). Conclusion: Plasmacytomas of bone can be occasionally successfully managed with MWA, adjuvant cytoreduction therapy, and high doses of dexamethasone.

[Temporomandibular manifestation in patients with Ehlers-Danlos syndrome: a systematic review]. / Manifestaciones temporomandibulares en pacientes con síndrome de Ehlers-Danlos: una revisión sistemática.

Introduction: Ehlers-Danlos Syndrome (EDS) consists of a group of diseases that imply a disorder among individuals connective tissue due to an altered collagen production. Fibrocartilaginous structures, support ligaments, disc and retrodiscal from the temporomandibular joint are composed primarily of collagen. Objective: Identify TMJ manifestations in patients with different types of EDS. Materials and Methods: a systematic review of the literature was performed on PubMed, Scopus and Web of Science databases. Observational studies and case series reports published either in spanish or panish were included up until January 2023. Results: 12 articles met the inclusion criterial. The prevalence of temporomandibular disorders varies from 26.6% to 100%, being EDSh the most reported subtype, whereas disc displacement with or without reduction and joint hypermobility were the most reported joint disorders. Conclusion: Temporomandibular pathologies are common in patients with EDS, especially in those with the EDSh subtype.

Peptides DLL37-1 and LL37-1, an alternative to inhibit biofilm formation in clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis.

Staphylococcus aureus and Staphylococcus epidermidis have microbial surface components recognizing adhesive matrix molecules (MSCRAMM) adhesion proteins that enhance their biofilm formation ability, as well as virulence factors that influence morbidity and mortality in hospital settings. In this work, four peptides analogous of the peptide LL-37 that were evaluated to inhibit biofilm formation and its action potential on the expression of MSCRAMM proteins in clinical isolates through different tests, such as crystal violet, PCR and qPCR. In total, 96.8% of S. aureus were strong in biofilm formation in contrast to 48.4% of S. epidermidis. sdrG and sdrF genes were present in 100% of S. epidermidis strains and in all isolates. In S. aureus, specific genes that code for MSCRAMM proteins were detected: clfA (89%), clFB, sdrC and fnBA (94%). The peptides did not show hemolytic or cytotoxic activity. In this study, it was evidenced that of the peptides DLL37-1 at a 5 µM concentration was an efficacious antimicrobial agent and depicted greater biofilm inhibition in both bacterial species. Exhibiting a significant inhibition rate in S. aureus, this peptide caused a negative regulation in the expression of the genes clfA and sdrC, showed greater biological activity.

Juvenile angiolipoma in the subtemporal region, zygomatic, and pterygomaxillary fossa treated by microwave ablation - A case study and literature review.

Background: Angiolipomas are benign mesenchymal tumors that infrequently affect the head-and-neck region and can appear with infiltrating and non-infiltrating forms. Surgical excision is the treatment of choice; however, there are other alternatives to manage this condition whose consideration is quite useful to evaluate per each particular case. Case Description: An 11-year-old girl was diagnosed with non-infiltrating angiolipoma in the subtemporal region, the zygomatic, and pterygomaxillary fossa; she had a history of having undergone surgery on two previous occasions with a failed resection attempt due to the high vascularization of the injury and significant transoperative bleeding. The condition was managed with minimally invasive techniques through microwave ablation, requiring two sessions, achieving very satisfactory results both esthetically and in the final size of the lesion. Conclusion: The microwave ablation technique may turn out to be a very useful tool for the management of lesions with high vascularization such as angiolipoma. This technique offers a new possibility for initial management, both independent of and complementary to other management techniques for other lesions at the base of the skull and/or facial massif regions.

Teaching an old 'doc' new tricks for algal biotechnology: Strategic filter use enables multi-scale fluorescent protein signal detection.

Fluorescent proteins (FPs) are powerful reporters with a broad range of applications in gene expression and subcellular localization. High-throughput screening is often required to identify individual transformed cell lines in organisms that favor non-homologous-end-joining integration of transgenes into genomes, like in the model green microalga Chlamydomonas reinhardtii. Strategic transgene design, including genetic fusion of transgenes to FPs, and strain domestication have aided engineering efforts in this host but have not removed the need for screening large numbers of transformants to identify those with robust transgene expression levels. FPs facilitate transformant screening by providing a visual signal indicating transgene expression. However, limited combinations of FPs have been described in alga and inherent background fluorescence from cell pigments can hinder FP detection efforts depending on available infrastructure. Here, an updated set of algal nuclear genome-domesticated plasmid parts for seven FPs and six epitope tags were generated and tested in C. reinhardtii. Strategic filter selection was found to enable detection of up to five independent FPs signals from cyan to far-red separately from inherent chlorophyll fluorescence in live algae at the agar plate-level and also in protein electrophoresis gels. This work presents technical advances for algal engineering that can assist reporter detection efforts in other photosynthetic host cells or organisms with inherent background fluorescence.

Identifying areas of screw fixation in glenoids with severe bone loss in shoulder arthroplasty.

BACKGROUND: Severe glenoid bone loss (SGBL) poses significant technical challenges. Adequate fixation of glenoid implants may require the use of alternative screw placement. Although bone volumes for the spine and lateral pillars have previously been defined, insufficient evidence exists regarding the distribution of screw placement for fixation in such regions for cases with SGBL. The purpose of this study is to evaluate the variability of screw placement. We hypothesize that determining this variability and establishing common patterns of glenoid bone loss will allow for recommendations for preoperative planning, and implant design and selection. METHODS: An internal registry of 2 high-volume shoulder and elbow surgeons was queried, and 65 three-dimensional scapulae models exhibiting SGBL were identified. A fellowship-trained shoulder and elbow surgeon simulated the placement of two 3.5 mm × 30 mm screws, one in the scapular spine (CS) bone volume and one in the inferior column (IS) bone volume. Three orthogonal reference planes were created using anatomic reference points: the scapula trigonum, estimated glenoid center, and inferior pole. Screw positions were mapped, and deviations from the reference planes were calculated. Mutual positions of the IS to CS were also computed. Intraobserver reliability was assessed using 10 randomly selected samples. Median and 25th and 75th percentiles were reported for screw orientation distributions. Means and standard deviations were reported for screw head positions. RESULTS: We demonstrated excellent intraobserver reliability (intraclass correlation coefficients, 0.90-0.98). Fifty percent of CS were oriented 10° ± 5° of retroversion from the scapula plane, with 5° ± 5° of inclination. For IS, 50% were positioned 0° ± 4° from the scapula plane, with -33° ± 7° of inclination. The relationship of the IS with the CS was medial and posterior in 49% of cases, lateral and posterior in 45%, and lateral and anterior in 6% of cases. On average, the distance between the CS and IS heads was 25 mm ± 4 mm. DISCUSSION: For SGBL, adequate fixation of glenoid implants can be achieved by placing screws in the spine and lateral columns, with excellent reproducibility. Future implant designs should accommodate CS positioned -16° to -5° from the scapula plane, with 0° to 12° of inclination, and IS positioned -6° to 4° from the scapula plane, with -40° to -25° of inclination. Moreover, mutual screw positions suggested bone loss distributions anteriorly and inferiorly. Future implant designs should consider the potential benefits of augmentation to accommodate interscrew distances of 21-29 mm and anatomic locations of the IS relative to the CS.

Locating Ships Using Time Reversal and Matrix Pencil Method by Their Underwater Acoustic Signals.

This paper presents a technique, based on the matrix pencil method (MPM), for the compression of underwater acoustic signals produced by boat engines. The compressed signal, represented by its complex resonance expansion, is intended to be sent over a low-bit-rate wireless communication channel. We demonstrate that the method can provide data compression greater than 60%, ensuring a correlation greater than 93% between the reconstructed and the original signal, at a sampling frequency of 2.2 kHz. Once the signal was reconstituted, a localization process was carried out with the time reversal method (TR) using information from four different sensors in a simulation environment. This process sought to achieve the identification of the position of the ship using only passive sensors, considering two different sensor arrangements.

Recomendaciones bioéticas para la pandemia. Una perspectiva personalista / Bioethical recommendations for the pandemic. a personalistic perspective / Recomendações bioéticas para a pandemia. uma perspectiva personalista

Resumen La emergencia sanitaria por la pandemia del covid-19 puso en evidencia limitaciones en los sistemas de salud a nivel mundial, lo que hizo necesario un marco bioético que brinde herramientas para orientar la toma de decisiones de los profesionales de la salud ante la escasez de recursos sanitarios. Modelos bioéticos como el principialismo, el utilitarismo y la bioética centrada en la persona buscan enfocar las decisiones clínicas con base en el respeto de los derechos y la dignidad de las personas, a fin de salvaguardar la práctica médica. La bioética centrada en la persona brinda un enfoque dirigido hacia el respeto de su dignidad en situaciones de urgencia sanitaria, para evitar dar un sentido material al hombre. Se requieren criterios de decisión para afrontar los conflictos bioéticos presentes en la práctica clínica, que reduzcan la carga legal, emocional y ética de la toma de decisiones en situaciones de pandemia.

Abstract The health emergency due to the COVID-19 pandemic revealed limitations in health systems worldwide, making it necessary to establish a bioethical framework that provides tools to drive health professionals' decision-making amid scarce health resources. Bioethical models such as principlism, utilitarianism, and personalism seek to focus clinical decisions on respect for people's rights and dignity, thus protecting the medical practice. Personalism provides a person-centered approach to respect for human dignity during health emergencies to avoid giving material meaning to the individual. Decision criteria are required to face bioethical conflicts in clinical practice, reducing the legal, emotional, and ethical burden of decision-making in pandemic situations.

Resumo A emergência sanitária devido à pandemia ocasionada pela covid-19 colocou em evidência limitações nos sistemas de saúde de todo o mundo. Isso levou à necessidade de um referencial bioético que ofereça ferramentas para orientar a tomada de decisões dos profissionais da saúde ante a escassez de recursos sanitários. Modelos bioéticos como o principialismo, o utilitarismo e a bioética centralizada na pessoa procuram enfocar as decisões clínicas com base no respeito dos direitos humanos e da dignidade das pessoas, preservando a prática médica. A bioética centralizada na pessoa oferece uma abordagem dirigida ao respeito a sua dignidade em situações de emergência sanitária, para evitar dar um sentido material ao homem. São exigidos critérios de decisão para enfrentar os conflitos bioéticos presentes na prática clínica que reduzam a carga legal, emocional e ética da tomada de decisões em contextos de pandemia.

Gene Delivery Technologies with Applications in Microalgal Genetic Engineering.

Microalgae and cyanobacteria are photosynthetic microbes that can be grown with the simple inputs of water, carbon dioxide, (sun)light, and trace elements. Their engineering holds the promise of tailored bio-molecule production using sustainable, environmentally friendly waste carbon inputs. Although algal engineering examples are beginning to show maturity, severe limitations remain in the transformation of multigene expression cassettes into model species and DNA delivery into non-model hosts. This review highlights common and emerging DNA delivery methods used for other organisms that may find future applications in algal engineering.

The Human Digestive Tract Is Capable of Degrading Gluten from Birth.

The human gastrointestinal system has the capacity to metabolize dietary gluten. The capacity to degrade gliadin-derived peptide is present in humans from birth and increases during the first stages of life (up to 6-12 months of age). Fecal samples from 151 new-born and adult non-celiac disease (NCD) volunteers were collected, and glutenase and glianidase activities were evaluated. The capacity of total fecal proteins to metabolize 33-mer, 19-mer, and 13-mer gliadin peptides was also evaluated by high-performance liquid chromatography (HPLC). Feces from new-borns (meconium) showed glutenase and gliadinase activities, and peptidase activity against all three gliadin peptides. Maximal gluten degradative activity was observed in fecal samples from the youngest volunteers (0-12 months old). After the age of nine months, the gluten digestive capacity of gastrointestinal tract decreases and, from ±8 years old, individuals lose the ability to completely degrade toxic peptides. The gastrointestinal proteases involved in gluten digestion: elastase 2A, elastase 3B, and carboxipeptidase A1 are present from earlier stages of life. The human digestive tract contains the proteins capable of metabolizing gluten from birth, even before starting gluten intake. Humans are born with the ability to digest gluten and to completely degrade the potentially toxic gliadin-derived peptides (33-, 19-, and 13-mer).

Influence of reverse total shoulder arthroplasty baseplate design on torque and compression relationship.

BACKGROUND: A linear relationship between baseplate insertion torque and compression force in reverse shoulder arthroplasty (RSA) baseplates with central screw design has been recently established. In this study, we evaluated 3 different baseplate designs and their influence on the torque-compression relationship. METHODS: Three different RSA baseplate designs were evaluated through biomechanical testing using a glenoid vault, bone surrogate model. A digital torque gauge was used to measure insertion torque applied to the baseplate, whereas compression data were collected continuously from a load cell. Additionally, 2 predictive models were developed to predict the compression forces of each baseplate design at varying levels of torque. RESULTS: A linear relationship was found between baseplate compression and insertion torque for all 3 baseplate designs. Both the monoblock and 2-piece locking designs achieved the goal torque of 6.8 Nm, whereas the 2-piece nonlocking design did not due to material strip-out. No significant difference in maximum compression was found between the monoblock and 2-piece locking designs. However, the 2-piece nonlocking design achieved significantly higher compression. Both predictive models were shown to adequately predict compressive forces at different torque inputs for the monoblock and 2-piece locking designs but not the 2-piece nonlocking design. CONCLUSION: The torque-compression relationship of a central screw baseplate is significantly affected by baseplate design. A 2-piece nonlocking baseplate reaches higher compression levels and risks material strip-out at lower insertional torques compared with a monoblock and 2-piece locking design. This has implications both on component design and on surgeon tactile feedback during surgery.

Relationship Between Insertion Torque and Compression Strength in the Reverse Total Shoulder Arthroplasty Baseplate.

Reverse shoulder arthroplasty is a well-established procedure, however, there is limited data in the literature regarding adequate insertion torque and the resulting compression for glenoid baseplate fixation. In this biomechanical study, we evaluated the relationship between insertion torque and baseplate compression by simultaneously measuring the insertion torque and axial compressive forces generated by two reverse shoulder arthroplasty baseplates with central screw design. Three different bone surrogates were chosen to mimic clinical scenarios where differences in compression achieved during baseplate insertion may exist due to varying bone quality. Epoxy resin sheets were combined with the bone surrogates to simulate the glenoid vault. A digital torque gauge was used to measure insertion torque applied to the baseplate, while compression data were collected continuously from a load cell. A strong positive correlation was found between baseplate compression and insertion torque. Among the lower density bone surrogates, neither baseplate design reached maximum insertion torque (6.8 Nm) due to material strip-out. This phenomenon did not occur in denser bone surrogates. Both baseplate designs experienced a significant increase in mean baseplate compression as insertion torque increased and were found to behave similar in the denser bone surrogates. The results presented here suggest that larger compressive forces can be achieved with an increase in insertion torque in denser bone surrogates, but caution must be used when trying to achieve fixation in poor-quality bone. Clinically, this could be useful preoperatively to minimize baseplate failure, and in further studies regarding baseplate design for improved initial fixation and stability. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:871-879, 2020.

Detection of carbapenemase-producing Pseudomonas aeruginosa: Evaluation of the carbapenem inactivation method (CIM) / Detección de Pseudomonas aeruginosa productoras de carbapenemasas: evaluación del método de inactivación de carbapenem

INTRODUCTION: The carbapenem inactivation method (CIM) is a cost-effective assay for detecting carbapenemases. However, its interpretation is unclear for Pseudomonas spp. We evaluate its accuracy when meropenem is changed to imipenem. METHODS: We analyzed 266 P. aeruginosa isolates. The CIM method consists of: resuspend bacterial colonies (a full 10 μ,L loop) in 400 μ,L water, in which a 10 μ,g disk of meropenem/imipenem is immersed. After 2 h of incubation (35°C), remove the disk, place it onto a Mueller-Hinton agar plate previously inoculated with Escherichia coli (ATCC 25922), and incubate at 35 ̊C between 18-24 h. Interpretation criteria (mm of inhibition zone): ≤ 19 mm, positive; ≥ 25 mm negative; 20-24 mm, undetermined. RESULTS: Imipenem improves the sensitivity and specificity of CIM when compared to meropenem (99.4% and 98.9%, vs. 91.9% and 94.7%, respectively). CONCLUSIONS: The accuracy of CIM for carbapenemase detection in P. aeruginosa is increased with the use of imipenem

INTRODUCCIÓN: El método de inactivación del carbapenem (CIM, por sus siglas en inglés) se utiliza para detectar carbapenemasas, pero su interpretación no está clara para Pseudomonas spp. Se evaluó la precisión del método utilizando imipenem en lugar de meropenem. MÉTODOS: Se estudiaron 266 aislados de P. aeruginosa. El CIM consiste en: suspender colonias bacterianas (un asa de 10 μ,l) en 400 μ,l de agua en los que se sumerge un disco de 10 μ,g de meropenem/imipenem. Tras 2 h de incubación (35°C) se saca el disco y es transferido a agar Mueller-Hinton, previamente inoculado con Escherichia coli (ATCC 25922) e incubado a 35°C entre 18-24h. Criterios de interpretación (mm halo de inhibición): ≤ 19 mm positivo; ≥ 25 mm negativo y 20-24 mm indeterminado. RESULTADOS: Imipenem mejora la sensibilidad y especificidad del CIM frente a meropenem (99,4 y 98,9% vs. 91,9 y 94,7%, respectivamente). CONCLUSIONES: La precisión del CIM para la detección de carbapenemasas en P. aeruginosa mejora al utilizar imipenem

The role of RcsA in the adaptation and survival of Escherichia coli K92.

The Rcs phosphorelay is a two-component signal transduction system that senses stressful environmental signals such as desiccation or low temperatures, which serve as natural inducers in bacteria. RcsA is an important coregulator in this system involved in some functions regulated by the Rcs system, including biofilm formation and capsule synthesis. In this sense, we previously showed that RcsA is necessary for colanic acid synthesis in Escherichia coli K92. Here, using an E. coli K92ΔrcsA mutant lacking rcsA gene we further characterize the implications of RcsA on E. coli K92 survival under osmotic and oxidative stressful conditions, and bacterial attachment and biofilm formation on both biotic and abiotic surfaces. Our results show that RcsA protects E. coli K92 against osmotic and, especially, oxidative stress at low temperatures. In addition, RcsA did not interfere in biofilm formation in any surface tested, including polystyrene, stainless steel, silicone, Teflon, aluminum and glass. By contrast, deletion of rcsA increased bacterial attachment to the caco-2 cells monolayer used as biotic surface.