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1.
NEJM Evid ; : EVIDoa2400082, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38864749

RESUMEN

BACKGROUND: Whether intensive glucose control reduces mortality in critically ill patients remains uncertain. Patient-level meta-analyses can provide more precise estimates of treatment effects than are currently available. METHODS: We pooled individual patient data from randomized trials investigating intensive glucose control in critically ill adults. The primary outcome was in-hospital mortality. Secondary outcomes included survival to 90 days and time to live cessation of treatment with vasopressors or inotropes, mechanical ventilation, and newly commenced renal replacement. Severe hypoglycemia was a safety outcome. RESULTS: Of 38 eligible trials (n=29,537 participants), 20 (n=14,171 participants) provided individual patient data including in-hospital mortality status for 7059 and 7049 participants allocated to intensive and conventional glucose control, respectively. Of these 1930 (27.3%) and 1891 (26.8%) individuals assigned to intensive and conventional control, respectively, died (risk ratio, 1.02; 95% confidence interval [CI], 0.96 to 1.07; P=0.52; moderate certainty). There was no apparent heterogeneity of treatment effect on in-hospital mortality in any examined subgroups. Intensive glucose control increased the risk of severe hypoglycemia (risk ratio, 3.38; 95% CI, 2.99 to 3.83; P<0.0001). CONCLUSIONS: Intensive glucose control was not associated with reduced mortality risk but increased the risk of severe hypoglycemia. We did not identify a subgroup of patients in whom intensive glucose control was beneficial. (Funded by the Australian National Health and Medical Research Council and others; PROSPERO number CRD42021278869.).

2.
Artículo en Inglés | MEDLINE | ID: mdl-38878109

RESUMEN

PURPOSE: In forensic medicine, maceration is often essential for examining bone surfaces, serving purposes such as identifying cut marks, making geometric measurements, and determining the victim's age. While hot water maceration removes soft tissue effectively, it is known to cause bone surface shrinkage. This raises the question of whether this effect is permanent or if it can be partially reversed through rehydration, considering the presence of soft tissue. METHODS: Computed tomography (CT) scans were conducted on the radii of 20 paired human anatomic forearm specimens. Subsequently, the radii were extracted, macerated in 60 °C water, CT-scanned in an air environment, rehydrated, re-implanted into the forearms, and CT-scanned again. RESULTS: Maceration resulted in a mean shrinkage of 0.12 mm on the outer bone surface. This shrinkage was nearly fully recoverable for the diaphysis after rehydration and accounting for soft tissue surrounding the bone. In contrast, the epiphysis showed permanent shrinkage, likely due to the loss of small bone fragments. Analysis of the inner bone surface indicated a smaller effect, but with significant standard deviations, especially for the epiphysis, possibly related to the less well-defined nature of the inner bone surface. CONCLUSION: The epiphyseal surface of hot water-macerated bone will, on average, be approximately 0.15 mm deflated and cannot retain the original surface. On the other hand, the diaphyseal surface is less affected and can be nearly completely restored after rehydration and accounting for soft tissue surrounding the bone.

4.
Pan Afr Med J ; 47: 95, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38799192

RESUMEN

Abdominal pregnancy is a rare form of ectopic pregnancy (accounting for 1% of all ectopic pregnancies). Depending on gestational age and its location various symptoms and signs may be exhibited. This study aimed to report a case of abdominal pregnancy occurring in the Morrison Pouch with a primary presentation of right upper quadrant pain and to highlight complications that may arise in the management of abdominal pregnancy located in the Morrison Pouch. A 22-year pregnant woman at gestation of 22 weeks presented with a right upper quadrant mass and pain. Ultrasound examination revealed a live extrauterine singleton at Morrison Pouch, full blood count showed severe anemia. The patient received a blood transfusion in seven days and underwent emergency laparotomy after experiencing sudden acute internal hemorrhage but died a few hours post laparotomy due to hemorrhagic shock. Abdominal pregnancy carries a high risk of maternal hemorrhage as described in this case.


Asunto(s)
Dolor Abdominal , Laparotomía , Embarazo Abdominal , Humanos , Femenino , Embarazo , Adulto Joven , Dolor Abdominal/etiología , Laparotomía/métodos , Embarazo Abdominal/diagnóstico , Embarazo Abdominal/cirugía , Transfusión Sanguínea , Anemia/etiología , Anemia/diagnóstico , Choque Hemorrágico/etiología , Resultado Fatal , Hemorragia/etiología
5.
J Virol ; 98(6): e0052424, 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38757972

RESUMEN

Ebola virus glycoprotein (EBOV GP) is one of the most heavily O-glycosylated viral glycoproteins, yet we still lack a fundamental understanding of the structure of its large O-glycosylated mucin-like domain and to what degree the host O-glycosylation capacity influences EBOV replication. Using tandem mass spectrometry, we identified 47 O-glycosites on EBOV GP and found similar glycosylation signatures on virus-like particle- and cell lysate-derived GP. Furthermore, we performed quantitative differential O-glycoproteomics on proteins produced in wild-type HEK293 cells and cell lines ablated for the three key initiators of O-linked glycosylation, GalNAc-T1, -T2, and -T3. The data show that 12 out of the 47 O-glycosylated sites were regulated, predominantly by GalNAc-T1. Using the glycoengineered cell lines for authentic EBOV propagation, we demonstrate the importance of O-linked glycan initiation and elongation for the production of viral particles and the titers of progeny virus. The mapped O-glycan positions and structures allowed to generate molecular dynamics simulations probing the largely unknown spatial arrangements of the mucin-like domain. The data highlight targeting GALNT1 or C1GALT1C1 as a possible way to modulate O-glycan density on EBOV GP for novel vaccine designs and tailored intervention approaches.IMPORTANCEEbola virus glycoprotein acquires its extensive glycan shield in the host cell, where it is decorated with N-linked glycans and mucin-type O-linked glycans. The latter is initiated by a family of polypeptide GalNAc-transferases that have different preferences for optimal peptide substrates resulting in a spectrum of both very selective and redundant substrates for each isoform. In this work, we map the exact locations of O-glycans on Ebola virus glycoprotein and identify subsets of sites preferentially initiated by one of the three key isoforms of GalNAc-Ts, demonstrating that each enzyme contributes to the glycan shield integrity. We further show that altering host O-glycosylation capacity has detrimental effects on Ebola virus replication, with both isoform-specific initiation and elongation playing a role. The combined structural and functional data highlight glycoengineered cell lines as useful tools for investigating molecular mechanisms imposed by specific glycans and for steering the immune responses in future vaccine designs.


Asunto(s)
Ebolavirus , Polisacáridos , Replicación Viral , Ebolavirus/fisiología , Ebolavirus/metabolismo , Humanos , Células HEK293 , Glicosilación , Polisacáridos/metabolismo , Proteínas del Envoltorio Viral/metabolismo , Fiebre Hemorrágica Ebola/virología , Fiebre Hemorrágica Ebola/metabolismo , N-Acetilgalactosaminiltransferasas/metabolismo , N-Acetilgalactosaminiltransferasas/genética , Glicoproteínas/metabolismo , Polipéptido N-Acetilgalactosaminiltransferasa
6.
Children (Basel) ; 11(4)2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38671687

RESUMEN

BACKGROUND: Although effective, compressive orthotic bracing (COB) in children with pectus carinatum is still not standardized. This study has aimed to analyze current practices amongst members of the Chest Wall International Group (CWIG). METHODS: A web-based questionnaire was mailed to all CWIG members at 208 departments. It included 30 questions regarding diagnostic work-up, age for COB indication, type of COB used, daily wearing time, treatment duration, complications, and recurrence rate. RESULTS: Members from 44 departments have responded (institutional response rate 21.2%). A total of 93% consider COB as the first-line treatment for PC. A conventional COB (CC) is used in 59%, and the dynamic compression system (FMF) in 41%. The overall compliance rate is >80%. A total of 67% of responders consider COB to be indicated in patients <10 years. The actual wearing time is significantly shorter than the physician-recommended time (p < 0.01). FMF patients experience a significantly faster response than CC patients (p < 0.01). No recurrence of PC has been noted in 34%; recurrence rates of 10-30% have been noted in 61%. CONCLUSIONS: COB is the first-line treatment for PC with a high compliance rate. During puberty, the recurrence rate is high. Treatment standardization and follow-up until the end of puberty are recommended to enhance COB effectiveness.

7.
J Imaging Inform Med ; 2024 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-38483695

RESUMEN

The introduction of three-dimensional (3D) printed anatomical models has garnered interest in pre-operative planning, especially in orthopedic and trauma surgery. Identifying potential error sources and quantifying their effect on the model dimensional accuracy are crucial for the applicability and reliability of such models. In this study, twenty radii were extracted from anatomic forearm specimens and subjected to osteotomy to simulate a defined fracture of the distal radius (Colles' fracture). Various factors, including two different computed tomography (CT) technologies (energy-integrating detector (EID) and photon-counting detector (PCD)), four different CT scanners, two scan protocols (i.e., routine and high dosage), two different scan orientations, as well as two segmentation algorithms were considered to determine their effect on 3D model accuracy. Ground truth was established using 3D reconstructions of surface scans of the physical specimens. Results indicated that all investigated variables significantly impacted the 3D model accuracy (p < 0.001). However, the mean absolute deviation fell within the range of 0.03 ± 0.20 to 0.32 ± 0.23 mm, well below the 0.5 mm threshold necessary for pre-operative planning. Intra- and inter-operator variability demonstrated fair to excellent agreement for 3D model accuracy, with an intra-class correlation (ICC) of 0.43 to 0.92. This systematic investigation displayed dimensional deviations in the magnitude of sub-voxel imaging resolution for all variables. Major pitfalls included missed or overestimated bone regions during the segmentation process, necessitating additional manual editing of 3D models. In conclusion, this study demonstrates that 3D bone fracture models can be obtained with clinical routine scanners and scan protocols, utilizing a simple global segmentation threshold, thereby providing an accurate and reliable tool for pre-operative planning.

8.
3D Print Med ; 10(1): 5, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38376810

RESUMEN

BACKGROUND: Additively manufactured (AM) anatomical bone models are primarily utilized for training and preoperative planning purposes. As such, they must meet stringent requirements, with dimensional accuracy being of utmost importance. This study aimed to evaluate the precision and accuracy of anatomical bone models manufactured using three different AM technologies: digital light processing (DLP), fused deposition modeling (FDM), and PolyJetting (PJ), built in three different part orientations. Additionally, the study sought to assess surgeons' perceptions of how well these models mimic real bones in simulated osteosynthesis. METHODS: Computer-aided design (CAD) models of six human radii were generated from computed tomography (CT) imaging data. Anatomical models were then manufactured using the three aforementioned technologies and in three different part orientations. The surfaces of all models were 3D-scanned and compared with the original CAD models. Furthermore, an anatomical model of a proximal femur including a metastatic lesion was manufactured using the three technologies, followed by (mock) osteosynthesis performed by six surgeons on each type of model. The surgeons' perceptions of the quality and haptic properties of each model were assessed using a questionnaire. RESULTS: The mean dimensional deviations from the original CAD model ranged between 0.00 and 0.13 mm with maximal inaccuracies < 1 mm for all models. In surgical simulation, PJ models achieved the highest total score on a 5-point Likert scale ranging from 1 to 5 (with 1 and 5 representing the lowest and highest level of agreement, respectively), (3.74 ± 0.99) in the surgeons' perception assessment, followed by DLP (3.41 ± 0.99) and FDM (2.43 ± 1.02). Notably, FDM was perceived as unsuitable for surgical simulation, as the material melted during drilling and sawing. CONCLUSIONS: In conclusion, the choice of technology and part orientation significantly influenced the accuracy and precision of additively manufactured bone models. However, all anatomical models showed satisfying accuracies and precisions, independent of the AM technology or part orientation. The anatomical and functional performance of FDM models was rated by surgeons as poor.

9.
Int J Mol Sci ; 25(4)2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38396958

RESUMEN

Renal tumors comprise ~7% of all malignant pediatric tumors. Approximately 90% of pediatric kidney tumors comprise Wilms tumors, and the remaining 10% include clear cell sarcoma of the kidney, malignant rhabdoid tumor of the kidney, renal cell carcinoma and other rare renal tumors. Over the last 30 years, the role of cytokines and their receptors has been considerably investigated in both cancer progression and anti-cancer therapy. However, more effective immunotherapies require the cytokine profiling of each tumor type and comprehensive understanding of tumor biology. In this study, we aimed to investigate the activation of signaling pathways in response to cytokines in three pediatric kidney tumor cell lines, in WT-CLS1 and WT-3ab cells (both are Wilms tumors), and in G-401 cells (a rhabdoid kidney tumor, formerly classified as Wilms tumor). We observed that interferon-alpha (IFN-α) and interferon-gamma (IFN-γ) very strongly induced the activation of the STAT1 protein, whereas IL-6 and IFN-α activated STAT3 and IL-4 activated STAT6 in all examined tumor cell lines. STAT protein activation was examined by flow cytometry and Western blot using phospho-specific anti-STAT antibodies which recognize only activated (phosphorylated) STAT proteins. Nuclear translocation of phospho-STAT proteins upon activation with specific cytokines was furthermore confirmed by immunofluorescence. Our results also showed that both IFN-α and IFN-γ caused upregulation of major histocompatibility complex (MHC) class I proteins, however, these cytokines did not have any effect on the expression of MHC class II proteins. We also observed that pediatric kidney tumor cell lines exhibit the functional expression of an additional cytokine signaling pathway, the tumor necrosis factor (TNF)-α-mediated activation of nuclear factor kappa B (NF-κB). In summary, our data show that human pediatric renal tumor cell lines are responsive to stimulation with various human cytokines and could be used as in vitro models for profiling cytokine signaling pathways.


Asunto(s)
Neoplasias Renales , Factor de Necrosis Tumoral alfa , Niño , Humanos , Factor de Necrosis Tumoral alfa/metabolismo , Citocinas/metabolismo , Neoplasias Renales/patología , Interferón-alfa/metabolismo , Antígenos de Histocompatibilidad Clase I/metabolismo , Antígenos HLA , Línea Celular Tumoral , Factor de Transcripción STAT1/metabolismo , Riñón/metabolismo
10.
Phys Med Biol ; 69(3)2024 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-38164988

RESUMEN

Objective.The field of radiotherapy is highly marked by the lack of datasets even with the availability of public datasets. Our study uses a very limited dataset to provide insights on essential parameters needed to automatically and accurately segment individual bones on planning CT images of head and neck cancer patients.Approach.The study was conducted using 30 planning CT images of real patients acquired from 5 different cohorts. 15 cases from 4 cohorts were randomly selected as training and validation datasets while the remaining were used as test datasets. Four experimental sets were formulated to explore parameters such as background patch reduction, class-dependent augmentation and incorporation of a weight map on the loss function.Main results.Our best experimental scenario resulted in a mean Dice score of 0.93 ± 0.06 for other bones (skull, mandible, scapulae, clavicles, humeri and hyoid), 0.93 ± 0.02 for ribs and 0.88 ± 0.03 for vertebrae on 7 test cases from the same cohorts as the training datasets. We compared our proposed solution approach to a retrained nnU-Net and obtained comparable results for vertebral bones while outperforming in the correct identification of the left and right instances of ribs, scapulae, humeri and clavicles. Furthermore, we evaluated the generalization capability of our proposed model on a new cohort and the mean Dice score yielded 0.96 ± 0.10 for other bones, 0.95 ± 0.07 for ribs and 0.81 ± 0.19 for vertebrae on 8 test cases.Significance.With these insights, we are challenging the utilization of an automatic and accurate bone segmentation tool into the clinical routine of radiotherapy despite the limited training datasets.


Asunto(s)
Neoplasias de Cabeza y Cuello , Tomografía Computarizada por Rayos X , Humanos , Tomografía Computarizada por Rayos X/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Columna Vertebral , Cráneo , Procesamiento de Imagen Asistido por Computador/métodos
11.
Oxf Med Case Reports ; 2024(1): omad147, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38292164

RESUMEN

False-negative qualitative Human Chorionic Gonadotropin (hCG) result is a phenomenon in which large amounts of ß-hCG are produced by molar pregnancy, oversaturating the test's assay system and leading to false-negative results known as the 'prozone phenomenon' or the 'hook effect'. This can lead to misdiagnosis and delay in management despite high suspicious clinical and ultrasound findings. We report a case of an 18-year-old female who presented to our health facility with amenorrhea of 16 weeks, lower abdominal pain, soft and large fundal height for gestational age, and cramping with slight per-vaginal bleeding, and a negative urinary pregnancy test (UPT). Based on clinical presentation, ultrasound findings and a positive UPT after urine dilution, molar pregnancy was diagnosed. Aspiration was performed under ultrasound guidance, and follow-up was done as per MSF guidelines. HCPs need to be familiar with some rare cases for which the possibility of finding false-negative UPT is likely.

12.
Cancers (Basel) ; 16(2)2024 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-38254904

RESUMEN

The delineation of the clinical target volumes (CTVs) for radiation therapy is time-consuming, requires intensive training and shows high inter-observer variability. Supervised deep-learning methods depend heavily on consistent training data; thus, State-of-the-Art research focuses on making CTV labels more homogeneous and strictly bounding them to current standards. International consensus expert guidelines standardize CTV delineation by conditioning the extension of the clinical target volume on the surrounding anatomical structures. Training strategies that directly follow the construction rules given in the expert guidelines or the possibility of quantifying the conformance of manually drawn contours to the guidelines are still missing. Seventy-one anatomical structures that are relevant to CTV delineation in head- and neck-cancer patients, according to the expert guidelines, were segmented on 104 computed tomography scans, to assess the possibility of automating their segmentation by State-of-the-Art deep learning methods. All 71 anatomical structures were subdivided into three subsets of non-overlapping structures, and a 3D nnU-Net model with five-fold cross-validation was trained for each subset, to automatically segment the structures on planning computed tomography scans. We report the DICE, Hausdorff distance and surface DICE for 71 + 5 anatomical structures, for most of which no previous segmentation accuracies have been reported. For those structures for which prediction values have been reported, our segmentation accuracy matched or exceeded the reported values. The predictions from our models were always better than those predicted by the TotalSegmentator. The sDICE with 2 mm margin was larger than 80% for almost all the structures. Individual structures with decreased segmentation accuracy are analyzed and discussed with respect to their impact on the CTV delineation following the expert guidelines. No deviation is expected to affect the rule-based automation of the CTV delineation.

13.
J Mech Behav Biomed Mater ; 150: 106259, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38039773

RESUMEN

The response of bone tissue to mechanical load is complex and includes plastic hardening, viscosity and damage. The quantification of these effects plays a mayor role in bone research and in biomechanical clinical trials as to better understand related diseases. In this study, the damage growth in individual wet human trabeculae subjected to cyclic overloading is quantified by inverse rheological modeling. Therefore, an already published rheological material model, that includes linear elasticity, plasticity and viscosity is extended by a damage law. The model is utilized in an optimization process to identify the corresponding material parameters and damage growth in single human trabeculae under tensile load. Results show that the damage model is leading to a better fit of the test data with an average root-mean-square-error (RMSE) of 2.52 MPa compared to the non-damage model with a RMSE of 3.03 MPa. Although this improvement is not significant, the damage model qualitatively better represents the data as it accounts for the visible stiffness reduction along the load history. It returns realistic stiffness values of 11.92 GPa for the instantaneous modulus and 5.73 GPa for the long term modulus of wet trabecular human bone. Further, the growth of damage in the tissue along the load history is substantial, with values above 0.8 close to failure. The relative loss of stiffness per cycle is in good agreement with comparable literature. Inverse rheological modeling proves to be a valuable tool for quantifying complex constitutive behavior from a single mechanical measurement. The evolution of damage in the tissue can be identified continuously over the load history and separated from other effects.


Asunto(s)
Huesos , Hueso Esponjoso , Humanos , Estrés Mecánico , Elasticidad , Reología , Fenómenos Biomecánicos
14.
Crit. Care Sci ; 35(4): 345-354, Oct.-Dec. 2023.
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1528481

RESUMEN

ABSTRACT Objective: The optimal target for blood glucose concentration in critically ill patients is unclear. We will perform a systematic review and meta-analysis with aggregated and individual patient data from randomized controlled trials, comparing intensive glucose control with liberal glucose control in critically ill adults. Data sources: MEDLINE®, Embase, the Cochrane Central Register of Clinical Trials, and clinical trials registries (World Health Organization, clinical trials.gov). The authors of eligible trials will be invited to provide individual patient data. Published trial-level data from eligible trials that are not at high risk of bias will be included in an aggregated data meta-analysis if individual patient data are not available. Methods: Inclusion criteria: randomized controlled trials that recruited adult patients, targeting a blood glucose of ≤ 120mg/dL (≤ 6.6mmol/L) compared to a higher blood glucose concentration target using intravenous insulin in both groups. Excluded studies: those with an upper limit blood glucose target in the intervention group of > 120mg/dL (> 6.6mmol/L), or where intensive glucose control was only performed in the intraoperative period, and those where loss to follow-up exceeded 10% by hospital discharge. Primary endpoint: In-hospital mortality during index hospital admission. Secondary endpoints: mortality and survival at other timepoints, duration of invasive mechanical ventilation, vasoactive agents, and renal replacement therapy. A random effect Bayesian meta-analysis and hierarchical Bayesian models for individual patient data will be used. Discussion: This systematic review with aggregate and individual patient data will address the clinical question, 'what is the best blood glucose target for critically ill patients overall?' Protocol version 0.4 - 06/26/2023 PROSPERO registration: CRD42021278869


RESUMO Objetivo: Não está claro qual é a meta ideal de concentração de glicose no sangue em pacientes em estado grave. Realizaremos uma revisão sistemática e uma metanálise com dados agregados e de pacientes individuais de estudos controlados e randomizados, comparando o controle intensivo da glicose com o controle liberal da glicose em adultos em estado grave. Fontes de dados: MEDLINE®, Embase, Cochrane Central Register of Clinical Trials e registros de ensaios clínicos (Organização Mundial da Saúde, clinical trials.gov). Os autores dos estudos qualificados serão convidados a fornecer dados individuais de pacientes. Os dados publicados em nível de ensaio qualificado que não apresentem alto risco de viés serão incluídos em uma metanálise de dados agregados se os dados individuais de pacientes não estiverem disponíveis. Métodos: Critérios de inclusão: ensaios clínicos controlados e randomizados que recrutaram pacientes adultos, com meta de glicemia ≤ 120mg/dL (≤ 6,6mmol/L) comparada a uma meta de concentração de glicemia mais alta com insulina intravenosa em ambos os grupos. Estudos excluídos: aqueles com meta de glicemia no limite superior no grupo de intervenção > 120mg/dL (> 6,6mmol/L), ou em que o controle intensivo de glicose foi realizado apenas no período intraoperatório, e aqueles em que a perda de seguimento excedeu 10% até a alta hospitalar. Desfecho primário: Mortalidade intra-hospitalar durante a admissão hospitalar. Desfechos secundários: Mortalidade e sobrevida em outros momentos, duração da ventilação mecânica invasiva, agentes vasoativos e terapia de substituição renal. Utilizaremos metanálise bayesiana de efeito randômico e modelos bayesianos hierárquicos para dados individuais de pacientes. Discussão: Essa revisão sistemática com dados agregados e de pacientes individuais abordará a questão clínica: Qual é a melhor meta de glicose no sangue de pacientes graves em geral? Protocolo versão 0.4 - 26/06/2023 Registro PROSPERO: CRD42021278869

15.
J Med Chem ; 66(20): 14315-14334, 2023 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-37793071

RESUMEN

Siglec-7 regulates immune cell activity and is a promising target for immunomodulation. Here, we report the discovery of novel sialic acid derivatives binding to Siglec-7. Synthesis and affinity measurements are complemented by high-quality models of sialoside-Siglec-7 complexes based on molecular dynamics (MD) simulations on the microsecond time scale. We provide details for the predicted binding modes for the new ligands, e.g., that an extension of the carbon backbone leads to a different molecular interaction pattern with the receptor and the nearby water structure than found for known Siglec-7 ligands. Further on, we uncover some shortcomings of the GLYCAM06 and GAFF2 force fields when used for the simulation of sialoside-based glycomimetics. Our results open new opportunities for the rational design of Siglec-7 inhibitors. In addition, we provide strategies on how to use and visualize MD simulations to describe and investigate sialoside-Siglec complexes in general.


Asunto(s)
Ácido N-Acetilneuramínico , Lectinas Similares a la Inmunoglobulina de Unión a Ácido Siálico , Proteínas Portadoras , Ligandos
16.
Nature ; 624(7990): 201-206, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37794193

RESUMEN

Coronavirus spike proteins mediate receptor binding and membrane fusion, making them prime targets for neutralizing antibodies. In the cases of severe acute respiratory syndrome coronavirus, severe acute respiratory syndrome coronavirus 2 and Middle East respiratory syndrome coronavirus, spike proteins transition freely between open and closed conformations to balance host cell attachment and immune evasion1-5. Spike opening exposes domain S1B, allowing it to bind to proteinaceous receptors6,7, and is also thought to enable protein refolding during membrane fusion4,5. However, with a single exception, the pre-fusion spike proteins of all other coronaviruses studied so far have been observed exclusively in the closed state. This raises the possibility of regulation, with spike proteins more commonly transitioning to open states in response to specific cues, rather than spontaneously. Here, using cryogenic electron microscopy and molecular dynamics simulations, we show that the spike protein of the common cold human coronavirus HKU1 undergoes local and long-range conformational changes after binding a sialoglycan-based primary receptor to domain S1A. This binding triggers the transition of S1B domains to the open state through allosteric interdomain crosstalk. Our findings provide detailed insight into coronavirus attachment, with possibilities of dual receptor usage and priming of entry as a means of immune escape.


Asunto(s)
Betacoronavirus , Polisacáridos , Ácidos Siálicos , Glicoproteína de la Espiga del Coronavirus , Humanos , Regulación Alostérica , Betacoronavirus/química , Betacoronavirus/ultraestructura , Resfriado Común/virología , Microscopía por Crioelectrón , Simulación de Dinámica Molecular , Polisacáridos/química , Polisacáridos/metabolismo , Unión Proteica , Conformación Proteica , Ácidos Siálicos/química , Ácidos Siálicos/metabolismo , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/metabolismo , Glicoproteína de la Espiga del Coronavirus/ultraestructura , Evasión Inmune
17.
Children (Basel) ; 10(10)2023 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-37892259

RESUMEN

Objective: Bladder lesions like urothelial carcinoma are rare in the first two decades of life. A biopsy of the bladder or urinary cytological examination is seldom required. Gross painless hematuria is the most relevant clinical syndrome. Methods: A retrospective analysis of surgical pathology records collected between 1984 and 2014 at our institution was performed in a search for cases of urothelial neoplasms originating within the urinary bladder in pediatric patients. Diagnoses were confirmed based on pathologic examination using the 2004 World Health Organization (WHO) classification system. We selected keywords such as bladder neoplasia, bladder lesion, urothelial neoplasia, rhabdomyosarcoma, and children. In addition, we describe clinical presentation and diagnostic procedures as well as treatment and follow-up of two patients. A review of the literature was performed to analyze recommendations concerning diagnostic staging, treatment, and follow-up examinations as well as surveillance of urothelial tumors in the pediatric population. Results: Screening the pathology database of the Institute of Medical Genetics and Pathology of the University Hospital Basel between 1988 and 2014 yielded 287 samples involving the urinary bladder, 110 autopsies, 135 biopsies, and 42 cytology specimens. Of these, most samples originated from malformations and inflammation. Only five were tumors: two were urothelial tumors and three were rhabdomyosarcomas. The majority of specimens comprised resections of the diverticula or distal ureter. Our case reports include two patients with a urothelial tumor. Among the urothelial tumors, one was a papillary urothelial neoplasm of low malignant potential (PUNLMP). Painless hematuria was the directing clinical symptom. The tumor was investigated by FISH, and a 9p21 deletion was found. The second tumor-like lesion was a fibroepithelial polyp arising from the bladder neck. Conclusions: Bladder tumors in children are rare and mostly consist of urothelial and mesenchymal neoplasms. Rhabdomyosarcoma is the most common malignant bladder tumor in childhood. Similar to adult urothelial neoplasms, the loss of 9p21 is also implicated in urothelial neoplasms in childhood. Despite an increasing number of case reports and small series published within the last 2 decades, general treatment protocols including recommendations for staging, tumor markers, and follow-up examinations are still not yet available for this tumor entity in the pediatric population.

18.
Transl Pediatr ; 12(8): 1450-1453, 2023 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-37692546
19.
20.
Nat Commun ; 14(1): 4156, 2023 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-37438393

RESUMEN

The Amazon River accounts for 20% of global freshwater runoff and supplies vital trace metals to the Atlantic Ocean. Suspended particles within its plume are thought to partially dissolve, constituting a large potential source of metals, which is, however, not well constrained. Here we used combined neodymium (Nd) and hafnium (Hf) isotopes to disprove the release of Nd and Hf from particles as the cause of the observed dissolved concentration increases and isotopic variability across the plume. Instead, the changes reflect admixture of nearby Pará River freshwater with exceptionally high dissolved Nd and Hf concentrations contributing 45-100% of the riverine fraction to the southern and outer estuary. This result led us to develop an empirical relationship between riverine Nd concentration and pH to revise the global dissolved riverine Nd flux, which accordingly is at least three times higher than commonly used estimates. Future work should focus on contributions of low-pH rivers to global metal fluxes.

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