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1.
Cell ; 185(26): 4999-5010.e17, 2022 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-36435179

RESUMO

CRISPR-Cas systems have been co-opted by Tn7-like transposable elements to direct RNA-guided transposition. Type V-K CRISPR-associated transposons rely on the concerted activities of the pseudonuclease Cas12k, the AAA+ ATPase TnsC, the Zn-finger protein TniQ, and the transposase TnsB. Here we present a cryo-electron microscopic structure of a target DNA-bound Cas12k-transposon recruitment complex comprised of RNA-guided Cas12k, TniQ, a polymeric TnsC filament and, unexpectedly, the ribosomal protein S15. Complex assembly, mediated by a network of interactions involving the guide RNA, TniQ, and S15, results in R-loop completion. TniQ contacts two TnsC protomers at the Cas12k-proximal filament end, likely nucleating its polymerization. Transposition activity assays corroborate our structural findings, implying that S15 is a bona fide component of the type V crRNA-guided transposon machinery. Altogether, our work uncovers key mechanistic aspects underpinning RNA-mediated assembly of CRISPR-associated transposons to guide their development as programmable tools for site-specific insertion of large DNA payloads.


Assuntos
Proteínas Associadas a CRISPR , Elementos de DNA Transponíveis , Elementos de DNA Transponíveis/genética , Sistemas CRISPR-Cas , Transposases/genética , Proteínas de Ligação a DNA/metabolismo , RNA , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas Associadas a CRISPR/genética
2.
Nature ; 599(7885): 497-502, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34759315

RESUMO

Canonical CRISPR-Cas systems provide adaptive immunity against mobile genetic elements1. However, type I-F, I-B and V-K systems have been adopted by Tn7-like transposons to direct RNA-guided transposon insertion2-7. Type V-K CRISPR-associated transposons rely on the pseudonuclease Cas12k, the transposase TnsB, the AAA+ ATPase TnsC and the zinc-finger protein TniQ7, but the molecular mechanism of RNA-directed DNA transposition has remained elusive. Here we report cryo-electron microscopic structures of a Cas12k-guide RNA-target DNA complex and a DNA-bound, polymeric TnsC filament from the CRISPR-associated transposon system of the photosynthetic cyanobacterium Scytonema hofmanni. The Cas12k complex structure reveals an intricate guide RNA architecture and critical interactions mediating RNA-guided target DNA recognition. TnsC helical filament assembly is ATP-dependent and accompanied by structural remodelling of the bound DNA duplex. In vivo transposition assays corroborate key features of the structures, and biochemical experiments show that TniQ restricts TnsC polymerization, while TnsB interacts directly with TnsC filaments to trigger their disassembly upon ATP hydrolysis. Together, these results suggest that RNA-directed target selection by Cas12k primes TnsC polymerization and DNA remodelling, generating a recruitment platform for TnsB to catalyse site-specific transposon insertion. Insights from this work will inform the development of CRISPR-associated transposons as programmable site-specific gene insertion tools.


Assuntos
Sistemas CRISPR-Cas , Cianobactérias , Elementos de DNA Transponíveis/genética , Edição de Genes/métodos , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/ultraestrutura , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/ultraestrutura , Biopolímeros , Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Microscopia Crioeletrônica , Cianobactérias/enzimologia , Cianobactérias/genética , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , DNA Bacteriano/ultraestrutura , Modelos Moleculares , Mutagênese Insercional , Polimerização , RNA/genética , RNA/metabolismo , Especificidade por Substrato , Transposases/metabolismo , Transposases/ultraestrutura , Dedos de Zinco
3.
Cell ; 136(3): 473-84, 2009 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-19203582

RESUMO

Genomic abnormalities are often seen in tumor cells, and tetraploidization, which results from failures during cytokinesis, is presumed to be an early step in cancer formation. Here, we report a cell division control mechanism that prevents tetraploidization in human cells with perturbed chromosome segregation. First, we found that Aurora B inactivation promotes completion of cytokinesis by abscission. Chromosome bridges sustained Aurora B activity to posttelophase stages and thereby delayed abscission at stabilized intercellular canals. This was essential to suppress tetraploidization by furrow regression in a pathway further involving the phosphorylation of mitotic kinesin-like protein 1 (Mklp1). We propose that Aurora B is part of a sensor that responds to unsegregated chromatin at the cleavage site. Our study provides evidence that in human cells abscission is coordinated with the completion of chromosome segregation to protect against tetraploidization by furrow regression.


Assuntos
Segregação de Cromossomos , Citocinese , Ploidias , Proteínas Serina-Treonina Quinases/metabolismo , Aurora Quinase B , Aurora Quinases , Divisão Celular , Células HeLa , Humanos , Proteínas Associadas aos Microtúbulos/metabolismo
4.
Paediatr Anaesth ; 34(1): 86-88, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37728186

RESUMO

We report a case of aseptic cutaneous necrosis from extravasation of calcium chloride at the proximal port of a central venous catheter (CVC). A right internal jugular CVC was placed with ultrasound guidance using contemporary guidelines for size and insertion site. Catheter migration occurred concurrent with development of postoperative anasarca. Four days later, leakage of infusate with skin necrosis was noted at the insertion site. Despite initial proper positioning, catheter ports can migrate out of intravascular structures due to postprocedural subcutaneous edema. Intravascular confirmation should be performed regularly for infants with localized or generalized edema.


Assuntos
Cateterismo Venoso Central , Cateteres Venosos Centrais , Recém-Nascido , Humanos , Cateteres Venosos Centrais/efeitos adversos , Cateterismo Venoso Central/efeitos adversos , Cateteres de Demora/efeitos adversos , Edema/etiologia , Necrose , Veias Jugulares/diagnóstico por imagem
5.
J Infect Dis ; 227(5): 641-650, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36408631

RESUMO

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important prophylactic measure in kidney transplant recipients (KTRs), but the immune response is often impaired. Here, we examined the T-cell immune response against SARS-CoV-2 in 148 KTRs after 3 or 4 vaccine doses, including 35 KTRs with subsequent SARS-CoV-2 infection. The frequency of spike-specific T cells was lower in KTRs than in immunocompetent controls and was correlated with the level of spike-specific antibodies. Positive predictors for detection of vaccine-induced T cells were detection of spike-specific antibodies, heterologous immunization with messenger RNA and a vector vaccine, and longer time after transplantation. In vaccinated KTRs with subsequent SARS-CoV-2 infection, the T-cell response was greatly enhanced and was significantly higher than in vaccinated KTRs without SARS-CoV-2 infection. Overall, the data show a correlation between impaired humoral and T-cell immunity to SARS-CoV-2 vaccination and provide evidence for greater robustness of hybrid immunity in KTRs.


Assuntos
COVID-19 , Transplante de Rim , Vacinas , Humanos , SARS-CoV-2 , Vacinas contra COVID-19 , Linfócitos T , Transplantados , Anticorpos , Imunidade
6.
Chem Rev ; 121(18): 11194-11237, 2021 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-33605717

RESUMO

Fabricating a porous scaffold with high surface area has been a major strategy in the tissue engineering field. Among the many fabrication methods, electrospinning has become one of the cornerstone techniques due to its enabling the fabrication of highly porous fibrous scaffolds that are of natural or synthetic origin. Apart from the basic requirements of mechanical stability and biocompatibility, scaffolds are further expected to embody functional cues that drive cellular functions such as adhesion, spreading, proliferation, migration, and differentiation. There are abundant distinct approaches to introducing bioactive molecules to have a control over cellular functions. However, the lack of a thorough understanding of cell behavior with respect to the availability and spatial distribution of the bioactive molecules in 3D fibrous scaffolds is yet to be addressed. The rational selection of proper sets of characterization techniques would essentially impact the interpretation of the cell-scaffold interactions. In this timely Review, we summarize the most popular methods to introduce functional compounds to electrospun fibers. Thereafter, the strength and limitations of the conventional characterization methods are highlighted. Finally, the potential and applicability of emerging characterization techniques such as high-resolution/correlative microscopy approaches are further discussed.


Assuntos
Engenharia Tecidual , Alicerces Teciduais , Diferenciação Celular , Porosidade , Engenharia Tecidual/métodos
7.
Zentralbl Chir ; 148(4): 329-336, 2023 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-37562394

RESUMO

The German healthcare sector is responsible for 5.2% of the country's greenhouse gas emissions. One contributing factor is the enormous amount of waste generated daily in German hospitals, making them the fifth largest waste producer in Germany. Despite the potential for recycling, a significant portion of hospital waste is incinerated, as mandated by current regulations. This results in high levels of noxious CO2 emissions and the loss of valuable resources. The goal of this project was to demonstrate the feasibility of recycling complex, contaminated disposable surgical instruments.The study included frequently used disposable surgical instruments that could potentially be recycled as electronic waste. The instruments were wipe-disinfected and sterilised internally within the hospital. After sterilisation, the devices could be classified as electronic waste in consultation with the environmental authorities and then machine-recycled externally by a waste disposal company. Sorting machines shredded and separated the instruments into individual fractions of cables, plastics, different metals, and circuit boards, which were further processed into secondary raw materials.In the first six months (09/2022-03/2023), 239 kg of material were recycled instead of being incinerated. This resulted in a reduction of 545 kg CO2e. The metal content was estimated as 50% of the total weight; 30% were recyclable plastics, resulting in an 80% recycling rate. The ongoing recycling costs were 1.90 €/kg after deducting revenues. Thus, recycling in this model was approximately 3.9 times as expensive as incineration. A survey of the operating theatre personnel found high satisfaction with the recycling project and a minimal additional workload of less than five minutes.We demonstrated that recycling of contaminated disposable surgical instruments is possible in coordination with government authorities. This approach avoids waste incineration and leads to a reduction in CO2-equivalent emissions. However, the higher costs of recycling and the requirement for in-house decontamination pose limitations on the implementation of such projects. To address this, it is necessary for lawmakers to reconsider current regulations and involve manufacturers in recycling costs to fully exploit the enormous recycling potential.


Assuntos
Dióxido de Carbono , Eliminação de Resíduos , Humanos , Eliminação de Resíduos/métodos , Incineração/métodos , Plásticos , Alemanha
8.
Nephrol Dial Transplant ; 37(4): 673-680, 2022 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-34875087

RESUMO

BACKGROUND: The Seraph® 100 Microbind® Affinity Blood Filter is a haemoperfusion device that is licensed for the reduction of pathogens, including several viruses, in the blood. It received Emergency Use Authorization for the treatment of severe coronavirus disease 2019 (COVID-19) by the Food and Drug Administration (FDA). Several studies have shown that the blood viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) correlates with adverse outcomes and removal of the nucleocapsid of the SARS-CoV-2 virus by the Seraph® 100 has been recently demonstrated. The aim of this registry was to evaluate the safety and efficacy of Seraph® 100 treatment for COVID-19 patients. METHODS: Twelve hospitals from six countries representing two continents documented patient and treatment characteristics as well as outcome parameters without reimbursement. Additionally, mortality and safety results of the device were reported. A total of 102 treatment sessions in 82 patients were documented in the registry. Four patients were excluded from mortality analysis due to incomplete outcome data, which were available in the other 78 patients. RESULTS: Overall, a 30-day mortality rate of 46.2% in the 78 patients with complete follow-up was reported. The median treatment time was 5.00 h (4.00-13.42) and 43.1% of the treatments were performed as haemoperfusion only. Adverse events of the Seraph® 100 treatment were reported in 8.8% of the 102 treatments and represented the premature end of treatment due to circuit failure. Patients who died were treated later in their intensive care unit (ICU) stay and onset of COVID symptoms. They also had higher ferritin levels. Multivariate Cox regression revealed that delayed Seraph® 100 treatment after ICU admission (>60 h), as well as bacterial superinfection, were associated with mortality. While average predicted mortality rate according to Sequential Organ Failure Assessment (SOFA) score in ICU patients was 56.7%, the observed mortality was 50.7%. In non-ICU patients, Coronavirus Clinical Characterisation Consortium (4C) score average predicted a mortality rate of 38.0%, while the observed mortality rate was 11.1%. CONCLUSIONS: The treatment of COVID-19 patients with Seraph® 100 is well tolerated and the circuit failure rate was lower than previously reported for kidney replacement therapy (KRT) in COVID-19 patients. Mortality correlated with late initiation of Seraph treatment after ICU admission and bacterial superinfection. Compared with predicted mortality according to 4C and SOFA scores, mortality of Seraph® 100-treated patients reported in the registry was lower.


Assuntos
COVID-19 , Hemoperfusão , COVID-19/terapia , Cuidados Críticos , Humanos , Unidades de Terapia Intensiva , Sistema de Registros , SARS-CoV-2
9.
Clin Transplant ; 36(11): e14790, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35997031

RESUMO

Modification of vaccination strategies is necessary to improve the immune response to SARS-CoV-2 vaccination in kidney transplant recipients (KTRs). This multicenter observational study analyzed the effects of the third SARS-CoV-2 vaccination in previously seronegative KTRs with the focus on temporary mycophenolate mofetil (MMF) dose reduction within propensity matched KTRs. 56 out of 174 (32%) previously seronegative KTRs became seropositive after the third vaccination with only three KTRs developing neutralizing antibodies against the omicron variant. Multivariate logistic regression revealed that initial antibody levels, graft function, time after transplantation and MMF trough levels had an influence on seroconversion (P < .05). After controlling for confounders, the effect of MMF dose reduction before the third vaccination was calculated using propensity score matching. KTRs with a dose reduction of ≥33% showed a significant decrease in MMF trough levels to 1.8 (1.2-2.5) µg/ml and were more likely to seroconvert than matched controls (P = .02). Therefore, a MMF dose reduction of 33% or more before vaccination is a promising approach to improve success of SARS-CoV-2 vaccination in KTRs.


Assuntos
COVID-19 , Transplante de Rim , Humanos , Ácido Micofenólico/uso terapêutico , Vacinas contra COVID-19 , Rejeição de Enxerto , Imunossupressores/uso terapêutico , Imunossupressores/farmacologia , SARS-CoV-2 , COVID-19/prevenção & controle , Transplantados , Imunidade
10.
J Intensive Care Med ; 34(11-12): 917-923, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-28847236

RESUMO

OBJECTIVE: Nitric oxide is utilized after pediatric cardiac surgery as an off-label medication without much evidence, is expensive, and varies among centers of varying surgical volume. The objective of our study was to describe the spectrum of nitric oxide utilization and to evaluate the effect of nitric oxide utilization on outcomes among patients cared for in centers of varying surgical volume using Pediatric Health Information system. METHODS: Patients aged ≤18 years undergoing heart surgery were included (2004-2015). Multivariable mixed-effects logistic regression models were fitted to evaluate association of center volume with odds of nitric oxide utilization among patients undergoing heart operations. Centers were classified into 3 volume categories based on tertiles of number of cardiopulmonary bypass cases performed (low volume: 34 792 patients, 21 centers; medium volume: 38 362 patients, 13 centers; high volume: 30 560 patients, 7 centers). RESULTS: A total of 103 714 patients from 41 hospitals were included. Of these, 15 708 (15.1%) patients received nitric oxide after cardiac surgery. Of the patients receiving nitric oxide, only 3936 (25.1%) patients were associated with a diagnosis of pulmonary hypertension. In adjusted models, low- and medium-volume centers were associated with higher nitric oxide utilization after heart operations as compared to high-volume centers (low vs high, odds ratio [OR]: 1.48, 95% confidence interval [CI]: 1.38-1.60; medium vs high, OR: 1.33, 95% CI: 1.26-1.41). Despite higher nitric oxide utilization, the mortality was worse among patients treated in low- and medium-volume centers, as compared to high-volume centers (low vs high, OR: 1.42, 95% CI: 1.26-1.60; medium vs high, OR: 1.14, 95% CI: 1.04-1.25). CONCLUSIONS: This study demonstrates variation in nitric oxide utilization after heart operations among centers of varying surgical volume. Further, it raises questions on the benefit of nitric oxide administration after pediatric cardiac surgery.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Hospitais com Alto Volume de Atendimentos/estatística & dados numéricos , Hospitais com Baixo Volume de Atendimentos/estatística & dados numéricos , Óxido Nítrico/uso terapêutico , Uso Off-Label/estatística & dados numéricos , Pré-Escolar , Bases de Dados Factuais , Feminino , Humanos , Lactente , Recém-Nascido , Modelos Logísticos , Masculino , Período Pós-Operatório , Resultado do Tratamento , Estados Unidos
11.
J Pediatr Orthop ; 44(1): 61-62, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38078490
12.
Anesth Analg ; 127(1): 181-187, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29750690

RESUMO

BACKGROUND: Perioperative respiratory adverse events (PRAEs) account for the major cause of morbidity and mortality in children undergoing general anesthesia. In our institutional clinical practice, we suspected that African American children experienced untoward respiratory events more frequently than other racial groups. Identification of high-risk groups can guide decision making in the perioperative period, and aggressive optimization of specific care can enhance safety and improve outcomes. METHODS: Data came from a retrospective chart review for records from August 2013 to December 2013. The primary aim was to compare the incidence of PRAEs among racial groups of young children at a single institution. We also analyzed factors that are potentially associated with a higher risk of PRAEs. There were 1148 records that met the inclusion criteria. Racial identities, PRAEs, and risk factors were identified. Logistic regression analysis was performed to evaluate differences in PRAEs among racial groups controlling for confounding variables. RESULTS: Of all 1148 patients, 62 (5.4%) had a PRAE. African American children had significantly higher incidences of PRAE (26/231, 11.4%) compared to Caucasian (27/777, 3.5%; P < .001). Although the most common PRAE was laryngospasm, bronchospasm was the most common PRAE for African American children. Otolaryngology procedures were most commonly associated with PRAEs, followed by orthodontic procedures. CONCLUSIONS: In a multivariable logistic analysis, African American pediatric patients were shown to have significantly higher odds of PRAEs when compared with the Caucasian group.


Assuntos
Anestesia Geral/efeitos adversos , Negro ou Afro-Americano , Doenças Respiratórias/etnologia , População Branca , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Masculino , Período Perioperatório , Doenças Respiratórias/diagnóstico , Doenças Respiratórias/fisiopatologia , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Estados Unidos/epidemiologia
13.
Biomacromolecules ; 18(3): 695-708, 2017 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-28211679

RESUMO

The regenerative potential of bone is strongly impaired in pathological conditions, such as nonunion fractures. To support bone regeneration various scaffolds have been developed in the past, which have been functionalized with osteogenic growth factors such as bone morphogenetic proteins (BMPs). However, most of them required supra-physiological levels of these proteins leading to burst releases, thereby causing severe side effects. Site-specific, covalent coupling of BMP2 to implant materials might be an optimal strategy in order to overcome these problems. Therefore, we created a BMP-2 variant (BMP2-K3Plk) containing a noncanonical amino acid (propargyl-l-lysine) substitution introduced by genetic code expansion that allows for site-specific and covalent immobilization onto polymeric scaffold materials. To directly compare different coupling strategies, we also produced a BMP2 variant containing an additional cysteine residue (BMP2-A2C) allowing covalent coupling by thioether formation. The BMP2-K3Plk mutant was coupled to functionalized beads by a copper-catalyzed azide-alkyne cycloaddition (CuAAC) either directly or via a short biotin-PEG linker both with high specificity. After exposing the BMP-coated beads to C2C12 cells, ALP expression appeared locally restricted in close proximity to these beads, showing that both coupled BMP2 variants trigger cell differentiation. The advantage of our approach over non-site-directed immobilization techniques is the ability to produce fully defined osteogenic surfaces, allowing for lower BMP2 loads and concomitant higher bioactivities, for example, due to controlled orientation toward BMP2 receptors. Such products might provide superior bone healing capabilities with potential safety advantages as of homogeneous product outcome.


Assuntos
Proteína Morfogenética Óssea 2/genética , Proteínas Imobilizadas/química , Alicerces Teciduais/química , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Materiais Biocompatíveis/química , Proteína Morfogenética Óssea 2/química , Regeneração Óssea/fisiologia , Osso e Ossos/citologia , Osso e Ossos/metabolismo , Diferenciação Celular , Linhagem Celular Tumoral , Clonagem Molecular , Humanos , Osteogênese/fisiologia , Polímeros/química
14.
Clin Nephrol ; 88(1): 27-32, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28427496

RESUMO

BACKGROUND: Mortality of critically-ill patients with acute kidney injury (AKI) requiring renal replacement therapy (RRT) in an intensive-care setting continues to remain high. There is still uncertainty as to which factors should guide clinical judgement. METHODS: A cohort of 155 patients admitted to an intensive-care unit and necessitating RRT due to AKI were retrospectively analyzed. Demographic and clinical parameters at the time of RRT initiation were retrieved. Multi- and univariate analyses were performed to determine the impact of different risk factors on mortality. RESULTS: The most common causes of AKI were sepsis (39.3%) and cardiac events (32%). The majority of patients were treated by continuous (67.3%), the others by intermittent RRT. After 30 days, 51.0% of patients survived. Nonsurvivors were older (73 vs. 69 years), had a higher APACHEE II score (30.1 ± 5.6 vs. 26.5 ± 7.1), and were more likely to be vasopressor dependent, mechanically ventilated, or treated by continuous RRT. Multivariate analysis revealed that higher age, higher APACHEE II score, and lower serum creatinine at baseline were independent predictors for mortality, whereas histories of diabetes mellitus, arterial hypertension, coronary heart disease, or stroke were not. CONCLUSION: Critically-ill patients with AKI requiring RRT continue to have a high mortality. Age and APACHE II score showed an impact on mortality whereas traditional cardiovascular risk factors did not. Higher BUN and creatinine levels do not have a negative impact on mortality. Our findings support the current practice that RRT initiation should primarily be guided by clinical decision.
.


Assuntos
Injúria Renal Aguda/mortalidade , Unidades de Terapia Intensiva , Terapia de Substituição Renal , Injúria Renal Aguda/terapia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco
15.
Nano Lett ; 16(2): 1387-91, 2016 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-26761190

RESUMO

We report on ballistic transport over more than 28 µm in graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride. The structures are fabricated by an advanced dry van-der-Waals transfer method and exhibit carrier mobilities of up to three million cm(2)/(Vs). The ballistic nature of charge transport is probed by measuring the bend resistance in cross- and square-shaped devices. Temperature-dependent measurements furthermore prove that ballistic transport is maintained exceeding 1 µm up to 200 K.

16.
Biochemistry ; 55(4): 659-74, 2016 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-26685112

RESUMO

The four WW domains of human Nedd4-1 (neuronal precursor cell expressed developmentally downregulated gene 4-1) interact with the PPxY (PY) motifs of the human epithelial Na(+) channel (hENaC) subunits, with the third WW domain (WW3*) showing the highest affinity. We have shown previously that the α-hENaC PY motif binding interface of WW3* undergoes conformational exchange on the millisecond time scale, indicating that conformational sampling plays a role in peptide recognition. To further understand this role, the structure and dynamics of hNedd4-1 WW3* were investigated. The nuclear Overhauser effect-derived structure of apo-WW3* resembles the domain in complex with the α-hENaC peptide, although particular side chain conformations change upon peptide binding, which was further investigated by molecular dynamics simulations. Model-free analysis of the (15)N nuclear magnetic resonance spin relaxation data showed that the apo and peptide-bound states of WW3* have similar backbone picosecond to nanosecond time scale dynamics. However, apo-WW3* exhibits pronounced chemical exchange on the millisecond time scale that is quenched upon peptide binding. (1)HN and (15)N Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments at various temperatures revealed that apo-WW3* exists in an equilibrium between the natively folded peptide binding-competent state and a random coil-like denatured state. The thermodynamics of the folding equilibrium was determined by fitting a thermal denaturation profile monitored by circular dichroism spectroscopy in combination with the CPMG data, leading to the conclusion that the unfolded state is populated to ∼ 20% at 37 °C. These results show that the binding of the hNedd4-1 WW3* domain to α-hENaC is coupled to the folding equilibrium.


Assuntos
Complexos Endossomais de Distribuição Requeridos para Transporte/química , Simulação de Dinâmica Molecular , Ubiquitina-Proteína Ligases/química , Motivos de Aminoácidos , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Humanos , Ubiquitina-Proteína Ligases Nedd4 , Dobramento de Proteína , Estrutura Terciária de Proteína , Ubiquitina-Proteína Ligases/metabolismo
17.
Nephrol Dial Transplant ; 31(8): 1327-34, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26442902

RESUMO

BACKGROUND: Although citrate dialysate (CiDi) is regarded to be safe, dialysis modalities using higher dialysate volumes, like haemodiafiltration (HDF), may expose patients to higher citrate load and thus increase the risk of complications. We investigated the residual risk of CiDi compared with standard dialysate (StDi) in patients on different dialysis modalities and its effect on dialysis dose. METHODS: In a multicentre randomized crossover study, 92 dialysis patients (HDF post-dilution: n = 44, HDF pre-dilution: n = 26, haemodialysis: n = 25) were treated for 4 weeks with each dialysate (StDi and CiDi). Hypocalcaemia (ionized calcium ≤0.9 mmol/L), alkalosis (pH ≥7.55), post-treatment bicarbonate ≥32 mmol/L, pre-treatment bicarbonate ≥27 mmol/L, intra-dialytic events (IEs) and adverse events (AEs) between dialysis sessions were investigated as primary end points. The secondary objective was dialysis efficacy, i.e. dose and removal ratios of urea, creatinine, phosphate and ß-2-microglobulin. RESULTS: Post-dialysis overcorrection of bicarbonate (>32 mmol/L) was less frequent with CiDi (P = 0.008). Other predefined calcium and acid-base disturbances did not vary. There was no significant difference in IE. However, more patients developed AEs such as fatigue, muscle spasms or pain using CiDi (StDi: 41 versus CiDi: 55 patients, P = 0.02), particularly in the first 2 weeks of exposure. Dialysis efficacy was comparable with both dialysates. CONCLUSIONS: It can be confirmed that CiDi is not associated with the development of severe calcium and acid-base disorders, even when dialysis modalities with higher citrate loads are used. However, a refinement of the CiDi composition to minimize AEs is necessary.


Assuntos
Ácido Cítrico/farmacologia , Soluções para Diálise/farmacologia , Hipercalcemia/prevenção & controle , Falência Renal Crônica/terapia , Diálise Renal/métodos , Adulto , Idoso , Quelantes de Cálcio/farmacologia , Estudos Cross-Over , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
18.
Nature ; 464(7289): 721-7, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-20360735

RESUMO

Despite our rapidly growing knowledge about the human genome, we do not know all of the genes required for some of the most basic functions of life. To start to fill this gap we developed a high-throughput phenotypic screening platform combining potent gene silencing by RNA interference, time-lapse microscopy and computational image processing. We carried out a genome-wide phenotypic profiling of each of the approximately 21,000 human protein-coding genes by two-day live imaging of fluorescently labelled chromosomes. Phenotypes were scored quantitatively by computational image processing, which allowed us to identify hundreds of human genes involved in diverse biological functions including cell division, migration and survival. As part of the Mitocheck consortium, this study provides an in-depth analysis of cell division phenotypes and makes the entire high-content data set available as a resource to the community.


Assuntos
Divisão Celular/genética , Genoma Humano/genética , Microscopia de Fluorescência/métodos , Fenótipo , Animais , Movimento Celular/genética , Sobrevivência Celular/genética , Cor , Técnicas de Silenciamento de Genes , Genes/genética , Células HeLa , Humanos , Cinética , Camundongos , Mitose/genética , Interferência de RNA , Reprodutibilidade dos Testes , Fuso Acromático/genética , Fuso Acromático/metabolismo , Fatores de Tempo
19.
Pediatr Crit Care Med ; 17(11): 1080-1087, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27632059

RESUMO

OBJECTIVE: To evaluate the outcomes associated with the use of inhaled nitric oxide during extracorporeal membrane oxygenation. DESIGN: Post hoc analysis of data from an existing administrative national database, Pediatric Health Information system (2004-2014). Multivariable logistic regression models were fitted to study the effect of inhaled nitric oxide during extracorporeal membrane oxygenation on study outcomes. SETTING: Forty-two children's hospitals across the United States. PATIENTS: Patients in the age group from 1 day through 18 years admitted to an ICU who received extracorporeal membrane oxygenation during their hospital stay were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In total, 6,419 patients qualified for inclusion. Of these, inhaled nitric oxide was used among 3,629 patients during extracorporeal membrane oxygenation run. Approximately one half of the study patients received inhaled nitric oxide at extracorporeal membrane oxygenation initiation. The proportion of patients receiving inhaled nitric oxide during extracorporeal membrane oxygenation decreased with increasing duration of extracorporeal membrane oxygenation. After adjusting for patient characteristics and center variables, use of inhaled nitric oxide was not associated with any survival benefit. However, higher proportion of patients receiving inhaled nitric oxide were associated with prolonged hospital length of stay and prolonged duration of extracorporeal membrane oxygenation. In adjusted models, the hospital charges were higher in the inhaled nitric oxide group. The median hospital costs among patients receiving inhaled nitric oxide were higher by $39,732 (95% CI, $31,074-48,390) as compared to the patients who did not receive inhaled nitric oxide, after adjusting for patient (including hospital length of stay) and center level variables. As the duration of inhaled nitric oxide therapy increased, proportion of patients with prolonged duration of extracorporeal membrane oxygenation and prolonged hospital length of stay increased. CONCLUSIONS: This large observational analysis of use of nitric oxide during extracorporeal membrane oxygenation calls into question the benefits of inhaled nitric oxide among patients receiving extracorporeal membrane oxygenation for pulmonary or cardiac failure. Given our inability to determine type of extracorporeal membrane oxygenation and control for severity of illness, these findings should be interpreted as exploratory.


Assuntos
Oxigenação por Membrana Extracorpórea , Hipertensão Pulmonar/terapia , Óxido Nítrico/uso terapêutico , Vasodilatadores/uso terapêutico , Administração por Inalação , Adolescente , Criança , Pré-Escolar , Terapia Combinada , Bases de Dados Factuais , Feminino , Humanos , Hipertensão Pulmonar/mortalidade , Lactente , Recém-Nascido , Modelos Lineares , Modelos Logísticos , Masculino , Análise Multivariada , Taxa de Sobrevida , Resultado do Tratamento , Estados Unidos/epidemiologia
20.
J Oncol Pharm Pract ; 22(3): 523-7, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25655468

RESUMO

We report a patient with refractory diffuse large B-cell lymphoma who developed irreversible, severe spinal neurotoxicity after concurrent treatment with intrathecal and systemic cytarabine. Shortly after concomitant administration of intrathecal triple therapy (MTX, dexamethasone and cytarabine) and high-dose systemic cytarabin (R-DHAP protocol) the patient lost control of bowel and bladder function and developed an ascending, irreversible paraplegia. Infectious or neoplastic diseases of the spinal cord were ruled out. A magnetic resonance imaging scan of the spine resulted in a diagnosis of toxic myelitis. Previously observed cases of spinal neurotoxicity after cytarabine treatment are reviewed as well as current guidelines for the use of intrathecal chemotherapy in high-grade non-Hodgkin lymphoma. In summary, severe spinal neurotoxicity of intrathecal chemotherapy is a rare side-effect, however several studies suggest that the neurotoxicity of cytarabine is significantly enhanced by concurrent intrathecal and high-dose systemic administration. Simultaneous high-dose systemic and intrathecal chemotherapy with cytarabine should therefore be avoided.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Índice de Gravidade de Doença , Doenças da Medula Espinal/induzido quimicamente , Idoso , Cisplatino/administração & dosagem , Cisplatino/efeitos adversos , Citarabina/administração & dosagem , Citarabina/efeitos adversos , Dexametasona/administração & dosagem , Dexametasona/efeitos adversos , Humanos , Injeções Espinhais , Linfoma Difuso de Grandes Células B/diagnóstico por imagem , Masculino , Doenças da Medula Espinal/diagnóstico por imagem , Resultado do Tratamento
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