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2.
J Cell Mol Med ; 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31886938

RESUMO

Aortic root aneurysm formation is a cardinal feature of Marfan syndrome (MFS) and likely TGF-ß driven via Smad (canonical) and ERK (non-canonical) signalling. The current study assesses human MFS vascular smooth muscle cell (SMC) phenotype, focusing on individual contributions by Smad and ERK, with Notch3 signalling identified as a novel compensatory mechanism against TGF-ß-driven pathology. Although significant ERK activation and mixed contractile gene expression patterns were observed by traditional analysis, this did not directly correlate with the anatomic site of the aneurysm. Smooth muscle cell phenotypic changes were TGF-ß-dependent and opposed by ERK in vitro, implicating the canonical Smad pathway. Bulk SMC RNA sequencing after ERK inhibition showed that ERK modulates cell proliferation, apoptosis, inflammation, and Notch signalling via Notch3 in MFS. Reversing Notch3 overexpression with siRNA demonstrated that Notch3 promotes several protective remodelling pathways, including increased SMC proliferation, decreased apoptosis and reduced matrix metalloproteinase activity, in vitro. In conclusion, in human MFS aortic SMCs: (a) ERK activation is enhanced but not specific to the site of aneurysm formation; (b) ERK opposes TGF-ß-dependent negative effects on SMC phenotype; (c) multiple distinct SMC subtypes contribute to a 'mixed' contractile-synthetic phenotype in MFS aortic aneurysm; and (d) ERK drives Notch3 overexpression, a potential pathway for tissue remodelling in response to aneurysm formation.

3.
SLAS Discov ; : 2472555219883623, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31855104

RESUMO

Mono(ADP-ribosylation) (MARylation) and poly(ADP-ribosylation) (PARylation) are posttranslational modifications found on multiple amino acids. There are 12 enzymatically active mono(ADP-ribose) polymerase (monoPARP) enzymes and 4 enzymatically active poly(ADP-ribose) polymerase (polyPARP) enzymes that use nicotinamide adenine dinucleotide (NAD+) as the ADP-ribose donating substrate to generate these modifications. While there are approved drugs and clinical trials ongoing for the enzymes that perform PARylation, MARylation is gaining recognition for its role in immune function, inflammation, and cancer. However, there is a lack of chemical probes to study the function of monoPARPs in cells and in vivo. An important first step to generating chemical probes for monoPARPs is to develop biochemical assays to enable hit finding, and determination of the potency and selectivity of inhibitors. Complicating the development of enzymatic assays is that it is poorly understood how monoPARPs engage their substrates. To overcome this, we have developed a family-wide approach to developing robust high-throughput monoPARP assays where the enzymes are immobilized and forced to self-modify using biotinylated-NAD+, which is detected using a dissociation-enhanced lanthanide fluorescence immunoassay (DELFIA) readout. Herein we describe the development of assays for 12 monoPARPs and 3 polyPARPs and apply them to understand the potency and selectivity of a focused library of inhibitors across this family.

4.
J Knee Surg ; 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31752023

RESUMO

Subchondroplasty is a relatively new joint preserving procedure, which involves the localized injection of calcium pyrophosphate bone substitute into the bone marrow lesion. The advent of magnetic resonance imaging (MRI) has greatly facilitated the identification of these bone marrow lesions. We investigated the clinical efficacy of subchondroplasty in the treatment of symptomatic bone marrow lesions in the knee, including knees with preexisting osteoarthritis. This study comprised of 12 patients whose knees were evaluated with standard radiographs and MRI to identify and localize the bone marrow lesions. They then underwent subchondroplasty under intraoperative radiographic guidance. Preoperative and postoperative visual analog scale (VAS) pain scores, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and Knee Injury and Arthritis Outcome Scores (KOOS) were obtained. VAS scores improved significantly from 7.5 ± 1.8 before surgery to 5.2 ± 2.7 after surgery. This further improved to 2.1 ± 2.4 at the one-year follow-up. KOOS scores improved significantly from 38.5 ± 17.0 before surgery to 73.2 ± 19.0 at the one-year follow-up. WOMAC scores improved significantly from 47.8 ± 20.5 before surgery to 14.3 ± 13.2 at the one-year follow-up. Subchondroplasty offers an effective way to treat subchondral bone marrow lesions in the arthritic knee, resulting in improvement in symptoms and early return to activity. Long-term studies are required to evaluate if these benefits can last. This is a Level II study.

5.
Pediatr Neonatol ; 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31296400

RESUMO

BACKGROUND: To evaluate the occurrence of constipation after anorectal malformations (ARM) repair and the results of laxative treatment. METHODS: Between August 2012 and July 2017, the clinical data of patients with ARMs was prospectively collected. The patients were divided into two groups, good types and poor types. Good types included rectoperineal, rectovestibular, rectourethral bulbar, and no fistula. Risk factors were defined as spinal cord anomalies, sacral ratio <0.4, or cognitive impairment. Success was defined as that laxative could be tapered. RESULTS: Eighty-four patients were enrolled with mean age of 6.3 ± 7.8 (0.6-59.9) years. The mean age of onset of constipation was 12.8 ± 8.3 months and the mean interval was 5.9 ± 5.1 months after reconstructions. The interval was not significantly different between patients with good types and poor types. In 23 patients with severe constipation being treated for >6 months, 14 of 18 (77.8%) patients with good types were classified as success, whereas only 1 of 5 (20%) patients with poor types was (p = 0.02). In patients with good types, 9 of 9 (100%) patients with no risk factors were successful; however, only 5 out of 9 (55.6%) patients with risk factors were successful (p = 0.02). CONCLUSION: Constipation occurs shortly after operations. Patients with good types and no risk factors are susceptible to weaning laxatives.

6.
Am J Cardiol ; 123(10): 1628-1636, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30846214

RESUMO

Systolic blood pressure (SBP) and its association with clinical outcomes in atrial fibrillation (AF) patients in community practice are poorly characterized. In patients with AF, we sought to (1) examine the prevalence of baseline uncontrolled hypertension and the overall change in SBP control, (2) identify predictors of uncontrolled SBP over 2 years of follow-up, and (3) determine the relation between SBP and clinical outcomes. We analyzed 10,132 patients with AF at 176 clinics in the ORBIT-AF registry between 2010 and 2014, classified as: (1) no history of hypertension; (2) controlled hypertension (baseline SBP <140 mm Hg); (3) and uncontrolled hypertension (baseline SBP >140 mm Hg). Predictors of SBP >140 mm Hg at baseline or in follow-up were identified with pooled logistic regression. Random effects Cox regression models were used to compare cardiovascular outcomes and major bleeding as a function of continuous, time-dependent SBP. Overall 8,383 (83%) of patients with AF had hypertension. Of these, 24.2% (n = 2032) had uncontrolled baseline SBP, with little change over 2 years. Predictors of elevated follow-up SBP included uncontrolled baseline SBP, females, previous percutaneous coronary intervention, and diabetes. For every 5 mm Hg increase in follow-up SBP, the adjusted risk of stroke or systemic embolism or transient ischemic attack (adjusted hazard ratio [aHR] 1.05, 95% confidence interval [CI] 1.01 to 1.08, p = 0.01), myocardial infarction (aHR 1.05, 95% CI 1.00 to 1.11, p = 0.04), and major bleeding (aHR 1.03, 95% CI 1.00 to 1.06, p = 0.04) increased modestly. In conclusion, in patients with AF, higher SBP was associated with increasing adverse events; therefore, more rigorous blood pressure control should be emphasized.

9.
Acad Radiol ; 26(4): 566-577, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30424998

RESUMO

RATIONALE AND OBJECTIVES: Artificial intelligence (AI) has the potential to transform the clinical practice of radiology. This study investigated Canadian medical students' perceptions of the impact of AI on radiology, and their influence on the students' preference for radiology specialty. MATERIALS AND METHODS: In March 2018, an anonymous online survey was distributed to students at all 17 Canadian medical schools. RESULTS: Among 322 respondents, 70 students considered radiology as the top specialty choice, and 133 as among the top three choices. Only a minority (29.3%) of respondents agreed AI would replace radiologists in foreseeable future, but a majority (67.7%) agreed AI would reduce the demand for radiologists. Even among first-choice respondents, 48.6% agreed AI caused anxiety when considering the radiology specialty. Furthermore, one-sixth of respondents who would otherwise rank radiology as the first choice would not consider radiology because of the anxiety about AI. Prior significant exposure to radiology and high confidence in understanding of AI were shown to decrease the anxiety level. Interested students valued the opinions of local radiologists, radiology conferences, and journals. Students were most interested in "expert opinions on AI" and "discussing AI in preclinical radiology lectures" to understand the impact of AI. CONCLUSION: Anxiety related to "displacement" (not "replacement") of radiologists by AI discouraged many medical students from considering the radiology specialty. The radiology community should educate medical students about the potential impact of AI, to ensure radiology is perceived as a viable long-term career choice.

11.
J Pediatr Surg ; 54(8): 1604-1608, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30121127

RESUMO

BACKGROUND: The aim of this study is to evaluate the feasibility of single-incision laparoscopic surgery (SILS) for idiopathic intussusception in children and compare the outcomes with conventional laparoscopy (CLS). METHODS: Between January 2011 and December 2012, patients who underwent CLS for idiopathic intussusception were assigned into the group of CLS. Between January 2013 and March 2017, patients who underwent SILS were assigned to the group of SILS. For patients who failed to reduce by SILS, bimanual transabdominal approach was conducted. RESULTS: A total of 23 patients were enrolled, including 7 and 16 patients in SILS and CLS, respectively. The mean age was similar in both group (22.4 ±â€¯18.7 vs. 24.6 ±â€¯18.6 months, p = 0.80). There is no difference in gender distribution. The main indication was radiological reduction failure in both groups (85.7% vs. 75%, p = 0.58). Ileocolic intussusception was found in 6 (85.7%) and 15 (93.8%) patients of SILS and CLS, respectively (p = 0.25). The level of intussusception was at ascending colon in 3 (42.9%) and 12 (75.0%) patients, respectively (p = 0.11). The operation time was similar in both groups (64.9 ±â€¯53.7 and 70.9 ±â€¯26.1 min, p = 0.79). There were 2 (28.6%) and 1 (6.2%) conversions, respectively (p = 0.15). For the two patients in SILS, the intussusception was successfully reduced by bimanual transabdominal approach. There was no significant difference in time to feeding (1.9 ±â€¯1.1 vs. 1.4 ±â€¯0.7 days, p = 0.21). The mean length of postoperative hospital stay was 3.9 ±â€¯1.6 and 3.1 ±â€¯1.1 days, respectively (p = 0.17). CONCLUSIONS: SILS for pediatric intussusception is technically feasible and has comparable results to CLS. Transabdominal bimanual reduction is applicable in cases of failed laparoscopic reduction. LEVEL OF EVIDENCE: III.


Assuntos
Doenças do Íleo/cirurgia , Intussuscepção/cirurgia , Laparoscopia , Pré-Escolar , Humanos , Lactente , Laparoscopia/efeitos adversos , Laparoscopia/métodos , Laparoscopia/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Duração da Cirurgia
12.
J Digit Imaging ; 32(1): 6-18, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30076490

RESUMO

In today's radiology workflow, free-text reporting is established as the most common medium to capture, store, and communicate clinical information. Radiologists routinely refer to prior radiology reports of a patient to recall critical information for new diagnosis, which is quite tedious, time consuming, and prone to human error. Automatic structuring of report content is desired to facilitate such inquiry of information. In this work, we propose an unsupervised machine learning approach to automatically structure radiology reports by detecting and normalizing anatomical phrases based on the Systematized Nomenclature of Medicine-Clinical Terms (SNOMED CT) ontology. The proposed approach combines word embedding-based semantic learning with ontology-based concept mapping to derive the desired concept normalization. The word embedding model was trained using a large corpus of unlabeled radiology reports. Fifty-six anatomical labels were extracted from SNOMED CT as class labels of the whole human anatomy. The proposed framework was compared against a number of state-of-the-art supervised and unsupervised approaches. Radiology reports from three different clinical sites were manually labeled for testing. The proposed approach outperformed other techniques yielding an average precision of 82.6%. The proposed framework boosts the coverage and performance of conventional approaches for concept normalization, by applying word embedding techniques in semantic learning, while avoiding the challenge of having access to a large amount of annotated data, which is typically required for training classifiers.

13.
Pediatr Neonatol ; 60(3): 318-323, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30145106

RESUMO

BACKGROUND: The purpose of this study is to examine the outcome of transumbilical minilaparotomy for infants and compare the results between normal birthweight (NBW) and low birthweight (LBW). METHODS: Between July 2010 and March 2017, infants who underwent abdominal surgery through transumbilical minilaparotomy were enrolled. Medical records were retrospectively reviewed. Patients were divided into two groups, NBW and LBW. Complexity was defined as complicated conditions other than intestinal atresia and malrotation. RESULTS: Totally, 16 patients were included. The diagnosis included intestinal atresia (n = 3), meconium peritonitis (n = 4), bowel infarction/necrosis (n = 4), spontaneous intestinal perforation (n = 2), segmental volvulus and necrosis (n = 1), necrotizing enterocolitis (n = 1), and malrotation (n = 1). The median gestational age and body weight were 32 (24-40) weeks and 1731 (560-4200) grams respectively. The median age at operation was 3 (1-41) days. The surgical procedure included primary repair of the intestine (n = 14), ileostomy (n = 1) and Ladd's procedure (n = 1). Postoperative complications included anastomotic leakage (n = 2), adhesion ileus (n = 1), and missed rectal atresia (n = 1). There was one mortality due to extremely low birthweight and poor lung maturation. Re-operation was required in 3 patients for anastomotic leakage (n = 2) and missed rectal atresia (n = 1). Mean birthweight was 2932 ± 97 and 1263 ± 667 g in NBW (n = 5) and LBW (n = 11), respectively (p < 0.01). Complexity rate was 40% and 90.9%, respectively (p = 0.034). The mean operation time was 139.4 ± 65.8 and 124.3 ± 46.1 min, respectively (p = 0.60). The complicated rate and reoperation rate were similar. CONCLUSIONS: Transumbilical minilaparotomy is technically feasible and an alternative option of minimally invasive surgery for LBW infants and complex conditions.


Assuntos
Recém-Nascido de Baixo Peso , Laparotomia/métodos , Peso ao Nascer , Enterocolite Necrosante/cirurgia , Feminino , Humanos , Lactente , Recém-Nascido , Atresia Intestinal/cirurgia , Volvo Intestinal/cirurgia , Masculino , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Umbigo/cirurgia
14.
Methods Mol Biol ; 1813: C1, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30488319

RESUMO

The funding information was omitted from the original Chapters 19 and 21. The below text has been added to these chapters respectively.

15.
Clin Transplant ; 32(12): e13428, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30338873

RESUMO

Simultaneous liver-kidney allocation protocols allocate dual organs based on a sustained eGFR of 30 mL/min or less. A 2017-UNOS update includes CKD3 as dual organ candidates but only when the listing eGFR is <30 mL/min while recommending a "safety net" for prioritized kidney listing post-LT. We retrospectively reviewed adult LTs examine whether the UNOS proposal captured the LT population at highest risk for developing post-LT ESRD. Among 290 LT recipients, 67 had pre-LT CKD3, 141 had AKI, of whom 47 required dialysis (<4 weeks). During follow-up, 25 (8.62%) developed ESRD, while 70 (24.1%) died. In adjusted Cox models, CKD3 had an independent association with post-LT ESRD (adjusted HR 4.8; P = 0.001), independent of AKI. Interestingly, CKD3 with listing GFR >30 mL/min was still significantly associated with post-LT ESRD. AKI was associated with reduced post-LT survival (adjusted HR 1.9; P = 0.02), albeit only in the first-year post-LT. Severe AKI-D was associated with post-LT ESRD and mortality. The safety net would have captured only 60% of all post-LT ESRD cases in our cohort. Pre-LT CKD3 was associated with increased risk of post-LT ESRD above the recommended cutoff for listing GFR. These findings, if generalizable in larger cohorts have important implications for dual organ allocation.


Assuntos
Doença Hepática Terminal/mortalidade , Rejeição de Enxerto/mortalidade , Sobrevivência de Enxerto , Falência Renal Crônica/complicações , Transplante de Fígado/mortalidade , Complicações Pós-Operatórias/mortalidade , Insuficiência Renal/complicações , Idoso , Estudos de Casos e Controles , Doença Hepática Terminal/cirurgia , Feminino , Seguimentos , Taxa de Filtração Glomerular , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/patologia , Humanos , Testes de Função Renal , Transplante de Fígado/efeitos adversos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/patologia , Prognóstico , Sistema de Registros , Estudos Retrospectivos , Fatores de Risco
16.
NMR Biomed ; 31(12): e4014, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30334288

RESUMO

The aim of this work was to use post-processing methods to improve the data quality of metabolite maps acquired on the human brain at 9.4 T with accelerated acquisition schemes. This was accomplished by combining an improved sensitivity encoding (SENSE) reconstruction with a B0 correction of spatially over-discretized magnetic resonance spectroscopic imaging (MRSI) data. Since MRSI scans suffer from long scan duration, investigating different acceleration techniques has recently been the focus of several studies. Due to strong B0 inhomogeneity and strict specific absorption rate (SAR) limitations at ultra-high fields, the use of a low-SAR sequence combined with an acceleration technique that is compatible with dynamic B0 shim updating is preferable. Hence, in this study, a non-lipid-suppressed ultra-short TE and TR 1 H free induction decay MRSI sequence is combined with an in-plane SENSE acceleration technique to obtain high-resolution metabolite maps in a clinically feasible scan time. One of the major issues in applying parallel imaging techniques to non-lipid-suppressed MRSI is the presence of strong lipid aliasing artifacts, which if not thoroughly resolved will hinder the accurate quantification of the metabolites of interest. To achieve a more robust reconstruction, an over-discretized SENSE reconstruction (with direct control over the shape of the spatial response function) was combined with an over-discretized B0 correction. This method is compared with conventional SENSE reconstruction for seven acceleration schemes on four healthy volunteers. The over-discretized method consistently outperformed conventional SENSE, resulting in an average of 23 ± 1.2% higher signal-to-noise ratio and 8 ± 2.9% less error in the fitting of the N-acetylaspartate signal over a whole brain slice. The highest achievable acceleration factor with the proposed technique was determined to be 4. Finally, using the over-discretized method, high-resolution (97 µL nominal voxel size) metabolite maps can be acquired in 3.75 min at 9.4 T. This enables the acquisition of high-resolution metabolite maps with more spatial coverage at ultra-high fields.


Assuntos
Algoritmos , Encéfalo/diagnóstico por imagem , Lipídeos/química , Imagem por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Mapeamento Encefálico , Humanos , Metaboloma , Razão Sinal-Ruído
17.
Methods Mol Biol ; 1813: 327-341, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30097879

RESUMO

Posttranscriptional regulation of RNA is an important component of gene expression by controlling the total amount of mRNA available for translation into protein. It involves multiple pathways including nuclear processing of mRNA and its precursors, RNA silencing, and regulation of RNA decay. Poly(ADP-ribose) polymerases (PARPs), enzymes that modify target proteins with ADP-ribose, play important roles in several RNA-regulatory pathways. RNA-binding PARPs target specific transcripts for regulation, and multiple PARPs ADP-ribosylate RNA-regulatory proteins to alter their localization, activity, or RNA binding. Additionally, RNA-binding proteins can bind directly to poly(ADP-ribose) with various effects on their function. Here we describe methods to identify and confirm specific transcripts that are regulated by PARPs.


Assuntos
Biologia Molecular/métodos , Poli(ADP-Ribose) Polimerases/genética , Proteínas de Ligação a RNA/genética , RNA/genética , Regulação da Expressão Gênica , Humanos , Poli Adenosina Difosfato Ribose/genética , Processamento de Proteína Pós-Traducional , Transporte Proteico , RNA/isolamento & purificação , Estabilidade de RNA/genética , Proteínas de Ligação a RNA/isolamento & purificação
19.
Neuroimage ; 183: 336-345, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30125713

RESUMO

Magnetic resonance spectroscopic imaging (MRSI) is a powerful tool for mapping metabolite levels across the brain, however, it generally suffers from long scan times. This severely hinders its application in clinical settings. Additionally, the presence of nuisance signals (e.g. the subcutaneous lipid signals close to the skull region in brain metabolite mapping) makes it challenging to apply conventional acceleration techniques to shorten the scan times. The goal of this work is, therefore, to increase the overall applicability of high resolution metabolite mapping using 1H MRSI by introducing a novel GRAPPA acceleration acquisition/reconstruction technique. An improved reconstruction method (MultiNet) is introduced that uses machine learning, specifically neural networks, to reconstruct accelerated data. The method is further modified to use more neural networks with nonlinear hidden layers and is then combined with a variable density undersampling scheme (MultiNet PyGRAPPA) to enable higher in-plane acceleration factors of R = 5.6 and R = 7 for a non-lipid suppressed ultra-short TR and TE 1H FID MRSI sequence. The proposed method is evaluated for high resolution metabolite mapping of the human brain at 9.4T. The results show that the proposed method is superior to conventional GRAPPA: there is no significant residual lipid aliasing artifact in the images when the proposed MultiNet method is used. Furthermore, the MultiNet PyGRAPPA acquisition/reconstruction method with R = 5.6 results in reproducible high resolution metabolite maps (with an in-plane matrix size of 64 × 64) that can be acquired in 2.8 min on 9.4T. In conclusion, using multiple neural networks to predict the missing points in GRAPPA reconstruction results in a more reliable data recovery while keeping the noise levels under control. Combining this high fidelity reconstruction with variable density undersampling (MultiNet PyGRAPPA) enables higher in-plane acceleration factors even for non-lipid suppressed 1H FID MRSI, without introducing any structured aliasing artifact in the image.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Processamento de Imagem Assistida por Computador/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Adulto , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Ácido Glutâmico/metabolismo , Humanos , Processamento de Imagem Assistida por Computador/normas , Espectroscopia de Prótons por Ressonância Magnética/normas , Reprodutibilidade dos Testes
20.
Am J Physiol Cell Physiol ; 315(5): C623-C635, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30044662

RESUMO

The connexins are members of a family of integral membrane proteins that form gap junction channels between apposed cells and/or hemichannels across the plasma membranes. The importance of the arginine at position 76 (Arg76) in the structure and/or function of connexin 46 (Cx46) is highlighted by its conservation across the entire connexin family and the occurrence of pathogenic mutations at this (or the corresponding homologous) residue in a number of human diseases. Two mutations at Arg76 in Cx46 are associated with cataracts in humans, highlighting the importance of this residue. We examined the expression levels and macroscopic and single-channel properties of human Cx46 and compared them with those for two pathogenic mutants, namely R76H and R76G. To gain further insight into the role of charge at this position, we generated two additional nonnaturally occurring mutants, R76K (charge conserving) and R76E (charge inverting). We found that, when expressed exogenously in Neuro2a cells, all four mutants formed membrane hemichannels, inducing membrane permeability at levels comparable to those recorded in cells expressing the wild-type Cx46. In contrast, the number of gap-junction plaques and the magnitude of junctional coupling were reduced by all four mutations. To gain further insight into the role of Arg76 in the function of Cx46, we performed homology modeling of Cx46 and in silico mutagenesis of Arg76 to Gly, His, or Glu. Our studies suggest that the loss of interprotomeric interactions has a significant effect on the extracellular domain conformation and dynamics, thus affecting the hemichannel docking required for formation of cell-cell channels.


Assuntos
Catarata/genética , Permeabilidade da Membrana Celular/genética , Conexinas/genética , Junções Comunicantes/genética , Arginina/genética , Catarata/patologia , Simulação por Computador , Regulação da Expressão Gênica/genética , Células HeLa , Humanos , Canais Iônicos/genética , Mutação/genética
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