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1.
Nature ; 620(7974): 516-520, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37488359

RESUMO

Terrestrial and sub-Neptune planets are expected to form in the inner (less than 10 AU) regions of protoplanetary disks1. Water plays a key role in their formation2-4, although it is yet unclear whether water molecules are formed in situ or transported from the outer disk5,6. So far Spitzer Space Telescope observations have only provided water luminosity upper limits for dust-depleted inner disks7, similar to PDS 70, the first system with direct confirmation of protoplanet presence8,9. Here we report JWST observations of PDS 70, a benchmark target to search for water in a disk hosting a large (approximately 54 AU) planet-carved gap separating an inner and outer disk10,11. Our findings show water in the inner disk of PDS 70. This implies that potential terrestrial planets forming therein have access to a water reservoir. The column densities of water vapour suggest in-situ formation via a reaction sequence involving O, H2 and/or OH, and survival through water self-shielding5. This is also supported by the presence of CO2 emission, another molecule sensitive to ultraviolet photodissociation. Dust shielding, and replenishment of both gas and small dust from the outer disk, may also play a role in sustaining the water reservoir12. Our observations also reveal a strong variability of the mid-infrared spectral energy distribution, pointing to a change of inner disk geometry.

2.
Mol Cell ; 81(8): 1631-1639, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33826920

RESUMO

Spatial transcriptional profiling provides gene expression information within the important anatomical context of tissue architecture. This approach is well suited to characterizing solid tumors, which develop within a complex landscape of malignant cells, immune cells, and stroma. In a single assay, spatial transcriptional profiling can interrogate the role of spatial relationships among these cell populations as well as reveal spatial patterns of relevant oncogenic genetic events. The broad utility of this approach is reflected in the array of strategies that have been developed for its implementation as well as in the recent commercial development of several profiling platforms. The flexibility to apply these technologies to both hypothesis-driven and discovery-driven studies allows widespread applicability in research settings. This review discusses available technologies for spatial transcriptional profiling and several applications for their use in cancer research.


Assuntos
Perfilação da Expressão Gênica/métodos , Neoplasias/genética , Transcrição Gênica/genética , Animais , Expressão Gênica/genética , Humanos
3.
PLoS Genet ; 20(7): e1011343, 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-39052672

RESUMO

Maternally-loaded factors in the egg accumulate during oogenesis and are essential for the acquisition of oocyte and egg developmental competence to ensure the production of viable embryos. However, their molecular nature and functional importance remain poorly understood. Here, we present a collection of 9 recessive maternal-effect mutants identified in a zebrafish forward genetic screen that reveal unique molecular insights into the mechanisms controlling the vertebrate oocyte-to-embryo transition. Three genes, over easy, p33bjta, poached and black caviar, were found to control initial steps in yolk globule sizing and protein cleavage during oocyte maturation that act independently of nuclear maturation. The krang, kazukuram, p28tabj, and spotty genes play distinct roles in egg activation, including cortical granule biology, cytoplasmic segregation, the regulation of microtubule organizing center assembly and microtubule nucleation, and establishing the basic body plan. Furthermore, we cloned two of the mutant genes, identifying the over easy gene as a subunit of the Adaptor Protein complex 5, Ap5m1, which implicates it in regulating intracellular trafficking and yolk vesicle formation. The novel maternal protein Krang/Kiaa0513, highly conserved in metazoans, was discovered and linked to the function of cortical granules during egg activation. These mutant genes represent novel genetic entry points to decipher the molecular mechanisms functioning in the oocyte-to-embryo transition, fertility, and human disease. Additionally, our genetic adult screen not only contributes to the existing knowledge in the field but also sets the basis for future investigations. Thus, the identified maternal genes represent key players in the coordination and execution of events prior to fertilization.

4.
Nature ; 586(7827): 145-150, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32968273

RESUMO

Natural products serve as chemical blueprints for most antibiotics in clinical use. The evolutionary process by which these molecules arise is inherently accompanied by the co-evolution of resistance mechanisms that shorten the clinical lifetime of any given class of antibiotics1. Virginiamycin acetyltransferase (Vat) enzymes are resistance proteins that provide protection against streptogramins2, potent antibiotics against Gram-positive bacteria that inhibit the bacterial ribosome3. Owing to the challenge of selectively modifying the chemically complex, 23-membered macrocyclic scaffold of group A streptogramins, analogues that overcome the resistance conferred by Vat enzymes have not been previously developed2. Here we report the design, synthesis, and antibacterial evaluation of group A streptogramin antibiotics with extensive structural variability. Using cryo-electron microscopy and forcefield-based refinement, we characterize the binding of eight analogues to the bacterial ribosome at high resolution, revealing binding interactions that extend into the peptidyl tRNA-binding site and towards synergistic binders that occupy the nascent peptide exit tunnel. One of these analogues has excellent activity against several streptogramin-resistant strains of Staphylococcus aureus, exhibits decreased rates of acetylation in vitro, and is effective at lowering bacterial load in a mouse model of infection. Our results demonstrate that the combination of rational design and modular chemical synthesis can revitalize classes of antibiotics that are limited by naturally arising resistance mechanisms.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Desenho de Fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Estreptogramina Grupo A/síntese química , Estreptogramina Grupo A/farmacologia , Acetilação/efeitos dos fármacos , Acetiltransferases/genética , Acetiltransferases/metabolismo , Animais , Antibacterianos/classificação , Carga Bacteriana/efeitos dos fármacos , Sítios de Ligação , Microscopia Crioeletrônica , Feminino , Técnicas In Vitro , Camundongos , Testes de Sensibilidade Microbiana , Modelos Moleculares , RNA de Transferência/metabolismo , Ribossomos/efeitos dos fármacos , Ribossomos/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Estreptogramina Grupo A/química , Estreptogramina Grupo A/classificação , Virginiamicina/análogos & derivados , Virginiamicina/química , Virginiamicina/metabolismo
5.
Bioessays ; 45(8): e2300029, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37183938

RESUMO

The endoplasmic reticulum (ER) organelle is the key intracellular site of both protein and lipid biosynthesis. ER dysfunction, termed ER stress, can result in protein accretion within the ER and cell death; a pathophysiological process contributing to a range of metabolic diseases and cancers. ER stress leads to the activation of a protective signalling cascade termed the Unfolded Protein Response (UPR). However, chronic UPR activation can ultimately result in cellular apoptosis. Emerging evidence suggests that cells undergoing ER stress and UPR activation can release extracellular signals that can propagate UPR activation to target tissues in a cell non-autonomous signalling mechanism. Separately, studies have determined that the UPR plays a key regulatory role in the biosynthesis of bioactive signalling lipids including sphingolipids and ceramides. Here we weigh the evidence to combine these concepts and propose that during ER stress, UPR activation drives the biosynthesis of ceramide lipids, which are exported and function as cell non-autonomous signals to propagate UPR activation in target cells and tissues.


Assuntos
Metabolismo dos Lipídeos , Resposta a Proteínas não Dobradas , Estresse do Retículo Endoplasmático , Comunicação , Lipídeos
6.
Diabetologia ; 67(7): 1413-1428, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38662134

RESUMO

AIMS/HYPOTHESIS: Our aim was to characterise the in-depth metabolic response to aerobic exercise and the impact of residual pancreatic beta cell function in type 1 diabetes. We also aimed to use the metabolome to distinguish individuals with type 1 diabetes with reduced maximal aerobic capacity in exercise defined by V ˙ O 2peak . METHODS: Thirty participants with type 1 diabetes (≥3 years duration) and 30 control participants were recruited. Groups did not differ in age or sex. After quantification of peak stimulated C-peptide, participants were categorised into those with undetectable (<3 pmol/l), low (3-200 pmol/l) or high (>200 pmol/l) residual beta cell function. Maximal aerobic capacity was assessed by V ˙ O 2peak test and did not differ between control and type 1 diabetes groups. All participants completed 45 min of incline treadmill walking (60% V ˙ O 2peak ) with venous blood taken prior to exercise, immediately post exercise and after 60 min recovery. Serum was analysed using targeted metabolomics. Metabolomic data were analysed by multivariate statistics to define the metabolic phenotype of exercise in type 1 diabetes. Receiver operating characteristic (ROC) curves were used to identify circulating metabolomic markers of maximal aerobic capacity ( V ˙ O 2peak ) during exercise in health and type 1 diabetes. RESULTS: Maximal aerobic capacity ( V ˙ O 2peak ) inversely correlated with HbA1c in the type 1 diabetes group (r2=0.17, p=0.024). Higher resting serum tricarboxylic acid cycle metabolites malic acid (fold change 1.4, p=0.001) and lactate (fold change 1.22, p=1.23×10-5) differentiated people with type 1 diabetes. Higher serum acylcarnitines (AC) (AC C14:1, F value=12.25, p=0.001345; AC C12, F value=11.055, p=0.0018) were unique to the metabolic response to exercise in people with type 1 diabetes. C-peptide status differentially affected metabolic responses in serum ACs during exercise (AC C18:1, leverage 0.066; squared prediction error 3.07). The malic acid/pyruvate ratio in rested serum was diagnostic for maximal aerobic capacity ( V ˙ O 2peak ) in people with type 1 diabetes (ROC curve AUC 0.867 [95% CI 0.716, 0.956]). CONCLUSIONS/INTERPRETATION: The serum metabolome distinguishes high and low maximal aerobic capacity and has diagnostic potential for facilitating personalised medicine approaches to manage aerobic exercise and fitness in type 1 diabetes.


Assuntos
Diabetes Mellitus Tipo 1 , Exercício Físico , Metaboloma , Humanos , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/fisiopatologia , Masculino , Feminino , Adulto , Metaboloma/fisiologia , Exercício Físico/fisiologia , Consumo de Oxigênio/fisiologia , Teste de Esforço , Metabolômica/métodos , Adulto Jovem , Peptídeo C/sangue , Pessoa de Meia-Idade , Células Secretoras de Insulina/metabolismo
7.
Biol Reprod ; 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38904948

RESUMO

Conceptus estrogens and prostaglandins have long been considered the primary signals for maternal recognition of pregnancy (MRP) in the pig. However, loss-of-function studies targeting conceptus aromatase genes (CYP19A1 and CYP19A2) and prostaglandin-endoperoxide synthase 2 (PTGS2) indicated that conceptuses can not only signal MRP without estrogens or prostaglandins but can maintain early pregnancy. However, complete loss of estrogen production leads to abortion after day 25 of gestation. Although neither conceptus estrogens nor prostaglandins had a significant effect on early maintenance of CL function alone, the two conceptus factors have a biological relationship. To investigate the role that both conceptus estrogens and prostaglandins have on MRP and maintenance of pregnancy, a triple loss-of function model (TKO) was generated for conceptus CYP19A1, CYP19A2 and PTGS2. In addition, a conceptus CYP19A2-/- model (A2KO) was established to determine the role of placental estrogen during later pregnancy. Estrogen and prostaglandin synthesis were greatly reduced in TKO conceptuses which resulted in a failure to inhibit luteolysis after day 15 of pregnancy despite the presence of conceptuses in the uterine lumen. However, A2KO placentae not only maintained functional CL but were able to maintain pregnancy to day 32 of gestation. Despite the loss of placental CYP19A2 expression, the allantois fluid content of estrogen was not affected as the placenta compensated by expressing CYP19A1 and CYP19A3, which are normally absent in controls. Results suggest conceptuses can signal MRP through production of conceptus PGE or stimulating PGE synthesis from the endometrium through conceptus estrogen. Failure of conceptuses to produce both factors results in failure of MRP and loss of pregnancy.

8.
Genet Med ; : 101175, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38850131

RESUMO

PURPOSE: High costs of applying to genetic counseling graduate programs (GCGPs) are likely a barrier to workforce diversification. We sought to determine application costs and assess differences between individuals of historically underrepresented racial and ethnic backgrounds in medicine (hURM) and non-hURM applicants. METHODS: Applicants to GCGPs between 2005-2020 were surveyed about application history, related expenses, volunteer hours, and financial resources; 383 responses were analyzed. RESULTS: Median total application costs (MTAC) were $2,634, $4,762, and $5,607 (one, two, and three or more application cycles, respectively). Interview-related items (which includes travel) had the highest median cost (one application cycle: $879). Among those who applied to multiple cycles, hURM respondents had higher MTAC than those of non-hURM ($6,713 versus $4,762, p=0.03) and lower median total volunteer hours (246 versus 381, p=0.03). Parental education level differed by hURM status (p=0.04). Median financial contribution from parents with and without advanced degrees varied significantly (60% vs 2%, p=0.0009). CONCLUSION: Significant costs are incurred during the GCGP application process, but notable differences in costs and resources were observed between hURM and non-hURM applicants. Stakeholders within the profession should implement strategies to reduce financial barriers and the resulting inequities in the application process.

9.
Psychol Med ; 54(1): 1-12, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37818642

RESUMO

Suicide is the leading cause of unnatural death among people with a diagnosis of schizophrenia. Alcohol use is a prevalent comorbid feature of schizophrenia and a modifiable risk factor for suicide. We conducted a prospectively registered (PROSPERO, CRD42022358214) systematic review and meta-analysis to quantify the relationship between alcohol use and suicide-related outcomes in schizophrenia.We searched Medline, Embase, and PsycINFO for cross-sectional, case-control and longitudinal studies using exhaustive terms from database inception to December 2022 inclusive. Computation of odds ratios (ORs) and hazard ratios (HRs) were performed using a random-effects model with DerSimonian-Laird estimation. We also evaluated publication bias, study quality, and performed subgroup analysis and meta-regression. Fifty studies, comprising 65 samples, met eligibility criteria. Overall, alcohol use was associated with suicide (OR 1.38, 95% CI 1.21-1.58; HR = 1.32, 95% CI 1.00-1.74), attempted suicide (OR 1.69, 95% CI 1.45-1.98), and suicidal ideation (OR 1.69, 95% CI 1.22-2.34). While there was no evidence of publication bias, between-sample heterogeneity was moderate in analyses of attempted suicide (I2 = 39.6%, p = 0.01) and suicidal ideation (I2 = 56.0%, p = 0.01). Summary effects were significant in all subgroups except for longitudinal studies of attempted suicide (OR 1.60, 95% CI 0.86-3.00) and studies of suicidal ideation using gender combined samples (OR 1.63, 95% CI 0.99-2.67). Alcohol use is significantly associated with suicide-related outcomes in schizophrenia. Clinicians should routinely inquire about alcohol use in mental health services to focus preventative treatment efforts.


Assuntos
Esquizofrenia , Humanos , Esquizofrenia/epidemiologia , Estudos Transversais , Tentativa de Suicídio/psicologia , Ideação Suicida , Fatores de Risco
10.
Nat Chem Biol ; 18(2): 161-170, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34931064

RESUMO

Multi-enzyme assemblies composed of metabolic enzymes catalyzing sequential reactions are being increasingly studied. Here, we report the discovery of a 1.6 megadalton multi-enzyme complex from Bacillus subtilis composed of two enzymes catalyzing opposite ('counter-enzymes') rather than sequential reactions: glutamate synthase (GltAB) and glutamate dehydrogenase (GudB), which make and break glutamate, respectively. In vivo and in vitro studies show that the primary role of complex formation is to inhibit the activity of GudB. Using cryo-electron microscopy, we elucidated the structure of the complex and the molecular basis of inhibition of GudB by GltAB. The complex exhibits unusual oscillatory progress curves and is necessary for both planktonic growth, in glutamate-limiting conditions, and for biofilm growth, in glutamate-rich media. The regulation of a key metabolic enzyme by complexing with its counter enzyme may thus enable cell growth under fluctuating glutamate concentrations.


Assuntos
Bacillus subtilis/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Regulação Enzimológica da Expressão Gênica/fisiologia , Glutamato Desidrogenase/metabolismo , Glutamato Sintase/metabolismo , Ácido Glutâmico/biossíntese , Bacillus subtilis/genética , Proteínas de Bactérias , Glutamato Desidrogenase/genética , Glutamato Sintase/genética
11.
Eur Biophys J ; 53(4): 225-238, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38613566

RESUMO

Calibration of titration calorimeters is an ongoing problem, particularly with calorimeters with reaction vessel volumes < 10 mL in which an electrical calibration heater is positioned outside the calorimetric vessel. Consequently, a chemical reaction with a known enthalpy change must be used to accurately calibrate these calorimeters. This work proposes the use of standard solutions of potassium acid phthalate (KHP) titrated into solutions of excess sodium hydroxide (NaOH) or excess tris(hydroxymethyl)aminomethane (TRIS) as standard reactions to determine the collective accuracy of the relevant variables in a determination of the molar enthalpy change for a reaction. KHP is readily available in high purity, weighable for easy preparation of solutions with accurately known concentrations, stable in solution, not compromised by side reactions with common contaminants such as atmospheric CO2, and non-corrosive to materials used in calorimeter construction. Molar enthalpy changes for these reactions were calculated from 0 to 60 °C from reliable literature data for the pKa of KHP, the molar enthalpy change for protonation of TRIS, and the molar enthalpy change for ionization of water. The feasibility of using these reactions as enthalpic standards was tested in several calorimeters; a 50 mL CSC 4300, a 185 µL NanoITC, a 1.4 mL VP-ITC, and a TAM III with 1 mL reaction vessels. The results from the 50 mL CSC 4300, which was accurately calibrated with an electric heater, verified the accuracy of the calculated standard values for the molar enthalpy changes of the proposed reactions.


Assuntos
Calorimetria , Hidróxido de Sódio , Trometamina , Hidróxido de Sódio/química , Calibragem , Trometamina/química , Temperatura , Padrões de Referência , Termodinâmica
12.
Clin Radiol ; 79(7): e908-e915, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38649313

RESUMO

AIM: To compare the image quality of virtual noncontrast (VNC) and true noncontrast (TNC) CT images and to evaluate the clinical feasibility of VNC CT images for assessing osteochondral lesions of the talus (OLTs). MATERIALS AND METHODS: Forty-five OLT patients who underwent ankle CT arthrography (CTA) using dual-layer spectral detector CT were enrolled. Reconstruction of VNC and three-dimensional volume rendering images was performed. Afterward, image noise, the signal-to-noise ratio (SNR), and the contrast-to-noise ratio (CNR) were measured. For the subjective evaluation, two board-certified musculoskeletal radiologists [R2-1] assessed spatial resolution, overall image quality, and lesion conspicuity. The accuracy rate for OLT grading was determined in 23 patients who underwent arthroscopic surgery. RESULTS: While VNC images showed significantly less noise than TNC images, TNC images showed better SNRs and CNRs (p<.01). In the subjective analysis, TNC images showed better overall image quality (p<.001). For the 3D volume rendering images, VNC images scored significantly higher for lesion conspicuity (p<.001). The accuracy rates of CTA and CTA with VNC images for OLT grading were 79.2% and 83.3%, respectively. Regarding confidence level, when CTA and VNC images were evaluated together, the confidence level was significantly higher than that when only CTA images were evaluated (p<.001). CONCLUSION: VNC imaging can provide better confidence level of OLT grading and evaluation of the integrity of the subchondral bone plate when combined with conventional CTA without additional radiation dose to the patient. In addition, VNC images-based 3D volume rendering reconstruction would be helpful for preoperative planning in OLT patients.


Assuntos
Artrografia , Estudos de Viabilidade , Tálus , Tomografia Computadorizada por Raios X , Humanos , Tálus/diagnóstico por imagem , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X/métodos , Artrografia/métodos , Imageamento Tridimensional/métodos , Adulto Jovem , Idoso , Adolescente , Razão Sinal-Ruído , Estudos Retrospectivos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos
13.
Clin Radiol ; 79(1): e102-e111, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37863747

RESUMO

AIM: To verify the diagnostic performance of the loss of nigrosome-1 on susceptibility-weighted imaging (SWI) with compressed sensing-sensitivity encoding (CS-SENSE) and neuromelanin on neuromelanin-sensitive (NM) magnetic resonance imaging (MRI) for the diagnosis of Parkinson's disease (PD) and atypical Parkinsonism. MATERIALS AND METHODS: A total of 195 patients who underwent MRI between October 2019 and February 2020, including SWI, with or without CS-SENSE, and NM-MRI, were reviewed retrospectively. Two neuroradiologists assessed the loss of nigrosome-1 on SWI and neuromelanin on the NM-MRI. The result of N-3-fluoropropyl-2-beta-carbomethoxy-3-beta-(4-iodophenyl) nortropane positron-emission tomography (PET) was set as the reference standard. RESULTS: When CS-SENSE was applied for nigrosome-1 imaging on SWI, the non-diagnostic scan rate was lowered significantly from 19.3% (17/88) to 5.6% (6/107; p=0.004). Diagnosis of PD and atypical Parkinsonism based on the loss of nigrosome-1 on SWI and based on NM-MRI showed good diagnostic value (area under the curve [AUC] 0.821, 95% confidence interval [CI] = 0.755-0.875: AUC 0.832, 95% CI = 0.771-0.882, respectively) with a substantial inter-reader agreement (κ = 0.791 and 0.681, respectively). Combined SWI and neuromelanin had a similar discriminatory ability (AUC 0.830, 95% CI = 0.770-0.880). Similarly, the diagnosis of PD was excellent. CONCLUSIONS: CS-SENSE may add value to the diagnostic capability of nigrosome-1 on SWI to reduce the nondiagnostic scan rates. Furthermore, loss of nigrosome-1 on SWI or volume loss of neuromelanin on NM-MRI may be helpful for diagnosing PD.


Assuntos
Doença de Parkinson , Transtornos Parkinsonianos , Humanos , Doença de Parkinson/diagnóstico por imagem , Estudos Retrospectivos , Transtornos Parkinsonianos/diagnóstico , Imageamento por Ressonância Magnética/métodos
14.
Child Dev ; 95(4): e287-e304, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38456563

RESUMO

Independent decision making requires forming stable estimates of one's preferences. We assessed whether adolescents learn about their preferences through choice deliberation and whether depressive symptoms disrupt this process. Adolescents aged 11-18 (N = 214; participated 2021-22; Female: 53.9%; White/Black/Asian/Mixed/Arab or Latin American: 26/21/19/9/8%) rated multiple activities, chose between pairs of activities and re-rated those activities. As expected, overall, participants uprated chosen and downrated unchosen activities (dz = .20). This value refinement through choice was not evident in younger participants but emerged across adolescence. Contrary to our predictions, depressive symptoms were associated with greater value refinement. Despite this, more depressed adolescents reported lower value certainty and choice confidence. The cognitive processes through which choice deliberation shapes preference develop over adolescence, and are disrupted in depression.


Assuntos
Comportamento de Escolha , Depressão , Humanos , Feminino , Adolescente , Masculino , Criança , Comportamento de Escolha/fisiologia , Comportamento do Adolescente/fisiologia , Desenvolvimento do Adolescente/fisiologia
15.
Proc Natl Acad Sci U S A ; 118(16)2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33846262

RESUMO

Enzymes in multistep metabolic pathways utilize an array of regulatory mechanisms to maintain a delicate homeostasis [K. Magnuson, S. Jackowski, C. O. Rock, J. E. Cronan, Jr, Microbiol. Rev. 57, 522-542 (1993)]. Carrier proteins in particular play an essential role in shuttling substrates between appropriate enzymes in metabolic pathways. Although hypothesized [E. Ploskon et al., Chem. Biol. 17, 776-785 (2010)], allosteric regulation of substrate delivery has never before been demonstrated for any acyl carrier protein (ACP)-dependent pathway. Studying these mechanisms has remained challenging due to the transient and dynamic nature of protein-protein interactions, the vast diversity of substrates, and substrate instability [K. Finzel, D. J. Lee, M. D. Burkart, ChemBioChem 16, 528-547 (2015)]. Here we demonstrate a unique communication mechanism between the ACP and partner enzymes using solution NMR spectroscopy and molecular dynamics to elucidate allostery that is dependent on fatty acid chain length. We demonstrate that partner enzymes can allosterically distinguish between chain lengths via protein-protein interactions as structural features of substrate sequestration are translated from within the ACP four-helical bundle to the protein surface, without the need for stochastic chain flipping. These results illuminate details of cargo communication by the ACP that can serve as a foundation for engineering carrier protein-dependent pathways for specific, desired products.


Assuntos
Proteína de Transporte de Acila/metabolismo , Proteína de Transporte de Acila/ultraestrutura , Regulação Alostérica/fisiologia , Proteína de Transporte de Acila/fisiologia , Sequência de Aminoácidos , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Simulação de Acoplamento Molecular/métodos , Simulação de Dinâmica Molecular , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas/fisiologia , Mapas de Interação de Proteínas/fisiologia
16.
Skeletal Radiol ; 53(4): 629-636, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37955679

RESUMO

After emergent assessment of potentially limb-threatening injuries in knee dislocation or multi-ligament knee injury patients, magnetic resonance imaging is necessary to visualize ligamentous structures and plan for soft tissue repair. However, the application of a knee-spanning external fixator may introduce artifact and reduce overall image quality, which can limit the evaluation of soft tissue injury. As a result, the utility of MRI in the context of a knee-spanning external fixator has been called into question. Signal-to-noise ratio, contrast-to-noise ratio, and qualitative scales have been used to assess image quality of MRI in the context of a knee-spanning external fixator. Despite the potential for artifact, studies have demonstrated that useful diagnostic information may be obtained from MRI in the presence of an external fixator. This review examines the general principles of anatomical assessment, magnetic field strength, device composition and design, radiofrequency coil use, and MRI sequences and artifact reduction as they pertain to MRI in the presence of a knee-spanning external fixator.


Assuntos
Luxação do Joelho , Articulação do Joelho , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Joelho , Fixadores Externos , Luxação do Joelho/cirurgia , Imageamento por Ressonância Magnética/métodos
17.
Skeletal Radiol ; 53(3): 525-536, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37695343

RESUMO

OBJECTIVE: Concerns regarding patient safety and image quality have made the use of knee-spanning external fixators in MRI a challenging clinical scenario. The purpose of our study was to poll practicing musculoskeletal radiologists on their personal experiences regarding the use of knee-spanning external fixators in MRI in an effort to consolidate practice trends for the radiologists' benefit. METHODS: A 27-item survey was created to address the institutional use, safety, adverse events, quality, and perspectives of the radiologist related to MRI of an externally fixated knee. The survey was distributed to 1739 members of the Society of Skeletal Radiology. RESULTS: A total of 72 members of the Society of Skeletal Radiology completed the survey. Most notably, 40 of 72 (55.56%) respondents are permitted to place a knee-spanning external fixator inside the MR bore at their institution, while19 of 72 (26.39%) respondents are not permitted to do so. Fourteen of 32 (43.75%) respondents have institutional guidelines for safely performing an MRI of an externally fixated knee. Twenty-five of 32 (78.13%) respondents are comfortable permitting an MRI of an externally fixated knee. CONCLUSION: We found a general lack of consensus regarding the decision to scan a patient with a knee-spanning external fixator in MRI. Many institutions lack safety guidelines, and providers rely upon a heterogeneous breadth of resources for safety information. A re-examination of the FDA device labeling nomenclature and expectations of the individual manufacturers may be needed to bridge this gap and help direct management decisions placed upon the provider.


Assuntos
Segurança do Paciente , Radiologia , Humanos , Política Organizacional , Fixadores Externos , Imageamento por Ressonância Magnética/métodos , Inquéritos e Questionários
18.
Subst Use Misuse ; : 1-5, 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-39077814

RESUMO

OBJECTIVE: Intergenerational studies have identified relations between adolescents' and their future offspring's cannabis and alcohol use, but rarely have examined the association for other illicit drug use. Given the low prevalence of such use in community populations, we pooled data from three prospective intergenerational studies to test this link. METHOD: Participants were 1,060 children of 937 parents who had been repeatedly assessed since early adolescence. Children and parents reported on their use of cocaine, stimulants, hallucinogens, sedatives/tranquilizers, and opiates/narcotics from ages 10 to 18 years. Intergenerational similarities in any versus no use of these drugs were formally modeled using logistic regression. Patterns also were descriptively analyzed. RESULTS: Parent illicit substance use was associated with significantly higher odds of child use (adjusted odds ratio [95% confidence interval] = 2.682 [1.328-5.416], p = 0.006). However, intergenerational continuity was modest; 87% of children whose parent used illicit drugs in adolescence did not use such drugs, and 77% of parents of children who used illicit drugs had not themselves used these drugs during adolescence. CONCLUSIONS: The use of illicit substances by parents during their teenage years poses a risk for their offspring's similar behaviors. However, the discontinuity of these behaviors across generations implies children are largely resilient to or protected from this risk, and conversely that other aspects of parents' and children's experiences or characteristics may be more powerful risks for children's illicit drug use than this transgenerational influence.


(a) Parents' use of illicit drugs during adolescence significantly increased risk that their adolescent children would use such drugs. (b) However, most parents who used illicit drugs did not have children who used illicit drugs, and conversely, the majority of adolescents who used illicit drugs did not have parents who had used such drugs in their adolescence.

19.
Tech Coloproctol ; 28(1): 25, 2024 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-38231341

RESUMO

BACKGROUND: Total mesorectal excision using conventional straight fixed devices may be technically difficult because of the narrow and concave pelvis. Several laparoscopic articulating tools have been introduced as an alternative to robotic systems. The aim of this study was to compare perioperative outcomes between laparoscopic low anterior resection using ArtiSential® and robot-assisted surgery for rectal cancer. METHODS: This retrospective study included 682 patients who underwent laparoscopic or robotic low anterior resection  for rectal cancer from September 2018 to December 2021. Among them, 82 underwent laparoscopic surgery using ArtiSential® (group A) and 201 underwent robotic surgery (group B). A total of 73 [group A; 66.37 ± 11.62; group B 65.79 ± 11.34] patients were selected for each group using a propensity score matching analysis. RESULTS: There was no significant difference in the baseline characteristics between group A and B. Mean operative time was longer in group B than A (163.5 ± 61.9 vs 250.1 ± 77.6 min, p < 0.001). Mean length of hospital stay was not significantly different between the two groups (6.2 ± 4.7 vs 6.7 ± 6.1 days, p = 0.617). Postoperative complications, reoperation, and readmission within 30 days after surgery were similar between the two groups. Pathological findings revealed that the circumferential resection margins were above 10 mm in both groups (11.00 ± 7.47 vs 10.17 ± 6.25 mm, p = 0.960). At least 12 lymph nodes were sufficiently harvested, with no significant difference in the number harvested between the groups (20.5 ± 9.9 vs 19.7 ± 7.3, p = 0.753). CONCLUSIONS: Laparoscopic low anterior resection using ArtiSential® can achieve acceptable clinical and oncologic outcomes. ArtiSential®, a multi-joint and articulating device, may serve a feasible alternative approach to robotic surgery in rectal cancer.


Assuntos
Laparoscopia , Neoplasias Retais , Procedimentos Cirúrgicos Robóticos , Humanos , Pontuação de Propensão , Estudos Retrospectivos , Neoplasias Retais/cirurgia
20.
Int J Phytoremediation ; 26(3): 324-338, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37545130

RESUMO

In this investigation, microwave irradiation assisted by ZnCl2 was used to transform pineapple crown (PN) waste into mesoporous activated carbon (PNAC). Complementary techniques were employed to examine the physicochemical characteristics of PNAC, including BET, FTIR, SEM-EDX, XRD, and pH at the point-of-zero-charge (pHpzc). PNAC is mesoporous adsorbent with a surface area of 1070 m2/g. The statistical optimization for the adsorption process of two model cationic dyes (methylene blue: MB and, crystal violet: CV) was conducted using the response surface methodology-Box-Behnken design (RSM-BBD). The parameters include solution pH (4-10), contact time (2-12) min, and PNAC dosage (0.02-0.1 g/100 mL). The Freundlich and Langmuir models adequately described the dye adsorption isotherm results for the MB and CV systems, whereas the pseudo-second order kinetic model accounted for the time dependent adsorption results. The maximum adsorption capacity (qmax) for PNAC with the two tested dyes are listed: 263.9 mg/g for CV and 274.8 mg/g for MB. The unique adsorption mechanism of MB and CV dyes by PNAC implicates multiple contributions to the adsorption process such as pore filling, electrostatic forces, H-bonding, and π-π interactions. This study illustrates the possibility of transforming PN into activated carbon (PNAC) with the potential to remove two cationic dyes from aqueous media.


The novelty of this research work stems from the conversion of pineapple (Ananas comosus) crown wastes with no monetary value into an efficient activated carbon adsorbent with relatively high surface area. Furthermore, a fast and convenient microwave assisted ZnCl2 activation method was applied for producing the activated carbon (AC). The effectiveness of the produced AC was tested for the removal of two different cationic dyes: crystal violet (CV) and methylene blue (MB). A statistical optimization that employs a response surface methodology with the Box-Behnken design was employed to optimize the adsorption variables for the optimal dye removal. Moreover, the dye adsorption kinetics and thermodynamics, equilibrium isotherms, and the details of the adsorption process were reported herein.


Assuntos
Ananas , Poluentes Químicos da Água , Corantes/química , Azul de Metileno/análise , Azul de Metileno/química , Carvão Vegetal/química , Violeta Genciana , Adsorção , Micro-Ondas , Biodegradação Ambiental , Cinética , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio
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