RESUMO
Dynamic PET allows quantification of physiological parameters through tracer kinetic modeling. For dynamic imaging of brain or head and neck cancer on conventional PET scanners with a short axial field of view, the image-derived input function (ID-IF) from intracranial blood vessels such as the carotid artery (CA) suffers from severe partial volume effects. Alternatively, optimization-derived input function (OD-IF) by the simultaneous estimation (SIME) method does not rely on an ID-IF but derives the input function directly from the data. However, the optimization problem is often highly ill-posed. We proposed a new method that combines the ideas of OD-IF and ID-IF together through a kernel framework. While evaluation of such a method is challenging in human subjects, we used the uEXPLORER total-body PET system that covers major blood pools to provide a reference for validation. METHODS: The conventional SIME approach estimates an input function using a joint estimation together with kinetic parameters by fitting time activity curves from multiple regions of interests (ROIs). The input function is commonly parameterized with a highly nonlinear model which is difficult to estimate. The proposed kernel SIME method exploits the CA ID-IF as a priori information via a kernel representation to stabilize the SIME approach. The unknown parameters are linear and thus easier to estimate. The proposed method was evaluated using 18F-fluorodeoxyglucose studies with both computer simulations and 20 human-subject scans acquired on the uEXPLORER scanner. The effect of the number of ROIs on kernel SIME was also explored. RESULTS: The estimated OD-IF by kernel SIME showed a good match with the reference input function and provided more accurate estimation of kinetic parameters for both simulation and human-subject data. The kernel SIME led to the highest correlation coefficient (R = 0.97) and the lowest mean absolute error (MAE = 10.5 %) compared to using the CA ID-IF (R = 0.86, MAE = 108.2 %) and conventional SIME (R = 0.57, MAE = 78.7 %) in the human-subject evaluation. Adding more ROIs improved the overall performance of the kernel SIME method. CONCLUSION: The proposed kernel SIME method shows promise to provide an accurate estimation of the blood input function and kinetic parameters for brain PET parametric imaging.
Assuntos
Encéfalo , Tomografia por Emissão de Pósitrons , Humanos , Tomografia por Emissão de Pósitrons/métodos , Tomografia por Emissão de Pósitrons/normas , Encéfalo/diagnóstico por imagem , Imagem Corporal Total/métodos , Processamento de Imagem Assistida por Computador/métodos , AlgoritmosRESUMO
Novel Gram-positive, catalase-negative, α-haemolytic cocci were isolated from breast milk samples of healthy mothers living in Hanoi, Vietnam. The 16S rRNA gene sequences of these strains varied by 0-2 nucleotide polymorphisms. The 16S rRNA gene sequence of one strain, designated as BME SL 6.1T, showed the highest similarity to those of Streptococcus salivarius NCTC 8618T (99.4â%), Streptococcus vestibularis ATCC 49124T (99.4â%), and Streptococcus thermophilus ATCC 19258T (99.3â%) in the salivarius group. Whole genome sequencing was performed on three selected strains. Phylogeny based on 631 core genes clustered the three strains into the salivarius group, and the strains were clearly distinct from the other species in this group. The average nucleotide identity (ANI) value of strain BME SL 6.1T exhibited the highest identity with S. salivarius NCTC 8618T (88.4â%), followed by S. vestibularis ATCC 49124T (88.3â%) and S. thermophilus ATCC 19258T (87.4â%). The ANI and digital DNA-DNA hybridization values between strain BME SL 6.1T and other species were below the cut-off value (95 and 70â%, respectively), indicating that it represents a novel species of the genus Streptococcus. The strains were able to produce α-galactosidase and acid from raffinose and melibiose. Therefore, we propose to assign the strains to a new species of the genus Streptococcus as Streptococcus raffinosi sp. nov. The type strain is BME SL 6.1T (=VTCC 12812T=NBRC 116368T).
Assuntos
Técnicas de Tipagem Bacteriana , DNA Bacteriano , Leite Humano , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA , Streptococcus , RNA Ribossômico 16S/genética , Humanos , Feminino , DNA Bacteriano/genética , Leite Humano/microbiologia , Streptococcus/genética , Streptococcus/isolamento & purificação , Streptococcus/classificação , Vietnã , Sequenciamento Completo do GenomaRESUMO
Within 8 months, 3 children from 1 family in northern Vietnam died from melioidosis. Burkholderia pseudomallei of the same sequence type, 541, was isolated from clinical samples, borehole water, and garden and rice field soil. Boreholes should be properly constructed and maintained to avoid B. pseudomallei contamination.
Assuntos
Burkholderia pseudomallei , Melioidose , Burkholderia pseudomallei/genética , Criança , Humanos , Melioidose/epidemiologia , Microbiologia do Solo , Vietnã/epidemiologia , ÁguaRESUMO
In recent years, attempts have been made to develop a thermophilic composting process for organic sludge to produce ammonia gas for high value-added algal production. However, the hydrolysis of non-dissolved organic nitrogen in sludge is a bottleneck for ammonia conversion. The aim of this study was to identify enzymes that enhance sludge hydrolysis in a thermophilic composting system for ammonia recovery from shrimp pond sludge. This was achieved by screening useful enzymes to degrade non-dissolved nitrogen and subsequently investigating their effectiveness in lab-scale composting systems. Among the four hydrolytic enzyme classes assessed (lysozyme, protease, phospholipase, and collagenase), proteases from Streptomyces griseus were the most effective at hydrolysing non-dissolved nitrogen in the sludge. After composting sludge pre-treated with proteases, the final amount of non-dissolved nitrogen was 46.2% of the total N in the control sample and 22.3% of the total N in the protease sample, thus increasing the ammonia (gaseous and in-compost) conversion efficiency from 41.5% to 56.4% of the total N. The decrease in non-dissolved nitrogen was greater in the protease sample than in the control sample during the pre-treatment period, and no difference was observed during the subsequent composting period. These results suggest that Streptomyces proteases hydrolyse the organic nitrogen fraction, which cannot be degraded by the bacterial community in the compost. Functional potential analysis of the bacterial community using PICRUSt2 suggested that 4 (EC:3.4.21.80, EC:3.4.21.81, EC:3.4.21.82, and EC:3.4.24.77) out of 13 endopeptidase genes in S. griseus were largely absent in the compost bacterial community and that they play a key role in the hydrolysis of non-dissolved nitrogen. This is the first study to identify the enzymes that enhance the hydrolysis of shrimp pond sludge and to show that the thermophilic bacterial community involved in composting has a low ability to secrete these enzymes.
Assuntos
Compostagem , Amônia/análise , Nitrogênio/análise , Lagoas/análise , Esgotos , SoloRESUMO
RATIONALE: Conventional 3-dimensional (3D) printing techniques cannot produce structures of the size at which individual cells interact. OBJECTIVE: Here, we used multiphoton-excited 3D printing to generate a native-like extracellular matrix scaffold with submicron resolution and then seeded the scaffold with cardiomyocytes, smooth muscle cells, and endothelial cells that had been differentiated from human-induced pluripotent stem cells to generate a human-induced pluripotent stem cell-derived cardiac muscle patch (hCMP), which was subsequently evaluated in a murine model of myocardial infarction. METHODS AND RESULTS: The scaffold was seeded with ≈50 000 human-induced pluripotent stem cell-derived cardiomyocytes, smooth muscle cells, and endothelial cells (in a 2:1:1 ratio) to generate the hCMP, which began generating calcium transients and beating synchronously within 1 day of seeding; the speeds of contraction and relaxation and the peak amplitudes of the calcium transients increased significantly over the next 7 days. When tested in mice with surgically induced myocardial infarction, measurements of cardiac function, infarct size, apoptosis, both vascular and arteriole density, and cell proliferation at week 4 after treatment were significantly better in animals treated with the hCMPs than in animals treated with cell-free scaffolds, and the rate of cell engraftment in hCMP-treated animals was 24.5% at week 1 and 11.2% at week 4. CONCLUSIONS: Thus, the novel multiphoton-excited 3D printing technique produces extracellular matrix-based scaffolds with exceptional resolution and fidelity, and hCMPs fabricated with these scaffolds may significantly improve recovery from ischemic myocardial injury.
Assuntos
Comunicação Celular , Diferenciação Celular , Células Endoteliais/metabolismo , Matriz Extracelular/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Miócitos Cardíacos/metabolismo , Miócitos de Músculo Liso/metabolismo , Impressão Tridimensional , Engenharia Tecidual/métodos , Alicerces Teciduais , Animais , Células Cultivadas , Técnicas de Cocultura , Modelos Animais de Doenças , Células Endoteliais/patologia , Células Endoteliais/transplante , Matriz Extracelular/ultraestrutura , Frequência Cardíaca , Humanos , Células-Tronco Pluripotentes Induzidas/transplante , Camundongos Endogâmicos NOD , Camundongos SCID , Contração Miocárdica , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Infarto do Miocárdio/cirurgia , Miócitos Cardíacos/patologia , Miócitos Cardíacos/transplante , Miócitos de Músculo Liso/patologia , Miócitos de Músculo Liso/transplante , Fenótipo , Recuperação de Função Fisiológica , Regeneração , Fatores de Tempo , Transfecção , Função Ventricular EsquerdaRESUMO
BACKGROUND: Brainstem encephalitis is a serious complication of hand foot and mouth disease (HFMD) in children. Autonomic nervous system (ANS) dysregulation and hypertension may occur, sometimes progressing to cardiopulmonary failure and death. Vietnamese national guidelines recommend use of milrinone if ANS dysregulation with Stage 2 hypertension develops. We wished to investigate whether magnesium sulfate (MgSO4) improved outcomes in children with HFMD if used earlier in the evolution of the ANS dysregulation (Stage 1 hypertension). METHODS: During a regional epidemic we conducted a randomized, double-blind, placebo-controlled trial of MgSO4 in children with HFMD, ANS dysregulation and Stage 1 hypertension, at the Hospital for Tropical Diseases in Ho Chi Minh city. Study participants received an infusion of MgSO4 or matched placebo for 72 h. We also reviewed data from non-trial HFMD patients in whom milrinone failed to control hypertension, some of whom received MgSO4 as second line therapy. The primary outcome for both analyses was a composite of disease progression within 72 h - addition of milrinone (trial participants only), need for ventilation, shock, or death. RESULTS: Between June 2014 and September 2016, 14 and 12 participants received MgSO4 or placebo respectively, before the trial was stopped due to futility. Among 45 non-trial cases with poorly controlled hypertension despite high-dose milrinone, 33 received MgSO4 while 12 did not. There were no statistically significant differences in the composite outcome between the MgSO4 and the placebo/control groups in either study (adjusted relative risk (95%CI) of [6/14 (43%) vs. 6/12 (50%)], 0.84 (0.37, 1.92), p = 0.682 in the trial and [1/33 (3%) vs. 2/12 (17%)], 0.16 (0.01, 1.79), p = 0.132 in the observational cohort). The incidence of adverse events was similar between the groups. Potentially toxic magnesium levels occurred very rarely with the infusion regime used. CONCLUSION: Although we could not demonstrate efficacy in these studies, there were no safety signals associated with use of 30-50 mg/kg/hr. MgSO4 in severe HFMD. Intermittent outbreaks of HFMD are likely to continue across the region, and an adequately powered trial is still needed to evaluate use of MgSO4 in controlling hypertension in severe HFMD, potentially involving a higher dose regimen. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01940250 (Registered 22 AUG 2013). Trial sponsor: University of Oxford.
Assuntos
Doenças do Sistema Nervoso Autônomo/tratamento farmacológico , Doença de Mão, Pé e Boca/tratamento farmacológico , Sulfato de Magnésio/uso terapêutico , Animais , Sistema Nervoso Autônomo/efeitos dos fármacos , Sistema Nervoso Autônomo/fisiologia , Doenças do Sistema Nervoso Autônomo/etiologia , Criança , Pré-Escolar , Estudos de Coortes , Progressão da Doença , Método Duplo-Cego , Feminino , Doença de Mão, Pé e Boca/complicações , Doença de Mão, Pé e Boca/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Humanos , Lactente , Sulfato de Magnésio/efeitos adversos , Masculino , PlacebosRESUMO
BACKGROUND: Although hepatitis C virus (HCV) infection is curable, treatment of difficult to access populations (DTAP) presents unique challenges. Project ECHO (PE) (Extension for Community Healthcare Outcomes) is a telementoring programme adopted to support clinicians treating DTAP. AIMS: To determine if the PE model supports primary care clinicians treating HCV and to compare cohort of PE patients with those in a tertiary liver clinic (TLC). METHODS: Weekly PE group video conferences were conducted. Clinical information, laboratory indices, psychosocial elements and treatment outcomes, including sustained virological response (SVR) data were recorded in the first 100 consecutive cases and retrospectively compared to 100 consecutive patients seen at a TLC from July 2016 to April 2017. RESULTS: Some patient characteristics were similar between PE and TLC: gender (72% vs 75% male; P = 0.23), median age (45 vs 50; P = 0.344) and the proportion of treatment naïve patients (95.0% vs 90.9%). Treatment for HCV was commenced in 78% of the PE patients and 81% of the TLC patients; 67/68 of the TLC patients and 60/61 PE patients with virological follow up who completed treatment and attended follow up have confirmed SVR. PE patients are more likely to have ongoing substance use (44% vs 17% P < 0.001), be active intravenous drug users (32% vs 17%; P < 0.001) and polysubstance abusers (26% vs 7%; P < 0.001) and were more likely to be taking opioid substitution therapy (74% vs 20%; P < 0.001). Indigenous patients were three times more greatly represented in PE (15% vs 5%; P = 0.018). CONCLUSION: PE is an effective model to support primary healthcare providers treating HCV in DTAP with similar rates of treatment uptake and SVR compared to patients in TLC.
Assuntos
Antivirais/uso terapêutico , Usuários de Drogas , Hepatite C Crônica/tratamento farmacológico , Abuso de Substâncias por Via Intravenosa/complicações , Telemedicina , Austrália , Serviços de Saúde Comunitária/métodos , Feminino , Hepatite C Crônica/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Tratamento de Substituição de Opiáceos , Atenção Primária à Saúde , Estudos Retrospectivos , Resposta Viral Sustentada , Populações VulneráveisRESUMO
It is generally considered that if an RNA World ever existed that it would be driven by an RNA capable of RNA replication. Whether such a catalytic RNA could emerge in an RNA World or not, there would need to be prior routes to increasing complexity in order to produce it. It is hypothesized here that increasing sequence variety, if not complexity, can in fact readily emerge in response to a dynamic equilibrium between synthesis and degradation. A model system in which T4 RNA ligase catalyzes synthesis and Benzonase catalyzes degradation was constructed. An initial 20-mer served as a seed and was subjected to 180 min of simultaneous ligation and degradation. The seed RNA rapidly disappeared and was replaced by an increasing number and variety of both larger and smaller variants. Variants of 40-80 residues were consistently seen, typically representing 2-4% of the unique sequences. In a second experiment with four individual 9-mers, numerous variants were again produced. These included variants of the individual 9-mers as well as sequences that contained sequence segments from two or more 9-mers. In both cases, the RNA products lack large numbers of point mutations but instead incorporate additions and subtractions of fragments of the original RNAs. The system demonstrates that if such equilibrium were established in a prebiotic world it would result in significant exploration of RNA sequence space and likely increased complexity. It remains to be seen if the variety of products produced is affected by the presence of small peptide oligomers.
Assuntos
RNA Polimerase Dependente de RNA/metabolismo , RNA/genética , Composição de Bases/genética , Sequência de Bases , Nucleotídeos/genéticaRESUMO
The highly conserved peptidyl transferase center (PTC) of the ribosome contains an RNA pore that serves as the entrance to the exit tunnel. Analysis of available ribosome crystal structures has revealed the presence of multiple additional well-defined pores of comparable size in the ribosomal (rRNA) RNAs. These typically have dimensions of 1-2 nm, with a total area of â¼100 Å(2) or more, and most are associated with one or more ribosomal proteins. The PTC example and the other rRNA pores result from the packing of helices. However, in the non-PTC cases the nitrogenous bases do not protrude into the pore, thereby limiting the potential for hydrogen bonding within the pore. Instead, it is the RNA backbone that largely defines the pore likely resulting in a negatively charged environment. In many but not all cases, ribosomal proteins are associated with the pores to a greater or lesser extent. With the exception of the PTC case, the large subunit pores are not found in what are thought to be the evolutionarily oldest regions of the 23S rRNA. The unusual nature of the PTC pore may reflect a history of being created by hybridization between two or more RNAs early in evolution rather than simple folding of a single RNA. An initial survey of nonribosomal RNA crystal structures revealed additional pores, thereby showing that they are likely a general feature of RNA tertiary structure.
Assuntos
Nanoestruturas/química , Peptidil Transferases/metabolismo , RNA Ribossômico 16S/química , RNA Ribossômico 23S/química , Proteínas Ribossômicas/metabolismo , Ribossomos/metabolismo , Sítios de Ligação , Modelos Moleculares , Conformação de Ácido Nucleico , Peptidil Transferases/química , RNA Ribossômico 16S/metabolismo , Proteínas Ribossômicas/química , Ribossomos/química , Thermus thermophilus/genética , Thermus thermophilus/metabolismoRESUMO
Chromatin readers decipher the functional readouts of histone modifications by recruiting specific effector complexes for subsequent epigenetic reprogramming. The LSD1 (also known as KDM1A) histone demethylase complex modifies chromatin and represses transcription in part by catalyzing demethylation of dimethylated histone H3 lysine 4 (H3K4me2), a mark for active transcription. However, none of its currently known subunits recognizes methylated histones. The Snai1 family transcription factors are central drivers of epithelial-to-mesenchymal transition (EMT) by which epithelial cells acquire enhanced invasiveness. Snai1-mediated transcriptional repression of epithelial genes depends on its recruitment of the LSD1 complex and ensuing demethylation of H3K4me2 at its target genes. Through biochemical purification, we identified the MBT domain-containing protein SFMBT1 as a novel component of the LSD1 complex associated with Snai1. Unlike other mammalian MBT domain proteins characterized to date that selectively recognize mono- and dimethylated lysines, SFMBT1 binds di- and trimethyl H3K4, both of which are enriched at active promoters. We show that SFMBT1 is essential for Snai1-dependent recruitment of LSD1 to chromatin, demethylation of H3K4me2, transcriptional repression of epithelial markers, and induction of EMT by TGFß. Carcinogenic metal nickel is a widespread environmental and occupational pollutant. Nickel alters gene expression and induces EMT. We demonstrate the nickel-initiated effects are dependent on LSD1-SFMBT1-mediated chromatin modification. Furthermore, in human cancer, expression of SFMBT1 is associated with mesenchymal markers and unfavorable prognosis. These results highlight a critical role of SFMBT1 in epigenetic regulation, EMT, and cancer.
Assuntos
Cromatina/metabolismo , Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal , Histona Desmetilases/metabolismo , Histonas/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Proteínas Repressoras/metabolismo , Carcinógenos/farmacologia , Cromatina/genética , Cromatina/patologia , Células Epiteliais/patologia , Células HEK293 , Histona Desmetilases/genética , Histonas/genética , Humanos , Metilação , Proteínas de Neoplasias/genética , Neoplasias/genética , Neoplasias/patologia , Níquel/efeitos adversos , Níquel/farmacologia , Proteínas Repressoras/genética , Fatores de Transcrição da Família Snail , Oligoelementos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
BACKGROUND: Perchlorate contamination has been detected in both ground water and drinking water. An attractive treatment option is the use of ion-exchange to remove and concentrate perchlorate in brine. Biological treatment can subsequently remove the perchlorate from the brine. When nitrate is present, it will also be concentrated in the brine and must also be removed by biological treatment. The primary objective was to obtain an in-depth characterization of the microbial populations of two salt-tolerant cultures each of which is capable of metabolizing perchlorate. The cultures were derived from a single ancestral culture and have been maintained in the laboratory for more than 10 years. One culture was fed perchlorate only, while the other was fed both perchlorate and nitrate. RESULTS: A metagenomic characterization was performed using Illumina DNA sequencing technology, and the 16S rDNA of several pure strains isolated from the mixed cultures were sequenced. In the absence of nitrate, members of the Rhodobacteraceae constituted the prevailing taxonomic group. Second in abundance were the Rhodocyclaceae. In the nitrate fed culture, the Rhodobacteraceae are essentially absent. They are replaced by a major expansion of the Rhodocyclaceae and the emergence of the Alteromonadaceae as a significant community member. Gene sequences exhibiting significant homology to known perchlorate and nitrate reduction enzymes were found in both cultures. CONCLUSIONS: The structure of the two microbial ecosystems of interest has been established and some representative strains obtained in pure culture. The results illustrate that under favorable conditions a group of organisms can readily dominate an ecosystem and yet be effectively eliminated when their advantage is lost. Almost all known perchlorate-reducing organisms can also effectively reduce nitrate. This is certainly not the case for the Rhodobacteraceae that were found to dominate in the absence of nitrate, but effectively disappeared in its presence. This study is significant in that it reveals the existence of a novel group of organisms that play a role in the reduction of perchlorate under saline conditions. These Rhodobacteraceae especially, as well as other organisms present in these communities may be a promising source of unique salt-tolerant enzymes for perchlorate reduction.
Assuntos
Reatores Biológicos/microbiologia , Nitratos/metabolismo , Percloratos/metabolismo , Rhodobacteraceae/metabolismo , Rhodocyclaceae/metabolismo , Cloreto de Sódio/metabolismo , Sequência de Bases , Biodegradação Ambiental , Troca Iônica , Metagenoma/genética , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Rhodobacteraceae/genética , Rhodocyclaceae/genética , Sais/metabolismoRESUMO
Recently, researchers have uncovered a correlation between loneliness and both the development and management of diabetes. Nevertheless, previous studies employing an unvalidated loneliness questionnaire impair result accuracy. Furthermore, this aspect has not been researched in the Japanese population. Therefore, this cross-sectional study analyzed data from the Kanagawa prospective "ME-BYO" Cohort Study (ME-BYO cohort) to investigate the correlation between loneliness, as measured by 20 items on the UCLA Loneliness Scale, and blood glucose levels. A total of 666 participants were included in the analysis, with a mean age of 54.1 years and a mean BMI of 23 kg/m2. Half of the participants had obtained an education level beyond high school. The mean household income and physical activity level were reported as 6.83 million Japanese yen and 12.3 METs-h/day, respectively. Model 1 of the linear regression analysis determined that there was no significant association between the loneliness scale and HbA1c (p = 0.512). After adjusting for age, gender, BMI (model 2), sitting time, physical activity level (model 3), housemates, household income, and final education (model 4), and controlling for social support, quality of life, and depression (model 5), the results showed no significant association, with a p-value of 0.823, 0.791, 0.792, and 0.816, respectively. Thus, the study found no link between loneliness and HbA1c in the high SES population. This finding contradicts previous results and may be attributed to the impact of population characteristics, SES status, or genetic backgrounds.
Assuntos
Glicemia , Solidão , Humanos , Solidão/psicologia , Masculino , Feminino , Estudos Transversais , Pessoa de Meia-Idade , Japão , Glicemia/análise , Glicemia/metabolismo , Adulto , Idoso , Inquéritos e Questionários , Estudos Prospectivos , Hemoglobinas Glicadas/análise , Hemoglobinas Glicadas/metabolismo , Exercício Físico/psicologia , População do Leste AsiáticoRESUMO
Two previously unreported xanthones, xanthoschomes A and B (1 and 2), along with six known xanthones, α-mangostin (3), ß-mangostin (4), γ-mangostin (5), garcinone C (6), 2-(γ,γ-dimethylallyl)-1,7-dihydroxy-3-methoxyxanthone (7), and dulxanthone D (8), have been isolated from the fruits of Vietnamese Garcinia schomburgkiana. The structures of all isolated compounds were fully characterised using spectroscopic data and comparison with the previous literature. All isolated compounds were evaluated for their in vitro α-glucosidase inhibitory activity. Compounds 1-8 demonstrated effective α-glucosidase inhibition, with the IC50 ranging from 2.91 to 26.0 µM, outperforming the standard acarbose (IC50 179 µM). Among these isolated compounds, compound 8 exhibited the highest inhibitory activity against α-glucosidase, with an IC50 value of 2.91 µM.
RESUMO
Two previously unreported isoflavonoids, placoisoflavones A and B (1 and 2), along with five known compounds, calopogonium isoflavone B (3), jamaicin (4), 6-methoxycalopogonium isoflavone A (5), vestitol (6), and caviunin (7) have been isolated from the stems of Placolobium vietnamense N.D.Khôi & Yakovlev. The structures of all isolated compounds were fully characterized using spectroscopic data and comparison with the previous literature. The cytotoxicity of all isolated compounds was evaluated against HepG2 cell line, and compound 1 showed the most potent cytotoxicity with an IC50 value of 8.0 µM.
Assuntos
Antineoplásicos , Fabaceae , Flavonas , Isoflavonas , Estrutura Molecular , Isoflavonas/farmacologia , Isoflavonas/química , Fabaceae/químicaRESUMO
Conjugated polymer nanoparticles (CPNs or Pdots) have become increasingly popular fluorophores for multimodal applications that combine imaging with phototherapeutic effects. Reports of CPNs in photodynamic therapy applications typically focus on their ability to generate singlet oxygen. Alternatively, CPN excited states can interact with oxygen to form superoxide radical anion and a CPN-based hole polaron, both of which can have deleterious effects on fluorescence properties. Here, we demonstrate that CPNs prepared from the common conjugated polymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo-{2,1',3}-thiadiazole)] (PFBT, also known as F8BT) generate superoxide upon irradiation. We use the same CPNs to detect superoxide by doping them with a superoxide-responsive hydrocyanine dye developed by Murthy and co-workers. Superoxide induces off-to-on fluorescence switching by converting quenching hydrocyanine dyes to fluorescent cyanine dyes that act as fluorescence resonance energy transfer (FRET) acceptors for PFBT chromophores. Amplified FRET from the multichromophoric CPNs yields fluorescence signal intensities that are nearly 50 times greater than when the dye is excited directly or over 100 times greater when signal readout is from the CPN channel. The dye loading level governs the maximum amount of superoxide that induces a change in fluorescence properties and also influences the rate of superoxide generation by furnishing competitive excited state deactivation pathways. These results suggest that CPNs can be used to deliver superoxide in applications in which it is desirable and provide a caution for fluorescence-based CPN applications in which superoxide can damage fluorophores.
RESUMO
Blood-brain barrier (BBB) disruption is involved in the pathogenesis and progression of many neurological and systemic diseases. Non-invasive assessment of BBB permeability in humans has mainly been performed with dynamic contrast-enhanced magnetic resonance imaging, evaluating the BBB as a structural barrier. Here, we developed a novel non-invasive positron emission tomography (PET) method in humans to measure the BBB permeability of molecular radiotracers that cross the BBB through different transport mechanisms. Our method uses high-temporal resolution dynamic imaging and kinetic modeling to jointly estimate cerebral blood flow and tracer-specific BBB transport rate from a single dynamic PET scan and measure the molecular permeability-surface area (PS) product of the radiotracer. We show our method can resolve BBB PS across three PET radiotracers with greatly differing permeabilities, measure reductions in BBB PS of 18F-fluorodeoxyglucose (FDG) in healthy aging, and demonstrate a possible brain-body association between decreased FDG BBB PS in patients with metabolic dysfunction-associated steatotic liver inflammation. Our method opens new directions to efficiently study the molecular permeability of the human BBB in vivo using the large catalogue of available molecular PET tracers.
RESUMO
BACKGROUND: RECOVER is a randomized sham-controlled trial of vagus nerve stimulation and the largest such trial conducted with a psychiatric neuromodulation intervention. OBJECTIVE: To describe pre-implantation baseline clinical characteristics and treatment history of patients with unipolar, major depressive disorder (MDD), overall and as a function of exposure to interventional psychiatric treatments (INTs), including electroconvulsive therapy, transcranial magnetic stimulation, and esketamine. METHODS: Medical, psychiatric, and treatment records were reviewed by study investigators and an independent Study Eligibility Committee prior to study qualification. Clinical characteristics and treatment history (using Antidepressant Treatment History [Short] Form) were compared in those qualified (N = 493) versus not qualified (N = 228) for RECOVER, and among the qualified group as a function of exposure to INTs during the current major depressive episode (MDE). RESULTS: Unipolar MDD patients who qualified for RECOVER had marked TRD (median of 11.0 lifetime failed antidepressant treatments), severe disability (median WHODAS score of 50.0), and high rate of baseline suicidality (77% suicidal ideation, 40% previous suicide attempts). Overall, 71% had received at least one INT. Compared to the no INT group, INT recipients were younger and more severely depressed (QIDS-C, QIDS-SR), had greater suicidal ideation, earlier diagnosis of MDD, and failed more antidepressant medication trials. CONCLUSIONS: RECOVER-qualified unipolar patients had marked TRD and marked treatment resistance with most failing one or more prior INTs. Treatment with ≥1 INTs in the current MDE was associated with earlier age of MDD onset, more severe clinical presentation, and greater treatment resistance relative to patients without a history of INT. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT03887715.
Assuntos
Transtorno Depressivo Maior , Transtorno Depressivo Resistente a Tratamento , Estimulação Magnética Transcraniana , Humanos , Masculino , Feminino , Transtorno Depressivo Maior/terapia , Pessoa de Meia-Idade , Adulto , Transtorno Depressivo Resistente a Tratamento/terapia , Eletroconvulsoterapia , Estimulação do Nervo Vago , Antidepressivos/uso terapêutico , Ketamina , Resultado do TratamentoRESUMO
The US Food and Drug Administration (FDA) guidance has recommended several model-based predictions to determine potential drug-drug interactions (DDIs) mediated by cytochrome P450 (CYP) induction. In particular, the ratio of substrate area under the plasma concentration-time curve (AUCR) under and not under the effect of inducers is predicted by the Michaelis-Menten (MM) model, where the MM constant ( K m ) of a drug is implicitly assumed to be sufficiently higher than the concentration of CYP enzymes that metabolize the drug ( E T ) in both the liver and small intestine. Furthermore, the fraction absorbed from gut lumen ( F a ) is also assumed to be one because F a is usually unknown. Here, we found that such assumptions lead to serious errors in predictions of AUCR. To resolve this, we propose a new framework to predict AUCR. Specifically, F a was re-estimated from experimental permeability values rather than assuming it to be one. Importantly, we used the total quasi-steady-state approximation to derive a new equation, which is valid regardless of the relationship between K m and E T , unlike the MM model. Thus, our framework becomes much more accurate than the original FDA equation, especially for drugs with high affinities, such as midazolam or strong inducers, such as rifampicin, so that the ratio between K m and E T becomes low (i.e., the MM model is invalid). Our work greatly improves the prediction of clinical DDIs, which is critical to preventing drug toxicity and failure.
Assuntos
Citocromo P-450 CYP3A , Sistema Enzimático do Citocromo P-450 , Humanos , Interações Medicamentosas , Preparações Farmacêuticas , Sistema Enzimático do Citocromo P-450/metabolismo , Rifampina/farmacologia , MidazolamRESUMO
Dynamic hydrogel systems from N,O-carboxymethyl chitosan (NOCC) are investigated in the past years, which has facilitated their widespread use in many biomedical engineering applications. However, the influence of the polymer's oxidation levels on the hydrogel biological properties is not fully investigated. In this study, chitosan is converted into NOCC and introduced to react spontaneously with oxidized xanthan gum (OXG) to form several injectable hydrogels with controlled degradability. Different oxidation levels of xanthan gum, as well as NOCC/OXG volume ratios, are trialed. The infrared spectroscopy spectra verify chemical modification on OXG and successful crosslinking. With increasing oxidation levels, more dialdehyde groups are introduced into the OXG, resulting in changes in physical properties including gelation, swelling, and self-healing efficiency. Under different volume ratios, the hydrogel shows a stable structure and rigidity with higher mechanical properties, and a slower degradation rate. The shear-thinning and self-healing properties of the hydrogels are confirmed. In vitro assays with L929 cells show the biocompatibility of all formulations although the use of a high amount of OXG15 and OXG25 limited the cell proliferation capacity. Findings in this study suggested a suitable amount of OXG at different oxidation levels in NOCC hydrogel systems for tissue engineering applications.
Assuntos
Quitosana , Quitosana/química , Hidrogéis/farmacologia , Hidrogéis/química , PolímerosRESUMO
To understand complex micro/nanoscale ECM stem cell interactions, reproducible in vitro models are needed that can strictly recapitulate the relative content and spatial arrangement of native tissue. Additionally, whole ECM proteins are required to most accurately reflect native binding dynamics. To address this need, we use multiphoton excited photochemistry to create 3D whole protein constructs or "modules" to study how the ECM governs stem cell migration. The constructs were created from mixtures of BSA/laminin (LN) and BSA alone, whose comparison afforded studying how the migration dynamics are governed from the combination of morphological and ECM cues. We found that mesenchymal stem cells interacted for significantly longer durations with the BSA/LN constructs than pure BSA, pointing to the importance of binding cues of the LN. Critical to this work was the development of an automated system with feedback based on fluorescence imaging to provide quality control when synthesizing multiple identical constructs.