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1.
Mol Cell ; 81(19): 3992-4007.e10, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34562373

RESUMO

ParB-like CTPases mediate the segregation of bacterial chromosomes and low-copy number plasmids. They act as DNA-sliding clamps that are loaded at parS motifs in the centromere of target DNA molecules and spread laterally to form large nucleoprotein complexes serving as docking points for the DNA segregation machinery. Here, we solve crystal structures of ParB in the pre- and post-hydrolysis state and illuminate the catalytic mechanism of nucleotide hydrolysis. Moreover, we identify conformational changes that underlie the CTP- and parS-dependent closure of ParB clamps. The study of CTPase-deficient ParB variants reveals that CTP hydrolysis serves to limit the sliding time of ParB clamps and thus drives the establishment of a well-defined ParB diffusion gradient across the centromere whose dynamics are critical for DNA segregation. These findings clarify the role of the ParB CTPase cycle in partition complex assembly and function and thus advance our understanding of this prototypic CTP-dependent molecular switch.


Assuntos
Proteínas de Bactérias/metabolismo , Segregação de Cromossomos , Cromossomos Bacterianos , Citidina Trifosfato/metabolismo , DNA Bacteriano/metabolismo , Myxococcus xanthus/enzimologia , Proteínas de Bactérias/genética , Sítios de Ligação , Domínio Catalítico , Cristalografia por Raios X , DNA Bacteriano/genética , Regulação Bacteriana da Expressão Gênica , Hidrólise , Mutação , Myxococcus xanthus/genética , Conformação Proteica , Relação Estrutura-Atividade , Especificidade por Substrato , Fatores de Tempo
2.
PLoS Biol ; 21(1): e3001946, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36719873

RESUMO

Large carnivores have long fascinated human societies and have profound influences on ecosystems. However, their conservation represents one of the greatest challenges of our time, particularly where attacks on humans occur. Where human recreational and/or livelihood activities overlap with large carnivore ranges, conflicts can become particularly serious. Two different scenarios are responsible for such overlap: In some regions of the world, increasing human populations lead to extended encroachment into large carnivore ranges, which are subject to increasing contraction, fragmentation, and degradation. In other regions, human and large carnivore populations are expanding, thus exacerbating conflicts, especially in those areas where these species were extirpated and are now returning. We thus face the problem of learning how to live with species that can pose serious threats to humans. We collected a total of 5,440 large carnivore (Felidae, Canidae, and Ursidae; 12 species) attacks worldwide between 1950 and 2019. The number of reported attacks increased over time, especially in lower-income countries. Most attacks (68%) resulted in human injuries, whereas 32% were fatal. Although attack scenarios varied greatly within and among species, as well as in different areas of the world, factors triggering large carnivore attacks on humans largely depend on the socioeconomic context, with people being at risk mainly during recreational activities in high-income countries and during livelihood activities in low-income countries. The specific combination of local socioeconomic and ecological factors is thus a risky mix triggering large carnivore attacks on humans, whose circumstances and frequencies cannot only be ascribed to the animal species. This also implies that effective measures to reduce large carnivore attacks must also consider the diverse local ecological and social contexts.


Assuntos
Canidae , Carnívoros , Ursidae , Animais , Humanos , Ecossistema , Conservação dos Recursos Naturais/métodos
3.
Nucleic Acids Res ; 51(12): 6495-6506, 2023 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-36919612

RESUMO

5-methylcytosine (mC) and its TET-oxidized derivatives exist in CpG dyads of mammalian DNA and regulate cell fate, but how their individual combinations in the two strands of a CpG act as distinct regulatory signals is poorly understood. Readers that selectively recognize such novel 'CpG duplex marks' could be versatile tools for studying their biological functions, but their design represents an unprecedented selectivity challenge. By mutational studies, NMR relaxation, and MD simulations, we here show that the selectivity of the first designer reader for an oxidized CpG duplex mark hinges on precisely tempered conformational plasticity of the scaffold adopted during directed evolution. Our observations reveal the critical aspect of defined motional features in this novel reader for affinity and specificity in the DNA/protein interaction, providing unexpected prospects for further design progress in this novel area of DNA recognition.


Assuntos
5-Metilcitosina , DNA , Epigênese Genética , Animais , Ilhas de CpG/genética , DNA/química , Metilação de DNA , Epigenômica , Mamíferos/metabolismo , Conformação Molecular
4.
NMR Biomed ; : e5144, 2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38556777

RESUMO

OBJECTIVES: To evaluate the role of combined intravoxel incoherent motion and diffusion kurtosis imaging (IVIM-DKI) and their machine-learning-based texture analysis for the detection and assessment of severity in prostate cancer (PCa). MATERIALS AND METHODS: Eighty-eight patients underwent MRI on a 3 T scanner after giving informed consent. IVIM-DKI data were acquired using 13 b values (0-2000 s/mm2) and analyzed using the IVIM-DKI model with the total variation (TV) method. PCa patients were categorized into two groups: clinically insignificant prostate cancer (CISPCa) (Gleason grade ≤ 6) and clinically significant prostate cancer (CSPCa) (Gleason grade ≥ 7). One-way analysis-of-variance, t test, and receiver operating characteristic analysis was performed to measure the discriminative ability to detect PCa using IVIM-DKI parameters. A chi-square test was used to select important texture features of apparent diffusion coefficient (ADC) and IVIM-DKI parameters. These selected texture features were used in an artificial neural network for PCa detection. RESULTS: ADC and diffusion coefficient (D) were significantly lower (p < 0.001), and kurtosis (k) was significantly higher (p < 0.001), in PCa as compared with benign prostatic hyperplasia (BPH) and normal peripheral zone (PZ). ADC, D, and k showed high areas under the curves (AUCs) of 0.92, 0.89, and 0.88, respectively, in PCa detection. ADC and D were significantly lower (p < 0.05) as compared with CISPCa versus CSPCa. D for detecting CSPCa was high, with an AUC of 0.63. A negative correlation of ADC and D with GS (ADC, ρ = -0.33; D, ρ = -0.35, p < 0.05) and a positive correlation of k with GS (ρ = 0.22, p < 0.05) were observed. Combined IVIM-DKI texture showed high AUC of 0.83 for classification of PCa, BPH, and normal PZ. CONCLUSION: D, f, and k computed using the IVIM-DKI model with the TV method were able to differentiate PCa from BPH and normal PZ. Texture features of combined IVIM-DKI parameters showed high accuracy and AUC in PCa detection.

5.
Microb Pathog ; 186: 106494, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38065294

RESUMO

Bacterial vaginosis (BV) is a recurring, chronic infection that is difficult to treat due to the limited bioavailability of antimicrobials within vaginal epithelial cells. Vaginal administration, because of lower dosing and systemic exposure offers a viable option for treating vaginal infections. In this study, Metronidazole-loaded chitosan nanoparticles were synthesised employing borax (BX) or tannic acid (TA) as an antimicrobial crosslinking agent for treating BV. The prepared NPs were characterized for various physical, physicochemical, pharmaceutical, thermal and antibacterial properties. Morphological investigation revealed that nanoparticles prepared from 0.5 % w/v chitosan, 1.2 % w/v BX, and 0.4 % w/v metronidazole (MTZ) were non-spherical, with particle sizes of 377.4 ± 37.3 nm and a zeta potential of 34 ± 2.1 mV. The optimised formulation has MIC values of 24 ± 0.5 and 59 ± 0.5 µg/mL, against Escherichia coli (E.coli) and Candida albicans (C.albicans) respectively. The results of DSC and XRD demonstrated no change in the physical state of the drug in the finished formulation. Under simulated vaginal fluid, the optimised formulation demonstrates a cumulative drug release of about 90 % within 6h. The prepared borax crosslinked NPs exhibit anti-fungal activities by inhibiting ergosterol synthesis. The in-vivo antibacterial data indicated a comparable reduction in bacterial count compared to the marketed formulation in female Swiss albino mice treated with optimised nanoparticles. According to histopathological findings, the prepared nanoparticle was safe for vaginal use. Based on the experimental findings, it was concluded that MBCSNPs, due to their good physiochemical and antimicrobial properties, could serve as a potential topical alternative for treating BV and reducing fungal infection.


Assuntos
Quitosana , Nanopartículas , Vaginose Bacteriana , Feminino , Humanos , Animais , Camundongos , Metronidazol/farmacologia , Vaginose Bacteriana/tratamento farmacológico , Quitosana/química , Portadores de Fármacos/química , Antibacterianos/química , Nanopartículas/química , Tamanho da Partícula
6.
Langmuir ; 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38320269

RESUMO

Molybdenum disulfide (MoS2) is a two-dimensional (2D) material that offers molecular transport and sieving properties and might be a potential candidate for membrane technologies for energy and environmental applications. To facilitate the separation application, understanding the structural and dynamic properties of water near the substrate-aqueous solution is essential. Employing the molecular dynamics simulation, we investigate the density, local water network at the solid-liquid interface, and water dynamics in aqueous electrolyte solutions with various chloride salts confined in MoS2 nanochannels with different pore sizes and electrolyte concentrations. Our simulation results confirm that the layering of interfacial water at the hydrophilic MoS2 surface and the water density variation depends on the nature of the ions. The simulation results imply a strong attraction of cations to the surface-liquid interfaces, whereas anions are expelled from the surface due to electrostatic interaction. An examination of the dynamical property of water reveals that the confinement effect is more pronounced on water mobility when the pore width is less than 3 nm, and the salt concentration is below 1 M, whereas the electrolyte concentration greater than 1 M, ions predominantly drive the water mobility as compared to confinement one. These simulation results enhance experimental observations and provide molecular insights into the local ordering mechanism that can be crucial in controlling water dynamics in nanofiltration applications.

7.
Exp Cell Res ; 424(1): 113488, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36736226

RESUMO

Glioma is difficult-to-treat because of its infiltrative nature and the presence of the blood-brain barrier. Temozolomide is the only FDA-approved drug for its management. Therefore, finding a novel chemotherapeutic agent for glioma is of utmost importance. Magnolol, a neolignan, has been known for its apoptotic role in glioma. In this work, we have explored a novel anti-glioma mechanism of Magnolol associated with its role in autophagy modulation. We found increased expression levels of Beclin-1, Atg5-Atg12, and LC3-II and lower p62 expression in Magnolol-treated glioma cells. PI3K/AKT/mTOR pathway proteins were also downregulated in Magnolol-treated glioma cells. Next, we treated the glioma cells with Insulin, a stimulator of PI3K/AKT/mTOR signaling, to confirm that Magnolol induced autophagy by inhibiting this pathway. Insulin reversed the effect on Magnolol-mediated autophagy induction. We also established the same in in vivo glioma model where Magnolol showed an anti-glioma effect by inducing autophagy. To confirm the cytotoxic effect of Magnolol-induced autophagy, we used Chloroquine, a late-stage autophagy inhibitor. Chloroquine efficiently reversed the anti-glioma effects of Magnolol both in vitro and in vivo. Our study revealed the cytotoxic effect of Magnolol-induced autophagy in glioma, which was not previously reported. Additionally, Magnolol showed no toxicity in non-cancerous cell lines as well as rat organs. Thus, we concluded that Magnolol is an excellent candidate for developing new therapeutic strategies for glioma management.


Assuntos
Antineoplásicos , Glioma , Insulinas , Lignanas , Ratos , Animais , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Antineoplásicos/farmacologia , Lignanas/farmacologia , Lignanas/uso terapêutico , Glioma/tratamento farmacológico , Glioma/metabolismo , Autofagia , Cloroquina/farmacologia , Cloroquina/uso terapêutico , Insulinas/farmacologia , Insulinas/uso terapêutico , Linhagem Celular Tumoral , Apoptose
8.
Chem Biodivers ; 21(6): e202400147, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38687689

RESUMO

The current study describes the efficacy of B. acutangula fruit extract in wound healing via incorporation within topical gels. B. acutangula fruit extract was produced by solvent extraction method. The bioactive extract was incorporated within Carbopol 940-based topical gels, which were applied topically over the excision and incision wounds. The change in healing process was observed till 20 days. The percentages of closure of excision wound area were 92.89 % and 93.43 %, when treated with topical herbal gels containing B. acutangula fruit extract of 5 % and 10 %, respectively. The tensile strengths of incision area in rats treated with topical herbal gels containing 5 % and 10 % methanol extract of B. acutangula fruits were found to be 25±5.12 g and 30±4.10 g, respectively. The wound healing activity of topical herbal gels containing B. acutangula fruit extract in rats was found to be significant when compared with that of the reference standard and untreated groups. In addition, in silico studies suggested about good skin permeability and binding to the proteins responsible for delaying wound healing. It can be concluded that this topical herbal gels containing B. acutangula fruit extract could be used clinically for the treatment of wounds.


Assuntos
Frutas , Géis , Extratos Vegetais , Cicatrização , Animais , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/administração & dosagem , Cicatrização/efeitos dos fármacos , Frutas/química , Géis/química , Ratos , Administração Tópica , Ratos Wistar , Masculino , Pele/efeitos dos fármacos , Pele/metabolismo , Simulação por Computador
9.
J Assoc Physicians India ; 72(4): 59-67, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38881085

RESUMO

Systemic vasculitis is an immune-mediated group of disorders broadly classified based on the involved vessel type. It has myriad clinical presentations, adding to the challenge of timely diagnosis and management. Thus, imaging has taken center stage in the diagnosis of these disorders as there is a lack of definitive clinical diagnostic markers. Various available imaging modalities can be used for diagnosis and follow-up on these patients. The coronavirus disease 2019 (COVID-19) has added a new dimension to the already existing problem of vasculitis. The virus has shown great affinity for the vascular endothelium, leading to multisystem organ vasculitis. There has been a spike in vasculitis cases in the COVID-19 pandemic era, thus necessitating more research and studies in this field for a better understanding of the disease. In this review, we wish to summarize the various imaging spectrums of classical systemic vasculitis along with the new addition of COVID-19-related vasculitis to the already long list.


Assuntos
COVID-19 , Vasculite Sistêmica , Humanos , COVID-19/complicações , Vasculite Sistêmica/diagnóstico por imagem , Vasculite Sistêmica/diagnóstico , SARS-CoV-2
10.
AAPS PharmSciTech ; 25(4): 85, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38605158

RESUMO

Cervical cancer (CC) is the fourth leading cancer type in females globally. Being an ailment of the birth canal, primitive treatment strategies, including surgery, radiation, or laser therapy, bring along the risk of infertility, neonate mortality, premature parturition, etc. Systemic chemotherapy led to systemic toxicity. Therefore, delivering a smaller cargo of therapeutics to the local site is more beneficial in terms of efficacy as well as safety. Due to the regeneration of cervicovaginal mucus, conventional dosage forms come with the limitations of leaking, the requirement of repeated administration, and compromised vaginal retention. Therefore, these days novel strategies are being investigated with the ability to combat the limitations of conventional formulations. Novel carriers can be engineered to manipulate bioadhesive properties and sustained release patterns can be obtained thus leading to the maintenance of actives at therapeutic level locally for a longer period. Other than the purpose of CC treatment, these delivery systems also have been designed as postoperative care where a certain dose of antitumor agent will be maintained in the cervix postsurgical removal of the tumor. Herein, the most explored localized delivery systems for the treatment of CC, namely, nanofibers, nanoparticles, in situ gel, liposome, and hydrogel, have been discussed in detail. These carriers have exceptional properties that have been further modified with the aid of a wide range of polymers in order to serve the required purpose of therapeutic effect, safety, and stability. Further, the safety of these delivery systems toward vital organs has also been discussed.


Assuntos
Antineoplásicos , Nanopartículas , Neoplasias do Colo do Útero , Feminino , Recém-Nascido , Humanos , Neoplasias do Colo do Útero/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Lipossomos , Hidrogéis
11.
AAPS PharmSciTech ; 25(5): 106, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38724834

RESUMO

The primary factor underlying the virulence of Candida albicans is its capacity to form biofilms, which in turn leads to recurrent complications. Over-the-counter antifungal treatments have proven ineffective in eliminating fungal biofilms and the inflammatory cytokines produced during fungal infections. Chitosan nanoparticles offer broad and versatile therapeutic potential as both antifungal agents and carriers for antifungal drugs to combat biofilm-associated Candida infections. In our study, we endeavoured to develop chitosan nanoparticles utilising chitosan and the antifungal crosslinker phytic acid targeting C. albicans. Phytic acid, known for its potent antifungal and anti-inflammatory properties, efficiently crosslinks with chitosan. The nanoparticles were synthesised using the ionic gelation technique and subjected to analyses including Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential analysis. The synthesised nanoparticles exhibited dimensions with a diameter (Dh) of 103 ± 3.9 nm, polydispersity index (PDI) of 0.33, and zeta potential (ZP) of 37 ± 2.5 mV. These nanoparticles demonstrated an antifungal effect with a minimum inhibitory concentration (MIC) of 140 ± 2.2 µg/mL, maintaining cell viability at approximately 90% of the MIC value and reducing cytokine levels. Additionally, the nanoparticles reduced ergosterol content and exhibited a 62% ± 1.2 reduction in biofilm susceptibility, as supported by colony-forming unit (CFU) and XTT assays-furthermore, treatment with nanoparticles reduced exopolysaccharide production and decreased secretion of aspartyl protease by C. albicans. Our findings suggest that the synthesised nanoparticles effectively combat Candida albicans infections. In vivo studies conducted on a mouse model of vaginal candidiasis confirmed the efficacy of the nanoparticles in combating fungal infections in vivo.


Assuntos
Antifúngicos , Biofilmes , Candida albicans , Quitosana , Testes de Sensibilidade Microbiana , Nanopartículas , Ácido Fítico , Quitosana/química , Biofilmes/efeitos dos fármacos , Nanopartículas/química , Antifúngicos/farmacologia , Antifúngicos/administração & dosagem , Animais , Candida albicans/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana/métodos , Ácido Fítico/farmacologia , Ácido Fítico/administração & dosagem , Ácido Fítico/química , Feminino , Candidíase/tratamento farmacológico , Tamanho da Partícula , Portadores de Fármacos/química , Reagentes de Ligações Cruzadas/química , Citocinas/metabolismo
12.
AAPS PharmSciTech ; 25(2): 31, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38326518

RESUMO

Drug delivery to the buccal mucosa is one of the most convenient ways to treat common mouth problems. Here, we propose a spray-dried re-dispersible mucoadhesive controlled release gargle formulation to improve the efficacy of chlorhexidine. The present investigation portrays an approach to get stable and free-flowing spray-dried porous aggregates of chlorhexidine-loaded sodium alginate nanoparticles. The ionic gelation technique aided with the chlorhexidine's positive surface charge-based crosslinking, followed by spray drying of the nanoparticle's dispersion in the presence of lactose- and leucine-yielded nano-aggregates with good flow properties and with a size range of about 120-350 nm. Provided with the high entrapment efficiency (87%), the particles showed sustained drug release behaviors over a duration of 10 h, where 87% of the released drug got permeated within 12 h. The antimicrobial activity of the prepared formulation was tested on S. aureus, provided with a higher zone of growth inhibition than the marketed formulation. Aided with an appropriate mucoadhesive strength, this product exhibited extended retention of nanoparticles in the throat region, as shown by in vivo imaging results. In conclusion, the technology, provided with high drug retention and extended effect, could be a potential candidate for treating several types of throat infections.


Assuntos
Clorexidina , Faringe , Staphylococcus aureus , Sistemas de Liberação de Medicamentos/métodos , Preparações de Ação Retardada , Antissépticos Bucais , Tamanho da Partícula
13.
Prostate ; 83(2): 169-178, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36259290

RESUMO

BACKGROUND: Genomic defects in DNA-damage repair (DDR) mechanisms have been proposed to affect the radiosensitivity of prostate cancers. In this study, we intended to evaluate the prevalence of genetic alterations in a cohort of metastatic castration-resistant prostate cancer (mCRPC) patients undergoing radioligand therapy (RLT) with prostate-specific membrane antigen (PSMA)-inhibitors as well as the impact of such mutations on treatment outcomes. METHODS: Data of consecutive mCRPC patients from 2017 to 2021 who were treated with PSMA-RLT and underwent next-generation sequencing (NGS) were collected and analyzed for response and survival outcomes. RESULTS: In 95 patients of mCRPC treated with PSMA-RLT, 15 patients (median age: 66 years, range: 50-73 years; [177 Lu]Lu-PSMA-617, n = 12; [225 Ac]Ac-PSMA-617, n = 3) underwent NGS. The median progression-free survival (PFS) of this cohort was 3 months (95% confidence interval: 1.6-4.4 months). On NGS, 21 genetic alterations were reported in 10/15 (67%) patients, of which 13 were DDR-associated alterations involving the genes: ATM (n = 3), BRCA2 (n = 3), TP53 (n = 2), PTEN (n = 2), FANCD2 (n = 1), FANCM (n = 1), and NBN (n = 1). Overall, 5/15 (33%) patients harbored six pathogenic variants (BRCA2, n = 2; ATM, n = 1; TP53, n = 1; PTEN, n = 2). No significant difference was noted for the biochemical response, radiological response, PFS, and overall survival between the patients with and without genetic alterations. CONCLUSIONS: Patients of mCRPC undergoing PSMA-RLT were frequently seen to harbor DDR-associated aberrations, albeit with no significant impact on treatment outcomes. Large prospective trials comparing PSMA-RLT-related outcomes in DDR-deficient and -proficient patients are required to bring out the differences, if any, in a more observable manner.


Assuntos
Neoplasias de Próstata Resistentes à Castração , Idoso , Humanos , Masculino , Dipeptídeos/uso terapêutico , DNA Helicases , Genômica , Compostos Heterocíclicos com 1 Anel/uso terapêutico , Lutécio/uso terapêutico , Estudos Prospectivos , Antígeno Prostático Específico , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/radioterapia , Estudos Retrospectivos , Resultado do Tratamento , Pessoa de Meia-Idade
14.
Br J Haematol ; 201(2): 249-255, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36529704

RESUMO

Arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) form the backbone of the treatment of acute promyelocytic leukaemia (APL), with the addition of chemotherapy for high-risk patients. We describe our experience of treating patients with APL of all risk classes with ATO and ATRA without chemotherapeutic agents. Patients received induction with ATO and ATRA followed by three cycles of consolidation with ATO and ATRA (each 1 month apart) after achieving morphological remission. Patients with intermediate- and high-risk disease received a further 2 years of maintenance with ATRA, 6-mercaptopurine and methotrexate. A total of 206 patients were included in the study. The majority of the patients were intermediate risk (51.9%), followed by high risk (43.2%). Differentiation syndrome was seen in 41 patients (19.9%). Overall, 25 patients (12.1%) died within 7 days of initiating therapy. Seven patients relapsed during follow-up. The mean (SD) estimated 5-year event-free survival (EFS) and overall survival (OS) in the entire cohort was 79% [5.8%] and 80% [5.8%] respectively. After excluding patients who died within 7 days of therapy initiation, the mean (SD) estimated 5-year EFS and OS was 90% [5.8%] and 93% [3.9%] respectively. Our study shows that treatment of all risk classes of APL with ATO and ATRA without chemotherapy is associated with excellent long-term outcomes in the real-world setting.


Assuntos
Trióxido de Arsênio , Leucemia Promielocítica Aguda , Tretinoína , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Trióxido de Arsênio/uso terapêutico , Arsenicais/efeitos adversos , Óxidos/efeitos adversos , Estudos Retrospectivos , Resultado do Tratamento , Tretinoína/uso terapêutico
15.
Nephrol Dial Transplant ; 38(11): 2456-2463, 2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37113073

RESUMO

Systemic mastocytosis (SM) is a disorder of excessive mast cell accumulation in tissues due to a somatic gain-of-function mutation, commonly in the KIT gene, which prevents apoptosis of mast cells. Whereas bone marrow, skin, lymph nodes, spleen and gastrointestinal tract are commonly involved, kidneys are rarely involved directly by SM. However, there are increasing reports of indirect kidney involvement in patients with SM. Novel anti-neoplastic agents to treat advanced forms of SM include non-specific tyrosine kinase inhibitors, which are reported to be associated with kidney dysfunction in some patients. SM is also associated with immune-mediated glomerulonephritis (GN) such as mesangioproliferative GN, membranous nephropathy and diffuse proliferative GN. Kidney injury, in the form of monoclonal deposition disease and primary light chain amyloidosis, is reported in SM associated with plasma cell dyscrasia. In this narrative review we discuss the various ways kidneys (and the urinary tract) are involved in patients with SM.


Assuntos
Glomerulonefrite , Mastocitose Sistêmica , Sistema Urinário , Humanos , Mastocitose Sistêmica/complicações , Mastocitose Sistêmica/diagnóstico , Mastocitose Sistêmica/genética , Mastócitos/patologia , Medula Óssea/patologia , Rim/patologia , Glomerulonefrite/patologia , Mutação
16.
Eur Radiol ; 33(7): 4981-4993, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36826499

RESUMO

OBJECTIVE: To investigate the diagnostic performance of a multiparametric magnetic resonance imaging (MRI) protocol comprising quantitative MRI (diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI), and dynamic contrast-enhanced (DCE) perfusion MRI) and conventional MRI in the characterization of gallbladder wall thickening (GWT). METHODS: This prospective study comprised consecutive adults with GWT who underwent multiparametric MRI between July 2020 and April 2022. Two radiologists evaluated the MRI independently. The final diagnosis was based on surgical histopathology. The association of MRI parameters with malignant GWT was evaluated. The area under the curve (AUC) for the quantitative MRI parameters and diagnostic performance of conventional, and multiparametric MRI were compared. The interobserver agreement between two radiologists was calculated. RESULTS: Thirty-five patients (mean age, 56 years, 23 females) with GWT (25 benign and ten malignant) were evaluated. The quantitative MRI parameters significantly associated with malignant GWT were apparent diffusion coefficient on DWI (p = 0.007) and mean diffusivity (MD) on DTI (p = 0.013), perfusion fraction (f) on IVIM (p = 0.033), time to peak enhancement (TTP, p = 0.008), and wash in rate (p = 0.049) on DCE-MRI. TTP had the highest AUC of 0.790, followed by MD (0.782) and f (0.742) (p = 0.213) for predicting malignant GWT. Multiparametric MRI had significantly higher sensitivity (90% vs. 80%, p = 0.045) than conventional MRI for diagnosing malignant GWT. The two radiologists' reading had substantial to near-perfect agreement (kappa = 0.639-1) and moderate to strong correlation (interclass correlation coefficient = 0.5-0.88). CONCLUSION: Multiparametric protocol incorporating advanced sequences improved the diagnostic performance of MRI for differentiating benign and malignant GWT. KEY POINTS: • Multiparametric MRI had 90% sensitivity and 88% specificity for diagnosing malignant GWT, compared to 80% sensitivity and 88% specificity for conventional CE-MRI. • Among the quantitative MRI parameters, TTP (perfusion-MRI) had the highest AUC of 0.790, followed by MD (0.782) and IVIM-f (0.742). • For most quantitative MRI parameters, there was moderate to strong agreement (ICC = 0.5-0.88).


Assuntos
Imagem de Tensor de Difusão , Vesícula Biliar , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Meios de Contraste/farmacologia , Imageamento por Ressonância Magnética/métodos , Imagem de Difusão por Ressonância Magnética/métodos , Perfusão , Movimento (Física)
17.
AJR Am J Roentgenol ; 220(6): 850-851, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36350117

RESUMO

Perineural invasion (PNI) indicates a worse prognosis for patients with gallbladder cancer (GBC). This preliminary retrospective study included 19 patients with GBC who under-went contrast-enhanced CT in the 4 weeks before undergoing surgical resection. GBC showed PNI on pathologic assessment in eight of 19 patients. On CT, wall thickening morphology had sensitivity of 75.0% and specificity of 81.8% for PNI; soft-tissue stranding around the celiac plexus had sensitivity of 62.5% and specificity of 100.0% for PNI.


Assuntos
Neoplasias da Vesícula Biliar , Humanos , Estudos Retrospectivos , Neoplasias da Vesícula Biliar/diagnóstico por imagem , Neoplasias da Vesícula Biliar/cirurgia , Neoplasias da Vesícula Biliar/patologia , Prognóstico , Tomografia Computadorizada por Raios X , Invasividade Neoplásica/patologia
18.
Phys Chem Chem Phys ; 25(20): 14147-14157, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37162325

RESUMO

Telomerase is an RNA-dependent DNA polymerase that plays a role in the maintenance of the 3' end of the eukaryotic chromosome, known as a telomere, by catalyzing the DNA polymerization reaction in cancer and embryonic stem cells. The detailed molecular details of the DNA polymerization by telomerase, especially the general base for deprotonating the terminal 3'-hydroxyl, which triggers the chemical reaction, remain elusive. We conducted a computational investigation using hybrid quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations to probe the detailed mechanism of the reaction. Our simulations started with the telomerase:RNA:DNA:dNTP ternary complex, and by using enhanced sampling QM/MM MD simulations, we probed the general base involved directly in the polymerization. We report the participation of an aspartate (Asp344) coordinated to Mg and an active site water molecule, jointly acting as a base during nucleic acid addition. The Asp344 residue remains transiently protonated during the course of the reaction, and later it deprotonates by transferring its proton to the water at the end of the reaction.


Assuntos
Simulação de Dinâmica Molecular , Telomerase , Polimerização , Telomerase/química , Telomerase/genética , Telomerase/metabolismo , DNA/química , Água
19.
Exp Cell Res ; 417(1): 113195, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35561786

RESUMO

The Transforming growth factor-ß1 (TGF- ß1) in the tumor microenvironment (TME) is the major cytokine that acts as a mediator of tumor-stroma crosstalk, which in fact has a dual role in either promoting or suppressing tumor development. The cancer-associated fibroblasts (CAFs) are the major cell types in the TME, and the interaction with most of the epithelial cancers is the prime reason for cancer survival. However, the molecular mechanisms, associated with the TGF- ß1 induced tumor promotion through tumor-CAF crosstalk are not well understood. In the Reverse Warburg effect, CAFs feed the adjacent cancer cells by lactate produced during the aerobic glycolysis. We hypothesized that the monocarboxylate transporter, MCT4 which is implicated in lactate efflux from the CAFs, must be overexpressed in the CAFs. Contextually, to explore the role of TGF- ß1 in the hypoxia-induced autophagy in CAFs, we treated CoCl2 and external TGF- ß1 to the human dermal fibroblasts and L929 murine fibroblasts. We demonstrated that hypoxia accelerated the TGF- ß1 signaling and subsequent transformation of normal fibroblasts to CAFs. Moreover, we elucidated that synergistic induction of autophagy by hypoxia and TGF- ß1 upregulate the aerobic glycolysis and MCT4 expression in CAFs. Furthermore, we showed a positive correlation between glucose consumption and MCT4 expression in the CAFs. Autophagy was also found to be involved in the EMT in hypoxic CAFs. Collectively, these findings reveal the unappreciated role of autophagy in TME, which enhances the CAF transformation and that promotes tumor migration and metastasis via the reverse Warburg effect.


Assuntos
Autofagia , Fibroblastos Associados a Câncer , Transportadores de Ácidos Monocarboxílicos/metabolismo , Proteínas Musculares/metabolismo , Neoplasias , Fator de Crescimento Transformador beta1/metabolismo , Animais , Fibroblastos Associados a Câncer/patologia , Regulação Neoplásica da Expressão Gênica , Glicólise , Humanos , Hipóxia/metabolismo , Ácido Láctico/metabolismo , Camundongos , Neoplasias/patologia , Microambiente Tumoral , Regulação para Cima
20.
J Ultrasound Med ; 42(12): 2873-2881, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37676901

RESUMO

OBJECTIVES: Contrast-enhanced ultrasound (CEUS) allows excellent delineation of perfusion in septa and nodules without exposure to ionizing radiation or nephrotoxic contrast media. The aim of our study was to evaluate the role of CEUS for the assessment of cystic renal masses and compare its diagnostic performance with that of CECT. METHODS: Exactly 40 patients diagnosed to have cystic renal masses on CECT scan were prospectively evaluated with CEUS and were assigned a Bosniak class. Based on results of final histopathology and clinical follow-up, internal validity of both CEUS and CECT was evaluated, including agreement between these two modalities. RESULTS: Out of the 40 patients (mean size 3.1 ± 2.5 cm), 23 patients had benign lesions and 17 patients had malignant lesions. For CEUS, the sensitivity and negative predictive value was 100%, the specificity and positive predictive value was 73.9%. For CECT, the sensitivity and negative predictive value were 88.2 and 83.3%, respectively, whereas the specificity and positive predictive value was 87 and 90.9%, respectively. Both imaging modalities had similar accuracy with fair to good agreement with the final diagnosis (Κ = 0.71 and 0.75 for CEUS and CECT, respectively). Concordance between CEUS and CECT was seen in 29 patients (72.5%) with fair agreement between the two modalities (K = 0.66). CONCLUSION: CEUS has comparable accuracy with CECT and could be used as screening modality to rule out the presence of complex cystic renal masses without exposure of nephrotoxic contrast media and ionizing radiation.


Assuntos
Meios de Contraste , Neoplasias Renais , Humanos , Tomografia Computadorizada por Raios X/métodos , Rim/diagnóstico por imagem , Neoplasias Renais/diagnóstico por imagem , Valor Preditivo dos Testes , Ultrassonografia/métodos
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