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BACKGROUND: Pruritus is a frequently reported and unpleasant side effect following intrathecal opioid use with frequency further increased among parturients. We have performed a systematic review to assess the overall efficacy of ondansetron for the prevention of pruritus in patients receiving intrathecal opioid as part of spinal anesthesia for cesarean delivery. METHODS: A literature search of MEDLINE, Embase, Cochrane, and Web of Science databases was conducted from date of inception to September 2022. Studies that included patients undergoing cesarean delivery with spinal anesthesia using intrathecal opioid were included. The primary outcome was the presence of pruritus, and the secondary outcome was time to onset of pruritus. Data from included studies were pooled for analysis using an appropriately determined random-effects model. Outcomes were presented using forest plots and 95% confidence intervals. Additional sensitivity and subgroup analysis were performed. Trial sequential analysis was conducted for the primary outcome. RESULTS: Twenty-three randomized controlled trials with a total of 2586 patients were included: 1219 received ondansetron, 1030 received a placebo, and a further 337 received a different study drug and were excluded from analysis. Opioids used in the included studies were morphine, fentanyl, and sufentanil. Patients who received ondansetron showed a significant reduction in the incidence of pruritus compared to the control group (RR, 0.81; 95% confidence interval [CI], 0.71-0.92; I 2 = 64%). There was no significant difference in pruritus onset between the groups (mean difference [MD], 17.54 minutes; 95% CI, -2.18 to 37.26; I 2 = 83%). The overall Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessment of quality of evidence was low. CONCLUSIONS: This systematic review has demonstrated a significant reduction in the incidence of pruritus following the use of ondansetron. This is in contrast to previously published meta-analyses. Studies included were of varying quality and some at high risk of bias with a high degree of statistical heterogeneity. Furthermore, high-quality and well-powered studies are required to confirm these findings.
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Analgésicos Opioides , Ondansetron , Gravidez , Humanos , Feminino , Náusea e Vômito Pós-Operatórios/induzido quimicamente , Prurido/induzido quimicamente , Prurido/diagnóstico , Prurido/prevenção & controle , Fentanila , Morfina , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
BACKGROUND: Back pain is a huge global problem. For some people, the pain is so severe that they feel the need to present to an emergency department (ED). Our aim was to explore patient and staff perspectives for the development of a digital care pathway (DCP) for people with back pain who have presented to ED, including acceptability, barriers and facilitators. METHODS: We used a descriptive phenomenology approach using semi-structured interviews with patient and staff participants at a tertiary hospital. Interviews were transcribed and data codes were developed using inductive thematic analysis. Themes were discussed between researchers until consensus was achieved. RESULTS: A total of 16 interviews were carried out, half of which involved patient participants. We identified three major themes: (i) expectations and experiences of staff and patients with low back pain in ED; (ii) a digital care pathway can empower patients and support clinicians in providing care; and (iii) acceptability, barriers, facilitators and recommendations of engaging with a DCP to track the trajectory of back pain. Each theme was further categorised into subthemes. CONCLUSION: Introducing a DCP was perceived as acceptable and beneficial by patients and staff. Both groups were aware of the potential participant burden if surveys were too long. Introducing a DCP could be a valuable adjunct to current management care models, providing a standardised source of education with the potential for individualised tracking and monitoring. The design and development of a DCP will need to consider reported facilitators and address perceived barriers for engagement. PATIENT OR PUBLIC CONTRIBUTION: This project sought insights from patients and staff about a digital care pathway. This forms the first step of patient and consumer consultation before implementing a digital care pathway. All consumers were offered the opportunity to review their responses and our interpretation.
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Serviço Hospitalar de Emergência , Entrevistas como Assunto , Dor Lombar , Pesquisa Qualitativa , Humanos , Dor Lombar/terapia , Feminino , Masculino , Adulto , Pessoa de Meia-Idade , Procedimentos Clínicos , Atitude do Pessoal de Saúde , IdosoRESUMO
Colombia has one of the longest running internal armed conflicts, which has significantly impacted the mental health of the population. This article is the first to present a national level mapping of the provision of mental health services to young people living in Colombia, through detailed review of documentation, interviews with key stakeholders and quantitative analysis of existing data on mental health and suicide. It explores the existing public mental health provision in the country, focussing on where mental health resources are concentrated and how these are implemented. We use this mapping to understand how the current mental health system in Colombia fits with international approaches to youth mental health. We show that whilst mental health policy is variously framed (biomedical, biosocial, psychologically or through human rights), Colombian policy clearly focusses on a differential approach. This differential approach shapes service provision to target support at those in need, consequently neglecting whole population level mental health support. This means that not all stakeholders were clearly articulated or included in policy and that key institutional stakeholders, such as the education sector, were not linked to implementation plans or activity. Policy approaches were also over-centralised with little cross-institutional collaboration. Youth were specifically missing from services, as was explicit understanding of the intergenerational effects and impact of conflict. This was exacerbated by unequal distribution of mental health care services concentrated in populous, urban areas away from conflict-affected regions. Suicide is the second most prevalent cause of death with 10% of population who were recorded as dying by violence, dying from completed suicide. Triangulation implies a strong relationship between suicide and poorer access to professional support in conflict-affected areas and suggests that international frameworks and policy approaches to supporting youth mental health have been insufficiently adapted for conflict and post conflict contexts.
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Serviços de Saúde Mental , Suicídio , Adolescente , Humanos , Colômbia/epidemiologia , Saúde Mental , ViolênciaRESUMO
OBJECTIVES: To identify the priority injury and illness types across UK summer Olympic World Class Programme sports to inform development, implementation and evaluation of associated injury risk mitigation and management initiatives. METHODS: Four years (2016-2019) of electronic medical records of 1247 athletes from 22 sports were analysed and reported using methods based on the 2020 International Olympic Committee consensus statement for epidemiological recording and reporting. RESULTS: 3562 injuries and 1218 illness were recorded, accounting for 146 156 and 27 442 time-loss days. Overall, 814 (65%) athletes reported at least one injury, while 517 (41%) reported at least one illness. There were 1.3 injuries per athlete year resulting in a mean burden of 54.1 days per athlete year. The lumbar/pelvis, knee, ankle and shoulder body regions had the highest incidence and burden. Athletes reported 0.5 illnesses per athlete year, resulting in a mean burden of 10.4 days per athlete year, with most composed of respiratory illness and gastroenteritis. Injuries within sport groups were representative of the injury risk profile for those sports (eg, knee, hand and head injuries had the highest incidence in combat sports), but respiratory illnesses were consistently the greatest problem for each sport group. CONCLUSIONS: To optimise availability for training and performance, systematic risk mitigation and management initiatives should target priority injury problems occurring in the lumbar/pelvis, knee, ankle and shoulder, and respiratory illness. Follow-up analysis should include identification of sport-specific priority health problems and associated risk factors.
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Traumatismos em Atletas , Esportes , Humanos , Traumatismos em Atletas/epidemiologia , Traumatismos em Atletas/etiologia , Atletas , Fatores de Risco , Incidência , Reino Unido/epidemiologiaRESUMO
Physical theories that depend on many parameters or are tested against data from many different experiments pose unique challenges to statistical inference. Many models in particle physics, astrophysics and cosmology fall into one or both of these categories. These issues are often sidestepped with statistically unsound ad hoc methods, involving intersection of parameter intervals estimated by multiple experiments, and random or grid sampling of model parameters. Whilst these methods are easy to apply, they exhibit pathologies even in low-dimensional parameter spaces, and quickly become problematic to use and interpret in higher dimensions. In this article we give clear guidance for going beyond these procedures, suggesting where possible simple methods for performing statistically sound inference, and recommendations of readily-available software tools and standards that can assist in doing so. Our aim is to provide any physicists lacking comprehensive statistical training with recommendations for reaching correct scientific conclusions, with only a modest increase in analysis burden. Our examples can be reproduced with the code publicly available at Zenodo.
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Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease affecting children and young people today. However, it is not a single disease entity, but an umbrella term that gathers together a heterogeneous collection of complex, chronic inflammatory conditions with oligoarticular JIA the most common form in both Europe and North America. Due to its relative rarity in daily practice and potential to mimic other conditions, oligoarticular JIA can present a diagnostic and management challenge to healthcare professionals in both primary care and general paediatrics. The aim of this article is to provide a summary of the key aspects of diagnosis, investigation and management of this condition, with the hopes of building clinicians' confidence when facing a possible case of oligoarticular JIA.
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Artrite Juvenil , Adolescente , Artrite Juvenil/diagnóstico , Artrite Juvenil/tratamento farmacológico , Criança , Europa (Continente) , HumanosRESUMO
BACKGROUND: The purpose of this study was to determine the incidence, characteristics, impact, and risk factors associated with persistent incisional pain. The hypothesis was that patient demographics and perioperative interventions are associated with persistent pain. METHODS: This was a secondary analysis of an international prospective cohort study from 2012 to 2014. This study included patients who were 45 yr of age or older who underwent major inpatient noncardiac surgery. Data were collected perioperatively and at 1 yr after surgery to assess for the development of persistent incisional pain (pain present around incision at 1 yr after surgery). RESULTS: Among 14,831 patients, 495 (3.3%; 95% CI, 3.1 to 3.6) reported persistent incisional pain at 1 yr, with an average pain intensity of 3.6 ± 2.5 (0 to 10 numeric rating scale), with 35% and 14% reporting moderate and severe pain intensities, respectively. More than half of patients with persistent pain reported needing analgesic medications, and 85% reported interference with daily activities (denominator = 495 in the above proportions). Risk factors for persistent pain included female sex (P = 0.007), Asian ethnicity (P < 0.001), surgery for fracture (P < 0.001), history of chronic pain (P < 0.001), coronary artery disease (P < 0.001), history of tobacco use (P = 0.048), postoperative patient-controlled analgesia (P < 0.001), postoperative continuous nerve block (P = 0.010), insulin initiation within 24 h of surgery (P < 0.001), and withholding nonsteroidal anti-inflammatory medication or cyclooxygenase-2 inhibitors on the day of surgery (P = 0.029 and P < 0.001, respectively). Older age (P < 0.001), endoscopic surgery (P = 0.005), and South Asian (P < 0.001), Native American/Australian (P = 0.004), and Latin/Hispanic ethnicities (P < 0.001) were associated with a lower risk of persistent pain. CONCLUSIONS: Persistent incisional pain is a common complication of inpatient noncardiac surgery, occurring in approximately 1 in 30 adults. It results in significant morbidity, interferes with daily living, and is associated with persistent analgesic consumption. Certain demographics, ethnicities, and perioperative practices are associated with increased risk of persistent pain.
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Dor Crônica/epidemiologia , Dor Crônica/etiologia , Dor Pós-Operatória/epidemiologia , Dor Pós-Operatória/etiologia , Ferida Cirúrgica/complicações , Ferida Cirúrgica/epidemiologia , Idoso , Dor Crônica/diagnóstico , Estudos de Coortes , Feminino , Seguimentos , Humanos , Internacionalidade , Masculino , Pessoa de Meia-Idade , Dor Pós-Operatória/diagnóstico , Estudos Prospectivos , Ferida Cirúrgica/diagnósticoRESUMO
Malaria is a devastating parasitic disease caused by parasites from the genus Plasmodium. Therapeutic resistance has been reported against all clinically available antimalarials, threatening our ability to control the disease and therefore there is an ongoing need for the development of novel antimalarials. Towards this goal, we identified the 2-(N-phenyl carboxamide) triazolopyrimidine class from a high throughput screen of the Janssen Jumpstarter library against the asexual stages of the P. falciparum parasite. Here we describe the structure activity relationship of the identified class and the optimisation of asexual stage activity while maintaining selectivity against the human HepG2 cell line. The most potent analogues from this study were shown to exhibit equipotent activity against P. falciparum multidrug resistant strains and P. knowlesi asexual parasites. Asexual stage phenotyping studies determined the triazolopyrimidine class arrests parasites at the trophozoite stage, but it is likely these parasites are still metabolically active until the second asexual cycle, and thus have a moderate to slow onset of action. Non-NADPH dependent degradation of the central carboxamide and low aqueous solubility was observed in in vitro ADME profiling. A significant challenge remains to correct these liabilities for further advancement of the 2-(N-phenyl carboxamide) triazolopyrimidine scaffold as a potential moderate to slow acting partner in a curative or prophylactic antimalarial treatment.
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Antimaláricos/farmacologia , Eritrócitos/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Plasmodium knowlesi/efeitos dos fármacos , Purinas/farmacologia , Antimaláricos/síntese química , Antimaláricos/química , Relação Dose-Resposta a Droga , Eritrócitos/parasitologia , Humanos , Estrutura Molecular , Testes de Sensibilidade Parasitária , Purinas/síntese química , Purinas/química , Relação Estrutura-AtividadeRESUMO
AIM: To characterise the current transfusion practice among clinicians in Australasian neonatal units and factors that influence their decision-making. METHODS: Members of the Australia and New Zealand Neonatal Network (ANZNN) and practitioners at their local institutions were invited to participate in a 15-question web-based survey between 1 June and 31 July 2016. The survey was designed to assess (i) haemoglobin-based transfusion thresholds; (ii) presence of local guidelines; (iii) preference for a restrictive or liberal transfusion policy; (iv) perceived benefits and risks of transfusion; and (v) use of clinical adjuncts to assist decision-making. RESULTS: Overall, 130 participants responded to at least one question. Haemoglobin transfusion thresholds for anaemia of prematurity (AOP) varied significantly from <60 to <120 g/L. Of 103 participants, 36 (35%) reported that they do not have access to local transfusion guidelines. The majority utilise multiple clinical and haematological parameters to guide their decision-making, and approximately half (45/84, 54%) believe that tissue hypoxia detected by near-infrared spectroscopy (NIRS) may better inform transfusion thresholds. Of 102 participants, 51 (50%) support a restrictive rather than liberal transfusion policy. The most commonly reported perceived risks of transfusion for AOP were suppression of endogenous erythropoiesis and increased rates of necrotising enterocolitis. CONCLUSIONS: There is a significant variation in transfusion practice in Australasian neonatal units. Quality and safety initiatives may assist with improved consistency of transfusion practice across the ANZNN. However, further research is required to better define optimal transfusion thresholds, quantify potential risks of transfusion and determine clinical utility of newer adjuncts such as NIRS.
Assuntos
Anemia Neonatal/terapia , Transfusão de Sangue/métodos , Recém-Nascido Prematuro , Inquéritos e Questionários , Anemia Neonatal/diagnóstico , Austrália , Tomada de Decisão Clínica , Estudos de Coortes , Transfusão de Eritrócitos/efeitos adversos , Transfusão de Eritrócitos/métodos , Feminino , Seguimentos , Humanos , Incidência , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Masculino , Nova Zelândia , Seleção de Pacientes , Estudos Retrospectivos , Medição de Risco , Resultado do TratamentoRESUMO
Aberrant activation of matrix metalloproteinases (MMPs) is a common feature of pathological cascades observed in diverse disorders, such as cancer, fibrosis, immune dysregulation, and neurodegenerative diseases. MMP-9, in particular, is highly dynamically regulated in several pathological processes. Development of MMP inhibitors has therefore been an attractive strategy for therapeutic intervention. However, a long history of failed clinical trials has demonstrated that broad-spectrum MMP inhibitors have limited clinical utility, which has spurred the development of inhibitors selective for individual MMPs. Attaining selectivity has been technically challenging because of sequence and structural conservation across the various MMPs. Here, through a biochemical and structural screening paradigm, we have identified JNJ0966, a highly selective compound that inhibited activation of MMP-9 zymogen and subsequent generation of catalytically active enzyme. JNJ0966 had no effect on MMP-1, MMP-2, MMP-3, MMP-9, or MMP-14 catalytic activity and did not inhibit activation of the highly related MMP-2 zymogen. The molecular basis for this activity was characterized as an interaction of JNJ0966 with a structural pocket in proximity to the MMP-9 zymogen cleavage site near Arg-106, which is distinct from the catalytic domain. JNJ0966 was efficacious in reducing disease severity in a mouse experimental autoimmune encephalomyelitis model, demonstrating the viability of this therapeutic approach. This discovery reveals an unprecedented pharmacological approach to MMP inhibition, providing an opportunity to improve selectivity of future clinical drug candidates. Targeting zymogen activation in this manner may also allow for pharmaceutical exploration of other enzymes previously viewed as intractable drug targets.
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Precursores Enzimáticos/antagonistas & inibidores , Precursores Enzimáticos/química , Metaloproteinase 9 da Matriz/química , Inibidores de Metaloproteinases de Matriz/química , Regulação Alostérica , Animais , Células COS , Domínio Catalítico , Chlorocebus aethiops , Precursores Enzimáticos/genética , Precursores Enzimáticos/metabolismo , Humanos , Metaloproteinase 9 da Matriz/genética , Metaloproteinase 9 da Matriz/metabolismo , Domínios ProteicosRESUMO
This paper highlights a bifunctional isocyanide that contains a photoreactive aliphatic diazirine for protein target capture and a terminal alkyne for click chemistry-based proteomics. Specifically, this isocyanide was employed in five different multicomponent reactions to produce 10 different fully functionalized small-molecule probes (FFSMPs) containing eight different chemical scaffolds. We anticipate this bifunctional isocyanide can be used to create FFSMP libraries of much greater chemical diversity toward identifying compounds with novel mechanisms of action via integrated phenotypic screening and target identification.
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Antibody-drug conjugates (ADCs) consist of monoclonal antibodies (mAbs) or antibody fragments conjugated to biologically active molecules (usually highly cytotoxic small molecules) through chemical linkers. Although no ADCs containing covalent-binding DNA-interactive payloads have yet been approved (although two containing the DNA-cleaving payload calicheamicin have), of those in clinical trials systemic toxicities are beginning to emerge. This article discusses the observed toxicities in relation to the structures and mechanisms of action of payload type.
Assuntos
Antineoplásicos/química , Benzodiazepinas/química , DNA/química , Imunoconjugados/química , Pirróis/química , Humanos , Relação Estrutura-AtividadeRESUMO
PURPOSE: We explore the optimal cone-beam CT (CBCT) acquisition parameters to improve CBCT image quality to enhance intracranial stereotactic radiosurgery (SRS) localization and also assess the imaging dose levels associated with each imaging protocol. METHODS: Twenty-six CBCT acquisition protocols were generated on an Edge® linear accelerator (Varian Medical Systems, Palo Alto, CA) with different x-ray tube current and potential settings, gantry rotation trajectories, and gantry rotation speeds. To assess image quality, images of the Catphan 504 phantom were analyzed to evaluate the following image quality metrics: uniformity, HU constancy, spatial resolution, low contrast detection, noise level, and contrast-to-noise ratio (CNR). To evaluate the imaging dose for each protocol, the cone-beam dose index (CBDI) was measured. To validate the phantom results, further analysis was performed with an anthropomorphic head phantom as well as image data acquired for a clinical SRS patient. RESULTS: The Catphan data indicates that adjusting acquisition parameters had direct effects on the image noise level, low contrast detection, and CNR, but had minimal effects on uniformity, HU constancy, and spatial resolution. The noise level was reduced from 34.5 ± 0.3 to 18.5 ± 0.2 HU with a four-fold reduction in gantry speed, and to 18.7 ± 0.2 HU with a four-fold increase in tube current. Overall, the noise level was found to be proportional to inverse square root of imaging dose, and imaging dose was proportional to the product of total tube current-time product and the cube of the x-ray potential. Analysis of the anthropomorphic head phantom data and clinical SRS imaging data also indicates that noise is reduced with imaging dose increase. CONCLUSIONS: Our results indicate that optimization of the imaging protocol, and thereby an increase in the imaging dose, is warranted for improved soft-tissue visualization for intracranial SRS.
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Osso e Ossos/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Cabeça/diagnóstico por imagem , Imagens de Fantasmas , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias de Tecidos Moles/cirurgia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Órgãos em Risco/efeitos da radiação , Prognóstico , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Neoplasias de Tecidos Moles/diagnóstico por imagemRESUMO
BACKGROUND: Migraine is considered a neurovascular disorder, but its pathophysiological mechanisms are not yet fully understood. Adenosine has been shown to increase in plasma during migraine attacks and to induce vasodilation in several blood vessels; however, it remains unknown whether adenosine can interact with the trigeminovascular system. Moreover, caffeine, a non-selective adenosine receptor antagonist, is included in many over the counter anti-headache/migraine treatments. METHODS: This study used the rat closed cranial window method to investigate in vivo the effects of the adenosine A2A receptor antagonists with varying selectivity over A1 receptors; JNJ-39928122, JNJ-40529749, JNJ-41942914, JNJ-40064440 or JNJ-41501798 (0.3-10 mg/kg) on the vasodilation of the middle meningeal artery produced by either CGS21680 (an adenosine A2A receptor agonist) or endogenous CGRP (released by periarterial electrical stimulation). RESULTS: Regarding the dural meningeal vasodilation produced neurogenically or pharmacologically, all JNJ antagonists: (i) did not affect neurogenic vasodilation but (ii) blocked the vasodilation produced by CGS21680, with a blocking potency directly related to their additional affinity for the adenosine A1 receptor. CONCLUSIONS: These results suggest that vascular adenosine A2A (and, to a certain extent, also A1) receptors mediate the CGS21680-induced meningeal vasodilation. These receptors do not appear to modulate prejunctionally the sensory release of CGRP. Prevention of meningeal arterial dilation might be predictive for anti-migraine drugs, and since none of these JNJ antagonists modified per se blood pressure, selective A2A receptor antagonism may offer a novel approach to antimigraine therapy which remains to be investigated in clinical trials.
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Antagonistas do Receptor A2 de Adenosina/farmacologia , Adenosina/análogos & derivados , Artérias Meníngeas/efeitos dos fármacos , Transtornos de Enxaqueca/tratamento farmacológico , Fenetilaminas/farmacologia , Vasodilatação/efeitos dos fármacos , Adenosina/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Estimulação Elétrica , Masculino , Transtornos de Enxaqueca/fisiopatologia , Ratos , Ratos Sprague-DawleyRESUMO
The pyrrolobenzodiazepine (PBD) and duocarmycin families are DNA-interactive agents that covalently bond to guanine (G) and adenine (A) bases, respectively, and that have been joined together to create synthetic dimers capable of cross-linking G-G, A-A, and G-A bases. Three G-A alkylating dimers have been reported in publications to date, with defined DNA-binding sites proposed for two of them. In this study we have used molecular dynamics simulations to elucidate preferred DNA-binding sites for the three published molecular types. For the PBD-CPI dimer UTA-6026 (1), our simulations correctly predicted its favoured binding site (i.e., 5'-C(G)AATTA-3') as identified by DNA cleavage studies. However, for the PBD-CI molecule ('Compound 11', 3), we were unable to reconcile the results of our simulations with the reported preferred cross-linking sequence (5'-ATTTTCC(G)-3'). We found that the molecule is too short to span the five base pairs between the A and G bases as claimed, but should target instead a sequence such as 5'-ATTTC(G)-3' with two less base pairs between the reacting G and A residues. Our simulation results for this hybrid dimer are also in accord with the very low interstrand cross-linking and in vitro cytotoxicity activities reported for it. Although a preferred cross-linking sequence was not reported for the third hybrid dimer ('27eS', 2), our simulations predict that it should span two base pairs between covalently reacting G and A bases (e.g., 5'-GTAT(A)-3').
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Benzodiazepinas/farmacologia , Reagentes de Ligações Cruzadas/farmacologia , DNA/química , Indóis/farmacologia , Pirróis/farmacologia , Sequência de Bases , Benzodiazepinas/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Reagentes de Ligações Cruzadas/química , DNA/efeitos dos fármacos , Dimerização , Relação Dose-Resposta a Droga , Duocarmicinas , Humanos , Indóis/química , Ligantes , Simulação de Dinâmica Molecular , Estrutura Molecular , Pirróis/química , Pirrolidinonas/química , Pirrolidinonas/farmacologia , Relação Estrutura-AtividadeRESUMO
The pyrrolo[2,1-c][1,4]benzodiazepines (PBDs) are a family of sequence-selective DNA minor-groove binding agents that form a covalent aminal bond between their C11-position and the C2-NH2 groups of guanine bases. The first example of a PBD monomer, the natural product anthramycin, was discovered in the 1960s, and the best known PBD dimer, SJG-136 (also known as SG2000, NSC 694501 or BN2629), was synthesized in the 1990s and has recently completed Phase II clinical trials in patients with leukaemia and ovarian cancer. More recently, PBD dimer analogues are being attached to tumor-targeting antibodies to create antibody-drug conjugates (ADCs), a number of which are now in clinical trials, with many others in pre-clinical development. This Review maps the development from anthramycin to the first PBD dimers, and then to PBD-containing ADCs, and explores both structure-activity relationships (SARs) and the biology of PBDs, and the strategies for their use as payloads for ADCs.
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Antramicina/farmacologia , Antibióticos Antineoplásicos/farmacologia , Anticorpos/farmacologia , Benzodiazepinas/farmacologia , Leucemia/tratamento farmacológico , Neoplasias Ovarianas/tratamento farmacológico , Pirróis/farmacologia , Antramicina/síntese química , Antramicina/química , Antibióticos Antineoplásicos/síntese química , Antibióticos Antineoplásicos/química , Anticorpos/química , Benzodiazepinas/síntese química , Benzodiazepinas/química , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Leucemia/patologia , Estrutura Molecular , Neoplasias Ovarianas/patologia , Pirróis/síntese química , Pirróis/químicaRESUMO
2.5 MV electronic portal imaging, available on Varian TrueBeam machines, was characterized using various phantoms in this study. Its low-contrast detectability, spatial resolution, and contrast-to-noise ratio (CNR) were compared with those of conventional 6 MV and kV planar imaging. Scatter effect in large patient body was simulated by adding solid water slabs along the beam path. The 2.5 MV imaging mode was also evaluated using clinically acquired images from 24 patients for the sites of brain, head and neck, lung, and abdomen. With respect to 6 MV, the 2.5 MV achieved higher contrast and preserved sharpness on bony structures with only half of the imaging dose. The quality of 2.5 MV imaging was comparable to that of kV imaging when the lateral separation of patient was greater than 38 cm, while the kV image quality degraded rapidly as patient separation increased. Based on the results of patient images, 2.5 MV imaging was better for cranial and extracranial SRS than the 6 MV imaging.
Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Neoplasias Pulmonares/diagnóstico por imagem , Imagens de Fantasmas , Radiocirurgia/métodos , Neoplasias Encefálicas/cirurgia , Neoplasias de Cabeça e Pescoço/cirurgia , Humanos , Neoplasias Pulmonares/cirurgia , Masculino , Aceleradores de Partículas , Doses de Radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodosRESUMO
The pyrrolobenzodiazepines (PBDs) are a family of covalent-binding DNA-interactive minor-groove binding agents with a thermodynamic preference for binding to 5'-Pu-G-Pu-3' sequences (Pu = Purine) but a kinetic preference for 5'-Py-G-Py-3' (Py = Pyrimidine). Using HPLC/MS methodology and a range of designed hairpin-forming oligonucleotides, the kinetics of reaction of a C8-bis-pyrrole pyrrolobenzodiazepine (PBD) conjugate (GWL-78, 2) with sixteen isomeric oligonucleotides has been evaluated, each containing a single PBD binding site in one of two locations. The PBD-binding base-pair triplets were designed to include every possible combination of A and T bases adjacent to the covalently-reacting guanine, with the set of hairpins consisting of isomeric pairs containing the same sequence in the hairpin stem but with either hexaethylene glycol (HEG) or TTT loops. The PBD 2 reacted most rapidly with TGT and TGA sequences, with the possibility that adducts might form in both the 3'- and 5'-directions with some sequences according to modelling studies. A faster reaction rate was observed for all hairpins containing the HEG loop except one (Seq 10) when the PBD binding triplets were located either near the loop or adjacent to the 5'-end. Modelling studies have suggested that this difference in reactivity could be due to the structural flexibility of the HEG loop allowing both A-ring-3' and A-ring-5' adducts to form, while a TTT loop should favour only A-ring-5' adducts due to steric considerations. These findings contrast with the results reported by Nguyen and Wilson for the interaction of non-covalent DNA-binding molecules with DNA hairpins, where the loop structure was found to have little effect on interaction in the main stem of the hairpin.
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Antineoplásicos/metabolismo , Benzodiazepinas/metabolismo , Adutos de DNA/química , Adutos de DNA/genética , Dipeptídeos/metabolismo , Sequências Repetidas Invertidas , Pareamento de Bases , Sequência de Bases , Adutos de DNA/metabolismo , Modelos MolecularesRESUMO
Crispene E, a new clerodane-type diterpene, inhibited STAT3 dimerization in a cell-free fluorescent polarisation assay and was found to have significant toxicity against STAT3-dependent MDA-MB 231 breast cancer cell line and selectively inhibited the expression of STAT3 and STAT3 target genes cyclin D1, Fascin and bcl-2. Molecular docking studies suggest the molecule inhibits STAT3 by interacting with its SH2 domain. The compound has been isolated from Tinospora crispa and characterized using standard spectroscopic techniques.