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BACKGROUND: Sick neonates with haemodynamic instability often require complex medication regimens, which may result in the connection of a catecholamine infusion distally. This increases the dead volume of the infusion system, extending the time to medication delivery. This study evaluated the effects of body weight, and infusion connection point on the delivery rate of two medications infused through a multi-infusion system at infusion rates suitable for extremely and very low birth weight (ELBW and VLBW) neonates. METHODS: An infusion system consisting of six infusions was used to investigate time to delivery, drug concentration at time to delivery and quantity of adrenaline and dopamine administered by intravenous infusions at infusion rates suitable for premature neonates. RESULTS: In an ELBW neonate model, the measured adrenaline and dopamine concentration at 12 T was higher than expected (66.7 (7.5)% (mean (SD)) and 68.0 (4.4)%, respectively, P < 0.001). At the calculated time to delivery, neither drug reached target concentration. In a VLBW neonate model, the measured adrenaline and dopamine concentration at 12 T was higher than expected (92.2 (7.1)% and 97.1 (3.1)%, respectively, P < 0.001). Adrenaline reached target concentration at 27 (11) min and dopamine at 56 (12) min, times significantly shorter than calculated. The measured quantity of adrenaline and dopamine delivered was lower (P < 0.001) than calculated in all tested combinations except adrenaline at proximal connection (97.2 (3.4)%, P = 0.097) in the VLBW neonate model. CONCLUSIONS: Using the most proximal available infusion connection considerably improves drug delivery times and drug doses delivered, which is critical during the administration of short-acting cardiovascular medications.
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Dopamina , Sistemas de Liberação de Medicamentos , Epinefrina , Recém-Nascido Prematuro , Recém-Nascido de muito Baixo Peso , Recém-Nascido , Humanos , Infusões Intravenosas , Dopamina/administração & dosagem , Epinefrina/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Recém-Nascido de Peso Extremamente Baixo ao NascerRESUMO
OBJECTIVES: Lung cancer is the leading cause of cancer death in the UK. Prehabilitation aims to maximise patient fitness and minimise the negative impact of anticancer treatment. What constitutes prehabilitation before non-surgical anticancer treatment is not well established. We present data from a pilot project of Early prehabilitation In lung Cancer. METHODS: All new patients with likely advanced lung cancer were offered prehabilitation at respiratory clinic, if fit for further investigation. Prehabilitation included assessment and appropriate intervention from a consultant in palliative medicine, registered dietitian and rehabilitation physiotherapist. Four objective endpoints were identified, namely admissions to hospital, time spent in the hospital, treatment rates and overall survival. Outcomes were to be compared with 178 prehab eligible historical controls diagnosed from 2019 to 2021. RESULTS: From July 2021 to June 2023, 65 patients underwent prehabilitation and 72% of patients underwent all 3 interventions. 54 patients had a stage 3 or 4 lung cancer. In the prehab group, fewer patients attended Accident and Emergency (31.5 vs 37.4 attendances per 100 patients) and fewer were admitted (51.9 vs 67.9) when compared with historical controls. Those receiving prehab spent a lot less time in the hospital (129.7 vs 543.5 days per 100 patients) with shorter admissions (2.5 vs 8 days). Systemic anticancer treatment rates increased in the short term but were broadly similar overall. Median survival was higher in the prehabilitation group (0.73 vs 0.41 years, p=0.046). CONCLUSIONS: Early prehabilitation appears to reduce time spent in the hospital. It may improve survival. Further work is required to understand its full effect on treatment rates.
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INTRODUCTION: Parenteral drug administration in the neonatal intensive care involves complex pharmacotherapy adjusted for the patient's weight, fluid allowance, and complex multi-infusion systems. OBJECTIVES: We investigated the delivery rate of a model drug through a multi-infusion system consisting of six intravenous infusions. METHODS: Delivery rate of the model drug was determined after infusion initiation and termination. Measurements were collected spectrophotometrically in real time. Time to drug delivery and the amount of drug delivered were measured. KEY FINDINGS: The longest time to drug delivery was observed for a 500 g neonate model with a distal infusion connection point and neutral pump position (337 ± 30 min, P < 0.001). The shortest time was observed for a 1000 g neonate model in the combination of proximal infusion connection point and neutral pump position (18 ± 12 min, P < 0.05). The expected 100% of the drug was delivered only in two combinations: 500 g and 1000 g neonate models, proximal infusion connection point and neutral pump position (100.4 ± 4.7%, P = 0.819 and 100.2 ± 2.7%, P = 0.874, respectively). While the least drug was delivered to a 500 g neonate model in the combination of distal infusion connection point and neutral pump position (27.5 ± 5.8%, P < 0.001). CONCLUSIONS: Delayed drug delivery to premature neonates due to multi-infusion systems may compromise accurate drug administration and lead to dosing errors.
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Sistemas de Liberação de Medicamentos , Bombas de Infusão , Recém-Nascido , Humanos , Infusões Parenterais , Infusões Intravenosas , Preparações Farmacêuticas , Peso CorporalRESUMO
The paraventricular nucleus (PVN) of the hypothalamus plays a vital role in maintaining homeostasis and modulates cardiovascular function via autonomic pre-sympathetic neurones. We have previously shown that coupling between transient receptor potential cation channel subfamily V Member 4 (Trpv4) and small-conductance calcium-activated potassium channels (SK) in the PVN facilitate osmosensing, but since TRP channels are also thermosensitive, in this report we investigated the temperature sensitivity of these neurones. Methods: TRP channel mRNA was quantified from mouse PVN with RT-PCR and thermosensitivity of Trpv4-like PVN neuronal ion channels characterised with cell-attached patch-clamp electrophysiology. Following recovery of temperature-sensitive single-channel kinetic schema, we constructed a predictive stochastic mathematical model of these neurones and validated this with electrophysiological recordings of action current frequency. Results: 7 thermosensitive TRP channel genes were found in PVN punches. Trpv4 was the most abundant of these and was identified at the single channel level on PVN neurones. We investigated the thermosensitivity of these Trpv4-like channels; open probability (Po) markedly decreased when temperature was decreased, mediated by a decrease in mean open dwell times. Our neuronal model predicted that PVN spontaneous action current frequency (ACf) would increase as temperature is decreased and in our electrophysiological experiments, we found that ACf from PVN neurones was significantly higher at lower temperatures. The broad-spectrum channel blocker gadolinium (100 µM), was used to block the warm-activated, Ca2+-permeable Trpv4 channels. In the presence of gadolinium (100 µM), the temperature effect was largely retained. Using econazole (10 µM), a blocker of Trpm2, we found there were significant increases in overall ACf and the temperature effect was inhibited. Conclusion: Trpv4, the abundantly transcribed thermosensitive TRP channel gene in the PVN appears to contribute to intrinsic thermosensitive properties of PVN neurones. At physiological temperatures (37°C), we observed relatively low ACf primarily due to the activity of Trpm2 channels, whereas at room temperature, where most of the previous characterisation of PVN neuronal activity has been performed, ACf is much higher, and appears to be predominately due to reduced Trpv4 activity. This work gives insight into the fundamental mechanisms by which the body decodes temperature signals and maintains homeostasis.
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Both stability and compatibility of parenteral nutrition solutions (PNS) with drug products are major concerns for clinicians and clinical pharmacists, especially when concurrent administration of PNS with intravenous medications (IVM) is unavoidable. Since the same physicochemical principles apply to both adult's and paediatrics' PNS, concerns about stability and compatibility may still apply to both. However, these concerns are relatively more common in paediatrics and neonatal clinical settings, where limited vascular access can be problematic and the coadministration of PNS and drugs is more common. In neonatal and paediatric populations, there have been few experimental studies and comprehensive evaluations looking at medication compatibility with frequently used PNS. This work is part of a larger research project concerned for compatibility of PNS with commonly used intravenous medication in paediatric and neonates. This paper captures and reviews published data on factors influencing stability and compatibility of parenteral nutrition solutions. This information will help clinicians and clinical pharmacists to understand the principals of the stability and compatibility of PNS, furthermore, it will inform better design of future compatibility studies, as it highlights the complexity of PNS and the multiple factors influencing the stability of PNS, and hence its compatibility with IVM. When preparing, prescribing, and administering the PNS, especially when co-administration with IVM is unavoidable, it is important to take into account the physicochemical properties of the PNS components and IVM as well as administration conditions and environmental factors. These factors should also be considered in the design of the compatibility studies of the PNS with the IVM.
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Soluções de Nutrição Parenteral , Recém-Nascido , Humanos , Criança , Soluções de Nutrição Parenteral/química , Preparações Farmacêuticas , Estabilidade de MedicamentosRESUMO
AIM: The EMA defines acceptability as "the overall ability and willingness of the patient to use, and their caregiver to administer, the medicine as intended" [1]. This paper seeks to outline issues of acceptability in relation to injectable therapy, namely intravenous (IV), intramuscular (IM) and subcutaneous (SC) administration routes, and to lay a foundation to identify a minimum set of data that would satisfy Regulatory Authorities when discussing the acceptability of an injectable product. In addition, it will alert drug product developers to other factors that might contribute to good practice, alternative administration strategies and overall adherence to achieve successful treatment. Whilst the term 'parenteral' means "outside the intestine" [2,3] and so potentially covers a range of administration routes including intranasal and percutaneous administration, this review focuses on IV, IM and SC administration by injection. The use of indwelling canulae or catheters to reduce venepuncture and facilitate prolonged treatment is common and may impact acceptability [4]. This may be influenced by information provided by the manufacturer but is not always in their direct control. Other injectable products suitable for routes such as intradermal, intra-articular, intraosseous and intrathecal, share the requirement to be acceptable but are not specifically covered in this paper [2,5].
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Injeções Subcutâneas , Humanos , Criança , Administração Cutânea , Administração Intranasal , Administração Intravenosa , Injeções IntramuscularesRESUMO
Selecting the appropriate formulation and solubility-enabling technology for poorly water soluble drugs is an essential element in the development of formulations for paediatric patients. Different methodologies and structured strategies are available to select a suitable approach and guide formulation scientists for development of adult formulations. However, there is paucity of available literature for selection of technology and overcoming the challenges in paediatric formulation development. The need for flexible dosing, and the limited knowledge of the safety of many formulation excipients in paediatric subjects, impose significant constraints and in some instances require adaptation of the approaches taken to formulating these drugs for the adult population. Selection of the best drug delivery system for paediatrics requires an efficient, systematic approach that considers a drug's physical and chemical properties and the targeted patient population's requirements. This review is a step towards development of a strategy for the design of solubility enhancing paediatric formulations of highly insoluble drugs. The aim of this review is to provide an overview of different approaches and strategies to consider in order to assist development of paediatric formulation for poorly water-soluble drugs with the provision of examples of some marketed products. In addition, it provides recommendations to overcome the range of challenges posed by these strategies and adaptations of the adult approach/product presentation required to enable paediatric drug development and administration.
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Excipientes , Água , Administração Oral , Adulto , Criança , Sistemas de Liberação de Medicamentos , Excipientes/química , Humanos , Preparações Farmacêuticas/química , Solubilidade , Água/químicaRESUMO
In humans, skin is a primary thermoregulatory organ, with vasodilation leading to rapid body cooling, whereas in Rodentia the tail performs an analogous function. Many thermodetection mechanisms are likely to be involved including transient receptor potential vanilloid-type 4 (TRPV4), an ion channel with thermosensitive properties. Previous studies have shown that TRPV4 is a vasodilator by local action in blood vessels, so here, we investigated whether constitutive TRPV4 activity affects Mus muscularis tail vascular tone and thermoregulation. We measured tail blood flow by pressure plethysmography in lightly sedated M. muscularis (CD1 strain) at a range of ambient temperatures, with and without intraperitoneal administration of the blood-brain barrier crossing TRPV4 antagonist GSK2193874. We also measured heart rate (HR) and blood pressure. As expected for a thermoregulatory organ, we found that tail blood flow increased with temperature. However, unexpectedly, we found that GSK2193874 increased tail blood flow at all temperatures, and we observed changes in HR variability. Since local TRPV4 activation causes vasodilation that would increase tail blood flow, these data suggest that increases in tail blood flow resulting from the TRPV4 antagonist may arise from a site other than the blood vessels themselves, perhaps in central cardiovascular control centres.
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Quinolinas , Vasodilatação , Animais , Regulação da Temperatura Corporal , Camundongos , Piperidinas , Canais de Cátion TRPV/fisiologia , Vasodilatação/fisiologiaRESUMO
Development of automated analysis tools for "single ion channel" recording is hampered by the lack of available training data. For machine learning based tools, very large training sets are necessary with sample-by-sample point labelled data (e.g., 1 sample point every 100microsecond). In an experimental context, such data are labelled with human supervision, and whilst this is feasible for simple experimental analysis, it is infeasible to generate the enormous datasets that would be necessary for a big data approach using hand crafting. In this work we aimed to develop methods to generate simulated ion channel data that is free from assumptions and prior knowledge of noise and underlying hidden Markov models. We successfully leverage generative adversarial networks (GANs) to build an end-to-end pipeline for generating an unlimited amount of labelled training data from a small, annotated ion channel "seed" record, and this needs no prior knowledge of theoretical dynamical ion channel properties. Our method utilises 2D CNNs to maintain the synchronised temporal relationship between the raw and idealised record. We demonstrate the applicability of the method with 5 different data sources and show authenticity with t-SNE and UMAP projection comparisons between real and synthetic data. The model would be easily extendable to other time series data requiring parallel labelling, such as labelled ECG signals or raw nanopore sequencing data.
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Processamento de Imagem Assistida por Computador , Redes Neurais de Computação , Algoritmos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Armazenamento e Recuperação da Informação , Aprendizado de MáquinaRESUMO
The impact of the COVID-19 pandemic on pharmacy education worldwide has been immense, affecting students, educators and regulatory agencies. Pharmacy programmes have had to rapidly adapt in their delivery of education, maintaining standards while also ensuring the safety of all stakeholders. In this commentary, we describe the challenges, compromises and solutions adopted by our institution throughout the pandemic, the lessons learnt, adaptive measures taken, and strategies to develop and future-proof our curricula.
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COVID-19 , Educação em Farmácia , Farmácia , Estudantes de Farmácia , COVID-19/epidemiologia , Currículo , Humanos , PandemiasRESUMO
Limited toxicity data on electronic cigarette (ECIG) impede evidence-based policy recommendations. We compared two popular mixed fruit flavored ECIG-liquids with and without nicotine aerosolized at 40 W (E-smoke) with respect to particle number concentrations, chemical composition, and response on physiologically relevant human bronchial and alveolar lung mucosa models cultured at air-liquid interface. E-smoke was characterized by significantly increased particle number concentrations with increased wattage (25, 40, and 55 W) and nicotine presence. The chemical composition of E-smoke differed across the two tested flavors in terms of cytotoxic compounds including p-benzoquinone, nicotyrine, and flavoring agents (for example vanillin, ethyl vanillin). Significant differences in the expression of markers for pro-inflammation, oxidative stress, tissue injury/repair, alarm anti-protease, anti-microbial defense, epithelial barrier function, and epigenetic modification were observed between the flavors, nicotine content, and/ or lung models (bronchial or alveolar). Our findings indicate that ECIG toxicity is influenced by combination of multiple factors including flavor, nicotine content, vaping regime, and the region of respiratory tree (bronchial or alveolar). Toxic chemicals and flavoring agents detected in high concentrations in the E-smoke of each flavor warrant independent evaluation for their specific role in imparting toxicity. Therefore, multi-disciplinary approaches are warranted for comprehensive safety profiling of ECIG.
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Brônquios/citologia , Marcadores Genéticos/efeitos dos fármacos , Nicotina/efeitos adversos , Alvéolos Pulmonares/citologia , Vaping/efeitos adversos , Brônquios/química , Brônquios/efeitos dos fármacos , Técnicas de Cultura de Células , Linhagem Celular , Sistemas Eletrônicos de Liberação de Nicotina , Aromatizantes/efeitos adversos , Aromatizantes/química , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Modelos Biológicos , Tamanho da Partícula , Alvéolos Pulmonares/química , Alvéolos Pulmonares/efeitos dos fármacosRESUMO
The synovium secretes synovial fluid, but is also richly innervated with nociceptors and acts as a gateway between avascular joint tissues and the circulatory system. Resident fibroblast-like synoviocytes' (FLS) calcium-activated potassium channels (K Ca) change in activity in arthritis models and this correlates with FLS activation. OBJECTIVE: To investigate this activation in an in vitro model of inflammatory arthritis; 72 h treatment with cytokines TNFα and IL1ß. METHODS: FLS cells were isolated from rat synovial membranes. We analyzed global changes in FLS mRNA by RNA-sequencing, then focused on FLS ion channel genes and the corresponding FLS electrophysiological phenotype and finally modeling data with ingenuity pathway analysis (IPA) and MATLAB. RESULTS: IPA showed significant activation of inflammatory, osteoarthritic and calcium signaling canonical pathways by cytokines, and we identified â¼200 channel gene transcripts. The large K Ca (BK) channel consists of the pore forming Kcnma1 together with ß-subunits. Following cytokine treatment, a significant increase in Kcnma1 RNA abundance was detected by qPCR and changes in several ion channels were detected by RNA-sequencing, including a loss of BK channel ß-subunit expression Kcnmb1/2 and an increase in Kcnmb3. In electrophysiological experiments, there was a decrease in over-all current density at 20 mV without change in chord conductance at this potential. CONCLUSION: TNFα and IL1ß treatment of FLS in vitro recapitulated several common features of inflammatory arthritis at the transcriptomic level, including increase in Kcnma1 and Kcnmb3 gene expression.
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OBJECTIVE: Intravenous (IV) sildenafil, a phosphodiesterase type 5 inhibitor, is increasingly being used for the treatment of pulmonary hypertension (PH) in the paediatric population. Sildenafil (Revatio®) is approved for the treatment of pH in adults where it is administered as a bolus injection. However, in paediatrics it is used off-label and administered by continuous IV infusion. In the critically unwell child, limited IV access necessitates the administration of multiple IV infusions through a single IV lumen. The absence of compatibility data between sildenafil and other IV medications commonly used in this context necessitates the use of a dedicated IV line for sildenafil. The overall aim of this study was to establish the physical and chemical compatibility of sildenafil with commonly administered infusions in the paediatric and neonatal intensive care setting. DESIGN: This study evaluated the chemical and physical compatibility of binary and multiple combinations (n = 42) of sildenafil with adrenaline, noradrenaline, milrinone, vasopressin and heparin. These were tested using three diluents (NaCl 0.9%w/v, Glucose 5%w/v, and Glucose 10%w/v) and two environmental conditions (room temperature and 37 °C) frequently encountered in paediatric or neonatal intensive care units. Prior to drug combination analysis, HPLC methods were developed and optimised to allow for the quantification of drugs in accordance with current pharmaceutical guidance. Binary and multiple drug mixtures of sildenafil were examined for physical and chemical compatibility to establish compatibility. MEASUREMENTS AND MAIN RESULTS: Of the drug combinations not containing heparin, all were deemed compatible with the exception of the five drug mix of Sildenafil 800 µg/mL, Milrinone 200 µg/mL, Vasopressin 0.4Units/mL, Noradrenaline 60 µg/mL, Adrenaline 60 µg/mL at 37 °C, in 10%w/v glucose. All binary or multi drug combinations containing heparin were deemed incompatible. CONCLUSIONS: This research provides support and information to clinicians looking to co-administer sildenafil with other IV medicines thus removing the requirement to subject their patients to multiple intravenous cannula insertion points where IV access is restricted. ARTICLE TWEET: New evidence to support administration of sildenafil infusions in #PedsICU and #nicu- collaboration between @RCSIPharBioMol@FionaSOBrien1 and @OLCHCrumlin @RCSI_Irl @MoninneHowlett #CHI.
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Citrato de Sildenafila/administração & dosagem , Administração Intravenosa/métodos , Combinação de Medicamentos , Quimioterapia Combinada/métodos , Humanos , Hipertensão Pulmonar/tratamento farmacológico , Infusões Intravenosas/métodos , Terapia Intensiva Neonatal , Pediatria/métodos , Preparações Farmacêuticas/administração & dosagemRESUMO
Single-molecule research techniques such as patch-clamp electrophysiology deliver unique biological insight by capturing the movement of individual proteins in real time, unobscured by whole-cell ensemble averaging. The critical first step in analysis is event detection, so called "idealisation", where noisy raw data are turned into discrete records of protein movement. To date there have been practical limitations in patch-clamp data idealisation; high quality idealisation is typically laborious and becomes infeasible and subjective with complex biological data containing many distinct native single-ion channel proteins gating simultaneously. Here, we show a deep learning model based on convolutional neural networks and long short-term memory architecture can automatically idealise complex single molecule activity more accurately and faster than traditional methods. There are no parameters to set; baseline, channel amplitude or numbers of channels for example. We believe this approach could revolutionise the unsupervised automatic detection of single-molecule transition events in the future.
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Fenômenos Eletrofisiológicos , Ativação do Canal Iônico , Canais Iônicos/metabolismo , Redes Neurais de Computação , Técnicas de Patch-Clamp , Imagem Individual de Molécula , Inteligência Artificial , Humanos , Modelos Biológicos , Curva ROC , Imagem Individual de Molécula/métodos , Aprendizado de Máquina Supervisionado , Fluxo de TrabalhoRESUMO
The development of age-appropriate formulations should focus on dosage forms that can deliver variable yet accurate doses that are safe and acceptable to the child, are matched to his/her development and ability, and avoid medication errors. However, in the past decade, the medication needs of neonates have largely been neglected. The aim of this review is to expand on what differentiates the needs of preterm and term neonates from those of the older paediatric subsets, in terms of environment of care, ability to measure and administer the dose (from the perspective of the patient and carer, the routes of administration, the device and the product), neonatal biopharmaceutics and regulatory challenges. This review offers insight into those challenges posed by the formulation of medicinal products for neonatal patients in order to support the development of clinically relevant products.
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Preparações Farmacêuticas/administração & dosagem , Medicina de Precisão , Fatores Etários , Química Farmacêutica , Vias de Administração de Medicamentos , Composição de Medicamentos , Estabilidade de Medicamentos , Humanos , Recém-Nascido , Preparações Farmacêuticas/química , Medicina de Precisão/métodosRESUMO
KEY POINTS: There are two subtypes of trimeric intracellular cation (TRIC) channels but their distinct single-channel properties and physiological regulation have not been characterized. We examined the differences in function between native skeletal muscle sarcoplasmic reticulum (SR) K+ -channels from wild-type (WT) mice (where TRIC-A is the principal subtype) and from Tric-a knockout (KO) mice that only express TRIC-B. We find that lone SR K+ -channels from Tric-a KO mice have a lower open probability and gate more frequently in subconducting states than channels from WT mice but, unlike channels from WT mice, multiple channels gate with high open probability with a more than six-fold increase in activity when four channels are present in the bilayer. No evidence was found for a direct gating interaction between ryanodine receptor and SR K+ -channels in Tric-a KO SR, suggesting that TRIC-B-TRIC-B interactions are highly specific and may be important for meeting counterion requirements during excitation-contraction coupling in tissues where TRIC-A is sparse or absent. ABSTRACT: The trimeric intracellular cation channels, TRIC-A and TRIC-B, represent two subtypes of sarcoplasmic reticulum (SR) K+ -channel but their individual functional roles are unknown. We therefore compared the biophysical properties of SR K+ -channels derived from the skeletal muscle of wild-type (WT) or Tric-a knockout (KO) mice. Because TRIC-A is the major TRIC-subtype in skeletal muscle, WT SR will predominantly contain TRIC-A channels, whereas Tric-a KO SR will only contain TRIC-B channels. When lone SR K+ -channels were incorporated into bilayers, the open probability (Po) of channels from Tric-a KO mice was markedly lower than that of channels from WT mice; gating was characterized by shorter opening bursts and more frequent brief subconductance openings. However, unlike channels from WT mice, the Po of SR K+ -channels from Tric-a KO mice increased as increasing channel numbers were present in the bilayer, driving the channels into long sojourns in the fully open state. When co-incorporated into bilayers, ryanodine receptor channels did not directly affect the gating of SR K+ -channels, nor did the presence or absence of SR K+ -channels influence ryanodine receptor activity. We suggest that because of high expression levels in striated muscle, TRIC-A produces most of the counterion flux required during excitation-contraction coupling. TRIC-B, in contrast, is sparsely expressed in most cells and, although lone TRIC-B channels exhibit low Po, the high Po levels reached by multiple TRIC-B channels may provide a compensatory mechanism to rapidly restore K+ gradients and charge differences across the SR of tissues containing few TRIC-A channels.
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Retículo Endoplasmático/metabolismo , Canais Iônicos/metabolismo , Músculo Esquelético/fisiologia , Retículo Sarcoplasmático/metabolismo , Animais , Feminino , Canais Iônicos/genética , Troca Iônica , Masculino , Camundongos , Camundongos Knockout , Canais de Potássio de Abertura Dependente da Tensão da Membrana/fisiologiaRESUMO
The paraventricular nucleus of the hypothalamus (PVN) is critical for the regulation of homeostatic function. Although also important for endocrine regulation, it has been referred to as the "autonomic master controller." The emerging consensus is that the PVN is a multifunctional nucleus, with autonomic roles including (but not limited to) coordination of cardiovascular, thermoregulatory, metabolic, circadian and stress responses. However, the cellular mechanisms underlying these multifunctional roles remain poorly understood. Neurones from the PVN project to and can alter the function of sympathetic control regions in the medulla and spinal cord. Dysfunction of sympathetic pre-autonomic neurones (typically hyperactivity) is linked to several diseases including hypertension and heart failure and targeting this region with specific pharmacological or biological agents is a promising area of medical research. However, to facilitate future medical exploitation of the PVN, more detailed models of its neuronal control are required; populated by a greater compliment of constituent ion channels. Whilst the cytoarchitecture, projections and neurotransmitters present in the PVN are reasonably well documented, there have been fewer studies on the expression and interplay of ion channels. In this review we bring together an up to date analysis of PVN ion channel studies and discuss how these channels may interact to control, in particular, the activity of the sympathetic system.
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Acceptability of medicinal products in children and older populations is pivotal in ensuring adherence and therapeutic outcomes. This review systematically identifies studies reporting on formulation aspects of oral medications that affect their acceptability in these patient groups. Particular emphasis is placed on the evaluation of the methodologies employed in the studies. Sixty-eight studies were included for analysis, with 51 (75%) in children and 17 (25%) in older populations. The studies evaluated a range of oral formulations; however, the methodologies used differ considerably in participants' characteristics, study settings, tools, acceptability definitions and criteria. It is evident that there is a lack of standardisation in study design as well as the assessment methods used in assessing acceptability of medicines in children and older populations.
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Adesão à Medicação/estatística & dados numéricos , Projetos de Pesquisa/normas , Administração Oral , Idoso , Química Farmacêutica/métodos , Criança , HumanosRESUMO
Nicotinic acid adenine dinucleotide phosphate (NAADP) and cyclic ADP-ribose (cADPR) are Ca2+-mobilizing messengers important for modulating cardiac excitation-contraction coupling and pathophysiology. CD38, which belongs to the ADP-ribosyl cyclase family, catalyzes synthesis of both NAADP and cADPR in vitro However, it remains unclear whether this is the main enzyme for their production under physiological conditions. Here we show that membrane fractions from WT but not CD38-/- mouse hearts supported NAADP and cADPR synthesis. Membrane permeabilization of cardiac myocytes with saponin and/or Triton X-100 increased NAADP synthesis, indicating that intracellular CD38 contributes to NAADP production. The permeabilization also permitted immunostaining of CD38, with a striated pattern in WT myocytes, whereas CD38-/- myocytes and nonpermeabilized WT myocytes showed little or no staining, without striation. A component of ß-adrenoreceptor signaling in the heart involves NAADP and lysosomes. Accordingly, in the presence of isoproterenol, Ca2+ transients and contraction amplitudes were smaller in CD38-/- myocytes than in the WT. In addition, suppressing lysosomal function with bafilomycin A1 reduced the isoproterenol-induced increase in Ca2+ transients in cardiac myocytes from WT but not CD38-/- mice. Whole hearts isolated from CD38-/- mice and exposed to isoproterenol showed reduced arrhythmias. SAN4825, an ADP-ribosyl cyclase inhibitor that reduces cADPR and NAADP synthesis in mouse membrane fractions, was shown to bind to CD38 in docking simulations and reduced the isoproterenol-induced arrhythmias in WT hearts. These observations support generation of NAADP and cADPR by intracellular CD38, which contributes to effects of ß-adrenoreceptor stimulation to increase both Ca2+ transients and the tendency to disturb heart rhythm.
Assuntos
ADP-Ribosil Ciclase 1/metabolismo , Sinalização do Cálcio , ADP-Ribose Cíclica/metabolismo , Glicoproteínas de Membrana/metabolismo , Miócitos Cardíacos/metabolismo , NADP/análogos & derivados , Retículo Sarcoplasmático/metabolismo , ADP-Ribosil Ciclase 1/antagonistas & inibidores , Agonistas Adrenérgicos beta/farmacologia , Animais , Antiarrítmicos/química , Antiarrítmicos/metabolismo , Antiarrítmicos/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Células Cultivadas , Detergentes/farmacologia , Inibidores Enzimáticos/farmacologia , Coração/efeitos dos fármacos , Técnicas In Vitro , Masculino , Glicoproteínas de Membrana/antagonistas & inibidores , Camundongos Endogâmicos C57BL , Camundongos Knockout , Simulação de Acoplamento Molecular , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , NADP/metabolismo , Transporte Proteico/efeitos dos fármacos , Coelhos , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/enzimologia , Análise de Célula ÚnicaRESUMO
KEY POINTS: The role of trimeric intracellular cation (TRIC) channels is not known, although evidence suggests they may regulate ryanodine receptors (RyR) via multiple mechanisms. We therefore investigated whether Tric-a gene knockout (KO) alters the single-channel function of skeletal RyR (RyR1). We find that RyR1 from Tric-a KO mice are more sensitive to inhibition by divalent cations, although they respond normally to cytosolic Ca2+ , ATP, caffeine and luminal Ca2+ . In the presence of Mg2+ , ATP cannot effectively activate RyR1 from Tric-a KO mice. Additionally, RyR1 from Tric-a KO mice are not activated by protein kinase A phosphorylation, demonstrating a defect in the ability of ß-adrenergic stimulation to regulate sarcoplasmic reticulum (SR) Ca2+ -release. The defective RyR1 gating that we describe probably contributes significantly to the impaired SR Ca2+ -release observed in skeletal muscle from Tric-a KO mice, further highlighting the importance of TRIC-A for normal physiological regulation of SR Ca2+ -release in skeletal muscle. ABSTRACT: The type A trimeric intracellular cation channel (TRIC-A) is a major component of the nuclear and sarcoplasmic reticulum (SR) membranes of cardiac and skeletal muscle, and is localized closely with ryanodine receptor (RyR) channels in the SR terminal cisternae. The skeletal muscle of Tric-a knockout (KO) mice is characterized by Ca2+ overloaded and swollen SR and by changes in the properties of SR Ca2+ release. We therefore investigated whether RyR1 gating behaviour is modified in the SR from Tric-a KO mice by incorporating native RyR1 into planar phospholipid bilayers under voltage-clamp conditions. We find that RyR1 channels from Tric-a KO mice respond normally to cytosolic Ca2+ , ATP, adenine, caffeine and to luminal Ca2+ . However, the channels are more sensitive to the inactivating effects of divalent cations, thus, in the presence of Mg2+ , ATP is inadequate as an activator. Additionally, channels are not characteristically activated by protein kinase A even though the phosphorylation levels of Ser2844 are similar to controls. The results of the present study suggest that TRIC-A functions as an excitatory modulator of RyR1 channels within the SR terminal cisternae. Importantly, this regulatory action of TRIC-A appears to be independent of (although additive to) any indirect consequences to RyR1 activity that arise as a result of K+ fluxes across the SR via TRIC-A.