RESUMEN
OBJECTIVE: Dasatinib and quercetin (D & Q) have demonstrated promise in improving aged-related pathophysiological dysfunctions in humans and mice. Herein we aimed to ascertain whether the heat stress (HS)-induced cognitive deficits in aged or even young adult male mice can be reduced by D & Q therapy. METHODS: Before the onset of HS, animals were pre-treated with D & Q or placebo for 3 consecutive days every 2 weeks over a 10-week period. Cognitive function, intestinal barrier permeability, and blood-brain barrier permeability were assessed. RESULTS: Compared to the non-HS young adult male mice, the HS young adult male mice or the aged male mice had significantly lesser extents of the exacerbated stress reactions, intestinal barrier disruption, endotoxemia, systemic inflammation and oxidative stress, blood-brain barrier disruption, hippocampal inflammation and oxidative stress, and cognitive deficits evaluated at 7 days post-HS. All the cognitive deficits and other syndromes that occurred in young adult HS mice or in aged HS mice were significantly attenuated by D & Q therapy (P < 0.01). Compared to the young adult HS mice, the aged HS mice had significantly (P < 0.01) higher severity of cognitive deficits and other related syndromes. CONCLUSIONS: First, our data show that aged male mice are more vulnerable to HS-induced cognitive deficits than those of the young adult male mice. Second, we demonstrate that a combination of D and Q therapy attenuates cognitive deficits in heat stressed aged or young adult male mice via broad normalization of the brain-gut-endotoxin axis function.
Asunto(s)
Barrera Hematoencefálica , Dasatinib , Estrés Oxidativo , Quercetina , Animales , Masculino , Dasatinib/farmacología , Dasatinib/uso terapéutico , Quercetina/farmacología , Quercetina/uso terapéutico , Ratones , Barrera Hematoencefálica/efectos de los fármacos , Barrera Hematoencefálica/metabolismo , Estrés Oxidativo/efectos de los fármacos , Envejecimiento/efectos de los fármacos , Disfunción Cognitiva/tratamiento farmacológico , Disfunción Cognitiva/etiología , Respuesta al Choque Térmico/efectos de los fármacos , Permeabilidad/efectos de los fármacos , Quimioterapia Combinada , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Cognición/efectos de los fármacosRESUMEN
AIMS: Food allergy is a major public health concern. Failures of food allergen avoidance and the consequences for those with food hypersensitivity (allergies, intolerances and coeliac disease) have a forensic context. The aim of this study was to collate and analyse the use of action in the United Kingdom (UK) courts as redress following adverse food allergy reactions or failures of allergen management. METHODS: Details of prosecutions during the study period (1 January 2014 to 31 January 2020) were recorded from regular key word Internet searches. National and local news reports were primary sources, along with commentary from enforcement and regulatory professionals. Information was also collected from coroners' inquests by attending hearings and direct contact with coroners and participants in the hearings. Freedom of Information requests were made to local authority enforcement departments. In several cases, the authors had direct involvement in investigations. RESULTS: From 2014 to 2020, there was an increase in reports. Seventy prosecutions were recorded as well as two associated appeals and two applications for Hygiene Emergency Prohibition Notice. This resulted in 68 convictions; seven individuals received custodial sentences, three of which were suspended although one individual had a tagged curfew imposed. Fines ranged from £50 to £93,000. Details of the law applied and the evidence gathering processes are reported. CONCLUSION: Legal action, including landmark prosecutions for Gross Negligence Manslaughter and Preventing Future Deaths reports from coroners, with salience of criminal penalties, has led to changes in labelling law and improved allergen management practices better to protect the interests of patients with food hypersensitivities. A central system of collation of such data, and on 'near misses', will enable more focused root cause analysis to further improve allergen management and reduce patient risk.
Asunto(s)
Hipersensibilidad a los Alimentos , Humanos , Procesos de Grupo , Higiene , Internet , AlérgenosRESUMEN
BACKGROUND: 7,8-Dihydroxyflavone (DHF) mimicks the physiological action of brain-derived neurotrophic factor (BDNF). Since local BDNF delivery to the injured spinal cord enhanced diaphragmatic respiratory function, we aimed to ascertain whether DHF might have similar beneficial effects after Brown-Sequard Syndrome in a rat model of spinal cord lateral hemisection (HX) at the 9th thoracic (T9) vertebral level. METHODS: Three sets of adult female rats were included: sham+vehicle group, T9HX+vehicle group and T9HX+DHF group. On the day of surgery, HX+DHF group received DHF (5 mg/kg) while HX+vehicle group received vehicle. Neurobehavioral function, morphology of motor neurons innervating the tibialis anterior muscle and the transmission in descending motor pathways were evaluated. RESULTS: Adult female rats received T9 HX had paralysis and loss of proprioception on the same side as the injury and loss of pain and temperature on the opposite side. We found that, in this model of Brown-Sequard syndrome, reduced cord dendritic arbor complexity, reduced cord motoneuron numbers, enlarged cord lesion volumes, reduced motor evoked potentials, and cord astrogliosis and microgliosis were noted after T9HX. All of the above-mentioned disorders showed recovery by Day 28 after surgery. Therapy with DHF significantly accelerated the electrophysiological, histological and functional recovery in these T9HX animals. CONCLUSIONS: Our data provide a biological basis for DHF as a neurotherapeutic agent to improve recovery after a Brown-Sequard syndrome. Such an effect may be mediated by synaptic plasticity and glia-mediated inflammation in the spared lumbar motoneuron pools to a T9HX.
Asunto(s)
Síndrome de Brown-Séquard , Traumatismos de la Médula Espinal , Animales , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Síndrome de Brown-Séquard/tratamiento farmacológico , Femenino , Flavonas , Ratas , Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/complicaciones , Traumatismos de la Médula Espinal/tratamiento farmacológico , Traumatismos de la Médula Espinal/patologíaRESUMEN
The analytical techniques applied to verify honey authenticity are multifaceted and often result in complex data rich certificates of analysis that are open to interpretation and may be opaque to stakeholders without specialist knowledge. In these cases, the drawing of an independent overarching opinion is challenging. Two questions arise: (Q1) Is it acceptable to report interpretation, particularly if it is adverse, without exhibiting the supporting data? (Q2) How may a valid overarching opinion on authenticity be derived from a large, partially conflicting, dataset? To Q1, it is demonstrated that full disclosure of the data used in interpretation is mandatory. To Q2 it is proposed, with worked examples, to adopt 'evaluative reporting'; a formalised likelihood ratio thought process used in forensic science for evaluation of findings and their strength assessment. In the absence of consensus on techniques for honey authenticity adoption of reporting conventions will allow objective assessments of reports, with equity to all and provide a better basis to identify and address fraud.
RESUMEN
The composition of honey, a complex natural product, challenges analytical methods attempting to determine its authenticity particularly in the face of sophisticated adulteration. Of the advanced analytical techniques available, only isotope ratio mass spectrometry (IRMS) is generally accepted for its reproducibility and ability to detect certain added sugars, with nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) being subject to stakeholder differences of opinion. Herein, recent reviews of honey adulteration and the techniques to detect it are summarised in the light of which analytical reports are examined that underpinned a media article in late 2020 alleging foreign sugars in UK retailers' own brand honeys. The requirement for multiple analytical techniques leads to complex reports from which it is difficult to draw an overarching and unequivocal authenticity opinion. Thus arose two questions. (1) Is it acceptable to report an adverse interpretation without exhibiting all the supporting data? (2) How may a valid overarching authenticity opinion be derived from a large partially conflicting dataset?
Asunto(s)
Clavos Ortopédicos/efectos adversos , Hemorragia/prevención & control , Procedimientos Ortopédicos/instrumentación , Biopsia/efectos adversos , Biopsia/instrumentación , Hemorragia/etiología , Humanos , Procedimientos Ortopédicos/efectos adversos , Procedimientos Ortopédicos/métodos , Piel/irrigación sanguínea , Cicatrización de HeridasRESUMEN
OBJECTIVE: To describe the immediate impact of the COVID-19 pandemic on cervical screening, colposcopy and treatment volumes in Ontario, Canada. DESIGN: Population-based retrospective observational study. SETTING: Ontario, Canada. POPULATION: People with a cervix age of 21-69 years who completed at least one cervical screening cytology test, colposcopy or treatment procedure for cervical dysplasia between January 2019 and August 2020. METHODS: Administrative databases were used to compare cervical screening cytology, colposcopy and treatment procedure volumes before (historical comparator) and during the first 6 months of the COVID-19 pandemic (March-August 2020). MAIN OUTCOME MEASURES: Changes in cervical screening cytology, colposcopy and treatment volumes; individuals with high-grade cytology awaiting colposcopy. RESULTS: During the first 6 months of the COVID-19 pandemic, the monthly average number of cervical screening cytology tests, colposcopies and treatments decreased by 63.8% (range: -92.3 to -41.0%), 39.7% (range: -75.1 to -14.3%) and 31.1% (range: -43.5 to -23.6%), respectively, when compared with the corresponding months in 2019. Between March and August 2020, on average 292 (-51.0%) fewer high-grade cytological abnormalities were detected through screening each month. As of August 2020, 1159 (29.2%) individuals with high-grade screening cytology were awaiting follow-up colposcopy. CONCLUSIONS: The COVID-19 pandemic has had a substantial impact on key cervical screening and follow-up services in Ontario. As the pandemic continues, ongoing monitoring of service utilisation to inform system response and recovery is required. Future efforts to understand the impact of COVID-19-related disruptions on cervical cancer outcomes will be needed. TWEETABLE ABSTRACT: COVID-19 has had a substantial impact on cervical screening and follow-up services in Ontario, Canada.
Asunto(s)
COVID-19/prevención & control , Colposcopía/estadística & datos numéricos , Neoplasias del Cuello Uterino/diagnóstico , Neoplasias del Cuello Uterino/terapia , Frotis Vaginal/estadística & datos numéricos , Adulto , Anciano , Bases de Datos Factuales , Atención a la Salud/estadística & datos numéricos , Detección Precoz del Cáncer/estadística & datos numéricos , Femenino , Humanos , Persona de Mediana Edad , Ontario , SARS-CoV-2 , Adulto JovenRESUMEN
We aimed to elucidate the role of cortical and hippocampal dendritic spines on neurological deficits associated with hippocampal microgliosis, hippocampal neurogenesis, and neuroinflammation in mice with cortical compact impact (CCI) injury. In the present study, we found that CCI reduced spatial memory mean latency (10 s. vs 50 s) and motor dysfunction (130 s. vs 150 s.) in mice, as determined by Morris water maze and rotarod test, respectively. Golgi staining of cortical pyramidal neurons revealed that, compared to the controls, the CCI group treated with vehicle solution had significantly lower values of dendritic order (or dendritic branch number) (4.0 vs 6.2), total spine length (400 µm vs 620 µm) and spine density (40 spines/µm vs 60 spines/µm), but had significantly higher values of dendritic beading (40 beadings/mm vs 20 beadings/mm). Additionally, Sholl analysis showed that, compared to controls, the CCI + NS group mice had significantly lower values of dendritic intersections (1.0 vs 2.0). Immunofluorescence assay also revealed that, compared to controls, the CCI + NS group mice had significantly higher values of the newly formed hippocampal cells (1250/mm2 vs 1000/mm2) but significantly lower values of dendritic order (2.0 branch # vs 4.2 branch #), total spine length (180 µm vs 320 µm) and intersection (1.0 vs 3.0). The CCI + NS group mice further showed significantly higher numbers of microglia in the dentate gyrus of the hippocampus and higher concentrations of pro-inflammatory cytokines in the cerebrospinal fluids. All the CCI-induced spatial memory (40 s) and motor (150 s) dysfunction, deranged dendritic and spine morphology of cortical pyramidal neurons or hippocampal newly formed cells, hippocampal microgliosis, and central neuroinflammation were all significantly reduced by melatonin administration during post-CCI. Simultaneously, melatonin therapy caused an enhancement in the compensatory hippocampal neurogenesis and neurotrophic growth factors (e.g., doublecortin-1) and compensatory central anti-inflammatory cytokines. Our results indicate that melatonin attenuates the spatial memory and motor deficits via the modification of cortical and hippocampal dendritic spine morphology, hippocampal microgliosis and neurogenesis, and neuroinflammation in mice with traumatic brain injury.
Asunto(s)
Lesiones Traumáticas del Encéfalo/tratamiento farmacológico , Espinas Dendríticas/efectos de los fármacos , Hipocampo/efectos de los fármacos , Melatonina/farmacología , Corteza Motora/efectos de los fármacos , Neuronas/efectos de los fármacos , Memoria Espacial/efectos de los fármacos , Animales , Modelos Animales de Enfermedad , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Ratones , Ratones Endogámicos C57BLRESUMEN
BACKGROUND: Heat stroke-induced mortality is rising across the globe. So, the design of prophylactic and/or therapeutic modalities for heat stroke is pressing need. The common plant derived flavonoid exhibits strong anti-oxidant and anti-inflammatory activities; however, its effects in heat stroke remain unknown. The study aimed to investigate the cardioprotective effects of myricetin on heat stroke induced acute myocardial injury as well as lethality in rats and to explore the underlying mechanisms. METHODS: Myocardial injury was induced by subjecting the anesthetized rats to a high ambient temperature of 43 °C for 70 min. An intragastrical dose of myricetin (5-25 mg/kg body weight) was given to rats once per day for one week prior to the start of heat stress. Heat shock protein 72 antibodies was given intraperitoneally to rats 24 h before the start of heat stress. Myocardial injury severity was estimated by determing myocardial damage scores, myocardial injury indicators, myocardial oxidative and inflammatory factors. Western blot analysis was used for cardiac expression of heat shock protein (HSP)72. RESULTS: Significant (P < 0.05) up-regulation of HSP-72 after chronic administration of myricetin coincided with significant (P < 0.05) reduction in hyperthermia, hypotension, cardiac inflammatory and oxidative damage and lethality. Inhibition of HSP-72 showed a significant (P < 0.05) reversal in the cardiaprotection as well as survival. CONCLUSIONS: Our results indicate that myricetin diminishes myocardial injury as well as lethality in heat stroke by up-regulating HSP-72 and show promise as a novel prevention therapeutic for heat stroke.
Asunto(s)
Flavonoides/farmacología , Proteínas del Choque Térmico HSP72/genética , Lesiones Cardíacas/prevención & control , Golpe de Calor/tratamiento farmacológico , Animales , Cardiotónicos/administración & dosificación , Cardiotónicos/farmacología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Flavonoides/administración & dosificación , Lesiones Cardíacas/etiología , Golpe de Calor/complicaciones , Masculino , Miocardio/patología , Ratas , Ratas Sprague-Dawley , Regulación hacia ArribaRESUMEN
OBJECTIVES: PCR-based typing of the emm gene Streptococcus pyogenes often results in the amplification of multiple bands. This has resulted in the misclassification of strains into types based on non-emm gene sequences. We aimed to improve the specificity of the emm typing PCR reaction using a primer called CDC3, the sequence for which has been previously used to identify emm genes in silico. METHODS: The proposed primer CDC3 was validated in silico from a global database of 1688 GAS genomes and in vitro with 32 isolates. PCR reactions were performed on genomic DNA from each isolate, using the published CDC1 forward primer with the CDC2 reverse primer or the new CDC3 reverse primer. The products were examined by gel electrophoresis, and representative PCR products were sequenced. RESULTS: In 1688 S. pyogenes genomes, the previous CDC2 reverse primer annealed in silico in 1671 emm genes and also in 2109 non emm genes in close proximity, whereas the new CDC3 primer annealed in 1669 emm genes only. The remaining 19 genes without a CDC3 binding site were chimeric emm genes. The PCR pair CDC1+CDC3 produced a single band at appropriate molecular weight in all 32 isolates tested, while the CDC1+CDC2 pair produced more than one band in 13 of 32 isolates (40%). CONCLUSIONS: The new CDC3 primer is more specific for emm genes than the previous CDC2 primer and represents a simple solution to reduce the potential for mistyping S. pyogenes strains.
Asunto(s)
Antígenos Bacterianos/genética , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas Portadoras/genética , Tipificación Molecular/métodos , Streptococcus pyogenes/clasificación , Técnicas de Tipificación Bacteriana , Simulación por Computador , Cartilla de ADN/genética , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Streptococcus pyogenes/genética , Streptococcus pyogenes/aislamiento & purificaciónRESUMEN
Decades of focus on selective ion channel blockade has been dismissed as an effective approach to antiarrhythmic drug development. In that context many older antiarrhythmic drugs lacking ion channel selectivity may serve as tools to explore mixed ion channel blockade producing antiarrhythmic activity. This study investigated the non-clinical electrophysiological and antiarrhythmic actions of bisaramil and penticainide using in vitro and in vivo methods. In isolated cardiac myocytes both drugs directly block sodium currents with IC50 values of 13µM (bisaramil) and 60µM (penticainide). Both drugs reduced heart rate but prolonged the P-R, QRS and Q-T intervals of the ECG (due to sodium and potassium channel blockade) in intact rats. They reduced cardiac conduction velocity in isolated rat hearts, increased the threshold currents for capture and fibrillation (indices of sodium channel blockade) and reduced the maximum following frequency as well as prolonged the effective refractory period (indices of potassium channel blockade) of electrically stimulated rat hearts. Both drugs reduced ventricular arrhythmias and eliminated mortality due to VF in ischemic rat hearts. The index of cardiac electrophysiological balance (iCEB) did not change significantly over the dose range evaluated; however, different drug effects resulted when changes in BP and HR were considered. While bisaramil is a more potent sodium channel blocker compared to penticainide, both produce a spectrum of activity against ventricular arrhythmias due to mixed cardiac ion channel blockade. Antiarrhythmic drugs exhibiting mixed ion channel blockade may serve as tools for development of safer mixed ion channel blocking antiarrhythmic drugs.
Asunto(s)
Antiarrítmicos/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Clorobencenos/farmacología , Frecuencia Cardíaca/efectos de los fármacos , Bloqueadores de los Canales de Potasio/farmacología , Propilaminas/farmacología , Piridinas/farmacología , Bloqueadores de los Canales de Sodio/farmacología , Animales , Antiarrítmicos/química , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Células Cultivadas , Clorobencenos/química , Relación Dosis-Respuesta a Droga , Frecuencia Cardíaca/fisiología , Masculino , Técnicas de Cultivo de Órganos , Bloqueadores de los Canales de Potasio/química , Canales de Potasio/fisiología , Propilaminas/química , Piridinas/química , Ratas , Ratas Sprague-Dawley , Bloqueadores de los Canales de Sodio/química , Canales de Sodio/fisiologíaRESUMEN
BACKGROUND: RSD921, the R,R enantiomer of the kappa (k) agonist PD117,302, lacks significant activity on opioid receptors. METHODS: The pharmacological and toxicological actions were studied with reference to cardiovascular, cardiac, antiarrhythmic, toxic and local anaesthetic activity. RESULTS: In rats, dogs and baboons, RSD921 dose-dependently reduced blood pressure and heart rate. In a manner consistent with sodium channel blockade it prolonged the PR and QRS intervals of the ECG. Furthermore, in rats and NHP, RSD921 increased the threshold currents for induction of extra-systoles and ventricular fibrillation (VFt), and prolonged effective refractory period (ERP). In rats, RSD921 was protective against arrhythmias induced by electrical stimulation and coronary artery occlusion. Application of RSD921 to voltage-clamped rat cardiac myocytes blocked sodium currents. RSD921 also blocked transient (ito) and sustained (IKsus) outward potassium currents, albeit with reduced potency relative to sodium current blockade. Sodium channel blockade due to RSD921 in myocytes and isolated hearts was enhanced under ischaemic conditions (low pH and high extracellular potassium concentration). When tested on the cardiac, neuronal and skeletal muscle forms of sodium channels expressed in Xenopus laevis oocytes, RSD921 produced equipotent tonic block of sodium currents, enhanced channel block at reduced pH (6.4) and marked use-dependent block of the cardiac isoform. RSD921 had limited but quantifiable effects in subacute toxicology studies in rats and dogs. Pharmacokinetic analyses were performed in baboons. Plasma concentrations producing cardiac actions in vivo after intravenous administration of RSD921 were similar to the concentrations effective in the in vitro assays utilized. CONCLUSIONS: RSD921 primarily blocks sodium currents, and possesses antiarrhythmic and local anaesthetic activity.
Asunto(s)
Anestésicos Locales/farmacología , Antiarrítmicos/farmacología , Arritmias Cardíacas/prevención & control , Frecuencia Cardíaca/efectos de los fármacos , Miocitos Cardíacos/efectos de los fármacos , Pirroles/farmacología , Bloqueadores de los Canales de Sodio/farmacología , Canales de Sodio/efectos de los fármacos , Tiofenos/farmacología , Potenciales de Acción , Administración Intravenosa , Anestésicos Locales/administración & dosificación , Anestésicos Locales/farmacocinética , Anestésicos Locales/toxicidad , Animales , Antiarrítmicos/administración & dosificación , Antiarrítmicos/farmacocinética , Antiarrítmicos/toxicidad , Antihipertensivos/farmacología , Arritmias Cardíacas/etiología , Arritmias Cardíacas/metabolismo , Arritmias Cardíacas/fisiopatología , Presión Sanguínea/efectos de los fármacos , Modelos Animales de Enfermedad , Perros , Relación Dosis-Respuesta a Droga , Femenino , Cobayas , Humanos , Inyecciones Intradérmicas , Preparación de Corazón Aislado , Masculino , Ratones , Miocitos Cardíacos/metabolismo , Conducción Nerviosa/efectos de los fármacos , Umbral del Dolor/efectos de los fármacos , Papio , Ratas , Ratas Sprague-Dawley , Bloqueadores de los Canales de Sodio/administración & dosificación , Bloqueadores de los Canales de Sodio/farmacocinética , Bloqueadores de los Canales de Sodio/toxicidad , Canales de Sodio/metabolismo , Factores de Tiempo , Xenopus laevisRESUMEN
Food allergy is an increasing problem for those affected, their families or carers, the food industry and for regulators. The food supply chain is highly vulnerable to fraud involving food allergens, risking fatalities and severe reputational damage to the food industry. Many facets are being pursued to ameliorate the difficulties including better food labelling and the concept of thresholds of elicitation of allergy symptoms as risk management tools. These efforts depend to a high degree on the ability reliably to detect and quantify food allergens; yet all current analytical approaches exhibit severe deficiencies that jeopardise accurate results being produced particularly in terms of the risks of false positive and false negative reporting. If we fail to realise the promise of current risk assessment and risk management of food allergens through lack of the ability to measure food allergens reproducibly and with traceability to an international unit of measurement, the analytical community will have failed a significant societal challenge. Three distinct but interrelated areas of analytical work are urgently needed to address the substantial gaps identified: (a) a coordinated international programme for the production of properly characterised clinically relevant reference materials and calibrants for food allergen analysis; (b) an international programme to widen the scope of proteomics and genomics bioinformatics for the genera containing the major allergens to address problems in ELISA, MS and DNA methods; (c) the initiation of a coordinated international programme leading to reference methods for allergen proteins that provide results traceable to the SI. This article describes in more detail food allergy, the risks of inapplicable or flawed allergen analyses with examples and a proposed framework, including clinically relevant incurred allergen concentrations, to address the currently unmet and urgently required analytical requirements. Support for the above recommendations from food authorities, business organisations and National Measurement Institutes is important; however transparent international coordination is essential. Thus our recommendations are primarily addressed to the European Commission, the Health and Food Safety Directorate, DG Santé. A global multidisciplinary consortium is required to provide a curated suite of data including genomic and proteomic data on key allergenic food sources, made publically available on line.
Asunto(s)
Alérgenos/análisis , Análisis de los Alimentos/métodos , Abastecimiento de Alimentos , Salud , Animales , Humanos , RiesgoRESUMEN
This study characterized the antiarrhythmic effects of the opioid receptor antagonist naloxone in rats subject to electrically induced and ischemic arrhythmias. Naloxone (2, 8 and 32 µmol/kg/min) was examined on heart rate, blood pressure, and the electrocardiogram (EKG) as well as for effectiveness against arrhythmias produced by occlusion of the left anterior descending coronary artery or electrical stimulation of the left ventricle. Naloxone reduced blood pressure at the highest dose tested while heart rate was dose-dependently reduced. Naloxone dose-dependently prolonged the P-R and QRS intervals and increased the RSh amplitude indicative of effects on cardiac sodium (Na) channels. Naloxone prolonged the Q-T interval suggesting a delay in repolarization. Naloxone effects were comparable to the comparator quinidine. Naloxone (32 µmol/kg/min) reduced ventricular fibrillation (VF) incidence to 38% (from 100% in controls). This same dose significantly increased the threshold for induction of ventricular fibrillation (VFt), prolonged the effective refractory period (ERP) and reduced the maximal following frequency (MFF). The patterns of ECG changes, reduction in ischemic arrhythmia (VF) incidence and changes in electrically induced arrhythmia parameters at high doses of naloxone suggest that it directly blocks cardiac Na and potassium (K) ion channels.
Asunto(s)
Antiarrítmicos/uso terapéutico , Arritmias Cardíacas/tratamiento farmacológico , Naloxona/uso terapéutico , Disfunción Ventricular/tratamiento farmacológico , Animales , Presión Sanguínea/efectos de los fármacos , Vasos Coronarios/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Electrocardiografía/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Ventrículos Cardíacos , Masculino , Isquemia Miocárdica/tratamiento farmacológico , Isquemia Miocárdica/fisiopatología , Quinidina/farmacología , Ratas , Ratas Sprague-Dawley , Periodo Refractario Electrofisiológico/efectos de los fármacos , Canales de Sodio/efectos de los fármacos , Fibrilación Ventricular/prevención & controlRESUMEN
Novel anticancer drugs targeting key apoptosis regulators have been developed and are undergoing clinical trials. Pharmacodynamic biomarkers to define the optimum dose of drug that provokes tumor apoptosis are in demand; acquisition of longitudinal tumor biopsies is a significant challenge and minimally invasive biomarkers are required. Considering this, we have developed and validated a preclinical 'death-switch' model for the discovery of secreted biomarkers of tumour apoptosis using in vitro proteomics and in vivo evaluation of the novel imaging probe [(18)F]ML-10 for non-invasive detection of apoptosis using positron emission tomography (PET). The 'death-switch' is a constitutively active mutant caspase-3 that is robustly induced by doxycycline to drive synchronous apoptosis in human colorectal cancer cells in vitro or grown as tumor xenografts. Death-switch induction caused caspase-dependent apoptosis between 3 and 24 hours in vitro and regression of 'death-switched' xenografts occurred within 24 h correlating with the percentage of apoptotic cells in tumor and levels of an established cell death biomarker (cleaved cytokeratin-18) in the blood. We sought to define secreted biomarkers of tumor apoptosis from cultured cells using Discovery Isobaric Tag proteomics, which may provide candidates to validate in blood. Early after caspase-3 activation, levels of normally secreted proteins were decreased (e.g. Gelsolin and Midkine) and proteins including CD44 and High Mobility Group protein B1 (HMGB1) that were released into cell culture media in vitro were also identified in the bloodstream of mice bearing death-switched tumors. We also exemplify the utility of the death-switch model for the validation of apoptotic imaging probes using [(18)F]ML-10, a PET tracer currently in clinical trials. Results showed increased tracer uptake of [(18)F]ML-10 in tumours undergoing apoptosis, compared with matched tumour controls imaged in the same animal. Overall, the death-switch model represents a robust and versatile tool for the discovery and validation of apoptosis biomarkers.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Caspasa 3/metabolismo , Animales , Antineoplásicos/uso terapéutico , Biomarcadores/sangre , Neoplasias Colorrectales/diagnóstico por imagen , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/metabolismo , Citocinas/metabolismo , Doxorrubicina/farmacología , Doxorrubicina/uso terapéutico , Gelsolina/metabolismo , Proteína HMGB1/metabolismo , Células HT29 , Humanos , Queratina-18/sangre , Ratones , Ratones SCID , Midkina , Tomografía de Emisión de Positrones , Proteómica , Radiografía , Radiofármacos , Trasplante HeterólogoRESUMEN
BACKGROUND: Expression of microRNAs (miRs) has been shown to be altered in many solid tumours and is being explored in melanoma. The malignant potential of some melanocytic lesions is difficult to predict. We hypothesised that characterisation of miR expression in borderline melanocytic proliferations would lead to the identification of a molecular profile that could be used with known prognostic factors to differentiate lesions with high malignant potential. METHODS: The miR expression profile of melanocytic lesions (benign naevi, malignant melanoma and borderline melanocytic tumours) was evaluated by real-time PCR. RESULTS: PCR analysis revealed primary cutaneous melanomas had an 8.6-fold overexpression of miR-21 and a 7.5-fold overexpression of miR-155 compared with benign naevi (P<0.0001). In situ hybridisation confirmed these results. miR-21 and miR-155 were significantly overexpressed within borderline lesions (P=0.0011 and P=0.0048, respectively). When borderline lesions were categorised by mitotic activity and Breslow thickness, miR-21 was associated with mitotic activity and miR-155 was associated with thickness (P<0.025). Among 14 patients with borderline lesions who underwent sentinel lymph node biopsy (SLNB), positive SLNB was associated with increased miR-21 and miR-155 in the primary lesion compared with lesions with a negative SLNB. CONCLUSION: MicroRNA expression profiles can be used to characterise atypical melanocytic lesions.
Asunto(s)
Melanoma/genética , MicroARNs/genética , Mitosis/fisiología , Nevo de Células Epitelioides y Fusiformes/genética , Nevo Pigmentado/genética , Neoplasias Cutáneas/genética , Humanos , Hibridación in Situ , Melanoma/patología , Índice Mitótico , Nevo de Células Epitelioides y Fusiformes/patología , Nevo Pigmentado/patología , Reacción en Cadena de la Polimerasa , Biopsia del Ganglio Linfático Centinela , Neoplasias Cutáneas/patologíaRESUMEN
OBJECTIVE: Our aim was to compare image quality, coronary segment assessability and radiation dose in prospectively gated axial (PGA) coronary CT angiography (CTA) and conventional retrospectively gated helical (RGH) coronary CTA. METHODS: Institutional review committee approval and informed consent were obtained. RGH CTA was performed in 41 consecutive patients (33 males, 8 females; mean age 52.6 years), then the PGA CTA technique was evaluated in 41 additional patients (24 males, 17 females; mean age 57.3 years) all with a pre-scan heart rate of ≤70 beats per minute (bpm). Two radiologists, blinded to clinical information, independently scored subjective image quality on a five-point ordinal scale. RESULTS: The mean effective dose in the PGA group was 4.7±0.9 mSv, representing a 69% dose reduction compared with the RGH CTA group (15.1±1.9 mSv, p<0.001). The mean segmental image quality score was significantly higher in the PGA group (3.4 vs 3.2) than in the RGH CTA group (p<0.005). The percentage of assessable segments was 98.1% in the PGA group and 97.3% in the RGH group (p = 0.610). CONCLUSION: PGA CTA offers a significant reduction in radiation dose compared with RGH CTA, with comparable image quality for patients with heart rates below 70 bpm.
Asunto(s)
Angiografía Coronaria/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Tomografía Computarizada Espiral/métodos , Electrocardiografía/métodos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Dosis de Radiación , Estudios RetrospectivosRESUMEN
INTRODUCTION: Cough is a common medical problem for which there are few effective drug treatments. A limited understanding of the mechanisms of induction and maintenance of cough and a paucity of suitable animal models frustrate drug discovery efforts to find novel anti-tussives. As in humans, guinea-pigs evoke a cough reflex upon exposure to tussive agents such as citric acid and capsaicin; both of which have been widely used to assess novel anti-tussive drugs. However, the potential for using within-group designs in drug development has received little attention and such designs may offer a way of assisting the drug discovery effort in the area of cough as well as other areas. METHODS: Cough can be monitored in conscious guinea-pigs by placing animals in a Perspex chamber, in which air is continually exchanged by use of negative pressure and drug delivery of aerosols to the chamber can be accurately timed. Cough in response to a tussive agent (e.g. 0.2-0.4M citric acid; 10-30 microM capsaicin) is detected by the simultaneous microphonic recording of audible signals characteristic of the cough response as well as by positive pressure changes in the chamber generated by a cough dependent rapid expiration of air from the lungs. Both the sound and pressure signals are recorded using an online analyzer, whilst the number of coughs can be analyzed off-line. The number of coughs over a 15 min period is used to quantitate tussive events. RESULTS: Reproducible cough can be detected in animals using cross-over designs that lend themselves to drug studies. Both the time and concentration dependence of anti-tussive drug action can be evaluated in the same animal. Furthermore, the effect of different anti-tussive drugs can be evaluated thereby reducing between group error and thereby improving the sensitivity of the test. DISCUSSION: Repeated measures design improves the precision with which to evaluate anti-tussive drugs in preclinical models and could be used to make the drug discovery process more efficient.
Asunto(s)
Antitusígenos/farmacología , Tos/tratamiento farmacológico , Agonistas Adrenérgicos beta/administración & dosificación , Agonistas Adrenérgicos beta/uso terapéutico , Anestésicos Locales/uso terapéutico , Animales , Capsaicina , Enfermedad Crónica , Ácido Cítrico , Tos/inducido químicamente , Tos/patología , Estudios Cruzados , Cobayas , Inyecciones Intraperitoneales , Lidocaína/uso terapéutico , Masculino , Reproducibilidad de los Resultados , Proyectos de Investigación , Soluciones , Sonido , Terbutalina/administración & dosificación , Terbutalina/uso terapéuticoRESUMEN
INTRODUCTION: The optimal timing of breast reconstruction is controversial. Immediate breast reconstruction (IBR) has been gaining in popularity due to the aesthetic and psychological benefits, although its role is less certain when postoperative radiotherapy may be required. There is some evidence that long term cosmetic outcome of IBR using the autologous latissimus dorsi (ALD) flap may be impaired if the reconstruction is subjected to postoperative radiotherapy. We compared the long term cosmetic outcome and patient satisfaction between a group of patients who underwent IBR with postoperative radiotherapy and a group who underwent delayed ALD reconstruction. METHODS: Patients who underwent ALD breast reconstruction between 1997 and 2000 were invited to attend a research clinic. At the clinic up-to-date photographs were obtained and a quality of life questionnaire was completed. Cosmetic outcome was assessed by a panel of judges including surgeons, nurses and lay people. RESULTS: Thirteen patients who had IBR and postoperative radiotherapy and 11 patients who had delayed reconstruction attended for follow up. In the long term both groups fell within an acceptable cosmetic outcome range. However, there was a trend towards a better outcome in patients undergoing delayed reconstruction, with the volume and contour of the upper pole being most affected in the irradiated reconstructions. Patient satisfaction was similar between the two groups, however most patients in retrospect would have preferred an immediate reconstruction. CONCLUSIONS: Immediate ALD breast reconstruction, even in the setting of postoperative radiotherapy, yields satisfactory results. We continue to offer it to patients undergoing mastectomy operations, even when postoperative radiotherapy is likely to be required.