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1.
Glob Chang Biol ; 29(18): 5352-5366, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37332117

RESUMEN

Over the past several decades, various trends in vegetation productivity, from increases to decreases, have been observed throughout Arctic-Boreal ecosystems. While some of this variation can be explained by recent climate warming and increased disturbance, very little is known about the impacts of permafrost thaw on productivity across diverse vegetation communities. Active layer thickness data from 135 permafrost monitoring sites along a 10° latitudinal transect of the Northwest Territories, Canada, paired with a Landsat time series of normalized difference vegetation index from 1984 to 2019, were used to quantify the impacts of changing permafrost conditions on vegetation productivity. We found that active layer thickness contributed to the observed variation in vegetation productivity in recent decades in the northwestern Arctic-Boreal, with the highest rates of greening occurring at sites where the near-surface permafrost recently had thawed. However, the greening associated with permafrost thaw was not sustained after prolonged periods of thaw and appeared to diminish after the thaw front extended outside the plants' rooting zone. Highest rates of greening were found at the mid-transect sites, between 62.4° N and 65.2° N, suggesting that more southernly sites may have already surpassed the period of beneficial permafrost thaw, while more northern sites may have yet to reach a level of thaw that supports enhanced vegetation productivity. These results indicate that the response of vegetation productivity to permafrost thaw is highly dependent on the extent of active layer thickening and that increases in productivity may not continue in the coming decades.


Asunto(s)
Ecosistema , Hielos Perennes , Canadá , Territorios del Noroeste , Clima , Regiones Árticas
2.
Crit Care Nurs Q ; 41(3): 253-263, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29851674

RESUMEN

This article addresses the development, implementation, and evaluation of an education program for safe patient handling and mobility at a large academic medical center. The ultimate goal of the program was to increase safety during patient mobility/transfer and reduce nursing staff injury from lifting/pulling. This comprehensive program was designed on the basis of the principles of prework, application, and support at the point of care. A combination of online learning, demonstration, skill evaluation, and coaching at the point of care was used to achieve the goal. Specific roles and responsibilities were developed to facilitate implementation. It took 17 master trainers, 88 certified trainers, 176 unit-based trainers, and 98 coaches to put 3706 nurses and nursing assistants through the program. Evaluations indicated both an increase in knowledge about safe patient handling and an increased ability to safely mobilize patients. The challenge now is sustainability of safe patient-handling practices and the growth and development of trainers and coaches.


Asunto(s)
Implementación de Plan de Salud/métodos , Movimiento y Levantamiento de Pacientes/normas , Personal de Enfermería en Hospital/educación , Seguridad del Paciente/normas , Desarrollo de Programa , Centros Médicos Académicos/organización & administración , Humanos , Capacitación en Servicio/métodos , Sistemas de Atención de Punto
3.
Adv Pharmacol ; 99: 251-286, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38467483

RESUMEN

In this review, we critically evaluate the contribution of prodrugs to treating two related psychiatric disorders, attention-deficit hyperactivity disorder (ADHD) and binge-eating disorder (BED). ADHD is characterized by inattentiveness, distractibility, impulsiveness, and hyperactivity. BED is also an impulse-control disorder which leads to frequent, compulsive episodes of excessive eating (binges). Lisdexamfetamine (LDX; prodrug of d-amphetamine) is approved to treat both ADHD and BED. Serdexmethylphenidate (SDX; prodrug of d-threo-methylphenidate) is not clinically approved as monotherapy but, in a fixed-dose combination with immediate release d-threo-methylphenidate (Azstarys™), SDX is approved for managing ADHD in children/adolescents. The pharmacological actions of a stimulant mediate both its efficacy and side-effects. Therefore, daily management of ADHD or BED to maintain optimum efficacy and tolerability places highly restrictive requirements on the pharmacokinetic/pharmacodynamic (PK/PD) characteristics of stimulant medications, especially prodrugs. Prodrugs must have good bioavailability and rapid metabolism to provide therapeutic efficacy soon after morning dosing combined with providing stimulant coverage throughout the day/evening. A wide selection of dosages and linear PK for the prodrug and its active metabolite are essential requirements for treatment of these conditions. The proposed neurobiological causes of ADHD and BED are described. The chemical, pharmacological and PK/PD properties responsible for the therapeutic actions of the prodrugs, LDX and SDX, are compared and contrasted. Finally, we critically assess their contribution as ADHD and BED medications, including advantages over their respective active metabolites, d-amphetamine and d-threo-methylphenidate, and also their potential for misuse and abuse.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Trastorno por Atracón , Estimulantes del Sistema Nervioso Central , Metilfenidato , Profármacos , Adolescente , Niño , Humanos , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Trastorno por Atracón/tratamiento farmacológico , Estimulantes del Sistema Nervioso Central/uso terapéutico , Dextroanfetamina/uso terapéutico , Metilfenidato/uso terapéutico , Profármacos/farmacología , Profármacos/uso terapéutico
4.
Front Psychiatry ; 15: 1322434, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38915848

RESUMEN

Various countries and US States have legalized cannabis, and the use of the psychoactive1 and non-psychoactive cannabinoids is steadily increasing. In this review, we have collated evidence from published non-clinical and clinical sources to evaluate the abuse, dependence and associated safety risks of the individual cannabinoids present in cannabis. As context, we also evaluated various synthetic cannabinoids. The evidence shows that delta-9 tetrahydrocannabinol (Δ9-THC) and other psychoactive cannabinoids in cannabis have moderate reinforcing effects. Although they rapidly induce pharmacological tolerance, the withdrawal syndrome produced by the psychoactive cannabinoids in cannabis is of moderate severity and lasts from 2 to 6 days. The evidence overwhelmingly shows that non-psychoactive cannabinoids do not produce intoxicating, cognitive or rewarding properties in humans. There has been much speculation whether cannabidiol (CBD) influences the psychoactive and potentially harmful effects of Δ9-THC. Although most non-clinical and clinical investigations have shown that CBD does not attenuate the CNS effects of Δ9-THC or synthetic psychoactive cannabinoids, there is sufficient uncertainty to warrant further research. Based on the analysis, our assessment is cannabis has moderate levels of abuse and dependence risk. While the risks and harms are substantially lower than those posed by many illegal and legal substances of abuse, including tobacco and alcohol, they are far from negligible. In contrast, potent synthetic cannabinoid (CB1/CB2) receptor agonists are more reinforcing and highly intoxicating and pose a substantial risk for abuse and harm. 1 "Psychoactive" is defined as a substance that when taken or administered affects mental processes, e.g., perception, consciousness, cognition or mood and emotions.

5.
Neuropharmacology ; 257: 110037, 2024 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-38876309

RESUMEN

Kappa opioid receptors (KORs) are implicated in the pathophysiology of various psychiatric and neurological disorders creating interest in targeting the KOR system for therapeutic purposes. Accordingly, navacaprant (NMRA-140) is a potent, selective KOR antagonist being evaluated as a treatment for major depressive disorder. In the present report, we have extended the pharmacological characterization of navacaprant by further demonstrating its selective KOR antagonist properties and confirming its lack of agonist activity at KORs and related targets involved in opioid-related abuse. Using CHO-K1 cells expressing human KOR, mu (MOR), or delta (DOR) opioid receptors, navacaprant demonstrated selective antagonist properties at KOR (IC50 = 0.029 µM) versus MOR (IC50 = 3.3 µM) and DOR (IC50 > 10 µM) in vitro. In vivo, navacaprant (10-30 mg/kg, i.p.) dose-dependently abolished KOR-agonist induced analgesia in the mouse tail-flick assay. Additionally, navacaprant (10, 30 mg/kg, p.o.) significantly reduced KOR agonist-stimulated prolactin release in mice and rats, confirming KOR antagonism in vivo. Navacaprant showed no agonist activity at any opioid receptor subtype (EC50 > 10 µM) in vitro and exhibited no analgesic effect in the tail-flick assays at doses ≤100 mg/kg, p.o. thereby confirming a lack of opioid receptor agonist activity in vivo. Importantly, navacaprant did not alter extracellular dopamine concentrations in the nucleus accumbens shell of freely-moving rats following doses ≤100 mg/kg, p.o., whereas morphine (10, 20 mg/kg, i.p.) significantly increased dopamine levels. These results demonstrate that navacaprant is a KOR-selective antagonist with no pharmacological properties implicated in opioid-related abuse.


Asunto(s)
Analgésicos Opioides , Cricetulus , Receptores Opioides kappa , Receptores Opioides kappa/agonistas , Receptores Opioides kappa/antagonistas & inhibidores , Animales , Células CHO , Humanos , Masculino , Ratones , Ratas , Analgésicos Opioides/farmacología , Cricetinae , Trastornos Relacionados con Opioides/tratamiento farmacológico , Antagonistas de Narcóticos/farmacología , Relación Dosis-Respuesta a Droga , Ratas Sprague-Dawley , Receptores Opioides delta/antagonistas & inhibidores , Receptores Opioides delta/agonistas , Receptores Opioides mu/agonistas , Receptores Opioides mu/antagonistas & inhibidores , Núcleo Accumbens/efectos de los fármacos , Núcleo Accumbens/metabolismo , Ratones Endogámicos C57BL , Dopamina/metabolismo
6.
J Psychopharmacol ; 37(1): 33-44, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36588452

RESUMEN

BACKGROUND: Psychedelics are an increasingly active area of research and pharmaceutical development. This includes abuse potential assessment to better understand their pharmacological mechanisms and effects and guide controlled substance regulation. Psychedelics pose challenges to abuse assessments to ensure valid, reliable, and generalizable outcomes and safe study conduct. FINDINGS: Key nonclinical techniques, for example, receptor binding and functional assays in vitro, and nonclinical physical dependence determinations, are easily adaptable to psychedelics. However, the entactogens (weak reinforcers) and hallucinogens (non-reinforcers) require more flexible approaches than typically recommended by regulatory agencies. Phase 1 pharmacokinetic/pharmacodynamic safety studies and Phases 2/3 efficacy/safety trials with systematic monitoring of abuse-related adverse events are readily applicable to psychedelics. Human abuse trials require modification because supratherapeutic doses may not be safe and procedures, for example, personal monitors to manage serious adverse events, might bias outcomes. RECOMMENDATIONS: Abuse-related studies for psychedelics requiring approval by Food and Drug Administration and other agencies should take into consideration existing knowledge that will vary from extensive, for example, psilocybin, to zero for novel hallucinogens and entactogens. Many abuse assessments can be reasonably applied to animals and humans without compromising scientific integrity. Modification of existing techniques and incorporating a broader range of nonclinical tests should ensure generalizable outcomes. Human abuse studies merit reconsideration and possible modification to ensure safety and validity for psychedelic drug evaluation. Other nonclinical and clinical methods can provide evaluations of the pharmacological equivalence of test drugs to known drugs of abuse to provide context to the abuse assessment and guide drug scheduling.


Asunto(s)
Alucinógenos , Trastornos Relacionados con Sustancias , Animales , Humanos , Estados Unidos , Alucinógenos/efectos adversos , Sustancias Controladas , Psilocibina/farmacología , Trastornos Relacionados con Sustancias/tratamiento farmacológico , Dietilamida del Ácido Lisérgico/farmacología
7.
Breast Cancer Res Treat ; 132(1): 197-203, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22113254

RESUMEN

Breast conservation therapy (BCT) consisting of lumpectomy and postoperative radiation has become an accepted alternative to mastectomy (MRM) for the treatment of early stage breast cancer. We currently report the 25 year outcomes of a single institution, prospective, randomized clinical trial at the National Cancer Institute. 237 women with pathologically confirmed invasive breast tumors 5 cm or less were accrued between 1979 and 1987 and randomized to receive either BCT or MRM. Overall survival was the primary endpoint. Patients with node positive disease were included and treated with doxorubicin and cyclophosphamide. Both arms received axillary dissection. BCT patients had radiation to the whole breast followed by a boost. At a median follow-up of 25.7 years, overall survival was 43.8% for the MRM group and 37.9% for BCT (P = 0.38). Although the cumulative incidence of a disease-free survival event was higher in BCT patients (29.0% MRM vs. 56.4% BCT, P = 0.0017), the additional treatment failures were primarily isolated ipsilateral breast tumor recurrences (IBTR's) requiring salvage mastectomy. 22.3% of BCT patients experienced an IBTR. Distant disease and second cancers were similar in both arms. After 25 years, long term survival between BCT and MRM continues to be similar in patients treated for early stage breast cancer. Patients receiving BCT may be at risk for additional treatment-related morbidity, which may occur as a late event. Further studies are required to delineate patients at higher risk for these events, and prolonged follow up should be encouraged after treatment for all women.


Asunto(s)
Neoplasias de la Mama/cirugía , Recurrencia Local de Neoplasia , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/radioterapia , Terapia Combinada , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Estimación de Kaplan-Meier , Mastectomía Radical Modificada , Mastectomía Segmentaria , Persona de Mediana Edad , National Cancer Institute (U.S.) , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Resultado del Tratamiento , Estados Unidos
8.
Handb Exp Pharmacol ; (212): 135-64, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23129331

RESUMEN

Antipsychotic drugs, particularly second-generation antipsychotics (SGAs), have reduced the burden to society of schizophrenia, but many still produce excessive weight gain. A significant number of SGAs also act directly to impair glycemic control causing insulin resistance, impaired glucose tolerance and type 2 diabetes, and also rarely diabetic ketoacidosis (DKA). Schizophrenia itself is almost certainly causal in many endocrine and metabolic disturbances, making this population especially vulnerable to the adverse metabolic consequences of treatment with SGAs. Hence, there is an urgent need for a new generation of antipsychotic drugs that provide efficacy equal to the best of the SGAs without their liability to cause weight gain or type 2 diabetes. In the absence of such safe and effective alternatives to the SGAs, there is a substantial clinical need for the introduction of new antipsychotics without adverse metabolic effects and new antiobesity drugs to combat these metabolic side effects. We discuss the adverse metabolic consequences of schizophrenia, its exacerbation by a lack of social care, and the additional burden placed on patients by their medication. A critical evaluation of the animal models of antipsychotic-induced metabolic disturbances is provided with observations on their strengths and limitations. Finally, we discuss novel antipsychotic drugs with a lower propensity to increase metabolic risk and adjunctive medications to mitigate the adverse metabolic actions of the current generation of antipsychotics.


Asunto(s)
Antipsicóticos/efectos adversos , Diabetes Mellitus/inducido químicamente , Cetoacidosis Diabética/inducido químicamente , Obesidad/inducido químicamente , Animales , Peso Corporal/efectos de los fármacos , Diabetes Mellitus/metabolismo , Cetoacidosis Diabética/metabolismo , Humanos , Células Secretoras de Insulina/efectos de los fármacos , Modelos Animales , Obesidad/metabolismo
9.
Curr Top Behav Neurosci ; 57: 79-126, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35507283

RESUMEN

Since the landmark MTA (Multimodal Treatment of ADHD) trial unequivocally demonstrated the efficacy of methylphenidate, catecholaminergic drugs, especially stimulants, have been the therapeutic mainstay in treatment of Attention-Deficit Hyperactivity Disorder (ADHD). We review the new drugs which have entered the ADHD formulary. The lessons learned from drug-candidates that have succeeded in clinical trials together with those that have not have also been considered. What emerges confirms and consolidates the hypothesis that clinically effective ADHD drugs indirectly or directly increase catecholaminergic neurotransmission in the prefrontal cortex (PFC). Attempts to enhance catecholaminergic signalling through modulatory neurotransmitter systems or cognitive-enhancing drugs have all failed. New drugs approved for ADHD are catecholaminergic reuptake inhibitors and releasing agents, or selective noradrenaline reuptake inhibitors. Triple reuptake inhibitors with preferential effects on dopamine have not been successful. The substantial number of failures probably accounts for a continued focus on developing novel catecholaminergic and noradrenergic drugs, and a dearth of drug-candidates with novel mechanisms entering clinical development. However, substantial improvements in ADHD pharmacotherapy have been achieved by the almost exclusive use of once-daily medications and prodrugs, e.g. lisdexamfetamine and Azstarys®, which improve compliance, deliver greater efficacy and reduce risks for diversion and abuse.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Estimulantes del Sistema Nervioso Central , Metilfenidato , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Estimulantes del Sistema Nervioso Central/farmacología , Estimulantes del Sistema Nervioso Central/uso terapéutico , Humanos , Metilfenidato/uso terapéutico , Investigación
10.
J Psychopharmacol ; 36(6): 680-703, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-34318734

RESUMEN

BACKGROUND: Binge-eating disorder (BED) is a common psychiatric condition with adverse psychological and metabolic consequences. Lisdexamfetamine (LDX) is the only approved BED drug treatment. New drugs to treat BED are urgently needed. METHODS: A comprehensive review of published psychopathological, pharmacological and clinical findings. RESULTS: The evidence supports the hypothesis that BED is an impulse control disorder with similarities to ADHD, including responsiveness to catecholaminergic drugs, for example LDX and dasotraline. The target product profile (TPP) of the ideal BED drug combines treating the psychopathological drivers of the disorder with an independent weight-loss effect. Drugs with proven efficacy in BED have a common pharmacology; they potentiate central noradrenergic and dopaminergic neurotransmission. Because of the overlap between pharmacotherapy in attention deficit hyperactivity disorder (ADHD) and BED, drug-candidates from diverse pharmacological classes, which have already failed in ADHD would also be predicted to fail if tested in BED. The failure in BED trials of drugs with diverse pharmacological mechanisms indicates many possible avenues for drug discovery can probably be discounted. CONCLUSIONS: (1) The efficacy of drugs for BED is dependent on reducing its core psychopathologies of impulsivity, compulsivity and perseveration and by increasing cognitive control of eating. (2) The analysis revealed a large number of pharmacological mechanisms are unlikely to be productive in the search for effective new BED drugs. (3) The most promising areas for new treatments for BED are drugs, which augment noradrenergic and dopaminergic neurotransmission and/or those which are effective in ADHD.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Trastorno por Atracón , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Trastorno por Atracón/tratamiento farmacológico , Humanos , Dimesilato de Lisdexanfetamina/uso terapéutico , Neurofarmacología , Pérdida de Peso
11.
J Psychopharmacol ; 35(10): 1204-1215, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33691518

RESUMEN

BACKGROUND: α7 Nicotinic acetylcholine receptors are implicated in the reinstatement of drug-seeking, an important component of relapse. We showed previously that the α7 nicotinic acetylcholine receptor antagonist, methyllycaconitine, specifically attenuated morphine-primed reinstatement of conditioned place preference in rodents and this effect was mediated in the ventral hippocampus. AIMS: The purpose of this study was to evaluate α7 nicotinic acetylcholine receptor antagonism in reinstatement of the conditioned place preference for the more widely abused opioid, heroin, and to compare the effect of α7 nicotinic acetylcholine receptor blockade on reinstatement of heroin-seeking and heroin self-administration in an intravenous self-administration model of addictive behaviour. METHODS: Rats were trained to acquire heroin conditioned place preference or heroin self-administration; both followed by extinction of responding. Methyllycaconitine or saline was given prior to reinstatement of drug-primed conditioned place preference, or drug-prime plus cue-induced reinstatement of intravenous self-administration, using two protocols: without delivery of heroin in response to lever pressing to model heroin-seeking, or with heroin self-administration, using fixed and progressive ratio reward schedules, to model relapse. RESULTS: Methyllycaconitine had no effect on acquisition of heroin conditioned place preference or lever-pressing for food rewards. Methyllycaconitine blocked reinstatement of heroin-primed conditioned place preference. Methyllycaconitine did not prevent drug-prime plus cue-induced reinstatement of heroin-seeking, reinstatement of heroin self-administration, or diminish the reinforcing effect of heroin. CONCLUSIONS: The α7 nicotinic acetylcholine receptor antagonist, methyllycaconitine, prevented reinstatement of the opioid conditioned place preference, consistent with a role for α7 nicotinic acetylcholine receptors in the retrieval of associative memories of drug liking. The lack of effect of methyllycaconitine in heroin-dependent rats in two intravenous self-administration models suggests that α7 nicotinic acetylcholine receptors do not play a role in later stages of heroin abuse.


Asunto(s)
Aconitina/análogos & derivados , Dependencia de Heroína/fisiopatología , Heroína/administración & dosificación , Receptor Nicotínico de Acetilcolina alfa 7/antagonistas & inhibidores , Aconitina/farmacología , Animales , Conducta Adictiva/fisiopatología , Condicionamiento Psicológico/efectos de los fármacos , Señales (Psicología) , Comportamiento de Búsqueda de Drogas/fisiología , Extinción Psicológica/efectos de los fármacos , Masculino , Antagonistas Nicotínicos/farmacología , Ratas , Ratas Sprague-Dawley , Ratas Wistar , Refuerzo en Psicología , Recompensa , Autoadministración , Receptor Nicotínico de Acetilcolina alfa 7/metabolismo
12.
Br J Clin Pharmacol ; 68(6): 861-74, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20002080

RESUMEN

Obesity is a major cause of morbidity and mortality through cardio- and cerebrovascular diseases and cancer. The metabolic consequences of obesity include dyslipidaemia, hypertension, proinflammatory atherogenesis, pre-diabetes and Type 2 diabetes. For a significant proportion of patients, pharmacotherapy to tackle obesity is required as adjunctive support to diet, exercise and lifestyle modification. To this end, the pharmaceutical industry is pursuing many novel drug targets. Although this view is probably not justified, the recent tribulations of rimonabant have created a perception that the regulatory bar for the approval of antiobesity drugs has been raised. Although >5% of placebo-subtracted weight loss maintained over 1 year is the primary efficacy end-point, it is improvements in cardiovascular risk factors that the Food and Drug Administration (FDA) and European Medicines Agency (EMEA) require to grant approval. Safety aspects are also critical in this indication. Many companies are now switching development of their antiobesity drug candidates into other metabolic disorders. Type 2 diabetes is accepted by the industry and FDA, but not EMEA, as the most appropriate alternative. On the other hand, improvements in plasma lipids produced by antiobesity drugs are moderate compared with established therapies, suggesting dyslipidaemia is not a viable development option. Metabolic Syndrome is not accepted by FDA or EMEA as a discrete disease and the agencies will not licence antiobesity drugs for its treatment. The regulatory environment for antiobesity drugs and the spectrum of indications for which they can be approved could change dramatically if positive data for sibutramine emerge from the SCOUT outcome trial.


Asunto(s)
Fármacos Antiobesidad/uso terapéutico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Síndrome Metabólico/tratamiento farmacológico , Obesidad/tratamiento farmacológico , Adulto , Niño , Aprobación de Drogas/legislación & jurisprudencia , Diseño de Fármacos , Drogas en Investigación/uso terapéutico , Femenino , Humanos , Masculino , Factores de Riesgo , Adulto Joven
13.
Ambio ; 38(5): 266-71, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19714959

RESUMEN

The physical environment of the Canadian North is particularly sensitive to changes in climate because of a large concentration of cryospheric elements including both seasonal and multiyear forms of freshwater and sea ice, permafrost, snow, glaciers, and small ice caps. Because the cryosphere responds directly to changes in air temperature and precipitation, it is a primary indicator of the effects of climate variability and change. This article reviews the major changes that have occurred in the recent historical record of these cryospheric components at high latitudes in Canada. Some changes have been less pronounced in the Canadian North than elsewhere, such as changes in sea-ice coverage, whereas others have been potentially more significant, such as ablation of the extensive alpine and high-Arctic small glaciers and ice caps. Projections of future changes are also reviewed for each cryospheric component. Discussion about two other physical components of the North intrinsically linked to the cryosphere is also included, specifically: i) freshwater discharge to the Arctic Ocean via major river networks that are fed primarily by various forms of snow and ice, and ii) the related rise in sea level, which is strongly influenced by ablation of the cryosphere, and coastal stability, which also depends on the thermal integrity of coastal permafrost.


Asunto(s)
Clima , Cubierta de Hielo , Regiones Árticas , Canadá , Ecosistema , Predicción , Agua Dulce , Northern Territory , Nieve
14.
Ambio ; 38(5): 272-81, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19714960

RESUMEN

Northern Canada is projected to experience major changes to its climate, which will have major implications for northern economic development. Some of these, such as mining and oil and gas development, have experienced rapid expansion in recent years and are likely to expand further, partly as the result of indirect effects of changing climate. This article reviews how a changing climate will affect several economic sectors including the hydroelectric, oil and gas, and mining industries as well as infrastructure and transportation, both marine and freshwater. Of particular importance to all sectors are projected changes in the cryosphere, which will create both problems and opportunities. Potential adaptation strategies that could be used to minimize the negative impacts created by a climate change are also reviewed.


Asunto(s)
Clima , Industria Procesadora y de Extracción , Cubierta de Hielo , Transportes/métodos , Regiones Árticas , Canadá , Conservación de los Recursos Energéticos , Aceites Combustibles , Gasolina , Minería , Northern Territory
15.
J Psychopharmacol ; 33(3): 383-391, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30676189

RESUMEN

BACKGROUND: Samidorphan is a novel µ-opioid antagonist with low intrinsic activity at κ- and δ-opioid receptors. AIMS: Because samidorphan is central nervous system-active, we investigated whether samidorphan (13.6, 40.8, 68 µg/kg/injection) served as a positive reinforcer in rats trained to self-administer heroin on a fixed ratio-5 schedule. Samidorphan's relative reinforcing effect was evaluated by progressive ratio/break-point determination. Naltrexone (13.6, 40.8, 68 µg/kg/injection) and heroin (7.5, 15, 25 µg/kg/injection) were comparators. RESULTS: All heroin doses maintained self-administration on fixed ratio-5 and progressive ratio/break-points at levels significantly greater than saline. Samidorphan and naltrexone had similar profiles on fixed ratio-5 with one samidorphan dose serving as a positive reinforcer and one naltrexone dose showing a strong trend ( p=0.053) for positive reinforcement. The numbers of injections of every samidorphan and naltrexone dose were significantly lower than all heroin doses. The numbers of self-administered samidorphan and naltrexone injections/session on fixed ratio-5 were not significantly different from one another. The mean inter-injection intervals for heroin were significantly shorter than for saline, whereas those of samidorphan and naltrexone were not. Progressive ratio break-points for samidorphan and naltrexone were not different from saline except for the highest dose of samidorphan. In addition, the progressive ratio break-points for samidorphan were not significantly different from those of naltrexone and were significantly lower than heroin. The samidorphan unit-doses evaluated in self-administration yielded plasma concentrations ranging between 25-109% and 10-45% of the maximum concentration values in humans. CONCLUSIONS: Overall, the profiles of samidorphan and naltrexone, which has no abuse liability, were similar in this model.


Asunto(s)
Heroína/administración & dosificación , Naltrexona/análogos & derivados , Antagonistas de Narcóticos/administración & dosificación , Esquema de Refuerzo , Administración Intravenosa , Animales , Relación Dosis-Respuesta a Droga , Masculino , Naltrexona/administración & dosificación , Naltrexona/farmacología , Antagonistas de Narcóticos/farmacología , Ratas , Ratas Sprague-Dawley , Receptores Opioides/efectos de los fármacos , Receptores Opioides/metabolismo , Refuerzo en Psicología , Autoadministración
16.
Nat Commun ; 10(1): 264, 2019 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-30651568

RESUMEN

Permafrost warming has the potential to amplify global climate change, because when frozen sediments thaw it unlocks soil organic carbon. Yet to date, no globally consistent assessment of permafrost temperature change has been compiled. Here we use a global data set of permafrost temperature time series from the Global Terrestrial Network for Permafrost to evaluate temperature change across permafrost regions for the period since the International Polar Year (2007-2009). During the reference decade between 2007 and 2016, ground temperature near the depth of zero annual amplitude in the continuous permafrost zone increased by 0.39 ± 0.15 °C. Over the same period, discontinuous permafrost warmed by 0.20 ± 0.10 °C. Permafrost in mountains warmed by 0.19 ± 0.05 °C and in Antarctica by 0.37 ± 0.10 °C. Globally, permafrost temperature increased by 0.29 ± 0.12 °C. The observed trend follows the Arctic amplification of air temperature increase in the Northern Hemisphere. In the discontinuous zone, however, ground warming occurred due to increased snow thickness while air temperature remained statistically unchanged.

17.
Neuropharmacology ; 142: 89-115, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-29427652

RESUMEN

Psychedelics comprise drugs come from various pharmacological classes including 5-HT2A agonists, indirect 5-HT agonists, e.g., MDMA, NMDA antagonists and κ-opioid receptor agonists. There is resurgence in developing psychedelics to treat psychiatric disorders with high unmet clinical need. Many, but not all, psychedelics are schedule 1 controlled drugs (CDs), i.e., no approved medical use. For existing psychedelics in development, regulatory approval will require a move from schedule 1 to a CD schedule for drugs with medical use, i.e., schedules 2-5. Although abuse of the psychedelics is well documented, a systematic preclinical and clinical evaluation of the risks they pose in a medical-use setting does not exist. We describe the non-clinical tests required for a regulatory evaluation of abuse/dependence risks, i.e., drug-discrimination, intravenous self-administration and physical dependence liability. A synopsis of the existing data for the various types of psychedelics is provided and we describe our findings with psychedelic drugs in these models. FDA recently issued its guidance on abuse/dependence evaluation of drug-candidates (CDER/FDA, 2017). We critically review the guidance, discuss the impact this document will have on non-clinical abuse/dependence testing, and offer advice on how non-clinical abuse/dependence experiments can be designed to meet not only the expectations of FDA, but also other regulatory agencies. Finally, we offer views on how these non-clinical tests can be refined to provide more meaningful information to aid the assessment of the risks posed by CNS drug-candidates for abuse and physical dependence. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.


Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Evaluación de Medicamentos/métodos , Alucinógenos/efectos adversos , Alucinógenos/uso terapéutico , Trastornos Relacionados con Sustancias/prevención & control , Animales , Humanos
18.
J Plankton Res ; 38(2): 305-316, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27275032

RESUMEN

A variety of ecological strategies for tolerance of low-oxygen conditions within the Costa Rica Dome (CRD) area of the Eastern Tropical Pacific are documented for the copepod family Eucalanidae. During the summer of 2010, we compared the ecological strategies used by the Eucalanidae inside and outside the central CRD region. We compared the vertical and horizontal distributions of five species, Eucalanus inermis, Subeucalanus subtenuis, Subeucalanus subcrassus, Subeucalanus pileatus and Pareucalanus attenuatus together with Rhincalanus species, in the epipelagic (upper 200 m) among four locations, which we grouped into a section roughly crossing the core CRD area (inside-outside core CRD). The coastal area outside the CRD supported the most diverse assemblage, whereas overall abundance of Eucalanidae in the central CRD was 2-fold greater than outside and dominated by E. inermis (>60%). Eucalanidae in the central CRD had a shallow depth distribution, closely associated with the shallow thermocline (10-20 m). There was no evidence of daily vertical migration in the central CRD, but E. inermis demonstrated vertical migration outside the CRD. The vertical abundance patterns of Eucalanidae in the CRD region reflect complex interactions between subtle physical-chemical differences and food resources.

19.
Shock ; 46(3 Suppl 1): 37-41, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27496599

RESUMEN

Despite being the leading cause of death in the United States for individuals 46 years and younger and the primary cause of death among military service members, trauma care research has been underfunded for the last 50 years. Sustained federal funding for a coordinated national trauma clinical research program is required to advance the science of caring for the injured. The Department of Defense is committed to funding studies with military relevance; therefore, it cannot fund pediatric or geriatric trauma clinical trials. Currently, trauma clinical trials are often performed within a single site or a small group of trauma hospitals, and research data are not available for secondary analysis or sharing across studies. Data-sharing platforms encourage transfer of research data and knowledge between civilian and military researchers, reduce redundancy, and maximize limited research funding. In collaboration with the Department of Defense, trauma researchers formed the Coalition for National Trauma Research (CNTR) in 2014 to advance trauma research in a coordinated effort. CNTR's member organizations are the American Association for the Surgery of Trauma (AAST), the American College of Surgeons Committee on Trauma (ACS COT), the Eastern Association for the Surgery of Trauma (EAST), the Western Trauma Association (WTA), and the National Trauma Institute (NTI). CNTR advocates for sustained federal funding for a multidisciplinary national trauma research program to be conducted through a large clinical trials network and a national trauma research repository. The initial advocacy and research activities underway to accomplish these goals are presented.


Asunto(s)
Investigación Biomédica/economía , Investigación Biomédica/organización & administración , Heridas y Lesiones , Investigación Biomédica/estadística & datos numéricos , Agencias Gubernamentales/estadística & datos numéricos , Humanos , Estados Unidos
20.
J Trauma Acute Care Surg ; 81(3): 548-54, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27054514

RESUMEN

BACKGROUND: To increase trauma-related research and elevate trauma on the national research agenda, the National Trauma Institute (NTI) issued calls for proposals, selected funding recipients, and coordinated 16 federally funded (Department of Defense) trauma research awards over a 4-year period. We sought to collect and describe the lessons learned from this activity to inform future researchers of barriers and facilitators. METHODS: Fifteen principal investigators participated in semistructured interviews focused on study management issues such as securing institutional approvals, screening and enrollment, multisite trials management, project funding, staffing, and institutional support. NTI Science Committee meeting minutes and study management data were included in the analysis. Simple descriptive statistics were generated and textual data were analyzed for common themes. RESULTS: Principal investigators reported challenges in obtaining institutional approvals, delays in study initiation, screening and enrollment, multisite management, and study funding. Most were able to successfully resolve challenges and have been productive in terms of scholarly publications, securing additional research funding, and training future trauma investigators. CONCLUSION: Lessons learned in the conduct of the first two funding rounds managed by NTI are instructive in four key areas: regulatory processes, multisite coordination, adequate funding, and the importance of an established research infrastructure to ensure study success. Recommendations for addressing institution-related and investigator-related challenges are discussed along with ongoing advocacy efforts to secure sustained federal funding of a national trauma research program commensurate with the burden of injury.


Asunto(s)
Academias e Institutos , Proyectos de Investigación , Apoyo a la Investigación como Asunto , Traumatología , Humanos , Entrevistas como Asunto , Estados Unidos
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