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System Effects (system + effects)
Kinds of System Effects Selected AbstractsArea Postrema And Sympathetic Nervous System Effects Of Vasopressin And Angiotensin IICLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2000Eileen M Hasser SUMMARY 1. Precise control over the cardiovascular system requires the integration of both neural and humoral signals related to blood volume and blood pressure. Humoral signals interact with neural systems, modulating their control over the efferent mechanisms that ultimately determine the level of pressure and volume. 2. Peptide hormones such as angiotensin (Ang)II and arginine vasopressin (AVP) act through circumventricular organs (CVO) to influence cardiovascular regulation. 3. The area postrema (AP), a CVO in the brainstem, mediates at least some of the central actions of these peptides. Vasopressin appears to act in the AP to cause sympathoinhibition and a shift in baroreflex control of the sympathetic nervous system (SNS) to lower pressures. These effects of AVP and the AP appear to be mediated by ,2 -adrenoceptor and glutamatergic mechanisms in the nucleus tractus solitarius. 4. In contrast to AVP AngII has effects in the AP to blunt baroreflex control of heart rate and cause sympathoexcitation. The effects of chronic AngII to increase activity of the SNS may be due to AP-dependent activation of neurons in the rostral ventrolateral medulla. [source] Antiepileptic Drugs in the Management of Cluster Headache and Trigeminal NeuralgiaHEADACHE, Issue 2001Todd D. Rozen MD Cluster headache and trigeminal neuralgia are relatively rare but debilitating neurologic conditions. Although they are clinically and diagnostically distinct from migraine, many of the same pharmacologic agents are used in their management. For many patients, the attacks are so frequent and severe that abortive therapy is often ineffective; therefore, chronic preventive therapy is necessary for adequate pain control. Cluster headache and trigeminal neuralgia have several distinguishing clinical features. Cluster headache is predominantly a male disorder; trigeminal neuralgia is more prevalent in women. Individuals with cluster headaches often develop their first attack before age 25; most patients with trigeminal neuralgia are between age 50 and 70. Cluster headaches are strongly associated with tobacco smoking and triggered by alcohol consumption; trigeminal neuralgia can be triggered by such stimuli as shaving and toothbrushing. Although the pain in both disorders is excruciating, cluster headache pain is episodic and unilateral, typically surrounds the eye, and lasts 15 to 180 minutes; the pain of trigeminal neuralgia lasts just seconds and is usually limited to the tissues overlying the maxillary and mandibular divisions of the trigeminal nerve. Cluster headache is unique because of its associated autonomic symptoms. Although the pathophysiology of cluster headache and trigeminal neuralgia are not completely understood, both appear to have central primary processes, and these findings have prompted investigations of the effectiveness of the newer antiepileptic drugs for cluster headache prevention and for the treatment of trigeminal neuralgia. The traditional antiepileptic drugs phenytoin and carbamazepine have been used for the treatment of trigeminal neuralgia for a number of years, and while they are effective, they can sometimes cause central nervous system effects such as drowsiness, ataxia, somnolence, and diplopia. Reports of studies in small numbers of patients or individual case studies indicate that the newer antiepileptic drugs are effective in providing pain relief for trigeminal neuralgia and cluster headache sufferers, with fewer central nervous system side effects. Divalproex has been shown to provide effective pain control and to reduce cluster headache frequency by more than half in episodic and chronic cluster headache sufferers. Topiramate demonstrated efficacy in a study of 15 patients, with a mean time to induction of cluster headache remission of 1.4 weeks (range, 1 day to 3 weeks). In the treatment of trigeminal neuralgia, gabapentin has been shown to be effective in an open-label study. When added to an existing but ineffective regimen of carbamazepine or phenytoin, lamotrigine provided improved pain relief; it also may work as monotherapy. Topiramate provided a sustained analgesic effect when administered to patients with trigeminal neuralgia. The newer antiepileptic drugs show considerable promise in the management of cluster headache and trigeminal neuralgia. [source] New once-daily formulation for trospium in overactive bladderINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 11 2010C. Chapple Summary Aims:, We examined the relative efficacy and safety of trospium 20 mg bid and 60 mg extended release formulations and position this drug against other antimuscarinic agents. Methods:, Data were identified on the pharmacology and pharmacokinetics of trospium chloride. Key publications on trospium 20-mg and 60-mg clinical studies in patients with overactive bladder (OAB) were identified and efficacy and safety compared between these formulations as well as other antimuscarinic agents. Results:, Trospium offers the principal advantage over other antimuscarinic agents that, as it is a quaternary amine, it does not cross the blood,brain barrier and is therefore less likely to cause central nervous system effects observed with several other agents. Moreover, with its minimal liver metabolisation, independent of the main cytochrome pathways, trospium has a low risk of drug,drug interaction in patients taking multiple pharmacological agents. Trospium 60 mg ER is as effective as trospium 20 mg bid in improving the key outcome parameters associated with OAB, but with a lower rate of dry mouth, the most common side effect of these agents. Trospium has comparable efficacy and safety to the other antimuscarinic agents currently marketed. Discussion:, Good patient persistence with treatment has been reported with trospium. There are currently a large number of antimuscarinic drugs on the market without clear evidence to distinguish one agent from another in terms of efficacy, provided that an adequate dose is used in the clinical setting. Conclusion:, The new formulation of trospium is certainly worth considering as a pharmacological treatment of patients with OAB, particularly in the elderly, in whom one wants to avoid the potential for cognitive dysfunction. [source] Implications of system expansion for the assessment of well-to-wheel CO2 emissions from biomass-based transportationINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2010Elisabeth Wetterlund Abstract In this paper we show the effects of expanding the system when evaluating well-to-wheel (WTW) CO2 emissions for biomass-based transportation, to include the systems surrounding the biomass conversion system. Four different cases are considered: DME via black liquor gasification (BLG), methanol via gasification of solid biomass, lignocellulosic ethanol and electricity from a biomass integrated gasification combined cycle (BIGCC) used in a battery-powered electric vehicle (BPEV). All four cases are considered with as well as without carbon capture and storage (CCS). System expansion is used consistently for all flows. The results are compared with results from a conventional WTW study that only uses system expansion for certain co-product flows. It is shown that when expanding the system, biomass-based transportation does not necessarily contribute to decreased CO2 emissions and the results from this study in general indicate considerably lower CO2 mitigation potential than do the results from the conventional study used for comparison. It is shown that of particular importance are assumptions regarding future biomass use, as by expanding the system, future competition for biomass feedstock can be taken into account by assuming an alternative biomass usage. Assumptions regarding other surrounding systems, such as the transportation and the electricity systems are also shown to be of significance. Of the four studied cases without CCS, BIGCC with the electricity used in a BPEV is the only case that consistently shows a potential for CO2 reduction when alternative use of biomass is considered. Inclusion of CCS is not a guarantee for achieving CO2 reduction, and in general the system effects are equivalent or larger than the effects of CCS. DME from BLG generally shows the highest CO2 emission reduction potential for the biofuel cases. However, neither of these options for biomass-based transportation can alone meet the needs of the transport sector. Therefore, a broader palette of solutions, including different production routes, different fuels and possibly also CCS, will be needed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Improved Turnover Numbers in Palladium-Catalyzed Bisdiene Cyclization-Trapping using N-Heterocyclic Carbene LigandsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 15 2005James Abstract An optimized palladium-N-heterocyclic carbene catalyst system effects the palladium-catalyzed bisdiene cyclization-trapping with phenol at the 0.01% catalyst loading level with a TON of 7.6×103 and TOF of 280,h,1, values much higher than typically found for this and related carbocyclizations. The reaction scales well and the trans -substituted six-membered ring product is obtained in excellent yield on a 10-mmole scale without further optimization of the catalyst system or reaction conditions. [source] Fracture risk associated with the use of morphine and opiatesJOURNAL OF INTERNAL MEDICINE, Issue 1 2006P. VESTERGAARD Abstract. Objectives., To study the effect of morphine and opiates on fracture risk. Design., Case,control study. Setting., Nationwide register-based study. Subjects., Cases were all subjects with any fracture sustained during the year 2000 (n = 124 655). For each case, three controls (n = 373 962) matched on age and gender were randomly drawn from the background population. The primary exposure variables were use of morphine and opiates. Morphine and other opiates had been used by 10 015 (8.0%) of the case subjects and 12 108 (3.2%) of the controls. Adjustments were made for several confounders including prior fracture, and use of weak analgesics [nonsteroidal anti-inflammatory drugs, acetylsalicylic acid (ASA) and acetaminophene]. The effect of dose was examined by stratifying for cumulated dose (defined daily dose). Main outcome measure., Fracture. Results., Morphine (1.47, 95% CI 1.37,1.58), fentanyl (2.23, 95% CI 1.89,2.64), methadone (1.39, 95% CI 1.05,1.83), oxycodone (1.36, 95% CI 1.08,1.69), nicomorphine (1.57, 95% CI 1.38,1.78), ketobemidone (1.07, 95% CI 1.02,1.13), tramadol (1.54, 95% CI 1.49,1.58) and codeine (1.16, 95% CI 1.12,1.20) were all associated with an increase in overall fracture risk. No increase was present for buprenorphine (0.86, 95% CI 0.79,0.95), pethidine (0.98, 95% CI 0.89,1.08), dextropropoxiphene (1.02, 95% CI 0.90,1.16), and combinations of ASA and codeine (0.94, 95% CI 0.88,1.01). Conclusions., An increased fracture risk is seen in users of morphine and opiates. The reason for this may be related to the risk of falls due to central nervous system effects such as dizziness. [source] Relevant activities of extracts and constituents of animals used in traditional Chinese medicine for central nervous system effects associated with Alzheimer's diseaseJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2006Yuhao Ren The centipede Scolopendra subspinipes mutilans L. Koch (,Wugong'), the beetle Mylabris phalerata Pallas (,Ban mao') and the earthworm Pheretima aspergillum Chen (,DiLong') have a reputation in traditional Chinese medicine for reducing symptoms of central nervous system decline, including memory loss. A series of extracts of all three organisms was tested for acetylcholinesterase (AChE) inhibition and copper ion binding effects, the latter likely to reduce oxidative damage caused by excess copper. The beetle and centipede chloroform extracts showed the strongest AChE inhibitory effects (30.6% inhibition at 105 ,g mL,1 and 32.3% inhibition at 167 ,g mL,1, respectively) and, in the case of the centipede, this was traced to the unsaturated fatty acids present using bioassay-guided fractionation. Cantharidin from the beetle was shown to have AChE activity (31% inhibition at 1 ,M, 0.196,g mL,1), making it a major contributor to the activity of the beetle extract. The earthworm showed no AChE inhibitory activity. Since unsaturated fatty acids have not been previously reported to have AChE inhibitory activity, a series of related compounds was tested to determine structure-activity relationships. It was found that activity existed where there was a chain length of more than 16 C atoms with at least one unsaturated bond in the chain. The carboxylic acid group was also necessary for activity. The fatty acids present in the centipede also showed the ability to bind copper ions when tested using a novel thin layer chromatography method designed to detect copper-binding compounds. The activities reported give some support to the use of the beetle and centipede in traditional Chinese medicine for improving cognitive function. [source] Botulinum toxins in neurological diseaseMUSCLE AND NERVE, Issue 5 2004Cynthia L. Comella MD Abstract Botulinum toxins are among the most potent neurotoxins known to humans. In the past 25 years, botulinum toxin has emerged as both a potential weapon of bioterrorism and as a powerful therapeutic agent, with growing applications in neurological and non-neurological disease. Botulinum toxin is unique in its ability to target peripheral cholinergic neurons, preventing the release of acetylcholine through the enzymatic cleavage of proteins involved in membrane fusion, without prominent central nervous system effects. There are seven serotypes of the toxin, each with a specific activity at the molecular level. Currently, serotypes A (in two preparations) and B are available for clinical use, and have been shown to be safe and effective for the treatment of dystonia, spasticity, and other disorders in which muscle overactivity gives rise to symptoms. This review focuses on the pharmacology, electrophysiology, immunology, and application of botulinum toxin in selected neurological disorders. Muscle Nerve 29: 628,644, 2004 [source] Central nervous system effects of natural and synthetic glucocorticoidsPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 5 2009Pierluigi Fietta MD Natural glucocorticoids (NGC) physiologically modulate body homeostasis and coordinate adaptive responses to stress, involving almost all organs and tissues, including brain. Since their therapeutic availability, synthetic GC (SGC) have been successfully prescribed for a variety of diseases. Mounting evidence, however, demonstrated pleiotropic adverse effects (AE), including central nervous system (CNS) disturbances, which are often misdiagnosed or underestimated. The aim of the present study was therefore to review and discuss the CNS effects of both NGC and SGC. A detailed search was carried out of the available literature using the PubMed (US National Library of Medicine) database. Cortisolemia plays a crucial role in control of behavior, cognition, mood, and early life programming of stress reactivity. Hypercortisolemia or SGC treatments may induce behavioral, psychic and cognitive disturbances, due to functional and, over time, structural alterations in specific brain target areas. These AE are generally dose and time dependent (infrequent at prednisone-equivalent doses <20 mg/day) and usually reversible. Pediatric patients are particularly susceptible. Behavioral changes, including feeding and sleeping modifications, are common. Psychic AE are unpredictable and heterogeneous, usually mild/moderate, severe in 5,10% of cases. Manic symptoms have been mostly associated with short SGC courses, and depressive disorder with long-term treatments. Suicidality has been reported. Cognitive AE peculiarly affect declarative memory performance. Physiologic levels of NGC are essential for efficient brain functions. Otherwise, hypercortisolemia and SGC treatments may cause dose-/time-dependent neuropsychic AE and, over time, structural alterations in brain target areas. Clinicians should carefully monitor patients, especially children and/or when administering high doses SGC. [source] Managing precipitation use in sustainable dryland agroecosystemsANNALS OF APPLIED BIOLOGY, Issue 2 2004GARY A PETERSON Summary In the Great Plains of North America potential evaporation exceeds precipitation during most months of the year. About 75% of the annual precipitation is received from April through September, and is accompanied by high temperatures and low relative humidity. Dryland agriculture in the Great Plains has depended on wheat production in a wheat-fallow agroecosystem (one crop year followed by a fallow year). Historically this system has used mechanical weed control practices during the fallow period, which leaves essentially no crop residue cover for protection against soil erosion and greatly accelerates soil organic carbon oxidation. This paper reviews the progress made in precipitation management in the North American Great Plains and synthesises data from an existing long-term experiment to demonstrate the management principles involved. The long-term experiment was established in 1985 to identify dryland crop and soil management systems that would maximize precipitation use efficiency (maximization of biomass production per unit of precipitation received), improve soil productivity, and increase economic return to the farmers in the West Central portion of the Great Plains. Embedded within the primary objective are sub-objectives that focus on reducing the amount of summer fallow time and reversing the soil degradation that has occurred in the wheat-fallow cropping system. The experiment consists of four variables: 1) Climate regime; 2) Soils; 3) Management systems; and 4) Time. The climate variable is based on three levels of potential evapotranspiration (ET), which are represented by three sites in eastern Colorado. All sites have annual long-term precipitation averages of approximately 400,450 mm, but vary in growing season open pan evaporation from 1600 mm in the north to 1975 mm in the south. The soil variable is represented by a catenary sequence of soils at each site. Management systems, the third variable, differ in the amount of summer fallow time and emphasize increased crop diversity. All systems are managed with no-till techniques. The fourth variable is time, and the results presented in this paper are for the first 12 yr (3 cycles of the 4-yr system). Comparing yields of cropping systems that differ in cycle length and systems that contain fallow periods, when no crop is produced, is done with a technique called "annualisation". Yields are "annualised" by summing yields for all crops in the system and dividing by the total number of years in the system cycle. For example in a wheat-fallow system the wheat yield is divided by two because it takes 2 yr to produce one crop. Cropping system intensification increased annualised grain and crop residue yields by 75 to 100% compared to wheat-fallow. Net return to farmers increased by 25% to 45% compared to wheat-fallow. Intensified cropping systems increased soil organic C content by 875 and 1400 kg ha,1, respectively, after 12 yr compared to the wheat-fallow system. All cropping system effects were independent of climate and soil gradients, meaning that the potential for C sequestration exists in all combinations of climates and soils. Soil C gains were directly correlated to the amount of crop residue C returned to the soil. Improved macroaggregation was also associated with increases in the C content of the aggregates. Soil bulk density was reduced by 0.01g cm,3 for each 1000 kg ha,1 of residue addition over the 12-yr period, and each 1000 kg ha,1 of residue addition increased effective porosity by 0.3%. No-till practices have made it possible to increase cropping intensification beyond the traditional wheat-fallow system and in turn water-use efficiency has increased by 30% in West Central Great Plains agroecosystems. Cropping intensification has also provided positive feedbacks to soil productivity via the increased amounts of crop residue being returned to the soil. [source] Dynamic ecosystem models and the evaluation of ecosystem effects of fishing: can we make meaningful predictions?AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 1 2003L.A. Robinson Abstract 1.Fishing is one of the most widespread anthropogenic impacts on marine ecosystems. In recent times, the development of measurable metrics of the resultant ecosystem effects, has become an important aspect of fisheries management. Ecosystem models are often advocated as tools for the evaluation of system effects, but the extent to which models are able to make meaningful predictions, has not yet been fully addressed. 2.In order to assess the suitability of models, to evaluate ecosystem effects of fisheries, the direct and indirect effects were catalogued. 3.From the literature, 33 applications of marine ecosystem models were identified for analysis of their ability to fully assess these catalogued effects. Analysis was possible for only 24 of the models due to poor documentation of the other 9. 4.Each model was examined for their inclusion of nine functional groups, deemed essential for the assessment of impacts of fishing on the whole ecosystem (e.g. detritus, marine mammals). The models were also assessed for their inclusion of several additional factors, either fundamental in the regulation of marine ecosystems (e.g. environmental forcing), or important in the classification of their role as a predictor of changes in ecological processes (e.g. simulation, spatial properties). 5.No model formulation provided coverage in all the areas necessary to cover the identified effects of fisheries. Eight models provided good coverage, nutrient dynamics and benthos were the least well represented aspects of the ecosystem. 6.The ECOPATH with Ecosim family of models, the European Regional Seas Ecosystem Model (ERSEM) and the Anderson & Ursin multispecies extension to the Beverton & Holt model all seem likely to yield good insights. 7.In further developing these models, however, consideration must be given to explicitly incorporate spatial factors and extrinsic forcing functions, such as climate. Copyright © 2002 John Wiley & Sons, Ltd. [source] The long-term impact of bereavement upon spouse health: a 10-year follow-upACTA NEUROPSYCHIATRICA, Issue 5 2010Michael P. Jones Jones MP, Bartrop RW, Forcier L, Penny R. The long-term impact of bereavement upon spouse health: a 10-year follow-up. Objectives: This study is the first to examine the effect of bereavement of a first-degree family member on subsequent morbidity over a 10-year follow-up period. Methods: A sample of bereaved subjects (n = 72) were compared with a control group (n = 80) recruited in the same period with respect to morbidity experience during follow-up. Morbidity events were ascertained from the subject themselves, their health care providers and these sources were also compared. Results: Bereavement was associated with an elevated total burden of illness as well as with mental health and circulatory system categories diagnosed according to the International Classification of Diseases - Clinically Modified (ICD-9) classification system. The elevation ranged from approximately 20% for any illness to 60,100% among circulatory system disorders. Although in an earlier study there was a downregulation of T-cell function in the bereaved during the first 8 weeks, there was no evidence that the bereavement was associated with increased morbidity in the respiratory or immune system ICD-9 categories long-term. Conclusions: Past epidemiological research has indicated that bereavement of a close family member is associated with adverse health consequences of a generalised morbidity. Our study suggests an increase in mental health and circulatory system effects in particular. Further research is required to determine whether other systems are also affected by bereavement. [source] | ||||||||||||||||||||||