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Many Conditions (many + condition)
Selected AbstractsConceptualization of mild cognitive impairment: a reviewINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 4 2004Heather S. Davis Abstract Background Several factors have prompted renewed interest in the concept of declines in cognitive function that occur in association with aging, in particular the area between normal cognition and dementia. We review the changing conceptualization of what has come to be known as mild cognitive impairment (MCI) in an effort to identify recent developments and highlight areas of controversy. Methods Standard MEDLINE search for relevant English-language publications on mild cognitive impairment and its associated terms, supplemented by hand searches of pertinent reference lists. Results Many conditions cause cognitive impairment which does not meet current criteria for dementia. Within this heterogenous group, termed ,Cognitive Impairment, No Dementia' (CIND), there are disorders associated with an increased risk of progression to dementia. Still, the conceptualization of these latter disorders remains in flux, with variability around assumptions about aging, the relationship between impairment and disease, and how concomitant functional impairment is classified. Amongst patients with MCI, especially its amnestic form, many will progress to Alzheimer's disease (AD). In contrast with clinic-based studies, where progression is more uniform, population-based studies suggest that the MCI classification is unstable in that context. In addition to Amnestic Mild Cognitive Impairment (AMCI), other syndromes exist and can progress to dementia. For example, an identifiable group with vascular cognitive impairment without dementia shows a higher risk of progression to vascular dementia, Alzheimer's disease and mixed dementia. Conclusions Recent attempts to profile patients at an increased risk of dementia suggest that this can be done in skilled hands, especially in people whose symptoms prompt them to seek medical attention. Whether these people actually have early AD remains to be determined. The more narrowly defined MCI profiles need to be understood in a population context of CIND. Copyright © 2004 John Wiley & Sons, Ltd. [source] Lifespan extension by conditions that inhibit translation in Caenorhabditis elegansAGING CELL, Issue 1 2007Malene Hansen Summary Many conditions that shift cells from states of nutrient utilization and growth to states of cell maintenance extend lifespan. We have carried out a systematic lifespan analysis of conditions that inhibit protein synthesis. We find that reducing the levels of ribosomal proteins, ribosomal-protein S6 kinase or translation-initiation factors increases the lifespan of Caenorhabditis elegans. These perturbations, as well as inhibition of the nutrient sensor target of rapamycin (TOR), which is known to increase lifespan, all increase thermal-stress resistance. Thus inhibiting translation may extend lifespan by shifting cells to physiological states that favor maintenance and repair. Interestingly, different types of translation inhibition lead to one of two mutually exclusive outputs, one that increases lifespan and stress resistance through the transcription factor DAF-16/FOXO, and one that increases lifespan and stress resistance independently of DAF-16. Our findings link TOR, but not sir-2.1, to the longevity response induced by dietary restriction (DR) in C. elegans, and they suggest that neither TOR inhibition nor DR extends lifespan simply by reducing protein synthesis. [source] Hierarchical Logistic Regression: Accounting for Multilevel Data in DIF DetectionJOURNAL OF EDUCATIONAL MEASUREMENT, Issue 3 2010Brian F. French The purpose of this study was to examine the performance of differential item functioning (DIF) assessment in the presence of a multilevel structure that often underlies data from large-scale testing programs. Analyses were conducted using logistic regression (LR), a popular, flexible, and effective tool for DIF detection. Data were simulated using a hierarchical framework, such as might be seen when examinees are clustered in schools, for example. Both standard and hierarchical LR (accounting for multilevel data) approaches to DIF detection were employed. Results highlight the differences in DIF detection rates when the analytic strategy matches the data structure. Specifically, when the grouping variable was within clusters, LR and HLR performed similarly in terms of Type I error control and power. However, when the grouping variable was between clusters, LR failed to maintain the nominal Type I error rate of .05. HLR was able to maintain this rate. However, power for HLR tended to be low under many conditions in the between cluster variable case. [source] Induction and Maintenance of Ethanol Self-Administration in Cynomolgus Monkeys (Macaca fascicularis): Long-Term Characterization of Sex and Individual DifferencesALCOHOLISM, Issue 8 2001J. A. Vivian Background: Investigations of oral ethanol self-administration in nonhuman primates have revealed important parallels with human alcohol use and abuse, yet many fundamental questions concerning the individual risk to, and the biological basis of, excessive ethanol consumption remain unanswered. Moreover, many conditions of access to ethanol in nonhuman primate research are largely unexplored. This set of experiments extends within- and across-session exposure to ethanol to more fully characterize individual differences in oral ethanol self-administration. Methods: Eight male and eight female adult cynomolgus monkeys (Macaca fascicularis) were exposed to daily oral ethanol self-administration sessions for approximately 9 months. During the first 3 months, a fixed-time (FT) schedule of food delivery was used to induce the consumption of an allotted dose of ethanol in 16-hr sessions. Subsequently, the FT schedule was suspended, and ethanol was available ad libitum for 6 months in 16- or 22-hr sessions. Results: Cynomolgus monkeys varied greatly in their propensity to self-administer ethanol, with sex and individual differences apparent within 10 days of ethanol exposure. Over the last 3 months of ethanol access, individual average ethanol intakes ranged from 0.6 to 4.0 g/kg/day, resulting in blood ethanol concentrations from 5 to 235 mg/dl. Males drank approximately 1.5-fold more than females. In addition, heavy-, moderate-, and light-drinking phenotypes were identified by using daily ethanol intake and the percentage of daily calories obtained from ethanol as criteria. Conclusions: Cynomolgus monkeys displayed a wide intersubject range of oral ethanol self-administration with a procedure that used a uniform and prolonged induction that restricted early exposure to ethanol and subsequently allowed unlimited access to ethanol. There were sex and stable individual differences in the propensity of monkeys to consume ethanol, indicating that this species will be important in characterizing risk factors associated with heavy-drinking phenotypes. [source] The effects of low level laser irradiation on osteoblastic cellsORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 1 2001A. R. Coombe Low level laser therapy has been used in treating many conditions with reports of multiple clinical effects including promotion of healing of both hard and soft tissue lesions. Low level laser therapy as a treatment modality remains controversial, however. The effects of wavelength, beam type, energy output, energy level, energy intensity, and exposure regime of low level laser therapy remain unexplained. Moreover, no specific therapeutic window for dosimetry and mechanism of action has been determined at the level of individual cell types. The aim of this study was to investigate the effects of low level laser irradiation on the human osteosarcoma cell line, SAOS-2. The cells were irradiated as a single or daily dose for up to 10 days with a GaAlAs continuous wave diode laser (830 nm, net output of 90 mW, energy levels of 0.3, 0.5, 1, 2, and 4 Joules). Cell viability was not affected by laser irradiation, with the viability being greater than 90% for all experimental groups. Cellular proliferation or activation was not found to be significantly affected by any of the energy levels and varying exposure regimes investigated. Low level laser irradiation did result in a heat shock response at an energy level of 2 J. No significant early or late effects of laser irradiation on protein expression and alkaline phosphatase activity were found. Investigation of intracellular calcium concentration revealed a tendency of a transient positive change after irradiation. Low level laser irradiation was unable to stimulate the osteosarcoma cells utilised for this research at a gross cell population level. The heat shock response and increased intracellular calcium indicate that the cells do respond to low level laser irradiation. Further research is required, utilising different cell and animal models, to more specifically determine the effects of low level laser irradiation at a cellular level. These effects should be more thoroughly investigated before low level laser therapy can be considered as a potential accelerator stimulus for orthodontic tooth movement. [source] Crystallization and preliminary X-ray crystallographic analysis of the trimer core from measles virus fusion proteinACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2003Jieqing Zhu Two heptad-repeat regions (HR1 and HR2) are highly conserved in paramyxovirus fusion proteins and form a stable helical trimer of heterodimers [(HR1,HR2)3] after the fusion between viral and cellular membranes. In this study, two HR regions of the fusion protein of measles virus, a member of the paramyxoviruses, were selected and overexpressed as a single chain (named 2-Helix) connected by an amino-acid linker using a GST-fusion expression system in Escherichia coli. Crystals of 2-Helix protein (GST removed) could be obtained from many conditions using the sitting- or hanging-drop vapour-diffusion method. A complete data set was collected in-house to 1.9,Å resolution from a single crystal. The crystal belongs to space group P6, with unit-cell parameters a = b = 51.637, c = 67.058,Å. To facilitate the crystal structure solution, SeMet-substituted 2-Helix crystals, grown under similar conditions to the native, were also obtained and diffracted X-rays to 1.8,Å using synchrotron radiation. [source] Kinetic modeling of cellulosic biomass to ethanol via simultaneous saccharification and fermentation: Part II.BIOTECHNOLOGY & BIOENGINEERING, Issue 1 2009Experimental validation using waste paper sludge, anticipation of CFD analysis Abstract A kinetic model of cellulosic biomass conversion to ethanol via simultaneous saccharification and fermentation (SSF) developed previously was validated experimentally using paper sludge as the substrate. Adsorption parameters were evaluated based on the data obtained at various values for fractional cellulose conversion. The adsorption model was then combined with batch SSF data to evaluate the cellulose hydrolysis parameters. With the parameters evaluated for the specific substrate, the discrete model was able to predict SSF successfully both with discrete addition of cellulase only and with discrete feeding of substrate, cellulase, and media. The model tested in this study extends the capability of previous SSF models to semi-continuous feeding configurations, and invites a mechanistic interpretation of the recently observed trend of increasing conversion with decreasing feeding frequency [Fan et al. (2007a) Bioprocess Biosyst Eng 30(1):27,34]. Our results also support the feasibility and utility of determining adsorption parameters based on data obtained at several conversions, particularly when the model is to be applied to extended reaction times rather than only initial hydrolysis rates. The revised model is considerably more computationally efficient than earlier models, and appears for many conditions to be within the capability of simulation using computational fluid dynamics. Biotechnol. Bioeng. 2009;102: 66,72. © 2008 Wiley Periodicals, Inc. [source] Piracetam improves mitochondrial dysfunction following oxidative stressBRITISH JOURNAL OF PHARMACOLOGY, Issue 2 2006Uta Keil Mitochondrial dysfunction including decrease of mitochondrial membrane potential and reduced ATP production represents a common final pathway of many conditions associated with oxidative stress, for example, hypoxia, hypoglycemia, and aging. Since the cognition-improving effects of the standard nootropic piracetam are usually more pronounced under such pathological conditions and young healthy animals usually benefit little by piracetam, the effect of piracetam on mitochondrial dysfunction following oxidative stress was investigated using PC12 cells and dissociated brain cells of animals treated with piracetam. Piracetam treatment at concentrations between 100 and 1000 ,M improved mitochondrial membrane potential and ATP production of PC12 cells following oxidative stress induced by sodium nitroprusside (SNP) and serum deprivation. Under conditions of mild serum deprivation, piracetam (500 ,M) induced a nearly complete recovery of mitochondrial membrane potential and ATP levels. Piracetam also reduced caspase 9 activity after SNP treatment. Piracetam treatment (100,500 mg kg,1 daily) of mice was also associated with improved mitochondrial function in dissociated brain cells. Significant improvement was mainly seen in aged animals and only less in young animals. Moreover, the same treatment reduced antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, and glutathione reductase) in aged mouse brain only, which are elevated as an adaptive response to the increased oxidative stress with aging. In conclusion, therapeutically relevant in vitro and in vivo concentrations of piracetam are able to improve mitochondrial dysfunction associated with oxidative stress and/or aging. Mitochondrial stabilization and protection might be an important mechanism to explain many of piracetam's beneficial effects in elderly patients. British Journal of Pharmacology (2006) 147, 199,208. doi:10.1038/sj.bjp.0706459 [source] | |||||||||||||