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Differential Contribution (differential + contribution)
Selected AbstractsDifferential Contribution of Osteoclast- and Osteoblast-Lineage Cells to CpG-Oligodeoxynucleotide (CpG-ODN) Modulation of Osteoclastogenesis,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2005Alla Amcheslavsky Abstract CpG-ODNs modulate osteoclast differentiation through Toll-like receptor 9 (TLR9). Using TLR9-deficient mice, we found that activation of TLR9 on both osteoclast precursors and osteoblasts mediate the osteoclastogenic effect of CpG-ODN. Osteoclastic TLR9 is more important for this activity. Introduction: Bacterial infections cause pathological bone loss by accelerating differentiation and activation of the osteoclast. A variety of bacteria-derived molecules have been shown to enhance osteoclast differentiation through activation of Toll-like receptors (TLRs). We have shown that CpG-oligodeoxynucleotides (CpG-ODNs), mimicking bacterial DNA and exerting their cellular activities through TLR9, modulate osteoclast differentiation in a complex manner: the ODNs inhibit the activity of the physiological osteoclast differentiation factor RANKL in early osteoclast precursors (OCPs) but markedly stimulate osteoclastogenesis in cells primed by RANKL. Materials and Methods: Osteoclast precursors and osteoblasts from TLR9-deficient (TLR9,/,) and wildtype (TLR9+/+) mice were used for in vitro analyses of osteoclast differentiation and modulation of signal transduction and gene expression. Results: As expected CpG-ODN did not exert any activity in cells derived from TLR9,/,mice; these cells, however, responded in a normal manner to other stimuli. Using bone marrow/osteoblasts co-cultures from all possible combinations of TLR9,/, and TLR9+/+ mice-derived cells, we showed that TLR9 in the two lineages is required for CpG-ODN induction of osteoclastogenesis. Conclusions: CpG-ODN modulates osteoclastogenesis in a TLR9-dependent manner. Activation of TLR9 in bone marrow-derived osteoclasts precursors is more crucial to induction of osteoclastogenesis than activation of the osteoblastic TLR9. [source] Differential contributions of the parahippocampal place area and the anterior hippocampus to human memory for scenesHIPPOCAMPUS, Issue 6 2002Stefan Köhler Abstract Past neuroimaging research has identified a parahippocampal place area (PPA) in the posterior medial temporal lobe (MTL), which responds preferentially to visual scenes and plays a role in episodic memory for this class of stimuli. In the present positron emission tomography study, we examined to what extent the functional characteristics of the PPA resemble those of other, more anterior MTL regions across various learning and recognition-memory tasks. We also determined whether the involvement of the PPA in recognition of previously studied scenes is specific to a particular type of scene information. We found that, like the PPA, anterior hippocampal regions showed a novelty response (higher activation for novel than repeated scenes) and a stimulus-related response (higher activation for scenes than objects) during learning, indicating that MTL structures other than the PPA contribute to the encoding of novel stimulus relationships in scenes. However, these anterior hippocampal regions showed no involvement during recognition of either spatial or nonspatial information contained in scenes. The PPA, by contrast, was consistently involved in recognition of all types of scene details, presumably through interactions with co-activated parietal and occipitotemporal cortices. We suggest that MTL contributions from the PPA are sufficient to support recognition of scenes when the task can be based on a perceptually based familiarity process. Hippocampus 2002;12:718,723. © 2002 Wiley-Liss, Inc. [source] Differential contributions of the anterior temporal and medial temporal lobe to the retrieval of memory for person identity informationHUMAN BRAIN MAPPING, Issue 12 2008Takashi Tsukiura Abstract Although previous studies have suggested the importance of the bilateral anterior temporal (ATL) and medial temporal lobes (MTL) in the retrieval of person identity information, there is little evidence concerning how these regions differentially contribute to the process. Here we investigated this question using functional magnetic resonance imaging (fMRI). Before scanning, subjects learned associations among faces (F), names (N), and job titles (as a form of person-related semantics, S). During retrieval with fMRI, subjects were presented with previously learned and new S stimuli, and judged whether the stimuli were old or new. Successful retrieval (H) trials were divided into three conditions: retrieval of S and associated F and N (HSFN); retrieval of S and associated F (HSF); and retrieval of S only (HS). The left ATL was significantly activated in HSFN, compared to HSF or HS, whereas the right ATL and MTL were significantly activated in HSFN and HSF relative to HS. In addition, activity in bilateral ATL was significantly correlated with reaction time for HSFN, whereas we found no significant correlation between activity in the right MTL and reaction time in any condition. The present findings suggest that the left ATL may mediate associations between names and person-related semantic information, whereas the right ATL mediates the association between faces and person-related semantic information in memory for person identity information. In addition, activation of the right MTL region implies that this area may contribute to a more general relational processing of associative components, including memory for person identity information. Hum Brain Mapp 2008. © 2007 Wiley-Liss, Inc. [source] Major and minor depression in Parkinson's disease: a neuropsychological investigationEUROPEAN JOURNAL OF NEUROLOGY, Issue 9 2006A. Costa Previous studies have failed to distinguish the differential contribution of major and minor depression to cognitive impairment in patients with idiopathic Parkinson's disease (PD). This study was aimed at investigating the relationships among major depression (MD), minor depression (MiD) and neuropsychological deficits in PD. Eighty-three patients suffering from PD participated in the study. MD and MiD were diagnosed by means of a structured interview (SCID-I) based on the DSM-IV criteria, and severity of depression was evaluated by the Beck Depression Inventory. For the neuropsychological assessment, we used standardized scales that measure verbal and visual episodic memory, working memory, executive functions, abstract reasoning and visual-spatial and language abilities. MD patients performed worse than PD patients without depression on two long-term verbal episodic memory tasks, on an abstract reasoning task and on three measures of executive functioning. The MiD patients' performances on the same tests fell between those of the other two groups of PD patients but did not show significant differences. Our results indicate that MD in PD is associated with a qualitatively specific neuropsychological profile that may be related to an alteration of prefrontal and limbic cortical areas. Moreover, the same data suggest that in these patients MiD and MD may represent a gradual continuum associated with increasing cognitive deficits. [source] Cell type-dependent expression of HCN1 in the main olfactory bulbEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2003Noémi B. Holderith Abstract In many brain regions, hyperpolarization-activated cationic currents (Ih) are involved in the generation of rhythmic activities, but the role of Ih in olfactory oscillations remains unclear. Knowledge of the cellular and subcellular distributions of hyperpolarization-activated and cyclic nucleotide-gated channel (HCN) subunits is necessary for understanding the role of Ih in olfactory network activities. Using light microscopic immunocytochemistry, we demonstrate strong HCN1 labelling of the glomerular layer and moderate staining of granule cell, internal and external plexiform layers of the rat main olfactory bulb. In the glomerular layer, among many unlabelled neurons, two distinct subpopulations of juxtaglomerular cells are labelled. Approximately 10% of the juxtaglomerular cells strongly express HCN1. These small diameter cells are immunoreactive for GABA and comprise a subpopulation of periglomerular cells. An additional subset of juxtaglomerular cells (, 1%) expresses low levels of HCN1. They are large in diameter, GABA immunonegative but immunopositive for vesicular glutamate transporter 2, characterizing them as external tufted cells. Quantitative immunogold localization revealed that the somatic plasma membranes of periglomerular cells contain approximately four times more HCN1 labelling than those of external tufted cells. Unlike in cortical pyramidal cells, immunogold density for HCN1 does not significantly differ in somatic and dendritic plasma membranes of external tufted cells, indicating that post-synaptic potentials arriving at proximal and distal dendrites are modulated by the same density of Ih. Our results demonstrate a cell type-dependent expression of HCN1 in the olfactory bulb and predict a differential contribution of distinct juxtaglomerular cell types to network oscillations. [source] Multigenerational analysis of spatial structure in the terrestrial, food-deceptive orchid Orchis masculaJOURNAL OF ECOLOGY, Issue 2 2009Hans Jacquemyn Summary 1In long-lived, terrestrial orchids, strong aggregation of adults and recruits within populations and pronounced spatial association between recruits and adults can be expected when seed dispersal is limited, probabilities of seed germination decrease with increasing distance from mother plants and/or not all mother plants contribute to future generations. When individuals are distributed evenly across life-history stages, these processes can also be expected to result in a significant fine-scale spatial genetic structure in recruits that will persist into the adult-stage class. 2We combined detailed spatial genetic and point pattern analyses across different generations with parentage analyses to elucidate the role of the diverse processes that might determine spatial structure in Orchis mascula. 3Analyses of spatial point patterns showed a significant association between adults and recruits and similar clustering patterns for both. Weak, but highly significant spatial genetic structure was observed in adults and recruits, but no significant differences were observed across life stages, indicating that the spatial genetic structure present in recruits persists into the adult stage. 4Parentage analyses highlighted relatively short seed dispersal distances (median offspring-recruitment distance: 1.55 and 1.70 m) and differential contribution of mother plants to future generations. 5Persistence of fine-scale spatial genetic structure from seedlings into the adult stage class is consistent with the life history of O. mascula, whereas relatively large dispersal distances of both pollen and seeds compared to the fine-scale clustering of adults and seedlings suggest overlapping seed shadows and mixing of genotypes within populations as the major factors explaining the observed weak spatial genetic structure. 6Nonetheless, comparison of the spatial association between recruits and adults with the genetic analysis of offspring-parent distances suggests that the tight clustering of recruits around adults was probably caused by decreasing probabilities of seed germination with increasing distance from mother plants. 7Synthesis. This study shows that the approach presented here, which combines spatial genetic and spatial pattern analyses with parentage analyses, may be broadly applied to other plant species to elucidate the processes that determine spatial structure within their populations. [source] Mitochondrial DNA HVRI variation in Balearic populationsAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2005A. Picornell Abstract The Balearic archipelago (Majorca, Minorca, and Ibiza islands and the Chuetas, a small and inbred community of descendants of Sephardic Jews) and Valencia were studied by means of the sequencing of a 404-bp segment of hypervariable region I (HVRI) mtDNA in 231 individuals. In total, 127 different haplotypes defined by 92 variable positions were identified. The incidence of unique haplotypes was very low, especially in Ibiza and the Chuetas. A remarkable observation in the Chueta community was the high frequency (23%) of preHV-1, a Middle Eastern lineage that is closely related, though not identical, to many others found at high frequencies in different Jewish populations. The presence of this haplogroup convincingly supported the Jewish origin of the Chueta community. The studied populations showed a reduced African contribution, and no individuals were detected with North African haplogroup U6, indicating a lack of maternal contribution from the Moslem settlement to these populations. Only Ibiza showed a lower diversity, indicating a possible genetic drift effect, also supported by the historical information known about this island. The variability in the sequence of mtDNA hypervariable region I correlated well with the existing information from the populations, with the exception of that of the Y-chromosome, which could indicate a differential contribution of the maternal and paternal lineages to the genetic pool of the Balearic Islands. The phylogenetic trees showed the intermediate position of the Chueta population between the Middle Eastern and Majorcan samples, confirming the Jewish origin of this population and their Spanish admixture. Am J Phys Anthropol 128:119-130, 2005. © 2005 Wiley-Liss, Inc. [source] Intracellular calcium regulation among subpopulations of rat dorsal root ganglion neuronsTHE JOURNAL OF PHYSIOLOGY, Issue 1 2006Shao-Gang Lu Primary afferent neurons are functionally heterogeneous. To determine whether this functional heterogeneity reflects, in part, heterogeneity in the regulation of the concentration of intracellular Ca2+ ([Ca2+]i), the magnitude and decay of evoked Ca2+ transients were assessed in subpopulations of dorsal root ganglion (DRG) neurons with voltage clamp and fura-2 ratiometric imaging. To determine whether differences in evoked Ca2+ transients among subpopulations of DRG neurons reflected differences in the contribution of Ca2+ regulatory mechanisms, pharmacological techniques were employed to assess the contribution of influx, efflux, release and uptake pathways. Subpopulations of DRG neurons were defined by cell body size, binding of the plant lectin IB4 and responsiveness to the algogenic compound capsaicin (CAP). Ca2+ transients were evoked with 30 mm K+ or voltage steps to 0 mV. There were marked differences between subpopulations of neurons with respect to both the magnitude and decay of the Ca2+ transient, with the largest and most slowly decaying Ca2+ transients in small-diameter, IB4 -positive, CAP-responsive neurons. The smallest and most rapidly decaying transients were in large-diameter, IB4 -negative and CAP-unresponsive DRG neurons. These differences were not due to a differential distribution of voltage-gated Ca2+ currents. However, these differences did appear to reflect a differential contribution of other influx, efflux, release and uptake mechanisms between subpopulations of neurons. These results suggest that electrical activity in subpopulations of DRG neurons will have a differential influence on Ca2+ -regulated phenomena such as spike adaptation, transmitter release and gene transcription. Significantly more activity should be required in large-diameter non-nociceptive afferents than in small-diameter nociceptive afferents to have a comparable influence on these processes. [source] Interneuron subtype specific activation of mGluR1/5 during epileptiform activity in hippocampusEPILEPSIA, Issue 8 2010Nathalie T Sanon Summary Purpose:, Specific inhibitory interneurons in area CA1 of the hippocampus, notably those located in stratum oriens,alveus (O/A-INs), are selectively vulnerable in patients and animal models of temporal lobe epilepsy (TLE). The excitotoxic mechanisms underlying the selective vulnerability of interneurons have not been identified but could involve group I metabotropic glutamate receptor subtypes (mGluR1/5), which have generally proconvulsive actions and activate prominent cationic currents and calcium responses specifically in O/A-INs. Methods:, In this study, we examine the role of mGluR1/5 in interneurons during epileptiform activity using whole-cell recordings from CA1 O/A-INs and selective antagonists of mGluR1, (LY367385) and mGluR5 (MPEP) in a disinhibited rat hippocampal slice model of epileptiform activity. Results:, Our data indicate more prominent epileptiform burst discharges and paroxysmal depolarizations (PDs) in O/A-INs than in interneurons located at the border of strata radiatum and lacunosum/moleculare (R/LM-INs). In addition, mGluR1 and mGluR5 significantly contributed to epileptiform responses in O/A-INs but not in R/LM-INs. Epileptiform burst discharges in O/A-INs were partly dependent on mGluR5. PDs and associated postsynaptic currents were dependent on both mGluR1, and mGluR5. These receptors contributed differently to postsynaptic currents underlying PDs, with mGluR5 contributing to the fast and slow components and mGluR1, to the slow component. Discussion:, These findings support interneuron subtype-specific activation and differential contributions of mGluR1, and mGluR5 to epileptiform activity in O/A-INs, which could be important for their selective vulnerability in TLE. [source] Heritability of hippocampal size in elderly twin men: Equivalent influence from genes and environmentHIPPOCAMPUS, Issue 6 2001Edith V. Sullivan Abstract Recent studies have established that environmental factors can modify hippocampal structure and enhance function in adult rodents, but the extent to which genes and the environment exert differential contributions to hippocampal structural integrity in humans is unknown. Here, we applied the twin model in a large sample of elderly twin men to examine in late life the balance of environmental and genetic effects on the size of the hippocampus in comparison with other brain structures. This study provides novel evidence that the volume of the hippocampus, as measured on MRI, is subject to substantially less genetic control than are comparison brain regions also measured: temporal horn volume, midsagittal area of the corpus callosum, and intracranial volume (ICV). In particular, about 60% of the temporal horn variance and 80% of the callosal and ICV variance was attributable to genetic influences, whereas only 40% of the hippocampal variance was attributable to genetic influences. These results suggest that environment, whether by itself or in interaction with genes, has the potential of exerting greater and possibly longer control in modifying hippocampal size than other brain regions that are under greater genetic control. Considering the potential of environmental modification of this structure suggested by lower heritability, the hippocampus appears well-suited to support the dynamic processes of encoding and consolidation of new, declarataive memories. Hippocampus 2001;11:754,762. © 2001 Wiley-Liss, Inc. [source] Functional connectivity of default mode network components: Correlation, anticorrelation, and causalityHUMAN BRAIN MAPPING, Issue 2 2009Lucina Q. Uddin Abstract The default mode network (DMN), based in ventromedial prefrontal cortex (vmPFC) and posterior cingulate cortex (PCC), exhibits higher metabolic activity at rest than during performance of externally oriented cognitive tasks. Recent studies have suggested that competitive relationships between the DMN and various task-positive networks involved in task performance are intrinsically represented in the brain in the form of strong negative correlations (anticorrelations) between spontaneous fluctuations in these networks. Most neuroimaging studies characterize the DMN as a homogenous network, thus few have examined the differential contributions of DMN components to such competitive relationships. Here, we examined functional differentiation within the DMN, with an emphasis on understanding competitive relationships between this and other networks. We used a seed correlation approach on resting-state data to assess differences in functional connectivity between these two regions and their anticorrelated networks. While the positively correlated networks for the vmPFC and PCC seeds largely overlapped, the anticorrelated networks for each showed striking differences. Activity in vmPFC negatively predicted activity in parietal visual spatial and temporal attention networks, whereas activity in PCC negatively predicted activity in prefrontal-based motor control circuits. Granger causality analyses suggest that vmPFC and PCC exert greater influence on their anticorrelated networks than the other way around, suggesting that these two default mode nodes may directly modulate activity in task-positive networks. Thus, the two major nodes comprising the DMN are differentiated with respect to the specific brain systems with which they interact, suggesting greater heterogeneity within this network than is commonly appreciated. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source] Race and sex differences and contribution of height: A study on bone size in healthy Caucasians and ChineseAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2005Yuan-Yuan Zhang Osteoporosis is characterized by a loss of bone strength, of which bone size (BS) is an important determinant. However, studies on the factors determining BS are relatively few. The present study evaluated the independent effects of height, age, weight, sex, and race on areal BS at the hip and spine, measured by dual-energy X-ray absorptiometry, while focusing on the differential contributions of height to BS across sex, race, and skeletal site. The subjects were aged 40 years or older, including 763 Chinese (384 males and 379 females) from Shanghai, People's Republic of China, and 424 Caucasians (188 males and 236 females) from Omaha, Nebraska. Basically, Caucasians had significantly larger BS than Chinese. After adjusting for height, age, and weight, the Chinese had similar spine BS, but significantly larger intertrochanter BS in both sexes and larger total hip BS in females compared with Caucasians. Males had significantly larger BS than females before and after adjustment in both ethnic groups. The effects of age, weight, and race varied, depending on skeletal site. As expected, height had major effects on BS variation in both sexes and races. Height tended to account for larger BS variation at the spine than at the hip (except for Chinese females), and larger BS variation in Caucasians than in Chinese of the same sex (except for the trochanter in females). We conclude that height is a major predictor for BS, and its contributions vary across sex, race, and skeletal site. Am. J. Hum. Biol. 17:568,575, 2005. © 2005 Wiley-Liss, Inc. [source] | |||||||||||||