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Different Subpopulations (different + subpopulation)
Selected AbstractsRelationship of glucose regulation to changes in weight: a systematic review and guide to future researchDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 5 2010Ching-Ju Chiu Abstract Although weight gain and obesity are risk factors for poor glucose regulation, the relationship, if any, of glucose regulation to changes in weight is not well understood. The purpose of this study was to conduct a systematic review of research examining the relationship of glucose regulation to changes in weight in human-based studies and to provide guidelines for future research in this area. We searched electronic databases and reference sections of relevant articles, including both diabetic and non-diabetic populations, to locate all the literature published before February 2010, and then conducted a systematic review across studies to compare the research designs and findings. The 22 studies meeting our criteria for review generally supported the relationship of glucose regulation to changes in weight. Three studies reported that poor glucose regulation is associated with weight gain; 12 studies concluded that poor glucose regulation is associated with weight loss; 5 showed complex relationships depending on age, sex, or race/ethnicity; and 2 suggested no relationship. The diverse findings may imply that the direction (negative or positive) of the relationship may depend on specific conditions. More research focused on different subpopulations may provide more definitive information supplemental to the current preliminary findings. Recommendations regarding future research in this particular area are provided in the discussion. Copyright © 2010 John Wiley & Sons, Ltd. [source] C1 neurons in the rat rostral ventrolateral medulla differentially express vesicular monoamine transporter 2 in soma and axonal compartmentsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2008C. P. Sevigny Abstract Vesicular monoamine transporter 2 (VMAT2) packages biogenic amines into large dense core and synaptic vesicles for either somatodendritic or synaptic release from neurons of the CNS. Whilst the distribution of VMAT2 has been well characterized in many catecholaminergic cell groups, its localization amongst C1 adrenergic neurons in the medulla has not been examined in detail. Within the rostral ventrolateral medulla (RVLM), C1 neurons are a group of barosensitive, adrenergic neurons. Rostral C1 cells project to the thoracic spinal cord and are considered sympathetic premotor neurons. The majority of caudal C1 cells project rostrally to regions such as the hypothalamus. The present study sought to quantitate the somatodendritic expression of VMAT2 in C1 neurons, and to assess the subcellular distribution of the transporter. Immunoreactivity for VMAT2 occurred in 31% of C1 soma, with a high proportion of these in the caudal part of the RVLM. Retrograde tracing studies revealed that only two of 43 bulbospinal C1 neurons contained faint VMAT2-immunoreactivity, whilst 88 ± 5% of rostrally projecting neurons were VMAT2-positive. A lentivirus, designed to express green fluorescent protein exclusively in noradrenergic and adrenergic neurons, was injected into the RVLM to label C1 neurons. Eighty-three percent of C1 efferents that occurred in close proximity to sympathetic preganglionic neurons within the T3 intermediolateral cell column contained VMAT2-immunoreactivity. These data demonstrate differential distribution of VMAT2 within different subpopulations of C1 neurons and suggest that this might reflect differences in somatodendritic vs. synaptic release of catecholamines. [source] Prokineticin 2 depolarizes paraventricular nucleus magnocellular and parvocellular neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2007Erik A. Yuill Abstract Blind whole-cell patch-clamp techniques were used to examine the effects of prokineticin 2 (PK2) on the excitability of magnocellular (MNC), parvocellular preautonomic (PA), and parvocellular neuroendocrine (NE) neurons within the hypothalamic paraventricular nucleus (PVN) of the rat. The majority of MNC neurons (76%) depolarized in response to 10 nm PK2, effects that were eliminated in the presence of tetrodotoxin (TTX). PK2 also caused an increase in excitatory postsynaptic potential (EPSP) frequency, a finding that was confirmed by voltage clamp recordings demonstrating increases in excitatory postsynaptic current (EPSC) frequency. The depolarizing effects of PK2 on MNC neurons were also abolished by kynurenic acid (KA), supporting the conclusion that the effects of PK2 are mediated by the activation of glutamate interneurons within the hypothalamic slice. PA (68%) and NE (67%) parvocellular neurons also depolarized in response to 10 nm PK2. However, in contrast to MNC neurons, these effects were maintained in TTX, indicating that PK2 directly affects PA and NE neurons. PK2-induced depolarizations observed in PA and NE neurons were found to be concentration-related and receptor mediated, as experiments performed in the presence of A1MPK1 (a PK2 receptor antagonist) abolished the effects of PK2 on these subpopulations of neurons. The depolarizing effects of PK2 on PA and NE neurons were also shown to be abolished by PD 98059 (a mitogen activated protein kinase (MAPK) inhibitor) suggesting that PK2 depolarizes PVN parvocellular neurons through a MAPK signalling mechanism. In combination, these studies have identified separate cellular mechanisms through which PK2 influences the excitability of different subpopulations of PVN neurons. [source] Determinants of influenza vaccination timingHEALTH ECONOMICS, Issue 8 2005Byung Kwang Yoo Abstract New guidelines recommend different influenza vaccination timing for different subpopulations due to the limited availability of flu shots (FS). This study's objectives are to develop a theoretical model to demonstrate why some individuals choose to receive an early FS while others choose a late FS and to empirically explore the determinants of vaccination timing. Empirical results generally supported the theoretical results. Individuals vary their FS timing in response to variations in perceived risks, chronic condition levels reflecting their risk of influenza infection, and opportunity costs, measured by the presence of medical care other than an FS. Copyright © 2005 John Wiley & Sons, Ltd. [source] Nesfatin-1 Influences the Excitability of Paraventricular Nucleus NeuronesJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2008C. J. Price Nesfatin-1 is a newly-discovered satiety peptide found in several nuclei of the hypothalamus, including the paraventricular nucleus. To begin to understand the physiological mechanisms underlying these satiety-inducing actions, we examined the effects of nesfatin-1 on the excitability of neurones in the paraventricular nucleus. Whole-cell current-clamp recordings from rat paraventricular nucleus neurones showed nesfatin-1 to have either hyperpolarising or depolarising effects on the majority of neurones tested. Both types of response were observed in neurones irrespective of classification based on electrophysiological fingerprint (magnocellular, neuroendocrine or pre-autonomic) or molecular phenotype (vasopressin, oxytocin, corticotrophin-releasing hormone, thyrotrophin-releasing hormone or vesicular glutamate transporter), determined using single cell reverse transcription-poylmerase chain reaction. Consequently, we provide the first evidence that this peptide, which is produced in the paraventricular nucleus, has effects on the membrane potential of a large proportion of different subpopulations of neurones located in this nucleus, and therefore identify nesfatin-1 as a potentially important regulator of paraventricular nucleus output. [source] Age-Related Gray Matter Shrinkage in a Treatment Naïve Actively Drinking Alcohol-Dependent SampleALCOHOLISM, Issue 1 2010George Fein Background:, We previously demonstrated, in a small sample, steeper age-related gray matter shrinkage in treatment naïve alcohol-dependent (TxN) men compared to nonalcoholic controls, but could not separate out the contributions of age and lifetime duration of alcohol use (which were highly correlated) to this effect. In the current study, we have quadrupled the sample size and expanded it to include both men and women to try to replicate and extend the previous findings and to separate the contributions of age and alcohol use to the phenomenon. Methods:, In the current study, we examine cortical gray matter volumes in 18- to 50-year-old TxN (n = 84) versus age and gender comparable controls (n = 67). We used a new Region of Interest Analysis method which accounts for differences in sulcal and gyral enfolding between individuals (Fein et al., 2009a). Results:, We found greater age-related gray matter shrinkage in TxN than in controls. Partial correlation analysis showed that the effect was a function of age and not lifetime alcohol burden. Conclusions:, Implications of the findings are discussed in terms of their contribution toward our knowledge of differences between different subpopulations of alcoholics and in terms of their implications for the morbidity of alcohol dependence in an aging national population. [source] Impaired Terminal Differentiation of Pulmonary Macrophages in a Guinea Pig Model of Chronic Ethanol IngestionALCOHOLISM, Issue 10 2009Sheena D. Brown Background:, Alcoholic patients have an increased risk of respiratory infections, which is partially due to an impaired immune response of alveolar macrophages. The mechanisms by which alcohol impairs alveolar macrophage function are poorly understood. In this study, we demonstrated in a guinea pig model that chronic ethanol ingestion significantly impaired alveolar macrophage differentiation and function. Methods:, Isolated alveolar macrophages were separated into 4 different subpopulations with varying densities and levels of maturation. Results: Compared to control values, chronic ethanol ingestion decreased the percentage of alveolar macrophages in the mature fractions by ,60%. Alveolar macrophage function in each subpopulation was determined by measuring phagocytosis of fluorescein isothiocyanate-labeled Staphylococcus aureus. Alveolar macrophages from ethanol-fed animals had ,80% decrease in the phagocytic index. Western blot and immunohistochemical analysis of the differential markers granulocyte/macrophage colony-stimulating factor (GM-CSF) receptor , (GM-CSFR-,), PU.1, CD11c, and CD11b verified that alcoholic macrophages displayed impaired terminal differentiation. While oral supplementation with the glutathione precursor S -adenosyl-methionine (SAM) did not alter the maturational status of control animals, SAM supplementation shifted the distribution of macrophages to more mature fractions, normalized the phagocytic index; as well as normalized expression of CD11c, CD11b, PU.1, and GM-CSFR-,. Chronic ethanol ingestion also impaired the differentiation status of interstitial macrophages which was normalized by SAM supplementation. Conclusion:, This improvement in the maturational status suggested that ethanol-induced oxidant stress is a central feature in impaired terminal differentiation of macrophages in the interstitial and alveolar space. Therefore, strategies targeting pulmonary oxidant stress may restore macrophage differentiation and function even after chronic ethanol ingestion. [source] Variation in pollen dispersal between years with different pollination conditions in a tropical emergent treeMOLECULAR ECOLOGY, Issue 11 2004T. KENTA Abstract We examined differences in pollen dispersal efficiency between 2 years in terms of both spatial dispersal range and genetic relatedness of pollen in a tropical emergent tree, Dipterocarpus tempehes. The species was pollinated by the giant honeybee (Apis dorsata) in a year of intensive community-level mass-flowering or general flowering (1996), but by several species of moths in a year of less-intensive general flowering (1998). We carried out paternity analysis based on six DNA microsatellite markers on a total of 277 mature trees forming four spatially distinct subpopulations in a 70 ha area, and 147 and 188 2-year-old seedlings originating from seeds produced in 1996 and 1998 (cohorts 96 and 98, respectively). Outcrossing rates (0.93 and 0.96 for cohorts 96 and 98, respectively) did not differ between years. Mean dispersal distances (222 and 192 m) were not significantly different between the 2 years but marginally more biased to long distance in 1996. The mean relatedness among cross-pollinated seedlings sharing the same mothers in cohort 96 was lower than that in cohort 98. This can be attributed to the two facts that the proportion of intersubpopulations pollen flow among cross-pollination events was marginally higher in cohort 96 (44%) than in cohort 98 (33%), and that mature trees within the same subpopulations are genetically more related to each other than those between different subpopulations. We conclude that D. tempehes maintained effective pollen dispersal in terms of outcrossing rate and pollen dispersal distance in spite of the large difference in foraging characteristics between two types of pollinators. In terms of pollen relatedness, however, a slight difference was suggested between years in the level of biparental inbreeding. [source] Impact of BCR/ABL gene expression on the proliferative rate of different subpopulations of haematopoietic cells in chronic myeloid leukaemiaBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2006Daniel Primo Summary Despite the effects of BCR ABL on cell proliferation, no study has compared the proliferative rate of different haematopoietic cell compartments from chronic myeloid leukaemia (CML) with those of normal bone marrow (NBM). We comparatively analysed the cell cycle distribution and BCR/ABL expression in different compartments of BM cells from 15 CML and 11 NBM. Overall, our results showed similar proliferative indices in CML patients and NBM. However, CD34+ myeloid precursors from CML patients displayed an increased proportion of S + G2/M-phase cells (P = 0·04), while no significant differences were found between CML and NBM for other BM cell subsets analysed. In BM cells separated by fluorescence-activated cell sorting, decreasing levels of BCR/ABL mRNA were found from CD34+/CD38+ myeloid precursors to myeloblasts; BCR/ABL expression increased afterwards with a peak at the myelocyte/metamyelocyte stage, decreasing in the more mature band/neutrophil compartment. Unexpectedly, BCR/ABL gene expression showed an inverse correlation with the proportion of S + G2/M-phase cells (R = ,0·33; P = 0·04). These results suggest that in CML, BCR/ABL expression is associated with an increased proliferation of CD34+ myeloid haematopoietic progenitor cells but not of other more mature myeloid precursors, as confirmed by the observation of an inverse correlation between the amount of BCR/ABL transcripts and the proportion of S + G2/M-phase cells. [source] | |||||||||||||