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Selected AbstractsLatin America and the Social Contract: Patterns of Social Spending and TaxationPOPULATION AND DEVELOPMENT REVIEW, Issue 4 2009Karla Breceda This article analyzes the incidence of social spending and taxation by income quintile for seven Latin American countries, the United Kingdom, and the United States. Absolute levels of social spending in Latin America are fairly flat across income quintiles, a pattern similar to that in the United States and differing from the more progressive pattern of spending in the United Kingdom. The structure of taxation in Latin America is also similar to that of the United States. Because of high income inequality in Latin America and the US, the rich bear of most the burden, whereas the United Kingdom taxes the middle class to a greater extent. The analysis suggests that many Latin American countries are trapped in a vicious cycle in which the rich resist the expansion of the welfare state (because they bear most of its tax burden without receiving commensurate benefits), and their opposition to its expansion in turn maintains long-term inequalities. [source] Dual Economies and International Total Factor Productivity Differences: Channelling the Impact from Institutions, Trade, and GeographyECONOMICA, Issue 300 2008AREENDAM CHANDA This paper provides a framework that decomposes aggregate total factor productivity (TFP) into a component reflecting relative efficiency across sectors, and another component that reflects the absolute level of efficiency. A development accounting analysis suggests that as much as 85% of the international variation in aggregate TFP can be attributed to variation in relative efficiency across sectors. Estimation results show that recent findings highlighting the importance of strong protection of property rights, financial development and geographical advantage for the level of TFP, can be explained by their impact on relative efficiency. [source] Do mtDNA deletions drive premature aging in mtDNA mutator mice?AGING CELL, Issue 4 2009Yevgenya Kraytsberg Summary Deletions in mitochondrial DNA (mtDNA) have long been suspected to be involved in mammalian aging, but their role remains controversial. Recent research has demonstrated that relatively higher levels of mtDNA deletions correlate with premature aging in mtDNA mutator mice, which led to the conclusion that premature aging in these mice is driven by mtDNA deletions. However, it is reported here that the absolute level of deletions in mutator mice is quite low, especially when compared with the level of point mutations in these mice. It is thus argued that the available data are insufficient to conclude that mtDNA mutations drive premature aging in mtDNA mutator mice. It remains possible that clonal expansion of mtDNA deletions may result in sufficiently high levels to play a role in age-related dysfunction in some cells, but assessing this possibility will require studies of the distribution of these deletions among different cell types and in individual cells. [source] Preoperative evaluation and triage of women with suspicious adnexal masses using risk of malignancy indexJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 1 2009Christopher A. Enakpene Abstract Aims:, To test the accuracy of risk of malignancy index (RMI) in preoperative prediction of malignancy and treatment of adnexal masses. Methods:, A total of 302 women with ultrasound diagnosed adnexal masses, and serum measurement of cancer-associated antigen CA-125 levels, were studied. They all had surgical exploration between October 2001 and September 2005 at the Friedrich-Alexander University Women's Hospital, Erlangen, Germany. The RMI was based on menopausal status, ultrasound morphology of adnexal masses and absolute level of serum CA-125. A cut-off of 250 was chosen as the threshold for determining the type of surgical operations (laparotomy versus laparoscopy) and the skill of the surgeons (gynecological oncologist versus general gynecologist). The data obtained were analyzed for baseline characteristics using ,2 test and analysis of variance (ANOVA). P < 0.05 were statistically significant. The various testing methods were evaluated for sensitivity, specificity, positive and negative predictive values. Results:, The best individual performance was found in RMI at a cut-off of 250 with a sensitivity of 88.2%, specificity of 74.3%, positive predictive value of 71.3% and negative predictive value of 90%. When RMI was used to triage patient treatment, 81.5% of patients who had laparoscopy had histological diagnosis of benign ovarian tumor and 7.5% had malignant tumor. In contrast, 74.4% of patients who had laparotomy had histological diagnosis of malignant ovarian tumor and 16% had benign tumor. Conclusion:, Risk of malignant index is a reliable, cheap, readily available and cost-effective method of preoperative discrimination of benign from malignant adnexal masses. It is also helpful in triaging patients to different treatment groups. [source] The foaming of mixtures of albumin and hordein protein hydrolysates in model systemsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2004CW Bamforth Abstract Although hydrolysed albumin and hydrolysed hordein derived from barley are independently capable of stabilising foams in model beer solutions, when both are present together, the net foam stability is less than anticipated. In particular, it seems that hordein, even in an unhydrolysed state, interferes with the ability of albumin-derived polypeptides to stabilise foam. It appears, therefore, that the observed foam stability of a product such as beer is not only dependent on the absolute level of individual foam-stabilising polypeptides but also on the relative proportions of polypeptides derived from the albumin and hordein protein subsets. Copyright © 2004 Society of Chemical Industry [source] Lawyers' Roles in Voluntary Associations: Declining Social Capital?LAW & SOCIAL INQUIRY, Issue 3 2001John P. Heinz The extent and nature of lawyers'participation in civic life probably has important effects on the character of the community's activity and its out-comes. Where and how lawyers participate in voluntary associations may influence the ability of those organizations to function within the larger structure of American institutions. This paper compares findings from two surveys of Chicago lawyers, the first conducted in 1975 and the second in 1994-95. Contrary to some expectations, the available evidence does not suggest that community activities of lawyers decreased. Moreover, lawyers'energies in 1995 appear to have been devoted more often to socially concerned organizations, those with a reformist agenda, than had been the case in 1975. The types of organizations with the greatest increase in activity were religious and civic associations. A smaller percentage of the respondents held leadership positions in 1995 than in 1975, but, because of a doubling in the number of lawyers, the best estimate is that the bar's absolute level of contribution to community leadership did not change greatly. In both 1975 and 1995, a hierarchy of social prestige appears to have influenced the pattern of lawyers'community activities. Lawyers who had higher incomes, were middle-aged, were Protestants, and who had attended elite law schools were more likely to be active or leaders in most kinds of organizations. In ethnic and fraternal organizations, however, the elites of the profession had relatively low rates of participation, while government lawyers, solo practitioners, and graduates of less prestigious law schools predominated. Status hierarchies within the broader community,as well as social differences in taste, preference, or "culture",clearly penetrate the bar. [source] Comparative analysis of neonicotinoid binding to insect membranes: II.PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2004An unusual high affinity site for [3H]thiamethoxam in Myzus persicae, Aphis craccivora Abstract Neonicotinoids represent a class of insect-selective ligands of nicotinic acetylcholine receptors. Imidacloprid, the first commercially used neonicotinoid insecticide, has been studied on neuronal preparations from many insects to date. Here we report first intrinsic binding data of thiamethoxam, using membranes from Myzus persicae Sulzer and Aphis craccivora Koch. In both aphids, specific binding of [3H]thiamethoxam was sensitive to temperature, while the absolute level of non-specific binding was not affected. In M persicae, binding capacity (Bmax) for [3H]thiamethoxam was ca 450 fmol mg,1 of protein at 22 °C and ca 700 fmol mg,1 of protein at 2 °C. The negative effect of increased temperature was reversible and hence not due to some destructive process. The affinity for [3H]thiamethoxam was less affected by temperature: Kd was ca 11 nM at 2 °C and ca 15 nM at 22 °C. The membranes also lost binding sites for [3H]thiamethoxam during prolonged storage at room temperature, and upon freezing and thawing. In A craccivora, [3H]thiamethoxam was bound with a capacity of ca 1000 fmol mg,1 protein and an affinity of ca 90 nM, as measured at 2 °C. Overall, the in vitro temperature sensitivity of [3H]thiamethoxam binding was in obvious contrast to the behaviour of [3H]imidacloprid studied in parallel. Moreover, the binding of [3H]thiamethoxam was inhibited by imidacloprid in a non-competitive mode, as shown with M persicae. In our view, these differences demonstrate that thiamethoxam and imidacloprid, which represent different structural sub-classes of neonicotinoids, do not share the same binding site or mode. This holds also for other neonicotinoids, as we report in a companion article. Copyright © 2004 Society of Chemical Industry [source] Elevated carbon dioxide increases nitrate uptake and nitrate reductase activity when tobacco is growing on nitrate, but increases ammonium uptake and inhibits nitrate reductase activity when tobacco is growing on ammonium nitratePLANT CELL & ENVIRONMENT, Issue 11 2001P. Matt Abstract The influence of elevated [CO2] on the uptake and assimilation of nitrate and ammonium was investigated by growing tobacco plants in hydroponic culture with 2 mm nitrate or 1 mm ammonium nitrate and ambient or 800 p.p.m. [CO2]. Leaves and roots were harvested at several times during the diurnal cycle to investigate the levels of the transcripts for a high-affinity nitrate transporter (NRT2), nitrate reductase (NIA), cytosolic and plastidic glutamine synthetase (GLN1, GLN2), the activity of NIA and glutamine synthetase, the rate of 15N-nitrate and 15N-ammonium uptake, and the levels of nitrate, ammonium, amino acids, 2-oxoglutarate and carbohydrates. (i) In source leaves of plants growing on 2 mm nitrate in ambient [CO2], NIA transcript is high at the end of the night and NIA activity increases three-fold after illumination. The rate of nitrate reduction during the first part of the light period is two-fold higher than the rate of nitrate uptake and exceeds the rate of ammonium metabolism in the glutamate: oxoglutarate aminotransferase (GOGAT) pathway, resulting in a rapid decrease of nitrate and the accumulation of ammonium, glutamine and the photorespiratory intermediates glycine and serine. This imbalance is reversed later in the diurnal cycle. The level of the NIA transcript falls dramatically after illumination, and NIA activity and the rate of nitrate reduction decline during the second part of the light period and are low at night. NRT2 transcript increases during the day and remains high for the first part of the night and nitrate uptake remains high in the second part of the light period and decreases by only 30% at night. The nitrate absorbed at night is used to replenish the leaf nitrate pool. GLN2 transcript and glutamine synthetase activity rise to a maximum at the end of the day and decline only gradually after darkening, and ammonium and amino acids decrease during the night. (ii) In plants growing on ammonium nitrate, about 30% of the nitrogen is derived from ammonium. More ammonium accumulates in leaves during the day, and glutamine synthetase activity and glutamine levels remain high through the night. There is a corresponding 30% inhibition of nitrate uptake, a decrease of the absolute nitrate level, and a 15,30% decrease of NIA activity in the leaves and roots. The diurnal changes of leaf nitrate and the absolute level and diurnal changes of the NIA transcript are, however, similar to those in nitrate-grown plants. (iii) Plants growing on nitrate adjust to elevated [CO2] by a coordinate change in the diurnal regulation of NRT2 and NIA, which allows maximum rates of nitrate uptake and maximum NIA activity to be maintained for a larger part of the 24 h diurnal cycle. In contrast, tobacco growing on ammonium nitrate adjusts by selectively increasing the rate of ammonium uptake, and decreasing the expression of NRT2 and NIA and the rate of nitrate assimilation. In both conditions, the overall rate of inorganic nitrogen utilization is increased in elevated [CO2] due to higher rates of uptake and assimilation at the end of the day and during the night, and amino acids are maintained at levels that are comparable to or even higher than in ambient [CO2]. (iv) Comparison of the diurnal changes of transcripts, enzyme activities and metabolite pools across the four growth conditions reveals that these complex diurnal changes are due to transcriptional and post-transcriptional mechanisms, which act several steps and are triggered by various signals depending on the condition and organ. The results indicate that nitrate and ammonium uptake and root NIA activity may be regulated by the sugar supply, that ammonium uptake and assimilation inhibit nitrate uptake and root NIA activity, that the balance between the influx and utilization of nitrate plays a key role in the diurnal changes of the NIA transcript in leaves, that changes of glutamine do not play a key role in transcriptional regulation of NIA in leaves but instead inhibit NIA activity via uncharacterized post-transcriptional or post-translational mechanisms, and that high ammonium acts via uncharacterized post-transcriptional or post-translational mechanisms to stabilize glutamine synthetase activity during the night. [source] GDNF and insulin cooperate to enhance the proliferation and differentiation of enteric crest-derived cellsDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2003Paul J. Focke Abstract Previously we have shown that glial derived neurotrophic factor (GDNF) stimulates modest increases in the proliferation of avian enteric crest-derived cells and similar increases in the phosphorylation of the phosphoinositide 3,kinase (PI3K) downstream substrate Akt (Akt-P). In the present study we tested whether GDNF-independent increases in PI3K activation would be sufficient to support proliferation. We found that insulin induces a large increase in the phosphorylation of Akt and can initiate DNA synthesis in avian enteric crest-derived cells, but is unable to maintain proliferation over time in culture, measured by BrdU incorporation. GDNF can also initiate DNA synthesis, but it too is unable to maintain BrdU incorporation in cultured enteric crest-derived cells. Sustained incorporation of BrdU after 16,48 h in culture is shown to be dependent on a combination of GDNF and insulin. Using a phospho-specific antibody, we found Akt-P levels to be similar in the proliferating (BrdU incorporation maintained from 16,48 h in culture) and nonproliferating populations, suggesting that Akt-P levels were not solely controlling the extent of BrdU incorporation. A minimum level of PI3K activation, however, is required, as shown by the dose-dependent reduction in proliferation with the PI3K inhibitor LY-294002. We conclude that the integrity of the PI3K pathway is essential for enteric crest-derived cell proliferation, but that the absolute levels of Akt-P do not determine the extent of proliferation. The enhanced proliferation in cultures containing both GDNF and insulin suggests that other pathways are involved, including the possibility that PI3K downstream effectors other than Akt are important in the regulation of avian enteric crest-derived cell proliferation. © 2003 Wiley Periodicals, Inc. J Neurobiol 55: 151,164, 2003 [source] Do You Enjoy Having More than Others?ECONOMICA, Issue 296 2007Survey Evidence of Positional Goods Although conventional economic theory proposes that only the absolute levels of income and consumption matter for people's utility, there is much evidence that relative concerns are often important. This paper uses a choice experiment to measure people's perceptions of the degree to which such concerns matter, i.e. the degree of positionality. Based on a random sample in Sweden, income and cars are found to be highly positional, on average, in contrast to leisure and car safety. Leisure may even be completely non-positional. Potential policy implications are discussed. [source] Mean age-of-onset of familial alzheimer disease caused by presenilin mutations correlates with both increased A,42 and decreased A,40,,§HUMAN MUTATION, Issue 7 2006Samir Kumar-Singh Abstract The varied ways in which mutations in presenilins (PSEN1 and PSEN2) affect amyloid b precursor protein (APP) processing in causing early-onset familial Alzheimer disease (FAD) are complex and not yet properly understood. Nonetheless, one useful diagnostic marker is an increased ratio of Ab42 to Ab40 (Ab42/Ab40) in patients' brain and biological fluids as well as in transgenic mice and cells. We studied Ab and APP processing for a set of nine clinical PSEN mutations on a novel and highly reproducible enzyme-linked immunosorbent assay (ELISA)-based in vitro method and also sought correlation with brain Ab analyzed by image densitometry and mass spectrometry. All mutations significantly increased Ab42/Ab40 in vitro by significantly decreasing Ab40 with accumulation of APP C-terminal fragments, a sign of decreased PSEN activity. A significant increase in absolute levels of Ab42 was observed for only half of the mutations tested. We also showed that age-of-onset of PSEN1-linked FAD correlated inversely with Ab42/Ab40 (r=,0.89; P=0.001) and absolute levels of Ab42 (r=,0.83; P=0.006), but directly with Ab40 levels (r=0.69; P=0.035). These changes also partly correlated with brain Ab42 and Ab40 levels. Together, our data suggested that Ab40 might be protective by perhaps sequestering the more toxic Ab42 and facilitating its clearance. Also, the in vitro method we describe here is a valid tool for assaying the pathogenic potential of clinical PSEN mutations in a molecular diagnostic setting. Hum Mutat 27(7), 686,695, 2006. Published 2006 Wiley-Liss, Inc. [source] Poverty and deprivation among children in Eastern Europe and Central AsiaINTERNATIONAL JOURNAL OF SOCIAL WELFARE, Issue 3 2009Leonardo Menchini Although there is now a large body of literature on poverty in the countries of Eastern Europe and Central Asia, there remains a dearth of comparative analysis of child poverty and wellbeing. This article uses household survey microdata for the period 2001,2003 to compare absolute poverty, relative poverty, material deprivation and participation in schooling among children in five countries: Albania, Bulgaria, Moldova, Russia and Tajikistan. The analysis shows that low absolute levels of household consumption are associated with other deprivation indicators and with children's participation in schooling. The article also highlights the usefulness of relative poverty measures that effectively identify children at risk of exclusion in even the poorest countries in the region. The article concludes by arguing that household consumption is a good indicator of child poverty and deprivation in the region, and that relative poverty measures should be more widely used in monitoring global targets for poverty reduction. [source] Femoral Neck BMD Is a Strong Predictor of Hip Fracture Susceptibility in Elderly Men and Women Because It Detects Cortical Bone Instability: The Rotterdam Study,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2007Fernando Rivadeneira Abstract We studied HSA measurements in relation to hip fracture risk in 4806 individuals (2740 women). Hip fractures (n = 147) occurred at the same absolute levels of bone instability in both sexes. Cortical instability (propensity of thinner cortices in wide diameters to buckle) explains why hip fracture risk at different BMD levels is the same across sexes. Introduction: Despite the sexual dimorphism of bone, hip fracture risk is very similar in men and women at the same absolute BMD. We aimed to elucidate the main structural properties of bone that underlie the measured BMD and that ultimately determines the risk of hip fracture in elderly men and women. Materials and Methods: This study is part of the Rotterdam Study (a large prospective population-based cohort) and included 147 incident hip fracture cases in 4806 participants with DXA-derived hip structural analysis (mean follow-up, 8.6 yr). Indices compared in relation to fracture included neck width, cortical thickness, section modulus (an index of bending strength), and buckling ratio (an index of cortical bone instability). We used a mathematical model to calculate the hip fracture distribution by femoral neck BMD, BMC, bone area, and hip structure analysis (HSA) parameters (cortical thickness, section modulus narrow neck width, and buckling ratio) and compared it with prospective data from the Rotterdam Study. Results: In the prospective data, hip fracture cases in both sexes had lower BMD, thinner cortices, greater bone width, lower strength, and higher instability at baseline. In fractured individuals, men had an average BMD that was 0.09 g/cm2 higher than women (p < 0.00001), whereas no significant difference in buckling ratios was seen. Modeled fracture distribution by BMD and buckling ratio levels were in concordance to the prospective data and showed that hip fractures seem to occur at the same absolute levels of bone instability (buckling ratio) in both men and women. No significant differences were observed between the areas under the ROC curves of BMD (0.8146 in women and 0.8048 in men) and the buckling ratio (0.8161 in women and 0.7759 in men). Conclusions: The buckling ratio (an index of bone instability) portrays in both sexes the critical balance between cortical thickness and bone width. Our findings suggest that extreme thinning of cortices in expanded bones plays a key role on local susceptibility to fracture. Even though the buckling ratio does not offer additional predictive value, these findings improve our understanding of why low BMD is a good predictor of fragility fractures. [source] Diffusely elevated cerebral choline and creatine in relapsing-remitting multiple sclerosisMAGNETIC RESONANCE IN MEDICINE, Issue 1 2003Matilde Inglese Abstract It is well known that multiple sclerosis (MS) pathogenesis continues even during periods of clinical silence. To quantify the metabolic characteristics of this activity we compared the absolute levels of N -acetylaspartate (NAA), creatine (Cr), and choline (Cho) in the normal-appearing white matter (NAWM) between relapsing-remitting (RR) MS patients and controls. Metabolite concentrations were obtained with 3D proton MR spectroscopy at 1.5 T in a 480 cm3 volume-of-interest (VOI), centered on the corpus callosum of 11 MS patients and 9 matched controls. Gray/white-matter/cerebral-spinal-fluid (CSF) volumes were obtained from MRI segmentation. Patients' average VOI tissue volume (VT), 410.8 ± 24.0 cm3, and metabolite levels, NAA = 6.33 ± 0.70, Cr = 4.67 ± 0.52, Cho = 1.40 ± 0.17 mM, were different from the controls by ,8%, ,9%, +22% and +32%. The Cho level was the only single metric differentiating patients from controls at 100% specificity and >90% sensitivity. Diffusely elevated Cho and Cr probably reflect widespread microscopic inflammation, gliosis, or de- and remyelination in the NAWM. Both metabolites are potential prognostic indicators of current disease activity, preceding NAA decline and atrophy. Magn Reson Med 50:190,195, 2003. © 2003 Wiley-Liss, Inc. [source] Lentivirus vector-mediated gene transfer to the developing bronchiolar airway epithelium in the fetal lambTHE JOURNAL OF GENE MEDICINE, Issue 6 2007Ze-Yan Yu Abstract Background Development of effective and durable gene therapy for treatment of the respiratory manifestations of cystic fibrosis remains a formidable challenge. Obstacles include difficulty in achieving efficient gene transfer to mature airway epithelium and the need to stably transduce self-renewing epithelial progenitor cells in order to avoid loss of transgene expression through epithelial turnover. Targeting the developing airway epithelium during fetal life offers the prospect of circumventing these challenges. Methods In the current study we investigated vesicular stomatitis virus glycoprotein (VSVg)-pseudotyped HIV-1-derived lentivirus vector-mediated gene transfer to the airway epithelium of mid-gestation fetal lambs, both in vitro and in vivo. In the in vitro studies epithelial sheet explants and lung organ culture were used to examine transduction of the proximal and more distal airway epithelium, respectively. For the in vivo studies, vector was delivered directly into the proximal airway. Results We found that even during the early pseudoglandular and canalicular phases of lung development, occurring through mid-gestation, the proximal bronchial airway epithelium was relatively mature and highly resistant to lentivirus-mediated transduction. In contrast, the more distal bronchiolar airway epithelium was relatively permissive for transduction although the absolute levels achieved remained low. Conclusion This result is promising as the bronchiolar airway epithelium is a major site of pathology in the cystic fibrosis airway, and much higher levels of transduction are likely to be achieved by developing strategies that increase the amount of vector reaching the more distal airway after intratracheal delivery. Copyright © 2007 John Wiley & Sons, Ltd. [source] Transgene-activated mesenchymal cells for articular cartilage repair: a comparison of primary bone marrow-, perichondrium/periosteum- and fat-derived cellsTHE JOURNAL OF GENE MEDICINE, Issue 1 2006Jung Park Abstract Background Adult primary mesenchymal cells of different origin which can be obtained with minor donor site morbidity are considered for articular cartilage repair. This study aims at a comparison of their chondrogenic potential. Methods Mesenchymal cells were isolated from perichondrium/periosteum, bone marrow or fat of adult rats and found to be positive for the stem-cell-related antigens Sca-1, c-Kit, CD10, CD13 and CD90 by reverse transcription polymerase chain reaction (RT-PCR). Chondrogenic differentiation was induced by applying recombinant bone morphogenetic protein-2 (BMP-2) or adenoviral vectors carrying BMP-2 cDNA, followed by micromass culture. The stimulated cells were characterized by RT-PCR, cell proliferation and apoptosis assays. Expression of aggrecan, collagen type I, II, IX and X and alkaline phosphatase genes was analyzed by RT-PCR, immunofluorescence and immunohistochemistry in comparison with unstimulated control cells. Adenovirally stimulated cells were transplanted into mechanically generated partial-thickness cartilage lesions in the patellar groove of the rat femur. Quality and integration of the repair tissues were assessed by histochemical and immunohistochemical methods. Results Stimulation with BMP-2 or AdBMP-2 led to an up-regulation of cartilage-specific gene expression in all three cell populations studied, most rapidly and prominently in the perichondrial/periosteal cells, which showed a 3200-fold increase of type II collagen mRNA and reached the highest absolute levels of type II and IX collagen transcripts after stimulation. Similar results were obtained for the bone marrow stromal cells (BMSC), while the respective transcript levels in fat stromal cells declined after an initial more than 30-fold elevation. Following transplantation in vivo, AdBMP-2-infected perichondrial/periosteal cells produced a proteoglycan-rich, type II collagen-positive matrix with only faint staining for type I collagen. The repair tissue originating from AdBMP-2-infected BMSC showed less intense type II collagen staining, but a relatively proteoglycan-rich matrix, weakly positive for type I collagen. Transgene-activated fat stromal cells formed rather fibrous tissue mainly composed of type I collagen. Unstimulated cells of the three different populations gave only rise to fibrous tissue. Conclusions Perichondrium/periosteum-derived cells and BMSC seem superior to cells isolated from fat with respect to forming hyaline cartilaginous tissue. A chondrogenic stimulus, e.g. by transfer of BMP-2 cDNA, appears to be required for initiation and support of chondrogenic differentiation. Copyright © 2005 John Wiley & Sons, Ltd. [source] Angiopoietins in tumours: the angiogenic switchTHE JOURNAL OF PATHOLOGY, Issue 1 2004Catherine R Tait Abstract On first view, the literature pertaining to the expression of the angiopoietins in tumours is confusing and does not readily offer a consensus pattern. Apparently conflicting publications report increased, decreased or unchanged expression levels of both angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) in a wide range of tumours. However, closer scrutiny of the literature, taking into account relative increases or decreases of each factor, reveals a consensus pattern, seen in almost all instances of expression profiling of the angiopoietins in tumours. What becomes apparent is that although absolute levels of either angiopoietin may increase or decrease, the ratio of Ang-1:Ang-2 shifts in favour of Ang-2. Given that Ang-2 is a destabilization factor, rendering vasculature in a more plastic state amenable to sprouting (under the influence of vascular endothelial growth factor, VEGF) or regression, this analysis suggests that tumours shift the angiogenic balance towards a pro-angiogenic state through altering the balance between the angiopoietins. This in turn implicates Ang-2 as a candidate for the angiogenic switch and also as an important potential therapeutic target. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Reductions in basal limb blood flow and vascular conductance with human ageing: role for augmented ,-adrenergic vasoconstrictionTHE JOURNAL OF PHYSIOLOGY, Issue 3 2001Frank A. Dinenno 1Basal whole-limb blood flow and vascular conductance decrease with age in men. We determined whether these age-associated changes in limb haemodynamics are mediated by tonically augmented sympathetic ,-adrenergic vasoconstriction. 2Seven young (28 ± 2 years; mean ±s.e.m.) and eight older (64 ± 2 years) healthy, normotensive adult men were studied. Baseline femoral artery blood flow (Doppler ultrasound) and calculated vascular conductance were 29 and 31 % lower, respectively, and vascular resistance was 53 % higher in the older men (all P < 0.001). 3Local (intra-femoral artery) ,-adrenergic receptor blockade with phentolamine evoked greater increases in femoral blood flow (105 ± 11 vs. 60 ± 6 %) and vascular conductance (125 ± 13 vs. 66 ± 7 %), and reductions in vascular resistance (55 ± 2 vs. 39 ± 3 %) in the experimental limb of the older compared with the young men (all P < 0.001). As a result, ,-adrenergic receptor blockade eliminated the significance of the age-associated differences in absolute levels of femoral blood flow (500 ± 51 vs. 551 ± 35 ml min,1), vascular conductance (6.02 ± 0.73 vs. 6.33 ± 0.26 U), and vascular resistance (0.17 ± 0.03 vs. 0.16 ± 0.01 U; P= 0.4,0.8, n.s.). Femoral haemodynamics in the control limb were unaffected by phentolamine administration in the contralateral (experimental) limb. Complete ,-adrenergic receptor blockade was demonstrated by the absence of vasoconstriction in the experimental limb in response to the cold pressor test. Local propranolol was administered to control for any ,-adrenergic effects of phentolamine. Propranolol did not affect haemodynamics in the experimental or control limbs. 4Our results indicate that the age-related reductions in basal limb blood flow and vascular conductance are mediated largely by chronically elevated sympathetic ,-adrenergic vasoconstriction. This may have important physiological and pathophysiological implications for the ageing human. [source] Tree Diversity, Forest Structure and Productivity along Altitudinal and Topographical Gradients in a Species-Rich Ecuadorian Montane Rain ForestBIOTROPICA, Issue 2 2010Jürgen Homeier ABSTRACT We studied the spatial heterogeneity of tree diversity, and of forest structure and productivity in a highly diverse tropical mountain area in southern Ecuador with the aim of understanding the causes of the large variation in these parameters. Two major environmental gradients, elevation and topography, representing a broad range of climatic and edaphic site conditions, were analyzed. We found the highest species richness of trees in valleys <2100 m. Valleys showed highest values of basal area, leaf area index and tree basal area increment as well. Tree diversity also increased from ridges to valleys, while canopy openness decreased. Significant relationships existed between tree diversity and soil parameters (pH, total contents of Mg, K, Ca, N and P), and between diversity and the spatial variability of pH and Ca and Mg contents suggesting a dependence of tree diversity on both absolute levels and on the small-scale heterogeneity of soil nutrient availability. Tree diversity and basal area increment were positively correlated, partly because both are similarly affected by soil conditions. We conclude that the extraordinarily high tree species richness in the area is primarily caused by three factors: (1) the existence of steep altitudinal and topographic gradients in a rather limited area creating a small-scale mosaic of edaphically different habitats; (2) the intermingling of Amazonian lowland plant species, that reach their upper distribution limits, and of montane forest species; and (3) the geographical position of the study area between the humid eastern Andean slope and the dry interandean forests of South Ecuador. [source] General obstetrics: Failing pregnancies of unknown location: a prospective evaluation of the human chorionic gonadotrophin ratioBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 5 2006G Condous Objective, To assess the performance of the human chorionic gonadotrophin (hCG) ratio (hCG 48 hours/hCG 0 hour) to predict spontaneous resolution of pregnancies of unknown location (PUL). Design, Prospective cohort study. Setting, Teaching Hospital Early Pregnancy Unit. Population, Women classified as having a PUL. Methods, The optimal cutoff value for hCG ratio (serum hCG at 48 hours/serum hCG at 0 hours) was calculated from data on 189 consecutive PULs (the ,training set'). This cutoff was tested prospectively on a further 200 consecutive PULs (the ,test set'). The hCG ratio was also compared to absolute levels of serum hCG at 0 and 48 hour for the prediction of failing PULs. Main outcome measures, hCG ratio in spontaneously resolving (,failing') PUL compared with those requiring intervention. Optimum cutoff determined and tested to predict spontaneously resolving PUL. Comparison of hCG ratio with absolute levels of serum hCG. Results, A total of 3996 consecutive women were scanned, of which 438 (11.0%) were classified as PULs. Complete data were available for 389 women: 189 in the training set and 200 in the test set. In the training set, there were 102 (54%) failing PUL, while 109 (55%) in the test set. hCG ratio of <0.87 predicted failing PUL, with a sensitivity of 93.1% (95% CI 85.9,97.0) and a specificity of 90.8% (95% CI 82.2,95.7) in the training set. In the test set, sensitivity was 92.7% (95% CI 85.6,96.5) and specificity was 96.7% (95% CI 90.0,99.1). The hCG ratio outperformed absolute serum hCG levels at 0 and 48 hours. Conclusions, We have defined the optimal hCG ratio for the prediction of failing PUL. Using this cutoff, clinicians can safely adopt a noninterventional approach in women with PUL. [source] Complex regulation of choroidal blood flow during combined changes in blood pressure and IOPACTA OPHTHALMOLOGICA, Issue 2009L SCHMETTERER Purpose In the recent years it has been shown that the human choroid shows some regulatory capacity during an artifical increase in intraocular pressure (IOP) as well as during an exercise induced increase in mean arterial pressure (MAP). The purpose of the present study was to test the hypothesis that human choroidal blood flow (ChBF) may depend, not only on ocular perfusion pressure (OPP), but also on absolute levels of MAP and IOP. Methods In a clinical study in 28 helathy subjects OPP was varied by elevating IOP during a squatting-induced increase in MAP. IOP was raised in stepwise increments by using the suction cup method. Subfoveal choroidal blood flow (VhBF, laser Doppler flowmetry), MAP, and IOP were assessed, and OPP was calculated as (2/3)(MAP - IOP). For correlation analysis, data from all subjects were pooled according to IOP and MAP values, and correlation analyses were performed. Results When data were grouped according to IOP, no correlation was observed between ChBF and MAP; but ChBFs were lower, the higher the IOP (P < 0.001). When data were grouped according to MAP, a significant correlation was found between ChBF and IOP (P < 0.001), but correlations were independent of MAP. Conclusion These data confirm previously published observations that the choroid shows some regulatory capacity during changes in OPP. In addition, the data indicate that the choroid regulates its blood flow better during exercise-induced changes in MAP than during an experimental increase in IOP. [source] | |||||||||||||||||||