205 research outputs found
α<sub>1L</sub>-adrenoceptors mediate contraction of human erectile tissue
α1-adrenoceptor antagonists can impact upon sexual function and have potential in the treatment of erectile dysfunction. Human erectile tissue contains predominantly α1A-adrenoceptors, and here we examined whether contractions of this tissue are mediated by the functional phenotype, the α1L-adrenoceptor. Functional experiments using subtype selective agonists and antagonists, along with radioligand ([3H]tamsulosin) binding assays, were used to determine the α1-adrenoceptor population. A61603, a α1A-adrenoceptor agonist, was a full agonist with a potency 21-fold greater than that of noradrenaline. The α1A- and α1D-adrenoceptor antagonist tamsulosin antagonized noradrenaline responses with high affinity (pKD = 9.7 ± 0.3), whilst BMY7378 (100 nM) (α1D-adrenoceptor antagonist) failed to antagonize responses. In contrast, relatively low affinity estimates were obtained for both prazosin (pKD = 8.2 ± 0.1) and RS17053 (pKD = 6.9 ± 0.2), antagonists which discriminate between the α1A- and α1L-adrenoceptors. [3H]Tamsulosin bound with high affinity to the receptors of human erectile tissue (pKD = 10.3 ± 0.1) with a receptor density of 28.1 ± 1.4 fmol mg−1 protein. Prazosin displacement of [3H]tamsulosin binding revealed a single homogenous population of binding sites with a relatively low affinity for prazosin (pKi = 8.9). Taken together these data confirm that the receptor mediating contraction in human erectile tissue has the pharmacological properties of the α1L-adrenoceptor. Keywords: Erectile tissue, α1-adrenoceptor subtypes, α1L-adrenoceptor, Tamsulosin, Prazosi
Rethinking cultural hybridity and technology transfer: SEM microstructural analysis of lead glazed ceramics from early colonial Peru
Through Scanning Electron Microscopy (SEM) microstructural analysis, we examine the firing technology of Early Green Glazed (EGG) Ware – a variety of “hybrid” lead-glazed ceramics produced in Peru's north coast region during the 16th century CE. Previous scholars have interpreted EGG Ware as the product of indigenous potters who fired ceramics in kilns and learned how to make glazed vessels through direct instruction from Iberian ceramicists. We argue that the production of EGG Ware entailed a more complex process of technological incorporation and innovation. SEM microstructural analysis of 44 archaeological samples suggests that these ceramics were originally fired under highly variable conditions. Parallel analysis of five samples of lead-glazed ceramics produced in open firings by Peruvian artisans in the 1980's reveals consistent firing beyond their clays' maturation temperatures. Based on these results and analysis of whole EGG Ware vessels from museum collections, we suggest that at least some of our EGG Ware samples were produced in open firings. In turn, we argue that EGG Ware reflects the creativity of native potters who adapted indigenous firing technologies and experimented with different parameters in the process of forging a new decorative tradition
Accurate ab initio spin densities
We present an approach for the calculation of spin density distributions for
molecules that require very large active spaces for a qualitatively correct
description of their electronic structure. Our approach is based on the
density-matrix renormalization group (DMRG) algorithm to calculate the spin
density matrix elements as basic quantity for the spatially resolved spin
density distribution. The spin density matrix elements are directly determined
from the second-quantized elementary operators optimized by the DMRG algorithm.
As an analytic convergence criterion for the spin density distribution, we
employ our recently developed sampling-reconstruction scheme [J. Chem. Phys.
2011, 134, 224101] to build an accurate complete-active-space
configuration-interaction (CASCI) wave function from the optimized matrix
product states. The spin density matrix elements can then also be determined as
an expectation value employing the reconstructed wave function expansion.
Furthermore, the explicit reconstruction of a CASCI-type wave function provides
insights into chemically interesting features of the molecule under study such
as the distribution of - and -electrons in terms of Slater
determinants, CI coefficients, and natural orbitals. The methodology is applied
to an iron nitrosyl complex which we have identified as a challenging system
for standard approaches [J. Chem. Theory Comput. 2011, 7, 2740].Comment: 37 pages, 13 figure
Shwachman-Bodian-Diamond syndrome (SBDS) protein is a direct inhibitor of protein phosphatase 2A (PP2A) activity and overexpressed in acute myeloid leukaemia.
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase inactivated in many cancers including acute myeloid leukaemia (AML). Activation of PP2A is emerging as a therapeutic strategy, however the mechanisms underpinning PP2A inhibition are not well understood. Using myeloid progenitor cells harbouring oncogenic mutant c-KIT and characterised by PP2A inhibition, we have identified the ribosome biogenesis protein SBDS, as a target of the PP2A activating drugs FTY720 and AAL(S). We show SBDS binds to PP2A complexes comprised of the B55α regulatory subunit of PP2A. shRNA mediated knockdown of SBDS increased PP2A activity and induced apoptosis. At diagnosis, AML patients expressed significantly more SBDS mRNA than healthy controls, with relapsed patients expressing significantly more SBDS mRNA than both healthy controls and patients at diagnosis. Together, our data presents a role for SBDS in the dysregulation of PP2A in AML
Using the present to interpret the past: the role of ethnographic studies in Andean archaeology
Within Andean research it is common to use ethnographic analogies to aid the interpretation of archaeological remains, and ethnographers and archaeologists have developed shared research in technology, material culture and material practice. Although most of this research does not follow the detailed recording methods of spatial patterning envisioned in earlier formulations of ethnoarchaeology, it has had a profound effect on how archaeology in the region has been interpreted. This paper uses examples from the study of pottery production to address earlier debates about the use of ethnographic analogy, discusses the dangers of imposing an idealised or uniform vision of traditional Andean societies onto earlier periods (‘Lo Andino’) but stresses the benefits of combining ethnographic and archaeological research to explore continuities and changes in cultural practice and regional variations
Persistent Place-Making in Prehistory: the Creation, Maintenance, and Transformation of an Epipalaeolithic Landscape
Most archaeological projects today integrate, at least to some degree, how past people engaged with their surroundings, including both how they strategized resource use, organized technological production, or scheduled movements within a physical environment, as well as how they constructed cosmologies around or created symbolic connections to places in the landscape. However, there are a multitude of ways in which archaeologists approach the creation, maintenance, and transformation of human-landscape interrelationships. This paper explores some of these approaches for reconstructing the Epipalaeolithic (ca. 23,000–11,500 years BP) landscape of Southwest Asia, using macro- and microscale geoarchaeological approaches to examine how everyday practices leave traces of human-landscape interactions in northern and eastern Jordan. The case studies presented here demonstrate that these Epipalaeolithic groups engaged in complex and far-reaching social landscapes. Examination of the Early and Middle Epipalaeolithic (EP) highlights that the notion of “Neolithization” is somewhat misleading as many of the features we use to define this transition were already well-established patterns of behavior by the Neolithic. Instead, these features and practices were enacted within a hunter-gatherer world and worldview
Ontogeny of central serotonergic neurons in the directly developing frog, Eleutherodactylus coqui
Embryonic development of the central serotonergic neurons in the directly developing frog, Eleutherodactylus coqui , was determined by using immunocytochemistry. The majority of anuran amphibians (frogs) possess a larval stage (tadpole) that undergoes metamorphosis, a dramatic post-embryonic event, whereby the tadpole transforms into the adult phenotype. Directly developing frogs have evolved a derived life-history mode where the tadpole stage has been deleted and embryos develop directly into the adult bauplan. Embryonic development in E. coqui is classified into 15 stages (TS 1–15; 1 = oviposition / 15 = hatching). Serotonergic immunoreactivity was initially detected at TS 6 in the raphe nuclei in the developing rhombencephalon. At TS 7, immunopositive perikarya were observed in the paraventricular organ in the hypothalamus and reticular nuclei in the hindbrain. Development of the serotonergic system was steady and gradual during mid-embryogenesis. However, starting at TS 13 there was a substantial increase in the number of serotonergic neurons in the paraventricular, raphe, and reticular nuclei, a large increase in the number of varicose fibers, and a differentiation of the reticular nuclei in the hindbrain. Consequentially, E. coqui displayed a well-developed central serotonergic system prior to hatching (TS 15). In comparison, the serotonergic system in metamorphic frogs typically starts to develop earlier but the surge of development that transpires in this system occurs post-embryonically, during metamorphosis, and not in the latter stages of embryogenesis, as it does in E. coqui . Overall, the serotonergic development in E. coqui is similar to the other vertebrates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47526/1/429_2005_Article_22.pd
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Pottery's role in the reproduction of Andean society
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