Abstract:
:High-affinity nuclear binding sites for 17 beta-estradiol (17 beta E2) were recently found in bone cells; however, the mechanism by which estrogen exerts its effect on bone in vivo is still unknown. To study if estrogen acts on bone directly, we used an experimental model in which test substances are infused locally into rat femur trabecular bone. Sprague-Dawley rats weighing 150-160 g were ovariectomized (OVX) and 14 days later a polyethylene tube (1 mm in diameter) connected to an Alzet osmotic minipump was implanted into the distal femur 9 mm from the joint. 17 beta E2 (24 microliters/day at 0.01-1 nM), 17 alpha-estradiol (17 alpha E2) (24 microliters/day at 1 nM), or phosphate-buffered saline (NaCl, 8 g/liter; KCl, 0.2 g/liter; KH2PO4, 0.2 g/liter; Na2HPO4.7H2O, 2.16 g/liter) was infused for 8 days. The contralateral limb remained intact. Animals were sacrificed and bones were examined by histomorphometry. Ovariectomy caused a 50% loss in trabecular bone volume (TBV) in the secondary spongiosa (from 20.3% +/- 1.7% to 9.6% +/- 1.1%; mean +/- SEM), a 2-fold increase in osteoclast number (to 4.0 +/- 0.4 per mm), a 3-fold increase in relative resorption surfaces (to 24.8% +/- 2.9%), a 9-fold increase in osteoblast number (to 11.3 +/- 2.1 per mm), and an 8-fold increase in relative osteoid surface (to 9.6% +/- 1.7%). The local infusion of 17 beta E2 for 8 days into OVX rats (i) restored the TBV dose dependently to 75% and 85% of control (non-OVX) levels, at 0.1 nM and 1 nM 17 beta E2, respectively; (ii) decreased osteoclast number and the relative resorption surface to control (non-OVX) levels; and (iii) further increased osteoblast number and the relative osteoid surface dose dependently (by 5-fold at 1 nM 17 beta E2). Phosphate-buffered saline infusion was without effect. Infusion of 17 alpha E2 had no effect on TBV, osteoclast number, or resorption surface but increased slightly the osteoblast number and the osteoid surface. Its potency was 1/100 that of 17 beta E2. The local infusion of 17 beta E2 or 17 alpha E2 had no effect on body or uterine weight. We conclude from these findings that estrogen delivered directly to the bone of OVX rats in vivo at 2.4 and 24 fmol/day acted locally to inhibit bone resorption and stimulate bone formation.
journal_name
Proc Natl Acad Sci U S Aauthors
Takano-Yamamoto T,Rodan GAdoi
10.1073/pnas.87.6.2172subject
Has Abstractpub_date
1990-03-01 00:00:00pages
2172-6issue
6eissn
0027-8424issn
1091-6490journal_volume
87pub_type
杂志文章abstract::Mutant, but not wild-type p53 binds with high affinity to a variety of MAR-DNA elements (MARs), suggesting that MAR-binding of mutant p53 relates to the dominant-oncogenic activities proposed for mutant p53. MARs recognized by mutant p53 share AT richness and contain variations of an AATATATTT "DNA-unwinding motif," w...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.23.13681
更新日期:1998-11-10 00:00:00
abstract::The traditional disciplines of science are grounded in the observation and measurement of object properties. Recent advances in digital computer technology have spawned numerous computer-based imaging systems that extend the range of observation and measurement into realms that would otherwise be inaccessible. More im...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.21.9746
更新日期:1993-11-01 00:00:00
abstract::The two major disease-causing biotypes of Vibrio cholerae, classical and El Tor, exhibit differences in their epidemic nature. Their behavior in the laboratory also differs in that El Tor strains produce two major virulence factors, cholera toxin (CT) and the toxin coregulated pilus (TCP), only under very restricted g...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.15.7991
更新日期:1996-07-23 00:00:00
abstract::The candidate phylum TM7 is globally distributed and often associated with human inflammatory mucosal diseases. Despite its prevalence, the TM7 phylum remains recalcitrant to cultivation, making it one of the most enigmatic phyla known. In this study, we cultivated a TM7 phylotype (TM7x) from the human oral cavity. Th...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1419038112
更新日期:2015-01-06 00:00:00
abstract::Animals are associated with a microbiome that can affect their reproductive success. It is, therefore, important to understand how a host and its microbiome coevolve. According to the hologenome concept, hosts and their microbiome form an integrated evolutionary entity, a holobiont, on which selection can potentially ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1909790116
更新日期:2019-10-08 00:00:00
abstract::Transmission electron microscope images were obtained of fractions of poly(1-tetradecene sulfone) and poly(cyclohexene sulfone) cast from very dilute solutions (0.007%, wt/vol) and rapidly freeze-dried on a mica surface. The samples were then vertically platinum-carbon (Pt-C) replicated with 9 +/- 0.3-A Pt-C and held ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.89.17.7991
更新日期:1992-09-01 00:00:00
abstract::A specific antibody against proinsulin has been obtained by adsorbing the original anti-proinsulin guinea pig serum with a solid immunosorbent of Sephadex-insulin. The specificity of the antibody against antigenic determinants of proinsulin was established by radioimmunoassay and by passive cutaneous anaphylaxis (PCA)...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.62.2.415
更新日期:1969-02-01 00:00:00
abstract::Up to half of all transcription termination events in bacteria rely on the RNA-dependent helicase Rho. However, the nucleic acid sequences that promote Rho-dependent termination remain poorly characterized. Defining the molecular determinants that confer Rho-dependent termination is especially important for understand...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1319193111
更新日期:2014-05-13 00:00:00
abstract::The effects of divalent ionophores (A23187 and ionomycin), Ca2+ channel agonist (BAY K 8644), and protein kinase C (C-kinase) activators [phorbol 12-myristate 13-acetate (PMA), mezerein] on bovine tracheal smooth muscle contraction were investigated. A23187 (5 microM) and ionomycin (0.5 microM) produced a prompt but t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.24.8835
更新日期:1985-12-01 00:00:00
abstract::The promoter of the bean PAL2 gene (encoding phenylalanine ammonia-lyase; EC 4.3.1.5) is a model for studies of tissue-restricted gene expression in plants. Petal epidermis is one of the tissues in which this promoter is activated in tobacco. Previous work suggested that a major factor establishing the pattern of PAL2...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.15.6901
更新日期:1995-07-18 00:00:00
abstract::Pseudomonas aeruginosa is an opportunistic pathogen that requires preexisiting epithelial injury to cause acute infections. We report that P. aeruginosa inhibits mammalian cytokinesis in a type III secretion system and exotoxin T (ExoT)-dependent manner. ExoT is a bifunctional type III secretion system effector protei...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0605949103
更新日期:2006-10-17 00:00:00
abstract::The skeletal muscle L-type Ca2+ channel is a complex of five subunits that is specifically localized in the triad. Its primary function is the rapid activation of Ca2+ release from cytoplasmic stores in a process called excitation-contraction coupling. To study the role of alpha1S-beta1a interactions in the incorporat...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.9.5015
更新日期:1998-04-28 00:00:00
abstract::Olfactory receptor (OR) genes are of vital importance for animals to find food, identify mates, and avoid dangers. In mammals, the number of OR genes is large and varies extensively among different orders, whereas, in insects, the extent of interspecific variation appears to be small, although only a few species have ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0702133104
更新日期:2007-04-24 00:00:00
abstract::The thesis is developed that a low oxygen level Precambrian atmosphere presented early-evolving metazoan organisms with physiological connective tissue priorities resulting from the important molecular oxygen requirements in the biosynthesis of collagen hydroxyproline. Shells, cuticles, and carapaces which are not man...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.65.4.781
更新日期:1970-04-01 00:00:00
abstract::For beta-D-glucosylisophosphoramide mustard (beta-D-Glc-IPM), a new alkylating drug in which isophosphoramide mustard is stabilized, a higher selectivity and lower myelotoxicity was observed than for the currently used cytostatic ifosfamide. Because beta-D-Glc-IPM is hydrophilic and does not diffuse passively through ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.6.2914
更新日期:1998-03-17 00:00:00
abstract::The retinal pigment epithelium (RPE) plays a critical role in the maintenance of the outer retina. RPE cell death or dysfunction drives the pathophysiology of many retinal diseases, but the physiological response of the retina to RPE cell loss is poorly understood, mainly because of the absence of suitable experimenta...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0902593106
更新日期:2009-11-03 00:00:00
abstract::Amphibian eggs and embryos as well as mammalian cells have been reported to contain an activity that unwinds double-stranded RNA. We have now found that adenosine residues have been modified in the RNA products of this unwinding activity. Although the modified RNA remains double-stranded, the modification causes the R...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.8.2647
更新日期:1989-04-01 00:00:00
abstract::Several polypeptides contained in the coat and the core of adenovirus type 2 particles have been identified as virus gene products. They are synthesized in vitro by a cell-free protein-making system programmed by adenovirus type 2 messenger RNA that has been hybridized with and eluted from virus DNA. Fractionation by ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.71.9.3385
更新日期:1974-09-01 00:00:00
abstract::Changes in external light patterns can alter cell activities in peripheral tissues through slow entrainment of the central clock in suprachiasmatic nucleus (SCN). It remains unclear whether cells in otherwise photo-insensitive tissues can achieve rapid responses to changes in external light. Here we show that light st...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1719548115
更新日期:2018-07-17 00:00:00
abstract::We review a program of research that uses neuroimaging techniques to determine the functional and neural architecture of human working memory. A first set of studies indicates that verbal working memory includes a storage component, which is implemented neurally by areas in the left-hemisphere posterior parietal corte...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.95.20.12061
更新日期:1998-09-29 00:00:00
abstract::The electrophysiological basis for higher brain activity during rest and internally directed cognition within the human default mode network (DMN) remains largely unknown. Here we use intracranial recordings in the human posteromedial cortex (PMC), a core node within the DMN, during conditions of cued rest, autobiogra...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1017098108
更新日期:2011-02-15 00:00:00
abstract::Ca(V)1 channels initiate excitation-contraction coupling in skeletal and cardiac muscle. During the fight-or-flight response, epinephrine released by the adrenal medulla and norepinephrine released from sympathetic nerves increase muscle contractility by activation of the β-adrenergic receptor/cAMP-dependent protein k...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1012384107
更新日期:2010-10-26 00:00:00
abstract::Lampreys are one of the two surviving jawless vertebrate groups and one of a few vertebrate groups with the best exemplified metamorphosis during their life cycle, which consists of a long-lasting larval stage, a peculiar metamorphosis, and a relatively short adulthood with a markedly different anatomy. Although the f...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1415716111
更新日期:2014-10-28 00:00:00
abstract::We provide a framework for structural multiscale geometric organization of graphs and subsets of R(n). We use diffusion semigroups to generate multiscale geometries in order to organize and represent complex structures. We show that appropriately selected eigenfunctions or scaling functions of Markov matrices, which d...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0500334102
更新日期:2005-05-24 00:00:00
abstract::Chlorarachniophytes are amoeboid algae with unusual chloroplasts. Instead of the usual two membranes that surround the chloroplasts of plants, green algae, and red algae, the chloroplasts of chlorarachniophytes have four bounding membranes. The extra membranes may reflect an unusual origin of chlorarachniophyte chloro...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.9.3690
更新日期:1994-04-26 00:00:00
abstract::Transient Receptor Potential Melastatin-8 (TRPM8), a recently identified member of the transient receptor potential (TRP) family of ion channels, is activated by mild cooling and by chemical compounds such as the supercooling agent, icilin. Since cooling, possibly involving TRPM8 stimulation, diminishes injury-induced...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1217431110
更新日期:2013-04-30 00:00:00
abstract::We have cloned a member of the nuclear receptor superfamily. The cDNA was isolated from a rat liver library and encodes a protein of 446 aa with a predicted mass of 50 kDa. This clone (OR-1) shows no striking homology to any known member of the steroid/thyroid hormone receptor superfamily. The most related receptor is...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.6.2096
更新日期:1995-03-14 00:00:00
abstract::Cells obtained from normal human skin synthesize predominantly type I collogen in culture. Cells obtained from the skin of an infant with a severe form of osteogenesis imperfecta were found to synthesize as much type III as type I collagen. Decreased synthesis of type I collagen could explain the tissue fragility obse...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.72.2.586
更新日期:1975-02-01 00:00:00
abstract::Effects of opiate receptor antagonists on centrally mediated cardiovascular responses to clonidine and beta-endorphin were studied in urethane-anesthetized spontaneously hypertensive Okamoto-Aoki rats (SHR), normotensive Sprague-Dawley rats, and Sprague-Dawley rats made hypertensive with deoxycorticosterone pivalate/s...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.23.8637
更新日期:1987-12-01 00:00:00
abstract::Two chlorophyll-protein complexes associated with photosystem II (PSII) of the cyanobacterium Anacystis nidulans R2 have been detected. The larger of the two complexes, CPVI-1, contained a 71-kDa and a 42-kDa protein. The 71-kDa protein was determined to be the anchor protein of the phycobilisomes (the light-harvestin...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.20.6903
更新日期:1985-10-01 00:00:00