Abstract:
:The drought of progress in clinical brain tumor therapy provides an impetus for developing new treatments as well as methods for testing therapeutics in animal models. The inability of traditional assays to simultaneously measure tumor size, location, growth kinetics, and cell kill achieved by a treatment complicates the interpretation of therapy experiments in animal models. To address these issues, tumor volume measurements obtained from serial magnetic resonance images were used to noninvasively estimate cell kill values in individual rats with intracerebral 9L tumors after treatment with 0.5, 1, or 2 x LD10 doses of 1,3-bis(2-chloroethyl)-1-nitrosourea. The calculated cell kill values were consistently lower than those reported using traditional assays. A dose-dependent increase in 9L tumor doubling time after treatment was observed that significantly contributed to the time required for surviving cells to repopulate the tumor mass. This study reveals that increases in animal survival are not exclusively attributable to the fraction of tumor cells killed but rather are a function of the cell kill and repopulation kinetics, both of which vary with treatment dose.
journal_name
Proc Natl Acad Sci U S Aauthors
Ross BD,Zhao YJ,Neal ER,Stegman LD,Ercolani M,Ben-Yoseph O,Chenevert TLdoi
10.1073/pnas.95.12.7012subject
Has Abstractpub_date
1998-06-09 00:00:00pages
7012-7issue
12eissn
0027-8424issn
1091-6490journal_volume
95pub_type
杂志文章abstract::Infective stages of the protozoan parasite Leishmania spp. accumulate a class of beta-1,2-mannan oligosaccharides as their major carbohydrate reserve material. Here, we describe the biosynthesis of Leishmania mannan. Mannan precursors were identified by metabolic labeling of Leishmania mexicana promastigotes with [(3)...
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.0603539103
更新日期:2006-06-20 00:00:00
abstract::Eukaryotic cells require N-linked carbohydrates for survival. However, the biosynthetic intermediate Man5GlcNAc2Asn, in place of mature N-linked structures, allows glycoprotein synthesis and somatic cell growth to proceed normally. To determine whether the same would be true in a complex biological situation, the gene...
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.91.2.728
更新日期:1994-01-18 00:00:00
abstract::The roles of glycosylation and protein synthesis in the maintenance of insulin receptor levels and turnover rates in 3T3-L1 adipocytes were investigated. The heavy isotope density-shift technique was employed to determine the effects of inhibitors of these processes on the rates of synthesis and degradation of cellula...
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.78.5.2908
更新日期:1981-05-01 00:00:00
abstract::For many agronomically important plant genes, only their position on a genetic map is known. In the absence of an efficient transposon tagging system, such genes have to be isolated by map-based cloning. In bread wheat Triticum aestivum, the genome is hexaploid, has a size of 1.6 x 10(10) bp, and contains more than 80...
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.230361597
更新日期:2000-11-21 00:00:00
abstract::The semidwarf phenotype has been extensively selected during modern crop breeding as an agronomically important trait. Introduction of the semidwarf gene, semi-dwarf1 (sd1), which encodes a gibberellin biosynthesis enzyme, made significant contributions to the "green revolution" in rice (Oryza sativa L.). Here we repo...
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.1019490108
更新日期:2011-07-05 00:00:00
abstract::We have determined the nucleotide sequences of cDNAs encoding the precursor of the beta subunit of rat lutropin, a polypeptide hormone that regulates gonadal function, including the development of gametes and the production of steroid sex hormones. The cDNAs were prepared from poly(A)+ RNA derived from the pituitary 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.80.15.4649
更新日期:1983-08-01 00:00:00
abstract::New neurons are generated in adult mammalians and may contribute to repairing the brain after injury. Here, we show that the number of new neurons in the dentate gyrus of adult rats increased in cerebral ischemic stroke and correlated with activation of the cAMP-response-element-binding protein (CREB). Inhibition of e...
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.0401063101
更新日期:2004-06-22 00:00:00
abstract::Growing knowledge of the key molecular components involved in biological processes such as endocytosis, exocytosis, and motility has enabled direct testing of proposed mechanistic models by reconstitution. However, current techniques for building increasingly complex cellular structures and functions from purified com...
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.1016410108
更新日期:2011-06-07 00:00:00
abstract::Although Wingless (Wg)/Wnt signaling has been implicated in heart development of multiple organisms, conflicting results have been reported regarding the role of Wnt/beta-catenin pathway in cardiac myogenesis: Wg/armadillo signaling promotes heart development in Drosophila, whereas activation of Wnt/beta-catenin signa...
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.0605768103
更新日期:2006-12-26 00:00:00
abstract::Immobilization antigens of stock 51 of Paramecium tetraurelia were subjected to electrophoresis in NaDodSO(4)/polyacrylamide gels. Type A is estimated to have a molecular size of 300,000 daltons; H is estimated to be 288,000, D to be 280,000, E to be 270,000, B to be 253,000, and C to be 250,000. Poly(A)(+)RNAs have b...
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.78.11.6776
更新日期:1981-11-01 00:00:00
abstract::[3H]Thymidine-labeled progeny DNA was isolated after infection of Escherichia coli with two different bacteriophage T4 mutants. These strands were isolated shortly after the initiation of DNA replication and hybridized to 15 different (EcoRI) T4 restriction fragments cloned in plasmid vectors. Uniformly labeled T4 [32...
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.76.12.6137
更新日期:1979-12-01 00:00:00
abstract::Most evidence supports the view that ER alpha is responsible for estrogen (ovarian estradiol, E(2))-induced proliferation in the epithelial cells of the mammary gland, but despite this, proliferating epithelial cells do not express ER alpha. We have examined this apparent paradox by studying the role of ER alpha and E...
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.0307864100
更新日期:2004-03-16 00:00:00
abstract::Arc repressor forms a homodimer in which the subunits intertwine to create a single globular domain. To obtain Arc sequences that fold preferentially as heterodimers, variants with surface patches of excess positive or negative charge were designed. Several but not all oppositely charged sequence pairs showed preferen...
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.051624498
更新日期:2001-03-13 00:00:00
abstract::Mutations induced by (+/-)trans-benzo-[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BaP-diol epoxide-1) were selected by using a recombinant plasmid vector system designed for the study of transcription termination signals. The plasmid contains a transcription terminator positioned between a promotor signal and the Escheric...
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.78.11.6817
更新日期:1981-11-01 00:00:00
abstract::Lipid-soluble spin labels were incorporated into human lymphocytes and mouse L-cells and the resulting electron spin resonance spectra were compared with spectra obtained from similarly labeled human erythrocytes. Spin labels were found in all subcellular fractions of the nucleated cells that contained membranes. Spin...
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.70.1.66
更新日期:1973-01-01 00:00:00
abstract::The resonance Raman excitation profiles of a number of charge transfer transitions in electron donor/acceptor complexes with tetracyanoethylene as acceptor in solution at room temperature are reported and compared with absorption and fluorescence spectra of these complexes. All complexes show distinct anomalies which ...
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.72.11.4196
更新日期:1975-11-01 00:00:00
abstract::The fundamental questions of how lubricant molecules organize into a layered structure under nanometers confinement and what is the interplay between layering and friction are still not well answered in the field of nanotribology. While the phase transition of lubricants during a squeeze-out process under compression ...
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.1805569115
更新日期:2018-06-26 00:00:00
abstract::It is commonly accepted that some of the latest dates for Neanderthal fossils and Mousterian industries are found south of the Ebro valley in Iberia at ca. 36 ka calBP (calibrated radiocarbon date ranges). In contrast, to the north of the valley the Mousterian disappears shortly before the Proto-Aurignacian appears at...
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.1207656110
更新日期:2013-02-19 00:00:00
abstract::Hermansky-Pudlak syndrome (HPS) defines a group of autosomal recessive disorders characterized by deficiencies in lysosome-related organelles such as melanosomes and platelet-dense granules. Several HPS genes encode proteins of unknown function including HPS1, HPS3, and HPS4. Here we have identified and characterized ...
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.1532040100
更新日期:2003-07-22 00:00:00
abstract::The long-lived ethylene, cyclohexene, and norbornenemercurinium ions prepared in superacidic, low-nucleophilic media have been studied by (13)C and (199)Hg NMR spectroscopy. The norbornenemercurinium ion shows temperature-dependent (13)C and (199)Hg NMR spectra, consistent with equilibration via rapid hydride and Wagn...
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.77.9.5036
更新日期:1980-09-01 00:00:00
abstract::Ankyrin-G (AnkG), a highly enriched scaffold protein in the axon initial segment (AIS) of neurons, functions to maintain axonal polarity and the integrity of the AIS. At the AIS, AnkG regulates selective intracellular cargo trafficking between soma and axons via interaction with the dynein regulator protein Ndel1, but...
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.1916987117
更新日期:2020-01-14 00:00:00
abstract::Neutrophils are important effector cells in immunity to microorganisms, particularly bacteria. Here, we show that the process of neutrophil apoptosis is delayed in several inflammatory diseases, suggesting that this phenomenon may represent a general feature contributing to the development of neutrophilia, and, theref...
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.96.23.13330
更新日期:1999-11-09 00:00:00
abstract::The leukotrienes C4, D4, and E4, previously referred to as slow reacting substance of anaphylaxis, elicited long-lasting contractions of bronchi isolated from two birch pollen-sensitive asthmatics. The leukotrienes were 1,000 times more potent on a molar basis than was histamine or prostaglandin F2 alpha. Moreover, al...
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.80.6.1712
更新日期:1983-03-01 00:00:00
abstract::We performed label-free observation of molecular dynamics in apoptotic cells by Raman microscopy. Dynamic changes in cytochrome c distribution at the Raman band of 750 cm(-1) were observed after adding an apoptosis inducer to the cells. The comparison of mitochondria fluorescence images and Raman images of cytochrome ...
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.1107524108
更新日期:2012-01-03 00:00:00
abstract::Pain reduction and enhancement can be produced by means of conditioning procedures, yet the role of awareness during the acquisition stage of classical conditioning is unknown. We used psychophysical measures to establish whether conditioned analgesic and hyperalgesic responses could be acquired by unseen (subliminall...
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.1504567112
更新日期:2015-06-23 00:00:00
abstract::Duplexes of 21-nt RNAs, known as short-interfering RNAs (siRNAs), efficiently inhibit gene expression by RNA interference (RNAi) when introduced into mammalian cells. We show that siRNAs can be synthesized by in vitro transcription with T7 RNA polymerase, providing an economical alternative to chemical synthesis of si...
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.092143499
更新日期:2002-04-30 00:00:00
abstract::The activation of plant defensive genes in leaves of tomato plants in response to herbivore damage or mechanical wounding is mediated by a mobile 18-amino acid polypeptide signal called systemin. Systemin is derived from a larger, 200-amino acid precursor called prosystemin, similar to polypeptide hormones and soluble...
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.93.22.12053
更新日期:1996-10-29 00:00:00
abstract::125I-Labeled L-fucose-albumin complex and rat preputial beta-glucuronidase are rapidly cleared from plasma after intravenous infusion. L-Fucose-albumin retards the plasma clearance of beta-glucuronidase whereas D-fucose-albumin is inactive. In vitro, 125I-labeled L-fucose-albumin is taken up into rat or rabbit alveola...
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.78.2.1019
更新日期:1981-02-01 00:00:00
abstract::The virB operon of the Agrobacterium tume-faciens pTiA6NC plasmid likely plays a role in directing T-DNA transfer events at the bacterial membrane, as determined previously by mutagenesis and cellular fractionation studies and by DNA sequence analysis of the approximately 12-kilobase-pair operon. The DNA sequence anal...
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.86.24.9677
更新日期:1989-12-01 00:00:00
abstract::Human Bestrophin 1 (hBest1) is a calcium-activated chloride channel that regulates neuronal excitability, synaptic activity, and retinal homeostasis. Mutations in hBest1 cause the autosomal-dominant Best macular dystrophy (BMD). Because hBest1 mutations cause BMD, but a knockout does not, we wondered if hBest1 mutants...
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.1400248111
更新日期:2014-04-29 00:00:00