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1

Anti-cytokine auto-vaccinations as tools for the analysis of cytokine function in vivo.  

PubMed

Braking B cell tolerance to generate antibodies against autologous cytokines or chemokines offers an alternative to gene inactivation for functional analysis of these factors in vivo. It is clearly less potent than the genetic approach but offers the advantage of extreme flexibility. The basic principle is to enable a self-reactive B cell to attract T cell help by presenting foreign peptides, a process we called "deceptive" antigen presentation. We here review the different auto-vaccine procedures that are currently used and provide several examples of functional information acquired by this procedure or by mAbs derived from auto-vaccinated mice. PMID:22236653

Uyttenhove, Catherine; Van Snick, Jacques

2012-01-01

2

Rapid in vivo functional analysis of transgenes in mice using whole body imaging of luciferase expression  

Microsoft Academic Search

The use of transgenic animals in biomedical research is increasing rapidly and may be the best means of determining gene function. Generating transgenic animals typically requires time-consuming screening processes, and gene function is assessed by an array of difficult phenotypic and biochemical assays performed ex vivo. To address the unmet need in transgenic research for functional assays performed with ease

Weisheng Zhang; Jian Q. Feng; Stephen E. Harris; Pamela R. Contag; David K. Stevenson; Christopher H. Contag

2001-01-01

3

Molecular motor function in axonal transport in vivo probed by genetic and computational analysis in Drosophila  

PubMed Central

Bidirectional axonal transport driven by kinesin and dynein along microtubules is critical to neuronal viability and function. To evaluate axonal transport mechanisms, we developed a high-resolution imaging system to track the movement of amyloid precursor protein (APP) vesicles in Drosophila segmental nerve axons. Computational analyses of a large number of moving vesicles in defined genetic backgrounds with partial reduction or overexpression of motor proteins enabled us to test with high precision existing and new models of motor activity and coordination in vivo. We discovered several previously unknown features of vesicle movement, including a surprising dependence of anterograde APP vesicle movement velocity on the amount of kinesin-1. This finding is largely incompatible with the biophysical properties of kinesin-1 derived from in vitro analyses. Our data also suggest kinesin-1 and cytoplasmic dynein motors assemble in stable mixtures on APP vesicles and their direction and velocity are controlled at least in part by dynein intermediate chain.

Reis, Gerald F.; Yang, Ge; Szpankowski, Lukasz; Weaver, Carole; Shah, Sameer B.; Robinson, John T.; Hays, Thomas S.; Danuser, Gaudenz; Goldstein, Lawrence S. B.

2012-01-01

4

In vivo analysis of the overlapping functions of DnaK and trigger factor.  

PubMed

Trigger factor (TF) is a ribosome-bound protein that combines catalysis of peptidyl-prolyl isomerization and chaperone-like activities in Escherichia coli. TF was shown to cooperate with the DnaK (Hsp70) chaperone machinery in the folding of newly synthesized proteins, and the double deletion of the corresponding genes (tig and dnaK) exhibited synthetic lethality. We used a detailed genetic approach to characterize various aspects of this functional cooperation in vivo. Surprisingly, we showed that under specific growth conditions, one can delete both dnaK and tig, indicating that bacterial survival can be maintained in the absence of these two major cytosolic chaperones. The strain lacking both DnaK and TF exhibits a very narrow temperature range of growth and a high level of aggregated proteins when compared to either of the single mutants. We found that, in the absence of DnaK, both the N-terminal ribosome-binding domain and the C-terminal domain of unknown function are essential for TF chaperone activity. In contrast, the central PPIase domain is dispensable. Taken together, our data indicate that under certain conditions, folding of newly synthesized proteins in E. coli is not totally dependent on an interaction with either TF and/or DnaK, and suggest that additional chaperones may be involved in this essential process. PMID:14726952

Genevaux, Pierre; Keppel, France; Schwager, Françoise; Langendijk-Genevaux, Petra S; Hartl, F Ulrich; Georgopoulos, Costa

2004-02-01

5

Spectroscopic analysis of titanium surface functional groups under various surface modification and their behaviors in vitro and in vivo.  

PubMed

In the present study, surface functional groups of titanium surfaces gone through different treatments, including acid etched treatment (AE), nitric acid treatment (NT), heat treatment (HT), and alkali treatment (AT), and their behaviors in vitro and in vivo was thoroughly studied by spectroscopic analysis. In vitro and in vivo results revealed that the rank of bioactivity of various surfaces was AE < NT < HT < AT. XPS analysis indicated that AT greatly increased the OH group concentration on the titanium surface whereas HT reduced the OH group concentration. Thus, OH group difference could not be a good explanation of bioactivity difference. On the other hand, ToF-SIMS analysis demonstrated the TiOH+/Ti+ ratios of various surfaces correlated well with the bioactivity and the surface energies, which implied that Ti-OH could play an important role in the bioactivity. This detail investigation of the relationship between surface functional groups and surface bioactivity could help us to broaden the knowledge about the mechanism of bioactivity and to design next generation bioactive materials. PMID:17618503

Lu, Xiong; Wang, Yingbo; Yang, Xiudong; Zhang, Qiyi; Zhao, Zhanfeng; Weng, Lu-Tao; Leng, Yang

2008-02-01

6

In Vivo Noninvasive Analysis of Human Forearm Muscle Function and Fatigue: Applications to EVA Operations and Training Maneuvers  

NASA Technical Reports Server (NTRS)

Forearm muscle fatigue is one of the major limiting factors affecting endurance during performance of deep-space extravehicular activity (EVA) by crew members. Magnetic resonance (MR) provides in vivo noninvasive analysis of tissue level metabolism and fluid exchange dynamics in exercised forearm muscles through the monitoring of proton magnetic resonance imaging (MRI) and phosphorus magnetic resonance spectroscopy (P-31-MRS) parameter variations. Using a space glove box and EVA simulation protocols, we conducted a preliminary MRS/MRI study in a small group of human test subjects during submaximal exercise and recovery and following exhaustive exercise. In assessing simulated EVA-related muscle fatigue and function, this pilot study revealed substantial changes in the MR image longitudinal relaxation times (T2) as an indicator of specific muscle activation and proton flux as well as changes in spectral phosphocreatine-to-phosphate (PCr/Pi) levels as a function of tissue bioenergetic potential.

Fotedar, L. K.; Marshburn, T.; Quast, M. J.; Feeback, D. L.

1999-01-01

7

Pharmacokinetic analysis verifies P450 function during in vitro and in vivo application of a bioartificial liver.  

PubMed

Lidocaine is a sensitive substrate for evaluating liver P450 function. In this study, metabolism of lidocaine by xenogeneic hepatocytes in a hollow fiber, bioartificial liver was measured under in vitro conditions (n = 6) and in an anhepatic rabbit model. Animals in the treatment group (n = 6) received hemoperfusion by a bioartificial liver that contained 100 million rat hepatocytes. Other anhepatic rabbits received no hemoperfusion (n = 3) or a bioartificial liver with no cells (n = 3). Lidocaine clearance was 7.0 +/- 0.6 ml/min, and the half-life of lidocaine was 5.6 +/- 0.8 hr under in vitro conditions. Conversion of lidocaine to 3-hydroxy-lidocaine was confirmed in vitro and accounted for 46% of lidocaine elimination in the hepatocyte bioartificial liver. During in vivo application of the bioartificial liver, pharmacokinetic parameters of lidocaine metabolism, including drug half-life and metabolite formation, were significantly improved in anhepatic rabbits. 3-Hydroxy-lidocaine profiles verified the activity of a P450 isozyme expressed preferentially by rat hepatocytes in the bioartificial liver. We conclude that hepatic P450 activity was provided by xenogeneic hepatocytes during in vitro and in vivo applications of a bioartificial liver. PMID:8268538

Nyberg, S L; Mann, H J; Remmel, R P; Hu, W S; Cerra, F B

1993-01-01

8

Analysis of Mutant Phenotypes and Splicing Defects Demonstrates Functional Collaboration between the Large and Small Subunits of the Essential Splicing Factor U2AF In Vivo  

PubMed Central

The heterodimeric splicing factor U2AF plays an important role in 3? splice site selection, but the division of labor between the two subunits in vivo remains unclear. In vitro assays led to the proposal that the human large subunit recognizes 3? splice sites with extensive polypyrimidine tracts independently of the small subunit. We report in vivo analysis demonstrating that all five domains of spU2AFLG are essential for viability; a partial deletion of the linker region, which forms the small subunit interface, produces a severe growth defect and an aberrant morphology. A small subunit zinc-binding domain mutant confers a similar phenotype, suggesting that the heterodimer functions as a unit during splicing in Schizosaccharomyces pombe. As this is not predicted by the model for metazoan 3? splice site recognition, we sought introns for which the spU2AFLG and spU2AFSM make distinct contributions by analyzing diverse splicing events in strains harboring mutations in each partner. Requirements for the two subunits are generally parallel and, moreover, do not correlate with the length or strength of the 3? pyrimidine tract. These and other studies performed in fission yeast support a model for 3? splice site recognition in which the two subunits of U2AF functionally collaborate in vivo.

Webb, Christopher J.; Lakhe-Reddy, Sujata; Romfo, Charles M.; Wise, Jo Ann

2005-01-01

9

In Vivo Protein Binding and Functional Analysis of cis-Acting Elements in the U3 Region of the Bovine Leukemia Virus Long Terminal Repeat  

PubMed Central

Bovine leukemia virus (BLV) is a member of the human T-cell leukemia virus (HTLV)/BLV group of retroviruses. These viruses regulate their own transcription by producing Tax, a protein which activates the virus promoter region, the long terminal repeat (LTR). To explore the molecular mechanisms involved in the transactivation, we identified protein binding elements by in vivo footprinting and analyzed their function by site-?directed mutagenesis. We used in vivo dimethyl sulfate footprinting by ligation-mediated PCR to detect constitutive in vivo protein-DNA interactions in a BLV-producing cell line, Bat2Cl6. The U3 region and part of the R region of the LTR were footprinted. In addition to the cis-acting elements (three cyclic AMP-responsive elements [CREs] and two AP4 sites) reported by others to be important for Tax-mediated activation of the BLV LTR, we found footprints in regions flanking these elements and in the core promoter region. The importance of these sites for transcriptional activation was studied by site-directed mutagenesis followed by promoter function analysis of the mutants with a chloramphenicol acetyltransferase reporter system. Our data corroborate those of others showing that the CREs are necessary for transactivation of the LTR, and they identify two new functional sites not previously reported by others. We show that the middle region of the BLV U3 contains multiple dual-functioning cis-acting elements which act as either positive or negative regulatory elements depending on the cell type tested. This is the first report of a functional mapping of the cis-acting elements of a virus of the HTLV/BLV group.

Xiao, Jianqiao; Buehring, Gertrude C.

1998-01-01

10

Overcoming the heterologous bias: An in vivo functional analysis of multidrug efflux transporter, CgCdr1p in matched pair clinical isolates of Candida glabrata  

SciTech Connect

Research highlights: {yields} First report to demonstrate an in vivo expression system of an ABC multidrug transporter CgCdr1p of C. glabrata. {yields} First report on the structure and functional characterization of CgCdr1p. {yields} Functional conservation of divergent but typical residues of CgCdr1p. {yields} CgCdr1p elicits promiscuity towards substrates and has a large drug binding pocket with overlapping specificities. -- Abstract: We have taken advantage of the natural milieu of matched pair of azole sensitive (AS) and azole resistant (AR) clinical isolates of Candida glabrata for expressing its major ABC multidrug transporter, CgCdr1p for structure and functional analysis. This was accomplished by tagging a green fluorescent protein (GFP) downstream of ORF of CgCDR1 and integrating the resultant fusion protein at its native chromosomal locus in AS and AR backgrounds. The characterization confirmed that in comparison to AS isolate, CgCdr1p-GFP was over-expressed in AR isolates due to its hyperactive native promoter and the GFP tag did not affect its functionality in either construct. We observed that in addition to Rhodamine 6 G (R6G) and Fluconazole (FLC), a recently identified fluorescent substrate of multidrug transporters Nile Red (NR) could also be expelled by CgCdr1p. Competition assays with these substrates revealed the presence of overlapping multiple drug binding sites in CgCdr1p. Point mutations employing site directed mutagenesis confirmed that the role played by unique amino acid residues critical to ATP catalysis and localization of ABC drug transporter proteins are well conserved in C. glabrata as in other yeasts. This study demonstrates a first in vivo novel system where over-expression of GFP tagged MDR transporter protein can be driven by its own hyperactive promoter of AR isolates. Taken together, this in vivo system can be exploited for the structure and functional analysis of CgCdr1p and similar proteins wherein the arte-factual concerns encountered in using heterologous systems are totally excluded.

Puri, Nidhi; Manoharlal, Raman; Sharma, Monika [Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)] [Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India); Sanglard, Dominique [Institut de Microbiologie, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne (Switzerland)] [Institut de Microbiologie, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne (Switzerland); Prasad, Rajendra, E-mail: rp47jnu@gmail.com [Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)] [Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)

2011-01-07

11

First functional analysis of a novel splicing mutation in the B3GALTL gene by an ex vivo approach in Tunisian patients with typical Peters plus syndrome.  

PubMed

Peters plus syndrome is a rare recessive autosomal disorder comprising ocular anterior segment dysgenesis, short stature, hand abnormalities and distinctive facial features. It was related only to mutations in the B3GALTL gene in the 13q12.3 region. In this study, we undertook the first functional analysis of a novel c.597-2 A>G splicing mutation within the B3GALTL gene using an ex-vivo approach. The results showed a complete skipping of exon 8 in the B3GALTL cDNA, which altered the open reading frame of the mutant transcript and generated a PTC within exon 9. This finding potentially elicits the nonsense mRNA to degradation by NMD (nonsense-mediated mRNA decay). The theoretical consequences of splice site mutations, predicted with the bioinformatics tool Human Splice Finder, were investigated and evaluated in relation to ex-vivo results. The findings confirmed the key role played by the B3GALTL gene in typical Peters-plus syndromes and the utility of mRNA analysis to understand the primary impacts of this mutation and the phenotype of the disease. PMID:23954224

Ben Mahmoud, Afif; Siala, Olfa; Mansour, Riadh Ben; Driss, Fatma; Baklouti-Gargouri, Siwar; Mkaouar-Rebai, Emna; Belguith, Neila; Fakhfakh, Faiza

2013-12-10

12

Analysis of a Polycomb Group Protein Defines Regions That Link Repressive Activity on Nucleosomal Templates to In Vivo Function  

Microsoft Academic Search

Polycomb group (PcG) genes propagate patterns of transcriptional repression throughout development. The products of several such genes are part of Polycomb repressive complex 1 (PRC1), which inhibits chromatin remodeling and transcription in vitro. Genetic and biochemical studies suggest the product of the Posterior sex combs (Psc) gene plays a central role in both PcG-mediated gene repression in vivo and PRC1

Ian F. G. King; Richard B. Emmons; Nicole J. Francis; Brigitte Wild; Jurg Muller; Robert E. Kingston; Chao-ting Wu

2005-01-01

13

Targeted Gene Deletion and In Vivo Analysis of Putative Virulence Gene Function in the Pathogenic Dermatophyte Arthroderma benhamiae?  

PubMed Central

Dermatophytes cause the majority of superficial mycoses in humans and animals. However, little is known about the pathogenicity of this specialized group of filamentous fungi, for which molecular research has been limited thus far. During experimental infection of guinea pigs by the human pathogenic dermatophyte Arthroderma benhamiae, we recently detected the activation of the fungal gene encoding malate synthase AcuE, a key enzyme of the glyoxylate cycle. By the establishment of the first genetic system for A. benhamiae, specific ?acuE mutants were constructed in a wild-type strain and, in addition, in a derivative in which we inactivated the nonhomologous end-joining pathway by deletion of the A. benhamiae KU70 gene. The absence of AbenKU70 resulted in an increased frequency of the targeted insertion of linear DNA by homologous recombination, without notably altering the monitored in vitro growth abilities of the fungus or its virulence in a guinea pig infection model. Phenotypic analyses of ?acuE mutants and complemented strains depicted that malate synthase is required for the growth of A. benhamiae on lipids, major constituents of the skin. However, mutant analysis did not reveal a pathogenic role of the A. benhamiae enzyme in guinea pig dermatophytosis or during epidermal invasion of the fungus in an in vitro model of reconstituted human epidermis. The presented efficient system for targeted genetic manipulation in A. benhamiae, paired with the analyzed infection models, will advance the functional characterization of putative virulence determinants in medically important dermatophytes.

Grumbt, Maria; Defaweux, Valerie; Mignon, Bernard; Monod, Michel; Burmester, Anke; Wostemeyer, Johannes; Staib, Peter

2011-01-01

14

In vivo performance of a novel fluorinated magnetic resonance imaging agent for functional analysis of bile acid transport.  

PubMed

A novel trifluorinated cholic acid derivative, CA-lys-TFA, was designed and synthesized for use as a tool to measure bile acid transport noninvasively using magnetic resonance imaging (MRI). In the present study, the in vivo performance of CA-lys-TFA for measuring bile acid transport by MRI was investigated in mice. Gallbladder CA-lys-TFA content was quantified using MRI and liquid chromatography/tandem mass spectrometry. Results in wild-type (WT) C57BL/6J mice were compared to those in mice lacking expression of Asbt, the ileal bile acid transporter. (19)F signals emanating from the gallbladders of WT mice 7 h after oral gavage with 150 mg/kg CA-lys-TFA were reproducibly detected by MRI. Asbt-deficient mice administered the same dose had undetectable (19)F signals by MRI, and gallbladder bile CA-lys-TFA levels were 30-fold lower compared to WT animals. To our knowledge, this represents the first report of in vivo imaging of an orally absorbed drug using (19)F MRI. Fluorinated bile acid analogues have potential as tools to measure and detect abnormal bile acid transport by MRI. PMID:24708306

Vivian, Diana; Cheng, Kunrong; Khurana, Sandeep; Xu, Su; Kriel, Edwin H; Dawson, Paul A; Raufman, Jean-Pierre; Polli, James E

2014-05-01

15

Programmable nanoparticle functionalization for in vivo targeting  

PubMed Central

The emerging demand for programmable functionalization of existing base nanocarriers necessitates development of an efficient approach for cargo loading that avoids nanoparticle redesign for each individual application. Herein, we demonstrate in vivo a postformulation strategy for lipidic nanocarrier functionalization with the use of a linker peptide, which rapidly and stably integrates cargos into lipidic membranes of nanocarriers after simple mixing through a self-assembling process. We exemplified this strategy by generating a VCAM-1-targeted perfluorocarbon nanoparticle for in vivo targeting in atherosclerosis (ApoE-deficient) and breast cancer (STAT-1-deficient) models. In the atherosclerotic model, a 4.1-fold augmentation in binding to affected aortas was observed for targeted vs. nontargeted nanoparticles (P<0.0298). Likewise, in the breast cancer model, a 4.9-fold increase in the nanoparticle signal from tumor vasculature was observed for targeted vs. nontargeted nanoparticles (P<0.0216). In each case, the nanoparticle was registered with fluorine (19F) magnetic resonance spectroscopy of the nanoparticle perfluorocarbon core, yielding a quantitative estimate of the number of tissue-bound nanoparticles. Because other common nanocarriers with lipid coatings (e.g., liposomes, micelles, etc.) can employ this strategy, this peptide linker postformulation approach is applicable to more than half of the available nanosystems currently in clinical trials or clinical uses.—Pan, H., Myerson, J. W., Hu, L., Marsh, J. N., Hou K., Scott, M. J., Allen, J. S., Hu, G., San Roman, S., Lanza, G. M., Schreiber, R. D., Schlesinger, P. H., Wickline, S. A. Programmable nanoparticle functionalization for in vivo targeting.

Pan, Hua; Myerson, Jacob W.; Hu, Lingzhi; Marsh, Jon N.; Hou, Kirk; Scott, Michael J.; Allen, John S.; Hu, Grace; San Roman, Susana; Lanza, Gregory M.; Schreiber, Robert D.; Schlesinger, Paul H.; Wickline, Samuel A.

2013-01-01

16

Cyclin D1 Determines Mitochondrial Function In Vivo  

PubMed Central

The cyclin D1 gene encodes a regulatory subunit of the holoenzyme that phosphorylates and inactivates the pRb tumor suppressor to promote nuclear DNA synthesis. cyclin D1 is overexpressed in human breast cancers and is sufficient for the development of murine mammary tumors. Herein, cyclin D1 is shown to perform a novel function, inhibiting mitochondrial function and size. Mitochondrial activity was enhanced by genetic deletion or antisense or small interfering RNA to cyclin D1. Global gene expression profiling and functional analysis of mammary epithelial cell-targeted cyclin D1 antisense transgenics demonstrated that cyclin D1 inhibits mitochondrial activity and aerobic glycolysis in vivo. Reciprocal regulation of these genes was observed in cyclin D1-induced mammary tumors. Cyclin D1 thus integrates nuclear DNA synthesis and mitochondrial function.

Sakamaki, Toshiyuki; Casimiro, Mathew C.; Ju, Xiaoming; Quong, Andrew A.; Katiyar, Sanjay; Liu, Manran; Jiao, Xuanmao; Li, Anping; Zhang, Xueping; Lu, Yinan; Wang, Chenguang; Byers, Stephen; Nicholson, Robert; Link, Todd; Shemluck, Melvin; Yang, Jianguo; Fricke, Stanley T.; Novikoff, Phyllis M.; Papanikolaou, Alexandros; Arnold, Andrew; Albanese, Christopher; Pestell, Richard

2006-01-01

17

New models for analyzing mast cell functions in vivo  

PubMed Central

In addition to their well-accepted role as critical effector cells in anaphylaxis and other acute IgE-mediated allergic reactions, mast cells have been implicated in a wide variety of process that contribute to disease or help to maintain health. While some of these roles were first suggested by analyses of mast cell products or functions in vitro, it is critical to determine whether, and under which circumstances, such potential roles actually can be performed by mast cells in vivo. This review discusses recent advances in the development and analysis of mouse models to investigate the roles of mast cells and mast cell-associated products during biological responses in vivo, and comments on some of the similarities and differences in the results obtained with these newer versus older models of mast cell deficiency.

Reber, Laurent L.; Marichal, Thomas; Galli, Stephen J.

2013-01-01

18

EPR Spectroscopy of Function In Vivo  

Microsoft Academic Search

EPR can be used to study free radicals in vivo, environmental and biophysical parameters in cells and tissues, and to report metabolism, physiology, and biochemistry. The authors have attempted to judge which of these types of measurements will be productive for studies in animals and in humans. It is envisioned that a large number of in vivo applications of EPR

Harold M. Swartz; Nadeem Khan

19

In vivo analysis of cadherin function in the mouse intestinal epithelium: essential roles in adhesion, maintenance of differentiation, and regulation of programmed cell death  

PubMed Central

A model system is described for defining the physiologic functions of mammalian cadherins in vivo. 129/Sv embryonic stem (ES) cells, stably transfected with a dominant negative N-cadherin mutant (NCAD delta) under the control of a promoter that only functions in postmitotic enterocytes during their rapid, orderly, and continuous migration up small intestinal villi, were introduced into normal C57B1/6 (B6) blastocysts. In adult B6<->129/Sv chimeric mice, each villus receives the cellular output of several surrounding monoclonal crypts. A polyclonal villus located at the boundary of 129/Sv- and B6-derived intestinal epithelium contains vertical coherent bands of NCAD delta- producing enterocytes plus adjacent bands of normal B6-derived enterocytes. A comparison of the biological properties of these cell populations established that NCAD delta disrupts cell-cell and cell- matrix contacts, increases the rate of migration of enterocytes along the crypt-villus axis, results in a loss of their differentiated polarized phenotype, and produces precocious entry into a death program. These data indicate that enterocytic cadherins are critical cell survival factors that actively maintain intestinal epithelial function in vivo.

1995-01-01

20

In Vivo Imaging of Tissue Physiological Function  

Cancer.gov

The National Cancer Institute's Radiation Biology Branch is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize methods for in vivo imaging.

21

In Vivo Calcium Imaging of Neural Network Function  

NSDL National Science Digital Library

Spatiotemporal activity patterns in local neural networks are fundamental to brain function. Network activity can now be measured in vivo using two-photon imaging of cell populations that are labeled with fluorescent calcium indicators. In this review, we discuss basic aspects of in vivo calcium imaging and highlight recent developments that will help to uncover operating principles of neural circuits.

2007-12-01

22

Analysis of Chromatin Structure in Vivo  

Microsoft Academic Search

A number of important nuclear processes including replication, recombination, repair, and transcription involve the interaction of soluble nuclear proteins with DNA assembled as chromatin. Recent progress in a number of experimental systems has focused attention on the influence chromatin structure may exert on gene regulation in eukaryotes. With the advent of new technologies for the analysis of chromatin structurein vivo,studies

Joe S. Mymryk; Christy J. Fryer; Lee A. Jung; Trevor K. Archer

1997-01-01

23

Construction of an in vivo System for Functional Analysis of the Genes Involved in Sex Pheromone Production in the Silkmoth, Bombyx mori  

PubMed Central

Moths produce species-specific sex pheromones to attract conspecific mates. The biochemical processes that comprise sex pheromone biosynthesis are precisely regulated and a number of gene products are involved in this biosynthesis and regulation. In recent years, at least 300 EST clones have been isolated from Bombyx mori pheromone gland (PG) specific cDNA libraries with some of those clones [i.e., B. mori PG-specific desaturase 1 (Bmpgdesat1), PG-specific fatty acyl reductase, PG-specific acyl-CoA-binding protein, B. mori fatty acid transport protein, B. mori lipid storage droplet protein-1] characterized and demonstrated to play a role in sex pheromone production. However, most of the EST clones have yet to be fully characterized and identified. To develop an efficient system for analyzing sex pheromone production-related genes, we investigated the feasibility of a novel gene analysis system using the upstream region of Bmpgdesat1 that should contain a PG-specific gene promoter in conjunction with piggyBac vector-mediated germ line transformation. As a result, we have been able to obtain expression of our reporter gene (enhanced green fluorescent protein) in the PG but not in other tissues of transgenic B. mori. Current results indicate that we have successfully constructed a novel in vivo gene analysis system for sex pheromone production in B. mori.

Moto, Ken-Ichi; Matsumoto, Shogo

2012-01-01

24

Construction of an in vivo system for functional analysis of the genes involved in sex pheromone production in the silkmoth, Bombyx mori.  

PubMed

Moths produce species-specific sex pheromones to attract conspecific mates. The biochemical processes that comprise sex pheromone biosynthesis are precisely regulated and a number of gene products are involved in this biosynthesis and regulation. In recent years, at least 300 EST clones have been isolated from Bombyx mori pheromone gland (PG) specific cDNA libraries with some of those clones [i.e., B. mori PG-specific desaturase 1 (Bmpgdesat1), PG-specific fatty acyl reductase, PG-specific acyl-CoA-binding protein, B. mori fatty acid transport protein, B. mori lipid storage droplet protein-1] characterized and demonstrated to play a role in sex pheromone production. However, most of the EST clones have yet to be fully characterized and identified. To develop an efficient system for analyzing sex pheromone production-related genes, we investigated the feasibility of a novel gene analysis system using the upstream region of Bmpgdesat1 that should contain a PG-specific gene promoter in conjunction with piggyBac vector-mediated germ line transformation. As a result, we have been able to obtain expression of our reporter gene (enhanced green fluorescent protein) in the PG but not in other tissues of transgenic B. mori. Current results indicate that we have successfully constructed a novel in vivo gene analysis system for sex pheromone production in B. mori. PMID:22649415

Moto, Ken-Ichi; Matsumoto, Shogo

2012-01-01

25

Assessment of Glial Function in the In Vivo Retina  

PubMed Central

Glial cells, traditionally viewed as passive elements in the CNS, are now known to have many essential functions. Many of these functions have been revealed by work on retinal glial cells. This work has been conducted almost exclusively on ex vivo preparations and it is essential that retinal glial cell functions be characterized in vivo as well. To this end, we describe an in vivo rat preparation to assess the functions of retinal glial cells. The retina of anesthetized, paralyzed rats is viewed with confocal microscopy and laser speckle flowmetry to monitor glial cell responses and retinal blood flow. Retinal glial cells are labeled with the Ca2+ indicator dye Oregon Green 488 BAPTA-1 and the caged Ca2+ compound NP-EGTA by injection of the compounds into the vitreous humor. Glial cells are stimulated by photolysis of caged Ca2+ and the activation state of the cells assessed by monitoring Ca2+ indicator dye fluorescence. We find that, as in the ex vivo retina, retinal glial cells in vivo generate both spontaneous and evoked intercellular Ca2+ waves. We also find that stimulation of glial cells leads to the dilation of neighboring retinal arterioles, supporting the hypothesis that glial cells regulate blood flow in the retina. This in vivo preparation holds great promise for assessing glial cell function in the healthy and pathological retina.

Srienc, Anja I.; Kornfield, Tess E.; Mishra, Anusha; Burian, Michael A.; Newman, Eric A.

2013-01-01

26

In vivo hepatocyte MR imaging using lactose functionalized magnetoliposomes.  

PubMed

The aim of this study was to assess a novel lactose functionalized magnetoliposomes (MLs) as an MR contrast agent to target hepatocytes as well as to evaluate the targeting ability of MLs for in vivo applications. In the present work, 17 nm sized iron oxide cores functionalized with anionic MLs bearing lactose moieties were used for targeting the asialoglycoprotein receptor (ASGP-r), which is highly expressed in hepatocytes. Non-functionalized anionic MLs were tested as negative controls. The size distribution of lactose and anionic MLs was determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). After intravenous administration of both MLs, contrast enhancement in the liver was observed by magnetic resonance imaging (MRI). Label retention was monitored non-invasively by MRI and validated with Prussian blue staining and TEM for up to eight days post MLs administration. Although the MRI signal intensity did not show significant differences between functionalized and non-functionalized particles, iron-specific Prussian blue staining and TEM analysis confirmed the uptake of lactose MLs mainly in hepatocytes. In contrast, non-functionalized anionic MLs were mainly taken up by Kupffer and sinusoidal cells. Target specificity was further confirmed by high-resolution MR imaging of phantoms containing isolated hepatocytes, Kupffer cell (KCs) and hepatic stellate cells (HSCs) fractions. Hypointense signal was observed for hepatocytes isolated from animals which received lactose MLs but not from animals which received anionic MLs. These data demonstrate that galactose-functionalized MLs can be used as a hepatocyte targeting MR contrast agent to potentially aid in the diagnosis of hepatic diseases if the non-specific uptake by KCs is taken into account. PMID:24210051

Ketkar-Atre, Ashwini; Struys, Tom; Dresselaers, Tom; Hodenius, Michael; Mannaerts, Inge; Ni, Yicheng; Lambrichts, Ivo; Van Grunsven, Leo A; De Cuyper, Marcel; Himmelreich, Uwe

2014-01-01

27

Noninvasive laser-induced photoacoustic tomography for structural and functional in vivo imaging of the brain  

Microsoft Academic Search

Imaging techniques based on optical contrast analysis can be used to visualize dynamic and functional properties of the nervous system via optical signals resulting from changes in blood volume, oxygen consumption and cellular swelling associated with brain physiology and pathology. Here we report in vivo noninvasive transdermal and transcranial imaging of the structure and function of rat brains by means

Xueding Wang; Yongjiang Pang; Geng Ku; Xueyi Xie; George Stoica; Lihong V Wang

2003-01-01

28

In vivo functions of small GTPases in neocortical development.  

PubMed

Abstract The complex mammalian cortex develops from a simple neuroepithelium through the proliferation of neuronal progenitors, their asymmetric division and cell migration. Newly generated neurons transiently assume a multipolar morphology before they polarize to form a trailing axon and a leading process that is required for their radial migration. The polarization and migration events during cortical development are under the control of multiple signaling cascades that coordinate the different cellular processes involved in neuronal differentiation. GTPases perform essential functions at different stages of neuronal development as central components of these pathways. They have been widely studied using cell lines and primary neuronal cultures but their physiological function in vivo still remains to be explored in many cases. Here we review the function of GTPases that have been studied genetically by the analysis of the embryonic nervous system in knockout mice. The phenotype of these mutants has highlighted the importance of GTPases for different steps of development by orchestrating cytoskeletal rearrangements and neuronal polarization. PMID:24391191

Shah, Bhavin; Püschel, Andreas W

2014-05-01

29

Resurrection of DNA Function In Vivo from an Extinct Genome  

PubMed Central

There is a burgeoning repository of information available from ancient DNA that can be used to understand how genomes have evolved and to determine the genetic features that defined a particular species. To assess the functional consequences of changes to a genome, a variety of methods are needed to examine extinct DNA function. We isolated a transcriptional enhancer element from the genome of an extinct marsupial, the Tasmanian tiger (Thylacinus cynocephalus or thylacine), obtained from 100 year-old ethanol-fixed tissues from museum collections. We then examined the function of the enhancer in vivo. Using a transgenic approach, it was possible to resurrect DNA function in transgenic mice. The results demonstrate that the thylacine Col2A1 enhancer directed chondrocyte-specific expression in this extinct mammalian species in the same way as its orthologue does in mice. While other studies have examined extinct coding DNA function in vitro, this is the first example of the restoration of extinct non-coding DNA and examination of its function in vivo. Our method using transgenesis can be used to explore the function of regulatory and protein-coding sequences obtained from any extinct species in an in vivo model system, providing important insights into gene evolution and diversity.

Pask, Andrew J.; Behringer, Richard R.; Renfree, Marilyn B.

2008-01-01

30

Effects of Aspirin and Hypothermia on Platelet Function in Vivo.  

National Technical Information Service (NTIS)

Hypothermia, aspirin, and cardiopulmonary bypass can each induce a platelet function defect, but it is not known if the effects of aspirin and hypothermia are additive in this regard. To address this question in humans in vivo, the forearm skin temperatur...

A. D. Michelson M. R. Barnard S. F. Khuri M. J. Rohrer H. MacGregor

1997-01-01

31

Urethral function after cystectomy: a canine in vivo experiment  

Microsoft Academic Search

To study the function of the pelvic floor and the isolated urethra after removal of the bladder, 5 male and 5 female mongrel dogs were used in an acute in vivo experiment. Urethral pressure changes secondary to unilateral stimulation of the pelvic and pudendal nerves were recorded. After baseline data of the intact system were documented, the following procedures were

Wilhelm A. Hiibner; Flavio Trigo-Rocha; Eugen G. Plas; Emil A. Tanagho

1993-01-01

32

Expansion of the Clavulanic Acid Gene Cluster: Identification and In Vivo Functional Analysis of Three New Genes Required for Biosynthesis of Clavulanic Acid by Streptomyces clavuligerus  

PubMed Central

Clavulanic acid is a potent inhibitor of ?-lactamase enzymes and is of demonstrated value in the treatment of infections by ?-lactam-resistant bacteria. Previously, it was thought that eight contiguous genes within the genome of the producing strain Streptomyces clavuligerus were sufficient for clavulanic acid biosynthesis, because they allowed production of the antibiotic in a heterologous host (K. A. Aidoo, A. S. Paradkar, D. C. Alexander, and S. E. Jensen, p. 219–236, In V. P. Gullo et al., ed., Development in industrial microbiology series, 1993). In contrast, we report the identification of three new genes, orf10 (cyp), orf11 (fd), and orf12, that are required for clavulanic acid biosynthesis as indicated by gene replacement and trans-complementation analysis in S. clavuligerus. These genes are contained within a 3.4-kb DNA fragment located directly downstream of orf9 (cad) in the clavulanic acid cluster. While the orf10 (cyp) and orf11 (fd) proteins show homologies to other known CYP-150 cytochrome P-450 and [3Fe-4S] ferredoxin enzymes and may be responsible for an oxidative reaction late in the pathway, the protein encoded by orf12 shows no significant similarity to any known protein. The results of this study extend the biosynthetic gene cluster for clavulanic acid and attest to the importance of analyzing biosynthetic genes in the context of their natural host. Potential functional roles for these proteins are proposed.

Li, Rongfeng; Khaleeli, Nusrat; Townsend, Craig A.

2000-01-01

33

Functional role of TRPC proteins in vivo: lessons from TRPC-deficient mouse models  

Microsoft Academic Search

In order to elucidate the functional role of TRPC genes, in vivo, the targeted inactivation of these genes in mice is an invaluable technique. In this review, we summarize the currently available results on the phenotype of TRPC-deficient mouse lines. The analysis of mice with targeted deletion in three TRPC genes demonstrates that these proteins represent essential constituents of agonist-activated

M. Freichel; R. Vennekens; J. Olausson; M. Hoffmann; C. Müller; S. Stolz; J. Scheunemann; P. Weißgerber; V. Flockerzi

2004-01-01

34

In vivo Labeling of Constellations of Functionally Identified Neurons for Targeted in vitro Recordings  

PubMed Central

Relating the functional properties of neurons in an intact organism with their cellular and synaptic characteristics is necessary for a mechanistic understanding of brain function. However, while the functional properties of cortical neurons (e.g., tuning to sensory stimuli) are necessarily determined in vivo, detailed cellular and synaptic analysis relies on in vitro techniques. Here we describe an approach that combines in vivo calcium imaging (for functional characterization) with photo-activation of fluorescent proteins (for neuron labeling), thereby allowing targeted in vitro recording of multiple neurons with known functional properties. We expressed photo-activatable GFP rendered non-diffusible through fusion with a histone protein (H2B–PAGFP) in the mouse visual cortex to rapidly photo-label constellations of neurons in vivo at cellular and sub-cellular resolution using two-photon excitation. This photo-labeling method was compatible with two-photon calcium imaging of neuronal responses to visual stimuli, allowing us to label constellations of neurons with specific functional properties. Photo-labeled neurons were easily identified in vitro in acute brain slices and could be targeted for whole-cell recording. We also demonstrate that in vitro and in vivo image stacks of the same photo-labeled neurons could be registered to one another, allowing the exact in vivo response properties of individual neurons recorded in vitro to be known. The ability to perform in vitro recordings from neurons with known functional properties opens up exciting new possibilities for dissecting the cellular, synaptic, and circuit mechanisms that underlie neuronal function in vivo.

Lien, Anthony D.; Scanziani, Massimo

2011-01-01

35

Dendritic spines: from structure to in vivo function  

PubMed Central

Dendritic spines arise as small protrusions from the dendritic shaft of various types of neuron and receive inputs from excitatory axons. Ever since dendritic spines were first described in the nineteenth century, questions about their function have spawned many hypotheses. In this review, we introduce understanding of the structural and biochemical properties of dendritic spines with emphasis on components studied with imaging methods. We then explore advances in in vivo imaging methods that are allowing spine activity to be studied in living tissue, from super-resolution techniques to calcium imaging. Finally, we review studies on spine structure and function in vivo. These new results shed light on the development, integration properties and plasticity of spines.

Rochefort, Nathalie L; Konnerth, Arthur

2012-01-01

36

Cadmium Analysis in Vivo Kadmium-Analys in Vivo.  

National Technical Information Service (NTIS)

A method for quick selective analysis of the cadmium content in organs like kidneys and the liver with the use of neutron activation was developed. The method is based on the measurement of prompt gamma radiation emitted by the neutron absorption in the C...

R. Bergman

1980-01-01

37

In vivo quantitation of metabolites with an incomplete model function  

NASA Astrophysics Data System (ADS)

Metabolites can serve as biomarkers. Estimation of metabolite concentrations from an in vivo magnetic resonance spectroscopy (MRS) signal often uses a reference signal to estimate a model function of the spectral lineshape. When no reference signal is available, the a priori unknown in vivo lineshape must be inferred from the data at hand. This makes quantitation of metabolites from in vivo MRS signals a semi-parametric estimation problem which, in turn, implies setting of hyper-parameters by users of the software involved. Estimation of metabolite concentrations is usually done by nonlinear least-squares (NLLS) fitting of a physical model function based on minimizing the residue. In this work, the semi-parametric task is handled by complementing the usual criterion of minimal residue with a second criterion acting in tandem with it. This second criterion is derived from the general physical knowledge that the width of the line is limited. The limit on the width is a hyper-parameter; its setting appeared not critical so far. The only other hyper-parameter is the relative weight of the two criteria. But its setting too is not critical. Attendant estimation errors, obtained from a Monte Carlo calculation, show that the two-criterion NLLS approach successfully handles the semi-parametric aspect of metabolite quantitation.

Popa, E.; Capobianco, E.; de Beer, R.; van Ormondt, D.; Graveron-Demilly, D.

2009-10-01

38

In vivo analysis of Pim-1 deficiency.  

PubMed Central

The Pim-1 proto-oncogene encodes a highly conserved serine/threonine phosphokinase which is predominantly expressed in hematopoietic organs and gonads in mammals. Overexpression of Pim-1 predisposes to lymphomagenesis in mice. To develop a further understanding of Pim-1 in molecular terms, as well as in terms of its potential role in hematopoietic development, we have generated mice deficient in Pim-1 function. Pim-1-deficient mice are ostensibly normal, healthy and fertile. Detailed comparative analyses of the hematopoietic systems of the mutant mice and their wild-type littermates showed that they are indistinguishable for most of the parameters studied. Our analyses revealed one unexpected phenotype that correlated with the level of Pim-1 expression: Pim-1 deficiency correlated with a erythrocyte microcytosis, whereas overexpression of Pim-1 in E mu-Pim-1-transgenic mice resulted in erythrocyte macrocytosis. In order to confirm that the observed decrease in erythrocyte Mean Cell Volume (MCV) was attributable to the Pim-1 deficiency, we developed mice transgenic for a Pim-1 gene construct with its own promoter and showed that this transgene could restore the low erythrocyte Mean Cell Volume observed in the Pim-1-deficient mice to near wild-type levels. These results might be relevant to the observed involvement of the Pim-1 gene in mouse erythroleukemogenesis. The surprising lack of a readily observed phenotype in the lymphoid compartment of the Pim-1-deficient mice, suggests a heretofore unrecognized degree of in vivo functional redundancy of this highly conserved proto-oncogene. Images

Laird, P W; van der Lugt, N M; Clarke, A; Domen, J; Linders, K; McWhir, J; Berns, A; Hooper, M

1993-01-01

39

Cross-species functional analysis of cancer-associated fibroblasts identifies a critical role for CLCF1 and IL6 in non-small cell lung cancer in vivo  

PubMed Central

Cancer-associated fibroblasts (CAFs) have been reported to support tumor progression by a variety of mechanisms. However, their role in the progression of non-small cell lung cancer (NSCLC) remains poorly defined. In addition, the extent to which specific proteins secreted by CAFs contribute directly to tumor growth is unclear. To study the role of CAFs in NSCLC, a cross-species functional characterization of mouse and human lung CAFs was performed. CAFs supported the growth of lung cancer cells in vivo by secretion of soluble factors that directly stimulate the growth of tumor cells. Gene expression analysis comparing normal mouse lung fibroblasts (NFs) and mouse lung CAFs identified multiple genes that correlate with the CAF phenotype. A gene signature of secreted genes upregulated in CAFs was an independent marker of poor survival in NSCLC patients. This secreted gene signature was upregulated in NFs after long-term exposure to tumor cells, demonstrating that NFs are “educated” by tumor cells to acquire a CAF-like phenotype. Functional studies identified important roles for CLCF1-CNTFR and IL6-IL6R signaling, in promoting growth of NSCLC cells. This study identifies novel soluble factors contributing to the CAF protumorigenic phenotype in NSCLC and suggests new avenues for the development of therapeutic strategies.

Vicent, Silvestre; Sayles, Leanne C.; Vaka, Dedeepya; Khatri, Purvesh; Gevaert, Olivier; Chen, Ron; Zheng, Yanyan; Gillespie, Anna K.; Clarke, Nicole; Xu, Yue; Shrager, Joseph; Hoang, Chuong D.; Plevritis, Sylvia; Butte, Atul J.; Sweet-Cordero, E. Alejandro

2013-01-01

40

Cutaneous respirometry by dynamic measurement of mitochondrial oxygen tension for monitoring mitochondrial function in vivo.  

PubMed

Progress in diagnosis and treatment of mitochondrial dysfunction in chronic and acute disease could greatly benefit from techniques for monitoring of mitochondrial function in vivo. In this study we demonstrate the feasibility of in vivo respirometry in skin. Mitochondrial oxygen measurements by means of oxygen-dependent delayed fluorescence of protoporphyrin IX are shown to provide a robust basis for measurement of local oxygen disappearance rate (ODR). The fundamental principles behind the technology are described, together with an analysis method for retrievel of respirometry data. The feasibility and reproducibility of this clinically useful approach are demonstrated in a series of rats. PMID:23063685

Harms, Floor A; Voorbeijtel, Wilhelmina J; Bodmer, Sander I A; Raat, Nicolaas J H; Mik, Egbert G

2013-09-01

41

Production of a functional human acid maltase in tobacco seeds: biochemical analysis, uptake by human GSDII cells, and in vivo studies in GAA knockout mice.  

PubMed

Genetic deficiency of acid alpha glucosidase (GAA) results in glycogen storage disease type II (GSDII) or Pompe's disease. To investigate whether we could generate a functional recombinant human GAA enzyme (tobrhGAA) in tobacco seeds for future enzyme replacement therapy, we subcloned the human GAA cDNA into the plant expression plasmid-pBI101 under the control of the soybean ?-conglycinin seed-specific promoter and biochemically analyzed the tobrhGAA. Tobacco seeds contain the metabolic machinery that is more compatible with mammalian glycosylation-phosphorylation and processing. We found the tobrhGAA to be enzymatically active was readily taken up by GSDII fibroblasts and in white blood cells from whole blood to reverse the defect. The tobrhGAA corrected the enzyme defect in tissues at 7 days after a single dose following intraperitoneal (IP) administration in GAA knockout (GAA(-/-)) mice. Additionally, we could purify the tobrhGAA since it bound tightly to the matrix of Sephadex G100 and can be eluted by competition with maltose. These data demonstrate indirectly that the tobrhGAA is fully functional, predominantly proteolytically cleaved and contains the minimal phosphorylation and mannose-6-phosphate residues essential for biological activity. PMID:23907679

Martiniuk, Frank; Reggi, Serena; Tchou-Wong, Kam-Meng; Rom, William N; Busconi, Matteo; Fogher, Corrado

2013-10-01

42

Imaging visual cortical structure and function in vivo.  

PubMed

The recent advent of in vivo two-photon microscopy has allowed the repeat imaging of cortical structures at microscopic resolution within intact brains. Recent data obtained using this imaging technique shows that dendritic spines, the postsynaptic sites of the majority of excitatory synapses in the central nervous system (CNS), rapidly remodel in response to changes in the visual environment. We combined two-photon microscopy of dendritic segments with intrinsic signal imaging of visual cortical responses in the developing ferret visual cortex, and showed that when one eye was deprived during the developmental critical period for ocular dominance plasticity, both dendritic spines and visual responses to the deprived eye were rapidly altered. A brief period of recovery where the eye was re-opened resulted in a return to pre-deprivation levels for both responses and dendritic spine density, showing that structural and functional changes are linked even at very rapid timescales. Additionally, two-photon microscopy can assay other functional and structural aspects of visual cortical function which I will review. Lastly, I will compare this technique to other imaging modalities available for assessment of the visual cortex in vivo. PMID:23733120

Majewska, Ania K

2013-01-01

43

Neurovascular coupling: in vivo optical techniques for functional brain imaging  

PubMed Central

Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current applications from cutting-edge studies of cerebral neurovascular coupling functions and metabolic. Moreover, we provide a glimpse of the possible ways in which these techniques might be translated to human studies for clinical investigations of pathophysiology and disease. In vivo optical imaging techniques continue to expand and evolve, allowing us to discover fundamental basis of neurovascular coupling roles in cerebral physiology and pathophysiology.

2013-01-01

44

Identification and in vivo functional analysis by gene disruption of ctnA, an activator gene involved in citrinin biosynthesis in Monascus purpureus.  

PubMed

Citrinin, a secondary fungal metabolite of polyketide origin, is moderately nephrotoxic to vertebrates, including humans. From the red-pigment producer Monascus purpureus, a 21-kbp region flanking pksCT, which encodes citrinin polyketide synthase, was cloned. Four open reading frames (ORFs) (orf1, orf2, orf3, and orf4) in the 5'-flanking region and one ORF (orf5) in the 3'-flanking region were identified in the vicinity of pksCT. orf1 to orf5 encode a homolog of a dehydrogenase (similarity, 46%), a regulator (similarity, 38%), an oxygenase (similarity, 41%), an oxidoreductase (similarity, 26%), and a transporter (similarity, 58%), respectively. orf2 (2,006 bp with four introns) encodes a 576-amino-acid protein containing a typical Zn(II)2Cys6 DNA binding motif at the N terminus and was designated ctnA. Although reverse transcriptase PCR analysis revealed that all of these ORFs, except for orf1, were transcribed with pksCT under citrinin production conditions, the disruption of ctnA caused large decreases in the transcription of pksCT and orf5, together with reduction of citrinin production to barely detectable levels, suggesting that these two genes are under control of the ctnA product. Complementation of the ctnA disruptant with intact ctnA on an autonomously replicating plasmid restored both transcription and citrinin production, indicating that CtnA is a major activator of citrinin biosynthesis. PMID:17586673

Shimizu, Takeo; Kinoshita, Hiroshi; Nihira, Takuya

2007-08-01

45

In vivo imaging of subcutaneous structures using functional photoacoustic microscopy.  

PubMed

Functional photoacoustic microscopy (fPAM) is a hybrid technology that permits noninvasive imaging of the optical absorption contrast in subcutaneous biological tissues. fPAM uses a focused ultrasonic transducer to detect high-frequency photoacoustic (PA) signals. Volumetric images of biological tissues can be formed by two-dimensional raster scanning, and functional parameters can be further extracted from spectral measurements. fPAM is safe and applicable to animals as well as humans. This protocol provides guidelines for parameter selection, system alignment, imaging operation, laser safety and data processing for in vivo fPAM. It currently takes approximately 100 min to carry out this protocol, including approximately 50 min for data acquisition using a 10-Hz pulse-repetition-rate laser system. The data acquisition time, however, can be significantly reduced by using a laser system with a higher pulse repetition rate. PMID:17446879

Zhang, Hao F; Maslov, Konstantin; Wang, Lihong V

2007-01-01

46

Bacterial ApbC Protein Has Two Biochemical Activities That Are Required for in Vivo Function*  

PubMed Central

The ApbC protein has been shown previously to bind and rapidly transfer iron-sulfur ([Fe-S]) clusters to an apoprotein (Boyd, J. M., Pierik, A. J., Netz, D. J., Lill, R., and Downs, D. M. (2008) Biochemistry 47, 8195–8202. This study utilized both in vivo and in vitro assays to examine the function of variant ApbC proteins. The in vivo assays assessed the ability of ApbC proteins to function in pathways with low and high demand for [Fe-S] cluster proteins. Variant ApbC proteins were purified and assayed for the ability to hydrolyze ATP, bind [Fe-S] cluster, and transfer [Fe-S] cluster. This study details the first kinetic analysis of ATP hydrolysis for a member of the ParA subfamily of “deviant” Walker A proteins. Moreover, this study details the first functional analysis of mutant variants of the ever expanding family of ApbC/Nbp35 [Fe-S] cluster biosynthetic proteins. The results herein show that ApbC protein needs ATPase activity and the ability to bind and rapidly transfer [Fe-S] clusters for in vivo function.

Boyd, Jeffrey M.; Sondelski, Jamie L.; Downs, Diana M.

2009-01-01

47

In vivo minimally invasive interstitial multi-functional microendoscopy  

PubMed Central

Developing minimally invasive methodologies for imaging of internal organs is an emerging field in the biomedical examination research. This paper introduces a new multi-functional microendoscope device capable of imaging of internal organs with a minimal invasive intervention. In addition, the developed microendoscope can also be employed as a monitoring device for measuring local hemoglobin concentration in blood stream when administrated into a blood artery. The microendoscope device has a total external diameter of only 200??m and can provide high imaging resolution capability of more than 5,000 pixels. The device can detect features with a spatial resolution of less than 1??m. The microendoscope has been tested both in-vitro as well as in-vivo in rats presenting a promising and powerful tool as a high resolution and minimally invasive imaging facility suitable for previously unreachable clinical modalities.

Shahmoon, Asaf; Aharon, Shiran; Kruchik, Oded; Hohmann, Martin; Slovin, Hamutal; Douplik, Alexandre; Zalevsky, Zeev

2013-01-01

48

In vivo function of surfactants containing phosphatidylcholine analogs.  

PubMed

Increased phospholipase A2 activity demonstrated in some forms of lung injury may contribute to surfactant dysfunction. Phospholipase A2-resistant analogs of dipalmitoylphosphatidylcholine (DPPC) with surfactant properties might therefore be useful lipid components of treatment surfactants for certain lung injuries. The in vivo function of surfactants containing DPPC or the phospholipase-resistant analogs dihexadecylphosphatidylcholine (DEPC) or dihexadecylphosphonotidylcholine (DEPnC), with or without surfactant proteins B and C (SP-B+C), was thus evaluated in preterm rabbits (27 days' gestation). Rabbits randomly received one of seven surfactants (DPPC, DEPC, DEPnC, DPPC+SP-B+C, DEPC+SP-B+C, DEPnC+SP-B+C, or lipid extract surfactant [LES]) or 0.45% NaCl (control) and were ventilated for 30 min. Lipid-only surfactants decreased ventilatory pressures (peak inspiratory pressures minus positive end-expiratory pressure) relative to control (p < 0.05). Addition of SP-B+C further decreased ventilatory pressures to levels similar to LES (p < 0.01 versus control, lipid-only surfactants). Lung dynamic compliances and postventilation pressure-volume curves improved in the following order: LES, SP-B+C lipid surfactants > lipid-only surfactants > control (p < 0.05). All surfactant preparations decreased intravascular 125I-albumin recoveries in the lungs relative to control (p < 0.01 for all surfactants versus control). These results indicate that DEPC and DEPnC were as effective as DPPC as lipid components of synthetic surfactants. And like DPPC, the analogs interacted with isolated SP-B+C and improved in vivo function to levels comparable to LES. PMID:7921463

Dizon-Co, L; Ikegami, M; Ueda, T; Jobe, A H; Lin, W H; Turcotte, J G; Notter, R H; Rider, E D

1994-10-01

49

Functional importance of BAK1 tyrosine phosphorylation in vivo  

PubMed Central

The plant receptor kinase BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1) is known as a partner of several ligand-binding leucine-rich repeat receptor kinases, including BRASSINOSTEROID INSENSITIVE 1 (BRI1) and the flagellin receptor FLS2. Autophosphorylation of receptor kinases is recognized to be an important process in receptor kinase signaling, and at least with the recombinant protein, BAK1 was shown to autophosphorylate on Tyr residues1 in addition to numerous Ser/Thr residues documented previously in reference 2. We recently identified Tyr-610 in the carboxy-terminal domain of BAK1 as a major site of autophosphorylation and showed that phosphorylation of this residue is essential for at least some functions of BAK1 in vivo.3 In particular, the function of BAK1 as co-receptor with BRI1 in brassinosteroid (BR) signaling is impaired in transgenic plants expressing the BAK1(Y610F)-Flag directed mutant. Recombinant cytoplasmic domains of BRI1 and BAK1 interact and transphosphorylate each other in vitro in a manner that mimics their interaction in vivo; while BAK1(Y610F) binds normally to BRI1 its ability to transphosphorylate and activate the kinase domain of BRI1 is severely compromised. To further elaborate on this earlier model, we present additional results showing that the interaction between BAK1 and BRI1 in vitro is Mg2+ dependent, suggesting that cytosolic [Mg2+] may play some role in receptor kinase signaling in vivo. We also compare the primary structures of BRI1 and BAK1 in terms of the occurrence of Tyr residues in the cytoplasmic domain, and identify differences in which residues are essential for kinase activity. Finally, transgenic plants expressing the BAK1(Y610F) directed mutant have alterations in the transcriptome that extend beyond the genes that are BR regulated in nontransgenic plants. In particular, the basal expression of many defense genes is significantly reduced in Y610F plants, which is consistent with the earlier report in reference 4, that BAK1 controls the expression of a number of genes associated with microbial infection. The present results establish a site-specific role for Tyr phosphorylation of BAK1 in BR signaling and regulation of plant defense mechanisms, which may have implications for enhancing agricultural productivity.

Oh, Man-Ho; Wu, Xia; Clouse, Steven D

2011-01-01

50

Functional imaging: monitoring heme oxygenase-1 gene expression in vivo  

NASA Astrophysics Data System (ADS)

The regulation of genetic elements can be monitored in living animals using photoproteins as reporters. Heme oxygenase (HO) is the key catabolic enzyme in the heme degradation pathway. Here, HO expression serves as a model for in vivo functional imaging of transcriptional regulation of a clinically relevant gene. HO enzymatic activity is inhibited by heme analogs, metalloporphyrins, but many members of this family of compounds also activate transcription of the HO-1 promoter. The degree of transcriptional activation by twelve metalloporphyrins, differing at the central metal and porphyrin ring substituents, was evaluated in both NIH 3T3 stable lines and transgenic animals containing HO-1 promoter-luciferase gene fusions. In the correlative cell culture assays, the metalloporphyrins increased transcription form the full length HO promoter fusion to varying degrees, but none increased transcription from a truncated HO-1 promoter. These results suggested that one or both of the two distal enhancer elements located at -4 and -10 Kb upstream from transcriptional start are required for HO-1 induction by heme and its analogs. The full-length HO-1-luc fusion was then evaluated as a transgene in mice. It was possible to monitor the effects of the metalloporphyrins, SnMP and ZnPP, in living animals over time. This spatiotemporal analyses of gene expression in vivo implied that alterations in porphyrin ring substituents and the central metal may affect the extent of gene activation. These data further indicate that using photoprotein reporters, subtle differences in gene expression can be monitored in living animals.

Zhang, Weisheng; Reilly-Contag, Pamela; Stevenson, David K.; Contag, Christopher H.

1999-07-01

51

DHA-enriched fish oil targets B cell lipid microdomains and enhances ex vivo and in vivo B cell function  

PubMed Central

DHA is a n-3 LCPUFA in fish oil that generally suppresses T lymphocyte function. However, the effect of fish oil on B cell function remains relatively understudied. Given the important role of B cells in gut immunity and increasing human fish oil supplementation, we sought to determine whether DFO leads to enhanced B cell activation in the SMAD?/? colitis-prone mouse model, similar to that observed with C57BL/6 mice. This study tested the hypothesis that DHA from fish oil is incorporated into the B cell membrane to alter lipid microdomain clustering and enhance B cell function. Purified, splenic B cells from DFO-fed mice displayed increased DHA levels and diminished GM1 microdomain clustering. DFO enhanced LPS-induced B cell secretion of IL-6 and TNF-? and increased CD40 expression ex vivo compared with CON. Despite increased MHCII expression in the unstimulated ex vivo B cells from DFO-fed mice, we observed no difference in ex vivo OVA-FITC uptake in B cells from DFO or CON mice. In vivo, DFO increased lymphoid tissue B cell populations and surface markers of activation compared with CON. Finally, we investigated whether these ex vivo and in vivo observations were consistent with systemic changes. Indeed, DFO-fed mice had significantly higher plasma IL-5, IL-13, and IL-9 (Th2-biasing cytokines) and cecal IgA compared with CON. These results support the hypothesis and an emerging concept that fish oil enhances B cell function in vivo.

Gurzell, Eric A.; Teague, Heather; Harris, Mitchel; Clinthorne, Jonathan; Shaikh, Saame Raza; Fenton, Jenifer I.

2013-01-01

52

DHA-enriched fish oil targets B cell lipid microdomains and enhances ex vivo and in vivo B cell function.  

PubMed

DHA is a n-3 LCPUFA in fish oil that generally suppresses T lymphocyte function. However, the effect of fish oil on B cell function remains relatively understudied. Given the important role of B cells in gut immunity and increasing human fish oil supplementation, we sought to determine whether DFO leads to enhanced B cell activation in the SMAD-/- colitis-prone mouse model, similar to that observed with C57BL/6 mice. This study tested the hypothesis that DHA from fish oil is incorporated into the B cell membrane to alter lipid microdomain clustering and enhance B cell function. Purified, splenic B cells from DFO-fed mice displayed increased DHA levels and diminished GM1 microdomain clustering. DFO enhanced LPS-induced B cell secretion of IL-6 and TNF-? and increased CD40 expression ex vivo compared with CON. Despite increased MHCII expression in the unstimulated ex vivo B cells from DFO-fed mice, we observed no difference in ex vivo OVA-FITC uptake in B cells from DFO or CON mice. In vivo, DFO increased lymphoid tissue B cell populations and surface markers of activation compared with CON. Finally, we investigated whether these ex vivo and in vivo observations were consistent with systemic changes. Indeed, DFO-fed mice had significantly higher plasma IL-5, IL-13, and IL-9 (Th2-biasing cytokines) and cecal IgA compared with CON. These results support the hypothesis and an emerging concept that fish oil enhances B cell function in vivo. PMID:23180828

Gurzell, Eric A; Teague, Heather; Harris, Mitchel; Clinthorne, Jonathan; Shaikh, Saame Raza; Fenton, Jenifer I

2013-04-01

53

In-vivo imaging of the photoreceptor mosaic in retinal dystrophies and correlations with visual function  

SciTech Connect

To relate in-vivo microscopic retinal changes to visual function assessed with clinical tests in patients with various forms of retinal dystrophies. The UC Davis Adaptive Optics (AO) Fundus Camera was used to acquire in-vivo retinal images at the cellular level. Visual function tests, consisting of visual field analysis, multifocal electroretinography (mfERG), contrast sensitivity and color vision measures, were performed on all subjects. Five patients with different forms of retinal dystrophies and three control subjects were recruited. Cone densities were quantified for all retinal images. In all images of diseased retinas, there were extensive areas of dark space between groups of photoreceptors, where no cone photoreceptors were evident. These irregular features were not seen in healthy retinas, but were characteristic features in fundi with retinal dystrophies. There was a correlation between functional vision loss and the extent to which the irregularities occurred in retinal images. Cone densities were found to decrease with an associated decrease in retinal function. AO fundus photography is a reliable technique for assessing and quantifying the changes in the photoreceptor layer as disease progresses. Furthermore, this technique can be useful in cases where visual function tests give borderline or ambiguous results, as it allows visualization of individual photoreceptors.

Choi, S; Doble, N; Hardy, J; Jones, S; Keltner, J; Olivier, S; Werner, J S

2005-10-26

54

Vivo-Morpholino knockdown of ?IIb: A novel approach to inhibit thrombocyte function in adult zebrafish  

PubMed Central

SUMMARY Knockdown of protein function by antisense oligonucleotides has been used to understand the protein function not only in development but also in human diseases. Recently, Vivo-Morpholinos, chemically modified morpholinos which penetrate the cells, have been used in adult experimental animal models to alter the splicing and thereby change the protein expression. Until now, there have been no such studies using Vivo-Morpholinos, to evaluate hemostatic function in adult animals. We injected ?IIb Vivo-Morpholinos intravenously into adult zebrafish. Thrombocyte function was assayed by time to aggregation assay of the citrated blood, annexin V binding to thrombocytes, and gill bleeding. The thrombocyte functional inhibition occurred in 24 hrs after ?IIb Vivo-Morpholinos injection and reached a maximum in 48 hrs. However, in 72 hrs, the inhibition was no longer observed. Reduction of annexin V binding to thrombocytes and increased gill bleeding were observed 48 hrs after ?IIb Vivo-Morpholino injections. The action of the ?IIb Vivo-Morpholino was demonstrated by the presence of an alternatively spliced ?IIb mRNA and the reduction of ?IIb in thrombocytes of fish treated with ?IIb Vivo-Morpholino. These results provide the first proof of principle that thrombocyte function can be inhibited by thrombocyte-specific Vivo-Morpholinos in adult zebrafish and presents an approach to knockdown thrombocyte-specific genes to conduct biochemical studies in thrombocytes. This study also provides the first antisense antithrombotic approach to inhibit thrombocyte function in adult zebrafish.

Kim, Seongcheol; Radhakrishnan, Uvaraj P; Rajpurohit, Surendra Kumar; Kulkarni, Vrinda; Jagadeeswaran, Pudur

2010-01-01

55

A novel approach to in vivo mitral valve stress analysis  

PubMed Central

Three-dimensional (3-D) echocardiography allows the generation of anatomically correct and time-resolved geometric mitral valve (MV) models. However, as imaged in vivo, the MV assumes its systolic geometric configuration only when loaded. Customarily, finite element analysis (FEA) is used to predict material stress and strain fields rendered by applying a load on an initially unloaded model. Therefore, this study endeavors to provide a framework for the application of in vivo MV geometry and FEA to MV physiology, pathophysiology, and surgical repair. We hypothesize that in vivo MV geometry can be reasonably used as a surrogate for the unloaded valve in computational (FEA) simulations, yielding reasonable and meaningful stress and strain magnitudes and distributions. Three experiments were undertaken to demonstrate that the MV leaflets are relatively nondeformed during systolic loading: 1) leaflet strain in vivo was measured using sonomicrometry in an ovine model, 2) hybrid models of normal human MVs as constructed using transesophageal real-time 3-D echocardiography (rt-3DE) were repeatedly loaded using FEA, and 3) serial rt-3DE images of normal human MVs were used to construct models at end diastole and end isovolumic contraction to detect any deformation during isovolumic contraction. The average linear strain associated with isovolumic contraction was 0.02 ± 0.01, measured in vivo with sonomicrometry. Repeated loading of the hybrid normal human MV demonstrated little change in stress or geometry: peak von Mises stress changed by <4% at all locations on the anterior and posterior leaflets. Finally, the in vivo human MV deformed minimally during isovolumic contraction, as measured by the mean absolute difference calculated over the surfaces of both leaflets between serial MV models: 0.53 ± 0.19 mm. FEA modeling of MV models derived from in vivo high-resolution truly 3-D imaging is reasonable and useful for stress prediction in MV pathologies and repairs.

Xu, Chun; Brinster, Clay J.; Jassar, Arminder S.; Vergnat, Mathieu; Eperjesi, Thomas J.; Gorman, Robert C.; Gorman, Joseph H.

2010-01-01

56

Functional Analysis in Behavioral Medicine  

Microsoft Academic Search

Behavior therapists must often design treatments for individual patients who present with a wide array of psychophysiological disorders and health problems. The functional analysis and functional analytic causal modeling is a learning-based, empirically focused assessment technique used to systematically gather, integrate, and summarize information about the form and function of a patient’s symptoms. A functional analytic case model can be

William H. O’Brien; Victoria Carhart

2011-01-01

57

Identification of in vivo phosphorylation sites and their functional significance in the sodium iodide symporter.  

PubMed

The Na+/I- symporter (NIS)-mediated iodide uptake activity is the basis for targeted radioiodide ablation of thyroid cancers. Although it has been shown that NIS protein is phosphorylated, neither the in vivo phosphorylation sites nor their functional significance has been reported. In this study, Ser-43, Thr-49, Ser-227, Thr-577, and Ser-581 were identified as in vivo NIS phosphorylation sites by mass spectrometry. Kinetic analysis of NIS mutants of the corresponding phosphorylated amino acid residue indicated that the velocity of iodide transport of NIS is modulated by the phosphorylation status of Ser-43 and Ser-581. We also found that the phosphorylation status of Thr-577 may be important for NIS protein stability and that the phosphorylation status of Ser-227 is functionally silent. Thr-49 appears to be critical for proper local structure/conformation of NIS because mutation of Thr-49 to alanine, aspartic acid, or serine results in reduced NIS activity without alterations in total or cell surface NIS protein levels. Taken together, we showed that NIS protein levels and functional activity could be modulated by phosphorylation through distinct mechanisms. PMID:17913707

Vadysirisack, Douangsone D; Chen, Eric S-W; Zhang, Zhaoxia; Tsai, Ming-Daw; Chang, Geen-Dong; Jhiang, Sissy M

2007-12-21

58

In vivo function of the craniofacial haft: the interorbital "pillar".  

PubMed

The craniofacial haft resists forces generated in the face during feeding, but the importance of these forces for the form of the craniofacial haft remains to be determined. In vivo bone strain data were recorded from the medial orbital wall in an owl monkey (Aotus), rhesus macaques (Macaca mulatta), and a galago (Otolemur) during feeding. These data were used to determine whether: the interorbital region can be modeled as a simple beam under bending or shear; the face is twisting on the brain case during unilateral biting or mastication; the interorbital "pillar" is being axially compressed during incisor loading and both axially compressed and laterally bent during mastication; and the interorbital "pillar" transmits axial compressive forces from the toothrow to the braincase. The strain data reveal that the interorbital region cannot be modeled as a anteroposteriorly oriented beam bent superiorly in the sagittal plane during incision or mastication. The strain orientations recorded in the majority of experiments are concordant with those predicted for a short beam under shear, although the anthropoids displayed evidence of multiple loading regimes in the medial orbital wall. Strain orientation data corroborate the hypothesis that the strepsirrhine face is twisted during mastication. The hypothesis that the interorbital region is a member in a rigid frame subjected to axial compression during mastication receives some support. The hypothesis that the interorbital region is a member in a rigid frame subjected to lateral bending during mastication is supported by the epsilon1/absolute value epsilon2 ratio data but not by the strain orientation data. The timing of peak shear strains in the medial orbital wall of anthropoids does not bear a consistent relationship to the timing of peak shear strain in the mandibular corpus, suggesting that bite force is not the only external force influencing the medial orbital wall. Strain orientation data suggest the existence of two distinct loading regimes, possibly associated with masseter or medial pterygoid contraction. Regardless of the loading regime, all taxa showed low strain magnitudes in the medial orbital wall relative to the anterior root of the zygoma and the mandibular corpus. The strain gradients documented here and elsewhere suggest that, in anthropoids at least, local effects of external forces are more important than a single global loading regime. The low strain magnitudes in the medial orbital wall and in other thin bony plates around the orbit suggest that these structures are not optimally designed for resisting feeding forces. It is hypothesized that their function is to provide rigid support and protection for soft-tissue structures such as the nasal epithelium, the brain, meninges, and the eye and its adnexa. In contrast with the face of Otolemur, which appears to be subjected to a single predominant loading regime, anthropoids may experience different loading regimes in different parts of the face. This implies that the anthropoid and strepsirrhine facial skulls might be optimized for different functions. PMID:11590585

Ross, C F

2001-10-01

59

Dissection of Pol II Trigger Loop Function and Pol II Activity-Dependent Control of Start Site Selection In Vivo  

PubMed Central

Structural and biochemical studies have revealed the importance of a conserved, mobile domain of RNA Polymerase II (Pol II), the Trigger Loop (TL), in substrate selection and catalysis. The relative contributions of different residues within the TL to Pol II function and how Pol II activity defects correlate with gene expression alteration in vivo are unknown. Using Saccharomyces cerevisiae Pol II as a model, we uncover complex genetic relationships between mutated TL residues by combinatorial analysis of multiply substituted TL variants. We show that in vitro biochemical activity is highly predictive of in vivo transcription phenotypes, suggesting direct relationships between phenotypes and Pol II activity. Interestingly, while multiple TL residues function together to promote proper transcription, individual residues can be separated into distinct functional classes likely relevant to the TL mechanism. In vivo, Pol II activity defects disrupt regulation of the GTP-sensitive IMD2 gene, explaining sensitivities to GTP-production inhibitors, but contrasting with commonly cited models for this sensitivity in the literature. Our data provide support for an existing model whereby Pol II transcriptional activity provides a proxy for direct sensing of NTP levels in vivo leading to IMD2 activation. Finally, we connect Pol II activity to transcription start site selection in vivo, implicating the Pol II active site and transcription itself as a driver for start site scanning, contravening current models for this process.

Kaplan, Craig D.; Jin, Huiyan; Zhang, Ivan Liang; Belyanin, Andrey

2012-01-01

60

Functional Group Analysis.  

ERIC Educational Resources Information Center

Literature on analytical methods related to the functional groups of 17 chemical compounds is reviewed. These compounds include acids, acid azides, alcohols, aldehydes, ketones, amino acids, aromatic hydrocarbons, carbodiimides, carbohydrates, ethers, nitro compounds, nitrosamines, organometallic compounds, peroxides, phenols, silicon compounds,…

Smith, Walter T., Jr.; Patterson, John M.

1984-01-01

61

In Vivo Application of Optogenetics for Neural Circuit Analysis  

PubMed Central

Optogenetics combines optical and genetic methods to rapidly and reversibly control neural activities or other cellular functions. Using genetic methods, specific cells or anatomical pathways can be sensitized to light through exogenous expression of microbial light activated opsin proteins. Using optical methods, opsin expressing cells can be rapidly and reversibly controlled by pulses of light of specific wavelength. With the high spatial temporal precision, optogenetic tools have enabled new ways to probe the causal role of specific cells in neural computation and behavior. Here, we overview the current state of the technology, and provide a brief introduction to the practical considerations in applying optogenetics in vivo to analyze neural circuit functions.

2012-01-01

62

Continuous blood glucose analysis in vitro and in vivo  

Microsoft Academic Search

Summary  A practical method for continuous blood glucose analysis in vivo is described. Using an interference-free enzyme reagent in\\u000a a modified Auto-Analyzer whole blood glucose concentration can be monitored continuously and interpreted in terms of the actual\\u000a plasma glucose concentration. The method uses a novel technique for preheating the sample diluent without introducing additional\\u000a time delays, consumes whole blood at a

A. M. Albisser; J. Ellman; A. Hanna; Y. Goriya; H. Minuk

1978-01-01

63

Structure and in vivo function of Hsp90  

Microsoft Academic Search

Until recently, Hsp90 was one of the least well understood of the molecular chaperones, but considerable progress is now being made in unravelling its biochemistry. Hsp90 has now been shown to possess an inherent ATPase that is essential for the activation of authentic ‘client’ proteins in vivo and in vitro. The molecular detail of Hsp90’s interactions with co-chaperones is also

Laurence H Pearl; Chrisostomos Prodromou

2000-01-01

64

Diesel exhaust particulate induces pulmonary and systemic inflammation in rats without impairing endothelial function ex vivo or in vivo  

PubMed Central

Background Inhalation of diesel exhaust impairs vascular function in man, by a mechanism that has yet to be fully established. We hypothesised that pulmonary exposure to diesel exhaust particles (DEP) would cause endothelial dysfunction in rats as a consequence of pulmonary and systemic inflammation. Methods Wistar rats were exposed to DEP (0.5 mg) or saline vehicle by intratracheal instillation and hind-limb blood flow, blood pressure and heart rate were monitored in situ 6 or 24 h after exposure. Vascular function was tested by administration of the endothelium-dependent vasodilator acetylcholine (ACh) and the endothelium-independent vasodilator sodium nitroprusside (SNP) in vivo and ex vivo in isolated rings of thoracic aorta, femoral and mesenteric artery from DEP exposed rats. Bronchoalveolar lavage fluid (BALF) and blood plasma were collected to assess pulmonary (cell differentials, protein levels & interleukin-6 (IL-6)) and systemic (IL-6), tumour necrosis factor alpha (TNF?) and C-reactive protein (CRP)) inflammation, respectively. Results DEP instillation increased cell counts, total protein and IL-6 in BALF 6 h after exposure, while levels of IL-6 and TNF? were only raised in blood 24 h after DEP exposure. DEP had no effect on the increased hind-limb blood flow induced by ACh in vivo at 6 or 24 h. However, responses to SNP were impaired at both time points. In contrast, ex vivo responses to ACh and SNP were unaltered in arteries isolated from rats exposed to DEP. Conclusions Exposure of rats to DEP induces both pulmonary and systemic inflammation, but does not modify endothelium-dependent vasodilatation. Other mechanisms in vivo limit dilator responses to SNP and these require further investigation.

2012-01-01

65

Function Analysis and Decomposistion using Function Analysis Systems Technique  

SciTech Connect

The "Father of Value Analysis", Lawrence D. Miles, was a design engineer for General Electric in Schenectady, New York. Miles developed the concept of function analysis to address difficulties in satisfying the requirements to fill shortages of high demand manufactured parts and electrical components during World War II. His concept of function analysis was further developed in the 1960s by Charles W. Bytheway, a design engineer at Sperry Univac in Salt Lake City, Utah. Charles Bytheway extended Mile's function analysis concepts and introduced the methodology called Function Analysis Systems Technique (FAST) to the Society of American Value Engineers (SAVE) at their International Convention in 1965 (Bytheway 1965). FAST uses intuitive logic to decompose a high level, or objective function into secondary and lower level functions that are displayed in a logic diagram called a FAST model. Other techniques can then be applied to allocate functions to components, individuals, processes, or other entities that accomplish the functions. FAST is best applied in a team setting and proves to be an effective methodology for functional decomposition, allocation, and alternative development.

Wixson, James Robert

1999-06-01

66

Function Analysis and Decomposistion using Function Analysis Systems Technique  

SciTech Connect

The "Father of Value Analysis", Lawrence D. Miles, was a design engineer for General Electric in Schenectady, New York. Miles developed the concept of function analysis to address difficulties in satisfying the requirements to fill shortages of high demand manufactured parts and electrical components during World War II. His concept of function analysis was further developed in the 1960s by Charles W. Bytheway, a design engineer at Sperry Univac in Salt Lake City, Utah. Charles Bytheway extended Mile's function analysis concepts and introduced the methodology called Function Analysis Systems Techniques (FAST) to the Society of American Value Engineers (SAVE) at their International Convention in 1965 (Bytheway 1965). FAST uses intuitive logic to decompose a high level, or objective function into secondary and lower level functions that are displayed in a logic diagram called a FAST model. Other techniques can then be applied to allocate functions to components, individuals, processes, or other entities that accomplish the functions. FAST is best applied in a team setting and proves to be an effective methodology for functional decomposition, allocation, and alternative development.

J. R. Wixson

1999-06-01

67

In vitro gene regulatory networks predict in vivo function of liver  

PubMed Central

Background Evolution of toxicity testing is predicated upon using in vitro cell based systems to rapidly screen and predict how a chemical might cause toxicity to an organ in vivo. However, the degree to which we can extend in vitro results to in vivo activity and possible mechanisms of action remains to be fully addressed. Results Here we use the nitroaromatic 2,4,6-trinitrotoluene (TNT) as a model chemical to compare and determine how we might extrapolate from in vitro data to in vivo effects. We found 341 transcripts differentially expressed in common among in vitro and in vivo assays in response to TNT. The major functional term corresponding to these transcripts was cell cycle. Similarly modulated common pathways were identified between in vitro and in vivo. Furthermore, we uncovered the conserved common transcriptional gene regulatory networks between in vitro and in vivo cellular liver systems that responded to TNT exposure, which mainly contain 2 subnetwork modules: PTTG1 and PIR centered networks. Interestingly, all 7 genes in the PTTG1 module were involved in cell cycle and downregulated by TNT both in vitro and in vivo. Conclusions The results of our investigation of TNT effects on gene expression in liver suggest that gene regulatory networks obtained from an in vitro system can predict in vivo function and mechanisms. Inhibiting PTTG1 and its targeted cell cyle related genes could be key machanism for TNT induced liver toxicity.

2010-01-01

68

In Vivo Function of the ER-Golgi Transport Protein LMAN1 in Photoreceptor Homeostasis.  

PubMed

LMAN1 is a type I transmembrane protein that selectively transports its cargo proteins from ER to ER-Golgi intermediate compartment (ERGIC) and Golgi. Lman1 is a direct target of the transcription factor NRL in mouse retina. Therefore, we examined the in vivo function of LMAN1 in retina. Although Lman1 (- / -) mouse eyes did not show abnormality in histology and electroretinogram analysis at 3 months, Lman1 (- / -) retina at 6 months showed a decrease in cis-Golgi markers GM130 and GRASP65. We also observed abnormal level and location of Rhodopsin in these mice. Taken together, LMAN1 may play a role in photoreceptor gene transport and homeostasis. PMID:24664723

Hao, Hong; Gregorski, Janina; Qian, Haohua; Li, Yichao; Gao, Chun Y; Idrees, Sana; Zhang, Bin

2014-01-01

69

Mapping 3-D functional capillary geometry in rat skeletal muscle in vivo  

PubMed Central

We have developed a novel mapping software package to reconstruct microvascular networks in three dimensions (3-D) from in vivo video images for use in blood flow and O2 transport modeling. An intravital optical imaging system was used to collect video sequences of blood flow in microvessels at different depths in the tissue. Functional images of vessels were produced from the video sequences and were processed using automated edge tracking software to yield location and geometry data for construction of the 3-D network. The same video sequences were analyzed for hemodynamic and O2 saturation data from individual capillaries in the network. Simple user-driven commands allowed the connection of vessel segments at bifurcations, and semiautomated registration enabled the tracking of vessels across multiple focal planes and fields of view. The reconstructed networks can be rotated and manipulated in 3-D to verify vessel connections and continuity. Hemodynamic and O2 saturation measurements made in vivo can be indexed to corresponding vessels and visualized using colorized maps of the vascular geometry. Vessels in each reconstruction are saved as text-based files that can be easily imported into flow or O2 transport models with complete geometry, hemodynamic, and O2 transport conditions. The results of digital morphometric analysis of seven microvascular networks showed mean capillary diameters and overall capillary density consistent with previous findings using histology and corrosion cast techniques. The described mapping software is a valuable tool for the quantification of in vivo microvascular geometry, hemodynamics, and oxygenation, thus providing rich data sets for experiment-based computational models.

Milkovich, Stephanie; Goldman, Daniel; Ellis, Christopher G.

2012-01-01

70

Behavior of Endogenous Tumor-Associated Macrophages Assessed In Vivo Using a Functionalized Nanoparticle12  

PubMed Central

Tumor-associated macrophages (TAMs) invade the tumor stroma in many cancers, yet their role is incompletely understood. To visualize and better understand these critical cells in tumor progression, we screened a portfolio of rationally selected, injectable agents to image endogenous TAMs ubiquitously in three different cancer models (colon carcinoma, lung adenocarcinoma, and soft tissue sarcoma). AMTA680, a functionally derivatized magneto-fluorescent nanoparticle, labeled a subset of myeloid cells with an “M2” macrophage phenotype, whereas other neighboring cells, including tumor cells and a variety of other leukocytes, remained unlabeled. We further show that AMTA680-labeled endogenous TAMs are not altered and can be tracked noninvasively at different resolutions and using various imaging modalities, e.g., fluorescence molecular tomography, magnetic resonance imaging, and multiphoton and confocal intravital microscopy. Quantitative assessment of TAM distribution and activity in vivo identified that these cells cluster in delimited foci within tumors, show relatively low motility, and extend cytoplasmic protrusions for prolonged physical interactions with neighboring tumor cells. Noninvasive imaging can also be used to monitor TAM-depleting regimen quantitatively. Thus, AMTA680 or related cell-targeting agents represent appropriate injectable vehicles for in vivo analysis of the tumor microenvironment.

Leimgruber, Antoine; Berger, Cedric; Cortez-Retamozo, Virna; Etzrodt, Martin; Newton, Andita P; Waterman, Peter; Figueiredo, Jose Luiz; Kohler, Rainer H; Elpek, Natalie; Mempel, Thorsten R; Swirski, Filip K; Nahrendorf, Matthias; Weissleder, Ralph; Pittet, Mikael J

2009-01-01

71

Recent developments in in vivo neutron activation analysis facilities.  

PubMed

Two new facilities for in vivo activation analysis of patients have been designed, developed, and constructed at Toronto General Hospital. One of these is for the determination of body calcium for the diagnosis of osteoporosis and other diseases associated with bone loss. The other is for the measurement of total body nitrogen for the determination of protein status. These facilities replace old university facilities and take into account the comfort and management of patients. In addition, in the case of the calcium facility, the precision of the measurements has been improved because of larger detector volume and increased neutron source strength. Both the facilities are now in routine hospital clinical use. PMID:1704745

Krishnan, S S; McNeill, K G; Mernagh, J R; Harrison, J E

1990-01-01

72

Analysis of the mutations induced by conazole fungicides in vivo.  

PubMed

The mouse liver tumorigenic conazole fungicides triadimefon and propiconazole have previously been shown to be in vivo mouse liver mutagens in the Big Blue transgenic mutation assay when administered in feed at tumorigenic doses, whereas the non-tumorigenic conazole myclobutanil was not mutagenic. DNA sequencing of the mutants recovered from each treatment group as well as from animals receiving control diet was conducted to gain additional insight into the mode of action by which tumorigenic conazoles induce mutations. Relative dinucleotide mutabilities (RDMs) were calculated for each possible dinucleotide in each treatment group and then examined by multivariate statistical analysis techniques. Unsupervised hierarchical clustering analysis of RDM values segregated two independent control groups together, along with the non-tumorigen myclobutanil. The two tumorigenic conazoles clustered together in a distinct grouping. Partitioning around mediods of RDM values into two clusters also groups the triadimefon and propiconazole together in one cluster and the two control groups and myclobutanil together in a second cluster. Principal component analysis of these results identifies two components that account for 88.3% of the variability in the points. Taken together, these results are consistent with the hypothesis that propiconazole- and triadimefon-induced mutations do not represent clonal expansion of background mutations and support the hypothesis that they arise from the accumulation of reactive electrophilic metabolic intermediates within the liver in vivo. PMID:20064898

Ross, Jeffrey A; Leavitt, Sharon A

2010-05-01

73

In vivo imaging of subcutaneous structures using functional photoacoustic microscopy  

Microsoft Academic Search

Functional photoacoustic microscopy (fPAM) is a hybrid technology that permits noninvasive imaging of the optical absorption contrast in subcutaneous biological tissues. fPAM uses a focused ultrasonic transducer to detect high-frequency photoacoustic (PA) signals. Volumetric images of biological tissues can be formed by two-dimensional raster scanning, and functional parameters can be further extracted from spectral measurements. fPAM is safe and applicable

Hao F Zhang; Konstantin Maslov; Lihong V Wang

2007-01-01

74

In vivo functional imaging of human cone photoreceptors  

PubMed Central

We evaluate a novel non-invasive optical technique for observing fast physiological processes, in particular phototransduction, in single photoreceptor cells in the living human eye. The method takes advantage of the interference of multiple reflections within the outer segments (OS) of cones. This self-interference phenomenon is highly sensitive to phase changes such as those caused by variations in refractive index and scatter within the photoreceptor cell. A high-speed (192 Hz) flood-illumination retina camera equipped with adaptive optics (AO) is used to observe individual photoreceptors, and to monitor changes in their reflectance in response to visible stimuli (“scintillation”). AO and high frame rates are necessary for resolving individual cones and their fast temporal dynamics, respectively. Scintillation initiates within 5 to 10 ms after the onset of the stimulus flash, lasts 300 to 400 ms, is observed at visible and near-infrared (NIR) wavelengths, and is highly sensitive to the coherence length of the imaging light source. To our knowledge this is the first demonstration of in vivo optical imaging of the fast physiological processes that accompany phototransduction in individual photoreceptors.

Jonnal, Ravi S.; Rha, Jungtae; Zhang, Yan; Cense, Barry; Gao, Weihua; Miller, Donald T.

2008-01-01

75

In vivo functional imaging of human cone photoreceptors  

PubMed Central

We evaluate a novel non-invasive optical technique for observing fast physiological processes, in particular phototransduction, in single photoreceptor cells in the living human eye. The method takes advantage of the interference of multiple reflections within the outer segments (OS) of cones. This self-interference phenomenon is highly sensitive to phase changes such as those caused by variations in refractive index and scatter within the photoreceptor cell. A high-speed (192 Hz) flood-illumination retina camera equipped with adaptive optics (AO) is used to observe individual photoreceptors, and to monitor changes in their reflectance in response to visible stimuli (“scintillation”). AO and high frame rates are necessary for resolving individual cones and their fast temporal dynamics, respectively. Scintillation initiates within 5 to 10 ms after the onset of the stimulus flash, lasts 300 to 400 ms, is observed at visible and near-infrared (NIR) wavelengths, and is highly sensitive to the coherence length of the imaging light source. To our knowledge this is the first demonstration of in vivo optical imaging of the fast physiological processes that accompany phototransduction in individual photoreceptors.

Jonnal, Ravi S.; Rha, Jungtae; Zhang, Yan; Cense, Barry; Gao, Weihua; Miller, Donald T.

2009-01-01

76

The effects of flavanol-rich cocoa and aspirin on ex vivo platelet function  

Microsoft Academic Search

Background: Flavanols modulate platelet function in vitro, but less is known of their in vivo effects and how they compare to pharmacological platelet inhibitors. We investigated the effect of a flavanol-rich cocoa beverage (897 mg\\/ml) in combination with and in comparison to aspirin on platelet function and activation in healthy subjects. Methods and results: On separate test days in a

Debra A Pearson; Teresa G Paglieroni; Dietrich Rein; Ted Wun; Derek D Schramm; Janice F Wang; Roberta R Holt; Robert Gosselin; Harold H Schmitz; Carl L Keen

2002-01-01

77

Semiparametric estimation without searching in function space: Application to in vivo metabolite quantitation  

Microsoft Academic Search

Magnetic resonance spectroscopy (MRS) is the method of choice for noninvasive in vivo measurement of metabolites in patients. When the model function describing the acquired MRS signal is incomplete, semi-parametric techniques are required for estimation of the wanted metabolite concentrations. In this work, incompleteness means that the model function of the MRS signal decay is unknown. We devised the simplest

E. a Popa; D.A.b Karras; B. G. c Mertzios; D. M. d Sima; R. e De Beer; D. e Van Ormondt; D. a Graveron-Demilly

2011-01-01

78

Inhibition of Dopamine Release Via Presynaptic D2 Receptors: Time Course and Functional Characteristics In Vivo  

Microsoft Academic Search

Most neurotransmitters inhibit their own release through auto- receptors. However, the physiological functions of these pre- synaptic inhibitions are still poorly understood, in part because their time course and functional characteristics have not been described in vivo. Dopamine inhibits its own release through D2 autoreceptors. Here, the part played by autoinhibition in the relationship between impulse flow and dopamine release

Marianne Benoit-Marand; Emiliana Borrelli; Francois Gonon

2001-01-01

79

Multiple functions of Drosophila heat shock transcription factor in vivo.  

PubMed Central

Heat shock transcription factor (HSF) is a transcriptional activator of heat shock protein (hsp) genes in eukaryotes. In order to elucidate the physiological functions of HSF in Drosophila, we have isolated lethal mutations in the hsf gene. Using a conditional allele, we show that HSF has an essential role in the ability of the organism to survive extreme heat stress. In contrast to previous results obtained with yeast HSF, the Drosophila protein is dispensable for general cell growth or viability. However, it is required under normal growth conditions for oogenesis and early larval development. These two developmental functions of Drosophila HSF are genetically separable and appear not to be mediated through the induction of HSPs, implicating a novel action of HSF that may be unrelated to its characteristic function as a stress-responsive transcriptional activator.

Jedlicka, P; Mortin, M A; Wu, C

1997-01-01

80

Function and regulation of the Pem homeobox gene in vivo  

Microsoft Academic Search

Pem, a member of the PEPP homeobox family, is expressed in somatic cells in male and female reproductive tissues. In the adult murine testis, Pem is specifically expressed in Sertoli cells, where it is restricted to stages IV–VIII of the seminiferous epithelial cycle. To identify Pem's function in Sertoli cells, transgenic mice were generated that express Pem in Sertoli cells

Chad Michael Wayne

2002-01-01

81

Ex Vivo Lung Function Measurements in Precision-Cut Lung Slices (PCLS) from Chemical Allergen-Sensitized Mice Represent a Suitable Alternative to In Vivo Studies  

Microsoft Academic Search

A wide range of industrial chemicals can induce respiratory allergic reactions. Hence, there is an urgent need for methods identifying and characterizing the biological action of chemicals in the lung. Here, we present an easy, reliable alternative method to measure lung function changes ex vivo after exposure to chemical allergens and compare this to invasive in vivo measure- ments after

M. Henjakovic; C. Martin; H. G. Hoymann; K. Sewald; A. R. Ressmeyer; C. Dassow; G. Pohlmann; N. Krug; S. Uhlig; A. Braun

2008-01-01

82

Nucleotide-sugar transporters: structure, function and roles in vivo.  

PubMed

The glycosylation of glycoconjugates and the biosynthesis of polysaccharides depend on nucleotide-sugars which are the substrates for glycosyltransferases. A large proportion of these enzymes are located within the lumen of the Golgi apparatus as well as the endoplasmic reticulum, while many of the nucleotide-sugars are synthesized in the cytosol. Thus, nucleotide-sugars are translocated from the cytosol to the lumen of the Golgi apparatus and endoplasmic reticulum by multiple spanning domain proteins known as nucleotide-sugar transporters (NSTs). These proteins were first identified biochemically and some of them were cloned by complementation of mutants. Genome and expressed sequence tag sequencing allowed the identification of a number of sequences that may encode for NSTs in different organisms. The functional characterization of some of these genes has shown that some of them can be highly specific in their substrate specificity while others can utilize up to three different nucleotide-sugars containing the same nucleotide. Mutations in genes encoding for NSTs can lead to changes in development in Drosophila melanogaster or Caenorhabditis elegans, as well as alterations in the infectivity of Leishmania donovani. In humans, the mutation of a GDP-fucose transporter is responsible for an impaired immune response as well as retarded growth. These results suggest that, even though there appear to be a fair number of genes encoding for NSTs, they are not functionally redundant and seem to play specific roles in glycosylation. PMID:16981043

Handford, M; Rodriguez-Furlán, C; Orellana, A

2006-09-01

83

SAHA Enhances Synaptic Function and Plasticity In Vitro but Has Limited Brain Availability In Vivo and Does Not Impact Cognition  

PubMed Central

Suberoylanilide hydroxamic acid (SAHA) is an inhibitor of histone deacetylases (HDACs) used for the treatment of cutaneous T cell lymphoma (CTCL) and under consideration for other indications. In vivo studies suggest reducing HDAC function can enhance synaptic function and memory, raising the possibility that SAHA treatment could have neurological benefits. We first examined the impacts of SAHA on synaptic function in vitro using rat organotypic hippocampal brain slices. Following several days of SAHA treatment, basal excitatory but not inhibitory synaptic function was enhanced. Presynaptic release probability and intrinsic neuronal excitability were unaffected suggesting SAHA treatment selectively enhanced postsynaptic excitatory function. In addition, long-term potentiation (LTP) of excitatory synapses was augmented, while long-term depression (LTD) was impaired in SAHA treated slices. Despite the in vitro synaptic enhancements, in vivo SAHA treatment did not rescue memory deficits in the Tg2576 mouse model of Alzheimer’s disease (AD). Along with the lack of behavioral impact, pharmacokinetic analysis indicated poor brain availability of SAHA. Broader assessment of in vivo SAHA treatment using high-content phenotypic characterization of C57Bl6 mice failed to demonstrate significant behavioral effects of up to 150 mg/kg SAHA following either acute or chronic injections. Potentially explaining the low brain exposure and lack of behavioral impacts, SAHA was found to be a substrate of the blood brain barrier (BBB) efflux transporters Pgp and Bcrp1. Thus while our in vitro data show that HDAC inhibition can enhance excitatory synaptic strength and potentiation, our in vivo data suggests limited brain availability may contribute to the lack of behavioral impact of SAHA following peripheral delivery. These results do not predict CNS effects of SAHA during clinical use and also emphasize the importance of analyzing brain drug levels when interpreting preclinical behavioral pharmacology.

Hanson, Jesse E.; La, Hank; Plise, Emile; Chen, Yung-Hsiang; Ding, Xiao; Hanania, Taleen; Sabath, Emily V.; Alexandrov, Vadim; Brunner, Dani; Leahy, Emer; Steiner, Pascal; Liu, Lichuan; Scearce-Levie, Kimberly; Zhou, Qiang

2013-01-01

84

In vivo Analysis of Choroid Plexus Morphogenesis in Zebrafish  

PubMed Central

Background The choroid plexus (ChP), a component of the blood-brain barrier (BBB), produces the cerebrospinal fluid (CSF) and as a result plays a role in (i) protecting and nurturing the brain as well as (ii) in coordinating neuronal migration during neurodevelopment. Until now ChP development was not analyzed in living vertebrates due to technical problems. Methodology/Principal Findings We have analyzed the formation of the fourth ventricle ChP of zebrafish in the GFP-tagged enhancer trap transgenic line SqET33-E20 (Gateways) by a combination of in vivo imaging, histology and mutant analysis. This process includes the formation of the tela choroidea (TC), the recruitment of cells from rhombic lips and, finally, the coalescence of TC resulting in formation of ChP. In Notch-deficient mib mutants the first phase of this process is affected with premature GFP expression, deficient cell recruitment into TC and abnormal patterning of ChP. In Hedgehog-deficient smu mutants the second phase of the ChP morphogenesis lacks cell recruitment and TC cells undergo apoptosis. Conclusions/Significance This study is the first to demonstrate the formation of ChP in vivo revealing a role of Notch and Hedgehog signalling pathways during different developmental phases of this process.

Fong, Steven H.; Ye, Zhang-Rui; Korzh, Vladimir

2008-01-01

85

MITOCHONDRIA: Investigation of in vivo muscle mitochondrial function by (31)P magnetic resonance spectroscopy.  

PubMed

The most important function of mitochondria is the production of energy in the form of ATP. The socio-economic impact of human diseases that affect skeletal muscle mitochondrial function is growing, and improving their clinical management critically depends on the development of non-invasive assays to assess mitochondrial function and monitor the effects of interventions. (31)P magnetic resonance spectroscopy provides two approaches that have been used to assess in vivo ATP synthesis in skeletal muscle: measuring Pi?ATP exchange flux using saturation transfer in resting muscle, and measuring phosphocreatine recovery kinetics after exercise. However, Pi?ATP exchange does not represent net mitochondrial ATP synthesis flux and has no simple relationship with mitochondrial function. Post-exercise phosphocreatine recovery kinetics, on the other hand, yield reliable measures of muscle mitochondrial capacity in vivo, whose ability to define the site of functional defects is enhanced by combination with other non-invasive techniques. PMID:24569118

Prompers, Jeanine J; Wessels, Bart; Kemp, Graham J; Nicolay, Klaas

2014-05-01

86

Application of electrical stimulation for functional tissue engineering in vitro and in vivo  

NASA Technical Reports Server (NTRS)

The present invention provides new methods for the in vitro preparation of bioartificial tissue equivalents and their enhanced integration after implantation in vivo. These methods include submitting a tissue construct to a biomimetic electrical stimulation during cultivation in vitro to improve its structural and functional properties, and/or in vivo, after implantation of the construct, to enhance its integration with host tissue and increase cell survival and functionality. The inventive methods are particularly useful for the production of bioartificial equivalents and/or the repair and replacement of native tissues that contain electrically excitable cells and are subject to electrical stimulation in vivo, such as, for example, cardiac muscle tissue, striated skeletal muscle tissue, smooth muscle tissue, bone, vasculature, and nerve tissue.

Radisic, Milica (Inventor); Park, Hyoungshin (Inventor); Langer, Robert (Inventor); Freed, Lisa (Inventor); Vunjak-Novakovic, Gordana (Inventor)

2013-01-01

87

Space station functional relationships analysis  

NASA Technical Reports Server (NTRS)

A systems engineering process is developed to assist Space Station designers to understand the underlying operational system of the facility so that it can be physically arranged and configured to support crew productivity. The study analyzes the operational system proposed for the Space Station in terms of mission functions, crew activities, and functional relationships in order to develop a quantitative model for evaluation of interior layouts, configuration, and traffic analysis for any Station configuration. Development of the model involved identification of crew functions, required support equipment, criteria of assessing functional relationships, and tools for analyzing functional relationship matrices, as well as analyses of crew transition frequency, sequential dependencies, support equipment requirements, potential for noise interference, need for privacy, and overall compatability of functions. The model can be used for analyzing crew functions for the Initial Operating Capability of the Station and for detecting relationships among these functions. Note: This process (FRA) was used during Phase B design studies to test optional layouts of the Space Station habitat module. The process is now being automated as a computer model for use in layout testing of the Space Station laboratory modules during Phase C.

Tullis, Thomas S.; Bied, Barbra R.

1988-01-01

88

Stonustoxin: effects on neuromuscular function in vitro and in vivo.  

PubMed

Stonustoxin (8-50 micrograms/ml) produced a rapid and concentration-dependent rise in tension (contracture) of the electrically stimulated mouse hemidiaphragm followed by a gradual waning of tension from the peak to the baseline; the nerve-evoked and the directly (muscle)-evoked twitches of the hemidiaphragm were also progressively and irreversibly blocked in a time- and concentration-dependent manner. Stonustoxin (22 and 44 micrograms/ml) produced a similar rapid rise in tension of the chick biventer cervicis muscle as well as irreversible and concentration-dependent blockade of nerve-evoked twitches and contractures produced by acetylcholine (200 microM), carbachol (8 microM) and KCl (40 mM). The muscle contracture produced by stonustoxin was blocked by dantrolene sodium (6 microM) but not by tubocurarine (15 microM). Moreover, stonustoxin (40 micrograms/ml) did not inhibit nerve conduction in the toad sciatic nerve and stonustoxin (60 micrograms/ml) did not exhibit any anticholinesterase activity. The inhibition of neuromuscular function by stonustoxin in the mouse hemidiaphragm and chick biventer cervicis muscle can therefore be attributed to some irreversible myotoxic action(s) of the toxin, whereas the stonustoxin-induced muscle contractures could have been mediated via depolarization of muscle fibres. PMID:8079369

Low, K S; Gwee, M C; Yuen, R; Gopalakrishnakone, P; Khoo, H E

1994-05-01

89

Development and in vivo evaluation of papain-functionalized nanoparticles.  

PubMed

The aim of the present study was to develop a novel nanoparticulate delivery system being capable of penetrating the intestinal mucus layer by cleaving mucoglycoprotein substructures. Nanoparticles based on papain grafted polyacrylic acid (papain-g-PAA) were prepared via ionic gelation and labeled with fluorescein diacetate. In vitro, the proteolytic potential of papain modified nanoparticles was investigated by rheological measurements and diffusion studies across fresh porcine intestinal mucus. The presence of papain on the surface and inside the particles strongly decreases viscosity of the mucus leading to facilitated particle transition across the mucus layer. Results of the permeation studies revealed that enzyme grafted particles diffuse through mucus layer to a 3.0-fold higher extent than the same particles without enzyme. Furthermore, the penetration behavior of the nanocarriers along the gastrointestinal tract of Sprague Dawley rats was investigated after oral administration of nanoparticles formulated as enteric coated capsules. The majority of the papain functionalized particles was able to traverse across the mucus layer and remained in the duodenum and jejunum of the small intestine where drug absorption primarily occurs. Polymeric nanoparticles combined with mucolytic enzymes that are capable of overcoming intestinal mucus barriers offer an encouraging new attempt for mucosal drug delivery. PMID:24373995

Müller, Christiane; Perera, Glen; König, Verena; Bernkop-Schnürch, Andreas

2014-05-01

90

Functional data analysis in hydrology  

NASA Astrophysics Data System (ADS)

River flow records are essential for the prevention of flood risks and the effective planning and management of water resources among other engineering activities. The graphical representation of the temporal variation of flow over a period of time constitutes a hydrograph. The latter is usually characterized by its peak, volume and duration. These features are considered jointly in order to take into account their dependence structure within multivariate hydrological frequency analysis (HFA). However, all these multivariate HFA approaches are based on the analysis of a limited number of characteristics and do not make use of the full information provided by the hydrograph. This talk is to propose to introduce a new framework for HFA using the hydrographs as curves to be functional data. In the context, called functional data analysis (FDA), the whole hydrograph is considered as one infinite-dimensional observation. The FDA context in HFA has a number of advantages. A number of functional tools are introduced and adapted to flood HFA with a focus on exploratory analysis. A real-world flood analysis case-study is considered.

Chebana, F.; Dabo-Niang, S.; Ouarda, T.

2013-12-01

91

Some Recent Developments In The In Vivo Analysis Of Body Elements And Body Composition  

Microsoft Academic Search

The programme of research on the in vivo analysis of body elements and body composition being carried out by the Swansea In Vivo Analysis Research Group (SIVARG) is reviewed. Facilities for multi-element neutron activation analysis, neutron inelastic scattering, X-Ray fluorescence, SQUID biomagnetometry, and electromagnetic tissue resonance impedance monitoring which have been designed and constructed within the group are described. The

J. Dutton; C. J. Evans; W. D. Morgan; D. Rassi; S. J. S. Ryde; N. H. Saunders; A. Sivyer

1991-01-01

92

Kinetic analysis of pre-ribosome structure in vivo.  

PubMed

Pre-ribosomal particles undergo numerous structural changes during maturation, but their high complexity and short lifetimes make these changes very difficult to follow in vivo. In consequence, pre-ribosome structure and composition have largely been inferred from purified particles and analyzed in vitro. Here we describe techniques for kinetic analyses of the changes in pre-ribosome structure in living cells of Saccharomyces cerevisiae. To allow this, in vivo structure probing by DMS modification was combined with affinity purification of newly synthesized 20S pre-rRNA over a time course of metabolic labeling with 4-thiouracil. To demonstrate that this approach is generally applicable, we initially analyzed the accessibility of the region surrounding cleavage site D site at the 3' end of the mature 18S rRNA region of the pre-rRNA. This revealed a remarkably flexible structure throughout 40S subunit biogenesis, with little stable RNA-protein interaction apparent. Analysis of folding in the region of the 18S central pseudoknot was consistent with previous data showing U3 snoRNA-18S rRNA interactions. Dynamic changes in the structure of the hinge between helix 28 (H28) and H44 of pre-18S rRNA were consistent with recently reported interactions with the 3' guide region of U3 snoRNA. Finally, analysis of the H18 region indicates that the RNA structure matures early, but additional protection appears subsequently, presumably reflecting protein binding. The structural analyses described here were performed on total, affinity-purified, newly synthesized RNA, so many classes of RNA and RNA-protein complex are potentially amenable to this approach. PMID:23093724

Swiatkowska, Agata; Wlotzka, Wiebke; Tuck, Alex; Barrass, J David; Beggs, Jean D; Tollervey, David

2012-12-01

93

In Vivo Evaluation of Vena Caval Filters: Can Function Be Linked to Design Characteristics?  

Microsoft Academic Search

Purpose: To compare the five vena caval filters marketed in the United States and one investigational vena caval filter and to determine whether there is an association between their design and their in vivo function.Methods: Four of each type of filter-Simon Nitinol (SN), Bird's Nest (BN), Vena Tech (VT), Greenfield stainless steel (PSGF), Greenfield titanium (TGF), and the investigational stent

Mary C. Proctor; Kyung J. Cho; Lazar J. Greenfield

2000-01-01

94

EFFECTS OF BROMODICHLOROMETHANE (BDCM) ON EX VIVO LUTEAL FUNCTION IN THE F344 RAT DURING PREGNANCY  

EPA Science Inventory

Effects of Bromodichloromethane (BDCM) on Ex Vivo Luteal Function In the Pregnant F344 Rat Susan R. Bielmeier1, Ashley S. Murr2, Deborah S. Best2, Jerome M. Goldman2, and Michael G. Narotsky2 1Curriculum in Toxicology, Univ. of North Carolina, Chapel Hill, NC 27599,...

95

EFFECTS OF BROMODICHLOROMETHANE (BDCM) ON EX VIVO LUTEAL FUNCTION IN THE PREGNANT F344 RAT  

EPA Science Inventory

EFFECTS OF BROMODICHLOROMETHANE (BDCM) ON EX VIVO LUTEAL FUNCTION IN THE PREGNANT F344 RAT. S. R. Bielmeier1, A. S. Murr2, D. S. Best2, J. M. Goldman2, and M. G. Narotsky2 1 Curriculum in Toxicology, Univ. of North Carolina, Chapel Hill, NC, USA 2 Reproductive T...

96

EFFECTS OF BROMODICHLOROMETHANE (BDCM) ON EX VIVO LUTEAL FUNCTION IN THE F344 RAT  

EPA Science Inventory

EFFECTS OF BROMODICHLOROMETHANE (BDCM) ON EX VIVO LUTEAL FUNCTION IN THE PREGNANT F344 RAT. S. R. Bielmeier1, A. S. Murr2, D. S. Best2, J. M. Goldman2, and M. G. Narotsky2 1 Curriculum in Toxicology, Univ. of North Carolina, Chapel Hill, NC, USA 2 Reproductive T...

97

Anti-CEA-functionalized superparamagnetic iron oxide nanoparticles for examining colorectal tumors in vivo.  

PubMed

Although the biomarker carcinoembryonic antigen (CEA) is expressed in colorectal tumors, the utility of an anti-CEA-functionalized image medium is powerful for in vivo positioning of colorectal tumors. With a risk of superparamagnetic iron oxide nanoparticles (SPIONPs) that is lower for animals than other material carriers, anti-CEA-functionalized SPIONPs were synthesized in this study for labeling colorectal tumors by conducting different preoperatively and intraoperatively in vivo examinations. In magnetic resonance imaging (MRI), the image variation of colorectal tumors reached the maximum at approximately 24 h. However, because MRI requires a nonmetal environment, it was limited to preoperative imaging. With the potentiality of in vivo screening and intraoperative positioning during surgery, the scanning superconducting-quantum-interference-device biosusceptometry (SSB) was adopted, showing the favorable agreement of time-varied intensity with MRI. Furthermore, biological methodologies of different tissue staining methods and inductively coupled plasma (ICP) yielded consistent results, proving that the obtained in vivo results occurred because of targeted anti-CEA SPIONPs. This indicates that developed anti-CEA SPIONPs owe the utilities as an image medium of these in vivo methodologies. PMID:24103079

Huang, Kai-Wen; Chieh, Jen-Jie; Lin, In-Tsang; Horng, Herng-Er; Yang, Hong-Chang; Hong, Chin-Yih

2013-01-01

98

Effects of ACL Reconstruction on In-Vivo, Dynamic Knee Function  

PubMed Central

Synopsis The purposes of this article are to discuss key factors for assessing joint function, to present some recent findings and to address the future directions for evaluating the function of the ACL-injured/reconstructed knees. Well-designed studies, using state-of-the art tools to assess knee kinematics under in vivo, dynamic, high-loading conditions, are necessary to evaluate the relative performance of different procedures for restoring normal joint motion.

Tashman, Scott; Araki, Daisuke

2012-01-01

99

Effects of anterior cruciate ligament reconstruction on in vivo, dynamic knee function.  

PubMed

The purposes of this article are to discuss key factors for assessing joint function, to present some recent findings, and to address the future directions for evaluating the function of the anterior cruciate ligament-injured/reconstructed knees. Well-designed studies, using state-of-the art tools to assess knee kinematics under in vivo, dynamic, high-loading conditions, are necessary to evaluate the relative performance of different procedures for restoring normal joint motion. PMID:23177461

Tashman, Scott; Araki, Daisuke

2013-01-01

100

Quantifying long-term microelectrode array functionality using chronic in vivo impedance testing.  

PubMed

Long-term acquisition of high-quality neural recordings is a cornerstone of neuroprosthetic system design. Mitigating the experimental variability of chronically implanted arrays has been a formidable task because the sensor recording sites can be influenced by biotic and abiotic responses. Several studies have implicated changes in electrical interface impedance as a preliminary marker to infer electrode viability. Microelectrode impedance plays an important role in the monitoring of low amplitude and high-resolution extracellular neural signals. In this work, we seek to quantify long-term microelectrode array functionality and derive an impedance-based predictor for electrode functionality that correlates the recording site electrical properties with the functional neuronal recordings in vivo. High temporal resolution metrics of this type would allow one to assess, predict, and improve electrode performance in the future. In a large cohort of animals, we performed daily impedance measurements and neural signal recordings over long periods (up to 21 weeks) of time in rats using tungsten microwire arrays implanted into the somatosensory cortex. This study revealed that there was a time-varying trend in the modulation of impedance that was related to electrode performance. Single units were best detected from electrodes at time points when the electrode entered into the 40-150 K? impedance range. This impedance trend was modeled across the full cohort of animals to predict future electrode performance. The model was tested on data from all animals and was able to provide predictions of electrode performance chronically. Insight from this study can be combined with knowledge of electrode materials and histological analysis to provide a more comprehensive predictive model of electrode failure in the future. PMID:22442134

Prasad, Abhishek; Sanchez, Justin C

2012-04-01

101

Quantifying long-term microelectrode array functionality using chronic in vivo impedance testing  

NASA Astrophysics Data System (ADS)

Long-term acquisition of high-quality neural recordings is a cornerstone of neuroprosthetic system design. Mitigating the experimental variability of chronically implanted arrays has been a formidable task because the sensor recording sites can be influenced by biotic and abiotic responses. Several studies have implicated changes in electrical interface impedance as a preliminary marker to infer electrode viability. Microelectrode impedance plays an important role in the monitoring of low amplitude and high-resolution extracellular neural signals. In this work, we seek to quantify long-term microelectrode array functionality and derive an impedance-based predictor for electrode functionality that correlates the recording site electrical properties with the functional neuronal recordings in vivo. High temporal resolution metrics of this type would allow one to assess, predict, and improve electrode performance in the future. In a large cohort of animals, we performed daily impedance measurements and neural signal recordings over long periods (up to 21 weeks) of time in rats using tungsten microwire arrays implanted into the somatosensory cortex. This study revealed that there was a time-varying trend in the modulation of impedance that was related to electrode performance. Single units were best detected from electrodes at time points when the electrode entered into the 40-150 K? impedance range. This impedance trend was modeled across the full cohort of animals to predict future electrode performance. The model was tested on data from all animals and was able to provide predictions of electrode performance chronically. Insight from this study can be combined with knowledge of electrode materials and histological analysis to provide a more comprehensive predictive model of electrode failure in the future.

Prasad, Abhishek; Sanchez, Justin C.

2012-04-01

102

Comparative analysis of SV40 17kT and LT function in vivo demonstrates that LT's C-terminus re-programs hepatic gene expression and is necessary for tumorigenesis in the liver  

PubMed Central

Transformation by Simian Virus 40 (SV40) large T antigen (LT) is mediated in large part by its interaction with a variety of cellular proteins at distinct binding domains within LT. While the interaction of LT's N-terminus with the tumor suppressor Rb is absolutely required for LT-dependent transformation, the requirement for the interaction of LT's C-terminus with p53 is less clear and cell- and context-dependent. Here, we report a line of transgenic mice expressing a doxycycline-inducible liver-specific viral transcript that produces abundant 17kT, a naturally occurring SV40 early product that is co-linear with LT for the first 131 amino acids and that binds to Rb, but not p53. Comparative analysis of livers of transgenic mice expressing either 17kT or full length LT demonstrates that 17kT stimulates cell proliferation and induces hepatic hyperplasia but is incapable of inducing hepatic dysplasia or promoting hepatocarcinogenesis. Gene expression profiling demonstrates that 17kT and LT invoke a set of shared molecular signatures consistent with the action of LT's N-terminus on Rb-E2F-mediated control of hepatocyte transcription. However, 17kT also induces a unique set of genes, many of which are known transcriptional targets of p53, while LT actively suppresses them. LT also uniquely deregulates the expression of a subset of genes within the imprinted network and rapidly re-programs hepatocyte gene expression to a more fetal-like state. Finally, we provide evidence that the LT/p53 complex provides a gain-of-function for LT-dependent transformation in the liver, and confirm the absolute requirement for LT's C-terminus for liver tumor development by demonstrating that phosphatase and tensin homolog (PTEN)-deficiency readily cooperates with LT, but not 17kT, for tumorigenesis. These results confirm independent and inter-dependent functions for LT's N- and C-terminus and emphasize differences in the requirements for LT's C-terminus in cell-type dependent transformation.

Comerford, S A; Schultz, N; Hinnant, E A; Klapproth, S; Hammer, R E

2012-01-01

103

The proximal element of the beta globin locus control region is not functionally required in vivo.  

PubMed Central

In addition to local sequence elements the regulation of the high-level, development- and tissue-specific expression of the human beta globin gene cluster appears to require distant regulatory sequences which have been termed locus control region. In the chromatin of erythroid cells the locus control region is characterized by four DNaseI hypersensitive sites that are located 6-18 kb 5' of the epsilon globin gene. The definition of the sequences minimally required for locus control region activity is likely to further the understanding of its physiology and will be of interest for the development of somatic gene therapy strategies of the hemoglobinopathies. We present here the analysis of a family with a 3,030-bp deletion of sequences upstream of the epsilon globin gene including the most 3' locus control region element and cosegregating beta(0) thalassemia. The deletion is linked in cis to a structurally and functionally normal beta globin gene. The proximal element of the locus control region does not therefore appear to be necessary for beta globin gene activity in vivo. Images

Kulozik, A E; Bail, S; Bellan-Koch, A; Bartram, C R; Kohne, E; Kleihauer, E

1991-01-01

104

In vivo analysis of Caenorhabditis elegans noncoding RNA promoter motifs  

PubMed Central

Background Noncoding RNAs (ncRNAs) play important roles in a variety of cellular processes. Characterizing the transcriptional activity of ncRNA promoters is therefore a critical step toward understanding the complex cellular roles of ncRNAs. Results Here we present an in vivo transcriptional analysis of three C. elegans ncRNA upstream motifs (UM1-3). Transcriptional activity of all three motifs has been demonstrated, and mutational analysis revealed differential contributions of different parts of each motif. We showed that upstream motif 1 (UM1) can drive the expression of green fluorescent protein (GFP), and utilized this for detailed analysis of temporal and spatial expression patterns of 5 SL2 RNAs. Upstream motifs 2 and 3 do not drive GFP expression, and termination at consecutive T runs suggests transcription by RNA polymerase III. The UM2 sequence resembles the tRNA promoter, and is actually embedded within its own short-lived, primary transcript. This is a structure which is also found at a few plant and yeast loci, and may indicate an evolutionarily very old dicistronic transcription pattern in which a tRNA serves as a promoter for an adjacent snoRNA. Conclusion The study has demonstrated that the three upstream motifs UM1-3 have promoter activity. The UM1 sequence can drive expression of GFP, which allows for the use of UM1::GFP fusion constructs to study temporal-spatial expression patterns of UM1 ncRNA loci. The UM1 loci appear to act in concert with other upstream sequences, whereas the transcriptional activities of the UM2 and UM3 are confined to the motifs themselves.

Li, Tiantian; He, Housheng; Wang, Yunfei; Zheng, Haixia; Skogerb?, Geir; Chen, Runsheng

2008-01-01

105

In Vivo Enhancer Analysis Chromosome 16 Conserved NoncodingSequences  

SciTech Connect

The identification of enhancers with predicted specificitiesin vertebrate genomes remains a significant challenge that is hampered bya lack of experimentally validated training sets. In this study, weleveraged extreme evolutionary sequence conservation as a filter toidentify putative gene regulatory elements and characterized the in vivoenhancer activity of human-fish conserved and ultraconserved1 noncodingelements on human chromosome 16 as well as such elements from elsewherein the genome. We initially tested 165 of these extremely conservedsequences in a transgenic mouse enhancer assay and observed that 48percent (79/165) functioned reproducibly as tissue-specific enhancers ofgene expression at embryonic day 11.5. While driving expression in abroad range of anatomical structures in the embryo, the majority of the79 enhancers drove expression in various regions of the developingnervous system. Studying a set of DNA elements that specifically droveforebrain expression, we identified DNA signatures specifically enrichedin these elements and used these parameters to rank all ~;3,400human-fugu conserved noncoding elements in the human genome. The testingof the top predictions in transgenic mice resulted in a three-foldenrichment for sequences with forebrain enhancer activity. These datadramatically expand the catalogue of in vivo-characterized human geneenhancers and illustrate the future utility of such training sets for avariety of iological applications including decoding the regulatoryvocabulary of the human genome.

Pennacchio, Len A.; Ahituv, Nadav; Moses, Alan M.; Nobrega,Marcelo; Prabhakar, Shyam; Shoukry, Malak; Minovitsky, Simon; Visel,Axel; Dubchak, Inna; Holt, Amy; Lewis, Keith D.; Plajzer-Frick, Ingrid; Akiyama, Jennifer; De Val, Sarah; Afzal, Veena; Black, Brian L.; Couronne, Olivier; Eisen, Michael B.; Rubin, Edward M.

2006-02-01

106

Increased in vivo stability and functional lifetime of an implantable glucose sensor through platinum catalysis.  

PubMed

Understanding and improving in vivo materials related to signal stability and preservation for active chemical sensor and biosensor transduction systems is critical in achieving implantable medical sensors for long-term in vivo applications. During human in vivo clinical testing of an implantable glucose sensor based on a glucose sensitive hydrogel, post-explant analysis showed that the boronate recognition element had been oxidized from the fluorescent indicator, causing a rapid loss of signal within hours after implant. Additional wet-bench analytical evidence and reproduction in vitro suggests reactive oxygen species, particularly hydrogen peroxide (H2O2), stemming from natural inflammatory response to the material, to be the cause of the observed oxidative de-boronation. A 3-nm thick deposition of metallic platinum (Pt) placed by plasma sputtering onto the porous surface of the hydrogel, showed immediate protection from sensor signal loss due to oxidation both in vitro and in vivo, greatly extending the useful lifetime of the implantable glucose sensor from 1 day to an expected ?6 months. This finding may represent a new strategy to protect an implanted material and/or device from in vivo oxidative damage, leading to much improved overall stability and reliability for long-term applications. PMID:23071075

Colvin, Arthur E; Jiang, Hui

2013-05-01

107

In Vivo Function of Tryptophans in the Arabidopsis UV-B Photoreceptor UVR8[W  

PubMed Central

Arabidopsis thaliana UV RESISTANCE LOCUS8 (UVR8) is a photoreceptor specifically for UV-B light that initiates photomorphogenic responses in plants. UV-B exposure causes rapid conversion of UVR8 from dimer to monomer, accumulation in the nucleus, and interaction with CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1), which functions with UVR8 in UV-B responses. Studies in yeast and with purified UVR8 implicate several tryptophan amino acids in UV-B photoreception. However, their roles in UV-B responses in plants, and the functional significance of all 14 UVR8 tryptophans, are not known. Here we report the functions of the UVR8 tryptophans in vivo. Three tryptophans in the ?-propeller core are important in maintaining structural stability and function of UVR8. However, mutation of three other core tryptophans and four at the dimeric interface has no apparent effect on function in vivo. Mutation of three tryptophans implicated in UV-B photoreception, W233, W285, and W337, impairs photomorphogenic responses to different extents. W285 is essential for UVR8 function in plants, whereas W233 is important but not essential for function, and W337 has a lesser role. Ala mutants of these tryptophans appear monomeric and constitutively bind COP1 in plants, but their responses indicate that monomer formation and COP1 binding are not sufficient for UVR8 function.

O'Hara, Andrew; Jenkins, Gareth I.

2012-01-01

108

Functionalized gold nanoparticles: a detailed in vivo multimodal microscopic brain distribution study  

NASA Astrophysics Data System (ADS)

In the present study, the in vivo distribution of polyelectrolyte multilayer coated gold nanoparticles is shown, starting from the living animal down to cellular level. The coating was designed with functional moieties to serve as a potential nano drug for prion disease. With near infrared time-domain imaging we followed the biodistribution in mice up to 7 days after intravenous injection of the nanoparticles. The peak concentration in the head of mice was detected between 19 and 24 h. The precise particle distribution in the brain was studied ex vivo by X-ray microtomography, confocal laser and fluorescence microscopy. We found that the particles mainly accumulate in the hippocampus, thalamus, hypothalamus, and the cerebral cortex.In the present study, the in vivo distribution of polyelectrolyte multilayer coated gold nanoparticles is shown, starting from the living animal down to cellular level. The coating was designed with functional moieties to serve as a potential nano drug for prion disease. With near infrared time-domain imaging we followed the biodistribution in mice up to 7 days after intravenous injection of the nanoparticles. The peak concentration in the head of mice was detected between 19 and 24 h. The precise particle distribution in the brain was studied ex vivo by X-ray microtomography, confocal laser and fluorescence microscopy. We found that the particles mainly accumulate in the hippocampus, thalamus, hypothalamus, and the cerebral cortex. Electronic supplementary information (ESI) available: Fig. S1-S6. See DOI: 10.1039/c0nr00345j

Sousa, Fernanda; Mandal, Subhra; Garrovo, Chiara; Astolfo, Alberto; Bonifacio, Alois; Latawiec, Diane; Menk, Ralf Hendrik; Arfelli, Fulvia; Huewel, Sabine; Legname, Giuseppe; Galla, Hans-Joachim; Krol, Silke

2010-12-01

109

Uptake of postprandial lipoproteins into bone in vivo: impact on osteoblast function.  

PubMed

Dietary lipids and lipophilic vitamins are transported by postprandial lipoproteins and are required for bone metabolism. Despite that, it remains unknown whether bone cells are involved in the uptake of circulating postprandial lipoproteins in vivo. The current study was performed to investigate a putative participation of bone in the systemic postprandial lipoprotein metabolism in mice, to identify potentially involved cell type populations and to analyze whether lipoprotein uptake affects bone function in vivo. As a model for the postprandial state, chylomicron remnants (CR) were injected intravenously into mice. Next to the liver and compared to other organs, bone appeared to be the second most important organ for the clearance of radiolabeled CR particles from the circulation in vivo. In addition, uptake of radiolabeled CR by primary murine osteoblasts and hepatocytes was quantified to be in a similar range in vitro. A complementary approach with fluorescently labeled CR and immunohistochemical staining for apoE proved that intact CR particles were taken up into bone and liver. Electron microscopy localization studies of bone sections revealed CR uptake into sinusoidal endothelial cells, macrophages and osteoblasts. The relative amount of radiolabeled CR uptake into femoral cortical bone, representing predominantly osteoblasts, and bone marrow, representing predominantly non-osteoblast cells, was within the same range. Most importantly, the injection of vitamin K1-enriched CR resulted in an increase of the degree of osteocalcin carboxylation in vivo while total osteocalcin concentrations remained unaffected, giving functional proof that osteoblasts process CR in vivo. In conclusion, here we demonstrate that bone is involved in the postprandial lipoprotein metabolism in mice. Osteoblasts participate in CR clearance from the circulation, which has a direct impact on the secretory function of osteoblasts. PMID:18538644

Niemeier, Andreas; Niedzielska, Dagmara; Secer, Rukiye; Schilling, Arndt; Merkel, Martin; Enrich, Carlos; Rensen, Patrick C N; Heeren, Joerg

2008-08-01

110

Transcriptional Regulation of Rod Photoreceptor Homeostasis Revealed by In Vivo NRL Targetome Analysis  

PubMed Central

A stringent control of homeostasis is critical for functional maintenance and survival of neurons. In the mammalian retina, the basic motif leucine zipper transcription factor NRL determines rod versus cone photoreceptor cell fate and activates the expression of many rod-specific genes. Here, we report an integrated analysis of NRL-centered gene regulatory network by coupling chromatin immunoprecipitation followed by high-throughput sequencing (ChIP–Seq) data from Illumina and ABI platforms with global expression profiling and in vivo knockdown studies. We identified approximately 300 direct NRL target genes. Of these, 22 NRL targets are associated with human retinal dystrophies, whereas 95 mapped to regions of as yet uncloned retinal disease loci. In silico analysis of NRL ChIP–Seq peak sequences revealed an enrichment of distinct sets of transcription factor binding sites. Specifically, we discovered that genes involved in photoreceptor function include binding sites for both NRL and homeodomain protein CRX. Evaluation of 26 ChIP–Seq regions validated their enhancer functions in reporter assays. In vivo knockdown of 16 NRL target genes resulted in death or abnormal morphology of rod photoreceptors, suggesting their importance in maintaining retinal function. We also identified histone demethylase Kdm5b as a novel secondary node in NRL transcriptional hierarchy. Exon array analysis of flow-sorted photoreceptors in which Kdm5b was knocked down by shRNA indicated its role in regulating rod-expressed genes. Our studies identify candidate genes for retinal dystrophies, define cis-regulatory module(s) for photoreceptor-expressed genes and provide a framework for decoding transcriptional regulatory networks that dictate rod homeostasis.

Hao, Hong; Kim, Douglas S.; Klocke, Bernward; Johnson, Kory R.; Cui, Kairong; Gotoh, Norimoto; Zang, Chongzhi; Gregorski, Janina; Gieser, Linn; Peng, Weiqun; Fann, Yang; Seifert, Martin; Zhao, Keji; Swaroop, Anand

2012-01-01

111

In vitro and in vivo functional characterization of gutless recombinant SV40-derived CFTR vectors.  

PubMed

In cystic fibrosis (CF), respiratory failure caused by progressive airway obstruction and tissue damage is primarily a result of the aberrant inflammatory responses to lung infections with Pseudomonas aeruginosa. Despite considerable improvement in patient survival, conventional therapies are mainly supportive. Recent progress toward gene therapy for CF has been encouraging; however, several factors such as immune response and transduced cell turnover remain as potential limitations to CF gene therapy. As alternative gene therapy vectors for CF, we examined the feasibility of using recombinant SV40-derived vectors (rSV40s), which may circumvent some of these obstacles. To accommodate the large cystic fibrosis transmembrane conductance regulator (CFTR) cDNA, we removed not only SV40 Tag genes, but also all capsid genes. We, therefore, tested whether 'gutless' rSV40s could be packaged and were able to express a functional human CFTR cDNA. The results from our in vitro analysis determined that rSV40-CFTR was able to successfully result in the expression of CFTR protein, which localized to the plasma membrane and restored channel function to CFTR-deficient cells. Similarly, in vivo experiments delivering rSV40-CFTR to the lungs of Cftr-/- mice resulted in a reduction of the pathology associated with intra-tracheal P. aeruginosa challenge. rSV40-CFTR-treated mice had less weight loss when compared with control-treated mice as well as demonstrably reduced lung inflammation as evidence by histology and reduced inflammatory cytokines in the broncho-alveolar lavage. The reduction in inflammatory cytokine levels led to an evident decrease in neutrophil influx to the airways. These results indicate that further study of the application of rSV40-CFTR to CF gene therapy is warranted. PMID:19890354

Mueller, C; Strayer, M S; Sirninger, J; Braag, S; Branco, F; Louboutin, J-P; Flotte, T R; Strayer, D S

2010-02-01

112

Ex vivo lung function measurements in precision-cut lung slices (PCLS) from chemical allergen-sensitized mice represent a suitable alternative to in vivo studies.  

PubMed

A wide range of industrial chemicals can induce respiratory allergic reactions. Hence, there is an urgent need for methods identifying and characterizing the biological action of chemicals in the lung. Here, we present an easy, reliable alternative method to measure lung function changes ex vivo after exposure to chemical allergens and compare this to invasive in vivo measurements after sensitization with the industrial chemicals trimellitic anhydride (TMA) and 2,4-dinitrochlorobenzene (DNCB). Female BALB/c mice were sensitized epicutaneously with the respiratory allergen TMA and the contact sensitizer DNCB. The early allergic response to TMA and DNCB was registered in vivo and ex vivo on day 21 after inhalational challenge with dry standardized aerosols or after exposure of precision-cut lung slices (PCLS) to dissolved allergen. Airway hyperresponsiveness (AHR) to increasing doses of methacholine (MCh) was measured on the next day in vivo and ex vivo. Bronchoalveolar lavage (BAL) was performed for immunological characterization of local inflammation. TMA-sensitized mice showed AHR to MCh in vivo (ED(50): 0.06 microg MCh vs. 0.21 microg MCh in controls) and in PCLS (EC(50): 0.24 microM MCh vs. 0.4 microM MCh). TMA-treated animals showed increased numbers of eosinophils (12.8 x 10(4) vs. 0.7 x 10(4)) and elevated eotaxin-2 concentrations (994 pg/ml vs. 167 pg/ml) in BAL fluid 24 h after allergen challenge. In contrast, none of these parameters differed after sensitization with DNCB. The present study suggests that the effects of low molecular weight allergens, like TMA and DNCB, on ex vivo lung functions tested in PCLS reflect the in vivo situation. PMID:18775882

Henjakovic, M; Martin, C; Hoymann, H G; Sewald, K; Ressmeyer, A R; Dassow, C; Pohlmann, G; Krug, N; Uhlig, S; Braun, A

2008-12-01

113

Effect of in vivo chronic exposure to clotrimazole on zebrafish testis function.  

PubMed

Clotrimazole is an azole fungicide used as a human pharmaceutical that is known to inhibit cytochrome P450 (CYP) enzymatic activities, including several steroidogenic CYP. In a previous report, we showed that a 7-day exposure to clotrimazole induced the expression of genes related to steroidogenesis in the testes as a compensatory response, involving the activation of the Fsh/Fshr pathway. In this context, the aim of the present study was to assess the effect of an in vivo 21-day chronic exposure to clotrimazole (30-197 ?g/L) on zebrafish testis function, i.e., spermatogenesis and androgen release. The experimental design combined (1) gene transcript levels measurements along the brain-pituitary-gonad axis, (2) 11-ketotestosterone (11-KT) quantification in the blood, and (3) histology of the testes, including morphometric analysis. The chronic exposure led to an induction of steroidogenesis-related genes and fshr in the testes as well as fsh? in the pituitary. Moreover, increases of the gonadosomatic index and of the volume proportion of interstitial Leydig cells were observed in clotrimazole-exposed fish. In accordance with these histological observations, the circulating concentration of 11-KT had increased. Morphometric analysis of the testes did not show an effect of clotrimazole on meiotic (spermatocytes) or postmeiotic (spermatids and spermatozoa) stages, but we observed an increase in the number of type A spermatogonia, in agreement with an increase in mRNA levels of piwil1, a specific molecular marker of type A spermatogonia. Our study demonstrated that clotrimazole is able to affect testicular physiology and raised further concern about the impact of clotrimazole on reproduction. PMID:23340899

Baudiffier, Damien; Hinfray, Nathalie; Ravaud, Catherine; Creusot, Nicolas; Chadili, Edith; Porcher, Jean-Marc; Schulz, Rüdiger W; Brion, François

2013-05-01

114

Functional imaging of pitch analysis.  

PubMed

This work addresses the brain basis for the analysis of pitch and pitch patterns required for normal musical perception. Recent functional imaging experiments are consistent with a hierarchical scheme for the analysis of pitch. Mechanisms in the ascending auditory pathway to the primary auditory cortex allow the representation of the spectral and temporal features of individual notes required for the perception of their pitch. Converging experiments where pitch strength is manipulated in different ways suggest that there may be a "pitch center" in the lateral part of Heschl's gyrus, adjacent to the primary auditory area. The suggestion is that there is a representation in this area that correlates with the perception of pitch rather than a simple mapping of physical stimulus characteristics. The analysis of patterns of pitch such as melodies, as opposed to the pitch of individual notes, involves much more distributed processing in the superior temporal lobes and frontal lobes. Involvement of the frontal lobe in pitch pattern analysis may in part reflect whether subjects analyze the pitch patterns in order to carry out an output task. PMID:14681116

Griffiths, Timothy D

2003-11-01

115

In vivo biodistribution and toxicology of functionalized nano-graphene oxide in mice after oral and intraperitoneal administration.  

PubMed

Graphene oxide (GO) and its functionalized derivatives have attracted great attention in biomedicine in recent years. A number of groups including ours have studied the in vivo behaviors of functionalized nano-graphene after intravenous injection or inhalation, and uncovered the surface coating & size dependent biodistribution and toxicology profiles for this type of nanomaterials. However, the fate of GO derivatives in animals after oral feeding and intraperitoneal (i.p.) injection, which are two other major drug administration routes, remain unclear. Therefore, in this work, we sought to systematically investigate in vivo biodistribution and potential toxicity of as-made GO and a number of polyethylene glycol (PEG) functionalized GO derivatives with different sizes and surface coatings, after oral and intraperitoneal administration at high doses. It is found that (125)I labeled PEGylated GO derivatives show no obvious tissue uptake via oral administration, indicating the rather limited intestinal adsorption of those nanomaterials. In contrast, high accumulation of PEGyalted GO derivatives, but not as-made GO, in the reticuloendothelial (RES) system including liver and spleen is observed after i.p. injection. Further investigations based on histological examination of organ slices and hematological analysis discover that although GO and PEGylated GO derivatives would retain in the mouse body over a long period of time after i.p. injection, their toxicity to the treated animals is insignificant. Our work is an important fundamental study that offers a deeper understanding of in vivo behaviors and toxicology of functionalized nano-graphene in animals, depending on their different administration routes. PMID:23340196

Yang, Kai; Gong, Hua; Shi, Xiaoze; Wan, Jianmei; Zhang, Youjiu; Liu, Zhuang

2013-04-01

116

A Dynamic Real Time In Vivo and Static Ex Vivo Analysis of Granulomonocytic Cell Migration in the Collagen-Induced Arthritis Model  

PubMed Central

Neutrophilic granulocytes and monocytes (granulomonocytic cells; GMC) drive the inflammatory process at the earliest stages of rheumatoid arthritis (RA). The migratory behavior and functional properties of GMC within the synovial tissue are, however, only incompletely characterized. Here we have analyzed GMC in the murine collagen-induced arthritis (CIA) model of RA using multi-photon real time in vivo microscopy together with ex vivo analysis of GMC in tissue sections. GMC were abundant as soon as clinical arthritis was apparent. GMC were motile and migrated randomly through the synovial tissue. In addition, we observed the frequent formation of cell clusters consisting of both neutrophilic granulocytes and monocytes that actively contributed to the inflammatory process of arthritis. Treatment of animals with a single dose of prednisolone reduced the mean velocity of cell migration and diminished the overall immigration of GMC. In summary, our study shows that the combined application of real time in vivo microscopy together with elaborate static post-mortem analysis of GMC enables the description of dynamic migratory characteristics of GMC together with their precise location in a complex anatomical environment. Moreover, this approach is sensitive enough to detect subtle therapeutic effects within a very short period of time.

Byrne, Ruth; Rath, Eva; Hladik, Anastasiya; Niederreiter, Birgit; Bonelli, Michael; Frantal, Sophie; Smolen, Josef S.; Scheinecker, Clemens

2012-01-01

117

Atypical Membrane Topology and Heteromeric Function of Drosophila Odorant Receptors In Vivo  

Microsoft Academic Search

Drosophila olfactory sensory neurons (OSNs) each express two odorant receptors (ORs): a divergent member of the OR family and the highly conserved, broadly expressed receptor OR83b. OR83b is essential for olfaction in vivo and enhances OR function in vitro, but the molecular mechanism by which it acts is unknown. Here we demonstrate that OR83b heterodimerizes with conventional ORs early in

Richard Benton; Silke Sachse; Stephen W. Michnick; Leslie B. Vosshall

2006-01-01

118

On-Chip In vivo Functional Imaging of the Mouse Brain Using a CMOS Image Sensor  

Microsoft Academic Search

We have developed a new method for in vivo functional imaging of the mouse brain using a dedicated CMOS image sensor chip. The image sensor has 176times144-pixels with pixel size of 7.5times7.5 mum 2. A novel packaging process is developed to enable on-chip fluorescence imaging. The sensor chip is attached to a flexible polyimide substrate and sealed in epoxy. A

D. C. Ng; T. Tokuda; K. Kagawa; H. Tamura; S. Shiosaka; J. Ohta

2006-01-01

119

GTP-binding proteins of the Rho/Rac family: regulation, effectors and functions in vivo  

PubMed Central

Summary Rho/Rac proteins constitute a subgroup of the Ras superfamily of GTP hydrolases. Although originally implicated in the control of cytoskeletal events, it is currently known that these GTPases coordinate diverse cellular functions, including cell polarity, vesicular trafficking, the cell cycle and transcriptomal dynamics. In this review, we will provide an overview on the recent advances in this field regarding the mechanism of regulation and signaling, and the roles in vivo of this important GTPase family.

Bustelo, Xose R.; Sauzeau, Vincent; Berenjeno, Inmaculada M.

2007-01-01

120

Skeletal muscle oxidative function in vivo and ex vivo in athletes with marked hypertrophy from resistance training.  

PubMed

Oxidative function during exercise was evaluated in 11 young athletes with marked skeletal muscle hypertrophy induced by long-term resistance training (RTA; body mass 102.6 ± 7.3 kg, mean ± SD) and 11 controls (CTRL; body mass 77.8 ± 6.0 kg). Pulmonary O2 uptake (Vo2) and vastus lateralis muscle fractional O2 extraction (by near-infrared spectroscopy) were determined during an incremental cycle ergometer (CE) and one-leg knee-extension (KE) exercise. Mitochondrial respiration was evaluated ex vivo by high-resolution respirometry in permeabilized vastus lateralis fibers obtained by biopsy. Quadriceps femoris muscle cross-sectional area, volume (determined by magnetic resonance imaging), and strength were greater in RTA vs. CTRL (by ?40%, ?33%, and ?20%, respectively). Vo2peak during CE was higher in RTA vs. CTRL (4.05 ± 0.64 vs. 3.56 ± 0.30 l/min); no difference between groups was observed during KE. The O2 cost of CE exercise was not different between groups. When divided per muscle mass (for CE) or quadriceps muscle mass (for KE), Vo2 peak was lower (by 15-20%) in RTA vs. CTRL. Vastus lateralis fractional O2 extraction was lower in RTA vs. CTRL at all work rates, during both CE and KE. RTA had higher ADP-stimulated mitochondrial respiration (56.7 ± 23.7 pmol O2·s(-1)·mg(-1) ww) vs. CTRL (35.7 ± 10.2 pmol O2·s(-1)·mg(-1) ww) and a tighter coupling of oxidative phosphorylation. In RTA, the greater muscle mass and maximal force and the enhanced mitochondrial respiration seem to compensate for the hypertrophy-induced impaired peripheral O2 diffusion. The net results are an enhanced whole body oxidative function at peak exercise and unchanged efficiency and O2 cost at submaximal exercise, despite a much greater body mass. PMID:23519233

Salvadego, Desy; Domenis, Rossana; Lazzer, Stefano; Porcelli, Simone; Rittweger, Jörn; Rizzo, Giovanna; Mavelli, Irene; Simunic, Bostjan; Pisot, Rado; Grassi, Bruno

2013-06-01

121

Limiting Dilution Analysis of Murine Epidermal Stem Cells Using an In Vivo Regeneration Assay  

PubMed Central

Summary Epidermal stem cells are of major importance for tissue homeostasis, wound repair, tumor initiation, and gene therapy. Here we describe an in vivo regeneration assay to test for the ability of keratinocyte progenitors to maintain an epidermis over the long term in vivo. Limiting dilution analysis of epidermal repopulating units in this in vivo regeneration assay at sequential time points allows the frequency of short term (transit amplifying cell) and long term (stem cell) repopulating cells to be quantified.

Strachan, Lauren R.; Ghadially, Ruby

2009-01-01

122

Direct link between RACK1 function and localization at the ribosome in vivo.  

PubMed

The receptor for activated C-kinase (RACK1), a conserved protein implicated in numerous signaling pathways, is a stoichiometric component of eukaryotic ribosomes located on the head of the 40S ribosomal subunit. To test the hypothesis that ribosome association is central to the function of RACK1 in vivo, we determined the 2.1-A crystal structure of RACK1 from Saccharomyces cerevisiae (Asc1p) and used it to design eight mutant versions of RACK1 to assess roles in ribosome binding and in vivo function. Conserved charged amino acids on one side of the beta-propeller structure were found to confer most of the 40S subunit binding affinity, whereas an adjacent conserved and structured loop had little effect on RACK1-ribosome association. Yeast mutations that confer moderate to strong defects in ribosome binding mimic some phenotypes of a RACK1 deletion strain, including increased sensitivity to drugs affecting cell wall biosynthesis and translation elongation. Furthermore, disruption of RACK1's position at the 40S ribosomal subunit results in the failure of the mRNA binding protein Scp160 to associate with actively translating ribosomes. These results provide the first direct evidence that RACK1 functions from the ribosome, implying a physical link between the eukaryotic ribosome and cell signaling pathways in vivo. PMID:19114558

Coyle, Scott M; Gilbert, Wendy V; Doudna, Jennifer A

2009-03-01

123

Functional Analysis of Bre1p, an E3 Ligase for Histone H2B Ubiquitylation, in Regulation of RNA Polymerase II Association with Active Genes and Transcription in Vivo*  

PubMed Central

H2B ubiquitylation is carried out by Bre1p, an E3 ligase, along with an E2 conjugase, Rad6p. H2B ubiquitylation has been previously implicated in promoting the association of RNA polymerase II with the coding sequence of the active GAL1 gene, and hence transcriptional elongation. Intriguingly, we find here that the association of RNA polymerase II with the active GAL1 coding sequence is not decreased in ?bre1, although it is required for H2B ubiquitylation. In contrast, the loss of Rad6p significantly impairs the association of RNA polymerase II with GAL1. Likewise, the point mutation of lysine 123 (ubiquitylation site) to arginine of H2B (H2B-K123R) also lowers the association of RNA polymerase II with GAL1, consistent with the role of H2B ubiquitylation in promoting RNA polymerase II association. Surprisingly, unlike the ?rad6 and H2B-K123R strains, complete deletion of BRE1 does not impair the association of RNA polymerase II with GAL1. However, deletion of the RING domain of Bre1p (that is essential for H2B ubiquitylation) impairs RNA polymerase II association with GAL1. These results imply that a non-RING domain of Bre1p counteracts the stimulatory role of the RING domain in regulating the association of RNA polymerase II with GAL1, and hence RNA polymerase II occupancy is not impaired in ?bre1. Consistently, GAL1 transcription is impaired in the absence of the RING domain of Bre1p, but not in ?bre1. Similar results are also obtained at other genes. Collectively, our results implicate both the stimulatory and repressive roles of Bre1p in regulation of RNA polymerase II association with active genes (and hence transcription) in vivo.

Sen, Rwik; Lahudkar, Shweta; Durairaj, Geetha; Bhaumik, Sukesh R.

2013-01-01

124

Analysis of the Ex Vivo and In Vivo Antiretroviral Activity of Gemcitabine  

PubMed Central

Replication of retroviral and host genomes requires ribonucleotide reductase to convert rNTPs to dNTPs, which are then used as substrates for DNA synthesis. Inhibition of ribonucleotide reductase by hydroxyurea (HU) has been previously used to treat cancers as well as HIV. However, the use of HU as an antiretroviral is limited by its associated toxicities such as myelosuppression and hepatotoxicity. In this study, we examined the ribonucleotide reductase inhibitor, gemcitabine, both in cell culture and in C57Bl/6 mice infected with LP-BM5 murine leukemia virus (LP-BM5 MuLV, a murine AIDS model). Gemcitabine decreased infectivity of MuLV in cell culture with an EC50 in the low nanomolar range with no detectable cytotoxicity. Similarly, gemcitabine significantly decreased disease progression in mice infected with LP-BM5. Specifically, gemcitabine treatment decreased spleen size, plasma IgM, and provirus levels compared to LP-BM5 MuLV infected, untreated mice. Gemcitabine efficacy was observed at doses as low as 1 mg/kg/day in the absence of toxicity. Higher doses of gemcitabine (3 mg/kg/day and higher) were associated with toxicity as determined by a loss in body mass. In summary, our findings demonstrate that gemcitabine has antiretroviral activity ex vivo and in vivo in the LP-BM5 MuLV model. These observations together with a recent ex vivo study with HIV-1[1], suggest that gemcitabine has broad antiretroviral activity and could be particularly useful in vivo when used in combination drug therapy.

Clouser, Christine L.; Holtz, Colleen M.; Mullett, Mary; Crankshaw, Duane L.; Briggs, Jacquie E.; Chauhan, Jay; VanHoutan, Ilze Matise; Patterson, Steven E.; Mansky, Louis M.

2011-01-01

125

Analysis of Chlamydomonas thiamin metabolism in vivo reveals riboswitch plasticity.  

PubMed

Thiamin (vitamin B1) is an essential micronutrient needed as a cofactor for many central metabolic enzymes. Animals must have thiamin in their diet, whereas bacteria, fungi, and plants can biosynthesize it de novo from the condensation of a thiazole and a pyrimidine moiety. Although the routes to biosynthesize these two heterocycles are not conserved in different organisms, in all cases exogenous thiamin represses expression of one or more of the biosynthetic pathway genes. One important mechanism for this control is via thiamin-pyrophosphate (TPP) riboswitches, regions of the mRNA to which TPP can bind directly, thus facilitating fine-tuning to maintain homeostasis. However, there is little information on how modulation of riboswitches affects thiamin metabolism in vivo. Here we use the green alga, Chlamydomonas reinhardtii, which regulates both thiazole and pyrimidine biosynthesis with riboswitches in the THI4 (Thiamin 4) and THIC (Thiamin C) genes, respectively, to investigate this question. Our study reveals that regulation of thiamin metabolism is not the simple dogma of negative feedback control. Specifically, balancing the provision of both of the heterocycles of TPP appears to be an important requirement. Furthermore, we show that the Chlamydomonas THIC riboswitch is controlled by hydroxymethylpyrimidine pyrophosphate, as well as TPP, but with an identical alternative splicing mechanism. Similarly, the THI4 gene is responsive to thiazole. The study not only provides insight into the plasticity of the TPP riboswitches but also shows that their maintenance is likely to be a consequence of evolutionary need as a function of the organisms' environment and the particular pathway used. PMID:23959877

Moulin, Michael; Nguyen, Ginnie T D T; Scaife, Mark A; Smith, Alison G; Fitzpatrick, Teresa B

2013-09-01

126

Ex vivo generation of a functional and regenerative wound epithelium from axolotl (Ambystoma mexicanum) skin.  

PubMed

Urodele amphibians (salamanders) are unique among adult vertebrates in their ability to regenerate structurally complete and fully functional limbs. Regeneration is a stepwise process that requires interactions between keratinocytes, nerves and fibroblasts. The formation of a wound epithelium covering the amputation site is an early and necessary event in the process but the molecular mechanisms that underlie the role of the wound epithelium in regeneration remain unclear. We have developed an ex vivo model that recapitulates many features of in vivo wound healing. The model comprises a circular explant of axolotl (Ambystoma mexicanum) limb skin with a central circular, full thickness wound. Re-epithelialization of the wound area is rapid (typically <11?h) and is dependent on metalloproteinase activity. The ex vivo wound epithelium is viable, responds to neuronal signals and is able to participate in ectopic blastema formation and limb regeneration. This ex vivo model provides a reproducible and tractable system in which to study the cellular and molecular events that underlie wound healing and regeneration. PMID:20874715

Ferris, Donald R; Satoh, Akira; Mandefro, Berhan; Cummings, Gillian M; Gardiner, David M; Rugg, Elizabeth L

2010-10-01

127

Mapping functional domains of chloride intracellular channel (CLIC) proteins in vivo.  

PubMed

Chloride intracellular channel (CLIC) proteins are small proteins distantly related to the omega family of glutathione S-transferases (GSTs). CLIC proteins are expressed in a wide variety of tissues in multicellular organisms and are targeted to specific cellular membranes. Members of this family are capable in vitro of changing conformation from a globular, soluble state to a membrane-inserted state in which they provide chloride conductance. The structural basis for in vivo CLIC protein function, however, is not well understood. We have mapped the functional domains of CLIC family members using an in vivo assay for membrane localization and function of CLIC proteins in the nematode Caenorhabditis elegans. A<70 amino acid N-terminal domain is a key determinant of membrane localization and function of invertebrate CLIC proteins. This domain, which we term the ''PTM'' domain, named after an amphipathic putative transmembrane helix contained within it, directs distinct C. elegans CLIC homologs to distinct subcellular membranes. We find that within the PTM region, the cysteine residues required for GST-type activity are unnecessary for invertebrate CLIC function, but that specific residues within the proposed transmembrane helix are necessary for correct targeting and protein function. We find that among all tested invertebrate CLIC proteins, function appears to be completely conserved despite striking differences in the charged residues contained within the amphipathic helix. This indicates that these residues do not contribute to anion selectivity as previously suggested. We find that outside the PTM region, the remaining three-quarters of CLIC protein sequence is functionally equivalent not only among vertebrate and invertebrate CLIC proteins, but also among the more distantly related GST-omega and GST-sigma proteins. The PTM region thus provides both targeting information and CLIC functional specificity, possibly adapting GST-type proteins to function as ion channels. PMID:16737711

Berry, Katherine L; Hobert, Oliver

2006-06-23

128

In vivo functional genomic studies of sterol carrier protein-2 gene in the yellow fever mosquito.  

PubMed

A simple and efficient DNA delivery method to introduce extrachromosomal DNA into mosquito embryos would significantly aid functional genomic studies. The conventional method for delivery of DNA into insects is to inject the DNA directly into the embryos. Taking advantage of the unique aspects of mosquito reproductive physiology during vitellogenesis and an in vivo transfection reagent that mediates DNA uptake in cells via endocytosis, we have developed a new method to introduce DNA into mosquito embryos vertically via microinjection of DNA vectors in vitellogenic females without directly manipulating the embryos. Our method was able to introduce inducible gene expression vectors transiently into F0 mosquitoes to perform functional studies in vivo without transgenic lines. The high efficiency of expression knockdown was reproducible with more than 70% of the F0 individuals showed sufficient gene expression suppression (<30% of the controls' levels). At the cohort level, AeSCP-2 expression knockdown in early instar larvae resulted in detectable phenotypes of the expression deficiency such as high mortality, lowered fertility, and distorted sex ratio after induction of AeSCP-2 siRNA expression in vivo. The results further confirmed the important role of AeSCP-2 in the development and reproduction of A. aegypti. In this study, we proved that extrachromosomal transient expression of an inducible gene from a DNA vector vertically delivered via vitellogenic females can be used to manipulate gene expression in F0 generation. This new method will be a simple and efficient tool for in vivo functional genomic studies in mosquitoes. PMID:21437205

Peng, Rong; Maklokova, Vilena I; Chandrashekhar, Jayadevi H; Lan, Que

2011-01-01

129

Functionalized near-infrared quantum dots for in vivo tumor vasculature imaging  

NASA Astrophysics Data System (ADS)

In this paper, we report the use of near-infrared (NIR)-emitting alloyed quantum dots (QDs) as efficient optical probes for high contrast in vivo imaging of tumors. Alloyed CdTe1 - xSex/CdS QDs were prepared in the non-aqueous phase using the hot colloidal synthesis approach. Water dispersion of the QDs were accomplished by their encapsulation within polyethyleneglycol (PEG)-grafted phospholipid micelles. For tumor-specific delivery in vivo, the micelle-encapsulated QDs were conjugated with the cyclic arginine-glycine-aspartic acid (cRGD) peptide, which targets the ?v?3 integrins overexpressed in the angiogenic tumor vasculatures. Using in vivo NIR optical imaging of mice bearing pancreatic cancer xenografts, implanted both subcutaneously and orthotopically, we have demonstrated that systemically delivered cRGD-conjugated QDs, but not the unconjugated ones, can efficiently target and label the tumors with high signal-to-noise ratio. Histopathological analysis of major organs of the treated mice showed no evidence of systemic toxicity associated with these QDs. These experiments suggest that cRGD-conjugated NIR QDs can serve as safe and efficient probes for optical bioimaging of tumors in vivo. Furthermore, by co-encapsulating these QDs and anticancer drugs within these micelles, we have demonstrated a promising theranostic, nanosized platform for both cancer imaging and therapy.

Hu, Rui; Yong, Ken-Tye; Roy, Indrajit; Ding, Hong; Law, Wing-Cheung; Cai, Hongxing; Zhang, Xihe; Vathy, Lisa A.; Bergey, Earl J.; Prasad, Paras N.

2010-04-01

130

On the origin and functions of the term functional analysis.  

PubMed

In this essay, we note that although Iwata, Dorsey, Slifer, Bauman, and Richman (1982) established the standard framework for conducting functional analyses of problem behavior, the term functional analysis was probably first used in behavior analysis by B. F. Skinner in 1948. We also remind readers that a functional analysis is really an experimental analysis, words that were contained in the title of Skinner's first book, The Behavior of Organisms: An Experimental Analysis (1938). We further describe how Skinner initially applied the concept of functional analysis to an understanding of verbal behavior, and we suggest that the same tactic be applied to the verbal behavior of behavior analysts, in the present case, to the term functional analysis. PMID:24114100

Schlinger, Henry D; Normand, Matthew P

2013-01-01

131

Environmentally persistent free radicals decrease cardiac function before and after ischemia/reperfusion injury in vivo  

PubMed Central

Exposure to airborne particles is associated with increased cardiovascular morbidity and mortality. During the combustion of chlorine-containing hazardous materials and fuels, chlorinated hydrocarbons chemisorb to the surface of transition metal-oxide-containing particles, reduce the metal, and form an organic free radical. These radical-particle systems can survive in the environment for days and are called environmentally persistent free radicals (EPFRs). This study determined whether EPFRs could decrease left ventricular function before and after ischemia and reperfusion (I/R) in vivo. Male Brown Norway rats were dosed (8 mg/kg, i.t.) 24 hr prior to testing with particles containing the EPFR of 1, 2-dichlorobenzene (DCB230). DCB230 treatment decreased systolic and diastolic function. DCB230 also produced pulmonary and cardiac inflammation. After ischemia, systolic, but not diastolic function was significantly decreased in DCB230-treated rats. Ventricular function was not affected by I/R in control rats. There was greater oxidative stress in the heart and increased 8-isoprostane (biomarker of oxidative stress) in the plasma of treated vs control rats after I/R. These data demonstrate for the first time that DCB230 can produce inflammation and significantly decrease cardiac function at baseline and after I/R in vivo. Furthermore, these data suggest that EPFRs may be a risk factor for cardiac toxicity in healthy individuals and individuals with ischemic heart disease. Potential mechanisms involving cytokines/chemokines and/or oxidative stress are discussed.

Lord, Kevin; Moll, David; Lindsey, John K.; Mahne, Sarah; Raman, Girija; Dugas, Tammy; Cormier, Stephania; Troxlair, Dana; Lomnicki, Slawo; Dellinger, Barry; Varner, Kurt

2011-01-01

132

Fluorescent function-spacer-lipid construct labelling allows for real-time in vivo imaging of cell migration and behaviour in zebrafish (Danio rerio).  

PubMed

Real-time in vivo imaging of cell migration and behavior has advanced our understanding of physiological processes in situ, especially in the field of immunology. We carried out the transplantation of a mixed population of blood cells from adult zebrafish (Danio rerio) to 2 day old embryos. The blood cells were treated ex vivo with Function-Spacer-Lipid constructs (FSL) incorporating either fluorescein or Atto488 fluorophores (FSL-FLRO4-I or -II). Excellent labeling efficiency was demonstrated by epifluorescence microscopy and FACScan analysis. Real-time video imaging of the recipient fish showed that the functionality of these cells was retained and not affected by the labeling. The usefulness of FSL-FLRO4-I as a contrast agent in microangiography was explored. Overall, we found both FSL-FLRO4-I and-II promising labeling dyes for real-time in vivo imaging in zebrafish. PMID:22434405

Lan, Chuan-Ching; Blake, Deborah; Henry, Stephen; Love, Donald R

2012-07-01

133

In vivo presynaptic and postsynaptic striatal dopamine functions in idiopathic normal pressure hydrocephalus.  

PubMed

Differentiation of impaired gait seen in idiopathic normal pressure hydrocephalus (iNPH) from parkinsonian gait is sometimes a great challenge and important for future medication in the clinical setting. To investigate dopaminergic contribution to its pathophysiology, two aspects of the trans-synaptic dopamine functions in the striatal region in eight iNPH patients naïve to dopaminergic drugs were examined using positron emission tomography with a presynaptic marker [11C]CFT ([11C]2-beta-carbomethoxy-3beta-(4-fluorophenyl) tropane) that binds to dopamine transporter and a postsynaptic marker [11C]raclopride that binds to D2 receptor. Quantitative values of binding potentials (BPs) for [11C]CFT and [11C]raclopride were compared between patients and eight age-matched healthy subjects. The BPs and magnetic resonance imaging-based morphometric measures in iNPH were used for correlation analyses between the magnitude of binding of these in vivo markers and clinical severity of the patients. Analysis of variance showed significant reduction in [11C]raclopride binding in the putamen and nucleus accumbens (P<0.05, corrected for multiple comparison) and unchanged striatal [11C]CFT binding in iNPH. The dorsal putamen [11C]raclopride binding correlated negatively with gait severity (r=0.720, P<0.05), and the nucleus accumbens [11C]raclopride binding correlated positively with emotional recognition score (r=0.727, P<0.05) in the disease group. No significant relationship was observed between BPs and morphometric measures. The current result of the postsynaptic D2 receptor reduction along with preserved presynaptic activity in the nigrostriatal dopaminergic system reflects a pathophysiology of iNPH. Postsynaptic D2 receptor hypoactivity in the dorsal putamen may predict the severity of gait impairment in iNPH. PMID:16926840

Ouchi, Yasuomi; Nakayama, Teiji; Kanno, Toshihiko; Yoshikawa, Etsuji; Shinke, Tomomi; Torizuka, Tatsuo

2007-04-01

134

Hepatitis C virus-infected cells downregulate NKp30 and inhibit ex vivo NK cell functions.  

PubMed

Hepatitis C virus (HCV) successfully evades the immune system and establishes chronic infection in ?80% of cases. Immune evasion may involve modulating NK cell functions. Therefore, we developed a short-term assay to assess immediate effects of HCV-infected cells on ex vivo NK cytotoxicity and cytokine production. Natural cytotoxicity, Ab-dependent cell-mediated cytotoxicity, IFN-? production, and TNF-? production were all significantly inhibited by short-term direct exposure to HCV-infected hepatoma-derived Huh-7.5 cells. Inhibition required cell-to-cell contact and increased together with multiplicity of infection and HCV protein levels. Blocking potential interaction between HCV E2 and NK CD81 did not abrogate NK cell inhibition mediated by HCV-infected cells. We observed no change in expression levels of NKG2D, NKG2A, NKp46, or CD16 on NK cells exposed to HCV-infected Huh-7.5 cells for 5 h or of human histocompatibility-linked leukocyte Ag E on HCV-infected compared with uninfected Huh-7.5 cells. Inhibition of ex vivo NK functions did correspond with reduced surface expression of the natural cytotoxicity receptor NKp30, and downregulation of NKp30 was functionally reflected in reduced anti-NKp30 redirected lysis of P815 cells. Infection of Huh-7.5 cells with HCV JFH1(T) increased surface binding of an NKp30-IgG1 Fc? fusion protein, suggesting upregulation of an antagonistic NKp30 ligand on HCV-infected cells. Our assay demonstrates rapid inhibition of critical NK cell functions by HCV-infected cells. Similar localized effects in vivo may contribute to establishment of chronic HCV infection and associated phenotypic and functional changes in the NK population. PMID:23960237

Holder, Kayla A; Stapleton, Staci N; Gallant, Maureen E; Russell, Rodney S; Grant, Michael D

2013-09-15

135

IN VIVO Function of Rare G6pd Variants from Natural Populations of DROSOPHILA MELANOGASTER  

PubMed Central

From 1981 to 1983, 15,097 X-chromosomes were genetically extracted from a number of North American populations of D. melanogaster and were electrophoretically screened for rare mobility and activity variants of glucose-6-phosphate dehydrogenase (G6PD). Overall, 13 rare variants were recovered for a frequency of about 10-3. Eleven variants affect electrophoretic mobility and are apparently structural, and two variants exhibit low G6PD activity. One low activity variant is closely associated with a P-element insertion at 18D12-13—all of the variants were subjected to the previously described genetic scheme used to identify relative in vivo activity differences between the two common electrophoretic variants associated with the global polymorphism. Most of the rare variants exhibit apparent in vivo activities that are similar to one or the other of the common variants, and these specific rare variants appear to be geographically widespread. Several variants have significantly reduced function. All of the variants were measured for larval specific activity for G6PD as a first measure of in vitro activity. It appears that specific activity alone is not a sufficient predictor for G6PD in vivo function.

Eanes, Walter F.; Hey, Jody

1986-01-01

136

Dynamic contrast-enhanced optical imaging of in vivo organ function  

PubMed Central

Abstract. Conventional approaches to optical small animal molecular imaging suffer from poor resolution, limited sensitivity, and unreliable quantitation, often reducing their utility in practice. We previously demonstrated that the in vivo dynamics of an injected contrast agent could be exploited to provide high-contrast anatomical registration, owing to the temporal differences in each organ’s response to the circulating fluorophore. This study extends this approach to explore whether dynamic contrast-enhanced optical imaging (DyCE) can allow noninvasive, in vivo assessment of organ function by quantifying the differing cellular uptake or wash-out dynamics of an agent in healthy and damaged organs. Specifically, we used DyCE to visualize and measure the organ-specific uptake dynamics of indocyanine green before and after induction of transient liver damage. DyCE imaging was performed longitudinally over nine days, and blood samples collected at each imaging session were analyzed for alanine aminotransferase (ALT), a liver enzyme assessed clinically as a measure of liver damage. We show that changes in DyCE-derived dynamics of liver and kidney dye uptake caused by liver damage correlate linearly with ALT concentrations, with an r2 value of 0.91. Our results demonstrate that DyCE can provide quantitative, in vivo, longitudinal measures of organ function with inexpensive and simple data acquisition.

Amoozegar, Cyrus B.; Wang, Tracy; Bouchard, Matthew B.; McCaslin, Addason F. H.; Blaner, William S.; Levenson, Richard M.; Hillman, Elizabeth M. C.

2012-01-01

137

Functional Analysis and Treatment of Nail Biting  

ERIC Educational Resources Information Center

This study applied functional analysis methodology to nail biting exhibited by a 24-year-old female graduate student. Results from the brief functional analysis indicated variability in nail biting across assessment conditions. Functional analysis data were then used to guide treatment development and implementation. Treatment included a…

Dufrene, Brad A.; Watson, T. Steuart; Kazmerski, Jennifer S.

2008-01-01

138

Functional characterization of equine neutrophils in response to calcium ionophore A23187 and phorbol myristate acetate ex vivo  

Microsoft Academic Search

Equine neutrophils (PMN) play a critical role in inflammatory processes in horses. The objective of this study was to characterize equine PMN function ex vivo following stimulation with calcium ionophore A23187 (A23187) and phorbol myristate acetate (PMA). These stimulants trigger different branches of the PMN activation process that occurs in vivo. Equine PMN were isolated from the whole blood of

T. Moore; J. Wilcke; C. Chilcoat; P. Eyre; M. Crisman

1997-01-01

139

Rapid semi-automated segmentation and analysis of neuronal morphology and function from confocal image data  

Microsoft Academic Search

Confocal microscopy combined with cellular labeling techniques can be an effective method for imaging the morphology of a cell as well as various functional characteristics in vivo. Current analysis methods are manual, and therefore, time-consuming and prone to error. Through the development of custom algorithms and application design, the analysis process can be improved to decrease analysis time and increase

David R. Holmes III; M. J. Moore; C. B. Mantilla; Gary C Sieck; Richard A. Robb

2002-01-01

140

Functional Cooperation of the Proapoptotic Bcl2 Family Proteins Bmf and Bim In Vivo ?  

PubMed Central

Bcl2-modifying factor (Bmf) is a member of the BH3-only group of proapoptotic proteins. To test the role of Bmf in vivo, we constructed mice with a series of mutated Bmf alleles that disrupt Bmf expression, prevent Bmf phosphorylation by the c-Jun NH2-terminal kinase (JNK) on Ser74, or mimic Bmf phosphorylation on Ser74. We report that the loss of Bmf causes defects in uterovaginal development, including an imperforate vagina and hydrometrocolpos. We also show that the phosphorylation of Bmf on Ser74 can contribute to a moderate increase in levels of Bmf activity. Studies of compound mutants with the related gene Bim demonstrated that Bim and Bmf exhibit partially redundant functions in vivo. Thus, developmental ablation of interdigital webbing on mouse paws and normal lymphocyte homeostasis require the cooperative activity of Bim and Bmf.

Hubner, Anette; Cavanagh-Kyros, Julie; Rincon, Mercedes; Flavell, Richard A.; Davis, Roger J.

2010-01-01

141

Functional cooperation of the proapoptotic Bcl2 family proteins Bmf and Bim in vivo.  

PubMed

Bcl2-modifying factor (Bmf) is a member of the BH3-only group of proapoptotic proteins. To test the role of Bmf in vivo, we constructed mice with a series of mutated Bmf alleles that disrupt Bmf expression, prevent Bmf phosphorylation by the c-Jun NH(2)-terminal kinase (JNK) on Ser(74), or mimic Bmf phosphorylation on Ser(74). We report that the loss of Bmf causes defects in uterovaginal development, including an imperforate vagina and hydrometrocolpos. We also show that the phosphorylation of Bmf on Ser(74) can contribute to a moderate increase in levels of Bmf activity. Studies of compound mutants with the related gene Bim demonstrated that Bim and Bmf exhibit partially redundant functions in vivo. Thus, developmental ablation of interdigital webbing on mouse paws and normal lymphocyte homeostasis require the cooperative activity of Bim and Bmf. PMID:19841067

Hübner, Anette; Cavanagh-Kyros, Julie; Rincon, Mercedes; Flavell, Richard A; Davis, Roger J

2010-01-01

142

An in vivo analysis of the localisation and interactions of human p66 DNA polymerase ? subunit  

PubMed Central

Background DNA polymerase ? is essential for eukaryotic DNA replication and also plays a role in DNA repair. The processivity of this polymerase complex is dependent upon its interaction with the sliding clamp PCNA and the polymerase-PCNA interaction is largely mediated through the p66 polymerase subunit. We have analysed the interactions of the human p66 DNA polymerase ? subunit with PCNA and with components of the DNA polymerase ? complex in vivo. Results Using the two-hybrid system, we have mapped the interaction domains for binding to the p50 polymerase ? subunit and with PCNA to the N-terminus and the C-terminus of p66, respectively. Co-immunoprecipitation experiments confirm that these interaction domains are functional in vivo. Expression of EGFP-p66 shows that it is a nuclear protein which co-localises with PCNA throughout the cell cycle. p66 is localised to sites of DNA replication during S phase and to repair foci following DNA damage. We have identified a functional nuclear localisation sequence and shown that localisation to replication foci is not dependent upon active nuclear import. Sub-domains of p66 act as dominant negative suppressors of colony formation, suggesting that p66 forms an essential structural link between the p50 subunit and PCNA. Analysis of the C-terminal PCNA binding motif shows that deletion of the QVSITGFF core motif results in a reduced affinity for PCNA, while deletion of a further 20 amino acids completely abolishes the interaction. A reduced affinity for PCNA correlates with reduced targeting to replication foci. We have confirmed the p66-PCNA interaction in vivo using fluorescence resonance energy transfer (FRET) techniques. Conclusion We have defined the regions of p66 required for its interaction with PCNA and the p50 polymerase subunit. We demonstrate a functional link between PCNA interaction and localisation to replication foci and show that there is a direct interaction between p66 and PCNA in living cells during DNA replication. The dominant negative effect upon growth resulting from expression of p66 sub-domains confirms that the p66-PCNA interaction is essential in vivo.

Pohler, J Richard G; Otterlei, Marit; Warbrick, Emma

2005-01-01

143

The Rap1 GTPase functions as a regulator of morphogenesis in vivo.  

PubMed Central

The Ras-related Rap GTPases are highly conserved across diverse species but their normal biological function is not well understood. Initial studies in mammalian cells suggested a role for Rap as a Ras antagonist. More recent experiments indicate functions in calcium- and cAMP-mediated signaling and it has been proposed that protein kinase A-mediated phosphorylation activates Rap in vivo. We show that Ras1-mediated signaling pathways in Drosophila are not influenced by Rap1 levels, suggesting that Ras1 and Rap1 function via distinct pathways. Moreover, a mutation that abolishes the putative cAMP-dependent kinase phosphorylation site of Drosophila Rap1 can still rescue the Rap1 mutant phenotype. Our experiments show that Rap1 is not needed for cell proliferation and cell-fate specification but demonstrate a critical function for Rap1 in regulating normal morphogenesis in the eye disk, the ovary and the embryo. Rap1 mutations also disrupt cell migrations and cause abnormalities in cell shape. These findings indicate a role for Rap proteins as regulators of morphogenesis in vivo.

Asha, H; de Ruiter, N D; Wang, M G; Hariharan, I K

1999-01-01

144

Critical Role of Tissue Mast Cells in Controlling Long Term Glucose Sensor Function in Vivo  

PubMed Central

Little is known about the specific cells, mediators and mechanisms involved in the loss of glucose sensor function (GSF) in vivo. Since mast cells (MC) are known to be key effector cells in inflammation and wound healing, we hypothesized that MC and their products are major contributors to the skin inflammation and wound healing that controls GSF at sites of sensor implantation. To test this hypothesis we utilized a murine model of continuous glucose monitoring (CGM) in vivo in both normal C57BL/6 mice (mast cell sufficient), as well as mast cell deficient B6.Cg-KitW-sh/HNihrJaeBsmJ (Sash) mice over a 28 day CGM period. As expected, both strains of mice displayed excellent CGM for the first 7 days post sensor implantation (PSI). CGM in the mast cell sufficient C57BL/6 mice was erratic over the remaining 21 days PSI. CGM in the mast cell deficient Sash mice displayed excellent sensor function for the entire 28 day of CGM. Histopathologic evaluation of implantation sites demonstrated that tissue reactions in Sash mice were dramatically less compared to the reactions in normal C57BL/6 mice. Additionally, mast cells were also seen to be consistently associated with the margins of sensor tissue reactions in normal C57BL/6 mice. Finally, direct injection of bone marrow derived mast cells at sites of sensor implantation induced an acute and dramatic loss of sensor function in both C57BL/6 and Sash mice. These results demonstrate the key role of mast cells in controlling glucose sensor function in vivo.

Klueh, Ulrike; Kaur, Manjot; Qiao, Yi; Kreutzer, Donald L.

2010-01-01

145

Nonsmooth Analysis of Spectral Functions1  

Microsoft Academic Search

Any spectral function can be written as a composition function of a symmetric function f :I R n 7! IR and the eigenvalue function ( ): S7 !IR n, often denoted by (f ). S is the subspace of n n symmetric matrices. In this paper, we present some nonsmooth analysis to such spectral functions. Our main results are: (a)

Houduo Qi; Xiaoqi Yang

2002-01-01

146

PEG-Mediated Synthesis of Highly Dispersive Multifunctional Superparamagnetic Nanoparticles: Their Physicochemical Properties and Function In Vivo  

PubMed Central

Multifunctional superparamagnetic nanoparticles have been developed for a wide range of applications in nanomedicine, such as serving as tumor targeted drug carriers and molecular imaging agents. To function in vivo, the development of these novel materials must overcome several challenging requirements including biocompatibility, stability in physiological solutions, non-toxicity and the ability to traverse biological barriers. Here we report a PEG-mediated synthesis process to produce well-dispersed, ultrafine, and highly stable iron oxide nanoparticles for in vivo applications. Utilizing a biocompatible PEG coating bearing amine functional groups, the produced nanoparticles serve as an effective platform with the ability to incorporate a variety of targeting, therapeutic or imaging ligands. In this study, we demonstrated tumor-specific accumulation of these nanoparticles through both magnetic resonance and optical imaging after conjugation with chlorotoxin, a peptide with high affinity toward tumors of the neuroectodermal origin, and Cy5.5, a near-infrared fluorescent dye. Furthermore, we performed preliminary biodistribution and toxicity assessments of these nanoparticles in wild-type mice through histological analysis of clearance organs and hematology assay, and the results demonstrated the relative biocompatibility of these nanoparticles.

Sun, Conroy; Du, Kim; Fang, Chen; Bhattarai, Narayan; Veiseh, Omid; Kivit, Forrest; Stephen, Zachary; Lee, Donghoon; Ellenbogen, Richard G.; Ratner, Buddy; Zhang, Miqin

2010-01-01

147

Differential Item Functioning Analysis Using Rasch Item Information Functions  

ERIC Educational Resources Information Center

Differential item functioning (DIF) analysis is a statistical technique used for ensuring the equity and fairness of educational assessments. This study formulates a new DIF analysis method using the information similarity index (ISI). ISI compares item information functions when data fits the Rasch model. Through simulations and an international…

Wyse, Adam E.; Mapuranga, Raymond

2009-01-01

148

Functional optical coherence tomography to reveal functional architecture of cat visual cortex in vivo  

NASA Astrophysics Data System (ADS)

Optical intrinsic signal imaging (OISI) provides the surface activation map of brain and has provided many insights. In this study, we show that the optical coherence tomography (OCT) can indeed provide depth resolved functional map of cat visual cortex. Activation profile obtained by integrating OCT signal across depth correlates well with that determined by the OISI. Functional OCT (fOCT) promises to be a valid technique for revealing unexplored organization inside the brain at a micro system level.

Homma, Ryota; Kadono, Hirofumi; Tanifuji, Manabu; Uma Maheswari, Rajagopalan

2003-10-01

149

Mathematical modeling and analysis of insulin clearance in vivo  

Microsoft Academic Search

BACKGROUND: Analyzing the dynamics of insulin concentration in the blood is necessary for a comprehensive understanding of the effects of insulin in vivo. Insulin removal from the blood has been addressed in many studies. The results are highly variable with respect to insulin clearance and the relative contributions of hepatic and renal insulin degradation. RESULTS: We present a dynamic mathematical

Markus Koschorreck; Ernst Dieter Gilles

2008-01-01

150

Analysis of the mutations inducedd by conazole fungicides in vivo  

EPA Science Inventory

The mouse liver tumorigenic conazo1e fungicides triadimefon and propiconazo1e have previously been shown to be in vivo mouse liver mutagens in the Big Blue" transgenic mutation assay when administered in feed at tumorigenic doses, whereas the nontumorigenic conazo1e myc1obutani1 ...

151

Mathematical Analysis Of Hiv1 Dynamics In Vivo  

Microsoft Academic Search

. Mathematical models have proven valuable in understanding the dynamics of HIV-1infection in vivo. By comparing these models to data obtained from patients undergoing antiretroviraldrug therapy, it has been possible to determine many quantitative features of the interaction betweenHIV-1, the virus that causes AIDS, and the cells that are infected by the virus. The most dramaticfinding has been that even

Alan S. Perelson; Patrick W. Nelson

1998-01-01

152

Biomechanical regulation of vascular smooth muscle cell functions: from in vitro to in vivo understanding  

PubMed Central

Vascular smooth muscle cells (VSMCs) have critical functions in vascular diseases. Haemodynamic factors are important regulators of VSMC functions in vascular pathophysiology. VSMCs are physiologically active in the three-dimensional matrix and interact with the shear stress sensor of endothelial cells (ECs). The purpose of this review is to illustrate how haemodynamic factors regulate VSMC functions under two-dimensional conditions in vitro or three-dimensional co-culture conditions in vivo. Recent advances show that high shear stress induces VSMC apoptosis through endothelial-released nitric oxide and low shear stress upregulates VSMC proliferation and migration through platelet-derived growth factor released by ECs. This differential regulation emphasizes the need to construct more actual environments for future research on vascular diseases (such as atherosclerosis and hypertension) and cardiovascular tissue engineering.

Qiu, Juhui; Zheng, Yiming; Hu, Jianjun; Liao, Donghua; Gregersen, Hans; Deng, Xiaoyan; Fan, Yubo; Wang, Guixue

2014-01-01

153

Simultaneous functional photoacoustic and ultrasonic endoscopy of internal organs in vivo  

PubMed Central

Presently, clinicians routinely apply ultrasound endoscopy in a variety of interventional procedures which provide treatment solutions for diseased organs. Ultrasound endoscopy not only produces high resolution images, it is also safe for clinical use and broadly applicable. However, for soft tissue imaging, its mechanical wave-based image contrast fundamentally limits its ability to provide physiologically-specific functional information. By contrast, photoacoustic endoscopy possesses a unique combination of functional optical contrast and high spatial resolution at clinically-relevant depths, ideal for soft tissue imaging. With these attributes, photoacoustic endoscopy can overcome the current limitations of ultrasound endoscopy. Moreover, the benefits of photoacoustic imaging do not come at the expense of existing ultrasound functions; photoacoustic endoscopy systems are inherently compatible with ultrasound imaging, enabling multi-modality imaging with complementary contrast. Here, we present simultaneous photoacoustic and ultrasonic dual-mode endoscopy and demonstrate its ability to image internal organs in vivo, illustrating its potential clinical application.

Yang, Joon-Mo; Favazza, Christopher; Chen, Ruimin; Yao, Junjie; Cai, Xin; Maslov, Konstantin; Zhou, Qifa; Shung, K. Kirk; Wang, Lihong V.

2013-01-01

154

Biomechanical regulation of vascular smooth muscle cell functions: from in vitro to in vivo understanding.  

PubMed

Vascular smooth muscle cells (VSMCs) have critical functions in vascular diseases. Haemodynamic factors are important regulators of VSMC functions in vascular pathophysiology. VSMCs are physiologically active in the three-dimensional matrix and interact with the shear stress sensor of endothelial cells (ECs). The purpose of this review is to illustrate how haemodynamic factors regulate VSMC functions under two-dimensional conditions in vitro or three-dimensional co-culture conditions in vivo. Recent advances show that high shear stress induces VSMC apoptosis through endothelial-released nitric oxide and low shear stress upregulates VSMC proliferation and migration through platelet-derived growth factor released by ECs. This differential regulation emphasizes the need to construct more actual environments for future research on vascular diseases (such as atherosclerosis and hypertension) and cardiovascular tissue engineering. PMID:24152813

Qiu, Juhui; Zheng, Yiming; Hu, Jianjun; Liao, Donghua; Gregersen, Hans; Deng, Xiaoyan; Fan, Yubo; Wang, Guixue

2014-01-01

155

Functional evaluation of malaria Pfs25 DNA vaccine by in vivo electroporation in Olive baboons  

PubMed Central

Plasmodium falciparum Pfs25 antigen, expressed on the surface of zygotes and ookinetes, is one of the leading targets for the development of a malaria transmission-blocking vaccine (TBV). Our laboratory has been evaluating DNA plasmid based Pfs25 vaccine in mice and non-human primates. Previously, we established that in vivo electroporation (EP) delivery is an effective method to improve the immunogenicity of DNA vaccine encoding Pfs25 in mice. In order to optimize the in vivo EP procedure and test for its efficacy in more clinically relevant larger animal models, we employed in vivo EP to evaluate the immune response and protective efficacy of Pfs25 encoding DNA vaccine in nonhuman primates (Olive baboons, Papio anubis). The results showed that at a dose of 2.5 mg DNA vaccine, antibody responses were significantly enhanced with EP as compared to without EP resulting in effective transmission blocking efficiency. Similar immunogenicity enhancing effect of EP was also observed with lower doses (0.5 mg and 1 mg) of DNA plasmids. Further, final boosting with a single dose of recombinant Pfs25 protein resulted in dramatically enhanced antibody titers and significantly increased functional transmission blocking efficiency. Our study suggests priming with DNA vaccine via EP along with protein boost regimen as an effective method to elicit potent immunogenicity of malaria DNA vaccines in nonhuman primates and provides the basis for further evaluation in human volunteers.

Kumar, Rajesh; Nyakundi, Ruth; Kariuki, Thomas; Ozwara, Hastings; Nyamongo, Onkoba; Mlambo, Godfree; Ellefsen, Barry; Hannaman, Drew; Kumar, Nirbhay

2013-01-01

156

Functional evaluation of malaria Pfs25 DNA vaccine by in vivo electroporation in olive baboons.  

PubMed

Plasmodium falciparum Pfs25 antigen, expressed on the surface of zygotes and ookinetes, is one of the leading targets for the development of a malaria transmission-blocking vaccine (TBV). Our laboratory has been evaluating DNA plasmid based Pfs25 vaccine in mice and non-human primates. Previously, we established that in vivo electroporation (EP) delivery is an effective method to improve the immunogenicity of DNA vaccine encoding Pfs25 in mice. In order to optimize the in vivo EP procedure and test for its efficacy in more clinically relevant larger animal models, we employed in vivo EP to evaluate the immune response and protective efficacy of Pfs25 encoding DNA vaccine in nonhuman primates (olive baboons, Papio anubis). The results showed that at a dose of 2.5mg DNA vaccine, antibody responses were significantly enhanced with EP as compared to without EP resulting in effective transmission blocking efficiency. Similar immunogenicity enhancing effect of EP was also observed with lower doses (0.5mg and 1mg) of DNA plasmids. Further, final boosting with a single dose of recombinant Pfs25 protein resulted in dramatically enhanced antibody titers and significantly increased functional transmission blocking efficiency. Our study suggests priming with DNA vaccine via EP along with protein boost regimen as an effective method to elicit potent immunogenicity of malaria DNA vaccines in nonhuman primates and provides the basis for further evaluation in human volunteers. PMID:23684840

Kumar, Rajesh; Nyakundi, Ruth; Kariuki, Thomas; Ozwara, Hastings; Nyamongo, Onkoba; Mlambo, Godfree; Ellefsen, Barry; Hannaman, Drew; Kumar, Nirbhay

2013-06-28

157

Functional Analysis of Transcription Factors in Arabidopsis  

PubMed Central

Transcription factors (TFs) regulate the expression of genes at the transcriptional level. Modification of TF activity dynamically alters the transcriptome, which leads to metabolic and phenotypic changes. Thus, functional analysis of TFs using ‘omics-based’ methodologies is one of the most important areas of the post-genome era. In this mini-review, we present an overview of Arabidopsis TFs and introduce strategies for the functional analysis of plant TFs, which include both traditional and recently developed technologies. These strategies can be assigned to five categories: bioinformatic analysis; analysis of molecular function; expression analysis; phenotype analysis; and network analysis for the description of entire transcriptional regulatory networks.

Mitsuda, Nobutaka; Ohme-Takagi, Masaru

2009-01-01

158

Neurofibrillary tangle-bearing neurons are functionally integrated in cortical circuits in vivo.  

PubMed

Alzheimer's disease (AD) is pathologically characterized by the deposition of extracellular amyloid-? plaques and intracellular aggregation of tau protein in neurofibrillary tangles (NFTs) (1, 2). Progression of NFT pathology is closely correlated with both increased neurodegeneration and cognitive decline in AD (3) and other tauopathies, such as frontotemporal dementia (4, 5). The assumption that mislocalization of tau into the somatodendritic compartment (6) and accumulation of fibrillar aggregates in NFTs mediates neurodegeneration underlies most current therapeutic strategies aimed at preventing NFT formation or disrupting existing NFTs (7, 8). Although several disease-associated mutations cause both aggregation of tau and neurodegeneration, whether NFTs per se contribute to neuronal and network dysfunction in vivo is unknown (9). Here we used awake in vivo two-photon calcium imaging to monitor neuronal function in adult rTg4510 mice that overexpress a human mutant form of tau (P301L) and develop cortical NFTs by the age of 7-8 mo (10). Unexpectedly, NFT-bearing neurons in the visual cortex appeared to be completely functionally intact, to be capable of integrating dendritic inputs and effectively encoding orientation and direction selectivity, and to have a stable baseline resting calcium level. These results suggest a reevaluation of the common assumption that insoluble tau aggregates are sufficient to disrupt neuronal function. PMID:24368848

Kuchibhotla, Kishore V; Wegmann, Susanne; Kopeikina, Katherine J; Hawkes, Jonathan; Rudinskiy, Nikita; Andermann, Mark L; Spires-Jones, Tara L; Bacskai, Brian J; Hyman, Bradley T

2014-01-01

159

Genome-wide location analysis by pull down of in vivo biotinylated transcription factors.  

PubMed

Recent development of methods for genome-wide identification of transcription factor binding sites by chromatin immunoprecipitation (ChIP) has led to novel insights into transcriptional regulation and greater understanding of the function of individual transcription factors. ChIP requires highly specific antibody against the transcriptional regulator of interest, and availability of suitable antibodies is a significant impediment to broader application of this approach. This limitation can be circumvented by tagging the transcriptional regulator of interest with a short bio epitope which is specifically biotinylated by the E. coli enzyme BirA. The biotinylated transcription factor can then be selectively pulled down on streptavidin beads under stringent conditions. This unit provides a detailed protocol for genome-wide location analysis of in vivo biotinylated transcription factors by streptavidin pull-down followed by high-throughput sequencing (bioChIP-seq). PMID:20890903

He, Aibin; Pu, William T

2010-10-01

160

In Vivo Evaluation of Vena Caval Filters: Can Function Be Linked to Design Characteristics?  

Microsoft Academic Search

Purpose: To compare the five vena caval filters marketed in the United States and one investigational vena caval filter and to determine\\u000a whether there is an association between their design and their in vivo function.\\u000a \\u000a \\u000a \\u000a \\u000a Methods: Four of each type of filter—Simon Nitinol (SN), Bird's Nest (BN), Vena Tech (VT), Greenfield stainless steel (PSGF), Greenfield\\u000a titanium (TGF), and the investigational

Mary C. Proctor; Kyung J. Cho; Lazar J. Greenfield

2000-01-01

161

Photoacoustics and fluorescence based nanoprobes towards functional and structural imaging in vivo  

NASA Astrophysics Data System (ADS)

Imaging of chemical analytes and structural properties related to physiological activities within biological systems is of great bio-medical interest; it can contribute to the fundamental understanding of biological systems and can be applied to the diagnosis and prognosis of diseases, especially tumors. The work presented in this thesis focuses on the development and application of polymeric nanoprobe aided optical imaging of chemical analytes (Oxygen, pH) and structural properties in live cells and animal models. To this end, specific nanoprobes, based on the polyacrylamide nanoplatform, bearing both appropriate targeting functionalities, and high concentrations of sensing and contrast agents, have been developed. The nanoprobes presented here are biodegradable, biocompatible and non-toxic, rendering them safe for in vivo use. Furthermore the nanoprobes are designed to have variable optical properties that are dependent on the local concentration of the specific analyte of interest. Optical imaging techniques that are particularly suited for deep tissue applications, such as two-photon fluorescence and photoacoustics, were applied for non-invasive real-time imaging and sensing in cancer cells, tumor spheroids and animal models. Our results demonstrate that this technique enables high sensitive detection of chemical analytes with a sensitivity of <5 Torr for oxygen and <0.1 pH units in vivo, which is better than the currently available in vivo functional imaging techniques. This non-invasive and non-ionizing, yet low cost, method will enable morphological and functional evaluation across any tissue, with both high spatial and temporal resolution but without eliciting short- or long-term tissue damage. Currently no gold standard exists for such xii functional imaging. The approach presented here can be used for early detection and diagnosis of tumors, as well as for monitoring the progression of disease and therapy. This technique will also enable observing phenomena at the cellular level in vivo that would lead to a better understanding of the pathophysiology of diseases as well as the disease onset, progression, and response to therapy.

Ray, Aniruddha

162

Hippocampal shape analysis in Alzheimer's disease using functional data analysis.  

PubMed

The hippocampus is one of the first affected regions in Alzheimer's disease. The left hippocampi of control subjects, patients with mild cognitive impairment and patients with Alzheimer's disease are represented by spherical harmonics. Functional data analysis is used in the hippocampal shape analysis. Functional principal component analysis and functional independent component analysis are defined for multivariate functions with two arguments. A functional linear discriminant function is also defined. Comparisons with other approaches are carried out. Our functional approach gives promising results, especially in shape classification. Copyright © 2013 John Wiley & Sons, Ltd. PMID:24105806

Epifanio, Irene; Ventura-Campos, Noelia

2014-02-28

163

Vivo-Morpholino knockdown of alphaIIb: A novel approach to inhibit thrombocyte function in adult zebrafish.  

PubMed

Knockdown of protein function by antisense oligonucleotides has been used to understand the protein function not only in development but also in human diseases. Recently, Vivo-Morpholinos, chemically modified morpholinos which penetrate the cells, have been used in adult experimental animal models to alter the splicing and thereby change the protein expression. Until now, there have been no such studies using Vivo-Morpholinos to evaluate hemostatic function in adult animals. We injected alphaIIb Vivo-Morpholinos intravenously into adult zebrafish. Thrombocyte function was assayed by time to aggregation assay of the citrated blood, annexin V binding to thrombocytes, and gill bleeding. The thrombocyte functional inhibition occurred in 24 h after alphaIIb Vivo-Morpholinos injection and reached a maximum in 48 h. However, in 72 h, the inhibition was no longer observed. Reduction of annexin V binding to thrombocytes and increased gill bleeding were observed 48 h after alphaIIb Vivo-Morpholino injections. The action of the alphaIIb Vivo-Morpholino was demonstrated by the presence of an alternatively spliced alphaIIb mRNA and the reduction of alphaIIb in thrombocytes of fish treated with alphaIIb Vivo-Morpholino. These results provide the first proof of principle that thrombocyte function can be inhibited by thrombocyte-specific Vivo-Morpholinos in adult zebrafish and presents an approach to knockdown thrombocyte-specific genes to conduct biochemical studies in thrombocytes. This study also provides the first antisense antithrombotic approach to inhibit thrombocyte function in adult zebrafish. PMID:20045356

Kim, Seongcheol; Radhakrishnan, Uvaraj P; Rajpurohit, Surendra Kumar; Kulkarni, Vrinda; Jagadeeswaran, Pudur

2010-03-15

164

Characterization of the RND family of multidrug efflux pumps: in silico to in vivo confirmation of four functionally distinct subgroups  

PubMed Central

Summary We have developed a generalized profile that identifies members of the root?nodulation?cell?division (RND) family of efflux pumps and classifies them into four functional subfamilies. According to Z?score values, efflux pumps can be grouped by their metabolic function, thus making it possible to distinguish pumps involved in antibiotic resistance (group 1) from those involved in metal resistance (group 3). In silico data regarding efflux pumps in group 1 were validated after identification of RND efflux pumps in a number of environmental microbes that were isolated as resistant to ethidium bromide. Analysis of the Pseudomonas putida KT2440 genome identified efflux pumps in all groups. A collection of mutants in efflux pumps and a screening platform consisting of 50 drugs were created to assign a function to the efflux pumps. We validated in silico data regarding efflux pumps in groups 1 and 3 using 9 different mutants. Four mutants belonging to group 2 were found to be more sensitive than the wild?type to oxidative stress?inducing agents such as bipyridyl and methyl viologen. The two remaining mutants belonging to group 4 were found to be more sensitive than the parental to tetracycline and one of them was particularly sensitive to rubidium and chromate. By effectively combining in vivo data with generalized profiles and gene annotation data, this approach allowed the assignment, according to metabolic function, of both known and uncharacterized RND efflux pumps into subgroups, thereby providing important new insight into the functions of proteins within this family.

Godoy, Patricia; Molina-Henares, Antonio J.; De La Torre, Jesus; Duque, Estrella; Ramos, Juan L.

2010-01-01

165

Analysis of superoscillatory wave functions  

Microsoft Academic Search

Surprisingly, differentiable functions are able to oscillate arbitrarily faster than their highest Fourier component would suggest. The phenomenon is called superoscillation. Recently, a practical method for calculating superoscillatory functions was presented and it was shown that superoscillatory quantum mechanical wave functions should exhibit a number of counter-intuitive physical effects. Following up on this work, we here present more general methods

Matt S. Calder; Achim Kempf

2005-01-01

166

Genome-Wide Screens for In Vivo Tinman Binding Sites Identify Cardiac Enhancers with Diverse Functional Architectures  

PubMed Central

The NK homeodomain factor Tinman is a crucial regulator of early mesoderm patterning and, together with the GATA factor Pannier and the Dorsocross T-box factors, serves as one of the key cardiogenic factors during specification and differentiation of heart cells. Although the basic framework of regulatory interactions driving heart development has been worked out, only about a dozen genes involved in heart development have been designated as direct Tinman target genes to date, and detailed information about the functional architectures of their cardiac enhancers is lacking. We have used immunoprecipitation of chromatin (ChIP) from embryos at two different stages of early cardiogenesis to obtain a global overview of the sequences bound by Tinman in vivo and their linked genes. Our data from the analysis of ?50 sequences with high Tinman occupancy show that the majority of such sequences act as enhancers in various mesodermal tissues in which Tinman is active. All of the dorsal mesodermal and cardiac enhancers, but not some of the others, require tinman function. The cardiac enhancers feature diverse arrangements of binding motifs for Tinman, Pannier, and Dorsocross. By employing these cardiac and non-cardiac enhancers in machine learning approaches, we identify a novel motif, termed CEE, as a classifier for cardiac enhancers. In vivo assays for the requirement of the binding motifs of Tinman, Pannier, and Dorsocross, as well as the CEE motifs in a set of cardiac enhancers, show that the Tinman sites are essential in all but one of the tested enhancers; although on occasion they can be functionally redundant with Dorsocross sites. The enhancers differ widely with respect to their requirement for Pannier, Dorsocross, and CEE sites, which we ascribe to their different position in the regulatory circuitry, their distinct temporal and spatial activities during cardiogenesis, and functional redundancies among different factor binding sites.

Jin, Hong; Stojnic, Robert; Adryan, Boris; Ozdemir, Anil; Stathopoulos, Angelike; Frasch, Manfred

2013-01-01

167

Non invasive in vivo investigation of hepatobiliary structure and function in STII medaka (Oryzias latipes): methodology and applications  

PubMed Central

Background A novel transparent stock of medaka (Oryzias latipes; STII), recessive for all pigments found in chromatophores, permits transcutaneous imaging of internal organs and tissues in living individuals. Findings presented describe the development of methodologies for non invasive in vivo investigation in STII medaka, and the successful application of these methodologies to in vivo study of hepatobiliary structure, function, and xenobiotic response, in both 2 and 3 dimensions. Results Using brightfield, and widefield and confocal fluorescence microscopy, coupled with the in vivo application of fluorescent probes, structural and functional features of the hepatobiliary system, and xenobiotic induced toxicity, were imaged at the cellular level, with high resolution (< 1 ?m), in living individuals. The findings presented demonstrate; (1) phenotypic response to xenobiotic exposure can be investigated/imaged in vivo with high resolution (< 1 ?m), (2) hepatobiliary transport of solutes from blood to bile can be qualitatively and quantitatively studied/imaged in vivo, (3) hepatobiliary architecture in this lower vertebrate liver can be studied in 3 dimensions, and (4) non invasive in vivo imaging/description of hepatobiliary development in this model can be investigated. Conclusion The non-invasive in vivo methodologies described are a unique means by which to investigate biological structure, function and xenobiotic response with high resolution in STII medaka. In vivo methodologies also provide the future opportunity to integrate molecular mechanisms (e.g., genomic, proteomic) of disease and toxicity with phenotypic changes at the cellular and system levels of biological organization. While our focus has been the hepatobiliary system, other organ systems are equally amenable to in vivo study, and we consider the potential for discovery, within the context of in vivo investigation in STII medaka, as significant.

Hardman, Ron C; Kullman, Seth W; Hinton, David E

2008-01-01

168

Translation initiation factors are not required for Dicistroviridae IRES function in vivo.  

PubMed

The cricket paralysis virus (CrPV) intergenic region (IGR) internal ribosome entry site (IRES) uses an unusual mechanism of initiating translation, whereby the IRES occupies the P-site of the ribosome and the initiating tRNA enters the A-site. In vitro experiments have demonstrated that the CrPV IGR IRES is able to bind purified ribosomes and form 80S complexes capable of synthesizing small peptides in the absence of any translation initiation factors. These results suggest that initiation by this IRES is factor-independent. To determine whether the IGR IRES functions in the absence of initiation factors in vivo, we assayed IGR IRES activity in various yeast strains harboring mutations in canonical translation initiation factors. We used a dicistronic reporter assay in yeast to determine whether the CrPV IGR IRES is able to promote translation sufficient to support growth in the presence of various deletions or mutations in translation initiation factors. Using this assay, we have previously shown that the CrPV IGR IRES functions efficiently in yeast when ternary complexes (eIF2*GTP*initiator tRNA(met)) are reduced. Here, we demonstrate that the CrPV IGR IRES activity does not require the eukaryotic initiation factors eIF4G1 or eIF5B, and it is enhanced when eIF2B, the eIF3b subunit of eIF3, or eIF4E are impaired. Taken together, these data support a model in which the CrPV IGR IRES is capable of initiating protein synthesis in the absence of any initiation factors in vivo, and suggests that the CrPV IGR IRES initiates translation by directly recruiting the ribosomal subunits in vivo. PMID:19299549

Deniz, Nilsa; Lenarcic, Erik M; Landry, Dori M; Thompson, Sunnie R

2009-05-01

169

Translation initiation factors are not required for Dicistroviridae IRES function in vivo  

PubMed Central

The cricket paralysis virus (CrPV) intergenic region (IGR) internal ribosome entry site (IRES) uses an unusual mechanism of initiating translation, whereby the IRES occupies the P-site of the ribosome and the initiating tRNA enters the A-site. In vitro experiments have demonstrated that the CrPV IGR IRES is able to bind purified ribosomes and form 80S complexes capable of synthesizing small peptides in the absence of any translation initiation factors. These results suggest that initiation by this IRES is factor-independent. To determine whether the IGR IRES functions in the absence of initiation factors in vivo, we assayed IGR IRES activity in various yeast strains harboring mutations in canonical translation initiation factors. We used a dicistronic reporter assay in yeast to determine whether the CrPV IGR IRES is able to promote translation sufficient to support growth in the presence of various deletions or mutations in translation initiation factors. Using this assay, we have previously shown that the CrPV IGR IRES functions efficiently in yeast when ternary complexes (eIF2•GTP•initiator tRNAmet) are reduced. Here, we demonstrate that the CrPV IGR IRES activity does not require the eukaryotic initiation factors eIF4G1 or eIF5B, and it is enhanced when eIF2B, the eIF3b subunit of eIF3, or eIF4E are impaired. Taken together, these data support a model in which the CrPV IGR IRES is capable of initiating protein synthesis in the absence of any initiation factors in vivo, and suggests that the CrPV IGR IRES initiates translation by directly recruiting the ribosomal subunits in vivo.

Deniz, Nilsa; Lenarcic, Erik M.; Landry, Dori M.; Thompson, Sunnie R.

2009-01-01

170

Allele Compensation in Tip60+/? Mice Rescues White Adipose Tissue Function In Vivo  

PubMed Central

Adipose tissue is a key regulator of energy homestasis. The amount of adipose tissue is largely determined by adipocyte differentiation (adipogenesis), a process that is regulated by the concerted actions of multiple transcription factors and cofactors. Based on in vitro studies in murine 3T3-L1 preadipocytes and human primary preadipocytes, the transcriptional cofactor and acetyltransferase Tip60 was recently identified as an essential adipogenic factor. We therefore investigated the role of Tip60 on adipocyte differentiation and function, and possible consequences on energy homeostasis, in vivo. Because homozygous inactivation results in early embryonic lethality, Tip60+/? mice were used. Heterozygous inactivation of Tip60 had no effect on body weight, despite slightly higher food intake by Tip60+/? mice. No major effects of heterozygous inactivation of Tip60 were observed on adipose tissue and liver, and Tip60+/? displayed normal glucose tolerance, both on a low fat and a high fat diet. While Tip60 mRNA was reduced to 50% in adipose tissue, the protein levels were unaltered, suggesting compensation by the intact allele. These findings indicate that the in vivo role of Tip60 in adipocyte differentiation and function cannot be properly addressed in Tip60+/? mice, but requires the generation of adipose tissue-specific knock out animals or specific knock-in mice.

Gao, Yuan; Hamers, Nicole; Rakhshandehroo, Maryam; Berger, Ruud; Lough, John; Kalkhoven, Eric

2014-01-01

171

E-cadherin is essential for in vivo epidermal barrier function by regulating tight junctions  

PubMed Central

Cadherin adhesion molecules are key determinants of morphogenesis and tissue architecture. Nevertheless, the molecular mechanisms responsible for the morphogenetic contributions of cadherins remain poorly understood in vivo. Besides supporting cell–cell adhesion, cadherins can affect a wide range of cellular functions that include activation of cell signalling pathways, regulation of the cytoskeleton and control of cell polarity. To determine the role of E-cadherin in stratified epithelium of the epidermis, we have conditionally inactivated its gene in mice. Here we show that loss of E-cadherin in the epidermis in vivo results in perinatal death of mice due to the inability to retain a functional epidermal water barrier. Absence of E-cadherin leads to improper localization of key tight junctional proteins, resulting in permeable tight junctions and thus altered epidermal resistance. In addition, both Rac and activated atypical PKC, crucial for tight junction formation, are mislocalized. Surprisingly, our results indicate that E-cadherin is specifically required for tight junction, but not desmosome, formation and this appears to involve signalling rather than cell contact formation.

Tunggal, Judith A; Helfrich, Iris; Schmitz, Annika; Schwarz, Heinz; Gunzel, Dorothee; Fromm, Michael; Kemler, Rolf; Krieg, Thomas; Niessen, Carien M

2005-01-01

172

Functional antagonism between histone H3K4 demethylases in vivo  

PubMed Central

Dynamic regulation of histone modifications is critical during development, and aberrant activity of chromatin-modifying enzymes has been associated with diseases such as cancer. Histone demethylases have been shown to play a key role in eukaryotic gene transcription; however, little is known about how their activities are coordinated in vivo to regulate specific biological processes. In Drosophila, two enzymes, dLsd1 (Drosophila ortholog of lysine-specific demethylase 1) and Lid (little imaginal discs), demethylate histone H3 at Lys 4 (H3K4), a residue whose methylation is associated with actively transcribed genes. Our studies show that compound mutation of Lid and dLsd1 results in increased H3K4 methylation levels. However, unexpectedly, Lid mutations strongly suppress dLsd1 mutant phenotypes. Investigation of the basis for this antagonism revealed that Lid opposes the functions of dLsd1 and the histone methyltransferase Su(var)3–9 in promoting heterochromatin spreading at heterochromatin–euchromatin boundaries. Moreover, our data reveal a novel role for dLsd1 in Notch signaling in Drosophila, and a complex network of interactions between dLsd1, Lid, and Notch signaling at euchromatic genes. These findings illustrate the complexity of functional interplay between histone demethylases in vivo, providing insights into the epigenetic regulation of heterochromatin/euchromatin boundaries by Lid and dLsd1 and showing their involvement in Notch pathway-specific control of gene expression in euchromatin.

Di Stefano, Luisa; Walker, James A.; Burgio, Giosalba; Corona, Davide F.V.; Mulligan, Peter; Naar, Anders M.; Dyson, Nicholas J.

2011-01-01

173

Tyrosine Phosphatase Epsilon Is a Positive Regulator of Osteoclast Function in Vitro and In Vivo  

PubMed Central

Protein tyrosine phosphorylation is a major regulator of bone metabolism. Tyrosine phosphatases participate in regulating phosphorylation, but roles of specific phosphatases in bone metabolism are largely unknown. We demonstrate that young (<12 weeks) female mice lacking tyrosine phosphatase epsilon (PTP?) exhibit increased trabecular bone mass due to cell-specific defects in osteoclast function. These defects are manifested in vivo as reduced association of osteoclasts with bone and as reduced serum concentration of C-terminal collagen telopeptides, specific products of osteoclast-mediated bone degradation. Osteoclast-like cells are generated readily from PTP?-deficient bone-marrow precursors. However, cultures of these cells contain few mature, polarized cells and perform poorly in bone resorption assays in vitro. Podosomes, structures by which osteoclasts adhere to matrix, are disorganized and tend to form large clusters in these cells, suggesting that lack of PTP? adversely affects podosomal arrangement in the final stages of osteoclast polarization. The gender and age specificities of the bone phenotype suggest that it is modulated by hormonal status, despite normal serum levels of estrogen and progesterone in affected mice. Stimulation of bone resorption by RANKL and, surprisingly, Src activity and Pyk2 phosphorylation are normal in PTP?-deficient osteoclasts, indicating that loss of PTP? does not cause widespread disruption of these signaling pathways. These results establish PTP? as a phosphatase required for optimal structure, subcellular organization, and function of osteoclasts in vivo and in vitro.

Chiusaroli, Riccardo; Knobler, Hilla; Luxenburg, Chen; Sanjay, Archana; Granot-Attas, Shira; Tiran, Zohar; Miyazaki, Tsuyoshi; Harmelin, Alon; Baron, Roland; Elson, Ari

2004-01-01

174

Numerical and In Vivo Validation of Fast Cine DENSE MRI for Quantification of Regional Cardiac Function  

PubMed Central

Quantitative assessment of regional cardiac function can improve the accuracy of detecting wall motion abnormalities due to heart disease. While recently developed fast cine displacement-encoded with stimulated echoes (DENSE) MRI is a promising modality for the quantification of regional myocardial function, it has not been validated for clinical applications. The purpose of this study, therefore, was to validate the accuracy of fast cine DENSE MRI with numerical simulation and in vivo experiments. A numerical phantom was generated to model physiologically relevant deformation of the heart, and the accuracy of fast cine DENSE was evaluated against the numerical reference. For in vivo validation, 12 controls and 13 heart disease patients were imaged using both fast cine DENSE and myocardial tagged MRI. Numerical simulation demonstrated that the echo-combination DENSE reconstruction method is relatively insensitive to clinically relevant resonance frequency offsets. The strain measurements by fast cine DENSE and the numerical reference were strongly correlated and in excellent agreement (mean difference=0.00; 95% limits of agreement were 0.01 and ?0.02). The strain measurements by fast cine DENSE and myocardial tagged MRI were strongly correlated (correlation coefficient = 0.92) and in good agreement (mean difference=0.01; 95% limits of agreement were 0.07 and ?0.04).

Feng, Li; Donnino, Robert; Babb, James; Axel, Leon; Kim, Daniel

2009-01-01

175

Tartary buckwheat improves cognition and memory function in an in vivo amyloid-?-induced Alzheimer model.  

PubMed

Protective effects of Tartary buckwheat (TB) and common buckwheat (CB) on amyloid beta (A?)-induced impairment of cognition and memory function were investigated in vivo in order to identify potential therapeutic agents against Alzheimer's disease (AD) and its associated progressive memory deficits, cognitive impairment, and personality changes. An in vivo mouse model of AD was created by injecting the brains of ICR mice with A?(25-35), a fragment of the full-length A? protein. Damage of mice recognition ability through following A?(25-35) brain injections was confirmed using the T-maze test, the object recognition test, and the Morris water maze test. Results of behavior tests in AD model showed that oral administration of the methanol (MeOH) extracts of TB and CB improved cognition and memory function following A?(25-35) injections. Furthermore, in groups receiving the MeOH extracts of TB and CB, lipid peroxidation was significantly inhibited, and nitric oxide levels in tissue, which are elevated by injection of A?(25-35), were also decrease. In particular, the MeOH extract of TB exerted a stronger protective activity than CB against A?(25-35)-induced memory and cognition impairment. The results indicate that TB may play a promising role in preventing or reversing memory and cognition loss associated with A?(25-35)-induced AD. PMID:23219778

Choi, Ji Yeon; Cho, Eun Ju; Lee, Hae Song; Lee, Jeong Min; Yoon, Young-Ho; Lee, Sanghyun

2013-03-01

176

An In Vivo Functional Screen Uncovers miR-150-Mediated Regulation of Hematopoietic Injury Response  

PubMed Central

Summary Hematopoietic stem and progenitor cells are often undesired targets of chemotherapies, leading to hematopoietic suppression requiring careful clinical management. Whether microRNAs control hematopoietic-injury response is largely unknown. We report a novel in vivo gain-of-function screen and identification of miR-150 as an inhibitor of hematopoietic recovery upon 5-fluorouracil-induced injury. Utilizing a bone marrow transplant model with a barcoded microRNA-library, we screened for barcode abundance in peripheral blood of recipient mice before and after 5-fluorouracil treatment. Overexpression of screen-candidate miR-150 resulted in significantly slowed recovery rates across major blood lineages, with associated impairment of bone marrow clonogenic potential. Conversely, platelets and myeloid cells from miR-150-null marrow recovered faster after 5-fluorouracil treatment. Heterozygous knockout of c-myb, a conserved target of miR-150, partially phenocopied miR-150 forced expression. Our data highlight the role of microRNAs in controlling hematopoietic-injury response, and demonstrate the power of in vivo functional screens for studying microRNAs in normal tissue physiology.

Adams, Brian D.; Guo, Shangqin; Bai, Haitao; Guo, Yanwen; Megyola, Cynthia; Cheng, Jijun; Heydari, Kartoosh; Xiao, Changchun; Reddy, E. Premkumar; Lu, Jun

2012-01-01

177

Predicting In Vivo Anti-Hepatofibrotic Drug Efficacy Based on In Vitro High-Content Analysis  

PubMed Central

Background/Aims Many anti-fibrotic drugs with high in vitro efficacies fail to produce significant effects in vivo. The aim of this work is to use a statistical approach to design a numerical predictor that correlates better with in vivo outcomes. Methods High-content analysis (HCA) was performed with 49 drugs on hepatic stellate cells (HSCs) LX-2 stained with 10 fibrotic markers. ?0.3 billion feature values from all cells in >150,000 images were quantified to reflect the drug effects. A systematic literature search on the in vivo effects of all 49 drugs on hepatofibrotic rats yields 28 papers with histological scores. The in vivo and in vitro datasets were used to compute a single efficacy predictor (Epredict). Results We used in vivo data from one context (CCl4 rats with drug treatments) to optimize the computation of Epredict. This optimized relationship was independently validated using in vivo data from two different contexts (treatment of DMN rats and prevention of CCl4 induction). A linear in vitro-in vivo correlation was consistently observed in all the three contexts. We used Epredict values to cluster drugs according to efficacy; and found that high-efficacy drugs tended to target proliferation, apoptosis and contractility of HSCs. Conclusions The Epredict statistic, based on a prioritized combination of in vitro features, provides a better correlation between in vitro and in vivo drug response than any of the traditional in vitro markers considered.

Zheng, Baixue; Tan, Looling; Mo, Xuejun; Yu, Weimiao; Wang, Yan; Tucker-Kellogg, Lisa; Welsch, Roy E.; So, Peter T. C.; Yu, Hanry

2011-01-01

178

Optimized ratiometric calcium sensors for functional in vivo imaging of neurons and T lymphocytes.  

PubMed

The quality of genetically encoded calcium indicators (GECIs) has improved dramatically in recent years, but high-performing ratiometric indicators are still rare. Here we describe a series of fluorescence resonance energy transfer (FRET)-based calcium biosensors with a reduced number of calcium binding sites per sensor. These 'Twitch' sensors are based on the C-terminal domain of Opsanus troponin C. Their FRET responses were optimized by a large-scale functional screen in bacterial colonies, refined by a secondary screen in rat hippocampal neuron cultures. We tested the in vivo performance of the most sensitive variants in the brain and lymph nodes of mice. The sensitivity of the Twitch sensors matched that of synthetic calcium dyes and allowed visualization of tonic action potential firing in neurons and high resolution functional tracking of T lymphocytes. Given their ratiometric readout, their brightness, large dynamic range and linear response properties, Twitch sensors represent versatile tools for neuroscience and immunology. PMID:24390440

Thestrup, Thomas; Litzlbauer, Julia; Bartholomäus, Ingo; Mues, Marsilius; Russo, Luigi; Dana, Hod; Kovalchuk, Yuri; Liang, Yajie; Kalamakis, Georgios; Laukat, Yvonne; Becker, Stefan; Witte, Gregor; Geiger, Anselm; Allen, Taylor; Rome, Lawrence C; Chen, Tsai-Wen; Kim, Douglas S; Garaschuk, Olga; Griesinger, Christian; Griesbeck, Oliver

2014-02-01

179

Selective Small Molecule Targeting ?-Catenin Function Discovered by In Vivo Chemical Genetic Screen  

PubMed Central

SUMMARY Canonical Wnt signaling pathway, mediated by the transcription factor ?-catenin, plays critical roles in embryonic development, and represents an important therapeutic target. In a zebrafish-based in vivo screen for small molecules that specifically perturb embryonic dorsoventral patterning, we discovered a novel compound, named windorphen, which selectively blocks the Wnt signal required for ventral development. Windorphen exhibits remarkable specificity toward ?-catenin-1 function, indicating that the two ?-catenin isoforms found in zebrafish are not functionally redundant. We show that windorphen is a selective inhibitor of p300 histone acetyl transferase, a co-activator that associates with ?-catenin. Lastly, windorphen robustly and selectively kills cancer cells that harbor Wnt-activating mutations, supporting the therapeutic potential of this novel Wnt inhibitor class.

Hao, Jijun; Ao, Ada; Zhou, Li; Murphy, Clare K.; Frist, Audrey Y.; Keel, Jessica J.; Thorne, Curtis A.; Kim, Kwangho; Lee, Ethan; Hong, Charles C.

2013-01-01

180

Functional Brain Image Analysis Using Joint Function-Structure Priors  

PubMed Central

We propose a new method for context-driven analysis of functional magnetic resonance images (fMRI) that incorporates spatial relationships between functional parameter clusters and anatomical structure directly for the first time. We design a parametric scheme that relates functional and structural spatially-compact regions in a single unified manner. Our method is motivated by the fact that the fMRI and anatomical MRI (aMRI) have consistent relations that provide configurations and context that aid in fMRI analysis. We develop a statistical decision-making strategy to estimate new fMRI parameter images (based on a General Linear Model-GLM) and spatially-clustered zones within these images. The analysis is based on the time-series data and contextual information related to appropriate spatial grouping of parameters in the functional data and the relationship of this grouping to relevant gray matter structure from the anatomical data. We introduce a representation for the joint prior of the functional and structural information, and define a joint probability distribution over the variations of functional clusters and the related structure contained in a set of training images. We estimate the Maximum A Posteriori (MAP) functional parameters, formulating the function-structure model in terms of level set functions. Results from 3D fMRI and aMRI show that this context-driven analysis potentially extracts more meaningful information than the standard GLM approach.

Yang, Jing; Papademetris, Xenophon; Staib, Lawrence H.; Schultz, Robert T.; Duncan, James S.

2010-01-01

181

Antitumor effector functions of T cells are dependent on in vivo priming and restricted T-cell receptor expression.  

PubMed

Tumor-specific T cells are crucial for immunologic control of malignant disease. T cells can be induced in vivo by vaccination or adoptively transferred after activation ex vivo. We investigated the requirements for generating T cells with optimal antitumor effector functions in a murine lymphoma model. Using adoptive transfer, we show that in vivo efficacy of T cells cannot be predicted by tumor reactivity in vitro. A restricted T-cell receptor beta chain repertoire of T-cell populations stimulated ex vivo against tumor cells was necessary but not sufficient for tumor protectivity. Tumor elimination furthermore required vaccination of donor mice, hence in vivo priming. The in vivo priming step may allow tumor-specific T cells to accumulate in vitro more rapidly and to survive for longer periods after withdrawal of the antigenic stimulus and adoptive transfer. A possible survival benefit of in vivo induced T cells may be ascribed to the responsiveness to homeostatic cytokines and to unique cytokine milieus encountered in vivo. Most importantly, monoclonal T cells cannot inhibit tumor growth. A prerequisite of tumor rejection was the expression of at least 2 T-cell receptor beta chains by transferred T-cell populations. This finding has implications for designing adoptive transfer strategies for the clinic. PMID:18224683

Lüking, Carolin; Kronenberger, Konrad; Frankenberger, Bernhard; Nössner, Elfriede; Röcken, Martin; Mocikat, Ralph

2008-05-15

182

Teacher Praise: A Functional Analysis.  

ERIC Educational Resources Information Center

Teacher praise typically does not function as a reinforcer. Rather, it is reactive to and under the control of student behavior. Its effects must be understood using concepts from attribution and social learning/reinforcement theories. (Author/GK)

Brophy, Jere

1981-01-01

183

Singularity Analysis of Generating Functions  

Microsoft Academic Search

This work presents a class of methods by which one can translate, on a term-by-term basis, an asymptotic expansion ofa function around a dominant singularity into a corresponding asymptotic expansion for the Taylor coefficients ofthe function. This approach is based on contour integration using Cauchy's formula and Hankel-like contours. It constitutes an alternative to either Darboux's method or Tauberian theorems

Philippe Flajolet; Andrew M. Odlyzko

1990-01-01

184

Functional Techniques for Data Analysis  

NASA Technical Reports Server (NTRS)

This dissertation develops a new general method of solving Prony's problem. Two special cases of this new method have been developed previously. They are the Matrix Pencil and the Osculatory Interpolation. The dissertation shows that they are instances of a more general solution type which allows a wide ranging class of linear functional to be used in the solution of the problem. This class provides a continuum of functionals which provide new methods that can be used to solve Prony's problem.

Tomlinson, John R.

1997-01-01

185

Series analysis of multivalued functions  

SciTech Connect

A recurrent problem in mathematical physics, for example, in the theory of critical phenomena, is the need to study the structure of physically interesting functions at a branch point of a complex structure usually called a ''confluent singularity.'' In such a neighborhood the function is necessarily multivalued. In addition, the value of such a function is sometimes required on a branch cut or even off the first Riemann sheet. Our approach to this problem is inspired by the Riemann (global) monodromy theorem and consists of using series expansions to form integral approximants (special case of Hermite-Pade approximants) to represent multivalued functions on multiple Riemann sheets. We prove an analogous local-monodromy-theorem, functional-representation results. We further identify the important ''separation property'' and use it to prove a convergence theorem for horizontal sequences of integral approximants. We make an extensive numerical investigation, using horizontal, diagonal, and constrained diagonal sequences, and find that these methods give excellent results on a wide variety of test functions of rather complex structure.

Baker G.A. Jr.; Oitmaa, J.; Velgakis, M.J.

1988-11-15

186

Body adiposity dictates different mechanisms of increased coronary reactivity related to improved in vivo cardiac function  

PubMed Central

Background Saturated fatty acid-rich high fat (HF) diets trigger abdominal adiposity, insulin resistance, type 2 diabetes and cardiac dysfunction. This study was aimed at evaluating the effects of nascent obesity on the cardiac function of animals fed a high-fat diet and at analyzing the mechanisms by which these alterations occurred at the level of coronary reserve. Materials and methods Rats were fed a control (C) or a HF diet containing high proportions of saturated fatty acids for 3 months. Thereafter, their cardiac function was evaluated in vivo using a pressure probe inserted into the cavity of the left ventricle. Their heart was isolated, perfused iso-volumetrically according to the Langendorff mode and the coronary reserve was evaluated by determining the endothelial-dependent (EDV) and endothelial-independent (EIV) vasodilatations in the absence and presence of endothelial nitric oxide synthase and cyclooxygenase inhibitors (L-NAME and indomethacin). The fatty acid composition of cardiac phospholipids was then evaluated. Results Although all the HF-fed rats increased their abdominal adiposity, some of them did not gain body weight (HF- group) compared to the C group whereas other ones had a higher body weight (HF+). All HF rats displayed a higher in vivo cardiac activity associated with an increased EDV. In the HF- group, the improved EDV was due to an increase in the endothelial cell vasodilatation activity whereas in the HF+?group, the enhanced EDV resulted from an improved sensitivity of coronary smooth muscle cells to nitric oxide. Furthermore, in the HF- group the main pathway implicated in the EDV was the NOS pathway while in the HF+?group the COX pathway. Conclusions Nascent obesity-induced improvement of cardiac function may be supported by an enhanced coronary reserve occurring via different mechanisms. These mechanisms implicate either the endothelial cells activity or the smooth muscle cells sensitivity depending on the body adiposity of the animals.

2014-01-01

187

Characterization of the structural and functional determinants of MANF/CDNF in Drosophila in vivo model.  

PubMed

Mammalian MANF and CDNF proteins are evolutionarily conserved neurotrophic factors that can protect and repair mammalian dopaminergic neurons in vivo. In Drosophila, the sole MANF protein (DmManf) is needed for the maintenance of dopaminergic neurites and dopamine levels. Although both secreted and intracellular roles for MANF and CDNF have been demonstrated, very little is known about the molecular mechanism of their action. Here, by using a transgenic rescue approach in the DmManf mutant background we show that only full-length MANF containing both the amino-terminal saposin-like and carboxy-terminal SAP-domains can rescue the larval lethality of the DmManf mutant. Independent N- or C-terminal domains of MANF, even when co-expressed together, fail to rescue. Deleting the signal peptide or mutating the CXXC motif in the C-terminal domain destroys the activity of full-length DmManf. Positively charged surface amino acids and the C-terminal endoplasmic reticulum retention signal are necessary for rescue of DmManf mutant lethality when DmManf is expressed in a restricted pattern. Furthermore, rescue experiments with non-ubiquitous expression reveals functional differences between the C-terminal domain of human MANF and CDNF. Finally, DmManf and its C-terminal domain rescue mammalian sympathetic neurons from toxin-induced apoptosis in vitro demonstrating functional similarity of the mammalian and fly proteins. Our study offers further insights into the functional conservation between invertebrate and mammalian MANF/CDNF proteins and reveals the importance of the C-terminal domain for MANF activity in vivo. PMID:24019940

Lindström, Riitta; Lindholm, Päivi; Kallijärvi, Jukka; Yu, Li-Ying; Piepponen, T Petteri; Arumäe, Urmas; Saarma, Mart; Heino, Tapio I

2013-01-01

188

Characterization of the Structural and Functional Determinants of MANF/CDNF in Drosophila In Vivo Model  

PubMed Central

Mammalian MANF and CDNF proteins are evolutionarily conserved neurotrophic factors that can protect and repair mammalian dopaminergic neurons in vivo. In Drosophila, the sole MANF protein (DmManf) is needed for the maintenance of dopaminergic neurites and dopamine levels. Although both secreted and intracellular roles for MANF and CDNF have been demonstrated, very little is known about the molecular mechanism of their action. Here, by using a transgenic rescue approach in the DmManf mutant background we show that only full-length MANF containing both the amino-terminal saposin-like and carboxy-terminal SAP-domains can rescue the larval lethality of the DmManf mutant. Independent N- or C-terminal domains of MANF, even when co-expressed together, fail to rescue. Deleting the signal peptide or mutating the CXXC motif in the C-terminal domain destroys the activity of full-length DmManf. Positively charged surface amino acids and the C-terminal endoplasmic reticulum retention signal are necessary for rescue of DmManf mutant lethality when DmManf is expressed in a restricted pattern. Furthermore, rescue experiments with non-ubiquitous expression reveals functional differences between the C-terminal domain of human MANF and CDNF. Finally, DmManf and its C-terminal domain rescue mammalian sympathetic neurons from toxin-induced apoptosis in vitro demonstrating functional similarity of the mammalian and fly proteins. Our study offers further insights into the functional conservation between invertebrate and mammalian MANF/CDNF proteins and reveals the importance of the C-terminal domain for MANF activity in vivo.

Lindstrom, Riitta; Lindholm, Paivi; Kallijarvi, Jukka; Yu, Li-ying; Piepponen, T. Petteri; Arumae, Urmas; Saarma, Mart; Heino, Tapio I.

2013-01-01

189

Congenital Heart Disease-Causing Gata4 Mutation Displays Functional Deficits In Vivo  

PubMed Central

Defects of atrial and ventricular septation are the most frequent form of congenital heart disease, accounting for almost 50% of all cases. We previously reported that a heterozygous G296S missense mutation of GATA4 caused atrial and ventricular septal defects and pulmonary valve stenosis in humans. GATA4 encodes a cardiac transcription factor, and when deleted in mice it results in cardiac bifida and lethality by embryonic day (E)9.5. In vitro, the mutant GATA4 protein has a reduced DNA binding affinity and transcriptional activity and abolishes a physical interaction with TBX5, a transcription factor critical for normal heart formation. To characterize the mutation in vivo, we generated mice harboring the same mutation, Gata4 G295S. Mice homozygous for the Gata4 G295S mutant allele have normal ventral body patterning and heart looping, but have a thin ventricular myocardium, single ventricular chamber, and lethality by E11.5. While heterozygous Gata4 G295S mutant mice are viable, a subset of these mice have semilunar valve stenosis and small defects of the atrial septum. Gene expression studies of homozygous mutant mice suggest the G295S protein can sufficiently activate downstream targets of Gata4 in the endoderm but not in the developing heart. Cardiomyocyte proliferation deficits and decreased cardiac expression of CCND2, a member of the cyclin family and a direct target of Gata4, were found in embryos both homozygous and heterozygous for the Gata4 G295S allele. To further define functions of the Gata4 G295S mutation in vivo, compound mutant mice were generated in which specific cell lineages harbored both the Gata4 G295S mutant and Gata4 null alleles. Examination of these mice demonstrated that the Gata4 G295S protein has functional deficits in early myocardial development. In summary, the Gata4 G295S mutation functions as a hypomorph in vivo and leads to defects in cardiomyocyte proliferation during embryogenesis, which may contribute to the development of congenital heart defects in humans.

Misra, Chaitali; Sachan, Nita; McNally, Caryn Rothrock; Koenig, Sara N.; Nichols, Haley A.; Guggilam, Anuradha; Lucchesi, Pamela A.; Pu, William T.; Srivastava, Deepak; Garg, Vidu

2012-01-01

190

Imaging the Function of P-Glycoprotein With Radiotracers: Pharmacokinetics and In Vivo Applications  

PubMed Central

P-glycoprotein (P-gp), an efflux transporter, controls the pharmacokinetics of various compounds under physiological conditions. P-gp-mediated drug efflux has been suggested as playing a role in various disorders, including multidrug-resistant cancer and medication-refractory epilepsy. However, P-gp inhibition has had, to date, little or no clinically significant effect in multidrug-resistant cancer. To enhance our understanding of its in vivo function under pathophysiological conditions, substrates of P-gp have been radiolabeled and imaged using single-photon emission computed tomography (SPECT) and positron emission tomography (PET). To accurately quantify P-gp function, a radiolabeled P-gp substrate should be selective for P-gp, produce a large signal after P-gp blockade, and generate few radiometabolites that enter the target tissue. Furthermore, quantification of P-gp function via imaging requires pharmacological inhibition of P-gp, which requires knowledge of P-gp density at the target site. By meeting these criteria, imaging can elucidate the function of P-gp in various disorders and improve the efficacy of treatments.

Kannan, P; John, C; Zoghbi, SS; Halldin, C; Gottesman, MM; Innis, RB; Hall, MD

2009-01-01

191

Selective ex-vivo photothermal ablation of human pancreatic cancer with albumin functionalized multiwalled carbon nanotubes  

PubMed Central

The process of laser-mediated ablation of cancer cells marked with biofunctionalized carbon nanotubes is frequently called “nanophotothermolysis”. We herein present a method of selective nanophotothermolisys of pancreatic cancer (PC) using multiwalled carbon nanotubes (MWCNTs) functionalized with human serum albumin (HSA). With the purpose of testing the therapeutic value of these nanobioconjugates, we have developed an ex-vivo experimental platform. Surgically resected specimens from patients with PC were preserved in a cold medium and kept alive via intra-arterial perfusion. Additionally, the HSA-MWCNTs have been intra-arterially administered in the greater pancreatic artery under ultrasound guidance. Confocal and transmission electron microscopy combined with immunohistochemical staining have confirmed the selective accumulation of HSA-MWCNTs inside the human PC tissue. The external laser irradiation of the specimen has significantly produced extensive necrosis of the malign tissue after the intra-arterial administration of HSA-MWCNTs, without any harmful effects on the surrounding healthy parenchyma. We have obtained a selective photothermal ablation of the malign tissue based on the selective internalization of MWCNTs with HSA cargo inside the pancreatic adenocarcinoma after the ex-vivo intra-arterial perfusion.

Mocan, Lucian; Tabaran, Flaviu A; Mocan, Teodora; Bele, Constantin; Orza, Anamaria Ioana; Lucan, Ciprian; Stiufiuc, Rares; Manaila, Ioana; Iulia, Ferencz; Dana, Iancu; Zaharie, Florin; Osian, Gelu; Vlad, Liviu; Iancu, Cornel

2011-01-01

192

The JAK-inhibitor ruxolitinib impairs dendritic cell function in vitro and in vivo.  

PubMed

The Janus kinase (JAK)-inhibitor ruxolitinib decreases constitutional symptoms and spleen size of myelofibrosis (MF) patients by mechanisms distinct from its anticlonal activity. Here we investigated whether ruxolitinib affects dendritic cell (DC) biology. The in vitro development of monocyte-derived DCs was almost completely blocked when the compound was added throughout the differentiation period. Furthermore, when applied solely during the final lipopolysaccharide-induced maturation step, ruxolitinib reduced DC activation as demonstrated by decreased interleukin-12 production and attenuated expression of activation markers. Ruxolitinib also impaired both in vitro and in vivo DC migration. Dysfunction of ruxolitinib-exposed DCs was further underlined by their impaired induction of allogeneic and antigen-specific T-cell responses. Ruxolitinib-treated mice immunized with ovalbumin (OVA)/CpG induced markedly reduced in vivo activation and proliferation of OVA-specific CD8? T cells compared with vehicle-treated controls. Finally, using an adenoviral infection model, we show that ruxolitinib-exposed mice exhibit delayed adenoviral clearance. Our results demonstrate that ruxolitinib significantly affects DC differentiation and function leading to impaired T-cell activation. DC dysfunction may result in increased infection rates in ruxolitinib-treated patients. However, our findings may also explain the outstanding anti-inflammatory and immunomodulating activity of JAK inhibitors currently used in the treatment of MF and autoimmune diseases. PMID:23770777

Heine, Annkristin; Held, Stefanie Andrea Erika; Daecke, Solveig Nora; Wallner, Stephanie; Yajnanarayana, Sowmya Parampalli; Kurts, Christian; Wolf, Dominik; Brossart, Peter

2013-08-15

193

In Vitro Hematological and In Vivo Vasoactivity Assessment of Dextran Functionalized Graphene  

PubMed Central

The intravenous, intramuscular or intraperitoneal administration of water solubilized graphene nanoparticles for biomedical applications will result in their interaction with the hematological components and vasculature. Herein, we have investigated the effects of dextran functionalized graphene nanoplatelets (GNP-Dex) on histamine release, platelet activation, immune activation, blood cell hemolysis in vitro, and vasoactivity in vivo. The results indicate that GNP-Dex formulations prevented histamine release from activated RBL-2H3 rat mast cells, and at concentrations ? 7?mg/ml, showed a 12–20% increase in levels of complement proteins. Cytokine (TNF-Alpha and IL-10) levels remained within normal range. GNP-Dex formulations did not cause platelet activation or blood cell hemolysis. Using the hamster cheek pouch in vivo model, the initial vasoactivity of GNP-Dex at concentrations (1–50?mg/ml) equivalent to the first pass of a bolus injection was a brief concentration-dependent dilation in arcade and terminal arterioles. However, they did not induce a pro-inflammatory endothelial dysfunction effect.

Chowdhury, Sayan Mullick; Kanakia, Shruti; Toussaint, Jimmy D.; Frame, Mary D.; Dewar, Anthony M.; Shroyer, Kenneth R.; Moore, William; Sitharaman, Balaji

2013-01-01

194

Functional identification of Api5 as a suppressor of E2F-dependent apoptosis in vivo.  

PubMed

Retinoblastoma protein and E2-promoter binding factor (E2F) family members are important regulators of G1-S phase progression. Deregulated E2F also sensitizes cells to apoptosis, but this aspect of E2F function is poorly understood. Studies of E2F-induced apoptosis have mostly been carried out in tissue culture cells, and the analysis of the factors that are important for this process has been restricted to the testing of a few candidate genes. Using Drosophila as a model system, we have generated tools that allow genetic modifiers of E2F-dependent apoptosis to be identified in vivo and developed assays that allow effects on E2F-induced apoptosis to be studied in cultured cells. Genetic interactions show that dE2F1-dependent apoptosis in vivo involves dArk/Apaf1 apoptosome-dependent activation of both initiator and effector caspases and is sensitive to levels of Drosophila inhibitor of apoptosis-1 (dIAP1). Using these approaches, we report the surprising finding that apoptosis inhibitor-5/antiapoptosis clone-11 (Api5/Aac11) is a critical determinant of dE2F1-induced apoptosis in vivo and in vitro. This functional interaction occurs in multiple tissues, is specific to E2F-induced apoptosis, and is conserved from flies to humans. Interestingly, Api5/Aac11 acts downstream of E2F and suppresses E2F-dependent apoptosis without generally blocking E2F-dependent transcription. Api5/Aac11 expression is often upregulated in tumor cells, particularly in metastatic cells. We find that depletion of Api5 is tumor cell lethal. The strong genetic interaction between E2F and Api5/Aac11 suggests that elevated levels of Api5 may be selected during tumorigenesis to allow cells with deregulated E2F activity to survive under suboptimal conditions. Therefore, inhibition of Api5 function might offer a possible mechanism for antitumor exploitation. PMID:17112319

Morris, Erick J; Michaud, William A; Ji, Jun-Yuan; Moon, Nam-Sung; Rocco, James W; Dyson, Nicholas J

2006-11-17

195

In vivo and in vitro analysis of a bonding agent.  

PubMed

Recently many researchers have become interested in the adhesion of composite resin to the dentinal surface. Because it is easier to obtain good composite resin adhesion when a surface is free from smear plug, several chemical agents (acids or linking agents) have been suggested for surface preparation. Nevertheless, the pretreatment of dentin leads to an increase of pulpal outflow, which can interfere with the bonding agent's adhesion. Thus, new-generation dentinal bonding agents appeared on the market. They use a pool of highly absorbent primers to facilitate the scattering of the agent in the dentin substratum under humid conditions. The present study shows the results, obtained with the help of scanning electron microscopy, of resinous penetration into the tubular structures of dentin using a latest-generation bonding system. The in vivo and in vitro tests showed a deep scattering of intermediate fluid resin into tubules, even in the presence of physiologic outflow of dentinal fluids. PMID:7568716

Goracci, G; Bazzucchi, M; Mori, G; Casa dé Martinis, L

1994-09-01

196

Clinical applications of in vivo neutron-activation analysis  

SciTech Connect

In vivo neutron activation has opened a new era of both clinical diagnosis and therapy evaluation, and investigation into and modelling of body composition. The techniques are new, but it is already clear that considerable strides can be made in increasing accuracy and precision, increasing the number of elements susceptible to measurement, enhancing uniformity, and reducing the dose required for the measurement. The work presently underway will yield significant data on a variety of environmental contaminants such as Cd. Compositional studies are determining the level of vital constituents such as nitrogen and potassium in both normal subjects and in patients with a variety of metabolic disorders. Therapeutic programs can be assessed while in progress.

Cohn, S.H.

1982-01-01

197

Rapid Immunomagnetic Negative Enrichment of Neutrophil Granulocytes from Murine Bone Marrow for Functional Studies In Vitro and In Vivo  

PubMed Central

Polymorphonuclear neutrophils (PMN) mediate early immunity to infection but can also cause host damage if their effector functions are not controlled. Their lack or dysfunction is associated with severe health problems and thus the analysis of PMN physiology is a central issue. One prerequisite for PMN analysis is the availability of purified cells from primary organs. While human PMN are easily isolated from peripheral blood, this approach is less suitable for mice due to limited availability of blood. Instead, bone marrow (BM) is an easily available reservoir of murine PMN, but methods to obtain pure cells from BM are limited. We have developed a novel protocol allowing the isolation of highly pure untouched PMN from murine BM by negative immunomagnetic isolation using a complex antibody cocktail. The protocol is simple and fast (?1 h), has a high yield (5–10*106 PMN per animal) and provides a purity of cells equivalent to positive selection (>80%). Most importantly, cells obtained by this method are non-activated and remain fully functional in vitro or after adoptive transfer into recipient animals. This method should thus greatly facilitate the study of primary murine PMN in vitro and in vivo.

Hasenberg, Mike; Kohler, Anja; Bonifatius, Susanne; Borucki, Katrin; Riek-Burchardt, Monika; Achilles, Julia; Mann, Linda; Baumgart, Kathleen; Schraven, Burkhart; Gunzer, Matthias

2011-01-01

198

In vivo exposure to bicarbonate/lactate- and bicarbonate-buffered peritoneal dialysis fluids improves ex vivo peritoneal macrophage function.  

PubMed

The impact on peritoneal macrophage (PMO) function of acidic lactate-buffered (Lac-PDF [PD4]; 40 mmol/L of lactate; pH 5.2) and neutral-pH, bicarbonate-buffered (TB; 38 mmol/L of bicarbonate; pH 7. 3) and bicarbonate/lactate-buffered (TBL; 25 mmol/L of bicarbonate/15 mmol/L of lactate; pH 7.3) peritoneal dialysis fluids (PDFs) was compared during a study of continuous therapy with PD4, TB, or TBL. During a run-in phase of 6 weeks when all patients (n = 15) were treated with their regular dialysis regimen with Lac-PDF, median PMO tumor necrosis factor alpha (TNFalpha) release values were 203.6, 89.9, and 115.5 pg TNFalpha/10(6) PMO in the patients subsequently randomized to the PD4, TB, and TBL treatment groups, respectively. Median stimulated TNFalpha values (serum-treated zymosan [STZ], 10 microgram/mL) were 1,894.6, 567.3, and 554.5 pg TNFalpha/10(6) PMO in the same groups, respectively. During the trial phase of 12 weeks, when the three groups of patients (n = 5 per group) were randomized to continuous treatment with PD4, TB, or TBL, median constitutive TNFalpha release values were 204.7, 131.4, and 155.4 pg TNFalpha/10(6) PMO, respectively. Stimulated TNFalpha values (STZ, 10 microgram/mL) were 1,911, 1,832, and 1,378 pg TNFalpha/10(6) PMO in the same groups, respectively. Repeated-measures analysis of variance comparing the run-in phase with the trial phase showed that PMO TNFalpha release was significantly elevated in patients treated with both TB (P = 0.040) and TBL (P = 0.014) but not in patients treated with Lac-PDF (P = 0. 795). These data suggest that patients continuously exposed to bicarbonate- and bicarbonate/lactate-buffered PDFs might have better preserved PMO function and thus improved host defense status. PMID:10620552

Mackenzie, R K; Jones, S; Moseley, A; Holmes, C J; Argyle, R; Williams, J D; Coles, G A; Pu, K; Faict, D; Topley, N

2000-01-01

199

Functional Analysis and Reduction of Inappropriate Spitting  

ERIC Educational Resources Information Center

Functional analysis was used to determine the possible function of inappropriate spitting behavior of an adult woman who had been diagnosed with profound mental retardation. Results of an initial descriptive assessment indicated a possible attention function and led to an attention-based intervention, which was deemed ineffective at reducing the…

Carter, Stacy L.; Wheeler, John J.

2007-01-01

200

Ex vivo development, expansion and in vivo analysis of a novel lineage of dendritic cells from hematopoietic stem cells.  

PubMed

Dendritic cells (DCs) play a key role in innate and adaptive immunity but the access to sufficient amount of DCs for basic and translational research has been limited.We established a novel ex vivo system to develop and expand DCs from hematopoietic stem/progenitor cells (HPCs). Both human and mouse HPCs were expanded first in feeder culture supplemented with c-Kit ligand (KL, stem cell factor, steel factor or CD117 ligand), Flt3 ligand (fms-like tyrosine kinase 3, Flt3L, FL), thrombopoietin (TPO), IL-3, IL-6, and basic fibroblast growth factor (bFGF), and then in a second feeder culture ectopically expressing all above growth factors plus GM-CSF and IL-15.In the dual culture system, CD34+ HPCs differentiated toward DC progenitors (DCPs), which expanded more than five orders of magnitude. The DCPs showed myeloid DC surface phenotype with up-regulation of transcription factors PU.1 and Id2, and DC-related factors homeostatic chemokine ligand 17 (CCL17) and beta-chemokine receptor 6 (CCR6). Multiplex ELISA array and cDNA microarray analyses revealed that the DCPs shared some features of IL-4 and IL-15 DCs but displayed a pronounced proinflammatory phenotype. DCP-derived DCs showed antigen-uptake and immune activation functions analogous to that of the peripheral blood-derived DCs. Furthermore, bone marrow HPC-derived DCP vaccines of tumor-bearing mice suppressed tumor growth in vivo.This novel approach of generating DCP-DCs, which are different from known IL-4 and IL-15 DCs, overcomes both quantitative and qualitative limitations in obtaining functional autologous DCs from a small number of HPCs with great translational potential. PMID:21106069

Han, Shuhong; Wang, Yichen; Wang, Bei; Patel, Ekta; Okada, Starlyn; Yang, Li-Jun; Moreb, Jan S; Chang, Lung-Ji

2010-01-01

201

In vitro and in vivo evaluation of a novel ferrocyanide functionalized nanopourous silica decorporation agent for cesium in rats.  

PubMed

Novel decorporation agents are being developed to protect against radiological terrorist attacks. These sorbents, known as the self-assembled monolayer on mesoporous supports (SAMMS), are hybrid materials where differing organic moieties are grafted onto mesoporous silica (SiO(2)). In vitro experiments focused on the evaluation and optimization of SAMMS for capturing radiocesium ((137)Cs); therefore, based on these studies, a ferrocyanide copper (FC-Cu-EDA)-SAMMS was advanced for in vivo evaluation. In vivo experiments were conducted comparing the performance of the SAMMS vs. insoluble Prussian blue. Groups of jugular cannulated rats (4/treatment) were evaluated. Animals in Group I were administered (137)Cs chloride (approximately 40 microg kg(-1)) by intravenous (i.v.) injection or oral gavage; Group II animals were administered pre-bound (137)Cs-SAMMS or sequential Cs chloride + SAMMS (approximately 61 ng kg(-1)) by oral gavage; and Group III was orally administered (137)Cs chloride (approximately 61 ng kg(-1)) followed by either 0.1 g of SAMMS or Prussian blue. Following dosing, the rats were maintained in metabolism cages for 72 h and blood, urine, and fecal samples were collected for (137)Cs analysis (gamma counting). Rats were then humanely euthanized, and selected tissues analyzed. Orally administered (137)Cs chloride was rapidly and well absorbed (approximately 100% relative to i.v. dose), and the pharmacokinetics (blood, urine, feces, and tissues) were very comparable to the i.v. dose group. For both exposures the urine and feces accounted for 20 and 3% of the dose, respectively. The prebound (137)Cs-SAMMS was retained primarily within the feces (72% of the dose), with approximately 1.4% detected in the urine, suggesting that the (137)Cs remained tightly bound to SAMMS. SAMMS and Prussian blue both effectively captured available (137)Cs in the gut with feces accounting for 80-88% of the administered dose, while less than 2% was detected in the urine. This study suggests that the functionalized SAMMS outperforms Prussian blue in vitro at low pH, but demonstrates comparable in vivo sequestration efficacy at low exposure concentrations. The comparable response may be the result of the low (137)Cs chloride dose and high sorbent dosage that was utilized. Future studies are planned to optimize the performance of SAMMS in vivo over a broader range of doses and conditions. PMID:20699707

Timchalk, Charles; Creim, Jeffrey A; Sukwarotwat, Vichaya; Wiacek, Robert; Addleman, R Shane; Fryxell, Glen E; Yantasee, Wassana

2010-09-01

202

In Vitro and In Vivo Evaluation of a Novel Ferrocyanide Functionalized Nanopourous Silica Decorporation Agent for Cesium in Rats  

SciTech Connect

Novel decorporation agents are being developed to protect against radiological terrorist attacks. These sorbents, known as the self-assembled monolayer on mesoporous supports (SAMMS™), are hybrid materials where differing organic moieties are grafted onto mesoporous silica (SiO2). In vitro experiments focused on the evaluation, and optimization of SAMMS for capturing radiocesium (137Cs); based on these studies, a ferrocyanide copper (FC-Cu-EDA)-SAMMS was advanced for in vivo evaluation. In vivo experiments were conducted comparing the performance of the SAMMS vs. insoluble Prussian blue. Groups of jugular cannulated rats (4/treatment) were evaluated. Group I was administered 137Cs (~40 ?geq/kg) by intravenous (iv) injection and oral gavage; Group II was administered pre-bound 137Cs-SAMMS and sequential 137Cs + SAMMS (~61 ngeq/kg) by oral gavage; and Group III evaluated orally administered 137Cs (~0.06 ?geq/kg) followed by 0.1 g of either SAMMS or Prussian blue. Following dosing the rats were maintained in metabolism cages for 72 hour and blood, urine and fecal samples were collected for 137Cs analysis (gamma counting). Rats were then humanely euthanized, and selected tissues analyzed. Orally administered 137Cs was rapidly and well absorbed (~100% relative to iv dose), and the pharmacokinetics (blood, urine, feces & tissues) were very comparable to the iv dose group. For both exposures the urine and feces accounted for 20 and 3% of the dose, respectively. The prebound 137Cs-SAMMS was retained primarily within the feces (72% of the dose), with ~1.4% detected in the urine, suggesting that the 137Cs remained tightly bound to SAMMS. SAMMS & Prussian blue both effectively captured available 137Cs in the gut with feces accounting for 80-88% of the administered dose, while less than 2% was detected in the urine. This study suggests that the functionalized SAMMS out performs Prussian blue in vitro at low pH, but demonstrates comparable in vivo sequestration efficacy at low exposure concentrations. The comparable response may be the result of the low 137Cs dose and high sorbent dosage that was utilized. Future studies are planned to optimize SAMMS in vivo performance over a broader range of doses and conditions.

Timchalk, Charles; Creim, Jeffrey A.; Sukwarotwat, Vichaya; Wiacek, Robert J.; Addleman, Raymond S.; Fryxell, Glen E.; Yantasee, Wassana

2010-09-01

203

Biomimetic modification of metallic cardiovascular biomaterials: from function mimicking to endothelialization in vivo  

PubMed Central

Biosystem–surface interactions play an important role in various biological events and determine the ultimate functionality of implanted devices. Endothelialization or mimicking of endothelium on the surface of cardiovascular materials is a promising way to solve the problems of material-induced thrombosis and restenosis. Meanwhile, a multifunctional surface design is needed as antithrombotic properties should be considered in the period when the implants are not yet completely endothelialized. In this article, we summarize some successful approaches used in our laboratory for constructing multifunctional endothelium-like surfaces on metallic cardiovascular biomaterials through chemical modification of the surface or by the introduction of specific biological molecules to induce self-endothelialization in vivo. Some directions on future research in these areas are also presented.

Weng, Yajun; Chen, Junying; Tu, Qiufen; Li, Quanli; Maitz, Manfred F.; Huang, Nan

2012-01-01

204

In vivo functional properties of juxtaglomerular neurons in the mouse olfactory bulb  

PubMed Central

Juxtaglomerular neurons represent one of the largest cellular populations in the mammalian olfactory bulb yet their role for signal processing remains unclear. We used two-photon imaging and electrophysiological recordings to clarify the in vivo properties of these cells and their functional organization in the juxtaglomerular space. Juxtaglomerular neurons coded for many perceptual characteristics of the olfactory stimulus such as (1) identity of the odorant, (2) odorant concentration, (3) odorant onset, and (4) offset. The odor-responsive neurons clustered within a narrow area surrounding the glomerulus with the same odorant specificity, with ~80% of responding cells located ?20 ?m from the glomerular border. This stereotypic spatial pattern of activated cells persisted at different odorant concentrations and was found for neurons both activated and inhibited by the odorant. Our data identify a principal glomerulus with a narrow shell of juxtaglomerular neurons as a basic odor coding unit in the glomerular layer and underline the important role of intraglomerular circuitry.

Homma, R.; Kovalchuk, Y.; Konnerth, A.; Cohen, L. B.; Garaschuk, O.

2013-01-01

205

Formulation/Preparation of Functionalized Nanoparticles for In Vivo Targeted Drug Delivery  

NASA Astrophysics Data System (ADS)

Targeted cancer therapy allows the delivery of therapeutic agents to cancer cells without incurring undesirable side effects on the neighboring healthy tissues. Over the past decade, there has been an increasing interest in the development of advanced cancer therapeutics using targeted nanoparticles. Here we describe the preparation of drug-encapsulated nanoparticles formulated with biocompatible and biodegradable poly( d, l-lactic-co-glycolic acid)-block-poly(ethylene glycol) (PLGA-b-PEG) copolymer and surface functionalized with the A10 2-fluoropyrimidine ribonucleic acid aptamers that recognize the extracellular domain of prostate-specific membrane antigen (PSMA), a well-characterized antigen expressed on the surface of prostate cancer cells. We show that the self-assembled nanoparticles can selectively bind to PSMA-targeted prostate cancer cells in vitro and in vivo. This formulation method may contribute to the development of highly selective and effective cancer therapeutic and diagnostic devices.

Gu, Frank; Langer, Robert; Farokhzad, Omid C.

206

Formulation/Preparation of Functionalized Nanoparticles for In Vivo Targeted Drug Delivery  

PubMed Central

Summary Targeted cancer therapy allows the delivery of therapeutic agents to cancer cells without incurring undesirable side effects on the neighboring healthy tissues. Over the past decade, there has been an increasing interest in the development of advanced cancer therapeutics using targeted nanoparticles. Here we describe the preparation of drug-encapsulated nanoparticles formulated with biocompatible and biodegradable poly(D,L-lactic-co-glycolic acid)-block-poly(ethylene glycol) (PLGA-b-PEG) copolymer and surface functionalized with the A10 2-fluoropyrimidine ribonucleic acid aptamers that recognize the extracellular domain of prostate-specific membrane antigen (PSMA), a well-characterized antigen expressed on the surface of prostate cancer cells. We show that the self-assembled nanoparticles can selectively bind to PSMA-targeted prostate cancer cells in vitro and in vivo. This formulation method may contribute to the development of highly selective and effective cancer therapeutic and diagnostic devices.

Gu, Frank; Langer, Robert; Farokhzad, Omid C.

2014-01-01

207

In vivo effects of monoclonal antibodies that functionally inhibit complement regulatory proteins in rats  

PubMed Central

The present work was designed to evaluate the effects of functional suppression of complement regulatory proteins in vivo. Male Wistar rats were anesthetized with Nembutal and were intravenously injected with 1 mg/kg of F(ab')2 or Fab fraction of either monoclonal antibody 5I2, which inhibits the function of rat counterpart of mouse Crry/p65, or monoclonal antibody 6D1, which inhibits the rat counterpart of CD59. Mean arterial pressure was continuously measured for 30 min. When 5I2 was injected, there was a biphasic change of mean arterial pressure, namely, the rapid increase immediately after the injection (approximately 2 min, phase 1) and the subsequent fall and slow recovery (approximately 4-30 min, phase 2). These effects were completely abrogated by pretreatment of rats with cobra venom factor. Pretreatment with carboxypeptidase inhibitor, which inhibits inactivation of anaphylatoxins C3a and C5a, induced enhanced reduction of blood pressure. Circulating leukocytes and platelets were rapidly decreased 5 min after antibody injection and became normal by 2 h. Hematocrit and erythrocyte count were continuously increased up to 2 h after injection, suggesting that there was hemoconcentration due to increased vascular permeability. Immunofluorescence study revealed binding of antibody fragments and rat C3 along the capillaries of lung, heart, and liver 5 min after injection. In contrast to 5I2, F(ab')2 fraction of 6D1, though localized to the same areas and in similar amounts, had no significant effect on the parameters measured. These data suggest that the rat counterpart of mouse Crry/p65 plays a vital role in vivo by preventing the activation of autologous complement on vascular endothelium.

1994-01-01

208

Artemisia scoparia Enhances Adipocyte Development and Endocrine Function In Vitro and Enhances Insulin Action In Vivo  

PubMed Central

Background Failure of adipocytes to expand during periods of energy excess can result in undesirable metabolic consequences such as ectopic fat accumulation and insulin resistance. Blinded screening studies have indicated that Artemisia scoparia (SCO) extracts can enhance adipocyte differentiation and lipid accumulation in cultured adipocytes. The present study tested the hypothesis that SCO treatment modulates fat cell development and function in vitro and insulin sensitivity in adipose tissue in vivo. Methods In vitro experiments utilized a Gal4-PPAR? ligand binding domain (LBD) fusion protein-luciferase reporter assay to examine PPAR? activation. To investigate the ability of SCO to modulate adipogenesis and mature fat cell function in 3T3-L1 cells, neutral lipid accumulation, gene expression, and protein secretion were measured by Oil Red O staining, qRT-PCR, and immunoblotting, respectively. For the in vivo experiments, diet-induced obese (DIO) C57BL/6J mice were fed a high-fat diet (HFD) or HFD containing 1% w/w SCO for four weeks. Body weight and composition, food intake, and fasting glucose and insulin levels were measured. Phospho-activation and expression of insulin-sensitizing proteins in epididymal adipose tissue (eWAT) were measured by immunoblotting. Results Ethanolic extracts of A. scoparia significantly activated the PPAR? LBD and enhanced lipid accumulation in differentiating 3T3-L1 cells. SCO increased the transcription of several PPAR? target genes in differentiating 3T3-L1 cells and rescued the negative effects of tumor necrosis factor ? on production and secretion of adiponectin and monocyte chemoattractant protein-1 in fully differentiated fat cells. DIO mice treated with SCO had elevated adiponectin levels and increased phosphorylation of AMPK? in eWAT when compared to control mice. In SCO-treated mice, these changes were also associated with decreased fasting insulin and glucose levels. Conclusion SCO has metabolically beneficial effects on adipocytes in vitro and adipose tissue in vivo, highlighting its potential as a metabolically favorable botanical supplement.

Richard, Allison J.; Fuller, Scott; Fedorcenco, Veaceslav; Beyl, Robbie; Burris, Thomas P.; Mynatt, Randall; Ribnicky, David M.; Stephens, Jacqueline M.

2014-01-01

209

Functional Data Analysis in Brain Imaging Studies  

PubMed Central

Functional data analysis (FDA) considers the continuity of the curves or functions, and is a topic of increasing interest in the statistics community. FDA is commonly applied to time-series and spatial-series studies. The development of functional brain imaging techniques in recent years made it possible to study the relationship between brain and mind over time. Consequently, an enormous amount of functional data is collected and needs to be analyzed. Functional techniques designed for these data are in strong demand. This paper discusses three statistically challenging problems utilizing FDA techniques in functional brain imaging analysis. These problems are dimension reduction (or feature extraction), spatial classification in functional magnetic resonance imaging studies, and the inverse problem in magneto-encephalography studies. The application of FDA to these issues is relatively new but has been shown to be considerably effective. Future efforts can further explore the potential of FDA in functional brain imaging studies.

Tian, Tian Siva

2010-01-01

210

APL functions for interactive data analysis: Principal components analysis  

Microsoft Academic Search

APL functions to support principal components analysis are presented: a general-purpose function to obtain eigen values and\\u000a eigen vectors, a more specialized function to convert these into the results commonly given by principal components analysis,\\u000a and a user interface function that accesses filed data, offers flexibility in data selection, and produces labeled output.\\u000a A brief introduction to the logic and

Selby Evans; Jerry D. Neideffer; Fred H. Gage

1981-01-01

211

Ex vivo magnetofection: A novel strategy for the study of gene function in mouse organogenesis  

PubMed Central

Gene function during mouse development is often studied through the production and analysis of transgenic and knock-out models. However, these techniques are time- and resource-consuming, and require specialized equipment and expertise. We have established a new protocol for functional studies that combines organ culture of explanted fetal tissues with micro-injection and magnetically-induced transfection (“magnetofection”) of gene expression constructs. As proof-of-principle, we magnetofected cDNA constructs into genital ridge tissue as a means of gain-of-function analysis, and shRNA constructs for loss-of-function analysis. Ectopic expression of Sry induced female-to-male sex-reversal, whereas knockdown of Sox9 expression caused male-to-female sex-reversal, consistent with the known functions of these genes. Further, ectopic expression of Tmem184a, a gene of unknown function, in female genital ridges, resulted in failure of gonocytes to enter meiosis. This technique will likely be applicable to the study of gene function in a broader range of developing organs and tissues.

Svingen, Terje; Wilhelm, Dagmar; Combes, Alexander N.; Hosking, Brett; Harley, Vincent R.; Sinclair, Andrew H.; Koopman, Peter

2010-01-01

212

In vivo optogenetic tracing of functional corticocortical connections between motor forelimb areas  

PubMed Central

Interactions between distinct motor cortical areas are essential for coordinated motor behaviors. In rodents, the motor cortical forelimb areas are divided into at least two distinct areas: the rostral forelimb area (RFA) and the caudal forelimb area (CFA). The RFA is thought to be an equivalent of the premotor cortex (PM) in primates, whereas the CFA is believed to be an equivalent of the primary motor cortex. Although reciprocal connections between the RFA and the CFA have been anatomically identified in rats, it is unknown whether there are functional connections between these areas that can induce postsynaptic spikes. In this study, we used an in vivo Channelrhodopsin-2 (ChR2) photostimulation method to trace the functional connections between the mouse RFA and CFA. Simultaneous electrical recordings were utilized to detect spiking activities induced by synaptic inputs originating from photostimulated areas. This method, in combination with anatomical tracing, demonstrated that the RFA receives strong functional projections from layer 2/3 and/or layer 5a, but not from layer 5b (L5b), of the CFA. Further, the CFA receives strong projections from L5b neurons of the RFA. The onset latency of electrical responses evoked in remote areas upon photostimulation of the other areas was approximately 10 ms, which is consistent with the synaptic connectivity between these areas. Our results suggest that neuronal activities in the RFA and the CFA during movements are formed through asymmetric reciprocal connections.

Hira, Riichiro; Ohkubo, Fuki; Tanaka, Yasuhiro R.; Masamizu, Yoshito; Augustine, George J.; Kasai, Haruo; Matsuzaki, Masanori

2013-01-01

213

Reconstruction of functional endometrium-like tissue in vitro and in vivo using cell sheet engineering.  

PubMed

Uterus is a female specific reproductive organ and plays critical roles in allowing embryo to grow. Therefore, the endometrial disorders lead to female infertility. Hence, the regeneration of endometrium allowing fertilized ovum to implant might be valuable in the field of fertility treatment. Recently, cell sheet engineering using a temperature-responsive culture dish has advanced in regenerative medicine. With this technology, endometrial cells were harvested as a contiguous cell sheet by reducing temperature. Firstly, mouse endometrial cell sheets were re-cultured for 3 days to evaluate the function. Histological analyses revealed that endometrial epithelial cell-specific cytokeratin 18 and female-specific hormone receptors, estrogen receptor ? and progesterone receptor, were expressed. Furthermore, endometrial epithelial cells constructed epithelial layer at the apical side. Then, endometrial cell sheets from green-fluorescent-protein rat cells were transplanted onto the buttock muscle of nude rat for evaluating the function in vivo. Histological analyses showed that endometrial cell sheets reconstructed endometrium-like tissue, which was found to form uterus-specific endometrial glands having hormonal receptor to estrogen. In this study, endometrial cell sheets were speculated to contribute to the regeneration of functional endometrium as a new therapy. PMID:24602616

Takagi, Soichi; Shimizu, Tatsuya; Kuramoto, Goro; Ishitani, Ken; Matsui, Hideo; Yamato, Masayuki; Okano, Teruo

2014-03-28

214

Doxycycline's Effect on Ocular Angiogenesis: an In Vivo Analysis  

PubMed Central

Purpose To determine the in vivo effect of doxycycline (doxy) on choroidal angiogenesis and pterygium growth by using a choroidal neovascular murine model (CNV), a directed in vivo angiogenesis assay (DIVAA) and a pterygium murine model. Design Experimental Study Participants 3 murine models were investigated with 4 mice minimum per group and 22 maximum per group. Methods Mice received water with or without doxycycline (Leiter's Pharmacy, San Jose, CA). For the CNV, the neovascular lesion volume was determined in choroid-retinal pigment epithelial (RPE) flat mounts using confocal microscopy seven days after laser induction. For DIVAA, silicone capsules containing 10,000 human pterygium epithelial cells were implanted in the flanks of mice subcutaneously. After eleven days, neovascularization (NV) was quantified using spectrofluorimetry after murine tail-vein injection of fluorescein isothiocyanate (FITC)-labeled dextran. A pterygium epithelial cell model was developed by injecting 10,000 human pterygium epithelial cells in the nasal subconjunctival space in athymic nude mice. Doxy was started on day six at 50 mg/kg/day; corneal lesions that resulted from the injections were compared at days six and fifteen. Main outcome measures Student's t-test was used to evaluate the data for the CNV and DIVAA models and histologic preparations were used to evaluate pterygia lesions. Results There was significantly less NV and lesion volume with doxy taken in drinking water versus plain water. With doxy treatment, the laser-induced CNV showed a maximal 66% decrease in choroidal blood vessel volume (p?0.008) and the DIVAA showed a 30% reduction of blood vessel growth and migration (p<0.004). Histologic preparations demonstrated that pterygium cell lesions regressed when mice were administered doxy for 9 days. Conclusions Doxycycline significantly inhibited angiogenesis in three murine models. The most dramatic effect was found in the choroidal neovascularization model followed by the pterygia epithelial cell DIVAA model. The anterior segment pterygium model also showed regression histologically. This suggests that doxycycline may be successful as an adjunctive treatment for choroidal neovascularization and pterygia in humans; clinical trials would be necessary to determine if there is a benefit.

Cox, Constance A.; Amaral, Juan; Salloum, Rita; Guedez, Liliana; Reid, Ted W.; Jaworski, Cindy; John-Aryankalayil, Moly; Freedman, Ken A.; Campos, Mercedes M.; Martinez, Alfredo; Becerra, S. Patricia; Carper, Deborah A.

2010-01-01

215

Energy function analysis for power system stability  

Microsoft Academic Search

Energy Function Analysis for Power System Stability presents the concept of energy function, which has found wide-spread applications for power systems in recent years. The most recent advances in five distinct areas are reviewed: Development of energy functions for structure preserving models, which can incorporate non-linear load models; energy functions which include a detailed model of the generating unit (i.e.

M. A. Pai

1989-01-01

216

Relationship between in vitro sperm functional tests and in vivo fertility of rams following cervical artificial insemination of ewes with frozen-thawed semen.  

PubMed

Several procedures have been proposed to assess structural and functional characteristics of cryopreserved ram semen but none so far have yielded consistent relationships with in vivo fertility. The objectives of this study were to evaluate several sperm function tests as potential markers of in vivo ram fertility (determined by pregnancy rate in ewes) using frozen-thawed semen. In experiment 1, frozen-thawed straws (n=3 per ram) of semen from three high and three low fertility rams were assessed using fluorescent microscopy for (1) progressive motility, (2) viability and, (3) acrosomal status. In experiment 2, frozen-thawed straws (n=3 per ram) of semen from 18 rams of known fertility were analysed using either computer-assisted sperm analysis (CASA) for eight motion characteristics or flow cytometric staining for: (1) viability and acrosomal status, (2) plasma membrane status and capacitation-like changes, and (3) live cells following an osmotic resistance test (ORT). In experiment 3, platelet-activating factor (PAF) was isolated from straws (n=2 per ram) of semen using high-pressure liquid chromatography (HPLC) and quantified using HPLC-tandem mass spectrometry for 18 rams. In experiment 1, no association was found between motility, viability (% live) or acrosomal status (% damaged, % intact and % reacted) and in vivo fertility. In experiment 2, no correlation was found between motility (CASA), viability (% live), acrosomal status (% live, % live intact and % reacted), capacitation status (% capacitated, % non-capacitated), plasma membrane stability (% dead) and % live cells following ORT and ram in vivo fertility. In experiment 3, there was no relationship between PAF content in spermatozoa and ram fertility. In conclusion, we were unable to relate the in vivo fertility of rams with in vitro functional tests of their frozen-thawed semen and suggest that the fertility of a given semen sample cannot easily be quantified using available in vitro tests. PMID:18248736

O' Meara, C M; Hanrahan, J P; Prathalingam, N S; Owen, J S; Donovan, A; Fair, S; Ward, F; Wade, M; Evans, A C O; Lonergan, P

2008-03-01

217

Us3, a multifunctional protein kinase encoded by herpes simplex virus 1: how does it function in vivo?  

PubMed

Phosphorylation is a common protein modification by which a cell or virus regulates protein activity, and subsequently cellular and viral functions. Herpesviruses commonly encode protein kinases that regulate their own replicative processes and modify host cellular machinery, by phosphorylating target proteins. Although numerous studies have revealed the multiple downstream effects of viral protein kinases and their potential molecular mechanisms, it remains unknown whether herpes viral protein kinases are involved in viral replication and pathogenicity in vivo. This review focuses on Us3 protein kinase encoded by herpes simplex virus 1 and provides a current overview of its functions in infected cells, with a special focus on their relevancy in vivo. PMID:24104928

Kawaguchi, Yasushi

2013-11-01

218

Multivariate analysis of functional metagenomes.  

PubMed

Metagenomics is a primary tool for the description of microbial and viral communities. The sheer magnitude of the data generated in each metagenome makes identifying key differences in the function and taxonomy between communities difficult to elucidate. Here we discuss the application of seven different data mining and statistical analyses by comparing and contrasting the metabolic functions of 212 microbial metagenomes within and between 10 environments. Not all approaches are appropriate for all questions, and researchers should decide which approach addresses their questions. This work demonstrated the use of each approach: for example, random forests provided a robust and enlightening description of both the clustering of metagenomes and the metabolic processes that were important in separating microbial communities from different environments. All analyses identified that the presence of phage genes within the microbial community was a predictor of whether the microbial community was host-associated or free-living. Several analyses identified the subtle differences that occur with environments, such as those seen in different regions of the marine environment. PMID:23579547

Dinsdale, Elizabeth A; Edwards, Robert A; Bailey, Barbara A; Tuba, Imre; Akhter, Sajia; McNair, Katelyn; Schmieder, Robert; Apkarian, Naneh; Creek, Michelle; Guan, Eric; Hernandez, Mayra; Isaacs, Katherine; Peterson, Chris; Regh, Todd; Ponomarenko, Vadim

2013-01-01

219

Sensitivity analysis of near-infrared functional lymphatic imaging  

NASA Astrophysics Data System (ADS)

Near-infrared imaging of lymphatic drainage of injected indocyanine green (ICG) has emerged as a new technology for clinical imaging of lymphatic architecture and quantification of vessel function, yet the imaging capabilities of this approach have yet to be quantitatively characterized. We seek to quantify its capabilities as a diagnostic tool for lymphatic disease. Imaging is performed in a tissue phantom for sensitivity analysis and in hairless rats for in vivo testing. To demonstrate the efficacy of this imaging approach to quantifying immediate functional changes in lymphatics, we investigate the effects of a topically applied nitric oxide (NO) donor glyceryl trinitrate ointment. Premixing ICG with albumin induces greater fluorescence intensity, with the ideal concentration being 150 ?g/mL ICG and 60 g/L albumin. ICG fluorescence can be detected at a concentration of 150 ?g/mL as deep as 6 mm with our system, but spatial resolution deteriorates below 3 mm, skewing measurements of vessel geometry. NO treatment slows lymphatic transport, which is reflected in increased transport time, reduced packet frequency, reduced packet velocity, and reduced effective contraction length. NIR imaging may be an alternative to invasive procedures measuring lymphatic function in vivo in real time.

Weiler, Michael; Kassis, Timothy; Dixon, J. Brandon

2012-06-01

220

Sensitivity analysis of near-infrared functional lymphatic imaging.  

PubMed

Near-infrared imaging of lymphatic drainage of injected indocyanine green (ICG) has emerged as a new technology for clinical imaging of lymphatic architecture and quantification of vessel function, yet the imaging capabilities of this approach have yet to be quantitatively characterized. We seek to quantify its capabilities as a diagnostic tool for lymphatic disease. Imaging is performed in a tissue phantom for sensitivity analysis and in hairless rats for in vivo testing. To demonstrate the efficacy of this imaging approach to quantifying immediate functional changes in lymphatics, we investigate the effects of a topically applied nitric oxide (NO) donor glyceryl trinitrate ointment. Premixing ICG with albumin induces greater fluorescence intensity, with the ideal concentration being 150 ?g/mL ICG and 60 g/L albumin. ICG fluorescence can be detected at a concentration of 150 ?g/mL as deep as 6 mm with our system, but spatial resolution deteriorates below 3 mm, skewing measurements of vessel geometry. NO treatment slows lymphatic transport, which is reflected in increased transport time, reduced packet frequency, reduced packet velocity, and reduced effective contraction length. NIR imaging may be an alternative to invasive procedures measuring lymphatic function in vivo in real time. PMID:22734775

Weiler, Michael; Kassis, Timothy; Dixon, J Brandon

2012-06-01

221

A tissue adhesives evaluated in vitro and in vivo analysis.  

PubMed

In this study, three kinds of two-component adhesive glues were prepared, namely, gel-dext glue made from modified gelatin and dextran, gel-HES glue made from modified gelatin and hydroxyethyl starch (HES), and chit-dext glue made from chitosan and modified dextran. Upon mixing the two-component solution together crosslinking occurred and a gel formed in several seconds, which would seal the wound tissue and stop the bleeding. The adhesive ability of those three prepared glues was evaluated in vitro and in vivo separately by measuring the bonding strength to two piece of porcine skin and the adhesive strength after sealing the skin incisions on the back of rat. Fibrin glue was used as comparing. Gel-dext glue and gel-HES glue shown higher bonding strength and adhesive strength than chit-dext glue and fibrin glue. Histology test of incision tissues given by both HE and MTC methods, the former shown that gel-dext and gel-HES glues, like fibrin glue, have only normal initial inflammation to skin tissue, which almost disappear from 9 days but chit-dext glue seams have heaver inflammation, which may last to 12 days; the later shown gel-dext and gel-HES glues similar to fibrin glue, can heal the wound fast than that of chit-dext glue. The hemostatic ability for gel-HES glue was also tested on a cut liver of rat, which depend on the gel formation speed when the two-composite solutions were mixed together. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010. PMID:20496438

Mo, Xiumei; Iwata, Hiroo; Ikada, Yoshito

2010-07-01

222

Conditional gene deletion reveals functional redundancy of GABAB receptors in peripheral nociceptors in vivo  

PubMed Central

Background ?-aminobutyric acid (GABA) is an important inhibitory neurotransmitter which mainly mediates its effects on neurons via ionotropic (GABAA) and metabotropic (GABAB) receptors. GABAB receptors are widely expressed in the central and the peripheral nervous system. Although there is evidence for a key function of GABAB receptors in the modulation of pain, the relative contribution of peripherally- versus centrally-expressed GABAB receptors is unclear. Results In order to elucidate the functional relevance of GABAB receptors expressed in peripheral nociceptive neurons in pain modulation we generated and analyzed conditional mouse mutants lacking functional GABAB(1) subunit specifically in nociceptors, preserving expression in the spinal cord and brain (SNS-GABAB(1)-/- mice). Lack of the GABAB(1) subunit precludes the assembly of functional GABAB receptor. We analyzed SNS-GABAB(1)-/- mice and their control littermates in several models of acute and neuropathic pain. Electrophysiological studies on peripheral afferents revealed higher firing frequencies in SNS-GABAB(1)-/- mice compared to corresponding control littermates. However no differences were seen in basal nociceptive sensitivity between these groups. The development of neuropathic and chronic inflammatory pain was similar across the two genotypes. The duration of nocifensive responses evoked by intraplantar formalin injection was prolonged in the SNS-GABAB(1)-/- animals as compared to their control littermates. Pharmacological experiments revealed that systemic baclofen-induced inhibition of formalin-induced nociceptive behaviors was not dependent upon GABAB(1) expression in nociceptors. Conclusion This study addressed contribution of GABAB receptors expressed on primary afferent nociceptive fibers to the modulation of pain. We observed that neither the development of acute and chronic pain nor the analgesic effects of a systematically-delivered GABAB agonist was significantly changed upon a specific deletion of GABAB receptors from peripheral nociceptive neurons in vivo. This lets us conclude that GABAB receptors in the peripheral nervous system play a less important role than those in the central nervous system in the regulation of pain.

2009-01-01

223

Human Retinal Pigment Epithelium Cells as Functional Models for the RPE In Vivo  

PubMed Central

Purpose. The two most commonly used in vitro models of the retinal pigment epithelium (RPE) are fetal human RPE (fhRPE) and ARPE-19 cells; however, studies of their barrier properties have produced contradictory results. To compare their utility as RPE models, their morphologic and functional characteristics were analyzed. Methods. Monolayers of both cell types were grown on permeable membrane filters. Barrier function and cellular morphology were assessed by transepithelial resistance (TER) measurements and immunohistochemistry. Protein expression was evaluated by immunoblotting and ELISA assays, and retinoid metabolism characterized by HPLC. Results. Both cultures developed tight junctions. However, only the fhRPE cells were pigmented, uniform in size and shape, expressed high levels of RPE markers, metabolized all-trans retinal, and developed high TER (>400 ?cm2). The net secretion of pigment-epithelium-derived factor (PEDF) was directed apically in both cultures, but fhRPE cells exhibited secretion rates a thousand-fold greater than in ARPE-19 cells. The net secretion of vascular endothelial growth factor (VEGF) was significantly higher in fhRPE cultures and the direction of this secretion was basolateral; while net secretion was apical in ARPE-19 cells. In fresh media, VEGF-E reduced TER in both cultures; however, in conditioned media fhRPE cells did not respond to VEGF-E administration, but retreatment of the conditioned media with anti-PEDF antibodies allowed fhRPE cells to fully respond to VEGF-E. Conclusions. Properties of fhRPE cells align with a functionally normal RPE in vivo, while ARPE-19 cells resemble a pathologic or aged RPE. These results suggest a utility for both cell types in understanding distinct, particular aspects of RPE function.

Dahrouj, Mohammad; Tang, Peter H.; Liu, Yueying; Sambamurti, Kumar; Marmorstein, Alan D.; Crosson, Craig E.

2011-01-01

224

Functional Changes in Neocortical Activity in Huntington's Disease Model Mice: An in vivo Intracellular Study  

PubMed Central

Studies of animal models of Huntington's disease (HD) have revealed that neocortical and neostriatal neurons of these animals in vitro exhibit a number of morphological and physiological changes, including increased input resistance and changes in neocortical synaptic inputs. We measured the functional effects of polyglutamate accumulation in neocortical neurons in R6/2 mice (8–14 weeks of age) and their age-matched non-transgenic littermates using in vivo intracellular recordings. All neurons showed spontaneous membrane potential fluctuations. The current/voltage and the firing properties of the HD neocortical neurons were significantly altered, especially in the physiologically relevant current range around and below threshold. As a result, membrane potential transitions from the Down state to Up state were evoked with smaller currents in HD neocortical neurons than in controls. The excitation-to-frequency curves of the HD mice were significantly steeper than those of controls, indicating a smaller input–output dynamic range for these neurons. Increased likelihood of Down to Up state transitions could cause pathological recruitment of corticostriatal assemblies by increasing correlated neuronal activity. We measured coherence of the in vivo intracellular recordings with simultaneously recorded electrocorticograms. We found that the peak of the coherence at <5?Hz was significantly smaller in the HD animals, indicating that the amount of coherence in the state transitions of single neurons is less correlated with global activity than non-transgenic controls. We propose that decreased correlation of neocortical inputs may be a major physiological cause underlying the errors in sensorimotor pattern generation in HD.

Stern, Edward A.

2011-01-01

225

In vivo perturbation of rat hepatocyte canalicular membrane function by diclofenac.  

PubMed

Clinical use of diclofenac is associated with a small but significant incidence of hepatotoxicity. It has been reported that in vivo diclofenac treatment results in decreased activity of the extracellular canalicular membrane protein dipeptidylpeptidase IV in rats as a consequence of protein adduct formation by its electrophilic metabolite diclofenac acyl glucuronide. The present study has investigated the effects of in vivo diclofenac treatment (15 mg/kg/day for 7 days) on the activity of an another four rat extracellular canalicular membrane proteins. Animals administered diclofenac (n = 6) had 47.9, 60.4, and 51.6% lower (p < 0.05) canalicular activities of gamma-glutamyltransferase, Mg(2+)-ATPase, and leucine aminopeptidase, respectively, compared with controls (n = 6), but there was no difference in alkaline phosphatase activity. In general, protein adduct formation by acyl glucuronides has been associated with decreased protein function, and the lower canalicular enzyme activities in diclofenac-treated rats may suggest that gamma-glutamyltransferase, Mg(2+)-ATPase, and leucine aminopeptidase are also targets of adduct formation by acyl glucuronide metabolites of diclofenac. However, intracellular redistribution and/or decreased synthesis of these enzymes would also be consistent with our results. The ability of diclofenac acyl glucuronide (200 microg/ml) to form covalently bound adducts with gamma-glutamyltransferase (10 mg/ml) was demonstrated following in vitro incubations (16 h, pH 7.4, and 37 degrees C) in which 20.7 +/- 2.1 ng of diclofenac were covalently bound per milligram of protein. In these in vitro studies, the low concentration of protein adducts formed was not associated with any significant change in gamma-glutamyltransferase activity. PMID:11717171

Sallustio, B C; Holbrook, F L

2001-12-01

226

Impact of hydrogel nanoparticle size and functionalization on in vivo behavior for lung imaging and therapeutics  

PubMed Central

Polymer chemistry offers the possibility of synthesizing multifunctional nanoparticles which incorporate moieties that enhance diagnostic and therapeutic targeting of cargo delivery to the lung. However, since rules for predicting particle behavior following modification are not well defined, it is essential that probes for tracking fate in vivo are also included. Accordingly, we designed polyacrylamide-based hydrogel particles of differing sizes, functionalized with a nona-arginine cell-penetrating peptide (Arg9), and labeled with imaging components to assess lung retention and cellular uptake after intratracheal administration. Radiolabeled microparticles (1–5 µm diameter) and nanoparticles (20–40 nm diameter) without and with Arg9 showed diffuse airspace distribution by positron emission tomography imaging. Biodistribution studies revealed that particle clearance and extrapulmonary distribution was, in part, size dependent. Microparticles were rapidly cleared by mucociliary routes but unexpectedly, also through the circulation. In contrast, nanoparticles had prolonged lung retention enhanced by Arg9 and were significantly restricted to the lung. For all particle types, uptake was predominant in alveolar macrophages, and, to a lesser extent, lung epithelial cells. In general, particles did not induce local inflammatory responses, with the exception of microparticles bearing Arg9. Whereas microparticles may be advantageous for short-term applications, nano-sized particles constitute an efficient high-retention and non-inflammatory vehicle for the delivery of diagnostic imaging agents and therapeutics to lung airspaces and alveolar macrophages that can be enhanced by Arg9. Importantly, our results show that minor particle modifications may significantly impact in vivo behavior within the complex environments of the lung, underscoring the need for animal modeling.

Liu, Yongjian; Ibricevic-Richardson, Aida; Cohen, Joel A.; Cohen, Jessica L.; Gunsten, Sean P.; Frechet, Jean M. J.; Walter, Michael J.; Welch, Michael J.; Brody, Steven L.

2009-01-01

227

Group I PAKs function downstream of Rac to promote podosome invasion during myoblast fusion in vivo  

PubMed Central

The p21-activated kinases (PAKs) play essential roles in diverse cellular processes and are required for cell proliferation, apoptosis, polarity establishment, migration, and cell shape changes. Here, we have identified a novel function for the group I PAKs in cell–cell fusion. We show that the two Drosophila group I PAKs, DPak3 and DPak1, have partially redundant functions in myoblast fusion in vivo, with DPak3 playing a major role. DPak3 is enriched at the site of fusion colocalizing with the F-actin focus within a podosome-like structure (PLS), and promotes actin filament assembly during PLS invasion. Although the small GTPase Rac is involved in DPak3 activation and recruitment to the PLS, the kinase activity of DPak3 is required for effective PLS invasion. We propose a model whereby group I PAKs act downstream of Rac to organize the actin filaments within the PLS into a dense focus, which in turn promotes PLS invasion and fusion pore initiation during myoblast fusion.

Duan, Rui; Jin, Peng; Luo, Fengbao; Zhang, Guofeng; Anderson, Nathan

2012-01-01

228

Conserved Fate and Function of Ferumoxides-Labeled Neural Precursor Cells In Vitro and In Vivo  

PubMed Central

Recent progress in cell therapy research for brain diseases has raised the need for non-invasive monitoring of transplanted cells. For therapeutic application in multiple sclerosis, transplanted cells need to be tracked both spatially and temporally, in order to assess their migration and survival in the host tissue. Magnetic resonance imaging (MRI) of superparamagnetic iron oxide-(SPIO)-labeled cells has been widely used for high resolution monitoring of the biodistribution of cells after transplantation into the central nervous system (CNS). Here we labeled mouse glial-committed neural precursor cells (NPCs) with the clinically approved SPIO contrast agent ferumoxides and examined their survival and differentiation in vitro, as well as their functional response to environmental signals present within the inflamed brain of experimental autoimmune encephalomyelitis (EAE) mice in vivo. We show that ferumoxides labeling does not affect NPC survival and pluripotency in vitro. Following intracerebroventricular (ICV) transplantation in EAE mice, ferumoxides-labeled NPCs responded to inflammatory cues in a similar fashion as unlabeled cells. Ferumoxides-labeled NPCs migrated over comparable distances in white matter tracts and differentiated equally into the glial lineages. Furthermore, ferumoxides-labeled NPCs inhibited lymph node cell proliferation in vitro, similarly to non-labeled cells, suggesting a preserved immunomodulatory function. These results demonstrate that ferumoxides-based MRI cell tracking is well suited for non-invasive monitoring of NPC transplantation.

Cohen, Mikhal E.; Muja, Naser; Fainstein, Nina; Bulte, Jeff W.M.; Ben-Hur, Tamir

2011-01-01

229

Polyglycerolsulfate functionalized gold nanorods as optoacoustic signal nanoamplifiers for in vivo bioimaging of rheumatoid arthritis.  

PubMed

We have synthesized a targeted imaging agent for rheumatoid arthritis based on polysulfated gold nanorods. The CTAB layer on gold nanorods was first replaced with PEG-thiol and then with dendritic polyglycerolsulfate at elevated temperature, which resulted in significantly reduced cytotoxicity compared to polyanionic gold nanorods functionalized by non-covalent approaches. In addition to classical characterization methods, we have established a facile UV-VIS based BaCl2 agglomeration assay to confirm a quantitative removal of unbound ligand. With the help of a competitive surface plasmon resonance-based L-selectin binding assay and a leukocyte adhesion-based flow cell assay, we have demonstrated the high inflammation targeting potential of the synthesized gold nanorods in vitro. In combination with the surface plasmon resonance band of AuNRs at 780 nm, these findings permitted the imaging of inflammation in an in vivo mouse model for rheumatoid arthritis with high contrast using multispectral optoacoustic tomography. The study offers a robust method for otherwise difficult to obtain covalently functionalized polyanionic gold nanorods, which are suitable for biological applications as well as a low-cost, actively targeted, and high contrast imaging agent for the diagnosis of rheumatoid arthritis. This paves the way for further research in other inflammation associated pathologies, in particular, when photothermal therapy can be applied. PMID:24723984

Vonnemann, Jonathan; Beziere, Nicolas; Böttcher, Christoph; Riese, Sebastian B; Kuehne, Christian; Dernedde, Jens; Licha, Kai; von Schacky, Claudio; Kosanke, Yvonne; Kimm, Melanie; Meier, Reinhard; Ntziachristos, Vasilis; Haag, Rainer

2014-01-01

230

Tolerogenic Function of Dimeric Forms of HLA-G Recombinant Proteins: A Comparative Study In Vivo  

PubMed Central

HLA-G is a natural tolerogenic molecule involved in the best example of tolerance to foreign tissues there is: the maternal-fetal tolerance. The further involvement of HLA-G in the tolerance of allogeneic transplants has also been demonstrated and some of its mechanisms of action have been elucidated. For these reasons, therapeutic HLA-G molecules for tolerance induction in transplantation are actively investigated. In the present study, we studied the tolerogenic functions of three different HLA-G recombinant proteins: HLA-G heavy chain fused to ?2-microglobulin (B2M), HLA-G heavy chain fused to B2M and to the Fc portion of an immunoglobulin, and HLA-G alpha-1 domain either fused to the Fc part of an immunoglobulin or as a synthetic peptide. Our results demonstrate the tolerogenic function of B2M-HLA-G fusion proteins, and especially of B2M-HLA-G5, which were capable of significantly delaying allogeneic skin graft rejection in a murine in vivo transplantation model. The results from our studies suggest that HLA-G recombinant proteins are relevant candidates for tolerance induction in human transplantation.

Caumartin, Julien; Daouya, Marina; Horuzsko, Anatolij; Carosella, Edgardo D.; LeMaoult, Joel

2011-01-01

231

Twins, quadruplexes, and more: functional aspects of native and engineered RNA self-assembly in vivo  

PubMed Central

The primacy and power of RNA in governing many processes of life has begun to be more fully appreciated in both the discovery and inventive sciences. A variety of RNA interactions regulate gene expression, and structural self-assembly underlies many of these processes. The understanding sparked by these discoveries has inspired and informed the engineering of novel RNA structures, control elements, and genetic circuits in cells. Many of these engineered systems are built up fundamentally from RNA–RNA interactions, often combining modular, rational design with functional selection and screening. It is therefore useful to review the particular class of RNA-based regulatory mechanisms that rely on RNA self-assembly either through homomeric (self–self) or heteromeric (self–nonself) RNA–RNA interactions. Structures and sequence elements within individual RNAs create a basis for the pairing interactions, and in some instances can even lead to the formation of RNA polymers. Example systems of dimers, multimers, and polymers are reviewed in this article in the context of natural systems, wherein the function and impact of self-assemblies are understood. Following this, a brief overview is presented of specific engineered RNA self-assembly systems implemented in vivo, with lessons learned from both discovery and engineering approaches to RNA–RNA self-assembly.

Lease, Richard A.; Arluison, Veronique; Lavelle, Christophe

2013-01-01

232

Caspase inhibitors promote vestibular hair cell survival and function after aminoglycoside treatment in vivo  

NASA Technical Reports Server (NTRS)

The sensory hair cells of the inner ear undergo apoptosis after acoustic trauma or aminoglycoside antibiotic treatment, causing permanent auditory and vestibular deficits in humans. Previous studies have demonstrated a role for caspase activation in hair cell death and ototoxic injury that can be reduced by concurrent treatment with caspase inhibitors in vitro. In this study, we examined the protective effects of caspase inhibition on hair cell death in vivo after systemic injections of aminoglycosides. In one series of experiments, chickens were implanted with osmotic pumps that administrated the pan-caspase inhibitor z-Val-Ala-Asp(Ome)-fluoromethylketone (zVAD) into inner ear fluids. One day after the surgery, the animals received a 5 d course of treatment with streptomycin, a vestibulotoxic aminoglycoside. Direct infusion of zVAD into the vestibule significantly increased hair cell survival after streptomycin treatment. A second series of experiments determined whether rescued hair cells could function as sensory receptors. Animals treated with streptomycin displayed vestibular system impairment as measured by a greatly reduced vestibulo-ocular response (VOR). In contrast, animals that received concurrent systemic administration of zVAD with streptomycin had both significantly greater hair cell survival and significantly increased VOR responses, as compared with animals treated with streptomycin alone. These findings suggest that inhibiting the activation of caspases promotes the survival of hair cells and protects against vestibular function deficits after aminoglycoside treatment.

Matsui, Jonathan I.; Haque, Asim; Huss, David; Messana, Elizabeth P.; Alosi, Julie A.; Roberson, David W.; Cotanche, Douglas A.; Dickman, J. David; Warchol, Mark E.

2003-01-01

233

In VivoFunctional Imaging of Intrinsic Scattering Changes in the Human Retina with High-speed Ultrahigh Resolution OCT  

PubMed Central

Non-invasive methods of probing retinal function are of interest for the early detection of retinal disease. While retinal function is traditionally directly measured with the electroretinogram (ERG), recently functional optical imaging of the retina has been demonstrated. In this manuscript, stimulus-induced, intrinsic optical scattering changes in the human retina are measured in vivo with high-speed, ultrahigh resolution optical coherence tomography (OCT) operating at 50,000 axial scans per second and ?3.3 micron axial resolution. A stimulus and measurement protocol that enables measurement of functional OCT retinal signals is described. OCT signal changes in the photoreceptors are demonstrated. Two distinct responses having different temporal and spatial properties are reported. These results are discussed in the context of optical intrinsic signals measured previously in the retina by fundus imaging and scanning laser ophthalmoscopy. Finally, challenges associated with in vivo functional retinal imaging in human subjects are discussed.

Srinivasan, V. J.; Chen, Y.; Duker, J. S.; Fujimoto, J. G.

2009-01-01

234

Pyrimidine motif triple helix in the Kluyveromyces lactis telomerase RNA pseudoknot is essential for function in vivo.  

PubMed

Telomerase is a ribonucleoprotein complex that extends the 3' ends of linear chromosomes. The specialized telomerase reverse transcriptase requires a multidomain RNA (telomerase RNA, TER), which includes an integral RNA template and functionally important template-adjacent pseudoknot. The structure of the human TER pseudoknot revealed that the loops interact with the stems to form a triple helix shown to be important for activity in vitro. A similar triple helix has been predicted to form in diverse fungi TER pseudoknots. The solution NMR structure of the Kluyveromyces lactis pseudoknot, presented here, reveals that it contains a long pyrimidine motif triple helix with unexpected features that include three individual bulge nucleotides and a C(+)•G-C triple adjacent to a stem 2-loop 2 junction. Despite significant differences in sequence and base triples, the 3D shape of the human and K. lactis TER pseudoknots are remarkably similar. Analysis of the effects of nucleotide substitutions on cell growth and telomere lengths provides evidence that this conserved structure forms in endogenously assembled telomerase and is essential for telomerase function in vivo. PMID:23776224

Cash, Darian D; Cohen-Zontag, Osnat; Kim, Nak-Kyoon; Shefer, Kinneret; Brown, Yogev; Ulyanov, Nikolai B; Tzfati, Yehuda; Feigon, Juli

2013-07-01

235

Pyrimidine motif triple helix in the Kluyveromyces lactis telomerase RNA pseudoknot is essential for function in vivo  

PubMed Central

Telomerase is a ribonucleoprotein complex that extends the 3? ends of linear chromosomes. The specialized telomerase reverse transcriptase requires a multidomain RNA (telomerase RNA, TER), which includes an integral RNA template and functionally important template-adjacent pseudoknot. The structure of the human TER pseudoknot revealed that the loops interact with the stems to form a triple helix shown to be important for activity in vitro. A similar triple helix has been predicted to form in diverse fungi TER pseudoknots. The solution NMR structure of the Kluyveromyces lactis pseudoknot, presented here, reveals that it contains a long pyrimidine motif triple helix with unexpected features that include three individual bulge nucleotides and a C+•G-C triple adjacent to a stem 2–loop 2 junction. Despite significant differences in sequence and base triples, the 3D shape of the human and K. lactis TER pseudoknots are remarkably similar. Analysis of the effects of nucleotide substitutions on cell growth and telomere lengths provides evidence that this conserved structure forms in endogenously assembled telomerase and is essential for telomerase function in vivo.

Cash, Darian D.; Cohen-Zontag, Osnat; Kim, Nak-Kyoon; Shefer, Kinneret; Brown, Yogev; Ulyanov, Nikolai B.; Tzfati, Yehuda; Feigon, Juli

2013-01-01

236

The past, present, and future of x-ray technology for in vivo imaging of function and form  

SciTech Connect

Scientists and clinicians have a keen interest in studying not just the structure of physiological systems, but their motion also, or more generally their form and function. This paper focuses on the technologies that underpin in vivo measurements of form and function of the human body for both research and medical treatment. A concise literature review of x-ray imaging, ultrasonography, magnetic resonance imaging, radionuclide imaging, laser Doppler velocimetry, and particle image velocimetry is presented. Additionally, a more detailed review of in vivo x-ray imaging is presented. Finally, two techniques, which the authors believe are representative of the present and future of in vivo x-ray imaging techniques, are presented.

Fouras, A.; Dubsky, S.; Hourigan, K. [Division of Biological Engineering, Monash University, Clayton, Victoria 3800 (Australia) and Fluids Laboratory for Aeronautical and Industrial Research, Monash University, Clayton, Victoria 3800 (Australia); Kitchen, M. J. [School of Physics, Monash University, Clayton, Victoria 3800 (Australia); Lewis, R. A. [Monash Center for Synchrotron Science, Monash University, Clayton, Victoria 3800 (Australia); Hooper, S. B. [Department of Physiology, Monash University, Clayton, Victoria 3800 (Australia)

2009-05-15

237

Comprehensive processing, display and analysis forin vivo MR spectroscopic imaging  

Microsoft Academic Search

Image reconstruction for magnetic resonance spectroscopic imaging (MRSI) requires specialized spatial and spectral data processing methods and benefits from the use of several sources of prior information that are not commonly available, including MRI-derived tissue segmentation, morphological analysis and spectral characteristics of the observed metabolites. In addition, incorporating information obtained from MRI data can enhance the display of low-resolution metabolite

A. A. Maudsley; A. Darkazanli; J. R. Alger; L. O. Hall; N. Schuff; C. Studholme; Y. Yu; A. Ebel; A. Frew; D. Goldgof; Y. Gu; R. Pagare; F. Rousseau; K. Sivasankaran; B. J. Soher; P. Weber; K. Young; X. Zhu

2006-01-01

238

Identification of in-vivo vibration modes of human tibiae by modal analysis.  

PubMed

When attempting to evaluate the mechanical properties of human bones in vivo by mechanical vibration analysis, some essential requirements must be met. A quantitative relation between measured vibration parameters (e.g., natural frequency) and mechanical bone properties must be available, in-vivo vibration modes should correctly be identified and the associated natural frequencies reproducibly and accurately measured, the influence of joints and soft tissues must be known. These problems were addressed by modal analysis (i.e., experimental determination of natural frequencies, mode shapes and damping ratios) of human tibiae in the following situations: 1) dry excised tibiae, 2) fresh excised tibiae, 3) in-vivo tibiae, 4) tibiae in an amputated leg, in different steps of dissection. In the in-vivo measuring conditions used by the authors, the tibia vibration is practically free-free. Two single bending modes (at +/- 270 Hz and +/- 340 Hz, respectively), each of them corresponding with one principal direction for bending, were identified. The difference between the natural frequencies observed in vivo and those of fresh excised tibiae is almost completely caused by the effect of muscles (added mass and damping), whereas joints and skin play only a minor role. Frequency differences between fresh and dry excised tibiae are largely accounted for by the absence of bone marrow in the latter. PMID:6632826

Van der Perre, G; Van Audekercke, R; Martens, M; Mulier, J C

1983-08-01

239

In vivo XRF analysis of mercury: the relation between concentrations in the kidney and the urine  

Microsoft Academic Search

The objective of this study was to determine the concentrations of mercury in organs of occupationally exposed workers using in vivo X-ray fluorescence analysis. Twenty mercury exposed workers and twelve occupationally unexposed referents participated in the study. Their mercury levels in kidney, liver and thyroid were measured using a technique based on excitation with partly plane polarized photons. The mercury

J. Borjesson; L. Barregard; G. Sallsten; A. Schutz; R. Jonson; M. Alpsten; S. Mattsson

1995-01-01

240

Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions.  

PubMed

Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming-these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that 'soil engineering in vivo', wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon-effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized. PMID:20829246

DeJong, Jason T; Soga, Kenichi; Banwart, Steven A; Whalley, W Richard; Ginn, Timothy R; Nelson, Douglas C; Mortensen, Brina M; Martinez, Brian C; Barkouki, Tammer

2011-01-01

241

Reduced Sox9 function promotes heart valve calcification phenotypes in vivo  

PubMed Central

Rationale Calcification of heart valve structures is the most common form of valvular disease and is characterized by the appearance of bone-like phenotypes within affected structures. Despite the clinical significance, the underlying etiology of disease onset and progression is largely unknown and valve replacement remains the most effective treatment. The SRY-related transcription factor Sox9 is expressed in developing and mature heart valves, and its function is required for expression of cartilage-associated proteins, similar to its role in chondrogenesis. In addition to cartilage-associated defects, mice with reduced sox9 function develop skeletal bone prematurely, however the ability of sox9 deficiency to promote ectopic osteogenic phenotypes in heart valves has not been examined. Objective This study aims to determine the role of Sox9 in maintaining connective tissue homeostasis in mature heart valves using in vivo and in vitro approaches. Methods and Results Using histological and molecular analyses we report that Sox9fl/+;Col2a1-cre mice develop calcific lesions in heart valve leaflets from 3 months of age associated with increased expression of bone-related genes and activation of inflammation and matrix remodeling processes. Consistently, ectopic calcification is also observed following direct knockdown of Sox9 in heart valves in vitro. Further, we show that retinoic acid treatment in mature heart valves is sufficient to promote calcific processes in vitro, which can be attenuated by Sox9 overexpression. Conclusions This study provides insights into the molecular mechanisms of heart valve calcification and identifies reduced Sox9 function as a potential genetic basis for calcific valvular disease.

Peacock, Jacqueline D; Levay, Agata K; Gillaspie, Devin B; Tao, Ge; Lincoln, Joy

2010-01-01

242

Effect of Oxidixed Dextrans on Oxidative and Metabolic Function of Mouse Peritoneal Macrophages In Vitro and In Vivo  

Microsoft Academic Search

We compared the effects of dextrans with a molecular weight of 35 kDa oxidized by chemical (ODch) and radiochemical (ODr) methods on oxidative and metabolic functions of peritoneal macrophages from BALB\\/c mice in vitro and in vivo. It was found that none type of dextrans exhibits chemiluminescent properties. In vitro study showed that ODch had a priming effect on mouse

V. A. Shkurupiy; D. D. Tsyrendorzhiev; V. V. Kurilin; A. B. Troitskii; M. A. Saperova; E. A. Efanov; E. P. Gulyaeva; T. A. Parkhomenko

2008-01-01

243

An Analytical Model for Elucidating Tendon Tissue Structure and Biomechanical Function from in vivo Cellular Confocal Microscopy Images  

Microsoft Academic Search

Fibered confocal laser scanning microscopes have given us the ability to image fluorescently labeled biological struc- tures in vivo and at exceptionally high spatial resolutions. By coupling this powerful imaging modality with classic opti- cal elastography methods, we have developed novel tech- niques that allow us to assess functional mechanical integrity of soft biological tissues by measuring the movements of

J. G. Snedeker; G. Pelled; Y. Zilberman; A. Ben Arav; E. Huber; R. Müller; D. Gazit

2008-01-01

244

An Analytical Model for Elucidating Tendon Tissue Structure and Biomechanical Function from in vivo Cellular Confocal Microscopy Images  

Microsoft Academic Search

Fibered confocal laser scanning microscopes have given us the ability to image fluorescently labeled biological structures in vivo and at exceptionally high spatial resolutions. By coupling this powerful imaging modality with classic optical elastography methods, we have developed novel techniques that allow us to assess functional mechanical integrity of soft biological tissues by measuring the movements of cells in response

J. G. Snedeker; G. Pelled; Y. Zilberman; A. Ben Arav; E. Huber; R. Müller; D. Gazit

2009-01-01

245

In vivo Evaluation of the Stratum corneum Barrier Function in Blacks, Caucasians and Asians with Two Noninvasive Methods  

Microsoft Academic Search

This study compared in man the in vivo barrier function of stratum corneum in three racial groups: black, Caucasian and Asian, by two noninvasive technics. They were transepidermal water loss (TEWL) determination measured with an evaporimeter and laser Doppler velocimetry (LDV) to measure the lag time before the vasodilatation induced by application of methyl nicotinate (10 ?l of 0.5% solution

F. Kompaore; J. P. Marty; Ch. Dupont

1993-01-01

246

In vivo dissection of the Helicobacter pylori Fur regulatory circuit by genome-wide location analysis.  

PubMed

Iron homeostasis is particularly important in pathogenic bacteria, which need to compete with the host for this essential cofactor. In Helicobacter pylori, a causative agent of several gastric pathologies, iron uptake and storage genes are regulated at the transcriptional level by the ferric uptake regulator Fur. The regulatory circuit of Fur has recently come under focus because of an intimate interlink with a broader regulatory network governing metal homeostasis, acidic response, and virulence. To dissect the Fur regulatory circuit and identify in vivo targets of regulation, we developed a genome-wide location analysis protocol which allowed the identification of 200 genomic loci bound by Fur as well as the investigation of the binding efficiency of the protein to these loci in response to iron. Comparative analysis with transcriptomes of wild-type and fur deletion mutant strains allowed the distinction between targets associated with Fur regulation and genes indirectly influenced by the fur mutation. The Fur regulon includes 59 genes, 25 of which appear to be positively regulated. A case study conducted by primer extension analysis of two oppositely regulated genes, hpn2 and flaB, suggests that negative regulation as well as positive regulation occurs at the transcriptional level. Furthermore, the results revealed the existence of 13 Fur targeted loci within polycistronic operons, which were associated with transcript deregulation in the fur mutant strain. This study provides a systematic insight of Fur regulation at the genome-wide level in H. pylori and points to regulatory functions extending beyond the classical Fur repression paradigm. PMID:16788174

Danielli, Alberto; Roncarati, Davide; Delany, Isabel; Chiarini, Valentina; Rappuoli, Rino; Scarlato, Vincenzo

2006-07-01

247

Stimulus analysis of BetP activation under in vivo conditions.  

PubMed

The secondary active, Na(+) coupled glycine betaine carrier BetP from Corynebacterium glutamicum BetP was shown to harbor two different functions, transport catalysis (betaine uptake) and stimulus sensing, as well as activity regulation in response to hyperosmotic stress. By analysis in a reconstituted system, the rise in the cytoplasmic K(+) concentration was identified as a primary stimulus for BetP activation. We have now studied regulation of BetP in vivo by independent variation of both the cytoplasmic K(+) concentration and the transmembrane osmotic gradient. The rise in internal K(+) was found to be necessary but not sufficient for BetP activation in cells. In addition hyperosmotic stress is required for full transport activity in cells, but not in proteoliposomes. This second stimulus of BetP could be mimicked in cells by the addition of the amphiphile tetracaine which hints to a relationship of this type of stimulus to a change in membrane properties. Determination of the molecular activity of BetP in both cells and proteoliposomes provided experimental evidence that in proteoliposomes BetP exists in a pre-stimulated condition and reaches full activity already in response to the K(+) stimulus. PMID:24384063

Maximov, Stanislav; Ott, Vera; Belkoura, Lhoussaine; Krämer, Reinhard

2014-05-01

248

Systematic in vivo RNAi analysis identifies IAPs as NEDD8-E3 ligases.  

PubMed

The intimate relationship between mediators of the ubiquitin (Ub)-signaling system and human diseases has sparked profound interest in how Ub influences cell death and survival. While the consequence of Ub attachment is intensely studied, little is known with regards to the effects of other Ub-like proteins (UBLs), and deconjugating enzymes that remove the Ub or UBL adduct. Systematic in vivo RNAi analysis identified three NEDD8-specific isopeptidases that, when knocked down, suppress apoptosis. Consistent with the notion that attachment of NEDD8 prevents cell death, genetic ablation of deneddylase 1 (DEN1) suppresses apoptosis. Unexpectedly, we find that Drosophila and human inhibitor of apoptosis (IAP) proteins can function as E3 ligases of the NEDD8 conjugation pathway, targeting effector caspases for neddylation and inactivation. Finally, we demonstrate that DEN1 reverses this effect by removing the NEDD8 modification. Altogether, our findings indicate that IAPs not only modulate cellular processes via ubiquitylation but also through attachment of NEDD8, thereby extending the complexity of IAP-mediated signaling. PMID:21145488

Broemer, Meike; Tenev, Tencho; Rigbolt, Kristoffer T G; Hempel, Sophie; Blagoev, Blagoy; Silke, John; Ditzel, Mark; Meier, Pascal

2010-12-10

249

Development of Spectral Domain Optical Coherence Tomography for in vivo Functional Imaging of Biological Tissues  

NASA Astrophysics Data System (ADS)

Optical coherence tomography is a rapidly developing optical imaging modality capable of noninvasively providing depth resolved information of biological tissue at micrometer scale. In this thesis, we described several OCT technologies that can be used to double the imaging depth, realize functional vasculature imaging of biological tissue and increase the imaging speed of OCT system. Aim 1: Use of a scanner to introduce spatial frequency modulation to OCT spectral interferograms for in vivo full-range Fourier-domain optical coherence tomography. A novel method was developed that could easily introduce a modulation frequency onto the X-direction (i.e., B-scan) of the FDOCT scanning system, enabling full-range Fourier-domain Optical Coherence Tomography (frFDOCT). Compared to the conventional FDOCT system, the newly developed frFDOCT system can provide increased system sensitivity and deeper imaging depth. The previous technology that can achieve frFDOCT either needed multiple steps for data capturing, which is time consuming, or required additional components which increased the system's complexity. The newly developed method generates a modulation spatial frequency in the spectral interferogram by simply offsetting the probe beam at the X-scanner. Aim 2: Using optical micro-angiography to achieve in vivo volumetric imaging of vascular perfusion within human retina and choroids. Optical Micro-Angiography (OMAG) is a functional extension of FDOCT technology. It can achieve visualization of vasculature network of biological tissue. In order to apply the OMAG method to image vasculature map of human retina and choroid, a phase compensation algorithm was developed, which could minimize the motion artifacts generated by the movements of human eye and head. Aim 3: Developing ultrahigh sensitive optical micro-angiography to achieve micro vasculature imaging of biological tissue. To improve the vasculature image quality, we developed ultrahigh sensitive OMAG (UHS-OMAG). Unlike conventional OMAG, UHS-OMAG applied the OMAG algorithm onto the slow direction of FDOCT scan (Y-direction). Because the time interval between adjacent B-frames is much longer than that between adjacent A-lines, UHS-OMAG can achieve much higher flow sensitivity compared to the conventional OMAG. In addition, the UHS-OMAG usually employed high frame rate (typically 300 frames per second) to achieve 3D scan, it cost much less time to finish one 3D scan compared to the traditional OMAG. However, when it was applied to visualize vasculature map of human tissue, the motion artifacts caused by the inevitable movements is still the biggest challenge. Based on the phase difference calculated from two adjacent B-frames, a new phase compensation algorithm was developed. Aim 4: Developing ultrahigh speed Spectral Domain OCT system through sequentially controlling two high speed line scan CMOS cameras. Two identical high speed line cameras were employed to build two home build high speed spectrometers. Through sequentially controlling the reading time period of two cameras, the imaging speed of the whole system could reach twice higher than the single camera system. The newly built 800 nm SDOCT system which can work at 500, 000 Hz A-lines capturing speed was then used to achieve in vivo 3D imaging in both high speed and large field of view mode. In addition, through combining with the OMAG algorithm, the newly developed system is capable of providing detailed micro-vasculature imaging of human retina and optic nerve head. (Abstract shortened by UMI.)

An, Lin

250

Function of dopamine transporter is compromised in DYT1 transgenic animal model in vivo  

PubMed Central

Early onset torsion dystonia (DYT1), the most common form of hereditary primary dystonia, is caused by a mutation in the TOR1A gene, which codes for the protein, torsinA. We previously examined the effect of the human mutant torsinA on striatal dopaminergic function in a conventional transgenic mouse model of DYT1 dystonia (hMT1), in which human mutant torsinA is expressed under the cytomegalovirus promotor. Systemic administration of amphetamine did not increase dopamine (DA) release as efficiently in these mice as compared with wild-type transgenic and non-transgenic mice. We, now, studied the contribution of the DA transporter (DAT) to amphetamine-induced DA release in hMT1 transgenic mice using in vivo no-net flux microdialysis. This method applies different concentrations of DA through the microdialysis probe and measures DA concentration at the output of the probe following an equilibrium period. The slope (extraction fraction) is the measure of the DAT activity in vivo. The slope for hMT1 transgenic mice was 0.58 ± 0.07 and for non-transgenic animals, 0.87 ± 0.06 (p < 0.05). We further investigated the efficacy of nomifensine (a specific DAT inhibitor) in inhibiting amphetamine-induced DA release. Local application of nomifensine 80 min before the systemic application of amphetamine inhibited DA release in both transgenic mice and their non-transgenic littermates. The efficiency of the inhibition appeared to be different, with mean values of 48% for hMT1 transgenic mice versus 84% for non-transgenic littermates. Moreover, we have evaluated basal and amphetamine-induced locomotion in hMT1 transgenic mice compared with their non-transgenic littermates, using an O-maze behavioral chamber. Basal levels of locomotion in the hMT1 transgenic mice showed that they moved much less than their non-transgenic littermates (0.9 ± 0.3 m for transgenic mice vs. 2.4 ± 0.7 m for non-transgenic littermates, p < 0.05). This relative reduction in locomotion was also observed following amphetamine administration (48.5 ± 6.7 m for transgenics vs. 73.7 ± 9.8 m for non-transgenics, p < 0.05). These results support the finding that there are altered dynamics of DA release and reuptake in hMT1 transgenic mice in vivo, with DAT activity is reduced in the presence of mutant torsinA, which is consistent with behavioral consequences such as reduced locomotion and (previously described) abnormal motor phenotypes such as increased hind-base width and impaired performance on the raised-beam task. These data implies that altered DAT function may contribute to impaired DA neurotransmission and clinical symptoms in human DYT1 dystonia.

Hewett, Jeff; Johansen, Peter; Sharma, Nutan; Standaert, David; Balcioglu, Aygul

2011-01-01

251

Quantitation of satellite cell proliferation in vivo using image analysis.  

PubMed

A nonisotopic, double fluorescence technique was developed to study myogenic satellite cell proliferation in posthatch turkey skeletal muscle. Labeled satellite cell nuclei were identified on enzymatically isolated myofiber segments using a mouse monoclonal antibody (anti-BrdU) followed by fluorescein-5-isothiocyanate (FITC) conjugated goat anti-mouse IgG secondary antibody. Myofiber nuclei (myonuclei+satellite cell nuclei) were counterstained with propidium iodide (PI). The myofiber segment length, myofiber segment diameter, and the number of PI and FITC labeled nuclei contained in each segment was determined using a Nikon fluorescence microscope, a SIT video camera and Image-1 software. Data collected by three different operators of the image analysis system revealed 5.0 +/- 1.4 satellite cell nuclei per 1000 myofiber nuclei and 5284 +/- 462 microns3 of cytoplasm surrounding each myofiber nucleus in the pectoralis thoracicus of 9-week-old tom turkeys. BrdU immunohistochemistry coupled with the new approach of PI staining of whole myofiber mounts is an effective combination to allow the use of an efficient semi-automated image analysis protocol. PMID:7819418

Mozdziak, P E; Fassel, T; Gregory, R; Schultz, E; Greaser, M L; Cassens, R G

1994-09-01

252

Enhanced in vivo targeting of murine nonparenchymal liver cells with monophosphoryl lipid a functionalized microcapsules.  

PubMed

A broad spectrum of infectious liver diseases emphasizes the need of microparticles for targeted delivery of immunomodulatory substances to the liver. Microcapsules (MCs) are particularly attractive for innovative drug and vaccine formulations, enabling the combination of antigen, drugs, and adjuvants. The present study aimed to develop microcapsules characterized by an enhanced liver deposition and accelerated uptake by nonparenchymal liver cells (NPCs). Initially, two formulations of biodegradable microcapsules were synthesized from either hydroxyethyl starch (HES) or mannose. Notably, HES-MCs accumulated primarily in the liver, while mannose particles displayed a lung preference. Functionalization of HES-MCs with anti-CD40, anti-DEC205, and/or monophosphoryl lipid A (MPLA) enhanced uptake of MCs by nonparenchymal liver cells in vitro. In contrast, only MPLA-coated HES-MCs promoted significantly the in vivo uptake by NPCs. Finally, HES-MCs equipped with MPLA, anti-CD40, and anti-DEC205 induced the secretion of TNF-?, IL-6 by Kupffer cells (KCs), and IFN-? and IL-12p70 by liver dendritic cells (DCs). The enhanced uptake and activation of KCs by MPLA-HES-MCs is a promising approach to prevent or treat infection, since KCs are exploited as an entry gate in various infectious diseases, such as malaria. In parallel, loading and activating liver DCs, usually prone to tolerance, bears the potential to induce antigen specific, intrahepatic immune responses necessary to prevent and treat infections affecting the liver. PMID:24901387

Pietrzak-Nguyen, Anette; Fichter, Michael; Dedters, Marvin; Pretsch, Leah; Gregory, Stephen H; Meyer, Claudius; Doganci, Aysefa; Diken, Mustafa; Landfester, Katharina; Baier, Grit; Gehring, Stephan

2014-07-14

253

Glycan variants of a respiratory syncytial virus antibody with enhanced effector function and in vivo efficacy  

PubMed Central

Respiratory syncytial virus (RSV) can cause devastating lower respiratory tract infections in preterm infants or when other serious health problems are present. Immunoprophylaxis with palivizumab (Synagis), a humanized IgG1 mAb, is the current standard of care for preventing RSV infection in at-risk neonates. We have explored the contribution of effector function to palivizumab efficacy using a plant-based expression system to produce palivizumab N-glycan structure variants with high homogeneity on different antibody isotypes. We compared these isotype and N-glycoform variants with commercially available palivizumab with respect to both in vitro receptor and C1q binding and in vivo efficacy. Whereas the affinity for antigen and neutralization activity of each variant were indistinguishable from those of palivizumab, their Fc? receptor binding profiles were very different, which was reflected in either a reduced or enhanced ability to influence the RSV lung titer in challenged cotton rats. Enhanced Fc? receptor binding was associated with reduced viral lung titers compared with palivizumab, whereas abrogation of receptor binding led to a drastic reduction in efficacy. The results support the hypotheses that classic antibody neutralization is a minor component of efficacy by palivizumab in the cotton rat and that antibody-dependent cell-mediated cytotoxicity activity can significantly enhance the efficacy of this antiviral mAb.

Hiatt, Andrew; Bohorova, Natasha; Bohorov, Ognian; Goodman, Charles; Kim, Do; Pauly, Michael H.; Velasco, Jesus; Whaley, Kevin J.; Piedra, Pedro A.; Gilbert, Brian E.; Zeitlin, Larry

2014-01-01

254

Glycan variants of a respiratory syncytial virus antibody with enhanced effector function and in vivo efficacy.  

PubMed

Respiratory syncytial virus (RSV) can cause devastating lower respiratory tract infections in preterm infants or when other serious health problems are present. Immunoprophylaxis with palivizumab (Synagis), a humanized IgG1 mAb, is the current standard of care for preventing RSV infection in at-risk neonates. We have explored the contribution of effector function to palivizumab efficacy using a plant-based expression system to produce palivizumab N-glycan structure variants with high homogeneity on different antibody isotypes. We compared these isotype and N-glycoform variants with commercially available palivizumab with respect to both in vitro receptor and C1q binding and in vivo efficacy. Whereas the affinity for antigen and neutralization activity of each variant were indistinguishable from those of palivizumab, their Fc? receptor binding profiles were very different, which was reflected in either a reduced or enhanced ability to influence the RSV lung titer in challenged cotton rats. Enhanced Fc? receptor binding was associated with reduced viral lung titers compared with palivizumab, whereas abrogation of receptor binding led to a drastic reduction in efficacy. The results support the hypotheses that classic antibody neutralization is a minor component of efficacy by palivizumab in the cotton rat and that antibody-dependent cell-mediated cytotoxicity activity can significantly enhance the efficacy of this antiviral mAb. PMID:24711420

Hiatt, Andrew; Bohorova, Natasha; Bohorov, Ognian; Goodman, Charles; Kim, Do; Pauly, Michael H; Velasco, Jesus; Whaley, Kevin J; Piedra, Pedro A; Gilbert, Brian E; Zeitlin, Larry

2014-04-22

255

Localization of recombination proteins and Srs2 reveals anti-recombinase function in vivo.  

PubMed

Homologous recombination (HR), although an important DNA repair mechanism, is dangerous to the cell if improperly regulated. The Srs2 "anti-recombinase" restricts HR by disassembling the Rad51 nucleoprotein filament, an intermediate preceding the exchange of homologous DNA strands. Here, we cytologically characterize Srs2 function in vivo and describe a novel mechanism for regulating the initiation of HR. We find that Srs2 is recruited separately to replication and repair centers and identify the genetic requirements for recruitment. In the absence of Srs2 activity, Rad51 foci accumulate, and surprisingly, can form in the absence of Rad52 mediation. However, these Rad51 foci do not represent repair-proficient filaments, as determined by recombination assays. Antagonistic roles for Rad52 and Srs2 in Rad51 filament formation are also observed in vitro. Furthermore, we provide evidence that Srs2 removes Rad51 indiscriminately from DNA, while the Rad52 protein coordinates appropriate filament reformation. This constant breakdown and rebuilding of filaments may act as a stringent quality control mechanism during HR. PMID:19506039

Burgess, Rebecca C; Lisby, Michael; Altmannova, Veronika; Krejci, Lumir; Sung, Patrick; Rothstein, Rodney

2009-06-15

256

Phenotypic and in vivo functional characterization of immortalized human fetal liver cells  

PubMed Central

We report the establishment and characterization of immortalized human fetal liver progenitor cells by expression of the Simian virus 40 large T (SV40 LT) antigen. Well-characterized cells at various passages were transplanted into nude mice with acute liver injury and tested for functional capacity. The SV40LT antigen-immortalized fetal liver cells showed a morphology similar to primary cells. Cultured cells demonstrated stable phenotypic expression in various passages, of hepatic markers such as albumin, CK 8, CK18, transcription factors HNF-4? and HNF-1? and CYP3A/7. The cells did not stain for any of the tested cancer-associated markers. Albumin, HNF-4? and CYP3A7 expression was confirmed by reverse transcription polymerase chain reaction (RT-PCR). Flow cytometry showed expression of some progenitor cell markers. In vivo study showed that the cells expressed both fetal and differentiated hepatocytes markers. Our study suggests new approaches to expand hepatic progenitor cells, analyze their fate in animal models aiming at cell therapy of hepatic diseases.

Patil, Pradeep B.; Begum, Setara; Joshi, Meghnad; Kleman, Marika I; Olausson, Michael

2014-01-01

257

Functionalization of iron oxide magnetic nanoparticles with targeting ligands: their physicochemical properties and in vivo behavior  

PubMed Central

Aims To develop and evaluate two tumor-specific nanoprobes by functionalization of a PEG-immobilized nanoparticle with arginine-glycine-aspartic acid (RGD) or chlorotoxin (CTX) ligand that targets ?v?3 integrin and MMP-2 receptors, respectively. Materials and Methods The nanoprobes were made of iron oxide cores, biocompatible polymer coating, and surface-conjugated RGD or CTX peptide. The tumor-targeting specificity of the nanoprobes was evaluated both in vitro and in vivo. Results and Discussion Both nanoprobes were highly dispersive and exhibited excellent long-term stability in cell culture media. The RGD-conjugated nanoprobe displayed a strong initial accumulation near neovasculatures in tumors followed by quick clearance. Conversely, the CTX-enabled nanoprobe exhibited sustained accumulation throughout the tumor. Conclusion These findings revealed the influence of the targeting ligands on the intratumoral distribution of the ligand-enabled nanoprobes. With flexible surface chemistry, our nanoparticle platform can be used in a modular fashion to conjugate biomolecules for intended applications.

Fang, Chen; Veiseh, Omid; Kievit, Forrest; Bhattarai, Narayan; Wang, Freddy; Stephen, Zach; Li, Chun; Lee, Donghoon; Ellenbogen, Richard G.; Zhang, Miqin

2010-01-01

258

Differential regulation of human and murine P-selectin expression and function in vivo.  

PubMed

Leukocytes roll on P-selectin after its mobilization from secretory granules to the surfaces of platelets and endothelial cells. Tumor necrosis factor (TNF), IL-1?, and lipopolysaccharide increase synthesis of P-selectin in murine but not in human endothelial cells. To explore the physiological significance of this difference in gene regulation, we made transgenic mice bearing the human Selp gene and crossed them with mice lacking murine P-selectin (Selp(-/-)). The transgenic mice constitutively expressed human P-selectin in platelets, endothelial cells, and macrophages. P-selectin mediated comparable neutrophil migration into the inflamed peritoneum of transgenic and wild-type (WT) mice. Leukocytes rolled similarly on human or murine P-selectin on activated murine platelets and in venules of the cremaster muscle subjected to trauma. However, TNF increased murine P-selectin in venules, slowing rolling and increasing adhesion, whereas it decreased human P-selectin, accelerating rolling and decreasing adhesion. Both P- and E-selectin mediated basal rolling in the skin of WT mice, but E-selectin dominated rolling in transgenic mice. During contact hypersensitivity, murine P-selectin messenger (m) RNA was up-regulated and P-selectin was essential for leukocyte recruitment. However, human P-selectin mRNA was down-regulated and P-selectin contributed much less to leukocyte recruitment. These findings reveal functionally significant differences in basal and inducible expression of human and murine P-selectin in vivo. PMID:21149548

Liu, Zhenghui; Miner, Jonathan J; Yago, Tadayuki; Yao, Longbiao; Lupu, Florea; Xia, Lijun; McEver, Rodger P

2010-12-20

259

Differential regulation of human and murine P-selectin expression and function in vivo  

PubMed Central

Leukocytes roll on P-selectin after its mobilization from secretory granules to the surfaces of platelets and endothelial cells. Tumor necrosis factor (TNF), IL-1?, and lipopolysaccharide increase synthesis of P-selectin in murine but not in human endothelial cells. To explore the physiological significance of this difference in gene regulation, we made transgenic mice bearing the human Selp gene and crossed them with mice lacking murine P-selectin (Selp?/?). The transgenic mice constitutively expressed human P-selectin in platelets, endothelial cells, and macrophages. P-selectin mediated comparable neutrophil migration into the inflamed peritoneum of transgenic and wild-type (WT) mice. Leukocytes rolled similarly on human or murine P-selectin on activated murine platelets and in venules of the cremaster muscle subjected to trauma. However, TNF increased murine P-selectin in venules, slowing rolling and increasing adhesion, whereas it decreased human P-selectin, accelerating rolling and decreasing adhesion. Both P- and E-selectin mediated basal rolling in the skin of WT mice, but E-selectin dominated rolling in transgenic mice. During contact hypersensitivity, murine P-selectin messenger (m) RNA was up-regulated and P-selectin was essential for leukocyte recruitment. However, human P-selectin mRNA was down-regulated and P-selectin contributed much less to leukocyte recruitment. These findings reveal functionally significant differences in basal and inducible expression of human and murine P-selectin in vivo.

Liu, Zhenghui; Miner, Jonathan J.; Yago, Tadayuki; Yao, Longbiao; Lupu, Florea; Xia, Lijun

2010-01-01

260

[In vivo studies of the main functional systems in the heteronemertean pilidium larva].  

PubMed

There is performed in vivo morphological study of the White Sea heteronemerteans belonging to the type of pilidium pyramidale (conussoidale). Based on the layer-by-layer microshooting with subsequent computer processing, development of the pilidium digestive, nervous, and muscle systems is described from the stage following at once the gastrula to the premetamorphose larva. Peculiarities of structural organization of the main functional systems are revealed depending on the larva size and the stage of formation of imaginal discs. It is first shown that even in the not completely formed pilidium, neurons are located not only in integuments and wall of the digestive tract, but also in the depth of cupola along the central muscle retractor. Their processes are distributed between the main body parts and organs by seeming to perform connections of the apical organ and central muscle retractor with the digestive tract, blades, and the nerve plexus of the cupola wall. In the digestive tract between pharynx and stomach in the formed pilidium, the sphincter is first revealed. It has been shown that in the course of larva development, the non-orderly arranged and poorly developed muscle fibers gradually form in the blade the fan-like, whereas in the cupola wall, the net-like structure. PMID:20799611

Za?tseva, O V; Fliachinskaia, L P

2010-01-01

261

Localization of recombination proteins and Srs2 reveals anti-recombinase function in vivo  

PubMed Central

Homologous recombination (HR), although an important DNA repair mechanism, is dangerous to the cell if improperly regulated. The Srs2 “anti-recombinase” restricts HR by disassembling the Rad51 nucleoprotein filament, an intermediate preceding the exchange of homologous DNA strands. Here, we cytologically characterize Srs2 function in vivo and describe a novel mechanism for regulating the initiation of HR. We find that Srs2 is recruited separately to replication and repair centers and identify the genetic requirements for recruitment. In the absence of Srs2 activity, Rad51 foci accumulate, and surprisingly, can form in the absence of Rad52 mediation. However, these Rad51 foci do not represent repair-proficient filaments, as determined by recombination assays. Antagonistic roles for Rad52 and Srs2 in Rad51 filament formation are also observed in vitro. Furthermore, we provide evidence that Srs2 removes Rad51 indiscriminately from DNA, while the Rad52 protein coordinates appropriate filament reformation. This constant breakdown and rebuilding of filaments may act as a stringent quality control mechanism during HR.

Burgess, Rebecca C.; Lisby, Michael; Altmannova, Veronika; Krejci, Lumir; Sung, Patrick

2009-01-01

262

Rank estimation and the multivariate analysis of in vivo fast-scan cyclic voltammetric data  

PubMed Central

Principal component regression has been used in the past to separate current contributions from different neuromodulators measured with in vivo fast-scan cyclic voltammetry. Traditionally, a percent cumulative variance approach has been used to determine the rank of the training set voltammetric matrix during model development, however this approach suffers from several disadvantages including the use of arbitrary percentages and the requirement of extreme precision of training sets. Here we propose that Malinowski’s F-test, a method based on a statistical analysis of the variance contained within the training set, can be used to improve factor selection for the analysis of in vivo fast-scan cyclic voltammetric data. These two methods of rank estimation were compared at all steps in the calibration protocol including the number of principal components retained, overall noise levels, model validation as determined using a residual analysis procedure, and predicted concentration information. By analyzing 119 training sets from two different laboratories amassed over several years, we were able to gain insight into the heterogeneity of in vivo fast-scan cyclic voltammetric data and study how differences in factor selection propagate throughout the entire principal component regression analysis procedure. Visualizing cyclic voltammetric representations of the data contained in the retained and discarded principal components showed that using Malinowski’s F-test for rank estimation of in vivo training sets allowed for noise to be more accurately removed. Malinowski’s F-test also improved the robustness of our criterion for judging multivariate model validity, even though signal-to-noise ratios of the data varied. In addition, pH change was the majority noise carrier of in vivo training sets while dopamine prediction was more sensitive to noise.

Keithley, Richard B.; Carelli, Regina M.; Wightman, R. Mark

2010-01-01

263

In Vivo Fluorometric Assessment of Cyclosporine on Mitochondrial Function During Myocardial Ischemia and Reperfusion  

PubMed Central

Background Cyclosporine A (CsA) limits myocardial reperfusion injury and preserves mitochondrial integrity, but its influence on mitochondrial function has not been described in vivo. Auto-fluorescence of mitochondrial nicotinamide adenine dinucleotide and flavin adenine dinucleotide correlate with mitochondrial dysfunction. We hypothesized that CsA limits mitochondrial dysfunction and that fluorometry can quantify this influence. Methods Seventeen rabbits were studied: untreated (UnT, n = 7), CsA preinfarction (CsAp, n = 6), and CsA on reperfusion (CsAr, n = 4). Animals underwent 30 minutes of myocardial ischemia and 3 hours reperfusion. Infarct size was determined by staining. Nicotinamide adenine dinucleotide and flavin adenine dinucleotide fluorescence was continually measured in the risk area. The redox ratio was calculated [flavin adenine dinucleotidef/(flavin adenine dinucleotidef + nicotinamide adenine dinucleotidef)]. Electron microscopy evaluated mitochondria morphology. Results The infarct size by group was 39.1% ± 1.7% in CsAp, 39.1% ± 1.7% in CsAr, and 53.4% ± 1.9% in UnT (p < 0.001). During ischemia, the CsAp group demonstrated less hypoxic reduction, with the redox ratio decreasing to 75.6% ± 4.1% of baseline. The UnT and CsAr groups deceased to 67.1% ± 4.0% and 67.2% ± 3.6%, respectively (p < 0.005). During reperfusion the UnT group redox ratio increased to 1.59 ± 0.04 times baseline. This increase was blunted in the CsAp (1.17 ± 0.04, p = 0.026) and CsAr (1.35 ± 0.02, p = 0.056) groups. Electron microscopy revealed reduced mitochondrial disruption in CsAp (19.7% ± 7.6%) and CsAr (18.1% ± 7.1%) rabbits compared with UnT (53.3% ± 12.5%). Conclusions Fluorometric spectroscopy can be used in vivo to quantitatively assess the time course of CsA’s influence on the mitochondrial dysfunction associated with myocardial ischemia and reperfusion.

Matsubara, Muneaki; Ranji, Mahsa; Leshnower, Bradley G.; Noma, Mio; Ratcliffe, Sarah J.; Chance, Britton; Gorman, Robert C.; Gorman, Joseph H.

2011-01-01

264

An Ex Vivo Model in Human Femoral Heads for Histopathological Study and Resonance Frequency Analysis of Dental Implant Primary Stability  

PubMed Central

Objective. This study was designed to explore relationships of resonance frequency analysis (RFA)—assessed implant stability (ISQ values) with bone morphometric parameters and bone quality in an ex vivo model of dental implants placed in human femoral heads and to evaluate the usefulness of this model for dental implant studies. Material and Methods. This ex vivo study included femoral heads from 17 patients undergoing surgery for femoral neck fracture due to osteoporosis (OP) (n = 7) or for total prosthesis joint replacement due to severe hip osteoarthrosis (OA) (n = 10). Sixty 4.5 × 13?mm Dentsply Astra implants were placed, followed by RFA. CD44 immunohistochemical analysis for osteocytes was also carried out. Results. As expected, the analysis yielded significant effects of femoral head type (OA versus OA) (P < 0.001), but not of the implants (P = 0.455) or of the interaction of the two factors (P = 0.848). Bonferroni post hoc comparisons showed a lower mean ISQ for implants in decalcified (50.33 ± 2.92) heads than in fresh (66.93 ± 1.10) or fixated (70.77 ± 1.32) heads (both P < 0.001). The ISQ score (fresh) was significantly higher for those in OA (73.52 ± 1.92) versus OP (67.13 ± 1.09) heads. However, mixed linear analysis showed no significant association between ISQ scores and morphologic or histomorphometric results (P > 0.5 in all cases), and no significant differences in ISQ values were found as a function of the length or area of the cortical layer (both P > 0.08). Conclusion. Although RFA-determined ISQ values are not correlated with morphometric parameters, they can discriminate bone quality (OP versus OA). This ex vivo model is useful for dental implant studies.

Hernandez-Cortes, Pedro; Galindo-Moreno, Pablo; Catena, Andres; Ortega-Oller, Inmaculada; Salas-Perez, Jose; Gomez-Sanchez, Rafael; Aguilar, Mariano; Aguilar, David

2014-01-01

265

In vivo coassembly of a divergent beta-tubulin subunit (c beta 6) into microtubules of different function  

PubMed Central

alpha- and beta-Tubulin are encoded in vertebrate genomes by a family of approximately 6-7 functional genes whose polypeptide products differ in amino acid sequence. In the chicken, one beta-tubulin isotype (c beta 6) has previously been found to be expressed only in thrombocytes and erythroid cells, where it is assembled into a circumferential ring of marginal band microtubules. In light of its unique in vivo utilization and its divergent assembly properties in vitro, we used DNA transfection to test whether this isotype could be assembled in vivo into microtubules of divergent functions. Using an antibody specific to c beta 6, we have found that upon transfection this polypeptide is freely coassembled into an extensive array of interphase cytoplasmic microtubules and into astral and pole-to-chromosome or pole-to-pole microtubules during mitosis. Further, examination of developing chicken erythrocytes reveals that both beta-tubulins that are expressed in these cells (c beta 6 and c beta 3) are found as co-polymers of the two isoforms. These results, in conjunction with efforts that have localized various other beta-tubulin isotypes, demonstrate that to the resolution limit afforded by light microscopy in vivo microtubules in vertebrates are random copolymers of available isotypes. Although these findings are consistent with functional interchangeability of beta- tubulin isotypes, we have also found that in vivo microtubules enriched in c beta 3 polypeptides are more sensitive to cold depolymerization than those enriched in c beta 6. This differential quantitative utilization of the two endogenous isotypes documents that some in vivo functional differences between isotypes do exist.

1987-01-01

266

An analytical model for elucidating tendon tissue structure and biomechanical function from in vivo cellular confocal microscopy images.  

PubMed

Fibered confocal laser scanning microscopes have given us the ability to image fluorescently labeled biological structures in vivo and at exceptionally high spatial resolutions. By coupling this powerful imaging modality with classic optical elastography methods, we have developed novel techniques that allow us to assess functional mechanical integrity of soft biological tissues by measuring the movements of cells in response to externally applied mechanical loads. Using these methods we can identify minute structural defects, monitor the progression of certain skeletal tissue disease states, and track subsequent healing following therapeutic intervention in the living animal. Development of these methods using a murine Achilles tendon model has revealed that the hierarchical and composite anatomical structure of the tendon presents various technical challenges that can confound a mechanical analysis of local material properties. Specifically, interfascicle gliding can yield complex cellular motions that must be interpreted within the context of an appropriate anatomical model. In this study, we explore the various classes of cellular images that may result from fibered confocal microscopy of the murine Achilles tendon, and introduce a simple two-fascicle model to interpret the images in terms of mechanical strains within the fascicles, as well as the relative gliding between fascicles. PMID:19122452

Snedeker, J G; Pelled, G; Zilberman, Y; Ben Arav, A; Huber, E; Müller, R; Gazit, D

2009-01-01

267

Isolation and functional characterization of human erythroblasts at distinct stages: implications for understanding of normal and disordered erythropoiesis in vivo.  

PubMed

Terminal erythroid differentiation starts from morphologically recognizable proerythroblasts that proliferate and differentiate to generate red cells. Although this process has been extensively studied in mice, its characterization in humans is limited. By examining the dynamic changes of expression of membrane proteins during in vitro human terminal erythroid differentiation, we identified band 3 and ?4 integrin as optimal surface markers for isolating 5 morphologically distinct populations at successive developmental stages. Functional analysis revealed that these purified cell populations have distinct mitotic capacity. Use of band 3 and ?4 integrin enabled us to isolate erythroblasts at specific developmental stages from primary human bone marrow. The ratio of erythroblasts at successive stages followed the predicted 1:2:4:8:16 pattern. In contrast, bone marrows from myelodysplastic syndrome patients exhibited altered terminal erythroid differentiation profiles. Thus, our findings not only provide new insights into the genesis of the red cell membrane during human terminal erythroid differentiation but also offer a means of isolating and quantifying each developmental stage during terminal erythropoiesis in vivo. Our findings should facilitate a comprehensive cellular and molecular characterization of each specific developmental stage of human erythroblasts and should provide a powerful means of identifying stage-specific defects in diseases associated with pathological erythropoiesis. PMID:23422750

Hu, Jingping; Liu, Jing; Xue, Fumin; Halverson, Gregory; Reid, Marion; Guo, Anqi; Chen, Lixiang; Raza, Azra; Galili, Naomi; Jaffray, Julie; Lane, Joseph; Chasis, Joel Anne; Taylor, Naomi; Mohandas, Narla; An, Xiuli

2013-04-18

268

Isolation and functional characterization of human erythroblasts at distinct stages: implications for understanding of normal and disordered erythropoiesis in vivo  

PubMed Central

Terminal erythroid differentiation starts from morphologically recognizable proerythroblasts that proliferate and differentiate to generate red cells. Although this process has been extensively studied in mice, its characterization in humans is limited. By examining the dynamic changes of expression of membrane proteins during in vitro human terminal erythroid differentiation, we identified band 3 and ?4 integrin as optimal surface markers for isolating 5 morphologically distinct populations at successive developmental stages. Functional analysis revealed that these purified cell populations have distinct mitotic capacity. Use of band 3 and ?4 integrin enabled us to isolate erythroblasts at specific developmental stages from primary human bone marrow. The ratio of erythroblasts at successive stages followed the predicted 1:2:4:8:16 pattern. In contrast, bone marrows from myelodysplastic syndrome patients exhibited altered terminal erythroid differentiation profiles. Thus, our findings not only provide new insights into the genesis of the red cell membrane during human terminal erythroid differentiation but also offer a means of isolating and quantifying each developmental stage during terminal erythropoiesis in vivo. Our findings should facilitate a comprehensive cellular and molecular characterization of each specific developmental stage of human erythroblasts and should provide a powerful means of identifying stage-specific defects in diseases associated with pathological erythropoiesis.

Hu, Jingping; Liu, Jing; Xue, Fumin; Halverson, Gregory; Reid, Marion; Guo, Anqi; Chen, Lixiang; Raza, Azra; Galili, Naomi; Jaffray, Julie; Lane, Joseph; Chasis, Joel Anne; Taylor, Naomi; Mohandas, Narla

2013-01-01

269

Microtubule depolymerization normalizes in vivo myocardial contractile function in dogs with pressure-overload left ventricular hypertrophy  

NASA Technical Reports Server (NTRS)

BACKGROUND: Because initially compensatory myocardial hypertrophy in response to pressure overloading may eventually decompensate to myocardial failure, mechanisms responsible for this transition have long been sought. One such mechanism established in vitro is densification of the cellular microtubule network, which imposes a viscous load that inhibits cardiocyte contraction. METHODS AND RESULTS: In the present study, we extended this in vitro finding to the in vivo level and tested the hypothesis that this cytoskeletal abnormality is important in the in vivo contractile dysfunction that occurs in experimental aortic stenosis in the adult dog. In 8 dogs in which gradual stenosis of the ascending aorta had caused severe left ventricular (LV) pressure overloading (gradient, 152+/-16 mm Hg) with contractile dysfunction, LV function was measured at baseline and 1 hour after the intravenous administration of colchicine. Cardiocytes obtained by biopsy before and after in vivo colchicine administration were examined in tandem. Microtubule depolymerization restored LV contractile function both in vivo and in vitro. CONCLUSIONS: These and additional corroborative data show that increased cardiocyte microtubule network density is an important mechanism for the ventricular contractile dysfunction that develops in large mammals with adult-onset pressure-overload-induced cardiac hypertrophy.

Koide, M.; Hamawaki, M.; Narishige, T.; Sato, H.; Nemoto, S.; DeFreyte, G.; Zile, M. R.; Cooper G, I. V.; Carabello, B. A.

2000-01-01

270

In vivo function of airway epithelial TLR2 in host defense against bacterial infection  

PubMed Central

Decreased Toll-like receptor 2 (TLR2) expression has been reported in patients with chronic obstructive pulmonary disease and in a murine asthma model, which may predispose the hosts to bacterial infections, leading to disease exacerbations. Since airway epithelial cells serve as the first line of respiratory mucosal defense, the present study aimed to reveal the role of airway epithelial TLR2 signaling to lung bacterial [i.e., Mycoplasma pneumoniae (Mp)] clearance. In vivo TLR2 gene transfer via intranasal inoculation of adenoviral vector was performed to reconstitute TLR2 expression in airway epithelium of TLR2?/? BALB/c mice, with or without ensuing Mp infection. TLR2 and lactotransferrin (LTF) expression in airway epithelial cells and lung Mp load were assessed. Adenovirus-mediated TLR2 gene transfer to airway epithelial cells of TLR2?/? mice reconstituted 30–40% TLR2 expression compared with TLR2+/+ cells. Such airway epithelial TLR2 reconstitution in TLR2?/? mice significantly reduced lung Mp load (an appropriate 45% reduction), coupled with elevated LTF expression. LTF expression in mice was shown to be mainly dependent on TLR2 signaling in response to Mp infection. Exogenous human LTF protein dose-dependently decreased lung bacterial load in Mp-infected TLR2?/? mice. In addition, human LTF protein directly dose-dependently decreased Mp levels in vitro. These data indicate that reconstitution of airway epithelial TLR2 signaling in TLR2?/? mice significantly restores lung defense against bacteria (e.g., Mp) via increased lung antimicrobial protein LTF production. Our findings may offer a deliverable approach to attenuate bacterial infections in airways of asthma or chronic obstructive pulmonary disease patients with impaired TLR2 function.

Wu, Qun; Jiang, Di; Minor, Maisha N.; Martin, Richard J.

2011-01-01

271

Inhibition of human platelet function in vitro and ex vivo by acetaminophen.  

PubMed

The effects of acetaminophen (APAP) in vitro, or ex vivo following APAP ingestion, on human platelet aggregation, 14C-5HT secretion, and thromboxane B2 (TxB2) formation were assessed. APAP added in vitro to citrated platelet-rich plasma (PRP) inhibited aggregation, secretion, and TxB2 formation induced by collagen, epinephrine, arachidonate, and the ionophore A23187, but had no effect on the responses induced by the endoperoxide analog U44069. Arachidonate-induced responses were inhibited by lower concentrations of APAP than were the responses to the other agonists. In PRP obtained 1 hour after ingestion of 650 mg or 1000 mg APAP, arachidonate-induced TxB2 formation was inhibited by 40-99% in five subjects tested, whereas inhibition of collagen- or epinephrine-induced TxB2 formation was less consistent. Aggregation and secretion responses were not altered by APAP ingestion in 4 of the 5 subjects, but were inhibited in the remaining subject, who had the highest plasma APAP levels. In contrast to aspirin and indomethacin, APAP-induced inhibition of collagen-stimulated TxB2 formation could be partially overcome with increasing collagen concentrations. No such partial correction occurred with epinephrine, however. In washed platelet suspensions labeled with 3H-arachidonate, both APAP and aspirin inhibited the formation of labeled PGD2 and PGE2, as well as TxB2. These results suggest that APAP acts in human platelets as a reversible inhibitor of cyclo-oxygenase, as found previously in other tissues, and that recent APAP ingestion can, on occasion, produce inhibition of platelet functional responses measured in vitro. PMID:2499947

Lages, B; Weiss, H J

1989-03-15

272

Impact of RNA editing on functions of the serotonin 2C receptor in vivo.  

PubMed

Transcripts encoding 5-HT(2C) receptors are modified posttranscriptionally by RNA editing, generating up to 24 protein isoforms. In recombinant cells, the fully edited isoform, 5-HT(2C-VGV), exhibits blunted G-protein coupling and reduced constitutive activity. The present studies examine the signal transduction properties of 5-HT(2C-VGV) receptors in brain to determine the in vivo consequences of altered editing. Using mice solely expressing the 5-HT(2C-VGV) receptor (VGV/Y), we demonstrate reduced G-protein coupling efficiency and high-affinity agonist binding of brain 5-HT(2C-VGV) receptors. However, enhanced behavioral sensitivity to a 5-HT(2C) receptor agonist was also seen in mice expressing 5-HT(2C-VGV) receptors, an unexpected finding given the blunted G-protein coupling. In addition, mice expressing 5-HT(2C-VGV) receptors had greater sensitivity to a 5-HT(2C) inverse agonist/antagonist enhancement of dopamine turnover relative to wild-type mice. These behavioral and biochemical results are most likely explained by increases in 5-HT(2C) receptor binding sites in the brains of mice solely expressing 5-HT(2C-VGV) receptors. We conclude that 5-HT(2C-VGV) receptor signaling in brain is blunted, but this deficiency is masked by a marked increase in 5-HT(2C) receptor binding site density in mice solely expressing the VGV isoform. These findings suggest that RNA editing may regulate the density of 5-HT(2C) receptor binding sites in brain. We further caution that the pattern of 5-HT(2C) receptor RNA isoforms may not reflect the pattern of protein isoforms, and hence the inferred overall function of the receptor. PMID:20582266

Olaghere da Silva, Uade B; Morabito, Michael V; Canal, Clinton E; Airey, David C; Emeson, Ronald B; Sanders-Bush, Elaine

2010-01-01

273

Impact of RNA Editing on Functions of the Serotonin 2C Receptor in vivo  

PubMed Central

Transcripts encoding 5-HT2C receptors are modified posttranscriptionally by RNA editing, generating up to 24 protein isoforms. In recombinant cells, the fully edited isoform, 5-HT2C-VGV, exhibits blunted G-protein coupling and reduced constitutive activity. The present studies examine the signal transduction properties of 5-HT2C-VGV receptors in brain to determine the in vivo consequences of altered editing. Using mice solely expressing the 5-HT2C-VGV receptor (VGV/Y), we demonstrate reduced G-protein coupling efficiency and high-affinity agonist binding of brain 5-HT2C-VGV receptors. However, enhanced behavioral sensitivity to a 5-HT2C receptor agonist was also seen in mice expressing 5-HT2C-VGV receptors, an unexpected finding given the blunted G-protein coupling. In addition, mice expressing 5-HT2C-VGV receptors had greater sensitivity to a 5-HT2C inverse agonist/antagonist enhancement of dopamine turnover relative to wild-type mice. These behavioral and biochemical results are most likely explained by increases in 5-HT2C receptor binding sites in the brains of mice solely expressing 5-HT2C-VGV receptors. We conclude that 5-HT2C-VGV receptor signaling in brain is blunted, but this deficiency is masked by a marked increase in 5-HT2C receptor binding site density in mice solely expressing the VGV isoform. These findings suggest that RNA editing may regulate the density of 5-HT2C receptor binding sites in brain. We further caution that the pattern of 5-HT2C receptor RNA isoforms may not reflect the pattern of protein isoforms, and hence the inferred overall function of the receptor.

Olaghere da Silva, Uade B.; Morabito, Michael V.; Canal, Clinton E.; Airey, David C.; Emeson, Ronald B.; Sanders-Bush, Elaine

2009-01-01

274

In vivo skin biophysical behaviour and surface topography as a function of ageing.  

PubMed

Normal skin ageing is characterised by an alteration of the underlying connective tissue with measurable consequences on global skin biophysical properties. The cutis laxa syndrome, a rare genetic disorder, is considered as an accelerated ageing process since patients appear prematurely aged due to alterations of dermal elastic fibres. In the present study, we compared the topography and the biomechanical parameters of normal aged skin with an 17 year old cutis laxa patient. Skin topography analyses were conducted on normal skin at different ages. The results indicate that the skin relief highly changes as a function of ageing. The cutaneous lines change from a relatively isotropic orientation to a highly anisotropic orientation. This reorganisation of the skin relief during the ageing process might be due to a modification of the skin mechanical properties, and particularly to a modification of the dermis mechanical properties. A specific bio-tribometer, based on the indentationtechnique under light load, has been developed to study the biophysical properties of the human skin in vivo through two main parameters: the physico-chemical properties of the skin surface, by measuring the maximum adhesion force between the skin and the bio-tribometer; and the bulk mechanical properties. Our results show that the pull-off force between the skin and the biotribometer as well as the skin Young's modulus decrease with age. In the case of the young cutis laxa patient, the results obtained were similar to those observed for aged individuals. These results are very interesting and encouraging since they would allow the monitoring of the cutis laxa skin in a standardised and non-invasive way to better characterize either the evolution of the disease or the benefit of a treatment. PMID:23664827

Pailler-Mattei, C; Debret, R; Vargiolu, R; Sommer, P; Zahouani, H

2013-12-01

275

Kynurenergic manipulations influence excitatory synaptic function and excitotoxic vulnerability in the rat hippocampus in vivo.  

PubMed

Competing enzymatic mechanisms degrade the tryptophan metabolite L-kynurenine to kynurenate, an inhibitory and neuroprotective compound, and to the neurotoxins 3-hydroxykynurenine and quinolinate. Kynurenine 3-hydroxylase inhibitors such as PNU 156561 shift metabolism towards enhanced kynurenate production, and this effect may underlie the recently discovered anticonvulsant and neuroprotective efficacy of these drugs. Using electrophysiological and neurotoxicological endpoints, we now used PNU 156561 as a tool to examine the functional interplay of kynurenate, 3-hydroxykynurenine and quinolinate in the rat hippocampus in vivo. First, population spike amplitude in area CA1 and the extent of quinolinate-induced excitotoxic neurodegeneration were studied in animals receiving acute or prolonged intravenous infusions of L-kynurenine, PNU 156561, (L-kynurenine+PNU 156561) or kynurenate. Only the latter two treatments, but not L-kynurenine or PNU 156561 alone, caused substantial inhibition of evoked responses in area CA1, and only prolonged (3h) infusion of (L-kynurenine+PNU 156561) or kynurenate was neuroprotective. Biochemical analyses in separate animals revealed that the levels of kynurenate attained in both blood and brain (hippocampus) were essentially identical in rats receiving extended infusions of L-kynurenine alone or (L-kynurenine+PNU 156561) (4 and 7microM, respectively, after an infusion of 90 or 180min). However, addition of the kynurenine 3-hydroxylase inhibitor resulted in a significant decrement in the formation of 3-hydroxykynurenine and quinolinate in both blood and brain. These data suggest that the ratio between kynurenate and 3-hydroxykynurenine and/or quinolinate in the brain is a critical determinant of neuronal excitability and viability. The anticonvulsant and neuroprotective potency of kynurenine 3-hydroxylase inhibitors may therefore be due to the drugs' dual action on both branches of the kynurenine pathway of tryptophan degradation. PMID:10799756

Wu, H Q; Guidetti, P; Goodman, J H; Varasi, M; Ceresoli-Borroni, G; Speciale, C; Scharfman, H E; Schwarcz, R

2000-01-01

276

In vivo imaging of zebrafish digestive organ function using multiple quenched fluorescent reporters  

PubMed Central

Optical clarity of larvae makes the zebrafish ideal for real-time analyses of vertebrate organ function through the use of fluorescent reporters of enzymatic activities. A key function of digestive organs is to couple the generation of enzymes with mechanical processes that enable nutrient availability and absorption. However, it has been extremely difficult, and in many cases not possible, to directly observe digestive processes in a live vertebrate. Here we describe a new method to visualize intestinal protein and lipid processing simultaneously in live zebrafish larvae using a quenched fluorescent protein (EnzChek) and phospholipid (PED6). By employing these reagents, we found that wild-type larvae exhibit significant variation in intestinal phospholipase and protease activities within a group but display a strong correlation between the activities within individuals. Furthermore, we found that pancreas function is essential for larval digestive protease activity but not for larval intestinal phospholipase activity. Although fat-free (ffr) mutant larvae were previously described to exhibit impaired lipid processes, we found they also had significantly reduced protease activity. Finally, we selected and evaluated compounds that were previously suggested to have altered phospholipase activity and are known or suspected to have inflammatory effects in the intestinal tract including nonsteroidal anti-inflammatory drugs, and identified a compound that significantly increases intestinal phospholipid processing. Thus the multiple fluorescent reporter-based methodology facilitates the rapid analysis of digestive organ function in live zebrafish larvae.

Hama, Kotaro; Provost, Elayne; Baranowski, Timothy C.; Rubinstein, Amy L.; Anderson, Jennifer L.; Leach, Steven D.; Farber, Steven A.

2009-01-01

277

In vivo stem cell function of interleukin-3-induced blast cells  

SciTech Connect

The treatment of mice with high doses of 5-fluorouracil (5-FU) results in an enrichment of primitive hematopoietic progenitors. Using this procedure, the authors obtained a new class of murine hematopoietic colonies that had very high secondary plating efficiencies in vitro and could differentiate into not only myeloid cells but also into lymphoid lineage cells. The phenotypes of interleukin-3 (IL-3) induced blast colony cells were Thy-1-positive and lineage-marker-negative. They examined whether these blast colony cells contained primitive hematopoietic stem cells in vivo and could reconstitute hematopoietic tissues in lethally irradiated mice. Blast colony cells could generate macroscopic visible spleen colonies on days 8 and 12, and 5 {times} 10(3) blast cells were sufficient to protect them from lethally irradiation. It was shown that 6 or 8 weeks after transplantation of 5 {times} 10(3) blast cells, donor male cells were detected in the spleen and thymus of the female recipients but not in the bone marrow by Southern blot analysis using Y-encoded DNA probe. After 10 weeks, bone marrow cells were partially repopulated from donor cells. In a congenic mouse system, donor-derived cells (Ly5.2) were detected in the thymus and spleen 6 weeks after transplantation. Fluorescence-activated cell sorter analyses showed that B cells and macrophages developed from donor cells in the spleen. In the thymus, donor-derived cells were found in CD4, CD8 double-positive, single-positive, and double-negative populations. Reconstitution of bone marrow was delayed and myeloid and lymphoid cells were detected 10 weeks after transplantation. These results indicate that IL-3-induced blast cells contain the primitive hematopoietic stem cells capable of reconstituting hematopoietic organs in lethally irradiated mice.

Tsunoda, J.; Okada, S.; Suda, J.; Nagayoshi, K.; Nakauchi, H.; Hatake, K.; Miura, Y.; Suda, T. (Department of Medicine, Jichi Medical School, Tochigi-ken (Japan))

1991-07-15

278

Quantitative analysis of gene function in the Drosophila embryo.  

PubMed Central

The specific functions of gene products frequently depend on the developmental context in which they are expressed. Thus, studies on gene function will benefit from systems that allow for manipulation of gene expression within model systems where the developmental context is well defined. Here we describe a system that allows for genetically controlled overexpression of any gene of interest under normal physiological conditions in the early Drosophila embryo. This regulated expression is achieved through the use of Drosophila lines that express a maternal mRNA for the yeast transcription factor GAL4. Embryos derived from females that express GAL4 maternally activate GAL4-dependent UAS transgenes at uniform levels throughout the embryo during the blastoderm stage of embryogenesis. The expression levels can be quantitatively manipulated through the use of lines that have different levels of maternal GAL4 activity. Specific phenotypes are produced by expression of a number of different developmental regulators with this system, including genes that normally do not function during Drosophila embryogenesis. Analysis of the response to overexpression of runt provides evidence that this pair-rule segmentation gene has a direct role in repressing transcription of the segment-polarity gene engrailed. The maternal GAL4 system will have applications both for the measurement of gene activity in reverse genetic experiments as well as for the identification of genetic factors that have quantitative effects on gene function in vivo.

Tracey, W D; Ning, X; Klingler, M; Kramer, S G; Gergen, J P

2000-01-01

279

Functional analysis of the SRV-1 RNA frameshifting pseudoknot.  

PubMed

Simian retrovirus type-1 uses programmed ribosomal frameshifting to control expression of the Gag-Pol polyprotein from overlapping gag and pol open-reading frames. The frameshifting signal consists of a heptanucleotide slippery sequence and a downstream-located 12-base pair pseudoknot. The solution structure of this pseudoknot, previously solved by NMR [Michiels,P.J., Versleijen,A.A., Verlaan,P.W., Pleij,C.W., Hilbers,C.W. and Heus,H.A. (2001) Solution structure of the pseudoknot of SRV-1 RNA, involved in ribosomal frameshifting. J. Mol. Biol., 310, 1109-1123] has a classical H-type fold and forms an extended triple helix by interactions between loop 2 and the minor groove of stem 1 involving base-base and base-sugar contacts. A mutational analysis was performed to test the functional importance of the triple helix for -1 frameshifting in vitro. Changing bases in L2 or base pairs in S1 involved in a base triple resulted in a 2- to 5-fold decrease in frameshifting efficiency. Alterations in the length of L2 had adverse effects on frameshifting. The in vitro effects were well reproduced in vivo, although the effect of enlarging L2 was more dramatic in vivo. The putative role of refolding kinetics of frameshifter pseudoknots is discussed. Overall, the data emphasize the role of the triple helix in -1 frameshifting. PMID:20639537

Olsthoorn, René C L; Reumerman, Richard; Hilbers, Cornelis W; Pleij, Cornelis W A; Heus, Hans A

2010-11-01

280

How mitochondrial dysfunction affects zebrafish development and cardiovascular function: an in vivo model for testing mitochondria-targeted drugs  

PubMed Central

Background and Purpose Mitochondria are a drug target in mitochondrial dysfunction diseases and in antiparasitic chemotherapy. While zebrafish is increasingly used as a biomedical model, its potential for mitochondrial research remains relatively unexplored. Here, we perform the first systematic analysis of how mitochondrial respiratory chain inhibitors affect zebrafish development and cardiovascular function, and assess multiple quinones, including ubiquinone mimetics idebenone and decylubiquinone, and the antimalarial atovaquone. Experimental Approach Zebrafish (Danio rerio) embryos were chronically and acutely exposed to mitochondrial inhibitors and quinone analogues. Concentration-response curves, developmental and cardiovascular phenotyping were performed together with sequence analysis of inhibitor-binding mitochondrial subunits in zebrafish versus mouse, human and parasites. Phenotype rescuing was assessed in co-exposure assays. Key Results Complex I and II inhibitors induced developmental abnormalities, but their submaximal toxicity was not additive, suggesting active alternative pathways for complex III feeding. Complex III inhibitors evoked a direct normal-to-dead transition. ATP synthase inhibition arrested gastrulation. Menadione induced hypochromic anaemia when transiently present following primitive erythropoiesis. Atovaquone was over 1000-fold less lethal in zebrafish than reported for Plasmodium falciparum, and its toxicity partly rescued by the ubiquinone precursor 4-hydroxybenzoate. Idebenone and decylubiquinone delayed rotenone- but not myxothiazol- or antimycin-evoked cardiac dysfunction. Conclusion and Implications This study characterizes pharmacologically induced mitochondrial dysfunction phenotypes in zebrafish, laying the foundation for comparison with future studies addressing mitochondrial dysfunction in this model organism. It has relevant implications for interpreting zebrafish disease models linked to complex I/II inhibition. Further, it evidences zebrafish's potential for in vivo efficacy or toxicity screening of ubiquinone analogues or antiparasitic mitochondria-targeted drugs.

Pinho, Brigida R; Santos, Miguel M; Fonseca-Silva, Anabela; Valentao, Patricia; Andrade, Paula B; Oliveira, Jorge M A

2013-01-01

281

Hydrothermal load flow using functional analysis  

Microsoft Academic Search

The hydrothermal scheduling problem is discussed. Optimal load flow solutions are obtained such that both maximum economy and reliability of the system are achieved. The scheduling problem is solved by use of functional analysis, and in this case the minimum norm formulation is employed. It is emphasized that the optimal solution found here is guaranteed to be the unique optimal

M. E. El-Hawary; G. S. Christensen

1973-01-01

282

Functional Analysis and Treatment of Severe Pica.  

ERIC Educational Resources Information Center

A two-phase functional analysis of a profoundly retarded 19-year-old male's pica behavior resulted in an effective staff-implemented treatment consisting of limited staff-client interaction and removal of a protective helmet which had previously been prescribed to help control pica. (Author/JW)

Mace, F. Charles; Knight, David

1986-01-01

283

In vivo activation analysis of organ cadmium using the Tsing Hua Mobile Educational Reactor  

Microsoft Academic Search

This work describes a nuclear facility forin vivo prompt gamma activation analysis (IVPGAA) using a moderated neutron beam from a 0.1 W Tsing-Hua Mobile Educational Reactor (THMER). The IVPGAA measurement is a new technique for toxic cadmium determination in organs, which can efficiently be used in clinical diagnosis. The low-power nuclear reactor provides a total neutron flux of 3.3·104 n·cm–2·s–1

Pao-Shu Chang; Chien Chung; Lig-Ji Yuan; Pao-Shan Weng

1985-01-01

284

Fucoidan Can Function as an Adjuvant In Vivo to Enhance Dendritic Cell Maturation and Function and Promote Antigen-Specific T Cell Immune Responses  

PubMed Central

Fucoidan, a sulfated polysaccharide purified from brown algae, has a variety of immune-modulation effects, including promoting antigen uptake and enhancing anti-viral and anti-tumor effects. However, the effect of fucoidan in vivo, especially its adjuvant effect on in vivo anti-tumor immune responses, was not fully investigated. In this study, we investigated the effect of fucoidan on the function of spleen dendritic cells (DCs) and its adjuvant effect in vivo. Systemic administration of fucoidan induced up-regulation of CD40, CD80 and CD86 expression and production of IL-6, IL-12 and TNF-? in spleen cDCs. Fucoidan also promoted the generation of IFN-?-producing Th1 and Tc1 cells in an IL-12-dependent manner. When used as an adjuvant in vivo with ovalbumin (OVA) antigen, fucoidan promoted OVA-specific antibody production and primed IFN-? production in OVA-specific T cells. Moreover, fucoidan enhanced OVA-induced up-regulation of MHC class I and II on spleen cDCs and strongly prompted the proliferation of OVA-specific CD4 and CD8 T cells. Finally, OVA immunization with fucoidan as adjuvant protected mice from the challenge with B16-OVA tumor cells. Taken together, these results suggest that fucoidan can function as an adjuvant to induce Th1 immune response and CTL activation, which may be useful in tumor vaccine development.

Jin, Jun-O; Zhang, Wei; Du, Jiang-Yuan; Wong, Ka-Wing; Oda, Tatsuya; Yu, Qing

2014-01-01

285

Genetic and molecular in vivo analysis of herpes simplex virus assembly in murine visual system neurons.  

PubMed

Herpes simplex virus (HSV) infects both epithelial cells and neuronal cells of the human host. Although HSV assembly has been studied extensively for cultured epithelial and neuronal cells, cultured neurons are biochemically, physiologically, and anatomically significantly different than mature neurons in vivo. Therefore, it is imperative that viral maturation and assembly be studied in vivo. To study viral assembly in vivo, we inoculated wild-type and replication-defective viruses into the posterior chamber of mouse eyes and followed infection in retinal ganglion cell bodies and axons. We used PCR techniques to detect viral DNA and RNA and electron microscopy immunohistochemistry and Western blotting to detect viral proteins in specific portions of the optic tract. This approach has shown that viral DNA replication is necessary for viral DNA movement into axons. Movement of viral DNA along ganglion cell axons occurs within capsid-like structures at the speed of fast axonal transport. These studies show that the combined use of intravitreal injections of replication-defective viruses and molecular probes allows the genetic analysis of essential viral replication and maturation processes in neurons in vivo. The studies also provide novel direct evidence for the axonal transport of viral DNA and support for the subassembly hypothesis of viral maturation in situ. PMID:16103165

LaVail, Jennifer H; Tauscher, Andrew N; Hicks, James W; Harrabi, Ons; Melroe, Gregory T; Knipe, David M

2005-09-01

286

In vivo versus simulation training: an interactional analysis of range and type of training exemplars.  

PubMed Central

We analyzed the role of the range of variation in training exemplars as a contextual variable influencing the effects of in vivo versus simulation training in producing generalized responding. Four mentally retarded adults received single case instruction, followed by general case instruction, on washing machine and dryer use; one task was taught using actual appliances (in vivo) and the other using simulation. In vivo and simulation training were counterbalanced across the two tasks for the 2 subject pairs, using a within-subjects Latin square design. With both paradigms, more errors were made after single case than after general case instruction during probe sessions with untrained washing machines and dryers. These results suggest that generalization errors were affected by the range of training exemplars and not by the use of simulated versus natural training stimuli. Although both general case simulation and general case in vivo training facilitated generalized performance of laundry skills, an analysis of training time and costs indicated that the former approach was more efficient. The study illustrates a methodology for studying complex interactions and guiding decisions on the optimal use of instructional alternatives.

Neef, N A; Lensbower, J; Hockersmith, I; DePalma, V; Gray, K

1990-01-01

287

Structure-Function Analysis of Yeast Tubulin  

PubMed Central

Microtubules play essential roles in a wide variety of cellular processes including cell division, motility, and vesicular transport. Microtubule function depends on the polymerization dynamics of tubulin, and specific interactions between tubulin and diverse microtubule-associated proteins. To date, investigation of the structural and functional properties of tubulin and tubulin mutants has been limited by the inability to obtain functional protein from overexpression systems, and by the heterogeneous mixture of tubulin isotypes typically isolated from higher eukaryotes. The budding yeast, Saccharomyces cerevisiae, has emerged as a leading system for tubulin structure-function analysis. Yeast cells encode a single beta-tubulin gene and can be engineered to express just one, of two, alpha isotypes. Moreover, yeast allows site-directed modification of tubulin genes at the endogenous loci expressed under the native promoter and regulatory elements. These advantageous features provide a homogeneous and controlled environment for analysis of the functional consequences of specific mutations. Here we present techniques to generate site-specific tubulin mutations in diploid and haploid cells, assess the ability of the mutated protein to support cell viability, measure overall microtubule stability, and define changes in the specific parameters of microtubule dynamic instability. We also outline strategies to determine whether mutations disrupt interactions with microtubule-associated proteins. Microtubule-based functions in yeast are well defined, which allows the observed changes in microtubule properties to be related to the role of microtubules in specific cellular processes.

Luchniak, Anna; Fukuda, Yusuke; Gupta, Mohan L.

2014-01-01

288

Calcium-transport function of the chick embryonic chorioallantoic membrane. I. In vivo and in vitro characterization.  

PubMed

During chick embryonic development, the chorioallantoic membrane (CAM) is responsible for the mobilization of shell calcium into the embryonic circulation. The calcium-transport function of the CAM was studied here by measuring CAM calcium uptake in vivo and in vitro. The in vivo technique involved the use of an uptake chamber constructed on top of the CAM in situ. The in vitro methods included two systems: CAM tissue disks and cell-free microsomal membranes isolated from the CAM. Analyses using these three assays show that calcium uptake by the CAM exhibited characteristics indicative of active transport, such as temperature dependence, saturability, energetic requirement and ion specificity. The data also show that calcium-uptake activities of the CAM increase as a function of embryonic age in a manner coincident with the increased accumulation of calcium by the developing embryo in ovo. PMID:3793786

Tuan, R S; Carson, M J; Jozefiak, J A; Knowles, K A; Shotwell, B A

1986-06-01

289

Protective effect of trimetazidine on myocardial mitochondrial function in an ex-vivo model of global myocardial ischemia  

Microsoft Academic Search

Trimetazidine is an anti-ischemic drug whose cytoprotective mechanisms are not yet fully understood (but until now mainly related to the trimetazidine-induced “metabolic shift” from lipid ?-oxidation to glucose aerobic oxidation). We studied the effect of trimetazidine on the mitochondrial function of ischemic Wistar rat hearts perfused with glucose, using a model of ex-vivo perfusion (Langendorff system). We measured the electrical

Pedro Monteiro; Ana I. Duarte; Lino M. Gonçalves; António Moreno; Luís A. Providência

2004-01-01

290

In vivo assembly of functional U7 snRNP requires RNA backbone flexibility within the Sm-binding site  

Microsoft Academic Search

Most histone precursor mRNAs (pre-mRNAs) in metazoans are matured by 3?-end cleavage directed by the U7 small nuclear ribonucleoprotein (snRNP). RNA functional groups necessary for in vivo assembly and activity of the U7 snRNP were examined by nucleotide-analog interference mapping and mutagenesis using a chimeric mouse histone H4 pre-mRNA–U7 snRNA construct that is cleaved in cis in Xenopus laevis oocytes.

Nikolay G Kolev; Joan A Steitz

2006-01-01

291

In Vivo clonal analysis reveals lineage-restricted progenitor characteristics in Mammalian kidney development, maintenance, and regeneration.  

PubMed

The mechanism and magnitude by which the mammalian kidney generates and maintains its proximal tubules, distal tubules, and collecting ducts remain controversial. Here, we use long-term in vivo genetic lineage tracing and clonal analysis of individual cells from kidneys undergoing development, maintenance, and regeneration. We show that the adult mammalian kidney undergoes continuous tubulogenesis via expansions of fate-restricted clones. Kidneys recovering from damage undergo tubulogenesis through expansions of clones with segment-specific borders, and renal spheres developing in vitro from individual cells maintain distinct, segment-specific fates. Analysis of mice derived by transfer of color-marked embryonic stem cells (ESCs) into uncolored blastocysts demonstrates that nephrons are polyclonal, developing from expansions of singly fated clones. Finally, we show that adult renal clones are derived from Wnt-responsive precursors, and their tracing in vivo generates tubules that are segment specific. Collectively, these analyses demonstrate that fate-restricted precursors functioning as unipotent progenitors continuously maintain and self-preserve the mouse kidney throughout life. PMID:24835991

Rinkevich, Yuval; Montoro, Daniel T; Contreras-Trujillo, Humberto; Harari-Steinberg, Orit; Newman, Aaron M; Tsai, Jonathan M; Lim, Xinhong; Van-Amerongen, Renee; Bowman, Angela; Januszyk, Michael; Pleniceanu, Oren; Nusse, Roel; Longaker, Michael T; Weissman, Irving L; Dekel, Benjamin

2014-05-22

292

Human ILT2 receptor associates with murine MHC class I molecules in vivo and impairs T cell function.  

PubMed

Immunoglobulin-like transcript 2 (ILT2/LILRB1/LIR1/CD85j) is an inhibitory receptor broadly expressed on leukocytes and antigen-presenting cells that recognizes HLA-class I and human cytomegalovirus UL18 proteins. The function of this receptor is to generate negative signals or to inhibit positive signals. Here, we demonstrate the model to study the function of ILT2 in vivo using a newly generated transgenic mouse expressing the human inhibitory receptor on T, B, NK, and NKT cells. ILT2 expression affects thymocyte development and targets the proximal TCR signaling pathway, resulting in long-term survival or acceptance of skin allografts. The phenotype and constitutive tyrosine phosphorylation of ILT2 in transgenic mice illustrate the possible existence of a murine ligand. We report here that H-2Db, a murine MHC class I molecule, associates with human ILT2 in vivo. This engagement with ILT2 directs effects on thymocyte development, negative regulation of TCR signaling, T cell activation, and alloimmune responses. Our finding provides support for an important inhibitory function of ILT2 in T cells in vivo and opens up strategies for targeting proximal TCR signaling for prevention of allograft rejection. PMID:16897816

Liang, Siyuan; Zhang, Wei; Horuzsko, Anatolij

2006-09-01

293

The Paf1 complex physically and functionally associates with transcription elongation factors in vivo.  

PubMed

We are using biochemical and genetic approaches to study Rtf1 and the Spt4-Spt5 complex, which independently have been implicated in transcription elongation by RNA polymerase II. Here, we report a remarkable convergence of these studies. First, we purified Rtf1 and its associated yeast proteins. Combining this approach with genetic analysis, we show that Rtf1 and Leo1, a protein of unknown function, are members of the RNA polymerase II-associated Paf1 complex. Further analysis revealed allele-specific genetic interactions between Paf1 complex members, Spt4-Spt5, and Spt16-Pob3, the yeast counterpart of the human elongation factor FACT. In addition, we independently isolated paf1 and leo1 mutations in an unbiased genetic screen for suppressors of a cold-sensitive spt5 mutation. These genetic interactions are supported by physical interactions between the Paf1 complex, Spt4-Spt5 and Spt16-Pob3. Finally, we found that defects in the Paf1 complex cause sensitivity to 6-azauracil and diminished PUR5 induction, properties frequently associated with impaired transcription elongation. Taken together, these data suggest that the Paf1 complex functions during the elongation phase of transcription in conjunction with Spt4-Spt5 and Spt16-Pob3. PMID:11927560

Squazzo, Sharon L; Costa, Patrick J; Lindstrom, Derek L; Kumer, Kathryn E; Simic, Rajna; Jennings, Jennifer L; Link, Andrew J; Arndt, Karen M; Hartzog, Grant A

2002-04-01

294

Genetic analysis of glutamatergic function in Drosophila  

SciTech Connect

Neurotransmitters are essential for communication between neurons and hence are vital in the overall integrative functioning of the nervous system. Previous work on acetylcholine metabolism in the fruit fly, Drosophila melanogaster, has also raised the possibility that transmitter metabolism may play a prominent role in either the achievement or maintenance of the normal structure of the central nervous system in this species. Unfortunately, acetylcholine is rather poorly characterized as a neurotransmitter in Drosophila; consequently, we have begun an analysis of the role of glutamate (probably the best characterized transmitter in this organism) in the formation and/or maintenance of nervous system structure. We present here the results of a series of preliminary analyses. To suggest where glutamatergic function may be localized, an examination of the spatial distribution of high affinity (/sup 3/H)-glutamate binding sites are presented. We present the results of an analysis of the spatial and temporal distribution of enzymatic activities thought to be important in the regulation of transmitter-glutamate pools (i.e., glutamate oxaloacetic transaminase, glutaminase, and glutamate dehydrogenase). To begin to examine whether mutations in any of these functions are capable of affecting glutamatergic activity, we present the results of an initial genetic analysis of one enzymatic function, glutamate oxaloacetic transaminase (GOT), chosen because of its differential distribution within the adult central nervous system and musculature.

Chase, B.A.; Kankel, D.R.

1987-01-01

295

Design and analysis of a novel mechanical loading machine for dynamic in vivo axial loading  

NASA Astrophysics Data System (ADS)

This paper describes the construction of a loading machine for performing in vivo, dynamic mechanical loading of the rodent forearm. The loading machine utilizes a unique type of electromagnetic actuator with no mechanically resistive components (servotube), allowing highly accurate loads to be created. A regression analysis of the force created by the actuator with respect to the input voltage demonstrates high linear correlation (R2 = 1). When the linear correlation is used to create dynamic loading waveforms in the frequency (0.5-10 Hz) and load (1-50 N) range used for in vivo loading, less than 1% normalized root mean square error (NRMSE) is computed. Larger NRMSE is found at increased frequencies, with 5%-8% occurring at 40 Hz, and reasons are discussed. Amplifiers (strain gauge, linear voltage displacement transducer (LVDT), and load cell) are constructed, calibrated, and integrated, to allow well-resolved dynamic measurements to be recorded at each program cycle. Each of the amplifiers uses an active filter with cutoff frequency at the maximum in vivo loading frequencies (50 Hz) so that electronic noise generated by the servo drive and actuator are reduced. The LVDT and load cell amplifiers allow evaluation of stress-strain relationships to determine if in vivo bone damage is occurring. The strain gauge amplifier allows dynamic force to strain calibrations to occur for animals of different sex, age, and strain. Unique features are integrated into the loading system, including a weightless mode, which allows the limbs of anesthetized animals to be quickly positioned and removed. Although the device is constructed for in vivo axial bone loading, it can be used within constraints, as a general measurement instrument in a laboratory setting.

Macione, James; Nesbitt, Sterling; Pandit, Vaibhav; Kotha, Shiva

2012-02-01

296

Design and analysis of a novel mechanical loading machine for dynamic in vivo axial loading.  

PubMed

This paper describes the construction of a loading machine for performing in vivo, dynamic mechanical loading of the rodent forearm. The loading machine utilizes a unique type of electromagnetic actuator with no mechanically resistive components (servotube), allowing highly accurate loads to be created. A regression analysis of the force created by the actuator with respect to the input voltage demonstrates high linear correlation (R(2) = 1). When the linear correlation is used to create dynamic loading waveforms in the frequency (0.5-10 Hz) and load (1-50 N) range used for in vivo loading, less than 1% normalized root mean square error (NRMSE) is computed. Larger NRMSE is found at increased frequencies, with 5%-8% occurring at 40 Hz, and reasons are discussed. Amplifiers (strain gauge, linear voltage displacement transducer (LVDT), and load cell) are constructed, calibrated, and integrated, to allow well-resolved dynamic measurements to be recorded at each program cycle. Each of the amplifiers uses an active filter with cutoff frequency at the maximum in vivo loading frequencies (50 Hz) so that electronic noise generated by the servo drive and actuator are reduced. The LVDT and load cell amplifiers allow evaluation of stress-strain relationships to determine if in vivo bone damage is occurring. The strain gauge amplifier allows dynamic force to strain calibrations to occur for animals of different sex, age, and strain. Unique features are integrated into the loading system, including a weightless mode, which allows the limbs of anesthetized animals to be quickly positioned and removed. Although the device is constructed for in vivo axial bone loading, it can be used within constraints, as a general measurement instrument in a laboratory setting. PMID:22380131

Macione, James; Nesbitt, Sterling; Pandit, Vaibhav; Kotha, Shiva

2012-02-01

297

Fuzzy cluster analysis of high-field functional MRI data.  

PubMed

Functional magnetic resonance imaging (fMRI) based on blood-oxygen level dependent (BOLD) contrast today is an established brain research method and quickly gains acceptance for complementary clinical diagnosis. However, neither the basic mechanisms like coupling between neuronal activation and haemodynamic response are known exactly, nor can the various artifacts be predicted or controlled. Thus, modeling functional signal changes is non-trivial and exploratory data analysis (EDA) may be rather useful. In particular, identification and separation of artifacts as well as quantification of expected, i.e. stimulus correlated, and novel information on brain activity is important for both, new insights in neuroscience and future developments in functional MRI of the human brain. After an introduction on fuzzy clustering and very high-field fMRI we present several examples where fuzzy cluster analysis (FCA) of fMRI time series helps to identify and locally separate various artifacts. We also present and discuss applications and limitations of fuzzy cluster analysis in very high-field functional MRI: differentiate temporal patterns in MRI using (a) a test object with static and dynamic parts, (b) artifacts due to gross head motion artifacts. Using a synthetic fMRI data set we quantitatively examine the influences of relevant FCA parameters on clustering results in terms of receiver-operator characteristics (ROC) and compare them with a commonly used model-based correlation analysis (CA) approach. The application of FCA in analyzing in vivo fMRI data is shown for (a) a motor paradigm, (b) data from multi-echo imaging, and (c) a fMRI study using mental rotation of three-dimensional cubes. We found that differentiation of true "neural" from false "vascular" activation is possible based on echo time dependence and specific activation levels, as well as based on their signal time-course. Exploratory data analysis methods in general and fuzzy cluster analysis in particular may help to identify artifacts and add novel and unexpected information valuable for interpretation, classification and characterization of functional MRI data which can be used to design new data acquisition schemes, stimulus presentations, neuro(physio)logical paradigms, as well as to improve quantitative biophysical models. PMID:14656487

Windischberger, Christian; Barth, Markus; Lamm, Claus; Schroeder, Lee; Bauer, Herbert; Gur, Ruben C; Moser, Ewald

2003-11-01

298

SMJ's analysis of Ising model correlation functions  

NASA Astrophysics Data System (ADS)

In a series of recent publications Sato, Miwa, and Jimbo (SMJ) have shown how to derive multispin correlation functions of the two-dimensional Ising model in the continuum, or scaling, limit by analyzing the behavior of the solutions to the two-dimensional version of the Dirac equation. The major purpose of the present work is to describe SMJ's analysis more discursively and in terms closer to that used in previous studies of the Ising model. In addition, new and more compact expressions for their basic equations are derived. A single new answer is obtained: the form of the three-spin correlation function at criticality.

Kadanoff, Leo P.; Kohmoto, Mahito

1980-05-01

299

Network approaches to the functional analysis of microbial proteins.  

PubMed

Large amounts of detailed biological data have been generated over the past few decades. Much of these data is freely available in over 1000 online databases; an enticing, but frustrating resource for microbiologists interested in a systems-level view of the structure and function of microbial cells. The frustration engendered by the need to trawl manually through hundreds of databases in order to accumulate information about a gene, protein, pathway, or organism of interest can be alleviated by the use of computational data integration to generated network views of the system of interest. Biological networks can be constructed from a single type of data, such as protein-protein binding information, or from data generated by multiple experimental approaches. In an integrated network, nodes usually represent genes or gene products, while edges represent some form of interaction between the nodes. Edges between nodes may be weighted to represent the probability that the edge exists in vivo. Networks may also be enriched with ontological annotations, facilitating both visual browsing and computational analysis via web service interfaces. In this review, we describe the construction, analysis of both single-data source and integrated networks, and their application to the inference of protein function in microbes. PMID:22114841

Hallinan, J S; James, K; Wipat, A

2011-01-01

300

Compound Ex Vivo and In Silico Method for Hemodynamic Analysis of Stented Arteries  

PubMed Central

Hemodynamic factors such as low wall shear stress have been shown to influence endothelial healing and atherogenesis in stent-free vessels. However, in stented vessels, a reliable quantitative analysis of such relations has not been possible due to the lack of a suitable method for the accurate acquisition of blood flow. The objective of this work was to develop a method for the precise reconstruction of hemodynamics and quantification of wall shear stress in stented vessels. We have developed such a method that can be applied to vessels stented in or ex vivo and processed ex vivo. Here we stented the coronary arteries of ex vivo porcine hearts, performed vascular corrosion casting, acquired the vessel geometry using micro-computed tomography and reconstructed blood flow and shear stress using computational fluid dynamics. The method yields accurate local flow information through anatomic fidelity, capturing in detail the stent geometry, arterial tissue prolapse, radial and axial arterial deformation as well as strut malapposition. This novel compound method may serve as a unique tool for spatially resolved analysis of the relationship between hemodynamic factors and vascular biology. It can further be employed to optimize stent design and stenting strategies.

Rikhtegar, Farhad; Pacheco, Fernando; Wyss, Christophe; Stok, Kathryn S.; Ge, Heng; Choo, Ryan J.; Ferrari, Aldo; Poulikakos, Dimos; Muller, Ralph; Kurtcuoglu, Vartan

2013-01-01

301

In vivo neutron activation analysis: body composition studies in health and disease  

SciTech Connect

In vivo analysis of body elements by neutron activation is an important tool in medical research. It has provided a direct quantitative measure of body composition of human beings in vivo. Basic physiological differences related to age, sex, race, and body size have been assessed by this noninvasive technique. The diagnosis and management of patients with various metabolic disorders and diseases has also been demonstrated. Two major facilities at Brookhaven are being utilized exclusively for in vivo neutron activation analysis (IVNAA) of calcium, phosphorus, sodium, chlorine, nitrogen, hydrogen, and potassium. These elements serve as the basis for a four compartment model of body composition: protein, water, mineral ash, and fat. Variations in these compartments are demonstrated in clinical research programs investigating obesity, anorexia, cancer, renal failure, osteoporosis, and normal aging. IVNAA continues to provide a unique approach to the evaluation of clinical diagnosis, efficacy of therapeutic regimens, and monitoring of the aging process. Classical balance studies usually require the patient to be admitted to a hospital for extended periods of confinement. IVNAA, however, allows for clinical management of the patient on an out-patient basis, an important aspect for treatment of chronic diseases. 25 references, 3 figures, 5 tables.

Ellis, K.J.; Cohn, S.H.

1984-01-01

302

Compound ex vivo and in silico method for hemodynamic analysis of stented arteries.  

PubMed

Hemodynamic factors such as low wall shear stress have been shown to influence endothelial healing and atherogenesis in stent-free vessels. However, in stented vessels, a reliable quantitative analysis of such relations has not been possible due to the lack of a suitable method for the accurate acquisition of blood flow. The objective of this work was to develop a method for the precise reconstruction of hemodynamics and quantification of wall shear stress in stented vessels. We have developed such a method that can be applied to vessels stented in or ex vivo and processed ex vivo. Here we stented the coronary arteries of ex vivo porcine hearts, performed vascular corrosion casting, acquired the vessel geometry using micro-computed tomography and reconstructed blood flow and shear stress using computational fluid dynamics. The method yields accurate local flow information through anatomic fidelity, capturing in detail the stent geometry, arterial tissue prolapse, radial and axial arterial deformation as well as strut malapposition. This novel compound method may serve as a unique tool for spatially resolved analysis of the relationship between hemodynamic factors and vascular biology. It can further be employed to optimize stent design and stenting strategies. PMID:23516442

Rikhtegar, Farhad; Pacheco, Fernando; Wyss, Christophe; Stok, Kathryn S; Ge, Heng; Choo, Ryan J; Ferrari, Aldo; Poulikakos, Dimos; Müller, Ralph; Kurtcuoglu, Vartan

2013-01-01

303

Development and analysis of an in vivo-compatible metabolic network of Mycobacterium tuberculosis  

PubMed Central

Background During infection, Mycobacterium tuberculosis confronts a generally hostile and nutrient-poor in vivo host environment. Existing models and analyses of M. tuberculosis metabolic networks are able to reproduce experimentally measured cellular growth rates and identify genes required for growth in a range of different in vitro media. However, these models, under in vitro conditions, do not provide an adequate description of the metabolic processes required by the pathogen to infect and persist in a host. Results To better account for the metabolic activity of M. tuberculosis in the host environment, we developed a set of procedures to systematically modify an existing in vitro metabolic network by enhancing the agreement between calculated and in vivo-measured gene essentiality data. After our modifications, the new in vivo network contained 663 genes, 838 metabolites, and 1,049 reactions and had a significantly increased sensitivity (0.81) in predicted gene essentiality than the in vitro network (0.31). We verified the modifications generated from the purely computational analysis through a review of the literature and found, for example, that, as the analysis suggested, lipids are used as the main source for carbon metabolism and oxygen must be available for the pathogen under in vivo conditions. Moreover, we used the developed in vivo network to predict the effects of double-gene deletions on M. tuberculosis growth in the host environment, explore metabolic adaptations to life in an acidic environment, highlight the importance of different enzymes in the tricarboxylic acid-cycle under different limiting nutrient conditions, investigate the effects of inhibiting multiple reactions, and look at the importance of both aerobic and anaerobic cellular respiration during infection. Conclusions The network modifications we implemented suggest a distinctive set of metabolic conditions and requirements faced by M. tuberculosis during host infection compared with in vitro growth. Likewise, the double-gene deletion calculations highlight the importance of specific metabolic pathways used by the pathogen in the host environment. The newly constructed network provides a quantitative model to study the metabolism and associated drug targets of M. tuberculosis under in vivo conditions.

2010-01-01

304

Error analysis for the in-vivo measurement of radionuclides in wounds: Monte Carlo study.  

PubMed

This paper describes calculation of error associated with the direct in-vivo measurements of radionuclides in a wound. A typical radiation injury to a hand with Am radionuclide is illustrated for error analysis. A Monte Carlo model was developed and the detector pulse spectrum studied with a custom-designed HPGe detector. A pinhole collimator was designed, and its performance with a wide area detector was studied. The results show that significant errors might propagate if the lowest energy peaks of Am are used during in vivo measurements of the wound. In comparison to that, less uncertainty was found for 26.3 and 59.5 keV gamma peaks, and those levels are recommended for estimation of wound depth and activity. PMID:21068594

Ahmed, A S M Sabbir; Capello, Kevin; Sabourin, Trevor; Kramer, Gary H

2010-12-01

305

Integrating EMR-Linked and In Vivo Functional Genetic Data to Identify New Genotype-Phenotype Associations  

PubMed Central

The coupling of electronic medical records (EMR) with genetic data has created the potential for implementing reverse genetic approaches in humans, whereby the function of a gene is inferred from the shared pattern of morbidity among homozygotes of a genetic variant. We explored the feasibility of this approach to identify phenotypes associated with low frequency variants using Vanderbilt's EMR-based BioVU resource. We analyzed 1,658 low frequency non-synonymous SNPs (nsSNPs) with a minor allele frequency (MAF)<10% collected on 8,546 subjects. For each nsSNP, we identified diagnoses shared by at least 2 minor allele homozygotes and with an association p<0.05. The diagnoses were reviewed by a clinician to ascertain whether they may share a common mechanistic basis. While a number of biologically compelling clinical patterns of association were observed, the frequency of these associations was identical to that observed using genotype-permuted data sets, indicating that the associations were likely due to chance. To refine our analysis associations, we then restricted the analysis to 711 nsSNPs in genes with phenotypes in the On-line Mendelian Inheritance in Man (OMIM) or knock-out mouse phenotype databases. An initial comparison of the EMR diagnoses to the known in vivo functions of the gene identified 25 candidate nsSNPs, 19 of which had significant genotype-phenotype associations when tested using matched controls. Twleve of the 19 nsSNPs associations were confirmed by a detailed record review. Four of 12 nsSNP-phenotype associations were successfully replicated in an independent data set: thrombosis (F5,rs6031), seizures/convulsions (GPR98,rs13157270), macular degeneration (CNGB3,rs3735972), and GI bleeding (HGFAC,rs16844401). These analyses demonstrate the feasibility and challenges of using reverse genetics approaches to identify novel gene-phenotype associations in human subjects using low frequency variants. As increasing amounts of rare variant data are generated from modern genotyping and sequence platforms, model organism data may be an important tool to enable discovery.

Mosley, Jonathan D.; Van Driest, Sara L.; Weeke, Peter E.; Delaney, Jessica T.; Wells, Quinn S.; Bastarache, Lisa; Roden, Dan M.; Denny, Josh C.

2014-01-01

306

The human immunodeficiency virus Tat proteins specifically associate with TAK in vivo and require the carboxyl-terminal domain of RNA polymerase II for function.  

PubMed

Human immunodeficiency virus types 1 and 2 encode closely related proteins, Tat-1 and Tat-2, that stimulate viral transcription. Previously, we showed that the activation domains of these proteins specifically interact in vitro with a cellular protein kinase named TAK. In vitro, TAK phosphorylates the Tat-2 but not the Tat-1 protein, a 42-kDa polypeptide of unknown identity, and the carboxyl-terminal domain (CTD) of RNA polymerase II (RNAP II). We now show that the 42-kDa substrate of TAK cochromatographs with TAK activity, suggesting that this 42-kDa polypeptide is a subunit of TAK. We also show that the Tat proteins specifically associate with TAK in vivo, since wild-type Tat-1 and Tat-2 proteins expressed in mammalian cells, but not mutant Tat proteins containing a nonfunctional activation domain, can be coimmunoprecipitated with TAK. We also mapped the in vivo phosphorylation sites of Tat-2 to the carboxyl terminus of the protein, but analysis of proteins with mutations at these sites suggests that phosphorylation is not essential for Tat-2 transactivation function. We further investigated whether the CTD of RNAP II is required for Tat function in vivo. Using plasmid constructs that express an alpha-amanitin-resistant RNAP II subunit with a truncated or full-length CTD, we found that an intact CTD is required for Tat function. These observations strengthen the proposal that the mechanism of action of Tat involves the recruitment or activation of TAK, resulting in activated transcription through phosphorylation of the CTD. PMID:8676484

Yang, X; Herrmann, C H; Rice, A P

1996-07-01

307

Measurement and Utilization of In Vivo Blood-Pressure Transfer Functions of Dog and Chicken Aortas  

Microsoft Academic Search

A method for determining the essential parameters of the aorta, namely the geometric taper, area, hoop elasticity, and effective loss factor, from in vivo pressure measurements is presented. A nonuniform hybrid model, having both geometric and elastic taper and terminated in a reflectionless impedance at the femoral bifurcation, is utilized.

Joseph J. Strano; Walter Welkowitz; Sylvan Fich

1972-01-01

308

In vivo function of the orphan nuclear receptor NR2E3 in establishing photoreceptor identity during mammalian retinal development  

PubMed Central

Rod and cone photoreceptors in mammalian retina are generated from common pool(s) of neuroepithelial progenitors. NRL, CRX and NR2E3 are key transcriptional regulators that control photoreceptor differentiation. Mutations in NR2E3, a rod-specific orphan nuclear receptor, lead to loss of rods, increased density of S-cones and supernormal S-cone-mediated vision in humans. To better understand its in vivo function, NR2E3 was expressed ectopically in the Nrl?/? retina, where post-mitotic precursors fated to be rods develop into functional S-cones similar to the human NR2E3 disease. Expression of NR2E3 in the Nrl?/? retina completely suppressed cone differentiation and resulted in morphologically rod-like photoreceptors, which were however not functional. Gene profiling of FACS-purified photoreceptors confirmed the role of NR2E3 as a strong suppressor of cone genes but an activator of only a subset of rod genes (including rhodopsin) in vivo. Ectopic expression of NR2E3 in cone precursors and differentiating S-cones of wild-type retina also generated rod-like cells. The dual regulatory function of NR2E3 was not dependent upon the presence of NRL and/or CRX, but on the timing and level of its expression. Our studies reveal a critical role of NR2E3 in establishing functional specificity of NRL-expressing photoreceptor precursors during retinal neurogenesis.

Cheng, Hong; Aleman, Tomas S.; Cideciyan, Artur V.; Khanna, Ritu; Jacobson, Samuel G.; Swaroop, Anand

2006-01-01

309

In vivo analysis of microcirculation following closed soft-tissue injury.  

PubMed

Major loss of tissue is an almost invariable consequence of severe closed soft-tissue injury. Clinically, the extent of soft-tissue trauma determines the outcome of complex injuries and significantly influences bone healing. With use of a new animal model, this study quantitatively analyzed microcirculation, i.e., nutritive perfusion and leukocyte-endothelial cell interaction, in skeletal muscle after standardized closed soft-tissue injury. By means of a computer-assisted controlled-impact technique, a severe standardized closed soft-tissue injury was induced in the left hindlimb of 28 rats. The rats were assigned to four experimental groups (n = 7 per group) that differed by time of analysis (1.5, 24, 72, and 120 hours after injury); rats that were not injured served as controls (n = 7). Intramuscular pressure was measured, and microcirculation in the rat extensor digitorum longus muscle was analyzed by in vivo fluorescence microscopy, which allowed assessment of microvascular diameters, functional capillary density, number of rolling and adherent leukocytes in venules, and microvascular permeability. Edema weight gain was quantified by the ratio of wet to dry weight of the extensor digitorum longus muscle. Microvascular perfusion of the skeletal muscle was characterized by a significant reduction in functional capillary density, which was paralleled by an increase in capillary diameter throughout the 120 hours of observation when compared with the controls. Trauma-induced inflammatory response was reflected by a markedly increased rolling and adherence of leukocytes, primarily restricted to the endothelium of postcapillary venules; this was accompanied by increased microvascular permeability, indicative of a substantial loss of endothelial integrity. The microcirculation surrounding the core of the damaged tissue area resembled that of ischemia-reperfusion injury in skeletal muscle, i.e., heterogeneous capillary perfusion, pronounced microvascular leakage, and adherence of leukocytes. Enhanced vascular leakage and leukocyte adherence (24-72 hours after injury) coincided with the maximum intramuscular pressure (which was not indicative of compartment syndrome) and edema formation. These results demonstrate that initial changes, leading to ultimate tissue death, after closed soft-tissue injury are caused on the microcirculatory level. This standardized model provides further insight into microvascular pathophysiology and cellular interactions following closed soft-tissue injury. Thus, it is an adequate tool for testing novel therapeutic interventions. PMID:10569476

Schaser, K D; Vollmar, B; Menger, M D; Schewior, L; Kroppenstedt, S N; Raschke, M; Lübbe, A S; Haas, N P; Mittlmeier, T

1999-09-01

310

Biosensors for functional food safety and analysis.  

PubMed

The importance of safety and functionality analysis of foodstuffs and raw materials is supported by national legislations and European Union (EU) directives concerning not only the amount of residues of pollutants and pathogens but also the activity and content of food additives and the health claims stated on their labels. In addition, consumers' awareness of the impact of functional foods' on their well-being and their desire for daily healthcare without the intake pharmaceuticals has immensely in recent years. Within this picture, the availability of fast, reliable, low cost control systems to measure the content and the quality of food additives and nutrients with health claims becomes mandatory, to be used by producers, consumers and the governmental bodies in charge of the legal supervision of such matters. This review aims at describing the most important methods and tools used for food analysis, starting with the classical methods (e.g., gas-chromatography GC, high performance liquid chromatography HPLC) and moving to the use of biosensors-novel biological material-based equipments. Four types of bio-sensors, among others, the novel photosynthetic proteins-based devices which are more promising and common in food analysis applications, are reviewed. A particular highlight on biosensors for the emerging market of functional foods is given and the most widely applied functional components are reviewed with a comprehensive analysis of papers published in the last three years; this report discusses recent trends for sensitive, fast, repeatable and cheap measurements, focused on the detection of vitamins, folate (folic acid), zinc (Zn), iron (Fe), calcium (Ca), fatty acids (in particular Omega 3), phytosterols and phytochemicals. A final market overview emphasizes some practical aspects ofbiosensor applications. PMID:21520718

Lavecchia, Teresa; Tibuzzi, Arianna; Giardi, Maria Teresa

2010-01-01

311

Ex Vivo Expansion of Functional Human UCB-HSCs/HPCs by Coculture with AFT024-hkirre Cells  

PubMed Central

Kiaa1867 (human Kirre, hKirre) has a critical role in brain development and/or maintenance of the glomerular slit diaphragm in kidneys. Murine homolog of this gene, mKirre expressed in OP9 and AFT024 cells could support hematopoietic stem cells/hematopoietic progenitor cells (HSC/HPC) expansion in vitro. HKirre is also expressed in human FBMOB-hTERT cell line and fetal liver fibroblast-like cells but its function has remained unclear. In this paper, we cloned a hKirre gene from human fetal liver fibroblast-like cells and established a stably overexpressing hKirre-AFT024 cell line. Resultant cells could promote self-renewal and ex vivo expansion of HSCs/HPCs significantly higher than AFT024-control cells transformed with mock plasmid. The Expanded human umbilical cord blood (hUCB) CD34+ cells retained the capacity of multipotent differentiation as long as 8 weeks and successfully repopulated the bone marrow of sublethally irradiated NOD/SCID mice, which demonstrated the expansion of long-term primitive transplantable HSCs/HPCs. Importantly, hkirre could upregulate the expressions of Wnt-5A, BMP4, and SDF-1 and downregulate TGF-? with other hematopoietic growth factors. By SDS-PAGE and Western Blot analysis, a ~89?kDa protein in total lysate of AFT024-hKirre was identified. Supernatants from AFT024-hkirre could also support CD34+CD38? cells expansion. These results demonstrated that the AFT024-hKirre cells have the ability to efficiently expand HSCs/HPCs.

Khan, Muti ur Rehman; Ali, Ijaz; Jiao, Wei; Wang, Yun; Masood, Saima; Yousaf, Muhammad Zubair; Javaid, Aqeel; Ahmad, Shafique; Feng, Meifu

2014-01-01

312

Ex vivo expansion of functional human UCB-HSCs/HPCs by coculture with AFT024-hkirre cells.  

PubMed

Kiaa1867 (human Kirre, hKirre) has a critical role in brain development and/or maintenance of the glomerular slit diaphragm in kidneys. Murine homolog of this gene, mKirre expressed in OP9 and AFT024 cells could support hematopoietic stem cells/hematopoietic progenitor cells (HSC/HPC) expansion in vitro. HKirre is also expressed in human FBMOB-hTERT cell line and fetal liver fibroblast-like cells but its function has remained unclear. In this paper, we cloned a hKirre gene from human fetal liver fibroblast-like cells and established a stably overexpressing hKirre-AFT024 cell line. Resultant cells could promote self-renewal and ex vivo expansion of HSCs/HPCs significantly higher than AFT024-control cells transformed with mock plasmid. The Expanded human umbilical cord blood (hUCB) CD34(+) cells retained the capacity of multipotent differentiation as long as 8 weeks and successfully repopulated the bone marrow of sublethally irradiated NOD/SCID mice, which demonstrated the expansion of long-term primitive transplantable HSCs/HPCs. Importantly, hkirre could upregulate the expressions of Wnt-5A, BMP4, and SDF-1 and downregulate TGF- ? with other hematopoietic growth factors. By SDS-PAGE and Western Blot analysis, a ~89?kDa protein in total lysate of AFT024-hKirre was identified. Supernatants from AFT024-hkirre could also support CD34(+)CD38(-) cells expansion. These results demonstrated that the AFT024-hKirre cells have the ability to efficiently expand HSCs/HPCs. PMID:24719861

Khan, Muti ur Rehman; Ali, Ijaz; Jiao, Wei; Wang, Yun; Masood, Saima; Yousaf, Muhammad Zubair; Javaid, Aqeel; Ahmad, Shafique; Feng, Meifu

2014-01-01

313

Medial Cochlear Efferent Function: A Theoretical Analysis  

NASA Astrophysics Data System (ADS)

Since the discovery of the cochlear efferent system, many hypotheses have been put forth for its function. These hypotheses for its function range from protecting the cochlea from over stimulation to improving the detection of sounds in noise. It is known that the medial efferent system innervates the outer hair cells and that stimulation of this system reduces basilar membrane and auditory nerve sensitivity which suggests that this system acts to decrease the gain of the cochlear amplifier. Here I present modeling results as well as analysis of published experimental data that suggest that the function of the medial efferent reflex is to decrease the cochlear amplifier gain by just the right amount so that the nonlinearity in the basilar membrane response lines up perfectly with the inner hair cell nonlinear transduction process to produce a hair cell receptor potential that is proportional to the logarithm of the sound pressure level.

Mountain, David C.

2011-11-01

314

Isolation and ex vivo characterization of the immunophenotype and function of microglia/macrophage populations in normal dog retina.  

PubMed

Microglia are the primary resident immune cells of the retina and are involved in the pathogenesis of various retinal diseases. In this study, we optimized experimental conditions to isolate microglia from canine retinas and characterized ex vivo their immunophenotype and function using flow cytometry (FACS). The most suitable protocol included a mechanical dissociation of the retina and an enzymatic digestion using DNAse and collagenase. Extraction was carried out by density gradient centrifugation, and retinal microglia accumulated on distinct interfaces of 1.072 and 1.088 g/mL of a Percoll gradient. Immunophenotypical characterization was performed with monoclonal antibodies CD11b, CD11c, CD18, CD45, CD44, B7-1 (CD80), B7-2 (CD86), CD1c, ICAM-1 (CD54), CD14, MHCI, MHCII, CD68, CD3, CD4, CD8?, and CD21. The most prevalent microglia population in the normal canine retina is CD11b(high)CD45(low). Functionally, retinal microglia exhibited phagocytosis and reactive oxygen species (ROS) generation activities. To conclude, ex vivo examinations of retinal microglia are feasible and possibly reflect the in vivo conditions, avoiding artifacts observed in tissue culture. The established method will be relevant to examine microglia from diseased canine retinas in order to elucidate their roles in degenerative processes. PMID:24664716

Genini, Sem; Beltran, William A; Stein, Veronika M; Aguirre, Gustavo D

2014-01-01

315

40 CFR 798.5385 - In vivo mammalian bone marrow cytogenetics tests: Chromosomal analysis.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false In vivo mammalian bone marrow cytogenetics tests: Chromosomal...798.5385 In vivo mammalian bone marrow cytogenetics tests: Chromosomal...a) Purpose. The in vivo bone marrow cytogenetic test is a...

2009-07-01

316

40 CFR 798.5385 - In vivo mammalian bone marrow cytogenetics tests: Chromosomal analysis.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true In vivo mammalian bone marrow cytogenetics tests: Chromosomal...798.5385 In vivo mammalian bone marrow cytogenetics tests: Chromosomal...a) Purpose. The in vivo bone marrow cytogenetic test is a...

2010-07-01

317

In vivo evaluation of a vibration analysis technique for the per-operative monitoring of the fixation of hip prostheses  

PubMed Central

Background The per-operative assessment of primary stem stability may help to improve the performance of total hip replacement. Vibration analysis methods have been successfully used to assess dental implant stability, to monitor fracture healing and to measure bone mechanical properties. The objective of the present study was to evaluate in vivo a vibration analysis-based endpoint criterion for the insertion of the stem by successive surgeon-controlled hammer blows. Methods A protocol using a vibration analysis technique for the characterisation of the primary bone-prosthesis stability was tested in 83 patients receiving a custom-made, intra-operatively manufactured stem prosthesis. Two groups were studied: one (n = 30) with non cemented and one (n = 53) with partially cemented stem fixation. Frequency response functions of the stem-femur system corresponding to successive insertion stages were compared. Results The correlation coefficient between the last two frequency response function curves was above 0.99 in 86.7% of the non cemented cases. Lower values of the final correlation coefficient and deviations in the frequency response pattern were associated with instability or impending bone fracture. In the cases with a partially cemented stem an important difference in frequency response function between the final stage of non cemented trial insertion and the final cemented stage was found in 84.9% of the cases. Furthermore, the frequency response function varied with the degree of cement curing. Conclusion The frequency response function change provides reliable information regarding the stability evolution of the stem-femur system during the insertion. The protocol described in this paper can be used to accurately detect the insertion end point and to reduce the risk for intra-operative fracture.

Pastrav, Leonard C; Jaecques, Siegfried VN; Jonkers, Ilse; Perre, Georges Van der; Mulier, Michiel

2009-01-01

318

Thiobacillus ferrooxidans tyrosyl-tRNA synthetase functions in vivo in Escherichia coli.  

PubMed Central

The tyrosyl-tRNA synthetase gene (tyrZ) from Thiobacillus ferrooxidans, an acidophilic, autotrophic, gram-negative bacterium that participates in bioleaching of minerals, was cloned and sequenced. The encoded polypeptide (TyrRZ) is 407 amino acids in length (molecular mass; 38 kDa). The predicted protein sequence has an extensive overall identity (44%) to the sequence of the protein encoded by the Bacillus subtilus tyrZ gene, one of the two genes encoding tyrosyl-tRNA synthetases in this microorganism. Alignment with Escherichia coli TyrRS revealed limited overall identity (24%), except in the regions of the signature sequence for class I aminoacyl-tRNA synthetases. Complementation of an E. coli strain with a thermosensitive mutation in TyrRS showed that the protein encoded by the T. ferrooxidans tyrZ gene is functional and recognizes the E. coli tRNA(Tyr) as a substrate. TyrZ is a single-copy gene as revealed by Southern blot analysis. The gene was localized upstream from the putative promoters of the rrnT2 ribosomal RNA operon. Although no rho-independent transcription terminator was found between the two genes, a 1.3-kb RNA hybridized to a DNA probe derived from the tyrZ gene. The functional relationship between these two transcription units is discussed. Images

Salazar, O.; Sagredo, B.; Jedlicki, E.; Soll, D.; Weygand-Durasevic, I.; Orellana, O.

1994-01-01

319

Therapeutic nanomedicine based on dual-intelligent functionalized gold nanoparticles for cancer imaging and therapy in vivo.  

PubMed

A novel strategy to construct a therapeutic system based on functionalized AuNPs which can specifically respond to tumor microenvironment was reported. In the therapeutic system, doxorubicin was conjugated to AuNPs via thiol-Au bond by using a peptide substrate, CPLGLAGG, which can be specifically cleaved by the protease. In vivo study shows that after injection of the functionalized AuNPs to the tumor-bearing mice, the over-expressed protease of MMP-2 in tumor tissue and intracellular GSH can lead to the rapid release of the anti-tumor drug (doxorubicin) from the functionalized AuNPs to inhibit tumor growth and realize fluorescently imaging simultaneously. The functionalized AuNPs with tumor-triggered drug release property can further improve the efficacy and reduce side effects significantly. PMID:23932289

Chen, Wei-Hai; Xu, Xiao-Ding; Jia, Hui-Zhen; Lei, Qi; Luo, Guo-Feng; Cheng, Si-Xue; Zhuo, Ren-Xi; Zhang, Xian-Zheng

2013-11-01

320

In-Vivo functional optical-resolution photoacoustic microscopy with stimulated Raman scattering fiber-laser source.  

PubMed

In this paper a multi-wavelength optical-resolution photoacoustic microscopy (OR-PAM) system using stimulated Raman scattering is demonstrated for both phantom and in vivo imaging. A 1-ns pulse width ytterbium-doped fiber laser is coupled into a single-mode polarization maintaining fiber. Discrete Raman-shifted wavelength peaks extending to nearly 800 nm are generated with pulse energies sufficient for OR-PAM imaging. Bandpass filters are used to select imaging wavelengths. A dual-mirror galvanometer system was used to scan the focused outputs across samples of carbon fiber networks, 200?m dye-filled tubes, and Swiss Webster mouse ears. Photoacoustic signals were collected in transmission mode and used to create maximum amplitude projection C-scan images. Double dye experiments and in vivo oxygen saturation estimation confirmed functional imaging potential. PMID:24575346

Hajireza, Parsin; Forbrich, Alexander; Zemp, Roger

2014-02-01

321

Structure and Function of RNase AS, a Polyadenylate-Specific Exoribonuclease Affecting Mycobacterial Virulence In Vivo.  

PubMed

The cell-envelope of Mycobacterium tuberculosis plays a key role in bacterial virulence and antibiotic resistance. Little is known about the molecular mechanisms of regulation of cell-envelope formation. Here, we elucidate functional and structural properties of RNase AS, which modulates M. tuberculosis cell-envelope properties and strongly impacts bacterial virulence in vivo. The structure of RNase AS reveals a resemblance to RNase T from Escherichia coli, an RNase of the DEDD family involved in RNA maturation. We show that RNase AS acts as a 3'-5'-exoribonuclease that specifically hydrolyzes adenylate-containing RNA sequences. Also, crystal structures of complexes with AMP and UMP reveal the structural basis for the observed enzyme specificity. Notably, RNase AS shows a mechanism of substrate recruitment, based on the recognition of the hydrogen bond donor NH2 group of adenine. Our work opens a field for the design of drugs able to reduce bacterial virulence in vivo. PMID:24704253

Romano, Maria; van de Weerd, Robert; Brouwer, Femke C C; Roviello, Giovanni N; Lacroix, Ruben; Sparrius, Marion; van den Brink-van Stempvoort, Gunny; Maaskant, Janneke J; van der Sar, Astrid M; Appelmelk, Ben J; Geurtsen, Jeroen J; Berisio, Rita

2014-05-01

322

Functional analysis of HapMap SNPs.  

PubMed

Genome-wide association studies (GWAS) have successfully identified many genetic variants associated with complex diseases and traits. However, functional consequence of genetic variants studied in GWAS is not yet fully investigated, which would hinder the application of GWAS. We therefore performed a systematic functional analysis of HapMap SNPs, which have been most commonly used as the reference panel for GWAS. Our study highlights several characteristics of HapMap SNPs and identifies subsets of genetic variants with interesting functional implication. The results show that HapMap SNPs have good coverage within RefSeq genes, especially within known disease-related genes. On the other hand, only a small percentage of SNPs are non-synonymous SNPs while many SNPs are actually located at gene deserts. Moreover, many functionally important variants are not yet still interrogated. A redesigned SNP reference panel with additional functionally important variants would be useful to identify disease-causal variants in the future genome-wide studies. PMID:23041558

Liu, Ching-Ti; Lin, Houwei; Lin, Honghuang

2012-12-15

323

Functionalized single-walled carbon nanotubes containing traces of iron as new negative MRI contrast agents for in vivo imaging.  

PubMed

Single-walled carbon nanotubes (SWCNTs) containing traces of iron oxide were functionalized by noncovalent lipid-PEG or covalent carboxylic acid function to supply new efficient MRI contrast agents for in vitro and in vivo applications. Longitudinal (r(1)) and transversal (r(2)) water proton relaxivities were measured at 300?MHz, showing a stronger T(2) feature as an MRI contrast agent (r(2)/r(1) ?=?190 for CO(2) H functionalisation). The r(2) relaxivity was demonstrated to be correlated to the presence of iron oxide in the SWNT-carboxylic function COOH, in comparison to iron-free ones. Biodistribution studies on mice after a systemic injection showed a negative MRI contrast in liver, suggesting the presence of the nanotubes in this organ until 48?h after i.v. injection. The presence of carbon nanotubes in liver was confirmed after ex vivo carbon extraction. Finally, cytotoxicity studies showed no apparent effect owing to the presence of the carbon nanotubes. The functionalized carbon nanotubes were well tolerated by the animals at the dose of 10?µg?g(-1) body weight. PMID:22434627

Doan, Bich-Thuy; Seguin, Johanne; Breton, Marie; Le Beherec, Ronan; Bessodes, Michel; Rodríguez-Manzo, Julio A; Banhart, Florian; Beloeil, Jean-Claude; Scherman, Daniel; Richard, Cyrille

2012-01-01

324

Regulation of granulocyte function by hyaluronic acid. In vitro and in vivo effects on phagocytosis, locomotion, and metabolism.  

PubMed Central

Hyaluronic acid (HA) stimulated the function of polymorphonucler leukocytes (PMN) both in vitro and in vivo. Stimulation in vitro was achieved by the incubation of PMN and HA in heparinized whole blood at concentrations of HA between 5 and 500 microgram/liter. The stimulation of the PMN function was demonstrated by an increase rate of phagocytosis of complement- and/or immunoglobulin (Ig)G-coated latex particles, increased adherence to nylon wool, increased random migration and chemotactic response, increased chemiluminescence during phagocytosis, and raised levels of intracellular ATP. The effect of HA in vivo was demonstrated, after subcutaneous administration of HA (5-20 mg) to healthy volunteers, by an enhanced rate of phagocytosis of the subsequently isolated neutrophils. The duration of the effect of one administration was approximately 1 wk with maximum effect on days 2-4. HA injections to patients with increased susceptibility to bacterial infections and impaired neutrophil function demonstrated an enhanced neutrophil function also in these individuals. HA may therefore be a new principle by which resistance to infections can be enhanced.

Hakansson, L; Hallgren, R; Venge, P

1980-01-01

325

Clinical and microstructural analysis of patients with hyper-reflective corneal endothelial nuclei imaged by in vivo confocal microscopy.  

PubMed

The purpose of this study was to determine the significance of hyper-reflective corneal endothelial nuclei imaged by in vivo confocal microscopy. A retrospective analysis was performed using a database of 505 patients that had undergone in vivo confocal microscopy of the cornea. All subjects with hyper-reflective endothelial nuclei were identified and these images were analysed to determine corneal endothelial cell density and morphology. The clinical notes of these patients were reviewed and corresponding data regarding corneal thickness was obtained from a related database of Orbscan II pachymetry. Hyper-reflective endothelial nuclei were identified in 41 eyes of 39 (7.7%) patients. Diagnoses included previous cataract surgery or penetrating keratoplasty, posterior polymorphous dystrophy, Fuchs' endothelial dystrophy and irido-corneal endothelial syndrome. No patients with clinically normal corneas exhibited bright endothelial nuclei. The mean endothelial cell density in this group was 1325+/-872 cells mm(-2) and endothelial density was below age-adjusted normal values in 69.2% of patients. Both cellular polymegathism (coefficient of variation of cell area 33.9+/-7.4%) and cellular pleomorphism were noted (51.8+/-9.0% hexagonal cells). The mean central corneal thickness was 582+/-52 microm. There was no significant difference in endothelial density and morphology compared to cases that had low endothelial density but did not exhibit bright nuclei. In conclusion, this study is the first to investigate the significance of bright endothelial nuclei detected by in vivo confocal microscopy. The strong association with corneal disease states suggests that the most likely explanation for this appearance is the alteration in cellular/nuclear morphology, composition or function. PMID:16359661

Patel, Dipika V; Phua, Yun Shan; McGhee, Charles N J

2006-04-01

326

In vivo mutation analysis using the ?X174 transgenic mouse and comparisons with other transgenes and endogenous genes.  

PubMed

The ?X174 transgenic mouse was first developed as an in vivo Ames test, detecting base pair substitution (bps) at a single bp in a reversion assay. A forward mutational assay was also developed, which is a gain of function assay that also detects bps exclusively. Later work with both assays focused on establishing that a mutation was fixed in vivo using single-burst analysis: determining the number of mutant progeny virus from an electroporated cell by dividing the culture into aliquots before scoring mutants. We review results obtained from single-burst analysis, including testing the hypothesis that high mutant frequencies (MFs) of G:C to A:T mutation recovered by transgenic targets include significant numbers of unrepaired G:T mismatches. Comparison between the ?X174 and lacI transgenes in mouse spleen indicates that the spontaneous bps mutation frequency per nucleotide (mf(n)) is not significantly lower for ?X174 than for lacI; the response to ENU is also comparable. For the lacI transgene, the spontaneous bps mf(n) is highly age-dependent up to 12 weeks of age and the linear trend extrapolates at conception to a frequency close to the human bps mf(n) per generation of 1.7 × 10(-8). Unexpectedly, we found that the lacI somatic (spleen) bps mf(n) per cell division at early ages was estimated to be the same as for the human germ-line. The bps mf(n) in bone marrow for the gpt transgene is comparable to spleen for the lacI and ?X174 transgenes. We conclude that the G:C to A:T transition is characteristic of spontaneous in vivo mutation and that the MFs measured in these transgenes at early ages reflect the expected accumulation of in vivo mutation typical of endogenous mammalian mutation rates. However, spontaneous and induced mf(n)s per nucleotide for the cII gene in spleen are 5-10 times higher than for these other transgenes. PMID:20637298

Valentine, Carrie R; Delongchamp, Robert R; Pearce, Mason G; Rainey, Heather F; Dobrovolsky, Vasily N; Malling, Heinrich V; Heflich, Robert H

2010-12-01

327

Surface Based Analysis of Diffusion Orientation for Identifying Architectonic Domains in the In Vivo Human Cortex  

PubMed Central

Diffusion tensor MRI is sensitive to the coherent structure of brain tissue and is commonly used to study large-scale white matter structure. Diffusion in grey matter is more isotropic, however, several groups have observed coherent patterns of diffusion anisotropy within the cerebral cortical grey matter. We extend the study of cortical diffusion anisotropy by relating it to the local coordinate system of the folded cerebral cortex. We use 1mm and sub-millimeter isotropic resolution diffusion imaging to perform a laminar analysis of the principal diffusion orientation, fractional anisotropy, mean diffusivity and partial volume effects. Data from 6 in vivo human subjects, a fixed human brain specimen and an anesthetized macaque were examined. Large regions of cortex show a radial diffusion orientation. In vivo human and macaque data displayed a sharp transition from radial to tangential diffusion orientation at the border between primary motor and somatosensory cortex, and some evidence of tangential diffusion in secondary somatosensory cortex and primary auditory cortex. Ex vivo diffusion imaging in a human tissue sample showed some tangential diffusion orientation in S1 but mostly radial diffusion orientations in both M1 and S1.

McNab, Jennifer A.; Polimeni, Jonathan R.; Wang, Ruopeng; Augustinack, Jean C.; Fujimoto, Kyoko; Player, Allison; Janssens, Thomas; Farivar, Reza; Folkerth, Rebecca D.; Vanduffel, Wim; Wald, Lawrence L.

2012-01-01

328

Surface based analysis of diffusion orientation for identifying architectonic domains in the in vivo human cortex.  

PubMed

Diffusion tensor MRI is sensitive to the coherent structure of brain tissue and is commonly used to study large-scale white matter structure. Diffusion in gray matter is more isotropic, however, several groups have observed coherent patterns of diffusion anisotropy within the cerebral cortical gray matter. We extend the study of cortical diffusion anisotropy by relating it to the local coordinate system of the folded cerebral cortex. We use 1mm and sub-millimeter isotropic resolution diffusion imaging to perform a laminar analysis of the principal diffusion orientation, fractional anisotropy, mean diffusivity and partial volume effects. Data from 6 in vivo human subjects, a fixed human brain specimen and an anesthetized macaque were examined. Large regions of cortex show a radial diffusion orientation. In vivo human and macaque data displayed a sharp transition from radial to tangential diffusion orientation at the border between primary motor and somatosensory cortex, and some evidence of tangential diffusion in secondary somatosensory cortex and primary auditory cortex. Ex vivo diffusion imaging in a human tissue sample showed some tangential diffusion orientation in S1 but mostly radial diffusion orientations in both M1 and S1. PMID:23247190

McNab, Jennifer A; Polimeni, Jonathan R; Wang, Ruopeng; Augustinack, Jean C; Fujimoto, Kyoko; Stevens, Allison; Triantafyllou, Christina; Janssens, Thomas; Farivar, Reza; Folkerth, Rebecca D; Vanduffel, Wim; Wald, Lawrence L

2013-04-01

329

Ex Vivo Analysis of Human Memory B Lymphocytes Specific for A and B Influenza Hemagglutinin by Polychromatic Flow-Cytometry  

PubMed Central

Understanding the impact that human memory B-cells (MBC), primed by previous infections or vaccination, exert on neutralizing antibody responses against drifted influenza hemagglutinin (HA) is key to design best protective vaccines. A major obstacle to these studies is the lack of practical tools to analyze HA-specific MBCs in human PBMCs ex vivo. We report here an efficient method to identify MBCs carrying HA-specific BCR in frozen PBMC samples. By using fluorochrome-tagged recombinant HA baits, and vaccine antigens from mismatched influenza strains to block BCR-independent binding, we developed a protocol suitable for quantitative, functional and molecular analysis of single MBCs specific for HA from up to two different influenza strains in the same tube. This approach will permit to identify the naive and MBC precursors of plasmablasts and novel MBCs appearing in the blood following infection or vaccination, thus clarifying the actual contribution of pre-existing MBCs in antibody responses against novel influenza viruses. Finally, this protocol can allow applying high throughput deep sequencing to analyze changes in the repertoire of HA+ B-cells in longitudinal samples from large cohorts of vaccinees and infected subjects with the ultimate goal of understanding the in vivo B-cell dynamics driving the evolution of broadly cross-protective antibody responses.

Bardelli, Monia; Buricchi, Francesca; Tavarini, Simona; Sammicheli, Chiara; Nuti, Sandra; Degl'Innocenti, Elena; Isnardi, Isabelle; Fragapane, Elena; Del Giudice, Giuseppe; Castellino, Flora; Galli, Grazia

2013-01-01

330

A Note on Population Analysis of Dissolution-Absorption Models using the Inverse Gaussian Function  

PubMed Central

Since conventional absorption models often fail to describe plasma concentration–time profiles following oral administration, empirical input functions such as the inverse Gaussian function (IG) have been successfully used. The purpose of this note is to extend this model by adding a first-order absorption process and to demonstrate the application of population analysis using maximum likelihood estimation via the EM algorithm (implemented in ADAPT 5). In one example, the analysis of bioavailability data of an extended release formulation, the mean dissolution times estimated in vivo and in vitro with the use of the IG are well in accordance suggesting that the IG indeed accounts for the in vivo dissolution process. In the other example, the kinetics of trapidil in patients with liver disease, the absorption/dissolution parameters are characterized by a high interindividual variability. Adding a first-order absorption process to the IG improved the fit in both cases.

Wang, Jian; Weiss, Michael; D'Argenio, David Z.

2009-01-01

331

A Multifunctional Turnip Crinkle Virus Replication Enhancer Revealed by in vivo Functional SELEX  

Microsoft Academic Search

The motif1-hairpin (M1H), located on (?)-strands of Turnip Crinkle Virus (TCV)-associated satellite RNA C (satC), is a replication enhancer and recombination hotspot. Results of in vivo genetic selection (SELEX: systematic evolution of ligands by exponential enrichment), where 28 bases of the M1H were randomized and then subjected to selection in plants, revealed that most winners contained one to three short

Guohua Zhang; Anne E Simon

2003-01-01

332

Simultaneous estimation of physiological parameters and the input function - in vivo PET data  

Microsoft Academic Search

Dynamic imaging with positron emission tomography (PET) is widely used for the in-vivo measurement of the regional cerebral metabolic rate for glucose (rCMRGlc) with [ 18F]fluorodeoxy-D-glucose (FDG), and is used for the clinical evaluation of neurological diseases. However, in addition to the acquisition of dynamic images, continuous arterial blood sampling is the conventional method of obtaining the tracer time-activity curve

Koon-pong Wong; David Dagan Feng; Steven R. Meikle; Michael J. Fulham

2001-01-01

333

In vivo and in vitro effects of aluminum treatment on rat liver mitochondrial function  

Microsoft Academic Search

This study examines the effect on mitochondrial respiration and permeability of in vivo and in vitro aluminium (Al) exposure.\\u000a Rats were treated intraperitoneally with AlCl3 to achieve serum and liver Al concentrations comparable to those seen in Al-related disorders. Mitochondria isolated from\\u000a Al-treated rats had higher (pp<0.05) state 3 respiration, respiratory control (RCR), and ADP\\/O ratio (succinate substrate), and greater

Maria Burnatowska-Hledin; Karl V. Ebner; Gilbert H. Mayor

1986-01-01

334

Quantitative proteomic analysis of Myc oncoprotein function  

PubMed Central

This study applies a new quantitative proteomics technology to the analysis of the function of the Myc oncoprotein in mammalian cells. Employing isotope-coded affinity tag (ICATTM) reagent labeling and tandem mass spectrometry, the global pattern of protein expression in rat myc-null cells was compared with that of myc-plus cells (myc-null cells in which myc has been introduced) to generate a differential protein expression catalog. Expression differences among many functionally related proteins were identified, including reduction of proteases, induction of protein synthesis pathways and upregulation of anabolic enzymes in myc-plus cells, which are predicted to lead to increased cell mass (cell growth). In addition, reduction in the levels of adhesion molecules, actin network proteins and Rho pathway proteins were observed in myc-plus cells, leading to reduced focal adhesions and actin stress fibers as well as altered morphology. These effects are dependent on the highly conserved Myc Box II region. Our results reveal a novel cytoskeletal function for Myc and indicate the feasibility of quantitative whole-proteome analysis in mammalian cells.

Shiio, Yuzuru; Donohoe, Sam; Yi, Eugene C.; Goodlett, David R.; Aebersold, Ruedi; Eisenman, Robert N.

2002-01-01

335

Functional characterization of equine neutrophils in response to calcium ionophore A23187 and phorbol myristate acetate ex vivo.  

PubMed

Equine neutrophils (PMN) play a critical role in inflammatory processes in horses. The objective of this study was to characterize equine PMN function ex vivo following stimulation with calcium ionophore A23187 (A23187) and phorbol myristate acetate (PMA). These stimulants trigger different branches of the PMN activation process that occurs in vivo. Equine PMN were isolated from the whole blood of six clinically normal geldings using a one-step discontinuous Percoll gradient technique. Neutrophil aggregation, degranulation, and superoxide anion production were evaluated in assay systems which had previously been established to quantitate PMN function. Dose-response curves for A23187 and PMA were derived for the three functions. Results indicate that equine PMN aggregation and superoxide anion production are more responsive to activation by PMA as the maximum change in percent transmittance and maximum nanomoles of superoxide anion produced following PMA stimulation (60.8% and 10.4 nmol per 10(6) cells, respectively) were greater than those values stimulated by A23187 (41.5% and 5.2 nmol per 10(6) cells, respectively). However, degranulation was found to be more responsive to A23187 stimulation (maximum percent degranulation: 56.1%) than to PMA stimulation (maximum percent degranulation: 30.7%). Dose-response curves following A23187 and PMA stimulation revealed that superoxide anion production had the lowest threshold concentration among the three functions. Degranulation had the highest threshold concentration among the three functions for both stimulants. Results indicate that equine PMN functions differ in their dependence on second messengers in the activation pathway. These functions also occur in a dose-dependent manner and differ in the threshold concentrations required for their stimulation. PMID:9223228

Moore, T; Wilcke, J; Chilcoat, C; Eyre, P; Crisman, M

1997-05-01

336

Functional Analysis of Arabidopsis Sucrose Transporters  

SciTech Connect

Sucrose is the main photosynthetic product that is transported in the vasculature of plants. The long-distance transport of carbohydrates is required to support the growth and development of net-importing (sink) tissues such as fruit, seeds and roots. This project is focused on understanding the transport mechanism sucrose transporters (SUTs). These are proton-coupled sucrose uptake transporters (membrane proteins) that are required for transport of sucrose in the vasculature and uptake into sink tissues. The accomplishments of this project included: 1) the first analysis of substrate specificity for any SUT. This was accomplished using electrophysiology to analyze AtSUC2, a sucrose transporter from companion cells in Arabidopsis. 2) the first analysis of the transport activity for a monocot SUT. The transport kinetics and substrate specificity of HvSUT1 from barley were studied. 3) the first analysis of a sucrose transporter from sugarcane. and 4) the first analysis of transport activity of a sugar alcohol transporter homolog from plants, AtPLT5. During this period four primary research papers, funded directly by the project, were published in refereed journals. The characterization of several sucrose transporters was essential for the current effort in the analysis of structure/function for this gene family. In particular, the demonstration of strong differences in substrate specificity between type I and II SUTs was important to identify targets for site-directed mutagenesis.

John M. Ward

2009-03-31

337

Objective clinical evaluation of function. Gait analysis.  

PubMed

Automated gait analysis allows us to document and quantify objectively normal gait, functional deficits, and patient response to therapeutic intervention. Instrumentation for this analysis at the Mayo Clinic Gait Laboratory includes three-dimensional electrogoniometers for measurement of relative joint rotation at the hip, knee, and ankle; footswitches that record foot-floor contact sequences; instrumented mats that measure step length and width; piezoelectric force plates for measurement of floor reaction forces; and two walkways that simulate a variety of ground conditions. We use a DEC-PDP 11/34 computer for acquisition, storage, and analysis of data and for generation of a gait report form that displays a patient's results relative to normal and previous evaluations. Applications of these techniques include assessment of function preoperative and postoperative total joint arthroplasty, quantification of gait faults, and documentation of effectiveness of exercise and gait training techniques. We have demonstrated the reliability of the techniques, accumulated a sizeable normal data bank, and developed a concise, effective data summary for communication with referring practitioners. PMID:6548815

Laughman, R K; Askew, L J; Bleimeyer, R R; Chao, E Y

1984-12-01

338

In vivo Prompt Gamma Neutron Activation Analysis Facility for Total Body Nitrogen and Cd  

SciTech Connect

A Prompt Gamma Neutron Activation Analysis (PGNAA) system has been designed and constructed to measure the total body nitrogen and Cd for in vivo studies. An aqueous solution of KNO{sub 3} was used as phantom for system calibration. The facility has been used to monitor total body nitrogen (TBN) of mice and found that is related to their diet. Some mice swallowed diluted water with Cl{sub 2}Cd, and the presence of Cd was detected in the animals. The minimum Cd concentration that the system can detect was 20 ppm.

Munive, Marco; Revilla, Angel [Instituto Peruano de Energia Nuclear, Av. Canada 1470, Lima 41 (Peru); Solis, Jose L. [Instituto Peruano de Energia Nuclear, Av. Canada 1470, Lima 41 (Peru); Facultad de Ciencias, Universidad Nacional de Ingenieria, Av. Tupac Amaru 210, Lima (Peru)

2007-10-26

339

SURFACE LOOP RESONATOR DESIGN FOR IN VIVO EPR TOOTH DOSIMETRY USING FINITE ELEMENT ANALYSIS  

PubMed Central

Finite element analysis is used to evaluate and design L-band surface loop resonators for in vivo electron paramagnetic resonance (EPR) tooth dosimetry. This approach appears to be practical and useful for the systematic examination and evaluation of resonator configurations to enhance the precision of dose estimates. The effects of loop positioning in the mouth are examined, and it is shown that the sensitivity to loop position along a row of molars is decreased as the loop is moved away from the teeth.

Pollock, Jennifer D.; Williams, Benjamin B.; Sidabras, Jason W.; Grinberg, Oleg; Salikhov, Ildar; Lesniewski, Piotr; Kmiec, Maciej; Swartz, Harold M.

2014-01-01

340

Novel functional profiling approach combining reverse phase protein microarrays and human 3-D ex vivo tissue cultures: expression of apoptosis-related proteins in human colon cancer.  

PubMed

Cancer is caused by a complex pattern of molecular perturbations. To understand the biology of cancer, it is thus important to look at the activation state of key proteins and signaling networks. The limited amount of available sample material from patients and the complexity of protein expression patterns make the use of traditional protein analysis methods particularly difficult. In addition, the only approach that is currently available for performing functional studies is the use of serial biopsies, which is limited by ethical constraints and patient acceptance. The goal of this work was to establish a 3-D ex vivo culture technique in combination with reverse-phase protein microarrays (RPPM) as a novel experimental tool for use in cancer research. The RPPM platform allows the parallel profiling of large numbers of protein analytes to determine their relative abundance and activation level. Cancer tissue and the respective corresponding normal tissue controls from patients with colorectal cancer were cultured ex vivo. At various time points, the cultured samples were processed into lysates and analyzed on RPPM to assess the expression of carcinoembryonic antigen (CEA) and 24 proteins involved in the regulation of apoptosis. The methodology displayed good robustness and low system noise. As a proof of concept, CEA expression was significantly higher in tumor compared with normal tissue (p<0.0001). The caspase 9 expression signal was lower in tumor tissue than in normal tissue (p<0.001). Cleaved Caspase 8 (p=0.014), Bad (p=0.007), Bim (p=0.007), p73 (p=0.005), PARP (p<0.001), and cleaved PARP (p=0.007) were differentially expressed in normal liver and normal colon tissue. We demonstrate here the feasibility of using RPPM technology with 3-D ex vivo cultured samples. This approach is useful for investigating complex patterns of protein expression and modification over time. It should allow functional proteomics in patient samples with various applications such as pharmacodynamic analyses in drug development. PMID:19609961

Pirnia, Farzaneh; Pawlak, Michael; Thallinger, Gerhard G; Gierke, Berthold; Templin, Markus F; Kappeler, Andi; Betticher, Daniel C; Gloor, Beat; Borner, Markus M

2009-07-01

341

In vivo enhancer analysis of human conserved non-coding sequences.  

PubMed

Identifying the sequences that direct the spatial and temporal expression of genes and defining their function in vivo remains a significant challenge in the annotation of vertebrate genomes. One major obstacle is the lack of experimentally validated training sets. In this study, we made use of extreme evolutionary sequence conservation as a filter to identify putative gene regulatory elements, and characterized the in vivo enhancer activity of a large group of non-coding elements in the human genome that are conserved in human-pufferfish, Takifugu (Fugu) rubripes, or ultraconserved in human-mouse-rat. We tested 167 of these extremely conserved sequences in a transgenic mouse enhancer assay. Here we report that 45% of these sequences functioned reproducibly as tissue-specific enhancers of gene expression at embryonic day 11.5. While directing expression in a broad range of anatomical structures in the embryo, the majority of the 75 enhancers directed expression to various regions of the developing nervous system. We identified sequence signatures enriched in a subset of these elements that targeted forebrain expression, and used these features to rank all approximately 3,100 non-coding elements in the human genome that are conserved between human and Fugu. The testing of the top predictions in transgenic mice resulted in a threefold enrichment for sequences with forebrain enhancer activity. These data dramatically expand the catalogue of human gene enhancers that have been characterized in vivo, and illustrate the utility of such training sets for a variety of biological applications, including decoding the regulatory vocabulary of the human genome. PMID:17086198

Pennacchio, Len A; Ahituv, Nadav; Moses, Alan M; Prabhakar, Shyam; Nobrega, Marcelo A; Shoukry, Malak; Minovitsky, Simon; Dubchak, Inna; Holt, Amy; Lewis, Keith D; Plajzer-Frick, Ingrid; Akiyama, Jennifer; De Val, Sarah; Afzal, Veena; Black, Brian L; Couronne, Olivier; Eisen, Michael B; Visel, Axel; Rubin, Edward M

2006-11-23

342

Applying microscopy to the analysis of nuclear structure and function.  

PubMed

One of the ultimate goals of biological research is to understand mechanisms of cell function within living organisms. With this in mind, many sophisticated technologies that allow us to inspect macromolecular structure in exquisite detail have been developed. Although knowledge of structure derived from techniques such as X-ray crystallography and nuclear magnetic resonance is of vital importance, these approaches cannot reveal the remarkable complexity of molecular interactions that exists in vivo. With this in mind, this review focuses on the use of microscopy techniques to analyze cell structure and function. We describe the different basic microscopic methodologies and how the routine techniques are best applied to particular biological problems. We also emphasize the specific capabilities and uses of light and electron microscopy and highlight their individual advantages and disadvantages. For completion, we also comment on the alternative possibilities provided by a variety of advanced imaging technologies. We hope that this brief analysis of the undoubted power of microscopy techniques will be enough to stimulate a wider participation in this rapidly developing area of biological discovery. PMID:12606219

Iborra, Francisco; Cook, Peter R; Jackson, Dean A

2003-02-01

343

Endogenous Truncated TrkB.T1 Receptor Regulates Neuronal Complexity and TrkB Kinase Receptor Function in vivo  

PubMed Central

Pathological or in vitro over expression of the truncated TrkB.T1 receptor inhibits signaling through the full-length TrkB (TrkB.FL) tyrosine kinase receptor. However, to date, the role of endogenous TrkB.T1 is still unknown. By studying mice lacking the truncated TrkB.T1 isoform but retaining normal spatio-temporal expression of TrkB.FL we have analyzed TrkB.T1 specific physiological functions and its effect on endogenous TrkB kinase signaling in vivo. We found that TrkB.T1 deficient mice develop normally but show increased anxiety in association with morphological abnormalities in the length and complexity of neurites of neurons in the basolateral amygdala. However, no behavioral abnormalities were detected in hippocampal-dependent memory tasks, which correlated with lack of any obvious hippocampal morphological deficits or alterations in basal synaptic transmission and Long-Term Potentiation (LTP). In vivo reduction of TrkB signaling by removal of one BDNF allele could be partially rescued by TrkB.T1 deletion, which was revealed by an amelioration of the enhanced aggression and weight gain associated to BDNF haploinsufficiency. Our results suggest that at the physiological level, TrkB.T1 receptors are important regulators of TrkB.FL signaling in vivo. Moreover, TrkB.T1 selectively affects dendrite complexity of certain neuronal populations.

Carim-Todd, Laura; Bath, Kevin G.; Fulgenzi, Gianluca; Yanpallewar, Sudhirkumar; Jing, Deqiang; Barrick, Colleen A.; Becker, Jodi; Buckley, Hannah; Dorsey, Susan G.; Lee, Francis S.; Tessarollo, Lino

2009-01-01

344

In vivo assembly of functional U7 snRNP requires RNA backbone flexibility within the Sm-binding site.  

PubMed

Most histone precursor mRNAs (pre-mRNAs) in metazoans are matured by 3'-end cleavage directed by the U7 small nuclear ribonucleoprotein (snRNP). RNA functional groups necessary for in vivo assembly and activity of the U7 snRNP were examined by nucleotide-analog interference mapping and mutagenesis using a chimeric mouse histone H4 pre-mRNA-U7 snRNA construct that is cleaved in cis in Xenopus laevis oocytes. Assembly of the unique U7 Sm protein core is rate limiting for processing in vivo and requires four conserved nucleotides within the U7 Sm-binding site, as well as the correct positioning and size of the U7 terminal stem-loop structure. To our surprise, pseudouridine substitution revealed a requirement for backbone flexibility at a particular position within the U7 Sm site, providing in vivo biochemical evidence that an unusual C2'-endo sugar conformation is necessary for assembly of the Sm ring. PMID:16547514

Kolev, Nikolay G; Steitz, Joan A

2006-04-01

345

In Vivo Confocal Microscopy of Corneal Nerves: Analysis and Clinical Correlation  

PubMed Central

Corneal confocal microscopy is a growing technique for the study of the cornea at the cellular level, providing images comparable to ex vivo histochemical methods. In vivo confocal microscopy (IVCM) has an enormous potential, being a noninvasive procedure that images the living cornea, to study both its physiological and pathological states. Corneal nerves are of great interest to clinicians and scientists due to their important roles in regulating corneal sensation, epithelial integrity, proliferation, wound healing, and for their protective functions. IVCM enables the noninvasive examination of corneal nerves, allowing the study of nerve alterations in different ocular diseases, after corneal surgery, and in systemic diseases. To date, the correlation of sub-basal corneal nerves and their function has been studied in normal eyes, keratoconus, dry eye, contact lens wearers, and in neurotrophic keratopathy, among others. Further, the effect of corneal surgery on nerves has been studied, demonstrating the regenerative capacity of corneal nerves and the recovery of sensation. Moreover, IVCM has been applied in the diagnosis of peripheral diabetic neuropathy and the assessment of progression in this systemic disease. The purpose of this review is to describe the principles, applications, and clinical correlation of IVCM in the study of corneal nerves in different ocular and systemic diseases.

Cruzat, Andrea; Pavan-Langston, Deborah; Hamrah, Pedram

2011-01-01

346

Pseudophosphatases: methods of analysis and physiological functions.  

PubMed

Protein tyrosine phosphatases (PTPs) are key enzymes in the regulation of cellular homeostasis and signaling pathways. Strikingly, not all PTPs bear enzymatic activity. A considerable fraction of PTPs are enzymatically inactive and are known as pseudophosphatases. Despite the lack of activity they execute pivotal roles in development, cell biology and human disease. The present review is focused on the methods used to identify pseudophosphatases, their targets, and physiological roles. We present a strategy for detailed enzymatic analysis of inactive PTPs, regulation of inactive PTP domains and identification of binding partners. Furthermore, we provide a detailed overview of human pseudophosphatases and discuss their regulation of cellular processes and functions in human pathologies. PMID:24064037

Kharitidi, Dmitri; Manteghi, Sanaz; Pause, Arnim

2014-01-15

347

Functional diversity for REST (NRSF) is defined by in vivo binding affinity hierarchies at the DNA sequence level  

PubMed Central

The molecular events that contribute to, and result from, the in vivo binding of transcription factors to their cognate DNA sequence motifs in mammalian genomes are poorly understood. We demonstrate that variations within the DNA sequence motifs that bind the transcriptional repressor REST (NRSF) encode in vivo DNA binding affinity hierarchies that contribute to regulatory function during lineage-specific and developmental programs in fundamental ways. First, canonical sequence motifs for REST facilitate strong REST binding and control functional classes of REST targets that are common to all cell types, whilst atypical motifs participate in weak interactions and control those targets, which are cell- or tissue-specific. Second, variations in REST binding relate directly to variations in expression and chromatin configurations of REST's target genes. Third, REST clearance from its binding sites is also associated with variations in the RE1 motif. Finally, and most surprisingly, weak REST binding sites reside in DNA sequences that show the highest levels of constraint through evolution, thus facilitating their roles in maintaining tissue-specific functions. These relationships have never been reported in mammalian systems for any transcription factor.

Bruce, Alexander W.; Lopez-Contreras, Andres J.; Flicek, Paul; Down, Thomas A.; Dhami, Pawandeep; Dillon, Shane C.; Koch, Christoph M.; Langford, Cordelia F.; Dunham, Ian; Andrews, Robert M.; Vetrie, David

2009-01-01

348

Reversion analysis of dynein intermediate chain function.  

PubMed

The ODA6 locus of Chlamydomonas reinhardtii encodes a 70 kDa intermediate chain protein of the flagellar outer row dynein ATPase, and mutations at this locus prevent assembly of the entire outer row dynein arm complex. To initiate a structure-function analysis of the 70 kDa protein, we used transformation with chimeric mutant/wild-type genes to localize the defect in one assembly mutation, oda6-95. Sequence analysis revealed a frame-shift mutation in codon 53, which is followed by a stop codon after 13 amino acids in the new reading frame. By selecting intragenic pseudorevertants of this mutation we obtained 11 new oda6 alleles. Many of these pseudorevertants encode intermediate chain proteins that permit assembly of outer row arms but do not restore full wild-type motility. Revertant strains fall into two phenotypic classes, one with average beat frequencies of 54 Hz (similar to wild type) and one with average frequencies of 27 Hz (compared with 24 Hz for oda6-95) during normal forward swimming. Low beat frequency strains also display abnormalities during photophobic reversal (symmetric waveform). Amplification and sequence analysis of revertant alleles indicated that each reversion caused a second frame-shift, within a 115 nt interval, which restored the original reading frame, and that phenotypic severity was related to both direction (5' or 3') and distance between the original mutation and the reversion event. On the basis of immunoblot analysis of outer arm proteins, we conclude that revertant motility defects do not correlate with deficits in assembly of a specific dynein heavy chain or intermediate chain polypeptide, and electron microscopy confirms that revertants have normal outer arm structures. These results suggest that the 70 kDa intermediate chain plays a direct role in outer arm function distinct from its role in the assembly process. PMID:8227195

Mitchell, D R; Kang, Y

1993-08-01

349

Functional Analysis of the Aspergillus nidulans Kinome  

PubMed Central

The filamentous fungi are an ecologically important group of organisms which also have important industrial applications but devastating effects as pathogens and agents of food spoilage. Protein kinases have been implicated in the regulation of virtually all biological processes but how they regulate filamentous fungal specific processes is not understood. The filamentous fungus Aspergillus nidulans has long been utilized as a powerful molecular genetic system and recent technical advances have made systematic approaches to study large gene sets possible. To enhance A. nidulans functional genomics we have created gene deletion constructs for 9851 genes representing 93.3% of the encoding genome. To illustrate the utility of these constructs, and advance the understanding of fungal kinases, we have systematically generated deletion strains for 128 A. nidulans kinases including expanded groups of 15 histidine kinases, 7 SRPK (serine-arginine protein kinases) kinases and an interesting group of 11 filamentous fungal specific kinases. We defined the terminal phenotype of 23 of the 25 essential kinases by heterokaryon rescue and identified phenotypes for 43 of the 103 non-essential kinases. Uncovered phenotypes ranged from almost no growth for a small number of essential kinases implicated in processes such as ribosomal biosynthesis, to conditional defects in response to cellular stresses. The data provide experimental evidence that previously uncharacterized kinases function in the septation initiation network, the cell wall integrity and the morphogenesis Orb6 kinase signaling pathways, as well as in pathways regulating vesicular trafficking, sexual development and secondary metabolism. Finally, we identify ChkC as a third effector kinase functioning in the cellular response to genotoxic stress. The identification of many previously unknown functions for kinases through the functional analysis of the A. nidulans kinome illustrates the utility of the A. nidulans gene deletion constructs.

De Souza, Colin P.; Hashmi, Shahr B.; Osmani, Aysha H.; Andrews, Peter; Ringelberg, Carol S.; Dunlap, Jay C.; Osmani, Stephen A.

2013-01-01

350

Transparent adult zebrafish as a tool for in vivo transplantation analysis  

PubMed Central

The zebrafish is a useful model for understanding normal and cancer stem cells, but analysis has been limited to embryogenesis due to the opacity of the adult fish. To address this, we have created a transparent adult zebrafish in which we transplanted either hematopoietic stem/progenitor cells or tumor cells. In a hematopoiesis radiation recovery assay, transplantation of GFP-labeled marrow cells allowed for striking in vivo visual assessment of engraftment from 2 hours-5 weeks post transplant. Using FACS analysis, both transparent and wild-type fish had equal engraftment, but this could only be visualized in the transparent recipient. In a tumor engraftment model, transplantation of RAS-melanoma cells allowed for visualization of tumor engraftment, proliferation and distant metastases in as little as 5 days, which is not seen in wild-type recipients until 3-4 weeks. This transparent adult zebrafish serves as the ideal combination of both sensitivity and resolution for in vivo stem cell analyses.

White, Richard Mark; Sessa, Anna; Burke, Christopher; Bowman, Teresa; LeBlanc, Jocelyn; Ceol, Craig; Bourque, Caitlin; Dovey, Michael; Goessling, Wolfram; Burns, Caroline Erter; Zon, Leonard I.

2008-01-01

351

In vivo and in vitro analysis of topographic changes secondary to DSAEK venting incisions  

PubMed Central

Introduction Descemet’s stripping automated endothelial keratoplasty (DSAEK) venting incisions may induce irregular corneal astigmatism. The study examines in vivo and in vitro astigmatic effects of venting incisions. Patients and methods In vivo analysis examined eleven eyes of eleven patients who had received DSAEK with venting incisions. A chart review of the eleven eyes including assessment of pre and postoperative refraction and topography was performed. In vitro analysis examined three cadaver eyes which received topographic imaging followed by venting incisions at 4 mm, 6 mm, and 7 mm optical zones. Topographic imaging was then performed again after the incisions. Results Postoperative topographies of eleven eyes demonstrated localized flattening at incision sites and cloverleaf pattern astigmatism. There was a significant difference in corneal irregularity measurement (P = 0.03), but no significant difference in shape factor or change of topographic cylinder. The cloverleaf pattern was found in cadaver eyes with incisions placed at 4 mm and 6 mm optical zones but not at the 7 mm zone. Conclusion DSAEK venting incisions can cause irregular corneal astigmatism that may affect visual outcomes. The authors recommend placement of venting incisions near the 7 mm optical zone.

Moshirfar, Majid; Lependu, Monette T; Church, Dane; Neuffer, Marcus C

2011-01-01

352

Toward dynamic isotopomer analysis in the rat brainin vivo: automatic quantitation of13C NMR spectra using LCModel  

Microsoft Academic Search

The LCModel method was adapted to analyze localized in vivo 13C NMR spectra obtained from the rat brain invivo at 9.4 T. Prior knowledge of chemical-shifts, J-coupling constants and J-evolution was included in the analysis. Up to 50 different isotopomer signals corresponding to 10 metabolites were quantified simultaneously in 400ml volumes in the rat brain in vivo during infusion of

Pierre-Gilles Henry; Gülin Öz; Stephen Provencher; Rolf Gruetter

2003-01-01

353

Probing cell type-specific functions of Gi in vivo identifies GPCR regulators of insulin secretion.  

PubMed

The in vivo roles of the hundreds of mammalian G protein-coupled receptors (GPCRs) are incompletely understood. To explore these roles, we generated mice expressing the S1 subunit of pertussis toxin, a known inhibitor of G(i/o) signaling, under the control of the ROSA26 locus in a Cre recombinase-dependent manner (ROSA26(PTX)). Crossing ROSA26(PTX) mice to mice expressing Cre in pancreatic beta cells produced offspring with constitutive hyperinsulinemia, increased insulin secretion in response to glucose, and resistance to diet-induced hyperglycemia. This phenotype underscored the known importance of G(i/o) and hence of GPCRs for regulating insulin secretion. Accordingly, we quantified mRNA for each of the approximately 373 nonodorant GPCRs in mouse to identify receptors highly expressed in islets and examined the role of several. We report that 3-iodothyronamine, a thyroid hormone metabolite, could negatively and positively regulate insulin secretion via the G(i)-coupled alpha(2A)-adrenergic receptor and the G(s)-coupled receptor Taar1, respectively, and protease-activated receptor-2 could negatively regulate insulin secretion and may contribute to physiological regulation of glucose metabolism. The ROSA26(PTX) system used in this study represents a new genetic tool to achieve tissue-specific signaling pathway modulation in vivo that can be applied to investigate the role of G(i/o)-coupled GPCRs in multiple cell types and processes. PMID:17992256

Regard, Jean B; Kataoka, Hiroshi; Cano, David A; Camerer, Eric; Yin, Liya; Zheng, Yao-Wu; Scanlan, Thomas S; Hebrok, Matthias; Coughlin, Shaun R

2007-12-01

354

Probing cell type-specific functions of Gi in vivo identifies GPCR regulators of insulin secretion  

PubMed Central

The in vivo roles of the hundreds of mammalian G protein–coupled receptors (GPCRs) are incompletely understood. To explore these roles, we generated mice expressing the S1 subunit of pertussis toxin, a known inhibitor of Gi/o signaling, under the control of the ROSA26 locus in a Cre recombinase–dependent manner (ROSA26PTX). Crossing ROSA26PTX mice to mice expressing Cre in pancreatic ? cells produced offspring with constitutive hyperinsulinemia, increased insulin secretion in response to glucose, and resistance to diet-induced hyperglycemia. This phenotype underscored the known importance of Gi/o and hence of GPCRs for regulating insulin secretion. Accordingly, we quantified mRNA for each of the approximately 373 nonodorant GPCRs in mouse to identify receptors highly expressed in islets and examined the role of several. We report that 3-iodothyronamine, a thyroid hormone metabolite, could negatively and positively regulate insulin secretion via the Gi-coupled ?2A-adrenergic receptor and the Gs-coupled receptor Taar1, respectively, and protease-activated receptor–2 could negatively regulate insulin secretion and may contribute to physiological regulation of glucose metabolism. The ROSA26PTX system used in this study represents a new genetic tool to achieve tissue-specific signaling pathway modulation in vivo that can be applied to investigate the role of Gi/o-coupled GPCRs in multiple cell types and processes.

Regard, Jean B.; Kataoka, Hiroshi; Cano, David A.; Camerer, Eric; Yin, Liya; Zheng, Yao-Wu; Scanlan, Thomas S.; Hebrok, Matthias; Coughlin, Shaun R.

2007-01-01

355

ABCG2 functions as a general phytoestrogen sulfate transporter in vivo.  

PubMed

ABCG2 is an ATP-dependent efflux transporter that limits the systemic exposure of its substrates. The preferred substrates of ABCG2 in vivo are largely unknown. We aimed to identify the compounds transported by ABCG2 under physiological conditions. In vitro, ABCG2 transports several sulfate conjugates at high rates. We therefore used targeted metabolomics, specifically detecting compounds conjugated to sulfate, to search in plasma, urine, and bile samples of wild-type and Abcg2-/- mice for differentially present compounds, which are likely to represent in vivo ABCG2 substrates. Levels of many sulfate conjugates were up to 15-fold higher in plasma and urine of Abcg2-/- than of wild-type mice, with the opposite effect seen in bile. These differentially present compounds were identified as the sulfate conjugates of phytoestrogens, compounds with weak pro- or antiestrogenic properties. We confirmed that these sulfate conjugates were ABCG2 substrates using transportomics, a method that uses vesicular transport assays to screen for substrates of ABC transporters in body fluids. In conclusion, our results show that ABCG2 limits the systemic exposure to many different phytoestrogens, a class of compounds to which mammals are exposed on a daily basis via food of plant origin, by directing their sulfate conjugates for excretion via the feces. PMID:22707564

van de Wetering, Koen; Sapthu, Sunny

2012-10-01

356

Epigenetic modulation of human breast cancer by metallofullerenol nanoparticles: in vivo treatment and in vitro analysis  

NASA Astrophysics Data System (ADS)

Multi-hydroxylated endohedral metallofullerenol [Gd@C82(OH)22]n nanoparticles possess the general physico-chemical characteristics of most nanoparticles. They also exhibit uniquely low toxicity and antineoplastic efficacy. In the current study, the molecular mechanisms and epigenetic characteristics of the antineoplastic action of these nanoparticles are explored. Human breast cancer MCF-7 and human umbilical vein endothelial ECV304 cell lines were used. Cell viability assay, cell hierarchical cluster analysis by cDNA microarray, semi-quantitative reverse transcription-polymerase chain reaction and Western blot analysis were conducted to investigate the changes in molecular and cellular signaling pathways caused by [Gd@C82(OH)22]n. The results demonstrated the high antitumor activity and low cytotoxicity of [Gd@C82(OH)22]n nanoparticles both in vivo and in vitro. Their possible anti-tumor mechanisms were also discussed. The present study may provide new insight into the mechanism of action of these nanoparticles.

Meng, Jie; Xing, Jianmin; Wang, Yingze; Lu, Juan; Zhao, Yuliang; Gao, Xueyun; Wang, Paul C.; Jia, Lee; Liang, Xingjie

2011-11-01

357

Transfer function analysis of thermospheric perturbations  

NASA Astrophysics Data System (ADS)

Applying perturbation theory, a spectral model in terms of vectors spherical harmonics (Legendre polynomials) is used to describe the short term thermospheric perturbations originating in the auroral regions. The source may be Joule heating, particle precipitation or ExB ion drift-momentum coupling. A multiconstituent atmosphere is considered, allowing for the collisional momentum exchange between species including Ar, O2, N2, O, He and H. The coupled equations of energy, mass and momentum conservation are solved simultaneously for the major species N2 and O. Applying homogeneous boundary conditions, the integration is carred out from the Earth's surface up to 700 km. In the analysis, the spherical harmonics are treated as eigenfunctions, assuming that the Earth's rotation (and prevailing circulation) do not significantly affect perturbations with periods which are typically much less than one day. Under these simplifying assumptions, and given a particular source distribution in the vertical, a two dimensional transfer function is constructed to describe the three dimensional response of the atmosphere. In the order of increasing horizontal wave numbers (order of polynomials), this transfer function reveals five components. To compile the transfer function, the numerical computations are very time consuming (about 100 hours on a VAX for one particular vertical source distribution). However, given the transfer function, the atmospheric response in space and time (using Fourier integral representation) can be constructed with a few seconds of a central processing unit. This model is applied in a case study of wind and temperature measurements on the Dynamics Explorer B, which show features characteristic of a ringlike excitation source in the auroral oval. The data can be interpreted as gravity waves which are focused (and amplified) in the polar region and then are reflected to propagate toward lower latitudes.

Mayr, H. G.; Harris, I.; Varosi, F.; Herrero, F. A.; Spencer, N. W.

1986-06-01

358

In vivo evidence for a functional role of both tumor necrosis factor (TNF) receptors and transmembrane TNF in experimental hepatitis.  

PubMed

The significance of tumor necrosis factor receptor 1 (TNFR1) for TNF function in vivo is well documented, whereas the role of TNFR2 so far remains obscure. In a model of concanavalin A (Con A)-induced, CD4+ T cell-dependent experimental hepatitis in mice, in which TNF is a central mediator of apoptotic and necrotic liver damage, we now provide evidence for an essential in vivo function of TNFR2 in this pathophysiological process. We demonstrate that a cooperation of TNFR1 and TNFR2 is required for hepatotoxicity as mice deficient of either receptor were resistant against Con A. A significant role of TNFR2 for Con A-induced hepatitis is also shown by the enhanced sensitivity of transgenic mice overexpressing the human TNFR2. The ligand for cytotoxic signaling via both TNF receptors is the precursor of soluble TNF, i.e. transmembrane TNF. Indeed, transmembrane TNF is sufficient to mediate hepatic damage, as transgenic mice deficient in wild-type soluble TNF but expressing a mutated nonsecretable form of TNF developed inflammatory liver disease. PMID:9394812

Küsters, S; Tiegs, G; Alexopoulou, L; Pasparakis, M; Douni, E; Künstle, G; Bluethmann, H; Wendel, A; Pfizenmaier, K; Kollias, G; Grell, M

1997-11-01

359

Regulatory functions of self-restricted MHC class II allopeptide-specific Th2 clones in vivo  

PubMed Central

We studied T-cell clones generated from grafts of rejecting and tolerant animals and investigated the regulatory function of Th2 clones in vitro and in vivo. To prevent allograft rejection, we treated LEW strain recipient rats of WF strain kidney grafts with CTLA4Ig to block CD28-B7 costimulation. We then isolated epitope-specific T-cell clones from the engrafted tissue, using a donor-derived immunodominant class II MHC allopeptide presented by recipient antigen-presenting cells. Acutely rejected tissue from untreated animals yielded self-restricted, allopeptide-specific T-cell clones that produced IFN-?, whereas clones from tolerant animals produced IL-4 and IL-10. Adoptive transfer into naive recipients of Th1 clones, but not Th2 clones, induced alloantigen-specific delayed-type hypersensitivity (DTH) responses. In addition, Th2 clones suppressed DTH responses mediated by Th1 clones in vivo and blocked Th1 cell proliferation and IFN-? production in vitro. A pilot human study showed that HLA-DR allopeptide-specific T-cell clones generated from patients with chronic rejection secrete Th1 cytokines, whereas those from patients with stable graft function produce Th2 cytokines in response to donor-specific HLA-DR allopeptides. We suggest that self-restricted alloantigen-specific Th2 clones may regulate the alloimmune responses and promote long-term allograft survival and tolerance.

Waaga, Ana Maria; Gasser, Martin; Kist-van Holthe, Joana E.; Najafian, Nader; Muller, Angelika; Vella, John P.; Womer, Karl L.; Chandraker, Anil; Khoury, Samia J.; Sayegh, Mohamed H.

2001-01-01

360

Regulation of memory CD4 T-cell pool size and function by natural killer T cells in vivo  

PubMed Central

To develop more effective vaccines and strategies to regulate chronic inflammatory diseases, it is important to understand the mechanisms of immunological memory. Factors regulating memory CD4+ T helper (Th)-cell pool size and function remain unclear, however. We show that activation of type I invariant natural killer T (iNKT) cells with glycolipid ligands and activation of type II natural killer T (NKT) cells with the endogenous ligand sulfatide induced dramatic proliferation and expansion of memory, but not naïve, CD4 T cells. NKT cell-induced proliferation of memory Th1 and Th2 cells was dependent largely on the production of IL-2, with Th2-cell proliferation also affected by loss of IL-4. Type II NKT cells were also required for efficient maintenance of memory CD4 T cells in vivo. Activation of iNKT cells resulted in up-regulation of IFN-? expression by memory Th2 cells. These IFN-?–producing memory Th2 cells showed a decreased capability to induce Th2 cytokines and eosinophilic airway inflammation. Thus, activated NKT cells directly regulate memory CD4 T-cell pool size and function via the production of cytokines in vivo.

Iwamura, Chiaki; Shinoda, Kenta; Endo, Yusuke; Watanabe, Yukiko; Tumes, Damon John; Motohashi, Shinichiro; Kawahara, Kazuyoshi; Kinjo, Yuki; Nakayama, Toshinori

2012-01-01

361

Goserelin can inhibit ovarian cancer proliferation and simultaneously protect ovarian function from cisplatin: an in vitro and in vivo study.  

PubMed

This study investigates whether goserelin can inhibit ovarian cancer proliferation and protect ovarian function from cisplatin (CDDP). We evaluated proliferation and AKT phosphorylation in goserelin-treated ES-2 and SKOV3-ip ovarian cancer cells. Anti-Müllerian hormone (AMH) in human granulosa cells (hGCs) cotreated with goserelin and CDDP was measured by ELISA. Tumour volumes, Ki-67 expression, estrus, follicles, ovarian volumes, and serum AMH were compared in nude mice bearing transplanted tumours treated with goserelin and/or CDDP. Our results showed that goserelin inhibited cellular proliferation and AKT phosphorylation in vitro, and inhibited tumour growth and Ki-67 expression in vivo. Goserelin and CDDP cotreatment decreased the estrus cycles of the nude mice and prolonged estrus duration. Goserelin abrogated the CDDP-induced down-regulation of primary and preantral follicle percentage and ovarian volume. Goserelin increased AMH secretion in vitro and in vivo. In conclusion, goserelin inhibited ovarian cancer proliferation and simultaneously protected ovarian function from CDDP. PMID:23684357

Zhang, Ying; Ding, Jing Xin; Tao, Xiang; Lu, Zhi Ying; Wang, Jia Jia; Feng, Wei Wei; Hua, Ke Qin

2013-04-01

362

Validation protocol for assessing the upper cervical spine kinematics and helical axis: An in vivo preliminary analysis for axial rotation, modeling, and motion representation  

PubMed Central

Context: The function of the upper cervical spine (UCS) is essential in the kinematics of the whole cervical spine. Specific motion patterns are described at the UCS during head motions to compensate coupled motions occurring at the lower cervical segments. Aims: First, two methods for computing in vitro UCS discrete motions were compared to assess three-dimensional (3D) kinematics. Secondly, the same protocol was applied to assess the feasibility of the procedure for in vivo settings. Also, this study attempts to expose the use of anatomical modeling for motion representation including helical axis. Settings and Design: UCS motions were assessed to verify the validity of in vitro 3D kinematics and to present an in vivo procedure for evaluating axial rotation. Materials and Methods: In vitro kinematics was sampled using a digitizing technique and computed tomography (CT) for assessing 3D motions during flexion extension and axial rotation. To evaluate the feasibility of this protocol in vivo, one asymptomatic volunteer performed an MRI kinematics evaluation of the UCS for axial rotation. Data processing allowed integrating data into UCS 3D models for motion representation, discrete joint behavior, and motion helical axis determination. Results: Good agreement was observed between the methods with angular displacement differences ranging from 1° to 1.5°. Helical axis data were comparable between both methods with axis orientation differences ranging from 3° to 6°. In vivo assessment of axial rotation showed coherent kinematics data compared to previous studies. Helical axis data were found to be similar between in vitro and in vivo evaluation. Conclusions: The present protocol confirms agreement of methods and exposes its feasibility to investigate in vivo UCS kinematics. Moreover, combining motion analysis, helical axis representation, and anatomical modeling, constitutes an innovative development to provide new insights for understanding motion behaviors of the UCS.

Dugailly, Pierre-Michel; Sobczak, Stephane; Lubansu, Alphonse; Rooze, Marcel; Jan, SergeVan Sint; Feipel, Veronique

2013-01-01

363

Pharmacokinetic analysis of free radicals by in vivo BCM (Blood Circulation Monitoring)-ESR method.  

PubMed

In pharmacokinetic studies, a variety of analytical method including radioisotopic detection and HPLC (high performance liquid chromatography) has been used. In the present investigation, we developed in vivo BCM (Blood Circulation Monitoring)-ESR method, which is a new technique with a conventional X-band ESR spectrometer for observing stable free radicals in the circulating blood of living rats under anaesthesia. Both 5-(PROXYL derivatives) and 6-(TEMPO d derivatives) membered nitroxide spin probes with various types of substituent functional group were used. After physico-chemical properties of the spin probes such as hyperfine coupling constant (A-value), g-value and partition coefficient as well as chemical stability of the compounds in the fresh blood were obtained, the in vivo BCM-ESR method was performed in normal rats. Several pharmacokinetic parameters such as half-life of the probes, distribution volume, total body clearance and mean residence time were obtained and discussed in terms of their chemical structures. In addition, clearance of a spin probe was related to the urine concentration. The BCM-ESR method was found to be very useful to observe free radicals at the real time. By time-dependent ESR signal decay of spin probes, pharmacokinetic parameters were obtained. PMID:9212342

Takechi, K; Tamura, H; Yamaoka, K; Sakurai, H

1997-06-01

364

In vivo biological responses to silk proteins functionalized with bone sialoprotein.  

PubMed

Recombinant 6mer?+?BSP protein, combining six repeats of the consensus sequence for Nephila clavipes dragline (6mer) and bone sialoprotein sequence (BSP), shows good support for cell viability and induces the nucleation of hydroxyapatite and tricalcium phosphate during osteoblast in vitro culture. The present study is conducted to characterize this bioengineered protein-based biomaterial further for in vivo behavior related to biocompatibility. 6mer?+?BSP protein films are implanted in subcutaneous pouches in the back of mice and responses are evaluated by flow cytometry and histology. The results show no major differences between the inflammatory responses induced by 6mer?+?BSP films and the responses observed for the controls. Thus, this new chimeric protein could represent an alternative for bone regeneration applications. PMID:23359587

Gomes, Sílvia; Gallego-Llamas, Jabier; Leonor, Isabel B; Mano, João F; Reis, Rui L; Kaplan, David L

2013-04-01

365

Preferential accumulation within tumors and in vivo imaging by functionalized luminescent dendrimer lanthanide complexes  

PubMed Central

We have created a dendrimer complex suitable for preferential accumulation within liver tumors and luminescence imaging by substituting thirty-two naphthalimide fluorophores on the surface of the dendrimer and incorporating eight europium cations within the branches. We demonstrate the utility and performance of this luminescent dendrimer complex to detect hepatic tumors generated via direct subcapsular implantation or via splenic injections of colorectal cancer cells (CC531) into WAG/RijHsd rats. Luminescence imaging of the tumors after injection of the dendrimer complex via hepatic arterial infusion revealed that the dendrimer complex can preferentially accumulate within liver tumors. Further investigation indicated that dendrimer luminescence in hepatic tumors persisted in vivo. Due to the incorporation of lanthanide cations, this luminescence agent presents a strong resistance against photobleaching. These studies show the dendrimer complex has great potential to serve as an innovative accumulation and imaging agent for the detection of metastatic tumors in our rat hepatic model.

Alcala, Marco A.; Shade, Chad M.; Uh, Hyounsoo; Kwan, Shu Ying; Bischof, Matthias; Thompson, Zachary P.; Gogick, Kristy A.; Meier, Adam R.; Strein, Timothy G.; Bartlett, David L.; Modzelewski, Ruth A.; Lee, Yong J.; Petoud, Stephane; Brown, Charles Komen

2011-01-01

366

Mammalian mitochondrial DNA sequences can function as in vivo bacterial transcription terminators.  

PubMed

We have used a prokaryotic terminator identification vector, pDR721, to isolate regions from rat mitochondrial DNA (mtDNA) that can act as transcription terminators in vivo. Three independent fragments having terminator capability have been mapped to three general regions of the mitochondrial genome. Two terminators, pRMT1 and pRMT3, are found within and around the D-loop and cytochrome b gene, respectively, while the third, pRMT5, is located at the 3'-end of the 16S ribosomal RNA gene. After subcloning into host cells which carried temperature sensitive mutations in the termination factor, rho protein, galactokinase assays at the permissive and non-permissive temperatures suggested that pRMT3 acted as a rho-independent termination element while the other two, pRMT1 and pRMT5, were dependent on rho protein (or a rho-like protein) for efficient transcription termination. PMID:8484772

Staub, J M; Castora, F J

1993-04-30

367

Analysis of body calcium (regional changes in body calcium by in vivo neutron activation analysis)  

NASA Technical Reports Server (NTRS)

The effect of space flight on urine and fecal calcium loss was documented during the three long-term Skylab flights. Neutron activation analysis was used to determine regional calcium loss. Various designs for regional analysis were investigated.

Suki, W.; Johnson, P. C.; Leblanc, A.; Evans, H. J.

1981-01-01

368

In vivo olfactory model of APP-induced neurodegeneration reveals a reversible cell-autonomous function.  

PubMed

Amyloid precursor protein (APP) has long been linked to the neurodegeneration of Alzheimer's disease (AD), but the associated cell death has been difficult to capture in vivo, and the role of APP in effecting neuron loss is still unclear. Olfactory dysfunction is an early symptom of AD with amyloid pathology in the olfactory epithelium correlating well to the brain pathology of AD patients. As olfactory sensory neurons (OSNs) regenerate continuously with immature and mature OSNs coexisting in the same olfactory epithelium, we sought to use this unique system to study APP-induced neurodegeneration. Here we have developed an olfactory-based transgenic mouse model that overexpresses humanized APP containing familial AD mutations (hAPP) in either mature or immature OSNs, and found that despite the absence of extracellular plaques a striking number of apoptotic neurons were detected by 3 weeks of age. Importantly, apoptosis was restricted to the specific population overexpressing hAPP, either mature or immature OSNs, sparing those without hAPP. Interestingly, we observed that this widespread neurodegeneration could be rapidly rescued by reducing hAPP expression levels in immature neurons. Together, these data argue that overexpressing hAPP alone could induce cell-autonomous apoptosis in both mature and immature neurons, challenging the notion that amyloid plaques are necessary for neurodegeneration. Furthermore, we show that hAPP-induced neurodegeneration is reversible, suggesting that AD-related neural loss could potentially be rescued. Thus, we propose that this unique in vivo model will not only help determine the mechanisms underlying AD-related neurodegeneration but also serve as a platform to test possible treatments. PMID:21957232

Cheng, Ning; Cai, Huaibin; Belluscio, Leonardo

2011-09-28

369

Ageing alters perivascular nerve function of mouse mesenteric arteries in vivo.  

PubMed

Abstract? Mesenteric arteries (MAs) are studied widely in vitro but little is known of their reactivity in vivo. Transgenic animals have enabled Ca(2+) signalling to be studied in isolated MAs but the reactivity of these vessels in vivo is undefined. We tested the hypothesis that ageing alters MA reactivity to perivascular nerve stimulation (PNS) and adrenoreceptor (AR) activation during blood flow control. First- (1A), second- (2A) and third-order (3A) MAs of pentobarbital-anaesthetized Young (3-6 months) and Old (24-26 months) male and female Cx40(BAC)-GCaMP2 transgenic mice (C57BL/6 background; positive or negative for the GCaMP2 transgene) were studied with intravital microscopy. A segment of jejunum was exteriorized and an MA network was superfused with physiological salt solution (pH 7.4, 37°C). Resting tone was 10% in MAs of Young and Old mice; diameters were ?5% (1A), 20% (2A) and 40% (3A) smaller (P 0.05) in Old mice. Throughout MA networks, vasoconstriction increased with PNS frequency (1-16 Hz) but was ?20% less in Young vs. Old mice (P 0.05) and was inhibited by tetrodotoxin (1 ?m). Capsaicin (10 ?m; to inhibit sensory nerves) enhanced MA constriction to PNS (P 0.05) by ?20% in Young but not Old mice. Phenylephrine (an ?1AR agonist) potency was greater in Young mice (P 0.05) with similar efficacy (?60% constriction) across ages and MA branches. Constrictions to UK14304 (an ?2AR agonist) were less (?20%; P 0.05) and were unaffected by ageing. Irrespective of sex or transgene expression, ageing consistently reduced the sensitivity of MAs to ?1AR vasoconstriction while blunting the attenuation of sympathetic vasoconstriction by sensory nerves. These findings imply substantive alterations in splanchnic blood flow control with ageing. PMID:23247111

Westcott, Erika B; Segal, Steven S

2013-03-01

370

Ageing alters perivascular nerve function of mouse mesenteric arteries in vivo  

PubMed Central

Mesenteric arteries (MAs) are studied widely in vitro but little is known of their reactivity in vivo. Transgenic animals have enabled Ca2+ signalling to be studied in isolated MAs but the reactivity of these vessels in vivo is undefined. We tested the hypothesis that ageing alters MA reactivity to perivascular nerve stimulation (PNS) and adrenoreceptor (AR) activation during blood flow control. First- (1A), second- (2A) and third-order (3A) MAs of pentobarbital-anaesthetized Young (3–6 months) and Old (24–26 months) male and female Cx40BAC-GCaMP2 transgenic mice (C57BL/6 background; positive or negative for the GCaMP2 transgene) were studied with intravital microscopy. A segment of jejunum was exteriorized and an MA network was superfused with physiological salt solution (pH 7.4, 37°C). Resting tone was ? 10% in MAs of Young and Old mice; diameters were ?5% (1A), 20% (2A) and 40% (3A) smaller (P? 0.05) in Old mice. Throughout MA networks, vasoconstriction increased with PNS frequency (1–16 Hz) but was ?20% less in Young vs. Old mice (P? 0.05) and was inhibited by tetrodotoxin (1 ?m). Capsaicin (10 ?m; to inhibit sensory nerves) enhanced MA constriction to PNS (P? 0.05) by ?20% in Young but not Old mice. Phenylephrine (an ?1AR agonist) potency was greater in Young mice (P? 0.05) with similar efficacy (?60% constriction) across ages and MA branches. Constrictions to UK14304 (an ?2AR agonist) were less (?20%; P? 0.05) and were unaffected by ageing. Irrespective of sex or transgene expression, ageing consistently reduced the sensitivity of MAs to ?1AR vasoconstriction while blunting the attenuation of sympathetic vasoconstriction by sensory nerves. These findings imply substantive alterations in splanchnic blood flow control with ageing.

Westcott, Erika B; Segal, Steven S

2013-01-01

371

In vivo analysis of highly conserved Nef activities in HIV-1 replication and pathogenesis  

PubMed Central

Background The HIV-1 accessory protein, Nef, is decisive for progression to AIDS. In vitro characterization of the protein has described many Nef activities of unknown in vivo significance including CD4 downregulation and a number of activities that depend on Nef interacting with host SH3 domain proteins. Here, we use the BLT humanized mouse model of HIV-1 infection to assess their impact on viral replication and pathogenesis and the selection pressure to restore these activities using enforced in vivo evolution. Results We followed the evolution of HIV-1LAI (LAI) with a frame-shifted nef (LAINeffs) during infection of BLT mice. LAINeffs was rapidly replaced in blood by virus with short deletions in nef that restored the open reading frame (LAINeffs?-1 and LAINeffs?-13). Subsequently, LAINeffs?-1 was often replaced by wild type LAI. Unexpectedly, LAINeffs?-1 and LAINeffs?-13 Nefs were specifically defective for CD4 downregulation activity. Viruses with these mutant nefs were used to infect BLT mice. LAINeffs?-1 and LAINeffs?-13 exhibited three-fold reduced viral replication (compared to LAI) and a 50% reduction of systemic CD4+ T cells (>90% for LAI) demonstrating the importance of CD4 downregulation. These results also demonstrate that functions other than CD4 downregulation enhanced viral replication and pathogenesis of LAINeffs?-1 and LAINeffs?-13 compared to LAINeffs. To gain insight into the nature of these activities, we constructed the double mutant P72A/P75A. Multiple Nef activities can be negated by mutating the SH3 domain binding site (P72Q73V74P75L76R77) to P72A/P75A and this mutation does not affect CD4 downregulation. Virus with nef mutated to P72A/P75A closely resembled the wild-type virus in vivo as viral replication and pathogenesis was not significantly altered. Unlike LAINeffs described above, the P72A/P75A mutation had a very weak tendency to revert to wild type sequence. Conclusions The in vivo phenotype of Nef is significantly dependent on CD4 downregulation but minimally on the numerous Nef activities that require an intact SH3 domain binding motif. These results suggest that CD4 downregulation plus one or more unknown Nef activities contribute to enhanced viral replication and pathogenesis and are suitable targets for anti-HIV therapy. Enforced evolution studies in BLT mice will greatly facilitate identification of these critical activities.

2013-01-01

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Reconstitution and functional analysis of kinetochore subcomplexes  

PubMed Central

Kinetochores are multifunctional supercomplexes that link chromosomes to dynamic microtubule tips. Groups of proteins from the kinetochore are arranged into distinct subcomplexes that co-purify under stringent conditions and cause similar phenotypes when mutated. By co-expressing all the components of a given subcomplex from a polycistronic plasmid in bacteria, many labs have had great success in purifying active subcomplexes. This has enabled the study of how the microtubule binding subcomplexes of the kinetochore interact with both the microtubule lattice and dynamic microtubule tips. Here we outline methods for rapid cloning of polycistronic vectors for expression of kinetochore subcomplexes, their purification, and techniques for functional analysis using Total Internal Reflect