Fibrosis and cirrhosis: regression with nucleoside/nucleotide analogs

2013 ◽  
Author(s):  
Maria Guido ◽  
Flavia Bortolotti
Keyword(s):  
Nucleotide Analogs

Ultrastructural analysis of the spatial distribution of MRNA

1992 ◽  
Vol 50 (1) ◽  
pp. 552-553
Author(s):  
Gary Bassell ◽  
Robert H. Singer
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
In Situ Hybridization ◽  
High Resolution ◽  
Nucleic Acids ◽  
Colloidal Gold ◽  
Dna Probe ◽  
Nucleotide Analogs ◽  
Gold Particles

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.

Modulation of Hepatic MRP3/ABCC3 by Xenobiotics and Pathophysiological Conditions: Role in Drug Pharmacokinetics

2019 ◽  
Vol 26 (7) ◽  
pp. 1185-1223 ◽  
Author(s):  
Carolina I. Ghanem ◽  
Jose E. Manautou
Keyword(s):  
Abc Transporters ◽  
Basolateral Membrane ◽  
Clinical Use ◽  
Nucleotide Analogs ◽  
Synthetic Drugs ◽  
The Family ◽  
Hepatic Transporter ◽  
Related Proteins ◽  
Drug Pharmacokinetics ◽  
Conjugated Metabolites

Liver transporters play an important role in the pharmacokinetics and disposition of pharmaceuticals, environmental contaminants, and endogenous compounds. Among them, the family of ATP-Binding Cassette (ABC) transporters is the most important due to its role in the transport of endo- and xenobiotics. The ABCC sub-family is the largest one, consisting of 13 members that include the cystic fibrosis conductance regulator (CFTR/ABCC7); the sulfonylurea receptors (SUR1/ABCC8 and SUR2/ABCC9) and the multidrug resistanceassociated proteins (MRPs). The MRP-related proteins can collectively confer resistance to natural, synthetic drugs and their conjugated metabolites, including platinum-containing compounds, folate anti-metabolites, nucleoside and nucleotide analogs, among others. MRPs can be also catalogued into "long" (MRP1/ABCC1, -2/C2, -3/C3, -6/C6, and -7/C10) and "short" (MRP4/C4, -5/C5, -8/C11, -9/C12, and -10/C13) categories. While MRP2/ABCC2 is expressed in the canalicular pole of hepatocytes, all others are located in the basolateral membrane. In this review, we summarize information from studies examining the changes in expression and regulation of the basolateral hepatic transporter MPR3/ABCC3 by xenobiotics and during various pathophysiological conditions. We also focus, primarily, on the consequences of such changes in the pharmacokinetic, pharmacodynamic and/or toxicity of different drugs of clinical use transported by MRP3.

Nonproteolyzed Form of DNA-Polymerase ε from T-Cell Spontaneous Lymphoma of Sprague-Dawley Inbred Rat: Isolation and Characterization

1998 ◽  
Vol 63 (5) ◽  
pp. 723-731 ◽  
Author(s):  
Gabriel Birkuš ◽  
Pavel Kramata ◽  
Ivan Votruba ◽  
Berta Otová ◽  
Miroslav Otmar ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Sedimentation Coefficient ◽  
Isolation Procedure ◽  
Sprague Dawley ◽  
Nucleotide Analogs ◽  
Isolation And Characterization ◽  
Inbred Rats ◽  
Catalyzed Reactions ◽  
Inbred Rat

Using a simple isolation procedure and selective assay for the determination of enzyme activity the nonproteolyzed and proteolyzed form of DNA-polymerase ε (pol ε and pol ε*) from the lymphoma of Sprague-Dawley inbred rats were purified. Nonproteolyzed pol ε is composed of two subunits (240 000 and 50 000) with sedimentation coefficient 10.5 S, while the subunit composition of pol ε* was 145 000 and 73 000. Estimated Km values for dATP and dGTP as well as Ki values for acyclic nucleotide analogs (PMEApp, HPMPApp and PMEDAPpp) in pol ε and pol ε* catalyzed reactions have shown that a proteolysis probably does not affect pol ε binding site for dNTPs. Both enzymes (pol ε and pol ε*) possess 3'-5'-exonuclease activity with different Km for 3'-OH end of template poly dA-oligo dT18 (1.6 μmol/l and 0.36 μmol/l, respectively).

[5-(Adenin-9-yl)-5-deoxy-L-pentofuranosyl]phosphonates - A Novel Type of Nucleotide Analogs Related to HPMPA. II. Synthesis of L-ribo and L-xylo Configurated Derivatives by Recyclization of Diethyl (5-RS)-[1,2-O-Isopropylidene-5-O-methanesulfonyl-D-pentofuranos-5-C-yl]phosphonates under Acidic Conditions

1993 ◽  
Vol 58 (9) ◽  
pp. 2180-2196 ◽  
Author(s):  
Miroslav Otmar ◽  
Ivan Rosenberg ◽  
Milena Masojídková ◽  
Antonín Holý
Keyword(s):  
Phosphonic Acid ◽  
Trifluoroacetic Acid ◽  
Recyclization Reaction ◽  
Nucleotide Analogs ◽  
Acidic Conditions

Further cyclic analogs of the antiviral (S)-9-(3-hydroxy-2-phosphonomethoxypropyl)adenine (I) were prepared: both anomers of [5-(adenin-9-yl)-5-doxy-L-ribofuranosyl]phosphonic acid (α-IId and β-IId) and [5-(adenin-9-yl)-5-doxy-α-L-ribofuranosyl]phosphonic acid (IIe). Recyclization reaction of diethyl (5RS-(3-O-benzyl-1,2-O-isopropylidene-5-O-methanesulfonyl-D-ribofuranos-5-C-yl)phosphonate (IVb) and diethyl (5RS-(3-O-benzyl-1,2-O-isopropylidene-5-O-methanesulfonyl-D-xylofuranos-5-C-yl)phosphonate (IVd) in trifluoroacetic acid led to cyclic aldehydes Va and Vb which were reduced to diethyl α- and β-L-ribofuranosylphosphonates VIb and α-L-xylofuranosylphosphonate VIIb. Conversion to the protected 5-O-tosylates VId and VIId, followed by reaction with adenine and deprotection, afforded the mentioned nucleotide analogs IId and IIe. An attempt to prepare L-pentofuranosylphosphonates Vc and XIII, suitable for the synthesis of nucleotide analogs of 3-deoxy-L-erythro and L-xylo configuration (IIf and IIg, respectively) by the recyclization reaction of the corresponding 5-O-methanesulfonyl derivatives IVf and XIIb failed. In this case, anhydro derivatives IXa, XVa and XVIa were isolated and identified.

scholarly journals A GTPase controls cell-substrate adhesion in Xenopus XTC fibroblasts.

1992 ◽  
Vol 118 (5) ◽  
pp. 1235-1244 ◽  
Author(s):  
M H Symons ◽  
T J Mitchison
Keyword(s):  
Control Cell ◽  
Response To Treatment ◽  
Nucleotide Analogs ◽  
Cell Contractility ◽  
Cell Rounding ◽  
Substrate Adhesion ◽  
Cell Substrate ◽  
Adhesive Interactions ◽  
Cell Substrate Adhesion ◽  
Gamma S

Cell-substrate adhesion is crucial at various stages of development and for the maintenance of normal tissues. Little is known about the regulation of these adhesive interactions. To investigate the role of GTPases in the control of cell morphology and cell-substrate adhesion we have injected guanine nucleotide analogs into Xenopus XTC fibroblasts. Injection of GTP gamma S inhibited ruffling and increased spreading, suggesting an increase in adhesion. To further investigate this, we made use of GRGDSP, a peptide which inhibits binding of integrins to vitronectin and fibronectin. XTC fibroblasts injected with non-hydrolyzable analogs of GTP took much more time to round up than mock-injected cells in response to treatment with GRGDSP, while GDP beta S-injected cells rounded up in less time than controls. Injection with GTP gamma S did not inhibit cell rounding induced by trypsin however, showing that cell contractility is not significantly affected by the activation of GTPases. These data provide evidence for the existence of a GTPase which can control cell-substrate adhesion from the cytoplasm. Treatment of XTC fibroblasts with the phorbol ester 12-o-tetradecanoylphorbol-13-acetate reduced cell spreading and accelerated cell rounding in response to GRGDSP, which is essentially opposite to the effect exerted by non-hydrolyzable GTP analogs. These results suggest the existence of at least two distinct pathways controlling cell-substrate adhesion in XTC fibroblasts, one depending on a GTPase and another one involving protein kinase C.

scholarly journals Biochemical Studies on the Mechanism of Human Immunodeficiency Virus Type 1 Reverse Transcriptase Resistance to 1-(β-d-Dioxolane)Thymine Triphosphate

2007 ◽  
Vol 51 (6) ◽  
pp. 2078-2084 ◽  
Author(s):  
Johan Lennerstrand ◽  
Chung K. Chu ◽  
Raymond F. Schinazi
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Nucleoside Analogs ◽  
Nucleotide Analogs ◽  
Immunodeficiency Virus ◽  
Large Panel ◽  
Tenofovir Diphosphate

ABSTRACT A large panel of drug-resistant mutants of human immunodeficiency virus type 1 reverse transcriptase (RT) was used to study the mechanisms of resistance to 1-(β-d-dioxolane)thymine triphosphate (DOT-TP) and other nucleotide analogs. RT containing thymidine analog-associated mutations (TAM) or RT with a T69S-SG insertion in combination with TAM removed 3′-azido-3′-deoxythymidine-5′-monophosphate or tenofovir more efficiently than DOT-monophosphate from chain-terminated DNA primer/template through ATP-mediated pyrophosphorolysis. For non-ATP-dependent discrimination toward DOT-TP, high levels of resistance were found for RT bearing the Q151M mutation with family mutations, while RT bearing only the M184V or the Y115F mutation conferred no resistance to DOT-TP. A lower degree of resistance to DOT-TP than to tenofovir diphosphate or carbovir-TP was found for RT containing the K65R mutation. In the present studies, 1-(β-d-dioxolane)guanine triphosphate, another nucleotide with a dioxolane sugar moiety, showed a resistance profile similar to that of DOT-TP. The results suggest that DOT, compared with other approved nucleoside analogs, is overall more resilient to mutations such as TAM, M184V, and K65R, which are commonly found in viruses derived from subjects failing multinucleoside therapy.

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