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Dive into the research topics where Sammy Ray Shaver is active.

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Featured researches published by Sammy Ray Shaver.


Bioorganic & Medicinal Chemistry Letters | 2001

Synthesis and P2Y receptor activity of a series of uridine dinucleoside 5′-polyphosphates

William Pendergast; Benjamin R. Yerxa; James G. Douglass; Sammy Ray Shaver; Robert W. Dougherty; Catherine C. Redick; Ingrid F Sims; Janet L. Rideout

A series of dinucleoside 5-polyphosphates UpnU (n = 2-7) was synthesized. Their relative potencies as agonists at the G-protein-coupled receptors P2Y1, P2Y2, P2Y4, and P2Y6 were determined by intracellular calcium measurements using fluorescent imaging techniques. The correlation of phosphate chain length to activities at these receptors is discussed.


Purinergic Signalling | 2005

Structure–activity relationships of dinucleotides: Potent and selective agonists of P2Y receptors

Sammy Ray Shaver; Janet L. Rideout; William Pendergast; James G. Douglass; Edward G. Brown; José L. Boyer; Roshni I. Patel; Catherine C. Redick; Arthur C. Jones; Maryse Picher; Benjamin R. Yerxa

Dinucleoside polyphosphates act as agonists on purinergic P2Y receptors to mediate a variety of cellular processes. Symmetrical, naturally occurring purine dinucleotides are found in most living cells and their actions are generally known. Unsymmetrical purine dinucleotides and all pyrimidine containing dinucleotides, however, are not as common and therefore their actions are not well understood. To carry out a thorough examination of the activities and specificities of these dinucleotides, a robust method of synthesis was developed to allow manipulation of either nucleoside of the dinucleotide as well as the phosphate chain lengths. Adenosine containing dinucleotides exhibit some level of activity on P2Y1 while uridine containing dinucleotides have some level of agonist response on P2Y2 and P2Y6. The length of the linking phosphate chain determines a different specificity; diphosphates are most accurately mimicked by dinucleoside triphosphates and triphosphates most resemble dinucleoside tetraphosphates. The pharmacological activities and relative metabolic stabilities of these dinucleotides are reported with their potential therapeutic applications being discussed.


Journal of Medicinal Chemistry | 2008

Lipophilic Modifications to Dinucleoside Polyphosphates and Nucleotides that Confer Antagonist Properties at the Platelet P2Y12 Receptor

James G. Douglass; Roshni I. Patel; Benjamin R. Yerxa; Sammy Ray Shaver; Paul S. Watson; Krzysztof Bednarski; Robert Plourde; Catherine C. Redick; Kurt E. Brubaker; Arthur C. Jones; José L. Boyer

Platelet P2Y12 receptors play a central role in the regulation of platelet function and inhibition of this receptor by treatment with drugs such as clopidogrel results in a reduction of atherothrombotic events. We discovered that modification of natural and synthetic dinucleoside polyphosphates and nucleotides with lipophilic substituents on the ribose and base conferred P2Y12 receptor antagonist properties to these molecules producing potent inhibitors of ADP-mediated platelet aggregation. We describe methods for the preparation of these functionalized dinucleoside polyphosphates and nucleotides and report their associated activities. By analysis of these results and by deconstruction of the necessary structural elements through selected syntheses, we prepared a series of highly functionalized nucleotides, resulting in the selection of an adenosine monophosphate derivative (62) for further clinical development.


Fertility and Sterility | 2003

Selective P2Y2 receptor agonists stimulate vaginal moisture in ovariectomized rabbits

Kweonsik Min; Ricardo Munarriz; Benjamin R. Yerxa; Irwin Goldstein; Sammy Ray Shaver; Matthew S. Cowlen; Abdulmaged M. Traish

OBJECTIVE To determine the expression of P2Y(2) receptors in vaginal and cervical tissues and the effects of P2Y(2) receptor agonists INS45973 and INS365 on vaginal moisture. DESIGN Pilot in vivo and histological study using animal subjects. SETTING Experimental laboratory research. ANIMAL(S) Female New Zealand White rabbits were used for in vivo studies and female cynomolgus monkey (Macaca fascicularis) was used for in situ hybridization. INTERVENTION(S) Rabbits were kept intact or ovariectomized. Two weeks after ovariectomy, animals received daily vaginal instillation of vehicle or drugs for 16 days. MAIN OUTCOME MEASURE(S) Vaginal moisture was assessed in rabbits on 4 separate days during the treatment period. The P2Y(2) receptor mRNA distribution was assessed by in situ hybridization of monkey vagina and cervix. RESULT(S) Compared to control, vaginal moisture was significantly diminished in ovariectomized animals treated with vehicle. INS365 (8.1%) and INS45973 (0.9%) increased vaginal moisture in ovariectomized animals to levels that were comparable to or significantly higher than control animals, respectively. In situ hybridization studies indicated that P2Y(2) receptor mRNA was localized to endocervical and cervical gland, epithelium, and stratified squamous epithelium of the vagina. CONCLUSION(S) INS45973 and INS365 may interact with P2Y(2) receptors in the cervix and vagina to stimulate vaginal moisture in the estrogen (E)-deprived state. The P2Y(2) receptor agonists provide a potential nonhormonal alternative for treating vaginal dryness in postmenopausal women.


Nucleosides, Nucleotides & Nucleic Acids | 1997

4-SUBSTITUTED URIDINE 5'-TRIPHOSPHATES AS AGONISTS OF THE P2Y2 PURINERGIC RECEPTOR

Sammy Ray Shaver; William Pendergast; Suhaib Siddiqi; Benjamin R. Yerxa; Dallas K. Croom; Robert W. Dougherty; Michael K. James; A. Neil Jones; Janet L. Rideout

Abstract Uridine 5′-O-triphosphate (UTP) is a potent agonist of the purinergic receptor designated P2Y2. UTP is rapidly metabolized in human tissue. To find a compound with similar activity that may be more slowly metabolized, a series of 4-substituted uridine 5′-triphosphates were prepared and evaluated in a P2Y2 receptor second messenger assay.


Bioorganic & Medicinal Chemistry Letters | 2017

Design and optimization of highly-selective, broad spectrum fungal CYP51 inhibitors

Christopher M. Yates; Edward P. Garvey; Sammy Ray Shaver; Robert J. Schotzinger; William J. Hoekstra

While the orally-active azoles such as fluconazole and posaconazole are effective antifungal agents, they potently inhibit a broad range of off-target human cytochrome P450 enzymes (CYPs) leading to various safety issues (e.g., drug-drug interactions, liver, and reproductive toxicities). Recently we described the rationally-designed, antifungal agent VT-1161 that is more selective for fungal CYP51 than related human CYP enzymes such as CYP3A4. Herein, we describe the use of a homology model of Aspergillus fumigatus to design and optimize a novel series of highly selective, broad spectrum fungal CYP51 inhibitors. This series includes the oral antifungal VT-1598 that exhibits excellent potency against yeast, dermatophyte, and mold fungal pathogens.


Archive | 2000

Method of treating gastrointestinal tract disease with purinergic receptor agonists

Benjamin R. Yerxa; Janet L. Rideout; William Pendergast; Sammy Ray Shaver; Zhen Zhang; Ward M. Peterson; Matthew S. Cowlen


Archive | 1999

Method of promoting cervical and vaginal secretions

William Pendergast; Sammy Ray Shaver; David J. Drutz; Janet L. Rideout; Benjamin R. Yerxa


Archive | 2005

Non-nucleotide composition and method for inhibiting platelet aggregation

Robert Plourde; Sammy Ray Shaver; James G. Douglass; Paul S. Watson; José L. Boyer; Chi Tu; Melwyn Abreo; Lorenzo Josue Alfaro-Lopez; Yangbo Feng; Daniel F. Harvey; Tatyana V. Khasonova


Archive | 2005

Drug-eluting stents coated with non-nucleotide P2Y12 receptor antagonist compound

José L. Boyer; James G. Douglass; Sammy Ray Shaver

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Benjamin R. Yerxa

University of North Carolina at Chapel Hill

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