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To assess the benefit of stereoscopic digital mammography in daily practice.

The optimization of the pharmacokinetic performance of various 2-pyridone-containing human rhinovirus (HRV) 3C protease (3CP) inhibitors following oral administration to either beagle dogs or CM-monkeys is described. The molecules described in this work are composed of a 2-pyridone-containing peptidomimetic binding determinant and an α,β-unsaturated ester Michael acceptor moiety which forms an irreversible covalent adduct with the active site cysteine residue of the 3C enzyme. Modification of the ester contained within these compounds is detailed along with alteration of the P2 substituent present in the peptidomimetic portion of the inhibitors. The pharmacokinetics of several inhibitors in both dogs and monkeys are described (7 h plasma concentrations after oral administration) along with their human plasma stabilities, stabilities in incubations with human, dog, and monkey microsomes and hepatocytes, Caco-2 permeabilities, and aqueous solubilities. Compounds containing an α,β-unsaturated ethyl ester fragment and either an ethyl or propargyl P2 moiety displayed the most promising combination of 3C enzyme inhibition (kobs/[I] 170 000−223 000 M^-1 s^-1), antiviral activity (EC50 = 0.047−0.058 μM, mean vs seven HRV serotypes), and pharmacokinetics following oral administration (7 h dog plasma levels = 0.248−0.682 μM; 7 h CM-monkey plasma levels = 0.057−0.896 μM).

Utilizing the tools of parallel synthesis and structure-based design, a new class of Michael acceptor-containing, irreversible inhibitors of human rhinovirus 3C protease (HRV 3CP) was discovered. These inhibitors are shown to inhibit HRV-14 3CP with rates of inactivation ranging from 886 to 31 400 M^-1 sec^-1. These inhibitors exhibit antiviral activity when tested against HRV-14 infected H1-HeLa cells, with EC50 values ranging from 1.94 to 0.15 μM. No cytotoxicity was observed at the limits of the assay concentration. A crystal structure of one of the more potent inhibitors covalently bound to HRV-2 3CP is detailed. These compounds were also tested against HRV serotypes other than type 14 and were found to have highly variable activities.

The structure-based design, chemical synthesis, and biological evaluation of various 2-pyridone-containing human rhinovirus (HRV) 3C protease (3CP) inhibitors are described. These compounds are comprised of a peptidomimetic binding determinant and a Michael acceptor moiety, which forms an irreversible covalent adduct with the active site cysteine residue of the 3C enzyme. The 2-pyridone-containing inhibitors typically display improved 3CP inhibition properties relative to related peptide-derived molecules along with more favorable antiviral properties. The cocrystal structure of one pyridone-derived 3CP inhibitor complexed with HRV-2 3CP is also described along with certain ab initio conformation analyses. Optimization of the 2-pyridone-containing compounds is shown to provide several highly active 3CP inhibitors (kobs/[I] > 500 000 M^-1 s^-1) that function as potent antirhinoviral agents (EC50 = <0.05 μM) against multiple virus serotypes in cell culture. One 2-pyridone-containing 3CP inhibitor is shown to be bioavailable in the dog after oral dosing (F = 48%).

A series of nonpeptide benzamide-containing inhibitors of human rhinovirus (HRV) 3C protease was identified using structure-based design. The design, synthesis, and biological evaluation of these inhibitors are reported. A Michael acceptor was combined with a benzamide core mimicking the P1 recognition element of the natural 3CP substrate. α,β-Unsaturated cinnamate esters irreversibly inhibited the 3CP and displayed antiviral activity (EC50 0.60 μM, HRV-16 infected H1-HeLa cells). On the basis of cocrystal structure information, a library of substituted benzamide derivatives was prepared using parallel synthesis on solid support. A 1.9 Å cocrystal structure of a benzamide inhibitor in complex with the 3CP revealed a binding mode similar to that initially modeled wherein covalent attachment of the nucleophilic cysteine residue is observed. Unsaturated ketones displayed potent reversible inhibition but were inactive in the cellular antiviral assay and were found to react with nucleophilic thiols such as DTT.

The structure-based design, chemical synthesis, and biological evaluation of various ketomethylene-containing human rhinovirus (HRV) 3C protease (3CP) inhibitors are described. These compounds are comprised of a peptidomimetic binding determinant and an ethyl propenoate Michael acceptor moiety which forms an irreversible covalent adduct with the active site cysteine residue of the 3C enzyme. The ketomethylene-containing inhibitors typically display slightly reduced 3CP inhibition activity relative to the corresponding peptide-derived molecules, but they also exhibit significantly improved antiviral properties. Optimization of the ketomethylene-containing compounds is shown to provide several highly active 3C protease inhibitors which function as potent antirhinoviral agents (EC90 = <1 μM) against multiple virus serotypes in cell culture.

The structure-based design, chemical synthesis, and biological evaluation of various human rhinovirus (HRV) 3C protease (3CP) inhibitors which incorporate P1 lactam moieties in lieu of an l-glutamine residue are described. These compounds are comprised of a tripeptidyl or peptidomimetic binding determinant and an ethyl propenoate Michael acceptor moiety which forms an irreversible covalent adduct with the active site cysteine residue of the 3C enzyme. The P1-lactam-containing inhibitors display significantly increased 3CP inhibition activity along with improved antirhinoviral properties relative to corresponding l-glutamine-derived molecules. In addition, several lactam-containing compounds exhibit excellent selectivity for HRV 3CP over several other serine and cysteine proteases and are not appreciably degraded by a variety of biological agents. One of the most potent inhibitors (AG7088, mean antirhinoviral EC90 ≈ 0.10 μM, n = 46 serotypes) is shown to warrant additional preclinical development to explore its potential for use as an antirhinoviral agent.

The investigation of tripeptide aldehydes as reversible covalent inhibitors of human rhinovirus (HRV) 3C protease (3CP) is reported. Molecular models based on the apo crystal structure of HRV-14 3CP and other trypsin-like serine proteases were constructed to approximate the binding of peptide substrates, generate transition state models of P1−P1‘ amide cleavage, and propose novel tripeptide aldehydes. Glutaminal derivatives have limitations since they exist predominantly in the cyclic hemiaminal form. Therefore, several isosteric replacements for the P1 carboxamide side chain were designed and incorporated into the tripeptide aldehydes. These compounds were found to be potent inhibitors of purified HRV-14 3CP with Kis ranging from 0.005 to 0.64 μM. Several have low micromolar antiviral activity when tested against HRV-14-infected H1-HeLa cells. The N-acetyl derivative 3 was also shown to be active against HRV serotypes 2, 16, and 89. High-resolution cocrystal structures of HRV-2 3CP, covalently bound to compounds 3, 15, and 16, were solved. These cocrystal structures were analyzed and compared with our original HRV-14 3CP−substrate and inhibitor models.

The structure-based design, chemical synthesis, and biological evaluation of peptide-derived human rhinovirus (HRV) 3C protease (3CP) inhibitors are described. These compounds incorporate various Michael acceptor moieties and are shown to irreversibly bind to HRV serotype 14 3CP with inhibition activities (kobs/[I]) ranging from 100 to 600 000 M^-1 s^-1. These inhibitors are also shown to exhibit antiviral activity when tested against HRV-14-infected H1-HeLa cells with EC50's approaching 0.50 μM. Extensive structure−activity relationships developed by Michael acceptor alteration are reported along with the evaluation of several compounds against HRV serotypes other than 14. A 2.0 Å crystal structure of a peptide-derived inhibitor complexed with HRV-2 3CP is also detailed.

The structure-based design, chemical synthesis, and biological evaluation of various peptide-derived human rhinovirus (HRV) 3C protease (3CP) inhibitors are described. These compounds are comprised of an ethyl propenoate Michael acceptor moiety and a tripeptidyl binding determinant. The systematic modification of each amino acid residue present in the binding determinant as well as the N-terminal functionality is described. Such modifications are shown to provide irreversible HRV-14 3CP inhibitors with anti-3CP activities (kobs/[I]) ranging from 60 to 280 000 M^-1 s^-1 and antiviral EC50's which approach 0.15 μM. An optimized inhibitor which incorporates several improvements identified by the structure−activity studies is also described. This molecule displays very rapid irreversible inhibition of HRV-14 3CP (kobs/[I] = 800 000 M^-1 s^-1) and potent antiviral activity against HRV-14 in cell culture (EC50 = 0.056 μM). A 1.9 Å crystal structure of an S-alkylthiocarbamate-containing inhibitor complexed with HRV-2 3CP is also detailed.

The design, synthesis, biochemical, and biological evaluation of a novel series of 5-thia-2,6-diamino-4(3H)-oxopyrimidine inhibitors of glycinamide ribonucleotide transformylase (GART) are described. The compounds were designed using the X-ray crystal structure of human GART. The monocyclic 5-thiapyrimidinones were synthesized by coupling an alkyl thiol with 5-bromo-2,6-diamino-4(3H)-pyrimidinone, 20. The bicyclic compounds were prepared in both racemic and diastereomerically pure forms using two distinct synthetic routes. The compounds were found to have human GART Kis ranging from 30 μM to 2 nM. The compounds inhibited the growth of both L1210 and CCRF-CEM cells in culture with potencies down to the low nanomolar range and were found to be selective for the de novo purine biosynthesis pathway. The most potent inhibitors had 2,5-disubstituted thiophene rings attached to the glutamate moiety. Placement of a methyl substituent at the 4-position of the thiophene ring to give compounds 10, 18, and 19 resulted in inhibitors with significantly decreased mFBP affinity.

The design, synthesis, and biological evaluation of reversible, nonpeptidic inhibitors of human rhinovirus (HRV) 3C protease (3CP) are reported. A novel series of 2,3-dioxindoles (isatins) were designed that utilized a combination of protein structure-based drug design, molecular modeling, and structure−activity relationship (SAR). The C-2 carbonyl of isatin was envisioned to react in the active site of HRV 3CP with the cysteine responsible for catalytic proteolysis, thus forming a stabilized transition state mimic. Molecular-modeling experiments using the apo crystal structure of human rhinovirus-serotype 14 (HRV-14) 3CP and a peptide substrate model allowed us to design recognition features into the P1 and P2 subsites, respectively, from the 5- and 1-positions of isatin. Attempts to optimize recognition properties in the P1 subsite using SAR at the 5-position were performed. In addition, a series of ab initio calculations were carried out on several 5-substituted isatins to investigate the stability of sulfide adducts at C-3. The inhibitors were prepared by general synthetic methods, starting with commercially available 5-substituted isatins in nearly every case. All compounds were tested for inhibition of purified HRV-14 3CP. Compounds 8, 14, and 19 were found to have excellent selectivity for HRV-14 3CP compared to other proteolytic enzymes, including chymotrypsin and cathepsin B. Selected compounds were assayed for antiviral activity against HRV-14-infected HI-HeLa cells. A 2.8 Å cocrystal structure of derivative 19 covalently bound to human rhinovirus-serotype 2 (HRV-2) 3CP was solved and revealed that the isatin was situated in essentially the same conformation as modeled.

We have undertaken micromagnetic calculations of domain configurations in submicron cobalt dots. Good agreement is shown between calculated and measured hysteresis loops as well as between calculated and domain patterns observed by magnetic force microscopy. It appears also that the nucleation mechanism in a formerly saturated sample depends strongly on dot thickness. These changes in the nucleation mechanism and in domain evolution with applied field are found to be responsible for the wide variety of magnetisation configurations observed at zero applied field.

Magnetic submicron cobalt dots with geometrical dimensions comparable to the width of magnetic domains are studied by high resolution magnetic force microscopy. This study reveals a variety of intricate domain patterns controlled by the details of the dot geometry. The width of the geometrically constrained magnetic domains can be tuned by changing the thickness of the dots. Theoretical investigation of the domain structure in the dots accurately describes the domain pattern and the number of domains per dot.

AIM: To assess the utility of bedside ultrasound performed by an emergency physician in adults undergoing diagnostic lumbar puncture. METHOD: Ultrasound was used as the primary means of determining the site of skin puncture, angle of needle advancement and depth needed to access the subarachnoid space. RESULTS: Cerebrospinal fluid was obtained from 36 of 39 patients (92.3%) in the first interspinous space attempted. CONCLUSIONS: The ultrasonographically measured depth of the dura mater correlates strongly with the final needle depth.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.