Football Players' Perceptions of Future Risk of Concussion and Concussion-Related Health Outcomes

Concussion is increasingly recognized as a risk of participation in contact and collision sports. There have been few examinations of athletes' perceptions of their susceptibility to concussion or concussion-related health consequences. We examine college football players' perceptions of their risk of sustaining a concussion and concussion-related health consequences in their future, whether these perceptions change over time, and how concussion history is related to perceived future risk of concussion and concussion-related health consequences. A survey was administered to National Collegiate Athletic Association Division I Football Championship Series athletes on 10 teams in 2013 and to nine of those teams in 2014. Athletes answered questions assessing their perceptions of concussion and potential concussion-related health consequences. Approximately 40% of athletes believed there was a strong possibility that they would sustain a concussion in the future, while approximately one-in-four thought a concussion would make them miss a few games. About one-in-10 athletes predicted dementia, Alzheimer's disease, or chronic traumatic encephalopathy would develop from concussions. These beliefs were stronger among athletes who had sustained previous concussions. Across the two years studied, athletes' perceptions of the risk of concussion and missing a few games because of concussion decreased significantly. Overall, a substantial proportion of college football players believe they will have long-term health consequences as a result of sustaining sport-related concussions. The true incidence and prevalence of many of these outcomes are unknown. Further research is needed to determine whether athletes have an accurate perception of the risks of these outcomes developing.

LLY-507, a Cell-active, Potent, and Selective Inhibitor of Protein-lysine Methyltransferase SMYD2

SMYD2 is a lysine methyltransferase that catalyzes the monomethylation of several protein substrates including p53. SMYD2 is overexpressed in a significant percentage of esophageal squamous primary carcinomas, and that overexpression correlates with poor patient survival. However, the mechanism(s) by which SMYD2 promotes oncogenesis is not understood. A small molecule probe for SMYD2 would allow for the pharmacological dissection of this biology. In this report, we disclose LLY-507, a cell-active, potent small molecule inhibitor of SMYD2. LLY-507 is >100-fold selective for SMYD2 over a broad range of methyltransferase and non-methyltransferase targets. A 1.63-Å resolution crystal structure of SMYD2 in complex with LLY-507 shows the inhibitor binding in the substrate peptide binding pocket. LLY-507 is active in cells as measured by reduction of SMYD2-induced monomethylation of p53 Lys³⁷⁰ at submicromolar concentrations. We used LLY-507 to further test other potential roles of SMYD2. Mass spectrometry-based proteomics showed that cellular global histone methylation levels were not significantly affected by SMYD2 inhibition with LLY-507, and subcellular fractionation studies indicate that SMYD2 is primarily cytoplasmic, suggesting that SMYD2 targets a very small subset of histones at specific chromatin loci and/or non-histone substrates. Breast and liver cancers were identified through in silico data mining as tumor types that display amplification and/or overexpression of SMYD2. LLY-507 inhibited the proliferation of several esophageal, liver, and breast cancer cell lines in a dose-dependent manner. These findings suggest that LLY-507 serves as a valuable chemical probe to aid in the dissection of SMYD2 function in cancer and other biological processes.

Diastereoselective synthesis of a spironoraristeromycin using an acylnitroso Diels-Alder reaction

The tert-butyl N-hydroxycarbamate-derived nitroso reagent 1 reacted with N-Cbz-protected spirocyclic diene 2 to provide spirocycloadduct 3. Here we describe the efficient conversion of 3 into the novel carbocyclic nucleoside spironoraristeromycin 4.

Qualification of cardiac troponin I concentration in mouse serum using isoproterenol and implementation in pharmacology studies to accelerate drug development

Cardiac troponin I is a useful biomarker of myocardial injury, but its use in mice and application to early drug discovery are not well described. The authors investigated the relationship between cTnI concentration in serum and histologic lesions in heart tissue from mice treated with isoproterenol (ISO). Cardiac TnI concentrations in serum increased in a dose-dependant manner and remained increased twenty-four to forty-eight hours after a single administration of isoproterenol. Increased cTnI concentration was of greater magnitude and longer duration than increased fatty acid binding protein 3 concentration, aspartate aminotransferase activity, and creatine kinase activity in serum. Isoproterenol-induced increases in cTnI concentrations were both greater and more sustained in BALB/c than in CD1 mice and correlated with incidence and severity of lesions observed in heart sections from both strains. In drug development studies in BALB/c mice with novel kinase inhibitors, cTnI concentration was a reliable stand-alone biomarker of cardiac injury and was used in combination with measurements of in vivo target inhibition to demonstrate an off-target contribution to cardiotoxicity. Additional attributes, including low cost and rapid turnaround time, made cTnI concentration in serum invaluable for detecting cardiotoxicity, exploring structure-activity relationships, and prioritizing development of compounds with improved safety profiles early in drug discovery.

Syntheses of new spirocarbocyclic nucleoside analogs using iminonitroso Diels-Alder reactions

N-Cbz- and Boc-protected spirocyclic dienes were prepared by dialkylation of cyclopentadiene. These dienes coupled efficiently in a series of iminonitroso Diels-Alder reactions to produce a series of new spirocyclic adducts. Hydrogenolysis of these adducts afforded new spirocycles that contain multiple handles for further functionalization. Furthermore, stereocontrolled dihydroxylation and reductive cleavage of the spirocyclic adducts generated versatile scaffolds for the syntheses and derivatization of novel spirocyclic carbocyclic nucleoside analogs.

Anthranilamide inhibitors of factor Xa

SAR about the B-ring of a series of N(2)-aroyl anthranilamide factor Xa (fXa) inhibitors is described. B-ring o-aminoalkylether and B-ring p-amine probes of the S1' and S4 sites, respectively, afforded picomolar fXa inhibitors that performed well in in vitro anticoagulation assays.

The development of potent and selective bisarylmaleimide GSK3 inhibitors

Many 3-aryl-4-(1,2,3,4-tetrahydro[1,4]diazepino[6,7,1-hi]indol-7-yl)maleimides exhibit potent GSK3 inhibitory activity (<100 nM IC(50)), although few show significant selectivity (>100x) versus CDK2, CDK4, or PKCbetaII. However, combining 3-(imidazo[1,2-a]pyridin-3-yl), 3-(pyrazolo[1,5-a]pyridin-3-yl) or aza-analogs with a 4-(2-acyl-(1,2,3,4-tetrahydro[1,4]diazepino[6,7,1-hi]indol-7-yl)) group on the maleimide resulted in very potent inhibitors of GSK3 (</=5 nM) with >160 to >10,000-fold selectivity versus CDK2/4 and PKCbetaII. These compounds also inhibited tau phosphorylation in cells and were effective in lowering plasma glucose in a rat model of type 2 diabetes (ZDF rat).

Substituted 3-imidazo[1,2-a]pyridin-3-yl- 4-(1,2,3,4-tetrahydro-[1,4]diazepino-[6,7,1-hi]indol-7-yl)pyrrole-2,5-diones as highly selective and potent inhibitors of glycogen synthase kinase-3

Glycogen synthase kinase-3 (GSK3) is involved in signaling from the insulin receptor. Inhibitors of GSK3 are expected to effect lowering of plasma glucose similar to insulin, making GSK3 an attractive target for the treatment of type 2 diabetes. Herein we report the discovery of a series of potent and selective GSK3 inhibitors. Compounds 7-12 show oral activity in an in vivo model of type II diabetes, and 9 and 12 have desirable PK properties.

Design and synthesis of statine-Containing BACE inhibitors

Utilizing structure-based techniques and solid-phase synthesis, statine-based tetrapeptide BACE inhibitors were designed and synthesized using a heptapeptide BACE transition-state mimetic, 1, as the starting point. Structure-activity relationship studies at the P(3), P(2), and P(2)' positions as well as the N-terminal capping group on scaffold 5 led to the discovery of potent inhibitors 27, 32, and 34 (IC(50) <100 nM). In addition, computational analysis and the X-ray structure of BACE-inhibitor 38 are discussed.

Influenza virus carrying neuraminidase with reduced sensitivity to oseltamivir carboxylate has altered properties in vitro and is compromised for infectivity and replicative ability in vivo

Oseltamivir phosphate (Tamiflu, Ro 64-0796) is the first orally administered neuraminidase (NA) inhibitor approved for use in treatment and prevention of influenza virus infection in man. Oseltamivir phosphate is the pro-drug of the active metabolite oseltamivir carboxylate (Ro 64-0802). Extensive monitoring throughout the oseltamivir development programme has identified a very low incidence of patients who have carried drug-resistant virus. The predominant mutation seen is the substitution of arginine for lysine at position 292 of the viral NA. The fitness of clinically isolated influenza virus A/Sydney/5/97 (H3N2) carrying this mutation was markedly reduced in animal models of influenza virus infection. The infectivity and replicative abilities of R292K mutant virus were reduced by at least 2 logs in a mouse model of influenza infection and by 2 and 4 logs, respectively, in the ferret model. Pathogenicity of R292K influenza virus A/Sydney/5/97 was reduced in ferrets as measured by inflammatory and febrile responses at least in parallel to the decrease in replicative ability. The data indicate that the R292K NA mutation compromises viral fitness such that virus carrying this mutation is unlikely to be of significant clinical consequence in man.

1,2-Dibenzamidobenzene inhibitors of human factor Xa

High-throughput screening of a combinatorial library of diamidophenols yielded lead compounds with the ability to inhibit human factor Xa (fXa) at micromolar concentrations (e.g. compound 4, fXa apparent K(ass) = 0.64 x 10(6) L/mol). SAR studies in this novel structural series of fXa inhibitors showed that the phenolic hydroxyl group was not essential for activity. The best activity was found in substituted 1,2-dibenzamidobenzenes in which the phenyl group of one benzoyl group (A-ring) was substituted in the 4-position with relatively small lipophilic or polarizable groups such as methoxy, vinyl, or chloro and the phenyl group of the other benzoyl group (B-ring) was substituted in the 4-position with larger lipophilic groups such as tert-butyl or dimethylamino. The central phenyl ring (C-ring) tolerated a wide variety of substituents, but methoxy, methanesulfonamido, hydroxyl, and carboxyl substitution produced slightly higher levels of activity than other substituents when present in combination with favorable B-ring substitution. Methylation of the amide nitrogen atoms was found to greatly decrease activity. Compound 12 is the highest affinity fXa inhibitor in this group of compounds, having fXa apparent K(ass) = 25.5 x 10(6) L/mol, about 40x more active than the original lead. This lead series does not show potent inhibition of human thrombin. A model for the binding of these ligands to the fXa active site is proposed. The model is consistent with the observed SAR and can serve to guide future SAR studies.

DETERMINANTS OF INTRAMYOCARDIAL PRESSURE IN THE CAT

Determinants of intramyocardial pressure in the cat were investigated by means of a small latex tube inserted into the wall of the left ventricle. Maximal intramyocardial pressures were generally below carotid systolic pressures. Rhythmic variations in intramyocardial pressure occurred and were related to pulmonary ventilation. There was no evidence of efferent vagal activity on the left ventricle. Sympathetic stimulation increased and sympathetic blockade (with Pronethalol) decreased intramyocardial pressure. Intramyocardial pressure was increased by venous infusions and by constriction of the aorta.

Site-directed mutagenesis with an expanded genetic code

A biosynthetic method has been developed that makes possible the site-specific incorporation of a large number of amino acids and analogues within proteins. In this approach, an amber suppressor tRNA chemically aminoacylated with the desired amino acid incorporates this amino acid site specifically into a protein in response to an amber codon introduced at the corresponding position in the protein's DNA sequence. Using this method, precise changes within a protein can be made to address detailed structure-function questions. A series of fluorinated tyrosine analogues and linear, branched, and cyclic hydrophobic amino acids have been used to determine the impact of hydrogen bonding and hydrophobic packing, respectively, on protein stability. Glutamate analogues and conformationally restricted amino acids have been used to probe the mechanisms of staphylococcal nuclease and ras. In addition, this technique has been used to construct photocaged proteins and proteins containing photoaffinity labels, spin labels, and isotopic labels at specific positions in the protein sequence suitable for biophysical studies.

Probing protein stability with unnatural amino acids

Unnatural amino acid mutagenesis, in combination with molecular modeling and simulation techniques, was used to probe the effect of side chain structure on protein stability. Specific replacements at position 133 in T4 lysozyme included (i) leucine (wt), norvaline, ethylglycine, and alanine to measure the cost of stepwise removal of methyl groups from the hydrophobic core, (ii) norvaline and O-methyl serine to evaluate the effects of side chain solvation, and (iii) leucine, S,S-2-amino-4-methylhexanoic acid, and S-2-amino-3-cyclopentylpropanoic acid to measure the influence of packing density and side chain conformational entropy on protein stability. All of these factors (hydrophobicity, packing, conformational entropy, and cavity formation) significantly influence protein stability and must be considered when analyzing any structural change to proteins.

Site-specific incorporation of novel backbone structures into proteins

A number of unnatural amino acids and amino acid analogs with modified backbone structures were substituted for alanine-82 in T4 lysozyme. Replacements included alpha,alpha-disubstituted amino acids, N-alkyl amino acids, and lactic acid, an isoelectronic analog of alanine. The effects of these electronic and structural perturbations on the stability of T4 lysozyme were determined. The relatively broad substrate specificity of the Escherichia coli protein biosynthetic machinery suggests that a wide range of backbone and side-chain substitutions can be introduced, allowing a more precise definition of the factors affecting protein stability.

Hoogsteen base pairs proximal and distal to echinomycin binding sites on DNA

Forms of the DNA double helix containing non-Watson-Crick base-pairing have been discovered recently based on x-ray diffraction analysis of quinoxaline antibiotic-oligonucleotide complexes. In an effort to find evidence for Hoogsteen base-pairing at quinoxaline-binding sites in solution, chemical "footprinting" (differential cleavage reactivity) of echinomycin bound to DNA restriction fragments was examined. We report that purines (A greater than G) in the first and/or fourth base-pair positions of occupied echinomycin-binding sites are hyperreactive to diethyl pyrocarbonate. The correspondence of the solid-state data and the sites of diethyl pyrocarbonate hyperreactivity suggests that diethyl pyrocarbonate may be a sensitive reagent for the detection of Hoogsteen base-pairing in solution. Moreover, a 12-base-pair segment of alternating A-T DNA, which is 6 base pairs away from the nearest strong echinomycin-binding site, is also hyperreactive to diethyl pyrocarbonate in the presence of echinomycin. This hyperreactive segment may be an altered form of right-handed DNA that is entirely Hoogsteen base-paired.

Tricuspid valve replacement in rheumatic heart disease

The diagnosis of tricuspid valve disease is often difficult; the best treatment is not yet established. Twenty patients had tricuspid valve replacements at St. Thomas's Hospital as part of multiple valve replacement procedures. The hospital mortality was 25%, most deaths being due to a low cardiac output causing hepatorenal failure. Preoperative cardiac cachexia had a fatal outcome in all cases. Except in two instances, surviving patients returned to a satisfactory level of activity.

Triple Starr valve replacement

Of nine patients who have had triple valve replacements for organic rheumatic triple valve disease two died in the postoperative period from inadequate myocardial reserve, and a third died four months later from cerebral embolism originating from clot on the left atrial wall. The remainder are well and, except for one, leading normal lives. Though cardiac transplantation has been recommended and used successfully for triple valve disease by Cooley, it is suggested that the long-term outlook today of triple valve replacement is likely to be better than that of transplantation.

Valvoplasty for abnormalities of posterior (mural) cusp of the mitral valve

Five patients with abnormalities of the chordae tendineae of the posterior (mural) cusp of the mitral valve have been treated by plication of the cusp, annulus, and atrium in continuity (modified McGoon valvoplasty). They had acute symptoms with physical signs characterized by sinus rhythm and an apical pansystolic murmur radiating to the base of the heart. Investigation showed high left atrial systolic pressures in small atria. Apart from one patient who died of cerebral air embolism with a good haemodynamic result, all were immediately improved and had smooth post-operative courses. Improvement was maintained at follow-up without embolic complications despite stopping anticoagulants.

The effects of alteration of CO2 and pH on intestinal blood flow in the cat

1. The effect of alteration of arterial blood pH on intestinal blood flow in the cat has been determined under conditions of constant perfusion pressure.2. Arterial blood pH was altered over the range 7.12-7.70 by infusion of acid and alkali. When end-tidal CO(2) was held constant, there was no change in intestinal blood flow.3. When arterial blood pH was altered over the range 7.19-7.55 by the administration of CO(2) at constant respiratory volume and rate, flow increased with increasing CO(2).4. The intestinal vascular bed was less responsive to noradrenaline at pH 7.2 than at pH 7.6. The change in sensitivity was evident when end-tidal CO(2) was controlled and depended therefore on a change in hydrogenion concentration.5. The dilator effect of CO(2) did not depend upon alteration of sensitivity to noradrenaline since it was seen after adrenergic blockade.

Some observations on 'autoregulatory escape' in cat intestine

1. ;Autoregulatory escape' (Folkow, Lewis, Lundgren, Mellander & Wallentin, 1964a) in which intestinal blood flow escapes from the constrictor influence of splanchnic nerve stimulation, was investigated in the cat. Measurements were made of intestinal blood flow, movements and portal venous pH and oxygen content.2. ;Autoregulatory escape' was observed with sympathetic nerve stimulation and noradrenaline infusion. It did not occur during haemorrhage.3. The recovery of flow during noradrenaline infusion could not be explained by changes in intestinal motility or loss of effect of noradrenaline due to changes in portal venous hydrogen ion concentration.4. During a noradrenaline infusion there was a reduction in oxygen consumption associated with a fall in blood flow. During the period of ;autoregulatory escape', however, oxygen consumption increased. The significance of these observations is discussed.