Intrasynovial triamcinolone treatment is not associated with incidence of acute laminitis

Background: Intra-synovial corticosteroid injections are commonly used in the treatment of equine orthopaedic disease, but corticosteroid administration is widely considered a risk factor for the development of laminitis. Despite a list of putative mechanisms and a number of case reports of steroid-induced laminitis, no case-control or cohort studies investigating the association between use of intra-synovial corticosteroids and acute laminitis have been published. Objectives: To quantify the risk of laminitis posed by intra-synovial triamcinolone acetonide (TA) administration in a mixed population of horses. Study design: Retrospective observational cohort study. Methods: Clinical records of horses registered with one large UK equine practice were reviewed retrospectively to identify all horses receiving intra-synovial TA treatment between 1 January 2007 and 31 December 2017. 1,510 horses were selected and records investigated for incidence of laminitis over a 4-month period following treatment. For each TA-treated horse, an untreated horse, individually matched by age, sex, date of treatment and client type, was selected from the clinical records. Untreated horses were then investigated for laminitis over the same 4-month period. Data was analysed in a 2×2 contingency table using Fisher’s exact test. Results: 489 horses were lost to follow-up and 55 horses were excluded, leaving 966 treated and matched, untreated horses. The incidence of laminitis over the 4-month study period in both groups was identical: 3/966 horses (0.31%) (95% C.I. [0.08%, 0.91%]), equivalent to 0.93 cases per 100 horses per year (P >0.9). Main limitations: Retrospective study; large proportion (489/1510) of horses lost to follow-up; large proportion of study population were racehorses; selection method resulted in disproportionate selection of horses born before 2013; similar incidence between groups may reflect existing risk-based selection by clinicians. Conclusions: Intra-synovial triamcinolone acetonide administration does not increase the risk of laminitis in this study population

Intrasynovial triamcinolone treatment is not associated with incidence of acute laminitis

Background: Intra-synovial corticosteroid injections are commonly used in the treatment of equine orthopaedic disease, but corticosteroid administration is widely considered a risk factor for the development of laminitis. Despite a list of putative mechanisms and a number of case reports of steroid-induced laminitis, no case-control or cohort studies investigating the association between use of intra-synovial corticosteroids and acute laminitis have been published. Objectives: To quantify the risk of laminitis posed by intra-synovial triamcinolone acetonide (TA) administration in a mixed population of horses. Study design: Retrospective observational cohort study. Methods: Clinical records of horses registered with one large UK equine practice were reviewed retrospectively to identify all horses receiving intra-synovial TA treatment between 1 January 2007 and 31 December 2017. 1,510 horses were selected and records investigated for incidence of laminitis over a 4-month period following treatment. For each TA-treated horse, an untreated horse, individually matched by age, sex, date of treatment and client type, was selected from the clinical records. Untreated horses were then investigated for laminitis over the same 4-month period. Data was analysed in a 2×2 contingency table using Fisher’s exact test. Results: 489 horses were lost to follow-up and 55 horses were excluded, leaving 966 treated and matched, untreated horses. The incidence of laminitis over the 4-month study period in both groups was identical: 3/966 horses (0.31%) (95% C.I. [0.08%, 0.91%]), equivalent to 0.93 cases per 100 horses per year (P >0.9). Main limitations: Retrospective study; large proportion (489/1510) of horses lost to follow-up; large proportion of study population were racehorses; selection method resulted in disproportionate selection of horses born before 2013; similar incidence between groups may reflect existing risk-based selection by clinicians. Conclusions: Intra-synovial triamcinolone acetonide administration does not increase the risk of laminitis in this study population

Dietary nitrate reduces muscle metabolic perturbation and improves exercise tolerance in hypoxia

The definitive version is available at www3.interscience.wiley.comExercise in hypoxia is associated with reduced muscle oxidative function and impaired exercise tolerance. We hypothesised that dietary nitrate supplementation (which increases plasma [nitrite] and thus NO bioavailability) would ameliorate the adverse effects of hypoxia on muscle metabolism and oxidative function. In a double-blind, randomised crossover study, nine healthy subjects completed knee-extension exercise to the limit of tolerance (T(lim)), once in normoxia (20.9% O(2); CON) and twice in hypoxia (14.5% O(2)). During 24 h prior to the hypoxia trials, subjects consumed 0.75 L of nitrate-rich beetroot juice (9.3 mmol nitrate; H-BR) or 0.75 L of nitrate-depleted beetroot juice as a placebo (0.006 mmol nitrate; H-PL). Muscle metabolism was assessed using calibrated (31)P-MRS. Plasma [nitrite] was elevated (P < 0.01) following BR (194 ± 51 nm) compared to PL (129 ± 23 nm) and CON (142 ± 37 nM). T(lim) was reduced in H-PL compared to CON (393 ± 169 vs. 471 ± 200 s; P < 0.05) but was not different between CON and H-BR (477 ± 200 s). The muscle [PCr], [P(i)] and pH changed at a faster rate in H-PL compared to CON and H-BR. The [PCr] recovery time constant was greater (P < 0.01) in H-PL (29 ± 5 s) compared to CON (23 ± 5 s) and H-BR (24 ± 5 s). Nitrate supplementation reduced muscle metabolic perturbation during exercise in hypoxia and restored exercise tolerance and oxidative function to values observed in normoxia. The results suggest that augmenting the nitrate-nitrite-NO pathway may have important therapeutic applications for improving muscle energetics and functional capacity in hypoxia

Measurements of double-helicity asymmetries in inclusive J/ψJ/\psi production in longitudinally polarized p+pp+p collisions at s=510\sqrt{s}=510 GeV

We report the double helicity asymmetry, $A_{LL}^{J/\psi}$, in inclusive $J/\psi$ production at forward rapidity as a function of transverse momentum $p_T$ and rapidity $|y|$. The data analyzed were taken during $\sqrt{s}=510$ GeV longitudinally polarized $p$$+$$p$ collisions at the Relativistic Heavy Ion Collider (RHIC) in the 2013 run using the PHENIX detector. At this collision energy, $J/\psi$ particles are predominantly produced through gluon-gluon scatterings, thus $A_{LL}^{J/\psi}$ is sensitive to the gluon polarization inside the proton. We measured $A_{LL}^{J/\psi}$ by detecting the decay daughter muon pairs $\mu^+ \mu^-$ within the PHENIX muon spectrometers in the rapidity range $1.2<|y|<2.2$. In this kinematic range, we measured the $A_{LL}^{J/\psi}$ to be $0.012 \pm 0.010$~(stat)~$\pm$~$0.003$(syst). The $A_{LL}^{J/\psi}$ can be expressed to be proportional to the product of the gluon polarization distributions at two distinct ranges of Bjorken $x$: one at moderate range $x \approx 0.05$ where recent RHIC data of jet and $\pi^0$ double helicity spin asymmetries have shown evidence for significant gluon polarization, and the other one covering the poorly known small-$x$ region $x \approx 2\times 10^{-3}$. Thus our new results could be used to further constrain the gluon polarization for $x< 0.05$.Comment: 335 authors, 10 pages, 4 figures, 3 tables, 2013 data. Version accepted for publication by Phys. Rev. D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Multiparticle azimuthal correlations for extracting event-by-event elliptic and triangular flow in Au + Au collisions at sNN =200 GeV

We present measurements of elliptic and triangular azimuthal anisotropy of charged particles detected at forward rapidity 1&lt;|η|&lt;3 in Au + Au collisions at sNN=200 GeV, as a function of centrality. The multiparticle cumulant technique is used to obtain the elliptic flow coefficients v2{2},v2{4},v2{6}, and v2{8}, and triangular flow coefficients v3{2} and v3{4}. Using the small-variance limit, we estimate the mean and variance of the event-by-event v2 distribution from v2{2} and v2{4}. In a complementary analysis, we also use a folding procedure to study the distributions of v2 and v3 directly, extracting both the mean and variance. Implications for initial geometrical fluctuations and their translation into the final-state momentum distributions are discussed

Nuclear dependence of the transverse single-spin asymmetry in the production of charged hadrons at forward rapidity in polarized p+pp+p, p+p+Al, and p+p+Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

We report on the nuclear dependence of transverse single-spin asymmetries (TSSAs) in the production of positively-charged hadrons in polarized $p^{\uparrow}+p$, $p^{\uparrow}+$Al and $p^{\uparrow}+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV. The measurements have been performed at forward rapidity ($1.4<\eta<2.4$) over the range of $1.8<p_{T}<7.0$ GeV$/c$ and $0.1<x_{F}<0.2$. We observed a positive asymmetry $A_{N}$ for positively-charged hadrons in \polpp collisions, and a significantly reduced asymmetry in $p^{\uparrow}$+$A$ collisions. These results reveal a nuclear dependence of charged hadron $A_N$ in a regime where perturbative techniques are relevant. These results provide new opportunities to use \polpA collisions as a tool to investigate the rich phenomena behind TSSAs in hadronic collisions and to use TSSA as a new handle in studying small-system collisions.Comment: 303 authors from 66 institutions, 9 pages, 2 figures, 1 table. v1 is version accepted for publication in Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm