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Dogs are often housed alone in shelter settings to reduce injury and disease spread. However, social isolation can be a stressor for dogs. Prior studies have suggested that cohousing can produce behavioral and physiological benefits. These studies have typically focused on laboratory dogs or shelter dogs that have been kenneled for several months. Thus, those results might not necessarily generalize to shelter dogs, many of which have shorter lengths of stay than those dogs studied to date, and might be cohoused soon after intake. In fact, being pair-housed could, in the short term, be more stressful as dogs have to navigate novel social situations in small spaces. We investigated the behavioral and physiological effects of single- or pair-housing shelter dogs, most of which had recently entered the shelter. We collected behavioral data on 61 dogs (30 single-housed; 31 pair-housed) daily across seven days; we also collected urine for cortisol:creatinine analysis on a subset (22 single-housed; 18 pair-housed) for eight days (each day of the seven-day study plus a baseline sample on Day 0, prior to dogs' enrollment). We found pair-housed dogs engaged in three stress-related behaviors (lip licking, whining, and ears back) significantly less frequently than single-housed dogs. When we analyzed the change in urinary cortisol:creatinine (Days 1-7 values minus Day 0 value), we found that pair-housed dogs generally showed a greater decrease in cortisol:creatinine levels than single-housed dogs. Pair-housed dogs also had significantly shorter lengths of stay, but we did not detect any effect on dog-dog skills. Overall, we found well-matched pair-housing can have both proximate and ultimate welfare benefits for shelter dogs., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Hecker et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: Our aim is to validate the process steps implemented by the French CATI platform to assess amyloid status, obtained from 18F-Florbetapir PET scans, in a cohort of 318 cognitively normal subjects participating in the INSIGHT-preAD study. Our objective was to develop a method with partial volume effect correction (PVEC) on untransformed PET images, using an automated pipeline ("RACHEL") adapted to large series of patients and including quality checks of results., Methods: We compared RACHEL using different options (with and without PVEC, different sets of regions of interest), to two other methods validated in the literature, referred as the "AVID" and "CAEN" methods. A standard uptake value ratio (SUVR) was obtained with the different methods for participants to another French study, IMAP, including 26 normal elderly controls (NEC), 11 patients with mild cognitive impairment (MCI) and 16 patients with Alzheimer's disease (AD). We determined two cutoffs for RACHEL method by linear correlation with the other methods and applied them to the INSIGHT-preAD subjects., Results: RACHEL including PVEC and a combination of the whole cerebellum and the pons as a reference region allowed the best discrimination between NEC and AD participants. A strong linear correlation was found between RACHEL and the other two methods and yielded the two cutoffs of 0.79 and 0.88. According to the more conservative threshold, 19.8% of the INSIGHT-preAD subjects would be considered amyloid positive, and 27.7% according to the more liberal threshold., Conclusions: With our method, we clearly discriminated between NEC with negative amyloid status and patients with clinical AD. Using a linear correlation with other validated cutoffs, we could infer our own positivity thresholds and apply them to an independent population. This method might be useful to the community, especially when the optimal cutoff could not be obtained from a population of healthy young adults or from correlation with post-mortem results.

The purpose of this study was to determine whether exercise and/or acetaminophen (APAP) alter collagen and cross-linking in the rat gastrocnemius muscle, soleus muscle, and heart. Male Wistar rats (n = 50; 8 wk old) were divided into placebo (PLA) or APAP groups and sedentary (SED) or exercised (RUN) groups. APAP (200 mg/kg) was administered daily by oral gavage. Exercised groups ran on a treadmill 5 days/wk for 8 wk with progression to 60 min/day, 20 m/min, and 8° incline. Tissues were assayed for collagen (hydroxyproline) and hydroxylyslpyridinoline (HP) and lysylpyridinoline (LP) cross-links by HPLC. Collagen content (μg/mg dry weight) was greater in both the gastrocnemius (SED-PLA: 114 ± 16 vs., Run-Pla: 244 ± 32; P < 0.001) and soleus (SED-PLA: 51 ± 7 vs., Run-Pla: 99 ± 27; P = 0.005) of exercised animals. In contrast, collagen content was not significantly greater in exercised animals treated with APAP (SED-APAP: 113 ± 16 vs., Run-Apap: 145 ± 21) and soleus (SED-APAP: 55 ± 8 vs., Run-Apap: 57 ± 10). HP cross-linking (mmol/mol collagen) in the gastrocnemius (SED-PLA: 126 ± 28, RUN-PLA: 50 ± 7, SED-APAP: 41 ± 7, and, Run-Apap: 30 ± 4) and soleus muscles (SED-PLA: 547 ± 107, RUN-PLA: 318 ± 92, SED-APAP: 247 ± 64, and, Run-Apap: 120 ± 17) was lower in exercised rats compared with sedentary rats (P < 0.05). Cross-linking was further reduced in animals treated with APAP (P < 0.05). Neither heart collagen nor cross-linking was influenced by exercise or APAP (P > 0.05). Our findings suggest that exercise and APAP have tissue-specific effects on muscle collagen. Given the widespread use of APAP as an analgesic and antipyretic, further work in humans is warranted., (Copyright © 2015 the American Physiological Society.)