Three-dimensional kinematic gait analysis of Doberman Pinschers with and without cervical spondylomyelopathy

BACKGROUND

The optimal treatment of cervical spondylomyelopathy (CSM) is controversial, with the owner's and clinician's perception of gait improvement often being used as outcome measures. These methods are subjective and suffer from observer bias.

OBJECTIVES

To establish kinematic gait parameters utilizing digital motion capture in normal Doberman Pinschers and compare them with CSM-affected Dobermans.

ANIMALS

Nineteen Doberman Pinschers; 10 clinically normal and 9 with CSM.

METHODS

All dogs were enrolled prospectively and fitted with a Lycra(®) body suit, and motion capture was performed and used to reconstruct a 3-D stick diagram representation of each dog based on 32 reflective markers, from which several parameters were measured. These included stride duration, length, and height; maximal and minimal spinal angles; elbow and stifle flexion and extension; and maximum and minimum distances between the thoracic and pelvic limbs. A random-effects linear regression model was used to compare parameters between groups.

RESULTS

Significant differences between groups included smaller minimum (mean = 116 mm; P = .024) and maximum (mean = 184 mm; P = .001) distance between the thoracic limbs in CSM-affected dogs. Additionally, thoracic limb stride duration was also smaller (P = .009) in CSM-affected dogs (mean = 0.7 seconds) when compared with normal dogs (mean = 0.8 seconds). In the pelvic limbs, the average stifle flexion (mean = 100°; P = .048) and extension (mean = 136°; P = .009), as well as number of strides (mean = 2.7 strides; P = .033) were different between groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our findings suggest that computerized gait analysis reveals more consistent kinematic differences in the thoracic limbs, which can be used as future objective outcome measures.

Mood congruent psychotic symptoms and specific cognitive deficits in carriers of the novel schizophrenia risk variant at MIR-137

OBJECTIVE

The Schizophrenia Psychiatric Genome-wide Association (GWAS) Consortium recently reported on five novel schizophrenia susceptibility loci. The most significant finding mapped to a micro-RNA, MIR-137, which may be involved in regulating the function of other schizophrenia and bipolar disorder susceptibility genes.

METHOD

We genotyped 821 patients with confirmed DSM-IV diagnoses of schizophrenia, bipolar affective disorder I and schizoaffective disorder for the risk SNP (rs1625579) and investigated the clinical profiles of risk allele carriers using a within-case design. We also assessed neurocognitive performance in a subset of cases (n=399) and controls (n=171).

RESULTS

Carriers of the risk allele had lower scores for an OPCRIT-derived positive symptom factor (p=0.04) and lower scores on a lifetime measure of psychosis incongruity (p=0.017). Risk allele carriers also had more cognitive deficits involving episodic memory and attentional control.

CONCLUSION

This is the first evidence that the MIR-137 risk variant may be associated with a specific subgroup of psychosis patients. Although the effect of this single SNP was not clinically relevant, investigation of the impact of carrying multiple risk SNPs in the MIR-137 regulatory network on diagnosis and illness profile may be warranted.

Caspase-2 deficiency promotes aberrant DNA-damage response and genetic instability

Caspase-2 is an initiator caspase, which has been implicated to function in apoptotic and non-apoptotic signalling pathways, including cell-cycle regulation, DNA-damage signalling and tumour suppression. We previously demonstrated that caspase-2 deficiency enhances E1A/Ras oncogene-induced cell transformation and augments lymphomagenesis in the EμMyc mouse model. Caspase-2(-/-) mouse embryonic fibroblasts (casp2(-/-) MEFs) show aberrant cell-cycle checkpoint regulation and a defective apoptotic response following DNA damage. Disruption of cell-cycle checkpoints often leads to genomic instability (GIN), which is a common phenotype of cancer cells and can contribute to cellular transformation. Here we show that caspase-2 deficiency results in increased DNA damage and GIN in proliferating cells. Casp2(-/-) MEFs readily escape senescence in culture and exhibit increased micronuclei formation and sustained DNA damage during cell culture and following γ-irradiation. Metaphase analyses demonstrated that a lack of caspase-2 is associated with increased aneuploidy in both MEFs and in EμMyc lymphoma cells. In addition, casp2(-/-) MEFs and lymphoma cells exhibit significantly decreased telomere length. We also noted that loss of caspase-2 leads to defective p53-mediated signalling and decreased trans-activation of p53 target genes upon DNA damage. Our findings suggest that loss of caspase-2 serves as a key function in maintaining genomic integrity, during cell proliferation and following DNA damage.

Optimizing a beef production system using specialized sire and dam lines

Tang, G., Stewart-Smith, J., Plastow, G., Moore, S., Basarab, J., MacNeil, M. D. and Wang, Z. 2011. Optimizing a beef production system using specialized sire and dam lines. Can. J. Anim. Sci. 91: 353–361. Crossbreeding is an effective method for improving the efficiency of production in commercial cow-calf operations. It exploits available heterosis (hybrid vigour) and complementarity between different breeds or populations (lines). Before adopting a crossbreeding system, commercial cattle producers should evaluate available genetic resources and feasible crossbreeding systems, and choose one that is most beneficial for their own environment, resources, and management. This study compared profitability of alternative crossbreeding systems based on Beefbooster beef cattle breeding strains through computer simulation. Biological and economic data were collected from commercial customers of Beefbooster in Montana and western Canada, and breeding records from the database of Beefbooster, Inc. Three maternal strains (M1, M2 and M4) and two specialized paternal strains (M3 and TX), were evaluated with two simulated crossbreeding systems. System 1 uses a rotational cross between M1 and M4 with yearling crossbred heifers bred to M3 sires. System 2 is based on a three-strain rotation of M1, M2 and M4 with yearling crossbred heifers bred to M3 to facilitate ease of calving and crossbred cows bred to a classical terminal sire strain TX. Simulated base profit from system 2 was $29.57 greater ($215.21 vs. $185.64 yr−1 per cow) than from system 1.

Physical activity intensity but not sedentary activity is reduced in chronic fatigue syndrome and is associated with autonomic regulation

BACKGROUND

Chronic fatigue syndrome (CFS) is a common debilitating condition associated with reduced function and impaired quality of life. The cause is unknown and treatments limited. Studies confirm that CFS is associated with impaired autonomic regulation and impaired muscle function.

AIM

Define the relationship between sedentary behaviour, physical activity and autonomic regulation in people with CFS.

DESIGN

Cohort study.

METHODS

Physical activity was assessed objectively in 107 CFS patients (Fukuda) and age, sex and body mass index (BMI)-matched sedentary controls (n= 107). Fatigue severity was determined using the Fatigue Impact Scale in all participants and heart rate variability performed in the CFS group.

RESULTS

The CFS group had levels and patterns of sedentary behaviour similar to non-fatigue controls (P > 0.05). Seventy-nine percent of the CFS group did not achieve the WHO recommended 10,000 steps per day. Active energy expenditure [time >3 METs (metabolic equivalents)] was reduced in CFS when compared with controls (P < 0.0001). Physical activity duration was inversely associated with resting heart rate (P = 0.04; r(2) = 0.03), with reduced activity significantly associating with reduced heart rate variability in CFS. There were no relationships between fatigue severity and any parameter of activity. Thirty-seven percent of the CFS group were overweight (BMI 25-29.9) and 20% obese (BMI ≥ 30).

CONCLUSION

Low levels of physical activity reported in CFS represent a significant and potentially modifiable perpetuating factor in CFS and are not attributable to high levels of sedentary activity, rather a decrease in physical activity intensity. The reduction in physical activity can in part be explained by autonomic dysfunction but not fatigue severity.