NEXMIF/KIDLIA Knock-out Mouse Demonstrates Autism-Like Behaviors, Memory Deficits, and Impairments in Synapse Formation and Function.

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disability that demonstrates impaired social interactions, communication deficits, and restrictive and repetitive behaviors. ASD has a strong genetic basis and many ASD-associated genes have been discovered thus far. Our previous work has shown that loss of expression of the X-linked gene NEXMIF/KIDLIA is implicated in patients with autistic features and intellectual disability (ID). To further determine the causal role of the gene in the disorder, and to understand the cellular and molecular mechanisms underlying the pathology, we have generated a NEXMIF knock-out (KO) mouse. We find that male NEXMIF KO mice demonstrate reduced sociability and communication, elevated repetitive grooming behavior, and deficits in learning and memory. Loss of NEXMIF/KIDLIA expression results in a significant decrease in synapse density and synaptic protein expression. Consistently, male KO animals show aberrant synaptic function as measured by excitatory miniatures and postsynaptic currents in the hippocampus. These findings indicate that NEXMIF KO mice recapitulate the phenotypes of the human disorder. The NEXMIF KO mouse model will be a valuable tool for studying the complex mechanisms involved in ASD and for the development of novel therapeutics for this disorder.SIGNIFICANCE STATEMENT Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by behavioral phenotypes. Based on our previous work, which indicated the loss of NEXMIF/KIDLIA was associated with ASD, we generated NEXMIF knock-out (KO) mice. The NEXMIF KO mice demonstrate autism-like behaviors including deficits in social interaction, increased repetitive self-grooming, and impairments in communication and in learning and memory. The KO neurons show reduced synapse density and a suppression in synaptic transmission, indicating a role for NEXMIF in regulating synapse development and function. The NEXMIF KO mouse faithfully recapitulates the human disorder, and thus serves as an animal model for future investigation of the NEXMIF-dependent neurodevelopmental disorders.

Effects of distance from canal and degradation history on peat bulk density in a degraded tropical peatland.

Over recent decades, the combination of deforestation, peat drainage and fires have resulted in widespread degradation of Southeast Asia's tropical peatlands. These disturbances are generally thought to increase peat soil bulk density through peat drying and shrinkage, compaction, and consolidation. Biological oxidation and fires burning across these landscapes also consume surface peat, exposing older peat strata. The prevalence and severity of deforestation, peat drainage and fire are typically greater closer to canals, built to drain peatlands and provide access routes for people. We compared bulk densities of 240cm peat profiles from intact forests and degraded peatlands broadly, and also assessed differences between degraded peatlands near-to-canals (50-200m from the nearest canal) and far-from-canals (300+ m from the nearest canal). The effects of vegetation type and fire frequency on bulk density, irrespective of the distance from canal, were also investigated. Mean bulk density values ranged between 0.08 and 0.16gcm-3 throughout the 240cm peat profiles. Drainage of peat near-to-canals increased bulk density of peat above the minimum water table depth. Degradation by deforestation and fire also increased bulk densities of upper peat strata, albeit with greater variability. Peat sampled further from canals experienced less intense water table drawdowns, buffering them from drainage effects. These areas were also more commonly forested and burnt less frequently. Differences in bulk densities below minimum water table levels are less clear, but may reflect lowering of the current peat surface in degraded peatlands broadly. These results clearly show that important differences in bulk density exist across degraded peatlands that are spatially dependent on distance from canals and disturbance history. These landscape features should be taken into account when designing future bulk density sampling efforts and peatland restoration programs, or when extrapolating from existing sources in order to make accurate inferences from them.

Analysis of 10 years of injury in high school rodeo.

OBJECTIVE: To determine the injury rate of athletes participating in high school rodeo. DESIGN: Retrospective report review. SETTING: National High School rodeo finals from 1996 to 2005. PARTICIPANTS: High school athletes qualified for the rodeo competitions through state or national qualifying rounds. ASSESSMENT OF RISK FACTORS: Injury reports were documented by sports medicine personnel. Variables evaluated were injury density, frequency for mechanism of injury, injury location, injury type, and follow-up request. RESULTS: A total of 354 injury incidents from 43,168 competitor exposures (CEs) resulted in a composite injury density of 8.20 per 1000 CE. Rough stock athletes accounted for 76.6% of all injuries. Bareback riders, followed by bull riders and saddle bronc riders, demonstrated injury densities of 31.9, 28.5, and 23.5 per 1000 CE, respectively. Most injuries (40.9%) were sustained while dismounting or being bucked off of the animal. Contusions, sprains, and strains were the most frequent injury types (27.4%, 18.6%, and 16.4%, respectively). The head and the shoulder (17.8% and 11.35%, respectively) were the most commonly injured body parts. An incidence density of 0.7 per 1000 CE was found for injury requiring transport by ambulance. CONCLUSIONS: High school rodeo athletes sustain similar injuries to collegiate and professional rodeo athletes, indicating that addressing issues at the youth level may be of great benefit. To better provide prevention tools for rodeo athletes, mechanism of injury and methods to reduce buck-off need further inquiry.

Physical activity and its relationship to rodeo injury and success.

The purpose of this study was to determine the interrelationship among physical activity, injury, and success of rodeo athletes. Seventy-two male Professional Rodeo Cowboys' Association members served as participants and were grouped into timed, steer-wrestling, saddle-bronc, bareback, bull-riding, and multiple rough-stock events. Participants completed demographic and overall physical activity questionnaires. Sixty-two percent of the subjects participated in regular exercise for a minimum of 2 days per week. Pearson bivariate correlation coefficients revealed weak correlations (r = 0.151, -0.188, and -0.074; p > 0.05) among metabolic (MET) level, earnings rate, and injury rate. A 1-way between-subjects analysis of variance indicated no differences in MET level among groups. Physical activity did not affect performance or injury rate, and competitors in various events did not have different levels of energy expenditure. Therefore, rodeo sports-medicine personnel should encourage athletes to engage in other sport-specific training activities to help prevent rodeo injuries.