Efficiency of low versus high airline pressure in stunning cattle with a pneumatically powered penetrating captive bolt gun

The efficiency of stunning cattle was assessed in 443 animals (304 pure Zebu and 139 crossbred cattle), being mainly mature bulls and cows. Cattle were stunned using a Jarvis pneumatically powered penetrating captive bolt gun operating with low (160–175 psi, N = 82) and high (190 psi, N = 363) airline pressure, which was within the manufactures specifications. Signs of brain function and the position of the shots on the heads were recorded after stunning. Velocity of the captive bolt and its physical parameters were calculated. Cattle shot with low pressures showed more rhythmic respiration (27 vs. 8%, P < 0.001), less tongue protrusion (4 vs. 12%, P = 0.03) and less masseter relaxation (22 vs. 48%, P < 0.001). There was an increased frequency of shots in the ideal position when cattle were shot with the low compared to high airline pressures (15.3 vs. 3.1%). Bolt velocity and its physical parameters were significantly (P < 0.01) higher when using high pressure. Airline pressures below 190 psi are inappropriate when shooting adult Zebu beef cattle with pneumatically powered penetrating captive bolt guns

Ultrasound assessment of the effect of fetal position on supine to prone righting reflex in the guinea pig fetus

The aim of the study was to assess the effect of guinea pig fetal position on the righting reflex from a supine to prone position using ultrasound examination. Experimental and control group were formed, each encompassing 20 pregnant females with 50 fetuses from the 31st to 66th day of gestation. During ultrasound examination, the fetuses from the experimental group were brought into a supine position relative to gravity by placing the dams in the appropriate position. In the control group fetuses were examined for changes in position irrespective of gravity as well as for changes in position after having been brought into a prone position relative to gravity. Comparison of the experimental and the control group showed that experimental group fetuses in the oldest bracket rotated successfully to a prone position more frequently than at other ages. The observed fetal movements indicate that the fetus changes its position using the contact-righting reflex

modCHIMERA: A novel murine closed-head model of moderate traumatic brain injury

AbstractTraumatic brain injury is a major source of global disability and mortality. Preclinical TBI models are a crucial component of therapeutic investigation. We report a tunable, monitored model of murine non-surgical, diffuse closed-head injury—modCHIMERA—characterized by impact as well as linear and rotational acceleration. modCHIMERA is based on the Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA) platform. We tested this model at 2 energy levels: 1.7 and 2.1 Joules—substantially higher than previously reported for this system. Kinematic analysis demonstrated linear acceleration exceeding injury thresholds in humans, although outcome metrics tracked impact energy more closely than kinematic parameters. Acute severity metrics were consistent with a complicated-mild or moderate TBI, a clinical population characterized by high morbidity but potentially reversible pathology. Axonal injury was multifocal and bilateral, neuronal death was detected in the hippocampus, and microglial neuroinflammation was prominent. Acute functional analysis revealed prolonged post-injury unconsciousness, and decreased spontaneous behavior and stimulated neurological scores. Neurobehavioral deficits were demonstrated in spatial learning/memory and socialization at 1-month. The overall injury profile of modCHIMERA corresponds with the range responsible for a substantial portion of TBI-related disability in humans. modCHIMERA should provide a reliable platform for efficient analysis of TBI pathophysiology and testing of treatment modalities.</jats:p

Analysis of basic motor behaviors in quadrupeds

Ability to perform locomotion in different directions and maintain upright body posture is crucial for normal life. At present, mice, which allows employing genetic approaches, are widely used in studying the locomotor system. In these investigations different experimental setups are used to evoke locomotion. First aim of the present study was to compare kinematics of forward (FW) and backward (BW) locomotion performed in different environmental conditions (i.e. in a tunnel, on a treadmill and on an air-ball). On all set-ups, average speed, step amplitude and swing duration during BW locomotion were significantly smaller compared to those observed during FW locomotion. The extent of rostro-caudal paw trajectory in relation to the hip projection to the surface (HP) strongly depended on hip height. With high hip height, the trajectory was symmetrical in relation to HP (middle steps). When hip was low, steps were either displaced rostrally (anterior steps) or caudally (posterior steps) in relation to HP. During FW locomotion, predominantly anterior and posterior steps were observed, respectively, on the treadmill and air-ball, while all three stepping forms were observed in the tunnel. We observed only anterior steps during BW locomotion. Intralimb coordination depended on the form of stepping. Second aim of the present study was to reveal the role of two populations of commissural interneurons (V0V and V0D CINs) in control of a number of basic motor behaviours (BW locomotion, scratching, righting, and postural corrections). For this purpose two types of knockout mice (Vglut2Cre;Dbx1DTA mice and Hoxb8Cre;Dbx1DTA mice with only V0V and all V0 CINs ablated, respectively) as well as wild-type littermates were used. Our results suggest that the functional effect of excitatory V0V CINs during BW locomotion and scratching is inhibitory, and that execution of scratching involves active inhibition of the contralateral scratching CPG mediated by V0V CINs. By contrast, V0D CINs are elements of spinal postural network, generating postural corrections. Finally, both V0D and V0V CINs contribute to generation of righting behavior. Thus, our study shows the differential contribution of V0 neuron subpopulations in generation of diverse motor acts. Single steps in different directions are used for control of balance or body configuration. However, our knowledge about neural mechanisms responsible for their generation is limited. The third aim of the present study was to characterize postural response to disturbance of basic body configuration caused by forward, backward or outward displacement of the hindlimb. In intact rabbits, displacement of the hindlimb in any direction caused a postural response consisting of two components. First, a lateral trunk movement towards the supporting (contralateral) hindlimb was performed, and then a corrective step in the direction opposite to the direction of the initial limb displacement was executed. These two components were generated by different mechanisms activated in a strict order by sensory information from the deviated limb signalling distortion of the limb/limb-trunk configuration. We have shown that the integrity of the forebrain was not critical for generation of this postural response. We proposed a hypothesis about operation of mechanisms generating the postural response characterized in the present study

Changes in TNFα, NFκB and MnSOD protein in the vestibular nuclei after unilateral vestibular deafferentation

BACKGROUND: Unilateral vestibular deafferentation results in strong microglial and astroglial activation in the vestibular nuclei (VN) that could be due to an inflammatory response. This study was aimed at determining if markers of inflammation are upregulated in the VN after chemical unilateral labyrinthectomy (UL) in the rat, and if the inflammatory response, if any, induces the expression of neuroprotective factors that could promote the plasticity mechanisms involved in the vestibular compensation process. The expressions of inflammatory and neuroprotective factors after chemical or mechanical UL were also compared to verify that the inflammatory response was not due to the toxicity of sodium arsanilate. METHODS: Immunohistological investigations combined the labeling of tumor necrosis factor α (TNFα), as a marker of the VN inflammatory response, and of nuclear transcription factor κB (NFκB) and manganese superoxide dismutase (MnSOD), as markers of neuroprotection that could be expressed in the VN because of inflammation. Immunoreactivity (Ir) of the VN cells was quantified in the VN complex of rats. Behavioral investigations were performed to assess the functional recovery process, including both static (support surface) and dynamic (air-righting and landing reflexes) postural tests. RESULTS: Chemical UL (arsanilate transtympanic injection) induced a significant increase in the number of TNFα-Ir cells in the medial and inferior VN on both sides. These changes were detectable as early as 4 h after vestibular lesion, persisted at 1 day, and regained nearly normal values at 3 days. The early increase in TNFα expression was followed by a slightly delayed upregulation of NFκB 8 h after chemical UL, peaking at 1 day, and regaining control values 3 days later. By contrast, upregulation of MnSOD was more strongly delayed (1 day), with a peak at 3 days, and a return to control values at 15 days. Similar changes of TNFα, NFκB, and MnSOD expression were found in rats submitted to mechanical UL. Behavioral observations showed strong posturo-locomotor deficits early after chemical UL (1 day) and a complete functional recovery 6 weeks later. CONCLUSIONS: Our results suggest that the upregulation of inflammatory and neuroprotective factors after vestibular deafferentation in the VN may constitute a favorable neuronal environment for the vestibular compensation process

Changes in TNFα, NFκB and MnSOD protein in the vestibular nuclei after unilateral vestibular deafferentation

<p>Abstract</p> <p>Background</p> <p>Unilateral vestibular deafferentation results in strong microglial and astroglial activation in the vestibular nuclei (VN) that could be due to an inflammatory response. This study was aimed at determining if markers of inflammation are upregulated in the VN after chemical unilateral labyrinthectomy (UL) in the rat, and if the inflammatory response, if any, induces the expression of neuroprotective factors that could promote the plasticity mechanisms involved in the vestibular compensation process. The expressions of inflammatory and neuroprotective factors after chemical or mechanical UL were also compared to verify that the inflammatory response was not due to the toxicity of sodium arsanilate.</p> <p>Methods</p> <p>Immunohistological investigations combined the labeling of tumor necrosis factor α (TNFα), as a marker of the VN inflammatory response, and of nuclear transcription factor κB (NFκB) and manganese superoxide dismutase (MnSOD), as markers of neuroprotection that could be expressed in the VN because of inflammation. Immunoreactivity (Ir) of the VN cells was quantified in the VN complex of rats. Behavioral investigations were performed to assess the functional recovery process, including both static (support surface) and dynamic (air-righting and landing reflexes) postural tests.</p> <p>Results</p> <p>Chemical UL (arsanilate transtympanic injection) induced a significant increase in the number of TNFα-Ir cells in the medial and inferior VN on both sides. These changes were detectable as early as 4 h after vestibular lesion, persisted at 1 day, and regained nearly normal values at 3 days. The early increase in TNFα expression was followed by a slightly delayed upregulation of NFκB 8 h after chemical UL, peaking at 1 day, and regaining control values 3 days later. By contrast, upregulation of MnSOD was more strongly delayed (1 day), with a peak at 3 days, and a return to control values at 15 days. Similar changes of TNFα, NFκB, and MnSOD expression were found in rats submitted to mechanical UL. Behavioral observations showed strong posturo-locomotor deficits early after chemical UL (1 day) and a complete functional recovery 6 weeks later.</p> <p>Conclusions</p> <p>Our results suggest that the upregulation of inflammatory and neuroprotective factors after vestibular deafferentation in the VN may constitute a favorable neuronal environment for the vestibular compensation process.</p

Investigating the Effects of Chronic Amphetamine Treatment on the Midbrain Superior Colliculus

Heightened distractibility, the reduced ability to filter out irrelevant information, is a disruptive symptom found in numerous conditions and healthy ageing. It is most effectively treated with psychostimulant drugs, such as amphetamine, which are given chronically in attention deficit hyperactivity disorder (ADHD). There is converging evidence linking the superior colliculus (SC) to the regulation of distractibility, and acute amphetamine administration is known to suppress collicular responsiveness, however relatively little is known about its mechanism of action and long lasting effects when administered chronically. It is therefore the aim of this thesis to investigate the effects of chronic treatment with amphetamine on the SC, as a neural correlate of distractibility. To achieve this, adolescent Hooded Lister rats were treated orally with amphetamine (2, 5 or 10 mg/kg) or a control (vehicle or untreated) for one month. The effects of treatment were then explored by investigating: collicular-dependant and locomotor behaviour; visual responsiveness of the superficial SC; responses to an acute amphetamine challenge; and the morphology of the superficial SC. At high doses, oral amphetamine treatment resulted in the development of locomotor tolerance, in contrast to previous research using i.p. administration which report sensitisation. Evidence of suppression of activity in the SC was identified from a reduced ability to perform collicular dependant behaviours, and from weaker light responsiveness measured from multi-unit activity in the superficial SC following treatment with high doses of amphetamine. Evidence was also found of a potential compensatory mechanism involving synaptophysin expression and enhanced peri-synaptic activity. This thesis also investigated the types of dendritic spines prevalent in the superficial SC for the first time, and found that these structures were unaffected by amphetamine treatment. These results indicate that the therapeutic effects of amphetamine may stem from suppression of collicular activity, and the SC is susceptible to amphetamine induced remodelling

The Basal Ganglia as a Gate Control Mechanism for Postural Set

Impairment of righting reflexes is one of the cardinal features of basal ganglia disease. Although the precise anatomical organization of these reflexes in man is not fully understood, neurophysiological experiments suggest an important role for the striatum (i.e. caudate nucleus and putamen), pallidum, the supplementary motor area (SMA) and the motor and sensory cortices in righting reactions (see chapter 1-3)

Jumping without Using Legs: The Jump of the Click-Beetles (Elateridae) Is Morphologically Constrained

To return to their feet, inverted click-beetles (Elateridae) jump without using their legs. When a beetle is resting on its dorsal side, a hinge mechanism is locked to store elastic energy in the body and releases it abruptly to launch the beetle into the air. While the functional morphology of the jumping mechanism is well known, the level of control that the beetle has over this jumping technique and the mechanical constraints governing the jumps are not entirely clear. Here we show that while body rotations in air are highly variable, the jumps are morphologically constrained to a constant “takeoff” angle (79.9°±1.56°, n = 9 beetles) that directs 98% of the jumping force vertically against gravity. A physical-mathematical model of the jumping action, combined with measurements from live beetle, imply that the beetle may control the speed at takeoff but not the jumping angle. In addition, the model shows that very subtle changes in the exact point of contact with the ground can explain the vigorous rotations of the body seen while the beetle is airborne. These findings suggest that the evolution of this unique non-legged jumping mechanism resulted in a jumping technique that is capable of launching the body high into the air but it is too constrained and unstable to allow control of body orientation at landing

Modeling subconcussive and cumulative subconcussive impacts using a lateral fluid percusion injury device

Repetitive mTBI and concussion are a major risk factor for developing long-term cognitive and behavioral impairments. Curiously, cumulative head injuries sustained over an individuals’ career, involving contact activities (e.g. athletes and military personnel), are beginning to be implicated in long-term consequences, such as dementia. Recently, chronic traumatic encephalopathy (CTE) has gained momentum in the science and medical community as a neurodegenerative disease of repetitive head injuries. CTE was observed at autopsy of former athletes that did not closely correlate with a clinical history of concussion. Thus, suggesting cumulative subconcussive insults may induce long-term damage. Investigating the etiology of subconcussive and cumulative subconcussive insults clinically is not feasible; however, understanding what correlation exists between cumulative effects of repetitive subconcussive insults is crucial for the medical and scientific community. This study used a lateral fluid percussion injury (lFPI) to model a subconcussive insult; specifically, to test the hypothesis that an initial subconcussive insult will not lead to any significant detectable levels of behavioral or cellular damage, yet cumulative intra-day subconcussive insults will manifest into detectable changes in neuropathology and behavior. This study developed a novel animal model of subconcussive brain injury (scTBI) paradigm and the effects of cumulative intra-day scTBI utilizing a digitally controlled fluid percussion injury device (dcFPI). Acute behavioral effects of cumulative 5x scTBI resulted in longer duration in latency of righting reflex compared to 5x SHAM group. Neuronal degeneration was assessed at 24 h using Fluoro - Jade C, with sparse neuronal degeneration in the granule cell layer of the hippocampus and all 5x scTBI subjects exhibit hemorrhage. Neurobehavior assessment revealed transient suppression of ASR on PID1, returning to SHAM levels by PID4. The presence of immunoreactive microglia and reactive astrocytes was observed in cumulative 5x scTBI at 24 h and 1 w when compared to 5x SHAM group. These findings indicate one scTBI does not result in acute behavior deficits or neuronal degeneration, however cumulative scTBI results transient brainstem dysfunction, blood brain barrier disruption and prolonged neuroinflammation