a b s t r a c tThe food supply chain is affected by losses of products near to their expiry date or damaged by improper transportation or production defects. Such products are usually poorly attractive for the consumer in the target market even if they maintain their nutritional properties. On the other hand undernourished people face every day the problem of fulfilling their nutritional needs usually relying on non-profit organizations. In this field the food recovery enabling economic benefits for donors is nowadays seen as a coherent way to manage food products unsalable in the target market for various causes and thus destined to be discarded and disposed to landfill thus representing only a cost. Despite its obvious affordability the food recovery is today not always practiced because the economic benefits that could be achieved are barely known. The paper aims at presenting a deterministic mathematical model for the optimization of the supply chain composed by retailers and potential recipients that practice the food recovery, taking into account the benefits recognized to donors and the management costs of the food recovery. The model determines the optimal time to withdraw the products from the shelves as well as the quantities to be donated to the non-profit organizations and those to be sent to the livestock market maximizing the retailer profit. The results show that the optimal conditions ensuring the affordability of the food recovery strategy including the tax reliefs and cost saving for the retailers outperforms the profit achievable in absence of such a system.
Many neuropsychiatric symptoms that follow traumatic brain injury (TBI), including mood disorders, sleep disturbance, chronic pain, and posttraumatic epilepsy (PTE) are attributable to compromised cortical inhibition. However, the temporal trajectory of cortical inhibition loss and its underlying mechanisms are not known. Using paired-pulse transcranial magnetic stimulation (ppTMS) and immunohistochemistry, we tracked functional and cellular changes of cortical inhibitory network elements after fluid-percussion injury (FPI) in rats. ppTMS revealed a progressive loss of cortical inhibition as early as 2 weeks after FPI. This profile paralleled the increasing levels of cortical oxidative stress, which was accompanied by a gradual loss of parvalbumin (PV) immunoreactivity in perilesional cortex. Preceding the PV loss, we identified a degradation of the perineuronal net (PNN)-a specialized extracellular structure enwrapping cortical PV-positive (PV+) inhibitory interneurons which binds the PV+ cell maintenance factor, Otx2. The trajectory of these impairments underlies the reduced inhibitory tone, which can contribute to posttraumatic neurological conditions, such as PTE. Taken together, our results highlight the use of ppTMS as a biomarker to track the course of cortical inhibitory dysfunction post-TBI. Moreover, the neuroprotective role of PNNs on PV+ cell function suggests antioxidant treatment or Otx2 enhancement as a promising prophylaxis for post-TBI symptoms.
Repetitive magnetic stimulation (rTMS), including theta burst stimulation (TBS), is capable of modulating motor cortical excitability through plasticity-like mechanisms and might have therapeutic potential for Parkinson's disease (PD). An animal model would be helpful for elucidating the mechanism of rTMS that remain unclear and controversial. Here, we have established a TMS model in rat and applied this model to study the impact of substantia nigra dopamine neuron on TBS-induced motor plasticity in PD rats. In parallel with human results, continuous TBS (cTBS) successfully suppressed motor evoked potentials (MEPs), while MEPs increased after intermittent TBS (iTBS) in healthy rats. We then tested the effect of iTBS in early and advanced 6-hydroxydopamine (6-OHDA)-lesioned PD. Moreover, dopaminergic neurons in substantia nigra and rotation behavior were assessed to correlate with the amount of iTBS-induced plasticity. In results, iTBS-induced potentiation was reduced in early PD rats and was absent in advanced PD rats. Such reduction in plasticity strongly correlated with the dopaminergic cell loss and the count of rotation in PD rats. In conclusion, we have established a TMS PD rat model. With the help of this model, we confirmed the loss of domaninergic neurons in substantia nigra resulting in reduced rTMS-induced motor plasticity in PD.
Background: Epilepsy is a neurological disorder characterized by abnormal neuron discharge, and onethird of epilepsy patients suffer from drug-resistant epilepsy (DRE). The current management for DRE includes epileptogenic lesion resection, disconnection, and neuromodulation. Neuromodulation is achieved through invasive electrical stimulus including deep brain stimulation, vagus nerve stimulation, or responsive neurostimulation (RNS). As an alternative therapy, transcranial focused ultrasound (FUS) can transcranially and non-invasively modulate neuron activity. Objective: This study seeks to verify the use of FUS pulsations to suppress spikes in an acute epileptic small-animal model, and to investigate possible biological mechanisms by which FUS pulsations interfere with epileptic neuronal activity. Methods: The study used a total of 76 Sprague-Dawley rats. For the epilepsy model, rats were administered pentylenetetrazol (PTZ) to induce acute epileptic-like abnormal neuron discharges, followed by FUS exposure. Various ultrasound parameters were set to test the epilepsy-suppressing effect, while concurrently monitoring and analyzing electroencephalogram (EEG) signals. Animal behavior was monitored and histological examinations were conducted to evaluate the hazard posed by ultrasound exposure and the expression of neuronal activity markers. Western blotting was used to evaluate the correlation between FUS-induced epileptic suppression and the PI3K-mTOR signaling pathway. Results: We observed that FUS pulsations effectively suppressed epileptic activity and observed EEG spectrum oscillations; the spike-suppressing effect depended on the selection of ultrasound parameters and highly correlated with FUS exposure level. Expression level changes of c-Fos and GAD65 were confirmed in the cortex and hippocampus, indicating that FUS pulsations deactivated excitatory cells and activated GABAergic terminals. No tissue damage, inflammatory response, or behavioral abnormalities were observed in rats treated with FUS under these exposure parameters. We also found that the FUS pulsations down-regulated the S6 phosphorylation and decreased pAKT expression. Conclusion: Our results suggest that pulsed FUS exposure effectively suppresses epileptic spikes in an acute epilepsy animal model, and finds that ultrasound pulsation interferes with neuronal activity and affects the PTZ-induced PI3K-Akt-mTOR pathway, which might help explain the mechanism underlying ultrasound-related epileptic spike control.
Video-based walking track systems have been developed for gait analysis in rat models. However, there is no previous study using video-based tracking systems to address the gait parameters to evaluate the recovery of Achilles tendon rupture models. This study conducted a comprehensive gait analysis using a video-based image processing system. Eighteen Sprague-Dawley rats were randomly assigned to one of three interventional conditions: sham surgery, Achilles tendon repair, and Achilles tendon defect. After surgery, all animals were evaluated using a video-based walking track system. The gait parameters and the Achilles functional index (AFI) were further analyzed. The ankle joint angles of the injury side at mid-stance and pre-swing were highly correlated with the AFI. However, lack of sensitivity was found for the AFI. Increased measurement sensitivity of the Achilles tendon healing condition was found in the ankle joint angle of the involved side at the pre-swing and the level of asymmetry of the hindlimb joint position and stance/swing time. The overall sensitivity of the ankle motion analysis was significantly higher than that of AFI. We conclude that the ankle motion analysis is a reliable, reproducible, and sensitive tool for Achilles tendon analysis in rats.
Traumatic brain injury (TBI) results in a decrease in glutamate transporter-1 (GLT-1) expression, the major mechanism for glutamate removal from synapses. Coupled with an increase in glutamate release from dead and dying neurons, this causes an increase in extracellular glutamate. The ensuing glutamate excitotoxicity disproportionately damages vulnerable GABAergic parvalbumin-positive inhibitory interneurons, resulting in a progressively worsening cortical excitatory:inhibitory imbalance due to a loss of GABAergic inhibitory tone, as evidenced by chronic post-traumatic symptoms such as epilepsy, and supported by neuropathologic findings. This loss of intracortical inhibition can be measured and followed noninvasively using long-interval paired-pulse transcranial magnetic stimulation with mechanomyography (LI-ppTMS-MMG). Ceftriaxone, a β-lactam antibiotic, is a potent stimulator of the expression of rodent GLT-1 and would presumably decrease excitotoxic damage to GABAergic interneurons. It may thus be a viable antiepileptogenic intervention. Using a rat fluid percussion injury TBI model, we utilized LI-ppTMS-MMG, quantitative PCR, and immunohistochemistry to test whether ceftriaxone treatment preserves intracortical inhibition and cortical parvalbumin-positive inhibitory interneuron function after TBI in rat motor cortex. We show that neocortical GLT-1 gene and protein expression are significantly reduced 1 week after TBI, and this transient loss is mitigated by ceftriaxone. Importantly, whereas intracortical inhibition declines progressively after TBI, 1 week of post-TBI ceftriaxone treatment attenuates the loss of inhibition compared to saline-treated controls. This finding is accompanied by significantly higher parvalbumin gene and protein expression in ceftriaxone-treated injured rats. Our results highlight prospects for ceftriaxone as an intervention after TBI to prevent cortical inhibitory interneuron dysfunction, partly by preserving GLT-1 expression.
ObjectiveTraumatic brain injury (TBI) is a major brain injury type commonly caused by traffic accidents, falls, violence, or sports injuries. To obtain mechanistic insights about TBI, experimental animal models such as weight-drop-induced TBI in rats have been developed to mimic closed-head injury in humans. However, the relationship between the mechanical impact level and neurological severity following weight-drop-induced TBI remains uncertain. In this study, we comprehensively investigated the relationship between physical impact and graded severity at various weight-drop heights.ApproachThe acceleration, impact force, and displacement during the impact were accurately measured using an accelerometer, a pressure sensor, and a high-speed camera, respectively. In addition, the longitudinal changes in neurological deficits and balance function were investigated at 1, 4, and 7 days post TBI lesion. The inflammatory expression markers tested by Western blot analysis, including glial fibrillary acidic protein, beta-amyloid precursor protein, and bone marrow tyrosine kinase gene in chromosome X, in the frontal cortex, hippocampus, and corpus callosum were investigated at 1 and 7 days post-lesion.ResultsGradations in impact pressure produced progressive degrees of injury severity in the neurological score and balance function. Western blot analysis demonstrated that all inflammatory expression markers were increased at 1 and 7 days post-impact injury when compared to the sham control rats. The severity of neurologic dysfunction and induction in inflammatory markers strongly correlated with the graded mechanical impact levels.ConclusionsWe conclude that the weight-drop-induced TBI model can produce graded brain injury and induction of neurobehavioral deficits and may have translational relevance to developing therapeutic strategies for TBI.
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