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Effective management of invasive species requires collaboration across a range of stakeholders. These stakeholders exhibit diverse attributes such as organisation types, operational scale, objectives, and roles within projects. Identifying the diverse attributes of stakeholders is beneficial for increasing collaboration success while minimising potential conflicts among multiple stakeholders when managing invasive species across landscapes. Despite the increasing number of studies on connections among stakeholders, there is little understanding of the diverse attributes of stakeholders involved in invasive species management. This is a notable gap because the diversity of stakeholders is one of the significant factors that can influence collaboration success. To bridge this knowledge gap, we used a social network approach to identify the attributes of stakeholders that influence their participation in collaborations using a case study of invasive wild pig (Sus scrofa) management in Queensland, Australia. Our findings suggest that even though the overall stakeholder network was diverse, the stakeholder network at the project level exhibited a lack of diversity on average, particularly regarding the scale of operation and type of organisation. In other words, stakeholders are highly likely to form ties in projects involving other stakeholders from similar types of organisations or operational scales. We suggest that targeting a greater diversity of stakeholders across types of organisations and scales of operations might enhance the success of collaborative invasive species management.
Subject(s)
Conservation of Natural Resources , Introduced Species , Animals , Queensland , SwineABSTRACT
The negative impacts of climate change on native forest ecosystems have created challenging conditions for the sustainability of natural forest regeneration. These challenges arise primarily from abiotic stresses that affect the early stages of forest tree development. While there is extensive evidence on the diversity of juvenile microbial symbioses in agricultural and fruit crops, there is a notable lack of reports on native forest plants. This review aims to summarize the critical studies conducted on the diversity of juvenile plant-microbe interactions in forest plants and to highlight the main benefits of beneficial microorganisms in overcoming environmental stresses such as drought, high and low temperatures, metal(loid) toxicity, nutrient deficiency, and salinity. The reviewed studies have consistently demonstrated the positive effects of juvenile plant-microbiota interactions and have highlighted the potential beneficial attributes to improve plantlet development. In addition, this review discusses the beneficial attributes of managing juvenile plant-microbiota symbiosis in the context of native forest restoration, including its impact on plant responses to phytopathogens, promotion of nutrient uptake, facilitation of seedling adaptation, resource exchange through shared hyphal networks, stimulation of native soil microbial communities, and modulation of gene and protein expression to enhance adaptation to adverse environmental conditions.
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Invasive species are one of the most pressing global challenges for biodiversity and agriculture. They can cause species extinctions, ecosystem alterations, crop damage, and spread harmful diseases across broad regions. Overcoming this challenge requires collaborative management efforts that span multiple land tenures and jurisdictions. Despite evidence on the importance and approaches to collaboration, there is little understanding of how success is evaluated in the invasive species management literature. This is a major gap, considering evaluating success is crucial for enhancing the efficacy of future management projects. To overcome this knowledge gap, we systematically reviewed the published literature to identify the stages at which success is evaluated - that is, the Process stage (collaborative management actions and Processes), Outputs stage (results of management actions to protect environmental, economic, and social values) and Outcomes stage (effects of Outputs on environmental, economic, and social values) of collaborative invasive species management projects. We also assessed what indicators were used to identify success and whether these evaluations vary across different characteristics of collaborative invasive species management. Our literature search detected 1406 papers, of which 58 met our selection criteria. Out of these, the majority of papers evaluated success across two stages (n = 25, 43.1%), whereas only ten (17.2%) papers evaluated success across all stages. Outputs were the most commonly evaluated stage (n = 40, 68.9%). The most widely used indicators of success for these stages included increased collaboration of stakeholders (Process stage), the number of captured/eradicated/controlled invasive species (Outputs stage) and change in biodiversity values, such as the number of threatened species (Outcomes stage). Most indicators of success were environmentally focused. We highlight the need to align the indicators of success and evaluation stages with the fundamental objectives of the projects to increase the effectiveness of evaluations and thereby maximise the benefits of collaborative invasive species management.
Subject(s)
Ecosystem , Introduced Species , Animals , Biodiversity , Endangered Species , Extinction, BiologicalABSTRACT
Cuban rice cultivars INCA LP-5 and INCA LP-7 are widely distributed in Cuba and Caribbean countries. Although there are studies about rhizospheric bacteria associated with these cultivars, there are no reports about their seed-associated bacteria. This study aimed to isolate endophytic bacteria from rice seeds and select those with the greatest plant growth-promoting traits. A total of nineteen bacterial strains from the genera Pantoea, Bacillus, Paenibacillus, and Pseudomonas were isolated from the husk and endosperm of rice seeds. The strains Pantoea sp. S5-1, Pseudomonas sp. S5-38, and Pseudomonas sp. S7-1 were classified as the most promissory to increase rice growth as they demonstrated the presence of multiple plant growth-promoting traits such as the production of auxins, phosphate, and potassium solubilization, the production of siderophores, and the inhibition of the phytopathogen Pyricularia oryzae. The inoculation of strains of Pantoea sp. and Pseudomonas spp. in rice improves the height, root length, fresh weight, and dry weight of the shoot and root after 21 days post-inoculation in hydroponic assays. This study constitutes the first report on Cuban rice cultivars about the presence of endophytes in seeds and their potential to promote seedling growth. Pantoea sp. S5-1, Pseudomonas sp. S5-38, and Pseudomonas sp. S7-1 were selected as the more promising strains for the development of bio-stimulators or bio-inoculants for Cuban rice crops.
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Significance: The optical measurement of cerebral oxygen metabolism was evaluated. Aim: Compare optically derived cerebral signals to the electroencephalographic bispectral index (BIS) sensors to monitor propofol-induced anesthesia during surgery. Approach: Relative cerebral metabolic rate of oxygen ( rCMRO 2 ) and blood flow (rCBF) were measured by time-resolved and diffuse correlation spectroscopies. Changes were tested against the relative BIS (rBIS) ones. The synchronism in the changes was also assessed by the R-Pearson correlation. Results: In 23 measurements, optically derived signals showed significant changes in agreement with rBIS: during propofol induction, rBIS decreased by 67% [interquartile ranges (IQR) 62% to 71%], rCMRO 2 by 33% (IQR 18% to 46%), and rCBF by 28% (IQR 10% to 37%). During recovery, a significant increase was observed for rBIS (48%, IQR 38% to 55%), rCMRO 2 (29%, IQR 17% to 39%), and rCBF (30%, IQR 10% to 44%). The significance and direction of the changes subject-by-subject were tested: the coupling between the rBIS, rCMRO 2 , and rCBF was witnessed in the majority of the cases (14/18 and 12/18 for rCBF and 19/21 and 13/18 for rCMRO 2 in the initial and final part, respectively). These changes were also correlated in time ( R > 0.69 to R = 1 , p - values < 0.05 ). Conclusions: Optics can reliably monitor rCMRO 2 in such conditions.
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ABSTRACT: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening syndrome, characterized by aberrant activation of T lymphocytes and macrophages leading to hypercytokinemia. HLH can be familial or a result of various secondary etiologies. We present a case of a 46-year-old woman with a past medical history of multiple sclerosis on rituximab who presented as a transfer from an outside hospital with numerous clinical abnormalities including recurrent episodes of fever of unknown origin for 3 weeks, persistent leukocytosis, hypertriglyceridemia, and steatohepatitis. Given the uncertain nature of her illness, she underwent a random skin biopsy from the abdominal region to exclude hematolymphoid malignancy. Histopathology revealed a brisk histiocytic rich dermal infiltrate accompanied by perivascular lymphocytic infiltrate. The histiocytes were enlarged and positive for muraminadase and CD68 stains exhibiting hemophagocytosis focally. As per the HLH-2004 protocol, our patient met the diagnostic criteria of HLH. Concurrent bone marrow biopsy revealed similar rare hemophagocytosis. Cytogenetics and molecular studies were negative, supporting secondary HLH.
Subject(s)
Lymphohistiocytosis, Hemophagocytic , Humans , Female , Middle Aged , Lymphohistiocytosis, Hemophagocytic/pathology , Biopsy , Bone Marrow/pathology , Rituximab , Spleen/pathologyABSTRACT
In precision agriculture (PA) practices, the accurate delineation of management zones (MZs), with each zone having similar characteristics, is essential for map-based variable rate application of farming inputs. However, there is no consensus on an optimal clustering algorithm and the input data format. In this paper, we evaluated the performances of five clustering algorithms including k-means, fuzzy C-means (FCM), hierarchical, mean shift, and density-based spatial clustering of applications with noise (DBSCAN) in different scenarios and assessed the impacts of input data format and feature selection on MZ delineation quality. We used key soil fertility attributes (moisture content (MC), organic carbon (OC), calcium (Ca), cation exchange capacity (CEC), exchangeable potassium (K), magnesium (Mg), sodium (Na), exchangeable phosphorous (P), and pH) collected with an online visible and near-infrared (vis-NIR) spectrometer along with Sentinel2 and yield data of five commercial fields in Belgium. We demonstrated that k-means is the optimal clustering method for MZ delineation, and the input data should be normalized (range normalization). Feature selection was also shown to be positively effective. Furthermore, we proposed an algorithm based on DBSCAN for smoothing the MZs maps to allow smooth actuating during variable rate application by agricultural machinery. Finally, the whole process of MZ delineation was integrated in a clustering and smoothing pipeline (CaSP), which automatically performs the following steps sequentially: (1) range normalization, (2) feature selection based on cross-correlation analysis, (3) k-means clustering, and (4) smoothing. It is recommended to adopt the developed platform for automatic MZ delineation for variable rate applications of farming inputs.
Subject(s)
Remote Sensing Technology , Soil , Algorithms , Cluster Analysis , Spatial AnalysisABSTRACT
Social-ecological networks (SENs) represent the complex relationships between ecological and social systems and are a useful tool for analyzing and managing ecosystem services. However, mainstreaming the application of SENs in ecosystem service research has been hindered by a lack of clarity about how to match research questions to ecosystem service conceptualizations in SEN (i.e., as nodes, links, attributes, or emergent properties). Building from different disciplines, we propose a typology to represent ecosystem service in SENs and identify opportunities and challenges of using SENs in ecosystem service research. Our typology provides guidance for this growing field to improve research design and increase the breadth of questions that can be addressed with SEN to understand human-nature interdependencies in a changing world.
Subject(s)
Conservation of Natural Resources , Ecosystem , HumansABSTRACT
PURPOSE: Spreading depolarization (SD) phenomena are waves of neuronal depolarization, which propagate slowly at a velocity of 1 to 5 mm/minute and can occur in patients with ischemic or hemorrhagic stroke, traumatic brain injury, and migraine with aura. They form part of secondary injury, occurring after spreading ischemia. The purposes of this study were to describe the frequency and characteristics of SD phenomena and to define whether a correlation existed between SD and outcome in a group of patients with TBI and large hemispheric ischemic stroke. METHODS: This was a prospective observational study of 39 adult patients, 17 with malignant middle cerebral artery infarction and 22 with moderate or severe traumatic brain injury, who underwent decompressive craniectomy and multimodal neuromonitoring including electrocorticography. Identification, classification, and interpretation of SDs were performed using the published recommendations from the Cooperative Study on Brain Injury Depolarization group. The outcomes assessed were functional disability at 6 and 12 months after injury, according to the extended Glasgow outcome scale, Barthel index, and modified Rankin scale. RESULTS: Four hundred eighty-three SDs were detected, in 58.9% of the patients. Spreading depolarizations were more common, particularly the isoelectric SD type, in patients with malignant middle cerebral artery infarction (P < 0.04). In 65.21% of patients with SDs on electrocorticography, the "peak" day of depolarization was day 0 (the first 24 hours of recording). Spreading depolarization convulsions were present in 26.08% of patients with SDs. Patients with more SDs and higher depolarization indices scored worse on extended Glasgow outcome scale (6 months) and Barthel index (6 and 12 months) (P < 0.05). CONCLUSIONS: Evidence on SD phenomena is important to ensure continued progress in understanding their pathophysiology, in the search for therapeutic targets to avoid additional damage from these secondary injuries.
Subject(s)
Brain Injuries, Traumatic/physiopathology , Cortical Spreading Depression/physiology , Ischemic Stroke/physiopathology , Recovery of Function/physiology , Adult , Aged , Electrocorticography , Female , Humans , Male , Middle Aged , Prospective StudiesABSTRACT
OBJECTIVE: Spreading depolarizations (SDs) have been described in patients with ischemic and haemorrhagic stroke, traumatic brain injury, and migraine with aura, among other conditions. The exact pathophysiological mechanism of SDs is not yet fully established. Our aim in this study was to evaluate the relationship between the electrocorticography (ECoG) findings of SDs and/or epileptiform activity and subsequent epilepsy and electroclinical outcome. METHODS: This was a prospective observational study of 39 adults, 17 with malignant middle cerebral artery infarction (MMCAI) and 22 with traumatic brain injury, who underwent decompressive craniectomy and multimodal neuromonitoring including ECoG in penumbral tissue. Serial electroencephalography (EEG) recordings were obtained for all surviving patients. Functional disability at 6 and 12 months after injury were assessed using the Barthel, modified Rankin (mRS), and Extended Glasgow Outcome (GOS-E) scales. RESULTS: SDs were recorded in 58.9% of patients, being more common-particularly those of isoelectric type-in patients with MMCAI (p < 0.04). At follow-up, 74.7% of patients had epileptiform abnormalities on EEG and/or seizures. A significant correlation was observed between the degree of preserved brain activity on EEG and disability severity (R [mRS]: + 0.7, R [GOS-E, Barthel]: - 0.6, p < 0.001), and between the presence of multifocal epileptiform abnormalities on EEG and more severe disability on the GOS-E at 6 months (R: - 0.3, p = 0.03) and 12 months (R: - 0.3, p = 0.05). Patients with more SDs and higher depression ratios scored worse on the GOS-E (R: - 0.4 at 6 and 12 months) and Barthel (R: - 0.4 at 6 and 12 months) disability scales (p < 0.05). The number of SDs (p = 0.064) and the depression ratio (p = 0.1) on ECoG did not show a statistically significant correlation with late epilepsy. CONCLUSIONS: SDs are common in the cortex of ischemic or traumatic penumbra. Our study suggests an association between the presence of SDs in the acute phase and worse long-term outcome, although no association with subsequent epilepsy was found. More comprehensive studies, involving ECoG and EEG could help determine their association with epileptogenesis.
Subject(s)
Brain Injuries, Traumatic , Brain Ischemia , Decompressive Craniectomy , Epilepsy , Ischemic Stroke , Stroke , Adult , Brain Injuries, Traumatic/complications , Brain Ischemia/etiology , Decompressive Craniectomy/adverse effects , Epilepsy/surgery , Humans , Prospective Studies , Risk Factors , Treatment OutcomeABSTRACT
As declines in biodiversity accelerate, there is an urgent imperative to ensure that every dollar spent on conservation counts toward species protection. Systematic conservation planning is a widely used approach to achieve this, but there is growing concern that it must better integrate the human social dimensions of conservation to be effective. Yet, fundamental insights about when social data are most critical to inform conservation planning decisions are lacking. To address this problem, we derived novel principles to guide strategic investment in social network information for systematic conservation planning. We considered the common conservation problem of identifying which social actors, in a social network, to engage with to incentivize conservation behavior that maximizes the number of species protected. We used simulations of social networks and species distributed across network nodes to identify the optimal state-dependent strategies and the value of social network information. We did this for a range of motif network structures and species distributions and applied the approach to a small-scale fishery in Kenya. The value of social network information depended strongly on both the distribution of species and social network structure. When species distributions were highly nested (i.e., when species-poor sites are subsets of species-rich sites), the value of social network information was almost always low. This suggests that information on how species are distributed across a network is critical for determining whether to invest in collecting social network data. In contrast, the value of social network information was greatest when social networks were highly centralized. Results for the small-scale fishery were consistent with the simulations. Our results suggest that strategic collection of social network data should be prioritized when species distributions are un-nested and when social networks are likely to be centralized.
Ideas Fundamentales sobre Cuándo Son Más Importantes los Datos de las Redes Sociales para la Planeación de la Conservación Resumen Conforme se aceleran las declinaciones de la biodiversidad, existe una exigencia urgente para asegurar que cada dólar que se gasta en conservación contribuya a la protección de las especies. La planeación sistemática de la conservación es una estrategia usada extensivamente para lograr esto, aunque cada vez existe una mayor preocupación por que integre las dimensiones sociales humanas de la conservación para que sea una estrategia efectiva. Aun así, es insuficiente el conocimiento fundamental sobre cuándo son más importantes los datos sociales para orientar a las decisiones de planeación de la conservación. Para tratar con este problema identificamos los principios novedosos que sirven como guía para la inversión estratégica en la información de las redes sociales para la planeación sistemática de la conservación. Consideramos un problema común para la conservación; identificar con cuáles actores sociales, dentro de una red social, interactuar para incentivar el comportamiento de conservación que maximice el número de especies protegidas. Usamos simuladores de redes sociales y de especies distribuidas a lo largo de nodos de redes para identificar las estrategias dependientes del estado más convenientes y el valor de la información provenientes de las redes sociales. Hicimos lo anterior para una gama de estructuras de redes de motivos y distribución de especies y aplicamos la estrategia a una pesquería a pequeña escala en Kenia. El valor de la información proveniente de las redes sociales depende firmemente tanto de la distribución de las especies como de la estructura de la red social. Cuando las distribuciones de las especies se encontraban extremadamente anidadas (es decir, cuando los sitios pobres en cuanto a cantidad de especies son subconjuntos de sitios ricos en cantidad de especies), el valor de la información proveniente de las redes sociales casi siempre fue bajo. Esto sugiere que la información sobre cómo se distribuyen las especies en una comunidad es crítica para determinar si invertir o no en la recolección de datos provenientes de las redes sociales. Como contraste, el valor de este tipo de información fue mucho mayor cuando las redes sociales estaban sumamente centralizadas. Los resultados de la pesquería a pequeña escala fueron compatibles con las simulaciones. Nuestros resultados sugieren que la recolección estratégica de datos a partir de las redes sociales debería ser prioridad cuando las distribuciones de las especies no se encuentran anidadas y cuando sea probable que las redes sociales estén centralizadas.
Subject(s)
Biodiversity , Conservation of Natural Resources , Humans , Investments , Kenya , Social NetworkingABSTRACT
Introduction: The objective of this study was to compare in vitro the resistance and type of failure in the debonding of lithium disilicate veneers with four different thicknesses using an erbium chromium yttrium-scandium gallium-garnet (Er,Cr:YSGG) laser. Methods: Sixty-eight bovine teeth were used to bond round lithium disilicate veneers with a 6-millimeter diameter and four different thicknesses: group 1 (0.4 mm), group 2 (0.8 mm), group 3 (1.2 mm) and group 4 (1.6 mm). Each sample was irradiated with an Er,Cr:YSGG laser with 4 W of power and a frequency of 50 Hz, during 60 seconds, scanning concentrically. The energy density per pulse or fluency applied was 5.33 J/cm2 for the four groups. The samples were subjected to a force in a universal testing machine and then observed under a microscope to determine the type of failure. Data were statistically analyzed with the non-parametric Kruskal-Wallis test. Results: The tendency in the results revealed that the thicker veneers showed more resistance to the debonding process. The debonding strength for group 3 was the highest (5.62 MPa), followed by group 4 (5.20 MPa), then group 2 (0.85 MPa) and finally group 1 (0.0 MPa). The most frequent type of failure was cohesive failure in cement (CC) for all groups, with 73.53% (P ≤ 0.083). Conclusion: Er,Cr:YSGG laser irradiation influences the debonding of lithium disilicate veneers with different thicknesses: the smaller thickness showed the greater debonding. The thickness of veneers was not associated with the type of failure.
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Lysosomal acidification is a key feature of healthy cells. Inability to maintain lysosomal acidic pH is associated with aging and neurodegenerative diseases. However, the mechanisms elicited by impaired lysosomal acidification remain poorly understood. We show here that inhibition of lysosomal acidification triggers cellular iron deficiency, which results in impaired mitochondrial function and non-apoptotic cell death. These effects are recovered by supplying iron via a lysosome-independent pathway. Notably, iron deficiency is sufficient to trigger inflammatory signaling in cultured primary neurons. Using a mouse model of impaired lysosomal acidification, we observed a robust iron deficiency response in the brain, verified by in vivo magnetic resonance imaging. Furthermore, the brains of these mice present a pervasive inflammatory signature associated with instability of mitochondrial DNA (mtDNA), both corrected by supplementation of the mice diet with iron. Our results highlight a novel mechanism linking impaired lysosomal acidification, mitochondrial malfunction and inflammation in vivo.
Subject(s)
Acids/metabolism , Inflammation/metabolism , Inflammation/pathology , Iron Deficiencies , Lysosomes/metabolism , Animals , Apoptosis , Brain/metabolism , Cell Hypoxia/drug effects , Cell Proliferation , DNA, Mitochondrial/genetics , Disease Models, Animal , Electron Transport , Enzyme Inhibitors/pharmacology , Gene Expression Regulation/drug effects , Homeostasis , Hydrogen-Ion Concentration , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Immunity, Innate , Inflammation/genetics , Iron/pharmacology , Lysosomes/drug effects , Mice , Mitochondria/metabolism , Organelle Biogenesis , Vacuolar Proton-Translocating ATPases/antagonists & inhibitors , Vacuolar Proton-Translocating ATPases/metabolism , alpha-Glucosidases/deficiency , alpha-Glucosidases/metabolismABSTRACT
Conservation conflict is widespread, damaging, and has proved difficult to manage using conventional conservation approaches. Conflicts are often "wicked problems," lacking clear solutions due to divergent values of stakeholders, and being embedded within wickedly complex environments. Drawing on the concept of wicked environmental problems could lead to management strategies better suited to tackling conflict. However, it is unclear whether managers are embracing ideas from the wicked problems concept. There is currently a lack of guidance for applying strategies to tackle particular wicked problems, such as conservation conflict. We explored the suitability of wicked problems-inspired management, using eight contemporary conflict case studies. Conservation conflict was managed predominantly using conventional approaches suited to tackling single objectives in simple environments, rather than balancing competing objectives in complex environments. To deal with different characteristics of wickedness, we recommend that managers develop strategies combining distributed decision-making, diverse opinions, pattern-based predictions, trade-off-based objectives, and reporting of failures. Recent advances in conservation conflict research have focused on improving interactions among stakeholders. We believe that such stakeholder-focused approaches would dovetail with the whole-system focus of a wicked problems framework, allowing conservationists to move toward a holistic strategy for managing conservation conflict.
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Significant controversy exists regarding the potential clinical benefit of normobaric hyperoxia (NBO) in patients with traumatic brain injury (TBI). This study consisted of two aims: 1) to assess whether NBO improves brain oxygenation and metabolism and 2) to determine whether this therapy may increase the risk of oxidative stress (OxS), using 8-iso-Prostaglandin F2α (PGF2α) as a biomarker. Thirty-one patients with a median admission Glasgow Coma Scale score of 4 (min: 3, max: 12) were monitored with cerebral microdialysis and brain tissue oxygen sensors and treated with fraction of inspired oxygen (FiO2) of 1.0 for 4 h. Patients were divided into two groups according to the area monitored by the probes: normal injured brain and traumatic penumbra/traumatic core. NBO maintained for 4 h did not induce OxS in patients without preOxS at baseline, except in one case. However, for patients in whom OxS was detected at baseline, NBO induced a significant increase in 8-iso-PGF2α. The results of our study showed that NBO did not change energy metabolism in the whole group of patients. In the five patients with brain lactate concentration ([Lac]brain) > 3.5 mmol/L at baseline, NBO induced a marked reduction in both [Lac]brain and lactate-to-pyruvate ratio. Although these differences were not statistically significant, together with the results of our previous study, they suggest that TBI patients would benefit from receiving NBO when they show indications of disturbed brain metabolism. These findings, in combination with increasing evidence that TBI metabolic crises are common without brain ischemia, open new possibilities for the use of this accessible therapeutic strategy in TBI patients.
Subject(s)
Brain Injuries, Traumatic/therapy , Dinoprost/analogs & derivatives , Hyperbaric Oxygenation/adverse effects , Oxidative Stress , Adolescent , Adult , Biomarkers/analysis , Dinoprost/analysis , Female , Humans , Hyperoxia/complications , Male , Microdialysis , Middle Aged , Young AdultABSTRACT
BACKGROUND AND PURPOSE: Interspecies variability and poor clinical translation from rodent studies indicate that large gyrencephalic animal stroke models are urgently needed. We present a proof-of-principle study describing an alternative animal model of malignant infarction of the middle cerebral artery (MCA) in the common pig and illustrate some of its potential applications. We report on metabolic patterns, ionic profile, brain partial pressure of oxygen (PtiO2), expression of sulfonylurea receptor 1 (SUR1), and the transient receptor potential melastatin 4 (TRPM4). METHODS: A 5-hour ischemic infarct of the MCA territory was performed in 5 2.5-to-3-month-old female hybrid pigs (Large White x Landrace) using a frontotemporal approach. The core and penumbra areas were intraoperatively monitored to determine the metabolic and ionic profiles. To determine the infarct volume, 2,3,5-triphenyltetrazolium chloride staining and immunohistochemistry analysis was performed to determine SUR1 and TRPM4 expression. RESULTS: PtiO2 monitoring showed an abrupt reduction in values close to 0 mmHg after MCA occlusion in the core area. Hourly cerebral microdialysis showed that the infarcted tissue was characterized by reduced concentrations of glucose (0.03 mM) and pyruvate (0.003 mM) and increases in lactate levels (8.87mM), lactate-pyruvate ratio (4202), glycerol levels (588 µM), and potassium concentration (27.9 mmol/L). Immunohistochemical analysis showed increased expression of SUR1-TRPM4 channels. CONCLUSIONS: The aim of the present proof-of-principle study was to document the feasibility of a large animal model of malignant MCA infarction by performing transcranial occlusion of the MCA in the common pig, as an alternative to lisencephalic animals. This model may be useful for detailed studies of cerebral ischemia mechanisms and the development of neuroprotective strategies.
Subject(s)
Brain/pathology , Disease Models, Animal , Infarction, Middle Cerebral Artery/pathology , Middle Cerebral Artery/pathology , Animals , Brain/blood supply , Brain/metabolism , Female , Gene Expression , Glucose/metabolism , Glycerol/metabolism , Immunohistochemistry , Infarction, Middle Cerebral Artery/diagnosis , Infarction, Middle Cerebral Artery/genetics , Infarction, Middle Cerebral Artery/metabolism , Lactic Acid/metabolism , Middle Cerebral Artery/metabolism , Oximetry , Oxygen/metabolism , Partial Pressure , Potassium/metabolism , Pyruvic Acid/metabolism , Sulfonylurea Receptors/genetics , Sulfonylurea Receptors/metabolism , TRPM Cation Channels/genetics , TRPM Cation Channels/metabolismABSTRACT
Traumatic brain injury (TBI) and ischemic stroke cause a variable disruption of ionic homeostasis and massive ionic fluxes with subsequent osmotic water movement across the cells that causes edema, brain swelling, and deformation of the damaged tissue. Although cerebral microdialysis (CMD) has been used to study the brain neurochemistry, the ionic profiles of brain interstitial space fluid have rarely been reported in humans. We studied the ionic profile in injured areas of the brain by using CMD. As a control group, we included seven patients who had undergone surgical treatment of posterior fossa lesions, without abnormalities in the supratentorial compartment. Inductively coupled plasma mass spectrometry (ICP-MS) was used for ion determination. No significant differences were found in the [Na+]o, [K+]o, and [Cl-]o between normal injured brains and controls. The ionic profile of the ischemic core was characterized by very high [K+]o and an increase in [Na+]o, whereas [Cl-]o was linearly related to [Na+]o. In the traumatic core (TC), significantly higher levels of [Na+]o, [Cl-]o, and [K+]o were found. The main finding in the penumbra was a completely normal ionic profile for [Na+]o and [K+]o in 60% of the samples. ICP-MS coupled to ionic assays creates a powerful tool for a better understanding of the complex ionic disturbances that occur after severe TBI and ischemic stroke.