The study of intercalated cells using ex vivo techniques: primary cell culture, cell lines, kidney slices, and organoids.

This review summarizes methods to study kidney intercalated cell (IC) function ex vivo. While important for acid-base homeostasis, IC dysfunction is often not recognized clinically until it becomes severe. The advantage of using ex vivo techniques is that they allow for the differential evaluation of IC function in controlled environments. Although in vitro kidney tubular perfusion is a classical ex vivo technique to study IC, here we concentrate on primary cell cultures, immortalized cell lines, and ex vivo kidney slices. Ex vivo techniques are useful in evaluating IC signaling pathways that allow rapid responses to extracellular changes in pH, CO2, and bicarbonate (HCO3-). However, these methods for IC work can also be challenging, as cell lines that recapitulate IC do not proliferate easily in culture. Moreover, a "pure" IC population in culture does not necessarily replicate its collecting duct (CD) environment, where ICs are surrounded by the more abundant principal cells (PCs). It is reassuring that many findings obtained in ex vivo IC systems signaling have been largely confirmed in vivo. Some of these newly identified signaling pathways reveal that ICs are important for regulating NaCl reabsorption, thus suggesting new frontiers to target antihypertensive treatments. Moreover, recent single-cell characterization studies of kidney epithelial cells revealed a dual developmental origin of IC, as well as the presence of novel CD cell types with certain IC characteristics. These exciting findings present new opportunities for the study of IC ex vivo and will likely rediscover the importance of available tools in this field.NEW & NOTEWORTHY The study of kidney intercalated cells has been limited by current cell culture and kidney tissue isolation techniques. This review is to be used as a reference to select ex vivo techniques to study intercalated cells. We focused on the use of cell lines and kidney slices as potential useful models to study membrane transport proteins. We also review how novel collecting duct organoids may help better elucidate the role of these intriguing cells.

Evaluation of comprehensiveness and reliability of electronic health records concerning resuscitation efforts within academic intensive care units: a retrospective chart analysis.

BACKGROUND: According to the literature, the validity and reliability of medical documentation concerning episodes of cardiopulmonary resuscitation (CPR) is suboptimal. However, little is known about documentation quality of CPR efforts during intensive care unit (ICU) stays in electronic patient data management systems (PDMS). This study analyses the reliability of CPR-related medical documentation within the ICU PDMS. METHODS: In a retrospective chart analysis, PDMS records of three ICUs of a single university hospital were searched over 5 y for CPR check marks. Respective datasets were analyzed concerning data completeness and data consistency by comparing the content of three documentation forms (physicians' log, nurses' log, and CPR incident form), as well as physiological and therapeutic information of individual cases, for missing data and plausibility of CPR starting time and duration. To compare data reliability and completeness, a quantitative measure, the Consentaneity Index (CI), is proposed. RESULTS: One hundred sixty-five datasets were included into the study. In 9% (n = 15) of cases, there was neither information on the time points of CPR initiation nor on CPR duration available in any data source. Data on CPR starting time and duration were available from at least two data sources in individual cases in 54% (n = 90) and 45% (n = 74), respectively. In these cases, the specifications of CPR starting time did differ by a median ± interquartile range of 10.0 ± 18.5 min, CPR duration by 5.0 ± 17.3 min. The CI as a marker of data reliability revealed a low consistency of CPR documentation in most cases, with more favorable results, if the time interval between the CPR episode and the time of documentation was short. CONCLUSIONS: This study reveals relevant proportions of missing and inconsistent data in electronic CPR documentation in the ICU setting. The CI is suggested as a tool for documentation quality analysis and monitoring of improvements.

[The disaster task force medical officer as a pivotal decision maker in the superordinate pandemic hospital capacity management : A field report covering the initial COVID-19 surge in a Bavarian district]. / Der Ärztliche Leiter Führungsgruppe Katastrophenschutz als zentrale Entscheidungsinstanz bei der Steuerung regionaler Krankenhauskapazitäten in der Pandemie : Ein Erfahrungsbericht zur ersten Welle der COVID-19-Pandemie in einem bayerischen Regierungsbezirk.

BACKGROUND AND OBJECTIVE: During the initial phase of the COVID-19 pandemic the government of the state of Bavaria, Germany, declared a state of emergency for its entire territory for the first time in history. Some areas in eastern Bavaria were among the most severely affected communities in Germany, prompting authorities and hospitals to build up capacities for a surge of COVID-19 patients. In some areas, intensive care unit (ICU) capacities were heavily engaged, which occasionally made a redistribution of patients necessary. MATERIAL AND METHODS: For managing COVID-19-related hospital capacities and patient allocation, crisis management squads in Bavaria were expanded by disaster task force medical officers ("Ärztlicher Leiter Führungsgruppe Katastrophenschutz" [MO]) with substantial executive authority. The authors report their experiences as MO concerning the superordinate patient allocation management in the district of Upper Palatinate (Oberpfalz) in eastern Bavaria. RESULTS: By abandoning routine patient care and building up additional ICU resources, surge capacity for the treatment of COVID-19 patients was generated in hospitals. In parts of the Oberpfalz, ICU capacities were almost entirely occupied by patients with corona virus infections, making reallocation to other hospitals within the district and beyond necessary. The MO managed patient pathways in an escalating manner by defining local (within the region of responsibility of a single MO), regional (within the district), and cross-regional (over district borders) reallocation lanes, as needed. When regional or cross-regional reallocation lanes had to be established, an additional management level located at the district government was involved. Within the determined reallocation lanes, emitting and receiving hospitals mutually agreed on any patient transfer without explicitly involving the MO, thereby maintaining the established interhospital routine transfer procedures. The number of patients and available treatment resources at each hospital were monitored with the help of a web-based treatment capacity registry. If indicated, reallocation lanes were dynamically revised according to the present situation. To oppose further virus spreading in nursing homes, the state government prohibited patient allocation to these facilities, which led to considerably longer hospital length of stay of convalescent elderly and/or dependent patients. In parallel to the flattening of the COVID-19 incidence curve, routine hospital patient care could be re-established in a stepwise manner. CONCLUSION: Patient allocation during the state of emergency by the MO sought to keep up routine interhospital reallocation procedures as much as possible, thereby reducing management time and effort. Occasionally, difficulties were observed during patient allocations crossing district borders, if other MO followed different management principles. The nursing home blockade and conflicting financial interests of hospitals posed challenges to the work of the disaster task force medical officers.

Heme oxygenase-1 protects endothelial cells from the toxicity of air pollutant chemicals.

Diesel exhaust particles (DEPs) are a major component of diesel emissions, responsible for a large portion of their toxicity. In this study, we examined the toxic effects of DEPs on endothelial cells and the role of DEP-induced heme oxygenase-1 (HO-1) expression. Human microvascular endothelial cells (HMECs) were treated with an organic extract of DEPs from an automobile engine (A-DEP) or a forklift engine (F-DEP) for 1 and 4h. ROS generation, cell viability, lactate dehydrogenase leakage, expression of HO-1, inflammatory genes, cell adhesion molecules and unfolded protein respone (UPR) gene were assessed. HO-1 expression and/or activity were inhibited by siRNA or tin protoporphyrin (Sn PPIX) and enhanced by an expression plasmid or cobalt protoporphyrin (CoPPIX). Exposure to 25µg/ml of A-DEP and F-DEP significantly induced ROS production, cellular toxicity and greater levels of inflammatory and cellular adhesion molecules but to a different degree. Inhibition of HO-1 enzymatic activity with SnPPIX and silencing of the HO-1 gene by siRNA enhanced DEP-induced ROS production, further decreased cell viability and increased expression of inflammatory and cell adhesion molecules. On the other hand, overexpression of the HO-1 gene by a pcDNA 3.1D/V5-HO-1 plasmid significantly mitigated ROS production, increased cell survival and decreased the expression of inflammatory genes. HO-1 expression protected HMECs from DEP-induced prooxidative and proinflammatory effects. Modulation of HO-1 expression could potentially serve as a therapeutic target in an attempt to inhibit the cardiovascular effects of ambient PM.

Predicting early complications in patients with spinal gunshot wounds: A multicenter study.

Introduction: There is a wide variation in the clinical presentation of spinal gunshot wounds ranging from isolated minor stable fractures to extremely severe injuries with catastrophic neurological damage. Research question: we aim to analyze the risk factors for early complications and impact of surgical treatment in patients with spinal gunshot wounds. Material and methods: This is a multicentre retrospective case-control study to compare patients with spinal gunshot wounds who had early complications with those who did not. The following matching criteria were used: sex (1:1), injury level (1:1) and age (±5 years). Univariate and multivariate analyses were performed using logistic regression. Results: Results: Among 387 patients, 36.9 % registered early complications, being persistent pain (n = 32; 15 %), sepsis/septic shock (n = 28; 13 %), pneumonia (n = 27; 13 %) and neurogenic bladder (n = 27; 12 %) the most frequently reported. After case-control matched analysis, we obtained 133 patients who suffered early complications (cases) and 133 patients who did not as control group, not differing significantly in sex (p = 1000), age (p = 0,535) and injury level (p = 1000), while the 35 % of complications group required surgical treatment versus 15 % of the non-complication group (p < 0.001). On multivariable analysis, significant predictors of complications were surgical treatment for spinal injury (OR = 3.50, 95 % CI = 1.68-7.30), dirty wound (3.32, 1.50-7.34), GCS ≤8 (3.56, 1.17-10.79), hemodynamic instability (2.29, 1.07-4.88), and multiple bullets (1.97, 1.05-3.67). Discussion and conclusion: Spinal gunshot wounds are associated with a high risk of early complications, especially when spinal surgery is required, and among patients with dirty wound, low level of consciousness, hemodynamic instability, and multiple bullets.

Management of decontamination in chemical accidents: a laboratory model.

Rapid and efficient decontamination of the skin is a major task for emergency rescue services in the event of a chemical accident involving humans. While rinsing the skin with water (and soap) has been the standard procedure, some skepticism has developed in recent years regarding the situational suitability of this method. The efficacy of three different decontamination materials/techniques (Easyderm® cleaning cloth, water-soaked all-purpose sponge, rinsing with water) in removing Capsaicin, Bromadiolone, Paraquat and 2,2'-dichlorodiethylether (DCEE) from porcine skin was compared. Different cleaning motions (wiping, twisting, pressing) with the Easyderm® were evaluated for their effectiveness in removing Capsaicin from porcine skin. Finally, the impact of different exposure times of the skin to Capsaicin on the decontamination process were investigated. Contaminant recovery rates (CRRs) were analysed in the skin and in each decontamination material using high-performance-liquid-chromatography (HPLC; used for Capsaicin, Bromadiolone, Paraquat) or gas chromatography (GC; used for DCEE). Wiping the skin with the amphiphilic Easyderm® was most effective for decontamination of Capsaicin and DCEE, while the water rinsing method gave the best results for removing Paraquat and Bromadiolone. Both wiping with the Easyderm® and rotating the Easyderm® were significantly more effective in cleaning Capsaicin-contaminated skin than pressing the Easyderm® on the contamination area alone. Prolonged exposure times of the porcine skin to Capsaicin were associated with a decrease in efficacy of the following decontamination. Emergency rescue services should have materials available that can remove both hydrophilic and hydrophobic substances from skin. Since not all of our results for comparing different decontamination materials were as distinct as we expected, there are likely several other factors determining the efficacy of skin decontamination in some cases. Time is key; therefore, first responders should try to begin the decontamination process as soon as possible after arriving at the scene.

[Management of COVID-19 mass casualty incidents in nursing and retirement homes]. / Managementstrategie für den Massenanfall von Erkrankten/Infizierten in Alten- und Pflegeheimen im Kontext der COVID-19-Pandemie.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, outbreaks in inpatient care facilities, which grow into a large-scale emergency scenario, are frequently observed. A standardized procedure analogous to algorithms for mass casualty incidents (MCI) is lacking. METHODS: Based on a case report and the literature, the authors present a management strategy for infectious MCI during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic and distinguish it from traumatic MCI deployment tactics. RESULTS: This management strategy can be divided into three phases, beginning with the acute emergency response including triage, stabilization of critical patients, and transport of patients requiring hospitalization. Phase 2 involves securing the facility's operational readiness, or housing residents elsewhere in case staff are infected or quarantined to a relevant degree. Phase 3 marks the return to regular operations. DISCUSSION: Phase 1 is based on usual MCI principles, phase 2 on hospital crisis management. Avoiding evacuation of residents to relieve hospitals is an important operational objective. The lack of mission and training experience with such situations, the limited applicability of established triage algorithms, and the need to coordinate a large number of participants pose challenges. CONCLUSION: This strategic model offers a practical, holistic approach to the management of infectious mass casualty scenarios in nursing facilities.

A novel monoclonal IgG1 antibody specific for Galactose-alpha-1,3-galactose questions alpha-Gal epitope expression by bacteria.

The alpha-Gal epitope (α-Gal) with the determining element galactose-α1,3-galactose can lead to clinically relevant allergic reactions and rejections in xenotransplantation. These immune reactions can develop because humans are devoid of this carbohydrate due to evolutionary loss of the enzyme α1,3-galactosyltransferase (GGTA1). In addition, up to 1% of human IgG antibodies are directed against α-Gal, but the stimulus for the induction of anti-α-Gal antibodies is still unclear. Commensal bacteria have been suggested as a causal factor for this induction as α-Gal binding tools such as lectins were found to stain cultivated bacteria isolated from the intestinal tract. Currently available tools for the detection of the definite α-Gal epitope, however, are cross-reactive, or have limited affinity and, hence, offer restricted possibilities for application. In this study, we describe a novel monoclonal IgG1 antibody (27H8) specific for the α-Gal epitope. The 27H8 antibody was generated by immunization of Ggta1 knockout mice and displays a high affinity towards synthetic and naturally occurring α-Gal in various applications. Using this novel tool, we found that intestinal bacteria reported to be α-Gal positive cannot be stained with 27H8 questioning whether commensal bacteria express the native α-Gal epitope at all.

Characterization of New Allergens from the Venom of the European Paper Wasp Polistes dominula.

Discriminating Polistes dominula and Vespula spp. venom allergy is of growing importance worldwide, as systemic reactions to either species' sting can lead to severe outcomes. Administering the correct allergen-specific immunotherapy is therefore a prerequisite to ensure the safety and health of venom-allergic patients. Component-resolved diagnostics of Hymenoptera venom allergy might be improved by adding additional allergens to the diagnostic allergen panel. Therefore, three potential new allergens from P. dominula venom-immune responsive protein 30 (IRP30), vascular endothelial growth factor C (VEGF C) and phospholipase A2 (PLA2)-were cloned, recombinantly produced and biochemically characterized. Sera sIgE titers of Hymenoptera venom-allergic patients were measured in vitro to assess the allergenicity and potential cross-reactivity of the venom proteins. IRP30 and VEGF C were classified as minor allergens, as sensitization rates lay around 20-40%. About 50% of P. dominula venom-allergic patients had measurable sIgE titers directed against PLA2 from P. dominula venom. Interestingly, PLA2 was unable to activate basophils of allergic patients, questioning its role in the context of clinically relevant sensitization. Although the obtained results hint to a questionable benefit of the characterized P. dominula venom proteins for improved diagnosis of venom-allergic patients, they can contribute to a deeper understanding of the molecular mechanisms of Hymenoptera venoms and to the identification of factors that determine the allergenic potential of proteins.

Detection of free radicals by isolated perfusion of the rat brain following hemorrhagic stroke: a novel approach to cerebrovascular biomarker research.

Blood-borne biomarkers are a mainstay of diagnosis and follow-up in many diseases. For stroke, however, no reliable biomarkers have thus far been identified. To remedy this situation, we investigated the usefulness of a modified in situ isolated brain perfusion (IBP) technique for screening potential biomarker candidates. As a proof of concept, the production of reactive oxygen species (ROS) was estimated in a rat model of experimental intracerebral hemorrhage (ICH). After stereotactic infusion of whole blood into the rat striatum, we initiated IBP without intracranial manipulation or discontinuation of cerebral blood flow. To detect ROS, we employed the salicylate trapping method, which involves the hydroxylation of salicylic acid during oxidative stress into dihydroxybenzoic acid (DHBA), and quantification of the latter in venous eluate by using high-performance liquid chromatography. Venous eluate was collected separately from both injured and healthy hemispheres (n=10). Control groups consisted of sham-injured (n=4) and healthy animals (n=3). In animals subjected to ICH (n=10), 50% more 2,5-DHBA was detected in venous eluate on the injured side than in eluate on the contralateral side. Hemorrhagic hemispheres produced more 2,5-DHBA than hemispheres in sham-injured and healthy animals (72 and 110% more 2,5-DHBA, respectively). Isolated brain perfusion combined with salicylate trapping produced data indicating an elevation in the formation of ROS subsequent to ICH. Our findings suggest that isolated in situ brain perfusion is a promising approach to detecting biomarkers of cerebrovascular pathologic conditions.

Policy and Pandemic: The Changing Practice of Nephrology During the Coronavirus Disease-2019 Outbreak.

The coronavirus (coronavirus disease-2019) pandemic has changed care delivery for patients with end-stage kidney disease. We explore the US healthcare system as it pertains to dialysis care, including existing policies, modifications implemented in response to the coronavirus disease-2019 crisis, and possible next steps for policy makers and nephrologists. This includes policies related to resource management, use of telemedicine, prioritization of dialysis access procedures, expansion of home dialysis modalities, administrative duties, and quality assessment. The government has already established policies that have instated some flexibilities to help providers focus their response to the crisis. However, future policy during and after the coronavirus disease-2019 pandemic can bolster our ability to optimize care for patients with end-stage kidney disease. Key themes in this perspective are the importance of policy flexibility, clear strategies for emergency preparedness, and robust health systems that maximize accessibility and patient autonomy.

Flow-cytometric measurement of respiratory burst in rat polymorphonuclear granulocytes: Comparison of four cell preparation procedures, and concentration-response evaluation of soluble stimulants.

Polymorphonuclear neutrophils (PMNs) contribute to organ injury in sepsis, stroke, and other diseases. Evaluation of the oxidative burst by flow cytometry (FCM) is frequently applied to examine PMN status in humans, but rarely in rats. We established a method to assess granulocyte activation in rats by means of FCM analysis of oxidative burst. Two methods for PMN isolation involving Histopaque separation were investigated, and additionally two whole blood techniques. In addition, the concentration-response relation of the stimulants fMLP, PMA, TNF-alpha, and LPS has been determined, both as sole stimulants and for priming. A novel technique with diluted rat whole blood proved to be most appropriate for PMN preparation. One micromolar PMA and fMLP, respectively, are effective concentrations for PMN stimulation in rat whole blood. Priming with 0.1 mug/ml TNF-alpha and 1 mug/ml LPS, respectively, resulted in optimal additional stimulation. This study defined the appropriate conditions for evaluating the reactive oxygen derivate production in rat PMNs by flow cytometry. The rapid, simple, and reliable cell preparation procedure of whole blood dilution that preserves cell integrity and requires only small sample quantities. This is the first systematic dose-response evaluation of soluble stimulants of neutrophil respiratory burst in rats.

New data on direct ion storage dosemeters.

The DIS-1 dosemeter from the Finnish company RADOS is an innovative kind of passive electronic dosemeter for photon and beta radiation. This study examines the 'long-term' linear response behaviour, the calibration and readout accuracy with large samples of 'used' DIS-1 dosemeters especially in the low-dose region, which is of special interest for radiation protection issues. Our measurements prove the adequacy of the DIS-1 dosemeter for long-term-personal dosimetry. The fast and precise readout seems to make the DIS-1 dosemeter an ideal choice for personal dosimetry in low-dose environments.

Primary mass casualty incident triage: evidence for the benefit of yearly brief re-training from a simulation study.

BACKGROUND: Triage is a mainstay of early mass casualty incident (MCI) management. Standardized triage protocols aim at providing valid and reproducible results and, thus, improve triage quality. To date, there is little data supporting the extent and content of training and re-training on using such triage protocols within the Emergency Medical Services (EMS). The study objective was to assess the decline in triage skills indicating a minimum time interval for re-training. In addition, the effect of a one-hour repeating lesson on triage quality was analyzed. METHODS: A dummy based trial on primary MCI triage with yearly follow-up after initial training using the ASAV algorithm (Amberg-Schwandorf Algorithm for Primary Triage) was undertaken. Triage was assessed concerning accuracy, sensitivity, specificity, over-triage, under-triage, time requirement, and a comprehensive performance measure. A subgroup analysis of professional paramedics was made. RESULTS: Nine hundred ninety triage procedures performed by 51 providers were analyzed. At 1 year after initial training, triage accuracy and overall performance dropped significantly. Professional paramedic's rate of correctly assigned triage categories deteriorated from 84 to 71%, and the overall performance score decreased from 95 to 90 points (maximum = 100). The observed decline in triage performance at 1 year after education made it necessary to conduct re-training. A brief didactic lecture of 45 min duration increased accuracy to 88% and the overall performance measure to 97. CONCLUSIONS: To improve disaster preparedness, triage skills should be refreshed yearly by a brief re-education of all EMS providers.

Quality of inter-hospital transportation in 431 transport survivor patients suffering from acute respiratory distress syndrome referred to specialist centers.

BACKGROUND: The acute respiratory distress syndrome (ARDS) is a life-threatening condition. In special situations, these critically ill patients must be transferred to specialized centers for escalating treatment. The aim of this study was to evaluate the quality of inter-hospital transport (IHT) of ARDS patients. METHODS: We evaluated medical and organizational aspects of structural and procedural quality relating to IHT of patients with ARDS in a prospective nationwide ARDS study. The qualification of emergency staff, the organizational aspects and the occurrence of critical events during transport were analyzed. RESULTS: Out of 1234 ARDS patients, 431 (34.9%) were transported, and 52 of these (12.1%) treated with extracorporeal membrane oxygenation. 63.1% of transferred patients were male, median age was 54 years, and 26.8% of patients were obese. All patients were mechanically ventilated during IHT. Pressure-controlled ventilation was the preferred mode (92.1%). Median duration to organize the IHT was 165 min. Median distance for IHT was 58 km, and median duration of IHT 60 min. Forty-two patient-related and 8 technology-related critical events (11.6%, 50 of 431 patients) were observed. When a critical event occurred, the PaO2/FiO2 ratio before transport was significant lower (68 vs. 80 mmHg, p = 0.017). 69.8% of physicians and 86.7% of paramedics confirmed all transfer qualifications according to requirements of the German faculty guidelines (DIVI). CONCLUSIONS: The transport of critically ill patients is associated with potential risks. In our study the rate of patient- and technology-related critical events was relatively low. A severe ARDS with a PaO2/FiO2 ratio < 70 mmHg seems to be a risk factor for the appearance of critical events during IHT. The majority of transport staff was well qualified. Time span for organization of IHT was relatively short. ECMO is an option to transport patients with a severe ARDS safely to specialized centers. Trial registration NCT02637011 (ClinicalTrials.gov, Registered 15 December 2015, retrospectively registered).

Fischer-344 rats are unsuitable for the MCAO filament model due to their cerebrovascular anatomy.

Middle cerebral artery occlusion (MCAO) in Fischer-344 rats results in a small variance of infarct size. However, complications are frequent especially in aged Fisher-344 rats undergoing endovascular suture occlusion of the middle cerebral artery. Analyzing our experiences with 165 Wistar, 13 Sprague-Dawley and 10 F-344 rats, we compared the incidence of impossible thread advancement and subarachnoid hemorrhage, respectively. Magnetic resonance angiography (MRA) was applied to study the course of the internal carotid artery (ICA) in Fischer and Wistar rats. Finally, we performed a structured review of the literature from 1991 to 2005 evaluating reports on Fischer rats subjected to intraluminal filament MCAO. Complications like fruitless filament advancement or subarachnoid hemorrhage were found to be significantly more frequent in Fischer rats than in other strains. MRA revealed significantly more pronounced kinking of the ICA in F-344 than in Wistar rats. In seven publications available on filament MCAO in F-344 rats, complication rates of 50-100% were reported, corroborating our data. Surgical difficulties accompanied by high complication rates due to their cerebrovascular anatomy make Fischer rats unsuitable for filament MCAO. If the use of Fischer rats for studies on focal cerebral ischemia is indicated, other ischemia models than intraluminal suture occlusion should be chosen.

Application of clinical scanners in rats: experimental carotid imaging using magnetic resonance imaging, spiral computed tomography, and color duplex ultrasound.

BACKGROUND AND PURPOSE: Noninvasive small animal imaging allows for reduction of the required numbers of animals in research by providing the possibility of long-term follow-up at various time points. Additionally, correlation to the investigated respective human disease is possible as equivalent equipment is employed. The authors therefore evaluate feasibility and potential of color duplex sonography, computed tomography angiography (CTA), and magnetic resonance angiography (MRA) by the use of clinical scanners for carotid artery imaging in rats. METHODS: Male Wistar rats (n = 17) were subjected to color duplex sonography, CTA, and MRA of the common carotid artery (CCA) and the carotid bifurcation. Clinical scanners were used for the experiments and optimal parameter settings evaluated accounting for the different size of the animals. The applied imaging methods were analyzed in regard to image quality and practicability in laboratory settings. RESULTS: The CCA could be clearly displayed by all imaging modalities in all rats. Duplex sonography provided distinct images and reproducible basic functional information. CTA and MRA provided distinct images of the CCA and the carotid bifurcation in both axial and reconstructed 3-dimensional images. The authors further describe different indications for these imaging methods regarding spatial resolution, acquisition times, possible scanning range, and application of contrast agent. CONCLUSIONS: Color duplex sonography, CTA, and MRA are all feasible methods for imaging of the carotid arteries in rats. Images of sufficient clarity and resolution could be obtained by the use of clinical scanners, yielding information about vessel size, direction of blood flow, and adjacent structures. Further studies need to be performed that address investigations of pathological conditions such as flow disturbances or vessel stenosis.

In Vitro Induction of Endothelial Apoptosis of the Post-Hypoxic Blood-Brain Barrier by Isoflurane but Not by Sevoflurane and Midazolam.

BACKGROUND: The effects of anesthetics on the injured brain continue to be the subject of controversial discussion. Since isoflurane has recently been shown to induce apoptosis of cerebral endothelial cells, this study compared different anesthetic compounds regarding their potential to induce cerebro-vascular apoptosis. METHODS: The in vitro model of the blood-brain barrier used in this study consisted of astrocyte-conditioned human umbilical vein endothelial cells (AC-HUVEC) has been used. After 24 h of deep hypoxia and reoxygenation or control treatment, AC-HUVEC were exposed to 0, 0.5, 1.0, or 2.0 times the minimum alveolar concentration of isoflurane or sevoflurane, or 0, 75, 150, or 300 nM of midazolam for 2 h. After 24 h, AC-HUVEC were harvested, and the degree of apoptosis was assessed by means of Western blots for the Bax and Bcl-2 ratio and, for controls and the highest concentration groups, terminal deoxynucleotidyl-mediated dUTP-biotin nick end labeling (TUNEL). RESULTS: Without hypoxic pretreatment, 2.0 MAC of isoflurane slightly increased TUNEL intensity compared to control and sevoflurane, but without any significant changes in the Bax and Bcl-2 ratio. After hypoxic pretreatment, exposure to isoflurane led to a multifold increase in the Bax and Bcl-2 ratio in a dose dependent manner, which was also significantly higher than the ratio observed in the 2 MAC sevoflurane group. TUNEL intensity in the post-hypoxic 2 MAC isoflurane group was increased by a factor of 11 vs. control and by 40 vs. sevoflurane. Sevoflurane and midazolam did not significantly alter these markers of apoptosis, when compared to the control group. CONCLUSIONS: Isoflurane administered after hypoxia elevates markers of apoptosis in endothelial cells transdifferentiated to the cerebro-vascular endothelium. Endothelial apoptosis may be a previously underestimated mechanism of anesthetic neurotoxicity. Administration of high concentrations of isoflurane in experimental settings may have negative effects on the blood-brain barrier.

External carotid artery territory ischemia impairs outcome in the endovascular filament model of middle cerebral artery occlusion in rats.

BACKGROUND AND PURPOSE: Middle cerebral artery occlusion (MCAO) by an intraluminal filament is a widely accepted animal model of focal cerebral ischemia. In this procedure, cutting of the external carotid artery (ECA) is a prerequisite for thread insertion. However, the implications of ECA transsection have not yet been described. METHODS: After 90 minutes of filament MCAO or sham surgery, rats were evaluated for up to 14 days in terms of body weight development, core temperature, and motor performance. Repeated in vivo MRI of the head and neck was performed for quantification of brain edema and infarct volume. The temporal muscles were histologically analyzed postmortem. RESULTS: In 47% of all rats, ischemic tissue damage to the ipsilateral ECA area, including temporal, lingual, and pharyngeal musculature, was detectable by MRI. Histology of temporal muscles confirmed acute ischemic myopathy. Animals with ECA territory ischemia (ECA-I) showed delayed body weight development and poorer recovery of motor function. There was no difference in the extent of brain edema or final cerebral lesion size between ECA-I-affected and unaffected rats. CONCLUSIONS: Filament MCAO was complicated by the consequences of ECA ischemia in approximately half of all rats. Impaired mastication and swallowing functions restricted ingestion and resulted in postsurgical body weight loss and worse motor performance. Impaired cerebral microperfusion resulting from dehydration and reduced spontaneous motor activity resulting from reduced food and water uptake might have contributed to poorer neurological recovery in ECA ischemic rats. Thus, adverse effects caused by extracerebral ischemia with potential impact on outcome have to be considered in this stroke model.

Ketamine/xylazine anesthesia for radiologic imaging of neurologically impaired rats: dose response, respiratory depression, and management of complications.

In vivo imaging of rats represents an important tool for outcome evaluation in research on stroke, brain trauma, and other neurologic diseases. Since sedation of animals is necessary to avoid artifacts, a mixture of ketamine and xylazine is frequently used for anesthesia. We assessed the suitable dosage of narcotics and its correlation to severe respiratory adverse events in 269 cases of ketamine/xylazine anesthesia in male Wistar rats for performance of magnetic resonance imaging after middle cerebral artery occlusion (MCAO) or sham surgery. Anesthesia depth was not measured. Anesthesia was efficacious in avoiding movement artifacts during imaging. Necessary dosage was lower if rodents were subjected to MCAO instead of sham surgery, if body weight was below baseline, and if time since surgery was short. If anesthesia was induced during the first 2 days after surgery in animals with body weight loss, necessary dose rates were 27% below doses required for rats more than 10 days post-surgery with body weight above baseline (91.4/8.3 versus 125.1/11.3 mg of ketamine/xylazine/kg). A dose adaptation scale for the prediction of necessary dose rates was developed. Apnea developed in 3.3% of all animals. Use of ketamine/xylazine anesthesia for imaging procedures is feasible and safe, though it is associated with a small risk of respiratory arrest. In case of apnea, inspiration can be provoked by a puff of air into the rat's pelt. If unsuccessful, endotracheal intubation and mechanical ventilation are needed until spontaneous breathing is restored or xylazine effects are antagonized.