Airway management in neonates and infants: European Society of Anaesthesiology and Intensive Care and British Journal of Anaesthesia joint guidelines.

Airway management is required during general anaesthesia and is essential for life-threatening conditions such as cardiopulmonary resuscitation. Evidence from recent trials indicates a high incidence of critical events during airway management, especially in neonates or infants. It is important to define the optimal techniques and strategies for airway management in these groups. In this joint European Society of Anaesthesiology and Intensive Care (ESAIC) and British Journal of Anaesthesia (BJA) guideline on airway management in neonates and infants, we present aggregated and evidence-based recommendations to assist clinicians in providing safe and effective medical care. We identified seven main areas of interest for airway management: i) preoperative assessment and preparation; ii) medications; iii) techniques and algorithms; iv) identification and treatment of difficult airways; v) confirmation of tracheal intubation; vi) tracheal extubation, and vii) human factors. Based on these areas, Population, Intervention, Comparison, Outcomes (PICO) questions were derived that guided a structured literature search. GRADE (Grading of Recommendations, Assessment, Development and Evaluation) methodology was used to formulate the recommendations based on those studies included with consideration of their methodological quality (strong '1' or weak '2' recommendation with high 'A', medium 'B' or low 'C' quality of evidence). In summary, we recommend: 1. Use medical history and physical examination to predict difficult airway management (1C). 2. Ensure adequate level of sedation or general anaesthesia during airway management (1B). 3. Administer neuromuscular blocker before tracheal intubation when spontaneous breathing is not necessary (1C). 4. Use a videolaryngoscope with an age-adapted standard blade as first choice for tracheal intubation (1B). 5. Apply apnoeic oxygenation during tracheal intubation in neonates (1B). 6. Consider a supraglottic airway for rescue oxygenation and ventilation when tracheal intubation fails (1B). 7. Limit the number of tracheal intubation attempts (1C). 8. Use a stylet to reinforce and preshape tracheal tubes when hyperangulated videolaryngoscope blades are used and when the larynx is anatomically anterior (1C). 9. Verify intubation is successful with clinical assessment and end-tidal CO2 waveform (1C). 10. Apply high-flow nasal oxygenation, continuous positive airway pressure or nasal intermittent positive pressure ventilation for postextubation respiratory support, when appropriate (1B).

Airway management in neonates and infants: European Society of Anaesthesiology and Intensive Care and British Journal of Anaesthesia joint guidelines.

Airway management is required during general anaesthesia and is essential for life-threatening conditions such as cardiopulmonary resuscitation. Evidence from recent trials indicates a high incidence of critical events during airway management, especially in neonates or infants. It is important to define the optimal techniques and strategies for airway management in these groups. In this joint European Society of Anaesthesiology and Intensive Care (ESAIC) and British Journal of Anaesthesia (BJA) guideline on airway management in neonates and infants, we present aggregated and evidence-based recommendations to assist clinicians in providing safe and effective medical care. We identified seven main areas of interest for airway management: i) preoperative assessment and preparation; ii) medications; iii) techniques and algorithms; iv) identification and treatment of difficult airways; v) confirmation of tracheal intubation; vi) tracheal extubation, and vii) human factors. Based on these areas, Population, Intervention, Comparison, Outcomes (PICO) questions were derived that guided a structured literature search. GRADE (Grading of Recommendations, Assessment, Development and Evaluation) methodology was used to formulate the recommendations based on those studies included with consideration of their methodological quality (strong '1' or weak '2' recommendation with high 'A', medium 'B' or low 'C' quality of evidence). In summary, we recommend: 1. Use medical history and physical examination to predict difficult airway management (1С). 2. Ensure adequate level of sedation or general anaesthesia during airway management (1B). 3. Administer neuromuscular blocker before tracheal intubation when spontaneous breathing is not necessary (1С). 4. Use a videolaryngoscope with an age-adapted standard blade as first choice for tracheal intubation (1B). 5. Apply apnoeic oxygenation during tracheal intubation in neonates (1B). 6. Consider a supraglottic airway for rescue oxygenation and ventilation when tracheal intubation fails (1B). 7. Limit the number of tracheal intubation attempts (1C). 8. Use a stylet to reinforce and preshape tracheal tubes when hyperangulated videolaryngoscope blades are used and when the larynx is anatomically anterior (1C). 9. Verify intubation is successful with clinical assessment and end-tidal CO 2 waveform (1C). 10. Apply high-flow nasal oxygenation, continuous positive airway pressure or nasal intermittent positive pressure ventilation for postextubation respiratory support, when appropriate (1B).

Perioperative anaesthetic management and short-term outcome of neonatal repair of oesophageal atresia with or without tracheo-oesophageal fistula in Europe: A sub-analysis of the neonate and children audit of anaesthesia practice in Europe (NECTARINE) prospective multicenter observational study.

BACKGROUND: Oesophageal atresia with or without a tracheo-oesophageal fistula is a congenital abnormality that usually requires surgical repair within the first days of life. OBJECTIVE: Description of the perioperative anaesthetic management and outcomes of neonates undergoing surgery for oesophageal atresia with or without a tracheo-oesophageal fistula, included in the 'neonate and children audit of anaesthesia practice in Europe' (NECTARINE) database. DESIGN: Sub-analyses of prospective observational NECTARINE study. SETTING: European multicentre study. PATIENTS: Neonates who underwent surgery for oesophageal atresia with or without a tracheo-oesophageal fistula in the NECTARINE cohort were selected. MAIN OUTCOME MEASURES: Incidence rates with 95% confidence intervals were calculated for peri-operative clinical events which required a predetermined intervention, postoperative complications, and mortality. RESULTS: One hundred and three neonates undergoing a first surgical intervention for oesophageal atresia with or without a tracheo-oesophageal fistula repair were identified. Their median gestational age was 38 weeks with a median birth weight of 2840 [interquartile range 2150 to 3150] grams. Invasive monitoring was used in 66% of the procedures. The incidence of perioperative clinical events was 69% (95% confidence interval 59 to 77%), of 30-day postoperative complications 47% (95% confidence interval 38 to 57%) and the 30- and 90 days mortality rates were 2.1% and 2.6%, respectively. CONCLUSION: Oesophageal atresia with or without a tracheo-oesophageal fistula repair in neonates is associated with a high number of perioperative interventions in response to clinical events, a high incidence of postoperative complications, and a substantial mortality rate.

Optical 4D oxygen mapping of microperfused tissue models with tunable in vivo-like 3D oxygen microenvironments.

Sufficient and controllable oxygen supply is essential for in vitro 3D cell and tissue culture at high cell densities, which calls for volumetric in situ oxygen analysis methods to quantitatively assess the oxygen distribution. This paper presents a general approach for accurate and precise non-contact 3D mapping of oxygen tension in high cell-density cultures via embedded commercially available oxygen microsensor beads read out by confocal phosphorescence lifetime microscopy (PLIM). Optimal acquisition conditions and data analysis procedures are established and implemented in a publicly available software package. The versatility of the established method is first demonstrated in model-assisted fluidic design of microperfused 3D printed hydrogel culture chips with the aim of full culture oxygenation, and subsequently for monitoring and maintenance of physiologically relevant spatial and temporal oxygen gradients in the 3D printed chips controlled by static or dynamic flow conditions during 3D culture.

In vitro investigation of endocrine disrupting effects of pesticides on Ca2+-signaling in human sperm cells through actions on the sperm-specific and steroid-activated CatSper Ca2+-channel.

BACKGROUND: Ca2+-signaling controls sperm cell functions necessary for successful fertilization. Multiple endocrine disrupting chemicals have been found to interfere with normal Ca2+-signaling in human sperm cells through an activation of the sperm-specific CatSper Ca2+-channel, which is vital for normal male fertility. OBJECTIVES: We investigated 53 pesticides for their ability to interfere with CatSper mediated Ca2+-signaling and function in human sperm cells. METHODS: Effects of the pesticides on Ca2+-signaling in human sperm cells were evaluated using a Ca2+-fluorometric assay. Effects via CatSper were assessed using the specific CatSper inhibitor RU1968. Effects on human sperm function and viability were assessed using an image cytometry-based acrosome reaction assay and the modified Kremer's sperm-mucus penetration assay. RESULTS: 28 of 53 pesticides were found to induce Ca2+-signals in human sperm cells at 10 µM. The majority of these 28 active pesticides induced Ca2+-signals through CatSper and interfered with subsequent Ca2+-signals induced by the two endogenous CatSper ligands progesterone and prostaglandin E1. Multiple active pesticides were found to affect Ca2+-mediated sperm functions and viability at 10 µM. Low nM dose mixtures of the active pesticides alone or in combination with other environmental chemicals were found to significantly induce Ca2+-signals and inhibit Ca2+-signals induced subsequently by progesterone and prostaglandin E1. CONCLUSIONS: Our results show that pesticides, both alone and in low nM dose mixtures, interfere with normal Ca2+-signaling in human sperm cells in vitro in low nM concentrations. Biomonitoring of the active pesticides in relevant matrices such as blood and reproductive fluids is very limited and the effects of real time human pesticide exposure on human sperm cells and fertility thus remains largely unknown. To which extent human pesticide exposure affects the chances of a successful fertilization in humans in vivo needs further research.

Congenital anomalies of the large intrathoracic airways.

Congenital lung lesions are numerous but rare in individual clinical practice. They do require close multidisciplinary collaboration between health care professionals. This educational review will focus on the pathophysiology, clinical manifestations, surgical approaches, and anesthetic management of congenital anomalies of the large intrathoracic airways: congenital tracheal stenosis, tracheal agenesis, tracheal diverticulum, bronchial anomalies (tracheal, esophageal, or bridging bronchus), congenital lung malformations, lung sequestrations and Scimitar syndrome, lobar emphysema, Williams-Campbell syndrome, and pleuropulmonary blastoma. In addition, this review will illustrate common pitfalls and challenges related to the anesthesia management with emphasis on ventilation and correct endotracheal tube positioning.

Report of two cases of endobronchial tumour mass resection in children.

PURPOSE: Anesthesia for endotracheal tumour mass resection in pediatric patients is a rare, complex, and high-risk procedure. The purpose of this case report is to emphasize the importance of multidisciplinary team collaboration and close communication during the perioperative management of shared airway surgery. CLINICAL FEATURES: A six-year-old boy with no previous history of comorbidity and a 13-yr-old boy with a six-month history of upper respiratory tract infection, refractory asthma, chronic wheeze, and exercise-related dyspnea presented for acute endobronchial tumour mass resection. Decreased pulmonary function, religious beliefs (Jehovah's Witness), risk of intraluminal bleeding, and imminent complete airway collapse constitute areas of specific interest. CONCLUSION: Anesthesia for endotracheal tumour mass resection in pediatric patients is a rare, complex, and high-risk procedure. Decreased pulmonary function and low respiratory reserves combined with the need for extensive surgical airway access warrants multidisciplinary team collaboration and close communication. Maintaining spontaneous respiration is paramount to reduce the risk of hypoxemia-induced adverse events and preoperative considerations should include the possible need for extracorporeal membrane oxygenation. Finally, the use of nasal high flow for shared airway surgery shows promising prospects warranting further investigation.

RéSUMé: OBJECTIF: L'anesthésie pour la résection de masse tumorale endotrachéale chez les patients pédiatriques est une intervention à la fois rare, complexe, et à haut risque. L'objectif de cette présentation de cas est de souligner l'importance de la collaboration multidisciplinaire et d'une bonne communication entre les équipes pendant la prise en charge périopératoire d'une chirurgie sur des voies aériennes partagées. ÉLéMENTS CLINIQUES: Un garçon de six ans sans antécédents et un garçon de 13 ans avec des antécédents de six mois d'infection des voies respiratoires supérieures, d'asthme réfractaire, de respiration sifflante (wheeze) chronique, et de dyspnée liée à l'exercice, se sont présentés pour une résection semi-urgente d'une masse tumorale endobronchique. Une réduction de la fonction pulmonaire, les croyances religieuses (témoins de Jéhovah), le risque de saignement intraluminal, et l'imminence d'un collapsus complet des voies aériennes étaient les domaines d'intérêt spécifique. CONCLUSION: L'anesthésie pour la résection de masse tumorale endotrachéale chez les patients pédiatriques est une intervention à la fois rare, complexe, et à haut risque. Une fonction pulmonaire réduite et des réserves respiratoires diminuées, combinées au besoin d'un accès chirurgical étendu aux voies aériennes, nécessitent une collaboration multidisciplinaire et une excellente communication entre les équipes. Il est essentiel de maintenir la respiration spontanée pour réduire le risque d'événements indésirables induits par l'hypoxémie, et les considérations préopératoires devraient inclure le besoin possible d'oxygénation extracorporelle (ECMO). En conclusion, l'utilisation d'une lunette à haut débit nasal pour la chirurgie sur des voies aériennes partagées est prometteuse, justifiant des études plus approfondies.

Best practice & research clinical anesthesiology: Safety and quality in perioperative anesthesia care. Update on safety in pediatric anesthesia.

Pediatric anesthesia is large part of anesthesia clinical practice. Children, parents and anesthesiologists fear anesthesia because of the risk of acute morbidity and mortality. Modern anesthesia in otherwise healthy children above 1 year of age in developed countries has become very safe due to recent advance in pharmacology, intensive education, and training as well as centralization of care. In contrast, anesthesia in these children in low-income countries is associated with a high risk of mortality due to lack of basic resources and adequate training of health care providers. Anesthesia for neonates and toddlers is associated with significant morbidity and mortality. Anesthesia-related (near) critical incidents occur in 5% of anesthetic procedures and are largely dependent on the skills and up-to-date knowledge of the whole perioperative team in the specific needs for children. An investment in continuous medical education of the perioperative staff is required and international standard operating protocols for common procedures and critical situations should be defined.

Long-term IV access in paediatrics - why, what, where, who and how.

Establishment of long-term central venous access imposes the risk of procedural adverse events (air embolism, pneumothorax, accidental arterial cannulation of the great vessels, tricuspid valve damage and cardiac tamponade) as well as the risk of increased morbidity and mortality due to catheter related blood stream infections, vessel stenosis, deep vein thrombosis and the often high risk anaesthetic management of syndromic children. This narrative review aims to provide a historical and clinical background for the development and use of CVADs (central venous access devices), origin and management of the most common complications (catheter related thrombosis, infections and persistent withdrawal occlusion) and present the reader with an update on the "why, what, where, who and how" in paediatric long-term central venous access. Finally, we will present the reader with a clinical method for applying a retrograde inserted tunnelled and cuffed catheter using the left brachiocephalic vein access.

Using assessment criteria for pesticides to evaluate the endocrine disrupting potential of non-pesticide chemicals: Case butylparaben.

Regulation of chemicals with endocrine disrupting properties depend on the use of the chemical rather than its intrinsic properties. Within the EU, the only criteria currently in place for identifying an endocrine disrupting chemical (EDC) are those developed for biocidal and plant protection products. We argue that ECHA/EFSA guidance for assessing endocrine disrupting properties of biocidal and plant protection products can be applied to all chemicals independent of their intended use. We have assessed the REACH-registered compound butylparaben (CAS 94-36-8), a preservative used primarily in cosmetics. Based on scientific evidence of adverse reproductive effects and endocrine activity, the open literature suggest that butylparaben is an EDC. By applying the ECHA/EFSA guidance for pesticides and biocides, we identify butylparaben as a compound with endocrine disrupting properties. Even though available data is markedly different from that for biocides and pesticides, it was possible to reach this conclusion. More generally, we propose that the ECHA/EFSA guidance can and should be used for identification of EDC regardless of their intended application.

Native Whey Induces Similar Adaptation to Strength Training as Milk, despite Higher Levels of Leucine, in Elderly Individuals.

BACKGROUND: Large amounts of protein (40 g) or supplementing suboptimal servings of protein with leucine are able to overcome the anabolic resistance in elderly muscle. Our aim was to compare the effects of supplementation of native whey, high in leucine, with milk on gains in muscle mass and strength during a period of strength training, in elderly individuals. METHODS: In this double-blinded, randomized, controlled study, a total of 30 healthy men and women received two daily servings of 20 g of either milk protein or native whey, during an 11-week strength training intervention. Muscle strength, lean mass, m. vastus lateralis thickness, muscle fiber area, and resting and post-exercise phosphorylation of p70S6K, 4E-BP1, and eEF-2 were assessed prior to and after the intervention period. RESULTS: Muscle mass and strength increased, by all measures applied in both groups (p < 0.001), with no differences between groups (p > 0.25). p70S6K phosphorylation increased (~1000%, p < 0.045) 2 h after exercise in the untrained and trained state, with no differences between supplements. Total and phosphorylated mTORC-1 decreased after training. CONCLUSION: Supplementation with milk or native whey during an 11-week strength training period increased muscle mass and strength similarly in healthy elderly individuals.

Prothrombin complex concentrate for reversal of vitamin K antagonist treatment in bleeding and non-bleeding patients.

BACKGROUND: Treatment with vitamin K antagonists is associated with increased morbidity and mortality. Reversal therapy with prothrombin complex concentrate (PCC) is used increasingly and is recommended in the treatment of patients with bleeding complications undertaking surgical interventions, as well as patients at high risk of bleeding. Evidence is lacking regarding indication, dosing, efficacy and safety. OBJECTIVES: We assessed the benefits and harms of PCC compared with fresh frozen plasma in the acute medical and surgical setting involving vitamin K antagonist-treated bleeding and non-bleeding patients. We investigated various outcomes and predefined subgroups and performed sensitivity analysis. We examined risks of bias and applied trial sequential analyses (TSA) to examine the level of evidence, and we prepared a 'Risk of bias' table to test the quality of the evidence. SEARCH METHODS: We searched the following databases from inception to 1 May 2013: Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE (Ovid SP); EMBASE (Ovid SP); International Web of Science; Latin American and Caribbean Health Sciences Literature (LILACS) (via BIREME); the Chinese Biomedical Literature Database; advanced Google and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We applied a systematic and sensitive search strategy to identify relevant randomized clinical trials and imposed no language or date restrictions. We adapted our MEDLINE search strategy for searches in all other databases. We reran the search in October 2014 and found one potential new study of interest. We added this study to a list of 'Studies awaiting classification', and we will incorporate this study into the formal review findings at the time of the review update. SELECTION CRITERIA: We included randomized controlled trials (RCTs), irrespective of publication status, date of publication, blinding status, outcomes published or language. We contacted investigators and study authors to request relevant data. DATA COLLECTION AND ANALYSIS: Three review authors independently abstracted data and resolved disagreements by discussion. Our primary outcome measures were 'overall mortality longest follow-up' and 'overall 28-day mortality'. We performed subgroup analyses to assess the effects of PCC in adults in terms of various clinical and physiological outcomes. We presented pooled estimates of the effects of interventions on dichotomous outcomes as risk ratios (RRs), and on continuous outcomes as mean differences (MDs), with 95% confidence intervals (CIs). We assessed risk of bias by assessing trial methodological components and risk of random error through TSA. MAIN RESULTS: We included four RCTs with a total of 453 participants and determined that none of these trials had overall low risk of bias. We found six ongoing trials from which we were unable to retrieve further data. Three trials provided data on mortality. Meta-analysis showed no statistical effect on overall mortality (RR 0.93, 95% CI 0.37 to 2.33; very low quality of evidence). We were unable to associate use of PCC with the number of complications probably related to the intervention (RR 0.92, 95% CI 0.78 to 1.09; very low quality of evidence). Lack of transfusion data and apparent differences in study design prevented review authors from finding a beneficial effect of PCC in reducing the volume of fresh frozen plasma (FFP) transfused to reverse the effect of vitamin K antagonist treatment. The number of new occurrences of transfusion of red blood cells (RBCs) did not seem to be associated with the use of PCC (RR 1.08, 95% CI 0.82 to 1.43; very low quality of evidence). Still, the included studies demonstrate the possibility of equally reversing vitamin K-induced coagulopathy using PCC without the need for transfusion of FFP. No effect on other predefined outcomes was observed. AUTHORS' CONCLUSIONS: In the four included RCTs, use of prothrombin complex concentrate does not appear to reduce mortality or transfusion requirements but demonstrates the possibility of reversing vitamin K-induced coagulopathy without the need for transfusion of fresh frozen plasma. All included trials have high risk of bias and are underpowered to detect mortality, benefit or harm. Clinical and statistical heterogeneity is high, and definitions of clinically important outcomes such as adverse events are highly dissimilar between trials. Only weak observational evidence currently supports the use of PCC in vitamin K antagonist-treated bleeding and non-bleeding patients, and the current systematic review of RCTs does not support the routine use of PCC over FFP. Additional high-quality research is urgently needed.

Fibrinogen concentrate in bleeding patients.

BACKGROUND: Hypofibrinogenaemia is associated with increased morbidity and mortality, but the optimal treatment level, the use of preemptive treatment and the preferred source of fibrinogen remain disputed. Fibrinogen concentrate is increasingly used and recommended for bleeding with acquired haemostatic deficiencies in several countries, but evidence is lacking regarding indications, dosing, efficacy and safety. OBJECTIVES: We assessed the benefits and harms of fibrinogen concentrate compared with placebo or usual treatment for bleeding patients. SEARCH METHODS: We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 8); MEDLINE (1950 to 9 August 2013); EMBASE (1980 to 9 August 2013); International Web of Science (1964 to 9 August 2013); CINAHL (1980 to 9 August 2013); LILACS (1982 to 9 August 2013); and the Chinese Biomedical Literature Database (up to 10 November 2011), together with databases of ongoing trials. We contacted trial authors, authors of previous reviews and manufacturers in the field. SELECTION CRITERIA: We included all randomized controlled trials (RCTs), irrespective of blinding or language, that compared fibrinogen concentrate with placebo/other treatment or no treatment in bleeding patients, excluding neonates and patients with hereditary bleeding disorders. DATA COLLECTION AND ANALYSIS: Three review authors independently abstracted data; we resolved any disagreements by discussion. Our primary outcome measure was all-cause mortality. We performed subgroup and sensitivity analyses to assess the effects of fibrinogen concentrate in adults and children in terms of various clinical and physiological outcomes. We presented pooled estimates of the effects of intervention on dichotomous outcomes as risk ratios (RRs) and on continuous outcomes as mean differences, with 95% confidence intervals (CIs). We assessed the risk of bias through assessment of trial methodological components and the risk of random error through trial sequential analysis. MAIN RESULTS: We included six RCTs with a total of 248 participants; none of the trials were determined to have overall low risk of bias. We found 12 ongoing trials, from which we were unable to retrieve any data. Only two trials provided data on mortality, and one was a zero event study; thus the meta-analysis showed no statistically significant effect on overall mortality (2.6% vs 9.5%, RR 0.28, 95% CI 0.03 to 2.33). Our analyses on blood transfusion data suggest a beneficial effect of fibrinogen concentrate in reducing the incidence of allogenic transfusions (RR 0.47, 95% CI 0.31 to 0.72) but show no effect on other predefined outcomes, including adverse events such as thrombotic episodes. AUTHORS' CONCLUSIONS: In the six available RCTs of elective surgery, fibrinogen concentrate appears to reduce transfusion requirements, but the included trials are of low quality with high risk of bias and are underpowered to detect mortality, benefit or harm. Furthermore, data on mortality are lacking, heterogeneity is high and acute or severe bleeding in a non-elective surgical setting remains unexplored. Currently, weak evidence supports the use of fibrinogen concentrate in bleeding patients, as tested here in primarily elective cardiac surgery. More research is urgently needed.

[Discontinuation of treatment with platelet aggregation inhibitors in surgical patients with cardiac stents]. / Pause med trombocytaggregationshaemmere hos kirurgiske patienter med kardiel stent.

Dual antiplatelet therapy with aspirin and clopidogrel is increasingly used for secondary prevention of cardiovascular events in patients with percutaneous coronary intervention. Anesthesiologists and surgeons are faced with the challenge of managing these patients prior to a surgical procedure. Premature discontinuation of antiplatelet therapy constitutes a substantial risk of stent thrombosis, myocardial infarction and death. Continuing therapy increases the risk of bleeding. We provide the latest evidence on this topic for patients awaiting non-cardiac surgery.

[Optical and video-assisted laryngoscopy for problematic airways]. / Optisk og videoassisteret laryngoskopi ved vanskelige luftveje.

Airway management is one of the greatest anaesthesiologic challenges. Direct laryngoscopy using a standard McIntosh laryngoscope has been the predominant intubation choice for many years. Videolaryngoscopy is becoming a widely accepted airway management technique owing to its potential advantages over direct laryngoscopy including a better view of the larynx, reduced tracheal intubation time and educational value. We present an overview of the currently most used optical and video-assisted laryngoscopes with a special focus on the McGrath Series 5 videolaryngoscope.

Neural tissue-spheres: a microexplant culture method for propagation of precursor cells from the rat forebrain subventricular zone.

By combining new and established protocols we have developed a procedure for isolation and propagation of neural precursor cells from the forebrain subventricular zone (SVZ) of newborn rats. Small tissue blocks of the SVZ were dissected and propagated en bloc as free-floating neural tissue-spheres (NTS) in EGF and FGF2 containing medium. The spheres were cut into quarters when passaged every 10-15th day, avoiding mechanical or enzymatic dissociation in order to minimize cellular trauma and preserve intercellular contacts. For analysis of regional differences within the forebrain SVZ, NTS were derived from three rostro-caudal levels of the lateral ventricles (anterior, intermediate and posterior) and propagated separately. Explants from all three levels produced proliferating NTS, but "anterior" NTS in general grew to smaller sizes than "intermediate" and "posterior" NTS. Posterior NTS moreover maintained their neurogenic potential throughout 77 days of propagation, while the ability of anterior NTS to generate neurons severely declined from day 40. The present procedure describes isolation and long-term expansion of forebrain SVZ tissue with potential preservation of the endogenous cellular content, thus allowing experimental studies of neural precursor cells and their niche.