Untersuchungen zur Lebensdauer von NEA-Photokathoden bei der Extraktion sehr hoher mittlerer Ströme

Die Produktion eines spinpolarisierten Strahls mit hohem mittleren Strom ist sowohl für den Betrieb von existierenden polarisierten Quellen als auch in noch stärkerem Maße für geplante zukünftige Projekte wichtig. Die Betriebszeit solcher Quellen wird durch die Abnahme der Quantenausbeute der Photokathode mit der Zeit begrenzt. Die Problematik der Abnahme der Quantenausbeute konnte durch die Reaktion der Kathodenoberfläche mit sauerstoffhaltigen Molekülen sowie durch Ionenbombardement geklärt werden. Im Laufe dieser Arbeit wurden, teilweise zum ersten Mal, Mechanismen untersucht, die zur Entstehung der chemisch aktiven Moleküle und der Ionen beitragen und weitere Effekte, die die Betriebszeit der polarisierten Quellen reduzieren. Die Experimente wurden an einer genauen Kopie der an MAMI vorhandenen polarisierten Quelle durchgeführt. Es wurde demonstriert, dass Erwärmung der Photokathode, Ioneneinfang und Strahlverlust aufgrund der Raumladungskräfte die Kathodenlebensdauer begrenzen können. Der erste Effekt ist Erwärmung der Photokathode. Die Laserleistung wird fast vollständig in Wärmeleistung umgesetzt, was zur Absenkung der Verfügbarkeit der polarisierten Quellen führen kann, und zwar unabhängig davon, ob der Photostrom produziert wird oder nicht. Der zweite Effekt ist Ionenbombardement mit den sowohl in der Beschleunigungsstrecke als auch in der Strahlführung entstehenden Ionen. Es wurde demonstriert, dass der in der Strahlführung entstehende Ionenstrom sogar größer ist als der in der Kanone. Unter bestimmten Bedingungen können die gebildeten Ionen durch das Potenzial des Elektronenstrahls eingefangen werden und die Kanone erreichen und damit zusätzlich zur Zerstörung der negativen Elektronenaffinität beitragen. Der dritte Effekt ist Strahlverlust. Es wurde demonstriert, dass die relativen Strahlverluste kleiner als 1*10-6 sein sollten, um eine Lebensdauer von mehr als 1000 Stunden beim Strom von 100 A zu erreichen, was für die vorhandene Apparatur möglich ist. Zur Erzeugung extrem hoher Ströme wurde zum ersten Mal im Bereich der spinpolarisierten Quellen das Prinzip der „Energierückgewinnung“ eingesetzt. Experimente bei einer mittleren Stromstärke von 11.4 mA und einer Spitzenstromstärke von 57 mA bei 1% Tastverhältnis wurden bereits durchgeführt.

Risultati funzionali a lungo termine dopo sutura o plicatura del diaframma

Obbiettivo. Analizzare la funzionalità polmonare e diaframmatica dopo interventi di plicatura del diaframma con rete di rinforzo peri-costale eseguiti per relaxatio e riparazione di ernia transdiaframmatica cronica mediante riduzione e sutura diretta. Metodi. Dal 1996 al 2010, 10 pazienti con relaxatio unilaterale del diaframma e 6 pazienti con ernia transdiaframmatica cronica misconosciuta sono stati sottoposti a chirurgia elettiva. Gli accertamenti preoperatori e al follow-up di 12 mesi includevano prove di funzionalità respiratoria, misura della pressione massimale inspiratoria alla bocca in clino e ortostatismo, emogasanlisi, TC del torace e dispnea score. Risultati. I pazienti dei due gruppi non differivano in termini di funzionalità respiratoria preoperatoria nè di complicanze postoperatorie; al follow-up a 12 mesi il gruppo Eventrazione mostrava un significativo aumento del FEV1% (+18,2 – p<0.001), FVC% (+12,8 – p<0.001), DLCO% (+6,84 – p=0,04) e pO2 (+9,8 mmHg – p<0.001). Al contrario nrl gruppo Ernia solo il miglioramento della pO2 era significativo (+8.3 – p=0.04). Sebbene la massima pressione inspiratoria (PImax) fosse aumentata in entrambi i gruppi al follow-up, i pazienti operati per ernia mostravano un miglioramento limitato con persistente caduta significativa della PImax dall’ortostatismo al clinostatismo (p<0.001). Il Transitional dyspnoea score è stato concordante con tali miglioramenti pur senza differenze significative tra i due gruppi. La TC del torace ha evidenziato una sopraelevazione dell’emidiaframma suturato, senza recidiva di ernia, mentre i pazienti sottoposti a plicatura hanno mantenuto l’ipercorrezione. Conclusioni. L’utilizzo di un rinforzo protesico è sicuro e sembra assicurare risultati funzionali migliori a distanza in termini di flussi respiratori e di movimento paradosso del diaframma (valutato mediante PImax). Lacerazioni estese del diaframma coinvolgenti le branche principali di suddivisione del nervo frenico si associano verosimilmente a una relaxatio che può quindi ridurre il guadagno funzionale a lungo termine se non adeguatamente trattata mediante l’utilizzo di un rinforzo protesico.

Preliminary results of an ICP-controlled subarachnoid hemorrhage rabbit model for the study of delayed cerebral vasospasm

INTRODUCTION: Intracisternal blood injection is the most common applied experimental subarachnoid bleeding technique in rabbits. The model comprises examiner-dependent variables and does not closely represent the human pathophysiological sequelae of ruptured cerebral aneurysm. The degree of achieved delayed cerebral vasospasm (DCVS) in this model is often mild. The aim of this study was to characterize and evaluate the feasibility of a clinically more relevant experimental SAH in vivo model. SAH was performed by arterial blood shunting from the subclavian artery into the great cerebral cistern. A total of five experiments were performed. Intracranial pressure (ICP), arterial blood pressure, heart rate, arterial blood gas analysis, and neurological status were monitored throughout the experiments. SAH induced vasoconstriction of the basilar artery was 52.1±3.4% on day 3 compared to baseline (P<0.05). Post-mortem gross examination of the brain showed massive blood clot accumulation around the brainstem and ventral surface of the brain. The novel technique offers an examiner independent SAH induction and triggers high degrees of delayed cerebral vasospasm. The severity of vasospasm attained offers a unique opportunity to evaluate future therapeutic treatment options.

Relationship of horse owner assessed respiratory signs index to characteristics of recurrent airway obstruction in two Warmblood families

REASONS FOR PERFORMING STUDY: The horse owner assessed respiratory signs index (HOARSI-1-4, healthy, mildly, moderately and severely affected, respectively) is based on owner-reported clinical history and has been used for the investigation of recurrent airway obstruction (RAO) genetics utilising large sample sizes. Reliable phenotype identification is of paramount importance in genetic studies. Owner reports of respiratory signs have shown good repeatability, but the agreement of HOARSI with an in-depth examination of the lower respiratory tract has not been investigated. OBJECTIVES: To determine the correlation of HOARSI grades 3/4 with the characteristics of RAO and of HOARSI-2 with the characteristics of inflammatory airway disease. Further, to test whether there are phenotypic differences in the manifestation of lung disease between families. METHODS: Seventy-one direct offspring of 2 RAO-affected Warmblood stallions (33 from the first family, 38 from the second) were graded as HOARSI-1-4 and underwent a clinical examination of the respiratory system, arterial blood gas analysis, endoscopic mucus scoring, cytology of tracheobronchial secretion (TBS) and bronchoalveolar lavage fluid (BALF), and clinical assessment of airway reactivity to methacholine chloride. RESULTS: HOARSI-3/4 animals in clinical exacerbation showed signs consistent with RAO: coughing, nasal discharge, abnormal lung sounds and breathing pattern as well as increased numbers of neutrophils in TBS and BALF, excessive mucus accumulation and airway hyper-responsiveness to methacholine. HOARSI-3/4 horses in remission only had increased amounts of tracheal mucus and TBS neutrophil percentages. Clinical phenotypes were not significantly different between the 2 families. CONCLUSIONS AND CLINICAL RELEVANCE: HOARSI reliably identifies RAO-affected horses in our population.

Acute hyponatremia after cardioplegia by histidine-tryptophane-ketoglutarate - a retrospective study

Background Hyponatremia is the most common electrolyte disorder in hospitalized patients and is known to be associated with increased mortality. The administration of antegrade single-shot, up to two liters, histidine-tryptophane-ketoglutarate (HTK) solution for adequate electromechanical cardiac arrest and myocardial preservation during minimally invasive aortic valve replacement (MIAVR) is a standard procedure. We aimed to determine the impact of HTK infusion on electrolyte and acid–base balance. Methods In this retrospective analysis we reviewed data on patient characteristics, type of surgery, arterial blood gas analysis during surgery and intra-/postoperative laboratory results of patients receiving surgery for MIAVR at a large tertiary care university hospital. Results A total of 25 patients were included in the study. All patients were normonatremic at start of surgery. All patients developed hyponatremia after administration of HTK solution with a significant drop of serum sodium of 15 mmol/L (p < 0.01). Measured osmolality did not change during all times of surgery compared to start of surgery (p = 0.28 – p = 0.79), indicating isotonic hyponatremia. After administration of HTK solution pH fell significantly due to development of metabolic acidosis. Conclusions Acute hyponatremia during cardioplegia with HTK solution is isotonic and should probably not be corrected without presence of hypotonicity as confirmed by measurement of serum osmolality.

Arterio-venous gradients of free energy change for assessment of systemic and splanchnic perfusion in cardiac surgery patients

OBJECTIVE: Adequacy of organ perfusion depends on sufficient oxygen supply in relation to the metabolic needs. The aim of this study was to evaluate the relationship between gradients of free energy change, and the more commonly used parameter for the evaluation of the adequacy of organ perfusion, such as oxygen-extraction in patients undergoing valve replacement surgery using normothermic cardiopulmonary bypass (CPB). METHODS: In 43 cardiac patients, arterial, mixed venous, and hepato-venous blood samples were taken synchronously after induction of anaesthesia (preCPB), during CPB, and 2 and 7 h after admission to the intensive care unit (ICU+2, ICU+7). Blood gas analysis, cardiac output, and hepato-splanchnic blood flow were measured. Free energy change gradients between mixed venous and arterial (-deltadeltaG(v - a)) and hepato-venous and arterial (-deltadeltaG(hv - a)) compartments were calculated. MEASUREMENTS AND RESULTS: Cardiac index (CI) increased from 1.9 (0.7) to 2.8 (1.3) L/min/m (median, inter-quartile range) (p = 0.001), and hepato-splanchnic blood flow index (HBFI) from 0.6 (0.22) to 0.8 (0.53) L/min/m (p = 0.001). Despite increasing flow, systemic oxygen extraction increased after CPB from 24 (10)% to 35 (10)% at ICU+2 (p = 0.002), and splanchnic oxygen extraction increased during CPB from 37 (19)% to 52 (14)% (p = 0.001), and remained high thereafter. After CPB, high splanchnic and systemic gradients of free energy change gradients were associated with high splanchnic and systemic oxygen extraction, respectively (p = 0.001, 0.033, respectively). CONCLUSION: Gradients of free energy change may be helpful in characterising adequacy of perfusion in cardiac surgery patients independently from measurements or calculations of data from oxygen transport.

Alternative protocol to initiate high-frequency oscillatory ventilation: an experimental study

INTRODUCTION: The objective was to study the effects of a novel lung volume optimization procedure (LVOP) using high-frequency oscillatory ventilation (HFOV) upon gas exchange, the transpulmonary pressure (TPP), and hemodynamics in a porcine model of surfactant depletion. METHODS: With institutional review board approval, the hemodynamics, blood gas analysis, TPP, and pulmonary shunt fraction were obtained in six anesthetized pigs before and after saline lung lavage. Measurements were acquired during pressure-controlled ventilation (PCV) prior to and after lung damage, and during a LVOP with HFOV. The LVOP comprised a recruitment maneuver with a continuous distending pressure (CDP) of 45 mbar for 2.5 minutes, and a stepwise decrease of the CDP (5 mbar every 5 minute) from 45 to 20 mbar. The TPP level was identified during the decrease in CDP, which assured a change of the PaO2/FIO2 ratio < 25% compared with maximum lung recruitment at CDP of 45 mbar (CDP45). Data are presented as the median (25th-75th percentile); differences between measurements are determined by Friedman repeated-measures analysis on ranks and multiple comparisons (Tukey's test). The level of significance was set at P < 0.05. RESULTS: The PaO2/FiO2 ratio increased from 99.1 (56.2-128) Torr at PCV post-lavage to 621 (619.4-660.3) Torr at CDP45 (CDP45) (P < 0.031). The pulmonary shunt fraction decreased from 51.8% (49-55%) at PCV post-lavage to 1.03% (0.4-3%) at CDP45 (P < 0.05). The cardiac output and stroke volume decreased at CDP45 (P < 0.05) compared with PCV, whereas the heart rate, mean arterial pressure, and intrathoracic blood volume remained unchanged. A TPP of 25.5 (17-32) mbar was required to preserve a difference in PaO2/FIO2 ratio < 25% related to CDP45; this TPP was achieved at a CDP of 35 (25-40) mbar. CONCLUSION: This HFOV protocol is easy to perform, and allows a fast determination of an adequate TPP level that preserves oxygenation. Systemic hemodynamics, as a measure of safety, showed no relevant deterioration throughout the procedure.

Influence of oxygen therapy on glucose-lactate metabolism after diffuse brain injury

OBJECT: Severe traumatic brain injury (TBI) imposes a huge metabolic load on brain tissue, which can be summarized initially as a state of hypermetabolism and hyperglycolysis. In experiments O2 consumption has been shown to increase early after trauma, especially in the presence of high lactate levels and forced O2 availability. In recent clinical studies the effect of increasing O2 availability on brain metabolism has been analyzed. By their nature, however, clinical trauma models suffer from a heterogeneous injury distribution. The aim of this study was to analyze, in a standardized diffuse brain injury model, the effect of increasing the fraction of inspired O2 on brain glucose and lactate levels, and to compare this effect with the metabolism of the noninjured sham-operated brain. METHODS: A diffuse severe TBI model developed by Foda and Maramarou, et al., in which a 420-g weight is dropped from a height of 2 m was used in this study. Forty-one male Wistar rats each weighing approximately 300 g were included. Anesthesized rats were monitored by placing a femoral arterial line for blood pressure and blood was drawn for a blood gas analysis. Two time periods were defined: Period A was defined as preinjury and Period B as postinjury. During Period B two levels of fraction of inspired oxygen (FiO2) were studied: air (FiO2 0.21) and oxygen (FiO2 1). Four groups were studied including sham-operated animals: air-air-sham (AAS); air-O2-sham (AOS); air-air-trauma (AAT); and air-O2-trauma (AOT). In six rats the effect of increasing the FiO2 on serum glucose and lactate was analyzed. During Period B lactate values in the brain determined using microdialysis were significantly lower (p < 0.05) in the AOT group than in the AAT group and glucose values in the brain determined using microdialysis were significantly higher (p < 0.04). No differences were demonstrated in the other groups. Increasing the FiO2 had no significant effect on the serum levels of glucose and lactate. CONCLUSIONS: Increasing the FiO2 influences dialysate glucose and lactate levels in injured brain tissue. Using an FiO2 of 1 influences brain metabolism in such a way that lactate is significantly reduced and glucose significantly increased. No changes in dialysate glucose and lactate values were found in the noninjured brain.

Influence of inspired oxygen on glucose-lactate dynamics after subdural hematoma in the rat

The mechanisms causing brain damage after acute subdural hematoma (SDH) are poorly understood. A decrease in cerebral blood flow develops immediately after the hematoma forms, thus reducing cerebral oxygenation. This in turn may activate mitochondrial failure and tissue damage leading to ionic imbalance and possibly to cellular breakdown. The purpose of this study was to test whether a simple therapeutic measure, namely increased fraction of inspired oxygen (FiO2 100), and hence increased arterial and brain tissue oxygen tension, can influence brain glucose and lactate dynamics acutely after subdural hematoma in the rat. Twenty-five male Sprague-Dawley anesthetized rats were studied before, during and after induction of the SDH in two separate groups. The Oxygen group (n = 10) was ventilated with 100% oxygen immediately after induction of the SDH. The Air group (n = 10) was ventilated during the entire study with 21% oxygen. Brain microdialysate samples were analyzed for glucose and lactate. All rats were monitored with femoral arterial blood pressure catheters, arterial blood gas analysis, arterial glucose, lactate and end tidal CO2 (EtCO2). Five male Sprague-Dawley rats were sham operated to measure the effect of oxygen challenge on glucose-lactate dynamics without injury. Arterial oxygen tension in the Oxygen group was 371 +/- 30 mmHg and was associated with significantly greater increase in dialysate lactate in the first 30 min after induction of SDH. Dialysate glucose initially dropped in both groups, after SDH, but then reverted significantly faster to values above baseline in the Oxygen group. Changes in ventilatory parameters had no significant effect on dialysate glucose and lactate parameters in the sham group. Extracellular dialysate lactate and glucose are influenced by administration of 100% O2 after SDH. Dialysate glucose normalizes significantly quicker upon 100% oxygen ventilation. We hypothesize that increased neural tissue oxygen tension, in presence of reduced regional CBF, and possibly compromised mitochondrial function, after acute SDH results in upregulation of rate-limiting enzyme systems responsible for both glycolytic and aerobic metabolism. Similar changes have been seen in severe human head injury, and suggest that a simple therapeutic measure, such as early ventilation with 100% O2, may improve cerebral energy metabolism, early after SDH. Further studies to measure the generation of adenosine triphosphate (ATP) are needed to validate the hypothesis.

THE POTENTIAL OF INDUSTRIAL WASTE AND AGRICULTURAL FEEDSTOCK TOWARDS SUSTAINABLE BIOFUELS PRODUCTION: TECHNO-ECONOMIC AND ENVIRONMENTAL IMPACT PERSPECTIVES

This Ph.D. research is comprised of three major components; (i) Characterization study to analyze the composition of defatted corn syrup (DCS) from a dry corn mill facility (ii) Hydrolysis experiments to optimize the production of fermentable sugars and amino acid platform using DCS and (iii) Sustainability analyses. Analyses of DCS included total solids, ash content, total protein, amino acids, inorganic elements, starch, total carbohydrates, lignin, organic acids, glycerol, and presence of functional groups. Total solids content was 37.4% (± 0.4%) by weight, and the mass balance closure was 101%. Total carbohydrates [27% (± 5%) wt.] comprised of starch (5.6%), soluble monomer carbohydrates (12%) and non-starch carbohydrates (10%). Hemicellulose components (structural and non-structural) were; xylan (6%), xylose (1%), mannan (1%), mannose (0.4%), arabinan (1%), arabinose (0.4%), galatactan (3%) and galactose (0.4%). Based on the measured physical and chemical components, bio-chemical conversion route and subsequent fermentation to value added products was identified as promising. DCS has potential to serve as an important fermentation feedstock for bio-based chemicals production. In the sugar hydrolysis experiments, reaction parameters such as acid concentration and retention time were analyzed to determine the optimal conditions to maximize monomer sugar yields while keeping the inhibitors at minimum. Total fermentable sugars produced can reach approximately 86% of theoretical yield when subjected to dilute acid pretreatment (DAP). DAP followed by subsequent enzymatic hydrolysis was most effective for 0 wt% acid hydrolysate samples and least efficient towards 1 and 2 wt% acid hydrolysate samples. The best hydrolysis scheme DCS from an industry's point of view is standalone 60 minutes dilute acid hydrolysis at 2 wt% acid concentration. The combined effect of hydrolysis reaction time, temperature and ratio of enzyme to substrate ratio to develop hydrolysis process that optimizes the production of amino acids in DCS were studied. Four key hydrolysis pathways were investigated for the production of amino acids using DCS. The first hydrolysis pathway is the amino acid analysis using DAP. The second pathway is DAP of DCS followed by protein hydrolysis using proteases [Trypsin, Pronase E (Streptomyces griseus) and Protex 6L]. The third hydrolysis pathway investigated a standalone experiment using proteases (Trypsin, Pronase E, Protex 6L, and Alcalase) on the DCS without any pretreatment. The final pathway investigated the use of Accellerase 1500® and Protex 6L to simultaneously produce fermentable sugars and amino acids over a 24 hour hydrolysis reaction time. The 3 key objectives of the techno-economic analysis component of this PhD research included; (i) Development of a process design for the production of both the sugar and amino acid platforms with DAP using DCS (ii) A preliminary cost analysis to estimate the initial capital cost and operating cost of this facility (iii) A greenhouse gas analysis to understand the environmental impact of this facility. Using Aspen Plus®, a conceptual process design has been constructed. Finally, both Aspen Plus Economic Analyzer® and Simapro® sofware were employed to conduct the cost analysis as well as the carbon footprint emissions of this process facility respectively. Another section of my PhD research work focused on the life cycle assessment (LCA) of commonly used dairy feeds in the U.S. Greenhouse gas (GHG) emissions analysis was conducted for cultivation, harvesting, and production of common dairy feeds used for the production of dairy milk in the U.S. The goal was to determine the carbon footprint [grams CO2 equivalents (gCO2e)/kg of dry feed] in the U.S. on a regional basis, identify key inputs, and make recommendations for emissions reduction. The final section of my Ph.D. research work was an LCA of a single dairy feed mill located in Michigan, USA. The primary goal was to conduct a preliminary assessment of dairy feed mill operations and ultimately determine the GHG emissions for 1 kilogram of milled dairy feed.

[Acute asthma attacks in childhood]

The diagnosis of an acute asthmatic attack in a child is made on a clinical basis. The severity of the exacerbation can be assessed by physical examination and measurement of the transcutaneous oxygenation saturation. A blood gas analysis can be helpful in this assessment. A child with a severe asthma exacerbation should be promptly referred to an emergency department of a hospital. Oxygen should be given to keep the oxygen saturation above 92% and short-acting, selective beta-2 agonists should be administered. Beta-2 agonists can be delivered by intermittent nebulization, continuous nebulization or by metered dose inhaler (MDI) with a spacer They can also be given intravenously in patients who are unresponsive to escalating therapy. The early administration of systemic corticosteroids is essential for the management of acute asthma in children. When tolerated, systemic corticoseroids can be given orally but inhaled corticosteroids are not recommended. Oxygen delivery, beta-2 agonists and steroid therapy are the mainstay of emergency treatment. Hypovolemia should be corrected either intravenously or orally. Administration of multiple doses of ipratropium bromide has been shown to decrease the hospitalization rate in children and adolescents with severe asthma. Clinical response to initial treatment is the main criterion for hospital admission. Patients with failure to respond to treatment should be transferred to an intensive care unit. A critical aspect of management of the acute asthma attack in a child is the prevention of similar attacks in the future.

Lactic acidosis following heart transplantation: a common phenomenon?

BACKGROUND Lactic acidosis (LAc) is a common form of metabolic acidosis early after heart transplantation (HTX). The mechanism remains unclear. This study analyzed 13 patients who developed severe LAc after HTX. METHODS From a series of 60 consecutive heart transplant patients, we identified 13 patients with LAc in the first hours following HTX. Nine patients with normal or mildly elevated lactate levels (<5.0 mmol/l) were investigated as controls. RESULTS Thirteen patients developed a moderate or severe LAc (up to 14.6 mmol/l) after HTX. Serum lactate levels increased immediately following surgery with a peak after 6.3+/-1.4 h, spontaneously returning to normal values within 24 h. In contrast to the control group, a significant correlation was found between the maximal serum lactate level and the maximal dosage of inotropic drugs (r=0.93, P<0.02), administered during the reperfusion phase and continued for 12-24 h postoperatively. No correlation was found between LAc and blood gas analysis during extracorporeal perfusion period. CONCLUSION LAc can occur after HTX and seems to be related to the inotropic support of the graft. In contrast to other forms, LAc after HTX has an excellent prognosis and resolves rapidly and spontaneously without treatment. The fact that inotropic support during and immediately after cardiac transplantation can enhance preexisting severe peripheral metabolic cellular dysfunction remains hypothetical.

Anaesthesia with medetomidine, midazolam and ketamine in six gorillas after premedication with oral zuclopenthixol dihydrochloride

OBJECTIVE To evaluate the effects of medetomidine, midazolam and ketamine (MMK) in captive gorillas after premedication with oral zuclopenthixol. STUDY DESIGN Case series. ANIMALS Six gorillas, two males and four females, aged 9-52 years and weighing 63-155 kg. METHODS The gorillas were given zuclopenthixol dihydrochloride 0.2 ± 0.05 mg kg(-1) per os twice daily for 3 days for premedication. On the day of anaesthesia the dose of zuclopenthixol was increased to 0.27 mg kg(-1) and given once early in the morning. Anaesthesia was induced with medetomidine 0.04 ± 0.004 mg kg(-1) , midazolam 0.048 ± 0.003 mg kg(-1) and ketamine 4.9 ± 0.4 mg kg(-1) intramuscularly (IM). Upon recumbency, the trachea was intubated and anaesthesia was maintained on 1-2% isoflurane in oxygen. Physiological parameters were monitored every 10 minutes and arterial blood gas analysis was performed once 30-50 minutes after initial darting. At the end of the procedure, 42-115 minutes after initial darting, immobilisation was antagonized with atipamezole 0.21 ± 0.03 mg kg(-1) and sarmazenil 5 ± 0.4 μg kg(-1) IM. RESULTS Recumbency was reached within 10 minutes in five out of six animals. One animal required two additional darts before intubation was feasible. Heart rate ranged from 60 to 85 beats minute(-1) , respiratory rate from 17 to 46 breaths minute(-1) and temperature from 36.9 to 38.3 °C. No spontaneous recoveries were observed and anaesthetic level was stable. Blood gas analyses revealed mild respiratory acidosis, and mean PaO(2) was 24.87 ± 17.16 kPa (187 ± 129 mmHg) with all values being above 13.4 kPa (101 mmHg). Recovery was smooth and gorillas were sitting within 25 minutes. CONCLUSION AND CLINICAL RELEVANCE The drug combination proved to be effective in anaesthetizing captive gorillas of various ages and both sexes, with minimal cardio-respiratory changes.

Effect of comprehensive cardiac rehabilitation after heart valve surgery (CopenHeartVR): study protocol for a randomised clinical trial

Background Heart valve diseases are common with an estimated prevalence of 2.5% in the Western world. The number is rising due to an ageing population. Once symptomatic, heart valve diseases are potentially lethal, and heavily influence daily living and quality of life. Surgical treatment, either valve replacement or repair, remains the treatment of choice. However, post surgery, the transition to daily living may become a physical, mental and social challenge. We hypothesise that a comprehensive cardiac rehabilitation programme can improve physical capacity and self-assessed mental health and reduce hospitalisation and healthcare costs after heart valve surgery. Methods A randomised clinical trial, CopenHeartVR, aims to investigate whether cardiac rehabilitation in addition to usual care is superior to treatment as usual after heart valve surgery. The trial will randomly allocate 210 patients, 1:1 intervention to control group, using central randomisation, and blinded outcome assessment and statistical analyses. The intervention consists of 12 weeks of physical exercise, and a psycho-educational intervention comprising five consultations. Primary outcome is peak oxygen uptake (VO2 peak) measured by cardiopulmonary exercise testing with ventilatory gas analysis. Secondary outcome is self-assessed mental health measured by the standardised questionnaire Short Form 36. Also, long-term healthcare utilisation and mortality as well as biochemistry, echocardiography and cost-benefit will be assessed. A mixed-method design is used to evaluate qualitative and quantitative findings encompassing a survey-based study before the trial and a qualitative pre- and post-intervention study. Discussion The study is approved by the local regional Research Ethics Committee (H-1-2011-157), and the Danish Data Protection Agency (j.nr. 2007-58-0015).

Hyperammonemic encephalopathy in multiple myeloma

HISTORY AND CLINICAL FINDINGS A 54-year old man had suffered from advanced multiple myeloma for two years. After initially good response the myeloma was refractrory to treatment with dexamethasone, cyclophosphamide, bortezomibe, zoledronate and additionally doxorubicine. The patient then complained of dyspnea without clinical signs of cardiopulmonary disease. INVESTIGATIONS Arterial blood gas analysis showed hyperventilation with respiratory alkalosis and normal alveolo-arterial gradient as the reason for the dyspnea. With a normal MRI of the brain and lumbal puncture, a neurological disease could be excluded. Serum calcium, creatinine and serum viscosity were normal. Eventually, serum ammonia levels were found to be substantially elevated (144 µmol/l) and hyperammonemic encephalopathy was diagnosed. TREATMENT AND COURSE Therapy with bortezomib and high dose dexamethason was repeated, and the patient also received bendamustin. Despite this treatment, he lost consciousness and died after two weeks because of aspiration pneumonia. CONCLUSION The existence of respiratory alkalosis and multiple myeloma should prompt a search for hyperammonemia.