[Mediocarpal instability of the wrist]. / Mediokarpale Instabilitäten der Handwurzel.

Typical lesions of the carpal ligaments are mostly found after a fall on the wrist in hyperextension or as complex injuries after severe trauma, e. g. after a fall from a significant height, motorcycle accident or as accompanying lesions in multiple trauma. The typical mechanisms, patterns and diagnostic algorithms are well known for the common ligamentous injuries (e.g. scapholunate, lunotriquetral and perilunate); therefore, consistent diagnostic procedures and adequate therapy are increasingly performed after such lesions, e. g. by early ligament repair or by ligament reconstruction through augmentation. Within appropriate operative treatment, accompanying fractures are also treated and instabilities are addressed by transfixation of joints by Kirschner wires. If followed by immobilization with a cast or stable brace, healing can be achieved in most cases; however, more problems occur if ligamentous lesions or instabilities are not clearly due to a trauma mechanism and more the result of laxity or hypermobile situations due to a congenital predisposition. In such cases, wrist pain is often described and misdiagnosed as the result of overload or tenovaginitis.

Acute adrenal insufficiency: an aide-memoire of the critical importance of its recognition and prevention.

Adrenal crisis is a life-threatening emergency that causes significant excess mortality in patients with adrenal insufficiency. Delayed recognition by medical staff of an impending adrenal crisis and failure to give timely hydrocortisone therapy within the emergency department continue to be commonly encountered, even in metropolitan teaching hospitals. Within the authors' institutions, several cases of poorly handled adrenal crises have occurred over the last 2 years. Anecdotal accounts from members of the Addison's support group suggest that these issues are common in Australia. This manuscript is a timely reminder for clinical staff on the critical importance of the recognition, treatment and prevention of adrenal crisis. The manuscript: (i) outlines a case and the clinical outcome of sub-optimally managed adrenal crisis, (ii) summarises the clinical features and acute management of adrenal crisis, (iii) provides recommendations on the prevention of adrenal crisis and (iv) provides guidance on the management of 'sick days' in patients with adrenal insufficiency.

Effects of a coccidiosis challenge on dietary methionine recommendations in broilers.

Broilers are commonly exposed to coccidiosis infections, and the use of dietary strategies to reduce losses in growth performance has practical implications for the poultry industry. Methionine (Met) is typically the first limiting amino acid for broilers and is involved in metabolic and immunological pathways; however, literature is conflicting on how dietary Met requirements are affected by environmental stressors. Our objective was to assess how the Met requirement changes during coccidiosis based on results of growth performance, carcass traits, and health outcomes. Two trials were conducted using 780 male Ross 308 broiler chicks in floor pens randomly assigned to 1 of 12 experimental treatments. All birds received common starter (d 0-10) and finisher (d 24-35, Trial 2 only) diets, and only differed based on their assigned experimental grower diet (d 10-24). Trial 1 experimental grower diets ranged from 2.61 to 6.21 g/kg digestible Met. Trial 2 experimental grower diets were formulated to contain 15% below, at, or 15% above the Met requirement determined in Trial 1. Birds were exposed to a coccidiosis challenge on d 11, with blood and tissue collection (1 bird/pen) on d 18 and carcass processing on d 35 (2 birds/pen) in Trial 2. Data were analyzed using a 1- or 2-way ANOVA. A non-linear regression analysis was conducted in Trial 1 to determine the Met requirement of 4.32 g of digestible Met/kg of diet using BW gain. Coccidiosis infection reduced (P < 0.05) growth performance during the experimental grower and overall study periods in Trial 2. Increasing dietary Met from below requirement to meeting requirement during the grower period improved (P < 0.001) BW gain and feed conversion ratio (FCR), but this effect was only significant between treatments below and above the requirement for the overall study period. There was an interactive effect (P = 0.038) on FCR for the overall study period. These findings provide evidence that the Met requirement is likely increased during coccidiosis based on growth performance outcomes.

Defining optimal dietary starch, oil, and amino acid inclusion levels for broilers experiencing a coccidiosis challenge.

Alternative methods to alleviate coccidiosis in broilers are of interest to producers, including dietary strategies to minimize disruptions in growth rate and efficiency when faced with health challenges. Our objective was to determine optimal combinations of dietary starch, amino acids (AA), and oil to benefit productivity of broilers experiencing Eimeria-induced immune activation. Two trials were conducted using 1,536 male Ross 308 broiler chicks in floor pens randomly assigned to 1 of 17 experimental treatments. All birds received common starter (d 0-10) and finisher (d 24-35) diets, and only differed based on their assigned experimental grower diet (d 10-24). Trial 1 experimental grower diets ranged from 2,700 to 3,300 kcal/kg AME. Trial 2 included 10 experimental grower diets following a simplex lattice design consisting of 3 basal lots formulated to have the highest starch (45.4%), oil (10.2%), or AA density (120, 1.33% digestible Lys) and mixed in 4 equally spaced levels for each component (0, 0.33, 0.67, 1). These mixtures enabled varying densities of AA (80-120% of recommendation), starch:oil (4:1-20:1), and AME (2,940-3,450 kcal/kg). Bird and feeder weights were collected on d 0, 10, 24, and 35, and birds were exposed to an Eimeria challenge on d 11 or 12. In trial 2, excreta samples were collected for AME determination and carcasses were processed on d 36. Data were analyzed using ANOVA, t test, or regression. In Trial 1, BW gain and feed conversion were improved (P < 0.05) by increasing dietary AME. In Trial 2, birds receiving diets containing AA at 93 to 107% of recommendations and higher oil exhibited improved (P < 0.05) performance, but increased starch at the expense of oil reduced performance (P < 0.05). Relative breast and fat pad weights were not influenced by diet in Trial 2. We determined that broilers mildly challenged with Eimeria would exhibit highest BW gain when receiving diets containing 35.8% starch, 8.9% oil, and 101.3% of AA recommendations, which can be utilized by producers to maintain productivity under health-challenged conditions.

[Skeletal tuberculosis of the distal radius during pregnancy]. / Ossäre Tuberkulose am distalen Radius in der Schwangerschaft.

We present a case of a pregnant woman (32nd gestational week) that suffered from a chronic non-healing wound at the distal radius. Skeletal tuberculosis was finally diagnosed and treated successfully with staged surgical therapy combined with appropriate medication. One year after surgical treatment, the outcome of the mother was excellent and the baby did not suffer from any disease related to operative procedures or pharmacotherapy. Operative treatment of skeletal tuberculosis (especially osteoarticular and vertebral tuberculosis) in combination with tuberculostatic therapy during pregnancy and lactation seem to be the appropriate treatment with minimal risk for the child and excellent outcome for the mother.

Rise of extremity fractures and sport accidents in children at 8-12 years and increase of admittance via the resuscitation room over a decade.

INTRODUCTION: In an emergency department, the majority of pediatric trauma patients present because of minor injuries. The aim of this study was to evaluate temporal changes in age-related injury pattern, trauma mechanism, and surgeries in pediatric patients. METHODS: This retrospective study included patients < 18 years of age following trauma from 01/2009 to 12/2018 at a level I trauma center. They were divided into two groups: group A (A: 01/2009 to 12/2013) and group B (B: 01/2014 to 12/2018). Injury mechanism, injury pattern, and surgeries were analyzed. As major injuries fractures, dislocations, and organ injuries and as minor injuries contusions and superficial wounds were defined. RESULTS: 23,582 patients were included (58% male, median age 8.2 years). There was a slight increase in patients comparing A (n = 11,557) and B (n = 12,025) with no difference concerning demographic characteristics. Significant more patients (A: 1.9%; B: 2.4%) were admitted to resuscitation room, though the number of multiple injured patients was not significantly different. In A (25.5%), major injuries occurred significantly less frequently than in B (27.0%), minor injuries occurred equally. Extremity fractures were significantly more frequent in B (21.5%) than in A (20.2%), peaking at 8-12 years. Most trauma mechanisms of both groups were constant, with a rising of sport injuries at 8-12 years. CONCLUSION: Although number of patients increases only slightly over a decade, there was a clear increase in major injuries, particularly extremity fractures, peaking at 8-12 years. At this age also sport accidents significantly increased. At least, admittance to resuscitation room rose but without an increase of multiple injured patients.

[Orbital and intracranial complications of acute sinusitis. Diagnostics and therapy in children and adolescents]. / Orbitale und intrakranielle Komplikationen akuter Sinusitiden. Diagnostik und Therapie bei Kindern und Jugendlichen.

Orbital and intracranial complications of acute sinusitis occur more frequently in the pediatric population compared to adults due to anatomic differences. Since the introduction of antibiotics the frequency of such complications has been dramatically reduced. Nevertheless, even in the era of modern antibiotics these complications continue to occur and it is therefore of utmost importance not only to know about these complications but also to include them in the differential diagnosis. Appropriate diagnosis mainly based on CT scanning or magnetic resonance tomography is the basis for a rapid and sufficient and if necessary interdisciplinary treatment. In this CME article the diagnostic and therapeutic interventions in four young patients suffering from orbital or intracranial complications due to acute sinusitis are described and discussed in the context of the current literature and a clinical algorithm is introduced.

Correction of Motion Artifacts Using a Multiscale Fully Convolutional Neural Network.

BACKGROUND AND PURPOSE: Motion artifacts are a frequent source of image degradation in the clinical application of MR imaging (MRI). Here we implement and validate an MRI motion-artifact correction method using a multiscale fully convolutional neural network. MATERIALS AND METHODS: The network was trained to identify motion artifacts in axial T2-weighted spin-echo images of the brain. Using an extensive data augmentation scheme and a motion artifact simulation pipeline, we created a synthetic training dataset of 93,600 images based on only 16 artifact-free clinical MRI cases. A blinded reader study using a unique test dataset of 28 additional clinical MRI cases with real patient motion was conducted to evaluate the performance of the network. RESULTS: Application of the network resulted in notably improved image quality without the loss of morphologic information. For synthetic test data, the average reduction in mean squared error was 41.84%. The blinded reader study on the real-world test data resulted in significant reduction in mean artifact scores across all cases (P < .03). CONCLUSIONS: Retrospective correction of motion artifacts using a multiscale fully convolutional network is promising and may mitigate the substantial motion-related problems in the clinical MRI workflow.

[Actively living a medical safety (error) culture-what does urology need to learn?] / Gelebte Sicherheits(fehler)kultur ­ was muss die Urologie lernen?

Patient safety is the basic quality of every medical treatment. Scientifically sound knowledge on the necessary structures of a safety management system and experience from effectively implementing those are aplenty. Yet, even 30 years after the first successful steps, it is still difficult for healthcare to implement a comprehensive, system-wide approach. Cultural changes at the level of attitudes and the consistent creation of the necessary structures might accelerate this transformation process.

Oxidative stress markers in young hemodialysis patients - a pilot study.

AIMS: Studies in young hemodialysis patients without significant comorbidities might increase the understanding of incipient vascular pathology in uremia. We investigated whether a specific pattern of oxidative stress markers with potential prognostic significance could be identified in this population. MATERIAL AND METHODS: We performed a cross-sectional matched case control study of 25 young hemodialysis patients (age 18 - 40 years) without known comorbidity factors. Patients were matched pairwise to healthy controls, and markers of oxidative stress were analyzed for associations with surrogate parameters of vascular structure and function. RESULTS: Oxidized low-density lipoproteins (OxLDL) were similar in patients and controls whereas conjugated dienes were increased in the very low-density lipoproteins (VLDL) fraction (20 +/- 6 vs. 12 +/- 5 micromol/l, p < 0.0001), but not in the low-density lipoproteins (LDL) fraction (16 +/- 6 vs. 18 +/- 6 micromol/l). Superoxide dismutase (SOD) activity was diminished in patients (1,117 +/- 151 vs. 1,299 +/- 88 U/g Hb, p < 0.0001), but there was no difference in glutathione peroxidase (GPx) activity. Oxidative stress expressed as the ratio of oxidized and reduced glutathione (GSSG/GSH) was increased in patients (0.25 +/- 0.18 vs. 0.13 +/- 0.04, p = 0.0048). Intima-media thickness (IMT) of the common carotid artery (0.70 +/- 0.12 vs. 0.62 +/- 0.08 mm, p = 0.0007) was significantly increased, and postischemic peak flow (PIPF) by venous occlusion plethysmography was severely diminished in patients (632 +/- 319 vs. 1,057 +/- 543% of basal flow, p < 0.0001). None of the markers of oxidative stress was independently associated with IMT or PIPF or a significant discriminator between patients and controls by multivariate regression. CONCLUSIONS: In this pilot study of exclusively young patients on hemodialysis, oxidative stress markers were of limited clinical value in identifying young patients at risk for vascular complications.

A simulation platform using 3D printed neurovascular phantoms for clinical utility evaluation of new imaging technologies.

Modern 3D printing technology allows rapid prototyping of vascular phantoms based on an actual human patient with a high degree of precision. Using this technology, we present a platform to accurately simulate clinical views of neuro-endovascular interventions and devices. The neuro-endovascular interventional phantom has a 3D printed cerebrovasculature model derived from a patient CT angiogram and embedded inside a human skull providing bone attenuation. Acrylic layers were placed underneath and on top of the skull, simulating entrance and exit tissue attenuation and also simulating forward scatter. The 3D model was connected to a pulsatile flow loop for simulating interventions using clinical devices such as catheters and stents. To validate the x-ray attenuation and establish clinical accuracy, the automatic exposure selection by a clinical c-arm system for the phantom was compared with that for a commercial anthropomorphic head phantom (SK-150, Phantom Labs). The percentage difference between automatic exposure selection for the neuro-intervention phantom and the SK-150 phantom was under 10%. By changing 3D printed models, various patient diseased anatomies can be simulated accurately with the necessary x-ray attenuation. Using this platform various interventional procedures were performed using new imaging technologies such as a high-resolution x-ray fluoroscope and a dose-reduced region-of-interest attenuator and differential temporally filtered display for enhanced interventional imaging. Simulated clinical views from such phantom-based procedures were used to evaluate the potential clinical performance of such new technologies.

Clinical outcome after alternative treatment of scaphoid fractures and nonunions.

PURPOSE: Achieving stable fixation of scaphoid fractures and nonunions continues to be a challenge. Compression screw fixation has been the current standard surgical procedure. However, in some cases, bone healing cannot be achieved and requires further revision. Recent series reintroduced volar plating as valid option for stable fixation. The aim of the study was to review clinical outcome of alternative scaphoid treatment. METHODS: From 2011 to 2014, nine patients with scaphoid fracture were treated by Headless Compression Screw (HCS) and seven patients with scaphoid nonunion by HCS or volar mini condylar plate with bone graft. The average age was 34.4 years and the average time to follow-up was 19.3 months. From 1996 to 1998, 38 patients with scaphoid nonunion were treated using compression screw (S-group) or volar mini condylar plate (P-group) with bone graft. The average age was 39.6 years and the average time to follow-up was 26.2 months. RESULTS: The union rate was 100%. For scaphoid fractures, the mean Modified Mayo Wrist Score (MMWS) was 94.1 and the DASH score 7.4. From 2011 to 2014, the MMWS was 87.9 and the DASH score 7 in scaphoid nonunions. In the period between 1996 and 1998, the MMWS was 67.2 in the P-group and 58.6 in the S-group, and the DASH score 16.8 and 28.2. CONCLUSIONS: Our study demonstrated that appropriate application of the HCS was able to produce very satisfactory results in scaphoid fractures and nonunions. In our opinion, however, the method of scaphoid plate osteosynthesis can achieve a higher degree of stability, particularly rotational stability, in case of multifragmentary avascular scaphoid nonunions.

[The use of the flexible laryngeal mask in children with adenoidectomy--a retrospective comparison with endotracheal intubation]. / Die Anwendung der Spiral-Larynxmaske zur Adenotomie bei Kindern--Ein retrospektiver Vergleich zur Intubationsnarkose.

BACKGROUND: While adenoidectomy in childhood is a standard procedure, different alternatives of airway and anaesthesiologic management are discussed. Therefore we investigated retrospectively paediatric anaesthesias with laryngeal mask (LMA) or endotracheal intubation (ITN) during adenoidectomies in our department of otorhinolaryngology. METHODS: A retrospective analysis of 385 anaesthesia records of the last three years was performed. Variables were age and weight of the children, anaesthetics, surgical procedures, size of LMA, recovery time, anaesthesiological complications as well as the incidence of abandoning the laryngeal mask in favour of a tracheal intubation. RESULTS: Recovery time was significantly reduced (3.63 min) in LMA group compared to ITN group (p < 0.001). Complications did not arise more frequently in the LMA group. LMA had to be changed into ITN in 11 cases (5,6 %) only. CONCLUSION: Our study shows the LMA being a safe and effective alternative to ITN in airway treatment of children undergoing adenoidectomy.

[Avulsion injuries of the anterior inferior iliac spine among soccer players--a differential diagnosis to neoplasm decades following the trauma]. / Avulsionsverletzungen der Spina iliaca anterior inferior bei Fussballern - eine Differenzialdiagnose zum Neoplasma Jahrzehnte nach einem Trauma.

Pelvic apophyseal injuries typically involve adolescents, ranging gradually from apophysitis as a chronic traction injury to avulsion fractures after a sudden contraction of a muscle to the immature musculo-skeleton adolescent. While avulsion fractures to the anterior superior iliac spine, the iliac crest and the pubic bone are common, injuries to the anterior inferior iliac spine (AIIS) are only rarely encountered. We report on two 42 and 43-year old male soccer players complaining of groin pain. Both had AIIS avulsion fractures diagnosed by conventional plain x-ray of the pelvis, ultrasound and magnetic resonance imaging. One patient had an acute adductor longus muscle injury with concomitant asymptomatic AIIS avulsion fracture. Conservative treatment of the muscle injury with initial RICE therapy followed by pain-restricted jogging brought him back to sport within four weeks. The other patient had local tenderness and exercise pain at AIIS with a large exostosis on imaging studies mimicking a pseudotumor. Surgical resection was applied and the rectus femoris muscle was reattached. After three months of intensive physical therapy he could be return to sport. Avulsion fractures of the AIIS may cause persistent pain syndrome and mimic a pseudotumor decades after the initial trauma, which can be treated by surgical resection and reattachment of the rectus femoris muscle with good results. Conservative treatment for minor dislocated AIIS avulsion fractures can be effective in sportsmen. Differential diagnosis often involves bony tumors, so patient's soccer history gives important information regarding past avulsion fractures of the pelvis, which often occur during kicking in the adolescence.

Towards predicting the encoding capability of MR fingerprinting sequences.

Sequence optimization and appropriate sequence selection is still an unmet need in magnetic resonance fingerprinting (MRF). The main challenge in MRF sequence design is the lack of an appropriate measure of the sequence's encoding capability. To find such a measure, three different candidates for judging the encoding capability have been investigated: local and global dot-product-based measures judging dictionary entry similarity as well as a Monte Carlo method that evaluates the noise propagation properties of an MRF sequence. Consistency of these measures for different sequence lengths as well as the capability to predict actual sequence performance in both phantom and in vivo measurements was analyzed. While the dot-product-based measures yielded inconsistent results for different sequence lengths, the Monte Carlo method was in a good agreement with phantom experiments. In particular, the Monte Carlo method could accurately predict the performance of different flip angle patterns in actual measurements. The proposed Monte Carlo method provides an appropriate measure of MRF sequence encoding capability and may be used for sequence optimization.

Prolonged high-pressure treatments in mammalian skeletal muscle result in loss of functional sodium channels and altered calcium channel kinetics.

Activation and inactivation of ion channels involve volume changes from conformational rearrangements of channel proteins. These volume changes are highly susceptible to changes in ambient pressure. Depending on the pressure level, channel function may be irreversibly altered by pressure. The corresponding structural changes persist through the post-decompression phase. High-pressure applications are a useful tool to evaluate the pressure dependence as well as pressure limits for reversibility of such alterations. Mammalian cells are only able to tolerate much lower pressures than microorganisms. Although some limits for pressure tolerance in mammalian cells have been evaluated, the mechanisms of pressure-induced alteration of membrane physiology, in particular of channel function, are unknown. To address this question, we recorded fast inward sodium (I(Na)) and slowly activating L-type calcium (I(Ca)) currents in single mammalian muscle fibers in the post-decompression phase after a prolonged 3-h, high-pressure treatment of up to 20 MPa. I(Na) and I(Ca) peak amplitudes were markedly reduced after pressure treatment at 20 MPa. This was not from a general breakdown of membrane integrity as judged from in situ high-pressure fluorescence microscopy. Membrane integrity was preserved even for pressures as high as 35 MPa at least for pressure applications of shorter durations. Therefore, the underlying mechanisms for the observed amplitude reductions have to be determined from the activation (time-to-peak [TTP]) and inactivation (tau(dec)) kinetics of I(Na) and I(Ca). No major changes in I(Na) kinetics, but marked increases, both in TTP and tau(dec) for I(Ca), were detected after 20 MPa. The apparent molecular volume changes (activation volumes) deltaV(double dagger) for the pressure-dependent irreversible alteration of channel gating approached zero for Na+ channels. For Ca2+ channels, deltaV(double dagger) was very large, with approx 2.5-fold greater values for channel activation than inactivation (approx 210 A3). We conclude, that in skeletal muscle, high pressure differentially and irreversibly affects the gating properties and the density of functional Na+ and Ca2+ channels. Based on these results, a model of high pressure-induced alterations to the channel conformation is proposed.

High energy probe for detecting lymph node metastases with 18F-FDG in patients with head and neck cancer.

AIM: of this study was to validate a newly developed high energy probe (positron emission probe, PEP) optimised for localising PET tracers in vivo. PATIENTS AND METHODS: Physical investigations included determination of full width at half maximum (FWHM) values at a distance of 1 cm and angular resolution using different point sources. Values obtained with the new probe were compared to those of a conventional gamma probe (CGP). Additionally, PET studies were performed in 36 patients (6 women, 30 men) with proven head and neck cancer and suspected lymph node metastases (Axis, Marconi/Philips) after administering 250-320 MBq (18)F-FDG. Subsequent to PET investigations (18)F-FDG uptake in cervical regions was measured using the PEP. PEP investigations were carried out bilaterally in 5 lymph node (LN) levels (Robbins' classification of the neck). Results of probe studies were correlated with visual and semiquantitative PET evaluations, US and histological findings. RESULTS: FWHM of the new probe was 7 mm (CGP 22 mm) at 662 keV ((137)Cs) and angular resolution resulted in 8 degrees (CGP 60 degrees ). In 29 out of 36 patients LN metastases were suspected due to ultrasound investigations. After neck dissection, histology confirmed LN metastases in 21 patients. Sensitivity (sens.) of US amounted to 95% and specificity to 40%. In 18/21 patients LN metastases were detected by PET (sens. 86%). PET scans failed to diagnose the LN status correctly in 6/36 patients (accuracy 83%). Employing the PEP probe in 20/21 patients LN metastases were identified (sens. 95%), and LN status was determined accurately in 29/36 patients (accuracy 81%). Tumour/background ratios of PEP measurement and results of semiquantitative PET analyses were comparable. CONCLUSIONS: PEP measurement is a promising method for preoperative planning of the extent of neck dissection in patients with head and neck cancer and further for radioguided localising PET tracer accumulation during surgery.

[Squamous cell carcinoma of the conjunctiva with orbital invasion: orbital exenteration or minimally invasive procedure?]. / Plattenepithelkarzinom der Bindehaut mit Orbitainvasion : Exenteratio orbitae oder minimal-invasives Vorgehen?

BACKGROUND: Here we present a case of a female patient with squamous cell carcinoma with orbital invasion who insisted on a globe-sparing excisional biopsy rather than a more invasive procedure. CASE: A 48-year-old patient presented with a conjunctival tumor at the medial canthus of the right eye. The visual acuity in this eye was 1.0. MRI showed a 25 mm x 12 mm tumor, with orbital invasion, no metastasis, but on CT scan damage of the lamina papyracea was suspected. Histology of a punch biopsy confirmed a moderately differentiated, squamous cell carcinoma. As requested by the patient, simple tumor excision with a 5-mm safety margin, reconstruction of the lower fornix with amniotic membrane, and adjuvant mitomycin C therapy were performed. Intraoperatively the medial orbital wall was found to be intact. No local or systemic recurrence has occurred 3.5 years postoperatively. The patient's VA is still 1.0; no visual field defects are detectable, and there are only minor upper lid levator restriction and diplopia in maximum upgaze. CONCLUSION: In view of this case the choice of surgical treatment for malignant tumors of the conjunctiva with orbital invasion - between exenteration or a minimally invasive procedure - should be carefully discussed with the patient. A follow-up of 5 years is strongly recommended.

'In situ' high pressure confocal Ca(2+)-fluorescence microscopy in skeletal muscle: a new method to study pressure limits in mammalian cells.

We combined 'in situ' high pressure microscopy with confocal laser scanning microscopy to directly study Ca2+ homeostasis in intact mammalian (murine) skeletal muscle fibres during high pressure exposure up to 35 MPa. Cytosolic Fluo-4 and mitochondrial Rhod-2 Ca2+ fluorescence were simultaneously monitored. To separate changes in Ca2+ and direct/indirect effects of pressure on the dye, experiments in permeabilized ('skinned') muscle fibres were performed at a fixed Ca2+ concentration. Normalized Fluo-4 fluorescence sharply declined up to 10 MPa but showed a plateau between 10 MPa and -35 MPa. In the intact fibre, Fluo-4 fluorescence exponentially decreased during pressurization to 35 MPa with a pressure constant of pi-5 MPa whereas mitochondrial Rhod-2 fluorescence exponentially increased with a four-fold larger pi. Holding the pressure at 35 MPa almost did not change Fluo-4 fluorescence. However, Rhod-2 fluorescence started to decrease after -40 min. Upon decompression, Rhod-2 and Fluo-4 fluorescence increased exponentially with similar pi. However, initial Fluo-4 fluorescence values were not restored. Our results are in agreement with pressure induced Ca2+ leakage from the sarcoplasmic reticulum. Ca2+ might then be taken up in large amounts by mitochondria preventing cytosolic increase in Ca2+. Prolonged pressure applications (-40 min at 35 MPa) seem to destabilize mitochondrial function with release of Ca2+ from mitochondria back into the cytosol and eventually mechanical activation resulting in irreversible contractures. The pressure induced disturbance of Ca2+ homeostasis might have important implications for the pressure exposure limits and/or dive profiles of deep sea mammals.