Amitriptyline accumulation in tissues after coated activated charcoal hemoperfusion-a randomized controlled animal poisoning model

Amitriptyline poisoning (AT) is a common poisoning, and AT possess the ability to promote life-threatening complications by its main action on the central nervous and cardiovascular systems. The pharmacokinetic properties might be altered at toxic levels compared to therapeutic levels. The effect of coated activated charcoal hemoperfusion (CAC-HP) on the accumulation of AT and its active metabolite nortriptyline (NT) in various tissues was studied in a non-blinded randomized controlled animal trial including 14 female Danish Land Race piglets. All piglets were poisoned with amitriptyline 7.5 mg/kg infused in 20 min, followed by orally instilled activated charcoal at 30 min after infusion cessation. The intervention group received 4 h of CAC-HP followed by a 1-h redistribution phase. At study cessation, the piglets were euthanized, and within 20 min, vitreous fluid, liver tissue, ventricle and septum of the heart, diaphragm and lipoic and brain tissues were collected. AT and NT tissue concentrations were quantified by UHPLC-MS/MS. A 4-h treatment with CAC-HP did not affect the tissue accumulation of AT in the selected organs when tested by Mann-Whitney U test (p values between 0.44 and 0.73). For NT concentrations, p values were between 0.13 and 1.00. Although not significant, an interesting finding was that data showed a tendency of increased tissue accumulation of AT and NT in the CAC-HP group compared with the control group. Coated activated charcoal hemoperfusion does not significantly alter the tissue concentration of AT and NT in the AT-poisoned piglet.

Sphenopalatine Ganglion Stimulation to Augment Cerebral Blood Flow

Background and Purpose—

Many patients with acute ischemic stroke are not eligible for thrombolysis or mechanical reperfusion therapies due to contraindications, inaccessible vascular occlusions, late presentation, or large infarct core. Sphenopalatine ganglion (SPG) stimulation to enhance collateral flow and stabilize the blood-brain barrier offers an alternative, potentially more widely deliverable, therapy.

Methods—

In a randomized, sham-controlled, double-masked trial at 41 centers in 7 countries, patients with anterior circulation ischemic stroke not treated with reperfusion therapies within 24 hours of onset were randomly allocated to active SPG stimulation or sham control. The primary efficacy outcome was improvement beyond expectations on the modified Rankin Scale of global disability at 90 days (sliding dichotomy), assessed in the modified intention-to-treat population. The initial planned sample size was 660 patients, but the trial was stopped early when technical improvements in device placement occurred, so that analysis of accumulated experience could be conducted to inform a successor trial.

Results—

Among 303 enrolled patients, 253 received at least one active SPG or sham stimulation, constituting the modified intention-to-treat population (153 SPG stimulation and 100 sham control). Age was median 73 years (interquartile range, 64–79), 52.6% were female, deficit severity on the National Institutes of Health Stroke Scale was median 11 (interquartile range, 9–15), and time from last known well median 18.6 hours (interquartile range, 14.5–22.5). For the primary outcome, improved 3-month disability beyond expectations, rates in the SPG versus sham treatment groups were 49.7% versus 40.0%; odds ratio, 1.48 (95% CI, 0.89–2.47); P =0.13. A significant treatment interaction with stroke location (cortical versus noncortical) was noted, P =0.04. In the 87 patients with confirmed cortical involvement, rates of improvement beyond expectations were 50.0% versus 27.0%; odds ratio, 2.70 (95% CI, 1.08–6.73); P =0.03. Similar response patterns were observed for all prespecified secondary efficacy outcomes. No differences in mortality or serious adverse event safety end points were observed.

Conclusions—

SPG stimulation within 24 hours of onset is safe in acute ischemic stroke. SPG stimulation was not shown to statistically significantly improve 3-month disability above expectations, though favorable outcomes were nominally higher with SPG stimulation. Beneficial effects may distinctively be conferred in patients with confirmed cortical involvement. The results of this study need to be confirmed in a larger pivotal study.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03767192.

Effects of low-dose recombinant human erythropoietin treatment on cognitive performance

INTRODUCTION

High-dose recombinant human erythropoietin (rhEpo) has been shown to improve cognitive performance in both healthy volunteers and in patients suffering from diseases affecting the brain. The aim of this study was to examine whether administration of low-dose and even micro-dose rhEpo improves cognitive performance in healthy volunteers.

METHODS

We enrolled 25 healthy volunteers in a double-blind, randomised, placebo-controlled study to receive either low-dose rhEpo (n = 8, 60 IU/kg/week), micro-dose rhEpo (n = 9, 20 IU/kg/week), or saline (n = 8) for four weeks. Two cognitive performance-tests, the Raven Standard Progressive Matrices (Raven) and the Number Finder (NUFI), were performed during the first and last day of the study period. Semi-structured interviews were conducted weekly and were coded according to a scale.

RESULTS

Subjects receiving micro-dose rhEpo improved significantly measured by the Raven score (p = 0.04), and subjects receiving low-dose rhEpo treatment improved significantly measured by the NUFI score (p = 0.047), whereas no improvement was found in experienced cognitive performance in any of the groups. We found no significant difference in either Raven, NUFI or self-reported results between the groups.

CONCLUSIONS

In this small study, we found no significant effect of low-dose or micro-dose rhEpo on visual attention, cognitive performance in complex cognitive tasks or self-experienced cognitive performance compared with placebo.

FUNDING

The Aase and Ejnar Danielsen's Foundation. Danish Ministry of Science, Innovation and Higher Education.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03093506.

A clinical study of short-term sternal photoplethysmography: Recordings from patients with obstructive airways diseases

Traditionally, measurements of the oxygen saturation (S_pO₂) has been confound to the extremities. In this study, we therefore investigated the possibility for reliable estimation of clinically relevant S_pO₂ levels from photoplethysmography (PPG) obtained on the sternum of patients with obstructive airway diseases. We initiated the study with a calibration of a prototype sternal PPG sensor. In accordance with the ISO 80601-2-61:2011 guidelines, the calibration was conducted as a controlled desaturation study. We obtained a calibration accuracy of 1.75% which is well within the clinically and commercially accepted range. We then compared the S_pO₂ levels simultaneously obtained from the sternal PPGs and a commercially available finger pulse oximeter on 28 admitted patients with either asthma or Chronic Obstructive Pulmonary Disease (COPD). The Pearson correlation between the S_pO₂ levels estimated from the two body locations was found to be 0.89 (p<;0.05) and the mean system bias was only 0.052% with upper and lower limits of agreement of 2.5% and -2.4%, respectively. This finding is very promising for the future design of new sternum based patch technologies that might be able to provide continuous estimates of the S_pO₂ levels on critically or chronically ill patients.

Activated Charcoal Haemoperfusion in the Treatment of Experimental Amitriptyline Poisoning in Pigs - The Effect on Amitriptyline Plasma Concentration and Haemodynamic Parameters

Coated activated charcoal haemoperfusion (CAC-HP) is a well-known treatment modality. Case reports have revealed conflicting results about the efficacy of CAC-HP in the treatment of amitriptyline (AT) poisoning, and no randomized clinical trials have been identified in the literature. This study aimed at quantifying the efficacy of modern CAC-HP as an adjunctive treatment of AT intoxication compared with standard care alone. Fourteen female Danish landrace pigs were randomized to either standard care or standard care plus 4 hr of CAC-HP. The pigs were anaesthetized, and vital parameters were continuously recorded. Amitriptyline infusion (7.5 mg/kg) was completed in 20 min. Thirty minutes after AT infusion, activated charcoal was instilled orally in both groups. In the intervention group, CAC-HP was initiated 60 min. after AT infusion. Blood and urine samples were collected as were vital parameters at specific time intervals. The protocol was approved by the Danish Experimental Animal Expectorate and complied with the NIH guide for care and use of laboratory animals. Data were managed according to the ARRIVE guidelines. No statistical significant differences between intervention and control groups were found when analysing for differences in AT levels in plasma at any time-point. Furthermore, significant differences between the control and intervention groups in regard to vital parameters could not be found either. In our animal model, the addition of CAC-HP did not improve the clearance of AT compared with standard treatment alone. We suggest that the effect of modern CAC-HP as a treatment modality in AT-poisoned human patients may be inadequate.

Estimation of respiratory rates based on photoplethysmographic measurements at the sternum

The respiratory rate (RR) is a clinically important vital sign and is a frequently used parameter in the general hospital wards. In current clinical practice, the monitoring of the RR is by manual count of the chest movement for one minute. This paper addresses a new approach where the respiratory rate is extracted using photoplethysmography (PPG) on the chest bone (sternum). Sternal PPG signals were acquired from 10 healthy subjects resting in a supine position. As reference signals, finger PPG, electrocardiogram (ECG), and capnography were simultaneously recorded during spontaneous and paced breathing. The sternal PPG signals were then compared with the reference signals in terms of Bland-Altman analysis, the power spectrum analysis and the magnitude squared coherence. The Bland-Altman analysis showed an average bias of 0.21 breaths/min between RR extracted from sternal PPG and capnography. The respiratory power content at the sternum was 78.8 (38) % in terms of the median and (the interquartile range). The cardiac content was 19 (18.4) % within the cardiac region. The results from the magnitude squared coherence analysis was 0.97 (0.09) in the respiratory region (6 to 27 breaths/min) and 0.98 (0.01) in the cardiac pulse region (30-120 beats/min). This preliminary study demonstrates the possibility of monitoring the RR from sternal PPG on a healthy group of subjects during rest.

Preoperative steroid in abdominal wall reconstruction: protocol for a randomised trial

INTRODUCTION

Preoperative administration of high-dose glucocorticoid leads to improved recovery and decreased length of stay after abdominal surgery. Even so, studies on administration of glucocorticoids for patients undergoing abdominal wall reconstruction (AWR) for giant ventral hernia repair are lacking, perhaps due to a fear of impaired wound healing. We hypothesised that patients undergoing AWR would benefit from preoperative glucocorticoids and aimed at examining this in a randomised controlled trial.

METHODS

A total of 40 patients scheduled to undergo AWR for ventral hernias with a fascial defect exceeding 10 cm will be randomised for intravenous administration of either 125 mg methylprednisolone or saline at the induction of anaesthesia. The primary endpoint is pain at rest on the first post-operative day. Patients will be followed until 30 days post-operatively, and secondary outcomes include subjective measures, wound complications and analysis of blood and wound fluids.

CONCLUSIONS

This is the first trial on the effect of preoperative glucocorticoid administration in patients undergoing AWR. Due to long post-operative stays and a high rate of post-operative complications, this patient group can potentially benefit much from any post-operative optimisation. Furthermore, insight into any impact of glucocorticoids on wound healing in hernia patients may provide important information.

FUNDING

none.

TRIAL REGISTRATION

This study was registered with Clinicaltrials.gov (NCT02594241) and Eudra-CT (2015-004916-39).

Long-term quasi-continuous oxygen saturation levels obtained from sternal photoplethysmography on patients with obstructive lung diseases

Calculation of long-term quasi-continuous oxygen saturation (SpO2) levels is highly relevant for critically ill patients. The purpose of this study is therefore to conduct a preliminary investigation of the clinical reliability of long-term photoplethysmography (PPG) recordings obtained from the sternum of patients admitted to the hospital with obstructive lung diseases. Due to the lack of a gold standard reference that is suitable for long-term monitoring without interfering with the patient's activity level, we extracted reliable segments based on knowledge from the basic pulse oximeter theory as well as knowledge about the inherent physiological regulation of the SpO2 levels. We included 15 admitted patients who were monitored with a prototype of a sternal PPG sensor for approximately 20 hours. On average, we found that clinically reliable SpO2 levels could be calculated for 58% of the recording time. Furthermore, the average and standard deviation of the longest period of time with unreliable data was only 23.6 ± 19.38 minutes. This indicates a high potential for quasi-continuous calculation of SpO2 levels from sternal PPGs in many different clinical applications in the future.

Repeated treatments of drooling with botulinum toxin B in neurology

OBJECTIVES

To investigate efficacy, saliva flow, and composition in repeated BoNT-B treatments of drooling.

MATERIALS AND METHODS

Seventeen neurological patients (median 66 years), referred for treatment of drooling participated in this observational study. Median total doses of 4000 units botulinum toxin type B (BoNT-B, Neurobloc(®)) were injected with at least 3 months intervals into parotid and submandibular glands using ultrasound guidance. Measures of drooling and saliva collection for analysis were obtained before treatment, and 6, 12, and eventually 18 weeks after.

RESULTS

Number of treatment series in each patient was 1-7. Compared to baseline, saliva flow rate and drooling were reduced 30-70% 6 weeks after treatment in the first series, while sodium, chloride, and total protein increased 20-80% (t-tests; P < 0.05). After 12 weeks, drooling was still significantly reduced, saliva flow tended to be, and saliva composition was back to baseline. Frequent side effects were viscous saliva and dry mouth. Due to fading effect in eight patients, individual decisions were taken to change from BoNT-B to BoNT-A. Similarly, the outcome was significantly reduced over time in six patients completing five subsequent BoNT-B treatment series (ANOVA; P < 0.05).

CONCLUSION

In the first series, BoNT-B treatment resulted in marked reduction of drooling and saliva flow rate with some relapse after 12 weeks. The viscous saliva was ascribed to increased total protein content and compensatory mechanisms related to ß-adrenergic receptor-specific actions. With patients needing long-term treatment, it should be noted that the efficacy of repeated BoNT-B may fade with time.

Sternal pulse rate variability compared with heart rate variability on healthy subjects

The heart rate variability (HRV) is a commonly used method to quantify the sympathetic and the parasympathetic modulation of the heart rate. HRV is mainly conducted on electrocardiograms (ECG). However, the use of photo-plethysmography (PPG) as a marker of the autonomic tone is emerging. In this study we investigated the feasibility of deriving pulse rate variability (PRV) using PPG signals recorded by a reflectance PPG sensor attached to the chest bone (sternum) and comparing it to HRV. The recordings were conducted on 9 healthy subjects being in a relaxed supine position and under forced respiration, where the subjects were asked to breathe following a visual scale with a rate of 27 breaths/min. HRV parameters such as the mean intervals (meanNN), the standard deviation of intervals (SDNN), the root mean square of difference of successive intervals (RMSSD), and the proportion of intervals differing more than 50 ms (pNN50) were calculated from the R peak-to-R peak (R-R) and pulse-to-pulse (P-P) intervals. In the frequency domain the low and high frequency ratio of the power spectral density (LF/HF) was also computed. The Pearson correlation coefficient showed significant correlation for all the parameters (r > 0.95 with p < 0.001) and the Bland-Altmann analysis showed close agreement between the two methods for all the parameters during resting and forced respiration condition. Thus, PRV analysis using sternal PPG can be an alternative to HRV analysis on healthy subjects at.

Procedure for calculation of potency and efficacy for ligands acting on Gs- and Gi-coupled receptors

Structure activity relationship (SAR) analyses of pharmacological data of compounds constitute an important part of the discovery process in the design of new drug candidates with improved pharmacological properties. In particular G-Protein Coupled Receptors (GPCRs) associated with the cAMP second messenger systems G(s) and G(i) have constituted one of the most widely used basis for pharmacological in vitro assays for assessing functional receptor effects. Such assays are based on Radio Immuno Assay (RIA) analysis to measure the cellular cAMP concentration as readout of receptor activation. It appears, however, to be a common practice to omit the use of cAMP standard curves to transform the measured signals (cpm or cps) into cAMP concentrations on which estimations of potencies (EC(50) values) and efficacies (E(MAX) values) in G(s) and G(i) coupled receptor stimulation are based. Such practice may lead to significant errors as compounds mediating their effects via G(s) coupled receptors may appear more potent and efficacious than they actually are. Contrary, compounds mediating their effects via G(i) coupled receptors may appear less potent and efficacious than they are in reality. Potency rank orders will therefore change considerably, when estimations are based on incorrect calculation of the original experimental results. Thus, the only correct way to calculate effect data on which to base E(MAX) and EC(50) estimations is to use cAMP concentrations derived from transformation of the measured signals (cpm or cps) using cAMP standard curves. The present work outlines the mathematical procedures by which such transformations are to be performed.

Which goal for fluid therapy during colorectal surgery is followed by the best outcome: near-maximal stroke volume or zero fluid balance?

BACKGROUND

We aimed to investigate whether fluid therapy with a goal of near-maximal stroke volume (SV) guided by oesophageal Doppler (ED) monitoring result in a better outcome than that with a goal of maintaining bodyweight (BW) and zero fluid balance in patients undergoing colorectal surgery.

METHODS

In a double-blinded clinical multicentre trial, 150 patients undergoing elective colorectal surgery were randomized to receive fluid therapy after either the goal of near-maximal SV guided by ED (Doppler, D group) or the goal of zero balance and normal BW (Zero balance, Z group). Stratification for laparoscopic and open surgery was performed. The postoperative fluid therapy was similar in the two groups. The primary endpoint was postoperative complications defined and divided into subgroups by protocol. Analysis was performed by intention-to-treat. The follow-up was 30 days. The trial had 85% power to show a difference between the groups.

RESULTS

The number of patients undergoing laparoscopic or open surgery and the patient characteristics were similar between the groups. No significant differences between the groups were found for overall, major, minor, cardiopulmonary, or tissue-healing complications (P-values: 0.79; 0.62; 0.97; 0.48; and 0.48, respectively). One patient died in each group. No significant difference was found for the length of hospital stay [median (range) Z: 5.00 (1-61) vs D: 5.00 (2-41); P=0.206].

CONCLUSIONS

Goal-directed fluid therapy to near-maximal SV guided by ED adds no extra value to the fluid therapy using zero balance and normal BW in patients undergoing elective colorectal surgery.

Erythropoietin treatment enhances muscle mitochondrial capacity in humans

Erythropoietin (Epo) treatment has been shown to induce mitochondrial biogenesis in cardiac muscle along with enhanced mitochondrial capacity in mice. We hypothesized that recombinant human Epo (rhEpo) treatment enhances skeletal muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity in humans. In six healthy volunteers rhEpo was administered by sub-cutaneous injection over 8 weeks with oral iron (100 mg) supplementation taken daily. Mitochondrial OXPHOS was quantified by high-resolution respirometry in saponin-permeabilized muscle fibers obtained from biopsies of the vastus lateralis before and after rhEpo treatment. OXPHOS was determined with the mitochondrial complex I substrates malate, glutamate, pyruvate, and complex II substrate succinate in the presence of saturating ADP concentrations, while maximal electron transport capacity (ETS) was assessed by addition of an uncoupler. rhEpo treatment increased OXPHOS (from 92 ± 5 to 113 ± 7 pmol·s⁻¹·mg⁻¹) and ETS (107 ± 4 to 143 ± 14 pmol·s⁻¹·mg⁻¹, p < 0.05), demonstrating that Epo treatment induces an upregulation of OXPHOS and ETS in human skeletal muscle.

An Electronic Patch for wearable health monitoring by reflectance pulse oximetry

We report the development of an Electronic Patch for wearable health monitoring. The Electronic Patch is a new health monitoring system incorporating biomedical sensors, microelectronics, radio frequency (RF) communication, and a battery embedded in a 3-dimensional hydrocolloid polymer. In this paper the Electronic Patch is demonstrated with a new optical biomedical sensor for reflectance pulse oximetry so that the Electronic Patch in this case can measure the pulse and the oxygen saturation. The reflectance pulse oximetry solution is based on a recently developed annular backside silicon photodiode to enable low power consumption by the light emitting components. The Electronic Patch has a disposable part of soft adhesive hydrocolloid polymer and a reusable part of hard polylaurinlactam. The disposable part contains the battery. The reusable part contains the reflectance pulse oximetry sensor and microelectronics. The reusable part is 'clicked' into the disposable part when the patch is prepared for use. The patch has a size of 88 mm by 60 mm and a thickness of 5 mm.

Ultrasound-guided bilateral dual transversus abdominis plane block: a new four-point approach

BACKGROUND

We describe a new ultrasound-guided bilateral dual transversus abdominis plane block. Our hypothesis was that we could anaesthetize both the upper (Th6-Th9) and the lower (Th10-Th12) abdominal wall bilaterally using a four-point single-shot technique to provide effective post-operative analgesia.

METHODS

A prospective cohort of 25 recovery room patients was included. They had undergone major open or laparoscopic abdominal surgery under general anaesthesia and had severe post-operative pain. The blocks were conducted using a high-frequency linear transducer and a 22 G, 80-mm-long needle. The needle was inserted in-plane from medial to lateral for each injection. Fifteen millilitres of bupivacaine 2.5 mg/ml was injected at each of the four sites.

RESULTS

Block performance took on average 16 min (range 10-20 min). The 25 patients reported a reduction of their maximum pain (visual analogue scale 0-10) from a mean of 8.2 to a mean of 2.2 10 min after block performance (P<0.001). They were discharged from the post-anaesthesia care unit after an average of 34 min. Twenty-one patients (84%) did not require any i.v. opioids in the following 6 h. Sixteen patients (64%) were mobilized within 6 h after the block. Data were similar irrespective of open or laparoscopic surgery (P=0.68).

CONCLUSION

This new four-point single-shot technique was effective in decreasing severe pain after a major abdominal surgery. The block, although short-lived, facilitated discharge from the post-anaesthesia care unit, few patients required opioids on the day of surgery and mobilization was improved.

Nurse-administered early warning score system can be used for emergency department triage

INTRODUCTION

Studies have shown that early warning score systems can identify in-patients at high risk of catastrophic deterioration and this may possibly be used for an emergency department (ED) triage. Bispebjerg Hospital has introduced a multidisciplinary team (MT) in the ED activated by the Bispebjerg Early Warning Score (BEWS). The BEWS is calculated on the basis of respiratory frequency, pulse, systolic blood pressure, temperature and level of consciousness. The aim of this study is to evaluate the ability of the BEWS to identify critically ill patients in the ED and to examine the feasibility of using the BEWS to activate an MT response.

MATERIAL AND METHODS

This study is based on an evaluation of retrospective data from a random sample of 300 emergency patients. On the basis of documented vital signs, a BEWS was calculated retrospectively. The primary end points were admission to an intensive care unit (ICU) and death within 48 hours of arrival at the ED. This study was registered at clinicaltrials.gov (NCT01243021).

RESULTS

A BEWS ≥ 5 is associated with a significantly increased risk of ICU admission within 48 hours of arrival (relative risk (RR) 4.1; 95% confidence interval (CI) 1.5-10.9) and death within 48 hours of arrival (RR 20.3; 95% CI 6.9-60.1). The sensitivity of the BEWS in identifying patients who were admitted to the ICU or who died within 48 hours of arrival was 63%. The positive predictive value of the BEWS was 16% and the negative predictive value 98% for identification of patients who were admitted to the ICU or who died within 48 hours of arrival.

CONCLUSION

The BEWS is a simple scoring system based on readily available vital signs. It is a sensitive tool for detecting critically ill patients and may be used for ED triage and activation of an MT response.

Low compliance with a validated system for emergency department triage

INTRODUCTION

Bispebjerg Hospital has introduced a triage system at the Emergency Department (ED) based on "primary criteria" and a physiological scoring system named the Bispebjerg Early Warning Score (BEWS). A BEWS is calculated on the basis of five vital signs which are accessible bedside. Patients who have a "primary criterion" or a BEWS ≥ 5 are presumed to be critically ill or severely injured and should be received by a multidisciplinary team, termed the Emergency Call (EC) and Trauma Call (TC), respectively. The aim of this study was to examine compliance with this triage system at Bispebjerg Hospital.

MATERIAL AND METHODS

Retrospective evaluation of the triage of a random sample of 300 ED patients. ED medical charts were searched for "primary criteria", documentation of vital signs and a BEWS score. If a BEWS score had not been calculated, this was done retrospectively by the author. An evaluation was made to determine whether ECs or TCs had been correctly activated.

RESULTS

In 47 patients, all five vital signs for calculation of a BEWS had been documented. A BEWS had been calculated in 22 patients. Nine patients had a TC activation criterion, and in all these cases a TC was activated. A total of 48 patients had an EC activation criterion, but an EC had only been activated in 24 patients. Among the 24 patients for whom an EC had not been activated, eight had a "primary criterion" and 16 patients had a retrospective BEWS ≥ 5.

CONCLUSION

The triage system is not being used systematically and documentation of vital signs is insufficient at Bispebjerg Hospital. As a consequence, many patients who are presumed to be critically ill are not allocated to an EC. Initiatives have been taken to raise compliance with the system.

High-dose inhaled salbutamol has no acute effects on aerobic capacity or oxygen uptake kinetics in healthy trained men

The prevalence of asthma is higher among elite athletes than in the general population. This has resulted in the frequent use of anti-asthmatic medication such as beta2-agonists among asthmatic athletes. Beta2-agonists are on the prohibited list of WADA. The use of the beta2-agonist salbutamol is only permitted in therapeutic inhaled doses. Most studies have reported the lack of ergogenic effects of therapeutic doses of inhaled beta2-agonists measured in maximal oxygen uptake. No previous studies have examined any possible effects of high-dose inhaled salbutamol on oxygen uptake kinetics. We enrolled nine healthy well-trained men in a randomized, blinded, placebo-controlled crossover study. Subjects were randomized to inhalation of 40 puffs of 0.2 mg salbutamol or two placebo tablets and performed an incremental test to exhaustion and three submaximal tests at 75% of peak power to determine oxygen uptake kinetics. During the incremental test, there were no effects of inhaled salbutamol on VO(2max) in absolute or relative terms, and no effect on peak power and lactate threshold. During the submaximal test, we found no effects on the time constant, time delay, the mean response time or O(2) deficit related to oxygen uptake kinetics. In conclusion, no ergogenic effect of a high dose of salbutamol on aerobic capacity was found.

Early osteoarthritis and microdialysis: a novel in vivo approach for measurements of biochemical markers in the perisynovium and intraarticularly

The microdialysis technique was evaluated as a possible method to obtain local measurements of biochemical markers from knee joints with degenerative changes. Seven patients scheduled for arthroscopy of the knee due to minor to moderate degenerative changes had microdialysis catheters inserted under ultrasonographic guidance, intraarticularly and in the synovium-close tissue. Catheters were perfused at a rate of 2 μl/min for approximately 100 min with a Ringer solution containing radioactively labeled glucose, and the positions of the catheters were later visualized during arthroscopy. All intraarticular catheters and 6/7 subsynovial catheters were positioned correctly. Relative recovery (RR) was intraarticularly 0.64 ± 0.02 (mean ± SEM) and synovium-close 0.54 ± 0.06. Mean values of cartilage oligomeric matrix protein (COMP), aggrecan and glucosyl-galactosyl-pyridinoline in the intraarticular dialysates were 18.1 ± 7.0 U/l, 243.6 ± 108.6 ng/ml and 108.0 ± 29.0 pmol/ml, respectively. COMP and glucosyl-galactosyl-pyridinoline concentrations were significantly higher intraarticularly compared to perisynovial tissue (P < 0.05), whereas for aggrecan, no significant difference was found (P = 0.06). The microdialysis method can be used for intraarticular and subsynovial determination of metabolites in human knees at these sites. The present methodology displays a potential for future studies of simultaneous biochemical changes within and around joints.

Illusory sensation of movement induced by repetitive transcranial magnetic stimulation

Human movement sense relies on both somatosensory feedback and on knowledge of the motor commands used to produce the movement. We have induced a movement illusion using repetitive transcranial magnetic stimulation over primary motor cortex and dorsal premotor cortex in the absence of limb movement and its associated somatosensory feedback. Afferent and efferent neural signalling was abolished in the arm with ischemic nerve block, and in the leg with spinal nerve block. Movement sensation was assessed following trains of high-frequency repetitive transcranial magnetic stimulation applied over primary motor cortex, dorsal premotor cortex, and a control area (posterior parietal cortex). Magnetic stimulation over primary motor cortex and dorsal premotor cortex produced a movement sensation that was significantly greater than stimulation over the control region. Movement sensation after dorsal premotor cortex stimulation was less affected by sensory and motor deprivation than was primary motor cortex stimulation. We propose that repetitive transcranial magnetic stimulation over dorsal premotor cortex produces a corollary discharge that is perceived as movement.

Independent component analysis applied to pulse oximetry in the estimation of the arterial oxygen saturation (SpO2)--a comparative study

We examine various independent component analysis (ICA) digital signal processing algorithms for estimating the arterial oxygen saturation (SpO2) as measured by a reflective pulse oximeter. The ICA algorithms examined are FastICA, Maximum Likelihood ICA (ICAML), Molgedey and Schuster ICA (ICAMS), and Mean Field ICA (ICAMF). The signal processing includes pre-processing bandpass filtering to eliminate noise, and post-processing by calculating the SpO2. The algorithms are compared to the commercial state-of-the-art algorithm Discrete Saturation Transform (DST) by Masimo Corporation. It is demonstrated that ICAMS and ICAMF perform up to 13% better than DST. PPG recordings are done with a reflective pulse oximetry sensor integrated in an Electronic Patch. This system is intended for patients with chronic heart and lung conditions.

Voluntary respiratory control and cerebral blood flow velocity upon ice-water immersion

INTRODUCTION

In non-habituated subjects, cold-shock response to cold-water immersion causes rapid reduction in cerebral blood flow velocity (approximately 50%) due to hyperventilation, increasing risk of syncope, aspiration, and drowning. Adaptation to the response is possible, but requires several cold immersions. This study examines whether thorough instruction enables non-habituated persons to attenuate the ventilatory component of cold-shock response.

METHODS

There were nine volunteers (four women) who were lowered into a 0 degrees C immersion tank for 60 s. Middle cerebral artery mean velocity (CBFV) was measured together with ventilatory parameters and heart rate before, during, and after immersion.

RESULTS

Within seconds after immersion in ice-water, heart rate increased significantly from 95 +/- 8 to 126 +/- 7 bpm (mean +/- SEM). Immersion was associated with an elevation in respiratory rate (from 12 +/- 3 to 21 +/- 5 breaths, min(-1)) and tidal volume (1022 +/- 142 to 1992 +/- 253 ml). Though end-tidal carbon dioxide tension decreased from 4.9 +/- 0.13 to 3.9 +/- 0.21 kPa, CBFV was insignificantly reduced by 7 +/- 4% during immersion with a brief nadir of 21 +/- 4%.

DISCUSSION

Even without prior cold-water experience, subjects were able to suppress reflex hyperventilation following ice-water immersion, maintaining the cerebral blood flow velocity at a level not associated with impaired consciousness. This study implies that those susceptible to accidental cold-water immersion could benefit from education in cold-shock response and the possibility of reducing the ventilatory response voluntarily.

[Changes in blood profiles during Tour de France 2007]

INTRODUCTION

Marked changes in different blood variables, e.g. hemoglobin concentration ([Hb]) and hematocrit (Hct), are indications of blood manipulation. Blood sampling and the development of individual, longitudinal blood profiles have therefore been implemented in doping control in different sports federations.

MATERIALS AND METHODS

During the Tour de France 2007, 7 riders were randomly tested on 3 different occasions; the day before the prologue, and 12 and 19 days after the prologue. Blood was drawn into 3 mL EDTA covered tubes and kept at 4 degrees Celsius. They were analyzed within 24 hours on a Sysmex R-500.

RESULTS

[Hb] and Hct were significantly lower on day 12 (p = 0.005) and day 19 (p < 0.001) compared to baseline. All 7 riders had lower [Hb] and Hct on day 19 compared to baseline, while this was the case in 6 out of 7 riders already on day 12. The [Hb] and Hct were 11.5% and 12.1% lower on day 19 compared to baseline.

CONCLUSION

We observed significant decreases in [Hb] and Hct in 7 riders during Tour de France 2007. Whether or not this is due to decrease in hemoglobin mass or hemodilution, or the latter solely, increases in [Hb] and Hct during prolonged stage racing seem unphysiological and should therefore lead to further examination of the rider.

Blood profiles in elite cross-country skiers: a 6-year follow-up

Following the doping scandals at the World Championships in cross-country skiing in 2001, the International Ski Federation decided to generate individual blood profiles. From 2001 to 2007, 7081 blood samples from 1074 male and female elite cross-country skiers were collected and analyzed for hemoglobin concentration [Hb] and % reticulocytes (%rets). Data were applied to blood algorithms wherefrom blood model scores were calculated. From 1997-1999 to 2001-2002, the mean [Hb] was reduced by 0.9 g/dL to 15.3 g/dL in male skiers and by 0.4 g/dL to 13.8 in female skiers. From 2002-2003 to 2006-2007, the combination of increases in [Hb] and decreases in %rets led to pronounced increases in mean OFF-model scores. [Hb] was 0.2 g/dL higher at Olympic Games/World Championships (WOCs) than at World Cups competitions <4 weeks before and after WOCs. [Hb] and %rets increased with altitude in both genders. Since the introduction of an enlarged blood testing program, the mean [Hb] values were lowered to close to normal levels, but over the last 2-3 years there has been a small elevation and an increase in OFF-model scores, which may indicate a change in the manipulations used to elevate the [Hb].

[A 48-year-old woman's survival from a massive verapamil overdose]

We present a case report of survival from a massive verapamil overdose. The patient, a 48-year-old female, was admitted 12 hours after suicidal ingestion of 10.08 grams of Isoptin Retard, a sustained release calcium channel blocker. On admittance, the patient had altered mental status, was hypotensive, and ECG showed bradycardia with nodal rhythm. The patient was treated with activated charcoal, colloids, crystalloids, norepinephrine, isoprenalin and epinephrine infusion, high dose glucose-insulin infusion and calcium. The patient was discharged for rehabilitation after two weeks.

[Pathophysiology in accidental hypothermia. Hypothermia is not only a cold body]

Knowledge of the pathophysiology in accidental hypothermia is essential for clinical decision-making. The prognosis should be favourable provided the condition is recognized and treated accordingly. Progressive organ dysfunction is associated with a declining core temperature which is reversible on rewarming. Other reactions occur during rewarming of which rewarming collapse has received much attention. More detailed knowledge of rewarming collapse which has come out is examined in this paper.

Influence of upper body position on middle cerebral artery blood velocity during continuous positive airway pressure breathing

Continuous positive airway pressure (CPAP) is a treatment modality for pulmonary oxygenation difficulties. CPAP impairs venous return to the heart and, in turn, affects cerebral blood flow (CBF) and augments cerebral blood volume (CBV). We considered that during CPAP, elevation of the upper body would prevent a rise in CBV, while orthostasis would challenge CBF. To determine the body position least affecting indices of CBF and CBV, the middle cerebral artery mean blood velocity (MCA V(mean)) and the near-infrared spectroscopy determined frontal cerebral hemoglobin content (cHbT) were evaluated in 11 healthy subjects during CPAP at different body positions (15 degrees head-down tilt, supine, 15 degrees, 30 degrees and 45 degrees upper body elevation). In the supine position, 10 cmH(2)O of CPAP reduced MCA V(mean) by 9 +/- 3% and increased cHbT by 4 +/- 2 micromol/L (mean +/- SEM); (P < 0.05). In the head-down position, CPAP increased cHbT to 13 +/- 2 micromol/L but left MCA V(mean) unchanged. Upper body elevation by 15 degrees attenuated the CPAP associated reduction in MCA V(mean) (-7 +/- 2%), while cHbT returned to baseline (1 +/- 2 micromol/L). With larger elevation of the upper body MCA V(mean) decreased progressively to -17 +/- 3%, while cHbT remained unchanged from baseline. These results suggest that upper body elevation by approximately 15 degrees during 10 cmH(2)O CPAP prevents an increase in cerebral blood volume with minimal effect on cerebral blood flow.

[Cricoid pressure a.m. Sellick in rapid sequence intubation?]

Since Brian Sellick introduced the cricoid pressure in 1961, it has become standard practice for the rapid sequence intubation. The manoeuvre has a high priority and is recommended maintained even during difficult intubation. In this review the lack of evidence for the aspiration-reducing effect of cricoid pressure is discussed. The findings suggest that it may have harmful effects in connection with intubation, laryngeal mask placement and ventilation. In conclusion, it is suggested that cricoid pressure is released in the case of intubation difficulties.

Reduced cerebral perfusion on sudden immersion in ice water: a possible cause of drowning

INTRODUCTION

Near-drowning incidents and drowning deaths after accidental immersion in open waters have been linked to cold shock response. It consists of inspiratory gasps, hyperventilation, tachycardia, and hypertension in the first 2-3 min of cold-water immersion. This study explored the immediate changes in cerebral blood flow velocity (Vmean) during cold-water immersion since cold shock induced hyperventilation may diminish Vmean and lead to syncope and drowning.

METHODS

There were 13 male volunteers who were lowered into a 0 degrees C immersion tank for 30 s. Vmean in the middle cerebral artery (MCA) was measured together with ventilatory parameters and heart rate before, during, and after immersion.

RESULTS

Within seconds after immersion in ice water, heart rate increased from 74 +/- 16 to 107 +/- 18 bpm (mean +/- SD; p < 0.05). Immersion was associated with a marked elevation in respiratory rate (from 16 +/- 3 to 38 +/- 14 breaths x min(-1)) and tidal volume (883 +/- 360 to 2292 +/- 689 ml). The end-tidal carbon dioxide tension decreased from 38 +/- 4 to 26 +/- 5 mmHg and MCA Vmean dropped by 43 +/- 8%. Signs of imminent syncope (drowsiness, blurred vision, loss of responsiveness) were shown by two subjects (MCA Vmean dropped 62% and 68%, respectively).

DISCUSSION

Following ice-water immersion, hyperventilation induced a marked reduction in MCA Vmean to a level which has been associated with disorientation and loss of consciousness.

[Survival in cold water. Physiological consequences of accidental immersion in cold water]

This survey addresses the immediate physiological reactions to immersion in cold water: cold shock response, diving reflex, cardiac arrhythmias and hypothermia. Cold shock response is the initial sympathetic reaction to immersion in cold water. The diving reflex is elicited by submersion of the face. Afferent and efferent nerves are the trigeminal and vagal nerves. Cardiac arrhythmias occur immediately after immersion. If the immersion persists, hypothermia becomes an issue. Hypothermia is delayed by habituation to immersion in cold water as well as insulating garments, subcutaneous fat and a large lean body mass.

[Prolonged survival after accidental immersion in cold water]

In a recent boat accident, a 25-year-old yachting enthusiast fell overboard and survived for 24 hours in 17 degrees C water. Existing survival models are discussed in this case report. There is a discrepancy regarding survival probability amongst the various models. The calculated survival time for the yachtsman ranges from 3 hours to more than 30 hours. A reliable survival-time model is needed to determine the appropriate search duration of rescue services. In this case, the majority of the models underestimated the actual survival time.

Water transport by Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS). The dependence of substrate size studied at high resolution

The relation between substrate and water transport was studied in Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS) expressed in Xenopus oocytes. The water transport was monitored from changes in oocyte volume at a resolution of 20 pl, more than one order of magnitude better than previous investigations. The rate of cotransport was monitored as the clamp current obtained from two-electrode voltage clamp. The high resolution data demonstrated a fixed ratio between the turn-over of the cotransporter and the rate of water transport. This applied to experiments in which the rate of cotransport was changed by isosmotic application of substrate, by rapid changes in clamp voltage, or by poisoning. Transport of larger substrates gave rise to less water transport. For the rabbit SGLT1, 378+/-20 (n=18 oocytes) water molecules were cotransported along with the 2 Na+ ions and the glucose-analogue alpha-MDG (MW 194); using the larger sugar arbutin (MW 272) this number was reduced by a factor of at least 0.86+/-0.03 (15). For the human SGLT1 the respective numbers were 234+/-12 (18) and 0.85+/-0.8 (7). For NIS, 253+/-16 (12) water molecules were cotransported for each 2 Na+ and 1 thiocyanate (SCN-, MW 58), with I- as anion (MW 127) only 162+/-11 (19) water molecules were cotransported. The effect of substrate size suggests a molecular mechanism for water cotransport and is opposite to what would be expected from unstirred layer effects. Data were analysed by a model which combined cotransport and osmosis at the membrane with diffusion in the cytoplasm. The combination of high resolution measurements and precise modelling showed that water transport across the membrane can be explained by cotransport of water in the membrane proteins and that intracellular unstirred layers effects are minute.

Clinical evaluation of the lateral sagittal infraclavicular block developed by MRI studies

BACKGROUND AND OBJECTIVES

Lateral sagittal infraclavicular block by single injection has a faster performance time and causes less discomfort than does axillary block by multiple injections. This prospective, descriptive, multicenter study assessed block effectiveness, onset time, and incidence of adverse events and verified the noninvasive measurements from magnetic resonance imaging (MRI).

METHODS

One hundred sixty patients were anesthetized by use of the lateral sagittal infraclavicular block and following the MRI recommendations for needle insertion. Each patient received a mixture that contained equal volumes of ropivacaine 7.5 mg/mL and mepivacaine 20 mg/mL with epinephrine 5 mug/mL, in a total amount that corresponded to 0.5 mL/kg (minimum 30 mL, maximum 50 mL). Block effectiveness (analgesia or anesthesia of all 5 nerves below the elbow after 30 minutes), performance and onset times, needle insertion depth and dorsal angle, twitch type, analgesia of the individual nerves, and incidence of adverse events and complications, as well as patient's acceptance, were recorded.

RESULTS

One hundred forty-three patients (91%) had successful blocks, 12 patients required supplementary nerve blocks in the axilla, 3 patients had total failures of blocks (no forearm analgesia at all), and 2 patients were excluded from the assessments. Median block performance time was 4 minutes (range, 2-10 minutes) and the onset time 20 minutes (range, 10-50 minutes). Plexus nerves were found at a mean depth of 53 mm +/- 10 mm and the needle dorsal angle was 23 degrees +/- 9 degrees . Four patients experienced painful paresthesias and 3 patients had accidental punctures of axillary vessels. Signs or symptoms of complications (hematoma, local anesthetic toxicity, pneumothorax, or neuropraxias) were not observed. Only 3 patients would prefer general anesthesia in the future. Finger/wrist extension may be an optimal twitch response (P = .14).

CONCLUSIONS

Block effectiveness (91%) and onset time (20 minutes) were satisfactory and comparable to the vertical paracoracoid approach. The low rate of axillary vessel punctures (2%) may be the most important advantage of this block. The needle insertion depth measurements confirmed the MRI findings, but the dorsal angle was steeper than predicted.

Localization and pharmacological characterization of voltage dependent calcium channels in cultured neocortical neurons

The physiological significance and subcellular distribution of voltage dependent calcium channels was defined using calcium channel blockers to inhibit potassium induced rises in cytosolic calcium concentration in cultured mouse neocortical neurons. The cytosolic calcium concentration was measured using the fluorescent calcium chelator fura-2. The types of calcium channels present at the synaptic terminal were determined by the inhibitory action of calcium channel blockers on potassium-induced [3H]GABA release in the same cell preparation. L-, N-, P-, Q- and R-/T-type voltage dependent calcium channels were differentially distributed in somata, neurites and nerve terminals. omega-conotoxin MVIIC (omega-CgTx MVIIC) inhibited approximately 40% of the Ca(2+)-rise in both somata and neurites and 60% of the potassium induced [3H]GABA release, indicating that the Q-type channel is the quantitatively most important voltage dependent calcium channel in all parts of the neuron. After treatment with thapsigargin the increase in cytosolic calcium was halved, indicating that calcium release from thapsigargin sensitive intracellular calcium stores is an important component of the potassium induced rise in cytosolic calcium concentration. The results of this investigation demonstrate that pharmacologically distinct types of voltage dependent calcium channels are differentially localized in cell bodies, neurites and nerve terminals of mouse cortical neurons but that the Q-type calcium channel appears to predominate in all compartments.

Effects of gamma-aminobutyric acid (GABA) on synaptogenesis and synaptic function

The correct establishment and function of synapses depend on a variety of factors, such as guidance of pre- and postsynaptic neurons as well as receptor development and localization. gamma-Aminobutyric acid (GABA) has a pronounced effect on these events and elicits differentiation of neurons; that is, GABA acts as a trophic signal. Accordingly, activating preexisting GABA receptors, a trophic GABA signal enhances the growth rate of neuronal processes, facilitates synapse formation, and promotes synthesis of specific proteins. Transcription and de novo synthesis are initiated by the GABA signal, but the intracellular link between GABA receptor activation and DNA transcription is largely unknown. GABA also controls the induction and development of functionally and pharmacologically different GABAA receptor subtypes. The induced receptors are likely to be inserted only into the synaptic membrane domain. However, this ability to target the induced GABAA receptors is probably coupled to the maturation of neurons and not to the action of GABA per se. The induced GABAA receptors apparently mediate a pronounced inhibition of neurotransmitter release, whereas other subtypes of GABAA receptors may be modulatory rather than inhibitory.

Spectral components of cytosolic [Ca2+] spiking in neurons

We show here, by means of evolutionary spectral analysis and synthesis of cytosolic Ca2+ ([Ca2+]c) spiking observed at the single cell level using digital imaging fluorescence microscopy of fura-2-loaded mouse cerebellar granule cells in culture, that [Ca2+]c spiking can be resolved into evolutionary spectra of a characteristic set of frequencies. Non-delayed small spikes on top of sustained [Ca2+]c were synthesized by a main component frequency, 0.132+/-0.012 Hz, showing its maximal amplitude in phase with the start of depolarization (25 mM KCI) combined with caffeine (10 mM) application. Delayed complex responses of large [Ca2+]c spiking observed in cells from a different set of cultures were synthesized by a set of frequencies within the range 0.018-0.117 Hz. Differential frequency patterns are suggested as characteristics of the [Ca2+]c spiking responses of neurons under different conditions.

Expression of the GABA(A) receptor alpha6 subunit in cultured cerebellar granule cells is developmentally regulated by activation of GABA(A) receptors

Primary cultures of cerebellar granule cells, prepared from cerebella of 7-day-old rats and cultured for 4 or 8 days, were used to study the neurodifferentiative effect of a GABA(A) receptor agonist, 4,5,6,7-tetrahydroisoxazol[5,4-c]pyridin-3-ol (THIP), on the expression of the alpha6 GABA(A) receptor subunit. Membranes prepared from these cultures were photolabeled with the imidazobenzodiazepine [3H]Ro15-4513. In THIP-treated cultures at 4 days in vitro (DIV), photolabeled [3H]Ro15-4513 binding in membranes was significantly increased for both the 51 kilodalton, kDa, (alpha1 subunit) and 56-kDa (alpha6 subunit) radioactive peaks in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In contrast, THIP-treated granule cells at 8 DIV demonstrated a small but significant decrease from control cultures in the photoincorporation of [3H]Ro15-4513 in the 51-kDa peak; however, no significant change in [3H]Ro15-4513 binding was observed for the 56-kDa polypeptide. Immunolabeling of the alpha6 subunit using silver-enhanced, immuno-gold staining of granule cells showed a significant effect with THIP treatment only at 4 DIV and not at 8 DIV. Examination by light microscopy demonstrated that the major effect of THIP was to increase alpha6 subunit clustering on granule cell bodies as well as neurites, 15-fold and sixfold, respectively. Using in situ hybridization, a small THIP-induced increase in alpha6 mRNA was detected at 4 DIV; however, no effect was apparent at 8 DIV. These data suggest that THIP has a trophic effect on alpha6 subunit expression, and this effect occurs only at an early developmental stage. Moreover, this study presents further evidence for the role of GABA(A) agonists, and thus the neurotransmitter, GABA, in regulating the expression of GABA(A) receptor subunits in the developing cerebellum.

Water transport by the Na+/glucose cotransporter under isotonic conditions

Solute cotransport in the Na+/glucose cotransporter is directly coupled to significant water fluxes. The water fluxes are energized by the downhill fluxes of the other substrates by a mechanism within the protein itself. In the present paper we investigate the Na+/glucose cotransporter expressed in Xenopus oocytes. We present a method which allows short-term exposures to sugar under voltage clamp conditions. We demonstrate that water is cotransported with the solutes despite no osmotic differences between the external and intracellular solutions. There is a fixed ratio of 195:1 between the number of water molecules and the number of Na+ ions transported, equivalent to 390 water molecules per glucose molecule. Unstirred layer effects are ruled out on the basis of experiments on native oocytes incubated with the ionophores gramicidin D or nystatin.