Prediction of Increased Intracranial Pressure in Traumatic Brain Injury Using Quantitative Electroencephalogram in a Porcine Experimental Model

Continuous and non-invasive measurement of intracranial pressure (ICP) in traumatic brain injury (TBI) is important to recognize increased ICP (IICP), which can reduce treatment delays. The purpose of this study was to develop an electroencephalogram (EEG)-based prediction model for IICP in a porcine TBI model. Thirty swine were anaesthetized and underwent IICP by inflating a Foley catheter in the intracranial space. Single-channel EEG data were collected every 6 min in 10 mmHg increments in the ICP from baseline to 50 mmHg. We developed EEG-based models to predict the IICP (equal or over 25 mmHg) using four algorithms: logistic regression (LR), naive Bayes (NB), support vector machine (SVM), and random forest (RF). We assessed the performance of each model based on the accuracy, sensitivity, specificity, and AUC values. The accuracy of each prediction model for IICP was 0.773 for SVM, 0.749 for NB, 0.746 for RF, and 0.706 for LR. The AUC of each model was 0.860 for SVM, 0.824 for NB, 0.802 for RF, and 0.748 for LR. We developed a machine learning prediction model for IICP using single-channel EEG signals in a swine TBI experimental model. The SVM model showed good predictive power with the highest AUC value.

Utstein recommendation for emergency stroke care

Background

Recent advances in treatment for stroke give new possibilities for optimizing outcomes. To deliver these prehospital care needs to become more efficient.

Aim

To develop a framework to support improved delivery of prehospital care. The recommendations are aimed at clinicians involved in prehospital and emergency health systems who will often not be stroke specialists but need clear guidance as to how to develop and deliver safe and effective care for acute stroke patients.

Methods

Building on the successful implementation program from the Global Resuscitation Alliance and the Resuscitation Academy, the Utstein methodology was used to define a generic chain of survival for Emergency Stroke Care by assembling international expertise in Stroke and Emergency Medical Services (EMS). Ten programs were identified for Acute Stroke Care to improve survival and outcomes, with recommendations for implementation of best practice.

Conclusions

Efficient prehospital systems for acute stroke will be improved through public awareness, optimized prehospital triage and timely diagnostics, and quick and equitable access to acute treatments. Documentation, use of metrics and transparency will help to build a culture of excellence and accountability.

Comparison of epidemiology, emergency care, and outcomes of acute ischemic stroke between young adults and elderly in Korean population: a multicenter observational study

Stroke in young adults has been known to show a lower incidence and a better prognosis. Only a few studies have examined the epidemiology and outcomes of ischemic stroke in young adults and compared them with the elderly in Korean population. All consecutive patients with ischemic stroke visiting 29 participating emergency departments were enrolled from November 2007 to October 2009. Patients with less than 15 yr of age and unknown information on age and confirmed diagnosis were excluded. We categorized the patients into young adults (15 to 45 yr) and elderly (46 yr and older) groups. Of 39,156 enrolled all stroke patients, 25,818 with ischemic stroke were included and analyzed (young adult; n=1,431, 5.5%). Young adult patients showed lower prevalence of most chronic diseases but significantly higher prevalence in exercise, current smoking, and alcohol consumption. Hospital mortality was significantly lower in young adults than elderly (1.1% vs. 3.1%, P<0.001). Higher number of patients in elderly group (68.1%) showed worsening change of modified Rankin Scale than young adults (65.2%). Young adults ischemic stroke showed favorable hospital outcomes than the elderly in Korean population.

Aminoguanidine protects against apoptosis of retinal ganglion cells in Zucker diabetic fatty rats

AIM

The inhibition of advanced glycation end products (AGEs) and the receptor for AGEs (RAGE) mediated downstream signaling pathways have been suggested to have retinoprotective actions in diabetic retinopathy. Herein, we examined the protective effects of aminoguanidine (AG), an AGEs inhibitor, on diabetes-induced injury of retinal ganglion cells in the Zucker diabetic fatty (ZDF) rats.

MATERIALS AND METHODS

Seven-week-old male ZDF rats were treated with AG (50 mg/kg body weight) once a day orally for 13 weeks. Serum and vitreous concentration of AGEs were examined. Expressions of AGEs and its receptor (RAGE) were assessed by immunohistochemistry. Southwestern histochemistry was used to detect activated nuclear factor (NF)-κB.

RESULTS

At the end of the study, vitreal levels of AGEs were significantly reduced in ZDF rats treated with AG. Similary, immunohistochemical analysis showed that AG significantly reduced the positive areas for AGEs and RAGE. Furthermore, AG strongly inhibited the loss of retinal ganglion cells by apoptosis. AG also suppressed the activation of to NF-κB.

CONCLUSIONS

Our results suggest that AG has retinoprotective properties through not only direct inhibition of AGEs formation but also downregulation of NF-κB.

The effects of antioxidants and nitric oxide modulators on hepatic ischemic-reperfusion injury in rats

Ischemic-reperfusion injury (IRI) is thought to be caused by oxygen radicals. Nitric oxide (NO) also has been thought to play a key role in IRI. This experiment was designed to evaluate the effects of antioxidants and NO supplement on hepatic IRI. Male Sprague-Dawley rats were divided into five groups: a sham operation group, a group with IRI, and three groups with vitamin C combined with vitamin E (VC&VE), L-arginine and N(G)-nitro-L-arginine (NNLA) injected after IRI. IRI was induced by clamping of the porta hepatis for 30 minutes and then by declamping. To prevent mesenteric blood congestion, a porto-systemic shunt had been made four weeks before the portal clamping. Biochemical assays of TNF-alpha level and NO2- level in the blood, malondialdehyde level, catalase activity and NO synthase activity in the liver tissue were performed. The results were as follows: IRI increased the malondialdehyde level and exhausted the catalase activity remarkably. VC&VE lowered the malondialdehyde levels and protected against catalase exhaustion, but had no significant effect on the NO production. L-arginine had a definite antioxidant effect, which was much weaker than that of VC&VE. In conclusion, antioxidants and a supplement of NO protected the liver tissue against IRI.

Determination of terbutaline enantiomers in human urine by coupled achiral-chiral high-performance liquid chromatography with fluorescence detection

A coupled achiral-chiral high-performance liquid chromatographic system with fluorescence detection at excitation/emission wavelengths of 276/306 nm has been developed for the determination of the enantiomers of terbutaline, (S)-(+)-terbutaline and (R)-(-)-terbutaline in urine. Urine samples were prepared by solid-phase extraction with Sep-pak silica, followed by HPLC. The terbutaline was preseparated from the interfering components in urine on Phenomenex silica column and the terbutaline enantiomers and betaxolol were resolved and determined on a Sumichiral OA-4900 chiral stationary phase. The two columns were connected by a switching valve equipped with silica precolumn. The precolumn was used to concentrate the terbutaline in the eluent from the achiral column before back flushing onto the chiral phase. For each enantiomer the assay was linear between 1 and 250 ng/ml (R2=0.9999) and the detection limit was 0.3 ng/ml. The intra-day variation was between 4.6 and 11.6% in relation to the measured concentration and the inter-day variation was 4.3-11.0%. It has been applied to the determination of (S)-(+)-terbutaline and (R)-(-)-terbutaline in urine from a healthy volunteer dosed with racemic terbutaline sulfate.

Determination of terbutaline enantiomers in human plasma by coupled achiral-chiral high performance liquid chromatography

Achiral-chiral column switching HPLC assay was developed to allow the separation and quantification of the enantiomers of terbutaline in human plasma by means of fluorescence detection. Plasma samples were prepared by solid-phase extraction with sep-pak silica, followed by HPLC assay. The enantiomers of terbutaline and the internal standard were separated from the biological matrix on a silica column, and the two enantiomers were resolved and quantified on a Sumichiral OA-4900 column. The two columns were connected by a switching valve equipped with silica trap column. The trap column was used to concentrate the terbutaline in the eluent from the achiral column before back flushing onto the chiral phase. For each enantiomers, the assay was linear between 2.5-125 ng/ml (r=0.9999) and detection limit was 1.0 ng/ml.

Chiral separation of the enantiomers of metoprolol and its metabolites by high performance liquid chromatography

(1'R, 2R)-, (1'R, 2S)-, (1'S, 2R)- and (1'S, 2S)-alpha-hydroxymetoprolol; (2R)- and (2S)-O-desmethylmetoprolol; and (2R)- and (2S)-metoprolol acid are major metabolites of (2R)-and (2S)-metoprolol, beta-adrenergic antagonist. The focus of most chiral separation methods until now has been on determination of the enantiomeric parent drug. However, it is just as important to be able to follow the metabolism of the enantiomers and their possible chiral metabolites. Therefore, for the study of stereoselective metabolism and pharmacokinetics of metoprolol, the chiral separation of the enantiomers of metoprolol and its metabolites has been investigated using four chiral stationary phases, i.e., Chiralcel OD, Chiral-AGP, Cyclobond I and Sumichiral OA-4900 columns. Metoprolol acid was resolved only by Sumichiral OA-4900. Chiralcel OD provided the highest separation factor and resolution value for metoprolol and O-desmethylmetoprolol and partially resolved the four stereoisomers of alpha-hydroxymetoprolol. Diastereomeric alpha-hydroxymetoprolols were resolved using the coupled column chromatographic system of two chiral stationary phases, Sumichiral OA-4900 column and Chiralcel OD column.