Determination of fucoidan in rat plasma by HPLC and its application in pharmacokinetics.

This is a new expanded method of determining the characterisation of fucoidan from Laminaria japonica (kelp) in rat plasma by high-performance liquid chromatography (HPLC) with fluorescence detection. We tagged fucoidan by fluoresce in isothiocyanate (FITC) for tracking and treated the plasma samples via protein precipitation with 10% trichloroacetic acid and methanol. Column chromatography separation was on a TSK-G4000sw column (7.8 mm × 300 mm, 5 mm) by elution with 0.15 M NaCl. The quantification of fucoidan was performed by HPLC with fluorescence detection. The results suggested that the calibration curve for fucoidan concentration was linear dependent in the limits of 0.5-100µg/mL. The lower limit of quantitation (LLOQ) was 0.5µg/mL and the lower limit of detection (LLOD) was 0.15µg/mL. The intra-day and inter-day precision values were less than 13%and the accuracy ranged from 96.83 to 100.03% at 3 different concentrations. The fucoidan stability of rat plasma at different temperatures and time-points was estimated. The extraction efficiencies ranged from 93.33 to 96.53%and the matrix effect ranged from 92.67 to 95.83%. Method selectivity was evaluated as well. We successfully studied the pharmacokinetic of fucoidan in rat plasma after oral by the validated method. Fucoidan was administered to rats intravenously at a dose of 6 mg/kg and orally at a dose of 20 mg/kg. The Cmax was 7.33µg/mL within 2 h by oral administration; The initial Cmax was 75.59µg/mL. The bioavailability of fucoidan after oral administration to rats was 8.91%.

Pre-evacuation Time Estimation Based Emergency Evacuation Simulation in Urban Residential Communities.

The timely and secure evacuation of an urban residential community is crucial to residents' safety when emergency events happen. This is different to evacuation of office spaces or schools, emergency evacuation in residential communities must consider the pre-evacuation time. The importance of estimating evacuation time components has been recognized for approximately 40 years. However, pre-evacuation time is rarely discussed in previous community-scale emergency evacuation studies. This paper proposes a new method that estimates the pre-evacuation time, which makes the evacuation simulation in urban residential communities more realistic. This method integrates the residents' pre-evacuation behavior data obtained by surveys to explore the influencing factors of pre-evacuation time and builds a predictive model to forecast pre-evacuation times based on the Random Forest algorithm. A sensitivity analysis is also conducted to find the critical parameters in evacuation simulations. The results of evacuation simulations in different scenarios can be compared to identify potential evacuation problems. A case study in Luoshanqicun Community, Pudong New District, Shanghai, China, was conducted to demonstrate the feasibility of the proposed method. The simulation results showed that the pre-evacuation times have significant impacts on the simulation procedure, including the total evacuation time, the congestion time and the congestion degree. This study can help to gain a deeper understanding of residents' behaviors under emergencies and improve emergency managements of urban communities.

Buried bumper syndrome causing rectus abdominis necrosis in a man with tetraplegia.

STUDY DESIGN: Case report. OBJECTIVES: To enhance the early recognition of buried bumper syndrome in patients with tetraplegia requiring percutaneous endoscopic gastrostomy (PEG). SETTING: Inpatient unit, Massachusetts, USA. METHODS: A 44 year-old man with C2 American Spinal Injury Association grade A tetraplegia with a relatively recent PEG insertion secondary to poor nutritional intake. RESULTS: Several months after PEG placement, patient became febrile, hypotensive and complained of abdominal pain. Plain films showed a dilated bowel suggestive of ileus. Abdominal and pelvic computed tomography with and without contrast revealed PEG tube dislodgement, and a 21 cm x 2.8 cm left anterior abdominal wall collection consisting of air and contrast. Upon surgical intervention, the left rectus abdominis sheath and muscle were found to be necrotic. CONCLUSION: Buried bumper syndrome is a serious complication related to PEG tubes. For many people with tetraplegia, PEG is a life-saving procedure with minimal risks. However, emergencies do occur, making prompt recognition imperative to prevent a fatal sequela.