AIM:To develop a microbiological method for determining plasma doxycyclineMETHODS:Plasma concentration of doxycycline was detected with Staphylococcus aureus ATCC 26003 and Micrococcus luteus ATCC 28001 strains in a variety of culture media and pHsRESULTS:Linear scope of doxycycline(016～100mg/L,r=09 985) could be achieved with using a microbiological method,which consisted of staphylococcus aureus and bovine heart soup culture medium at pH 50CONCLU_SION:This method can be used in study of pharmacokinetics and bioavailability of doxycycline

OBJECTIVE:To study the pharmacokinetics and bioequivalence of both domestic ranitidine hydrochloride capsules and imported ranitidine hydrochloride tablets.METHODS:20healthy volunteers were randomized into groups,whose plasma concentrations of ranitidine were determined at different time after single oral dose of300mg ranitidine hydrochloride capsule or ranitidine hydrochloride tablets300mg by own control by a RP-HPLC method,the pharmacokinetic parameters were computed and which were experienced variance analysis and two-way t-tests and one-way t-tests.RESULTS:The respective pharmacokinetic parameters of ranitidine hydrochloride tablets and ranitidine hydrochloride capsuless were as fol?lows,the C max were(1247.1?547.5)?g/L and(1294.8?613.2)?g/L;t max were(2.98?0.73)h and(2.73?0.80)h;t 1/2 were(3.17?0.36)h and(3.33?0.42)h;AUC 0～t were(5805.9?1403.5)(?g?h)/L and(5941.2?1526.3)(?g?h)/L;AUC 0～∞ were(6163.8?1456.4)(?g?h)/L and(6351.8?1652.7)(?g?h)/L;The relative bioavailability of the ranitidine hydrochloride capsules to ranitidine hydrochloride tablets was(104.3?24.3)%.CONCLUSION:Ranitidine hydrochloride capsules and the ranitidine hydrochloride tablets were bioequivalent.

Objective:To explore the feasibility, safety and clinical efficacy of using the self-developed acetabular posterior wall and column integrative anatomical plate to treat various types of posterior wall/column fractures.Methods:Between January 2016 and January 2019, 21 patients involving acetabular posterior wall and/or column were treated with the novel acetabular posterior wall and column integrative plate, the data were collected and retrospectively analyzed. There were 11 males and 10 females, with an average of 48 years old (range, 18-65 years old). According to the classification of AO/OTA, there were 6 simple fractures, 9 comminuted fractures, and 6 associated with joint surface compression of posterior wall; and there were 16 simple acetabular posterior wall fractures and 5 cases associated with acetabular posterior column fractures. Before operation, the CT data of each patient was collected and imported into Mimics software to reconstruct and print a 3D model of pelvis and injured and mirrored side to simulate operation. All patients were treated with a single Kocher-Langenbeck approach for posterior acetabular fractures, and fixed with the novel integrated anatomical plate after satisfactory reduction was achieved. Matta score was used to evaluate the quality of fracture reduction, and the modified Merle D'Aubigné-Postel score was adopted to evaluate functional recovery of hip joint.Results:21 patients involved in this study, the average time of plate insertion after successful reduction was 20 min (range, 15-30 min); the mean time of operation was 180 min (range, 90-300 min); the intraoperative mean bleeding volume was 700 ml (range, 300-1 500 ml). All the incisions healed by level 1 classification, and no incisions infection and sciatic nerve injury occurred. The patients included in the study have been followed up for at least one year and the imaging data was intact, the mean follow-up time was 19 month (range, 12-26 month). The fracture reduction was evaluated according to the Matta score: 16 cases were anatomical reduction, 3 cases were satisfactory reduction, 2 cases were unsatisfactory reduction, the satisfactory rate of reduction was 90.5% (19/21); the modified Merle D'Aubigné-Postel score at 3 month was 13.0±2.2 (range, 9-16), 6 month was 15.8±2.4 (range, 10-18) and last follow up was 17.0±1.8 (range, 13-18), respectively; the difference was statistically significant ( F=15.38, P < 0.001). At the last follow-up, 15 cases were excellent, 3 cases were good and 3 cases were fair, the total excellent and good rate was 85.7% (18/21). One case developed symptoms of sciatic nerve injury after operation, but the symptoms resolved after treating with neurotrophic drug by 6 months. 2 cases developed arthritis related pain after operation, receiving symptomatic treatment with oral painkillers. During the follow-up period, no complications such as plate broken and screw loosen occurred. Conclusion:The use of an integrative anatomical plate for treating posterior wall/column fractures of acetabulum achieved satisfactory fixation and postoperative functional recovery.

Objective:To summarize the clinical characteristics and prognosis of acute hyperextension spinal cord injury (SCI) in children, and to provide some recommendations for the treatment and prevention of this disease.Methods:Reviewed the data of children of SCI after sustained or repeated hyperextension of the spine at Wuhan Union Hospital and Wuhan Children's Hospital from September 2010 to September 2020. According to the American Spinal Injury Association impairment scale (AIS grade), the patients were divided into complete SCI group and incomplete SCI group. The age, symptoms and evolution after injury, neurological level of injury, imaging data, laboratory examination data, prognosis and complications of the two groups were analyzed. Retrospectively summarize the characteristics of this type of injury.Results:Forty-four cases of acute hyperextension SCI in children were included. Their age ranged from 3 to 10 years old, 95% of them were under 8 years old and 95% of them were female. There was no significant difference in age at injury and time of dance training between children with complete SCI and incomplete SCI. Back and leg pain, lower limb weakness or paresthesia, and rapidly progress to complete or incomplete SCI in a short period were typical symptoms. All blood test results anddiagnostic analysis of cerebrospinal fluid were unremarkable or negative. There was no fracture or dislocation in the whole spine. Magnetic resonance imaging showed a longitudinally extended intramedullary high-intensity signal in the thoracolumbar spinal cord. Complete SCI accounted for 60% of all cases, and the prognosis was poor with spinal cord atrophy and various complications.Conclusion:Children younger than 10 years old after sustained or repeated hyperextension of the spine may suffer acute hyperextension SCI. Children with complete SCI have poor prognosis and serious complications. Therefore, prevention of this type of injury is the best strategy.