超高效液相色谱-串联质谱测定尿中14种β-内酰胺类抗生素残留

目的 建立测定尿液中14种β-内酰胺类抗生素残留的超高效液相色谱-串联质谱分析方法。 方法 尿液经酶解后,Oasis PRiME HLB(200 mg,6 ml)固相萃取柱净化,采用Waters BEH C18色谱柱(2.1 mm×100 mm, 1.7 μm),0.01 mol/L乙酸铵的水-甲醇作为流动相进行梯度洗脱,电喷雾离子源电离,正离子扫描,多反应监测模式进行定性和定量分析。 结果 阿莫西林和头孢曲松的线性范围为10～1 000 ng/ml,其余12种β-内酰胺类抗生素为5～1 000 ng/ml,相关系数均大于0.99。阿莫西林和头孢曲松的定量限为10 ng/ml,其余的方法定量下限为5 ng/ml,检出限为0.5～2.9 ng/ml,3个加标水平下的回收率为79.8%～97.9%,相对标准偏差为2.1%～11.9%。 结论 该方法操作简便、具有较高的灵敏度、特异度和精确性,适用于尿中痕量14种β-内酰胺类抗生素残留量的测定。     

Bronchorelaxation of the human bronchi by CFTR activators

The airway functions are profoundly affected in many diseases including asthma, COPD and cystic fibrosis (CF). CF the most common lethal autosomal recessive genetic disease is caused by mutations of the CFTR (Cystic Fibrosis transmembrane Conductance Regulator) gene, which normally encodes a multifunctional and integral membrane cAMP regulated and ATP gated Cl⁻ channel expressed in airway epithelial cells.Using human lung tissues obtained from patients undergoing surgery for lung cancer, we demonstrated that CFTR participates in bronchorelaxation. Using human bronchial smooth muscle cells (HBSMC), we applied iodide influx assay to analyze the CFTR-dependent ionic transport and immunofluorescence technique to localize CFTR proteins. Moreover, the relaxation was studied in isolated human bronchial segments after pre-contraction with carbachol to determine the implication of CFTR in bronchodilation.We found in HBSMC that the pharmacology and regulation of CFTR is similar to that of its epithelial counterpart both for activation (using forskolin/genistein or a benzo[c]quinolizinium derivative) and for inhibition (CFTR_inh-172 and GPinh5a). With human bronchial rings, we observed that whatever the compound used including salbutamol, the activation of muscular CFTR leads to a bronchodilation after constriction with carbachol.Altogether, these observations revealed that CFTR in the human airways is expressed in bronchial smooth muscle cells and can be pharmacologically manipulated leading to the hypothesis that this ionic channel could contribute to bronchodilation in human.     

Isolated orbital mucoceles in the absence of obstructive sinus disease

Orbital surgeons are quite familiar with the diagnosis and management of paranasal sinus mucoceles due their frequent involvement of the orbit. These benign masses form and expand following sinus outflow obstruction secondary to various causes including trauma, inflammation and malignancy, amongst others. The authors present two cases of isolated orbital mucoceles without associated sinus outflow obstruction. There were notably no connections between the paranasal sinuses and the lesions. The mucoceles were diagnosed following orbitotomies and excisional biopsies with confirmatory histopathology. These rare orbital lesions should be considered when evaluating cystic orbital lesions, and the orbital surgeon should be familiar with the proposed pathophysiology and treatment recommendations.     

Retroperitoneal Spinal Extradural Arachnoid Cyst Combined with Congenital Hemivertebrae

Spinal extradural arachnoid cysts usually cause symptoms related to spinal cord or nerve root compression. Here, we report an atypical presentation of a spinal extradural arachnoid cyst combined with congenital hemivertebra which was presented as a retroperitoneal mass that exerted mass effects to the abdominal organs. On image studies, the communication between the cystic pedicle and the spinal arachnoid space was indistinct. Based on our experience and the literature of the pathogenesis, we planned anterior approach for removal of the arachnoid cyst in order to focus on mass removal rather than ligation of the fistulous channel. In our estimation this was feasible considering radiologic findings and also essential for the symptom relief. The cyst was totally removed with the clogged ''thecal sac-side'' end of the cystic pedicle. The patient was free of abdominal discomfort by one month after the surgery.     

Evaluation of masticatory activity during unilateral single tooth clenching using muscle functional magnetic resonance imaging

Masticatory muscle activity during teeth clenching is affected by occlusal pattern. However, few studies have performed simultaneous evaluation of all masticatory activities during teeth clenching under various occlusal conditions. The aim of this study was to use muscle functional magnetic resonance imaging (mfMRI) to evaluate the effects of changes in occlusal point on masticatory activity during single tooth clenching. Changes in mean proton transverse relaxation time (?T2) as an index of activity in all masticatory muscles during left unilateral clenching at the first molar or first premolar for 1 min were examined in nine healthy volunteers. Bite force was maintained at 40% of the maximum voluntary clenching force. The ?T2 values of the masseter and lateral pterygoid muscles were analysed separately for superficial and deep layers, and for superior and inferior heads. The ?T2 values for the ipsilateral deep masseter were significantly lower, and for the superior head of the ipsilateral lateral pterygoid muscles were significantly higher, after left first premolar clenching compared to left first molar clenching. These results quantitatively demonstrate a significant increase in activity of the superior head of the ipsilateral lateral pterygoid muscle and a significant decrease in activity of the ipsilateral deep masseter muscle with forward displacement of the occlusal contact point during unilateral tooth clenching.