Roles of epidermal growth factor receptor signaling pathway in silicon dioxide-induced epithelial-mesenchymal transition in human pulmonary epithelial cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effect of silicon dioxide (SiO₂) on the expression of E-cadherin, α-smooth muscle actin (α-SMA), and transforming growth factor β₁(TGF-β₁) in human pulmonary epithelial cells (A549) with epithelial-mesenchymal transition (EMT), and to study the roles of epidermal growth factor receptor (EGFR) signaling pathway in SiO₂-induced EMT in A549 cells in vitro.</p><p><b>METHODS</b>Alveolar macrophages (AMs) were stimulated with 50 µg/ml SiO₂for 3, 6, 12, 18, 24, or 36 h, and the supernatants were collected to measure the expression of TGF-β₁protein by ELISA. The AM supernatant in which TGF-β₁reached the highest expression (T=18 h) was used as AM-conditioned supernatant. A549 cells were cultured in AM-conditioned supernatant and stimulated with indicated doses of SiO₂(0, 50, 100, and 200 µg/ml) for 48 h. The cell morphological changes were observed using an inverted microscope. The cells were collected at different times, and the mRNA and protein expression levels of E-cadherin, α-SMA, and EGFR were measured by RT-PCR and immunocytofluorescence, respectively.</p><p><b>RESULTS</b>After stimulation by SiO₂, the expression level of TGF-β₁protein at each time point was significantly higher in the presence of AM supernatants than in the absence of AM supernatants (P<0.05). With the action time, the expression level of TGF-β₁protein increased at first and then decreased, and the highest level was reached at 18 h. After exposure to SiO₂, A549 cells exhibited mesenchymal characteristics, such as a spindle shape, pseudopodia change, and fibroblast-like morphology, as observed by inverted microscope, especially in the 200 µg/ml group. With increased concentration of SiO₂, the mRNA and protein expression of E-cadherin was down-regulated gradually, especially in the 200 µg/ml group, whereas the mRNA and protein expression of α-SMA and EGFR was up-regulated gradually, especially in the 200 µg/m1 group. There were significant differences between the SiO₂-treated groups (50, 100, and 200 µg/ml SiO₂) and the control group (P<0.05).</p><p><b>CONCLUSION</b>After being stimulated by SiO₂in vitro, AMs have significantly increased expression level of TGF-β₁protein. The AM supernatant together with SiO₂can induce the transition of pulmonary epithelial cells to mesenchymal cells, and its mechanism may be related to the EGFR signaling pathway.</p>

Clinical variability of Charcot-Marie-Tooth disease type 1A patients with PMP22 duplication mutation / 中华神经科杂志

Objective To investigate the characteristics of PMP22 duplication mutation and the clinical variability of Charcot-Marie-Tooth disease type 1A (CMT1A) patients. Methods PMP22 duplication mutation analysis were performed in 45 cases diagnosed probably CMT by combination of improved allele-specific PCR-restriction enzyme digestion and short tandem repeat (STR) analysis based on laser-induced fluorescence detection in capillary electrophoresis. The clinical features of the positive cases were precisely analyzed. Results With the combined use of two methods, PMP22 duplication was detected in 21 cases, i.e. 10 CMT1 cases with typical presentations including weakness and atrophy in the distal limbs, and 11 atypical cases with special phenotypes including 1 case with mild dizziness, 1 case with hearing loss, 2 cases with recurrent limbs weakness, 2 cases with postural tremor in the upper limbs, 4 cases with cerebellar ataxia and 1 case with epilepsy. Conclusions The improved allele-specific PCR-restriction enzyme digestion provides the accurate, reliable and feasible method to detect PMP22 duplication, which is the most common cause of CMT. Comprehensive analysis of clinical, electrophysiological and pathological features of the CMT1A patients with positive PMP22 duplication indicate the high clinical variability of this disease.

Diagnosis and treatment of functional delayed gastric emptying after subtotal gastrectomy:a report of 53 cases / 中国普通外科杂志

ObjectiveTo determine the possible causes for functional delayed gastric emptying (FDGE) and its diagnosis and treatment. MethodsThe clinical data of 53 FDGE patients after subtotal gastrectomy from 1987 to 2001 were retrospectively analysed. ResultsAll the 53 patients were recovered and discharged. Among them, 11 were misdiagnosised as mechanical ileus and were reoperated on. ConclusionsThe main cause of FDGE may be the disturbance of gastrointestinal motility which may be caused by vegetative nerve injury during the operation. The main therapy is non-surgical treatment and reoperation should be avoided at the early stage.

nsory axonal neuropathy: a clinical and electrophysiological study / 中华神经科杂志

jective To study the clinical and electrophysiological characteristics of sensory axonal neuropathy (SAN). Methods Clinical data in 24 patients with SAN and 88 age-matched normal controls were examined. Sensory and motor nerve conduction were evaluated with supramaximal stimulation and surface electrodes in 180 nerves at different nerve segments of normal subjects, and compared with that of 90 nerves with sensory axonal neuropathy. Results Sensory symptoms of numbness and sensory ataxia were seen in 91. 6% of the patients, 70. 8% of them were mainly involved in the lower extremities. No weakness and fasciculation were found in our patients. Nerve conduction studies showed a normal MCV and CMAP amplitude, but the decreased amplitude of SNAP and slowed SCV in our patients had significant differences as compared with that of the normal subjects (P