Clinical and pathological features in children with progressive muscular dystrophy / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the clinical and pathological features of progressive muscular dystrophy (PMD) in children and to provide help for the early and accurate diagnosis of PMD.</p><p><b>METHODS</b>Retrospective analysis was performed on the clinical data of 99 hospitalized children with PMD, including clinical manifestations, age of onset, family history, creatase, electromyogram (EMG) and pathological changes of muscles.</p><p><b>RESULTS</b>Of the 99 children with PMD, the age of onset was 0.5-14.5 (4.7 ± 3.1) years. Eleven cases (11%) had a family history of PMD. Twenty-six (26%) were misdiagnosed as other diseases. All patients presented with muscle weakness when seeing the doctor, and 66 (67%) of them had muscle atrophy and/or hypertrophy. All patients had elevated creatine kinase (CK) levels. The 2-7-year-old group (n=51) had a mean CK level of 9965 ± 8876 U/L, and the 7-15-year-old group (n=48) had a mean CK level of 5110 ± 4498 U/L, with a significant difference between the two groups (P<0.01). The EMG examination performed on 66 patients showed that 54 cases (82%) had myogenic damage and 10 cases (15%) had neurogenic damage. Light microscopy revealed coexistence of atrophy and hypertrophy of muscle fibers, hyaline degeneration and granular degeneration. Electron microscopy showed that muscle fibers were different in thickness, some atrophic or hypertrophic; muscle cell nuclei moved inwardly, myofilaments dissolved and disappeared mildly under the sarcolemma, there were scattered melting lesions within muscle fibers, the numbers of glycogen granules and mitochondria increased, mild hyperplasia and expansion of sarcoplasmic reticulum were seen, and a small number of muscle fibers had necrosis.</p><p><b>CONCLUSIONS</b>Weakness of both lower extremities remains the main reason for PMD patients seeing the doctor. CK is the main laboratory indicator for diagnosis of PMD. PMD is mainly manifested as myogenic damage in the early stage and may be accompanied by neurogenic damage in the late stage, according to the EMG examination. With a high misdiagnosis rate, PMD may be misdiagnosed as many other diseases. Pathological examination under light microscope and electron microscope is the main means for confirming a PMD diagnosis.</p>

Mutations of tumor suppressor gene PTEN mutations in hepatocellular carcinoma and its implications in tumor proliferation and apoptosis / 中华病理学杂志

<p><b>OBJECTIVE</b>To study mutations of tumor suppressor gene PTEN in human hepatocellular carcinomas and its effects on the proliferation and apoptosis of hepatocellular carcinoma cell line HHCC.</p><p><b>METHODS</b>(1) PCR-SSCP and sequence analysis were used to detect the mutations of the 5th and 8th exon of PTEN in 42 cases of human primary hepatocellular carcinoma. (2) Eukaryotic expression vectors of the wild-type (pEGFP-wt-PTEN) and the mutant type (pEGFP-PTEN, G129R) of PTEN were constructed. Lipofectamine 2000 mediated gene transfection was used to transfect hepatocellular carcinoma cell line HHCC, in which the PTEN protein is not expressed. Culture medium containing G418 was used to select stable transfectants. MTT colorimetry was used to analyze the proliferation ability of selected cell lines. Naive HHCC cells and HHCC cells transfected with empty vector (pEGFP-C1) served as controls. (3) TNF-alpha was used to induce apoptosis of selected cell clones.</p><p><b>RESULTS</b>(1) Point mutation involving the 5th exon of PTEN was detected in 4 of 42 primary hepatocellular carcinomas. (2) Compared with the control groups, the proliferation of hepatocellular carcinoma cells was significantly inhibited by the transfection of wild-type PTEN gene, while the transfection with mutant PTEN construct did not significantly change the proliferation. (3) The apoptosis indices of cells transfected with the wild-type and the mutant PTEN genes were 13.8% and 8.1% respectively. Compared with the control, the apoptosis index of HHCC cell transfected by the wild type PTEN was significantly lower (P < 0.05). There were no significant differences between HHCC cells transfected with mutated PTEN gene and the control (P > 0.05). The expression of internal 473-phosphorylated Akt of HHCC was weak, but was enhanced when the cells treated with TNF-alpha. However, it was down regulated by the wild type PTEN.</p><p><b>CONCLUSIONS</b>(1) First time report that PTEN mutations can be found in 9.5% human primary hepatocellular carcinomas. (2) The expression of the wild-type PTEN can suppress the proliferation of HHCC cells, and such suppression was lost when PTEN gene was mutated. (3) PTEN inhibition of the proliferation and the enhancement of apoptosis of hepatocellular carcinoma cells is likely related to a down-regulation of the TNF-alpha induced activation of protein kinase Akt pathway.</p>