Objective To study the imaging characteristics of intracranial dysembryoplastic neuroepithelial tumors(DNT),and to evaluate the role of CT and MRI in their diagnosis.Methods We presented 8 DNTs cases confirmed histopathologically after operation.CT and MRI features were retrospectively analyzed(3 cases received MR scan only and 5 had both studies),compared with the surgical findings and pathological appearance.Results Eight patients had totally 11 tumors with multifoci in 2 cases.Six DNTs were located in the temporal lobe,1 lesion involved the parietal lobe,1 in the frontal lobe,1 in the brain stem,1 in the cerebellum,and 1 in the frontal and temporal lobe simultaneously.All lesions were observed intracortically,and partial of them extended into the subcortical location.On 5 non-contrast CT scans,3 DNTs were homogeneously hypodense;1 case contained isodense nodules within the hypodense focus.Peripheral spotty calcification was found in 1 case.On pre-contrast MR images,all lesions showed hypointense on T_1-weighted images,moreover,multicystic change with more markedly decreased signal intensity was observed.The DNT had a well-demarcated,multinodular gyriform configuration,or a soap bubble appearance at the cortical margin.On T_2-weighted images,high signal intensity of the tumors was seen except for hypointense calcification.The bone remodeling of the adjacent calvaria was noticed in(1 case.) The tumors had slightly increased signal intensity on FLAIR(fluid attenuated inversion recovery) in 2 cases,and homogeneously mild hyperintense on PDW(proton density weighted imaging),while the isointense focus was observed in one case on DWI(diffusion weighted imaging).No obvious enhancement was identified except 1 lesion with mild enhancement following intravenous administration of contrast material.3 tumors had ill-defined contours,whereas the others showed well-demarcated margins.No surrounding vasogenic edema was present except 2 foci with slight edema.Conclusion DNT usually shows characteristic radiologic findings,in combination with the clinical presentation and history,the diagnostic accuracy should be improved,and,as such,unnecessary radiation and/or chemotherapy may be avoided.

Objective To determine the expression of cathepsin L2 (CTSL2)and evaluate its activity in skin lesions of seborrheic keratosis (SK),to observe the ultrastructural changes of melanosomes in the skin lesions of SK,and to estimate the effect of CTSL2 on the degradation of melanosomes.Methods Twenty patients with SK were enrolled from the Department of Dermatology,Renmin Hospital of Wuhan University.The lesional tissue and the perilesional normal skin were biopsied from each patient.Among 15 of the 20 patients,hematoxylin and eosin (HE)staining and Fontana-Masson silver staining were performed to observe the distribution of melanin granules,transmission electron microscopy (TEM)was conducted to observe the ultrastructural changes of melanosomes,and immunohistochemical staining was performed to estimate the cellular proliferative activity.RT-PCR and fluorogenic substrate cleavage assay were performed in the other 5 patients to determine the mRNA expression of CTSL2 and evaluate its activity,respectively.Sucrose density gradient ultracentrifugation was performed to isolate and purify melanosomes from the retinal pigment epithelium (RPE) harvested from a discarded eyeball of a 35-year old male patient with informed consent.The purified melanosomes were incubated with epidermal lysates of SK lesions,and TEM was used to observe the changes in the membrane structure of melanosomes.Statistical analysis was carried out by paired t test,and a P value ＜ 0.05 was considered statistically significant.Results A large number of melanin granules were deposited in SK lesions,while the linear deposition of melanin granules was only seen in the basal layer of the normal skin.TEM showed that the percentage of damaged melanosomes was much higher in the normal skin (49.00％ ± 4.00％) than in the SK lesions (24.33％ ± 3.06％)(t =8.49,P ＜ 0.05).RT-PCR revealed that the mRNA expression and activity of CTSL2 were both significantly lower in the SK lesions than in the normal skin (mRNA:0.35 ± 0.09 vs.0.43 ± 0.08,t =3.17,P ＜ 0.05;activity:17.46 ± 0.45 vs.28.78 ± 0.58,t =34.29,P ＜ 0.05).Moreover,TEM also showed that the percentage of damaged melanosome was lower in the SK lesion lysate-treated group (32.33％ ± 4.93％) than in the normal skin lysate-treated group (43.00％ ± 2.65％,t =3.30,P ＜ 0.05).Conclusion Decreased expression of CTSL2 in the SK lesions can affect the degradation of melanosomes by keratinocytes.However,whether CTSL2 directly takes part in the pathogenesis of SK or not is still needed to be further confirmed.

AIM:To investigate the role of phosphoenolpyruvate carboxykinase 1(PCK1)in the proliferation and migration of mouse vascular smooth muscle cells(VSMCs)and the underlying mechanism.METHODS:The prolif-eration and migration of mouse VSMCs were induced by platelet-derived growth factor(PDGF)-BB.The cells were divided into a vehicle group and a PDGF-BB group.The expression of PCK1 was detected by Western blot and immunofluores-cence staining.The mouse Pck1 siRNA(si Pck1)were transfected into mouse VSMCs to silence PCK1.The cells were di-vided into the vehicle,si Pck1+vehicle,PDGF-BB and si Pck1+PDGF-BB groups.The protein level of PCK1 was detected by Western blot.The proliferation was explored by Ki-67 immunofluorescence staining and the viability was detected by CCK-8 assay.The migration was determined by a scratch test.Mitochondrial dynamics were observed via transmission electron microscopy.A lentivirus carrying dynamin-related protein 1(Drp1)gene(lenti-Drp1)was transfected into VSMCs to induce them to overexpress DRP1.The cells were divided into the PDGF-BB,si Pck1+PDGF-BB,lenti-Drp1+PDGF-BB and lenti-Drp1+si Pck1+PDGF-BB groups.Proliferation,migration and mitochondrial dynamics were measured as described above.RESULTS:PDGF-BB increased the protein expression of PCK1 and DRP1,cell viability,the per-centage of Ki-67-positive cells,the wound healing rate and mitochondrial division in VSMCs.These effects were sup-pressed when PCK1 protein expression was silenced.After DRP1 was overexpressed,the inhibitory effects of PCK1 silenc-ing on cell viability,the percentage of Ki-67-positive cells,the wound healing rate and mitochondrial division were signifi-cantly reversed.CONCLUSION:PCK1 promotes the mitochondrial division,proliferation and migration of VSMCs in mice by upregulating the expression of DRP1.