BACKGROUND: P16 inactivation is frequently accompanied by telomerase reverse transcriptase ( TERT ) amplification in human cancer genomes. P16 inactivation by DNA methylation often occurs automatically during immortalization of normal cells by TERT . However, direct evidence remains to be obtained to support the causal effect of epigenetic changes, such as P16 methylation, on cancer development. This study aimed to provide experimental evidence that P16 methylation directly drives cancer development. METHODS: A zinc finger protein-based P16 -specific DNA methyltransferase (P16-Dnmt) vector containing a "Tet-On" switch was used to induce extensive methylation of P16 CpG islands in normal human fibroblast CCD-18Co cells. Battery assays were used to evaluate cell immortalization and transformation throughout their lifespan. Cell subcloning and DNA barcoding were used to track the diversity of cell evolution. RESULTS: Leaking P16-Dnmt expression (without doxycycline-induction) could specifically inactivate P16 expression by DNA methylation. P16 methylation only promoted proliferation and prolonged lifespan but did not induce immortalization of CCD-18Co cells. Notably, cell immortalization, loss of contact inhibition, and anchorage-independent growth were always prevalent in P16-Dnmt&TERT cells, indicating cell transformation. In contrast, almost all TERT cells died in the replicative crisis. Only a few TERT cells recovered from the crisis, in which spontaneous P16 inactivation by DNA methylation occurred. Furthermore, the subclone formation capacity of P16-Dnmt&TERT cells was two-fold that of TERT cells. DNA barcoding analysis showed that the diversity of the P16-Dnmt&TERT cell population was much greater than that of the TERT cell population. CONCLUSION P16 methylation drives TERT -mediated immortalization and transformation of normal human cells that may contribute to cancer development.
Humans ; Telomerase/genetics* ; DNA Methylation/physiology* ; Fibroblasts/cytology* ; Cyclin-Dependent Kinase Inhibitor p16/metabolism* ; Cell Line ; Cell Transformation, Neoplastic/genetics*

Objective:To clarify the application value of direct cortical electrical stimulation (DES) in locating vestibular functional cortices and the distribution of vestibular functional cortices.Methods:Implantation of stereo-electroencephalography (SEEG) electrodes was performed in 17 drug-resistant epilepsy patients in our hospital from January 2016 to December 2019. The clinical data of these patients were retrospectively analyzed. DES was performed on these patients and stimulation sites eliciting vestibular symptoms were selected to evaluate accurately anatomic locations of stimulation sites eliciting vestibular symptoms in standard Montreal Neurological Institute (MNI) space, and acquired accurate vestibular functional maps in groups.Results:There were 33 stimulation sites eliciting vestibular symptoms, including 9 sites (28%) located in the supramarginal gyrus, 6 sites (18%) located in the precuneus, 6 sites (18%) located in the posterior insular cortex, 1 site (3%) located in the anterior insular cortex, 4 sites (12%) located in the superior temporal gyrus, 2 sites (6%) located in the middle temporal gyrus, 4 sites (12%) located in the precentral gyrus, and 1 site located in cingulate cortex (3%). Stimulation sites eliciting vestibular symptoms induced by lowest intensity located in the insular cortex (average intensity was 2.43 mA), and the average intensity of 6 stimulation sites located in the posterior insular cortex was 2.17 mA.Conclusion:The functional cortex associated with vestibular symptoms defined by DES sites including the insular cortex, superior temporal gyrus, middle temporal gyrus, superior marginal gyrus, precuneus, precentral gyrus, and cingulate cortex.

Objective:To explore the relation of new-type drug using intention,self-efficacy,and perceived stress in secondary vocational school students.Methods:A total of 2692 secondary vocational school students in Zhaoqing,Guangdong Province were selected.The questionnaire of new-type drugs using intention,General Self-Efficacy Scale (GSES),and Perceived Stress Scale (PSS) were respectively used to assess the secondary vocational school students'new-type drugs using intention,self-efficacy,and perceived stress.Path analysis model was used to analyze the relationship of new-type drugs using intention,self-efficacy,and perceived stress among secondary vocational school students.Results:There were 13.6％ (295/2165) of the secondary vocational school students reported an intention to use new-type drugs.The total scores of GSES and PSS were (2.4 ±0.5) and (18.8 ±5.0),respectively.The results of path analysis showed that,after controlling for age,gender,and residence,the scores of GSES were negatively correlated with the scores of PSS (γ =-0.21,P ＜0.001),and the scores of PSS were positively correlated with the scores of questionnaire of new-type drugs using intention (γ =0.05,P ＜ 0.05).However,the scores of GSES showed no significant direct correlation with the scores of questionnaire of new-type drugs using intention (γ =0.04,P ＞ 0.05).Conclusion:The secondary vocational school students' level of perceived stress are positively correlated with their intention to use new-type drugs.Self-efficacy might moderate the individual's level of perceived stress,thus to show indirect correlation to the secondary vocational school students' intention.

OBJECTIVE:To establish a method for the contents determination of phospholipid and γ-linolenic acid in Com-pound linolenic acid soft capsule. METHODS:HPLC was conducted to determine the content of soybean lecithin;the column was Agilent TC-C18 with mobile phase of methanol-water(84:16,V/V)at a flow rate of 1.0 ml/min,the detection wavelength was 219 nm,the column temperature was 30 ℃,and the injection volume was 10 μl.Gas chromatography was conducted to determine the content of γ-linolenic acid in the preparation;the column was DB WAX,injector temperature was 210 ℃ by temperature pro-grammed,carrier gas was helium at a flow rate of 1 ml/min by split injection(split ratio of 1:30),and the injection volume was 0.02μl. RESULTS:The linear range was 4.64-16.24μg/ml for phospholipid(r=0.999 6)and 0.093 44-0.327 04μg/ml forγ-linole-nic acid methy ester(r=0.999 6);RSDs of precision,stability and reproducibility tests were lower than 3%;recoveries were 97.44%-99.36%(RSD=0.93%,n=6) and 97.22%-99.07%(RSD=1.01%,n=6),respectively. CONCLUSIONS:The method is simple,stable with good separation,and can be use for the contents determination of phospholipid and γ-linolenic acid in Com-pound linolenic acid soft capsule.

Objective To study the clinical and imaging characteristics of Chinese atopic myelitis (AM) patients.Methods Three diagnosed AM patients were retrospectively analyzed for the clinical data,serum IgE level,antigen specific IgE,cerebrospinal fluid,spinal MRI and therapeutic efficacy profiles.Results All the three patients were male and presented as subacute AM with the onset at 25,47 and 49 years old respectively.Two patients were allergic to pollen and other drugs,while another patient suffered from allergic rhinitis.Elevated serum total IgE and mite antigen specific IgE were found in all cases.Paraesthesia in limb extremities and positive Lhermitte sign were the main clinical features,while no optic,motor,urinary and defecation disturbance were found.Oligoclonal banding of cerebrospinal fluid and serum aquaporin 4 (AQP4) antibody were both negative in all cases.Spinal MRI showed lesions were hypointense on T1 and hyperintense on T2 at the posterior column of T2-3 segment with abnormal enhancement in case 1,hypointense on T1 and hyperintense on T2 at C2/3 segment with mild swelling in case 2 and hypointense on T1 and hyperintense on T2 at C3-5 segments with swelling and abnormal enhancement in case 3.Vitamin B were used in one patient,while the other two patients improved after the treatment with high-dose corticosteroids.Conclusions Subacute myelitis predominantly presents as paraesthesia in limb extremities with elevated serum total IgE and mite antigen specific IgE,while severe motor disorders are rare.Swelling and abnormal enhancement lesions at the posterior column of cervical cord are the common imaging features.Treatment with corticosteroids is recommended to be sustained for 3-6 months.

Aim To study the screening of the nucleo-tide sequences might be affected by α-syn in vitro. Methods The nucleotide sequences were synthesized according to the feature of base composition, and then mixed with the α-syn-GFP. The CD was used to ana-lyse the changes of the peak. Result The peak of the CD changed greatly when the α-syn-GFP mixed with the GC-box like sequence. Conclusion The α-syn-GFP might affect the GC-box like sequence after trans-located into the nuclei. Then, it plays a role in physio-logical and pathological conditions by affecting the reg-ulation of gene expression.

Objective To evaluate the utility of short tau inversion recovery (STIR) sequence in the diagnosis of hippocampal sclerosis ( HS).Methods Twenty-one patients with medial temporal lobe epilepsy without neoplasm lesions or injuries by conventional MRI sequence including T1WI,T2WI and FLAIR were included in this study.STIR imaging in axial,coronal and sagittal sequences was performed on these patients. Diagnosis of HS was based on the findings of hippocampal atrophy,alteration signal,disturbed internal structure and enlargement of the inferior horn. The findings shown on conventional MRI were compared with those on STIR sequence. Furthermore,the correlation of radiologic and histological findings was investigated in 6 patients operated for refractory seizures. Results On conventional MRI sequence,14 patients (66.7％) were confirmed with unilateral HS and 4 patients were suspected with unilateral HS. In contrast,all these 18 patients (85.7％) were confirmed with unilateral HS by STIR.Particularly,STIR sequence delineated the internal structure of hippocampus more clearly than conventional MRI sequences did. C shaped contour in subiculum-CA1-CA2 was revealed in normal hippocampus on STIR sequence and disappeared in HS,correlated to the pathology finding of loss of neuron in CA1 in resected tissues in 6 operated patients.The patients with HS also showed areas of hypodensity in CA4 on STIR,in accordance with pathologic findings of gliosis in this area in the 6 operated patients.Conclusion STIR sequence could depict the internal anatomical structure of hippocampus with high resolution superior to conventional MRI sequences,and can be of great value in the diagnosis of HS.

Objective In the context of worldwide shortage of amytal,explore the intracarotidpropofol test for lateralizing language area and assessing hemispheric memory function.Methods Fourteen patients with refractory partial epilepsy who were candidates for surgical intervention were included in the study.With guide under a digital subtraction angiography,propofol was injected in bilateral intracarotidsequentially.Muscle power deceasing to level 0 at the contralateral limb and eyes gazing to contralateral side were used as the mark of hemispheric anesthesia completely.The immediate language alterations were recorded.To evaluate the bilateral language and memory functions,the visual and auditory memory tasks were performed sequentially once patient could concentrate his attention ; and after limb muscle power recovering to normal level,patients were required to perform a free recall test.Any abnormal responses were recorded.Results Language dominant hemisphere was determined in 14 patients.Nine patients were confirmed as left language dominance,2 patients were right language dominance.The remained 3 patients were considered as bilateral language dominance.Meanwhile,the hemispheric memory function was able be evaluated in 13 patients.More than 67％ memory function was sustained in hemisphere contralateral to mesial temporal lesions.Transient responses including eye pain,facial muscle spasms,laughers and involuntary movements were observed.Conclusion Hemispheric language and memory functions can be assessed with direct intracarotidpropofol injection,and propofol could be an alternative drug to amobarbital used in the Wada test.

Objective To investigate the role of human membrane associated sialidase (Neu3) in multidrug resistance ( MDR) of K562 cells. Methods K562 cells and K562/ADM cells were treated with DNR alone or with combination of DNR and NeuAC2en. The cell survival rate was measured by MTT assay; the expression of MDR related factors and apoptosis related factors were determined by Western blot and RT-PCR; Neu3 activity was detected by TBA reaction. Results The survival rate of K562/ADM cells was higher than that of K562 cells; NeuAC2en showed synergistic effect with DNR(P <0. 01) ; Neu3 activity of K562 and K562/ADM cells decreased after DNR or NeuAC2en induction and the decrease was most significant in the combination treatment group (P <0. 01). Under the identical condition, the protein expression of P-gp and Neu3 and the mRNA expression of MDR1, Neu3, BCL-xl and BCL-2 increased comparing with K562 cells. The mRNA level of BAX in K562 and K562/ADM groupsdid not changed significantly. MDR1, Neu3,BCL-xl and BCL-2 decreased after DNR induction and down-regulated most obviously in the groups treated by DNR combined with NeuAC2en. Conclusion Neu3 may be related with multidrug resistance of K562/ADM cell through regulating apoptosis and the expression of MDR1.