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Objective To investigate whether there is endogenous neural stem cell proliferation and whether these proliferated neural stem cells represent neural plasticity in the adult rats after cerebral infarction. Methods Cerebral infarction models of rats were established and the dynamic expression of bromodeoxyuridine (BrdU), BrdU/polysialylated neural cell adhesion molecule (PSA-NCAM) were determined by immunohistochemistry and immunofluorescence staining. BrdU was used to mark dividing neural stem cells. PSA-NCAM was used to mark the plasticity of neural stem cells. Results Compared with controls, the number of BrdU-positive cells in the subventricular zone (SVZ) and hippocampus increased significantly at 1st day after cerebral infarction (P < 0. 05 ), reached maximum at 7th day, decreased markedly at 14th day, but it was still elevated compared with that of the controls (P < 0.05). The number of BrdU-labeled with PSA-NCAM-positive cells increased significantly at 7th day (P < 0.05 ), reached maximum at 14th day, markedly decreased at 28th day, but it was still elevated compared with that of the controls (P < 0.05). It was equal to 60% of the number of BrdU-positive cells in the same period. Conclusion Cerebral infarction may stimulate the proliferation of endogenous neural stem cells in situ and most proliferated neural stem cells represent neural plasticity. [ABSTRACT FROM AUTHOR]

Objective To evaluate the expression of telomerase transcriptional elements-interacting factor (TEIF) in human testis under different status and its relation with human telomerase reverse transcriptase (hTERT) expression. Methods Specific antisera against TEIF were generated by immunization of rabbits with purified recombinated partial TEIF. Samples were assigned to three groups according to their pathological types, including 16 normal testes, 8 atrophic testes, and 6 testicular seminomas. They were subjected to immunohistochemical staining of TEIF and hTERT. Results from both TEIF and hTERT were analyzed semi-quantitatively and compared. Results The expressions of TEIF and hTERT were detected in all samples of normal, atrophic testes, and seminomas. No differences of TEIF expressions among these three groups were observed (P> 0.05). On the contrary, the expressions of hTERT were significantly lower in atrophic testes compared with those of normal testes and seminomas (both P < 0.05). Nevertheless, co-expressions of TEIF with hTERT were revealed to be in normal and malignant cases (P < 0.05) but not in atrophic testes, which generally presented TEIF expression. The cellular distributions of both proteins were similar and mainly in spermatocytes and some Sertoli cells, while were all negative in the interstitial cells and other stromal cells. Conclusions The uniform expressions of TEIF in all these specimens suggest that it may be a marker of testis and its related diseases. The strong expression of hTERT in normal testes and testicular seminomas comparing with the low expression in atrophic testes may suggest a role for telomerase in maintaining proliferation of germ cells. [ABSTRACT FROM AUTHOR]

Objective To investigate the H2O2-induced expression of human histone acetyltransferase-like protein (hALP), a telomerase regulation-associated gene, and its effects on the stress-triggered cellular senescence. Methods The induced expression of hALP was measured by semi-quantitative RT-PCR and immunofluorescent histochemistry after treatment of HeLa cells by H2O2. The effects of hALP expression on cellular responses to H2O2 were analyzed by MTT, flow cytometry, and SA-β-gal staining, respectively. Results hALP mRNA could be dose-dependently induced by treatments of 0. 2–1.6 mmol/L H2O2, and the induction could be observed after 6 hours and kept for 36 hours in the presence of 0.4 mmol/L H2O2. Meanwhile, the immunofluorescent staining showed marked stronger nuclear intensity of hALP protein in H2O2-treated HeLa cells. In the treatment of H2O2, the ectopic expression of hALP enhanced continuous growth and overcame G2/M arrest as well as decreased senescence-associated β-gal staining. On the contrary, the transfected clones with antisense or blank vector and original HeLa cells presented growth suppression, G2/M delay and higher percentage of SA-β-gal activities in the presence of H2O2. Conclusions The expression of hALP could be up-regulated by treatment of H2O2, and elevated expression could enhance cellular resistance to H2Oz-induced cellular senescence. The data might be of references to elucidation of basic biological function of hALP gene and its associated telomerase activity. [ABSTRACT FROM AUTHOR]