The inhibitory effects of actinomycin D on chromatin (or DNA) template and the stimulating effects of synthetic template Poly [d(A-T)] on transcription were observed in the liver nucleic transcriptional system of the rat in vitor.By introducing proper concentrations of actinomycin D and Poly [d(A-T)] into each reactionary system,a method to assay free RNA polymerase activity in the nucleus was established.In addition,a comparison of the contents between chromatin-engaged and free polymerase in normal rat liver nuclei isolated with hypertonic sucrose (2.3 mol/L) was made.Eventually,the possible role free RNA Polymerases play in the eukaryotic transcriptional process was discussed.

The overall cellular gene expression is well realized by the coordinated regulation between nuclear DNA and mitochondria DNA. Coordinated regulation between two genomes plays a key role not only in mitochondria biogenesis and protein synthesis but also more importantly in the regulation of gene expression of mitochondria respiratory chain subunits in order to mediate the mitochondrial respiratory function. In the present review, we focus on the mechanism of coordinated regulation between two genomes.

Classroom teaching is the focus of teaching of school and main approach to medicine course,and the quality of classroom teaching is directly related to the development of students.Thus improving classroom teaching is very important to increase integral teaching of school.This paper discusses how to increase the thinking ability of students in classroom teaching.

We have reformed the traditional pathophysiological experimental teaching from improving experimental teaching method,optimizing experimental content,updating experimental teaching material,starting design experimental and founding general examine system.

Objective To understand the effect of transforming growth factor-?_(2)(TGF-?_(2)) on the expression and activity of matrix metalloproteinase-2(MMP_(2)) in cultured bovine trabecular cells and to investigate the role of TGF-?_(2) in the pathogenesis of primary open angle glaucoma(POAG). Methods TM cells were incubated in DMEM containing 1.0?g/L TGF-?_(2) or 1.0?g/L TGF-?_(2) with 100mg/L murine monocolonal anti-human PAI-1 IgG or DMEM without any experimental reagent for 24, 36, 48h, respectively. The expression of MMP_(2) or plasminogen activator inhibitor-1(PAI-1) were assayed by Western blot. Results TGF-?_(2 )could enhance the expression of pre-form MMP_(2) and PAI-1. PAI-1 neutralizing antibody could promote transformation of the pre-form MMP_(2) to it's active form. Conclusion TGF-?_(2) can cause the accumulation of ECM in trabecular meshwork by inhibiting the activation process of pre-form MMP_(2), and thus cause the increase of aqueous humor outflow resistance, which contributes to the pathogenesis of POAG.

AIM:To observe the effect of GDP on uncoupling proteins(UCPs) activity and the efficiency of oxidative phosphorylation in hypoxic exposed rat brain mitochondria.METHODS: Adult SD rats were randomly divided into three groups (control, acute hypoxia and chronic hypoxia groups). The animals were placed into a hypobaric chamber simulated 5 000 m high altitude for 0, 3 and 30 d, respectively. The mitochondria from rat brain were isolated by centrifugation. The activity of UCPs was detected by the method of [H3]-GTP binding with UCPs specifically. The maximal binding content (Bmax) and the dissociation constant (Kd) were determined by Scatchard plot. The mitochondrial potential was measured by rhodamine 123 method. Oxidative respiratory consumption was measured by Clark electrode. The experiments were conducted under the conditions with or without GDP (1 mmol/L), respectively. RESULTS: For exposed to hypoxia, Bmax and the oxidative consumption of uncoupling respiration were increased. Kd, MMP and RCR were decreased. UCPs activity was inhibited by GDP in three groups. Kd was increased 61.01%, 83.13% and 71.52% and Bmax was decreased 23.18%, 35.20% and 33.38%, respectively. The values in the acute hypoxic group were changed markedly. The sensitivity of UCPs to GDP was elevated significantly by hypoxia. With the reducing of UCPs activity, oxidative consumption of uncoupling respiration was decreased whereas RCR and MMP were increased. The results elucidated increase in the efficiency of oxidative phosphorylation.CONCLUSION: GDP increases the mitochondrial membrane potential and decreases the oxygen consumption of uncoupling respiration in hypoxic exposed rat brain mitochondria by inhibiting UCPs activity. The results suggest that the change in UCPs activity is one of the factors of mitochondrial dysfunction in oxidative phosphorylation induced by hypoxia.

AIM: To explore the changes of myocardial energy metabolism and adenine nucleotide translocase (ANT) activity in mitochondria in rats exposed to hypoxia. METHODS: Adult male Wistar rats were exposed to simulated high altitude at 5 000 m for control (0 d), 1 d, 5 d, 15 d, 30 d in hypobaric chamber. Myocardial mitochondria were isolated by centrifugation. Mitochondria respiratory function was measured by Clark oxygen electrode. The size of adenine nucleotides pool (ATP, ADP, AMP) in mitochondria were separated and measured by HPLC. ANT activity was measured by [3H]-ADP incorporation. RESULTS: Compared to control, mitochondria state Ⅲ respiratory (ST_3) and RCR decreased and ST_4 increased sharply at 1 d, 5 d and 15 d, ST_3 still lower than that in control at 30 d, while RCR level restored. ATP contents and ANT activity decreased at 1 d and 5 d, then restored to control level at 15 d, then decreased again at 30 d. CONCLUSION: The inhibition of mitochondria respiratory function is the main reason that makes ATP contents decrease during hypoxic exposure. ANT activity and ATP content change cooperatively.

Objective To explore the changes of expression levels of 12S rRNA and cytochrome oxidase subunit Ⅰ (COXⅠ) mRNA encoded by mtDNA in rat cerebral cortex after rat exposure to hypobaric hypoxia for different days. Methods Healthy male Wistar rats were exposed to hypobaric chamber simulating 5 000 m above sea level (23 5 h/day) for 2, 5, 15 and 30 d. Rats in the control group were not exposed to hypoxia. Rats were sacrificed by decapitation. Total RNA in cerebral cortex was extracted using a standard program. Transcriptional levels of 12S rRNA and COXⅠ mRNA were determined by reverse transcription polymerase chain reaction (RT PCR). Results Compared with that in the control, the expression of 12S rRNA increased by 57% after hypoxic exposure for 2 d ( P 0 05). Compared with that in the control group, the expression of COXⅠ mRNA increased significantly by 55% and 106% after hypoxic exposure for 2 and 5 d ( P 0 05). Conclusion Hypoxic exposure may have effect on both protein gene and ribosome gene expression encoded by mtDNA, and the expression changes in a hypoxic exposure time dependent manner. This suggests that hypoxia can have effect on mitochondrial oxidative phosphorylation gene expression at both mitochondrial transcriptional and translational levels.

Objective To understand the changing aspects of CAP-administration on mitochondrial oxidative phosphorylation function and cytochrome c oxidase (COX) activity during hypoxia exposure and their mechanisms. Methods Except the control group (C group), adult male Wistar rats were exposed to a hypobaric chamber simulated 5 000-meter high altitude for 23 h every day for 0, 1, 5, 15, 30 d (H_ 0, 1, 5, 15, 30 ) respectively and administrated CAP (100 mg/kg, intraperitoneal injection) every 12 h for 7 d before sacrificed by decapitation. Mitochondrial respiratory function and COX activity were measured by Clark oxygen electrode and polarography, respectively. Results As compared with C group, mitochondrial state 3 respiration (ST_3) and respiratory control rate (RCR) and oxidative phosphorylation rate (ORP) and COX activity in H_0+CAP group all decreased significantly, but by prolonging hypoxia exposure increased and restored to the control level. Conclusion Mitochondrial respiratory function, oxidative phosphorylation efficiency and COX activity in rat brain could improve by administrating CAP during hypoxia exposure and almost reach to the control level by prolonging hypoxia exposure.

Objective To observe the changes of rat brain mitochondrial uncoupling protein (UCP) content and activity, and explore the effect of UCP on mitochondrial energy metabolism during hypoxia exposure. Methods Adult SD rats were set randomly into control and hypoxia group (n=8 in each group). The rats of hypoxia group were put into a hypobaric chamber simulating 5000-meter high altitude for 3 days (23 h/d). The brain mitochondria was isolated by centrifugation. Mitochondrial oxidative respiratory function was measured by Clark oxygen electrode. Mitochondrial membrane potential was detected by Rhodamine123 method. The content of adenine nucleotide pool (ATP, ADP, AMP) in mitochondria was measured by high performance liquid chromatography. UCP content and activity were detected by [~ 3 H]-GTP binding method. Results High altitude hypoxia resulted in significant increase of UCP activity and a 2.9-fold rise of UCP content of rats (P