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Proceeding from the requirements of teaching target for postgraduate students,the course of progress in pathophysiology was constructed and administrated.The course objective was defined which combined teaching knowledge with fostering students' ability together,especially the ability to think new ideas and to do scientific research.Aiming at this teaching target,the teaching contents which combined with the direction of scientific research of the department was growing together with scientific development,especially in new knowledge and new technique.Multiple teaching means and several mode of examine were adopted during the process of teaching practice.
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ial of cells. It may serve as an index for monitoring and prognostic diagnosis of breast cancer.
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<p><b>BACKGROUND</b>Mitochondrial DNA (mtDNA) is the only hereditary substance besides nucleus, which is composed of a code region and a non-code D-loop region. The aim of this study is to investigate the hypervariable region II (HVRII) mutation of mtDNA in peripheral blood leucocyte, pericancerous tissues and cancer tissues of lung squamous cell carcinoma patients, and to explore its significance.</p><p><b>METHODS</b>White blood cells, pericancerous tissues and cancer tissues were obtained from 15 cases of lung squamous cell carcinoma patients and mtDNA were extracted by one step method. HVRII fragments were amplified by PCR. Mutations were determined by DNA sequencing and the mutations of HVRII were analysed.</p><p><b>RESULTS</b>In 15 lung squamous cell carcinoma patients, 14 patients showed mutation in HVRII(93.33%), 88 mutations were found totally. Eighty-seven mutations located in H-strand origin region, especially in the conserved sequence blocks and the mtTF1, 2 binding site (TFX and TFY).</p><p><b>CONCLUSIONS</b>The results suggest that the mutation frequency of HVRII in cancer tissues of lung squamous cell carcinoma patients is very high and it might play an important role in carcinogenesis of the lung.</p>
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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.
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Objective To investigate the roles of mitochondrial DNA (mtDNA) in the respiratory function of cerebral mitochondria in rats exposed to acute hypoxia by observing the changes of mitochondrial respiratory function and cytochrome C oxidase (COX) activity. Methods The rat cerebral cortex mitochondria were isolated by centrifugation. Mitochondrial respiratory function and COX activity were measured by Clark oxygen electrode. Results ① Compared with the control group (C), hypoxia group (H) showed significantly elevated state 4 respiration (ST4), decreased state 3 respiration (ST3), and respiratory control rate (RCR). ② ST3 in group of treatment with chloramphenicol (CAP) plus hypoxia (MH) was significantly lower than that in Group C, while ST4 in Group MH was significantly lower than that in groups C and H. RCR in Group MH was lower than that in Group C, but higher than that in Group H. ③ COX activity in Group H was significantly lower than that in Group C. In Group MH, COX activity was higher than that in Group H, but was still lower than that in Group C. Conclusion The complete expression of mtDNA may play an important role in mitochondrial respiratory function. CAP treatment might be beneficial to the recovery of rat respiratory function.
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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.
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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
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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.
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Aim To understand the changing aspects of CAP-administration on expression of cytochrome C oxidase(COX) subunits I and IV and their mechanisms regulated by gene expression encoded by mtDNA and nDNA. Methods Wistar rats were randomly divided into control and CAP groups, Rats were administrated CAP(100 mg?kg -1, intraperitoneal injection) every 12 hours for 7 days before sacrificed by decapitation. Rat brain was removed and the cerebral cortex mitochondria was isolated by centrifugation programme. The protein content of COX subunitⅠand Ⅳ in mitochondria and NRF-1 in cerebral tissues was detected by Western blot analysis. And mRNA state levels of COXⅠ, COXⅣ, mtTFA and NRF-1 in tissues were determined by RT-PCR.Results Compared with C group, a decreased protein content of COX subunitⅠand an elevated ratio of subunit Ⅳ/Ⅰwas observed in CAP group, The protein content of COX subunit Ⅳ and NRF-1 as well as COXⅠ,Ⅳ,NRF-1 and mtTFA mRNA state level was not unchanged between the two groups. Conclusion The change of content of COX subunitⅠprotein in mitochondria from cerebral cortex showed there is no regulation of feedback to mitochondrial and nuclear transcription. The nuclear genomes expression does not correspond to mitochondrial expression in CAP-administrated rats.
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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.
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AIM:To explore the characteristics of energy metabolism in brain mitochondria of rats exposed to acute and chronic hypoxia. METHODS: Animal grouping: Wistar rats were randomized into acute hypoxic group (AH), chronic hypoxic group (CH) and the control. Respiratory function, F 0F 1-ATPase activity, mitochondrial ATP, ADP and AMP contents and ATP production rate were measured respectively. RESULTS: In AH, brain mitochondrial respiratory state IV (ST 4) was increased, while respiratory control rate (RCR), mitochondrial ATP content, ATP production rate and F 0F 1-ATPase activity were decreased respectively. In CH, ST 4, RCR, mitochondrial ATP content and F 0F 1-ATPase activity were reversed partially. CONCLUSION: Acute hypoxia may impair brain mitochondria energy metabolism by way of depressing mitochondrial oxidative phosphorylation and ATP production and these parameters gain partial reablement during chronic hypoxia.
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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.
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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.
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AIM: To investigate the effect of simulated high altitude hypoxia on rat brain mitochondrial translation activity. METHODS: Animals were continuously exposed to simulated 4 000 m high altitude in hypobaric chamber for three days and forty days. Mitochondria of rat brain were isolated by homogenizing brain tissue and following centrifuging program. Protein translation activity in isolated mitochondria in vitro was measured with -Lencine incorporation method. Products labeled with -methionine in isolated mitochondrial protein synthesis system in vitro were separated on SDS-PAGE and identified by autoradiography. RESULTS: Mitochondrial translation activity in vitro in acute hypoxia exposure were significantly lower than control( P
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Objective To investigate effect of guanosine diphosphate (GDP) on the mitochondrial respiratory oxygen consumption and the mitochondrial membrane potential (MMP) of rat brain and explore the relationship of the change of uncoupling proteins (UCPS) activity with the oxygen consumption and MMP. Methods The mitochondria of rat brain were isolated by centrifugation. Mitochondria oxidative respiratory consumption was measured by Clark electrode after the treatment of GDP at different concentrations so as to calculate mitochondrial state 3 respiration (ST3), mitochondrial state 4 respiration (ST4), respiratory control rate (RCR), and the rate of oxidative phosphorylation (OPR). MMP was detected by Rhodamine 123 method at the different concentrations of GDP. Results With the increase of GDP concentration form 0 to 1.0 mmol/L, the values of ST3, ST4 and OPR were reduced while RCR was elevated. But when the concentration increased to 1.4 mmol/L, the former 3 indexes begun to increase while the later declined. When the GDP concentration reached to 1 mmol/L, the inhibitory rate was only 35.1%, 51.3%, 14.2% to ST3, ST4 and OPR respectively, while RCR was increased to 133.2%. No matter the concentration was over 1 mmol/L or under 1 mmol/L, the ability of inhibition was attenuated. MMP reached to the highest point when GDP exerted the highest inhibitory rate on mitochondrial respiratory oxygen consumption. Conclusion GDP, an inhibitor of UCPS, can regulate the respiratory oxygen consumption and MMP of the isolated rat brain mitochondrial directly in a dose-effect fashion. The change of UCPS activity can affect the respiratory oxygen consumption and MMP.
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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.
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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.