Objective: To observe whether there is evidence for vascular channel formation by osteosarcoma cellsin vitro and to illustrate mechanism of vasculogenic mimicry in osteosarcoma.Methods: Osteosarcoma cell lines (U-2OS)...Objective: To observe whether there is evidence for vascular channel formation by osteosarcoma cellsin vitro and to illustrate mechanism of vasculogenic mimicry in osteosarcoma.Methods: Osteosarcoma cell lines (U-2OS) were tested for their ability to form tubular networks in three-dimensional culture containing type I collagen. The structures of the tubular networks were observed under a phase contrast microscope and an electron microscope.Results: Observation under light microscopy and electron microscopy showed that high aggressive osteosarcoma cells line (U-2OS) formed networks containing channels when grown in three-dimensional culture containing type I collagen in the absence of endothelial cells or fibroblasts.Conclusion: These observations strongly suggest that aggressive osteosarcoma cells may generate vascular channels that facilitate tumor perfusion independent of tumor angiogenesis and have the ability of vasculogenic mimicry. Key words osteosarcoma cells line - vasculogenesis mimicry - angiogenesis - 3-dimensional cultures This study was supported in part by the National Natural Sciences Foundation of China (No. 30271314).展开更多
AIM： To explore the relationship between DNA methyltransferase 1 （DNMT1） and hepatitis B virus （HBV）-related hepatocellular carcinoma （HCC） and its biological significance in primary HCC. METHODS： We carried o...AIM： To explore the relationship between DNA methyltransferase 1 （DNMT1） and hepatitis B virus （HBV）-related hepatocellular carcinoma （HCC） and its biological significance in primary HCC. METHODS： We carried out an immunohistochemical examination of DNMT1 in both HCC and paired nonneoplastic liver tissues from Chinese subjects. DNMT1 mRNA was further examined in HCC cell lines by real-time PCR. We inhibited DNMT1 using siRNA and detected the effect of depletion of DNMT1 on cell proliferation ability and cell apoptosis in the HCC celt line SMMC-7721. RESULTS： DNMT1 protein expression was increased in HCCs compared to histologically normal nonneoplastic liver tissues and the incidence of DNMT1 immunoreactivity in HCCs correlated significantly with poor tumor differentiation （P = 0.014）. There were more cases with DNMT1 overexpression in HCC with HBV （42.85%） than in HCC without HBV （28.57%）. However, no significant difference in DNMT1 expression was found in HBV-positive and HBV-negative cases in the Chinese HCC group. There was a trend that DNMT1 RNA expression increased more in HCC cell lines than in pericarcinoma cell lines and normal liver cell lines. In addition, we inhibited DNMT1 using siRNA in the SMMC-7721 HCC cell line and found depletion of DNMT1 suppressed cells growth independent of expression of proliferating cell nuclear antigen （PCNA）, even in HCC cell lines where DNMT1 was stably decreased. CONCLUSION： The findings implied that DNMT1 plays a key role in HBV-retated hepatocellular tumorigenesis. Depletion of DNMT1 mediates growth suppression in SMMC-7721 cells.展开更多
Neural stem cells （NSCs） constitute the cellular basis for embryonic brain development and neurogenesis. The process is regulated by NSC niche including neighbor cells such as vascular and glial cells. Since both va...Neural stem cells （NSCs） constitute the cellular basis for embryonic brain development and neurogenesis. The process is regulated by NSC niche including neighbor cells such as vascular and glial cells. Since both vascular and glial cells secrete vascular endothelial growth factor （VEGF） and basic fibroblast growth factor （bFGF）, we assessed the effect of VEGF and bFGF on NSC proliferation using nearly homogeneous NSCs that were differentiated from mouse embryonic stem cells. VEGF alone did not have any significant effect. When bFGF was added, however, VEGF stimulated NSC proliferation in a dose-dependent manner, and this stimulation was inhibited by ZM323881, a VEGF receptor （Flk-1）- specific inhibitor. Interestingly, ZM323881 also inhibited cell proliferation in the absence of exogenous VEGF, suggesting that VEGF autocrine plays a role in the proliferation of NSCs. The stimulatory effect of VEGF on NSC proliferation depends on bFGF, which is likely due to the fact that expression of Flk-1 was upregulated by bFGF via phosphorylation of ERK1/2. Collectively, this study may provide insight into the mechanisms by which microenvironmental niche signals regulate NSCs.展开更多
It is shown that flow of a blood in a passive elastic tube essentially unstable process accompanying with a flutter of a stream. Biophysical principles of neuroreflex regulation of an arterial bloodstream in cardiovas...It is shown that flow of a blood in a passive elastic tube essentially unstable process accompanying with a flutter of a stream. Biophysical principles of neuroreflex regulation of an arterial bloodstream in cardiovascular system are considered. It is shown that this regulation has dual-purpose character： reduction of the hydraulic resistance and maintenance stable no flutter stream of blood. The reasons of a primary arterial hypertension occurrence, and also some accompanying it physical and physiological phenomena are considered. The surgical method of treatment of the primary arterial hypertension, connected with denervation of renal arteries is substantiated.展开更多
To investigate the expression characteristics of basic fibroblast growth factor （ bFGF ） and its receptors, fig （ FGFR1 ） and bek （ FGFR2 ）, in fetal skin at different gestational ages underlying the relevance o...To investigate the expression characteristics of basic fibroblast growth factor （ bFGF ） and its receptors, fig （ FGFR1 ） and bek （ FGFR2 ）, in fetal skin at different gestational ages underlying the relevance of these 3 proteins to skin development and the mechanisms underlying the phenotypic transition from scarless to scar- forming healing. Methods ： Eighteen specimens of fetal skin biopsies of human embryo were obtained from spontaneous abortions at different gestational ages of 13-32 weeks. Gene expression of bFGF, bek and fig was examined with reverse transcription-polymerase chain reaction （ RT-PCR ）. The dynamic expression and distribution of these 3 proteins were detected with streptavidin peroxidase （ SP ） immunohistochemical staining method. Results： In the early gestational fetal skin, genes of bFGF and fig were strongly expressed and more protein contents of these 2 proteins were found as compared with the genes at late gestation fetal skin （2.446 ± 0. 116 and 2.066±0.152 versus 2. 157± 0.101 and 1.818± 0.086, respectively, P 〈 0.05 ）. On the contrary, the levels of gene expression and protein content of bek were not differently expressed in the early gestational fetal skin versus the late ones. Protein particles of bFGF were mainly distributed in the epidermal cells and some fibroblasts. Bek was mainly located in the cell membrane and cytoplasm of epidermal cells while fig protein was principally located in the epidermal cells, endothelial cells and some fibroblasts. Conclusions： The endogenous bFGF and their refeptors might be involved in the cutaneous development at fetal stage. The differently expressing levels of bFGF and fig during gestation may be related to scarless or scarforming repair during gestation.展开更多
Primary blast-induced traumatic brain injury （bTBI） has been observed at the boundary of brain tissue and cerebrospinal fluid （CSF）. Such injury can hardly be explained by using the theory of compressive wave prop...Primary blast-induced traumatic brain injury （bTBI） has been observed at the boundary of brain tissue and cerebrospinal fluid （CSF）. Such injury can hardly be explained by using the theory of compressive wave propagation, since both the solid and fluid materials have similar compressibility and thus the intracranial pressure （ICP） has a continuous distribution across the boundary. Since they have completely different shear properties, it is hypothesized the injury at the interface is caused by shear wave. In the present study, a preliminary combined numerical and theoretical analysis was conducted based on the theory of shear wave propagation]reflection. Simulation results show that higher lateral acceleration of brain tissue particles is concentrated in the boundary region. Based on this finding, a new biomechanical vector, termed as strain gradient, was suggested for primary bTBI. The subsequent simple theoretical analysis reveals that this parameter is proportional to the value of lateral acceleration. At the boundary of lateral ventricles, high spatial strain gradient implies that the brain tissue in this area （where neuron cells may be contained） undergo significantly different strains and large velocity discontinuity, which may result in mechanical damage of the neuron cells.展开更多
Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine ...Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine traffic accident mortality trends and their epidemiologic characteristics in the Kermanshah province, west of lran. Methods： In a cross sectional study, road traffic fatality data from 2004 to 2013 were analyzed to determine the epidemiological pattern of traffic accident mortality. Trend assessment was performed to ascertain the decreasing or increasing status. Chi-square and one-way analysis of variance （ANOVA） tests, as well as Poisson regression were used to determine the significance of the data in time. Data were analyzed using Excel and statistical package of SPSS version 19. Results： Out of 5110 people that died in traffic accidents, 4024 （78.7%） were males. The state of accidents indicated that 404 （43.8%） female pedestrians died as a result of car crashes, and 1330 （41.4%） males died because of car collisions. 1554 （31.9%） deaths happened to pedestrians and 1556 （32.1%） to vehicle drivers, and the rest belonged to vehicle passengers. Head trauma was the cause of death for as much as 3400 （69.9%） cases. Fatal crashes in which pedestrians were involved mostly occurred between the hours 13：00 to 15：00, while the time for vehicle drivers was between 16：00 to 18：00. 2882 people （59.1%） died before reaching to health care facilities. Traffic crash mortality trend for pedestrians follows a linear pattern with a gentle downward slope, but the trend shows various swings when it comes to vehicle drivers. Conclusion： The number of traffic crash deaths from 2004 to 2013 indicates a decreasing trend in two groups of road users： vehicle drivers and car occupants. This can be due to some interventions such as modification of traffic rules and enhancement of police control which has been implemented in recent years. Moreover, more attention should be paid to promote the optimal health care services to save the lives of the injured from traffic accidents.展开更多
基金This study was supported in part by the National Natural Sciences Foundation of China(No.30271314).
文摘Objective: To observe whether there is evidence for vascular channel formation by osteosarcoma cellsin vitro and to illustrate mechanism of vasculogenic mimicry in osteosarcoma.Methods: Osteosarcoma cell lines (U-2OS) were tested for their ability to form tubular networks in three-dimensional culture containing type I collagen. The structures of the tubular networks were observed under a phase contrast microscope and an electron microscope.Results: Observation under light microscopy and electron microscopy showed that high aggressive osteosarcoma cells line (U-2OS) formed networks containing channels when grown in three-dimensional culture containing type I collagen in the absence of endothelial cells or fibroblasts.Conclusion: These observations strongly suggest that aggressive osteosarcoma cells may generate vascular channels that facilitate tumor perfusion independent of tumor angiogenesis and have the ability of vasculogenic mimicry. Key words osteosarcoma cells line - vasculogenesis mimicry - angiogenesis - 3-dimensional cultures This study was supported in part by the National Natural Sciences Foundation of China (No. 30271314).
基金Supported by National Natural Science Foundation of China,No.30470950
文摘AIM： To explore the relationship between DNA methyltransferase 1 （DNMT1） and hepatitis B virus （HBV）-related hepatocellular carcinoma （HCC） and its biological significance in primary HCC. METHODS： We carried out an immunohistochemical examination of DNMT1 in both HCC and paired nonneoplastic liver tissues from Chinese subjects. DNMT1 mRNA was further examined in HCC cell lines by real-time PCR. We inhibited DNMT1 using siRNA and detected the effect of depletion of DNMT1 on cell proliferation ability and cell apoptosis in the HCC celt line SMMC-7721. RESULTS： DNMT1 protein expression was increased in HCCs compared to histologically normal nonneoplastic liver tissues and the incidence of DNMT1 immunoreactivity in HCCs correlated significantly with poor tumor differentiation （P = 0.014）. There were more cases with DNMT1 overexpression in HCC with HBV （42.85%） than in HCC without HBV （28.57%）. However, no significant difference in DNMT1 expression was found in HBV-positive and HBV-negative cases in the Chinese HCC group. There was a trend that DNMT1 RNA expression increased more in HCC cell lines than in pericarcinoma cell lines and normal liver cell lines. In addition, we inhibited DNMT1 using siRNA in the SMMC-7721 HCC cell line and found depletion of DNMT1 suppressed cells growth independent of expression of proliferating cell nuclear antigen （PCNA）, even in HCC cell lines where DNMT1 was stably decreased. CONCLUSION： The findings implied that DNMT1 plays a key role in HBV-retated hepatocellular tumorigenesis. Depletion of DNMT1 mediates growth suppression in SMMC-7721 cells.
文摘Neural stem cells （NSCs） constitute the cellular basis for embryonic brain development and neurogenesis. The process is regulated by NSC niche including neighbor cells such as vascular and glial cells. Since both vascular and glial cells secrete vascular endothelial growth factor （VEGF） and basic fibroblast growth factor （bFGF）, we assessed the effect of VEGF and bFGF on NSC proliferation using nearly homogeneous NSCs that were differentiated from mouse embryonic stem cells. VEGF alone did not have any significant effect. When bFGF was added, however, VEGF stimulated NSC proliferation in a dose-dependent manner, and this stimulation was inhibited by ZM323881, a VEGF receptor （Flk-1）- specific inhibitor. Interestingly, ZM323881 also inhibited cell proliferation in the absence of exogenous VEGF, suggesting that VEGF autocrine plays a role in the proliferation of NSCs. The stimulatory effect of VEGF on NSC proliferation depends on bFGF, which is likely due to the fact that expression of Flk-1 was upregulated by bFGF via phosphorylation of ERK1/2. Collectively, this study may provide insight into the mechanisms by which microenvironmental niche signals regulate NSCs.
文摘It is shown that flow of a blood in a passive elastic tube essentially unstable process accompanying with a flutter of a stream. Biophysical principles of neuroreflex regulation of an arterial bloodstream in cardiovascular system are considered. It is shown that this regulation has dual-purpose character： reduction of the hydraulic resistance and maintenance stable no flutter stream of blood. The reasons of a primary arterial hypertension occurrence, and also some accompanying it physical and physiological phenomena are considered. The surgical method of treatment of the primary arterial hypertension, connected with denervation of renal arteries is substantiated.
基金This work was supported by the National Basic Science andDevelopment Program (973 Program, No.G1999054204)andthe National Natural Science Foundation of China ( No.30230370 and No. 30400172)
文摘To investigate the expression characteristics of basic fibroblast growth factor （ bFGF ） and its receptors, fig （ FGFR1 ） and bek （ FGFR2 ）, in fetal skin at different gestational ages underlying the relevance of these 3 proteins to skin development and the mechanisms underlying the phenotypic transition from scarless to scar- forming healing. Methods ： Eighteen specimens of fetal skin biopsies of human embryo were obtained from spontaneous abortions at different gestational ages of 13-32 weeks. Gene expression of bFGF, bek and fig was examined with reverse transcription-polymerase chain reaction （ RT-PCR ）. The dynamic expression and distribution of these 3 proteins were detected with streptavidin peroxidase （ SP ） immunohistochemical staining method. Results： In the early gestational fetal skin, genes of bFGF and fig were strongly expressed and more protein contents of these 2 proteins were found as compared with the genes at late gestation fetal skin （2.446 ± 0. 116 and 2.066±0.152 versus 2. 157± 0.101 and 1.818± 0.086, respectively, P 〈 0.05 ）. On the contrary, the levels of gene expression and protein content of bek were not differently expressed in the early gestational fetal skin versus the late ones. Protein particles of bFGF were mainly distributed in the epidermal cells and some fibroblasts. Bek was mainly located in the cell membrane and cytoplasm of epidermal cells while fig protein was principally located in the epidermal cells, endothelial cells and some fibroblasts. Conclusions： The endogenous bFGF and their refeptors might be involved in the cutaneous development at fetal stage. The differently expressing levels of bFGF and fig during gestation may be related to scarless or scarforming repair during gestation.
文摘Primary blast-induced traumatic brain injury （bTBI） has been observed at the boundary of brain tissue and cerebrospinal fluid （CSF）. Such injury can hardly be explained by using the theory of compressive wave propagation, since both the solid and fluid materials have similar compressibility and thus the intracranial pressure （ICP） has a continuous distribution across the boundary. Since they have completely different shear properties, it is hypothesized the injury at the interface is caused by shear wave. In the present study, a preliminary combined numerical and theoretical analysis was conducted based on the theory of shear wave propagation]reflection. Simulation results show that higher lateral acceleration of brain tissue particles is concentrated in the boundary region. Based on this finding, a new biomechanical vector, termed as strain gradient, was suggested for primary bTBI. The subsequent simple theoretical analysis reveals that this parameter is proportional to the value of lateral acceleration. At the boundary of lateral ventricles, high spatial strain gradient implies that the brain tissue in this area （where neuron cells may be contained） undergo significantly different strains and large velocity discontinuity, which may result in mechanical damage of the neuron cells.
文摘Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine traffic accident mortality trends and their epidemiologic characteristics in the Kermanshah province, west of lran. Methods： In a cross sectional study, road traffic fatality data from 2004 to 2013 were analyzed to determine the epidemiological pattern of traffic accident mortality. Trend assessment was performed to ascertain the decreasing or increasing status. Chi-square and one-way analysis of variance （ANOVA） tests, as well as Poisson regression were used to determine the significance of the data in time. Data were analyzed using Excel and statistical package of SPSS version 19. Results： Out of 5110 people that died in traffic accidents, 4024 （78.7%） were males. The state of accidents indicated that 404 （43.8%） female pedestrians died as a result of car crashes, and 1330 （41.4%） males died because of car collisions. 1554 （31.9%） deaths happened to pedestrians and 1556 （32.1%） to vehicle drivers, and the rest belonged to vehicle passengers. Head trauma was the cause of death for as much as 3400 （69.9%） cases. Fatal crashes in which pedestrians were involved mostly occurred between the hours 13：00 to 15：00, while the time for vehicle drivers was between 16：00 to 18：00. 2882 people （59.1%） died before reaching to health care facilities. Traffic crash mortality trend for pedestrians follows a linear pattern with a gentle downward slope, but the trend shows various swings when it comes to vehicle drivers. Conclusion： The number of traffic crash deaths from 2004 to 2013 indicates a decreasing trend in two groups of road users： vehicle drivers and car occupants. This can be due to some interventions such as modification of traffic rules and enhancement of police control which has been implemented in recent years. Moreover, more attention should be paid to promote the optimal health care services to save the lives of the injured from traffic accidents.
