Normal reference values for magnetic resonance imaging measurements of the fetal internal jugular veins in middle and late pregnancy.

BACKGROUND: At present, there is a lack of normal magnetic resonance imaging (MRI) morphometric reference values for fetal internal jugular veins during middle and late pregnancy. OBJECTIVE: We used MRI to assess the morphology and cross-sectional area of the internal jugular veins of fetuses during middle and late pregnancy and to explore the clinical value of these parameters. MATERIALS AND METHODS: The MRI images of 126 fetuses in middle and late pregnancy were retrospectively analysed to determine the optimal sequence for imaging the internal jugular veins. Morphological observation of the fetal internal jugular veins in each gestational week was carried out, lumen cross-sectional area was measured and the relationship between these data and gestational age was analysed. RESULTS: The balanced steady-state free precession sequence was superior to other MRI sequences used for fetal imaging. The cross section of fetal internal jugular veins was predominantly circular in both the middle and late stages of pregnancy, however the prevalence of an oval cross section was significantly higher in the late gestational age group. The cross-sectional area of the lumen of the fetal internal jugular veins increased with increasing gestational age. Fetal jugular vein asymmetry was common, with the right jugular vein being dominant in the high gestational age group. CONCLUSION: We provide normal reference values for fetal internal jugular veins measured by MRI. These values may form the basis for clinical assessment of abnormal dilation or stenosis.

The role of E2F1-topoIIß signaling in regulation of cell cycle exit and neuronal differentiation of human SH-SY5Y cells.

This study aims to test the role of E2F1-topoIIß signaling in neuronal differentiation of SH-SY5Y cells. With retinoic acid (RA) induction, a high percentage of cells were found to be arrested at the G0/G1 phase, with decreased levels of cyclinD1, CDK4, phosphorylation status of pRb and E2F1, in addition to an elevated level of p27. The cells were shown to differentiate into neuronal phenotypes characterized by highly expressed neuronal markers, MAP2 and enriched topoIIß, and remarkable neurite outgrowth. Exogenously forced E2F1 expression with a specific E2F1 plasmid led to suppression of topoIIß expression and disruption of the neuronal differentiation of SH-SY5Y cells. On further examination using the ChIP assay, we found that E2F1 bound directly to the promoter region of topoIIß, and its binding ability was inversely correlated with topoIIß expression in response to RA induction. Thus, our findings suggest that E2F1-topoIIß signaling may play a role in regulation of cell cycle exit and neuronal differentiation.

Immunohistochemical investigation of topoIIß, H3K27me3 and JMJD3 expressions in medulloblastoma.

Topoisomerase IIß (topoIIß) is a nuclear enzyme specifically expressed in neurons, and plays an important role in the development of the cerebellum. To date, the expression of topoIIß protein in medulloblastoma (MB) has not been investigated. In this study, 16 MB specimens including 10 classical subtypes of MB and 6 desmoplastic subtypes of MB (DMB), along with 5 normal cerebellum samples, were obtained from clinics. With immunohistochemical staining, prominently expressed topoIIß was seen in normal cerebellar tissues, while there was no or less pronounced staining in classical MB cells. Interestingly, on comparing topoIIß expression in different regions of DMB samples, relatively high levels of topoIIß were revealed within nodules composed of differentiated neurocytic cells, which are known to predict a favorable clinical outcome for MB. We also examined the expression of two epigenetic factors, H3K27me3 and JMJD3 in the different tissues. Very high levels of H3K27me3 were found in all MB samples, except the intranodules of DMB, where JMJD3 expression was more prominent. Furthermore, a negative correlation between topoIIß and H3K27me3 in MB was revealed in this study. Thus, our data primarily indicate that topoIIß can be used to estimate neuronal differentiation in MB, and may serve as a target for improving the survival rates for this condition. We speculate that H3K27me3 repression of topoIIß at the transcriptional level may occur, although this needs to be verified using larger numbers of MB samples in future experiments.

Tetramethylpyrazine induces SH-SY5Y cell differentiation toward the neuronal phenotype through activation of the PI3K/Akt/Sp1/TopoIIß pathway.

Tetramethylpyrazine (TMP) is an active compound extracted from the traditional Chinese medicinal herb Chuanxiong. Previously, we have shown that TMP induces human SH-SY5Y neuroblastoma cell differentiation toward the neuronal phenotype by targeting topoisomeraseIIß (TopoIIß), a protein implicated in neural development. In the present study, we aimed to elucidate whether the transcriptional factors specificity protein 1 (Sp1) and nuclear factor Y (NF-Y), in addition to the upstream signaling pathways ERK1/2 and PI3K/Akt, are involved in modulating TopoIIß expression in the neuronal differentiation process. We demonstrated that SH-SY5Y cells treated with TMP (80µM) terminally differentiated into neurons, characterized by increased neuronal markers, tubulin ßIII and microtubule associated protein 2 (MAP2), and increased neurite outgrowth, with no negative effect on cell survival. TMP also increased the expression of TopoIIß, which was accompanied by increased expression of Sp1 in the differentiated neuron-like cells, whereas NF-Y protein levels remained unchanged following the differentiation progression. We also found that the phosphorylation level of Akt, but not ERK1/2, was significantly increased as a result of TMP stimulation. Furthermore, as established by chromatin immunoprecipitation (ChIP) assay, activation of the PI3K/Akt pathway increased Sp1 binding to the promoter of the TopoIIß gene. Blockage of PI3K/Akt was shown to lead to subsequent inhibition of TopoIIß expression and neuronal differentiation. Collectively, the results indicate that the PI3K/Akt/Sp1/TopoIIß signaling pathway is necessary for TMP-induced neuronal differentiation. Our findings offer mechanistic insights into understanding the upstream regulation of TopoIIß in neuronal differentiation, and suggest potential applications of TMP both in neuroscience research and clinical practice to treat relevant diseases of the nervous system.

Lead Induces Apoptosis and Histone Hyperacetylation in Rat Cardiovascular Tissues.

Acute and chronic lead (Pb) exposure might cause hypertension and cardiovascular diseases. The purpose of this study was to evaluate the effects of early acute exposure to Pb on the cellular morphology, apoptosis, and proliferation in rats and to elucidate the early mechanisms involved in the development of Pb-induced hypertension. Very young Sprague-Dawley rats were allowed to drink 1% Pb acetate for 12 and 40 days. Western blot analysis indicated that the expression of proliferating cell nuclear antigen (PCNA) decreased in the tissues of the abdominal and thoracic aortas and increased in the cardiac tissue after 12 and 40 days of Pb exposure, respectively. Bax was upregulated and Bcl-2 was downregulated in vascular and cardiac tissues after 40 days of Pb exposure. In addition, an increase in caspase-3 activity was observed after 40 days of exposure to Pb. In terms of morphology, we found that the internal elastic lamina (IEL) of aorta lost the original curve and the diameter of cardiac cell was enlarged after 40 days. Furthermore, the exposure led to a marked increase in acetylated histone H3 levels in the aortas and cardiac tissue after 12 and 40 days, than that in the control group. These findings indicate that Pb might increase the level of histone acetylation and induce apoptosis in vascular and cardiac tissues. However, the mechanism involved need to be further investigated.

Specificity protein 1 regulates topoisomerase IIß expression in SH-SY5Y cells during neuronal differentiation.

Topoisomerase IIß (top IIß) is a nuclear enzyme with an essential role in neural development. The regulation of top IIß gene expression during neural differentiation is poorly understood. Functional analysis of top IIß gene structure displayed a GC box sequence in its transcription promoter, which binds the nuclear transcription factor specificity protein 1 (Sp1). Sp1 regulates gene expression via multiple mechanisms and is essential for early embryonic development. This study seeks to determine whether Sp1 regulates top IIß gene expression during neuronal differentiation. For this purpose, human neuroblastoma SH-SY5Y cells were induced to neuronal differentiation in the presence of all-trans retinoic acid (RA) for 5 days. After incubation with 10 µM RA for 3-5 days, a majority of the cells exited the cell cycle to become postmitotic neurons, characterized by the presence of longer neurite outgrowths and expression of the neuronal marker microtubule-associated protein-2 (MAP2). Elevated Sp1 and top IIß mRNA and protein levels were detected and found to be positively correlated with the differentiation stage. Chromatin immunoprecipitation assay demonstrated an increased recruitment of Sp1 to the top IIß promoter after RA treatment. Mithramycin A, a compound that interferes with Sp1 binding to GC-rich DNA sequences, downregulated the expression of top IIß, resulting in reduced expression of MAP2 and decreased neurite length compared with the control group. Our results indicate that Sp1 regulates top IIß expression by binding to the GC box of the gene promoter during neuronal differentiation in SH-SY5Y cells.

Mechanism of multidrug resistance of human small cell lung cancer cell line H446/VP.

BACKGROUND: Small cell lung cancer (SCLC) is the most aggressive form of lung cancer. This study aimed to investigate the mechanism of human small cell lung cancer cell line resistance to etoposide (VP-16), H446/VP. METHODS: The cell viability was measured by MTT assay. Immunocytochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting methods were used to detect the multidrug resistance gene (MDR1), bcl-2, bax and the topoisomerase II (Topo II) expressions in H446 and H446/VP cells after treated with or without VP-16. RESULTS: The 50% inhibition concentration (IC50) of VP-16 on H446 cells was 49 mg/L, and 836 mg/L was for H446/VP cells. The expressions of MDR1 and bcl-2 were up-regulated, while the amounts of bax and Topo II were reduced in H446/VP cells. After treated with 49 mg/L of VP-16, it showed that the drug could significantly inhibit bcl-2 and Topo II expressions, and increase bax expression in H446 cells compared with that of H446/VP cells. CONCLUSIONS: The H446/VP cell was stably resistant to VP-16. The decreased expression of Topo II was correlated with the H446/VP multidrug resistance. The elevated expressions of MDR1, and the altered apoptotic pathways also played an important role in VP-16 induced multidrug resistance of SCLC.

Overexpression of CD133 promotes the phosphorylation of Erk in U87MG human glioblastoma cells.

An increasing number of studies support the presence of stem-like cells in human malignancies. These cells are primarily responsible for tumor initiation and thus considered as a potential target to eradicate tumors. CD133 has been identified as an important cell surface marker to enrich the stem-like population in various human tumors. However, the biological function of CD133 protein remains unknown. In this study, we observed no significant effects on cell proliferation and migration in CD133 overexpressed U87MG human glioblastoma cells. It is reported that MAPK/Erk was constitutively activated in CD133 positive liver cancer stem cell. To find out possible mechanism between CD133 and Erk phosphorylation, we performed this study to evaluate the level of Erk phosphorylation in CD133 overexpressed U87MG cells. We found that CD133 overexpression significantly activated Erk, which suggested CD133 involved in activation of MAPK/Erk pathway.

[Left lower first premolar with 3 root canals: a case report].

3 root canals were found when a left lower first premolar, which preoperative radiograph showing root canal variety, was treated and were verified by postoperative radiograph. The root canal variety of lower premolars should be paid more attention to prevent root canal from losing.

[The dynamic changes of heme oxygenase-1 mRNA and protein express at subfornical organ in rats with experimental allergic encephalomyelitis].

AIM: To observe the dynamic changes of heme oxygenase-1 (HO-1) mRNA and protein express in subfornical organ in rats with experimental allergic encephalomyelitis (EAE) to confirm that SFO is one of the sites for blood-bearing signaling molecules entering into brain. METHODS: EAE was induced by CFA-GPSCH on Wistar rats, we observed the levels of HO-1 mRNA and its protein expression with immunohistochemistry and in situ hybridization technology on 1 d, 7 d, 14 d, and 21 d after EAE induction in SFO of rats. The relationship between HO-1 and symptoms of EAE was also investigated. RESULTS: The expression levels of HO-1 mRNA and its protein expression were very low in the brains of the control group, whereas they were enhanced gradually with pathological course in the brain and onsets of symptoms, signs of EAE. On 1 d after induction of EAE, positive cells of HO-1 mRNA and its protein expression were observed at SFO, but the labeled cells were rarely seen in the other brain regions. On 7 d, the positive cells increased markedly. On 14 d the levels of HO-1 mRNA and its protein expression in the brains reached the peak, the positive cells of HO-1 were mainly located at the choroid plexuses and SFO, as well as the regions around "sleeve-like" lesion foci, all of which were coincident with the locations of lesions of EAE. The changes of incidence, symptom, reduction of the body weight, and pathology lesions of EAE in rat brains were the most significant. On 21 d, the levels of HO-1 mRNA and its protein expression reduced gradually, which was in parallel with remitted symptoms of EAE. When a specific inhibitor of HO-1, Snpp9, was applied, the symptoms and pathological lesions of EAE in brains were mitigated markedly. CONCLUSION: SFO may be one of the earliest sites for blood-bearing signaling molecules entering into brain. The dynamic changes of HO-1 mRNA and its protein expression are in parallel with the changes of symptoms and pathological lesions of EAE in the brains. Application of some inhibitors of HO-1 may be one of potential therapeutic methods for prevention and treatment of EAE.

[The role of activation of nuclear factor-kappa B of rat brain in the pathogenesis of experimental allergic encephalomyelitis].

To investigate the role of activated nuclear factor-kappaB (NF-kappaB) in experimental allergic encephalomyelitis (EAE), the activity and protein expression of NF-kappaB p65 in rat brain tissues, which were extracted from EAE rats at 1, 7, 14 and 21 d respectively after EAE was induced by CFA-GPSCH, were measured with electrophoretic mobility shift assay and immunohistochemistry. The relationship between activated NF-kappaB and symptoms of EAE was also investigated. The results showed that protein expression level and the activity of NF-kappaB were very low in the brain of the control group. After EAE was induced, the activity of NF-kappaB and the level of the protein expression in the brains increased gradually with the development of symptoms and brain pathology of EAE. On d 14, both the activity and the level of protein expression in the brains reached a peak, the positive cells of NF-kappaB were mainly located at the choroid plexuses and subfornical organ, as well as around the regions of sleeve-like lesion foci, which were coincident with the locations of lesions of EAE. The incidence, symptoms, reduction of the body weight and pathology of EAE rats brains at the above locations were most significant. On d 21 the activity of NF-kappaB and level of the protein expression reduced gradually, which was in parallel with a gradual alleviation of the symptoms of EAE rats. After a specific inhibitor of NF-kappaB, PDTC was applied, the symptoms and pathological lesions of EAE rat brain were mitigated markedly. The above results indicate that the dynamic changes in the activity and protein expression of NF-kappaB were in parallel with the changes in symptoms and pathological lesion of EAE rat brains. In conclusion, the activated NF-kappaB in the brain may play a critical role in the pathogenesis of EAE, and application of some inhibitors of NF-kappaB, such as PDTC, may be one of the effective therapeutic methods for prevention and treatment of EAE.