The finding and research on yeast prion are of great values for biology and medical sciences.Research advances in molecular chaperones, especially in Hsp104p, Hsp70p and Hsp40p, regulating yeast prion [PSI+] propaga-tion,are reviewed.

Objective To study the effects of midkine (MK) gene-targeting small interfering RNA (siRNA)on the invasion of melanoma cells.Methods Three MK gene-targeting siRNAs (S1,S2 and S3)were designed,constructed,and transfected into human A375 melanoma cells.Real-time PCR was performed to measure the expression of MK gene and to screen the siRNA with best efficacy.Then,A375 cells were transfected with the optimal siRNA of various doses (3.125,6.25 and 12.5 nmol/L)followed by additional culture of various durations(24,48,72 hours).Some A375 cells remaining untreated served as the blank control group,and some transfected only with liposomes served as the vector control group.Reverse transcription (RT) -PCR and Western blot were conducted to detect the mRNA and protein expression of MK,respectively,MTT assay to observe the adhesion of A375 cells,and Boyden chamber was used to evaluate cell invasion.Results The expression of MK mRNA was downregulated by all the three siRNAs,especially by the siRNA S3,which was used in the following transfection experiment.Real-time quantitative PCR revealed that the MK mRNA expression was reduced by the siRNA in a dose- (r24hours=-0.906,r4Bhours=-0.922,r72hours=-0.939,all P<0.01)and time-dependent(r3.125nmol/L=-0.889,r625nmol/L=-0.935,r125nmol/L=-0.928,all P<0.01)manner.MTT assay showed that the percentage of adhesing cells was 73.66%±2.25%,49.36%±2.16%and 28.35%±1.68%in A375 cells transfected with the siRNA of 3.125,6.25 and 12.5 nmol/L,respectively.The number of cells migrating across the chamber filter was 23.9±1.6,12.1±1.5,5.6±1.2 among A375 cells transfected with the siRNA of 3.125,6.25 and 12.5 nmol/L,respectively,significantly lower than that in the blank control group(36.8±1.5).The percentage of adhesing cells and number of migrating cells decreased with the dose of siRNA(r=-0.936,-0.915,P<0.01,0.05,respectively).Conclusions MK gene might play an important role in the adhesion and invasion of melanonla cells.To down-regulate the expression of MK gene by siRNA may suppress the adhesion and invasion of melanoma cells.

Objective To study the effects of Forkhead box protein M1 (FoxM1) down regulation by small interfering RNA(siRNA) on chemosensitivity and mechanism of human pancreatic cancer cell and its mechanism.Methods Three FoxM1 siRNAs were designed and constructed.All cancer cells were divided into different groups,after transfected with FoxM1 siRNA for different time,the cultured cells were harvested to carry on the next tests.Expression of FoxM1 were determined by red-time PCR and Western blot,and prolifearion and chemosensitivity were evaluated by MTT assay,and the phosphorylation of Akt protein was examined by Western blot.Results FoxM1 siRNA could down-regulate the FoxM1 expression in a dose-and time-dependent manner.The MTF results showed that the inhibit rates was 17.78％,17.56％,35.39％,52.81％,70.98％ indifferentgroups [Con-A + Gemcitabine,Con-B + Gemcitabine,siRNA (3.125nM) + Gemcitabine,siRNA (6.25nM) + Gemcitabine and siRNA(12.5nM) + Gemcitabine,respectively.The phosphorylation of Akt protein was inhibited in a dose-dependent manner.Conclusions FoxM1 siRNA could sensitize human pancreaticr cancer cells chemotherapy sensitivity,it is the one of the important mechanisms through down-regulate Akt phosphorylated levels,but the molecular mechanism need to be explored further.

Humans are exposed to the ubiquitous radiofrequency (RF, 100 kHz-300 GHz) electromagnetic fields because of the mushroom development of wireless communications,raising concerns over the possible hazards of RF radiations.Epidemiological investigation has showed that chronic use of cellphones increases the risk of brain tumors.Since genetic damage is closely related to tumors, researchers have been trying to find out whether cellphones and other RF devices are genotoxic.However, the investigations have yielded both negative and positive results.This review summarized the recent in vitro and in vivo researches about genotoxicity of RF radiations and proposed a possible mechanism by which of RF radiations cause genetic damage.

BACKGROUND:Olfactory ensheathing cells (OECs) have been shown to possess the potential of repairing injured spinal cord, but their biological characteristics after transplantation in vivo are not well understood.OBJECTIVE: To investigate the migration of OECs after transplantation into the injured spinal cord of adult rats.DESIGN: Randomized and controlled experiment.SETTING: Department of Orthopedics, Guangdong Provincial People's Hospital; Experimental Animal Center of the North Campus of Sun Yat-sen UniversityMATERIALS: Totally 38 2-month-old male SD rats with body mass of (350 ±20) g were used in this study.METHODS: This experiment was conducted in the Experimental Animal Center, North Campus of Sun Yat-sen University between February 2004and May 2004. Two SD rats were used to extract the OECs, which were stained with Hoechst 33342. Totally 36 SD rats were subsequently randomized into 3 groups, namely rostral transplantation group, caudal transplantation group and control group with 12 rats in each group. The rats in the rostral and caudal transplantation groups subjected to operations to establish thoracic spinal cord injury model and OEC suspension was injected; in the control group, the rats were spared of thoracic spinal cord injury with only OEC suspension injection.MAIN OUTCOME MEASURES: Distribution of OECs in the spinal cord was observed under fluorescence microscope 1, 2, 4 and 6 weeks after operation, respectively.RESULTS: Of the rats in the 3 groups, 1 died in the rostral group, and 2in each of the caudal transplantation and control groups, leaving 29 rats for result analysis. The OECs in the rostral and caudal transplantation groups migrated longitudinally along the long axis of the spinal cord to a farthest distance of 8 mm and penetrating the scar tissues, but very few cells could reach the contralateral side. The OECs in the control group diffused locally without migration.CONCLUSION: OECs mainly migrate along the axons in white matter of the injured spinal cord, and their rostral and caudal migration does not differ in speed or amount. Only a small amout of OECs can across the transected gap of the spinal cord.

Objective To investigate the operation key points, instrument improvement and shortterm effects in total en bloc spondylectomy (TES) via a single posterior approach for thoracic and lumbar tumors. Methods A series of modified instruments have been designed for the TES, including threadwire saw (T-saw) with a diameter of 0.81 mm, director and clamping for the saw, L shape and furcation osteotomes.The corpectomy of original TES which was defined as "one step dissection" from anteriorly to posteriorly, was modified into "two step dissection" which means that corpectomy was performed with saw cutting anteriorposteriorly and the L shape cutting posterior-anteriorly. In the cases with difficulty in pediculotomy using a T-saw, furcation osteotome was used for pediculotomy. Ten patients with thoracic or lumbar tumors were treated with the modified TES. There were 1 case of bone giant cell tumor, 1 case of bone neurilemmoma and 8 cases of metastatic tumors. All patients suffered moderate-severe pain and neurological deficit. Results The average follow-up period was 8.1(3.3-18.1) months. The average operating time was 7.8 h(6.0-10.3 h),and average blood loss was 2100 ml (1200-3500 ml). No disruption of dural mater, the leakage of cerebrospinal fluid, iatrogenic spinal cord injury and major vessel damage occurred. Two patients who underwent pleura disruption happened during the operation were treated with intrathoracic drain remedy. Among 7 cases with thoracic tumors, significant improvement in neurological function were achieved in 5 patients with the improvement of one grade in ASIA classification, while no change was found in 2 cases. In 3 cases with lumbar tumor, lumbar nerve root pain relieved and the muscle strength had recovered to grade 4 at least postoperatively. Conclusion Significant improvement has been achieved in the maneuverability and safety of the modified surgical techniques in TES with a single posterior approach for thoracic and lumbar tumors.

Objective To study the incidence and prognosis of avascular necrosis after talus fracture. Methods A retrospective survey was performed in 12 patients ( 13 feet) with talus fractures admitted into hospital from July 2004 to November 2009 to analyze necrosis rate, ankle function recovery and disability rate. According to Hawkin' s classification system, there were two patients with type Ⅰ feet, four with type Ⅱ feet, five with type Ⅲ feet and two with type Ⅳ feet. Results All patients were followed up for average period of 19.6 months (range 11-52 months). Avascular necrosis was detected in eight feet, of which one foot was treated with ankle fusion, one with subtalar arthrodesis and one with bone implantation. The other five feet had good ankle and subtalar function, with no collapse or osteoarthritis. According to Maryland foot score, the result was excellent in eight patients, good in two, fair in one and failure in two, with excellence rate of 77%. Conclusion The incidence of avascular necrosis after talus fracture is related to the location and energy of trauma. However, the function prognosis of the talus shows no correlation with necrosis.

Objective To investigate the effects of miR-10a expression on migration and invasion of human pancreatic cancer cells AsPC-1.Methods Small interfering RNA targeting at miR-10a (miR-10a-siRNA) was constructed,then it was transfected into pancreatic cancer AsPC-1 cells,and nonsense siRNA (Nc-siRNA) group and blank control group was established.Real time PCR assay was used to detect the expression of miR-10a in the 3 groups,and wound healing assay and Transwell assay were used to determine the migration and invasion abilities of cancer cells.The amount of matrix metalloproteinase-13 (MMP-13) in supernatant of cancer cell culture of each group was examined by ELISA assay.Results The miR-10a levels in control group,NC-siRNA group and miR-10a-siRNA group were 1.05 ±0.08,1.03 ±0.06,0.02 ±0.01 ; and the number of transmembrane cell were (150 ± 2.6),(145 ± 2.2),(62 ± 1.8),the levels of MMP-13 in the supernatant were (108.5 ± 2.8),(107.8 ± 2.5),(35.8 ± 1.5) pg/ml.The values were significantly lower in miR-10a-siRNA group than those in control group and NC-siRNA group (P ＜ 0.01).The distance of cultured clone in miR-10a treated cancer cells (736± 18 μm) was significantly longer than those in the controls (385 ±5 μm) and NC-siRNA group (395± 13 μm,P＜0.01).Conclusions Down-regulation of miR-10a by siRNA may inhibit migration and invasion of pancreatic cancer AsPC-1 cells,and the downregulated expression of MMP-13 may be one of the important mechanisms.

BACKGROUND:Pain is the main clinical manifestation for ankylosing spondylitis. At present, nonsteroid anti-inflammatory drugs are oral y taken, but the effects are limited and toxic and side effects are more. Thus, there is no effective scheme for treatment of pain induced by ankylosing spondylitis.
OBJECTIVE:To investigate the correlation between postoperative joint pain al eviation and al ogeneic blood transfusion, and the mechanisms.
METHODS:We retrospectively analyzed clinical data of 88 ankylosing spondylitis patients combined with kyphosis who received only one section of osteotomy surgery merging hip joint pain. We compared the visual analog scale score of hip joint and detected the variation of leucocytes, lymphocytes and immunoglobulin concentrations before and after the operation in the groups of fresh al ogeneic whole blood transfusion, autologous whole blood transfusion, and mixed transfusion of al ogeneic and autologous whole blood. Flow cytometry was used to analyze the number and ratio of peripheral blood Th17 cells and Treg cells which were both highly associated with autoimmune diseases.
RESULTS AND CONCLUSION:The symptom of hip arthralgia obviously improved in both groups transfused by fresh al ogeneic whole blood or al ogeneic-autologous mixed whole blood. However, no obvious variation was detected in leucocytes, lymphocytes and immunoglobin concentration. However, flow cytometry results indicated that Th17/Treg proportion associated with autoimmune diseases was increased remarkably in peripheral blood of ankylosing spondylitis patients. Results suggested that al ogeneic whole blood transfusion can al eviate patients’ joint pain by correcting the imbalance of Th17/Treg which may improve their immune state.

BACKGROUND:Ankylosing spondylitis is an autoimmune disease at high inflammatory state, and its pathogenesis is stil unclear. Besides, there is a lack of entirely satisfactory curative strategies. OBJECTIVE: To explore the immunoregulation capability of bone marrow mesenchymal stem cels from ankylosing spondylitis patients on macrophages and the potential therapeutic use of bone marrow mesenchymal stem cels from healthy donors on ankylosing spondylitis. METHODS: Bone marrow mesenchymal stem cels were extracted from 21 healthy donors and 25 ankylosing spondylitis patients respectively, and passage 4 cels were used in subsequent experiments. A human monocytic cel line was induced to differentiate into macrophages. The phenotypic markers of bone marrow mesenchymal stem cels and macrophages were detected by flow cytometry. Expressions of tumor necrosis factor-α and tumor necrosis factor-α-stimulated gene 6 (TSG-6) proteins in the supernatant of co-culture system were detected by ELISA. Quantitative real-time PCR was applied to detect the mRNA level of cytokines secreted by bone marrow mesenchymal stem cels and macrophages. RESULTS AND CONCLUSION:The typical mesenchymal stem cel surface markers were expressed in both bone marrow mesenchymal stem cels from healthy donors and patients with ankylosing spondylitis, and CD68 was detected positively in induced macrophages. The protein and mRNA levels of tumor necrosis factor-α secreted by macrophages co-cultured with bone marrow mesenchymal stem cels from patients with ankylosing spondylitis were obviously higher than those from healthy donors (P < 0.05). TSG-6 secreted by bone marrow mesenchymal stem cels from patients with ankylosing spondylitis was lower than that by bone marrow mesenchymal stem cels from healthy donors in both RNA transcriptional and protein levels (P < 0.05). Our study demonstrates that bone marrow mesenchymal stem cels from patients with ankylosing spondylitis shows abnormal immunoregulatory function on inhibiting the tumor necrosis factor-α secretion from macrophages, which reveals a mechanism of immune disorder in ankylosing spondylitis. The therapeutic mechanism of bone marrow mesenchymal stem cels from healthy donors may work by secreting enough TSG-6 to inhibit the activation of macrophages in patients with ankylosing spondylitis, and thereby to decrease the secretion of tumor necrosis factor-α. Cite this article:Sun SH, Wang P, Su CY, Xie ZY, Li YX, Li D, Wang S, Su HJ, Wu XH, Deng W, Wu YF, Shen HY. Bone marrow mesenchymal stem cels derived from patients with ankylosing spondylitis show abnormal immunoregulation capability on macrophages. Zhongguo Zuzhi Gongcheng Yanjiu. 2016;20(1):13-19.