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Aim To study the effect of tetrandrine derivative HL-49 on the conformation and biological ac-tivity of Bloom helicase ( BLM ) , and to explore its antitumor mechanism.Methods The effect of HL-49 on the conformation of BLM helicase was studied by ultra- violet spectroscopy.The effects of HL-49 on DNA binding activity, DNA chain dissociation activity and ATPase activity of HL-49 on BLM DNA helicase were analyzed by fluorescence polarization and malachite green-ammonium phosphomolybdate colorimetric method.Results HL-49, a tetrandrine derivative, indirectly inhibited the ATPase activity of BLM DNA heli- case and DNA unwinding activity by reversible binding with DNA.The results of fluorescence polarization experiments showed that HL-49 could not affect the bind ing activity of BLM DNA helicase to DNA (dsDNA/ss- DNA) , but could bind to DNA in a concentration-de- pendent manner (P < 0.01).With the increase of HL- 49 concentration, the DNA unwinding ability of BLM DNA helicase decreased, and the Kobs value decreased gradually.The results of malachite green-ammonium phosphomolybdate colorimetry showed that HL-49 could significantly inhibit the ATPase activity of BLM DNA helicase.Conclusions HL49 can inhibit the ATPase activity and DNA unwinding activity of BLM DNA helicase by the reversible binding with DNA.
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Aim To investigate the effects of bisbenzyl-isoquinoline alkaloid tetrandrine derivative HL-27 on the biological properties of the BLM642-1290 helicase. Methods Fluorescence polarization technique was used to investigate the effects of bisbenzylisoquinoline alkaloid tetrandrine derivative HL-27 on the DNA bind-ing activity and unwinding activity of the BLM642-1290 helicase. Malachite green-phosphate ammonium molyb-date colorimetry was used to investigate the effects of HL-27 on the ATPase activity of the BLM642-1290 heli-case. Ultraviolet spectral scanning was used to investi-gate the effects of HL-27 on the conformation of the BLM642-1290 helicase. Results When the concentra-tion of HL-27 reached 33.34 μmol·L-1, the inhibi-tion ratio of dsDNA and ssDNA binding activity of the BLM642-1290 helicase was 41.35% and 59.54% , re-spectively. When the concentration of HL-27 reached 50 μmol·L-1, the inhibition ratio of DNA unwinding activity of the BLM642-1290 helicase was 78.68% . When the concentration of HL-27 reached 100 μmol· L-1, the inhibition ratio of ATPase activity of the BLM642-1290 helicase was 43.8% . Conclusion The DNA binding activity, ATPase activity and unwinding activity of the BLM642-1290 helicase can be inhibited by bisbenzylisoquinoline alkaloid tetrandrine derivative HL-27.
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Objective To explore the clinical and imaging features of Hallervorden-Spatz syndrome (HSS) and its deep brain stimulation (DBS) treatment.Methods A 12-year-old boy with HSS,admitted to our hospital from June 2010,was chosen in our study; the clinical and imaging features and the DBS therapy outcome were retrospectively analyzed.Results The patient (12 years old) was at an early onset,predominantly presented with dystonia,cognitive impairment,dysarthria and pyramidal signs; the symptoms were rapidly progressive.Brain MRI revealed a typical "eye-of-tiger" sign.Significant improvement of motor function after DBS of the internal globus pallidus (Gpi) and no significant improvement of cognitive dysfunction and dysarthria were noted; and the benefit of surgery was maintained during the 1 year follow-up.Conclusion The characteristic imaging manifestations and clinical features are very important for HSS diagnosis; DBS of the internal globus pallidus (Gpi) can improve the motor function; and DBS is one of the limited optional therapies for HSS.
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Objective To investigate the probability of quantitative analysis of parkinsonian gaits in unilateral 6-hydroxyl dopamine-lesioned rats. Methods A total of 24 male Wistar rats were assigned to control group (n=6),sham-operated group (n=6) and 6-OHDA inducement group (n=12).All subjects received anesthetization and the latter 2 groups further processed with injection of equivalent volumes of normal saline and 6-OHDA into the left medial longitudinal fasciculus on the operation day,respectively. The cylinder test and Catwalk analysis were applied successively 1 week before the operation for baseline value,and 3 d, 1 and 2 weeks after the operation. Results The cylinder test indicated that the proportion of using the right forelimbs was significantly decreased as compared with that using the left forelimbs in the 6-OHDA inducement group 3 d, 1 and 2 weeks after the operation (P＜0.05), but no significant differences of using the right forelimbs were shown in the control and sham-operated counterpart (P＞0.05). Catwalk analysis showed no significant differences either on the girdle comparisons of former/hinder limbs or on pre- and post-operation comparisons of individual limbs between control and sham-operated groups (P＞0.05). In the 6-OHDA inducement group,max contact area (MCA),paw length (PL),paw width (PW) and paw area (PA) for fore girdle comparisons and MCA for hinder ones showed significant differences (P＜0.05); all the 4 parameters of right hinder limb,the PL,PW and PA of left fore limb,the PA,PL and MCA of right fore limb,the PW of left hinder limb after the operation significantly decreased as compared with those before the operation (P＜0.05). Conclusion It is applicable to detect changes in gaits of Parkinson's disease quantitatively with Catwalk analysis,especially in terms of MCA,adding new tool for further study.
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Objective To introduce a bundled microelectrode array of chronic in vivo single-unit recording in subthalamie nucleus (STN) of freely behaving rats. Methods STN single cell discharge was recorded by a self-designed bundled microelectrode array.Our microelectrode array design consisted of 3 parts:(1) a 29-guage stainless steel tube was served as a guide tube to facilitate the brain penetration of microwire tips,and as a ground electrode of the brain tissues as well. (2) Five 20μm platiniridium wires were used as recording electrodes and a 50.8 μm stainless steel wire with 1 mm bare tip was employed as local potential reference; all the above resembled a guiding-hand-shaped arrangement in microwire tips,and was fixed by trny plot of carbowax moreover.(3) A male connector with end screw receptors was employed to make the array connection more stable so as to minimize the movement artifacts; six normal rats were implanted with this kind of electrode arrays,and the stability of STN single-unit recording was evaluated in the following 5 weeks. Results Twenty-seven firing units were captured during operation,of which 70.4％ (19/27) survived more than 2 d,and 9 new units were acquired within 5 weeks.No significant linear correlation of peak-to-peak amplitude was noted between each 2 different recording sections (Pearson r=-0.047,P=0.655),and whilst signal-to-noise ratio was stable with significant correlation to peak-to-peak amplitude (r=0.934,P=0.000).More than half of the initial acquired STN units retained more than 3 weeks. And there were more than 75％ r values of waveform similarities large than 0.90 of the same units across different periods. Conclusion This methodology may be appreciated for STN long-term single-unit recording with stable recording quality and favorable cell retained rate.
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Mesenchymal stem cells are capable of differentiating into Schwann-like cells. In this study, we induced human umbilical-cord mesenchymal stem cells (HUMSCs) in vitro into neurospheres constituted by neural stem-like cells, and further into cells bearing strong morphological, phenotypic and functional resemblances with Schwann-like cells. These HUMSC-derived Schwann-like cells, after grafting into the injured area of the rats' spinal cord injury (SCI), showed a partial therapeutic effect in terms of improving the motor function. Neurotrophin-3 (NT-3) was reported to improve the local microenvironment of the grafted cells, and we, therefore, further tested the effect of Schwann-like cell grafting combined with NT-3 administration at the site of cell transplantation. The results showed that NT-3 administration significantly promoted the survival of the grafted cells in the host-injured area. Significant improvement in rats treated by Schwann-like cell grafting combined with NT-3 administration was demonstrated in the behavioral test as compared with that in animal models received the cell grafting only. These results suggest that transplantation of the Schwann-like cells combined with NT-3 administration may represent a new strategy of stem cell therapy for spinal cord injury.