Conjugated polymer nanoparticles for effective siRNA delivery to tobacco BY-2 protoplasts

<p>Abstract</p> <p>Background</p> <p>Post transcriptional gene silencing (PTGS) is a mechanism harnessed by plant biologists to knock down gene expression. siRNAs contribute to PTGS that are synthesized from mRNAs or viral RNAs and function to guide cellular endoribonucleases to target mRNAs for degradation. Plant biologists have employed electroporation to deliver artificial siRNAs to plant protoplasts to study gene expression mechanisms at the single cell level. One drawback of electroporation is the extensive loss of viable protoplasts that occurs as a result of the transfection technology.</p> <p>Results</p> <p>We employed fluorescent conjugated polymer nanoparticles (CPNs) to deliver siRNAs and knockdown a target gene in plant protoplasts. CPNs are non toxic to protoplasts, having little impact on viability over a 72 h period. Microscopy and flow cytometry reveal that CPNs can penetrate protoplasts within 2 h of delivery. Cellular uptake of CPNs/siRNA complexes were easily monitored using epifluorescence microscopy. We also demonstrate that CPNs can deliver siRNAs targeting specific genes in the cellulose biosynthesis pathway (<it>NtCesA-1a </it>and <it>NtCesA-1b)</it>.</p> <p>Conclusions</p> <p>While prior work showed that <it>NtCesA-1 </it>is a factor involved in cell wall synthesis in whole plants, we demonstrate that the same gene plays an essential role in cell wall regeneration in isolated protoplasts. Cell wall biosynthesis is central to cell elongation, plant growth and development. The experiments presented here shows that <it>NtCesA </it>is also a factor in cell viability. We show that CPNs are valuable vehicles for delivering siRNAs to plant protoplasts to study vital cellular pathways at the single cell level.</p

Comparison of Surgical Outcomes in Thoracolumbar Fractures Operated with Posterior Constructs Having Varying Fixation Length with Selective Anterior Fusion

PURPOSE: Surgical treatment in the case of thoracolumbar burst fractures is very controversial. Posterior instrumentation is most frequently used, however, but the number of levels to be instrumented still remains a matter of debate. MATERIALS AND METHODS: A total of 94 patients who had a single burst fracture between T11 and L2 were selected and were managed using posterior instrumentation with anterior fusion when necessary. They were divided into three groups as follows; Group I (n = 28) included patients who were operated by intermediate segment fixation, Group II (n = 32) included patients operated by long segment fixation, and Group III (n = 34) included those operated by intermediate segment fixation with a pair of additional screws in the fractured vertebra. The mean follow-up period was twenty one months. The outcomes were analyzed in terms of kyphosis angle (KA), regional kyphosis angle (RA), sagittal index (SI), anterior height compression rate, Frankel classification, and Oswestry Disability Index questionnaire. RESULTS: In Groups II and III, the correction values of KA, RA, and SI were much better than in Group I. At the final follow up, the correction values of KA (6.3 and 12.1, respectively) and SI (6.2 and 12.0, respectively) were in Groups II and III found to be better in the latter. CONCLUSION: The intermediate segment fixation with an additional pair of screws at the fracture level vertebra gives results that are comparable or even better than long segment fixation and gives an advantage of preserving an extra mobile segment.ope

Decreased DBC1 Expression Is Associated With Poor Prognosis in Patients With Non-Muscle-Invasive Bladder Cancer

Purpose The deleted in bladder cancer 1 (DBC1) gene is located within chromosome 9 (9q32-33), a chromosomal region that frequently shows loss of heterozygosity in bladder cancer (BC). It is suspected that it acts as a tumor suppressor gene, but its prognostic value remains unclear. The aim of the present study was to investigate the value of DBC1 as a prognostic marker in BC. Materials and Methods The expression of DBC1 was determined by real-time polymerase chain reaction analysis in 344 patients with BC (220 non-muscle-invasive BC [NMIBC] and 124 muscle-invasive BC [MIBC]) and in 34 patients with normal bladder mucosa. The results were compared with clinicopathologic parameters, and the prognostic value of DBC1 was evaluated by Kaplan-Meier analysis and a multivariate Cox regression model. Results: DBC1 expression was significantly decreased in patients with MIBC compared with those diagnosed with NMIBC (p=0.010). Patients with aggressive tumor characteristics had lower DBC1 expression levels in NMIBC (each, p<0.05). By multivariate Cox regression analysis, low DBC1 expression was a predictor of progression to MIBC (hazard ratio, 7.104; p=0.013). Kaplan-Meier estimates revealed a significant difference in tumor recurrence, progression to MIBC, and cancer-specific survival depending on the level of DBC1 expression in NMIBC (log-rank test, each, p<0.05). Conclusions: The expression of DBC1 was associated with tumor aggressiveness, progression to MIBC, and survival in NMIBC. Our results suggest that DBC1 expression can be a useful prognostic marker for patients with NMIBC

Change in Effective Leg Length after Angular Deformity Correction by Hemiepiphyseal Stapling

Background: The hemiepiphyseal stapling has both positive and negative effects on effective leg length. The purpose of this study was to analyze change in effective leg length after angular correction by hemiepiphyseal stapling, and to validate in clinical cases. Methods: Mathematical analysis of a hemiepiphyseal stapling model was conducted. The induced formula was validated in 6 cases fulfilling the assumptions of the model. Anatomical parameters involved in this formula were measured in additional 21 cases undergoing hemiepiphyseal stapling or hemiepiphysiodesis. Results: Effective leg length increased or decreased according to three parameters in this model: 1) limb length distal to the operated physis (L), 2) width of the operated physis (d), and 3) the amount of angular deformity to be corrected (&amp;theta;). Actual change in effective leg length of 6 cases similar to this model coincided with the predicted change at least in its direction. L/d ratio was 4.82 ± 0.51. Conclusions: Considering the narrow range of the L/d ratio, hemiepiphyseal stapling is likely to decrease effective leg length if the amount of angular correction is less than 10°, whereas to increase it if the amount of angular correction is larger than 16°. This should be taken into consideration when selecting the surgical method for angular deformity correction in skeletally immature patients. © 2010 by The Korean Orthopaedic Association.Y

Pulsed Electromagnetic Field Stimulates Cellular Proliferation in Human Intervertebral Disc Cells

∙The authors have no financial conflicts of interest. Purpose: The purpose of this study is to investigate the mechanism of cellular proliferation of electromagnetic field (EMF) on human intervertebral disc (IVD) cells. Materials and Methods: Human IVD cells were cultured three-dimensionally in alginate beads. EMF was exposed to IVD cells with 650 Ϊ, 1.8 millitesla magnetic flux density, 60 Hz sinusoidal wave. Cultures were divided into a control and EMF group. Cytotoxicity, DNA synthesis and proteoglycan synthesis were measured by MTT assay, [ 3 H]-thymidine, and [ 35 S]-sulfate incorporation. To detect phenotypical expression, reverse transcription-polymerase chain reactions (RT-PCR) were performed for aggrecan, collagen type I, and type II mRNA expression. To assess action mechanism of EMF, IVD cells were exposed to EMF with N G-Monomethyl-L-arginine (NMMA) and acetylsalicylic acid (ASA). Results: There was no cytotoxicity in IVD cells with the EMF group in MTT assay. Cellular proliferation was observed in the EMF group (p &lt; 0.05). There was no difference in newl

Cytotoxicity of gamma-ray in rat immature hippocampal neurons

This in vitro study evaluated the detrimental effect of acute gamma (γ)-irradiation on rat immature hippocampal neurons. Rat immature hippocampal neurons (0.5 day in vitro) were irradiated with 0~4 Gy γ-rays. Cytotoxicity was analyzed using a lactate dehydrogenase release assay at 24 h after γ-irradiation. Radiation-induced cytotoxicity in immature hippocampal neurons increased in a dose-dependent manner. Pre-treatments of pro-apoptotic caspase inhibitors and anti-oxidative substances significantly blocked γ-irradiation-induced cytotoxicity in immature hippocampal neurons. The results suggest that the caspase-dependent cytotoxicity of γ-rays in immature hippocampal cultured neurons may be caused by oxidative stress

Laparoscopy-assisted distal gastrectomy for gastric cancer after liver transplantation

A case report described a 72-year-old man with a history of a deceased-donor liver transplantation (due to hepatitis B-associated end-stage liver cirrhosis) performed in 1994. The patient was diagnosed with renal cell carcinoma and pulmonary metastasis in 1997 and was successfully treated with radiofrequency ablation and thoracoscopic superior segmentectomy. There was no evidence of newly diagnosed metastatic lesions or recurrence until the 19th post-operative month. Gastric cancer was identified by endoscopy during a routine follow-up examination; the pre-pyloric antral lesion measured 1.5 cm in size and was histologically well-differentiated and confined to the submucosal layers on endoscopic ultrasound. Laparoscopic gastrectomy and lymph node dissection (D1 + β) was successfully performed in March 2009, and the patient was discharged on the 5th post-operative day without complications. This suggests that laparoscopic surgery is one of the feasible methods for resection of gastric cancer in liver transplant patients