Dicer-substrate siRNA inhibits tumor necrosis factor alpha secretion in Kupffer cells in vitro: in vivo targeting of Kupffer cells by siRNA-liposomes.

Tumor necrosis factor alpha (TNF-α) plays a major role in the pathogenesis of many inflammatory diseases. Neutralizing TNF-α by antibodies or antisense oligodeoxynucleotides, alleviate disease symptoms. In this study, we introduce the new generation of gene-silencing molecules, namely the small interfering RNAs (siRNAs) to reduce TNF-α. Although siRNAs of 19-21bp are commonly used, it is reported that longer siRNAs have much higher efficacies. Here, we report the identification of a 27-mer Dicer-substrate siRNA (DsiRNA) against TNF-α mRNA. Primary cells of rat Kupffer cells were transfected with five 27-mer siRNA constructs (si27-1, si27-2 si27-3, si27-4 and si27-5) for 24h, following which, TNF-α secretion was induced by exposure to LPS (0.1µg/ml) for 2h. TNF-α released to the medium was measured by ELISA. Of the five si27 constructs, si27-3 had the highest inhibitory effect on TNF-α secretion. At 10nM, si27-3 inhibited TNF-α secretion by 80% compared to a 60% inhibition by a 21-mer (SSL3). Following encapsulation in anionic liposomes, si27-3 at 100µg/kg body weight, on two successive days by intravenous administration, inhibited the secretion of TNF-α by 50%. These data demonstrate the identification of a highly efficacious siRNA formulation, which can be used in the treatment of TNF-α mediated diseases.

Community succession and functional prediction of microbial consortium with straw degradation during subculture at low temperature.

To systematically explore and analyze the microbial composition and function of microbial consortium M44 with straw degradation in the process of subculture at low temperature. In this study, straw degradation characteristics of samples in different culture stages were determined. MiSeq high-throughput sequencing technology was used to analyze the evolution of community structure and its relationship with degradation characteristics of microbial consortium in different culture periods, and the PICRUSt function prediction analysis was performed. The results showed that straw degradation rate, endoglucanase activity, and filter paper enzyme activity of M44 generally decreased with increasing culture algebra. The activities of xylanase, laccase, and lignin peroxidase, as well as VFA content, showing a single-peak curve change with first an increase and then decrease. In the process of subculture, Proteobacteria, Bacteroidetes, and Firmicutes were dominant in different culture stages. Pseudomonas, Flavobacterium, Devosia, Brevundimonas, Trichococcus, Acinetobacter, Dysgonomonas, and Rhizobium were functional bacteria in different culture stages. It was found by PICRUSt function prediction that the functions were concentrated in amino acid transport and metabolism, carbohydrate transship and metabolism related genes, which may contain a large number of fibers and lignin degrading enzyme genes. In this study, the microbial community succession and the gene function in different culture periods were clarified and provide a theoretical basis for screening and rational utilization of microbial consortia.

Moderate sedation by total intravenous remimazolam-alfentanil vs. propofol-alfentanil for third molar extraction: A prospective randomized controlled trial.

Background: Oral dental treatment cause anxiety, fear, and physical stress. This study aimed to investigate the efficacy and safety of moderate sedation by remimazolam with alfentanil vs. propofol with alfentanil in third molar extraction. Methods: This single-center, randomized, single-blind clinical trial included 100 adults who underwent third molar ambulatory extraction. All patients had continuous infusion of Alfentanil 0.2 µg/kg/min. Group remimazolam with alfentanil (group RA) had an induction dose of 80 µg/kg and maintenance dosage of 5 µg/kg/min. In group propofol with alfentanil (PA group), propofol was infused at an initial concentration of 1.8 µg/mL under target controlled infusion (TCI) mode and a maintenance concentration of 1.5 µg/mL. The incidence rates of adverse effects were recorded and compared. Depth of sedation was assessed using the modified observer alertness/sedation assessment (MOAA/S) and entropy index. Recovery characteristics were recorded and complications observed for next 24 h. Results: The incident of adverse events 6 (12%) in the group RA was lower than the group PA 25 (50%) [Mean difference 0.136 (95%CI, 0.049-0.377); P < 0.05], with no serious adverse events during the sedation procedure. The incidence of injection pain in group RA was significantly lower than that in group PA [4 vs. 26%, mean difference 0.119 (95%CI, 0.025-0.558); P = 0.004]. Before starting local anesthesia, the mean arterial pressure, heart rate, and respiratory rate of the PA group were lower than those of the RA group. None of the patients required further treatments for a decreased heart rate, blood pressure, or low SpO2. The rate of moderate sedation success was 100% in both groups. The MOAA/S score was similar between the groups indicating that the depth of sedation was effective. Group RA had significantly shorter recovery and discharge times than those of group PA. Conclusions: Remimazolam with alfentanil is a safer and more effective alternative for ambulatory sedation and can reduce recovery and discharge time and the incidence of perioperative adverse events compare with propofol. Clinical trial registration: http://www.chictr.org.cn/index.aspx, identifier: ChiCTR2200058106.

[Palatal fistula rate after Huaxi Sommerlad-Furlow palatoplasty].

OBJECTIVE: This study aimed to determine the palatal fistula rate, explore the influencing factors of Huaxi Sommerlad-Furlow (SF) palatoplasty. METHODS: A retrospective review of 385 consecutive cleft-palate cases was performed to determine the incidence of postoperative fistula and assess the possible contributing factors, such as sex, weight, age, cleft type, operator skills, preoperative white blood cell, preventive antibiotic use, and postoperative temperature. RESULTS: Fistulas occurred in 15/385 patients (3.9%). Among them, 1 fistula was located at the junction of the hard and soft palates, 12 fistulas in hard palate, and 2 fistulas in alveolar near the hard palate. No evidence suggested that sex, weight, age, preoperative white blood cell, preventive antibiotic use, and postoperative temperature are associated with fistula formation. The incidences of cleft palate fistulas as encountered by senior professors (3.03%) and associate senior professors (2.23%) were significantly lower than those by attending doctors (14.29%, P<0.05). The incidences of cleft palate fistulas in bilateral completely cleft palate cases (20.6%) were significantly higher than those in hard and soft (3.6%) and unilateral cleft palate cases (2.6%, P<0.05). CONCLUSIONS: Huaxi SF palatoplasty can avoid the inhibited maxillary growth without requiring lateral relaxing incision, which poses an acceptable risk of fistula formation. The palatal fistula rate is not related to the sex, weight, age of operation, prophylactic use of antibiotics before operation, infection before operation, temperature after operation and other factors. The occurrence of the fistula is related mainly to cleft type and experience level of the surgeon.

Changes of masseter muscles after mandibular angle ostectomy in rhesus monkeys.

Mandibular angle ostectomy is a common procedure for the correction of a prominent mandibular angle in Asia. However, the alterations of masseter muscles following resection of the mandibular angle are not well known. In this study, 12 adult rhesus monkeys were used to investigate the effects of mandibular angle ostectomy on the masseter muscle. Mandibular angle ostectomy was performed on one side of the mandible and the other side remained intact and was used as normal control. Four animals were randomly killed at 12, 24, and 48 weeks postoperatively, respectively. The morphologic, histologic, and electromyographic examinations were used to compare the differences of masseter muscle between the ostectomized and normal sides. On the ostectomized side the electromyographic activity, cross sectional area, mass, thickness, and length of the masseter muscle were all decreased, despite a trend to recover with time. Histologic examination showed that the muscular reattachment on the ostectomized side resembled normal muscle attachment eventually. The results showed that secondary atrophic changes would occur in the masseter muscle after mandibular angle resection. This study may be helpful for predicting the final cosmetic outcomes of mandibular angle ostectomy.

Simple 3,4-Dihydroxy-L-Phenylalanine Surface Modification Enhances Titanium Implant Osseointegration in Ovariectomized Rats.

Osteoporosis presents a challenge to the long-term success of osseointegration of endosseous implants. The bio-inspired 3,4-dihydroxy-L-phenylalanine (Dopa) coating is widely used as a basic layer to bind osteogenetic molecules that may improve osseointegration. To date, little attention has focused on application of Dopa alone or binding inhibitors of bone resorption in osteoporosis. Local use of a bisphosphonate such as zoledronic acid (ZA), an inhibitor of osteoclast-mediated bone resorption, has been proven to improve implant osseointegration. In this study, ovariectomized rats were divided into four groups and implanted with implants with different surface modifications: sandblasted and acid-etched (SLA), SLA modified with Dopa (SLA-Dopa), SLA modified with ZA (SLA-ZA), and SLA modified with Dopa and ZA (SLA-Dopa + ZA). Measurement of removal torque, micro-computed tomography and histology revealed a greater extent of bone formation around the three surface-modified implants than SLA-controls. No synergistic effect was observed for combined Dopa + ZA coating. Microarray analysis showed the Dopa coating inhibited expression of genes associated with osteoclast differentiation, similarly to the mechanism of action of ZA. Simple Dopa modification resulted in a similar improvement in osseointegration compared to ZA. Thus, our data suggest simple Dopa coating is promising strategy to promote osseointegration of implants in patients with osteoporosis.

Recurrent ameloblastoma of the anterior skull base: three cases treated by radical resections.

INTRODUCTION: Recurrent ameloblastomas rarely present in the anterior skull base but are, common following inadequate excision. PATIENTS AND METHODS: Three patients are presented with ameloblastoma in the anterior skull base including frontotemporal fossa and pterygomaxillary fossa recurring following multiple enucleations, segmental mandibulectomy, or partial maxillectomy. The recurrences were found 3-4 years following the primary operations. All 3 patients were treated by radical dissection. RESULTS: Microscopically one case was a mixed follicular and plexiform, two cases were of a follicular type. All patients healed without serious complications. CONCLUSION: Ameloblastomas in these regions have a greater recurrence potential even when treated by radical dissection.

Chemosensitization and radiosensitization of a lung cancer cell line A549 induced by a composite polymer micelle.

Multidrug resistance (MDR) to Doxorubicin (DOX) remains a major obstacle to successful cancer treatment. The present study sought to overcome the MDR of lung cancer cells and achieve radiosensitization by developing a composite DOX-loaded micelle (M-DOX). M-DOX containing PEG-PCL/Pluronic P105 was prepared by the solvent evaporation method. Lung cancer cell line A549 was adopted in this study. In vitro cytotoxicity, cellular uptake behavior, subcellular distribution, and radiosensitivity were evaluated by the treatment with M-DOX, and free DOX was used as a control. A549 cells treated with M-DOX as opposed to free DOX showed greater cellular uptake as well as greater cytotoxicity. Furthermore, M-DOX reached the mitochondria and lysosome effectively after cellular uptake, and fluorescence used to track M-DOX was found to be surrounding the nucleus. Finally, colony-forming assays demonstrated that M-DOX treatment improved radiosensitization when compared to free DOX. Based on the increased cytotoxicity and radiosensitization, M-DOX could be considered as a promising drug delivery system to overcome MDR in lung cancer therapy.

Lymphatic networks in the periodontal tissue and dental pulp as revealed by histochemical study.

The structural organization and fine distribution of the lymphatic networks in the periodontal tissues (gingiva, periodontal membrane, and alveolar process) and dental pulp of animals and humans were reviewed with special reference to histochemical examination by light and electron microscopy. The distinction between lymphatics and blood vessels was made on cryostat sections of undecalcified and calcified teeth treated with EDTA solution and whole mount preparations of periodontal membranes using 5'-nucleotidase (5'-Nase)-alkaline phosphatase (ALPase) double staining. This staining procedure allowed lymphatic vessels in the periodontal tissue and dental pulp to be differentiated from blood vessels. The specificity and localization of the enzyme reactions were confirmed by comparative histochemical studies of the same specimen with light microscopy and scanning or transmission electron microscopy. Well-developed 5'-Nase-positive lymphatic networks were observed on the tissue sections and whole mount preparations of the gingiva, periodontium, and dental pulp. More lymphatic vessels were seen in the root area of the periodontium than in the cervical area. In the dental pulp, lymphatic vessels were more numerous in the central part than in the peripheral odontoblastic layer. These distributions of the lymphatic capillary networks are discussed in relation to their ability to supply lymph to the teeth.

Ectopic osteoid and bone formation by three calcium-phosphate ceramics in rats, rabbits and dogs.

Calcium phosphate ceramics with specific physicochemical properties have been shown to induce de novo bone formation upon ectopic implantation in a number of animal models. In this study we explored the influence of physicochemical properties as well as the animal species on material-induced ectopic bone formation. Three bioceramics were used for the study: phase-pure hydroxyapatite (HA) sintered at 1200°C and two biphasic calcium phosphate (BCP) ceramics, consisting of 60 wt.% HA and 40 wt.% TCP (ß-Tricalcium phosphate), sintered at either 1100°C or 1200°C. 108 samples of each ceramic were intramuscularly implanted in dogs, rabbits, and rats for 6, 12, and 24 weeks respectively. Histological and histomorphometrical analyses illustrated that ectopic bone and/or osteoid tissue formation was most pronounced in BCP sintered at 1100°C and most limited in HA, independent of the animal model. Concerning the effect of animal species, ectopic bone formation reproducibly occurred in dogs, while in rabbits and rats, new tissue formation was mainly limited to osteoid. The results of this study confirmed that the incidence and the extent of material-induced bone formation are related to both the physicochemical properties of calcium phosphate ceramics and the animal model.

Combined effects of connective tissue growth factor-modified bone marrow-derived mesenchymal stem cells and NaOH-treated PLGA scaffolds on the repair of articular cartilage defect in rabbits.

In cartilage tissue engineering using stem cells, it is important to stimulate proliferation and control the differentiation of stem cells to specific lineages. Here we reported a combined technique for articular cartilage repair, consisting of bone marrow mesenchymal stem cells (BMMSCs) transfected with connective tissue growth factor (CTGF) gene and NaOH-treated poly(lactic-co-glycolic) acid (PLGA) scaffolds. In the present study, BMMSCs or CTGF-modified BMMSCs seeded on PLGA or NaOH-treated PLGA scaffolds were incubated in vitro and NaOH-treated PLGA significantly stimulated proliferation of BMMSCs, while CTGF gene transfer promoted chondrogenic differentiation. The effects of the composite on the repair of cartilage defects were evaluated in rabbit knee joints in vivo. Full-thickness cartilage defects (diameter: 5 mm; depth: 3 mm) were created unilaterally in the patellar groove. Defects were either left empty (n = 18) or implanted with BMMSCs/PLGA (n = 18), BMMSCs/NaOH-treated PLGA (n = 18), or CTGF-modified BMMSCs/NaOH-treated PLGA (n = 18). The defect area was examined grossly, histologically, and mechanically at 6, 12, and 24 weeks postoperatively. Implanted cells were tracked using adeno-LacZ labeling at 6 weeks after implantation. Overall, the CTGF-modified BMMSCs/NaOH-treated PLGA group showed successful hyaline-like cartilage regeneration similar to normal cartilage, which was superior to the other groups using gross examination, qualitative and quantitative histology, and mechanical assessment. The in vivo viability of the implanted cells was demonstrated by their retention for 6 weeks after implantation. These findings suggested that a combination of CTGF-modified BMMSCs and NaOH-treated PLGA may be an alternative treatment for large osteochondral defects in high-loading sites.

Effect of different doses of transforming growth factor-ß1 on cartilage and subchondral bone in osteoarthritic temporomandibular joints.

Transforming growth factor-beta (TGF-ß) plays an important part in the repair of cartilage in osteoarthritis. It has been hypothesised that intra-articular injection of TGF-ß1 promotes repair of cartilage and protects the subchondral bone from damage in osteoarthritic temporomandibular joints (TMJs). We made bilateral partial perforations of the disc to induce osteoarthritic joints in 36 rabbits. TGF-ß1 20, 40, or 80 ng were injected into the right joint, and vehicle alone was injected into the left joint. Four additional animals were used as normal controls. Microcomputed tomography was used to quantify the three-dimensional microarchitecture of subchondral bone, followed by assessment of the proteoglycan content. All joints treated with TGF-ß1 were covered by a layer of well-organised fibrocartilage, and had increased proteoglycan content and normal microarchitectural properties, whereas the joint treated by vehicle alone had typical osteoarthritis-related degradation of cartilage and sclerosis of subchondral bone. These results suggested that TGF-ß1 is an effective way of treating osteoarthritis of the TMJ.

The epidemiology of cranio-facial injuries caused by animals in southern-central China.

A clinical investigation was conducted to demonstrate the epidemiology of cranio-facial injuries inflicted by animals in southern-central part of China-the World's most populous eastern country. It consisted of a retrospective study of 149 patients and was carried out in our department. All the patients were attacked by animals, such as buffalo, cattle, donkey, horse, dog, cat, and rat. There were 91 males and 58 females patients, aged from 5 to 65 years. 113 patients were from rural areas, and 36 from urban districts. Dogs, cattle, donkeys and buffalo, were the most common animals involved in this study. Bite was the predominant mechanism of injury, followed by kick, fall, trample, knock and scratch. The lip, chin and cheek were the commonest sites of soft tissue injury; Condylar process, symphysis, parasymphysis, and angle of mandible were the sites of fractures. Regarding the severity of injury, nearly half of the patients belonged to I and II classifications. The treatment results were satisfactory except for obvious scar formation, facial nerve palsy, and dysocclusion in a few patients. Facial injuries caused by animals are common in China, especially in rural areas. Timely treatment should be performed as soon as possible. Special attention should be paid to the prescription of antibiotics and vaccines. Psychotherapy may also be considered when necessary. It is suggested that adequate protective measures should be taken when animals are used for agricultural activities or kept as pets to minimize the incidence of facial injury.

[Clinical characteristics of bronchiolitis obliterans in pediatric patients].

OBJECTIVE: To analyze the clinical characteristics, image findings, laboratory examination, the therapeutic methods and clinical outcomes of bronchiolitis obliterans (BO) in pediatric patients. METHOD: Twenty-six pediatric patients with BO were reported. All data were collected from cases who were hospitalized in the Department of Pediatrics, First Affiliated Hospital of Guangzhou Medical College from June 1(st), 2009 to the April 30(th), 2011, and infectious agents, clinical manifestations, risk factors, changes in imageology, laboratory examination, therapeutic methods and treatment responses were analyzed. RESULT: The ranges of age at onset was 4.5 months-8 years in 26 cases (18 boys and 8 girls). The course of disease was (6.2 ± 3.5) months. The period of followed-up ranged from 2 to 24 months. The common clinical characteristics were persistent wheezing of different severity (26 cases, 100%), cough (24 cases, 92%), intolerance to exercise (22 cases, 85%), short of breath (21 cases, 81%), retraction (20 cases, 77%), wheezy phlegm (16 cases, 62%), keeping with crackles (10 cases, 38%), cyanosis around the mouth (3 cases, 12%) and no clubbed fingers (toes). In 18 cases the etiology was detected, mycoplasma (11 cases, 42%), respiratory syncytial virus (4 cases, 15%), parainfluenza virus (2 cases, 8%), influenza virus A (2 cases, 8%) and influenza virus B (2 cases, 8%), human bocavirus (HBoV) (1 case, 4%). There were 8 cases (31%) with combined infection. Chest X-ray in 10 cases indicated changes suggestive of bronchopneumonia (38%), in only 1 case there was an image of interstitial pneumonia disease (4%). All the patients were diagnosed by high-resolution computerized tomography (HRCT). All cases were demonstrated to have air retention, poor blood perfusion in lung, just like "Westemark sign" with HRCT. In 19 cases antineutrophil cytoplasmic antibody (ANCA) was determined and 10 patients (53%) were positive for P-ANCA, and 8 cases (42%) were positive for C-ANCA. All patients received oral corticosteroid and low doses azithromycin. In 13 cases (50%) the treatment effectively reduced the severity of disease and the frequency of cough and wheezing. The average number of days for symptom improvement was (7.1 ± 4.8) days. CONCLUSION: Respiratory infection plays an important role in BO in children. The chronic and persistent wheezing, cough, intolerance to exercises, short breath, retraction were the main clinical manifestations. But these symptoms are non-specific. Chest X-ray can not provide enough information for diagnosis. Classical "Westemark sign" with HRCT is an important sign. ANCA with a high positive rate (approximately 50%) suppose immuno-lesion in BO. Oral corticosteroid and methotrexate may relieve clinical symptoms.

Oval cell response is attenuated by depletion of liver resident macrophages in the 2-AAF/partial hepatectomy rat.

BACKGROUND/AIMS: Macrophages are known to play an important role in hepatocyte mediated liver regeneration by secreting inflammatory mediators. However, there is little information available on the role of resident macrophages in oval cell mediated liver regeneration. In the present study we aimed to investigate the role of macrophages in oval cell expansion induced by 2-acetylaminofluorene/partial hepatectomy (2-AAF/PH) in rats. METHODOLOGY/PRINCIPAL FINDINGS: We depleted macrophages in the liver of 2-AAF/PH treated rats by injecting liposome encapsulated clodronate 48 hours before PH. Regeneration of remnant liver mass, as well as proliferation and differentiation of oval cells were measured. We found that macrophage-depleted rats suffered higher mortality and liver transaminase levels. We also showed that depletion of macrophages yielded a significant decrease of EPCAM and PCK positive oval cells in immunohistochemical stained liver sections 9 days after PH. Meanwhile, oval cell differentiation was also attenuated as a result of macrophage depletion, as large foci of small basophilic hepatocytes were observed by day 9 following hepatectomy in control rats whereas they were almost absent in macrophage depleted rats. Accordingly, real-time polymerase chain reaction analysis showed lower expression of albumin mRNA in macrophage depleted livers. Then we assessed whether macrophage depletion may affect hepatic production of stimulating cytokines for liver regeneration. We showed that macrophage-depletion significantly inhibited hepatic expression of tumor necrosis factor-α and interleukin-6, along with a lack of signal transducer and activator of transcription 3 phosphorylation during the early period following hepatectomy. CONCLUSIONS: These data indicate that macrophages play an important role in oval cell mediated liver regeneration in the 2-AAF/PH model.

Protection of articular cartilage from degeneration by injection of transforming growth factor-beta in temporomandibular joint osteoarthritis.

OBJECTIVE: This study aimed to examine the effect of injection of transforming growth factor beta (TGF-beta) on articular cartilage in osteoarthritic temporomandibular joint (TMJ). STUDY DESIGN: Disc perforation was performed bilaterally in 24 rabbits to induce osteoarthritis (OA). The right joint was injected with TGF-beta as experimental groups, and the left joint with physiologic saline as control. Animals were killed at different intervals. Histology and reverse transcriptase polymerase chain reaction was performed for comparison. RESULTS: All joints showed OA-like changes, but the degree in the experimental was significantly less severe than in the control. At 12 weeks a significantly greater expression of aggrecan and collagen type II was found in the experimental compared with the control joints. However, no difference in either anabolic or catabolic genes was found between the two groups at 24 weeks. CONCLUSIONS: Transforming growth factor beta may have a potential benefit in protecting articular cartilage during the development of TMJ OA.

[Donor site choice for free flaps in head and neck reconstruction after tumor surgery].

OBJECTIVE: To choose suitable free flaps for reconstructing head and neck defects caused by tumor resection. METHODS: A retrospective analyses was made in 86 cases of head and neck defects treated with four kinds of free flaps between January 1999 and January 2002. The head and neck defects were caused by tumor resection. The locations were oral cavity (n=32), hypopharynx (n=27), mandible (n=12), skull base (n=5), scalp and skin (n=6) and midface (n=4). The donor sites of free flaps included the rectus abdominis (n=32), anterolateral thigh (n=10), jejunum (n=25), fibula (n=11), latissimus dorsi (n=4), forearm (n=3) and scapula (n=1). The sizes of the cutaneous/musculocutaneous flaps ranged from 4 cm x 5 cm to 14 cm x 24 cm. The lengths of the fibula were 4-16 cm, of jejunum 9-20 cm. RESULTS: The overall free flap success rate was 92% (79/86). Of 32 oral cavity defects, 22 were reconstructed by rectus abdominis (69%) and 10 by anterolateral thigh flaps (31%). Of 27 hypopharyngeal defects, 25 were restored by jejunum flaps (93%). Eleven of 12 mandibular defects were reconstructed by fibula flaps (92%). Four of 5 defects of skull base were reconstructed by rectus abdominis flaps (80%). The free flaps of rectus abdominis, anterolateral thigh, jejunum and fibula were most frequently used, accounting for 91% (78/86) of all flaps in head and neck defect reconstruction. CONCLUSION: Although head and neck defects represent a complicated spectrum of subsites and loss, these four free flaps can manage most reconstruction problems.

Poly(L-lysine)-modified silica nanoparticles for the delivery of antisense oligonucleotides.

Silica nanoparticles were prepared in a microemulsion system, using polyoxyethylene nonylphenyl ether/cyclohexane/ammonium hydroxide. The surface charge of the particle was modified with PLL [poly(L-lysine)]. PAGE demonstrated the ability of PMS-NP (PLL-modified silica nanoparticles) to bind and protect antisense ODNs (oligonucleotides). The intracellular localization of FITC-labelled ODN was investigated by fluorescence microscopy. The results demonstrated that ODN could be delivered to cytoplasm. Flow-cytometry analysis showed a 20-fold enhancement of ODN delivered by PMS-NP compared with free ODN for a serum-free medium. Blocking efficacy of c- myc antisense ODN, delivered by PMS-NP, was examined in HNE1 and HeLa cell lines. Significant down-regulation of c- myc mRNA levels was observed in both the cell lines. However, the cellular uptake efficiency and antisense effects on target gene decreased in the presence of serum-containing medium. The analysis of the filtration assay showed that PMS-NP interacted with serum proteins. These results indicated that PMS-NP was a suitable delivery vector for antisense ODN, although its delivery efficiency decreased in the presence of a serum-containing medium.