Purpose

It has been reported that low-level semiconductor diode lasers could enhance the wound healing process. The periodontal ligament is crucial for maintaining the tooth and surrounding tissues in periodontal wound healing. While low-level semiconductor diode lasers have been used in low-level laser therapy, there have been few reports on their effects on periodontal ligament fibroblasts (PDLFs). We performed this study to investigate the biological effects of semiconductor diode lasers on human PDLFs.

Methods

Human PDLFs were cultured and irradiated with a gallium-aluminum-arsenate (GaAlAs) semiconductor diode laser of which the wavelength was 810 nm. The power output was fixed at 500 mW in the continuous wave mode with various energy fluencies, which were 1.97, 3.94, and 5.91 J/cm2. A culture of PDLFs without laser irradiation was regarded as a control. Then, cells were additionally incubated in 72 hours for MTS assay and an alkaline phosphatase (ALPase) activity test. At 48 hours post-laser irradiation, western blot analysis was performed to determine extracellular signal-regulated kinase (ERK) activity. ANOVA was used to assess the significance level of the differences among groups (P<0.05).

Results

At all energy fluencies of laser irradiation, PDLFs proliferation gradually increased for 72 hours without any significant differences compared with the control over the entire period taken together. However, an increment of cell proliferation significantly greater than in the control occurred between 24 and 48 hours at laser irradiation settings of 1.97 and 3.94 J/cm2 (P<0.05). The highest ALPase activity was found at 48 and 72 hours post-laser irradiation with 3.94 J/cm2 energy fluency (P<0.05). The phosphorylated ERK level was more prominent at 3.94 J/cm2 energy fluency than in the control.

Conclusions

The present study demonstrated that the GaAlAs semiconductor diode laser promoted proliferation and differentiation of human PDLFs.

Purpose

The purpose of this study was to compare the bone regeneration effects of cortical, cancellous, and cortico-cancellous human bone substitutes on calvarial defects of rabbits.

Methods

Four 8-mm diameter calvarial defects were created in each of nine New Zealand white rabbits. Freeze-dried cortical bone, freeze-dried cortico-cancellous bone, and demineralized bone matrix with freeze-dried cancellous bone were inserted into the defects, while the non-grafted defect was regarded as the control. After 4, 8, and 12 weeks of healing, the experimental animals were euthanized for specimen preparation. Micro-computed tomography (micro-CT) was performed to calculate the percent bone volume. After histological evaluation, histomorphometric analysis was performed to quantify new bone formation.

Results

In micro-CT evaluation, freeze-dried cortico-cancellous human bone showed the highest percent bone volume value among the experimental groups at week 4. At week 8 and week 12, freeze-dried cortical human bone showed the highest percent bone volume value among the experimental groups. In histologic evaluation, at week 4, freeze-dried cortico-cancellous human bone showed more prominent osteoid tissue than any other group. New bone formation was increased in all of the experimental groups at week 8 and 12. Histomorphometric data showed that freeze-dried cortico-cancellous human bone showed a significantly higher new bone formation percentile value than any other experimental group at week 4. At week 8, freeze-dried cortical human bone showed the highest value, of which a significant difference existed between freeze-dried cortical human bone and demineralized bone matrix with freeze-dried cancellous human bone. At week 12, there were no significant differences among the experimental groups.

Conclusions

Freeze-dried cortico-cancellous human bone showed swift new bone formation at the 4-week healing phase, whereas there was less difference in new bone formation among the experimental groups in the following healing phases.

Erythropoietin (EPO) plays a key regulatory role in the formation of new red blood cells (RBCs). Erythropoietin may also have a role as a therapeutic agent to counteract ischemic injury in neural, cardiac and endothelial cells. One of the limitations preventing the therapeutic application of EPO is its short half-life. The goal of this study was to develop a gene delivery system for the prolonged and controlled release of EPO. The arginine grafted bioreducible polymer (ABP) and its PEGylated version, ABP-PEG10, were utilized to study the expression efficiency and therapeutic effectiveness of this erythropoietin gene delivery system in vitro. Poly(ethylene glycol) (PEG) modification of the ABP was employed to inhibit the particle aggregation resulting from the interactions between cationic polyplexes and the negatively charged proteins typically present in serum. Both the ABP and the ABPPEG10 carriers demonstrated efficient transfection and long-term production of EPO in a variety of cell types. The expressed EPO protein stimulated hematopoietic progenitor cells to form significant numbers of cell colonies in vitro. These data confirm that this EPO gene delivery system using a bioreducible polymeric carrier, either ABP or ABP-PEG 10, merits further testing as a potential therapeutic modality for a variety of clinically important disease states.

Purpose

Implant stability at the time of surgery is crucial for the long-term success of dental implants. Primary stability is considered of paramount importance to achieve osseointegration. The purpose of the present study was to investigate the correlation between the insertion torque and primary stability of dental implants using artificial bone blocks with different bone densities and compositions to mimic different circumstances that are encountered in routine daily clinical settings.

Methods

In order to validate the objectives, various sized holes were made in bone blocks with different bone densities (#10, #20, #30, #40, and #50) using a surgical drill and insertion torque together with implant stability quotient (ISQ) values that were measured using the Osstell Mentor. The experimental groups under evaluation were subdivided into 5 subgroups according to the circumstances.

Results

In group 1, the mean insertion torque and ISQ values increased as the density of the bone blocks increased. For group 2, the mean insertion torque values decreased as the final drill size expanded, but this was not the case for the ISQ values. The mean insertion torque values in group 3 increased with the thickness of the cortical bone, and the same was true for the ISQ values. For group 4, the mean insertion torque values increased as the cancellous bone density increased, but the correlation with the ISQ values was weak. Finally, in group 5, the mean insertion torque decreased as the final drill size increased, but the correlation with the ISQ value was weak.

Conclusions

Within the limitations of the study, it was concluded that primary stability does not simply depend on the insertion torque, but also on the bone quality.

Glucagon-like peptide (GLP-1) encoding dual plasmid (pDNA) system (TSTA (SP-GLP-1)) which is composed of pβ-Gal4-p65 and pUAS-SP-GLP-1 was constructed to improve the production and secretion of expressed GLP-1 by combining the advantages of signal peptide (SP) and two-step transcription amplification (TSTA) system. Its potential for GLP-1 gene delivery system was investigated with employment of arginine- grafted bioreducible polymer (ABP) as a gene carrier. Their polyplexes have about 140 nm-sizes and 20 mV Zeta-potential values. ABP showed no cytotoxicity contrary to PEI25k. It was found in RT-PCR experiments that TSTA-SP pDNA systems showed increased GLP-1 gene transcription level in comparison with mono pDNA system (pβ-GLP-1). It was also observed in GLP-1 ELISA that GLP-1 secretion level of TSTA (SP-GLP-1) pDNA system was 2.7–3.4 times higher than those of pβ-GLP-1 and 1.5–1.7 times than TSTA (GLP-1). Additionally, 2.5–3.5 folds increased level of GLP-1 secretion was found in ABP gene carrier system in comparison with PEI25k. When transfection medium containing secreted GLP-1 was transferred to NIT-1 insulinoma cells, the highest secretion level of insulin was induced in ABP/TSTA (SP-GLP-1) polyplex medium-treated cells. Therefore, this novel system could be utilized as a safe and efficient GLP-1 gene delivery system for type 2 diabetes therapy.

AIM: To evaluate the clinical outcomes and prognostic factors after intravenous corticosteroids following oral corticosteroid failure in active ulcerative colitis patients.

METHODS: Consecutive patients with moderate to severe ulcerative colitis who had been treated with a course of intravenous corticosteroids after oral corticosteroid therapy failure between January 1996 and July 2010 were recruited at Severance Hospital, Seoul, South Korea. The disease activity was measured by the Mayo score, which consists of stool frequency, rectal bleeding, mucosal appearance at flexible sigmoidoscopy, and Physician Global Assessment. We retrospectively evaluated clinical outcomes at two weeks, one month, three months, and one year after the initiation of intravenous corticosteroid therapy. Two weeks outcomes were classified as responders or non-responders. One month, three month and one year outcomes were classified into prolonged response, steroid dependency, and refractoriness.

RESULTS: Our study included a total of 67 eligible patients. At two weeks, 56 (83.6%) patients responded to intravenous corticosteroids. At one month, complete remission was documented in 18 (32.1%) patients and partial remission in 26 (46.4%). Eleven patients (19.7%) were refractory to the treatment. At three months and one year, we found 37 (67.3%) and 25 (46.3%) patients in prolonged response, ten (18.2%) and 23 (42.6%) patients in corticosteroid dependency, 8 (14.5%) and 6 (11.1%) patients with no response, respectively. Total 9 patients were underwent elective proctocolectomy within 1 year. The duration of oral corticosteroid therapy (> 14 d vs ≤ 14 d, P = 0.049) and lower hemoglobin level (≤ 11.0 mg/dL vs >11.0 mg/dL, P = 0.02) were found to be poor prognostic factors for response at two weeks. For one year outcome, univariate analysis revealed that only a partial Mayo score (≥ 6 vs <6, P = 0.057) was found to be associated with a poor response.

CONCLUSION: The duration of oral corticosteroid therapy and lower hemoglobin level were strongly associated with poor outcome.

Background/Aims

A selective 5-hydroxytryptamine (5-HT) type 3 receptor antagonist, ramosetron, inhibits stress-induced abnormal defecation in animals and is currently used as a therapeutic drug for irritable bowel syndrome with diarrhea. The aim of this study is to investigate the effect of ramosetron on altered gastrointestinal (GI) transit.

Methods

Male guinea pigs weighing approximately 300 g were used. The effect of ramosetron was investigated on altered GI transit induced by thyrotropin-releasing hormone (TRH), 5-HT, or mustard oil (MO). GI transit was evaluated by the migration of charcoal mixture from the pylorus to the most distal point, and expressed as a percentage (%) of charcoal migration (cm) of the total length of total small intestine (cm).

Results

The average charcoal transit was 51.3 ± 20.1% in the control (vehicle) group, whereas in the ramosetron group charcoal moved 56.6 ± 21.9%, 46.9 ± 9.14% and 8.4 ± 5.6% of the total small intestine at the concentrations of 10, 30 and 100 µg/kg, respectively. GI transit after administration of TRH (100 µg/kg), 5-HT (10 mg/kg) or MO (10 mg/kg) was accelerated compared to vehicle (5-HT, 94.9 ± 9.22%; TRH, 73.4 ± 14.7%; MO, 81.0 ± 13.7%). Ramosetron inhibited GI transit altered by 5-HT, TRH or MO.

Conclusions

Ramosetron modulated GI transit. We suggest that ramosetron may be therapeutically useful for those with accelerated upper GI transit.

Background/Aims

The symptoms of inflammatory bowel disease (IBD) fluctuate considerably over time. However, it has not been determined whether these symptoms are affected by the menstrual cycle in female IBD patients. This study analyzed the effects of the menstrual cycle on IBD symptom variation.

Methods

This was a prospective study of 91 study subjects (47 IBD patients and 44 healthy controls) who reported daily symptoms and signs throughout their menstrual cycles.

Results

IBD patients had significantly more frequent gastrointestinal symptoms, such as nausea (30% vs 7%, p=0.006), flatulence (53% vs 22%, p=0.003), and abdominal pain as compared to controls (68% vs 38%, p=0.006). The IBD patients also experienced more frequent systemic premenstrual symptoms than the controls (79% vs 50%, p=0.003). More severe abdominal pain (p=0.002) and lower mean general condition scores (p=0.001) were noted during the menstrual phase as compared to the pre- or post-menstrual phase in both groups. IBD patients experienced more frequent premenstrual gastrointestinal symptoms than controls, but their IBD symptoms did not change significantly during the menstrual cycle.

Conclusions

Knowledge of the cyclic alterations in gastrointestinal and systemic symptoms may be helpful in determining the true exacerbation of disease in female IBD patients.

Background/Aims

This study sought to determine the natural course of Crohn's disease (CD) and identify predictors that could indicate responsiveness to corticosteroid (CS) therapy.

Methods

Patients with active CD who were treated with oral CS at a single institution between August 1994 and February 2008 were retrospectively reviewed. The clinical outcomes at 1 month, 4 months, and 1 year after the treatment, as well as clinical and biochemical parameters at the time of CS initiation, were evaluated.

Results

A total of 96 patients with CD were enrolled. In this study, 37 patients achieved complete remission (38.5%), 49 achieved partial remission (51.0%), and 10 (10.4%) showed no response at 1 month after the initiation of CS treatment. At 4 months and 1 year after treatment, 66 (69.5%) and 47 (56.6%) patients showed prolonged response, 22 (23.2%) and 20 (24.1%) showed steroid dependency, and 7 (7.4%) and 16 (19.3%) showed refractoriness, respectively. Nonstricturing and nonpenetrating behaviors and a lower CD activity index demonstrated clinical significance for mid-term or mid- and long-term steroid responses, respectively.

Conclusions

The short-term response rate to initial oral CS therapy in CD was considerably high, but responsiveness thereafter showed a tendency to decrease with time. Clinical parameters reflecting mild inflammation were associated with responsiveness after CS treatment.

As an adjunct to cancer treatment, the use of health functional foods (HFFs) seems to be increasing. However, little is known for the use of HFFs among cancer patients in Korea. The aims of this study were to investigate the exposure rate of HFF use among gastrointestinal (GI) cancer patients and to examine the relationship of socio-demographic and disease-related characteristics with the use of HFFs. A total of 126 patients diagnosed with GI cancer participated in the study. A cross-sectional survey was conducted using a questionnaire. Over a half of all the patients surveyed (n = 67; 53.2%) used HFFs. Patients who were younger, had higher income, or longer duration of disease showed a trend to use HFFs more frequently, even though the tendency was not statistically significant. The most commonly used HFF was vitamin complex (n = 20; 16%), followed by red ginseng (n = 15; 12%), and sweet wormwood (Artemisia annua) (n = 11; 8.8%). About 26% of all responders expressed concerns for using HFFs. The primary concern was 'going against physician's recommendations' (36.8%). About 63% of respondents expressed a desire to consult with their physicians and follow their recommendations. More basic scientific data and educational materials regarding HFFs are required for both health-care professionals and cancer patients. A larger sample and size-controlled groups representing each cancer type will continue to be recruited for participation in this survey.

AIM: To develop a novel endoscopic severity model of intestinal Behcet's disease (BD) and to evaluate its feasibility by comparing it with the actual disease activity index for intestinal Behcet's disease (DAIBD).

METHODS: We reviewed the medical records of 167 intestinal BD patients between March 1986 and April 2011. We also investigated the endoscopic parameters including ulcer locations, distribution, number, depth, shape, size and margin to identify independent factors associated with DAIBD. An endoscopic severity model was developed using significant colonoscopic variables identified by multivariate regression analysis and its correlation with the DAIBD was evaluated. To determine factors related to the discrepancy between endoscopic severity and clinical activity, clinical characteristics and laboratory markers of the patients were analyzed.

RESULTS: A multivariate regression analysis revealed that the number of intestinal ulcers (≥ 2, P = 0.031) and volcanoshaped ulcers (P = 0.001) were predictive factors for the DAIBD. An endoscopic severity model (Y) was developed based on selected endoscopic variables as follows: Y = 47.44 + 9.04 × non-Ileocecal area + 11.85 × ≥ 2 of intestinal ulcers + 5.03 × shallow ulcers + 12.76 × deep ulcers + 4.47 × geographic-shaped ulcers + 26.93 × volcano-shaped ulcers + 8.65 × ≥ 20 mm of intestinal ulcers. However, endoscopic parameters used in the multivariate analysis explained only 18.9% of the DAIBD variance. Patients with severe DAIBD scores but with moderately predicted disease activity by the endoscopic severity model had more symptoms of irritable bowel syndrome (21.4% vs 4.9%, P = 0.026) and a lower rate of corticosteroid use (50.0% vs 75.6%, P = 0.016) than those with severe DAIBD scores and accurately predicted disease by the model.

CONCLUSION: Our study showed that the number of intestinal ulcers and volcano-shaped ulcers were predictive factors for severe DAIBD scores. However, the correlation between endoscopic severity and DAIBD (r = 0.434) was weak.

Purpose

The aim of this study was to provide sex-matched three-dimensional (3D) statistical shape models of the mandible, which would provide cephalometric parameters for 3D treatment planning and cephalometric measurements in orthognathic surgery.

Materials and Methods

The subjects used to create the 3D shape models of the mandible included 23 males and 23 females. The mandibles were segmented semi-automatically from 3D facial CT images. Each individual mandible shape was reconstructed as a 3D surface model, which was parameterized to establish correspondence between different individual surfaces. The principal component analysis (PCA) applied to all mandible shapes produced a mean model and characteristic models of variation. The cephalometric parameters were measured directly from the mean models to evaluate the 3D shape models. The means of the measured parameters were compared with those from other conventional studies. The male and female 3D statistical mean models were developed from 23 individual mandibles, respectively.

Results

The male and female characteristic shapes of variation produced by PCA showed a large variability included in the individual mandibles. The cephalometric measurements from the developed models were very close to those from some conventional studies.

Conclusion

We described the construction of 3D mandibular shape models and presented the application of the 3D mandibular template in cephalometric measurements. Optimal reference models determined from variations produced by PCA could be used for craniofacial patients with various types of skeletal shape.

Even though oncolytic adenovirus (Ad) has been highlighted in the field of cancer gene therapy, transductional targeting and immune privilege still remain difficult challenges. The recent reports have noted the increasing tendency of adenoviral surface shielding with polymer to overcome the limits of its practical application. We previously reported the potential of the biodegradable polymer, poly(CBA-DAH) (CD) as a promising candidate for efficient gene delivery. To endow the selective-targeting moiety of tumor vasculature to CD, cRGDfC well-known as a ligand for cell-surface integrins on tumor endothelium was conjugated to CD using hetero-bifunctional cross-linker SM(PEG)n. The cytopathic effects of oncolytic Ad coated with the polymers were much more enhanced dose-dependently when compared with that of naked Ad in cancer cells selectively. Above all, the most potent oncolytic effect was assessed with the treatment of Ad/CD-PEG500-RGD in all cancer cells. The enhanced cytopathic effect of Ad/RGD-conjugated polymer was specifically inhibited by blocking antibodies to integrins, but not by blocking antibody to CAR. HT1080 cells treated with Ad/CD-PEG500-RGD showed strong induction of apoptosis and suppression of IL-8 and VEGF expression as well. These results suggest that RGD-conjugated bioreducible polymer might be used to deliver oncolytic Ad safely and efficiently for tumor therapy.

Bioreducible cationic polymers (p(DAHa-R/APIb)s) composed of different ratios (a:b = 2:1, 1:1, 1:2) between arginine-grafted diaminohexane (DAH-R) (cell penetrating functionality) and 1-(3-aminopropyl) imidazole (API) (endosome buffering functionality) monomers were synthesized by Michael reaction of N,N’-cystaminebisacrylamide (CBA) with them, in order to study the effect of endosome buffering moiety on arginine-grafted bioreducible polymeric gene carriers. Several experiments displayed a distinct correlation between monomer composition ratios of p(DAH-R/API)s and the polymer features. Increased endosome buffering capacities proportional to API portions was evaluated for p(DAH-R/API)s due to the imidazole group (pKa=6) of API. Increased portions of API non-ionized at physiological pH and resultant decrease of arginine residues also reduced cytotoxicities of the polymers due to less interaction of cellular compartments with less positively charged polymers, but decreased pDNA condensing abilities, Zeta-potential values, cellular uptakes of polyplexes, and finally transfection efficiencies as well. Thus, the predominance of arginine residues over endosome buffering moieties was revealed regarding efficient gene delivery for p(DAH-R/API)s. From transfection results with chloroquine or nigericin, it can be deduced that the endosomal escape of p(DAH-R/API) polyplexes occurs by direct endsome membrane penetration of arginine moieties as well as endosome buffering abilities of the polymers after cellular uptake, which emphasizes the importance of arginine moieties for polymeric gene delivery systems.

Bioreducible polymers, which possess mainly disulfide linkages in the polymer structures, have appeared as ideal gene delivery carriers due to the high stability in extracellular physiological condition and bioreduction-triggered release of genetic materials, as well as decreased cytotoxicity because intracellular cytosol is a reducing environment containing high level of reducing molecules such as glutathione. This review will describe the initiation and recent advances in the development of bioreducible polymers for gene delivery, which includes reducibly cross-linked PEIs, polypeptides, polyion complex micelles, and poly(amido amine)s. There have been extensive researches performed to exhibit great gene delivery efficacy but still several important issues about pharmacokinetics or safety should be answered thoroughly for further rational design of bioreducible polymers having potentials in human gene delivery systems.