Clinical and radiographic outcomes of lateral sinus floor elevation with simultaneous hydrophilic implants placement: A retrospective study of 2-5 years

AIMS

To investigate the clinical and radiographic outcomes of a chemically modified sandblasted large-grit acid-etched implant (hydrophilic) in lateral sinus floor elevation (LSFE), compared with a conventional one (hydrophobic).

MATERIALS AND METHODS

A retrospective study design was adopted. Patients who received LSFE with simultaneous implant placement were recruited. According to different types of implant surfaces, patients were divided into two groups (the hydrophilic group and the hydrophobic group). Implant survival rate (SR), endo-sinus bone stability on the radiographs, mean probing depths, percentage of bleeding on probing, marginal bone loss, and patient satisfaction were evaluated.

RESULTS

A total of 106 patients with 180 implants (hydrophilic:101, hydrophobic:79) in 119 maxillary sinuses were included. The follow-up period ranged from 2 to 5 years. Three hydrophobic implants and one hydrophilic implant in four different patients failed. The SR of the hydrophilic group was higher than that of the hydrophobic group but without a significant difference (p > .05). The change and change rate of endo-sinus bone height (ΔESBH and RΔESBH) and bone volume (ΔESBV and RΔESBV) in the hydrophilic group were less than those in the hydrophobic group, with a significant difference at 6 months after implantation. No other significant difference was found between the two groups.

CONCLUSION

Within the limitations of this study, both hydrophilic and hydrophobic implants were suitable for LSFE with predictable clinical outcomes. Meanwhile, hydrophilic implants could contribute to the grafted endo-sinus bone stability during healing time.

Development and applications of peri-implantitis mouse models

OBJECTIVE

Peri-implantitis is one of the most common complications of implants. However, its pathogenesis has not been clarified. In recent years, mouse models are gradually being used in the study of peri-implantitis. This review aims to summarize the methods used to induce peri-implantitis in mice and their current applications.

METHOD

Articles of peri-implantitis mouse models were collected. We analyzed the various methods of inducing peri-implantitis and their application in different areas.

RESULTS

Most researchers have induced peri-implantitis by silk ligatures. Some others have induced peri-implantitis by Pg gavage and LPS injection. Current applications of peri-implantitis mouse models are in the following areas: investigation of pathogenesis and exploration of new interventions, comparison of peri-implantitis with periodontitis, the interaction between systemic diseases and peri-implantitis, etc. CONCLUSION: Silk ligature for 2-4 weeks, Pg gavage for 6 weeks, and LPS injection for 6 weeks all successfully induced peri-implantitis in mice. Mice have the advantages of mature gene editing technology, low cost, and short time to induce peri-implantitis. It has applications in the study of pathogenesis, non-surgical treatments, and interactions with other diseases. However, compared with large animals, mice also have a number of disadvantages that limit their application.

Titanium particles in peri-implantitis: distribution, pathogenesis and prospects

Peri-implantitis is one of the most important biological complications in the field of oral implantology. Identifying the causative factors of peri-implant inflammation and osteolysis is crucial for the disease's prevention and treatment. The underlying risk factors and detailed pathogenesis of peri-implantitis remain to be elucidated. Titanium-based implants as the most widely used implant inevitably release titanium particles into the surrounding tissue. Notably, the concentration of titanium particles increases significantly at peri-implantitis sites, suggesting titanium particles as a potential risk factor for the condition. Previous studies have indicated that titanium particles can induce peripheral osteolysis and foster the development of aseptic osteoarthritis in orthopedic joint replacement. However, it remains unconfirmed whether this phenomenon also triggers inflammation and bone resorption in peri-implant tissues. This review summarizes the distribution of titanium particles around the implant, the potential roles in peri-implantitis and the prevalent prevention strategies, which expects to provide new directions for the study of the pathogenesis and treatment of peri-implantitis.

Influence of Dentist-Related Risk Factors on Implant Survival Provided by Dentists Without Structured Training: Results of a Retrospective Cross-Sectional Study

PURPOSE

To evaluate the cumulative survival rate (CSR) of implants placed by Chinese dentists who lacked structured training and to identify the dentist-related risk factors associated with implant failure.

MATERIALS AND METHODS

Data from 2,036 patients who underwent implant-supported restoration at a university-affiliated stomatology hospital were collected. CSR was regarded as the dependent variable. Patient-related characteristics (age, sex, insertion site, and surgical complexity) and dentist-related factors (experience, number of implant brands used, education level, sex, and specialty) were collected as independent variables. The chi-square test was used to identify dentist-related factors for implant failure after addressing patient-related potential confounders using propensity score matching (PSM). Dentist- and patient-related risk factors were further analyzed using multivariable logistic regression within the subgroups.

RESULTS

The CSRs were 98.48% for patients (with single or multiple implants) and 98.86% for implants after 48 to 60 months of observation. Dentists with < 5 years of experience and specialists in implant dentistry were significantly associated with implant failure after addressing potential patient-related confounders. Within the group of dentists with < 5 years of experience, complicated cases were the major risk factor. For the group of specialists in implant dentistry, < 5 years of experience and male patient were the major risk factors.

CONCLUSION

New dentists (< 5 years of experience) and specialists in implant dentistry are considered to be dentist-related risk factors for implant failure. This confirms that a learning curve exists for new specialists to reach the level of proficiency and expertise. Int J Oral Maxillofac Implants 2023;38:553-561. doi: 10.11607/jomi.9969.

Immediate loaded fixed complete dentures supported by implants in patients with a history of periodontitis: A retrospective cohort study of 2 to 7 years

STATEMENT OF PROBLEM

The outcome of implant-supported fixed complete dentures in edentulous patients with a history of periodontitis is unclear.

PURPOSE

The purpose of this retrospective clinical study was to assess the clinical outcomes of immediate loaded fixed complete dentures in individuals with a history of periodontitis and to analyze risk factors related to implant failure.

MATERIAL AND METHODS

A total of 642 implants (146 prostheses) in 119 patients were included. The follow-up period ranged from 2 to 7 years. Implant survival rates, marginal bone loss, mechanical complications, biologic complications, and patient satisfaction were evaluated. The Pearson chi-square test, independent samples t test, and multivariate generalized estimating equation were performed for statistical analysis (α=.05).

RESULTS

Eleven implants in 9 patients failed, leading to overall survival rates of 98.3% at the implant level and 92.4% at the patient level. The mean ±standard deviation marginal bone loss was 0.62 ±0.86 mm, and marginal bone loss did not differ significantly between axial and tilted implants (P>.05). Mechanical complications were detected in 55 (37.7%) definitive prostheses; biologic complications were detected in 318 (49.5%) implants. Smokers had a significantly lower survival rate than nonsmokers (odds ratio: 6.880, P=.013). Bruxers had a significantly higher incidence of mechanical complications than nonbruxers (P<.001).

CONCLUSIONS

The immediate loaded fixed complete denture supported by implants is a suitable treatment option for edentulous patients with a history of periodontitis, with high survival implant rates. Smoking is a risk factor for implant failure. Bruxism may increase the incidence of mechanical complications with implant-supported fixed complete dentures, and the overall biologic complication incidence is comparatively high.

Radiographic bone volume alteration after jaw cyst enucleation with or without simultaneous bone grafts: A prospective randomized study

OBJECTIVE

This study was aimed to evaluate bone healing after jaw cyst enucleation with or without bone substitutes by cone beam computed tomography, and to analyze potential influence factors for bone formation as well.

MATERIALS AND METHODS

Sixty seven jaw cyst patients were randomly assigned to two groups. Thirty three patients in control group accepted cystectomy without any filling material. The rest 34 bone cavities which filled with xenograft (DBBM, Bio-Oss®) and covered by absorbable membrane (Bio-Gide®) were included in the guided bone regeneration (GBR) group. All patients were examined with cone bean computerized tomography before operation, 3 and 6 months after surgery. Linear regression analysis was applied to evaluate the influence factors of bone healing.

RESULTS

There was no significant difference in bone formation rate at 3 months after enucleation, with shrinkage rate (SR) of cystic lesion in control group and GBR group of 26.43 ± 14.98% and 20.78 ± 10.80%, respectively (p > 0.05). Larger shrinkage area in GBR group was detected on postoperative radiographs after 6 months with SR of 60.11 ± 19.23%, when compared to those in patients without filling (6 months SR: 48.63 ± 19.39%, p = 0.018, <0.05). Linear regression analysis showed that cyst size was negatively correlated with bone formation.

CONCLUSION

GBR with bovine xenograft and absorbable membrane showed considerable bone regeneration property in the healing of jaw cystic defects after enucleation of radicular cysts. Cyst size showed a suppressive influence on bone formation.

Cleaning effects of decontamination methods on clinically failed TiUnite implants and their impacts on surface roughness and chemistry: An in vitro pilot study

PURPOSE

To evaluate the in vitro cleaning effects of different decontamination methods and their impacts on surface characteristics using clinically failed TiUnite implants (Nobel Biocare, Kloten, Switzerland).

MATERIALS AND METHODS

Thirty clinically failed TiUnite implants were treated using different decontamination methods. Group 1 (control group) received physiological saline irrigation; Group 2 underwent erythritol powder air polishing (AIRFLOW Master Piezon, EMS Dental, Nyon, Switzerland); Group 3 was treated with erythritol powder air polishing with ethylenediaminetetraacetic acid brushing (FileRite PRC, Pulpdent, Watertown, MA, USA); Group 4 received ultrasonic scaling with polyetheretherketone tips (EMS Dental); Group 5 underwent ultrasonic scaling with polyetheretherketone tips with ethylenediaminetetraacetic acid; and Group 6 was treated with a combination of ultrasonic scaling with polyetheretherketone tips, erythritol powder air polishing and ethylenediaminetetraacetic acid. Surface cleaning effects, quantified by relative contaminated area reduction and visual analogue scale score, as well as surface roughness and chemistry, were assessed after decontamination. The cleaning effects of each decontamination method were also compared between TiUnite and SLA (sandblasted, large-grit acid-etched; Straumann, Basel, Switzerland) implants.

RESULTS

Group 6 showed the highest relative contaminated area reduction (stereoscopic microscopy 83.92%, scanning electron microscopy 96.40%), visual analogue scale score (2.83) and reduction in surface roughness (thread bottom -0.78 μm, tip -1.35 μm), as well as an almost maximal decrease in the proportion of carbon (thread bottom -12.33%, tip -8.77%) and increase in that of titanium (thread bottom 13.71%, tip 10.73%). Polyetheretherketone remnants were observed in Groups 4 and 5 but appeared to be reduced in Group 6. When comparing the outcomes with those for SLA implants, no significant differences were found.

CONCLUSION

Within the limitations of the present study, the combination of ultrasonic scaling with polyetheretherketone tips, erythritol powder air polishing and ethylenediaminetetraacetic brushing achieved reasonable cleaning effects. The original surface modification did not seem to have any impact on the decontamination results for any of the methods examined.

Effects of Antibiotic Use on Saliva Antibody Content and Oral Microbiota in Sprague Dawley Rats

Antibiotics are often used to treat systemic diseases not associated with the oral cavity. This application of antibiotics may affect the healthy oral microbiota community, as it destroys the balance between specific bacterial populations throughout the ecosystem and may lead to dysbacteriosis. We hypothesized that the effects on antibiotics on oral microbiota regulation and function would affect antibody content in saliva, depending on the antibiotic type. To address this, a total of 24 Sprague Dawley rats (divided into 4 cages, 6 per pen) were administered amoxicillin (AMX), spiramycin (SP), metronidazole (MTZ), or water (control) daily for 14 days (gavage). After treatment was completed, high-throughput sequencing of 16S rRNA genes was used to determine changes in the composition, metabolic function, and diversity of oral microbiota in the rats. Enzyme-linked immunosorbent assay was used to detect antibodies in saliva, including SIgA, IgG, and IgM. Results showed that AMX, MTZ, and SP significantly affected oral microbiota composition, diversity, and metabolic function in rats. AMX induced substantial changes in the rat salivary antibody concentrations. At the genus level, the relative abundance of Rothia and Haemophilus was higher in the AMX group than in the other groups. In conclusion, antibiotics-induced changes in oral microbiota populations may be associated with changes in salivary antibody concentrations. However, the specific interaction mechanisms remain unknown, and it is still unclear whether significant changes in the oral microbiota cause changes in salivary antibody concentrations or vice versa.

Retrospective Study of Short Versus Standard Posterior Implants and Analysis of Implant Failure Risk Factors

PURPOSE

To compare the clinical and radiographic outcomes of short implants (≤ 8 mm) vs standard implants (> 8 mm, < 10 mm) and to uncover risk factors influencing implant failure in short implants.

MATERIALS AND METHODS

Short and standard implants were compared in the aspect of survival rates, biologic and mechanical complications, and marginal bone loss. To analyze risk factors of implant failure in short implants, several variables were taken into consideration, including sex, age, time interval, arch, implant brand, additional surgery, prosthesis material, restoration, smoking status, and crown-root ratio.

RESULTS

Three hundred twenty-one short implants and 136 standard implants were retrospectively followed up from 12 to 104 months with an average of 40 months (3.33 years) in short implants and 34 months (2.83 years) in standard implants. The survival rates of short implants were 95.6% at the implant-based analysis and 94.9% at the patient-based analysis, and rates of 96.3% and 94.0%, respectively, were calculated for standard implants. No statistically significant differences were observed between short and standard implants with respect to survival rate, complications, or marginal bone loss. The failure rates were 4.2% for implants and 5.4% for patients in total implants with an average of 38 months (3.17 years). In analyzing risk factors of short implants for survival rate, single short implants resulted in a higher failure rate compared with splinted short implants, while no significant variable was found in standard implants.

CONCLUSION

Short implants tend to be a reliable alternative in atrophic posterior regions. Splinted prostheses were more ideal for short implant restorations.

Microbial profiles of peri-implant mucositis and peri-implantitis: Submucosal microbial dysbiosis correlates with disease severity

OBJECTIVE

To investigate the microbiome characteristics of peri-implant mucositis (PM) and peri-implantitis (PI), and to analyse the correlation between disease severity and submucosal microbial dysbiosis.

MATERIALS AND METHODS

A cross-sectional study design was conducted. Submucosal biofilm samples from 27 PM sites and 37 PI sites from 64 patients were collected and analysed using 16S rRNA gene sequencing (Illumina). Differences in microbiological profiles between PM and PI were evaluated using the α-diversity, β-diversity and linear discriminant analysis effect size (LEfSe) analysis. The relative abundances of the taxa at the phylum and genus levels were compared using the Wilcoxon rank test and logistic regression. The microbial dysbiosis index (MDI) was calculated, and its relationship with clinical measurements (probing depth, bleeding on probing and marginal bone loss, among others) was analysed using Pearson's correlation coefficient.

RESULTS

The overall microbiome distribution in the PM and PI sites was similar according to α- and β-diversity. Twenty-three taxa at the genus level and two taxa at the phylum level showed significant differences in relative abundance between the two clinical classifications. Five taxa at the genus level were screened out for the MDI calculation after logistic regression. No clinical measurements but marginal bone loss showed a significant positive correlation with microbial dysbiosis.

CONCLUSION

The microbiome richness, diversity and distribution were similar in PM and PI sites, including both common periodontal bacteria and novel species. In addition, an increase in marginal bone loss was significantly associated with submucosal microbial dysbiosis.

Antimicrobial photodynamic therapy versus antibiotics as an adjunct in the treatment of periodontitis and peri-implantitis: A systematic review and meta-analysis

BACKGROUND

Clinical efficacy of antimicrobial photodynamic therapy (aPDT) as compared to antibiotics in periodontitis and peri-implantitis has been tested in several clinical trials. Yet controversial results were reported. The aim of the present study was to answer the question: "Will adjunctive antimicrobial photodynamic therapy be more effective than antibiotics agent in the treatment of periodontitis and peri-implantitis?".

METHODS

Publications compared outcomes between aPDT and antibiotics in adult patients with periodontitis or peri-implantitis, containing more than 3-month follow-up duration, were involved in the systematic review and meta-analysis. PubMed, EMBASE and Cochrane Central were searched until December of 2020. Clinical parameters including pocket probing depth (PPD), clinical attachment level (CAL), and bleeding on probing (BOP) were evaluated. The risk of bias was assessed by Cochrane Collaboration Tool. Weighted mean differences (WMD), 95 % confidence interval(CI) and heterogeneity were estimated by Review Manager software.

RESULTS

10 trials in periodontitis and 5 trials in peri-implantitis were included. Meta-analysis outcomes revealed equal clinical evidence for aPDT and antibiotics in periodontitis and peri-implantitis. In addition, aPDT significantly reduced the red complex in both diseases. However, owing to the heterogeneity of protocols in articles and the limited number of studies, the comparative conclusion remained unconfirmed.

CONCLUSION

aPDT can be considered as an alternative to antibiotics in the treatment of peri-implantitis and periodontitis. Given that high heterogeneity in outcome was found in this review, future long-term clinical trials with standard aPDT and antibiotic treatment should be tested to arrive at a firm conclusion.

Changes in the surface topography and element proportion of clinically failed SLA implants after in vitro debridement by different methods

OBJECTIVE

To evaluate the surface topography and element proportion changes in clinically failed implants after different modalities in vitro debridement and to compare the cleaning effect of different method combinations.

MATERIAL AND METHODS

Thirty clinical failed implants were treated by different debridement methods in vitro as follows: Group 1: physiologic saline irrigation; Group 2: glycine powder air polishing; Group 3: glycine powder air polishing + ethylenediaminetetraacetic acid (EDTA); Group 4: polyetheretherketone (PEEK) tip ultrasonic scaling; and Group 5: PEEK tip ultrasonic scaling + EDTA. The relative contaminated area reduction (RCAR), visual analogue scale (VAS, the higher value means, the better cleaning effect) and surface roughness were assessed using scanning electron microscopy (SEM), stereoscopic microscopy (SM) and white light interferometry (WLI). Surface chemistry was determined by energy dispersive spectroscopy (EDS).

RESULTS

Group 4 and Group 5 showed higher RCARs (82.90%, 82.89%), VAS scores (2.61, 2.33) and roughness reductions (-0.85 μm, -1.80 μm). Group 3 attained the highest decrease of C% (carbon, -26.67%), O% (oxygen, -13.71%) and N% (nitrogen, -5.66%), and the highest increase of Ti% (titanium, 49.67%). PEEK remnants were detected on the implant surface of Groups 4 and 5.

CONCLUSION

Within the limitation of the present in vitro design, PEEK tip ultrasonic scaling was more effective in eliminating visible contamination, while glycine powder air polishing combined with EDTA treatment was more conducive to expose the original surface element distribution. Both methods have their own advantages in decontamination, but none of them could reconstruct the surface as the pristine implant.

The comparative evaluation of transcrestal and lateral sinus floor elevation in sites with residual bone height ≤6 mm: A two-year prospective randomized study

OBJECTIVES

To compare clinical and radiographic outcomes between transcrestal sinus floor elevation (TSFE) and lateral sinus floor elevation (LSFE) approaches of simultaneous implant placement in atrophic maxilla.

MATERIALS AND METHODS

Patients with a residual bone height (RBH) ≤6 mm were enrolled and randomly assigned to TSFE and LSFE groups. Patients in both groups simultaneously underwent sinus floor elevation with bovine-derived xenograft and implant placement. Clinical and radiographic results were evaluated immediately after surgery and after 6, 12, 18, and 24 months. The endo-sinus bone gain (ESBG), apical implant bone height (ABH), endo-sinus bone-implant contact rate (EBICR), and crestal bone level (CBL) were assessed using panoramic radiographs.

RESULTS

Forty-one implants (TSFE: 21, LSFE: 20) were placed in cases with a mean RBH of 3.77 ± 1.16 mm. All implants obtained clinical success and satisfactory ESBG at 24 months. No significant differences were found in ESBG and ABH between two groups immediately after surgery, but LSFE group showed significantly higher values than TSFE group thereafter. Grafts in TSFE group reached stability 6 months earlier than that in LSFE group. In both groups, EBICR was almost 100%, and CBL showed no detectable changes.

CONCLUSIONS

LSFE can achieve higher ESBG 2 years after surgery. Otherwise, TSFE could be an alternative to LSFE, when the access for lateral window preparation is limited. Both approaches were highly predictable for RBH ≤6 mm during 24-month observation period for the implants placed simultaneously.

Cell therapy of a knee osteoarthritis rat model using precartilaginous stem cells

OBJECTIVE

To explore the effect and mechanism of precartilaginous stem cells (PSCs) engraftment-inducing tissue repair in a knee osteoarthritis (OA) rat model.

MATERIALS AND METHODS

Knee osteoarthritis (OA) model was constructed in Sprague Dawley (SD) rats by partial removal of the medial meniscus of the right knee. PSCs were engrafted by injecting precartilaginous stem cells (PSCs) into the right knee cavity. At 4 and 8 weeks after model construction, the serum levels of interleukine (IL)-1β, tumor necrosis factor (TNF)-α, and IL-6 were assessed using enzyme-linked immunosorbent assay (ELISA). Hematoxylin-eosin (HE) staining was performed to assess the histopathology of synovial membrane and cartilage. Western blot analysis was used to assess Notch1, Bcl-2 and Bax levels in the articular cartilage.

RESULTS

At 4 and 8 weeks, OA rats demonstrated significantly higher IL-1β, TNF-α, and IL-6 levels than normal rats (p < 0.05), whereas PSCs treatment prominently attenuated IL-1β upregulation (p < 0.05). In OA rats, the number of chondrocytes dramatically decreased over time in OA rats, with disruption of chondrocytes organization and cell layers. PSCs alleviated the deterioration of cartilage, as evidenced by the relatively smooth articular surface, distinct tidemark and clear cell layers. The model and treatment groups demonstrated substantially higher Notch1 expression. The Bcl-2/Bax value in the OA rats was lower than the control group, while PSCs treatment led to increase in Bcl-2/Bax value.

CONCLUSIONS

PSCs treatment downregulated the expression of inflammatory cytokines, alleviating osteoarthritis in the knee of rats. Notch1 signaling pathway plays an important role in this ameliorating effect of PSCs treatment.

Likelihood of needing facial bone augmentation in the anterior maxilla of Chinese Asians: A cone beam computed tomography virtual implant study

BACKGROUND

The perfect position and axis of an implant is often limited by the morphology of the alveolar ridge, especially in Asians.

PURPOSE

The aim of this study was to investigate the frequency at which ideal implant placement position in the anterior maxilla of Chinese Asians would require facial bone augmentation given by an initial facial bone profile.

MATERIALS AND METHODS

Implants were virtually placed in 303 sites without tooth loss in the anterior maxilla. The incidence and characters of implant facial plate fenestration were analyzed. If there was no facial fenestration, the thinnest buccal plate (TB) amount adjacent to the implant was measured and recorded.

RESULTS

A total of 79 (26.07%) sites showed fenestrations. The mean length, width, and area of exposure in the fenestration sites were 2.94 ± 1.67 mm, 1.52 ± 0.97 mm, and 2.84 ± 3.13 mm² , respectively. In the nonfenestrated sites, the TB of facial bone around the virtual implants was 1.10 ± 0.78 mm. Among the 224 nonfenestrated sites, 126 sites had a TB of less than 1 mm.

CONCLUSIONS

It can be concluded that the initial facial bone profile should be considered when designing restorations and choosing an optimal implant position in the anterior maxilla.

Retrospective study on the clinical outcomes of small-diameter implants supporting fixed prostheses without bone augmentation in the posterior region after 2 to 12 years

BACKGROUND

Small-diameter implants (SDIs: diameter <3.5 mm) are often chosen as an alternative to bone augmentation in clinical practice, but the scientific evidence regarding SDI application in the posterior area remains deficient.

PURPOSE

To evaluate the clinical and radiographic outcomes of SDIs supporting fixed prostheses without bone augmentation in the posterior region, and to analyze the potential influencing factors related to SDI failures.

MATERIALS AND METHODS

Clinical and radiographic data of 243 SDIs in 156 patients were retrospectively assembled after 2 to 12 (mean 4.75) years of follow-up. Implant and prosthesis failures, mechanical and biological complications, and radiographic marginal bone loss (MBL) were evaluated. The influence of patient/implant characteristics and prosthetic design on SDI failures was investigated.

RESULTS

Five implants in five patients failed, contributing to 10-year cumulative survival rates of 97.9% on an implant-based analysis and 96.8% on a patient-based analysis. Biological complications and mechanical complications were detected in 22 (9.1%) and 31 (12.8%) of implants, respectively. No implant fracture was detected. Peri-implant MBL during 10 years was 0.60 ± 0.90 mm on average. The implant type (bone-level or tissue-level) was the only factor that significantly influenced SDI failures.

CONCLUSION

SDIs supporting fixed prostheses in the posterior region achieved predictable long-term clinical outcomes. However, tissue-level titanium SDIs should be avoided where possible.

Cell therapy of a knee osteoarthritis rat model using precartilaginous stem cells

OBJECTIVE

To explore the effect and mechanism of precartilaginous stem cells (PSCs) engraftment-inducing tissue repair in a knee osteoarthritis (OA) rat model.

MATERIALS AND METHODS

Knee osteoarthritis (OA) model was constructed in Sprague Dawley (SD) rats by partial removal of the medial meniscus of the right knee. PSCs were engrafted by injecting precartilaginous stem cells (PSCs) into the right knee cavity. At 4 and 8 weeks after model construction, the serum levels of interleukine (IL)-1β, tumor necrosis factor (TNF)-α, and IL-6 were assessed using enzyme-linked immunosorbent assay (ELISA). Hematoxylin-eosin (HE) staining was performed to assess the histopathology of synovial membrane and cartilage. Western blot analysis was used to assess Notch1, Bcl-2 and Bax levels in the articular cartilage.

RESULTS

At 4 and 8 weeks, OA rats demonstrated significantly higher IL-1β, TNF-α, and IL-6 levels than normal rats (p < 0.05), whereas PSCs treatment prominently attenuated IL-1β upregulation (p < 0.05). In OA rats, the number of chondrocytes dramatically decreased over time in OA rats, with disruption of chondrocytes organization and cell layers. PSCs alleviated the deterioration of cartilage, as evidenced by the relatively smooth articular surface, distinct tidemark and clear cell layers. The model and treatment groups demonstrated substantially higher Notch1 expression. The Bcl-2/Bax value in the OA rats was lower than the control group, while PSCs treatment led to increase in Bcl-2/Bax value.

CONCLUSIONS

PSCs treatment downregulated the expression of inflammatory cytokines, alleviating osteoarthritis in the knee of rats. Notch1 signaling pathway plays an important role in this ameliorating effect of PSCs treatment.

Effectiveness and safety of Mobi-C for treatment of single-level cervical disc spondylosis

Aims

In order to evaluate the effectiveness of the Mobi-C implant in cervical disc degeneration, a randomised study was conducted, comparing the Mobi-C prosthesis arthroplasty with anterior cervical disc fusion (ACDF) in patients with single level cervical spondylosis.

Patients and Methods

From January 2008 to July 2009, 99 patients were enrolled and randomly divided into two groups, those having a Mobi-C implant (n = 51; 30 men, 21 women) and those undergoing ACDF (n = 48; 28 men, 20 women).The patients were followed up for five years, with the primary outcomes being the Japanese Orthopaedic Association score, visual analogue scale for pain and the incidence of further surgery. The secondary outcomes were the Neck Disability Index and range of movement (ROM) of the treated segment.

Results

The incidence of further surgery was found to be statistically significant between the two groups (p = 0.49), with seven ACDF patients requiring further surgery and only one Mobi-C patient requiring re-operation. There were significant differences (p < 0.001) between the two groups in the ROM of the treated segment. However, both Mobi-C surgery and ACDF surgery were effective in improving the patient’s clinical symptoms. Take home message: Mobi-C implant surgery is a safe alternative to ACDF surgery in cervical disc degeneration. Cite this article: Bone Joint J 2016;98-B:829–3.

Plumbagin Protects Against Spinal Cord Injury-induced Oxidative Stress and Inflammation in Wistar Rats through Nrf-2 Upregulation

BACKGROUND

Spinal cord injury causes post-traumatic degeneration through series of biochemical events. This study aims to evaluate the possible protective mechanism of Plumbagin against Spinal cord injury induced oxidative stress and inflammation. Plumbagin is a potent antioxidant and shows anti-carcinogenic, anti-inflammatory and analgesic activities. However, its exact molecular mechanism of action has yet to be explored.

METHODS

We tested the effects of Plumbagin on spinal cord injury induced ROS generation and lipid peroxidation content in wistar rats. Additionally, the expression of 2 important transcription factors NF-κB and Nrf-2 was investigated.

RESULTS

Plumbagin treatment significantly ameliorated oxidative stress through inhibition of ROS and lipid peroxidation with a concomitant increase in antioxidant status. Western blot analysis revealed enhanced nuclear levels of Nrf-2, while NF-κB expression was suppressed during Plumbagin administration. Enzyme linked immunosorbent assay for pro-inflammatory cytokines (TNF-α, IL-1β) showed a significant downregulation followed by Plumbagin treatment in spinal cord injury rats.

CONCLUSION

Taken together, the data suggests potential and novel role of Plumbagin in cytoprotection by modulating NF-κB and Nrf-2 levels against spinal cord injury.

Modulation of K(v)7 potassium channels by a novel opener pyrazolo[1,5-a]pyrimidin-7(4H)-one compound QO-58

BACKGROUND AND PURPOSE

Modulation of K(v)7/M channel function represents a relatively new strategy to treat neuronal excitability disorders such as epilepsy and neuropathic pain. We designed and synthesized a novel series of pyrazolo[1,5-a] pyrimidin-7(4H)-one compounds, which activate K(v)7 channels. Here, we characterized the effects of the lead compound, QO-58, on K(v)7 channels and investigated its mechanism of action.

EXPERIMENTAL APPROACH

A perforated whole-cell patch technique was used to record K(v)7 currents expressed in mammalian cell lines and M-type currents from rat dorsal root ganglion neurons. The effects of QO-58 in a rat model of neuropathic pain, chronic constriction injury (CCI) of the sciatic nerve, were also examined.

KEY RESULTS

QO-58 increased the current amplitudes, shifted the voltage-dependent activation curve in a more negative direction and slowed the deactivation of K(v)7.2/K(v)7.3 currents. QO-58 activated K(v)7.1, K(v)7.2, K(v)7.4 and K(v)7.3/K(v)7.5 channels with a more selective effect on K(v)7.2 and K(v)7.4, but little effect on K(v)7.3. The mechanism of QO-58's activation of K(v)7 channels was clearly distinct from that used by retigabine. A chain of amino acids, Val(224)Val(225)Tyr(226), in K(v)7.2 was important for QO-58 activation of this channel. QO-58 enhanced native neuronal M currents, resulting in depression of evoked action potentials. QO-58 also elevated the pain threshold of neuropathic pain in the sciatic nerve CCI model.

CONCLUSIONS AND IMPLICATIONS

The results indicate that QO-58 is a potent modulator of K(v)7 channels with a mechanism of action different from those of known K(v)7 openers. Hence, QO-58 shows potential as a treatment for diseases associated with neuronal hyperexcitability.

Thermally induced phase transitions and morphological changes in organoclays

Thermal transitions and morphological changes in Cloisite organoclays were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and in situ simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) over the temperature range of 30-260 degrees C. On the basis of DSC and FTIR results, the surfactant component in organoclays was found to undergo a melting-like order-disorder transition between 35 and 50 degrees C. The transition temperatures of the DSC peaks (Ttr) in the organoclays varied slightly with the surfactant content; however, they were significantly lower than the melting temperature of the free surfactant (dimethyldihydrotallowammonium chloride; Tm = 70 degrees C). FTIR results indicated that within the vicinity of Ttr, the gauche content increased significantly in the conformation of surfactant molecules, while WAXD results did not show any change in three-dimensional ordering. Multiple scattering peaks were observed in SAXS profiles. In the SAXS data acquired below Ttr, the second scattering peak was found to occur at an angle lower than twice that of the first peak position (i.e., nonequidistant scattering maxima). In the data acquired above Ttr, the second peak was found to shift toward the equidistant position (the most drastic shift was seen in the system with the highest surfactant content). Using a novel SAXS modeling technique, we suggest that the appearance of nonequidistant SAXS maxima could result from a bimodal layer thickness distribution of the organic layers in organoclays. The occurrence of the equidistant scattering profile above Ttr could be explained by the conversion of the bimodal distribution to the unimodal distribution, indicating a redistribution of the surfactant that is nonbounded to the clay surface. At temperatures above 190 degrees C, the scattering maxima gradually broadened and became nonequidistant again but having the second peak shifted toward a scattering angle higher than twice the first peak position. The changes in SAXS patterns above 190 degrees C could be attributed to the collapse of organic layers due to desorption and/or degradation of surfactant component, which was supported by the TGA data.

[A comparison of SERS of positive and negative nano-silver adsorbing cation and anion molecule]

A study on the negative charge colloid of nano-silver particles with anion and cation molecules has been done. The results of the experiment show that the negative charge colloid of nano-silver particle has no SERS effect when anion molecule adsorbed on its surface. While the cation molecule in adsorbed on its surface the SERS effect is enhanced. The SERS effects are just opposite when the two molecules separately adsorbed on the surface of the positive colloid of nano-silver particles. The paper hypothesizes that strong SERS effect can be got by using proper colloid of nano-silver particles. It is practical to develop the use of SERS.

[The enhanced mechanism of Cl- to SERS in silver colloid]

The SERS is enhanced when KCl is added to silver colloid and cation molecule. The hypothesis supposed that Cl- bridged between nano-silver and molecule, as a result the molecule adsorbing on nano-silver surface is promoted and the SERS is therefore enhanced. The CN- and NH3 can be better adsorbed when they are added separately to the nano-silver particles, Cl- and anion molecule. The SERS reduces when CN- and NH3 are added separately to Cl-, anion molecule and silver colloid. The result is that the CN- and NH3 are so strong that they have replaced Cl- and anion molecules. Therefore the SERS reduces. This has proved the bridge role of Cl-.

Regulation of endothelial heme oxygenase activity during hypoxia is dependent on chelatable iron

The regulation of heme oxygenase (HO) activity and its dependence on iron was studied in bovine aortic endothelial cells (BAEC) subjected to hypoxia-reoxygenation (H/R). HO activity was induced by hypoxia (10 h) and continued to increase during the reoxygenation phase. HO-1 protein levels were strongly induced by hypoxia from undetectable levels and remained elevated at least 8 h postreoxygenation. Addition of the Fe(3+) chelator desferrioxamine mesylate (DFO) or the Fe(2+) chelator o-phenanthroline during hypoxia alone or during the entire H/R period inhibited the induction of HO activity and HO-1 protein levels. However, DFO had no effect and o-phenanthroline had a partial inhibitory effect on HO activity and protein levels when added only during reoxygenation. Loading of BAEC with Fe(3+) enhanced the activation of the HO-1 gene by H/R, whereas loading with L-aminolevulinic acid, which stimulates heme synthesis, had little effect. These results suggest that chelatable iron participates in regulating HO expression during hypoxia.

Removal of bedrails on a short-term nursing home rehabilitation unit

Our goal was to determine whether bedrails could be removed safely on a geriatric rehabilitation unit. Staff attended in-services about bedrails, assessment, and possible alternatives. Residents in the study group were assessed by an interdisciplinary team, following which a determination was made about the use of bedrails or alternatives. Eighty percent of residents in the study group were free of bedrails, which suggests that bedrails can be safely removed from most short-stay nursing home rehabilitation residents.

Pravastatin increases survival and inhibits natural killer cell enhancement factor in liver transplanted rats

Pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has been shown to decrease the number of acute rejection episodes in cardiac and renal transplant patients. This study evaluates the effects of pravastatin on survival of rats following liver transplant and attempts to elucidate the mechanisms of these effects. Both survival and natural killer cell enhancing factor (NKEF) studies utilized Dark Agouti rats for donor livers transplanted into Brown Norway rats as recipients. All rats received daily low-dose cyclosporine (CsA) 2 mg/kg/day by gavage. The treated groups also received gavage doses of pravastatin, 20 mg/kg/day. Survival data were analyzed by the method of Kaplan-Meier and log-rank chi 2 tests for statistical significance. For NKEF evaluation, rats were sacrificed at varying time points; total RNA was extracted from the liver and hybridized with 32P-radiolabeled NKEF DNA probes in the Northern blot technique. Radiographs were quantitated using densitometry. Data were analyzed by two-way ANOVA. Actuarial survival was improved (P < < 0.05) in rats treated with pravastatin in addition to low-dose CsA (n = 41, CsA alone n = 74). Less fibrosis and chronic rejection was seen on histological section in the treated animal livers, P < 0.05, NKEF was seen maximally at Days 5-15 tapering off at Day 21. NKEF-a and NKEF-b levels were significantly decreased in the animals treated with CsA and pravastatin compared to CsA alone in the group of animals < 16 days postop (P < < 0.05). Pravastatin improves survival in rats following OLT and while the mechanism is still unknown, inhibition of natural killer cell enhancement factor may represent an alteration in the overall immune response.

Orthostatic change in blood pressure in non-demented, ambulatory nursing home patients

While postural hypotension was present in almost 20% of ambulatory patients of this long-term institution, associated symptoms were infrequent. A comparison of the groups with and without a history of falls in the prior year revealed no relationship to the presence of postural hypotension and no relationship to a number of medications which have been reported to be associated with orthostatic hypotension. Blood pressure readings should be obtained at 1,3 and 5 min after assuming the erect position as significant falls in blood pressure were found at each interval.

[The analysis of foreign bodies in the anterior chamber in 165 cases]

One hundred and sixty-six eyes of 165 patients with foreign bodies in the anterior chamber who were treated at our center from 1966 to 1988 were retrospectively reviewed. Among them there were 109 eyes with nonmetal foreign bodies, 55 eyes with metal foreign bodies and three eyes with foreign bodies of unknown nature. Most of these foreign bodies were stone or iron. 83.6% of the patients were in the age range from 7 to 40 years, and the left eyes were affected more than the right eyes. Mostly, the foreign bodies were located on the surface of iris (97 cases) and at the anterior chamber angle (40 cases). The rates of blindness were 27.8% and 16.3% before and after operation. The postoperative visual acuity were: 0.05-0.2 in 27 eyes, 0.3-0.9 in 66 eyes, greater than 1.0 in 43 eyes and the rest of the eyes lower than 0.05. The presurgery treatment such as miosis and reduction of intraocular pressure, the selection of operative methods according to the nature, size, location of the foreign bodies and tissue wrapped up were discussed. If combined procedures should be done, it is better to remove the foreign bodies first and then perform the operation for complications.

[The analysis of foreign bodies in the anterior chamber in 165 cases]

One hundred and sixty-six eyes of 165 patients with foreign bodies in the anterior chamber who were treated at our center from 1966 to 1988 were retrospectively reviewed. Among them there were 109 eyes with nonmetal foreign bodies, 55 eyes with metal foreign bodies and three eyes with foreign bodies of unknown nature. Most of these foreign bodies were stone or iron. 83.6% of the patients were in the age range from 7 to 40 years, and the left eyes were affected more than the right eyes. Mostly, the foreign bodies were located on the surface of iris (97 cases) and at the anterior chamber angle (40 cases). The rates of blindness were 27.8% and 16.3% before and after operation. The postoperative visual acuity were: 0.05-0.2 in 27 eyes, 0.3-0.9 in 66 eyes, greater than 1.0 in 43 eyes and the rest of the eyes lower than 0.05. The presurgery treatment such as miosis and reduction of intraocular pressure, the selection of operative methods according to the nature, size, location of the foreign bodies and tissue wrapped up were discussed. If combined procedures should be done, it is better to remove the foreign bodies first and then perform the operation for complications.