Targeting Treg cells in cancer immunotherapy

Foxp3‐expressing regulatory T (Treg) cells, which are indispensable for preventing autoimmunity, also suppress effective tumor immunity. Treg cells abundantly infiltrate into tumor tissues, which is often associated with poor prognosis in cancer patients. Removal of Treg cells enhances anti‐tumor immune responses but may also elicit autoimmunity. A key issue in devising Treg‐targeting cancer immunotherapy is, therefore, how to specifically deplete Treg cells infiltrating into tumor tissues without affecting tumor‐reactive effector T cells, while suppressing autoimmunity. This can be achieved by differentially controlling Treg and effector T cells by various ways. In this review, we discuss how tumor‐infiltrating Foxp3⁺ Treg cells hamper effective anti‐tumor immune responses especially in tumor tissues and how they can be specifically targeted for augmenting tumor immunity but not autoimmunity.     

Association Between Anti-Helicobacter pylori Antibody Seropositive and De Novo Gallstone Formation After Laparoscopic Sleeve Gastrectomy for Japanese Patients with Severe Obesity

Purpose

Patients who have undergone bariatric surgery are at risk for gallstone formation. However, the incidence of gallstone formation after bariatric surgery has not been adequately studied in the Japanese population. We aimed to elucidate the incidence and risk factors for gallstone formation after laparoscopic sleeve gastrectomy (LSG) for Japanese patients with severe obesity.

Methods

We conducted a retrospective cohort study among patients with severe obesity treated with LSG between April 2017 and June 2020 at two institutions. Patients who had received previous cholecystectomy, had preoperative gallstones, and had received postoperative prophylactic ursodeoxycholic acid were excluded. Body weight, body mass index, and blood data were collected at each follow-up visit before and after the surgery. Follow-up abdominal ultrasonography was performed 6–12 months after surgery, and the incidence of gallstones was calculated. The association between the data and gallstone formation was evaluated.

Results

During the study period, we performed LSG for 98 patients. Of these, 61 cases remained by above conditions and were examined using abdominal ultrasonography over 6 months after surgery. The incidence of gallstones was 23.0% and that of symptomatic gallstones was 3.3%. Anti-Helicobacter pylori antibody seropositive and titer were the only factors that showed significant association with de novo gallstone formation after LSG.

Conclusions

Anti-Helicobacter pylori antibody seropositive may be associated with de novo gallstone formation after LSG for Japanese patients with severe obesity.

Graphical abstract

     

Thermal expansion coefficient of dental composites measured with strain gauges

Objectives. A simple test method was developed to determine the coefficient of thermal expansion of prevailing restorative resin composites and to study the transient behavior as a function of temperature and repeated thermocycles.Methods. Strain gauges were used to determine the thermal expansion for seven commonly used restorative resin composites by measuring the instantaneous strain along with temperature change. The temperature was measured by means of a thermocouple, the tip of which was embedded in the composite. The differences among the test groups were analyzed using ANOVA, followed by Scheffé's multiple comparisons test.Results. The coefficient of thermal expansion determined for the composites tested was: 22.5 ± 1.4 × 10⁻⁶/°C (Z-100), 23.5 ± 1.4 × 10⁻⁶/°C (P-50), 32.6 ± 1.6 × 10⁻⁶/°C (Herculite XR), 34.1 ± 1.8 × 10⁻⁶/°C (APH), 35.4 ± 1.4 × 10⁻⁶/°C (Conquest), 41.6 ± 1.5 × 10⁻⁶/°C (Silux Plus), 44.7 ± 1.2 × 10⁻⁶/°C (Heliomolar). The coefficient was almost linear in the considered temperature range (26–75°C) for all composites (r > 0.99) and decreased with each consecutive thermocycle (p < 0.1).Significance. Thermally induced loads, introduced into restored teeth by the mismatch of the coefficient of thermal expansion of the tooth and the restorative material, may be related to microleakage and wear problems. A highly filled hybrid composite such as Z-100 had a coefficient of thermal expansion closest to that of the tooth crown, confirming other studies which demonstrated the benefits of high filler loading in matching the properties of the dental hard tissues.     

Correlation of noncarious cervical lesion size and occlusal wear in a single adult over a 14-year time span

STATEMENT OF PROBLEM: Noncarious cervical lesions are described as having a multifactorial cause, with occlusal trauma and toothbrush abrasion frequently mentioned as major factors. Finite element modeling studies have demonstrated a relocalization of occlusal stresses to the cervical area due to flexure of the crown. This may cause microcracking, especially under tensile stresses, that will lead to a loss of enamel and dentin in the cervical region. Clinical confirmation of an occlusal cause for noncarious cervical lesions has been difficult to obtain. PURPOSE: This study investigated whether occlusal wear was correlated with an increase in the size of noncarious cervical lesions. MATERIAL AND METHODS: Loss of contour at occlusal and cervical sites on 3 teeth of a single individual was measured using digital and visualization techniques at 3 time intervals over a 14-year time span. The 1983 baseline casts and 1991, 1994, and 1997 clinical impressions of a single adult patient with existing noncarious cervical lesions were replicated in epoxy. Surfaces of all replicas were digitized with a contact digitizing system. Sequential digitized surfaces were fit together and analyzed using AnSur-NT surface analysis software. Clinical losses of surface contour by volume and depth of the left mandibular first molar and first and second premolars were recorded. RESULTS: Nine measurements of cervical volume loss (range 0.9 to 11.5 mm(3)) and 9 corresponding measurements of occlusal volume loss (range 0.39 to 7.79 mm(3)) were made. The correlation between occlusal and cervical volume loss was strong (r(2)=0.98) and significant (P<.0001). CONCLUSION: For the single adult patient in this study, there was a direct correlation between occlusal wear and the growth of noncarious cervical lesions.     

Application of capacitively coupled electric field enhances periimplant osteogenesis in the dog mandible

PURPOSE: Expeditious postoperative ingrowth of bone into dental implants is desired for clinically successful fixation of oral implants. The present study was performed to evaluate the effect of applying a capacitively coupled electric field (CCEF) on periimplant osteogenesis in the dog mandible. MATERIALS AND METHODS: Twelve adult male beagles were used in this study. All of the premolars on both sides of the mandible were removed from each dog. A POI (Ti-6Al-4V) 3-piece implant (3.7 mm in diameter and 8.0 mm in length) whose surface had been treated with anodic oxidation was placed into each test site by self-tapping. Daily application of CCEF (8 h/day) was initiated on the day following the surgery and was continued through the day of sacrifice. A CCEF was induced by an external source delivering 10-Vp-p, 60-kHz sine-wave signals through an oral electrode plate. One side of the mandible of each dog was treated with CCEF, while the other side was not. On the control side, an oral electrode plate was attached for 8 hours per day, but CCEF was not applied. The effect of daily application of CCEF on the ingrowth of bone into the implant was examined at 14, 21, or 30 days after implant placement. A fourth control group was not treated with CCEF and was maintained for 90 days to confirm that CCEF treatment enhances bone ingrowth in dental implants. RESULTS: Daily application of CCEF significantly increased the bone-contact ratio at days 14, 21, and 30 after implant placement in comparison with the respective controls. The bone-area ratios of the 14- and 21-day CCEF-treated groups were significantly larger than those of the respective controls and were similar to those of the 90-day control group. CONCLUSION: CCEF treatment increases periimplant osteogenesis in the dog mandible, confirming its usefulness in oral implantology.     

Rapid detection of Actinobacillus actinomycetemcomitans using a loop-mediated isothermal amplification method

INTRODUCTION: Actinobacillus actinomycetemcomitans has been implicated in the etiology of aggressive periodontitis. In this study, we applied a novel nucleic acid amplification method, called loop-mediated isothermal amplification (LAMP), which amplifies DNA with high specificity, efficiency and rapidity under isothermal conditions, allowing the rapid detection of A. actinomycetemcomitans. METHODS: We designed the primers for detecting A. actinomycetemcomitans and evaluated the specificity and sensitivity of the assay. RESULTS: The LAMP primers used in this study successfully amplified serotypes a-e of A. actinomycetemcomitans, while other oral bacteria were not amplified. By measuring the precipitation of magnesium pyrophosphate, we could quantify the chromosomal DNA of A. actinomycetemcomitans. The detection limits using the real-time turbidimetry analysis were 5.8 x 10(2)-5.8 x 10(7) copies of A. actinomycetemcomitans template DNA per reaction tube. In addition, the LAMP assay was used for the rapid detection of A. actinomycetemcomitans in clinical specimens from eight individuals. The results with the LAMP method were similar to those using conventional polymerase chain reaction. CONCLUSION: Our results suggest that the LAMP-based assay is very useful for the rapid detection of A. actinomycetemcomitans.     

Stem cell properties of human periodontal ligament cells

BACKGROUND AND OBJECTIVE: Stem cells have been used for regenerative therapies in various fields. The proportion of cells that possess stem cell properties in human periodontal ligament (PDL) cells is not yet well understood. In this study, we quantitatively characterized human PDL cells to clarify their stem cell properties, including self-renewal, multipotency, and stem cell marker expression. MATERIAL AND METHODS: PDL cells were obtained from extracted premolar or wisdom teeth, following which a proliferation assay for self-renewal, a differentiation assay for multipotency, immunostaining for STRO-1, and fluorescence-activated cell sorter (FACS) analysis for stem cell markers (including CD105, CD166, and STRO-1) were performed. RESULTS: Approximately 30% of 400 PDL cells were found to possess replicative potential and formed single-cell colonies, and 30% of these colonies displayed positive staining for STRO-1, 20% differentiated into adipocytes and 30% differentiated into osteoblasts. FACS analysis revealed that PDL cells, including cell populations, expressed the stem cell markers CD105, CD166, and STRO-1. CONCLUSION: The findings of this study indicated that PDL cells possess crucial stem cell properties, such as self-renewal and multipotency, and express the mesenchymal stem cell markers CD105, CD166, and STRO-1 on their cell surface, although there were some variations. Thus, PDL cells can be used for periodontal regenerative procedures.     

Relationship between masseter muscle size and maxillary morphology

The aim of this study was to investigate the relationship between masseter muscle size and craniofacial morphology, focusing on the maxilla. Twenty-four patients (11 males and 13 females; mean age 27.6 ± 5.6 years) underwent cephalometric analyses. Ultrasonography was used to measure the cross-sectional area (CSA) of the masseter muscle and bite force was measured using pressure sensitive film. The results showed that CSA-relaxed was positively correlated with upper anterior face height (UAFH)/total anterior face height (TAFH) and negatively with lower anterior face height (LAFH)/TAFH and LAFH (P < 0.05). CSA-clenched was correlated positively with SN-palatal, FH-palatal, UAFH/TAFH, and lower posterior face height (LPFH)/total posterior face height (TPFH) and negatively with LAFH/TAFH, LAFH, upper posterior face height (UPFH)/TPFH, and UPFH (P < 0.05). Bite force was positively correlated with LPFH/TPFH and negatively with UPFH/TPFH (P < 0.05). As the masseter became larger, the anterior maxillary region tended to shift downwards relative to the cranial base, whereas the posterior region tended to shift upwards. The decrease in LAFH/TAFH and increase in LPFH/TPFH as the size of the masseter muscle increases may be influenced not only by the inclination of the mandibular plane but also by the clockwise rotation of the maxilla.