The Role of Macrophage Efferocytosis in the Pathogenesis of Apical Periodontitis.

Macrophages (Mφs) play a crucial role in the homeostasis of the periapical immune micro-environment caused by bacterial infection. Mφ efferocytosis has been demonstrated to promote the resolution of multiple infected diseases via accelerating Mφ polarization into M2 type. However, the Mφ efferocytosis-apical periodontitis (AP) relationship has not been elucidated yet. This study aimed to explore the role of Mφ efferocytosis in the pathogenesis of AP. Clinical specimens were collected to determine the involvement of Mφ efferocytosis in the periapical region via immunohistochemical and immunofluorescence staining. For a further understanding of the moderator effect of Mφ efferocytosis in the pathogenesis of AP, both an in vitro AP model and in vivo AP model were treated with ARA290, a Mφ efferocytosis agonist. Histological staining, micro-ct, flow cytometry, RT-PCR and Western blot analysis were performed to detect the inflammatory status, alveolar bone loss and related markers in AP models. The data showed that Mφ efferocytosis is observed in the periapical tissues and enhancing the Mφ efferocytosis ability could effectively promote AP resolution via facilitating M2 Mφ polarization. Collectively, our study demonstrates the functional importance of Mφ efferocytosis in AP pathology and highlights that accelerating Mφ efferocytosis via ARA290 could serve as an adjuvant therapeutic strategy for AP.

SorCS2 is involved in promoting periodontitis-induced depression-like behaviour in mice.

BACKGROUND: Emerging evidence supports the association between periodontitis and depression, although the mechanisms are unclear. This study investigated the role of SorCS2 in the pathogenesis of periodontitis-induced depression. MATERIALS AND METHODS: An experimental periodontitis model was established using SorCS2 knockout mice and their wild-type littermates, and depression-like behaviour was evaluated. The expression of proBDNF signalling, neuronal activity, and glutamate-associated signalling pathways were further measured by western blotting and immunofluorescence. In addition, neuroinflammatory status, astrocytic and microglial markers, and the expression of corticosterone-related factors were measured by immunofluorescence, western blotting, and enzyme-linked immunosorbent assays. RESULTS: SorCS2 deficiency alleviated periodontitis-induced depression-like behaviour in mice. Further results suggested that SorCS2 deficiency downregulated the expression of pro-BDNF and glutamate signalling and restored neuronal activities in mice with periodontitis. Neuroinflammation in the mouse hippocampus was triggered by experimental periodontitis but was not affected by SorCS2 deficiency. The levels of corticosterone and the expression of glucocorticoid receptors were also not altered. CONCLUSION: Our study, for the first time, reveals the critical role of SorCS2 in the pathogenesis of periodontitis-induced depression. The underlying mechanism involves proBDNF and glutamate signalling in the hippocampus, providing a novel therapeutic target for periodontitis-associated depression.

The relationship between lactate dehydrogenase to albumin ratio and all-cause mortality during ICU stays in patients with sepsis: A retrospective cohort study with propensity score matching.

Background: Sepsis is a prevalent and severe medical condition which is frequently observed in the intensive care unit (ICU). Although numerous biomarkers have been identified to predict the prognosis of sepsis, the lactate dehydrogenase to albumin ratio (LDH/ALB ratio) has not been extensively investigated. The principal objective of this study is to assess the relationship between LDH/ALB ratio and all-cause mortality in patients with sepsis. Methods: This study included all adult critically ill patients with sepsis from the Medical Information Mart for Intensive Care IV (MIMIC-IV, version 2.0) database. Propensity score matching (PSM) analysis was conducted to mitigate bias, and Kaplan-Meier curves were performed to evaluate the cumulative survival across different groups. The association between the LDH/ALB ratio and mortality was examined through restricted cubic spline (RCS) analysis and Cox regression analysis. The robustness of the findings was confirmed through subgroup analyses. Additionally, the prognostic capability of the LDH/ALB ratio was further evaluated using receiver operating characteristic (ROC) curve analysis. Results: There were 6059 adult patients with sepsis enrolled in the final analysis. RCS revealed a non-linear relationship between the LDH/ALB ratio and an increased risk of ICU all-cause mortality (χ2 = 46.900, P < 0.001). Following PSM analysis, 1553 matched pairs were obtained. As comparison to the low LDH/ALB ratio group, the mortality rate in the high LDH/ALB ratio group was significantly higher (P < 0.001). Kaplan-Meier curves, both before and after PSM, revealed that the ICU cumulative survival rate for patients with sepsis was significantly lower in the high LDH/ALB ratio group compared to the low LDH/ALB ratio group (χ2 = 93.360, P < 0.001; χ2 = 14.400, P < 0.001). Even after adjusting for a range of potential confounders, multivariate Cox regression analysis indicated that an elevated LDH/ALB ratio was a significant predictor of all-cause mortality in these patients. ROC curve analysis demonstrated that the LDH/ALB ratio had an area under the ROC curve (AUC) of 0.688 for predicting ICU mortality, with a sensitivity of 69.2% and a specificity of 58.6%. Conclusions: An elevated LDH/ALB ratio (≥10.57) was associated with all-cause mortality in critically ill patients with sepsis, and it might serve as a prognostic marker. Clinicians should pay closer attention to sepsis patients presenting with an LDH/ALB ratio of 10.57 or higher.

Glycolytic reprogramming controls periodontitis-associated macrophage pyroptosis via AMPK/SIRT1/NF-κB signaling pathway.

Glycolysis has been demonstrated as a crucial metabolic process in bacteria infected diseases via modulating the activity of pyroptosis. Macrophages are the most abundant immune cells that infiltrated in the infected periodontal tissues, which significantly influence the outcome of periodontitis (PD). However, the effect of glycolysis in regulating macrophage pyroptosis during PD development remains unknown. This study aimed to explore the role of glycolysis in PD-associated macrophage pyroptosis and periodontal degeneration. Clinical specimens were used to determine the emergence of macrophage pyroptosis and glycolysis in periodontal tissues by immunohistochemical analysis and western blot. For an in-depth understanding of the regulatory effect of glycolysis in the progression of macrophage pyroptosis associated periodontitis, both in vivo PD model and in vitro PD model were treated with 2-DG (2-Deoxy-d-glucose), a glycolysis inhibitor. The data showed that the blockade of glycolysis could significantly suppress the lipopolysaccharide (LPS) induced macrophage pyroptosis, resulting in an attenuation of the inflammatory response and bone resorption in periodontal lesions. Furthermore, we revealed that the regulatory effect of glycolysis on macrophage pyroptosis can be mediated via AMPK/SIRT1/NF-κB signaling pathway. Our study unveiled that suppressed glycolysis restrains the activity of PD-associated macrophage pyroptosis, osteoclastogenesis, and subsequent periodontal tissue destruction. These findings extend our knowledge of glycolysis in regulating PD-associated macrophage pyroptosis and provide a potential novel target for PD therapy.

ProBDNF signaling is involved in periodontitis-induced depression-like behavior in mouse hippocampus.

OBJECTIVE: Increasing evidence supports the association between periodontitis and depression. However, the specific mechanisms remain to be further elucidated. The present study aimed to mechanistically investigate the regional roles of proBDNF (the precursor of brain-derived neurotrophic factor) in periodontitis induced depression-like behavior in mice. METHODS: Experimental periodontitis model was established by periodontal injection of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) in 8-week-old male Bdnf-HA/HA mice for 3 weeks. The depression-like behaviors, spontaneous exploratory activity and the level of anxiety were assessed by behavior tests. The activation of microglia and astrocytes, as well as the expression of Interleukin (IL)-1ß and Tumor necrosis factor (TNF)-α in the hippocampus, prefrontal cortex, and cortex were further assessed by immunofluorescence and western blots. The levels of IL-1ß in blood serum and expression of occludin as well as claudin5 in the hippocampus, prefrontal cortex, and cortex were further determined by enzyme-linked immunosorbent assay and western blot. Finally, the expression of proBDNF, its receptors, and mature BDNF (mBDNF), as well as neuronal activity were measured by western blots and immunofluorescence. RESULTS: Pg-LPS successfully induced periodontitis in mice and caused obvious depression-like behavior. Furthermore, we observed an increased activation of astrocytes and microglia, as well as a significant increase in expression of IL-1ß and TNF-α in the hippocampus of mice treated with Pg-LPS, with elevated level of IL-1ß in serum and decreased expression of occludin and claudin5 in the hippocampus. Importantly, we found that the levels of proBDNF and its receptors, SorCS2 and p75NTR, were increased significantly; however, the level of mBDNF was decreased, therefor leading to greater ratio of proBDNF/mBDNF. In addition, we also detected decreased neuronal activity in the hippocampus of mice treated with Pg-LPS. CONCLUSIONS: Our results indicate that Pg-LPS-induced periodontitis could cause depression-like behaviors in mice, and the proBDNF signaling is involved in the process.

The facilitated sensemaking model as a framework for nursing intervention on family members of mechanically ventilated patients in the intensive care unit.

BACKGROUND: Adverse psychological outcomes are prevalent among family members of intensive care unit (ICU) patients. The facilitated sensemaking model (FSM) provides a framework for understanding how intensive care nurses can help these family members overcome situations in which a loved one is critically ill, and reduce adverse psychological outcomes through the facilitated sensemaking process. AIMS: This study aimed to implement FSM-based research performed by ICU nurses and patients' family members to investigate the impact of the facilitated sensemaking intervention on the psychological status of ICU families. METHODS: The intervention was performed by nurses on 80 family members of mechanically ventilated patients, 40 in the control group and 40 in the experimental group. The control group only received routine medical services, while the experimental group received the nursing intervention based on FSM in addition to routine medical services. Anxiety, depression, and post-traumatic stress disorder (PTSD) were measured with the Self-Rating Anxiety Scale, Self-Rating Depression Scale, and Post-Traumatic Stress Disorder Check-List-Civilian Version (PCL-C), respectively. SPSS version 25.0 was applied to analyze the data; what is more, some statistical methods, including descriptive statistical analysis, chi-square test and t-test were further adopted. RESULTS: Before the intervention, there were no significant differences in anxiety, depression, and PTSD of family members of ICU mechanical ventilation patients between the two groups (p > .05). After the intervention, the score of anxiety, depression, and PTSD of family members in the control group and the experimental group were 41.50 ± 5.738 versus 36.50 ± 4.385, p < .001; 45.28 ± 8.089 versus 42.13 ± 5.725, p < .05; and 30.55 ± 7.595 versus 27.55 ± 4.696, p < .05, respectively. The nursing intervention based on FSM significantly alleviated anxiety, depression, and PTSD of mechanical ventilation patients' family members. LINKING EVIDENCE TO ACTION: The nursing intervention based on FSM significantly alleviated anxiety, depression, and PTSD of mechanical ventilation patients' family members. However, there was only a statistically significant difference in the avoidance and numbness symptom cluster of PTSD via the PCL-C. Therefore, the observation time after the implementation of the FSM intervention needs to be extended in the future to clarify the effect of the intervention. Further efforts by advanced practice nurses and the cooperation of patients' families are required to incorporate this intervention into ICU practice.

PD-L1 Inhibits T Cell-Induced Cytokines and Hyaluronan Expression via the CD40-CD40L Pathway in Orbital Fibroblasts From Patients With Thyroid Associated Ophthalmopathy.

Thyroid associated ophthalmopathy (TAO), characterized by T cell infiltration and orbital fibroblast activation, is an organ-specific autoimmune disease which is still short of effective and safety therapeutic drugs. The PD-1/PD-L1 pathway has been reported hindering the progression of Graves' disease to some extent by inhibiting T cell activity, and tumor therapy with a PD-1 inhibitor caused some adverse effects similar to the symptoms of TAO. These findings suggest that the PD-1/PD-L1 pathway may be associated with the pathogenesis of TAO. However, it remains unknown whether the PD-1/PD-L1 pathway is involved in orbital fibroblast activation. Here, we show that orbital fibroblasts from patients with TAO do not express PD-L1. Based on in vitro OF-T cell co-culture system, exogenous PD-L1 weakens T cell-induced orbital fibroblast activation by inhibiting T cell activity, resulting in reduced production of sICAM-1, IL-6, IL-8, and hyaluronan. Additionally, exogenous PD-L1 treatment also inhibits the expression of CD40 and the phosphorylation levels of MAPK and NF-κB pathways in orbital fibroblasts of the OF-T cell co-culture system. Knocking down CD40 with CD40 siRNA or down-regulating the phosphorylation levels of MAPK and NF-κB pathways with SB203580, PD98059, SP600125, and PDTC can both reduce the expression of these cytokines and hyaluronan. Our study demonstrates that the orbital immune tolerance deficiency caused by the lack of PD-L1 in orbital fibroblasts may be one of the causes for the active orbital inflammation in TAO patients, and the utilization of exogenous PD-L1 to reconstruct the orbital immune tolerance microenvironment may be a potential treatment strategy for TAO.

Gremlin aggravates periodontitis via activation of the nuclear factor-kappa B signaling pathway.

BACKGROUND: Gremlin has been reported to regulate inflammation and osteogenesis. Periodontitis is a destructive disease degenerating periodontal tissues, therefore leads to alveolar bone resorption and tooth loss. Based on the importance of Gremlin's bio-activity, the aim of this study is to, in vivo and in vitro, unveil the function of Gremlin in regulating the development of periodontitis and its consequent effects on alveolar bone loss. METHODS: Clinical specimens were used to determine the expression of Gremlin in periodontal tissues by immunohistochemical staining and western blot. Then utilizing the rat periodontitis model to investigate the function of gremlin-regulated nuclear factor-kappa B (NF-κB) pathway during the development of periodontal inflammation and the alveolar bone loss. Last, the regulation of the osteogenesis of human periodontal ligament stem cells (hPDLSCs) by Gremlin under inflamed condition was analyzed by alkaline phosphatase (ALP) and alizarin red staining (ARS). RESULTS: We found clinically and experimentally that the expression of Gremlin is markedly increased in periodontitis tissues. Interestingly, we revealed that Gremlin regulated the progress of periodontitis via regulating the activities of NF-κB pathway and interleukin-1ß (IL-1ß). Notably, we observed that Gremlin influenced the osteogenesis of hPDLSCs. Thus, our present study identified Gremlin as a new key regulator for development of periodontitis. CONCLUSIONS: Our current study illustrated that Gremlin acts as a crucial mediator and possibly serves as a potential diagnostic marker for periodontitis. Discovery of new factors involved in the pathophysiology of periodontitis could contribute to the development of novel therapeutic treatment for the disease.

Screening of differentially expressed miRNAs during osteogenic/odontogenic differentiation of human dental pulp stem cells exposed to mechanical stress.

MicroRNAs (miRNAs) have been demonstrated as crucial transcriptional regulators in proliferation, differentiation, and tumorigenesis. The comprehensive miRNA profiles of osteogenic/odontogenic differentiation of human dental pulp stem cells (hDPSCs) under the condition of mechanical stress remains largely unknown. In this study, we aimed to discover the miRNA expression profiles of hDPSCs exposed to mechanical stress under the osteogenic/odontogenic process. We found that mechanical stress (0.09 MPa and 0.18 MPa, respectively, 30 min/day) significantly promoted the proliferation of hDPSCs since the fifth day. The expressions of DSPP, DMP1, and RUNX2 were significantly increased on day 7 in the presence of 0.09 MPa and 0.18 MPa mechanical stress. On day 14, the expression levels of DSPP, DMP1, and RUNX2 were decreased in the presence of mechanical stress. Among 2578 expressed miRNAs, 5 miRNAs were upregulated and 3 miRNAs were downregulated. Six hub target genes were merged in protein-protein interactions (PPI) network analysis, in which existed only one sub-network. Bioinformatics analysis identified an array of affected signaling pathways involved in the development of epithelial and endothelial cells, cell-cell junction assembly, Rap1 signaling pathway, regulation of actin cytoskeleton, and MAPK signaling pathway. Our results revealed the miRNA expression profiles of osteogenic/odontogenic differentiation of hDPSCs under mechanical stress and identified eight miRNAs that were differentially expressed in response to the mechanical stress. Bioinformatics analysis also showed that various signaling pathways were affected by mechanical stress.

Crosstalk between Wnt/ß-catenin signaling and NF-κB signaling contributes to apical periodontitis.

In physiology conditions, the crosstalk of signaling pathways has been considered to extend the functions of individual pathways and results in a more complex regulatory network. The Wnt3a/ß-catenin and NF-κB signaling pathways have been demonstrated involving in apical periodontitis (AP). As AP progresses, ultimately causes tooth loss. In the present study, we investigate the contribution of the crosstalk between the Wnt3a/ß-catenin and NF-κB signaling pathways to the development of AP. Clinically, utilizing 60 human AP and healthy tissues (30 samples for each group), we found that the expression levels of Wnt3a/ß-catenin and NF-κB were elevated in the Ap tissues compared to that in the healthy group. To further study the roles of Wnt3a/ß-catenin and NF-κB signaling pathways in the development of AP, and the contribution of the crosstalk between these two signaling pathways to AP, we established the AP animal model and observed that, first, both pathways are activated in the AP group compared to the control group. Interestingly, by immunoprecipitation and western blot experiments, we revealed that there is greater interaction between NF-κB (phorspho-p65) and ß-catenin in AP tissues compared to the control tissues. Importantly, when the NF-κB signaling pathway was blocked by its inhibitor, pyrrolidine dithiocarbamate (PDTC), the activity of the Wnt3a/ß-catenin signaling pathway was abolished, and consequently led to the attenuation of the inflammation response in LPS-induced human periodontal ligament cells (hPDLCs). Thus, our data indicate that the crosstalk between Wnt3a/ß-catenin and NF-κB signaling pathway contributes to the development of AP, and provide a therapeutic strategy for the treatment of AP as well.

Treatment of Optic Canal Decompression Combined with Umbilical Cord Mesenchymal Stem (Stromal) Cells for Indirect Traumatic Optic Neuropathy: A Phase 1 Clinical Trial.

PURPOSE: This study was aimed to investigate the safety and feasibility of umbilical cord-derived mesenchymal stem cell (MSC) transplantation in patients with traumatic optic neuropathy (TON). METHODS: This is a single-center, prospective, open-labeled phase 1 study that enrolled 20 patients with TON. Patients consecutively underwent either optic canal decompression combined with MSC local implantation treatment (group 1) or only optic canal decompression (group 2). Patients were evaluated on the first day, seventh day, first month, third month, and sixth month postoperatively. Adverse events, such as fever, urticarial lesions, nasal infection, and death, were recorded at each visit. The primary outcome was changes in best-corrected visual acuity. The secondary outcomes were changes in color vision, relative afferent pupillary defect, and flash visual evoked potential. RESULTS: All 20 patients completed the 6-month follow-up. None of them had any systemic or ocular complications. The change in best-corrected visual acuity at follow-up was not significantly different between group 1 and group 2 (p > 0.05); however, group 1 showed better visual outcome than group 2. Both groups showed significant improvements in vision compared with the baseline (p < 0.05); however, there were no statistically significant differences between the groups (p > 0.05). In addition, no adverse events related to local transplantation were observed in the patients. CONCLUSIONS: A single, local MSC transplantation in the optic nerve is safe for patients with TON.

Follicle-stimulating hormone impairs dental pulp stem cells odontogenic differentiation.

In addition to bone, the dentin-pulp complex is also influenced by menopause, showing a decreased regenerative capacity. High levels of follicle-stimulating hormone (FSH) during menopause could directly regulate bone metabolism. Here, the role of FSH in the odontogenic differentiation of the dentin-pulp complex was investigated. Dental pulp stem cells (DPSCs) were isolated. CCK-8 assays, cell apoptosis assays, Western blotting (WB), real-time RT-PCR, alkaline phosphatase activity assays, and Alizarin Red S staining were used to clarify the effects of FSH on the proliferation, apoptosis and odontogenic differentiation of the DPSCs. MAPK pathway-related factors were explored by WB assays. FSH and its inhibitor were used in OVX rats combined with a direct pulp-capping model. HE and immunohistochemistry were used to detect reparative dentin formation and related features. The results indicated that FSH significantly decreased the odontogenic differentiation of the DPSCs without affecting cell proliferation and apoptosis. Moreover, FSH significantly activated the JNK signalling pathway, and JNK inhibitor partly rescued the inhibitory effect of FSH on DPSC differentiation. In vivo, FSH treatment attenuated the dentin bridge formation and mineralization-related protein expression in the OVX rats. Our findings indicated that FSH reduced the odontogenic capacity of the DPSCs and was involved in reparative dentinogenesis during menopause.

Estrogen deficiency aggravates apical periodontitis by regulating NLRP3/caspase-1/IL-1ß axis.

Estrogen plays critical roles in apical periodontitis and subsequent bone loss, however the mechanism is not clear yet. In this study, we aimed to study the underlying mechanism of estrogen in apical periodontitis using both clinic samples and animal model. Clinically, as estrogen physiologically declines in elder female patients (premenopausal verses postmenopausal patients), we found that the expression level of NLRP3/Caspase-1/IL-1ß signaling pathway was elevated in the infected apical tissues of postmenopausal patients as compared to the premenopausal patients, suggesting that this pathway is involved in the estrogen-mediated apical periodontitis. Furthermore, by analyzing the well-established OVX (estrogen deficiency model) animal model, we confirmed that the expression level of NLRP3/Caspase-1/IL-1ß signaling pathway was also elevated in the infection areas of apical periodontitis in OVX animals. Importantly, as the periodontitis progressed, the subsequent bone loss was aggravated significantly. Thus, taken all these data together, our results demonstrated that the NLRP3/Caspase-1/IL-1ß signaling pathway is involved in the estrogen-mediated apical periodontitis and the consequent bone loss in both human being and animal model. This study may provide a potential target for female apical periodontitis therapy.

Epigenetic silencing of miR-137 induces resistance to bicalutamide by targeting TRIM24 in prostate cancer cells.

Prostate cancer is an important hormone-dependent cancer affecting men. In the initial stages, prostate cancer is often treated using hormone therapy, including bicalutamide. Despite the initial effectiveness of this therapy, the tumor eventually acquires resistance, resulting in recurrence of castration-resistant prostate cancer (CRPC). Dysregulation of microRNA (miRNA) function is one of the putative underlying mechanisms of hormone therapy resistance. Reports have shown that miRNAs act as tumor suppressors in patients with prostate cancer, but the role of these molecules in bicalutamide resistance in prostate cancer cell lines remains unclear. We performed lentiviral miRNA library screening to identify novel miRNAs that modulate the response of human prostate cancer LNCaP cells to the antiandrogen bicalutamide. We found that the tumor suppressor miRNA miR-137 silenced signaling in a spectrum of human cancers and selectively targeted tripartite motif-containing 24 (TRIM24) to suppress tumor proliferation. Silencing of TRIM24 recapitulated the effect of miR-137 on cell proliferation, whereas overexpression of TRIM24 reversed this effect. Real-time reverse transcription PCR analysis revealed a reciprocal relationship between miR-137 and TRIM24 in prostate cancer cell lines and tissues. Mechanistic studies indicated that methyl CpG-binding protein 2 (MeCP2) and DNA methyltransferases (DNMTs) cooperate to promote methylation of the miR-137 promoter and the consequent decreased transcription, leading to enhanced TRIM24 expression and glutamine metabolism. These findings describe a novel mechanism that affects TRIM24 deregulation in human cancers and provide a molecular link between miR-137, TRIM24, and tumor proliferation in CRPC.

FSH aggravates bone loss in ovariectomised rats with experimental periapical periodontitis.

Periapical bone loss is one of the prominent pathological and clinical features of periapical periodontitis. Previous studies have demonstrated that follicle­stimulating hormone (FSH) could directly affect skeletal remodelling by stimulating the formation and the function of osteoclasts in vitro and in vivo. However, the effect of FSH on periapical bone loss remained to be fully elucidated. In the current study, a rat model was established in order to verify the effect of FSH in experimental periapical lesions. It was identified that FSH aggravated the bone loss of periapical lesions. In addition, RANKL­, TRAP­, TNF­α­ and IL­1ß­positive cells were increased significantly in FSH­treated groups, which indicated that the function of FSH in bone loss may be mediated through the increasing activity of osteoclasts and the increased secretion of inflammatory cytokines. The results of the current study suggested that FSH, independent of oestrogen, may aggravate periapical bone loss by FSH receptors, which may serve an important role in the immune and inflammatory response of the host to root canal and periradicular infection during menopause.

Rare Root Canal Configuration of Bilateral Maxillary Second Molar Using Cone-beam Computed Tomographic Scanning.

The aim of this article was to present a right maxillary second molar with an unusual root canal morphology of 4 roots and 5 canals as confirmed by cone-beam computed tomographic (CBCT) imaging. The tooth had a C-shaped mesiobuccal root (CBCT imaging revealed that the root was closer to the palate than the buccal side) with 2 canals, 2 fused distobuccal roots with 2 separate canals, and 1 normal bulky palatal root with 1 canal. After thoroughly examining the rare anatomy, root canal treatment was applied on the tooth. This article shows the complexity of maxillary second molar variation and shows the significance of CBCT imaging in the confirmation of the 3-dimensional anatomy of teeth and endodontic treatment.

[Raman spectroscopy study of the effect of H+ on the oxygen affinity capacity of hemoglobin].

The hemoglobin was extracted from the blood which was provided by the healthy volunteers and the impact of the pH on hemoglobin oxygen binding capacity was studied with microscopic Raman spectroscopy. The results indicated that: under the excitation light of 514.5 nm, with the reducing of the oxygen partial pressure (PO2), the Raman peak intensity at 1 375, 1 562, 1 585 and 1 638 cm(-1) of the control hemoglobin (pH 7.4) reduced gradually, among which, the change of the 1 375 and 1 638 cm(-1) were the most significant and had a good relevance with the PO2. The curves were plotted by regarding the PO2 as the x-axis and the Raman absolute intensity as the y-axis, and the relationship between hemoglobin Raman absolute intensity of the 1 375 and 1 638 cm(-1) and their related PO2 levels when the pH was 5.7, 7.4 and 8.0 respectively were analyzed. The data was well linear fitted and the fitting equation was obtained. The relationship of the slope (Raman intensity/PO2 level) among them were K8.0 > K7.4 > K5.7, indicating that the lower the pH, the easier the release of the oxygen molecules. It was showed that the Raman spectroscopy technique could be used to detect the oxygen binding rate of hemoglobin quantitatively, and the effect of the PH on oxygen binding state of hemoglobin could be observed, which could provide a new method and make a foundation for the monitoring of the PO2 levels in the blood, as well as the research on the regulatory factors of the blood oxygen affinity, such as H+ and CO2.

[Effects of indocyanine green on near-infrared optical properties and optical coherence tomographic image of cerebral blood vessel in vivo in rats].

The scope of this research lies in the effects of indocyanine green (ICG) on the near-infrared optical properties and optical coherence tomographic image of cerebral blood vessel in vivo in rats. The skulls of SD rats were opened under nembutal anesthesia to expose and mark the middle cerebral artery. The reflectance spectra of middle cerebral artery were monitored by Vis/ NIR spectrometer and the optical attenuation coefficients of middle cerebral artery were detected by optical coherence tomography (OCT) when indocyanine green was administrated intravenously through tail veins. It was shown that the reflectance spectra of middle cerebral artery could provide guidance for OCT image, where characteristic changes appeared around 800 nm, an absorption peak of indocyanine green. Additionally, significant difference (p<0.01) was observed between the optical attenuation coefficients of middle cerebral artery with and without indocyanine green, which were 24.692 +/- 1.471 and 15.088 +/- 1.602, respectively. It was concluded that indocyanine green, as an optical contrast agent to enhance detection of cerebral artery by the reflectance spectra and OCT imaging, has the potential for monitoring and imaging of cerebral blood vessels.