Activation of cellular antioxidative stress and migration activities by purified components from immortalized stem cells from human exfoliated deciduous teeth.

Although stem cell-based regenerative medicine has been extensively studied, it remains difficult to reconstruct three dimensional tissues and organs in combination with vascular systems in vitro. One clinically successful therapy is transplantation of mesenchymal stem cells (MSC) into patients with graft versus host disease. However, transplanted cells are immediately damaged and destroyed because of innate immune reactions provoked by thrombogenic inflammation, and patients need to take immunosuppressive drugs for the immunological regulation of allogeneic cells. This reduces the benefits of stem cell transplantation. Therefore, alternative therapies are more realistic options for clinical use. In this study, we aimed to take advantage of the therapeutic efficacy of MSC and use multiple cytokines released from MSC, that is, stem cells from human exfoliated deciduous teeth (SHEDs). Here, we purified components from conditioned media of immortalized SHED (IM-SHED-CM) and evaluated the activities of intracellular dehydrogenase, cell migration, and antioxidative stress by studying the cells. The immortalization of SHED could make the stable supply of CM possible. We found that the fractionated component of 50-100 kD from IM-SHED-CM had higher efficacy than the original IM-SHED-CM in terms of intracellular dehydrogenase and cell migration in which intracellular signal transduction was activated via receptor tyrosine kinases, and the glutathione peroxidase and reductase system was highly active. Although antioxidative stress activities in the fractionated component of 50-100 kD had slightly lower than that of original IM-SHE-CM, the fraction still had the activity. Thus, the use of fractionated components of 50-100 kD from IM-SHED-CM could be an alternative choice for MSC transplantation because the purified components from CM could maintain the effect of cytokines from SHED.

Clinical and radiographic success rate of the root canal filling materials used in primary teeth: A systematic review.

One of the most important factors that determine the success of pulpectomy in primary teeth is the root canal filling material used. This systematic review is an update on the success rates of various materials used for obturation in primary teeth. An electronic search was carried out in the PubMed, Scopus, Web of Science, and Cochrane Library databases with the preset inclusion and exclusion criteria. Only randomized or quasi-randomized clinical and controlled trials with a minimum follow-up of 12 months were included for analysis. Nine articles were considered potentially eligible for inclusion in this review. All the included trials had zinc oxide-eugenol (ZOE) cement as a control group. The time span of the included trials extended from 12 to 30 months. Only 2 trials were at low risk of bias. Evidence to support the success rates of obturating materials used in primary teeth is scarce, which necessitates further highquality randomized controlled clinical trials with regard to this issue.

OXIS contacts of primary molars: do they change over time?

PURPOSE: Although a series of studies on OXIS contacts have been performed, studies regarding changes in OXIS contacts over time are lacking. Therefore, this study aimed to evaluate the change in contact type between primary molars after 3 years in children aged 3-7 years. METHODS: This longitudinal study was conducted using 2922 sectional die models of 926 children. At baseline (T0), the contact type between the primary molars was scored using replication via the sectional die model method according to the OXIS criteria. After 3 years, the sectional die models of the same children were scored using the same criteria (T1). RESULTS: McNemar's tests revealed a significant change in contacts from baseline to 3 years. The post hoc test explained specific changes in the contacts that were observed to be significant. These were O to X (p < 0.001), O to I (p < 0.001), O to S (p = 0.035), and I to X (p < 0.001). CONCLUSIONS: A significant change in OXIS contact over time was observed. The O-type contact underwent the maximum change. The least and most stable contacts are the "O" and "I" types, respectively. This change in contact type with age may alter the risk of caries in children.

[Prevalence of exogenous pigmentations and caries by intake of ferric supplements in primary dentition]. / Prevalencia de pigmentaciones exógenas y caries por ingesta de suplementos férricos en dentición primaria.

Objective: The aim of this study was to determine the prevalence of extrinsic black pigmentation in primary dentition and its relationship with dental caries in children aged 3 to 5 years. Materials and methods: The study design was descriptive, prospective, cross-sectional and observational; The sample of the present study consisted of 79 children who were receiving treatment with ferrous sulfate, who underwent a clinical examination and odontogram. To determine the presence of extrinsic black pigmentation, the Shourie classification was used. Results: A low prevalence of extrinsic pigmentation of 7.6% was found, and children with extrinsic pigmentation had a Ceod of 9.83+-3.601, while those children without the presence of pigmentations had a Ceod of 4.60+-3.248. Conclusions: A significant relationship was found between the Ceod index and extrinsic black pigmentation (p<0.001).

Effect of silver diamine fluoride combined with photodynamic therapy on primary enamel microhardness.

OBJECTIVES: This study aimed to assess the effect of silver diamine fluoride (SDF) combined with photodynamic therapy (PDT) on primary enamel microhardness. MATERIALS AND METHODS: This in vitro, experimental study was conducted on 40 extracted primary molars with sound buccal/lingual surfaces. The baseline enamel microhardness of the teeth was initially measured by a Vickers hardness tester. Next, the teeth were randomly assigned to four groups (n=10) for treatment with SDF, PDT, SDF plus PDT, and control (no intervention). After the intervention, the teeth underwent a 14-day pH-cycling, and enamel microhardness was measured again. The change in microhardness was calculated for each group, and comparisons were made by two-way ANOVA and t-test (alpha=0.05). RESULTS: The mean secondary microhardness of the three intervention groups was significantly higher than that of the control group (P<0.05). Despite slightly higher microhardness in SDF + PDT group, followed by the SDF group, the difference in secondary microhardness was not significant among the three intervention groups (P>0.05). CONCLUSION: Treatment of primary enamel with SDF or PDT can increase its microhardness and enhance remineralization. However, combined use of SDF and PDT had no additional advantage over the use of SDF alone.

Research on NiTi instruments combined with ultrasonic irrigation and multiantibiotic paste in root canal therapy of periapical inflammation in deciduous teeth.

Pain often occurs after root canal treatment due to unavoidable mechanical or chemical damage. The purpose of the present study was to investigate the efficacy of a nickel-titanium (NiTi) device combined with ultrasonic irrigation and multiple antibiotic creams in the treatment of periapical inflammation of deciduous teeth, so as to improve the understanding of root canal treatment and optimize clinical practice. Evaluation of efficacy was conducted using X-rays and the Visual Analog Scale. This treatment significantly reduced pain and also improved patient compliance and treatment outcomes. The findings of the present study may have scientific and clinical significance for optimizing root canal treatment in pediatric dentistry and requires further in-depth research in clinical practice. These outcomes may provide potential new ideas and directions for improving patients' quality of life and the efficacy of clinical treatment and have further impacts on future related research and medical practice.

Antimicrobial Efficacy of Saline, Chlorhexidine, and Zataria Multiflora and Mentha Piperita Essential Oils in Root Canal Irrigation of Primary Molars.

Objectives: This study aimed to compare the antimicrobial efficacy of saline, 0.5% and 2% Zataria multiflora (Z. multiflora) essential oil, 0.5% and 2% Mentha piperita (M. piperita) essential oil, and 0.2% chlorhexidine (CHX) as root canal irrigants for primary molar teeth. Materials and Methods: A total of 64 primary molars were used in this in vitro study. The teeth were randomly assigned to six groups (N=10). The root canals were prepared up to file #35, and all teeth were sterilized before contamination with Enterococcus faecalis (E. faecalis; ATCC 29212) suspension. After 48 hours of incubation, the root canals in each group were irrigated with the respective irrigants. Sterile paper points were then used to collect microbial samples from the root canals. A colony counter was used to count the number of colony-forming units (CFUs). Data were analyzed by SPSS version 20 (alpha=0.05). Results: The colony count was significantly different among the groups (P<0.001), and 2% M. piperita (P=0.009), 0.5% Z. multiflora (P=0.021), and 0.2% CHX (P=0.002) were significantly more effective than saline in elimination of E. faecalis. The ascending order of microbial count after irrigation was as follows: saline > 0.5% M. piperita > 0.2% CHX > 2% M. piperita > 0.5% Z. multiflora. Conclusion: The current study showed the optimal antibacterial activity of 0.5% Z. multiflora essential oil and 2% M. piperita essential oil against E. faecalis, and indicated their possible efficacy for use as an irrigant for root canal irrigation of primary molars.

Effect of α7 nAChR-autophagy axis of deciduous tooth pulp stem cells in regulating IL-1ß in the process of physiological root resorption of deciduous teeth.

Physiological root resorption of deciduous teeth is a normal phenomenon occurring during the developmental stages of children. Previous research has indicated the pivotal role of the inflammatory microenvironment in this process, although the specific mechanisms remain unclear. This study is aimed at elucidating the involvement of the alpha7 nicotinic acetylcholine receptors (α7 nAChR)-autophagy axis in the regulation of the inflammatory microenvironment during physiological root resorption in deciduous teeth. Samples were collected from deciduous teeth at various stages of physiological root resorption, and deciduous dental pulp stem cells (DDPSCs) were isolated and cultured during the mid-phase of root resorption. The findings revealed a substantial infiltration of the pulp of deciduous teeth at the mid-phase of root resorption, characterized by elevated expression levels of α7 nAChR and IL-1ß. Significantly increased IL-1ß and α7 nAChR expressions were observed in DDPSCs during the mid-phase of root resorption, with α7 nAChR demonstrating a regulatory effect on IL-1ß. Moreover, evidence suggested that mechanical stress may act as a trigger, regulating autophagy and IL-1 expression via α7 nAChR. In conclusion, mechanical stress was identified as a regulator of autophagy in DDPSCs through α7 nAChR, influencing the expression of IL-1ß and contributing to the formation of the inflammatory microenvironment. This mechanism plays a crucial role in the physiological root resorption of deciduous teeth. KEY MESSAGES: The pulp of deciduous teeth at mid-phase of root resorption was heavily infiltrated with high expression of α7nAChR and IL-1ß. α7 nAChR acts as an initiating factor to regulate IL-1ß through autophagy in DDPSCs. Mechanical stress can regulate autophagy of DDPSCs through α7 nAChR and thus affect IL-1ß expression and inflammatory microenvironment formation in physiological root resorption in deciduous teeth.

Unveiling an Uncommon Scenario of Co-occurrence of Multiple Odontomes With Impacted Maxillary Lateral Incisor and Canine in a 17-Year-Old Girl: A Unique and Rare Case Report.

This case report presents the enigma of multiple odontomes with overretained deciduous teeth leading to the impaction of permanent successors (22, 23) in an abnormal position in a 17-year-old female patient who reported the chief complaint of maligned teeth. Permanent maxillary canines and lateral incisors are the most common teeth to face the brunt of impaction due to a wide range of etiological factors. It is imperative for a clinician to diagnose cases at an early stage to accelerate the rate of eruption of such teeth. This is especially important in cases where initially the etiology seems to be simple but on careful and judicious evaluation of the case, numerous other etiologies are found to map together for the underlying pathology. This case discusses how the presence of multiple odontomes with delayed exfoliation of deciduous teeth leads to the impaction of a permanent successor. Understanding the underlying pathology is seemingly important to devise intricate treatment mechanics for traction of impacted teeth without taxing anchorage from dental units and taking cognizance of the amount of alveolar bone loss post-removal of multiple odontomes. The appropriate thickness of alveolar bone scaffolding is required for the canine to extrude down, with an adequate band of marginal gingiva encircling the cement-enamel junction of the impacted canine, preventing any kind of fenestration and dehiscence. Hence, meticulous care was taken during surgical exposure and removal of odontomes to preserve an adequate labial cortical plate intact for traction. These excavated tooth-like structures were later subjected to histopathological evaluation, which confirmed the diagnosis of compound odontomes.

Enhancing Proliferation of Stem Cells from Human Exfoliated Deciduous Teeth (SHED) through hTERT Expression while Preserving Stemness and Multipotency.

BACKGROUND: Stem cells from human exfoliated deciduous teeth (SHED) hold promise in regenerative medicine owing to their multipotent capabilities resembling mesenchymal stem cells (MSCs). Despite their potential, SHED have not been extensively investigated because their limited lifespan and unavailability of cell-lines pose challenges for therapeutic applications. This study investigated the effect of ectopic human telomerase reverse transcriptase (hTERT) expression on SHEDs' proliferation while preserving stemness and genomic integrity. METHODS: Deciduous teeth were collected from children aged 6-10 years. After isolation and characterization, the SHED were transduced with pBabe-puro-hTERT retrovirus to establish SHED cell-line, which was evaluated and compared with pBabe-puro (mock control) for stemness, multipotency and growth attributes through flow cytometry, trilineage differentiation, and growth kinetics. We also estimated hTERT gene expression, genomic integrity, and validated cell-line through STR analysis. RESULTS: Following hTERT transduction, SHED displayed elevated hTERT gene expression while retaining fibroblast-like morphology and mesenchymal stem cell markers. Moreover, after hTERT transduction cellular shape remained same along with increased replicative lifespan and proliferation potential. SHED-hTERT cells exhibited multi-potency and maintained stemness, as evidenced by surface marker expression and multilineage differentiation. Furthermore, genomic integrity was not affected by hTERT integration, as confirmed by STR analysis and CDKN2A gene assessment. CONCLUSION: Ectopic hTERT expression in SHED successfully prolonged their replicative lifespan and improved their ability to proliferate and migrate, while preserving their stemness, multipotency and genomic integrity, suggesting minimal carcinogenic risk. Establishment of SHED cell-line holds potential in regenerative medicine applications, especially in cell-based drugs and tissue engineering experiments.

Comparison of Endoflas and Zinc Oxide Eugenol as Root Canal Filling Materials for Pulpectomy in Deciduous Teeth: a Systematic Review and Meta-Analysis.

Objectives: To evaluate and compare the effectiveness of Endoflas and Zinc Oxide Eugenol (ZOE) as root canal filling materials (RCFMs) for the pulpectomy of deciduous teeth by analyzing multiple clinical and radiographic success and failure follow-ups in previously published studies. Data: All clinical studies that investigated the pulpectomy of the deciduous teeth of children aged 3-9 years. Sources: The databases used for source identification included MEDLINE (via PubMed), Scopus, Web of Science, and the Cochrane Library. No limitations were imposed on the publication year or language. The selection of studies and extraction of relevant study characteristics were conducted from December 26, 2021, to September 7, 2023. Additionally, the risk of bias (RoB) in the included studies was evaluated by using a RoB instrument (RoB 2). Eligible studies were then combined, and a random-effects model was applied by using the maximum likelihood estimations of log risk ratios and their corresponding 95% confidence intervals. Study selection: Of the 3913 records found in the abovementioned databases, nine were eligible for systematic review and eight were eligible for meta-analysis. The studies included 628 pulpectomies of deciduous molar teeth in children. The overall results showed that compared with Endoflas, ZOE was associated with a higher risk ratio for clinical evaluation (LOG[RR] = 0.06, CI 0.03-0.09, p-value 0.001) and radiographic evaluation (LOG[RR] = 0.68, CI 0.35-1.00, p-value 0.001). This association was highly significant at 6- and 9-month follow-ups. Conclusion: Compared with ZOE, Endoflas was associated with a lower risk of the clinical and radiographic failure of deciduous teeth pulpectomy and a 6%-6.8% higher risk ratio, especially at 6- and 9-month follow-ups. Clinical significance: This study suggests the superiority of Endoflas over ZOE as an RCFM for deciduous teeth.

Frequency and variability of nonmetric dental crown traits of primary and permanent molars in a group of orthodontic patients.

BACKGROUND: The present study aimed to assess the frequency and variation of 13 nonmetric dental crown traits (NDCT) in permanent and primary molars in German orthodontic patients. METHODS: Dental records from orthodontic patients were screened and evaluated. First and second permanent and primary upper and lower molars (from left and right sides) were assessed. Teeth with cavitated dental caries, occlusal wear, restorations and obvious dental deformities were not evaluated. The NDCT for permanent molars were identified and scored according to the odontoscopic system developed by Arizona State University Dental Anthropology System (ASUDAS). The NDCT for primary molars were identified and scored according to ASUDAS, Hanihara's method and Sciulli's method. The χ2 test was used to investigate side preference and sexual dimorphism at a significance level of p ≤ 0.050. RESULTS: A total of 163 orthodontic patients (82 males and 81 females) aged 8-14 years were included. A sexual dimorphism was observed for the hypocone in first upper permanent molar (p = 0.041). The protostylid was observed in lower permanent molars (range 2.1-10%). Males presented more hypoconulid than females (p = 0.019). Only females presented the distal trigonid crest in lower first permanent molars (p = 0.002). The most common groove pattern in primary molars was Y; male presented more Y grade than females in the lower second primary molar (p = 0.039). Asymmetry was observed in some traits, ranging from 0 to 100%. CONCLUSION: The present study showed the frequency of NDCT of molars in German orthodontic patients and demonstrated that some traits present sexual dimorphism.

Cartilage-Specific Gene Expression and Extracellular Matrix Deposition in the Course of Mesenchymal Stromal Cell Chondrogenic Differentiation in 3D Spheroid Culture.

Articular cartilage damage still remains a major problem in orthopedical surgery. The development of tissue engineering techniques such as autologous chondrocyte implantation is a promising way to improve clinical outcomes. On the other hand, the clinical application of autologous chondrocytes has considerable limitations. Mesenchymal stromal cells (MSCs) from various tissues have been shown to possess chondrogenic differentiation potential, although to different degrees. In the present study, we assessed the alterations in chondrogenesis-related gene transcription rates and extracellular matrix deposition levels before and after the chondrogenic differentiation of MSCs in a 3D spheroid culture. MSCs were obtained from three different tissues: umbilical cord Wharton's jelly (WJMSC-Wharton's jelly mesenchymal stromal cells), adipose tissue (ATMSC-adipose tissue mesenchymal stromal cells), and the dental pulp of deciduous teeth (SHEDs-stem cells from human exfoliated deciduous teeth). Monolayer MSC cultures served as baseline controls. Newly formed 3D spheroids composed of MSCs previously grown in 2D cultures were precultured for 2 days in growth medium, and then, chondrogenic differentiation was induced by maintaining them in the TGF-ß1-containing medium for 21 days. Among the MSC types studied, WJMSCs showed the most similarities with primary chondrocytes in terms of the upregulation of cartilage-specific gene expression. Interestingly, such upregulation occurred to some extent in all 3D spheroids, even prior to the addition of TGF-ß1. These results confirm that the potential of Wharton's jelly is on par with adipose tissue as a valuable cell source for cartilage engineering applications as well as for the treatment of osteoarthritis. The 3D spheroid environment on its own acts as a trigger for the chondrogenic differentiation of MSCs.

Union between deciduous and permanent as intrusive luxation sequelae: A case report.

Traumatic dental injuries (TDI) are common in children due learning to walk and lack of balance that leads to falls. Luxation is the trauma that occurs most frequently in the deciduous, being that the intrusive and the avulsive are the ones that cause more damage to the permanent successors. The potential to cause disturbances to the developing permanent germ is high due to anatomical proximity and depends on age, direction of intrusion, severity and treatment. The consequences to the permanent range from hypocalcifications of enamel to retention of the permanent germ. In this case, the developmental disturbance of the tooth 21 presenting with acute dentoalveolar abscess was a result of a three-degree intrusive luxation of the deciduous predecessor. The tooth 61 was misdiagnosed initially as avulsion, but it was a total intrusion as uncovered after a radiographic examination that showed an image suggestive of the presence of the deciduous tooth. The deciduous was extracted along with his permanent successor through outpatient procedure under antibiotic coverage and local anesthesia. The macro and microscopic analysis of the piece evidenced the presence of elements 21 and 61 closely united, as well as alterations provoked in both. There was remission of the infectious process and after 7 days it was verified the correct healing of the surgical wound. The radical outcome of this case emphasizes the relevance of appropriate clinical support as soon as possible in all TDI.

Coordination of water use strategies and leaf economic traits in coexisting exotic and native woody species from evergreen and deciduous broadleaf forests.

The leaf economics spectrum (LES) describes the covariation of traits relevant for carbon and nutrient economy in different plant species. However, much less is known about the correlation of LES with leaf water economy, not only because some woody species do not follow the rules, but also because they are rarely tested on the widespread, non-native, fast-growing trees. We hypothesized that fast-growing exotic species that spread on the fast side of the LES coordinate their water-use strategies (WUS) to maintain rapid growth, and that the pattern of coordination differs between evergreen and deciduous forests. Using 4 exotic and 4 native species from evergreen and deciduous broadleaf forests in China, we measured 17 traits of LES and WUS and analyzed their functional roles in different species groups. Our results suggest that LES plays a more important role in the coexistence of species within a community, while WUS contributes more to the distribution of species across different regions. The multidimensional coordination of LES and WUS could better explain the growth and distribution of different plant species and shed light on the coexistence of species from different forest types, especially fast-growing woody exotics.

Effect of Altitude Gradients on the Spatial Distribution Mechanism of Soil Bacteria in Temperate Deciduous Broad-Leaved Forests.

Soil bacteria are an important part of the forest ecosystem, and they play a crucial role in driving energy flow and material circulation. Currently, many uncertainties remain about how the composition and distribution patterns of bacterial communities change along altitude gradients, especially in forest ecosystems with strong altitude gradients in climate, vegetation, and soil properties. Based on dynamic site monitoring of the Baiyun Mountain Forest National Park (33°38'-33°42' N, 111°47'-111°51' E), this study used Illumina technology to sequence 120 soil samples at the site and explored the spatial distribution mechanisms and ecological processes of soil bacteria under different altitude gradients. Our results showed that the composition of soil bacterial communities varied significantly between different altitude gradients, affecting soil bacterial community building by influencing the balance between deterministic and stochastic processes; in addition, bacterial communities exhibited broader ecological niche widths and a greater degree of stochasticity under low-altitude conditions, implying that, at lower altitudes, community assembly is predominantly influenced by stochastic processes. Light was the dominant environmental factor that influenced variation in the entire bacterial community as well as other taxa across different altitude gradients. Moreover, changes in the altitude gradient could cause significant differences in the diversity and community composition of bacterial taxa. Our study revealed significant differences in bacterial community composition in the soil under different altitude gradients. The bacterial communities at low elevation gradients were mainly controlled by stochasticity processes, and bacterial community assembly was strongly influenced by deterministic processes at middle altitudes. Furthermore, light was an important environmental factor that affects differences. This study revealed that the change of altitude gradient had an important effect on the development of the soil bacterial community and provided a theoretical basis for the sustainable development and management of soil bacteria.

Disaggregation of canopy photosynthesis among tree species in a mixed broadleaf forest.

Carbon dioxide sequestration from the atmosphere is commonly assessed using the eddy covariance method. Its net flux signal can be decomposed into gross primary production and ecosystem respiration components, but these have seldom been tested against independent methods. In addition, eddy covariance lacks the ability to partition carbon sequestration among individual trees or species within mixed forests. Therefore, we compared gross primary production from eddy covariance versus an independent method based on sap flow and water-use efficiency, as measured by the tissue heat balance method and δ13C of phloem contents, respectively. The latter measurements were conducted on individual trees throughout a growing season in a mixed broadleaf forest dominated by three tree species, namely English oak, narrow-leaved ash and common hornbeam (Quercus robur L., Fraxinus angustifolia Vahl, and Carpinus betulus L., respectively). In this context, we applied an alternative ecophysiological method aimed at verifying the accuracy of a state-of-the-art eddy covariance system while also offering a solution to the partitioning problem. We observed strong agreement in the ecosystem gross primary production estimates (R2 = 0.56; P < 0.0001), with correlation being especially high and nearly on the 1:1 line in the period before the end of July (R2 = 0.85; P < 0.0001). After this period, the estimates of gross primary production began to diverge. Possible reasons for the divergence are discussed, focusing especially on phenology and the limitation of the isotopic data. English oak showed the highest per-tree daily photosynthetic rates among tree species, but the smaller, more abundant common hornbeam contributed most to the stand-level summation, especially early in the spring. These findings provide a rigorous test of the methods and the species-level photosynthesis offers avenues for enhancing forest management aimed at carbon sequestration.

Seasonal variations of leaf ecophysiological traits and strategies of co-occurring evergreen and deciduous trees in white oak forest in the central Himalaya.

The present study investigates the seasonal variations in leaf ecophysiological traits and strategies employed by co-occurring evergreen and deciduous tree species within a white oak forest (Quercus leucotrichophora A. Camus) ecosystem in the central Himalaya. Seasonal variations in physiological, morphological, and chemical traits were observed from leaf initiation until senescence in co-occurring deciduous and evergreen tree species. We compared various parameters, including net photosynthetic capacity (Aarea and Amass), leaf stomatal conductance (gswarea and gswmass), transpiration rate (Earea and Emass), specific leaf area (SLA), mid-day water potential (Ψmd), leaf nitrogen (N) and phosphorus (P) concentration, leaf total chlorophyll concentration, photosynthetic nitrogen- and phosphorus-use efficiency (PNUE and PPUE), and water use efficiency (WUE) across four evergreen and four deciduous tree species. Our findings reveal that evergreen and deciduous trees exhibit divergent strategies in coping with seasonal changes, which are crucial for their survival and growth. Deciduous trees consistently exhibited significantly higher photosynthetic rates, transpiration rates, mass-based N and P concentrations (Nmass and Pmass), mass-based chlorophyll concentration (Chlmass), SLA, and leaf Ψmd, while maintaining lower leaf structural investments throughout the year compared to evergreen trees. These findings indicate that deciduous trees achieve greater assimilation rates per unit mass and higher nutrient-use efficiency. Physiological, morphological, and leaf N and P concentrations were higher in the summer (fully expanded leaf) than in the fall (senesced leaf). These insights provide valuable contributions to our understanding of tree species coexistence and their ecological roles in temperate forest ecosystems, with implications for forest management and conservation in the Himalayan region.

Arbuscular mycorrhizal fungal diversity and potential association networks among African tropical forest trees.

Tropical forests represent one of the most diverse and productive ecosystems on Earth. High productivity is sustained by efficient and rapid cycling of nutrients, which is in large part made possible by symbiotic associations between plants and mycorrhizal fungi. In these associations, an individual plant typically associates simultaneously with multiple fungi and the fungi associate with multiple plants, creating complex networks among fungi and plants. However, there are few studies that have investigated mycorrhizal fungal composition and diversity in tropical forest trees, particularly in Africa, or that assessed the structure of the network of associations among fungi and trees. In this study, we collected root and soil samples from Ise Forest Reserve (Southwest Nigeria) and used a metabarcoding approach to identify the dominant arbuscular mycorrhizal (AM) fungal taxa in the soil and associating with ten co-occurring tree species to assess variation in AM communities. Network analysis was used to elucidate the architecture of the network of associations between fungi and tree species. A total of 194 Operational Taxonomic Units (OTUs) belonging to six AM fungal families were identified, with 68% of all OTUs belonging to Glomeraceae. While AM fungal diversity did not differ among tree species, AM fungal community composition did. Network analyses showed that the network of associations was not significantly nested and showed a relatively low level of specialization (H2 = 0.43) and modularity (M = 0.44). We conclude that, although there were some differences in AM fungal community composition, the studied tree species associate with a large number of AM fungi. Similarly, most AM fungi had great host breadth and were detected in most tree species, thereby potentially working as interaction network hubs.

Biomimetic pulp scaffolds prepared from extracellular matrix derived from stem cells from human exfoliated deciduous teeth promote pulp-dentine complex regeneration.

AIM: To evaluate the role of biomimetic pulp scaffolds derived from the extracellular matrix derived of stem cells from human exfoliated deciduous teeth (SHED-ECM-PS) in promoting pulp-dentine complex regeneration. METHODOLOGY: SHED-ECM-PS was prepared through cell aggregation and decellularization techniques. Histological and immunofluorescence analyses, scanning electron microscopy, and DNA quantification assays were used to characterize the SHED-ECM-PS. Additionally, a tooth slice implantation model was established to evaluate the effects of SHED-ECM-PS on regeneration of the pulp-dentine complex in vivo. Extraction medium for SHED-ECM-PS was prepared, and its effect on bone marrow mesenchymal stem cells (BMMSCs) was assessed in vitro. Cell counting kit-8 and Ki-67 staining assays were performed to determine cell proliferation. The rate of apoptosis was evaluated by flow cytometry. Wound healing and transwell assays were conducted to evaluate cell migration. Alizarin red S staining was performed to examine mineralized nodule formation. Western blotting was used to detect the expression of osteogenic and odontogenic markers. The results were analysed using an independent two-tailed Student's t-test. p < .05 was considered statistically significant. RESULTS: SHED-ECM-PS was successfully constructed, exhibiting a striped dental pulp-like shape devoid of nuclear structures or DNA components, and rich in fibronectin, collagen I, DMP1 and DSPP. Notably, SHED-ECM-PS showed no impact on the proliferation or apoptosis of BMMSCs. Histological analysis revealed that dental pulp fibroblasts formed an interwoven mesh in the root canal, and angiogenesis was observed in the SHED-ECM-PS group. Moreover, a continuous, newly formed tubular dentine layer with polarized odontoblast-like cells was observed along the inner wall of the root canal. SHED-ECM-PS promoted the migration, polar alignment and mineralized nodule formation of BMMSCs and specifically elevated the expression levels of odontogenic markers, but not osteogenic markers, compared with the control group in vitro. CONCLUSION: SHED-ECM-PS exhibited no cytotoxicity and promoted pulp-dentine complex regeneration in vivo as well as cell migration and odontogenic differentiation of BMMSCs in vitro. These findings provide evidence that SHED-ECM-PS, as a novel biological scaffold, has the potential to improve the outcomes of REPs.