Stem Cells from Human Exfoliated Deciduous Teeth: Biology and Therapeutic Potential

Stem cells isolated from human exfoliated deciduous teeth (SHEDs) are a type of mesenchymal stem cells (MSCs), widely investigated for regenerative treatment. They are isolated from dental pulp tissues remaining in physiologically shedding human deciduous teeth. Thus, SHEDs are easy to access and not required invasive procedure to obtain cells. SHEDs are multipotent mesenchymal stem cells; however, they possess distinct properties when compared to other MSCs. In this regard, SHEDs exhibit higher proliferative rate than bone marrow‐derived MSCs and greater osteogenic differentiation potency than human dental pulp stem cells. This chapter reviews the isolation technique and basic characteristics of SHEDs. Moreover, the intracellular signalling involved in the stemness regulation and differentiation ability of SHEDs is discussed, particularly on fibroblast growth factor, Notch, and Wnt signalling. Finally, the potential regenerative therapeutic application of SHEDs is also described

Polycaprolactone-Based Biomaterials for Guided Tissue Regeneration Membrane

Guided tissue regeneration (GTR) is a clinical procedure promoting regeneration of periodontal tissues. In general, this technique provides spaces for periodontal cells to repopulate and regenerate in the periodontal defect by physically preventing an invasion of gingival tissues in the affected area. Although various reports certify clinical success of GTR, high variation of favourable outcome among studies leads to the investigation to improve clinical GTR efficiency for periodontal tissue regeneration. Recent development of GTR membrane aims to augment bioactivity for facilitating and enhancing tissue healing and regeneration. Various approaches are examined, for example, the release of growth factor, the incorporation of bioactive ceramics and the delivery of antimicrobial agents. Polycaprolactone (PCL) is widely used in biomedical application due to its acceptable biocompatibility and degradability. Physical characteristics are easy to manipulate. Various forms and shapes are simple to fabricate. PCL can be employed as GTR membrane and scaffold filling in the periodontal-defect area. Bioactive PCL could be fabricated by various techniques to enhance periodontal tissue regeneration. The present chapter reviews the bioactive approaches for GTR membrane, and the potential utilization of PCL for GTR application is described

Genetic and molecular basis of heavy metal tolerance and the heat shock response in the Mediterranean fruit fly : Ceratitis capitata

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995.Includes bibliographical references (leaves 171-187).Microfiche.xix, 187 leaves, bound ill. 29 cmThe Mediterranean fruit fly (Medfly), Ceratitis capitata, is a major pest of agricultural commodities world wide. Genetic and molecular studies of heavy metal tolerance and the heat shock response in the Medfly can provide a better understanding of how eukaryotes respond to environmental stresses. Potential uses of heavy metal tolerance and a heat shock gene in biological control programs have also been evaluated. Three heavy metal tolerant strains were established. Genetic analyses of test crosses between these strains and a nonselected strain suggested different modes of inheritance underlying the heavy metal tolerance trait. An attempt to generate a Y-autosome translocation involving this trait appeared to not be feasible. PCR products were amplified from the Medfly genome based on conserved domains of a metallothionein gene. Genomic DNA sequences homologous to these PCR products demonstrated coding potential metallothionein proteins, although transcripts homologous to these sequences were not detected in poly(A) selected RNA. This coding potential included a long open reading frame with a potentially cysteine rich region and alignment to mammalian metallothionein proteins. A heat shock like gene (Cerhscl) was cloned from the Medfly using PCR. This PCR used heavy metal induced cDNA as a template and a PCR primer designed from a conserved domain of metallothionein proteins. The Cerhscl gene shows some structural characteristics of a heat inducible gene including the presence of several heat shock elements and the absence of an intron. The Cerhsc1 gene also exhibits a heat shock response resulting in a 10 to 20% increase in the level of transcription. Developmentally, expression of the Cerhsc1 gene is very abundant in the adult stage, less so in the pupal stage and not detectable in the embryo stages. Overall, the Cerhsc1 gene exhibits structural and functional similarities to both heat inducible and non-heat inducible genes from a wide range of organisms

Microporous nanofibrous fibrin -based scaffolds for craniofacial bone tissue engineering

The fibrotic response of the body to synthetic polymers limits their success in tissue engineering and other applications. Though porous polymers have demonstrated improved healing, difficulty in controlling their pore sizes and pore interconnections has clouded the understanding of this phenomenon. In this study, a novel method to fabricate natural polymer/calcium phosphate composite scaffolds and immobilized alkaline phosphatase fibrin scaffolds with tightly controllable pore size, pore interconnection has been investigated. Microporous, nanofibrous fibrin scaffolds (FS) were fabricated using sphere-templating method. Calcium phosphate/fibrin composite scaffolds were created by solution deposition of calcium phosphate on fibrin surfaces or by direct incorporation of nanocrystalline hydroxyapatite (nHA). The SEM results showed that fibrin scaffolds exhibited a highly porous and interconnected structure. Osteoblast-like cells, obtained from murine calvaria, attached, spread and showed a polygonal morphology on the surface of the biomaterial. Multiple cell layers and fibrillar matrix deposition were observed. Moreover, cells seeded on mineralized fibrin scaffolds (MFS) exhibited significantly higher alkaline phosphatase activity as well as osteoblast marker gene expression compared to FS and nHA incorporated fibrin scaffolds (nHA/FS). These fibrin-based scaffolds were degraded both in vitro and in vivo. Furthermore, these scaffolds promoted bone formation in a mouse calvarial defect model and the bone formation was enhanced by addition of rhBMP-2. The second approach was to immobilize alkaline phosphatase (ALP) on fibrin scaffolds. ALP enzyme was covalently immobilized on the microporous nanofibrous fibrin scaffolds using 1-ethyl-3-(dimethylaminopropyl)carbodiimide hydrochloride (EDC). The SEM results demonstrated mineral deposition on immobilized ALP fibrin scaffolds (ALP/FS) when incubated in medium supplemented with β-glycerophosphate, suggesting that the immobilized ALP enzyme was active. Mineral deposition was also observed in cells seeded on immobilized ALP/FS. Furthermore, cells seeded on immobilized ALP/FS exhibited higher osteoblast marker gene expression compared to those on control FS. Upon implantation in mouse calvarial defect, the immobilized ALP/FS treated group had slightly higher bone volume in the defect compared to empty defect control and FS alone. In conclusion, the enhanced biological responses both in vitro and in vivo demonstrated the potential application of these novel microporous nanofibrous fibrin-based scaffolds for bone tissue engineering

Fluoride Concentration in Tap Water from Different Regions in Thailand: Konsentrasi Fluoride dalam Air Keran dari Berbagai Daerah di Thailand

Fluoride supplementation in drinking tap water is one of the well-known effective methods for dental caries prevention. However, overexposure to fluoride following excessive fluoride intake from drinking water leads to dental fluorosis. Therefore, the assessment of daily fluoride consumption is required to calculate the optimal fluoride intake. The present study investigated the fluoride concentration in tap water collected from different areas in Thailand. A total of 27 locations were selected. Three samples of tap water (500 mL each) were independently collected from one location. Each sample in the same location was collected from the same faucet of tap water and stored in different containers. The samples were collected by dental students or dentists who worked in the selected areas from March 2020 to June 2020. Briefly, the faucet was cleaned with the tap water and the water was run from the faucet for 1-2 mins. Then, water was collected in 500 mL bottles and immediately capped. Samples were then stored at room temperature in tightly sealed bottles until analysis. Findings showed that most samples contained fluoride at a concentration lower than 0.7 mg/mL. Further, the water pH was in the range of 6.81-8.37. These levels were lower than the cut-offs established by the World Health Organization (WHO) for maximum levels of fluoride and pH in drinking water. In conclusion, the present study demonstrated that fluoride levels in tap water from different regions in Thailand are lower than those recommended by WHO for fluoride levels in drinking water.

Regulation of osteoprotegerin expression by Notch signaling in human oral squamous cell carcinoma cell line

Objective: To investigate the influence of Notch signaling on osteoprotegerin (OPG) expression in a human oral squamous cell carcinoma cell line. Methods: Activation of Notch signaling was performed by seeding cells on Jagged1 immobilized surfaces. In other experiments, a γ-secretase inhibitor was added to the culture medium to inhibit intracellular Notch signaling. OPG mRNA and protein were determined by real-time PCR and ELISA, respectively. Finally, publicly available microarray database analysis was performed using connection up- or down-regulation expression analysis of microarrays software. Results: Jagged1-treatment of HSC-4 cells enhanced HES1 and HEY1 mRNA expression, confirming the intracellular activation of Notch signaling. OPG mRNA and protein levels were significantly suppressed upon Jagged1 treatment. Correspondingly, HSC-4 cells treated with a γ-secretase inhibitor resulted in a significant reduction of HES1 and HEY1 mRNA levels, and a marked increase in OPG protein expression was observed. These results implied that Notch signaling regulated OPG expression in HSC-4 cells. However, Jagged1 did not alter OPG expression in another human oral squamous cell carcinoma cell line (HSC-5) or a human head and neck squamous cell carcinoma cell line (HN22). Conclusions: Notch signaling regulated OPG expression in an HSC-4 cell line and this mechanism could be cell line specific

Draconarius Ovtchinnikov 1999

Draconarius Ovtchinnikov, 1999 Draconarius Ovtchinnikov 1999: 70. Type species by original designation, D. venustus Ovtchinnikov, 1999. Diagnosis. Members of the genus Draconarius resemble those of Asiacoelotes in having an elongated cymbial furrow, a long, slender embolus, and long, strongly convoluted spermathecae. Males can be distinguished by the presence of a dorsal apophysis on the conductor, females by the posteriorly originating copulatory ducts and widely separated spermathecae. The genus Draconarius is known from Tadzhikistan, Bhutan, Nepal, China, Korea and Thailand.Published as part of Dankittipakul, Pakawin, Chami-Kranon, Thanaphum & Wang, Xin-Ping, 2005, Amaurobiidae) from Thailand, pp. 1-11 in Zootaxa 970 on page 8, DOI: 10.5281/zenodo.17129

Coelotes suthepicus Dankittipakul, Chami-Kranon & Wang, 2005, sp. n.

Coelotes suthepicus sp. n. Figures 4–8 Type material. HOLOTYPE: ɗ (MHNG), THAILAND, Chiang Mai Province and District, Doi Suthep–Pui National Park, Doi Suthep, San Ku, 1600 m, evergreen hill forest, flight intercept trap, 8.– 12.XI. 2004, leg. S. Sonthichai & T. Chami­Kranon. PARATYPES: 3 Ψ (MHNG), from the type locality, 18.XI. 2004, leg. S. Sonthichai, T. Chami­Kranon & A. Hasalem. Diagnosis. Males of C. suthepicus sp. n. can be recognized by a short conductor and by the presence of a basal tooth on the conductor (Figs 4–6). Females are distinguished by strongly convoluted spermathecae and large, club­shaped anterior end of copulatory ducts (Fig. 8); their epigynes are provided with anteriorly notched atrium (Fig. 7). Coelotes suthepicus sp. n. resembles European species, C. atropos (Walckenaer, 1830) but it can be distinguished from this species and all other congeners by characters mentioned above. Etymology. The specific epithet refers to the type locality: suthepicus is a Latinized adjective of Suthep. Description. ɗ (holotype). Total length 10.71. Carapace 5.02 long, 3.28 wide. Eye sizes and interdistances: AME 0.18, ALE 0.20, PME 0.16, PLE 0.20; AME–AME 0.10, AME–ALE 0.10, PME–PME 0.19, PME–PLE 0.25, ALE–PLE 0.07; MOQ 0.58 long, front width 0.49, back width 0.52. Cheliceral groove with 3 promarginal and 3 or 4 retromarginal teeth. Leg formula 1423 (17.86, 16.21, 13.65, 13.20). Leg measurements: femora: I 4.20, II 4.00, III 3.61, IV 4.31; patellae: I 1.98, II 1.89, III 1.39, IV 1.56; tibiae: I 4.10, II 3.02, III 2.51, IV 3.93; metatarsi: I 4.56, II 3.53, III 3.50, IV 4.25; tarsi: I 3.02, II 2.21, III 2.19, IV 2.16. Male palp (Figs 4–6): patellar apophysis (PA) relatively large, slightly curved distally; RTA long, extending beyond distal margin of tibia; RDTA relatively broad, widely separated from the RTA; cymbial furrow short; conductor short, bifurcate, with basal tooth; conductor lamella indistinct; a dorsal apophysis on the conductor (DC) with round apex, longer than conductor (C) when seen in ventral view; embolus originating probasally; median apophysis (MA) large, strongly sclerotized. Ψ paratype. Total length 9.08. Carapace 4.55 long, 3.18 wide. Eye sizes and interdistances: AME 0.10, ALE 0.15, PME 0.15, PLE 0.15; AME–AME 0.13, AME–ALE 0.07, PME–PME 0.15, PME–PLE 0.17, ALE–PLE 0.08; MOQ 0.45 long, front width 0.34, back width 0.42. Cheliceral groove provided with 3 promarginal and 4 retromarginal teeth, respectively. Leg formula 4123 (12.69, 12.02, 10.69, 9.19). Leg measurements: femora: I 3.32, II 3.30, III 2.78, IV 3.58; patellae: I 0.91, II 0.89, III 0.90, IV 1.06; tibiae: I 3.22, II 2.58, III 2.08, IV 3.05; metatarsi: I 3.02, II 2.60, III 2.28, IV 3.35; tarsi: I 1.55, II 1.32, III 1.15, IV 1.65. Epigyne (Figs 7–8): epigynal hoods (H) located anterior to small, lateral epigynal teeth (ET). Internal structures with copulatory ducts (CD) anterior to the convoluted spermathecae situated close to each other; fertilization ducts (FD) simple, located posteriorly. Natural history. Coelotes suthepicus sp. n. inhabits evergreen hill forest at 1,600 m altitudes where it occurs together with D. anthonyi. The latter species appears to occupy a wider altitudinal range: it was also found between 1,500 m and 1,600 m near the summit of Doi Pui. The male holotype was collected by a flight intercept trap placed on the forest floor. The female paratypes were obtained from pitfall traps. Traps were set up form July 2004 to February 2005 but mature spiders were collected only in November. Specimens collected at soil banks along the road to the summit all belong to D. anthonyi. Distribution. Known only from the type locality.Published as part of Dankittipakul, Pakawin, Chami-Kranon, Thanaphum & Wang, Xin-Ping, 2005, Amaurobiidae) from Thailand, pp. 1-11 in Zootaxa 970 on pages 4-6, DOI: 10.5281/zenodo.17129