New Molecules of Diterpene Origin with Inhibitory Properties toward α-Glucosidase.

The incidence of diabetes mellitus (DM), one of the most common chronic metabolic disorders, has increased dramatically over the past decade and has resulted in higher rates of morbidity and mortality worldwide. The enzyme, α-Glucosidase (α-GLy), is considered a therapeutic target for the treatment of type 2 DM. Herein, we synthesized arylidene, heterocyclic, cyanoetoxy- and propargylated derivatives of quinopimaric acid (levopimaric acid diene adduct with p-benzoquinone) 1-50 and, first, evaluated their ability to inhibit α-GLy. Among the tested compounds, quinopimaric acid 1, 2,3-dihydroquinopimaric acid 8 and its amide and heterocyclic derivatives 9, 30, 33, 39, 44, with IC50 values of 35.57-65.98 µM, emerged as being good inhibitors of α-GLy. Arylidene 1ß-hydroxy and 1ß,13α-epoxy methyl dihydroquinopimarate derivatives 6, 7, 26-29, thiadiazole 32, 1a,4a-dehydroquinopimaric acid 40 and its indole, nitrile and propargyl hybrids 35-38, 42, 45, 48, and 50 showed excellent inhibitory activities. The most active compounds 38, 45, 48, and 50 displayed IC50 values of 0.15 to 0.68 µM, being 1206 to 266 more active than acarbose (IC50 of 181.02 µM). Kinetic analysis revealed the most active diterpene indole with an alkyne substituent 45 as a competitive inhibitor with Ki of 50.45 µM. Molecular modeling supported this finding and suggested that the indole core plays a key role in the binding. Compound 45 also has favorable pharmacokinetic and safety properties, according to the computational ADMET profiling. The results suggested that quinopimaric acid derivatives should be considered as potential candidates for novel alternative therapies in the treatment of type 2 diabetes.

Effects of career development learning on students' perceived employability: a longitudinal study.

This study investigates the relationship between career development learning (CDL) and students' perceived employability (SPE) with the mediating role of human capital. Using a quantitative method based on structured questionnaires to collect data from 512 Vietnamese students before starting their internship at businesses and 322 of them after 4 months, the results of the partial least square Structural Equational Model analysis showed that CDL positively affects SPE over time. Besides, the study explored the mediating effect of human capital in the relationship between CDL and SPE. In particular, scholastic capital and cultural capital play mediating roles while social capital failed to be in the relationship between CDL and SPE. This study is expected to enrich current literature on students' employability and human capital theory. From practical aspects, the findings of this work can be of benefit to higher education institutions in supporting their students to enhance their employability in labour market.

Acceptance and willingness to pay for COVID-19 vaccines among pregnant women in Vietnam.

OBJECTIVES: The aim of this study was to assess acceptance of COVID-19 vaccination and the willingness to pay (WTP) for it, and investigate associated factors among pregnant women in Vietnam. METHODS: Cross-sectional survey of pregnant women in two obstetric hospitals in Hanoi and Ca Mau provinces, Vietnam. Data on acceptance and WTP for COVID-19, demographic characteristics, maternal characteristics, and risk perceptions toward COVID-19 were collected. Multivariate logistic and linear regression models were performed to identify factors associated with the acceptance and WTP for the vaccine. RESULTS: Of 651 pregnant women, 60.4% accepted to receive the vaccine, and 82.6% of the total pregnant women were willing to pay for a COVID-19 vaccine with the mean amount of WTP of USD 15.2 (SD ± 27.4). The most common reason for refusing vaccination was "Worry about the safety of the vaccine" (66.9%) in Hanoi and "The preventive effect of COVID-19 is low" (45.2%) in Ca Mau. A higher income, having children, self-perceived risk of COVID-19 infection, and perceived risk to friends were associated with a higher likelihood of acceptance and WTP for the vaccine. CONCLUSIONS: Implementing COVID-19 vaccination and resource mobilisation among pregnant women in Vietnam is feasible, although communication programmes to improve risk perception and awareness about vaccine should be developed for facilitating acceptance of the vaccine.

BMP-2/ß-TCP Local Delivery for Bone Regeneration in MRONJ-Like Mouse Model.

Medication-related osteonecrosis of the jaw (MRONJ) is a severe pathological condition associated mainly with the long-term administration of bone resorption inhibitors, which are known to induce suppression of osteoclast activity and bone remodeling. Bone Morphogenetic Protein (BMP)-2 is known to be a strong inducer of bone remodeling, by directly regulating osteoblast differentiation and osteoclast activity. This study aimed to evaluate the effects of BMP-2 adsorbed onto beta-tricalcium phosphate (ß-TCP), which is an osteoinductive bioceramic material and allows space retention, on the prevention and treatment of MRONJ in mice. Tooth extraction was performed after 3 weeks of zoledronate (ZA) and cyclophosphamide (CY) administration. For prevention studies, BMP-2/ß-TCP was transplanted immediately after tooth extraction, and the mice were administered ZA and CY for an additional 4 weeks. The results showed that while the tooth extraction socket was mainly filled with a sparse tissue in the control group, bone formation was observed at the apex of the tooth extraction socket and was filled with a dense connective tissue rich in cellular components in the BMP-2/ß-TCP transplanted group. For treatment studies, BMP-2/ß-TCP was transplanted 2 weeks after tooth extraction, and bone formation was followed up for the subsequent 4 weeks under ZA and CY suspension. The results showed that although the tooth extraction socket was mainly filled with soft tissue in the control group, transplantation of BMP-2/ß-TCP could significantly accelerate bone formation, as shown by immunohistochemical analysis for osteopontin, and reduce the bone necrosis in tooth extraction sockets. These data suggest that the combination of BMP-2/ß-TCP could become a suitable therapy for the management of MRONJ.

Aging-Affected MSC Functions and Severity of Periodontal Tissue Destruction in a Ligature-Induced Mouse Periodontitis Model.

Mesenchymal stem cells (MSCs) are known to play important roles in the repair of lost or damaged tissues and immunotolerance. On the other hand, aging is known to impair MSC function. However, little is currently known about how aged MSCs affect the host response to the local inflammatory condition and tissue deterioration in periodontitis, which is a progressive destructive disease of the periodontal tissue potentially leading to multiple tooth loss. In this study, we examined the relationship between aging-induced impairment of MSC function and the severity of periodontal tissue destruction associated with the decrease in host immunomodulatory response using a ligature-induced periodontitis model in young and aged mice. The results of micro computerized tomography (micro-CT) and histological analysis revealed a more severe bone loss associated with increased osteoclast activity in aged (50-week-old) mice compared to young (5-week-old) mice. Immunostaining analysis revealed that, in aged mice, the accumulation of inflammatory T and B cells was higher, whereas the percentage of platelet-derived growth factor receptor α (PDGFRα)+ MSCs, which are known to modulate the apoptosis of T cells, was significantly lower than in young mice. In vitro analysis of MSC function showed that the expression of surface antigen markers for MSCs (Sca-1, CD90, CD146), colony formation, migration, and osteogenic differentiation of aged MSCs were significantly declined compared to those of young MSCs. Moreover, a significantly higher proportion of aged MSCs were positive for the senescence-associated ß galactosidase activity. Importantly, aged MSCs presented a decreased expression of FAS-L, which was associated with a lower immunomodulatory property of aged MSCs to induce T cell apoptosis in co-cultures compared with young MSCs. In summary, this is the first study showing that aging-induced impairment of MSC function, including immunomodulatory response, is potentially correlated with progressive periodontal tissue deterioration.

Type XVIII Collagen Modulates Keratohyalin Granule Formation and Keratinization in Oral Mucosa.

Epithelial keratinization involves complex cellular modifications that provide protection against pathogens and chemical and mechanical injuries. In the oral cavity, keratinized mucosa is also crucial to maintain healthy periodontal or peri-implant tissues. In this study, we investigated the roles of type XVIII collagen, a collagen-glycosaminoglycan featuring an extracellular matrix component present in the basement membrane, in oral mucosal keratinization. Histological analysis of keratinized and non-keratinized oral mucosa showed that type XVIII collagen was highly expressed in keratinized mucosa. Additionally, a 3D culture system using human squamous carcinoma cells (TR146) was used to evaluate and correlate the changes in the expression of type XVIII collagen gene, COL18A1, and epithelial keratinization-related markers, e.g., keratin 1 (KRT1) and 10 (KRT10). The results showed that the increase in COL18A1 expression followed the increase in KRT1 and KRT10 mRNA levels. Additionally, loss-of-function analyses using silencing RNA targeting COL18A1 mRNA and a Col18-knockout (KO) mouse revealed that the absence of type XVIII collagen induces a dramatic decrease in KRT10 expression as well as in the number and size of keratohyalin granules. Together, the results of this study demonstrate the importance of type XVIII collagen in oral mucosal keratinization.

Exploring the Regulators of Keratinization: Role of BMP-2 in Oral Mucosa.

The oral mucosa functions as a physico-chemical and immune barrier to external stimuli, and an adequate width of the keratinized mucosa around the teeth or implants is crucial to maintaining them in a healthy and stable condition. In this study, for the first time, bulk RNA-seq analysis was performed to explore the gene expression of laser microdissected epithelium and lamina propria from mice, aiming to investigate the differences between keratinized and non-keratinized oral mucosa. Based on the differentially expressed genes (DEGs) and Gene Ontology (GO) Enrichment Analysis, bone morphogenetic protein 2 (BMP-2) was identified to be a potential regulator of oral mucosal keratinization. Monoculture and epithelial-mesenchymal cell co-culture models in the air-liquid interface (ALI) indicated that BMP-2 has direct and positive effects on epithelial keratinization and proliferation. We further performed bulk RNA-seq of the ALI monoculture stimulated with BMP-2 in an attempt to identify the downstream factors promoting epithelial keratinization and proliferation. Analysis of the DEGs identified, among others, IGF2, ID1, LTBP1, LOX, SERPINE1, IL24, and MMP1 as key factors. In summary, these results revealed the involvement of a well-known growth factor responsible for bone development, BMP-2, in the mechanism of oral mucosal keratinization and proliferation, and pointed out the possible downstream genes involved in this mechanism.

24-Nor-allobetulins possess strong α-glucosidase inhibitory activity.

A series of 24-nor-allobetulin derivatives holding 3ß-hydroxy-, oxime, methoxyoxime, lactame and 4-bromobenzylidene substituents have been synthesized and their differences in the NMR spectra were studied in detail. It was revealed that 3-oxo-24-nor-allobetulin loses selectivity in the reaction of oximation and forms a mixture of Z/E oximes (and methoxyoximes) in contract to the related derivatives of native scaffold (that forms only E-isomers). The screening of α-glucosidase inhibitory activity revealed that 24-nor-allobetulins are more active than allobetulins. The lead 3-oxo-24-nor-allobetulin with IC50 0.49 µM was more than 60-fold and 500-fold active than acarbose and 3-oxo-allobetulin, respectively. We can conclude that the removal of the C-24 methyl group significantly increased the antidiabetic effect and 24-nor-allobetulins should be identified as the new and promising scaffolds as α-glucosidase inhibitors on the basis of triterpenoids.

Short communication: Antibacterial effects of essential oils from Cinnamomum cassia bark and Eucalyptus globulus leaves-The involvements of major constituents.

Essential oils from Cinnamomum cassia bark and Eucalyptus globulus leaves have been traditionally applied for bacterial infections, through both of aromatherapy and oral application. (E)-cinnamaldehyde and 1,8 cineole have been identified as their major secondary metabolites, and are also generally considered as the main active ingredients responsible for their medicinal applications. However, ethnobotanical doctors still prefer to use whole essentials oils over purified compounds in bacterial infections. We therefore hypothesized that multi-compound extracts might exert better effects than isolated ingredients. In order to verify the hypothesis about advantages of whole materials, we examined antibacterial properties of the 2 plant essential oils in the comparison with their isolated major compounds, such as (E)-cinnamaldehyde and 1,8 cineole. Effects of liquid- and vapor-phase were examined on a set of 6 gram-positive and -negative bacteria, applying broth dilution, agar well diffusion and disc volatilization methods. In all 3 investigations, we observed that whole cinnamon and eucalyptus oils, with the lower concentrations of (E)-cinnamaldehyde (89.1%) and 1,8 cineole (61.2%), were able to induce better effects than the purified active compounds (≥ 99%). These results partly explain the advantages of using whole essential oils over isolated ingredients, and therefore support the application of traditional dosage forms for bacterial infections in ethnomedicine.

Allobetulone rearrangement to l8αH,19ßH-ursane triterpenoids with antiviral activity.

Allobetulone E-ring rearrangement under treating with HClO4 in Ac2O under reflux afforded new triterpenoids: 3,28-diacetoxy-21-acetyl-2(3),20(21)-18α,19ßH-ursandiene 3 and 3,28-diacetoxy-2(3),18(19)-oleandiene 4. 18α,19ßH-Ursanes were transformed at A- and E-rings into indolo- and bis-furfurylidene 7 derivatives. Structure elucidation was performed using COSY, NOESY, HSQC and HMBC experiments, and X-Ray analysis for 3. The potential of newly obtained 18α,19ßH-ursanes was evaluated against HCMV and HPV-11, the NCI-60 cancer cell panel and inhibition of α-glucosidase. All of the compounds have shown viral inhibition towards HCMV compared to standard drug Acyclovir. 3ß-Acetoxy-21ß-acetyl-20ß,28-epoxy-18α,19ßН-ursane 1 showed moderate activity (EC50 4.87 µM) towards the HCMV-resistant isolate (GDGr K17) compared to standard drug Cidofovir and was four times more potent than Ganciclovir. Compound 7 inhibited the cell growth of the three melanoma and one colon cancer cell. 3-Oxo-21ß-acetyl-20ß,28-epoxy-18α,19ßН-ursane 5 and compound 7 inhibited α-glucosidase with IC50 28.0 µM and 4.0 µM being from 6 to 44 times more active than acarbose.

Primary cesarean section rate among full-term pregnant women with non-previous uterine scar in a hospital of Vietnam.

Aim: This article aims to determine the contributing indications for primary cesarean sections among full-term pregnant women with non-previous uterine scars and suggests several potential solutions to reduce the cesarean section rate. Methods: This is a descriptive study with data being retrospectively collected from electronic medical records (EMRs) at Hanoi Obstetrics & Gynecology Hospital, Vietnam, in 2020. We studied 23,631 women at ≥37 weeks of gestation with non-previous uterine scars. Main ICD-10 categories of diagnosis on the EMRs were used to classify the indications. The proportions of indications for primary cesarean sections were calculated, thereby offering potential solutions to reduce the cesarean section rate. Results: The proportion of cesarean sections among full-term pregnancies with non-previous uterine scars was 40.7%. The most common indications for primary cesarean sections were non-reassuring fetal heart rate tracing (40%), labor arrest (31%), and maternal request (11%). Among the low-risk pregnant women, the cesarean section rate was 35.9%, of which the percentages of labor arrest and non-reassuring fetal heart rate tracings and maternal request were 13.6%, 17.7%, and 4.6%, respectively. Conclusions: The proportion of primary cesarean sections among full-term pregnancies with non-previous uterine scars is high; non-reassuring fetal heart rate tracings, labor arrest, and maternal request were three main indications. It is necessary to build the strategies of health organizations regarding the management of clinical practices and the programs improving the knowledge, attitudes, practices of pregnant women and obstetricians regarding cesarean sections.

Improvement of symptoms after hysteroscopic isthmoplasty in women with abnormal uterine bleeding and expected pregnancy: A prospective study.

BACKGROUND: Cesarean scar myometrial defect as known as niche is associated with postmenstrual spotting, suprapubic pain and secondary infertility. Hysteroscopic isthmoplasty has been proposed in the treatment of niche. This study aims to determine the safety and effectiveness of hysteroscopic isthmoplasty in postmenstrual spotting treatment and improvement of spontaneous conceiving. MATERIALS AND METHOD: A prospective study was performed at Hanoi Obstetrics and Gynecology Hospital, Vietnam. We studied women who developed postmenstrual spotting related to niches and had desired to conceive for more than six months. Women with residual myometrium less than 2.5 mm were excluded. Twenty-three eligible women underwent hysteroscopic isthmoplasty with four main steps, including identification of relevant anatomy, resection of the cephalad edge of fibrosis, resection of the caudal edge of fibrosis, and ablation of the niche base. Participants were followed up at 1, 3, and 6 months postoperatively. RESULTS: The mean surgical duration was 17 min, and no complications took place. The number of women with improved postmenstrual spotting symptoms after 1, 3, and 6 months were 39.1% (9/23), 61.9% (13/21) and 68.8% (11/16), respectively. Suprapubic pain resolved in 94% (15/16) of the women in the first month. The rate of spontaneous pregnancies within 6 months of isthmoplasty was 30.4% (7/23). There were no differences in depth niche and residual myometrium thickness on ultrasound in the period before and after hysteroscopy. CONCLUSION: Our study supports that hysteroscopic isthmoplasty is a safe and effective procedure for women with a niche and postmenstrual spotting and wish to conceive.

Risk factors for root caries annual incidence and progression among older people requiring nursing care: A one-year prospective cohort study.

PURPOSE: We aimed to determine root caries annual incidence (RCAI) and root caries annual progression (RCAP) and risk factors for them among older people requiring nursing care. METHODS: The target population comprised 186 dentate individuals aged ≥ 65 years who required nursing care while living in nursing homes (NHs) or their own homes (OHs) in Okayama, Japan. Survey items included presence/absence and severity of root caries, age, sex, living environment (NH or OH), the Clinical Dementia Rating, and the Barthel Index (BI). Baseline surveys were conducted from 2015 to 2017; subjects were followed up for one year. RCAI and RCAP per tooth and per person were calculated, and risk factors for them were identified using generalized estimating equations. RESULTS: In total, 104 individuals (mean age: 82.0 ± 12.4 years) completed the follow-up survey. RCAIs per tooth and per person were 14.6% (173/1188) and 59.6% (62/104), respectively. RCAP per tooth was 22.5% (51/227 teeth with root caries at baseline). Significant risk factors for RCAI were living environment (OH, odds ratio [OR]: 2.14), sex (male, OR: 1.84), clasped tooth (OR: 1.82), and older age (OR: 1.05) at baseline. Significant risk factors for RCAP were sex (male, OR: 5.20), regular dental checkup (OR: 2.74), and high BI score (OR: 1.02) at baseline. CONCLUSION: At one-year follow-up, 59.6% of the subjects developed at least one root caries. Risk factors for RCAI were living environment (OH), male, clasped tooth, and older age, whereas those for RCAP were male, regular dental checkup, and high BI score.

Dangerous subtlety: relationship-related determinants of consistency of condom use among female sex workers and their regular, non-commercial partners in Hai Phong, Viet Nam.

Research indicates female sex workers use condoms more consistently with their clients than with regular, non-commercial partners (partners). The purpose of this study was to better understand the relationship between couple communication and HIV risk behavior by examining (1) sex worker-partner divergence on communication measures and (2) the association between intra-couple communication divergence and consistent condom use. In this cross-sectional study, 50 sex workers and their partners in Hai Phong, Viet Nam were separately asked about their relationships and condom use. When asked about HIV risk communication in their relationship, sex workers reported significantly higher HIV communication content than their partners (p < 0.001). Higher communication divergence between partners was associated with a decreased likelihood of consistent condom use (OR 0.54 95% CI 0.30, 0.97). Sex workers urgently need interventions that build their communication skills and address their risk behavior in non-commercial relationships.

Tryptophan and Kynurenine Enhances the Stemness and Osteogenic Differentiation of Bone Marrow-Derived Mesenchymal Stromal Cells In Vitro and In Vivo.

Aging tissues present a progressive decline in homeostasis and regenerative capacities, which has been associated with degenerative changes in tissue-specific stem cells and stem cell niches. We hypothesized that amino acids could regulate the stem cell phenotype and differentiation ability of human bone marrow-derived mesenchymal stromal cells (hBMSCs). Thus, we performed a screening of 22 standard amino acids and found that D-tryptophan (10 µM) increased the number of cells positive for the early stem cell marker SSEA-4, and the gene expression levels of OCT-4, NANOG, and SOX-2 in hBMSCs. Comparison between D- and L-tryptophan isomers showed that the latter presents a stronger effect in inducing the mRNA levels of Oct-4 and Nanog, and in increasing the osteogenic differentiation of hBMSCs. On the other hand, L-tryptophan suppressed adipogenesis. The migration and colony-forming ability of hBMSCs were also enhanced by L-tryptophan treatment. In vivo experiments delivering L-tryptophan (50 mg/kg/day) by intraperitoneal injections for three weeks confirmed that L-tryptophan significantly increased the percentage of cells positive for SSEA-4, mRNA levels of Nanog and Oct-4, and the migration and colony-forming ability of mouse BMSCs. L-kynurenine, a major metabolite of L-tryptophan, also induced similar effects of L-tryptophan in enhancing stemness and osteogenic differentiation of BMSCs in vitro and in vivo, possibly indicating the involvement of the kynurenine pathway as the downstream signaling of L-tryptophan. Finally, since BMSCs migrate to the wound healing site to promote bone healing, surgical defects of 1 mm in diameter were created in mouse femur to evaluate bone formation after two weeks of L-tryptophan or L-kynurenine injection. Both L-tryptophan and L-kynurenine accelerated bone healing compared to the PBS-injected control group. In summary, L-tryptophan enhanced the stemness and osteoblastic differentiation of BMSCs and may be used as an essential factor to maintain the stem cell properties and accelerate bone healing and/or prevent bone loss.

Changes in, and predictors of, quality of life among patients with unstable angina after percutaneous coronary intervention.

RATIONALE, AIMS AND OBJECTIVES: Changes in, and predictors of, quality of life (QoL) among unstable angina patients are informative for both clinical and public health practice. However, there is little research on this topic, especially in health care settings with limited resources. This study aims to detect changes in QoL and its associated factors among patients with unstable angina after percutaneous coronary intervention. METHODS: A longitudinal design was conducted with two repeated rounds of measurements, 1 and 3 months after intervention, using the generic SF-36 questionnaire, in 120 patients from Vietnam National Heart Institute. A linear mixed-effects model was used to assess changes in patient QoL over time while adjusting for other covariates. RESULTS: Only two out of eight QoL subscales (social functioning and emotional well-being) declined after 1 month, but these tended to rise again after 3 months, while scores of all other QoL subscales increased. Adjusting for covariates, QoL increased slightly after 1 month of intervention (ß = 0.65, 95%CI = -0.86 to 2.16) but improved by almost six QoL points after 3 months (ß = 5.99, 95%CI = 4.48 to 7.50). Four confounders significantly associated with a decline in QoL were older age, being retired, living in rural areas, and having abnormal troponin level. CONCLUSION: QoL of the patients with unstable angina improves significantly 3 months after intervention, rather than after 1 month. More attention should be given to patients, who are old, retired, live in rural areas and have abnormal troponin level.

Six-year follow-up assessment of prosthesis survival and oral health-related quality of life in individuals with partial edentulism treated with three types of prosthodontic rehabilitation.

Purpose The purpose of the study was to compare the long-term performance of three prostheses for partial edentulism: implant-supported, fixed denture (IFD), fixed partial denture (FPD), and removable partial denture (RPD), in terms of prosthesis survival and oral health-related quality of life (OHRQoL).Methods The 138 patients in our previous study (Kimura et al., 2012) received one of the three prosthetic treatments and answered a validated OHRQoL questionnaire before and immediately after treatment. In the present study, the patients were followed up six years after treatment using medical records and OHRQoL examinations to evaluate prosthesis survival and change in OHRQoL. The cumulative survival rates were calculated using the Kaplan-Meier analysis. The Steel-Dwass test was used to compare the median OHRQoL scores at the three time points.Results For the 105 patients (66.8 ± 10.8 years, IFD/FPD/RPD: 58/27/20 patients) who successfully completed the follow-up assessments, the six-year estimated cumulative survival rates of the IFDs, FPDs, and RPDs were 94.7%, 77.4%, and 33.3%, respectively. The log-rank tests indicated that the survival curves were significantly different (IFDs vs. FPDs: p = 0.01; RPDs vs. IFDs, FPDs: p < 0.01). The median OHRQoL scores of the IFD group immediately after treatment and six years after treatment were significantly higher than those observed before treatment (p < 0.01). There was no significant difference in the median OHRQoL scores among the three time points in the RPD or FPD groups.Conclusions IFDs showed significantly longer survival rates than FPDs and RPDs in partially edentulous patients. Only in the IFD patients was the OHRQoL level six years after treatment significantly higher than that before treatment.

Bone Marrow Cells Inhibit BMP-2-Induced Osteoblast Activity in the Marrow Environment.

Bone morphogenetic protein 2 (BMP-2) is widely known as a potent growth factor that promotes bone formation. However, an increasing number of studies have demonstrated side effects of BMP-2 therapy. A deeper understanding of the effect of BMP-2 on cells other than those involved directly in bone remodeling is of fundamental importance to promote a more effective delivery of BMP-2 to patients. In this study, we aimed to investigate the effect of BMP-2 in the marrow environment. First, BMP-2 adsorbed onto titanium implants was delivered at the tooth extraction socket (marrow-absent site) or in the mandible marrow of beagle dogs. BMP-2 could induce marked bone formation around the implant at the tooth extraction socket. Surprisingly, however, no bone formation was observed in the BMP-2-coated titanium implants inserted in the mandible marrow. In C57BL/6 mice, BMP-2 adsorbed in freeze-dried collagen pellets could induce bone formation in marrow-absent calvarial bone. However, similar to the canine model, BMP-2 could not induce bone formation in the femur marrow. Analysis of osteoblast differentiation using Col1a1(2.3)-GFP transgenic mice revealed a scarce number of osteoblasts in BMP-2-treated femurs, whereas in the control group, osteoblasts were abundant. Ablation of femur marrow recovered the BMP-2 ability to induce bone formation. In vitro experiments analyzing luciferase activity of C2C12 cells with the BMP-responsive element and alkaline phosphatase activity of MC3T3-E1 osteoblasts further revealed that bone marrow cells inhibit the BMP-2 effect on osteoblasts by direct cell-cell contact. Collectively, these results showed that the effect of BMP-2 in inducing bone formation is remarkably repressed by marrow cells via direct cell-cell contact with osteoblasts; this opens new perspectives on the clarification of the side-effects associated with BMP-2 application. © 2018 American Society for Bone and Mineral Research.

Contribution to the genus Okinawepipona Yamane (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with description of a new species.

A new species of the genus Okinawepipona Yamane from Vietnam is described and figured: Okinawepipona yty Nguyen, sp. nov. (northern Vietnam). Biology of O. yty Nguyen, sp. nov. and O. nigra Nguyen Xu, 2014 is recorded. A key to the four species known in the genus is provided.

Type IV collagen α6 chain is a regulator of keratin 10 in keratinization of oral mucosal epithelium.

Keratinized mucosa is of fundamental importance to maintain healthy gingival tissue, and understanding the mechanisms of oral mucosa keratinization is crucial to successfully manage healthy gingiva. Previous studies have shown a strong involvement of the basement membrane in the proliferation and differentiation of epithelial cells. Therefore, first, to identify the keratinized mucosa-specific basement membrane components, immunohistochemical analysis for the six alpha chains of type IV collagen was performed in 8-week-old mice. No difference in the expression pattern of type IV collagen α1(IV) and α2(IV) chains was observed in the keratinized and non-keratinized mucosa. Interestingly, however, type IV collagen α5(IV) and α6(IV) chains specifically were strongly detected in the keratinized mucosa. To analyze the functional roles of the type IV collagen isoform α6(IV) in oral mucosa keratinization, we analyzed Col4a6-knockout mice. Epithelial developmental delay and low levels of KRT10 were observed in new-born Col4a6-knockout mice. Additionally, in vitro experiments with loss-of function analysis using human gingival epithelial cells confirmed the important role of α6(IV) chain in epithelial keratinization. These findings indicate that α112:α556 (IV) network, which is the only network that includes the α6(IV) chain, is one regulator of KRT10 expression in keratinization of oral mucosal epithelium.