Search

Aims/Introduction: Periodontal disease, a chronic inflammation induced by bacteria, is closely linked with diabetes mellitus. Many complications associated with diabetes are related to epigenetic changes. However, the exact epigenetic changes whereby diabetes affects periodontal disease remain largely unknown. Thus, we sought to investigate the role of diabetes‐dependent epigenetic changes of gingival tissue in the susceptibility to periodontal disease. Materials and Methods: We studied the effect of streptozotocin‐induced diabetes in minipigs on gingival morphological and epigenetic tissue changes. Accordingly, we randomly divided six minipigs into two groups: streptozotocin‐induced diabetes group, n = 3; and non‐diabetes healthy control group, n = 3. After 85 days, all animals were killed, and gingival tissue was collected for histology, deoxyribonucleic acid methylation analysis and immunohistochemistry. Results: A diabetes mellitus model was successfully created, as evidenced by significantly increased blood glucose levels, reduction of pancreatic insulin‐producing β‐cells and histopathological changes in the kidneys. The gingival tissues in the diabetes group presented acanthosis of both gingival squamous epithelium and sulcular/junctional epithelium, and a significant reduction in the number and length of rete pegs. Deoxyribonucleic acid methylation analysis showed a total of 1,163 affected genes, of which 599 and 564 were significantly hypermethylated and hypomethylated, respectively. Immunohistochemistry staining showed that the hypomethylated genes – tumor necrosis factor‐α and interleukin‐6 – were positively expressed under the junctional epithelium area in the diabetes group. Conclusions: Diabetes mellitus induces morphological and epigenetic changes in periodontal tissue, which might contribute to the increased susceptibility of periodontal diseases in patients with diabetes. [ABSTRACT FROM AUTHOR]

The Wiener polarity index Wp of a graph is defined as the number of unordered pairs of its vertices at distance 3. The problem of finding trees attaining the maximum Wp value, among all chemical trees of a fixed order n, was solved in the paper (Mol. Inf. 2019, 38, 1800076) for n ≥ 8. Motivated by the usage of Wp in a recent publication (J. Chem. Inf. Model. 2020, 60, 1224–1234), in this article we extend the work done in the aforementioned paper by giving a further ordering of chemical trees with respect to the maximum value of Wp. More precisely, we characterize the trees having the second maximum Wp value (which is 3n − 16) from the class of all chemical trees of a fixed order n, for n ≥ 9. [ABSTRACT FROM AUTHOR]

The first and second Zagreb indices are the molecular descriptors that were appeared within a study of molecular modeling more than four decades ago. The coindex versions of these Zagreb indices were introduced around one decade before. Finding trees with the first two extremum Zagreb indices/coindices from the class of all chemical trees of a fixed order is a chemical‐graph‐theoretic problem whose partial solution is known. This paper is devoted to reporting the complete solution of the aforementioned problem. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the influence of systemic zoledronate administration on the osseointegration of titanium implants with different surface topography in rat maxillae. Methods: Twenty Sprague‐Dawley rats were divided into two groups—test (bisphosphonate) and control (healthy). Bisphosphonate administration began three weeks prior to implant placement, and the animals received zoledronate (66 μg/kg) three times per week. Forty endosseous implants with a moderately rough (20 implants) or a turned surface (20 implants) were immediately placed bilaterally into extraction sockets of maxillary first molars. Animals were sacrificed after 14 and 28 days of healing, and en bloc specimens were harvested for histological and histomorphometric analysis. Osseointegration was quantified by measuring the percentage of bone‐to‐implant contact. Results: Bone‐to‐implant contact (BIC) (mean ± SD) values of moderately rough and turned implants at day 14 in test group were 17.62 ± 6.68 and 10.69 ± 1.48, respectively, while in the control group, they were 46.36 ± 5.08 and 33.29 ± 8.89, respectively. At day 28, BIC values of moderately rough and turned implants in the test group were 25.94 ± 7.87 and 7.83 ± 4.30, respectively, while in the control group, they were 72.99 ± 6.60 and 47.62 ± 18.19, respectively. Statistically significant higher BIC values were measured on moderately rough implants compared to turned implants at 28 days, and the control group compared to the test group for both implant surfaces. Histological observations for the control and the test groups demonstrated initial bone formation around moderately rough implants not only on the surface of the parent bone, as was the case with the turned surfaced implants, but also along the implant surface itself. Conclusions: Systemic zoledronate administration negatively influences osseointegration. Osseointegration was enhanced adjacent to moderately rough compared to turned implants in both the presence and absence of systemic zoledronate administration. Therefore, topographical surface modification may partially offset the negative impact of zoledronate administration. [ABSTRACT FROM AUTHOR]

This article is devoted to establishing some extremal results with respect to the difference of two well-known bond incident degree indices [atom-bond connectivity ( ABC) index and Randić ( R) index] for the chemical graphs representing alkanes. More precisely, the first three extremal trees with respect to ABC - R are characterized among all n-vertex binary trees (the trees with maximum degree at most 3). The n-vertex chemical trees (the trees with maximum degree at most 4) having the first three maximum ABC - R values are also determined. [ABSTRACT FROM AUTHOR]

Background: Osteoporosis is associated with widespread periodontitis and impaired periodontal healing. However, there is a lack of information about the outcomes of regenerative approaches under the influence of osteoporosis. This study investigates the effect of leptin (LEP) overexpression on the regenerative potential of bone marrow stromal cells (BMSCs) in an osteoporotic rat periodontal fenestration defect model.Methods: Rat BMSCs were transfected with adenoviruses harboring the human (h)LEP gene. Cell proliferation and osteogenic differentiation were evaluated. A β-tricalcium phosphate scaffold seeded with transfected cells was implanted into nude mice to investigate ectopic osteogenesis and into an osteoporotic rat defect to study periodontal regeneration. Regenerated periodontal and bone-like tissues were analyzed by histologic methods.Results: hLEP overexpression induced osteogenic differentiation of BMSCs as evidenced by the upregulation of osteogenesis-related genes such as Runt-related transcription factor 2, alkaline phosphatase (ALP), and collagen Type I, as well as increased ALP activity and enhanced mineralization. Mice implanted with hLEP-BMSC-containing scaffolds showed more extensive formation of bone-like tissue than those in other groups. Periodontal defects were also filled to a greater degree when treated with hLEP-BMSCs and contained cementum and a well-organized periodontal ligament after 10 and 28 days.Conclusion: hLEP overexpression in BMSCs can stimulate periodontal regeneration in osteoporotic conditions and might be a promising strategy for periodontal regeneration in patients with osteoporosis. [ABSTRACT FROM AUTHOR]

Objectives Published information regarding the use of rat jawbones for dental implant osseointegration research is limited and often inconsistent. This study assessed the suitability and feasibility of placing dental implants into the rat maxilla and to establish parameters to be used for dental implant research using this model. Materials and methods Forty-two customized titanium implants (2 × 3 mm) were placed bilaterally in the maxillary first molar area of 21 Sprague-Dawley rats. Every animal received two implants. The animals were subsequently sacrificed at days 3, 7, 14, 28 and 56 post-surgery. Resin-embedded sections of the implant and surrounding maxilla were prepared for histological and histomorphometric analyses. Results The mesial root of the first molar in the rat maxilla was the optimal site to place the implant. Although the most apical 2-3 threads of the implant penetrated into the sinus cavity, 2 mm of the remaining implant was embedded in the bone. New bone formation at day 7 around the implant increased further at day 14, as measured by the percentage of bone-to-implant contact (% BIC) and new bone area (% BA) in the implant thread chambers (55.1 ± 8.9% and 63.7 ± 7.7%, respectively). There was a further significant increase between day 14 and 28 ( P < 0.05), however, no significant differences were found between day 28 and 56 in either % BIC or % BA. Conclusions The mesial root socket of the first molar in the rat maxilla is a useful model for dental implant research. Osseointegration following implant placement as measured by BIC plateaued after 28 days. The recommended implant dimensions are 1.5 mm in diameter and 2 mm in length. [ABSTRACT FROM AUTHOR]

Objective Simvastatin has been shown to enhance osseointegration of pure titanium implants in osteoporotic rats. This study aimed to evaluate the relationship between the serum level of bone formation markers and the osseointegration of pure titanium implants in osteoporotic rats treated with simvastatin. Materials and methods Fifty-four female Sprague-Dawley rats, aged 3 months, were randomly divided into three groups: Sham-operated group ( SHAM; n = 18), ovariectomized group ( OVX; n = 18), and ovariectomized with simvastatin treatment group ( OVX + SIM; n = 18). Fifty-six days after ovariectomy, screw-shaped titanium implants were inserted into the tibiae. Simvastatin was administered orally at 5 mg/kg each day after the placement of the implant in the OVX + SIM group. The animals were killed at either 28 or 84 days after implantation and the undecalcified tissue sections were processed for histological analysis. Total alkaline phosphatase ( ALP), bone-specific alkaline phosphatase ( BALP) and bone Gla protein ( BGP) were measured in all animal sera collected at the time of euthanasia and correlated with the histological assessment of osseointegration. Results The level of ALP in the OVX group was higher than the SHAM group at day 28, with no differences between the three groups at day 84. The level of BALP in the OVX + SIM group was significantly higher than both OVX and SHAM groups at days 28. Compared with day 28, the BALP level of all three groups showed a significant decrease at day 84. There were no significant differences in BGP levels between the three groups at day 28, but at day 84, the OVX + SIM group showed significantly higher levels than both the OVX and SHAM groups. There was a significant increase in BGP levels between days 28 and 84 in the OVX + SIM group. The serum bone marker levels correlated with the histological assessment showing reduced osseointegration in the OVX compared to the SHAM group which is subsequently reversed in the OVX + SIM group. Conclusion The results from this study indicate that the serum level of bone formation markers, especially BALP and BGP, could be correlated with the degree of osseointegration around titanium implants in osteoporotic rats treated with simvastatin. [ABSTRACT FROM AUTHOR]

The Wiener index of a connected graph is defined as the sum of distances between all unordered pairs of its vertices. It has found various applications in chemical research. We determine the minimum and the maximum Wiener indices of trees with given bipartition and the minimum Wiener index of monocyclic graphs with given bipartition, respectively. We also characterize the graphs whose Wiener indices attain these values. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 [ABSTRACT FROM AUTHOR]

The Randić (connectivity) index is one of the most successful molecular descriptors in structure‐property and structure‐activity relationships studies. We determine the n‐vertex trees with the third for n ≥ 7, the fourth for n ≥ 10, the fifth and the sixth for n ≥ 11 maximum Randić indices, unicyclic graphs with the third for n ≥ 5, the fourth for n ≥ 7, and the fifth for n ≥ 8 maximum Randić indices, and bicyclic graphs with the second and the third for n ≥ 7, the fourth and the fifth for n ≥ 9 maximum Randić indices. We also determine the n‐vertex tree(s) for n ≥ 6 with the fifth minimum Randić index, unicyclic graphs for n ≥ 5 with the second, the third and the fourth minimum Randić indices, and bicyclic graph(s) for n ≥ 5 with the second minimum Randić index. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 [ABSTRACT FROM AUTHOR]

Objectives: Osteoporosis is known to impair the process of implant osseointegration. The recent discovery that statins (HMG-CoA reductase inhibitors) act as bone anabolic agents suggests that statins can be used as potential agents in the treatment of osteoporosis. Therefore, we hypothesized that statins will promote osteogenesis around titanium implants in subjects with osteoporosis. Material and methods: Fifty-four female Sprague Dawley rats, aged 3 months old, were randomly divided into three groups: Sham-operated group (SHAM; n=18), ovariectomized group (OVX; n=18), and ovariectomized with Simvastatin treatment group (OVX+SIM; n=18). Fifty-six days after being ovariectomized (OVX), screw-shaped titanium implants were inserted into the tibiae. Simvastatin was administered orally at 5 mg/kg each day after the placement of the implant in the OVX+SIM group. The animals were sacrificed at either 28 or 84 days after implantation and the undecalcified tissue sections were obtained. Bone-to-implant contact (BIC) and bone area (BA) within the limits of implant threads were measured around the cortical (zone A) and cancellous (zone B) bone regions. Furthermore, bone density (BD) of zone B in a 500 μm wide zone lateral to the implants was also measured. Results: There were no significant differences in BIC and BA measurements in zone A in any of the three groups at either 28 or 84 days after implantation ( P>0.05). By contrast, in zone B, significant differences in the measurement of BIC, BA, and BD were observed at 28 and 84 days between all three groups. Bone healing decreased with lower BIC, BA, and BD around implant in OVX group compared with other two groups, and Simvastatin reversed the negative effect of OVX on bone healing around implants with the improvement of BIC, BA, and BD in zone B. Conclusion: Osteoporosis can significantly influence bone healing in the cancellous bone around titanium implants and Simvastatin was shown to significantly improve the osseointegration of pure titanium implants in osteoporotic rats. [ABSTRACT FROM AUTHOR]

Three general molecular descriptors, namely the general sum‐connectivity index, general Platt index and ordinary generalized geometric‐arithmetic index, are studied here. Best possible bounds for the aforementioned descriptors of arbitrary saturated hydrocarbons are derived under certain constraints. These bounds are expressed in terms of number of carbon atoms and number of carbon‐carbon bonds of the considered hydrocarbons. [ABSTRACT FROM AUTHOR]

The modified first Zagreb connection index (ZC1*) is a molecular descriptor, which was initially appeared within a formula of the total electron energy of alternant hydrocarbons in 1972. In a recent paper [A. Ali, N. Trinajstić, A novel/old modification of the first Zagreb index, Mol. Inform. 37 (2018) 1800008], it was observed that the molecular descriptor ZC1* correlates well with the entropy and acentric factor of octane isomers. In this article, the molecules with the first three maximal ZC1* values as well as the first three minimal ZC1* values are determined from the family of all alkanes with n carbon atoms, for n≥6. This extends the main results of the aforementioned paper. [ABSTRACT FROM AUTHOR]

The Wiener polarity index (usually denoted by Wp) of an alkane is the number of unordered pairs of carbon atoms which are separated by three carbon–carbon bonds. This topological index Wp is useful for predicting the boiling points of alkanes. Deng [MATCH Commun. Math. Comput. Chem. 66 (2011) 305] proved that the maximum Wp value among all alkanes, with n carbon atoms, is 3n-15. The main purpose of present paper is to find all those alkanes with n carbon atoms, which attain the maximum value of Wp. [ABSTRACT FROM AUTHOR]