Effects of Calcium Supplementation on Glucose and Insulin Levels of Athletes at Rest and After Exercise

This study was performed to determine how the calcium supplementation for a 4-week period affects the glucose and insulin levels at rest and at exhaustion in athletes. This is a 4-week study performed on 30 healthy subjects varying between 18 and 22 ages. Subjects were separated into three groups: first group (group supplemented with calcium, sedentary group), second group (calcium supplementations + exercise group), and third group (training group). Glucose and insulin parameters of the groups were measured four times, at rest and exhaustion in the beginning of the research and at rest and exhaustion after the end of 4 weeks application period. Exhaustion measurements both before and after the supplementations significantly decreased in compared to rest measurements in terms of insulin (p < 0.05). Significant difference was not determined in the glucose values of groups. In terms of glucose, values increased in all of the three groups occurred with exercise both before and after the supplementation by exercise and exhaustion (p < 0.05). The results of our study indicate that calcium gluconate supplementations for 4 weeks in sedentary subjects and athletes did not significantly affect plasma insulin levels at rest and exhaustion. However, glucose levels were affected by calcium supplementation and exhausting exercise in athletes.     

Pressure Cycling Technology Assisted Mass Spectrometric Quantification of Gingival Tissue Reveals Proteome Dynamics during the Initiation and Progression of Inflammatory Periodontal Disease

Understanding the progression of periodontal tissue destruction is at the forefront of periodontal research. The authors aimed to capture the dynamics of gingival tissue proteome during the initiation and progression of experimental (ligature‐induced) periodontitis in mice. Pressure cycling technology (PCT), a recently developed platform that uses ultra‐high pressure to disrupt tissues, is utilized to achieve efficient and reproducible protein extraction from ultra‐small amounts of gingival tissues in combination with liquid chromatography‐tandem mass spectrometry (MS). The MS data are processed using Progenesis QI and the regulated proteins are subjected to METACORE, STRING, and WebGestalt for functional enrichment analysis. A total of 1614 proteins with ≥2 peptides are quantified with an estimated protein false discovery rate of 0.06%. Unsupervised clustering analysis shows that the gingival tissue protein abundance is mainly dependent on the periodontitis progression stage. Gene ontology enrichment analysis reveals an overrepresentation in innate immune regulation (e.g., neutrophil‐mediated immunity and antimicrobial peptides), signal transduction (e.g., integrin signaling), and homeostasis processes (e.g., platelet activation and aggregation). In conclusion, a PCT‐assisted label‐free quantitative proteomics workflow that allowed cataloging the deepest gingival tissue proteome on a rapid timescale and provided novel mechanistic insights into host perturbation during periodontitis progression is applied.     

Adaptation of rat gastric tissue against indomethacin toxicity

Indomethacin is used in the treatment of inflammatory diseases. But the drug toxicity limits its usage. This study investigated whether adaptation occurred after various dosages of repeated (chronic) indomethacin in rats to the gastro-toxic effects of indomethacin. It also examined whether the adaptation was related to oxidant–antioxidant mechanisms and oxidative DNA damage in gastric tissue. To illuminate the adaptation mechanism in the gastric tissue of rats given various dosages of chronic indomethacin, the levels of oxidants and antioxidants (GSH, MDA, NO, SOD and MPO), activities of COX-1 and COX-2 enzymes and oxidative DNA damage (8-OHd Gua/10⁵ Gua) were measured. Results were compared to 25-mg/kg single-dose indomethacin group, and the role of oxidant and antioxidant parameters and oxidative DNA damage in the adaptation mechanism was evaluated. The average ulcer areas of gastric tissue of the 0.5-, 1-, 2-, 3-, 4-, and 5-mg/kg dosages of chronic indomethacin given to rats were 19.5 ± 3.7, 12.5 ± 3.3, 10 ± 5.2, 4.5 ± 3.6, 8.6 ± 2.4, and 9.5 ± 2.1 mm², respectively. This rate was measured as 21.3 ± 2.6 mm² in the single-dose indomethacin group. Consequently, after various dosages of repeated (chronic) indomethacin administration in rats, it was observed that a clear adaptation developed against gastric damage and that gastric damage was reduced. The best adaptation was observed in the gastric tissue of the 3-mg/kg chronic indomethacin group. In parallel with the damage reduction, the oxidant parameters (MDA and MPO) and oxidative DNA damage (8-OHd Gua/10⁵ Gua) were reduced, and the antioxidant parameters (GSH, NO and SOD) were increased. There is no relation between COX enzymes and adaptation mechanism. This circumstance shows that not COX-1 and COX-2 enzymes, oxidant and antioxidant parameters may play a role in the adaptation mechanism.     

Influence of the Mechanical Environment on the Engineering of Mineralised Tissues Using Human Dental Pulp Stem Cells and Silk Fibroin Scaffolds

Teeth constitute a promising source of stem cells that can be used for tissue engineering and regenerative medicine purposes. Bone loss in the craniofacial complex due to pathological conditions and severe injuries could be treated with new materials combined with human dental pulp stem cells (hDPSCs) that have the same embryonic origin as craniofacial bones. Optimising combinations of scaffolds, cells, growth factors and culture conditions still remains a great challenge. In the present study, we evaluate the mineralisation potential of hDPSCs seeded on porous silk fibroin scaffolds in a mechanically dynamic environment provided by spinner flask bioreactors. Cell-seeded scaffolds were cultured in either standard or osteogenic media in both static and dynamic conditions for 47 days. Histological analysis and micro-computed tomography of the samples showed low levels of mineralisation when samples were cultured in static conditions (0.16±0.1 BV/TV%), while their culture in a dynamic environment with osteogenic medium and weekly µCT scans (4.9±1.6 BV/TV%) significantly increased the formation of homogeneously mineralised structures, which was also confirmed by the elevated calcium levels (4.5±1.0 vs. 8.8±1.7 mg/mL). Molecular analysis of the samples showed that the expression of tooth correlated genes such as Dentin Sialophosphoprotein and Nestin were downregulated by a factor of 6.7 and 7.4, respectively, in hDPSCs when cultured in presence of osteogenic medium. This finding indicates that hDPSCs are able to adopt a non-dental identity by changing the culture conditions only. Also an increased expression of Osteocalcin (1.4x) and Collagen type I (1.7x) was found after culture under mechanically dynamic conditions in control medium. In conclusion, the combination of hDPSCs and silk scaffolds cultured under mechanical loading in spinner flask bioreactors could offer a novel and promising approach for bone tissue engineering where appropriate and rapid bone regeneration in mechanically loaded tissues is required.     

Whole-genome patenting

Gene patenting is now a familiar commercial practice, but there is little awareness that several patents claim ownership of the complete genome sequence of a prokaryote or virus. When these patents are analysed and compared to those for other biological entities, it becomes clear that genome patents seek to exploit the genome as an information base and are part of a broader shift towards intangible intellectual property in genomics.     

Porphyromonas gingivalis regulates the RANKL-OPG system in bone marrow stromal cells

Porphyromonas gingivalis is a Gram-negative anaerobe implicated in chronic periodontitis, a bacterial-induced inflammatory condition that causes destruction of the periodontal connective tissues and underlying alveolar bone. The receptor activator of nuclear factor-kappaB ligand (RANKL) is a cytokine that directly stimulates osteoclastogenesis and bone resorption, whereas its decoy receptor osteoprotegerin (OPG) blocks this action. This study aimed to investigate the effects of P. gingivalis culture supernatants on RANKL and OPG expression in W20-17 bone marrow stromal cells, and evaluate the involvement of its virulence factors, particularly gingipains and lipopolysaccharide. P. gingivalis up-regulated RANKL and down-regulated OPG mRNA expression and protein production. These effects were blocked by indomethacin, suggesting mediation by prostaglandins. Furthermore, P gingivalis induced the production of prostaglandin E(2). Heat-inactivation, or chemical inhibition of P. gingivalis gingipains did not affect RANKL and OPG regulation. However, lipopolysaccharide depletion by polymyxin B abolished RANKL induction, and partly rescued the suppression of OPG. In conclusion, P. gingivalis regulates the RANKL-OPG system via prostaglandin E(2) in bone marrow stromal cells, in a manner that favours osteoclastogenesis. A non-proteolytic and non-proteinaceous P. gingivalis component is involved in these events, most probably its lipopolysaccharide. This activity may contribute to the bone loss characteristic of periodontitis.     

Alpha-Tocopherol Decreases Iron-Induced Hippocampal and Nigral Neuron Loss

There are many studies about iron-induced neuronal hyperactivity and oxidative stress. Some reports also showed that iron levels rise in the brain in some neurodegenerative diseases such as Parkinson’s (PD) and Alzheimer’s disease (AD). It has been suggested that excessive iron level increases oxidative stress and causes neuronal death. Tocopherols act as a free radical scavenger when phenoxylic head group encounters a free radical. We have aimed to identify the effect of α-tocopherol (Vitamin E) on iron-induced neurotoxicity. For this reason, rats were divided into three groups as control, iron, and iron + α-tocopherol groups. Iron chloride (200 mM in 2.5 μl volume) was injected into brain ventricle of iron and iron + α-tocopherol group rats. Same volume of saline (2.5 μl) was given to the rats belonging to control group. Rats of iron + α-tocopherol group received intraperitoneally (i.p.) α-tocopherol (100 mg/kg/day) for 10 days. After 10 days, rats were perfused intracardially under deep urethane anesthesia. Removed brains were processed using standard histological techniques. The numbers of neurons in hippocampus and substantia nigra of all rats were estimated by stereological techniques. Results of present study show that α-tocopherol decreased hippocampal and nigral neuron loss from 51.7 to 12.1% and 41.6 to 17.8%, respectively. Findings of the present study suggest that α-tocopherol may have neuroprotective effects against iron-induced hippocampal and nigral neurotoxicity and it may have a therapeutic significance for neurodegenerative diseases involved iron.     

The investigation of the ultrastructural neutrophil changes in alloxan-induced diabetes in rats: response to a chemotactic challenge

Experimental diabetes is one of the most popular conditions in which to study the relation between neutrophil leukocyte activity and periodontal destruction. The aetiology of neutrophil dysfunction in the gingival tissue associated with diabetes has yet to be clarified. Diabetes in rats decreases neutrophil chemotactic activity in proportion to the severity of this systemic disorder. The present study was carried out to evaluate the relationship between the severity of diabetes and the neutrophil response to two chemotactic agents, and to correlate the observed neutrophil defects with the degree of diabetes. In this study two chemotactic agents, casein (0.2 μl, 2 mg ml^?1) or N‐formylmethionylleucylphenylalanine (FMLP; 0.2 μl, 10^?4 M ), were placed into the gingival crevices of alloxan‐induced diabetic rats. Gingival biopsies were taken 15 min later and then at 5‐min intervals up to 45 min and investigated by electron microscopy. Adherence and migration were observed in the rats with moderate diabetes 30 min after the application of casein. There was chemotaxis after 35 min of administration of the peptide FMLP. By 40 min neutrophils with pyknotic nuclei were observed. At 45 min neutrophils with a decreased number of granules were present. As the severity of the diabetes increased, the neutrophils degenerated and were structurally distorted. In the rats which had alloxan‐induced diabetes there was abnormal periodontal damage. This damage is thought to be related to dysfunctional neutrophils. These findings many contribute to an answer to the following question: why is there an apparent variability in the susceptibilty of periodontal breakdown in diabetics? Copyright © 2003 John Wiley & Sons, Ltd.