[MICROECOLOGICAL CHANGES IN THE INTESTINE AND ITS EFFECT ON THE CONDITION OF HARD TISSUES OF TEETH IN ADOLESCENCE].

On the background of microecological changes in the gastrointestinal tract, mineral and protein metabolism is disrupted, biochemical changes occur in the phosphorus-calcium metabolism in the bones of the skeleton and hard tissues of the teeth. The aim of the research was to study the activity of the caries process, characterized by progressive decalcification, under conditions of microecological changes in the intestine and its effect on the processes of endogenous calcium assimilation in adolescence. Within the frames of the research 68 adolescents aged 11 to 17 years with various degrees of pathology of the gastrointestinal tract were examined. The data of the performed studies showed that in patients with more severe changes in the intestinal micro flora, the prevalence and intensity of dental caries are significantly higher (83.4% on average DMFT 5.0) than in adolescents with mild dysbiosis (71.8% DMFT 3.2% ), and in the patients with normal intestinal micro flora - the parameters were minimal. Estimating and comparing the interrelation between the incidence of caries and the presence of diseases of the gastrointestinal tract in adolescents, a directly proportional dependence of the DMF index on age was found, but the greatest increase in the individual level of incidence of dental caries (SIC) was observed in adolescents aged 14-16 (SIC=0,42) with severe gastrointestinal pathology GIT. Thus, significant changes in dental status detected in adolescents with pathology of the gastrointestinal tract confirm the validity of complex treatment and preventive dental care, considering the processes occurring in the body and the oral cavity, as well as the systematic, purposeful dental care and the allocation of patients with gastrointestinal pathology (GIT) in a separate group.

Direct inhibition of osteoblastic Wnt pathway by fibroblast growth factor 23 contributes to bone loss in chronic kidney disease.

Bone loss and increased fractures are common complications in chronic kidney disease. Because Wnt pathway activation is essential for normal bone mineralization, we assessed whether Wnt inhibition contributes to high-phosphorus-induced mineralization defects in uremic rats. By week 20 after 7/8 nephrectomy, rats fed a high-phosphorus diet had the expected high serum creatinine, phosphorus, parathyroid hormone, and fibroblast growth factor 23 (FGF23) levels and low serum calcium. There was a 15% reduction in tibial mineral density and a doubling of bone cortical porosity compared to uremic rats fed a normal-phosphorus diet. The decreases in tibial mineral density were preceded by time-dependent increments in gene expression of bone formation (Osteocalcin and Runx2) and resorption (Cathepsin K) markers, which paralleled elevations in gene expression of the Wnt inhibitors Sfrp1 and Dkk1 in bone. Similar elevations of Wnt inhibitors plus an increased phospho-ß-catenin/ß-catenin ratio occurred upon exposure of the osteoblast cell line UMR106-01 either to uremic serum or to the combination of parathyroid hormone, FGF23, and soluble Klotho, at levels present in uremic serum. Strikingly, while osteoblast exposure to parathyroid hormone suppressed the expression of Wnt inhibitors, FGF23 directly inhibited the osteoblastic Wnt pathway through a soluble Klotho/MAPK-mediated process that required Dkk1 induction. Thus, the induction of Dkk1 by FGF23/soluble Klotho in osteoblasts inactivates Wnt/ß-catenin signaling. This provides a novel autocrine/paracrine mechanism for the adverse impact of high FGF23 levels on bone in chronic kidney disease.

The anti-osteoporotic effect of Eurycoma Longifolia in aged orchidectomised rat model.

Osteoporosis in elderly men is becoming an important health issue with the aging society. Elderly men with androgen deficiency are exposed to osteoporosis and can be treated with testosterone replacement. In this study, Eurycoma longifolia (EL), a plant with androgenic effects, was supplemented to an androgen-deficient osteoporotic aged rat as alternative to testosterone. Aged 12 months old Sprague-Dawley rats were divided into groups of normal control (NC), sham-operated (SO), orchidectomised-control (OrxC), orchidectomised and supplemented with EL (Orx + El) and orchidectomised and given testosterone (Orx + T). After 6 weeks of treatment, serum osteocalcin, serum terminal C-telopeptide Type 1 collagen (CTX) and the fourth lumbar bone calcium were measured. There were no significant differences in the osteocalcin levels before and after treatment in all the groups. The CTX levels were also similar for all the groups before treatment. However, after treatment, orchidectomy had caused significant elevation of CTX compared to normal control rats. Testosterone replacements in orchidectomised rats were able to prevent the rise of CTX. Orchidectomy had also reduced the bone calcium level compared to normal control rats. Both testosterone replacement and EL supplementation to orchidectomised rats were able to maintain the bone calcium level, with the former showing better effects. As a conclusion, EL prevented bone calcium loss in orchidectomised rats and therefore has the potential to be used as an alternative treatment for androgen deficient osteoporosis.

Differential expression of IFN-gamma, IL-4, IL-10, and IL-1beta mRNAs in decalcified tissue sections of mouse lipopolysaccharide-induced periodontitis mandibles assessed by in situ hybridization.

To examine the role of T cell subgroups, Th1 and Th2, in the development of periodontitis, the expression of various cytokines was investigated in a mouse model of alveolar bone resorption using in situ hybridization (ISH) with digoxigenin-labeled oligonucleotides. When mice received repetitive injections with Escherichia coli lipopolysaccharide into the gingiva every 48 h, alveolar bone resorption was detectable after the fourth injection, reaching a maximum after the 13th injection. For the best performance of ISH, we first had to choose a decalcification protocol. Among various decalcification protocols, 10% EDTA (4 degrees C, 5-6 days) was the best for 28S rRNA staining. Positive cells for transcripts of interferon-gamma (Th1 product) were detected after the fourth injection, reaching a maximum after the tenth injection. A similar pattern was obtained for interleukin (IL)-10 mRNA (Th2 product) and IL-1beta, while the positive cell number reached a maximum after the 13th and 10th injections, respectively. The number of IL-4 mRNA (Th2 product)-positive cells remained low till the tenth injection, but increased thereafter. Consequently, we found that the population change from Th1 to Th2 in the inflammation site correlated with the transition from gingivitis to periodontitis, indicating differential roles of T cell subgroups in the development of periodontitis.

[De- and remineralization processes of the surface layer of the enamel in intact and pulp-extirpated teeth]. / Protsessy de- i remineralizatsii poverkhnostnogo sloia émali intaktnykh i depul'pirovannykh zubov.

Clinico-laboratory investigation of 61 intact teeth and 61 teeth after pulp extraction was performed, including in vivo acid enamel biopsy and intravital staining with 2% methylene blue solution. The regularities were established governing Ca and P efflux from superficial enamel layer of intact and pulp-extracted teeth into the acid solution with respect to age, group of the tooth and pulp extraction terms. The pulp extraction factor was investigated with special reference to the tooth acid resistance and its remineralization rate.

Hardness changes and mineral loss in enamel during the intra oral cariogenicity test in the presence of 0.125% EHDP with or without 0.1% F-.

The effects of a high EHDP concentration (0.125%) were measured under Intra Oral Cariogenicity Test (ICT) conditions in the presence or absence of F- (0.1%). EHDP as well as EHDP supplemented with F- inhibited the softening of enamel slabs to a similar extent as measured by microhardness. Measurements of the calcium and phosphate levels as a function of depth showed that the addition of F- to the EHDP solution further decreased mineral loss in the deeper layers. The results suggest that the inhibition of demineralization of the enamel by EHDP and F- is due to inhibition of acid production by microorganisms.

Calmodulin activity in corticosteroid-induced osteopenia.

A reproducible high-pressure liquid chromatography assay of calmodulin, a multifunctional calcium-dependent modulating protein, was developed for cartilage and bone by using cyclic nucleotide phosphodiesterase activity as the basis for standard curve determination. Calmodulin activity was then measured in rabbits that were made osteopenic by prednisolone injection in an effort to characterize in vivo cellular events. A significant rise in bone calmodulin levels was noted when this data was correlated with osteocyte and osteoblast content by quantitative histomorphometry. This suggests that calmodulin mediates steroid effects on the collagen matrix as well as on calcium homeostasis. Diminished calmodulin levels in weight-bearing cartilage of steroid-treated animals has as yet unresolved significance. Further characterization of calmodulin activity appears warranted in the study of osteopenic states at the subcellular level.

Mature osteocytes behaviour in a repletion period: the occurrence of osteoplastic activity.

The occurrence of osteoplastic activity in adult osteocytes from the femoral cortex of laying hens previously kept on a hypocalcaemic diet was studied after return of the animals to a calcium-rich alimentation. The following techniques were used: 1) tetracycline labelling of new calcifying matrix; 2) osteoid staining with alcian blue at pH 1.9 or toluidine blue at pH 3.1; 3) electron microscopic observations; 4) autoradiographic evaluation of (3H) proline uptake by osteocytes. Quantitative evaluation of (3H) proline uptake by osteocytes. Quantitative evaluation of the preparations consistently showed indication of osteoplastic activity in at least 20% of the osteocytes with relatively higher values in the metaphysis than in the diaphysis.

Prolonged weightlessness and calcium loss in man.

Data have been accumulated from a series of studies in which men have been subjected to weightlessness in orbital space flight for periods of up to 12 weeks. These data are used to predict the long term consequences of weightlessness upon the skeletal system. Space flight induced a loss of calcium which accelerated exponentially from about 50 mg/d at the end of 1 week to approx. 300 mg/d at the end of 12 weeks. The hypercalciuria reached a constant level within 4 weeks while fecal calcium losses continued to increase throughout the period of exposure. This apparent diminution of gastrointestinal absorptive efficiency was accompanied by a slight decline in the plasma level of parathyroid hormone and a slight elevation in the plasma level of calcium and phosphorus. Although losses in mineral from the calcaneus were closely correlated with the calcium imbalance, no changes were detected in the mineral mass of the ulna and radius. From the data presented it is concluded that the process of demineralization observed in space flight is more severe than would be predicted on the basis of observations in immobilized, bed rested, or paralyzed subjects. It is, moreover, suggested that the process may not be totally reversible.

Bone mineral analysis using single-energy computed tomography.

We present a new method for evaluating in vivo changes in bone mineralization in the peripheral skeleton, using computed tomography (CT). A set of bone mineralization indices are generated from numerous CT images of the patient's distal radius. The cross-sectional anatomy displayed by the CT scan allows for separate evaluation of the cortical and trabecular bone. Correction for possible drift of the CT number scale (Hounsfield scale) is achieved by scanning standard solutions of dipotassium hydrogen phosphate simultaneously with the forearm. Preliminary data indicate that this is a precise method for evaluating in vivo changes in bone mineralization.