CHANGES OF THE PENETRATION STRENGTH OF THE LUMBAR VERTEBRAE TRABECULAR BONE OF ATHLETES DURING TRAINING

INTRODUCTION: Great static and dynamic load during athletic trainings with weightlifting exercises influence the skeleton, especially spine, of athletes. Some athletes feel pain in lumbar region during such athletic training. Changes in vertebrae bone tissue are mentioned as one of the reasons for pain (1). The osteopenetromethry method has been used for the evaluation of vertebra trabecular bone during the previous years (2,3). The purpose of this study was to examine the changes of vertebra penetration strength (PS) in lumbar region of athletes during the athletic training with weight-lifting exercises using this method. METHODS:120 athletes (aged 18 to 26) from different sports (Tab.1) were examined. We examined PS of 3 to 5 lumbar vertebrae on the 1st, 7th, 14th, 21st and 28th day of athletic training, according to the method described by Logins (3). RESULTS:The PS of lumbar vertebrae of the athlets on the 1st training day was from 4.2 MPa up to 5.1 MPa. On the 7th day of training the decrease from 17% to 35% of the initial value of PS was denoted. According to the level of PS decrease, we conditionally divided the athlets into two groups. The PS of the first group athlets was decreased for 20% of the initial value. The PS decrease of the second group of athlets exceeded 20% of the initial value (Tab.2) [Tab.2.] On the 14th day of athletic training’s the rehabilitation of the initial level of PS of lumbar vertebrae was denoted for the first group athletes and stayed the same during all the time of intensive load (28 days). For the second group of athletes during the time of intensive load the decrease of PS of lumbar vertebrae was denoted up to 2.7±0.38 MPa on the 28th day of athletic training. CONCLUSIONS: The results of our investigation prove that intensive physical load during athletic training’s with weight-lifting exercise of athletes causes changes to the structural organization of vertebral trabecular bone and bone mineral content. If the load exceeds the functional possibilities of spine, the remarkable changes of the vertebral trabecular bone strength take place in 7th day of training. REFERENCE: 1. Silva MJ.Gibson JA.(1997) Bone 21(2):191-199. 2. Hvid I. (1988) Clin Orthop.227: 210-221. 3. Logins V (1996) Mechanics of Composit.Materials 4:564-573

Reactogenicity of Biomaterials as Studied by Biochemical, Morphological and Ultrastructural Techniques

Reactogenicity is a characteristic of biocompatible materials that provokes the reparative and proliferative reaction of connective tissues, a compulsory stage of which is inflammation. Thus, reactogenicity studies should include experiments in vivo. A quantitative assessment of reactogenicity can be obtained by subcutaneous implantation of standard olive-shaped specimens covered by the biomaterial under study followed by biochemical, histological and scanning electron microscopical studies of the capsule developing around the implant. Reactogenicity of surgical threads is evaluated by semiquantitative histological analysis of the wound healing process after suture application. Biomaterial reactogenicity can be modified by changing the structure of the surface and its chemical characteristics, and in particular, by applying different biologically active substances including atrane-containing compounds. The reactogenicity indices suggested present the results of the interaction between the biomaterials and the cells

Social innovation between necessity and opportunity

The contribution of social innovation to the institutional change has been studied in the case of promoting healthy ageing. While major institutional change is well memorized by the present generation, the iterative approach to social innovation build up, and reaching the critical mass for a leap is viewed in the context of a specific region and social group. Selected types of social innovations are projected in their impact on societal challenges and institutional transformation potential

Kirurgija. Interna medicina. Medicinas bazes zinatnes. Stomatologija. Farmacija 2001. gada medicinas nozares petnieciska darba publikacijas

Abstracts in EnglishAvailable from Latvian Academic Library / LAL - Latvian Academic LibrarySIGLELVLatvi

Tannic acid mimicking dendrimers as small intestine submucosa stabilizing nanomordants

Chemical stabilization resulting in increased resistance to proteolytic degradation is one of the approaches in prevention of post-implantational aneurysm development in decellularized natural vascular scaffolds. Recently, tannic acid (TA) and tannic acid mimicking dendrimers (TAMD) have been suggested as potential stabilization agents for collagen and elastin. The aim of this work was to determine the stabilizing effects of TAMD on decellularized natural scaffolds. Vascular scaffolds fabricated from small intestine submucosa (SIS) and SIS plane sheets (Cook Biotech Inc.) were used. The biomechanical properties of the SIS vascular graft segments treated with TA and TAMD were tested. The effect of TAMD treatment on resistance to proteolytic degradation was evaluated by measuring biomechanical properties of TAMD stabilized and non-stabilized SIS specimens after incubation in collagenase solution. It was shown that treatment with TA as well as with TAMD increased the strength of tubular SIS as well as their resistance to proteolytic biodegradation manifested by preservation of biomechanical properties after collagenase treatment. Transmission electron microscopy demonstrated that treatment with TAMD increased the periodical pattern typical of collagen fiber ultrastructure as a result of the “mordant” effect. The possible collagen cross-linking effect of TAMD on SIS was investigated by differential scanning calorimetry (DSC). The treatment with TAMD induced a small, but detectable cross-linking effect, suggesting that TAMD do not establish extensive covalent cross links within the extracellular matrix but rather interact with collagen, thus rendering SIS scaffolds more resistant to proteolytic degradation

Structural Determinants of Material Properties of Heart Valve

Structural determinants of material properties of heart valv