Potential Relevance of Bioactive Peptides in Sports Nutrition

Bioactive peptides are physiologically active peptides mostly derived from proteins following gastrointestinal digestion, fermentation or hydrolysis by proteolytic enzymes. It has been shown that bioactive peptides can be resorbed in their intact form and have repeatedly been shown to have a positive effect on health-related parameters such as hypertension, dyslipoproteinemia, inflammation and oxidative stress. In recent years, there has been increasing evidence that biologically active peptides could also play an important role in sports nutrition. Current studies have shown that bioactive peptides could have a positive impact on changes in body composition and muscular performance, reduce muscle damage following exercise and induce beneficial adaptions within the connective tissue. In the following overview, potential mechanisms as well as possible limitations regarding the sports-related effect of bioactive peptides and their potential mechanisms are presented and discussed. In addition, practical applications will be discussed on how bioactive peptides can be integrated into a nutritional approach in sports to enhance athletic performance as well as prevent injuries and improve the rehabilitation process.

Reactions of Subcutaneous Connective Tissue to Mineral Trioxide Aggregate, Biodentine®, and a Newly Developed BioACTIVE Base/Liner

AIM

There is an increasing interest in the application of BioACTIVE materials to achieve hard tissue formation and maintain pulp vitality. Mineral trioxide aggregate (MTA) and Biodentine® are BioACTIVE materials used for pulp capping. Recently, dental researchers have produced BioACTIVE glass-incorporated light-curable pulp capping material. The study is aimed at evaluating the subcutaneous connective tissue reactions to MTA, Biodentine®, ACTIVA BioACTIVE Base/Liner. These materials were placed in polyethylene tubes and implanted into the dorsal connective tissue of Sprague Dawley rats. The presence of inflammation, predominant cell type, calcification, and thickness of fibrous connective tissue was recorded by histological examination 7, 30, and 60 days after the implantation procedure. Scores were defined as follows: 0 = none or few inflammatory cells, no reaction; 1 = <25 cells, mild reaction; 2 = 25 to 125 cells, moderate reaction; and 3 = ≥125 cells, severe reaction. Fibrous capsule thickness, necrosis, and formation of calcification were recorded. ANOVA and post hoc Dunnett's tests were used for statistically analyses (p < 0.05).

RESULTS

In terms of oedema, inflammation, fibrous capsule, and necrosis, no significant differences were found in any time period for any material. MTA and Biodentine® showed higher calcification than in the ACTIVA BioACTIVE on day 30, and the difference was statistically significant (p < 0.05). After 60 days, while calcification was not seen in the control group, it was observed in the test groups. There was a statistically significant difference between the control and the others.

CONCLUSION

All materials were well tolerated by the tissues in the 60-day evaluation period. One notable finding is the presence of dystrophic calcification in the connective tissue adjacent to the newly developed BioACTIVE Base/Liner material. Therefore, this new BioACTIVE Base/Liner material may be safely recommended to clinicians as a pulp capping material.

Antibacterial Effect of Curcumin against Clinically Isolated Porphyromonas gingivalis and Connective Tissue Reactions to Curcumin Gel in the Subcutaneous Tissue of Rats

The aim of this study was to find the antibacterial potential of curcumin against Porphyromonas gingivalis and connective tissue responses to curcumin gel in the subcutaneous tissue of rats. The sample consisted of subgingival plaque collected from patients with chronic periodontitis. The P. gingivalis clinically isolated strain was confirmed by anaerobic culture, morphology, biochemical tests (Vitek ANC Kit), and PCR (16S rDNA). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by incubation of twofold serial dilution of broth media containing curcumin (from 100 to 0.05 µg/ml) for 48 h at 37°C. Fifteen adult Wistar rats (3-4 months old) were used and randomly divided into three groups (negative control, positive control, and experimental groups). Tubes were implanted on the back skin (45 tubes). Rats were euthanized at 7, 30, and 60 days after surgical processes, and then the samples were taken and processed to achieve conventional hematoxylin and eosin-stained slides. The MIC and MBC of curcumin against clinically isolated P. gingivalis were 12 µg/ml. Curcumin gel caused moderate inflammatory reactions at 7 and 30 days, while at 60 days, it caused dramatic decline and resulted in a nonsignificant response. Besides, curcumin gel stimulated quick reepithelialization, fibroblast proliferation, and scarring through the formation of thick bundles of well-organized collagen fibers. Curcumin has an effective antibacterial action against clinically isolated P. gingivalis at low concentration (12 µg/ml), and it was regarded as the biocompatible material in the subcutaneous tissues.

Cardiotoxicity in African clawed frog (Xenopus laevis) sub-chronically exposed to environmentally relevant atrazine concentrations: Implications for species survival

The toxic effects of different atrazine concentrations on tadpoles and adult male African clawed frogs (Xenopus laevis) were assessed in a controlled laboratory environment following 90 days' exposure. The aim was to elucidate the danger of atrazine exposure on the cardiac tissue relative to its critical function of rhythmic contractility, fundamental for optimal blood circulation and homeostasis. Tadpoles and adult frogs were exposed to 0 μg/L (control), 0.01 μg L^-1, 200 μg L^-1 and 500 μg L^-1 concentrations of atrazine for 90 days. Mortality was concenration-dependent and significantly increased in juvenile group (77%, 43%, 23% and 0 respectively for 500 μg L^-1, 200 μg L^-1, 0.01 μg L^-1, and control group). While the mean juvenile heart area decreased concentration-dependently, adult frog mean heart area significantly increased in the 200 μg L^-1 group only and mean heart weight change was variable across all exposure levels. Light microscopy of hematoxylin and eosin (H&E) and Mallory-Heidenhain rapid one-step staining techniques on cardiac tissue sections of the juvenile and adult frogs revealed shrinkage of cardiac muscle cells into thin wavy myocytes. Additionally, disorganized branching of muscle fibres with reduced striations were observed in 0.01 μg L^-1 and 200 μg L^-1 but hypertrophied myocytes, thickened intensely staining myofibrils in the 500 μg L^-1 group in juvenile and adult frogs. Significant increase in the mean percentage area of connective tissue in all the treated groups (p < 0.036) were also recorded. Immunohistochemistry analysis showed decreased eNOS localization in cardiac tissue in 200 μg L^-1 and 500 μg L^-1 of both juvenile and adult group, suggestive of decreased cardiac contractility due to atrazine exposure. The results indicate that environmentally relevant atrazine concentrations cause significant mortality in tadpoles while concentrations ≥200 μg L^-1 adversely affect cardiac muscle morphology and may induce functional perturbations in cardiac tissue contractility and consequent dysfunction which generally may have an adverse impact on their survival and longevity.

Effects of mechanical stretching on the morphology of extracellular polymers and the mRNA expression of collagens and small leucine-rich repeat proteoglycans in vaginal fibroblasts from women with pelvic organ prolapse

To determine the effect of mechanical stretching load and the efficacy of postmenopausal estrogen therapy (ET) on pelvic organ prolapse (POP), vaginal fibroblasts isolated from postmenopausal women with or without POP were subjected to 0.1-Hz uniaxial cyclic mechanical stretching (CS) with 10% elongation and 10-8 M 17-β-estradiol (E2) treatment. We investigated the morphological characteristics of extracellular polymers using scanning electron microscopy (SEM) and monitored the mRNA expression of type I collagen (COL I) and type III collagen (COL III) as well as the small leucine-rich proteoglycan (SLRP) family members decorin (DCN), biglycan (BGN), fibromodulin (FMO), and lumican (LUM), using real-time quantitative polymerase chain reaction (RT-PCR). Using SEM, certain viscoelastic polymers were found to be randomly distributed among fibroblasts, which for normal fibroblasts formed clusters of plum flower-like patterns under static-culture conditions and resembled stretched strips when stretched in culture, whereas polymers among POP fibroblasts resembled stretched strips under static-cultured conditions and presented broken networks when stretched in culture. RT-PCR revealed that COL I, DCN, BGN, FMO, and LUM mRNA expression was significantly higher in POP than in normal fibroblasts under static-culture condition. Following CS, COL I and BGN mRNA expression was significantly up-regulated in normal fibroblasts, and DCN and FMO mRNA expression was down-regulated in POP fibroblasts. Following concomitant CS and E2 treatment, significantly elevated COL I and DCN mRNA expression was observed in normal fibroblasts, and significantly elevated COL I and BGN mRNA expression was observed in POP fibroblasts. COL III mRNA expression was not significantly different between the POP and normal group, and CS did not significantly affect expression in either group, though COL III was down-regulated in normal fibroblasts concomitantly treated with E2 and CS. We conclude that the morphological distribution of extracellular polymers in POP fibroblasts exhibited higher sensitivity and lower tolerance to stretching loads than do normal fibroblasts. These mechanical properties were further reflected in the transcription of COL I. Defects in the compensatory function of BGN for DCN and LUM for FMO exist in POP fibroblasts, which further affect the structure and function of COL I in response to stretching load, ultimately resulting in abnormal reconstruction of pelvic supportive connective tissues and the occurrence of POP. ET can maintain stretching-induced elevations in COL I and DCN transcription in healthy women and improve stretching-induced COL I, DCN, BGN, and FMO transcriptional changes in POP women to prevent and improve POP. Only down-regulated COL III transcription was observed upon concomitant CS and E2 treatment in normal fibroblasts, which suggests that the tensile strength, not the elasticity, of the supportive connective tissues is damaged in POP and that the higher tensile strength induced by ET in healthy fibroblasts prevents POP. These findings confirm the role of higher sensitivity and lower tolerance to mechanical stretching in the pathogenesis of POP and further provide evidence supporting the use of ET to prevent and inhibit POP in postmenopausal women.

Proteolytic Nanoparticles Replace a Surgical Blade by Controllably Remodeling the Oral Connective Tissue

Surgical blades are common medical tools. However, blades cannot distinguish between healthy and diseased tissue, thereby creating unnecessary damage, lengthening recovery, and increasing pain. We propose that surgical procedures can rely on natural tissue remodeling tools-enzymes, which are the same tools our body uses to repair itself. Through a combination of nanotechnology and a controllably activated proteolytic enzyme, we performed a targeted surgical task in the oral cavity. More specifically, we engineered nanoparticles that contain collagenase in a deactivated form. Once placed at the surgical site, collagenase was released at a therapeutic concentration and activated by calcium, its biological cofactor that is naturally present in the tissue. Enhanced periodontal remodeling was recorded due to enzymatic cleavage of the supracrestal collagen fibers that connect the teeth to the underlying bone. When positioned in their new orientation, natural tissue repair mechanisms supported soft and hard tissue recovery and reduced tooth relapse. Through the combination of nanotechnology and proteolytic enzymes, localized surgical procedures can now be less invasive.

Successive Onset of Molecular, Cellular and Tissue-Specific Responses in Midgut Gland of Littorina littorea Exposed to Sub-Lethal Cadmium Concentrations

Cadmium (Cd) is one of the most harmful metals, being toxic to most animal species, including marine invertebrates. Among marine gastropods, the periwinkle (Littorina littorea) in particular can accumulate high amounts of Cd in its midgut gland. In this organ, the metal can elicit extensive cytological and tissue-specific alterations that may reach, depending on the intensity of Cd exposure, from reversible lesions to pathological cellular disruptions. At the same time, Littorina littorea expresses a Cd-specific metallothionein (MT) that, due to its molecular features, expectedly exerts a protective function against the adverse intracellular effects of this metal. The aim of the present study was, therefore, to assess the time course of MT induction in the periwinkle’s midgut gland on the one hand, and cellular and tissue-specific alterations in the digestive organ complex (midgut gland and digestive tract) on the other, upon exposure to sub-lethal Cd concentrations (0.25 and 1 mg Cd/L) over 21 days. Depending on the Cd concentrations applied, the beginning of alterations of the assessed parameters followed distinct concentration-dependent and time-dependent patterns, where the timeframe for the onset of the different response reactions became narrower at higher Cd concentrations compared to lower exposure concentrations.

[Histomorphometric evaluation of ridge preservation after molar tooth extraction]

OBJECTIVE

To evaluate bone formation in human extraction sockets with absorbed surrounding walls augmented with Bio-Oss and Bio-Gide after a 6-month healing period by histologic and histomorphometric analyses.

METHODS

Six fresh molar tooth extraction sockets in 6 patients who required periodontally compromised moral tooth extraction were included in this study. The six fresh extraction sockets were grafted with Bio-Oss particle covered with Bio-Gide. The 2.8 mm×6.0 mm cylindric bone specimens were taken from the graft sites with aid of stent 6 months after the surgery. Histologic and histomorphometric analyses were performed.

RESULTS

The histological results showed Bio-Oss particles were easily distinguished from the newly formed bone, small amounts of new bone were formed among the Bio-Oss particles, large amounts of connective tissue were found. Intimate contact between the newly formed bone and the small part of Bio-Oss particles was present. All the biopsy cylinders measurement demonstrated a high inter-individual variability in the percentage of the bone, connective tissues and Bio-Oss particles. The new bone occupied 11.54% (0-28.40%) of the total area; the connective tissues were 53.42% (34.08%-74.59%) and the Bio-Oss particles were 35.04% (13.92%-50.87%). The percentage of the particles, which were in contact with bone tissues, amounted to 20.13% (0-48.50%).

CONCLUSION

Sites grafted with Bio-Oss particles covered with Bio-Gide were comprised of connective tissues and small amounts of newly formed bone surrounding the graft particles.

Connective Tissue Metabolism and Gingival Overgrowth

Gingival overgrowth occurs mainly as a result of certain anti-seizure, immunosuppressive, or antihypertensive drug therapies. Excess gingival tissues impede oral function and are disfiguring. Effective oral hygiene is compromised in the presence of gingival overgrowth, and it is now recognized that this may have negative implications for the systemic health of affected patients. Recent studies indicate that cytokine balances are abnormal in drug-induced forms of gingival overgrowth. Data supporting molecular and cellular characteristics that distinguish different forms of gingival overgrowth are summarized, and aspects of gingival fibroblast extracellular matrix metabolism that are unique to gingival tissues and cells are reviewed. Abnormal cytokine balances derived principally from lymphocytes and macrophages, and unique aspects of gingival extracellular matrix metabolism, are elements of a working model presented to facilitate our gaining a better understanding of mechanisms and of the tissue specificity of gingival overgrowth.

Edema in Oral Mucosa after LPS or Cytokine Exposure

Lowering of interstitial fluid pressure (Pif) is an important factor that explains the rapid edema formation in acute inflammation in loose connective tissues. Lipopolysaccharide (LPS) and the pro-inflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) are pathogenetic in gingivitis. To test if these substances induce lowering of Pif in rat oral mucosa, we measured Pif with a micropuncture technique. IL-1β and TNF-α caused lowering of Pif, whereas LPS induced an immediate increase in Pif, followed by lowering after 40 min. Measurements of fluid volume distribution showed a significant change in interstitial fluid volume (Vi) 1.5 hr after LPS exposure as Vi changed from 0.41 ± 0.02 to 0.51 ± 0.03 mL/g wet weight ( p < 0.05), confirming edema. These findings show that LPS, IL-1β, and TNF-α induce lowering of Pif in the rat oral mucosa and contribute to edema formation in LPS-induced gingivitis.

Histopathological effect and stress response of mantle proteome following TBT exposure in the Hooded oyster Saccostrea cucullata

Tributyltin (TBT), an environmental pollutant in marine ecosystems, is toxic to organisms. Although contamination by and bioaccumulation and toxicity of this compound have been widely reported, its underlying molecular mechanisms remain unclear. In the present study, we exposed the Hooded oyster Saccostrea cucullata to TBT to investigate histopathological effects and proteome stress response. Animals were exposed to three TBT sub-lethal concentrations, 10, 50 and 150 μg/l for 48 h. TBT produced stress leading to histopathological changes in oyster tissues including mantle, gill, stomach and digestive diverticula. TBT induced mucocyte production in epithelia and hemocyte aggregation in connective tissue. Cell necrosis occurred when exposure dosages were high. Comparative proteome analyses of mantle protein of oysters exposed to 10 μg/l and control animals were analyzed by a 2-DE based proteomic approach. In total, 32 protein spots were found to differ (p < 0.05). Of these, 17 proteins were identified which included 14 up-regulated and 3 down-regulated proteins. TBT induced the expression of proteins involved in defensive mechanisms (HSP-78, HSP-70, aldehyde dehydrogenase and catalase), calcium homeostasis (VDAC-3), cytoskeleton and cytoskeleton-associated proteins, energy metabolism and amino acid metabolism. Our study revealed that TBT disturbs calcium homeostasis via VDAC-3 protein in mantle and this probably is the key molecular mechanism of TBT acting to distort shell calcification. Moreover, proteins involved in cell structure (tubulin-alpha and tubulin-beta) and protein synthesis were reduced after TBT exposure. Additionally, differential proteins obtained from this work will be useful as potential TBT biomarkers.

Preliminary Evaluation of Platelet Rich Fibrin-Mediated Tissue Repair in Immature Canine Pulpless Teeth

OBJECTIVE

To evaluate the use of platelet-rich fibrin (PRF) in the regenerative therapy of immature canine permanent teeth.

METHODS

Eight immature premolars of beagle dogs were pulp extracted and cleaned with irrigation, then divided into two groups of empty root canals and those filled with a PRF clot. All of the eight premolars were sealed with mineral trioxide aggregate and glass ionomer cement. Two premolars were left naturally grown as a positive control. The root development was assessed radiographically and histologically after 12 weeks.

RESULTS

The radiological findings showed greater increases in the thickness of lateral dentinal wall in the PRF group than in the vacant group. Histologically, dental-associated mineral tissue, connective tissue, and bone-like mineral tissue grew into the root canals independent of PRF clot use. The PRF was able to increase the thickness of dental-associated mineral tissue. However, the vital tissue differed from the pulp dentin complex.

CONCLUSION

Our study demonstrated the feasibility of using PRF-mediated regenerative therapy in pulpless immature teeth for improving tissue repair.

Budesonide-Dependent Modulation of Expression of Macrophage Migration Inhibitory Factor in a Polyposis Model: Evidence for Differential Regulation in Surface and Glandular Epithelia

Macrophage migration inhibitory factor (MIF) is a counterregulatory lymphokine for glucocorticoid action within the immune system. To provide further insights into the way expression of pleiotropically acting MIF is modulated by glucocorticoids, we investigated the influence of the glucocorticoid budesonide on the level of expression of MIF in a model of human nasal polyposis by quantitative immunohistochemical analysis. Ten nasal polyps obtained from surgical resection were maintained for 24 hours in the presence of 3 budesonide concentrations: 10, 50, and 250 ng/mL. As quantitatively demonstrated by computer-assisted microscopy, 50 ng/mL induced an increase in MIF expression in the surface epithelium and a decrease in MIF expression in the glandular epithelium. At the 250 ng/mL dose, the inverse effect was induced. Evidently, surface and glandular epithelia react nonuniformly to the glucocorticoid regarding MIF presence, adding dependence on the cell type to the regulatory network.

[THE ROLE OF TRANSFORMING GROWTH FACTOR-B IN IMMUNOPATHOGENESIS OF DISEASES OF CONNECTIVE TISSUE]

The recent studies of molecular physiology of fibrillin and pathophysiology of inherent disorders of structure and function of connective tissue such as dissection and aneurysm of aorta, myxomatously altered cusps and prolapses of mitral valve, syndrome of hyper-mobility of joints, demonstrated that important role in development of these malformations play alterations of transfer of signals by growth factors and matrix cellular interaction. These conditions under manifesting Marfan's syndrome can be a consequence of anomalies of fibrillin-1 which deficiency unbrakes process of activation of transforming growth factor-β (TGFβ). The involvement of TGFβ in pathogenesis of Marfan's syndrome permits consider antagonists of angiotensin-transforming enzymes as potential pharmaceuticals in therapy of this disease. The article presents analysis of publications' data related to this problem.

[THE EFFECT OF EXOGENOUS MELATONIN ON BONE REMODELING]

It was investigated in spring 28-day experiment the administration of pharmacological doses (5 mg/kg) of melatonin to 3-month male rats with high and low levels of energy metabolismat remodeling of bone tissue. It was shown the decrease in activity of osteoblast and increase of osteoclast activity regardless of energy metabolism intensity, increase in concentration of glycosaminoglycans and free amino acids. This indicates the inhibition of physiological bone remodeling and helps to maintain the integrity of the organic matrix and the inorganic component of the fixation of the connective tissue - hydroxyapatite crystals.

[EFFICIENCY OF COCARNIT IN COMPLEX THERAPY OF PATIENTS WITH SYSTEM DISEASES OF CONNECTING FABRIC WITH DEFEAT OF MYOCARDIUM AND DISPLAYS OF CARDIAC INSUFFICIENCY]

In clinical trial included 41 patient with clinic-instrumental dates, which said about myocardium dysfunction and system diseases of connecting fabric and displays of CCI I-III of functional class (FC). Including of complex metabolic drug Cocarnit in standard therapy of systemdiseases of connecting fabric was instrumental in more expressed clinical improvement of patientsclinical dates in 15 days of supervision: a weakness diminished on 66.67%, shortbreathing at the insignificant physical loading--on 23.81%, at the ordinary physical loading--on 47.62%, at the megascopic physical loading--on 19.05%, pain in area of heart--on 42.85%, there are interruptions in-process heart--on 28.57%, oedematousness of shins--on 57.14%, sense of numbness, burning, sensitiveness to cold of extremities--on 57.14%. Quantity of patients with III FC diminished on 5 (23.81%), in a control group--on 2 (10%). It implementation of test with the 6-minute walking more expressed increase of the overcame distance is set for the patients of basicgroup--on 15.46% as compared to a control group--on 7.01%. Cocarnit patients estimatedpositively; side effects with subsequent abolition of drug, were not. Laboratory indexes (AlAT, AsAT, bilirubin, kreatinine, haemoglobin) at the end of trial did not change considerably, that confirmed good bearableness of drug.

[INFLUENCE OF QUINAPRIL IN COMBINATION WITH ANGIOLINE ON THE CONNECTIVE TISSUE COMPONENTS IN THE RATS SERUM WITH EXPERIMENTAL HYPERTENSION]

One of the most active inhibitors angiotensin-converting enzyme is quinapril that has a high affinity for tissue ACE, improves endothelial vasodilation, has a wide therapeutic range and beneficient influence on heart rate. A new biological active compound with antioxidant action that has endothelioprotective, cardioprotective, antiischemic action is angiolin. In experimental arterial hypertension in the animals blood serum the activity of collagenase, the content of free and protein connecting fractions of hydroxyproline and indicators that reflect the metabolism of glycosaminoglycans have been increased. Angiolin increases the activity of collagenase free and protein connecting fractions of hydroxyproline comparing to control. Concentration glycosoaminoglycan (GAG) also exceeds the standard data. Quinapril has similar to angiolin action directed effect to the connective tissue components, though losing as proteinconecting of hydroxiproline action. Cooperative application quinapril with angioline most effectively influence the metabolic processes stabilization in experimental animals.

[Reparative regeneration of connective tissue structures of mammals under antioxidant therapy conditions]

The influence of administration of the antioxidant complexes consisting of nonenzymatic antioxidants (alpha-tocopherol acetate preparation) and enzymatic antioxidants (ceruloplasmin) has been studied in rabbits with experimental arthritis. The introduction of alpha-tocopherol acetate (at a daily dose of 4 mg) improved metabolic processes in the organism (decreased in the rate of erythrocyte precipitation, total leukocytes and their stub and segmental forms; increased in erythrocyte count; reduced the glycosaminoglycan content as determined from uronic acid and hexose level; decreased ceruloplasmin activity and malonic dialdehyde level ion blood serum, all at p < 0.05), thus favoring reduction in the total activity of the inflammatory process as judged from hematological and biochemical data. Intra-articular introduction of ceruloplasmin (1.5 mg/kg, once per week) positively influenced the state of joint structures in damaged knee joints of the animals: decreased the activity of ceruloplasmin (from 5.28 ± 0.06 to 3.94 ± 0.01 AU), and malonic dialdehyde level (0.18 ± 0.02 to 0.08 ± 0.01 μM) in the articular fluid (all at p < 0.05). These effects are probably related to the elimination of inefficiency of the antioxidant system in the synovial medium, thus preventing inflammatory destruction of articular tissues, hindering the development of pannus, and assisting the activation of reparative regeneration of connective tissue structures.

[MORPHOFUNCTIONAL STATE OF THE THYROID GLAND AFTER EXPOSURE TO MELATONIN]

Morphofunctional state of the thyroid gland (TG) of young rats after exposure of exogenous melatonin in the spring and autumn periods was investigated. Exogenous melatonin (Unipharm Inc., USA) was administered to experimental group of animals daily at a dose 5 mg/kg. The duration of the experiment was 28 days. It was shown an increase of the cross-section area of follicles by 31% and colloid by 30% (in spring), reduction of the area of follicle epithelium by 12% (in autumn), an increase in the follicle internal diameter and a decline in the thyroid epithelium height by 12% (in autumn) in TG of experimental groups rats. Also it was shown a decline of follicle-colloid index and growth of colloid accumulation index, reduction amount of interfollicular islets. The introduction of melatonin in the spring period brought down the amount of connecting tissue elements. Melatonin introduction in the autumn period reduced the thickness of connective tissue trabecules in TG. The introduction of melatonin in the spring period resulted in more substantial changes in the structure of TG, as compared to an autumn experiment. Thus, melatonin administered both in the spring and in the autumn periods reduces the functional activity and physiological regeneration of TG.

[IN VIVO EVALUATION OF POLYCAPROLACTONE-HYDROXYAPATITE SCAFFOLD BIOCOMPATIBILITY]

Biocompatibility is one of the main and very important properties for scaffolds. The aim of the present study was to investigate cells population dynamics in vivo in the process of original polycaprolactone-hydroxyapatite scaffold colonization, as well as tissue reactions to the implantation to assess the biocompatibility of the matrix. It has been found that tissue reactive changes in white rats subside completely up to the 21st day after subcutaneous polycaprolactone-hydroxyapatite scaffold implantation. Matrix was actively colonized by connective tissue cells in the period from the 7th to the 21st day of the experiment. However, intensive scaffold vascularization started from the 14th day after implantation. These findings suggest a high degree of the polycaprolactone-hydroxyapatite scaffold biocompatiblilitye.

Effects of caffeic acid phenethyl ester on wound healing in calvarial defects

OBJECTIVE

The aim of this study is to analyze histologically the effect of CAPE on bone healing of Critical Size Defect (CSD) in rat calvaria.

STUDY DESIGN

Thirty-two 3-month-old male rats were used. The animals were randomly divided into four groups. Group A received isotonic saline solution, Group B received CAPE (50 mmol/kg) locally, Group C received CAPE (100 mmol/kg) locally and Group D received CAPE (10 mmol/kg/day i.p. for 28 days) systematically. A 5-mm diameter calvarial defect was created in the right side of the parietal bone without damaging the underlying dura mater. Twenty-eight days after the surgery, all the animals were sacrificed. The original defect area was removed from the animal's calvarium bone en bloc. Beginning at the center of the surgical defect, serial sections of 6 µm thick were cut longitudinally. The sections were stained with hematoxylin and eosin for analysis under a light microscope. The sections were analyzed for the presence of inflammatory infiltrate, connective tissue formation and new bone formation. Computer-assisted histomorphometic measurements were carried out with an automated image analysis system.

RESULTS

The total new bone areas were significantly greater in group D than in all groups and group C was statistically insignificant from the other groups (p < 0.05). Group B had a greater, but not statistically significant (p > 0.05), amount of total regenerated bone area than the control group.

CONCLUSION

The results indicate that 100 mmol/kg topical and 10 mmol/kg/day systemic application of CAPE increases bone healing, especially with systemic application.

Update on the possible nutritional importance of silicon

Convincing evidence that silicon is a bioactive beneficial trace element continues to accumulate. The evidence, which has come from human, animal, and in vitro studies performed by several laboratories, indicate that silicon in nutritional and supra nutritional amounts promotes bone and connective tissue health, may have a modulating effect on the immune or inflammatory response, and has been associated with mental health. A plausible mechanism of action for the beneficial effects of silicon is the binding of hydroxyl groups of polyols such that it influences the formation and/or utilization of glycosaminoglycans, mucopolysaccharides, and collagen in connective tissue and bone. In addition, silicon may affect the absorption, retention or action of other mineral elements (e.g., aluminum, copper, magnesium). Based on findings from both animal and human experiments, an intake of silicon of near 25mg/d would be a reasonable suggestion for an adequate intake that would assure its nutritional benefits. Increased intakes of silicon through consuming unrefined grains, certain vegetables, and beverages and cereals made from grains should be recognized as a reasonable dietary recommendation.

Leucine supplementation accelerates connective tissue repair of injured tibialis anterior muscle

This study investigated the effect of leucine supplementation on the skeletal muscle regenerative process, focusing on the remodeling of connective tissue of the fast twitch muscle tibialis anterior (TA). Young male Wistar rats were supplemented with leucine (1.35 g/kg per day); then, TA muscles from the left hind limb were cryolesioned and examined after 10 days. Although leucine supplementation induced increased protein synthesis, it was not sufficient to promote an increase in the cross-sectional area (CSA) of regenerating myofibers (p > 0.05) from TA muscles. However, leucine supplementation reduced the amount of collagen and the activation of phosphorylated transforming growth factor-β receptor type I (TβR-I) and Smad2/3 in regenerating muscles (p < 0.05). Leucine also reduced neonatal myosin heavy chain (MyHC-n) (p < 0.05), increased adult MyHC-II expression (p < 0.05) and prevented the decrease in maximum tetanic strength in regenerating TA muscles (p < 0.05). Our results suggest that leucine supplementation accelerates connective tissue repair and consequent function of regenerating TA through the attenuation of TβR-I and Smad2/3 activation. Therefore, future studies are warranted to investigate leucine supplementation as a nutritional strategy to prevent or attenuate muscle fibrosis in patients with several muscle diseases.

[INFLUENCE OF HYPERICUM PERFORATUM L. HERB POLYPHENOLS PREPARATION WITH MINERALS ON THE STATE OF PERIODONTAL CONNECTIVE TISSUE MATRIX OF RATS IN CONDITION OF PERIODONTITIS MODELING]

In experiments on 22 white 1.5-month-old rats-males there were studied influence of Hypericum perforatum L. and minerales from Dyovit® on periodont's tissues under periodontits modelling. Examined preparation normalizes level of glicosaminoglicanes in gum, but did not completely show protective effects relative to collagen's fraction. In periodont's bone preparation decreases resorbrtion; increases activity of AlP and in the same time normalizes activity of AcP.

Sodium metabisulphite, a preservative agent, decreases the heart capillary volume and length, and curcumin, the main component of Curcuma longa, cannot protect it

Sodium metabisulphite is used as an antioxidant agent in many pharmaceutical formulations. It is extensively used as a food preservative and disinfectant. It has been demonstrated that sulphite exposure can affect some organs. Curcumin, the main element of Curcuma longa, has been identified to have multiple protective properties. The present study extends the earlier works to quantitative evaluation of the effects of sulphite and curcumin on the heart structure using stereological methods. In this study, 28 rats were randomly divided into four experimental groups. The rats in groups I to IV received distilled water (group I), sodium metabisulphite (25 mg/ kg/day) (group II), curcumin (100 mg/kg/day) (group III), and sodium metabisulphite+curcumin (group IV), respectively, for 8 weeks. The left ventricle was subjected to stereological methods to estimate the quantitative parameters of the myocardium. A 20 % decrease was observed in the total volume of ventricular tissue in the sulphite-treated animals compared to the distilled water treatment (P < 0.02). Also, the volume and length of the capillaries were reduced by 43 % on average in the sulphite-treated rats in comparison to the distilled water-treated animals (P < 0.02). However, no significant change was seen in the mean and total volume of the myocardium and the cavity and diameter of the capillaries after sulphite ingestion. Treatment with curcumin did not protect the animals against the structural changes of the ventricle. Sulphite, as a preservative food agent, reduced the length and volume of the ventricular capillaries and curcumin could not protect them.

Antifibrotic activity of hyaluronidase immobilized on polyethylenoxide under conditions of bleomycin-induced pneumofibrosis

Hyaluronidase immobilized on polyethylenoxide obtained by electron bean synthesis was administered intranasally and intravenously to C57Bl/6 mice after intratracheal bleomycin and the enzyme effects on the development of pneumofibrosis in animals were studied. Intranasal immobilized hyaluronidase prevented connective tissue growth in the lungs exposed to bleomycin and virtually did not modulate the infiltration of the alveolar and alveolar duct interstitium by inflammatory cells (lymphocytes, macrophages, neutrophils, plasma cells). The antifibrotic effect developed sooner after intranasal inoculation of immobilized hyaluronidase and was more pronounced than after intranasal native hyaluronidase. Intravenous injection of immobilized hyaluronidase did not modify the inflammatory process and deposition of collagen fibrils in the lung parenchyma in pneumofibrosis.

[Morphological tissue changes after the implantation of a biodegradable material on collagen basis]

The objective of this study was to examine the peculiarities of tissue reactions during the degradation of "Collost" bioplastic material on the collagen basis with completely preserved fibrous structure, after its implantation into the bone tissue defect. The defect in bone tissue sized 1-2 mm x 3-5 mm was created in tibial condyle. The study was performed on 24 Wistar rats using light microscopic methods. The tissue reactions were studied at different time intervals (1, 2, 6 and 12 months) after the implantation of collagenic material. It was found that after the implantation, the material became impregnated with blood, and due to fibrin, densely adhered to the damaged tissues. Further, the cells were found to migrate along the blood clot into its depth from the surrounding tissues. These were primarily the fibroblasts which were located in a network of fibers and started to absorb collagen from a surrounding material and to synthesize new collagen. Gradually, the collagenic material became similar to a cell-containing network. The volume of the newly synthesized collagen increased, and after some time all the foreign material was absorbed by fibroblasts and replaced with connective tissue. After 1 year, a large "Collost" fragment was completely degraded and replaced by loose connective tissue. The implantation of a collagenic material did not stimulate the formation of a delimiting connective tissue capsule

[Experimental assessment of biodegradable polyglycolic and polylactic acid polymers for medical use]

Interrelations of biodegradable poliglicolic and polilactic acid polymers in various proportions implanted in standardized bone defects were evaluated in animal model with 40 Wister line rats. During 10 month follow-up period bone capsule surrounded all implants, but timing of bone formation and bone quality varied significantly being optimal in LactoSorb group. Destructive features of polymers were also seen in implant-bone contact area defined as inflammation, fibrous tissue formation and cell dystrophy.

Assessing the biocompatibility of a dental composite product

OBJECTIVE

The purpose of the study was to assess the biocompatibility of a composite material considering the reaction caused at the implant site during 21 days by daily observing the subjects' behavior as well as by macroscopic examination and histological examination upon expiry of the testing period.

MATERIALS AND METHODS

We performed the tolerance test by implant of the composite material Dualcim. The implant test was made on two species of lab animals, Guinea pigs and Wistar rats in two versions: subcutaneous implant and intramuscular÷perimuscular implant.

RESULTS

After a 21 days period, when the implant was in direct contact with the tissue, no change of the shape and consistency, color or surface of the implant occurred. Around the implants, the biocompatibility was kept under physiological limits.

CONCLUSIONS

The product, in the structure and shape presented, could be easily placed under good conditions, both at the level of the subcutaneous tissue and at inter-muscular level. In case of both species and in all subjects, the histological exam proved a favorable development of the relationship between the implant body and the placing site.

The impact of triamcinolone acetonide in early breast capsule formation in a rabbit model

BACKGROUND

The etiology and clinical treatment of capsular contracture remain unresolved as the causes may be multifactorial. Triamcinolone acetonide applied in the pocket during surgery was reported to be ineffective in prevention of capsular contracture. However, if injected 4-6 weeks after surgery or as a treatment for capsular contracture, decreased applanation tonometry measurements and pain were observed. It was assumed that intraoperative application of triamcinolone was not effective because its effect does not last long enough. However, betadine, antibiotics, and fibrin were found to be effective in preventing capsular contracture with intraoperative applications and are more effective in the early phases of wound healing than in later stages. The role of triamcinolone acetonide in capsule formation is unknown. The purpose of this study was to determine if triamcinolone acetonide modulates breast capsule formation or capsular contracture in the early phases of wound healing in a rabbit model.

METHODS

Rabbits (n=19) were implanted with one tissue expander and two breast implants and were killed at 4 weeks. Implant pocket groups were (1) Control (n=10) and (2) Triamcinolone (n=9). Pressure/volume curves and histological, immunological, and microbiological evaluations were performed. Operating room air samples and contact skin samples were collected for microbiological evaluation.

RESULTS

In the triamcinolone group, a decreased capsular thickness, mild and mononuclear inflammation, and negative or mild angiogenesis were observed. There were no significant differences in intracapsular pressure, fusiform cell density, connective tissue, organization of collagen fibers, and microbiological results between the groups. There was no significant difference in the dialysate levels of IL-8 and TNF-α, but correlation between IL-8 and TNF-α was observed.

CONCLUSION

Triamcinolone acetonide during breast implantation influences early capsule formation and may reduce capsular contracture.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors at www.springer.com/00266.

[Comparative morphology of tissues when using polypropylene and polytetrafluoretilen prostheses]

The synthetic mesh is widely used for treatment of hernias. We conducted a comparative study of the morphological pattern of inflammation, the cellular composition of tissues and dynamics of scar formation in mice when using implants "Esfil" and "Unifleks" under influence of single and double injection of cultured fibroblast and without such injection to the region of stents location. A more pronounced inflammatory reaction during the study period of investigation was observed in the case of "Esfil". In the late period of the study, a higher percentage of fibroblasts was observed in the case of the prosthesis "Unifleks" compared to the prosthesis "Esfil". Injection of cultured fibroblasts modifies the curve of the dynamics of the inflammatory process by making it smoother in the case of both prostheses. So, more preferred is the use of prostheses "Unifleks".

Effect of local nifedipine administration on rat gingiva

BACKGROUND

Nifedipine, a calcium channel-blocking agent, has been associated with gingival enlargement in humans. This enlargement has also been successfully established in animal models. Previous investigators have administered nifedipine through a systemic route, most commonly by oral intake. The aim of the present study was to measure the effects of nifedipine administered directly into rat gingival interproximal papillae.

METHODS

Twenty-four adult female rats were assigned to three groups. Each animal received a series of three injections, one week apart; each injection was placed directly into the interdental papilla of the maxillary and mandibular central incisors. Group 1 (control) received only saline. Group 2 received a low (10 microg/ml) concentration of nifedipine, while Group 3 received a higher concentration (500 microg/ml). One week after the last series of injections, gingival specimens were harvested from the injection site and prepared for histological and immunocytochemical analyses.

RESULTS

Specimens from Group 3 displayed a significantly greater number of ED2-positive cells compared to the other two groups. Specimens from Group 2 showed a significantly higher mean count of positive cells compared to Group 1. Collectively, our data suggest that repeated local injections of 10 microg/ml and 500 microg/ml nifedipine each elicit an inflammatory response in the gingival connective tissue.

CONCLUSIONS

Immunocytochemical analysis revealed dose-dependent increases of resident tissue macrophages in rats receiving nifedipine (p<0.005). An increased inflammatory infiltrate also was observed via routine histology. Gross macroscopic changes consistent with gingival enlargement were not observed.

[Correction of a connective tissue dysplasia in the treatment of postoperative abdominal hernias]

There were analyzed the results of treatment of 112 patients, suffering postoperative abdominal hernia, in whom the anterior abdominal wall alloplasty was performed as well as postoperative pathogenetically substantiated complex therapy, taking into account the presence of a connective tissue dysplasia syndrome (CTDS) and the early and late postoperative complications prophylaxis. The peculiarities of postoperative period course and late follow-up results were studied up. Phenotypic features of CTDS were revealed in 53 (47.3%) patients, immunohistochemical features of a connective tissue dysplasia (a failed collagen type I and III ratio, manifested by increase of a collagen type III fibers quantity in 3 or more times) were revealed in 78 (69.6%) patients, in whom the processes of a collagen and its supermolecular formations synthesis were stimulated, using a magnesium orotate (Magnerot), which was prescribed in 1 g dose twice a day during 4 - 6 weeks. Application of composite nets, owing big pores, in a complex with a postoperative pathogenetically substantiated therapy conduction have positively influenced the disease course and the late follow-up results achieved.

Reaction of rat connective tissue to Mineral Trioxide Aggregate and Diaket

BACKGROUND

The aim of this study was to compare the reaction of rat connective tissue to two root-end filling materials: white Mineral Trioxide Aggregate (WMTA) and Diaket.

METHODS

Each of the materials was placed in dentine tubes and implanted subcutaneously in the dorsal connective tissue of 21 Wistar albino rats. Tissue biopsies were collected 7, 30, and 60 days after the implantation procedure. The specimens were processed and stained with hematoxylin and eosin and examined microscopically. After determining inflammatory cell numbers in sections from each specimen, inflammatory reaction scores were defined as follows: 0; no or few inflammatory cells (no reaction), 1; less than 25 cells (mild reaction), 2; 25 to 125 cells, (moderate reaction), and 3; 125 or more cells (severe reaction). Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney tests.

RESULTS

There were statistically significant differences in the median inflammatory cell numbers throughout the three test periods, with the most severe degree of inflammation observed at the one-week period. Few cases of necrosis were observed with WMTA. Diaket exhibited the most severe degree of inflammation and necrosis. After 30 days, both materials provoked moderate inflammatory reaction. The eight-week period showed the least severe degree of inflammation in all groups.

CONCLUSIONS

It was concluded that WMTA exhibits a more favourable tissue response compared with Diaket which induced more severe inflammatory reaction than WMTA and the control.

BQ-153, a novel endothelin (ET)A antagonist, attenuates the renal vascular effects of endothelin-1

Endothelin (ET)-l, leukotriene D4 and the thromboxane analogue, U-44069, were all shown to produce dose-dependent reductions in renal blood flow after direct injection into the renal artery of anaesthetized pigs. The effects of ET-1 differed from the other two mediators in that ET-1 caused a transient vasodilator followed by a prolonged vasoconstrictor response. The pressor response was not mediated by the secondary release of either leukotriene D4 or thromboxane A2 as evidenced by the lack of effect of appropriate receptor antagonist MK571 (3-{-2(7-chloro-2 quinolinyl) ethenyl}phenyl{3-(dimethylamino-3-oxopropyl)thio}methyl thio propionic acid) and L-670,596 respectively. This response, however, could be inhibited in a dose-dependent fashion by the selective ETA antagonist, BQ-153 (cyclo-d-sulphalanine-l-Pro-d-Val-l-Leu-d-Trp-). Following blockade by BQ-153 the vasodilator response was unaffected and a residual pressor response remained, suggesting that either or both of these effects were mediated either through an ETB or a novel, as yet undefined, endothelin receptor.

6-Mercaptopurine reverses experimental vasospasm and alleviates the production of endothelins in NO-independent mechanism-a laboratory study

INTRODUCTION

Increased endothelin-1 (ET-1) production and diminished nitric oxide synthase (NOS) bioavailability has been observed in aneurysmal subarachnoid hemorrhage (SAH). The authors previously found that 6-mercaptopurine (6-mp) is effective in preventing and reversing arterial narrowing in a rodent SAH model. This present study is of interest to examine the effect of 6-mp on ET-1/endothelial nitric oxide synthase (eNOS) in this animal model.

METHODS

A rodent double hemorrhage SAH model was employed. Animals were randomly assigned to six groups (sham, SAH only, vehicle, 0.5, 1.0 and 2 mg kg(-1) day(-1) 6-mp treatment). Monoclonal CD45 immunostaining was utilized to evaluate monocytes and microglia. The level of pro-inflammatory cytokines, such as IL-1, IL-6 and TNF-α(RT-PCR), and ET-1 (ELISA) was measured. The basilar arteries (BAs) were harvested and sliced, and their cross-sectional areas were determined. Radiolabeled NOS assay kit was applied to detect eNOS.

RESULTS

Morphologically, convolution of internal elastic lamina, endothelial cells distortion, and necrotic smooth muscle were prevalently present in the basilar artery of SAH groups, which was absent in the 1 and 2 mg kg(-1) day(-1) 6-mp plus SAH group or the healthy controls. Significant vasospasm was noted in the vehicle group (lumen patency, 54.6%, p ≤ 0.01 compared with the sham group), but it was less prominent in the 2 mg kg(-1) day(-1) 6-mp treatment group (lumen patency, 87.6%, p < 0.05). In addition, administration with 2 mg kg(-1) day(-1) 6-mp reduced cytokine levels by 11%, 47%, and 34% for IL-1, IL-6, and TNF-α, respectively, and increased ET-1 levels were found in all the animals subject to SAH (SAH only, SAH plus vehicle, SAH plus 0.5 and 1.0 mg kg(-1) day(-1) 6-mp) except in the 2 mg kg(-1) day(-1) 6-mp SAH group, when compared with the healthy controls (no SAH). Meanwhile, treatment with 6-mp did not induce the levels of expressed eNOS in BAs in the 6-mp groups (0.5, 1.0, and 2 mg kg(-1) day(-1) 6-mp plus SAH) when compared with that in the SAH groups (p > 0.1).

CONCLUSION

In summary, treatment with 6-mp decreased the release of pro-inflammatory cytokines and diminished experimental vasospasm. This study offered first evidence that 6-mp dose-dependently reduces the level of ET-1 in a NO-independent mechanism, which corresponds to its antivasospastic effect in the condition of chronic vasospasm.

Qindan-capsule inhibits proliferation of adventitial fibroblasts and collagen synthesis

AIMS

Qindan-capsule (QC) is a prescription of traditional Chinese medicine for the treatment of hypertension. We investigated the effect and mechanism of QC-containing serum on proliferation of aortal adventitial fibroblasts (AFs) and composition of extracellular matrix (ECM). We also tested whether the Smad3 signaling pathway is activated in the progress.

MATERIALS AND METHODS

AFs were cultured by tissue explant in vitro. The proliferation of AFs induced by transforming growth factor beta1 (TGF-beta1) and affected by QC-containing serum with high or low dose was detected by MTT. The protein and mRNA expressions of Smad3 and Procollagen I were observed by Western blot and Real-time PCR respectively.

RESULTS

Western blot and Real-time PCR revealed that after being activated by TGF-beta1 for 24h, the expressions of Smad3, Pho-Smad3 and Procollagen I were all higher than those in the control group. But these functions were inhibited, to some extent in different doses, by QC-containing serum. So that the proliferation of AFs which was evaluated by MTT.

CONCLUSIONS

The results suggested QC-containing serum has significantly improved proliferation of AFs and composition of extracellular matrix. TGF-beta1/Smad3 signaling pathway may be involved in the mechanism.

Mineral trioxide aggregate-based sealer: analysis of tissue reactions to a new endodontic material

INTRODUCTION

The aim of this study was to evaluate the subcutaneous connective tissue reaction to mineral trioxide aggregate (MTA)-based sealer (Endo CPM Sealer; CPM Sealer; EGEO SRL, Buenos Aires, Argentina), MTA, and an epoxy resin-based sealer (AH Plus; Dentsply HERO Indústria e Comércio Ltda, Petrópolis, RJ, Brazil).

METHODS

Polyethylene tubes containing the test materials and empty tubes (control group) were implanted in the subcutaneous tissue of 18 rats. After 7, 30, and 60 days, observations were made for cellular inflammatory components, fibrous condensation, and abscess formation. Comparisons between groups and periods of time were made using the Friedman test and the Kruskall-Wallis test.

RESULTS

Lymphocytes and plasmacytes were more intensely observed in the reaction to AH Plus sealer after 30 days (p < 0.05). MTA and the Endo CPM Sealer presented a behavior similar to that of the control group throughout the whole experiment.

CONCLUSION

The Endo CPM Sealer presented biological potential. Characteristics of the inflammatory reaction were equivalent to those produced by MTA.

[Effect of spironolactone on L-arginine/iNOS/NO pathway of aortic adventitia in spontaneously hypertensive rats]

OBJECTIVE

Adventitia plays an important role in vascular injury diseases. Nitric oxide (NO) from inducible nitric oxide synthase (iNOS) is involved in many cardiovascular diseases. iNOS/NO pathway is activated in aorta of spontaneously hypertensive rats (SHRs). The role of aldosterone in L-arginine (L-Arg)/iNOS/NO pathway of aortic adventitia is uncertain. We investigated the effect of aldosterone antagonist spironolactone on adventitial L-Arg/iNOS/NO pathway in SHRs.

METHODS

Twenty male SHR (10 weeks old, 220-280 g) were randomly divided into 2 groups (10 in each): untreated or treated with the aldosterone receptor antagonist, spironolactone (20 mg/kg per day) for 6 weeks. Age-matched Wistar-Kyoto rats (WKY) were used as control. Systolic blood pressure (tail-cuff method) was measured weekly. Six weeks later, the rats were sacrificed. The whole aorta was collected and aortic adventitia was isolated. iNOS activity, [(3)H]-L-Arg transport assay of aortic adventitia were carried out by isotope-labeled L-arginine conversion rate measurement, and measurement of nitrate/nitrite (NOx), an index of NO production of aortic adventitia was assayed with the Griess reaction.

RESULTS

iNOS activity, [(3)H]-L-Arg transport and NO production were greatly increased in aortic adventitia of SHR [(12.55 +/- 2.27) pmol x mg(-1) x min(-1), (0.88 +/- 0.19) pmol x mg(-1) x min(-1) and (2.07 +/- 0.39) micromol/L)] compare versus WKY [(5.96 +/- 1.87) pmol x mg(-1) x min(-1), (0.51 +/- 0.15) pmolxmg(-1) x min(-1) and (1.55 +/- 0.32) micromol/L, P < 0.01], and decreased significantly by spironolactone treatment [(8.32 +/- 1.84) pmol x mg(-1) x min(-1), (0.61 +/- 0.15) pmol x mg(-1) x min(-1) and (1.64 +/- 0.27) micromol/L, P < 0.01].

CONCLUSION

L-Arg/iNOS/NO is activated in aortic adventitia of SHR. Spironolactone can inhibit the activation of L-Arg/iNOS/NO pathway. Aldosterone may play an important role in some cardiovascular diseases such as atherosclerosis through iNOS/NO pathway.

Histopathologic study of rat connective tissue responses to maxillofacial silicone elastomers

The aim of this histopathologic study was to assess and compare the subcutaneous connective tissue reaction to three different maxillofacial silicone elastomers (Cosmesil, Multisil, Episil). The test materials were directly inserted subcutaneously into the dorsal subcutaneous tissue of Wistar albino rats. Histopathological examinations were done at 7, 30, and 90 days after the implantation procedure. The presence of inflammation, presence of inflammatory giant cells, and the thickness of fibrous connective tissue adjacent to each inserted sample were recorded. Data was evaluated by analysis of variance, Wilcoxon signed ranks test and Kruskal Wallis test. Cosmesil, Multisil and Episil silicone elastomers at 7 days elicited a severe inflammatory reaction. However, these reactions decreased by the 30 and 90 days. All silicone elastomers elicited a moderate inflammatory reaction at 30 and 90 days. There were no significant differences in tissue reaction between the materials at 7, 30, and 90 days (P > 0.05). All the maxillofacial silicone elastomers evaluated can not be assigned a favorable biocompatibility level based on this study's histologic findings.

Effect of the dental adhesive, 4-META/MMA-TBB resin, on adhesion and keratinization of regenerating oral epithelium

BACKGROUND AND OBJECTIVE

The 4-META/MMA-TBB [4-(2-methacryloxyethyl)trimellitic anhydride/methyl methacrylate-tributylborane] resin is widely used as a dental adhesive. It has also been applied in the dressing of gingival wound surfaces following periodontal surgery. However, its effect on the regeneration and/or cell attachment of the oral epithelium remains to be clarified. To evaluate the effect of the resin applied as a wound dressing, we investigated expression of laminin 5, integrin beta(4) and cytokeratin 14 in regenerating oral epithelium treated with this resin following gingivectomy from the viewpoint of cell attachment and differentiation.

MATERIAL AND METHODS

The resin was applied to the entire wound surface in rats after gingival surgery, and regenerating epithelium was examined immediately and at 1, 3, 5, 7 and 14 days later. The resin was removed 2 weeks after application in some animals and tissue further examined at 1, 3, 5 and 7 days later.

RESULTS

Regenerating epithelium under the resin was not keratinized, but became keratinized immediately after removal of the resin. Laminin 5 and integrin beta(4) were immunolocalized in the basal lamina, the internal basal lamina, in marginal cells of the regenerating epithelium and at the resin-regenerating epithelium interface. Cytokeratin 14 localized in the regenerating epithelium underneath the resin, as well as in healthy and regenerated junctional epithelial cells.

CONCLUSION

These results suggest that this resin covers the wound surface and that the regenerating epithelium biologically adheres to the resin during the initial process of its regeneration.

Fibrillar collagen type I stimulation of apolipoprotein B secretion in Caco-2 cells is mediated by beta1 integrin

Caco-2 cells spontaneously differentiate into enterocyte-like cells and secrete apolipoprotein B (apoB) lipoproteins. We evaluated the effect of different extracellular matrix proteins on lipoprotein secretion by these cells. Caco-2 cells grown on human amnion connective tissue (HACT) secreted twice as much apoB as control cells on Transwells, but secreted similar amounts of apoA1. Cells cultured on fibrillar collagen type I secreted increased amounts of apoB similar to the cells cultured on HACT, but cells cultured on non-fibrillar collagen type I, type IV collagen or laminin-1 did not. The increased secretion was nullified by a function inhibiting anti-integrin beta1 monoclonal antibody. Therefore, interactions between type I collagen and beta1 integrins augment apoB secretion by Caco-2 cells. Cells on HACT formed a more uniform columnar epithelium with lipid droplets polarized to the basolateral membrane. We also studied the effect of extracellular matrix proteins on transepithelial resistance (TER) of differentiated Caco-2 cells. TER in cells cultured on HACT was similar to that on Transwells, but cells on laminin-1 and collagen IV exhibited higher TER. Thus, various extracellular matrix proteins regulate apoB secretion and TER differently. This new observation that extracellular matrix proteins can enhance apoB secretion in Caco-2 cells could be useful to explore the modulation of lipid transport by these proteins.