Distribution of biglycan and decorin in rat dental tissue

Biglycan and decorin are small leucine-rich proteoglycans that play several biological and structural roles in different tissues and organs. Several reports have indicated that biglycan participates in odontoblast and ameloblast differentiation and in the calcification process. In the present study we show that the expression of biglycan changes from within the ameloblasts and odontoblasts to the extracellular space according to the stage of animal development. In predentin and in the pulp space, however, biglycan was continually expressed throughout the period of investigation. In contrast, decorin was absent in odontoblasts and in ameloblasts and was exclusively expressed in predentin throughout the period of observation. In young rats, however, decorin was expressed in the extracellular spaces of the pulp, where it was concentrated mainly in the peripheral pulp.

Dental fear in adolescents' transition to early adulthood

The aims of the study were to assess the validity of a clinical dental fear question (Short Dental Fear Question, SDFQ) and an instrument measuring interaction between adolescents and dental staff (Patient Dental Staff Interaction Questionnaire, PDSIQ). Also, adolescents’ subjective perception of interaction with dental staff, the association with adolescents’ dental fear and sense of coherence as well as a multi-professional small-group intervention model for decreasing high dental fear were assessed. The study sample comprised Finnish adolescents in transition to early adulthood, aged 18–26 years (n = 777, n = 773, n = 5), except for a sample of 15-year-old adolescents (n = 27). Dental fear, sense of coherence (SOC) and the adolescents’ perceived interaction with dental staff were assessed with questionnaires. The principles of fear treatment such as gradual exposure, relaxation, encouragement and cornerstones of the reteaming method based on a solution-focused framework to maintain motivation and peer support were used to decrease fear in the intervention study. The SDFQ was found to be a valid dental fear instrument and the PDSIQ a valid interaction instrument with five factors of interaction retrieved: ‘kind atmosphere and mutual communication’, ‘roughness’, ‘insecurity’, ‘trust and safety’, and ‘shame and guilt’. Highly fearful young adults more often perceived their interaction with dental staff as negative, more often felt insecure and had a weaker sense of coherence compared to their peers with no to moderate dental fear. The results of the intervention study showed that young adults’ high dental fear decreased and their commitment to dental treatment increased. The SDFQ is clinically feasible and informative instrument in measuring dental fear. Knowledge of the level of fear enables dental staff to better consider an adolescent’s fear. Dental staff should be aware that a supportive interaction style, creating trust and safety, is especially beneficial for highly dentally fearful young adults. A weak SOC may affect young adults’ high dental fear in that they would not have enough tools to manage their fear. A multi-professional small therapeutic group seems to increase fearful young adults’ resources for confronting dental treatment.

Effect of one stretch a week applied to the immobilized soleus muscle on rat muscle fiber morphology

We determined the effect of stretching applied once a week to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Twenty-six male Wistar rats weighing 269 ± 26 g were divided into three groups. Group I, the left soleus was immobilized in the shortened position for 3 weeks; group II, the soleus was immobilized in the shortened position and stretched once a week for 3 weeks; group III, the soleus was submitted only to stretching once a week for 3 weeks. The medial part of the soleus muscle was frozen for histology and muscle fiber area evaluation and the lateral part was used for the determination of number and length of serial sarcomeres. Soleus muscle submitted only to immobilization showed a reduction in weight (44 ± 6%, P = 0.002), in serial sarcomere number (23 ± 15%) and in cross-sectional area of the fibers (37 ± 31%, P < 0.001) compared to the contralateral muscles. The muscle that was immobilized and stretched showed less muscle fiber atrophy than the muscles only immobilized (P < 0.05). Surprisingly, in the muscles submitted only to stretching, fiber area was decreased compared to the contralateral muscle (2548 ± 659 vs 2961 ± 806 µm², respectively, P < 0.05). In conclusion, stretching applied once a week for 40 min to the soleus muscle immobilized in the shortened position was not sufficient to prevent the reduction of muscle weight and of serial sarcomere number, but provided significant protection against muscle fiber atrophy. In contrast, stretching normal muscles once a week caused a reduction in muscle fiber area.

Effect of passive stretching on the immobilized soleus muscle fiber morphology

The aim of the present study was to determine the effect of stretching applied every 3 days to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Eighteen 16-week-old Wistar rats were used and divided into three groups of 6 animals each: a) the left soleus muscle was immobilized in the shortened position for 3 weeks; b) during immobilization, the soleus was stretched for 40 min every 3 days; c) the non-immobilized soleus was only stretched. Left and right soleus muscles were examined. One portion of the soleus was frozen for histology and muscle fiber area evaluation, while the other portion was used to identify the number and length of serial sarcomeres. Immobilized muscles (group A) showed a significant decrease in weight (44 ± 6%), length (19 ± 7%), serial sarcomere number (23 ± 15%), and fiber area (37 ± 31%) compared to the contralateral muscles (P < 0.05, paired Student t-test). The immobilized and stretched soleus (group B) showed a similar reduction but milder muscle fiber atrophy compared to the only immobilized group (22 ± 40 vs 37 ± 31%, respectively; P < 0.001, ANOVA test). Muscles submitted only to stretching (group C) significantly increased the length (5 ± 2%), serial sarcomere number (4 ± 4%), and fiber area (16 ± 44%) compared to the contralateral muscles (P < 0.05, paired Student t-test). In conclusion, stretching applied every 3 days to immobilized muscles did not prevent the muscle shortening, but reduced muscle atrophy. Stretching sessions induced hypertrophic effects in the control muscles. These results support the use of muscle stretching in sports and rehabilitation.

Skin morphology of the mutant hairless USP mouse

The morphology of the skin of the mutant hairless USP mouse was studied by histological, histochemical and immunohistochemical methods and compared to the skin of BALB/c mice. Representative sections of the dorsal skin from mice of both strains aged 18 days, and 1, 3, 6, and 8 months were studied. Sections stained with hematoxylin and eosin showed cystic formations called utricles and dermal cysts in the dermis that increased in size and number during growth. Skin thickness increased significantly at 8 months. Sections stained with picrosirius and examined with polarized light, displayed different colors, suggesting different thicknesses of dermal collagen fibers (probably types I and III). Weigert, Verhoeff and resorcin-fuchsin stains revealed fibers of the elastic system. The PAS and Alcian blue methods revealed neutral and acid glycosaminoglycans in the skin ground substance of both mouse strains. Immunohistochemical staining for fibronectin and laminin did not show differences between the mutant and BALB/c mice. Mast cells stained by the Gomori method and macrophages positive for HAM 56 antibodies were observed in both mouse strains. Except for the presence of enlarged cysts in the hairless strain, no qualitative differences were found during development of the skin of BALB/c and the mutant hairless mice.

Effect of unsaturated fatty acids on myocardial performance, metabolism and morphology

Diets rich in saturated fatty acids are one of the most important causes of atherosclerosis in men, and have been replaced with diets rich in unsaturated fatty acids (UFA) for the prevention of this disorder. However, the effect of UFA on myocardial performance, metabolism and morphology has not been completely characterized. The objective of the present investigation was to evaluate the effects of a UFA-rich diet on cardiac muscle function, oxidative stress, and morphology. Sixty-day-old male Wistar rats were fed a control (N = 8) or a UFA-rich diet (N = 8) for 60 days. Myocardial performance was studied in isolated papillary muscle by isometric and isotonic contractions under basal conditions after calcium chloride (5.2 mM) and ß-adrenergic stimulation with 1.0 µM isoproterenol. Fragments of the left ventricle free wall were used to study oxidative stress and were analyzed by light microscopy, and the myocardial ultrastructure was examined in left ventricle papillary muscle. After 60 days the UFA-rich diet did not change myocardial function. However, it caused high lipid hydroperoxide (176 ± 5 vs 158 ± 5, P < 0.0005) and low catalase (7 ± 1 vs 9 ± 1, P < 0.005) and superoxide-dismutase (18 ± 2 vs 27 ± 5, P < 0.005) levels, and discrete morphological changes in UFA-rich diet hearts such as lipid deposits and mitochondrial membrane alterations compared to control rats. These data show that a UFA-rich diet caused myocardial oxidative stress and mild structural alterations, but did not change mechanical function.

Association between dental-oral health in young adults and salivary glutathione, lipid peroxidation and sialic acid levels and carbonic anhydrase activity

The aim of the present study was to evaluate the relationship between salivary oxidative stress and dental-oral health. Healthy young adults, matched for gender and age, with (N = 21, 10 men, mean age: 20.3 ± 1 years) and without (N = 16, 8 men, mean age: 21.2 ± 1.8 years) caries were included in this study. The World Health Organization (WHO) caries diagnostic criteria were used for determining the decayed, missing, filled teeth (DMFT) index. The oral hygiene and gingival status were assessed using the simplified oral hygiene index and gingival index, respectively. Unstimulated salivary total protein, glutathione (GSH), lipid peroxidation and total sialic acid levels, carbonic anhydrase activity, and salivary buffering capacity were determined by standard methods. Furthermore, salivary pH was measured with pH paper and salivary flow rate was calculated. Simplified oral hygiene index and gingival index were not significantly different between groups but DMFT scores were significant (P < 0.01). Only, GSH values were significantly different (P < 0.05) between groups (2.2 and 1.6 mg/g protein in young adults without caries and with caries, respectively). There was a significant negative correlation between DMFT and GSH (r = -0.391; P < 0.05; Pearson's correlation coefficient). Our results suggest that there is an association between caries history and salivary GSH levels.

Lipopolysaccharide-induced dental pulp cell apoptosis and the expression of Bax and Bcl-2 in vitro

Lipopolysaccharide exerts many effects on many cell lines, including cytokine secretion, and cell apoptosis and necrosis. We investigated the in vitro effects of lipopolysaccharide on apoptosis of cultured human dental pulp cells and the expression of Bcl-2 and Bax. Dental pulp cells showed morphologies typical of apoptosis after exposure to lipopolysaccharide. Flow cytometry showed that the rate of apoptosis of human dental pulp cells increased with increasing lipopolysaccharide concentration. Compared with controls, lipopolysaccharide promoted pulp cell apoptosis (P < 0.05) from 0.1 to 100 μg/mL but not at 0.01 μg/mL. Cell apoptosis was statistically higher after exposure to lipopolysaccharide for 3 days compared with 1 day, but no difference was observed between 3 and 5 days. Immunohistochemistry showed that expression of Bax and Bcl-2 was enhanced by lipopolysaccharide at high concentrations, but no evident expression was observed at low concentrations (0.01 and 0.1 μg/mL) or in the control groups. In conclusion, lipopolysaccharide induced dental pulp cell apoptosis in a dose-dependent manner, but apoptosis did not increase with treatment duration. The expression of the apoptosis regulatory proteins Bax and Bcl-2 was also up-regulated in pulp cells after exposure to a high concentration of lipopolysaccharide.

In vitro culture and characterization of alveolar bone osteoblasts isolated from type 2 diabetics

In order to understand the mechanisms of poor osseointegration following dental implants in type 2 diabetics, it is important to study the biological properties of alveolar bone osteoblasts isolated from these patients. We collected alveolar bone chips under aseptic conditions and cultured them in vitro using the tissue explants adherent method. The biological properties of these cells were characterized using the following methods: alkaline phosphatase (ALP) chemical staining for cell viability, Alizarin red staining for osteogenic characteristics, MTT test for cell proliferation, enzyme dynamics for ALP contents, radio-immunoassay for bone gla protein (BGP) concentration, and ELISA for the concentration of type I collagen (COL-I) in the supernatant. Furthermore, we detected the adhesion ability of two types of cells from titanium slices using non-specific immunofluorescence staining and cell count. The two cell forms showed no significant difference in morphology under the same culture conditions. However, the alveolar bone osteoblasts received from type 2 diabetic patients had slower growth, lower cell activity and calcium nodule formation than the normal ones. The concentration of ALP, BGP and COL-I was lower in the supernatant of alveolar bone osteoblasts received from type 2 diabetic patients than in that received from normal subjects (P < 0.05). The alveolar bone osteoblasts obtained from type 2 diabetic patients can be successfully cultured in vitro with the same morphology and biological characteristics as those from normal patients, but with slower growth and lower concentration of specific secretion and lower combining ability with titanium than normal ones.

Effect of different durations of overdistention on rat bladder function and morphology

We investigated the contribution of the duration of overdistention (DOD) to rat bladder function and morphology and explored its possible molecular mechanisms. Bladder overdistention was induced in male Sprague-Dawley rats (200-250 g) by an infusion of saline. Forty rats were divided into 5 groups submitted to different DOD, i.e., 1, 2, 4, and 8 h, and control. Bladder function was evaluated by cystometry. Morphological changes were observed by light and transmission electron microscopy. Compared to control (44.567 ± 3.472 cmH2O), the maximum detrusor pressure of groups with 2-, 4- and 8-h DOD decreased significantly (means ± SEM): 32.774 ± 3.726, 31.321 ± 2.847, and 29.238 ± 3.724 cmH2O. With the increase of DOD, inflammatory infiltration and impairment of ultrastructure were more obvious in bladder tissue. Compared to control (1.90 ± 0.77), the apoptotic indexes of groups with 1-, 2-, 4-, and 8-h DOD increased significantly (6.47 ± 2.10, 10.66 ± 1.97, 13.91 ± 2.69, and 18.33 ± 3.28%). Compared to control (0.147 ± 0.031/0.234 ± 0.038 caspase 3/β-actin and Bax/Bcl-2 ratios), both caspase 3/β-actin and Bax/Bcl-2 ratios of 1-, 2-, 4-, and 8-h DOD increased significantly (0.292 ± 0.037/0.508 ± 0.174, 0.723 ± 0.173/1.745 ± 0.471, 1.104 ± 0.245/4.000 ± 1.048, and 1.345 ± 0.409/8.398 ± 3.332). DOD plays an important role in impairment of vesical function and structure. With DOD, pro-apoptotic factors increase and anti-apoptotic factors decrease, possibly contributing to the functional deterioration and morphological changes of the bladder.

Relationships between dendritic morphology, spatial distribution and firing patterns in rat layer 1 neurons

The cortical layer 1 contains mainly small interneurons, which have traditionally been classified according to their axonal morphology. The dendritic morphology of these cells, however, has received little attention and remains ill defined. Very little is known about how the dendritic morphology and spatial distribution of these cells may relate to functional neuronal properties. We used biocytin labeling and whole cell patch clamp recordings, associated with digital reconstruction and quantitative morphological analysis, to assess correlations between dendritic morphology, spatial distribution and membrane properties of rat layer 1 neurons. A total of 106 cells were recorded, labeled and subjected to morphological analysis. Based on the quantitative patterns of their dendritic arbor, cells were divided into four major morphotypes: horizontal, radial, ascendant, and descendant cells. Descendant cells exhibited a highly distinct spatial distribution in relation to other morphotypes, suggesting that they may have a distinct function in these cortical circuits. A significant difference was also found in the distribution of firing patterns between each morphotype and between the neuronal populations of each sublayer. Passive membrane properties were, however, statistically homogeneous among all subgroups. We speculate that the differences observed in active membrane properties might be related to differences in the synaptic input of specific types of afferent fibers and to differences in the computational roles of each morphotype in layer 1 circuits. Our findings provide new insights into dendritic morphology and neuronal spatial distribution in layer 1 circuits, indicating that variations in these properties may be correlated with distinct physiological functions.

Oculo-facio-cardio-dental syndrome in three succeeding generations: genotypic data and phenotypic features

Oculo-facio-cardio-dental (OFCD) syndrome is a rare X-linked disorder mainly manifesting in females. Patients show ocular, facial, cardiac, and dental abnormalities. OFCD syndrome is caused by heterozygous mutations in the BCOR gene, located in Xp11.4, encoding the BCL6 co-repressor. We report a Croatian family with four female members (grandmother, mother and monozygotic female twins) diagnosed with OFCD syndrome who carry the novel BCOR mutation c.4438C>T (p.R1480*). They present high intrafamilial phenotypic variability with special regard to cardiac defect and cataract that showed more severe disease expression in successive generations. Clinical and radiographic examination of the mother of the twins revealed a talon cusp involving the permanent maxillary right central incisor. This is the first known report of a talon cusp in OFCD syndrome with a novel mutation in the BCOR gene.

Overexpression of myeloid differentiation protein 88 in mice induces mild cardiac dysfunction, but no deficit in heart morphology

Cardiac remodeling involves changes in heart shape, size, structure, and function after injury to the myocardium. The proinflammatory adaptor protein myeloid differentiation protein 88 (MyD88) contributes to cardiac remodeling. To investigate whether excessive MyD88 levels initiate spontaneous cardiac remodeling at the whole-organism level, we generated a transgenic MyD88 mouse model with a cardiac-specific promoter. MyD88 mice (male, 20-30 g, n=∼80) were born at the expected Mendelian ratio and demonstrated similar morphology of the heart and cardiomyocytes with that of wild-type controls. Although heart weight was unaffected, cardiac contractility of MyD88 hearts was mildly reduced, as shown by echocardiographic examination, compared with wild-type controls. Moreover, the cardiac dysfunction phenotype was associated with elevation of ANF and BNP expression. Collectively, our data provide novel evidence of the critical role of balanced MyD88 signaling in maintaining physiological function in the adult heart.

Evaluation of novel programs in health counseling – their effectiveness in the oral health of young children, and their acceptance by parents and professionals in public dental service.

Aim and design: To evaluate family-based health counseling for young children, and to study the significance of adding parental self-care or the training of professionals to the programs. The effectiveness and acceptability of the programs were evaluated by comparing two new programs with an earlier one. Subjects and methods: The study was carried out in Vantaa, which was divided into three study areas. The subjects consisted of children born in 2008, particularly fi rstborn children, while children born in 2006 formed the historical control. The fi rst of the new programs emphasized oral hygiene and use of fl uoride, and the second program focused on proper diet and use of xylitol. The main outcome measure was mutansstreptococci (MS) in the dental biofi lm of two-year-olds, and the opinions of parents and dental professionals were evaluated using questionnaires. Results: The programs found wide acceptance among dental professionals. There were no group-related differences found in the MS scores of the two-year-olds. However, all groups combined, father’s advanced level of education and child’s proper use of xylitol were associated with negative MS scores. In the opinion of parents, the oral healthcare guidance at least somewhat met their expectations. Conclusions: The present fi ndings suggest that providing training and support for professionals in health education is important. The addition of parental self-care to supplement programs aimed at young children does not improve the program, although it may improve parental readiness to change their own health habits. Counseling for families might be best carried out through a routine patient-centered program.

Fiber-reinforced composite fixed dental prostheses: Studies of the materials used as pontics

Fiber-reinforced composite fixed dental prostheses – Studies of the materials used as pontics University of Turku, Faculty of Medicine, Institute of Dentistry, Department of Biomaterials Science, Finnish Doctoral Program in Oral Sciences – FINDOS, Annales Universitatis Turkuensis, Turku, Finland 2015 Fiber-reinforced composites (FRC), a non-metallic biomaterial, represent a suitable alternative in prosthetic dentistry when used as a component of fixed dental prostheses (FDPs). Some drawbacks have been identified in the clinical performance of FRC restorations, such as delamination of the veneering material and fracture of the pontic. Therefore, the current series of studies were performed to investigate the possibilities of enhancing the mechanical and physical properties of FRC FDPs by improving the materials used as pontics, to then heighten their longevity. Four experiments showed the importance of the pontic design and surface treatment in the performance of FRC FDPs. In the first, the load-bearing capacities of inlay-retained FRC FDPs with pontics of various materials and thicknesses were evaluated. Three different pontic materials were assessed with different FRC framework vertical positioning. Thicker pontics showed increased load-bearing capacities, especially ceramic pontics. A second study was completed investigating the influence of the chemical conditioning of the ridge-lap surface of acrylic resin denture teeth on their bonding to a composite resin. Increased shear bond strength demonstrated the positive influence of the pretreatment of the acrylic surfaces, indicating dissolution of the denture surfaces, and suggesting potential penetration of the monomer systems into the surface of denture teeth. A third study analyzed the penetration depth of different monomer systems on the acrylic resin denture teeth surfaces. The possibility of establishing a durable bond between acrylic pontics and FRC frameworks was demonstrated by the ability of monomers to penetrate the surface of acrylic resin denture teeth, measured by a confocal scanning type microscope. A fourth study was designed to evaluate the load-bearing capacities of FRC FDPs using the findings of the previous three studies. In this case, the performance of pre-shaped acrylic resin denture teeth used as pontics with different composite resins as filling materials was evaluated. The filling material influenced the load-bearing capacities, providing more durable FRC FDPs. It can be concluded that the mechanical and physical properties of FRC FDPs can be improved as has been shown in the development of this thesis. The improvements reported then might provide long lasting prosthetic solutions of this kind, positioning them as potentially permanent rehabilitation treatments. Key words: fiber-reinforced composite, fixed dental prostheses, inlay-retained bridges, adhesion, acrylic resin denture teeth, dental material.