Implantation of silicon dioxide-based nanocrystalline hydroxyapatite and pure phase beta-tricalciumphosphate bone substitute granules in caprine muscle tissue does not induce new bone formation

Background

Osteoinductive bone substitutes are defined by their ability to induce new bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different bone substitute materials in caprine muscle tissue.

Materials and methods

One gram each of either a porous beta-tricalcium phosphate (β-TCP) or an hydroxyapatite/silicon dioxide (HA/SiO₂)-based nanocrystalline bone substitute material was implanted in several muscle pouches of goats. The biomaterials were explanted at 29, 91 and 181 days after implantation. Conventional histology and special histochemical stains were performed to detect osteoblast precursor cells as well as mineralized and unmineralized bone matrix.

Results

Both materials underwent cellular degradation in which tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cells and TRAP-negative multinucleated giant cells were involved. The ß-TCP was completely resorbed within the observation period, whereas some granules of the HA-groups were still detectable after 180 days. Neither osteoblasts, osteoblast precursor cells nor extracellular bone matrix were found within the implantation bed of any of the analyzed biomaterials at any of the observed time points.

Conclusions

This study showed that ß-TCP underwent a faster degradation than the HA-based material. The lack of osteoinductivity for both materials might be due to their granular shape, as osteoinductivity in goat muscle has been mainly attributed to cylindrical or disc-shaped bone substitute materials. This hypothesis however requires further investigation to systematically analyze various materials with comparable characteristics in the same experimental setting.     

Impact of a prior medical degree on students' dental school performance in Innsbruck, Austria

The purpose of this study was to identify the performance differences between two groups of Austrian dental students (one with a prior medical degree and one without a medical degree) during their dental school training and final dental licensure examination. A specific aim was to determine if having a medical degree is a predictive factor for dental students' scores on the Austrian Dental Admission Test (Austrian DAT), performance in the dental clinic, and scores on final exam. The study consisted of a retrospective analysis of 122 students (thirty-nine with a medical degree and eighty-three without a medical degree) who were enrolled in the Dental Clinic at Innsbruck Medical University, Innsbruck, Austria, between 2001 and 2006. Three performance categories were considered: Austrian DAT results, clinical performance after the first clinical year in dental school, and performance on the final dental licensure examination. Information on students' age, gender, and previous medical degree was collected from official records. Analyses with student's t-test and Pearson's chi-square test revealed that the students with a medical degree had significantly higher Austrian DAT total test scores, grade point averages after the first clinical year, and scores on the final exam. Additionally, those students had significantly better performance on the final exam in prosthodontics and oral and maxillofacial surgery. The linear regression analysis showed that a medical degree had an independent effect on average scores on the final exam, age, and Austrian DAT test scores, while gender showed no statistically significant effect. Overall, the study found that dental students with a prior medical degree had significantly higher Austrian DAT total test scores and performed significantly better in the first clinical year and on the final exam than those without a prior medical degree.     

Direct binding of GABAA receptor β2 and β3 subunits to gephyrin

GABAergic transmission is essential to brain function, and a large repertoire of GABA type A receptor (GABA_AR) subunits is at a neuron's disposition to serve this function. The glycine receptor (GlyR)‐associated protein gephyrin has been shown to be essential for the clustering of a subset of GABA_AR. Despite recent progress in the field of gephyrin‐dependent mechanisms of postsynaptic GABA_AR stabilisation, the role of gephyrin in synaptic GABA_AR localisation has remained a complex matter with many open questions. Here, we analysed comparatively the interaction of purified rat gephyrin and mouse brain gephyrin with the large cytoplasmic loops of GABA_AR α1, α2, β2 and β3 subunits. Binding affinities were determined using surface plasmon resonance spectroscopy, and showed an ~ 20‐fold lower affinity of the β2 loop to gephyrin as compared to the GlyR β loop–gephyrin interaction. We also probed in vivo binding in primary cortical neurons by the well‐established use of chimaeras of GlyR α1 that harbour respective gephyrin‐binding motifs derived from the different GABA_AR subunits. These studies identify a novel gephyrin‐binding motif in GABA_AR β2 and β3 large cytoplasmic loops.     

Comprehensive PKD1 and PKD2 Mutation Analysis in Prenatal Autosomal Dominant Polycystic Kidney Disease

Prenatal forms of autosomal dominant polycystic kidney disease (ADPKD) are rare but can be recurrent in some families, suggesting a common genetic modifying background. Few patients have been reported carrying, in addition to the familial mutation, variation(s) in polycystic kidney disease 1 (PKD1) or HNF1 homeobox B (HNF1B), inherited from the unaffected parent, or biallelic polycystic kidney and hepatic disease 1 (PKHD1) mutations. To assess the frequency of additional variations in PKD1, PKD2, HNF1B, and PKHD1 associated with the familial PKD mutation in early ADPKD, these four genes were screened in 42 patients with early ADPKD in 41 families. Two patients were associated with de novo PKD1 mutations. Forty patients occurred in 39 families with known ADPKD and were associated with PKD1 mutation in 36 families and with PKD2 mutation in two families (no mutation identified in one family). Additional PKD variation(s) (inherited from the unaffected parent when tested) were identified in 15 of 42 patients (37.2%), whereas these variations were observed in 25 of 174 (14.4%, P=0.001) patients with adult ADPKD. No HNF1B variations or PKHD1 biallelic mutations were identified. These results suggest that, at least in some patients, the severity of the cystic disease is inversely correlated with the level of polycystin 1 function.     

Tie – an Accessory Fashion Detail or a Symbol?

Aim

The first aim of this study was to establish the frequency of wearing a tie or business neckerchief on different occasions and in relation to age and educational level. The second aim was to establish whether men who frequently wear a tie were attributed certain characteristics more often than men who rarely wear a tie and to establish whether there were differences in the attribution of these characteristics according to sex, age, educational level, and the frequency of wearing a tie.

Method

Data were collected in 2005 by a method of face to face interview on a national representative sample (n = 1007). Participants estimated how often they wore a tie or business neckerchief on 9 different occasions. They also estimated whether each of 14 characteristics was more pronounced in men who frequently wear a tie.

Results

Tie was most frequently worn on festive and formal occasions, such as weddings and festive gatherings, and least frequently on family gatherings and when traveling. On all occasions, tie was more often worn by men of higher educational level and of older and middle age. A relatively small proportion of Croatian citizens based their conclusions on men’s characteristics on the frequency of wearing a tie. Men who frequently wear a tie were relatively most often attributed the characteristics of ambition, politeness, and respectability, with significant differences found between persons who attributed these characteristics according to sex, age, educational level, and the frequency of wearing a tie by the participants themselves.

Conclusion

Wearing a tie or neckerchief is an exception rather than a rule for most of the Croatian population, and is associated only with specific, primarily festive and formal occasions. Such use of the tie suggests that people adapt their style of clothing to the expectations of others and use it as a specific symbol of the occasion.Clothing is a form of non-verbal communication and represents a systematic way of conscious or unconscious information transmission (1). What distinguishes clothing from other forms of non-verbal communication is that it is the first thing we notice when we meet a person for the first time. Clothing can influence our first impression of a person, create stereotypes, and influence our behavior toward that person (2,3). Therefore, we use clothing as a channel of non-verbal communication for self-presentation and impression management (4). Clothing is also important for our self-concept, since it allows us to feel safer, more assertive, more powerful, and more comfortable in a given situation (4,5). Besides that, the clothes we wear are an example of normative social influence (6), ie the influence we conform to in order to be accepted by a desired social group.More systematic investigation on the influence of clothes on interpersonal relations began in the 1970s and by now a large number of studies have confirmed that people form the impressions on other people on the basis of their physical appearance, especially clothes (7). For example, Damhorst (8), in his review, concluded that 94% of the analyzed experimental studies showed an influence of clothes on the impression formation. Research showed that the way a person is dressed influences the conclusions other people make on their traits and characteristics, such as reliability, competence, power/status, or their workplace (9-13). People not only base their conclusions on clothes itself but also on the appropriateness of clothes to the occasion (7). Different roles or social positions and different occupations or work places are often related to different social norms, including the clothing norm (4,14-16). Even when we do not place much importance on social roles, we still use clothing to adapt to the situation because we care about the reactions of others. Also, appropriate clothing facilitates social interaction and helps us feel more comfortable (4,5). People use clothes to demonstrate similarities in values and beliefs with members of their own group, as well as differences from the groups they do not belong to (17-19). The choice of clothes can show our disagreement with certain norms or terminate unwanted social interactions.The greatest part of the research on the influence of clothes on impression formation and management was conducted in business situations and is related to conventional or classic clothing style (14-16,20). These studies have shown that the applicant’s clothing at interview has an influence on whether he or she will get a job, and that classically or conventionally dressed people are more positively evaluated. Classic or conventional clothing includes a suit for both men and women and a tie for men. It has been proven that this style of clothing is associated with competence and authority in both men and women, not only in business situations (15,21-25).According to the available data, 600-700 million people across the world wear a tie every day, and more than two billion Euro is spent on ties every year, which is more than a yearly budget of some smaller states (26). According to Johnson (27), the earliest known version of the tie was found in the mausoleum of the first emperor of China, Shih Huang Ti, who was buried in 210 BC. Tie’s modern history began in the 17th century, when Croatian soldiers fighting in the Thirty Years'' War spread its forerunner, known as the cravat, all over Europe. In his monograph Le grande histoire de la cravate, Francois Chaille confirms and discusses the Croatian origin of the cravat (Figure 1), while the Encyclopćdia Britannica states that the noun “cravat” originated from the words Crabata, Cravata, and Croatian, mentioning the year 1656 as the year of its appearance (26). The French readily accepted the special way of tying a piece of cloth around the neck “a la Croate” and citizens of Paris soon took it to be a symbol of progress (26). During the French revolution, black cravats were worn as a sign of protest against reactionary ideas, and the cravat soon became a symbol of culture and elegance (26). While the French saw the cravat as a decoration and a symbol of progress, for the Croatian it was primarily a symbol of fidelity. According to the popular tradition, wives and girlfriends would give cravats to soldiers as a token of their love, to give them courage and comfort in difficulties and danger. On the other hand, by wearing a cravat, the soldier would show the respect for his beloved. This custom symbolized a man''s loyalty to a woman, as well as established loyalty as a virtue (28). Therefore, through the history, the tie has symbolized loyalty, culture, refinement, style, and elegance; according to Johnson (27) the tie has symbolized social status, occupation/work place, identity, as well as group belonging.Open in a separate windowFigure 1Tie with a traditional Croatian pattern called pleter.In order to examine contemporary symbolical connotations of the tie, we analyzed the frequency of wearing a tie on various occasions among the citizens of Croatia of different age and educational level, as well as the characteristics attributed to men who frequently wear a tie. Since tie is a garment worn usually by men, we analyzed the frequency of wearing a business neckerchief among women.Specific aims of the study were: 1) to establish the frequency of wearing a tie orbusiness neckerchief on different occasions among people of different age and educational levels; 2) to establish whether men who frequently wear a tie were attributed certain characteristics more often than men who wear a tie rarely and to establish whether there were differences in the attribution of these characteristics according to age and educational levels; and 3) to establish whether there are differences between men in the attribution of characteristics to other men who frequently wear a tie with regard to the number of different situations in which men themselves frequently wear a tie.     

Detection of hyphal fusion in filamentous fungi using differently fluorescence-labeled histones

Cell fusion occurs regularly during the vegetative and sexual phases of the life cycle in filamentous fungi. Here, we present a simple and efficient method that can detect even rare hyphal fusion events. Using the homothallic ascomycete Sordaria macrospora as an experimental system, we developed a histone-assisted merged fluorescence (HAMF) assay for the investigation of hyphal fusion between vegetative mycelia. For this purpose, two reporter vectors were constructed encoding the histone proteins HH2B or HH2A fused at their C terminus either with the cyan or yellow fluorescent protein, respectively. The chimeric proteins generate fluorescently labeled nuclei and thus enable the distinction between different strains in a mycelial mixture. For example, hyphae with nuclei that show both cyan as well as yellow fluorescence indicate the formation of a heterokaryon as a result of hyphal fusion. To test the applicability of our HAMF assay, we used two S. macrospora developmental mutants that are supposed to have reduced hyphal fusion rates. The simple and efficient HAMF assay described here could detect even rare fusion events and should be applicable to a broad range of diverse fungal species including those lacking male or female reproductive structures or asexual spores. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Christine Rech and Ines Engh contributed equally to this work.