The relation between lateralisation,early start of training,and amount of practice in musicians: A contribution to the problem of handedness classification

This study investigates the influence of extensive bimanual training in professional musicians on the incidence of handedness in the most basic form of right-handedness (RH) and non-right-handedness (NRH), according to Annett's “right shift theory”. The lateralisation coefficients (LCs) of a total sample of 128 bimanually performing music students were calculated for speed, regularity, and fatigue of tapping by using the speed tapping paradigm. Additionally, the accumulated amount of practice was recorded by means of retrospective interviews. The proportion of designated right-handers (dRH) and non-right-handers (dNRH) in hand performance was identified by binary logistic regression from LCs. A proportion of 30.8% designated NRH in the group of musicians was found, while in the control group of non-musicians (matched for age range) a proportion of 21.7% designated NRH was observed. Incidence of dNRH was higher in string players (35.6%) than in pianists (27.1%). As an effect of the extensive training of the left hand, tapping regularity increased and tapping fatigue decreased among those participants who evidenced an increased amount of accumulated practice time on the instrument. However, speed difference between hands (as indicated by LCs) remained uninfluenced by bimanual training. This finding is in contrast to those of Jäncke, Schlaug, and Steinmetz (1997). Finally, our study provides a more reliable (statistical) classification as an external criterion for future genetic analyses of handedness.     

Odor Identification and Self-reported Olfactory Functioning in Patients with Subtypes of Mild Cognitive Impairment

Olfactory dysfunction is a very early symptom of Alzheimer's disease (AD), and olfactory dysfunction has also been found in mild cognitive impairment (MCI). The goal of the present study was to compare odor identification ability and self-reported olfactory functioning in patients with different types of MCI. We included 104 elderly participants classified into two groups: patients with mild cognitive impairment (MCI) and elderly controls (EC). Based on their performance in neuropsychological testing the study population was divided into four groups of participants based on cognitive features: amnestic MCI single domain (11), amnestic MCI multiple domain (19), non-amnestic MCI single domain (21) and non-amnestic MCI multiple domain (13), respectively. The MCI patients were compared to 40 elderly controls (EC) controls with no cognitive deficit. Comparison for odor identification revealed a significant difference between amnestic MCI multiple domain patients and the EC group. No other group comparison was significant. Statistical analyses for self-reported olfactory functioning revealed no significant group differences between any subgroup of MCI patients and the control group. Correlational analyses indicated that odor identification ability was related to cognition whereas no relationship was found for self-reported olfactory functioning. The present study showed that amnestic MCI patients with additional deficits in other cognitive domains have a specific odor identification impairment. Together with cognitive testing, olfactory testing may more accurately help predict whether or not a patient with MCI will convert to AD in the near future.     

Multiaxial mechanical response and constitutive modeling of esophageal tissues: Impact on esophageal tissue engineering

Congenital defects of the esophagus are relatively frequent, with 1 out of 2500 babies suffering from such a defect. A new method of treatment by implanting tissue engineered esophagi into newborns is currently being developed and tested using ovine esophagi. For the reconstruction of the biological function of native tissues with engineered esophagi, their cellular structure as well as their mechanical properties must be considered. Since very limited mechanical and structural data for the esophagus are available, the aim of this study was to investigate the multiaxial mechanical behavior of the ovine esophagus and the underlying microstructure. Therefore, uniaxial tensile, biaxial tensile and extension-inflation tests on esophagi were performed. The underlying microstructure was examined in stained histological sections through standard optical microscopy techniques. Moreover, the uniaxial ultimate tensile strength and residual deformations of the tissue were determined. Both the mucosa-submucosa and the muscle layers showed nonlinear and anisotropic mechanical behavior during uniaxial, biaxial and inflation testing. Cyclical inflation of the intact esophageal tube caused marked softening of the passive esophagi in the circumferential direction. The rupture strength of the mucosa-submucosa layer was much higher than that of the muscle layer. Overall, the ovine esophagus showed a heterogeneous and anisotropic behavior with different mechanical properties for the individual layers. The intact and layer-specific multiaxial properties were characterized using a well-known three-dimensional microstructurally based strain-energy function. This novel and complete set of data serves the basis for a better understanding of tissue remodeling in diseased esophagi and can be used to perform computer simulations of surgical interventions or medical-device applications.     

Shear strength after ethylenediaminetetraacetic acid conditioning of dentin

On the basis of previous studies, it was hypothesized that a chelating agent such as ethylenediaminetetraacetic acid (EDTA) in a saturated aqueous solution (24%)can function as a dentin conditioning agent with exposure times comparable to that of phosphoric acid without compromising shear bond strength. Thirty caries-free human third molars, divided equally between two groups, were used. In group one, four experimental surfaces were prepared on each tooth, and cylindrical copper matrixes with a diameter of 5 mm were attached to the prepared surfaces. The experimental surfaces were then treated with a 24% EDTA gel for 30, 60, 120, or 240 sec, respectively. Dentin was bonded with All Bond 2, after which a flowable composite was added and light-cured. In group two, which served as control, two surfaces were prepared on each tooth. One surface was left unetched, whereas the other side was treated with 24% EDTA-gel for 30 sec. A shear bond strength test was performed at a crosshead speed of 1 mm/min until the composite debonded. There was no statistically significant difference (P < 0.89) between results of the shear bond strength test for the different EDTA conditioning times. The control group showed a significant difference in shear bond strength between untreated surfaces and surfaces conditioned for 30 sec with EDTA. Thus, the results indicate that the duration of EDTA gel conditioning of dentin surfaces need not exceed that of phosphoric acid in clinical practice to obtain an acceptable level of bond strength.     

Periodontal Probing of Dental Furcations Compared With Diagnosis by Low‐Dose Computed Tomography: A Case Series

Background: Therapeutic decisions in periodontal surgery are based on the accurate diagnosis of the furcation. Clinical probing is the basic diagnostic tool; however, the accuracy of clinical probing to distinguish Class II and Class III furcation defects is unknown. Therefore, this study compares clinical probing diagnoses to those of computed tomography (CT). Methods: Seventy‐five patients with severe periodontal disease were enrolled in this case series study. A total of 582 furcation sites in molars were assigned for the diagnosis of Class II and Class III furcation defects by clinical probing. Diagnosis based on CT served as a reference. Results: The degree of furcation involvement on clinical findings was confirmed in 57% of the sites, whereas 20% were overestimated and 23% were underestimated compared with the radiologic analysis. Only 32% of Class III furcations in the CT scan were detected clinically. The best correlation of CT scan and clinical probing was found at buccal furcation sites in the mandible, with a κ‐coefficient of 0.52, and buccal furcation sites in the maxilla, κ = 0.38. The κ‐coefficient was 0.35 for lingual furcations, 0.29 for mesial furcations, and 0.27 for distal furcations, showing weaker correlations. Conclusions: CT scans offer more detailed information on furcation involvement than clinical probing. Especially before surgical treatment, three‐dimensional radiographic imaging can be a useful tool to assess the degree of furcation involvement and optimize treatment decisions.     

Porphyromonas gingivalis HmuY‐Induced Production of Interleukin‐6 and IL‐6 Polymorphism in Chronic Periodontitis

Background: In chronic periodontitis (CP), the gene polymorphism of interleukin‐6 (IL‐6) to 174C/G has been associated with the altered production of this cytokine. The aim of this pilot study is to compare the allelic and genotypic frequencies in patients with CP with control individuals without periodontitis (NP) and to measure the production of IL‐6 by whole blood cells stimulated with Porphyromonas gingivalis HmuY protein. Methods: DNA was isolated from peripheral blood cells of 49 patients with CP and 60 control individuals classified as NP, and genotyping was performed by polymerase chain reaction using sequence‐specific primers. Whole blood cells from 29 patients with CP and 30 control individuals were stimulated for 48 hours with HmuY, and IL‐6 levels were measured using enzyme‐linked immunosorbent assay. Results: The proportion of individuals carrying the G allele at position –174 of the IL‐6 gene was higher in the group with CP (85.7%) than in the normal control group (73.3%; P <0.03). P. gingivalis HmuY‐induced production of IL‐6 was higher in the group with CP (P <0.05). Conclusions: Our findings suggest that P. gingivalis HmuY may be associated with increased IL‐6 production during CP. Furthermore, patients with periodontitis and individuals with higher HmuY‐induced production of IL‐6 show a high frequency of the G allele at position –174.