Correlation between symptoms and external characteristics of cracked teeth: Findings from The National Dental Practice-Based Research Network

Background

Cracked teeth are ubiquitous in the adult dentition. The objective of this study was to determine which patient traits and behaviors and external tooth and crack characteristics correlate with cracked teeth being symptomatic.

Isolation and structure determination of two microcystins and sequence comparison of the McyABC adenylation domains in Planktothrix species

Microcystins (MCs) are toxic heptapeptides found in cyanobacteria and share the common structure cyclo(-d-Ala(1)-l-X(2)-d-isoMeAsp(3)-l-Z(4)-Adda(5)-d-isoGlu(6)-Mdha(7)). The letters X and Z in the general formula above represent a wide range of l-amino acids that occupy positions 2 and 4, respectively. In general the variation in structural variants is due to the exchange of amino acids in position 7, 2, and 4. In the present work we report two homotyrosine (Hty)-containing microcystin variants, [d-Asp(3),(E)-Dhb(7)]-MC-HtyY (1) and [d-Asp(3),(E)-Dhb(7)]-MC-HtyHty (2), which were isolated from strain No80 of Planktothrix rubescens. Their structures were elucidated using amino acid analysis as well as 1D and 2D NMR techniques. The adenylation domains of McyABC involved in amino acid activation in positions 7, 2, and 4 of the microcystin molecule, respectively, were compared with corresponding genes of Planktothrix strain CYA126/8 producing [d-Asp(3),Mdha(7)]-MC-RR and [d-Asp(3),Mdha(7)]-MC-LR. While the adenylation domain comparison of McyAB between the two Planktothrix strains revealed considerable DNA recombination, the adenylation domain of McyC showed only a single amino acid substitution, which was correlated with the replacement of Arg by Hty in position 4 of the microcystin molecule.     

Nutritional improvement of the endothelial control of vascular tone by polyphenols: role of NO and EDHF

Numerous studies indicate that regular intake of polyphenol-rich beverages (red wine and tea) and foods (chocolate, fruit, and vegetables) is associated with a protective effect on the cardiovascular system in humans and animals. Beyond the well-known antioxidant properties of polyphenols, several other mechanisms have been shown to contribute to their beneficial cardiovascular effects. Indeed, both experimental and clinical studies indicate that polyphenols improve the ability of endothelial cells to control vascular tone. Experiments with isolated arteries have shown that polyphenols cause nitric oxide (NO)-mediated endothelium-dependent relaxations and increase the endothelial formation of NO. The polyphenol-induced NO formation is due to the redox-sensitive activation of the phosphatidylinositol3-kinase/Akt pathway leading to endothelial NO synthase (eNOS) activation subsequent to its phosphorylation on Ser 1177. Besides the phosphatidylinositol3-kinase/Akt pathway, polyphenols have also been shown to activate eNOS by increasing the intracellular free calcium concentration and by activating estrogen receptors in endothelial cells. In addition to causing a rapid and sustained activation of eNOS by phosphorylation, polyphenols can increase the expression level of eNOS in endothelial cells leading to an increased formation of NO. Moreover, the polyphenol-induced endothelium-dependent relaxation also involves endothelium-derived hyperpolarizing factor, besides NO, in several types of arteries. Altogether, polyphenols have the capacity to improve the endothelial control of vascular tone not only in several experimental models of cardiovascular diseases such as hypertension but also in healthy and diseased humans. Thus, these experimental and clinical studies highlight the potential of polyphenol-rich sources to provide vascular protection in health and disease.     

Soft tissue sarcomas with non-EWS translocations: molecular genetic features and pathologic and clinical correlations

Many soft tissue sarcoma subtypes have consistent chromosomal translocations with novel fusion genes, which result in disordered cellular function. The microscopic appearances, immunophenotype and behaviour of such tumours relate to the genetic events to a variable extent. This paper reviews the molecular pathology and related morphological and clinical features of sarcomas with non-EWS translocations. These include synovial sarcoma, alveolar rhabdomyosarcoma, alveolar soft part sarcoma, dermatofibrosarcoma protuberans, low-grade fibromyxoid sarcoma, infantile fibrosarcoma and inflammatory myofibroblastic tumour.     

Progressive adaptation of the soleus H-reflex with daily training at walking backward

When untrained subjects walk backward on a treadmill the amplitude of the soleus H-reflex in midswing is equal to or exceeds the value in stance. This is a surprising result because during the swing phase of backward walking the soleus is inactive and its antagonist, the tibialis anterior, is active. We suggested that the high amplitude of the soleus H-reflex in late swing reflects task uncertainties, such as estimating the moment of foot contact with the ground and losing balance. In support of this idea we show that when untrained subjects held on to handrails the unexpected high-amplitude H-reflex during midswing was no longer present. We therefore asked whether daily training at this task without grasping the handrails would adaptively modify the H-reflex modulation pattern. In this event, within 10 days of training for 15 min daily, the anticipatory reflex activity at the beginning of training was gradually abated as the subjects reported gaining confidence at the task. However, when adapted subjects were made to walk backward with their eyes shut, the anticipatory reflex activity in midswing returned immediately. The reflex changes as a result of training were not due to changes in the motor activity or kinematics; they are likely part of the motor program controlling backward walking. This adaptive phenomenon may prove to be a useful model for studying the neural mechanisms of motor learning and adaptive plasticity in humans and may be relevant to rehabilitation programs for neurological patients.     

Using EMGs and kinematics data to study the take-off technique of experts and novices for a pole vaulting short run-up educational exercise

This study attempts to characterise the electromyographic activity and kinematics exhibited during the performance of take-off for a pole vaulting short run-up educational exercise, for different expertise levels. Two groups (experts and novices) participated in this study. Both groups were asked to execute their take-off technique for that specific exercise. Among the kinematics variables studied, the knee, hip and ankle angles and the hip and knee angular velocities were significantly different. There were also significant differences in the EMG variables, especially in terms of (i) biceps femoris and gastrocnemius lateralis activity at touchdown and (ii) vastus lateralis and gastrocnemius lateralis activity during take-off. During touchdown, the experts tended to increase the stiffness of the take-off leg to decrease braking. Novices exhibited less stiffness in the take-off leg due to their tendency to maintain a tighter knee angle. Novices also transferred less energy forward during take-off due to lack of contraction in the vastus lateralis, which is known to contribute to forward energy transfers. This study highlights the differences in both groups in terms of muscular and angular control according to the studied variables. Such studies of pole vaulting could be useful to help novices to learn expert's technique.     

Distribution of ENG and ACVRL1 (ALK1) mutations in French HHT patients

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disease characterized by arteriovenous malformations and resulting from mutations in two major genes: ENG and ACVRL1. The aim of the present study was to estimate the prevalence of the mutations of ENG and ACVRL1 in HHT, based on the largest series of patients reported so far, recruited through a national network. We previously reported the first mutation screening of both genes, in French HHT patients, using heteroduplex analysis. This previous study, bringing 60 novel mutations, provided a significant improvement to the knowledge of molecular pathology in HHT. However, 32% (n=48) of the patients with a confirmed clinical diagnosis remained without mutation. In these patients, we performed an extensive molecular analysis that included the sequencing of the whole coding sequence, the search for large rearrangements, and screening of the potential 5' regulatory regions. Additionally, due to the lack of large pedigrees suitable for linkage analysis, and since SMAD4 germline mutations have been reported in families with combined HHT and juvenile polyposis, we screened this gene and five other genes involved in the TGF-beta/BMP pathway in the patients without mutation of ENG or ACVRL1. Only a novel SMAD1 non-conservative substitution was found in one patient, changing a poorly conserved methionine to an isoleucin. Twenty-three mutations were found in ACVRL1 and 8 in ENG (including a duplication of exons 4 to 8 and deletions of exons 1 to 3 and 9 to 14). Our results, combined with our previous data, increase the mutation rate to 88% (n=119/136) in French patients with a confirmed clinical diagnosis. Our results also emphasize the higher prevalence of large insertions/deletions in ENG and the predominance of ACVRL1 over ENG mutations.