Thickness of softened human enamel removed by toothbrush abrasion: an in vitro study

The aim of the study was to assess the thickness of softened enamel removed by toothbrushing. Human enamel specimens were indented with a Knoop diamond. Softening was performed with citric acid or orange juice. The specimens were brushed in a brushing machine with a manual soft toothbrush in toothpaste slurry or in artificial saliva. Enamel loss was calculated from the change in indentation depth of the same indent before and after abrasion. Mean surface losses (95% confidence interval) were recorded in treatment groups (in nanometers): (1) citric acid, abrasion with slurry = 339 (280-398); (2) citric acid, abrasion with artificial saliva = 16 (5-27); (3) orange juice, abrasion with slurry = 268 (233-303); (4) orange juice, abrasion with artificial saliva = 14 (5-23); (5) no softening, abrasion with slurry = 28 (10-46). The calculated thickness of the softened enamel varied between 254 and 323 nm, depending on the acid used.

Characterization of Molecular Determinants of the Conformational Stability of Macrophage Migration Inhibitory Factor: Leucine 46 Hydrophobic Pocket

Macrophage Migration Inhibitory Factor (MIF) is a key mediator of inflammatory responses and innate immunity and has been implicated in the pathogenesis of several inflammatory and autoimmune diseases. The oligomerization of MIF, more specifically trimer formation, is essential for its keto-enol tautomerase activity and probably mediates several of its interactions and biological activities, including its binding to its receptor CD74 and activation of certain signaling pathways. Therefore, understanding the molecular factors governing the oligomerization of MIF and the role of quaternary structure in modulating its structural stability and multifunctional properties is crucial for understanding the function of MIF in health and disease. Herein, we describe highly conserved intersubunit interactions involving the hydrophobic packing of the side chain of Leu46 onto the β-strand β3 of one monomer within a hydrophobic pocket from the adjacent monomer constituted by residues Arg11, Val14, Phe18, Leu19, Val39, His40, Val41, Val42, and Pro43. To elucidate the structural significance of these intersubunit interactions and their relative contribution to MIF’s trimerization, structural stability and catalytic activity, we generated three point mutations where Leu46 was replaced by glycine (L46G), alanine (L46A) and phenylalanine (L46F), and their structural properties, stability, oligomerization state, and catalytic activity were characterized using a battery of biophysical methods and X-ray crystallography. Our findings provide new insights into the role of the Leu46 hydrophobic pocket in stabilizing the conformational state of MIF in solution. Disrupting the Leu46 hydrophobic interaction perturbs the secondary and tertiary structure of the protein but has no effect on its oligomerization state.

Impact of estrogen replacement throughout childhood on growth, pituitary-gonadal axis and bone in a 46,XX patient with CYP19A1 deficiency

The adequate replacement dose of estrogens during infancy and childhood is still not known in girls. Aromatase deficiency offers an excellent model to study how much estrogens are needed during infancy, childhood and adulthood.

Ten novel mutations in the NR5A1 gene cause disordered sex development in 46,XY and ovarian insufficiency in 46,XX individuals

Steroidogenic factor-1 (SF-1/NR5A1) is a nuclear receptor that regulates adrenal and reproductive development and function. NR5A1 mutations have been detected in 46,XY individuals with disorders of sexual development (DSD) but apparently normal adrenal function and in 46,XX women with normal sexual development yet primary ovarian insufficiency (POI).

Characterization of a novel CYP19A1 (aromatase) R192H mutation causing virilization of a 46,XX newborn, undervirilization of the 46,XY brother, but no virilization of the mother during pregnancies.

BACKGROUND P450 aromatase (CYP19A1) is essential for the biosynthesis of estrogens from androgen precursors. Mutations in the coding region of CYP19A1 lead to autosomal recessive aromatase deficiency. To date over 20 subjects have been reported with aromatase deficiency which may manifest during fetal life with maternal virilization and virilization of the external genitalia of a female fetus due to low aromatase activity in the steroid metabolizing fetal-placental unit and thus high androgen levels. During infancy, girls often have ovarian cysts and thereafter fail to enter puberty showing signs of variable degree of androgen excess. Moreover, impact on growth, skeletal maturation and other metabolic parameters is seen in both sexes. OBJECTIVE AND HYPOTHESIS We found a novel homozygous CYP19A1 mutation in a 46,XX girl who was born at term to consanguineous parents. Although the mother did not virilize during pregnancy, the baby was found to have a complex genital anomaly at birth (enlarged genital tubercle, fusion of labioscrotal folds) with elevated androgens at birth, normalizing thereafter. Presence of 46,XX karyotype and female internal genital organs (uterus, vagina) together with biochemical findings and follow-up showing regression of clitoral hypertrophy, as well as elevated FSH suggested aromatase deficiency. Interestingly, her older brother presented with mild hypospadias and bilateral cryptorchidism and was found to carry the same homozygous CYP19A1 mutation. To confirm the clinical diagnosis, genetic, functional and computational studies were performed. METHODS AND RESULTS Genetic analysis revealed a homozygous R192H mutation in the CYP19A1 gene. This novel mutation was characterized for its enzymatic activity (Km, Vmax) in a cell model and found to have markedly reduced catalytic activity when compared to wild-type aromatase; thus explaining the phenotype. Computational studies suggest that R192H disrupts the substrate access channel in CYP19A1 that may affect binding of substrates and exit of catalytic products. CONCLUSION R192H is a novel CYP19A1 mutation which causes a severe phenotype of aromatase deficiency in a 46,XX newborn and maybe hypospadias and cryptorchidism in a 46,XY, but no maternal androgen excess during pregnancy.

Klartraumtraining bei deutschen und japanischen Athleten: Eine Fragebogenstudie

Einleitung Eine eher unbekannte Art des Mentalen Trainings ist das Training im Klartraum (Erla-cher, Stumbrys & Schredl, 2011-12). Im Klartraum ist sich der Träumende bewusst, dass er träumt, und kann dadurch den fortlaufenden Trauminhalt kontrollieren. Frühere Stu-dien zeigten, dass es möglich ist, motorische Aufgaben im Klartraum zu üben, um dadurch eine verbesserte Leistung im Wachzustand zu erreichen (Erlacher & Schredl, 2010). Jedoch ist wenig über die Prävalenz von Klarträumern im Sport bekannt. Methode Die Stichprobe umfasste 840 deutsche (D: 483 m, 357 w) und 1323 japanische (J: 1000 m, 323 w) Athleten. Das Durchschnittsalter betrug 20,4 Jahre (D: 21,6 J: 19,7). Die Teil-nehmer wurden in verschiedenen Sportarten – von Mannschaftssportarten (z.B. Basket-ball) bis Einzelsportarten (z.B. Leichtathletik) – rekrutiert und füllten einen Fragebogen zum Thema Sport, Schlaf und Traum aus. Die Athleten waren durchschnittlich 9,1 Jahre (D: 11.1, J: 7,9) aktiv und trainierten etwa 14,4 Stunden (D: 11.1, J: 16,7) pro Woche. Der Fragebogen erfasste auf einer 8-stufigen Skala die Klartraumhäufigkeit (Plus Definition: Für ein klares Verständnis von Klarträumen); die Anwendung (z.B. Training) für den Sport und, wenn dies bestätigt wurde, ob sportliche Verbesserungen erlebten wurden. Ergebnisse 47% (D: 57%, J: 41%) der Athleten gaben an, mindesten einen Klartraum erlebt zu ha-ben, 20% (D: 24% J: 18%) sind häufige Klarträumer (mit einem oder mehrere Klarträume pro Monat) und 9% (D 9% , J: 9%) nutzen Klarträume für ihren Sport, davon berichtet die Mehrheit, dass das Klartraumtraining die sportliche Leistung im Wachzustand verbessert. Diskussion Etwa die Hälfte der Athleten kennt das Klarträumen aus eigener Erfahrung, ein Fünftel sind häufige Klarträumer und etwa jeder zehnte Athlet nutzt Klarträume für seinen Sport. Für die deutsche Stichprobe ist die Prävalenzrate der Athleten ähnlich wie in der Bevöl-kerung. Für die japanische Stichprobe liegen keine repräsentativen Bevölkerungsdaten vor, auf der Grundlage der hier vorgestellten Fragebogendaten scheint es jedoch, dass kulturellen Unterschiede eine untergeordnete Rolle spielen. Literatur Erlacher, D. & Schredl, M. (2010). Practicing a motor task in a lucid dream enhances subsequent perfor-mance: A pilot study. The Sport Psychologist, 24(2), 157-167. Erlacher, D., Stumbrys, T. & Schredl, M. (2011-2012). Frequency of lucid dreams and lucid dream practice in German athletes. Imagination, Cognition and Personality, 31(3), 237-246.

The role of FUS in splicing regulation

Fused in sarcoma (FUS), also called translocated in liposarcoma (TLS), is a ubiquitously expressed DNA/RNA binding protein belonging to the TET family and predominantly localized in the nucleus. FUS is proposed to be involved in various RNA metabolic pathways including transcription regulation, nucleo-cytosolic RNA transport, microRNA processing or pre-mRNA splicing [1]. Mutations in the FUS gene were identified in patients with familial amyotrophic lateral sclerosis (ALS) type 6 and sporadic ALS [2, 3]. ALS, also termed Lou Gehrig's disease, is a fatal adult-onset neurodegenerative disease affecting upper and lower motor neurons in the brain and spinal cord. There is increasing evidence supporting the hypothesis that FUS might play an important role in pre-mRNA splicing regulation. Several splicing factors were identified to associate with FUS including hnRNPA2 and C1/C2 [4], Y-box binding protein 1 (YB-1) [5] and serine arginine (SR) proteins (SC35 and TASR) [6]. Additionally, FUS was identified as a constituent of human spliceosomal complexes [1]. Our recent results indicate that FUS has increased affinity for certain but not all snRNPs of the minor and major spliceosome. Furthermore, in vitro studies revealed that FUS directly interacts with a factor specific for one of those snRNPs. These findings might uncover the molecular mechanism by which FUS regulates splicing and could explain previously observed effects of FUS on the splicing of the adenovirus E1A minigene [7] and changes in splicing caused by ALS associated FUS mutations. [1] Lagier-Tourenne C et al. (2010) Human Molecular Genetics 19:46-64 [2] Kwiatkowski TJ Jr et al. (2009) Science 323:1205-8 [3] Vance C et al. (2009) Science 323:1208-11 [4] Zinser H et al. (1994) Genes Dev 8:2513-26 [5] Chansky, H.A., et al. (2001) Cancer Res. 61: 3586-90. [6] Yang L et al. (1998) J Biol Chem 273:27761-6 [7] Kino Y et al. (2010) Nucleic Acid Research 7:2781-2798