254 research outputs found

    (1E,2E)-1,2-Bis(2,2-diphenyl­hydrazin-1-yl­idene)ethane

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    In the crystal structure of the title compound, C26H22N4, the mol­ecule is located on an inversion centre and shows an E configuration with respect to each C=N bond. The dihedral angle between the phenyl rings in the diphenyl­hydrazone group is 83.69 (11)°. These two rings make dihedral angles of 30.53 (15) and 84.53 (16)° with the central N—N=C—C=N—N dihydrazonoethane plane. Inter­molecular C—H⋯π inter­actions are observed

    Multifractal properties of return time statistics

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    Fluctuations in the return time statistics of a dynamical system can be described by a new spectrum of dimensions. Comparison with the usual multifractal analysis of measures is presented, and difference between the two corresponding sets of dimensions is established. Theoretical analysis and numerical examples of dynamical systems in the class of Iterated Functions are presented.Comment: 4 pages, 3 figure

    N′-[5-(4-Nitro­phen­yl)furan-2-yl­methyl­idene]-N,N-diphenyl­hydrazine

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    The title compound, C23H17N3O3, has an E configuration with respect to the C=N bond. The dihedral angle between the two phenyl rings bonded to the hydrazine group is 86.45 (13)°. The furan ring makes dihedral angles of 3.4 (2) and 7.06 (13)°, respectively, with the methyl­idenehydrazine C=N—N plane and the benzene ring

    (E)-1-(3,4-Dimethyl­benzyl­idene)-2,2-diphenyl­hydrazine

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    The asymmetric unit of the title compound, C21H20N2, contain two mol­ecules, both of them showing an E configuration of the C=N bond. The dihedral angles between the phenyl rings in the phenyl­hydrazone groups are 86.84 (10) and 84.85 (8)° for the two mol­ecules. Inter­molecular C—H⋯π inter­actions are observed in the crystal structure

    Agouti signalling protein is an inverse agonist to the wildtype and agonist to the melanic variant of the melanocortin-1 receptor in the grey squirrel (Sciurus carolinensis)

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    The melanocortin-1 receptor (MC1R) is a key regulator of mammalian pigmentation. Melanism in the grey squirrel is associated with an eight amino acid deletion in the mutant melanocortin-1 receptor with 24 base pair deletion (MC1RΔ24) variant. We demonstrate that the MC1RΔ24 exhibits a higher basal activity than the wildtype MC1R (MC1R-wt). We demonstrate that agouti signalling protein (ASIP) is an inverse agonist to the MC1R-wt but is an agonist to the MC1RΔ24. We conclude that the deletion in the MC1RΔ24 leads to a receptor with a high basal activity which is further activated by ASIP. This is the first report of ASIP acting as an agonist to MC1R

    (E)-1-Benzyl­idene-2,2-diphenyl­hydrazine

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    The asymmetric unit of the title compound, C19H16N2, contains two independent mol­ecules, both of which show an E configuration with respect to the C=N bond. The dihedral angles between the phenyl rings bonded to the hydrazine group are 81.00 (10) and 88.34 (8)° in the two mol­ecules. Inter­molecular C—H⋯π inter­actions are observed in the crystal structure

    Identification of Tetrapeptides from a Mixture Based Positional Scanning Library That Can Restore nM Full Agonist Function of the L106P, I69T, I102S, A219V, C271Y, and C271R Human Melanocortin-4 Polymorphic Receptors (hMC4Rs)

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    Human obesity has been linked to genetic factors and single nucleotide polymorphisms (SNPs). Melanocortin-4 receptor (MC4R) SNPs have been associated with up to 6% frequency in morbidly obese children and adults. A potential therapy for individuals possessing such genetic modifications is the identification of molecules that can restore proper receptor signaling and function. These compounds could serve as personalized medications improving quality of life issues as well as alleviating diseases symptoms associated with obesity including type 2 diabetes. Several hMC4 SNP receptors have been pharmacologically characterized in vitro to have a decreased, or a lack of response, to endogenous agonists such as α-, β-, and γ2-melanocyte stimulating hormones (MSH) and adrenocorticotropin hormone (ACTH). Herein we report the use of a mixture based positional scanning combinatorial tetrapeptide library to discover molecules with nM full agonist potency and efficacy to the L106P, I69T, I102S, A219V, C271Y, and C271R hMC4Rs. The most potent compounds at all these hMC4R SNPs include Ac-His-(pI)DPhe-Tic-(pNO2)DPhe-NH2, Ac-His-(pCl)DPhe-Tic-(pNO2)DPhe-NH2, Ac-His-(pCl)DPhe-Arg-(pI)Phe-NH2, and Ac-Arg-(pCl)DPhe-Tic-(pNO2)DPhe-NH2, revealing new ligand pharmacophore models for melanocortin receptor drug design strategies

    Regulatory T cells inhibit CD34+ cell differentiation into NK cells by blocking their proliferation

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    Graft versus Host Disease (GvHD) remains one of the main complications after hematopoietic stem cell transplantation (HSCT). Due to their ability to suppress effector cells, regulatory T cells (Tregs) have been proposed as a cellular therapy to prevent GvHD, however they also inhibit the functions of natural killer (NK) cells, key effectors of the Graft versus Leukemia effect. In this study, we have explored whether a Tregs therapy will also impact on NK cell differentiation. Using an in vitro model of hematopoietic stem cell (HSC) differentiation into NK cells, we found that activated Tregs led to a 90% reduction in NK cell numbers when added at the time of commitment to the NK cell lineage. This effect was contact dependent and was reversible upon Tregs depletion. The few NK cells that developed in these cultures were mature and exhibited normal functions. Furthermore, adoptive transfer of activated Tregs in rag(-/-) γc(-/-) mice abrogated HSC differentiation into NK cells thus confirming our in vitro findings. Collectively, these results demonstrate for the first time that activated Tregs can inhibit NK cell differentiation from HSC under specific conditions

    Prevalence of pathogenetic MC4R mutations in Italian children with early onset obesity, tall stature and familial history of obesity.

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    BackgroundMelanocortin-4-receptor (MC4R) mutations represent the most frequent genetic cause of non-syndromic early onset obesity. Children carrying MC4R mutations seem to show a particular phenotype characterized by early onset, severe obesity and high stature. To verify whether MC4R mutations are associated with this particular phenotype in the Italian pediatric population, we decided to screen the MC4R gene in a group of obese children selected on the basis of their phenotype.MethodsTo perform this study, a multicentric approach was designed. Particularly, to be enrolled in the study subjects needed to meet the following criteria: Body mass index ≥ 3 deviation scores according to age and sex, familiar history of obesity (at least one parent obese), obesity onset before the 10 years old, height ≥ 2 deviation scores. The coding region of MC4R gene was screened in 240 obese children (mean age 8.3 ± 3.1, mean BMI 30.8 ± 5.4) and in 200 controls (mean age 8.1 ± 2.8; mean BMI 14.2 ± 2.5).ResultsThree mutations have been found in five obese children. The S127L (C380T), found in three unrelated children, had been described and functionally characterized previously. The Q307X (C919T) and the Y332H (T994C) mutations were found in two patients. Functional studies showed that only Q307X impaired protein function.ConclusionThe low prevalence of MC4R mutations (1.6%) in this group of obese children selected according to the obesity degree, the tall stature and the family history of obesity was similar to the prevalence observed in previous screenings performed in obese adults and in not phenotypically selected obese children
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