81 research outputs found

    Nevoid basal cell carcinoma syndrome (Gorlin syndrome)

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    Nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome, is a hereditary condition characterized by a wide range of developmental abnormalities and a predisposition to neoplasms

    The pancreas in human type 1 diabetes

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    Type 1 diabetes (T1D) is considered a disorder whose pathogenesis is autoimmune in origin, a notion drawn in large part from studies of human pancreata performed as far back as the 1960s. While studies of the genetics, epidemiology, and peripheral immunity in T1D have been subject to widespread analysis over the ensuing decades, efforts to understand the disorder through analysis of human pancreata have been far more limited. We have reviewed the published literature pertaining to the pathology of the human pancreas throughout all stages in the natural history of T1D. This effort uncovered a series of findings that challenge many dogmas ascribed to T1D and revealed data suggesting the marked heterogeneity in terms of its pathology. An improved understanding and appreciation for pancreatic pathology in T1D could lead to improved disease classification, an understanding of why the disorder occurs, and better therapies for disease prevention and management

    Novel 5-(4-substituted-phenyldiazenyl)-1,3,2 lambda(4)-oxazaborines and their rearrangement to 1,2,4,3 lambda(4)-triazaborines

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    The reaction of substituted benzenediazonium tetraphenylborates with the beta-enaminones derived from pentane-2,4-dione, 1-phenylbutane-1,3-dione, and 1,4-diphenylbutane-1,3-dione with a primary or secondary (N-methyl, N-phenyl) amino group in CH2Cl2 gives 5-(substituted-phenyldiazenyl)-2,2-diphenyl-4,6-disubstituted- 1,3,2 lambda(4)-oxazaborines or 5-(substituted-phenyldiazenyl)-2,2-diphenyl-3,4,6-trisubstituted-1,3,2 lambda(4)- oxazaborines, respectively. The reaction intermediate of these compounds has been identified, and a mechanism for the reaction has been suggested. Substituted 1,3,2 lambda(4)-oxazaborines gradually rearrange into 1,2,4,3 lambda(4)-triazaborines at temperatures above 100 degrees C

    Structure and reactivity of 3,3-disubstituted 1-(5-nitro-2,1-benzisothiazol-3-yl)triazenes

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    The reaction between 5-nitro-2,1-benzisothiazole-3-di- azonium species and N-substituted anilines produces the 1- (5-nitro-2,1-benzisothiazol-3-yl)-3,3-disubstituted triazenes 1. These triazenes are highly stable, and even in strongly acidic medium (0.5 molL−1 H2SO4) they are only slowly de- composed back to the diazonium ion and substituted anilin- ium ion (for the N-ethyl derivative in 0.5 mol·L−1 H2SO4 at 25 °C, t1/2 7 h). A series of six triazenes were characterised by their 1H and 13C NMR spectra and mass spectra. Two of the triazenes were also identified by X-ray crystallography

    Solution and solid state structure and tautomerism of azo coupled enaminone derivatives of benzoylacetone

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    The reaction of 4-substituted benzenediazonium tetrafluoroborates with 3-amino-1-phenylbut-2-en-1-one, 4-amino-4-phenylbut-3-en-2-one and their N-aryl derivatives 1a-1g has been used to prepare the respective azo coupling products i.e. compounds 2-5 from enaminone 1a, compounds 6-9 from enaminone 1c, compound 10 from enaminone 1d, compound 11 from enaminone 1e, compounds 12, 13 from enaminone 1f, compounds 14, 15 from enaminone 1b and compound 16 from enaminone 1g. Tautomerism of the azo coupling products prepared has been investigated in CDCl3 solutions by means of H-1, C-13 and N-15 NMR spectra. Crystal structures of selected products have also been investigated by means of X-ray diffraction

    Formation of pyridazinium salts by azo coupling of N-substituted 3-amino-1-phenylbut-2-en-1-ones and diazonium salts

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    Treatment of 3-(2,4-dimethoxyphenylamino)- and 3-methylamino-1-phenylbut-2-en-1-ones with some benzenediazonium tetrafluoroborates gives, besides the usual azo coupling products [i.e., 3-(substituted imino)-1-phenylbutane-1,2-di-ones 2- (4-substituted phenylhydrazones) and 2-(4-methoxy-phenyldiazenyl)-3-methylamino-1-phenylbut-2-en-1-one, respectively], the previously unreported 1,4,5,6-tetrasubstituted pyridazinium tetrafluoroborates. The pyridazinium salts have been identified by X-ray analysis and by their H-1, C-13, N-15, B-11 and F-19 NMR spectra. Their formation is most probably the result of nucleophilic attack on the carbonyl carbon by the nitrogen of the hydrazone group and subsequent dehydration

    <span style="font-size:12.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-ansi-language: EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:AR-SA" lang="EN-IN">A synthetic and stereochemical study of 2,6- diaroyl-3,5-diaryltetrahydro- 1,4-thiazine-1,1-dioxides</span>

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    962-963<span style="font-size:12.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-in;mso-fareast-language:en-in;mso-bidi-language:ar-sa"="" lang="EN-IN">Aza-Michael addition of ammonia to 2,2'-sulfonylbis(1,3-diarylprop-2-en-1-ones) in dimethylformamide afford 2,6-diaroyl-3,5-diaryltetrahydro-1 ,4-thiazine-1, 1-dioxides in excellent yields. The structure and stereochemistry of the compounds have been deduced from elemental analysis and spectral data.</span

    Synthesis, NMR and X-ray characterisation of 6-substituted 4-amino-5-aryldiazenyl-1-arylpyridazinium salts

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    A new simple method has been used to prepare 6-substituted 4-(subst. amino)-5-aryldiazenyl-l-arylpyridazinium salts from N-methyl- or N-aryl-3-amino-l-phenylbut-2-en-l-ones and 4-aminopent-3-en-2-ones and substituted benzenediazonium tetrafluoroborates or hexafluorophosphates. The structure of selected derivatives was studied by means of N-15 NMR spectra and X-ray
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