Ten cases of adrenal adenomas, one case with unilateral adrenal hyperplasia, and another case with apparent bilateral are reported, in whom an alternative pathway of aldosterone via ...21-deoxyaldosterone is operative. They all manifested hypertension, low renin activity, low normal potassium values, as well as high urinary excretion rates of 21-deoxyaldosterone and its related metabolite Kelly's-M1 steroid. In all cases, urinary aldosterone metabolites (aldosterone-18-glucuronide and tetrahydroaldosterone) and aldosterone precursor 18-hydroxycorticosterone levels were normal. Hence, the adrenal lesions give rise to hyper-21-deoxyaldosteronism. 21-Deoxyaldosterone is a weak mineralocorticoid, and its elevated production in the presence of normal aldosterone can induce a pathological state of hypermineralocorticoidism. Adrenalectomy resulted in normalization of hypertension in six of eight and amelioration in two of eight cases. Six of seven adenoma cases examined as well as the case of unilateral adrenal hyperplasia were sensitive to ACTH. One of the seven adenomas and, as expected, the case with apparent bilateral hyperplasia were angiotensin responsive. Histologically and electron microscopically, the operated adenomas consisted predominantly of clear cells, characterized by mitochondria with tubulo-vesicular internal structure similar to those of the zona fasciculata (in contrast, our classical Conn's adenoma with normal 21-deoxyaldosterone excretion exhibited a more heterogenous histological appearance and were, in terms of ultrastructure, more similar to cells of the zona glomerulosa). Ultrastructurally and immunocytochemically, the clear cells of 21-deoxyaldosterone adenomas showed features of both the zona glomerulosa and the zona fasciculata and are, hence, considered to be hybrid cells. We conclude that the determination of 21-deoxyaldosterone and Kelly's-M1 should be considered in the diagnosis of mineralocorticoid-induced forms of hypertension, especially when an adrenal adenoma has been detected with an imaging procedure.
The Ds-induced unstable sh-m6258 allele is caused by the insertion of at least 45 kb of non-sh DNA. Genomic clones spanning the two junctions of sh sequences with insert sequences were isolated and ...analysed. The long insert in the sh-m6258 allele is bordered by Ds sequences on either side. A 3 kb double Ds structure which consists of one complete Ds element of approximately 2 kb and one half Ds element of approximately 1 kb was found in the sh-m6258 allele at the junction between the 3' region of the sh locus and the insert. At the junction between the 5' region of the sh locus and the insert a half Ds element is present. This truncated Ds element was probably left behind after the excision of a 2 kb Ds element from a 3 kb double Ds structure similar to that found at the 3' junction. Sequence analysis of the insert sequences beyond the Ds elements demonstrated that the long inserts in both the sh-m6258 and the sh-m5933 alleles originated from the same contiguous chromosomal segment in their common progenitor strain. One revertant derivative of the sh-m6258 allele was investigated. In the revertant strain, which displays a normal non-shrunken phenotype, a 2 kb Ds element is present at the site of the 45 kb insert in the mutant allele. This 2 kb insertion, which is located in the last but one intervening sequence of the Sh gene, does not inhibit expression of the gene.
The authors describe a case of cerebellar abscess by Nocardia in a patient with the acquired immunodeficiency syndrome (AIDS) that was submitted to a posterior fossa craniectomy for diagnosis and ...treatment. Pathological and neuroimage findings are discussed as well as the surgical approach taking into account literature data on the subject.
E-learning is now a prominent form of education that allows for the creation of tailored solutions for different learning styles and requirements. An essential element of e-learning, learning ...technology systems manage the learning environment, learning objects, and resource infrastructures. Architecture Solutions for E-Learning Systems provides fundamental research on the architecture of learning technology systems, discussing such issues as the common structures in LTS architectures and solutions for specific forms such as knowledge-based, distributed, or adaptive applications of e-learning. Researchers, practitioners, and scholars in the fields of learning content software development, computing and educational technologies, and e-learning will find this book an invaluable resource.
E-learning is now a prominent form of education that allows for the creation of tailored solutions for different learning styles and requirements. An essential element of e-learning, learning technology systems manage the learning environment, learning objects, and resource infrastructures. Architecture Solutions for E-Learning Systems provides fundamental research on the architecture of learning technology systems, discussing such issues as the common structures in LTS architectures and solutions for specific forms such as knowledge-based, distributed, or adaptive applications of e-learning. Researchers, practitioners, and scholars in the fields of learning content software development, computing and educational technologies, and e-learning will find this book an invaluable resource.
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