Showing papers in "Advances in human genetics in 1979"

Terminological, Diagnostic, Nosological, and Anatomical-Developmental Aspects of Developmental Defects in Man

Abstract: Man’s experience of congenital malformations antedates recorded history and can be inferred from philology and the most ancient of legends. Indeed, the presence of Down syndrome in the chimpanzee (McClure et al., 1969, 1970) and of various X-linked disorders in other mammals (Ohno, 1967) means that even during phylogeny man lived side by side with mammalian cousins affected with homologous forms of his own genetic aberrations. The history of teratology has been written many times and is astoundingly voluminous (Gruber, 1964). It shows that the accomplishments of the early workers in the field consisted primarily of anatomical and clinical descriptions.

Genetic Aspects of Folate Metabolism

Abstract: Folic acid is an essential vitamin required for important steps in the synthesis of purines and pyrimidines, and in amino acid metabolism. Humans, in contrast to plants, bacteria, and yeast, are unable to synthesize folates de novo and thus depend on an adequate dietary supply of folates to the extent of at least 50 µg/day for nonpregnant adults (Herbert, 1971). Moreover, normal function requires that these dietary folates be properly absorbed, distributed throughout the organism, and used by cells.

Chromosomes and neoplasia.

Abstract: While it would be satisfying to find that the same cellular process, or even a group of closely related processes, leads to the development of neoplasia, there is no necessity to believe that such a common pathway exists, since cancer includes many diverse diseases, the etiology, biology, clinical presentation, therapy, and prognosis of which will differ very greatly. Our knowledge of cancer cells depends largely on the behavior of the cells in culture and the measurement of various parameters that are not necessarily linked in any causal way with the neoplastic state. From these studies, however, have arisen a number of theories on the nature of neoplasia. For example, it is quite clear that the cell surface of cancer cells is abnormal in many different ways.304 There are new antigenic determinants; there may be altered glycoprotein and sialoprotein structures on the cell surface; the electrical charge and therefore the electrophoretic mobility of the cells may be altered; the absence of some material from the cell surface may also be associated with the acquisition of neoplastic properties (e.g., LETS protein29). Cancer cells also have altered contact relationships with other cells in culture in that they will fail to respond to the presence of other cells and move over or under them, whereas normal cells will usually stop or change direction on coming into contact with other cells.

Human alphafetoprotein 1956-1978.

Abstract: Since its discovery in 1956, human alphafetoprotein (AFP) has been intensively studied, and although investigations of certain biological properties of AFP are still beset with contradictions and conjectures, there are now several important areas in which sound experimental evidence and clinical observations permit definitive conclusions.

Genetic mechanisms contributing to the expression of the human hemoglogin loci.

Abstract: To a greater extent than in any other protein system known, human hemoglobin loci have provided a rich field for the study of the molecular basis of phenotypic variability. At the protein level, over 300 human hemoglobin variants are known. Of these variants, more than 90% involve one of the two main chains, α and β, that comprise the adult form of hemoglobin (α 2 β 2). The balance are variants of the minor components, Hb F (α 2 γ 2) and Hb A2 (α 2δ2). Since variants usually reflect small, discrete abnormalities of primary structure, they have contributed greatly to our understanding of the forces that maintain tertiary and quaternary structure of the hemoglobin molecule and of the role of these structured features in gas transport.