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Landrum B. Shettles

Other affiliations: University of Colorado Denver
Bio: Landrum B. Shettles is an academic researcher from Columbia University. The author has contributed to research in topics: Polar body & Zona pellucida. The author has an hindex of 16, co-authored 43 publications receiving 2314 citations. Previous affiliations of Landrum B. Shettles include University of Colorado Denver.

Papers
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Journal ArticleDOI
TL;DR: Methods for obtaining and studying living follicular and tubal ova by means of phase contrast microscopy and the constitutents of the zona pellucida and perivitelline space are presented.

54 citations

Journal ArticleDOI
TL;DR: Many of the nuclei of the intermitotic cells from all of the fluids in which female infants developed contained the characteristic sex chromatin mass; i was not observed in any of theuclei of cells from amniotic fluids associated with male offspring.

54 citations

Journal Article
TL;DR: Observations on dried, unstained smears of human spermatozoa in phase contrast are made in an attempt to gain more insight into the basis for the known differential in conception and birth sex ratios.

41 citations


Cited by
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Book ChapterDOI
TL;DR: This chapter discusses the procedures employed for the analysis of the sugar components of glycoproteins, and the hydrolytic release of the monosaccharides is also considered.
Abstract: Publisher Summary This chapter discusses the procedures employed for the analysis of the sugar components of glycoproteins. Most of the methods used for the estimation of the monosaccharides present in glycoproteins are colorimetric in nature. Because of the relatively low specificity of some of these color reactions, it is often important to apply them only after appropriate separation of the constituents. In many cases complete identification, preferably by chromatographic means, of all the sugar and amino acid constituents of a glycoprotein should precede any colorimetric analysis so that potentially interfering substances may be taken into account. The hydrolytic release of the monosaccharides is also considered in the chapter. The optimal conditions of acid hydrolysis for the monosaccharides vary substantially because of differences both in the stability of their glycosidic bonds and in their susceptibility to destruction during the hydrolysis. One of the prerequisites for an accurate analysis of the monosaccharide components of a polymer is finding hydrolysis conditions under which all of a given sugar is released and yet is not significantly destroyed.

1,231 citations

Book ChapterDOI
TL;DR: This chapter discusses the chemical analysis of microbial cells and wet- and dry-weight determinations of bacterial samples and assay of total cell numbers are described, because analytical results must refer to one or other of these values.
Abstract: Publisher Summary This chapter discusses the chemical analysis of microbial cells. The preparation of material for analysis is discussed, because changes in the chemical composition of cells may occur as a result of the washing and storage conditions used. Wet- and dry-weight determinations of bacterial samples and assay of total cell numbers are described, because analytical results must refer to one or other of these values. Selection of an analytical procedure is a subjective process, because the number of suitable methods is large and each will have different merits and defects. Primary considerations are sensitivity, specificity, reproducibility, and absolute accuracy. Automatic methods for performing biochemical analyses, already widely accepted in hospitals and in industry, are beginning to make their way into the research laboratory. All automatic analyzers developed so far may be classified as either “continuous-flow” or “discrete” types. All of them use colorimetric methods exclusively and contain some form of automatic colorimeter for final read-out. The first and best-known is the Technicon “AutoAnalyzer,” which is of the continuous-flow type.

1,193 citations

Book ChapterDOI
TL;DR: In this article, a procedure for the calorimetric analysis of sugars for the identification and determination of small quantities of carbohydrates obtained from biological materials is presented, which is based on the Ihl-Pechmann reaction for fructose and is not to be confused with the diphenylamine test for DNA.
Abstract: Publisher Summary This chapter presents a procedure for the calorimetric analysis of sugars for the identification and determination of small quantities of carbohydrates obtained from biological materials. In general, such tests have been devised by heating aqueous solutions of the sugar with a strong acid, thereby converting it to furfural or a derivative of furfural. A color is then produced by the addition of an organic developer such as indole, orcinol, diphenylamine, or carbazole. Many of the reagents commonly employed for the determination of a specific class of sugars are suitable, with slight modifications, to measure total carbohydrates. Thus, orcinol, carbazole, indole, and diphenylamine have all been used for this purpose. Although these reactions logically require a separate classification, therefore they are discussed individually to prevent unnecessary duplication. For the determination of inulin diphenylamine reaction is employed, which is based on the Ihl-Pechmann reaction for fructose and is not to be confused with the diphenylamine test for DNA. In arsenomolybdate method of Nelson a colorimetric determination of the reaction product replaces the conventional iodometric titration of the reduced copper found in the Somogyi reagent, thus facilitating the handling of serial assays. In addition to the methods discussed in the chapter for the determination of pentoses, there are several alternate procedures which may be of value under special circumstances. The more important of these seem to be the methods of Roe and Rice and of Tracey employing p-bromoaniline and aniline, respectively, as the color-producing agent. These reactions are appreciably less affected by the presence of hexoses and uronic acids than is the case with orcinol.

978 citations

Posted Content
TL;DR: In this article, the authors provide a coherent perspective on the complex nutritional, economic, social and political issues involved in the causation of hunger and deprivation, and provide an integrated view of the role of public action in eliminating hunger.
Abstract: This study was well-received and widely discussed when it appeared in hardback in 1990. It is devoted to analysis of the enduring problem of hunger in the modern world, and of the role that public action can play in countering it. The book is divided into four parts. The first attempts to provide a coherent perspective on the complex nutritional, economic, social and political issues involved in the causation of hunger and deprivation. The second deals with famine prevention, paying special attention to Africa and India. The third focuses on chronic undernourishment and related deprivations. Parts two and three include a number of case studies of successful public action for the prevention of hunger and famines in various parts of the world. The fourth part of the book draws together the main themes and concerns of the earlier chapters, and provides an integrated view of the role of public action in eliminating hunger.

922 citations