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Biomedical subjects

G Eglinton

Publications and source records attributed to G Eglinton.

17 recordsLinked to original sources
PubMed1995

Prenatal diagnosis of partial trisomy through in situ hybridization on amniocytes with whole chromosome and centromere-specific DNA probes. A case report.

BACKGROUND: DNA probes specific for whole chromosomes or portions of chromosomes can provide important information to aid the clinician in managing pregnancy and the geneticist in relaying accurate recurrence risk information to the patient. CASE: In this case, sonography was ordered because of a low fundal height in a 29-year-old primigravida at 35 weeks' gestational age; it revealed major fetal anomalies. A small supernumerary marker was seen in some cultured amniocytes. Metaphase spreads were analyzed by means of fluorescence in situ hybridization using a centromere probe specific for chromosome 22 and a whole chromosome probe for the 11 chromosome. In situ hybridization showed that the marker chromosome was a derivative of chromosome 22 with 11q material attached near the centromere. The fetal karyotype was 47,XY,+der(22) t(11;22)(q23.3;q11.2)mat. The mother was later found to be a balanced translocation carrier. CONCLUSION: It was possible to offer rapid prenatal diagnosis for this family using interphase analysis with the 22 centromere probe. The patient had chorionic villus sampling, and DNA probes were used to analyze cells directly from the biopsy. The signal representing the supernumerary marker was not observed. Karyotype analysis later showed that the fetus was normal but a translocation carrier. This report illustrates that rapid in situ hybridization can provide important information in known cases of translocation carriers.

Adult↗
PubMed1991

Molecular preservation.

The differing patterns of molecular abundances in organisms are fundamental to the understanding of the biomolecular palaeontological record. All organisms contain DNA, RNA, protein, polysaccharides and lipid components, together with glycolipids, lipopolysaccharides and other complex molecules. Certain biopolymers, however, are restricted in their distributions; for example, lignin, cutin and sporopollenin are found only in terrestrial plants. The detailed chemical structures, namely the bond types present and their precise intramolecular environments, determine resistance to degradation. Observations of biomolecular preservation are compared with predictions based on chemical structure and on conditions encountered during decay.

Carbohydrates↗
PubMed1981

Specific acyclic isoprenoids as biological markers of methanogenic bacteria in marine sediments.

The widespread occurrence of extended hopanoids in sediments and petroleums illustrates the importance of bacterial lipid contributions to geological materials. In archaebacteria, however, hopanoids are absent; their role as structural components of biomembranes is fulfilled by acyclic isoprenoids. Recent studies of the lipid constituents of archaebacteria have greatly extended the range of acyclic isoprenoid skeletons known in organisms (Fig. 1). In particularly, isoprenoids with head-to-head linkages have been identified, and such compounds (for example, 3,7,11,15,18,22,26,30-octamethyldotriacontane, I) have been recognized in petroleum and as degradation products of Messel shale kerogen. Here we report the first recognition of 2,6,10,15,19-pentamethyleicosane (II), a known component of methanogens, in marine sediments of Recent to Cretaceous age (Table 1) and suggest that it and certain other acyclic isoprenoids may be used as biological markers for methanogens.

Euryarchaeota↗
PubMed1979

Application of combined liquid chromatography/mass spectrometry (LC/MS): analysis of petroporphyrins and meibomian gland waxes.

Application of the moving belt LC/MS interface is illustrated by two diverse examples, one from the field of petroporphyrin chemistry, the other, a sample of high molecular weight waxes from the steer meibomian gland (eye). Petroporphyrins are difficult of convert to derivatives suitable for GC analysis and the advantages of analysis by a combined separation/identification method are well demonstrated by the LC/MS runs. High molecular weight waxes can be saponified and derivatized for other analyses such as GC and GC/MS, but information regarding the distribution of alcohol and acid in the combined state is destroyed. This study shows that such information can be obtained by a combined LC/MS analysis without chemical manipulation of the sample.

Animals↗
PubMed1967

Leaf epicuticular waxes.

The external surface of the higher plants comprises a cuticular layer covered by a waxy deposit. This deposit is believed to play a major part in such phenomena as the water balance of plants and the behavior of agricultural sprays. The wax contains a wide range of organic compounds. These complex mixtures are amenable to modern microchromatographic and microspectrometric analytical procedures. The few surveys which have been made of the species distribution of certain classes of constituents indicate that such distribution may be of limited taxonomic value; however, the wax composition of a species may differ for different parts of the same plant and may vary with season, locale, and the age of the plant. This fascinating subject, in which the disciplines of botany, biochemistry, chemistry, and physics overlap and interact, is still in a very active state. Much remains to be learned about the composition and fine structure of the wax deposits, and, for this, experimental study of wax crystallization and permeation through artificial membranes will be required. Enzymic studies, radiolabeling, and electron microscopy will be needed to reveal the mode of biogenesis of the wax constituents and their site of formation and subsequent pathway through the cuticle to the leaf surface.

Aldehydes↗
PubMedDate not supplied

Application of real-time mass spectrometric techniques to environmental organic geochemistry. I. Computerized high resolution mass spectrometry and gas chromatography-low resolution mass spectrometry.

LOGOS (Smith et al. 1971), an integrated mass spectrometer/computer system, has been employed in a series of experiments which illustrate the utility of the automated techniques of real-time mass spectrometry in the study of organic compounds in the environment. These techniques are shown to be particularly useful in resolving complex mixtures of organic compounds encountered in environmental studies. Complete high resolution mass spectrometry, particularly when used in conjunction with combined gas chromatography/mass spectrometry, and auxiliary techniques such as stable isotopic labeling are described to illustrate the type and scope of information that may be obtained. Illustrative samples include extracts of air- and waterborne particulates, extracts of water-soluble organic material, and a DDT metabolite from sewage sludge.

Air↗