PubMed Health⌕ Search

Biomedical subjects

A C Edman

Publications and source records attributed to A C Edman.

7 recordsLinked to original sources
PubMed1995

Helicobacter pylori and acute bleeding peptic ulcer.

OBJECTIVE: The prevalence of Helicobacter pylori in chronic peptic ulcer is well known. In this study the frequency of H. pylori infection was investigated in patients with acute bleeding peptic ulcer. DESIGN AND SETTING: Prospective study in a district hospital. PATIENTS: Seventy consecutive patients with acute bleeding peptic ulcer. INTERVENTIONS: Diagnosis was verified on admission by endoscopy, and healing was examined at follow-up. Previous history of ulcer disease, presence of dyspeptic symptoms and consumption of non-steroidal anti-inflammatory drugs were recorded. MAIN OUTCOME MEASURES: H. pylori infection was detected by two serological tests in samples obtained on admission for the acute bleeding episode, and at follow-up 1-3 months later. RESULTS: With a commercial latex immunoassay, 53% of the patients with gastric ulcer and 62% with duodenal ulcer were shown to possess H. pylori antibodies. In the other test, a standard enzyme-linked immunosorbent assay based on cell surface protein antigens of H. pylori with high sensitivity and specificity, 81% of gastric ulcer patients and 85% of duodenal ulcer patients were shown to have H. pylori antibodies. CONCLUSION: The results indicate that H. pylori infection plays a major aetiological role in patients with acute bleeding peptic ulcer.

Acute Disease↗
PubMed1991

Cryoultramicrotomy of muscle: improved preservation and resolution of muscle ultrastructure using negatively stained ultrathin cryosections.

Ultrathin sections of rapidly frozen, briefly pre-treated muscle tissue are cut and thereafter are thawed and contrasted using a negative staining technique. The method has provided micrographs in which the in-vivo order in the muscle fibres has been preserved well enough to enable both a more complete interpretation of X-ray diffraction evidence from muscle, and also a gain of new ultrastructural information on aspects of myofibril and myofilament architecture in different types of fibre. Examples here are taken from chicken, rabbit and fish muscles and show both the M-band and the bridge region of the A-band in great detail. To enhance the detail in the original images, one-dimensional (1-D) and 2-D averaging techniques (lateral smearing and step averaging, respectively) are used. Although there is major shrinkage in section thickness to about one-third of its original value, demonstrated here for the first time is the fact that the characteristic A-band lattice planes are preserved in these sections in 3-D. This confirms the usefulness of cryosections not just for 1-D and 2-D image processing, but also for 3-D reconstruction. Thus, in combination with techniques of image processing, cryoultramicrotomy can give the muscle morphologist the detailed data that are needed to match the molecular biologists, biochemists and immunologists in the interpretation of their data about physiological and pathophysiological events in muscle fibres at the macromolecular level.

Animals↗
PubMed1988

Structural diversity in muscle fibres of chicken breast.

Chicken breast muscle is usually considered to be a relatively homogeneous white muscle and has therefore been widely used for studies of muscle proteins. In a previous study, however, we have found different M-region structures in different fibres from this muscle. Because of this result, we have now carried out a combined histochemical and ultrastructural survey of this muscle. In particular, we have made use of large transverse cryo-sections that include most of the muscle cross-section. Although the white region is fairly homogeneous in fibre content according to normal histochemical criteria (mATPase), we have found that there is a gradation of fibre structure across the muscle. The bulk of the muscle stains conventionally for Type-II fibres according to mATPase tests (the "white" part) but, in the small "red" part of the muscle, there are also Type-I fibres together with the Type-II fibres. Superimposed on this division into Type-I and Type-II fibres are variations in fibre size, oxidative and glycolytic staining properties, and variations of Z-band width and M-band structure; there is no strict correlation among any of these parameters. The apparently uniform staining across most of the muscle when tested for myofibrillar ATPase may be a misleading indicator of fibre properties.

Adenosine Triphosphatases↗
PubMed1988

Fine structure of the A-band in cryo-sections. Diversity of M-band structure in chicken breast muscle.

Electron micrographs of longitudinal ultrathin cryo-sections and plastic sections of chicken pectoralis muscle together with their average images have been used to study in detail the axial structure of the M-band. It was found that M-band structure could vary markedly in different fibres, even within the white part of the muscle. Strong M-band density ("M-bridges") could be seen at M4 and M4' in all fibres. On the other hand the density at M1 or M6 could vary systematically. Some fibres (probably fast) had M1 strong, M6 weak (a "3-line" M-band), and the Z-band was narrow. Other fibres, especially (but not exclusively) in the red part of the muscle and probably slow, had M6 strong, M1 weak (a "4-line" M-band), and the Z-band was broad. However, the majority of fibres ranged in structure between those two extremes and had a more or less "5-line" M-band with M1 and M6 both strong and a Z-band of intermediate width. Since they were such a constant feature, the M4 lines may be the sites of the primarily structural component of the M-band, whereas the different proteins at M1 and M6 may vary in quantity according to the physiological needs of the fibre. Finally, detailed analysis sometimes revealed substructure within the strong M-bridge lines. This substructure may represent additional unknown M-band proteins or may be an indication of the shape of single proteins at these positions.

Animals↗
PubMed1982

Muscle structure, cryo-methods and image analysis.

Negatively stained cryo-sections from glutaraldehyde fixed, anti-freeze treated muscle, quench-frozen in Freon cooled by liquid nitrogen, show improved preservation of axial structure of the myofibrils compared with conventional plastic sections. Such sections are being used both to characterize the structural differences inthe M-bands of different vertebrate muscles and fibre types and also to define the axial distribution of myosin crossbridges and non-myosin proteins in the crossbridge region of the A-band. Combined with analysis of the transverse A-band structure from plastic sections, the cryo-sections are helping to reconstruct a three-dimensional picture of the molecular architecture of the A-band. This, in turn, is providing the necessary structural background with which to interpret the wealth of published X-ray diffraction data on muscle. Such data should reveal the nature of the contractile event itself. Since good X-ray diffraction patterns can be obtained from living muscles, these can be compared with optical diffraction patterns from muscle cryo-sections as a means of testing the degree of preservation in the sections. Muscle is therefore an excellent tissue with which to evaluate new cryo-techniques.

Animals↗
PubMed1982

Contribution of cryotechniques to the study of elastin ultrastructure.

Cryomethods were used in order to investigate the ultrastructure of native elastin fibres from beef ligamentum nuchae. Filaments of diameter 5 nm, running almost in parallel in purified, negatively-stained elastin preparations, were also seen running along the elastin fibre both in freeze-fractured and etched elastin, that had been stretched up to 200%, and in cryo-sectioned elastin that had been stretched and chemically fixed before freezing. Interconnections between elastin filaments were revealed by the freeze-etching technique. Glycerol treatment, which probably leads to hydration of specimens, resulted, however, in disorganization of filaments and swelling of the elastin fibre. In conclusion, by the use of cryotechniques, it was convincingly demonstrated that elastin molecules are arranged in long interconnecting filaments of about 4-5 nm width.

Animals↗