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Biomedical subjects

T L Hayes

Publications and source records attributed to T L Hayes.

At least 37 records · Page 2Linked to original sources
PubMed1984

Etched surfaces of plastic embedded and frozen hydrated gastrointestinal tissue.

Scanning electron microscopy (SEM) is most often used to describe the structure of natural surfaces, but it can also be used to examine surfaces created artificially by sectioning or cryofracture. When plasma etched resin sections are studied, the SEM combines some of the functions of a light microscope and a transmission electron microscope. When etched frozen hydrated tissue is examined the groundwork is laid for the use of X-ray microanalysis for the study of elemental concentrations in tissue unexposed to chemical agents of any kind. Examples are given of the study of jejunum and stomach with these two techniques. The results are integrated with data from conventional SEM images to produce composite diagrams which assist with the interpretation of function and topographical morphology.

Animals↗
PubMed1983

Cold-stage scanning electron microscope measurement of ice morphology in apple tissue as a function of freezing rate.

A cold-stage SEM was used to document the morphology of ice in apple tissue and a sucrose solution frozen at rates ranging from 450 to 0.03 degrees K/min. Freezing rates of 3-mm-thick apple discs were measured with a differential thermocouple technique, which gave measurement of the growth velocity and the temperature gradient through the solidified specimen as well as the cooling rate during solidification. Cold-stage SEM micrographs were used to measure the dendritic spacing of the ice structures, and these data were found to correlate linearly with the square root of the cooling rate during solidification as would be predicted by a theoretical analysis of mass transfer in the formation of dendrites. Comparison of freeze-substituted and freeze-dried apple-tissue micrographs with those from a cold-stage SEM showed that the cold-stage SEM technique was the only one which correctly represented ice morphology in apple tissue.

Food Preservation↗
PubMed1983

Low temperature scanning electron microscope studies of mouse small intestine.

Etched frozen hydrated specimens of mouse small intestine have been examined with low temperature scanning electron microscopy as a preliminary to X-ray microanalysis. Recognizable images have been obtained of most of the known histological features of the gut. Nuclear and cytoplasmic details were often seen. Ice crystal damage was evident, although the degree of artefact depended on the cell type being examined and also varied from cell to cell or within cells. The same specimens were later examined with resin light microscopy and transmission electron microscopy. These two techniques confirmed that preservation was adequate for identification of cells and tissues, although cavities were seen, representing ice crystal damage. These preliminary results indicate that SEM of etched, frozen, hydrated specimens provides adequate identification of cellular detail to allow further work using X-ray microanalysis to be carried out.

Animals↗
PubMed1983

Lung structure as revealed by microdissection. Positional morphology of human lung.

A technique of lung structure analysis is presented that allows visualization of the airway in its conceptual form. The lung is dissected such that the bronchial tree appears as a branching, continuous surface whose fine structure varies as a function of position along the airway. In these preparations, single loci of interest can be studied sequentially with any optical or electron microscope. This provides precise correlation of surface morphology and intracellular structure. Microstructural information can be indexed by either branch order or linear distance along the air path. Morphometry can be performed on surface features of the airway imaged with the scanning electron microscope using this indexing system. The anatomy of a human airway is presented.

Aged↗
PubMed1982

Surface morphology and functional studies of human alveolar macrophages from cigarette smokers and nonsmokers.

The surface of macrophages inhabiting the peritoneal and alveolar spaces is pleomorphic in structure. The internal structure of these cells has been widely described and is not discussed here. Although external cell morphology has been well characterized by many researchers, this subject has not been reviewed. This review, therefore, describes in detail the surface features of macrophages as well as factors affecting macrophage morphology. Morphological studies of human cells are emphasized. Functional studies are presented and, when possible, morphological parameters are correlated with cell function. Because cigarette smoking has been well studied, the effects of this pulmonary insult are described in detail.

Anesthetics, Local↗
PubMed1981

Some indications of structural damage in retina by heavy ion radiation.

At the Lawrence Berkeley Laboratory Bevalac Facility, iron nuclei were accelerated to an energy of 600 MeV/amu. The beam of iron thus obtained was used to irradiate living biological specimens in order to study possible microscopic tissue damage with the aid of SEM. The experiments involved total head irradiation of live rats which were subsequently returned to their cages to remain for 1 day and 30 days before further examination. After the 1 day and 30 day waits, both eyes were enucleated and placed in chemical fixative followed by ethanol dehydration and critical point drying. Retinas were carefully removed from the eye cups and loaded separately on aluminum stubs which were sputter coated. SEM of the 1 day and 30 day retinas revealed lesions which were not found at all in control retinas. The 1 day and 30 day retinas manifest regions where outer rod segments were missing or rearranged. A single energetic iron nucleus may be capable of generating a retinal lesion which becomes enlarged as biological processes intervene during the 1 day and 30 day waits. Being composed of highly specialized nerve cells, retinas cannot regenerate following irradiation which severely damages the rod cells. Thus one would expect the observed radiation induced retinal lesions to correspond to permanent tissue damage and possible loss of visual acuity in the intact animal.

Animals↗
PubMed1980

Endogenous and exogenous ocular and systemic silver deposition.

The ocular distribution of particulate silver after prolonged ingestion and the topical application of an organic silver compound (argyrol) are described and compared with the distribution after long-term occupational contact with refined silver. The deposits appear to be inert and to cause no functional visual deficit.

Aged↗
PubMed1980

Morphological studies of cultured human pulmonary macrophages.

A morphological classification scheme is developed for the quantitative in vitro examination, by scanning electron microscopy (SEM), of pulmonary alveolar macrophages (AM) from human cigarette smokers and nonsmokers. The AM were obtained by bronchopulmonary lavage, allowed to attach to glass coverslips in a serum containing medium, cultured for 1, 2, or 25 hours, and examined in the SEM. Fifty cells per sample were randomly selected for detailed morphological analysis using a predetermined sampling grid. Area, form, degree of cell spreading, and the relative abundances of surface features, including ruffles, filopodia, blebs, microvilli, multiple features, and no surface features were quantified. Smoker AM had a greater incidence of ruffles, filopodia, multiple features, and rounded cells; nonsmoker AM had greater incidences of featureless and spread cells. Microvilli and blebs were observed infrequently and displayed no trends with respect to differences between smokers and nonsmokers. The incidence of filopodia, multiple features, and intermediate shapes generally increased with increasing culture time, and a decreasing incidence with increasing time in culture was observed for featureless and spread cells. For the 1- and 2-hour culture periods, slightly greater sizes, size variances, form factors, and form factor variances were observed for smoker AM; however, after 25 hours in culture, nonsmoker AM populations possessed these characteristics. Area frequency distributions appeared to be logarithmically normal in distribution. Statistical analyses indicated that for area and form, the greatest variance was due to variations among the individuals lavaged.

Cell Adhesion↗
PubMed1977

Survival of cultured mammalian cells exposed to ultrasound.

The colony-forming ability of cultured mammalian cells exposed to monochromatic ultrasonic vibrations of different frequencies (0.1, 0.5, 1.0, 2.0, 3.3 MHz) was studied. The combined effect of x rays and 1.0-MHz ultrasonic waves on the survival of M3-1 cells was also investigated. Split-dose experiments showed that cells exposed to ultrasound are "sensitized" to a subsequent exposure. Almost twice as many cells survive a given ultrasonic dose when exposed in the M phase as when exposed in the S phase. A small amount of synergism between ultrasound and x rays has been observed. The extent of synergism depends on the experimental factors, and may be due to an interaction between nuclear damage caused by x rays and the damage to the cell membrane caused by ultrasound.

Cell Survival↗
PubMed1976

A clinical pathologic study of mercurialentis medicamentosus.

Thirty-one patients who used eye drops containing the preservative, phenylmercuric nitrate for from 3 to 15 years, developed a brownish pigmentation of the anterior capsule of the pupillary area. Light and electron microscopic studies on two lenses demonstrated deposits of dense particulate material resembling melanin pigment on and in the anterior capsule of the lens in the area of the pupil. Special studies, including electron microprobe analysis and neutron activation analysis established the presence of mercury in a lens with mercurialentis. No mercury was found in two lenses used as controls.

Adult↗