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Biomedical subjects

M G Williams

Publications and source records attributed to M G Williams.

At least 73 records · Page 4Linked to original sources
PubMed1981

Preparation of sphingolipid fatty acid methyl esters for determination by gas-liquid chromatography.

Sphingolipid fatty acids are first converted to a mixture of free acids and their n-butyl esters by heating the specimen at 85 degree C in aqueous butanolic hydrogen chloride; the butyl esters are then saponified with methanolic potassium hydroxide. After acidification and extraction into hexane, the fatty acids are extracted into a very small volume of aqueous trimethyl(m-trifluorotolyl)ammonium hydroxide (TMTFTH), injection of an aliquot of the TMTFTH extract into the gas chromatograph yields the fatty acid methyl esters by pyrolytic methylation of the quaternary ammonium salts of the fatty acids. The preparation of a specimen ready for the gas--liquid chromatographic (GLC) analysis with quantitative recovery of the sphingolipid fatty acids can be accomplished in less than 2 h. By comparison, none of a number of well-accepted techniques for the release of sphingomyelin fatty acids by hydrolysis or methanolysis released the fatty acids quantitatively in less than 3 h, and all required additional manipulations before GLC analysis.

Animals↗
PubMed1980

A comparison of ultrastructural characteristics of bronchoalveolar macrophages in perfused parenchyma with those obtained by a fixative or physiological saline lavage.

A comparison was made of the ultrastructural characteristics of bronchoalveolar macrophages from perfused lung parenchyma with those obtained from lavage procedures using either a balanced salt solution or buffered fixative. In comparing morphology by scanning and transmission electron microscopy, it was observed that the macrophages recovered through the fixative lavage procedure were more nearly like those found in perfused parenchyma. These characteristics included polarized surface extensions and pleomorphic forms. The cells collected via balanced salt lavage were consistently oval in shape and had randomly distributed peripheral processes. The ultrastructural features were found to be superior in the fixative lavage preparation when compared with those cells obtained in balanced salt solution.

Animals↗
PubMed1979

Morphological definition of a case of 'usual' interstitial pneumonia.

A 61-year-old Caucasian female complained of shortness of breath, fever, and a period of rapid weight loss. After routine studies, the patient underwent an open lung biopsy in order to define the characteristics of the interstitial lung disease, and initiate appropriate therapeutic intervention. Typical fibrotic and cellular proliferation were evident in the parenchyma, as determined by standard light microscopy. However, in a correlated study using light microscopy of plastic embedded tissue, as well as scanning and transmission electron microscopy, a major proliferating cell type was identified as a type II pneumocyte. These cells were the predominant lining cells of the alveoli and clearly protruded into and limited available respiratory air spaces. The predominance of type II pneumocytes in the pathogenesis of certain respiratory diseases requires that a better explanation be sought for this phenomenon.

Female↗
PubMed1978

Fine structure of reactive cells in injured nervous tissue labeled with 3H-thymidine injected before injury.

To examine the fine structure of blood mononuclear cells in injured nervous tissue, mice were given repeated injections of 3H-thymidine with the last injection at least 16 hours before injury. Under ether anesthesia the animals either were given a stab wound to the spinal cord or had their left hypoglossal nerve transected. The animals were killed at 2, 4, 8, or 16 days after injury. Tissue sections containing the spinal cord wound or both hypoglossal nuclei were prepared for electron microscopic radioautography, and all labeled cells were photographed. About half the labeled cells in the injured spinal cords and almost all the labeled cells in the nuclei of the injured hypoglossal nerves had nuclei with dark staining peripheral heterochromatin, dark cytoplasm with long cisternae of granular endoplasmic reticulum, and other ultrastructural features characteristic of the cells usually identified as microglia. The remaining labeled cells in the injured spinal cords were macrophages, fibroblasts, cells with pale nuclei, some of which contained cytoplasmic filaments, and vascular cells. Since uninjured nervous tissue has extremely few labeled cells and since 3H-thymidine should be available for only a short time following injection, most of the labeled cells in this experiment should be derived from blood mononuclear cells. However, the possibility is discussed that some or all of the labeled cells may be intrinsic cells proliferating in response to the injury and labeled through reutilization of labeled DNA precursor material.

Animals↗
PubMed1977

The use of elemental iodine to enhance staining of thin sections to be viewed in the electron microscope.

A noticeable increase in contrast is observed when thin sections, stained with Reynolds lead citrate, are subsequently exposed to elemental iodine vapor for 30 seconds. There is no loss of ultrastructural detail, and there is no evidence of harmful iodine contamination of the microscope after prolonged study of such material. It is recommended that this simple procedure be used when other methods of staining have not proved adequate.

Animals↗
PubMed1975

Distribution of microtubules in prolactin cells of lactating rats.

The intracellular distribution of microtubules was studied using serial sections of prolactin cells in anterior pituitary glands from lactating rats. Numerous microtubules were present in these cells following fixation with glutaraldehyde and osmium tetroxide. The greatest number of microtubules were present in the Golgi complex, situated around the perimeter and in association with the cisternae, vesicles and developing secretory granules. Microtubules were found in channels between groups of parallel cisternae of rough surfaced endoplasmic reticulum and in close proximity to small vesicles. They were also located adjacent to mitochondria, the plasmalemma, the nuclear envelope, and among mature secretory granules. Due to their orientation within the cell, it is suggested that the microtubules may act to direct the movement of organelles from one region of the cell to another and to give internal support to the cell.

Animals↗
PubMed1968

Further electron microscope characterization of spore appendages of Clostridium bifermentans.

Two distinct spore appendage types of Clostridium bifermentans, a pinlike appendage and a tubular appendage, were studied by electron microscopy. The pinlike appendage is characterized by a shaft, about 100 A in diameter, which has a lobed caplike structure. The tubular appendage, 500 to 600 A in diameter, is characterized by a hirsute region consisting of small filaments or fibrils. Gross morphology and ultrastructural features of both types are described.

Clostridium↗
PubMed1967

Clostridium spores with ribbon-like appendages.

Spores of Clostridium sp. N1 are characterized by numerous broad ribbon-like appendages attached to one end. The appendages are two to three times the length of the spore and, at their maximal dimension, may be two-thirds the width of the spore. They are attached to the spore body by a common trunk which is continuous with the outer spore coat. Each appendage is a multilayered structure and is enclosed in an amorphous material. Details of spore and appendage formation are described, and appendage ultrastructural features are presented. The function of the appendages is not known.

Clostridium↗
PubMed1966

Utility of sodium hypochlorite for ultrastructure study of bacterial spore integuments.

Rode, L. J. (The University of Texas, Austin), and M. Glenn Williams. Utility of sodium hypochlorite for ultrastructure study of bacterial spore integuments. J. Bacteriol. 92:1772-1778. 1966.-Spores of Bacillus megaterium are partially dissolved by sodium hypochlorite. Spore integuments become visible during the dissolution, and ultrastructural features may be detected. Three distinct integument types are described for B. megaterium QM B1551 with the use of this technique. Since a variety of microbial cells are affected by sodium hypochlorite, its use may be applicable to ultrastructure study of cells other than bacterial spores.

Bacillus megaterium↗
PubMedDate not supplied

A procedure for the isolation of amosite asbestos and ferruginous bodies from lung tissue and sputum.

A comprehensive scheme is described for isolating amosite asbestos and ferruginous bodies from fixed and unfixed human lung tissue and sputum. This qualitative procedure avoids many of the problems associated with previous isolation techniques and illustrates the advantages of brief bleach digestions. The samples are digested in prefiltered Wright laundry bleach (9.2% sodium hypochlorite), collected on 0.2-microns Nucleopore filters by vacuum filtration, rinsed with distilled water and absolute ethanol, and examined visually for excessive residue. If organic residues are suspected or are known to occur, the sample is treated sequentially with 2% potassium permanganate, 8% oxalic acid, and 9.2% sodium hypochlorite, and rinsed with distilled water and absolute ethanol. The ethanol, potassium permanganate, and oxalic acid steps can be repeated as often as needed until the desired sample volume has been filtered. The entire procedure allows large volumes to be filtered and yields filters that have extremely clean backgrounds. Filtration can be completed in as little as 15 min, as opposed to the hours or days recommended for other procedures. The technique is applicable to specimens fixed in Saccomanno's fixative or glutaraldehyde, and to those in an unfixed state. The procedure does not appear to damage the gross morphology of the amosite fibers, and it does not produce a detectable change in their elemental composition when determined by energy-dispersive X-ray analysis.

Asbestos↗
PubMedDate not supplied

Method for removing the ferruginous coating from asbestos bodies.

A new technique for removing the ferruginous coating from ferruginous bodies is described. The tissue from occupationally exposed individuals was digested in bleach and the material collected on a Nucleopore filter. The ferruginous bodies were localized by light microscopy and either cleaned on the marked filter or transferred to a marked area on a clean filter. The chemical treatment consisted of an 8% oxalic acid bath used at various temperatures. It was determined that at 75 degrees C the reaction resulted in removal of the ferruginous coat, leaving an exposed core for further analysis. This procedure overcomes the previous analytical problems of core analysis caused by the ferruginous coating.

Asbestos↗
PubMedDate not supplied

Ultrastructural and Energy dispersive analysis of inorganic inclusions in a muscle biopsy.

A muscle biopsy that, by light microscopy, exhibited mild atrophy consistent with chronic denervating disease was submitted for ultrastructural analysis. Inorganic structures within the tissue were defined by energy dispersive analysis as aluminosilicates, magnesium silicates, and iron deposits. These structures were localized in the interstitial (intercollagenous) area and in high concentrations within degenerated muscle bundles. An alteration of the blood/muscle barrier has obviously occurred; however, the extent to which the end result commonly occurs in humans is unknown. Clarification of the question raised by this observation will have to be derived from animal studies, and clinicians must have an awareness of the need for electron microscopy/energy-dispersive x-ray analysis in muscle biopsies from patients with similar therapeutic backgrounds.

Atrophy↗