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Biomedical subjects

R F Dodson

Publications and source records attributed to R F Dodson.

At least 91 records · Page 5Linked to original sources
PubMed1975

Morphological responses of cerebral tissues to temporary ischemia.

The ultrastructural responses of cerebral tissue following temporary periods (1/2, 1,2,3, or 4 hour) of right, middle cerebral artery, (MCA) occlusion were studied acutely after a 3 day or 7 day interval following the removal of the MCA clip. Cortical and basal ganglia tissues for each ischemic duration were compared at 3 post-occlusive periods (acute, 3 days, 7 days). With the short periods of ischemic insult (1/2, 1, 2, 3, and 4 hour), the temporal and insular cortex contained no greater changes in the 7 day group than in the 3 day group. The basal ganglia were more susceptible to MCA occlusion as indicated by more marked cytological changes and/or necrosis in all intervals of ischemia.

Acute Disease↗
PubMed1975

Multilating granuloma inguinale.

Granuloma inguinale is an uncommon infectious granulomatous disease of the inguinale area that can insidiously engulf and mutilate tissue. The reported case of granuloma inguinale demonstrated the painless progression of the disease to destroy most penile, scrotal, and inguinal tissue and also showed the subsequent satisfactory therapeutic result with antibiotic treatment. Light microscopy of plastic-embedded thin-sectioned tissue specimens allowed clear demonstration of the Donovan bodies and may be valuable in diagnosis.

Granuloma Inguinale↗
PubMedDate not supplied

An individual with a majority of ferruginous bodies formed on chrysotile cores.

A 59-year-old man was exposed to chrysotile asbestos while rebuilding clutches. Analytical electron microscopy showed a chrysotile core in 72% of the ferruginous bodies from lung tissue. Long, uncoated chrysotile fibers were also present. Sufficient exposure to long chrysotile in jobs such as this appears to allow the majority of ferruginous bodies to be formed on chrysotile, an exception to the rule that most ferruginous bodies form on amphibole cores.

Asbestos, Serpentine↗
PubMedDate not supplied

Relationships between ferruginous bodies and uncoated asbestos fibers in lung tissue.

Tissue was obtained from two American groups. The tissue was defined by ferruginous body levels of either < or = 1000 or > 1000 ferruginous bodies/g dry weight, and tissue was evaluated by light microscopy and analyzed by analytical transmission electron microscopy. Tissue was bleach digested, and uncoated asbestos fibers were classified with respect to type and size. In addition, some ferruginous body cores were analyzed. There was a wide range of uncoated fibers associated with each ferruginous body. A relationship was found between amosite fibers and ferruginous bodies. Other asbestos types were not associated significantly with the development of ferruginous bodies. Uncoated crocidolite fibers were not detected in these samples; this result further emphasizes the under-appreciated exposure of Americans to amosite. The levels of ferruginous bodies in both groups suggest exposures above those expected in the general population. Uncoated chrysotile levels were below the ranges reported previously for some general populations. The data suggest that there is a wide variation in the ratio of uncoated to coated fibers and that the amphibole in the United States is more likely to be amosite than crocidolite.

Aged↗
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

Regional cerebral blood flow measured by the gamma camera after direct injection of 133Xe into the distal stump of the occluded middle cerebral artery.

Regional cerebral blood flow (rCBF) was measured after intracarotid injection of 133Xe concurrently with measurements of local cerebral blood flow (LCBF) after injection of 133Xe directly into the distal stump of the occluded middle cerebral artery (MCA) by the use of the gamma camera after producing experimental ischemia in baboons by occluding the MCA. Regional MCA stump pressure (rMCAP) was also measured. Regions of ischemia assessed by intracarotid injection of 133Xe correlated well with the territory of infarct defined by injection of 133Xe into the distal MCA stump. Flow values in ischemic regions obtained by direct injection of 133Xe into the MCA were 15% to 20% lower than those obtained by intracarotid injection of 133Xe. Possible explanations for these differences are discussed. During induced hypertension autoregulation in ischemic areas was abolished and paradoxical responses of LCBF and rMCAP to changes in arterial carbon dioxide tension (PaCO2) were confirmed.

Animals↗
PubMedDate not supplied

An ultrastructural assessment of an embolic method of producing cerebral ischemia.

This study presents ultrastructural confirmation of the embolic method of producing an ischemic lesion. The embolic method was shown to produce more advanced parenchymal changes than those reported for the same postocclusion period following vascular clipping. With this method there was less alteration in the morphological intergrity of occluded extraparenchymatous areas of the arterial bed, especially in the associated nerve bundles.

Animals↗
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↗