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Biomedical subjects

G F Odland

Publications and source records attributed to G F Odland.

At least 19 recordsLinked to original sources
PubMed1990

Correlation of tissue constituents with the acoustic properties of skin and wound.

The purpose of this study was to compare measurements of ultrasound properties of skin and wound tissue with measurements of material properties such as total collagen concentration, acetic acid soluble collagen concentration, water concentration, and morphologic properties. Using a scanning laser acoustic microscope (SLAM), both ultrasonic speed and attenuation coefficient values were obtained for control skin (2-3 cm from the wound), for skin immediately adjacent to wounds (within 0.3 mm), as well as for wound tissue itself. The attenuation coefficient and speed measurements were lowest for wound tissue followed by adjacent skin and then control skin. As the wounds healed there appeared to be an increase in both speed and attenuation coefficient although the wound age at which these increases started and the length of time for which they continued varied from one dog to the next. The precision of duplicate sample measurement of wave speed was +/- 1.7% for control skin, whereas that for attenuation coefficient it was +/- 16%. Both ultrasonic speed and attenuation coefficient were directly correlated with tissue collagen concentration and inversely correlated with tissue water concentration (p less than 0.001). Attenuation coefficient correlated best (r = 0.73) with acetic acid soluble collagen concentration which reflects the changes in collagen taking place during the repair process. These attenuation measurements made at 100 MHz using the SLAM were compared for control skin and wound samples with measurements made at 10-40 MHz using backscatter acoustic techniques (BAT). The tissue samples analyzed by each ultrasound technique were from adjacent locations on the animals.

Acoustics↗
PubMed1990

Temporal relationships of F-actin bundle formation, collagen and fibronectin matrix assembly, and fibronectin receptor expression to wound contraction.

Wound contraction can substantially reduce the amount of new tissue needed to reestablish organ integrity after tissue loss. Fibroblasts, rich in F-actin bundles, generate the force of wound contraction. Fibronectin-containing microfibrils link fibroblasts to each other and to collagen bundles and thereby provide transduction cables across the wound for contraction. The temporal relationships of F-actin bundle formation, collagen and fibronectin matrix assembly, and fibronectin receptor expression to wound contraction have not been determined. To establish these relationships, we used a cutaneous gaping wound model in outbred Yorkshire pigs. Granulation tissue filled approximately 80% of the wound space by day 5 after injury while wound contraction was first apparent at day 10. Neither actin bundles nor fibronectin receptors were observed in 5-d wound fibroblasts. Although fibronectin fibrils were assembled on the surfaces of 5-d fibroblasts, few fibrils coursed between cells. Day-7 fibroblasts stained strongly for nonmuscle-type F-actin bundles consistent with a contractile fibroblast phenotype. These cells expressed fibronectin receptors, were embedded in a fibronectin matrix that appeared to connect fibroblasts to the matrix and to each other, and were coaligned across the wound. Transmission EM confirmed the presence of microfilament bundles, cell-cell and cell-matrix linkages at day 7. Fibroblast coalignment, matrix interconnections, and actin bundles became more pronounced at days 10 and 14 coinciding with tissue contraction. These findings demonstrate that granulation tissue formation, F-actin bundle and fibronectin receptor expression in wound fibroblasts, and fibroblast-matrix linkage precede wound contraction.

Actins↗
PubMed1989

The hamster flank organ model: is it relevant to man?

The critical role that androgens play in the etiology of acne has led to a search for topically active antiandrogens and the frequent use of the flank organ of the golden Syrian hamster as an animal model. 17-alpha-propyltestosterone (17-PT) has been identified as having potent antiandrogenic activity in the hamster model, and this report describes its clinical evaluation. Two double-blind placebo controlled studies comparing 4% 17-PT in 80% alcohol versus vehicle alone were conducted. One study examined 17-PT sebosuppressive activity in 20 subjects. The second study examined its efficacy in 44 subjects having mild to moderate acne. A third study measured in vitro percutaneous absorption of 17-PT through hamster flank and monkey skin, and human face skin in-vivo, using radioactive drug. 17-PT was found to be ineffective in reducing either the sebum excretion rate or the number of inflammatory acne lesions. Failure of 17-PT to show clinical activity was not a result of poor percutaneous absorption. Total absorption in man was 7.7% of the dose and only 1.0% in the hamster. The sebaceous gland of hamster flank organ is apparently more sensitive to antiandrogens than the human sebaceous gland.

Acne Vulgaris↗
PubMed1989

A method for localizing the early products of nonenzymatic glycosylation in fixed tissue.

The process of nonenzymatic glycosylation (NEG) may play a significant role in the development of chronic complications of diabetes. Early products of NEG can be measured by various biochemical methods. A method has been developed to localize these early products of glycosylation in vivo in fixed tissue sections of normal and diabetic skin using monoclonal antibodies specific for glucitollysine, which is formed when the early products of NEG are chemically reduced in vitro. Carnoy's-fixed, paraffin-embedded skin samples from six diabetic and 13 nondiabetic subjects were sectioned, mounted on glass slides, and reduced for one h in 100 mM NaBH4. Immunolocalization was by the avidin--biotin immunoperoxidase method. Diabetic skin consistently stained more intensely for glucitollysine than nondiabetic skin. Staining around vessels, in particular, and of the collagenous matrix in general, was markedly enhanced in diabetic skin compared with nondiabetic skin. Antigens present in both the epidermis and the eccrine structures reacted with the antibody in both diabetic and nondiabetic skin but with greater intensity in the diabetic skin. This study has shown that it is possible to localize the early products of NEG in tissue sections using monoclonal antibodies. The findings correlate with biochemical data that show increased NEG in diabetics compared with nondiabetics. This technique should prove valuable for further investigations of the role of NEG in the pathogenesis of diabetes.

Aged↗
PubMed1988

An assessment of human epidermal repair in elderly normal subjects using immunohistochemical methods.

The purpose of this study was to document a timetable for selected events of epidermal repair in standard partial thickness incised wounds on the legs of normal elderly human subjects. A Simplate-II bleeding-time device was used for producing the wounds, and immunohistochemical techniques were employed for evaluation of the wounds. Antibodies to filaggrin and Ulex europeus I demonstrated little or no staining on migrating epithelium, but staining was apparent whenever epidermal closure had occurred. Bullous pemphigoid antigen was present in the basement membrane zone at all time points examined, including beneath migrating epithelium, whereas antibodies to laminin and type IV collagen were found only at the most lateral aspects of 2-, 3-, and 5-day wounds. Staining progressed centrally by day 7 and was present as a complete linear band beneath most 14-day wounds. The Simplate-II device provides a standard, easy to use, commercially available, sterile, relatively safe method of producing wounds for systematic studies in humans.

Aged↗
PubMed1987

Ultrasonic assessment of skin and wounds with the scanning laser acoustic microscope.

The aim of the present study was to test the hypothesis that ultrasonic propagation properties in skin and wound tissue would correlate with material properties such as collagen content, water content, and tensile strength of those tissues. Both ultrasonic speed and ultrasonic attenuation coefficient were directly correlated with tissue collagen content, [r = 0.80 and r = 0.56, respectively (p less than 0.001)]. In addition, ultrasonic speed and attenuation coefficient were inversely correlated with tissue water content, [r = -0.57 and r = -0.73, respectively (p less than 0.001)]. Tensile strength also correlated very significantly with ultrasonic speed (r = 0.90, p less than 0.001), and significantly with attenuation coefficient (r = 0.58, p less than 0.001). The results demonstrate the feasibility of using ultrasound for noninvasively determining the material properties of biologic tissues including healing cutaneous wounds.

Animals↗
PubMed1985

Erythema gyratum repens unassociated with internal malignancy.

A case report of erythema gyratum repens occurring in a 68-year-old man is presented. Evaluation and follow-up for development of malignancy over a 39-month period failed to reveal evidence of malignancy. The patient died of an unrelated cause. Autopsy did not demonstrate any evidence of malignancy.

Aged↗
PubMed1979

Age-related changes in the mechanical properties of human skin.

The mechanical properties of skin have been studied both in vivo and in vitro by a variety of test methods. These properties are well matched to the function of the skin, and they depend on the geometry of the collagen and elastin networks of the dermis. The time dependence of these properties is thought to be related to the "ground substance" components of the dermis. Age-related changes in the mechanical properties are a function of the degradation of the elastin network and of some as yet undefined changes in the viscoelastic properties of the "ground substance."

Adult↗
PubMed1978

A collagen and elastic network in the wing of the bat.

Bundles of collagen fibrils, elastic fibres and fibroblasts are organized into a network that lies in the plane of a large portion of the bat wing. By ultrastructural (TEM and SEM) and biochemical analyses it was found that individual bundles of the net are similar to elastic ligaments. Although elastic fibres predominate, they are integrated and aligned in parallel with small bundles of collagen. A reticulum of fibroblasts, joined by focal junctions, forms a cellular framework throughout each bundle. Because of the unique features of the fibre bundles of the bat's wing, in particular their accessibility, and the parallel alignment of the collagen fibrils and elastic fibres in each easily isolatable fibre bundle, they should prove a most valuable model for connective tissue studies, particularly for the study of collagen-elastin interactions.

Amino Acids↗
PubMed1975

The fine structure of developing human epidermis: light, scanning, and transmission electron microscopy of the periderm.

Eight stages in the development of the human embryonic and fetal periderm have been established, primarily on the basis of surface morphology, major changes in epidermal stratification, and differentiation. The changes in the periderm observed with the scanning electron microscope have been correlated with and supplemented by cytologic studies with the transmission electron microscope in the periderm and other epidermal layers. Light microscopy was used to determine what proportion of the epidermal thickness is accounted for by the periderm and what relationship individual periderm cells have with underlying cells. The results yield a comprehensive, three-dimensional image of the human epidermis during development and support a concept of the periderm as a layer of "dynamic" cells which project superficial blebs, expand in surface area, then regress at the onset of keratinization, leaving only cellular remnants associated with the adult type epidermis.

Basement Membrane↗
PubMed1975

Intraendothelial tubular aggregates in experimental wounds.

Intraendothelial tubular aggregates were found in small dermal blood vessels in three healing superficial wounds in patients receiving systemic corticosteroids. Similar inclusions were also demonstrated in two wounds in healthy subjects, but were not found in normal (unwounded) skin of either healthy subjects or steroid-treated patients. Tubular aggregates of similar structure have previously been described as occurring in 'connective tissue' or 'auto-immune' diseases, including lupus erythematosus and dermatomyositis, both in the skin and in internal organs. Although it has been suggested that such aggregates are of viral origin, their morphogenesis and significance remain undertermined. Our findings do not support a viral cause, but suggest that these structures are probably a product of regenerating endothelium.

Adult↗
PubMed1975

Light and electron microscopic studies on human temporal arteries with special reference to alterations related to senescence, atherosclerosis and giant cell arteritis.

Temporal artery biopsy specimens from 26 patients of various ages with and without giant cell arteritis afforded an opportunity to examine several ultrastructural features of these human muscular arteries, including senescent and atherosclerotic alterations and the fine structural pathology of temporal arteritis. The unusual pathologic features of temporal arteritis were found superimposed on the progressive accumulation of smooth muscle cells, collagen and occasional discrete intimal atherosclerotic plaques in the intima of aging arteries. Two features of giant cell arteritis were conspicuous: first, the accumulation of large numbers of histiocytes and epitheloid and giant cells at the intimal-medial junction and second, fragmentation, degeneration and dissolution of the internal elastic lamina. The close proximity of the granulomatous reaction to the degenerating lamina suggests that these two aspects of the pathologic picture are in some way related, and possible immunologic mechanisms of this relationship are discussed on the basis of the ultrastructural findings.

Aged↗