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F H Bilge

Publications and source records attributed to F H Bilge.

6 recordsLinked to original sources
PubMed1993

Determination of the role of cuticular carbohydrates in the hemocompatibility of Dirofilaria immitis (Nematoda).

We have partially characterized surface glycoproteins of the canine heartworm, Dirofilaria immitis. Histochemical studies indicated the presence of neutral and acidic mucopolysaccharides at the blood-cuticle interface. Fluorescein isothiocyanate-conjugated lectin binding patterns suggested the presence of alpha-D-glucosyl and/or alpha-D-mannosyl, beta-galactosyl, N-acetylneuraminyl and N-acetylated-D-hexosaminyl (sialic and glucuronic acids, respectively) terminal residues among the constituent sugars of the glycocalyx. An additional goal of this study was to assess the significance of each carbohydrate in parasite hemocompatibility by using scanning electron microscopy, internal reflection infrared spectroscopy, and comprehensive contact angle measurements. Each carbohydrate identified in the glycocalyx was selectively cleaved with the appropriate exoglycosidase. Heart-worms bearing native and enzyme-altered surfaces were exposed to platelet-rich canine plasma. Activation and aggregation of platelets were significantly increased on enzyme-treated surfaces as compared with native surfaces. Enzyme-induced cleavage of carbohydrate residues was associated with an increase in critical surface tension or a loss in cuticular structural integrity or both. Hemocompatibility of the heartworm cuticle depends on the retention of a stable saccharide-rich layer that minimizes interaction with plasma proteins and platelets; thus, carbohydrate residues on the glycocalyx may contribute to parasite hemocompatibility. The presence of similar low-critical-surface-tension coatings with high mechanical integrity may impart thromboresistance to other polyphenolic or chitinous substances.

Alcian Blue↗
PubMed1989

Surface characterization of the cuticle of Dirofilaria immitis.

The surface reactivity of the dog heartworm (D. immitis) was evaluated by comprehensive contact angle measurements and a platelet retention test. Contact angle data yielded calculated surface energy terms very similar to those previously reported for intact vascular endothelium. The platelet test revealed the native worm surface to be nonreactive, retaining fewer platelets than glass or worms whose surfaces had been modified by extraction with acid and high salt solutions. The cuticular morphology of the heartworm was studied with both light and electron microscopy, the latter coupled with ferritin-conjugated double-layer immunolabeling to reveal adsorbed host protein on the cuticle surfaces. Multiple attenuated internal reflection (MAIR) IR spectroscopy confirmed the general composition of this surface layer to be glycoproteinaceous. Morphological and histochemical studies confirmed and extended previous descriptions of nematode cuticle, adding ultrastructural detail on cortical, medial, and basal layers. A trilaminar membrane, apparently corresponding to a mammalian cell membrane (plasmalemma), constituted the external cortical layer as observed in high magnifications. The existence of a glycocalyx of varying thickness was demonstrated in ruthenium red-stained sections. MAIR IR spectra showed this glycoproteinaceous film to appear, in fully hydrated samples, as a loose biological gel. Ferritin-antibody conjugate labeling confirmed the presence of adsorbed dog albumin, dog immunoglobulin class G (IgG) and dog complement fraction 3 (C3) in the cuticular surface layer. It is likely, therefore, that D. immitis heartworms demonstrate long-term thromboresistance at least in part due to their passive low-surface-energy overcoating with host proteins.

Animals↗
PubMed1989

Partial characterization of the adsorbed protein layer on Dirofilaria immitis (Nematoda) cuticle.

Electron microscopy coupled with ferritin-conjugated indirect immunolabeling was used to locate sites of adsorbed host protein on cuticular surfaces of the adult canine heartworm, Dirofilaria immitis. The epicuticle appeared as a trilaminated structure. At high magnifications, the outermost layer of this structure was resolved into a trilaminar layer, which might correspond to the plasma membrane of animal cells. A ruthenium red-positive layer was external to the epicuticle. Ferritin-antibody conjugates showed evidence of adsorbed dog albumin, dog immunoglobulin class G (IgG), and dog complement fraction 3 (C3) on the surface. Ferritin adsorption to control surfaces was minimal. Possible causes and effects of interfacial host-protein adsorption are discussed in an attempt to bring insight to the hemocompatible nature of the parasitic cuticle.

Animals↗
PubMed1980

Effects of fluid shear and temperature on protein adsorption on teflon surfaces.

Partial gold decoration TEM images of protein adsorption on Teflon have been reliably obtained and confirmed by independent imaging methods. Albumin deposits are irregular in shape, unconnected, with low surface coverage in the range of 25-2500 mg/dl. The deposits tend to follow surface structural details to a scale of 4000A. In contrast, Cohn I fibrinogen deposits are reticulated, connected, with high surface coverage, which do not reflect details of surface structure, in the range of 3-300 mg/dl. The albumin adsorbates decrease with increasing wall shear rate and have negligible temperature dependence. The Cohn I fibrinogen adsorbates are not shear dependent, up to 800 sec-1, nor are they temperature dependent from 20-40 degrees C. These results support the view that nondenatured albumin maintains weak protein-polymer and protein-protein bonds, whereas Cohn I fibrinogen adsorbates are fostered by strong protein-protein interactions.

Adsorption↗
PubMedDate not supplied

Peritoneal oxygenation of normoxic and hypoxic dogs.

The ability of an oxygen saturated fluorocarbon, perfluorodecalin (C10F18), to raise the arterial partial pressure of oxygen (PaO2) of anesthetized dogs, was tested by peritoneal lavage in normoxic and hypoxic animals. While breathing room air, five of six animals showed an increased PaO2 of 5-10 torr above reference values. In cases of mild hypoxia, increases of 5-25 torr were observed. No increase in PaO2 was seen when hypoxia was severe. A mathematical model was used to analyze the data and determine a transport coefficient (k). Calculated k values were 1.18 +/- 0.151 ml O2 STPD per minute for normoxic animals and 0.91 +/- 0.180 ml O2 STPD per minute for hypoxic animals, respectively. The estimated transport coefficients are small and indicate that physiologically significant amounts of O2 cannot be delivered by the proposed method under the experimental conditions used. The low k values were attributed to long diffusion distances and small effective surface areas in the abdominal cavity.

Animals↗