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Biomedical subjects

E Reale

Publications and source records attributed to E Reale.

At least 73 records · Page 4Linked to original sources
PubMed1985

The elasmobranch kidney. I. Gross anatomy and general distribution of the nephrons.

The morphology of the little skate (Raja erinacea) and spiny dogfish shark (Squalus acanthias) nephron has been investigated in sexually mature females by 1) gross observations of the kidney surfaces, 2) vascular injections, 3) scanning electron microscopy, 4) light microscopy. In the little skate, each nephron is highly complex and begins at the urinary pole of the renal corpuscle, which is located between a thin, dorsal bundle zone and a thicker, ventral sinus zone. The nephron loops back and forth, repeatedly entering and exiting each zone. In the bundle zone, segments from each nephron form a bundle of 5 tubules (tubular bundle) which are arranged in a countercurrent loop fashion. A peritubular sheath composed of closely packed, squamous cells wraps the 5 nephron segments of the tubular bundle together and separates each bundle from the next. In the sinus zone the tubules from many nephrons mix freely with each other in large blood sinuses. In the spiny dogfish, the nephron displays a complex pattern similar to that of the skate. Renal corpuscles are adjacent to a bundle zone composed of tubular bundles, each wrapped by a peritubular sheath in a cell-rich connective tissue matrix. However, the bundle zone is not limited to the dorsal region of the shark kidney but extends ventrally along deep interlobular septa. The sinus zone of the shark is like that of the skate except that it is not limited to the ventral regions of the kidney.

Animals↗
PubMed1985

Filipin-cholesterol complexes (FCC) in the goblet cell granule membrane of the distal colon are arranged in a rhombic pattern.

After fixation in the presence of filipin, the membrane of the goblet cell granules of the distal colonic mucosa (guinea pig) displays, in freeze-fracture replicas, a rhombic pattern composed of intersecting "lines" of unknown nature. The filipin-cholesterol complexes of the granule membrane are ordered according to the same geometry. This arrangement--but not the "lines"--has been found for the filipin-cholesterol complexes of other membranes of the same goblet cells as well as of other colonic cells. These observations indicate that in some biological membranes cholesterol has an ordered distribution, comparable to that suggested by investigations on artificial membranes.

Animals↗
PubMed1984

Structure of zonulae occludentes and the permeability of the epithelium to short-chain fatty acids in the proximal and the distal colon of guinea pig.

Absorption of short-chain fatty acids has been studied in the proximal and the distal colon of anaesthetized guinea pigs. Segments were perfused with a solution similar in chemical composition to that of normal colonic fluids. In the proximal colon the permeability of the mucosa was similar for acetate, propionate and butyrate. For acetate the permeability was significantly higher in the proximal than in the distal colon, and the reverse was seen for butyrate. In the distal colon the short-chain fatty acids seem to be absorbed mainly in the undissociated form due to their lipid solubility; a paracellular pathway for the dissociated molecules is of no major importance. In the proximal colon, on the other hand, a considerable portion of acetate and propionate disappears in the ionized form. Light microscopy (semithin sections) and electron microscopy (freeze-fracture replicas) showed remarkable morphological differences between the proximal and the distal colon. "Leaky spots" with only few strands were present in the zonulae occludentes between the epithelial cells at the surface of the proximal colon. In the distal colon the junctions between the cells were more compact, and significantly more strands separated the lumen from the intercellular space. These results suggest that short-chain fatty acids could be absorbed by a paracellular pathway in the proximal colon, and not in the distal colon. In the proximal colon the number of strands of the zonulae occludentes between surface cells and that between cryptal cells was similar. On the contrary, in the distal colon significantly more strands were present between surface cells than between cryptal cells. Morphological and physiological considerations suggest that absorption of short-chain fatty acids in the crypts is negligible.

Animals↗
PubMed1983

Light microscopy, electron microscopy, and X-ray diffraction analysis of glycerinated collagen fibers.

Light microscopy, transmission electron microscopy (freeze-fracture replicas and thin sections), and X-ray diffraction techniques were used to investigate the structure of rat tail tendon collagen fibers subjected to one of the following treatments: water, phosphate buffer, glutaraldehyde, glutaraldehyde followed by glycerol, glycerol, and glycerol followed by phosphate buffer. As seen by light microscopy, only treatment with glycerol induces a remarkable swelling of the native (untreated) collagen specimens. Replicas and thin sections show that this swelling is due to an expansion of the interfibrillar space, and to a dissociation of the collagen fibrils into microfibrils. X-Ray diffraction analysis reveals great disorder in the glycerol-swollen collagen fibers. However, this does not appreciably involve the microfibrillar and molecular structure. Light and electron microscopy as well as X-ray diffraction techniques show that the collagen fiber swelling induced by glycerol is an almost completely reversible process.

Animals↗
PubMed1983

Ultrastructural architecture of proteoglycans in the glomerular basement membrane. A cytochemical approach.

Rat kidneys were perfused with fixative solutions containing either a) a polycationic dye (Alcian blue 8 GX, Astra blue 6 GLL, cuprolinic blue, ruthenium red), b) a monocationic dye (safranine 0), or c) Alcian blue in the presence of a 0.3 M MgCl2 concentration. Whereas solutions of a revealed the glomerular basement membrane proteoglycans as particles or threads 60 nm apart and arranged in a reticular pattern, solutions of b and c demonstrated new morphological aspects of these molecules. They appeared as tiny filamentous structures, about 100 to 160 nm long, ordered in a network-like pattern with a mesh of about 60-nm width. The filaments displayed lateral branches about 20 nm apart and about 25 nm long, projecting within the meshes. We suggest that the filamentous structures are the protein core, and the branches are the glycosaminoglycans of proteoglycan molecules. Because of this arrangement the negatively charged sites of the glomerular basement membrane would lie closer to each other than previously assumed.

Animals↗
PubMed1981

The brush cells of the common bile duct of the rat. This section, freeze-fracture and scanning electron microscopy.

Two different fixative procedures (immersion and perfusion) and four different fixative solutions were used in order to obtain the best preservation of the brush cells of the common bile duct of the rat. The results indicate that only perfusion fixation through the common bile duct is suitable, independent of the fixative solutions and their osmolarity. Numerous brush cells were seen in the proximal and distal regions of the common bile duct. In these locations, they could be implicated in a registration and/or regulation of intraluminal pressure variations.

Animals↗
PubMed1981

The basement membrane complex of the human corneal epithelium.

The present report reviews the fine structure of the basement membrane zone or complex in the normal human cornea and describes its alterations in cases of early and acute keratoconus. In normal human cornea the basement membrane zone is formed by a basal lamina (with a lamina lucida and a lamina densa), "special fibrils", collagen fibrils and assemblies of filaments. These components are less evident in the central region of the cornea than in its periphery. In early stages of keratoconus the basement membrane zone is thickened and the lamina densa displays an irregular course. In acute keratoconus, the basement membrane zone is also thickened and includes a large number of "special fibrils" as well as bundles of "microfibrils" (oxytalan fibers). The conclusion that the basement membrane complex of the corneal epithelium is equivalent to the epidermal-dermal junction of the skin is discussed.

Adult↗
PubMed1981

Occluding junctions surrounding cystoid spaces in the human peripheral retina. A thin-section and freeze-fracture study.

Transmission electron microscopic examination of thin sections and freeze-fracture replicas of areas neighboring cystoid spaces in the peripheral human retina reveals extensive networks of occluding junctions on all sides of these spaces. These junctions may be responsible for the fact that, in spite of the absence of an epithelial lining, fluid from the spaces of cystoid degeneration and retinoschisis does not leak into the surrounding retina, which would lead to their collapse.

Extracellular Space↗
PubMed1981

Overcontraction and excess actin filaments. Basic elements of hypertrophic cardiomyopathy.

Endomyocardial biopsies were taken from the right ventricular aspect of the interventricular septum in three patients with hypertrophic cardiomyopathy and were subjected to electronmicroscopical examination. Longitudinal sections confirmed already well-established findings. In the transverse sections disarray in the arrangement of the actin filaments and expansion of the myosin lattice, indicating clear overcontraction, were observed. The number of actin filaments varied from seven to 14 per hexagon; a number exceeding 12, however, was found in only one case. From our findings we conclude that overcontraction leads to a progressive deviation of the action filaments during systole caused by double overlap. The majority of these mechanisms results in a "self-impeding contraction" of the fibres. Functionally the excess of actin filaments may provide a balance between the unequal forces of contraction.

Actins↗
PubMed1981

Glomerular basement membrane and mesangial matrix: a comparative study in different vertebrates.

Perfusion fixation of the rat kidneys with aldehydes and alcian blue demonstrates within the glomerular mesangium various components displaying anionic binding sites. These are the surface coat of the mesangial cells, numerous mesangial microfibrils (probably glycoproteins), and polygonal particles (Presumably proteoglycans). These particles lie close to the mesangial cells and form assemblies of various extension within the mesangial matrix as well. In addition, a discontinuous basement membrane can be recognized which surrounds the mesangial cells. In the hagfish glomeruli (fixed without cationic dye), a prominent layer of microfibrils is interposed between mesangial and endothelial cells. Both these cells show incomplete basement membranes.

Animals↗
PubMed1981

Glomerular permeability for proteins of high molecular weight entrapped in liposomes.

The glomerular filtration barrier is known to be negatively charged. Previous experiments have shown the importance of the electrical charge for permeability. We looked for permeability characteristics of proteins entrapped in liposomes with negative and positive charge detecting that the positive charge enables the protein to pass the glomerular filtration barrier.

Animals↗
PubMed1981

Glomerular podocyte cell junctions in nephrotic syndrome. I. Freeze-fracture studies in rat aminonucleoside nephrosis.

Aminonucleoside nephrosis was induced in rats after a single i.p. injection of puromycin aminonucleoside (PAN). Freeze-fracture studies of the glomeruli were done, three, six and ten days after PAN injection. The epithelial filtration slits disappeared six days after PAN injection. On the split plasma membrane of the podocytes three types of cell junctions which apparently were newly formed were seen: 1) single strands (occluding junctions of leaky type); 2) networks of limited extent, composed of strands and particles (maculae occludentes); 3) assemblies of particles or pits (maculae communicantes) connected by single strands. The cell junctions of podocytes were comparable with those found in human nephrotic syndrome. (Kühn et al., 1981).

Animals↗
PubMed1981

Glomerular podocyte cell junctions in nephrotic syndrome. II. Freeze-fracture studies in human nephrotic syndrome.

In six patients with nephrotic syndrome and in two control subjects freeze-fracture studies of isolated glomeruli obtained by needle biopsies were performed. In the nephrotic patients replicas of freeze-fractured podocytes showed an increased number of cell junctions. These were represented by incomplete occluding junctions and communicating junctions (gap junctions). There was morphologically a similarity between the glomerular podocyte cell junctions in human and experimental nephrotic syndrome (Kühn et al., 1981).

Adolescent↗
PubMed1981

Differences in the microfibrillar arrangement of collagen fibrils. Distribution and possible significance.

The microfibrillar arrangement of collagen fibrils has been studied on replicas of freeze-fractured specimens and on thin sections of specimens treated with a 4.0 M guanidinium chloride solution. Collagen fibrils with straight arrangement of their microfibrils usually have a variable diameter and correspond in their distribution to genetical type I and type II collagens. Collagen fibrils with helicoidal arrangement of their microfibrils present a relatively small and uniform diameter and show a tissue distribution similar to that of the genetical type III collagen. The corneal stroma, although predominantly composed of type I collagen, displays collagen fibrils with a helicoidal microfibrillar arrangement, and small uniform diameter. This exception can be explained in consideration of the function of the collagen of the corneal stroma. A close correlation between all the different microfibrillar patterns of the collagen fibrils and their function in the anatomical sites we examined is evident.

Animals↗
PubMed1980

The fine structure of the stomach mucosa of the Llama (Llama guanacoe). II. The fundic region of the hind stomach.

The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron desity of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals.

Aminosalicylic Acid↗