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PubMed1988

[Erythropoietic protoporphyria. Ultrastructure of the basal pericapillary complex in the superficial dermis].

An ultrastructural investigation of erythropoietic protoporphyria reveals the high complexity of the basal complex that surrounds the superficial capillaries. There is a tremendous replication of the usual basement membrane, but in chips, with the constitution of an uneven network within an amorphous substance. Few collagen fibrils and microfibrils are present. Furthermore the architectural upheaval is characterized by the penetration of endothelial cell pseudopoda and of slender processes of perithelial cells. The basal complex is clearly encompassed by a layer of epithelial cells. The overall thickness reaches 5 micra.

Basement Membrane↗
PubMed1988

Amino acid sequence of the triple-helical domain of human collagen type VI.

The complete amino acid sequence of the triple-helical domain of human collagen VI was deduced from sequences of appropriate cDNA clones and confirmed to about 50% by Edman degradation of tryptic peptides. This domain consists of three different peptide segments containing some 335-336 amino acid residues originating from central portions of the alpha 1 (VI), alpha 2(VI), and alpha 3(VI) chains, respectively. Sequence identity in the X/Y positions of the Gly-X-Y repeats is rather low (10-15%) between the chains. Peculiar features of these sequences include 3 cysteine residues about 50 (alpha 3(VI)) and 89 (alpha 1(VI), alpha 2(VI)) residues away from the N-terminus and several Gly-X-Y interruptions clustered in the C-terminal two-thirds of the triple helix. These structures are presumably required for cross-linking collagen VI oligomers and for super-coiling of triple helices in the dimers. Other features include 11 Arg-Gly-Asp sequences, some of which are likely to be used as cell-binding sites, and four Asn-X-Thr sequences, allowing N-linked glycosylation along the triple helix. Junctional areas close to the helix contain short, cysteine-rich segments which may seal the triple-helical domain through disulfide bond formation, endowing it with high stability. These features, together with a low sequence homology to fiber-forming and basement-membrane collagens, document the unique character of collagen VI, whose triple helix is specifically adjusted for forming microfibrils in tissues.

Amino Acid Sequence↗
PubMed1988

Ultrastructural study of hypervitaminosis D induced arterial calcification in Wistar rats.

Hypervitaminosis D produces extensive vascular alterations which are similar to Monckeberg's calcinosis. The present study was undertaken to examine early changes in vascular ultrastructure of rats receiving tap water supplemented with either calcium chloride or a relatively low dosage of irradiated ergocalciferol ad libitum for 21 days. Untreated rats received normal tap water ad libitum. A significant increase in serum calcium levels was obtained in hypervitaminosis D treated rats. Calcium deposits were seen near the internal elastic lamina, within new elastic elements and around degenerating smooth muscle cell fragments in the extracellular organic matrix of hypervitaminosis D treated rats. Calcium deposits were not detected in vascular sections from untreated rats or those receiving calcium chloride. A complex pathogenesis of vascular lesions produced by hypervitaminosis is suggested. One possible pathogenic mechanism for calcification of elastic matrix may be via altered microfibrils. Our data support this hypothesis and indicate that much lower levels of vitamin D administration, compared to other reports, produce considerable vascular calcinosis in this experimental preparation. Several hypotheses regarding possible mechanisms of pathologic calcification are discussed.

Animals↗
PubMed1988

[Comparative morphological study of the peritoneal mesothelium and the germinal epithelium of the ovary. Histogenetic evidence for endometriosis].

The purpose of this study was to evaluate comparatively the morphology of germinal epithelium and of peritoneal mesothelial cells in women with and without endometriotic foci. In women without enometriotic foci, transmission electron microscopy revealed that plasma membranes of both cell types can form villous process, and that tonofilaments can be found in the cytoplasm; the microfibrils are well defined and may be arranged in perinuclear location or closely packed on the surface. Desmosomes are occasionally found in both cell types. In endometriotic foci, located either in the peritoneum or in the ovary, invaginations of the mesothelium into the underlying stroma are frequently observed, contiguous to well defined endometriotic tubules, or glandlike crypts. These structures are lined by a layer of cuboidal or high columnar cells. The cell membranes are well defined and run parallel to one another; small widening of the intercellular spaces is occasionally associated with a desmosome in the apical portion of the cell. These features may reflect Mullerian induction.

Adult↗
PubMed1988

Pulmonary elastic fiber degradation in paraquat toxicity. An electron microscopic immunohistochemical study.

To study the morphologic alterations of pulmonary elastic fibers in cynomolgus monkeys with paraquat toxicity, peroxidase- and ferritin-labeled antielastin antibodies were used for the light and electron microscopic localization of elastin. One week after paraquat, alveolitis, tissue damage and alveolar dilatation were present; elastic fibers were frayed and more diffusely and intensely stained than those of control animals. In the latter, staining was localized in peripheral regions of the amorphous components and, to a lesser extent, in some microfibrils of elastic fibers. At 3 to 4 weeks, diffuse staining was evident in damaged interstitial elastic fibers and in newly formed elastic fibers in areas of intraalveolar fibrosis. At 8 weeks, the interstitium contained many elastic fibers which showed staining only in peripheral regions of the amorphous components. These observations suggest that: 1) preembedding immunohistochemical staining for elastin is localized in peripheral regions of normal elastic fibers because the antielastin antibody can penetrate into mature and undamaged amorphous components only to a very limited extent; 2) in early stages of paraquat toxicity this staining is more diffuse and intense because elastase from inflammatory cells partially degrades the elastic fibers and permits greater penetration of the antibody into the amorphous materials; 3) in later stages the staining pattern returns to normal as inflammation subsides and elastic fibers are repaired; however, newly formed elastic fibers in areas of intraalveolar fibrosis stain diffusely, reflecting increased penetration of the antibody because of immaturity and incomplete cross-linking, and 4) degeneration of elastic fibers of alveolar walls in paraquat lung may lead to alveolar dilatation, which is associated with irregular fibrosis and constitutes one of the processes of pulmonary structural remodeling in paraquat lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Ultrastructural characteristics of elastogenesis in the major arteries of the canine hindlimb during leg lengthening].

In mature dogs ultrastructural peculiarities of elastogenesis in femoral and anterior tibial arteries have been studied at various stages of the bone elongation after Ilizarov method. From the end of the 1st week of distraction, metabolic activation of intimal smooth muscle cells is revealed, from the 2d week--in the middle tunic, and on the 5th-6th week--fibroblasts of adventitia of the arteries investigated, directed to biosynthesis of intracellular predecessors of elastin and microfibrils of the elastic fibers. This results in activation of elastogenic processes, elastic structures in all three tunics of the arteries are observed to newly form and rearrange. The factor that stimulates and maintains elastogenesis is strain of extension, that occurs in the vessels during the experiment. Elastogenesis in the major arteries, when the extremity is elongated, has much in common with development of elastic components in the vascular wall in animals during the process of physiological growth.

Animals↗
PubMed1986

Control of shoot apical development via cell division.

Cell division in plants not only partitions the protoplast but also provides the architectural framework for plant form. The shape of the shoot apical meristem is produced and maintained by gradients in the rate and plane of cell division, from the summit to the base of the apical dome, which also determine the region in which primordia can be formed. In Pisum leaf initiation is mainly the result of changes in the frequency of periclinal divisions at the leaf site whereas in Silene an increase in the rate of cell division seems more important since periclinal divisions are always present. Periclinal divisions may be permissive of primordium initiation rather than causal and may define the maximum area over which primordia can form. The occurrence in Pisum and Silene of periclinal divisions which do not seem to be related to concurrent outward growth suggests that the plane of division and the direction of growth may be controlled separately and in different ways. The control of outward growth during primordium initiation may lie in the epidermis, which necessarily grows faster at the leaf site. The initial orientation of epidermal growth at the primordial site, inferred as being normal to the plane of cell division, is predominantly longitudinal in Pisum but transverse in Silene. Longitudinal growth becomes dominant later in leaf development in Silene, as in Pisum. Several lines of evidence suggest a crucial role for the epidermis in the initial stages of primordium formation although the initial orientation of division planes in it may be concerned more with the shape of the young leaf than with initiation itself. In flower initiation primordial size becomes reduced, and in Silene there are alternations of higher and lower rates of cell division in successively initiated primordial types. A fuller understanding of the role of cell division in apical growth depends on better knowledge of the functional relationships between the plane of cell division, the orientation of microtubules and wall microfibrils, and the effect that division in one cell has on its neighbours.

Cell Division↗
PubMed1986

[Effect of various anti-cancer drugs on human renal cell carcinoma serially transplanted into nude mice].

Using two xenografts of human renal cell carcinomas serially transplanted in nude mice (AM-RC-1 and AM-RC-6), both of which maintained the basic histologic features of the original tumor and showed a constant growth rate, the effects of various anticancer agents against 2 target tumors were evaluated. MitomycinC (MMC), adriamycin (ADM), cisplatinum diaminodichloride (CDDP), 5-fluorouracil (5FU), 5-fluro-2'-deoxy-beta-uridine (FUDR) and human lymphoblastoid interferon (HLBI) against AM-RC-1, and MMC, ADM, CDDP, vinblastin (VBL) and etoposide (VP-16) against AM-RC-6. Drugs other than HLBI were administered 3 times in total every three to five days by intraperitoneal injection according to Battelle Columbus Laboratories Protocol and HLBI was injected daily for 10 days intraperitoneally. Anti-cancer effects were evaluated based on tumor growth curve and changes of histologic findings. In terms of tumor growth only MMC (in a dose of 3 mg/kg) revealed a statistically significant inhibitory effect against both AM-RC-1 and AM-RC-6 (respectively P less than 0.001 and P less than 0.05). Concerning AM-RC-1, a significant difference (P less than 0.01) was recognized in the ADM group (5 mg/kg) at the time of the second administration, but evaluation could not ultimately be done owing to appearance of acute toxity after the last dose. The most remarkable histologic changes by light microscopy were recognized in the MMC group (in a dose of 3 mg/kg) against AM-RC-1. They were degenerative findings such as intracellular and nuclear vacuolation, karyorrhexis, karyolysis, karyopyknosis and marginal hyperchromatosis, which corresponded to grade IIa of the classification of the National Cancer Center. The other drugs administered to AM-RC-1 exhibited only grade O to grade I changes. On the other hand, in AM-RC-6, histologic changes were mild (less than grade II) for all the drugs. Electron microscopic features were as follows. AM-RC-1: Marked increase of vacuole of organella was observed and lumens were filled with a large quantity of debris in MMC group (3 mg/kg). In the ADM group (5 mg/kg) there was debris in lumens, although almost no changes of organella were seen. CDDP groups (both 5.6 mg/kg and 2.8 mg/kg) showed autophagic vacuole in the cytoplasm and increased collagen fibers in the stroma but little changes of organella. AM-RC-6: Mild intracellular vacuolation was recognized in the MMC group (3 mg/kg). Watery degeneration and microfibrils were found in the cytoplasm in both ADM (5 mg/kg) and CDDP (5.6 mg/kg, 2.8 mg/kg) groups.

Animals↗
PubMed1987

Nylon brush macular amyloidosis.

Long-term use of a nylon brush for back scratching by a 53-year-old white woman was associated with the development of typical macular amyloidosis. EKH4 monoclonal antikeratin antibody, which recognizes 50-kd neutral and acidic keratin species, labeled this amyloid. Confirmation of amyloid substance in the lesion included positive staining with Dylon and thioflavin T; immunohistochemical reactions with monoclonal and polyclonal antibodies against elastic fiber microfibrils (NKH1 and anti-P component), immunoglobulins (IgG, IgM, and IgA), and complement (C3); and electron microscopic identification of 6- to 10-nm straight filaments. Type IV collagen staining demonstrated a breakage and/or thickening of the dermoepidermal basement membrane above the amyloid deposition in the papillary dermis. Electron microscopic findings confirmed this phenomenon.

Amyloidosis↗
PubMed1987

In-vitro demonstration of a complicated atherosclerosis-like lesion.

Smooth muscle cells derived from the media of adult rat aorta were grown on elastin membranes for up to 3 weeks in cell culture. Cell degeneration was evident by the 4th day and increased with time. At the end of the experiment necrotic and calcified areas were prominent. The basic feature of cell degeneration was dissolution of myofilaments; the disintegrating cytoplasm usually contained numerous glycogen granules. Increased electron density of the mitochondrial matrix and fat globules were seen and nuclei showed dilution of chromatin or pyknosis. Abundant cellular debris, vesicular structures and microfibrils were found in the extracellular space.

Animals↗
PubMedDate not supplied

Morphological changes in small vessels on endomyocardial biopsy.

Small vessel disease has been described in various cardiac conditions including diabetes mellitus, amyloidosis, and connective tissue disease. Less well understood is the incidence and morphological features of small vessel disease in patients with myocardial disease of unknown etiology. This study examines the incidence, clinical presentation, and pathological changes of small vessel disease in patients with normal epicardial coronary arteries undergoing endomyocardial biopsy. Biopsy specimens in 110 consecutive patients were analyzed by light and electron microscopy. Small vessel abnormalities were present in 16 patients (14.6 percent) of whom five patients had associated hypertension and 11 patients had idiopathic small vessel disease. There were six males and 10 females with a mean age of 53 (26 to 76) years. Clinical presentations were arrhythmias, heart failure, or chest pain. The left ventricular ejection fraction was reduced (less than 50 percent) in 12 of these 16 patients. The morphological features of small vessel disease included marked thickening of the arterial wall owing to subendothelial deposits of heterogeneous electron dense materials consisting of microfibrils, collagen and elastic fibers, cellular debris, and other amorphous substances. Subendothelial deposits comprised a mean 60 percent (40 to 76 percent) of the arterial wall thickness.

Adolescent↗
PubMed1986

The role of glycosaminoglycans in anuran pigment cell migration.

The migratory pathways of neural crest-derived pigment cells were examined in two anurans, Xenopus laevis and Discoglossus pictus, and correlated with the distribution of glycosaminoglycans (GAG) in the extracellular matrix (ECM) of these pathways. In Xenopus, melanophores in the trunk reach the dermis by initially migrating ventrally, between the neural tube and somites, and then by migrating through the somites to reach the subectodermal space. In Discoglossus, melanophores, iridophores, and xanthophores migrate laterally over the dorsal margin of the somites to reach the dermis. GAG was identified in the light microscope using alcian blue staining and in the electron microscope using ruthenium red staining. The ECM at the dorsal entrance to the lateral pathway in Xenopus and in young Discoglossus (at a stage prior to invasion by pigment cells) is filled with 25-50 nm chondroitin sulphate proteoglycan aggregates. When this ECM in Xenopus is digested in vivo with chondroitinase ABC, melanophores enter the lateral pathway. In older Discoglossus embryos, the migration of pigment cells into the lateral pathway is correlated with increases in the space between the ectoderm and somites and in the number of hyaluronate microfibrils. These observations suggest that chondroitin sulphate proteoglycan in the subectodermal ECM restricts the migration of pigment cells into the lateral pathway by limiting the amount of space for migration and possibly by acting as a less adhesive migratory substratum than the ventral pathway, and that in Discoglossus hyaluronate opens spaces permitting the migration of pigment cells directly over the dorsal margin of the somites.

Animals↗
PubMed1986

Endothelial cells in the rectal venous plexus. An electron microscopic study.

The endothelial cells of the rectal venous plexus were studied by electron microscope. The endothelial cytoplasm contained numerous specific granules, intracytoplasmic filaments, and 'anchoring filaments'. The present observations suggest that specific endothelial granules are formed in the Golgi apparatus. Thin 50-70 A and thick filaments 100-120 A were found in the endothelial cytoplasm. Also anchoring filaments between the plasma membrane of the endothelial cells and the underlying basement membrane (or subendothelial microfibrils) were present. The cytoplasmic filaments as well as the anchoring filaments are thought to be a support for the endothelial cells, functioning as a cytoskeleton.

Actin Cytoskeleton↗
PubMed1986

The ultrastructure of hemolymph cells of the land slug, Incilaria fruhstorferi Collinge (Gastropoda: Pulmonata).

3 morphologically distinct hemolymph cell-types, Type I, II and III, were found in the hemolymph of the land slug, large Japanese native slug, Incilaria fruhstorferi Collinge. Type I cell, measuring approximately 35 microns in diameter, had extensive pseudopodia with supporting ribs and a kidney-shaped or lobulated nucleus. Sometimes it possessed long filopodia (approximately 50 microns) with branched fibers. It contained residual bodies, multivesicular bodies, Golgi apparatus, free ribosomes and glycogen-like deposits. Type II cell, approximately 5 microns in diameter, did not form large pseudopodia, had a higher nucleus to cytoplasm ratio. It contained scattered free ribosomes surrounding the round nucleus. Type III cell, approximately 75 X 15 microns, was a fibroblast-like cell. It contained microfibrils at the rim of perinuclear cytoplasm and possessed collagen-like fibers outside of the cytoplasmic membrane. Numerous plate-like structures, which had not been reported yet, were usually observed. They, measuring 1 to 5 microns in diameter, were oval, but when in contact with glass, they possessed long and fine fibers. They lacked nucleus.

Animals↗
PubMedDate not supplied

[Electron microscopic study of pectin solutions].

Electron microscopic study was carried out of the structure of pectin 0.01% aqueous solutions according to esterification degree at different pH medium. Preparations were prepared by freezing-drying method of solution drop on the formvar film and by the negative contrasting method. Microfibrils of 60-180 A diameter were found. Their aggregation increased with a decrease of the charge of pectin macromolecule (increase of esterification, decrease of pH).

Chemical Phenomena↗
PubMed1985

[Localization of different types of collagen (I, III, IV, V) in the connective tissue of the popliteal artery and skeletal muscle of man (immunoelectronmicroscopic analysis)].

By means of immunoperoxidase and immunoferritin techniques collagen of the I, III, IV and V types has been revealed in cryostat sections of the popliteal artery and in the musculus quadriceps of the femur. Areas of the vascular wall without any macroscopical signs of lesions have been investigated. They have been obtained from amputated extremities of young persons (17-22 years old), and muscle pieces have been taken during operations performed in the knee joint. After certain immunocytochemical procedures the cryostat slices are embedded in mixture of epon 812 and araldit, non-contrasted ultrathin slices are examined in the electron microscope JEM 100CX. Collagen of the I and III types is revealed in fibrills 20-80 nm thick either with or without cross striation, as well as in microfibrills. Collagen of the III type in the intercellular substance of the arterial wall occurs in nonfibrillar form. Collagen of the IV type is revealed in basal membranes of the smooth muscle cells of the arterial wall, of the muscle fibers and of endothelium of blood capillaries of the skeletal muscle. Collagen of the V type is found as accumulations having various size and form; they localize in many places of the intercellular substance of the arterial wall. A tight contact is revealed between the formations including collagen of the V type with drops of elastin and elastic fibers. A suggestion is made that collagen of the V type participates in formation of elastic fibers.

Adolescent↗
PubMed1986

Prelesional events in atherogenesis. Accumulation of extracellular cholesterol-rich liposomes in the arterial intima and cardiac valves of the hyperlipidemic rabbit.

Biochemical, physiologic, and ultrastructural modifications which appear in the aortic intima and atrioventricular valves before monocyte diapedesis and foam cell formation were investigated in rabbits fed a cholesterol-rich diet. In the first 2 weeks of the diet, while plasma beta-VLDL cholesterol was increased up to 15-fold, the intima showed an enhanced uptake and deposition of dietary 3H-cholesterol, 125I-beta-VLDL, and the fluorescent beta-VLDL-1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine conjugate. beta-VLDL-gold complex perfused in situ was transcytosed across endothelium by plasmalemmal vesicles. Concomitantly, within the intima, a progressive accumulation of extracellular densely packed uni- or multilamellar vesicles took place. These commonly occurred in cell-free subendothelial spaces and were not associated with any sign of cytolysis. In freeze-fracture preparations, these vesicles appeared as smooth surfaces, suggesting the absence of translamellar proteins. Upon incubation with filipin, these extracellular liposomes (EL) displayed characteristic approximately 20 nm filipin-sterol complexes, revealing the presence of preparations unesterified cholesterol in the phospholipid lamellas. EL deposition was paralleled by proliferation of basal lamina-like material, microfibrils, and proteoglycans, and continued to increase during foam cell formation. For the entire period of our experiments, the endothelium was morphologically intact, and no platelet involvement was detected. The results show that an early prelesional ultrastructural change in lesion-prone aortic and valvular areas is the accumulation of extracellular phospholipid liposomes rich in unesterified cholesterol.

Animals↗