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Three patients presented with an asymptomatic longitudinal pigmented band in a nail. A junctional melanocytic naevus in the nail matrix was suspected; this was confirmed by histological examination in each case. Differential diagnosis and management are discussed, together with a review of the literature. Local excision is considered to be the treatment of choice.
A simple method for calculating the transmittance of three-dimensional photonic crystals is proposed. The crystals are divided into multilayer thin films, and each film is divided into rectangles with a minute width to calculate the effective permittivity of the film by the effective medium theory. Transmittance of the multilayer thin films is calculated with the matrix method. As the number of atomic layers increases, remarkable stop bands appear. When the refractive index of photonic atoms increases, the stop band shifts to a lower frequency, the band widens, and the number of bands increases. Polarization and incident angle dependences are also analyzed. The limit of application for this calculation method is also discussed.
The ultrastructure of the infective oncosphere of the cestode Mosgovoyia ctenoides (Anoplocephalidae) is described. The surface of the infective oncosphere is covered by a thin cytoplasmic layer of tegument connected by a narrow cytoplasmic process with the binucleate subtegumental cell, situated deeper in the body. Below the basal matrix of the cytoplasmic layer of the tegument are situated wide bands of the peripheral, somatic musculature responsible for body movements. The 3 pairs of hooks and their muscles form a complex hook muscle system, responsible for coordinated hook action. Five major types of cells have been distinguished: (1) a binucleate subtegumental cell, (2) a binucleate penetration gland, (3) 2 nerve cells, (4) numerous somatic cells, and (5) about 6 germinative cells. The approximate number of cells is 24 (26 nuclei, including 2 syncytial structures). The results of this study, when compared with other published reports from other cestode taxa, support previous hypotheses that the progressive reduction of oncosphere cells is an adaptive feature in cestode evolution.
Asymptotic confidence bands for generalized nonlinear regression models are developed. These are based on a combination of the S method of Scheffe, together with the delta method which is used to approximate the mean function by a linear combination of the parameters. The approach can be used in any situation where large sample theory can be applied to yield asymptotically normal estimates of the parameters, together with a consistent estimate of the large sample covariance matrix. Alternative formulations for various special cases allow the use of restricted range bands. A number of examples are given, including a pharmacokinetic model, a logit model with a background response rate, and a parametric survival model.
Recent biochemical and immunohistochemical studies have described several components of basement membranes including heparan sulfate proteoglycan, 2 high molecular weight glycoproteins (fibronectin and laminin), and 2 collagen types (IV and V). These collagens have several properties which distinguish them from other types that are located in the interstitium: (a) type IV forms an amorphous, felt-like matrix, and neither IV nor V is found in large, cross-banded fibrils, (b) both have an increased content of hydrophobic amino acids, (c) the precursor (pro) forms are larger than those of interstitial collagens, (d) type IV contains interruptions within the triple helix, and e) both IV and V are resistant to human skin collagenase but are substrates for selected neutral proteases derived from mast cells, macrophages, and granulocytes. By immunofluorescence staining, type IV collagen has been localized to basement membranes at the dermal-epidermal junction, in capillaries, and beneath endothelial cells in larger vessels. Ultrastructurally it has been shown to be a specific component of the lamina densa. Type V collagen has been localized to the pericellular matrices of several cells types and may be specific for extramembranous structures which are closely associated with basal laminae. Other collagenous proteins have been described which may be associated with the extracellular matrix. One of these is secreted by endothelial cells in culture and by peptide mapping represents a novel collagen type. It is secreted under ascorbate-free conditions and is highly sensitive to proteolytic degradation. It has been proposed that a dynamic reciprocity exists between cells and their extracellular matrix which partially determines cell shape, biosynthesis, migration, and attachment. Examples of phenotypic modulation in several of these phenomena have been shown with endothelial cells grown on different substrates and isolated from different vascular environments.
Double minutes of a human breast cancer cell line revealed no centromeres by Cd banding. They cluster at the periphery of metaphase plates, usually encased in a matrix material. They move in anaphase passively with the chromosomes by attaching to the sides or ends of the chromosomes. The two "sister minutes" move to the same pole without separation. Such anomalous mitotic behavior suggests that double minutes are not chromosomes.
Cortisone-treated Buffalo rats have been parabiosed with untreated controls of the same age. The optical and electron microscopy, including histochemistry, of costal cartilage of these rats has been compared with that in single cortisone treated rats, single controls, and control parabiosed with control rats, at 14 and 28 days after parabiosis. Single cortisone-treated rats, in comparison to controls, have shown the greatest alteration in cellular morphology and in the extracellular matrix both at 14 and at 28 days. Cortisone-treated parabiosed rats demonstrate a gradation of these alterations. Cellular alterations include enhancement of lipid and glycogen deposition concrurently with the presence of numerous large cytoplasmic vacuoles containing beaded irregularly-shaped filaments, banded or unbanded collagen-like fibrils, and/or electron dense lamellar bodies. In the extracellular matrix, matrix vesicles, amianthoid fibers, randomly oriented unbanded fibrillar materials, and filament-like materials are most prominent in the single cortisone-treated rats and they are progressively less prominent in the cortisone-treated parabiosed rats, and in the parabiosed and single controls. Calcification of the extracellular matrix follows a similar pattern and is observed initially in pericellular halos of the single cortisone and in cortisone-treated rats parabiosed with controls. Histochemical techniques have shown that chondroitin sulfate is less demonstrable in the single cortisone and in the cortisone-treated parabiosed rats than it is in the single or parabiosed controls at 14 days but, at 28 days, all untreated or treated rats, single or parabiosed are basically comparable. Glycoproteins are prominent in the single cortisone-treated rats both at 14 and at 28 days and, at these same times, they are progressively less prominent in the cortisone-treated parabiosed rats and in the single or parabiosed controls. Many of the cortisone induced alterations in costal cartilage are suggestive of enhancement of the aging process.
The structural and functional diversity of extracellular matrices is determined, not only by individual macromolecules, but even more decisively, by the alloyed aggregates they form. Although quantitatively major matrix molecules can occur ubiquitously, their organization varies from one tissue to another due to their amalgamation with specific sets of minor components. Here, we show that the fibril-associated collagen with interrupted triple helices collagen XVI is unique in that, depending on the tissue context, it can be incorporated into distinct suprastructural aggregates. In papillary dermis, the protein unexpectedly does not occur in banded collagen fibrils, but rather, is a component of specialized fibrillin-1-containing microfibrils. In territorial cartilage matrix, however, collagen XVI is not a component of aggregates containing fibrillin-1. Instead, the protein resides in a discrete population of thin, weakly banded collagen fibrils also containing collagens II and XI. Collagen IX also occurs in this population of fibrils, but at longitudinal locations discrete from those of collagen XVI. This suprastructural versatility of a collagen is without precedent and highlights pivotal differences in the tissue-specific organization of matrix aggregate structures.
Results of studies on the interactions of aldolase and glyceraldehyde-3-phosphate dehydrogenase with erythrocyte ghosts have been reinterpreted by making allowance for possible multivalency of the enzymes in regard to their interactions with matrix sites. It is shown that the curvilinearity of the experimental Scatchard plots may be attributed fully to the formation of enzyme-membrane complexes in which tetravalent enzyme may form crosslinks between several membrane sites. This interpretation of the results is preferable to earlier analyses based on heterogeneity of membrane sites in that (a) it takes into account the tetrameric nature of aldolase and glyceraldehyde-3-phosphate dehydrogenase, and (b) it is consistent with experimental demonstrations that band 3 protein is the sole site for enzyme interaction with the erythrocyte matrix. The dependence on ionic strength of the intrinsic association constant for either interaction is such that the binding of neither aldolase nor glyceraldehyde-3-phosphate dehydrogenase could be detected at ionic strengths in excess of 0.08 I. This finding is discussed in relation to the claims and counterclaims concerning the physiological significance of these interactions between glycolytic enzymes and erythrocyte membranes.
The ultrastructure of sulphate proteoglycans in basophil granules was examined using cytochemical procedures designed to stabilize and visualize these highly anionic macromolecules in situ. Unfixed or glutaraldehyde-prefixed guinea-pig spleen cells were submitted to fixation/staining in 2.5% glutaraldehyde, 0.2% cuprolinic blue (CB; a cationic phthalocyanin dye) and 0.2 or 0.3 M MgCl2 with or without glycosidase treatments. Abundant electron-dense precipitates were present throughout the granule matrix. The stained structures were often arranged in a quasi-crystalline typical banded pattern. Negative control basophils had no electrondense precipitates. Digestion with chondroitinase ABC destroyed the CB-positive electron-dense banded or filamentous patterns while sialidase treatment did not, but led to larger CB-positive filaments in the cytoplasm near the granules. Taking into account their high anionicity, as shown by the stability of dye binding in the presence of 0.3 M MgCl2, and their susceptibility to chondroitinase ABC, the CB-precipitates are assumed to be related to the sulphated proteoglycans previously characterized in basophil granules. The CB-positive crystalline or filamentous network of the granule matrix is also assumed to reflect the in situ location and organization of these intracellular proteoglycans and may be involved in maintaining the shape of the granule.
Reactions of laser-ablated W atoms and H(2) molecules during condensation in excess neon give the WH, WH(2), WH(3), WH(4), and WH(6) hydride products. WH(6) absorptions increase on annealing to allow diffusion and further reaction of H(2) and decrease on photolysis such that six infrared bands can be grouped and assigned to WH(6). Excellent agreement between four observed neon matrix and four DFT calculated W-H stretching modes (two a(1) and two e) and bending and deformation modes (a(1) and e) confirms the present neon matrix preparation of WH(6) and the previous theoretical predictions of a distorted trigonal prism structure which is far from octahedral.
Rat placenta contains virtually no unsaturated (i.e., apo-form) folate binding protein. However, by lowering the pH of a solubilized membrane preparation of this tissue to 3.5, the endogenous bound folate was dissociated from the protein and adsorbed to charcoal. The apo-form of the folate binding protein thus obtained was purified by affinity chromatography using pteroylglutamic acid covalently coupled to Sepharose 4B. A single protein band with an apparent M(r) of 36,000 was observed by SDS-polyacrylamide gel electrophoresis of the eluate from the affinity matrix. Western blot of this preparation using a rabbit antiserum raised with the affinity eluate also identified a single 36 kDa protein band. However, peptide sequencing of the N-terminal region of the proteins in the affinity eluate established that it contained two homologous proteins. Computer alignment of the first 22 N-terminal amino acids of each rat placental protein with human, bovine milk and mouse folate binding proteins showed 50-64% identical homology and 27% homology when the eight proteins were aligned together. The affinity of both rat proteins is highest for pteroylglutamic acid (Ka = 1.6.10(9) l/mol) lower for N5-methyltetrahydrofolate and substantially lower for N5-formyltetrahydrofolate. In the dose-response range studied there was no apparent affinity for methotrexate. The folate binding proteins could be released from a preparation of placental membranes using phospholipase C indicating that these proteins belong to the class of proteins anchored to the plasma membrane by a glycosyl phosphatidylinositol adduct.
Numerous vesicles were observed among the microtubules of the "preprophase" band in prophase cells from root tips of Allium cepa. The content of these vesicles looks similar to the matrix of adjacent cell walls, and these vesicles often appear to be involved in exocytosis. In addition, the cell walls perpendicular to the plane of (beneath) the preprophase band are often differentially thickened compared to the walls lying parallel to the plane of the band. Our interpretation of these observations is that the preprophase band may direct or channel vesicles containing precursors of the cell wall to localized regions of wall synthesis. The incorporation of constituents of the cell wall into a narrow region defined by the position of the preprophase band may be a mechanism that ensures unidirecitonal growth of meristematic cells.
We have used a sol-gel technique to obtain optically transparent hydrogels in which water is confined within a 3D silica matrix. In this work we report X-ray scattering and dielectric spectroscopy measurements on samples having different aging times and compare them with previously obtained results with near-infrared (NIR) absorption spectroscopy. X-ray scattering at room temperature enables to characterize the structure and size of the matrix pores and the non-uniform distribution of water inside the hydrogel. Broad band dielectric spectroscopy in the temperature range 130-280 K enables to study water dynamics. In aged hydrogels two relaxations are clearly evident and show characteristic temperature dependence. The faster relaxation has an Arrhenius behavior in the whole temperature range investigated with an activation enthalpy of approximately 50 kJ/mol; it is attributed to water molecules strongly interacting with the silica matrix. The slower relaxation has a markedly non-Arrhenius behavior which can be fitted with a Vogel-Fulcher-Tamman (VFT) relation with critical temperature of approximately 100 K and activation enthalpies of 35 and 95 kJ/mol at 300 and 170 K respectively; it is attributed to water molecules within the pores that do not interact strongly with the matrix and behave collectively. The VFT temperature dependence of the dielectric relaxation time suggests that this water does not crystallize, in agreement with previous results from NIR spectroscopy.
The adaptive changes that develop in the pressure-overloaded left ventricular (LV) myocardium include cardiomyocyte hypertrophy and interstitial fibrosis. Although the former is known to depend to a sizeable extent on sympathetic (over)activity, little information exists whether the same applies to the latter, ie, whether excess catecholamine exposure contributes to the imbalance between collagen deposition by fibroblasts and degradation by matrix metalloproteases (MMPs), eventually leading to LV collagen accumulation. Sprague-Dawley rats were subjected to abdominal aortic banding (B) or sham operation (S) and treated with beta-blockade (Bb, oral propranolol, 40 mg/kg per day), chemical sympathectomy (Sx, 6-hydroxydopamine, 150 mg/kg intraperitoneal twice per week) or vehicle (Vh). Ten weeks later, systolic blood pressure, LV weight, collagen abundance (computer-aided histology), zymographic matrix metalloproteinase (MMP)-2 activity and its specific tissue inhibitor concentration (TIMP-2) were measured. Both sympathectomy and beta-blockade failed to attenuate the banding-induced blood pressure elevation but significantly attenuated the attendant LV hypertrophy. As expected, pressure-overload hypertrophy was associated with interstitial fibrosis (collagen: 4.37+/-1.23% BVh versus 1.23+/-0.44% SVh, P<0.05), which was abolished by sympathectomy (2.55+/-1.31%, P=not significant versus SSx) but left unchanged by beta-blockade (4.11+/-1.23%, P<0.05 versus both SBb and BSx). beta-blockade, but not sympathectomy, was also associated with an increased TIMP-2/MMP-2 ratio (P<0.05), indicating reduced interstitial collagenolytic activity. In separate groups of banded and sham-operated rats, treatment with the alpha-receptor blocker doxazosin (10 mg/kg per day) displayed similar antifibrotic and biochemical effects as sympathectomy. Thus in the course of experimental pressure overload, the sympathetic nervous system plays a major pro-fibrotic role, which is mediated via alpha-adrenergic but not beta-adrenergic receptors.
Fluorescence line-narrowing (FLN) spectroscopy at 10 K was used to study the effect of high pressure through the prosthetic group in horseradish peroxidase (HRP), which was Mg-mesoporphyrin (MgMP) replacing the heme of the enzyme. The same measurement was performed on MgMP in a solid-state amorphous organic matrix, dimethyl sulfoxide (DMSO). Series of FLN spectra were registered to determine the (0, 0) band shape through the inhomogeneous distribution function (IDF). In the range of 0-2 GPa a red-shift of the IDF was determined, and yielded the isothermal compressibility of MgMP-HRP as 0.066 GPa(-1), which is significantly smaller than that found earlier as 0.106 GPa(-1) by fine-tuning the pressure in the range up to 1.1 MPa. The vibrational frequencies also shifted with pressure increase, as expected. The compressibility in the DMSO matrix was smaller, 0.042 GPa(-1), both when the pressure was applied at room temperature before cooling to 10 K, or at 10 K. At 200 K or above, the bimodal (0, 0) band shape in DMSO showed a population conversion under pressure that was not observed at or below 150 K. A significant atomic rearrangement was estimated from the volume change, 3.3 +/- 0.7 cm(3)/mol upon conversion. The compressibility in proteins and in amorphous solids seems not to significantly depend on the temperature and in the protein it decreases toward higher pressures.
The iridocorneal-endothelial syndrome is a disease of the ocular anterior segment characterized by corneal failure, glaucoma and iris destruction. Specular photomicroscopical and histological studies suggest the disorder is caused by a population of abnormal corneal endothelial cells. In other corneal endotheliopathies Descemet's membrane, the basement membrane underlying the endothelial cells, is disfigured by the presence of an abnormal region of extracellular matrix termed a posterior collagenous layer, which is laid down by the diseased endothelial cells. In this study we sought to establish the typical morphology and composition of Descemet's membrane in the iridocorneal-endothelial syndrome. Ultrastructural examination of Descemet's membrane in 27 keratoplasty specimens identified three morphologic patterns. In the majority there was a posterior collagenous layer which in all cases consisted of an anterior layer of wide-spaced collagen and a posterior layer of microfibrils embedded in an amorphous matrix. In four specimens which did not possess a posterior collagenous layer the anterior banded zone of Descemet's membrane was absent. In five corneas Descemet's membrane was normal. The composition of the posterior collagenous layer was examined by immunoelectron microscopy (five corneas) and histochemistry (six corneas). Collagen Types I, III, V, VI and VIII, fibronectin, tenascin and oxytalan were microfibrillar components, collagen Type VIII formed wide-spaced collagen whilst laminin was present in the amorphous matrix. The stereotyped derangements of structure and composition identified in the endothelial basement membrane may significantly influence the pathobiology of this disorder.
The effect of moult on eggshell mechanical properties, on composition and concentrations of organic matrix components and on eggshell microstructure was investigated. The observed changes were studied to understand the role of organic matrix and eggshell microstructure in eggshell strength. Moult was induced by zinc oxide (20 g zinc/kg diet) in 53 ISA Brown laying hens at 78 weeks of age. No difference was observed for egg or eggshell weights after moult. In contrast, moult improved the shell breaking strength (28.09 vs 33.71 N). After moult, there was a decrease in the average size of calcite crystals composing the eggshell and in their heterogeneity, whereas crystal orientation remained basically the same. After moulting, the total protein concentration in eggshell increased slightly. The comparisons of SDS-PAGE profiles of the organic matrix constituents extracted before and after moulting showed changes in staining intensity of certain bands. After moult, bands associated with main proteins specific to eggshell formation (OC-116 and OC-17) showed higher staining intensity, while the intensity of the egg white proteins (ovotransferrin, ovalbumin and lysozyme) decreased. ELISA confirmed the decrease in ovotransferrin after moult. Its concentration was inversely correlated with breaking strength before moult. These observations suggest that changes in eggshell crystal size could be due to changes in organic matrix composition. These changes may provide a mechanism for the improvement in shell solidity after moulting.