bluuebunny/crossref_metadata_2025 huggingface dataset:
Axial Yarn Crimping Effects in Braided Composite Materials
Authors: West Alison C. , Adams Daniel O.
Published: April 2011

Braided composite materials develop undulations or crimping in the axial yams when infiltrated with resin, compacted, and cured. This crimping is suspected of producing significant reductions in strength, particularly under compressive loading. In this study, the effects of axial yam crimping were investigated in two-dimensional triaxially braided composite materials under static compressive loading. A methodology was developed to fabricate carbon/epoxy braided composites with minimal axial yam crimping by tensioning the axial yams during the cure process. The compressive strength of braided composites with tensioned axial yams was compared to that of braided composites manufactured in a conventional manner, which produced significant axial yam crimping. Axial yam crimping produced a 30% reduction in axial compressive strength. The axial stiffness, transverse stiffness, and transverse strength were not significantly affected by axial yam crimping. TEXCAD, a mechanics of materials based analysis program, correctly predicted stiffness values but underpredicted the reduction in axial compressive strength due to axial yam crimping. These results suggest that high compaction pressures, which result in greater yam crimping in addition to high fiber volume fractions, may not produce optimal compressive strength performance. These results illustrate the importance of minimizing axial yam crimping for compressive strength critical applications of braided composite materials.
Local Effects in Stiffened Composite Tubes under Generalized Plane Deformation
Authors: Hersh Cheryl L. , Herakovich Carl T.
Published: April 2011

A two-dimensional, curvilinear, isoparametric, finite element is used to study local curvatures and interlaminar stresses in laminated composite tubes with laminated stiffeners running the length of the tube. The generalized plane problem is analyzed by considering a generic transverse cross section of the stiffened tube to provide three-dimensional states of stress. Discrete layers of the tube and the stiffener are modeled explicitly, providing an accurate and detailed representation of local effects. Cross-ply, angle-ply and general laminate configurations are studied for axial, torsional and internal pressure loadings that are constant along the length of the tube. It is shown that local curvatures and interlaminar stresses can be significant and variable and depend upon the laminate configuration and loading conditions.
Energy Absorption Characteristics of Stitched Composite Sandwich Panels
Authors: Raju K. S. , Tomblin J. S.
Published: April 2011

The energy absorption characteristics of sandwich panels with through-the-thickness stitches, under edgewise compression, was investigated by conducting static crush tests. The effects of stitch row spacing on the sustained crush load were of particular interest. Also, the effects of the stitch spacing on the instability preceding the crush failure mode was investigated using finite element analysis. The analysis indicated that the local instability mode was influenced by the stitch row spacing only when the spacing was less than the semi-wavelength of wrinkles that would develop in the absence of stitches. The static crush tests showed that the average sustained crush load increases with reduced stitch row spacing and thereby increasing the total energy absorbed. The other parameters of interest that were investigated were the load ratio and the load uniformity index.
Permeability Characterization of Different Architectural Fabrics
Authors: Ma Yulu , Shishoo Roshan
Published: April 2011

The transient permeabilities and steady-state permeabilities of five different architectural glass fabrics were measured using one-dimensional experiments. The fabric architectures include 3-dimensional structure, random distributed fiber mat with stitches and knitted fabrics. The influence of the test liquids on the permeability measurements was investigated us3ing corn syrup, vinyl ester resin and epoxy resin. The experimental results show that the influence of the test liquids on permeability measurement is small if the simulated test fluids are properly selected. The relationship between permeability and porosity was also investigated. The experimental results indicate that the relationship between permeability and porosity can be expressed as an approximated exponential function. The permeability decreases dramatically as the porosity is reduced to about 0.65. The transient permeability of all fabrics used in the experiments exhibits the characteristic that it increases as the flow front moves forward under the experimental conditions, but the evolution is different. It reflects the influences of the fabric architecture on fabric permeability. The experimental results also point out that reproducible results can be obtained using one-dimensional permeability measurement technique provided that the fiber reinforcements are prepared very carefully and the edge effects are minimized.
Constraint Effects on Energy Absorption in Unidirectional PMC Tubes
Authors: Abdel-Haq M. , Broggiato G. B. , Newaz G. M.
Published: April 2011

An investigation was carried out to understand the effect of an external constraint on the failure modes and energy absorption capability of unidirectional polymeric composite (PMG) tubes. The constraint was a steel ring that was tightened on the outside of the tube. This ring could slide during tube crushing. The tightness of the ring was determined using a strain gage positioned on the ring. The effect of the constraint was shown to depend on the initial position of the ring along the tube. The study was performed on fiberglass/polyester tubes and the results showed that the external constraint not only can improve the specific energy absorption of the tubes, but also can reduce significantly the undesired high initial peak loads. A nonlinear finite element approach was used to model the fundamental failure modes that dominate the energy absorption of the tubes with an external constraint. These modes including delamination and longitudinal crack propagation (splitting), were modeled using the finite element code ABAQUS. A user friendly FOR-TRAN subroutine was implemented to the code to incorporate the material failure model for predicting the fiber/matrix failures that occur as crushing is experienced by the tube. The predicted model results compared well with the experimental data for the various crushing stages of the polyester tubes.
Delamination Onset Prediction in Mechanically Fastened Joints in Composite Laminates
Authors: Camanho P. P. , Matthews F. L.
Published: April 2011

A three-dimensional finite element model is created to simulate a mechanically fastened joint in a composite laminate. Using the results from the finite element model, a spline approximation for the through-thickness stress is applied in order to determine the stress state at the interfaces between the layers. A delamination onset criterion is then applied at each interface. After validation, the model is used to assess the effects of stacking sequence and clamping pressure on the delamination onset loads and surfaces. It is concluded that "blocked" laminates lead to lower delamination onset loads and larger initial delaminated regions. Finger-tight and clamped joints have higher delamination onset loads and smaller initial cracked regions than pin-loaded joints. These results are in agreement with experimental observations, but no significant difference is detected between finger-tight and clamped joints. It is therefore concluded that the through-thickness pressure has an effect not only on damage initiation but also on damage growth, as well as in the load transferred by friction between the washer and the laminate.
The Effect of Varying Thickness on the Buckling of Orthotropic Plates
Authors: Meink Troy E. , Huybrechts Steven , Ganley Jeff , Shen M. H. Herman
Published: April 2011

Although stability failure of constant thickness plates is a fairly well understood problem, buckling of plates with varying thickness has seen little research. This is not a common problem, but buckling of varying thickness plates does occur, as in the case of Advanced Grid Stiffened structures. These structures are characterized by lattices of rigidly connected rib stiffeners. While real-world Advanced Grid Stiffened structure ribs are modeled as orthotropic plates, they often have complex cross-sections (i.e., varying thickness). Unfortunately, failure analysis techniques for these ribs have been limited to rectangular cross-sections. To address this shortcoming, a buckling theory is presented for orthotropic plates of varying thickness. Orthotropic plates with both linear and hourglass thickness variations are considered. These are common grid structure cross-section geometries resulting from existing manufacturing processes. For both geometries, results are given that allow designers to predict how these plates will behave, relative to a constant thickness plate, for a variety of material properties and plate aspect ratios.
The Effective Conductivities of Composites with Cubic Arrays of Spheroids and Cubes
Authors: Kim Jae Young , Yoon Byung Jun
Published: April 2011

A boundary element method is developed for computing the effective conductivity of a composite material containing periodic arrays of particles of arbitrary shape. Utilizing the periodic nature of the problem, steady conduction through a unit cell is analyzed by solving the integral representation of the Laplace equation. The accuracy of the method is validated by comparing the numerical results with analytic solutions for periodic arrays of spherical and spheroidal particles, in particular at high particle volume fractions. The utility of the boundary element method is demonstrated by determining the effective conductivities of simple-cubic, body-centered-cubic, and face-centered-cubic arrays of spheroids and cubes over the entire range of the particle volume fraction.
Variant Finite Element Applications to Axisymmetric Wave Dispersion Analysis of Cylinders
Authors: Mazoch T.
Published: April 2011

The dispersion of the axisymmetric stress waves propagated in the infinite cylindrical bar and hollow cylinder is studied. A modification for this special case of the author's general semianalytical FE approach, and other-alternative FE approach (for the hollow cylinder only) are suggested. Both approaches are applicable to arbitrary cases of anisotropy. The comparisons of the semianalytical approach with regard to exact solutions in solving the dispersion of torsionless waves propagated in the isotropic bar and the isotropic hollow cylinder show excellent agreements. The approach is demonstrated on the case of the anisotropic material-unidirectional composite boron-epoxy. Due to fiber orientations an orthotropic case and a monoclinic symmetry of the material are considered. Results are demonstrated by first 20 dispersion curves and shapes of the waves for the chosen wave-length. The possibilities (or the properties) of both approaches are demonstrated by the tables and the figures presented.
A Novel Method to Measure Residual Stresses in Laminated Composites
Authors: Ifju Peter G. , Kilday Brian C. , Niu Xiaokai , Liu Shao-Chun
Published: April 2011

A non-destructive method, called the Cure Referencing Method (CRM), was developed to measure the residual stresses in laminated composites. The method incorporates the use of moiré interferometry (a laser based optical method) and replication of diffraction gratings on the surface of laminates in the autoclave during cure. This allows the strains due to resin shrinkage and thermal expansion to be referenced back to the stress free state. For thermoset matrix composites, the stress free state exists just prior to matrix solidification. To determine the residual stress in multidirectional laminates, the strain difference from cure temperature to room temperature was first measured. Then, by doing the same for a unidirectional panel, that was cured simultaneously with the multidirectional laminate, the free thermal expansion of the unidirectional lamina could be defined for the multidirectional case. Using laminate theory, the residual stresses in each ply of the multidirectional laminate were calculated accordingly. The method was evaluated by measuring the residual stresses in balanced symmetric cross-ply, unbalanced symmetric cross-ply and symmetric angle-ply AS4/3501-6 graphite/epoxy laminates. To determine the repeatability of the method, five separate autoclave runs were performed, each with the three multidirectional panels, and the unidirectional panel.
Failures at Attachment Holes in Brittle Matrix Laminates
Authors: Genin Guy M. , Hutchinson John W.
Published: April 2011

Mechanical attachments for a brittle-matrix fiber-reinforced cross-ply composite are analyzed. Two model problems are considered: first, a bolt-loaded strut, and second, an infinitely-wide plate with evenly-spaced bolts. The possible failure mechanisms for the strut are identified, and the influence of bolt size, bolt location, bolt elasticity, and interfacial friction on these failure mechanisms and the associated failure loads are evaluated. The bolt spacing for the plate is identified that best takes advantage of a SiC/MAS cross-ply's ability to redistribute stresses through the mechanism of matrix cracking.

Boundary value problems are solved using the finite element method. The cross-ply's constitutive behavior is described by the model of Genin and Hutchinson [1].
Accelerated Curing of Adhesives in Bonded Joints by Induction Heating
Authors: Tay T. E. , Fink B. K. , McKnight S. H. , Yarlagadda S. , Gillespie J. W.
Published: April 2011

This paper presents the results of a study on the use of induction heating for rapid curing of a commercially available room-temperature curing paste adhesive, with a view to application in the repair of composite structures. The repair of damaged composite structures using adhesively bonded patches is often a very time-consuming process. This is partly due to the long times required for complete and satisfactory cure of the adhesive systems used. While the curing process can be accelerated by application of heat through devices such as heating blankets and lamps, these methods are inefficient since considerable heat is lost to the surrounding material and environment. The method of electromagnetic heating, however, is well suited for rapid and localized heating of the adhesive bondline provided suitable susceptors are used. In this paper, it is shown that induction heating can be successfully used to cure a room-temperature curing paste adhesive. Furthermore, results of single lap shear and double notched shear specimen tests show no substantial reduction in the strength of bonded joints with the use of embedded susceptors.
Macroscopic and Microscopic Elastic Constant Measurements of Ceramic Matrix Composites Using Ultrasonic Waves
Authors: Okabe Yoji , Takeda Nobuo , Sekiguchi Minoru
Published: April 2011

This paper presents the results of elastic constant determination of Ceramic Matrix Composites (CMC) using two types of ultrasonic measurement systems, and shows the possibility of the elastic constants determination for transversely isotropic materials not only in a macroscopic area but also in a microscopic one at the order of 1 mm. Macroscopic elastic constants were determined from the transmitted wave velocities measured by a double-through-transmission method. Microscopic elastic constants were inverted from the reflection coefficients at a small spot on the surface, which were measured using an ultrasonic micro-spectrometer. The inversion from the reflection coefficients was tried by two ways of analysis: (1) fitting to phase curves of reflection coefficients; (2) fitting to surface wave velocity dispersion. By comparison between these values and those measured by tensile tests, it was conformed that all elastic constants of a unidirectional CMC could be determined by ultrasonic waves appropriately not only in a macroscopic area but also in a microscopic one.
Fiber-Optic and Ultrasonic Measurements for In-Situ Cure Monitoring of Graphite/Epoxy Composites
Authors: Chen J. -Y. , Hoa S. V. , Jen C. -K. , Wang H.
Published: April 2011

To produce high-quality composites with high density and low void content, the knowledge of cure process is very important, and the sensors capable of monitoring the cure process are therefore desirable.

Since the term of "fully processed" should be a reflection of the ultimate material application, the objectives of the present work are to monitor how material properties have been developed during the cure and justify when "end-of-cure" has been achieved by measuring chemical and mechanical properties of the curing composites. As a reference, differential scanning calorimetry is used to evaluate the degree of cure while fiber-optic sensors are used to measure the evolution of process-induced strains, and ultrasonic sensors are used to monitor the development of viscoelastic properties of the curing composites. Moreover, an ultrasonic cure monitoring system has been developed, by using conventional broadband ultrasonic sensors together with clad buffer rods. The major merits of this system can be summarized as (i) workable inside an autoclave at high temperature (for example, up to 2500C if by water-cooling) and internal pressure (for example, 100 psi); (ii) high signal to spurious ultrasonic noise ratio, and high signal strength; (iii) suitable for longitudinal or shear wave measurement in reflection/transmission mode.
Direct Measurement of Invariant Mechanical Parameters of Composite Plates
Authors: Grédiac M. , Fournier N. , Paris P. -A. , Surrel Y.
Published: April 2011

This paper deals with the direct measurement of invariant parameters describing the intrinsic elastic response of anisotropic composite plates in bending. Theoretical results giving the link between the unknown parameters and the strain field on the top surface of a plate subjected to two different bending tests are given first. The experimental setup is then described. The invariant nature of the measured parameters is finally verified through an example. As a conclusion, it is shown that the invariant combinations of anisotropic plates compliances can be directly measured using a suitable strategy.
Inverse Expression of Peroxisomes and Connexin-43 in the Granulosa Cells of the Quail Follicle
Authors: Farioli-Vecchioli Stefano , Raes Stefaan , Espeel Marc , Roels Frank , D'Herde Katharina
Published: April 2011

Studying the regulation of peroxisome (Px) expression could improve our understanding of human peroxisomal disorders. The granulosa of the largest preovulatory quail follicles proved to be a relevant model because (a) Px expression changes according to the follicular maturation stage and (b) Px expression varies regionally according to the distance of the granulosa relative to the germinal disc region containing the female gamete (oocyte). The question was asked whether Px expression is related to the extent of metabolic cell coupling and whether zonal Px variation is causally related to oocytal factors. This was evaluated by the presence of catalase and Cx-43 (marker proteins for peroxisomes and gap junctions, respectively) and by in vitro experiments with granulosa explants. The data obtained show that the expression of Cx-43 and Px is inversely correlated both temporally and spatially. Uncoupling of gap junctions results in an upregulation of α-catalase immunofluorescence. This is in agreement with reports that gap junctions are often negatively affected by Px proliferators. The zonal gradient in Px expression appears to be imposed by the oocyte, as is the case for steroidogenesis and proliferative capacity in the granulosa epithelium.
cAMP-dependent Cl- Channel Protein (CFTR) and Its mRNA Are Expressed in the Secretory Portion of Human Eccrine Sweat Gland
Authors: Sato Fusako , Sato Kenzo
Published: April 2011

Immunoreactive cystic fibrosis transport regulator (CFTR) proteins in human sweat ducts has been documented but CFTR expression in the secretory coil has remained uncertain. Using monoclonal antibodies (MAbs) against epitopes in the R-domain and C-terminus, we observed the following: Formalin fixation masks the CFTR epitopes but the epitopes are exposed by treatment with urea and heat (antigen retrieval). Pen-Fix fixation preserves CFTR epitopes. The secretory coil also expresses CFTR epitopes for the R-domain and C-terminus. An MAb against C-terminus amino acids 1466-1480 coupled to keyhole limpet hemocyanin (MAb WC) stained dark cells predominantly. Staining by MAbs against the C-terminus was completely blocked by a C-terminus peptide. mRNA for CFTR was amplified by RT-PCR in both the duct and the secretory coil. In situ hybridization for CFTR mRNA after 3SR amplification indicates that mRNA is localized in the dark cells and perhaps also in the clear cell cytoplasm near the secretory coil. mRNA is present in both the luminal and basal duct cells. We conclude that CFTR is expressed equally well in both the duct and the secretory coil, suggesting that cAMP-dependent Cl- channels are involved in regulation of sweat secretion and duct absorption.
Fatty Acid Synthase Is Expressed Mainly in Adult Hormone-sensitive Cells or Cells with High Lipid Metabolism and in Proliferating Fetal Cells1
Authors: Kusakabe Takashi , Maeda Masahiro , Hoshi Nobuo , Sugino Takashi , Watanabe Kazuo , Fukuda Takeaki , Suzuki Toshimitsu
Published: April 2011

SUMMARY Animal fatty acid synthase (FAS) is a homodimer protein which synthesizes long-chain fatty acids and is rich in liver, brain, breast, and lung. However, the precise cellular localization of FAS in human tissues has not been elucidated. Immunohistochemistry with a new antibody to human FAS revealed that in adult human tissues FAS is distributed mainly in cells with high lipid metabolism (adipocytes, corpus luteum, hepatocytes, sebaceous glands, and Type II alveolar cells), in hormone-sensitive cells (anterior pituitary, apocrine gland, breast, endometrium, prostate, seminal vesicle, and adrenal cortex), and in a subset of epithelial cells of duodenum and stomach, colon absorptive cells, cerebral neurons, basket cells of cerebellum, decidua, uroepithelium, and epidymis. In fetal cells at 20 weeks of gestation, FAS was mainly present in proliferative epithelial cells of the digestive and respiratory systems, proximal renal tubules, adrenocortical cells, and mesenchymal and hematolymphoid cells. Staining was significant in nonproliferating cells, as observed in adult, and in sympathetic ganglion cells, Leidig cells of testis, and Langhans cells of chorionic villi. FAS is maintained in hormone-sensitive cells and/or cells active in lipid metabolism in the adult and is expressed in proliferating cells in the fetus, suggesting active fatty acid synthesis for energy utilization or membrane lipids.
A New Method to Visualize the Helicobacter pylori-associated Lewisb-binding Adhesin Utilizing SDS-digested Freeze-fracture Replica Labeling
Authors: Petersson Christoffer , Larsson Bertil , Mahdavi Jafar , Borén Thomas , Magnusson Karl-Eric
Published: April 2011

Freeze-fracture replica labeling has become a versatile tool to visualize both membrane components and other cell structures using SDS-replica cleaning before specific immunogold labeling of proteins or lipids. We report here for the first time the adoption and optimization of the method to studies of bacterial envelopes, as applied to structural analysis of the distribution of the unique BabA-adhesin of the gastric pathogen Helicobacter pylori. BabA is important for bacterial adherence to the human epithelial cell lining of the stomach. The adhesin was found to be distributed all over the bacterial cell surfaces. Our results suggest that the SDS-replica labeling allows assessment of protein localization to distinct cell compartments and analysis of co-localization with neighboring membrane structures.
Lectin Histochemistry of the Spleen: A New Lectin Visualizes the Stromal Architecture of White Pulp and the Sinuses of Red Pulp
Authors: Düllmann Jochen , Feldhaus Susanne , Damme Els J. M. Van , Peumans Willy J. , Schumacher Udo
Published: April 2011

The subcompartmentalization of the white pulp in the spleen is the result of interactions of specific resident stromal cells and migrating subtypes of lymphocytes. Because carbohydrate residues of cell membranes and extracellular matrices are involved in cell–cell and cell–matrix interactions, they were investigated in rat spleen by a broad panel of lectins. Splenic macrophages, which were also demonstrated by Perls' Prussian blue reaction, were labeled selectively by most mannose-specific lectins and gave the characteristic distribution patterns in all splenic (sub)compartments. One recently isolated lectin, Chelidonium majus agglutinin (CMA), visualized predominantly central arterioles, the reticular meshwork (RM) in the periarteriolar lymphatic sheaths (PALS), the circumferential reticulum cells limiting PALS and follicles, and some follicular dendritic cells (FDCs) in white pulp. The endothelial cells of venous sinuses in red pulp were also labeled by CMA and, if frozen sections were used, CMA also labeled the macrophages of the red pulp. Compared to CMA, the monoclonal antibody CD11, which can be used only in frozen sections, stained almost solely the fibrous (extracellular) component of the RM. Because CMA stains the reticulum cells in particular, it is better suited to visualize the stromal architecture of splenic white pulp than the monoclonal antibody. Because CMA can be applied to paraffin-embedded material, it is a particularly useful tool to study the splenic stromal architecture in archival material.
Age-related Alterations in IL-1β, TNF-α, and IL-6 Concentrations in Parotid Acinar Cells from BALB/c and Non-obese Diabetic Mice
Authors: Yamakawa Midori , Weinstein Robert , Tsuji Takanori , McBride Jim , Wong David T. W. , Login Gary R.
Published: April 2011

IL-1β, TNF-α, and IL-6 have been implicated in the destruction of parotid gland acinar cells (but not duct cells) in autoimmune sialoadenitis. Here we report the temporal alterations of these cytokines in parotid acinar cells that may lead to this specificity in cell death in the non-obese diabetic (NOD) mouse model for Sjögren's syndrome. Immunohistochemistry on paraffin sections of parotid gland from 5- and 10-week-old BALB/c and NOD mice confirmed the presence of many peri-acinar lymphoid nodules but few T-cells and macrophages between acinar cells. RT-PCR on enzymatically dispersed mouse parotid acinar cells (MPACs) showed no bands for CD3∊, CD20, or F4/80 regardless of mouse strain or age. By ELISA, MPACs from 10-week-old NODs showed a small but highly significant ( p < 0.003) increase in IL-1β and a large significant decrease ( p < 0.008) in IL-6 compared to 5-week-old NODs. Norepinephrine-stimulated amylase release from MPACs was not different regardless of mouse strain or age. These data show that alterations in acinar cell production of IL-1β and IL-6 in aging NODs precede periductal lymphoid aggregates and acinar cell secretory dysfunction. (J Histochem Cytochem 48:1033–1041, 2000)
Cathepsin A Is Expressed in a Cell- and Region-specific Manner in the Testis and Epididymis and Is Not Regulated by Testicular or Pituitary Factors
Authors: Luedtke Chad C. , Andonian Sero , Igdoura Suleiman , Hermo Louis
Published: April 2011

The epithelial cells of the testis are involved in the production, differentiation, and sustenance of sperm, and those of the epididymis play a major role in sperm maturation, protection, and storage. These tissues express various proteins that respond differently to androgens. Cathepsin A is a multifunctional lysosomal carboxypeptidase that also functions as a protective and an activator protein for neuraminidase and β-galactosidase. In this study, cathepsin A was immunolocalized by light and electron microscopy using a polyclonal affinity-purified antibody on the testis and epididymis of normal, orchidectomized with or without testosterone supplementation, efferent duct-ligated, and hypophysectomized adult rats. In normal rats, cathepsin A expression was noted in lysosomes of Sertoli and Leydig cells but not in germ cells of the testis, as well as nonciliated cells of the efferent ducts. In the epididymis, a cell- and region-specific distribution of cathepsin A was noted. In experimentally treated animals, no changes were noted in the expression of cathepsin A. Immunolabeling of tissues examined at the electron microscopic level revealed that lysosomes were reactive. These data indicate cell- and region-specific expression of cathepsin A in cells of the testis and epididymis and also indicate that cathepsin A expression is not regulated by testicular or pituitary factors. (J Histochem Cytochem 48:1131–1146, 2000)
Differentiation of Necrotic Cell Death With or Without Lysosomal Activation: Application of Acute Liver Injury Models Induced by Carbon Tetrachloride (CCL4) and Dimethylnitrosamine (DMN)
Authors: Yasuda Masanori , Okabe Tsuyoshi , Itoh Johbu , Takekoshi Susumu , Hasegawa Hideaki , Nagata Hidetaka , Osamura R. Yoshiyuki , Watanabe Keiichi
Published: April 2011

We investigated the relationship between DNA degradation and lysosome activity (loss of lysosomal integrity) in necrotic cell death induced by carbon tetrachloride (CCl4) and dimethylnitrosamine (DMN): coagulation necrosis and hemorrhagic necrosis, respectively. TdT-mediated dUTP–biotin nick end-labeling (TUNEL) and enzyme histochemistry for acid phosphatase were performed in both models and results were analyzed by light microscopy, electron microscopy, and confocal laser scanning microscopy (CLSM). In the CCl4-injected liver, TUNEL staining was closely associated with release of lysosomal enzymes into the cytoplasm, and intranuclear deposition of lysosomal enzymes took place at an early stage of subcellular damage. In the DMN-injected liver, TUNEL-positive nuclei tended to have well-preserved lysosomes and centrally localized TUNEL signals. It was assumed that acute hepatocellular damage in the CCl4-injected liver would be characterized by necrotic cell death with lysosome activation and that damage in the DMN-injected liver would be necrotic cell death without lysosome activation. In the DMN-injected liver, DNA degradation may be selectively induced in the nuclear center, in which heterochromatin (including inactive chromatin) is believed to be a target. We concluded that necrotic cell death, i.e., DNA degradation, would be at least divided into two types, with/without association with lysosome activation, represented by necrotic cell death in the CCl4-injected liver and that in the DMN-injected liver.
Quantitation of Plasma Membrane Expression of a Fusion Protein of Na/H Exchanger NHE3 and Green Fluorescence Protein (GFP) in Living PS120 Fibroblasts
Authors: Janecki Andrzej J. , Janecki Maria , Akhter Shafinaz , Donowitz Mark
Published: April 2011

We developed a confocal morphometric analysis to quantitate the relative plasma membrane (PM) expression of the Na/H exchanger NHE3 in living PS120 fibroblasts. NHE3 is a membrane transport protein that is acutely regulated by changes in the number of molecules expressed at the PM. To quantitate the PM expression of NHE3 under various experimental conditions, we stably expressed a chimera of rabbit NHE3 and green fluorescent protein (NHE3–GFP) in PS120 fibroblasts. A three-dimensional (3D) map of the intracellular distribution of NHE3–GFP was obtained by confocal laser scanning microscopy (CLSM) of cells superfused with a styryl dye, FM 4–64. This fluorophore rapidly and reversibly labeled the outer lipid layer of the PM, which allowed generation of a digital mask of the PM and calculation of the fraction of a total cellular NHE3–GFP expressed at the PM. This analysis was successfully used to quantitate the relative PM expression of NHE3–GFP in control cells (25%) and a decrease in the expression caused by subsequent exposure of cells to wortmannin (5.1%). Reliability of the method was confirmed by cell surface biotinylation, which yielded very similar results. Confocal morphometric analysis is fast and reproducible and could potentially be used for investigations on regulation of expression of other membrane proteins.
Localization of Transcription Factor AP-1 Family Proteins in Ameloblast Nuclei of the Rat Incisor
Authors: Nishikawa Sumio
Published: April 2011

We examined by immunocytochemistry the localization of the AP-1 family proteins c-Jun, JunB, JunD, c-Fos, FosB, Fra-1, and Fra-2 in rat incisor ameloblasts. Most of the antibodies against AP-1 family proteins, except for c-Fos-specific antibody, labeled ameloblast nuclei. The labeling intensity of the c-Jun, JunD, and Fra-2 antibodies was stronger than that of JunB, FosB, and Fra-1. Antibody reactivities of c-Jun, JunD, and Fra-2 were greatly enhanced during or after the transition zone. Furthermore, c-Jun antibodies labeled maturation ameloblasts in a cyclic pattern, which was correlated with ameloblast modulation. Disruption of ameloblast modulation by colchicine injection resulted in greatly decreased reactivity of the c-Jun antibody in the ameloblast nuclei of the maturation zone. Phospho-specific antibodies to c-Jun labeled ameloblast nuclei only weakly throughout the secretion, transition, and maturation zones. These results suggest that the stage-specific localization of AP-1 in ameloblasts is closely related to tooth enamel formation.
A New Rapid Immunohistochemical Staining Technique Using the EnVision Antibody Complex
Authors: Kämmerer Ulrike , Kapp Michaela , Gassel Andrea Maria , Richter Thomas , Tank Christian , Dietl Johannes , Ruck Peter
Published: April 2011

Rapid immunohistochemical investigation, in addition to staining with hematoxylin and eosin, would be useful during intraoperative frozen section diagnosis in some cases. This study was undertaken to investigate whether the recently described EnVision system, a highly sensitive two-step immunohistochemical technique, could be modified for rapid immunostaining of frozen sections. Forty-five primary antibodies were tested on frozen sections from various different tissues. After fixation in acetone for 1 min and air-drying, the sections were incubated for 3 min each with the primary antibody, the EnVision complex (a large number of secondary antibodies and horseradish peroxidase coupled to a dextran backbone), and the chromogen (3,3′diaminobenzidine or 3-amino-9-ethylcarbazole). All reactions were carried out at 37C. Specific staining was seen with 38 antibodies (including HMB-45 and antibodies against keratin, vimentin, leukocyte common antigen, smooth muscle actin, synaptophysin, CD34, CD3, CD20, and prostate-specific antigen). A modification of the EnVision method allows the detection of a broad spectrum of antigens in frozen sections in less than 13 min. This method could be a useful new tool in frozen section diagnosis and research.

(J Histochem Cytochem 49:623–630, 2001)
Extrahepatic Expression of Apolipoprotein A-II in Mouse Tissues: Possible Contribution to Mouse Senile Amyloidosis
Authors: Fu Li , Matsuyama Ikuo , Chiba Takuya , Xing Yanming , Korenaga Tatsumi , Guo Zhanjun , Fu Xiaoying , Nakayama Jun , Mori Masayuki , Higuchi Keiichi
Published: April 2011

Apolipoprotein A-II (apoA-II), an apolipoprotein in serum high-density lipoprotein, is a precursor of mouse senile amyloid fibrils. The liver has been considered to be the primary site of synthesis. However, we performed nonradioactive in situ hybridization analysis in tissue sections from young and old amyloidogenic (R1.P1- Apoa2 c ) and amyloid-resistant (SAMR1) mice and revealed that other tissues in addition to the liver synthesize apoA-II. We found a strong hybridization signal in the basal cells of the squamous epithelium and the chief cells of the fundic gland in the stomach, the crypt cells and a small portion of the absorptive epithelial cells in the small intestine, the basal cells of the tongue mucosa, and the basal cells of the epidermis and hair follicles in the skin in both mouse strains. Expression of apoA-II mRNA in those tissues was also examined by RT-PCR analysis. Immunolocalization of apoA-II protein also indicated the cellular localization of apoA-II. ApoA-II transcription was not observed in the heart. Amyloid deposition was observed around the cells expressing apoA-II mRNA in the old R1.P1- Apoa2 c mice. These results demonstrate that the apoA-II mRNA is transcribed and translated in various extrahepatic tissues and suggest a possible contribution of apoA-II synthesized in these tissues to amyloid deposition.
Immunohistochemical Localization and Comparison of Carboxypeptidases D, E, and Z, α-MSH, ACTH, and MIB-1 Between Human Anterior and Corticotroph Cell “Basophil Invasion” of the Posterior Pituitary
Authors: Fan Xuemo , Olson Sandy J. , Johnson Mahlon D.
Published: April 2011

Basophil invasion, i.e., invasion of basophilic corticotrophs from the residual intermediate lobe into the posterior lobe of the human pituitary gland, is believed to be a physiological phenomenon. This study evaluated the distribution of CPE, CPD, CPZ, α-MSH, ACTH, and Ki-67 immunoreactivity between human anterior pituitary and basophil invasion of the neurohypophysis. Mild to moderate immunoreactivities for CPE and CPZ were distributed relatively uniformly in the majority of the anterior pituitary cells and basophil invasion. In contrast, only corticotrophs exhibited intense CPD immunoreactivity. Basophil invasion showed similar immunoreactivities for α-MSH, ACTH, CPE, and CPZ as corticotrophs in the anterior pituitary, except for CPD, which was detected much less frequently. In the posterior lobe, CPE, CPD, and CPZ were present within the Herring bodies. Although no MIB-1 immunoreactivity was identified in anterior pituitary cells, limited MIB-1 labeling was detected in basophil invasion in five of ten cases. Highly selective expression of CPD in corticotrophs suggests that CPD plays a particularly important role in prohormone (POMC) processing in corticotrophs, with minimal or no significant roles in non-corticotrophs. Evidence that corticotrophs in basophil invasion are undergoing proliferation and are also phenotypically different from their counterpart in the anterior pituitary has further raised the possibility of some neoplastic potential.
The Presence of v-abl-transformed V3 Mast Cells in the Lungs Augments Pulmonary Vascular Permeability to Acid Aspiration
Authors: Mukundan Chandrika , Gurish Michael F. , Austen K. Frank , Hechtman Herbert B. , Friend Daniel S.
Published: April 2011

Acid aspiration causes pulmonary vascular permeability and PMN sequestration. By increasing pulmonary mast cells through adoptive transfer of v-abl-transformed mast cells (V3MCs) into BALB/c mice, we now show that the greater mast cell number in the lung is associated with increased pulmonary injury.
Evidence for Endoreduplication: Germ Cell DNA Levels Prior to Chromatin Diminution in Mesocyclops edax
Authors: Rasch Ellen M. , Wyngaard Grace A.
Published: April 2011

We studied the functional significance of marked differences in the DNA content of somatic cells and germ line nuclei by static Feulgen–DNA cytophotometry for several species of microcrustaceans that exhibit chromatin diminution during very early stages of embryogenesis. Mature females and males showed many gonadal nuclei with elevated amounts of DNA that persist until dispersal of this “extra” DNA throughout the cytoplasm as fragments and coalescing droplets of chromatin during anaphase of the diminution division.
A Novel Method for Simultaneous Anterograde and Retrograde Labeling of Spinal Cord Motor Tracts in the Same Animal
Authors: Tsai Eve C. , van Bendegem Rita L. , Hwang Steven W. , Tator Charles H.
Published: April 2011

Examination of repaired spinal cord tracts has usually required separate groups of animals for anterograde and retrograde tracing owing to the incompatibility of techniques such as tissue fixation. However, anterograde and retrograde labeling of different animals subjected to the same repair may not allow accurate examination of that repair strategy because widely variable results can occur in animals subjected to the same strategy. We have developed a reliable method of labeling spinal cord motor tracts bidirectionally in the same animal using DiI, a lipophilic dye, to anterogradely label the corticospinal tract and Fluoro-Gold (FG) to retrogradely label cortical and brainstem neurons of several spinal cord motor tracts in normal and injured adult rats. Other tracer combinations (lipophilic dyes or fluorescent dextrans) were also investigated but were less effective. We also developed methods to minimize autofluorescence with the DiI/FG technique, and found that the DiI/FG technique is compatible with decalcification and immunohistochemistry for several markers relevant for studies of spinal cord regeneration. Thus, the use of anterograde DiI and retrograde FG is a novel technique for bidirectional labeling of the motor tracts of the adult spinal cord with fluorescent tracers and should be useful for demonstrating neurite regeneration in studies of spinal cord repair. (J Histochem Cytochem 49:1111–1122, 2001)
ADAM-10 Protein Is Present in Human Articular Cartilage Primarily in the Membrane-bound Form and Is Upregulated in Osteoarthritis and in Response to IL-1α in Bovine Nasal Cartilage
Authors: Chubinskaya Susan , Mikhail Rita , Deutsch Angela , Tindal Michael H.
Published: April 2011

The objective of our study was to determine the tissue distribution and localization of ADAM-10 protein in human and bovine cartilage and the changes it undergoes with cartilage degeneration seen in osteoarthritis (OA) and under the influence of interleukin-1 (IL-1). Human normal and OA articular cartilage and bovine nasal cartilage cultured in the presence of IL-1α were processed for histology and immunohistochemistry. ADAM-10 protein was extracted from human cartilage and analyzed by Western blotting using anti-ADAM-10 antibodies. Fluor S Image analyzer and Quantity One software program were applied to quantify the total amount of ADAM-10. ADAM-10 protein was detected in both human and bovine cartilage. The strongest immunostaining was found in the cytoplasm and/or cell membranes of the superficial and upper middle layer of normal adult human cartilage, in the clusters and fibrillated areas of OA cartilage, and in IL-1α-stimulated bovine nasal cartilage. The distribution of ADAM-10 protein in bovine nasal cartilage was dependent on the length of exposure to IL-1 α and corresponded to the areas of proteoglycan depletion. By Western blotting analysis of human cartilage, ADAM-10 was primarily detected in the membrane-enriched fraction and its levels were increased in degenerated and OA cartilage compared to normal cartilage. The results of this study suggest that ADAM-10 might be an important factor associated with cartilage degenerative processes. (J Histochem Cytochem 49:1165–1176, 2001)
Distribution of the Muscarinic K+ Channel Proteins Kir3.1 and Kir3.4 in the Ventricle, Atrium, and Sinoatrial Node of Heart
Authors: Dobrzynski Halina , Marples David D.R. , Musa Hanny , Yamanushi Tomoko T. , Hendersonxyl Zaineb , Takagishi Yoshiko , Honjo Haruo , Kodama Itsuo , Boyett Mark R.
Published: April 2011

The functionally important effects on the heart of ACh released from vagal nerves are principally mediated by the muscarinic K+ channel. The aim of this study was to determine the abundance and cellular location of the muscarinic K+ channel subunits Kir3.1 and Kir3.4 in different regions of heart. Western blotting showed a very low abundance of Kir3.1 in rat ventricle, although Kir3.1 was undetectable in guinea pig and ferret ventricle. Although immunofluorescence on tissue sections showed no labeling of Kir3.1 in rat, guinea pig, and ferret ventricle and Kir3.4 in rat ventricle, immunofluorescence on single ventricular cells from rat showed labeling in t-tubules of both Kir3.1 and Kir3.4. Kir3.1 was abundant in the atrium of the three species, as shown by Western blotting and immunofluorescence, and Kir3.4 was abundant in the atrium of rat, as shown by immunofluorescence. Immunofluorescence showed Kir3.1 expression in SA node from the three species and Kir3.4 expression in the SA node from rat. The muscarinic K+ channel is activated by ACh via the m2 muscarinic receptor and, in atrium and SA node from ferret, Kir3.1 labeling was co-localized with m2 muscarinic receptor labeling throughout the outer cell membrane.
The Spectrum of Human Kallikrein 6 (Zyme/Protease M/Neurosin) Expression in Human Tissues as Assessed by Immunohistochemistry
Authors: Petraki Constantina D. , Karavana Vassiliki N. , Skoufogiannis Pavlos T. , Little Sheila P. , Howarth David J.C. , Yousef George M. , Diamandis Eleftherios P.
Published: April 2011

The KLK6 gene is a new member of the human kallikrein gene family and encodes for a secreted protease, human kallikrein 6 (hK6; also known as zyme/protease M/neurosin). No study has as yet reported detailed immunohistochemical localization of hK6 in human tissues. Our purpose was to examine the expression of hK6 in human tissues by immunohistochemistry. We have analyzed 199 paraffin blocks from archival, current, and autopsy material prepared from almost every normal human tissue. We employed an hK6-specific polyclonal rabbit antibody and avidin-biotin to localize hK6 by IHC. The staining pattern, the distribution of the immunostaining, and its intensity were studied in detail. The IHC expression of zyme was generally cytoplasmic. Various normal human tissues expressed the protein abundantly. Glandular epithelia constituted the main immunoexpression sites, with representative organs being the breast, prostate, kidney, endometrium, colon, appendix, salivary glands, bile ducts, and gallbladder. The small intestine, stomach, endocervix, Fallopian tube, epididymis, bronchus, and upper respiratory tract showed a focal expression as well. Choroid plexus epithelium, peripheral nerves, and some neuroendocrine cells (including the islets of Langerhans, cells in the anterior pituitary gland, and adrenal medulla) expressed the protein strongly and diffusely. A characteristic immunostaining was observed in the Hassall's corpuscles of the thymus, the oxyphilic cells of the thyroid and parathyroid glands, the primordial follicles of the ovary, dendritic cells mainly in the spleen, and in various cells of the placenta.
Tissue Distribution and Cell Type-specific Expression of p120ctn Isoforms
Authors: Montonen Outi , Aho Mikko , Uitto Jouni , Aho Sirpa
Published: April 2011

Cadherin-based molecular complexes play a major role in cell-cell adhesion. At the adherens junctions the intracellular domain of cadherins specifically interacts with β-catenin and p120ctn, members of the Armadillo repeat protein family. Differential splicing and utilization of the alternative translation initiation codons lead to many p120ctn isoforms. Two major p120ctn isoforms are expressed in mouse tissues. In this study we used indirect immunofluorescence to demonstrate significant tissue specificity in expression of the p120ctn isoforms. The short isoform is abundant at cell-cell adhesion junctions in epidermis, palatal, and tongue epithelia, in the ducts of excretory glands, bronchiolar epithelium, and in mucosal epithelia of esophagus, forestomach, and small intestine. In contrast, the long isoform, containing an amino terminus highly conserved within the p120ctn subfamily, is expressed at vascular-endothelial cell junctions in blood vessels, at cell-cell junctions in the serosal epithelium lining the internal organs, in choroid plexus of brain, in the pigment epithelium of retina, and in structures such as the outer limiting membrane of retina and intercalated discs of cardiomyocytes. The tissue- and cell type-specific expression of p120ctn isoforms suggests a role for the long p120ctn isoform in cell structures responsible for stable tissue integrity, compared to the role of the short isoform in cell-cell adhesion in the external epithelia with rapid turnover.