bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood barriers of the epididymis and vas deferens act asynchronously with the blood barrier of the testis in the mink (Mustela vison)
Authors: Pelletier R.‐Marc
Published: February 2005

The purpose of the present study was to determine whether the blood barrier of the epididymis and vas deferens acted synchronously or not with the blood barrier of the testis. The permeability of the blood‐epididymis and blood‐vas deferens barrier was tested in neonatal kit mink up to puberty and monthly in adult minks throughout the annual seasonal reproductive cycle. Attention was focused particularly on time intevals when the blood barrier of the testis has been documented to be permeable, namely, before puberty and during testicular regression in the adult. One of two electron‐opaque permeability tracers was perfused into the blood stream: horeseradish peroxidase (HRP) or lanthanum nitrate. The convoluted tube of the epididymis was divided into three anatomical regions: the caput, corpus, and cauda. The vas deferens was divided into proximal and distal regions. At birth and throughout puberty, the three regions of the epididymis and the two of the vas deferens showed a lumen and a competent blood barrier. In the adult, a lumen persisted in the epididymis and vas deferens throughout the annual seasonal reproductive cycle, and the blood barrier of the excurrent duct remained impermeable even when the blood barrier in the testis become momentarily permeable during testicular regression. When HRP was used to test the permeability of the blood‐tissue barrier of the excurrent ducts, no tracer deposits were observed on the lumenal surface of the epithelium. Conversely, when lanthanum served as the tracer, deposits of the probe were associated with microvilli and intracellular membranes despite impermeability of tight junctions. The data show that the lanthanum technique can yield false‐positive results. The findings also indicate that (1) a blood‐excurrent duct barrier is established before the blood‐testis barrier and (2) the two barriers act asynchronously. It is therefore plausible that they are modulated by distinct factors. © 1994 Wiley‐Liss, Inc.
An introduction to biomimetics: A structural viewpoint
Authors: Sarikaya Mehmet
Published: February 2005

Biomimetics is a newly emerging interdisciplinary field in materials science and engineering and biology in which lesson learned from biology form the basis for novel technological materials. It involves investigation of both structures and physical functions of biological composites of engineering interest with the goal of designing and synthesizing new and improved materials. This paper discusses microarchitectural aspects of some structural biocomposites, presents microstructural criteria for future materials design and processing, and identifies areas of future research. © 1994 Wiley‐Liss, Inc.
Molecular‐weight factors affecting formation of the OBDD morphology in block copolymer blends
Authors: Spontak Richard J. , Smith Steven D. , Ashraf Arman
Published: February 2005

Block copolymers undergo self‐organization when the blocks are sufficiently incompatible, and generate a variety of periodic morphologies in the limit of strong segregation. An equilibrium morphology only recently added to the diblock copolymer phase diagram is the ordered bicontinuous double‐diamond (OBDD) morphology, which possesses a Pn3m space group. It has been observed over a very narrow composition range (ca. 4 vol%), thereby making it difficult to obtain in pure copolymers. This obstacle can, however, be surmounted by blending a copolymer with one of the parent homopolymers. In the present study, several symmetric poly(styrene‐b‐isoprene) diblock copolymers varying in molecular weight (M) have been blended with homopolystyrene to produce the OBDD morphology. Transmission electron microscopy is employed here to identify the morphologies in cryosections of each blend and reveals that, at intermediate molecular weights, the OBDD morphology is indeed observed. At low M, near the order‐disorder transition, however, a lamellar catenoid or disordered morphology is preferred. At the other extreme, high‐M blends are frustrated by molecular entanglements and adopt a cylindrical morphology. © 1994 Wiley‐Liss, Inc.
Insight into the regulation by second messenger molecules of the permeability of the blood‐brain barrier
Authors: Joó Ferenc
Published: February 2005

Recent advances in our knowledge of the blood‐brain barrier have in part been made by studying the properties and function of cerebral endothelial cells in vitro. After an era of working with a fraction, enriched in cerebral microvessels by centrifugation, the next generation of in vitro blood‐brain barrier model systems was introduced, when the conditions for routinely culturing the endothelial cells were established. This review summarizes the results obtained mainly from this in vitro approach. Different elements of the intracellular signaling messenger systems have been detected in the course of our studies in the cerebral endothelial cells. It has been shown that the synthesizing enzymes of and substrate proteins for the second messenger molecules are present in the cerebral endothelial cells, and their activity and/or amount can change in pathological circumstances, i.e., during the formation of brain oedema. Pharmacological treatments interfering with the second messenger systems proved to be effective in the prevention of brain oedema formation. © 1994 Wiley‐Liss, Inc.
High resolution platinum‐carbon replication of freeze‐dried basement membrane
Authors: Ruben George C. , Yurchenco Peter D.
Published: February 2005

High angle platinum/carbon (Pt/C) replication has proved to be a valuable tool in analyzing basement membrane structure in human amnion, bovine lens capsule, and the Engelbreth‐Holm‐Swarm (EHS) tumor. High resolution replicas for transmission electron microscopy (TEM) have been achieved by depositing 1.0 ± 0.1 nm thick Pt/C films backed with rotary deposited 12.5 ± 2.5 nm thick carbon films. The basement membrane collagen IV network was observed to consist of fine branching filaments containing globular domains intrinsic to the filaments. A second quasi‐regular network is formed by laminin. Unidirectional 45° angle Pt/C replication was used for most of this work. The merits and deficiencies of unidirectional vertical replication (80° angle), unidirectional 45° angle, and 20° low angle rotary replication are discussed. Vertical replication produces the highest resolution replicas and has the potential for revealing the overall pattern of basement membrane structural assembly if basement membrane preparations freeze‐dried in low salt can faithfully maintain their in vivo structure. © 1994 Wiley‐Liss, Inc.
The borderline: Basement membranes and the transition from premalignant to malignant neoplasia
Authors: Bosman Fred T.
Published: February 2005

In this paper, the use of immunohistochemistry for the analysis of basement membrane components and related extracellular matrix proteins in human cancer is reviewed. Basement membranes in cancer are dynamic structures that are constantly degraded but also deposited, in close collaboration between tumor cells and stromal cells. Basement membrane immunohistochemistry, using antibodies against type IV collagen and laminin, appears to be a useful tool in the analysis of lesions on the borderline between premalignant and malignant. Basement membrane interruptions, however, cannot be used as the only criterion for the diagnosis of malignancy. Type VII collagen is often degraded prior to type IV collagen and laminin in early invasion. This protein also tends to be expressed in carcinomas when it is not found in the corresponding normal tissue. Tenascin seems to play a complex role in the development of human tumors, including promotion of cell growth and differentiation, cell migration during invasion, and tissue remodeling during the development of primary and metastatic lesions. Further systemic exploration of extracellular matrix molecules in neoplasms should yield new information relevant for cancer biologists and useful in cancer diagnosis. © 1994 Wiley‐Liss, Inc.
Immunogold labelling of leukemic hairy cells with the B‐ly7 monoclonal antibody: An SEM and TEM study
Authors: de Harven Etienne , Christensen Hilary , Poppema Sibrand , Scott J. Gerald
Published: February 2005

Two cases of hairy cell leukemia have been studied by immuno‐TEM and immuno‐SEM after immunogold labelling of the cell surface antigen recognized by the B‐ly7 monoclonal antibody.

Most hairy cells appeared significantly labeled, although the density of the expression of the antigen, as demonstrated by immunogold labelling, seems variable from cell to cell. Moreover, some cells with the morphology of hairy cells and which could not be identified as monocytes were not labeled. Labelling for the antigen identified by the B‐ly7 mAb does not seem to correlate with the presence of ribosome lamellae complexes which were present only in one of the two cases studied. Rare lymphocytes of unidentified lineage were labeled. Monocytes were significantly absent from the samples of peripheral blood of the two patients studied. In one normal control sample, monocytes were observed unlabelled.

The results are discussed in reference to the pathogenesis of hairy cell leukemia, its surprisingly low mitotic rate, and its distinct response to chemotherapy. © 1994 Wiley‐Liss, Inc.
Structure and function of cartilage collagens
Authors: Bruckner Peter , van der Rest Michel
Published: February 2005

Collagens are the major proteinaceous constituents of cartilage. Three collagen types participate in the formation of striated fibrils of cartilage, collagens II, IX, and XI. Collagen II and XI belong to the subgroup of fibrillar collagens and are structurally closely related, differing mainly in their N‐propeptides. Collagen IX has a very different structure but is nevertheless an essential constituent of the striated fibrils. Two other collagen types are also found in cartilage but form distinct structures. Collagen VI, found mainly in the periphery of the chondrocytes, forms beaded filaments. These filaments are probably formed by interaction of collagen VI with hyaluronan. Collagen X is expressed by hypertrophic chondrocytes. It has been shown to form in vitro hexagonal lattices and in vivo to be associated either with striated fibrils or with mats which may correspond to the lattices. The functional role of the collagen diversity in cartilage is discussed. © 1994 Wiley‐Liss, Inc.
Image analysis of the extracellular matrix
Authors: Arsenault A. Larry , Kohler Derek M.
Published: February 2005

The epiphyseal growth plate and articular cartilage matrices were preserved by slam freezing and freeze substitution to optimally retain the native organization for both cellular and matrix components. These specimens were stained and examined using conventional electron microscopic methods. The highly integrated, proteoglycan‐rich matrices were examined by computer image analysis using such parameters as distribution, connectivity, orientation, and a variety of morphometric analyses. Also, different aspects of electron tomography and 3D rendering of matrix vesicles and their associated mineral deposits from epiphyseal growth plates and turkey leg tendons are presented. © 1994 Wiley‐Liss, Inc.
Extraction of second phases from magnesium and aluminum alloys for analytical electron microscopy
Authors: Carpenter G. J. C. , Ng‐Yelim J. , Phaneuf M. W.
Published: February 2005

Techniques are described for the extraction onto carbon replicas of precipitates and inclusions from Mg and Al‐based alloys for analytical transmission electron microscopy. EDX analysis of Mn precipitates from a MG‐Mn alloy illustrates the problems that can arise from spurious X‐rays, caused by the use of a 3mm disc specimen. Published 1994 Wiley‐Liss, Inc.
In situ expression of collagen and proteoglycan genes in notochord and during skeletal development and growth
Authors: Sandell Linda J.
Published: February 2005

Cartilage is an important tissue in skeletogenesis, in the growth of long bones, and as a flexible component of the mature skeleton. The extracellular matrix proteins type II collagen and aggrecan comprise 90% of the matrix and are characteristic of cartilage. Type II collagen provides structural integrity to the tissue, while aggrecan confers resiliency. The quantity of type II procollagen is controlled at the level of transcription of mRNA from the COL2A1 gene. In addition, type II procollagen can be expressed in two isoforms by differential splicing of the primary gene transcript, a post‐transcript, a post‐transcriptional control mechanism. The two mRNAs either include exon 2 (type IIA) or exclude exon 2 (type IIB) which encodes the major portion of the amino (NH2)‐propeptide [Ryan and Sandell (1990), J. Biol. Chem., 265:10334–10339]. The aggrecan gene also encodes alternative splice forms that may be developmentally expressed. The regulation of aggrecan splicing or transcription has not been studied in detail. To determine the spatial and temporal patterns of expression of extracellular matrix in the development of cartilage, we have examined the expression of type II collagen and aggrecan during chondrogenesis in the vertebral column and during elongation of a newborn growth plate. Our results indicate that there is a developmental sequence of type II collagen splice form expression during chondrogenesis with type IIA expressed in prechondrocytes and type IIB expressed in chondrocytes. During elongation of the growth plate, mature chondrocytes express type IIB procollagen and then differentiate into hypertrophic chondrocytes and initiate expression of type X collagen. In all cases, aggrecan was coordinately expressed with type IIB procollagen. As cartilage‐like proteins have been observed in more primitive structures such as notochord, the expression of type II collagen mRNAs was also examined in the notochordal remnants of the vertebral column. In the notochord, the predominant collagen expressed was the type IIA collagen prechondrocyte isoform. Notochordal cells also expressed mRNAs more characteristic of fibroblasts such as versican and decorin: low expression of type I collagen, type IIB collagen, and aggrecan were observed. © 1994 Wiley‐Liss, Inc

This Article is a US Government work and, as such, is in the public domain in the United States of America.

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EBIC study of electron generation function in a‐Si:H
Authors: Najar S. , Equer B.
Published: February 2005

The electron beam induced current technique was used to study electron energy loss in amorphous hydrogenated silicon a‐Si:H. This study leads to the determination of the electron generation function which is needed when using the variable energy electron beam induced current technique (EBIC) analysis of a‐Si:H device. A series of identical n‐i‐p a‐Si:H diodes with a thin aluminium top electodes were fabricated and varying thicknesses of a‐Si:H layer were deposited on it. In EBIC measurements, the n‐i‐p diode was reverse biased at maximum potential. The electron range of a‐Si:H was determined directly by measuring the energy at which the electron beam is completely stopped in the top layer and no carrier generation is possible in the n‐i‐p diode. The generation function is then deduced from EBIC contrast measurements between the aluminium electrode and the top a‐Si:H layer. © 1994 Wiley‐Liss, Inc.
Immunohistochemistry of small intensely fluorescent (SIF) cells and of sif cell‐associated nerve fibers in the rat superior cervical ganglion
Authors: Heym Christine , Klimaschewski Lars , Borghini Nadine , Fischer‐Colbrie Reiner
Published: February 2005

Double‐labelling immunofluorescence was applied on single sections of the rat superior cervical ganglion to evaluate neurochemistry and connectivity of intraganglionic SIF cells. The synaptic vesicle membrane protein synaptophysin and secretoneurin, a newly discovered neuropeptide derived from secretogranin II, proved reliable molecular markers of this cell type, whereas serotonin and tyrosine hydroxylase immunoreactivities were observed in slightly incongruent SIF cell subpopulations. Immunolabelling for vasoactive intestinal polypeptide and neuropeptide Y occurred in few SIF cells. None of the above immunoreactivities were visibly altered by preganglionic or postganglionic denervation, while some SIF cells were immunolabelled for galanin or for the neuronal microtubule‐associated protein MAP2 after postganglionic denervation. SIF cells were nonreactive for the pan‐neuronal marker protein gene product (PGP) 9.5 or neurofilament 160 kD. Intense staining of NADPH‐diaphorase in some SIF cells, suggesting catalytic activity of nitric oxide synthase, could not be substantiated by immunoreactivity for this enzyme. SIF cells were approached by nonidentical fiber populations immunoreactive for PGP 9.5, neurofilament, or neuropeptide Y, whereas immunoreactivities for galanin and vasoactive intestinal polypeptide were colocalized in fiber meshes around SIF cells. The findings indicate (1) neurochemical SIF cell heterogeneity, (2) SIF cell plasticity in response to ganglionic perturbation, and (3) a differentiated innervation of SIF cells in the rat superior cervical ganglion. © 1994 Wiley‐Liss, Inc.
Three‐dimensional imaging and image analysis of hippocampal neurons: Confocal and digitally enhanced wide field microscopy
Authors: Turner James N. , Szarowski Donald H. , Turner Todd J. , Ancin Hakan , Lin Wen‐Chieh , Roysam Badrinath , Holmes Timothy J.
Published: February 2005

The microscopy of biological specimens has traditionally been a two‐dimensional imaging method for analyzing what are in reality three‐dimensional (3‐D) objects. This has been a major limitation of the application of one of science's most widely used tools. Nowhere has this limitation been more acute than in neurobiology, which is dominated by the necessity of understanding both large‐and small‐scale 3‐D anatomy. Fortunately, recent advances in optical instrumentation and computational methods have provided the means for retrieving the third dimension, making full 3‐D microscopic imaging possible. Optical designs have concentrated on the confocal imaging mode while computational methods have made 3‐D imaging possible with wide field microscopes using deconvolution methods. This work presents a brief review of these methods, especially as applied to neurobiology, and data using both approaches. Specimens several hundred micrometers thick can be sampled allowing essentially intact neurons to be imaged. These neurons Image analysis in 3‐D is as important as visualization in 3‐D. Automated methods of cell counting and analysis by nuclear detection as well as tracing of individual neurons are presented. © 1994 Wiley‐Liss, Inc.
Quantitative three‐dimensional confocal microscopy of synaptic structures in living brain tissue
Authors: Hosokawa Toshiyuki , Bliss Timothy V. P. , Fine Alan
Published: February 2005

In order to study changes in synaptic structure that accompany learning and memory, we have developed optical methods to visualize dendritic spines and presynaptic terminals in living, electrically monitored brain slices maintained in vitro. Focal microapplication of the fluorescent lipophilic dye DiI provides Golgi‐like staining of small numbers of cells and processes that can be resolved clearly using confocal microscoopy; viability of stained cells is established by exclusion of the fluorescent DNA‐binding dye ethidium bromide. Serial optical sections are enhanced by deconvolution and other image processing methods. The resulting high‐resolution images are combined in an automated procedure to generate three‐dimensional reconstructions, in which submicron synaptic structures can be viewed and measured. These unbiased methods allow volume changes in individual, living synaptic structures to be assessed quantitatively over periods of hours or days in development or in response to stimulation, drug application, or other perturbations. © 1994 Wiley‐Liss, Inc.
Hyaluronate distribution in the regenerating retinal pigment epithelium of the rabbit: A study using confocal laser scanning microscopy
Authors: Korte Gary E. , Moskowitz Leslie , Mrowiec Ewa , Hamou Daniel
Published: February 2005

The distribution of hyaluronate (HA) in regenerating retinal pigment epithelium (RPE) of the rabbit was examined using immunohistochemistry and confocal laser scanning microscopy. The goal was to determine if there is a correlation between differentiation and HA expression, like that seen in developing tissues, where HA accumulates and then disappears as the tissue matures. In normal RPE cells HA is associated mainly with the apical surface. In regenerating RPE (produced by i.v. injection of sodium iodate to damage the epithelium, regeneration arising from spared cells), HA exhibits a patchy distribution among the more immature cells and is especially prominent where they overlap or pile up on each other. Where cells are more mature and form a compact monolayer of cells, HA is expressed mainly on the apical surface, as in normal RPE. The accumulation of HA among the more immature cells in the regenerating epithelial sheet supports the hypothesis that HA influences differentiation by suppressing cell‐cell associations until the proper time for their formation. © 1994 Wiley‐Liss, Inc.
Three‐dimensional organization of neuronal and glial processes: High voltage electron microscopy
Authors: Hama Kiyoshi , Arii Tatsuo , Kosaka Toshio
Published: February 2005

Neurons and glia cells in the mammalian central nervous system have many complicated processes. They are too fine for light microscopic study and too complicated and widely spread for thin section electron microscopy. High‐voltage electron microscopic (HVEM) stereo observation of thick Golgi preparation provides detailed 3‐D images of their processes. Three‐dimensional fine structures of astocytic processes in the neuropile and on the surface of neuronal somata, and those of the ruffed cell axon initial segment and thorny excrescences of CA3 pyramidal cell dendrites, are elucidated with the aid of HVEM stereoscopy of thick Golgi preparations. In addition, some results obtained by 3‐D morphometrical analysis of dendritic spines using HVEM stereo images are shown.

The examples presented here clearly show the usefulness of high‐voltage electron microscope stereo observation of thick specimens for detailed morphological and morphometric study of the central nervous system. © 1994 Wiley‐Liss, Inc.
Application of serial sectioning and three‐dimensional reconstruction to the study of taste bud ultrastructure and organization
Authors: Royer Suzanne M. , Kinnamon John C.
Published: February 2005

The lingual taste buds of mammals are complex organs containing dozens of cells of varying morphology and numerous nerve fibers that are intermingled among the cellular processes. Some of the taste bud cells form synaptic contacts with these nerve fibers. Important questions remain to be answered regarding the structure and function of the cells of various types within taste buds and the means by which responses to gustatory stimuli are transmitted to the nerve fibers that communicate with the brain. Using both conventional and high voltage electron microscopy, we have examined serially sectioned taste buds from the tongues of mice and rabbits in order to address these issues and to obtain more complete information than that available from sampling of sections. The technique of computer‐assisted 3‐D reconstruction was used to generate models of whole taste buds and individual cellular and neural elements within taste buds from the serial sections.

Analysis of serially sectioned taste buds from mice and rabbits has revealed that in both of these species relatively few (30% or less) of the cells within the taste buds form synaptic contacts with nerve fibers. In the foliate taste buds of rabbits, all of the cells that are presynaptic to nerve fibers are of a single morphological type (type III). The cells that are presynaptic to nerve fibers within the taste buds of mice are morphologically diverse. A pattern of synaptic connectivity exists within murine taste buds such that a given nerve fiber receives synaptic input only from taste cells that are ultrastructurally similar. In the taste buds of both mice and rabbits, we have observed both divergence and convergence of synaptic input from the putative taste receptor cells onto nerve fibers, suggesting that at the level of the taste bud there is some integration of the information generated by individual receptor cells. In addition to typical chemical synapses, other cytoplasmic specializations (such as subsurface cisternae and atypical mitochondria) may be involved in interactions between taste bud cells and nerve fibers. © 1994 Wiley‐Liss, Inc.
Sulfated glycoprotein‐2 synthesized by nonciliated cells of the efferent ducts is targeted to the lysosomal compartment
Authors: Igdoura S. A. , Hermo L. , Morales C. R.
Published: February 2005

The epithelial nonciliated cells of the efferent ducts are specialized in internalizing many luminal substances. The nonciliated cells actively endocytose sulfated glycoprotein‐2 (SGP‐2), a major secretory protein of Sertoli cells and a homologue of human apolipoprotein J. This study was undertaken to investigate the internalization of Sertoli‐derived SGP‐2 and synthesis of an endogenous efferent duct form of SGP‐2 by nonciliated cells targeted to their secondary lysosomes on animals whose efferent ducts were ligated and/or received injections of tunicamycin. The regulation of synthesis of the endogenous form of SGP‐2 within nonciliated cells by hormones in general and testosterone in particular was also examined using hypophysectomized and castrated animals with or without subsequent testosterone replacement. Quantitative electron microscope immunocytochemistry was performed on groups of animals fixed with 4% paraformaldehyde and 0.5% glutaraldehyde in phosphate buffer for each experimental condition and their controls. In each case, the labeling density (number of gold particles/μm2) within the endosomal (endosomes) and lysosomal (dense multivesicular bodies and secondary lysosomes) compartments was calculated. The results revealed that ligation of the efferent ducts resulted in a significant decrease in the labeling density of the endosomal and lysosomal compartments. However, a baseline of about 18% of controls was still observed in the lysosomal compartment 24 h after ligation. In this compartment similar values were noted 24 h after tunicamycin treatment in conjaction with or without ligation. These results suggest that an endogenous form of SGP‐2 is synthesized by nonciliated cells and presumably targeted via small vesicles from the Golgi apparatus to the lysosomal compartment, but that the major portion of SGP‐2 within this compartment is derived via endocytosis of testicular SGP‐2. Hypophysectomy and castration also showed significant decreases in the labeling densities of these two compartments, but again a baseline level of labeling was noted in the lysosomal compartment. Subsequent testosterone administration to 7‐day hypophysectomized or castrated animals had no effect on the labeling density of the lysosomal compartment, as values comparable to the effect of hypophysectomy or castration alone were noted. Taken together these results suggest that the nonciliated cells of the efferent ducts synthesize an endogenous form of SGP‐2 that is targeted to the lysosomal compartment and which is not regulated by pituitary factors or testosterone. © 1994 Wiley‐Liss, Inc.
Crystal structure, chemical composition, and extended defects of the high‐Tc (Bi,Pb)2Sr2Can−1CunO4+2n+δ compounds
Authors: Eibl O.
Published: February 2005

This paper summarizes results obtained by high‐resolution transmission electron microscopy on the crystal structure and microstructure of the (Bi,Pb)2Sr2Can−1CunO4+2n+δ high‐Tc superconducting oxides. The experimental basis for the work presented here are high‐resolution structure images obtained at ultra‐thin (3 nm) areas of carefully prepared transmission electron microscope (TEM) samples. The analysis was carried out on a 400 kV TEM equipped with a pole piece yielding 0.17 nm point‐to‐point resolution. From the images obtained the projected crystal potential of the cations can be extracted directly, as confirmed by detailed image simulation. Structural analysis of the oxygen sublattice remains an unsolved problem by high‐resolution TEM (HRTEM), mainly because of the small scattering factors, and thus the contribution of the oxygen sublattice to the image contrast is small. The (Bi,Pb)2Sr2Can−1CunO4+2n+δ phases are modulated structures that can be understood as an average structure plus a superimposed displacement field. The crystal structure consists of BiO double layers and perovskite‐type cuboids (containing Sr, Ca, Cu, and O), which are sandwiched between the BiO double layers. The displacement field can be directly analyzed by HRTEM, and the largest displacement amplitudes of 70 pm were determined for the Bi atoms in the n = 1 compound. The chemical composition of the n = 2 and n = 3 compounds was determined by EDX in the TEM for the cation sublattice. A significant (Ca + Sr) deficiency (approximately 10%) with respect to Cu was found. The (Sr + Ca)/Cu mole fraction ratio was 1.31 for the Bi‐2212 phase and 1.14 for the Bi(Pb)‐2223 phase. The oxygen content cannot be determined by EDX in the TEM with the accuracy necessary for a correlation with electrical and superconducting properties. The defect structure present in these materials, that is, intergrown lamellae with different crystal structures and equal or different chemical compositions, stacking faults, and grain boundaries, is summarized. The importance of grain boundaries for understanding and improving superconducting properties is emphasized. © 1995 Wiley‐Liss, Inc.
Effects of hormones on the prostate in adult and aging men and animals
Authors: Sinowatz F. , Amselgruber W. , Plendl J. , Kölle S. , Neumüller Ch. , Boos G.
Published: February 2005

Literature on the effect of steroid hormones (androgens, estrogens, and other steroids), of peptide hormones (e.g., prolactin), and growth factors (e.g., EGF, FGF, TGF‐β), on the effect of castration and of experimental hormone application on the prostate is reviewed. Androgens have inductive, repressive, and interactive effects. They counterbalance an agonistic effect on proliferation and an antagonistic effect on cell death; they may influence DNA synthesis and induce the synthesis of substances with mitogenic effects on the prostate. Estrogens exert direct and indirect effects on the prostate. They suppress the secretion of gonatropins, thus repressing testicular androgen secretion. They stimulate the fibromuscular stroma and induce squamous metaplasia of the epithelium. Estrogens may also be involved in the onset of benign prostatic hyperplasia. Prolactin is preferentially bound in the diseased human prostate. An abundance of information has been gained on EGF, FGF, TGF‐β, and other growth factors. They may be involved in the development of prostatic hyperplasia. Castration leads to a striking reduction in prostatic size in a short period of time due to autophagic and heterophagic processes. In castrated individuals, the prostate is enriched in androgen‐independent cells. Experimental hormone application involves the substitution of androgens as well as anti‐androgens, long‐term application of different hormones, and application of combinations of drugs. The results of several studies are described. Further directions in the field of prostate research should concentrate on the role of growth factors in prostate development and pathology and on the effect of certain lectins on prostate diseases. We think that the investigation of interactions between steroid hormones and growth factors in normal and pathological neovascularization of the prostate is important. © 1995 Wiley‐Liss, Inc.
Morphological analysis of gastro‐esophageal diseases by molecular cell techniques
Authors: Jankowski Janusz , Henders Karen , Viaene Anne , Baert Johann , Long Lu Qi
Published: February 2005

The molecular cell sciences have had a great impact in the analysis of the genetic and epigenetic events of esophageal and gastric tumorigenesis. In other regions of the alimentary tract such as the colon, the serial identification of the molecular events in the corresponding morphological lesions is perhaps most advanced. This is, in part, due to the relative ease of the histological characterisation of the premalignant lesions. In this regard the analysis of morphological and molecular adaptation in the alimentary tract is inextricable. This review aims, therefore, to judiciously assess the relative applications of contemporary techniques in investigative histopathology. © 1995 Wiley‐Liss, Inc.
Scanning electron microscopy of the human esophagus: Application to barrett's esophagus, a precancerous lesion
Authors: Shields H. M. , Sawhney R. A. , Zwas F. , Boch J. A. , Kim S. , Goran D. , Antonioli D. A.
Published: February 2005

In Barrett's esophagus, metaplastic columnar epithelium replaces the normal squamous epithelium. The importance of this lesion lies in the increased incidence of adenocarcinoma of the esophagus occuring in patients with Barrett's esophagus. We characterized the surface epithelial cells of Barrett's esophagus using quantitative scanning electron microscopy. Three distinct surface cell types, in addition to the goblet cell, were recognized in Barrett's epithelium: the gastric‐like cell and the intestinal‐like cell, both of which were similar to normal gastric and small intestinal surface cells, respectively, by quantitative scanning electron microscopy, and the variant cell which had a range of surface features. In four biopsy specimens from the squamo‐Barrett's junction in three patients, we found the distinctive cell that had features intermediate between those of squamous and columnar epithelium. On the distinctive cell's surface there are two disparate structures not normally present on the same cell in the gastrointestinal tract: microvilli (a scanning electron microscopy feature of glandular epithelium) and intercellular ridges (a scanning electron microscopy feature of squamous epithelium). The surface characteristics of this cell were almost identical to those of cells found in the transformation zone of the uterine cervix, an area in which squamous epithelium physiologically replaces columnar epithelium. Scanning electron microscopy of Barrett's esophagus has increased our understanding of this precancerous lesion by showing striking cellular heterogeneity. It has also identified the distinctive cell which may represent an intermediate step in the development of Barrett's epithelium during which the surface characteristics of two different cell types, columnar and squamous, coexist in the same cell. © 1995 Wiley‐Liss, Inc.
Quantitation of fibroblast population growth rate in situ using computerized image analysis
Authors: Perricone Michael A. , Saldate Veronica , Hyde Dallas M.
Published: February 2005

The development of computer‐assisted image analysis has provided the technology to rapidly determine the population size of cultured cell monolayers in situ. We have adapted this technology to determine the population growth rate of cultured fibroblasts for use in a highreplicate format. Human lung fibroblasts were seeded into 1/2 A 96‐well plates that had one‐half the culture area of standard 96‐well plates. The cells were cultured in medium supplemented with different concentrations of FBS and on days 0, 1, 2, 3, 5, and 7, and their nuclei were stained with propidium iodide. A microscopic field representing one‐quarter of a well of fluorescent nuclear images was captured onto a Macintosh computer, and the number of nuclei were counted using an image analysis software program. There were no significant differences between the number of nuclei counted manually and the number counted using computer‐assisted software, until day 7 where the cells were multilayered (P < 0.05). This image analysis method was compared to other assays typically used to estimate cell proliferation or population size, namely hemocytometer counting, a rapid colorimetric staining assay using naphthol blue‐black, and [3H]‐thymidine incorporation. The growth rates derived using image analysis were in close agreement with results derived from hemocytometer counts and [3H]‐thymidine incorporation. However, the growth rates of cells grown in high concentrations of FBS as determined using naphthol blue‐black were substantially lower than results from image analysis. We conclude that this adaptation of computer‐assisted image analysis provides a method to derive accurate growth curves by directly counting the number of cells in a large number of replicates. © 1995 Wiley‐Liss, Inc.
On the use of local statistical properties in focusing microscopy images
Authors: Lipton Alan , Breen Edmond J.
Published: February 2005

Techniques to extract focus properties of microscopy images are many and varied. Many of them, however, rely on the summation of local statistical properties. Presented here is an examination of conventional focus determination algorithms, and a new method based on planar histograms of these local statistical properties. It is shown that this new method provides finer discernment of the focus properties of an image, and provides a means to extend the focus of an optical microscopy system. © 1995 Wiley‐Liss, Inc.
Myocardial gap junction organization in ischemia and infarction
Authors: Peters Nicholas S.
Published: February 2005

Ischemia causes an increase in myocardial resistivity and a decrease in conduction velocity, thereby enhancing cardiac contractile dysfunction and arrhythmic tendency. Myocardial gap junctions, as principal determinants of conduction velocity, may, therefore, be expected to be deranged in ischemia. Despite a lack of consensus, attempts at correlating gap junction ultrastructural morphology with functional state have revealed the component connexons of gap junctions in freeze‐fractured myocardium to be in multiple small hexagonal arrays, tending to become randomly distributed and compacted under uncoupling conditions. Further hypoxic uncoupling causes ultrastructural damage and a reduction in gap‐junctional surface area. Immunohistochemical detection of connexin43 gap junctions in chronically ischemic non‐infarcted human myocardium demonstrates a reduction in junctional surface area within a normal number of intercalated disks per myocyte, and with a normal distribution of junction sizes. In healed canine infarction there are smaller and fewer gap junctions in the fibrotic myocardium adjacent to infarcts, with reductions in overall gap‐junctional content and the proportion of side‐to‐side vs. end‐to‐end intercellular connections. Immunohistochemical examination of intact human ventricular myocardium shows the myocytes immediately abutting healed infarcts to hve connexin43 gap junctions spread longitudinally over the cell surfaces, and not in discrete transversely orienated intercalated disks as in normal myocardium. Early after canine infarction, and before fibrotic healing, the connexin43 gap junctions in myocytes abutting the infarct show disorganization similar to that described in healed human infarcts, suggesting that this disturbance is an early pathophysiological cellular response, and not simply due to later fibrotic distortion. Such changes in gap‐junctional organization in myocardial ischemia and infarction may be implicated in the elusive link between subcellular structure, contractile dysfunction and arrhythmogenesis. © 1995 Wiley‐Liss, Inc.
Ultrastructure and histochemistry of acid mucus glycoproteins in the estrous mammal oviduct
Authors: Jansen Robert P. S.
Published: February 2005

The mucous surfaces of the oviducts of mammals, especially humans, are dependant on estradiol. The mucus glycoproteins and glycocalyceal glycoproteins have, however, barely been studied. Biochemical analyses have focussed on the relatively low molecular weight glycoproteins likely to be found in more serous‐type granules of the ampulla and not on the very high MW glycoproteins typical of mucus and represented in the isthmus by morphological evidence of mucus secretion. Quantitatively, secretion from the ampulla is likely to predominate, because of its huge surface area compared with the isthmus. But functional closure of the isthmus under the influence of estradiol in the absence of progesterone means that it is the isthmus where luminal secretions accumulate—and where mucus glycoproteins will exert their most important effects on spermatozoa ascending the reproductive tract, and then on fertilized ova en route to the uterus. Further study of the extracellular, intraluminal, carbohydrate‐rich environment of the oviductal isthmus, especially in humans, is likely to prove rewarding. Sampling of these secretions is now feasible using transvaginal, transuterine fallopian tube catheters that are in clinical use. © 1995 Wiley‐Liss, Inc.
Myelin mutants: New models and new observations
Authors: Lunn Katharine F. , Fanarraga Monica L. , Duncan Ian D.
Published: February 2005

The myelin mutants have been extensively used as tools to study the complex process of myelination in the central and peripheral nervous system. A multidisciplinary approach to the study of these models ultimately allows a correlation to be made between phenotype and genotype. This correlation may then lead to the formation of new hypotheses about the functions of the products of genes involved in myelination. This review presents a number of new myelin mutants which have recently been described. The species involved include mouse, rat, rabbit, hamster, and dog models. The genetic defect has not been elucidated in all of these animals, but most have been characterized clinically and pathologically, and, in some cases, biochemically. In addition, a better known myelin mutant, the trembler mouse, is discussed. Recent molecular findings have brought this fascinating mutant to the forefront of the field of peripheral nervous system research. The range of abnormalities in the mutants described in this review includes defects in specific myelin proteins, suspected abnormalities in membrane formation, and apparent defects of the oligodendrocyte cytoskeleton. These findings underscore the complexity of the myelination process and highlight the numerous ways in which it can be disrupted. © 1995 Wiley‐Liss, Inc.
Two models of multiple sclerosis: Experimental allergic encephalomyelitis (EAE) and theiler's murine encephalomyelitis virus (TMEV) infection. A pathological and immunological comparison
Authors: Dal Canto Mauro C. , Melvold Roger W. , Kim Byung S. , Miller Stephen D.
Published: February 2005

Theiler's murine encephalomyelitis virus (TMEV) infection and experimental allergic encephalomyelitis (EAE) are considered among the best models of human multiple sclerosis (MS). In both models, clinical disease is characterized by paralysis, while pathological changes consist of inflammatory demyelination. In both models there is a genetic influence on susceptibility/resistance to the development of disease. This has been thoroughly studied in TMEV infection, and it has been found to depend on both major histocompatibility complex (MHC) and non‐MHC genes. At least four genes have been so far identified. Because of this genetic influence, some strains of mice are more susceptible to both clinical and pathological changes than others, and susceptibility appears to best correlate with the ability of a certain murine strain to develop a delayed‐type hypersensitivity (DTH) response to viral antigens. We have also observed that even among mice which are equally susceptible clinically, striking differences may be seen under pathological examination. These consist of different gradients of severity of inflammation, particularly in regards to the macrophage component. There is an inverse relationship between the number of macrophages, and their length of stay in the CNS, and the ability of mice to remyelinate their lesions. The most severe lesions are in SJL/J mice, and remyelination in this strain is extremely poor. The least severe lesions in terms of macrophage invasion are in strains such as NZW and RIIIS/J, and these are able to remyelinate lesions very successfully. Murine chronic relapsing EAE (CR‐EAE) shows pathological changes in many ways similar to those in TMEV‐infected SJL/J mice, although less severe in terms of degrees of macrophage infiltration and tissue destruction. Mice with CR‐EAE have a correspondingly limited ability to remyelinate their lesions. In both models the pathology appears to be mediated through a DTH response. However, while in EAE the DTH response is clearly against neuroantigens, the response in TMEV infection is against the virus itself. The end result in both models would be that of myelin destruction through a lymphotoxincytokine‐mediated mechanism. The importance of the DTH response in both models is well illustrated by the effects of tolerance induction in EAE and TMEV infection to neuroantigens and virus, respectively. These are important models of human MS, since the current hypothesis is that a viral infection early in life, on the appropriate genetic background, may trigger a secondary misdirected immune response which could be directed either against myelin antigens and/or possible persistent virus(es). © 1995 Wiley‐Liss, Inc.
Effects of extracellular matrix on differentiation of mouse fetal gonads in the absence of mesonephros in vitro
Authors: Kanai Yoshiakira , Kanai‐Azuma Masami , Kurohmaru Masamichi , Yazaki Kazumori , Hayashi Yoshihiro
Published: February 2005

The influence of mesonephric tissues and the extracellular matrix on mouse gonadal differentiation was examined in vitro. Gonadal ridges, with or without the adjacent mesonephric region, were removed from mouse embryos on day 12 post coitum (p.c.), and cultured in the presence or absence of reconstituted basement membrane (matrigel) for 5 days. Culturing control undifferentiated testes with mesonephric tissues induced normal testicular differentiation. When testes without mesonephric tissues were cultured in the absence of matrigel, testicular cord formation was not observed in the explants. Sertoli cells were irregularly arranged in the testicular parenchyma, and no continuous basal lamina was formed around the Sertoli cells. However, when testes without mesonephric tissues were embedded in matrigel and cultured for 5 days, the Sertoli cells were organized into testicular cord‐like structures. The Sertoli cells positioned at the base of the cord‐like structures were closely connected to the matrigel at their basal surface, and showed a polarized distribution of vimentin filaments in their basal cytoplasm. Leydig cells, on the other hand, were differentiated in all testicular explants. In all ovarian explants, germ cells normally entered meiotic prophase. Therefore, these findings indicate that the extracellular matrix permits testicular differentiation in the absence of the mesonephros, and that removal of mesonephric tissues leads to developmental failure of cord formation because the components of the extracellular matrix around pre‐Sertoli cells are incomplete. © 1995 Wiley‐Liss, Inc.