bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitric oxide synthase‐containing neurons in the pig large intestine: Topography, morphology, and viscerofugal projections
Authors: Barbiers Martine , Timmermans Jean‐Pierre , Scheuermann Dietrich W. , Adriaensen Dirk , Mayer Bernd , De Groodt‐Lasseel Marie H. A.
Published: February 2005

The distribution of neurons that are capable of synthesizing nitric oxide (NO) has been demonstrated in the porcine large intestine by means of NO synthase (NOS) immunocytochemistry and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry. An overall colocalization of NOS immunoreactivity and NADPHd staining was observed. Nitrergic neurons were abundant in the myenteric and outer submucous plexus of the caecum, colon, and rectum. Only a few nitrergic perikarya were seen in the inner submucous plexus of the colon and caecum, whereas a substantially larger number was observed in the rectum. Nitrergic nerve fibers were present in the three ganglionic nerve plexuses. Contrary to the outer longitudinal muscle layer and the mucosal region, the circular muscle layer received a dense nitrergic innervation. The nitrergic nerve cells were variable in size and shape, and several displayed vasoactive intestinal polypeptide (VIP) immunoreactivity (IR). Retrograde tracing studies revealed the existence of nitrergic neurons that project to the caudal (inferior) mesenteric ganglion. They were observed in the myenteric and outer submucous plexus of the transverse and descending colon and the rectum. These observations strongly suggest that several subpopulations of NO‐synthesizing neurons, namely, motor neurons and interneurons, should be distinguished in the porcine large intestine, thereby emphasizing the importance of NO as a biologically active mediator. © 1994 Wiley‐Liss, Inc.
Neuroepithelial endocrine and nervous system in the respiratory tract of Cynops pyrrhogaster with special reference to the distribution of nitric oxide synthase and serotonin
Authors: Adriaensen Dirk , Scheuermann Dietrich W. , Timmermans Jean‐Pierre , Gomi Toshiaki , Mayer Bernd , De Groodt‐Lasseel Marie H. A.
Published: February 2005

The respiratory tract of urodeles harbours an intramural nerve network comprising an innervated system of neuroepithelial endocrine (NEE) cells. However, striking differences have been noted between phylogenetically closely related species. Zamboni‐ or formaldehyde‐fixed whole‐mount preparations and sections of the saclike lungs of a Japanese salamander, Cynops pyrrhogaster, have been investigated for the immunocytochemical detection of nitric oxide synthase (NOS), serotonin (5‐HT), VIP, somatostatin, calcitonin, and bombesin; for the enzyme‐cytochemical demonstration of NADPH diaphorase (NADPHd); and for formaldehyde‐induced fluorescence. In addition, the ultrastructural morphology has been examined by using glutaraldehyde/osmium tetroxide fixed lung tissues. Ovoid 5‐HT‐immunoreactive (IR) NEE cells occur singly or grouped in the ciliomucous epithelium of the trachea and lungs of Cynops, and a few somatostatin‐, calcitonin‐, and bombesin‐like IR NEE cells are also observed. These cells exhibit a characteristic neuroendocrine morphology as seen with the electron microscope. In addition, large numbers of 5‐HT‐IR interstitial cells, with round to oval cell bodies and two or three long, slender, sometimes branching processes, are located preferentially along large blood vessels in the connective tissue capsule of the lung and trachea. Immunoelectronmicroscopy shows that 5‐HT is localized over large dense granules in the cell bodies and processes of these interstitial cells. NOS‐like immunoreactivity occurs in a nerve plexus composed of thick nerve bundles and nerve cells, and in a fine varicose nerve network that originates at least partly from intrapulmonary NOS‐containing nerve cells. VIP‐like immunoreactivity appears to be colocalized with NOS in the latter network. All NOS‐positive nerve fibres in the lungs of Cynops pyrrhogaster and Ambystoma mexicanum stain for NADPHd. It is concluded that the pulmonary NEE cells observed in Cynops pyrrhogaster are similar to those described in other vertebrate species and that the 5‐HT‐IR interstitial cells resemble mast cells. In addition, nitric oxide is likely to be a bioactive substance involved in nonadrenergic, noncholinergic inhibitory neurotransmission in the pulmonary nervous system of urodeles, where it may be colocalized with VIP. © 1994 Wiley‐Liss, Inc.
Adrenal medulla and Parkinson's disease
Authors: Stoddard Susan L. , Merkel Glenn J. , Cook Jennifer A. , Zinsmeister Alan R. , Carmichael Stephen W.
Published: February 2005

Parkinson's disease has been described as a multisystem disorder that includes alterations in the function of the autonomic nervous system. The activity of the adrenal medulla in this disease has not been thoroughly investigated. Previous reports are reviewed that demonstrate that the adrenal medullae of parkinsonian patients are compromised, having a decreased content of all catecholamines and several neuropeptides. An animal model was used to investigate whether the observations made in human patients were related to extended treatment with antiparkinsonian medications or were a natural concomitant of the disease. Administration of L‐dopa and/or carbidopa to C57BL mice for 4–16 weeks had no significant effect on the level of any of the adrenal medullary catecholamines. Treatment with MPTP 4–16 weeks prior to sacrifice did not deplete adrenal medullary catecholamines in these animals, thus not fully mimicking Parkinson's disease in this animal model. The only significant effect was an interaction between group (MPTP or control) and treatment with antiparkinsonian medications; L‐dopa, in the absence and presence of carbidopa, had opposite effects in the two groups. Based primarily on the lack of effect of antiparkinsonian medications on adrenal medullary catecholamines, it was concluded that the adrenal medullary depletion observed in human patients was a peripheral concomitant of Parkinson's disease. © 1994 Wiley‐Liss, Inc.
Morphological observations of small granule‐containing (Chromaffin) cells in the celiac ganglion of the guinea pig, with emphasis on cell contacts
Authors: Mascorro Joe A. , Breaux Todd F. , Yates Robert D.
Published: February 2005

Utilizing electron microscopic observation, several contacts between small, granule‐containing cells (SGC) and postganglionic neurons (PGN) in the celiac ganglion of the guinea pig have been observed. A SGC in very close association with a PGN was seen to receive a distinct synaptic contact that contained many vesicles with dense cores. This contact was morphologically unlike cholinergic synapses previously reported on chromaffin cells. Because the SGC and PGN were clearly separated by a thin rim of satellite cell cytoplasm mutual to both cells, it is not known how or if the SGC would possibly exert a synaptic or paracrine effect on the PGN. Also, intraganglion SGC existed as large well‐vascularized islands within the celiac ganglion. These intraganlion clusters sometimes contained more than 50 cells and perhaps could be considered to function as localized neuroendocrine components within the ganglion by secreting granule products into the nearby blood vessels for local or distant effects, although this certainly is not known. This work reports a unique synaptic ending upon a single‐occurring SGC, which, in turn, closely approximates a ganglion neuron in a soma‐somatic relationship. In addition, a very close association (but no actual contact) was observed between granule‐containing processes, presumably emanating from the intraganglion clusters, and PGN. Whatever the function of ganglionic SGC may be, the exact relationship between SGC and PGN presumably would be of great interest and potential importance. © 1994 Wiley‐Liss, Inc.
Subcellular localization and quantitative analysis of Toxoplasma gondii target antigens of specific immunoglobulins G, M, A, and E
Authors: Kumolosasi E. , Bonhomme A. , Lepan H. , Marx C. , Foudrinier F. , Pinon J. M. , Beorchia A. , Pluot M.
Published: February 2005

The target antigens of specific immunoglobulins G, M, A, and E from patients with acquired acute toxoplasmosis were determined using immunocytochemistry. The relative repartition of these antigens in four cellular compartments of Toxoplasma (membrane complex, apical area, rhoptries, and dense granules) was quantitatively evaluated. Rhoptry antigens mainly react positively with IgA. Membrane, submenbrane area (membrane complex), and rhoptry antigens are immunodominant for IgA and IgM. Apical area antigens are recognized by IgM two times more than IgG and IgA. IgE recognized only rhoptry antigens.

The localization of pathogenetically antigenic components and their identification by the immune system appeared to be of importance for selection of immunodominant or recombinant antigens. Such localization would improve laboratory diagnosis of serious congenital toxoplasmosis or in immunocompromised patients with toxoplasmic complications after cyst reactivation. © 1994 Wiley‐Liss, Inc.
Localizing sites of intradendritic electrophysiological recordings by confocal light microscopy
Authors: Smith Karen L. , Turner James N. , Szarowski Donald H. , Swann John W.
Published: February 2005

Studies were undertaken to develop microscopic methods and imaging procedures that would permit identification of sites of intradendritic microelectrode recordings from pyramidal cells in hippocampal slice preparations. Intradendritic recording were obtained with sharp microelectrodes filled with the dye lucifer yellow. Following a recording session a neuron was iontophoretically injected with the dye and imaged by fluorescence videomicroscopy. Images were stored on videotape for later analysis. They provided a record of the location of the microelectrode recording site. After withdrawal of the microelectrode, slices were processed histologically and imaged a second time with a Bio‐Rad 600 confocal attachment on an Olympus BH‐2 microscope. Confocal images provided detailed anatomical information in three dimensions. In most instances, a clear identification of the recording site was achieved by comparing video images containing the recording electrode and confocal images.

Neurophysiological recordings obtained from proximal and distal apical dendrites were markedly different. Proximal dendritic recordings were similar to those obtained from pyramidal cell soma. However, distal dendrites were not electroresponsive when depolarized by intracellular current injection. The techniques described here, or variations that employ patch electrodes, could provide valuable information that should further an understanding of the properties of dendrites in the central nervous system. © 1994 Wiley‐Liss, Inc.
Two Golgi integral membrane proteins (GIMPS) exhibit region‐ and cell type‐specific distribution in the epididymis of the adult rat
Authors: Suarez‐Quian Carlos A. , Jelesoff Nicole
Published: February 2005

The epididymis participates in the post‐testicular maturation and storage of spermatozoa by secreting proteins into the tubule lumen in a region‐specific fashion. The underlying molecular mechanisms leading to biogenesis of these region‐specific differences, however, are not known, although components of the Golgi complex membrane container must undoubtedly be intimately involved. Two monoclonal antibodies raised against Golgi integral membrane proteins, recognizing either the cis (GIMPc) or trans Golgi (GIMPt) cisternae, were used as molecular probes of these regions to begin the characterization of the Golgi complex of in vivo and in vitro epididymal cells. Immunolocalization of GIMPs was performed on frozen sections and in cultured cells using biotin‐streptavidin‐peroxidase immunocytochmistry. In tissue sections, immunostaining of GIMPt was extremely robust in the supranuclear cytoplasm throughout the epididymis. In contrast, no GIMPc immunostaining was detected in the initial segment or in clear cells of the distal caput, corpus, and cauda. Immunodetection of GIMPc and GIMPt in epididymal cells in vitro revealed a reticular, perinuclear pattern, and NH4Cl treatment preferentially disrupted the GIMPt immunolocalization. These results characterizing the molecular components of the Golgi complex will form the basis of additional studies to gain further insight into mechanisms leading to generation of regional differences in epididymal function. © 1994 Wiley‐Liss, Inc.
Freeze‐fracture study of cell junctions in the epididymis and vas deferens of a seasonal breeder: The mink (Mustela vison)
Authors: Pelletier R.‐Marc
Published: February 2005

The present study used the freeze‐fracture technique and vascular infusion of horseradish peroxidase (HRP) as a junction permeability tracer, visible in thin sections, to investigate potential seasonal variations in the mink epididymis and vas deferens cell junctions. The junctions were studied in kits during the neonatal period, during and after puberty, and during adulthood monthly throughout the annual reproductive cycle. Results showed the existence, at the time of birth, of a junctional complex joining ductal cells that reached the lumen of the epididymis and vas deferens. The lumenal impermeable segment of the junctional complex was characterized by the presence of an occluding zonule made up of continuous tight junctional ridges extending around the perimeter of the cell. The basal permeable segment of the junctional complex contained mainly discontinuous ridges with frequent forming gap and tight junctions next to adhering junctions. Receding annular junctions were present in the apical and lateral cytoplasm of principal and clear cells. The membrane domain apical to the occluding zonule bore 30–35 nm exo/endocytosis blebs and 40–60 crenations associated with deforming tight and gap junctions made up of randomly scattered particles. Patterns of junctional strands varied greatly from one principal and/or clear cell to another. However, cell junctions did not significantly vary from the neonatal period to adulthood nor from breeding to testicular regression. Anatomical subdivisions of the epididymis with fewer junctional strands per zonule and high diversity in their patterns exhibit no permeability differences to HRP when compared with subdivisions containing more numerous strands. The junctions were impermeable during the neonatal period and throughout the annual reproductive cycle. The following conclusions were reached: (1) a competent occluding zonule developed in the mink epididymis and vas deferens before it did in the testis; (2) the number of strands and the diversity of patterns did not correlate with permeability differences; (3) after the development of a lumen in the testicular excurrent duct, neither receding cellular changes caused by testicular regression nor seasonal passage of a bolus of sperm through the duct modified the occluding zonules; and (4) in the testicular excurrent duct, junction modulation (i.e., formation and deformation) paralleled that in the testis and followed the direction of the synthesis‐transport‐secretion process. © 1995 Wiley‐Liss, Inc.
Epididymal epithelium: Its contribution to the formation of a luminal fluid microenvironment
Authors: Hinton Barry T. , Palladino Michael A.
Published: February 2005

To understand the process of sperm maturation, an understanding of interactions between the spermatozoa with the luminal fluid microenvironment and with the epididymal epithelium is necessary. The composition of epididymal luminal fluid of several species is well documented but the manner by which the epididymis contributes to the formation of this specialized milieu is not so well understood. A major role played by the epididymis is to finely regulate the movement of molecules into and out of the lumen. This ensures that as spermatozoa progress along the duct they are exposed to a continually changing, but optimal environment necessary for their maturation and survival. This review focusses on our current understanding of the contributions of the epididymal epithelium to the formation of a specialized luminal fluid microenvironment. The role of the blood‐epididymis barrier, the composition of the epididymal luminal fluid, the permeability properties of the epididymal epithelium, and recent studies on a number of luminal fluid proteins and expression of the genes which encode these proteins are discussed. © 1995 Wiley‐Liss, Inc.
Androgen, estrogen, and progesterone receptors in normal and aging prostates
Authors: Srinivasan Ganesan , Campbell Edward , Bashirelahi Nasir
Published: February 2005

Testicular hormones regulate the growth and development of the prostate. The presence of androgen receptors in prostatic tissue and their importance in the normal development of the prostate has been established. Age‐related changes in the hormonal milieu, and perhaps steroid hormone receptor profile, could set in motion pathological changes leading to the onset of benign prostatic hyperplasia (BPH) or prostate cancer which primarily affect older men. The accumulation of dihydrotestosterone with age, the reawakening of the inductive potential of the prostatic stroma, the altered rate of apoptosis with age, and the age‐related changes in the ratio of testosterone: estrogen have all been implicated in the etiology of BPH. In addition to androgen receptors, several studies have documented the presence of estrogen and progesterone receptors in BPH and prostate cancer. So far, most studies have focussed on the correlation between the presence/absence of steroid hormone receptors and response to hormonal therapy. The molecular mechanisms by which these steroid hormone receptors regulate the onset or progression of BPH and prostate cancer are not yet clear. The chronological changes in the levels and distribution of steroid hormone receptors in normal prostatic tissue and the effect of such changes on the synthesis of growth factors, growth factor receptors, and oncogenes should be investigated. © 1995 Wiley‐Liss, Inc.
Comparison of SEM processing methods for cultured human lens epithelial cells grown on flat and microcarrier bead substrates
Authors: Cantu‐Crouch David , Howe William E. , McCartney Mitchell D.
Published: February 2005

The increasing importance of in vitro models has presented new challenges in SEM processing techniques. The present study has evaluated the quality of preservation of cultured human lens epithelial cells processed by critical point, Peldri II, and tert‐butyl alcohol drying. Specimens processed by critical point drying produced specimens with severe cracking of cell processes and microcracks across cell membrane surfaces. Peldri II and tert‐butyl alcohol drying eliminated breakage of the filopodia and lamellipodia as well as eliminating the microcracks across the apical membrane surface. The morphology of lens epithelial cells grown on Cytodex 3 beads appeared rounded with convoluted membrane surfaces. These morphological features were present for cells processed by all three methods. Cytodex 3 beads were subsequently shown to shrink 52% in diameter during dehydration, which results in an 89% reduction in volume for the bead. Cells grown on Biosilon beads, which do not shrink, had a morphology similar to the cells grown on a flat substrate. These results indicate that Peldri II and tert‐butyl alcohol drying offer an attractive alternative to critical point drying when preparing cultured cells for SEM. Interpretation of cultured cell morphology must consider shrinkage of the substrate material as a possible contributor to artifact. © 1995 Wiley‐Liss, Inc.
Developmental studies of dystrophin and other cytoskeletal proteins in cultured muscle cells
Authors: Kobayashi Takayoshi , Ohno Shinichi , Park‐Matsumoto Yong Choo , Kameda Noriyoshi , Baba Takeshi
Published: February 2005

We studied the developmental changes of localization of dystrophin and other cytoskeletal proteins, especially actin, spectrin and dystrophin related protein (DRP) using immunocytochemistry and quick‐freezing and deep‐etching (QF‐DE) method.

In development studies of mouse and human muscle cultures, some myoblasts had positive reactions to spectrin, DRP, and F‐actin, but not dystrophin. In aneurally cultured myotubes, dystrophin, DRP, and spectrin were localized diffusely in the cytoplasm and later in discontinous patterns on the plasma membrane, when myotubes became mature. Spectrin and DRP had more positive reactions in immature myotubes, compared with those of dystrophin.

In some areas of myotubes, dystrophin/spectrin and spectrin/actin were localized reciprocally. In innervated cultured human muscle cells, dystrophin and DRP were localized in neuro‐muscular junctions, which were co‐localized with clusters of acetylcholine receptors.

By using the QF‐DE method, dystrophin was localized just underneath the plasma membrane, and closely linked to actin‐like filaments (8–10 nm in diameter), most of which were decorated with myosin subfragment 1. In actin‐poor regions, spectrin was detected as well‐organized filamentous structures in highly interconnected networks with various diameters. DRP was distributed irregularly with granular appearance inside the cytoplasm and also under the plasma membrane in immature mouse myotubes.

Our present studies show that dystrophin, spectrin, and DRP are localized differently at the developmental stages of myotubes. These results suggest that dystrophin, spectrin, and DRP are organized independently in developing myotubes and these cytoskeletal proteins might play different functions in the preservation of plasma membrane stability in developing myotubes. © 1995 Wiley‐Liss, Inc.
Myoblast transfer and gene therapy in muscular dystrophies
Authors: Pagel Charles Neil , Morgan Jennifer Elizabeth
Published: February 2005

Myoblast transfer therapy and gene therapy have both been proposed as potential treatments for inherited myopathies, such as Duchenne muscular dystrophy (DMD). The success of myoblast implantation in mouse models, where problems such as immune rejection are easily overcome, have led to similar experiments being attempted on Duchenne patients with limited, if any, success. Gene therapy, either by viral vectors or direct injection of the plasmid, has also had some success in animal models. Although both techniques, either separately or in combination, show some promise for the treatment of DMD, there are still many issues to be investigated in animal models, including the following: What is the best source of muscle precursor cells (mpc), and how may sufficient cells be obtained? What is the best vehicle for gene therapy? How far from the injection site can an implanted cell or gene have an effect? How can immune rejection of the injected cells or introduced protein be overcome? Does the introduced dystrophin lead to improved muscle function? Can cardiac muscle can be successfully treated by gene therapy? Can skeletal muscle which has undergone a great deal of damage be improved by either cell or gene therapy? © 1995 Wiley‐Liss, Inc.
Nucleic acid compartmentalization within the cell nucleus by in situ transferase‐immunogold techniques
Authors: Thiry M.
Published: February 2005

In the present review, we report on recent results obtained by in situ transferaseimmunogold techniques as to the ultrastructural distribution of DNA and RNA within the cell nucleus. Special emphasis is placed on the various nucleolar components and the various enigmatic structures of the extranucleolar region: interchromatin granules, coiled bodies, and simple nuclear bodies. These data are discussed in the light of our current understanding of the functional organization of the cell nucleus. © 1995 Wiley‐Liss, Inc.
Subcellular distribution of peptides associated with gastric mucosal healing and neoplasia
Authors: Sarraf Catherine E. , Alison Malcolm R. , Ansari Tareq W. , Wright Nicholas A.
Published: February 2005

The trefoil peptides pS2 and human spasmolytic peptide are putative growth factors, particularly associated with mucus‐producing cells of the gastrointestinal tract including those of the stomach. The receptor for transforming growth factor alpha (TGF α) takes its name from one of its alternative ligands, epidermal growth factor and is called the epidermal growth factor receptor. Although there is immunoreactive epidermal growth factor in the stomach, it is TGF α and the epidermal growth factor receptor that are abundant. Immunolabelling at electron microscope level allows for subcellular localisation of antigens; pS2 and human spasmolytic peptide co‐localise to cytomembranes, including the Golgi apparatus, and thecae of surface/pit mucous cells. TGF α is abundant on the membranes of tubulovesicles of parietal cells and is also present in chief cells: in mucous producing cells it can be detected but not in association with mucous. The distribution of the epidermal growth factor receptor mimics that of TGF α but with preferential clustering on the basolateral membranes of gastric cells. The trefoil peptides are associated with healing and probably act, together with mucus, to protect the gastric mucosa and maintain a viable environment. TGF α, transduced via the epidermal growth factor receptor, inhibits gastric acid secretion, thus aids the trefoils in the maintenance of a gastric microenvironment conducive to healing after damage. TGF α, however, is also a potent mitogen; while this property plays a vital part in repairing mucosal defects, if this peptide or indeed its receptor are overexpressed, the result can be neoplasia. © 1995 Wiley‐Liss, Inc.
Ultramicrotomy of semiconductors and related materials
Authors: Glanvill S. R.
Published: February 2005

Ultramicrotomy has found novel application in materials research using transmission electron microscopy, for both analytical and high resolution work. Specimens 20–50 nm in thickness with lateral dimensions of up to 100 microns may routinely be prepared, with the additional advantage of precise area location for cross‐sectional samples from real devices (e.g., VLSI structures). Much of this work is possible through the availability of diamond knives with various included angles and lengths at reasonable cost. This paper reports on various applications of ultramicrotomy, in particular, lattice imaging of surfaces and interface regions from epilayers of II–VI compound semiconductors and related materials. Ultramicrotomed cross‐sections have enabled modern electron beam imaging, diffraction and analytical techniques to be brought to bear near surfaces and across interfaces of multilayer structures, yielding high spatial resolution information on crystallography, defect structure and composition. © 1995 Wiley‐Liss, Inc.
Gap junctions in the vertebrate retina
Authors: Cook Jeremy E. , Becker David L.
Published: February 2005

The vertebrate retina is a highly laminated assemblage of specialized neuronal types, many of which are coupled by gap junctions. With one interesting exception, gap junctions are not directly responsible for the ‘vertical’ transmission of visual information from photoreceptors through bipolar and ganglion cells to the brain. Instead, they mediate ‘lateral’ connections, coupling neurons of a single type or subtype into an extended, regular array or mosaic in the plane of the retina. Such mosaics have been studied by several microscopic techniques, but new evidence for their coupled nature has recently been obtained by intracellular injection of biotinylated tracers, which can pass through gap junctional assemblies that do not pass Lucifer Yellow. This evidence adds momentum to an existing paradigm shift towards a population‐based view of the retina, which can now be envisaged both as an array of semi‐autonomous vertical processing modules, each extending right through the retina, and as a multi‐layered stack of interacting planar mosaics, bearing some resemblance to a set of interleaved neural networks. Junctional conductance across mosaics of horizontal cells is known to be controlled dynamically with a circadian rhythm, and other dynamically‐regulated conductance changes are also likely to make important contributions to signal processing. The retina is an excellent system in which to study such changes because many aspects of its structure and function are already well understood. In this review, we summarize the microscopic appearance, coupling properties and functions of gap junctions for each cell type of the neural retina, the regulatory properties that could be provided by selective expression of different connexin proteins, and the evidence for gap junctional coupling in retinal development. © 1995 Wiley‐Liss, Inc.
Spatial organization of cardiac gap junctions can affect access resistance
Authors: Hall James E. , Gourdie Robert G.
Published: February 2005

In the heart, gap junctions electrically couple myocytes together. Electron‐ and light‐microscope‐based analyses have revealed that cardiac gap junctions show a variety of organizational patterns. At the level of gap‐junctional channel aggregates, freeze fracture has demonstrated diverse channel packing arrangements in the membranes of different myocardial tissues. Ultrastructural and immunohistochemical studies have shown variation and specialization in the 3‐dimensional spatial distribution of gap junctional contacts between different types of myocardial cells. Here, we estimate the access resistance of various configurations of gap junctions using physical principles and explore how certain of these specializations in gap‐junctional organization may influence access resistance, a potentially important determinant of electrical conductance between coupled myocardial cells. © 1995 Wiley‐Liss, Inc.
Oviduct during early pregnancy: Hormonal regulation and interactions with the fertilized ovum
Authors: Murray Mary K. , Desouza Mary M. , Messinger Susan M.
Published: February 2005

The cyclic fluctuations in circulating levels of 17β‐estradiol and progesterone that occur during the menstrual or estrous cycle are responsible for dramatic, cyclic changes in the epithelial lining and secretory status of the mammalian oviduct. The timely transition in the synthesis and release of oviduct proteins, due to the ovarian steroids, and their interactions with oocytes, sperm, and the fertilized ovum underscore key biological events during gamete interactions and early embryonic cleavage. The regulation of these secretory alterations during the first few days of pregnancy is discussed with respect to the influence of the ovarian steroids, their interactions with the embryo microenvironment, and the possible ways in which they may mediate the critical reproductive events of fertilization and embryo development. © 1995 Wiley‐Liss, Inc.
Method for jet polishing two‐phase materials
Authors: Witcomb M. J. , Dahmen U.
Published: February 2005

A two‐stage jet polishing technique is described which, utilising the effects of the characteristic current‐voltage behaviour of electropolishing solutions, can produce excellent TEM foils of relatively coarse two‐phase materials. © 1995 Wiley‐Liss, Inc.
Mammalian parathyroids: Morphological and functional implications
Authors: Wild Peter , Setoguti Takao
Published: February 2005

Fixation with aldehydes is achieved either by immersion or perfusion. The parenchyma of parathyroid glands fixed by immersion consists of dark cells containing a lot of membranes of those organelles which are concerned with hormone secretion, light cells which are poor in these organelles, intermediate forms between the two, and multinuclear syncytial cells. They have been attributed to represent different functional stages of secretory activity, the dark cell being in an active form, the light cell in a resting form. Studies of the parathyroids of mice, rats, rabbits, cats, dogs, pigs, cattle, sheep, goats, and horses employing various fixation protocols clearly demonstrate that light cell variants and multinuclear syncytial cells are formed during improper immersion fixation as a result of membrane disintegration. Parathyroids fixed by perfusion or by immersion in an appropriate fixation medium comprise only one cell type which correspond to the dark chief cell. Parathyroid cells are polar cells bearing some of the rough endoplasmic reticulum in the basal pole, the rest of it, the Golgi complex, and secretory granules in the apical pole. The secretory product is released by exocytosis at the apicolateral domain of the plasma membrane into the intercellular space. Secretory activity can be altered experimentally, leading to drastic changes in the amount of cell membrane related to hormone synthesis, intracellular transport, exocytic release, and secretion coupled membrane retrieval. The sensitive reaction of parathyroid cells to both the mode of fixation and to fixation media demands careful evaluation of the fixation protocol. This and the polarity of parathyroid ceils have to be borne in mind for estimating secretory activity on the basis of morphological criteria. © 1995 Wiley‐Liss, Inc.
Computer networked scanning electron microscope for teaching, research, and industry applications
Authors: Scott Chumbley L. , Meyer Mitch , Fredrickson Kjell , Laabs Fran
Published: February 2005

A laboratory designed for teaching the operation of a scanning electron microscope (SEM) has been developed. The laboratory makes use of a computer network to allow remote operation of the SEM. Movable teaching stations, consisting of a computer, TV monitor, and joystick control, enable students to view the image on the SEM screen, move the sample, control the basic operating parameters of the microscope, and acquire X‐ray spectra. Images can also be stored on the computers for image analysis or incorporation into reports. The great advantage of the system is that it has been designed to be flexible enough to allow operation from any location that has access to the Internet. The system is relatively inexpensive and uses nonproprietary computer technology available at any computer store. While the laboratory has been designed for teaching, the concept of a multiuser SEM facility that is inexpensive and easy to install should have applications in both industrial and research settings. © 1995 Wiley‐Liss, Inc.
Arc reversal in nonhamiltonian circulant oriented graphs
Authors: Jirásek Jozef
Published: February 2005

Locke and Witte described infinite families of nonhamiltonian circulant oriented graphs. We show that for infinitely many of them the reversal of any arc produces a hamiltonian cycle. This solves an open problem stated by Thomassen in 1987. We also use these graphs to construct counterexamples to Ádám's conjecture on arc reversal. One of them is a counterexample with the smallest known number of vertices. © 2005 Wiley Periodicals, Inc. J Graph Theory 49: 59–68, 2005
2‐factors with prescribed and proscribed edges
Authors: Aldred R. E. L. , Holton D. A. , Sheehan J.
Published: February 2005

Let G be a finite k‐edge‐connected simple graph. We consider when a set of independent edges can be extended to a 2‐factor such that this 2‐factor avoids a fixed set of independent edges. A complete characterization is provided in those cases, where this is feasible. © 2005 Wiley Periodicals, Inc. J Graph Theory 49: 48–58, 2005
Biosynthesis of Polyhydroxyalkanoate (PHA) Copolymer from Fructose Using Wild‐Type and Laboratory‐Evolved PHA Synthases
Authors: Tsuge Takeharu , Yano Kotaro , Imazu Shin‐ichi , Numata Keiji , Kikkawa Yoshihiro , Abe Hideki , Taguchi Seiichi , Doi Yoshiharu
Published: February 2005

Summary: Eleven laboratory‐evolved polyhydroxyalkanoate (PHA) synthases which originated from Pseudomonas sp. 61‐3 enzyme (PhaC1Ps), together with the wild‐type enzyme, were applied for PHA synthesis from fructose using Ralstonia eutropha PHB‐4 as a host strain. The evolved PhaC1Ps mutants had amino acid substitution(s) at position 325 and/or position 481. In these mutants, serine‐325 (S325) was replaced by cysteine (C) or threonine (T), while glutamine‐481 (Q481) was replaced by lysine (K), methionine (M) or arginine (R). All recombinant strains harboring the genes of the evolved PhaC1Ps mutants produced a significantly increased amount of PHA (55–68 wt.‐%) compared with the one harboring the wild‐type gene (49 wt.‐%). Particularly, those evolved PhaC1Ps mutants having multiple amino acid substitutions showed higher activities for PHA synthesis. Characterization of the PHA by NMR spectroscopy revealed that they were copolymers consisting of (R)‐3‐hydroxybutyrate (98–99 mol‐%) and medium‐chain‐length comonomers (1–2 mol‐%). This study also confirmed that amino acid substitution at position 481 in PhaC1Ps led to an increasing molecular weight of PHA. The number‐average molecular weight ($\overline M _{\rm n}$) of PHA ($\overline M _{\rm n}$ = 240 000) synthesized by the evolved PhaC1Ps (Q481K) mutant was 4.6‐fold greater than that ($\overline M _{\rm n}$ = 52 000) synthesized by the wild‐type enzyme.

PHA content in recombinant R. eutropha PHB‐4 expressing the wild‐type or the laboratory‐evolved PHA synthase.

magnified image

PHA content in recombinant R. eutropha PHB‐4 expressing the wild‐type or the laboratory‐evolved PHA synthase.
Cover: Macromol. Mater. Eng. 2/2005
Authors: Pfister Andreas , Walz Uwe , Laib Andres , Mülhaupt Rolf
Published: February 2005

Cover: For the first time zinc polycarboxylate ionomers have been used successfully as a powder material for the rapid prototyping technology 3D Printing™. The resulting 3D models show water resistance, which is rather unique with respect to the conventional materials which are processed using the ZCorporation 3D printers or the Deskmodeler™. Advantageous are also the increased mechanical and dimensional stability of the 3D models printed by means of these new materials.

Further details can be found in the Full Paper by A. Pfister, U. Walz, A. Laib, and R. Mülhaupt* on page 99.
Synthesis of a Novel ABC Triblock Copolymer with a Rigid‐Rod Block via Atom Transfer Radical Polymerization
Authors: Zhang Hailiang , Sun Xiaoyi , Wang Xiayu , Zhou Qi‐Feng
Published: February 2005

Summary: A novel ABC triblock copolymer with a rigid‐rod block was synthesized by atom transfer radical polymerization (ATRP). First, a poly(ethylene oxide) (PEO)‐Br macroinitiator was synthesized by esterification of PEO with 2‐bromoisobutyryl bromide, which was subsequently used in the preparation of a poly(ethylene oxide)‐block‐poly(methyl methacrylate) (PEO‐b‐PMMA) diblock copolymer by ATRP. A poly(ethylene oxide)‐block‐poly(methyl methacrylate)‐block‐poly{2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene} (PEO‐b‐PMMA‐b‐PMPCS) triblock copolymer was then synthesized by ATRP using PEO‐b‐PMMA as a macroinitiator.

ABC triblock copolymer with a rigid‐rod block.

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ABC triblock copolymer with a rigid‐rod block.
Glass Transition Temperature Depression at the Percolation Threshold in Carbon Nanotube–Epoxy Resin and Polypyrrole–Epoxy Resin Composites
Authors: Barrau Sophie , Demont Philippe , Maraval Céline , Bernes Alain , Lacabanne Colette
Published: February 2005

Summary: The glass transition temperatures of conducting composites, obtained by blending carbon nanotubes (CNTs) or polypyrrole (PPy) particles with epoxy resin, were investigated by using both differential scanning calorimetry (DSC) and dynamical mechanical thermal analysis (DMTA). For both composites, dc and ac conductivity measurements revealed an electrical percolation threshold at which the glass transition temperature and mechanical modulus of the composites pass through a minimum.

DC conductivity, σdc, as a function of the conducting filler concentration of the CNT– (▪) and PPy– (○) epoxy resin composites.

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DC conductivity, σdc, as a function of the conducting filler concentration of the CNT– (▪) and PPy– (○) epoxy resin composites.
Diffusion Interface Technique for Determination of Initial Polymerization Kinetics
Authors: Skoumal Miroslav , Cejpek Igor , Cheng Chung Ping
Published: February 2005

Summary: A new procedure for the investigation of initial kinetics in a slurry olefin polymerization with a Ziegler‐Natta catalyst has been developed. It is based on the accurate timing of short polymerizations that result from the immediate start of a reaction between a catalyst separated in an oil phase and the remaining components of the system upon their being mixed together. The polymer samples are suitable for 13C NMR analysis and the number of active sites could be calculated.

Schematic illustration of the oil (catalyst)/heptane (monomer‐cocatalyst) diffusion interface.

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Schematic illustration of the oil (catalyst)/heptane (monomer‐cocatalyst) diffusion interface.
Corticobasal syndrome with novel argyrophilic glial inclusions
Authors: Rippon Gregory A. , Staugaitis S.M. , Chin Steven S.M. , Goldman James E. , Marder K.
Published: February 2005

A 42‐year‐old, left‐handed woman first noted impaired dexterity of the dominant hand, soon followed by dysarthria and cognitive decline. Over a 4‐year period, she developed severe left‐sided apraxia with eventual neglect of the left arm and progressive extrapyramidal signs. Cognitive testing showed progressive executive, visuospatial, fluency, and naming impairment with relative preservation of memory. Single‐photon emission computed tomography demonstrated asymmetric right posterior frontal and superior parietal hypoperfusion. The clinical impression was corticobasal degeneration. At autopsy, severe atrophy was seen in the perirolandic and frontal regions. There was marked neuronal loss and gliosis in the posterior frontal and precentral regions and less severe pathology in prefrontal, temporal, and parietal areas. Mild to moderate gliosis and neuronal loss were also seen in the putamen, globus pallidus, subthalamic, and dentate nuclei. Gallyas silver stain revealed numerous inclusions adjacent to oligodendrocyte nuclei in white and gray matter of affected cortical and subcortical regions. The gracile inclusions were wavy, slender, and stained positively with antibodies to ubiquitin and αB‐crystallin but not to microtubule‐associated proteins (tau, MAP1B, MAP2), tubulin, neurofilaments, glial fibrillary acidic protein, or α‐synuclein. The argyrophilic inclusions identified in this case are distinct from those previously described in neurodegenerative diseases. © 2005 Movement Disorder Society
End‐of‐dose akinesia after a single intravenous infusion of the dopaminergic agonist piribedil in Parkinson's disease patients: A pharmacokinetic/pharmacodynamic, randomized, double‐blind study
Authors: Simon Nicolas , Micallef Joëlle , Reynier Jean‐Charles , Lesourd Monique , Witjas Tatiana , Alicherif André , Azulay Jean‐Philippe , Blin Olivier
Published: February 2005

This randomized, double‐blind trial was designed to define the possible relationship between piribedil plasma concentrations and the decrease of the Unified Parkinson's Disease Rating Scale (UPDRS) motor score or the switch from off to on state after single intravenous infusion. Ten fluctuating patients with idiopathic Parkinson's disease (PD) received escalating doses of piribedil (2–16 mg) and placebo. Starting from 2 mg, piribedil was effective in reducing the motor deficit (UPDRS, motor score) including akinesia at the first evaluation time point of 15 minutes, and in reversing off state of 7 of 10 patients. The doses were equally effective, although the effect was more sustained with the highest dose of 16 mg. Piribedil was well tolerated up to a 16‐mg dose and pharmacokinetics were linear up to the 16‐mg dose. Plasma levels of piribedil were not correlated to the motor score improvement or switch from off→on. In conclusion, a short single infusion of piribedil at 2 to 16 mg was safe and effective in improving motor symptoms, including akinesia, of fluctuating PD patients. © 2005 Movement Disorder Society
Adult‐onset neuronal ceroid lipofuscinosis type B in an African‐American
Authors: Ivan Cristina S. , Saint‐Hilaire Marie H. , Christensen Thomas G. , Milunsky Jeff M.
Published: February 2005

We describe a rare case of adult‐onset neuronal ceroid lipofuscinosis (NCL) type B with probable autosomal dominant inheritance, exhibiting behavioral and cognitive abnormalities and extrapyramidal findings. Ultrastructural examination revealed abundant fingerprint profiles in several cell types. To our knowledge, this is the first reported case of an African‐American with adult‐onset NCL. © 2005 Movement Disorder Society
Endometrial expression of progesterone receptor and uteroglobin genes during early pregnancy in the rabbit
Authors: Gutierrez‐Sagal Ruben , Perez‐Palacios Gregorio , Langley Elizabeth , Pasapera Ana Maria , Castro Ivone , Cerbón Marco Antonio
Published: February 2005

The progesterone receptor (PR) plays a pivotal role in the maturation process of the secretory endometrium, implantation and maintenance of pregnancy in rabbits. To determine the dynamics of PR gene expression and its physiological significance, the endometrial expression of PR and PR mRNA were evaluated and compared with the expression of the progesterone‐regulated uteroglobin (UG) gene during 0–5 days post‐coitus in rabbits. The results of immunoblot experiments indicated the presence of PR in endometrial cell extracts from days 1–4 of pregnancy with maximum PR immunostaining on day 2, followed by a marked diminution until its complete disappearance on day 5. When endometrial PR mRNA content was assessed by Northern blots, the results were similar to those of PR immunostaining, with maximal concentrations on the second day after mating. However, PR mRNA levels were still high on day 3, despite the concomitant decrease in immunostainable PR. Endometrial UG gene expression, on the other hand, exhibited a different time sequence. Thus, the UG content in uterine flushings progressively increased from day 3 after mating, reaching maximal levels on the fifth day. The endometrial UG mRNA content presented a similar profile, as its maximum concentration occurred on days 4–5. The overall results indicate that endometrial PR is down‐regulated at both the mRNA and protein levels, possibly by endogenous progesterone during early pregnancy. The striking observation that maximal expression of endometrial UG gene products occurred when PR and its mRNA are no longer detectable suggests an important role for this progesterone‐binding uterine protein during the preimplantation period. © 1993 Wiley‐Liss, Inc.
Successful vitrification of bovine blastocysts, derived by in vitro maturation and fertilization
Authors: Tachikawa S. , Otoi T. , Kondo S. , Machida T. , Kasai M.
Published: February 2005

Bovine blastocysts were produced through maturation, fertilization, and development in vitro. For vitrification, solutions designated EFS, GFS, and PFS were prepared; these were 40% ethylene glycol, 40% glycerol, and 40% propylene glycol, respectively, diluted in modified phosphate‐buffered saline (PBS) containing 30% Ficoll + 0.5 M sucrose. The embryos were exposed to the solutions in one step at room temperature, kept in the solutions for various times, vitrified in liquid nitrogen, and warmed rapidly. When the embryos were vitrified in EFS solution after 1 or 2 min exposure, the postwarming survival rate, assessed by the reexpansion of the blastocoel, was 74–77%. However, when the exposure time was extended to 3 min or longer, this rate dropped to 7–0%. This reduction was attributed to the toxicity of ethylene glycol. Of the embryos vitrified in GFS solution, 53% survived when they were cooled after 1 min exposure; as the duration of the exposure increased, the survival rate increased, reaching a peak (72%) at 4 min. The rate then decreased gradually with exposure time. In PFS solution, embryos surviving after vitrification were recovered only with 1 min exposure (33%), reflecting the high toxicity of propylene glycol. After vitrification in EFS or GFS solution, two embryos were nonsurgically transferred into each of 14 recipient animals. Of the 14 recipients, ten (71%) became pregnant; two resulted in early stillbirths, four recipients delivered twins (four alive and four stillborn), and two delivered single live calves, demonstrating the effectiveness of this simple vitrification method for the cryopreservation of in‐vitro‐produced bovine blastocysts. © 1993 Wiley‐Liss, Inc.