bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ischemia‐Induced delayed‐onset paraplegia is accompanied by an unusual form of synaptic degeneration in the lumbosacral segments: An experimental light and electron microscopic study in dogs
Authors: Marsala Joseph , Marsala Martin , Sulla Igor , Burda Joseph , Galik Jan , Orendacova Judita 
Published: February 2005

AbstractWe studied the effect of high thoracic aorta cross‐clamping, complete transverse section of the spinal cord at Th6 level, and combined hemisection at Th6 level followed later by high thoracic aorta cross‐clamping upon the morphology and number of identified presynaptic knobs in lumbosacral segments in dogs. In animals surviving 48‐72 hours after high thoracic aorta cross‐clamping the occurrence of an unusual form of boutons accompanied by periboutonal halo in L3‐S1 segments was found. According to the bouton size and light as well as electron microscopic appearance, four types, i.e., light giant (T1), dark enlarged (T2), light giant with periboutonal halo (T3), and giant disintegrating (T4) boutons were detected after 48 and 72 hour reperfusion. The appearance of four boutonal types in the lumbosacral segments is caused by spinal cord ischemia secondary to high thoracic aorta cross‐clamping followed by 48 or 72 hour reperfusion. At the end of the sixth reperfusion day no signs of enlarged and giant boutons were detected in L3‐S1 segments. A statistically significant increase of enlarged and giant boutons was noted at the end of the third reperfusion day in comparison with 48 hour survival. After spinal cord transection at midthoracic (Th6) level, followed by 72 hour survival, no such unusual synaptic knobs could be found in L3‐S1 segments. The laminar distribution pattern of T1‐T4 types based on light microscopic analysis and confirmed electron microscopically is characteristic and strictly bound to those spinal cord gray matter layers which serve as main termination sites of the descending cortical, brain stem, as well as long propriospinal projections in the lumbosacral segments (laminae V‐VIII). A statistically significant increase of enlarged and giant boutons was found in the intermediate zone (lamina VII). Hemisection at midthoracic level (Th6) followed later by 30 minute high thoracic aorta cross‐clamping and 48 hour reperfusion caused a marked decrease of enlarged and giant boutons in L3‐S1 segments on the hemisectioned side in comparison with the contralateral one. Large amounts of irregularly arranged round vesicles and tubular profiles were disclosed in the boutonal matrix of T1, T3, and T4 types in L3‐S1 segments of animals subjected to 30 minute high thoracic aorta cross‐clamping followed by 72 hour reperfusion. Accumulation of tubular and membranous materials was invariably seen in the bulbous enlargement of the terminal axonal branch. Therefore, it is reasoned that the ischemia‐induced delayed‐onset paraplegia is closely related to synaptic uncoupling, resulting after ischemia‐reperfusion damage of the spinal cord interneurons acting as postsynaptic neurons for long descending spinal cord afferents of cortical and brain stem origin. © 1994 Wiley‐Liss, Inc.
Structural and functional changes in salivary glands during aging
Authors: Kim Sun‐Kee , Allen Edward D. 
Published: February 2005

AbstractVarious salivary glands in senescent humans and other animals have been examined extensively to characterize the structural and functional changes that occur during aging. Although a wide range of different structural changes, involving both the parenchymal and stromal tissues, have been described, it is unclear how any of these changes affects the function of the salivary glands. One major change in structure is the reduction in the volume of acini with a concomitant increase in the ductal volume. Despite this loss of functional acini, the salivary output and the contents seem to be unaltered, or minimally altered, due to aging. One consistent change observed in many salivary glands of aged animals is the decline in the rate of synthesis of proteins and their messenger RNA (mRNA). However, the salivary acinar cells from aged animals can synthesize secretory proteins at an elevated rate just as effectively as those from their younger counterparts in response to external stimuli, which are known to enhance the rate of protein synthesis. Thus, it appears that the salivary acinar cells, which remain structurally intact during aging, seem to retain their functional efficiency. Furthermore, these acinar cells, although reduced in number, are sufficient in quantity to carry out most of the salivary gland functions. © 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.
Backscatter electron imaging of double immunogold labeled erythrocytes using two primary monoclonal IgM antibodies
Authors: Namork Ellen , Heier Hans Erik 
Published: February 2005

AbstractThe majority of mouse monoclonal antibodies reacting with blood group epitopes on erythrocytes are of the IgM class, have equal light chain type, and are available as culture supernatants only. To study the interrelationship of the blood group antigens, a method is presented which allows double labeling applying two unconjugated monoclonal antibodies of the same class and species. The method comprises two indirect, sequential labelings using mouse IgM anti‐A and anti‐H as primary antibodies and two goat anti‐mouse IgM conjugated to 30 and 20 nm colloidal gold particles as secondary antibodies. After labeling for the first antigen, free binding sites on the primary antibody are blocked by incubation with an unconjugated goat anti‐mouse antibody. The free anti‐species on the secondary antibody, conjugated to 30 nm gold particles, are inactivated by silver enhancement. The silver enhancement also enlarges the gold particle for optimal discrimination between the two particle sizes, which are chosen accordingly. Semiquantitations of double labeled cells from subgroup A2 and A3 were found to be in good agreement with the counts of the corresponding single labelings as well as between experiments, irrespective of which of the two antibodies was applied in the first labeling sequence. The results were in accordance with a reciprocal but nonlinear relationship between the A and H antigens and suggest different affinities of the two antibodies for the epitopes in the subgroups investigated, indicating different biochemistry of the antigen determinants. © 1994 Wiley‐Liss, Inc.
Combined use of immunocytochemical techniques and ligand‐gold complexes for investigation of platelet membrane responses to surface activation
Authors: Escolar Gines , White James G. 
Published: February 2005

AbstractExposure of blood platelets to foreign surfaces results in dramatic changes in physical appearance and conversion from a non‐sticky to an adhesive state. Membrane glycoproteins and cytoskeletal assembly play a pivotal role in these interactions. Cytochemical techniques commonly applied for demonstration of macromolecules in tissues have been used for the localization of target glycoproteins on spread cells. The present review examines different experimental strategies and immunocytochemical techniques that can be combined to better understand the organization of platelet receptors during surface activation. Glycoprotein IIb‐IIIa (GPIIb‐IIIa) was localized by immunocytochemical techniques on fixed, surface‐activated platelets. The distribution of functional fibrinogen receptors expressed on GPIIb‐IIIa was revealed by incubation of fixed platelets with fibrinogen‐gold conjugates (Fgn/Au). The movement of receptor complexes was investigated in additional experiments in which surface‐activated platelets were interacted with Fgn/Au and then fixed at different periods. The overall impression of these observations suggests that fibrinogen receptors on surface‐activated platelets do not redistribute spontaneously and that particulates (gold particles), rather than fibrinogen, may trigger the movement. These results are presented in detail and their significance discussed in the light of current theory. Applications and limitations of such techniques are also discussed. © 1994 Wiley‐Liss, Inc.
Programmed cell death of the normal human neutrophil: An in vitro model of senescence
Authors: Payne Claire M. , Glasser Lewis , Tischler Marc E. , Wyckoff Deborah , Cromey Douglas , Fiederlein Roger , Bohnert Oliver 
Published: February 2005

AbstractThe present study provides experimental data which indicate that the neutrophil is ideal for studying programmed cell death or apoptosis in vitro. Neutrophils can be obtained from human peripheral blood in large numbers with minimal experimental manipulation and are easily separated from other leukocytes, providing nearly pure cell suspensions. The neutrophil life span in vitro is sufficiently short to allow observations to be made within eight hours after experimental manipulation. Neutrophils can also be easily maintained in serum‐free, chemically defined media which can be systematically altered, thereby defining specific variables that influence the apoptotic process. Since the neutrophils do not need an exogenous trigger to undergo programmed cell death, it is also an excellent model to study senescence. It was determined from this study that neutrophils undergo apoptosis most efficiently at 37°C, a temperature requirement for physiologic cell death. Neutrophils undergo apoptosis at a slightly faster rate and maintain membrane integrity better when incubated in a tissue culture medium (e.g., RPMI 1640) compared with a balanced salt solution (e.g., HBBB). Cycloheximide, an inhibitor of protein synthesis, was shown to accelerate apoptosis in a dose‐dependent manner. The presence of Zn++ significantly decreased the rate of apoptosis, whereas the presence of Ca++ and Mg++ had no apparent effect. These studies indicate that the process of senescence, culminating in cell death, is subject to modulation by a variety of agents and experimental conditions. In addition, the ultrastructural features of neutrophils undergoing programmed cell death in vitro were compared in detail to those occurring in vivo and were found to be comparable. © 1994 Wiley‐Liss, Inc.
Cartilage proteoglycans: Structure and potential functions
Authors: Roughley Peter J. , Lee Eunice R. 
Published: February 2005

AbstractHyaline cartilage contains five well‐characterized proteoglycans in its extracellular matrix, and it is likely that others exist. The largest in size and most abundant by weight is aggrecan, a proteoglycan that possesses over 100 chondroitin sulfate and keratan sulfate chains. Aggrecan is also characterized by its ability to interact with hyaluronic acid to form large proteoglycan aggregates. Both the high anionic charge on the individual aggrecan molecules endowed by the sulfated glycosaminoglycan chains and the localization within the matrix endowed by aggregate formation are essential for aggrecan function. The molecule provides cartilage with its osmotic properties, which give articular cartilage its ability to resist compressive loads. The other proteoglycans are characterized by their ability to interact with collagen. They are much smaller than aggrecan in size but may be present in similar molar amounts. Decorin, biglycan, and fibromodulin are closely related in protein structure but differ in glycosaminoglycan composition and function. Decorin and biglycan possess one and two dermatan sulfate chains, respectively, whereas fibromodulin bears several keratan sulfate chains. Decorin and fibromodulin both interact with the type II collagen fibrils in the matrix and may play a role in fibrillogenesis and interfibril interactions. Biglycan is preferentially localized in the pericellular matrix, where it may interact with type VI collagen. Finally, type IX collagen can also be considered as a proteoglycan, as its α2(IX) chain may bear a glycosaminoglycan chain. It may serve as a bridge between the collagen fibrils or with the interspersed aggrecan network. © 1994 Wiley‐Liss, Inc.
Fine structure of Tritrichomonas foetus as seen using cryotechniques
Authors: Benchimol Marlene 
Published: February 2005

AbstractTritrichomonas foetus was studied using different physical and chemical fixation methods such as fast‐freezing (by high pressure, “slam‐freezing,” and jet‐propane), freeze‐substitution, conventional freeze‐fracture and deep‐etching, cryoultramicrotomy, and routine preparation for transmission electron microscopy. The use of fast‐freezing fixation (FFF) proved to be superior in terms of structural preservation due to the rapidity of this fixation compared to that obtained using conventional chemical fixation. The low temperature techniques used here were useful to confirm data already obtained by conventional freeze‐fracture using chemical fixation and cryoprotection, such as the presence of flagellar rosettes and costa structure. Cryoultramicrotomy and slam‐freezing also demonstrated the presence of hair‐like structures projecting out from the protozoan surface. New aspects of organelles of T. foetus were demonstrated. Published 1994 by Wiley‐Liss, Inc.
Nitric oxide synthase containing neurons in the carotid body and sinus of the guinea pig
Authors: Tanaka Koichi , Chiba Tanemichi 
Published: February 2005

AbstractThe morphology and function of the carotid sinus and carotid body have been extensively studied, but our knowledge of their transmitter(s) is still incomplete. Nitric oxide (NO) recently has been identified as a novel messenger molecule in a number of neuronal and non‐neuronal tissues. Nitric oxide synthase (NOS) has been demonstrated in many neurons of the autonomic nervous system. The present study examines the distribution of NOS in the carotid sinus and body. The carotid sinus and body of newborn guinea pigs were removed for histochemical examination of NOS using the NADPH‐diaphorase method. In the carotid body, many nerve fibers enveloping the glomus cells were positive for NOS. In addition, some glomus cells were positive for NOS. In the carotid sinus, NADPH‐d positive fibers were distributed unevenly in the adventitia and media. These results indicate the possibility that nitric oxide plays a role in both arterial chemoreception and baroreception. © 1994 Wiley‐Liss, Inc.
Chemosensitivity, plasticity, and functional heterogeneity of paraganglionic cells in the rat coeliac‐superior mesenteric complex
Authors: Borghini Nadine , Dalmaz Yvette , Peyrin Liliane , Heym Christine 
Published: February 2005

AbstractChemosensitivity and plasticity of paraganglionic cells in the rat coeliac‐superior mesenteric complex (CSMC) were investigated at a basal state of normoxia (21% O2) and after long‐term moderate hypoxia (10% O2, 14 days). Chemical sympathectomy previous to hypoxia was performed to destroy principal ganglionic neurons and thus to allow measurement of the norepinephrine and dopamine content of paraganglionic cells.At the basal state, the CSMC contained dopaminergic (TH+/DBH−) and noradrenergic (TH+/DBH+) paraganglionic cells, the majority being of the noradrenergic type. After 14 days of hypoxia, this ratio was reversed and dopaminergic cells predominated, as indicated by a twofold increase of TH+cells and a twofold decrease of DBH+cells. Biochemically, hypoxia produced an increase in the content (1.6‐fold) and utilization (1.4‐fold) of dopamine as well as a smaller increase in the content of norepinephrine, with no change in its utilization rate. The dopaminergic activation induced by hypoxia persisted after sympathectomy with guanethidine.It is concluded that paraganglionic cells in the CSMC display a chemosensitive function. Furthermore, our findings indicate that paraganglionic cells are differentially affected by hypoxia, depending on their distribution and the nature of their neuromodulators. The alterations induced by hypoxia point out the phenotypic plasticity developed by paraganglionic cells in adaptation to hypoxia and further demonstrate the functional heterogeneity of this autonomic cell population in the rat CSMC. © 1994 Wiley‐Liss, Inc.
Adrenal medulla in neural grafting and neural plasticity
Authors: Hansen John T. , Gash Don M. 
Published: February 2005

AbstractThe recent history of neural transplantation using the adrenal medulla parallels an evolution in our thinking about neural grafting as a therapeutic approach to treat neurodegenerative diseases such as Parkinson's disease. Initially, neural grafting was an approach to study development and regeneration. With the discovery that adrenal chromaffin cell grafts would ameliorate some of the motor deficits associated with the loss of striatal dopamine, adrenal grafts were used to provide dopamine to the dopamine‐depleted striatum. However, subsequent studies showed poor chromaffin cell survival unless trophic factors were present at the site of transplantation. These experiments lead to the appreciation of the complex interactions between neurotrophic factors, inflammatory cytokines, the grafted tissue, and the host brain's response. Thus, we find ourselves again using neural transplantation as an approach to help us better understand central nervous system plasticity and the features this plasticity shares in common with development and regeneration. © 1994 Wiley‐Liss, Inc.
Nitric oxide modulates sympathetic neurotransmission at the prejunctional level
Authors: Addicks K. , Bloch W. , Feelisch M. 
Published: February 2005

AbstractIn spite of accumulating evidence for a modulation of sympathetic neurotransmission by endogenously produced nitric oxide (NO), it remains unclear in which parts of the vascular system and at what level this interaction takes place. The aim of the present study was to investigate the distribution of endothelial and neuronal NO synthase (NOS) along the vascular tree of the heart at the light and electron microscopic level using NADPH‐diaphorase (NADPH‐d) staining as a marker for NOS. In addition, the functional effects of exogenous NO on coronary vascular resistance and cardiac adrenergic nerves was studied using the isolated perfused rat heart as a model. The intraaxonal catecholamine content of adrenergic nerve fibers was visualised and morphometrically assessed by applying glyoxylic acid‐induced histofluorescence. The expression of endothelial NOS in the heart was found to depend on the diameter of the blood vessel. Arteries >100 μm always showed intense staining, whereas staining in smaller arteries and veins was considerably weaker. Smooth‐muscle free vessels were essentially devoid of NADPH‐d activity. In atrial and ventricular myocardium, neuronal NOS localised in autonomic nerve fibers along the entire vascular tree. Ultrastructurally, NADPH‐d staining revealed adjacent localisation of NOS‐positive and ‐negative axons, suggesting an interaxonal modulation of adjacent autonomic nerve fibers by NO. In isolated perfused rat hearts, the intracoronary application of 10−8 M NO produced a marked decrease of coronary perfusion pressure, which was accompanied by a distinct increase in intraaxonal catecholamine levels of intramural adrenergic nerve fibers. These results suggest that the entire vascular system from arteries to veins is under the influence of NO and implies that two independently operating NO‐driven processes are involved in the modulation of blood vessel tone: the well‐known pathway of endothelium‐derived NO acting directly on smooth muscle, and a second indirect pathway that inhibits noradrenaline release from perivascular nerve endings by endothelially or neuronally produced NO. The uneven distribution of endothelial NOS furthermore suggests that the latter mechanism predominates when the size of the blood vessel decreases. © 1994 Wiley‐Liss, Inc.
Light microscopic distribution of some cholinergic markers in the rat and rabbit locus coeruleus and the nucleus angularis grisea periventricularis of the domestic pig (Sus scrofa): A correlative electron microscopic investigation of cholinergic receptor proteins in the rabbit
Authors: Caffé A. R. 
Published: February 2005

AbstractCholinergic modulation of locus coeruleus (LC) neurons evokes a variety of neuronal and behavioural effects. In an attempt to understand the LC cholinergic circuit, several markers has been investigated and compared. (Immuno)‐histochemical and autoradiographic methods have been used on rat, rabbit, and pig tissue. To identify the boundaries of the LC in each of these species, sections through the entire brainstem have been stained for tyrosine hydroxylase. The results that the pig does not possess a LC proper that conforms to the accepted features of this cell group. However, in this location fusiform cells reminiscent of LC interneurons are still present. This group of fusiform neurons has been named the nucleus angularis grisea periventricularis (NAGP).LC cells of the rat and rabbit show strong acetylcholinesterase (AChE) activity. In the pig the NAGP is markedly free from AChE staining. Muscarinic binding sites are densely distributed over the rabbit LC and adjacent region. The rat and rabbit LC neurons synthesise both muscarinic (mAChR) and nicotinic receptor protein (nAChR). In the pig NAGP region mAChR and nAChR positive cell bodies are almost absent, while some nAChR immunoreactive dendrites are present. The light microscopic data in the rabbit have been confirmed by electron microscopic analysis.It is concluded that the general concept of a noradrenergic LC that is present throughout mammals is questionable. At present, choline acetyltransferase immunoreactive terminals that closely correspond to the other cholinergic components in the rat or rabbit LC have not been observed. However, in these species the cholinergic sensitivity of LC cells is mediated via both muscarinic and nicotinic receptors on somata and dendrites. © 1994 Wiley‐Liss, Inc.
A computer‐assisted stereological quantification program: Openstereo
Authors: Abrams Don‐Carlos , Facer Paul , Bishop Anne E. , Polak Julia M. 
Published: February 2005

AbstractAt present, the stereological assessment of histological sections is made possible by the use of manual counting techniques which estimate measurement parameters. These methods are tedious, time‐consuming, and subject to operator error. This paper describes a UNIX‐based computer program, OpenStereo, which was developed to facilitate the quantitative investigation of innervation and vascularity from histological sections. We designed OpenStereo to reduce operator error and increase the efficiency of stereological point counting for volume estimation and intercept counting for surface area analysis. The program was written in the C language for the SunTM Workstation and uses the XView graphics user interface. Digital images, obtained by a variety of modalities, may be processed using stereological point counting, interceptions, planimetry, or thresholding techniques. The program displays selected images in a random fashion for analysis or processing and records the number of manually selected points or interceptions. Delineation of the reference space provides the computer with the data necessary to calculate volume or surface densities. The efficiency of OpenStereo was demonstrated by performing a pilot study on the quantification of innervation in the normal human colon and ileum. This stereological package benefits from the features of the X‐windowing environment and has proved to be suitable for what has hitherto been a tedious and time‐consuming task. © 1994 Wiley‐Liss, Inc.