bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural identification of three types of sensory setae on copepod antennae
Authors: Weatherby T. M. , Lenz P.H. 
Published: June 2020

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.
Morphologic changes in the anteroventral cochlear nucleus of acoustically-deprived gerbil
Authors: Yu Shang-Ming , Du Shian-Jyue 
Published: June 2020

Microcystic lesions are reported as a neurodegenerative disorder in the cochlear nucleus of the Mongolian gerbil. These lesions resemble the spongioform degeneration. Such lesions are large holes, cavities or vacuoles and are also known as the microcysts. The microcysts develop in the neuropil or appear in the neuronal perikarya, degenerated axons and dendrites. The number and size of the microcysts is greatly reduced either by the elevation of auditory thresholds or by the conductive hearing loss induced by ligation of the external auditory canal. Furthermore, absence of the microcysts is found in the old deaf animals. This study was to investigate the morphologic changes in the anteroventral cochlear nucleus (AVCN) of the acoustically-deprived gerbil following the sequence of time courses after ligation of the external auditory canal during postnatal development.The mongolian gerbil, Meriones unguiculatus, had been acoustically deprived on the right side by a surgical ligation of the external auditory canal at postnatal day 12-14.
Automated cell counting of astrocytes on patterned substrates containing aliphatic and charged properties
Authors: Shain W. , Ancin H. , Craighead H.C. , Isaacson M. , Kam L. , Roysam B. , Szarowski D. , Turner J.N. , Turner S.W. 
Published: June 2020

Neural protheses have potential to restore nervous system functions lost by trauma or disease. Nanofabrication extends this approach to implants for stimulating and recording from single or small groups of neurons in the spinal cord and brain; however, tissue compatibility is a major limitation to their practical application. We are using a cell culture method for quantitatively measuring cell attachment to surfaces designed for nanofabricated neural prostheses.Silicon wafer test surfaces composed of 50-μm bars separated by aliphatic regions were fabricated using methods similar to a procedure described by Kleinfeld et al. Test surfaces contained either a single or double positive charge/residue. Cyanine dyes (diIC18(3)) stained the background and cell membranes (Fig 1); however, identification of individual cells at higher densities was difficult (Fig 2). Nuclear staining with acriflavine allowed discrimination of individual cells and permitted automated counting of nuclei using 3-D data sets from the confocal microscope (Fig 3). For cell attachment assays, LRM5 5 astroglial cells and astrocytes in primary cell culture were plated at increasing cell densities on test substrates, incubated for 24 hr, fixed, stained, mounted on coverslips, and imaged with a 10x objective.
Stereology of liver lesions induced by feeding PCB 153 [2,2’,4,4’,5,5’- hexachlorobiphenyl] to the rat
Authors: Peng J. , Singh A. , Ireland W. , Chu I. 
Published: June 2020

Polychlorinated biphenyls (PCBs) are persistent environmental contaminants. A potential health hazard exists for humans and animals because of the PCBs long half-life and capacity to bioaccumulate in the aquatic and terrestrial food chains. The liver is known to be the most significantly affected organ following experimental exposure to PCBs. We have reported the ultrastructure of liver of rats orally administered PCB 153 for 13 weeks. In the present work stereology was applied to estimate measurements of the ultrastructural lesions in the liver.Twelve Sprague-Dawley rats of both genders were distributed into four groups comprising three animals of each gender. Animals in treated groups received diets containing PCB 153 (dissolved in 4% corn oil) at 50,000 ppb concentration; animals in control groups received diets containing corn oil only. The animals were euthanized 13 weeks after the onset of the experiment. Liver specimens were harvested from the animals, fixed in buffered 2% glutaraldehyde and post-fixed in 2% osmium tetroxide.
Effects of nuclear polyhedrosis virus formulations on Lymantria dispar larval peritrophic membrane
Authors: Shields K. S. , Podgwaite J. D. 
Published: June 2020

The peritrophic membrane is a continuous tube that encases the food in the midgut and hindgut of Lepidopteran larvae. It presumably protects midgut cells from abrasion by food particles, and perhaps acts as a barrier to infection. The gypsy moth, Lymantria dispar, is susceptible to a nuclear polyhedrosis virus (LdMNPV), which is transmitted per os. Once ingested, viral occlusion bodies (OB) dissolve in the alkaline midgut, liberating virions that ultimately invade susceptible cells. Recent studies have shown that selected stilbenedisulfonic acid derivatives administered in combination with LdMNPV significantly enhance viral potency, but the precise mode of action is unknown. We tested the effect of the stilbene derivative, Blankophor BBH (Burlington Chem. Co., Burlington, NC), on potency of LdMNPV in gypsy moth larvae, and determined the effects of ingested BBH/LdMNPV combinations on the surface structure of the peritrophic membrane.Newly molted second instar larvae were fed high wheat germ diet overlaid with either water, LdMNPV (102-106 OBs/ml), BBH (0.5%), or LdMNPV + BBH.
Human T-lymphocytes (Jurkat cells) expressing HIV-1 TAT-72: SEM
Authors: Koch J. , Gilloteaux J. , Jamison J. M. , Summers J.L. 
Published: June 2020

The human immunodeficiency virus (HIV-1) is dependent upon the synthesis of TAT for efficient transcriptional activation and replication. Following translocation to the nucleus TAT interacts with a cis-acting TAT-responsive element located between nucleotides +1 to +42 within the HIV- 1 long terminal repeat. This region contains an RNA stem loop structure TAR, which interacts with TAT and cellular proteins to increase transcription 1000 fold.We have transfected human T-lymphocytes with an expression vector containing the HIV-1 LTR driving the synthesis of TAT-72. A stable cell line was generated by selection with G418. Cells were grown on round glass coverslips coated with a solution of fibronectin overnight (at 37°C). In addition, cells on coverslips were fixed with a 3.2% glutaraldehyde buffered solution (0.1M Na cacodylate) for 5 min at room temperature, then 15 min at 4°C, then washed gently in a buffer-sucrose solution. Postfixation was performed with an aqueous mixture containing 1.5% OsO4+ 0.5% RuO4 for 20 min at 18°C.
3-D imaging of respirable size asbestos fibers in rat and human lung tissue
Authors: Rogers R.A. , Antonini J.M. , Lai J. , Ekstein B.A. , Oldmixon E.H. , Ducatman B.S. , Brain J.D. 
Published: June 2020

Pulmonary exposure to natural and artificial fibers can result in serious health impacts to many segments of the occupational work force in the U.S. and worldwide. The toxicological response of a fiber on the respiratory tract depends upon the site at which the fiber makes initial contact, through which it migrates, where it deposits, and the route through which it is cleared. Persistence of fibers in lung tissue influences the severity of lung disease. The pulmonary deposition and clearance of inhaled fibers is a major determinant in understanding the health outcome of environmental and occupational exposures to these materials. Current microscopic methods of fiber analysis result in disruption of fiber orientation relative to lung structures and may influence our understanding of fiber toxicity within lungs.The purpose of this study was to examine the in situ pulmonary fate of respirable fibers in lungs using simultaneous nonspecific fluorescent tissue staining and reflected light confocal microscopy. Serial optical sections were recorded using a Sarastro 2000 confocal laser scanning microscope (Molecular Dynamics, Inc.) optimized for reflected light imaging.
pH dependent gastrin secretion mechanism: an immunocytochemical study
Authors: Galán Torres J.A. , LLorca Gallego A. , González Santander R. , Toledo Lobo M.V. , Martínez Alonso F.J. , Martínez Cuadrado G. 
Published: June 2020

Gastrin secretion is induced by vagal stimuli, local distension, peptides or aminoacid solutions, and Ca2+ concentration both in stomach lumen and blood. However, the cellular and molecular mechanisms of gastrin-release are unknown. We have tested the effects of different pH fixative solutions on gastrin distribution by the immunolabeling of antral gastrin cells (G cells).Samples from different portions of adult dog digestive tract and related glands (salivary glands, liver and pancreas) were embedded in paraffin by conventional methods. Another samples from the antral mucosa of adult dogs and rats were fixed using mixtures of glutaraldehyde and paraformaldehyde at different pH (from 4 to 7,6 pH), and embedded in araldite and Unicryl. For post-embedding immnunocytochemical staining purposes, sections were incubated with pre - diluted policlonal rabbit anti-human gastrin (Zimed Labs.Inc., San Francisco, USA), rinsed in TBS and incubated with a 15 nm gold-conjugated IgG as secondary antibody. These sections were stained with uranil acetate and examined with TEM.
Immunogold localization of β1 integrin in mature avian smooth muscle
Authors: Stromer M. 
Published: June 2020

Integrins are α β heterodimeric transmembrane glycoproteins. The extracellular aminoterminal portion of the dimer contains the ligand-binding region and provides a linkage to the extracellular matrix and to other cells. The relatively smaller cytoplasmic carboxyterminal region interacts with the cytoskeleton and specifically interacts with α-actinin and with talin. Integrins are, thus, thought to be involved in signal transduction at the surface of many cell types. Smooth muscle cells contain α1β1integrin which has been immunolocalized in fibroblast focal contacts. Because aα-actinin and talin are components of attachment plaques which are sometimes referred to as plasma membrane-bound dense bodies in smooth muscle, we used immunogold labeling and transmission electron microscopy (TEM) to determine the location of β1integrin at the smooth muscle cell surface.Strips of smooth muscle from mature chicken gizzards were isometrically clamped and were fixed in 2% paraformaldehyde in modified Krebs Ringer that contained 2mM Ca2+and 2mM Mg2+for 2½ hrs. at 2° C. Fixed strips were cut into 0.5-0.8mm cubes that were immersed in 0.15 M glycine for 1 hr.
Immunogold labeling of the bacterial surface components of shigella flexneri 2a
Authors: Chen D.H. , Wang G.H. , Zhang H.Q. , Li H. 
Published: June 2020

Some bacterial outer membrane components are efficient protective antigens against Shigella spp. Electron microscopic immunogold labeling provides a possibility for investigating the surface exposure of antigens (1). The aim of the present study was to localise surface antigens of Shigella flexneri 2a by using an electron microscopic immunogold labeling technique.Seven monoclonal antibodies (MAbs: 2A3, 3A6,2E6,1G8,1Al and 4F1) used in this study were produced as described previously (2). Pure cultures of Shigella flaxneri 2a were grown in broth, harvested by centrifugation, prefixed and then immunolabelled by MAbs and anti-mouse IgG conjugated to colloidal gold particles (GAMG15 and GAMG5) respectively. Ultrathin sections of labelled bacteial cells were cut and viewed in a transmission electron microscope (Philips EM 400T).Electron microscopic examination of the sectioned organisms showed that gold labeling was confined to the outer surface of the bacterial cell wall. Binding of the MAb on whole bacterial cell indicated the antigens recognized by MAbs 3A6, 2E6, 4F1 and 2A3 were exposed on the outer surface of cell membrane (Fig 1, a-c), and those by MAbs 1A1 and 1G8 were not.
Cytochemical localization of calcium in myoblasts of the chick embryo myotome
Authors: González Santander R. , Toledo Lobo M.V. , Martínez Alonso F.J. , Martínez Cuadrado G. , Gánzalez-Santander Martinez M. , Monteagudo M. 
Published: June 2020

Muscle fibers are derived from multinucleated myotubes which are themselves formed during embryonic development by the fusion of mononucleated myoblasts. Myoblast fusion results from a sequence of different and highly orchestrated stages demonstrated previously in vitro: recognitionalignment, adhesion and membrane fusion. Like many other fusion systems, myoblast fusion is Ca2+- dependent. The role of Ca2+is multiple since it is needed for muscle cell differentiation, for the alignment stage and it has also been demonstrated that Ca2+influx precedes fusion increasing free intracellular Ca2+. It has been proposed that this increase in free intracellular Ca2+may activate an enzimatic cascade which leads to membrane fusion.The present study, using the K-pyroantimonate method, describes Ca2+localization and storage in myoblasts before fusion for the first time, since this method had not been applied to skeletal muscle development studies before. Chick embryos from 51 to 108 h. of incubation (Hamburger and Hamilton stages 16 to 25) were used.
A comparison of the Three-Dimensional structures of Z bands in unstimulated and rigor skeletal muscle
Authors: Schroeter J.P. , Edwards R.J. , Goldstein M.A. 
Published: June 2020

Previous studies (reviewed in ref. 1) lead to the expectation that Z bands from unstimulated skeletal muscle exhibit the unactivated small square form of the Z band lattice. Rigor Z bands, on the other hand are expected to exhibit the basket-weave form of the Z band lattice associated with activation in skeletal muscle. This Z band structural transition has been investigated by three-dimensional reconstruction of Z bands and nearby I bands in unstimulated and rigor rat soleus muscle. The reconstructions were calculated using the tomographic method of weighted back-projection on a series of electron micrographs of longitudinal thin sections of muscle.Examination of Z band cross-sections of the reconstructions reveals that the unstimulated muscle does indeed exhibit the expected small square lattice form. Furthermore, Z band cross sections of the rigor reconstructions reveal the expected basket-weave lattice form. The lattice dimensions were 20 +- 1 nra for the small square lattice and 27 +- 4 nm for the basket-weave lattice, consistent with the results from electron micrographs of cross-sections.
Cryoelectron microscopy and image reconstruction of spherical viruses with spot scan and FEG technologies
Authors: Olson N. H. , Lücken U. , Walker S. B. , Otten M. T. , Baker T. S. 
Published: June 2020

The field emission gun electron microscope (FEG) is a tool that has the potential to achieve near atomic resolution information of biological macromolecules. The FEG provides a beam with higher spatial and temporal coherence and a better phase contrast transfer function than do microscopes with either tungsten or LaB6 filaments. The FEG is also ideal for spot scan imaging applications because it can produce a small, coherent and very bright spot. In spot scan mode the specimen is exposed to an array of nonoverlapping spots rather man a flood beam. This significantly reduces beam-induced specimen drift.Frozen-hydrated samples of cowpea chlorotic mottle (CCMV, Fig. 1A) and cowpea severe mosaic virus (CPSMV, Fig. IB) were examined on a Philips CM12 transmission electron microscope equipped with a standard LaB6 gun and on a Philips CM200 equipped with a field emission gun, respectively. The CM12 was operated at 120kV and was externally controlled by means of a spot scan imaging program which produced a series of 250 nm diameter spots on Kodak SO-163 sheet film.
Ultrastructural and immunocytochemical studies of the extracellular matrix in sea urchin embryos
Authors: Howard Louisa , Spiegel Evelyn , Spiegel Melvin 
Published: June 2020

There is currently a broad interest in the extracellular matrix (ECM) of the sea urchin embryo, but little information about its overall morphology. We are beginning to obtain a detailed view of the structure of the ECM by means of thick section stereoimaging techniques and immunolabeling of Lowicrylembedded thin sections.For thick section images, ruthenium red was used during fixation for better retention of ECM components. 0.38, 0.5 and 1.0μ.m sections were photographed at 100, 200 and 1,000KV respectively. For immunolabeling, embryos were fixed in 1% glutaraldehyde/0.25% paraformaldehyde in 85% seawater containing 0.05M cacodylate buffer, dehydrated and embedded in Lowicryl K4M. Thin sections were incubated with anti-laminin and stained with protein A-colloidal gold (15nm) complex.
3H-galactose and 3H-glucose incorporation into newly synthesized hepatic glycogen in control-fed rats
Authors: Michaels J.E. , Garfield S.A. , Hung J.T. , Smith S.S. , Cardell R.R. 
Published: June 2020

3H-galactose (gal) and 3H-glucose (glu) were compared to determine which compound was preferable for pulse labeling newly formed hepatic glycogen. Control fed rats were used to achieve substantial and consistent levels of hepatic glycogen and to stimulate glycogen synthesis.Rats fed once daily for 4 hr achieved hepatic glycogen levels > 3% wet weight liver prior to injection by tail vein of a tracer dose of 3H-gal or 3H-glu. The rats were sacrificed 15-120 min later and liver was prepared by routine techniques for light (LM) and electron microscopic (EM) radioautography (RAG) and biochemical analysis.
Mechanism of germ cell degeneration in human and guinea pig testes
Authors: Chakraborty J. , Dewri R. , Jhunjhunwala J.S. 
Published: June 2020

The mechanism of germ cell degeneration in the contralateral testes of men with varicocele or torsion of the spermatic cord has not yet been fully elucidated. The major cause of such a gap in our knowledge is due to the lack of a suitable animal model. We used guinea pigs as an experimental animal model, to evaluate the suitability of this animal species to study the testicular pathology.Unilateral torsion of the spermatic cord was surgically induced in 36 animals. Groups of six animals were sacrificed at intervals of 4,8,12,16,20 and 24 months. Pieces of tissues were obtained from the contralateral testis of each animal. Human testicular biopsies were obtained from patients with either torsion of the spermatic cord or varicocele. Tissue specimens were fixed, dehydrated and embedded in epon following the usual procedure.
Acetaminophen: fatty enhanced toxicity
Authors: Poolsawat S.S. , Huerta C.A. , Miranda G.A. , Nguyen L.T. 
Published: June 2020

Drug toxicity accounts for 10%-30% of all medical in-patients admissions; some of the drug induced illnesses often occur following hospitalization. 5%-6% of medical in-patients deaths are initiated or induced by drug intake (1-4); about one-third of these cases are caused by non-prescription drugs. Acetaminophen, considered among the safest of all over-the-counter analgesics, has been reported to induce fatal hepatic necrosis both in man and animals (5-8). Frequently, adverse drug reactions arise from hypersensitivity to a drug and its side effects, or to drug interactions with food and food additives. This study is undertaken to observe the effect of acetaminophen on the liver when a fatty diet is simultaneously administered.Swiss Webster mice were individually gavaged with a 286 mg/Kg dosis of acetaminophen for 4 days; control animals received saline alone. Both groups received rat feed plus 20% fat and were euthanized on the 5th day. Liver tissues were either fixed in 2% gluteraldehyde; post-fixed in 1% osmnium tetroxide in 0.1M sodium cacodylate buffer and embedded in Araldite 502 for TEM; or processed for alkaline phosphatase activity (9).Hepatocyte derived from mice exposed to acetaminophen (Fig. 1) showed increased Golgi Apparatus (GA) and secretory granules (SG) activity. These phenomena appear to be responsible for the elevated alkaline phosphatase activity (Fig. 2) in response to acetaminophen detoxification exerted by the hepatocyte. However, when a fatty diet is incorporated into the study: the hepatocyte exhibited generalized cytoplasmic lysis and increased lipid droplets (Fig. 3), localized coagulative necrosis of the hepatocyte normally found in the caudal and right lobes of the liver (Fig. 4) and increased pynotic hepatocytes (Fig. 5) are noted
Ultrastructure of esophageal epithelium of rats fed Zn-deficient diet
Authors: Yamashiro S. , Bast T. , Bray T.M. , Bettger W.J. 
Published: June 2020

It has been shown that animals fed a Zn-deficient diet developed various epithelial lesions. These include parakeratosis of the tongue, larynx and nasal sinuses in the ducks and hypertrophy of esophageal mucosa in the rats and pigs.Twenty-one weanling, male Wistar rats were equally divided into three groups. Seven rats were fed a diet containing less than 1.1 ppm Zn ad libitum for 3 weeks. Control rats were either pair-fed or fed ad libitum a diet supplemented with 100 ppm Zn. The basal diet was composed of 20% egg white, 10% corn oil, 63.55% glucose hydrate, 1% vitamin premix, 4% mineral premix, 0.25% choline chloride, 0.4% sodium phytate and 0.8% calcium carbonate. Minerals and vitamins additions were according to the AIN-76 recommendations (5).
Inelastic scattering at surfaces and interfaces
Authors: Ritchie R. H. , Howie A. 
Published: June 2020

An important part of condensed matter physics in recent years has involved detailed study of inelastic interactions between swift electrons and condensed matter surfaces. Here we will review some aspects of such interactions.Surface excitations have long been recognized as dominant in determining the exchange-correlation energy of charged particles outside the surface. Properties of surface and bulk polaritons, plasmons and optical phonons in plane-bounded and spherical systems will be discussed from the viewpoint of semiclassical and quantal dielectric theory. Plasmons at interfaces between dissimilar dielectrics and in superlattice configurations will also be considered.