bluuebunny/crossref_metadata_2025_split huggingface dataset:
mRNA structure, in situ, as assessed by microscopic techniques
Authors: Eberwine James H. , Spencer Corinne , Newell David , Hoffman Andrew R. 
Published: February 2005

AbstractThe secondary and tertiary structure of RNA, in situ, is thought to be involved in distinct functions such as directing association of the RNA with the cytoskeleton, enzymatic activity of some RNAs, and the control of translation. In situ transcription (IST), a procedure by which cDNA is synthesized in situ, has been used to assess mRNA structure in situ using fixed cells or tissues. Distinct banding patterns were noted for mouse and rat POMC. Unique IST banding patterns were observed when an oligonucleotide complementary to a putative POMC stem‐loop structure was used to prime IST. Indeed local changes in banding patterns could be elicited by pharmacological agents which modulate POMC translation. Inhibition of POMC synthesis with NaF or dexamethasone decreased the number of POMC mRNAs in the polysome fractions and increased the intensity of high molecular weight IST‐derived bands. Forskolin, a stimulator of POMC synthesis, had the opposite effect. One mechanism by which translational control is thought to occur is by regulation of ribosome movement down the mRNA by specific binding of cytosolic proteins to RNA structure. Cytosolic protein fractions from AtT20 pituitary cells have been shown to specifically bind to the IST‐predicted RNA structure. These findings suggest that 1) mRNA structure can be assessed in situ, 2) translation may be altered by the secondary and tertiary structure of mRNAs, and 3) a predicted stem‐loop structure exists in situ in the 5′‐end of POMC mRNA. © 1993 Wiley‐Liss, Inc.
Assessment of gene expression and peptide secretion from individual cells
Authors: Wise Phyllis M. , Scarbrough Kathryn , Larson Gregg , Chiu Sufen , Weiland Nancy G. , Lloyd Jonathan M. , Hinkle David A. , Cai Aihua 
Published: February 2005

AbstractWe have developed an assay that allows one to monitor gene expression in and peptide secretion from individual cells. By combining the reverse hemolytic plaque with in situ hybridization, investigators can quantitate simultaneously the level of gene expression and the level of secretion of a peptide. The method can be used in any system in which an appropriate antibody for the reverse hemolytic plaque assay and probes complementary to the mRNA of interest are available. It can be used to monitor the level of mRNA and secretion of the peptide product, or expression of one gene and the secretion of another peptide. In this paper we will describe the major steps of the method. We have used the pituitary lactotroph as a model to demonstrate the power of this technique. However, we believe that this method may be an important approach to answer many questions regarding the cellular and molecular mechanisms that regulate the coupling of peptide secretion and gene expression at the single cell level. © 1993 Wiley‐Liss, Inc.
In situ hybridization in HIV research
Authors: Fox Cecil H. , Cottler‐Fox M. 
Published: February 2005

AbstractIn situ hybridization (ISH) for HIV is an arduous, demanding means of detecting viral genetic material in cells and tissues. Good ISH requires broad technical skills and devotion to controls for every step of the process as well as a critical eye when interpreting results. ISH may be used to detect HIV in three ways: by hybridizing to viral RNA, by hybridizing to proviral mRNA being produced for virion packaging, and by hybridizing to proviral DNA in the cytoplasm or integrated in the nucleus of an infected cell. Here we discuss the technical considerations involved and the problems encountered in using ISH to study the pathobiology of HIV infection. Published 1993 Wiley‐Liss, Inc.
Characteristics of uterine aging
Authors: Mulholland Joy , Jones Carolyn J. P. 
Published: February 2005

AbstractUterine aging is in part responsible for a decline in fecundity which begins in middle age in most mammals. Characteristics of uteri from a variety of animals in middle age and old age are reviewed and the factors which may be responsible for this decline discussed. These include age‐related changes in the hypothalamus, pituitary, and ovaries; loss of number or function of steroid hormone receptors; morphological changes in the uterine epithelium; the accumulation of collagen fibrils in the uterine stroma; and loss or impairment of the decidual response. The ultra‐structural morphology of uterine epithelial, stromal, and decidual tissue from 4 month old and 18 month old Fischer 344 rats is presented and compared. © 1993 Wiley‐Liss, Inc.
Cytokines and growth factors in implantation
Authors: Haimovici Florina , Anderson Deborah J. 
Published: February 2005

AbstractA variety of cell types at the blastocyst implantation site produce cytokines and growth factors that could play an important role in the implantation process. Furthermore, receptors for cytokines and growth factors have been detected on embryonic and trophoblastic cells. The purpose of the article is to review the published literature on the effect of cytokines and growth factors on implantation events, and to present recent data from our laboratory on effects of growth factors and cytokines on mouse blastocyst implantation events in vitro. © 1993 Wiley‐Liss, Inc.
A method to detect variations in the wetting properties of microporous polymer membranes
Authors: de la Parra Robin E. 
Published: February 2005

AbstractWith the ability to perform dynamic experiments in the environmental scanning electron microscope (ESEM), the evaluation of microporous polymer membranes via a scanning electron microscope has advanced beyond morphological and elemental analysis. By adjusting sample temperature and environmental chamber pressure, the process of condensing water onto the porous membrane surface can be achieved. In doing so, assessments about the uniformity of wetting in hydrophilic membranes can be obtained based on how the liquid water spreads. Variations in the shape of condensed water droplets formed on non‐water wetting structures will reflect the degree of hydrophobicity. This technique has proven useful in the characterization of hydrophobic spots on chemically modified hydrophilic structures and the dynamic examination of irregular wetting patterns in naturally hydrophilic membranes. © 1993 Wiley‐Liss, Inc.
The esem used to image crystalline structures of polymers and to image ink on paper
Authors: Rask James H. , Flood John E. , Borchardt John K. , York Greg A. 
Published: February 2005

AbstractThis article describes two cases in which the advantages of the ESEM have been exploited in unanticipated ways. First, we have found that etching occurs as the electron beam scans the surface of uncoated polymers in the ESEM. The surface topography caused by this etching, as seen in ESEM images, reflects the morphology of crystalline structures in the polymers. This technique has been valuable in the study of such textures in polymers. The second application is related to our use of the ESEM in support of research on the deinking of paper. In this effort we have learned that an unconventional contrast mechanism can be used during ESEM imaging to distinguish between inked and non‐inked areas of newsprint. Under usual operating conditions, ESEM imaging does not distinguish between inked and non‐inked areas. However, at relatively low sample chamber pressures the non‐inked areas appear brighter than inked areas in ESEM images. © 1993 Wiley‐Liss, Inc.
Environmental scanning electron microscope (ESEM) evaluation of crystal and plaque formation associated with biocorrosion
Authors: Geiger Steve L. , Ross Timothy J. , Barton Larry L. 
Published: February 2005

AbstractThe biofilm attributed to Desulfovibrio vulgaris growing in the presence of ferrous metals was examined with an environmental scanning electron microscope. This novel microscope produced images of iron sulfide colloids and other iron containing structures that had not been reported previously. A plaque composed of iron sulfide enveloped the surface of the corroding metal while crystals containing magnesium, iron, sulfur, and phosphorus were present in the culture where corrosion was in progress. A structure resembling the tubercule found in aerobic corrosion was observed on stainless steel undergoing biocorrosion and the elements present in this structure included sulfur, iron, chloride, calcium, potassium, and chromium. © 1993 Wiley‐Liss, Inc.
Copper/Solder intermetallic growth studies
Authors: Kirchner Kevin W. , Lucey George K. , Geis James 
Published: February 2005

AbstractCopper samples, hot solder (eutectic) dipped and thermally aged, were cross‐sectioned and placed in an environmental scanning electronic microscope (ESEM). While in the ESEM the samples were heated for ∼ 2.5 h at 170°C to stimulate the growth of additional Cu/Sn intermetallic compound. The intent of the study was to obtain a continuous real‐time videotape record of the diffusion process and compare the observations to static SEM images reported to represent long‐term, naturally aged intermetallic growth. The video obtained allows the observation of the diffusion process and relativistic growth phenomena at the Cu, Cu3Sn, Cu6Sn5, and solder interfaces as well as effects on the bulk Cu and solder. Effects contrary to earlier reports were observed; for example, growth rates of Cu3Sn were found to greatly exceed those of Cu6Sn5. © 1993 Wiley‐Liss, Inc.
Copper thick film sintering studies in an environmental scanning electron microscope
Authors: Link Leslie F. , Gerristead William R. , Tamhankar Satish 
Published: February 2005

AbstractThe significance of the ElectroScan environmental scanning electron microscope (ESEM) as a processing tool for studying dynamic morphological changes under controlled temperature/atmosphere conditions was evaluated. The ability to observe dynamic processes in situ, which cannot be achieved by other means, is critical to understanding microstructural formation.Processing of printed copper thick films on ceramics was used as a test case, wherein morphological changes associated with the steps of organic binder removal and sintering of copper particles were observed/examined in real time. Good agreement was seen between microstructures obtained in the ESEM and those achieved in a belt furnace when similar process variables were used. When processed in atmospheres which were proven to induce sintering in a conventional belt furnace, sintering was evident in both cases, and the microstructural changes were documented on videotapes in real time. Determination of critical event temperatures was achieved—that is, binder burnout occurring between 270° and 350°C, onset of oxidation at 520°C, and sintering starting at 770°C.It was thus verified that the microstructural changes during the copper thick film sintering process can be observed in situ using an ESEM. © 1993 Wiley‐Liss, Inc.
Evidence for stimulus access to taste cells and nerves during development: An electron microscopic study
Authors: Mbiene Joseph Pascal , Farbman Albert I. 
Published: February 2005

AbstractWe have examined developing taste buds in fungiform papillae of rats from the 18th day of gestation (E18) to the 15th postnatal day (P15). Nerve processes were seen in the epithelium of E18 rats before taste buds were obvious. At E20, early taste buds were visible, but were embedded within the epithelium, i.e., their cells were shielded from the oral cavity by overlying squamous epithelium. At this stage, the epithelium on the lateral aspects of the fungiform papillae was keratinized, but that overlying the taste bud was not. Some taste bud cells at E20 contained synapse‐like structures near their contacts with nerve processes. In postnatal animals, keratinized epithelial cells were seen overlying taste buds, but taste pores were not observed until P10. How, then, do stimuli reach the taste cells and elicit physiological and behavioral responses as reported by others? The keratinized epithelium overlying the buds was unlike that on the lateral aspect of the papilla in at least one significant way. Few lamellated bodies were present in intercellular spaces beneath the stratum corneum, whereas these were abundant in the corresponding location within epithelium on the slope of the papilla. Although some were present within the squamous epithelium overlying the bud, they apparently were not released into the intercellular space. These lipid‐rich lamellated bodies are thought to represent the water barrier of the epithelium, i.e., the barrier which prevents aqueous solutions from passing through the epithelium. We determined that the keratinized epithelium overlying the taste bud was permeable to a tracer, lanthanum nitrate, whereas that on the lateral surface was not. Lanthanum was visualized around taste cells and around nerve profiles within and near the taste bud. We propose that the absence of an aqueous permeability barrier in the epithelium overlying taste buds likely explains the ability of tastants to reach the taste bud cells and nerves in the developmental period before pore formation. © 1993 Wiley‐Liss, Inc.
Pre‐ and postnatal development of rabbit foliate papillae with special reference to foliate gutter formation and taste bud and serous gland differentiation
Authors: Fujimoto Sunao , Yamamoto Koji , Yoshizuka Mitsuaki , Yokoyama Mitsuru 
Published: February 2005

AbstractThe epithelial downgrowth arises in the presumptive foliate papilla region of the tongue approximately at prenatal day 22, and the distal portion of the primary epithelial cell cords transforms to the bifurcated serous gland and excretory duct between prenatal day 30 and postnatal day 2. The excretory ducts extend upward through the primary epithelial cell cords at rather random intervals and are open to the tongue surface between postnatal days 1 and 2. In this process, successive connections between the adjacent ascending excretory ducts occur mainly due to desquamation of the keratinized lining cells of the ducts, resulting in the formation of the foliate gutter.Taste bud primordia appear in the primary epithelial cell cords by nerve penetration through the basal lamina from prenatal day 30 and nearly fully formed taste buds facing the ascending excretory ducts have been already observed before the foliate gutter formation is completed.In the differentiation process of chemoreceptor (type III) cells from less‐differentiated basal (type IV) cells, subsurface cisterns of endoplasmic reticulum are occasionally present where nerve endings make contact. Since subsurface cisterns have been considered to be involved in reciprocal or efferent synaptic transmission, it is reasonable to consider that these morphological specializations may take a role in neurotrophic signals for differentiation of the chemoreceptor cells. © 1993 Wiley‐Liss, Inc.
Morphometric and immunocytochemical assessment of fungiform taste buds after interruption of the chorda‐lingual nerve
Authors: Oakley Bruce , Lawton Anne , Riddle David R. , Wu Lan‐Hsin 
Published: February 2005

AbstractUnilateral interruption of the chorda‐lingual nerve led to a loss of most epithelial axons and to the deterioration of fungiform taste buds in the anterior portion of the tongue of albino rats, mongolian gerbils, and golden hamsters. By three weeks after surgery the following percentages of fungiform taste buds had completely disappeared: 71% in gerbils, 28% in rats, and 26% in hamsters. Residual taste buds were classified into two groups: atrophic taste buds and taste bud remnants. Atrophic taste buds were smaller than normal and typically had no visible taste pore, although they retained the characteristic oval shape of a taste bud and numerous elongated cells. Taste bud remnants were non‐oval fragments of taste buds with few elongated cells. Specific markers for elongated taste cells (monoclonal antibodies to keratin 19) confirmed that atrophic taste buds, as well as some taste bud remnants, had elongated taste cells. By 180 days after chorda‐lingual nerve transection, 44% of rat fungiform taste buds had disappeared; morphometric analysis of the 311 residual taste buds established that 241 atrophic taste buds and 69 taste bud remnants were, respectively, 50% and 75% smaller than the average volume of 480 normal taste buds. The aggregate loss of gustatory tissue, calculated from the shrinkage of residual taste buds and the volume lost by the outright disappearance of many taste buds, was 88% for gerbils, 72% for rats, and 65% for hamsters. Evaluation in gerbils of the co‐occurrence of taste buds and axons suggests residual taste buds were neurotrophically supported. Every gerbil fungiform papilla that lacked axons lacked a taste bud. Every fungiform papillae that had a residual taste bud had axons; axons were absent from 22% of empty fungiform papillae. Diminished numbers of gustatory neurotrophic axons could account for both the loss of fungiform taste buds and the reduced volume of residual taste buds. © 1993 Wiley‐Liss, Inc.
Organization of the nucleus of the solitary tract in the hamster: Acetylcholinesterase, NADH dehydrogenase, and cytochrome oxidase histochemistry
Authors: Barry M. A. , Halsell C. B. , Whitehead M. C. 
Published: February 2005

AbstractThe distribution of acetylcholinesterase (AChE), NADH dehydrogenase (NADHd), and cytochrome oxidase (CO) was determined in the nucleus of the solitary tract (NST) in the golden hamster. Histochemical staining was compared to cytoarchitectonic subdivisions of the NST (Whitehead: J. Comp Neurol. 276:547–572, 1988) and to terminal fields of primary afferents of the nerves that innervate the tongue. These three histochemical methods resulted in differential staining patterns within the NST that were related to certain subdivisions. Transganglionic transport of horseradish peroxidase (HRP) was used to determine the central projections of the chorda tympani (CT), the lingual branch of the trigeminal (L‐V), and the lingual‐tonsilar branch of the glossopharyngeal nerves (L‐IX). Alternate or the same brain sections were processed to reveal transported HRP, and NADHd or AChE levels. Increased staining of the neuropil with NADHd and AChE was coincident with the dense part of the afferent terminal fields of all three nerves in the NST and the laterally adjacent dorsomedial part of the spinal trigeminal nucleus. CO showed this pattern only for the most rostral part of the CT field. The densest AChE staining coincided with gustatory afferent terminal fields. The histochemical staining facilitated the interpretation of the organization of the NST. For example, at caudal levels of the gustatory NST, it is suggested that taste processing is localized predominately in the medial part of the rostral central, and somatosensory processing in the rostral lateral subdivision. AChE or NADHd staining should facilitate studies of connections, topography, and neuroplastic changes of the gustatory NST. © 1993 Wiley‐Liss, Inc.
Advantages of digitonin extraction to reveal the intracellular structure of rat glomerular podocytes for high‐resolution scanning electron microscopy
Authors: Temkin Robert J. , So Derek Y. F. , Lea Peter J. 
Published: February 2005

AbstractKidneys of anesthetized rats were perfused with digitonin to extract cytosolic proteins of glomerular podocytes so that the remaining intracellular structures could be examined by three‐dimensional stereo high‐resolution scanning electron microscopy (HRSEM). Cytoskeleton, consisting of microtubules and intermediate filaments, was preserved with each applied concentration of digitonin. High concentrations of digitonin (1.0 mg/ml) produced a corrugated appearance in plasma membranes likely due to the formation of digitonin‐cholesterol complexes. At 1.0 mg/ml digitonin, the Golgi complex became vesicularized, and mitochondria were well extracted and their ultrastructure preserved. Lower concentrations of digitonin (0.1 and 0.2 mg/ml) were less disruptive to both the plasma membrane and the Golgi complex. Mitochondria, rough endoplasmic reticulum, coated vesicles, nuclear membrane, and chromatin were well preserved. Extraction with digitonin, at the optimal concentration and perfusion time, simultaneously maintains both the cytoskeleton and membranous organelles inside the cell and provides a method to elucidate the interactions between these two components. Furthermore, digitonin extraction should preserve antigenic sites, thereby allowing the localization of intracellular proteins by backscattered electron imaging of immunogold labels in the scanning electron microscope. © 1993 Wiley‐Liss, Inc.
Ontogeny of platelet‐derived growth factor receptor in fetal rat lung
Authors: Han Robin N. N. , Liu Jason , Tanswell A. Keith , Post Martin 
Published: February 2005

AbstractThere is increasing evidence that platelet‐derived growth factor (PDGF) or PDGF‐like molecules play a role in fetal lung morphogenesis. Our previous studies demonstrated the presence of PDGF‐AA and PDGF‐BB homodimers in fetal rat lung. To study further the target cells of PDGF in lung development, immunolocalization studies of PDGF receptors (PDGFR) were conducted on embryonic and fetal rat lung from day 13 to day 21 of gestation (term = 22 days) using two polyclonal PDGFR antibodies, one of which one recognizes both α and β receptors (PDGFR‐α/β), while the other is specific for the β receptor (PDGFR‐β). A similar immunostaining pattern for both antibodies was noted. Immunoreactivity to PDGFR was evident in both epithelial and mesenchymal cells of the embryonic lung bud as early as 13 days gestation. The number of PDGFR immunoreactive cells increased with advancing gestation. Intense immunoreactivity was noted in both epithelial cells and interstitial cells during the saccular stage of lung development. The immunoreactivity to PDGFR was localized to the apical/luminal side of bronchial and distal airway epithelial cells. PDGFR‐immunopositive bronchial and vascular smooth muscle cells were detected only during the canalicular and saccular stages of lung development. Immunopositive endothelial cells lining the internal vascular plexuses were observed from days 14–16 of gestation. No PDGFR was detected in endothelial cells of large pulmonary vessels. We conclude that PDGFR are present in airway epithelial cells, interstitial cells, and bronchial and vascular smooth muscle cells and that gestation‐dependent up‐ and down‐regulation of PDGFR may play a role in developmental regulation of PDGF bioactivity during lung morphogenesis. © 1993 Wiley‐Liss, Inc.
Pathology of the salivary glands: The contribution of electron microscopy
Authors: Dardick Irving , Burford‐Mason Aileen P. 
Published: February 2005

AbstractElectron microscopy has a limited role in the diagnosis of primary salivary gland tumors, although it can be helpful in metastatic lesions of possible salivary gland origin. The diversity of subtypes in salivary gland tumors, as well as the range of histomorphology within any one subtype, is unparalleled in any other human tumor. This and their relative infrequency causes diagnostic problems for pathologists. Ultrastructural techniques have been of major importance in determining the inter‐relationship of these tumors for classification purposes, revealing the subtle variations in common cellular differentiation pathways, determining the organization of tumor cells, and displaying the importance of extracellular matrix materials in establishing diagnostic criteria for each of the many subtypes. Electron microscopy has also been valuable in non‐neoplastic salivary gland disease and has an increasing role in experimental studies involving tissue from human and animal salivary parenchyma. © 1994 Wiley‐Liss, Inc.