bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of ornithine decarboxylase in monolayer cells treated with trypsin
Authors: Gerner Eugene W. , Glass James R. , Fuller David J. M. 
Published: May 2005

AbstractWhen monolayer Chinese hamster cells are treated with trypsin for short periods of time, ornithine decarboxylase (ODCase) activity increase two‐ to fourfold. This increase can be blocked by aprotinin, a protease inhibitor, and is not observed when cultures are dislodged from substrate mechanically prior to contact with exogenous trypsin. The trypsin‐induced increase in ornithine decarboxylase activity is not due to degradation of enzyme or inhibitor molecules or to new enzyme synthesis. Immunoprecipitable protein, radiolabeled with [3H]α‐difluoromethylornithine in vitro, is the same molecular weight in cells harvested with or without trypsin. Protein‐bound levels of this specific enzyme‐activated irreversible inhibitor of ornithine decarboxylase are unchanged by trypsin treatments that increase enzyme activity. Trypsin treatment of rat embryonic fibroblasts, transformed by a temperature‐sensitive mutant of Rous sarcoma virus, increases ODCase activity in cells growing at the nonpermissive, but not at the permissive, temperature for the transformed phenotype. These results suggest that ornithine decarboxylase can be activated by exogenous trypsin treatment in a manner that is dependent on cell adhesion properties, which are modified in transformed cells.
On the role of 17 alpha‐estradiol and 17 beta‐estradiol in the proliferation of MCF7 and T47D‐A11 human breast tumor cells
Authors: Papendorp John T. , Schatz Robert W. , Soto Ana M. , Sonnenschein Carlos 
Published: May 2005

AbstractA comparative study of the proliferative effect of 17 beta‐estradiol and 17 alpha‐estradiol on human estrogen‐sensitive cell lines was performed. When using charcoal‐dextran stripped human female sera‐supplemented media the administration of the hormones, 17 alpha‐estradiol at 3 × 10−10M, and 17 beta‐estradiol at 3 × 10−11M, resulted in a ten‐fold increase in cell yield when compared with non‐estrogen supplemented controls after cells were grown for periods between 10 to 14 days. No significant metabolization of 17 alpha‐estradiol into 17 beta‐estradiol occurred as measured by the E2 levels in the supernatants of the cell culture flasks. Increased concentrations of 17 beta‐estradiol and 17 alpha‐estradiol added to the media bathing C7MCF7‐173 cells resulted in a triggering of a partially successful shut‐off effect; this phenomenon was not observed with T47D‐All cells. These results are compatible with predictions stemming from the indirect and direct negative working hypothesis for the regulation of cell proliferation.
Detector Systems in Capillary Gas Chromatography
Authors: Noij Th. , Rijks J. A. , van Es A. J. , Cramers C. A. 
Published: May 2005

AbstractExpressions for the minimum detectable amount Qo and the minimum analyte concentration Co as functions of the chromatographic parameters are derived for both mass and concentration sensitive detectors. The effects of pressure drop, column inner diameter, and film thickness are given.The minimum analyte concentration for mass flow sensitive detectors, Com, can be reduced considerably by selecting the carrier gas velocity well above its optimum value (related to Hmin), however, at the cost of long columns and long analysis times. For Qo the improvements can be neglected, and so the analysis can best be performed at uopt.When the flow rate in the detector, Fd, is equal to the column flow rate Fc, the maximum permissible detector volume of concentration sensitive detectors is proportional to dc2 up to dc3, and so narrow bore columns require detectors of extremely small volume. Make‐up gas has to be added when the actual volume is too large, thus worsening the detectability. Another approach, vacuum operation of the detector cell, appears to be very attractive. On the other hand, when wide bore columns are used in combination with small volume concentration sensitive detectors, very small values of Qoc and Coc are obtainable when the abundant carrier gas can be removed before entering the detector cell.Digital noise filtering can further reduce the obtainable Qo and Co values, especially for broad peaks and thus for wide bore columns.
Supercritical fluid chromatography of alkylene oxide‐fatty alcohol condensates: Their quantitation in water samples
Authors: Onuska F. I. , Terry K. A. 
Published: May 2005

AbstractA method is described for the quantitative determination of linear alkylene oxide‐fatty alcohol condensates, nonionic surface active agents in water. Surface active agent is extracted from water samples with benzene. Surfactant is further extracted by salting out into chloroform. Capillary, supercritical fluid chromatography allows the separation and quantitative determination of oligometric constituents using carbon dioxide as a supercritical fluid. In this case, a fingerprint of the surfactant is obtained. Analysis time, however, is approximately 60 minutes. In the second case, the ether groups of ethylene oxide fatty alcohol condensates are cleaved by reaction with 50 percent hydrobromic acid in glacial acetic acid in sealed ampoules. The resulting alkyl bromides are extracted with carbon disulfide and chromatographed by both the supercritical fluid, capillary column chromatography (SFC) and high resolution open tubular column gas chromatography (OTC – HRGC). Results are in good agreement between these two techniques.
Siloxane/silarylene copolymers as stationary phases for capillary gas chromatography. Part II: Phenylsubstituted polymers
Authors: Bemgård A. , Blomberg L. , Lymann M. , Claude S. , Tabacchi R. 
Published: May 2005

AbstractA commercially available silanol terminated silicone stationary phase, OV‐61‐OH (33% phenyl), and two phenyl‐substituted siloxane/silarylene copolymers, Sila 3 (27% phenyl) and 4 (35% phenyl), have been evaluated for use as stationary phases in fused silica capillary columns for gas chromatography.Ulterations in column adsorptive activity, separation efficiency, stationary phase film thickness and selectivity after column conditioning for 50 h at 370°C have been studied. A high thermal stability was experienced with the stationary phases tested here. For OV‐61‐OH, the best thermal stability was obtained when coated on untreated fused silica, which illustrates the importance of grafting reactions here. The heat treatment resulted in some deactivation of adsorptive sites in the column. A higher degree of column deactivation was achieved when surface silylation was performed prior to coating. High thermal stability was achieved with Sila 3 when coated on such surfaces. Sila 3 would thus be preferred in cases when high thermal stability in combination with high dsorptive inertness is desired.Sila 4 showed low column bleeding at 370 °C, but prolonged heating at this temperature resulted in the broadening of n‐alkane peaks when eluted at 90 °C. This indicates that excessive crosslinking has taken place during the heat treatment and the minimum allowable column operation temperature is thereby increased to ca. 120 °C. The separation of aza‐arenes and of triglycerides are
shown as applications.
Ultrastructural and histochemical features of the thymus glands of the adult lungless salamander, Plethodon glutinosus (Caudata: Plethodontidae)
Authors: Curtis Sherill K. , Cowden Ronald R. , Nagel Jerry W. 
Published: May 2005

AbstractThe thymus glands of adult slimy salamanders (Plethodon glutinosus) were examined by light and electron microscopy with the objective of describing the populations of epithelial cells believed to be secretory. The results of various histochemical procedures designed to demonstrate nucleic acids, proteins, lipids, and mucosubstances were evaluated by light microscopy. Each thymus is incompletely subdivided into a variable number of interconnected lobules by trabeculae extending inward from a thin capsule composed of connective tissues. The thymic parenchyma lacks distinct cortical and medullary regions, although developing lymphocytes and plasma cells tend to accumulate in larger numbers in the outermost portions of the gland. Basophils are found regularly in the capsule and trabeculae, but only very rarely within the thymic parenchyma. The epithelial cells of the thymus can be classified into five categories: epithelial reticular cells; three varieties of granulated cells (types I, II, and III), and myoid cells. Epithelial reticular cells form a three‐dimensional network which extends throughout all portions of the thymus. Type I and type II granulated cells can be distinguished from one another by various morphological criteria at the ultrastructural level, but only small differences in the composition of their inclusions can be demonstrated histochemically. Both types of granules are composed principally of a proteinaceous material containing an abundance of primary amino and guanidyl groups. In addition, most type I inclusions possess a lipid component that cannot be demonstrated in type II granules. Type III granulated cells possess very small cytoplasmic inclusions resembling those of gastroenteric endocrine cells. Myoid cells contain concentrically arranged myofibrils composed of sarcomeres. In favorably oriented material, small cysts can be identified whose walls are composed of mixtures of type I cells, type II cells, and epithelial reticular cells. Groups of degenerating epithelial cells form lamellated structures corresponding to Hassall's (thymic) corpuscles.
Fine structural studies of the nervous system and the apical organ in the planula larva of the sea anemone Anthopleura elegantissima
Authors: Chia Fu‐Shiang , Koss Ron 
Published: May 2005

AbstractThe nervous system of the planula larva of Anthopleura elegantissima consists of an apical organ, one type of endodermal receptor cell, two types of ectodermal receptor cells, central neurons and nerve plexus. Both interneural and neuromuscular synapses are found in the nerve plexus.The apical organ is a collection of about 100 long, columnar cells each bearing a long cilium and a collar of about 10 microvilli. The cilia of the apical organ are twisted together to form an apical tuft. The ciliary rootlets of the apical organ cells are extremely long, reaching to the basal processes of the cells adjacent to the mesoglea.All three types of sensory cells are tall and slender in profile and are identified by the presence of one or more of the following features: microtubules, small vesicles, membrane‐bound granules and synapses. The interneurons are bipolar cells with somas restricted to the aboral end, adjacent to the apical organ. All synapses observed are polarized or asymmetrical.A diagram including all the elements of the nervous system is presented and the possible functions of the nervous system are discussed in relation to larval behavior.
A morphometric study of the cochlea of the little brown bat (Myotis lucifugus)
Authors: Ramprashad Fred , Landolt Jack P. , Money Kenneth E. , Clark Diana , Laufer Jerry 
Published: May 2005

AbstractA detailed morphometric study of the basilar membrane was made from serial sections and graphic reconstructions of the cochlea of three little brown bats. Four distinct morphometric changes were observed within the basilar membrane. First, between 0‐1.4 mm from the basal end of the cochlea, there is a rapid increase in width and cross‐sectional area of the basilar membrane. Secondly, between 1.4‐2.5 mm, there is little change in width of the basilar membrane (its cross‐sectional area is at its greatest in this region). Thirdly, between 2.7‐3.1 mm, there is a sudden decrease in cross‐sectional area concomitant with an increase in the width of the basilar membrane. Finally, between 3.1 mm and the apex, there is a gradual decrease in cross‐sectional area concomitant with an increase in the width of the basilar membrane. The magnitudes of the cross‐sectional areas of the scalae media and vestibuli decrease from base to apex, but this is not true for the scala tympani. The cross‐sectional area of the scala tympani appears to decrease from the base to 0.7 mm, then it increases up to 1.4 mm, and then it decreases to the apex. These morphometric changes in the basilar membrane of the little brown bat are compared to those in other echolocating and non‐echolocating mammals. The significance of these changes is discussed in relation to the range of hearing in the little brown bat.
Normal distribution of alpha‐1‐adrenoceptors in the rat spinal cord and its modification after noradrenergic denervation: A quantitative autoradiographic study
Authors: Roudet C. , Savasta M. , Feuerstein C. 
Published: May 2005

AbstractThe distribution of alpha 1 (α1)‐adrenoceptors along the different segments of the spinal cord (cervical, thoracic, lumbar, and sacral) of normal rats has been studied by quantitative autoradiography using the specific α‐antagonist [3H]Prazosin as a ligand. In addition, the influence of noradrenergic (NA) denervation [obtained either by complete transection of the spinal cord at vertebrae level T8‐T9 or by selective lesion of NA spinal cord system carried out by intracisternal injection of 6‐hydroxydopamine (6‐OHDA)] on eventual variations of α1‐adrenoceptor density at spinal cord target cells was studied in parallel.In control rats, the quantitative analysis of α1‐adrenoceptor densities revealed a widespread distribution of these receptors along all segments of the spinal cord with a similar pattern in the various subregions of gray matter studied. This distribution of α1‐adrenoceptors was quite well correlated with the distribution of NA terminals, when referring to previous descriptions by immunohistochemistry.After 6‐OHDA lesion, as well as caudally to the transection, a significant increase of α1‐adrenoceptor densities was observed in all spinal subregions thus evidencing supersensitivity.These results suggest that NA may act in the spinal cord, at least partly, via α‐adrenoceptors and that the expression of these receptors could be influenced by NA dysfunction, as demonstrated here through the effects observed in lesioned animals. © 1993 Wiley‐Liss, Inc.
Early dendrite development in spinal cord cell cultures: A quantitative study
Authors: Neale Elaine A. , Bowers L. M. , Smith T. G. 
Published: May 2005

AbstractNeurons in dissociated cell culture provide a favorable system for the quantitative analysis of structural changes and the examination of structure‐function relationships during development. Fragment C of tetanus toxin was used to label neurons in murine spinal cord cell cultures and dendrite outgrowth was monitored by a number of measures. The dissociated neurons increased in morphologic complexity from approximate spheres to highly branched structures during the first week in culture. Much of the structural complexity of the dendrite arbor, as quantified by fractal dimension, was established within 48 hr after plating, i.e., prior to the development of interneuronal contacts. During the first few days in culture, dendrite branching complexity increased more rapidly than dendrite size, whereas after 4 days, fractal dimension remained relatively constant while dendrites continued to grow. Fractal analysis has provided data which suggest that the early development of dendrite branching complexity is determined intrinsically. Fractal dimension, as an effective index of morphologic complexity, should be a useful tool for the further study of extrinsic signals which might modify the generation or stabilization of dendrite form. © 1993 Wiley‐Liss, Inc.
Versican, a hyaluronate‐binding proteoglycan of embryonal precartilaginous mesenchyma, is mainly expressed postnatally in rat brain
Authors: Bignami A. , Perides G. , Rahemtulla F. 
Published: May 2005

AbstractThe localization of versican, a large hyaluronatebinding fibroblast proteoglycan, was studies in rat prenatal and postnatal development. In adult rat white matter and cerebellum, the distribution of versican was identical to that previously reported for brain‐specific glial hyaluronate‐binding protein (GHAP). Versican was also found in gray matter where it formed characteristic coats around large neurons. It was also found in peripheral tissues, namely, kidney medulla, myotendinous junctions, and endoneurial and endomysial sheaths. In rat embryo the most notable finding was the presence of large amounts of versican immunoreactive material in precartilaginous mesenchyma. In embryonal CNS, versican was mainly confined to the marginal zone on the surface of the cerebral hemispheres. Versican expression mainly occurred postnatally in brain and spinal cord. In spinal cord white matter, versican immunoreactivity was already present in 3‐day‐old rats and preceded the appearance of GHAP, which was first detected on day 13 after the onset of myelination. Versican expression was markedly delayed in gray matter. The characteristic perineuronal coats were first observed on day 21 in the cerebral cortex. It is concluded that, with the exception of hyaluronate, brain extracellular matrix (ECM) is mainly produced postnatally and that the ECM protein produced by brain cells, most likely astrocytes, is similar to that produced by precartilaginous mesenchyma. © 1993 Wiley‐Liss, Inc.
Transient reversion of O4+ Galc− oligodendrocyte progenitor development in response to the phorbol ester TPA
Authors: Avossa D. , Pfeiffer S. E. 
Published: May 2005

AbstractThe physiological importance of protein kinase C during oligodendrocyte progenitor maturation was investigated by analyzing the effects of the protein kinase C activator phorbol 12‐myristate 13‐acetate (TPA) on the morphology, proliferation, and differentiation of oligodendrocytes at sequential stages of development. Monoclonal antibodies A2B5 and O4 were used to identify the A2B5+ O4− and the A2B5+ O4+ galactocerebroside− progenitor stages. Anti‐galactocerebroside and anti‐myelin basic protein were used to identify mature, post‐mitotic oligodendrocytes. Proliferation was measured by bromodeoxyuridine incorporation. Within 24 hr after addition, TPA induced a down‐regulation of the O4 antigen in OL progenitors, and an increase of expression of the intermediate filament protein vimentin, leading to a phenotypic reversion from the vimentin− A2B5+ O4+ phenotype to the less mature vimentin+ A2B5+ O4− stage. Concomitantly, TPA induced an increase in the number of bromodeoxyuridine‐labeled oligodendrocyte progenitors and extensive process elongation. The response of O4+ progenitors was transient. Even with continued exposure to TPA, by 4 days after TPA addition the reverted cells ceased proliferation, reacquired O4 immunoreactivity, became vimentin‐negative, and began to express galactocerebroside and myelin basic protein, and to display the complex, highly branched morphology characteristic of terminally differentiated oligodendrocytes. These results indicate that modulation of protein kinase C activity by TPA induces a transient reversion of O4+ progenitors to less mature O4− cells, causing a transient inhibition of terminal differentiation. The relationship of these data to similar responses of the OL lineage to specific growth factors and implications for remyelination after pathologic injury are discussed. © 1993 Wiley‐Liss, Inc.
Expression of the class III β‐tubulin gene during axonal regeneration of rat dorsal root ganglion neurons
Authors: Moskowitz P. F. , Smith R. , Pickett J. , Frankfurter A. , Oblinger Monica M. 
Published: May 2005

AbstractThe effect of peripheral axotomy on the expression of the class III β‐tubulin gene in adult dorsal root ganglion (DRG) neurons was examined. Of the 5 isotypic classes of β‐tubulin expressed in the mammalian nervous system, only the class III β‐tubulin is neuron specific. While information about the expression of several of the tubulin genes during neuronal development and regeneration has become available recently, very little is known about the expression of βIII‐tubulin during axonal regeneration. To explore this issue, we examined axotomy‐induced changes in βIII‐tubulin mRNA levels in adult rat lumbar dorsal root ganglion (DRG) neurons at different times (1–28 days) after unilateral sciatic nerve crush using northern blotting of total RNA and quantitative in situ hybridization. These studies showed an initial decrease in βIII‐tubulin mRNA levels in axotomized DRG neurons as compared to contralateral controls at 1 day after injury followed by robust increases in βIII‐tubulin mRNA levels relative to contralateral controls from 1 to 4 weeks after injury. We postulate that βIII‐tubulin may play an essential role in axonal growth because of its unique neuron‐specific pattern of expression and its substantial increase in neurons that have been stimulated to regrow their axons. © 1993 Wiley‐Liss, Inc.
Use of nano‐liquid chromatography for the analysis of glycyrrhizin and glycyrrhetic acid in licorice roots and candies
Authors: Fanali Salvatore , Aturki Zeineb , D'Orazio Giovanni , Raggi Maria Augusta , Quaglia Maria Giovanna , Sabbioni Cesare , Rocco Anna 
Published: May 2005

AbstractGlycyrrhizin (G) and glycyrrhetic acid (GA) were separated by using nano‐liquid chromatography (nano‐LC) in a fused silica capillary packed with RP18 stationary phase (75 μm ID, effective length 33 cm, packed 23 cm) eluting at 300 nL/min in a gradient mode. The mobile phase was a mixture of water‐MeOH‐MeCN‐acetic acid (29 : 35 : 35 : 1, v/v/v/v) that was delivered for one minute and after this was modified by reducing the water content (14 : 42.5 : 42.5 : 1, v/v/v/v). The intra‐day and inter‐day relative standard deviations (of retention time and peak area) were satisfactory (lower than 2.9 and 4%, respectively). The linearity of the nano‐LC method was assessed in the range 0.62–5.00 μg/mL and 80–200 μg/mL for GA and G, with R 2 = 0.996 and 0.995, respectively. The licorice was extracted with a mixture of ethanol‐water, diluted with the mobile phase, and injected for the analysis.
Comparison of microemulsion electrokinetic chromatography and micellar electrokinetic chromatography methods for the analysis of phenolic compounds
Authors: Huang Hsi‐Ya , Lien Wei‐Chih , Chiu Chen‐Wen 
Published: May 2005

AbstractIn this study, microemulsion electrokinetic chromatography (MEEKC) and micellar electrokinetic chromatography (MEKC) were compared for their abilities to separate and detect thirteen phenolic compounds (syringic acid, p‐coumaric acid, vanillic acid, caffeic acid, gallic acid, 3,4‐dihydroxybenzoic acid, 4‐hydroxybenzoic acid, (+)‐catechin, (–)‐epigallocatechin, (–)‐epicatechin gallate, (–)‐epigallocatechin gallate, (–)‐epicatechin, and (–)‐gallocatechin), and two other ingredients (caffeine and theophylline) in teas and grapes. Separation of phenolic compounds was improved by changing the SDS concentration for MEEKC, but the SDS concentration rarely affected the resolution for MEKC. Organic modifier (acetonitrile or methanol) was found to markedly influence the resolution and selectivity for both MEEKC and MEKC systems. In addition, a higher voltage and a higher column temperature improved the separation efficiency without any noticeable reduction in resolution for MEEKC whereas they caused a poor resolution for the MEKC system. Although separations with baseline resolution were achieved by the optimized MEEKC and MEKC methods, the separation selectivity resulting from the proposed MEEKC method was completely different from that of MEKC.