bluuebunny/crossref_metadata_2025_split huggingface dataset:
The development of amphids and amphidial glands in adult Syngamus trachea (Nematoda: Syngamidae)
Authors: Jones Gwyneth M. 
Published: May 2005

AbstractNematode amphids are a pair of lateral cephalic sense organs, each comprising a group of sensory endings terminating in a cuticle‐lined pit. In Syngamus trachea, a parasite of birds, each amphid is surrounded by two non‐nervous supporting elements, a large gland cell basally and a smaller supporting cell anteriorly. The amphidial glands display high levels of secretory activity from five to six days postinfection. Secretory material is discharged through the lumen of the sense organ onto host tissue. The ultrastructure of amphids and amphidial glands has been investigated in newly moulted, immature and mature adults to trace the development of glandular activity and its effect on amphid‐amphidial gland relationships. In newly moulted adults, the glands have very low levels of secretory activity and appear to act only as supporting cells to the amphids. As secretory activity increases, the gland cell membrane surrounding the sensory endings is elaborated into a reticulum which probably forms the secretory surface. In mature adults the amphid pit is swollen and filled with secretion; the sensory endings are relegated to the periphery of the lumen. It is suggested that amphidial glands develop from typical supporting cells, but acquire a new role possibly associated with parasite attachment.
Origin and fate of germ cells in male and female embryos of Haplothrips verbasci (Osborn) (Insecta, Thysanoptera, Phlaeothripidae)
Authors: Heming B. S. 
Published: May 2005

AbstractComparison of germ cells in male and female embryos of the arrhenotokous thrips, Haplothrips verbasci, yields the following observations: A mean of 11 cleavage energids enter the posterior pole plasm of the egg after the sixth cleavage division and apparently become pole cells when they take up polar granules in their cytoplasm. The cells proliferate asynchronously prior to and during anatrepsis to yield a mean of 36 germ cells in male embryos and 31 in females. Visible sexual differentiation of germ cells begins during germ band elongation and is completed shortly after the appearance of appendages. Female germ cells are larger than those of the males and may contain two nucleoli. The germ cells separate into two groups just before katatrepsis and mesodermal cells collect about these to form the primary epithelial sheaths of the gonads and the primordia of the gonoducts shortly after revolution is completed. Each gonad contains a mean of 13 germ cells in male embryos and 7 in females – a number that persists until mitosis resumes after hatching. During ketatrepsis, a mean of 11 germ cells in male embryos and 2.6 in females fail to be enclosed within the gonads, become dispersed in the yolk and perhaps transform into vitellophages.Germ cell development in H. verbasci embryos resembles similar events taking place in psocid embryos, providing additional evidence for a close phylogenetic relationship between Thysanoptera and Psocoptera.
Differential myelinogenic capacity of specific developmental stages of the oligodendrocyte lineage upon transplantation into hypomyelinating hosts
Authors: Warrington A. E. , Barbarese E. , Pfeiffer S. E. 
Published: May 2005

AbstractThe capacity of oligodendrocytes (OLs) and their progenitors to migrate, proliferate, and differentiate in vivo was evaluated by transplanting highly enriched populations of sequential stage of the OL lineage (A2B5+ O4−, O4+ GalC−, and GalC+) into the telencephalon of the hypomyelinating mouse, shiverer. The shiverer mouse neither expresses the major myelin basic protein (MBP) nor makes normal myelin due to a large deletion in the gene for MBP. Thirty days after transplantation, serial 225 μm sections of the host brain were immunostained with antiserum to MBP and analyzed by confocal microscopy. The presence of MBP+ patches of myelin in the otherwise MBP− host brain allowed a retrospective analysis of the myelinogenic activity of the transplanted progenitors cells. Both the extent of MBP+ myelin and the location of MBP+ structures relative to the initial site of cell deposition were highly dependent on the developmental stage of the transplanted cells. Specifically, A2B5+ O4− OL progenitors migrated distances of ≥ 600 μm and produced MBP+ patches in nearly every slice of the host brain. An average of over 250 separate patches were found per host brain, some of which had cross‐sectional areas of > 250,000 μm2 containing as many as 60 MBP+ OL cell bodies, and with densities of myelination rivaling that of normal brain. In marked contrast, transplantation of O4+ GalC− cells produced only small (1,000–25,000 μm2), scattered (25–40 per brain) patches of MBP+ myelin containing one to five cell bodies, all of which were within 50 μm of the needle track or the nearest ventricular surface. GalC+ cells produced MBP+ myelin at a level similar to that of O4+ CalC− cells. These data suggest that the developmental transition of OL progenitors from the O4− to the O4+ pheno‐type is accompanied by a dramatic reduction in the innate capacity of the cells to migrate and survive in vivo. The use of developmentally identified, enriched populations of OL progenitor cells offers the opportunity for more precise analyses of transplantation and remyelination behavior, and relates to clinically relevant studies indicating that contaminant cell types can seriously interfere with the stable integration of donor tissue into the host. © 1993 Wiley‐Liss, Inc.
Induction of myelin genes during peripheral nerve remyelination requires a continuous signal from the ingrowing axon
Authors: Gupta S. K. , Pringle J. , Poduslo J. F. , Mezei Catherine 
Published: May 2005

AbstractThe effect of a permanent transection on myelin gene expression in a regenerating sciatic nerve and in an adult sciatic nerve was compared to establish the degree of axonal control exerted upon Schwann cells in each population. First, the adult sciatic nerve was crushed, and the distal segment allowed to regenerate. At 12 days post‐crush, the sciatic nerve was transected distal to the site of crush to disrupt the Schwann cell‐axonal contacts that had reformed. Messenger RNA (mRNA) levels coding for five myelin proteins were assayed in the distal segment of the crush‐transected nerve after 9 days and were compared to corresponding levels in the distal segments of sciatic nerves at 21 days post‐crush and 21 days post‐transection using Northern blot and slot‐blot analysis. Levels of mRNAs found in the distal segment of the transected and crush‐transected nerve suggested that Schwann cells in the regenerating nerve and in the mature adult nerve are equally responsive to axonal influences. The crush‐transected model allowed the genes that were studied to be classified according to their response to Schwann cell‐axonal contact. The levels of mRNAs were (1) down‐regulated to basal levels (PO and MBP mRNAs), (2) down‐regulated to undetectable levels (myelin‐associated glycoprotein mRNAs), (3) upregulated (mRNAs encoding 2′3′‐cyclic nucleotide phosphodiesterase and β‐actin), or (4) not stringently controlled by the removal of Schwann cell‐axonal contact (proteolipid protein mRNAs). This novel experimental model has thus provided evidence that the expression of some of the important myelin genes during peripheral nerve regeneration is dependent on continuous signals from the ingrowing axons. © 1993 Wiley‐Liss, Inc.
Electrophysiologic and molecular properties of cultured enteric glia
Authors: Broussardy D. L. , Bannerman P. G. C. , Tang C.‐M. , Hardy M. , Pleasure D. 
Published: May 2005

AbstractEnteric glia, the support cells of myenteric ganglia, have been widely studied with respect to their morphology and immunohistochemical phenotype, but little is known about their functional properties. We developed a method for the amplification of enteric glia from newborn guinea pigs to further characterize these cells. Treatment with a combination of basic fibroblast growth factor and the adenylate cyclase activator, cholera toxin, permitted expansion of enteric glial cultures to confluence and serial passage for up to 8 months. The long‐term cultured cells retained expression of (1) S100 protein, (2) GD3 ganglioside recognized by the monoclonal antibody LB1, and (3) the gene encoding glutamine synthetase. The electrophysiologic properties of cultured enteric glia were studied under whole‐cell patch clamp conditions. Most cells expressed “delayed rectifier”‐type potassium currents, and some also demonstrated tetrodotoxin‐sensitive sodium currents. Other subsets of voltage‐dependent potassium currents, calcium currents, and glutamate‐gated currents were not demonstrable. © 1993 Wiley‐Liss, Inc.
Transforming growth factor β as a neuronoglial signal during peripheral nervous system response to injury
Authors: Rogister B. , Delrée P. , Leprince P. , Martin D. , Sadzot C. , Malgrange B. , Munaut C. , Rigo J. M. , Lefebvre P. P. , Octave J.‐N. , Schoenen J. , Moonen G. 
Published: May 2005

AbstractIn contrast to the central nervous system (CNS), the peripheral nervous system (PNS) displays an important regenerative ability which is dependent, at least in part, on Schwann cell properties. The mechanisms which stimulate Schwann cells to adapt their behavior after a lesion to generate adequate conditions for PNS regeneration remain unknown.In this work, we report that adult rat dorsal root ganglion (DRG) neurons are able, after a lesion performed in vivo or when they are dissociated and cultured in vitro, to synthesize transforming growth factor β (TGFβ), a pleiotropic growth factor implicated in wound healing processes and in carcinogenesis. This TGFβ is tentatively identified as the β‐1 isoform. Adult rat DRG neurons release a biologically active form of TGFβ which is able to elicit multiple Schwann cell responses including a stimulation to proliferate. Moreover, purified TGFβ‐1 produces a Schwann cell morphology alteration and decreases the secretion of tissue‐type plasminogen activator (tPA) and enhances the secretion of plasminogen activator inhibitor (PAI) by Schwann cells. This generates conditions which are thought to favor a successful neuritic regrowth. Furthermore, purified TGFβ‐1 stimulates type IV collagen mRNA expression in Schwann cells. This subtype of collagen is associated with the process of myelinization. Finally, TGFβ‐1 decreases nerve growth factor (NGF) mRNA expression by Schwann cells, an effect which could participate in the maintenance of a distoproximal NGF gradient during nerve regeneration.We propose that neuronal TGFβ plays an essential role as a neuronoglial signal that modulates the response of Schwann cells to injury and participates in the successful regeneration processes observed in the PNS. © 1993 Wiley‐Liss, Inc.
Congruity of acetylcholine receptor, acetylcholinesterase, and Dolichos biflorus lectin binding glycoprotein in postsynaptic‐like sarcolemmal specializations in noninnervated regenerating rat muscles
Authors: Črne‐Finderle N. , Sketelj J. 
Published: May 2005

AbstractNoninnervated regenerating muscles are able to form focal postsynaptic‐like sarcolemmal specializations either in places of the former motor endplates ( “junctional” specializations) or elsewhere along the muscle fibers (extrajunctional specializations). The triple labeling histochemical method was introduced to analyse the congruity of focalization in such specializations of 3 synaptic components: acetylcholinesterase (AChE), acetylcholine receptor (AChR), and a specific synaptic glycoprotein which binds Dolichos biflorus lectin (DBAR). Noninnervated regenerating soleus and extensor digitorum longus (EDL) muscles of the rat were examined and compared with denervated muscles of neonatal and adult rats.All junctional sarcolemmal specializations in noninnervated regenerating muscles accumulated AChE and AChR. Localization of the 2 components was identical within the limits of resolution of the method. DBAR could not be demonstrated in junctional specializations in 17‐day‐old regenerating muscles. It seems that an agrin‐like inducing substance in the former junctional basal lamina invariably triggers the accumulation of both AChE and AChR in the underlying sarcolemma of the regenerating muscle fiber. However, accumulation of DBAR would probably require the presence of the motor nerve.In most of the extrajunctional sarcolemmal specializations in 8‐day‐old regenerating soleus and EDL muscles, both AChE and AChR accumulated. However, about 10 percent of AChE accumulations lacked AChR and about 35% of AChR accumulations lacked AChE. Even greater variability was observed in 17‐day‐old regenerating muscles. The presence of DBAR in the extrajunctional postsynaptic‐like sarcolemmal specializations could not be demonstrated. Similar extrajunctional sarcolemmal specializations were observed in denervated postnatal rat muscles. About 70% contained both AChE and AChR, and 30% contained only AChR, but none contained DBAR. In denervated mature muscles, sparse extrajunctional AChR accumulations did not contain detectable amounts of AChE. The ability to form complex postsynaptic‐like sarcolemmal specializations in the absence of nerve, which is probably inherent to noninnervated immature muscle fibers, may be reduced with muscle maturation. Variable accumulation of individual components in the postsynaptic‐like specializations indicates that different triggering factors may be involved in their accumulation or, at least, the mechanisms of their accumulation can function relatively independently. © 1993 Wiley‐Liss, Inc.
Synaptophysin – a common constituent of presumptive secretory microvesicles in the mammalian pinealocyte: A study of rat and gerbil pineal glands
Authors: Redecker P. , Bargsten G. 
Published: May 2005

AbstractRecent studies have established that pinealocytes of the mammalian pineal gland contain marker molecules of neuroendocrine cells or paraneurons like the synaptic vesicle‐associated protein synaptophysin (p38). The objective of this study was to identify the subcellular synaptophysin‐positive compartment and to characterize in detail the intracellular distribution of this protein in rat and gerbil pinealocytes. An analysis of serial semithin sections of plastic‐embedded pineals immunostained for synaptophysin, including computer‐assisted optical density measurements of synaptophysin immunoreactivities, demonstrated unequivocally that synaptosphysin was highly concentrated in dilated process terminals of the pinealocytes. More than 75% of these process terminals were found to border or lie within the pericapillary space. At the ultrastructural level, they contained accumulations of small clear vesicles of variable size that turned out to be the site of synaptosphysin immunoreactivity when immunogold staining was performed. In addition, microvesicles surrounding synaptic ribbons were also immunolabeled. Hence, the pinealocyte is the first neuroendocrine cell type that has now been shown to concentrate synaptophysin‐positive microvesicles in perivascular process endings. This observation lends strong support to the hypothesis that small clear vesicles in neuroendocrine cells in general, and in pinealocytes in particular, serve secretory functions. The quantitative analysis of completely sectioned process endings revealed that the microvesicles outnumber by far the amount of dense core vesicles and therefore cannot arise by endocytosis of dense core vesicle membranes. Thus, small synaptic‐like vesicles probably constitute an independent secretory pathway of the paraneuronal pinealocytes.In the present study, we could also establish the absence of immunoreactivity for synapsin I (belonging to a family of neuron‐specific nerve terminal phosphorproteins) from pinealocytes. Synapsin I immunoreactivity was only detectable in intrapineal nerve terminals and varicosities. Taken together, the immunostaining patterns of the pineal gland obtained with antibodies directed against synaptic vesicle‐associated proteins render the mammalian pinealocyte a very special type of neuroendocrine cell or paraneuron rather than a “classic” neuron. © 1993 Wiley‐Liss, Inc.
Hydroxyl radical production and lipid peroxidation paralles selective post‐ischemic vulnerability in gerbil brain
Authors: Hall Edward D. , Andrus P. K. , Althaus J. S. , Von Voigtlander P. F. 
Published: May 2005

AbstractThe salicylate trapping method was used to investigate the changes in hydroxyl radical (·OH) levels in the selectively vulnerable hippocampus compared to the cerebral cortex of gerbils subjected to a 10 min period of near complete forebrain ischemia. Salicylate‐derived 2,5‐dihydroxybenzoic acid (2,5‐DHBA) was measured in sham‐operated animals and at 1, 5, and 15 min of reperfusion. A basal level of 2,5‐DHBA was also seen in non‐ischemic gerbil brain, both in the hippocampus and cortex. The hippocampal basal level was 160% higher than in the cortex (P < .01). Treatment with the cytochrome P450 inhibitor SKF‐525A (50 mg/kg s.c. 30 min before measurement) did not affect this basal level in either hippocampus or cortex, which argues against a contribution of metabolic salicylate hydroxylation as its source. In contrast, pretreatment with the arachidonic acid cyclo‐oxygenase inhibitor ibuprofen (20 mg/kg s.c.) decreased (−68.8%) the level of salicylate hydroxylation in the hippocampus, but not the cortex. In animals subjected to 10 min of forebrain ischemia, a selective increase in 2,5‐DHBA was observed in the hippocampus at 1 min of reprerfusion which subsided by 5 min. No increase in salicylate hydroxylation was apparent in the cortex within the same time frame. The increase in ·OH in the hippocampus at 1 min of reperfusion was accompanied by a significant decrease (−15%; P < .03) in the hippocampal levels of vitamin E. No loss of vitamin E was observed in the cortex at the same time. It is hypothesized that the selective ischemic vulnerability of the hippocampus is mechanistically related to a selective post‐ischemic burst in ·OH in that region. Moreover, this may be based upon an intrinsically higher level of oxidative stress in that region as a by‐product of greater arachidonic acid turnover. © 1993 Wiley‐Liss, Inc.
Temperature‐dependent Raman scattering studies of improper and antidistortive phase transitions in (NH4)2Cd2(SO4)3
Authors: Galzerani J. C. , Katiyar R. S. 
Published: May 2005

AbstractPolarized Raman spectra of single crystals of (NH4)2Cd2(SO4)3 were studied at temperatures from room temperature to 13 K. Several temperature‐dependent variations in the phonon frequencies were observed that are related to the structural phase transitions in the material. The existence of a ferroelectric‐paraelectric phase transition was established at 91.5 K. The observed spectra suggested the existence of a new phase transition at about 162 K. This new transition is believed to be of antidistortive type, which is triggered by the softening of a phonon from the Brillouin zone boundary.
Molecular dynamics of antimony trichloride in crystals of bimolecular menshutkin complexes with benzene, diphenyl and phenanthrene by Raman spectroscopy
Authors: Kondyurin A. V. , Mikov S. N. , Kozulin A. T. 
Published: May 2005

AbstractThe Raman spectra of bimolecular complexes crystals of antimony trichloride with benzene, diphenyl and phenanthrene were studied at 77 K. A group theoretical analysis and normal coordinates analysis of the antimony trichloride vibrations in complexes was made. The variation of force field with the gas‐crystal phase change parameters of intermolecular interaction was defined. The interpretation of the lattice mode region was accomplished.
Novel approach for the rapid determination of water‐soluble organic acids in wine by co‐electroosmotic flow capillary zone electrophoresis
Authors: Bianchi Federica , Careri Maria , Corradini Claudio 
Published: May 2005

AbstractAn innovative protocol for the fast analysis of some organic acids in red wine by co‐electroosmotic capillary zone electrophoresis and indirect UV detection using hexadimethrine bromide (HDB) as coating agent was proposed. The adsorption of HDB onto the capillary wall provided a stable electroosmotic flow and separation of small anions was carried out using background electrolytes containing no polymer additive. Low RSD% values (<3.6%) in terms of migration times and effective mobilities were obtained from the analysis of a mixture of nitrate and nitrite and of a mixture of organic acids. An experimental design approach was used to investigate the effects of temperature, separation voltage, and percentage of methanol added to the running buffer solution on the separation of the analytes. A faster method allowing the separation of the organic acids involved in the malolactic fermentation of wine was developed. Using a running electrolyte consisting of 35% (v/v) methanol in a solution of 22 mM benzoic acid at pH 6.10 adjusted with 1.0 M TRIS‐base buffer, the separation of tartaric, malic, succinic, acetic, and lactic acids was feasible in less than 210 s. Application of the method to the quantification of the above‐mentioned organic acids in Italian red wine samples is reported.
Separation and analysis of the major constituents of cloves by micellar electrokinetic chromatography
Authors: Mandrioli Roberto , Musenga Alessandro , Ferranti Anna , Lasaponara Stefano Savino , Fanali Salvatore , Raggi Maria Augusta 
Published: May 2005

AbstractA micellar electrokinetic chromatographic method was developed and applied for the first time to the separation and quantification of the main components of cloves, namely eugenol and β‐caryophyllene. The analytes were separated in less than ten minutes in an unmodified fused silica capillary (effective length: 40.0 cm) using a background electrolyte composed of 25 mM carbonate buffer (pH 10.0) and 60 mM sodium dodecylsulfate. Analyte concentrations were determined in clove oil and in methanolic clove extracts after simple sequential dilution with methanol and background electrolyte, and the resulting electropherograms showed no interference due to other components. Precision assays gave satisfactory results, with mean standard deviation of peak areas lower than 4.7% (lower than 1.5% for migration times). The eugenol content of a commercial clove oil was about 70% (RSD% = 3.2), while that of β‐caryophyllene was about 15% (RSD% = 4.2); in clove extracts, on the other hand, eugenol was approximately 15% (RSD% = 4.7) and β‐caryophyllene 4% (RSD% = 5.1). Accuracy was also good (mean recovery >98%)
Untersuchungen über die Korrosion einiger Metalle und Metalloxyde in Natriumhydroxydschmelzen
Authors: Rahmel A. , Krüuger H.‐J. 
Published: May 2005

AbstractZiel der Untersuchungen war, einen Beitrag zur Aufklärung der Reaktionsabläufe zu leisten, die in den besonders für die Entzunderung von hochlegierten Chrom‐ und Chrom‐Nickel‐Stählen benutztenDie Untersuchungen erfolgten an den Metallen Silber, Gold, Platin, Nickel und Eisen und an den Metalloxyden FeO, Fe3O4, Fe2O3 und Cr2O3 in NaOH‐Schmelzen bei Temperaturen um 500°C. Besondere Aufmerksamkeit wurde dem Einfluß der Gasatmosphäre auf die Korrosionsgeschwindigkeit gewidmet.Mit Ausnahme des Silbers ist die Korrosion aller untersuchten Metalle und Oxyde unter Sauerstoff erheblich größer als unter Stickstoff, wobei ein Zusatz von Wasserdampf besonders unter Sauerstoff die Korrosion stark inhibiert. Unter wasserdampfhaltigem Stickstoff ist der Angriff der reinen NaOH‐Schmelzen praktisch vernachlässigbar. Nur Silber korrodiert bei Gegenwart von Wasserdampf stärker als unter trockenen Gasen. Die Korrosionsprodukte wurden chemisch, metallographisch sowie durch Röntgen‐ und Elektronenbeugung untersucht.Die geringe Korrosion unter Stickstoff zeigt, daß die Reaktion zwischen Metallen bzw. Metalloxyden und der NaOH‐Schmelze nicht oder nur recht langsam abläuft. Die beschleunigende Wirkung des Sauerstoffs und die inhibierende des Wasserdampfes deuten darauf hin, daß der Natriumperoxydgehalt der Schmelze in den meisten Fällen entscheidend für die Korrosionsgeschwindigkeit ist.