bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changing sensitivity to cell death during development of retinal photoreceptors
Authors: Chiarini Luciana B. , Leal‐Ferreira Mona Lisa , de Freitas Fabíola G. , Linden Rafael 
Published: December 2003

AbstractPhotoreceptor cell death occurs during both normal and pathological retinal development. We tested for selective induction and blockade of cell death in either retinal photoreceptors or their precursors. Organotypical retinal explants from rats at postnatal days 3–11 were treated in vitro for 24 hr with thapsigargin, okadaic acid, etoposide, anisomycin, or forskolin. Explant sections were examined for cell death, and identification of either photoreceptors or proliferating/immediate postmitotic cells followed imunohistochemistry for either rhodopsin or bromodeoxyuridine and proliferating cell nuclear antigen, respectively. Photoreceptor cell death was selectively induced by either thapsigargin or okadaic acid, whereas death of proliferating/immediate postmitotic cells was induced by etoposide. Prelabeling of proliferating precursors allowed direct demonstration of changing sensitivity of photoreceptors to various chemicals. Degeneration of both photoreceptors and proliferating/immediate postmitotic cells depended on protein synthesis. Increase of intracellular cyclic AMP blocked degeneration of postmitotic, but not of proliferating, photoreceptor precursors. The selective induction and blockade of cell death show that developing photoreceptors undergo progressive changes in mechanisms of programmed cell death associated with phenotypic differentiation. © 2003 Wiley‐Liss, Inc.
Dual role of cyclic AMP‐dependent protein kinase in neuritogenesis and synaptogenesis during neuronal differentiation
Authors: Tojima Takuro , Kobayashi Suguru , Ito Etsuro 
Published: December 2003

AbstractTo create precise neural circuits in the nervous system, neuritogenesis and synaptogenesis are the critical cellular processes during neuronal differentiation. We examined the cyclic AMP (cAMP)‐responsible signaling pathways for regulating neuritogenesis and synaptogenesis in NG108‐15 cells. A rise in intracellular cAMP concentration by a membrane‐permeable cAMP analog, dibutyryl cAMP (DBcAMP), led to an increase in the number of neurites and varicosities. Inhibition of cAMP‐dependent protein kinase (PKA) activity by a PKA inhibitor (H89) accelerated this neuritogenesis and neurite outgrowth rate. Treatment with H89, however, decreased the number of varicosities and the frequency of postsynaptic miniature current recorded in the cultured cells, resulting in suppression of synaptogenesis. Immunoblot analyses revealed that PKA activity mediates phosphorylation of a gene transcription factor, cAMP‐response element binding protein (CREB). On the other hand, inhibition of a mitogen‐activated protein kinase (MAPK)/extracellular signal‐regulated kinase (ERK) pathway by a MAPK/ERK kinase (MEK) inhibitor (PD98059) suppressed both neuritogenesis and neurite outgrowth without CREB phosphorylation. These results suggest strongly that PKA simultaneously plays two different roles in neuronal differentiation: inhibition of neuritogenesis and stimulation of synaptogenesis, via CREB‐mediated gene expression. © 2003 Wiley‐Liss, Inc.
Proteasome inhibition arrests neurite outgrowth and causes “dying‐back” degeneration in primary culture
Authors: Laser Heike , Mack Till G.A. , Wagner Diana , Coleman Michael P. 
Published: December 2003

AbstractProteasome inhibitors such as lactacystin were first isolated when assaying their ability to stimulate neurite outgrowth in neuronal‐like cell lines; however, their effect on neurites in primary culture has been largely neglected. We report here that lactacystin causes immediate arrest of nerve growth factor (NGF)‐stimulated neurite outgrowth in sympathetic and sensory explant cultures. This is followed by neurite degeneration that in sympathetic cultures has a distinctive “dying‐back” morphology. Remarkably, this occurs even at concentrations below that required to induce neurite outgrowth in PC12 cells. Thus, lactacystin opposes rather than potentiates the effect of NGF on sympathetic neurite outgrowth and the role of the ubiquitin proteasome pathway in growth and long‐term maintenance of axons and dendrites differs from that in neuritogenesis in neuronal‐like cell lines. Retrograde degeneration caused by blocking of the ubiquitin proteasome pathway may mimic some aspects of gracile axonal dystrophy, a dying‐back axonopathy in mice caused by ubiquitin hydrolase (Uch‐l1) deficiency, and may be relevant to human neurodegenerative diseases involving ubiquitination or proteasome abnormalities. © 2003 Wiley‐Liss, Inc.
Elevation of mitochondrial glutathione by γ‐glutamylcysteine ethyl ester protects mitochondria against peroxynitrite‐induced oxidative stress
Authors: Drake Jennifer , Sultana Rukhsana , Aksenova Marina , Calabrese Vittorio , Butterfield D. Allan 
Published: December 2003

AbstractMitochondria under oxidative stress are thought to play a key role in various neurodegenerative disorders by directing neurons to cell death. Protection by antioxidants against oxidative stress to mitochondria may prove to be beneficial in delaying onset or progression of these diseases. We have investigated the ability of γ‐glutamylcysteine ethyl ester (GCEE) to upregulate mitochondrial glutathione (GSH) in vivo or in vitro and protect against subsequent in vitro peroxynitrite (ONOO−) damage. Mitochondria pretreated in vitro with GCEE were protected against oxidative damage induced by peroxynitrite, as assessed by mitochondrial swelling, changes in mitochondrial membrane potential, 3‐nitrotyrosine formation, protein carbonyl formation, and cytochrome c release. Loss of mitochondrial function in neuronal cell cultures by the oxidants 2,2,′Azobis(2‐amidino‐propane)dihydrochloride (AAPH) and ONOO− was ameliorated by treatment with GCEE. In vivo studies showed that mitochondria isolated from animals injected intraperitoneally with GCEE were protected partially against oxidative modifications induced by ONOO−. Taken together, these results suggest that GCEE may be effective in increasing mitochondrial GSH and may be prove to have therapeutic relevance in neurodegenerative disorders associated with oxidative stress and mitochondrial dysfunction. © 2003 Wiley‐Liss, Inc.
Iridoids from Scrophularia buergeriana attenuate glutamate‐induced neurotoxicity in rat cortical cultures
Authors: Kim So Ra , Koo Kyung Ah , Sung Sang Hyun , Ma Choong Je , Yoon Jeong Seon , Kim Young Choong 
Published: December 2003

AbstractIn previous work, we isolated 7 neuroprotective iridoid glycosides from the 90% MeOH fraction of Scrophularia buergeriana (Scrophulariaceae). We therefore investigated the mode of action of 8‐O‐E‐p‐methoxycinnamoyl‐harpagide (8‐MCA‐Harp), the most potent neuroprotective iridoid, and its aglycone, harpagide (Harp) using primary cultures of rat cortical cells in vitro. 8‐MCA‐Harp only revealed its neuroprotective activity in a pretreatment paradigm; this iridoid had more selectivity in protecting neurons against N‐methyl‐D‐aspartate (NMDA)‐induced neurotoxicity as opposed to that induced by kainic acid (KA). On the other hand, Harp exerted significant neuroprotective activity when it was administered either before or after glutamate insult and protected cultured neuronal cells from neurotoxicity induced by NMDA or KA. Furthermore, Harp significantly prevented the decrease of glutathione, an antioxidative compound in the brain, in our cultures. Finally, 8‐MCA‐Harp and Harp could successfully reduce the overproduction of nitric oxide and the level of cellular peroxide in cultured neurons. Collectively, these results suggested that Harp and 8‐MCA‐Harp protected primary cultured neurons against glutamate‐induced oxidative stress primarily by acting on the antioxidative defense system and on glutamatergic receptors, respectively. © 2003 Wiley‐Liss, Inc.
Microglial cell cycle‐associated proteins control microglial proliferation in vivo and in vitro and are regulated by GM‐CSF and density‐dependent inhibition
Authors: Koguchi Ken , Nakatsuji Yuji , Okuno Tatsusada , Sawada Makoto , Sakoda Saburo 
Published: December 2003

AbstractHyperplasia of microglia is one characteristic of reactive gliosis, which is observed in various pathologic conditions in the central nervous system (CNS). To investigate the regulation mechanisms of microglial proliferation, the effect of granulocyte macrophage colony‐stimulating factor (GM‐CSF) on the expression of cell cycle‐associated proteins was examined in the microglial cell line GMI‐M6‐3. After GM‐CSF administration, cyclins D1, E, and A and cyclin‐dependent kinase inhibitor p21Cip1 were increased, and another cyclin‐dependent kinase inhibitor, p27Kip1, was decreased with morphologic transformation into ameboid form. By contrast, downregulation of these cyclins and p21Cip1, and strong upregulation of p27Kip1 accompanied by ramification were observed with GM‐CSF deprivation. We also found that GMI‐M6‐3 exhibited homotypic contact inhibition of proliferation without any morphologic transformation. The increase of p27Kip1 and the decrease of cyclin A were suggested to play an important role in microglial contact inhibition. In addition, the direct effect of p27Kip1 to inhibit microglial proliferation was demonstrated both in vitro and in vivo by overexpression of p27Kip1. © 2003 Wiley‐Liss, Inc.
Atypical antipsychotics attenuate neurotoxicity of β‐amyloid(25–35) by modulating Bax and Bcl‐Xl/s expression and localization
Authors: Wei Zelan , Mousseau Darrell D. , Richardson J. Steven , Dyck Lillian E. , Li Xin‐Min 
Published: December 2003

AbstractWe have demonstrated recently that atypical antipsychotics possess neuroprotective actions in H2O2‐mediated and serum‐withdrawal models of cell death. In the present study, we compared the ability of atypical and typical antipsychotics to protect against an insult mediated by Aβ(25–35), an apoptogenic fragment of the Alzheimer's disease‐related β‐amyloid (Aβ) peptide. Treatment of PC12 cell cultures with Aβ(25–35) did not significantly alter total cellular expression levels of Bax, a proapoptotic Bcl‐2 family member, or levels of Bcl‐XL, an antiapoptotic analogue. Treatment with Aβ(25–35), however, did result in mitochondrial translocation of Bax, which effectively increased the mitochondrial ratio of Bax to Bcl‐XL. This relative increase in proapoptotic molecules was reduced by pretreatment with atypical (quetiapine and olanzapine) and typical (haloperidol) antipsychotics. We also observed a selective increase in proapoptotic Bcl‐XS immunodetection in haloperidol‐treated cells, which was evident particularly in the mitochondrial compartment. This increase in proapoptotic molecules may account for the lower neuroprotective potential of haloperidol, as determined by the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium (MTT) reduction assay. The disparate neuroprotective effects of atypical and typical antipsychotics/neuroleptics may be due to their respective abilities to regulate pro‐ and anti‐apoptotic protein translocation and expression. © 2003 Wiley‐Liss, Inc.
Isolation and characterization of neural progenitor cells from post‐mortem human cortex
Authors: Schwartz Philip H. , Bryant Peter J. , Fuja Tannin J. , Su Hailing , O'Dowd Diane K. , Klassen Henry 
Published: December 2003

AbstractPost‐mortem human brain tissue represents a vast potential source of neural progenitor cells for use in basic research as well as therapeutic applications. Here we describe five human neural progenitor cell cultures derived from cortical tissue harvested from premature infants. Time‐lapse videomicrography of the passaged cultures revealed them to be highly dynamic, with high motility and extensive, evanescent intercellular contacts. Karyotyping revealed normal chromosomal complements. Prior to differentiation, most of the cells were nestin, Sox2, vimentin, and/or GFAP positive, and a subpopulation was doublecortin positive. Multilineage potential of these cells was demonstrated after differentiation, with some subpopulations of cells expressing the neuronal markers β‐tubulin, MAP2ab, NeuN, FMRP, and Tau and others expressing the oligodendroglial marker O1. Still other cells expressed the classic glial marker glial fibrillary acidic protein (GFAP). RT‐PCR confirmed nestin, SOX2, GFAP, and doublecortin expression and also showed epidermal growth factor receptor and nucleostemin expression during the expansion phase. Flow cytometry showed high levels of the neural stem cell markers CD133, CD44, CD81, CD184, CD90, and CD29. CD133 markedly decreased in high‐passage, lineage‐restricted cultures. Electrophysiological analysis after differentiation demonstrated that the majority of cells with neuronal morphology expressed voltage‐gated sodium and potassium currents. These data suggest that post‐mortem human brain tissue is an important source of neural progenitor cells that will be useful for analysis of neural differentiation and for transplantation studies. © 2003 Wiley‐Liss, Inc.
Functional properties and retrogradation behaviour of native and chemically modified starch of mucuna bean (Mucuna pruriens)
Authors: Adebowale Kayode O , Lawal Olayide S 
Published: December 2003

AbstractMucuna bean (Mucuna pruriens) starch was isolated and subjected to chemical modification by oxidation and acetylation. The proximate analysis of the non‐starch components of the native starch on a dry weight basis was 92 g kg−1 moisture, 5 g kg−1 ash, 2 g kg−1 fat, 7 g kg−1 crude fibre and 19 g kg−1 protein. Chemical modification reduced the values for all the non‐starch components except the moisture level. For all the samples, swelling power and solubility increased as the temperature increased in the range 50–90 °C. The swelling power of mucuna native starch (MNS) and mucuna acetylated starch (MAS) increased with increasing acidity and alkalinity, while that of mucuna oxidised starch (MOS) only increased with increasing pH in the acidic range. The maximal solubility of all the starches was observed at pH 12. All the starch samples absorbed more oil than water. The lowest gelation concentration followed the trend MAS < MNS < MOS. Chemical modification reduced the gelatinisation temperature (Tp), while peak viscosity (Pv), hot paste viscosity (Hv) and cold paste viscosity (Cv) decreased after oxidation but increased following acetylation. The setback tendency of the native starch was reduced significantly after chemical modification. However, the breakdown value of MNS, 65 BU (Brabender units), was lower than that of MOS (78 BU) but higher than that of MAS (40 BU). Differential scanning calorimetry studies of gelatinisation and retrogradation revealed that chemical modification reduced the onset temperature (To), peak temperature (Tp) and conclusion temperature (Tc). Oxidation and acetylation reduced the gelatinisation and retrogradation enthalpies of the native starch. The enthalpy of retrogradation of the starches increased as the length of storage increased. Copyright © 2003 Society of Chemical Industry
Kinetics of ultraviolet light inactivation of Escherichia coli O157:H7 in liquid foods
Authors: Ngadi Michael , Smith James P , Cayouette Bernard 
Published: December 2003

AbstractThe effects of pH, depth of food medium and ultraviolet (UV) light dose on the inactivation of Escherichia coli O157:H7 in UV‐opaque products such as apple juice (pH 3.5) and egg white (pH 9.1) were investigated. The applied UV dose ranged from 0 to 6.5 mW min cm−2, while the depths of the medium were 1, 3.5, 5 and 10 mm. The pH of the medium did not affect the inactivation of E coli O157:H7, since similar inactivation characteristics were obtained for both apple juice and liquid egg white. As expected, decreasing the depth of the medium increased the inactivation of E coli O157:H7. More than a 5‐log reduction was obtained when the fluid depth and UV dose were 1 mm and 6.5 mW min cm−2 respectively. However, less than a 1‐log reduction was obtained when the fluid depth was 10 mm. A two‐phase kinetic model was used to model the inactivation of E coli O157:H7. This model indicated that at higher fluid depths the inactivation rate was controlled by the second, slower inactivation phase, resulting in a lower overall inactivation. The visual appearance of the treated apple juice and egg white did not show any discolouration changes during 4 weeks of storage at ambient temperature (25 °C). Copyright © 2003 Society of Chemical Industry
Changes in physicochemical properties and microstructure of dried squid during softening treatment
Authors: Konishi Fumiko , Fukunaga Yoshiko , Yoneda Chie , Shimomura Michiko , Kasai Midori , Hatae Keiko 
Published: December 2003

AbstractDried squid were prepared at 4 or 40 °C and softened first in water and then in alkaline solution. The physicochemical and structural changes in the dried squid during the softening treatment were examined. A significantly higher wet weight was observed for the 4 °C‐dried squid during the softening treatment compared with the 40 °C‐dried squid. The rupture stress and rupture energy of the 40 °C‐dried squid were significantly higher than those of the 4 °C‐dried squid during the softening treatment. The sodium dodecyl sulphate polyacrylamide slab gel electrophoresis (SDS‐PAGE) pattern of the 4 °C‐dried squid was almost the same as that of raw squid. The SDS‐PAGE pattern of the 40 °C‐dried squid showed many fragments of lower molecular weight. After soaking in distilled water the SDS‐PAGE pattern of the 40 °C‐dried squid did not change significantly; however, the SDS‐PAGE pattern of the 4 °C‐dried squid became the same as that of the 40 °C‐dried squid. Histological analysis by light microscopy showed the formation of muscle fibre bundles in the 40 °C‐dried squid. A higher water permeation was observed among the muscle fibres of the alkali‐softened 4 °C‐dried squid when compared with the alkali‐softened 40 °C‐dried squid. Copyright © 2003 Society of Chemical Industry
Immunodetection of legume proteins resistant to small intestinal digestion in weaned piglets
Authors: Salgado Paulo , Freire João PB , Ferreira Ricardo B , Teixeira Artur , Bento Ofélia , Abreu Manuel C , Toullec René , Lallès Jean‐Paul 
Published: December 2003

AbstractExperiments were conducted to investigate the biochemistry of digestion of the major storage proteins from soya bean, pea, faba bean, blue lupin, and chickpea seeds in the ileum of piglets. Hyperimmune plasmas against the crude protein extracts and the purified 11S and 7S globulin fractions of each legume seed and an anti‐pea albumin PA2 and lectin antibody were used. They served to probe immunoblots of feed protein extracts and ileal digesta samples. Globally, the recognition by plasmas of intact or partially digested proteins in ileal digesta was rather faint, in agreement with the fairly high in vivo digestibility data obtained with these legume seed proteins. Nevertheless, immunoreactive polypeptides found in digesta of piglets fed pea, faba bean and chickpea belonged mainly to proteins of the 7S family, and to other proteins including low‐molecular weight components such as PA2 albumin and lectin in the case of pea. In piglets fed lupin, nearly intact polypeptides from the 11S family were detected. To conclude, the present immunochemical study conducted on ileal digesta of piglets revealed a few dietary legume proteins of the vicilin and albumin families. Legumin proteins were demonstrated unequivocally in the case of lupin and white chickpea. Copyright © 2003 Society of Chemical Industry
Trypsin inhibitor activity of soybean as affected by genotype and fertilisation
Authors: Vollmann Johann , Grausgruber Heinrich , Wagentristl Helmut , Wohleser Heinrich , Michele Pavel 
Published: December 2003

AbstractThe presence of protease inhibitors in soybean prohibits the utilisation of the raw beans for food and feed. However, little information is available about environmental influences and the effects of nitrogen and sulphur supply on the antinutritional constituents of soybean. As these factors may influence protease inhibitors, soybean genotypes segregated according to the presence or absence of the Kunitz trypsin inhibitor have been evaluated for trypsin inhibitor activity (TIA) in field trials. TIA was affected significantly by environment (geographical location), fertilisation treatment and genotype. Environmental means of TIA were between 69.5 and 104.8 mg g−1. Nitrogen application, which caused an increase in seed protein content, resulted in a reduction in TIA by about 15% as compared with the control. Remarkably, simultaneous application of nitrogen and sulphur in the form of ammonium sulphate had a similar reductive effect on TIA to that of nitrogen application alone, although soybean protease inhibitors are rich in sulphur amino acids. Significant genetic variation in TIA was found both within the genotype class with the Kunitz inhibitor present as well as within the class lacking this inhibitor. The results suggest that TIA of soybean may be modified considerably by genetic improvement and appropriate agronomic management. Copyright © 2003 Society of Chemical Industry
Compositional changes in seeds influenced by their positions in different whorls of mature sunflower head
Authors: Munshi SK , Kaushal Babita , Bajaj RK 
Published: December 2003

AbstractThe physicochemical characteristics of seeds located in different whorls of the sunflower (Helianthus annuus L) head at maturity have been studied. The proportion of filled seeds decreased from the peripheral to the central whorl, with a 10‐fold decrease in filled/unfilled seed ratio. The dry weight of seeds and kernels and the oil content of kernels decreased from the peripheral towards the middle and central whorls. However, the dry weight of seeds and kernels in the seed crop was significantly higher and the oil content lower than in the oil crop. The contents of starch, total soluble sugars and reducing sugars were lower in the oil crop than in the seed crop. The starch content of peripheral whorls in the seed crop was much lower than that of central whorls, with accumulation of total soluble sugars and reducing sugars, whereas much less variability was observed with respect to the position of seeds on the sunflower head in the oil crop. The mean proportion of membrane lipids was higher and that of triacylglycerols lower in the seed crop than in the oil crop. The proportions of 16:0 and 18:1 were higher in the seed crop, while that of 18:2 was higher in the oil crop. Copyright © 2003 Society of Chemical Industry