bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glutathione depletion resulting in selective mitochondrial complex I inhibition in dopaminergic cells is via an NO‐mediated pathway not involving peroxynitrite: implications for Parkinson's disease
Authors: Hsu Michael , Srinivas Bharath , Kumar Jyothi , Subramanian Rajagopalan , Andersen Julie 
Published: February 2005

AbstractAn early biochemical change in the Parkinsonian substantia nigra (SN) is reduction in total glutathione (GSH + GSSG) levels in affected dopaminergic neurons prior to depletion in mitochondrial complex I activity, dopamine loss, and cell death. We have demonstrated using dopaminergic PC12 cell lines genetically engineered to inducibly down‐regulate glutathione synthesis that total glutathione depletion in these cells results in selective complex I inhibition via a reversible thiol oxidation event. Here, we demonstrate that inhibition of complex I may occur either by direct nitric oxide (NO) but not peroxinitrite‐mediated inhibition of complex I or through H2O2‐mediated inhibition of the tricarboxylic acid (TCA) cycle enzyme α‐ketoglutarate dehydrogenase (KGDH) which supplies NADH as substrate to the complex; activity of both enzymes are reduced in PD. While glutathione depletion causes a reduction in spare KGDH enzymatic capacity, it produces a complete collapse of complex I reserves and significant effects on mitochondrial function. Our data suggest that NO is likely the primary agent involved in preferential complex I inhibition following acute glutathione depletion in dopaminergic cells. This may have major implications in terms of understanding mechanisms of dopamine cell death associated with PD especially as they relate to complex I inhibition.
Retinal‐specific ATP‐binding cassette transporter (ABCR/ABCA4) is expressed at the choroid plexus in rat brain
Authors: Bhongsatiern Jiraganya , Ohtsuki Sumio , Tachikawa Masanori , Hori Satoko , Terasaki Tetsuya 
Published: February 2005

AbstractATP‐binding cassette (ABC) transporter A4 is a member of the ABC transporter subfamily A which has been reported to be exclusively expressed in the retina. In contrast, a previous report has suggested a possible relationship between ABCA4 and CNS function. The purpose of the present study was to investigate the localization of ABCA4 mRNA and protein in rat brain. In situ hybridization analysis revealed that ABCA4 mRNA was localized in the lateral ventricles. RT–PCR analysis detected ABCA4 mRNA in isolated rat choroid plexus and conditionally immortalized rat choroid plexus epithelial cells (TR‐CSFB). Furthermore, ABCA4 protein was also detected in the isolated rat choroid plexus at about 250 kDa by western blot analysis, and its apparent molecular size was reduced by N‐glycosidase F treatment. These results suggest that glycosylated ABCA4 protein is expressed in rat choroid plexus epithelial cells. ABCA4 may play a role in the function of the blood–cerebrospinal fluid barrier and affect CSF conditions.
Differential regulation of multiple populations of granules in rat adrenal chromaffin cells by culture duration and cyclic AMP
Authors: Tang Kim San , Tse Amy , Tse Frederick W. 
Published: February 2005

AbstractWe employed carbon fiber amperometry to measure the amount of catecholamine released from individual granules (i.e. the quantal size, Q) of rat chromaffin cells. The distribution of Q1/3 of amperometric events could be reasonably described by the summation of at least three Gaussians, suggesting that rat chromaffin cells contained at least three distinct populations of granules, with a small, medium or large modal Q. After 3 days of culture, the mean cellular Q reduced by ∼14%, which did not arise from a uniform percentage decrease in the Q of every granule. Instead, the rundown involved a > 11% decrease in the proportional release from large Q granules and a > 19% decrease in the modal Q‐value of small Q granules. In contrast, when cells were cultured with dibutyryl‐cAMP (dBcAMP) for 3 days, their mean cellular Q increased by ∼38% (relative to time‐matched controls). This increase in Q was not associated with any shift in the proportional release from the three populations of granules. Instead, cAMP increased the average amount of catecholamines released from all three populations of granules. Our data raise the possibility that distinct populations of granules in rat chromaffin cells can be regulated either differentially or uniformly.
A domain at the C‐terminus of PS1 is required for presenilinase and γ‐secretase activities
Authors: Brunkan A. L. , Martinez M. , Wang J. , Walker E. S. , Goate A. M. 
Published: February 2005

AbstractThe structural requirements for presenilin (PS) to produce active presenilinase and γ‐secretase enzymes are poorly understood. Here we investigate the role the cytoplasmic C‐terminal region of PS1 plays in PS1 activity. Deletion or addition of residues at the PS C‐terminus has been reported to inhibit presenilinase endoproteolysis of PS and alter γ‐secretase activity. In this study, we use a sensitive assay in PS1/2KO MEFs to define a domain at the extreme C‐terminus of PS1 that is essential for both presenilinase and γ‐secretase activities. Progressive deletion of the C‐terminus demonstrated that removal of nine residues produces a PS1 molecule (458ST) that lacks both presenilinase processing and γ‐secretase cleavage of Notch and APP substrates. In contrast, removal of four or five residues had no effect (462ST, 463ST), while intermediate truncations partially inhibited PS1 activity. The 458ST mutant was unable to replace endogenous wtPS1 in HEK293 cells. Although 458ST was able to form a γ‐secretase complex, this complex was not matured, illustrated by mutant PS1 instability, lack of endoproteolysis, and little production of mature Nicastrin. These data indicate that the C‐terminal end of PS1 is essential for Nicastrin trafficking and modification as well as the replacement of endogenous PS1 by PS1 transgenes.
A complementary peptide approach applied to the design of novel semaphorin/neuropilin antagonists
Authors: Williams Gareth , Eickholt Britta J. , Maison Patrick , Prinjha Rabinder , Walsh Frank S. , Doherty Patrick 
Published: February 2005

AbstractSemaphorin 3A can inhibit axonal growth and induce neuronal apoptosis following binding to neuropilin‐1, with the membrane proximal MAM (meprin, A5, mu) domain in neuropilin‐1 playing a key role in the formation of a higher order receptor complex. If functional motifs on semaphorin 3A and/or the MAM domain can be identified, then small‐constrained peptides might be developed as antagonists. We have scored peptide pairs for complementary hydropathy and antisense homology to identify a candidate functional motif in the Ig domain of semaphorin 3A, and in the MAM domain of neuropilin‐1. Synthetic peptides corresponding to these sequences fully inhibit growth cone collapse induced by semaphorin 3A. A number of smaller peptides derived from the parental sequence also inhibited the response, particularly after they were constrained by a disulfide bond. Finally, we have used an algorithm to design a peptide that is a near‐perfect hydropathic complement of the candidate functional site in the MAM domain; this also inhibits the semaphorin 3A response. Thus, an algorithm‐driven methodology has led to the identification of three independent semaphorin 3A antagonists. Semaphorin 3F stimulates growth cone collapse following binding to the closest relative to neuropilin‐1 in the genome, neuropilin‐2. Where tested, the peptides that antagonise semaphorin 3A failed to inhibit the semaphorin 3F response.
Differences in serotonergic neurotransmission between rats displaying high or low anxiety/depression‐like behaviour: effects of chronic paroxetine treatment
Authors: Keck Martin E. , Sartori Simone B. , Welt Tobias , Müller Marianne B. , Ohl Frauke , Holsboer Florian , Landgraf Rainer , Singewald Nicolas 
Published: February 2005

AbstractDisturbances in serotonergic neurotransmission have been suggested to be closely interlinked with hyperactivity of the hypothalamic‐pituitary‐adrenocortical (HPA) system, and are likely to be involved in the pathophysiology of anxiety disorders and major depression. We therefore investigated markers of serotonergic transmission and their modulation by chronic paroxetine in rats selectively bred for high (HAB) or low (LAB) anxiety‐related behaviour, both under basal conditions and in response to emotional stress. Hippocampal serotonin 1 A (5‐HT1A) receptor mRNA expression was reduced in HAB rats, whereas 5‐HT concentrations in hippocampal microdialysates did not differ between HAB and LAB rats under basal conditions. In the hippocampus, overall expression of serotonin transporter binding sites was increased in HAB compared with LAB rats. Exposure to emotional stress failed to increase intrahippocampal 5‐HT release in HAB rats whereas LAB rats displayed a physiological, albeit small rise. Chronic paroxetine treatment markedly increased the stress‐induced rise in hippocampal 5‐HT in HAB, but not LAB rats. This effect may be (at least in part) related to a greater down‐regulation of hippocampal serotonin transporter binding sites by paroxetine in HABs compared with LABs, while 5‐HT1A receptor expression remained unaffected in this brain area. The findings indicate reduced hippocampal serotonergic transmission in HAB rats as compared with LAB rats, which is evident both at the presynaptic (5‐HT release) and the postsynaptic (5‐HT1A receptor) level. Chronic paroxetine enhanced the presynaptic responsivity in HAB rats, but not LAB rats, pointing to a preferential efficacy of paroxetine in rats with enhanced anxiety/depression‐related behaviour.
Protective autoimmunity: interferon‐γ enables microglia to remove glutamate without evoking inflammatory mediators
Authors: Shaked I. , Tchoresh D. , Gersner R. , Meiri G. , Mordechai S. , Xiao X. , Hart R. P. , Schwartz M. 
Published: February 2005

AbstractGlutamate in excessive amounts is a major contributor to neuronal degeneration, and its removal is attributed mainly to astrocytes. Traumatic injury to the central nervous system (CNS) is often accompanied by disappearance of astrocytes from the lesion site and failure of the remaining cells to withstand the ensuing toxicity. Microglia that repopulate the lesion site are the usual suspects for causing redox imbalance and inflammation and thus further exacerbating the neurotoxicity. However, our group recently demonstrated that early post‐injury activation of microglia as antigen‐presenting cells correlates with an ability to withstand injurious conditions. Moreover, we found that T cells reactive to CNS‐specific self‐antigens protected neurons against glutamate toxicity. Here, we show that antigen‐specific autoimmune T cells, by tailoring the microglial phenotype, can increase the ability of microglia‐enriched cultures to remove glutamate. This T‐cell‐mediated effect could not be achieved by the potent microglia‐activating agent lipopolysaccharide (LPS), but was dose‐dependently reproduced by the Th1 cytokine interferon (IFN)‐γ and significantly reduced by neutralizing anti‐IFN‐γ antibodies. Under the same conditions, IFN‐γ had no effect on cultured astrocytes. Up‐regulation of glutamate uptake induced by IFN‐γ activation was not accompanied by the acute inflammatory response seen in LPS‐activated cultures. These findings suggest that T cells or their cytokines can cause microglia to adopt a phenotype that facilitates rather than impairs glutamate clearance, possibly contributing to restoration of homeostasis.
Extracellular release of newly synthesized sphingosine‐1‐phosphate by cerebellar granule cells and astrocytes
Authors: Anelli Viviana , Bassi Rosaria , Tettamanti Guido , Viani Paola , Riboni Laura 
Published: February 2005

AbstractSphingosine‐1‐phosphate (S1P) is a potent biomediator that can act as either an intracellular or an intercellular messenger. In the nervous system it exerts a wide range of actions, and specific membrane receptors for it have been identified in various regions. However, the physiological origin of extracellular S1P in the nervous system is largely unknown. We investigated cerebellar granule cells at different stages of differentiation and astrocytes in primary cultures as possible origins of extracellular S1P. Although these cells show marked differences in S1P metabolism, we found that they can all release S1P and express mRNAs for S1P specific receptors. Extracellular S1P derives from the export of newly synthesized intracellular S1P, and not from the action of a released sphingosine kinase. S1P release is rapid, efficient, and can be regulated by exogenous stimuli. Phorbol ester treatment resulted in an increase in sphingosine kinase 1 activity in the membranes, accompanied by a significant increase in extracellular S1P. S1P release in cells from the cerebellum emerges as a regulated mechanism, possibly related to a specific pool of newly synthesized S1P. To our knowledge, this is the first evidence of the extracellular release of S1P by primary cells from the CNS, which supports a role of S1P as autocrine/paracrine physiological messenger in the cerebellum.
Role of the autophagic‐lysosomal system on low potassium‐induced apoptosis in cultured cerebellar granule cells
Authors: Canu Nadia , Tufi Roberta , Serafino Anna Lucia , Amadoro Giuseppina , Ciotti Maria Teresa , Calissano Pietro 
Published: February 2005

AbstractApoptotic and autophagic cell death have been implicated, on the basis of morphological and biochemical criteria, in neuronal loss occurring in neurodegenerative diseases and it has been shown that they may overlap. We have studied the relationship between apoptosis and autophagic cell death in cerebellar granule cells (CGCs) undergoing apoptosis following serum and potassium deprivation. We found that apoptosis is accompanied by an early and marked proliferation of autophagosomal–lysosomal compartments as detected by electron microscopy and immunofluorescence analysis. Autophagy is blocked by hrIGF‐1 and forskolin, two well‐known inhibitors of CGC apoptosis, as well as by adenovirus‐mediated overexpression of Bcl‐2. 3‐Methyladenine (3‐MA) an inhibitor of autophagy, not only arrests this event but it also blocks apoptosis. The neuroprotective effect of 3‐MA is accompanied by block of cytochrome c (cyt c) release in the cytosol and by inhibition of caspase‐3 activation which, in turn, appears to be mediated by cathepsin B, as CA074‐Me, a selective inhibitor of this enzyme, fully blocks the processing of pro‐caspase‐3. Immunofluorescence analysis demonstratesd that cathepsin B, normally confined inside the lysosomal‐endosomal compartment, is released during apoptosis into the cytosol where this enzyme may act as an execution protease. Collectively, these observations indicate that autophagy precedes and is causally connected with the subsequent onset of programmed death.
Potentiation of ATP‐induced currents due to the activation of P2X receptors by ubiquitin carboxy‐terminal hydrolase L1
Authors: Manago Yoshimasa , Kanahori Yoshiko , Shimada Aki , Sato Ayumi , Amano Taiju , Sato‐Sano Yae , Setsuie Rieko , Sakurai Mikako , Aoki Shunsuke , Wang Yu‐Lai , Osaka Hitoshi , Wada Keiji , Noda Mami 
Published: February 2005

AbstractMammalian neuronal cells abundantly express a de‐ubiquitinating isozyme, ubiquitin carboxy‐terminal hydrolase L1 (UCH L1). Loss of UCH L1 function causes dying‐back type of axonal degeneration. However, the function of UCH L1 in neuronal cells remains elusive. Here we show that overexpression of UCH L1 potentiated ATP‐induced currents due to the activation of P2X receptors that are widely distributed in the brain and involved in various biological activities including neurosecretion. ATP‐induced inward currents were measured in mock‐, wild‐type or mutant (C90S)‐UCH L1‐transfected PC12 cells under the conventional whole‐cell patch clamp configuration. The amplitude of ATP‐induced currents was significantly greater in both wild‐type and C90S UCH L1‐transfected cells, suggesting that hydrolase activity was not involved but increased level of mono‐ubiquitin might play an important role. The increased currents were dependent on cAMP‐dependent protein kinase (PKA) and Ca2+ and calmodulin‐dependent protein kinase (CaMKII) but not protein kinase C. In addition, ATP‐induced currents were likely to be modified via dopamine and cyclic AMP‐regulated phosphoprotein (DARPP‐32) that is regulated by PKA and phosphatases. Our finding shows the first evidence that there is a relationship between UCH L1 and neurotransmitter receptor, suggesting that UCH L1 may play an important role in synaptic activity.
In vitroandin vivoanalyses of human embryonic stem cell‐derived dopamine neurons
Authors: Park Chang‐Hwan , Minn Yang‐Ki , Lee Ji‐Yeon , Choi Dong Ho , Chang Mi‐Yoon , Shim Jae‐Won , Ko Ji‐Yun , Koh Hyun‐Chul , Kang Min Jeong , Kang Jin Sun , Rhie Duck‐Joo , Lee Yong‐Sung , Son Hyeon , Moon Shin Yong , Kim Kwang‐Soo , Lee Sang‐Hun 
Published: February 2005

AbstractHuman embryonic stem (hES) cells, due to their capacity of multipotency and self‐renewal, may serve as a valuable experimental tool for human developmental biology and may provide an unlimited cell source for cell replacement therapy. The purpose of this study was to assess the developmental potential of hES cells to replace the selectively lost midbrain dopamine (DA) neurons in Parkinson's disease. Here, we report the development of anin vitrodifferentiation protocol to derive an enriched population of midbrain DA neurons from hES cells. Neural induction of hES cells co‐cultured with stromal cells, followed by expansion of the resulting neural precursor cells, efficiently generated DA neurons with concomitant expression of transcriptional factors related to midbrain DA development, such as Pax2, En1 (Engrailed‐1), Nurr1, and Lmx1b. Using our procedure, the majority of differentiated hES cells (> 95%) contained neuronal or neural precursor markers and a high percentage (> 40%) of TuJ1+ neurons was tyrosine hydroxylase (TH)+, while none of them expressed the undifferentiated ES cell marker, Oct 3/4. Furthermore, hES cell‐derived DA neurons demonstrated functionalityin vitro,releasing DA in response to KCl‐induced depolarization and reuptake of DA. Finally, transplantation of hES‐derived DA neurons into the striatum of hemi‐parkinsonian rats failed to result in improvement of their behavioral deficits as determined by amphetamine‐induced rotation and step‐adjustment. Immunohistochemical analyses of grafted brains revealed that abundant hES‐derived cells (human nuclei+ cells) survived in the grafts, but none of them were TH+. Therefore, unlike those from mouse ES cells, hES cell‐derived DA neurons either do not survive or their DA phenotype is unstable when grafted into rodent brains.
Effects of hyperglycaemia on ocular development in rabbit: refraction and biometric changes
Authors: Herse Peter 
Published: February 2005

AbstractAim:  To determine the effect of acute and chronic hyperglycaemia on the refraction and development of the rabbit eye.Methods:  Ocular dimensions of five alloxan‐induced hyperglycaemic and six control rabbits were measured over 9 weeks using A scan biometry. Refraction was measured using retinoscopy. The animals were 10 weeks of age at the start of the experiment.Results:  The acute onset of hyperglycaemia was associated with a fast and stable 2 D hyperopic shift in refraction. Lens thickness increased during the first 2 weeks of hyperglycaemia, returned to near normal thickness after 3–5 weeks of hyperglycaemia and then decreased in thickness in the last 4 weeks of the study. The hyperopic refraction remained unchanged during changes in lens thickness. Nine weeks of hyperglycaemia was associated with a 25% reduction in the growth of both the globe and the lens and a 17% decrease in body mass compared with the controls.Conclusion:  The hyperopic refraction change of acute hyperglycaemia is likely to be because of a change in the refractive index of the cortical fibres of the lens and is the probable source of the fluctuating refraction seen in diabetic patients. Chronic hyperglycaemia reduced the axial development of the eye and is the probable source of the chronic hyperopic refraction seen in children with Type I diabetes.
The Dubbelman eye model analysed by ray tracing through aspheric surfaces
Authors: Norrby Sverker 
Published: February 2005

AbstractDubbelman and co‐workers have determined intraocular spacings and surface shapes in living eyes by means of corrected Scheimpflug images in a large number of subjects of different age at several levels of accommodation. They give relationships for key anterior segment parameters as a function of age and level of accommodation. These are used in this paper to build a schematic eye incorporating aspheric surfaces. This eye model is analysed by means of ray tracing with a technique developed for use with a common spreadsheet computer program. The Dubbelman eye model appears to be well corrected for spherical aberration. Compared with measurements on real eyes it agrees well in general, but spherical aberration is negative, while in real eyes it tends to be positive.
Vasovagal syncope evoked by needle phobia when inserting a contact lens*
Authors: Mimura Tatsuya , Funatsu Hideharu , Yamagami Satoru , Usui Tomohiko , Ono Kyoko , Araie Makoto , Amano Shiro 
Published: February 2005

AbstractPurpose:  To report a patient who fell unconscious because of vasovagal syncope evoked by needle phobia when he tried to wear contact lenses.Case reports:  A 16‐year‐old healthy boy had sometimes experienced dizziness when looking at the tips of pens. When he put his finger and the lens close to his eye to insert a soft contact lens, he felt sick and dizzy and fell unconscious.Conclusion:  Our experience suggests that patients with needle phobia may develop vasovagal syncope by concentrating on a fingertip when inserting a contact lens. We need to be aware of unconsciousness because of phobia when trying to insert contact lenses.
A comparison of colour micrographs obtained with a charged couple device (CCD) camera and a 35‐mm camera
Authors: Pedersen Mads Møller , Smedegaard Jesper , Jensen Peter Koch , Heegaard Steffen , Jensen Ove Aksel , Prause Jan Ulrik 
Published: February 2005

Abstract.Purpose:  The purpose of this study was to determine if micrographs produced with a colour charged couple device (CCD) camera were comparable in quality to micrographs obtained with a 35‐mm colour film camera. The Axiocam (Zeiss, Jena, Germany) CCD camera produced images of 3900 × 3090 pixels. Methods:  Each picture in a series of 50 pairs of film and digital micrographs was rated independently by each of three observers on the categories of colour, detail and overall impression. A total of 28 of the 50 pairs of micrographs were discarded due to colour differences. Results:  Digital micrographs were rated lower on colour and higher on detail compared to film micrographs. The film and digital micrographs were rated equally on overall impression. The difference in colour between film and digital micrographs can be compensated for using image processing software on the digital image. However, such manipulation was not carried out as part of the present study. The study originally included 50 digital micrographs and 50 film micrographs. The micrographs were paired and 22 of the 50 pairs of micrographs were assessed. Thus 28 pairs were not evaluated due to colour differences in the non‐manipulated pictures. The interobserver difference on colour in the remaining 22 pairs given as mean square ± standard error of the mean was − 0.27 ± 0.10, 0.62 ± 0.10 and 0.90 ± 0.11. The interobserver difference on detail was − 0.48 ± 0.10, 0.95 ± 0.10 and 1.43 ± 0.10. The interobserver difference on overall impression was − 0.70 ± 0.10, 0.57 ± 0.10 and 1.27 ± 0.10. All the results differed significantly (p < 0.001). Conclusion:  Digital micrographs are sufficient in detail, colour and overall impression to replace the traditional 35‐mm film recordings for use in histopathology.