bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method for cellular localization of gene expression via quantitative in situ hybridization in plants
Authors: Küpper Hendrik , Seib Laura Ort , Sivaguru Mayandi , Hoekenga Owen A. , Kochian Leon V. 
Published: March 2007

SummaryA quantitative in situ hybridization technique (quantitative whole‐mount in situ hybridization, QISH) for plants is described. It employs direct hybridization of fluorescently labelled gene‐specific oligonucleotides in large tissue pieces combined with optical sectioning. It dramatically increases the throughput compared with conventional antibody‐ and microtome‐based in situ mRNA hybridization methods, while simultaneously eliminating artefact‐prone preparation steps that prevent reliable quantification in conventional methods. The key feature of this technique is the quantification of gene expression using housekeeping genes (cytosolic GAPDH and 18S RNA) as internal standards. This feature enables a correction of varying cytoplasm/vacuole ratios in different cell types, as well as tissue optical effects and non‐specific signals. The quantitative nature of the technique allows for analysis of gene expression in response to different environmental conditions, as well as tissue‐ and age‐dependent differences in gene expression patterns. In addition to testing tissue permeabilization, structural preservation, specificity, linearity and tissue optical effects, we verified the reliability of the technique with three Arabidopsis thaliana genes of known function and distribution. These were the rbcL gene for ribulose 1,5‐bisphosphate carboxylase, the developmentally related gene SCARECROW (AtSCR) and PHOT‐1, a photoreceptor kinase. As expected, rbcL mRNA was found in all photosynthetic cells, while SCR mRNA was detected mainly in bundle sheath cells and PHOT‐1 was found predominantly in epidermal and cortical cells of the apical hook of light‐grown seedlings. As an application example, QISH was used to measure transcript abundance for a zinc transporter from the ZIP family of transporters in the Zn/Cd hyperaccumulator model plant, Thlaspi caerulescens, and the related non‐accumulator Thlaspi arvense. This showed that QISH can be used to compare differences in mRNA levels between cell types, plant growth conditions and plant species. Messenger RNA for the zinc transporter gene ZNT1 was abundant in photosynthetic cells, but not in the epidermal storage cells where metal hyperaccumulation in T. caerulescens occurs. This indicates that ZNT1 does not directly participate in metal hyperaccumulation within the leaf. Growing T. caerulescens with high zinc levels strongly reduced ZNT1 transcript abundance in the spongy mesophyll cells, but less in the other cell types. In T. arvense, ZNT1 mRNA levels were generally much lower, and were furthermore drastically reduced by growth at increased zinc levels, confirming earlier reports regarding ZNT1 regulation in these two Thlaspi species.
SDE5, the putative homologue of a human mRNA export factor, is required for transgene silencing and accumulation of trans‐acting endogenous siRNA
Authors: Hernandez‐Pinzon Inmaculada , Yelina Nataliya E. , Schwach Frank , Studholme David J. , Baulcombe David , Dalmay Tamas 
Published: March 2007

SummaryPost‐transcriptional gene silencing (PTGS) is a sequence‐specific RNA degradation process conserved in fungi, plants and animals. The trigger of the mechanism is double‐stranded RNA derived from transgenic or endogenous loci and formed by intra‐ or inter‐molecular interactions of single‐stranded RNAs or the action of RNA‐dependent RNA polymerases (RDRs). Double‐stranded RNA from various sources is processed by one of the four Dicer‐like (DCL) proteins in Arabidopsis, and the resulting short RNAs enter into at least four different pathways, one of which involves the production of trans‐acting short interfering RNAs (tasiRNAs). We report here a novel gene (SDE5) that is required for transgene silencing and the production of tasiRNAs. Mutation in SDE5 also results in hyper‐susceptibility to cucumber mosaic virus but not turnip mosaic virus. However, like RDR6, SDE5 is not involved in inverted repeat‐induced transgene silencing or the biogenesis of microRNAs and 24 nt siRNAs produced by DCL3. Based on these results, we propose that SDE5 acts together with RDR6 in generating double‐stranded RNA from specific single‐stranded RNAs. As the sequence of SDE5 has sequence features shared by TAP, a human mRNA export factor, we propose that its role could be in the transport of RNA molecules that are converted into a double‐stranded form by RDR6.
Complete or partial hippocampal damage produces equivalent retrograde amnesia for remote contextual fear memories
Authors: Lehmann Hugo , Lacanilao Samuel , Sutherland Robert J. 
Published: March 2007

AbstractWe examined the effects of partial or complete damage to the hippocampus on long‐term retention of a Pavlovian conditioned fear response to context. Rats received a single contextual fear‐conditioning episode and 1 week, 3 months or 6 months later they received sham, partial (dorsal) or complete NMDA‐induced damage of the hippocampus. During a retention test conducted 2 weeks after surgery, the control rats exhibited high levels of freezing in the context, although their level of freezing was significantly lower with longer retention intervals. Rats with complete hippocampal damage displayed very little freezing in the context at each learning–surgery interval. Partial hippocampal damage caused a smaller but consistent deficit in conditioned responding, especially at longer learning–surgery intervals. Neither group of hippocampus‐damaged rats showed less retrograde amnesia for more remote memories. We found that the severity of retrograde amnesia for contextual fear conditioning following hippocampal damage is related to the extent of the damage and that there is consistent and severe retrograde amnesia for even remote contextual fear memories. These findings support the idea that the hippocampal formation has an essential and long‐lasting, possibly permanent, role in memory for contexts.
Neurotrophins modulate neuron–glia interactions at a vertebrate synapse
Authors: Todd Keith J. , Auld Daniel S. , Robitaille Richard 
Published: March 2007

AbstractNeurotrophins are important modulators of synaptic function at both developing and mature synapses in the CNS and PNS. At the neuromuscular junction (NMJ), neurotrophins, as well as perisynaptic Schwann cells (PSCs) are critical for the long‐term maintenance and stability of the synapse. Considering this correlation and the acute interactions that occur at the synapse between PSCs and the nerve terminal, we wondered if neurotrophins could also be involved in neuron‐glia signalling. To test if neurotrophins were able to signal to PSCs we used brief applications of neurotrophin‐3 (NT‐3), brain‐derived neurotophic factor (BDNF) or nerve growth factor (NGF; 100 ng/mL). Soleus muscles of mice were incubated with the Ca2+ indicator Fluo‐4AM and Ca2+ responses in PSCs were elicited through nerve stimulation (50 Hz, 30 s). Our results indicate that acute application of both NT‐3 and BDNF, but not NGF, increased PSC Ca2+ responses. Investigation of the mechanisms involved in these increases revealed distinct pathways for BDNF and NT‐3. BDNF increased PSC responsiveness through potentiation of ATP responses while NT‐3 modulated muscarinic acetylcholine receptor signalling. Using local applications of the neurotrophins, we found that both neurotrophins were able to elicit Ca2+ responses in PSCs where BDNF used a phospholipase C–inositol 1,4,5‐triphosphate (PLC‐IP3) mechanism, while NT‐3 required extracellular Ca2+. Our results demonstrate a neurotrophin‐dependent modulation of neuron‐glia signalling through differential mechanisms employed by NT‐3 and BDNF. Hence, neurotrophins precisely and differentially regulate PSC functions through modulation of either purinergic or cholinergic signalling pathways.
Intrapartum amnioinfusion for meconium‐stained amniotic fluid: a systematic review of randomised controlled trials
Authors: Xu H , Hofmeyr J , Roy C , Fraser WD 
Published: March 2007

Background  Amnioinfusion (AI) is thought to dilute meconium when present in the amniotic fluid and so reduces the risk of meconium aspiration.Objectives  To evaluate if AI reduces meconium aspiration syndrome (MAS) and other indicators of morbidity in babies born to women with meconium‐stained amniotic fluid (MSAF).Search strategy  PubMed, Medline, EMBASE, and the Cochrane Controlled Trials Register from January 1980 to May 30, 2005, using the keywords ‘amnioinfusion’ and ‘meconium’.Selection criteria  Randomised trials comparing AI with no AI for women in labour with MSAF. Trial quality was evaluated using pre‐established criteria.Data collection and analysis  The following morbidity indicators were assessed: MAS, 5‐minute Apgar score < 7, arterial cord pH < 7.2, and caesarean section. Studies were stratified according to the level of peripartum surveillance (standard versus limited). Typical relative risks (RRs) with their 95% confidence intervals were calculated for each outcome using a random effects model.Main results  In clinical settings with standard peripartum surveillance, we found no evidence that AI reduced the risk of MAS (RR 0.59, 95% CI 0.28–1.25), 5‐minute Apgar score < 7 (RR 0.90, 95% CI 0.58–1.41), or caesarean delivery (RR 0.89, 95% CI 0.73–1.10). In clinical settings with limited peripartum surveillance, AI appeared to reduce the risk of MAS (RR 0.25, 95% CI 0.13–0.47).Conclusion  In clinical settings with standard peripartum surveillance, the evidence does not support the use of AI for MSAF. In settings with limited peripartum surveillance, where complications of MSAF are common, AI appears to reduce the risk of MAS. However, this finding requires confirmation by further studies.
Maternal serum screening for Down syndrome: are women’s perceptions changing?
Authors: Gidiri M , McFarlane J , Holding S , Lindow SW 
Published: March 2007

Objectives  To document trends in serum screening for Down's syndrome.Background  Trends in the uptake of serum screening for Down syndrome have not been documented in a UK population.Design  A retrospective review of the rate of uptake in a unit that has offered serum screening for Down syndrome to all pregnant women.Setting  A large north of England hospital that has offered universal Down syndrome screening using the ‘triple test’ since 1992.Patients  A total of 47 998 women who booked for antenatal care.Main outcome measures  Uptake of serum screening for Down syndrome.Methods  The results of the screening programme were contemporaneously recorded on a computer database, and the study team accessed the data.Results  There was a significant reduction in the uptake of serum screening for Down syndrome from a maximum of 82.6% in 1993 to 41.4% in 2005. There was a significant but small trend upwards in the age of women accepting screening and also a significant trend in the increase in the screen‐positive rates.Conclusions  The reduction in uptake of Down syndrome screening over the past 13 years must be taken into account when planning a screening programme. Other units should be encouraged to review their rate of uptake to determine if our data are representative of a wider trend.
Alternative isoforms of myelin/oligodendrocyte glycoprotein with variable cytoplasmic domains are expressed in human brain
Authors: Allamargot Chantal , Gardinier Minnetta V. 
Published: March 2007

AbstractThe human myelin/oligodendrocyte glycoprotein (MOG) gene is encoded by 10 exons that exhibit a complex pattern of alternative splicing. This report demonstrates that several MOG‐specific alternative splice variants are indeed expressed in human oligodendrocytes (OLs) and myelin during perinatal development and are retained through adulthood. While all forms possess the common extracellular Ig‐like domain, these alternative MOG structures differ significantly in their respective cytoplasmic domains. Peptide‐specific antibodies were generated to facilitate detection of these different MOG moieties. The fidelity of these antibodies is shown using N20 OLs expressing individual MOG variants. These antibodies also only co‐localize with another well‐characterized marker of OLs and myelin – PLP/DM20 proteins. Among the human tissue samples tested, very limited expression occurred by 36 weeks gestation for 2–3 MOG variants, and the remaining MOG isoforms were not evident until shortly after birth. This study represents the first evidence of alternative translation products from the MOG gene. To date, it is believed that alternative splicing of MOG is limited to primates. Recent completion of various genome projects has revealed that alternative splicing is much more prevalent than originally estimated, and species‐specific alternative splicing is now being shown to be highly relevant to expanding proteomic diversity.
Molecular identification and functional role of voltage‐gated sodium channels in rat carotid body chemoreceptor cells. Regulation of expression by chronic hypoxia in vivo
Authors: Caceres Ana I. , Obeso Ana , Gonzalez Constancio , Rocher Asuncion 
Published: March 2007

AbstractWe have assessed the expression, molecular identification and functional role of Na+ channels (Nav) in carotid bodies (CB) obtained from normoxic and chronically hypoxic adult rats. Veratridine evoked release of catecholamines (CA) from an in vitro preparation of intact CBs obtained from normoxic animals, the response being Ca2+ and Na+‐dependent and sensitive to tetrodotoxin (TTX). TTX inhibited by 25–50% the CA release response evoked by graded hypoxia. Immunoblot assays demonstrated the presence of Navα‐subunit (c. 220 kDa) in crude homogenates from rat CBs, being evident an up‐regulation (60%) of this protein in the CBs obtained from chronically hypoxic rats (10% O2; 7 days). This up‐regulation was accompanied by an enhanced TTX‐sensitive release response to veratridine, and by an enhanced ventilatory response to acute hypoxic stimuli. RT‐PCR studies demonstrated the expression of mRNA for Nav1.1, Nav1.2, Nav1.3, Nav1.6 and Nav1.7 isoforms. At least three isoforms, Nav1.1, Nav1.3 and Nav1.6 co‐localized with tyrosine hydroxylase in all chemoreceptor cells. RT‐PCR and immunocytochemistry indicated that Nav1.1 isoform was up‐regulated by chronic hypoxia in chemoreceptor cells. We conclude that Nav up‐regulation represents an adaptive mechanism to increase chemoreceptor sensitivity during acclimatization to sustained hypoxia as evidenced by enhanced ventilatory responses to acute hypoxic tests.
Pituitary adenylate cyclase‐activating polypeptide (PACAP) stimulates the oxygen sensing type I (glomus) cells of rat carotid bodies via reduction of a background TASK‐like K+current
Authors: Xu Fenglian , Tse Frederick W. , Tse Amy 
Published: March 2007

AbstractPituitary adenylate cyclase‐activating polypeptide (PACAP)‐deficient mice are prone to sudden neonatal death and have reduced respiratory response to hypoxia. Here we found that PACAP‐38 elevated cytosolic [Ca2+] ([Ca2+]i) in the oxygen sensing type I cells but not the glial‐like type II (sustentacular) cells of the rat carotid body. This action of PACAP could not be mimicked by vasoactive intestinal peptide but was abolished by PACAP 6‐38, implicating the involvement of PAC1receptors. H89, a protein kinase A (PKA) inhibitor attenuated the PACAP response. Simultaneous measurement of membrane potential and [Ca2+]ishowed that the PACAP‐mediated [Ca2+]irise was accompanied by depolarization and action potential firing. Ni2+, a blocker of voltage‐gated Ca2+channels (VGCC) or the removal of extracellular Ca2+reversibly inhibited the PACAP‐mediated [Ca2+]irise. In the presence of tetraethylammonium (TEA) and 4‐aminopyridine (4‐AP), PACAP reduced a background K+current. Anandamide, a blocker of TWIK‐related acid‐sensitive K+(TASK)‐like K+channel, occluded the inhibitory action of PACAP on K+current. We conclude that PACAP, acting via the PAC1receptors coupled PKA pathway inhibits a TASK‐like K+current and causes depolarization and VGCC activation. This stimulatory action of PACAP in carotid type I cells can partly account for the role of PACAP in respiratory disorders.
17β‐estradiol does not protect cerebellar granule cells from excitotoxicity or apoptosis
Authors: Miñano Alfredo , Cerbón Marco Antonio , Xifró Xavier , Malagelada Cristina , Aguilera José , Rodríguez‐Alvarez José 
Published: March 2007

AbstractMounting evidences have suggested that 17β‐estradiol (E2) could have a neuroprotective action in the CNS. In the present study, we wanted to study whether this estrogen was able to protect cerebellar granule cells (CGCs) from apoptosis or excitotoxicity. Our results suggest that E2 has no anti‐apoptotic effect in CGCs cultures. The lack of phosphoinositide 3‐kinase/Akt pathway activation in CGCs cultures could be on the basis of the failure of estradiol to protect CGCs from potassium‐deprivation and ceramide‐mediated apoptosis. Moreover, E2 does not protect CGCs from glutamate‐mediated death despite activating the extracellular signal regulated kinase kinase/extracellular signal regulated kinase pathway, which suggests that extracellular signal regulated kinase kinase/extracellular signal regulated kinase pathway activation is not sufficient to sustain an estrogen‐mediated neuroprotective effect in CGCs cultures. By contrast, we found that the estrogen had a significant neuroprotective effect against hydrogen peroxide‐mediated neuronal death. This effect was due to the antioxidant properties of the chemical structure of estradiol, as the biological inactive isomer 17α‐estradiol was also able to reduce hydrogen peroxide‐mediated neuronal death.
Apocynin alleviated hepatic oxidative burden and reduced liver injury in hypercholesterolaemia
Authors: Lu Long‐Sheng , Wu Chau‐Chung , Hung Li‐Man , Chiang Meng‐Tsan , Lin Ching‐Ting , Lin Chii‐Wann , Su Ming‐Jai 
Published: March 2007

AbstractBackground: This study addressed the effects of apocynin, a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, on hepatic oxidative burden and liver injury during diet‐induced hypercholesterolaemia.Methods and Results: Male Wistar rats were fed a 4% cholesterol‐enriched diet for 3 weeks. Apocynin was administered in drinking water concurrently. The high‐cholesterol diet (HC) significantly increased the serum level of cholesterol and hepatic cholesterol ester deposition, and these parameters were similar between the HC and high‐cholesterol diet plus apocynin (HCA) groups. The HC group showed abnormal liver function tests [alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (Alk‐P)] as well as increased Evans blue extravasation and macrophages infiltration. Apocynin treatment could suppress these inflammation‐related parameters. In vivo measurement of NADPH‐derived cellular autofluorescence suggested that HC increased oxidative stress in hepatocytes. Biochemical analysis of redox status including thiobarbituric acid reactive substances, reduced glutathione, and oxidized glutathione also confirmed the phenomenon. Apocynin treatment was able to alleviate these indices of oxidative burden owing to HC. Furthermore, apocynin‐abrogated HC induced gp91phox expression, suggesting the involvement of NADPH oxidase in the pathogenesis.Conclusions: We concluded that apocynin suppressed NADPH oxidase activation and subsequent liver injuries owing to high‐cholesterol intake in rats. The impacts of cholesterol metabolism disorders on pathogenesis and progression of steatohepatitis warrant further clinical investigation.
Hepatic stellate cell‐targeted delivery of M6P‐HSA‐glycyrrhetinic acid attenuates hepatic fibrogenesis in a bile duct ligation rat model
Authors: Luk John M. , Zhang Qi‐Sheng , Lee Nikki P. , Wo Jana Y. , Leung Pauline P. , Liu Ling‐Xiao , Hu Mei‐Yu , Cheung Kwok‐Fan , Hui Chee‐Kin , Lau George K. , Fan Sheung‐Tat 
Published: March 2007

AbstractBackground/Aims: Hepatic stellate cells (HSCs) play a key role in fibrogenesis. Here, we used mannose‐6‐phosphate‐modified human serum albumin (M6P26‐HSA) as a selective carrier to deliver antifibrotic drug 18β‐glycyrrhetinic acid (18β‐GA) in experimental fibrosis animals, and tested its effect in injured liver tissues.Methods: Bile duct ligation (BDL) was performed to induce liver damage in rats. Masson's stain and immunocytochemistry were used to assess hepatic collagen deposits and uptakes of M6P26‐HSA‐GA in HSCs in rat livers. Gene expression profiles of procollagen type I α2, smooth muscle actin (SMA), and transforming growth factor‐β1 (TGF‐β1) were analysed by TaqMan and quantitative polymerase chain reaction assays. The depositions of M6P26‐HSA‐GA in the HSC‐T6 cell line and primary HSCs were assessed by immunofluorescent staining.Results: Treatment with M6P26‐HSA‐GA at 10 mg/kg (three times/week for 2 weeks), but not the equivalent doses of free 18β‐GA and M6P26‐HSA carrier alone, could significantly attenuate collagen deposits in BDL rat liver. Masson's stain and TaqMan assay revealed significant modulation of procollagen type I α2 in the BDL‐injured liver. The depositions of M6P26‐HSA‐GA in HSCs were revealed by immunostaining with HSA and SMA markers. M6P26‐HSA bound activated HSCs in vitro and the immunoreactivity of M6P26‐HSA‐GA was detected in the cytoplasm and cell surface of HSCs and HSC‐T6 cells. The gene transcript levels of SMA and TGF‐β1 were modulated in HSC‐T6 cells treated with M6P26‐HSA‐GA.Conclusions: The M6P26‐HSA holds promise as a targeting carrier for the liver or HSCs, which may be used to deliver 18β‐GA as a therapeutic agent to treat liver fibrosis.
Cerebrospinal fluid and serum prolactin in systemic lupus erythematosus with and without central nervous system involvement
Authors: DAI Lie , WU Yimei , ZHENG Donghui , HAN Zhijuan , CHEN Lan X. , SCHUMACHER H. Ralph 
Published: March 2007

AbstractAim: Recent research has shown that prolactin (PRL) may participate in the pathogenesis of systemic lupus erythematosus (SLE) and hyperprolactinemia may be related to disease activity. The current study investigated both serum and cerebrospinal fluid (CSF) PRL in SLE patients and their possible relationship to central nervous system (CNS) involvement.Methods: Prolactin levels were determined by immunoradiometric assay. Serum PRL levels were detected in 80 patients with SLE and 25 matched healthy controls. Disease activity was scored by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). CSF PRL levels were detected in seven cases of CNS involving SLE, eight cases of non‐CNS involved inactive SLE and eight cases of non‐SLE CNS disorders.Results: Hyperprolactinemia was present in 40% of SLE patients. Serum PRL levels were significantly correlated with SLEDAI scores. There was no significant difference in serum PRL levels between SLE patients with or without CNS involvement, but the mean CSF PRL levels were higher in CNS‐involved SLE patients than in non‐CNS‐involved SLE and non‐SLE patients. There was no significant correlation between serum and CSF PRL levels.Conclusions: Our results suggest that high serum PRL levels correlate with active disease in SLE, but not with CNS involvement. CSF PRL levels in SLE patients correlate with CNS involvement, which indicates that CSF PRL may be involved in the pathogenesis of CNS‐SLE.