bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signaling complex formation of phospholipase Cβ4 with metabotropic glutamate receptor type 1α and 1,4,5‐trisphosphate receptor at the perisynapse and endoplasmic reticulum in the mouse brain
Authors: Nakamura Michiko , Sato Kazunori , Fukaya Masahiro , Araishi Kenji , Aiba Atsu , Kano Masanobu , Watanabe Masahiko 
Published: December 2004

AbstractUpon activation of cell surface receptors coupled to the Gq subclass of G proteins, phospholipase C (PLC) β hydrolyses membrane phospholipid to yield a pair of second messengers, inositol 1,4,5‐trisphosphate (IP3) and 1,2‐diacylglycerol. PLCβ4 has been characterized as the isoform enriched in cerebellar Purkinje cells (PCs) and the retina and involved in motor and visual functions. Here we examined cellular and subcellular distributions of PLCβ4 in adult mouse brains. Immunohistochemistry showed that high levels of PLCβ4 were detected in the somatodendritic domain of neuronal populations expressing the metabotropic glutamate receptor (mGluR) type 1α, including olfactory periglomerular cells, neurons in the bed nucleus anterior commissure, thalamus, substantia nigra, inferior olive, and unipolar brush cells and PCs in the cerebellum. Low to moderate levels were detected in many other mGluR1α‐positive neurons and in a few mGluR1α‐negative neurons. In PCs, immunogold electron microscopy localized PLCβ4 to the perisynapse, at which mGluR1α is concentrated, and to the smooth endoplasmic reticulum in dendrites and spines, an intracellular Ca2+ store gated by IP3 receptors. In the cerebellum, immunoblot demonstrated its concentrated distribution in the post‐synaptic density and microsomal fractions, where mGluR1α and type 1 IP3 receptor were also greatly enriched. Furthermore, PLCβ4 formed coimmunoprecipitable complexes with mGluR1α, type 1 IP3 receptor and Homer 1. These results suggest that PLCβ4 is preferentially localized in the perisynapse and smooth endoplasmic reticulum as a component of the physically linked phosphoinositide signaling complex. This close molecular relationship might provide PLCβ4 with a high‐fidelity effector function to mediate various neuronal responses under physiological and pathophysiological conditions.
Extensive exercise is not harmful in amyotrophic lateral sclerosis
Authors: Liebetanz David , Hagemann Katrin , Von Lewinski Friederike , Kahler Elke , Paulus Walter 
Published: December 2004

AbstractWhether physical activity increases risk or promotes progression of motor neurone degeneration in amyotrophic lateral sclerosis (ALS) is still debated. Current pathophysiological hypotheses include excitotoxicity, oxidative stress and increased calcium loads as causes of selective degeneration of vulnerable motor neurones. Vigorous exercise might amplify these factors by increasing firing rates at motor neurones. To test this hypothesis, we constrained a transgenic mouse model of ALS overexpressing the mutant human form of the Cu/Zn superoxide dismutase‐1 (SOD‐1) to a lifetime exercise on motor‐driven running wheels for 10 h daily (active group, n = 12). Onset and progression of disease were assessed by grip strength, stride length and tight rope test. Data were compared with SOD‐1 mice placed in running wheels set to slow speed (sedentary group, n = 13). Untreated SOD‐1 mice were an additional control group (n = 12). We found no differences in disease onset, which was determined by a change‐point analysis using an iterative fitting of segmented linear regression models, or in disease progression. However, the running group showed a non‐significant 6‐day improvement in survival (133.7 ± 3.2 days) compared with the sedentary group (127.2 ± 3.2 days) and a 4‐day improvement compared with the control group (129.1 ± 2.5 days). We demonstrate that a lifetime of vigorous exercise does not promote onset or progression of motor degeneration in SOD‐1‐mediated ALS. Moreover, the results suggest that the level of excitatory input and calcium turnover at motor neurones, both of which should be increased by running activity, do not interfere with the pathophysiology of SOD‐1‐mediated ALS.
Homophilic interactions of chick neurofascin in trans are important for neurite induction
Authors: Pruss Thomas , Niere Marc , Kranz Eva Ursula , Volkmer Hansjürgen 
Published: December 2004

AbstractNeurofascin is a member of the immunoglobulin superfamily involved in axon extension and fasciculation. Here we apply adenoviral short hairpin RNA (shRNA) expression in primary neurons, PC12–NIH/3T3 co‐cultures in combination with Luminex® assays, to demonstrate homophilic interactions of neurofascin for neurite outgrowth. An adenoviral vector was constructed for the expression of shRNA in primary tectal cells that inhibits gene expression similar to short interfering RNA. We demonstrate that after shRNA‐mediated knockdown neuronal neurofascin expression is important for neurite outgrowth on a neurofascin substrate. Neurite outgrowth assays reveal that neurite formation of PC12 cells is increased when neurofascin is overexpressed on both outgrowing PC12 cells and substrate NIH/3T3 cells, suggesting that neurofascin expression is also sufficient for neurite induction. Luminex technology for the analysis of protein–protein interactions showed homophilic binding of neurofascin to itself.
Progressive abnormalities in skeletal muscle and neuromuscular junctions of transgenic mice expressing the Huntington's disease mutation
Authors: Ribchester Richard R. , Thomson Derek , Wood Nigel I. , Hinks Tim , Gillingwater Thomas H. , Wishart Thomas M. , Court Felipe A. , Morton A. Jennifer 
Published: December 2004

AbstractHuntington's disease (HD) is a neurodegenerative disorder with complex symptoms dominated by progressive motor dysfunction. Skeletal muscle atrophy is common in HD patients. Because the HD mutation is expressed in skeletal muscle as well as brain, we wondered whether the muscle changes arise from primary pathology. We used R6/2 transgenic mice for our studies. Unlike denervation atrophy, skeletal muscle atrophy in R6/2 mice occurs uniformly. Paradoxically however, skeletal muscles show age‐dependent denervation‐like abnormalities, including supersensitivity to acetylcholine, decreased sensitivity to µ‐conotoxin, and anode‐break action potentials. Morphological abnormalities of neuromuscular junctions are also present, particularly in older R6/2 mice. Severely affected R6/2 mice show a progressive increase in the number of motor endplates that fail to respond to nerve stimulation. Surprisingly, there was no constitutive sprouting of motor neurons in R6/2 muscles, even in severely atrophic muscles that showed other denervation‐like characteristics. In fact, there was an age‐dependent loss of regenerative capacity of motor neurons in R6/2 mice. Because muscle fibers appear to be released from the activity‐dependent cues that regulate membrane properties and muscle size, and motor axons and nerve terminals become impaired in their capacity to release neurotransmitter and to respond to stimuli that normally evoke sprouting and adaptive reinnervation, we speculate that in these mice there is a progressive dissociation of trophic signalling between motor neurons and skeletal muscle. However, irrespective of the cause, the abnormalities at neuromuscular junctions we report here are likely to contribute to the pathological phenotype in R6/2 mice, particularly in late stages of the disease.
Synergistic action of GABA‐A and NMDA receptors in the induction of long‐term depression in glutamatergic synapses in the newborn rat hippocampus
Authors: Pavlov Ivan , Riekki Ruusu , Taira Tomi 
Published: December 2004

AbstractWe show that activation of GABAA receptors (GABAARs) promotes induction of N‐methyl‐d‐aspartate (NMDA) receptor (NMDAR)‐dependent long‐term depression (LTD) of glutamatergic synapses in the newborn rat hippocampal area CA1 in a developmentally restricted manner. In the newborn rat hippocampus two mechanistically different types of LTD of glutamatergic synapses could be induced under similar experimental conditions. The form of the LTD induced depended on the stimulation protocol and on the age of the animal. Low‐frequency stimulation (1 Hz) with 100 stimuli induced a robust homosynaptic, reversible LTD at postnatal days 2–8 (P2–P8) but not at P14. This LTD was blocked by the NMDAR antagonist AP5 or by the GABAAR antagonist picrotoxin. Use of a low‐chloride solution in the patch pipette resulting in EGABA‐A < –70 mV blocked the NMDAR‐dependent LTD, whereas clamping the cell to –40 mV during induction rescued it. In addition, it was possible to induce LTD at P14 with 100 stimuli if the cells were clamped to –40 mV during induction. Low‐frequency stimulation with 900 stimuli induced a robust homosynaptic, reversible LTD both at P2–P8 and at P14. However, neither AP5 nor picrotoxin affected the LTD induced by 900 pulses at P2–P8. Instead, the 900 stimuli‐induced LTD was blocked by the metabotropic glutamate receptor antagonists when co‐applied with AP5. We suggest that during the first postnatal week postsynaptic depolarization provided by the activation of GABAARs shifts the threshold for the LTD induction, making the synapses more prone to activity‐induced plasticity. From the second postnatal week onwards, when the GABAA responses are already hyperpolarizing, different mechanisms for LTD induction prevail.
Living learning theory through My Fair Lady
Authors: Glenzer Holly 
Published: December 2004

AbstractIn My Fair Lady (Lerner & Lowe, 1956), the play, the renowned linguistics professor, Henry Higgins, attempts to instruct the common flower‐vendor, Eliza Doolittle, in proper English etiquette and speech. Revisit the colourful story from the perspective of a twenty‐first century instructional designer. Set in the 1910s, but written in the heyday of behaviourism, the play reflects the idea that behavioural change is the evidence of learning. As we analyse Professor Higgins's applied theory of learning and instruction, we find unique examples of behaviourism, cognitivism and constructivism at work in the instructional strategies and activities and in the good professor's interpretations of Ms Doolittle's actions and attitudes toward learning.
BCL‐2‐induced glioma cell invasiveness depends on furin‐like proteases
Authors: Wick Wolfgang , Wild‐Bode Christine , Frank Brigitte , Weller Michael 
Published: December 2004

AbstractMigration and invasion are prerequisites for the neoplastic phenotype of malignant glioma. Ectopic expression of BCL‐2 enhances migration and invasion of glioma cells and promotes their synthesis of transforming growth factor‐β2 (TGF‐β2). We here report that BCL‐2‐expressing cells show enhanced expression and activity of the proprotein convertase, furin, which processes metalloproteinases (MMP) and TGF‐β. Consistent with a biological role for a BCL‐2‐dependent increase in furin‐like protease (FLP) activity, BCL‐2‐expressing cells exhibit enhanced MMP activity. Both a pseudosubstrate furin inhibitor, decanoyl‐Arg‐Val‐Lys‐Arg‐chloromethylketone (dec‐RVKR‐cmk), or alpha 1‐anti‐trypsin Portland (PDX), a recombinant furin‐inhibitory protein, suppress constitutive and BCL‐2‐mediated MMP activity and invasion. This inhibition is not overcome by TGF‐β or hepatocyte growth factor (HGF). A neutralizing TGF‐β antibody attenuates, but not abrogates, the invasive properties conferred by exogenous expression of BCL‐2, whereas the MMP inhibitor o‐phenantroline (o‐PA) abolishes the pro‐invasive action of BCL‐2. Exogenous HGF results in enhanced, and expression of dominant‐negative ezrin in reduced, FLP activity, and dec‐RVKR‐cmk blunts the HGF‐induced expression of mature TGF‐β2. Consequently, HGF and BCL‐2 family proteins use a furin‐dependent pathway to promote invasion via TGF‐β and MMP in human malignant glioma cells and the pro‐invasive properties of TGF‐β require furin‐ dependent MMP activity.
Neurotrophin‐3‐induced production of nerve growth factor is suppressed in Schwann cells exposed to high glucose: involvement of the polyol pathway
Authors: Suzuki Takeshi , Sekido Hiromi , Kato Noriaki , Nakayama Yukiharu , Yabe‐Nishimura Chihiro 
Published: December 2004

AbstractDevelopment of hypesthesia, a loss of sensitivity to stimulation, is associated with impaired regeneration of peripheral sensory fibers, in which Schwann cells play a key role by secreting nerve growth factor (NGF). Recent clinical trials indicated that an inhibitor of aldose reductase (AR), the rate‐limiting enzyme in the polyol pathway, significantly improved hypesthesia in diabetic patients. The fact that AR is localized in Schwann cells led us to investigate the role of the polyol pathway in NGF production of isolated Schwann cells. Among various endogenous factors examined, increased production of NGF was demonstrated in the cells treated with neurotrophin‐3 (NT‐3) for 24 h. NT‐3‐induced NGF production was significantly suppressed when cells were cultured in the medium containing high glucose. In these cells, the levels of glutathione (GSH) and cAMP‐response element binding protein (CREB) were reduced, whereas the level of activated nuclear factor‐κB (NF‐κB) was elevated. These changes were abolished when an AR inhibitor fidarestat was included in the medium. NT‐3‐induced NGF production was further attenuated in the cells treated with an inhibitor of GSH synthesis. Together, the enhanced polyol pathway activity under high‐glucose conditions seems to elicit reduced NT‐3‐induced NGF production in Schwann cells. Enhanced oxidative stress linked to the polyol pathway activity may mediate this process.
Prostaglandin E2 and microsomal prostaglandin E synthase‐2 expression are decreased in the cyclooxygenase‐2‐deficient mouse brain despite compensatory induction of cyclooxygenase‐1 and Ca2+‐dependent phospholipase A2
Authors: Bosetti Francesca , Langenbach Robert , Weerasinghe Gayani R. 
Published: December 2004

AbstractWe previously demonstrated that brain cyclooxygenase (COX)‐2 mRNA and protein levels, and prostaglandin E2 (PGE2) level, are down‐regulated in cytosolic phospholipase A2 (cPLA2) ‐deficient mice. To further investigate the interaction between upstream and downstream enzymes involved in brain prostaglandin synthesis, we examined expression and activity of COX‐1, of different PLA2 enzymes and of prostaglandin E synthase (PGES) enzymes in COX‐2–/– mice. We found that the PGE2 level was decreased by 51.5% in the COX‐2–/– mice brains, indicating a significant role of COX‐2 in brain formation of PGE2. However, when we supplied exogenous arachidonic acid (AA) to brain homogenates, COX activity was increased in the COX‐2–/– mice, suggesting a compensatory activation of COX‐1 and an intracellular compartmentalization of the COX isozymes. Consistent with COX‐1 increased activity, brain expression of COX‐1 protein and mRNA also was increased. Activity and expression of cPLA2 and secretory PLA2 (sPLA2) enzymes, supplying AA to COX, were significantly increased. Also, the PGE2 biosynthetic pathway downstream from COX‐2 was affected in the COX‐2–/– mice, as decreased expression of microsomal prostaglandin E synthase‐2 (mPGES‐2), but not mPGES‐1 or cytosolic PGES, was observed. Overall, the data suggest that compensatory mechanisms exist in COX‐2–/– mice and that mPGES‐2 is functionally coupled with COX‐2.
Arrestin2 expression selectively increases during neural differentiation
Authors: Gurevich Eugenia V. , Benovic Jeffrey L. , Gurevich Vsevolod V. 
Published: December 2004

AbstractArrestins and G protein‐coupled receptor kinases (GRKs) are key players in homologous desensitization of G protein‐coupled receptors. Two non‐visual arrestins, arrestin2 and 3, and five GRKs (GRK2, 3, 4, 5 and 6) are involved in desensitization of many receptors. Here, we demonstrate a steady increase in arrestin2 expression during prenatal development. The density of arrestin2 mRNA is higher in differentiated areas as compared with proliferative zones, whereas arrestin3 mRNA shows the opposite distribution. At embryonic day 14, concentrations of arrestin proteins are similar (32–34 nm). Later in development, arrestin2 expression rises, leading to a fourfold excess of arrestin2 over arrestin3 at birth (48 vs. 11 ng/mg protein or 102 vs. 25 nm). Among GRKs, only GRK5 increased with embryonic age from 124 nmat E14 to 359 nmat birth. Similarly,in vitrodifferentiation of cultured precursor cells, neurospheres, leads to a significant up‐regulation of arrestin2 resulting in > 20‐fold excess of arrestin2 (160 vs. 7 nm). GRK5 is the only subtype increased with neurosphere differentiation, although the change is only about twofold. The data demonstrate selective increases in the expression of arrestin2 associated with neural development and suggest specific yet unappreciated roles for arrestin2 in neural differentiation.
Middle ear tumours with brainstem extension treated by ventral bulla osteotomy and craniectomy in two cats
Authors: Lucroy M. D. , Vernau K. M. , Samii V. F. , LeCouteur R. A. 
Published: December 2004

AbstractTwo geriatric domestic shorthaired cats (DSH) were treated surgically with a ventral bulla osteotomy and craniectomy for middle ear tumours that invaded the calvarium. Both cats had a history of vestibular disease. One cat had a normal neurological examination. Both cats underwent computed tomographic imaging of the head. After intravenous injection of an iodinated contrast material, one cat had a ring‐enhancing intracranial lesion and the other had a uniform contrast‐enhancing intracranial lesion, which either communicated with the bulla or was associated with bulla osseous lysis/production. One cat had a papillary adenoma and the other had an adenocarcinoma. Both cats had prolonged survivals (630 days; alive and lost to follow‐up at 840 days), which is longer than reported in cats with middle ear neoplasia. Craniectomy, in addition to ventral bulla osteotomy, may be part of the treatment plan for middle ear tumours that invade the calvarium.
Evaluation of telomerase‐targeted therapies in canine cancer cell lines
Authors: Argyle D. J. , McKevitt T. , Gault E. , Nasir L. 
Published: December 2004

AbstractDespite advances in conventional therapeutics, cancer remains an invariably fatal disease, the major challenge being to develop tumour‐specific cancer treatment strategies. Current treatments such as chemotherapy and radiotherapy rely on a crude distinction between cancer cells and normal cells. However, with an increased understanding of the molecular events in the development of cancer, it is possible that far more innovative and targeted approaches can be developed. From studies on humans and dogs, the enzyme telomerase has emerged as a central unifying mechanism underlying the immortal phenotype of cancer and has thus become a candidate for differentiating between normal and cancer cells. The level and frequency of telomerase activity and component gene expression in cancers reinforces this as a potential target for cancer therapies. This article describes two approaches to target cancer by capitalizing on the expression of this enzyme. In the first approach, we target the enzyme itself, the goal being to cause cancer cell death. In the second approach, we utilize the respective gene promoters for telomerase component enzymes to drive expression of a reporter gene in cancer cell lines. The results demonstrated that targeted gene expression using promoter elements can be achieved specifically in telomerase‐positive cell lines. However, targeting the enzyme itself proved less successful and warrants investigations into alternative approaches.
Treatment of canine haemangiosarcoma with suberoylanilide hydroxamic acid, a histone deacetylase inhibitor
Authors: Cohen L. A. , Powers B. , Amin S. , Desai D. 
Published: December 2004

AbstractA case report is presented by describing the treatment of a 12‐year‐old dog – diagnosed with haemangiosarcoma (HSA) – with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor. The drug was administered orally, on a daily basis, approximately 2 weeks post‐splenectomy at a dose of 3 mg kg−1. HSA is a lethal malignancy of the endothelium, which is usually disseminated by the time it is diagnosed. Median survival time, usually, is no longer than 80 days. Following treatment with SAHA, no sign of malignant growth could be discerned by means of diagnostic abdominal ultrasound, chest X‐ray or with the help of clinical symptoms, over a period of >1000 days. The precise mechanism by which HDAC inhibitors exert their anti‐cancer effects is uncertain, but evidence suggests that exposure to SAHA generates hyperacetylated chromosomal histones, which, in turn, facilitates the expression of tumour suppressor genes turned off by epigenetic mechanisms during neoplastic transformation of the endothelium.
Kinase inhibitors in cancer therapy
Authors: London C. 
Published: December 2004

AbstractOver the past few years, protein kinases have arisen as promising targets for therapeutic intervention in cancer therapy. This is due to a combination of several key events, including the identification of common kinase dysfunction in particular tumours and the recent success of such targeted kinase inhibitors as Gleevec (imatinib mesylate) and Iressa (Gefatinib). Ultimately, the success of this novel approach will be dependent on the careful identification and characterization of protein kinase dysregulation in particular forms of cancer. This review focuses on the function of protein kinases in normal cells, the mechanisms through which these kinases contribute to tumorigenesis, and the development and application of agents designed to inhibit dysfunctional kinases.
Promoting Evidence‐Based Practice: An Internship for Staff Nurses
Authors: Cullen Laura , Titler Marita G. 
Published: December 2004

ABSTRACTImplementing evidence‐based practice is a complex but valued process that requires support for nurses to make it a reality in care delivery. To address this, an Evidence‐Based Practice Staff Nurse Internship was developed at the University of Iowa Hospitals and Clinics in the United States. Program Overview: The objective of this internship is to promote use of evidence by staff nurses to improve patient outcomes. Through a competitive application process, six nurses are accepted in each cohort. The program provides didactic content and dedicated work time on topics interns select (e.g., family pet visitation, sedation management, bowel sounds assessment, guided imagery, family transition to pediatric floor). Interns receive paid clinical release time for participating. Roles and Responsibilities: Teams include the staff nurse, the nurse manager, and an advanced practice nurse. Responsibilities for each step are assigned to the person with the appropriate expertise. Evaluation: Interns report understanding the process, appreciate the opportunity for professional growth, and report their objectives are being met. Participants evaluated the program very positively and also provided recommendations for revision (e.g., revising class content). The program resulted in improved quality of care such as increased patient and family satisfaction, decreased length of stay, and cost savings. Implications: Programs that support practitioners through the evidence‐based practice process are needed for use in a variety of settings internationally. This unique program supports staff nurses in making evidence‐based practice a reality for their work and patients and might be transferable across settings.