bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a Digitonin‐Solubilized Bovine Brain H3 Histamine Receptor Coupled to a Guanine Nucleotide‐Binding Protein
Authors: Zweig Adam , Siegel Marvin I. , Egan Robert W. , Clark Mike A. , Shorr Robert G. L. , West Robert E.
Published: October 2006

Abstract: The H3 receptor is a high‐affinity histamine receptor that inhibits release of several neurotransmitters, including histamine. We have characterized H3 receptor binding in bovine brain and developed conditions for its solubilization. Particulate [3H]histamine binding showed an apparently single class of sites (KD= 4.6 nM; Bmax= 78 fmol/mg of protein). Of the detergents tested, digitonin at a detergent/protein ratio of 1:1 (wt/wt) yielded the greatest amount of solubilized receptors, typically 15–30% of particulate binding. Neither equilibrium binding of [3H]histamine to receptors (KD= 6.1 nM; Bmax= 92 fmol/mg of protein) nor the inhibitor profile was substantially altered by digitonin solubilization. However, solubilization did increase the rate of [3H]histamine association with and dissociation from the receptor. Size‐exclusion chromatography indicated an apparent molecular weight of 220,000 for the solubilized receptor, and peak binding from this column retained its guanine nucleotide sensitivity. These last two observations are consistent with the solubilized receptor occurring in complex with a guanine nucleotide‐binding protein.
Modulation by GTP of Basal and Agonist‐Stimulated Striatal Adenylate Cyclase Activity Following Chronic Blockade of D1 and D2 Dopamine Receptors: Involvement of G Proteins in the Development of Receptor Supersensitivity
Authors: Schettini Gennaro , Ventra Carmelo , Florio Tullio , Grimaldi Maurizio , Meucci Olimpia , Marino Adriano
Published: October 2006

Abstract: Rats receiving injections of specific antagonists of dopamine receptors (SCH 23390 for D1, haloperidol for D2, and haloperidol + SCH 23390) once daily for 21 days develop a selective supersensitivity of the blocked receptors. To study the molecular correlates of these adaptive changes, we evaluated the involvement of GTP‐binding proteins in the development of supersensitivity of dopamine receptors. By means of adenylate cyclase studies, we tested whether any of the treatments modified the functional response to GTP in striata dissected from control and treated rats. Our data show that the chronic blockade of D1 and/or D2 receptors potentiates both basal and dopamine receptor‐stimulated adenylate cyclase activity in response to GTP. D1 receptor up‐regulation correlates with an increased adenylate cyclase response to GTP, whereas D2 receptor up‐regulation is accompanied by an enhanced GTP‐induced inhibition of enzyme activity, in both basal and receptor‐activated conditions. This potentiation does not seem to match the changes in mRNA content of Gs and Giã subunits. Unexpectedly, however, a significant increase in Giã subunit mRNA was found after the chronic blockade of D1 receptors; this result could be explained by cross‐regulation between GTP‐binding protein‐mediated pathways. This cross‐regulation could serve as a protective mechanism whereby cells exposing up‐regulated receptors protect themselves from a condition of hyperactivity of the adenylate cyclase enzyme.
Insulin‐Like Growth Factor I Receptor Binding in Brains of Alzheimer's and Alcoholic Patients
Authors: Crews F. T. , McElhaney R. , Freund G. , Ballinger W. E. , Raizada Mohan K.
Published: October 2006

Abstract: Patients with chronic alcoholism and/or Alzheimer's disease show degenerative changes in the cerebral cortex and hippocampus. To investigate possible changes in insulin‐like growth factor I receptor binding sites in brain tissue of patients with these pathological conditions, the number of 125I‐insulin‐like growth factor I binding sites was determined in tissues obtained from control patients and those with Alzheimer's and/or with a history of alcoholism. The four experimental groups examined consisted of patients from similar age groups. Postmortem histology and a clinical history were used for the diagnosis of Alzheimer's disease and alcoholism, respectively. Careful clinical records were kept concerning other variables such as immediate cause of death and medications administered before death. Specific binding of 125I‐insulin‐like growth factor I to homogenates prepared from cerebral cortex of Alzheimer's, alcoholic, alcoholic Alzheimer's, and age‐matched control patients was similar, although Alzheimer's patients tended to have slightly higher binding values. No significant differences in insulin‐like growth factor I binding in cerebral cortex were found with regard to age of patients, the interval between death and autopsy, and CNS‐active medications. No statistical differences in 125I‐insulin‐like growth factor I binding were noted in hippocampal tissue from the four patient groups. Thus, human insulin‐like growth factor I binding sites in cerebral cortex and hippocampus appear unaffected by several variables.
Effect of Histamine H2 Receptor Antagonists on the Secretion of Cerebrospinal Fluid in the Cat
Authors: Naveh Yehezkel , Kitzes Ruth , Lemberger Anshel , Ben‐David Shlomit , Feinsod Moshe
Published: October 2006

Abstract: Following a recent report that epithelial cells of the choroid plexus possess histamine H2 receptors, the effect of cimetidine and ranitidine, histamine H2 receptor antagonists, on the secretion and electrolyte content of CSF was examined. Fifty cats were divided into one control (n = 6) and six experimental groups. CSF was collected by puncture of the cisterna magna following pentobarbital anesthesia, and its volume, concentrations of Na+, K+, Cl‐, and pH were determined. Cimetidine or ranitidine (50, 20, or 10 mg/kg) was injected intravenously 2 h after the start of the test, and their concentrations were measured in hourly blood samples and in 30‐min aliquots of CSF in the 50 mg/kg experimental groups. Whereas the secretion of CSF did not change over 6 h in the control group, it decreased significantly by 30–60 min after injection of cimetidine or ranitidine and remained low for the following 61/2 h in all experimental groups except the 10‐mg ranitidine group. Peak cimetidine and ranitidine concentrations in CSF in the 50‐mg experimental groups were noted 60 and 90 min, respectively, after intravenous injection. CSF electrolyte concentrations and pH did not change during the test in any group. We conclude that intravenous cimetidine or ranitidine can significantly reduce CSF secretion in the cat, possibly by competitive inhibition of the histamine effect on H2 receptors located on the choroid plexus epithelial cell, or by a direct effect on the capillaries of the choroid plexus.
Multiple Forms of Tyrosine Hydroxylase in Human Neuroblastoma Cells: Quantitation with Isoform‐Specific Antibodies
Authors: Haycock John W.
Published: October 2006

Abstract: Human tyrosine hydroxylase (HTH) RNA undergoes alternative splicing, and four different forms of HTH mRNA have been previously identified. Rabbit antibodies were raised against octapeptides unique to each of the four isoforms of HTH predicted from these mRNAs. Blot immunolabeling of human adrenal medulla, pheochromocytoma, and several neuroblastoma cell lines with affinitypurified anti‐HTH peptide antibodies demonstrated the presence of all four HTH isoforms in each of these tissues. Quantitative immunolabeling assays for HTH‐1, ‐2, and ‐4 were established, and HTH isoform levels were determined in several human neuroblastoma cell lines. Whereas total HTH levels differed up to fourfold among the HTH‐positive neuroblastoma cell lines studied [LA‐N‐1, LA‐N‐5, CHP‐234, BE(2)‐C, and BE(2)‐M17], the relative abundances of HTH isoforms in each of the cell lines were similar. Immunocytochemical analyses demonstrated that HTH immunoreactivity was distributed unequally among the cells in each of these neuroblastoma lines, and morphological interconversion did not account for this heterogeneity. A direct relationship between the percentage of HTH‐positive cells and overall HTH levels was also observed. This relationship, in the absence of an apparent clonal basis for the heterogeneity, suggests that HTH expression in neuroblastoma cells may be controlled in a relatively “all‐ornone”(bimodal) fashion.
Expression of Myelin Protein Genes and Other Myelin Components in an Oligodendrocytic Cell Line Conditionally Immortalized with a Temperature‐Sensitive Retrovirus
Authors: Verity A. N. , Bredesen D. , Vonderscher C. , Handley V. W. , Campagnoni A. T.
Published: October 2006

Abstract: We have conditionally immortalized oligodendrocytes isolated from normal and shiverer primary mouse brain cultures through the use of the retroviral vector ZIPSVtsA58. This vector encodes an immortalizing thermolabile simian virus 40 large T antigen (Tag) and allows for clonal selection by conferring neomycin (G418) resistance. We isolated 14 shiverer and 10 normal lines that expressed the early oligodendrocyte marker 2′,3′‐cyclic nucleotide 3′‐phosphodiesterase mRNA. These cell lines grew continuously at the permissive temperature (34°C) and displayed Tag nuclear immunostaining. On shifting to nonpermissive temperatures (39°C), the cells showed rapid arrested cell growth and loss of Tag staining. One line (N20.1) engineered from normal oligodendrocytes also expressed myelin basic protein (MBP) and proteolipid protein (PLP) mRNAs, genes normally expressed by mature, differentiated oligodendrocytes. No differences in any of the myelin‐specific protein mRNA levels were observed in N20.1 cells grown at 39°C for >9 days compared with cells maintained at 34°C. Immunocytochemical staining revealed N20.1 cells to be positive for the oligodendrocyte surface markers—galactocerebroside, A007, and A2B5. However, MBP and PLP polypeptides could not be detected by western blot or immunocytochemical staining at either the permissive or nonpermissive temperature. Cell‐free protein synthesis experiments indicated that the MBP mRNAs isolated from N20.1 cells were translatable and directed the synthesis of the 17‐, 18.5‐, and 21.5‐kDa MBP isoforms. Analysis of the PLP/DM20 gene splice products by polymerase chain reaction indicated that the expression of DM20 mRNA predominated over that of PLP mRNA in this cell line. Because the cell line expressed the MBP and PLP genes, it represents a “mature” oligodendrocyte, but the splicing patterns of these genes indicate that it is at an early stage of “maturation’. This cell line has now been passaged >40 times with fidelity of phenotype and genotype.
Prostaglandins Stimulate Serotonin Acetylation in Chick Pineal Cells: Involvement of Cyclic AMP‐Dependent and Calcium/Calmodulin‐Dependent Mechanisms
Authors: Voisin P. , Van Camp G. , Pontoire C. , Collin J. P.
Published: October 2006

Abstract: The effects of prostaglandins (PGs) on the activity of the rate‐limiting enzyme of melatonin biosynthesis, aryl‐alkylamine‐N‐acetyltransferase (NAT) were investigated on primary cultures of dispersed chick pineal cells. In indomethacin‐treated cells, PGs caused a four‐fold increase in NAT activity. This response was associated with an eightfold increase in cyclic AMP (cAMP) levels. The potency order of PGs was the same for NAT and for cAMP responses (PGE1 > PGE2 > PGF2α≫ cloprostenol). However, each PG tested was 30‐ to 200‐fold more potent to increase NAT activity than to stimulate cAMP accumulation. As a result, half‐maximal stimulation of NAT by PGs was not associated with an increase in cAMP levels. Half‐maximal stimulation of NAT by PGE1 was highly sensitive to inhibition by a calcium/calmodulin antagonist (W‐7). In contrast, maximal stimulation of NAT by PGE1 as well as stimulations evoked by either forskolin or 8‐bromo‐cAMP were poorly sensitive to inhibition by W‐7. These results indicate that an increase in cAMP levels may be responsible for the maximal stimulation of NAT evoked by PGs, whereas half‐maximal stimulation of NAT by PGs would rely principally on a calcium/calmodulin‐dependent mechanism.
Release‐Regulating Serotonin 5‐HT1D Autoreceptors in Human Cerebral Cortex
Authors: Maura Guido , Thellung Stefano , Andrioli Gian Carlo , Ruelle Antonio , Raiteri Maurizio
Published: October 2006

Abstract: Release‐regulating 5‐hydroxytryptamine (5‐HT) autoreceptors in the rat brain belong to the 5‐HT1B subtype. On the other hand, the human brain seems to lack 5‐HT1B receptors. In the present work 5‐HT autoreceptors present in human brain were characterized pharmacologically. Synaptosomes prepared from biopsy samples of human neocortex were labeled with [3H]5‐HT and exposed in superfusion to selective 5‐HT receptor agonists and antagonists during K+ depolarization. The rank order of potency of agonists as inhibitors of the [3H]5‐HT overflow was 5‐HT > sumatriptan (5‐HT1D/1B) > 8‐hydroxy‐2‐(di‐n‐propylamino)tetralin (5‐HT1A/1D) ≫ 1‐(2,5‐dimethoxy‐4‐iodophenyl)‐2‐aminopropane HCl (5‐HT2/1C). The effect of 5‐HT was insensitive to ketanserin (5‐HT2) but antagonized by methiothepin (5‐HT1/2) or by metergoline (5‐HT1C/1D). The data are compatible with a classification of the human 5‐HT autoreceptor as being of the 5‐HT1D subtype.
Amino Acid Levels in the Cerebrospinal Fluid of Newly Diagnosed Epileptic Patients: Effect of Vigabatrin and Carbamazepine Monotherapies
Authors: Kälviäinen Reetta , Halonen Toivo , Pitkänen Asla , Riekkinen Paavo J.
Published: October 2006

Abstract: We studied the CSF amino acid levels of 42 patients with newly diagnosed epilepsy before treatment with antiepileptic medication and during monotherapy with either vigabatrin or carabamzepine. The present study shows that patients with newly diagnosed epilepsy have elevated levels of the excitatory amino acid glutamate in CSF. Vigabatrin monotherapy effectively prevents the appearance of seizures in patients with high baseline CSF glutamate levels. In these patients, vigabatrin not only elevates the levels of γ‐aminobutyric acid, but also decreases the elevated levels of glutamate in CSF, which may also be important to the antiepileptic efficacy of vigabatrin. Patients with low CSF glutamate levels did not benefit from vigabatrin‐induced changes in amino acid levels and successful monotherapy with carbamazepine did not affect CSF amino acid levels. The elevation of γ‐aminobutyric acid is thus not the only way to achieve seizure control and there are several factors underlying the generation and control of seizures. Follow‐up of the patients with high baseline glutamate CSF levels will show if the observed abnormalities are related to the severity of epilepsy in individual patients and if early treatment with vigabatrin of these patients could prevent the development of intractable epilepsy.
K‐Opioid Agonist Modulation of [3H]Thymidine Incorporation into DNA: Evidence for the Involvement of Pertussis Toxin‐Sensitive G Protein‐Coupled Phosphoinositide Turnover
Authors: Barg Jacob , Belcheva Mariana Mancheva , Rowiński Jan , Coscia Carmine James
Published: October 2006

Abstract: A body of evidence has indicated that μ‐opioid agonists can inhibit DNA synthesis in developing brain. We now report that K‐selective opioid agonists (U69593 and U50488) modulate [3H]thymidine incorporation into DNA in fetal rat brain cell aggregates in a dose‐ and developmental stage‐dependent manner. K agonists decreased thymidine incorporation by 35% in cultures grown for 7 days, and this process was reversed by the K‐selective antagonist, norbinaltorphimine, whereas in 21‐day brain cell aggregates a 3,5‐fold increase was evident. Cell labeling by [3H]thymidine was also inhibited by the K‐opioid agonist as shown by autoradiography. In addition, U69593 reduced basal rates of phosphoinositide formation in 7‐day cultures and elevated it in 21‐day cultures. Control levels were restored by norbin‐altorphimine. Pertussis toxin blocked U69593‐mediated inhibition of DNA synthesis. The action of K agonists on thymidine incorporation in the presence of chelerythrine, a protein kinase C (PKC) inhibitor, or in combination with LiCl, a noncompetitive inhibitor of inositol phosphatase, was attenuated in both 7‐ and 21‐day cultures. These results suggest that K agonists may inhibit DNA synthesis via the phosphoinositide system with a pertussis toxin‐sensitive G protein as transducer. In mixed glial cell aggregates, U50488 increased thymidine incorporation into DNA 3.1‐fold, and this stimulation was reversed by the opioid antagonist naltrexone.
Isolation of a Drosophila Gene Encoding a Head‐Specific Guanylyl Cyclase
Authors: Yoshikawa Shingo , Miyamoto Issei , Aruga Jun , Furuichi Teiichi , Okano Hideyuki , Mikoshiba Katsuhiko
Published: October 2006

Abstract: We have isolated and characterized a new guanylyl cyclase gene (dgcl) in Drosophila. The deduced amino acid sequence (683 amino acids) most closely resembled the mammalian solubletype guanylyl cyclase α subunit. The cyclase catalytic domain was highly conserved between the mammalian and Drosophila guanylyl cyclases. The dgcl mRNA was detected in wild‐type heads but not in bodies, and its level was reduced in the mutant eyes absent (eya), indicating that dgcl is preferentially expressed in the CNS and in the eye. The enriched distribution in the eye suggests that dgcl may have a role in phototransduction.
Binding at an NFI Site Is Modulated by Cyclic AMP–Dependent Activation of Myelin Basic Protein Gene Expression
Authors: Zhang Xiaoping , Miskimins Robin
Published: October 2006

Abstract: Using stable cell lines containing a series of deletions of the myelin basic protein (MBP) promoter directing the bacterial chloramphenicol acetyltransferase gene in a peripheral neurinoma cell line, we have studied the sequences in the MBP promoter needed for induction by cyclic AMP. Stimulation of expression from the MBP promoter by cyclic AMP is not a rapid response. Expression begins after 24 h and reaches a maximum at ˜72 h. The results from the stable transformants indicate at least one region that appears to be essential to the induction of transcription directed by the MBP promoter. The region that is necessary for induction does not contain a consensus cyclic AMP response element. A specific binding site involved in the induction by cyclic AMP was localized to an NFI binding site.
Mobilization of a Vesamicol‐Insensitive Pool of Acetylcholine from a Sympathetic Ganglion by Ouabain
Authors: Prado Marco Antonio M. , Gomez Marcus V. , Collier Brian
Published: October 2006

Abstract: These experiments investigate the release of transmitter from the perfused superior cervical ganglia of cats induced by ouabain in the absence or presence of 2‐(4‐phenylpiperidino)cyclohexanol (vesamicol), a blocker of acetylcholine (ACh) uptake. Ouabain, perfused through the ganglia, released ACh in a Ca2+‐dependent way. Vesamicol caused some inhibition of the release of ACh by ouabain; however, under this condition, the Na+, K+‐ATPase inhibitor released five times more transmitter than did preganglionic stimulation at 5 Hz. Also, when ganglia exposed to vesamicol were depleted of the impulse‐releasable pool of ACh, subsequent perfusion with ouabain released ACh, and this included ACh newly synthesized in the presence of vesamicol; this phenomenon could be inhibited by the lack of Ca2+ and presence of EGTA, and was completely abolished by perfusion with a medium containing 18 mM Mg2+. To test whether the release of this vesamicol‐insensitive Ca2+‐dependent pool by ouabain is associated with a decrease in the number of synaptic vesicles, ganglia treated with the ATPase inhibitor after the depletion of the impulse‐releasable pool of ACh were fixed for electron microscopy. In the presence of Ca2+, coincident with the release of the vesamicol‐insensitive pool of ACh, nerve terminals were almost depleted of synaptic vesicles; ganglia treated similarly, but with medium containing 18 mM Mg2+ instead of Ca2+, were not depleted of synaptic vesicles. These results suggest that ouabain releases a vesamicol‐insensitive pool of ACh from the sympathetic ganglion and also support the notion that this compartment is vesicular and its exocytosis depends on extracellular Ca2+. It is suggested that empty‐vesicle recycling in the presence of vesamicol restricts mobilization of full vesicles to release sites.
Embryonic Development and Postnatal Changes in Free d‐Aspartate and d‐Serine in the Human Prefrontal Cortex
Authors: Hashimoto Atsushi , Kumashiro Shin , Nishikawa Toru , Oka Takae , Takahashi Kiyohisa , Mito Takashi , Takashima Sachio , Doi Nagafumi , Mizutani Yoshihiko , Yamazaki Tatsuji , Kaneko Tsuguo , Ootomo Eiji
Published: October 2006

Abstract: We have analyzed free chiral amino acids (aspartate and serine) in the human frontal cortex at different ontogenic stages (from 14 weeks of gestation to 101 years of age) by HPLC with fluorometric detection after derivatization with N‐tert‐butyl‐oxycarbonyl‐l‐cysteine and o‐phthaldialdehyde. Exceptionally high levels of free d‐aspartate and d‐serine were demonstrated in the fetal cortex at gestational week 14. The ratios of d‐aspartate and of d‐serine to the total corresponding amino acids were also high, at 0.63 and 0.27, respectively. The concentration of d‐aspartate dramatically decreased to a trace level by gestational week 41 and then remained very low during all postnatal stages. In contrast, the frontal tip contained persistently high levels of d‐serine throughout embryonic and postnatal life, whereas the d‐amino acid content in adolescents and aged individuals was about half of that in the fetuses. Because d‐aspartate and d‐serine are known to have selective actions at the NMDA‐type excitatory amino acid receptor, the present data suggest that these d‐amino acids might play a pivotal role in cerebral development and functions that are related to the NMDA receptor.
Aurintricarboxylic Acid Protects Hippocampal Neurons from NMDA‐and Ischemia‐Induced Toxicity In Vivo
Authors: Roberts‐Lewis Jill M. , Marcy Val R. , Zhao Yonghua , Vaught Jeffry L. , Siman Robert , Lewis Michael E.
Published: October 2006

Abstract: The polymeric dye aurintricarboxylic acid (ATA) has been shown to protect various cell types from apoptotic cell death, reportedly through inhibition of a calcium‐dependent endonuclease activity. Recent studies have indicated that there may be some commonalities among apoptosis, programmed cell death, and certain other forms of neuronal death. To begin to explore the possibility of common biochemical mechanisms underlying ischemia‐or excitotoxin‐induced neuronal death and apoptosis in vivo, gerbils or rats subjected to transient global ischemia or NMDA microinjection, respectively, received a simultaneous intracerebral infusion of ATA or vehicle. As a biochemical marker of neuronal death, spectrin proteolysis, which is mediated by activation of calpain I, was measured in hippocampus after 24 h. ATA treatment resulted in a profound reduction of both NMDA‐and ischemia‐induced spectrin proteolysis, consistent with the possibility of some common mechanism in apoptosis and other forms of neuronal death in vivo.
Aurintricarboxylic Acid Protects Hippocampal Neurons from Glutamate Excitotoxicity In Vitro
Authors: Samples Stephen D. , Dubinsky Janet M.
Published: October 2006

Abstract: Aurintricarboxylic acid (ATA), an endonuclease inhibitor, has been shown to protect several cell types from an apoptotic form of cell death. We tested ATA for protective effects against glutamate excitotoxicity in 2‐week‐old cultured hippocampal neurons. Cell viability was determined 24 h after glutamate exposure either by trypan blue exclusion or by measurement of lactate dehydrogenase release. When ATA was added during exposure to glutamate, there was a dramatic increase in the number of viable neurons compared with cultures that did not receive ATA. If ATA was added after glutamate exposure, the rate of survival approached 100%. Several cellular processes may be the targets for ATA action. If the mechanisms of ATA protection are similar for excitotoxicity and apoptosis, then these distinct forms of cell death may share a common intracellular pathway.
Cytochalasin Modulation of Nicotinic Cholinergic Receptor Expression and Muscarinic Receptor Function in Human TE671/RD Cells: A Possible Functional Role of the Cytoskeleton
Authors: Bencherif Merouane , Lukas Ronald J.
Published: October 2006

Abstract: Previous studies have shown that cells of the TE671/RD human clonal line express muscle‐type nicotinic acetylcholine receptors (nAChR) and m3‐type muscarinic acetylcholine receptors (mAChR) whose numbers and function are regulated by agonist treatment and second messenger modulation. Here we show that cytochalasin treatment, which causes disruption of actin networks, induces marked changes in the numbers and distribution of nAChR, but not mAChR. Moreover, whereas cytochalasin treatment fails to alter nAChR function significantly, it acutely potentiates mAChR‐mediated phosphoinositide hydrolysis. Treatment of TE671/RD cells with different cytochalasin analogues (rank order efficacy at 5 μg/ml is H >J = B = C = D>A = E) produces a two‐to fourfold increase in numbers of membrane‐bound nAChR (Smax in units of specific 125l‐labeled α‐bungarotoxin binding per milligram of membrane protein). nAChR up‐regulation is evident after 1–2 days of cytochalasin B exposure, is maximal after 3–6 days of drug treatment, and is dominated by an approximately 10‐fold increase (per cell) in an intracellular nAChR pool. Cytochalasin‐induced nAChR up‐regulation is similar in magnitude to, but not additive with, up‐regulation of nAChR following chronic exposure to nicotine or phorbol ester. Northern blot analysis shows a four‐to fivefold coordinate increase in levels of mRNA that encode nAChR α, β, γ, or θ subunits in cytochalasin‐treated cells, suggesting that nAChR up‐regulation has a possible transcriptional basis. Studies done using a 86Rb+ efflux assay indicate that cytochalasin treatment has no significant effect on nAChR function. By contrast, cytochalasin treatment has no effect on the numbers of mAChR as assessed by binding studies with the radioantagonist 3H‐labeled quinuclidinyl benzilate, but it induces marked enhancement of carbachol‐stimulated, but not basal, phosphoinositide hydrolysis. These studies suggest that presumed modulation by cytochalasin treatment of cytoskeletal microfilament integrity can differentially influence expression and function of mAChR (a prototype of the metabotropic receptor superfamily) and nAChR (a prototype of the ligand‐gated ion‐channel superfamily). The results also suggest possible new roles for the cytoskeleton in regulation of membrane receptor expression, function, and cross talk.
Heterogeneity of the High Molecular Weight τ Proteins in N115 Neuroblastoma Cells
Authors: Gache Y. , Guilleminot J. , Bridoux A. M. , Nunez J.
Published: October 2006

Abstract: The sequence of a high molecular weight (HMW) τ cDNA cloned from a neuroblastoma N115 library contains, in addition to the C‐and N‐terminal and middle regions present in the low molecular weight mouse brain τ proteins, a 711‐bp nonhomologous domain (exon 4a) and a region of 198 bp corresponding to exon 6 of the τ gene. Protein immunoblot analysis, performed with antibodies specific either for a sequence present in the N‐terminal region of all the τ variants or for exon 4a revealed several bands suggesting that more than one τ form is expressed in this cell line. Northern blot experiments performed with a number of cDNA probes spanning domains common and uncommon to low molecular weight and HMW τ allowed the identification of four τ transcripts differing in the size of their coding and noncoding regions. All these transcripts contain the sequence encoded by exon 6, but two of them lack exon 4a. As shown by RNase protection assays, the N‐terminal region of these transcripts is also variable and contains either exon 1, or exons 1 and 2, or exons 1–3. Yet all these HMW τ forms contain four homologous repeats in their C‐terminal domain both in the differentiated and nondifferentiated cells, i.e., have adult characteristics. In conclusion, the data reported in this article demonstrate that several HMW τ variants are expressed in neuroblastoma N115 cells and that the transition between immature to mature τ forms occurring during brain development is not required for neurite outgrowth during morphological differentiation of this cell line.
Effect of an n‐3 Fatty Acid‐Deficient Diet on the Adenosine‐Dependent Melatonin Release in Cultured Rat Pineal
Authors: Gazzah N. , Gharib A. , Delton I. , Molière P. , Durand G. , Christen R. , Lagarde M. , Sarda N.
Published: October 2006

Abstract: We studied the effect of a diet deficient in n‐3 fatty acids on the adenosine‐dependent melatonin release from cultured rat pineal gland after stimulation by 5′‐N‐ethylcarboxamidoadenosine (NECA), an A2 adenosine agonist. Experiments were conducted with 2‐month‐old rats raised on semipurified diets containing either peanut oil (n‐3 deficients) or peanut plus rapeseed oil (controls). The proportion of docosahexaenoic acid (22:6 n‐3) in the pineal total lipid fraction and in phosphatidylcholine and phosphatidylethanolamine was significantly decreased in n‐3‐deficient rats. This was compensated for partially by an increase in 22:4 n‐6 and 22:5 n‐6 levels. The activity of the cultured rat pineal, in terms of cyclic AMP content and N‐acetylserotonin and melatonin release in the medium, was lower after stimulation by 10‐5 mol/L NECA in the group fed peanut oil than in the group fed peanut plus rapeseed oil. The increased ratio of n‐6/n‐3 fatty acids in pineal total lipids and the major glycerophospholipids (phosphatidylcholine and phosphatidylethanolamine) may have an important influence on the rat pineal responses. The results are discussed in the context of changes in membrane‐bound proteins, including enzymes and/or receptors involved in the rat pineal gland function.
Chronic Dopamine D2 Receptor Activation Does Not Affect Survival and Differentiation of Cultured Dopaminergic Neurons: Morphological and Neurochemical Observations
Authors: Van Muiswinkel F. L. , Drukarch B. , Steinbusch H. W. M. , Stoof J. C.
Published: October 2006

Abstract: Primary cultures of rat ventral mesencephalon were used to elucidate the role of chronic stimulation of dopamine (DA) D2 autoreceptors in the development of fetal dopaminergic neurons in vitro. Cultured dopaminergic neurons, as visualized by tyrosine hydroxylase immunocytochemistry, became more differentiated in the course of cultivation time and exhibited specific high‐affinity uptake for [3H]DA. In rat striatal tissue, activation of D2 receptors has been shown to inhibit the release of DA. Previously accumulated [3H]DA was released from the cultures upon depolarization in a Ca2+‐dependent manner. K+‐evoked [3H]DA release could be inhibited by the selective D2 receptor agonists LY 171555 and N0437 in a concentration‐dependent manner. The inhibitory effects of LY 171555 and N0437 were antagonized by the selective DA D2 receptor antagonist sulpiride. These observations are indicative for the expression of functional D2 receptors in the cultures. Daily treatment of these cultures for 7 days with LY 171555 or sulpiride did not lead to any change in protein content, the number of tyrosine hydroxylase‐immunoreactive neurons, or the uptake capacity for [3H]DA. Our data demonstrate that chronic stimulation of DA D2 receptors does not impair survival or differentiation of cultured fetal dopaminergic neurons.
Plasticity of Astroglial Glutamate and γ‐Aminobutyric Acid Uptake in Cell Cultures Derived from Postnatal Mouse Cerebellum
Authors: Voisin Pierre , Viratelle Odile , Girault Jeanne‐Marie , Morrison‐Bogorad Marcelle , Labouesse Julie
Published: October 2006

Abstract: The plasticity of astroglial glutamate and γ‐aminobutyric acid (GABA) uptakes was investigated using mouse cerebellar cell cultures. The influence of external factors, such as different sera and/or the presence of neurons, was examined. Control autoradiography experiments showed that after short‐term exposure to radioactive amino acids, granule cells took up neither glutamate nor GABA, and β‐alanine predominantly inhibited astroglial GABA uptake. Astroglial uptake was quantified by measuring the radioactivity taken up by the cells in the culture and relating this measurement to the number of glial fibrillary acidic protein‐positive cells present. Glutamate uptake was investigated in astroglial cultures and subcultures and in neuro‐nal‐astroglial cultures derived from postnatal day 4 mouse cerebella. In the absence of neurons, glutamate uptake increased during the first 9 days after plating and then leveled off. At 14 days in vitro in horse serum, which favors the differentiation of fibrous‐like astrocytes, glutamate uptake related to astrocyte number was twice as high as in fetal calf serum. In the presence of cerebellar neurons, this rate was even higher. The specificity of the responsiveness of astrocytes to neurons with respect to glutamate uptake was investigated by comparing GABA uptake in the different culture conditions. Neurons also increased the rate of GABA uptake by astrocytes. Another component of the astroglial plasma membrane, the density of β‐adrenergic receptors, was, however, not markedly affected by the presence of neurons. Hence, these results showed that in astrocytes plated from postnatal day 4 mouse cerebella, the level of neuro‐transmitter uptake can be regulated in vitro by factors present in sera and by cerebellar neurons in the culture. However, this plasticity declined during development because astrocytes plated from postnatal day 8 cerebella and cultured under identical conditions were less active in glutamate uptake and were insensitive to the presence of horse serum. The latter observation suggested that the metabolic plasticity of astrocytes is restricted to a period defined early in cerebellar development and is no longer evident by postnatal day 8.
Synergistic Interaction of Muscarinic and Opioid Receptors with Gs‐Linked Neurotransmitter Receptors to Stimulate Adenylyl Cyclase Activity of Rat Olfactory Bulb
Authors: Olianas Maria C. , Onali Pierluigi
Published: October 2006

We reported previously that in homogenates of rat olfactory bulb muscarinic and opioid receptor agonists stimulate adenylyl cyclase activity. In the present study we show that carbachol (CCh) and Leu‐Enkephalin act synergistically with vasoactive intestinal peptide (VIP) and corticotropin‐releasing hormone (CRH), but not with /‐isoproterenol, in increasing cyclic AMP formation. The synergistic interaction consists of an increase in the maximal a0denylyl cyclase activation without a significant change in the potency of each agonist. CCh also fails to affect 125ICRH binding to olfactory bulb membranes. The synergism requires micromolar concentrations of GTP. Substitution of the stable GTP analog guanosine 5′‐O‐(3′‐thiotriphosphate) for GTP allows the CRH stimulation, but abolishes the CCh enhancement of both basal and CRH‐stimulated enzyme activities. Moreover, in vivo treatment of olfactory bulbs with pertussis toxin completely prevents the muscarinic and opioid effects. Thus, the synergistic interaction appears to result from opioid‐ and muscarinic‐induced activation of a pertussis toxin‐sensitive GTP‐binding protein which may potentiate the adenylyl cyclase stimulation by the stimulatory GTP‐binding protein activated by either VIP or CRH receptors.
A Review of Children's, Teachers' and Parents' Influences on Children's Drawing Experience
Authors: Rose Sarah E. , Jolley Richard P. , Burkitt Esther
Published: October 2006

In this article we argue that research into children's drawings should consider the context in which drawing occurs and that it is crucial to investigate the attitudes and practices of teachers, parents and children themselves that shape children's drawing experience and the drawings which they produce. We review the findings of seven empirical studies reporting data collected through direct observations, interviews and questionnaires from the three main players (teachers, parents and children) on the attitudes and practices shaping children's drawing. Issues covered include teachers' perceptions of the purposes and importance of drawing, support offered by teachers, parents and children for children's drawing endeavours, and possible factors that may lead to an age‐related decline in the amount of drawing children choose to do.

We end the review by reporting some preliminary findings from our own large‐scale interview and survey study of 270 5–14 year old children, their parents and teachers, that provides a comprehensive assessment of attitudes and practices influencing children's drawing experience at home and at school. The findings provide further insight into the aforementioned issues, particularly children's, teachers' and parent's explanations of why children's drawing behaviour might decline with age. It is hoped that by reporting these preliminary findings some additional understanding of the context in which children produce their drawings can be gained and new areas for debate opened up.
Role of anticyclic citrullinated peptide 2 assay in long‐standing rheumatoid arthritis
Authors: NG Kristine P. , AUSTIN Paul , AMERATUNGA Rohan , McQUEEN Fiona
Published: October 2006

Background:  The anti‐cyclic citrullinated peptide (anti‐CCP) antibody test is a new serological marker with high specificity for rheumatoid arthritis (RA).

Aims:  This study evaluated the frequency of anti‐CCP antibodies in comparison to rheumatoid factor (RF) in a group of patients with inflammatory polyarthritis.

Methods:  Samples were obtained from 106 patients with established RA and non‐RA inflammatory polyarthritis. Anti‐CCP (second generation assay – INOVA) and RF antibodies were measured by enzyme‐linked immunosorbent assay. Patient demographics, disease duration and clinical diagnosis were obtained.

Results:  Fifty‐five patients had established RA and the remaining 51 had non‐RA inflammatory polyarthritis. The sensitivity of the anti‐CCP2 assay for a diagnosis of RA was 73% compared with 56% for RF. In the RA group, half the RF negative patients (12/24) tested positive for anti‐CCP. The specificity of anti‐CCP was extremely high at 98% compared with RF at 94%. In the non‐RA group, only one patient with lupus tested positive for anti‐CCP compared with three who were RF positive (all of whom also had lupus).

Conclusion:  The second generation anti‐CCP assay was more sensitive and specific than RF for a diagnosis of RA in this population. This test may improve accuracy of diagnosis in patients with long‐standing polyarthritis.
Profile of opportunistic infections among patients on immunosuppressive medication
Authors: REDDY Srinivas , WANCHU Ajay , GUPTA Vaishali , BAMBERY Pradeep
Published: October 2006

Background:  The widespread use of immunosuppressives in treating systemic autoimmune disorders has resulted in opportunistic infections (OIs) following such therapy. Current data regarding the possibility of infection due to these drugs or from the primary disease, per se, is conflicting.

Objectives:  We aimed to analyse the profile of patients requiring hospitalization for OIs among those being treated with glucocorticoids and other immunosuppressive agents as part of management of systemic autoimmune disorders and to analyse the host factors in relation to OIs.

Method:  In this descriptive analysis, all patients hospitalized the Postgraduate Institute of Medical Education and Research, Chandigarh, India, under medicinal units for OIs that occurred following and during treatment with corticosteroids and other immunosuppressive agents for treatment of systemic autoimmune disorders from February 2002 to January 2003, were studied. All hospitalized patients received antibiotics according to the nature of infection and sensitivity reports. All relevant clinical details were recorded in a standard pro forma. Descriptive statistics were used. The Institute Ethics Committee's permission was secured prior to study commencement.

Results:  Nineteen patients (16 female) were admitted because of OIs. Their mean age (± SD) was 37.32 (± 19.9) years. Ten patients had systemic lupus erythematosus (SLE), two had SLE with overlap, five had rheumatoid arthritis, and one each had vasculitis and scleroderma with polymyositis. There were 28 infections. One (5.3%) patient had four infections, one (5.3%) had three, six (31.6%) had two, nine (47.4%) had one, and in two (10.5%) patients the infection was not localized. Of the 19 cases, 10 (52.6%) received > 10 mg of prednisolone each day (median = 1130 mg). The remaining nine (47.4%) were on < 10 mg prednisolone each day (median = 880 mg). Methylprednisolone was given to two (6.3%) patients. Bacteria accounted for most of the infections. There were two fungal infections and one patient each with tuberculosis and peritonitis. Infections occurred predominantly in the chest, urine and skin. Septicemia was diagnosed in three patients. There were two deaths, one each with SLE and rheumatoid arthritis.

Conclusion:  Since infections can occur at low doses of corticosteroids, we suggest that these disorders may be, per se, responsible for an increased risk of infection.
A refractory case of dermatomyositis complicated with multiple brain abscesses
Authors: MARUOKA Hiroshi , KOGA Takeharu , JINNNOUCHI Yoshikazu , HONDA Seiyo , TAKEO Masaaki , YUGE Kentaro , FUKUDA Takaaki , AIZAWA Hisamichi
Published: October 2006

We describe a 48‐year‐old woman with dermatomyositis complicated with interstitial pneumonia. The pulmonary lesion was refractory; however, several therapeutic regimens such as steriod pulse therapy or gamma globulin and cyclophosphamide, resolved the situation. Later she developed multiple brain abscesses thought to be responsible for immune depression; prolonged antimycotic therapy brought dramatic improvement. Brain abscess is a rare complication in such immuno‐compromised cases; attention should be given to the possibility of deep mycosis, especially brain abscess.
Intravenous pamidronate in the treatment of sternoclavicular hyperostosis
Authors: LU T. Y.‐T. , KWIATEK R. , LIMAYE Vidya
Published: October 2006

The SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis and osteitis) is a rare clinical entity in which osteosclerosis and osteolysis are consistent radiological findings. We present a patient with SAPHO syndrome manifesting as painful sternoclavicular hyperostosis treated successfully with pamidronate. For the first time, a reduction in isotope bone scan activity was documented in parallel to a favourable clinical response. Bisphosphonates have potent antiosteoclastic and anti‐inflammatory effects. By virtue of their dual effects on bone remodelling and inflammation, they seem an appropriate therapy in the management of SAPHO syndrome. This case demonstrates the efficacy of pamidronate, both clinically and radiologically, as first line therapy for patients with isolated hyperostosis.
Resolution of skin fibrosis and joint contractures in aggressive diffuse systemic sclerosis using autologous stem cell transplantation
Authors: ANANDACOOMARASAMY Ananthila , MOORE John , MCGILL Neil , MANOLIOS Nicholas , ENGLERT Helen
Published: October 2006

The use of haematopoietic stem cell transplantation (HSCT) has now expanded beyond the domain of haematological diseases. Increasingly, the benefits of intense immunosuppression in the management of severe autoimmune diseases are being recognized. In diffuse systemic sclerosis (SSc), there has been increasing evidence of the efficacy of HSCT in improving morbidity and mortality. We present the first Australian patient to undergo autologous HSCT for SSc and review the current literature in the use of HSCT in SSc. Remarkably, the patient had complete resolution of skin disease (modified Rodnan skin score 27/51–0/51), tenosynovitis, synovitis and myositis.
Hereditary sensory neuropathy type I
Authors: OWLIA M. B. , SOLEIMANI H. , HADDAD H. R. , DAVATCHI F.
Published: October 2006

Hereditary sensory neuropathy type I (HSN‐I) is a rare genetic disorder that usually begins in childhood, predominantly affecting the peripheral nerves of the lower limbs, and occasionally also those of the upper extremities. Foot deformities such as pes cavus, pes planus, sensory loss, painless injuries or burns, recurrent foot ulceration resulting in osteonecrosis and osteolysis subsequently necessitate amputations. Herein, we describe a 45‐year‐old man with progressive foot ulceration and self‐amputation during previous 20 years. The diagnosis of HSN was made because of a typical clinical pattern and similar occurrence in his brother. Laboratory investigations showed peripheral sensory neuropathy and a high erythrocyte sedimentation rate.
Poly(ether imide) Scaffolds as Multifunctional Materials for Potential Applications in Regenerative Medicine
Authors: Lützow Karola , Weigel Thomas , Lendlein Andreas
Published: October 2006

Abstract:  This article gives an overview of scaffolds that can be prepared from poly(ether imide) (PEI). These scaffolds were developed for extracorporeal blood detoxification processes in which specific compounds from blood or plasma are removed selectively. Both the preparation of porous microparticles and the preparation of hollow fibers are described. Commercially available particulate support materials have the disadvantage of a low accessibility of the internal pore system, a poor flow‐through behavior and low adsorption specificity. Thus, novel support materials with optimally adapted properties profiles are needed. The second part of this article shows some recently developed highly asymmetric PEI hollow fibers. PEI scaffolds can be considered multifunctional because they combine separation characteristics, biocompatibility, sufficient biostability, and the possibility of creating tailor‐made biofunctional surfaces.
Prevalence of Perceived Dysphonia in a Geriatric Population
Authors: Golub Justin S. , Chen Po‐Hung , Otto Kristen J. , Hapner Edie , Johns Michael M.
Published: October 2006

OBJECTIVES: To characterize geriatric dysphonia, including its prevalence, quality‐of‐life impairment, and association with overall health status.

DESIGN: A validated survey‐based study of geriatric dysphonia.

SETTING: An independent living facility for geriatric individuals.

PARTICIPANTS: The entire population of residents at the facility was offered the survey. The inclusion criterion was aged 65 and older.

MEASUREMENTS: Two survey‐based measures were used to characterize dysphonia: a direct question asking whether participants had problems with their voice and a voice‐related quality‐of‐life (V‐RQOL) measure. In addition, participants were administered the 12‐item Medical Outcomes Study Short Form survey, U.S. version 2.0, a concise survey designed to evaluate overall health status.

RESULTS: The prevalence of dysphonia was 20%. More than 50% of patients with voice problems incurred significant quality‐of‐life impairment resulting from their dysphonia as measured using V‐RQOL scores. The mean total V‐RQOL score±standard deviation was 89±20. Finally, general health measures did not reflect V‐RQOL.

CONCLUSION: There is a high prevalence of voice problems in older people, with a large proportion having significantly impaired quality of life related to their dysphonia. General health measures do not reflect V‐RQOL, and many individuals may wrongly attribute dysphonia to age‐related change alone. Administration of validated instruments for assessing dysphonia is encouraged, because direct questions regarding voice difficulties may not be sensitive to the severity of vocal impairment.