bluuebunny/crossref_metadata_2025 huggingface dataset:
A cell‐biological model of p75NTR signaling
Authors: Blöchl A. , Blöchl R.
Published: May 2007

Neurotrophin stimulation of tropomyosin‐related kinase (Trk) and p75 receptors influences cellular processes such as proliferation, growth, differentiation, and other cell‐specific functions, as well as regeneration. In contrast to Trk receptors, which have a well‐defined trophic role, p75 has activities ranging from trophism to apoptosis. Continued neurotrophin stimulation of differentiating neurons transforms the initially trophic character of p75 signaling into negative growth control and overstimulation leads to apoptosis. This function shift reflects the signaling effects of ceramide that is generated upon stimulation of p75. The use of ceramide signaling by p75 may provide a key to understanding the cell‐biological role of p75. The review presents arguments that the control of cell shape formation and cell selection can serve as an organizing principle of p75 signaling. Concurrent stimulation by neurotrophins of p75 and Trk receptors constitutes a dual growth control with antagonistic and synergistic elements aimed at optimal morphological and functional integration of cells and cell populations into their context.
Brain energy metabolism and neurotransmission at near‐freezing temperatures: in vivo1H MRS study of a hibernating mammal
Authors: Henry Pierre‐Gilles , Russeth Kevin P. , Tkac Ivan , Drewes Lester R. , Andrews Matthew T. , Gruetter Rolf
Published: May 2007

The brain of a hibernating mammal withstands physiological extremes that would result in cerebral damage and death in a non‐hibernating species such as humans. To examine the possibility that this neuroprotection results from alterations in cerebral metabolism, we used in vivo1H NMR spectroscopy at high field (9.4 T) to measure the concentration of 18 metabolites (neurochemical profile) in the brain of 13‐lined ground squirrels (Spermophilus tridecemlineatus) before, during, and after hibernation. Resolved in vivo1H NMR spectra were obtained even at low temperature in torpid hibernators (∼7°C). The phosphocreatine‐to‐creatine ratio was increased during torpor (+143%) indicating energy storage, and remained increased to a lesser extent during interbout arousal (IBA) (+83%). The total γ‐aminobutyric acid concentration was increased during torpor (+135%) and quickly returned to baseline during IBA. Glutamine (Gln) was decreased (−54%) during torpor but quickly returned to normal levels during IBA and after terminal arousal in the spring. Glutamate (Glu) was also decreased during torpor (−17%), but remained decreased during IBA (−20% compared with fall), and returned to normal level in the spring. Our observation that Glu and Gln levels are depressed in the brain of hibernators suggests that the balance between anaplerosis and loss of Glu and Gln (because of glutamatergic neurotransmission or other mechanisms) is altered in hibernation.
‘Mild Uncoupling’ does not decrease mitochondrial superoxide levels in cultured cerebellar granule neurons but decreases spare respiratory capacity and increases toxicity to glutamate and oxidative stress
Authors: Johnson‐Cadwell L. I. , Jekabsons M. B. , Wang A. , Polster B. M. , Nicholls D. G.
Published: May 2007

Cultured rat cerebellar granule neurons were incubated with low nanomolar concentrations of the protonophore carbonylcyanide‐p‐trifluoromethoxyphenyl hydrazone (FCCP) to test the hypothesis that ‘mild uncoupling’ could be neuroprotective by decreasing oxidative stress. To quantify the uncoupling, respiration and mitochondrial membrane potential (Δψm) were determined in parallel as a function of FCCP concentration. Δψm dropped by less than 10 mV before respiratory control was lost. Conditions for the valid estimation of matrix superoxide levels were determined from the rate of oxidation of the matrix‐targeted fluorescent probe MitoSOX. No significant change in the level of matrix superoxide could be detected on addition of FCCP while respiratory control was retained, although cytoplasmic superoxide levels measured by dihydroethidium oxidation increased. ‘Mild uncoupling’ by 30 nmol/L FCCP did not alleviate neuronal dysregulation induced by glutathione depletion and significantly enhanced that due to menadione‐induced oxidative stress. Low protonophore concentrations enhanced N‐methyl‐d‐aspartate receptor‐induced delayed calcium deregulation consistent with a decrease in the spare respiratory capacity available to match the bioenergetic demand of chronic receptor activation. It is concluded that the ‘mild uncoupling’ hypothesis is not supported by this model.
Identification, physiological actions, and distribution of TPSGFLGMRamide: a novel tachykinin‐related peptide from the midgut and stomatogastric nervous system of Cancer crabs
Authors: Stemmler Elizabeth A. , Peguero Braulio , Bruns Emily A. , Dickinson Patsy S. , Christie Andrew E.
Published: May 2007

In most invertebrates, multiple species‐specific isoforms of tachykinin‐related peptide (TRP) are common. In contrast, only a single conserved TRP isoform, APSGFLGMRamide, has been documented in decapod crustaceans, leading to the hypothesis that it is the sole TRP present in this arthropod order. Previous studies of crustacean TRPs have focused on neuronal tissue, but the recent demonstration of TRPs in midgut epithelial cells in Cancer species led us to question whether other TRPs are present in the gut, as is the case in insects. Using direct tissue matrix assisted laser desorption/ionization Fourier transform mass spectrometry, in combination with sustained off‐resonance irradiation collision‐induced dissociation, we found that at least one additional TRP is present in Cancer irroratus, Cancer borealis, Cancer magister, and Cancer productus. The novel TRP isoform, TPSGFLGMRamide, was present not only in the midgut, but also in the stomatogastric nervous system (STNS). In addition, we identified an unprocessed TRP precursor APSGFLGMRG, which was detected in midgut tissues only. TRP immunohistochemistry, in combination with preadsorption studies, suggests that APSGFLGMRamide and TPSGFLGMRamide are co‐localized in the stomatogastric ganglion (STG), which is contained within the STNS. Exogenous application of TPSGFLGMRamide to the STG elicited a pyloric motor pattern that was identical to that elicited by APSGFLGMRamide, whereas APSGFLGMRG did not alter the pyloric motor pattern.
Caffeic acid phenethyl ester reduces neurovascular inflammation and protects rat brain following transient focal cerebral ischemia
Authors: Khan Mushfiquddin , Elango Chinnasamy , Ansari Mubeen A. , Singh Inderjit , Singh Avtar K.
Published: May 2007

Ischemic stroke is a neurovascular disease treatable by thrombolytic therapy, but the therapy has to be initiated within 3 h of the incident. This therapeutic limitation stems from the secondary injury which results mainly from oxidative stress and inflammation. A potent antioxidant/anti‐inflammatory agent, caffeic acid phenethyl ester (CAPE) has potential to mitigate stroke’s secondary injury, and thereby widening the therapeutic window. We observed that CAPE protected the brain in a dose‐dependent manner (1–10 mg/kg body weight) and showed a wide therapeutic window (about 18 h) in a rat model of transient focal cerebral ischemia and reperfusion. The treatment also increased nitric oxide and glutathione levels, decreased lipid peroxidation and nitrotyrosine levels, and enhanced cerebral blood flow. CAPE down‐regulated inflammation by blocking nuclear factor kappa B activity. The affected mediators included adhesion molecules (intercellular adhesion molecule‐1 and E‐selectin), cytokines (tumor necrosis factor‐α and interleukin‐1β) and inducible nitric oxide synthase. Anti‐inflammatory action of CAPE was further documented through reduction of ED1 (marker of activated macrophage/microglia) expression. The treatment inhibited apoptotic cell death by down‐regulating caspase 3 and up‐regulating anti‐apoptotic protein Bcl‐xL. Conclusively, CAPE is a promising drug candidate for ischemic stroke treatment due to its inhibition of oxidative stress and inflammation, and its clinically relevant wide therapeutic window.
Mitochondrial aspartate aminotransferase: a third kynurenate‐producing enzyme in the mammalian brain
Authors: Guidetti Paolo , Amori Laura , Sapko Michael T. , Okuno Etsuo , Schwarcz Robert
Published: May 2007

The tryptophan metabolite kynurenic acid (KYNA), which is produced enzymatically by the irreversible transamination of l‐kynurenine, is an antagonist of α7 nicotinic and NMDA receptors and may thus modulate cholinergic and glutamatergic neurotransmission. Two kynurenine aminotransferases (KAT I and II) are currently considered the major biosynthetic enzymes of KYNA in the brain. In this study, we report the existence of a third enzyme displaying KAT activity in the mammalian brain. The novel KAT had a pH optimum of 8.0 and a low capacity to transaminate glutamine or α‐aminoadipate (the classic substrates of KAT I and KAT II, respectively). The enzyme was inhibited by aspartate, glutamate, and quisqualate but was insensitive to blockade by glutamine or anti‐KAT II antibodies. After purification to homogeneity, the protein was sequenced and the enzyme was identified as mitochondrial aspartate aminotransferase (mitAAT). Finally, the relative contributions of KAT I, KAT II, and mitAAT to total KAT activity were determined in mouse, rat, and human brain at physiological pH using anti‐mitAAT antibodies. KAT II was most abundant in rat and human brain, while mitAAT played the major role in mouse brain. It remains to be seen if mitAAT participates in cerebral KYNA synthesis under physiological and/or pathological conditions in vivo.
Involvement of KCNQ2 subunits in [3H]dopamine release triggered by depolarization and pre‐synaptic muscarinic receptor activation from rat striatal synaptosomes
Authors: Martire Maria , D’Amico Monia , Panza Elisabetta , Miceli Francesco , Viggiano Davide , Lavergata Francesco , Iannotti Fabio Arturo , Barrese Vincenzo , Preziosi Paolo , Annunziato Lucio , Taglialatela Maurizio
Published: May 2007

KCNQ2 and KCNQ3 subunits encode for the muscarinic‐regulated current (IKM), a sub‐threshold voltage‐dependent K+current regulating neuronal excitability. In this study, we have investigated the involvement of IKMin dopamine (DA) release from rat striatal synaptosomes evoked by elevated extracellular K+concentrations ([K+]e) and by muscarinic receptor activation. [3H]dopamine ([3H]DA) release triggered by 9 mmol/L [K+]ewas inhibited by the IKMactivator retigabine (0.01–30 μmol/L;Emax = 54.80 ± 3.85%; IC50 = 0.50 ± 0.36 μmol/L). The IKMblockers tetraethylammonium (0.1–3 mmol/L) and XE‐991 (0.1–30 μmol/L) enhanced K+‐evoked [3H]DA release and prevented retigabine‐induced inhibition of depolarization‐evoked [3H]DA release. Retigabine‐induced inhibition of K+‐evoked [3H]DA release was also abolished by synaptosomal entrapment of blocking anti‐KCNQ2 polyclonal antibodies, an effect prevented by antibody pre‐absorption with the KCNQ2 immunizing peptide. Furthermore, the cholinergic agonist oxotremorine (OXO) (1–300 μmol/L) potentiated 9 mmol/L [K+]e‐evoked [3H]DA release (Emax = 155 ± 9.50%; EC50 = 25 ± 1.80 μmol/L). OXO (100 μmol/L)‐induced [3H]DA release enhancement was competitively inhibited by pirenzepine (1–10 nmol/L) and abolished by the M3‐preferring antagonist 4‐diphenylacetoxyN‐methylpiperidine methiodide (1 μmol/L), but was unaffected by the M1‐selective antagonist MT‐7 (10–100 nmol/L) or by Pertussis toxin (1.5–3 μg/mL), which uncouples M2‐ and M4‐mediated responses. Finally, OXO‐induced potentiation of depolarization‐induced [3H]DA release was not additive to that produced by XE‐991 (10 μmol/L), was unaffected by retigabine (10 μmol/L), and was abolished by synaptosomal entrapment of anti‐KCNQ2 antibodies. Collectively, these findings indicate that, in rat striatal nerve endings, IKMchannels containing KCNQ2 subunits regulate depolarization‐induced DA release and that IKMsuppression is involved in the reinforcement of depolarization‐induced DA release triggered by the activation of pre‐synaptic muscarinic heteroreceptors.
Excitotoxicity‐related endocytosis in cortical neurons
Authors: Vaslin A. , Puyal J. , Borsello T. , Clarke P. G. H.
Published: May 2007

Recent studies showed that endocytosis is enhanced in neurons exposed to an excitototoxic stimulus. We here confirm and analyze this new phenomenon using dissociated cortical neuronal cultures. NMDA‐induced uptake (FITC‐dextran or FITC or horseradish peroxidase) occurs in these cultures and is due to endocytosis, not to cell entry through damaged membranes; it requires an excitotoxic dose of NMDA and is dependent on extracellular calcium, but occurs early, while the neuron is still intact and viable. It involves two components, NMDA‐induced and constitutive, with different characteristics. Neither component involves specific binding of the endocytosed molecules to a saturable receptor. Strikingly, molecules internalized by the NMDA‐induced component are targeted to neuronal nuclei. This component, but not the constitutive one, is blocked by a c‐Jun N‐terminal protein kinase inhibitor. In conclusion, an excitotoxic dose of NMDA triggers c‐Jun N‐terminal protein kinase‐dependent endocytosis in cortical neuronal cultures, providing an in vitro model of the excitotoxicity‐induced endocytosis reported in intact tissues.
Transcriptome analysis reveals altered cholesterol metabolism during the neurodegeneration in mouse scrapie model
Authors: Xiang Wei , Hummel Manuela , Mitteregger Gerda , Pace Claudia , Windl Otto , Mansmann Ulrich , Kretzschmar Hans A.
Published: May 2007

To identify the dynamic transcriptional alterations in CNS during the development of prion disease, brains of scrapie‐infected mice and age‐matched, mock‐inoculated controls were analyzed immediately before inoculation and at different time points post‐inoculation using Affymetrix microarray technique. A total of 449 probe sets, representing 430 genes, showed differential expression between scrapie‐ and mock‐inoculated mice over the time course. These genes could be separated into two clusters according to expression patterns: the genes in cluster 1 demonstrated lower mRNA levels in scrapie‐infected brains when compared with mock‐inoculated brains, whereas genes in cluster 2 showed higher mRNA levels in scrapie‐infected brains. Functional analysis of differentially expressed genes revealed the most severely affected biological process: cholesterol metabolism. The expression patterns of the cholesterol‐related genes indicated an inhibited cholesterol synthesis in the diseased brains. Conspicuously, a number of cluster 1 genes, including some of cholesterol‐related genes, showed not only decreasing mRNA levels in scrapie‐infected brains but also increasing mRNA levels in mock‐inoculated brains with increasing age. Quantitative RT‐PCR analysis of some cholesterol‐related genes in untreated mice suggested that changes of the examined genes observed in mock‐inoculated brains are mainly age related. This finding indicated a link between age‐related genes and scrapie‐associated neurodegeneration.
Blood–brain barrier disruption induces in vivo degeneration of nigral dopaminergic neurons
Authors: Rite Inmaculada , Machado Alberto , Cano Josefina , Venero José L.
Published: May 2007

We have evaluated the possibility that changes in the vascular system may constitute a contributing factor for the death of nigral dopaminergic neurons in Parkinson’s disease. Thus, we have employed intranigral injections of vascular endothelial growth factor (VEGF), the most potent inducer of blood–brain barrier (BBB) permeability. A single dose of 1 μg of VEGF, chosen from a dose‐response study, highly disrupted the BBB in the ventral mesencephalon in a time‐dependent manner. A strong regional correlation between BBB disruption and loss of tyrosine hydroxylase‐positive neurons was evident. Moreover, Fluoro‐Jade B labelling showed the presence of dying neurons in the substantia nigra in response to VEGF injection. High number of TUNEL‐positive nuclei was observed in this area along with activation of caspase 3 within nigral dopaminergic neurons. Analysis of the glial population demonstrated a strong inflammatory response and activation of astroglia in response to BBB disruption. We conclude that disruption of the BBB may be a causative factor for degeneration of nigral dopaminergic neurons.
Activation of recombinant human TRPV1 receptors expressed in SH‐SY5Y human neuroblastoma cells increases [Ca2+]i, initiates neurotransmitter release and promotes delayed cell death
Authors: Lam Patricia M. W. , Hainsworth Atticus H. , Smith Graham D. , Owen Davina E. , Davies James , Lambert David G.
Published: May 2007

The transient receptor potential (TRP) vanilloid receptor subtype 1 (TRPV1) is a ligand‐gated, Ca2+‐permeable ion channel in the TRP superfamily of channels. We report the establishment of the first neuronal model expressing recombinant human TRPV1 (SH‐SY5YhTRPV1). SH‐SY5Y human neuroblastoma cells were stably transfected with hTRPV1 using the Amaxa Biosystem (hTRPV1 in pIREShyg2 with hygromycin selection). Capsaicin, olvanil, resiniferatoxin and the endocannabinoid anandamide increased [Ca2+]iwith potency (EC50) values of 2.9 nmol/L, 34.7 nmol/L, 0.9 nmol/L and 4.6 μmol/L, respectively. The putative endovanilloidN‐arachidonoyl‐dopamine increased [Ca2+]ibut this response did not reach a maximum. Capsaicin, anandamide, resiniferatoxin and olvanil mediated increases in [Ca2+]iwere inhibited by the TRPV1 antagonists capsazepine and iodo‐resiniferatoxin with potencies (KB) of ∼70 nmol/L and 2 nmol/L, respectively. Capsaicin stimulated the release of pre‐labelled [3H]noradrenaline from monolayers of SH‐SY5YhTRPV1cells with an EC50of 0.6 nmol/L indicating amplification between [Ca2+]iand release. In a perfusion system, we simultaneously measured [3H]noradrenaline release and [Ca2+]iand observed that increased [Ca2+]ipreceded transmitter release. Capsaicin treatment also produced a cytotoxic response (EC50155 nmol/L) that was antagonist‐sensitive and mirrored the [Ca2+]Iresponse. This model displays pharmacology consistent with TRPV1 heterologously expressed in standard non‐neuronal cells and native neuronal cultures. The advantage of SH‐SY5YhTRPV1is the ability of hTRPV1 to couple to neuronal biochemical machinery and produce large quantities of cells.
Down‐regulation of GRK2 after oxygen and glucose deprivation in rat hippocampal slices: role of the PI3‐kinase pathway
Authors: Lombardi Maria Stella , Vroon Anne , Sodaar Peter , Van Muiswinkel Freek L. , Heijnen Cobi J. , Kavelaars Annemieke
Published: May 2007

G protein‐coupled receptor kinase 2 (GRK2) modulates G protein‐coupled receptor desensitization and signaling. We previously described down‐regulation of GRK2 expression in vivo in rat neonatal brain following hypoxia‐ischemia. In this study, we investigated the molecular mechanisms involved in GRK2 down‐regulation, using organotypic cultures of neonatal rat hippocampal slices exposed to oxygen and glucose deprivation (OGD). We observed a 40% decrease in GRK2 expression 4 h post‐OGD. No changes in GRK2 protein occurred after exposure of hippocampal slices to glucose deprivation only. No significant alterations in GRK2 mRNA expression were detected, suggesting a post‐transcriptional effect of OGD on GRK2 expression. Blockade of the proteasome pathway by MG132 prevented OGD‐induced decrease of GRK2. It has been shown that extracellular signal‐regulated kinase‐dependent phosphorylation of GRK2 at Ser670 triggers its turnover via the proteasome pathway. However, despite a significant increase of pSer670‐GRK2 after OGD, inhibition of the extracellular signal‐regulated kinase pathway by PD98059 did neither prevent the hypoxia‐ischemia‐induced increase in pSer670‐GRK2 nor the down‐regulation of GRK2 protein. Interestingly, inhibition of phosphoinositide‐3‐kinase with wortmannin inhibits both OGD‐induced phosphorylation of GRK2 on Ser670 and the GRK2 decrease. In conclusion, OGD‐induced phosphoinositide‐3‐kinase‐dependent phosphorylation of GRK2 on Ser670 is a novel mechanism leading to down‐regulation of GRK2 protein via a proteasome‐dependent pathway.
Modulation of hippocampal calcium signalling and plasticity by serine/threonine protein phosphatases
Authors: Koss David J. , Hindley Kathleen P. , Riedel Gernot , Platt Bettina
Published: May 2007

Kinases and phosphatases act antagonistically to maintain physiological phosphorylation/dephosphorylation at numerous intracellular sites critical for neuronal signalling. In this study, it was found that inhibition of serine/threonine phosphatases by exposure of hippocampal slices to okadaic acid (OA) or cantharidin (CA; 100 nmol/L) for 2 h resulted in reduced basal synaptic transmission and blocked the induction of synaptic plasticity in the form of long‐term potentiation as determined by electrophysiological analysis. Fura‐2 Ca2+ imaging revealed a bidirectional modulation of N‐methyl‐d‐aspartate (NMDA) ‐mediated Ca2+ responses and reduced KCl‐mediated Ca2+ responses in neonatal cultured hippocampal neurons after phosphatase inhibition. While OA inhibited NMDA‐induced Ca2+ influx both acutely and after incubation, CA‐enhanced receptor‐mediated Ca2+ signalling at low concentrations (1 nmol/L) but reduced NMDA and KCl‐mediated Ca2+ responses at higher concentrations (100 nmol/L). Changes in Ca2+ signalling were accompanied by increased phosphorylation of cytoskeletal proteins tau and neurofilament and the NMDA receptor subunit NR1 in selective treatments. Incubation with OA (100 nmol/L) also led to the disruption of the microtubule network. This study highlights novel signalling effects of prolonged inhibition of protein phosphatases and suggests reduced post‐synaptic signalling as a major mechanism for basal synaptic transmission and long‐term potentiation impairments.
Nidogen is a prosurvival and promigratory factor for adult Schwann cells
Authors: Lee Hyun Kyoung , Seo In Ae , Park Hye Kyung , Park Yoo Mi , Ahn Kyoung Jin , Yoo Young Hyun , Park Hwan Tae
Published: May 2007

Schwann cells provide a favorable microenvironment for successful regeneration of the injured peripheral nerve. Even though the roles of extracellular matrix proteins in the Schwann cell physiology have long been studied, the precise function of nidogen, a ubiquitous component of the basal lamina, in Schwann cells is unknown. In this study, we show that the protein and mRNA messages for nidogens are up‐regulated in the sciatic nerve after sciatic nerve transection. We demonstrate that recombinant nidogen‐1 increased the process formation of Schwann cells cultured from adult rat sciatic nerves and that nidogen‐1 prevented Schwann cells from serum‐deprivation‐induced death. In addition, nidogen‐1 promoted spontaneous migration of Schwann cells in two‐independent migration assays. The Schwann cell responses to the recombinant nidogen‐1 were specific because the nidogen‐binding ectodomain of tumor endothelial marker 7 inhibited the nidogen responses without affecting Schwann cell response to laminin. Finally, we found that β1 subunit‐containing integrins play a key role in the nidogen‐induced process formation, survival, and migration of Schwann cells. Altogether, these results indicate that nidogen has a prosurvival and promigratory activity on Schwann cells in the peripheral nerve.
Lysophosphatidic acid rescues RhoA activation and phosphoinositides levels in astrocytes exposed to ethanol
Authors: Martínez Susana E. , Lázaro‐Diéguez Francisco , Selva Javier , Calvo Fernando , Piqueras Jaime‐Renau , Crespo Piero , Claro Enrique , Egea Gustavo
Published: May 2007

Long‐term ethanol treatment substantially impairs glycosylation and membrane trafficking in primary cultures of rat astrocytes. Our previous studies indicated that these effects were attributable to a primary alteration in the dynamics and organization of the actin cytoskeleton, although the molecular mechanism(s) remains to be elucidated. As small Rho GTPases and phosphoinositides are involved in the actin cytoskeleton organization, we now explore the effects of chronic ethanol treatment on these pathways. We show that chronic ethanol treatment of rat astrocytes specifically reduced endogenous levels of active RhoA as a result of the increase of in the RhoGAP activity. Furthermore, ethanol‐treated astrocytes showed reduced phosphoinositides levels. When lysophosphatidic acid was added to ethanol‐treated astrocytes, it rapidly reverted actin cytoskeleton reorganization and raised active RhoA levels and phosphoinositides content to those observed in untreated astrocytes. Overall, our results indicate that the harmful effects of chronic exposure to ethanol on a variety of actin dynamics‐associated cellular events are primarily because of alterations of activated RhoA and phosphoinositides pools.
Capsaicin‐induced apoptosis of glioma cells is mediated by TRPV1 vanilloid receptor and requires p38 MAPK activation
Authors: Amantini C , Mosca M , Nabissi M , Lucciarini R , Caprodossi S , Arcella A , Giangaspero F , Santoni G
Published: May 2007

We provide evidence on the expression of the transient receptor potential vanilloid type‐1 (TRPV1) by glioma cells, and its involvement in capsaicin (CPS)‐induced apoptosis. TRPV1 mRNA was identified by quantitative RT‐PCR in U373, U87, FC1 and FLS glioma cells, with U373 cells showing higher, and U87, FC1 and FLS cells lower TRPV1 expression as compared with normal human astrocytes. By flow cytometry we found that a substantial portion of both normal human astrocytes, and U87 and U373 glioma cells express TRPV1 protein. Moreover, we analyzed the expression of TRPV1 at mRNA and protein levels of glioma tissues with different grades. We found that TRPV1 gene and protein expression inversely correlated with glioma grading, with marked loss of TRPV1 expression in the majority of grade IV glioblastoma multiforme. We also described that CPS trigger apoptosis of U373, but not U87 cells. CPS‐induced apoptosis involved Ca2+influx, p38 but not extracellular signal‐regulated mitogen‐activated protein kinase activation, phosphatidylserine exposure, mitochondrial permeability transmembrane pore opening and mitochondrial transmembrane potential dissipation, caspase 3 activation and oligonucleosomal DNA fragmentation. TRPV1 was functionally implicated in these events as they were markedly inhibited by the TRPV1 antagonist, capsazepine. Finally, p38 but not extracellular signal‐regulated protein kinase activation was required for TRPV1‐mediated CPS‐induced apoptosis of glioma cells.
A glycogen phosphorylase inhibitor selectively enhances local rates of glucose utilization in brain during sensory stimulation of conscious rats: implications for glycogen turnover
Authors: Dienel Gerald A. , Ball Kelly K. , Cruz Nancy F.
Published: May 2007

Glycogen is degraded during brain activation but its role and contribution to functional energetics in normal activated brain have not been established. In the present study, glycogen utilization in brain of normal conscious rats during sensory stimulation was assessed by three approaches, change in concentration, release of 14C from pre‐labeled glycogen and compensatory increase in utilization of blood glucose (CMRglc) evoked by treatment with a glycogen phosphorylase inhibitor. Glycogen level fell in cortex, 14C release increased in three structures and inhibitor treatment caused regionally selective compensatory increases in CMRglc over and above the activation‐induced rise in vehicle‐treated rats. The compensatory rise in CMRglc was highest in sensory‐parietal cortex where it corresponded to about half of the stimulus‐induced rise in CMRglcf in vehicle‐treated rats; this response did not correlate with metabolic rate, stimulus‐induced rise in CMRglc or sequential station in sensory pathway. Thus, glycogen is an active fuel for specific structures in normal activated brain, not simply an emergency fuel depot and flux‐generated pyruvate greatly exceeded net accumulation of lactate or net consumption of glycogen during activation. The metabolic fate of glycogen is unknown, but adding glycogen to the fuel consumed during activation would contribute to a fall in CMRO2/CMRglc ratio.
Isolation and characterization of novel microsatellite loci for parentage assessment in the lance‐tailed manakin (Chiroxiphia lanceolata)
Authors: DUVAL EMILY H. , CARTER KIM L. , KEMPENAERS BART
Published: May 2007

The lance‐tailed manakin (Chiroxiphia lanceolata) is a lek‐breeding bird from Central America in which males court females with complex cooperative displays. To resolve detailed patterns of paternity in the wild, we isolated and characterized 12 novel microsatellite loci in this species. Eleven of these loci were polymorphic (five to 14 alleles), with observed heterozygosities ranging from 0.36 to 0.87 (N = 574 individuals). We tested for linkage disequilibrium using randomized subsamples of adults to control for known family structure among long‐lived and sedentary individuals. These loci will be valuable in resolving paternity among many candidate fathers in this species.
Lack of association between rifampicin plasma concentration and treatment‐related side effects in osteoarticular infections
Authors: Roblot France , Besnier Jean‐Marc , Giraudeau Bruno , Simonnard Nicolas , Jonville‐Bera Annie‐Pierre , Coipeau Patrick , Choutet Patrick , Autret‐Leca Elisabeth , Le Guellec Chantal
Published: May 2007

The aim of this study was to assess the frequency of gastrointestinal side effects (GSE) and hepatotoxicity in patients treated with rifampicin for an osteoarticular infection and to determine if there is an association between rifampicin plasma concentrations and side effects. Rifampicin plasma concentrations were prospectively measured before (trough concentration, C0) and 2 ± 0.5 h (peak concentration, C2) after drug intake. The presence of GSE, the alanine transferase (ALT) value, and concomitantly administered medications were recorded on the day rifampicin concentrations were measured. C0 and C2 were compared for differences regarding the presence or absence of side effects. Multivariate analysis was performed, with associated medications being taken into account. Seventy C0 and 57 C2 values were measured in 46 adults after a median treatment of 8 days (range, 1–179). Wide inter‐individual variability was observed for C0 and C2. Thirteen (28%) patients reported GSE at least once. When GSE occurred, C0 (median, 1 mg L−1; range, 0.1–9.9 mg L−1) and C2 (median, 10.3 mg L−1; range, 1.8–40.3 mg L−1) were similar to C0 (median, 0.6 mg L−1; range, 0.1–10.3 mg L−1) and C2 (median, 10.9 mg L−1; range, 2.9–29.0 mg L−1) without GSE. The ALT value was more than normal in only three patients (6.5%) after rifampicin treatment began. The patients received no different associated medications whether or not GSE were present. Multivariate analysis showed no association between rifampicin plasma concentrations and GSE. GSE occur frequently in patients receiving rifampicin for osteoarticular infection but without an association with rifampicin plasma concentrations. Thus, therapeutic drug monitoring of rifampicin is irrelevant in the management of GSE.
Basic Science and Dialysis: Disturbances of Acquired Immunity in Hemodialysis Patients
Authors: Eleftheriadis Theodoros , Antoniadi Georgia , Liakopoulos Vassilios , Kartsios Charalambos , Stefanidis Ioannis
Published: May 2007

Acquired immunity disturbances in hemodialysis (HD) patients are many and diverse. They are caused by uremia per se, the HD procedure, chronic renal failure complications, and therapeutic interventions for their treatment. Current data suggest that acquired immunity disturbances in HD patients concern mainly the T‐lymphocyte and the antigen‐presenting cell (APC). The T‐lymphocyte‐dependent immune response is deficient, predisposing to infections and inadequate response to vaccinations. In addition, APCs are preactivated, which seems to be responsible for the malnutrition–inflammation–atherosclerosis syndrome, and also affects T‐lymphocyte function. At the molecular level it is assumed that the interaction between the APC and the T‐lymphocyte is impaired. This disturbance is likely to concern the signal that results from the interaction between the major histocompatibility complex:peptide complex on APC surfaces and T‐cell receptors on T‐lymphocyte surfaces, or the signal that results from the interaction among the co‐receptors of these two cells. The aim of the present review was to collect and classify the available clinical and experimental data in this area. Although many pieces are still missing from the puzzle, a better understanding of the responsible molecular mechanisms, will potentially lead to increased survival and a better quality of life in HD patients.
Model Checking for ROC Regression Analysis
Authors: Cai Tianxi , Zheng Yingye
Published: May 2007

Summary The receiver operating characteristic (ROC) curve is a prominent tool for characterizing the accuracy of a continuous diagnostic test. To account for factors that might influence the test accuracy, various ROC regression methods have been proposed. However, as in any regression analysis, when the assumed models do not fit the data well, these methods may render invalid and misleading results. To date, practical model‐checking techniques suitable for validating existing ROC regression models are not yet available. In this article, we develop cumulative residual‐based procedures to graphically and numerically assess the goodness of fit for some commonly used ROC regression models, and show how specific components of these models can be examined within this framework. We derive asymptotic null distributions for the residual processes and discuss resampling procedures to approximate these distributions in practice. We illustrate our methods with a dataset from the cystic fibrosis registry.
Semiparametric Bayesian Inference for Multilevel Repeated Measurement Data
Authors: Müller Peter , Quintana Fernando A. , Rosner Gary L.
Published: May 2007

SummaryWe discuss inference for data with repeated measurements at multiple levels. The motivating example is data with blood counts from cancer patients undergoing multiple cycles of chemotherapy, with days nested within cycles. Some inference questions relate to repeated measurements over days within cycle, while other questions are concerned with the dependence across cycles. When the desired inference relates to both levels of repetition, it becomes important to reflect the data structure in the model. We develop a semiparametric Bayesian modeling approach, restricting attention to two levels of repeated measurements. For the top‐level longitudinal sampling model we use random effects to introduce the desired dependence across repeated measurements. We use a nonparametric prior for the random effects distribution. Inference about dependence across second‐level repetition is implemented by the clustering implied in the nonparametric random effects model. Practical use of the model requires that the posterior distribution on the latent random effects be reasonably precise.
Our Future as History
Authors: Louis Thomas A.
Published: May 2007

Summary These are exciting and challenging times for the International Biometric Society and professional societies in general. These challenges require that we actively plan for our future and consider “Our Future as History”; that which lies ahead becomes the present and the present becomes history. To plan for the future I build on themes identified in my presidential address in Montréal, outlining our current status and initiatives, predicting and highlighting implications that call for expansion of our current activities and creation of new ones. These will ensure that we create our desired future and thereby produce a proud legacy.
A Note on Testing Separability in Spatial‐Temporal Marked Point Processes
Authors: Assunção Renato , Maia Alexandra
Published: May 2007

Summary In environmental risk analysis, it is common to assume the stochastic independence (or separability) between the marks associated with the random events of a spatial‐temporal point process. Schoenberg (2004, Biometrics60, 471–481) proposed several test statistics for this hypothesis and used simulated data to evaluate their performance. He found that a Cramér‐von Mises‐type test is powerful to detect gradual departures from separability although it is not uniformly powerful over a large class of alternative models. We present a semiparametric approach to model alternative hypotheses to separability and derive a score test statistic. We show that there is a relationship between this score test and some of the test statistics proposed by Schoenberg. Specifically, all are different versions of weighted Cramér‐von Mises‐type statistics. This gives some insight into the reasons for the similarities and differences between the test statistics' performance. We also point out some difficulties in controlling the type I error probability in Schoenberg's residual test.
Drawbacks to Noninteger Scoring for Ordered Categorical Data
Authors: Senn Stephen
Published: May 2007

Summary A proposal to improve trend tests by using noninteger scores is examined. It is concluded that despite improved power such tests are usually inferior to the simpler integer scored approach.
Effect of three different dental health preventive programmes on young adult individuals: a randomized, blinded, parallel group, controlled evaluation of oral hygiene behaviour on plaque and gingivitis
Authors: Hugoson Anders , Lundgren Dan , Asklöw Barbro , Borgklint Gun
Published: May 2007

Aim:To evaluate, in young adults, the effect of different preventive programmes on oral hygiene and to determine whether the variables investigated are predictors of gingival health.

Material and Methods:This randomized, blinded, parallel, controlled clinical study examined the effectiveness of three dental health programmes. Four hundred subjects aged 20–27 years, 211 males and 189 females, participated in the study. They were recruited from a Public Dental Service clinic and from a private dental practice in Jönköping, Sweden. The effect of the programmes on plaque and gingivitis was evaluated over a 3‐year period. The programmes included activities that were adapted for individuals as well as for groups. The plaque indices (PLI) and gingival indices (GI) were used to evaluate the programmes.

Results:All programmes resulted in a decrease in PLI and GI. The greatest decrease was found in the group that was followed‐up every 2 months. Professional tooth cleaning was non‐significant for the clinical result. Gingival health at baseline, participation in any of the test programmes, and knowledge of the dental diseases caries, gingivitis or periodontitis were significant predictors of good gingival health.

Conclusions:The study confirms the efficacy of three different preventive programmes in reducing supragingival plaque and gingival inflammation. Professional tooth cleaning provided no clinical benefit beyond that derived from individual and group‐based health education.
Gingival blood flow changes following periodontal access flap surgery using laser Doppler flowmetry
Authors: Retzepi M. , Tonetti M. , Donos N.
Published: May 2007

Aim: To investigate the pattern of gingival blood flow changes following periodontal access flap surgery by laser Doppler flowmetry (LDF).

Material and methods: Fourteen patients with chronic periodontitis presenting upper anterior sites with pocket depth 5 mm after initial treatment were included in the study. Periodontal access flap surgery was performed on the experimental areas and LDF recordings were taken at baseline, following anaesthesia, immediately postoperatively and on days 1, 2, 3, 4, 7, 15, 30 and 60 of healing, at nine predetermined sites per flap.

Results: Significant ischaemia was observed at all flap sites following anaesthesia and immediately postoperatively. At the alveolar mucosal sites, a peak increase of the gingival blood flow was observed on postoperative day 1 (p<0.001), which persisted until day 7 (p=0.012) and resolved by day 15. The mucosal sites close to the flap periphery presented higher blood perfusion compared with the sites located centrally in the flap. The microcirculatory perfusion of the buccal and palatal papillae was maximum on postoperative day 7 (p=0.013 and <0.001, respectively) and returned to baseline by day 15.

Conclusion: Topographically distinct areas of the periodontal access flap consistently present different patterns of microvascular blood flow alterations during the wound‐healing period.
Bone formation at rhBMP‐2‐coated titanium implants in the rat ectopic model
Authors: Hall Jan , Sorensen Rachel G. , Wozney John M. , Wikesjö Ulf M.E.
Published: May 2007

Background: The objective of this study was to evaluate local bone formation at titanium porous oxide (TPO) implant surfaces adsorbed with recombinant human bone morphogenetic protein‐2 (rhBMP‐2).

Methods: In vitro studies were used to estimate the kinetics of I125‐labeled rhBMP‐2 released from TPO surfaces with narrow (N) or open (O) pores. Machined/turned titanium (MT) surfaces served as control. The rat ectopic model was used to assess local bone formation. Briefly, TPO‐N, TPO‐O, and MT disc implants adsorbed with 5, 10, or 20 μg rhBMP‐2, respectively, were implanted subcutaneously into the ventral thoracic region in 5‐week‐old male Long Evans rats. The animals were euthanized at day 14 postsurgery when implants with surrounding tissues were removed, radiographed, and gross observations recorded. The specimens were processed for histologic evaluation using conventional cut‐and‐grind techniques. TPO implants without rhBMP‐2 included in a preliminary evaluation revealed no evidence of bone formation, tissue encapsulation, or vascularity, thus such controls were not further used.

Results: TPO and MT implant surfaces adsorbed with 5 μg rhBMP‐2 retained 2.3–5.4% rhBMP‐2 following immersion and rinse in buffer, and 1.1–2.2% rhBMP‐2 following repeated immersions and rinses over 27 days. TPO implants retained the most rhBMP‐2 and MT implants retained the least. Explants revealed increased hard tissue formation, tissue encapsulation, and vascularity at TPO compared with MT implants. Radiographic observations were consistent with the explant observations. The histologic analysis showed greater amounts of bone formation, osteoblastic cells, osteoid, marrow, tissue encapsulation, vascularity, and bone voids for implants adsorbed with 10 and 20 μg rhBMP‐2, and for TPO implants at the 5‐μg rhBMP‐2 dose. The histometric analysis revealed significantly greater bone formation at TPO‐O than at MT implants at the 5‐μg rhBMP‐2 dose. All surfaces showed significant bone formation at the 10‐ and 20‐μg dose.

Conclusions: rhBMP‐2 adsorbed onto TPO implant surfaces executes an osteoinductive effect including bone contacting the implant surface. This effect is surface‐ and dose‐dependent; the TPO‐O surface yielding the most bone at the low discriminating rhBMP‐2 dose.
The new concept of periodontal disease pathogenesis requires new and novel therapeutic strategies
Authors: Taubman Martin A. , Kawai Toshihisa , Han Xiaozhe
Published: May 2007

In this issue Bostanci et al. (2007) demonstrate that receptor activator of NF‐κB ligand (RANKL) and osteoprotegerin (OPG) were oppositely regulated in gingival crevice fluid (GCF) from periodontitis patients. RANKL, RANK and OPG are key molecules that regulate osteoclast recruitment, differentiation and activation. New concepts of the pathogenesis of periodontitis have implicated inflammation triggered by host immune response to periodontal biofilm microorganisms(s) in disease. Host response to bacteria involves activation of T and B cells in the inflammatory infiltrate which bear abundant RANKL that promotes osteoclastic bone resorption. Periodontal tissue destruction can be ameliorated by immunobiological interference with immune cell RANKL expression or function. The new disease concepts provide a foundation to build biological approaches to target RANKL production in periodontal lesions.
Polymorphisms in the CD14 and IL‐6 genes associated with periodontal disease
Authors: Tervonen Tellervo , Raunio Taina , Knuuttila Matti , Karttunen Riitta
Published: May 2007

Aim: To compare the frequencies of cytokine and receptor molecule genotypes in patients with chronic periodontitis with the corresponding frequencies in a reference population and to study the relationship between periodontal disease severity and polymorphisms in the studied genes.

Subjects and methods: CD14, IL‐6, TNF‐α, IL‐10, IL‐1α, IL‐1β, and TLR‐4 polymorphisms of 51 periodontitis patients were studied using polymerase chain reaction. The genotype frequencies in the periodontitis patients and a reference population (n=178) were compared. Probing pocket depth (PD), periodontal attachment level (AL), and alveolar bone level (BL) were related to the genotypes.

Results: No statistically significant differences could be found between the frequencies of the cytokine genotypes in the periodontitis patients and in the reference group. The extent of periodontal disease was higher in subjects with the T‐containing genotype of CD14−260 and the GG genotype of IL‐6−174 when compared with the extent in the rest of the group. Subjects carrying the composite genotype of the above two were most severely affected by periodontal disease.

Conclusion: According to the present results, an evident association exists between the carriage of the T‐containing genotype of CD14−260 and the GG genotype of IL‐6−174 and the extent periodontal disease.
Early patient contact in undergraduate dental education in Germany –‘The Greifswald Model’
Authors: Ratzmann A. , Wiesmann U. , Gedrange T. , Kordaß B.
Published: May 2007

Summary  Revised regulations in Germany have allowed new curricular concepts to be introduced into the undergraduate dental curriculum. In the first 2 years of the dental curriculum at the University of Greifswald, a new teaching concept which is based on the interactions between Community Medicine and Dentistry has been introduced. It emphasises the importance of early patient contact in providing experience for students. The course consists of three principal elements: student–patient contacts in the patient's home; problem‐based learning tutorials to discuss patient cases; and special training in communication skills. The aim of the course is to give students an insight into the patient's view of the illness and treatment, and the effect of their condition on his or her lifestyle. The students also learn about the communal perspective (health survey, intervention planning and implementation in a community). The first four courses were evaluated by questionnaires from the students before and after the 2‐year course to assess the concept from the students’ perspective. The results indicate that it is possible to provide considerable improvement of the medical/dental education as regards communication skills and understanding of the patients’ perceptions, by letting the student establish contact with patients at the very beginning of the curriculum.