bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation of Nerve Terminals from Crustacean Muscle
Authors: Santiapillai Nirmala F. , Gray Sally R. , Phillips R. Elizabeth , Richardson Peter J.
Published: October 2006

Abstract: A method for the isolation of γ‐aminobutyric acid‐ergic (GABAergic) and glutamatergic terminals from crustacean muscle was developed, using differential centrifugation and sucrose density gradient centrifugation. Individual fractions were assessed using a variety of markers. One fraction was isolated which showed 40‐fold purification of glutamate decarboxylase with a yield of 12%. This fraction was enriched in GABA, glutamate, glutamate dehydrogenase, and 5′‐nu‐cleotidase, but not in NADPH cytochrome c reductase. This fraction possessed an uptake system for GABA and glutamate with apparent kinetic constants of Km= 50 μM, Vmax= 250 pmol/min/mg of protein and Km ‐ 183 μM, Vmax= 219 pmol/min/mg of protein, respectively. Electron microscopy showed nerve terminal profiles and a heterogeneous population of membrane vesicles. This fraction contained 3.4 nmol ATP/mg of protein which was stable for 30 min at 12°C, and was also able to synthesise ATP from exogenous adenosine. The terminals released labelled GABA and glutamate in a Ca2+‐dependent fashion on depolarisation. No release of ATP was detected. It is concluded that viable nerve terminals have been isolated which could be used as model systems for the study of GABAergic and glutamatergic neuro‐chemistry.
Production of Hyperalgesic Prostaglandins by Sympathetic Postganglionic Neurons
Authors: Gonzales Ralph , Goldyne Marc E. , Taiwo Yetunde O. , Levine Jon D.
Published: October 2006

Abstract: Prostaglandin E2 and prostacyclin (prostaglandin 12) produce hyperalgesia in animals and humans. Because there is evidence that prostaglandins contribute to pain maintained by sympathetic nervous system activity, we evaluated whether sympathetic postganglionic neurons synthesize these hyperalgesic prostaglandins, and whether production of prostaglandins by these neurons can contribute to sensitization of primary afferent nociceptors. Intradermal injection of arachidonic acid but not linoleic acid, in the rat hindpaw, produces a decrease in mechanical nociceptive threshold. This hyperalgesic effect is prevented by indomethacin, an inhibitor of prostaglandin synthesis or by prior surgical removal of the lumbar sympathetic chain. To test the hypothesis that sympathetic postganglionic neurons are the source of prostaglandins, we measured production of prostaglandin E2 and 6‐keto‐prostaglandin Flα (the stable metabolite of prostacyclin) by homogenates of adult rat sympathetic postganglionic neurons from superior cervical ganglia. These homogenates produced significant amounts of prostaglandin E2 and 6‐keto‐prostaglandin F1α, and most of this production is eliminated by neonatal administration of 6‐hydroxydopamine which selectively destroys sympathetic postganglionic neurons. These results demonstrate that sympathetic postganglionic neurons produce prostaglandins, and supports further the hypothesis that the release of prostaglandins from sympathetic postganglionic neurons contributes to the hyperalgesia associated with sympathetically maintained pain.
Simultaneous In Vivb Monitoring of Cerebral Deoxyglucose and Deoxyglucos‐6‐Phosphate by l3C{lH} Nuclear Magnetic Resonance Spectroscopy
Authors: Kotyk John J. , Rust Robert S. , Ackerman Joseph J. H. , Deuel Ruthmary K.
Published: October 2006

Abstract: The capacity of brain to dephosphoirylate glucose‐6‐phosphate has been established, but the magnitude and significance of this capacity in vivo are debated, particularly in regard to dephosphorylation of the glucose analog 2‐de‐oxyglucose. We now report results of external m easurement in the brains of conscious rats with simultaneous resolution and quantification of both 2‐deoxyglucose and its phosphor‐ylated product by nuclear magnetic resonance (NMR) techniques that used 2‐[6‐l3C]deoxyglucose together with proton‐decoupled 13C surface‐coil spectroscopy. As NMR techniques require large doses of 2‐deoxyglucose, a dose comparison was first made using decay curves of total label after tracer doses of 2‐[14C]deoxyglucose without versus with unlabeled deoxyglucose at 500 mg/kg (the NMR dose). Similar cerebral half‐lives for the two doses were found, and no behavioral evidence for toxicity of the NMR dose was seen. In vivo NMR monitoring of conscious rats showed that the analog reached maximal cerebral concentration within 10 min of the intravenous bolus and decayed with a half‐life of 29 ± 7 min (n = 4; mean ± SEM), whereas 2‐deoxyglucose‐6‐phos‐phate reached peak concentration between 30 and 40 min and decayed with a half‐life of 2.1 ± 0.3 h, equivalent to a fractional loss of 0.8%/min. Thirty‐one percent (±5%) of the total analog pool (which showed a half‐life of 1.4 h) consisted of 2‐deoxyglucose at 45 min after the bolus. The results support an active but limited role for dephosphorylation by normal brain in glucose analog (and potentially glucose) metabolism in the unstimulated conscious rat and a wide concentration range for the metabolic operations involved.
Acute Choline Supplementation In Vivo Enhances Acetylcholine Synthesis In Vitro when Neurotransmitter Release Is Increased by Potassium
Authors: Wecker Lynn , Cawley George , Rothermel Sheila
Published: October 2006

Abstract: The main objective of these studies was to determine whether the acute administration of choline to rats provides supplemental precursor that can be used to support acetylcholine synthesis when the demand for choline is increased by increasing neurotransmitter release. For these experiments, hippocampal and striatal slices were prepared from rats that had received saline or an acute injection of choline. Slices were incubated in a choline‐free buffer containing 4.74–35 mM KC, and acetylcholine synthesis and release and choline production were measured. The initial tissue contents of acetylcholine and choline did not differ between experimental groups for either brain region. When hippocampal slices from the controls were incubated for 10 min with depolarizing concentrations of KCl, acetylcholine release increased and the tissue content decreased in a concentration‐dependent fashion; no net synthesis of acetylcholine occurred. In contrast, hippocampal slices from the choline‐injected animals maintained their tissue content in the presence of high concentrations of KCl, despite an increase in acetylcholine release that was similar in magnitude to that of the controls; positive net synthesis of acetylcholine resulted. Although the molar concentration of choline achieved in the incubation media at the end of the 10‐min period did not differ between groups, the mobilization of free choline from bound stores was significantly greater in hippocampal slices from the choline‐injected group than the controls. In addition, the synthesis of acetylcholine by hippocampal slices from the cholineinjected group was prevented by the presence of hemicholinium‐3 (1 μM) in the media. Acetylcholine synthesis and choline mobilization by striatal slices did not differ between groups. Results demonstrate that acute supplementation with choline provides precursor to support acetylcholine synthesis when the release of neurotransmitter is increased.
Changes in Excitatory Amino Acid Receptor Binding in the Intact and Decorticated Rat Neostriatum Following Insulin‐Induced Hypoglycemia
Authors: Westerberg Eva , Wieloch Tadeusz W.
Published: October 2006

Abstract: An involvement of excitatory amino acid (EAA) transmitter–receptor interactions in the development of hypoglycemia‐induced neuronal damage has been suggested. We report here on the binding to EAA receptors in the rat caudate nucleus and cerebral cortex, during and following severe insulin‐induced hypoglycemia with an isoelectric EEG of 10 or 30 min duration. The binding of α[3H]amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid ([3H]AMPA) to quisqualate receptors, [3H]kainic acid (KA) to kainate receptors, and [3H]glutamate to N‐methyl‐D‐aspartate (NMDA)‐sensitive sites was determined by quantitative autoradiography. During EEG isoelectricity, AMPA binding was reduced by approximately 40%, which could represent quisqualate receptor desensitization. One hour following glucose‐induced recovery, AMPA binding was no longer different from control level. As the recovery period was prolonged to 1 or 4 weeks, AMPA binding decreased. The decrease was more pronounced in the dorsolateral than in the ventromedial part of the striatum. This correlates with the distribution of neuronal damage, and probably reflects loss of receptor binding sites due to cell death. During the period of EEG silence there was a tendency toward an increase in NMDA displaceable glutamate binding. Following 4 weeks of recovery, binding to NMDA receptors was significantly decreased. Glutamate binding to NMDA‐sensitive sites was remarkably resistant to neuronal necrosis and was not significantly different from control values in the dorsolateral caudate 1 week following the hypoglycemic coma. No changes in KA binding were found until 1 week posthypoglycemia, when a significant reduction in binding was noted in the lateral striatum. Two weeks following partial unilateral cortical ablation, binding to NMDA receptors in the striatum decreased in the lesioned hemisphere in control animals and remained significantly lower than in the contralateral hemisphere during EEG isoelectricity. In contrast, no hemispheric differences in AMPA binding were observed. The lack of desensitization of NMDA receptors during EEG isoelectricity and their relative resistance to neuronal necrosis could be of significance for the development of hypoglycemic neuronal damage.
Changes in Histamine Metabolism in the Brains of Mice with Streptozotocin‐Induced Diabetes
Authors: Nishibori Masahiro , Oishi Ryozo , Itoh Yoshinori , Saeki Kiyomi
Published: October 2006

Abstract: Histamine (HA) metabolism in the brain of mice with streptozotocin (STZ)‐induced diabetes was examined. The levels of tele‐methylhistamine (t‐MH), a major metabolite of brain HA, significantly increased 3 and 4 weeks after STZ injection. However, the HA turnover rates in the diabetic mice, determined from the accumulation of t‐MH after the administration of pargyline, were not different from the control values when the animals were allowed free access to food. When the mice were starved for 15 h 4 weeks after STZ treatment, the brain levels of l‐histidine decreased significantly, whereas HA turnover increased significantly. Such changes were not observed in starved control mice. Histidine decarboxylase or HA N‐methyltransferase activity did not change after starvation in either diabetic or control mice. These results show that the histaminergic (HAergic) activity in the brains of diabetic mice remains within normal range as long as the animals are allowed free access to food. However, they also indicate that a marked enhancement of HAergic activity accompanied by a decrease in the brain l‐histidine level occurs in starved diabetic mice.
Expression of Functional Human Monoamine Oxidase A and B cDNAs in Mammalian Cells
Authors: Lan Nancy C. , Chen Chonghong , Shih Jean C.
Published: October 2006

Abstract: Monoamine oxidase (MAO) A and B are important enzymes that metabolize biogenic amines throughout the body. Previous studies had suggested that both MAO A and B consist of two subunits of molecular masses of 63 and 60 kilodaltons, respectively. The cDNAs encoding one subunit of human liver MAO A and B have been expressed in mammalian cells by transfection of the individual clones. The proteins expressed from these cDNAs are shown to be catalytically active. Similar to the endogenous enzymes, the expressed MAO A prefers serotonin as a substrate and is sensitive to the inhibitor clorgyline. In contrast, the expressed MAO B prefers phenylethyl‐amine as a substrate and is sensitive to the inhibitor deprenyl. These results suggest that a single polypeptide of MAO A (or B), existing as either a monomer or homodimer, is enzymatically active. The ability to obtain functional MAO A and B from their respective cDNA clones allows us to study further the structure and function relationships of these important enzymes.
Stimulation of Inositol Phospholipid Hydrolysis by Excitatory Amino Acids Is Enhanced in Brain Slices from Vulnerable Regions after Transient Global Ischemia
Authors: Seren M. S. , Aldinio C. , Zanoni R. , Leon A. , Nicoletti F.
Published: October 2006

Abstract: Stimulation of inositol phospholipid hydrolysis by transmitter receptor agonists was measured in slices from hippocampus, cerebral cortex, and corpus striatum at various intervals after transient global ischemia in rats. Ischemia was induced through the four‐vessel occlusion model. Stimulation of [3H]inositol monophosphate formation by excitatory amino acids was greatly enhanced in hippocampal slices prepared from ischemic rats at 24 h or 7 days after reperfusion. This potentiation was more evident using ibotenic acid and was also observed in cerebral cortex, but not in corpus striatum. This regional profile correlated with the pattern of ischemia‐induced neuronal damage observed under our experimental conditions. The enhanced responsiveness to excitatory amino acids was always accompanied by an increase in both basal and norepinephrine‐stimulated [3H]inositol monophosphate formation. In contrast, stimulation of [3H]inositol monophosphate formation by carbamylcholine was not modified in hippocampal or cortical slices from ischemic animals
Antioxidant Enzymes and Related Trace Elements in Aging Brain Capillaries and Choroid Plexus
Authors: Tayarani Ivan , Cloëz Isabelle , Clément Michel , Bourre Jean‐Marie
Published: October 2006

The activities of superoxide dismutase (SOD), glutathione peroxidase, glutathione reductase, and catalase were measured in isolated brain capillaries, choroid plexus, cerebrum, and cerebellum from rats of 2, 6, 12, and 24 months. The contents of copper, zinc, and manganese were determined in capillaries, cerebrum, and cerebellum, and the profile of fatty acids was studied in brain capillaries. In brain capillaries, the activities of glutathione peroxidase and glutathione reductase did not change with age. The activities of the two enzymes increased in cerebrum and cerebellum. In choroid plexus, glutathione peroxidase activity increased, but glutathione reductase activity remained unchanged. Catalase activity in brain capillaries declined, whereas in choroid plexus, cerebrum, and cerebellum, it did not change. The activities of the three enzymes were significantly higher in brain capillaries and choroid plexus than in cerebrum and cerebellum. SOD activity increased in the four tissues. Copper content in the capillaries increased initially and then levelled off, whereas it continued to increase in cerebrum and cerebellum. Zinc increased in brain capillaries, but did not vary in cerebrum and cerebellum. Manganese content remained constant in all tissues studied. The percent of saturated fatty‐acids in brain capillaries did not change with age, whereas those of mono‐ and polyunsaturated fatty acids increased and decreased, respectively. The possibility that a deficiency of enzymes protective against free radicals causes blood‐brain barrier and blood‐cerebrospinal fluid barrier degeneration is ruled out.
Purification and Characterisation of Cerebellins from Human and Porcine Cerebellum
Authors: Yiangou Y. , Burnet P. , Nikou G. , Chrysanthou B. J. , Bloom S. R.
Published: October 2006

The primary human and porcine structure of the novel neuropeptide cerebellin is unknown. These peptides were, therefore, isolated by a combination of ion‐exchange and reverse‐phase chromatography using a specific radioimmunoassay against rat cerebellin. The sequences of the peptides were deduced by mass spectrometry (for both human and porcine cerebellins) and gas‐phase Edman degradation (for porcine cerebellin). In both species, two molecular forms were identified. In the human, the major form corresponded to the pentadecamer [des‐Ser1]‐cerebellin (˜95% of the total) and the minor form, to the hexadecamer peptide. In the pig. however, both molecular forms were present in approximately equal amounts. The finding that the sequences of human and porcine cerebellin are identical to that of the rat suggests that strong evolutionary pressure has acted to conserve this sequence.
Newly Synthesized Dopamine as the Precursor for Norepinephrine Synthesis in Bovine Adrenomedullary Chromaffin Cells
Authors: Menniti Frank S. , Diliberto Emanuel J.
Published: October 2006

The precursor pool of dopamine for norepinephrine synthesis was investigated in cultured bovine adrenomedullary chromaffin cells incubated with [14C]tyrosine. Under conditions where the intracellular [14C]tyrosine specific activity was constant and [14C]dopamine synthesis was maximal, [14C]dopamine and [14C]norepinephrine accumulated over time, and the total intracellular dopamine content more than doubled within 120 min. When [14C]norepinephrine synthesis was calculated at different times based on the specific activity of [14C]dopamine, this rate was approximately equal to the rate of [l4C]dopamine synthesis and was, thus, inconsistent with the observed dopamine accumulation. However, the rate of [14C]norepinephrine synthesis based on the [l4C]tyrosine specific activity accounted for the dopamine accumulation, an observation suggesting that newly synthesized dopamine, i.e., dopamine with a specific activity equivalent to that of its precursor, [14C]tyrosine, is preferentially utilized for norepinephrine synthesis. Further studies showed that the subcellular distribution of [14C]dopamine was identical to that of norepinephrine and epinephrine and that the accumulated [14C]dopamine could be converted to norepinephrine within the chromaffin vesicle if dopamine uptake was blocked. Taken together, these results suggest that a small intravesicular dopamine pool, rapidly replenished by newly synthesized dopamine, serves as the substrate for dopamine β‐hydroxylase. Several mechanisms to account for this observation are discussed.
Calcium‐Dependent, Tetrodotoxin‐Sensitive Stimulation of Cortical Serotonin Release After a Tryptophan Load
Authors: Carboni E. , Cadoni C. , Tanda G. L. , Di Chiara G.
Published: October 2006

The effect of intraperitoneal administration of tryptophan (50, 100, or 200 mg/kg) on extracellular concentrations of tryptophan, serotonin (5‐hydroxytryptamine, 5‐HT), and 5‐hydroxyindoleacetic acid (5‐HIAA) was studied in the cortex of freely moving rats by transcerebral dialysis. Rats were implanted with dialysis probes in the frontal cortex, and experiments were performed 24 h later. Tryptophan, 5‐HT, and 5‐HIAA were quantified in 20‐min samples of dialysate by HPLC with electrochemical detection after separation on reverse‐phase columns. Tryptophan administration resulted in a significant increase of tryptophan, 5‐HT, and 5‐HIAA levels in di‐alysates. The maximal increase of 5‐HT and 5‐HIAA output was ˜ 150% over basal values. Perfusion with Ringer's solution containing tetrodotoxin (1 μM) reduced 5‐HT output by 90% and prevented the increase of 5‐HT and 5‐HIAA content after 100 mg/kg of tryptophan. Similar results were obtained after perfusion with Ringer's solution without Ca2+. The results indicate that a tryptophan load stimulates the physiological release of 5‐HT.
In Vivo Modulation of the N‐Methyl‐D‐Aspartate Receptor Complex by D‐Serine: Potentiation of Ongoing Neuronal Activity as Evidenced by Increased Cerebellar Cyclic GMP
Authors: Wood Paul L. , Emmett Mark R. , Rao Tadimeti S. , Mick Steve , Cler Julie , Iyengar Smriti
Published: October 2006

Direct intracerebellar injections of TV‐methyl‐D‐aspartate (NMDA) or D‐serine elicited dose‐dependent increases in cerebellar cyclic GMP levels, in vivo in the mouse. The actions of D‐serine were antagonized by the competitive NMDA receptor antagonist 3‐(2‐carboxypiperazin‐4‐yl) propyl‐1‐phosphonic acid and by the phen‐cyclidine receptor agonist MK‐801, observations supporting actions at the NMDA‐coupled glycine receptor. In addition, the actions of D‐serine were antagonized by a partial agonist (D‐cycloserine) and an antagonist (HA‐966) of the NMDA‐coupled glycine receptor. These data are all consistent with D‐serine acting at the NMDA‐coupled glycine receptor and represent the first demonstration of glycine receptor potentiation of ongoing NMDA‐mediated neuronal activity in the CNS, rather than potentiation of exogenous NMDA.
An Improved HPLC‐Electrochemical Detection Method for Measuring Brain Levels of 5‐S‐Cysteinyldopamine, 5‐S‐Cysteinyl‐3,4‐Dihydroxyphenylalanine, and 5‐S‐Cysteinyl‐3,4‐Dihydroxyphenylacetic Acid
Authors: Fornstedt Bodil , Bergh Ingrid , Rosengren Evald , Carlsson Arvid
Published: October 2006

Brain levels of the 5‐S‐cysteinyl adducts of 3,4‐dihydroxyphenylalanine (DOPA), 3,4‐dihydroxyphenylacetic acid (DOPAC), and dopamine were determined in several mammalian species. The low levels of the compounds and the risk of artifacts during sample preparation necessitated rather profound modifications of the assaying method. The refined method has made it possible to present more accurate data than those previously reported from this laboratory. The occurrence of low levels of the 5‐S‐cysteinyl adducts in dopamine‐rich brain areas, but not in cerebellum, is indirect evidence of in vivo autoxidation of DOPA, DOPAC, and dopamine. The products generated during catechol autoxidation, including quinones and reduced forms of oxygen, are known to be potentially cytotoxic.
Diacylglycerol‐Induced Stimulation of Neurotransmitter Release from Rat Brain Striatal Synaptosomes
Authors: Davis Mary Ellen Nelson , Patrick Robert L.
Published: October 2006

These studies were undertaken to test the hypothesis that alterations in phosphatidylinositol metabolism can modulate neurotransmitter release in the central nervous system. The effects of 1,2‐diacylglycerols (DAGs) on dopamine release in the rat central nervous system were determined by measuring dopamine release from rat striatal synaptosomes in response to two DAGs (sn‐1,2‐dioctanoylglycerol and 1‐oleoyl‐2‐acetylglycerol) that can activate protein kinase C and one DAG (deoxydioctanoylglycerol) that does not activate this kinase. Dioctanoylglycerol and 1‐oleoyl‐2‐acetylglycerol, at a concentration of 50 μg/ml, stimulated the release of labeled dopamine from striatal synaptosomes by 35–50 and 17%, respectively. Dioctanoylglycerol‐induced release was also demonstrated for endogenous dopamine. In contrast, deoxydioctanoylglycerol (50 μg/ml) did not stimulate dopamine release. Dioctanoylglycerol‐induced dopamine release was independent of external calcium concentration, indicating a utilization of internal calcium stores. Dioctanoylglycerol (50 μg/ml) also produced a 38% increase in labeled serotonin release from striatal synaptosomes. The addition of dioctanoylglycerol to the striatal supernatant fraction increased protein kinase C activity. These results are consistent with the concept that an increase in phosphatidylinositol metabolism can stimulate neurotransmitter release in the central nervous system via an increase in DAG concentration. The data suggest an involvement of protein kinase C in the DAG‐induced release, but other sites for DAG action are also possible.
Ethanol Inhibition of N‐Methyl‐D‐Aspartate‐Stimulated Endogenous Dopamine Release from Rat Striatal Slices: Reversal by Glycine
Authors: Woodward John J. , Gonzales Rueben A.
Published: October 2006

N‐Methyl‐D‐aspartate stimulated a concentration‐dependent release of endogeneous dopamine from rat striatal slices. The threshold for activation was between 10 and 25 μM and reached a maximum at 1 mM. Release was completely blocked by magnesium or tetrodotoxin. Ethanol (10–200 mM) significantly inhibited the N‐methyl‐D‐aspartate‐stimulated release of dopamine by 20–45%, with half‐maximal inhibition occurring at ∼21 mM. Addition of ethanol plus increasing concentrations of magnesium resulted in a greater inhibition of N‐methyl‐D‐aspartate‐stimulated dopamine release than that observed with magnesium alone. However, this effect appeared to be due to a noninteractive additive effect of the two antagonists, as the IC50 value for magnesium inhibition was not significantly altered by ethanol. Glycine, which had no effect on dopamine release by itself, completely reversed the inhibitory effects of ethanol (25 mM) at low micromolar concentrations. These results suggest that ethanol may produce its effects in striatal slices by interfering with a glycine modulatory site of the N‐methyl‐D‐aspartate receptor‐ionophore complex.
Stimulation of Synaptosomal γ‐Aminobutyric Acid Synthesis by Glutamate and Glutamine
Authors: Battaglioli Gino , Martin David L.
Published: October 2006

γ‐Aminobutyric acid (GABA) synthesis was studied in rat brain synaptosomes by measuring the increase of GABA level in the presence of the GABA‐transaminase inhibitor gabaculine. The basal rate of synaptosomal GABA synthesis in glucose‐containing medium (25.9 nmol/h/mg of protein) was only 3% of the maximal activity of glutamate decarboxylase (GAD; 804 ± 83 nmol/h/mg of protein), a result indicating that synaptosomal GAD operates at only a small fraction of its catalytic capacity. Synaptosomal GABA synthesis was stimulated more than threefold by adding 500 μM glutamine. Glutamate also stimulated GABA synthesis, but the effect was smaller (1.5‐fold). These results indicate that synaptosomal GAD is not saturated by endogenous levels of its substrate, glutamate, and account for part of the unused catalytic capacity. The greater stimulation of GABA synthesis by glutamine indicates that the GAD‐containing compartment is more accessible to extrasynaptosomal glutamine than glutamate. The strong stimulation by glutamine also shows that the rates of uptake of glutamine and its conversion to glutamate can be sufficiently rapid to support GABA synthesis in nerve terminals. Synaptosomes carried out a slow net synthesis of aspartate in glucose‐containing medium (7.7 nmol/h/mg of protein). Aspartate synthesis was strongly stimulated by glutamate and glutamine, but in this case the stimulation by glutamate was greater. Thus, the larger part of synaptosomal aspartate synthesis occurs in a different compartment than does GABA synthesis.
Developmental and Regional Studies of the Metabolism of Inositol 1,4,5‐Trisphosphate in Rat Brain
Authors: Heacock Anne M. , Seguin Edward B. , Agranoff Bernard W.
Published: October 2006

Coupling of CNS receptors to phosphoinositide turnover has previously been found to vary with both age and brain region. To determine whether the metabolism of the second messenger inositol 1,4,5‐trisphosphate also displays such variations, activities of inositol 1,4,5‐trisphosphate 5′‐phosphatase and 3′‐kinase were measured in developing rat cerebral cortex and adult rat brain regions. The 5′‐phosphatase activity was relatively high at birth (∼50% of adult values) and increased to adult levels by 2 weeks postnatal. In contrast, the 3′‐kinase activity was low at birth and reached ∼50% of adult levels by 2 weeks postnatal. In the adult rat, activities of the 3′‐kinase were comparable in the cerebral cortex, hippocampus, and cerebellum, whereas much lower activities were found in hypothalamus and pons/medulla. The 5′‐phosphatase activities were similar in cerebral cortex, hippocampus, hypothalamus, and pons/medulla, whereas 5‐to 10‐fold higher activity was present in the cerebellum. The cerebellum is estimated to contain 50–60% of the total inositol 1,4,5‐trisphosphate 5′‐phosphatase activity present in whole adult rat brain. The localization of the enriched 5′‐phosphatase activity within the cerebellum was examined. Application of a histochemical lead‐trapping technique for phosphatase indicated a concentration of inositol 1,4,5‐trisphosphate 5′‐phosphatase activity in the cerebellar molecular layer. Further support for this conclusion was obtained from studies of Purkinje cell‐deficient mutant mice, in which a marked decrement of cerebellar 5′‐phosphatase was observed. These results suggest that the metabolic fate of inositol 1,4,5‐trisphosphate depends on both brain region and stage of development.
AUXOSPORE FORMATION BY THE SILICA‐SINKING, OCEANIC DIATOM FRAGILARIOPSIS KERGUELENSIS (BACILLARIOPHYCEAE)1
Authors: Assmy Philipp , Henjes Joachim , Smetacek Victor , Montresor Marina
Published: September 2006

Size restoration by the auxospore that develops from the zygote is a crucial stage in diatom life cycles. However, information on sexual events in pelagic diatom species is very limited. We report for the first time auxospore formation by the pennate diatom Fragilariopsis kerguelensis (O'Hara) Hustedt during an iron‐induced bloom in the Southern Ocean (EIFEX, European Iron Fertilization EXperiment). Auxospores of F. kerguelensis resembled those described for Pseudo‐nitzschia species. The auxospore was characterized by an outer coating, the perizonium; two caps, one at each distal end; and four chloroplasts, one at each end and two in the central part. Different stages of auxospore elongation were recorded, with a length of 24–91 μm, but only the largest auxospores contained the initial cell, whose apical axis ranged between 76 and 90 μm. Gametangial cell walls were often attached to the auxospores and ranged from 10 to 31 μm in length. Auxospore abundances were consistently higher in the fertilized patch, where an increase in the F. kerguelensis population was observed, as compared with surrounding waters.
Apalachee High School: The Last Real High School in America “You Don't Go to Apalachee, You Belong to It”
Authors: Brigham Nancy , Parker Caroline E. , Morocco Catherine Cobb , Zigmond Naomi
Published: September 2006

Located in the Florida panhandle, Apalachee High School has a student population of 1,894 students, 13% of whom have identified disabilities. The school has a highly experienced teaching staff and a special education faculty that provides acknowledged leadership in the school. Apalachee includes students with disabilities in all aspects of school life and sustains a high level of community involvement in students' success. The graphic metaphor used to represent Apalachee's approach is a set of globes and pathways that represent the academic programs and the support structures that students use to progress within and between programs. Three student case studies help to illustrate how the “pathways” respond to students with disabilities at different points on a continuum of academic and social needs and abilities. Four‐year transcripts for 39 students reflect the range of opportunities and supports (pathways) that characterize Apalachee and are illustrated by the three students we shadowed.
What Makes a High School a Good High School for Students with Disabilities
Authors: Brigharm Nancy , Morocco Catherine Cobb , Clay Karen , Zigmond Naomi
Published: September 2006

This article summarizes the findings and themes from the three high schools we studied. All three schools engaged in five schoolwide strategies for educating students with disabilities. They provided a broad array of academic courses and program options; provided schoolwide support structures that could be combined and customized to the needs and strengths of individual students; worked intentionally to connect students to the school and build their motivation to succeed; created a connected and caring adult community to serve students' academic and social/personal needs; and developed responsive leaders who managed the tensions inherent in the commitment to prepare students with disabilities to be successful in their lives beyond school. The article also reviews the different ways these three school instantiated these strategies. We describe the “theory of action” that integrates the five schoolwide strategies into a synergistic approach in each school and explore implications of the Good High Schools study for practice and for future research.
Tribological Properties of Polycrystalline Ti3SiC2and Al2O3‐Reinforced Ti3SiC2Composites
Authors: Hu Chunfeng , Zhou Yanchun , Bao Yiwang , Wan Detian
Published: September 2006

Tribological properties of Ti3SiC2and Al2O3‐reinforced Ti3SiC2composites (10 and 20 vol% Al2O3) were investigated by using an AISI‐52100 bearing steel ball dryly sliding on a linear reciprocating athletic specimen. The friction coefficients were found varying only in a range of 0.1 under the applied loads (2.5, 5, and 10 N), and the wear rates of the composites decreased with increasing Al2O3content. The enhanced wear resistance is mainly attributed to the hard Al2O3particles nail the surrounding soft matrix and decentrale the shear stresses under the sliding ball to reduce the wear losses.
Toward a better understanding of the pathophysiology of OCD SSRI responders: QEEG source localization
Authors: Bolwig T. G. , Hansen E. S. , Hansen A. , Merkin H. , Prichep L. S.
Published: September 2006

Objective:  To demonstrate the utility of three‐dimensional source localization of the scalp‐recorded electroencephalogram (EEG) for the identification of the most probable underlying brain dysfunction in patients with obsessive–compulsive disorder (OCD).

Method:  Eyes‐closed resting EEG data was recorded from the scalp locations of the International 10/20 System. Variable resolution electromagnetic tomography (VARETA) was applied to artifact‐free EEG data. This mathematical algorithm estimates the source generators of EEG recorded from the scalp.

Results:  An excess in the alpha range was found with sources in the corpus striatum, in the orbito‐frontal and temporo‐frontal regions in untreated OCD patients. This abnormality was seen to decrease following successful treatment with paroxetine.

Conclusion:  The VARETA findings of an activation/deactivation pattern in cortical and subcortical structures in paroxetine‐responsive patients are in good accordance with data obtained in previously published positron emission tomography studies related to current hypotheses of a thalamo‐striatal‐frontal feedback loop being relevant for understanding the pathophysiology of OCD.
Relationship between IL‐1A polymorphisms and gingival overgrowth in renal transplant recipients receiving Cyclosporin A
Authors: Bostanci Nagihan , Ilgenli Tunç , Pirhan Demet Can , Clarke Fiona M. , Marcenes Wagner , Atilla Gül , Hughes Francis J. , McKay Ian J.
Published: September 2006

Aim: Levels of interleukin‐1α (IL‐1α) are elevated in periodontal inflammation. IL‐1A gene polymorphisms are associated with inflammatory diseases. This study aimed to investigate IL‐1A gene polymorphism in Cyclosporin A (CsA)‐treated renal transplant patients and investigate the association between this polymorphism and gingival crevicular fluid (GCF) levels of several cytokines.

Materials and Methods: Fifty‐one renal transplant patients on CsA treatment (25 with and 26 without gingival overgrowth) and 29 healthy controls were recruited for the study. Demographic, pharmacological and periodontal parameters were recorded and gingival overgrowth was assessed.

Results: Multiple regression analysis showed that genotype was significantly associated with gingival overgrowth (p=0.02). Carriage of the IL‐1A (−889) T allele was strongly protective [95% confidence interval (CI): 0.046–0.77], although not significantly associated with IL‐1α protein levels in GCF. IL‐1α, IL‐1β and IL‐8, but not IL‐6, were detected in GCF of CsA‐treated patients, but none of them was significantly associated with gingival overgrowth.

Conclusions: This study is the first to associate a gene polymorphism as a risk factor for CsA‐induced gingival overgrowth in renal transplant patients, demonstrating that IL‐1A polymorphism might alter individual susceptibility to CsA. However, there was no association between GCF cytokine levels and the presence of gingival overgrowth or patient IL‐1A genotype.
CARD15 gene variants in aggressive periodontitis
Authors: Noack B. , Görgens H. , Hoffmann T. , Schackert H. K.
Published: September 2006

Objective: The CARD15 gene encodes a protein that acts as an intracellular receptor of bacterial products, thus playing an important role in the innate immune response. Recently, CARD15 gene variants have been identified as a cause of increased susceptibility to Crohn's disease. The present study aimed to examine a potential association of CARD15 gene variants with aggressive periodontitis susceptibility.

Material and Methods: The three main known CARD15 gene variants (p.R702W, p.G908R, and p.L1007fsX1008) were analysed by direct sequencing of exon 4, 8, and 11 of the gene in a total of 86 generalized aggressive periodontitis patients in comparison with 67 healthy controls.

Results: The mutant allele frequencies of the CARD15 variants were low in the generalized aggressive periodontitis group as well as in the control group and not significantly different (R702W: 3.5% versus 5.2%; G908R: 1.7% versus 1.5%; L1007fsX1008: 5.2% versus 4.5%). Two rare variants (A755V and R791Q), previously described only in patients with other inflammatory diseases, were observed in three patients having aggressive periodontitis but not in controls.

Conclusions: Unlike in Crohn's disease, our results did not show an association between the three main CARD15 mutations and aggressive periodontitis. The role of rare variants remains unclear.
BREAKING DOWN BUSINESS VALUATION: THE USE OF COURT‐APPOINTED BUSINESS APPRAISERS IN DIVORCE ACTIONS*
Authors: Tumminio Donna
Published: September 2006

This Note advocates for greater reliance on court‐appointed business appraisers in divorce proceedings. After exploring the history of court‐appointed experts in American jurisprudence and addressing the specific problems that arise when valuing a business, this Note demonstrates how neutral business appraisers can assist courts in assessing a highly technical matter while simultaneously providing both courts and parties with an accurate, reliable source of information. The Note further provides suggestions for when the appointment of a neutral appraiser may be beneficial. The second section of this Note addresses technical matters that the court must deal with in selecting a reliable expert, including where the court derives its power to appoint a neutral expert, what standards the court should use in appointing the expert, and who should pay the cost of the expert's appointment.
Utilizing a modified impedance analogy on sound propagation past a hard, curved, rough surface
Authors: Chambers James P. , Berthelot Yves H.
Published: September 2006

The prediction of sound propagation past a curved, rigid, rough surface can be improved by utilizing a modified surface admittance that is calculated by replacing the standard roughness parameter, ϵ, with a complex roughness parameter. The inclusion of a complex roughness, ϵ, accounts for the attenuation of the boundary wave with distance by incoherent scattering. This analogy has been successfully used to predict the sound field behind a rough, curved, rigid surface at several frequencies, by computing the creeping wave series with a best-fit surface parameter, q=i(kl)β=(kl)(kϵ).
Analysis of Sabine and Eyring equations and their application to concert hall audience and chair absorption
Authors: Beranek Leo L.
Published: September 2006

Historically, two equations have been used for predicting reverberation times, Sabine and Eyring. A precise means is presented for determining Eyring absorption coefficients αeyring when the Sabine coefficients αsabine are known, and vice versa. Thus, either formula can be used provided the absorption coefficients for the Sabine formula are allowed to exceed 1.0. The Sabine formula is not an approximation to the Eyring equation and is not a shortcoming. Given low reverberation times, the ratio of αsabine to αeyring may become greater than 2.0. It is vital that, for correct prediction of reverberation times, the absorption coefficients used in either formula must have been determined in spaces similar in size and shape, with similar locations of high absorption (audience) areas, and with similar reverberation times. For concert halls, it is found that, when the audience area (fully occupied) and midfrequency reverberation time are postulated, the hall volume is directly proportional to the audience absorption coefficient. Approximately 6% greater room volumes are needed when choosing nonrectangular versus classical-rectangular shaped halls and approximately 10% greater volumes when choosing heavily upholstered versus medium upholstered chairs. Determinations of audience sound absorption coefficients are presented, based on published acoustical and architectural data for 20 halls.
Estimated detection distance of a baiji’s (Chinese river dolphin, Lipotes vexillifer) whistles using a passive acoustic survey method
Authors: Wang Kexiong , Wang Ding , Akamatsu Tomonari , Fujita Kaoru , Shiraki Rika
Published: September 2006

Source levels and phonation intervals of whistles produced by a free-ranging baiji (Chinese river dolphin) were measured in the seminatural reserve of Shishou in Hubei, China. A total of 43 whistles were recorded over 12 recording sessions. The mean dominant frequency (the frequency at the highest energy) was 5.7kHz (s.d.=0.67). The calculated source level was 143.2dB rms re 1μPa (s.d.=5.8). Most phonation intervals were shorter than 460s, and the average interval was 205s (s.d.=254). Theoretical detection range of baiji’s whistle was 6600m at the present study site, but it could reduce a couple of hundred meters in practical noisy situation in the Yangtze River. Sporadic phonation (205s interval on average) with relatively faint signal of baiji was considered to be difficult to be detected by a towing hydrophone system. Stationed monitoring or slow speed towing of hydrophones along the river current is recommended.
Feeding behavior of wild dugongs monitored by a passive acoustical method
Authors: Tsutsumi Chika , Ichikawa Kotaro , Arai Nobuaki , Akamatsu Tomonari , Shinke Tomio , Hara Takeshi , Adulyanukosol Kanjana
Published: September 2006

Little is known about feeding behavior of wild dugongs (Dugong dugon) because direct measurements of feeding events in the water were scarcely feasible. In this study, the authors achieved the first successful feeding sound monitoring in a seagrass area using a full-band underwater recording system (called automatic underwater sound monitoring system for dugong: AUSOMS-D). In total, 175 feeding sounds were identified in 205h of recording. Feeding sounds were only detected at night, implying diurnal differences in the feeding behavior of the studied dugong population. Differences in periodicity of feeding sounds suggested that two or more individuals were in the acoustically observable area. Furthermore, a feeding position monitored by two AUSOMS-Ds was used to calculate source levels of dugong feeding sounds. Assuming spherical propagation, source levels were measured between 70.6 and 79.0dB rms re 1μPa∕Hz.
An experimental investigation of guided wave propagation in corrugated plates showing stop bands and pass bands
Authors: Kundu Tribikram , Banerjee Sourav , Jata Kumar V.
Published: September 2006

Nonplanar surfaces are often encountered in engineering structures. In aerospace structures, periodically corrugated boundaries are formed by friction-stir-welding. In civil engineering structures, rebars used in reinforced concrete beams and slabs have periodic surface. Periodic structures are also being used to create desired acoustic band gaps. For health monitoring of these structures, a good understanding of the elastic wave propagation through such periodic structures is necessary. Although a number of research papers on the wave propagation in periodic structures are available in the literature, no one experimentally investigated the guided wave propagation through plates with periodic boundaries and compared the experimental results with theoretical predictions as done in this paper. The experimental results clearly show that elastic waves can propagate through the corrugated plate (waveguide) for certain frequencies called “pass bands,” and find it difficult to propagate for some other frequencies called “stop bands.” Stop bands are found to increase with the degree of corrugation. Experimental results are compared with the theoretical predictions, and good matching is observed for plates with small degree of corrugation. Only two parameters—the depth of corrugation and the wavelength of the periodicity—are sufficient for modeling the elastic wave propagation in slightly corrugated plates.
The Pekeris waveguide revisited
Authors: Tolstoy Ivan
Published: September 2006

The traditional Pekeris treatment of the shallow water acoustic waveguide is marred by a seeming paradox: The so-called nonorthogonality of the propagation modes. This anomaly is due to the use of mistaken orthogonality criteria, and is easily exorcised by the use of normal coordinate theory (which leads to the correct orthonormality conditions for any linear conservative system).
Experimental characterization of fatigue damage in a nickel-base superalloy using nonlinear ultrasonic waves
Authors: Kim Jin-Yeon , Jacobs Laurence J. , Qu Jianmin , Littles Jerrol W.
Published: September 2006

This research develops a robust experimental procedure to track the evolution of fatigue damage in a nickel-base superalloy with the acoustic nonlinearity parameter, β, and demonstrates its effectiveness by making repeatable measurements of β in multiple specimens, subjected to both high- and low-cycle fatigue. The measurement procedure developed in this research is robust in that it is based on conventional piezoelectric contact transducers, which are readily available off the shelf, and it offers the potential for field applications. In addition, the measurement procedure enables the user to isolate sample nonlinearity from measurement system nonlinearity. The experimental results show that there is a significant increase in β linked to the high plasticity of low-cycle fatigue, and illustrate how these nonlinear ultrasonic measurements quantitatively characterize the damage state of a specimen in the early stages of fatigue. The high-cycle fatigue results are less definitive (the increase in β is not as substantial) due to increased uncertainties involved in the high-cycle fatigue tests, but still show a clear relationship between β and remaining fatigue life. One application of the measured β versus fatigue-life data is to potentially serve as a master curve for life prediction based on nonlinear ultrasonic measurements.
Internal wave effects on the ambient noise notch in the East China Sea: Model/data comparison
Authors: Rouseff Daniel , Tang Dajun
Published: September 2006

The vertical directivity pattern of the ambient noise field observed in shallow water is typically anisotropic with a trough in the horizontal. This trough, often called the ambient noise notch, develops because downward refraction steepens all rays emanating from near the sea surface. Variability in the environment has the potential to redistribute the noise into shallower angles and thereby fill the notch. In the present work, a model for the width and depth of the ambient noise notch is developed. Transport theory for acoustic propagation is combined with a shallow water internal wave model to predict the average output of a beamformer. Ambient noise data from the East China Sea are analyzed in the 1-to-5-kHz band. Good agreement between the model and the data for both the width and depth of the ambient noise notch is obtained at multiple frequencies, suggesting that internal wave effects are significant.