bluuebunny/crossref_metadata_2025 huggingface dataset:
Intrasynaptosomal Sequestration of [3H]Amphetamine and [3H]Methylenedioxyamphetamine: Characterization Suggests the Presence of a Factor Responsible for Maintaining Sequestration
Authors: Zaczek Robert , Culp Steven , De Souza Errol B.
Published: December 2006

Abstract: We examined the incorporation of [3H]methylenedioxyamphetamine ([3H]MDA) and [3H]amphetamine into rat brain synaptosomes. Saturation studies, using increasing concentrations of nonradioactive ligand, revealed that [3H]‐MDA interacted with two saturable sites that were sensitive to boiling of the tissue. Eadee‐Scatchard plots of [3H]MDA saturation data were curvilinear; nonlinear curve‐fitting analysis of these data suggested the presence of high‐ and low‐affinity [3H]MDA sites of association: KD high = 295 nM, Bmax high = 32 pmol/mg of protein; KD low = 45 μM, Bmax low = 5.2 nmol/mg of protein. Association of [3H]MDA to the low‐affinity site was dependent on the presence of isotonic sucrose in the incubation medium. The high capacities of these sites argue against a bimolecular interaction of [3H]MDA with monovalent protein binding sites. [3H]MDA incorporation was reduced under conditions that disrupt the integrity of plasma membranes, such as sonication, incubation in hypotonic media, and incubation in the presence of the detergent digitonin. These data indicate that [3H]MDA incorporation into synaptosomes may represent an internalization and sequestration phenomenon. [3H]MDA incorporation was also reduced by preincubation of the synaptosomal preparation at 37°C or in hypotonic buffer at 4°C, a result suggesting that this sequestration is maintained by an intrasynaptosomal component that is lost under the preincubation conditions described above. [3H]MDA incorporation was pH dependent (maximal at pH 7.5) and temperature sensitive (maximal incorporation occurred at 21°C and was substantially reduced at 37°C). [3H]Amphetamine was also incorporated into synaptosomes, and this incorporation was sensitive to the same physical manipulations of the tissue preparation as [3H]MDA incorporation. The synaptosomal sequestration of both [3H]MDA and [3H]amphetamine was inhibited by permeant cations, such as sodium and potassium, a result suggesting that the proposed intrasynaptosomal component that maintains the sequestration is anionic. Preliminary pharmacological profiles of [3H]MDA and [3H]amphetamine sequestration were identical. The rank order of inhibitor potencies for the incorporation of both ligands was desipramine > amphetamine > MDA > methylphenidate. This order of potency does not correspond to the lipophilicity of the test drugs. The synaptosomal incorporation and sequestration of [3H]MDA, [3H]methylenedioxymethamphetamine, and [3H]amphetamine described in the present report may be important in the molecular mechanism of action of monoamine release induced by the amphetamines.
Selective Complexing of Acetylcholinesterase in Brain by Intravenously Administered Monoclonal Antibody
Authors: Brimijoin Stephen , Balm Michael , Hammond Pamela , Lennon Vanda A.
Published: December 2006

Abstract: Rats injected intravenously with monoclonal antibodies reactive with brain acetylcholinesterase (AChE) developed a prolonged depression of plasma AChE without changes in butyrylcholinesterase, lactic acid dehydrogenase, or hematocrit. One antibody, ZR1, accumulated in the brain and spinal cord. Within 3 days of injection, ZR1 bound to most of the AChE in cerebral cortex and certain other regions of the CNS. Examination of the molecular forms of cortical AChE showed that antibody binding in vivo was selective for 10S AChE, whereas 4S AChE remained free. In vitro, however, ZRI bound equally to solubilized 4S and 10S forms. These data provide direct evidence for the compartmentalization of different AChE forms in the CNS, 10S being mainly extracellular and 4S apparently intracellular. Development of a striking and persistent bilateral ptosis within hours of injection suggests that AChE in the autonomic nervous system is also accessible to antibodies and, furthermore, is the site of an immunopathological lesion. This novel model of cholinergic autoimmunity may have relevance for human neurological disorders of unknown etiology.
Lactose‐ and Heparin‐Inhibitable Agglutinin from Human Fetal Brain
Authors: Mandal S. , Mahajan R. G.
Published: December 2006

Abstract: An agglutinin activity which was sensitive to lactose and heparin was estimated during prenatal brain development. The agglutinin showed higher specific activities in cerebral cortex and midbrain. There was an increase in lectin specific activity in all the brain regions with development. In addition to brain, other fetal organs also showed the presence of developmentally regulated agglutinin. Cerebral cortical agglutinin was purified by Sepharose CL‐6B gel filtration and asialofetuin‐ and heparin‐Sepharose affinity chromatography. Purified agglutinin was strongly inhibited by lactose, asialofetuin, and heparin. It showed no requirement for divalent cations and was maximally active at pH 8.0. Electrophoretic characterization showed the aggregate nature of the agglutinin, and sodium dodecyl sulfate‐polyacrylamide gel electrophoresis gave subunit molecular weights of 58,000, 45,000, and 24,000.
Modulation of 5‐Hydroxytryptamine1A Receptor Density by Nonhydrolyzable GTP Analogues
Authors: Harrington Melissa A. , Peroutka Stephen J.
Published: December 2006

Abstract: Co‐incubation of rat cortical membranes with 10‐4M GTP results in a competitive inhibition of 5‐hydroxytryptamine1A (5‐HT1A) receptor binding sites labeled by [3H]8‐hydroxy‐2‐(di‐n‐propylamino)tetralin ([3H]8‐OH‐DPAT). Preincubation of cortical membranes with 10‐4M GTP does not significantly change either KD or Bmax values, indicating that the effect of GTP is reversible. By contrast, GTPγS and 5′‐guanylylimidodiphosphate (GppNHp) are nonhydrolyzable analogues of GTP which lengthen the time course of guanine nucleotide activation of guanine nucleotide binding proteins (G proteins) and thereby alter G protein‐receptor interactions. These nonhydrolyzable GTP analogues were used to characterize the effects of persistent alterations in G proteins on [3H]8‐OH‐DPAT binding to 5‐HT1A receptors. Co‐incubation of rat cortical membranes with either 10‐4M GTPγS or GppNHp results in a decrease in both the affinity and apparent density of 5‐HT1A binding sites. Co‐incubation with the nonhydrolyzable nucleotides reduces the affinity of [3H]8‐OH‐DPAT binding by 65‐70% and lowers the density of the binding site by 53‐61%. Similarly, preincubation of membranes with a 10‐4M concentration of either GTPγS or GppNHp significantly increases the KD value and reduces the Bmax value of [3H]8‐OH‐DPAT binding. These results indicate that GTPγS and GppNHp induce persistent changes in 5‐HT1A receptor‐G protein interactions that are reflected as a decrease in the density of binding sites labeled by [3H]8‐OH‐DPAT.
Specific Binding of Insulin to Membranes from Dendrodendritic Synaptosomes of Rat Olfactory Bulb
Authors: Matsumoto Hajime , Rhoads Dennis E.
Published: December 2006

Abstract: The external plexiform layer of the olfactory bulb is among the brain regions where insulin receptors are most abundant. In vitro binding of porcine 125I‐insulin to membranes of dendrodendritic synaptosomes isolated from adult rat olfactory bulbs was studied to test the hypothesis that dendrodendritic synapses are major insulin‐receptive sites in the external plexiform layer of olfactory bulbs. Of the specific insulin binding sites present in a total particulate fraction from the olfactory bulbs, approximately half were recovered in the dendrodendritic synaptosome fraction. The only other subcellular fraction to which substantial insulin binding was observed was the conventional (axodendritic/axosomatic) synaptosome fraction. Analysis of equilibrium binding of insulin to dendrodendritic synaptosomal membranes, at total insulin concentrations of 0.5‐1,000 nM, revealed binding site heterogeneity consistent with a two‐site model for insulin binding to a high‐affinity (KD= 6 nM), low‐capacity (Bmax= 110 fmol/mg of protein) site and a low‐affinity (KD= 190 nM), high‐capacity (Bmax= 570 fmol/mg of protein) site. The results indicate that the intense labeling of the external plexiform layer of the olfactory bulb in autoradiographic studies of insulin binding can be attributed to insulin receptors on dendrodendritic synaptic membranes in this region.
Localization and Transport of N‐Acetylaspartylglutamate in Cells of Whole Murine Brain in Primary Culture
Authors: Cassidy Martha , Neale Joseph H.
Published: December 2006

Abstract: N‐Acetylaspartylglutamate (NAAG) is the most abundant neuropeptide in the mammalian nervous system. Considerable data support the hypothesis that NAAG is synaptically released in a manner consistent with neurotransmission. Primary murine brain cultures containing neurons and glia expressed 1.2‐3.5 nmol of NAAG/mg of protein. In contrast to conclusions drawn from immunohistochemistry, pure glial cultures also expressed high levels of NAAG (0.6‐2.11 nmol/mg of protein). These data suggest that although a subpopulation of neurons contains very high NAAG levels, micromolar concentrations of the peptide also are present in glia. Both culture types demonstrated robust extracellular peptidase activity when incubated with NAAG, as well as peptide transport. Uptake of [3H]NAAG was both temperature and sodium dependent, yet relatively insensitive to the presence of extracellular glutamate. These results indicate that synaptically released NAAG, as well as that which may be released from glia, is removed from the extracellular space by direct uptake as well as the robust enzymatic degradation of the peptide. A kinetic analysis of this NAAG transport (estimated Km= 1.8 μM) suggests a high‐affinity NAAG transport system. The balance of the two processes of direct peptide uptake and peptide hydrolysis would markedly influence the sequence of receptor‐mediated events that follow NAAG release.
Isoform‐Specific Effects of Transforming Growth Factors‐β on Degeneration of Primary Neuronal Cultures Induced by Cytotoxic Hypoxia or Glutamate
Authors: Prehn Jochen H. M. , Peruchc Barbara , Unsicker Klaus , Krieglstein Josef
Published: December 2006

Abstract: The transforming growth factors‐β (TGFs‐β) are multifunctional peptide‐growth factors that have been localized in neuronal and glial cells of the C'NS of mice. rats, and chick embryos. We tested the TGF‐β isoforms 1. 2. and 3 for their protective ctlects against neuronal degeneration caused by cytotoxic hypoxia or by the excitatory amino acid i ‐glutamate. A cytotoxic hypoxia was induced in cultured chick embryo telencephalic neurons by adding I m.l/ sodium cyanide to the culture medium tor a period of 30min. I reatment with TGF‐81 (1‐30 ng/ml) led to a statistically significant increase in cell viability, neuronal ATP levels. and protein content of the cultures assessed 72 h after the toxic insult. TGF‐33 was able to reduce the cyanide‐induced neuronal damage at concentrations of 0.3 and 1 ng/ ml. whereas TGF‐33, only showed neuroprotective activity at concentrations of 30 and 50 ng/ml. Both pre‐ and posttreatment with TGF‐31, also prevented the degeneration of cultured chick embryo telencephalic neurons that had been exposed to I mM L‐glutamate in a buffered salt solution for a period of 60 min. Furthermore, TGF‐β1 (0.3‐3 ng/ml). and to a lesser extent TGF‐β3 (0.1‐1 ng/ml). significantly reduced excitotoxic injury of cultured neurons from rat cerebral cortex that had been exposed to serum‐free culture medium supplemented with 1 m.M L‐glutamate. These results demonstrate that the TGFs‐β are able to prevent the degeneration of primary neuronal cultures, which was caused by energy depletion and activation of glutamate receptors, in an isoform‐specific manner.
Ethanol‐Induced Aspartate and Taurine Release from Primary Astrocyte Cultures
Authors: Kimelberg H. K. , Cheema M. , O'Connor E. R. , Tong H. , Goderie S. K. , Rossman P. A.
Published: December 2006

Abstract: Exposure of primary astrocyte cultures to isosmo‐tic ethanol from 10‐100 mA/ led to both swelling of the cells and release of [3H]taurine and r[3H]aspartate. Exposure to hyperosmotic ethanol, in the same concentration range. caused neither swelling nor release. Release was inhibited by the anion transport blocker L‐644,711, already shown to inhibit amino acid release evoked by hyposmotic or high‐potassium medium, conditions that also cause astrocytic swelling. Ethanol‐induced release generally showed a decline in response to successive exposures to ethanol, and release was not dependent on extracellular calcium. Thus, the characteristics of swelling‐induced release of amino acids by isosmotic ethanol seem to correspond to those of swelling‐induced release from astrocytes due to exposure to hypotonic or high‐K+ media. We discuss whether such effects may contribute to CNS damage after head injury and stroke.
YM‐09151‐2 but Not l‐Sulpiride Induces Transient Dopamine Release in Rat Striatum via a Tetrodotoxin‐Insensitive Mechanism
Authors: Tomiyama Katsunori , Noguchi Momoyo , Koshikawa Noriaki , Kobayashi Masafumi
Published: December 2006

Abstract: The effects of the selective dopamine D2 receptor antagonists YM‐09151‐2 and l‐sulpiride on the in vivo release of dopamine (DA), l‐3,4‐dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in rat striatum were investigated. The drugs were injected into the striatum through a microinjection needle attached to a dialysis probe. YM‐09151‐2 (0.1 or 1.0 μg/0.5 μl) injected into the striatum produced a dramatic rapid‐onset transient increase in striatal DA release in a dose‐dependent manner. However, the DA increase induced by l‐sulpiride (15 or 75 ng/0.5 μl) was small and of slower onset. An increase of DOPAC levels by YM‐09151‐2 was biphasic: The first peak occurred at 40 min, followed by a delayed‐onset gradual increase. Slower‐onset gradual increases were also found in DOPAC levels after l‐sulpiride injection and in HVA levels after injections of both YM‐09151‐2 and l‐sulpiride. The infusion of tetrodotoxin (TTX; 2 μM) revealed two different types of DA release mechanisms: The rapid‐onset transient DA release induced by YM‐09151‐2 was TTX insensitive, whereas the slower‐onset DA release induced by l‐sulpiride was TTX sensitive. Moreover, the rapid‐onset transient DA release was Ca2+ independent and was not affected by pre‐treatment with l‐sulpiride or nomifensine. Therefore, it is concluded that YM‐09151‐2 injected into the striatum produced a transient striatal DA release that is independent of D2 receptors and the action potential.
(R,S)‐α‐Amino‐3‐Hydroxy‐5‐Methylisoxazole‐4‐Propionic Acid (AMPA) Receptors Mediate a Calcium‐Dependent Inhibition of the Metabotropic Glutamate Receptor‐Stimulated Formation of Inositol 1,4,5‐Trisphosphate
Authors: Lonart Gyorgy , Alagarsamy Sudarkodi , Johnson Kenneth M.
Published: December 2006

Abstract: l‐Glutamate (3‐1,000 μM) and (1S,3R)‐l‐aminocyclopentane‐1,3‐dicarboxylic acid (1S.3R‐ACPD; 10‐1,000 μM), a selective agonist for the metabotropic glutamate receptor, stimulated the formation of inositol 1,4,5‐trisphosphate in a concentration‐dependent manner. l‐Glutamate was half as efficacious as 1S,3R‐ACPD. N‐methyl‐d‐aspartate (nMDA; 1 nM to 1 mM) did not significantly influence the response to a maximally effective concentration of 1S,3R‐ACPD (100 μM). On the other hand, coapplication of (R,S)‐α‐amino‐3‐hydroxy‐5‐methylisoxa‐zole‐4‐propionic acid (AMPA; 1‐300 nM) produced a concentration‐ and time‐dependent inhibition of the 1S,3R‐ACPD effect, with a maximal inhibition (97%) at 100 nM. Ten micromolar 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione. an antagonist of the AMPA receptor, blocked the inhibitory effect of AMPA. Reduced extracellular calcium concentration, as well as 10 μM nimodipine, an l‐type calcium channel antagonist, inhibited the AMPA influence on the 1S,3R‐ACPD response. W‐7, a calcium/calmodulin antagonist, prevented the inhibition by AMPA. whereas H‐7. an inhibitor of protein kinase C, had no effect. These data suggest that activation of AMPA receptors has an inhibitory influence on inositol 1,4,5‐trisphosphate formation mediated by stimulation of the metabotropic glutamate receptor. The mechanism of action involves calcium influx through l‐type calcium channels and possible activation of calcium/calmodulin‐dependent enzymes.
Methamphetamine‐Induced Dopamine Overflow and Injury to Striatal Dopamine Terminals: Attenuation by Dopamine D1 or D2 Antagonists
Authors: O'Dell Steven J. , Weihmuller Fredric B. , Marshall John F.
Published: December 2006

Abstract: Pharmacological blockade of either D1 or D2 dopamine (DA) receptors prevents damage of striatal DA terminals by repeated doses of methamphetamine (m‐AMPH). Because the substantial DA overflow produced by multiple m‐AMPH treatments appears to contribute to the subsequent injury, we have investigated the effects of blockade of D1 or D2 receptors on m‐AMPH‐induced DA efflux using in vivo microdialysis. Four treatments with m‐AMPH (4 mg/kg, s.c., 2‐h intervals) produced large increases in striatal DA overflow, with particularly marked overflow (10 times the basal values) following the fourth injection. Administered by themselves, four injections of the D1 antagonist SCH 23390 or the D2 antagonist eticlopride (0.5 mg/kg, i.p., 2‐h intervals) significantly increased striatal DA overflow. However, treatment with either SCH 23390 or eticlopride 15 min before each of four m‐AMPH injections attenuated the marked DA peak otherwise seen after the fourth m‐AMPH injection. These effects on DA overflow were related to subsequent DA depletions. Although our m‐AMPH regimen produced a 54% reduction in striatal DA tissue content 1 week later, pretreatments with either the D1 or the D2 antagonist completely prevented subsequent DA content depletions. Furthermore, the DA content of striatal tissue remaining 1 week after m‐AMPH treatment was significantly correlated with the magnitude of the cumulative DA overflow during the m‐AMPH treatment (r= ‐0.69). Thus, the extensive DA overflow seen during neurotoxic regimens of m‐AMPH appears critical to the subsequent neurotoxicity, and the neuroprotective action of DA receptor antagonists seems to result from their attenuation of stimulant‐induced DA overflow.
Characterization of Tritiated Noradrenaline Release from the Rat Preoptic Area with Microdialysis In Vivo
Authors: Fernández‐Galaz Carmen , Herbison Allan E. , Dyer Richard G.
Published: December 2006

Abstract: Present techniques are unable to provide a sensitive and accurate index of noradrenergic activity in the rat preoptic area. In this study, we have examined the brainstem A1 noradrenergic input to the preoptic area using a new technique whereby [3H]noradrenaline is preloaded into the preoptic area and release of radioactivity from this region is measured subsequently using microdialysis in vivo. Electrical stimulation of the ipsilateral A1 area for 20 min at 5, 10, and 15 Hz evoked significant increases in dialysate radioactivity that were repeatable and frequency‐dependent. After removal of calcium from the perfusion medium, basal release of radioactivity was markedly reduced and the effect of A1 stimulation abolished. Changing to a 100 mM K+ medium evoked an increase in the release of radioactivity that was sixfold greater than that seen after A1 stimulation. Separation of the dialysate with HPLC showed that 33% of the increase in measured radioactivity after A1 stimulation was directly attributable to [3H]noradrenaline and the remainder to the metabolites vanillylmandelic acid, 3,4‐dihydroxymandelic acid, and 3,4‐dihydroxyphenylglycol. In contrast, the increase in radioactivity after K+ depolarization was due almost completely to [3H]noradrenaline. Addition of 10 μM clonidine to the perfusion medium markedly reduced basal release of radioactivity, but had no effect on evoked release following A1 stimulation. Conversely, perfusion with 10 μM yohimbine had no effect on basal release, but significantly increased evoked release after A1 stimulation. These results now provide a characterization of noradrenergic activity in the preoptic area and indicate the importance of the A1 noradrenergic input to this region. The technique of measuring radioactivity with microdialysis after preloading with [3H]noradrenaline provides a relatively simple, sensitive index of noradrenergic activity in vivo with good temporal resolution.
Metamorphic Changes in Glycolipids and Myelin Proteins and 2′,3′‐Cyclic Nucleotide 3′‐Phosphohydrolase in Bullfrog and Axolotl Brains
Authors: Tamai Yoichi , Kojima Hisako , Saito Shintaro , Uchida Kikue , Kitajima Rie , Komatsu Hiroshi , Moriya Tsuneo
Published: December 2006

Abstract: The metamorphic changes in levels of glycolipids and myelin proteins and 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase (CNP) in the brains of bullfrog tadpoles, adult frogs, and axolotls were investigated, with particular emphasis on myelin maturation. The concentrations of cerebroside. sulfatide, and galactosyldiacylglycerol gradually increased from the onset of prometamorphosis throughout the active metamorphic period and then greatly increased after metamorphosis was completed. The ratio of glucocerebroside to galactocerebroside increased greatly in the prometamorphic period and then rapidly decreased to the frog level during the climax period. The fatty acid compositions of cerebroside and sulfatide showed a developmental change, with 24:1 being more predominant in the later metamorphic stage. The proportion of hydroxy fatty acids increased up to the onset of the prometamorphic stage and thereafter remained constant at ∼ 50% of the total. The CNP activity remained unchanged throughout metamorphosis at 60% that in frog myelin and increased in the adult frog. The composition of tadpole myelin proteins remained constant during metamorphosis, with large basic protein being the most abundant, and in the frog, proteolipid protein and large basic protein were present in comparable amounts. The two adult forms of axolotl, i.e., the neotenous and metamorphosed forms, exhibited almost identical myelin constituents, and CNP activity in the neotenous form amounted to one‐fifth that in the bullfrog. These results indicate that active biosynthesis of myelin marker components occurs as metamorphosis proceeds, but more pronounced changes of myelin components occur after metamorphosis is completed.
N‐methyl‐d‐Aspartic Acid Differentially Regulates Extracellular Dopamine, GABA, and Glutamate Levels in the Dorsolateral Neostriatum of the Halothane‐Anesthetized Rat: An In Vivo Microdialysis Study
Authors: Morari M. , O'Connor W. T. , Ungerstedt U. , Fuxe K.
Published: December 2006

Abstract: The effects of local perfusion with the glutamate receptor agonist NMDA and the noncompetitive NMDA receptor antagonist dizolcipine (MK‐801) on extracellular dopamine (DA), GABA, and glutamate (Glu) levels in the dorsolateral striatum were monitored using in vivo microdialysis in the halothane‐anesthetized rat. In addition, the sensitivity of both the basal and NMDA‐induced increases in levels of these neurotransmitter substances to perfusion with tetrodotoxin (TTX; 10−5 M) and a low Ca2+ concentration (0.1 mM) was studied. The results show that the local perfusion (10 min) with both the 10−3 and 10−4 M dose of NMDA increased striatal DA and GABA outflow, whereas only the (10−3 M) dose of NMDA was associated with a small and delayed increase in extracellular Glu levels. The NMDA‐induced effects were dose‐dependently counteracted by simultaneous perfusion with MK‐801 (10−6 and 10−5 M). Both the basal and NMDA (10−3 M)‐induced increase in extracellular striatal DA content was reduced in the presence of TTX and a low Ca2+ concentration, whereas both basal and NMDA‐stimulated GABA levels were unaffected by these treatments. Both the basal and NMDA‐stimulated Glu levels were enhanced following TTX treatment, whereas perfusion with a low Ca2+ concentration reduced basal Glu levels and enhanced and prolonged the NMDA‐induced stimulation. These data support the view that NMDA receptor stimulation plays a role in the regulation of extracellular DA, GABA, and Glu levels in the dorsolateral neostriatum and provide evidence for a differential effect of NMDA receptor stimulation on these three striatal neurotransmitter systems, possibly reflecting direct and indirect actions mediated via striatal NMDA receptors.
Interaction Between the Glutamine Cycle and the Uptake of Large Neutral Amino Acids in Astrocytes
Authors: Brookes Neville
Published: December 2006

Abstract: When astrocyte cultures are incubated with glutamate and ammonium, the clearance of these substrates followed by the formation and export of glutamine simulates the action of the “glutamine cycle” that is believed to function in the CNS. In the present study this process was found to increase the uptake of large neutral amino acids (LNAAs), namely, histidine, kynurenine, leucine, phenylalanine, and tryptophan, by two‐to threefold in mouse cerebral astrocytes. The enhancement of kynurenine uptake was shown to depend on the formation of glutamine and to saturate at low levels of glutamine. LNAAs transiently lowered the glutamine content of astrocytes that were incubated with glutamate and ammonium, but they did not affect net export of glutamine to the solution at normal physiological pH. However, on adjustment of the pH of the solution to 7.8, which causes a large increase in glutamine content without affecting export, kynurenine now significantly increased net glutamine export. These findings relate to proposed mechanisms of cerebral dysfunction in hyperammonemia.
Difference in the Effectiveness of Ca2+ to Evoke Catecholamine Secretion Between Adrenaline‐and Noradrenaline‐Containing Cells of Bovine Adrenal Medulla
Authors: Teraoka Hiroki , Sugawara Takeshi , Nakazato Yoshikazu
Published: December 2006

Abstract: Differential adrenaline (Ad) and noradrenaline (NA) secretions evoked by secretagogues were investigated using digitonin‐permeabilized adrenal chromaffin cells, cultured adrenal chromaffin cells, and perfused adrenal glands of the ox. In digitonin‐permeabilized cells, Ca2+ (0.8‐160 μM) caused a concentration‐dependent increase in catecholamine secretion, which was characterized by a predominance of NA over Ad secretion. Acetylcholine (10‐1,000 μM), high K+ (14‐56 μM), and bradykinin (0.1‐1,000 μM) all were confirmed to induce the release of more NA than Ad at all concentrations used. There was no apparent difference in the ratios of NA/Ad between Ca2+‐induced catecholamine secretion from digitonin‐permeabilized cells and those induced by secretagogues from cultured cells. Qualitatively the same result was obtained in the secretory responses to acetylcholine and high K+ in perfused adrenal glands. These results indicate that the effectiveness of Ca2+ for catecholamine secretion is higher in the secretory apparatus of NA cells than in that of Ad cells of the bovine adrenal medulla. This may be one of the reasons why the secretagogues cause a predominance of NA secretion over Ad secretion in the bovine adrenal medulla.
The Chronic Administration of Nicotine Induces Cytochrome P450 in Rat Brain
Authors: Anandatheerthavarada Hindupur K. , Williams Joseph F. , Wecker Lynn
Published: December 2006

Abstract: The objective of these studies was to determine whether chronic administration of nicotine altered the cytochrome P450 (P450) monooxygenase system in rat brain. Male Sprague‐Dawley rats received injections of nicotine bitartrate (1.76 mg/kg, s.c, twice daily for 10 days), and total cytochrome P450 content, the activity of N ADPH‐cytochrome c reductase, and the activities and relative abundance of P4502B1 and P4502B2 (P4502B1/2) were determined in microsomal fractions from rat brain. The content of P450 increased significantly (p < 0.02) in all brain regions examined from nicotine‐injected rats: the largest increase (208% of control) was in frontal cortex and the smallest increase (122% of control) in cerebellum. The activity of NADPH‐cytochrome c reductase was unaltered by nicotine administration. Benzyloxyresorufin O‐dealkylase (BROD) and pentoxyresorufin O‐dealkylase (PROD) activities, mediated by P4502B1/2, increased significantly (p < 0.02) following nicotine administration; the largest increase (213‐227% of control) was in frontal cortex. Western blots of microsomal proteins indicated that the increase in enzymatic activity was associated with an increase in content of P4502B1/2 immunoreactive proteins. In contrast to brain, total P450 content, activities of NADPH‐cytochrome c reductase, BROD, and PROD, and levels of P4502B1 /2 immunoreactive proteins in liver were unaffected by chronic nicotine administration. Results indicate that chronic nicotine administration regulates the expression of P4502B1/2 in brain and that at the dose schedule used this effect occurs without a demonstrable effect on the hepatic P450 monooxygenase system.
Glutamate‐Induced Neuronal Death Is Not a Programmed Cell Death in Cerebellar Culture
Authors: Dessi Frédéric , Charriaut‐Marlangue Christiane , Khrestchatisky Michel , Ben‐Ari Yezekiel
Published: December 2006

Abstract: Activation of programmed cell death has recently been suggested to be involved in the delayed neuronal death of CA1 hippocampal neurons after global ischemia based on protection offered by protein synthesis inhibitors. Here, we studied the effects of transcriptional (actinomycin D) and translational (cycloheximide and anisomycin) inhibitors on glutamate‐induced neuronal death in cerebellar granule cell cultures. The effects of aurintricarboxylic acid, an endonuclease inhibitor, were studied as well. No protection against glutamate toxicity could be observed with any of these inhibitors. We also analyzed the genomic DNA of glutamate‐treated cells on agarose gel electrophoresis. No DNA degradation could be observed after glutamate exposure. We conclude that glutamate‐induced neuronal death does not exhibit the features of apoptosis in cultured granule cells.
Age‐Dependent Impairment of Mitochondrial Function in Primate Brain
Authors: Bowling Allen C. , Mutisya Elizabeth M. , Walker Lary C. , Price Donald L. , Cork Linda C. , Beal M. Hint
Published: December 2006

Abstract: It has been hypothesized that some of the functional impairments associated with aging are the result of increasing oxidative damage to mitochondrial DNA that produces defects in oxidative phosphorylation. To test this hypothesis, we examined the enzymes that catalyze oxidative phosphorylation in crude mitochondrial preparations from frontoparietal cortex of 20 rhesus monkeys (5‐34 years old). Samples were assayed for complex I, complex II‐III, complex IV, complex V, and citrate synthase activities. When enzyme activities were corrected for citrate synthase activities (to account for variable degrees of mitochondrial enrichment), linear regression analysis demonstrated a significant negative correlation of the activities of complex I (p < 0.002) and complex IV (p < 0.03) with age but no significant change in complex II‐III or complex V activities. Relative to animals 6.9 ± 0.9 years old (n = 7), the citrate synthase‐corrected activity of complex I was reduced by 17% in animals 22.5 ± 0.9 years old (n = 6) (p < 0.05) and by 22% in animals 30.7 ± 0.9 years old (n = 7) (p < 0.01). Similar age‐related reductions in the activities of complexes I and IV were obtained when enzyme activities were corrected for complex II‐III activity. These findings show an age‐associated progressive impairment of mitochondrial complex I and complex IV activities in cerebral cortices of primates.
The N‐Methyl‐D‐Aspartate Antagonist MK‐801 Fails to Protect Dopaminergic Neurons from 1‐Methyl‐4‐ Phenylpyridinium Toxicity In Vitro
Authors: Finiels‐Marlier Francoise , Marini Ann M. , Williams Pat , Paul Steven M.
Published: December 2006

Abstract: Recent reports suggest that NMDA receptor antagonists when administered in vivo can protect dopaminergic neurons from the toxic actions of MPP+. In the present study the possible neuroprotective effects against MPP+ toxicity of the noncompetitive NMDA receptor antagonist MK‐801 was studied in primary cultures of fetal rat mesencephalic dopamine neurons. MK‐801 failed to protect dopaminergic neurons from MPP+ toxicity at concentrations that completely block NMDA‐induced toxicity of these same neurons. In contrast to work carried out in cerebellar granule cells, MPP+ toxicity of mesencephalic dopamine neurons was unaffected by preexposure to subtoxic concentrations of either NMDA or cycloheximide. Our findings suggest that the toxic effects of MPP+ on dopaminergic neurons are not mediated through a direct interaction with the NMDA subtype of glutamate receptor.
Exogenous purines induce differential responses in the proximal and distal regions of the possum sphincter of Oddi
Authors: Woods C. M. , Toouli J. , Saccone G. T. P.
Published: December 2006

1The aim of this study was to compare the effect of exogenous ATP and adenosine on spontaneous motility of the proximal and distal regions of the possum sphincter of Oddi (SO).

2ATP or adenosine (1 μm–1 mm) was applied to distal‐SO or proximal‐SO muscle rings in organ baths in the absence or presence of tetrodotoxin (TTX) or P1/P2 antagonists.

3Both ATP and adenosine altered spontaneous activity, predominantly in proximal‐SO rings.

4Exogenous ATP induced a bi‐phasic response consisting of a brief TTX‐sensitive excitatory component, and a longer‐lasting TTX‐insensitive inhibitory component.

5The excitatory ATP response likely involves P2X receptors, whereas the late inhibitory response likely involves P2Y receptors.

6Exogenous adenosine decreased spontaneous SO activity, via a TTX‐insensitive mechanism.

7Exogenous purines modulate SO motility, acting primarily in the proximal region of the SO, via neural and non‐neural mechanisms and multiple purine receptor subtypes.
From Chelating Precursor to Perovskite Oxides and Hollow Fiber Membranes
Authors: Liu S. , Liu M. , Shao Z. , Diniz da Costa J. C. , Xu Z. P.
Published: December 2006

Perovskite Ba0.5Sr0.5Co0.8Fe0.2O3‐δ (BSCF) is a promising mixed‐conducting ceramic membrane material in addition to being a good electrode catalyst for solid oxide fuel cells. In this study, BSCF powder was synthesized via a chelated water‐soluble complex method at relatively low temperatures. The combined ethylenediaminetetraacetic acid and citric acid was used for the synthesis of a complex‐based precursor, followed by thermal decomposition of the precursor at high temperatures. Thermal behavior, crystal phases, and structures of the prepared powders were characterized by thermogravimetric analysis/differential scanning calorimetry, XRD, and scanning electron microscopic (SEM) techniques, respectively. Pure and single‐phase perovskite could be obtained after sintering at a temperature higher than 800°C for 5 h. The soft precursor powder synthesized at lower temperatures, i.e., 600°C, is water insoluble and more appropriate for use as a membrane material to prepare gas‐tight tubular or hollow fiber ceramic membranes. By contrast, the hollow fibers prepared via the traditional techniques where the perovskite powder is used as the starting membrane materials display gas leakage. The fibers were characterized by SEM, XRD, and tested for air separation at ambient pressure and temperatures between 700° and 950°C. The oxygen flux measured in this work reached 3.90 mL·(min·cm2)−1 and compares favorably with any experimental values reported in the open literature.
Stress‐Driven Morphological Instabilities in Rocks, Glass, and Ceramics
Authors: Grinfeld M. A.
Published: December 2006

The purpose of this study is to further investigate the classical Gibbs analysis of the heterogeneous system “stressed crystal–melt.” It is demonstrated that each equilibrium configuration is stable with respect to a special class of variations introduced by Gibbs. This basic result is compared with the opposite result on the universal morphological instability of phase interface separating a stressed crystal with its melt. Some plausible manifestations of the instabilities implied by the Gibbs model are qualitatively discussed.
Dielectric Relaxation in Layer‐Structured SrBi2−xNdxNb2O9 Ceramics (x=0, 0.05, 0.2, 0.35)
Authors: Sun Lin , Feng Chude , Chen Lidong , Huang Shiming
Published: December 2006

SrBi2−xNdxNb2O9 (x=0, 0.05, 0.2, 0.35) ceramics were synthesized by the traditional solid‐state sintering method. X‐ray diffraction analysis showed that single‐phase‐layered perovskites were obtained for all compositions. The substitution of Nd3+ for Bi3+ induced a relaxor behavior of frequency dispersion for Nd‐doped SrBi2Nb2O9.The parameter of frequency dispersion ΔTm, which is the Tm between 1 kHz and 1 MHz, increases from 0°C for x=0 to 13°C for x=0.35, and the degree of relaxor behavior γ increases from 0.96 for x=0 to 2.02 for x=0.35. The temperature of the maximum dielectric constant Tm decreases linearly with an increase in the Nd content (x).
Two‐Stage Sintering of Alumina with Submicrometer Grain Size
Authors: Bodišová Katarína , Šajgalík Pavol , Galusek Dušan , Švančárek Peter
Published: December 2006

This work verifies the applicability of two‐stage sintering as a means of suppressing the final stage grain growth of submicrometer alumina. The first heating step should be short at a relatively high‐temperature (1400°–1450°C) in order to close porosity without significant grain growth. The second step at temperatures around 1150°C facilitates further densification with limited grain growth. Fine‐grained alumina with a relative density of 98.8% and a grain size of 0.9 μm was prepared by two‐stage sintering. A standard sintering process resulted in ceramics with identical relative density and a grain size of 1.6 μm.
Frozen Human Bone: A Microscopic Investigation
Authors: Tersigni MariaTeresa A.
Published: December 2006

ABSTRACT: The taphonomic effects of prolonged extreme cold and freezing on human bone have received little research attention. Questions of specific interest include whether previously frozen bone can be identified and whether freezing alters the structural integrity enough to prevent histological aging. There is no evidence from previous studies that freezing damages the structural integrity, and to date no research investigating the freezing process on bone microstructure has been undertaken. This research attempts to distinguish histologically previously frozen bone from nonfrozen bone by identifying patterned defects. To determine the effects of freezing in bone microstructure using light and scanning electron microscopy (SEM), several human bone sections were subjected to prolonged freezing and allowed to thaw before thin sectioning. Light microscopy failed to demonstrate statistically significant differences between frozen and nonfrozen specimens. SEM analysis revealed fractures, although these lacked pattern and did not occur systematically throughout the section. Evidence of microstructural changes caused by liquid expansion, however, was remarkable but did not alter the structural integrity of the microstructure. The results of this study suggest that freezing does not alter the process of histomorphological analysis.
Mole Guns in Turkey in 2003–2005
Authors: Yılmaz Rıza , Birincioğlu İsmail , Çakır İsmail , Üner H. Bülent , Açıkgöz Dinç , Seçkin Çetin
Published: December 2006

ABSTRACT: This study describes the frequency of mole guns in Turkey by examining the cases sent to the Council of Forensic Medicine of Turkey between 2003 and 2005. In total, 11 mole guns were examined. Mole guns are manufactured to be used as a trap against detrimental animals. Although they are not meant to be used as a firearm, they are able to cause death. Mole guns appearing in regular casework were evaluated in terms of type of the gun, number of barrels, size and caliber, rifling, design, mechanism, fitness for use, legality, and geographical distribution. Ninty‐one percent of the guns were 12 gauge. Most commonly they originate from Inner Anatolia. Mole guns are typically handmade. Some examples of injuries and deaths caused by mole guns are also offered.
Infrared Spectroscopic Imaging for Noninvasive Detection of Latent Fingerprints
Authors: Crane Nicole J. , Bartick Edward G. , Perlman Rebecca Schwartz , Huffman Scott
Published: December 2006

ABSTRACT: The capability of Fourier transform infrared (FTIR) spectroscopic imaging to provide detailed images of unprocessed latent fingerprints while also preserving important trace evidence is demonstrated. Unprocessed fingerprints were developed on various porous and nonporous substrates. Data‐processing methods used to extract the latent fingerprint ridge pattern from the background material included basic infrared spectroscopic band intensities, addition and subtraction of band intensity measurements, principal components analysis (PCA) and calculation of second derivative band intensities, as well as combinations of these various techniques. Additionally, trace evidence within the fingerprints was recovered and identified.
Visual Detection of Trace Nitroaromatic Explosive Residue Using Photoluminescent Metallole‐Containing Polymers
Authors: Toal Sarah J. , Sanchez Jason C. , Dugan Regina E. , Trogler William C.
Published: December 2006

ABSTRACT: The detection of trace explosives is important for forensic, military, and homeland security applications. Detection of widely used nitroaromatic explosives (trinitrotoluene [TNT], 2,4‐dinitrotoluene [DNT], picric acid [PA]) was carried out using photoluminescent metallole‐containing polymers. The method of detection is through the quenching of fluorescence of thin films of the polymer, prepared by spray coating organic solutions of the polymer, by the explosive analyte. Visual quenching of luminescence (λem≈400–510 nm) in the presence of the explosive is seen immediately upon illumination with near‐UV light (λex=360 nm). Detection limits were observed to be as low as 5 ng for TNT, 20 ng for DNT, and 5 ng for PA. In addition, experiments with normal production line explosives and their components show that this technology is also able to detect composition B, Pyrodex®, and nitromethane. This method offers a convenient and sensitive method of detection of trace nitroaromatic explosive residue.
Pen Guns in Turkey
Authors: Yılmaz Rıza , Birincioğlu İsmail , Bülent Üner H. , Günce Elif
Published: December 2006

ABSTRACT: This study describes the frequency and type of pen guns in Turkey by examining the cases sent to the Council of Forensic Medicine of Turkey between 2000 and 2004. In total, 32 cases and 61 pen guns were examined. These guns were evaluated in respect of the type of the gun, size and caliber, rifling, design, mechanism, fitness for use, legality, and geographical distribution. Fifty‐nine percent of the guns were 22‐gauge. Most commonly, they originate from South Eastern Anatolia. It is suggested that the guns are handmade.
Age Estimation by Pulp/Tooth Ratio in Canines by Peri‐Apical X‐Rays
Authors: Cameriere Roberto , Ferrante Luigi , Belcastro Maria Giovanna , Bonfiglioli Benedetta , Rastelli Elisa , Cingolani Mariano
Published: December 2006

ABSTRACT: Estimation of age in individuals has received considerable attention in forensic science, in which it is a widely used method for individual identification, together with paleo‐demographic analyses to establish mortality patterns in past populations. The present investigation, which is a continuation of a previously published pilot study, was conducted to examine the possible application of the pulp/tooth area ratio by peri‐apical images as an indicator of age at death. A total of 200 peri‐apical X‐rays of upper and lower canines were assembled from 57 male and 43 female skeletons of Caucasian origin, aged between 20 and 79 years. They belong to the Frassetto osteological collection of Sassari (Sardinia) and are housed in the Museum of Anthropology, Department of Experimental and Evolutionistic Biology, University of Bologna. For each skeleton, dental maturity was evaluated by measuring the pulp/tooth area ratio on upper (x1) and lower (x2) canines. Very good agreement was found between intraobserver measurements. Statistical analysis was performed in order to obtain multiple regression formulae for dental age calculation, with chronological age as dependent variable, and gender, and upper and lower canines as independent variables. Stepwise regression analysis showed that gender did not contribute significantly to the fit (p=0.881) whereas variables x1 and x2 and the first‐order interaction between them did. These two variables explained 92.5% of variations in estimated chronological age and the residual standard error was 4.06 years. Lastly, two simple linear regression equations were obtained for age estimation using canines from the maxilla and mandible separately. Both models explained 86% of variations in estimated chronological age and allowed an age‐at‐death estimate with a residual standard error of about 5.4 years.
Southwest China Han Population Data for Nine Y‐STR Loci by Multiplex Polymerase Chain Reaction
Authors: Shi Meisen , Li Yingbi , Tang Jianpin , Zhang Haijun , Hou Yiping
Published: December 2006

POPULATION: One hundred and twenty unrelated Han ethnic individuals from Chengdu, southwest China.
Genotype Profile for Fifteen Tetranucleotide Repeat Loci in Two Tibeto‐Burman Speaking Tribal Populations of Arunachal Pradesh, India
Authors: Krithika S. , Trivedi R. , Kashyap V. K. , Vasulu T. S.
Published: December 2006

POPULATION: Two Tibeto‐Burman‐speaking Adi tribal populations of Arunachal Pradesh, India, Adi Pasi (n=121) from Upper Siang district, and Adi Minyong (n=33) from East Siang district were analyzed for polymorphisms at 15 microsatellite loci. The populations belong to Mongoloid ethnicity and are of special significance in genetic studies due to their small population size, relative isolation in remote hilly areas, and traditional subsistence patterns.