bluuebunny/crossref_metadata_2025 huggingface dataset:
Origins of Police Officer Stress before and after 9/11
Authors: Stevens Dennis J.
Published: August 2004

This article examines the origins of stress amongst police officers after the destruction of the World Trade Centers and compares those responses with a similar group of officers prior to this tragic event. The previous sample consisted of 415 officers and the current sample consists of 310 Boston officers. The survey used and the demographics of both samples were similar. Results show that the ‘before’ 9/11 group felt that harming or killing an innocent person was at the top of their critical incident list as compared with the ‘after’ 9/11 group who selected hate groups/terrorists. The ‘before’ group's most salient outcome led to the abuse of their own children or a lack of parental affection. The ‘after’ group's most salient outcome led to a reduction in self-respect owing, unexpectedly, to structural policy changes linked in part to FBI deception as opposed to job experiences or occupational risks. Recommendations were suggested to enhance police organisational strategies. More research should be conducted on the processes of police organisational change.
Vigilance or Vigilantes: The Paulsgrove Riots and Policing Paedophiles in the Community Part 1: The Long Slow Fuse
Authors: Williams Andy , Thompson Bill
Published: August 2004

This article utilises data collected from a three-year ethnographic study of the Paulsgrove demonstrations against a local child sex offender and the local authorities, which took place in August 2000. It reassesses Silke's (2001) examination of the demonstrations, which suggested several ‘policing strategies' for dealing with vigilantism. In doing so we offer an alternative account of the demonstrations, outlining an 18-month aetiology which provides a wider understanding of the motivations of the protestors, as well as critically examining Silke's account of how the police deal with collective behaviour. We conclude that by examining the rationales for engaging in the protests one is able to gain a stronger understanding of the dynamics of crowd behaviour; which inevitably would be advantageous for future operational strategies for police officers charged with maintaining order on the streets.
Contactin Associates with Sodium Channel Nav1.3 in Native Tissues and Increases Channel Density at the Cell Surface
Authors: Shah Bhaval S. , Rush Anthony M. , Liu Shujun , Tyrrell Lynda , Black Joel A. , Dib-Hajj Sulayman D. , Waxman Stephen G.
Published: August 2004

The upregulation of voltage-gated sodium channel Nav1.3 has been linked to hyperexcitability of axotomized dorsal root ganglion (DRG) neurons, which underlies neuropathic pain. However, factors that regulate delivery of Nav1.3 to the cell surface are not known. Contactin/F3, a cell adhesion molecule, has been shown to interact with and enhance surface expression of sodium channels Nav1.2 and Nav1.9. In this study we show that contactin coimmunoprecipitates with Nav1.3 from postnatal day 0 rat brain where this channel is abundant, and from human embryonic kidney (HEK) 293 cells stably transfected with Nav1.3 (HEK-Nav1.3). Purified GST fusion proteins of the N and C termini of Nav1.3 pull down contactin from lysates of transfected HEK 293 cells. Transfection of HEK-Nav1.3 cells with contactin increases the amplitude of the current threefold without changing the biophysical properties of the channel. Enzymatic removal of contactin from the cell surface of cotransfected cells does not reduce the elevated levels of the Nav1.3 current. Finally, we show that, similar to Nav1.3, contactin is upregulated in axotomized DRG neurons and accumulates within the neuroma of transected sciatic nerve. We propose that the upregulation of contactin and its colocalization with Nav1.3 in axotomized DRG neurons may contribute to the hyper-excitablity of the injured neurons.
Synaptic Transformations Underlying Highly Selective Auditory Representations of Learned Birdsong
Authors: Coleman Melissa J. , Mooney R.
Published: August 2004

Stimulus-specific neuronal responses are a striking characteristic of several sensory systems, although the synaptic mechanisms underlying their generation are not well understood. The songbird nucleus HVC (used here as a proper name) contains projection neurons (PNs) that fire temporally sparse bursts of action potentials to playback of the bird's own song (BOS) but are essentially silent when presented with other acoustical stimuli. To understand how such remarkable stimulus specificity emerges, it is necessary to compare the auditory-evoked responsiveness of the afferents of HVC with synaptic responses in identified HVC neurons. We found that inactivating the interfacial nucleus of the nidopallium (NIf) could eliminate all auditory-evoked subthreshold activity in both HVC PN types, consistent with NIf serving as the major auditory afferent of HVC. Simultaneous multiunit extracellular recordings in NIf and intracellular recordings in HVC revealed that NIf population activity and HVC subthreshold responses were similar in their selectivity for BOS and that NIf spikes preceded depolarizations in all HVC cell types. These results indicate that information about the BOS as well as other auditory stimuli is transmitted synaptically from NIf to HVC. Unlike HVC PNs, however, HVC-projecting NIf neurons fire throughout playback of BOS as well as non-BOS stimuli. Therefore, temporally sparse BOS-evoked firing and enhanced BOS selectivity, manifested as an absence of suprathreshold responsiveness to non-BOS stimuli, emerge in HVC. The transformation to a sparse auditory representation parallels differences in NIf and HVC activity patterns seen during singing, which may point to a common mechanism for encoding sensory and motor representations of song.
The Role of Hippocampal Glutamate Receptor-A-Dependent Synaptic Plasticity in Conditional Learning: The Importance of Spatiotemporal Discontiguity
Authors: Schmitt Wolfram B. , Arianpour Roozbeh , Deacon Robert M. J. , Seeburg Peter H. , Sprengel Rolf , Rawlins J. Nicholas P. , Bannerman David M.
Published: August 2004

Gene-targeted mice lacking the AMPA receptor subunit glutamate receptor-A (GluR-A or GluR1) and mice with cytotoxic hippocampal lesions were compared with wild-type and sham-operated controls, respectively, on a conditional learning task using an elevated T-maze. Floor inserts (white perspex vs wire mesh) provided a conditional cue indicating in which goal arm a food reward was to be found. The relationship between the floor insert and the rewarded goal arm was constant throughout the experiment. Both lesioned and knock-out mice were able to acquire the task if the floor inserts extended throughout the entire maze, including the start arm and both goal arms. In contrast, both lesioned and knock-out mice were unable to acquire the task if the floor inserts were only present in the start arm of the maze. The absence of the conditional cue (the floor insert) at the time when the place-reward association was experienced thus critically determined whether or not the mice were impaired. We suggest that hippocampal GluR-A-dependent synaptic plasticity contributes to a memory system in rodents for encoding both the spatial and temporal contexts (the where and the when) associated with a particular event.
A Unique Role for Kv3 Voltage-Gated Potassium Channels in Starburst Amacrine Cell Signaling in Mouse Retina
Authors: Ozaita Ander , Petit-Jacques Jerome , Völgyi Béla , Ho Chi Shun , Joho Rolf H. , Bloomfield Stewart A. , Rudy Bernardo
Published: August 2004

Direction-selective retinal ganglion cells show an increased activity evoked by light stimuli moving in the preferred direction. This selectivity is governed by direction-selective inhibition from starburst amacrine cells occurring during stimulus movement in the opposite or null direction. To understand the intrinsic membrane properties of starburst cells responsible for direction-selective GABA release, we performed whole-cell recordings from starburst cells in mouse retina. Voltage-clamp recordings revealed prominent voltage-dependent K+currents. The currents were mostly blocked by 1 mmTEA, activated rapidly at voltages more positive than -20 mV, and deactivated quickly, properties reminiscent of the currents carried by the Kv3 subfamily of K+channels. Immunoblots confirmed the presence of Kv3.1 and Kv3.2 proteins in retina and immunohistochemistry revealed their expression in starburst cell somata and dendrites. The Kv3-like current in starburst cells was absent in Kv3.1-Kv3.2 knock-out mice. Current-clamp recordings showed that the fast activation of the Kv3 channels provides a voltage-dependent shunt that limits depolarization of the soma to potentials more positive than -20 mV. This provides a mechanism likely to contribute to the electrical isolation of individual starburst cell dendrites, a property thought essential for direction selectivity. This function of Kv3 channels differs from that in other neurons where they facilitate high-frequency repetitive firing. Moreover, we found a gradient in the intensity of Kv3.1b immunolabeling favoring proximal regions of starburst cells. We hypothesize that this Kv3 channel gradient contributes to the preference for centrifugal signal flow in dendrites underlying direction-selective GABA release from starburst amacrine cells
Stabilization of α-Synuclein Protein with Aging and Familial Parkinson's Disease-Linked A53T Mutation
Authors: Li Wenxue , Lesuisse Christian , Xu Yanqun , Troncoso Juan C. , Price Donald L. , Lee Michael K.
Published: August 2004

We examined the potential relationship between aging and α-synuclein (α-Syn) metabolism, both of which are implicated in the pathogenesis of Parkinson's disease (PD) and otherα-synucleinopathies. During aging,α-Syn and β-Syn mRNA expression in brain decreases, but the protein levels are maintained at high levels. Significantly, the α-Syn protein level increases with aging in human substantia nigra. Pulse-chase analyses of α-Syn half-lives in neurons and neuronal cell lines indicate that, in mature neurons, the expression of α-Syn is regulated by the post-translational stabilization of α-Syn protein. Moreover, A53T mutant human α-Syn exhibits increased stability in neuronal cell lines, leading to higher levels of the mutant protein in cells and transgenic mice. Inhibitor studies suggest that the proteasomal and lysosomal systems may not be responsible for the differential stabilization or metabolism of α-Syn protein in neuronal cells. Because increased stabilization of α-Syn protein is associated with increased protein levels and accumulation of pathogenic protein modifications, such as oxidative damage, the stabilization of α-Syn with aging may be a significant factor in the pathogenesis of α-synucleinopathies.
Gain and Loss of Channel Function by Alanine Substitutions in the Transmembrane Segments of the Rat ATP-Gated P2X2Receptor
Authors: Li Zhiyuan , Migita Keisuke , Samways Damien S. K. , Voigt Mark M. , Egan Terrance M.
Published: August 2004

ATP opens ionotropic P2X channels through a process that is poorly understood. We made an array of mutant rat P2X2channels containing unique alanine substitutions in the transmembrane segments with the goal of identifying possible secondary structure and mapping gating domains in the pore. Alteration of channel function was measured as a change in ATP potency, 2′-3′-O-(4-benzoylbenzoyl)ATP (BzATP) efficacy, and deactivation kinetics. Four mutants (V45A, Y47A, V51A, and D349A) failed to respond to ATP. Seven (H33A, Q37A, I40A, L41A, Y43A, F44A, and I50A) of 22 mutations in the first transmembrane segment (TM1) produced channels with altered potencies, and two mutants (Y43A and F44A) were active in the absence of agonist. The pattern of hits was consistent with a helical secondary structure. In contrast, nine (I328A, P329A, N333A, L338A, T339A, S340A, G342A, G344A, and S345A) of 24 mutations in the second transmembrane segment (TM2) resulted in a change in potency, but no regular pattern of impact was apparent. Many of the same mutations that altered ATP potency also changed the relative efficacy of the partial agonist BzATP. Together, these data suggest that both TM1 and TM2 participate in the conformational changes that occur during receptor activation and help to define domains involved in conformational switching within or near the pore.
Rapid Regulation of Pain by Estrogens Synthesized in Spinal Dorsal Horn Neurons
Authors: Evrard Henry C. , Balthazart Jacques
Published: August 2004

In addition to exerting genomic actions via nuclear receptors within hours to days, estrogens also regulate neuronal activity much faster (within seconds) by activating neuronal membrane receptors coupled to intracellular second-messenger pathways. To date, the origin of estrogens inducing rapid effects in the brain remains unclear, although it is often ascribed to the gonads. We report here that an acute blockade of the endogenous synthesis of estrogens in the quail spinal dorsal horn markedly reduced, within 1 min, the behavioral responsiveness to a thermal painful stimulus. Similar rapid effects in the opposite direction were induced by estradiol. This finding identifies a new paracrine and nongenomic mechanism for the regulation of pain by estrogens. Such regulation was assumed previously to result only from slow genomic actions of estrogens arising from the ovaries. Also, quite importantly, this finding suggests that the numerous rapid nongenomic effects of estrogens in the CNS could depend on their immediate local production by the enzyme aromatase, independently from the gonads.
μ-Opioid Receptor Trafficking on Inhibitory Synapses in the Rat Brainstem
Authors: Browning Kirsteen N. , Kalyuzhny Alexander E. , Travagli R. Alberto
Published: August 2004

Whole-cell recordings were made from identified gastric-projecting rat dorsal motor nucleus of the vagus (DMV) neurons. The amplitude of evoked IPSCs (eIPSCs) was unaffected by perfusion with met-enkephalin (ME) or by μ-, δ-, or κ-opioid receptor selective agonists, namelyd-Ala2-N-Me-Phe4-Glycol5-enkephalin (DAMGO), cyclic [d-Pen2-d-Pen5]-enkephalin, or trans-3,4-dichloro-N-methyl-N-[2-(1-pyrolytinil)-cyclohexyl]-benzeneacetamide methane sulfonate (U50,488), respectively. Brief incubation with the adenylate cyclase activator forskolin or the nonhydrolysable cAMP analog 8-bromo-cAMP, thyrotropin releasing hormone, or cholecystokinin revealed the ability of ME and DAMGO to inhibit IPSC amplitude; this inhibition was prevented by pretreatment with the μ-opioid receptor (MOR1) selective antagonistd-Phe-Cys-Tyr-d-Trp-Orn-Thr-Pen-Thr-NH2. Conversely, incubation with the adenylate cyclase inhibitor dideoxyadenosine, with the protein kinase A (PKA) inhibitorN-[2-(p-Bromocinnamyl-amino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H89), or with the Golgi-disturbing agent brefeldin A, blocked the ability of forskolin to facilitate the inhibitory actions of ME. Immunocytochemical experiments revealed that under control conditions, MOR1 immunoreactivity (MOR1-IR) was colocalized with glutamic acid decarboxylase (GAD)-IR in profiles apposing DMV neurons only after stimulation of the cAMP-PKA pathway. Pretreatment with H89 or brefeldin A or incubation at 4°C prevented the forskolin-mediated insertion of MOR1 on GAD-IR-positive profiles.

These results suggest that the cAMP-PKA pathway regulates trafficking of μ-opioid receptors into the cell surface of GABAergic nerve terminals. By consequence, the inhibitory actions of opioid peptides in the dorsal vagal complex may depend on the state of activation of brainstem vagal circuits.
Complex Locking Rather Than Complete Cessation of Neuronal Activity in the Globus Pallidus of a 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Treated Primate in Response to Pallidal Microstimulation
Authors: Bar-Gad Izhar , Elias Shlomo , Vaadia Eilon , Bergman Hagai
Published: August 2004

High-frequency stimulation of the globus pallidus (GP) has emerged as a successful tool for treating Parkinson's disease and other motor disorders. However, the mechanism governing its therapeutic effect is still under debate. To shed light on the basic mechanism of deep brain stimulation (DBS), we performed microstimulation in the GP of a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated monkey while recording with other microelectrodes in the same nucleus. We used robust methods to reduce the stimulus artifact, and 600-3000 repetitions of a single stimulus and of high-frequency short trains (10-40 stimuli), enabling high temporal resolution analysis of neural responses. Low-frequency stimulation yielded a typical three-stage response: short-term (2-3 msec duration) activity, followed by mid-term (15-25 msec) inhibition, and occasionally longer-term (30-40 msec) excitation. Trains of high-frequency stimuli elicited complex locking of the response to the stimuli in most neurons. The locking displayed a stereotypic temporal structure consisting of three short-duration (1-2 msec) phases: an initial (mean latency = 2.9 msec) excitation followed by an inhibition (4.6 msec) and a second excitation (6.3 msec). The change in the mean firing rate was mixed; the majority of the neurons displayed partial inhibition during the stimulus train. Slow inhibitory and excitatory multiphase changes in the firing rate were observed after the stimulus trains. The activity of neurons recorded simultaneously displayed rate correlations but no spike-to-spike correlations. Our results suggest that the effect of DBS on the GP is not complete inhibition but rather a complex reshaping of the temporal structure of the neuronal activity within that nucleus.
BDNF Regulates the Translation of a Select Group of mRNAs by a Mammalian Target of Rapamycin-Phosphatidylinositol 3-Kinase-Dependent Pathway during Neuronal Development
Authors: Schratt Gerhard M. , Nigh Elizabeth A. , Chen Wen G. , Hu Linda , Greenberg Michael E.
Published: August 2004

Local regulation of mRNA translation plays an important role in axon guidance, synaptic development, and neuronal plasticity. Little is known, however, regarding the mechanisms that control translation in neurons, and only a few mRNAs have been identified that are locally translated within axon and dendrites. Using Affymetrix gene arrays to identify mRNAs that are newly associated with polysomes after exposure to BDNF, we identified subsets of mRNAs for which translation is enhanced in neurons at different developmental stages. In mature neurons, many of these mRNAs encode proteins that are known to function at synapses, including CamKIIα, NMDA receptor subunits, and the postsynaptic density (PSD) scaffolding protein Homer2. BDNF regulates the translation of Homer2 locally in the synaptodendritic compartment by activating translational initiation via a mammalian target of rapamycin-phosphatidylinositol 3-kinase-dependent pathway. These findings suggest that BDNF likely regulates synaptic function by inducing the local synthesis of numerous synaptic proteins. The local translation of the cytoskeleton-associated protein Homer2 in particular might have important implications for growth cone dynamics and dendritic spine development.
A Role for Proinflammatory Cytokines and Fractalkine in Analgesia, Tolerance, and Subsequent Pain Facilitation Induced by Chronic Intrathecal Morphine
Authors: Johnston Ian N. , Milligan Erin D. , Wieseler-Frank Julie , Frank Matthew G. , Zapata Varlin , Campisi Jay , Langer Stephen , Martin David , Green Paula , Fleshner M. , Leinwand Leslie , Maier Steven F. , Watkins Linda R.
Published: August 2004

The present experiments examined the role of spinal proinflammatory cytokines [interleukin-1β (IL-1)] and chemokines (fractalkine) in acute analgesia and in the development of analgesic tolerance, thermal hyperalgesia, and tactile allodynia in response to chronic intrathecal morphine. Chronic (5 d), but not acute (1 d), intrathecal morphine was associated with a rapid increase in proinflammatory cytokine protein and/or mRNA in dorsal spinal cord and lumbosacral CSF. To determine whether IL-1 release modulates the effects of morphine, intrathecal morphine was coadministered with intrathecal IL-1 receptor antagonist (IL-1ra). This regimen potentiated acute morphine analgesia and inhibited the development of hyperalgesia, allodynia, and analgesic tolerance. Similarly, intrathecal IL-1ra administered after the establishment of morphine tolerance reversed hyperalgesia and prevented the additional development of tolerance and allodynia. Fractalkine also appears to modulate the effects of intrathecal morphine because coadministration of morphine with intrathecal neutralizing antibody against the fractalkine receptor (CX3CR1) potentiated acute morphine analgesia and attenuated the development of tolerance, hyperalgesia, and allodynia. Fractalkine may be exerting these effects via IL-1 because fractalkine (CX3CL1) induced the release of IL-1 from acutely isolated dorsal spinal cordin vitro. Finally, gene therapy with an adenoviral vector encoding for the release of the anti-inflammatory cytokine IL-10 also potentiated acute morphine analgesia and attenuated the development of tolerance, hyperalgesia, and allodynia. Taken together, these results suggest that IL-1 and fractalkine are endogenous regulators of morphine analgesia and are involved in the increases in pain sensitivity that occur after chronic opiates.
Evidence for Inhibition Mediated by Coassembly of GABAAand GABACReceptor Subunits in Native Central Neurons
Authors: Milligan Carol J. , Buckley Noel J. , Garret Maurice , Deuchars Jim , Deuchars Susan A.
Published: August 2004

Fast inhibition in the nervous system is commonly mediated by GABAAreceptors comprised of 2α/2β/1γ subunits. In contrast, GABACreceptors containing onlyρ subunits (ρ1-ρ3) have been predominantly detected in the retina. However, here using reverse transcription-PCR andin situhybridization we show that mRNA encoding the ρ1 subunit is highly expressed in brainstem neurons. Immunohistochemistry localized the ρ1 subunit to neurons at light and electron microscopic levels, where it was detected at synaptic junctions. Application of the GABACreceptor agonistcis-4-aminocrotonic acid (100-800 μM) requires the ρ1 subunit to elicit responses, which surprisingly are blocked independently by antagonists to GABAA(bicuculline, 10 μM) and GABAC[(1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid (TPMPA); 40-160 μM] receptors. Responses to GABACagonists were also enhanced by the GABAAreceptor modulator pentobarbitone (300 μM). Spontaneous and evoked IPSPs were reduced in amplitude but never abolished by TPMPA, but were completely blocked by bicuculline. We therefore tested the hypothesis that GABAAand GABACsubunits formed a heteromeric receptor. Immunohistochemistry indicated that ρ1 and α1 subunits were colocalized at light and electron microscopic levels. Electrophysiology revealed that responses to GABACreceptor agonists were enhanced by the GABAAreceptor modulator zolpidem (500 nm), which acts on the α1 subunit when the γ2 subunit is also present. Finally, coimmunoprecipitation indicated that the ρ1 subunit formed complexes that also containedα1 and γ2 subunits. Taken together these separate lines of evidence suggest that the effects of GABA in central neurons can be mediated by heteromeric complexes of GABAAand GABACreceptor subunits.
Brain-Derived Neurotrophic Factor Induces Hyperexcitable Reentrant Circuits in the Dentate Gyrus
Authors: Koyama Ryuta , Yamada Maki K. , Fujisawa Shigeyoshi , Katoh-Semba Ritsuko , Matsuki Norio , Ikegaya Yuji
Published: August 2004

Aberrant sprouting and synaptic reorganization of the mossy fiber (MF) axons are commonly found in the hippocampus of temporal lobe epilepsy patients and result in the formation of excitatory feedback loops in the dentate gyrus, a putative cellular basis for recurrent epileptic seizures. Usingex vivohippocampal cultures, we show that prolonged hyperactivity induces MF sprouting and the resultant network reorganizations and that brain-derived neurotrophic factor (BDNF) is necessary and sufficient to evoke these pathogenic plasticities. Hyperexcitation induced an upregulation of BDNF protein expression in the MF pathway, an effect mediated by L-type Ca2+channels. The neurotrophin receptor tyrosine kinase (Trk)B inhibitor K252a or function-blocking anti-BDNF antibody prevented hyperactivity-induced MF sprouting. Even under blockade of neural activity, local application of BDNF to the hilus, but not other subregions, was capable of initiating MF axonal remodeling, eventually leading to dentate hyperexcitability. Transfecting granule cells with dominant-negative TrkB prevented axonal branching. Thus, excessive activation of L-type Ca2+channels causes granule cells to express BDNF, and extracellularly released BDNF stimulates TrkB receptors present on the hilar segment of the MFs to induce axonal branching, which may establish hyperexcitable dentate circuits.
Fragile X Mental Retardation Protein Is Associated with Translating Polyribosomes in Neuronal Cells
Authors: Stefani Giovanni , Fraser Claire E. , Darnell Jennifer C. , Darnell Robert B.
Published: August 2004

Fragile X mental retardation protein (FMRP) is an RNA binding protein encoded by the geneFMR1, whose expression is impaired in patients with fragile X mental retardation. The association of FMRP with polyribosomes in non-neural cell lines has previously suggested that FMRP is involved in translational regulation. However, the relevance of these studies to neuronal function has been questioned by the finding that FMRP in brain is not associated with polyribosomes, but is part of small ribonucleo-protein complexes that do not appear to include ribosomes. Here we optimize methods to analyze brain polyribosomes, allowing us to definitively demonstrate that FMRP forms complexes with cortical brain polyribosomes. Moreover, we demonstrate in neuroblastoma cells that the FMRP-polyribosome complexes are sensitive to puromycin, a drug that targets actively translating ribosomes. These data indicate that FMRP associates with functional polyribosomes in neurons.
45,X/47,XXX/47,XX, del(Y)(p?)/46,XX mosaicism causing true hermaphroditism
Authors: Nieto Karem , Peña Rocío , Palma Icela , Dorantes Luis M. , Eraña Luis , Alvarez Rebeca , García‐Cavazos Ricardo , Kofman‐Alfaro Susana , Queipo Gloria
Published: August 2004

Sex differentiation in humans depends on the presence of the Y‐linked gene SRY, which is activated in the pre‐Sertoli cells of the developing gonadal primordium to trigger testicular differentiation. Occasionally testicular formation can take place in subjects lacking a Y chromosome resulting in a 46,XX sex reversal condition. True hermaphroditism (TH) is a rare form of intersexuality characterized by the presence of testicular and ovarian tissue in the same individual. Genetic heterogeneity has been proposed as a cause of dual gonadal development in some cases and recently, hidden mosaicism was reported to cause TH in some 46,XX SRY negative patients. Here we report a TH case in which hidden mosaicism for the Y and X chromosome was detected by PCR and FISH in peripheral blood and gonadal tissue, supporting the fact that mosaicism may cause TH and that molecular analysis of gonadal tissue should be performed in all 46,XX cases. © 2004 Wiley‐Liss, Inc.
Addition of a peptide fragment on an α‐helical depsipeptide induces α/310‐conjugated helix: Synthesis, crystal structure, and CD spectra of Boc–Leu–Leu–Ala–(Leu–Leu–Lac)3–Leu–Leu–OEt
Authors: Oku Hiroyuki , Ohyama Takafumi , Hiroki Akihiro , Yamada Keiichi , Fukuyama Keiichi , Kawaguchi Hiroyuki , Katakai Ryoichi
Published: August 2004

The depsipeptide Boc1–Leu2–Leu3–Ala4–Leu5–Leu6–Lac7–Leu8–Leu9–Lac10–Leu11–Leu12–Lac13–Leu14–Leu15–OEt16 (1) (Boc = tert‐butyloxycarbonyl, Lac = L‐lactic acid residue) has been synthesized from the peptide Boc–Leu–Leu–Ala–OEt (2) and a depsipeptide, Boc–(Leu–Leu–Lac)3–Leu–Leu–OEt (3). Single crystals of 1 were successfully obtained and the structure has been solved by direct methods (such as Sir2002 and Shake‐and‐Bake). Interestingly, 1 adopts an α/310‐conjugated helix containing a kink at the junction of peptide and depsipeptide segments, Leu3–Lac7. This is significantly different from the conformation of 3, which has a straight α‐helical structure with standard ϕ and ψ angles. Microcrystalline CD spectra were also studied to compare structural properties of 1 and 3. The differences between α/310‐ and α‐helices appear in these CD spectra. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
A critical and integrated view of the yeast interactome
Authors: Cornell Michael , Paton Norman W. , Oliver Stephen G.
Published: August 2004

Global studies of protein–protein interactions are crucial to both elucidating gene function and producing an integrated view of the workings of living cells. High‐throughput studies of the yeast interactome have been performed using both genetic and biochemical screens. Despite their size, the overlap between these experimental datasets is very limited. This could be due to each approach sampling only a small fraction of the total interactome. Alternatively, a large proportion of the data from these screens may represent false‐positive interactions. We have used the Genome Information Management System (GIMS) to integrate interactome datasets with transcriptome and protein annotation data and have found significant evidence that the proportion of false‐positive results is high. Not all high‐throughput datasets are similarly contaminated, and the tandem affinity purification (TAP) approach appears to yield a high proportion of reliable interactions for which corroborating evidence is available. From our integrative analyses, we have generated a set of verified interactome data for yeast. Copyright © 2004 John Wiley & Sons, Ltd.
Genome‐wide analysis of the effects of heat shock on a Saccharomyces cerevisiae mutant with a constitutively activated cAMP‐dependent pathway
Authors: Jones Dawn L. , Petty June , Hoyle David C. , Hayes Andrew , Oliver Stephen G. , Riba‐Garcia Isabel , Gaskell Simon J. , Stateva Lubomira
Published: August 2004

We have used DNA microarray technology and 2‐D gel electrophoresis combined with mass spectrometry to investigate the effects of a drastic heat shock from 30 °C to 50 °C on a genome‐wide scale. This experimental condition is used to differentiate between wild‐type cells and those with a constitutively active cAMP‐dependent pathway in Saccharomyces cerevisiae. Whilst more than 50% of the former survive this shock, almost all of the latter lose viability. We compared the transcriptomes of the wild‐type and a mutant strain deleted for the gene PDE2, encoding the high‐affinity cAMP phosphodiesterase before and after heat shock treatment. We also compared the two heat‐shocked samples with one another, allowing us to determine the changes that occur in the pde2Δ mutant which cause such a dramatic loss of viability after heat shock. Several genes involved in ergosterol biosynthesis and carbon source utilization had altered expression levels, suggesting that these processes might be potential factors in heat shock survival. These predictions and also the effect of the different phases of the cell cycle were confirmed by biochemical and phenotypic analyses. 146 genes of previously unknown function were identified amongst the genes with altered expression levels and deletion mutants in 13 of these genes were found to be highly sensitive to heat shock. Differences in response to heat shock were also observed at the level of the proteome, with a higher level of protein degradation in the mutant, as revealed by comparing 2‐D gels of wild‐type and mutant heat‐shocked samples and mass spectrometry analysis of the differentially produced proteins. Copyright © 2004 John Wiley & Sons, Ltd.
A case study on choosing normalization methods and test statistics for two‐channel microarray data
Authors: Xie Yang , Jeong Kyeong S. , Pan Wei , Khodursky Arkady , Carlin Bradley P.
Published: August 2004

DNA microarray analysis is a biological technology which permits the whole genome to be monitored simultaneously on a single slide. Microarray technology not only opens an exciting research area for biologists, but also provides significant new challenges to statisticians. Two very common questions in the analysis of microarray data are, first, should we normalize arrays to remove potential systematic biases, and if so, what normalization method should we use? Second, how should we then implement tests of statistical significance? Straightforward and uniform answers to these questions remain elusive. In this paper, we use a real data example to illustrate a practical approach to addressing these questions. Our data is taken from a DNA–protein binding microarray experiment aimed at furthering our understanding of transcription regulation mechanisms, one of the most important issues in biology. For the purpose of preprocessing data, we suggest looking at descriptive plots first to decide whether we need preliminary normalization and, if so, how this should be accomplished. For subsequent comparative inference, we recommend use of an empirical Bayes method (the B statistic), since it performs much better than traditional methods, such as the sample mean (M statistic) and Student's t statistic, and it is also relatively easy to compute and explain compared to the others. The false discovery rate (FDR) is used to evaluate the different methods, and our comparative results lend support to our above suggestions. Copyright © 2004 John Wiley & Sons, Ltd.
Comparative analysis of the testis and ovary transcriptomes in zebrafish by combining experimental and computational tools
Authors: Li Yang , Chia Jer Ming , Bartfai Richard , Christoffels Alan , Yue Gen Hua , Ding Ke , Ho Mei Yin , Hill James A. , Stupka Elia , Orban Laszlo
Published: August 2004

Studies on the zebrafish model have contributed to our understanding of several important developmental processes, especially those that can be easily studied in the embryo. However, our knowledge on late events such as gonad differentiation in the zebrafish is still limited. Here we provide an analysis on the gene sets expressed in the adult zebrafish testis and ovary in an attempt to identify genes with potential role in (zebra)fish gonad development and function. We produced 10 533 expressed sequence tags (ESTs) from zebrafish testis or ovary and downloaded an additional 23 642 gonad‐derived sequences from the zebrafish EST database. We clustered these sequences together with over 13 000 kidney‐derived zebrafish ESTs to study partial transcriptomes for these three organs. We searched for genes with gonad‐specific expression by screening macroarrays containing at least 2600 unique cDNA inserts with testis‐, ovary‐ and kidney‐derived cDNA probes. Clones hybridizing to only one of the two gonad probes were selected, and subsequently screened with computational tools to identify 72 genes with potentially testis‐specific and 97 genes with potentially ovary‐specific expression, respectively. PCR‐amplification confirmed gonad‐specificity for 21 of the 45 clones tested (all without known function). Our study, which involves over 47 000 EST sequences and specialized cDNA arrays, is the first analysis of adult organ transcriptomes of zebrafish at such a scale. The study of genes expressed in adult zebrafish testis and ovary will provide useful information on regulation of gene expression in teleost gonads and might also contribute to our understanding of the development and differentiation of reproductive organs in vertebrates. Copyright © 2004 John Wiley & Sons, Ltd.
A “Single‐Sample Concept” (SSC): A New Approach to the Combinatorial Chemistry of Inorganic Materials
Authors: Hulliger Jürg , Aslam Awan Muhammad
Published: August 2004

Combinatorial estimations show that, within an unreacted ceramic sample prepared by mixing N different starting materials MxOy with average particle size ∼1 μm, there are about 1012 grains per cubic centimeter, sufficient for local reactions to occur that may produce a larger number of product oxides than presently accessible by 2D plate techniques. The “single‐sample concept” (SSC) is proposed for performing property‐directed syntheses for the preparation of ferri‐/ferromagnetic or superconducting compounds. Because of the magnetic properties of the products, libraries of product grains can be sorted by means of magnetic separation techniques. For materials with a large magnetization, the separation efficiency is so high that traces of products can be isolated. The SSC concept was tested experimentally to prepare Fe‐based oxides (N=17, 24, 30). The large yields (<75 wt %, N=17) of product grains agree with the literature data, which indicate that 3d metal magnetic oxide phases (Tc>300 K) are most probably Fe oxides. In combination with magnetic separation techniques, SSC seems particularly adapted for exploring the solid‐state chemistry of metallic lead elements that form ferri‐/ferromagnetic or superconducting oxide phases difficult to detect systematically within the large phase space of theoretically existing compounds.
Cover Picture: A General and Versatile Approach to Thermally Generated N‐Heterocyclic Carbenes (Chem. Eur. J. 16/2004)
Authors: Nyce Gregory W. , Csihony Szilard , Waymouth Robert M. , Hedrick James L.
Published: August 2004

The cover picture shows the synthesis of pentafluorobenzene adducts of N‐heterocyclic carbenes (NHC), designed to undergo thermal deprotection to generate NHC. The utility of these adducts as organic catalyst precursors for living ring‐opening polymerization (ROP) of lactide, condensation polymerizations and transesterification reactions is described, as well as synthons for NHC bearing organometallic complexes by J. Hedrick et al. p. 4073 ff.
Conformational Analysis of Bis(L‐N,N‐dimethylvalinato)copper(II) and Bis(L‐N,N‐dimethylleucinato)copper(II) in Different Solvents by EPR Spectroscopy and a Molecular Mechanics Study
Authors: Mirosavljević Krunoslav , Sabolović Jasmina , Noethig‐Laslo Vesna
Published: August 2004

An EPR study on the Brownian motion of bis(L‐N,N‐dimethylvalinato)copper(II), Cu(L‐Me2Val)2 and bis(L‐N,N‐dimethylleucinato)copper(II), Cu(L‐Me2Leu)2, dissolved in different solvents (CD3OD, CH3CH2OH, CDCl3) as a function of temperature is presented. The theoretical fits of the EPR spectra revealed different EPR behaviour for the two copper(II) complexes in hydrogen bond making solvents. In order to examine whether the different behaviour could be explained on conformational (steric) grounds, a conformational analysis of the copper(II) complexes with L‐N,N‐dimethylated amino acids was performed with a molecular mechanics force field. The ability of the most stable conformations to bind a water molecule in the copper(II) first coordination sphere was also examined using the force field. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Structure Comparison of Early and Late Lanthanide(III) Homodinuclear Macrocyclic Complexes with the Polyamine Polycarboxylic Ligand H8OHEC
Authors: Böttger Ulrike A. , O’Sullivan Brendon , Ziemer Burkhard , Schumann Herbert , Mügge Clemens , Weißhoff Hardy
Published: August 2004

The solid‐state structures of two new homodinuclear chelate complexes with the late lanthanide(III) ions Yb and Lu, [Na2(Yb2OHEC)].14.5H2O (1), and [Na2(Lu2OHEC)].14.5H2O (2) (H8OHEC = 1,4,7,10,14,17,20,23‐octaazacyclohexacosane‐ 1,4,7,10,14,17,20,23‐octaacetic acid), have been determined by X‐ray crystal structure analysis. Each lanthanide(III) ion is coordinated by eight donor atoms of the ligand and the geometry of the coordination polyhedron approaches a bicapped trigonal prism. These structures are compared with those of the homodinuclear chelate complexes with the same ligand and the mid to early lanthanide(III) ions Gd, Eu, La and also Y. A distinctive structural change occurs across the lanthanide series. The centrosymmetric mid to early lanthanide(III) complexes are all ninefold‐coordinated in a capped square antiprismatic arrangement with a water molecule coordinated in a prismatic position. This structure is maintained in aqueous solution, together with an asymmetric minor isomer. The late lanthanide(III) OHEC complexes not only lack the inner‐sphere water, but the change of coordination sphere also results in a loss of symmetry of the whole complex molecule. The observed change of coordination mode and number of the lanthanide ion may offer a geometric model for the isomerization process in eight‐ and ninefold‐coordinated complex species that are isomers in a possible coordination equilibrium observed by NMR in aqueous solution. This model may also explain the intramolecular rearrangements necessary during water exchange in the inner coordination sphere of the complex [(Gd2OHEC)(H2O)2]2− through a slow dissociative mechanism. Protonation constants of the H8OHEC ligand and complex formation constants of this ligand with GdIII, CaII, CuII and ZnII have been determined by solution thermodynamic studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Boranophosphate Salts as an Excellent Mimic of Phosphate Salts: Preparation, Characterization, and Properties
Authors: Nahum Victoria , Fischer Bilha
Published: August 2004

We report on the preparation of boranophosphate salts, BPi (2), and the exploration of their properties with a view to developing a new mimic of the parent phosphate. BPi salts were easily prepared in excellent yield in a one‐pot two‐step reaction from tris(trimethylsilyl) phosphite, and were characterized by X‐ray crystallography and IR, 1H and 31P NMR spectroscopy. We evaluated the acid/base character of BPi by determining its acidity constants. Likewise, we evaluated the stability of BPi at various pH values, and calculated the decomposition‐rate constants at highly acidic pH. We also monitored the H‐bonded clustering of BPi in organic solvents, including MeOH. Finally, we explored the chemical behavior of BPi with respect to various organic and inorganic reagents. BPi is stable under the following conditions: both basic and acidic pH (pH > 2), in the presence of amines, and in the presence of Mg2+ ions. However, a P−B bond cleavage is observed upon the reaction of BPi with carbodiimides or upon catalytic hydrogenation. The reducing nature of the BH3 moiety is drastically decreased in BPi. Likewise, the nucleophilicity of BPi’s oxygen atom is lower than in phosphate, Pi, salts. Based on its water solubility, acid‐base character, and H‐bonding properties, BPi appears as a perfect mimic of Pi and is an attractive alternative to the known phosphate isosters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Dinuclear ZnII Complexes of Polydentate Polyamines as Minimalist Models of Hydrolytic Reactions
Authors: Aguilar Juan , Bencini Andrea , Berni Emanuela , Bianchi Antonio , García‐España Enrique , Gil Laura , Mendoza Angel , Ruiz‐Ramírez Lena , Soriano Conxa
Published: August 2004

The synthesis of the novel macrocycle 2,6,9,12,16‐pentaaza[17](2,9)(1,10)phenanthrolinophane (L3) is reported. Speciation studies on the systems ZnII−L3 and ZnII−L2 (L2 =2,6,10,13,17,21‐hexaaza[22]metacyclophane) performed in aqueous solution show the formation of mono‐ and dinuclear ZnII complexes. In the two systems, the dinuclear complexes readily hydroxylate, with the hydroxo species being the main ones in solution at relatively low pH values. This feature makes these complexes promising hydrolytic agents for carboxy and phosphate esters. The hydrolytic ability of the L1−L3 dinuclear complexes toward the carboxy and phosphate ester bond was tested by addition of p‐nitrophenyl acetate (NA) and bis(p‐nitrophenyl)phosphate (BNP). While in the case of NA the cleavage takes place through a simple bimolecular mechanism and the hydrolysis rate depends on the nucleophilicity of the ZnII−OH functions, in the case of BNP the hydrolytic mechanism involves substrate interaction with the metal ions and nucleophilic attack of a ZnII‐bound hydroxide ion at the phosphorus atom. The L3 complex gives rise to the highest hydrolysis rate constant {k = 62 × 10−5 M−1·s−1 vs. k = 8 × 10−5 and 4 × 10−5 M−1·s−1 for [Zn2L2(OH)2]2+ and [Zn2L1(OH)2]2+, respectively}. This may be related to a stronger interaction with the substrate due to the synergetic role in BNP binding played by the phenanthroline unit, which can give π‐stacking and hydrophobic interactions with the aromatic units of the substrate, and by the two ZnII ions, which can act cooperatively in BNP coordination. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Formation of Thermotropic and Lyotropic Liquid Crystals of Bis(N‐alkylethylenediamine)silver(I) Nitrate
Authors: Iida Masayasu , Inoue Michiko , Tanase Tomoaki , Takeuchi Takae , Sugibayashi Makiko , Ohta Kazuchika
Published: August 2004

We have synthesized bis(N‐hexylethylenediamine)silver(I) nitrate ([Ag(hex‐en)2]NO3), bis(N‐octylethylenediamine)silver(I) nitrate ([Ag(oct‐en)2]NO3), and bis(N‐dodecylethylenediamine)silver(I) nitrate ([Ag(dod‐en)2]NO3) and investigated the aggregation behavior of [Ag(dod‐en)2]NO3 and [Ag(oct‐en)2]NO3 in the liquid state. An X‐ray crystallographic analysis revealed that [Ag(dod‐en)2]NO3 has a dinuclear structure in the crystalline state — the molecular composition unit is [Ag2(dod‐en)4](NO3)2, where the two dod‐en ligands bridge two silver ions that are coordinated by four nitrogen atoms. The dinuclear complex is appreciably dissociated into a mononuclear complex in solution. It was found that [Ag(oct‐en)2]NO3 and [Ag(dod‐en)2]NO3 form thermotropic liquid crystals in the temperature ranges 48−67 °C and 59−96 °C, respectively, and a lyotropic liquid crystal was also observed for [Ag(dod‐en)2]NO3 in n‐heptane at around room temperature in the presence of a small amount of water. The structures of the thermotropic and lyotropic liquid crystals of [Ag(dod‐en)2]NO3 were identified as a typical smectic A (SA) type and a nematic one, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Cationic Tetranuclear [NiII4(MeOH)2(pko)6]2+ Cluster Showing Antiferro‐ and Ferromagnetic Features
Authors: Alexiou Maria , Dendrinou‐Samara Catherine , Raptopoulou Catherine P. , Terzis Aris , Tangoulis Vassilis , Kessissoglou Dimitris P.
Published: August 2004

The majority of reported nickel tetranuclear clusters have a dicubane‐like structural core. The compound presented here is the second example possessing an Ni4O2 core based on a chair or butterfly “out‐of‐face” topology. This compound also belongs to the family of compounds characterized as metallacrowns with an [Ni−N−O−]n linkage and is the only example with three Ni−O−N−Ni strands bridging the nickel atoms. The values obtained from the fitting procedure are J1 = 55.8 cm−1, J2 = −67.2 cm−1, g = 2.2, ρ = 1.1%. These values suggest the presence of both ferromagnetic and antiferromagnetic interactions, while a small paramagnetic impurity is also present. This magnetic behaviour with antiferromagnetic internal coupling and ferromagnetic spin‐alignment is the second example in the literature and the first in the metallacrown family. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)