bluuebunny/crossref_metadata_2025 huggingface dataset:
DFsn collaborates with Highwire to down-regulate the Wallenda/DLK kinase and restrain synaptic terminal growth
Authors: Wu Chunlai , Daniels Richard W , DiAntonio Aaron
Published: August 2007

Background

The growth of new synapses shapes the initial formation and subsequent rearrangement of neural circuitry. Genetic studies have demonstrated that the ubiquitin ligase Highwire restrains synaptic terminal growth by down-regulating the MAP kinase kinase kinase Wallenda/dual leucine zipper kinase (DLK). To investigate the mechanism of Highwire action, we have identified DFsn as a binding partner of Highwire and characterized the roles of DFsn in synapse development, synaptic transmission, and the regulation of Wallenda/DLK kinase abundance.

Results

We identified DFsn as an F-box protein that binds to the RING-domain ubiquitin ligase Highwire and that can localize to the Drosophila neuromuscular junction. Loss-of-function mutants for DFsn have a phenotype that is very similar to highwire mutants – there is a dramatic overgrowth of synaptic termini, with a large increase in the number of synaptic boutons and branches. In addition, synaptic transmission is impaired in DFsn mutants. Genetic interactions between DFsn and highwire mutants indicate that DFsn and Highwire collaborate to restrain synaptic terminal growth. Finally, DFsn regulates the levels of the Wallenda/DLK kinase, and wallenda is necessary for DFsn-dependent synaptic terminal overgrowth.

Conclusion

The F-box protein DFsn binds the ubiquitin ligase Highwire and is required to down-regulate the levels of the Wallenda/DLK kinase and restrain synaptic terminal growth. We propose that DFsn and Highwire participate in an evolutionarily conserved ubiquitin ligase complex whose substrates regulate the structure and function of synapses.
Securinine, a GABAA receptor antagonist, enhances macrophage clearance of phase IIC. burnetii: comparison with TLR agonists
Authors: Lubick Kirk , Radke Miranda , Jutila Mark
Published: August 2007

Innate immune cell stimulation represents a complementary approach to vaccines and antimicrobial drugs to counter infectious disease. We have used assays of macrophage activation and in vitro and in vivo phase II Coxiella burnetii infection models to compare and contrast the activity of a novel innate immune cell agonist, securinine, with known TLR agonists. As expected, TLR agonists, such as LPS (TLR4) and fibroblast-stimulating lipopeptide-1 (FSL-1; TLR2), induced macrophage activation and increased macrophage killing of phase II C. burnetii in vitro. FSL-1 also induced accelerated killing of C. burnetii in vivo. Securinine, a γ-aminobutyric acid type A receptor antagonist, was found to induce TLR-independent macrophage activation in vitro, leading to IL-8 secretion, L-selectin down-regulation, and CD11b and MHC Class II antigen up-regulation. As seen with the TLR agonists, securinine also induced accelerated macrophage killing of C. burnetii in vitro and in vivo. In summary, as predicted by the literature, TLR agonists enhance macrophage killing of phase II C. burnetii in vitro, and at least for TLR2 agonists, this activity occurs in vivo as well. Securinine represents a novel macrophage agonist, which has similar effects as TLR agonists in this model yet apparently, does not act through known TLRs. Securinine has minimal toxicity in vivo, suggesting it or structurally similar compounds may represent novel, therapeutic adjuvants, which increase resistance to intracellular pathogens.
Mycoplasmacontaminants present in exosome preparations induce polyclonal B cell responses
Authors: Quah Ben J C , O’Neill Helen C
Published: August 2007

Exosome fractions of dendritic cells (DC) produced in long-term cultures (LTC) were found to contain Mycoplasma contaminants. In this study, Mycoplasma-infected, -uninfected, and -reinfected cultures of DC and control cell lines have been compared for their capacity to activate lymphocytes. Using differential centrifugation, size fractionation, and inhibition assays, it has been possible to map Mycoplasma to the exosome or vesicle fraction purified from culture supernatant (CSN). Mycoplasma fractions were shown to induce proliferation of B and not T cells. The B cell response was sensitive to mitomycin C and primaquine, both known antibiotics, but resistant to protease and DNase, suggesting a role for lipoproteins. Mycoplasma-contaminated exosome fractions of LTC-DC were potent mitogens for naive B cells and promoted Ig secretion. In contrast to the polyclonal B cell mitogen LPS, they were unable to promote Ig isotype switching. They induced polyclonal activation of all B cell subsets, including naive B cells, the T1 and T2 subsets of transitional B cells, marginal zone (MZ), and follicular (FO) B cells. The B cell proliferative response was not antigen-specific and occurred independently of T cell help. Implications for autoimmune sequelae associated with Mycoplasma infection are discussed along with the possibility that primaquine could be an effective treatment for Mycoplasma infection in humans. This study highlights the close association between exosomes and infectious agents like Mycoplasma and cautions about purification procedures for preparation of exosomes for studies on immunity.
CCR7 mediates the migration of Foxp3+ regulatory T cells to the paracortical areas of peripheral lymph nodes through high endothelial venules
Authors: Ueha Satoshi , Yoneyama Hiroyuki , Hontsu Shigeto , Kurachi Makoto , Kitabatake Masahiro , Abe Jun , Yoshie Osamu , Shibayama Shiro , Sugiyama Tetsuya , Matsushima Kouji
Published: August 2007

Thymus-derived forkhead box p3+ naturally occurring regulatory T cells (nTreg) are thought to circulate throughout the body to maintain peripheral immunological self-tolerance through interactions with dendritic cells (DCs), resulting in regulation of conventional T cells. However, the chemokine receptors, which are putatively involved in the in vivo migration of nTreg, have not been fully established. Here, we demonstrated that lymph node nTreg preferentially migrated to the paracortical area of lymph nodes after adoptive transfer, where they were observed to make contact frequently with CD8α+ DCs and CD8α− CD11b− DCs. This migration of nTreg to the paracortical areas was impaired severely when cells were prepared from CCR7-deficient mice. However, to some extent, CCR7-independent migration of nTreg in such CCR7-deficient mice was also observed, but this occurred mainly in the medullary high endothelial venules. Taken together, these data provide the evidence that CCR7 mediates nTreg migration to the paracortical areas of lymph nodes under steady-state conditions; however, CCR7-independent migration also takes place in the medulla.
Childhood Metabolic Syndrome and Its Components in Premature Adrenarche
Authors: Utriainen Pauliina , Jääskeläinen Jarmo , Romppanen Jarkko , Voutilainen Raimo
Published: August 2007

Context: Premature pubarche (PP), the main clinical manifestation of premature adrenarche (PA), has been associated with insulin resistance and dyslipidemia in selected populations.

Objectives: Our aim was to determine the prevalence of childhood metabolic syndrome (cMBS) and to study its components in prepubertal Northern European girls with PA.

Design and Patients: We conducted a cross-sectional study on 63 prepubertal girls with PA (32 with PP = PP-PA, 31 without PP = nonPP-PA) and 80 healthy age-matched control girls. A standard 2-h oral glucose tolerance test with insulin sampling was performed. Plasma lipids and serum SHBG were analyzed, and blood pressure and weight-for-height were recorded. cMBS was defined by modified criteria of the U.S. National Cholesterol Education Project Adult Treatment Panel III and the World Health Organization.

Setting: The study was performed at University Hospital.

Results: The mean weight-for-height (P = 0.002) and the prevalence of cMBS by the modified Adult Treatment Panel III (24 vs. 10%) and World Health Organization definitions (16 vs. 5%) (P < 0.05 for both) were higher in the PA than control girls. The weight-for-height adjusted serum insulin concentrations during the oral glucose tolerance test were elevated in the whole PA group, whereas the fasting insulin concentrations were increased and SHBG was decreased only in the PP-PA subgroup. The weight-for-height adjusted blood pressure, lipid, or glucose levels did not differ between the study groups.

Conclusions: Prepubertal Northern European PA girls have increased prevalence of cMBS mainly due to being overweight and their hyperinsulinism. Among the PA children, the nonPP-PA girls have milder metabolic changes than the PP-PA girls.
Differential targeting of secretory lysosomes and recycling endosomes in mast cells revealed by patterned antigen arrays
Authors: Wu Min , Baumgart Tobias , Hammond Stephanie , Holowka David , Baird Barbara
Published: August 2007

Polarized response towards a contact interface is a common theme in intercellular signaling. To visualize spatial regulation of stimulated secretion within a contact region, we exposed IgE-sensitized rat basophilic leukemia (RBL) mast cells to a surface that was patterned on the μm scale with hapten-containing lipid bilayers to activate cell surface IgE-receptor complexes. We find that, within 10 minutes of stimulation, fusion of individual secretory lysosomes is targeted towards the cell-substrate interface, but is spatially segregated from the patterned bilayers and receptor signaling complexes. By contrast, stimulated outward trafficking of recycling endosomes is preferentially targeted towards the patterned bilayers. High spatial resolution of both antigen presentation in these arrays and detection of exocytotic events provides direct evidence for the heterogeneity of polarized responses.
Regulation of meiotic cohesion and chromosome core morphogenesis during pachytene inDrosophilaoocytes
Authors: Khetani Radhika S. , Bickel Sharon E.
Published: August 2007

During meiosis, cohesion between sister chromatids is required for normal levels of homologous recombination, maintenance of chiasmata and accurate chromosome segregation during both divisions. In Drosophila, null mutations in the ord gene abolish meiotic cohesion, although how ORD protein promotes cohesion has remained elusive. We show that SMC subunits of the cohesin complex colocalize with ORD at centromeres of ovarian germ-line cells. In addition, cohesin SMCs and ORD are visible along the length of meiotic chromosomes during pachytene and remain associated with chromosome cores following DNase I digestion. In flies lacking ORD activity, cohesin SMCs fail to accumulate at oocyte centromeres. Although SMC1 and SMC3 localization along chromosome cores appears normal during early pachytene in ord mutant oocytes, the cores disassemble as meiosis progresses. These data suggest that cohesin loading and/or accumulation at centromeres versus arms is under differential control during Drosophila meiosis. Our experiments also reveal that the α-kleisin C(2)M is required for the assembly of chromosome cores during pachytene but is not involved in recruitment of cohesin SMCs to the centromeres. We present a model for how chromosome cores are assembled during Drosophila meiosis and the role of ORD in meiotic cohesion, chromosome core maintenance and homologous recombination.
Update on the Pharmacotherapy of Obesity
Authors: Cerulli Jennifer , Lomaestro Ben M , Malone Margaret
Published: August 2007

Objective:

To review recent developments in the pharmacotherapy of obesity, including the agents currently approved for use in the management of obesity and those under development.

Data Sources:

A MEDLINE search from January 1990 to July 1997 was conducted to identify English literature available on the pharmacotherapy of obesity. The search was supplemented by a review of the bibliographies of identified literature.

Study Selection:

All controlled and uncontrolled trials were reviewed. When available, double-blind, placebo-controlled trials were used preferentially.

Data Extraction:

Agents were reviewed with regard to mechanism of action, clinical trial data regarding efficacy, adverse effects, pharmacokinetics, drug interactions, and contraindications where information was available. Study design, selected population, results, and adverse effect information were included.

Data Synthesis:

The anorexiants currently available or under development for the management of obesity regulate food intake and satiety via the adrenergic and/or serotonergic pathways. Clinical trials have shown a 10–15% weight loss can typically be anticipated; however, little long-term safety and efficacy data are available. Adverse events tend to be mild and self-limiting, but serious adverse events can occur. Treatment options under development include thermogenic agents, digestive inhibitors, and analogs and antagonists of hormones that regulate food intake and satiety.

Conclusions:

Several mechanisms to control weight are currently under investigation for the management of obesity. Since obesity is a chronic condition, further studies should be conducted to evaluate the long-term safety and efficacy of these agents and the role of combination therapy using different modalities.
Analysis of Flavonoid Phytoestrogens in Botanical and Ephedra-Containing Dietary Supplements
Authors: Grippo Anne A , Capps Kayla , Rougeau Ben , Gurley Bill J
Published: August 2007

Background:

Plant-derived botanical and dietary supplements are widely self-prescribed in the US and considered natural, safe, and beneficial. However, because they are not strictly regulated by the Food and Drug Administration (FDA), their ingredients are not always known and they may contain unexpected agents. Among the myriad plant-produced molecules are flavonoids, which reportedly have various human health effects, including anticancer, antioxidant, and estrogenic properties. Several flavonoids (eg, isoflavones) are known as phytoestrogens, based on their ability to mimic estrogen in mammals. Because botanical and dietary supplements are plant products and need not be processed or purified due to their FDA classification as foods, they may contain unexpected phytoestrogens, such as flavonoids.

Objective:

To analyze 8 botanical and 11 ephedra-containing dietary supplements for the presence and concentration of 5 flavonoids (biochanin A, daidzein, formononetin, genistein, quercetin), which may deliver unexpected estrogenic activity.

Method:

Randomly selected tablets from single bottles of 19 botanical and dietary supplements purchased locally were pooled. Flavonoids were extracted into ethanolic solution and analyzed by high-performance liquid chromatography.

Results:

Flavonoids were detected in all supplements tested, with the largest number (4) found in Kava Kava. Almost all supplements contained measurable amounts of genistein and/or daidzein, known estrogenic agents, at up to 22 mg/day of isoflavone, per recommended daily dosage of supplement.

Conclusions:

These results suggest that single-component botanical and multi-ingredient dietary supplements could contain unexpected estrogenic agents, which may impact the health of consumers.
Impact of a Protocol for Prevention of Ventilator-Associated Pneumonia
Authors: Omrane Rajae , Eid Jihane , Perreault Marc M , Yazbeck Hala , Berbiche Djamal , Gursahaney Ashvini , Moride Yola
Published: August 2007

Background:

Several interventions have been shown to be effective in reducing the incidence of ventilator-associated pneumonia (VAP), but their implementation in clinical practice has not gained widespread acceptance.

Objective:

To determine the impact of a protocol that incorporates evidence-based interventions shown to reduce the frequency of VAP on the overall rate of VAP, early-onset VAP, and late-onset VAP in the intensive care unit (ICU) of a tertiary care adult teaching hospital.

Methods:

This pre- and postintervention observational study included mechanically ventilated patients admitted to the Montreal General Hospital ICU between November 2003 and May 2004 (preintervention) and between November 2004 and May 2005 (postintervention). A multidisciplinary prevention protocol was developed, implemented, and reinforced. Rates of VAP per 1000 ventilator-days were calculated pre- and postprotocol implementation for all patients, for patients with early-onset VAP, and for those with late-onset VAP.

Results:

In the pre- and postintervention groups, 349 and 360 patients, respectively, were mechanically ventilated. Twenty-three VAP episodes occurred in 925 ventilator-days (crude incidence rate 25 per 1000) in the preintervention period. Following implementation, the VAP rate decreased to 22 episodes in 988 ventilatordays (crude incidence rate 22.3 per 1000), corresponding to a relative reduction in rate of 10.8% (p < 0.001). The incidence of early-onset VAP decreased from 31.0 to 18.5 VAP per 1000 ventilator-days (p < 0.001), while the incidence of late-onset VAP increased from 21.9 to 24.1 VAP per 1000 ventilator-days (p < 0.001). However, when all covariates were adjusted, the impact of the prevention protocol was not statistically significant.

Conclusions:

Implementation of a VAP prevention protocol incorporating evidence-based interventions reduced the crude incidence of VAP, early-onset VAP, and late-onset VAP. However, when covariates were adjusted, the beneficial effect was no longer observed. Further research is needed to assess the impact of such measures on VAP, early-onset VAP, and late-onset VAP.
Successful Treatment of Previously Uncontrolled Adult Asthma with Budesonide Inhalation Suspension: Five-Year Case Histories
Authors: Gawchik Sandra M
Published: August 2007

Objective:

To determine whether nebulized budesonide inhalation suspension (BIS) is effective in treating adults with asthma that has been uncontrolled by inhaled therapies.

Case Summaries:

Three adults with severe persistent asthma were switched to BIS after poor outcomes with other controller medications, including inhaled corticosteroids (ICSs). BIS dosages were initiated with 1 mg twice daily. Based on physician discretion as symptoms improved, dosages were decreased to 0.5 mg twice daily (2 pts.) or once daily (1 pt.). Patients were instructed to self-manage their asthma, increasing their dosages during periods of asthma worsening. Peak expiratory flow (PEF) was assessed before and after the initiation of BIS. The number of healthcare visits and oral corticosteroid courses recorded in patient medical records during the 3 years before and 5 years after initiation of BIS therapy were compared. In all 3 cases, BIS improved asthma control. BIS consistently increased PEF and reduced the number of urgent care visits and oral corticosteroid courses. All patients reported satisfaction with BIS therapy.

Discussion:

Despite proven effectiveness of ICSs for persistent asthma, some patients fail to respond optimally to treatment administered via an inhaler. These 3 case reports suggest that BIS is effective in treating adults with severe persistent asthma who fail to respond optimally to treatment with other ICS preparations. Failure to use inhalers properly, previous poor adherence in 1 case, or patient preference for the nebulizer might explain why nebulized BIS was more effective than other inhaler therapies.

Conclusions:

Switching adults with uncontrolled asthma to BIS therapy may be a valuable treatment option for those who are unable to achieve optimal asthma control, despite asthma education and training on inhaler technique.
Comprehension of pretence in children with autism
Authors: Bigham Sally
Published: August 2007

Impairments of pretend play are a diagnostic characteristic of autism. This has been interpreted in terms of a generative impairment. Specifically, children with autism are unable to generate the ideas for pretend play despite an intact underlying ability to understand pretence. The notion of a performance deficit affecting production only has, in part, been based upon observations that children with autism appear to have no difficulty understanding pretence. However, research investigating comprehension is somewhat limited and has only investigated a specific type of pretend play, namely pretend properties. The research reported here investigated the ability of children with autism to understand object substitution pretence and pretend gestures (i.e. using no substitutes). Children with autism (N = 36) matched for verbal ability (between 3 and 6 years) with typically developing children (N = 55) and children with moderate learning difficulties (N = 37) were questioned about a series of pretend actions, such as writing. The results revealed three main findings. First, children with autism appear to experience no notable difficulties comprehending functional play. Second, children with autism do encounter difficulties comprehending pretend play. A performance deficit is unable to explain these findings and it is suggested that there may be a more critical impairment in understanding how absent objects are represented. Finally, there was a trend for some kinds of object substitutions and gestures to be more impaired than others. One tentative interpretation is that as the degree of similarity between the referent and the substitute diminishes the representational connection becomes more difficult to understand, particularly when there is a need to inhibit salient but irrelevant cues.
Case History of the Use of Electronic Survey Techniques to Assess Planar Distortions in Building Facades
Authors: Coll Kevin S. , VanOcker David A.
Published: August 2007

The occurrence of distortions within facade elements in the form of leaning, bowed and vertically displaced wall construction is common in older structures. Quite often these conditions are identified by building owners and serve as the primary focus of investigations to assess their significance. Quantifying the severity and extent of these displacements is integral to these evaluations. Various surveying methods are available to assist the investigator in determining planar distortions, ranging from simple plumb bob and level surveys to digital electronic surveying techniques. This paper focuses on the use of electronic surveying techniques as a diagnostic tool in assessing planar distortions and displacement in three dimensions on building facades. A case study is presented as a typical application where planar displacements within a building facade needed to be assessed. To provide context for selection, use, and interpretation of various survey techniques, a project is reviewed in detail from initial identification of displacements, review/selection of an appropriate survey technique, manipulation, and interpretation of survey data, assessing the significance of the data relative to the case study building, and review of repair program parameters.
TrpC3/C7 and Slo2.1 Are Molecular Targets for Metabotropic Glutamate Receptor Signaling in Rat Striatal Cholinergic Interneurons
Authors: Berg Allison P. , Sen Neil , Bayliss Douglas A.
Published: August 2007

Large aspiny cholinergic interneurons provide the sole source of striatal acetylcholine, a neurotransmitter critical for basal ganglia function; these tonically active interneurons receive excitatory inputs from corticostriatal glutamatergic afferents that act, in part, via metabotropic glutamate receptors (mGluRs). We combined electrophysiological recordings in brain slices with molecular neuroanatomy to identify distinct ion channel targets for mGluR1/5 receptors in striatal cholinergic interneurons: transient receptor potential channel 3/7 (TrpC3/C7) and Slo2.1. In recordings obtained with methanesulfonate-based internal solutions, we found an mGluR-activated current with voltage-dependent and pharmacological properties reminiscent of TrpC3 and TrpC7; expression of these TrpC subunits in cholinergic interneurons was verified by combined immunohistochemistry andin situhybridization, and modulation of both TrpC channels was reconstituted in HEK293 (human embryonic kidney 293) cells cotransfected with mGluR1 or mGluR5. With a chloride-based internal solution, mGluR agonists did not activate interneuron TrpC-like currents. Instead, a time-dependent, outwardly rectifying K+current developed after whole-cell access, and this Cl−-activated K+current was strongly inhibited by volatile anesthetics and mGluR activation. This modulation was recapitulated in cells transfected with Slo2.1, a Na+- and Cl−-activated K+channel, and Slo2.1 expression was confirmed histochemically in striatal cholinergic interneurons. By using gramicidin perforated-patch recordings, we established that the predominant agonist-activated current was TrpC-like when ambient intracellular chloride was preserved, although a small K+current contribution was observed in some cells. Together, our data indicate that mGluR1/5-mediated glutamatergic excitation of cholinergic interneurons is primarily a result of activation of TrpC3/TrpC7-like cationic channels; under conditions when intracellular NaCl is elevated, a Slo2.1 background K+channel may also contribute.
Calcineurin in Reactive Astrocytes Plays a Key Role in the Interplay between Proinflammatory and Anti-Inflammatory Signals
Authors: Fernandez Ana M. , Fernandez Silvia , Carrero Paloma , Garcia-Garcia Miguel , Torres-Aleman Ignacio
Published: August 2007

Maladaptive inflammation is a major suspect in progressive neurodegeneration, but the underlying mechanisms are difficult to envisage in part because reactive glial cells at lesion sites secrete both proinflammatory and anti-inflammatory mediators. We now report that astrocytes modulate neuronal resilience to inflammatory insults through the phosphatase calcineurin. In quiescent astrocytes, inflammatory mediators such as tumor necrosis factor-α (TNF-α) recruits calcineurin to stimulate a canonical inflammatory pathway involving the transcription factors nuclear factor κB (NFκB) and nuclear factor of activated T-cells (NFAT). However, in reactive astrocytes, local anti-inflammatory mediators such as insulin-like growth factor I also recruit calcineurin but, in this case, to inhibit NFκB/NFAT. Proof of concept experimentsin vitroshowed that expression of constitutively active calcineurin in astrocytes abrogated the inflammatory response after TNF-α or endotoxins and markedly enhanced neuronal survival. Furthermore, regulated expression of constitutively active calcineurin in astrocytes markedly reduced inflammatory injury in transgenic mice, in a calcineurin-dependent manner. These results suggest that calcineurin forms part of a molecular pathway whereby reactive astrocytes determine the outcome of the neuroinflammatory process by directing it toward either its resolution or its progression.
Long-Term Consequences of Methamphetamine Exposure in Young Adults Are Exacerbated in Glial Cell Line-Derived Neurotrophic Factor Heterozygous Mice
Authors: Boger Heather A. , Middaugh Lawrence D. , Patrick Kennerly S. , Ramamoorthy Sammanda , Denehy Emily D. , Zhu Haojie , Pacchioni Alejandra M. , Granholm Ann-Charlotte , McGinty Jacqueline F.
Published: August 2007

Methamphetamine abuse in young adults has long-term deleterious effects on brain function that are associated with damage to monoaminergic neurons. Administration of glial cell line-derived neurotrophic factor (GDNF) protects dopamine neurons from the toxic effects of methamphetamine in animal models. Therefore, we hypothesized that a partialGDNFgene deletion would increase the susceptibility of mice to methamphetamine neurotoxicity during young adulthood and possibly increase age-related deterioration of behavior and dopamine function. Two weeks after a methamphetamine binge (4 × 10 mg/kg, i.p., at 2 h intervals),GDNF+/−mice had a significantly greater reduction of tyrosine hydroxylase immunoreactivity in the medial striatum, a proportionally greater depletion of dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the striatum, and a greater increase in activated microglia in the substantia nigra than wild-type mice. At 12 months of age, methamphetamine-treatedGDNF+/−mice exhibited less motor activity and lower levels of tyrosine hydroxylase-immunoreactivity, dopamine, DOPAC, and serotonin than wild-type mice. Greater striatal dopamine transporter activity inGDNF+/−mice may underlie their differential response to methamphetamine. These data suggest the possibility that methamphetamine use in young adults, when combined with lower levels of GDNF throughout life, may precipitate the appearance of parkinsonian-like behaviors during aging.
Social Stress Enhances Sympathetic Innervation of Primate Lymph Nodes: Mechanisms and Implications for Viral Pathogenesis
Authors: Sloan Erica K. , Capitanio John P. , Tarara Ross P. , Mendoza Sally P. , Mason William A. , Cole Steve W.
Published: August 2007

Behavioral processes regulate immune system function in part via direct sympathetic innervation of lymphoid organs, but little is known about the factors that regulate the architecture of neural fibers in lymphoid tissues. In the present study, we find that experimentally imposed social stress can enhance the density of catecholaminergic neural fibers within axillary lymph nodes from adult rhesus macaques. This effect is linked to increased transcription of the key sympathetic neurotrophin nerve growth factor and occurs predominately in extrafollicular regions of the paracortex that contain T-lymphocytes and macrophages. Functional consequences of stress-induced increases in innervation density include reduced type I interferon response to viral infection and increased replication of the simian immunodeficiency virus. These data reveal a surprising degree of behaviorally induced plasticity in the structure of lymphoid innervation and define a novel pathway by which social factors can modulate immune response and viral pathogenesis.
Inositol Triphosphate-Mediated Ca2+Signals Direct Purinergic P2Y Receptor Regulation of Neuronal Ion Channels
Authors: Zaika Oleg , Tolstykh Gleb P. , Jaffe David B. , Shapiro Mark S.
Published: August 2007

Purinergic P2Y receptors are one of four types of Gq/11-coupled receptors in rat superior cervical ganglia (SCG) sympathetic neurons. In cultured SCG neurons, purinergic and bradykinin suppression ofIMwere similar in magnitude and somewhat less than that by muscarinic agonists. The effects of the P2Y receptor agonist UTP on neuronal excitability and discharge properties were studied. Under current clamp, UTP increased action potential (AP) firing in response to depolarizing current steps, depolarized the resting potential, decreased the threshold current required to fire an AP, and decreased spike-frequency adaptation. These effects were very similar to those resulting from bradykinin stimulation and not as profound as from muscarinic stimulation or full M-current blockade. We then examined the P2Y mechanism of action. Like bradykinin, but unlike muscarinic, purinergic stimulation induced rises in intracellular [Ca2+]i. Tests using expression of IP3“sponge” or IP3phosphatase constructs implicated IP3accumulation as necessary for purinergic suppression ofIM. Overexpression of wild-type or dominant-negative calmodulin (CaM) implicated Ca2+/CaM in the purinergic action. Both sets of results were similar to bradykinin, and opposite to muscarinic, suppression. We also examined modulation of Ca2+channels. As for bradykinin, purinergic stimulation did not suppressICa, unless neuronal calcium sensor-1 (NCS-1) activity was blocked by a dominant-negative NCS-1 construct. Our results indicate that P2Y receptors modulate M-type channels in SCG cells via IP3-mediated [Ca2+]isignals in concert with CaM and not by depletion of phosphatidylinositol-4, 5-biphosphate. We group purinergic P2Y and bradykinin B2receptors together as having a common mode of action.
Dominant-Negative Inhibition of M-Like Potassium Conductances in Hair Cells of the Mouse Inner Ear
Authors: Holt Jeffrey R. , Stauffer Eric A. , Abraham David , Géléoc Gwenaëlle S. G.
Published: August 2007

Sensory hair cells of the inner ear express multiple physiologically defined conductances, including mechanotransduction, Ca2+, Na+, and several distinct K+conductances, all of which are critical for normal hearing and balance function. Yet, the molecular underpinnings and their specific contributions to sensory signaling in the inner ear remain obscure. We sought to identify hair-cell conductances mediated by KCNQ4, which, when mutated, causes the dominant progressive hearing loss DFNA2. We used the dominant-negative pore mutation G285S and packaged the coding sequence of KCNQ4 into adenoviral vectors. We transfected auditory and vestibular hair cells of organotypic cultures generated from the postnatal mouse inner ear. Cochlear outer hair cells and vestibular type I cells that expressed the transfection marker, green fluorescent protein, and the dominant-negative KCNQ4 construct lacked the M-like conductances that typify nontransfected control hair cells. As such, we conclude that the M-like conductances in mouse auditory and vestibular hair cells can include KCNQ4 subunits and may also include KCNQ4 coassembly partners. To examine the function of M-like conductances in hair cells, we recorded from cells transfected with mutant KCNQ4 and injected transduction current waveforms in current-clamp mode. Because the M-like conductances were active at rest, they contributed to the very low potassium-selective input resistance, which in turn hyperpolarized the resting potential and significantly attenuated the amplitude of the receptor potential. Modulation of M-like conductances may allow hair cells the ability to control the amplitude of their response to sensory stimuli.
Regulation of Neurite Growth by Spontaneous Ca2+Oscillations in Astrocytes
Authors: Kanemaru Kazunori , Okubo Yohei , Hirose Kenzo , Iino Masamitsu
Published: August 2007

Astrocytes play a pivotal role in the regulation of neurite growth, but the intracellular signaling mechanism in astrocytes that mediates this regulation remains unclarified. We studied the relationship between spontaneous Ca2+oscillations in astrocytes and the astrocyte-mediated neurite growth. We generated Ca2+signal-deficient astrocytes in which spontaneous Ca2+oscillations were abolished by a chronic inhibition of IP3signaling. When hippocampal neurons were cultured on a monolayer of Ca2+signal-deficient astrocytes, the growth of dendrites and axons was inhibited. Time-lapse imaging of the advancement of axonal growth cones indicated the involvement of membrane-bound molecules for this inhibition. Among six candidate membrane-bound molecules that may modulate neuronal growth, N-cadherin was downregulated in Ca2+signal-deficient astrocytes. Although a blocking antibody to N-cadherin suppressed the axonal growth on control astrocytes, extrinsic N-cadherin expression rescued the suppressed axonal growth on Ca2+signal-deficient astrocytes. These findings suggest that spontaneous Ca2+oscillations regulate the astrocytic function to promote neurite growth by maintaining the expression of specific growth-enhancing proteins on their surface, and that N-cadherin is one of such molecules.
Spawning and Movement Behavior of Migratory Coastal Cutthroat Trout on the Western Copper River Delta, Alaska
Authors: Saiget D. A. , Sloat M. R. , Reeves G. H.
Published: August 2007

We studied the movement patterns of migratory coastal cutthroat trout Oncorhynchus clarkii clarkii in the western Copper River delta, Alaska, near the northern extent of the subspecies' distribution. Life history information for coastal cutthroat trout is scarce within this region. Movement of coastal cutthroat trout was monitored from 1994 to 1996 with radiotelemetry and tag–recapture of fish at a two-way fishweir. Radio-tracking of 20 adults was conducted for a period ranging from 5 to 343 d. We observed anadromous and potamodromous migrations by fish that were morphologically indistinguishable and spanned a similar size range (mean fork length = 364 mm). Within these migratory groups, fish exhibited variation in movement patterns, including the timing of entry to spawning streams and postspawning movements. Anadromous and potamodromous fish entered study streams either during fall to overwinter and then spawn or during the spring just before spawning. Spawning was most concentrated in the upper portions of the study streams and occurred upstream to the highest available areas. Postspawning movements of potamodromous fish consisted of small-scale (<2 km) movement within the spawning stream or longer movements to larger rivers or lakes. Anadromous fish migrated to estuarine or marine habitat after spawning. Both anadromous and potamodromous fish moved to lentic freshwater habitat to overwinter. Our results provide empirical evidence for an array of life histories displayed by coastal cutthroat trout in south-central Alaska. We attribute the variety of movement patterns, at least in part, to the diverse assemblage of available habitat and seasonally abundant food resources provided by Pacific salmon Oncorhynchus spp. Future management should maintain the quality of and connectivity between reproductive, trophic, and refuge habitats distributed throughout the western Copper River delta.
Spawning Characteristics of Adfluvial Rainbow Trout in a North Idaho Stream: Implications for Error in Redd Counts
Authors: Holecek Dean E. , Walters Jody P.
Published: August 2007

We examined redd microhabitat characteristics of an adfluvial population of rainbow trout Oncorhynchus mykiss in Trail Creek, a third-order tributary to Deep Creek in the Kootenai River drainage, Idaho. We also monitored timing of spawning in relation to stream temperature and discharge. A total of 103 suspected redds were found; 51 of these were measured and checked for the presence of eggs. Thirty-four were actual redds (contained eggs), while 17 were test digs that did not contain eggs. Rainbow trout began spawning on 14 April 2005, 13 d after peak discharge (1.9 m3/s), as mean daily temperature exceeded 4.0°C. Redds had a mean area of 1.19 m2 (SD = 0.62; range = 0.27–2.40 m2), a mean water depth at the pit head of 0.18 m (SD = 0.08; range = 0.05–0.38 m), and a mean water velocity at the pit head of 0.39 m/s (SD = 0.15; range = 0.08–0.67 m/s). Area, total length, and width were the only microhabitat variables that differed statistically between redds and test digs; the mean area of the test digs was 0.72 m2 (SD = 0.67; range = 0.22–2.60 m2). However, the ranges of microhabitat measurements for redds and test digs overlapped; therefore, distinguishing redds from test digs based solely on size, without verifying the presence of eggs, is unlikely. These data could be used to help guide spawning habitat enhancement projects or to create or quantify spawning habitat for adfluvial rainbow trout. The presence of an appreciable number of test digs indicates that redd counts should not be considered a surrogate for numbers of spawning adfluvial rainbow trout; additionally, our results have implications for the use of redd counts to monitor other adult salmonid populations.
Length and Weight Reduction in Larval and Juvenile Yellow Perch Preserved with Dry Ice, Formalin, and Ethanol
Authors: Paradis Yves , Magnan Pierre , Brodeur Philippe , Mingelbier Marc
Published: August 2007

Due to the increasing interest in biochemical indices such as the RNA–DNA ratio used to measure fish growth, fish often need to be stored frozen with dry ice (i.e., −80°C). The objectives of this study were to (1) quantify the effects of dry ice on both the length and weight of larval and juvenile yellow perch Perca flavescens preserved for storage periods of 15 d and 7–8 months, (2) compare these effects with those of two commonly used preservatives (a 10% solution of formalin and a 75% solution of ethanol), and (3) provide equations to convert the lengths and weights of larval and juvenile yellow perch preserved with dry ice, formalin, and ethanol back to their initial unpreserved values. For all preservation methods, fish weight was more affected than length. The smallest length reduction was observed with formalin (short term: 2.1% and 0.1% for larvae and juveniles, respectively; long term: 10.1% and 1.2%), followed by dry ice (short term: 4.0% and 1.4%; long term: 7.2% and 3.9%) and ethanol (short term: 9.6% and 1.2%; long term: 11.7% and 1.2%). The smallest weight reduction was also observed with formalin (short term: 21.9% and 2.2%; long term: 23.2% and 3.9%), followed by dry ice (short term: 54.0% and 11.1%; long term: 52.8% and 8.4%) and ethanol (short term: 61.1% and 22.0%; long term: 66.0% and 26.0%). Except for one case, all of the regression equations that were built to convert the lengths and weights of larval and juvenile yellow perch preserved with dry ice, formalin, and ethanol back to initial measurements were highly significant.
A Basinwide Perspective on Entrainment of Fish in Irrigation Canals
Authors: Carlson Andrew J. , Rahel Frank J.
Published: August 2007

Entrainment in irrigation canals has been considered a major source of mortality for some fish populations. However, the magnitude of fish loss from entrainment is usually not evaluated from a basinwide perspective, thus precluding an assessment of population‐level consequences. We incorporated such a perspective in evaluating entrainment losses of Bonneville cutthroat trout Oncorhynchus clarkii utah and brown trout Salmo trutta in a southwestern Wyoming river basin that is used for irrigating agricultural crops. We estimated the number of Bonneville cutthroat trout and brown trout (>150 mm TL) entrained in irrigation canals and then compared these numbers to population estimates within the river main stem and across the entire basin. We also examined previous studies to determine annual mortality rates for assessment of realized losses to irrigation canals. Small percentages of the Bonneville cutthroat trout (1.2‐3.3%) and brown trout (0.4‐1.2%) populations within the basin were entrained in 2004 and 2005. These values were much lower than the total annual mortality rates for inland riverine cutthroat trout O. clarkii (57.4%) and brown trout (56.4%) in the mountain west region of the United States. Examining the number of entrained fish in context with the basinwide population and total annual mortality allows evaluation of the significance of fish entrainment losses to irrigation canals.
Presence of Seeds in the Planetary Boundary Layer: Some Earlier Records
Authors: Parsons Robert F.
Published: August 2007

A recent paper (Shields et al. 2006) reports trapping seed of horseweed in the planetary boundary layer (PBL) of the lower atmosphere at heights up to 140 m above ground level. While it claims that seeds have not been trapped from the PBL before, it is shown here that seeds of other weedy composites were trapped at altitudes up to 610 m above ground level in southern Australia more than 40 yr ago.
Environmental contaminants in bald eagle eggs from the Aleutian archipelago
Authors: Anthony Robert G. , Miles A. Keith , Ricca Mark A. , Estes James A.
Published: August 2007

We collected 136 fresh and unhatched eggs from bald eagle (Haliaeetus leucocephalus) nests and assessed productivity on eight islands in the Aleutian archipelago, 2000 to 2002. Egg contents were analyzed for a broad spectrum of organochlorine (OC) contaminants, mercury (Hg), and stable isotopes of carbon (δ13C) and nitrogen (δ15N). Concentrations of polychlorinated biphenyls (∑PCBs), p,p'-dichlorodiphenyldichloroethylene (DDE), and Hg in bald eagle eggs were elevated throughout the archipelago, but the patterns of distribution differed among the various contaminants. Total PCBs were highest in areas of past military activities on Adak and Amchitka Islands, indicating local point sources of these compounds. Concentrations of DDE and Hg were higher on Amchitka Island, which was subjected to much military activity during World War II and the middle of the 20th century. Concentrations of ∑PCBs also were elevated on islands with little history of military activity (e.g., Amlia, Tanaga, Buldir), suggesting non–point sources of PCBs in addition to point sources. Concentrations of DDE and Hg were highest in eagle eggs from the most western Aleutian Islands (e.g., Buldir, Kiska) and decreased eastward along the Aleutian chain. This east-to-west increase suggested a Eurasian source of contamination, possibly through global transport and atmospheric distillation and/or from migratory seabirds. Eggshell thickness and productivity of bald eagles were normal and indicative of healthy populations because concentrations of most contaminants were below threshold levels for effects on reproduction. Contrary to our predictions, contaminant concentrations were not correlated with stable isotopes of carbon (δ13C) or nitrogen (δ15N) in eggs. These latter findings indicate that contaminant concentrations were influenced more by point sources and geographic location than trophic status of eagles among the different islands.
Toxicity of nitrogenous fertilizers to eggs of snapping turtles (Chelydra serpentina) in field and laboratory exposures
Authors: de Solla Shane Raymond , Martin Pamela Anne
Published: August 2007

Many reptiles oviposit in soil of agricultural landscapes. We evaluated the toxicity of two commonly used nitrogenous fertilizers, urea and ammonium nitrate, on the survivorship of exposed snapping turtle (Chelydra serpentina) eggs. Eggs were incubated in a community garden plot in which urea was applied to the soil at realistic rates of up to 200 kg/ha in 2004, and ammonium nitrate was applied at rates of up to 2,000 kg/ha in 2005. Otherwise, the eggs were unmanipulated and were subject to ambient temperature and weather conditions. Eggs were also exposed in the laboratory in covered bins so as to minimize loss of nitrogenous compounds through volatilization or leaching from the soil. Neither urea nor ammonium nitrate had any impact on hatching success or development when exposed in the garden plot, despite overt toxicity of ammonium nitrate to endogenous plants. Both laboratory exposures resulted in reduced hatching success, lower body mass at hatching, and reduced posthatching survival compared to controls. The lack of toxicity of these fertilizers in the field was probably due to leaching in the soil and through atmospheric loss. In general, we conclude that nitrogenous fertilizers probably have little direct impacts on turtle eggs deposited in agricultural landscapes.
Time- and concentration-dependent metabolic and genomic responses to exposure to resin acids in brown trout (Salmo truttam.lacustris)
Authors: Meriläinen Päivi S. , Krasnov Aleksei , Oikari Aimo
Published: August 2007

The presence of metabolically conjugated resin acids (RAs) in the bile is considered to be a sensitive indicator for exposure of fish to pulp and paper industry effluents; however, to our knowledge, no comprehensive kinetic study of this response has been made. Juvenile brown trout (Salmo trutta m. lacustris) were exposed to a waterborne mixture of seven RAs (wood rosin) in time (0.1–192.0 h; average concentration, 8 μg/L) and dose (average concentrations, 0, 0.6, 4, 14, and 78 μg/L; 10 d) series, and total RAs were analyzed in bile. In time-dependent exposure, total RAs in bile increased up to 24 h. In concentration-dependent exposure, RAs increased along with the concentration of RAs in water, revealing a high-capacity biotransformation and elimination system in trout liver. In concentration-dependent exposures, the effects on the hepatic transcriptome was studied using a high-density cDNA microarray, and dose-dependent changes were found in a large number of genes. Resin acids interfered with iron metabolism, as evidenced by the decrease in transcripts for iron transporters and heme-containing proteins. Expression of genes encoding for enzymes degrading reactive oxygen species also decreased. Coordinated down-regulation of the protein biosynthesis machinery could result from inhibition of the energy metabolism. A number of changes in gene expression indicated recovery and remodeling of hepatic tissues. We conclude that analysis of total RAs in the bile provides a sensitive and quantitative tool for assessing the exposure of fish to waterborne RAs, whereas multiple gene expression analyses are able to elucidate simultaneous cellular functions for use as potential biomarkers of RAs.