bluuebunny/crossref_metadata_2025 huggingface dataset:
Impairment of the ubiquitin‐proteasome system causes dopaminergic cell death and inclusion body formation in ventral mesencephalic cultures
Authors: McNaught Kevin St P. , Mytilineou Catherine , JnoBaptiste Ruth , Yabut Jocelyn , Shashidharan P. , Jenner Peter , Olanow C. Warren
Published: May 2003

Mutations in α‐synuclein, parkin and ubiquitin C‐terminal hydrolase L1, and defects in 26/20S proteasomes, cause or are associated with the development of familial and sporadic Parkinson's disease (PD). This suggests that failure of the ubiquitin–proteasome system (UPS) to degrade abnormal proteins may underlie nigral degeneration and Lewy body formation that occur in PD. To explore this concept, we studied the effects of lactacystin‐mediated inhibition of 26/20S proteasomal function and ubiquitin aldehyde (UbA)‐induced impairment of ubiquitin C‐terminal hydrolase (UCH) activity in fetal rat ventral mesencephalic cultures. We demonstrate that both lactacystin and UbA caused concentration‐dependent and preferential degeneration of dopaminergic neurons. Inhibition of 26/20S proteasomal function was accompanied by the accumulation of α‐synuclein and ubiquitin, and the formation of inclusions that were immunoreactive for these proteins, in the cytoplasm of VM neurons. Inhibition of UCH was associated with a loss of ubiquitin immunoreactivity in the cytoplasm of VM neurons, but there was a marked and localized increase in α‐synuclein staining which may represent the formation of inclusions bodies in VM neurons. These findings provide direct evidence that impaired protein clearance can induce dopaminergic cell death and the formation of proteinaceous inclusion bodies in VM neurons. This study supports the concept that defects in the UPS may underlie nigral pathology in familial and sporadic forms of PD.
Neurotensin regulates DARPP‐32 Thr34 phosphorylation in neostriatal neurons by activation of dopamine D1‐type receptors
Authors: Matsuyama Seiichiro , Higashi Hideho , Maeda Hisao , Greengard Paul , Nishi Akinori
Published: May 2003

Neurotensin modulates dopaminergic transmission in the nigrostriatal system. DARPP‐32, a dopamine‐ and cAMP‐regulated phosphoprotein of Mr 32 kDa, is phosphorylated on Thr34 by cAMP‐dependent protein kinase, resulting in its conversion into a potent inhibitor of protein phosphatase‐1 (PP 1). Here, we examined the effect of neurotensin on DARPP‐32 Thr34 phosphorylation using mouse neostriatal slices. Neurotensin stimulated DARPP‐32 Thr34 phosphorylation by 4–7‐fold with a K0.5 of ∼50 nm. The effect of neurotensin was antagonized by a combined neurotensin receptor type‐1 (NTR1)/type‐2 (NTR2) antagonist, SR142948. It was not antagonized by a NTR1 antagonist, SR48692 or by a NTR2 antagonist, levocabastine; neither was it antagonized by the two combined. Pretreatment with TTX or cobalt abolished the effect of neurotensin. The effect of neurotensin was antagonized by a dopamine D1 antagonist, SCH23390, and by ionotropic glutamate receptor antagonists, MK801 and CNQX. These results indicate that neurotensin stimulates the release of dopamine from nigrostriatal presynaptic terminals in an NMDA receptor‐ and AMPA receptor‐dependent manner, leading to the increase in DARPP‐32 Thr34 phosphorylation. Neurotensin stimulated the phosphorylation of Ser845 of the AMPA receptor GluR1 subunit in wild‐type mice but not in DARPP‐32 knockout mice. Thus, neurotensin, by stimulating the release of dopamine, activates the dopamine D1‐receptor/cAMP/PKA/DARPP‐32/PP 1 cascade.
Cdk5 phosphorylates p53 and regulates its activity
Authors: Zhang Jianwen , Krishnamurthy Pavan K. , Johnson Gail V. W.
Published: May 2003

Cyclin dependent kinase 5 (Cdk5) is a proline‐direct protein kinase that is most active in the CNS, and has been implicated as a contributing factor in certain neurodegenerative diseases. Further, there is evidence to suggest that Cdk5 may facilitate the progression of apoptosis. However, the mechanisms involved have not been elucidated. The tumor suppressor protein p53, a transcription factor that is regulated by phosphorylation, increases the expression of genes that control growth arrest or cell death. To understand how Cdk5 could facilitate apoptosis, the effects of Cdk5 on p53 activity were examined. In the present study it is shown that in apoptotic PC12 cells the levels of p53 and Cdk5 increase concomitantly. Further, Cdk5/p25 effectively phosphorylates recombinant p53 in vitro. Transient transfection of Cdk5/p25 into cells results in an increase in p53 levels, as well as the expression of the p53‐responsive genes p21 and Bax. Furthermore, evidence is provided that increased Cdk5 activity increases p53 transcriptional activity significantly, suggesting that p53 is modulated in situ by Cdk5. This is the first demonstration that p53 is a substrate of Cdk5, and that Cdk5 can modulate p53 levels and activity.
Effect of GP120 on glutathione peroxidase activity in cortical cultures and the interaction with steroid hormones
Authors: Brooke Sheila M. , McLaughlin John R. , Cortopassi Karen M. , Sapolsky Robert M.
Published: May 2003

GP120 (the protein component of the HIV viral coat) is neurotoxic and may contribute to the cell loss associated with AIDS‐related dementia. Previously, it has been shown in rat cortical mixed cultures that gp120 increased the accumulation of hydrogen peroxide and superoxide, two reactive oxygen species (ROS). We now demonstrate that gp120 increased activity of the key antioxidant glutathione peroxidase (GSPx), presumably as a defensive mechanism against the increased ROS load. Both estrogen and glucocorticoids (GCs), the adrenal steroid released during stress, blunted this gp120 effect on GSPx activity. The similar effects of estrogen and of GCs are superficially surprising, given prior demonstrations that GCs exacerbated and estrogens protected against gp120 neurotoxicity. We find that these similar effects of estrogen and GCs on GSPx regulation arose, in fact, from very different routes, which are commensurate with these prior reports. Specifically, estrogen has demonstrated antioxidant properties that may prevent the ROS increase (therefore acting as a neuroprotective agent) and rendered unnecessary the compensatory GSPx increased activity. To verify this we have added H2O2 to estrogen + gp120‐treated cells, and GSPx activity was increased. However, with addition of H2O2 to GCs + gp120‐treated cells there was no increase in activity. GCs appeared to decrease enzyme production and or activity and therefore under insult conditions ROS levels rose in the cell resulting in increased neurotoxicity. Overexpression of GSPx enzyme via herpes vector system reversed the GCs‐induced loss of enzyme and eliminated the GCs exacerbation of gp120 neurotoxicity.
Functional significance of a highly conserved glutamate residue of the human noradrenaline transporter
Authors: Sucic Sonja , Paczkowski Filip A. , Runkel Fabian , Bönisch Heinz , Bryan‐Lluka Lesley J.
Published: May 2003

The aim of the study was to investigate the role of glutamate residue 113 in transmembrane domain 2 of the human noradrenaline transporter in determining cell surface expression and functional activity. This residue is absolutely conserved in all members of the Na+‐ and Cl–‐dependent transporter family. Mutations to alanine (hE113A), aspartate (hE113D) and glutamine (hE113Q) were achieved by site‐directed mutagenesis and the mutants were expressed in transfected COS‐7 or HEK‐293 cells. Cell surface expression of hE113A and hE113D, but not hE113Q, was markedly reduced compared with wild type, and functional noradrenaline uptake was detected only for the hE113Q mutant. The pharmacological properties of the hE113Q mutant showed very little change compared with wild type, except for a decrease in Vmax values for noradrenaline and dopamine uptake of 2–3‐fold. However, the hE113D mutant showed very marked changes in its properties, compared with wild type, with 82–260‐fold decreases in the affinities of the substrates, noradrenaline, dopamine and MPP+, and increased Na+ affinity for stimulation of nisoxetine binding. The results of the study show that the size and not the charge of the 113 glutamate residue of the noradrenaline transporter seems to be the most critical factor for maintenance of transporter function and surface expression.
Oxygen and glucose deprivation induces mitochondrial dysfunction and oxidative stress in neurones but not in astrocytes in primary culture
Authors: Almeida Angeles , Delgado‐Esteban María , Bolaños Juan P. , Medina José M.
Published: May 2003

In order to investigate the potential neuroprotective role played by glucose metabolism during brain oxygen deprivation, the susceptibility of cultured neurones and astrocytes to 1 h of oxygen deprivation (hypoxia) or oxygen and glucose deprivation (OGD) was examined. OGD, but not hypoxia, promotes dihydrorhodamine 123 and glutathione oxidation in neurones but not in astrocytes reflecting free radical generation in the former cells. A specific loss of mitochondrial complex‐I activity, mitochondrial membrane potential collapse, ATP depletion and necrosis occurred in the OGD neurones, but not in the OGD astrocytes. Furthermore, superoxide anion but not nitric oxide formation was responsible for these effects. OGD decreased neuronal but not astrocytic NADPH concentrations; this was not observed in hypoxia and was independent of superoxide or nitric oxide formation. These results suggest that glucose metabolism would supply NADPH, through the pentose–phosphate pathway, aimed at preventing oxidative stress, mitochondrial damage and neurotoxicity during oxygen deprivation to neural cells.
Hypotension‐induced dopamine release in prefrontal cortex is mediated by local glutamatergic projections at the level of nerve terminals
Authors: Kawahara Yukie , Kawahara Hiroshi , Westerink Ben H. C.
Published: May 2003

In a previous study it was shown that nitroprusside‐induced hypotension strongly enhances the release of dopamine (DA) in the prefrontal cortex (PFC). In the present study we have further investigated the mechanism involved in this effect. Glutamate receptor antagonists were infused into the ventral tegmental area (VTA) or PFC, while DA release was measured in the ipsilateral PFC and hypotension was applied by intravenous infusion of nitroprusside. Infusion into the VTA of neither a NMDA receptor antagonist (CPP), nor a non‐NMDA antagonist (DNQX) affected the hypotension‐induced increase of DA in the PFC. Intracortical infusion of CPP also failed to affect significantly, whereas local infusion of DNQX inhibited the hypotension‐enhanced release of DA dose‐dependently. The stimulation of DA release was relatively small in the VTA as well as in the nucleus accumbens when compared with the response in the PFC. It is concluded that DA released from mesocortical neurons can be modulated by two different mechanisms: first, by glutamate afferents to the VTA that modify the nerve‐impulse flow of DA neurons; and, second, by glutamate afferents to the PFC that act at the level of the DA nerve terminals. The behaviour context (arousal or stress versus hypotension) determines which type of interaction predominates.
Trophic agents that prevent neuronal apoptosis activate calpain and down‐regulate CaMKIV
Authors: Tremper‐Wells Barbara , Mathur Anjili , Beaman‐Hall Carol M. , Vallano Mary Lou
Published: May 2003

CaMKIV is enriched in neuronal nuclei and mediates Ca2+‐dependent survival via transcription factor phosphorylation. Cultured cerebellar granule neurons were used to examine whether distinct modes of Ca2+ signaling differentially modulate CaMKIV expression and function. For long‐term survival, these neurons require 25 mm KCl or NMDA, which stimulates Ca2+ entry through voltage‐sensitive Ca2+ channels or NMDA receptors (NRs). Lower levels of Ca2+ entry through NRs support survival of a neuronal subpopulation grown in 5 mm KCl media. Several effects were demonstrated: (i) sustained exposure to 25 mm KCl or 140 µm NMDA produced CaMKIV down‐regulation, compared to 5 mm KCl cultures; (ii) CaMKIV down‐regulation was attenuated by nifedipine, APV and CaM kinase inhibitors, indicating that it is Ca2+ dependent and reversible; (iii) down‐regulation was both selective for nuclear substrates and calpain‐mediated; (iv) proteolysis was exacerbated by leptomycin B, a nuclear export inhibitor. Although CaMKIV proteolysis by trophic agents seems paradoxical in light of evidence supporting its critical role in survival, the CaMKIV/CREB signal transduction pathway was preserved, as assessed by CaM kinase‐mediated CREB phosphorylation, and the ability of CaM kinase inhibitors to interfere with KCl‐mediated survival. We hypothesize that limited calpain‐mediated proteolysis of CaMKIV is a negative feedback response to the sustained activation of a Ca2+ and CaMKIV signaling pathway by these agents.
Peptidylarginine deiminase: a candidate factor in demyelinating disease
Authors: Moscarello M. A. , Pritzker L. , Mastronardi F. G. , Wood D. D.
Published: May 2003

In earlier studies we demonstrated that an increase in the relative amounts of citrullinated myelin basic protein (MBP) was found in multiple sclerosis (Moscarello et al. 1994). To determine the temporal relationship between the citrullinated MBP and peptidylarginine deiminase (PAD), the enzyme responsible for deiminating arginyl residues in proteins, we studied enzyme activity, enzyme protein, PAD mRNA in a spontaneously demyelinating transgenic mouse model and we correlated the amount of PAD with citrullinated MBP. Both PAD protein as measured in an immunoslot blot method and PAD RNA were elevated. In fractionation studies we showed that the increase in PAD enzyme was due to an increase in the PAD found in membrane fractions and not the soluble PAD (PADII). From our data we concluded that up‐regulation of myelin‐associated PAD was responsible for the increase in citrullinated MBP in our transgenic mice prior to onset of clinical or pathological signs of demyelination. We postulate that a similar mechanism may be responsible for the increase in citrullinated MBP in multiple sclerosis.
Neuroprotection by scatter factor/hepatocyte growth factor and FGF‐1 in cerebellar granule neurons is phosphatidylinositol 3‐kinase/Akt‐dependent and MAPK/CREB‐independent
Authors: Hossain Mir Ahamed , Russell Juliet C. , Gomes Raquel , Laterra John
Published: May 2003

Neuroprotective actions of scatter factor/hepatocyte growth factor (SF/HGF) have not been described. We examined the effects of SF/HGF in comparison to acidic fibroblast growth factor‐1 (FGF‐1) on N‐methyl‐d‐aspartate (NMDA) and quinolinic acid (QUIN)‐induced excitotoxicity in primary cerebellar granule neurons. Exposure to NMDA or QUIN for 24 h resulted in concentration‐dependent cell death (p < 0.001) that was completely attenuated (p < 0.001) by pre‐treatment of cells with SF/HGF (50 ng/mL) or FGF‐1 (40 ng/mL). SF/HGF and FGF‐1 activated both Akt and MAP‐kinase > threefold (p < 0.001). Neither SF/HGF nor FGF‐1 activated cyclic AMP‐response element binding protein (CREB), a downstream target of MAP‐kinase, whereas brain‐derived neurotrophic factor (BDNF) activated both MAP‐kinase and CREB in granule neurons. Neuroprotection against NMDA or QUIN by SF/HGF and FGF‐1 was negated by the addition of LY294002 (10 µm) or wortmannin (100 nm), two distinct inhibitors of phosphatidylinositol 3‐kinase (PI3‐K), but not by the MAP‐kinase kinase (MEK) inhibitor PD98059 (33 µm). Likewise, expression of a dominant‐negative mutant of Akt (Akt‐kd) completely prevented the neuroprotective actions of SF/HGF and FGF‐1. Overexpression of a constitutively activated Akt (Akt‐myr) or wild‐type Akt (wtAkt) attenuated excitotoxic cell death. These data show that both SF/HGF and FGF‐1 protect cerebellar granule neurons against excitotoxicity with similar potency in a PI3‐K/Akt‐dependent and MAP‐kinase/CREB‐independent manner.
Instrumental role of Na+ in NMDA excitotoxicity in glucose‐deprived and depolarized cerebellar granule cells
Authors: Czyż Aneta , Baranauskas Gytis , Kiedrowski Lech
Published: May 2003

In glucose‐deprived cerebellar granule cells, substitution of extracellular Na+ with Li+ or Cs+ prevented N‐methyl‐d‐aspartate (NMDA)‐induced excitotoxicity. NMDA stimulated 45Ca2+ accumulation and ATP depletion in a Na‐dependent manner, and caused neuronal death, even if applied while Na,K‐ATPase was inhibited by 1 mm ouabain. The cells treated with NMDA in the presence of ouabain accumulated sizable 45Ca2+ load but most of them failed to elevate cytosolic [Ca2+] upon mitochondrial depolarization. Na/Ca exchange inhibitor, KB‐R7943, inhibited Na‐dependent and NMDA‐induced 45Ca2+ accumulation but only if Na,K‐ATPase activity was compromised by ouabain. In cells energized by glucose and exposed to NMDA without ouabain, KB‐R7943 reduced NMDA‐elicited ionic currents by 19% but failed to inhibit 45Ca2+ accumulation. It appears that a large part of NMDA‐induced Ca2+ influx in depolarized and glucose‐deprived cells is mediated by reverse Na/Ca exchange. A high level of reverse Na/Ca exchange operation is maintained by a sustained Na+ influx via NMDA channels and depolarization of the plasma membrane. In cells energized by glucose, however, most Ca2+ enters directly via NMDA channels because Na,K‐ATPase regenerating Na+ and K+ concentration gradients prevents Na/Ca exchange reversal. Since under these conditions Na/Ca exchange extrudes Ca2+, its inhibition destabilizes Ca2+ homeostasis.
Akt pathway mediates a cGMP‐dependent survival role of nitric oxide in cerebellar granule neurones
Authors: Ciani Elisabetta , Virgili Marco , Contestabile Antonio
Published: May 2003

Apoptotic death results from disrupting the balance between anti‐apoptotic and pro‐apoptotic cellular signals. The inter‐ and intracellular messenger nitric oxide is known to mediate either death or survival of neurones. In the present work, cerebellar granule cells were used as a model to assess the survival role of nitric oxide and to find novel signal transduction pathways related to this role. It is reported that sustained inhibition of nitric oxide production induces apoptosis in differentiated cerebellar granule neurones and that compounds that slowly release nitric oxide significantly revert this effect. Neuronal death was also reverted by a caspase‐3‐like inhibitor and by a cyclic GMP analogue, thus suggesting that nitric oxide‐induced activation of guanylate cyclase is essential for the survival of these neurones. We also report that the Akt/GSK‐3 kinase system is a transduction pathway related to the survival action of nitric oxide, as apoptosis caused by nitric oxide deprivation is accompanied by down‐regulation of this, but not of other, kinase systems. Conversely, treatments able to rescue neurones from apoptosis also counteracted this down‐regulation. Furthermore, in transfection experiments, overexpression of the Akt gene significantly decreased nitric oxide deprivation‐related apoptosis. These results are the first evidence for a mechanism where endogenous nitric oxide promotes neuronal survival via Akt/GSK‐3 pathway.
5‐Iodo‐A‐85380 binds to α‐conotoxin MII‐sensitive nicotinic acetylcholine receptors (nAChRs) as well as α4β2* subtypes
Authors: Kulak Jennifer M. , Sum Jocelyn , Musachio John L. , McIntosh J. Michael , Quik Maryka
Published: May 2003

Recent work suggests that 5‐iodo‐A‐85380, a radioiodinated analog of the 3‐pyridyl ether A‐85380, represents a promising imaging agent for non‐invasive, in vivo studies of α4β2* nicotinic acetylcholine receptors (nAChRs; *denotes receptors containing the indicated subunits), because of its low non‐specific binding, low in vivo toxicity and high selectivity for α4β2* nAChRs. As an approach to elucidate nAChR subtypes expressed in striatum, we carried out competitive autoradiography in monkey and rat brain using 5‐[125I]iodo‐A‐85380 ([125I]A‐85380) and [125I]α‐conotoxin MII, a ligand that binds with high affinity to α6* and α3* nAChRs, but not to α4β2* nAChRs. Although A‐85380 is reported to be selective for α4β2* nAChRs, we observed that A‐85380 completely inhibited [125I]α‐conotoxin MII binding in rat striatum and that A‐85380 blocked > 90% of [125I]α‐conotoxin MII sites in monkey caudate and putamen. These results suggest that A‐85380 binds to non‐α4β2* nAChRs, including putative α6* nAChRs. Experiments to determine the percentage of [125I]A‐85380 sites that contain α‐conotoxin MII‐sensitive (α6β2*) nAChRs indicate that they represent about 10% of [125I]A‐85380 sites in rodent striatum and about 30% of sites in monkey caudate and putamen. These data are important for identifying alterations in nicotinic receptor subtypes in Parkinson's disease and other basal ganglia disorders both in in vitro and in in vivo imaging studies.
Plaque‐associated disruption of CSF and plasma amyloid‐β (Aβ) equilibrium in a mouse model of Alzheimer's disease
Authors: DeMattos Ronald B. , Bales Kelly R. , Parsadanian Maia , O'Dell Mark A. , Foss Eric M. , Paul Steven M. , Holtzman David M.
Published: May 2003

To better understand amyloid‐β (Aβ) metabolism in vivo, we assessed the concentration of Aβ in the CSF and plasma of APPV717F (PDAPP) transgenic mice, a model that develops age‐dependent Alzheimer's disease (AD)‐like pathology. In 3‐month‐old mice, prior to the development of Aβ deposition in the brain, there was a highly significant correlation between Aβ levels in CSF and plasma. In 9‐month‐old‐mice, an age at which some but not all mice have developed Aβ deposition, there was also a significant correlation between CSF and plasma Aβ; however, the correlation was not as strong as that present in young mice. In further exploring CSF and plasma Aβ levels in 9‐month‐old mice, levels of CSF Aβ were found to correlate highly with Aβ burden. Analysis of the CSF : plasma Aβ ratio revealed a selective two‐fold increase in plaque versus non‐plaque bearing mice, strongly suggesting a plaque‐mediated sequestration of soluble Aβ in brain. Interestingly, in 9‐month‐old mice, a significant correlation between CNS and plasma Aβ was limited to mice lacking Aβ deposition. These findings suggest that there is a dynamic equilibrium between CNS and plasma Aβ, and that plaques create a new equilibrium because soluble CNS Aβ not only enters the plasma but also deposits onto amyloid plaques in the CNS.
Exploring the perspectives of men who self‐harm
Authors: Taylor Ben
Published: May 2003

Self‐harm has become one of the great taboos of our time. In men it is even less acknowledged, accepted and understood than it is in women. This report looks at the almost invisible population of men who self‐harm. Using interviews with men who self‐harm, it explores their experiences and their perspectives on the support and services to which they have access. It draws on these perspectives to identify what professionals, service providers and commissioners can learn from men who self‐harm and proposes ways forward to better meet their needs.
Maternity Satisfaction Studies and Their Limitations: “What Is, Must Still Be Best”
Authors: van Teijlingen Edwin R. , Hundley Vanora , Rennie Ann‐Marie , Graham Wendy , Fitzmaurice Ann
Published: May 2003

ABSTRACT: Background: Health policymakers throughout the developed world are paying close attention to factors in maternity care that may influence women's satisfaction. This paper examines some of these factors in the light of observations from previous studies of satisfaction with health services.

Methods: The Scottish Birth Study, a cross‐sectional questionnaire survey, sought the views of all women in Scotland delivering during a 10‐day period in 1998. A total of 1,137 women completed and returned questionnaires (response rate = 69%).

Results: Women were overwhelmingly satisfied with their prenatal, intrapartum, and postnatal care. As is common in this type of study, reports of dissatisfaction were relatively low. However, differences occurred in satisfaction levels between subgroups; for example, the fewer the number of caregivers the woman had during childbirth, the more likely she was to be satisfied with the care received. A range of factors appeared to influence reported satisfaction levels, such as characteristics of the care provided and the woman's psychosocial circumstances.

Conclusions: In addition to the inherent limitations of satisfaction studies found in the literature, problems may arise if such surveys are used uncritically to shape the future provision of maternity services, because service users tend to value the status quo over innovations of which they have no experience. Therefore, although satisfaction surveys have a role to play, we argue that they should only be used with caution, and preferably as part of an array of tools. (BIRTH 30:2 June 2003)
Neonatal Outcome after Trial of Labor Compared with Elective Repeat Cesarean Section
Authors: Fisler Rita E. , Cohen Amy , Ringer Steven A. , Lieberman Ellice
Published: May 2003

ABSTRACT: Background: Trial of labor after cesarean section has been an important strategy for lowering the rate of cesarean delivery in the United States, but concerns regarding its safety remain. The purpose of this study was to evaluate the outcome of newborns delivered by elective repeat cesarean section compared to delivery following a trial of labor after cesarean.

Methods: All low‐risk mothers with 1 or 2 previous cesareans and no prior vaginal deliveries, who delivered at our institution from December 1994 through July 1995, were identified. Neonatal outcomes were compared between 136 women who delivered by elective repeat cesarean section and 313 women who delivered after a trial of labor. To investigate reasons for differences in outcome between these groups, neonatal outcomes within the trial of labor group were then compared between those mothers who had received epidural analgesia (n = 230) and those who did not (n = 83).

Results: Infants delivered after a trial of labor had increased rates of sepsis evaluation (23.3% vs 12.5%, p = 0.008); antibiotic treatment (11.5% vs 4.4%, p = 0.02); intubation to evaluate for the presence of meconium below the cords (11.5% vs 1.5%, p < 0.001); and mild bruising (8.0% vs 1.5%, p = 0.008). Within the trial of labor group, infants of mothers who received epidural analgesia were more likely to have received diagnostic tests and therapeutic interventions including sepsis evaluation (29.6% vs 6.0%, p = 0.001) and antibiotic treatment (13.9% vs 4.8%, p = 0.03) than within the no‐epidural analgesia group.

Conclusions: Infants born to mothers after a trial of labor are twice as likely to undergo diagnostic tests and therapeutic interventions than infants born after an elective repeat cesarean section, but the increase occurred only in the subgroup of infants whose mothers received epidural analgesia for pain relief during labor. The higher rate of intervention could relate to the well‐documented increase in intrapartum fever that occurs with epidural use. (BIRTH 30:2 June 2003)
Women's Satisfaction with Their Involvement in Health Care Decisions During a High‐Risk Pregnancy
Authors: Harrison Margaret J. , Kushner Kaysi Eastlick , Benzies Karen , Rempel Gwen , Kimak Cathy
Published: May 2003

ABSTRACT: Background: Increasingly, women seek involvement in decisions about their health care. The purpose of this study was to examine women's experience of, and satisfaction with, their involvement in health care decisions during a high‐risk pregnancy.

Methods: Forty‐seven women with hypertension or threatened preterm delivery (including multiple births) were interviewed after the birth of their child. They received prenatal care at home from nurses in a community program or were hospitalized. The in‐depth interviews were audiotaped and transcribed; data were analyzed using constant comparative methods.

Results: Women identified an increased feeling of responsibility for the health of their baby and themselves, but differed in choosing active or passive involvement in health care decisions. Women who wanted active involvement achieved it through one of three processes: struggling for, negotiating, or being encouraged. Women who wanted passive involvement and women facing health crises used the process of trusting in the expertise of nurses and physicians. Women were satisfied if the care from health care professionals was congruent with how they wanted to be involved in decision‐making.

Conclusions: Although most women want to be actively involved in health decision‐making during a high‐risk pregnancy, some prefer a passive role. The setting of prenatal care, community‐based or in‐hospital, was less important than the ability of nurses and physicians to support the woman in her preferred role in decision‐making. (BIRTH 30:2 June 2003)
STRUCTURE AND FUNCTION OF BENTHIC ALGAL COMMUNITIES IN AN EXTREMELY ACID RIVER1
Authors: Sabater Sergi , Buchaca Teresa , Cambra Jaume , Catalan Jordi , Guasch Helena , Ivorra Núria , Muñoz Isabel , Navarro Enrique , Real Montserrat , Romaní Anna
Published: May 2003

The composition of algal species and pigments and the structural and functional characteristics of the algal community were investigated in an acid stream of southwestern Spain, the Río Tinto. The algal community had low diversity and showed few seasonal differences. It was mainly made up of Klebsormidium flaccidum Kütz. (Silva, Mattox & Blackwell) that produced long greenish or purplish filaments, Pinnularia acoricola Hust. (producing brown patches) and Euglena mutabilis Schmitz. The algal filaments made up a consistent biofilm that also included fungal hyphae, iron bacterial sheaths, diatoms, and mineral particles. HPLC analyses on Río Tinto samples showed that undegraded chl accounted for 67% of the total chl in the filamentous patches but were a minority in the brown patch (2.6%). The brown patch had a concentration of carotenoids eight times lower than that observed in the green patch. When chl concentrations were weighted for the proportion of the different patches on the streambed, undegraded chl a accounted for 89.2 mg chl a·m−2 of stream surface area (5.4 g C·m−2). This high algal biomass was supported by relatively high nutrient concentrations and by a high phosphatase activity (Vmax = 137.7 nmol methylumbelliferyl substrate·cm−2·h−1, Km = 0.0045 μM). The remarkable algal biomass in Río Tinto potentially contributed to the bacterial–fungal community and to the macroinvertebrate community and emphasizes the role that the algae may have in the organic matter cycling and energy flow in extreme systems dominated by heterotrophic microorganisms.
PERIPHYTIC DIATOM ASSEMBLAGES FROM ULTRA‐OLIGOTROPHIC AND UV TRANSPARENT LAKES AND PONDS ON VICTORIA ISLAND AND COMPARISONS WITH OTHER DIATOM SURVEYS IN THE CANADIAN ARCTIC1
Authors: Michelutti Neal , Holtham Anita J. , Douglas Marianne S. V. , Smol John P.
Published: May 2003

Periphytic diatoms are potentially powerful indicators of environmental change in climatically‐sensitive high latitude regions. However, only a few studies have examined their taxonomic and ecological characteristics. We identified and enumerated diatom assemblages from sediment, rock, and moss habitats in 34 ultra‐oligotrophic and highly transparent lakes and ponds on Victoria Island, Arctic Canada. The similar limnological characteristics of the sites allowed us to examine the influence of habitat, independent of water chemistry, on the diatom assemblages. As is typical in shallow arctic water bodies, benthic taxa, including species of Achnanthes, Caloneis, Cymbella, Navicula, and Nitzschia, were most widely represented. Minor gradients in our measured environmental variables did not significantly explain any variance in diatom species, but there were marked differences in diatom assemblages among sites. Pond ephemerality seems to explain some diatom variation, because aerophilic taxa such as Achnanthes kryophila Petersen and A. marginulata Grunow were dominant in shallow sites that had undergone appreciable reductions in volume. We identified several taxa that exhibited strong habitat preferences to sediment, moss, or rock substrates and also found significant differences (P < 0.01) in diatom composition among the three habitats. In comparisons with three similar diatom surveys extending over 1200 km of latitude, we determined that surface sediment assemblages differed significantly (P < 0.001) among all regions examined. Diatom species diversity was inversely related to latitude, a result likely explained by differences in the lengths of growing seasons. These data contribute important ecological information on diatom assemblages in arctic regions and will aid in the interpretation of environmental changes in biomonitoring and paleolimnological studies.
RECOVERY AND GENETIC DIVERSITY OF THE INTERTIDAL KELP LESSONIA NIGRESCENS (PHAEOPHYCEAE) 20 YEARS AFTER EL NIÑO 1982/831
Authors: Martínez Enrique A. , Cárdenas Leyla , Pinto Raquel
Published: May 2003

Massive mortality in kelp beds of the Pacific coasts of North and South America was caused by the rise in surface seawater temperature during the El Niño Southern Oscillation (ENSO) event of 1982/83, the strongest in the four and half previous centuries. In northern Chile a stretch of 600 km of coastline showed massive mortality of the intertidal kelp species Lessonia nigrescens Bory, of which only a few individuals managed to survive. Kelps and their associated biodiversity recovered but kelp beds re‐colonization in general was variable in time and space seemingly very slow along northern Chilean coasts. Here we show, effectively, that northward re‐colonization advanced less than 60 km in 20 years. Conversely, kelp beds of the Northern Hemisphere recovered 300 km in only six months after the same ENSO event. Genetic diversity in the two most affected populations of L. nigrescens shows half of the heterozygosity and polymorphism with respect to that observed in six non affected populations. In addition, geographically separated populations seem highly isolated as evidenced by high and significant fixation indices (all FST values over 0.4).
LOW MOLECULAR WEIGHT CARBOHYDRATES OF THE BANGIOPHYCIDAE (RHODOPHYTA)1
Authors: Karsten Ulf , West John A. , Zuccarello Giuseppe C. , Engbrodt Ralph , Yokoyama Akiko , Hara Yoshiaki , Brodie Juliet
Published: May 2003

In the order Porphyridiales there are three clades based on molecular evidence. These show parallels with the low molecular weight carbohydrate (LMWCs) in different genera. Clade Porphyridiales 1 includes Dixoniella, Glaucosphaera, Rhodella, and one undescribed genus (3987) that all contain mannitol. Clade Porphyridiales 2 comprises taxa of the Stylonematales Rhodosorus and Stylonema species and contains digeneaside and sorbitol, whereas Chroodactylon has only sorbitol. In clade Porphyridiales 3 Flintiella, Porphyridium, and the undescribed genus (3797) all possess only floridoside. In the Erythropeltidales Rhodochaete contains floridoside and digeneaside, Erythrotrichia species contain only floridoside, Sahlingia subintegra has floridoside and traces of D‐floridoside, and Smithora has L‐isofloridoside plus floridoside. In the Compsopogonales Boldia and Compsopogon have only floridoside. Within these genera as presently circumscribed, the LMWCs appear to be a reliable character to supplement the usual cytological characters.
Molecular basis for the immunostimulatory activity of guanine nucleoside analogs: Activation of Toll-like receptor 7
Authors: Lee Jongdae , Chuang Tsung-Hsien , Redecke Vanessa , She Liping , Pitha Paula M. , Carson Dennis A. , Raz Eyal , Cottam Howard B.
Published: May 2003

Certain C8-substituted and N7, C8-disubstituted guanine ribonucleosides comprise a class of small molecules with immunostimulatory activity. In a variety of animal models, these agents stimulate both humoral and cellular immune responses. The antiviral actions of these guanosine analogs have been attributed to their ability to induce type I IFNs. However, the molecular mechanisms by which the guanosine analogs potentiate immune responses are not known. Here, we report that several guanosine analogs activate Toll-like receptor 7 (TLR7). 7-Thia-8-oxoguanosine, 7-deazaguanosine, and related guanosine analogs activated mouse immune cells in a manner analogous to known TLR ligands, inducing cytokine production in mouse splenocytes (IL-6 and IL-12, type I and II IFNs), bone marrow-derived macrophages (IL-6 and IL-12), and in human peripheral blood leukocytes (type I IFNs, tumor necrosis factor α and IL-12). The guanosine congeners also up-regulated costimulatory molecules and MHC I/II in dendritic cells. Genetic complementation studies in human embryonic kidney 293 cells confirmed that the guanosine analogs activate cells exclusively via TLR7. The stimulation of TLR7 by the guanosine analogs in human cells appears to require endosomal maturation because inhibition of this process with chloroquine significantly reduced the downstream activation of NF-κB. However, TLR8 activation by R-848 and TLR2 activation by {S-[2,3-bis(palmitoyloxy)-(2-RS)-propyl]-N-palmitoyl-R-Cys-S-Ser-Lys4-OH, trihydrochloride)} were not inhibited by chloroquine, whereas TLR9 activation by CpG oligodeoxynucleotides was abolished. In summary, we present evidence that guanosine analogs activate immune cells via TLR7 by a pathway that requires endosomal maturation. Thus, the B cell-stimulating and antiviral activities of the guanosine analogs may be explained by their TLR7-activating capacity.
Mice lacking dipeptidyl peptidase IV are protected against obesity and insulin resistance
Authors: Conarello Stacey L. , Li Zhihua , Ronan John , Roy Ranabir Sinha , Zhu Lan , Jiang Guoqiang , Liu Franklin , Woods John , Zycband Emanuel , Moller David E. , Thornberry Nancy A. , Zhang Bei B.
Published: May 2003

Dipeptidyl peptidase IV (DP-IV), a member of the prolyl oligopeptidase family of peptidases, is involved in the metabolic inactivation of a glucose-dependent insulinotropic hormone, glucagon-like peptide 1 (GLP-1), and other incretin hormones. Here, we investigated the impact of DP-IV deficiency on body weight control and insulin sensitivity in mice. Whereas WT mice displayed accelerated weight gain and hyperinsulinemia when fed a high-fat diet (HFD), mice lacking the gene encoding DP-IV (DP-IV
-/-
) are refractory to the development of obesity and hyperinsulinemia. Pair-feeding and indirect calorimetry studies indicate that reduced food intake and increased energy expenditure accounted for the resistance to HFD-induced obesity in the DP-IV
-/-
mice. Ablation of DP-IV also is associated with elevated GLP-1 levels and improved metabolic control in these animals, resulting in improved insulin sensitivity, reduced pancreatic islet hypertrophy, and protection against streptozotocin-induced loss of β cell mass and hyperglycemia. Together, these observations suggest that chronic deletion of DP-IV gene has significant impact on body weight control and energy homeostasis, providing validation of DP-IV inhibition as a viable therapeutic option for the treatment of metabolic disorders related to diabetes and obesity.
Cytokines and BCR-ABL mediate suppression of TRAIL-induced apoptosis through inhibition of forkhead FOXO3a transcription factor
Authors: Ghaffari Saghi , Jagani Zainab , Kitidis Claire , Lodish Harvey F. , Khosravi-Far Roya
Published: May 2003

Cytokine-provided survival signals are known to suppress apoptosis through inhibition of mitochondrial pathways that involve Bcl-2 family members. Here we show that in hematopoietic cells, cytokines also regulate death receptor-mediated pathways. We demonstrate that hematopoietic cytokines such as IL-3 and erythropoietin in normal cells, as well as BCR-ABL oncoprotein in transformed cells, inhibit transcription of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Using small interfering RNAs, we show that the inhibition of TRAIL function is sufficient to partially rescue cytokine-deprived cells from apoptosis. Finally, we demonstrate that cytokine and BCR-ABL suppression of TRAIL transcription is mediated through phosphorylation and inhibition of the forkhead FOXO3a transcription factor. BCR-ABL-induced inhibition of TRAIL transcription in hematopoietic cells may provide a novel mechanism for tumorigenicity in chronic myeloid leukemia.
A new
Drosophila
spliceosomal intron position is common in plants
Authors: Tarrío Rosa , Rodríguez-Trelles Francisco , Ayala Francisco J.
Published: May 2003

The 25-year-old debate about the origin of introns between proponents of “introns early” and “introns late” has yielded significant advances, yet important questions remain to be ascertained. One question concerns the density of introns in the last common ancestor of the three multicellular kingdoms. Approaches to this issue thus far have relied on counts of the numbers of identical intron positions across present-day taxa on the assumption that the introns at those sites are orthologous. However, dismissing parallel intron gain for those sites may be unwarranted, because various factors can potentially constrain the site of intron insertion. Demonstrating parallel intron gain is severely handicapped, because intron sequences often evolve exceedingly fast and intron phylogenetic distributions are usually ambiguous, such that alternative loss and gain scenarios cannot be clearly distinguished. We have identified an intron position that was gained independently in animals and plants in the
xanthine dehydrogenase
gene. The extremely disjointed phylogenetic distribution of the intron argues strongly for separate gain rather than recurrent loss. If the observed phylogenetic pattern had resulted from recurrent loss, all observational support previously gathered for the introns-late theory of intron origins based on the phylogenetic distribution of introns would be invalidated.
sal1
determines the number of aleurone cell layers in maize endosperm and encodes a class E vacuolar sorting protein
Authors: Shen Bo , Li Changjiang , Min Zhao , Meeley Robert B. , Tarczynski Mitchell C. , Olsen Odd-Arne
Published: May 2003

A microscopy-based screen of a large collection of maize
Mutator
(
Mu
) transposon lines identified the
supernumerary aleurone layers 1
-
1
(
sal1
-
1
) mutant line carrying up to seven layers of aleurone cells in defective kernel endosperm compared with only a single layer in wild-type grains. Normal, well filled endosperm that is homozygous for the
sal1
-
1
mutant allele contains two to three layers of aleurone cells. Cloning of the
sal1
gene was accomplished by using
Mu
tagging, and the identity of the cloned gene was confirmed by isolating an independent
sal1
-
2
allele by reverse genetics. Homozygous
sal1
-
2
endosperm has two to three layers of aleurone cells in normal, well filled grains.
In situ
hybridization experiments reveal that the
sal1
gene is ubiquitously expressed in vegetative as well as zygotic grain tissues, with no difference being detected between aleurone cells and starchy endosperm cells. Northern blot analysis failed to detect the
sal1
-
2
transcript in leaves of homozygous plants, suggesting that the allele is a true
sal1
knockout allele. The
sal1
gene encodes a homologue of the human
Chmp1
gene, a member of the conserved family of the class E vacuolar protein sorting genes implicated in membrane vesicle trafficking. In mammals, CHMP1 functions in the pathway targeting plasma membrane receptors and ligands to lysosomes for proteolytic degradation. Possible roles for the function of the
sal1
gene in aleurone signaling, including a defect in endosome trafficking, are discussed.
Interaction of antimicrobial peptide protegrin with biomembranes
Authors: Gidalevitz David , Ishitsuka Yuji , Muresan Adrian S. , Konovalov Oleg , Waring Alan J. , Lehrer Robert I. , Lee Ka Yee C.
Published: May 2003

The antimicrobial peptide protegrin-1 (PG-1) interacts with membranes in a manner that strongly depends on membrane lipid composition. In this research we use an approach representing the outer layers of bacterial and red blood cell membranes with lipid monolayers and using a combination of insertion assay, epifluorescence microscopy, and surface x-ray scattering to gain a better understanding of antimicrobial peptide's mechanism of action. We find that PG-1 inserts readily into anionic dipalmitoyl-phosphatidylglycerol, palmitoyl-oleoyl-phosphatidylglycerol, and lipid A films, but significantly less so into zwitterionic dipalmitoyl-phosphatidylcholine, palmitoyl-oleoyl-phosphatidylcholine, and dipalmitoyl-phosphatidylethanolamine monolayers under similar experimental conditions. Epifluorescence microscopy shows that the insertion of PG-1 into the lipid layer results in the disordering of lipid packing; this disordering effect is corroborated by grazing incidence x-ray diffraction data. X-ray reflectivity measurements further point to the location of the peptide in the lipid matrix. In a pathologically relevant example we show that PG-1 completely destabilizes monolayer composed of lipid A, the major component in the outer membrane of Gram-negative bacteria, which is likely to be the mechanism by which PG-1 disrupts the outer membrane, thus allowing it to reach the target inner membrane.
The putative glutamate receptor 1.1 (AtGLR1.1) functions as a regulator of carbon and nitrogen metabolism in
Arabidopsis thaliana
Authors: Kang Jiman , Turano Frank J.
Published: May 2003

The ability to coordinate carbon (C) and nitrogen (N) metabolism enables plants to regulate development and metabolic responses to different environmental conditions. The regulator(s) or sensor(s) that monitor crosstalk between biosynthetic pathways and ultimately control the flow of C or N through them have remained elusive. We used an antisense strategy to demonstrate that the putative glutamate receptor 1.1 (AtGLR1.1) functions as a regulator of C and N metabolism in
Arabidopsis
. Seeds from AtGLR1.1-deficient
Arabidopsis
(
antiAtGLR1.1
) lines did not germinate in the presence of an animal ionotropic glutamate receptor (iGLR) antagonist, but germination was restored upon coincubation with an iGLR agonist or the putative ligand glutamate. In
antiAtGLR1.1
lines, endogenous abscisic acid (ABA) concentrations increased with iGLR antagonist treatments and decreased with coincubation with an iGLR agonist, suggesting that germination was controlled by ABA.
antiAtGLR1.1
seedlings also exhibited sensitivity to increased levels of Ca
2+
compared with wild type, and they exhibited a conditional phenotype that was sensitive to the C:N ratio. In the presence of C, specifically sucrose, but not glucose, mannitol, or sorbitol,
antiAtGLR1.1
seeds did not germinate, but germination was restored upon coincubation with

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\begin{equation*}{\mathrm{NO}}_{3}^{-}\end{equation*}\end{document}

, but not

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. Immunoblot, isoenzyme, and RT-PCR analyses indicate that AtGLR1.1 regulates the accumulation of distinct C- and N-metabolic enzymes, hexokinase 1 (
HXK1
) and zeaxanthin epoxidase (
ABA1
), by transcriptional control. We provide a model to describe the role of AtGLR1.1 in C/N metabolism and ABA biosynthesis, which in turn controls seed germination.