bluuebunny/crossref_metadata_2025_split huggingface dataset:
The flow of Atlantic water to the North Icelandic Shelf and its relation to the drift of cod larvae
Authors: Jónsson Steingrímur , Valdimarsson Héðinn 
Published: August 2005

Abstract
The amount of Atlantic water (AW) present on the shelf north of Iceland is highly variable and influences the local biological productivity. Estimates of the volume and heat transports of AW to the North Icelandic Shelf between 1994 and 2000 are presented here. On average, 66% of the eastward flow on the Hornbanki section consists of AW with a transport of AW of approximately 0.75 Sv. The associated heat transport is 19 TW. There are large interannual variations in the transports, from over 1 Sv in the summers of 1997, 1999, and 2000 to almost no AW transport in February/March 1995. The seasonal variation in the transport has an amplitude of 0.2 Sv with a minimum in February/March and maximum during late spring and summer. Larval cod are carried by this flow from the main spawning grounds south of Iceland to the nursery grounds on the North Icelandic Shelf. The increasing abundance and the better condition of cod larvae after 1997 are related to the increase of the AW inflow then.
Functional Conservation of PISTILLATA Activity in a Pea Homolog Lacking the PI Motif
Authors: Berbel Ana , Navarro Cristina , Ferrándiz Cristina , Cañas Luis Antonio , Beltrán José-Pío , Madueño Francisco 
Published: August 2005

Abstract
Current understanding of floral development is mainly based on what we know from Arabidopsis (Arabidopsis thaliana) and Antirrhinum majus. However, we can learn more by comparing developmental mechanisms that may explain morphological differences between species. A good example comes from the analysis of genes controlling flower development in pea (Pisum sativum), a plant with more complex leaves and inflorescences than Arabidopsis and Antirrhinum, and a different floral ontogeny. The analysis of UNIFOLIATA (UNI) and STAMINA PISTILLOIDA (STP), the pea orthologs of LEAFY and UNUSUAL FLORAL ORGANS, has revealed a common link in the regulation of flower and leaf development not apparent in Arabidopsis. While the Arabidopsis genes mainly behave as key regulators of flower development, where they control the expression of B-function genes, UNI and STP also contribute to the development of the pea compound leaf. Here, we describe the characterization of P. sativum PISTILLATA (PsPI), a pea MADS-box gene homologous to B-function genes like PI and GLOBOSA (GLO), from Arabidopsis and Antirrhinum, respectively. PsPI encodes for an atypical PI-type polypeptide that lacks the highly conserved C-terminal PI motif. Nevertheless, constitutive expression of PsPI in tobacco (Nicotiana tabacum) and Arabidopsis shows that it can specifically replace the function of PI, being able to complement the strong pi-1 mutant. Accordingly, PsPI expression in pea flowers, which is dependent on STP, is identical to PI and GLO. Interestingly, PsPI is also transiently expressed in young leaves, suggesting a role of PsPI in pea leaf development, a possibility that fits with the established role of UNI and STP in the control of this process.
Dedifferentiation of Tobacco Cells Is Associated with Ribosomal RNA Gene Hypomethylation, Increased Transcription, and Chromatin Alterations
Authors: Koukalova Blazena , Fojtova Miloslava , Lim Kar Yoong , Fulnecek Jaroslav , Leitch Andrew Rowland , Kovarik Ales 
Published: August 2005

Abstract
Epigenetic changes accompanying plant cell dedifferentiation and differentiation are reported in 35S ribosomal DNA (rDNA) of tobacco (Nicotiana tabacum). There was a reduction of CG and CNG methylation in both intergenic and genic regions of the rDNA cistron in fully dedifferentiated callus and root compared to leaf. The rDNA hypomethylation was not random, but targeted to particular rDNA gene families at units that are clustered within the tandem array. The process of hypomethylation was initiated as early as 2 weeks after the callus induction and established epigenetic patterns were stably maintained throughout prolonged culture. However, regenerated plants and their progeny showed partial and complete remethylation of units, respectively. Nuclear run-on assays revealed a 2-fold increase of primary (unprocessed) ribosomal RNA transcripts in callus compared to leaf tissue. However, the abundance of mature transcripts in callus was elevated by only about 25%. Fluorescence in situ hybridization analysis of interphase nuclei showed high levels of rDNA chromatin condensation in both callus and leaf, with substantially less decondensed rDNA than is observed in meristematic root-tip cells. It is likely that the regions of the rDNA locus showing decondensation correspond to the clusters of hypomethylated units that occur in the tandem array at each locus. The data together indicate that the establishment of pluripotency and cell proliferation occurring with callus induction is associated with enhanced ribosomal RNA gene expression and overall rDNA hypomethylation, but is not associated with material-enhanced relaxation of chromatin structure (decondensation) at rDNA loci.
Differential Expression of the Arabidopsis Cytochrome c Genes Cytc-1 and Cytc-2. Evidence for the Involvement of TCP-Domain Protein-Binding Elements in Anther- and Meristem-Specific Expression of the Cytc-1 Gene
Authors: Welchen Elina , Gonzalez Daniel H. 
Published: August 2005

Abstract
The promoters of the Arabidopsis (Arabidopsis thaliana) cytochrome c genes, Cytc-1 and Cytc-2, were analyzed using plants transformed with fusions to the β-glucuronidase coding sequence. Histochemical staining of plants indicated that the Cytc-1 promoter directs preferential expression in root and shoot meristems and in anthers. In turn, plants transformed with the Cytc-2 promoter fusions showed preferential expression in vascular tissues of cotyledons, leaves, roots, and hypocotyls, and also in anthers. Quantitative measurements in extracts prepared from different organs suggested that expression of Cytc-1 is higher in flowers, while that of Cytc-2 is higher in leaves. The analysis of a set of deletions and site-directed mutants of the Cytc-1 promoter indicated that a segment located between −147 and −156 from the translation start site is required for expression and that site II elements (TGGGCC/T) located in this region, coupled with a downstream internal telomeric repeat (AAACCCTAA), are responsible for the expression pattern of this gene. Proteins present in cauliflower nuclear extracts, as well as a recombinant protein from the TCP-domain family, were able to specifically bind to the region required for expression. We propose that expression of the Cytc-1 gene is linked to cell proliferation through the elements described above. The fact that closely located site II motifs are present in similar locations in several genes encoding proteins involved in cytochrome c-dependent respiration suggests that these elements may be the target of factors that coordinate the expression of nuclear genes encoding components of this part of the mitochondrial respiratory chain.
Social context modulates behavioural and brain immediate early gene responses to sound in male songbird
Authors: Vignal Clémentine , Andru Julie , Mathevon Nicolas 
Published: August 2005

AbstractAlthough it is well known that brain sensory information processing is a highly modulated phenomenon, how this brain function is shaped by experience and social context remains a question to explore. In this paper, we present the first attempt to investigate this problem using a songbird acoustic communication paradigm. Social context is well known to influence acoustic communicating behaviours in birds. The present paper investigates whether brain processing of auditory inputs can be modulated by this ‘audience effect’. Given that call‐based communication is known to be highly context‐dependent, we focused on the response of male zebra finches (Taeniopygia guttata) to female calls. We tested to see if the current social context surrounding the hearing bird can modify a sound‐induced immediate early gene (IEG) activation in the specific region of the caudomedial nidopallium (NCM), a songbird brain analogous to the superficial layers of the mammalian primary auditory cortex. Our results show that the expression of the sound‐induced immediate early geneZENKin the NCM is considerably enhanced when the hearing bird is in the presence of conspecifics, compared to when he is alone. This context‐dependent increase of a sound‐induced immediate early gene expression can be correlated with the differential behavioural response of males to the playback of the same acoustic stimulus as a function of social context.
Developmental downregulation of P2X3 receptors in motoneurons of the compact formation of the nucleus ambiguus
Authors: Brosenitsch Teresa A. , Adachi Tadafumi , Lipski Janusz , Housley Gary D. , Funk Gregory D. 
Published: August 2005

AbstractMotoneurons of the compact division of the nucleus ambiguus (cNA) are the final output neurons of the swallowing pattern generator. Thus, their normal function is critical to neonatal survival. To explore the role of purinergic signaling in modulating the excitability of these motoneurons during development, immunohistochemical and whole‐cell recording techniques were used to characterize expression patterns of ionotropic P2X receptors and the effects of ATP on cNA motoneurons. Medullary slices containing the cNA were prepared from neonatal (P0–4) and juvenile (P15–21) rats. In neonatal cNA motoneurons, local application of 1 mm ATP produced a large (−133 ± 17 pA; n = 78), desensitizing, inward current that was mimicked by 1 mmα,βmeATP and 2meSATP, and inhibited by the P2 antagonist, PPADS (5 µm), and the P2X3 antagonist, A‐317481 (0.1–1 mm). In juvenile cNA motoneurons, 1 mm ATP produced negligible currents, while 10 mm ATP produced small (−59 ± 14 pA; n = 42), primarily non‐desensitizing currents. Immunohistochemistry demonstrated that in the neonate, the expression of P2X3 was robust, P2X2 and P2X5 moderate, P2X4 and P2X6 weak, and P2X1 absent. In the juvenile cNA, only low levels of P2X5 and P2X6 labeling were detected. These data indicate that P2X receptors in cNA motoneurons are profoundly downregulated during the first two postnatal weeks, and suggest a role for the purinoceptor system, particularly P2X3 receptors, in the control of esophageal motor networks during early postnatal periods.
Dopamine‐dependent and dopamine‐independent actions of cocaine as revealed by brain thermorecording in freely moving rats
Authors: Kiyatkin Eugene A. , Brown P. Leon 
Published: August 2005

AbstractBrain temperature fluctuates biphasically in response to repeated, intravenous (i.v.) cocaine injections, perhaps reflecting cocaine's inhibiting effect on both dopamine (DA) transporters and Na+ channels. By using a DA receptor blockade, one could separate these actions and determine the role of DA‐dependent and DA‐independent mechanisms in mediating this temperature fluctuation. Rats were chronically implanted with thermocouple probes in the brain, a non‐locomotor head muscle and subcutaneously. Temperature fluctuations associated with ten repeated i.v. cocaine injections (1 mg/kg with 8‐min inter‐injection intervals) were examined after a combined, systemic administration of selective D1‐like and D2‐like receptor blockers (SCH‐23390 and eticlopride) at doses that effectively inhibit DA transmission. In contrast to the initial temperature increases and subsequent biphasic fluctuations (decreases followed by increases) seen with repeated cocaine injections in saline‐treated control, brain and muscle temperatures during DA receptor blockade decreased with each repeated cocaine injection. DA receptor blockade had no effects on skin temperature, which tonically decreased and biphasically fluctuated (decreases followed by increases) during repeated cocaine injections in both conditions. DA receptor blockade by itself slightly increased brain and muscle temperatures, with no evident effect on skin temperature. DA antagonists also strongly decreased spontaneous movement activity and completely blocked the locomotor activation normally induced by repeated cocaine injections. Although our data confirm that cocaine's inhibitory action on presynaptic DA uptake is essential for its ability to induce metabolic and behavioral activation, they also suggest that the physiological effects of this drug cannot be explained through this system alone. The continued hypothermic effect of cocaine points to its action on other central systems (particularly blockade of Na+ channels) that may be important for the development of cocaine abuse and adverse effects of this drug.
Mono‐ and dual‐frequency fast cerebellar oscillation in mice lacking parvalbumin and/or calbindin D‐28k
Authors: Servais L. , Bearzatto B. , Schwaller B. , Dumont M. , De Saedeleer C. , Dan B. , Barski J. J. , Schiffmann S. N. , Cheron G. 
Published: August 2005

AbstractCalbindin is a fast Ca2+‐binding protein expressed by Purkinje cells and involved in their firing regulation. Its deletion produced ∼160‐Hz oscillation sustained by synchronous, rhythmic Purkinje cells in the cerebellar cortex of mice. Parvalbumin is a slow‐onset Ca2+‐binding protein expressed in Purkinje cells and interneurons. In order to assess its function in Purkinje cell firing regulation, we studied the firing behavior of Purkinje cells in alert mice lacking parvalbumin (PV–/–), calbindin (CB–/–) or both (PV–/–CB–/–) and in wild‐type controls. The absence of either protein resulted in Purkinje cell firing alterations (decreased complex spike duration and pause, increased simple spike firing rate) that were more pronounced in CB–/– than in PV–/– mice. Cumulative effects were found in complex spike alterations in PV–/–CB–/– mice. PV–/– and CB–/– mice manifested ∼160‐Hz oscillation that was sustained by Purkinje cells firing rhythmically and synchronously along the parallel fiber axis. This oscillation was dependent on GABAA, N‐methyl‐d‐aspartate and gap junction transmission. PV–/–CB–/– mice exhibited a dual‐frequency (110 and 240 Hz) oscillation. The instantaneous spectral densities of both components were inversely correlated. Simple and complex spikes of Purkinje cells were phase‐locked to one of the two oscillation frequencies. Mono‐ and dual‐frequency oscillations presented similar pharmacological properties. These results demonstrate that the absence of the Ca2+ buffers parvalbumin and calbindin disrupts the regulation of Purkinje cell firing rate and rhythmicity in vivo and suggest that precise Ca2+ transient control is required to maintain the normal spontaneous arrhythmic and asynchronous firing pattern of the Purkinje cells.
Extraocular muscle activity, rapid eye movements and the development of active and quiet sleep
Authors: Seelke Adele M. H. , Karlsson Karl Æ. , Gall Andrew J. , Blumberg Mark S. 
Published: August 2005

AbstractRapid eye movements (REMs), traditionally measured using the electrooculogram (EOG), help to characterize active sleep in adults. In early infancy, however, they are not clearly expressed. Here we measured extraocular muscle activity in infant rats at 3 days of age (P3), P8 and P14–15 in order to assess the ontogeny of REMs and their relationship with other forms of sleep‐related phasic activity. We found that the causal relationship between extraocular muscle twitches and REMs strengthened during the first two postnatal weeks, reflecting increased control of the extraocular muscles over eye movements. As early as P3, however, phasic bursts of extraocular muscle twitching occurred in synchrony with twitching in other muscle groups, producing waves of phasic activity interspersed with brief periods of quiescence. Surprisingly, the tone of the extraocular muscles, invisible to standard EOG measures, fluctuated in synchrony with the tone of other muscle groups; focal electrical stimulation within the dorsolateral pontine tegmentum, an area that has been shown to contain wake‐on neurons in P8 rats, resulted in the simultaneous activation of high tone in both nuchal and extraocular muscles. Finally, when state‐dependent neocortical electroencephalographic activity was observed at P14, it had already integrated fully with sleep and wakefulness as defined using electromyographic criteria alone; this finding is not consistent with the notion that active sleep in infants at this age is ‘half‐activated.’ All together, these results indicate exquisite temporal organization of sleep soon after birth and highlight the possible functional implications of homologous activational states in striated muscle and neocortex.
An ancient spliceosomal intron in the ribosomal protein L7a gene (Rpl7a) of Giardia lamblia
Authors: Russell Anthony G , Shutt Timothy E , Watkins Russell F , Gray Michael W 
Published: August 2005

Abstract

Background
Only one spliceosomal-type intron has previously been identified in the unicellular eukaryotic parasite, Giardia lamblia (a diplomonad). This intron is only 35 nucleotides in length and is unusual in possessing a non-canonical 5' intron boundary sequence, CT, instead of GT.

Results
We have identified a second spliceosomal-type intron in G. lamblia, in the ribosomal protein L7a gene (Rpl7a), that possesses a canonical GT 5' intron boundary sequence. A comparison of the two known Giardia intron sequences revealed extensive nucleotide identity at both the 5' and 3' intron boundaries, similar to the conserved sequence motifs recently identified at the boundaries of spliceosomal-type introns in Trichomonas vaginalis (a parabasalid). Based on these observations, we searched the partial G. lamblia genome sequence for these conserved features and identified a third spliceosomal intron, in an unassigned open reading frame. Our comprehensive analysis of the Rpl7a intron in other eukaryotic taxa demonstrates that it is evolutionarily conserved and is an ancient eukaryotic intron.

Conclusion
An analysis of the phylogenetic distribution and properties of the Rpl7a intron suggests its utility as a phylogenetic marker to evaluate particular eukaryotic groupings. Additionally, analysis of the G. lamblia introns has provided further insight into some of the conserved and unique features possessed by the recently identified spliceosomal introns in related organisms such as T. vaginalis and Carpediemonas membranifera.
Procalcitonin-guided antibiotic use versus a standard approach for acute respiratory tract infections in primary care: study protocol for a randomised controlled trial and baseline characteristics of participating general practitioners [ISRCTN73182671]
Authors: Briel Matthias , Christ-Crain Mirjam , Young Jim , Schuetz Philipp , Huber Peter , Périat Pierre , Bucher Heiner C , Müller Beat 
Published: August 2005

Abstract

Background
Acute respiratory tract infections (ARTI) are among the most frequent reasons for consultations in primary care. Although predominantly viral in origin, ARTI often lead to the prescription of antibiotics for ambulatory patients, mainly because it is difficult to distinguish between viral and bacterial infections. Unnecessary antibiotic use, however, is associated with increased drug expenditure, side effects and antibiotic resistance. A novel approach is to guide antibiotic therapy by procalcitonin (ProCT), since serum levels of ProCT are elevated in bacterial infections but remain lower in viral infections and inflammatory diseases.
The aim of this trial is to compare a ProCT-guided antibiotic therapy with a standard approach based on evidence-based guidelines for patients with ARTI in primary care.

Methods/Design
This is a randomised controlled trial in primary care with an open intervention. Adult patients judged by their general practitioner (GP) to need antibiotics for ARTI are randomised in equal numbers either to standard antibiotic therapy or to ProCT-guided antibiotic therapy. Patients are followed-up after 1 week by their GP and after 2 and 4 weeks by phone interviews carried out by medical students blinded to the goal of the trial.
Exclusion criteria for patients are antibiotic use in the previous 28 days, psychiatric disorders or inability to give written informed consent, not being fluent in German, severe immunosuppression, intravenous drug use, cystic fibrosis, active tuberculosis, or need for immediate hospitalisation.
The primary endpoint is days with restrictions from ARTI within 14 days after randomisation. Secondary outcomes are antibiotic use in terms of antibiotic prescription rate and duration of antibiotic treatment in days, days off work and days with side-effects from medication within 14 days, and relapse rate from the infection within 28 days after randomisation.

Discussion
We aim to include 600 patients from 50 general practices in the Northwest of Switzerland. Data from the registry of the Swiss Medical Association suggests that our recruited GPs are representative of all eligible GPs with respect to age, proportion of female physicians, specialisation, years of postgraduate training and years in private practice.
Retroviral superinfection resistance
Authors: Nethe Micha , Berkhout Ben , van der Kuyl Antoinette C 
Published: August 2005

AbstractThe retroviral phenomenon of superinfection resistance (SIR) defines an interference mechanism that is established after primary infection, preventing the infected cell from being superinfected by a similar type of virus. This review describes our present understanding of the underlying mechanisms of SIR established by three characteristic retroviruses: Murine Leukaemia Virus (MuLV), Foamy Virus (FV), and Human Immunodeficiency Virus (HIV). In addition, SIR is discussed with respect to HIV superinfection of humans.MuLV resistant mice exhibit two genetic resistance traits related to SIR. The cellularFv4gene expresses an Env related protein that establishes resistance against MuLV infection. Another mouse gene (Fv1) mediates MuLV resistance by expression of a sequence that is distantly related to Gag and that blocks the viral infection after the reverse transcription step. FVs induce two distinct mechanisms of superinfection resistance. First, expression of the Env protein results in SIR, probably by occupancy of the cellular receptors for FV entry. Second, an increase in the concentration of the viral Bet (Between-env-and-LTR-1-and-2) protein reduces proviral FV gene expression by inhibition of the transcriptional activator protein Tas (Transactivator of spumaviruses). In contrast to SIR in FV and MuLV infection, the underlying mechanism of SIR in HIV-infected cells is poorly understood. CD4 receptor down-modulation, a major characteristic of HIV-infected cells, has been proposed to be the main mechanism of SIR against HIV, but data have been contradictory. Several recent studies report the occurrence of HIV superinfection in humans; an event associated with the generation of recombinant HIV strains and possibly with increased disease progression. The role of SIR in protecting patients from HIV superinfection has not been studied so far.The phenomenon of SIR may also be important in the protection of primates that are vaccinated with live attenuated simian immunodeficiency virus (SIV) against pathogenic SIV variants. As primate models of SIV infection closely resemble HIV infection, a better knowledge of SIR-induced mechanisms could contribute to the development of an HIV vaccine or other antiviral strategies.
The Open Palm and Digit Technique in the Treatment of Dupuytren’s Contracture
Authors: BELTRAN J. E. , JIMENO-URBAN F. , YUNTA A. 
Published: August 2005

The authors have used the open palm and digit technique for Dupuytren’s contracture in fifty-four patients since May, 1973. The procedure consists in making transverse skin incisions on the palm and fingers leaving the wounds open after limited fasciectomy. The results have been surprisingly good due to the elimination of haematoma formation and finger oedema, and the excellent quality of the final scar.