bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diabetes‐induced decrease of adenosine kinase expression impairs the proliferation potential of diabetic rat T lymphocytes
Authors: Sakowicz‐Burkiewicz Monika , Kocbuch Katarzyna , Grden Marzena , Szutowicz Andrzej , Pawelczyk Tadeusz 
Published: May 2006

SummaryThe proliferative response of T lymphocytes is a crucial step in cell‐mediated immunity. This study was undertaken to investigate the mechanisms leading to the impaired proliferative response of diabetic T lymphocytes. T cells that had been isolated from the spleen of normal rats and cultured in medium containing 20 mmglucose and no insulin displayed the same degree of proliferative impairment as cells isolated from diabetic rats. The rate of T‐cell proliferation, when induced with concanavalin A or anti‐CD3 and anti‐CD28 antibodies, was not affected by the inhibition of nucleoside transporters. T cells cultured at high glucose concentrations in the absence of insulin displayed decreased expression of adenosine kinase, and released measurable extracellular quantities of adenosine. Under resting conditions, the level of cAMP was 5·9‐fold higher in these cells compared to cells grown in low glucose and in the presence of insulin. Experiments with specific adenosine receptor agonists and antagonists showed that adenosine‐induced suppression of diabetic T cell proliferation was mediated by the A2Aadenosine receptor, but not by the A2Breceptor. Treatment of diabetic T cells with 10 μmH‐89, a specific protein kinase A inhibitor, restored T‐cell proliferation. These results show that suppressed proliferation of diabetic T lymphocytes is evoked by the decreased expression of adenosine kinase, leading to the outflow of adenosine from the cell. Extracellular adenosine then stimulates the A2Areceptor and induces cAMP production, leading to the activation of protein kinase A, and suppression of T‐cell proliferation.
Differences in SCSA outcome among boars with different sperm freezability
Authors: Hernández Marta , Roca Jordi , Ballester Joan , Vázquez Juan M. , Martínez Emilio A. , Johannisson Anders , Saravia Fernando , Rodríguez‐Martínez Heriberto 
Published: May 2006

SummarySpermatozoa from some boars sustain the process of cryopreservation poorly and yield poor fertility after artificial insemination. Poor freezability has not been disclosed using conventional semen analyses. A defective chromatin can, if present in a substantial number of spermatozoa, affect the fertilizing ability of spermatozoa. Here we tested the hypothesis that nuclear DNA instability could explain differences in freezability among boars, and complement or supersede conventional tests for sperm quality such as sperm motility or membrane assessments. Frozen–thawed (FT) spermatozoa from a total of 44 stud boars were assessed by the sperm chromatin structure assay (SCSA), in relation to computer‐assisted sperm analysis‐derived sperm motility variables and sperm viability (triple fluorescent microscopic staining), including three experiments. The first trial, including 24 boars, evaluated the relationship between the sperm motility and viability with levels of DNA integrity. The SCSA showed that most spermatozoa had intact DNA [levels of DNA fragmentation index (%DFI) ranging from 0.63% to 11.85%] significantly correlated (albeit weakly) with current sperm quality variables. The second trial, on 15 boars, assessed the influence of two different thawing rates (20 s at 37 °C vs. 8 s at 70 °C) and the post‐thaw incubation times (0, 30, 150 and 300 min) at 37 °C on FT‐boar sperm quality. The highest sperm survival (p < 0.05) and the lowest DNA damage (p < 0.01) were achieved when thawing was carried out at 70 °C for 8 s, without any change during the first 150 min of incubation. Finally, the third experiment studied if differences in sperm freezability showed by stud boar semen, as ‘good’ or ‘bad’ freezers by conventional analyses, could be attributed to differences in chromatin structure. All SCSA parameters were low, but significantly (p < 0.05–0.001) higher for ‘bad’ freezers, showing they had less homogeneous sperm chromatin than the ‘good’ freezers. The results indicate that SCSA outcome complements conventional assessment of FT‐boar spermatozoa, disclosing differences in their ability to sustain freezing and thawing. However, the low overall DNA damage observed in FT spermatozoa seems to have poor biological significance.
Local administration of 2% trimecaine affects the content of fucosylated glycoconjugates in goblet cells in rabbit tracheal epithelium
Authors: Vajner Luděk , Uhlík Jiří , Konrádová Václava , Kleščová Andrea , Adášková Jana 
Published: May 2006

SummaryThe proportion of fucosylated glycoconjugate‐containing rabbit tracheal goblet cells after intratracheal application of trimecaine was studied to evaluate its possible unfavourable effects. This lapine model is comparable with diagnostic findings in humans because airway epithelia in humans and rabbits are similar; tracheal epithelium is also practically identical to bronchial epithelium in both species. Local trimecaine anaesthesia caused a proportional decrease in percentage of the tracheal goblet cells containing both α(1–2)‐ and α(1–6)‐, α(1–3)‐ and α(1–4)‐fucosylated glycoconjugates as revealed 10 min postexposure using lectin histochemistry. In previous studies, only mild ultrastructural damage to the airway's epithelium was revealed, but a conspicuous decrease in sialylated glycoconjugate‐containing tracheal goblet cells and the dominance of acidic sulphated glycoconjugates were observed as after‐effects of the same treatment. Glycoconjugate changes can influence the inner environment of airways (e.g. viscoelastic properties of the airways’ mucus and mucosal barrier functions) and thus the patient's defence barriers in airways may be weakened. Concurrently, the histochemical properties of goblet cells can be altered in bronchoscopic specimens. Since trimecaine is widely used as local anaesthesia in airways in bronchoscopy, it is necessary to heed these aforementioned effects.
How best to collect demographic data for population viability analysis models
Authors: MÜNZBERGOVÁ ZUZANA , EHRLÉN JOHAN 
Published: May 2006

Summary
Matrix population models have become important tools in many fields of ecology and conservation biology, and are the most commonly used method in population viability analysis (PVA). There is a large literature concerned with different aspects of matrix model analysis, but relatively little attention has been paid to how data are collected.
In most demographic population viability studies, data are sampled in permanent plots, often resulting in poor representation of some stages. It has been suggested that by using previous knowledge of species’ demography it is possible to sample demographic data more efficiently. Here we propose an alternative method that is much simpler and does not rely on any assumptions, namely sampling an equal number of individuals per stage.
By using demographic data from 32 species we showed that sampling an equal number of individuals per stage provides more precise estimates of both population growth rate and elasticity than the traditional plot‐based method. In some cases it is also better than the estimates gained using the method based on previous knowledge of the species’ demography. The conclusions of the latter method are very sensitive to the quality of the previous knowledge of the species’ demography. In contrast, collecting demographic data from an equal number of individuals per stage is independent of any assumptions.
Synthesis and applications. A central aim for management of threatened species is to develop robust and accurate methods for assessing population viability that are also efficient in terms of costs and labour. A key issue is how to collect the data on which viability assessments are based. We show that it is possible to increase considerably the accuracy and robustness of demographic PVA without increasing sampling effort, by using a simple method based on sampling an equal number of individuals per life‐cycle stage. Improved PVA model performance will be important to guide conservation efforts and to evaluate different management options.
Slowing down a pine invasion despite uncertainty in demography and dispersal
Authors: BUCKLEY YVONNE M. , BROCKERHOFF ECKEHARD , LANGER LISA , LEDGARD NICHOLAS , NORTH HEATHER , REES MARK 
Published: May 2006

Summary
Management decisions regarding invasive plants often have to be made quickly and in the face of fragmentary knowledge of their population dynamics. However, recommendations are commonly made on the basis of only a restricted set of parameters. Without addressing uncertainty and variability in model parameters we risk ineffective management, resulting in wasted resources and an escalating problem if early chances to control spread are missed.
Using available data for Pinus nigra in ungrazed and grazed grassland and shrubland in New Zealand, we parameterized a stage‐structured spread model to calculate invasion wave speed, population growth rate and their sensitivities and elasticities to population parameters. Uncertainty distributions of parameters were used with the model to generate confidence intervals (CI) about the model predictions.
Ungrazed grassland environments were most vulnerable to invasion and the highest elasticities and sensitivities of invasion speed were to long‐distance dispersal parameters. However, there was overlap between the elasticity and sensitivity CI on juvenile survival, seedling establishment and long‐distance dispersal parameters, indicating overlap in their effects on invasion speed.
While elasticity of invasion speed to long‐distance dispersal was highest in shrubland environments, there was overlap with the CI of elasticity to juvenile survival. In shrubland invasion speed was most sensitive to the probability of establishment, especially when establishment was low. In the grazed environment elasticity and sensitivity of invasion speed to the severity of grazing were consistently highest. Management recommendations based on elasticities and sensitivities depend on the vulnerability of the habitat.
Synthesis and applications. Despite considerable uncertainty in demography and dispersal, robust management recommendations emerged from the model. Proportional or absolute reductions in long‐distance dispersal, juvenile survival and seedling establishment parameters have the potential to reduce wave speed substantially. Plantations of wind‐dispersed invasive conifers should not be sited on exposed sites vulnerable to long‐distance dispersal events, and trees in these sites should be removed. Invasion speed can also be reduced by removing seedlings, establishing competitive shrubs and grazing. Incorporating uncertainty into the modelling process increases our confidence in the wide applicability of the management strategies recommended here.
Identification of Dopamine, Gonadotrophin‐Releasing Hormone‐I, and Vasoactive Intestinal Peptide Neurones Activated by Electrical Stimulation to the Medial Preoptic Area of the Turkey Hypothalamus: A Potential Reproductive Neuroendocrine Circuit
Authors: Al‐Zailaie K. A. , Kang S. W. , Youngren O. M. , Thayananuphat A. , Bakken T. , Chaiseha Y. , Millam J. R. , Proudman J. A. , El Halawani M. E. 
Published: May 2006

AbstractThe neural and neurochemical substrates regulating reproduction in birds remain vaguely defined. The findings that electrical stimulation in the medial preoptic area (ES/MPOA) or intracerebroventricular infusion of dopamine (DA) stimulated luteinising hormone (LH) and prolactin (PRL) release in female turkeys, led to the suggestion that ES/MPOA might help to clarify the DA circuitry regulating LH and PRL. We used c‐fos mRNA and tyrosine hydroxylase immunoreactivity as measured by double in situ hybridisation/immunocytochemistry (ISH/ICC) to determine which group/subgroup of DA neurones was activated following unilateral ES/MPOA. To establish that the reproductive neuroendocrine system was activated, double ISH/ICC was also conducted on c‐fos/gonadotrophin‐releasing hormone‐I (GnRH‐I) and c‐fos/vasoactive intestinal peptide (VIP). Changes in circulating LH and PRL were determined by radioimmunoassay. Unilateral ES/MPOA (100 µA, right side) of anaesthetised laying turkeys for 30 min increased circulating LH and PRL levels. It also induced c‐fos mRNA expression on the ipsilateral side by all GnRH‐I neurones within the septopreoptic region, implying that GnRH‐I neurones in this region share similar circuitry. VIP neurones within the nucleus infundibularis were the only VIP group to show c‐fos mRNA expression, suggesting their involvement in ES/MPOA induced PRL release. c‐fos mRNA expression was also observed in a subgroup of DA neurones in the nucleus mamillaris lateralis (ML). To our knowledge, the present study is the first to show that activation of DAergic cells in the ML is associated with the activation of GnRH‐I and VIP neurones and the release of LH and PRL. It is likely that ES/MPOA activated VIP/GnRH‐I neurones via activation of DA neurones in the ML, as this was the only DA subgroup that showed c‐fos mRNA expression.
Portal fusion protein constraints on function in DNA packaging of bacteriophage T4
Authors: Baumann Richard G. , Mullaney Julienne , Black Lindsay W. 
Published: May 2006

SummaryArchitecturally conserved viral portal dodecamers are central to capsid assembly and DNA packaging. To examine bacteriophage T4 portal functions, we constructed, expressed and assembled portal gene 20 fusion proteins. C‐terminally fused (gp20–GFP, gp20–HOC) and N‐terminally fused (GFP–gp20 and HOC–gp20) portal fusion proteins assembled in vivo into active phage. Phage assembled C‐terminal fusion proteins were inaccessible to trypsin whereas assembled N‐terminal fusions were accessible to trypsin, consistent with locations inside and outside the capsid respectively. Both N‐ and C‐terminal fusions required coassembly into portals with ∼50% wild‐type (WT) or near WT‐sized 20am truncated portal proteins to yield active phage. Trypsin digestion of HOC–gp20 portal fusion phage showed comparable protection of the HOC and gp20 portions of the proteolysed HOC–gp20 fusion, suggesting both proteins occupy protected capsid positions, at both the portal and the proximal HOC capsid‐binding sites. The external portal location of the HOC portion of the HOC–gp20 fusion phage was confirmed by anti‐HOC immuno‐gold labelling studies that showed a gold ‘necklace’ around the phage capsid portal. Analysis of HOC–gp20‐containing proheads showed increased HOC protein protection from trypsin degradation only after prohead expansion, indicating incorporation of HOC–gp20 portal fusion protein to protective proximal HOC‐binding sites following this maturation. These proheads also showed no DNA packaging defect in vitro as compared with WT. Retention of function of phage and prohead portals with bulky internal (C‐terminal) and external (N‐terminal) fusion protein extensions, particularly of apparently capsid tethered portals, challenges the portal rotation requirement of some hypothetical DNA packaging mechanisms.
Virus DNA translocation: progress towards a first ascent of Mount Pretty Difficult
Authors: Maluf Nasib K. , Feiss Michael 
Published: May 2006

SummaryVirion DNA molecules of large dsDNA viruses are highly condensed. To pack the DNA, an ATP hydrolysis‐powered motor translocates the DNA into a preformed empty protein shell, the prohead. The icosahedral prohead has a special fivefold vertex, the portal vertex, where the translocation machinery acts. The portal vertex contains the portal protein, a gear‐shaped dodecamer of radially disposed subunits with a central channel for DNA entry. The symmetry mismatch between the fivefold symmetry of the shell vertex and the 12‐fold symmetry of the portal protein has prompted DNA packaging models in which ATP‐driven portal protein rotation drives DNA translocation. In this issue of Molecular Microbiology, Baumann and colleagues test portal rotation models using bacteriophage T4. A fusion between the gp20 portal protein and the HOC external shell decoration protein is used to create a block to portal rotation. Finding that DNA packaging is unimpeded in proheads containing the fusion argues that portal rotation is not crucial to DNA translocation. The paper is a landmark for describing direct testing of the mechanism of DNA translocation.
The glycosylphosphatidylinositol (GPI) biosynthetic pathway of bloodstream‐form Trypanosoma brucei is dependent on the de novo synthesis of inositol
Authors: Martin Kirstee L. , Smith Terry K. 
Published: May 2006

SummaryIn bloodstream‐form Trypanosoma brucei (the causative agent of African sleeping sickness) the glycosylphosphatidylinositol (GPI) anchor biosynthetic pathway has been validated genetically and chemically as a drug target. The conundrum that GPI anchors could not be in vivo labelled with [3H]‐inositol led us to hypothesize that de novo synthesis was responsible for supplying myo‐inositol for phosphatidylinositol (PI) destined for GPI synthesis. The rate‐limiting step of the de novo synthesis is the isomerization of glucose 6‐phosphate to 1‐d‐myo‐inositol‐3‐phosphate, catalysed by a 1‐d‐myo‐inositol‐3‐phosphate synthase (INO1). When grown under non‐permissive conditions, a conditional double knockout demonstrated that INO1 is an essential gene in bloodstream‐form T. brucei. It also showed that the de novo synthesized myo‐inositol is utilized to form PI, which is preferentially used in GPI biosynthesis. We also show for the first time that extracellular myo‐inositol can in fact be used in GPI formation although to a limited extent. Despite this, extracellular inositol cannot compensate for the deletion of INO1. Supporting these results, there was no change in PI levels in the conditional double knockout cells grown under non‐permissive conditions, showing that perturbation of growth is due to a specific lack of de novo synthesized myo‐inositol and not a general inositol‐less death. These results suggest that there is a distinction between de novo synthesized myo‐inositol and that from the extracellular environment.
Two different Pseudomonas aeruginosa chemosensory signal transduction complexes localize to cell poles and form and remould in stationary phase
Authors: Güvener Zehra Tüzün , Tifrea Delia F. , Harwood Caroline S. 
Published: May 2006

SummaryPseudomonas aeruginosa has sets of sensory genes designated che and che2. The che genes are required for flagella‐mediated chemotaxis. The che2 genes are expressed in the stationary phase of growth and are probably also involved in flagella–mediated behavioural responses. P. aeruginosa also has 26 chemoreceptor genes, six of which are preferentially expressed in stationary phase. Subcellular localization experiments indicated that Che proteins form signal transduction complexes at cell poles throughout growth. Cyan fluorescent protein (CFP)‐tagged McpA, a stationary phase‐expressed chemoreceptor, appeared and colocalized with yellow fluorescent protein (YFP)‐tagged CheA when cells entered stationary phase. This indicates that P. aeruginosa chemotaxis protein complexes are subject to remoulding by chemoreceptor proteins that are expressed when cells stop growing. CheA‐CFP and CheY2‐YFP tagged proteins that were coexpressed in the same cell had separate subcellular locations, indicating that Che2 proteins do not enter into direct physical interactions with Che proteins. Che2 protein complex formation required McpB, another stationary phase induced chemoreceptor that is predicted to be soluble. This implies that Che2 complexes have a function that depends on just one chemoreceptor. Our results suggest that motile P. aeruginosa cells have signal transduction systems that are adapted to allow non‐growing cells to sense and respond to their environment differently from actively growing cells.
ABC transporter‐mediated release of a haem chaperone allows cytochrome c biogenesis
Authors: Feissner Robert E. , Richard‐Fogal Cynthia L. , Frawley Elaine R. , Kranz Robert G. 
Published: May 2006

SummaryAlthough organisms from all kingdoms have either the system I or II cytochrome c biogenesis pathway, it has remained a mystery as to why these two distinct pathways have developed. We have previously shown evidence that the system I pathway has a higher affinity for haem than system II for cytochrome c biogenesis. Here, we show the mechanism by which the system I pathway can utilize haem at low levels. The mechanism involves an ATP‐binding cassette (ABC) transporter that is required for release of the periplasmic haem chaperone CcmE to the last step of cytochrome c assembly. This ABC transporter is composed of the ABC subunit CcmA, and two membrane proteins, CcmB and CcmC. In the absence of CcmA or CcmB, holo(haem)CcmE binds to CcmC in a stable dead‐end complex, indicating high affinity binding of haem to CcmC. Expression of CcmA and CcmB facilitates formation of the CcmA2B1C1 complex and ATP‐dependent release of holoCcmE. We propose that the CcmA2B1C1 complex represents a new subgroup within the ABC transporter superfamily that functions to release a chaperone.
Validity and reliability of the MEDYN questionnaire for evaluation of functioning in mental health clients receiving occupational therapy
Authors: Odes Hodayah , Noter Ester , Nir Maya Bar , Marcus Dina , Shamir Yosefa , Nir Nira 
Published: May 2006

Background:  A number of questionnaires are currently available for measuring functionality of mental health clients; however, they are complex, clumsy to use and impossible to compare to each other. There is a clear need for a simple and straightforward tool that uses quantitative measures. We formulated a questionnaire based on occupational, behavioural and cognitive theories to assess the functioning of psychiatric inpatients receiving occupational therapy. Methods:  Thirty‐one patients hospitalised in a closed and an open ward and receiving occupational therapy were monitored during 4 weeks. Clinicians completed the questionnaire for each patient on a weekly basis. Results:  Interrater reliability was found to be generally high with correlations among the raters in the closed ward being higher than among those in the open ward. Both cognitive and general/social functioning improved over time and the improvement was associated with type of illness and duration of treatment. Conclusions:  The MEDYN questionnaire is a valid and reliable objective tool for functional assessment of this subgroup of patients.
Concerns of Young Women Who are Positive for Brca1 and/or Brca2
Authors: Hamilton Rebekah 
Published: May 2006

The purpose of the study was to examine the experience of predictive genetic testing for hereditary breast and ovarian cancer (HBOC) and to compare experiences of younger women (≤ 35 years old) to the older study cohort (36–60 years old).Grounded theory was used to examine the phenomenon of adults choosing to have predictive genetic testing for HBOC. A sample of 19 women, ten ≤ 35 years old was recruited through community and internet support group announcements. Semi‐structured interviews were conducted in‐person, by telephone or E‐mail: according to participant preference.Young women’s experiences were different particularly around concerns about: (i) career plans, (ii) reproduction, and (iii) intimate relationships. Other concerns not specific to young women but also described included: (i) family relationships, (ii) fears of personal mortality, (iii) life and health insurance, and (iv) health information needs.A commonly voiced experience specific to the young adult age group was feeling ‘out‐of‐place’ in the oncology clinics and support groups which participants perceived as being focused on concerns of older women. Further study may clarify the extent and nature of informational, emotional, social and decision support needs that are unique to this young adult population.