bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parental age at delivery, birth order, birth weight and gestational age are associated with the risk of childhood Type 1 diabetes: a UK regional retrospective cohort study
Authors: Cardwell C. R. , Carson D. J. , Patterson C. C. 
Published: January 2005

AbstractAims  To investigate perinatal risk factors for childhood Type 1 diabetes in a UK population cohort.Methods  Perinatal data have been routinely recorded in Northern Ireland for all births in the period 1971–86 (n = 447 663). Diabetes status at the age of 15 years was ascertained in this cohort by identifying 991 children from 1079 registered with Type 1 diabetes diagnosed from 1971 to 2001 and date of birth in the period 1971–86.Results  Increased Type 1 diabetes risk was associated with higher maternal age, paternal age, birth weight and birth weight for gestational and lower gestational age. After adjustment for maternal age, the association between Type 1 diabetes and paternal age remained significant [relative risk (RR) = 1.52 (1.10, 2.09) comparing father's age 35 years or more to less than 25 years] but not vice versa [RR = 1.11 (0.80, 1.54) comparing mother's age 35 years or more to less than 25 years]. Increased birth order was associated with a significant decrease in the risk of Type 1 diabetes [adjusted RR = 0.75 (0.62, 0.90) comparing birth order three or more with firstborn], but this only became apparent when adjustment was made for maternal age. Furthermore this association with birth order was significant only for diabetes diagnosed under the age of 5 years.Conclusions  Our analysis demonstrates, for the first time in a UK regional cohort setting, that maternal age and paternal age at delivery, birth order, birth weight and gestational age are significantly associated with Type 1 diabetes risk.
Simple Heterogeneity Variance Estimation for Meta-Analysis
Authors: Sidik Kurex , Jonkman Jeffrey N. 
Published: January 2005

SummaryA simple method of estimating the heterogeneity variance in a random-effects model for meta-analysis is proposed. The estimator that is presented is simple and easy to calculate and has improved bias compared with the most common estimator used in random-effects meta-analysis, particularly when the heterogeneity variance is moderate to large. In addition, it always yields a non-negative estimate of the heterogeneity variance, unlike some existing estimators. We find that random-effects inference about the overall effect based on this heterogeneity variance estimator is more reliable than inference using the common estimator, in terms of coverage probability for an interval estimate.
Bivariate Modelling of Longitudinal Measurements of Two Human Immunodeficiency Type 1 Disease Progression Markers in the Presence of Informative Drop-Outs
Authors: Pantazis N. , Touloumi G. , Walker A. S. , Babiker A. G. 
Published: January 2005

SummaryThe main statistical problem in many epidemiological studies which involve repeated measurements of surrogate markers is the frequent occurrence of missing data. Standard likelihood-based approaches like the linear random-effects model fail to give unbiased estimates when data are non-ignorably missing. In human immunodeficiency virus (HIV) type 1 infection, two markers which have been widely used to track progression of the disease are CD4 cell counts and HIV–ribonucleic acid (RNA) viral load levels. Repeated measurements of these markers tend to be informatively censored, which is a special case of non-ignorable missingness. In such cases, we need to apply methods that jointly model the observed data and the missingness process. Despite their high correlation, longitudinal data of these markers have been analysed independently by using mainly random-effects models. Touloumi and co-workers have proposed a model termed the joint multivariate random-effects model which combines a linear random-effects model for the underlying pattern of the marker with a log-normal survival model for the drop-out process. We extend the joint multivariate random-effects model to model simultaneously the CD4 cell and viral load data while adjusting for informative drop-outs due to disease progression or death. Estimates of all the model’s parameters are obtained by using the restricted iterative generalized least squares method or a modified version of it using the EM algorithm as a nested algorithm in the case of censored survival data taking also into account non-linearity in the HIV–RNA trend. The method proposed is evaluated and compared with simpler approaches in a simulation study. Finally the method is applied to a subset of the data from the ‘Concerted action on seroconversion to AIDS and death in Europe’ study.
Live or let live: life‐history decisions of the breeding female Monteiro's Hornbill Tockus monteiri
Authors: MILLS MICHAEL S. L. , BOIX‐HINZEN CHRISTIAN , PLESSIS MORNÉ A. DU 
Published: January 2005

Life‐history theory maintains that long‐lived species such as hornbills (Bucerotiformes) maximize lifetime fecundity by ensuring adult survival, rather than investing in current reproductive output. Unusually, female Tockus hornbills are sealed into the nest cavity during breeding, placing a large burden on the male who feeds her and the nestlings for up to 9 weeks. Early departure to help feed young may improve nestling survival, but could reduce female survival if moult is incomplete. We investigated whether departure time of the female Monteiro's Hornbill Tockus monteiri is more strongly related to measures of female fitness or juvenile condition. Departure was independent of nestling development and growth, instead depending on female state. At departure, variability in condition between females was smaller than at any other stage, implying a strong stabilizing selection on optimal female departure condition. Similarly, moult showed signs of being completed, and variability in the state of moult between females was lowest at departure. Both predictions were met in favour of the hypothesis that Monteiro's Hornbills would base the timing of their departure from the nest on maximizing their own survival. Thus, as predicted, future reproductive potential takes precedence over current reproductive output in a trade‐off decision in this species.
Distribution, density, diet and productivity of the Scops Owl Otus scops in the Italian Alps
Authors: MARCHESI LUIGI , SERGIO FABRIZIO 
Published: January 2005

The Scops Owl Otus scops is probably the least known European owl. We surveyed Scops Owls in the Trento region (6200 km2) of the central–eastern Italian Alps between 1995 and 2003 and we intensively monitored a subpopulation in a 50‐km2 plot between 2000 and 2003. In the whole region, we found 81 territories concentrated in 21, low‐elevation 100‐km2 quadrats. Most territories were associated with villages surrounded by extensively managed grassland (79%), arid areas with rocky outcrops and xerophytic vegetation (12%) and/or large urban areas and parks (6%). In the 50‐km2 plot, density varied between 52 and 64 territories/100 km2 annually. Territories were either solitary or clumped in loose colonies of 2–7 pairs. In contrast to previous studies, most nests used for laying were in holes and cracks of buildings (95%, n = 20). This may have been favoured by thermal and foraging advantages, but also involved some costs, such as predation by domestic cats and collision with cars. Median laying date was 29 May (n = 16) and the mean number of fledged young was 1.37 (n = 30), 1.95 (n = 21) and 2.00 (n = 20) per territorial, breeding and successful pair, respectively. The diet was dominated by grasshoppers of the family Tettigoniidae. Compared to previous studies, this population showed medium to high density and low productivity. The species seems to be dependent on traditional, extensive agro‐pastoralism and the main conservation threats include habitat loss through land abandonment and consequent forest expansion, which are probably best halted through subsidy schemes. From our results and published data, we estimate the population of the Scops Owl in the Italian Alps at 230–500 territories. There is an urgent need for further data on this largely overlooked species, especially from its Mediterranean strongholds.
Blood collection and transfusion in the United States in 1999
Authors: Sullivan Marian T. , Wallace Edward L. 
Published: January 2005

BACKGROUND:  Collection, processing, and transfusion of blood and blood components in the US in 1999 were measured and compared with prior years.STUDY DESIGN AND METHODS:  Questionnaires were completed by 2040 blood centers and hospitals. Statistical procedures were used to verify the representativeness of the sample and to estimate national totals.RESULTS:  The total US blood supply in 1999 was 13,876,000 units (before testing), 10.1 percent greater than in 1997. It included 13,109,000 allogeneic units, 651,000 autologous units, and 116,000 red cell (RBC) units collected by apheresis. Transfusion of whole blood and RBCs increased by 7.6 percent to 12,389,000 units. Platelet (PLT) transfusions totaled 9,052,000 PLT concentrate equivalent units, of which 66.5 percent were PLTs from apheresis. In comparison with 1997, the total number of PLT units transfused was unchanged, whereas single‐donor PLT units transfused increased by 6.7 percent and the transfusion of PLTs from whole blood (PLT concentrates) declined by 10.6 percent (a difference of approximately 400,000 units in each case).CONCLUSIONS:  The margin between transfusion demand and the total allogeneic supply in 1999 was 1,203,000 units, 9.1 percent of the supply. By comparison, the margin in 1997 was 7.2 percent, whereas in 1989 it was 13.8 percent. Similarly, the rate of blood collection in 1999 per 1000 population was 11.9 percent higher than the 1997 rate. During the same period, however, the rate of transfusion per 1000 population increased by 5.8 percent. Risk in the future lies primarily in the increasing demand for RBCs and further shrinkage of the supply‐and‐demand margin.
Understanding Canadian student motivations and beliefs about giving blood
Authors: Hupfer M.E. , Taylor D.W. , Letwin J.A. 
Published: January 2005

BACKGROUND:  A better understanding of Canadian blood donor beliefs and motivations is needed to develop targeted interventions. Recruiters must know how motivation variables and correlation patterns differ with donor experience and sex.STUDY DESIGN AND METHODS:  Data addressing reasons for donating, statements about the blood supply, beliefs about donation consequences, and reasons for avoiding donation were collected from 450 undergraduates. Principal components analysis was used to investigate the underlying factorial structure of each domain. Men‐women and donor‐nondonor differences were explored with multivariate analysis of variance techniques.RESULTS:  A bivariate model better represented donor beliefs than did a bipolar conceptualization. Negative beliefs distinguished donors and nondonors more so than did positive factors. Altruism dominated reasons for donating, whereas logistic factors accounted for the most variance in donation avoidance. Women were more concerned about adverse physical consequences, and nondonors expressed higher levels of groundless donation‐related fears.CONCLUSION:  Recruiters should consider the sex and donation experience of targets when they develop recruitment and retention strategies. Education programs aimed at overcoming fears and heightening awareness of need are recommended, as are operational improvements aimed at reducing barriers posed by time and inconvenience.
Isolation and Characterization of an Aldehyde Dehydrogenase Encoded by thealdBGene ofEscherichia coli
Authors: Ho Kwok Ki , Weiner Henry 
Published: January 2005

ABSTRACTAn aldehyde dehydrogenase was detected in crude cell extracts ofEscherichia coliDH5α. Growth studies indicated that the aldehyde dehydrogenase activity was growth phase dependent and increased in cells grown with ethanol. The N-terminal amino acid sequence of the purified enzyme identified the latter as an aldehyde dehydrogenase encoded byaldB, which was thought to play a role in the removal of aldehydes and alcohols in cells that were under stress. The purified enzyme showed an estimated molecular mass of 220 ± 8 kDa, consisting of four identical subunits, and preferred to use NADP and acetaldehyde. MgCl2increased the activity of the NADP-dependent enzyme with various substrates. A comparison of the effect of Mg2+ions on the bacterial enzyme with the effect of Mg2+ions on human liver mitochondrial aldehyde dehydrogenase revealed that the bacterial enzyme shared kinetic properties with the mammalian enzyme. An R197E mutant of the bacterial enzyme appeared to retain very little NADP-dependent activity on acetaldehyde.
Sulfur and Nitrogen Limitation inEscherichia coliK-12: Specific Homeostatic Responses
Authors: Gyaneshwar Prasad , Paliy Oleg , McAuliffe Jon , Popham David L. , Jordan Michael I. , Kustu Sydney 
Published: January 2005

ABSTRACTWe determined global transcriptional responses ofEscherichia coliK-12 to sulfur (S)- or nitrogen (N)-limited growth in adapted batch cultures and cultures subjected to nutrient shifts. Using two limitations helped to distinguish between nutrient-specific changes in mRNA levels and common changes related to the growth rate. Both homeostatic and slow growth responses were amplified upon shifts. This made detection of these responses more reliable and increased the number of genes that were differentially expressed. We analyzed microarray data in several ways: by determining expression changes after use of a statistical normalization algorithm, by hierarchical and k-means clustering, and by visual inspection of aligned genome images. Using these tools, we confirmed known homeostatic responses to global S limitation, which are controlled by the activators CysB and Cbl, and found that S limitation propagated into methionine metabolism, synthesis of FeS clusters, and oxidative stress. In addition, we identified several open reading frames likely to respond specifically to S availability. As predicted from the fact that theddpoperon is activated by NtrC, synthesis of cross-links between diaminopimelate residues in the murein layer was increased under N-limiting conditions, as was the proportion of tripeptides. Both of these effects may allow increased scavenging of N from the dipeptided-alanine-d-alanine, the substrate of the Ddp system.
Site-Directed Mutagenesis Analysis of Amino Acids Critical for Activity of the Type I Signal Peptidase of the Archaeon
Methanococcus voltae
Authors: Bardy Sonia L. , Ng Sandy Y. M. , Carnegie David S. , Jarrell Ken F. 
Published: January 2005

ABSTRACT

Site-directed mutagenesis studies of the signal peptidase of the methanogenic archaeon
Methanococcus voltae
identified three conserved residues (Ser
52
, His
122
, and Asp
148
) critical for activity. The requirement for one conserved aspartic acid residue distinguishes the archaeal enzyme from both the
Escherichia coli
and yeast Sec11 enzymes.
Characterization of the RokA and HexA Broad-Substrate-Specificity Hexokinases from
Bacteroides fragilis
and Their Role in Hexose and
N
-Acetylglucosamine Utilization
Authors: Brigham Christopher J. , Malamy Michael H. 
Published: January 2005

ABSTRACT

Bacteroides fragilis
, a human gastrointestinal commensal and an opportunistic pathogen, utilizes simple and complex sugars and polysaccharides for growth in the large intestine and at sites of infection. Because
B. fragilis
lacks transport-linked sugar phosphorylation systems, cytoplasmic kinase(s) was expected to be required for the phosphorylation of hexoses and hexosamines. We have now identified two hexose kinases that are important for growth of
B. fragilis
on glucose, mannose, and other sugars. One kinase (RokA), a member of the ROK family of proteins, was found to be the sole kinase for activation of
N
-acetyl-
d
-glucosamine (NAG). The other kinase (HexA) is responsible for the majority of the glucose kinase activity in the cell, although a
hexA
deletion mutant strain was not defective for growth on any substrate tested. Deletion of both the
rokA
and
hexA
kinase genes resulted in inability of the cell to use glucose, mannose, NAG, and many other sugars. We purified RokA and determined its approximate molecular mass to be 36.5 kDa. The purified RokA protein was shown to phosphorylate several substrates, including glucose, NAG, and mannose, but not
N
-acetylmannosamine or
N
-acetylneuraminic acid. Phylogenetic analysis of RokA showed that it is most similar to kinases from the
Cytophaga-Flavibacterium-Bacteroides
group, while HexA was most similar to other bacterial hexokinases and eukaryotic hexokinases.
Growth Kinetics of Extremely Halophilic
Archaea
(Family
Halobacteriaceae
) as Revealed by Arrhenius Plots
Authors: Robinson Jessie L. , Pyzyna Brandy , Atrasz Rachelle G. , Henderson Christine A. , Morrill Kira L. , Burd Anna Mae , DeSoucy Erik , Fogleman Rex E. , Naylor John B. , Steele Sarah M. , Elliott Dawn R. , Leyva Kathryn J. , Shand Richard F. 
Published: January 2005

ABSTRACT

Members of the family
Halobacteriaceae
in the domain
Archaea
are obligate extreme halophiles. They occupy a variety of hypersaline environments, and their cellular biochemistry functions in a nearly saturated salty milieu. Despite extensive study, a detailed analysis of their growth kinetics is missing. To remedy this, Arrhenius plots for 14 type species of the family were generated. These organisms had maximum growth temperatures ranging from 49 to 58°C. Nine of the organisms exhibited a single temperature optimum, while five grew optimally at more than one temperature. Generation times at these optimal temperatures ranged from 1.5 h (
Haloterrigena turkmenica
) to 3.0 h (
Haloarcula vallismortis
and
Halorubrum saccharovorum
). All shared an inflection point at 31 ± 4°C, and the temperature characteristics for 12 of the 14 type species were nearly parallel. The other two species (
Natronomonas pharaonis
and
Natronorubrum bangense
) had significantly different temperature characteristics, suggesting that the physiology of these strains is different. In addition, these data show that the type species for the family
Halobacteriaceae
share similar growth kinetics and are capable of much faster growth at higher temperatures than those previously reported.
Role of Integration Host Factor in the Transcriptional Activation of Flagellar Gene Expression in
Caulobacter crescentus
Authors: Muir Rachel E. , Gober James W. 
Published: January 2005

ABSTRACT

In the
Caulobacter crescentus
predivisional cell, class III and IV flagellar genes, encoding the extracytoplasmic components of the flagellum, are transcribed in the nascent swarmer compartment. This asymmetric expression pattern is attributable to the compartmentalized activity of the σ
54
-dependent transcriptional activator FlbD. Additionally, these temporally transcribed flagellar promoters possess a consensus sequence for the DNA-binding protein integration host factor (IHF), located between the upstream FlbD binding site and the promoter sequences. Here, we deleted the
C. crescentus
gene encoding the β-subunit of the IHF,
ihfB
(
himD
), and examined the effect on flagellar gene expression. The Δ
ihfB
strain exhibited a mild defect in cell morphology and impaired motility. Using flagellar promoter reporter fusions, we observed that expression levels of a subset of class III flagellar promoters were decreased by the loss of IHF. However, one of these promoters,
fliK-lacZ
, exhibited a wild-type cell cycle-regulated pattern of expression in the absence of IHF. Thus, IHF is required for maximal transcription of several late flagellar genes. The Δ
ihfB
strain was found to express significantly reduced amounts of the class IV flagellin, FljL, as a consequence of reduced transcriptional activity. Our results indicate that the motility defect exhibited by the Δ
ihfB
strain is most likely attributable to its failure to accumulate the class IV-encoded 27-kDa flagellin subunit, FljL.
Comparison of the Effect of Pentoxifylline and Captopril on Proteinuria in Patients with Type 2 Diabetes mellitus
Authors: Aminorroaya Ashraf , Janghorbani Mohsen , Rezvanian Hassan , Aminian Taghi , Gharavi Manouchehr , Amini Massoud 
Published: January 2005

<i>Objectives:</i> To compare the relative efficacy of pentoxifylline (PTX) and angiotensin-converting enzyme (ACE) inhibitor, captopril in the treatment of proteinuria of type 2 diabetic patients. <i>Design:</i> A randomized open, crossover, clinical trial conducted from October 2000 to March 2001. <i>Setting and Participants:</i> 39 patients with type 2 diabetes age 34–75 years were randomly allocated to the two treatment groups. The first group received PTX (400 mg three times a day) orally for a total of 2 months. The second group received captopril (25 mg three times a day) for 2 months. Response to treatment was assessed at 1, 2, 4, and 8 weeks after start of therapy. <i>Results:</i> Captopril appeared to be equivalent in efficacy and safety to PTX. A significant decrease in proteinuria occurred in both groups. Of the 20 patients treated with PTX, the mean (SD) of 24 h urinary protein decreased from 1.4 (0.7) to 1.0 (0.7) g/24 h (p < 0.05). Correspondingly, in the 19 patients treated with captopril, the mean (SD) of 24 h urinary protein decreased from 1.3 (0.7) to 0.8 (0.7) g/24 h (p < 0. 01). <i>Conclusion:</i> This study demonstrates that treatment with PTX and captopril both significantly reduce overt proteinuria in patients with type 2 diabetes. This effect of ACE inhibition has previously been shown to slow progression to renal failure and we postulate that treatment with PTX may have a similar benefit.
Regulator of G-protein signaling-5 induction in pericytes coincides with active vessel remodeling during neovascularization
Authors: Berger Mario , Bergers Gabriele , Arnold Bernd , Hämmerling Günter J. , Ganss Ruth 
Published: January 2005

AbstractWe identified regulator of G-protein signaling-5 (RGS-5) as an angiogenic pericyte marker at sites of physiologic and pathologic angiogenesis. In a mouse model of pancreatic islet cell carcinogenesis, RGS-5 is specifically induced in the vasculature of premalignant lesions during the “angiogenic switch” and further elevated in tumor vessels. Similarly, RGS-5 is overexpressed in highly angiogenic astrocytomas but not in hypoxia-inducible factor-1α (HIF-1α)–deficient tumors, which grow along preexisting brain capillaries without inducing neovessels. Elevated levels of RGS-5 in pericytes are also observed during wound healing and ovulation indicating a strong correlation between RGS-5 expression and active vessel remodeling beyond tumor angiogenesis. Moreover, antitumor therapy, which reverses tumor vasculature to an almost normal morphology, results in down-regulation of RGS-5 transcription. Taken together, these data demonstrate for the first time a factor that is specific for “activated” pericytes. This further supports the notion that pericytes, like endothelial cells, undergo molecular changes during neovascularization that makes them a novel target for antiangiogenic therapy.