bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Blood Pressure During Pregnancy and Poor Perinatal Outcomes: An Obstetric Paradox
Authors: Zhang Jun , Klebanoff Mark A. 
Published: July 2002

Abstract
Low blood pressure during pregnancy has been associated with poor perinatal outcomes. However, whether this association is causal or is due to confounding has never been carefully assessed. The authors used data from the Collaborative Perinatal Project, a large prospective cohort study in 12 hospitals in the United States from 1959 to 1966. A total of 28,095 subjects were included. At first glance, it appeared that the lower the baseline blood pressure during pregnancy, the higher the incidence of very premature birth (&lt;34 weeks) and severe small for gestational age (&lt;5th percentile) in a consistent dose-response pattern. However, women with low blood pressure were generally younger, shorter, lighter, leaner, poorer, and more often a minority, and they gained less weight. After the authors controlled for these factors, low blood pressure was not associated with preterm birth (adjusted relative risks ranging from 0.86 to 0.93, p &gt; 0.05) or small for gestational age (relative risks ranging from 0.45 to 2.0). Therefore, the association between low blood pressure during pregnancy and poor perinatal outcomes is largely due to confounding by other risk factors. Low blood pressure by itself does not increase risk of poor perinatal outcomes at a population level. However, this conclusion may not apply to individual patients who also have a compromised plasma volume expansion or pathologic homeostasis.
Frequency of Eating During Pregnancy and Its Effect on Preterm Delivery
Authors: Maria Siega-Riz Anna , Herrmann Tracy S. , Savitz David A. , Thorp John M. 
Published: July 2002

Abstract
Frequency of eating or meal patterns during pregnancy may be a component of maternal nutrition relevant to pregnancy outcome. To identify meal patterns of pregnant women and investigate the relation between these meal patterns and preterm delivery, the authors performed an analysis using data from the Pregnancy, Infection, and Nutrition Study (n = 2,065). Women recruited from August 1995 to December 1998 were categorized by meal patterns on the basis of their reported number of meals (breakfast, lunch, and dinner) and snacks consumed per day during the second trimester. An optimal pattern was defined according to the Institute of Medicine recommendation of three meals and two or more snacks per day. In this population, 72 percent of the women met this recommendation, and 235 delivered preterm. Women who consumed meals/snacks less frequently were slightly heavier prior to pregnancy, were older, and had a lower total energy intake. In addition, these women had a higher risk of delivering preterm (adjusted odds ratio = 1.30, 95 percent confidence interval: 0.96, 1.76). There was no meaningful difference in the risk by early versus late preterm delivery, but those who delivered after premature rupture of the membranes (adjusted odds ratio = 1.87, 95 percent confidence interval: 1.02, 3.43) had a higher risk than those who delivered after preterm labor (adjusted odds ratio = 1.11, 95 percent confidence interval: 0.64, 1.89). This study supports previous animal model work of an association between decreased frequency of eating and preterm delivery.
Methylenetetrahydrofolate Reductase 677 C/T Genotype and Cardiovascular Disease Mortality in Postmenopausal Women
Authors: Roest Mark , van der Schouw Yvonne T. , Grobbee Diederick E. , Tempelman Mariëlle J. , de Groot Philip G. , Sixma Jan J. , Banga Jan Dirk 
Published: July 2002

Abstract
Methylenetetrahydrofolate reductase (MTHFR) is involved in the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. A 677 C/T single nucleotide polymorphism localized in the MTHFR gene is associated with both thermolability and reduced activity of the enzyme and is associated with increased homocysteine levels. The authors investigated the relation between the MTHFR 677 C/T polymorphism and risk of cardiovascular disease mortality in a cohort study of 12,239 women initially aged 52–67 years with a maximum follow-up time of 18 years (1976–1995; 153,732 woman-years of follow-up). The cardiovascular disease mortality rate was highest among women with the MTHFR 677 CC wild-type genotype and lowest among MTHFR 677 TT homozygotes. In comparison with women with the 677 CC wild-type genotype, age-adjusted rate ratios were 0.7 (95% confidence interval: 0.5, 0.9) for 677 CT heterozygotes and 0.6 (95% confidence interval: 0.4, 1.0) for 677 TT homozygotes. The possibility that this relation is a chance finding must be considered, because the relation is weak and of borderline significance. However, it provides an important argument against the view that increased levels of homocysteine directly raise cardiovascular disease risk.
Dietary and Other Methyl-Group Availability Factors and Pancreatic Cancer Risk in a Cohort of Male Smokers
Authors: Stolzenberg-Solomon Rachael Z. , Pietinen Pirjo , Barrett Michael J. , Taylor Philip R. , Virtamo Jarmo , Albanes Demetrius 
Published: July 2002

Abstract
The authors examined prospectively whether dietary folate and other factors known to influence methyl-group availability were associated with the development of exocrine pancreatic cancer within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort. Of the 27,101 healthy male smokers aged 50–69 years who completed a self-administered dietary questionnaire at baseline, 157 developed pancreatic cancer during up to 13 years of follow-up from 1985 to 1997. Cox proportional hazards models were used to estimate the hazards ratios and 95% confidence intervals. The adjusted hazards ratio comparing the highest with the lowest quintile of dietary folate intake was 0.52 (95% confidence interval: 0.31, 0.87; p-trend = 0.05). Dietary methionine, alcohol intake, and smoking history did not modify this relation. No significant associations were observed between dietary methionine, vitamins B6 and B12, or alcohol intake and pancreatic cancer risk. Consistent with prior studies, this study shows that cigarette smoking was associated with an increased risk (highest compared with lowest quintile, cigarettes per day: hazards ratio = 1.82; 95% confidence interval: 1.10, 3.03; p-trend = 0.05). These results support the hypothesis that dietary folate intake is inversely associated with the risk of pancreatic cancer and confirm the risk associated with greater cigarette smoking.
Imagene: an integrated computer environment for sequence annotation and analysis.
Authors: M√©digue C , Rechenmann F , Danchin A , Viari A 
Published: July 2002

Abstract
MOTIVATION: To be fully and efficiently exploited, data coming from sequencing projects together with specific sequence analysis tools need to be integrated within reliable data management systems. Systems designed to manage genome data and analysis tend to give a greater importance either to the data storage or to the methodological aspect, but lack a complete integration of both components. RESULTS: This paper presents a co-operative computer environment (called Imagenetrade mark) dedicated to genomic sequence analysis and annotation. Imagene has been developed by using an object-based model. Thanks to this representation, the user can directly manipulate familiar data objects through icons or lists. Imagene also incorporates a solving engine in order to manage analysis tasks. A global task is solved by successive divisions into smaller sub-tasks. During program execution, these sub-tasks are graphically displayed to the user and may be further re-started at any point after task completion. In this sense, Imagene is more transparent to the user than a traditional menu-driven package. Imagene also provides a user interface to display, on the same screen, the results produced by several tasks, together with the capability to annotate these results easily. In its current form, Imagene has been designed particularly for use in microbial sequencing projects. AVAILABILITY: Imagene best runs on SGI (Irix 6.3 or higher) workstations. It is distributed free of charge on a CD-ROM, but requires some Ilog licensed software to run. Some modules also require separate license agreements. Please contact the authors for specific academic conditions and other Unix platforms. CONTACT: imagene home page: http://wwwabi.snv.jussieu.fr/imagene
Identification of novel multi-transmembrane proteins from
genomic databases using quasi-periodic structural properties
Authors: Kim Junhyong , Moriyama Etsuko N. , Warr Coral G. , Clyne Peter J. , Carlson John R. 
Published: July 2002

Abstract
Motivation: Identification of novel G protein-coupled receptors and other multi-transmembrane proteins from genomic databases using structural features.
Results: Here we describe a new algorithm for identifying multi-transmembrane proteins from genomic databases with a specific application to identifying G protein-coupled receptors (GPCRs) that we call quasi-periodic feature classifier (QFC). The QFC algorithm uses concise statistical variables as the ‘feature space’ to characterize the quasi-periodic physico-chemical properties of multi-transmembrane proteins. For the case of identifying GPCRs, the variables are then used in a non-parametric linear discriminant function to separate GPCRs from non-GPCRs. The algorithm runs in time linearly proportional to the number of sequences, and performance on a test dataset shows 96% positive identification of known GPCRs. The QFC algorithm also works well with short random segments of proteins and it positively identified GPCRs at a level greater than 90% even with segments as short as 100 amino acids. The primary advantage of the algorithm is that it does not directly use primary sequence patterns which may be subject to sampling bias. The utility of the new algorithm has been demonstrated by the isolation from the Drosophila genome project database of a novel class of seven-transmembrane proteins which were shown to be the elusive olfactory receptor genes of Drosophila.
Availability: C++/Perl available from http://jkim.eeb.yale.edu/index.html
Contact: Junhyong Kim, Dept. of Ecology and Evolutionary Biology, Yale University, P.O. Box 208106, New Haven, CT 06520-8106; junhyong.kim@yale.edu
Supplementary information: Test dataset and training dataset are available from http://jkim.eeb.yale.edu/index.html
**** To whom correspondence should be addressed.
BALL—rapid software prototyping in computational

molecular biology
Authors: Kohlbacher Oliver , Lenhof Hans-Peter 
Published: July 2002

Abstract
Motivation: Rapid software prototyping can significantly reduce development times in the field of computational molecular biology and molecular modeling. Biochemical Algorithms Library (BALL) is an application framework in C++that has been specifically designed for this purpose.
Results: BALL provides an extensive set of data structures as well as classes for molecular mechanics, advanced solvation methods, comparison and analysis of protein structures, file import/export, and visualization. BALL has been carefully designed to be robust, easy to use, and open to extensions. Especially its extensibility which results from an object-oriented and generic programming approach distinguishes it from other software packages. BALL is well suited to serve as a public repository for reliable data structures and algorithms. We show in an example that the implementation of complex methods is greatly simplified when using the data structures and functionality provided by BALL.
Availability: BALL is available via internet from http://www.mpi-sb.mpg.de/BALL/. It may be used free of charge for research and teaching. Commercial licenses are available upon request.
Contact: O.Kohlbacher, oliver@mpi-sb.mpg.de
To whom correspondence should be addressed.
Maintenance of a Smoking Cessation Program in Public Health Clinics beyond the Experimental Evaluation Period
Authors: Manfredi Clara , Crittenden Kathleen , Cho Young Ik , Engler Julie , Warnecke Richard 
Published: July 2002

Objectives. As phase 3 of a study to evaluate a smoking cessation program in public health practice, the authors assess the maintenance and impact of the It's Time smoking cessation program in seven public maternal and child health clinics in Chicago. Methods. The authors interviewed 404 clinic patients in the study's baseline phase (prior to introduction of the It's Time intervention program), and 610 in the program maintenance phase (in the year after experimental evaluation had ended) to assess exposure to smoking cessation interventions offered at the clinic, and smoking cessation outcomes (quit, actions toward quitting, scores on action, motivation, readiness, and confidence scales). The authors controlled for clustering of smokers within clinics, smokers' characteristics prior to clinic visit, and type of clinic service. They compared outcomes by study group (control or intervention) to which each clinic had been assigned in the earlier experimental phase. Results. Compared to baseline, smokers in the maintenance phase had greater exposure to posters, provider advice and booklet, and better outcomes on seven of eight smoking cessation measures, including quitting. These improvements were larger for clinics with prior experience implementing It's Time. Conclusion. Participation in the experimental evaluation of the It's Time program prepared and possibly motivated the clinics to continue the program. Continuing the program resulted in greater delivery of interventions and improved smoking cessation outcomes for smokers in the clinics.
Pregnancy Feelings among Adolescents Awaiting Pregnancy Test Results
Authors: Hellerstedt Wendy L. , Fee Rebecca M. , McNeely Clea A. , Sieving Renee E. , Shew Marcia L. , Resnick Michael D. 
Published: July 2002

Objective. The authors surveyed adolescent girls about their feelings regarding pregnancy. Methods. A survey was administered to 117 13- to 18-year-olds who obtained pregnancy tests at nine clinics in Minneapolis and St. Paul, Minnesota, in 1998. The survey included four measures of pregnancy feelings. The authors used bivariate and multivariate logistic regression analyses to examine the associations of these measures with engagement with school, future expectations, social and environmental characteristics, and perceived partner desire for pregnancy. Results. The four measures of pregnancy feelings were highly correlated ( P = 0.0001). Participants reported a range of positive, negative, and ambivalent feelings on all measures. Perceived partner desire for pregnancy, limited future expectations, and lack of school engagement were significantly associated with positive pregnancy feelings for the four measures. Conclusions. Successful adolescent pregnancy prevention interventions may include the involvement of partners and key adults as well as strategies to enhance the educational or employment aspirations of girls and adolescents.
A Computerized Tool for Evaluating the Effectiveness of Preventive Interventions
Authors: Daumit Gail , Boulware L.E. , Powe N.R. , Minkovitz C.S. , Frick K.D. , Anderson L.A. , Janes G.R. , Lawrence R.S. 
Published: July 2002

In identifying appropriate strategies for effective use of preventive services for particular settings or populations, public health practitioners employ a systematic approach to evaluating the literature. Behavioral intervention studies that focus on prevention, however, pose special challenges for these traditional methods. Tools for synthesizing evidence on preventive interventions can improve public health practice. The authors developed a literature abstraction tool and a classification for preventive interventions. They incorporated the tool into a PC-based relational database and user-friendly evidence reporting system, then tested the system by reviewing behavioral interventions for hypertension management. They performed a structured literature search and reviewed 100 studies on behavioral interventions for hypertension management. They abstracted information using the abstraction tool and classified important elements of interventions for comparison across studies. The authors found that many studies in their pilot project did not report sufficient information to allow for complete evaluation, comparison across studies, or replication of the intervention. They propose that studies reporting on preventive interventions should ( a) categorize interventions into discrete components; ( b) report sufficient participant information; and ( c) report characteristics such as intervention leaders, timing, and setting so that public health professionals can compare and select the most appropriate interventions.
The labile brain. I. Neuronal transients and nonlinear coupling
Authors: Friston Karl J. 
Published: July 2002

In this, the first of three papers, the nature of, and motivation for, neuronal transients is described in relation to characterizing brain dynamics. This paper deals with some basic aspects of neuronal dynamics, interactions, coupling and implicit neuronal codes. The second paper develops neuronal transients and nonlinear coupling in the context of dynamic instability and complexity, and suggests that instability or lability is necessary for adaptive self–organization. The final paper addresses the role of neuronal transients through information theory and the emergence of spatio–temporal receptive fields and functional specialization.
By considering the brain as an ensemble of connected dynamic systems one can show that a sufficient description of neuronal dynamics comprises neuronal activity at a particular time and its recent history. This history constitutes a neuronal transient. As such, transients represent a fundamental metric of neuronal interactions and, implicitly, a code employed in the functional integration of brain systems. The nature of transients, expressed conjointly in distinct neuronal populations, reflects the underlying coupling among populations. This coupling may be synchronous (and possibly oscillatory) or asynchronous. A critical distinction between synchronous and asynchronous coupling is that the former is essentially linear and the latter is nonlinear. The nonlinear nature of asynchronous coupling enables the rich, context–sensitive interactions that characterize real brain dynamics, suggesting that it plays a role in functional integration that may be as important as synchronous interactions. The distinction between linear and nonlinear coupling has fundamental implications for the analysis and characterization of neuronal interactions, most of which are predicated on linear (synchronous) coupling (e.g. crosscorrelograms and coherence). Using neuromagnetic data it is shown that nonlinear (asynchronous) coupling is, in fact, more abundant and can be more significant than synchronous coupling.
On the involvement of electron transfer reactions in the fluorescence decay kinetics heterogeneity of proteins
Authors: Ababou Abdessamad , Bombarda Elisa 
Published: July 2002

AbstractTime‐resolved fluorescence study of single tryptophan‐containing proteins, nuclease, ribonuclease T1, protein G, glucagon, and mastoparan, has been carried out. Three different methods were used for the analysis of fluorescence decays: the iterative reconvolution method, as reviewed and developed in our laboratory, the maximum entropy method, and the recent method that we called “energy transfer” method. All the proteins show heterogeneous fluorescence kinetics (multiexponential decay). The origin of this heterogeneity is interpreted in terms of current theories of electron transfer process, which treat the electron transfer process as a radiationless transition. The theoretical electron transfer rate was calculated assuming the peptide bond carbonyl as the acceptor site. The good agreement between experimental and theoretical electron‐transfer rates leads us to suggest that the electron‐transfer process is the principal quenching mechanism of Trp fluorescence in proteins, resulting in heterogeneous fluorescence kinetics. Furthermore, the origin of apparent homogeneous fluorescence kinetics (monoexponential decay) in some proteins also can be explained on the basis of electron‐transfer mechanism.
Crystal structure of the transcription factor sc‐mtTFB offers insights into mitochondrial transcription
Authors: Schubot Florian D. , Chen Chun‐Jung , Rose John P. , Dailey Tamara A. , Dailey Harry A. , Wang Bi‐Cheng 
Published: July 2002

AbstractAlthough it is commonly accepted that binding of mitochondrial transcription factor sc‐mtTFB to the mitochondrial RNA polymerase is required for specific transcription initiation in Saccharomyces cerevisiae, its precise role has remained undefined. In the present work, the crystal structure of sc‐mtTFB has been determined to 2.6 Å resolution. The protein consists of two domains, an N‐terminal α/β‐domain and a smaller domain made up of four α‐helices. Contrary to previous predictions, sc‐mtTFB does not resemble Escherichia coli σ‐factors but rather is structurally homologous to rRNA methyltransferase ErmC'. This suggests that sc‐mtTFB functions as an RNA‐binding protein, an observation standing in contradiction to the existing model, which proposed a direct interaction of sc‐mtTFB with the mitochondrial DNA promoter. Based on the structure, we propose that the promoter specificity region is located on the mitochondrial RNA polymerase and that binding of sc‐mtTFB indirectly mediates interaction of the core enzyme with the promoter site.
Persistently conserved positions in structurally similar, sequence dissimilar proteins: Roles in preserving protein fold and function
Authors: Friedberg Iddo , Margalit Hanah 
Published: July 2002

AbstractMany protein pairs that share the same fold do not have any detectable sequence similarity, providing a valuable source of information for studying sequence‐structure relationship. In this study, we use a stringent data set of structurally similar, sequence‐dissimilar protein pairs to characterize residues that may play a role in the determination of protein structure and/or function. For each protein in the database, we identify amino‐acid positions that show residue conservation within both close and distant family members. These positions are termed “persistently conserved”. We then proceed to determine the “mutually” persistently conserved (MPC) positions: those structurally aligned positions in a protein pair that are persistently conserved in both pair mates. Because of their intra‐ and interfamily conservation, these positions are good candidates for determining protein fold and function. We find that 45% of the persistently conserved positions are mutually conserved. A significant fraction of them are located in critical positions for secondary structure determination, they are mostly buried, and many of them form spatial clusters within their protein structures. A substitution matrix based on the subset of MPC positions shows two distinct characteristics: (i) it is different from other available matrices, even those that are derived from structural alignments; (ii) its relative entropy is high, emphasizing the special residue restrictions imposed on these positions. Such a substitution matrix should be valuable for protein design experiments.