bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein-Tyrosine Phosphatase 1B Is Required for HER2/Neu–Induced Breast Cancer
Authors: Bentires-Alj Mohamed , Neel Benjamin G. 
Published: March 2007

Abstract
The protein-tyrosine phosphatase 1B (PTP1B; PTPN1) is an important regulator of mammalian metabolism and also helps control signaling by growth factors, cytokines, and extracellular matrix. Gene knockout studies in mice established PTP1B as a key negative regulator of the insulin and leptin receptors. Experiments using PTP1B−/− fibroblast lines, dominant-negative mutants, or small interfering RNAs indicate that PTP1B contributes to dephosphorylation of the epidermal growth factor receptor and platelet-derived growth factor receptors as well. However, PTP1B also may have some positive (signal enhancing) roles downstream of some growth factor receptors and integrins. Previous studies indicated that PTP1B is overexpressed in a significant subset of breast and ovarian cancers, especially in those overexpressing HER2/Neu (HER2+ tumors). However, experiments using tissue culture cells yield conflicting results on the effects of PTP1B in HER2 signaling, leaving the consequences of PTP1B overexpression for breast carcinogenesis unclear. To determine how PTP1B deficiency affects HER2-evoked breast tumorigenesis, we generated mouse mammary tumor virus (MMTV)–NeuNT transgenic mice lacking one or both alleles of PTP1B. Although heterozygous loss of PTP1B has no effect on tumorigenesis, homozygous PTP1B deficiency dramatically delays or prevents the onset of MMTV-NeuNT–evoked breast tumors. The effects of PTP1B deficiency correlate with defective extracellular signal-regulated kinase activation in preneoplastic mammary glands from compound mutant mice. In contrast, PTP1B deficiency has no effect on MMTV-polyoma middle T tumorigenesis. Our data raise the possibility that PTP1B inhibitors may be chemopreventative for some forms of breast cancer. [Cancer Res 2007;67(6):2420–4]
Structural investigations of the ferredoxin and terminal oxygenase components of the biphenyl 2,3-dioxygenase from Sphingobium yanoikuyae B1
Authors: Ferraro Daniel J , Brown Eric N , Yu Chi-Li , Parales Rebecca E , Gibson David T , Ramaswamy S 
Published: March 2007

Abstract

Background
The initial step involved in oxidative hydroxylation of monoaromatic and polyaromatic compounds by the microorganism Sphingobium yanoikuyae strain B1 (B1), previously known as Sphingomonas yanoikuyae strain B1 and Beijerinckia sp. strain B1, is performed by a set of multiple terminal Rieske non-heme iron oxygenases. These enzymes share a single electron donor system consisting of a reductase and a ferredoxin (BPDO-FB1). One of the terminal Rieske oxygenases, biphenyl 2,3-dioxygenase (BPDO-OB1), is responsible for B1's ability to dihydroxylate large aromatic compounds, such as chrysene and benzo[a]pyrene.

Results
In this study, crystal structures of BPDO-OB1 in both native and biphenyl bound forms are described. Sequence and structural comparisons to other Rieske oxygenases show this enzyme to be most similar, with 43.5 % sequence identity, to naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4. While structurally similar to naphthalene 1,2-dioxygenase, the active site entrance is significantly larger than the entrance for naphthalene 1,2-dioxygenase. Differences in active site residues also allow the binding of large aromatic substrates. There are no major structural changes observed upon binding of the substrate. BPDO-FB1 has large sequence identity to other bacterial Rieske ferredoxins whose structures are known and demonstrates a high structural homology; however, differences in side chain composition and conformation around the Rieske cluster binding site are noted.

Conclusion
This is the first structure of a Rieske oxygenase that oxidizes substrates with five aromatic rings to be reported. This ability to catalyze the oxidation of larger substrates is a result of both a larger entrance to the active site as well as the ability of the active site to accommodate larger substrates. While the biphenyl ferredoxin is structurally similar to other Rieske ferredoxins, there are distinct changes in the amino acids near the iron-sulfur cluster. Because this ferredoxin is used by multiple oxygenases present in the B1 organism, this ferredoxin-oxygenase system provides the structural platform to dissect the balance between promiscuity and selectivity in protein-protein electron transport systems.
Drug treatment program patients' hepatitis C virus (HCV) education needs and their use of available HCV education services
Authors: Strauss Shiela M , Astone-Twerell Janetta , Munoz-Plaza Corrine E , Des Jarlais Don C , Gwadz Marya , Hagan Holly , Osborne Andrew , Rosenblum Andrew 
Published: March 2007

AbstractBackgroundIn spite of the disproportionate prevalence of hepatitis C virus (HCV) infection among drug users, many remain uninformed or misinformed about the virus. Drug treatment programs are important sites of opportunity for providing HCV education to their patients, and many programs do, in fact, offer this education in a variety of formats. Little is known, however, about the level of HCV knowledge among drug treatment program patients, and the extent to which they utilize their programs' HCV education services.MethodsUsing data collected from patients (N = 280) in 14 U.S. drug treatment programs, we compared patients who reported that they never injected drugs (NIDUs) with past or current drug injectors (IDUs) concerning their knowledge about HCV, whether they used HCV education opportunities at their programs, and the facilitators and barriers to doing so. All of the programs were participating in a research project that was developing, implementing, and evaluating a staff training to provide HCV support to patients.ResultsAlthough IDUs scored higher on an HCV knowledge assessment than NIDUs, there were many gaps in HCV knowledge among both groups of patients. To address these knowledge gaps, all of the programs offered at least one form of HCV education: all offered 1:1 sessions with staff, 12 of the programs offered HCV education in a group format, and 11 of the programs offered this education through pamphlets/books. Only 60% of all of the participating patients used any of their programs' HCV education services, but those who did avail themselves of these HCV education opportunities generally assessed them positively. In all, many patients were unaware that HCV education was offered at their programs through individual sessions with staff, group meetings, and books/pamphlets, (42%, 49%, and 46% of the patients, respectively), and 22% were unaware thatanyHCV education opportunities existed.ConclusionEfforts especially need to focus on ensuring that all drug treatment program patients are made aware of and encouraged to use HCV education services at their programs.
Intensive care unit acquired infection has no impact on long-term survival or quality of life: a prospective cohort study
Authors: Ylipalosaari Pekka , Ala-Kokko Tero I , Laurila Jouko , Ohtonen Pasi , Syrjälä Hannu 
Published: March 2007

Abstract
Introduction
The aim of this study was to evaluate the impact of intensive care unit (ICU)-acquired infection on long-term survival and quality of life.

Methods
Long-term survival was prospectively evaluated among hospital survivors who had stayed in a mixed, university-level ICU for longer than 48 hours during a 14-month study period during 2002 to 2003. Health-related quality of life was assessed using the five-dimensional EuroQol (EQ-5D) questionnaire in January 2005.

Results
Of the 272 hospital survivors, 83 (30.5%) died after discharge during the follow-up period. The median follow-up time after hospital discharge was 22 months. Among patients without infection on admission, long-term mortality did not differ between patients who developed and those who did not develop an ICU-acquired infection (21.7% versus 26.9%; P = 0.41). Also, among patients with infection on admission, there was no difference in long-term mortality between patients who developed a superimposed (35.1%) and those who did not develop a superimposed (27.6%) ICU-acquired infection (P = 0.40). The EQ-5D response rate was 75 %. The patients who developed an ICU-acquired infection had significantly more problems with self-care (50%) than did those without an ICU-acquired infection (32%; P = 0.004), whereas multivariate analysis did not show ICU-acquired infection to be a significant risk factor for diminished self-care (odds ratio = 1.71, 95% confidence interval = 0.65–4.54; P = 0.28). General health status did not differ between those with and those without an ICU-acquired infection, as measured using the EuroQol visual-analogue scale (mean ± standard deviation EuroQol visual-analogue scale value: 60.2 ± 21 in patients without ICU-acquired infection versus 60.6 ± 22 in those with ICU-acquired infection). The current general level of health compared with status before ICU admission did not differ between the groups either. Only 36% of those employed resumed their previous jobs.

Conclusion
ICU-acquired infection had no impact on long-term survival. The patients with ICU-acquired infection more frequently experienced problems with self-care than did those without ICU infection, but ICU-acquired infection was not a significant risk factor for diminished self-care in multivariate analysis.
Bias in Variance Components Due to Nonresponse in Twin Studies
Authors: Dominicus Annica , Palmgren Juni , Pedersen Nancy L. 
Published: March 2007

AbstractIncomplete data on trait values may bias estimates of genetic and environmental variance components obtained from twin analyses. If the nonresponse mechanism is ‘ignorable’ then methods such as full information maximum likelihood estimation will produce consistent variance component estimates. If, however, nonresponse is ‘nonignorable’, then the situation is more complicated. We demonstrate that a within-pair correlation of nonresponse, possibly different for monozygotic (MZ) and dizygotic (DZ) twins, may well be compatible with ‘ignorability’. By means of Monte Carlo simulation, we assess the potential bias in variance component estimates for different types of nonresponse mechanisms. The simulation results guide the interpretation of analyses of data on perceptual speed from the Swedish Adoption/Twin Study of Aging. The results suggest that the dramatic decrease in genetic influences on perceptual speed observed after 13 years of follow-up is not attributable solely to dropout from the study, and thus support the hypothesis that genetic influences on some cognitive abilities decrease with age in late life.
Heritability and Stability of Resting Blood Pressure in Australian Twins
Authors: Hottenga Jouke-Jan , Whitfield John B. , de Geus Eco J. C. , Boomsma Dorret I. , Martin Nicholas G. 
Published: March 2007

AbstractIn Australian twins participating in three different studies (1979–1996), the contribution of genetic and environmental influences to variation in resting systolic (SBP) and diastolic blood pressure (DBP) was studied. The sample consisted of 368 monozygotic and 335 dizygotic twin pairs with measurements for both individuals. Blood pressure measurements in two studies were available for 115 complete twin pairs, and 49 twin pairs had measurements in three studies. This allowed assessment of blood pressure tracking over an average period of 12 years in the age range of 23 to 45 years. Multivariate analyses showed significant heritability (h2) of blood pressure in all studies (SBP h2= 19%–56%, DBP h2= 37%–52%). In addition, the analyses showed that the blood pressure tracking was explained by the same set of genetic factors. These results replicate an earlier finding in Dutch twins that also showed stability of the contribution of genetic factors to blood pressure tracking.
Chorion Type, Birthweight Discordance and Tooth-Size Variability in Australian Monozygotic Twins
Authors: Race Jonathan P. , Townsend Grant C. , Hughes Toby E. 
Published: March 2007

AbstractChorion type is an important variable that can affect the prenatal environment of monozygotic (MZ) twin pairs, leading to differences in growth and development. In particular, vascular anastomoses between monochorionic (MC) MZ twin pairs can lead to an imbalance in nutrition between co-twins. One objective of this study was to determine whether maternal reports, hospital records or birthweight discordances found in MZ co-twins provide reliable indications of monochorionicity. The other objective was to test the hypotheses that in MZ twin pairs of known chorion type, MC twin pairs would show greater birthweight differences and greater within-pair variability in permanent tooth size than dichorionic (DC) twin pairs, reflecting greater differences in intrauterine environment between MC MZ pairs. Birthweights and tooth size data were recorded for 170 pairs of MZ Australian twins enrolled in an ongoing study of dentofacial growth and development. Chorion type based on maternal reports was compared with that based on hospital records for a subsample of 68 pairs of these MZ twins. Maternal reports were found to be unreliable for determining chorion type and hospital records often did not provide enough information to be certain about chorionicity. For 27 twin pairs with confirmed chorion type, associations were tested between birthweight discordances in MZ twin pairs and chorion type, and also between intrapair variances for tooth size and chorion type. A significant association was noted between birthweight discordance and chorion type (p<.05), with greater discordances occurring more often in MC twin pairs. Although significant heterogeneity of intrapair variances for tooth size was found in only 5 of 48 comparisons, intrapair variances for crown dimensions were greater significantly more often in MC pairs than DC pairs (p<.05). Our findings indicated that neither maternal reports nor often hospital records can be relied upon for information on chorion type. However, when analyses were performed on data for MZ twin pairs of known chorion type, we found evidence of a significant association between intrapair birthweight differences and chorion type and also between intrapair variances of dental crown measurements and chorion type. Consistent with our hypotheses, large birthweight discordances were found to occur more often in MC twin pairs than DC twin pairs, and intrapair variances for tooth size in MC twin pairs exceeded those in DC twin pairs more often than expected due to chance.
Breastfeeding Rates Among Singletons, Twins and Triplets in Japan: A Population-Based Study
Authors: Yokoyama Yoshie , Wada Saeko , Sugimoto Masako , Katayama Mari , Saito Miyuki , Sono Jun 
Published: March 2007

AbstractThis study was performed to determine the rates of breastfeeding among singletons, twins and triplets in Japan, and identify factors associated with the decision to breastfeed or bottle-feed. We analyzed a database of medical check-up of infants aged 3 to 6 months between April 2001 and July 2004 in Nishinomiya City in Japan. This medical check-up is given to almost 100% of infants in Japan and the data of 15,262 infants were analyzed. Among these, 14,963 (98.0%) were singletons, 290 (1.9%) were twins and 9 (0.1%) were triplets. Exclusive breast-feeding was chosen by 6680 (43.8%) mothers, mixed-feeding by 4645 (30.4%) mothers, and bottle-feeding with formula milk only by 3900 (25.6%) mothers. The rate of exclusive breastfeeding among twins or triplets was significantly lower than among singleton babies: 4.1% among twins or triplets, and 44.7% among singletons. Moreover, twins and triplets were independently associated with a higher rate of bottle-feeding: the odds ratio indicated that mothers who had twins or triplets were 2.44 times more likely to choose bottle-feeding with formula milk only than those who had singletons. Sucking ability at birth was associated with a higher rate of bottle-feeding: the odds ratio indicated that mothers who had infants with poor sucking ability at birth were 1.56 times more likely to choose bottle-feeding as those who had infants with normal sucking ability.
Identification of Twin Pairs From Large Population-Based Samples
Authors: Webbink Dinand , Roeleveld Jaap , Visscher Peter M. 
Published: March 2007

AbstractThe basis of most twin studies is the ascertainment of twins, often through twin registries, and determination of zygosity. The current rate of twin births in many industrialized countries implies that in the near future around 3% or more of individuals will be a twin. Hence, there are and will be a lot of twins around and many of those will not participate in twin studies. However, if large population-based samples are available that include appropriate identifiers, then twins can be detected and twin studies performed, even in the absence of zygosity information. We quantified the number of twin pairs that could be detected from a longitudinal survey in the Netherlands, which aims to answer questions about educational strategies and performance in primary education in the Netherlands. We detected 2865 twin pairs if we used a coded name identifier, date of birth, school, grade and year of survey, which is 2.01% of 284,945 pupils in five cohorts. Relaxing our selection criteria increased the number of apparent twin pairs identified, most of which are false positives due to chance matching of identification criteria. We show that the intraclass correlation on measured phenotypes can be used as a quality control measure for twin identification, and quantify the proportion of false negatives (true twin pairs not identified) due to missing data and data coding errors. We compared our estimated rate of twins in the sample to census data and estimate that with our most stringent selection criteria we detect more than 80% of all twin pairs in the sample. We conclude that the identification of twin pairs from large population-based samples is feasible, rapid and accurate if the appropriate identifiers are available, and that twin pairs from such sources are a valuable resource for studies to answer scientific question about twins versus nontwins and about genetic and environmental factors of twin resemblance.
Refractive Errors in Twin Studies
Authors: Dirani Mohamed , Chamberlain Matthew , Garoufalis Pam , Chen Christine , Guymer Robyn H. , Baird Paul N. 
Published: March 2007

AbstractIt is estimated that 1.6 billion people worldwide have myopia, a refractive error, and this number is expected to increase to approximately 2.5 billion by the year 2020. It is now well established that both the environment and genetics play a role in the development of myopia. However, the exact contribution of each of these components to myopia development has yet to be completely determined. Twin studies (classical twin model) are commonly used to determine the weighting of genetic and environmental components in disease. Over the last century, twin studies have investigated the heritability of refractive errors in different sample populations and have collectively supported a genetic basis to refractive errors. However, different sample populations and methods of data collection have produced a wide range of heritability estimates ranging from .5 to .9. This article will review those twin studies that have investigated refractive error, particularly myopia, as well as biometric measures linked to refractive error, to compare heritability estimates and methodology designs.
Fetal Death Registration in Multiple Births: Anomalies and Clinical Significance
Authors: Pharoah Peter O. D. 
Published: March 2007

AbstractTrends in the civil registration of fetal death in multiple gestations that has occurred before, but expelled from the womb after, 24 weeks' gestation are examined using England and Wales 1993–2004 registration obtained from the Office for National Statistics. Count was made of fetal death registrations in which fetus papyraceous, fetal death before 24 weeks' gestation or fetocide before 24 weeks' gestation was recorded. There were 3700 fetal death registrations among 217,595 twin, triplet and higher order multiple births in England and Wales between 1993 and 2004. In 354 (9.6%) of these fetal deaths, death was recorded as having occurred before 24 weeks' gestation. There has been a threefold increase in such fetal death registrations. It is a legal requirement of parents to register a fetal death. The definition of a fetal death that meets formal registration criteria is that the fetus is expelled from the womb after 24 weeks' gestation. However, if the fetal death occurs before 24 weeks, there is confusion, nationally and internationally, whether or not registration is legally required. Fetal death in a multiple gestation has serious clinical implications for a surviving co-conceptus and failure to inform parents of an early death in a multiple gestation may have important repercussions. Legal definition for the registration of fetal death requires international agreement and application.
Nonadditive Genetic Effects on Hostility in South Korean Adolescent and Young Adult Twins
Authors: Hur Yoon-Mi 
Published: March 2007

AbstractHostility has been shown to be a vulnerability marker for various health problems. The present study examined genetic and environmental contributions to individual differences in hostility in South Korean adolescent and young adult twins. Seven hundred and nineteen same- and opposite-sex twin pairs aged from 13 to 23 years completed a hostility scale. The scalar sex-limitation model was applied to the data. The best fitting model indicated that 34% of the total variation of hostility was attributable to genetic factors operating in a nonadditive manner. The remaining 66% of the variance was associated with nonshared environmental influences and measurement error. These findings were largely consistent with results from previous twin studies of personality based on Caucasian twins, rendering support for the pervasive influence of genetic non-additivity on human personality traits and the generalization of the heritability of personality across human populations.