Nuclear physics. Momentum sharing in imbalanced Fermi systems.

The atomic nucleus is composed of two different kinds of fermions: protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority of fermions (usually neutrons) to have a higher average momentum. Our high-energy electron-scattering measurements using (12)C, (27)Al, (56)Fe, and (208)Pb targets show that even in heavy, neutron-rich nuclei, short-range interactions between the fermions form correlated high-momentum neutron-proton pairs. Thus, in neutron-rich nuclei, protons have a greater probability than neutrons to have momentum greater than the Fermi momentum. This finding has implications ranging from nuclear few-body systems to neutron stars and may also be observable experimentally in two-spin-state, ultracold atomic gas systems.

Health care providers' attention to food insecurity in households with children.

OBJECTIVE: To determine the extent to which physicians and nurse practitioners monitor household food insecurity (FI) of families with children, and to examine factors that influence FI monitoring. METHOD: A 2007 mail survey of family practice and pediatric physicians and nurse practitioners in the Portland, Oregon, region yielded 186 responses. Factor analysis was used to identify barriers to asking about FI. Regression analysis was used to determine whether monitoring of household food status was predicted by those barriers, attentiveness to potential FI indicators, and other variables. RESULTS: Most respondents did not routinely inquire about household FI during clinic visits. However, 88.8% expressed willingness to use a standardized screening question, if available. Monitoring of household food nutritional quality was significantly predicted by one of three identified barriers (providers' time availability). Monitoring of household food sufficiency was predicted by years in practice, attentiveness to FI indicators, and the remaining two identified barriers (inadequate knowledge about FI, discomfort in discussing FI). CONCLUSION: Routine monitoring of patients' household FI by health care providers is an underutilized strategy for reducing this condition, which poses serious risks to children's health and development. Addressing providers' concerns and introducing standardized screening procedures can increase their monitoring behaviors.

A protein interaction map of Drosophila melanogaster.

Drosophila melanogaster is a proven model system for many aspects of human biology. Here we present a two-hybrid-based protein-interaction map of the fly proteome. A total of 10,623 predicted transcripts were isolated and screened against standard and normalized complementary DNA libraries to produce a draft map of 7048 proteins and 20,405 interactions. A computational method of rating two-hybrid interaction confidence was developed to refine this draft map to a higher confidence map of 4679 proteins and 4780 interactions. Statistical modeling of the network showed two levels of organization: a short-range organization, presumably corresponding to multiprotein complexes, and a more global organization, presumably corresponding to intercomplex connections. The network recapitulated known pathways, extended pathways, and uncovered previously unknown pathway components. This map serves as a starting point for a systems biology modeling of multicellular organisms, including humans.

Tobacco use by early adolescents in Norway.

BACKGROUND: This study examined trends in the prevalence of smoking and snuff use among Norwegian adolescents in lower secondary school (ages 13-15 years) from a national survey conducted every 5 years between 1975 and 1995. METHODS: Pupils completed a brief written questionnaire on tobacco use and related information. Local school administrators coordinated data collection and forwarded a sample of completed questionnaires to the National Council on Tobacco and Health for compilation and analysis. Effects for age, gender and survey year were examined using logistic regression analysis. Overall, 24,127 pupils in five different cohorts were included. RESULTS: Smoking was highest in 1975 when 45.5% of youth reported smoking either daily or occasionally (figures adjusted for age and gender). Smoking declined each year thereafter through to 1990 (23.6%) but increased in 1995 (26.0%), primarily due to an increase in occasional smoking. Like smoking, snuff use declined between 1985 and 1990 but increased in 1995. All changes across survey years were statistically significant. Smoking was higher among girls than boys, while snuff use was much higher among boys. CONCLUSION: Several hypotheses that might account for the recent increase were examined with the most likely factor being Norway's low allocation of resources for educational interventions and public information campaigns during the years studied. However, in the past 2 years Norway has undertaken a number of new tobacco control initiatives that may result in reversal of the most recent trends.

Research on resilience and its implications for tobacco prevention.

The concept of resilience refers to successful developmental processes in children who grow up in stressful or high-risk environments. Protective factors that increase the likelihood of positive developmental outcomes, as identified by longitudinal studies, include personal-level characteristics of autonomy, self-regulation, and problem-solving skill; family characteristics of warm but demanding relationships with parents, high parental expectations, and affectionate bonds with other family members; and community characteristics of social support, effective schools, and the availability of opportunities at major life transition points. Challenges include several cross-study ambiguities in the fundamental concepts, as well as potential misapplications of this research by policymakers who believe that children can be made 'invulnerable' to environmental stressors. It is recommended that: (1) Researchers should seek to understand those cases that do not conform to predictive statistical models; clinically oriented, qualitative methodologies can be useful for this purpose. (2) Greater focus needs to be placed on identifying individual differences in children's attraction to tobacco and their motivations for use. (3) Tobacco use can be studied as an instrumental strategy on the part of adolescents for dealing with critical developmental tasks. (4) Understanding the development of stress and coping processes in children can shed light on their use of tobacco as a coping mechanism, particularly in later phases of the uptake process. Overall, the study of resilience suggests a broad lifespan view of development, in which tobacco use is just one aspect of adaptation to critical developmental tasks.

Stress reduction in child-abusing families: global and specific measures.

This study compared in-home treatment to traditional county services for their ability to reduce stress in child-abusing families. 47 families who were at risk for having at least one child removed from the home for child abuse were referred to Families First for an intensive 6-wk., in-home therapy program. A comparison group of 29 families who were also at risk for having at least one child removed for abuse received traditional county services but no in-home therapy. Stress scores used were derived from a factor analysis of the Family Inventory of Life Events and Changes (FILE) that had identified 10 stress factors. The stress data were analyzed by a series of 2 x 2 analyses of variance, group and time being the independent variables and the stress factors the dependent variables. Total stress was significantly reduced over time for both groups, and several specific stress factors were also significantly reduced over time. In secondary analyses, 2 x 3 (group by time) analyses identified interactions for total stress and three of the individual stress factors. In-home treatment was effective in reducing stress, but traditional services were also effective. Some possible explanations were discussed. A major finding was that, by including analyses using the specific stress factors (rather than just the Total Stress score), a much richer understanding of the role stress plays in abusive families is provided. It was concluded that, although global stress may be reduced by different methods, some specific types of stress are more likely to be reduced than others.

The importance of social interaction: a new perspective on social epidemiology, social risk factors, and health.

Social epidemiology research has provided persuasive evidence of the link between the social environment--especially socioeconomic status--and health outcomes, but has failed to identify underlying mechanisms that might account for the association. The research may have been limited to date by its reliance on traditional epidemiological methods that emphasize a search for specific causal factor-disease relationships. It is time to take the research evidence and recast it to find practical solutions. We argue that the human development perspective supplies a framework for understanding the critical interaction between elements of social environment and health: Analyzing the social epidemiological research from this perspective can help to explain why and how the most potent factor, socioeconomic status, affects health outcomes. Equally important, this alternative perspective also presents health education practice implications.

Macrophages (histiocytes) in various reactive and inflammatory conditions express different antigenic phenotypes.

The purpose of this study was to determine whether human tissue macrophages (M phi s) in various inflammatory/reactive conditions express different immunophenotypes. Using a large panel of monoclonal antibodies to monocyte/M phi-related antigens and a frozen-section immunoperoxidase technique, the following conditions were studied: granulomatous inflammation of unknown etiology, sarcoidosis, cat-scratch fever, toxoplasmosis, Gaucher's disease, and juvenile xanthogranulomas. The results show that there is immunophenotypic variation of the M phi s among the various inflammatory/reactive conditions. For example, the M phi s in cat-scratch fever are nearly unique in the expression of the "early inflammation" antigen identified by antibody 27E10, and the M phi s in juvenile xanthogranulomas, unlike those in most of the other conditions, lacked the antigen detected by antibody 25F9. The M phi s in Gaucher's disease differed from those in the other disorders by the combined absence of CD11b, CD14, G16/1, CD1a, CD25, and CD30. The inflammatory/reactive M phi s also exhibited differences from those in "normal" tissues, namely, a tendency toward acquisition of the antigens identified by antibodies Mac 387 and G16/1 and the more uniform expression of the "activation" antigens CD25, CD30, and CD71. The antigenic variations described here probably reflect differences in antigenic stimuli and M phi function. In addition to the possible biologic implications, this M phi immunophenotypic diversity may have practical diagnostic applications.

Comprehension of affect in context in children with pervasive developmental disorders.

Fifteen children with Pervasive Developmental Disorders (PDD) (mean age 12.7 years) were compared to mental age matched normal children on matching a context to its appropriate emotion. PDD children were slightly but significantly impaired on this task relative to a non-social task equated for difficulty. Both matching tasks were highly correlated with cognitive variables; the social matching task alone was correlated with social skill level, and neither task was correlated with ratings of social deviance. Results are discussed in terms of the demands of social cognitive tasks, the magnitude of social cognitive findings, control group selection and individual differences.

Herpes simplex virus type 2 antibodies: high prevalence in monogamous women in Costa Rica.

We studied the prevalence of antibody to Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) in 766 randomly selected Costa Rican women 25-59 years of age in a national household survey in 1984-1985. Overall, 97.1% were seropositive for HSV-1 and 39.4% for HSV-2. Only 1.1% of HSV-2 seropositive women gave a history of symptomatic genital herpes. HSV-2 virus antibody increased with age and with the number of lifetime sexual partners. HSV-2 seroprevalence among women who reported only 1 lifetime sexual partner was almost twice as high as the prevalence among women who denied sexual experience (30.5% vs. 17.7%) and reached 79.2% among women with greater than or equal to 4 partners. HSV-2 seroprevalence was lower among women whose partners used condoms: 28.9% for those who had used condoms for at least 2 years vs. 44.3% for those who never used condoms.

Affect comprehension in children with pervasive developmental disorders.

Affect comprehension was studied in children with pervasive developmental disorders (PDD) and normal children matched for mental age. Three matching tasks were used: matching objects (a nonsocial control task), matching faces, and matching affects. The three tasks were developed to be of equal difficulty for normal children. Children were also tested for comprehension and expression of affect terms. The PDD children were impaired on affect matching relative to the normal controls. The PDD children were impaired on face and affect matching relative to their own performance on object matching, whereas the normal children were not. Within the PDD sample, object matching was correlated with mental age measures but not with measures of social behavior and play, but face and affect matching were significantly correlated with mental age as well as social behavior and play. Individual PDD children who showed relative deficits on face or affect matching tended to be more socially impaired than PDD children whose face and affect matching was consonant with their mental age. Results are discussed in terms of possible etiologies of the social deficit in PDD children, and the importance of subtypes within this population.

Marketing smokeless tobacco in California communities: implications for health education.

In the first phase of a 5-year research project aimed at curtailing smokeless tobacco use among youth, we examined the marketing of smokeless tobacco within California. Observational data were collected from almost 200 retail stores located near high schools and colleges in 14 California counties. Interviews were conducted with over 100 school personnel and youth leaders in 13 counties and with seven retailers from 4 counties. Overall, 81% of the stores in the sample carried smokeless tobacco, and even in urban areas most stores (71%) had these products for sale. Urban stores were more likely to have materials promoting them (e.g., posters, displays, coupon offers). Almost all (98%) stores that carried smokeless tobacco sold moist snuff. Most (78%) school personnel and youth leaders, especially in urban areas, were aware of advertisements for it, particularly on television and in magazines. Rogers' theory regarding the diffusion of innovations was the basis of the discussion of our results. The implications of marketing for the development of health education programs are examined.

The phenotype of human placental macrophages and its variation with gestational age.

The antigenic phenotype of human villous stromal macrophages (M phi s) from first and third trimester placentas was analyzed using a large number of monoclonal antibodies (MAbs) to monocyte (Mo)/M phi-associated cell membrane determinants. The purpose of this study was to investigate M phi phenotypic heterogeneity to create a database for the correlation of M phi phenotype with specific immunologic functions. The results showed that villous stromal mononuclear cells express many cell surface antigens found on Mo and M phi s and that they are morphologically diverse, ranging in appearance from classic Hofbauer cells to spindle-shaped cells with long cytoplasmic processes. Villous stromal M phi s were the numerically dominant cell type in this structure and exhibited some major phenotypic differences from M phi s in other tissues. Comparison of first- and third-trimester placentas revealed variation in antigen expression with increasing gestational age, in particular of class II major histocompatibility complex (MHC) determinants: HLA-DR and HLA-DP antigen density was low on first-trimester villous M phi s and much higher on third-trimester M phi s while HLA-DQ was undetectable in the first trimester but present on cells in third trimester placentas. The CD1 (T6) antigen, found on Langerhans (LH) cells and cortical thymocytes, was detected on villous M phi s by two thirds of the MAbs directed against different epitopes on this determinant. Furthermore, comparison with similar studies of lymphoid tissues showed that villous M phi s and dendritic cells share the expression of a number of other cell surface antigens. Finally, it was shown that M phi s in first- and third-trimester villi exhibit strong reactivity with MAbs (Leu 3a,b) to the CD4 antigen that serves as the receptor for the human immunodeficiency virus (HIV), suggesting that these cells may be a portal of entry or reservoir for this virus in the fetuses of pregnant, HIV+ women.

Human spleen contains phenotypic subsets of macrophages and dendritic cells that occupy discrete microanatomic locations.

Macrophages (M phi s) are an important component of the immune response and mediate numerous other functions. Phenotypic and functional subsets of circulating monocytes have been described, but few similar studies have analyzed M phi s in human tissues. By use of immunohistochemical techniques and a large number of monoclonal antibodies, the presence and distribution of phenotypic subpopulations of M phi s and dendritic cells in human spleen were assessed. The results of this study show that different subsets of M phi s and dendritic cells are present in the spleen and that some of these occupy discrete microanatomic locations. In the red pulp (RP) certain groups of antigens are expressed by different proportions of uniformly distributed M phi s in the cords. On the other hand, some antigens are present on M phi s that form clusters of variable size within the red pulp. M phi s in the splenic marginal zone (MZ) share some antigens with red pulp M phi s, but in addition express CR3, Mo-2, 61D3, and 63D3. These antigens are found on only a few RP M phi s. MZ cells expressing one antigen shared with RP M phi s (Leu-3a,b) and one present largely on the MZ cells (63D3) form clusters around small vessels; these structures resemble the so-called splenic ellipsoids that may play a role in the trapping of circulating antigens. Phagocytic M phi s (tingible body M phi s) of the white pulp follicular germinal centers were also shown to differ from RP and MZ cels with respect to the expression of the antigens detected by anti-FcR, Leu-M3, Mo-2, 25F9, and anti-CR3. The unique topographical and surface antigenic features of dendritic cells were confirmed by this study. Furthermore, these cells were found to share a number of antigens with RP, MZ, and white pulp M phi s, which suggests that they may be derived from a common progenitor. The presence of phenotypic subpopulations and variation in distribution among human splenic phagocytic cells and dendritic cells may be indicative of functional specialization.

In vitro effects of human prolactin and oxytocin on sulfatase activity in isolated human decidual cells.

Homogeneous preparations of decidual cells were obtained from term decidual tissue adherent to fetal membranes by using a slightly modified version of a technique developed for the isolation of decidual cells from first and second trimester decidua. The effects of human PRL (hPRL) and oxytocin on the kinetics of the hydrolysis of estrone sulfate were determined in decidual cells prepared from tissue obtained before and after the onset of labor. In addition, sulfatase activity in decidual cells isolated from term decidua was compared with those of chorionic cells isolated from chorion leave of the same pregnancy. Chorionic cells had significantly higher (mean, 2.5-fold) levels of sulfatase activity than the corresponding decidual cells. The mean sulfatase activity in decidual cells obtained after normal vaginal delivery [25 +/- 19 (+/- SE) nmol/mg protein X 15 min) was higher than that in decidual cells obtained from patients undergoing cesarean section before the onset of labor (1.7 +/- 0.11). This difference was significant (P less than 0.02, by Mann-Whitney test) in spite of the large variation in activity in preparations from vaginal deliveries. hPRL (500 ng/ml) and oxytocin (0.2 microM) had similar effects on sulfatase activity in decidual cells in a manner dependent on whether the cells were isolated from tissue obtained before or after labor. In cells isolated from fetal membranes obtained before labor (cesarean delivery), hPRL or oxytocin significantly stimulated sulfatase activity, whereas in decidual cells obtained after vaginal delivery, both hPRL and oxytocin significantly inhibited sulfatase activity. The Michaelis constants for the hydrolysis of estrone sulfate (Km, 22 +/- 4.8 microM) were not affected by these hormones. Since the mean sulfatase activity of decidual cells obtained before labor was approximately 10-fold higher than the activity reported for endometrial stromal cells, PRL produced by decidual cells may act in vivo as an autocrine factor to stimulate their sulfatase activity.

Three-dimensional reconstructions of objects from serial sections using a microcomputer graphics system.

A computer graphics system for constructing 3-dimensional models of tissues from serial sections has been designed around a Motorola 68000 CPU. The system consists of a Dual Systems 16-bit microcomputer running the UNIX operating system. A Scion Corporation MicroAngelo color graphics system drives the color monitor. Three-dimensional imaging is enhanced by hidden line removal and area filling by color. A computer-drawn model of a cherry angioma is compared with a previously constructed physical model of the same angioma to illustrate how the system operates.

Soluble and particulate forms of rat catechol-O-methyltransferase distinguished by gel electrophoresis and immune fixation.

Catechol-O-methyltransferase (COMT) was visualized in homogenates and subcellular fractions of rat tissues, including liver and brain, by gel electrophoresis, electrophoretic transfer of proteins to nitrocellulose (Western blotting), and immune fixation with antiserum to highly purified soluble rat liver COMT. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of all tissue homogenates examined revealed three major immune-specific proteins with apparent molecular weights 23,000, 26,000, and 66,000 (23K, 26K and 66K). Centrifugation of homogenates at 100,000 X g for 60 min resulted in the enrichment of the 26K species protein in the pellet whereas the 23K and 66K proteins were the predominant forms in the supernatant. The 66K protein appeared in variable amounts depending on the tissue being examined and the length of transfer of protein and is assumed to be an "aggregate" of the smaller form(s). The 26K protein was essentially the only immunoreactive species seen in a purified preparation of rat liver outer mitochondrial membrane. Isoelectric focusing (IEF) under denaturing conditions and two-dimensional gel electrophoresis of brain and liver fractions showed that the 23K protein was resolved into three bands of pI 5.1, 5.2, and 5.3, whereas the 26K protein had a pI of 6.2. Analysis of COMT activity in slices from nondenaturing IEF gels indicated that the pI 5.1-5.3 species are biologically active; the pI 6.2 species could not be detected under these conditions. COMT activity was demonstrated, however, in outer mitochondrial membranes from rat liver, which contain predominantly the 26K, pI 6.2 immunoreactive species. The major form of COMT in all rat tissues examined is "soluble" with an apparent Mr of 23K and a pI of 5.2. The nature of the modifications giving rise to pI 5.1 and 5.3 forms of this enzyme are not clear, nor is the relationship between the 23K and 26K forms. Further studies are needed to elucidate the relationship of immunoreactive forms of COMT to each other, their intracellular location, and their functional significance.

An algorithm to improve the computational efficiency of genetic linkage analysis.

The computational complexity of genetic linkage analysis can increase exponentially with the square of the number of alleles at a marker locus. Many of the most informative marker loci have a large number of associated alleles. The precise identities of the alleles are irrelevant to the linkage analysis so long as identity-by-descent and linkage-phase information are preserved. This paper introduces an algorithm which, by relabeling, reduces the number of alleles at the marker locus, thereby increasing the speed of the analysis. The relabeling scheme preserves linkage-phase and identity-by-descent information so the results of the analysis are unaffected. Unlike previously published methods, this algorithm can be applied to pedigrees of arbitrary structure with both complete and incomplete phenotypic information.

Isolation of prolactin-producing cells from first and second trimester decidua.

Two cell types isolated and purified to homogeneity from human decidua obtained at 8-17 weeks of gestation were shown immunocytochemically to correspond to decidual and epithelial cells in the tissue of origin. The decidual cells reacted with antihuman PRL antiserum, and epithelial cells reacted with antiserum against keratin, an epithelial cell marker. Decidual and epithelial cells were cultured separately to determine their abilities to release PRL to the medium. Decidual cells released 140-410 ng PRL/mg protein in 24 h, whereas no PRL was detectable in cultures of isolated epithelial cells. These homogeneous preparations provide an excellent system with which to study the regulation of PRL production and other biochemical properties of decidual components.