Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “collaborative cross”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,729 records · Page 96Linked to original sources
PubMed1993

Novel peroxisome clustering mutants and peroxisome biogenesis mutants of Saccharomyces cerevisiae.

The goal of this research is to identify and characterize the protein machinery that functions in the intracellular translocation and assembly of peroxisomal proteins in Saccharomyces cerevisiae. Several genes encoding proteins that are essential for this process have been identified previously by Kunau and collaborators, but the mutant collection was incomplete. We have devised a positive selection procedure that identifies new mutants lacking peroxisomes or peroxisomal function. Immunofluorescence procedures for yeast were simplified so that these mutants could be rapidly and efficiently screened for those in which peroxisome biogenesis is impaired. With these tools, we have identified four complementation groups of peroxisome biogenesis mutants, and one group that appears to express reduced amounts of peroxisomal proteins. Two of our mutants lack recognizable peroxisomes, although they might contain peroxisomal membrane ghosts like those found in Zellweger syndrome. Two are selectively defective in packaging peroxisomal proteins and moreover show striking intracellular clustering of the peroxisomes. The distribution of mutants among complementation groups implies that the collection of peroxisome biogenesis mutants is still incomplete. With the procedures described, it should prove straightforward to isolate mutants from additional complementation groups.

Acetyl-CoA C-Acetyltransferase↗
PubMed2001

Trends of HIV infection among injection drug users in Brazil in the 1990s: the impact of changes in patterns of drug use.

BACKGROUND: Santos Metropolitan Region (SMR), State of Sao Paulo, historically is well known as being one of the areas with the largest number of AIDS cases in Brazil, especially among injection drug users (IDUs). The main objective of this study was to assess the effects of changes in drug-using patterns among IDUs on trends in HIV infection among IDUs in the 1990s. METHODS: During 1991 through 1992 (wave 1; n = 214), 1994 through 1996 (wave 2; n = 135), and 1999 (wave 3; n = 108), we conducted three cross-sectional studies of IDUs. All participants were interviewed and tested for antibodies to HIV. FINDINGS: The overall sample population was 69% male, and 87% of the sample population was under 40 years old. Eighty-four percent of the population had less than 9 years of education. HIV seroprevalence was 63% in wave 1, 65% in wave 2, and 42% in wave 3 ( p <.001). Smoking of crack cocaine increased from 11% in wave 1 to 60% in wave 2 and 67% in wave 3 ( p <.001). The prevalence of frequent injections (>5 per day) decreased from 42% in wave 1 to 30% in wave 2 and 15% in wave 3 ( p <.001). INTERPRETATION: HIV prevalence decreased as injection frequency decreased and crack cocaine use increased. In SMR, patterns of drug use have been affecting the HIV epidemic more than scant public health intervention.

Adult↗
PubMed1998

A high-resolution microsatellite map of the mouse genome.

The European Collaborative Interspecific Backcross (EUCIB) resource was constructed for the purposes of high-resolution genetic mapping of the mouse genome (). The large Mus spretus/C57BL/6 backcross of 982 progeny has a genetic resolution of 0.3 cM at the 95% confidence level ( approximately 500 kb in the mouse genome). We have used the EUCIB mapping resource to develop a genome-wide high-resolution genetic map incorporating 3368 microsatellites. The microsatellites are distributed among 2302 genetically separated bins with 1.46 markers per bin on average. Average bin separation is 0.61 cM. This high-resolution genetic map will aid the construction of a robust physical map of the mouse genome.

Animals↗
PubMed2003

Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium.

We have measured the differential cross section for the gamman-->pi(-)p and gammap-->pi(+)n reactions at theta(c.m.)=90 degrees in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at E(gamma) greater, similar 3.3 GeV exhibit a global scaling behavior for both pi(-) and pi(+) photoproduction, consistent with the constituent counting rule and the existing pi(+) photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi(-) to pi(+) photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.

Journal Article↗
PubMed2000

Prazosin for Raynaud's phenomenon in progressive systemic sclerosis.

OBJECTIVES: To determine the effects and toxicity of prazosin versus placebo proposed for the treatment of Raynaud's phenomenon (RP) in scleroderma. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, and Medline up to December 1996 using the Cochrane Collaboration search strategy developed by Dickersin et al.(1994). Key words included: Raynaud's or vasospasm, scleroderma or progressive systemic sclerosis or connective tissue disease or autoimmune disease. Current Contents were searched up to and including April 7, 1997. All bibliographies of articles retrieved were searched and key experts in the area were contacted for additional and unpublished data. The initial search strategy included all languages. SELECTION CRITERIA: Randomized controlled trials comparing prazosin versus placebo were eligible if they reported clinical outcomes from the start of therapy. Trials with a greater than 35% dropout were excluded. Trials were included if patients with diffuse or limited scleroderma were the subjects. If patients with other connective tissue diseases or primary Raynaud's were included, the trial was used if the data on the scleroderma patients could be extracted from the paper. DATA COLLECTION AND ANALYSIS: All data were abstracted by two independent and trained reviewers (DF, AT), and verified by a third reviewer (JP). Each trial was assessed independently by the same two reviewers for its quality using a validated quality assessment tool (Jadad 1996). Peto's odds ratios were calculated for all dichotomous outcomes and a weighted mean difference was carried out on all continuous outcomes. Fixed effects and random effects model were used if the data was homogeneous or heterogeneous, respectively. MAIN RESULTS: Two trials with a total of 40 patients were included. Prazosin has been found in two randomized controlled cross-over trials to be more effective than placebo in the treatment of Raynaud's secondary to scleroderma. However, the positive response is modest and side effects are not rare in those taking prazosin. REVIEWER'S CONCLUSIONS: Prazosin is modestly effective in the treatment of Raynaud's phenomenon secondary to scleroderma.

Adrenergic alpha-Antagonists↗
PubMed1996

Eotaxin triggers eosinophil-selective chemotaxis and calcium flux via a distinct receptor and induces pulmonary eosinophilia in the presence of interleukin 5 in mice.

BACKGROUND: Understanding the processes that control selective eosinophilia is of fundamental importance in a variety of human diseases (e.g., allergies, parasitic infections, malignancy). Interleukin 5, an eosinophil-specific growth and activating factor, and eotaxin appear to collaborate in this process. Eotaxin is a recently described chemotactic factor that belongs to the C-C (or beta) chemokine family and has been implicated in animal and human eosinophilic inflammatory states. We have recently reported the molecular characterization of murine eotaxin and now report the biological properties of purified recombinant murine eotaxin in vitro and in vivo in the presence or absence of interleukin 5 (IL-5) in mice. MATERIALS AND METHODS: Murine eotaxin was expressed in bacteria and purified by affinity chromatography and HPLC. Activity was tested in vitro by examining chemotactic and calcium flux responses of purified murine leukocytes. Additionally, desensitization of calcium flux responses to other chemokines, eosinophil survival assays, and basophil histamine release were examined. Finally, eotaxin was delivered to wild-type or IL-5 transgenic mice and the host response was examined. RESULTS: Eotaxin had activity only when the recombinant molecule had the native mature amino terminus and contained the first 25 amino acids of the mature protein. It was active in vitro at an effective concentration between 10 and 100 ng/ml in both chemotaxis and calcium flux assays toward eosinophils, but not macrophages or neutrophils. Furthermore, intranasal or subcutaneous application of eotaxin selectively recruited large numbers of eosinophils into the mouse lung and skin, respectively, only in the presence of interleukin 5. Macrophage inflammatory protein-1 alpha, a related C-C chemokine active on eosinophils, and eotaxin were not able to cross-desensitize. Eotaxin had no affect on the in vitro survival of eosinophils and did not induce basophil histamine release. CONCLUSIONS: Mouse eotaxin is an eosinophil specific chemoattractant that has a markedly enhanced effect in vivo in the presence of another eosinophil selective cytokine IL-5, and utilizes a signal transduction receptor pathway that is distinct from that utilized by macrophage inflammatory protein-1 alpha. This data suggests that the development of tissue eosinophilia in vivo involves a two-step mechanism elicited by interleukin 5 and eotaxin.

Animals↗
PubMed1981

Characteristics of depressive patients contacting psychiatric services in four cultures. A report from the who collaborative study on the assessment of depressive disorders.

The paper is a report on results obtained in the course of a multi-centre international study on depressive disorders in four countries, which was sponsored and co-ordinated by the World Health Organization. A screen form was developed and tested in order to select depressive patients among psychiatric in-patient and out-patient populations. The patients selected in this way were assessed clinically by experienced investigators using the WHO schedule for Standardized Assessment of Depressive Disorders (SADD). A total of 53 patients were evaluated in the five research centres, and the data were utilized in uni- and multivariate statistical analyses aiming to establish whether similar cases of depression could be found in different cultures, to describe their characteristics and to ascertain the extent to which diagnostic concepts and classification categories could be applied in different settings. The results point to a considerable degree of similarity in depressive symptomatology across the cultures if particular selection criteria are applied, and suggest that broad diagnostic groupings such as 'endogenous' and 'psychogenic' depressions could be used consistently by clinicians working in different cultures.

Adult↗
PubMed1993

An international study of psychological problems in primary care. Preliminary report from the World Health Organization Collaborative Project on 'Psychological Problems in General Health Care'.

This article describes a large longitudinal multicenter collaborative study that investigated the form, frequency, course, and outcome of psychological problems that were seen in primary health care settings in 15 different sites around the world. The research employed a two-stage sampling design in which the 12-item General Health Questionnaire was administered to 26,422 persons aged 18 to 65 years who were consulting health care services. Of these persons, 5604 were selected for detailed examinations using standardized instruments and were followed up at 3 months and 1 year to provide information on course and outcome. All assessment instruments have been translated into 13 different languages. The project has produced a database that allows for the exploration of the nature of psychological disorders experienced by patients in general medical care and their association with physical illness, illness behavior, and disability over time.

Adolescent↗
PubMed1980

Features of cells controlling H-2-restricted presentation of antigen to T helper cells in vivo.

Information was sought on the nature of cells presenting antigen (sheep red blood cells) in an H-2-restricted fashion to T helper cells in vivo. The approach used was to examine the capacity of F1 hybrid T cells to collaborate with parental strain B cells after prior positive selection of the T cells to antigen in irradiated parental strain mice in the presence of various sources of Thy 1-negative cells taken from F1 or parental strain mice. The results showed that H-2-restricted presentation of antigen to T cells is controlled by radioresistant, nylon-wool adherent. Thy 1-negative cells, which are enriched in spleen and peritoneal exudates, rare in lymph node cell suspensions, and undetectable in thoracic duct lymph; pretreatment in vitro with anti-Ia reagents directed either to I-A or I-E subregion determinants abolished antigen-presenting activity. These findings correlate closely with the known characteristics of cells that present antigen in vitro. Studies in which re-irradiated parent leads to F1 chimeras were used as hosts for positive selection suggested that nonhematopoietic cells do not play a discernible role in antigen presentation.

Animals↗
PubMed1984

Collaborative study to assess risk of lung disease in Pi MZ phenotype subjects.

We studied 143 Pi MZ heterozygous (MZ) subjects from random populations that had been examined previously for alpha 1-antitrypsin phenotype. Each Pi MZ subject was closely matched with a Pi M control subject from the same population at each of 6 centers. An expanded National Heart, Lung and Blood Institute (NHLBI) respiratory symptom questionnaire was completed by each subject. Pulmonary function tests designed to detect established as well as early obstructive airway abnormalities were administered. Multivariate analysis of the variance of data from the questionnaire and pulmonary function tests corrected for age, race, sex, and smoking history showed no significant difference (p less than 0.05) between subjects of Pi MZ and Pi M phenotype. The size of the populations studied and number of observations made for each variable were sufficient to assure that small differences could be detected with 95% power. We conclude that MZ phenotype alone carries no greater risk of developing lung disease than M phenotype.

Adult↗
PubMed1990

Genetic or cultural determinants of drinking: a study of embarrassment at facial flushing among Japanese and Japanese-Americans.

Facial flushing after the ingestion of alcohol is common among Asians. Flushers are genetically less able to tolerate alcohol than nonflushers and are less likely to become alcoholics. This study examined whether lower consumption of alcohol among flushers was correlated with cultural factors such as embarrassment over flushing as well as with biological factors among Japanese in Japan and Japanese-Americans using data from a joint Japan-U.S. collaborative survey. Eight hundred forty-six Japanese and 737 Japanese-American current drinkers with known flushing status were studied. The mean alcohol intake differed significantly between groups: (1) habitat--Japanese versus Japanese-Americans, (2) flushing status--flushers versus nonflushers, and (3) embarrassment about flushing. Among men, ethnicity was the major determinant of alcohol consumption, followed by flushing status and embarrassment about flushing. Among women, differences were not significant. Lower alcohol consumption by flushers than by nonflushers has been attributed to differences in physiological reactions to alcohol. However, this study demonstrated that cultural factors such as embarrassment also contribute to lower alcohol consumption by flushers. The lack of interaction between habitat and flushing status and between habitat and embarrassment status suggests that flushing status and embarrassment status associated with drinking levels are independent of habitat.

Adult↗
PubMed1979

Physical growth in phenylketonuria: II. Growth of treated children in the PKU collaborative study from birth to 4 years of age.

Height, weight, and head circumference data up to age 4 years are reported for 124 children with phenylketonuria (PKU) who had been started on diet management before 4 months (121 days) of age and who were participating in the Collaborative Study of Children Treated for Phenylketonuria. Growth measurements of both the children and their parents corresponded with national and international standards. The growth of children with PKU was compared also with that of a group of normal children in the United States in whom corresponding longitudinal growth data had been obtained at the Fels Research Institute (FRI). Statistically significant differences betweeen the groups were not noted at any age. However, when these groups were compared on coefficients using curve fitting, a trend toward a greater increase in weight as they became older, noted in both sexes in the PKU study group, was significantly higher (P less than .005) in the PKU study girls compared with the FRI sample. Height growth was identical in both groups, and comparison with family data showed that the children with PKU grew as expected for their genetic endowment.

Body Height↗
PubMed1996

An evaluation of the history of a marijuana withdrawal syndrome in a large population.

Case reports and laboratory research indicate the existence of a cannabis withdrawal syndrome. However, the data tell us little about the prevalence and clinical characteristics of a marijuana withdrawal syndrome in people who have used the drug but who did not enter treatment for cannabis dependence. Face-to-face semi-structured interviews applying standard diagnostic criteria were used in the present study to gather data from 5611 men and women, recruited between 1991 and 1995 through the Collaborative Study of the Genetics of Alcoholism (COGA). Almost 41% of the sample had no history of marijuana use (Group 1), 28% had consumed this drug less than 21 times in any single year (Group 2), and 31% used it at least that frequently (Groups 3 and 4). Almost 16% of the more frequent marijuana users related a history of a marijuana withdrawal syndrome, and these Group 4 subjects had used the drug almost daily for an average of almost 70 months. The typical withdrawal symptoms included "nervous, tense, restlessness", "sleep disturbance" and "appetite change". While Group 4 subjects were more likely to have developed dependence on most types of drugs, even when alcohol and drug use patterns were statistically taken into account, marijuana use was still significantly related to a self-report of a history of marijuana withdrawal.

Adult↗
PubMed1990

Magnitude and patterns of family and intimate assault in Atlanta, Georgia, 1984. Collaborative Working Group for the Study of Family and Intimate Assaults in Atlanta.

A sample of police incident reports was used to examine the magnitude and patterns of family and intimate assault involving weapon use or threat, bodily force, or verbal threat of assault in a defined urban population during 1984. More than half of the incidents involved partners (spousal and nonspousal), about a fourth involved prior or estranged partners, and the remainder involved family members and relatives. The 1984 rate of nonfatal family and intimate assault was estimated at 837 per 100,000 population--the fatal rate was 7 per 100,000 population. Fatal and nonfatal victimization rates for blacks and other races were three times the rates for whites. Fatal incidents predominantly involved handguns, and nonfatal incidents most often involved bodily force. Most nonfatal victims (66%) and some perpetrators (13%) suffered physical injuries. Data on prior police contacts suggest that family and intimate assaults occur within a context of repeated violence. Information about prior incidents might contribute to preventive efforts by identifying people at high risk of being victims or perpetrators.

Cross-Sectional Studies↗
PubMed1981

Self recognition in allogeneic radiation bone marrow chimeras. A radiation-resistant host element dictates the self specificity and immune response gene phenotype of T-helper cells.

The specificity of the self-recognition repertoire in fully allogeneic (A {arrow} B), semiallogeneic (A {arrow} A x B and A x B {arrow} A), and double donor (A + B {arrow} A) radiation bone marrow chimeras was assessed by the ability of their spleen cells to generate in vitro primary plaque-forming cell (PFC) responses to trinitrophenyl- keyhole limpet hemocyanin. In contrast to spleen cells from semiallogeneic and double donor chimeras, intact spleen cells from fully allogeneic BI0 {arrow} B10.A and B10.A {arrow} B10 chimeras were not capable of generating responses to trinitrophenyl (TNP)-keyhole limpet hemocyanin. However, cultures containing a mixture of both B10 {arrow} B10.A and B10.A {arrow} B10 spleen cells did respond, demonstrating that all the cell populations required for the in vitro generation of T-dependent PFC responses were able to differentiate into functional competence in a fully allogeneic major histocompatibility complex (MHC) environment. The self recognition repertoire of T-helper cells from fully allogeneic A {arrow} B chimeras was determined to be specific for the recognition of host, not donor, MHC determinants in that they were able to collaborate with cells expressing only host MHC determinants but not with cells expressing only donor MHC determinants, even though the functional lymphocytes in these chimeras were shown to be of donor origin. Experiments utilizing double donor A + B {arrow} A chimeras further demonstrated that the ability of chimeric T cells to recognize allogeneic MHC determinants as self structures was a function of a radiation-resistant host element and not simply a consequence of the tolerization of T cell precursors to allogeneic MHC determinants, because strain A lymphocytes isolated from A + B {arrow} A chimeras were tolerant to both A and B MHC determinants but were restricted to the self recognition of syngeneic host type A MHC determinants. Finally, the Ir gene phenotype expressed by B10 {arrow} B10.A and B10.A {arrow} B10 chimeric lymphocytes was determined by their ability to function in the Ir gene controlled response to TNP-poly-L-(Tyr,Glu)-poly-D,L-Ala-poly- L-Lys [(T,G)-A--L]. The ability of lymphocytes to function in TNP-(T,G)-A--L responses was not determined by their genotype but rather paralleled the specificity of their self recognition repertoire for high responder (H-2 (b)) determinants. The possible degeneracy of the MHC-specific self recognition repertoire is discussed, and a model is proposed for Ir gene regulation in which expression of Ir gene function by lymphocytes is an antigen-nonspecific consequence of the specificity and cross-reactivity of their self recognition repertoire.

Animals↗
PubMed2001

SPINE: an integrated tracking database and data mining approach for identifying feasible targets in high-throughput structural proteomics.

High-throughput structural proteomics is expected to generate considerable amounts of data on the progress of structure determination for many proteins. For each protein this includes information about cloning, expression, purification, biophysical characterization and structure determination via NMR spectroscopy or X-ray crystallography. It will be essential to develop specifications and ontologies for standardizing this information to make it amenable to retrospective analysis. To this end we created the SPINE database and analysis system for the Northeast Structural Genomics Consortium. SPINE, which is available at bioinfo.mbb.yale.edu/nesg or nesg.org, is specifically designed to enable distributed scientific collaboration via the Internet. It was designed not just as an information repository but as an active vehicle to standardize proteomics data in a form that would enable systematic data mining. The system features an intuitive user interface for interactive retrieval and modification of expression construct data, query forms designed to track global project progress and external links to many other resources. Currently the database contains experimental data on 985 constructs, of which 740 are drawn from Methanobacterium thermoautotrophicum, 123 from Saccharomyces cerevisiae, 93 from Caenorhabditis elegans and the remainder from other organisms. We developed a comprehensive set of data mining features for each protein, including several related to experimental progress (e.g. expression level, solubility and crystallization) and 42 based on the underlying protein sequence (e.g. amino acid composition, secondary structure and occurrence of low complexity regions). We demonstrate in detail the application of a particular machine learning approach, decision trees, to the tasks of predicting a protein's solubility and propensity to crystallize based on sequence features. We are able to extract a number of key rules from our trees, in particular that soluble proteins tend to have significantly more acidic residues and fewer hydrophobic stretches than insoluble ones. One of the characteristics of proteomics data sets, currently and in the foreseeable future, is their intermediate size ( approximately 500-5000 data points). This creates a number of issues in relation to error estimation. Initially we estimate the overall error in our trees based on standard cross-validation. However, this leaves out a significant fraction of the data in model construction and does not give error estimates on individual rules. Therefore, we present alternative methods to estimate the error in particular rules.

Animals↗
PubMed2001

HIV surveillance among female sex workers.

Female sex workers are at high risk for infection with HIV, and their clients may act as a bridging population by spreading HIV to the general population. Comprehensive HIV surveillance among sex workers includes surveillance of HIV infection, of sexually transmitted infections and of risk behavior. Surveillance of HIV infection among sex workers is critical for countries with low-level or concentrated HIV epidemics, and can help in monitoring the response to the HIV epidemic in countries with a generalized epidemic. Sex workers are a vulnerable population, and particular attention needs to be paid to human rights issues including consent, confidentiality and stigma. Collaborations with key players in the local sex work scene--sex workers themselves in the first place--and alliances with salient institutions and groups are key to the success of surveillance among sex workers. Surveillance activities should have a strong link to interventions targeted at sex workers. Surveillance for HIV infection among sex workers can be institution- or community-based. Institutional settings include screening programs for registered sex workers, of sexually transmitted diseases clinics, and re-education camps. Specific sources of bias need to be considered in different settings, and must be measured--through the collection of socio-demographic and behavioral data--to allow a correct interpretation of prevalence data and time trends. Community-based HIV infection surveillance can be conducted in a probability sample of the sex worker population, thereby reducing selection bias. This requires the mapping of sex workers' contact venues, and drawing a random sample from the resulting sampling frame.

Cross-Sectional Studies↗
PubMed1990

[A registry of medullary thyroid cancer in West Germany].

A register for medullary thyroid carcinoma (MTC) in FRG has been set up by the "German Medullary Thyroid Carcinoma Study Group" in 1988. The aim is to provide a basis for collaborative work on MTC especially in the hereditary forms (i.e. multiple endocrine neoplasia [MEN] type IIa, IIb). For these hereditary varieties reliable screening tests exist and, if the disease is detected by family screening in an early stage, curative surgery is possible. Until now 408 patients (234 female, 174 male) with MTC have been reported by 17 cooperative centers. The mean age at diagnosis was 45.5 years. 25% (n = 104) are hereditary forms, most of them MEN IIa (n = 86), 13 are MEN IIb and 18 belong to the familial variety without other endocrinopathy. The mean age at diagnosis for MEN IIa was 36.5 years, MEN IIb 26.9 and for the pure familial form 27.5 years. As 33 patients per year have been diagnosed since 1982, nearly 25% of all expected cases of MTC in FRG have been registered.

Adult↗