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Results for “Data Aggregation”

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At least 1,351 records · Page 75Linked to original sources

PubMed2004

Aggregation of embryonic stem cells induces Nanog repression and primitive endoderm differentiation.

When embryonic stem cells are allowed to aggregate, the outer layer of the aggregated spheres (referred to as embryoid bodies) differentiates into primitive endoderm. This initial specification of cell lineage facilitates further differentiation of the inner mass of the embryoid bodies. These processes are considered to recapitulate early embryonic development from the blastocyst stage to the egg-cylinder stage. Formation of the primitive endoderm layer in the embryoid bodies was induced solely by aggregation of embryonic stem cells, in the presence of leukemia inhibitory factor/STAT3 and serum/BMP4, which were considered to be sufficient for embryonic stem cell self-renewal. Interestingly, cell aggregation by itself induced Nanog repression at the outer layer, which was essential for aggregation-induced primitive endoderm formation. These data illustrate aggregation-based cell-fate specification during early embryonic development, when downregulation of Nanog plays a crucial role.

Animals↗

PubMed2005

Charged bipolar suramin derivatives induce aggregation of the prion protein at the cell surface and inhibit PrPSc replication.

The conversion of the cellular prion protein (PrPc) into a pathogenic isoform (PrP(Sc)) is one of the underlying events in the pathogenesis of the fatal transmissible spongiform encephalopathies (TSEs). Numerous compounds have been described to inhibit prion replication and PrP(Sc) accumulation in cell culture. Among these, the drug suramin induces aggregation and re-targeting of PrPc to endocytic compartments. Plasma membrane and sites of conversion into PrP(Sc) are thereby bypassed. In the present study, a library of suramin analogues was tested as a potential class of new anti-prion compounds and the molecular mechanisms underlying these effects were analysed. Treatment of prion-infected neuroblastoma cells with compounds containing symmetrical aromatic sulfonic acid substitutions inhibited de novo synthesis of PrP(Sc) and induced aggregation and reduction of the half-life of PrPc without downregulating PrPc cell surface expression. Half-molecule compounds lacking the symmetrical bipolar structure or the anionic groups had no effect on PrP(Sc) synthesis or PrPc solubility. Cell surface expression of PrPc was necessary for the activity of effective compounds. Suramin derivatives did not induce aggregation of PrPc when transport along the secretory pathway was compromised, suggesting that their effects occur at a post trans-Golgi network (TGN) site, possibly close to the compartment of conversion into PrP(Sc). In vitro studies with recombinant PrP demonstrated that the inhibitory effect correlated with direct binding to PrP and induction of insoluble PrP aggregates. Our data reveal an anti-prion effect that differs from those characterising other sulphated polyanions and is dependent on the presence of the symmetrical anionic structure of these molecules.

Animals↗

PubMed2006

UK National Audit of Early Syphilis Management. Case notes audit: diagnosis and treatment.

A national audit of 781 early syphilis cases presenting during 2002-03 in UK genitourinary medicine clinics was conducted in late 2004, organized through the Regional Audit Groups. Data were aggregated by region and National Health Service trust, allowing practice to be compared between regions, between trusts within regions, as well as to national averages and the UK National Guidelines. An enzyme immunoassay was used to diagnose 695 (89%) cases (regional range 18-100%). Use of a non-treponemal test was not recorded for 44 (6%) cases. Dark ground microscopy was used in the diagnosis of only 80 (29%) primary cases. Uptake of HIV testing was 77% (range 69-94%). Nationally, 527 (67%) treatments were parenteral, with almost equal use of benzathine penicillin G for 262 (50%, range 0-97%) cases and procaine penicillin G (PPG) for 260 cases (49%, range 3-100%). There were 14 (5%) treatments with less than the recommended 750 mg dose of PPG. One hundred and five (40%) PPG treatments were with greater than 750 mg and/or for longer than 10 days of which 76 (72%) were for early latent syphilis and/or cases with HIV infection. One hundred and ninety two (86%, range 0-100%) of all oral treatments were with doxycycline. The recommended regimen of 100 mg doxycycline twice daily for 14 days was used for 104 (53%) cases; the other 91 (47%) treatments were with a variety of regimens, mainly treatments with larger doses and/or longer treatment intervals and some combination treatments. Fourteen (2%) cases were not treated; treatment was not reported for seven (0.9%) and not known for 10 (1.3%) cases, who were treated at other centres.

Anti-Bacterial Agents↗

PubMed2001

Segregation of gangliosides GM1 and GD3 on cell membranes, isolated membrane rafts, and defined supported lipid monolayers.

Lateral assemblies of sphingolipids, glycosphingolipids and cholesterol, termed rafts, are postulated to be present in biological membranes and to function in important cellular phenomena. We probed whether rafts are heterogeneous by determining the relative distribution of two gangliosides, GM1 and GD3, in artificial supported monolayers, in intact rat primary cerebellar granule neurones, and in membrane rafts isolated from rat cerebellum. Fluorescence resonance energy transfer (FRET) using fluorophore-labelled cholera toxin B subunit (which binds GM1) and mAb R24 (which binds GD3) revealed that GM1 spontaneously self-associates but does not co-cluster with GD3 in supported monolayers and on intact neurones. Cholera toxin and immunocytochemical labelling of isolated membrane rafts from rat cerebellum further demonstrated that GM1 does not co-localise with GD3. Furthermore, whereas the membrane raft resident proteins Lyn and caveolin both co-localise with GD3 in isolated membrane rafts, GM1 appears in separate and distinct aggregates. These data support prior reports that membrane rafts are heterogeneous, although the mechanisms for establishing and maintaining such heterogeneity remain to be determined.

Animals↗

PubMed2005

Multi-step fibrinogen binding to the integrin (alpha)IIb(beta)3 detected using force spectroscopy.

The regulated ability of integrin alphaIIbbeta3 to bind fibrinogen plays a crucial role in platelet aggregation and hemostasis. We have developed a model system based on laser tweezers, enabling us to measure specific rupture forces needed to separate single receptor-ligand complexes. First of all, we performed a thorough and statistically representative analysis of nonspecific protein-protein binding versus specific alphaIIbbeta3-fibrinogen interactions in combination with experimental evidence for single-molecule measurements. The rupture force distribution of purified alphaIIbbeta3 and fibrinogen, covalently attached to underlying surfaces, ranged from approximately 20 to 150 pN. This distribution could be fit with a sum of an exponential curve for weak to moderate (20-60 pN) forces, and a Gaussian curve for strong (>60 pN) rupture forces that peaked at 80-90 pN. The interactions corresponding to these rupture force regimes differed in their susceptibility to alphaIIbbeta3 antagonists or Mn2+, an alphaIIbbeta3 activator. Varying the surface density of fibrinogen changed the total binding probability linearly >3.5-fold but did not affect the shape of the rupture force distribution, indicating that the measurements represent single-molecule binding. The yield strength of alphaIIbbeta3-fibrinogen interactions was independent of the loading rate (160-16,000 pN/s), whereas their binding probability markedly correlated with the duration of contact. The aggregate of data provides evidence for complex multi-step binding/unbinding pathways of alphaIIbbeta3 and fibrinogen revealed at the single-molecule level.

Binding Sites↗

PubMed2005

Primary operative versus nonoperative therapy for pediatric empyema: a meta-analysis.

OBJECTIVE: The optimal treatment of children with empyema remains controversial. The purpose of this review was to compare reported results of nonoperative and primary operative therapy for the treatment of pediatric empyema. METHODS: A systematic comprehensive review of the scientific literature was conducted with the PubMed (National Library of Medicine) database for the period from 1981 to 2004. This reproducible search identified all publications dealing with treatment of empyema in the pediatric population (<18 years of age). A meta-analysis was performed with studies with adequate data summaries for > or =1 of the outcomes of interest for both treatment groups. RESULTS: Sixty-seven studies were reviewed. Data were aggregated from reports of children initially treated nonoperatively (3418 cases from 54 studies) and of children treated with a primary operative approach (363 cases from 25 studies). The populations were similar in age. Patients who underwent primary operative therapy had a lower aggregate in-hospital mortality rate (0% vs 3.3%), reintervention rate (2.5% vs 23.5%), length of stay (10.8 vs 20.0 days), duration of tube thoracostomy (4.4 vs 10.6 days), and duration of antibiotic therapy (12.8 vs 21.3 days), compared with patients who underwent nonoperative therapy. In 8 studies for which meta-analysis was possible, patients who received primary operative therapy were found to have a pooled relative risk of failure of 0.09, compared with those who did not. Meta-analysis could not be performed for any of the other outcome measures investigated in this review. Similar complication rates were observed for the 2 groups (5% vs 5.6%). CONCLUSIONS: These aggregate results suggest that primary operative therapy is associated with a lower in-hospital mortality rate, reintervention rate, length of stay, time with tube thoracostomy, and time of antibiotic therapy, compared with nonoperative treatment. The meta-analysis demonstrates a significantly reduced relative risk of failure among patients treated operatively.

Adolescent↗

PubMedDate not supplied

[Mortality due to infectious and parasitic diseases in Salvador, Bahia: evolution and intra-urban differences according to living conditions].

The evolution of mortality due to infectious and parasitic diseases (IPD) and its intra-urban distribution in Salvador (Bahia) during the 1990's was analyzed in a study of time series and spatial aggregation. This data was obtained from DATASUS and from death certificates. Proportional mortality, mortality rate and standardized mortality ratio (SMR) were used for the temporal analysis. Mortality rates due to IPD stratified by a living conditions index (LCI) were analyzed in the spatial study. Between 1991 and 1995, the proportional mortality for IPD was 8.3% and the risk of dying varied between 55.9 and 34.0/100,000 inhabitants. After 1995 the variation was between 52.8 and 41.1/100,000 inhabitants. The standardized mortality ratio for infectious and parasitic diseases in 1998 was 1.3. Infectious intestinal diseases continue to be one of the principal causes of death in this group. The highest rates of mortality from IPD were concentrated in the areas of the city where the living conditions were poor. Despite the observed decline, there is still an excessive mortality rate from IPD in Salvador. The developmental model of the Country and re-emergence of some diseases could be contributing towards this pattern.

Brazil↗

PubMed2005

Prostanoids modulate inflammation and alloimmune responses during graft rejection.

Acute rejection of a transplanted organ is characterized by intense inflammation within the graft. Yet, for many years transplant researchers have overlooked the role of classic mediators of inflammation such as prostaglandins and thromboxane (prostanoids) in alloimmune responses. It has been demonstrated that local production of prostanoids within the allograft is increased during an episode of acute rejection and that these molecules are able to interfere with graft function by modulating vascular tone, capillary permeability, and platelet aggregation. Experimental data also suggest that prostanoids may participate in alloimmune responses by directly modulating T lymphocyte and antigen-presenting cell function. In the present paper, we provide a brief overview of the alloimmune response, of prostanoid biology, and discuss the available evidence for the role of prostaglandin E2 and thromboxane A2 in graft rejection.

Acute Disease↗

PubMed1994

Flow-cytometric identification and detection of Porphyromonas gingivalis by a LPS specific monoclonal antibody.

The purpose of this study was to identify Porphyromonas gingivalis (P. gingivalis) by flow cytometry (FCM) using a monoclonal antibody (MAb) OMR-Bg1E directed to P. gingivalis-specific lipopolysaccharide (LPS). The P. gingivalis strains ATCC 33277, 381, ESO75, W50, and A7A1 were selected for the study. Fusobacterium nucleatum (F. nucleatum), Prevotella intermedia (P. intermedia), Campylobacter rectus (C. rectus), Streptococcus sanguis (S. sanguis) and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) served as controls. A suspension of 10(7) bacteria/ml of each bacteria was prepared and then reacted with a P. gingivalis specific MAb OMR-Bg1E and fluorescein isothiocyanate (FITC) labeled second antibody. These samples were analyzed by FCM. Bacterial specific binding aggregate on data was separated out by the forward- and side-angle-scatter characteristics, while non-specific binding (NSB) was eliminated by excluding the region with mouse IgG-positive and second antibody-positive area. FCM detected a mean range of 56.2% to 97.2% P. gingivalis strains. There was a 5.1% non-specific binding using FCM to non-P. gingivalis strains. When the P. gingivalis concentration was adjusted to 10(2), 10(4), and 10(6) bacteria/ml, a detection rate of 35.7%, 48.1%, and 91.4%, was respectively observed. The lower sensitivity of the flow cytometric assay was 10(2) bacteria/ml. When P. gingivalis was added to P. intermedia suspension at 1, 20, 40, 60, and 80%, the MAb-positive fraction yielded by FCM displayed a coefficient of determination of 0.967 with the actual percentage of P. gingivalis and could be regressed to a linear function.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed2001

Trends in HIV testing among pregnant women: United States, 1994-1999.

OBJECTIVES: This study evaluated 1995 guidelines for HIV testing of pregnant women. METHODS: Analysis focused on Behavioral Risk Factor Surveillance System data for the years 1994 through 1999. Data were aggregated across states. RESULTS: Percentages of pregnant women tested for HIV increased from 1995 to 1996 (from 41% to 53%) and again from 1997 (52%) to 1998 (60%). CONCLUSIONS: After implementation of the guidelines, the percentage of pregnant women tested for HIV increased, although nearly half had not been tested. More efforts are needed to encourage women to undergo testing for HIV during pregnancy, thus maximizing opportunities for offering antiretroviral therapy.

AIDS Serodiagnosis↗

PubMed2004

Effects of macroeconomic trends on social security spending due to sickness and disability.

OBJECTIVES: We analyzed the relationship between macroeconomic conditions, measured as unemployment rate and social security spending, from 4 social security schemes and total spending due to sickness and disability. METHODS: We obtained aggregated panel data from 13 Organization for Economic Cooperation and Development member countries for 1980-1996. We used regression analysis and fixed effect models to examine spending on sickness benefits, disability pensions, occupational-injury benefits, survivor's pensions, and total spending. RESULTS: A decline in unemployment increased sickness benefits spending and reduced disability pension spending. These effects reversed direction after 4 years of unemployment. Inclusion of mortality rate as an additional variable in the analysis did not affect the findings. CONCLUSIONS: Macroeconomic conditions influence some reimbursements from social security schemes but not total spending.

Accidents, Occupational↗

PubMed2005

COX-2 selective inhibitors in the treatment of arthritis: a rheumatologist perspective.

COX-2 selective inhibitors were developed in order to provide similar efficacy to traditional nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) but with improved upper gastrointestinal safety. This paper presents an overview of randomized clinical trials demonstrating the efficacy of COX-2 selective inhibitors for the treatment of patients with arthritis, particularly osteoarthritis and rheumatoid arthritis. In osteoarthritis and rheumatoid arthritis, COX-2 selective inhibitors have been shown to be more effective than placebo and similarly effective as standard doses of nonselective NSAIDs. There are currently few randomized clinical trials comparing the efficacy of the 2 first-generation COX-2 selective inhibitors, celecoxib and rofecoxib, in osteoarthritis. Of 4 head-to-head studies comparing the 2 agents, 3 indicated similar efficacy, while the other demonstrated superiority of rofecoxib at a dose of 25 mg qd compared with celecoxib at a dose of 200 mg qd. There are no clinical trials comparing the efficacy of different agents for treatment of patients with rheumatoid arthritis. Some studies have also demonstrated efficacy for COX-2 selective inhibitors in patients with ankylosing spondylitis and gout. In aggregate, these data show that COX-2 selective inhibitors provide effective relief of pain in patients with osteoarthritis and rheumatoid arthritis, with efficacy that is similar to traditional NSAIDs. Cost-effectiveness and cost-utility studies suggest, however, that their use should be limited to patients at high risk of serious upper gastrointestinal side effects, including complicated ulcers.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1993

How socioeconomic status affects birth and death rates in rural Kerala, India: results of a health study.

Data relating to birth and death were collected from throughout the state of Kerala, India, in a health survey conducted by the Kerala Sastra Sahitya Parishad, a voluntary organization. In this study, the authors analyze birth and death rates as calculated from the sample of 9,940 households (57,665 persons), with respect to other variables such as region, religion, and socioeconomic status. In order to study the effect of socioeconomic factors on birth and death rates, a socioeconomic status rating (SES rating) was developed, taking into account such factors as income, education, housing conditions, and land ownership. Socioeconomic status was found to have a definite influence on birth and death rates, with higher socioeconomic status resulting in lower birth and death rates. This effect was independent of such confounding variables as age structure of the population, religion, and region. The higher risk of mortality among the poorer households can partly be explained by the material deprivation: the higher birth rates could be the result of poorer educational attainments.

Adolescent↗

PubMed1994

Assessment of diabetes care by medical record review. The Indian Health Service model.

OBJECTIVE: To evaluate the adherence to minimum standards for diabetes care in multiple primary-care facilities using a uniform system of medical record review. RESEARCH DESIGN AND METHODS: In 1986, the Indian Health Service (IHS) developed diabetes care standards and an assessment process to evaluate adherence to those standards using medical record review. We review our assessment method and results for 1992. Charts were selected in a systematic random fashion from 138 participating facilities. Trained professional staff reviewed patient charts, using a uniform set of definitions. A weighted rate of adherence was constructed for each item. RESULTS: Medical record reviews were conducted on 6,959 charts selected from 40,118 diabetic patients. High rates of adherence (> 70%) were noted for blood pressure and weight measurements at each visit, blood sugar determinations at each visit, annual laboratory screening tests, electrocardiogram at baseline, and adult immunizations. Lower rates of adherence (< or = 50%) were noted for annual eye, foot, and dental examinations. CONCLUSIONS: IHS rates of adherence are similar to rates obtained from medical record reviews and computerized billing data, but are less than rates obtained by provider self-report. Medical record review, using uniform definitions and inexpensive software for data entry and reports, can easily be implemented in multiple primary-care settings. Uniformity of data definition and collection facilitates the aggregation of the data and comparison over time and among facilities. This medical record review system, although labor intensive, can be easily adopted in a variety of primary-care settings for quality improvement activities, program planning, and evaluation.

Adolescent↗

PubMed2001

Surveillance of sexually transmitted infections in England and Wales.

Surveillance of sexually transmitted infections (STIs) in England and Wales has, in the past, relied principally on aggregated statistical data submitted by all genitourinary medicine clinics to the Communicable Disease Surveillance Centre, supplemented by various laboratory reporting systems. Although these systems provide comparatively robust surveillance data, they do not provide sufficient information on risk factors to target STI control and prevention programmes appropriately. Over recent years, substantial rises in STIs, the emergence of numerous outbreaks of STIs, and changes in gonococcal resistance patterns have necessitated the introduction of more sophisticated surveillance mechanisms. This article describes current STI surveillance systems in England and Wales, including new systems that have recently been introduced or are currently being developed to meet the need for enhanced STI surveillance data.

Chlamydia Infections↗

PubMed1985

Temporal pattern effects on auditory evoked potentials.

The question whether stimuli forming temporal patterns are processed differently from identical stimuli belonging to irregular temporal aggregates was investigated. Tones forming either regular or irregular triads were presented to eight normal subjects. The N1-P2 amplitude of evoked potentials to tones forming temporal patterns were consistently lower than those to tones in the irregular aggregates. These data indicate that the perceptual phenomenon of subordination of constituent parts to a well-formed whole is demonstrable in electrophysiological terms.

Adult↗

PubMedDate not supplied

Rehabilitation service utilization models: changes in the opportunity structure for disabled women.

The focus of this paper is the opportunity structure for rehabilitation and subsequent outcome for disabled women, in comparison with disabled men. From evidence cited in the literature the differential provision of rehabilitation and other supportive services to disabled women suggests variation in outcome, based on two analytic service utilization models of rehabilitation: medical and psychosocial. Aggregate trend data (1972 and 1978) were used in the analysis of adult disabled groups, by gender and selected disabling conditions. There are two striking results from the analysis of these data sets. One indicates that receipt of rehabilitation is greatly influenced by sociodemographic factors, particularly gender and age. A detailed examination of the combination effects of gender and other sociodemographic variables shows that there are subtleties, such as an interaction between race and gender and education and gender, as well as between age and gender, that put uneducated, younger, white women at a disadvantage in their access to rehabilitation resources. The analysis of these sociodemographic factors over two points in time, however, demonstrates what can be considered a diffusion of the distinctions of social inequality, probably due to changes in rehabilitation legislation that redefined eligibility criteria for rehabilitation services and expanded programme goals. The second result of note is that neither form of rehabilitation is associated with a positive outcome, in this case ability to work. In the earlier data set (1972), indications were that neither the medical model of rehabilitation nor the psychosocial model were effective in returning the individual to the work role. This was true for both men and women.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

[Age differences in platelet aggregation, plasma levels of prostanoid, cyclic nucleotide and lipids in Japanese].

Platelet aggregation induced by adenosine diphosphate (ADP), adrenaline and collagen was studied in various age groups of healthy Japanese. Plasma levels of prostanoid, cyclic nucleotide and lipid (triglyceride and cholesterol) were investigated. Platelet aggregation in females was rather high in all groups compared with males in each age group, although there was no statistical difference. Age dependent increase was not observed. Platelet aggregation response to 1 gamma of adrenaline was either high or low and the levels of collagen-induced platelet aggregation in the low responder group was also significantly lower than those of the high responder group. Positive correlation was obtained between ADP-induced platelet aggregation and serum cholesterol levels. These data suggest platelet aggregation was not influenced by aging but other biochemical or physical conditions of individuals.

Adolescent↗