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The human cell surface protein CD4 is not only an important accessory molecule in the activation of MHC class-II-restricted T cells, but has also been implicated to be a receptor for the human immunodeficiency virus HIV-I on lymphoid and monocytic cells. We have found that a 24-h treatment of the promonocytic leukemia cell line U937 with rIFN-gamma decreases the expression of the CD4 Ag by 50% as measured by cytofluorographic analysis. The decrease in CD4 expression was dependent on the concentration of rIFN-gamma, with maximal effects occurring at 20 to 200 U/ml. The decrease appeared to be due to actual loss of the CD4 molecule from the cell surface rather than masking of a particular epitope, inasmuch as similar results were obtained with the OKT4 and OKT4A antibodies. The effect of rIFN-gamma to decrease CD4 expression was not due to a general loss of cell surface Ag, because the binding of OKM1 and anti-HLe-1 increased after rIFN-gamma treatment. Treatment of rIFN-gamma also decreased cell surface CD4 expression on the promyelocytic leukemia cell line HL-60, and on the monocytic cell line THP-1, although the extent of the decrease was less than on U937 cells. Freshly isolated normal peripheral blood monocytes treated for 48 h with rIFN-gamma bound much less OKT4 or OKT4A antibody than cells incubated in the absence of rIFN-gamma. Moreover, treatment with rIFN-gamma reduced the percentage of peripheral blood monocytes that were positive for the CD4 Ag. In contrast with the decrease in CD4 levels on rIFN-gamma-treated monocytes, treatment with rIFN-gamma had no effect on CD4 levels on peripheral blood T lymphocytes or T cell lines.  相似文献   
24.
The various diapause and post-diapause stages entered by cabbage root fly pupae during the overwintering period are shown schematically. Although diapause induction started in mid-Aug., the early-pupating insects did not develop further but were maintained in diapause by the warm autumn temperatures. Therefore, diapause development was simultaneous in all Wellesbourne pupae, whether of second or third generation origin. Diapause development started only in mid-Oct., when mean soil temperatures fell below 10°. In the field, 90% of the overwintering population of cabbage root fly pupae had completed pleted diapause by 5 March 1980, 17 Feb. 1981 and 18 Feb. 1982. This was equivalent to a duration of 19 weeks from mid-Oct. onwards, during the winters of 1979–80, 1980–81 and 1981–82 respectively. A further break between the completion of diapause and the warm conditions required to start post-diapause development also helps to condense the emergence of flies in the spring. Hence, an accurate forecast of the time of spring attack by populations of flies similar to those at Wellesbourne should be possible.This study was financed partly by the Commission of the European Communities as CEC Contract No. 0771.  相似文献   
25.

Background

Cigarette smoking is the main risk factor for the development of chronic obstructive pulmonary disease (COPD), a major cause of morbidity and mortality worldwide. Despite this, the cellular and molecular mechanisms that contribute to COPD pathogenesis are still poorly understood.

Methodology and Principal Findings

The objective of this study was to assess IL-1 α and β expression in COPD patients and to investigate their respective roles in perpetuating cigarette smoke-induced inflammation. Functional studies were pursued in smoke-exposed mice using gene-deficient animals, as well as blocking antibodies for IL-1α and β. Here, we demonstrate an underappreciated role for IL-1α expression in COPD. While a strong correlation existed between IL-1α and β levels in patients during stable disease and periods of exacerbation, neutrophilic inflammation was shown to be IL-1α-dependent, and IL-1β- and caspase-1-independent in a murine model of cigarette smoke exposure. As IL-1α was predominantly expressed by hematopoietic cells in COPD patients and in mice exposed to cigarette smoke, studies pursued in bone marrow chimeric mice demonstrated that the crosstalk between IL-1α+ hematopoietic cells and the IL-1R1+ epithelial cells regulates smoke-induced inflammation. IL-1α/IL-1R1-dependent activation of the airway epithelium also led to exacerbated inflammatory responses in H1N1 influenza virus infected smoke-exposed mice, a previously reported model of COPD exacerbation.

Conclusions and Significance

This study provides compelling evidence that IL-1α is central to the initiation of smoke-induced neutrophilic inflammation and suggests that IL-1α/IL-1R1 targeted therapies may be relevant for limiting inflammation and exacerbations in COPD.  相似文献   
26.
Ninety patients with tuberous-sclerosis complex (TSC) were tested for subtle mutations in the TSC2 gene, by means of single-strand conformational analysis (SSCA) of genomic DNA. Patients included 56 sporadic cases and 34 familial probands. For all patients, SSCA was performed for each of the 41 exons of the TSC2 gene. We identified 32 SSCA changes, 22 disease-causing mutations, and 10 polymorphic variants. Interestingly, we detected mutations at a much higher frequency in the sporadic cases (32%) than in the multiplex families (9%). Among the eight families for which linkage to the TSC2 region had been determined, only one mutation was found. Mutations were distributed equally across the gene; they included 5 deletions, 3 insertions, 10 missense mutations, 2 nonsense mutations, and 2 tandem duplications. We did not detect an increase in mutations either in the GTPase-activating protein (GAP)-related domains of TSC2 or in the activating domains that have been identified in rat tuberin. We did not detect any mutations in the exons (25 and 31) that are spliced out in the isoforms. There was no evidence for correspondence between variability of phenotype and type of mutation (missense versus early termination). Diagnostic testing will be difficult because of the genetic heterogeneity of TSC (which has at least two causative genes: TSC1 and TSC2), the large size of the TSC2 gene, and the variety of mutations. More than half of the mutations that we identified (missense, small in-frame deletion, and tandem duplication) are not amenable to the mutation-detection methods, such as protein-truncation testing, that are commonly employed for genes that encode proteins with tumor-suppressor function.  相似文献   
27.

Objective

The purpose of this pilot study is 1) to develop an annotation schema and a training set of annotated notes to support the future development of a natural language processing (NLP) system to automatically extract employment information, and 2) to determine if information about employment status, goals and work-related challenges reported by service members and Veterans with mild traumatic brain injury (mTBI) and post-deployment stress can be identified in the Electronic Health Record (EHR).

Design

Retrospective cohort study using data from selected progress notes stored in the EHR.

Setting

Post-deployment Rehabilitation and Evaluation Program (PREP), an in-patient rehabilitation program for Veterans with TBI at the James A. Haley Veterans'' Hospital in Tampa, Florida.

Participants

Service members and Veterans with TBI who participated in the PREP program (N = 60).

Main Outcome Measures

Documentation of employment status, goals, and work-related challenges reported by service members and recorded in the EHR.

Results

Two hundred notes were examined and unique vocational information was found indicating a variety of self-reported employment challenges. Current employment status and future vocational goals along with information about cognitive, physical, and behavioral symptoms that may affect return-to-work were extracted from the EHR. The annotation schema developed for this study provides an excellent tool upon which NLP studies can be developed.

Conclusions

Information related to employment status and vocational history is stored in text notes in the EHR system. Information stored in text does not lend itself to easy extraction or summarization for research and rehabilitation planning purposes. Development of NLP systems to automatically extract text-based employment information provides data that may improve the understanding and measurement of employment in this important cohort.  相似文献   
28.

Objectives

We evaluate the potential of paired isotopic analysis of bone carbonate and collagen to examine the diet of post-medieval human and animal populations from England (17th–19th c.), including, for the first time, manufacturing towns in northern England. The potential for identifying C4 crop consumption is explored alongside regional and local patterning in diet by sex and socioeconomic status.

Materials and Methods

Humans (n = 216) and animals (n = 168) were analyzed from sites in London and northern England for both carbon and nitrogen isotopes of bone collagen (𝛿13Ccoll, 𝛿15Ncoll). Isotopic analysis of bone carbonates (𝛿13Ccarb, 𝛿18Ocarb) was carried out on all humans and 27 animals, using Fourier transform infrared spectroscopy–attenuated total reflectance to assess diagenesis.

Results

Variations in diet were observed between and within different populations by geographical location and socioeconomic status. Three pigs and one cow consumed C4 resources, indicating the availability of C4-fed animal protein. Londoners consumed more animal and marine protein and C4 resources. Middle- and upper-class populations from both London and northern populations also had greater access to these foods compared to those of lower status in the same regions.

Discussion

This substantial multi-isotope dataset deriving from bone carbonate and collagen combined from diverse post-medieval urban communities enabled, for the first time, the biomolecular identification of the dynamics of C4 consumption (cane sugar/maize) in England, providing insight into the dynamics of food globalization during this period. We also add substantially to the animal dataset for post-medieval England, providing further insight into animal management during a key moment of agricultural change.
  相似文献   
29.
Studies investigating congruent variations in species richness patterns in alpine habitats are scarce. We investigated the potential of using the indicator taxa approach for species richness in alpine habitats of the Scandes (Norway). In four areas, we investigated seven functional and taxonomic terrestrial groups of organisms and evaluated their contribution to the species diversity. The function of each group as a surrogate for the overall species diversity or for the diversity of another taxon was analysed. Three groups of invertebrates (spiders without Lycosids, Lycosids only, and ground beetles), three groups of plants (shrubs, graminoids, and herbs), and lichens were used for a cross-taxon analysis of species diversity. Congruence in species richness was restricted to several significant results, with vascular plants and spiders (Araneae) being best suited as surrogate taxa in alpine habitats of the Scandes. In the cross-taxon analyses they showed strongest significant positive correlations, covering the total species richness of the alpine habitats best. Species counts in one group account for up to 70% of the variation in total species richness. We found only limited evidence for an ideal, efficient biodiversity indicator taxon that could be applied without restrictions at different alpine habitats in low and middle alpine areas. Thus, our results suggest that it is very important to use more than one taxon as indicator for species richness in terrestrial alpine habitats. This should facilitate future conservation planning in alpine areas.  相似文献   
30.
We have employed the rapid-freeze technique to prepare specimens for electron microscopy of a coat protein solution of tobacco mosaic virus at equilibrium at pH 7.0 and 6.8, ionic strength 0.1 M and 20 degrees C. The former are the conditions for the most rapid assembly of the virus from its isolated protein and RNA. At both pH values, the equilibrium mixture contains approximately 80% of a "20 S" aggregate and 20% of a "4 S" aggregate (the so-called A-protein). The specimens were prepared either totally unstained or positively stained with methyl mercury nitrate, which binds to an amino acid residue (Cys27) internally located within the subunit, which we show not to affect the virus assembly. The images in the electron microscope are compatible only with the major structure for the "20 S" aggregate at pH 7.0 containing two rings of subunits and these aggregates display the same binding contacts as those seen between the aggregate that forms the asymmetric unit in the crystal, which has been shown by X-ray crystallography to be a disk containing two rings, each of 17 subunits, oriented in the same direction. In contrast, the images from specimens prepared at pH 6.8 show the major structure to be a proto-helix at this slightly lower pH, demonstrating that the technique of cryo-electron microscopy is capable of distinguishing between these aggregates of tobacco mosaic virus coat protein. The main structure in solution at pH 7.0 must therefore be very similar to that in the crystal, although slight differences could occur and there are probably other, minor, components in a mixture of species sedimenting around 20 S under these conditions. The equilibrium between aggregates is extremely sensitive to conditions, with a drop of 0.2 pH unit tipping the disk to proto-helix ratio from approximately 10:1 at pH 7.0 to 1:10 at pH 6.8. This direct determination of the structure of the "20 S" aggregate in solution, under conditions for virus assembly, contradicts some recent speculation that it must be helical, and establishes that, at pH 7.0, it is in fact predominantly a two-layer disk as it had been modelled before.  相似文献   
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