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991.
ObjectiveTo determine the relative validity of three food frequency questionnaires (FFQs) compared with results from 24-hour dietary recalls for measuring dietary intakes in Guatemalan schoolchildren.DesignA cross-sectional study of primary caregivers (mothers or grandmothers) of 6–11 year-old children. Caregivers completed one of three constructed FFQs to measure the child’s dietary consumption in the last week: FFQ1 did not incorporate portion sizes; FFQ2 provided portion sizes; and FFQ3 incorporated pictures of median portion sizes. During the same week, each caregiver also completed three 24-hour dietary recalls. Results from the FFQ were compared with corresponding results from the 24-hour dietary recalls.SettingSanta Catarina Pinula, peri-urban Guatemala City.SubjectsCaregivers (n = 145) of 6–11 year-old children: 46 completed FFQ1, 49 completed FFQ2, and 50 completed FFQ3.ResultsThe mean values for all nutrients obtained from the 24-hour dietary recall were lower than for those obtained from the FFQs, excluding folic acid in FFQ3, cholesterol and zinc in FFQ2, and cholesterol, folic acid, magnesium, potassium, sodium, and zinc in FFQ1. Energy-adjusted Pearson correlation coefficients ranged from 0.07 (protein) to 0.54 (cholesterol) for FFQ1 and from 0.05 to 0.74 for FFQ2 and FFQ3. Agreement by both methods (FFQ and 24-hour dietary recalls) of classifying children into the same or adjacent quartiles of energy-adjusted nutrient consumption ranged from 62.0% for cholesterol to 95.9% for vitamin B12 across all three FFQs.ConclusionsOur FFQs had moderate to good relative validity in measuring energy and nutrient intakes for 6–11 year-old Guatemalan children. More evidence is needed to evaluate their reproducibility and applicability in similar populations.  相似文献   
992.
Abstract The thymus of the sole Solea solea contained lymphoblasts and thymocytes within a network of pale and dark epithelial cells. The pale cells were characterized by tonofilaments and desmosomes and some embraced rodlet cells within their cytoplasmic processes. The dark epithelial cells had numerous electron-dense inclusions and electron-lucent vacuoles. Lymphocytes were closely associated with the plasma membrane of both types of epithelial cells and with macrophages. Breakdown of effete lymphocytes appeared to be the main function of the macrophages. Some macrophages were multinucleated. Those containing melanin granules associated with phagosomes were classified as melanomacrophages. Pigment cells including melanophores and guanophores were present along the connective tissue trabeculae and surrounding the blood vessels. A few plasma cells and mucous cells were present.  相似文献   
993.
Hydroxyurea-resistant Aedes albopictus mosquito cells were selected by incremental exposure of unmutagenized cells to hydroxyurea concentrations ranging from 0.1 to 8 mM. Clonal populations that had become 40-fold more resistant to hydroxyurea than wild-type cells varied in morphology, and their growth rate decreased to a ∼45 h doubling time, relative to an 18 h doubling time in unselected cells. At this level of resistance, the cells remained diploid, with a modal chromosome number of 6. When labelled with 35S[methionine/cysteine], clone HU1062, which grew in the presence of 8 mM hydroxyurea, overproduced a labeled protein with the approximate size of the 45,000 dalton M2 subunit of ribonucleotide reductase. Consistent with this observation, ribonucleotide reductase activity in HU-1062 cells was approximately 10-fold higher than in wild-type control cells. This is the first example of an hydroxyurea-resistant insect cell line. © 1997 Wiley-Liss, Inc.  相似文献   
994.
995.
Homologous recombination and non-homologous end joining are two major DNA double-strand-break repair pathways. While HR-mediated repair requires a homologous sequence as the guiding template to restore the damage site precisely, NHEJ-mediated repair ligates the DNA lesion directly and increases the risk of losing nucleotides. Therefore, how a cell regulates the balance between HR and NHEJ has become an important issue for maintaining genomic integrity over time. Here we report that SIRT1-dependent KAP1 deacetylation positively regulates NHEJ. We show that up-regulation of KAP1 attenuates HR efficiency while promoting NHEJ repair. Moreover, SIRT1-mediated KAP1 deacetylation further enhances the effect of NHEJ by stabilizing its interaction with 53BP1, which leads to increased 53BP1 focus formation in response to DNA damage. Taken together, our study suggests a SIRT1-KAP1 regulatory mechanism for HR-NHEJ repair pathway choice.  相似文献   
996.
Air emissions from the U.S. pulp and paper sector have been federally regulated since 1978; however, regulations are periodically reviewed and revised to improve efficiency and effectiveness of existing emission standards. The Industrial Sectors Integrated Solutions (ISIS) model for the pulp and paper sector is currently under development at the U.S. Environmental Protection Agency (EPA), and can be utilized to facilitate multi-pollutant, sector-based analyses that are performed in conjunction with regulatory development. The model utilizes a multi-sector, multi-product dynamic linear modeling framework that evaluates the economic impact of emission reduction strategies for multiple air pollutants. The ISIS model considers facility-level economic, environmental, and technical parameters, as well as sector-level market data, to estimate the impacts of environmental regulations on the pulp and paper industry. Specifically, the model can be used to estimate U.S. and global market impacts of new or more stringent air regulations, such as impacts on product price, exports and imports, market demands, capital investment, and mill closures. One major challenge to developing a representative model is the need for an extensive amount of data. This article discusses the collection and processing of data for use in the model, as well as the methods used for building the ISIS pulp and paper database that facilitates the required analyses to support the air quality management of the pulp and paper sector.  相似文献   
997.

Objective

The detection of urinary lipoarabinomannan (LAM), a mycobacterial cell wall component, is used to diagnose tuberculosis (TB). How LAM enters the urine is not known. To investigate if urinary LAM-positivity is the result of renal TB infection we correlated the outcomes of urinary LAM-antigen testing to renal histology in an autopsy cohort of hospitalized, Ugandan, HIV-infected adults.

Methods

We performed a complete autopsy, including renal sampling, in HIV-infected adults that died during hospitalization after written informed consent was obtained from the next of kin. Urine was collected postmortem through post-mortem catheterisation or by bladder puncture and tested for LAM with both a lateral flow assay (LFA) and an ELISA assay. Two pathologists assessed the kidney histology. We correlated the LAM-assay results and the histology findings.

Results

Of the 13/36 (36%) patients with a positive urinary LAM ELISA and/or LFA, 8/13 (62%) had renal TB. The remaining 5 LAM-positive patients had disseminated TB without renal involvement. Of the 23 LAM-negative patients, 3 had disseminated TB without renal involvement. The remaining LAM-negative patients had no TB infection and died mostly of fungal and bacterial infections. LAM LFA had a sensitivity of 81% and specificity of 100% to diagnose TB at any location, and the LAM ELISA a sensitivity of 63% and a specificity of 100%. 54% (7/13) LAM LFA-positive patients were not on anti-TB treatment at the time of death.

Conclusion

Renal TB infection explained LAM-positivity in the majority of patients. Patients with disseminated TB without renal involvement can also be diagnosed with LAM. This suggests that other mechanisms that lead to urinary LAM-positivity exist in a minority of patients.  相似文献   
998.
999.
Background information. Spermatozoa are formed via a complex series of cellular transformations, including acrosome and flagellum formation, nuclear condensation and elongation and removal of residual cytoplasm. Nuclear elongation is accompanied by the formation of a unique cytoskeletal structure, the manchette. We have previously identified a leucine‐rich repeat protein that we have named TLRR (testis leucine‐rich repeat), associated with the manchette that contains a PP1 (protein phosphatase‐1)‐binding site. Leucine‐rich repeat proteins often mediate protein–protein interactions; therefore, we hypothesize that TLRR acts as a scaffold to link signalling molecules, including PP1, to the manchette near potential substrate proteins important for spermatogenesis. Results. TLRR and PP1 interact with one another as demonstrated by co‐immunoprecipitation and the yeast two‐hybrid assay. TLRR binds more strongly to PP1γ2 than it does to PP1α. Anti‐phosphoserine antibodies immunoprecipitate TLRR from testis lysate, indicating that TLRR is a phosphoprotein. TLRR is part of a complex in testis that includes cytoskeletal proteins and constituents of the ubiquitin–proteasome pathway. The TLRR complex purified from 3T3 cells contains similar proteins, co‐localizes with microtubules and is enriched at the microtubule‐organizing centre. TLRR is also detected near the centrosome of elongated, but not mid‐stage, spermatids. Conclusion. We demonstrate here that TLRR interacts with PP1, particularly the testis‐specific isoform, PP1γ2. Immunoaffinity purification confirms that TLRR is associated with the spermatid cytoskeleton. In addition, proteins involved in protein stability are part of the TLRR complex. These results support our hypothesis that TLRR links signalling molecules to the spermatid cytoskeleton in order to regulate important substrates involved in spermatid transformation. The translocation of TLRR from the manchette to the centrosome region suggests a possible role for this protein in tail formation. Our finding that TLRR is associated with microtubules in cultured cells suggests that TLRR may play a common role in modulating the cytoskeleton in other cell types besides male germ cells.  相似文献   
1000.
Twitching motility, a flagella-independent type of translocation of bacteria over moist surfaces, requires an array of proteins, including FimV. To investigate the role of this protein in twitching motility in Legionella pneumophila, we have generated a knockout mutant of fimV and characterized its phenotypic effects. In addition to a major reduction in twitching motility, deletion of the fimV gene caused a number of other phenotypic effects including decreased protective pigment formation, and it also affected cell morphology. Since fimV contains a variable number of tandem repeats, which can vary according to the origin of a given strain, we have examined the importance of this variability found within the coding region of this gene. By complementing the knockout strain with constructs containing a different number of this tandem repeat, we have been able to also show that repeat copy number is important in the functioning of this gene.  相似文献   
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