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排序方式: 共有1124条查询结果,搜索用时 15 毫秒
941.
Zehra Jamil Najeeha Talat Iqbal Romana Idress Zubair Ahmed Kamran Sadiq Indika Mallawaarachchi Junaid Iqbal Sana Syed Aneeta Hotwani Furqan Kabir Kumail Ahmed Sheraz Ahmed Fayaz Umrani Jennie Z. Ma Fatima Aziz Adil Kalam Sean R. Moore Syed Asad Ali 《PLoS neglected tropical diseases》2021,15(7)
Environmental enteric dysfunction (EED) is a subclinical condition of intestinal inflammation, barrier dysfunction and malabsorption associated with growth faltering in children living in poverty. This study explores association of altered duodenal permeability (lactulose, rhamnose and their ratio) with higher burden of enteropathogen in the duodenal aspirate, altered histopathological findings and higher morbidity (diarrhea) that is collectively associated with linear growth faltering in children living in EED endemic setting. In a longitudinal birth cohort, 51 controls (WHZ > 0, HAZ > −1.0) and 63 cases (WHZ< -2.0, refractory to nutritional intervention) were recruited. Anthropometry and morbidity were recorded on monthly bases up to 24 months of age. Dual sugar assay of urine collected after oral administration of lactulose and rhamnose was assessed in 96 children from both the groups. Duodenal histopathology (n = 63) and enteropathogen analysis of aspirate via Taqman array card (n = 60) was assessed in only cases. Giardia was the most frequent pathogen and was associated with raised L:R ratio (p = 0.068). Gastric microscopy was more sensitive than duodenal aspirate in H. pylori detection. Microscopically confirmed H. pylori negatively correlated with HAZ at 24 months (r = −0.313, p = 0.013). Regarding histopathological parameters, goblet cell reduction significantly correlated with decline in dual sugar excretion (p< 0.05). Between cases and controls, there were no significant differences in the median (25th, 75th percentile) of urinary concentrations (μg/ml) of lactulose [27.0 (11.50, 59.50) for cases vs. 38.0 (12.0, 61.0) for controls], rhamnose [66.0 (28.0, 178.0) vs. 86.5 (29.5, 190.5)] and L:R ratio [0.47 (0.24, 0.90) vs. 0.51 (0.31, 0.71)] respectively. In multivariable regression model, 31% of variability in HAZ at 24 months of age among cases and controls was explained by final model including dual sugars. In conclusion, enteropathogen burden is associated with altered histopathological features and intestinal permeability. In cases and controls living in settings of endemic enteropathy, intestinal permeability test may predict linear growth. However, for adoption as a screening tool for EED, further validation is required due to its complex intestinal pathophysiology. 相似文献
942.
Nussenzveig Daniel R.; Matos Maria De Fatima C.; Thaw Colette N. 《American journal of physiology. Cell physiology》1998,275(5):C1264
The human calcitonin receptor (hCTR) is expressed in polarizedcells of the kidney, bone, and nervous system. In the kidney, hCTRs arefound in cells of the distal nephron to which blood-borne calcitoninhas access only at the basolateral surface. We expressed hCTR subtypes1 and 2 in Madin-Darby canine kidney (MDCK) cells to establish a cellmodel useful for delineating the molecular mechanisms underlying hCTRpolarity. Selective cell surface incubation demonstrated functionalpolarity of hCTRs by equilibrium binding or cross-linking ofradioiodinated salmon calcitonin(125I-sCT) and cAMP accumulationstimulated by sCT. We estimated that at the steady state there are40-fold more hCTRs on the basolateral than on the apical side.Domain-selective cell surface biotinylation followed by immunoblottingof streptavidin-agarose-fractionated biotinylated glycoproteinsindependently confirmed the polarized distribution of FLAGepitope-tagged hCTR-2 in the basolateral domain. Confocal microscopy ofimmunostained receptors revealed that hCTRs are concentrated on alateral subdomain of the basolateral membrane. Cell surface arrivalassay of newly formed receptors demonstrated that direct delivery tothe basolateral domain is the mechanism by which hCTRs becomepolarized. Measurement of receptor turnover on the basolateral surfaceshowed that retention contributes to hCTR distribution at the steadystate. 相似文献
943.
Regulation of Glycerol Phosphate Dehydrogenase and Lactate Dehydrogenase Activity by Forskolin and Dibutyryl Cyclic AMP in the C6 Glial Cells 总被引:3,自引:2,他引:1
We have compared the effects of norepinephrine, forskolin, and dibutyryl cyclic AMP (Bt2cAMP) on the regulation of the cytosolic enzyme glycerol phosphate dehydrogenase (GPDH) in the C6 rat glioma cell line. Forskolin and Bt2cAMP elicit a dose-dependent increase in the levels of the enzyme that was, however, unaffected by norepinephrine. The half-maximal effect of forskolin was obtained at 7-8 microM, and the effect was maximal at 30 microM. Dexamethasone at a 50 nM concentration produced a two- to sixfold induction of GPDH after 48 h. The combination of dexamethasone with forskolin or Bt2cAMP leads to an elevation in GPDH levels that is higher than that produced by one of the compounds alone. This potentiation is found when both agents are added together with or after the glucocorticoid. The increase in uninduced and dexamethasone-induced GPDH activity was blocked by cycloheximide and actinomycin D, indicating that de novo protein and RNA synthesis are required. The activity of cytosolic lactate dehydrogenase activity did not change after incubation with dexamethasone, but increased with forskolin or Bt2cAMP. 相似文献
944.
Frederick H. Kasten L. Fatima R. Pineda Paul E. Schneider H. Ralph Rawls Theda A. Foster 《In vitro cellular & developmental biology. Plant》1989,25(1):57-62
Summary Cell culture is a valuable method of evaluating the biocompatibility of new dental materials. The purpose of this study was
to compare the in vitro biocompatibility of an experimental fluoride composite resin with fluoride and non-fluoride-releasing
materials currently available. The dental materials tested were: MQ Silicate (silicate cement), KETAC-CEM and FUJI (type II
glass ionomer cements), VISIO DISPERS (a light-cured, nonfluoridated, microfilled composite resin), and FR-17 (an experimental
fluoride-releasing composite resin). The Smulow-Glickman (S-G) human, gingival epithelial cell line, which exhibits semidifferentiated
characteristics, was used in the study as a test system. Biocompatibility was quantified by counting the viable cells per
unit area remaining after 24 and 48 h at two radial distances from cured specimens immersed in the cell culture medium. The
test materials were observed to be most toxic to cells nearest the materials. A Time-Distance Cytotoxicity Index (TDCI) was
calculated to relate the percentage of dead cells to viable cells at each diffusion distance for each exposure time compared
to a nontoxic control. The relative toxicity ranking of the materials tested based on the TDCI was VISIO DISPERS (91%), FUJI
(82%), FR-17 (30%), MQ Silicate (23%), and KETAC-CEM (10%), which exhibited the least toxicity. The cytotoxicity of the experimental
resin FR-17 was within the range of cytotoxicity of currently accepted restorative materials.
this study was supported in part by grant R01-DE04749 from the National Institutes of Health, Bethesda, MD, to H. R. R., and
by grant no. S07-RR05704-13 from the Biomedical Research Grant Program, Division of Research Resources, National Institutes
of Health, awarded to the Louisiana State University School of Dentistry. 相似文献
945.
The phenotype and frequency of cells in normal human peripheral blood spontaneously secreting IL-2, IL-4, IL-6, IL-10, IFN and TNF-α ex vivo was determined using ELIspot assays. CD4+T cells were the dominant source of IL-2 and IL-4 while multiple cell types (primarily CD8+lymphocytes) produced IFN. Fewer than 0.05% of mononuclear cells were spontaneously secreting these T cell derived factors. By comparison, IL-6, IL-10 and TNF-α were produced by 0.7–20% of PBMC. The primary sources of the latter cytokines were CD14+macrophages/monocytes. A significant positive correlation was found in the frequency of cells secreting IL-6, IL-10 and TNF-α ex vivo, suggesting that the release of such factors was coordinately regulated. No such correlation was found among IL-2, IL-4 and IFN secreting cells, indicating that the production of predominantly T cell derived cytokines was regulated independently. 相似文献
946.
David Schlessinger Randy D. Little Diha Freije Fatima Abidi Ileana Zucchi Giovanni Porta Giuseppe Pilia Ramaiah Nagaraja Sandra K. Johnson Jae-Young Yoon Anand Srivastava Juha Kere Giuseppi Palmieri Alfredo Ciccodicola Vittorio Montanaro Giovanna Romano Amelia Casamassimi Michele D'Urso 《Genomics》1991,11(4)
Yeast artificial chromosomes (YACs) have recently provided a potential route to long-range coverage of complex genomes in contiguous cloned DNA. In a pilot project for 50 Mb (1.5% of the human genome), a variety of techniques have been applied to assemble Xq24–q28 YAC contigs up to 8 Mb in length and assess their quality. The results indicate the relative strength of several approaches and support the adequacy of YAC-based methods for mapping the human genome. 相似文献
947.
Fatima Cvrčková 《Applied microbiology and biotechnology》1991,35(4):515-516
Summary A new selection method based on the use of chlorsulfuron (CS) resistance as the selection marker for protoplast fusion in industrial yeast has been introduced using the system of protoplast fusion. A petite mutant of a spontaneously CS-resistant distiller's Saccharomyces cerevisiae strain and a wild-type CS-sensitive strain of the osmotolerant yeast Zygosaccharomyces mellis were fused in order to obtain a distiller's yeast suitable for fermentations on concentrated molasses. Fusion products were isolated as large colonies on minimal glycerol agar with 0.5 mg ml–1 of the herbicide Glean (75% CS). Following prolonged cultivation on molasses, stable hybrid subxlones were obtained.
Offprint requests to: F. Cvrková 相似文献
948.
Pfeiffer Fatima; Sternfeld Lutz; Schmid Andreas; Schulz Irene 《American journal of physiology. Cell physiology》1998,274(3):C663
We haveinvestigated control mechanisms involved in the propagation ofagonist-induced Ca2+ waves inisolated mouse pancreatic acinar cells. Using a confocal laser-scanningmicroscope, we were able to show that maximal stimulation of cells withacetylcholine (ACh, 500 nM) or bombesin (1 nM) caused an initialCa2+ release of comparable amountswith both agonists at the luminal cell pole. SubsequentCa2+ spreading to the basolateralmembrane was faster with ACh (17.3 ± 5.4 µm/s) than with bombesin(8.0 ± 2.2 µm/s). The speed of bombesin-inducedCa2+ waves could be increased upto the speed of ACh-induced Ca2+waves by inhibition of protein kinase C (PKC). Activation of PKCsignificantly decreased the speed of ACh-inducedCa2+ waves but had only littleeffect on bombesin-evoked Ca2+waves. Within 3 s after stimulation, production of inositol1,4,5-trisphosphate [Ins(1,4,5)P3]was higher in the presence of ACh compared with bombesin, whereasbombesin induced higher levels of diacylglycerol (DAG) than ACh. Thesedata suggest that the slower propagation speed of bombesin-inducedCa2+ waves is due to higheractivation of PKC in the presence of bombesin compared with ACh. Thehigher increase in bombesin- compared with ACh-induced DAG productionis probably due to activation of phospholipase D (PLD). Inhibition ofthe PLD-dependent DAG production by preincubation with 0.3% butanolled to an acceleration of the bombesin-induced Ca2+ wave. In further experiments,we could show that ruthenium red (100 µM), an inhibitor ofCa2+-inducedCa2+ release in skeletal muscle,also decreased the speed of ACh-induced Ca2+ waves. The effect ofruthenium red was not additive to the effect of PKC activation. Fromthe data, we conclude that, following Ins(1,4,5)P3-inducedCa2+ release in the luminal cellpole, secondary Ca2+ release fromstores, which are located in series between the luminal and the basalplasma membrane, modifies Ca2+spreading toward the basolateral cell side byCa2+-inducedCa2+ release. Activation of PKCleads to a reduction in Ca2+release from these stores and therefore could explain the slower propagation of Ca2+ waves in thepresence of bombesin compared with ACh. 相似文献
949.
I-SceI-Induced Gene Replacement at a Natural Locus in Embryonic Stem Cells 总被引:4,自引:0,他引:4 下载免费PDF全文
Michel Cohen-Tannoudji Sylvie Robine Andr Choulika Daniel Pinto Fatima El Marjou Charles Babinet Daniel Louvard Frdric Jaisser 《Molecular and cellular biology》1998,18(3):1444-1448
Gene targeting is a very powerful tool for studying mammalian development and physiology and for creating models of human diseases. In many instances, however, it is desirable to study different modifications of a target gene, but this is limited by the generally low frequency of homologous recombination in mammalian cells. We have developed a novel gene-targeting strategy in mouse embryonic stem cells that is based on the induction of endogenous gap repair processes at a defined location within the genome by induction of a double-strand break (DSB) in the gene to be mutated. This strategy was used to knock in an NH2-ezrin mutant in the villin gene, which encodes an actin-binding protein expressed in the brush border of the intestine and the kidney. To induce the DSB, an I-SceI yeast meganuclease restriction site was first introduced by gene targeting to the villin gene, followed by transient expression of I-SceI. The repair of the ensuing DSB was achieved with high efficiency (6 × 10−6) by a repair shuttle vector sharing only a 2.8-kb region of homology with the villin gene and no negative selection marker. Compared to conventional gene-targeting experiments at the villin locus, this represents a 100-fold stimulation of gene-targeting frequency, notwithstanding a much lower length of homology. This strategy will be very helpful in facilitating the targeted introduction of several types of mutations within a gene of interest. 相似文献
950.
Affinity precipitation is a technique that imparts selectivity to the widely used primary purification step of precipitation
of proteins from crude extracts. Hetero-bifunctional affinity precipitation involves use of reversibly soluble/insoluble polymers
that can be used as backbones to conjugate affinity ligands for specific separations. A variety of such polymers have been
reported in literature. In this work we report development of carboxymethyl cellulose (CM cellulose) as a cheap, readily available
and versatile reversibly soluble polymer system. Available CM cellulose as sodium salt could be quantitatively precipitated
from its aqueous solution in presence of about 50 mM calcium and 7.2% w/v polyethylene glycol-4000, and could be resolubilised
in the working buffer in absence of calcium, polyethylene glycol or both. Effectiveness of the CM cellulose-calcium-polyethylene
glycol system was demonstrated by purifying lactate dehydrogenase from porcine muscle extractusing covalently conjugated Cibacron
blue dye-ligand. By careful choice of conditions that suppressed non-specific interactions, the system was shown to be an
effective affinity precipitation polymer system inspite of the polyelectrolytic nature of CM cellulose. Up to 23 fold purification
of the enzyme from crude extarct was obtained in one single precipitation sequence.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献