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991.
Band 3 Courcouronnes (Ser667Phe): a trafficking mutant differentially rescued by wild-type band 3 and glycophorin A 总被引:2,自引:0,他引:2
Toye AM Williamson RC Khanfar M Bader-Meunier B Cynober T Thibault M Tchernia G Déchaux M Delaunay J Bruce LJ 《Blood》2008,111(11):5380-5389
We describe a mutation in human erythrocyte band 3 (anion exchanger 1; SLC4A1) causing both hereditary spherocytosis and distal renal tubular acidosis. The proband developed a transfusion-dependent, hemolytic anemia following birth. Immunoblotting showed band 3 was reduced to approximately 35% of wildtype; other proteins of the band 3/Rh macrocomplex were also reduced. DNA sequence analysis revealed a novel homozygous mutation, c.2000C>T, leading to the amino acid substitution Ser667Phe. The parents were heterozygous for the same mutation. Sulfate influx in the patient's erythrocytes was approximately 40% wild type. The mutant band 3 produced very little chloride influx when expressed in Xenopus oocytes. Influx was partially rescued by coexpression of glycophorin A and also rescued by coexpression of wild-type band 3. At 2 years of age, an ammonium chloride challenge showed the child has incomplete distal renal tubular acidosis (dRTA). Stable expression of mutant kidney band 3 in both nonpolarized and polarized Madin-Darby canine kidney cells showed that most of the mutant protein was retained in the endoplasmic reticulum. Overall our results suggest that the Ser667Phe does not affect the anion transport function of band 3, but causes a trafficking defect in both erythrocytes and kidney cells. 相似文献
992.
Repetitive increases in cytosolic Ca2+ of guard cells by abscisic acid activation of nonselective Ca2+ permeable channels. 总被引:21,自引:8,他引:21
J I Schroeder S Hagiwara 《Proceedings of the National Academy of Sciences of the United States of America》1990,87(23):9305-9309
Many signal-transduction processes in higher plant cells have been suggested to be triggered by signal-induced opening of Ca2+ channels in the plasma membrane. However, direct evidence for activation of plasma-membrane Ca2+ channels by physiological signals in higher plants has not yet been obtained. In this context, several lines of evidence suggest that Ca2+ flux into the cytosol of guard cells is a major factor in the induction of stomatal closing by abscisic acid (ABA). ABA closes stomatal pores, thereby reducing transpirational loss of water by plants under drought conditions. To directly investigate initial events in ABA-induced signal transduction in guard cells, we devised an experimental approach that allows simultaneous photometric measurements of cytosolic Ca2+ and patch-clamp recordings of ion currents across the plasma membrane of single Vicia faba guard cells. Using this approach, we found that the resting cytosolic Ca2+ concentration was 0.19 +/- 0.09 microM (n = 19). In responsive guard cells, external exposure to ABA produced transient repetitive increases in the cytosolic free Ca2+ concentration. These Ca2+ transients were accompanied by concomitantly occurring increases in an inward-directed ion current. Depolarization of the membrane terminated both repetitive elevations in cytosolic Ca2+ and inward-directed ion currents, suggesting that ABA-mediated Ca2+ transients were produced by passive influx of Ca2+ from the extracellular space through Ca2(+)-permeable channels. Detailed voltage-clamp measurements revealed that ABA-activated ion currents could be reversed by depolarizations more positive than -10 mV. Interestingly, reversal potentials of ABA-induced currents show that these currents are not highly Ca2(+)-selective, thereby permitting permeation of both Ca2+ and K+. These results provide direct evidence for ABA activation of Ca2(+)-permeable ion channels in the plasma membrane of guard cells. ABA-activated ion channels allow repetitive elevations in the cytosolic Ca2+ concentration, which, in turn, can modulate cellular responses promoting stomatal closure. 相似文献
993.
Little is known on how longitudinal differences in intestinal iron absorption develop and to what extent distal segments can adapt to a more proximal location after surgical intervention. Therefore, 3 weeks after ileojejunal transposition in rats adaptational changes of intestinal iron transfer were measured together with those of glucose and water transfer, intestinal dry weight and villus surface. In vitro iron transfer (Fisher-Parsons technique) was significantly increased in transposed segments as compared to ileal controls, when related to intestinal length. Jejunal values were not reached, though, which was confirmed by corresponding in vivo results. Increases in intestinal mass which are known to be caused by villus hyperplasia were closely correlated to increases in iron transfer after ileojejunal transposition. Thus, the increased iron transfer might partly be due to an increased number of enterocytes. In addition, transposed enterocytes took up jejunal characteristics regarding the ratio between transferred iron and water quantities which significantly increased the serosal 59Fe concentration as compared to ileal segments. Similar changes were also observed for glucose. Therefore, the adaptation of intestinal 59Fe transfer after ileojejunal transposition seems to be part of a more general adaptation process, essential parts of which are likely to be located in the brush border. 相似文献
994.
Mathys S Schroeder T Ellwart J Koszinowski UH Messerle M Just U 《The Journal of infectious diseases》2003,187(6):988-999
The aim of this study is to analyze the dynamics of the mouse cytomegalovirus (MCMV)-dendritic cell (DC) interaction. Immature and mature DCs derived from the mouse stem cell line factor-dependent cell Paterson mixed potential were infected with a recombinant MCMV expressing green fluorescent protein. Infection of immature DCs resulted in DC activation and virus production, both of which may contribute to viral dissemination. The infection of mature DCs was nonproductive and was restricted to immediate-early and early viral protein expression. During early stages of MCMV infection, mature DCs up-regulated major histocompatibility complex (MHC) and costimulatory molecules and activated autologous, but not allogeneic, naive T cells. At later times of MCMV infection, DCs prevented T cell activation by down-regulation of MHC and costimulatory molecules. Thus, DCs under the influence of MCMV have a physiologic dual role: to initiate and to restrict T cell activation. The lack of immunostimulation in allogeneic settings may explain the increased risk of MCMV morbidity after allogeneic transplantation. 相似文献
995.
Benjamin Darnis Kayvan Mohkam François Cauchy Jean-Baptiste Cazauran Brigitte Bancel Agnès Rode Christian Ducerf Mickaël Lesurtel Jean-Yves Mabrut 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2018,20(11):985-991
Background
Multiple gallbladders (MG) are a rare malformation, with no clear data on its clinical impact, therapeutic indications or risk for malignancy.Methods
A systematic review of all published literature between 1990 and 2017 was performed using the PRISMA guidelines.Results
Data of 181 patients extracted from 153 studies were reviewed. MG were diagnosed during the treatment of a gallstone-related disease in 83% of patients, of which 13% had previous cholecystectomy and had a recurrence of biliary stone disease. The sensitivity of ultrasound scan was 66%, and that of magnetic resonance imaging cholangio-pancreatography, 97%. The cystic duct was common to both gallbladders (type1) in 43% and separated (type 2) in 50% of patients. In the latter case, there was no way to differentiate preoperatively an accessory gallbladder from a Todani II bile duct cyst. Cholecystectomy was performed in 129 patients by laparotomy (43%) or laparoscopy (56%). MG was undiagnosed before surgery in 24% of the patients. The postoperative biliary leakage rate was 0.7%. In two patients, gallbladder cancers were detected.Conclusion
MG are difficult to diagnose and share a common natural history with single gallbladders, without evidence of increased risk for malignancy. Excision of both gallbladders is indicated in symptomatic stone disease. However, prophylactic cholecystectomy must be considered for type 2 MG, since it cannot be preoperatively differentiated from a Todani II bile duct cyst, which is associated with a risk of malignant transformation. 相似文献996.
Change in quality of life among community-dwelling older adults: population-based longitudinal study
Henchoz Yves Abolhassani Nazanin Büla Christophe Guessous Idris Goy René Santos-Eggimann Brigitte 《Quality of life research》2019,28(5):1305-1314
Quality of Life Research - This population-based study aimed to determine 5-year change in multidimensional QoL among community-dwelling older people, and to identify predictors of QoL change among... 相似文献
997.
998.
When children with profound multiple disabilities are hospitalized: A cross‐sectional survey of parental burden of care,quality of life of parents and their hospitalized children,and satisfaction with family‐centered care 下载免费PDF全文
999.