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Ivanova, E. A., M. A. Elmonem, I. Bongaerts, T. Luyten, L. Missiaen, L. P. van den Heuvel, E. N. Levtchenko, and G. Bultynck, "Ca(2+) signalling in human proximal tubular epithelial cells deficient for cystinosin.", Cell calcium, vol. 60, issue 4, pp. 282-7, 2016 Oct. Abstract

Nephropathic cystinosis is an autosomal recessive lysosomal storage disorder caused by loss-of-function mutations in the CTNS gene coding for the lysosomal cystine transporter, cystinosin. Recent studies have demonstrated that, apart from cystine accumulation in the lysosomes, cystinosin-deficient cells, especially renal proximal tubular epithelial cells are characterized by abnormal vesicle trafficking and endocytosis, possible lysosomal dysfunction and perturbed intracellular signalling cascades. It is therefore possible that Ca(2+) signalling is disturbed in cystinosis, as it has been demonstrated for other disorders associated with lysosomal dysfunction, such as Gaucher, Niemann-Pick type C and Alzheimer's diseases. In this study we investigated ATP-induced, IP3-induced and lysosomal Ca(2+) release in human proximal tubular epithelial cells derived from control and cystinotic patients. No major dysregulation of intracellular Ca(2+) dynamics was found, although ATP-induced Ca(2+) release appeared slightly sensitized in cystinotic cells compared to control cells. Hence, these subtle changes in Ca(2+) signals elicited by agonists may contribute to the pathogenesis of the disease.

Ivanova, E. A., F. O. Arcolino, M. A. Elmonem, M. P. Rastaldi, L. Giardino, E. M. Cornelissen, L. P. van den Heuvel, and E. N. Levtchenko, "Cystinosin deficiency causes podocyte damage and loss associated with increased cell motility.", Kidney international, vol. 89, issue 5, pp. 1037-48, 2016 May. Abstract

The involvement of the glomerulus in the pathogenesis of cystinosis, caused by loss-of-function mutations in cystinosin (CTNS, 17p13), is a matter of controversy. Although patients with cystinosis demonstrate glomerular lesions and high-molecular-weight proteinuria starting from an early age, a mouse model of cystinosis develops only signs of proximal tubular dysfunction. Here we studied podocyte damage in patients with cystinosis by analyzing urinary podocyte excretion and by in vitro studies of podocytes deficient in cystinosin. Urine from patients with cystinosis presented a significantly higher amount of podocytes compared with controls. In culture, cystinotic podocytes accumulated cystine compatible with cystinosin deficiency. The expression of podocyte specific genes CD2AP, podocalyxin, and synaptopodin and of the WT1 protein was evident in all cell lines. Conditionally immortalized podocyte lines of 2 patients with different CTNS mutations had altered cytoskeleton, impaired cell adhesion sites, and increased individual cell motility. Moreover, these cells showed enhanced phosphorylation of both Akt1 and Akt2 (isoforms of protein kinase B). Inhibition of Akt by a specific inhibitor (Akti inhibitor 1/2) resulted in normalization of the hypermotile phenotype. Thus, our study extends the list of genetic disorders causing podocyte damage and provides the evidence of altered cell signaling cascades resulting in impaired cell adhesion and enhanced cell motility in cystinosis.

Ivanova, E. A., L. P. van den Heuvel, M. A. Elmonem, H. De Smedt, L. Missiaen, A. Pastore, D. Mekahli, G. Bultynck, and E. N. Levtchenko, "Altered mTOR signalling in nephropathic cystinosis.", Journal of inherited metabolic disease, vol. 39, issue 3, pp. 457-64, 2016 May. Abstract

Lysosomes play a central role in regulating autophagy via activation of mammalian target of rapamycin complex 1 (mTORC1). We examined mTORC1 signalling in the lysosomal storage disease nephropathic cystinosis (MIM 219800), in which accumulation of autophagy markers has been previously demonstrated. Cystinosis is caused by mutations in the lysosomal cystine transporter cystinosin and initially affects kidney proximal tubules causing renal Fanconi syndrome, followed by a gradual development of end-stage renal disease and extrarenal complications. Using proximal tubular kidney cells obtained from healthy donors and from cystinotic patients, we demonstrate that cystinosin deficiency is associated with a perturbed mTORC1 signalling, delayed reactivation of mTORC1 after starvation and abnormal lysosomal retention of mTOR during starvation. These effects could not be reversed by treatment with cystine-depleting drug cysteamine. Altered mTORC1 signalling can contribute to the development of proximal tubular dysfunction in cystinosis and points to new possibilities in therapeutic intervention through modulation of mTORC-dependent signalling cascades.

Iwama, H., S. Mehanna, M. Imasaka, S. Hashidume, H. Nishiura, K. -ichi Yamamura, C. Suzuki, Y. Uchiyama, E. Hatano, and M. Ohmuraya, "Cathepsin B and D deficiency in the mouse pancreas induces impaired autophagy and chronic pancreatitis", Scientific Reports, vol. 11, issue 1, pp. 6596, 2021.
IY, E., T. AF, K. HA, and E. HH, "Screening of the Potential antihypercholestermic activity of some Egyptain Herbs", Inter. J. of Pharmacotherapy, vol. 4, issue 2, pp. 74-79, 2014.
Izak, A. M., L. Werner, D. J. Apple, T. A. Macky, R. H. Trivedi, and S. K. Pandey, "Loop memory of haptic materials in posterior chamber intraocular lenses.", Journal of cataract and refractive surgery, vol. 28, issue 7, pp. 1229-35, 2002 Jul. Abstract

PURPOSE: To compare the shape recovery ratios after compression of haptic materials used in the manufacture of intraocular lenses (IOLs).

SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS: The loop memory of 40 silicone-optic posterior chamber IOLs was studied. All the IOLs had modified-C haptics made of poly(methyl methacrylate) (PMMA; n = 10), polyimide (n = 10), polyvinylidene fluoride (PVDF; n = 10), and polypropylene (PP; n = 10). After the overall diameter of each lens was measured (day 0), the lenses were inserted into plastic wells (9.5 mm in diameter) and immersed in water (37 degrees C) for 1 month. They were then placed on an open plate and allowed to reexpand for 2 months. Overall diameter measurements were performed within 5 minutes of the IOLs' removal from the wells and at subsequent time points (days 14, 28, 30, 60, 74, 88, and 95).

RESULTS: The loop memory of each lens was expressed as the difference between the initial overall diameter measurement (pretest) and the measurement at each time point; the lower the value, the higher the memory. The overall difference among the 4 groups was statistically significant at each time point (P < or = .001). From days 30 to 95, silicone-PMMA, silicone-elastimide, and silicone-PVDF IOLs had similar loop memory mean values, which were significantly lower than the mean value of silicone-PP IOLs (P <.05). The latter design tended to be deformed after removal from the wells, with increased optic-haptic angulation.

CONCLUSION: Studying the loop memory of haptic materials (PMMA, polyimide, PVDF, and PP) used in the manufacture of posterior chamber IOLs can help surgeons choose an appropriate IOL for each patient.

Izak, A. M., D. J. Apple, L. Werner, R. H. Trivedi, S. K. Pandey, T. A. Macky, J. M. Schmidbauer, and P. Marsh, "Bipseudophakia: clinicopathological correlation of a dropped lens.", Journal of cataract and refractive surgery, vol. 28, issue 5, pp. 874-82, 2002 May. Abstract

PURPOSE: To examine postmortem human globes containing an anterior chamber and a posterior chamber intraocular lens (IOL).

SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Charleston, South Carolina, USA.

METHODS: The globes were sectioned at the equator, and the anterior and posterior segments were macroscopically examined. Gross photographs were taken using the Miyake-Apple posterior photographic technique. Histological sections were cut and stained with hematoxylin and eosin, periodic acid-Schiff, and Masson's trichrome.

RESULTS: Histopathological findings included a large Soemmering's ring, a tear in the posterior capsule, 1 haptic of the anterior chamber IOL displaced into the iridectomy, thin and atrophic corneal epithelium, separation of Bowman's layer and stroma by fibrovascular tissue, and atrophy of the retinal ganglion cell layer and nerve fiber layer.

CONCLUSION: In cases in which secondary IOL implantation is indicated, removing the dislocated IOL appears to be a reasonable choice.

Izak, A. M., L. Werner, S. K. Pandey, T. A. Macky, R. H. Trivedi, and D. J. Apple, "Calcification on the surface of the Bausch & Lomb Hydroview intraocular lens.", International ophthalmology clinics, vol. 41, issue 3, pp. 63-77, 2001 Summer.
Izetbegovic, A., هروبي إلى الحرية, , Cairo, Madarat for Research Publishing, 2015.