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Gasingirwa M.-C.,University of Namur | Gasingirwa M.-C.,Nur University | Thirion J.,University of Namur | Mertens-Strijthagen J.,University of Namur | And 4 more authors.
Biochemical Journal | Year: 2010

It has been suggested that intracellular Hyal-1 (hyaluronidase-1), which is considered a lysosomal enzyme, originates via endocytosis of the serum enzyme. To test this proposal we have investigated the uptake and intracellular distribution of rhHyal-1 (recombinant human Hyal-1) by mouse liver, making use of centrifugation methods. Experiments were performed on wild-type mice injected with 125I-labelled rhHyal-1 and on Hyal-1-/- mice injected with the unlabelled enzyme, which were killed at various times after injection. Activity of the unlabelled enzyme was determined by zymography. Intracellular distribution of Hyal-1 was investigated by differential and isopycnic centrifugation. The results of the study indicated that rhHyal-1 is endocytosed by the liver, mainly by sinusoidal cells, and follows the intracellular pathway described for many endocytosed proteins that are eventually located in lysosomes. However, Hyal-1 endocytosis has some particular features. First, endocytosed rhHyal-1 is quickly degraded. Secondly, its distribution, as analysed by differential centrifugation, differs from the distribution of β-galactosidase, taken as the reference lysosomal enzyme. Further analysis by isopycnic centrifugation in a sucrose gradient shows endocytosed rhHyal-1 behaves like β-galactosidase shortly after injection. However the Hyal-1 distribution is markedly less affected than β-galactosidase, following a prior injection of Triton WR-1339, which is a specific density perturbant of lysosomes. The behaviour in centrifugation of endogenous liver Hyal-1, identified by hyaluronan zymography, exhibits some similarity with the behaviour of the endocytosed enzyme, suggesting that it could originate from endocytosis of the serum enzyme. Overall, these results can be explained by supposing that active endocytosed Hyal-1 is mainly present in early lysosomes. Although its degradation half-time is short, Hyal-1 could exert its activity due to a constant supply of active molecules from the blood. © The Authors. Source

Gharahi Ghehi N.,Ghent University | Werner C.,Biodiversity and Climate Research Center F | Cizungu Ntaboba L.,Ghent University | Mbonigaba Muhinda J.J.,Nur University | And 4 more authors.
Biogeosciences | Year: 2012

Globally, tropical forest soils represent the second largest source of N 2O and NO. However, there is still considerable uncertainty on the spatial variability and soil properties controlling N trace gas emission. Therefore, we carried out an incubation experiment with soils from 31 locations in the Nyungwe tropical mountain forest in southwestern Rwanda. All soils were incubated at three different moisture levels (50, 70 and 90 % water filled pore space (WFPS)) at 17 °C. Nitrous oxide emission varied between 4.5 and 400 μg N m -2 hg -1, while NO emission varied from 6.6 to 265μg N mg -2 h -1. Mean N2O emission at different moisture levels was 46.5 ± 11.1 (50 %WFPS), 71.7±11.5 (70 %WFPS) and 98.8±16.4 (90 %WFPS) μg N mg -2 h -1, while mean NO emission was 69.3±9.3 (50 %WFPS), 47.1±5.8 (70 %WFPS) and 36.1±4.2 (90 %WFPS) μg N m -2 h -1. The latter suggests that climate (i.e. dry vs. wet season) controls N 2O and NO emissions. Positive correlations with soil carbon and nitrogen indicate a biological control over N 2O and NO production. But interestingly N 2O and NO emissions also showed a positive correlation with free iron and a negative correlation with soil pH (only N 2O). The latter suggest that chemo-denitrification might, at least for N 2O, be an important production pathway. In conclusion improved understanding and process based modeling of N trace gas emission from tropical forests will benefit from spatially explicit trace gas emission estimates linked to basic soil property data and differentiating between biological and chemical pathways for N trace gas formation. © 2012 Author(s). CC Attribution 3.0 License. Source

Ahmad A.H.,Shaukat Khanum Memorial Cancer Hospital | Saeed M.A.,Nur University
Journal of the Pakistan Medical Association | Year: 2016

Idiopathic Retroperitoneal fibrosis is a rare clinical condition recently identified as an autoimmune process related to Immunoglobulin G4 (IgG4) deposition. Herein we report a case of a 46 year old male presenting with 4 months history of backache, fever, flank pain and leg swelling for 2 weeks. Investigations revealed acute kidney injury diagnosed as a result of bilateral ureteric obstruction. This was later confirmed to be retroperitoneal fibrosis on CT scan and biopsy. Histopathology was consistent with IgG4 related disease. Treatment with immunosuppressive agents showed reduction in the fibrosis and normalization of the kidney functions. We discuss the IgG4 related retroperitoneal fibrosis in detail along with its varied presentations. © 2016, Pakistan Medical Association. All rights reserved. Source

Westinga E.,University of Twente | Mukashema A.,Nur University | Van Gils H.,University of Twente
Forestry | Year: 2013

Comparisons of national forest inventories have been undertaken at coarse resolutions in Europe, but not at fine resolutions and not in Africa. This study compares the consecutive (1990, 2000, 2005, 2010), census-based Food and Agriculture Organisation Forest Resources Assessments (FRAs) of Rwanda with contemporary fine-resolution, image-based inventories. Natural forest and forest plantation were extracted from 1985 to 1989 topographic maps, Africover 2002 and Centre of Geographic Information Systems and Remote Sensing (CGIS) 2007. The natural forest area estimates over the years obtained by image-based inventories are fairly constant from the earliest inventory (topo-1988; 140 000 ha), through Africover (135 500 ha) to CGIS (125 300 ha). FRA 2000 (46 000 ha), 2005 (61 000 ha) and 2010 (62 000 ha) estimates are lower, whereas FRA 1990 (164 000 ha) reported the largest extent of natural forest. The extent of forest plantations is at its lowest level in Africover (68 600 ha). However, CGIS (114 000 ha) detected a larger area of forest plantation, more similar to the levels reported in the FRA 1990 (125 000 ha) and topo-1988 (125 200 ha). The three recent FRAs (2000: 261 000 ha; 2005: 419 000 ha; 2010: 373 000 ha) report larger plantation extents. For the image-based inventories, we could estimate the uncertainty in each step of the inventory, while for the census-based cases, the required transparency is lacking. Uncertainty may be caused by definition of forest, forest versus forestland, image classification errors, image resolution, forest fragmentation or time-lags between imagery and reporting. In our pairwise comparison of the census and contemporary image-based inventories, all uncertainties are added. The FRA 2000 (307 000 ha) reports a larger total forest area than Africover (204 100 ha). The uncertainties of Africover add up to maximally 64 100 ha, which may explain part of the difference. The uncertainties in the CGIS inventory add up to nearly 15 000 ha and cannot explain the difference between FRA 2005 (480 000 ha) and GCGIS 2007 (239 300 ha).We conclude that FRAs starting in 2000 over-report the forest plantation area and under-estimate the extent of natural forest. Finally, we suggest technical and organizational improvements for national forest inventories. © Institute of Chartered Foresters, 2013. All rights reserved. Source

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