Hepatic periportal fibrosis (PPF), associated with portal hypertension, is a major pathological c... more Hepatic periportal fibrosis (PPF), associated with portal hypertension, is a major pathological consequence of infections with Schistosoma mansoni and Schistosoma japonicum. Indeed, affected subjects may die from portal hypertension. Previous studies have indicated that tumor necrosis factor alpha (TNF-␣) may aggravate fibrosis. We therefore investigated whether PPF was associated with certain polymorphisms of the TNF-␣ gene. Four polymorphisms (TNF-␣ ؊376 G/A, ؊308 G/A, ؊238 G/A, and ؉488 G/A) were investigated in two Sudanese populations living in an area in which S. mansoni is endemic. These polymorphisms were analyzed for 105 Sudanese subjects with various grades of PPF, from mild to advanced; all subjects were from two neighboring villages (Taweela and Umzukra). They were then analyzed for 70 subjects with advanced liver disease and for 345 matched controls from the Gezira region. We found no evidence of associations between these four polymorphisms and PPF in both of these studies. Thus, these four polymorphisms, two of which (TNF-␣ ؊376 and ؊308) were found to increase TNF-␣ gene transcription, are unlikely to have a major effect on PPF progression in these populations. However, this result does not exclude the possibility that these polymorphisms have a minor effect on PPF development.
Retinal degeneration is the leading cause of untreatable blindness in the developed world. Cell t... more Retinal degeneration is the leading cause of untreatable blindness in the developed world. Cell transplantation strategies provide a novel therapeutic approach to repair the retina and restore sight. Previously, we have shown that photoreceptor precursor cells can integrate and form functional photoreceptors after transplantation into the subretinal space of the adult mouse. In a clinical setting, however, it is likely that far greater numbers of integrated photoreceptors would be required to restore visual function. We therefore sought to assess whether the outer limiting membrane (OLM), a natural barrier between the subretinal space and the outer nuclear layer (ONL), could be reversibly disrupted and if disruption of this barrier could lead to enhanced numbers of transplanted photoreceptors integrating into the ONL. Transient chemical disruption of the OLM was induced in adult mice using the glial toxin, dl-alpha-aminoadipic acid (AAA). Dissociated early post-natal neural retinal cells were transplanted via subretinal injection at various time-points after AAA administration. At 3 weeks post-injection, the number of integrated, differentiated photoreceptor cells was assessed and compared with those found in the PBS-treated contralateral eye. We demonstrate for the first time that the OLM can be reversibly disrupted in adult mice, using a specific dose of AAA administered by intravitreal injection. In this model, OLM disruption is maximal at 72 h, and recovers by 2 weeks. When combined with cell transplantation, disruption of the OLM leads to a significant increase in the number of photoreceptors integrated within the ONL compared with PBS-treated controls. This effect was only seen in animals in which AAA had been administered 72 h prior to transplantation, i.e. when precursor cells were delivered into the subretinal space at a time coincident with maximal OLM disruption. These findings suggest that the OLM presents a physical barrier to photoreceptor integration following transplantation into the subretinal space in the adult mouse. Reversible disruption of the OLM may provide a strategy for increasing cell integration in future therapeutic applications.
Many advantages are attained by integrating 3G and WLAN systems to form a 3G-WLAN interworking ar... more Many advantages are attained by integrating 3G and WLAN systems to form a 3G-WLAN interworking architecture. However, securing the architecture is a great challenge because of the number of vulnerabilities introduced. EAP-AKA is the authentication solution adopted by the 3GPP to secure accesses to 3G-WLAN architectures. Two types of EAP-AKA authentication are available, full authentication and fast re-authentication. This paper presents a localized fast re-authentication protocol to substitute the standard fast re-authentication protocol. The proposed protocol achieves faster re- authentication by locally performing the authentication procedure. A new keying framework is introduced to minimize authentication delays during re-authentication and handover operations.
European Journal of Vascular and Endovascular Surgery, 1997
Objectives: To compare the costs of endovascular aneurysm treatment versus open surgery during th... more Objectives: To compare the costs of endovascular aneurysm treatment versus open surgery during the perioperative period. Methods: Retrospective analysis of a consecutive series of 44 patients undergoing infrarenal abdominal aneurysm repair from February 1995 to March 1996 at a university teaching hospital. Results: No endovascular procedure was converted to open repair. Operative time was shorter for endovascular treatment (207.6 min vs. 229.1 rain, n.s.), as well as postoperative intensive care unit stay (ICU, 22.7 h vs. 55.0 h, p = 0.017) and the postoperative recovery period (5.6 days vs. 13.3 days, p<O.O01). Open surgery generated significantly more costs (25 374.07 ECU vs. 22 268.78 ECU, p<O.O01), despite evaluation and a more expensive endovascular procedure (10 699.48 ECU vs. 4032.01 ECU, p<O.O01). During the study, costs for open surgery exceeded the cost for endovascular treatment by 13.95%. Conclusions: Endovascular aneurysm treatment is cost effective and less expensive than open surgery. The main reason for cost saving is faster patient recovery after surgery, associated with a shorter LOS in the patients treated with endovascular procedure.
Background and Purpose-Both environmental and genetic factors contribute to the formation, growth... more Background and Purpose-Both environmental and genetic factors contribute to the formation, growth, and rupture of intracranial aneurysms (IAs). To search for IA susceptibility genes, we took an outlier approach, using parametric genome-wide linkage analysis in extended IA kindreds in which IA is inherited as a simple Mendelian trait. We hereby present the molecular genetic analysis of 2 such families. Methods-For genome-wide linkage analysis, we used a 2-stage approach. First, using gene chips in affected-only analysis, we identified genomic regions that provide maximum theoretical logarithm of odds (lod) scores. Next, to confirm or exclude these candidate loci, we genotyped all available family members, both affected and unaffected, using polymorphic microsatellite markers located within these regions. Results-We obtained significant lod scores of 4.3 and 3.00 for linkage to chromosomes 11q24-25 and 14q23-31, respectively. Conclusions-Molecular genetic analysis of 2 large IA kindreds confirms linkage to chromosome 11q and 14q, which were suggested to contain IA susceptibility genes in a previous study of Japanese sib pairs. Independent identification of these 2 loci strongly suggests that IA susceptibility genes lie within these regions. While demonstrating the genetic heterogeneity of IA, these results are also an important step toward cloning IA genes and ultimately understanding its pathophysiology.
Lesion characteristics and patient factors can predict long-term patency after intervention. This... more Lesion characteristics and patient factors can predict long-term patency after intervention. This comprehensive evaluation of over 1800 lesions provides a basis for development of a LSS to standardize lesion classification and allow for comparisons between centers based on lesion location, combinations of lesions, patient co-morbidities, and treatment modalities.
Authorization, authentication, and accounting schemes for WiMAX (Worldwide Interoperability for M... more Authorization, authentication, and accounting schemes for WiMAX (Worldwide Interoperability for Microwave Access) are the focus of this paper. WiMAX works as a wireless metropolitan area network (MAN) technology, based on IEEE 802.16 specifications, which was designed to provide high-throughput wireless broadband connections (up to 70 Mbps for fixed scheme and up to 15 Mbps for mobile scheme) over long distances (up to 30 miles) , which is described as a "framework for the evolution of wireless broadband". The main focus of the authentication and authorization is based on the privacy key management $extensible authentication protocol for pairwise key manegement "EAP-PKM" and the accounting issue
Over the past several years, advances in our understanding of the pathogenesis of acute kidney in... more Over the past several years, advances in our understanding of the pathogenesis of acute kidney injury (AKI) have demonstrated the role of oxidant stress and reactive oxygen metabolites (ROM) in the development of AKI in a variety of clinical settings. This review serves to define the pathways that lead to the generation of ROM following a variety of insults, as well as to review the current literature concerning the role of antioxidant therapy in the prevention and treatment of AKI in several clinical settings. Investigators have explored the potential therapeutic role of anti-oxidants in both experimental animal models and human studies of AKI in several clinical settings, including cardiac and aortic occlusive surgeries, sepsis, drug nephrotoxicity (cisplatin and gentamicin), as well as rhabdomyolysis. While the experimental animal studies have generally been more successful, taken together this literature supports the hypothesis that oxidant stress-induced production of ROM plays a major role in the pathogenesis of many forms of AKI, and continues to suggest the potential utility of antioxidant therapy in human AKI. Ongoing trials in concert with improved diagnostic techniques will hopefully lead to improved outcomes in the setting of AKI through the prophylactic or early therapeutic use of antioxidant therapy.
Endocytosis, subsequent protein sorting into multivesicular bodies (MVBs), and eventual degradati... more Endocytosis, subsequent protein sorting into multivesicular bodies (MVBs), and eventual degradation in lysosomes compose an important mechanism for controlling protein expression on the plasma membrane. The lysosomal trafficking regulator interacting protein-5 (LIP5) is part of the complex protein machinery involved in MVB biosynthesis. LIP5 interacts with other players of the ESCRT machinery as well as with two known cargo proteins, AQP2 and EGFR, whose degradation is affected upon reduction of LIP5 expression. To investigate the expression and localization pattern of LIP5, we studied LIP5 protein expression in a mouse tissue panel and subjected various rodent and human tissues to immunohistochemistry. Immunoblotting revealed that, except for jejunum, LIP5 is expressed as a 42 kDa protein in all mouse tissues tested. Alternatively-spliced gene products could not be detected. Immunohistochemical studies revealed that in tissues positive for LIP5, LIP5 is detected in virtually all epithelial cells of the examined rodent and human tissues. The observed LIP5 expression in epithelial tissues suggests that LIP5 is of particular importance in the MVB sorting and degradation of proteins expressed in polarized cells.
Hepatic periportal fibrosis (PPF), associated with portal hypertension, is a major pathological c... more Hepatic periportal fibrosis (PPF), associated with portal hypertension, is a major pathological consequence of infections with Schistosoma mansoni and Schistosoma japonicum. Indeed, affected subjects may die from portal hypertension. Previous studies have indicated that tumor necrosis factor alpha (TNF-␣) may aggravate fibrosis. We therefore investigated whether PPF was associated with certain polymorphisms of the TNF-␣ gene. Four polymorphisms (TNF-␣ ؊376 G/A, ؊308 G/A, ؊238 G/A, and ؉488 G/A) were investigated in two Sudanese populations living in an area in which S. mansoni is endemic. These polymorphisms were analyzed for 105 Sudanese subjects with various grades of PPF, from mild to advanced; all subjects were from two neighboring villages (Taweela and Umzukra). They were then analyzed for 70 subjects with advanced liver disease and for 345 matched controls from the Gezira region. We found no evidence of associations between these four polymorphisms and PPF in both of these studies. Thus, these four polymorphisms, two of which (TNF-␣ ؊376 and ؊308) were found to increase TNF-␣ gene transcription, are unlikely to have a major effect on PPF progression in these populations. However, this result does not exclude the possibility that these polymorphisms have a minor effect on PPF development.
Retinal degeneration is the leading cause of untreatable blindness in the developed world. Cell t... more Retinal degeneration is the leading cause of untreatable blindness in the developed world. Cell transplantation strategies provide a novel therapeutic approach to repair the retina and restore sight. Previously, we have shown that photoreceptor precursor cells can integrate and form functional photoreceptors after transplantation into the subretinal space of the adult mouse. In a clinical setting, however, it is likely that far greater numbers of integrated photoreceptors would be required to restore visual function. We therefore sought to assess whether the outer limiting membrane (OLM), a natural barrier between the subretinal space and the outer nuclear layer (ONL), could be reversibly disrupted and if disruption of this barrier could lead to enhanced numbers of transplanted photoreceptors integrating into the ONL. Transient chemical disruption of the OLM was induced in adult mice using the glial toxin, dl-alpha-aminoadipic acid (AAA). Dissociated early post-natal neural retinal cells were transplanted via subretinal injection at various time-points after AAA administration. At 3 weeks post-injection, the number of integrated, differentiated photoreceptor cells was assessed and compared with those found in the PBS-treated contralateral eye. We demonstrate for the first time that the OLM can be reversibly disrupted in adult mice, using a specific dose of AAA administered by intravitreal injection. In this model, OLM disruption is maximal at 72 h, and recovers by 2 weeks. When combined with cell transplantation, disruption of the OLM leads to a significant increase in the number of photoreceptors integrated within the ONL compared with PBS-treated controls. This effect was only seen in animals in which AAA had been administered 72 h prior to transplantation, i.e. when precursor cells were delivered into the subretinal space at a time coincident with maximal OLM disruption. These findings suggest that the OLM presents a physical barrier to photoreceptor integration following transplantation into the subretinal space in the adult mouse. Reversible disruption of the OLM may provide a strategy for increasing cell integration in future therapeutic applications.
Many advantages are attained by integrating 3G and WLAN systems to form a 3G-WLAN interworking ar... more Many advantages are attained by integrating 3G and WLAN systems to form a 3G-WLAN interworking architecture. However, securing the architecture is a great challenge because of the number of vulnerabilities introduced. EAP-AKA is the authentication solution adopted by the 3GPP to secure accesses to 3G-WLAN architectures. Two types of EAP-AKA authentication are available, full authentication and fast re-authentication. This paper presents a localized fast re-authentication protocol to substitute the standard fast re-authentication protocol. The proposed protocol achieves faster re- authentication by locally performing the authentication procedure. A new keying framework is introduced to minimize authentication delays during re-authentication and handover operations.
European Journal of Vascular and Endovascular Surgery, 1997
Objectives: To compare the costs of endovascular aneurysm treatment versus open surgery during th... more Objectives: To compare the costs of endovascular aneurysm treatment versus open surgery during the perioperative period. Methods: Retrospective analysis of a consecutive series of 44 patients undergoing infrarenal abdominal aneurysm repair from February 1995 to March 1996 at a university teaching hospital. Results: No endovascular procedure was converted to open repair. Operative time was shorter for endovascular treatment (207.6 min vs. 229.1 rain, n.s.), as well as postoperative intensive care unit stay (ICU, 22.7 h vs. 55.0 h, p = 0.017) and the postoperative recovery period (5.6 days vs. 13.3 days, p<O.O01). Open surgery generated significantly more costs (25 374.07 ECU vs. 22 268.78 ECU, p<O.O01), despite evaluation and a more expensive endovascular procedure (10 699.48 ECU vs. 4032.01 ECU, p<O.O01). During the study, costs for open surgery exceeded the cost for endovascular treatment by 13.95%. Conclusions: Endovascular aneurysm treatment is cost effective and less expensive than open surgery. The main reason for cost saving is faster patient recovery after surgery, associated with a shorter LOS in the patients treated with endovascular procedure.
Background and Purpose-Both environmental and genetic factors contribute to the formation, growth... more Background and Purpose-Both environmental and genetic factors contribute to the formation, growth, and rupture of intracranial aneurysms (IAs). To search for IA susceptibility genes, we took an outlier approach, using parametric genome-wide linkage analysis in extended IA kindreds in which IA is inherited as a simple Mendelian trait. We hereby present the molecular genetic analysis of 2 such families. Methods-For genome-wide linkage analysis, we used a 2-stage approach. First, using gene chips in affected-only analysis, we identified genomic regions that provide maximum theoretical logarithm of odds (lod) scores. Next, to confirm or exclude these candidate loci, we genotyped all available family members, both affected and unaffected, using polymorphic microsatellite markers located within these regions. Results-We obtained significant lod scores of 4.3 and 3.00 for linkage to chromosomes 11q24-25 and 14q23-31, respectively. Conclusions-Molecular genetic analysis of 2 large IA kindreds confirms linkage to chromosome 11q and 14q, which were suggested to contain IA susceptibility genes in a previous study of Japanese sib pairs. Independent identification of these 2 loci strongly suggests that IA susceptibility genes lie within these regions. While demonstrating the genetic heterogeneity of IA, these results are also an important step toward cloning IA genes and ultimately understanding its pathophysiology.
Lesion characteristics and patient factors can predict long-term patency after intervention. This... more Lesion characteristics and patient factors can predict long-term patency after intervention. This comprehensive evaluation of over 1800 lesions provides a basis for development of a LSS to standardize lesion classification and allow for comparisons between centers based on lesion location, combinations of lesions, patient co-morbidities, and treatment modalities.
Authorization, authentication, and accounting schemes for WiMAX (Worldwide Interoperability for M... more Authorization, authentication, and accounting schemes for WiMAX (Worldwide Interoperability for Microwave Access) are the focus of this paper. WiMAX works as a wireless metropolitan area network (MAN) technology, based on IEEE 802.16 specifications, which was designed to provide high-throughput wireless broadband connections (up to 70 Mbps for fixed scheme and up to 15 Mbps for mobile scheme) over long distances (up to 30 miles) , which is described as a "framework for the evolution of wireless broadband". The main focus of the authentication and authorization is based on the privacy key management $extensible authentication protocol for pairwise key manegement "EAP-PKM" and the accounting issue
Over the past several years, advances in our understanding of the pathogenesis of acute kidney in... more Over the past several years, advances in our understanding of the pathogenesis of acute kidney injury (AKI) have demonstrated the role of oxidant stress and reactive oxygen metabolites (ROM) in the development of AKI in a variety of clinical settings. This review serves to define the pathways that lead to the generation of ROM following a variety of insults, as well as to review the current literature concerning the role of antioxidant therapy in the prevention and treatment of AKI in several clinical settings. Investigators have explored the potential therapeutic role of anti-oxidants in both experimental animal models and human studies of AKI in several clinical settings, including cardiac and aortic occlusive surgeries, sepsis, drug nephrotoxicity (cisplatin and gentamicin), as well as rhabdomyolysis. While the experimental animal studies have generally been more successful, taken together this literature supports the hypothesis that oxidant stress-induced production of ROM plays a major role in the pathogenesis of many forms of AKI, and continues to suggest the potential utility of antioxidant therapy in human AKI. Ongoing trials in concert with improved diagnostic techniques will hopefully lead to improved outcomes in the setting of AKI through the prophylactic or early therapeutic use of antioxidant therapy.
Endocytosis, subsequent protein sorting into multivesicular bodies (MVBs), and eventual degradati... more Endocytosis, subsequent protein sorting into multivesicular bodies (MVBs), and eventual degradation in lysosomes compose an important mechanism for controlling protein expression on the plasma membrane. The lysosomal trafficking regulator interacting protein-5 (LIP5) is part of the complex protein machinery involved in MVB biosynthesis. LIP5 interacts with other players of the ESCRT machinery as well as with two known cargo proteins, AQP2 and EGFR, whose degradation is affected upon reduction of LIP5 expression. To investigate the expression and localization pattern of LIP5, we studied LIP5 protein expression in a mouse tissue panel and subjected various rodent and human tissues to immunohistochemistry. Immunoblotting revealed that, except for jejunum, LIP5 is expressed as a 42 kDa protein in all mouse tissues tested. Alternatively-spliced gene products could not be detected. Immunohistochemical studies revealed that in tissues positive for LIP5, LIP5 is detected in virtually all epithelial cells of the examined rodent and human tissues. The observed LIP5 expression in epithelial tissues suggests that LIP5 is of particular importance in the MVB sorting and degradation of proteins expressed in polarized cells.
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