HASSAN AHMAD - Academia.edu (original) (raw)

Papers by HASSAN AHMAD

Biochimica et Biophysica Acta (BBA) - General Subjects, 1992

Sex-related differences in the expression of glutathione S-transferase (GST) isozymes of mouse li... more Sex-related differences in the expression of glutathione S-transferase (GST) isozymes of mouse liver have been described. There were no apparent qualitative differences in the isoelectric focusing profiles of the GST isozymes from male and female mouse liver. Both male and female mice have at least four GST isozymes in their liver with pI values of 9.8, 8.7, 6.4 and 5.7. Kinetic, immunological, and structural properties including the N-terminal region amino acid sequences of these isozymes have been determined and they have been classified into alpha, mu, and pi classes. The most cationic isozyme (pI 9.8) belongs to the alpha class and is comparatively more abundant in female liver. The isozyme having pI 8.7 belongs to the pi class and is more abundant in male liver. The mu class GST pI 6.4 as well as the isozyme having pI 5.7 which corresponded to the a class isozyme GST 8-8 of rat liver were more abundant (about 1.5-fold) in male mouse liver as compared to the female. Interestingly, present studies reveal sex-related differences in the heat stabilities of the alpha and pi class GSTs of mouse liver. The alpha class GST pI (9.8) isolated from female mouse liver was more thermostable as compared to the corresponding enzyme from male mouse liver. On the contrary, the pi class GST (pI 8.7) from male mouse was more thermostable as compared to the corresponding enzyme from the female mouse.

Experimental Eye Research, 1992

Studies were undertaken to investigate the effect of t-butylated hydroxytoluene (BHT) on reduced ... more Studies were undertaken to investigate the effect of t-butylated hydroxytoluene (BHT) on reduced glutathione (GSH) levels and related enzymes in rat ocular tissues. GSH levels were significantly enhanced when 1 PM BHT was included in the medium of rat lens cultures. BHT had a dose-dependent effect on GSH levels of lenses in cultures. Inclusion of 10 ,uM BHT in the culture medium resulted in a twofold increase in GSH levels of the lens within 24 hr. Increased y-glutamylcysteine synthetase activity concomitant with the increased amount of [35S]methionine incorporation in GSH strongly suggested that BHT caused enhanced levels of GSH in lenses by increasing de novo biosynthesis. A significant increase was also observed in glutathione S-transferase (GST) levels of lenses in culture containing BHT in the medium. Present studies also demonstrated that rat lens expresses only the p and 77 class GST isoenzymes and both these classes of isoenzymes were elevated by BHT. Oral administration of BHT to rats also resulted in enhanced in vivo levels of GSH in lens, retina and cornea. In addition, a significant in vivo increase in the levels of GST. GSH-peroxidase, GSH-reductase, y-glutamylcysteine synthetase, and glucose 6-phosphate dehydrogenase was observed in the lens, retina, and cornea of BHT-fed rats.

Osgoode Hall Law Journal, 2011

Economic Change and Restructuring, 2015

The study examines the twin de…cits hypothesis in a sample of twelve African countries for the pe... more The study examines the twin de…cits hypothesis in a sample of twelve African countries for the period between 1980 and 2009. These countries have experienced both the current account and the …scal de…cits, among others, that prompted an introduction of structural reforms. The paper explores long-run relationship between the series and their short-run dynamics within the context of endogenously determined structural breaks. The identi…ed dates are generally associated with external factors that include commodity price boom and burst cycles that the countries heavily depend on. The estimated results for eight of the countries indicate that there is a positive relationship between the current account and …scal de…cits and therefore, support the twin de…cits hypothesis. Results for the remaining four countries of Ethiopia, Kenya, South Africa and Uganda, on the other hand, show that the relationship between the two is negative. y We are very grateful to the editor and acknowledge the anonymous reviewers'useful and constructive comments.

Biochimica et Biophysica Acta (BBA) - General Subjects, 1992

Sex-related differences in the expression of glutathione S-transferase (GST) isozymes of mouse li... more Sex-related differences in the expression of glutathione S-transferase (GST) isozymes of mouse liver have been described. There were no apparent qualitative differences in the isoelectric focusing profiles of the GST isozymes from male and female mouse liver. Both male and female mice have at least four GST isozymes in their liver with pI values of 9.8, 8.7, 6.4 and 5.7. Kinetic, immunological, and structural properties including the N-terminal region amino acid sequences of these isozymes have been determined and they have been classified into alpha, mu, and pi classes. The most cationic isozyme (pI 9.8) belongs to the alpha class and is comparatively more abundant in female liver. The isozyme having pI 8.7 belongs to the pi class and is more abundant in male liver. The mu class GST pI 6.4 as well as the isozyme having pI 5.7 which corresponded to the a class isozyme GST 8-8 of rat liver were more abundant (about 1.5-fold) in male mouse liver as compared to the female. Interestingly, present studies reveal sex-related differences in the heat stabilities of the alpha and pi class GSTs of mouse liver. The alpha class GST pI (9.8) isolated from female mouse liver was more thermostable as compared to the corresponding enzyme from male mouse liver. On the contrary, the pi class GST (pI 8.7) from male mouse was more thermostable as compared to the corresponding enzyme from the female mouse.

Experimental Eye Research, 1992

Studies were undertaken to investigate the effect of t-butylated hydroxytoluene (BHT) on reduced ... more Studies were undertaken to investigate the effect of t-butylated hydroxytoluene (BHT) on reduced glutathione (GSH) levels and related enzymes in rat ocular tissues. GSH levels were significantly enhanced when 1 PM BHT was included in the medium of rat lens cultures. BHT had a dose-dependent effect on GSH levels of lenses in cultures. Inclusion of 10 ,uM BHT in the culture medium resulted in a twofold increase in GSH levels of the lens within 24 hr. Increased y-glutamylcysteine synthetase activity concomitant with the increased amount of [35S]methionine incorporation in GSH strongly suggested that BHT caused enhanced levels of GSH in lenses by increasing de novo biosynthesis. A significant increase was also observed in glutathione S-transferase (GST) levels of lenses in culture containing BHT in the medium. Present studies also demonstrated that rat lens expresses only the p and 77 class GST isoenzymes and both these classes of isoenzymes were elevated by BHT. Oral administration of BHT to rats also resulted in enhanced in vivo levels of GSH in lens, retina and cornea. In addition, a significant in vivo increase in the levels of GST. GSH-peroxidase, GSH-reductase, y-glutamylcysteine synthetase, and glucose 6-phosphate dehydrogenase was observed in the lens, retina, and cornea of BHT-fed rats.

Osgoode Hall Law Journal, 2011

Economic Change and Restructuring, 2015

The study examines the twin de…cits hypothesis in a sample of twelve African countries for the pe... more The study examines the twin de…cits hypothesis in a sample of twelve African countries for the period between 1980 and 2009. These countries have experienced both the current account and the …scal de…cits, among others, that prompted an introduction of structural reforms. The paper explores long-run relationship between the series and their short-run dynamics within the context of endogenously determined structural breaks. The identi…ed dates are generally associated with external factors that include commodity price boom and burst cycles that the countries heavily depend on. The estimated results for eight of the countries indicate that there is a positive relationship between the current account and …scal de…cits and therefore, support the twin de…cits hypothesis. Results for the remaining four countries of Ethiopia, Kenya, South Africa and Uganda, on the other hand, show that the relationship between the two is negative. y We are very grateful to the editor and acknowledge the anonymous reviewers'useful and constructive comments.