published_or_final_version / abstract / toc / Botany / Doctoral / Doctor of Philosophy

published_or_final_version / Zoology / Master / Master of Philosophy

No description available.

ACE inhibitors have been widely used in the treatment of certain diseases of the cardiovascular system, the major use being hypertension, since all ACE inhibitors are prescribed for its treatment. ACE inhibitors is also used in the treatment of congestive heart failure. The angiotensin-converting enzyme (ACE) converts angiotensin 1 into angiotensin I1 and also stimulates the production of aldosterone (a hormone produced in the adrenal glands that influences salt and water retention by the kidneys, increasing blood volume and blood pressure). The cost benefit, cost-effectiveness and cost utility of ACE inhibitors have not been established. The objective of the study was to review and analyse the cost of ACE inhibitors by using a medical aid claims database. Data for the study population consisted of all prescriptions containing one or more ACE inhibitor combinations and were extracted from the central database of Interpharm datasystems for a period of one year, from 1 January 2001 to 31 December 2001. A total of 1 475 532 prescriptions containing a total of 2 953 244 ACE inhibitor items represented the study population. Through the analysis of the general medicine utilisation patterns that were obtained from the medicine claims database, it became evident that ACE inhibitor utilisation contributes considerably to the total prevalence and cost of all the medicine items available on the database. It constituted a total prevalence of 4,62% (n =1 475 532) of all the prescriptions and a total prevalence of 2,31% (n =2 953 244) for all the medicine items in the prescriptions with a cost of 3,65% (n =R379 91 1 472,OO). It was concluded that in the analysis of ACE inhibitors according to the innovator/generic classification, the majority of ACE inhibitors prescribed during the twelve-month period were for the innovator product, with a prevalence of 82,56% (n =68 162) and a cost of 89,11% (n =R13 863 080, 90). The utilisation of the generic ACE inhibitors, with a prevalence of 17,44% (n =68 162) and at a cost of 10,89% (n =R13 863 080, 90), was under-utilised. If the total number of prescriptions containing innovator ACE inhibitors could be generically substituted, (37,54%) R5 204 392,68 in cost expenditure could be saved over a twelve-month period. However, the fact that not all the innovator ACE inhibitors have generic equivalents available must be taken into account. If only the prescriptions containing ACE inhibitor items that have generic equivalents were to be substituted with their generic equivalents, R899 751.29(6.5%) would be saved. This was found by adding all the costs saved by substituting innovator drugs with their generics. Consequently, it can be concluded that the extensive use of the innovator ACE inhibitors could mean an exceptional increase in the cost expenditure associated with ACE inhibitor therapy. In completion of the study, recommendations were formulated as an aim to optimise the utilisation of ACE inhibitor generic equivalents. / Thesis (M. Pharm.)--North-West University, Potchefstroom Campus, 2004.

No description available.

No description available.

Endoproteinase Glu-C (EPGIu-C, EC 3.4.21.19), an enzyme isolated from the bacteria Staphylococcus aureus, has been found to cleave specifically at the carboxyl-terminal side of glutamyl and aspartyl peptide bonds. EPGIu-C has been reported to be stable and active in the presence of common denaturants such as guanidinium chloride, urea and sodium dodecyl sulfate (Drapeau, G.R. (1977) Methods in Enzymology, 47:189-191). In order assess the denaturant stability and activity of EPGIu-C, the effect of three common protein denaturants, guanidinium chloride, urea, and sodium dodecyl sulfate (SDS) on the proteolytic activity of EPGIu-C was studied.The kinetics of the hydrolyis reaction catalyzed by EPGIu-C was determined using the chromophoric substrate N-tBOC-L-glutamic acid-a-phenyl ester (BGPE).To compare theurea is significantly greater at the higher concentrations of urea. These results suggest that a complete cleavage of proteins substrate by EPGlu-C might occur more rapidly in 8.0 M urea than in 6.0 M GuCl, since EPGlu-C will be operating at a significantly higher catalytic efficiency in the urea solution. / Department of Chemistry

ACE inhibitors have been widely used in the treatment of certain diseases of the cardiovascular system, the major use being hypertension, since all ACE inhibitors are prescribed for its treatment. ACE inhibitors is also used in the treatment of congestive heart failure. The angiotensin-converting enzyme (ACE) converts angiotensin 1 into angiotensin I1 and also stimulates the production of aldosterone (a hormone produced in the adrenal glands that influences salt and water retention by the kidneys, increasing blood volume and blood pressure). The cost benefit, cost-effectiveness and cost utility of ACE inhibitors have not been established. The objective of the study was to review and analyse the cost of ACE inhibitors by using a medical aid claims database. Data for the study population consisted of all prescriptions containing one or more ACE inhibitor combinations and were extracted from the central database of Interpharm datasystems for a period of one year, from 1 January 2001 to 31 December 2001. A total of 1 475 532 prescriptions containing a total of 2 953 244 ACE inhibitor items represented the study population. Through the analysis of the general medicine utilisation patterns that were obtained from the medicine claims database, it became evident that ACE inhibitor utilisation contributes considerably to the total prevalence and cost of all the medicine items available on the database. It constituted a total prevalence of 4,62% (n =1 475 532) of all the prescriptions and a total prevalence of 2,31% (n =2 953 244) for all the medicine items in the prescriptions with a cost of 3,65% (n =R379 91 1 472,OO). It was concluded that in the analysis of ACE inhibitors according to the innovator/generic classification, the majority of ACE inhibitors prescribed during the twelve-month period were for the innovator product, with a prevalence of 82,56% (n =68 162) and a cost of 89,11% (n =R13 863 080, 90). The utilisation of the generic ACE inhibitors, with a prevalence of 17,44% (n =68 162) and at a cost of 10,89% (n =R13 863 080, 90), was under-utilised. If the total number of prescriptions containing innovator ACE inhibitors could be generically substituted, (37,54%) R5 204 392,68 in cost expenditure could be saved over a twelve-month period. However, the fact that not all the innovator ACE inhibitors have generic equivalents available must be taken into account. If only the prescriptions containing ACE inhibitor items that have generic equivalents were to be substituted with their generic equivalents, R899 751.29(6.5%) would be saved. This was found by adding all the costs saved by substituting innovator drugs with their generics. Consequently, it can be concluded that the extensive use of the innovator ACE inhibitors could mean an exceptional increase in the cost expenditure associated with ACE inhibitor therapy. In completion of the study, recommendations were formulated as an aim to optimise the utilisation of ACE inhibitor generic equivalents. / Thesis (M. Pharm.)--North-West University, Potchefstroom Campus, 2004.

Whey media, containing 2% (w/v) whey powder, 1% (w/v) glucose, and 0.5% (w/v) yeast extract, were fermented with nine Lactobacillus strains to produce angiotensin I-converting enzyme (ACE) inhibitory peptides. Lb. brevis, Lb. helveticus, and Lb. paracasei were most effective in producing whey hydrolysates that contained potent ACE inhibitors, with the inhibition rate ranging from 93.3 +/- 0.3 to 100%. The hydrolysates of three Lactobacillus strains were partially purified by dialysis (6,000--8,000 Da cut-off) to remove larger molecules, and subsequently subjected to RP-HPLC, equipped with a Delta Pak C18 column. Each chromatogram displayed at least three distinct peaks at the hydrophobic region of the elution profile. Altogether fourteen peaks were purified and assayed for ACE inhibitory activity. All peaks except one exhibited ACE inhibitory activities, with IC50 ranging from 5.3 +/- 0.1 to 2637.8 +/- 366.9mug/ml. Three of these peaks contained pentapeptides, which consisted of mostly hydrophobic or aromatic amino acids at the C-terminal.

The distribution of total phenolics, antioxidant capacity, monomeric anthocyanin, and ascorbic acid contents in the peel and flesh of Red Delicious, Granny Smith, and Fuji apples during a six-month storage period were determined. In addition, the effect of 1-MCP (1-Methyl cyclopropene) on these parameters of the edible portion of apples during storage was also investigated. Two different assays were employed to determine antioxidant activities: the spectrofluorometric-based Oxygen Radical absorbing Capacity (ORAC) and the spectrophotometric-based Ferric Reducing Antioxidant Power (FRAP). Total phenolics were measured using the Folin-Ciocalteau method. A determination of monomeric anthocyanin content was also performed using the pH-differential method for Red Delicious and Fuji apples. Antioxidant activity was predominantly observed in the aqueous fraction and was attributed to polyphenolics. Antioxidant activities were highest in the peel, with Red Delicious peel having the highest values, presumably due to anthocyanin pigments. At zero time month storage, the ORAC, FRAP, total phenolics, and total monomeric anthocyanin contents of Red Delicious peel were: 37.7 μmol T.E./g, 62.7 μmol T.E./g, 6.63 mg/g GAE, and 26.4 mg/100g, respectively. The three tested cultivars were significantly different with respect to ORAC, FRAP, total phenolics, and monomeric anthocyanin contents. 1-MCP treatment did not have a significant influence on antioxidant activities and monomeric anthocyanin contents of the three cultivars during storage. Storage did not have significant influence on ORAC values of the edible portion of apple, however it had significant influence on the FRAP values. The contribution of ascorbic acid to the total antioxidant capacity was small. / Graduation date: 2003