Browsing by Author "Maher, Timothy J."
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Item Characterization of phentermine and related compounds as monoamine oxidase (MAO) inhibitors(Pergamon-Elsevier Science Ltd, 2000-06-15) Maher, Timothy J.; Wurtman, Richard J.; Ulus, İsmail H.; Uludağ Üniversitesi/Tıp Fakültesi/Farmakoloji ve Klinik Farmakolojisi Bölümü.; D-5340-2015Phentermine was shown in the 1970s to inhibit the metabolism of serotonin by monoamine oxidase (MAO), but never was labeled as an MAO inhibitor; hence, it was widely used in combination with fenfluramine, and continues to be used, in violation of their labels, with other serotonin uptake blockers. We examined the effects of phentermine and several other unlabeled MAO inhibitors on MAO activities in rat lung, brain, and liver, and also the interactions of such drugs when administered together. Rat tissues were assayed for MAO-A and -B, using serotonin and beta-phenylethylamine as substrates. Phentermine inhibited serotonin-metabolizing (MAO-A activity in all three tissues with K-i values of 85-88 mu M. These potencies were similar to those of the antidepressant MAO inhibitors iproniazid and moclobemide. When phentermine was mixed with other unlabeled reversible MAO inhibitors (e.g. pseudoephedrine, ephedrine, norephedrine; estradiol benzoate), the degree of MAO inhibition was additive. The cardiac valvular lesions and primary pulmonary hypertension that have been reported to be associated with fenfluramine-phentermine use may have resulted from the intermittent concurrent blockage of both serotonin uptake and metabolism.Item Dietary crude lecithin increases systemic availability of dietary docosahexaenoic acid with combined intake in rats(Wiley, 2016-02-29) van Wijk, Nick; Balvers, Martin; Maher, Timothy J.; Sijben, John W. C.; Broersen, Laus M.; Cansev, Mehmet; Uludağ Üniversitesi/Tıp Fakültesi/Eczacılık Anabilim Dalı.; 0000-0003-2918-5064; M-9071-2019; 8872816100Crude lecithin, a mixture of mainly phospholipids, potentially helps to increase the systemic availability of dietary omega-3 polyunsaturated fatty acids (n-3 PUFA), such as docosahexaenoic acid (DHA). Nevertheless, no clear data exist on the effects of prolonged combined dietary supplementation of DHA and lecithin on RBC and plasma PUFA levels. In the current experiments, levels of DHA and choline, two dietary ingredients that enhance neuronal membrane formation and function, were determined in plasma and red blood cells (RBC) from rats after dietary supplementation of DHA-containing oils with and without concomitant dietary supplementation of crude lecithin for 2-3 weeks. The aim was to provide experimental evidence for the hypothesized additive effects of dietary lecithin (not containing any DHA) on top of dietary DHA on PUFA levels in plasma and RBC. Dietary supplementation of DHA-containing oils, either as vegetable algae oil or as fish oil, increased DHA, eicosapentaenoic acid (EPA), and total n-3 PUFA, and decreased total omega-6 PUFA levels in plasma and RBC, while dietary lecithin supplementation alone did not affect these levels. However, combined dietary supplementation of DHA and lecithin increased the changes induced by DHA supplementation alone. Animals receiving a lecithin-containing diet also had a higher plasma free choline concentration as compared to controls. In conclusion, dietary DHA-containing oils and crude lecithin have synergistic effects on increasing plasma and RBC n-3 PUFA levels, including DHA and EPA. By increasing the systemic availability of dietary DHA, dietary lecithin may increase the efficacy of DHA supplementation when their intake is combined.Item Does phentermine inhibit monoamine oxidase? Reply(Elsevier, 1999-04-17) Maher, Timothy J.; Wurtman, Richard J.; Ulus, İsmail Hakkı; Uludağ Üniversitesi/Tıp Fakültesi/Farmakoloji Anabilim Dalı.; D-5340-2015; 7004271086Item Phentermine and other monoamine-oxidase inhibitors may increase plasma serotonin when given with fenfluramines(Lancet, 1999-01-02) Maher, Timothy J.; Wurtman, Richard J.; Ulus, İsmail Hakkı; Uludağ Üniversitesi/Tıp Fakültesi/Farmakoloji Anabilim Dalı.; D-5340-2015