ABSTRACT
Glutathione transferase P1-1 is over expressed in some cancer cells and contributes to detoxification of anticancer drugs, leading to drug-resistant tumors. The inhibition of human recombinant GSTP1-1 by natural plant products was investigated using 10 compounds isolated from plants indigenous to Southern and Central Africa. Monochlorobimane and 1-chloro-2,4-dinitrobenzene were used to determine GST activity. Each test compound was screened at 33 and 100 µM. Isofuranonapthoquinone (1) (from Bulbine frutescens) showed 68% inhibition at 33 µM, and sesquiterpene lactone (2) (from Dicoma anomala) showed 75% inhibition at 33 µM. The IC(50) value of 1 was 6.8 µM. The mode of inhibition was mixed, partial (G site) and noncompetitive (H site) with K(i) values of 8.8 and 0.21 µM, respectively. Sesquiterpene 2 did not inhibit the CDNB reaction. Therefore, isofuranonapthoquinone 1 needs further investigations in vivo because of its potent inhibition of GSTP1-1 in vitro.
Subject(s)
Biological Products/pharmacology , Enzyme Inhibitors/pharmacology , Glutathione S-Transferase pi/antagonists & inhibitors , Isoenzymes/antagonists & inhibitors , Biological Products/chemistry , Biological Products/isolation & purification , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/isolation & purification , Glutathione S-Transferase pi/isolation & purification , Glutathione S-Transferase pi/metabolism , Humans , Isoenzymes/isolation & purification , Isoenzymes/metabolism , Kinetics , Molecular Conformation , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Recombinant Proteins/antagonists & inhibitors , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Stereoisomerism , Structure-Activity RelationshipABSTRACT
For many organizations, the emphasis today is the development of total service quality. To achieve these goals, organizations must not only apply the marketing concept to external targets, but also plan and control internal facets of their operations. The purpose of the present article is to develop the rationale for Total Service Quality (TSQ) based on an Internal Marketing Approach (IMA) as well as to posit the steps necessary to implement an IMA.
Subject(s)
Hospitals, Voluntary/standards , Marketing of Health Services/organization & administration , Organizational Culture , Total Quality Management/organization & administration , Consumer Behavior , Guidelines as Topic , Organizational Innovation , Personnel Administration, Hospital , Planning Techniques , Staff Development , United StatesABSTRACT
Customer expectations change as competition intensifies. The authors use adaptation and exchange theories to explain customer expectations, disconfirmation, and satisfaction as applied to three types of health care providers: physicians, walk-in clinics, and hospital emergency rooms. The results show how new referents for expectations challenge competitors to increase performance in order to match changing industry standards.
