Lester A. Mitscher

Bio: Lester A. Mitscher is an academic researcher from University of Kansas. The author has contributed to research in topics: Antimicrobial & DNA gyrase. The author has an hindex of 42, co-authored 200 publications receiving 6860 citations. Previous affiliations of Lester A. Mitscher include American Cyanamid & University of British Columbia.

Bacterial topoisomerase inhibitors: quinolone and pyridone antibacterial agents.

Abstract: 3.1. Chelation 564 3.2. Acid−Base Character 564 3.3. Photochemistry 565 4. In Vitro Antimicrobial Spectra 566 5. Structure−Activity Relationships 568 5.1. N-1 Ethyl Family 568 5.2. N-1 Cyclopropyl Family 568 5.3. N-1 to C-8 Bridged (Tricyclic) Family 568 5.4. N-1 Aryl Family 569 5.5. Positions C-2, C-3, and C-4 570 5.6. C-4a Substituted Analogues 571 5.7. C-5 Substituents 571 5.8. C-6 Substituents 571 5.9. C-7 Substituents 571 5.9.1. Piperazinyl and Related Moieties 572 5.9.2. Pyrrolidinyl and Related Moieties 572 5.9.3. Cyclobutylaminyl and Related Moieties 572 5.9.4. Bicycloaminyl Moieties 572 5.9.5. Carbon-Linked Substituents 572 5.10. Substituents at C-8 573 5.11. Resume of Structure−Activity Relationships of Quinolones 573

Glossary of terms used in medicinal chemistry (IUPAC Recommendations 1998)

Abstract: The objective of the glossary is to provide in a single document a consistent terminology and concise definitions of terms covering the various aspects of medicinal chemistry. This was felt necessary with regard to the rapid changes occuring in medicinal chemistry and also by the need to establish international definition standards. Effectively the possibility exists that in different countries certain terms may not have the same meaning, in such a case the creation of an internationally accepted definition is particularly justified. A Working Party belonging to the IUPAC Section on Medicinal Chemistry has therefore been assembled which prepared the present glossary. Concise but sufficiently explanatory definitions have been formulated for about one hundred commonly employed terms which can be considered of particular interest to the medicinal chemistry community. The glossary has been compiled in part from definitions proposed by the Working Party in part from earlier IUPAC glossaries and in part from well-accepted definitions taken from the literature but which were sometimes published in journals or books that may not be readily accessible. ALPHABETICAL ORDERED ENTRIES The glossary has been compiled in part from definitions proposed by the Working Party and in part from well-accepted definitions taken from the literature. In most cases, definitions given here are for specific areas of medicinal chemistry. Some definitions taken from the Glossary for Chemists of Terms Used in Biotechnology (Pure Appl. Chem., 1992, 64, 143-168) were also included, eventually in a slightly modified form; they are identified by an asterisk*. Others, which appear in the Glossary on Computational Drug Design (Pure Appl. Chem., 1997, 69, 1137-1 152) and in Glossary for Chemists of terms used in Toxicology (Pure Appl. Chem. 1993,65,2003-2122), are identified by a double** and a triple*** asterisk respectively. Active transport* Active transport is the carriage of a solute across a biological membrane from low to high concentration that requires the expenditure of (metabolic) energy. Address-message concept Address-message concept refers to compounds in which part of the molecule is required for binding (address) and part for the biological action (message). ADME Abbreviation for Absorption, Distribution, Metabolism, Excretion. (See also Pharmacokinetics; Drug disposition). Affinity Affinity is the tendency of a molecule to associate with another. The affinity of a drug is its ability to bind to its biological target (receptor, enzyme, transport system, etc.) For pharmacological receptors it can be thought of as the frequency with which the drug, when brought into the proximity of a receptor by diffusion, will reside at a position of minimum free energy within the force field of that receptor. 1130

The Organic Chemistry of Drug Synthesis

Abstract: The Organic Chemistry of Drug Synthesis , The Organic Chemistry of Drug Synthesis , کتابخانه دیجیتال جندی شاپور اهواز

Mechanism of inhibition of DNA gyrase by quinolone antibacterials: a cooperative drug--DNA binding model.

Abstract: We have proposed a cooperative quinolone-DNA binding model for the inhibition of DNA gyrase. The essential feature of the model is that bound gyrase induces a specific quinolone binding site in the relaxed DNA substrate in the presence of ATP. The binding affinity and specificity are derived from two unique and equally important functional features: the specific conformation of the proposed single-stranded DNA pocket induced by the enzyme and the unique self-association phenomenon (from which the cooperativity is derived) of the drug molecules to fit the binding pocket with a high degree of flexibility. Supporting evidence for and implications of this model are provided.

A modern look at folkloric use of anti-infective agents

Abstract: Infectious diseases are of ancient origin, and mankind has a venerable history of use of higher plant extracts for the therapy of such infections. Some such agents survive in use from earlier times--quinine, emetine, and sanguinarine, for example--but the modern use of fermentation-based antibiotics has greatly overshadowed work on agents from other sources. After a brief review of the present status of the field of antibiotics, this review focuses upon the present status of antimicrobial agents from higher plants with particular reference to agents from plants with a folkloric reputation for treatment of infections. In particular, recent work on the tropical genus Erythrina is emphasized. The use of modern microbiological techniques demonstrates that higher plants frequently exhibit significant potency against human bacterial and fungal pathogens, that many genera are involved, that many folkloric uses can be rationalized on this basis, that the active constituents are readily isolated by bioassay-directed techniques, that their chemical structures are types uncommon amongst fermentation-based agents but are familiar to natural product chemists, that their antimicrobial spectra are comparatively narrow but that their potency is often reasonable, that they are comparatively easy to synthesize and the unnatural analogues so produced can possess enhanced therapeutic potential and, thus, it is concluded that such work generates a gratifying number of novel lead structures and that the possibility of finding additional agents for human or agricultural use based upon higher plant agents is realistic.

Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: a national reconnaissance.

Abstract: To provide the first nationwide reconnaissance of the occurrence of pharmaceuticals, hormones, and other organic wastewater contaminants (OWCs) in water resources, the U.S. Geological Survey used five newly developed analytical methods to measure concentrations of 95 OWCs in water samples from a network of 139 streams across 30 states during 1999 and 2000. The selection of sampling sites was biased toward streams susceptible to contamination (i.e. downstream of intense urbanization and livestock production). OWCs were prevalent during this study, being found in 80% of the streams sampled. The compounds detected represent a wide range of residential, industrial, and agricultural origins and uses with 82 of the 95 OWCs being found during this study. The most frequently detected compounds were coprostanol (fecal steroid), cholesterol (plant and animal steroid), N,N-diethyltoluamide (insect repellant), caffeine (stimulant), triclosan (antimicrobial disinfectant), tri(2-chloroethyl)phosphate (fire retardant), and 4-nonylphenol (nonionic detergent metabolite). Measured concentrations for this study were generally low and rarely exceeded drinking-water guidelines, drinking-water health advisories, or aquatic-life criteria. Many compounds, however, do not have such guidelines established. The detection of multiple OWCs was common for this study, with a median of seven and as many as 38 OWCs being found in a given water sample. Little is known about the potential interactive effects (such as synergistic or antagonistic toxicity) that may occur from complex mixtures of OWCs in the environment. In addition, results of this study demonstrate the importance of obtaining data on metabolites to fully understand not only the fate and transport of OWCs in the hydrologic system but also their ultimate overall effect on human health and the environment.

Tetracycline Antibiotics: Mode of Action, Applications, Molecular Biology, and Epidemiology of Bacterial Resistance

Abstract: Tetracyclines were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydiae, mycoplasmas, rickettsiae, and protozoan parasites. They are inexpensive antibiotics, which have been used extensively in the prophlylaxis and therapy of human and animal infections and also at subtherapeutic levels in animal feed as growth promoters. The first tetracycline-resistant bacterium, Shigella dysenteriae, was isolated in 1953. Tetracycline resistance now occurs in an increasing number of pathogenic, opportunistic, and commensal bacteria. The presence of tetracycline-resistant pathogens limits the use of these agents in treatment of disease. Tetracycline resistance is often due to the acquisition of new genes, which code for energy-dependent efflux of tetracyclines or for a protein that protects bacterial ribosomes from the action of tetracyclines. Many of these genes are associated with mobile plasmids or transposons and can be distinguished from each other using molecular methods including DNA-DNA hybridization with oligonucleotide probes and DNA sequencing. A limited number of bacteria acquire resistance by mutations, which alter the permeability of the outer membrane porins and/or lipopolysaccharides in the outer membrane, change the regulation of innate efflux systems, or alter the 16S rRNA. New tetracycline derivatives are being examined, although their role in treatment is not clear. Changing the use of tetracyclines in human and animal health as well as in food production is needed if we are to continue to use this class of broad-spectrum antimicrobials through the present century.

Fluorine in pharmaceutical industry: fluorine-containing drugs introduced to the market in the last decade (2001-2011).

Abstract: Introduced to the Market in the Last Decade (2001−2011) Jiang Wang,† María Sańchez-Rosello,́‡,§ Jose ́ Luis Aceña, Carlos del Pozo,‡ Alexander E. Sorochinsky, Santos Fustero,*,‡,§ Vadim A. Soloshonok,* and Hong Liu*,† †Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China ‡Department of Organic Chemistry, Faculty of Pharmacy, University of Valencia, Av. Vicente Andreś Estelleś, 46100 Burjassot, Valencia, Spain Laboratorio de Molećulas Orgańicas, Centro de Investigacioń Príncipe Felipe, C/ Eduardo Primo Yuf́era 3, 46012 Valencia, Spain Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel Lardizab́al 3, 20018 San Sebastian, Spain IKERBASQUE, Basque Foundation for Science, Alameda Urquijo, 36-5 Plaza Bizkaia, 48011 Bilbao, Spain Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Murmanska Street 1, 02660 Kyiv-94, Ukraine

Oxidative stress and neurodegenerative diseases: a review of upstream and downstream antioxidant therapeutic options.

Abstract: Free radicals are common outcome of normal aerobic cellular metabolism. In-built antioxidant system of body plays its decisive role in prevention of any loss due to free radicals. However, imbalanced defense mechanism of antioxidants, overproduction or incorporation of free radicals from environment to living system leads to serious penalty leading to neuro-degeneration. Neural cells suffer functional or sensory loss in neurodegenerative diseases. Apart from several other environmental or genetic factors, oxidative stress (OS) leading to free radical attack on neural cells contributes calamitous role to neuro-degeneration. Though, oxygen is imperative for life, imbalanced metabolism and excess reactive oxygen species (ROS) generation end into a range of disorders such as Alzheimer's disease, Parkinson's disease, aging and many other neural disorders. Toxicity of free radicals contributes to proteins and DNA injury, inflammation, tissue damage and subsequent cellular apoptosis. Antioxidants are now being looked upon as persuasive therapeutic against solemn neuronal loss, as they have capability to combat by neutralizing free radicals. Diet is major source of antioxidants, as well as medicinal herbs are catching attention to be commercial source of antioxidants at present. Recognition of upstream and downstream antioxidant therapy to oxidative stress has been proved an effective tool in alteration of any neuronal damage as well as free radical scavenging. Antioxidants have a wide scope to sequester metal ions involved in neuronal plaque formation to prevent oxidative stress. In addition, antioxidant therapy is vital in scavenging free radicals and ROS preventing neuronal degeneration in post-oxidative stress scenario.