Search PubMed⌕ Search

Biomedical subjects

D Moore

Publications and source records attributed to D Moore.

At least 343 records · Page 19Linked to original sources
PubMed1977

Factors affecting the amount and the activity of the glutamate dehydrogenases of Coprinus cinereus.

Kinetic analyses done with cell-free extracts of this basidiomycete fungus showed that the NADP-linked glutamate dehydrogenase exhibited positively co-operative interactions with the substrates 2-oxoglutarate and NADPH, negatively co-operative kinetics with NADP+ and was extremely sensitive to inhibition of deamination activity by ammonium and/or ammonia. The NAD-linked enzyme showed positive co-operativity with NADH, Michaelis-Menten kinetics with all other substrates and was subject only to mild inhibitions by the reaction products. Considered together with the values of the Michaelis constants, these results indicate that the former enzyme is primarily concerned with the amination of 2-oxoglutarate when the concentration of this substrate exceeds about 4 mM, while the NAD-linked enzyme is able to aminate or deaminate as metabolic conditions require. Synthesis of both enzymes was repressed by addition of carbamyl phosphate or N-acetyl-glutamate to mycelial cultures growing in media containing glucose and ammonium as carbon and nitrogen sources. Growth in media containing urea results in repression of the NADP-linked glutamate dehydrogenase and derepression of the NAD-linked enzyme. Such results indicate a connexion between the glutamate dehydrogenases and the urea cycle. It is suggested that under normal conditions of growth on complex media nitrogen is assimilated in the form of amino acids and that the glutamate dehydrogenases act in support of transaminases to allow this process to continue, and in support of the urea cycle to allow the disposal of excess nitrogen.

Agaricales↗
PubMed1976

Electrophoresis of human multiple myeloma and Waldenström's macroglobulinemia sera in sodium dodecyl sulfate polyacrylamide gels.

Sera from normal persons and patients with IgA, IgD, IgG, and IgM monoclonal gammopathies were electrophoresed in polyacrylamide gels containing sodium dodecyl sulfate. The gels were stained with Coomassie blue or were used for immunodiffusion. By this method IgG multiple myeloma and IgM Waldenström's macroglobulinemia sera were readily distinguished by electrophoresis alone, whereas IgA and IgD myeloma sera were distinguished by further immunodiffusion against anti-alpha-chain antibody and anti-delta-chain antibody.

Electrophoresis, Polyacrylamide Gel↗
PubMed1976

Effect of topically applied pilocarpine on tear film pH.

Changes in tear film pH were observed during the 1st hr after instillation of pilocarpine in various dosage forms to the rabbit eye. In anesthetized rabbits, with periodic blinking induced electrically, commercial formulations of pilocarpine salts applied as drops or a spray acutely lowered tear film pH by 1.1-1.6 pH units. The pH remained below pretreatment levels for 45-greater than 60 min after instillation. Pilocarpine base, administered continuously at the rates of 20 or 80 mug/hr from ocular therapeutic systems, had little or no effect on tear film pH in this same animal preparation. The reduction in tear film pH produced by pilocarpine eyedrops or spray solution is attributable to the acid pH and buffer capacity of these solutions. Delivery of pilocarpine base without pH change was achieved with ocular therapeutic systems, because the drug (pKa = 7.07) was delivered free, or virtually so, of excipients. These observed differences in tear film pH after application may partially explain the four- to eightfold reduction in total effective pilocarpine dose with ocular therapeutic systems compared to eyedrops or spray, since the cornea is less permeable to ionized than to unionized molecules.

Administration, Topical↗
PubMed1975

Comparative distribution of pilocarpine in ocular tissues of the rabbit during administration by eyedrop or by membrane-controlled delivery systems.

We compared the patterns of pilocarpine distribution in the rabbit eye during two regimens that were comparably efficacious in human clinical use: an administration of 2% pilocarpine nitrate eyedrops, every six hours, for four and eight days, and a continuous delivery of pilocarpine for as long as eight days, at 20 mug/hr, from a membrane-controlled delivery system in the inferior cul-de-sac. Pilocarpine labeled with radioactive carbon (14C) was used as a tracer. With administration of eyedrops, 14C levels in ocular tissues rose and fell within each six-hour interval between eyedrops, but with the delivery system, 14C levels remained constant over the two- to eight-day period. In each tissue, the 14C level within the first hour after the most recently administered eyedrop always exceeded the constant level maintained by the delivery system. Three to six hours after eyedrop administration, the 14C levels in cornea, iris, and sclera were approximately equal to those maintained by the delivery system. However, in lens, vitreous humor, and conjunctiva, the 14C levels were always two to five times higher with eyedrop administration than with the delivery system. Only aqueous humor showed a significantly lower 14C level with eyedrops than with the delivery system, occurring late in the interval between eyedrops. Compared to eyedrop administration, the membrane-controlled delivery system produced drug levels in ocular tissues that were constant rather than variable with time, and appreciably lower in tissues where the drug made no known contribution to the reduction of pressure.

Administration, Topical↗
PubMed1974

A study of the influence during trituration of air-borne impurities on the strength of amalgam.

The purpose of this study was to determined the effect of air-borne gaseous impurities, introduced during trituration, on the strength of amalgams. Four experiments were conducted. Each experiment consisted of a control group (1) in which the amalgam was triturated in air and an experimental group (2) in which the amalgam was triturated in argon, an inert gas. Standard specimens yielded mean diametral tensile strengths of 5950 psi (1) and 6603 psi (2). Hand compacted specimens yielded mean diametral tensile strengths of 5829 psi (1) and 6412 psi (2). Standard specimens yielded mean compacted hydraulically yielded mean uniaxial tensile strengths of 10,928 psi (1) and 11,660 psi (2). Statistically, the differences between the means for each experiment are significant. Hence, trituration in an inert gas has been shown to be an effective method for increasing the strength of amalgam.

Air Pollution↗