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K Koenig

Publications and source records attributed to K Koenig.

9 recordsLinked to original sources
PubMed1992

Physicochemical action of potassium-magnesium citrate in nephrolithiasis.

Effect of potassium-magnesium citrate on urinary biochemistry and crystallization of stone-forming salts was compared with that of potassium citrate at same dose of potassium in five normal subjects and five patients with calcium nephrolithiasis. Compared to the placebo phase, urinary pH rose significantly from 6.06 +/- 0.27 to 6.48 +/- 0.36 (mean +/- SD, p less than 0.0167) during treatment with potassium citrate (50 mEq/day for 7 days) and to 6.68 +/- 0.31 during therapy with potassium-magnesium citrate (containing 49 mEq K, 24.5 mEq Mg, and 73.5 mEq citrate per day). Urinary pH was significantly higher during potassium-magnesium citrate than during potassium citrate therapy. Thus, the amount of undissociated uric acid declined from 118 +/- 61 mg/day during the placebo phase to 68 +/- 54 mg/day during potassium citrate treatment and, more prominently, to 41 +/- 46 mg/day during potassium-magnesium citrate therapy. Urinary magnesium rose significantly from 102 +/- 25 to 146 +/- 37 mg/day during potassium-magnesium citrate therapy but not during potassium citrate therapy. Urinary citrate rose more prominently during potassium-magnesium citrate therapy (to 1027 +/- 478 mg/day from 638 +/- 252 mg/day) than during potassium citrate treatment (to 932 +/- 297 mg/day). Consequently, urinary saturation (activity product) of calcium oxalate declined significantly (from 1.49 x 10(-8) to 1.03 x 10(-8) M2) during potassium-magnesium citrate therapy and marginally (to 1.14 x 10(-8) M2) during potassium citrate therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Bioavailability of potassium and magnesium, and citraturic response from potassium-magnesium citrate.

The bioavailability of potassium and magnesium, and the citraturic response were determined for the new compound, potassium-magnesium citrate, in 14 normal volunteers. Results were compared to those of potassium citrate and magnesium citrate. Each subject participated in 4 phases of study: potassium-magnesium citrate, potassium citrate, magnesium citrate and potassium chloride. After stabilization on a metabolic diet, each subject ingested a single load of a test medication followed by timed urine collections for the next 24 hours. Test loads included potassium-magnesium citrate (49 mEq. potassium, 24.5 mEq. magnesium and 73.5 mEq. citrate), potassium citrate (50 mEq.), potassium chloride (50 mEq.) and magnesium citrate (25 mEq.) Urinary potassium, magnesium and citrate were measured for each collection period. Potassium-magnesium citrate provided an equivalent potassium bioavailability as potassium citrate and potassium chloride, and a comparable magnesium bioavailability as magnesium citrate. However, it gave the highest citraturic response, since the cumulative increment in urinary citrate post-load was 129 mg. daily for potassium-magnesium citrate, 105 mg. daily for potassium citrate and 35 mg. daily for magnesium citrate. Thus, potassium-magnesium citrate gave an optimum citraturic response in addition to providing absorbable potassium and magnesium.

Adult↗
PubMed1990

Xanthine dehydrogenase and 2-furoyl-coenzyme A dehydrogenase from Pseudomonas putida Fu1: two molybdenum-containing dehydrogenases of novel structural composition.

The constitutive xanthine dehydrogenase and the inducible 2-furoyl-coenzyme A (CoA) dehydrogenase could be labeled with [185W]tungstate. This labeling was used as a reporter to purify both labile proteins. The radioactivity cochromatographed predominantly with the residual enzymatic activity of both enzymes during the first purification steps. Both radioactive proteins were separated and purified to homogeneity. Antibodies raised against the larger protein also exhibited cross-reactivity toward the second smaller protein and removed xanthine dehydrogenase and 2-furoyl-CoA dehydrogenase activity up to 80 and 60% from the supernatant of cell extracts, respectively. With use of cell extract, Western immunoblots showed only two bands which correlated exactly with the activity stains for both enzymes after native polyacrylamide gel electrophoresis. Molybdate was absolutely required for incorporation of 185W, formation of cross-reacting material, and enzymatic activity. The latter parameters showed a perfect correlation. This evidence proves that the radioactive proteins were actually xanthine dehydrogenase and 2-furoyl-CoA dehydrogenase. The apparent molecular weight of the native xanthine dehydrogenase was about 300,000, and that of 2-furoyl-CoA dehydrogenase was 150,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of both enzymes revealed two protein bands corresponding to molecular weights of 55,000 and 25,000. The xanthine dehydrogenase contained at least 1.6 mol of molybdenum, 0.9 ml of cytochrome b, 5.8 mol of iron, and 2.4 mol of labile sulfur per mol of enzyme. The composition of the 2-furoyl-CoA dehydrogenase seemed to be similar, although the stoichiometry was not determined. The oxidation of furfuryl alcohol to furfural and further to 2-furoic acid by Pseudomonas putida Fu1 was catalyzed by two different dehydrogenases.

Chromatography↗
PubMed1965

Use of secondary data in numerical taxonomy of the genus Erwinia.

Lockhart, W. R. (Iowa State University, Ames), and Karen Koenig. Use of secondary data in numerical taxonomy of the genus Erwinia. J. Bacteriol. 90:1638-1644. 1965.-Numerical methods were used to study 34 bacterial cultures, including several species of Erwinia and selected representatives of other genera of the Enterobacteriaceae. Separate computations were made by use of varying amounts of secondary data (i.e., information regarding descriptive or quantitative characters applicable only to organisms yielding a positive result in another primary character). Substantially the same groupings of the test organisms were obtained in all computations, but definition of groups seemed to be more precise when secondary data were included. The results confirm proposals by other workers that E. carotovora, E. aroideae, E. atroseptica, and E. ananas be placed in a single species, separate from E. amylovora. Limited evidence suggests that E. nimipressuralis and E. chrysanthemi may be distinct species, and that some strains of E. amylovora are not very similar either to one another or to other members of the Enterobacteriaceae.

Chemical Phenomena↗