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Biomedical subjects

D Stewart

Publications and source records attributed to D Stewart.

At least 361 records · Page 20Linked to original sources
PubMed1976

Observations in man on some pharmacologic features of cefamandole.

Comparative studies of cefamandole and cephalothin were carried out in 32 cancer patients. After rapid intravenous injection of 1 gm cefamandole or cephalothin, the peak mean serum concentrations in 11 patients achieved at 0.25 hr were 103.4 mcg/ml and 56.7 mcg/ml, respectively. Except at 6 hr, the serum concentration of cefamandole was higher (p less than 0.05) at all times. The terminal half-lives (t 1/2) were similar, being 1.2 hr for cefamandole and 1.0 hr for cephalothin. Cefamandole, 1 gm intramuscularly, induced a peak mean serum concentration of 26.6 mcg/ml at 1 hr, with a slow decay. Intermittent cefamandole (2 gm intravenously every 6 hr) induced very high mean serum concentrations (7 patients), but at 4 hr the concentrations were similar to those after 1 gm intravenously. Per cent of urinary excretion was similar for both drugs regardless of dose and mode of administration. Continuous-infusion cefamandole or cephalothin (2 gm loading followed by 2 gm every 6 hr) in 14 patients showed consistently higher serum concentrations for cefamandole (p less than 0.05) over a 5-day period. There was no evidence of drug accumulation in the multiple-dose studies. Both the single- and multiple-dose schedules were well tolerated.

Adolescent↗
PubMed1976

Comparative in vitro activity of cephalosporins.

The in vitro activity of cephalexin, cephaloridine, cephalothin, cephapirin, cefoxitin, cephamycin C, cepharadine and cefazolin was determined against 443 isolates of bacteria. At a concentration of 12.5 mug/ml, all of the cephalosporins inhibited more than 60% of the isolates of Klebsiella pneumoniae. At the same concentration, cephalexin, cephaloridine, cephalothin, cephapirin, cephamycin C and cefazolin inhibited more than 90% of isolates of proteus mirabilis. All of the cephalosporins except cephalothin and cephapirin inhibited over 60% of isolates of Escherichia coli at a concentration of 12.5 mug/ml. Cefoxitin was the most active cephalosporin against gram-negative bacilli. There was substantial differences in the activity of cephalosporins against gram-positive cocci. Cephaloridine was the most active cephalosporin against these organisms. There was considerable fluctuation in the proportion of isolates of gram-negative bacilli susceptible to these cephalosporins from year to year, but there was no evidence to suggest that the number of resistant isolates was increasing.

Cephalosporins↗
PubMed1975

Feasibility of administering aminoglycoside antibiotics by continuous intravenous infusion.

Eleven patients each received gentamicin sulfate, tobramycin, and sisomicin by continuous intravenous infusion after an initial loading dose. Subsequent doses of antibiotic were adjusted in an attempt to maintain constant serum concentrations. There was considerable variation in the serum concentration from patient to patient and in the same patient from day to day with each drug. Although the dosages of gentamicin sulfate and tobramycin were similar, the serum concentrations of the latter drug were consistently lower. Despite the daily administration of doses of at least 300 mg of gentamicin and tobramycin per m(2) and 160 mg of sisomicin per m(2), nephrotoxicity occurred in only three patients. This is a low frequency of nephrotoxicity, considering the dosages of drug administered. Although therapeutic efficacy was not an objective of this study, 8 of 11 documented infections were cured. This approach to the administration of aminoglycoside antibiotics deserves therapeutic trials.

Adolescent↗
PubMed1975

In vitro activity of sisomicin, an aminoglycoside antibiotic, against clinical isolates.

Sisomicin, a new aminoglycoside antibiotic which is produced by Micromonospora myoensis, was studied against 565 clinical isolates of gram-negative bacilli and gram-positive cocci. With the exception of Serratia marcescens, over 90% of isolates of gram-negative bacilli were inhibited by 1.56 mug/ml or less of sisomicin. Sisomicin was slightly more active than gentamicin and tobramycin aganist isolates of Escherichia coli, Proteus mirabilis and Klebsiella spp. It was substantially more active than butirosin and kanamycin against all gram-negative bacilli. Isolates of gram-negative bacilli which were resistant to gentamicin and tobramycin were also resistant to sisomicin. Most of these isolates were sensitive to amikacin.

Aminoglycosides↗
PubMed1973

In vitro studies of BB-K8, a new aminoglycoside antibiotic.

BB-K8, an aminoglycoside antibiotic which is a derivative of kanamycin, was tested in vitro against 466 clinical bacterial isolates. Over 90% of gram-negative bacilli, except Proteus spp., were inhibited by 3.12 mug of BB-K8 per ml. This antibiotic was consistently more active than kanamycin but less active than tobramycin or gentamicin. Unlike kanamycin, BB-K8 was active against Pseudomonas aeruginosa. Eleven of 19 isolates resistant to either gentamicin or tobramycin, or both, were susceptible to BB-K8.

Aminobutyrates↗
PubMed1972

In vitro studies of tobramycin.

The in vitro activity of tobramycin was studied against 457 clinical isolates of gram-negative bacilli and 151 clinical isolates of gram-positive cocci. The vast majority of the gram-negative bacilli was inhibited by tobramycin at a concentration of 1.56 mug or less per ml. Only a few isolates of Staphylococcus aureus and no isolates of Streptococcus pyogenes or Diplococcus pneumoniae were susceptible to this drug. Tobramycin was generally more active than gentamicin sulfate against gram-negative bacilli, although organisms resistant to gentamicin sulfate were also resistant to tobramycin. The major difference between the two drugs was the greater activity of tobramycin against Pseudomonas aeruginosa.

Aminoglycosides↗
PubMed1972

Studies on the prekallikrein-bradykininogen system in liver disease.

The plasma prekallikrein-bradykininogen system was studied in 45 patients with chronic liver disease since its activation with increased liberation of kinin into the plasma could account for some of the clinical manifestations of cirrhosis, namely, vasodilatation, hypotension, and increased capillary permeability.A significant reduction in plasma bradykininogen was found in the cirrhotic patients as compared with control groups of normal subjects and hospital inpatients. The mean plasma prekallikrein was not significantly different and only five patients with liver disease had reduced levels. The most likely explanation for the low plasma bradykininogen was impairment of synthesis by the cirrhotic liver, the usually normal prekallikrein levels making the other possibility of increased activation of bradykininogen to bradykinin in the plasma less likely.

Bradykinin↗
PubMed1971

In vitro studies of semisynthetic alpha-(substituted-ureido) penicillins.

The activity of three alpha-(substituted-ureido) penicillins was evaluated in vitro against 599 clinical isolates of gram-negative bacilli, by use of the broth-dilution technique. At a concentration of 12.5 mug or less/ml, BL-P1597 inhibited 90% of isolates of Pseudomonas sp., 56% of Enterobacter sp., 67% of indole-positive Proteus spp., 72% of Escherichia coli, and 85% of Proteus mirabilis. BL-P1654 had similar activity, whereas BL-P1532 was much less active. At a concentration of 25 mug or less/ml, BL-P1597 also inhibited nearly 60% of isolates of Klebsiella sp. and nearly 40% of Serratia sp. BL-P1597 and BL-P1654 were as active as ampicillin and carbenicillin against E. coli and P. mirabilis. They were less active than carbenicillin against indole-positive Proteus spp. Both drugs were substantially more active than carbenicillin against Pseudomonas sp. A strain of Pseudomonas sp. which developed resistance to carbenicillin also developed resistance to the alpha-(substituted-ureido) penicillins simultaneously.

Agar↗
PubMed1969

In vitro studies of a new semisynthetic penicillin, 6-(d-alpha-sulfoaminophenylacetamido)-penicillanic acid.

The activity of 6-(D-alpha-sulfoaminophenylacetamido)-penicillanic acid was determined against 357 clinical isolates of gram-negative bacilli by use of the tube-dilution technique. The majority of the isolates of Pseudomonas species were inhibited by 200 mug/ml or less of this antibiotic. Most of the isolates of Escherichia coli had a minimal inhibitory concentration of 50 mug/ml or less. Seventy-three per cent of the isolates of P. mirabilis, 40% of the isolates of P. morganii, and 45% of the isolates of Enterobacter species were inhibited by 12.5 mug/ml or less, whereas most of the isolates of Klebsiella species and Serratia species were resistant. The activity of this semisynthetic penicillin was affected by the size of the inoculum. The drug was bactericidal against all isolates of E. coli and Proteus species that were sensitive to it, but it was bactericidal against only 32% of the sensitive isolates of Pseudomonas species.

Bacteria↗