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Biomedical subjects

A King

Publications and source records attributed to A King.

At least 415 records · Page 23Linked to original sources
PubMed1983

The use of cluster analysis in determining possible enzyme-substrate interactions with reference to nucleoside diphosphatase activity of Golgi membranes.

The relative effectiveness of deoxyribonucleoside diphosphates, ribonucleoside diphosphates and phosphorylated B vitamins as substrates of the nucleoside diphosphatase of Golgi membranes have been determined. The substrates have been classified by cluster analysis. These findings suggest that a base ketone group and the 3'-OH of the substrates are important in promoting catalytic effectiveness, possibly by promoting hydrogen bonding during enzyme-substrate complex formation.

Acid Anhydride Hydrolases↗
PubMed1983

Cefotetan: in-vitro antibacterial activity and susceptibility to beta-lactamases.

The in-vitro antibacterial activity of cefotetan was assessed against recent clinical isolates of common bacteria and also against reference strains that produced known beta-lactamases. The compound was active against most staphylococci (MICs 4 to 8 mg/l) though methicillin-resistant strains were less sensitive. It was also generally active against streptococci (MICs mostly in the range 1 to 16 mg/l). However, enterococci and penicillin-resistant pneumococci were resistant. Cefotetan was highly active against enterobacteria, with 75% of isolates inhibited by 0.5 mg/l and 90% inhibited by 4 mg/l. It was also highly active against Haemophilus influenzae (MICs 0.5 to 4 mg/l) and Neisseria gonorrhoeae (MICs 0.06 to 2 mg/l) but had relatively poor activity against Acinetobacter spp. (MICs mostly 4 to 128 mg/l). Cefotetan had little useful activity against Pseudomonas aeruginosa (MICs 16 to 512 mg/l) but was more active against most other pseudomonads. Cefotetan had moderate activity against the Bacteroides fragilis group (MICs mostly less than or equal to 32 mg/l), though Bact. fragilis sensu stricto and Bact. vulgatus were more sensitive (MICs usually less than or equal to 4 mg/l). It was more active against most other anaerobes, though its activity was always exceeded by that of ampicillin. Cefotetan possessed a high degree of resistance to both plasmid-mediated and chromosomally-determined beta-lactamases.

Anti-Bacterial Agents↗
PubMed1983

Reduced sensitivity to beta-lactam antibiotics arising during ceftazidime treatment of Pseudomonas aeruginosa infections.

Pseudomonas aeruginosa isolated from two patients with empyema and one with bronchopneumonia became less sensitive after treatment with ceftazidime, while Ps. aeruginosa persisted in a patient with an infected compound fracture of the tibia treated with ceftazidime but did not become less sensitive. The reduction in sensitivity to ceftazidime, which was small, was accompanied by resistance to azlocillin but there are little reduction in sensitivity to carbenicillin. The resistant strains produced increased amounts of the chromosomally-mediated cephalosporinase produced by most isolates of Ps. aeruginosa. Variants with reduced sensitivity to ceftazidime, which resembled those that developed in vivo, were selected in vitro from each of the initial ceftazidime-sensitive isolates.

Adult↗
PubMed1982

In vitro antibacterial activity of norfloxacin (MK-0366).

The in vitro activity of norfloxacin (MK-0366) compared with that of beta-lactam antibiotics and, where appropriate of gentamicin or metronidazole was assessed against recent clinical isolates of common bacteria. The compound was highly active against most enterobacteria (minimal inhibitory concentrations [MICs], 0.008 to 32 micrograms/ml; 90% inhibited by 0.25 micrograms/ml), Haemophilus influenzae (MICs, 0.03 to 0.12 micrograms/ml), and Neisseria gonorrhoeae (MICs, 0.008 to 0.016 micrograms/ml). It was also active against Pseudomonas aeruginosa (MICs, 0.12 to 2 micrograms/ml), most other pseudomonads (MICs, 0.03 to 32 micrograms/ml), and Acinetobacter calcoaceticus (MICs 0.06 to 4 micrograms/ml). Norfloxacin was somewhat less active against staphylococci (MICs, 0.25 to 4 micrograms/ml; 1 microgram/ml required to inhibit 50% of isolates) and streptococci (MICs, 0.5 to 64 micrograms/ml). Members of the Bacteroides fragilis group of anaerobes were relatively resistant to norfloxacin (MICs, 8 to 128 micrograms/ml), as were most other anaerobes.

Aerobiosis↗
PubMed1980

In vitro antibacterial activity and susceptibility of cefsulodin, an antipseudomonal cephalosporin, to beta-lactamases.

Cefsulodin sodium (SCE-129, CGP-7174/E), active in minimum inhibitory concentrations (MICs) of 0.5 to 64 microgram/ml, was about 16- to 32-fold more active than carbenicillin against Psuedomonas aeruginosa. It was also active against P. diminuta, P. maltophilia, P. paucimobilis, and P. pseudoalcaligenes (MICs of 1 to 32 microgram/ml) but not against other species of Pseudomonas or other gram-negative bacteria. Except with highly carbenicillin-resistant isolates, MICs of cefsulodin for P. aeruginosa were little affected by an increase in the inoculum. With a small inoculum, minimum bactericidal concentrations (MBCs) were the same as or twice the MIC, but increasing the inoculum had a greater effect on the MBC than on the MIC. Cefsulodin was not hydrolyzed by the beta-lactamase induced in P. aeruginosa by growth in the presence of benzylpenicillin and was a poor substrate for beta-lactamases from Enterobacter cloacae and Proteus morganii. However, it was hydrolyzed, albeit slowly, by the beta-lactamase produced by most of our highly carbenicillin-resistant isolates of P. aeruginosa and by TEM-type beta-lactamases.

Bacteria↗
PubMed1980

In vitro antibacterial activity and susceptibility of the cephalosporin Ro 13-9904 to beta-lactamases.

The in vitro activity of Ro 13-9904 was assessed against clinical isolated of common bacteria. Its activity against most enterobacteria was similar to that of cefotaxime and moxalactam, but it was even more active than these compounds against all Proteus species. It was also highly active against Haemophilus influenzae and Neisseria gonorrhoeae, including beta-lactamase producers. Like cefotaxime and moxalactam, Or 13-9904 was approximately eightfold more active than carbenicillin against most isolates of Pseudomonas aeruginosa and also active against highly carbenicillin-resistant isolates, but it was relatively inactive against moderately carbenicillin-resistant isolates. Ro 13-9904 also resembled cefotaxime and moxalactam in that it was active, though less so than cephaloridine, against staphylococci and streptococci, except for methicillin-resistant staphylococci and Streptococcus faecalis, which were resistant to it. It was less active than cefoxitin but slightly more active than ampicillin against both Bacteroides fragilis and other Bacteroides spp. Ro 13-9904 was resistant to most beta-lactamases but was attacked by enzymes from B. fragilis, isolates of indole-positive Proteus species, and also by a cefoxitin-hydrolyzing enzyme from an isolate of Enterobacter cloacae.

Bacteria↗
PubMed1979

A taxonomic study of clinical isolates of Pseudomonas pickettii, 'P. thomasii' and 'group IVd' bacteria.

On the basis of cluster analysis, average similarities within and between groups, and DNA base composition of selected strains, Pseudomonas pickettii appeared to be a distinct species comprising several biotypes. Although some or all of these biotypes, represented by subclusters in our computer study, may ultimately warrant recognition as separate species, our results were not conclusive enough to warrant such a proposal at present. Most strains tentatively named 'P. thomasii' could be included in P. pickettii so that the name P. pickettii, which was validly published whilst 'P. thomasii' was not, takes priority over 'P. thomasii'. Strains of Group Va (Tatum et al., 1974) examined were also included in P. pickettii. Group IVd (King, 1964) did not appear to be a natural group but some of the strains could also be included in P. pickettii.

Base Composition↗