Cefoperazone and cefotiam--two new cephalosporins: an in-vitro comparison

The in vitro activity of cefoperazone (CPZ) and cefotiam (CTM) was compared to other available cephalosporins. Using an agar dilution procedure both CTM and CPZ were more active against the Enterobacteriaceae tested than cefoxitin, cefuroxime and cefazolin; CTM being slightly more active than CPZ, in particular against Klebsiella spp Haemophilus influenzae were more susceptible to CPZ. CTM had no activity against Pseudomonas aeruginosa but CPZ exhibited considerable activity (mode MIC 4 mg/l). Against Bacteroides fragilis CPZ had a similar activity to cefuroxime, but CTM was less active. CTM was about twice as active as CPZ against Staphylococcus aureus, cefazolin being the most active agent tested. The MBC was about twice the MIC for each compound and the presence of 75% serum had only a modest effect on the MIC and MBC. The protein binding of CPZ was 94% and CTM 62%.

Comparison of sensititre dried microtitration trays with a standard agar method for determination of minimum inhibitory concentrations of antimicrobial agents

A total of 222 clinical isolates were used to test the accuracy of Sensititre dried microtitration trays for determining minimum inhibitory concentrations (MICs) of antimicrobial agents. In comparison with an agar dilution technique, 89.5% of all the pairs of results were within one doubling dilution. The 2,420 pairs of MIC results with finite values gave a corresponding figure of 86.8%. Exclusion of sulfisoxazole results, which demonstrated a significant interlaboratory variation in accuracy, raised this value to 89.1%. Very good differentiation of beta-lactamase-producing strains of Staphylococcus aureus (24 of 24 giving an MIC greater than or equal to 0.25 micrograms/ml) and Haemophilus influenzae (3 of 3 giving an MIC greater than or equal to 32 micrograms/ml) was obtained with the Sensititre system. This method also clearly distinguished erythromycin-resistant S. aureus strains (7 of 7 giving an MIC greater than 32 micrograms/ml) from the susceptible strains (26 of 28 giving an MIC less than or equal to 0.5 microgram/ml plus 1 strain at 1.0 microgram/ml and 1 at 2.0 micrograms/ml). Sensititre offers an accurate and convenient method of determining MICs comparable to those obtained with the agar dilution procedure, with the advantage of an extended shelf life when stored at room temperature.

Comparison of in vitro activity of GR 20263, a novel cephalosporin derivative, with activities of other beta-lactam compounds

The in vitro activity of GR 20263, a new cephalosporin, was compared primarily with the activities of moxalactam (LY 127935), cefotaxime, cefoxitin, cefuroxime, and cefazolin against 293 clinical isolates of a variety of gram-positive and -negative bacteria. The minimal inhibitory concentrations of GR 20263 for 90% of group isolates were between 0.06 and 0.5 microgram/ml for the Enterobacteriaceae, Haemophilus influenzae, Neisseria gonorrhoeae, and Lancefield group A beta-hemolytic streptococci; 2 micrograms/ml for Pseudomonas aeruginosa; 16 micrograms/ml for Staphylococcus aureus; and in excess of 128 micrograms/ml for Bacteroides fragilis and Lancefield group D streptococci. In comparison with the other agents, GR 20263 was markedly more active against the Enterobacteriaceae than cefuroxime, cefoxitin, and cefazolin, but marginally less active than moxalactam or cofotaxime. Aganist S. aureus, cefazolin was 16-fold and cefotaxime was 4-fold more active than GR 20263 and moxalactam. GR 20263 was eight-fold more active than cefotaxime and moxalactam against P. aeruginosa.

UK31214, a new aminoglycoside and derivative of kanamycin B

The in vitro activity of UK31214, a kanamycin B derivative, was studied against 250 recent isolates and compared with other aminoglycosides. Against the Enterobacteriaceae (with the exception of Proteus mirabilis and Providencia stuartii) UK31214 and amikacin had similar degrees of activity (mode minimum inhibitory concentration [MIC], 1 microgram/ml). Proteus mirabilis and P. stuartii strains were four- to eight-fold more susceptible to amikacin than to UK31214. Pseudomonas aeruginosa strains were equally susceptible to both amikacin and UK31214 (mode MIC, 4 microgram/ml), but tobramycin was the most active antimicrobial agent tested (mode MIC, 0.25 microgram/ml). The gentamicin-resistant strains of P. aeruginosa were equally susceptible to UK31214 and amikacin. Strains of Staphylococcus aureus were more susceptible to gentamicin or tobramycin than to UK31214 or amikacin (mode MIC, 0.5 microgram/ml). A synergistic interaction between UK31214 and carbenicillin was demonstrated.

Activity of the cefotaxime (HR756) desacetyl metabolite compared with those of cefotaxime and other cephalosporins

The desacetyl metabolite (DES) of cefotaxime (HR756) is formed in vivo to a significant extent. The in vitro activities of DES, the parent compound, and cefazolin, cefoxitin, and cefuroxime were compared against 70 bacterial isolates. DES was found to possess approximately 1/10th the activity of the parent compound against the common Enterobacteriaceae, but was somewhat more active than the other three compounds tested. DES had no useful activity against Pseudomonas aeruginosa and was less active than cefotaxime or cefoxitin against Staphylococcus aureus or Bacteroides fragilis. Because DES may accumulate in renal failure or be concentrated in the biliary tract, its antimicrobial activity may have considerable clinical significance.

The enzymatic nature of human c1r: a subcomponent of the first component of complement

The esterase activity of the C1r subcomponent of the first component of complement has been investigated. C1r was found to hydrolyze two amino acid methyl esters; N-acetyl-L-arginine methyl ester and N-acetyl-glycyl-L-lysine methyl ester, and two amino acid p-nitrophenyl esters, N-carbobenzyloxy-L-tyrosine-p-nitrophenyl ester and N alpha-carbobenzyloxy-L-lysine-p-nitrophenyl ester. A detailed kinetic analysis of the hydrolysis of N-Z-L-Tyr-ONp by C1r revealed that the enzymatic activity per microgram of protein decreased as the C1r concentration was increased. The loss of activity suggested that above 0.5 micron C1r was undergoing aggregation with a loss of active sites. Similarly, when C1r was titrated with the active site titrant p-nitrophenyl-P'-guanidinobenzoate the number of titratable sites per milligram of protein decreased with increasing protein concentration. The hydrolysis of N-Z-L-Tyr-ONp by C1r was inhibited by several synthetic inhibitors including phenylmethanesulfonylfluoride, p-amidinophenylmethanesulfonylfluoride, diisopropylfluorophosphate, and p-tosyl-L-lysine-chloromethyl ketone. However, the peptide esterase inhibitors Trasylol, hirudin, leupeptin, and C1 esterase inhibitor had no effect on the esterase activity of C1r.

A pharmacological and in vitro comparison of three oral cephalosporins

The pharmacology of cephradine, cephalexin and a new oral cephalosporin, cefaclor, has been compared in six volunteers. Cefaclor was absorbed rapidly and was cleared from the serum more rapidly than the other two agents. This was probably partially due to its instability in serum at body temperature, which was investigated. Against a wide range of common pathogens cefaclor was the more active oral cephalosporin. In particular the activity against Neisseria gonorrhoeae and Haemophilus influenzae was of interest.

Mezlocillin and azlocillin: an evaluation of two new beta-lactam antibiotics

Mezlocillin and azlocillin are broad spectrum penicillins for parenteral administration. In this study it was shown that they were very active against a wide range of pathogenic bacteria. Thirty-five patients were treated with mezlocillin, and 5 patients were treated with azlocillin (in combination with cefoxitin in 3 cases). The serum, bile and CSF levels of the drugs were measured. Both antibiotics would appear to be safe and efficacious in treating serious infections by sensitive pathogens. Infections caused by unknown pathogens could be treated by one of these agents in combination with a broad spectrum beta-lactamase stable cephalosporin or cephamycin.

LY127935, a novel oxa-beta-lactam: an in vitro comparison with other beta-lactam antibiotics

The in vitro activities of LY127935 (LY) were compared with those of other beta-lactam antibiotics. LY was highly active (minimal inhibitory concentration [MIC] range 0.06 to 0.25 micrograms/ml) against the common Enterobacteriaceae (including Providencia stuartiia, Enterobacter, and Serrati marcescens), 8 to 16 times more active than cefoxitin, cefuroxime, or cefazolin, and from one-half to one-eighth as active as cefotaxime (HR756). The activity of LY against Pseudomonas aeruginosa (with MICs of 4 and 64 micrograms/ml for 50 and 90% of test strains, respectively) was essentially similar to that of cefotaxime, but was only one-half as active as CGP 7174/E. LY, cefoxitin, and cefotaxime were essentially equally active against Bacteroides fragilis--each was more active than cefuroxime and cefazolin. Against Staphylococcus aureus, LY (50% MIC and 90% MIC of 4 and 16 micrograms/ml, respectively) was less active than cefotaxime, cefoxitin, or cefuroxime and one-eighth as active as cefazolin. The composition and pH of the culture medium had little effect on the activity of LY, although 7.2 appeared to be the optimum pH.

HR 756, a highly active cephalosporin: comparison with cefazolin and carbenicillin

HR 756, a new parenteral cephalosporin, was compared with cefazolin and carbenicillin for activity against a total of 264 strains of Pseudomonas aeruginosa, Escherichia coli, Klebsiella spp., Proteus mirabilis, Proteus spp. (indole positive), Enterobacter spp., Salmonella typhi, Serratia marcescens, Providencia stuartii, and Staphylococcus aureus. In every comparison, except that with the last organism, HR 756 was clearly more active than cefazolin and carbenicillin. All three compounds had similar activity against penicillin-susceptible staphylococci; against penicillin-resistant strains, HR 756 and cefazolin were equally active and superior to carbenicillin. HR 756 was compared with penicillin for activity against strains of Streptococcus pyogenes, Lancefield group D streptococci, and Neisseria gonorrhoeae; with ampicillin against Haemophilus influenzae; and with cefoxitin against Bacteriodes fragilis. HR 756 was clearly more active than the respective reference compounds in all of these comparisons, except those involving the streptococci. HR 756 and penicillin were essentially equally active against S. pyogenes; against Lancefield group D, penicillin was 32 times as active as HR 756. HR 756 not only compared favorably with the reference compounds with respect to relative activity, but also effected growth inhibition of essentially all test organisms (P. aeruginosa and group D streptococci excepted) at remarkably low concentrations ranging from 0.015 to 2.0 mug/ml. A series of seven transfers of selected strains of E. coli, Klebsiella spp., S. aureus, and P. aeruginosa through medium containing HR 756 led to emergence of strains with significant levels of resistance to the agent. Resistance to HR 756 was retained for at least seven transfers through plain medium.

Inhibition of four human serine proteases by substituted benzamidines

A series of substituted benzamidines has been examined for their inhibitory activity against the human serine proteases--trypsin, thrombin, plasmin, and C1s, a subunit of the first component of complement. The inhibition constants obtained for each enzyme were correlated with physical-chemical properties of the substituent group using the quantitative structure-activity relationship approach. This analysis indicated that plasmin and C1s are very similar in their interactions with substituted benzamidines. The binding of benzamidines in both enzymes was affected by electron donation from the substituent and its hydrophobicity. Thrombin-benzamidine interaction was affected only by the hydrophobicity of the substituent. Trypsin displayed a complex interaction with substituted benzamidines, and interaction was dependent on molar refractivity and molecular weight. Certain substituents deviated significantly from the interactions predicted by the analysis. These compounds, the (m- and p-amidinophenyl)pyruvic acids, when analyzed by computer modeling, suggested that direct interaction between the substituent and the enzyme surface is important in assessing the effect of substituent groups on inhibitory activity.

Comparison of the in vitro activity of Bay k 4999 and piperacillin, two new antipseudomonal broad-spectrum penicillins, with other beta-lactam drugs

Bay k 4999 and piperacillin, two new substituted ampicillins, were compared with other beta-lactam antibiotics, including carbenicillin, azlocillin, mezlocillin, benzylpenicillin, ampicillin, and cefoxitin, against a wide range of gram-positive and -negative organisms. Bay k 4999 and piperacillin were extremely active against Pseudomonas aeruginosa (50% inhibited by 2 mug/ml), being about 16-fold more active than carbenicillin. Bay k 4999 was the most active drug against Escherichia coli (50% inhibited by 0.5 mug/ml) and Klebsiella spp. (50% inhibited by 2 mug/ml). Piperacillin and Bay k 4999 were equally active against Proteus spp., and piperacillin had high activity against Bacteroides fragilis (50% inhibited by between 1 and 2 mug/ml).

Decreased spinal cord cGMP in murine (wobbler) spontaneous lower motor neuron degeneration

Of the secondary messengers, cyclic quanosine monophosphate, but not cyclic adenosine monophosphate, was reduced by 80% in the cervical spinal cord and by 56% in the cerebellum of clinically affected homozygote "wobbler" mice compared to sex- and age-matched litter-mate clinically unaffected control mice. A neurotransmitter, gamma aminobutyric acid, and high-energy intermediates, adenosine triphosphate and phosphocreatine, were not significantly different in affected or unaffected mice.

UK-18892, a new aminoglycoside: an in vitro study

UK-18892 is a new aminoglycoside antibiotic, a derivative of kanamycin A structurally related to amikacin. It was found to be active against a wide range of pathogenic bacteria, including many gentamicin-resistant strains. The spectrum and degree of activity of UK-18892 were similar to those of amikacin, and differences were relatively minor. UK-18892 was about twice as active as amikacin against gentamicin-susceptible strains of Pseudomonas aeruginosa. Both amikacin and UK-18892 were equally active against gentamicin-resistant strains of P. aeruginosa. There were no appreciable differences in the activity of UK-18892 and amikacin against Enterobacteriaceae and Staphylococcus aureus. Cross-resistance between these two antimicrobials was also apparent.

Activity of azlocillin and mezlocillin against gram-negative organisms: comparison with other penicillins

The activities of azlocillin and mezlocillin were compared with those of carbenicillin, ticarcillin, and pirbenicillin against a wide range of gram-negative organisms. The two new drugs were considerably more active than carbenicillin against Klebsiella species and Escherichia coli. Carbenicillin was twice as active against Proteus mirabilis as mezlocillin and four times as active as azlocillin. Against Pseudomonas aeruginosa, azlocillin was eight times as active as carbenicillin. Azlocillin and mezlocillin were twice as active as carbenicillin against Bacteroides fragilis, and these drugs showed a high degree of activity against Haemophilus influenzae and Neisseria gonorrhoeae.

In vitro study of clavulanic acid in combination with penicillin, amoxycillin, and carbenicillin

The activity of clavulanic acid alone and in combination with penicillin, amoxycillin, and carbenicillin was studied. Marked reductions in the minimum inhibitory concentrations (MICs) for a wide spectrum of beta-lactamase-producing clinical isolates were found. Of particular interest were the decreased MICs of penicillin for Bacteroides fragilis and beta-lactamase-producing strains of Neisseria gonorrhoea in the presence of the clavulanic acid. Beta-lactamase-producing strains of Escherichia coli, Klebsiella spp., and indole-negative Proteus also showed considerably increased susceptibility to amoxycillin in combination with clavulanic acid. Two beta-lactamase-producing strains of Pseudomonas aeruginosa remained resistant to carbenicillin in the presence of clavulanic acid.

Inhibition of C1s-induced vascular leakage in guinea pigs by substituted benzamidine and pyridinium compounds

A variety of benzamidine and pyridinium compounds were examined for their ability to inhibit irreversibly C1s-induced vascular leakage in guinea pig skin. Vascular leakage was compared with esterolysis of N-Z-L-Tyr-Np and catalysis of EAC42 formation by C1s. Vascular leakage correlated significantly better with esterolytic activity than with EAC42 formation. The presence of a sulfonyl fluoride moiety in the compounds is important in the inhibition of C1s-induced vascular leakage.

The activity of four antimicrobial agents. Including three nitroimidazole compounds, against Bacteroides sp

Forty strains of Bacteroides sp. were tested against three nitroimidazole compounds, metronidazole, tinidazole and nimorazole and the aminoglycosidic antibiotic spectinomycin. The effect of altering the inoculum and the presence of serum upon the minimum inhibitory concentration (MIC) was also noted. The three nitroimidazole compounds were all very active (average MIC = circa 0.25 mg/l). Tinidazole was twofold more active. The MIC of spectinomycin was 32 mg/l.

An areolar approach to reduction mammaplasty

The authors present a new technique for selected cases of reduction mammaplasty and correction of ptosis, based solely on a aureolar approach. The skin is undermined, the glandular contents reduced if required and a mastopexy carried out. The excess skin is not removed but adapts itself to the new size and shape of the gland.

The fine structure of the cervical spinal cord, ventral root and brachial nerves in the wobbler (wr) mouse

Much indirect evidence supports the prevailing concept that the wobbler mouse represents an inherited form of lower motor neuron degeneration, with resultant neurogenic muscular atrophy, due to an autosomal recessive gene (wr). This report, which emphasizes the fine structural changes in the wobbler mouse cervical spinal cord, ventral root and brachial nerves, both extends and modifies previously published data concerning the ultrastructural changes in this disorder. In addition to the more obvious neuronal cytoplasmic vacuolization known to occur, studies extended to a broader age range of wobbler mice have revealed neuronal alterations such as nonvacuolar dissolution of granular endoplasmic reticulum, proliferation of cytoplasmic microtubules and neurofilaments, proliferation of branched tubules resembling smooth endoplasmic reticulum, development of lipid droplets, and increased numbers of pleomorphic dense and lamellar cytoplasmic bodies. The spectrum of pathological changes in this murine form of motor neuron disease thus appears more complex and varied than has hitherto been appreciated, and may be relevant to the formulation of pathogenetic hypotheses.

Studies on a murine form of spontaneous lower motor neuron degeneration--the wobbler (wa) mouse

The wobbler (wr) mouse has been considered an animal model of spontaneous lower motor neuron degeneration which is inherited as an autosomal recessive trait. Previously available data are, however, also compatible with genetic factors playing a necessary though not exclusive role in the expression of the wobbler trait. The present report describes the results of chromosome analyses, electromyography and selected histochemical studies on wobbler mice, as well as studies exploring the possible participation of infectious agents, transneuronal effects, retrograde effects, aging, circulating toxins and immunologic factors in the pathogenesis of the wobbler disorder. The data obtained do not implicate any of these mechanisms in the pathogenesis of the wobbler trait and also indicate that the wobbler mouse is not a clinical variant of the recently described type C oncornavirus-induced murine paralytic disease.