The in-vitro activities of enoxacin and ofloxacin compared with that of ciprofloxacin

The in-vitro activities of enoxacin and ofloxacin were compared with that of the other new 4-quinolone, ciprofloxacin. All three compounds were highly active against Enterobacteriaceae, Haemophilus influenzae and Neisseria gonorrhoeae (MICs mostly less than 1 mg/l). The other Gram-negative aerobes tested were in general less susceptible, though for Acinetobacter and Pseudomonas species (including aeruginosa) MICs seldom exceeded 8 mg/l. Ofloxacin and ciprofloxacin were more active against Gardnerella vaginalis (MICs 0.5-2 mg/l) than was enoxacin (MICs 8-32 mg/l). Staphylococci were susceptible to ofloxacin (MICs 0.12-1 mg/l) and enoxacin (MICs 0.5-2 mg/l) as well as to ciprofloxacin. Streptococci also were mostly sensitive to the compounds though the MICs of enoxacin (4-64 mg/l) were noticeably higher than those of ofloxacin (1-4 mg/l). Anaerobes were in general susceptible though, as with streptococci, ofloxacin, with activity similar to that of ciprofloxacin, was more active than enoxacin. Variants of Enterobacteriaceae with reduced susceptibility were readily selected in the laboratory with either enoxacin or ofloxacin as the selective agent. The MICs of all the 4-quinolones were usually increased four- to 16-fold for these strains; they could therefore be regarded as remaining susceptible to the newer compounds.

Excitatory amino acid-induced responses of frog motoneurones bathed in low Na+ media: an intracellular study

Motoneurones of the frog spinal cord slice preparation were impaled with microelectrodes and superfused at 7 degrees C with the excitatory amino acids glutamate, quisqualate or N-methyl-D-aspartate. The role of Na+ in the action of these amino acids was studied by comparing amplitude matched depolarizations obtained in control Ringer solution with the responses recorded from the same cells after replacing (86-100%) Na+ by choline or glucosamine. Effective replacement of extracellular Na+ proved to be a rather slow process requiring 30-60 min. In glucosamine solution depolarizations evoked by glutamate, N-methyl-D-aspartate or quisqualate were abolished or strongly reduced with recovery following return to control Ringer. In choline solution, glutamate and N-methyl-D-aspartate effects were blocked whereas the quisqualate response was surprisingly unaffected. Mn2+ (2 mM) added to choline solution strongly diminished the action of quisqualate. These results suggest that Na+ was important in mediating amino acid responses and that quisqualate activated an additional conductance mechanism (perhaps to Ca2+) unmasked only in choline-containing solution.

Effective oral treatment of severe Paget's disease of bone with APD (3-amino-1-hydroxypropylidene-1,1-bisphosphonate); a comparison with combined calcitonin + EHDP (1-hydroxyethylidene-1,1-bisphosphonate)

Ten patients with severe Paget's disease of bone and serum alkaline phosphatase (sAP) greater than 900 IU/l were treated for six months with the oral diphosphonate APD, (3-amino-1-hydroxypropylidene-1, 1-bisphosphonate). By the end of the treatment period there was a reduction in the log mean urine hydroxyproline (uHP) and the log mean sAP of 92% and 87% respectively. In four patients both sAP and uHP fell to within the normal range and remained normal for at least six months after therapy was stopped. Bone scintigraphy showed a fall in 99mTc-MDP uptake in sites of active Paget's disease in all patients and histomorphometry showed no increase in osteoid. Repair of radiological osteolytic lesions was observed in 6/6 patients and progression of tibial osteolytic wedges was arrested in 5/5 patients and reversed in four. This improvement persisted six months after completion of therapy but further wedge progression occurred in one patient whose urine HP remained elevated. There were no serious effects though five patients complained of nausea. The clinical and biochemical responses to APD were equivalent to those observed in the same patients during a previous six month course of combined therapy with human calcitonin (CT) + EHDP except that there was additional biochemical and radiological evidence of bone healing. This study confirms PAD as an effective treatment of severe Paget's disease of bone.

Studies toward spasticity suppression with high frequency electrical stimulation

A technique employing high frequency stimulation of the muscle nerve is investigated as a potential treatment procedure for temporary and longterm suppression of spasticity. Animal experiments show that reversible inhibition of up to 95% of the maximal muscle force is possible with optimal stimulation frequency of 600 pulses per second. The data indicate that the possible blockade of neuromuscular activity is due to interruption of action potential transmission across the end plates or inhibition of binding sites due to Ca+ depletion.

External control of rate, recruitment, synergy and feedback in paralyzed extremities

An electrical stimulation technique is presented that provides external control of the movement processes by integrating them in a multi-loop electronic control system approximating the normal neuromuscular system.

Stromal invasion in endometrial adenocarcinoma

The ability to predict myometrial invasion by endometrial adenocarcinoma is useful for preoperative treatment purposes. The presence of stromal invasion is one possible method of predicting myometrial invasion, but criteria for the presence of stromal invasion have been lacking. Recently, criteria for its detection were proposed. We evaluated the validity of the proposed criteria in two conditions: (1) atypical hyperplasia (119 cases) and (2) endometrial adenocarcinoma Stage I, grade 1 (83 cases). Adenocarcinoma without stromal invasion according to the criteria of Kurman and Norris was present in 43 cases and adenocarcinoma with stromal invasion was present in 40 cases. This series demonstrated the ability of prehysterectomy endometrial sampling to predict the probability of myometrial penetration. In addition, none of our patients without stromal invasion in the resected uterus had myometrial penetration and no metastases have occurred. In those showing stromal invasion in the excised uterus, the myometrium was invaded in 34 of 51 cases (67%). Since myometrial penetration was not present when there was no stromal invasion in the resected uterus, stromal invasion deserves further evaluation and should be considered in future classification of endometrial adenocarcinoma.

Microinvasive squamous carcinoma of the vulva: present status and reassessment

A retrospective analysis of 24 patients with early invasive squamous carcinoma was performed. No nodal metastases were noted in these patients. Based on a review of the literature, no absolute definition of microinvasive carcinoma could be formulated, but a treatment outline has been formulated based on depth of invasion for Stage I lesions.

The in-vitro activity of ciprofloxacin compared with that of norfloxacin and nalidixic acid

The in-vitro activity of ciprofloxacin , a new 4-quinolone, was compared with that of norfloxacin and nalidixic acid against recent clinical isolates of medically important bacteria. Overall, ciprofloxacin and norfloxacin had similar spectra of activity, but ciprofloxacin had somewhat greater intrinsic activity against most organisms. Minimum inhibitory concentrations (MIC) were in the range 0.004-4 mg/l for Enterobacteriaceae, 0.016-2 mg/l for Pseudomonas spp., 0.004-1 mg/l for Acinetobacter, 0.004-0.016 mg/l for Haemophilus influenzae, 0.001-0.004 for gonococci, 0.004-0.03 mg/l for Cmpylobacter , 0.12-2 mg/l for staphylococci, 0.25-4 mg/l for streptococci, 1-32 mg/l for the Bacteroides fragilis group and mostly in the range 0.25-8 mg/l for other obligate anaerobes. Resistant variants could be selected readily in vitro by culture on any of the three compounds investigated. However, while the MICs of nalidixic acid were high for these variants those of ciprofloxacin and norfloxacin were much lower.

Neutropenic enterocolitis due to Clostridium septicum infection

Three cases of neutropenic enterocolitis are described. This unusual condition occurs almost exclusively in neutropenic patients and has a fulminating course which is almost invariably fatal without surgical intervention. The lesion is centered on the caecum and hitherto its pathogenesis has been unclear, partly because most studies have been performed on material obtained at necropsy. In these three patients, all of whom were treated surgically, Clostridium septicum was identified by specific immunofluorescence in the bowel wall of the resected specimens. Two patients also had C septicum septicaemia. Various forms of mucosal damage can be identified which predispose towards invasion of the bowel wall by this organism. These cases provide further confirmation of a primary role for C septicum in the pathogenesis of neutropenic enterocolitis.

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.

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.

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.

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.