Sensitivity of Citrobacter freundii and Citrobacter koseri to cephalosporins and penicillins

An examination of 99 field and reference strains of Citrobacter freundii showed 79% of them to be resistant to cephaloridine and sensitive to carbenicillin, while 96% of 45 field and reference strains of Citrobacter koseri examined were sensitive to cephaloridine and resistant to carbenicillin. Susceptibility tests with these two antibiotics are therefore useful in separating the two species of Citrobacter.

John Arthur Harland Hancock, 1923-1974

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Antibacterial activity of cefamandole, a new cephalosporin antibiotic, compared with that of cephaloridine, cephalothin, and cephalexin

The in vitro antibacterial activity of cefamandole, a new cephalosporin antibiotic, was compared with that of cephaloridine, cephalothin, and cephalexin against 1,213 strains of gram-positive and gram-negative bacteria recently isolated from clinical sources. The decreasing order of activity of the four agents against gram-positive cocci was cephaloridine, cephalothin, cefamandole, and cephalexin. However, cefamandole was the most active of the four against Haemophilus species and gram-negative bacilli susceptible to cephalosporins. It was also active against many strains resistant to the other cephalosporins, such as Enterobacter species and indole-positive Proteus species, but there was a marked inoculum effect with all of these organisms, and minimal bactericidal concentrations were usually considerably higher than minimal inhibitory concentrations. Cefamandole, like other cephalosporins, had no useful activity against Pseudomonas species.

Venereal disease problems and adolescent health

The current world-wide rise in venereal diseases among young people is deeply in terrelated with other facets of modern liv ing. Exploration of causative influences should lead to increased understanding and healthier patterns of living.

A Mechanism for the Origin of Specifically Oriented Textures in Development with Special Reference to Nitella Wall Texture

Many oriented growth phenomena, including the elongation of the Nitella internode, are based upon oriented or textured cell wall structure. In many cases the ordered textures are not present in the earliest stages of cell development but appear later. In Nitella lateral cell (leaf) development the first appearance of transverse wall texture (detected in polarized light) approximately coincides with a transverse stretching of the cell and its wall. This oriented stretching appears not to have its origin in a pre-existing texture but rather to be the result of a particular distribution of wall expansion rates. The relation between rates and oriented distortions is studied as a general phenomenon. The form these rate variations must take to provide longitudinal, transverse, or isotropic distortion is derived. Model devices made of rubber membranes, where expansion rate is varied by reinforcement of the rubber, generate distortions (textures in the rubber) of the type predicted. In the course of development it is possible that imbalances in expansion rate based on gradients (of metabolites, pH, light, etc.) bring on, through strain orientation, the initial alignment of originally randomly oriented fibrous ultrastructures, such as microfibrils of the cell wall or cytoplasmic microtubules.