Staphylococcal adhesion to collagen in intra-articular sepsis.

Ultrastructural studies of the cartilaginous articular surfaces of human and rabbit joints have shown that cartilage is the target substratum for adhesion by Staphylococcus aureus, leading to intra-articular sepsis. Transmission and scanning electron microscope studies demonstrated bacteria in intimate contact with acellular cartilage matrix surfaces, particularly with collagen fibres. Certain strains of Staphylococcus aureus used in these experiments reveal a high binding capacity to collagen that is derived from a cartilage matrix. These studies indicate that the pathogenesis of intra-articular sepsis is based on the ability of certain strains of staphylococci to bind preferentially to a cartilage matrix.

Ultrasonography of the shoulder. Static and dynamic imaging.

High-resolution, real-time ultrasonography is an effective diagnostic technique for evaluating rotator cuff movements and is useful in detecting aberrations that correlate with rotator cuff biomechanics and impingement syndrome.

Energization of glucose transport by Pseudomonas fluorescens.

We have measured the capacity of Pseudomonas fluorescens to transport the glucose analog 2-deoxy-d-glucose and the amino acids l-alanine and alpha-aminoisobutyric acid under conditions in which the cells could generate (i) both a membrane proton motive force and high-energy phosphate compounds, (ii) a proton motive force but not high-energy phosphate compounds, and (iii) neither a proton motive force nor high-energy phosphate compounds. This was done by depleting cells of adenosine triphosphate stores by treatment with sodium arsenate and then suspending them in a phosphate-free medium, where they could generate a proton motive force but not phosphate bond energy, or in a phosphate-containing medium, where they could generate both a proton motive force and phosphate bond energy. Inclusion of the proton-conducting ionophore carbonyl cyanide-m-chlorophenyl hydrazone under either condition precluded the generation of both a proton motive force and phosphate bond energy. The amino acids l-alanine and alpha-aminoisobutyric acid were transported independently of phosphate bond energy and required only a proton motive force. 2-Deoxy-d-glucose was transported only under conditions in which phosphate bond energy could be generated. These results are consistent with the findings of others that Pseudomonas aeruginosa produces an inducible shock-sensitive glucose-binding protein and conform to the generalization that binding protein-associated transport systems are energized by phosphate bond energy.