Essential roles of core starvation-stress response loci in carbon-starvation-inducible cross-resistance and hydrogen peroxide-inducible adaptive resistance to oxidative challenge in Salmonella typhimurium.

The starvation-stress response (SSR) of Salmonella typhimurium encompasses the physiological changes that occur upon starvation for an essential nutrient, e.g. C-source. A subset of SSR genes, known as core SSR genes, are required for the long-term starvation survival of the bacteria. Four core SSR loci have been identified in S. typhimurium: rpoS, stiA, stiB, and stiC. Here we report that in S. typhimurium C-starvation induced a greater and more sustainable cross-resistance to oxidative challenge (15 mM hydrogen peroxide (H2O2) for 40 min) than either N- or P-starvation. Of the four core SSR loci, only rpoS and stiC mutants exhibited a defective C-starvation-inducible cross-resistance to H2O2 challenge. Interestingly, (unadapted) log-phase S. typhimurium rpoS and stiA mutants were very sensitive to oxidative challenge. Based on this, we determined if these core SSR loci were important for H2O2 resistance developed during a 60 min adaptive exposure to 60 microM H2O2 (adapted cells). Both unadapted and adapted rpoS and stiA mutants were hypersensitive to a H2O2 challenge. In addition, a stiB mutant exhibited normal adaptive resistance for the first 20 mins of H2O2 challenge but then rapidly lost viability, declining to a level of about 1.5% of the wild-type strain. The results of these experiments indicate that: (i) the rpoS and stiC loci are essential for the development of C-starvation-inducible cross-resistance to oxidative challenge, and (ii) the rpoS, stiA, and, in a delayed effect, stiB loci are needed for H2O2-inducible adaptive resistance to oxidative challenge. Moreover, we found that both stiA and stiB are induced by a 60 microM H2O2 exposure, but only stiA was regulated (repressed) by (reduced form) OxyR.

Replacement of condylar process.

Three cases of replacement of the condylar process have been presented with their courses and the type of prosthesis that was chosen. Each case has a unique cause with different needs for the use of a prosthesis.

Dislocation of the condyle into the middle cranial fossa.

Surgical intervention by a preauricular approach appears to be the preferred treatment in this rare injury. It does not appear necessary or wise to disimpact the condyle as it presents more of a surgical risk and its presence in the cranial fossa seems to pose no neurological problems. The use of an interposing medium, placed after the teeth are secured in occlusion, appears to be definitely indicated to prevent ankylosis and, hopefully, to eliminate deviation of the mandible. A carved piece of Silastic, designed to conform to the recontoured roof of the glenoid fossa, has produced excellent results in cases of ankylosis; it served well in this case. Silastic has the advantages of being easy to carve, it may be attached to the rim of the fossa, and it is extremely nonirritating; it eventually becomes encased in a fibrous capsule.

Temporomandibular ankylosis secondary to rheumatoid arthritis. Report of a case.

A case of unilateral bony ankylosis of the temporomandibular joint secondary to rheumatoid arthritis is presented, and the surgical treatment and postoperative regime are suggested. It is believed that, with proper motivation of the patient, an adequate oral opening may be maintained.