MR monitoring of focused ultrasound surgery in a breast tissue model in vivo

The objective of this study was to investigate MRI methods for monitoring focused ultrasound surgery (FUS) of breast tumors. To this end, the mammary glands of sheep were used as tissue model. The tissue was treated in vivo with numerous single sonications which covered extended target volumes by employing a scanning technique. The ultrasound focus position was controlled by online temperature mapping based on the temperature dependence of the relaxation time T(1). This approach proved to be reliable and offers thus an alternative to proton resonance frequency methods, whose application is hampered in fatty tissues. FUS-induced tissue changes were visible on T(2)- as well as on pre- and post-contrast T(1)-weighted images. According to our initial experience, noninvasive MRI-guided FUS of breast tumors is feasible.

Wrestling mats: are they a source of ringworm infections?

OBJECTIVE

To determine if the fungal molds (dermatophytes) responsible for causing ringworm could be isolated from a section of wrestling mat during the 1998-1999 season.

DESIGN AND SETTING

A 2-part study was conducted. The first phase involved a culture evaluation of material taken from wrestling mats at 8 local high schools. The second phase was a bench laboratory study to determine if the fungus and molds could be grown from a wrestling mat in an optimal setting.

SUBJECTS

We obtained material from areas of the practice mats of 8 high school wrestling teams at monthly intervals during the wrestling season. A 0.61-m (2-ft)x 0.31-m (1-ft) area of mat from 1 of the schools was used for the laboratory phase of the study.

MEASUREMENTS

We cultured samples taken from each school's wrestling mats for growth of dermatophytes and used a questionnaire to determine the mat-washing habits and policies of each school. Also, wrestlers from the 8 schools were screened weekly by the designated team physician and certified athletic trainer. Any suspicious lesions were cultured for fungi.

RESULTS

No dermatophytes were grown from the swab specimens taken at the 8 schools, and no dermatophytes were isolated from a section of mat evaluated in optimal laboratory conditions.

CONCLUSIONS

It is unlikely that wrestling mats are a source of ringworm infections in wrestlers.

Fluconazole for the prevention and treatment of tinea gladiatorum

BACKGROUND

Tinea gladiatorum is a common problem in competitive wrestling. It impacts on a wrestler's ability to compete. Several methods have been advocated to prevent these infections; however, no well-designed study of pharmacologic prophylaxis has been conducted.

METHODS

In a double blind placebo-controlled trial during the 1998 to 1999 regular wrestling season, wrestlers were randomized to receive 100 mg of fluconazole once weekly or placebo once weekly. Those not involved in the study were treated as a second control group. The effects of prophylaxis were also examined by assessing treatment of clinical infections with fluconazole 200 mg weekly for 4 weeks.

RESULTS

There was a significantly smaller incidence of infection in those given fluconazole (6%) than in those receiving placebo (22%) and those not involved in the prophylaxis phase (18%) (P<0.05). There was also a significant reduction in the total number of infections in the fluconazole group (P<0.05). Prophylaxis with fluconazole did not impact on the severity of disease, if contracted, when compared with the placebo prophylaxis participants who contracted tinea corporis. Of 21 wrestlers with tinea infections and positive cultures, 14 were able to have their isolates identified as Trichophyton tonsurans.

CONCLUSIONS

Fluconazole is effective and safe for primary prevention of tinea gladiatorum. We must now define when and in what population prophylaxis would be warranted.

Conditioned tolerance to drug-induced (poly I:C) natural killer cell activation: effects of drug-dosage and context-specificity parameters

Three experiments were conducted to evaluate the role of drug-dosage and stimulus-specificity parameters on the tolerance of drug-induced (poly I:C) natural killer (NK) cell activity. In the first experiment a protocol which provided mice with four weekly 20 micrograms/mouse ip injections of the immunostimulatory synthetic polynucleotide (poly I:C) following exposure to either a simple odor cue or a complex cue resulted in tolerance of NK cell activity. The identical protocol with a higher drug dose (50 micrograms/mouse) did not produce tolerance. In a second experiment, the stimulus specificity of tolerance was assessed by giving two groups of mice repeated signaled drug injections. For one of these groups the final poly I:C injection of the series was signaled, while for the other group it was not. Although both groups were tolerant relative to controls not previously exposed to the drug, indirect evidence of conditioning was obtained. Specifically, it was found that tolerance among mice receiving the signal on the test was such that they were not different from undrugged controls, while uncued mice had significantly higher levels of NK cell activity. The third experiment evaluated the role of stimulus specificity within an extinction paradigm. It was found that tolerance was reversed in mice provided with repeated nonreinforced reexposure to drug-signaling cues, while mice exposed to novel cues remained tolerant. These results further support the hypothesis that associative factors contribute to the tolerance of a drug-induced immune response.