Mild exercise expedites joint clearance and slows joint degradation in a joint instability model of osteoarthritis in male rats

OBJECTIVE

Exercise remains a hallmark treatment for post-traumatic osteoarthritis (PTOA) and may maintain joint homeostasis in part by clearing inflammatory cytokines, cells, and particles. It remains largely unknown whether exercise-induced joint clearance can provide therapeutic relief of PTOA. In this study, we hypothesized that exercise could slow the progression of preclinical PTOA in part by enhancing knee joint clearance.

DESIGN

Surgical medial meniscal transection was used to induce PTOA in 3-month-old male Lewis rats. A sham surgery was used as a control. Mild treadmill walking was introduced 3 weeks post-surgery and maintained to 6 weeks post-surgery. Gait and isometric muscle torque were measured at the study endpoint. Near-infrared imaging tracked how exercise altered lymphatic and venous knee joint clearance during discrete time points of PTOA progression.

RESULTS

Exercise mitigated joint degradation associated with PTOA by preserving glycosaminoglycan content and reducing osteophyte volume (effect size (95% Confidence Interval (CI)); 1.74 (0.71-2.26)). PTOA increased hind step widths (0.57 (0.18-0.95) cm), but exercise corrected this gait dysfunction (0.54 (0.16-0.93) cm), potentially indicating pain relief. Venous, but not lymphatic, clearance was quicker 1-, 3-, and 6-weeks post-surgery compared to baseline. The mild treadmill walking protocol expedited lymphatic clearance rate in moderate PTOA (3.39 (0.20-6.59) hrs), suggesting exercise may play a critical role in restoring joint homeostasis.

CONCLUSIONS

We conclude that mild exercise has the potential to slow disease progression in part by expediting joint clearance in moderate PTOA.

A feasibility study on the use of digital tomosynthesis with individually-acquired megavoltage portal images for target localization

PURPOSE

To determine the feasibility of using megavoltage (MV) images and digital tomosynthesis to determine the three dimensional (3D) localization of different objects.

MATERIALS AND METHODS

Different phantom geometries were imaged using an electronic portal imaging device and digital tomosynthesis was used to reconstruct tomograms. These were compared with corresponding computed tomography (CT) images.

RESULTS

While in-plane resolution of the tomograms was comparable as that of the CT images, definite out-of-plane (depth) localization was restricted to 5 mm.

CONCLUSION

The results confirm that it is possible to perform 3D localization of objects by using digital tomosynthesis for volumetric reconstructions from individually-acquired MV-quality portal images.

Long-term malaria prophylaxis with weekly mefloquine

The spread of chloroquine-resistant Plasmodium falciparum malaria has led to increased use of mefloquine prophylaxis by US Peace Corps volunteers in sub-Saharan Africa. We compared long-term mefloquine with other drug regimens for effectiveness and tolerance. The incidence of Plasmodium falciparum infections and of adverse reactions was compared in Peace Corps volunteers who took chloroquine weekly, mefloquine weekly, mefloquine every other week, or weekly chloroquine plus daily proguanil. Weekly mefloquine was 94% more effective than chloroquine (95% CI 86% to 97%), 86% more effective than chloroquine plus proguanil (95% CI 67% to 94%), and 82% more effective than prophylaxis with mefloquine when taken every other week (95% CI 68% to 90%). No serious adverse reactions were observed. Mild adverse events were equally frequent in mefloquine users and chloroquine users, and the frequency of these events declined with increasing duration of prophylaxis. Mefloquine is an effective and well-tolerated drug for prophylaxis of malaria by short-term and long-term travellers.

Perceptual reference frames and visual field asymmetry for verbal processing

Two experiments investigated the role of perceptual reference frames in producing visual field asymmetries for the recognition of consonant-vowel-consonant (CVC) nonsense syllables. In an upright stimulus display condition, both quantitative and qualitative visual field asymmetries replicated those obtained in earlier studies of CVC identification. When the stimulus displays were rotated 90 degrees clockwise or counterclockwise, there were no effects of presenting the CVC in relative LVF vs relative RVF stimulus locations. The contrast between results in the upright and rotated stimulus display conditions indicates that the LVF/RVF differences in the upright displays are attributable to the position of the CVC relative to the fovea, rather than relative to the perceptual reference frame. This finding is consistent with the interpretation that LVF/RVF differences in the upright condition are attributable to hemispheric differences in the processing of linguistic/phonetic information.