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OBJECTIVE: To investigate the effects of an 8-week, 24-session weight-bearing physical conditioning program on disease signs and symptoms in children with chronic arthritis. METHODS: In a within-subjects, repeated measures design, 25 subjects, ages 8-17 years, with chronic polyarticular juvenile rheumatoid arthritis (JRA), were assessed at study entry, after an 8-week control period, and after an 8-week exercise period, for 1) disease status, based on joint count (JC) and articular severity index (ASI) (sum of scores for joint swelling, pain on motion, tenderness, and limitations of motion); 2) worst pain during the past week, using a 10-cm visual analog scale (VAS), and 3) aerobic endurance, using the 9-minute run-walk test of the Health Related Physical Fitness Test battery. The 60-minute conditioning program included warm-up (10 minutes), low-impact aerobics (25 minutes), strengthening (15 minutes), and cool-down and flexibility exercises (10 minutes). Subjects exercised twice a week at their rheumatology center and once a week at home, using a commercial exercise video-tape supplied by the investigator. RESULTS: Significant improvement was found in the ASI (Friedman analysis of variance [ANOVA]), JC, and 9-minute run-walk test (repeated measures ANOVA) from the pre- to post-exercise tests. Mean VAS pain scores decreased 16% from study entry to the post-exercise test. Statistically significant improvement (reliable change index > 1.96) occurred in 80% of subjects on the ASI and 72% on the JC. CONCLUSION: Children and adolescents with chronic polyarticular JRA can improve their aerobic endurance through participation in weight-bearing physical conditioning programs without disease exacerbation or increased pain, and may achieve decreased joint signs and symptoms through increased physical activity.

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Buffering extracellular pH at the site of a spinal cord crush-injury may stimulate axonal regeneration in rats (1; Guth et al., Exp. Neurol. 88: 44-55, 1985). We demonstrated in cultured astrocytes that acidic pH initiates a rapid increase in immunoreactivity for GFAP (GFAP-IR), a hallmark of reactive gliosis (2; Oh et al., Glia 13: 319-322, 1995). We extended these studies by investigating the effects of certain treatments on reactive gliosis developing in situ in a rat spinal cord injury model. A significant reactive gliosis was observed within 2 days of cord lesion in untreated crush or vehicle-treated, crush control animals as evidenced by increased GFAP-IR and hypertrophy of astrocytes. By contrast, infusion of Pipes buffer (pH 7.4) into the lesion site significantly reduced this increase. The increased GFAP-IR appeared to be linked to Ca2+ influx since infusion of a blocker of L-type calcium channels, nifedipine, reduced the ensuing reactive gliosis significantly. While Ca2+ modulates many signaling pathways within cells, its effect on reactive gliosis appeared to result from an activation of calpain I. Calpain inhibitor I, a selective inhibitor of mu-calpain, also significantly reduced reactive gliosis. However, calpain inhibitor II, a close structural analog which blocks m-calpain, had no salutary effect. We suggest, therefore, that the initial reactive gliosis seen in vivo may result from the activation of a neutral, Ca2+-dependent protease, calpain I, through calcium influx.

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Cerebral cortical lesions were produced using a stereotactic injection system in Sprague-Dawley rats randomly assigned to three groups: (1) needle lesioned and uninjected (Lesioned), (2) needle lesion and simultaneous local injection of 50 or 100 microliters 0.9% saline (L/Saline), and (3) needle lesion and simultaneous local injection of 50 or 100 microliters Verapamil-HCl (VHCL) (2.5 mg/ml (5 mM) Abbott Labs, Chicago, IL), a passive, L-type calcium channel blocker (L/VHCL). The lesioning induced expression of glial fibrillary acidic protein (GFAP), a type of intermediate filament protein expressed in reactive astrocytes, at the lesion site. There was a reduction in GFAP-like immunoreactivity (GFAP-IR) in the L/VHCL group versus the Lesioned and the L/Saline groups. There was a five-fold increase of GFAP-IR at 24 h post lesion in the L/Saline group, but no statistically significant increase seen in the Lesioned or L/VHCL groups at either volume. Pretreatment of the anti-GFAP with VHCL did not impair the antigen labeling. To determine whether differences in pHs, or volume could account for these findings, a second experiment was performed using pH-matched saline or VHCL in 10 microliters volume injected into contralateral hemispheres at the time of lesioning. There was an 80% reduction in GFAP-IR in the L/VHCL group at 72 h compared with the L/Saline group. These data suggest that VHCL may suppress the early increase of GFAP-IR in response to cortical lesion and that reducing transmembrane calcium flux through L-type calcium channels may be the mechanism involved.

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A young patient developed rhabdomyolysis after accidentally inhaling gasoline vapors. Although there had been no preexistent myopathy, the caffeine and halothane contracture test classified the patient as being malignant hyperthermia-susceptible (MHS). Abnormal contractures also occurred after exposure of muscle bundles to benzine (at 0.01%); in four control tests, benzine-induced contractures (at 0.1%) could be elicited in MHS, but not in normal, muscles. The complex composition of benzine seems to contain potentially hazardous agents that trigger MH.

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OBJECTIVE: To review the literature in the area of physical fitness and conditioning programs for individuals with chronic illnesses, and increase the awareness of the need to include fitness testing and conditioning programs in the therapeutic management of children and adolescents with chronic arthritis. METHODS: This article provides a review of original research reports, information from principal texts, and review articles related to physical fitness testing and training in children. RESULTS: Several factors limit the exercise capacity of children with chronic arthritis, and studies report that these children have lower aerobic endurance and muscle performance than their peers. Preliminary studies suggest that fitness testing is safe for most children with arthritis, and physical conditioning programs, which appear to benefit adults with arthritis and children with other chronic illnesses, may also benefit children with arthritis. Easily administered, inexpensive field tests of fitness are available. Guidelines for prescribing physical conditioning programs are provided. The risks and benefits of increased exercise are discussed. CONCLUSIONS: Assessment of exercise capacity and muscle function and individualized prescription of physical conditioning programs are indicated for children with chronic arthritis, soon after diagnosis.

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Children with juvenile rheumatoid arthritis (JRA) often exhibit fatigue and prolonged exercise recovery. Improved fitness through physical conditioning has not been a goal of standard medical or physical treatment regimens for JRA, and fitness levels of children with JRA have rarely been studied. We compared physical fitness in 20 6 to 11-year-old patients with polyarticular JRA with sex-, age-, and size-matched controls, using the Health Related Physical Fitness Test (HRPFT), a national, standardized, norm-referenced test. We correlated fitness scores with summary joint counts, and with an articular severity index (sum of joint swelling, tenderness, pain, and limited range for each child). The results showed that children with polyarticular JRA were less physically fit than normally active (noncompetitively athletic) children of the same sex, age, and size. There was no statistically significant relationship between increased joint counts, and/or disease severity scores, and reduced fitness scores. This suggests that physical fitness levels are less related to degree of "disease activity" than is often thought. We conclude that (1) a readily available, nationally standardized fitness test can be used to assess children with JRA: and (2) fitness levels and measures of disease activity do not correlate. We believe that multiple factors, perhaps including family, physician, and school concerns about potential disease exacerbation following exercise, may account for the low fitness levels observed in children with JRA.

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