Effect of Low Power Laser Irradiation on the Proliferation and Differentiation of PC12 Nerve Cells

OBJECTIVE: We examined the effect of low power laser irradiation (LPLI) on the proliferation and differentiation of PC12 nerve cells. METHOD: After seeding 4x10(5) PC12 nerve cells each in the 24 well-culture dishes, we cultured them for 6 days with RPMI1640 media. LPLI (650 nm, 5 mW, 5 sec) was applied for 1 day, 2 days and 3 days (1, 2 and 3-day-LPLI groups) consecutively. For the degree of proliferation of PC12 nerve cells, we compared the total cell number at 6th day after LPLI by MTT cell proliferation assay. For the degree of differentiation, we compared the length of neurite out-growth and the expression of RT97 at 6th day after adding nerve growth factor on each group. RESULTS: The total cell numbers were increased significantly after LPLI, but those increments were not significant among 1, 2, and 3-day-LPLI groups. The numbers of the differentiated PC12 nerve cells and the expressions of RT97 were diminished serially according to the number of days of LPLI. CONCLUSION: We conclude that LPLI increased the proliferation and decreased the differentiation of PC12 nerve cells. We could suggest that single or short-term use of LPLI on the injured nerve should be helpful for enhancing the neural regeneration in vivo.

Effect of Interferential Current Therapy of Swing Pattern Frequency Alteration on RIII Nociceptive Reflex

OBJECTIVE: The purpose of this study was to evaluate the effect of interferential current therapy (IFT) of swing pattern frequency alteration on the RIII nociceptive reflex. METHOD: Ten healthy volunteers received IFT of both constant (100 Hz) and swing (20~100 Hz) pattern frequency. Before and after the IFT application RIII nociceptive reflex was evoked by stimulation of sural nerve and recording at biceps femoris muscle. Twenty nine patients with low back pain were treated with IFT of constant or swing pattern frequency and degrees of pain relief were evaluated by Visual Analogue Scale (VAS) and Present Pain Intensity (PPI). RESULTS: The threshold of RIII reflex was increased immediately after both constant and swing frequency, but the increased threshold was lasted for 15 minutes only after swing pattern frequency alteration. Pain relieving effect of IFT evaluated by PPI was also lasted for 15 minutes only after swing frequency alteration. CONCLUSION: These results suggest that IFT of swing pattern frequency alteration had longer lasting effect on the inhibition of RIII nociceptive reflex and the relief of pain than that of constant frequency.

Expression of Caveolin-3 in the Muscle Cell and Tissue

OBJECTIVE: Caveolae are the microdomain of the plasma membrane that have been implicated in signal transduction and caveolin is a principal component of the caveolae. Caveolin-3, a family of caveolin related protein, is expressed only in muscle tissue. Here we examined the expression of caveolin-3 in the course of myobalst differentiation and within the muscle tissue. METHOD: L6 cell, rat skeletal myoblast, was cultured in the low mitogen medium and caveolin-3 expression was observed both by immunocytochemistry and western blot analysis. Localization of caveolin-3 within the muscle tissue was investigated and compared to that of dystrophin. RESULTS: While caveolin-3 was not expressed in the proliferating myolast, caveolin-3 was expressed in the differentiated myoblast. Caveolin-3 and dystrophin were co-expressed in the membrane of muscle tissue and integrated density of caveolin-3 was elevated in the area of muscle injury. In the Duchenne muscular dystrophy, caveolin-3 was expressed in the membrane of muscle tissue, but dystrophin was not. CONCLUSION: Caveolin-3 was induced during the myobalst differentiation and its expression was increased during the muscle regeneration. Caveolin-3 was physically associated with dystrophin as a complex, but not absolutely required for the biogenesis of dystrophin complex.

Correlation of Periventricular Leukomalacia on the Brain MRI and the Denver II and Capute Developmental Test

OBJECTIVE: This study was designed to evaluate the correlation of periventricular leukomalacia (PVL) on brain MRI and Denver II and Capute developmental test. METHOD: Thirty children with PVL on brain MRI showing delayed development were included. The severity of PVL was graded as localized/generalized lesion in three fields; periventricular hyperintensity in T2 weighted image (PVHI in T2WI), reduced volume of cerebral white matter (RV of CWM), ventriculomegaly with periventricular wall irregula rity (VM with PVWI). Development quotients were obtained by Denver II and Capute test, and assessed according to the severity of PVL. RESULTS: Although language, fine motor-adaptive, personal- social scale of Denver II and cognitive-adaptive and clinical linguistic and auditory milestone of Capute test had little correlation with severity of PVL, gross motor developmental scale assessed by Denver II had a certain degree of correlation with severity of PVL which was not significant statistically. The gross motor developmental scale of the nineteen preterm births had a significant correlation with VM with PVWI, but the other developmental scales still had no significant correlation with PVL. CONCLUSION: As for the children with delayed development the degree of motor development was a significant predictor of the PVL on brain MRI, but those of language and cognitive development were not.