To determine whether fiber type-specific expression of heat shock protein (HSP, or stress protein) occurs in unstressed rat skeletal muscle, the medial gastrocnemius of adult female Sprague-Dawley rats was subjected to immunohistochemical analysis. Antibodies against 5 types of anti-myosin heavy chain (MHC) were used to classify the type of fibers, and 2 types of anti-HSP antibodies were employed to analyze the fiber type-specific expression.
Serial cross-sections of 10 μm thick cut by a cryostat were incubated with primary anti-MHC or anti-HSP 60 and 72 antibodies, followed by biotinylated secondary anti-mouse antibodies, and avidin-biotin complex solution. A peroxidase DAB substrate kit (Vector SK-4100) or BCIP/NBT solution was used to visualize the immunoreaction of each fiber type.
By using the 5 types of anti-MHC antibodies, fibers were classified into 4 types : slow-type I, fasttypes IIA, IIX, and IIB. Anti-HSP 72 antibody reacted with many, but not all, type I and IIA fibers, whereas anti-HSP 60 antibody reacted specifically with type I fibers. Neither type IIX nor IIB fibers showed immunoreactivity with anti-HSP 60 or 72 antibodies. These results suggest that the expression of HSP 60 protein is related to that of type I MHC, and that the expression of HSP 72 protein may be related to that of types I and ha MHC, in unstressed rat skeletal muscle.

The expression levels of heat shock proteins after heat stress on rat slow soleus and fast plantaris muscles were examined and compared during a recovery period following 1 h of heat stress. The left hindlimbs of adult male Wistar rats (n=15) were carefully inserted into a stainless steel can and subjected to heat stress for 1 h by raising the air temperature inside the steel can to 54-58t with a flexible heater so as to bring the muscle temperature up to 42°C. The muscles of the contralateral right hindlimb served as the control. The expression levels of HSP 60, HSP 72, and HSC 73 were analyzed by Western blotting after 0, 2, and 4 h of recovery following 1 h of heat stress. In the soleus muscle, all of the HSP levels analyzed were significantly increased during 0-4 h of recovery. On the other hand, heat stress had no effect on the expression levels of HSPs, except HSP 60, in the plantaris muscle during recovery after 1 h of heat stress. These results suggest that the slow soleus muscle has a higher ablility to respond quickly to heat stress than the fast plantaris muscle.

STUDY DESIGN: Retrospective cohort study (level of evidence: 4).PURPOSE: To demonstrate the effects of balloon kyphoplasty (BKP) on prevention of kyphosis progression.OVERVIEW OF LITERATURE: Kyphoplasty can correct local kyphosis (fractured vertebra), but its efficacy is attenuated by adjacent fracture and/or disc height reduction with endplate damage. With these attenuating factors incorporated, a comparison between BKP and conservative treatment is necessary to verify the effect of BKP on kyphosis correction.METHODS: This study retrospectively analyzed 129 patients treated conservatively and 95 treated with BKP in our institution. The rate of new adjacent fracture occurrence was determined using Kaplan–Meier analysis. We examined the progression of local kyphosis in patients who underwent lateral X-ray after 1 year. Local kyphosis was measured as an angle between higher end plate of the vertebra above and lower end plate of the vertebra below the fractured vertebra. The comparison included 45 patients treated conservatively and 58 treated with BKP.RESULTS: The incidence of new adjacent fracture at 1 year was 7.3% in the conservative treatment group and 23.2% in the BKP group (p<0.001), while the progression of local kyphosis at 1 year was 5.7°±4.7° and 3.2°±4.6°, respectively (p=0.01). Relative to conservative treatment, local kyphosis did not progress after BKP, despite the higher incidence of adjacent fracture. Local kyphosis progressed in cases with adjacent fracture compared with those without adjacent fracture (6.0°±4.3° vs. 2.1°±4.3°, p=0.003), and fractured vertebral instability was found to be a risk factor for adjacent fracture in BKP.CONCLUSIONS: Compared with the conservative treatment, BKP suppressed the progression of local kyphosis. However, an adjacent fracture attenuated the BKP correction and was more frequently seen in patients with unstable vertebral fractures.
Cohort Studies ; Humans ; Incidence ; Kyphoplasty ; Kyphosis ; Retrospective Studies ; Risk Factors ; Spine