Tero A.H. Järvinen

Muscle Injuries Biology and Treatment

Muscle injuries are one of the most common traumas occurring in sports. Despite their clinical importance, few clinical studies exist on the treatment of these traumas. Thus, the current treatment principles of muscle injuries have either been derived from experimental studies or been tested only empirically. Although nonoperative treatment results in good functional outcomes in the majority of athletes with muscle injuries, the consequences of failed treatment can be very dramatic, possibly postponing an athletes return to sports for weeks or even months. Moreover, the recognition of some basic principles of skeletal muscle regeneration and healing processes can considerably help in both avoiding the imminent dangers and accelerating the return to competition. Accordingly, in this review, the authors have summarized the prevailing understanding on the biology of muscle regeneration. Furthermore, they have reviewed the existing data on the different treatment modalities (such as medication, therapeutic ultrasound, physical therapy) thought to influence the healing of injured skeletal muscle. In the end, they extend these findings to clinical practice in an attempt to propose an evidence-based approach for the diagnosis and optimal treatment of skeletal muscle injuries.

Amplification and Deletion of Topoisomerase IIα Associate with ErbB-2 Amplification and Affect Sensitivity to Topoisomerase II Inhibitor Doxorubicin in Breast Cancer

Topoisomerase IIalpha (topoIIalpha) is a key enzyme in DNA replication and a molecular target for many anti-cancer drugs called topoII inhibitors. The topoIIalpha gene is located at chromosome band 17q12-q21, close to the ErbB-2 oncogene (HER-2/neu), which is the most commonly amplified oncogene in breast cancer. Because of the physical proximity to ErbB-2, copy number aberrations may also occur in the topoIIalpha gene. These topoIIalpha gene copy number aberrations may be related to the altered chemosensitivity to topoII inhibitors that breast cancers with ErbB-2 amplification are known to have. We used fluorescence in situ hybridization to study copy number aberrations of both topoIIalpha and ErbB-2 in nine breast cancer cell lines and in 97 clinical breast tumors, which were selected for the study according to their ErbB-2 status by Southern blotting. TopoIIalpha-protein expression was studied with Western blot and sensitivity to doxorubicin (a topoII inhibitor) with a 96-well clonogenic in vitro assay. Two of the five cell lines with ErbB-2 gene amplification (SK-BR-3 and UACC-812) showed amplification of topoIIalpha. In MDA-361 cells, ErbB-2 amplification (14 copies/cell) was associated with a physical deletion of topoIIalpha (four copies of chromosome 17 centromere and two copies of topoIIalpha). The topoIIalpha amplification in UACC-812 cells was associated with 5.9-fold-increased topoIIalpha protein expression and 2.5-fold-increased sensitivity to the topoII inhibitor, doxorubicin, whereas the deletion in MDA-361 leads to decreased protein expression (45% of control) and a 2.4-fold-increased chemoresistance in vitro. Of 57 ErbB-2-amplified primary breast carcinomas, 25 (44%) showed ErbB-2-topoIIalpha coamplification and 24 (42%) showed a physical deletion of the topoIIalpha gene. No topoIIalpha copy number aberrations were found in 40 primary tumors without ErbB-2 amplification. TopoIIalpha gene amplification and deletion are common in ErbB-2-amplified breast cancer and are associated with increased or decreased sensitivity to topoII inhibitors in vitro, respectively. These findings may explain the altered chemosensitivity to topoII inhibitors reported in ErbB-2-amplified breast cancers.

Effect of a vibration exposure on muscular performance and body balance. Randomized cross-over study

This randomized cross‐over study was designed to investigate the effects of a 4‐min vibration bout on muscle performance and body balance in young, healthy subjects. Sixteen volunteers (eight men, eight women, age 24–33 years) underwent both the 4‐min vibration‐ and sham‐interventions in a randomized order on different days. Six performance tests (stability platform, grip strength, isometric extension strength of lower extremities, tandem‐walk, vertical jump and shuttle run) were performed 10 min before (baseline), and 2 and 60 min after the intervention. The effect of vibration on the surface electromyography (EMG) of soleus, gastrocnemius and vastus lateralis muscles was also investigated. The vibration‐loading, based on a tilting platform, induced a transient (significant at the 2‐min test) 2·5% net benefit in the jump height (P=0·019), 3·2% benefit in the isometric extension strength of lower extremities (P=0·020) and 15·7% improvement in the body balance (P=0·049). In the other 2‐min or in the 60‐min tests, there were no statistically significant differences between the vibration‐ and sham‐interventions. Decreased mean power frequency in EMG of all muscles during the vibration indicated evolving muscle fatigue, while the root mean square voltage of EMG signal increased in calf muscles. We have shown in this study that a single bout of whole body vibration transiently improves muscle performance of lower extremities and body balance in young healthy adults.

Estrogen Receptor β Is Coexpressed with ERα and PR and Associated with Nodal Status, Grade, and Proliferation Rate in Breast Cancer

The role of estrogen (ER) and progesterone receptors (PR) in breast cancer is well established. Identification of the second human estrogen receptor, the estrogen receptor β (ERβ), prompted us to evaluate its role in breast cancer. We studied the expression of ERβ by immunohistochemistry and mRNA in situ hybridization in 92 primary breast cancers and studied its association with ERα, PR, and various other clinicopathological factors. Sixty percent of tumors were defined as ERβ-positive (nuclear staining in >20% of the cancer cells). Normal ductal epithelium and 5 of 7 intraductal cancers were also found to express ERβ. Three-fourths of the ERα- and PR-positive tumors were positive for ERβ, whereas ERα and PR were positive in 87% and 67. of ERβ-positive tumors, respectively. ERβ was associated with negative axillary node status ( P P = 0.0003), low S-phase fraction ( P = 0.0003), and premenopausal status ( P = 0.04). In conclusion, the coexpression of ERβ with ERα and PR as well as its association with the other indicators of low biological aggressiveness of breast cancer suggest that ERβ-positive tumors are likely to respond to hormonal therapy. The independent predictive value of ERβ remains to be established.

Effect of 8‐Month Vertical Whole Body Vibration on Bone, Muscle Performance, and Body Balance: A Randomized Controlled Study

Recent animal studies have given evidence that vibration loading may be an efficient and safe way to improve mass and mechanical competence of bone, thus providing great potential for preventing and treating osteoporosis. Randomized controlled trials on the safety and efficacy of the vibration on human skeleton are, however, lacking. This randomized controlled intervention trial was designed to assess the effects of an 8‐month whole body vibration intervention on bone, muscular performance, and body balance in young and healthy adults. Fifty‐six volunteers (21 men and 35 women; age, 19‐38 years) were randomly assigned to the vibration group or control group. The vibration intervention consisted of an 8‐month whole body vibration (4 min/day, 3‐5 times per week). During the 4‐minute vibration program, the platform oscillated in an ascending order from 25 to 45 Hz, corresponding to estimated maximum vertical accelerations from 2g to 8g. Mass, structure, and estimated strength of bone at the distal tibia and tibial shaft were assessed by peripheral quantitative computed tomography (pQCT) at baseline and at 8 months. Bone mineral content was measured at the lumbar spine, femoral neck, trochanter, calcaneus, and distal radius using DXA at baseline and after the 8‐month intervention. Serum markers of bone turnover were determined at baseline and 3, 6, and 8 months. Five performance tests (vertical jump, isometric extension strength of the lower extremities, grip strength, shuttle run, and postural sway) were performed at baseline and after the 8‐month intervention. The 8‐month vibration intervention succeeded well and was safe to perform but had no effect on mass, structure, or estimated strength of bone at any skeletal site. Serum markers of bone turnover did not change during the vibration intervention. However, at 8 months, a 7.8% net benefit in the vertical jump height was observed in the vibration group (95% CI, 2.8‐13.1%; p = 0.003). On the other performance and balance tests, the vibration intervention had no effect. In conclusion, the studied whole body vibration program had no effect on bones of young, healthy adults, but instead, increased vertical jump height. Future human studies are needed before clinical recommendations for vibration exercise.

Characterization of topoisomerase IIα gene amplification and deletion in breast cancer

Topoisomerase IIα (TOP2A) is a key enzyme in DNA replication and a molecular target for many important anticancer drugs. TOP2A is amplified or deleted together with amplification of the closely located ERBB2/HER‐2/neu oncogene in breast cancer. We characterized the copy number aberrations of TOP2A and ERBB2 in 136 primary breast tumors by FISH. Among the 70 primary tumors with ERBB2 amplification, amplification of TOP2A was found in 29 (41%); 30 tumors (43%) showed a physical deletion of TOP2A; and the copy number for TOP2A was not altered in 11 tumors with ERBB2 amplification (16%). No TOP2A gene aberrations were identified in 65 primary tumors without ERBB2 amplification. Fiber FISH revealed that simultaneously amplified ERBB2 and TOP2A were not present in the same amplicon, because repetitive tandem repeat‐like signals of ERBB2 and TOP2A were in separate DNA fibers. The deletion of TOP2A (seen in the MDA‐361 cell line and in 31 primary tumors) was interstitial, spanning less than two megabases of DNA. Mean copy numbers of TOP2A (2.4 ± 0.6 for TOP2A vs. 4.9 ± 1.1 for chromosome 17 centromere) suggest that the deletion of TOP2A occurs before polyploidization of the genome. Eight primary tumors with high‐level ERBB2 amplification showed a new type of intratumoral heterogeneity; two different cell clones with either high‐level amplification or deletion of TOP2A were found adjacent to each other in the same tumor. These results indicate that amplification of the ERBB2 oncogene is followed by complex secondary genetic aberrations, which lead to amplification or deletion of the TOP2A gene in a majority of tumors. Genes Chromosomes Cancer 26:142–150, 1999.

Organization and distribution of intramuscular connective tissue in normal and immobilized skeletal muscles

Collagen fiber network is a major contributor to the coherence and tensile strength of normal skeletal muscle. Despite the well-recognized importance of the intramuscular connective tissue to the normal integrity and function of the skeletal muscle, the specific architecture including the location and three-dimensional orientation of the intramuscular connective tissue within the muscle tissue is poorly described. The structure of the intramuscular connective tissue was studied by immunohistochemistry, polarization microscopy (the crimp length and angle of the collagen fibers) and scanning electron microscope (SEM) in rat skeletal muscles (gastrocnemius, soleus and tibialis anterior) in normal situation and after 3 weeks of disuse (immobilization). Three separate networks of collagen fibers were distinguished by SEM in the normal endomysium; fibers running longitudinally on the surface of the muscle fibers (the main collagen orientation), fibers running perpendicularly to the long axis of the muscle fibers and having contacts with adjacent muscle fibers, and fibers attached to the intramuscular nerves and arteries. Similarly, the SEM analysis also disclosed three distinct collagen fiber networks running in different directions in the perimysium, but, contrary to the endomysium, the main fiber orientation could not be established. Immobilization resulted in a marked increase in the endo- and perimysial connective tissue, the majority of the increased endomysial collagen being deposited directly on the sarcolemma of the muscle cells. Immobilization also resulted in substantial increase in the number of perpendicularly oriented collagen fibers with contacts to two adjacent muscle fibers in the endomysium. Further, immobilization clearly disturbed the normal structure of the endomysium making it impossible to distinguish the various networks of fibers from each other. In the perimysium, immobilization-induced changes were similar, the number of longitudinally oriented collagen fibers was increased, the connective tissue was very dense, the number of irregularly oriented collagen fibers was markedly increased, and consequently, the different networks of collagen fibers could not be distinguished from each other. Of the three studied intact muscles, the crimp angle of the collagen fibers was lowest in the soleus and highest in the gastrocnemius muscle, and the crimp angle decreased over 10% in all muscles after the immobilization-period. Altogether, the above described quantitative and qualitative changes in the intramuscular connective tissue are likely to contribute to the deteriorated function and biomechanical properties of the immobilized skeletal muscle.

Achilles tendon injuries.

The Achilles tendon is the strongest tendon in the human body. Because most Achilles tendon injuries take place in sports and there has been an common upsurge in sporting activities, the number and incidence of the Achilles tendon overuse injuries and complete ruptures have increased in the industrialized countries during the last decades. The most common clinical diagnosis of Achilles overuse injuries is tendinopathy, which is characterized by a combination of pain and swelling in the Achilles tendon accompanied by impaired ability to perform strenuous activities. Most patients with Achilles tendon injury respond favorably to conservative treatment and only those who fail to respond to carefully followed nonoperative treatment should undergo surgery for repair. A complete rupture of the Achilles tendon usually occurs in sports that require jumping, running, and quick turns. Although histopathologic studies have shown that ruptured Achilles tendons include clear degenerative changes before the rupture, many of the Achilles tendon ruptures occur suddenly without any preceding signs or symptoms. Neither conservative nor operative treatment is a treatment of choice for the ruptured Achilles tendon. It is generally accepted that surgery should be performed on ruptured Achilles tendons in young, physically active patients and in those patients for whom the diagnosis or the treatment of the rupture has been delayed, whereas the results of conservative treatment are an acceptable outcome in older patients with sedentary lifestyles. Many important issues still remain unanswered concerning the cause, pathogenesis, diagnosis, and management of the Achilles tendon disorders. Only when these issues have been solved by well-controlled studies can tailored treatment protocols be created.

Predictive value of topoisomerase IIalpha and other prognostic factors for epirubicin chemotherapy in advanced breast cancer.

Although cytotoxic chemotherapy is widely used in advanced breast cancer, there are no powerful predictors for the therapy response. Because topoisomerase IIalpha (Topo IIalpha) is the molecular target for the anthracycline class of anti-cancer drugs, we compared the immunocytochemical assay of Topo IIalpha with other biomarkers in the prediction of clinical response to Topo II inhibitor chemotherapy. Fifty-five patients with advanced breast cancer were treated with a single cytotoxic drug, Topo II-inhibitor, epirubicin (30 mg m(-2) weekly up to 1000 mg m(-2)), as first line cytotoxic chemotherapy. Objective response to treatment was analysed according to UICC criteria. The predictive value of Topo IIalpha expression, c-erbB2 oncoprotein, p53 tumour-suppressor protein, oestrogen (ER) and progesterone receptor (PR), S-phase fraction and DNA ploidy were analysed from representative formalin-fixed paraffin-embedded primary tumour samples. The proportion of Topo IIalpha-positive cells (Topo IIalpha index) failed to predict response to epirubicin therapy. Mean Topo IIalpha scores in 29 responding patients were similar when compared with those with no change in disease progression (n = 13) and those with progressive disease (n = 13) (14.9% +/- 11.4% vs 15.5% +/- 7.6% vs 17.3% +/- 13.2%, not significant). Among the other biomarkers tested, overexpression of c-erbB2 oncoprotein and hormone receptor negativity were significantly associated with poor response. Response rate in patients with c-erbB2-overexpressing tumours was 32% compared with 65% in patients with no c-erbB2 overexpression (P = 0.0058). Accordingly, the response rate for ER-positive patients was 67% compared with 26% in ER-negative patients (P = 0.0021). Although both negative ER status and c-erbB2 overexpression are associated with high Topo IIalpha expression in breast cancer, step-wise logistic regression analysis showed that ER and c-erbB2 were associated with therapy response independent of Topo IIalpha expression. Histological grade, p53, DNA-ploidy, tumour proliferation rate (S-phase fraction), stage of the disease at diagnosis, age of the patient, previous anti-oestrogen therapy or site of metastasis did not predict the response to epirubicin therapy. In conclusion, despite extensive in vitro evidence, expression of Topo IIalpha is unlikely to predict the response to Topo II inhibitor chemotherapy in advanced breast cancer. Among the prognostic biomarkers, overexpression of c-erbB2 oncogene and negative ER may have predictive value in epirubicin therapy in patients with advanced breast cancer.

Muscle strain injuries

Muscle injuries--lacerations, contusions or strains--are by far the most common injuries in sports. After first aid following the RICE principle (Rest, Ice, Compression and Elevation), therapy must be tailored according to the severity of the injury and based on the knowledge gained from experimental studies on regeneration of injured muscle. Most muscle injuries can be treated conservatively with excellent recovery, but complete ruptures with complete loss of function should be managed surgically. Immediately after the injury, a short period of immobilization is needed to accelerate formation of the scar between the stumps of the ruptured myofibers, to which the stumps adhere. The optimal length of immobilization depends on the grade of the injury, and should not be longer than needed for the scar to bear the pulling forces without rerupture. Early mobilization is required to invigorate adhesion, orientation of the regenerating muscle fibers, revascularization and resorption of the connective tissue scar. Another important aim of early mobilization, especially in clinical sports medicine, is to minimize inactivity-induced atrophy as well as loss of strength and extensibility, which are rapidly appearing adverse sequelae of prolonged immobilization.