Healthcare professionals' digital health competence and its core factors; development and psychometric testing of two instruments.

BACKGROUND: Healthcare professionals' digital health competence is an important phenomenon to study as healthcare practices are changing globally. Recent research aimed to define this complex phenomenon and identify the current state of healthcare professionals' competence in digitalisation but did not include an overarching outlook when measuring digital health competence of healthcare professionals. OBJECTIVES: The purpose of this study was to develop and psychometrically validate two self-assessed instruments measuring digital health competence and factors associating with it. METHODS: The study followed three phases of instrument development and validation: 1) conceptualisation and item pool generation; 2) content validity testing and pilot study; and 3) construct validity and reliability testing. The conceptual background of the instruments was based on individual interviews conducted with healthcare professionals (n = 20) and previous systematic reviews. A total of 17 experts assessed the instrument's content validity. Face validity was evaluated by a group of healthcare professionals (n = 20). Data collection from 817 professionals took place in spring-summer 2022 in nine organisations. Construct validity was confirmed with exploratory factor analysis. Cronbach's alpha was used to assess the internal consistency of the instruments. RESULTS: The instrument development and validation process resulted in two instruments: DigiHealthCom and DigiComInf. DigiHealthCom included 42 items in 5 factors related to digital health competence, and DigiComInf included 15 items in 3 factors related to educational and organisational factors associated with digital health competence. The DigiHealthCom instrument explained 68.9 % of the total variance and the factors' Cronbach alpha values varied between 0.91 and 0.97. The DigiComInf instrument explained 59.6 % of the total variance and the factors' Cronbach alpha values varied between 0.76 and 0.88. CONCLUSIONS: The two instruments gave valid and reliable results in psychometric testing. The instruments could be used to evaluate healthcare professionals' digital health competence and associated factors.

Collegiality among social- and health care educators in higher education or vocational institutions: A mixed-method systematic review.

BACKGROUND: Social- and health care educators collaborate on national and international levels; this collaboration is intrinsically related to collegiality, a concept which has only been scarcely studied among social- and health care educators. OBJECTIVES: To identify the best evidence on social- and health care educators' experiences of collegiality and factors influencing it in educational institutions. DESIGN: A mixed-methods systematic review. DATA SOURCES: Keywords were defined according to PICo and PEO inclusion and exclusion criteria. A search was performed across five databases (CINAHL, PubMed, Medic, Scopus, and ProQuest) for articles published in Finnish and/or English REVIEW METHODS: During the screening process, three researchers separately screened original studies by title and abstract (n = 806), and subsequently, based on the full-text (n = 40). The JBI Qualitative Assessment Research Instrument was used to evaluate qualitative studies, while the Critical Appraisal Checklist for Analytical Cross-sectional Studies was used to evaluate quantitative studies. RESULTS: The systematic review included a total of 15 articles. Collegiality among social- and health care educators was described through united and safe work culture, along with the dissemination of relevant expertise. The benefits of mentoring, communication on national and international levels, and collaboration are all issues that affect an educator's work. In the context of social- and health care educators, collegiality does not only include the interactions between the educators, but also involves their mentors and supervisors. Mentoring and collaboration between educational institutions were found to be associated with collegiality. CONCLUSIONS: Collegiality among educators can be maintained through networking, collaboration, mentoring, mutual communication and the consideration of professional ethical issues. It would be important for educational organisations to pay attention to collegiality and encourage educators to collaborate with their colleagues. It is important to emphasise the role of collegiality in the education of new social- and health care teacher candidates and the continuing education of current educators.

Autologous reconstructions are associated with greater overall medium-term care costs than implant-based reconstructions in the Finnish healthcare system: A retrospective interim case-control cohort study.

PURPOSE: Previous studies have mainly reported the short-term costs of different reconstruction techniques. Revision operations may increase costs in longer follow-up. Authors report medium-term data on different reconstruction methods. We hypothesised that the reconstruction method would affect not only the duration of reconstruction process but also total costs. METHODS: The reconstruction database was reviewed from 2008 to 2019. Women with autologous (deep inferior epigastric perforator, transverse musculocutaneous gracilis and latissimus dorsi [LD] without implant) and implant-based (implant and LD with implant) reconstructions were included. Variables evaluated included age, body mass index, smoking, comorbidities, radiotherapy, complications and readmissions. Risk factors for multiple revision surgeries were analysed. Time to definitive reconstruction and related costs were also calculated. RESULTS: In total, 591 patients with autologous reconstructions and 202 with implant-based reconstructions were included. The median follow-up time was 73 months. Definitive reconstruction was obtained in 443 days in implant-based reconstructions and in 403 days in autologous reconstructions (P = 0.050). Independent risk factors for multiple surgeries were younger age (P < 0.001) and comorbidity (P = 0.008). No statistically significant difference was observed in the rate of overall surgical procedures (P = 0.098), but implant-based reconstructions were more commonly associated with two or more planned operations (P = 0.008). Autologous reconstructions were associated with greater total cost ($22 052 vs. $18 329, P < 0.001). CONCLUSIONS: This review of reconstructions over a 12-year study period revealed that autologous reconstructions are associated with greater overall costs, but there is no statistically significant difference in reconstruction time or rate of surgical procedures. However, a full cost assessment between reconstructive techniques requires a much longer follow-up period.

Patient satisfaction with telephone care assessment among patients with non-urgent prehospital emergency care issues: A cross-sectional study.

BACKGROUND: Telephone care assessment (TCA) by a nurse have shown to reduce the number of emergency department (ED) visits and emergency medical services missions (EMS). The present study aimed to describe satisfaction among patients with non-urgent prehospital medical issues that were transferred to TCA instead of receiving EMS. These results could provide a basis for developing the telephone services and emergency care pathways. METHODS: This cross-sectional study included 765 patients with non-urgent issues that were transferred to a telephone care assessment, after a risk and urgency assessment by an emergency medical communications operator. One week later, patient satisfaction was evaluated in a structured telephone interview with randomized patients. RESULTS: 127 telephone interviews were completed.Most patients (70.9-85.0%) were highly satisfied with the telephone care assessment. In particular,patients who were unsure of the urgency of their own health condition and the need for EMS, were highly satisfied (95.3%). Patients that received EMS after the telephone care assessment were more satisfied than those that received telephone guidance or those directed to other health care services (91.4% vs. 65.5% vs. 67.9%, p = 0.002). CONCLUSION: Patients with non-urgent prehospital emergency issues were mainly satisfied with telephone care assessment. In considering ways to reduce the increasing load on emergency medical services, a telephone care assessment could be a good option, without reducing patient satisfaction.

Patients', radiographers' and radiography students' experiences of 360° virtual counselling environment for the coronary computed tomography angiography: A qualitative study.

INTRODUCTION: The aim of this study was to describe patients', radiographers' and radiography students' experiences of the developed 360° virtual counselling environment (360°VCE) for the coronary computed tomography angiography (cCTA). METHODS: A descriptive qualitative approach was used. The participants were cCTA patients (n = 10), radiographers (n = 10) and radiography students (n = 10) who used the 360°VCE and visited or worked at a university hospital in Finland. The 360°VCE, resembling the authentic environments of a CT imaging unit, included digital counselling materials in text, image, animation and video formats. Data were gathered through thematic interviews individually to obtain an understanding of participants' perspectives and analyzed by inductive content analysis. RESULTS: Five main categories and 15 categories were identified. Identified benefits of the 360°VCE for patients included improvements in knowledge, spatial and environmental orientation, and senses of security and self-efficacy, with reductions in fear and nervousness. Patients found the counselling materials engaging, and that the 360° technology conveniently provided reassuring familiarity with the environment before their visit. Identified benefits for radiographers and radiography students included improvements in patients' mental preparedness, knowledge, spatial and environmental orientation, and reductions in patients' fear, which eased procedures and enhanced diagnostic success. The 360°VCE also provided useful information and familiarization with the cCTA unit for students during clinical practice and staff of referring units.  CONCLUSION: It seems that patients', radiographers' and radiography students' experiences of 360°VCE respond to patients' needs by improved knowledge and reduced fears. Thus, current counselling practices can be usefully complemented with spherical panoramic imaging technology and online information delivery. IMPLICATIONS FOR PRACTICE: The results may be used to improve patient counselling and care, thereby optimizing the cCTA examination procedure and reducing fear. However, further research is needed to characterize experiences of the 360° VCE more comprehensively.

Predictive risk factors of complications in different breast reconstruction methods.

PURPOSE: Women with different BMI, age and comorbidities seek for breast reconstruction. It is critical to understand the risk associated with each technique to ensure the most appropriate method and timing is used. Outcome after reconstructions have been studied, but consensus is lacking regarding predictive risk factors of complications. The authors present their experience of different autologous and alloplastic reconstructions with an emphasis on predictors of complications. METHODS: Prospectively maintained reconstruction database from 2008 to 2019 was reviewed. Factors associated with complications were identified using logistic regression, multinomial logistic regression and risk factor score to determine predictors of complications. RESULTS: A total of 850 breast reconstructions were performed in 793 women, including 447 DIEP, 283 LD, 12 TMG and 51 implant reconstructions. Complications included minor (n = 231, 29%), re-surgery requiring (n = 142, 18%) and medical complications (n = 7, 1%). Multivariable analysis showed that complications were associated independently with BMI > 30 (OR 1.59; 95% CI 1.05-2.39, p = 0.027), LD technique (OR 4.05; 95% CI 2.10-7.81, p < 0.001), asthma or chronic obstructive pulmonary disease (OR 2.77; 95% CI 1.50-5.12, p = 0.001) and immediate operation (OR 0.69; 95% CI 0.44-1.07, p = 0.099). Each factor contributed 1 point in the creation of a risk-scoring system. The overall complication rate was increased as the risk score increased (35%, 61%, 76% and 100% for 1, 2, 3 and 4 risk scores, respectively, p < 0.001). CONCLUSIONS: The rate of complication can be predicted by a risk-scoring system. In increasing trend of patients with medical problems undergoing breast reconstruction, tailoring of preventive measures to patients' risk factors and careful consideration of the best timing of reconstruction is mandatory to prevent complications and costs.

Nurses' knowledge of radiation protection: A cross-sectional study.

INTRODUCTION: Nursing roles are changing, as several countries have amended legislation so that nurses can make referrals for medical imaging examination that utilize ionising radiation. Nevertheless, nurses' radiation knowledge remains a poorly studied concept. The aim of the study was to characterize Finnish nurses' knowledge of radiation use and radiation safety. In this study, nurses were working in operating theaters, first aid clinics and cardiology laboratories. METHODS: A cross-sectional design was applied in which data were simultaneously collected from nurses working in eight hospitals. All nurses working in operating theaters, first aid clinics and cardiology laboratories (N = 1500) at the hospitals in Finland were invited to participate in the study. The response rate was 17% (n = 252). The employed Healthcare Professional Knowledge of Radiation Protection (HPKRP) scale included three areas of knowledge: radiation physics, biology and principles of radiation use; radiation protection; and guidelines of safe ionizing radiation use. Descriptive statistics and logistic regression analyses were used to identify factors that influence these three areas. RESULTS: Nurses reported high knowledge levels in radiation protection but low knowledge levels in radiation physics, biology and principles of radiation use. Moreover, nurses who had not received radiation education reported lower knowledges across all three areas than the nurses who had completed education. CONCLUSION: This study identified one major factor that significantly affects nurses' radiation knowledge, namely, having completed medical radiation education, as this factor positively influenced all three of the included areas of radiation knowledge factors. Therefore, healthcare organizations should concentrate on providing education to all nurses working with, or exposed to, radiation.

Development and validation of a psychometric scale for assessing healthcare professionals' knowledge in radiation protection.

INTRODUCTION: Healthcare professionals must sufficiently understand ionising radiation and the associated protection measures to avoid unnecessarily exposing patients and staff to ionising radiation. Hence, a proper safety culture is important to lowering health risks. The development and establishment of an instrument that can indicate healthcare professionals' understanding/knowledge of radiation protection concepts can greatly contribute to a good safety culture. The purpose of the present study was to develop and psychometrically test the Healthcare Professional Knowledge of Radiation Protection (HPKRP) self-evaluation scale, which was designed to measure the knowledge level of radiation protection by healthcare professionals working with ionising radiation in a clinical environment. METHODS: The presented research employed a cross-sectional study design. Data were collected from eight Finnish hospitals in 2017. A total of 252 eligible nurses responded to the newly developed HPKRP scale. The face and content validity were tested with the Content Validity Index (CVI). Explorative factor analysis was used to test construct validity, whereas reliability was tested with Cronbach's alpha. RESULTS: Overall S-CVI for the HPKRP scale was 0.83. Exploratory factor analysis revealed a three-factor model for the HcPCRP scale containing 33 items. The first factor was defined by Radiation physics and principles of radiation usage, the second factor by Radiation protection, and the third factor by Guidelines of safe ionising radiation usage. These three factors explained 72% of the total variance. Cronbach's alpha coefficient for the scale ranged from 0.93 to 0.96. CONCLUSION: The results provide strong evidence for the validity and reliability of the HPKRP scale. Additionally, educators can use the scale to evaluate healthcare students' understanding in radiation safety before and after education.

Overweight is Associated With Increased Incidence of Minor Complications After Reduction Mammoplasty: A Retrospective Analysis of 453 Consecutive Cases.

BACKGROUND AND AIMS: Reduction mammoplasty alleviates macromastia symptoms and improves quality of life. We investigated a large series of consecutive reduction mammoplasties to assess various risk factors for both minor and major complications after the procedure. MATERIALS AND METHODS: A retrospective analysis of 453 consecutive reduction mammoplasties was performed between 2007 and 2010 at an academic tertiary referral center to evaluate risk factors and complications. RESULTS: The incidence of minor and major complications was 40.5% and 8.8%, respectively. Patients with minor complications had both a significantly higher mean body mass index (30.2 vs 28.0) and sternal notch to nipple distance (33.9 vs 32.4 cm) than patients who recovered without complications (p < 0.001 for both comparisons), as well as more visits to the outpatient clinic (p < 0.001). In the multivariate analysis, body mass index was found to be the only significant risk factor for minor complications (p < 0.001). Furthermore, patients with body mass index higher than 27 had a 2.6-fold greater risk of minor complications (p < 0.001). An increase of one unit in body mass index increased the probability of minor complications by 14.1% (p < 0.001). 22 (4.9%) patients developed a hematoma requiring evacuation in the operating room. The mean body mass index of patients who developed a hematoma was 26.4, a value lower than that of patients without this complication (mean 29.0; p = 0.003). This finding was significant also in the multivariate analysis (p = 0.002). CONCLUSION: A higher body mass index was strongly associated with an increased risk of minor complications after reduction mammoplasty. It is important to inform obese patients about the increased risk of complications and to encourage them to lose weight before surgery.

Chest-wall contouring surgery in female-to-male transgender patients: A one-center retrospective analysis of applied surgical techniques and results.

BACKGROUND AND AIMS: Chest-wall contouring surgery is an important part of the gender reassignment process that contributes to strengthening the self-image and facilitating living in the new gender role. Here, we analyze the surgical techniques used in our clinic and report the results. MATERIAL AND METHODS: Female-to-male transgender patients (n = 57) undergoing chest-wall contouring surgery at Tampere University Hospital between January 2003 and April 2015 were enrolled in the study. Breast appearance was evaluated and either a concentric circular approach or a transverse incision technique was used for mastectomy. Patient characteristics and data regarding the technique and postoperative results were collected and analyzed retrospectively. RESULTS: In addition to the transgender diagnosis, 40.4% of the patients had another psychiatric diagnosis. For mastectomy, a concentric circular approach was used in 50.9% and a transverse incision approach in 49.1% of the patients. In the transverse incision group, 21.4% of the patients underwent pedicled mammaplasty and 78.6% mastectomy with a free nipple-areola complex graft. Compared with the transverse incision group, breasts were smaller (p < 0.001) and body mass index value was lower in the concentric circular group (p = 0.001). One-third of the patients had complications (hematoma, infection, seroma, fistula, or partial necrosis of nipple-areola complex) and the reoperation rate was 8.8%. Hematoma was the most frequent reason for reoperation. Corrections were required for the scar in 14.0% of the patients, the contour in 28.0%, the areola in 15.8%, and the nipple in 5.3%. Secondary corrections were needed more often in the concentric circular (55.2%) than in the transverse incision group (25.0%; p = 0.031). CONCLUSIONS: The larger the breast, poorer the skin quality, and greater the amount of excess skin, the longer the required incision and resulting scar is for mastectomy of female-to-male patients. Hematoma is the most common reason for acute reoperation and secondary corrections are often needed.

Greater Success of Primary Fascial Closure of the Open Abdomen: A Retrospective Study Analyzing Applied Surgical Techniques, Success of Fascial Closure, and Variables Affecting the Results.

BACKGROUND AND AIMS: The open abdomen technique is a standard procedure in the treatment of intra-abdominal catastrophe. Achieving primary abdominal closure within the initial hospitalization is a main objective. This study aimed to analyze the success of closure rate and the effect of negative pressure wound therapy, mesh-mediated medial traction, and component separation on the results. We present the treatment algorithm used in our institution in open abdomen situations based on these findings. MATERIAL AND METHODS: Open abdomen patients (n = 61) treated in Tampere University Hospital from May 2005 until October 2013 were included in the study. Patient characteristics, treatment prior to closure, closure technique, and results were retrospectively collected and analyzed. The first group included patients in whom direct or bridged fascial closure was achieved, and the second group included those in whom only the skin was closed or a free skin graft was used. Background variables and variables related to surgery were compared between groups. RESULTS AND CONCLUSION: Most of the open abdomen patients (72.1%) underwent fascial defect repair during the primary hospitalization, and 70.5% of them underwent direct fascial closure. Negative pressure wound therapy was used as a temporary closure method for 86.9% of the patients. Negative pressure wound therapy combined with mesh-mediated medial traction resulted in the shortest open abdomen time (p = 0.039) and the highest fascial repair rate (p = 0.000) compared to negative pressure wound therapy only or no negative pressure wound therapy. The component separation technique was used for 11 patients; direct fascial closure was achieved in 5 and fascial repair by bridging the defect with mesh was achieved in 6. A total of 8 of 37 (21.6%) patients with mesh repair had a mesh infection. The negative pressure wound therapy combined with mesh-mediated medial traction promotes definitive fascial closure with a high closure rate and a shortened open abdomen time. The component separation technique can be used to facilitate fascial repair but it does not guarantee direct fascial closure in open abdomen patients.

Chitosan membranes in a rat model of full-thickness cutaneous wounds: healing and IL-4 levels.

OBJECTIVE: The aim of this study was to examine the effect of chitosan membrane on wound healing. METHOD: The effect of chitosan membranes was evaluated in an experimental rat model. On day 0, circular full-thickness skin sections were excised from the scalps of rats. The wounds were then measured and the surrounding area tattooed. Rats were sacrificed either immediately after excision, or randomised into control and chitosan groups and followed up on day 3, 7, 14 or 21. Control group wounds were covered with Aquacel (wound dressing). Chitosan group wounds were covered with chitosan membranes and the wound dressing. Wounds and the distances between the tattooed marks were measured on follow-up, the wound sites were harvested and histologically examined, and serum interleukin (IL-4) levels were analysed. RESULTS: A total of 54 rats were examined and all time points included 6 control and 6 chitosan treated animals, except for day 0 which consisted of control animals only. On day 3, wounds in the chitosan group were significantly (p<0.05) smaller (60±6% versus 78±19% of the original wound area) than in the control group. Chitosan membranes were found to degrade at the wound sites between days 7 and 14. Leukocyte counts were lower in the chitosan group than in the control group on day seven (p<0.05). IL-4 levels were significantly higher on day 7 (p<0.001) and 14 (p<0.001) in the chitosan group. CONCLUSION: According to our results chitosan membrane may promote early wound healing, reduce inflammation and affect the IL-4 pathway, however, the membrane degrades at the wound site after day 7.

Successful foot salvage with microvascular flaps in diabetic patients.

BACKGROUND AND AIMS: Complex nontraumatic foot lesions often lead to major lower-limb amputation in diabetic patients. We aimed to evaluate outcome of free flap transfer in such cases. MATERIALS AND METHODS: A total of 11 consecutive diabetic patients, hospitalized between 2007 and 2012 at a university central hospital for a free flap transfer, were followed until September 2013. Amputation-free survival, patient survival, and complete wound healing were defined as primary endpoints. Healing time of tissue lesions was analyzed. All pre- and postoperative data were retrospectively collected from hospital charts. RESULTS: Complete tissue healing at 6 and 12 months after free flap transfer were 55% (6/11) and 82% (9/11), respectively. The median time to complete tissue healing was 123 days (range, 45-207 days). Overall limb salvage, survival, and amputation-free survival rates at 12 months were 90%, 91%, and 82%, respectively. The clinically important endpoint, namely, amputation-free survival with completely healed wounds, was attained in 9 of 11 patients at 1 year. CONCLUSION: Free tissue transfer enables successful wound healing and limb salvage rather than amputation in selected diabetic patients with difficult-to-heal wounds. Complete healing of tissue lesions is slow even after successful surgery. Preoperative assessment of the condition of patients is the key to success.

Effectiveness of educational programmes in preventing ventilator-associated pneumonia: a systematic review.

BACKGROUND: Ventilator-associated pneumonia (VAP) is the most frequent device-associated, nosocomial infection encountered in critical-care settings, associated with substantial morbidity, a two-fold increase in mortality rates and excess costs. According to previous studies, critical-care nurses' knowledge of and adherence to guidelines for preventing VAP is low in the absence of educational interventions. AIM: The aim of this study was to assess the current body of literature regarding the effectiveness of educational programmes, with a focus on learning and clinical outcomes, in order to identify ways to intensify current research. METHODS: Studies published between 2003 and 2012 contained in seven multi-disciplinary databases (Medline Ovid(®), the Cumulative Index to Nursing and Allied Health Literature, Cochrane Library, Scopus, Web of Science, Medic, and Academic Search Premier) were reviewed. A comprehensive literature search strategy was conducted in association with an information specialist. The study selection process was carried out by two researchers independently and objectively. FINDINGS: Eight original studies were included in the final review. Increasing the education of intensive care unit (ICU) personnel was linked to a significant improvement in the level of knowledge and adherence to guidelines and significant improvement in clinical outcomes, i.e. decreased incidence of VAP, length of ICU and hospital stays, mortality and costs. CONCLUSIONS: Education has significant benefits for improving patient safety, and thus the quality of care. Active implementation strategies involving repeated lectures and regular surveys of VAP occurrence would be beneficial. Further research is needed to design multi-centre, randomized, controlled, follow-up studies. Development of a universal method of outcome measurement is required to facilitate further evaluation of the relationship between educational programmes and clinical outcomes.

Primary closure of the abdominal wall after "open abdomen" situation.

"Open abdomen" is a strategy used to avoid or treat abdominal compartment syndrome. It has reduced mortality both in trauma and non-trauma abdominal catastrophes but also has created a challenging clinical problem. Traditionally, open abdomen is closed in two phases; primarily with a free skin graft and later with a flap reconstruction. A modern trend is to close the abdomen within the initial hospitalization. This requires multi-professional co-operation. Temporary abdominal closure methods, e.g. negative pressure wound therapy alone or combined with mesh-mediated traction, have been developed to facilitate direct fascial closure. Components separation technique, mesh reinforcement or bridging of the fascial defect with mesh and perforator saving skin undermining can be utilized in the final closure if needed. These techniques can be combined. Choice of the treatment depends on the condition of the patient and size of the fascia and skin defect, and the state of the abdominal contents. In this paper we review the literature on the closure of an open abdomen and present the policy used in our institution in the open abdomen situations.

Amniotic membrane reduces wound size in early stages of the healing process.

OBJECTIVE: To investigate the effects of dispase de-epithelialised, glycerol cryopreserved amniotic membrane (AM) on full-thickness skin defects, using a rat model. METHOD: Skin defects of 15 mm diameter were surgically created and measured on the scalps of 53 male rats. Animals were divided into two groups and followed for 0, 3, 7, 14 or 21 days. AM group wounds were covered with de-epithelialised AM and sodium chloride-moistened Aquacel (ConvaTec Inc.); control group wounds were covered with sodium chloride-moistened Aquacel alone. After the follow-up, wounds were measured again, serum samples were taken and wound sites were harvested for histological analysis. Systemic interleukin-4 (IL-4) levels were analysed from serum. RESULTS: On day 3, a statistically significant difference (p < 0.01) was observed in mean wound size, with wound size in the AM group smaller than in the control group (60 ± 12% vs 81 ± 13% of the original size); other time points showed no significance difference in wound size between the two groups. We could not detect differences between the groups in histological parameters or serum IL -4 levels. CONCLUSION: According to this study, AM enhances early stage wound healing in terms of wound size but its effect decreases in later phases. The IL-4 results provide no clear evidence that IL-4 contributes to the effect of AM on wound healing. DECLARATION OF INTEREST: This study was financially supported by the Competitive Research Funding of the Tampere University Hospital (Grant 9H041, 9J047). The authors have no additional conflicts of interest to declare.

Regulation of alpha7 integrin by mechanical stress during skeletal muscle regeneration.

The continuity of the tendon-myofibre-tendon units disrupted by shearing injury must be re-established during regeneration. We have previously demonstrated in freely moving rats that transected myofibres reinforce their lateral integrin-mediated adhesion, with the maximum around days 5-7. After day 14, most integrin molecules are redistributed to the newly formed myotendinous junctions, by which the ends of regenerating myofibres attach to the scar between the stumps. Here, we analyzed the effects of mechanical stress (free and forced mobilization vs. immobilization and denervation separately and in combination) on the expression of alpha7 integrin and merosin in regenerating myofibres using quantitative in situ hybridization and immunohistochemistry. In all groups, alpha7 integrin expression was upregulated at mRNA level, whereas increased protein accumulation in lateral sarcolemma occurred only in the mobilized groups. The accumulation of merosin was not affected by the stress level. The results demonstrate that active mechanical stress reinforces early lateral integrin-mediated adhesion; molecules may at the same time mediate signals from matrix to cells for adaptation to the altered biomechanical status.

Relation between myofibers and connective tissue during muscle injury repair.

The connective tissue framework in skeletal muscle combines the contractile myofibers into a functional unit, in which the contraction of myofibers is transformed into movement via myotendinous junctions (MTJs) at their ends, where myofibers attach to tendons/fascia. The cytoskeletal contractile myofilament apparatus adheres through subsarcolemmal and transmembrane molecules to the surrounding extracellular matrix, with integrin and dystrophin associated chains of molecules being the two main adhesion complexes. In shearing type of muscle injury both myofibers and the connective tissue framework are ruptured and thereby the functional tendon-muscle-tendon units are disrupted. The stumps of the ruptured myofibers are separated and at the same time joined by a connective tissue scar, through which the ends of regenerating myofibers try to pierce, but as the scar becomes more compact the ends attach to the scar by new mini-MTJs. During the early phase ruptured myofibers try to compensate for the lost MTJ attachment by reinforcing their integrin mediated lateral adhesion, which returns to normal low level after formation of the mini-MTJs and at which time complementary increase of dystrophin and associated molecules on lateral sarcolemma takes place. The stumps appear to remain separated by and attached to the interposed scar for many months, possibly for ever, i.e. the original tendon-muscle-tendon units may have become permanently divided into two consecutive units. Remarkably, axon sprouts are able to penetrate through the interposed scar to form new neuromuscular junctions on those abjunctional stumps which were denervated by the rupture.

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.

Integrin and dystrophin associated adhesion protein complexes during regeneration of shearing-type muscle injury.

In shearing injury both the myofibres and connective tissue framework are breached and the muscle tendon continuity is disrupted. During regeneration the firm myofibre to extracellular matrix (ECM) adhesion must be re-established. We have analysed the expression of selected molecules implementing this adhesion in regenerating myofibres 2-56 days after transection of rat soleus muscle using quantitative immunohistochemistry and Northern blotting. Beta1 integrin mRNA level and alpha7 integrin and vinculin immunoreactivities were transiently increased in both the intact and regenerating parts of the transected myofibres by day 5-7 with normalization by day 10-14. After day 14, alpha7 integrin and vinculin accumulated at the tips of the regenerating myofibres, indicating formation of new mini-myotendinous junctions (mMTJ). Immunoreactivities for dystrophin and associated proteins as well as merosin appeared in regenerating myotubes by day 3-4 reaching control levels by day 56. Our results suggest that integrin and dystrophin associated molecules are complementary in myofibre-ECM adhesion. During regeneration, ruptured myofibres temporarily reinforce their integrin mediated lateral adhesion until mMTJs are formed. Thereby the load on the newly formed scar and the risk of rerupture are reduced. Dystrophin associated molecules appear later and replace integrin on the lateral aspects, while both complexes are abundant at the mMTJs. These molecular events correspond to our previous results on tensile strength.