Effect of muscular fatigue on the cumulative lumbar damage during repetitive lifting task: a comparative study of damage calculation methods.

Several methods have been put forward to quantify cumulative loads; however, limited evidence exists as to the subsequent damages and the role of muscular fatigue. The present study assessed whether muscular fatigue could affect cumulative damage imposed on the L5-S1 joint. Trunk muscle electromyographic (EMG) activities and kinematics/kinetics of 18 healthy male individuals were evaluated during a simulated repetitive lifting task. A traditional EMG-assisted model of the lumbar spine was modified to account for the effect of erector spinae fatigue. L5-S1 compressive loads for each lifting cycle were estimated based on varying (i.e. actual), fatigue-modified, and constant Gain factors. The corresponding damages were integrated to calculate the cumulative damage. Moreover, the damage calculated for one lifting cycle was multiplied by the lifting frequency, as the traditional approach. Compressive loads and the damages obtained through the fatigue-modified model were predicted in close agreement with the actual values. Similarly, the difference between actual damages and those driven by the traditional approach was not statistically significant (p = 0.219). However, damages based on a constant Gain factor were significantly greater than those based on the actual (p = 0.012), fatigue-modified (p = 0.017), and traditional (p = 0.007) approaches.Practitioner summary: In this study, we managed to include the effect of muscular fatigue on cumulative lumbar damage calculations. Including the effect of muscular fatigue leads to an accurate estimation of cumulative damages while eliminating computational complexity. However, using the traditional approach also appears to provide acceptable estimates for ergonomic assessments.

Radioproteomics modeling of metformin-enhanced radiosensitivity: an animal study.

PURPOSE: Metformin is considered as radiation modulator in both tumors and healthy tissues. Radiomics has the potential to decode biological mechanisms of radiotherapy response. The aim of this study was to apply radiomics analysis in metformin-induced radiosensitivity and finding radioproteomics associations of computed tomography (CT) imaging features and proteins involved in metformin radiosensitivity signaling pathways. MATERIALS AND METHODS: A total of 32 female BALB/c mice were used in this study and were subjected to injection of breast cancer cells. When tumors reached a mean volume of 150 mm3, mice were randomly divided into the four groups including Control, Metformin, Radiation, and Radiation + Metformin. Western blot analysis was performed after treatment to measure expression of proteins including AMPK-alpha, phospho-AMPK-alpha (Thr172), mTOR, phospho-mTOR (Ser2448), phospho-4EBP1 (Thr37/46), phospho-ACC (Ser79), and ß-actin. CT imaging was performed before treatment and at the end of treatment in all groups. Radiomics features extracted from segmented tumors were selected using Elastic-net regression and were assessed in terms of correlation with expression of the proteins. RESULTS: It was observed that proteins including phospho-mTOR, phospho-4EBP1, and mTOR had positive correlations with changes in tumor volumes in days 28, 24, 20, 16, and 12, while tumor volume changes at these days had negative correlations with AMPK-alpha, phospho-AMPK-alpha, and phospho-ACC proteins. Furthermore, median feature had a positive correlation with AMPK-alpha, phospho-ACC, and phospho-AMPK-alpha proteins. Also, Cluster shade feature had positive correlations with mTOR and p-mTOR. On the other hand, LGLZE feature had negative correlations with AMPK-alpha and phospho-AMPK-alpha. CONCLUSION: Radiomics features can decode proteins that involved in response to metformin and radiation, although further studies are warranted to investigate the optimal way to integrate radiomics into biological experiments.

Metformin attenuates cisplatin-induced genotoxicity and apoptosis in rat bone marrow cells.

Metformin is widely used as an oral hypoglycemic drug in the management of type 2 diabetes mellitus. This study evaluated the possible protective effects of metformin against cisplatin-induced genotoxicity and apoptosis in rat bone marrow cells. Two different doses of metformin (50 and 100 mg/kg b.w.) were administered orally to experimental animals for seven consecutive days. On the seventh day, the rats were exposed to cisplatin (5 mg/kg, i.p.) 1 h after the last oral metformin administration. Rats in the control group were treated orally with 10 ml/kg PBS for 7 consecutive days and a single intraperitoneal injection of saline (0.9%) on the 7th day. The antagonistic effects of metformin against cisplatin were evaluated using micronucleus assay, reactive oxygen species (ROS) level analysis, hematological analysis, and flow cytometry. Treatment with 50 and 100 mg/kg metformin before cisplatin injection produced a significant reduction in the frequencies of micronucleated polychromatic erythrocytes (MnPCEs) and micronucleated normochromatic erythrocytes (MnNCEs) 24 h after cisplatin treatment with a corresponding increase in the PCE/(PCE + NCE) ratio. Moreover, metformin markedly elevated the levels of both red and white blood cells in peripheral blood and decreased the percentage of apoptotic cells and the ROS level in bone marrow cells of rats treated with cisplatin. The data suggest that metformin has potential chemoprotective properties in rat bone marrow after cisplatin treatment, which support its candidature as a potential chemoprotective agent for cancer patients undergoing chemotherapy.

Saddle seat reduces musculoskeletal discomfort in microsurgery surgeons.

Background. Microsurgery is a surgical procedure requiring a high degree of precision and is commonly facilitated through the use of an intraoperative microscope. When operating the microscope system, the long-term posture leads to musculoskeletal disorders in surgeons, and seats are commonly employed to diminish these problems. The present study was conducted to evaluate musculoskeletal discomfort during work with a saddle seat in comparison with conventional seats for microscopic work. Methods. Two types of seats, a saddle and a conventional one, were evaluated for 73 microsurgical surgeons in terms of musculoskeletal discomfort. Corlett and Bishop's body part discomfort scale was used to assess musculoskeletal discomfort before and after working with the seats. Results. The highest amount of discomfort that microsurgical surgeons acquire in the workplace was focused on their neck, shoulders, arms and back. During work with a saddle seat, a significant reduction was found for discomfort values in the neck, shoulder, arm, back, elbow and forearm, as well as the whole body (p < 0.05). Conclusion. This study showed that the use of saddle seats provides a more appropriate physical posture at work, and can decrease musculoskeletal discomfort in different parts of the body of microsurgical surgeons.

Efficacy of topical chamomile oil for mild and moderate carpal tunnel syndrome: A randomized double-blind placebo-controlled clinical trial.

OBJECTIVE: To evaluate the efficacy of topical chamomile oil in patients with mild and moderate carpal tunnel syndrome (CTS). METHOD: Eighty six patients with electrodiagnostic criteria of mild and moderate CTS were enrolled in this randomized double-blind placebo-controlled clinical trial and received wrist splint plus topical chamomile oil or placebo for 4 weeks. They were evaluated at the baseline and end of the study regarding functional and symptomatic scores, dynamometry, and electrodiagnostic indexes. RESULTS: Dynamometry, functionality, and symptom severity scores of the patients were significantly improved in the chamomile oil group compared with the placebo group (P = 0.040, P = 0.0001, P = 0.017, respectively). Additionally, compound latency of the median nerve in the chamomile oil group significantly decreased (P = 0.035) compared to the placebo group. Other electerodiagnostic measurements did not change significantly. CONCLUSION: Complementary treatment with topical chamomile oil may have some benefits for patients with mild and moderate CTS, both subjectively and objectively.

An ergonomic intervention to reduce musculoskeletal discomfort among semiconductor assembly workers.

BACKGROUND: Work-related musculoskeletal disorders (MSDs) and ergonomics-related injuries are the single largest category of workplace injuries and are responsible for almost 30% of all worker's compensation costs. Awkward working posture refers to positions of the body that deviate significantly from the neutral position while job tasks are being performed and it is the primary ergonomic risk factor for developing musculoskeletal discomfort. OBJECTIVE: This study was conducted among assembly workers of a semiconductor in Tehran province with the objective of implementing an interventional ergonomic program to minimize musculoskeletal discomfort. METHODS: This study that was conducted on 105 male assembly workers of a semiconductor industry based on a census method. The standardized Nordic Musculoskeletal Questionnaire (NMQ) was used to determine the prevalence of MSDs. Corlett and Bishop's body part discomfort scale (BPD) was applied to evaluate body discomfort before and after the intervention (using a magnifying loupes to improve visibility of the parts). RESULTS: The results of NMQ showed the highest rate of MSDs were in neck, shoulder, upper arm and lower back regions (more than 75%). After ergonomic intervention, significant decrements of discomfort was observed in neck, shoulder, upper arm, elbows, lower arm, lower back and whole body discomfort (p < 0.05). CONCLUSIONS: It can be concluded that using magnifying loupes reduced discomfort in different body regions and the whole body. A conclusion of this research is that ergonomic interventions can decrease MSDs of at risk body regions in the long term.

The effect of foot hyperpronation on spine alignment in standing position.

Background: According to clinical observations, foot hyperpronation is very prevalent and may cause malalignment of the lower extremity, leading to structural and functional deficits in standing and walking. This study aimed at investigating the effect of foot hyperpronation on spine alignment in the standing position. Methods: Thirty-five healthy males with an age range of 18-30 years participated in this cross-sectional study. Evaluation was performed with two examiners in four standing positions (on the floor, and on the wedges angled at 10, 15, and 20 degrees) using a motion analysis system (Zebris). Moreover, each of the measurement methods was repeated for three short times. Paired t- test and repeated measures ANOVA test were used for statistical analysis. Results: Significant differences were observed between all modes in the sacral angle, pelvic inclination, lumbar lordosis, and thoracic kyphosis variables (except between the first and second mode). Finally, a positive correlation was obtained for the examiners and all the variables with an increasing slope of the angle of wedge. Conclusion: The results of the present study revealed sacral angle, pelvic inclination, lumbar lordosis, and thoracic kyphosis were increased with an increase in bilateral foot pronation. In fact, each one of them is a compensatory phenomenon.

Influence of heel design in an orthopedic shoe on ground reaction forces during walking.

BACKGROUND: One of the treatments prescribed for musculoskeletal patients is orthopedic shoe. The use of an orthopedic shoe is thought to produce a more typical ground reactive force pattern. OBJECTIVES: This study was designed to determine the influence of three heel designs of an orthopedic shoe on the ground reaction forces during walking in healthy subjects. STUDY DESIGN: Quasi-experimental. METHOD: In total, 30 healthy adults (12 males, 18 females) walked at a self-selected pace for six trials in each of the three shoe conditions having three different heels which included the following: standard heel, beveled heel, and positive posterior heel flare. For each trial, ground reaction force parameters were recorded using a force plate. RESULTS: Repeated measures analysis of variance indicated that the impact force was significantly reduced for the positive posterior heel flare condition by 8% and 13% compared with standard and beveled heels, respectively (p < 0.001). The first peak of vertical force showed a significant reduction in the beveled heel by 5% and 4% compared with the standard heel and the positive posterior heel flare, respectively (p < 0.001). Loading rate was significantly reduced in the beveled heel and the positive posterior heel flare conditions (p < 0.05). CONCLUSION: Positive posterior heel flare reduced impact force due to its geometry flexibility, while a beveled heel reduced first peak of vertical force. The findings of this study show that the shape of the heel therefore has the potential to modify impact loads during walking. CLINICAL RELEVANCE: This study provides new evidence that by changing shape in the heel of orthopedic shoe impact loads are reduced during walking. Thus, these findings indicate that use of heel design may be beneficial for various musculoskeletal disorders, including key public health problems.

A pilot randomized double-blind placebo-controlled trial on topical chamomile (Matricaria chamomilla L.) oil for severe carpal tunnel syndrome.

OBJECTIVE: To assess the effectiveness of standardized topical Chamomile (Matricaria chamomilla L.) oil in patients with severe carpal tunnel syndrome, as a complementary treatment. METHOD: A pilot randomized double-blind placebo-controlled trial was conducted. Twenty six patients with documented severe carpal tunnel syndrome were treated in two parallel groups with a night splint plus topical chamomile oil or placebo. They were instructed to use their prescribed oil for 4 weeks, twice daily. Symptomatic and functional status of the patients and their electrodiagnostic parameters were evaluated when enrolled and after the trial period, as our outcome measures. RESULTS: A significant improvement of symptomatic and functional status of patients in the chamomile oil group was observed (p = 0.019 and 0.016, respectively) compared with those in the placebo group. However, electrodiagnostic parameters showed no significant changes between the two groups. CONCLUSION: Chamomile oil improved symptomatic and functional status of patients with severe carpal tunnel syndrome.

The comparison of Neoprene palumbo and Genu direxa stable orthosis effects on pain and activity of daily living in patients with patellofemoral syndrome: a randomized blinded clinical trial.

BACKGROUND: Patellofemoral pain syndrome (PFPS) is one of the most common disorders of the knee. Conservative approaches, as well as surgery, can decrease pain and the syndrome's progress effectively. OBJECTIVE: The aim of this study was to determine the effectiveness of neoprene palumbo orthosis (NPO) and Genu direxa stable orthosis (GDSO) on pain and the activities of daily living (ADL). METHODS: Thirty patients (males, ages 18 to 40) participated in this randomized blinded clinical trial. All of them were diagnosed with patella femoral pain syndrome. The participants were divided randomly into two groups of 15, with one group using neoprene palumbo (intervention group) and the other group using Genu direxa stable orthoses (control group). Using the Visual Analogue Scale (VAS) and the Knee injury and Osteoarthritis Outcome Score (KOOS), pain intensity and activities of daily living (ADL) and joint stiffness were analyzed before treatment and after three weeks of treatment. Data were analyzed using paired samples t-test and independent samples t-test. RESULTS: Both orthoses reduced the patients' pain. Both group showed meaningful improvement in pain reduction and ADL increase after using orthosis in each group. In comparing the variables, no significant differences were found between pain severity and ADL (p = 0.592, p = 0.887). In both groups, the mean of pain severity was different before, during, and after using orthosis (p < 0.05). CONCLUSION: The results of this study indicated that Neoprene palumbo and genudirexa stable orthoses improved the signs of patello femoral pain syndrome, including pain intensity and ADL.

Effect of rocker shoes on pain, disability and activity limitation in patients with rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis is a chronic inflammatory joint disease which affects the joints and soft tissues of the foot and ankle. Rocker shoes may be prescribed for the symptomatic foot in rheumatoid arthritis; however, there is a limited evidence base to support the use of rocker shoes in these patients. OBJECTIVES: The aim of this study was to evaluate the effectiveness of heel-to-toe rocker shoes on pain, disability, and activity limitation in patients with rheumatoid arthritis. STUDY DESIGN: Clinical trial. METHODS: Seventeen female patients with rheumatoid arthritis of 1 year or more duration, disease activity score of less than 2.6, and foot and ankle pain were recruited. Heel-to-toe rocker shoe was made according to each patient's foot size. All the patients were evaluated immediately, 7 and 30 days after their first visit. Foot Function Index values were recorded at each appointment. RESULTS: With the use of rocker shoes, Foot Function Index values decreased in all subscales. This reduction was noted in the first visit and was maintained throughout the trials. CONCLUSION: Rocker shoe can improve pain, disability, and activity limitation in patients with rheumatoid foot pain. All the subjects reported improved comfort levels. CLINICAL RELEVANCE: The results of this study showed that high-top, heel-to-toe rocker shoe with wide toe box was effective at reducing foot and ankle pain. It was also regarded as comfortable and acceptable footwear by the patients with rheumatoid foot problems.