The roles of lumbar load thresholds in cumulative lifting exposure to predict disk protrusion in an Asian population.

BACKGROUND: The purpose of this study was to determine whether a specific threshold per lifting movement, the accumulation above which best predicts lumbar disk protrusion, exists or the total lifting load should be considered. METHODS: This was a retrospective study. Subjects with various lifting exposures were recruited. Disk protrusion was assessed by magnetic resonance imaging. The cumulative lifting load was defined as the sum of the time-weighed lumbar load for each job and was calculated using a biomechanical software system. The effectiveness of accumulation above different thresholds in predicting disk protrusion were compared using four statistical methods. RESULTS: A total of 252 men and 301 women were included in the final analysis. For the men, 3000 Newtons for each lifting task was the optimal threshold for predicting L4-S1 disk protrusion, whereas for the women, 2800 Newtons was optimal. CONCLUSIONS: Our findings suggested that for cumulative lifting exposure, including the total lifting load without defining a minimal exposure limit might not be the optimal method for predicting disk protrusion. The NIOSH 3400 Newton recommended limits do not appear to be the optimal thresholds for preventing disk protrusion. Different lifting thresholds might be needed for men and women in the workplace for their safety.

Neuromechanical characteristics in the knees of patients who had primary conservative treatment for a torn cruciate ligament and reconstruction afterward.

BACKGROUND/PURPOSE: To compare the neuromechanical characteristics and subjective outcomes for knees of patients with a cruciate ligament tear and reconstruction with those for knees of controls at three time intervals, and to determine correlations between the characteristics and subjective outcomes. METHODS: Ten participants with a cruciate ligament tear and at least a 12-week conservative treatment prior to ligament reconstruction were prospectively measured prior to and 3 months and 6 months after surgery. Ten healthy individuals were recruited as controls. Questionnaire surveys regarding the injured knee were conducted, as were bilateral measurements of root mean square electromyography (EMG), the rate of EMG rise, the median frequency in the vastus medialis of the quadriceps muscles and antagonist coactivation from the semitendinosus muscle, and force capacities, including peak torque, rate of force development, and total works of the knee extension. Correlations between the EMG variables (of the vastus medialis and semitendinosus) and the force capacities, and between the EMG variables and the knee injury and osteoarthritis outcome scores (KOOS), and between force capacities and the KOOS were assessed in the participants with a ligament reconstruction. RESULTS: Pre- and postoperative results of EMG variable and force capacities were lower in both knees of the experimental group participants than in the control group participants (all p < 0.05). Correlations between EMG and force capacities, and between these parameters and the KOOS were found. CONCLUSION: There were bilateral neuromechanical defects in the knees of the participants who had undergone conservative treatment as well as reconstruction after a cruciate ligament tear.

Microcirculatory Responses to Muscle and Tendon Exercises in Individuals With and Without Type 2 Diabetes Mellitus and the Association Between Microcirculatory and Exercise Performance.

Background: This study aimed to measure and compare (1) the microcirculation and microcirculatory responses of the muscles and tendons at rest and during isometric muscle contractions in participants with and without diabetes mellitus (DM) and (2) to determine correlations between microcirculation and muscle strength. Methods: Sixty-three participants with type 2 DM and 42 physically matched controls were recruited. Baseline measurements of the microcirculation of the rectus femoris (RF) and medial gastrocnemius (MG) muscles and patellar (PT) and Achilles tendons (AT), as well as their microcirculatory changes during maximal isometric exercises, were performed and recorded by using near-infrared spectroscopy and a red laser. Data on various laboratory tests (including glycated hemoglobin, triglyceride, high-density cholesterol), the monofilament test, and the ankle-brachial index were also obtained. Results: The baseline measurements indicated that, compared with the controls, the diabetic participants had lower oxygen saturation (SpO2) in their RF and MG muscles (both P < 0.001), and the total hemoglobin in the diabetic PT and AT was higher (P = 0.001 and P = 0.01). The minimal SpO2 levels in the aforementioned muscles during isometric contractions were lower in the diabetes group than in the control group (P ≤ 0.001). Furthermore, there were correlations between the microcirculatory change of the RF muscle and the knee extension force. Conclusions: This study demonstrated the effects of diabetes on the microcirculation of skeletal muscles and tendons during baseline measurements and responses to maximal isometric exercises. The results support the need for preventive strategies for diabetic muscles to prevent adverse complications when performing resistance training.

Osteonecrosis in patients with human immunodeficiency virus type 1 infection in Taiwan.

Osteonecrosis, a disabling complication associated with antiretroviral therapy (ART) and human immunodeficiency virus (HIV) infection, has rarely been reported in an Asian population. After an observation of 3,250 person-years (PY), 11 of 967 (1.1%) HIV-infected patients at a median age of 34 years developed osteonecrosis involving the hip joints (incidence, 3.4 per 1,000 PY). Their median CD4+ lymphocyte count had increased from 35 cells/microL at the diagnosis of HIV infection to 297 cells/microL at the diagnosis of osteonecrosis. The crude rate of osteonecrosis increased from 0% in patients without exposure to ART to 2.6 and 1.7% in patients with exposure to nucleoside reverse transcriptase inhibitors (NRTIs) and who had undergone highly active antiretroviral therapy (HAART) for 5 years or longer, respectively (P=0.18 and 0.09, respectively). Among the patients receiving HAART, the estimated incidence of osteonecrosis was 4.2 per 1,000 PY. Patients with osteonecrosis had a longer duration of exposure to NRTIs (1,641 versus 1,264 days, P=0.26) and to HAART (1,603 versus 1,251 days, P=0.42), a higher serum triglyceride (median, 1,130 versus 351 mg/dL; P=0.09), and a higher proportion of lipodystrophy (81.8 versus 15.0%, P<0.0001). Our report suggests that osteonecrosis is a rare complication in HIV-infected patients with prolonged exposure to ART with resultant metabolic complications.

Perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging predict outcomes of hepatocellular carcinoma receiving radiotherapy with or without thalidomide.

BACKGROUND: To correlate between signal parameters using dynamic contrast-enhanced magnetic resonance imaging (DCEMRI) and outcomes of hepatocellular carcinoma (HCC) receiving radiotherapy with or without concomitant thalidomide. METHODS: DCEMRI was performed in advanced HCC patients undergoing radiotherapy with or without concomitant thalidomide. Initial first-pass enhancement slopes (slope) and peak enhancement ratios (peak) were measured over an operator-defined region of interest over tumor and non-tumor liver parenchyma. The perfusion parameters were correlated with clinical outcomes. The study was registered with ClinicalTrials.gov. (identifier NCT00155272). RESULTS: Forty-three patients were evaluable. There were 18 partial responses (PRs), 5 minimal responses (MRs), 17 stable diseases (SDs), and 3 progressive diseases (PDs). Baseline perfusion parameters as well as slope at 14 days of radiotherapy were higher in patients with PR or MR compared to SD or PD (0.81 ± 0.29 vs. 0.49 ± 0.34, p < 0.01; 0.39 ± 0.15 vs. 0.28 ± 0.16, p = 0.02; 0.97 ± 0.38 vs. 0.46 ± 0.26, p < 0.01; respectively). Multivariate analysis revealed perfusion parameters over liver parenchyma, but not over tumor, and independently predicted progression-free and overall survival (182 ± 33 vs. 105 ± 26 days, p = 0.01; 397 ± 111 vs. 233 ± 19 days, p = 0.001 respectively). For 22 patients receiving concomitant thalidomide, the perfusion parameters were not significantly different from those receiving radiotherapy alone. CONCLUSIONS: Signal parameters of DCEMRI over tumor and liver parenchyma correlated with tumor response and survival, respectively, in HCC patients receiving radiotherapy.

Reduced bone mineral density among HIV-infected patients in Taiwan: prevalence and associated factors.

BACKGROUND: Reduced bone mineral density (BMD) is an emerging threat to the successful long-term management of human immunodeficiency virus (HIV) infection among patients with access to combination antiretroviral therapy (cART). Data on the prevalence and associated factors of reduced BMD in Asian populations remain scarce. METHODS: From March 2002 to April 2006, a cross-sectional survey was conducted among HIV-infected patients aged ≥ 20 years at the National Taiwan University Hospital. BMD of the lumbar spine was measured with the use of dual-energy X-ray absorptiometry. Osteopenia was defined as a BMD T-score between -1.0 and -2.5, and osteoporosis was defined as a BMD T-score ≤ -2.5. Linear and ordinal logistic regression analyses were performed. RESULTS: Among 320 patients with a median age of 37.3 years, body mass index (BMI) of 21.4kg/m(2) and 94.4% on cART, osteopenia and osteoporosis were diagnosed in 35.6% and 3.8%, respectively. On multivariate linear analysis, factors associated with reduced BMD were increasing age (p=0.006), longer duration on antiretroviral therapy (p=0.007), and a decreasing BMI (p=0.002). Using ordinal logistic regression, being underweight with a body mass index (BMI)<18.5kg/m(2) was independently associated with reduced BMD (proportional odds ratio, 4.12; 95% confidence interval, 1.93-8.82). CONCLUSION: Reduced BMD was prevalent among HIV-infected Taiwanese adults on cART. Increased age, lower BMI, and exposure to antiretroviral therapy were significantly associated with decrease of BMD.

The dose-response relationship between cumulative lifting load and lumbar disk degeneration based on magnetic resonance imaging findings.

BACKGROUND: Lumbar disk degeneration (LDD) has been related to heavy physical loading. However, the quantification of the exposure has been controversial, and the dose-response relationship with the LDD has not been established. OBJECTIVE: The purpose of this study was to investigate the dose-response relationship between lifetime cumulative lifting load and LDD. DESIGN: This was a cross-sectional study. METHODS: Every participant received assessments with a questionnaire, magnetic resonance imaging (MRI) of the lumbar spine, and estimation of lumbar disk compression load. The MRI assessments included assessment of disk dehydration, annulus tear, disk height narrowing, bulging, protrusion, extrusion, sequestration, degenerative and spondylolytic spondylolisthesis, foramina narrowing, and nerve root compression on each lumbar disk level. The compression load was predicted using a biomechanical software system. RESULTS: A total of 553 participants were recruited in this study and categorized into tertiles by cumulative lifting load (ie, <4.0 × 10(5), 4.0 × 10(5) to 8.9 × 10(6), and ≥8.9 × 10(6) Nh). The risk of LDD increased with cumulative lifting load. The best dose-response relationships were found at the L5-S1 disk level, in which high cumulative lifting load was associated with elevated odds ratios of 2.5 (95% confidence interval [95% CI]=1.5, 4.1) for dehydration and 4.1 (95% CI=1.9, 10.1) for disk height narrowing compared with low lifting load. Participants exposed to intermediate lifting load had an increased odds ratio of 2.1 (95% CI=1.3, 3.3) for bulging compared with low lifting load. The tests for trend were significant. LIMITATIONS: There is no "gold standard" assessment tool for measuring the lumbar compression load. CONCLUSIONS: The results suggest a dose-response relationship between cumulative lifting load and LDD.

Dynamic MRI signals in the second week of radiotherapy relate to treatment outcomes of hepatocellular carcinoma: a preliminary result.

AIM: Radiotherapy (RT) has been used to treat hepatocellular carcinoma (HCC) in recent years. Despite its good local control, slow tumoral shrinkage and rapid recurrence compromise treatment outcomes. We evaluated the signal intensity of the hepatic parenchyma and tumours by using dynamic contrast enhanced magnetic resonance imaging (MRI) and correlated the findings with clinical outcomes. Nineteen patients with advanced HCC received 50 Gy in 25 fractions. They underwent a dynamic contrast-enhanced, turbo fast low-angle shot MR sequence at 1.5 T before therapy, at 2 weeks of therapy, and 1 month (week 9) later. Initial first-pass enhancement slopes (slope) and peak enhancement ratios (peak) were measured. RESULTS: Initial signal intensities were not associated with RT outcomes. An increased slope and peak of the tumour at week 2 was associated with an improved local response (P<0.05). In the parenchyma, an increased slope at week 2 was associated with recurrence outside the radiation fields or with progression over distant sites (P<0.05). The differences in signal changes at week 2 during RT were not persistent at a statistically significant level at 1 month after RT. CONCLUSION: Dynamic contrast-enhanced MRI signals may act as biomarkers for early prediction of responses to RT in patients with HCC. Signal intensities at week 2 are important in evaluating treatment outcomes.