Surface-enhanced Raman spectral biomarkers correlate with Ankle Brachial Index and characterize leg muscle biochemical composition of patients with peripheral arterial disease

Peripheral arterial disease (PAD) is characterized by atherosclerotic blockages of the arteries supplying the lower extremities, which cause a progressive accumulation of ischemic injury to the skeletal muscles of the lower limbs. This injury includes altered metabolic processes, damaged organelles, and compromised bioenergetics in the affected muscles. The objective of this study was to explore the association of Raman spectral signatures of muscle biochemistry with the severity of atherosclerosis in the legs as determined by the Ankle Brachial Index (ABI) and clinical presentation. We collected muscle biopsies from the gastrocnemius (calf muscle) of five patients with clinically diagnosed claudication, five patients with clinically diagnosed critical limb ischemia (CLI), and five control patients who did not have PAD. A partial least squares regression (PLSR) model was able to predict patient ABI with a correlation coefficient of 0.99 during training and a correlation coefficient of 0.85 using a full cross-validation. When using the first three PLS factor scores in combination with linear discriminant analysis, the discriminant model was able to correctly classify the control, claudicating, and CLI patients with 100% accuracy, using a full cross-validation procedure. Raman spectroscopy is capable of detecting and measuring unique biochemical signatures of skeletal muscle. These signatures can discriminate control muscles from PAD muscles and correlate with the ABI and clinical presentation of the PAD patient. Raman spectroscopy provides novel spectral biomarkers that may complement existing methods for diagnosis and monitoring treatment of PAD patients

Temperature and velocity measurements of a rising thermal plume

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 16 (2015): 579–599, doi:10.1002/2014GC005576.The three-dimensional velocity and temperature fields surrounding an isolated thermal plume in a fluid with temperature-dependent viscosity are measured using Particle-Image Velocimetry and thermochromatic liquid crystals, respectively. The experimental conditions are relevant to a plume rising through the mantle. It is shown that while the velocity and the isotherm surrounding the plume can be used to visualize the plume, they do not reveal the finer details of its structure. However, by computing the Finite-Time Lyapunov Exponent fields from the velocity measurements, the material lines of the flow can be found, which clearly identify the shape of the plume head and characterize the behavior of the flow along the plume stem. It is shown that the vast majority of the material in the plume head has undergone significant stretching and originates from a wide region very low in the fluid domain, which is proposed as a contributing factor to the small-scale isotopic variability observed in ocean-island basalt regions. Lastly, the Finite-Time Lyapunov Exponent fields are used to calculate the steady state rise velocity of the thermal plume, which is found to scale linearly with the Rayleigh number, in contrast to some previous work. The possible cause and the significance of these conflicting results are discussed, and it is suggested that the scaling relationship may be affected by the temperature-dependence of the fluid viscosity in the current work.This work was funded by the National Science Foundation (grant EAR-055199) and the MAPS Dean's Office at UCL.2015-09-0

Surface-enhanced Raman spectral biomarkers correlate with Ankle Brachial Index and characterize leg muscle biochemical composition of patients with peripheral arterial disease

Peripheral arterial disease (PAD) is characterized by atherosclerotic blockages of the arteries supplying the lower extremities, which cause a progressive accumulation of ischemic injury to the skeletal muscles of the lower limbs. This injury includes altered metabolic processes, damaged organelles, and compromised bioenergetics in the affected muscles. The objective of this study was to explore the association of Raman spectral signatures of muscle biochemistry with the severity of atherosclerosis in the legs as determined by the Ankle Brachial Index (ABI) and clinical presentation. We collected muscle biopsies from the gastrocnemius (calf muscle) of five patients with clinically diagnosed claudication, five patients with clinically diagnosed critical limb ischemia (CLI), and five control patients who did not have PAD. A partial least squares regression (PLSR) model was able to predict patient ABI with a correlation coefficient of 0.99 during training and a correlation coefficient of 0.85 using a full cross-validation. When using the first three PLS factor scores in combination with linear discriminant analysis, the discriminant model was able to correctly classify the control, claudicating, and CLI patients with 100% accuracy, using a full cross-validation procedure. Raman spectroscopy is capable of detecting and measuring unique biochemical signatures of skeletal muscle. These signatures can discriminate control muscles from PAD muscles and correlate with the ABI and clinical presentation of the PAD patient. Raman spectroscopy provides novel spectral biomarkers that may complement existing methods for diagnosis and monitoring treatment of PAD patients

Predictive factors of developing diabetes mellitus in women with gestational diabetes.

BACKGROUND: To investigate which factors during gestational diabetes pregnancies correlate with the risk of developing impaired glucose tolerance or diabetes 1 year postpartum and to compare this risk in women with gestational diabetes and women with a normal oral glucose tolerance test during pregnancy. METHODS: Of 315 women with gestational diabetes, defined as a 2-hr blood glucose value of at least 9.0 mmol/l at a 75-g oral glucose tolerance test, who delivered in Lund 1991-99, 229 (73%) performed a new test 1 year postpartum. We compared maternal and fetal factors during pregnancy with the test value at follow up. A control group of 153 women with a 2-hr test value below 7.8 mmol/l during pregnancy were invited to a new test 1 year postpartum and 60 (39%) accepted. RESULTS: At 1 year follow up, 31% of the women with gestational diabetes but only one of the 60 controls showed pathologic glucose tolerance and one had developed diabetes. The following factors in women with gestational diabetes were identified as predicting impaired glucose tolerance or diabetes at 1 year follow up: maternal age over 40 and--in a multiple regression analysis, independent of each other--a high 2-hr value at oral glucose tolerance test during pregnancy and insulin treatment during pregnancy. CONCLUSION: The risk of developing manifest diabetes after gestational diabetes may be high enough to justify a general screening or diagnostic procedure in all pregnant women to identify women with gestational diabetes and a postpartum follow up program for them. This study did not identify any particular factor during pregnancy with enough precision to predict a later progression to diabetes

Muscle mass, quality, and strength; physical function and activity; and metabolic status in cachectic patients with head and neck cancer

Background & aims: Cancer cachexia is commonly associated with poor prognosis in patients with head and neck cancer (HNC). However, its pathophysiology and treatment are not well established. The current study aimed to assess the muscle mass/quality/strength, physical function and activity, resting energy expenditure (REE), and respiratory quotient (RQ) in cachectic patients with HNC. Methods: This prospective cross-sectional study analyzed 64 patients with HNC. Body composition was measured via direct segmental multifrequency bioelectrical impedance analysis, and muscle quality was assessed using echo intensity on ultrasonography images. Muscle strength was investigated utilizing handgrip strength and isometric knee extension force (IKEF). Physical function was evaluated using the 10-mwalking speed test and the five times sit-to-stand (5-STS) test. Physical activity was examined using a wearable triaxial accelerometer. REE and RQ were measured via indirect calorimetry. These parameters were compared between the cachectic and noncachectic groups. Results: In total, 23 (36%) patients were diagnosed with cachexia. The cachectic group had a significantly lower muscle mass than the noncachectic group. Nevertheless, there was no significant difference in terms of fat between the two groups. The cachectic group had a higher quadriceps echo intensity and a lower handgrip strength and IKEF than the noncachectic group. Moreover, they had a significantly slower normal and maximum walking speed and 5 STS speed. The number of steps, total activity time, and time of activity (<3 Mets) did not significantly differ between the two groups. The cachectic group had a shorter time of activity (≥3 Mets) than the noncachectic group. Furthermore, the cachectic group had a significantly higher REE/body weight and REE/fat free mass and a significantly lower RQ than the noncachectic group. Conclusions: The cachectic group had a lower muscle mass/quality/strength and physical function and activity and a higher REE than the noncachectic group. Thus, REE and physical activity should be evaluated to determine energy requirements. The RQ was lower in the cachectic group than that in the noncachectic group, indicating changes in energy substrate. Further studies must be conducted to examine effective nutritional and exercise interventions for patients with cancer cachexia

One-year cardiovascular outcomes of drug-eluting stent versus bare-metal stent implanted in diabetic patients with acute coronary syndrome

AbstractBackgroundThe outcomes of drug-eluting stent (DES) versus bare-metal stent (BMS) use in patients with diabetic mellitus (DM) and acute coronary syndrome (ACS) are rarely reported in Taiwan. This study aimed to investigate the 1-year cardiovascular outcomes of DESs versus BMSs implanted in Taiwanese patients with DM and ACS.MethodsFor this study, we collected and analyzed patient information from the database of the Taiwan ACS Full Spectrum registry regarding characteristics and cardiovascular events in participants with DM and ACS who received implantation of either BMS (BMS group) or DES (DES group) from October 2008 to January 2010.ResultsWe found that several characteristics significantly varied between the groups. Compared with the BMS group (n = 575), the DES group (n = 199) had significantly lower rates of in-hospital cardiogenic shock (1.5% vs. 4.9%, p = 0.037) and acute renal failure (0.5% vs. 4.5%, p = 0.008), all-cause mortality (5.0% vs. 8.9%, p = 0.048), and major adverse cardiac events (MACEs) at 1 year (11.1% vs. 18.6%, p = 0.006) with an identical target vessel revascularization (TVR) rate (6.0% vs. 7.3%, p = 0.395). The BMS group had significantly higher risk-adjusted all-cause mortality [hazard ratio (HR) = 2.4, 95% confidence interval (CI) 1.0–5.7; p = 0.048] and MACE (HR = 2.2, 95% CI 1.2–3.9; p = 0.011) at 1 year with identical risks of TVR (HR = 1.3, 95% CI 0.6–2.9; p = 0.505) and nonfatal myocardial infarction (HR = 1.5, 95% CI 0.5–4.4; p = 0.478).ConclusionThe results of this study support the use of DES over BMS in Taiwanese patients with DM and ACS, providing the clinical benefits of lower rates of total mortality and MACE, and without increased TVR at 1 year in a real-world setting

Lower limb revascularization leads to faster walking but with less efficient mechanics in claudicating patients

Peripheral artery disease (PAD) is characterized by reduced blood flow to the extremities due to atherosclerosis. Studies report impaired gait mechanics in patients with lower extremity PAD. We hypothesized that revascularization surgery would improve gait mechanics when quantified by net lower limb joint work across the stance phase of walking. We performed gait analyses in 35 patients with PAD and 35 healthy, older adults. Patients with PAD performed a walking protocol prior to and six months following revascularization surgery. Healthy adults only took part in a single walking session. Lower limb joint powers were calculated using inverse dynamics and were integrated across early, middle, and late stance phases to determine the work performed during each phase (J kg−1). The work mechanical ratio between positive-producing and negative-producing phases of stance was calculated for each lower-limb joint. Self-selected walking speed significantly increased from 1.13 ± 0.2 ms−1 to 1.26 ± 0.18 ms−1 in patients following revascularization (p \u3c 0.001). We observed a significant decrease in positive late stance work (p \u3c 0.001) in conjunction with more negative work during early stance (p \u3c 0.001) in patients following revascularization. Revascularization surgery led to faster walking without an increase in the ankle joint’s mechanical ratio. Our results suggest faster walking was achieved via work done at the hip rather than the ankle. These findings suggest that additional therapies that facilitate the restoration of muscle, tissue, and nervous system damage caused by years of having reduced blood flow to the limbs might still be beneficial following revascularization

Mitochondrial function assessed by 31P MRS and BOLD MRI in non-obese type 2 diabetic rats

The study aims to characterize age‐associated changes in skeletal muscle bioenergetics by evaluating the response to ischemia‐reperfusion in the skeletal muscle of the Goto‐Kakizaki (GK) rats, a rat model of non‐obese type 2 diabetes (T2D). 31P magnetic resonance spectroscopy (MRS) and blood oxygen level‐dependent (BOLD) MRI was performed on the hindlimb of young (12 weeks) and adult (20 weeks) GK and Wistar (control) rats. 31P‐MRS and BOLD‐MRI data were acquired continuously during an ischemia and reperfusion protocol to quantify changes in phosphate metabolites and muscle oxygenation. The time constant of phosphocreatine recovery, an index of mitochondrial oxidative capacity, was not statistically different between GK rats (60.8 ± 13.9 sec in young group, 83.7 ± 13.0 sec in adult group) and their age‐matched controls (62.4 ± 11.6 sec in young group, 77.5 ± 7.1 sec in adult group). During ischemia, baseline‐normalized BOLD‐MRI signal was significantly lower in GK rats than in their age‐matched controls. These results suggest that insulin resistance leads to alterations in tissue metabolism without impaired mitochondrial oxidative capacity in GK rats