Stage-specific analysis of plasma protein profiles in ovarian cancer: Difference in-gel electrophoresis analysis of pooled clinical samples.

INTRODUCTION: Ovarian cancer is the leading cause of death from gynecological cancer. Non-specific symptoms early in disease and the lack of specific biomarkers hinder early diagnosis. Multi-marker blood screening tests have shown promise for improving identification of early stage disease; however, available tests lack sensitivity, and specificity. MATERIALS AND METHODS: In this study, pooled deeply-depleted plasma from women with Stage 1, 2 or 3 ovarian cancer and healthy controls were used to compare the 2-dimensional gel electrophoresis (2-DE) protein profiles and identify potential novel markers of ovarian cancer progression. RESULTS/DISCUSSION: Stage-specific variation in biomarker expression was observed. For example, apolipoprotein A1 expression is relatively low in control and Stage 1, but shows a substantial increase in Stage 2 and 3, thus, potential of utility for disease confirmation rather than early detection. A better marker for early stage disease was tropomyosin 4 (TPM4). The expression of TPM4 increased by 2-fold in Stage 2 before returning to "normal" levels in Stage 3 disease. Multiple isoforms were also identified for some proteins and in some cases, displayed stage-specific expression. An interesting example was fibrinogen alpha, for which 8 isoforms were identified. Four displayed a moderate increase at Stage 1 and a substantial increase for Stages 2 and 3 while the other 4 showed only moderate increases. CONCLUSION: Herein is provided an improved summary of blood protein profiles for women with ovarian cancer stratified by stage.

Changes in passive tension after stretch of unexercised and eccentrically exercised human plantarflexor muscles.

The study measured the effect of stretch on passive mechanical properties in unexercised and eccentrically exercised plantarflexor muscles, to obtain insight into how stretch might serve athletes as a warm-up strategy. Passive torque, voluntary contraction strength and muscle soreness were measured before and after a large amplitude stretch given before and after a period of eccentric exercise and at 0, 1, 2 and 24 h later. Stretch of the unexercised muscle led to a 20% fall in passive torque which recovered within an hour. About 40% of the fall could be recovered immediately with a voluntary contraction. After eccentric exercise there was a rise in passive torque by 20% at 2 h post-exercise. This rise was postulated to result from an injury contracture in muscle fibres damaged by the exercise. It was accompanied by a fall in maximum voluntary torque and the development of muscle soreness at 24 h. Stretch of the exercised muscle led to a fall in passive torque and rise in pain threshold. It is proposed that in response to a stretch there is a fall in passive tension in the muscle due to stable cross-bridges in sarcomeres which could be recovered with a voluntary contraction and an additional component attributable to the elastic filament, titin. The size of the fall was not significantly different between exercised and unexercised muscle. These observations provide a physiological basis for the effects of passive stretches on skeletal muscle and help to explain why they are used as a popular warm-up strategy.

Warm-up stretches reduce sensations of stiffness and soreness after eccentric exercise.

PURPOSE: A commonly used method for warm-up before exercise is to stretch muscles. How this benefits performance remains uncertain. After a period of eccentric exercise, there is muscle damage accompanied by an increase in passive tension, perceived as a sensation of increased stiffness in the exercised muscles. We have tested the idea that warm-up stretches might reduce levels of passive tension to reduce sensations of stiffness and soreness after eccentric exercise. METHODS: Subjects eccentrically exercised elbow flexors of one arm on an isokinetic dynamometer. The other arm acted as a control. After the exercise, measurements were made of resting elbow angle, as an indication of passive tension levels, before and after one or five large, passive arm extensions. Additional measurements made at 24 h included soreness levels in response to muscle stretch or vibration. RESULTS: After the exercise, the relaxed elbow adopted a more flexed posture than normal, an effect that slowly subsided over the next 4 d. Five rapid arm extensions returned arm posture back to near control levels. The flexed posture then gradually re-developed over the next hour. At 24 h postexercise, extending the arm produced some soreness as did muscle vibration. The pain from arm extension and vibration was reduced after a series of arm extensions. CONCLUSIONS: The flexed posture at the elbow is due to an increase in passive tension in elbow flexors as a result of muscle damage from the eccentric exercise. Stretch reduces passive tension. Benefits from the lower tension are reduced sensations of stiffness and soreness. This represents a new proposal for the mechanism for passive stretches as a warm-up strategy.

Peptidomic profiles of post myocardial infarction rats affinity depleted plasma using matrix-assisted laser desorption/ionization time of flight (MALDI-ToF) mass spectrometry.

BACKGROUND: Despite major advances in drug development, effective cardiovascular therapies and suitable cardiovascular biomarkers remain limited. The aim of this study was to leverage mass spectrometry (MS) based peptide profiling strategies to identify changes that occur in peptidomic profiles of rat plasma following coronary artery ligation generated myocardial infarction (MI). METHODS: One week after MI, rats were randomized to receive either an ACE inhibitor (ramipril, Ram-1 mg/kg/day), or vehicle (Veh) for 12 weeks. Echocardiography and hemodynamic measurements were made before sacrifice and plasma collection. High abundance proteins were depleted with affinity capture before MS profiling. Differentially expressed peptide ions were identified using proprietary software (ClinProtTools). RESULTS: MI increased heart/body weight (18%), lung/body weight (56%), and left ventricular (LV) end diastolic pressure (LVEDP, 247%); and significantly reduced percentage fractional shortening (FS, 75%) and rate of pressure rise in the LV (dP/dtmax, 20%). Ram treatment significantly attenuated the changes in LVEDP (61%) and FS (27%). Analysis of MALDI-ToF generated mass spectra demonstrated that peptide ions 1271, 1878, 1955, 2041 and 2254 m/z were consistently decreased by Ram treatment (p < 0.001) and thus may be associated with the agent's therapeutic effects. Among peptides that were significantly changed, synapsin-2, adenomatous polyposis coli protein and transcription factor jun-D were identified as significantly reduced by Ram treatment. CONCLUSIONS: This approach allows us to screen for potential biomarkers in a window of the blood proteome that previously has been difficult to access. The data obtained from such an approach may potentially useful in prognosis, diagnosis, and monitoring of treatment response.

Identification of ovarian cancer-associated proteins in symptomatic women: A novel method for semi-quantitative plasma proteomics.

PURPOSE: To evaluate the utility of an enhanced biomarker discovery approach in order to identify potential biomarkers relevant to ovarian cancer detection. EXPERIMENTAL DESIGN: We combined immuno-depletion, liquid-phase IEF, 1D-DIGE, MALDI-TOF/MS and LC-MS/MS to identify differentially expressed proteins in the plasma of symptomatic ovarian cancer patients, stratified by stage, compared to samples obtained from normal subjects. RESULTS: We demonstrate that this approach is a practical alternative to traditional 2D gel techniques and that it has some advantages, most notably increased protein capacity. Proteins were identified in all 76 bands excised from the gels in this project and confirmed the cancer-associated expression of several well-established biomarkers of ovarian cancer. These included C-reactive protein (CRP), haptoglobin, alpha-2 macroglobulin and A1A2. We also identified new ovarian cancer candidate biomarkers, Protein S100-A9 (S100A9) and multimerin-2. The cancer-associated differential expression of CRP and S100A9 was further confirmed by Western blot and ELISA. CONCLUSIONS: The methods developed in this study allow for the increased loading of plasma proteins into the analytical stream when compared to traditional 2D-DIGE. This increased protein identification sensitivity allowed us to identify new putative ovarian cancer biomarkers.