Peak cardiac power output and cardiac reserve in sedentary men and women

Background and Purpose: Cardiac power output (CPO) and cardiac reserve (CR) are novel parameters of overall cardiac function. The purpose of this study was to determine differences in values of the CPO at rest and peak exercise and CR in sedentary men and women. Material and Methods: Thirty healthy men (age 21.2±0.7 years, body mass 63±6.3 kg, height 168.3±5.1 cm) and thirty healthy women (age 21.3±1.9 years, mass 82.5±7.9 kg, height 181.9±4.9 cm) were included in this study. Echocardiography was used to assess cardiac and hemodynamic parameters. CPO was calculated, at rest and after performed maximal bicycle test, as the product of cardiac output and mean arterial pressure, and CR as the difference of CPO value measured at peak exercise and at rest. Results: At rest, the two groups had similar values of cardiac power output (1.04±0.3W versus 1.14±0.25W, p>0.05). CPO after peak exercise was higher in men (5.1±0.72W versus 3.9±0.58W, p<0.05), as was cardiac reserve (3.96±0.64W versus 2.86±0.44W, p<0.05), respectively. After allometric scaling method was used to decrease the effect of body size on peak CPO, men still had significantly higher peak CPO (2.79±0.4 W m-2 versus 2.46±0.32 W m-2, p<0.05). At peak exercise, a significant positive relationship was found between cardiac power output and end diastolic volume (r=0.60), end diastolic left ventricular internal dimension (r=0.58), stroke volume (r=0.86) and cardiac output (r=0.87). Conclusion: The study showed that men had higher CPO after peak exercise and greater cardiac reserve than women, even after decreasing body size effect

Heart rate variability before and after cycle exercise in relation to different body positions

The purpose of this study was to assess the effect of three different body positions on HRV measures following short-term submaximal exercise. Thirty young healthy males performed submaximal cycling for five minutes on three different occasions. Measures of HRV were obtained from 5-min R to R wave intervals before the exercise (baseline) and during the last five minutes of a 15 min recovery (post-exercise) in three different body positions (seated, supine, supine with elevated legs). Measures of the mean RR normal-to-normal intervals (RRNN), the standard deviation of normal-to-normal intervals (SDNN), the root mean square of successive differences (RMSSD) and the low-frequency (LF) and the high-frequency (HF) spectral power were analyzed. Post-exercise RRNN, RMSSD were significantly higher in the two supine positions (p 0.05). Post-exercise time domain measures of HRV (RRNN, SDNN, RMSSD) were significantly lower compared with baseline values (p < 0.01) regardless body position. Post-exercise ln LF and ln HF in all three positions remained significantly reduced during recovery compared to baseline values (p < 0.01). The present study suggests that 15 minutes following short-term submaximal exercise most of the time and frequency domain HRV measures have not returned to pre-exercise values. Modifications in autonomic cardiac regulation induced by body posture present at rest remained after exercise, but the post-exercise differences among the three positions did not resemble the ones established at res

Small force metrology for AFM, stylus instruments, CMM and nanoindenter via reference springs and sensors

With the increasing spread of soft polymer products the calibration of probing forces of atomic force microscopes, stylus instruments, coordinate measuring machines and nanoindenters becomes more and more important in order not to scratch the surface of these products during quality control. New sensors and reference springs for force calibration and new calibration methods for these devices will be presented along with some comparison measurements revealing the status of force and stiffness calibration. The contribution closes with an outlook on the current status of probing force standardization

Advances in the treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future

Kalibrierung der Biegesteifigkeit von AFM-Cantilevern mit Kompensationswaagen

Der Beitrag beschreibt die Kalibrierung der Biegesteifigkeit von AFM Cantilevern mit der Messeinrichtung der PTB sowie eine Vergleichsmessung mit einer von der TU Ilmenau verbesserten Messeinrichtung, bei der die Auslenkungsmessung der Cantilever laserinterferometrisch erfolgt. Die erzielten Messunsicherheiten werden diskutiert

Systemic Lupus Erythematosus and Secondary Antiphospholipid Syndrome after Thymectomy for Myasthenia Gravis - A Case Report

INTRODUCTION: Systemic lupus erythematosus (SLE) and myasthenia gravis (MG) are autoimmune diseases that show some similarities: a higher incidence in young women, relapsing-remitting course and positive anti-nuclear antibodies (ANA). However, they are two different clinical syndromes, which can coexist or precede each other. Thymectomy is a therapeutic option for patients with severe MG or thymoma. There are many cases of SLE after thymectomy described in the literature, so the question arises whether thymectomy predisposes patients to SLE and what are imunopathogenetic mechanisms behind this process.CASE REPORT: We report a case of a patient who was diagnosed with SLE and secondary antiphospholipid syndrome (APS) 28 years after thymectomy for MG. Clinical picture of SLE was characterized by cutaneous and articular manifestations, polyserositis, lupus nephritis and immunological parameters showed positive ANA, anti-ds-DNA, excessive consumption of complement components, positive cryoglobulins. Clinical and laboratory immunological parameters for the diagnosis of secondary APS where also present. The patient was initially treated with glucocorticoids followed by mycophenolate mofetil. During one year follow-up patient was in a stable remission of SLE.CONCLUSION: Thymectomy for MG may predispose SLE development in some patients. Further studies are needed to better understand the connection between these two autoimmune diseases