A time-resolved fluorescence immunoassay for the measurement of testosterone in saliva: Monitoring of testosterone replacement therapy with testosterone buciclate

Monitoring of testosterone replacement therapy requires a reliable method for testosterone measurement. Determination of salivary testosterone, which reflects the hormone's biologically active plasma fraction, is a superior technique for this purpose. The aim of the present study was to establish a new sensitive time-resolved fluorescence immunoassay for the accurate measurement of testosterone levels in saliva and to validate it by monitoring testosterone replacement therapy in eight hypogonadal men. A clinical phase I- study with the new ester testosterone buciclate was performed to search for new testosterone preparations to produce constant serum levels in the therapy of male hypogonadism. After two control examinations eight male patients with primary hypogonadism were randomly assigned to two treatment groups (n = 2x4) and given single doses of either 200 mg (group I) or 600 mg (group II) testosterone buciclate intramuscularly. Saliva and blood samples were obtained 1, 2, 3, 5 and 7 days post injection and then weekly for three months. The time-resolved fluorescence immunoassay for salivary testosterone shows a detection limit of 16 pmol/l, an intra-assay CV of 8.9% (at a testosterone concentration of 302 pmol/l), an inter-assay CV of 8.7% (at a testosterone concentration of 305 pmol/l) and a good correlation with an established radioimmunsassay of r = 0.89. The sample volume required by this method is only 180 mu l for extraction and duplicate determination. The assay procedure requires no more than three hours. In group I (200 mg) testosterone did not increase to normal levels either in saliva or in serum. However, in group II, androgen levels increased significantly and were maintained in the normal range for up to 12 weeks with maximal salivary testosterone levels of 303 +/- 18 pmol/l (mean+/-SE) and maximal testosterone levels of 13.1 +/- 0.9 nmol/l (mean+/-SE) in serum in study week 6 and 7. The time-resolved fluorescence immunoassay for salivary testosterone provides a useful tool for monitoring androgen status in men and women and is well suited for the follow-up of testosterone replacement therapy on an outpatient basis. The long-acting ester testosterone buciclate is a promising agent for substitution therapy of male hypogonadism and in combination with testosterone monitoring in saliva offers an interesting new perspective for male contraception

Позиционный электропривод механизма перемещения

Объектом исследования является позиционный асинхронный электропривод механизма горизонтального перемещения груза. Цель работы – исследовать основные характеристики асинхронного электропривода с трехконтурной системой управления положением вала двигателя. В процессе исследования проводились выбор асинхронного двигателя для механизма перемещения, расчет параметров двигателя, его статических и динамических характеристик, выбор преобразователя частоты, синтез трехконтурной системы управления следящим электроприводом на базе регулируемого с векторным управлением.The object of the study is a positional asynchronous electric drive mechanism for the horizontal movement of cargo. The purpose of the work is to investigate the basic characteristics of an asynchronous electric drive with a three-circuit control system for positioning the motor shaft. In the process of research, the choice of an asynchronous motor for the displacement mechanism, calculation of the engine parameters, its static and dynamic characteristics, choice of a frequency converter, synthesis of a three-circuit control system for a servomotor drive based on an adjustable vector control were made

Enhanced glucocorticoid sensitivity in patients with chronic fatigue syndrome

Objective:  Alterations of the immune–neuroendocrine interplay have been described in chronic fatigue syndrome (CFS). Employing a recently developed method, the study set out to investigate whether patients with CFS have an altered sensitivity to glucocorticoids (GCs) when under stress. Methods:  A total of 21 CFS patients and 20 healthy age- and gender-matched controls underwent a standardized psychosocial stress test (Trier Social Stress Test, TSST). Salivary and plasma cortisol levels were measured repeatedly following exposure to the stressor. GC sensitivity was assessed in vitro by dexamethasone inhibition of lipopolysaccharide-stimulated production of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNC-α). Results:  Cortisol responses following the TSST did not differ significantly between CFS patients and healthy controls. GC sensitivity differed significantly between CFS patients and healthy controls, with CFS patients showing a greater sensitivity towards GCs (TNF-α: F1/39 = 7.32, P = 0.01; IL-6: F1/39 = 9.73, P = 0.004). Conclusion:  Consistent with recent evidence, CFS patients are characterized by an enhanced sensitivity to glucocorticoids. The implications for secondary processes, such as the regulatory influence of glucocorticoids on immune processes, are discussed

Endocrine stress responses in chronic fatigue syndrome

Subtle alterations of the hypothalamic-pituitary-adrenal (HPA) axis in chronic fatigue syndrome (CFS) have been proposed as a shared pathway linking numerous etiological and perpetuating processes with symptoms and observed physiological abnormalities. Because the HPA axis is involved in the adaptive responses to stress and CFS patients experience a worsening of symptoms after physical and psychological stress, we tested HPA axis functioning with three centrally acting stress tests. We employed two procedures mimicking real life stressors and compared them with a standardized pharmacological neuroendocrine challenge test. A total of 21 CFS patients were compared with 25 healthy controls regarding their cardiovascular and endocrine reactivity in a psychosocial stress test and a standardized exercise test and their endocrine response in the insulin tolerance test (ITT). Controlling for possible confounding variables, we found significantly lower ACTH responses in the psychosocial stress test, the exercise test and in the ITT, with no differences in plasma total cortisol responses. In all tests, CFS patients had significantly reduced basal ACTH levels. Cardiovascular responses were not significantly different between the groups in the psychosocial stress test and the exercise test. These results suggest that CFS patients are capable of mounting a sufficient cortisol response under different types of stress, but that on a central level subtle dysregulations of the HPA axis exist. Interestingly, the observed extent of the endocrine alterations was significantly associated with the duration of the syndrome. A postulated deficient hypothalamic CRH secretion could serve as a neuroendocrine substrate of the observed fatigue and pain symptomatology in CFS. Furthermore, these endocrine alterations could be secondary to chronicity of the syndrome