ATP-activated currents were studied in Leydig cells of mice with the patch-clamp technique. Whole cell currents were rapidly activating and slowly desensitizing (55% decrement from the peak value on exposure to 100 microM ATP for 60 s), requiring 3 min of washout to recover 100% of the response. The concentration-response relationships for ATP, adenosine 5'-O-(3-thiotriphosphate) (ATPgammaS), and 2-methylthio-ATP (2-MeS-ATP) were described by the Hill equation with a concentration evoking 50% of maximal ATP response (K(d)) of 44, 110, and 637 microM, respectively, and a Hill coefficient of 2. The order of efficacy of agonists was ATP >or= ATPgammaS > 2-MeS-ATP > 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP). alphabeta-Methylene-ATP (alphabeta-MeATP), GTP, UTP, cAMP, and adenosine were ineffective. Suramin and pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) blocked the responses in a concentration-dependent manner. The ATP-activated currents were dependent on extracellular pH, being maximal at pH 6.5 and decreasing with both acidification and alkalinization (apparent dissociation constant (pK(a)) of 5.9 and 7.4, respectively). The whole cell current-voltage relationship showed inward rectification and reversed near 0 mV. Experiments performed in bi-ionic conditions for measurement of reversal potentials showed that this channel is highly permeable to calcium [permeability (P)(Ca)/P(Na) = 5.32], but not to chloride (P(Cl)/P(Na) = 0.03) or N-methyl-D-glucamine (NMDG) (P(NMDG)/P(Na) = 0.09). Unitary currents recorded in outside-out patches had a chord conductance of 27 pS (between -90 and -50 mV) and were inward rectifying. The average current passing through the excised patch decreased with time [time constant (tau) = 13 s], resembling desensitization of the macroscopic current. These findings indicate that the ATP receptor present in Leydig cells shows properties most similar to those of cloned homomeric P2X(2).

Pharmacologic and intermittent pneumatic compression thromboembolic prophylaxis in 563 consecutives abdominoplasty cases Pharmacologic and intermittent pneumatic compression thromboembolic prophylaxis in 563 consecutives abdominoplasty cases Profilaxia tromboembólica farmacológica e por compressão pneumática intermitente em 563 casos consecutivos de abdominoplastia ABSTRACT Background: Abdominoplasty is a common cosmetic surgery and is subject to the same complications as any surgical procedure, including thromboembolic phenomena. The aim of this study was to assess the incidence of complications in consecutive abdominoplasties performed over a 3-year period, to identify risk factors for the complications, and to compare the efficacy of two protocols for prevention of thromboembolism. Methods: A retrospective study was conducted of 563 patients who underwent isolated abdominoplasty or abdominoplasty combined with additional cosmetic surgeries between March 2008 and April 2011. All patients received thromboembolism prophylaxis using either pharmacological (enoxaparin; 357 patients) or mechanical (intermittent pneumatic compression, IPC; 206 patients) protocols. Results: Of the 563 patients studied, 4 (0.7%) were male (0.7%) and 559 (99.3%) were female. The patients underwent isolated abdominoplasty (201; 35.7%) or abdominoplasty combined with other procedures (362; 64.3%). The patient groups receiving pharmacological and mechanical prophylaxis presented similar demographic and clinical characteristics and had similar risk factors for thromboembolic events. The incidence of complications in the patient groups undergoing pharmacological versus mechanical prophylaxis were: hematoma (5.6% vs. 10.7%), infection (2.2% vs. 2.4%), dehiscence (3.1% vs. 1.9%), seroma (2.2% vs. 2.4%), and deep vein thrombosis/pulmonary embolism (0.6% vs. 0.5%). There were no statistically significant differences in the incidence of complications between the two groups. Conclusion: The incidence of complications in 563 consecutive cases of abdominoplasty was similar to that reported in the literature. The pharmacological and mechanical protocols for thromboembolic prophylaxis in abdominoplasty were equally effective.

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As células de Leydig produzem e secretam testosterona, num processo controlado pelo Hormônio Luteinizante (LH) e modulado através de diversos fatores. O trifosfato de adenosina (ATP), no meio extracelular, tem se constituído num novo modulador do processo, atuando via ativação de receptores purinérgicos. Neste trabalho, a técnica de “patch-clamp” foi utilizada para detectar e caracterizar as correntes iônicas, induzidas pela ativação desses receptores, em células de Leydig, isoladas a fresco, de testículos de camundongos. A adição de ATP ao banho levou ao surgimento de uma corrente orientada para dentro, em potenciais hiperpolarizantes. A amplitude da corrente é dependente da dose de ATP, para cada nível de potencial aplicado à célula, e apresenta dessensibilização para doses acima de 60 m M. A relação corrente-voltagem é fortemente retificada na direção de potenciais hiperpolarizantes e apresenta um potencial de reversão próximo de zero mV, indicando uma via de baixa seletividade a cátions. Esses  resultados vêm confirmar a presença de receptores purinérgicos em células de Leydig, muito provavelmente pertencentes à família P2X.