Publications by authors named "Andre A Schenka"

Human seminal vesicles present basal release of epithelium-derived 6-nitrodopamine (6-ND) and this catecholamine potentiates noradrenaline-induced contractions. Since nitric oxide synthase (NOS) activation is a determining factor involved in 6-ND biosynthesis, this study aimed to investigate which NOS isoform is responsible for the 6-ND release in mouse isolated seminal vesicles (MISV). Male control, eNOS, NOS, iNOS, and e/n/iNOS mice were used.

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Rat isolated atria and ventricles release endothelium-derived 6-nitrodopamine, which induces potent positive chronotropic and inotropic responses. 6-Cyanodopamine is released from rabbit isolated atria and ventricles; however, it is not known whether this novel catecholamine has any action on the isolated heart. Therefore, it was investigated whether rat isolated ventricles release 6-cyanodopamine and its action on the rat isolated heart.

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6-Nitrodopamine (6-ND) is the main catecholamine released from human isolated vas deferens and the adrenergic nervous system is known to play a major role in the contractions of the epididymal portion of the vas deferens. Here it was investigated the interactions of 6-ND on the contractions of the human isolated vas deferens induced by either classical catecholamines or electric-field stimulation (EFS). The vas deferens obtained from 106 patients who underwent vasectomy surgery were mounted in a 10-mL glass chamber filled with warmed (37°C) and oxygenated Krebs-Henseleit's solution.

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Background: 6-Nitrodopamine (6-ND) released from rat vas deferens acts an endogenous modulator of vas deferens contractility.

Objectives: To investigate whether rat isolated seminal vesicles (RISV) releases 6-ND, the mechanisms involved in the release, and the modulatory role of 6-ND on tissue contractility.

Methods: Rat seminal vesicles were removed and placed in Krebs-Henseleit's solution at 37°C for 30 min, and an aliquot was used to analyze the concentrations of 6-ND, dopamine, noradrenaline, and adrenaline by liquid chromatography with tandem mass spectrometry (LC-MS/MS).

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Mammalian and reptilian vascular tissues present basal release of 6-nitrodopamine, which is reduced when the tissues are pre-incubated with the NO synthase inhibitor L-N-Nitro arginine methyl ester (L-NAME), or when the endothelium is mechanically removed. 6-Nitrodopamine induces vasorelaxation in pre-contracted vascular rings by antagonizing the dopaminergic D receptor. Here it was investigated whether male swine vessels (including carotid, left descendent coronary, renal, and femoral arteries) release 6-nitrodopamine, dopamine, noradrenaline, and adrenaline, as measured by liquid chromatography coupled to tandem mass spectrometry.

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6-Cyanodopamine is a novel catecholamine released from rabbit isolated heart. However, it is not known whether this catecholamine presents any biological activity. Here, it was evaluated whether 6-cyanodopamine (6-CYD) is released from rat vas deferens and its effect on this tissue contractility.

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Multidrug resistance proteins type 4 (MRP4) and 5 (MRP5) play pivotal roles in the transport of cyclic nucleotides in various tissues. However, their specific functions within the lower urinary tract remain relatively unexplored. This study aimed to investigate the effect of pharmacological inhibition of MRPs on cyclic nucleotide signaling in isolated pig bladder.

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Aims: To evaluate the basal release of 6-nitrodopamine (6-ND) from human isolated seminal vesicles (HISV) and to characterize its action and origin.

Main Methods: Left HISV obtained from patients undergoing prostatectomy surgery was suspended in a 3-mL organ bath containing warmed (37 °C) and gassed (95%O:5%CO) Krebs-Henseleit's solution (KHS) with ascorbic acid. An aliquot of 2 mL of the supernatant was used to quantify catecholamines by LC-MS/MS.

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We present a patient referred for investigation of adrenal insufficiency, confirmed due to disseminated paracoccidioidomycosis (PCM), with abdominal and central nervous system (CNS) involvement. Establishing the pathogenesis and immunological processes involved in chronic or latent infections by PCM has been challenging. Medical doctors caring for patients with immunodeficiencies should learn about these fungal infections to properly guide travel planning and have this possibility in the diagnostic arsenal when the patient returns from endemic areas.

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6-Nitrodopamine (6-ND) is a novel catecholamine that is released from human umbilical cord vessels, and it causes vascular relaxation by acting as a dopamine D-receptor antagonist. Here it was investigated whether human peripheral vessels obtained from patients who have undergone surgery for leg amputation release 6-ND, and its action in these tissues. Popliteal artery and vein strips present basal release of 6-ND, as measured by liquid chromatography coupled to tandem mass spectrometry.

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Article Synopsis
  • Magnetic nanoparticles (MNps) have promising applications in biomedicine, such as drug delivery and MRI imaging, but their safety and potential toxicity remain under-researched due to varying surface modifications.
  • The study focused on synthesizing citrate-coated magnetite nanoparticles (IONps) and assessed their toxic effects using both in vitro and in vivo models, finding that they did not significantly impact cell viability or cause adverse effects in animal testing.
  • Despite a slight increase in iron levels in the liver, the nanoparticles demonstrated a simple and effective production method, showing potential as safe and effective drug delivery systems.
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6-Nitrodopamine (6-ND) is a novel catecholamine that is released from human umbilical cord vessels and Chelonoidis carbonaria aortic rings. The synthesis/release of 6-ND is inhibited by either pre-incubation of the vessels with the nitric oxide (NO) synthase inhibitor L-NAME or by mechanical removal of the endothelium. 6-ND causes powerful vasorelaxation, acting as a potent and selective dopamine D-like receptor antagonist.

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The contractions of aortic rings induced by electrical field stimulation (EFS) are not inhibited by blockade of the voltage-gated sodium channels by tetrodotoxin but almost abolished by the α1/α2-adrenoceptor antagonist phentolamine. The objective of this study was to identify the mediator(s) responsible for the EFS-induced contractions of aortic rings. Each ring was suspended between two wire hooks and mounted in isolated 10 ml organ chambers filled with oxygenated and heated Krebs-Henseleit's solution.

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Inflammatory arthritis, such as rheumatoid arthritis (RA), stands out as one of the main sources of pain and impairment to the quality of life. The use of hemopressin (PVNFKFLSH; Hp), an inverse agonist of type 1 cannabinoid receptor, has proven to be effective in producing analgesia in pain models, but its effect on neuro-inflammatory aspects of RA is limited. In this study, antigen-induced arthritis (AIA) was evoked by the intraarticular (i.

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Electrical field stimulation (EFS) induces contractions of both snake aorta and human umbilical cord vessels (HUCV) which were dependent on the presence of the endothelium. This study aimed to establish the nature of the mediator(s) responsible for EFS-induced contractions in HUCV. Rings with or without endothelium from human umbilical artery (HUA) or vein (HUV) were mounted in organ bath chambers containing oxygenated, heated Krebs-Henseleit's solution.

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The role of endothelium in the electrical-field stimulation (EFS)-induced contractions of Chelonoidis carbonaria aorta was investigated. Contractions were evaluated in the presence and absence of L-NAME (100 μM), tetrodotoxin (1 μM), phentolamine (10 and 100 μM), phenoxybenzamine (1 and 10 μM), prazosin (100 μM), idazoxan (100 μM), atropine (10 μM), D-tubocurarine (10 μM) or indomethacin (10 μM). EFS-induced contraction was also carried out in endothelium-denuded rings.

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We describe here an angiomyomatous hamartoma in the right axillary lymph node of a three-year-old male cynomolgus monkey ( Macaca fascicularis), used as a control subject in a short-term toxicity study. This is a very rare lesion that has been reported almost exclusively in inguinal lymph nodes, and to date only in human beings. In the present case, light microscopy revealed partial replacement of the lymph node parenchyma by a disorganized, irregular vascular network, sparsely distributed smooth muscle cells, and a fibro-adipocytic stroma.

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Epilepsy is a common disease presenting with recurrent seizures. Hippocampal sclerosis (HS) is the commonest histopathological alteration in patients with temporal lobe epilepsy (TLE) undergoing surgery. HS physiopathogenesis is debatable.

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Endothelium is the main source of catecholamine release in the electrical-field stimulation (EFS)-induced aortic contractions of the non- venomous snake Panterophis guttatus. However, adrenergic vasomotor control in venomous snakes such as Crotalus durissus terrificus and Bothrops jararaca has not yet been investigated. Crotalus and Bothrops aortic rings were mounted in an organ bath system.

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Introduction: Experimental evidences from the last 2 decades supports the existence of a special type of neoplastic cell with stem-like features [cancer stem cell (CSC)] and their role in the pathophysiology and therapeutic resistance of breast cancer. However, their clinical value in human breast cancer has not been fully determined.

Materials And Methods: An immunohistochemistry panel of 10 putative CSC markers (CD34, C-KIT, CD10, SOX-2, OCT 3/4, p63, CD24, CD44, CD133, and ESA/EPCAM) was applied to 74 cases of breast cancer, followed in a Regional Cancer Center of Minas Gerais State, Brazil, from 2004 to 2006.

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The present review is focused on the current role of neoplastic stem and progenitor-like cells as primary targets in the pharmacotherapy of cancer as well as in the development of new anticancer drugs. We begin by summarizing the main characteristics of these tumor-initiating cells and key concepts that support their participation in therapeutic failure. In particular, we discuss the differences between the major carcinogenesis models (ie, clonal evolution vs cancer stem cell (CSC) model) with emphasis on breast cancer (given its importance to the study of CSCs) and their implications for the development of new treatment strategies.

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Simvastatin, a competitive inhibitor of HMG-CoA reductase widely used in the treatment and prevention of hyperlipidemia-related diseases, has recently been associated to in vitro anticancer stem cell (CSC) actions. However, these effects have not been confirmed in vivo. To assess in vivo anti-CSC effects of simvastatin, female Sprague-Dawley rats with 7,12-dimethyl-benz(a)anthracene (DMBA)-induced mammary cancer and control animals were treated for 14 days with either simvastatin (20 or 40 mg/kg/day) or soybean oil (N = 60).

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Background: Adhesions may increase the incidence of lethal complications of cardiac reoperations, which account for up to 20% of all open-heart surgeries. Herein, we describe the use of a polyvinyl alcohol membrane (PVAM) as a pericardial alternative and describe its performance during reoperation in a relevant animal model.

Methods: The PVAM samples were reticulated by electron beam radiation and manipulated into a tube shape.

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