Publications by authors named "Roger Santos"

Background: Lupus nephritis (LN) is the most common cause of kidney injury in systemic lupus erythematosus and associated with higher morbidity and mortality. Low medication adherence correlates with adverse clinical outcomes.

Methods: In a large, integrated health system at Kaiser Permanente East Bay Area, the authors identified mycophenolate mofetil (MMF) prescriptions for LN and collected patient demographics, medication adherence, and copay data.

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Aims: To evaluate the effects of testosterone on endothelium-dependent vasodilation and oxidative stress in mesenteric resistance arteries.

Main Methods: Spontaneously hypertensive rats (SHR), aged 8 to 10 weeks, were divided into four groups: intact (SHAM), intact treated with testosterone (TTO; 3 mg/kg/day) via subcutaneous route (s.c.

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The role of androgens in vascular reactivity is controversial, particularly regarding their age-related actions. The objective of this study was to conduct a temporal evaluation of the vascular reactivity of resistance arteries of young male rats, as well as to understand how male sex hormones can influence the vascular function of these animals. Endothelium-mediated relaxation was characterized in third-order mesenteric arteries of 10-, 12-, 16-, and 18w (week-old) male rats.

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Aim: Endothelial mechanisms underlying the vascular effects of estrogen modulated by the G protein-coupled estrogen receptor (GPER) are not well understood, especially in gonadal sex hormone deprivation. Thus, we investigated vascular function and endothelial signaling pathways involved in the selective activation of GPER in resistance arteries of gonadectomized rats.

Methods: Gonadectomy was performed in Wistar rats of both sexes.

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Background: The protective effect of estrogen on the vasculature cannot be explained only by its action through the receptors ERα and ERβ. G protein-coupled estrogen receptors (GPER)-which are widely distributed throughout the cardiovascular system-may also be involved in this response. However, little is known about GPER actions in hypertension.

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Objectives: The effect of oestrogen in hormonal dysfunction is not clear, especially in the coronary vascular bed. This study aimed at estradiol action (E2) in the coronary vascular bed from sham-operated and gonadectomized female and male spontaneously hypertensive rats (SHRs).

Methods: Male and female SHRs had their mean arterial pressure (MAP) and baseline coronary perfusion pressure (CPP) determined.

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Although progesterone has the ability to promote dilation of vascular smooth muscle, its role in coronary circulation is still poorly characterized, especially in essential hypertension and in a model of endogenous deficiency of ovarian hormones. Thus, this study evaluated the effect of progesterone treatment on endothelium-dependent coronary vascular reactivity in hypertensive (SHR) and ovariectomized rats. Adult SHR aged 8-10 weeks were divided into: SHAM, Ovariectomized (OVX) and Ovariectomized + treatment with 2 mg/kg/day of progesterone for 15 days (OVX-P4).

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Physiological or supraphysiological levels of testosterone appear to be associated with the development of risk factors for cardiovascular diseases such as hypertension, as this hormone modulates the release of endothelial factors. However, its actions are still controversial, especially in the coronary circulation of hypertensive animals. This study was designed to assess the effects of testosterone treatment (T) on endothelium-dependent coronary vascular reactivity in orchiectomized SHR.

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Diminazene aceturate (DIZE) has been described as an angiotensin-converting enzyme 2 (ACE2) activator. We aimed to investigate DIZE effects on blood pressure (BP) of spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats. BP was recorded in awake and unrestrained rats 24 hours after femoral artery catheterization.

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Cardiovascular effects induced by snake venoms, in spite of having a crucial role in the outcome of the envenomation, have been less studied than other toxic activities displayed by these venoms. In this study we evaluated acute cardiovascular responses to Bothrops leucurus venom - Bl-V - both in vivo, in anesthetized rats, and in vitro, in isolated rat mesenteric resistance arteries. Bl-V (10-100 μg protein/kg) caused dose-dependent hypotension, followed by gradual recovery (2-20 min) to basal levels, and induced dose-dependent (1-20 μg/mL) vasodilation in pre-contracted arteries, what was more pronounced when the endothelium remained intact.

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Background: Punica granatum L. is an infructescence native of occidental Asia and Mediterranean Europe, popularly referred to as pomegranate. It has been used in ethnomedicine for several applications, including the treatment of obesity, inflammation, diabetes, and the regulation of blood lipid parameters.

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Aim: Although progesterone (P4) has a beneficial effect on the cardiovascular system, P4 actions on the coronary bed have not yet been fully elucidated. This study evaluated the effect of progesterone treatment on endothelium-dependent coronary vascular reactivity in Wistar rats.

Main Methods: Eight-week-old adult rats were divided into Sham, Ovariectomized (OVX), Ovariectomized and progesterone treated (OVX P4).

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Progesterone seems to play a role in cardiovascular physiology since its receptors are expressed on endothelial cells from both sexes of mammals. However, little is known about its role on the coronary circulation. Thus, this study aims to evaluate the effect of acute administration of progesterone on the coronary bed and the endothelial pathways involved in this action in normotensive rats of both sexes.

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Aim: An imbalance between antioxidant and pro-oxidant factors, with a predominance of the latter, characterises oxidative stress and is indicative of a loss of vascular function. The beneficial vascular effects of oestrogen may be related to its ability to stimulate the G protein-coupled oestrogen receptor (GPER) and produce antioxidant activity. This study evaluated the GPER-dependent relaxation response in the mesenteric resistance arteries of female and male rats and measured the contributions of pro-oxidant and antioxidant enzymes in this response.

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PsaA (pneumococcal surface antigen A) is a S. pneumoniae virulence factor that belongs to the metal transport system. The Manganese PsaA binding has been associated with oxidative stress resistance becoming a pivotal element in the bacteria virulence.

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Compared with age-matched men, premenopausal women are largely protected from coronary artery disease, a difference that is lost after menopause. The effects of oestrogens are mediated by the activation of nuclear receptors (ERα and ERβ) and by the G protein-coupled oestrogen receptor (GPER). This study aims to evaluate the potential role of GPER in coronary circulation in female and male rats.

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Aim: The action of oestrogen has traditionally been attributed to the activation of nuclear receptors (ERα and ERβ). A third receptor, the G protein-coupled oestrogen receptor (GPER), has been described as mediator of the rapid action of oestrogen. Based on the possible protective role of oestrogen in the cardiovascular system, the present study was designed to determine whether selective GPER activation induces relaxation of mesenteric resistance arteries in both sexes and which signalling pathways are involved.

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Decline in estrogen levels promotes endothelial dysfunction and, consequently, the most prevalent cardiovascular diseases in menopausal women. The use of natural therapies such as pomegranate can change these results. Pomegranate [ (Punicaceae)] is widely used as a phytotherapeutic agent worldwide, including in Brazil.

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Based on the antioxidant properties of pomegranate, this study was designed to investigate the effects of pomegranate peel extract on damage associated with hypertension and aging in a spontaneously hypertensive rat (SHR) model. The influence of pomegranate consumption was examined on systolic blood pressure (SBP), angiotensin-converting enzyme (ACE) coronary activity, oxidative stress, and vascular morphology. Four- or 28-wk-old SHR model rats were treated for 30 d, with terminal experimental animal age being 8 and 32 wk, respectively, with either pomegranate extract (SHR-PG) or filtered water (SHR).

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Background: The understanding of obsesity-related vascular dysfunction remains controversial mainly because of the diseases associated with vascular injury. Exercise training is known to prevent vascular dysfunction. Using an obesity model without comorbidities, we aimed at investigating the underlying mechanism of vascular dysfunction and how exercise interferes with this process.

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The present study aimed to determine the effects of chronic treatment with different doses of testosterone on endothelium-dependent coronary vascular reactivity in male rats. Adult male rats were divided into four experimental groups: control (SHAM), castrated (CAST), castrated and immediately treated subcutaneously with a physiological dose (0.5 mg/kg/day, PHYSIO group) or supraphysiological dose (2.

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Gender-associated differences in the development of cardiovascular diseases have been described in humans and animals. These differences could explain the low incidence of cardiovascular disease in women in the reproductive period, such as stroke, hypertension, and atherosclerosis. The cardiovascular protection observed in females has been attributed to the beneficial effects of estrogen on endothelial function.

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The aim of this study was to evaluate the effects of swimming training (SW) and oestrogen replacement therapy (ERT) on coronary vascular reactivity and the expression of antioxidant enzymes in ovariectomized rats. Animals were randomly assigned to one of five groups: sham (SH), ovariectomized (OVX), ovariectomized with E2 (OE2), ovariectomized with exercise (OSW), and ovariectomized with E2 plus exercise (OE2+SW). The SW protocol (5×/week, 60 min/day) and/or ERT were conducted for 8 weeks; the vasodilator response to bradykinin was analysed (Langendorff Method), and the expression of antioxidant enzymes (SOD-1 and 2, catalase) and eNOS and iNOS were evaluated by Western blotting.

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Triorganotins, such as tributyltin (TBT), are environmental contaminants that are commonly used as antifouling agents for boats. However, TBT is also known to alter mammalian reproductive functions. Although the female sex hormones are primarily involved in the regulation of reproductive functions, 17β-estradiol also protects against cardiovascular diseases, in that this hormone reduces the incidence of coronary artery disease via coronary vasodilation.

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Several studies have demonstrated that gonadal hormones show significant effects on the brain and signaling pathways of effector organs/cells that respond to neurotransmitters. Since little information is available concerning the impact of male and female gonadal hormones on the renal and peripheral sympathetic system, the objective of this study was to further assess whether and how the renal content and plasma concentration of catecholamines are influenced by gender and the estrous cycle in rats. To achieve this, males Wistar rats were divided into 4 groups: (i) sham (i.

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