The molecular mechanism via which keratinocyte differentiation assembles multiple layers of cells (stratification) is poorly understood. We describe here a novel function of the Rho family member RhoE as a regulator of epidermal morphogenesis. RhoE protein levels are specifically and transiently up-regulated upon keratinocyte differentiation.
View Article and Find Full Text PDFPeripheral chemoreceptors located in the carotid bodies are the primary sensors of systemic hypoxia. Although the pattern of responses elicited by peripheral chemoreceptor activation is well established in rats, lambs, and rabbits, the cardiovascular responses to peripheral chemoreflex activation in conscious mice have not been delineated. Here we report that stimulation of peripheral chemoreceptors by potassium cyanide (KCN) in conscious mice elicits a unique biphasic response in blood pressure that is characterized by an initial and robust rise followed by a decrease in blood pressure, which is accompanied by a marked reduction in heart rate.
View Article and Find Full Text PDFChronic intermittent hypoxia (CIH) in rats produces changes in the central regulation of cardiovascular and respiratory systems by unknown mechanisms. We hypothesized that CIH (6% O(2) for 40 s, every 9 min, 8 h day(-1)) for 10 days alters the central respiratory modulation of sympathetic activity. After CIH, awake rats (n = 14) exhibited higher levels of mean arterial pressure than controls (101 +/- 3 versus 89 +/- 3 mmHg, n = 15, P < 0.
View Article and Find Full Text PDFDrug-induced scleroderma has been rarely reported, mostly with the features of diffuse scleroderma or acrosclerosis, and exceptionally with the characteristics of morphea. We report the case of an adult white woman, enrolled in a double-blind, placebo-controlled, multicentric trial evaluating the efficacy and safety of the cathepsin K inhibitor balicatib for osteoporosis. Typical morphea lesions developed on the patient's trunk 9 months after the beginning of therapy.
View Article and Find Full Text PDFE-cadherin cell-cell adhesion plays a major role in the maintenance of the morphology and function of epithelial tissues. Modulation of E-cadherin function is an important process in morphogenesis and tumour de-differentiation. We have previously shown that constitutively active Rac1 induces the disassembly of E-cadherin complexes from junctions in human keratinocytes.
View Article and Find Full Text PDFThe ability to monitor transcription factor (TF) activation in the central nervous system (CNS) has the potential to provide novel information regarding the molecular mechanisms underlying a wide range of neurobiological processes. However, traditional biochemical assays limit the mapping of TF activity to select time points. In vivo bioluminescence imaging (BLI) has emerged as an attractive technology for visualizing internal molecular events in the same animal over time.
View Article and Find Full Text PDF1. The aim of the present study was to evaluate the effects of peripheral chemoreceptor activation on myocardial contractility in an anaesthetic-free decerebrated rat preparation. 2.
View Article and Find Full Text PDFPeripheral chemoreflex activation with potassium cyanide (KCN) in awake rats or in the working heart-brainstem preparation (WHBP) produces: (a) a sympathoexcitatory/pressor response; (b) bradycardia; and (c) an increase in the frequency of breathing. Our main aim was to evaluate neurotransmitters involved in mediating the sympathoexcitatory component of the chemoreflex within the nucleus tractus solitarii (NTS). In previous studies in conscious rats, the reflex bradycardia, but not the pressor response, was reduced by antagonism of either ionotropic glutamate or purinergic P2 receptors within the NTS.
View Article and Find Full Text PDFSystemic ischaemia increases sympathetic activity via both reflex and direct effects on the nervous system, which include the hypothalamus and brainstem structures that provide excitatory drive to sympathetic pre-ganglionic motoneurones. Using an arterially perfused working heart-brainstem preparation (WHBP), we evaluated the sympathoexcitatory response recorded from the thoracic sympathetic chain (tSC) in response to systemic ischaemia (produced by arresting perfusion for 30 s) before and after transecting consecutively at both the ponto-medullary and medullary-spinal cord junctions. Ischaemia produced a striking increase in tSC activity that persisted after transecting at both the ponto-medullary and medullary-spinal cord levels (intact: 70+/-3%; ponto-medullary: 77+/-7%; medullary-spinal cord: 61+/-6%; n=9).
View Article and Find Full Text PDFAnorexia nervosa (AN) is a life-threatening eating disorder characterized by an inability to maintain a normal body weight and amenorrhoea, often associated with osteoporosis and increased risk of fragility fractures. Bone metabolism, including markers of bone turnover (serum total alkaline phosphatase, bone alkaline phosphatase [bone AP], osteocalcin [OC] and type I collagen C-telopeptide breakdown products [sCTX]) and bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) at the spine and at the hip, were evaluated in 55 consecutive women with AN undergoing a 3-month intensive nutritional rehabilitation program. The control group was constituted of 25 healthy young medical students.
View Article and Find Full Text PDFIn the present study, we tested the hypothesis that chronic intermittent hypoxia (CIH) produces changes in the autonomic and respiratory responses to acute peripheral chemoreflex activation. To attain this goal, 3-week-old rats were exposed to 10 days of CIH (6% O(2) for 40 s at 9 min intervals; 8 h day(-1)). They were then used to obtain a working heart-brainstem preparation and, using this unanaesthetized experimental preparation, the chemoreflex was activated with potassium cyanide (0.
View Article and Find Full Text PDFCenters of research all over the world are accomplishing studies about quality of life in several chronic conditions, for promoting interventions that promote improvement. This fact extends to spinal cord injury patients. This is a study with the aim of evaluating the quality of life of traumatic spinal cord injury people in the city of Fortaleza, Ceará, Brazil.
View Article and Find Full Text PDFRap1 has been implicated in the regulation of morphogenesis and cell-cell contacts in vivo (Asha et al., 1999; Hariharan et al., 1991; Knox and Brown, 2002) and in vitro (Hogan et al.
View Article and Find Full Text PDFChanges in heart rate (HR), thoracic sympathetic nerve activity (tSNA) and frequency of phrenic nerve discharge (PND) in response to microinjection of L-glutamate before and after local microinjection of ionotropic or metabotropic glutamate receptors antagonists into the commissural subnucleus of the NTS (comNTS) were investigated. The experiments were performed in an in situ unanesthetized decerebrated working heart-brainstem preparation (WHBP), and the main findings were as follows: (a) microinjection of increasing concentrations of L-glutamate (5, 25, 50, 250 and 500 mM) into the comNTS produced bradycardia, increase in tSNA and reduction in the frequency of the PND in a concentration-dependent manner; (b) both bradycardia and increase in tSNA were almost abolished by kynurenic acid (KYN, 250 mM, a nonselective ionotropic glutamate receptor antagonist); (c) the reduction in the frequency of the PND was reversed to an increase in the frequency of the PND after KYN and this increase was blocked by the sequential microinjection of MCPG (100 mM, a nonselective metabotropic glutamate receptor antagonist); and (d) microinjection of increasing concentrations of trans-ACPD (0.5, 1.
View Article and Find Full Text PDFCell-cell adhesion can occur in a calcium-dependent or calcium-independent manner, depending on the type of receptor involved. Establishment of cell contacts by either type of cell-cell adhesion (calcium-dependent or calcium-independent) has been shown to activate Rho GTPases in different cells. In this chapter, we describe the method used to assess the activation of Rho GTPases by cadherins, the prototype calcium-dependent adhesion receptor in epithelial cells.
View Article and Find Full Text PDFThe changes in thoracic sympathetic nerve activity, heart rate and frequency of phrenic nerve discharge in response to chemoreflex activation before and after bilateral microinjections of glutamate receptor antagonists into the comissural nucleus tractus solitarii (cNTS) were evaluated in the working heart-brainstem preparation of rats. Microinjections of kynurenic acid (KYN, 250 mM), (+/-)-alpha-methyl-4-carboxyphenylglycine (MCPG, 100 mM), or KYN plus MCPG into the cNTS were performed in three different groups. These microinjections into the cNTS did not affect the increase in the thoracic sympathetic nerve activity elicited by chemoreflex activation (KYN, 54 +/- 3 versus 51 +/- 2%, n = 11; MCPG, 48 +/- 5 versus 54 +/- 5%, n = 7; and KYN plus MCPG, 57 +/- 6 versus 55 +/- 3%, n = 5).
View Article and Find Full Text PDFIn epithelial cells, morphology is intrinsically related to function. Typically, polarization (i.e.
View Article and Find Full Text PDFThe ability of epithelial cells to polarize requires cell-cell adhesion mediated by cadherin receptors. During cell-cell contact, the mechanism via which a flat, spread cell shape is changed into a tall, cuboidal epithelial morphology is not known. We found that cadherin-dependent adhesion modulates actin dynamics by triggering changes in actin organization both locally at junctions and within the rest of the cell.
View Article and Find Full Text PDFRev Lat Am Enfermagem
February 2006
This is a theoretical reflection on the historical perception and conceptualization of madness and, consequently, on ways of acting towards it. We start from ancient Greek conceptions and move up to the present days, focusing mainly on those periods when perceptions and actions towards madness changed. We conclude that getting to know the historical forms of the madness concept is important to be able to denaturalize our conceptions and reflect about our current practice in care for patients going through mental suffering.
View Article and Find Full Text PDFLutzomyia cortelezzii was found in the urban area of Ilhéus, Bahia, Brazil. The appearance this phlebotomine in 100% of 288 hours of capture in Ilhéus' territory is an unpublished fact. The collection was by CDC light traps between December 2003 and May 2004, with a total of 81 collected samples.
View Article and Find Full Text PDFCurr Opin Cell Biol
October 2005
Small GTPases of the Ras superfamily play critical roles in epithelial biogenesis. Many key morphogenetic functions occur when small GTPases act at epithelial junctions, where they mediate an increasingly complex interplay between cell-cell adhesion molecules and fundamental cellular processes, such as cytoskeletal activity, polarity and trafficking. Important recent advances in this field include the role of additional members of the Ras superfamily in cell-cell contact stability and the capacity for polarity determinants to regulate small GTPase signalling.
View Article and Find Full Text PDFUnlabelled: Neridronate therapy in adult patients with OI significantly increases the cross-sectional area of the proximal radius. This observation may provide an additional explanation for the antifracture efficacy of bisphosphonates.
Introduction: Bisphosphonate therapy decreases by 70-90% the fracture risk in patients with osteogenesis imperfecta (OI).
1. Activation of peripheral chemoreceptors with KCN in the working heart-brainstem preparation from young male Wistar rats (70-90 g) increases phrenic (PNA; +105 +/- 18%) and thoracic (tSNA; +44 +/- 6%) sympathetic nerve activity compared with baseline and reduces heart rate (HR; from 377 +/- 27 to 83 +/- 6 b.p.
View Article and Find Full Text PDFUnlabelled: In a randomized controlled study, we investigated the effect of treatment with intravenous neridronate in prepubertal children with OI. Our study suggests that quarterly intravenous infusions of the bisphosphonate significantly raise the rate of increase in BMD at both the spine and hip, the projected area of the lumbar vertebrae, and height. These results are associated with a significant decrease in the risk of clinical fractures.
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