Photosynthesis and other factors affecting the establishment and maintenance of cnidarian-dinoflagellate symbiosis.

Coral growth depends on the partnership between the animal hosts and their intracellular, photosynthetic dinoflagellate symbionts. In this study, we used the sea anemone , a laboratory model for coral biology, to investigate the poorly understood mechanisms that mediate symbiosis establishment and maintenance. We found that initial colonization of both adult polyps and larvae by a compatible algal strain was more effective when the algae were able to photosynthesize and that the long-term maintenance of the symbiosis also depended on photosynthesis.

Molecular insights into the Darwin paradox of coral reefs from the sea anemone Aiptasia.

Symbiotic cnidarians such as corals and anemones form highly productive and biodiverse coral reef ecosystems in nutrient-poor ocean environments, a phenomenon known as Darwin's paradox. Resolving this paradox requires elucidating the molecular bases of efficient nutrient distribution and recycling in the cnidarian-dinoflagellate symbiosis. Using the sea anemone Aiptasia, we show that during symbiosis, the increased availability of glucose and the presence of the algae jointly induce the coordinated up-regulation and relocalization of glucose and ammonium transporters.

Automated analysis of finger blood pressure recordings provides insight in determinants of baroreflex sensitivity and heart rate variability-the HELIUS study.

Sympathovagal balance is important in the pathogenesis of hypertension and independently associated with mortality. We evaluated the value of automated analysis of cross-correlation baroreflex sensitivity (xBRS) and heart rate variability (HRV) and its relationship with clinical covariates in 13,326 participants from the multi-ethnic HELIUS study. Finger blood pressure (BP) was continuously recorded, from which xBRS, standard deviation of normal-to-normal intervals (SDNN), and squared root of mean squared successive difference between normal-to-normal intervals (RMSDD) were determined.

Long-term maintenance of a heterologous symbiont association in Acropora palmata on natural reefs.

The sensitivity of reef-building coral to elevated temperature is a function of their symbiosis with dinoflagellate algae in the family Symbiodiniaceae. Changes in the composition of the endosymbiont community in response to thermal stress can increase coral thermal tolerance. Consequently, this mechanism is being investigated as a human-assisted intervention for rapid acclimation of coral in the face of climate change.

Evidence for adaptive morphological plasticity in the Caribbean coral, .

Genotype-by-environment interactions (GxE) indicate that variation in organismal traits cannot be explained by fixed effects of genetics or site-specific plastic responses alone. For tropical coral reefs experiencing dramatic environmental change, identifying the contributions of genotype, environment, and GxE on coral performance will be vital for both predicting persistence and developing restoration strategies. We quantified the impacts of G, E, and GxE on the morphology and survival of the endangered coral, , through an in situ transplant experiment exposing common garden (nursery)-raised clones of ten genotypes to nine reef sites in the Florida Keys.

Insights into coral bleaching under heat stress from analysis of gene expression in a sea anemone model system.

Loss of endosymbiotic algae ("bleaching") under heat stress has become a major problem for reef-building corals worldwide. To identify genes that might be involved in triggering or executing bleaching, or in protecting corals from it, we used RNAseq to analyze gene-expression changes during heat stress in a coral relative, the sea anemone Aiptasia. We identified >500 genes that showed rapid and extensive up-regulation upon temperature increase.

Angiotensin II-induced hypertension in rats is only transiently accompanied by lower renal oxygenation.

Activation of the renin-angiotensin system may initiate chronic kidney disease. We hypothesised that renal hypoxia is a consequence of hemodynamic changes induced by angiotensin II and occurs prior to development of severe renal damage. Male Sprague-Dawley rats were infused continuously with angiotensin II (350 ng/kg/min) for 8 days.

Sympathetic activation by lower body negative pressure decreases kidney perfusion without inducing hypoxia in healthy humans.

Purpose: There is ample evidence that systemic sympathetic neural activity contributes to the progression of chronic kidney disease, possibly by limiting renal blood flow and thereby inducing renal hypoxia. Up to now there have been no direct observations of this mechanism in humans. We studied the effects of systemic sympathetic activation elicited by a lower body negative pressure (LBNP) on renal blood flow (RBF) and renal oxygenation in healthy humans.

Nitric Oxide Synthase Inhibition Induces Renal Medullary Hypoxia in Conscious Rats.

Background Renal hypoxia, implicated as crucial factor in onset and progression of chronic kidney disease, may be attributed to reduced nitric oxide because nitric oxide dilates vasculature and inhibits mitochondrial oxygen consumption. We hypothesized that chronic nitric oxide synthase inhibition would induce renal hypoxia. Methods and Results Oxygen-sensitive electrodes, attached to telemeters, were implanted in either renal cortex (n=6) or medulla (n=7) in rats.

Renal blood oxygenation level-dependent magnetic resonance imaging to measure renal tissue oxygenation: a statement paper and systematic review.

Tissue hypoxia plays a key role in the development and progression of many kidney diseases. Blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is the most promising imaging technique to monitor renal tissue oxygenation in humans. BOLD-MRI measures renal tissue deoxyhaemoglobin levels voxel by voxel.

Renal sympathetic nerve activity after catheter-based renal denervation.

Background: Catheter-based renal sympathetic denervation (RDN) has been considered a potential treatment for therapy resistant hypertension (RHT). However, in a randomized placebo-controlled trial, RDN did not lead to a substantial blood pressure (BP) reduction. We hypothesized that variation in the reported RDN efficacy might be explained by incomplete nerve disruption as assessed by renal I-meta-iodobenzylguanidine (I-mIBG) scintigraphy.

Glucose-Induced Trophic Shift in an Endosymbiont Dinoflagellate with Physiological and Molecular Consequences.

Interactions between the dinoflagellate endosymbiont and its cnidarian hosts (e.g. corals, sea anemones) are the foundation of coral-reef ecosystems.

Metabolic acidosis caused by concomitant use of paracetamol (acetaminophen) and flucloxacillin? A case report and a retrospective study.

Purpose: A patient was identified with severe metabolic acidosis, a high anion gap and 5-oxoproline accumulation, probably caused by the simultaneous use of paracetamol (acetaminophen) and flucloxacillin. We wanted to investigate the necessity to control the interaction between both drugs with an automatic alert system.

Methods: To investigate the relevance of the interaction of paracetamol and flucloxacillin, a retrospective study was conducted.

A tri-exponential model for intravoxel incoherent motion analysis of the human kidney: In silico and during pharmacological renal perfusion modulation.

In the kidneys, there is both blood flow through the capillaries and flow of pre-urine through the tubuli and collecting ducts. We hypothesized that diffusion-weighted (DW) MRI measures both blood and pre-urine flow when using a tri-exponential intravoxel incoherent motion (IVIM) model. Our aim was to systematically investigate and optimize tri-exponential IVIM-analysis for the kidney and test its sensitivity to renal perfusion changes in humans.

Circadian Rhythm in Kidney Tissue Oxygenation in the Rat.

Blood pressure, renal hemodynamics, electrolyte, and water excretion all display diurnal oscillation. Disturbance of these patterns is associated with hypertension and chronic kidney disease. Kidney oxygenation is dependent on oxygen delivery and consumption that in turn are determined by renal hemodynamics and metabolism.

Blood Pressure Increase during Oxygen Supplementation in Chronic Kidney Disease Patients Is Mediated by Vasoconstriction Independent of Baroreflex Function.

Renal hypoxia is thought to be an important pathophysiological factor in the progression of chronic kidney disease (CKD) and the associated hypertension. In a previous study among CKD patients, supplementation with 100% oxygen reduced sympathetic nerve activity (SNA) and lowered blood pressure (BP). We aimed to assess the underlying haemodynamic modulation and hypothesized a decreased systemic vascular resistance (SVR).

Epidemiology and management of hypertension in paediatric and young adult kidney transplant recipients in The Netherlands.

Introduction: Hypertension in kidney transplant recipients (KTRs) is a risk factor for cardiovascular mortality and graft loss. Data on the prevalence of hypertension and uncontrolled hypertension (uHT) in paediatric and young adult KTRs are scarce. Also, it is unknown whether 'transition' (the transfer from paediatric to adult care) influences control of hypertension.

Exogenous and endogenous angiotensin-II decrease renal cortical oxygen tension in conscious rats by limiting renal blood flow.

Key Points: Our understanding of the mechanisms underlying the role of hypoxia in the initiation and progression of renal disease remains rudimentary. We have developed a method that allows wireless measurement of renal tissue oxygen tension in unrestrained rats. This method provides stable and continuous measurements of cortical tissue oxygen tension (PO2) for more than 2 weeks and can reproducibly detect acute changes in cortical oxygenation.

Blood pressure reduction after gastric bypass surgery is explained by a decrease in cardiac output.

Unlabelled: Blood pressure (BP) decreases in the first weeks after Roux-and-Y gastric bypass surgery. Yet the pathophysiology of the BP-lowering effects observed after gastric bypass surgery is incompletely understood. We evaluated BP, systemic hemodynamics, and baroreflex sensitivity in 15 obese women[mean age 42 ± 7 standard deviation (SD) yr, body mass index 45 ± 6 kg/m] 2 wk before and 6 wk following Roux-and-Y gastric bypass surgery.

Initial orthostatic hypotension in teenagers and young adults.

Objective: To assess: (1) the frequency of an abnormally large fall in blood pressure (BP) upon standing from supine in patients with initial orthostatic hypotension (IOH); (2) the underlying hemodynamic mechanisms of this fall in BP upon standing from supine and from squatting.

Methods: In a retrospective study of 371 patients (≤30 years) visiting the syncope unit, the hemodynamic response to standing and squatting were studied in 26 patients who were diagnosed clinically with IOH, based on history taking only. In six patients changes in cardiac output (CO) and systemic vascular resistance (SVR) were determined, and the underlying hemodynamics were analyzed.

Orthostatic Hypotension in Parkinson's Disease: The Relation of Blood Pressure Tests and Symptoms in Daily Life.

Background: Orthostatic hypotension (OH) is common in Parkinson's disease (PD), but the relation between the results of orthostatic blood pressure tests and orthostatic symptoms in daily life is not clear.

Methods: We performed a cross-sectional study in an incident nontertiary care cohort of PD patients with additional recruitment of PD patients from our own outpatient clinic. We recruited sex- and age-matched controls.

A modified device for continuous non-invasive blood pressure measurements in humans under hyperbaric and/or oxygen-enriched conditions.

Background: It would be desirable to safely and continuously measure blood pressure noninvasively under hyperbaric and/or hyperoxic conditions, in order to explore haemodynamic responses in humans under these conditions.

Methods: A systematic analysis according to 'failure mode and effects analysis' principles of a commercially available beat-by-beat non-invasive blood pressure monitoring device was performed using specifications provided by the manufacturer. Possible failure modes related to pressure resistance and fire hazard in hyperbaric and oxygen-enriched environments were identified and the device modified accordingly to mitigate these risks.

Magnetic Resonance Imaging-Derived Renal Oxygenation and Perfusion During Continuous, Steady-State Angiotensin-II Infusion in Healthy Humans.

Background: The role of kidney hypoxia is considered pivotal in the progression of chronic kidney disease. A widely used method to assess kidney oxygenation is blood oxygen level dependent (BOLD)-magnetic resonance imaging (MRI), but its interpretation remains problematic. The BOLD-MRI signal is the result of kidney oxygen consumption (a proxy of glomerular filtration) and supply (ie, glomerular perfusion).