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Perfusion pressure

François Seghers, Xavier Yerna, Nadège Zanou, Olivier Devuyst, Rudi Vennekens, Bernd Nilius, Philippe Gailly
The renin - angiotensin system is a crucial blood pressure regulation system. It consists of a hormonal cascade where the rate-limiting enzyme is renin, which is secreted in blood flow by renal juxtaglomerular (JG) cells in response to low pressure in the renal afferent arteriole. In contrast, an increase in blood pressure results in a decreased renin secretion. This is accompanied by a transitory increase in [Ca(2+) ]i of JG cells. The inverse relationship between [Ca(2+) ]i and renin secretion has been called the "calcium paradox" of renin release...
October 25, 2016: Journal of Physiology
Jean-Louis Vincent, Marc Leone
Distributive shock is associated with decreased systemic vascular resistance and altered oxygen extraction. Septic shock is the most frequent form of distributive shock. In shock states, duration of hypotension is associated with poor outcomes. The speed at which treatment to restore adequate perfusion pressure is initiated is, therefore, important to improve survival. Areas covered: This review presents an overview of the literature related to the management of vasopressor-dependent distributive shock, and in particular the relationship between arterial pressure and organ perfusion and function...
October 24, 2016: Expert Review of Anti-infective Therapy
Christos Lazaridis
Shock is a systemic form of acute circulatory failure leading to cellular dysoxia and death. Such a state of aerobic metabolism failure also underlies neuronal cell death in severe traumatic brain injury. It is becoming increasingly recognized that ischemic hypoxia is not the sole mechanism and that multiple alternate cooperating mechanisms may be responsible for compromising neuronal oxidative metabolism. These different mechanisms can be usefully understood via analysis of the classic subdivisions of tissue hypoxia...
October 11, 2016: Journal of Critical Care
P X Kuan, P W Tan, A T Jobli, A R Norsila
INTRODUCTION: Differences in systolic blood pressure reading between arms are common but could signal trouble if the discrepancy is significant. Early detection of aortic dissection could invariably determine patient's survivability. Hence, a high index of suspicion with prompt diagnostic imaging is vital for accurate diagnosis. CASE PRESENTATION: A previously healthy 35-year-old lady was referred from district hospital for hypertensive cardiomyopathy complicated by acute pulmonary oedema...
August 2016: Medical Journal of Malaysia
Yasushi Wada, Tomomi Higashide, Atsushi Nagata, Kazuhisa Sugiyama
Purpose: To investigate longitudinal changes in mean blur rate (MBR) measured by laser speckle flowgraphy (LSFG) in the rat optic nerve head (ONH), and the reproducibility of MBR. Methods: Rats were dilated under general anesthesia. Intraocular pressure (IOP), blood pressure, ocular perfusion pressure (OPP), heart rate, and LSFG were measured 30 minutes later. Mean blur rate in the ONH was determined using LSFG-Micro and was subdivided into MBR of the total area (MA), vessel region (MV), and tissue region (MT)...
October 1, 2016: Investigative Ophthalmology & Visual Science
Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
Ryuya Hashimoto, Tetsuya Sugiyama, Makoto Ubuka, Takatoshi Maeno
PURPOSE: To investigate optic nerve head (ONH) blood flow changes resulting from intraocular pressure (IOP) elevation in subjects without systemic disorders. MATERIALS AND METHODS: Eighteen eyes of 18 patients who underwent vitrectomy to treat an epiretinal membrane or macular hole at Toho University Sakura Medical Center were included. Following standard 25-gauge microincision vitreous surgery, mean blur rate (MBR) in tissue (MT), an index of ONH blood flow, was measured using laser speckle flowgraphy...
October 21, 2016: Current Eye Research
Colleen E Dugan, James P Grinias, Sebastian D Parlee, Mahmoud El-Azzouny, Charles R Evans, Robert T Kennedy
Microfluidics is an enabling technology for both cell biology and chemical analysis. We combine these attributes with a microfluidic device for on-line solid-phase extraction (SPE) and mass spectrometry (MS) analysis of secreted metabolites from living cells in culture on the chip. The device was constructed with polydimethylsiloxane (PDMS) and contains a reversibly sealed chamber for perfusing cells. A multilayer design allowed a series of valves to control an on-chip 7.5 μL injection loop downstream of the cell chamber with operation similar to a six-port valve...
October 19, 2016: Analytical and Bioanalytical Chemistry
M C Burg, P Lunkenheimer, P Niederer, C Brune, K Redmann, M Smerup, U Spiegel, F Becker, D Maintz, W Heindel, R H Anderson
Purpose: There are ongoing arguments as to how cardiomyocytes are aggregated together within the ventricular walls. We used pneumatic distension through the coronary arteries to exaggerate the gaps between the aggregated cardiomyocytes, analyzing the pattern revealed using computed tomography, and validating our findings by histology. Methods: We distended 10 porcine hearts, arresting 4 in diastole by infusion of cardioplegic solutions, and 4 in systole by injection of barium chloride. Mural architecture was revealed by computed tomography, measuring also the angulations of the long chains of cardiomyocytes...
November 2016: RöFo: Fortschritte Auf Dem Gebiete der Röntgenstrahlen und der Nuklearmedizin
Triantafyllos Stylianopoulos
Tumor progression and response to treatment is determined in large part by the generation of mechanical stresses that stem from both the solid and the fluid phase of the tumor. Furthermore, elevated solid stress levels can regulate fluid stresses by compressing intratumoral blood and lymphatic vessels. Blood vessel compression reduces tumor perfusion, while compression of lymphatic vessels hinders the ability of the tumor to drain excessive fluid from its interstitial space contributing to the uniform elevation of the interstitial fluid pressure...
October 19, 2016: Journal of Biomechanical Engineering
Xinlei Song, Shu Zhang, Yanna Cheng, Ting Zhao, Qianqian Lian, Lu Lu, Fengshan Wang
OBJECTIVES: To evaluate the resuscitative efficacy and the effect on reperfusion injury of two site-specific PEGylated human serum albumins modified with linear or branched PEG20kDa, compared with saline, 8% human serum albumin and 25% human serum albumin, in a hemorrhagic shock model. SETTING: Laboratory. SUBJECTS: Male Wistar rats. DESIGN: Prospective study. INTERVENTIONS: Rats were bled to hemorrhagic hypovolemic shock and resuscitated with different resuscitation fluids...
November 2016: Critical Care Medicine
William J Readdy, Rajiv Saigal, William D Whetstone, Anthony N Mefford, Adam R Ferguson, Jason F Talbott, Tomoo Inoue, Jacqueline C Bresnahan, Michael S Beattie, Jonathan Pan, Geoffrey T Manley, Sanjay S Dhall
BACKGROUND: Increased spinal cord perfusion and blood pressure goals have been recommended for spinal cord injury (SCI). Penetrating SCI is associated with poor prognosis, but there is a paucity of literature examining the role of vasopressor administration for the maintenance of mean arterial pressure (MAP) goals in this patient population. OBJECTIVE: To elucidate this topic and to determine the efficacy of vasopressor administration in penetrating SCI by examining a case series of consecutive penetrating SCIs...
November 2016: Neurosurgery
Shadi Shafaghi, Azizollah Abbasi Dezfuli, Zahra Ansari Aval, Kambiz Sheikhy, Behrooz Farzanegan, Esmaeil Mortaz, Habib Emami, Clemens Aigner, Fatemeh Sadat Hosseini-Baharanchi, Katayoun Najafizadeh
OBJECTIVES: Although the number of lung transplants is limited because of general shortage of organ donors, ex vivo lung perfusion is a novel method with 2 main benefits, including better evaluation of lung potential and recovery of injured lungs. The main aim of this study was to establish and operationalize ex vivo lung perfusion as the first experience in Iran. MATERIALS AND METHODS: This was a prospective operational research study on 5 cases, including 1 pig from Vienna Medical University and 4 patients from Masih Daneshvari Hospital...
October 14, 2016: Experimental and Clinical Transplantation
Nophanan Chaikittisilpa, Abhijit V Lele, Vivian H Lyons, Bala G Nair, Shu-Fang Newman, Patricia A Blissitt, Monica S Vavilala
BACKGROUND: Current guidelines recommend routine clamping of external ventricular drains (EVD) for intrahospital transport (IHT). The aim of this project was to describe intracranial hemodynamic complications associated with routine EVD clamping for IHT in neurocritically ill cerebrovascular patients. METHODS: We conducted a retrospective review of cerebrovascular adult patients with indwelling EVD admitted to the neurocritical care unit (NICU) during the months of September to December 2015 at a tertiary care center...
October 18, 2016: Neurocritical Care
S J van Rooijen, D Huisman, M Stuijvenberg, J Stens, R M H Roumen, F Daams, G D Slooter
BACKGROUND: Colorectal anastomotic leakage (CAL) is a major surgical complication in intestinal surgery. Despite many optimizations in patient care, the incidence of CAL is stable (3-19%) [1]. Previous research mainly focused on determining patient and surgery related risk factors. Intraoperative non-surgery related risk factors for anastomotic healing also contribute to surgical outcome. This review offers an overview of potential modifiable risk factors that may play a role during the operation...
October 15, 2016: International Journal of Surgery
Clive Rosendorff
Many guidelines for the management of hypertension have recommended that the goal of antihypertensive treatment in the elderly (usually specified as 80 years or above) should be less than 150/90 mmHg. SPRINT included subjects 50 years or above, and a substantial proportion of subjects 75 years and older. These are individuals at high risk for adverse cardiovascular events because of high prevalence of hypertension and atherosclerotic disease. The less stringent BP goals have been based on a percieved danger of lowering BP to levels that threaten vital organ pefusion (myocardium, brain, kidney)...
September 2016: Journal of Hypertension
Tomofumi Fushima, Akiyo Sekimoto, Takahiro Minato, Takuya Ito, Yuji Oe, Kiyomi Kisu, Emiko Sato, Kenichi Funamoto, Yoshitaka Kimura, Sadayoshi Ito, Hiroshi Sato, Nobuyuki Takahashi
OBJECTIVE: Preeclampsia (PE) is a pregnancy-induced hypertension with proteinuria that typically develops after 20 weeks of gestation. A reduction in uterine blood flow causes placental ischemia and placental release of anti-angiogenic factors such as soluble fms-like tyrosine kinase (sFlt-1) followed by PE. Although the reduced uterine perfusion pressure (RUPP) model is widely used in rats, investigating the genetics of PE has been problematic because it has been difficult to make a useful RUPP model in mice...
September 2016: Journal of Hypertension
Christopher Wilcox
OBJECTIVE: CKD progression is accelerated by hypertension and impaired myogenic responses (MRs) of renal afferent arterioles leading to renal barotrauma. We tested the hypothesis that reactive oxygen species (ROS) underlie both these processes and that ROS metabolism by tempol would thereby protect kidneys. DESIGN AND METHODS: Rat and mouse 5/6 nephrectomy models of reduced renal mass (RRM) vs sham were fed high salt for 3 months during BP telemetry. Individual afferent arterioles were isolated and perfused...
September 2016: Journal of Hypertension
Kazuyuki Shimada
Stroke is known to frequently recur in patients with a history of cerebrovascular disease, and the control of hypertension is extremely important for the treatment of those patients. The robust relationship between the recurrent cerebrovascular disease and blood pressure control has been demonstrated in large-scale clinical studies. The antihypertensive drug therapy significantly reduces the recurrence rate of all types of cerebrovascular disease, incidences of myocardial infarction and all vascular events...
September 2016: Journal of Hypertension
Sang-Chol Lee
Chronic hypertension can result in deleterious effects on various vascular organs including the heart and vessels. Cardiovascular magnetic resonance (CMR) has the unique advantage of the ability to assess ventricular volumes and function, valvular abnormalities, vascular pathology, myocardial perfusion and tissue characterization with high accuracy and reproducibility and also avoid the risk of radiation. As this is the case, CMR seems to be an ideal method for comprehensive assessment of patients with systemic hypertension...
September 2016: Journal of Hypertension
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