Impaired cerebral autoregulation may contribute to secondary injury in newborns with hypoxic-ischemic encephalopathy (HIE). Continuous, noninvasive assessment of cerebral pressure autoregulation can be achieved with bedside near-infrared spectroscopy (NIRS) and systemic mean arterial blood pressure (MAP) monitoring. This study aimed to evaluate whether impaired cerebral autoregulation measured ...

The aim of the study was to establish a parametric transfer function to describe the relationship between ocular perfusion pressure (OPP) and blood flow (BF) in the optic nerve head (ONH). A third-order parametric theoretical model was proposed to describe the ONH OPP-BF relationship within the lower OPP range of the autoregulation curve (< 80 mmHg) based on experimentally induced BF response t...

BACKGROUND AND PURPOSE The purpose of this study was to investigate the relationship between cerebrovascular autoregulation and outcome after aneurysmal subarachnoid hemorrhage. METHODS In a prospective observational study, 80 patients after severe subarachnoid hemorrhage were continuously monitored for cerebral perfusion pressure and partial pressure of brain tissue oxygen for an average of ...

Effects of Alpha Adrenergic Blockade on Autoregulation and Chemical Vasomotor Control of CBF in Stroke • Autoregulation and chemical vasomotor control of cerebral blood flow (CBF) were quantitatively tested in 19 patients with various types and sites of cerebral ischemia and infarction. The effect of alpha adrenergic blockade of cerebral vessels by phenoxybenzamine (PBZ) also was evaluated in m...

Abstract: Impaired Neurogenic Cerebrovascular Control and Dysautoregulation After Stroke • Cerebral autoregulation was tested in 32 patients with various anatomical locations and stages of ischemic cerebrovascular disease. Cerebral perfusion pressure (CPP) was raised or lowered in a standard manner by the use of head-up tilting (induced hypotension) and head-down tilting (induced hypertension)....

Autoregulation is the term used to describe the maintenance of constant perfusion over a range of arterial pressures. Autoregulation occurs in all vascular beds, but other mechanisms also act on vascular control, for example autonomic activity and plasma concentrations of hormones. The influence of these other mechanisms varies widely between different circuits, so that the effect of induced hy...

UNLABELLED In healthy individuals, cerebrovascular pressure autoregulation is preserved or even improved when propofol is infused. We examined the effect of an increase in propofol plasma concentration on pressure autoregulation in 10 head-injured patients. Using target-controlled infusions, the static rate of autoregulation was determined at a moderate (2.3 +/- 0.4 microg/mL) and a large (4.3 ...

The lactose operon of Escherichia coli is a paradigm system for quantitative understanding of gene regulation in prokaryotes. Yet, none of the many mathematical models built so far to study the dynamics of this system considered the fact that the Lac repressor regulates its own transcription by forming a transcriptional roadblock at the O3 operator site. Here we study the effect of autoregulati...

Our previous data indicated that various subtypes of connexin (Cx) were expressed in the juxtaglomerular apparatus. Experiments were performed to characterize the effects on renal autoregulation of specific mimetic peptides that inhibit these Cx subtypes in Wistar-Kyoto rats. Intrarenal infusion of (Cx37,43)GAP27 increased autoregulatory index of renal plasma flow (0.06 +/- 0.05 to 0.47 +/- 0.0...

Cerebral autoregulation (CA) is an most important mechanism responsible for the relatively constant blood flow supply to brain when cerebral perfusion pressure varies. Its assessment in nonacute cases has been relied on the quantification of the relationship between noninvasive beat-to-beat blood pressure (BP) and blood flow velocity (BFV). To overcome the nonstationary nature of physiological ...