Experimental Characterization and Correlation of Mayer Waves in Retinal Vessel Diameter and Arterial Blood Pressure

A study was performed on seven traumatic neurologically complete quadriplegic (QP) males and seven age-matched healthy males (control) while they were at rest in the supine position in a climatic chamber (temperature 30 degrees C, relative humidity 60%). Arterial blood pressure waveforms were measured by a continuous noninvasive blood pressure-monitoring system based on arterial tonometry. Furthermore, the spontaneous beat-to-beat systolic blood pressure (SBP) variabilities of subjects were investigated by means of autoregressive power spectral analysis. As shown by earlier studies with an invasive (intra-arterial) blood pressure-monitoring system, in the control group there were two major spectral components: a high-frequency (HF) component [center frequency 0.27 +/- 0.02 (SE) Hz eq, power 0.9 +/- 0.2 mmHg2] and a low-frequency (LF) component (0.10 +/- 0.01 Hz eq, 5.2 +/- 1.4 mmHg2). On the contrary, in the QP group only the HF component was observed (0.28 +/- 0.03 Hz eq, 3.2 +/- 1.4 mmHg2). The results suggest that 1) in the QP subject the disappearance of the LF component in the SBP variability (i.e., the Mayer waves in humans) is presumably caused by the interruption of the spinal pathways linking supraspinal cardiovascular centers with the peripheral sympathetic outflow and 2) the cervical spinal sympathetic pathways may be instrumental in the genesis of the Mayer waves in humans.

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Age, Blood Pressure, and Retinal Vessel Diameter: Separate Effects and Interaction of Blood Pressure and Age

Investigative Opthalmology & Visual Science ◽

10.1167/iovs.06-0893 ◽

2007 ◽

Vol 48 (2) ◽

pp. 557 ◽

Cited By ~ 27

Author(s):

Shweta Kaushik ◽

Annette Kifley ◽

Paul Mitchell ◽

Jie Jin Wang

Keyword(s):

Blood Pressure ◽

Retinal Vessel ◽

Vessel Diameter ◽

Retinal Vessel Diameter

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Haemodynamic and Cerebrovascular Responses to Glycerol Infusion in Dogs

Clinical Science ◽

10.1042/cs0770535 ◽

1989 ◽

Vol 77 (5) ◽

pp. 535-539 ◽

Cited By ~ 2

Author(s):

Jiann-Liang Chen ◽

Yeou-Chih Wang ◽

Jia-Yi Wang

Keyword(s):

Blood Pressure ◽

Intracranial Pressure ◽

Cell Volume ◽

Arterial Blood Pressure ◽

Mean Arterial Blood Pressure ◽

Packed Cell Volume ◽

Vessel Diameter ◽

Serum Osmolarity ◽

Arterial Blood ◽

Pial Vessel

1. The response of cerebral blood vessels to hyperosmolar agents in vivo remains controversial, and little is known about the effect of glycerol on cerebral vessels. In this study we investigated the cerebrovascular response to intravenous administration of glycerol (1 g/kg, infused over 25 min) in dogs under pentobarbital anaesthesia. 2. Intracranial pressure, systemic arterial pressure, mean arterial blood pressure, serum osmolarity and packed cell volume were continuously monitored, and blood gases were checked frequently. Through a parietal cranial window, pial vessel diameter was measured by means of a surgical microscope and a video image-analyser. 3. Pial vessel diameter increased gradually with a maximum at 30 min after the beginning of glycerol infusion. The maximum increase in diameter in small (< 100 μm) vessels was 14.3%, whereas that in large (> 100 μm) vessels was 10.3%. There was only a slight increase (< 4%) in pial vessel diameter in vehicle-infused animals. The intracranial pressure decreased drastically after glycerol infusion, whereas the mean arterial blood pressure remained constant. There were correlations between the rise in serum osmolarity, fall in packed cell volume and vasodilatation, indicating that glycerol caused vasodilatation accompanied by plasma volume expansion. 4. Our data suggest that glycerol produces cerebral vasodilatation, which might be beneficial in cerebral ischaemia and vasospasm, in addition to its intracranial pressure-reducing effect on normal or oedematous brain. The degree of vasodilatation was not sufficient to affect the predominant intracranial pressure drop resulting from cerebral dehydration.

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Role of the ventral surface of medulla in the generation of Mayer waves

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1989.257.4.r804 ◽

1989 ◽

Vol 257 (4) ◽

pp. R804-R809 ◽

Cited By ~ 2

Author(s):

M. A. Haxhiu ◽

E. van Lunteren ◽

E. C. Deal ◽

N. S. Cherniack

Keyword(s):

Blood Pressure ◽

Arterial Blood Pressure ◽

Phrenic Nerve ◽

Pressure Oscillation ◽

Nerve Activity ◽

Intermediate Area ◽

Mayer Waves ◽

Phrenic Nerve Activity ◽

Arterial Blood ◽

Cyclic Changes

The regions adjacent to the ventrolateral medullary surface (VMS) play critical roles in the regulation of respiratory and cardiovascular function. Furthermore, these areas seem to be important sites for the integration of afferent inputs from certain sensory organs and the source of excitatory inputs to preganglionic sympathetic and parasympathetic neurons. To determine whether the VMS contributes to the generation of nonrespiratory-related periodic oscillations of arterial blood pressure (Mayer waves), excitatory substances, such as N-methyl-D-aspartate (NMDA), cholinergic agonists, and neuropeptides (substance P, neurokinin A, neurotensin), were applied topically to the intermediate area of VMS in anesthetized cats. In addition, the effects of application of lidocaine and inhibitory substances (benzodiazepines) on Mayer waves were studied. After application of excitatory substances to the VMS, we observed oscillations of arterial blood pressure, recurring with a period of 17.8 +/- 10 (SE) s, which had similar characteristics as the Mayer waves recorded during hypercapnia or hypoxia. In addition, cyclic changes in phrenic nerve activity and tracheal tone occurred with the same periodicity as arterial blood pressure oscillation. Application of lidocaine or benzodiazepines on the intermediate area of the VMS abolished Mayer waves observed during hypercapnia, hypoxia, or application of excitatory substances. These findings show for the first time that the VMS can be considered as one of several synaptic relays involved in the generation of arterial blood pressure oscillation, as well as the cyclic changes in phrenic nerve activity and tracheal smooth muscle tone that occur simultaneously.

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Air pollution and retinal vessel diameter and blood pressure in school-aged children in a region impacted by residential biomass burning

Scientific Reports ◽

10.1038/s41598-021-92269-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jill Korsiak ◽

Kay-Lynne Perepeluk ◽

Nicholas G. Peterson ◽

Ryan Kulka ◽

Scott Weichenthal

Keyword(s):

Blood Pressure ◽

Air Pollution ◽

Biomass Burning ◽

Retinal Vessel ◽

Vessel Diameter ◽

Pressure Measurements ◽

Mixed Effect ◽

Retinal Vessel Diameter ◽

Retinal Microvasculature ◽

Arteriolar Diameter

AbstractLittle is known about the early-life cardiovascular health impacts of fine particulate air pollution (PM2.5) and oxidant gases. A repeated-measures panel study was used to evaluate associations between outdoor PM2.5 and the combined oxidant capacity of O3 and NO2 (using a redox-weighted average, Ox) and retinal vessel diameter and blood pressure in children living in a region impacted by residential biomass burning. A median of 6 retinal vessel and blood pressure measurements were collected from 64 children (ages 4–12 years), for a total of 344 retinal measurements and 432 blood pressure measurements. Linear mixed-effect models were used to estimate associations between PM2.5 or Ox (same-day, 3-day, 7-day, and 21-day means) and retinal vessel diameter and blood pressure. Interactions between PM2.5 and Ox were also examined. Ox was inversely associated with retinal arteriolar diameter; the strongest association was observed for 7-day mean exposures, where each 10 ppb increase in Ox was associated with a 2.63 μm (95% CI − 4.63, − 0.63) decrease in arteriolar diameter. Moreover, Ox modified associations between PM2.5 and arteriolar diameter, with weak inverse associations observed between PM2.5 and arteriolar diameter only at higher concentrations of Ox. Our results suggest that outdoor air pollution impacts the retinal microvasculature of children and interactions between PM2.5 and Ox may play an important role in determining the magnitude and direction of these associations.

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