• The Korean Journal of Physiology
• /
• v.24 no.1
• /
• pp.51-65
• /
• 1990

The purpose of the present study was to examine the hemodynamic responses, especially in arterial and skin blood flows, in conjunction with the changes of plasma catecholamine levels as an indirect marker of adrenergic tone during the early stage of head-down tilt (HDT), and to evaluate the early physiological regulatory mechanism in simulated weightlessness. Ten mongrel dogs, weighing8\;{\sim}\;14\;kg, were intravenously anesthetized with nembutal, and postural changes were performed by using the tilting table. The postural changes were performed in the following order: supine, prone, HDT $(-6^{\circ}C)$ and lastly recovery prone position. The duration of each position was 30 minutes. The measurements were made before, during and after each postural change. The arterial blood flow $({\.{Q}})$ at the left common carotid and right brachial arteries was measured by the electromagnetic flowmeter. Blood pressure (BP) was directly measured by pressure transducer in the left brachial artery. To evaluate the peripheral blood flow, skin blood flow $({\.{Q}})$ was calculated by the percent changes of photoelectric pulse amplitude on the forepaw, and skin temperature was recorded. The peripheral vascular resistance (PR) was calculated by dividing respective mean BP values by ${\.{Q}}$ of both sides of common carotid and brachial arteries. Heart rate (HR), respiratory rate (f) and PH, $Po_{2},\;Pco_{2}$ and hematocrit of arterial and venous blood were also measured. The concentration of plasma epinephrine and norepinephrine was measured by radioenzymatic method. The results are summarized as follows: Tilting to head-down position from prone position, HR was initially increased (p<0.05) and BP was not significantly changed. While ${\.{Q}}$ of the common carotid artery was decreased (p<0.05) and PR through the head was increased, ${\.{Q}}$ of the brachial artery was increased (p<0.05) and PR through forelimbs was decreased. ${\.{Q}}$ of the forepaw was initially increased (p<0.05) and then slightly decreased, on the whole revealing an increasing trend. Plasma norepinephrine was slightly decreased and the epinephrine was slightly increased. f was increased and arterial pH was increased (p<0.05). In conclusion, the central blood pooling during HDT shows an increased HR via Bainbridge reflex and an increased ${\.{Q}}$ of the forepaw and brachial ${\.{Q}}$, due to decreased PR which may be originated from the depressor reflex of cardiopulmonary baroreceptors. It is suggested that the blood flow to the brain was adequately regulated throughout HDT $(-6^{\circ}C)$ in spite of central blood pooling. And it is apparent that the changes of plasma norepinephrine level are inversely proportional to those of ${\.{Q}}$ of the forepaw, and the changes of epinephrine level are paralleled with those of the brachial ${\.{Q}}$.

• International Journal of Fluid Machinery and Systems
• /
• v.1 no.1
• /
• pp.92-100
• /
• 2008

The main objective of this study was to clarify the origin of the unsteady flows arising in a mixed-flow vaneless diffuser system and also the effects of physical components of the system. The testing equipment consists of a straight tube, a swirl generator, and a mixed-flow vaneless diffuser. Pressure fluctuations of the flow through the tube and diffuser were measured by using a semiconductor-type pressure transducer and analyzed by an FFT analyzer. In the experiment, the velocity ratio (axial velocity/peripheral velocity) of the internal flow, and the geometric parameters of the diffuser were varied. Two kinds of unsteady flows were measured according to the combination of the components, and the origin of each unsteady flow was clarified. The fundamental frequencies of unsteady flows arose were examined by two-dimensional small perturbation analysis.

• Journal of Veterinary Clinics
• /
• v.21 no.3
• /
• pp.236-242
• /
• 2004

1,2-benzopyrone can stimulate macrophages to increase the ability of phagocytosis. Peripheral blood polymorphonuclear cells (PMN) and macrophages destroy microbial organisms with reactive oxygen species (ROS), called oxidative burst activity (OBA). This study was undertaken to determine whether 1,2-benzopyrone affects the OBA on the phagocytic response of canine peripheral blood phagocytes. The OBA of phagocytes in the addition or absence of latex beads was analyzed by flow cytometry system using dihydrorhodamine 123 (DHR). The direct treatments of 1,2-benzopyrone have no effect on the OBA of peripheral blood mononuclear cells (PBMC), PMN and monocyte-rich cells regardless of addition of latex beads. When latex beads are added to PMN, the OBA of PMN was remarkably enhanced by culture supernatant from PBMC but not PMN treated with 1,2-benzopyrone. Similary, it was also enhanced by human recombinant (hr) $TNF-\alpha.$ However, when latex beads were not added to PMN, its OBA was not enhanced by culture supernatant from either PBMC or PMN treated with 1,2-benzopyrone. The OBA of latex beads-phagocytized PBMC and monocyte-rich cells was not enhanced by culture supernatant from either PBMC or PMN treated with 1,2-benzopyrone. These results strongly suggested that 1,2-benzopyrone has an immunoenhancing effect on the OBA of PMN when phagocytic response occurred only. This enhanced OBA may be mediated through active humoral substance(s), such as $TNF-\alpha,$ produced by PBMC stimulated with 1,2-benzopyrone.

• The Korean Journal of Physiology and Pharmacology
• /
• v.22 no.4
• /
• pp.363-368
• /
• 2018

Hypotension is one of the potential causes of dizziness. In this review, we summarize the studies published in recent years about the electrophysiological and pharmacological mechanisms of hypotension-induced dizziness and the role of the vestibular system in the control of blood pressure in response to hypotension. It is postulated that ischemic excitation of the peripheral vestibular hair cells as a result of a reduction in blood flow to the inner ear following hypotension leads to excitation of the central vestibular nuclei, which in turn may produce dizziness after hypotension. In addition, excitation of the vestibular nuclei following hypotension elicits the vestibulosympathetic reflex, and the reflex then regulates blood pressure by a dualcontrol (neurogenic and humoral control) mechanism. In fact, recent studies have shown that peripheral vestibular receptors play a role in the control of blood pressure through neural reflex pathways. This review illustrates the dual-control mechanism of peripheral vestibular receptors in the regulation of blood pressure following hypotension.

• Journal of Veterinary Clinics
• /
• v.21 no.1
• /
• pp.23-28
• /
• 2004

1,2-benzopyrone has been shown to affect on the activation and stimulation of macrophage. To examine the immunostimulating effect of 1,2-benzopyrone on the phagocytic response of canine peripheral blood mononuclear cells (PBMC) as well as polymorphonuclear cells (PMN), the phagocytic activity of phagocytes was analyzed by flow cytometry system using FITC-labelled latex. The 1,2-benzopyrone did not show any direct effect on phagocytic response of PBMC and PMN. But it showed an enhanced effect on the phagocytic response of monocyte-rich cells fractioned by cell size from dot plot profile in flowcytometric cytography of PBMC. The phagocytic activity of these cells was also enhanced by addition of culture supernatant from PBMC treated with 1,2-benzopyrone. Similarly, the phagocytic activity of PMN but not PBMC in the same procedures was enhanced by culture supernatant from PBMC treated with 1,2-benzopyrone. However, the culture supernatant from PMN treated with 1.2-benzopyrone did not show the enhancing effect on phagocytic activity for monocyte-rich cells and PMN. These results, therefore, suggested that enhanced phagocytic activity of canine peripheral blood PMN and monocytes may be mainly mediated by humoral factor(S) released from PBMC treated with 1,2-benzopyrone.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.3
• /
• pp.237-242
• /
• 2013

This paper proposes a thermal peripheral blood flowmeter integrated with a force sensor that is capable of contact force compensation. We fabricate this blood flowmeter using a nickel RTD (resistance temperature detector) and piezoresistive force sensor by using microfabrication technology. In an experiment, we obtained a decreasing trend for the blood flow under an increasing contact force with a linear tendency of 31.7%/N. We then performed a compensation process based on this obtained trend. As a result, the maximum variance in the blood flow at 1-3N was 9.8%. Thus we achieved consistent blood flow measurement independent of the contact force. In this work, we verified that the thermal blood flowmeter integrated with a force sensor has the ability to accurately measure the blood flow independent of the contact force.

• Child Health Nursing Research
• /
• v.26 no.4
• /
• pp.434-444
• /
• 2020

Purpose: The aim of this retrospective study was to analyze the characteristics of peripheral arterial ischemia and tissue necrosis in premature babies, as well as the effects of nitroglycerin. Methods: In total, 513 newborns were enrolled who were admitted to the neonatal intensive care unit with a gestational age of 34 weeks or younger. Data were collected on general personal and clinical information, peripheral arterial ischemia, and nitroglycerin patch application in the premature infants. The collected data were analyzed using the χ² test, t-test, Mann-Whitney U test, logistic regression. Results: Thirty-six (7.0%) infants had peripheral arterial ischemia, while 477 (93.0%) infants did not. Lower gestational age (χ²=35.97, p<.001), lower birth weight (χ²=29.40, p<.001), lower blood pressure (χ²=23.10, p<.001), and insertion of an umbilical artery catheter (p<.001) were significantly associated with the occurrence of peripheral arterial ischemia. Among the preterm infants in whom nitroglycerin patches were applied, 30 (83.3%) premature infants without necrosis improved without complications, 4 (11.1%) showed hypotension, and 2 (5.6%) showed skin damage. Conclusion: Based on a review of our experiences with nitroglycerin patches, we recommend closely observing skin color and using nitroglycerin patches on the skin to help improve flow in premature infants with peripheral arterial ischemia.

• Biomedical Science Letters
• /
• v.29 no.1
• /
• pp.34-40
• /
• 2023

Smoking is one of the three major risk factors for vascular disease along with hypertension and hyperlipidemia. It is true that smoking has a negative effect on the circulatory system, and the frequency of coronary artery disease and peripheral vascular disease is significantly increased in smokers. Many epidemiological studies report that smokers have an approximately two-fold increased risk of coronary artery disease compared to non-smokers. This study was designed to investigate the relationship between cerebral blood flow change and depression index after acute smoking. Cerebral blood flow tests were performed before and after smoking in 8 subjects. Changes in blood flow after smoking were correlated with the depression score and negatively correlated with the depression score. In particular, there was a strong correlation with changes in blood flow in anterior cerebral artery. It is well known that changes in blood flow after smoking have a negative effect. In addition, considering the study that smoking aggravates the symptoms of depression, it was found that smoking and depression are factors that negatively affect each other.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.305-310
• /
• 1998

This research conducted concerning measures for the influence reduction to an investigation in the structure of offshore breakwater maintenance, an evaluation, a reexamination of the forecast, and a peripheral sediment transport environment. Furthermore, it aimed at the establishment of the beach transformation forecast method based on a hydraulic model study and a numeric simulation. A good result was obtained from a hydraulic model experiment and a numeric simulation as part of the basic research. And a qualitative evaluation of the flow field around the structure became possible since a numeric simulation examined flow field characteristics.

• Journal of Veterinary Clinics
• /
• v.23 no.4
• /
• pp.393-399
• /
• 2006

Ketamine, one of general anesthetics for human and veterinary use, is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist which interferes with the action of excitatory amino acids. It has been reported to impair various leukocyte functions. In this study, the effect of ketamine on the oxidative burst activity (OBA) of canine peripheral blood leukocytes was examined. The OBA of canine peripheral blood phagocytes was analyzed by flow cytometry system. Ketamine at higher concentration such as $1,000{\mu}M$ exhibited a low viability of leukocytes. Thus, ketamine was used at concentration of 10 to $500{\mu}M$ showing no cytotoxic effect and high cell viability. The OBA of leukocytes in the presence or absence of latex beads was analyzed by addition of dihydrorhodamine 123. The direct treatment of ketamine revealed the inhibitory effect on the OBA of peripheral blood polymorphonuclear cells (PMN) and monocyte-rich cells but not peripheral blood mononuclear cells (PBMC) in the presence of latex beads. However, when latex beads were not added to PMN, its OBA was not inhibited by ketamine. The OBA of PMN and monocyte-rich cells but not PBMC in the presence of latex beads was also inhibited by culture supernatant from ketamine-treated- PBMC but not -PMN. But the OBA of PMN in the absence of latex beads was not inhibited by culture supernatant from PBMC treated with ketamine. Therefore, these results suggested that ketamine has the inhibitory effect on the OBA of canine peripheral blood phagocytes such as neutrophils and monocytes during phagocytic response.