• Childhood Kidney Diseases
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• v.19 no.2
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• pp.71-78
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• 2015

The incidence of acute kidney injury (AKI) in critically ill pediatric patients has been reported as increasing to 25 %, depending on population characteristics. The etiology of AKI has changed over the last 10-20 years from primary renal disease to the renal conditions associated with systemic illness. The AKI in pediatric population is associated with increased mortality and morbidity, and prevention is needed to reduce the consequence of AKI. It is known that the most important risk factors for AKI in critically ill pediatric patients are clinical conditions to be associated with decreased renal blood flow, direct renal injury, and illness severity. Renal hypoperfusion leads to neurohormonal activation including renin-angiotensin-aldosterone system, sympathetic nervous system, antidiuretic hormone, and prostaglandins. Prolonged renal hypoperfusion can result in acute tubular necrosis. The direct renal injury can be predisposed under the condition of renal hypoperfusion, and appropriate treatment of volume depletion is important to prevent AKI. The preventable causes of AKI include contrast-induced nephropathy, hemodynamic instability, inappropriate mediation use, and multiple nephrotoxic insults. Given the evidence of preventable factors for AKI, several actions such as the use of protocol for prevention of contrast-induced nephropathy, appropriate treatment of volume depletion, vigorous treatment of sepsis, avoidance of combinations of nephrotoxic medications, and monitoring of levels of drugs should be recommended.

• Journal of Oriental Neuropsychiatry
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• v.18 no.3
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• pp.113-122
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• 2007

The purpose of this study was to evaluate the effects of mental stress measured with heart rate variability(HRV) in healthy adults and to evaluate the effects of laserneedle acupuncture therapy in healthy adults. Methods : 25 healthy volunteers participated in this study. The volunteers were divided randomly, the real laserneedle acupuncture therapy group or the sham laserneedle acupuncture therapy group. First, After 5 minute rest, mental stress was given with stroop color word task and calculation task. And then laserneedle acupuncture therapy or sham laserneedle therapy was done on HT8(少府) for 15 minute. HRV was recorded in 3 period-before stress, after stress, and after laserneedle or sham acupuncture therapy. Results : LF was significantly increased after mental stress. And there was no significant difference between the real laserneedle acupuncture therapy group and the sham laserneedle acupuncture therapy group. Conclusions : This results show that mental stress-stroop color word test and calculation test for 10 minute- contribute to activation of the sympathetic nervous system.

• The Korean Journal of Physiology
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• v.10 no.1
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• pp.49-54
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• 1976

The change of heart rates during Flack Test was observed in the pregnant women, $24{\sim}48$weeks, of gestational age, to analyze mechanical and neural regulatory factors in responses to the positive lung inflation. The results obtained were summarized as followings: 1) Endurance tine of Flack Test was 37.6 sec, in the nonpregnant women, and 25.1 sec. in the pregnant women. 2) When Flack Test was employed, heart rate was decreased in early stage of Flack Test in the pregnant women, while heart rate was increased in the nonpregnant women. 3) In the pregnant women bradycardia due to abdominal mechanical intervention in early stage of Flack Test was prominent, while tachycardia was found in the nonpregnant women. 4) During Flack Test, tachycardia due to sympathetic central reflex activation was observed immediately after bradycardia in early stage of Flack Test. 5) It may be noted that Flack Test employed in the present study is a useful model to evaluate and analyze the neural and mechanical abdominal intervention factor in response to the positive inflation of lung in pregnant women.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.2
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• pp.11-18
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• 2002

Psychological and physiological effects of the simulator sickness could be important bias factors for the sensibility evaluation. The purpose of the present study was to clear the differences of psychophysiological responses due to individual sensitivity of simulator sickness. The present experiment tried to investigate the simulator sickness objectively by observing the change of the simulator sickness for the different level of sickness groups (sick and non_sick group). The subjective evaluations using Simulator Sickness Questionnaire (SSQ) and physiological responses were measured every five minutes when they were driving as 60km/h in the driving graphic simulator. Response level of the subjective evaluation for all subjects on the simulator sickness was linearly increased with time for every item, and the response level of sick group was bigger than that of non_sick group. When the analysis on central nervous system was done separately on the sick and the non_sick group, there was significant difference in the parameter $\theta$/total at Fz and Cz. Although the analysis on autonomic nervous system for all subjects showed the increased activation of sympathetic nervous system, there was no significant difference between the sick and non_sick group. In summary, it is necessary to select the subjects who feel less simulator sickness in order to be accurate sensibility evaluation. The parameters to distinguish between the sick and non_sick group were the change on $\theta$/total and subjective evaluation using SSQ.

• Science of Emotion and Sensibility
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• v.2 no.2
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• pp.37-42
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• 1999

Long-term exposure to loud noise affects performance since it changes arousal level, distracts attention, and also is able to evoke subjective stress accompanied by negative emotional states. The purpose of the study was to analyze dynamics of subjective and physiological variables during a relatively long-lasting (30 min) exposure to white noise (85 dB[A]). Physiological signals were recorded on 15 college students during 30 min of intense auditory stimulation. Autonomic variables, namely skin conductance level , non-specific SCR number, inter-best intervals in ECG, heart rate variability index (HF/LF ratio of HRV), skin temperature, as well as respiration rate were analyzed on 5 min epoch basis. Psychological assessment (subjective rating of stress level) was also repeated every 5 min. Statistical analysis was employed to trace the time course of the dynamics of subjective and autonomic physiological variables and their relationships. Results showed that the intense noise evoked subjective stress as well as associated autonomic nervous system responses. However it was shown that physiological variables endured specific changes in the process of exposure to the loud white noise. Discussed were probable psychophysiological mechanisms mediating reactivity to long-term auditory stimulation of high intensity, namely short-term activation, followed by transient adaptation (with relatively stable autonomic balance) and then a subsequent wave of arousal due to tonic sympathetic dominance.

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.101-111
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• 1990

The effect of physostigmine (PS), which has been shown to act on the muscarinic receptors in the brains of the rat, dog and cat, on the arterial blood pressure (BP) was investigated in urethane-anesthetized rabbits. Intravenous (iv) PS, $25{\sim}300\;{\mu}g/kg$, caused little change in BP. However, after treatment of rabbits with either of chlorisondamine (CS), hexamethonium, intracerebroventricular (icv) clonidine, icv xylazine and icy reserpine iv PS produced a pressor response. Spinalization of the rabbit also caused iv PS to increase BP. The pressor effect of iv PS in CS-treated rabbits was markedly reduced after prazosin or pirenzepine. Iv PS inhibited the pressor response to McN-A-343 in CS-treated and in spinal rabbits; alternately during the infusion of McN-A-343 iv PS failed to produce the pressor response. The pressor response to DMPP was not affected by iv PS. Icv PS, $12{\sim}200\;{\mu}g/kg$, produced a pressor response which was accentuated after CS-treatment. This pressor effect was inhibited, though not complete, by prazosin or by pirenzepine. A simultaneous treatment of rabbits with both $[Sar^{1},\;Ala^{8}]-angiotensin$ II, an angiotensin II antagonist, and prazosin or pirenzepine almost completely abolished the pressor effect of icv PS, whereas the angiotensin II antagonist did not enhance the inhibitory effect of pirenzepine and prazosin on the pressor response to iv PS . Icv pirenzepine blocked the pressor response to icv PS without affecting that to iv PS. The present results show that the pressor response to iv PS in CS-treated and in spinal rabbits arises from stimulation of the muscarinic receptors in the sympathetic ganglia, whereas the pressor response by icv PS via activation of the muscarinic receptors in the brain which causes an enhancement in the outflow of sympathetic discharge and angiotensin. The results also suggest that iv PS is unable to produce a pressor response in the rabbit unless the sensitivity of the gangionic muscarinic receptors is altered by ganglionic nicotinic blockade, by the decrease of central sympathetic outflow on the sympathetic ganglia or by spinalization.

• Progress in Medical Physics
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• v.11 no.1
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• pp.29-38
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• 2000

The signal transduction pathway for most neurotransmitter induced inhibition of $Ca^{2+}$ channels in sympathetic neurons involves a G-protein mediated, membrane-delimited mechanism without the participation of any known protein kinase. However, activation of protein kinase C (PKC) has been proposed as one of the intracellular mechanisms mediating some neurotransmitter induced $Ca^{2+}$ channel inhibition. In the present study, we investigated the effects of phorbol-12, 13-dibutyrate (PDBu) on $Ca^{2+}$ channel currents of acutely dispersed neurons from adult rat superior cervical ganglion (SCG) neurons using whole cell variant of the patch clamp technique. PDBu (500 nM), the activator of PKC, increased $Ca^{2+}$ channel currents and retarded the deactivation of tail currents. The effects of PDBu were voltage dependent and the maximal increase in the current amplitudes was observed between -10 to 10 mV (n=4). PDBu attenuated $Ca^{2+}$ current inhibition induced by norepinephrine (NE), which modulates $Ca^{2+}$ channels via a pertussis toxin (PTX)-sensitive pathway. Inhibition of PDBu by staurosporine (1 $\mu$M) blocked the effects of PDBu on current amplitudes and NE-induced G-protein mediated inhibition of $Ca^{2+}$ currents. Further experiment should be done to know if G-protein or $Ca^{2+}$ channel itself is the target of PKC phosphorvlation.phosphorvlation.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.581-587
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• 2004

Conventional power spectrum methods based on FFT, AR method are not appropriate for analyzing biomedical signals whose spectral characteristics change rapidly. On the other hand, time-frequency analysis has more desirable characteristics of a time-varying spectrum. In this study, we investigated the spectral components of heart rate variability(HRV) in time-frequency domain using time frequency analysis methods. In the various time-frequency kernels functions, we studied the suitable kernels for the analysis of HRV using synthetic HRV signals. First, we evaluated the time/frequency resolution and cross term reduction of various kernel functions. Then, from the instantaneous frequency, obtained from time-frequency distribution, the method extracting frequency components of HRV was proposed. Subjects were 17 healthy young men. A coin-stacking task was used to induce mental stress. For each subjects, the experiment time was 3 minutes. Electrocardiogram, measured during the experiment, was analyzed after converted to HRV signal. In the results, emotional stress of subjects produced an increase in sympathetic activity. Sympathetic activation was responsible for the significant increase in the LF/HF ratio. Subjects were divided into two groups with task ability. Subjects who have higher mental stress have lack of task ability.

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.177-183
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• 1990

This study was undertaken to confirm whether or not the sympathetic nervous system takes part in the liver regeneration after partial hepatectomy. The male Sprague-Dawley rats were pretreated with I.P. injection of guanethidine 25 mg/kg: single dose (G-1); multiple doses once a day for 3 days (G-3), for 5 days (G-5), or for 6 days (G-6). The rats were subjected to partial hepatectomy $(70.4{\pm}1.99%)$ under light anesthesia of diethyl ether. 1) The systolic blood pressure of control rat was $98.0{\pm}3.9\;mmHg$ and was not affected by G-1. But after the pretreatment with G-3, G-5 or G-6, the pressure was markedly decreased by over 25 %. 2) Both of plasma norepinephrine and epinephrine levels showed the marked increases 3 hrs after the hepatectomy. However, the increases are entirely inhibited by G-1 or G-6. 3) All the liver contents of putrescine, spermidine and spermine showed the significant increases 6 hrs after the hepatectomy and were not affected by G-1 or G-6 with the exception of the inhibition of putrescine increase by only G-6. The present results suggest that the sympathetic activation appeared after partial hepatectomy seems not to play an important role in rat liver regeneration.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.4
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• pp.227-234
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• 2012

In this study, the masking effect of olfactory stimulus on the awakening state due to sound stimuli while driving using Graphic Driving Simulator was observed through the response of autonomic nervous system. The test was conducted for 11 males in their twenties. The siren of ambulance car was presented to them as auditory stimulus for 30 secs while driving in a situation of high way in the condition of both peppermint and control, respectively, and LF/HF ratio of HRV (Heart Rate Variability), the activity index of sympathetic nerve, and GSR (Galvanic Skin Response) response were examined. The test was proceeded in the order of three stages, that is, sound stimuli (test 1), driving performance, and sound stimuli (test 2), and fragrance stimulus, driving performance, and sound stimuli (test 3), and the physiological signal of GSR, HRV was measured in the whole stages. As a result of test, comparing the results of before and after auditory stimulus test (1) (p < 0.01), test (2) (p < 0.05), and test (3) (p < 0.01), driving performance test (2) (p < 0.01), test (3) (p < 0.01), and olfactory stimulus test (3) (p < 0.05), respectively, GSR response increased, showing significant difference in all the tests. It indicates that when auditory stimulus was presented to the subjects, they were in the awakening state as sympathetic nervous system got activated. As a result of comparing auditory stimulus while driving before and after presenting olfactory stimulus, there was no significant difference in GSR response. The LF/HF ratio of HRV increased, showing a significant difference only in test (2) (p < 0.05), and in driving performance test (2) (p < 0.05) in auditory stimulus, however, it showed no significant difference in olfactory stimulus. As a result of comparing auditory stimulus while driving before and after presenting olfactory stimulus, there was a decrease, showing significant difference (p < 0.05) in LF/HF ratio of HRV. That is, it means that the activation of sympathetic nervous system decreased, and that parasympathetic nervous system got activated. From these results, it was observed that while driving, the awakening level due to auditory stimulus was settled with olfactory stimulus. In conclusion, it was drawn that while driving, olfactory stimulus could have the masking effect on auditory stimulus.