Analysis of the current status of medical humanities education at domestic medical schools and proposal of educational system / 의료커뮤니케이션

The educational development in Korean Medical School has shown remarkable results in about 20 years. These institutes has an excellent evaluation base and educational independence. And the curriculum, the method, and the evaluation in medical education have been innovated over recent 20 years. Those revolutionary outcome of the innovation of medical education affirms possibilities and potentialities of innovation and reformation in the future. In response, this article attempted to reflect on the deficiencies of medical education through the analysis of the educational status of medical humanities in 40 medical schools for better future medical humanities education under such a strong environment. Therefore, the purpose of this article is to present the direction in which medical humanities literature based on value education. In this process, in order to find the essence of medical education through educational philosophy discourse, the blue print of evidence based medicine is presented, and the role and direction of medical humanities are suggested through reflection on strengthening medical education capabilities.

The Efficacy of Posterior Turbinoplasty in Combination with Tonsillectomy and Adenoidectomy in Pediatric Sleep Disordered Breathing Patients / 대한이비인후과학회지

Background and Objectives@#Tonsillectomy and adenoidectomy (T&A) are effective for the treatment of pediatric sleep disorder breathing. However, in some pediatric patients, there remain unresolved snoring and mouth breathing problems after the operation. This study is aimed at evaluating the efficacy of coblation of hypertrophic posterior turbinate in combination with tonsillectomy and adenoidectomy.Subjects and Method We analyzed data from 50 children aged between 5 to 13 years old who were scheduled to undergo T&A operation from June 2018 to December in 2018. We randomly divided them into two groups. The first group consisted of 25 patients who were scheduled to perform only tonsillectomy and adenoidectomy. The second group was 21 patients who were scheduled to perform posterior turbinoplasty in combination with tonsillectomy and adenoidectomy. We evaluated preoperative and postoperative polysomnogram [Apnea-Hypopnea Index (AHI), O2 saturation], acoustic rhinometry (minimal cross section area, nasal volume), and Korean Obstructive Sleep Apnea-18 Survey (KOSA-18) score. @*Results@#After additional turbinoplasty (coblation of hypertrophic posterior turbinate), the rate of snoring and mouth breathing remaining was decreased. There were significant improvements in AHI, oxygen saturation, Visual Analog Scale and Epworth Sleepiness Scale in two groups. Symptoms (snoring and mouth breath) remaining postoperatively was much more decreased in the posterior turbinoplasty combined with T&A group than in the single T&A group in terms of KOSA-18. @*Conclusion@#When it comes to pediatric sleep disorder breathing surgery, nasal cavity evaluation is an important factor for patient’s postoperative satisfaction for sleeping and snoring. For pediatric sleep disorder breathing patients with hypertrophic posterior turbinate, who are scheduled to do tonsillectomy and adenoidectomy, an additional coblation of posterior turbinate should be considered.

Effect of Filmogen Topical Gel on Pain and Hemorrhage after Tonsillectomy / 대한이비인후과학회지

Background and Objectives@#Tonsillectomy is one of the most common operative procedures in otorhinolaryngology. Most patients following tonsillectomy suffer from postoperative pain and hemorrhage. This study was performed to investigate whether filmogen topical gel (PHARGELⓇ, Vitrobio SAS), applied to the tonsillectomy site after tonsillectomy reduced pain and hemorrhage.Subjects and Method A total of 40 patients over 15 years old scheduled for elective tonsillectomy were randomly divided into two groups. After tonsillectomy and postoperative day 0, 1, 2, and 7, one group was applied with the filmogen topical spray 3-5 times a day but the other group remained without applying it. Pain and postoperative hemorrhage were measured at the postoperative day 0, 1, 2, and 7 of the operation. Pain was measured by using a visual analogue scale. @*Results@#Patients who applied the filmogen topical spray presented lower pain scores than patients who didn’t applied the spary. There was no difference for postoperative hemorrhage between two groups. @*Conclusion@#Filmogen topical spray is an effective postoperative control for pain but not for hemorrhage on the tonsillectomy site.

Recent Insights into Insulin-Like Growth Factor Binding Protein 2 Transcriptional Regulation

Insulin-like growth factor binding proteins (IGFBPs) are major regulators of insulin-like growth factor bioavailability and activity in metabolic signaling. Seven IGFBP family isoforms have been identified. Recent studies have shown that IGFBPs play a pivotal role in metabolic signaling and disease, including the pathogenesis of obesity, diabetes, and cancer. Although many studies have documented the various roles played by IGFBPs, transcriptional regulation of IGFBPs is not well understood. In this review, we focus on the regulatory mechanisms of IGFBP gene expression, and we summarize the findings of transcription factor activity in the IGFBP promoter region.

Annual Report on the External Quality Assessment Scheme of Viral Markers and Serological Tests for Syphilis in Korea (2015)

As the Immunoserology Subcommittee of the Korean Association of External Quality Assessment, we organized two trials on the external quality assessment of viral markers and serological tests for syphilis (STS) in 2015. For this purpose, we delivered three kinds of pooled sera specimens for external proficiency testing to 1,071 and 1,074 institutions for the first and second trials, respectively. Pooled sera were checked for their homogeneity and stability using multiple methods between the day of their manufacture and three days after dispatching. The number of participating laboratories was 1,055 (98.5%) and 1,055 (98.2%) in the first and second trial, respectively. The most commonly tested items were hepatitis B surface antigen, followed by the antibodies to hepatitis B surface antigen, antihuman immunodeficiency virus, anti-hepatitis C virus, STS, and anti-hepatitis B core. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay (CLIA) and the electrochemiluminescence immunoassay, which were found to generate few false positive results. In contrast, false negative results were frequently found when the immunochromatographic assay (ICA) was used; the use of ICA for detecting viral markers has been steadily increasing in recent years. Furthermore, the use of turbidoimmunoassay and CLIA, tests recently introduced for the measurement of nontreponemal and treponemal antibodies, is also increasing.

Annual Report on the External Quality Assessment Scheme of Viral Markers and Serological Tests for Syphilis in Korea (2014)

As Immunoserology Subcommittee of the Korean Association of External Quality Assessment Service, we organized two trials on the external quality assessment of viral markers and serological tests for syphilis (STS) in 2014. For this purpose, we delivered three kinds of pooled sera specimens for external proficiency testing to 1,060 and 1,064 institutions for the first and second trials, respectively. Pooled sera were checked for their homogeneity and stability by using more than three other methods between the day of their manufacture and 3 days after despatching. The numbers of participating laboratories were 1,053 (99.3%) and 1,046 (99.3%) in the first and second trials, respectively. The most commonly tested items were hepatitis B surface antigen, followed by antibody to hepatitis B surface antigen, anti-human immunodeficiency virus, anti-hepatitis C virus, STS, and anti-hepatitis B core. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay (CLIA) and the electrochemiluminescence immunoassay, which generated few false positive results. In contrast, false negative results were frequently found through the immunochromatography assay, the use of which for detecting viral markers has been steadily increasing in recent years. Furthermore, the use of turbidoimmunoassay and CLIA, which are new tests recently introduced for the measurement of non-treponemal and treponemal antibodies, is also increasing.

Annual Report on External Quality Assessment of Viral Markers and Serological Tests for Syphilis in Korea (2013) / 임상검사와정도관리

We performed two trials on the external quality assessment of viral markers and serological tests for syphilis (STS) organised by the Immunoserology Subcommittee of the Korean Association of Quality Assurance for Clinical Laboratories in 2013. In each trial, we delivered 3 kinds of pooled sera specimens to 1,021 institutions for external proficiency testing. Pooled sera were checked for their homogeneity and stability by using more than 3 other methods between the day of their manufacture and 3 days after despatching. The numbers of participating laboratories were 1,019 (99.8%) and 1,020 (99.8%) for the first and second trials, respectively. The most commonly tested items were hepatitis B surface antigen followed by antibody to hepatitis B surface antigen, anti-human immunodeficiency virus, anti-hepatitis C virus, STS, and anti-hepatitis B core. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay (CLIA) and the electrochemiluminescence immunoassay, which generated a few false positive results. In contrast, false negative results were frequently found through the immunochromatography assay, the use of which for detecting viral markers has been steadily increasing in recent years. The new tests, turbidoimmunoassay and CLIA, have recently been introduced for the measurement of non-treponemal and treponemal antibodies, and their use is also increasing.

Historical Study on Factors Inducing Soil-Transmitted Helminth Infection among People of Old Seoul City during Joseon Dynasty / 의사학

In a series of paleo-parasitological investigations, we have been able to obtain invaluable data on parasite infection patterns prevalent among the Joseon (1392-1910) people in Korea. Thus far we have established that the Joseon people were in fact heavily infected by various species of parasites, though precise patterns and exact statuses of infection in specific town and cities have proved elusive. In the present study, relevant historical documentation was obtained and examined, shedding light on some of the operative socio-cultural factors that might have played a role in inducing a high infection prevalence of Ascaris, a soil-transmitted roundworm, in Joseon society. On this evidentiary basis, we could confirm that the recycling of human feces as fertilizer and the habit of eating raw vegetables were both closely related to infection. These factors were sufficient to maintain the life cycle of Ascaris, there by perpetuating a cycle of infection and reinfection among the Joseon inhabitants. Overall, this study demonstrated the value of close medical-scientist / historian interdisciplinary collaboration infacilitating comprehensive and meaningful paleo-parasitological findings and interpretations.

Effect of Developmental Lead Exposure on the Expression of Hippocampal NMDA Receptor Subunit mRNA / 대한산업의학회지

OBJECTIVES: The purpose of the present study was to examine the differential effects of lead (Pb) exposure on the expression of specific NMDA receptor subunit mRNAs on the hippocampal cells depending on the neuronal developmental stage. METHODS: Expression of the NR2A and NR2B subunits of the NMDA receptors mRNA on the hippocampal neurons was measured by in situ hybridization in the control and Pb treated groups. Pb-treated and NMDA cytotoxicity was assessed by morphological examination and LDH measurements. RESULTS: Hippocampal NR2A subunit mRNA expression was gradually increased with increasing age, and was significantly decreased after Pb exposure. The expression of NR2B subunit mRNA was not changed during development in the rat hippocampus and the developmental effect of Pb exposure on NR2B expression was minimal. These results indicate that chronic Pb exposure may decrease the levels of NR2A-containing NMDA receptors and may thereby alter normal synaptic signal transmission. Pb or NMDA-induced cytotoxicity in vitro differed significantly between the immature and the mature hippocampal cells. CONCLUSIONS: This study demonstrates that chronic Pb exposure during brain development alters the levels of specific NMDA receptor subunit mRNA in the rat hippocampus. These results suggest that chronic Pb exposure may attenuate the precise neuronal synaptic transmission through the differential alteration of the composition of the NMDA receptor subunit on the hippocampus depending on neuronal developmental stage.

Relationship between Mitochondrial DNA Point Mutation and Noise-induced Sensorineural Hearing Loss / 항공우주의학회지

BACKGROUND: A different sequence change in the mitochondrial 12S rRNA gene has been proposed as a candidate mutation in the sensorineural hearing loss. The purpose of this study was to study the association between the noise-induced sensorineural hearing loss and A to G mutation at nucleotide 1555 of mitochondrial DNA. METHODS: subjects were reviewed by history and medical records, and audiological and clinical data were obtained. Blood sampling was done on 101 normal controls, 51 with noise-induced sensorineural hearing loss, and 12 with sensorineurnal deafness. The DNA of these individuals were extracted, and mitochondrial genome were analyzed by polymerase chain reaction (PCR). Subsequently, the coding sequence of mitochondrial genome was sequenced and compared to the normal sequence, and all sequence variations were analyzed by restriction endonuclease BsmA I. RESULTS: Mitochondrial DNA mutant (1555A-->G) was not detected by PCR in all Korean patients with noise-induced hearing loss, sensorineural hearing loss, and in normal controls with no hearing loss. The DNA sequencing of PCR products did not reveal an A to G substitution at nucleotide 1,555 of mitochondrial DNA. CONCLUSION: This result suggests that the noise-induced sensorineural hearing loss is not associated with mitochondrial DNA mutation (1555A-->G).

Regulation of Natriuretic Peptide Family mRNA Induced by Head-down Suspension in Rats / 항공우주의학회지

BACKGROUND: Head-down suspension (HDS) of rats has been used as a model for the simulation of a microgravity environment. Natriuretic peptide family including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptides (CNP), and their receptors are responsible for body fluid homeostasis and blood pressure control. However, little is known about the long-term responses and the simultaneous observations of both natriuretic peptide family and their receptors following HDS. This study was analyzed the regulation of cardiac, hypothalamic and renal natriuretic peptides and their receptors syntheses to 4 weeks of HDS in rats. METHODS: Unanesthetized, unrestrained, male Sprague-Dawley rats were subjected to either a horizontal position (control rats) or a -45degrees head-down tilt using the tail-traction technique (HDS rats). This study observed the cardiac, hypothalamic and renal syntheses of natriuretic peptides as a expression of ANP, BNP and CNP mRNA. The mRNA expressions of A-type natriuretic peptide receptor (NPR-A), B-type NPR (NPR-B) and clearance receptor (NPR-C) were also determined. The expressions of natriuretic peptide and their receptor mRNA were measured by reverse transcription-polymerase chain reaction with [32P]-dCTP following 4 weeks of HDS in both control and HDS rats. RESULTS: After 4 weeks of HDS, the expressions of ANP mRNA were significantly decreased in the right atrium and the kidney, and showed the non-significant decreasing trend in the left atrium and the hypothalamus of HDS rats. BNP mRNA expressions were decreased in the heart especially in the left atrium, while its mRNA in the left ventricle was showed the non-significant increasing trend following 4 weeks of HDS. The expressions of CNP mRNA were increased in the hypothalamus and showed the non-significant increasing trend in the kidney of the HDS rats. After 4 weeks of HDS, NPR-A mRNA expressions were decreased in the kidney and hypothalamus, but NPR-C mRNA expression was showed the non-significant increasing trend in the kidney of HDS rats compared with controls. CONCLUSION: These results suggest that the regulation of natriuretic peptide mRNA following 4 weeks of HDS exerts to maintain the blood volume through an attenuation of syntheses in natriuretic peptide family of the heart and the kidney.

Changes in Renal Expression of Natriuretic Peptides and Their Receptors mRNA Induced by Head-down Suspension in Rats

BACKGROUND: Head-down suspension (HDS) of rats has been used as a model for the simulation of a microgravity environment. Atrial natriuretic peptide (ANP), C-type natriuretic peptides (CNP) and their receptors are found in the kidney, suggesting that these peptides could play a significant physiological role in the kidney. Therefore, this study was investigated the changes in the adaptations of renal natriuretic peptides and their receptors syntheses after 4 weeks of HDS in rats. METHODS: Unanesthetized, unrestrained, male Sprague-Dawley rats were subjected to either a horizontal position (control rats) or a -45degreeshead-down tilt using the tail-traction technique (HDS rats). This study observed the renal syntheses of natriuretic peptides as a expression of ANP and CNP mRNA, and also determined the expression of A-type natriuretic peptide receptor (NPR-A) mRNA and B-type NPR (NPR-B) mRNA. The expressions of natriuretic peptide and NPR mRNA were measured by reverse transcription-polymerase chain reaction with [(32)P]-dCTP following 4 weeks of HDS in the kidney of both control and HDS rats. RESULTS: After 4 weeks of HDS, the expression of ANP mRNA significantly (P<0.01) decreased, while CNP mRNA expression was showed the non-significant increasing trend in the kidney of HDS rats. NPR-A, which binds with ANP, was significantly (P<0.001) decreased in renal mRNA expression of HDS rats compared with controls. Expression in mRNA of NPR-B, which binds with CNP, showed a slightly decreasing trend in the kidney of rats following HDS. CONCLUSION: These results suggest that the renal adaptation following 4 weeks of HDS exerts to maintain the blood volume and electrolyte balance through attenuation of syntheses in the natriuretic peptide and its binding receptor, especially in ANP rather than in CNP systems.

Manganese Cytotoxicity Mediated by Potentiation of Nitric Oxide Production in Activated Glial Cell

BACKGROUND: Glial cells are generally known to support normal neuronal functions tightly regulating the extracellular environment and providing energy substrates such as glucose. Therefore, dysfunction or loss of glial cells will lead to neuonal death. Since manganese (Mn2+) is known to be sequestered in glial cells, we investigated whether nitric oxide (NO) production in the activated glial cells is potentiated by manganese and the relationship between increased NO production and manganese-induced cytotoxicity of glial cells. METHODS: Manganese toxicity was assessed by morphological examination and by measuring the release of lactate dehydrogenase. Cultured glial cells were stimulated by lipopolysaccharide (1mug/mL). NO production was determined by measuring nitrites, a stable oxidation product of NO. RESULTS: Neither a LPS nor a MnCl2 altered the viability of glial cells. A 24 hr stimulation both LPS and MnCl2, however, markedly potentiated the manganese-induced death of glial cells. Manganese significantly increased the bacterial LPS-induced NO production. Manganese-induced NO release was markedly reduced by NOS inhibitor N(G)-nitro-L-arginine (L-NNA, 1 mM), and potentiation of manganese-induced cell death by activated glial cells was partially prevented by L-NNA. CONCLUSION: It is concluded that manganese could induce sustained production of neurotoxic nitric oxide by the activated glial cells and manganese-induced cytotoxicity is partially mediated by potentiation of LPS-induced nitric oxide in the glial cell culture model.

Changes in Hypothalamic Expressions of Natriuretic Peptide mRNA following Head-down Suspension in Rats

BACKGROUND: Head-down suspension (HDS) of rats has been used as a model for simulation of a microgravity environment. C-type natriuretic peptides (CNP) and atrial natriuretic peptide (ANP) are produced in the central nervous system, especially in hypothalamus, to complement their peripheral natriuretic effects. Therefore, this study investigated the changes in the central adaptations of hypothalamic ANP and CNP syntheses to 4 weeks of HDS in rats. METHODS: Unanesthetized, unrestrained, male Sprague-Dawley rats were subjected to either a horizontal position (control rats) or a -45 degrees head-down tilt using the tail-traction technique (HDS rats). We determined the hypothalamic syntheses of natriuretic peptides as an expression of ANP and CNP mRNA. The expression of natriuretic peptide mRNA was measured by reverse transcription-polymerase chain reaction with [32P]-dCTP following 4 weeks of HDS in the hypothalamus of control and HDS rats. RESULTS: After 4 weeks of HDS, the expression of ANP mRNA showed a decreasing trend in the hypothalamus of HDS rats. In contrast with ANP, CNP mRNA expression was significantly (p<0.01) increased in the hypothalamus of HDS rats. There were different changes in the hypothalamic CNP and ANP mRNA expressions of HDS rats compared with that of the control rats.CONCLUSION: These results represent that the hypothalamic syntheses of natriuretic peptides are differently responded and the role of CNP is augmented to compensate for the decrement of ANP action in the central nervous system following 4 weeks of HDS.

Effects of Long-Term Head-down Suspension on Changes in Body Weight, Daily Water Intake and Hematological Data in Rats

BACKGROUND: This study was aimed to observe the changes in body weight, water intake and hematological data during and after long-term head-down suspension (HDS) in rats. HDS rats induced by tail suspension has evolved as a useful model for the simulation of a microgravity or zero-gravity environment. METHODS: Unanesthetized, unrestrained, male Sprague-Dawley rats, weighing 230-270 g, were subjected to either a hori-zontal position (control horizontal, CH rats) or a 45 degreeshead-down suspension (HDS rats) for 4 weeks. We deter-mined the body weight and daily water intake in both CH and HDS rats. Hematological data including white and red blood cell counts, hemoglobin concentration and hematocrit were measured. The characteristics of red blood cell were also calculated from above hematological data in the both rats after 4 weeks of observa-tion. RESULT: In CH rats, body weight was significantly increased (P<0.05) after 4 weeks of experiment, where-as the body weight of HDS rats was only showed a small increase but was significantly decreased (P<0.05) after 4 weeks of HDS compared with that of CH rats. Daily water intake was increased (P<0.05) after 2 week in HDS rats but the overall changes of the rest period were no difference between both CH and HDS rats. White blood cell counts did not show any changes in both rat groups while red blood cell counts showed a decreas-ing trend after 4 weeks HDS. After HDS, hemoglobin concentration, hematocrit and mean corpuscular hemoglobin were significantly decreased (P<0.05) compared with CH rats. CONCLUSION: These results represent that the long-term HDS could attenuate the increase in body weight of young rats and induce the decrease in hemato-logical data, especially in the characteristics of red blood cell.

Effects of Endothelin on Potassium Currents in Primary Cultured Rat Microglia

BACKGROUND: Endothelin (ET), potent vasoconstricting peptide, are produced by endothelial cells after brain insults such as ischemia or infection and may play a role in the amplification or regulation of the microglia. In pathology of central nervous system, microglia might become activated leading to altered cellular function in response to brain injury. METHODS: Whole-cell patch clamp technique was used to study the effects of endothelin on changes of potassium currents in cultured rat microglia. Outward and inward rectifying potassium currents were recorded after application of depolarization and hyperpolarization pulses from -60 mV holding potential, respectively. RESULT: ET (100 nM) decreased the amplitude of outward rectifying potassium current and ET-3 was the most potent isoform. Both amplitude and slope conductance of inward rectifying potassium current were increased by ET. After application of ET, the reversal potential of inward potassium current was shifted to left relative to control. CONCLUSION: These results suggest that ET changes the potassium currents and membrane potential of microglia and this depolarizing effect of ET is related with the activation of microglia under pathological conditions of brain

Changes of mRNA and Plasma Levels of Atrial Natriuretic Peptide in Subtotal Nephrectomized Rats after High Salt Intake / 대한신장학회잡지

High salt intake produces volume expansion and electrolyte imbalance in chronic renal failure and modifies the synthesis and secretion of atrial natriuretic peptide(ANP) to compensate the abnormalities in fluid and sodium handling. This study was performed to investigate the effect of high salt intake on modulation of cardiac and noncardiac ANP mRNA as well as plasma ANP levels in 5/6 subtotal nephrectomized (NPX) rats as a model of chronic renal failure. Adult male Sprague-Dawley rats were divided into sham and NPX rats. NPX rats were induced by 2/3 pole ligation and contralateral nephrectomy. Sham and NPX rats had access to normal chow with tap water for 8 weeks or normal chow with 0.45% NaCl solution(HS) for last 2 weeks. Plasma ANP levels were measured by radioimmunoassay. ANP mRNA from the right atrium, left ventricle, hypothalamus and kidney were analyzed by RT-PCR with 32P-dCTP at 8 weeks after surgical operation in both sham and NPX rats. Blood urea nitrogen(BUN) was measured to evaluate impaired renal function. Body weight, daily water intake, hemoglobin, red blood cell, hematocrit, arterial pressure and heart rate were also monitored. Arterial pressure in NPX+HS rat was significantly increased. Both percent increase of body weight and hematologic findings were decreased in NPX rats. Daily water intake was increased in NPX rats, especially in NPX+HS rat. BUN also increased in NPX rats. Plasma ANP concentration was significantly increased in sham+HS rat, but other significant increases were not shown in NPX rats. The levels of right atrial ANP mRNA represented the increasing trend like as plasma ANP. Left ventricular ANP mRNA was increased in sham+HS rat, while the level in NPX+HS rat was decreased comparing with that of sham+HS rat. Hypothalamic ANP mRNA was decreased in NPX+HS rat. In the kidney, the level of ANP mRNA in sham+HS rat was increased comparing with sham rat, but ANP synthesis in NPX+HS rat was significantly lower than in sham, sham+HS and in NPX rats. These findings represent that the high salt intake in NPX rat does not alter the plasma levels and cardiac synthesis of ANP but suppresses the renal ANP mRNA. The diminished renal ANP synthesis may attenuate the regulatory role of ANP system in the kidney and result in volume expansion and hypertension.

Mechanism of Renal Oxidative Damage following 4-week Head-down Suspension in Rats

The purpose of this study was to observe the variation of malondialdehyde (MDA), an indirect index of oxidative damage, following 4-week of head-down suspension (HDS) at -45degreein rats as a model of simulated weightlessness. We also measured the activities of antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase for clarifying the mechanisms of renal oxidative damage. MDA was increased (p<0.05) at the 4th week of HDS rats compared to control horizontal positioned rats. Following HDS, the renal activity of SOD was also significantly increased (p<0.01) at the 4th week of HDS whereas the changes of renal GSH-Px and catalase activities were not significantly different from controls. The expression of renal SOD mRNA used by polymerase-chain reaction method showed the similar pattern with the change of renal SOD activity and was more increased (p<0.05) than control horizontal positioned rat. These results indicate that simulated weightlessness induces the augmented SOD gene expression in the kidney which results in increased SOD activity, and thus increased production of MDA due to increased production of hydrogen peroxide. And under this condition, GSH-Px and catalase do not play their protective roles against hydrogen peroxide.

Effects of Propofol in Voltage-dependent Potassium Channels in Human Neurl Stem Cells

BACKGROUND: Human neural stem cells have at least two types of voltage-dependent potassium channels including inward and outward rectifying potassium channels. Data for the effects of propofol, intravenous anesthetics, on human neural potassium channels are limited. We have examined the effects of propofol on voltage-dependent potassium channels in human neural stem cells. METHODS: Voltage-dependent potassium currents were measured in cultured human neural stem cells using the whole cell patch-clamp technique before and after application of 0.1 mM propofol. Inward and outward rectifying potassium currents were elicited by hyperpolarizing and depolarizing step pulses from -60 mV holding potential, respectively. RESULTS: Propofol was found to reversibly block the outward rectifying potassium current (p<0.05), while the anesthetics did not alter the characteristics of inward rectifying potassium current. The blocking effect of propofol on outward rectifying current was voltage-dependent and enhanced at depolarization potentials above +30 mV (p<0.05). Propofol also decreased the slope conductance of outward potassium current (p<0.05). CoNCLUSION: These results show that propofol may strongly affect the outward potassium channels in human neural stem cells and also suggest a need for investigation into the effect of propofol on the functional regulation of human neural stem cells.

Expression of Atrial and Extra-atrial ANP mRNA in Rats with Chronic Renal Failure / 대한신장학회잡지

Chronic renal failure(CRF) may lead to fluid retention and electrolyte imbalance, and consequently increases the extracellular volume and blood pressure. These changes can trigger secretion and synthesis of atrial natriuretic peptide(ANP) as a compensatory regulator for increases in the glomerular filtration rate and excretion of water and sodium due to the reduced number of functional nephrons. ANP may exert important regulatory role on body fluid balance and blood pressure in CRF. We assessed changes in gene expression of atrial and extra-atrial ANP associated with progression of renal failure in subtotal nephrectomized rats. Adult male Sprague-Dawley rats were divided into sham and CRF rats. CRF rats were induced by 5/6 subtotal nephrectomy. We determined the plasma ANP level using by radioimmunoassay and the ANP mRNA from the right atrium, left ventricle, hypothalamus and kidney were measured by reverse transcription-polymerase chain reaction with 32P- dCTP at 8 wk in sham, and at 8 and 12 wk in CRF rats. Serum urea nitrogen(SUN) was also checked as an indicator of impaired renal function. SUN was significantly increased in CRF rats and the level was higher at CRF 12 wk rat than CRF 8 wk rat. Plasma concentration of ANP also increased in CRF rats compared with sham rat, but was not statistically significant. Altered patterns of ANP mRNA expression were different in each tissue. Right atrial and renal ANP mRNA expressions were slightly increased in CRF rats. Left ventricular ANP mRNA was significantly increased in CRF 8 wk rat compared with sham rat and maintained high at CRF 12 wk rat. However hypothalamic ANP mRNA expressions at CRF rats were decreased and the expression in CRF 12 wk was significantly lower than that at CRF 8 wk. SUN showed positive correlations with expression in left ventricular and renal ANP mRNA, but had a significant negative relationship with hypothalamic ANP mRNA. Plasma ANP concentration was positively correlated with the ANP mRNA expressions in both right atrium and kidney. The present study demonstrated that ANP mRNA in the right atrium, left ventricle, kidney and hypothalamus were differentially expressed upon CRF. This suggests that roles of the local ANP in these tissues are regulated by different mechanisms to compensate the fluid and electrolyte imbalance in rats with experimental chronic renal failure.