• Journal of the Korean Regional Science Association
• /
• v.31 no.3
• /
• pp.79-97
• /
• 2015

This paper attempts to quantify the economic value of the recreational benefits from the Jangheung dam. To this end, the contingent valuation (CV) survey was administrated to a sample of randomly selected 1,000 households from the national population. We used single-bounded model as a method of eliciting the willingness to pay (WTP) and applied a spike model to deal with zero WTP responses (72.5%) from the CV survey. The respondents were asked to state whether to pay a given amount through additional higher income tax once a year for next ten years. The results show that the annual recreational benefits of the Jangheung dam are estimated to be 1,348 won per household, which is statistically significant at the 1% level. Expanding the value to the national population gives us 24.9 billion won per year.

• The Korean Journal of Physiology and Pharmacology
• /
• v.9 no.5
• /
• pp.263-268
• /
• 2005

Striatum has important roles in motor control, habitual learning and memory. It receives glutamatergic inputs from neocortex and thalamus, and dopaminergic inputs from substantia nigra. We examined effects of dopamine (DA) on the corticostriatal synaptic transmission using in vitro extracellular recording technique in rat brain corticostriatal slices. Synaptic responses were elicited by stimulation of cortical glutamatergic inputs on the corpus callosum and recorded in the dorsal striatum. Corticostriatal population spike (PS) amplitudes were decreased ($39.4{\pm}7.9$%) by the application of $100{\mu}M$ DA. We applied receptor subtype specific agonists and antagonists and characterized the modulation of corticostriatal synaptic transmission by different DA receptor subtypes. $D_2$ receptor agonist (quinpirole), antagonist (sulpiride), and $D_1$ receptor antagonist (SKF 83566), but not $D_1$ receptor agonist (SKF 38393), induced significantly the reduction of striatal PS. Pretreatment neither with SKF 83566 nor sulpiride significantly affected corticostriatal synaptic inhibition by DA. However, the inhibition of DA was completely blocked by pretreatment with mixed solution of both SKF 83566 and sulpiride. These results suggest that DA inhibits corticostriatal synaptic transmission through both $D_1$ and $D_2$ receptors in concert with each other.

• The Korean Journal of Physiology and Pharmacology
• /
• v.17 no.5
• /
• pp.405-409
• /
• 2013

We studied the sex different nicotine effect on evoked population spike amplitudes (ePSA) and connexin (Cx) expression in the hippocampus CA1 area of gerbils. Acute doses of nicotine bitartrate (0.5 mg/kg: NT-0.5) slightly reduced ePSA in males but markedly augmented that in females. Acute NT (5.0 mg/kg) markedly increased the ePSA in all gerbils. Unlike acute NT-0.5, repeated NT-0.5 injection (twice a day for 7 days) significantly increased the ePSA in males and slightly affected the NT-0.5 effect in females. The Cx36 and Cx43 expression levels as well as Cx expressing neuronal populations were significantly increased by repeated NT-0.5 in in both male and female gerbils, and particularly, Cx43 expression was somewhat prominent in females. These results demonstrated a sex difference with respect to the nicotine effect on hippocampal bisynaptic excitability, irrelevant to connexin expression.

• The Korean Journal of Physiology and Pharmacology
• /
• v.7 no.6
• /
• pp.295-301
• /
• 2003

Striatum plays a crucial role in the movement control and habitual learning. It receives an information from wide area of cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from raphe nuclei. In the present study, the effects of 5-HT to modulate synaptic transmission were studied in the rat corticostriatal brain slice using in vitro extracellular recording technique. Synaptic responses were evoked by stimulation of cortical glutamatergic inputs on the corpus callosum and recorded in the dorsal striatum. 5-HT reversibly inhibited coticostriatal glutamatergic synaptic transmission in a dose-dependent fashion (5, 10, 50, and $10{\mu}M$), maximally reducing in the corticostriatal population spike (PS) amplitude to $40.1{\pm}5.0$% at a concentration of $50{\mu}M$ 5-HT. PSs mediated by non-NMDA glutamate receptors, which were isolated by bath application of the NMDA receptor antagonist, d,l-2-amino-5-phospohonovaleric acid (AP-V), were decreased by application of $50{\mu}M$ 5-HT. However, PSs mediated by NMDA receptors, that were activated by application of zero $Mg^{2+}$ aCSF, were not significantly affected by $50{\mu}M$ 5-HT. To test whether the corticostriatal synaptic inhibitions by 5-HT might involve a change in the probability of neurotransmitter release from presynaptic nerve terminals, we measured the paired-pulse ratio (PPR) evoked by 2 identical pulses (50 ms interpulse interval), and found that PPR was increased ($33.4{\pm}5.2$%) by 5-HT, reflecting decreased neurotransmitter releasing probability. These results suggest that 5-HT may decrease neurotransmitter release probability of glutamatergic corticostriatal synapse and may be able to selectively decrease non-NMDA glutamate receptor-mediated synaptic transmission.

• IMMUNE NETWORK
• /
• v.23 no.4
• /
• pp.33.1-33.13
• /
• 2023

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been acknowledged as an effective mean of preventing infection and hospitalization. However, the emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) has led to substantial increase in infections among children and adolescents. Vaccine-induced immunity and longevity have not been well defined in this population. Therefore, we aimed to analyze humoral and cellular immune responses against ancestral and SARS-CoV-2 variants after two shots of the BNT162b2 vaccine in healthy adolescents. Although vaccination induced a robust increase of spike-specific binding Abs and neutralizing Abs against the ancestral and SARS-CoV-2 variants, the neutralizing activity against the Omicron variant was significantly low. On the contrary, vaccine-induced memory CD4⁺ T cells exhibited substantial responses against both ancestral and Omicron spike proteins. Notably, CD4⁺ T cell responses against both ancestral and Omicron strains were preserved at 3 months after two shots of the BNT162b2 vaccine without waning. Polyfunctionality of vaccine-induced memory T cells was also preserved in response to Omicron spike protein. The present findings characterize the protective immunity of vaccination for adolescents in the era of continuous emergence of variants/subvariants.

• Clinical and Experimental Vaccine Research
• /
• v.13 no.1
• /
• pp.35-41
• /
• 2024

Purpose: The effectiveness of coronavirus disease 2019 (COVID-19) vaccination schemes and the combination of vaccines of various platforms for administering booster doses is still being studied since it will depend on the population's response to vaccines. We aimed to evaluate the safety, protection, and immunogenicity of the Salvadorean population's third dose booster COVID-19 vaccine and the potential benefit of homologous vs. heterologous regimens. Materials and Methods: This is an analytical observational cohort study in a population aged 18 to 65 years that was primarily vaccinated with AstraZeneca, Sinovac, or Pfizer/BioNTech. Volunteers were recruited (n=223) and followed up for 3 months after receiving the 3rd vaccine (BNT162b2) as a booster. Adverse reactions were monitored, serum anti-spike immunoglobulin G (IgG) was assessed by chemiluminescence, and a polymerase chain reaction was carried out when subjects developed clinical signs. Results: The cohorts finally included 199 participants, and we observed only mild adverse effects in all cohorts. A significant increase in specific IgG levels was found after the booster dose in all cohorts. The heterologous scheme with Sinovac showed the greatest increase in antibody titer, and a decrease was observed in all participants after 3 months. During the follow-up period, 30 participants showed symptomatology compatible with COVID-19, but only four were laboratory-confirmed and they showed mild clinical signs. Conclusion: These findings indicate that the booster doses used were safe and promoted an immediate increase in immunogenicity, which decreased over time. The heterologous regimen showed stronger immunogenicity compared to the messenger RNA-based homologous scheme.

• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.6
• /
• pp.681-690
• /
• 1997

Loss of synaptic transmission and accumulation of extracellular $K^+([K^+]_O)$ are the key features in ischemic brain damage. Here, we examined the effects of several $K^+$channel modulators on the early ischemic changes in population spike (PS) and $[K^+]_o$ in the CA1 pyramidal layer of the rat hippocampal slice using electrophysiological techniques. After onset of anoxic aglycemia (AA), orthodromic field potentials decreased and disappeared in $3.3{\pm}0.22\;min$ $(mean{\pm}SEM,\;n=40)$. The hypoxic injury potential (HIP), a transient recovery of PS appeared at $6.0{\pm}0.25\;min$ (n=40) in most slices during AA and lasted for $3.3{\pm}0.43\;min$. $[K^+]_o$ increased initially at a rate of 0.43 mM/min (Phase 1) and later at a much faster rate (12.45 mM/min, Phase 2). The beginning of Phase 2 was invariably coincided with the disappearance of HIP. Among $K^+$ channel modulators tested such as 4-aminopyridine (0.03, 0.3 mM), tetraethylammonium (0.1 mM), NS1619 $(0.3{\sim}10\;{\mu}M)$, niflumic acid (0.1 mM), glibenclamide $(40\;{\mu}M)$, tolbutamide $(300\;{\mu}M)$ and pinacidil $(100\;{\mu}M)$, only 4-aminopyridine (0.3 mM) induced slight increase of $[K^+]_o$ during Phase 1. However, none of the above agents modulated the pattern of Phase 2 in $[K^+]_o$ in response to AA. Taken together, the experimental data suggest that 4-aminopyridine-sensitive $K^+$channels, large conductance $Ca^{2+}-activated$ $K^+$ channels and ATP-sensitive $K^+$ channels may not be the major contributors to the sudden increase of $[K^+]_o$ during the early stage of brain ischemia, suggesting the presence of other routes of $K^+$ efflux during brain ischemia.

• Journal of Soil and Groundwater Environment
• /
• v.21 no.6
• /
• pp.156-168
• /
• 2016

The Korean government is planning to invest a lot of funds for conservation of the soil. Accordingly, it needs quantitative information on the soil. This paper attempts to analyze the total value of soil quantitatively: the total economic value of soil can be divided into use value and non-use value. To this end, we apply a replacement cost method (RCM) and contingent valuation method (CVM). Especially, CVM is most widely used to measure the non-use value such as environment goods. We employed the one-and-one-half-bounded dichotomous choice (OOHBDC) for willingness to pay (WTP) elicitation and a spike model. The monthly mean WTP was estimated to be KRW 3,949 per household for the next 10 years, which is statistically significant at the 1% level. Expanding the value to the relevant population gives us KRW 897.9 billion per year and as of the end of 2015, the non-use value of soil was assessed to be KRW 838.6 billion. Meanwhile, use value is subdivided into direct use value and indirect use value. This value was calculated KRW 3,277 trillion and KRW 51.8 trillion, respectively. As a result, total economic value of soil is estimated to be KRW 3,330 trillion in Korea.

• Toxicological Research
• /
• v.17
• /
• pp.257-261
• /
• 2001

Recently, a traditional medicine called Gouteng-san, which consists of eleven herbs, was reported to be effective in treating vascular dementia with a double-blind, placebo-controlled study. Gout-eng-san is also used for patients with vascular dementia in combination with Si-Wu-Tang. The effect of Gouteng-san and Si-Wu-Tang on deficit of learning behavior was investigated using step-down passive avoidance task in mice. Hot-water extract of Gouteng-san (1.5 and 6 g/kg, p.o.) significantly prolonged the step-down latency shortened by scopolamine. The extract of Uncaria hook (150 mg/kg, p.o.), one of the component herb of Gouteng-san, significantly prevented the decrease in the latency after scopolamine. Hot-water extract of Si-Wu-Tang (1.5 and 6 g/kg of dried herbs, p.o.) prevented dose-dependently scopola-mine-induced disruption qf learning behavior. Si-Wu-Tang also prevented the ischemia-induced deficit of learning behavior. Both hot water extract of peony and angelica (1.5 g/kg, p.o.), which are component herbs qf Si-Wu-Tang, prevented the scopolamine-induced learning behavior deficit. Scopolamine (10 uM) suppressed long-term potentiation (LTP) of population spike in the CA1 region of the rat hippocampal slices. Peoniflorin (0.1~ 1uM) extracted from paeony root significantly ameliorated scopolamine-induced inhibition of LTR These results suggest that improvement of deficit of learning behavior by Gouteng-san and Si-Wu-Tang is mediated by direct and/or indirect activation of the cholinergic system in the brain.

• The Korean Journal of Ecology
• /
• v.28 no.2
• /
• pp.99-103
• /
• 2005

Actual vegetation map drown with the scale 1 to 100 and Alnus japonica population in Ja-neup and Woong-neup of the Mujechi moor were described in order to monitor long-termly and preserve permanently, where is a very rare Molinietea moor and a legally protected area. A total of 3036 plots of 5m $\times$ 5m were surveyed during summer 1996. Thiessen polygons of 1491 alder trees were derived from the plot data. Actual vegetation map was illustrated by 6 cover types such as needle spike-rush type, moor-grass type, alder-moor type, eulalia type, oak forest type, and exposed site. Molinia grasses native to the moor and Miscanthus grasses alien to the moor are reciprocally dominant. The area of Molinia grasslands was rapidly in decline and alder population size was dramatically in increase in the moor, particularly in Woong-neup. In Molinietea moor preservation more attention should be focused on the regulation of a nutrient rich soil from forest road and fire.