• Journal of Pharmaceutical Investigation
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• v.23 no.1
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• pp.1-9
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• 1993

The endothelial cell of brain capillary called the blood-brain barrier (BBB) has carrier-mediated transport systems for nutrients and drugs. The mechanism of the BBB transport of basic and acidic drugs has been reviewed and examined for endogenous transport systems in BBB in WKY and SHRSP. Acidic drugs such as salicylic acid and basic drugs such as eperisone are taken up in a carrier mediated manner through the BBB via the monocarboxylic acid and amine transport systems. The specific dysfunction for the choline transport at the BBB in SHRSP would affect the function of the brain endothelial cell and brain parenchymal cell. The utilization of the endogenous transport systems of monocarboxylic acid and amine could be promising strategy for the effective drug delivery to the brain.

• BMB Reports
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• v.39 no.4
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• pp.339-345
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• 2006

The blood-neural barrier (BNB), including blood-brain barrier (BBB) and blood-retinal barrier (BRB), is an endothelial barrier constructed by an extensive network of endothelial cells, astrocytes and neurons to form functional 'neurovascular units', which has an important role in maintaining a precisely regulated microenvironment for reliable neuronal activity. Although failure of the BNB may be a precipitating event or a consequence, the breakdown of BNB is closely related with the development and progression of CNS diseases. Therefore, BNB is most essential in the regulation of microenvironment of the CNS. The BNB is a selective diffusion barrier characterized by tight junctions between endothelial cells, lack of fenestrations, and specific BNB transporters. The BNB have been shown to be astrocyte dependent, for it is formed by the CNS capillary endothelial cells, surrounded by astrocytic end-foot processes. Given the anatomical associations with endothelial cells, it could be supposed that astrocytes play a role in the development, maintenance, and breakdown of the BNB. Therefore, astrocytes-endothelial cells interaction influences the BNB in both physiological and pathological conditions. If we better understand mutual interactions between astrocytes and endothelial cells, in the near future, we could provide a critical solution to the BNB problems and create new opportunities for future success of treating CNS diseases. Here, we focused astrocyte-endothelial cell interaction in the formation and function of the BNB.

• Childhood Kidney Diseases
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• v.19 no.2
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• pp.65-70
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• 2015

It is well known that proteins present in the primary urine are reabsorbed in the renal proximal tubules, and that this reabsorption is mediated via the megalin-cubilin complex and the neonatal $Fc{\gamma}$ receptor. However, the reabsorption is also thought to be influenced by an electrostatic interaction between protein molecules and the microvilli of the renal proximal tubules. By analyzing the charge diversity of urinary IgG, we showed that this reabsorption process occurs in a cationic charge-preferential manner. The charge-selective molecular sieving function of the glomerular capillary walls has long been a target of research since Brenner et al. demonstrated the existence of this function by a differential clearance study by using the anionic dextran sulfate polymer. However, conclusive evidence was not obtained when the study was performed using differential clearance of serum proteins. We noted that immunoglobulin (Ig) A and IgG have similar molecular sizes but distinct molecular isoelectric points. Therefore, we studied the differential clearance of these serum proteins (clearance IgA/clearance IgG) in podocyte diseases and glomerulonephritis. In addition, we studied this differential clearance in patients with Dent disease rather than in normal subjects because the glomerular sieving function is considered to be normal in subjects with Dent disease. Our results clearly showed that the charge-selective barrier is operational in Dent disease, impaired in podocyte disease, and lacking in glomerulonephritis.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.4
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• pp.246-251
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• 2003

The blood-brain barrier (BBB) is composed of the brain capillaries, which are lined by endothelial cells displaying extremely tight intercellular junctions. Several attempts at creating an in vitro model of the BBB have been met with moderate success as brain capillary endothelial cells lose their barrier properties when isolated in cell culture. This may be due to a lack of recreation of the in vivo endothelial cellular environment in these models, including nearly constant contact with astrocyte foot processes. This work is motivated by the hypothesis that growing endothelial cells on one side of an ultra-thin, highly porous membrane and differentiating astrocyte or astrogliomal cells on the opposite side will lead to a higher degree of interaction between the two cell types and therefore to an improved model. Here we describe our initial efforts towards testing this hypothesis including a procedure for membrane fabrication and methods for culturing endothelial cells on these membranes. We have fabricated a 1 $\mu\textrm{m}$ thick, 2.0 $\mu\textrm{m}$ pore size, and 55% porous membrane with a very narrow pore size distribution from low-stress silicon nitride (SiN) utilizing techniques from the microelectronics industry. We have developed a base, acid, autoclave routine that prepares the membranes for cell culture both by cleaning residual fabrication chemicals from the surface and by increasing the hydrophilicity of the membranes (confirmed by contact angle measurements). Gelatin, fibronectin, and a 50/50 mixture of the two proteins were evaluated as potential basement membrane protein treatments prior to membrane cell seeding. All three treatments support adequate attachment and growth on the membranes compared to the control.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.165-172
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• 1999

In the present work , the transport mechanism of a capsaicin derivative, DA-5018, through blood-brain barrier (BBB) has been investigated to evaluate the feasibility of potential drug development. The result of pharmacokinetic parameters obtained from the intravenous injection of plasma volume marker,$[3^H]RSA$ and $[{14}^C]DA-5018$, indicated that both AUC, area under the plasma concentration curve and VD, volume of distribution in brain of $[3^H]RSA$ agreed with those reported ($1620{\pm}10 $percentage injected dose minute per milliliter (%IDmin/ml) and $12.0{\pm}0.1{\mu}l/g$, respectively). Elimination half-life and AUC of $[{14}^C]DA-5018$is corrected by the PHLC analysis, 19.6$\pm$1.2 min and 7.69$\pm$0.85% IDmin/ml, respectively. The metabolic rate of $[{14}^C]DA-5018$was very rapid. The blood-brain barrier permeability surface area (PS) product of $[{14}^C]DA-5018$ was calculated to be 0.24$\pm$0.05 $\mu$l/min/g. The result of internal carotid artery perfusion and capillary depletion suggested that [14C]DA-5018 pass through BBB with the time increasingly. Investigation of transport mechanism of $[{14}^C]DA-5018$ using agonist and antagonist suggested that vanilloid (capsaicin) receptor did not exist in the BBB, and nutrient carrier system in the BBB has no effect on the transport of DA-5018. In conclusion, despite the fact that penetration of DA-5018 through BBB is significant, the intact drug found in the brain tissue is small because of a rapid metabolism. Therefore, for the central analgesic effect of DA-5018, the method to increase the metabolic stability in plasma and the brain permeability should be considered.

• Archives of Pharmacal Research
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• v.28 no.4
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• pp.443-450
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• 2005

In the present study, we have characterized the choline transport system and examined the influence of various amine drugs on the choline transporter using a conditionally immortalized rat brain capillary endothelial cell line (TR-BBB) in vitro. The cell-to-medium (C/M) ratio of $[^3{H}]choline$ in TR-BBB cells increased time-dependently. The initial uptake rate of $[^3{H}]choline$ was concentration-dependent with a Michaelis-Menten value, $K_{m}$, of $26.2\pm2.7{\mu}M$. The $[^3{H}]choline$ uptake into TR-BBB was $Na^{+}-independent$, but was membrane potential-dependent. The $[^3{H}]choline$ uptake was susceptible to inhibition by hemicholinium-3, and tetraethy-lammonium (TEA), which are organic cation transporter substrates. Also, the uptake of $[^3{H}]choline$ was competitively inhibited with $K_{i}$ values of $274 {\mu}M, 251 {\mu}M and 180 {\mu}M$ in the presence of donepezil hydrochloride, tacrine and $\alpha-phenyl-n-tert-butyl nitrone$ (PBN), respectively. These characteristics of choline transport are consistent with those of the organic cation transporter (OCT). OCT2 mRNA was expressed in TR-BBB cells, while the expression of OCT3 or choline transporter (CHT) was not detected. Accordingly, these results suggest that OCT2 is a candidate for choline transport at the BBB and may influence the BBB permeability of amine drugs.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.20 no.1 s.32
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• pp.99-114
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• 2007

Objectives : Atopic dermatitis has a close relationship with damage of skin barrier function. To investigate the effects of Bangpungtongsungsan(BT) extract to the skin damage on mice model after atopic dermatitis elicitation, this study was done through forcing injury to mice's skin. Methods : The BALB/c mice were distributed into three groups: control(CON) group, atopic dermatitis(AD)-elicited group, Bangpungtongsungsan(BT)-treated group. AD-elicited and BT-treated group were caused AD according to the method of Christophers E., Mrowietz and Minehiro. The BT extract was administered for 48 hours to BT-treated group. We observed changes of external dermal formation, eosinophils in vasculature, lipid formation in stratum corneum, distribution of ceramide, distribution of capillary, $I{\kappa}B$ kinase(IKK) and induce nitric oxide synthase(iNOS) mRNA expression. We used the statistical methods of student t-test(p<0.05). Results : After dispensing BT extract into the AD-elicited group, the number of eosinophil as an atopic index in mice noticeably decreased and dermal injury decreased. Also the decrease of hyperplasia, degranulated mast cells, angiogenesis and substance P were shown. The lipid lamellae, lipid protect formation, were repaired and the distribution of ceramide which inhibit protein kinase C(PKC) activation increased, and the PKC caused inhibition of nuclear $factor(NF)-{\kappa}B$ activation. As a result of inhibition of $NF-{\kappa}B$ activation, iNOS production were inhibited and apoptotic cell were increased. Moreover the decrease of IKK and iNOS mRNA expression in BT-treated RAW 264.7 cell were noted. Conclusion : BT mitigated skin damage on mice model after atopic dermatitis elicitation through recovering skin barrier function and inhibiting nuclear $factor(NF)-{\kappa}B$ activation.

• Biomolecules & Therapeutics
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• v.27 no.3
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• pp.290-301
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• 2019

Paeonol has neuroprotective function, which could be useful for improving central nervous system disorder. The purpose of this study was to characterize the functional mechanism involved in brain transport of paeonol through blood-brain barrier (BBB). Brain transport of paeonol was characterized by internal carotid artery perfusion (ICAP), carotid artery single injection technique (brain uptake index, BUI) and intravenous (IV) injection technique in vivo. The transport mechanism of paeonol was examined using conditionally immortalized rat brain capillary endothelial cell line (TR-BBB) as an in vitro model of BBB. Brain volume of distribution (VD) of [$^3H$]paeonol in rat brain was about 6-fold higher than that of [$^{14}C$]sucrose, the vascular space marker of BBB. The uptake of [$^3H$]paeonol was concentration-dependent. Brain volume of distribution of paeonol and BUI as in vivo and inhibition of analog as in vitro studies presented significant reduction effect in the presence of unlabeled lipophilic compounds such as paeonol, imperatorin, diphenhydramine, pyrilamine, tramadol and ALC during the uptake of [$^3H$]paeonol. In addition, the uptake significantly decreased and increased at the acidic and alkaline pH in both extracellular and intracellular study, respectively. In the presence of metabolic inhibitor, the uptake reduced significantly but not affected by sodium free or membrane potential disruption. Similarly, paeonol uptake was not affected on OCTN2 or rPMAT siRNA transfection BBB cells. Interestingly. Paeonol is actively transported from the blood to brain across the BBB by a carrier mediated transporter system.

• Economic and Environmental Geology
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• v.56 no.2
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• pp.167-183
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• 2023

Gases originated from the final SNF (spent nuclear fuel) disposal site are very mobile in the barrier and they may also affect the migration of radioactive nuclides generated from the SNF. Mechanisms of gas-nuclide migration in the multi-barrier and their influences on the safety of the disposal site should be understood before the construction of the final SNF disposal site. However, researches related to gas-nuclide coupled movement in the multi-barrier medium have been very little both at home and abroad. In this study, properties of gas generation and migration in the SNF disposal environment were reviewed through previous researches and their main mechanisms were summarized on the hydrogeological evolution stage of the SNF disposal site. Gas generation in the SNF disposal site was categorized into five origins such as the continuous nuclear fission of the SNS, the Cu-canister corrosion, the oxidation-reduction reaction, the microbial activity, and the inflow from the natural barriers. Migration scenarios of gas in porous medium of the multi-barrier in the SNF repository site were investigated through reviews for previous studies and several gas migration types including ① the free gas phase flow including visco-capillary two-phase flow, ② the advection and diffusion of dissolved gas in pore water, ③ dilatant two-phase flow, and ④ tensile fracture flow, were presented. Reviewed results in this study can support information to design the further research for the gas-nuclide migration in the repository site and to evaluate the safety of the Korean SNF disposal site in view points of gas migration in the multi-barrier.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1521_1522
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• 2009

Chemotaxis is the directed movement of cells in gradients of signaling molecules, an essential biological process that underlies morhpogenesis during development, and the recruitment of immune cells to sites of infection. Especially, bacterial chemotaxis has utilized as an important prelude to study metabolism, prey-predator relationship, symbiosis, other ecological interactions in microbial communities. Recently, novel analytical formats integrated with microfluidics were introduced to investigate the chemotaxis of the cells with the precise control of chemical gradient and small volume of cells. In this study, we present a method to detect bacterial chemotaxis by direct fluidic contacting. The developed fluidic-handling method is driven by capillary force, hydrophobic barrier and a cohesion force between fluids. We have investigated the chemotactic response of E Coli. and Pseudomonas aeruginosa to three kinds of chemoeffectors such as HEPES buffer, peptone and chloroform.