• The Korean Journal of Physiology and Pharmacology
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• v.17 no.2
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• pp.121-125
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• 2013

The purpose of this study is to investigate the antinociceptive effects of ginsenosides on toothache. c-Fos immunoreactive (IR) neurons were examined after noxious intrapulpal stimulation (NS) by intrapulpal injection of 2 M KCl into upper and lower incisor pulps exposed by bone cutter in Sprague Dawley rats. The number of Fos-IR neurons was increased in the trigeminal subnucleus caudalis (Vc) and the transitional region between Vc and subnucleus interpolaris (Vi) by NS to tooth. The intradental NS raised arterial blood pressure (BP) and heart rate (HR). The number of Fos-IR neurons was also enhanced in thalamic ventral posteromedial nucleus (VPMN) and centrolateral nucleus (CLN) by NS to tooth. The intradental NS increased the number of Fos-IR neurons in the nucleus tractus solitarius (NTS) and rostral ventrolateral medulla (RVLM), hypothalamic supraoptic nucleus (SON) and paraventricular nucleus (PVN), central cardiovascular regulation centers. Ginsenosides reduced the number of c-Fos-IR increased by NS to tooth in the trigeminal Vc and thalamic VPMN and CLN. Naloxone, an opioid antagonist, did not block the effect of ginsenoside on the number of Fos-IR neurons enhanced by NS to tooth in the trigeminal Vc and thalamic VPMN and CLN. Ginsenosides ameliorated arterial BP and HR raised by NS to tooth and reduced the number of Fos-IR neurons increased by NS to tooth in the NTS, RVLM, hypothalamic SON, and PVN. These results suggest that ginsenosides have an antinociceptive effect on toothache through non-opioid system and attenuates BP and HR increased by NS to tooth.

• Experimental and Molecular Medicine
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• v.50 no.11
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• pp.2.1-2.16
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• 2018

Supplementation of mesenchymal stem cells (MSCs) at sites of bone resorption is required for bone homeostasis because of the non-proliferation and short lifespan properties of the osteoblasts. Calcium ions ($Ca^{2+}$) are released from the bone surfaces during osteoclast-mediated bone resorption. However, how elevated extracellular $Ca^{2+}$ concentrations would alter MSCs behavior in the proximal sites of bone resorption is largely unknown. In this study, we investigated the effect of extracellular $Ca^{2+}$ on MSCs phenotype depending on $Ca^{2+}$ concentrations. We found that the elevated extracellular $Ca^{2+}$ promoted cell proliferation and matrix mineralization of MSCs. In addition, MSCs induced the expression and secretion of osteopontin (OPN), which enhanced MSCs migration under the elevated extracellular $Ca^{2+}$ conditions. We developed in vitro osteoclast-mediated bone resorption conditions using mouse calvaria bone slices and demonstrated $Ca^{2+}$ is released from bone resorption surfaces. We also showed that the MSCs phenotype, including cell proliferation and migration, changed when the cells were treated with a bone resorption-conditioned medium. These findings suggest that the dynamic changes in $Ca^{2+}$ concentrations in the microenvironments of bone remodeling surfaces modulate MSCs phenotype and thereby contribute to bone regeneration.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.1
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• pp.25-32
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• 2014

Nitric oxide (NO) is recognized as a mediator and regulator of inflammatory responses. NO is produced by nitric oxide synthase (NOS), and NOS is abundantly expressed in the human dental pulp cells (HDPCs). NO produced by NOS can be cytotoxic at higher concentrations to HDPCs. However, the mechanism by which this cytotoxic pathway is activated in cells exposed to NO is not known. The purpose of this study was to elucidate the NO-induced cytotoxic mechanism in HDPCs. Sodium nitroprusside (SNP), a NO donor, reduced the viability of HDPCs in a dose- and time-dependent manner. We investigated the in vitro effects of nitric oxide on apoptosis of cultured HDPCs. Cells showed typical apoptotic morphology after exposure to SNP. Besides, the number of Annexin V positive cells was increased among the SNP-treated HDPCs. SNP enhanced the production of reactive oxygen species (ROS), and N-acetylcysteine (NAC) ameliorated the decrement of cell viability induced by SNP. However, a soluble guanylate cyclase inhibitor (ODQ) did not inhibited the decrement of cell viability induced by SNP. SNP increased cytochrome c release from the mitochondria to the cytosol and the ratio of Bax/Bcl-2 expression levels. Moreover, SNP-treated HDPCs elevated activities of caspase-3 and caspase-9. While pretreatment with inhibitors of caspase (z-VAD-fmk, z-DEVD-fmk) reversed the NO-induced apoptosis of HDPCs. From these results, it can be suggested that NO induces apoptosis of HDPCs through the mitochondria-dependent pathway mediated by ROS and Bcl-2 family, but not by the cyclic GMP pathway.

• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.501-511
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• 2009

This study was conducted to develop self-healing ability of concrete so that inspection could be available even in the event of minute cracks without complex works at any time for more economic concrete structure maintenance and longevity. A completely different method has been carried out in comparison with many of similar researches on self-healing concrete. This is a basic study on the development of self-healing concrete using microbial biomineralization. Compounds were generated except for cells by precipitation reaction of CaC$O_3$ during the microbial metabolism and we examined the use as a binder that hardens the surface of sand using biomineralization that Sporosarcina pasteurii precipitates CaC$O_3$. In result, the formation of new mineral and hardening of sand surface could be verified partly, and it was available for cracks to be repaired by calcite with organic (microorganism) and inorganic (CaC$O_3$) complex structure through the basic experiment a little bit. Therefore the use of biomineralization by this sort of microbial metabolism for concrete structure helps to develop absolute repair-concrete like this concrete with microorganism. The effect of microbial application will be one of the most important research tasks having influence on not only repair for concrete structure but also development of new materials able to reduce environmental problems.

• The Korean Journal of Malacology
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• v.26 no.1
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• pp.1-18
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• 2010

Biological organisms produce organic-inorganic nanocomposite composites that are hierarchically organized in composition and microstructure, containing both inorganic and organic components in complicated mixtures. The process related to the generation and regeneration of organic-inorganic complex in nature is called biomineralization process. Understanding how the process operates in a biological environment is a valuable guide to the synthesis of novel advanced material and developing important industrial processes. Like the mechanism of organisms, mollusks were also synthesized from interaction between organic matrices and minerals and their morphology was designed through biomineralization. In this study, shell formation has been studied as a bio-model and the application of biomimetics based on biomineralization is focused.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1311-1322
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• 2021

Microbially induced calcium carbonate precipitation (MICP) has recently become an intelligent and environmentally friendly method for repairing cracks in concrete. To improve on this ability of microbial materials concrete repair, we applied random mutagenesis and optimization of mineralization conditions to improve the quantity and crystal form of microbially precipitated calcium carbonate. Sporosarcina pasteurii ATCC 11859 was used as the starting strain to obtain the mutant with high urease activity by atmospheric and room temperature plasma (ARTP) mutagenesis. Next, we investigated the optimal biomineralization conditions and precipitation crystal form using Plackett-Burman experimental design and response surface methodology (RSM). Biomineralization with 0.73 mol/l calcium chloride, 45 g/l urea, reaction temperature of 45℃, and reaction time of 22 h, significantly increased the amount of precipitated calcium carbonate, which was deposited in the form of calcite crystals. Finally, the repair of concrete using the optimized biomineralization process was evaluated. A comparison of water absorption and adhesion of concrete specimens before and after repairs showed that concrete cracks and surface defects could be efficiently repaired. This study provides a new method to engineer biocementing material for concrete repair.

• International Journal of Oral Biology
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• v.38 no.1
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• pp.13-19
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• 2013

Various voltage-gated $K^+$ currents were recently described in dorsal root ganglion (DRG) neurons. However, the characterization and diversity of voltage-gated $K^+$ currents have not been well studied in trigeminal root ganglion (TRG) neurons, which are similar to the DRG neurons in terms of physiological roles and anatomy. This study was aimed to investigate the characteristics and diversity of voltage-gated $K^+$ currents in acutely isolated TRG neurons of rat using whole cell patch clamp techniques. The first type (type I) had a rapid, transient outward current ($I_A$) with the largest current size having a slow inactivation rate and a sustained delayed rectifier outward current ($I_K$) that was small in size having a fast inactivation rate. The $I_A$ currents of this type were mostly blocked by TEA and 4-AP, K channel blockers whereas the $I_K$ current was inhibited by TEA but not by 4-AP. The second type had a large $I_A$ current with a slow inactivation rate and a medium size-sustained delayed $I_K$ current with a slow inactivation rate. In this second type (type II), the sensitivities of the $I_A$ or $I_K$ current by TEA and 4-AP were similar to those of the type I. The third type (type III) had a medium sized $I_A$ current with a fast inactivation rate and a large sustained $I_K$ current with the slow inactivation rate. In type III current, TEA decreased both $I_A$ and $I_K$ but 4-AP only blocked $I_A$ current. The fourth type (type IV) had a smallest $I_A$ with a fast inactivation rate and a large $I_K$ current with a slow inactivation rate. TEA or 4-AP similarly decreased the $I_A$ but the $I_K$ was only blocked by 4-AP. These findings suggest that at least four different voltage-gated $K^+$ currents in biophysical and pharmacological properties exist in the TRG neurons of rats.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.155-161
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• 2017

Teeth and bones are highly mineralized tissues containing inorganic minerals such as calcium phosphate, and a growing number of evidences show that their mineral content is associated with many diseases. Although the quantification of mineral contents by micro-computed tomography(micro- CT) has been used in diagnosis and evaluation for treating bone diseases, its application for teeth diseases has not been well established. In this study, we attempted to estimate a usefulness of a high-resolution micro-CT in analysis of human teeth. The teeth were scanned by using the Skyscan 1172 micro-CT. In order to measure tooth mineral content, beam hardening effect of the machine was corrected with a radiopaque iodine-containing substance, iodoacetamide. Under the maximum resolution of $6.6{\mu}m$, X-ray densities in teeth and hydroxyapatite standards were obtained with Hounsfield unit (HU), and they were then converted to an absolute mineral concentration by a CT Analyzer software. In enamel layer of cusp area, the mean mineral concentration was about $2.14mg/mm^3$ and there was a constant mineral concentration gradient from the enamel surface to the dentinoenamel junction. In the dentin of middle 1/3 of tooth, the mean mineral concentration was approximately $1.27mg/mm^3$ and there was a constant mineral concentration gradient from the outer of root to the pulp side, ranging from 1.3 to $1.06mg/mm^3$. In decay region of dentin, the mineral content was gradually decreased from the intact inner side to the decayed surface. These results suggest that high-resolution micro-CT can be as a useful tool for non-invasive measurement of mineral concentration in teeth.

• ALGAE
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• v.27 no.2
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• pp.135-137
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• 2012

The stalks of the eustigmatophyte $Pseudocharaciopsis$ $minuta$ were examined by light and scanning electron microscopy. Light microscopy revealed orange-red granules at the base of the stalk. Energy dispersive X-ray microanalysis of the bases indicated that they were mainly composed of manganese. Manganese has not been previously reported from eustigmatophytes. This study indicates that the Eustigmatophyceae needs further study into many aspects of the biology.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.350-354
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• 2010

In natural world various inorganic crystals are grown with controlled shape and size in hybrid forms with organics. Such natural processes have been attempted much to mimick artificially. One of the example is calcium carbonate which has been examined a lot in the field of biomineralization. In this study, we utilize well-organized surface of polydiacetylene(PDA) films as the crystal-growing template. We devised a novel mini-arrayer device that transfers PDA films at air/water interfaces of each array well and deposit them to hydrophobized glass substrates. This technical improvement will contribute to facilitate better understandings of biomineralization mechanism.