• The Korean Journal of Physiology and Pharmacology
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• 제27권6호
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• pp.541-553
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• 2023

Retinal prostheses have shown some clinical success in restoring vision in patients with retinitis pigmentosa. However, the post-implantation visual acuity does not exceed that of legal blindness. The reason for the poor visual acuity might be that (1) degenerate retinal ganglion cells (RGCs) are less responsive to electrical stimulation than normal RGCs, and (2) electrically-evoked RGC spikes show a more widespread not focal response. The single-biphasic pulse electrical stimulation, commonly used in artificial vision, has limitations in addressing these issues. In this study, we propose the benefit of multiple consecutive-biphasic pulse stimulation. We used C57BL/6J mice and C3H/HeJ (rd1) mice for the normal retina and retinal degeneration model. An 8 × 8 multi-electrode array was used to record electrically-evoked RGC spikes. We compared RGC responses when increasing the amplitude of a single biphasic pulse versus increasing the number of consecutive biphasic pulses at the same stimulus charge. Increasing the amplitude of a single biphasic pulse induced more RGC spike firing while the spatial resolution of RGC populations decreased. For multiple consecutive-biphasic pulse stimulation, RGC firing increased as the number of pulses increased, and the spatial resolution of RGC populations was well preserved even up to 5 pulses. Multiple consecutive-biphasic pulse stimulation using two or three pulses in degenerate retinas induced as much RGC spike firing as in normal retinas. These findings suggest that the newly proposed multiple consecutive-biphasic pulse stimulation can improve the visual acuity in prosthesis-implanted patients.

• Journal of Plant Biotechnology
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• 제38권1호
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• pp.22-29
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• 2011

비생물학적 스트레스로 $H_2O_2$를 이용하여 산화적 스트레스와 고염분 스트레스를 처리한 후 ROS의 생성을 확인한 결과 스트레스 처리 후 30분에 일시적으로 1차 peak를 형성하였다가 거의 basal level까지 감소하고 다시 증가하여 3시간에 매우 다량의 2차 peak를 형성한 후 거의 basal level로 다시 낮아지는 biphasic 양상을 나타내게 된다. 따라서 ROS의 생성은 초기 30분 내에 일시적으로 발생한 Phase I의 ROS와 Phase II의 좀 더 장기적으로 다량의 고농도로 발생된 ROS의 생리적 역할이 다를 것으로 여겨진다. 본 논문에서는 스트레스 처리 시 생성되는 ROS를 확인한 후 ROS 생성 유전자인 RbohD와 RbohF 유전자 발현이 억제된 RbohD-AS, RbohF-AS 형질전환 식물체를 이용하여 실험을 수행하였다. 스트레스에 의해 생성되는 ROS의 생성을 억제시킴으로써 스트레스에 대한 ethylene 생성이 더 적은 것으로 나타났다. 또한, 이들 형질전환 식물체에서 ethylene 생성과 $H_2O_2$ 억제 효과를 확인하였으며 고염분 등의 스트레스에 대한 저항성은 ROS와 ethylene의 생성이 저하되어 나타난 것으로 판단된다. 산화적 스트레스와 고염분 스트레스에서 후기 ethylene이 다량으로 생성되는 시기, 즉 세포손상이 초래되는 후기에서 DNA fragmentation 분석을 통해서 ROS와 ethylene의 생성이 높은 식물체일수록 PCD가 높게 나타난 것으로 여겨지며, 이 과정에서 작용하는 유전자는 RbohD와 RbohF인 것으로 보이며, RbohD가 더 효과적으로 작용하는 것으로 생각된다. 따라서 스트레스에 반응하는 신호전달과정에서 초기에 ROS가 생성이 되고 후기에 ethylene이 다량으로 생성되어 결국 세포죽음에 이르게 하는 상호 synergism을 일으켜 반응을 나타내며, 이러한 반응 과정에서 RbohD와 RbohF 유전자 발현의 억제가 스트레스에 대한 식물체의 저항성을 높이는 것으로 사료된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.293-296
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• 2002

Hyperosmotic pressure increased specific antibody productivity ($q_{Ab}$) of recombinant CHO cells (SH2-0.32) while it depressed cell growth. Thus, the use of hyperosmolar medium did not increase the maximum antibody concentration substantially. To overcome this drawback, the feasibility of biphasic culture strategy was investigated. In the biphasic culture, cells were first cultivated in the standard medium with physiological osmolality(294 mOsm/kg) for cell growth. When cells reached the late exponential phase of growth, the spent standard medium was replaced with the fresh hyperosmolar medium (522 mOsm/kg) for antibody production. The ($q_{Ab}$) in growth phase with the standard medium was 2.1 ${\mu}g/10^6cell/day$ while the ($q_{Ab}$) in antibody production phase with the hyperosmolar medium (522 mOsm/kg) was 11.1 ${\mu}g/10^6cell/day$. Northern blot analysis showed a positive relationship between the relative contenet of Ig mRNA and ($q_{Ab}$), indicating that transcriptional regulation was involved in the response of rCHO cells to hyperosmotic pressure. Due to the enhanced ($q_{Ab}$) and increased cell concentration in biphasic culture, the maximum antibody concentration obtained in biphasic culture with 522 mOsm/kg medium exchange was 161% higher than that obtained in batch culture with the standard medium. Taken together, simple biphasic culture strategy based on hyperosmotic culture for improved foreign protein production from rCHO cells is effective in improving antibody production of rCHO cells.

• 대한수의학회지
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• 제61권2호
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• pp.14.1-14.7
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• 2021

Biosilica is a silica-based substance derived from the cell walls (frustules) of diatoms. Recently, research into biosilica's biological functions is underway, but little has been reported on the effects of biosilica on immune cells. In this study, we investigated the effect of ionized biosilica water (iBW) on dendritic cells (DCs), which play crucial roles as antigen (Ag)-presenting cells. Treatment with iBW increased the expression of immune response-related markers, closely connected to the maturation of DCs, and the production of tumor necrosis factor-alpha. In addition, iBW-treated DCs (iBW-DCs) had a lower uptake of fluorescein isothiocyanate-dextran than that of control DCs. Mixed leukocyte response analysis used for measuring the Ag-presenting capability of DCs, showed iBW-DCs had a higher capability than that of control DCs. Interestingly, DCs treated with lipopolysaccharide (LPS) and iBW had a lower level of Ag-presenting capability than that of LPS-treated DCs. Taken together, the results indicate that iBW alone can mature DCs, but it decreases the Ag-presenting capability of DCs in the presence of LPS, a representative agent of inflammation. This study may provide valuable information regarding the effect of iBW on immune cells. Further research is needed to investigate how iBW induces the observed biphasic immunomodulatory activity.

• 한국식품영양학회지
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• 제10권2호
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• pp.151-159
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• 1997

근원섬유단백질의 이온강도에 따른 Ca-ATPase 활성, Mg-ATPase 활성 및 EDTA-ATPase 활성은 오징어와 대합에서 그 차이점이 뚜렷하였으며, activity-pH curve에서 오징어 actomyosin의 Ca-ATPase 활성은 biphasic response가 소실되었고 대합의 actomyosin은 미약한 bipasic response가 나타났다. 또한 저농도의 dioxane에 의하여 오징어의 근원섬유단백질은 급격한 활성의 감소를 보였으나 대합의 근원섬유단백질은 활성이 증가되었다. 그리고 에탄올과 메탄올은 오징어와 대합의 myosin 및 MM에 대하여 저농도에서 활성을 증가시켰다. 한편 NEM으로 근원섬유단백질을 modification시키며 10-6M 이하의 NEM 농도에서는 활성이 증가되었으나 10-5M 이상의 농도가 되면 활성의 급격한 감소가 나타났다.

• 대한물리의학회지
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• 제6권2호
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• pp.207-213
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• 2011

Purpose: The purpose of this study was to determine the preventive effect of joint mobilization on biphasic pain response induced formalin test. Methods: Sprague-dawley rats(n=30) were ramdomly divided into the control group without intervention, sham control group with application of hand contact without mobilization, joint mobilization group with application of hand contact with mobilization. Joint mobilization of knee procedure involved an grade III extension mobilization basically with anterior-posterior gliding of the tibia on the femur. Formalin injection caused biphasic pain response which is lated for 60 minute. The first phase result from primary afferent sensory fiber, wheareas the second phase has been proposed to central sensitization in the central nervous system. Behavioral analysis was performed by digital camera after 5% formalin subcutaneous injection into the dorsal foot. Results: Pain response of joint mobilization group show significant lower than control gorup and sham control group. Conclusion: This result suggest that pre-application of joint mobilization may be effective intervention to prevent the formalin induced pain.

• The Korean Journal of Physiology
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• 제29권2호
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• pp.203-216
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• 1995

The effects of ${\alpha}_1-adrenergic$ receptor stimulation on membrane potential, intracellular $Na^+$ activity, and twitch force were investigated in ventricular muscles from guinea-pig hearts. Action potentials, intracellular $Na^+$ activity, and twitch force of ventricular papillary muscles were measured simultaneously under various experimental conditions. Stimulation of the ${\alpha}_1-adrenergic$ receptor by phenylephrine produced variable changes in action potential duration, a slight hyperpolarization of the diastolic membrane potential, a decrease in intracellular $Na^+$ activity, and a biphasic inotropic response in which a transient negative inotropic response was followed by a sustained positive inotropic response. These changes were blocked by prazosin, an antagonist of the ${\alpha}_1-adrenergic$ receptor, but not by atenolol, an antagonist of the ${\beta}-adrenergic$ receptor. This indicates that the changes in membrane potential, intracellular $Na^+$ activity, and twitch force are mediated by stimulation of the ${\alpha}_1-adrenergic$ receptor, but not by stimulation of ${\beta}-adrenergic$ receptor. The decrease in intracellular $Na^+$ activity was not observed in quiescent muscles, depending on the rate of the action pontentials in beating muscles. The intracellular $Na^+$ activity decrease was substantially inhibited by tetrodotoxin. However, the decrease in intracellular $Na^+$ activity was not affected by an inhibition of the $Na^+-K^+$ pump. Therefore, the decrease in intracellular $Na^+$ activity mediated by the ${\alpha}_1-adrenergic$ receptor appears to be due to a reduction of $Na^+$ influx during the action potential, perhaps through tetrodotoxin sensitive $Na^+$ channels. Our study also revealed that the decrease in intracellular $Na^+$ activity might be related to the transient negative inotropic response. The intracellular $Na^+$ activity decrease could lower intracellular $Ca^{2+}$ through the $Na^+-Ca^{2+}$ exchanger and thereby produce a decline in twitch force.

• The Korean Journal of Physiology
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• 제25권2호
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• pp.201-209
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• 1991

The rostral ventrolateral medulla (RVLM) has been established recently as a sympathoexcitatory area. The present study was conducted to investigate whether the somatosympathetic pressor and/or depressor responses are mediated through RVLM in cats anesthetized with ${\alpha}-chloralose$. An occipital craniectomy was performed and ventrolateral medulla were stimulated either electrically or chemically to evoke changes in arterial blood pressure. And then the effect of lesions in the ventrolateral medulla on the changes in blood pressure elicited by the peripheral nerve stimulation was observed. Followings are the results obtained: 1) Pressor areas were found in the ventrolateral medulla, lateral reticular nucleus and rostral dorsal area. 2) Depressor areas were found mainly in the ventrolateral medulla rostral to the pressor areas. 3) Some areas showed biphasic responses: a depressor response to lower frequency and a pressor response to higher frequency stimulation. 4) After electrical lesion in pressor area in RVLM, the somatosympathetic pressor response was abolished or depressed markedly. The somatosympathetic depressor response, however, remained after the lesion. 5) Electrical lesion in the depressor area abolished somatosympathetic depressor response. From the above results it is concluded that somatosympathetic pressor response is mediated through RVLM, while somatosympathetic depressor response is not mediated through RVLM.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.108-108
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• 1997

The effects of nalbuphine.HCI on the spontaneous locomotor activity and primary humoral immune response were investigated in ICR mice. Nalbuphine was intraperitoneally administered with the dose of 130, 260, 360 mg/kg in mice. The locomotor activity such as distance traveled was observed for 90min at 10min intervals. Nalbuphine showed the biphasic dose-response relationship on the spontaneous locomotor activity. IgM plaque forming cells(PFC) in splenocytes and IgM level in antiserum were significantly decreased depending on the dose of nalbuphine when nalbuphine was administered after the immunization, but slightly increased only at the low dose in the case of nabuphine administration after the immunization(SRBC).

• Archives of Pharmacal Research
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• 제21권4호
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• pp.370-373
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• 1998

Ten substituted phenacyl derivatives of 4-hydroxypiperidine were synthesized and studied for their effects on the mean arterial blood pressure (MABP) in normotensive anaesthetized rats and smooth muscles contractions of isolated rabbit jejunum. Two derivatives caused fall in blood pressure at the dose of 10-20 mg/kg and one rise in blood pressure at the dose of 20 mg/kg. Two compounds exhibited biphasic response (hypotensive followed by hypertensive) and one gave triphasic response at 10 mg/kg dose. Rest of four derivatives were found devoid of any effect on mean arterial blood pressure up to the dose of 30 mg/kg. All the derivatives except two caused relaxant effect on the spontaneous contraction of rabbit jejunum at the dose range of 0.1 -2 mg/kg.