• The Journal of Korean Academy of Prosthodontics
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• v.18 no.1
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• pp.37-47
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• 1980

The purpose of this study was to investigate the stresses in different proximal margins and to measure, quantitatively, the effect of different modifications in the design of preparations on the stresses using two-dimensional photoelasticity. Photoelastic stress analysis is based on the phenomenon, exhibited by most transparent solids, of becoming birefringent, or doubly refracting, when strained. Two birefringent materials were used in this study, PSM-1 and PSM-5 in .standard sheet ($10'{\times}10'{\times}\frac{1}{4}'$ thickness), PSM-1(polyester) was used for constructing the substructure, and PSM-5(epoxy resin) was used in making the restorations to be investigated. Two birefringent materials were used in the construction of composite photoelastic model. Seven variable models were constructed. The peripheral dimensions of all model were constant and the models represent an occlusomesial section of a lower posterior molar. Model 1 represents the knife edge margin (shoulderless), Model 2 represents the chamfer, Model 3 represents a rounded shoulder(no sharp angle between the axial wall and gingival floor), Model 4 represents a flat shoulder (axial wall is a $90^{\circ}$ angle to the gingival wall), Model 5 represents $+15^{\circ}$ angulation, Model 6 has a $-15^{\circ}$ angulation, and Model 7 is the same as Model 4 except that it has a $45^{\circ}$ bevel. Improved artificial stone was used to represent dental cement in luting the composite photoelastic model. Static loading procedures(100 pounds) were used at preplanned sites. The results were as follows; 1. The stresses in the proximal portion of all tested models were compressive in nature when the proximal shoulders were loaded vertically on the same proximal marginal ridge. 2. The round and chamfered preparations were the optimum designs in proximoocclusal restorations. They showed the lowest stress concentration factor, i.e. 2.16 and 2.23, respectively. The knife edged shoulder had the highest value, K=5.39. Round type shoulder geometry experiments reduced the stress concentration factor (S.C.F.) 3. The gingival portion of proximal shoulder geometry was a critical location for stress concentration.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1518-1524
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• 2008

Ponciri Fructus (PF), the immature fruit of Poncirus trifoliata, has been used for treatment of constipation in Korean traditional medicine. It has been reported that PF has a prokinetic effect on gastrointestinal tract, but little is known about the effect on colonic contraction. The aim of this study was to investigate the effect of PF on spontaneous contractions of proximal and distal colon in rats. The aqueous extract of PF was centrifuged and filtered and its supernatant was used for in vitro motility study. The removed colon from rats was divided into proximal and distal segments. Each segment was mounted in a 10 ml organ bath and measured the change of the spontaneous contraction with increasing dose (1, 5, 10, 50, 100, 500, $1000{\mu}g/ml$) of PF extract administration. Also the effect of PF on the spontaneous contraction was measured under treatment of atropine, acetylcholine (Ach), and tetrodotoxin (TTX). PF increased the spontaneous phasic contraction of distal colon dose dependently, but there was no change in proximal colon. The contractile response induced by PF in distal colon was lower than that of Ach and was partially blocked by atropine ($10^{-6}M$). TTX increased the spontaneous contraction and it was reinforced with Ach addition. But the extract of PF had no or little contractile effect of TTX in colon. PF increased spontaneous contractions selectively in distal colon. The prokinetic effect of PF may be due to enhancement of cholinergic related excitatory neural system.

• The Korean Journal of Pharmacology
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• v.29 no.1
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• pp.73-83
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• 1993

In order to examine the effect of ${\beta}-estradiol$ on the cell growth, using a primary rabbit kidney poximal tubule cell culture system. We investigated the effect of ${\beta}-estradiol$ on alpha 1 (IV) collagen and ${\beta}-actin$ mRNA levels from primary rabbit kidney cell cultures, and also the effects of 3 growth factors and ${\beta}-estradiol$ supplementation on the growth of primary rabbit kidney proximal tubule cells in the serum-free medium. 1 nM of ${\beta}-estradiol$ showed a sizable potentiation effect on the growth of the proximal tubule cell in serum-free medium, but higher concentration (> 10 nM) of estradiol indeed inhibited the growth. In the absence of hydrocortisone as a growth supplement in serum-free medium, ${\beta}-estradiol$ caused to potentiate the growth of the cell. In the presence of hydrocortisone, ${\beta}-estradiol$ also potentiated the growth of the proximal tubule cells. According to the Northern analysis, ${\beta}-estradiol$ increased the level of ${\beta}-actin$ mRNA, although mRNA level of the alpha I(IV) collagen was not changed significantly.

• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.473-482
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• 2012

Purpose: The purpose of this study was to investigate the stress distribution of the surrounding tissues according to 3 proximal plate types of the RPI clasp. Methods: The removeable partial denture which mandibular right and left second premolars and mandibular molars were lost was attached to a three dimensional photo elastic epoxy resin model. Then 120N of vertical load was applied. After 3-dimensional photoelastic stress analysis was used to record the isochromatic fringe patterns. Results: Kratochvil type guiding plane exhibited little uniform stress distribution on load center and alveolar ridge, but higher stress concentration on buccal surface of second premolar. Krol type guiding plane exhibited the stress concentration on the front of load center and relatively higher stress concentration on buccal surface of first premolar. However, this type had no effect on canine. Researcher type guiding plane showed the stress concentration on second premolar and molar, but the little stress distribution on first premolar. Conclusion: In all types, excessive stress concentration was appeared and three types were not significant different.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.3
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• pp.187-191
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• 2003

$Na^+/H^+$ exchanger (NHE) has a critical role in regulation of intracellular pH (pHi) in the renal proximal tubular cells. It has recently been shown that dopamine inhibits NHE in the renal proximal tubules. Nevertheless, there is a dearth of information on the effects of long-term (chronic) dopamine treatment on NHE activities. This study was performed to elucidate the pHi regulatory mechanisms during the chronic dopamine treatments in renal proximal tubular OK cells. The resting pHi was greatly decreased by chronic dopamine treatments. The initial rate and the amplitude of intracellular acidification by isosmotical $Na^+$ removal from the bath medium in chronically dopamine-treated cells were much smaller than those in control. Although it seemed to be attenuated in $Na^+$-dependent pH regulation system, $Na^+$-dependent pHi recovery by NHE after intracelluar acid loading in the dopamine-treated groups was not significantly different from the control. The result is interpreted to be due to the balance between the stimulation effects of lower pHi on the NHE activity and counterbalance by dopamine. Our data strongly suggested that chronic dopamine treatment increased intrinsic intracellular buffer capacity, since higher buffer capacity was induced by lower resting pHi and this effect could attenuate pHi changes under extracellular $Na^+$-free conditions in chronically dopamine-treated cells. Our study also demonstrated that intracellular acidification induced by chronic dopamine treatments was not mediated by changes in NHE activity.

• The Journal of Korean Physical Therapy
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• v.29 no.2
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• pp.95-100
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• 2017

Purpose: This study aimed to evaluate the changes in dorsiflexion and balance following proximal and distal tibiofibular joint manipulation in individuals with a history of lateral ankle sprain (LAS). Methods: Fifteen participants with a history of unilateral LAS, exhibiting a restriction in ankle dorsiflexion were included in this study. LAS ankle received a manipulation to the proximal and distal tibiofibular joint, while the opposite control ankle received no manipulation intervention. The outcome measures included ankle dorsiflexion and balance. Ankle dorsiflexion was measured using weight-bearing lunge test. Static and dynamic balances were measured using the overall, anterioposterior, and mediolateral balance index via the biodex balance system. Measurements were obtained prior to and following manipulation. Results: This study showed that ankle dorsiflexion and dynamic balance were improved following the manipulation compared to those prior to the manipulation (p<0.05). There was no significant change in static balance (p>0.05). Conclusion: The joint manipulation technique applied to the ankle of those with a history of LAS appears to improve ankle dorsiflexion and dynamic balance. This suggest that a manipulation to the proximal and distal tibiofibular joint could be provided as preliminary data regarding the prophylactic effects of recurrent LAS.

• Journal of Korean Medicine Rehabilitation
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• v.31 no.2
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• pp.109-114
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• 2021

The purpose of this study is to report the effect in treating a patient with a case of avulsion fracture of the proximal 5th metatarsal with a combination of Korean medicine therapy. We treated the patient with acupuncture, pharmacopuncture, moxibustion, cupping, and herbal medicine The numeric rating scale, X-ray were applied as outcome measures. After complex Korean medicine treatment, this patient's avulsion fracture of the proximal 5th metatarsal was improved and pain was reduced. This result shows that Korean medical therapy may be an effective option for avulsion fracture of the proximal 5th metatarsal.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.191-202
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• 1995

The purpose of this study was to compare effects of insulin and IGFs on growth, apical membrane enzyme activities and membrane transport systems of primary cultured rabbit kidney proximal tubule cells. Results were as follows: 1. Insulin and IGF-I produced significant growth stimulatory effects at $5{\times}10^{-10}M.\;IGF-II(5×10^{-10}\;M)$ did not stimulate significant cell growth. 2. Insulin stimulated the phosphorylation of a 97 KD protein. It was difficult to determine whether this band represents insulin and/or the IGF-I receptor. 3. The activities of apical membrane enzymes (alkaline phosphatase, leucine aminopeptidase, and ${\gamma}-glutamyl \;transpeptidase)$ were observed to be diminished after the cells were placed in the culture environment. 4. The uptake of ${\alpha}-MG,$ Pi and Na was significantly increased in cells incubated with insulin or IGF-I, IGF-II had no effect on the uptake of these substrates. 5. Na-pump activity, as assayed by Rb uptake, was significantly increased in cells treated with insulin or IGFs. In conclusion, insulin and IGF-I exert stimulatory effects on growth and membrane transporter(glucose, Na, Pi, and Na-pump) activities in primary cultured rabbit kidney proximal tubule cells. IGF-II had no effect on cell growth and membrane transporter(glucose, Na and Pi) activities.

• The Korean Journal of Physiology
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• v.25 no.2
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• pp.171-177
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• 1991

This study was carried out to determine effect of acute renal ischemia on transport function of organic cation, tetraethylammonium (TEA), in rabbit kidney proximal tubule. Clamping of the renal artery for 30 and 60 min produced a polyuria which was accompanied by an increase in $Na^+$ excretion. The capacity of kidney cortical slices to accumulate TEA was increased after 30 and 60 min of ischemia. When blood flow was restored for 30 min after 30 and 60 min of ischemia, the augmented TEA uptake was recovered to the control values. Oxygen consumption of cortical slices was stimulated after 30 min of ischemia, whereas it was not altered by 60 min of ischemia. A 90-min ischemia produced a significant inhibition of TEA uptake and tissue oxygen consumption. These results suggest that the basolateral transport system for organic cation persists after ischemic periods of 60 min despite evidence that tubular reabsorptive mechanism of $Na^+$ and water is markedly impaired. This may indicate that the active secretory systems of proximal tubule are more resistant to ischemic injury than the reabsorptive systems.

• Journal of Korean Neurosurgical Society
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• v.53 no.3
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• pp.150-154
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• 2013

Objective : To evaluate the effect of electromagnetic (EM) navigation system on ventriculoperitoneal (VP) shunt failure rate through comparing the result of standard shunt placement. Methods : All patients undergoing VP shunt from October 2007 to September 2010 were included in this retrospective study. The first group received shunt surgery using EM navigation. The second group had catheters inserted using manual method with anatomical landmark. The relationship between proximal catheter position and shunt revision rate was evaluated using postoperative computed tomography by a 3-point scale. 1) Grade I; optimal position free-floating in cerebrospinal fluid, 2) Grade II; touching choroid or ventricular wall, 3) Grade III; tip within parenchyma. Results : A total of 72 patients were participated, 27 with EM navigated shunts and 45 with standard shunts. Grade I was found in 25 patients from group 1 and 32 patients from group 2. Only 2 patients without use of navigation belonged to grade III. Proximal obstruction took place 7% in grade I, 15% in grade II and 100% in grade III. Shunt revision occurred in 11% of group 1 and 31% of group 2. Compared in terms of proximal catheter position, there was growing trend of revision rate according to increase of grade on each group. Although infection rate was similar between both groups, the result had no statistical meaning (p=0.905, chi-square test). Conclusion : The use of EM navigation in routine shunt surgery can eliminate poor shunt placement resulting in a dramatic reduction in failure rates.