• 대한기계학회논문집A
• /
• 제33권7호
• /
• pp.629-636
• /
• 2009

Mechanical stimulation is known to play a vital role on the differentiation of mesenchymal stem cells (MSCs) to pre-osteoblasts. In this research, we developed a tensile cell stimulator, composed of a DC motor-driven actuator and LVDT sensor for measuring linear displacement, to study the effects of tensile stress on osteogenic differentiation of MSCs. First, we demonstrated the reliability of this device by showing the uniform strain field in the silicon substrate. Secondly, we investigated the effects of tensile stretching on osteogenic differentiation. We imposed a pre-set cyclic strain at a fixed frequency on cell monolayer cultured on a flexible silicon substrate while varying its amplitude and duration. 60 min of resting period was allowed between 30 min of cyclic stretching and this cycle is repeated up to 7 days. Under the combined stimulation with osteogenic media and mechanical stretching, the osteogenic markers such as alkaline phosphatase (ALP), osterix, and osteopontin began to get expressed as early as 4 days of stimulation, which is much shorter than what is typically required for osteogenic media induced differentiation. Moreover, different markers were induced at different magnitudes of the applied strains. Lastly, for the case of ALP, we observed the antagonistic effects of osteogenic media when combined with mechanical stretching.

• 대한임상검사과학회지
• /
• 제38권2호
• /
• pp.141-146
• /
• 2006

Vagal nerve stimulation (VNS) has been proposed as a possible way to improve the control of refractory epilepsy. We report the effects following VNS treatment in patients with refractory epilepsy. Seventeen patients with a mean age of 12.8 years, ranging from 5 to 29 years, underwent the implantation of vagal nerve stimulation (Cyberonics, Houston, TX). We reviewed the clinical findings before and after VNS in seizure frequency, number of antiepileptic drugs (AED), and quality of life (QOL). All of the patients had intractable seizures, eleven of the patients had additional medical complications, three had hippocampus atrophy, one had encephalomalacia, five had encephalitis, one had pachygyria, and one had schizencephaly. Thirteen patients had symptomatic partial epilepsies, three patients had Lennox-Gastaut syndrome and one had cryptogenic partial epilepsy. The mean follow up duration was 35 months. The mean reduction of seizure frequency compared with baseline before VNS was 26.1% after 3 months (p<0.005), 41.9% after 6 months (p<0.001), 46.9% after 1 year (p<0.001), and 53% at the latest follow-up (p<0.001). Twelve patients showed an improvement of QOL such as mood, language, alertness, expression, and motor function. The most common side effects were transient hoarseness or voice change or cough, which was detected in six patients (35%) and wound infection in one patient (5%). This study has shown a good anti-seizure effect of VNS, decrease in seizure frequency and improvements in QOL. We concluded that VNS is a beneficial therapy in refractory epilepsy with a non-resectable epileptic focus. Further studies should be focused on the prediction of unresponsiveness and the adjustment of VNS parameters for maximum efficacy in patients with various medical histories.

• Journal of Korean Neurosurgical Society
• /
• 제65권2호
• /
• pp.276-286
• /
• 2022

Objective : Spinal cord stimulation (SCS) is an effective treatment for chronic neuropathic pain. However, its clinical efficacy in regard to specific types of pain has not been well studied. The primary objective of this study was to retrospectively analyze the clinical outcomes of paddle-type SCS according to the type of neuropathic pain. Methods : Seventeen patients who underwent paddle-lead SCS at our hospital were examined. Clinical outcomes were evaluated pre- and postoperatively (3 months, 1 year, and last follow-up) using the Neuropathic Pain Symptom Inventory (NPSI). The NPSI categorizes pain as superficial, deep, paroxysmal, evoked, or dysesthesia and assess the duration of the pain (pain time score). Changes in NPSI scores were compared with change in Visual analogue scale (VAS) scores. Results : After SCS, the pain time score improved by 45% (independent t-test, p=0.0002) and the deep pain score improved by 58% (independent t-test, p=0.001). Improvements in the pain time score significantly correlated with improvements in the VAS score (r=0.667, p=0.003, Spearman correlation). Additionally, the morphine milligram equivalent value was markedly lower after vs. before surgery (~49 mg, pared t-test, p=0.002). No preoperative value was associated with clinical outcome. Conclusion : The NPSI is a useful tool for evaluating the therapeutic effects of SCS. Chronic use of a paddle-type spinal cord stimulation improved the deep pain and the pain time scores.

• 대한정형도수물리치료학회지
• /
• 제26권1호
• /
• pp.65-72
• /
• 2020

Background: The purpose of this research is to investigate the effects of joint mobilization and transcutaneous electrical nerve stimulation (TENS) on pain threshold and hormonal changes in patients with chronic LBP. Methods: 14 patients with chronic LBP were divided into the experimental group and the control group with 7 patients each, and both groups of patients were evaluated on pain duration, blood tests, and pressure pain threshold (PPT) on their first visit. On their second visit, joint mobilization was applied to the experimental group for 10 min and TENS to the control group for 20 min. Results: Pain threshold and duration of analgesia increased from after treatment in the experimental group. Serotonin and Cortisol decreased after treatment in the experimental group. Conclusion: Joint mobilization in patients with chronic LBP caused an increase in pain duration and pain thresholds and a decrease in serotonin, whereas there was little difference in cortisol.

• 동의생리병리학회지
• /
• 제18권1호
• /
• pp.226-229
• /
• 2004

We investigated the comparative effect with different frequency and duration time of electroacupuncture(EA) for suppression of pain. Inflammation was induced by an intraplantar injection of 1 % carrageenan into the right hind paw. Bilateral EA stimulation with 2 Hz, 15 Hz and 120 Hz were delivered at those acupoints corresponding to Zusanli and Sanyinjiao in man via the needles in carrageenan-injected rats. The paw and tail thermal hyperalgesia were measured in 30-minute intervals after carrageenan injection using hot plate and tail flick analgesia meter, respectively. The significant difference was found between the control and any of EA frequencies examined. Especially 2 Hz EA presented more effective inhibitory effects compared with other frequency of EA in tail flick latency. The hyperalgesia induced by carrageenan was strongly inhibited by 2 Hz EA from 5 min post and reached sufficient effects from 20 min post EA treatment. These results suggest that EA treatment might be a useful therapy for mitigation of inflammatory pain.

• Clinical and Experimental Reproductive Medicine
• /
• 제44권4호
• /
• pp.232-238
• /
• 2017

Objective: To determine whether reducing the cetrorelix dose in the antagonist protocol to 0.125 mg had any deleterious effects on follicular development, the number and quality of retrieved oocytes, or the number of embryos, and to characterize its effects on the affordability of assisted reproductive technology. Methods: This randomized controlled study was conducted at the Fertility Unit of Tanta Educational Hospital of Tanta University, the Egyptian Consultants' Fertility Center, and the Qurrat Aien Fertility Center, from January 1 to June 30, 2017. Patients' demographic data, stimulation protocol, costs, pregnancy rate, and complications were recorded. Patients were randomly allocated into two groups: group I (n = 61) received 0.125 mg of cetrorelix (the study group), and group II (n = 62) received 0.25 mg of cetrorelix (the control group). Results: The demographic data were comparable regarding age, parity, duration of infertility, and body mass index. The dose of recombinant follicle-stimulating hormone units required was $2,350.43{\pm}150.76$ IU in group I and $2,366.25{\pm}140.34$ IU in group II, which was not a significant difference (p= 0.548). The duration of stimulation, number of retrieved oocytes, and number of developed embryos were not significantly different between the groups. The clinical and ongoing pregnancy rates likewise did not significantly differ. The cost of intracytoplasmic sperm injection per cycle was significantly lower in group I than in group II (US $ $494.66{\pm}4.079$ vs. US $ $649.677{\pm}43.637$). Conclusion: Reduction of the cetrorelix dose in the antagonist protocol was not associated with any significant difference either in the number of oocytes retrieved or in the pregnancy rate. Moreover, it was more economically feasible for patients in a low-resource country.

• 대한의용생체공학회:의공학회지
• /
• 제28권2호
• /
• pp.212-217
• /
• 2007

As a preliminary study for the development of electrical stimulation strategy of artificial retina, we set up a method fur the reconstruction of input intensity variation from retinal ganglion cell(RGC) responses. In order to estimate light intensity variation, we used an optimal linear filter trained from given stimulus intensity variation and multiple single unit spike trains from RGCs. By applying ON/OFF stimulation(ON duration: 2 sec, OFF duration: 5 sec) repetitively, we identified three functional types of ganglion cells according to when they respond to the ON/OFF stimulus actively: ON cell, OFF cell, and ON-OFF cell. Experiments were also performed using a Gaussian random stimulus and a binary random stimulus. The input intensity was updated once every 90 msec(i. e. 11 Hz) to present the stimulus. The result of reconstructing 11 Hz Gaussian and binary random stimulus was not satisfactory and showed low correlation between the original and reconstructed stimulus. In the case of ON/OFF stimulus in which temporal variation is slow, successful reconstruction was achieved and the correlation coefficient was as high as 0.8.

• 한국수정란이식학회지
• /
• 제8권2호
• /
• pp.151-157
• /
• 1993

The present study was undertaken to determine the optimal condition for parthenogenetic activation of rabbit oocytes by electric stimulation in vitro in an attempt to develop nuclear transplantation techniques for cloning mammalian embryos and animals. Freshly ovulated oocytes were collected from superovulated rabbits from 13 to 26 hrs. after hCG injection. The cumulus-free oocytes were activated parthenogetically by repeated stimuli of square direct electric pulses in O.3M mannitol solution. After applying electric stimulations of different voltages, pulse durations and pulse times, all of the oocytes were cultured in TCM-199 with 10% FCS for 96 hours in a 5% $CO_2$ incubator, and their developmental potential in vitro was examined. The higher activation rate (68.9%) was achieved at the voltage of 2.0kv/cm, the pulse duration of 60 $\mu$sec and three pulse times and the activation rate of 100% was achieved at the pulse duration of 100 and 200 $\mu$sec, the voltage of 1.5kv/cm and three pulse times. Although the higher rates of activation of oocytes were achieved at 100 and 200 $\mu$sec, none of them developed to blastocyst in vitro. The oocytes collected 18~20 hours post hCG injection showed the highest rate of activation and development to blastocyst in vitro than the oocytes collected 13~15 or 25~26 hours post hCG injection. Therefore, it can be suggested that the application of electric stimulation of 2.0kv/cm, 60 $\mu$sec and three pulse times to the oocytes collected at 18~20 hours post hCG injection would be more beneficial for the parthenogenetic activation of oocytes in rabbits.

• Journal of Magnetics
• /
• 제15권4호
• /
• pp.213-220
• /
• 2010

Since the hypothalamus immediately reacts to a nerve by processing all the information from the human body and the external stimulus being conducted, it performs a significant role in internal secretion; thus, a diverse and rapid stimulus pulse is required. By detecting Zero Detector accurately via the application of AVR on-Chip (ATMEL) using commercial electricity, chopping generates a stimulus pulse to the brain using an IGBT gate to designate a new magnetic stimulation following treatment and diagnosis. To simplify and generate a diverse range of stimuli for the brain, chopping can be used as a free magnetic stimulator. Then, commercial frequency (60Hz) is chopped precisely at the first level of the leakage transformer to deliver an appropriate stimulus pulse towards the hypothalamus when necessary. Discharge becomes stable, and the chopping frequency and duty-ratio provide variety after authorizing a high-pressure chopping voltage at the second level of the magnetic stimulator. These methods have several aims. The first is to apply a variable stimulus pulse via accurate switching frequency control by a voltaic pulse or a pulse repetition rate, according to the diagnostic purpose for a given hypothalamus. Consequently, the efficiency tends to increase. This experiment was conducted at a maximum of 210 W, a magnetic induced amplitude of 0.1~2.5 Tesla, a pulse duration of $200{\sim}350\;{\mu}s$, magnetic inducement of 5 Hz, stimulus frequency of 0.1~60 Hz, and a duration of stimulus train of 1~10 sec.

• Journal of Acupuncture Research
• /
• 제17권2호
• /
• pp.221-230
• /
• 2000

This study was undertaken to determine effect of Zusan1i(ST36) acupuncture (AP) on the small intestinal motility in the rabbit. Changes in the motility in vivo of ileum was measured before and 20 min. after AP. In order to examine whether AP effect was affected by autonomic nerves, norepinephrine or acetylcholine was applicated. AP significantly increased the mean wave amplitude and motor index, but not the mean wave duration and motor activity. Infusion of norepinephrine ($2{\mu}m$) into an ear vein resulted in a decrease in the mean wave amplitude and motor index, which was not affected by AP. Acetylcholine ($10{\mu}m$) produced inhibition followed by stimulation of motility. The stimulation of motility was induced by an increase in the mean wave amplitude and motor index, but not the mean wave duration and motor activity. The effect of acetylcholine was not significantly different between before and after AP. These results suggest that Zusan1i(ST36) acupuncture stimulates the small intestinal motility, which is not mediated by autonomic nerves. Therefore, Zusan1i(ST36) acupuncture seems to be applicable to impaired small intestinal movement.