• Title/Summary/Keyword: 무작위성

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EFFECT OF ULTRASONIC VIBRATION ON ENAMEL AND DENTIN BOND STRENGTH AND RESIN INFILTRATION IN ALL-IN-ONE ADHESIVE SYSTEMS (All-in-one 접착제에서 초음파진동이 법랑질과 상아질의 결합강도와 레진침투에 미치는 영향)

  • Lee, Bum-Eui;Jang, Ki-Taeg;Lee, Sang-Hoon;Kim, Chong-Chul;Hahn, Se-Hyun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.1
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    • pp.66-78
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    • 2004
  • The objective of this study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration in enamel and dentin achieved with those gained using the conventional technique and vibration technique. For enamel specimens, thirty teeth were sectioned mesio-distally. Sectioned two parts were assigned to same adhesive system but different treatment(vibration vs. non-vibration). Each specimen was embedded in 1-inch inner diameter PVC pipe with a acrylic resin. The buccal and lingual surfaces were placed so that the tooth and the embedding medium were at the same level. The samples were subsequently polished silicon carbide abrasive papers. Each adhesive system was applied according to its manufacture's instruction. Vibration groups were additionally vibrated for 15 seconds before curing. For dentin specimen, except removing the coronal part and placing occlusal surface at the mold level, the remaining procedures were same as enamel specimen. Resin composite(Z250. 3M. U.S.A.) was condensed on to the prepared surface in two increments using a mold kit(Ultradent Inc., U.S.A.). Each increments was light cured for 40 seconds. After 24 hours in tap water at room temperature, the specimens were thermocycled for 1000cycles. Shear bond strengths were measured with a universal testing machine(Instron 4465, England). To investigate infiltration patterns of adhesive materials, the surface of specimens was examined with scanning electron microscope. The results were as follows: 1. In enamel the mean values of shear bond strengths in vibration groups(group 2, 4, 6) were greater than those of non-vibration group(group 1, 3, 5). The differences were statistically significant except AQ bond group. 2. In dentin, the mean values of shear bond strengths in vibration groups(group 2, 4, 6) were greater than those of non-vibration groups(group 1, 3, 5). But the differences were not statistically significant except One-Up Bond F group. 3. The vibration group showed more mineral loss in enamel and longer resin tag and greater number of lateral branches in dentin under SEM examination.

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Utilization of Song-Gang Stone as the Dietary Additve in Juvenile Olive Flounder, Paralichthys olivacus (치어기 넙치에 있어서 사료 첨가제로서 송강약돌의 이용 가능성)

  • 최세민;고수홍;박건준;임성률;유광열;이제희;배승철
    • Journal of Aquaculture
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    • v.17 no.1
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    • pp.39-45
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    • 2004
  • Three experiments were conducted to determine utilization of Song-Gang(equation omitted) stone as the dietary additive for growth and immune stimulant in juvenile olive flounder. In the feeding trial, four diets were formulated to contain 0, 0.5, 1.0 and 2.0% Song-Gang(equation omitted) stone per kg diet (SGS$_{0}$ , SGS$_{0.5}$, SGS$_{1.0}$ , SGS$_{2.0}$ ). Fish averaging 5.0$\pm$0.04 g (mean$\pm$SD) were fed one of four experimental diets in triplicate groups for 8 weeks. There were no significant differences in weight gain, feed efficiency, protein efficiency ratio, hematosomatic index, condition factor and survival among fish fed all the diets. In chanlenge test, fish were infected by intraperitoneal injection of 0.1 $m\ell$ bacterial suspension with Edwardsielia tarda per fish after the feeding trial. Fish fed SGS$_{0.5}$ diet have a significantly higher cumulative survival rate than did fish fed the other diets (P<0.05). In the anti-mold test, Asprrgiilus niger, Penicillium pinophiltfm, Chaeromium globosum were inoculated with Song-Gang(equation omitted) stone using ASTM G-21 method. The amount of Α. niger, Ρ. pinuphiium. C. globosum didn't increase in Song-Gang(equation omitted) stone for 4 weeks for the test period. Therefore, these results indicate that 0.5% Song-Gang(equation omitted) stone per kg diet could increase immune resistance in juvenile olive flounder and Song-Gang(equation omitted) stone could be used as the anti-mold additive in fish feed.

Clinical Significance of Low-colony Count Scotochromogen Nontuberculous Mycobacteria (균집락수가 적은 암색소성 비결핵항산균 배양의 임상적 의미)

  • Lee, Jung Yeon;Kim, Mi-Na;Chung, Hee-Jung;Jun, Kyung Ran;Choi, Hee Jin;Lee, Hyeyoung;Joung, Eun Young;Oh, Yeon-Mok;Lee, Sang Do;Kim, Woo Sung;Kim, Dong Soon;Kim, Won Dong;Shim, Tae Sun
    • Tuberculosis and Respiratory Diseases
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    • v.59 no.1
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    • pp.39-46
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    • 2005
  • Background : Even though it has been suggested that low-colony, scotochromogen nontuberculous mycobacteria (NTM) are usually contaminants and not true pathogens, evidence for this hypothesis has not been provided. This study investigated the colony characteristics, organism identification, and clinical significance of low-colony scotochromogen. Methods : The laboratory cultured 6,898 respiratory clinical specimens for an examination of mycobacteria over a three-month period. A low-colony count was arbitrarily defined as ${\leq}20$ colonies. This study analyzed the recovery rate of the mycobacteria, the number of colonies and their gross characteristics, and their clinical significance. PCR-restriction fragment length polymorphism analysis was carried out to identify the NTM species. NTM pulmonary disease was defined according to the American Thoracic Society. Results : A total of 6,898 respiratory specimens for mycobacterium were cultured. Of these, 263 (3.8%) grew NTM, and 382 (5.5%) grew M. tuberculosis. Of the 263 cultured NTM specimens, 124 (47.1%) were scotochromogens. The smear-positive rate was significantly lower in these scotochromogens (4.8%) than in the non-scotochromogens (23.7%) (p<0.05). The most common isolates were M. gordonae (83/102, 81.4%) in the scotochromogens, and MAC (52/121, 43.0%) in the non-scotochromogens. Even though three out of 113 patients with a low-colony scotochromogen has been diagnosed with NTM pulmonary disease, the isolated scotochromogen was not considered to be the cause of the NTM disease but was just a contaminant. Conclusion : In this study, the most common isolate of a low-colony count scotochromogen was M. gordonae, which appeared to be contaminants and not true pathogens. Greater efforts in the quality control of a mycobacterium laboratory are needed in cases where there is a high recovery rate of low-colony count scotochromogen.

Measuring the Third-Person Effects of Public Opinion Polls: Focusing On Online Polls (여론조사보도에 대한 제3자효과 검증: 온라인 여론조사를 주목하며)

  • Kim, Sung-Tae;Willnat, Las;Weaver, David
    • Korean journal of communication and information
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    • v.32
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    • pp.49-73
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    • 2006
  • During the past decades, public opinion polls have become an ubiquitous tool for probing the complexity of people's beliefs and attitudes on a wide variety of issues. Especially since the late 1970s, the use of polls by news organizations has increased dramatically. Along with the proliferation of traditional polls, in the past few years pollsters and news organizations have come to recognize the advantages of online polls. Increasingly there has been more effort to take the pulse of the public through the Internet. With the Internet's rapid growth during the past years, advocates of online polling often emphasize the relative advantages over traditional polls. Researchers from Harris Black International Ltd., for example, argue that "Internet polling is less expensive and faster and offers higher response rates than telephone surveys." Moreover, since many of the newer online polls draw respondents from large databases of registered Internet users, results of online polls have become more balanced. A series of Harris Black online polls conducted during the 1998 gubernatorial and senatorial elections, for example, has accurately projected the winners in 21 of the 22 races it tracked. Many researchers, however, severely criticize online polls for not being representative of the larger population. Despite the often enormous number of participants, Internet users who participate in online polls tend to be younger, better educated and more affluent than the general population. As Traugott pointed out, the people polled in Internet surveys are a "self selected" group, and thus "have volunteered to be part of the test sample, which could mean they are more comfortable with technology, more informed about news and events ... than Americans who aren't online." The fact that users of online polls are self selected and demographically very different from Americans who have no access to the Internet is likely to influence the estimates of what the majority of people think about social or political issues. One of the goals of this study is therefore to analyze whether people perceive traditional and online public opinion polls differently. While most people might not differentiate sufficiently between traditional random sample polls and non representative online polls, some audiences might perceive online polls as more useful and representative. Since most online polls allow some form of direct participation, mostly in the form of an instant vote by mouse click, and often present their findings based on huge numbers of respondents, consumers of these polls might perceive them as more accurate, representative or reliable than traditional random sample polls. If that is true, perceptions of public opinion in society could be significantly distorted for those who rely on or participate in online polls. In addition to investigating how people perceive random sample and online polls, this study focuses on the perceived impact of public opinion polls. Similar to these past studies, which focused on how public opinion polls can influence the perception of mass opinion, this study will analyze how people perceive the effects of polls on themselves and other people. This interest springs from prior studies of the "third person effect," which have found that people often tend to perceive that persuasive communications exert a stronger influence on others than on themselves. While most studies concerned with the political effects of public opinion polls show that exit polls and early reporting of election returns have only weak or no effects on the outcome of election campaigns, some empirical findings suggest that exposure to polls can move people's opinions both toward and away from perceived majority opinion. Thus, if people indeed believe that polls influence others more than themselves, perceptions of majority opinion could be significantly altered because people might anticipate that others will react more strongly to poll results.

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THE EFFECT OF REBONDING IN MICROLEAKAGE OF CLASS V RESTORATIONS UNDER LOAD CYCLING (부하순환 하에서 제V급 복합레진 수복물의 미세변연누출에 대한 재접착제의 효과에 관한 연구)

  • Youn, Yeon-Hee;Kim, Young-Jae;Kim, Jung-Wook;Jang, Ki-Taeg;Lee, Sang-Hoon;Kim, Chong-Chul;Hahn, Se-Hyun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.3
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    • pp.527-533
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    • 2004
  • One clinical technique recommended for improving marginal integrity is "rebonding" or application of unfilled resins to the surface of composite restoration. But continuously the restorations are affected with occlusal load. There is room for doubt that the rebonding agent has the positive effect on microleakage in spite of the stress generated by the occlusal load. This study determined the effect of rebonding on microleakage of Class V resin composite restorations under load cycling. Class V cavities were prepared on the buccal surface of 40 sound extracted premolars and restored with a hybrid light-cured resin composite according to manufacturers' directions. They were randomly divided into two groups consisting of 20 samples: a control(group I), without surface sealing, and the other group(group II) in which margins were etched and rebonded. After thermocycling, each of groups was divided into subgroups(group A, B), and load cycling(total 100,000 cycles with 4-100N load at a rate of 1 Hz) were applied on the group B. Assessment of microleakage utilized methylene blue dye penetration. The following results were obtained: 1. In the occlusal region, no significant difference was noted in the scores regardless of whether or not the rebonding agent was used(group TA-IIA, IB-IIB)(p>0.05). 2. In the cervical region, the control group with rebonding(group IIA) showed the better result than the group without rebonding(group IA)(p<0.05). 3. In the cervical region, the rebonded group with load cycling(group IIB) showed similar results to the group without rebonding(group IB) and no significant difference was noted(p>0.05).

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Changes of Sputum Matrix Metalloproteinases and Tissue Inhibitor of Matrix Metalloproteinase-1 by Antibiotic Treatment in Acute Exacerbation of Chronic Bronchitis (만성 기관지염의 급성 악화에서 항생제 투여에 의한 유도객담 내 Matrix metalloproteinase와 Tissue inhibitor of matrix metalloproteinase의 변화)

  • Yoon, Hyoung-Kyu;Ahn, Joong-Hyun;Kim, Chi-Hong;Kwon, Soon-Seog;Kim, Young-Kyoon;Kim, Kwan-Hyung;Moon, Hwa-Sik;Park, Sung-Hak;Song, Jeong-Sup
    • Tuberculosis and Respiratory Diseases
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    • v.53 no.4
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    • pp.420-430
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    • 2002
  • Background : Excessive extracellular matrix (ECM) deposition by airway inflammation is presumed to play an important role in the pathogenesis of worsening airflow obstruction (Ed- acceptable three-word noun) seen during acute exacerbations of chronic bronchitis. Although many proteases can cleave ECM molecules, matrix metalloproteinases (MMPs) and their inhibitors are likely to be the physiologically relevant mediators of ECM degradation. Objectives ; The purpose of this study was to demonstrate that antibiotic treatment can change airway MMPs and TIMP-1 concentrations/levels by controlling airway inflammation in acute exacerbation of chronic bronchitis. Methods : We studied 40 patients, all of whom had an acute exacerbation of chronic bronchitis. The patients were treated with two different antibiotics, moxifloxacin and clarithromycin, in a double-blind manner for 7 days. Sputum samples were induced and collected before and after antibiotic therapy. We measured the sputum concentration of MMP-1,-9, TIMP-1, IL-8 and secretory leukocyte proteinase inhibitor (SLPI) in sputum supernatants by ELISA method. Results : There was no difference after antibiotic treatment in the sputum concentrations of MMP-1,-9, TIMP-1, IL-8 and SLPI between the patients treated with moxifloxacin and those treated with clarithromycin. But the sputum concentrations of TIMP-1, and SLPI, and the TIMP-1/MMP-1 ratio were significantly reduced by the antibiotic therapy. There were significant positive correlations between sputum TIMP-1 levels and IL-8 levels (p<0.01, r=0.751), and between the sputum TIMP-1/MMP-1 ratio and IL-8 levels (p<0.01, r=0.752). The sputum SLPI levels were significantly elevated by antibiotic treatment and were negatively correlated with sputum TIMP-1 levels (p<0.01, r=-0.496) and TIMP-1/MMP-1 levels (p<0.01, r=-0.456). Conclusion : The study shows that the worsening of airway inflammation in acute exacerbation of chronic bronchitis is associated with an imbalance between the concentrations/levels of TIMP-1 and MMPs. Antibiotic treatment can prevent progression of airway narrowing in acute exacerbation of chronic bronchitis by modulation of the protease and anti-protease imbalance.

Efficacy of Low-dose Hydrocortisone Infusion for Patients with Severe Community-acquired Pneumonia Who Invasive Mechanical Ventilation (기계 환기가 요구된 중증 지역사회 획득 폐렴에서 저용량 하이드로코르티손 주입의 효과)

  • Kim, Ho Cheol;Lee, Seung Jun;Ham, Hyoun Seok;Cho, Yu Ji;Jeong, Yi Yeong;Lee, Jong Deok;Hwang, Young Sil
    • Tuberculosis and Respiratory Diseases
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    • v.60 no.4
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    • pp.419-425
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    • 2006
  • Background : Severe community-acquired pneumonia (CAP) can develop into respiratory failure that requires mechanical ventilation (MV), which is associated with a higher rate of mortality. It was recently reported that a hydrocortisone infusion in severe CAP patients was associated with a significant reduction in the length of the hospital stay and mortality. This study evaluated efficacy of a hydrocortisone infusion for patients with severe CAP requiring MV. Methods : From February 2005 to July 2005, 13 patients (M : F = 10 : 3, mean age: $68.6{\pm}14.1years$), who were diagnosed with severe CAP and required MV, were enrolled in this study. Hydrocortisone was administered as an intravenous 200mg loading bolus, which was followed by an infusion at a rate of 10mg/hour for 7 days. The control group was comprised of patients with severe CAP requiring MV but in whom corticosteroid was not used before study period. The clinical and physiologic parameters on or by day 8 and the outcome in the hydrocortisone infusion group were compared with those in the control group. Results : 1) There was no significant difference in age, gender ratio, SAPS II, SOFA score, temperature, leukocyte count, PaO2/FiO2 (P/F) ratio, the number of patients with P/F ratio < 200, chest radiograph score, lung injury score and catecholamine-dependent septic shock between the hydrocortisone infusion group and control group at day 1. 2) At day 8, the proportion of patients with an improvement in the P/F ratio ${\geq}100$ and the chest radiograph score was significantly higher in the hydrocortisone infusion group than in the control group (61.5% vs. 15.4%, 76.9% vs. 23.1%, p< 0.05). However, there was no significant difference in the other clinical and physiologic parameters. 3). There was no significant difference in the duration of the MV, ICU stay, hospital stay and 10th and 30th day mortality between the two groups. Conclusion : Hydrocortisone infusion for patients with severe CAP requiring invasive mechanical ventilation may be effective in improving the level of oxygenation and the chest radiograph score.

Ex vivo Morphometric Analysis of Coronary Stent using Micro-Computed Tomography (미세단층촬영기법을 이용한 관상동맥 스텐트의 동물 모델 분석)

  • Bae, In-Ho;Koh, Jeong-Tae;Lim, Kyung-Seob;Park, Dae-Sung;Kim, Jong-Min;Jeong, Myung-Ho
    • Journal of the Korean Society of Radiology
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    • v.6 no.2
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    • pp.93-98
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    • 2012
  • Micro-computed tomography (microCT) is an important tool for preclinical vascular imaging, with micron-level resolution. This non-destructive means of imaging allows for rapid collection of 2D and 3D reconstructions to visualize specimens prior to destructive analysis such as pathological analysis. Objectives. The aim of this study was to suggest a method for ex vivo, postmortem examination of stented arterial segments with microCT. And ex vivo evaluation of stents such as bare metal or drug eluting stents on in-stent restenosis (ISR) in rabbit model was performed. The bare metal stent (BMS) and drug eluting stent (DES, paclitaxel) were implanted in the left or right iliac arteries alternatively in eight New Zealand white rabbits. After 4 weeks of post-implantation, the part of iliac arteries surrounding the stent were removed carefully and processed for microCT. Prior to microCT analysis, a contrast medium was loaded to lumen of stents. All samples were subjected to an X-ray source operating at 50 kV and 200 ${\mu}A$ by using a 3D isotropic resolution. The region of interest was traced and measured by CTAN analytical software. Objects being exposed to radiation had different Hounsfield unit each other with values of approximately 1.2 at stent area, 0.12 ~ 0.17 at a contrast medium and 0 ~ 0.06 at outer area of stent. Based on above, further analyses were performed. As a result, the difference of lengths and volumes between expanded stents, which may relate to injury score in pathological analysis, was not different significantly. Moreover, ISR area of BMS was 1.6 times higher than that of DES, indicating that paclitaxel has inhibitory effect on cell proliferation and prevent infiltration of restenosis into lumen of stent. And ISR area of BMS was higher ($1.52{\pm}0.48mm^2$) than that of DES ($0.94{\pm}0.42mm^2$), indicating that paclitaxel has inhibitory effect on cell proliferation and prevent infiltration of restenosis into lumen of stent. Though it was not statistically significant, it showed that the extent of neointema of mid-region of stents was relatively higher than that of anterior and posterior region in parts of BMS as showing cross-sectional 2-D image. suggest that microCT can be utilized as an accessorial tool for pathological analysis.

A Telephone Survey on the Opinions about Family Doctor (주치의에 대한 인식도 전화 조사)

  • Seo, Hong-Gwan;Kang, Jae-Heon;Kim, Cheol-Hwan;Kim, Seong-Won
    • Journal of Preventive Medicine and Public Health
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    • v.31 no.2 s.61
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    • pp.310-322
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    • 1998
  • In order to reinforce the role of primary care physician and o improve doctor-patient relationship, the Korean government tried to introduce 'Family Doctor Registration Program' into Seocho-Gu in Seoul, Ansung-Gun and Paju city in Kyunggi-Do in Oct. 1996. Community residents and doctors in those area did not show much interest in this project because of low incentives. We have done this study to see how much people know 'Family Doctor Registration Program' and what is people's real needs about 'Family Doctor Registration Program'. We selected 1,800 telephone numbers in Seoul, Chongju city, and Ansung-Gun by multi-stage stratified random sampling. Three trained survey personnels called them and got answers to the premade questionnaire until they completed the questionnaires of 200 persons in each community. The calling time was 7-9 p.m. from Monday to Friday, 3-9 p.m. on Saturday, and 9 a.m. to 9 p.m. on Sunday. We dropped out the persons who did not respond 3 times. The subjects consisted of 222 male and 367 female residents. Their ages ranged from 20 to 78: 24.8% in their 30s, 23.4% in their 20s, 22.5% in their 40s in male, and 35.2% in theirs, 22.5% in their 40s, 18.5% in their 20s in female. 9.9% of male and 13.2 % of female had their Family Doctors. The specialties of their Family Doctors were internists in 56.2%, general surgeons in 11.0%. The persons who did not have their family doctors were asked which doctors they would prefer if they had choices of family doctor. The results were internists in 50.3%, family physicians in 13.0%, pediatricians in 4.8%. Only 16.0% residents knew that government tried to introduce Family Doctor Registration Program. The 'Family Doctor Registration Program' was not well known to people. The results of our study showed that more effective incentives and public notifications are needed to activate this program.

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A Comparative Study of Two Different Heel Lancet Devices for Blood Collection in Preterm Infants (미숙아에서 채혈을 위한 발뒤꿈치 천자시 두 종류 천자 기구의 비교)

  • Lim, Hyo-Bin;Rhu, Mi-Joo;Jung, Ji-Mi;Jeon, Ga-Won;Sin, Jong-Beom
    • Neonatal Medicine
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    • v.17 no.2
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    • pp.239-244
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    • 2010
  • Purpose: To evaluate two different heel lancet device in terms of pain response and success of the procedure in the preterm infants undergoing heel puncture. Methods: 100 preterm infants undergoing capillary blood gas analysis or capillary bilirubin monitoring underwent heel puncture, were randomly allocated to blood sampling from the heel with either a conventional manual lancet or an automatic incision device. Primary outcome measures included the Premature Infants Pain Profile (PIPP) score, total duration of procedure, number of heel puncture and number of bruise. The pain response was evaluated using PIPP score and the effectiveness was evaluated using three criteria: total duration of blood sampling, number of puncture, bruising of the heel or ankle. Statistical analysis was performed using the SPSS ver. 13.0 program. Difference between the groups were analysed with t test (continuous variables) and the Chi square test or Fisher test (categorical variables). Results: The mean PIPP score was 4.91 for the automatic lancet group compared with 5.84 for the conventional manual lancet group (P=0.0255).The number of pain scores above 7 during blood collection did not differ between two groups (P=0.2167). The procedure took less time to perform in the automatic lancet group (mean, 30.69 seconds) than in the conventional lancet group (mean, 48.92 seconds) (P<0.0001). Conclusion: This study demonstrated that the automatic lancet device causes less pain and a shorter procedure time than the conventional manual lancet in preterm infants undergoing heel puncture. On the basis of these results the automatic lancet device is very useful method for blood collection in preterm infants by heel puncture.