Design of a CMOS Image Sensor with Bi-Directional Gamma-Corrected Digital-Correlated Double Sampling.

We present a 640 × 480 CMOS image sensor (CIS) with in-circuit bi-directional gamma correction with a proposed digital-correlated double sampling (CDS) structure. To operate the gamma correction in the CIS, the transfer function of the analog-to-digital converter can be changed by controlling the clock frequency of the counter using analog CDS. However, the analog CDS is vulnerable to capacitor mismatch, clock feedthrough, etc. Therefore, we propose a digital-CDS method with a hold-and-go counter structure to operate the bi-directional gamma correction in the CIS. The proposed CIS achieves a 10-bit resolution using a global log-exponential counter and configurable column reset counter with a resolution of 8/9 bits. The sensor was fabricated in a 0.11 µm CIS process, and the full chip area was 5.9 mm × 5.24 mm. The measurement results showed a maximum SNR improvement of 10.41% with the proposed bi-directional gamma-corrected digital-CDS with the hold-and-go counter. The total power consumption was 6.3 mW at a rate of 16.6 frames per second with analog, pixel, and digital supply voltages of 3.3 V, 3.3 V, and 1.5 V, respectively.

High Expression of Tetraspanin 5 as a Prognostic Marker of Colorectal Cancer.

Cancer is a major disease and the leading cause of death worldwide, with colorectal cancer (CRC) being the third-most common cancer in Korea. The survival rate associated with CRC reduces as the disease stage increases. Therefore, its early detection and treatment can greatly increase patient survival rates. In this study, we identified the tetraspanin 5 (TSPAN5) gene as an important biomarker for predicting the prognosis of patients with CRC. A TMA slide was used for statistical analysis. pN and clinical stage were found to be significant factors according to chi-square analysis, whereas pT, pN, metastasis, clinical stage, and TSPAN5 expression were significant according to Cox regression analysis. In order to prove the usefulness of TSPAN5, which is overexpressed in patients with metastatic CRC, as a biomarker, proliferation, migration, invasion, and tumorigenicity were examined using cell lines inhibited using small interfering RNA. The evaluations confirmed that TSPAN5 suppression, in turn, suppressed proliferation, migration, invasion, and tumorigenesis, which are characteristic of cancer cells. Therefore, the evaluation of TSPAN5 expression may help observe the prognosis of CRC and determine an appropriate treatment method for patients with CRC.

Human papillomavirus (HPV) vaccination in males: Associations of HPV-related knowledge and perceptions with HPV vaccination intention among Korean mothers of boys.

Objectives: Human papillomavirus (HPV) vaccination rates among males are suboptimal worldwide. In South Korea, little is known about parents' intention to vaccinate boys against HPV. Therefore, we examined the associations of HPV-related knowledge and perceptions with vaccination intention among Korean mothers of boys. Methods: From August to December 2021, eligible mothers were surveyed about HPV-related knowledge, perceptions, and intention to vaccinate their sons against HPV. Mothers were categorized into no intention, contemplating, and intention to vaccinate groups. Using analysis of variance, we compared the groups' scores on the scales measuring HPV-related knowledge, attitudes, and beliefs. We conducted a multinomial logistic regression analysis to assess the associations between the variables and vaccination intention. Results: Among 361 mothers, 43.9 % had no intention, 60.7 % were contemplating, and 4.4 % intended to vaccinate their sons. The mean percentage of correct answers on the HPV and vaccine knowledge scales were 52.5 % and 62.3 %, respectively. The mean scores on the HPV attitudes and beliefs subscales were significantly different. Higher scores on benefits (OR = 3.04, 95 % CI 1.96 - 4.70; OR = 3.94, 95 % CI 1.54 - 10.70) and influence (OR = 1.48, 95 % CI 1.03 - 2.13; OR = 2.97, 95 % CI 1.44 - 6.14) were associated with contemplating the vaccine and intending to vaccinate sons. Knowledge was not associated with mothers' vaccination intention. Conclusions: Public health authorities and healthcare providers in Korea can use the results of this study to implement effective interventions that emphasize the importance of male HPV vaccination and encourage parent-son communication about the vaccine.

An international survey of physicians regarding clinical trials: a comparison between Kyoto University Hospital and Seoul National University Hospital.

BACKGROUND: International clinical trials are now rapidly expanding into Asia. However, the proportion of global trials is higher in South Korea compared to Japan despite implementation of similar governmental support in both countries. The difference in clinical trial environment might influence the respective physicians' attitudes and experience towards clinical trials. Therefore, we designed a questionnaire to explore how physicians conceive the issues surrounding clinical trials in both countries. METHODS: A questionnaire survey was conducted at Kyoto University Hospital (KUHP) and Seoul National University Hospital (SNUH) in 2008. The questionnaire consisted of 15 questions and 2 open-ended questions on broad key issues relating to clinical trials. RESULTS: The number of responders was 301 at KUHP and 398 at SNUH. Doctors with trial experience were 196 at KUHP and 150 at SNUH. Among them, 12% (24/196) at KUHP and 41% (61/150) at SUNH had global trial experience. Most respondents at both institutions viewed clinical trials favorably and thought that conducting clinical trials contributed to medical advances, which would ultimately lead to new and better treatments. The main reason raised as a hindrance to conducting clinical trials was the lack of personnel support and time. Doctors at both university hospitals thought that more clinical research coordinators were required to conduct clinical trials more efficiently. KUHP doctors were driven mainly by pure academic interest or for their desire to find new treatments, while obtaining credits for board certification and co-authorship on manuscripts also served as motivation factors for doctors at SNUH. CONCLUSIONS: Our results revealed that there might be two different approaches to increase clinical trial activity. One is a social level approach to establish clinical trial infrastructure providing sufficient clinical research professionals. The other is an individual level approach that would provide incentives to encourage doctors to participate in and conduct clinical trials.

Analysis of the factors that influence preschool children eating behavior by applying the health belief model: Seoul and Gyeonggi Province.

BACKGROUND/OBJECTIVES: This study explores the parental characteristics that affect the eating behaviors of preschool children. The nutrition quotient for preschool children (NQ-P) tool was applied to measure the eating behaviors of preschool children, and the relationship between parents' health beliefs and children's eating behaviors was investigated by applying the health belief model. MATERIALS/METHODS: In August 2018, a self-administered online survey was conducted on a sample of parents of children aged 3 to 5 years living in the Seoul and Gyeonggi area. A total of 248 respondents were analyzed via descriptive statistics, one-way ANOVA, Tukey's multiple comparison test, Pearson correlation analysis, and multiple regression analysis. RESULTS: The eating behaviors of preschool children significantly differed based on parents' education level and monthly income (P < 0.01). Among the factors of the health belief model, "perceived benefit" had the highest score at 4.37 points. The multiple regression analysis confirmed that parents' "self-efficacy" raised the NQ-P scores (ß = 0.175, P < 0.05), balance scores (ß = 0.204, P < 0.01), and environment scores of preschool children (ß = 0.149, P < 0.05). The study results showed that if parents are educated on healthy eating habits and their level of self-efficacy for healthy eating practices increases, the formation of correct eating behaviors for preschool children is more likely. CONCLUSION: This study provides preliminary data to develop an education program for parents to understand proper eating behaviors for their children and may help form healthy eating habits and encourage the healthy growth of preschool children.

Human Papillomavirus (HPV) Vaccination Intent among Mothers of Adolescent Sons: A National Survey on HPV Knowledge, Attitudes and Beliefs in South Korea.

PURPOSE: Human papillomavirus (HPV) is one of the most common sexually transmitted infections affecting both males and females but there is an apparent lack of knowledge and apprehension towards male HPV vaccination South Korea. The purpose of the present study was to examine the associations between knowledge and perceptions of male HPV vaccination and vaccination intent among Korean mothers of adolescent sons. MATERIALS AND METHODS: We conducted a cross-sectional study using a nationwide online survey. The independent variables were mothers' sociodemographic characteristics, history of HPV diagnosis, general HPV knowledge, HPV vaccine knowledge, and attitudes and beliefs towards male HPV vaccination. The outcome variable was mothers' intent to vaccinate their sons, which was classified into three categories: non-intent, undecided and intend to vaccinate. We performed univariate analysis and multinomial logistic regression analysis. RESULTS: A total of 906 eligible mothers completed the survey. Mothers received low scores on the HPV-related knowledge scales with low ratings on the scale measuring perceived risk of HPV. Approximately 10% of the mothers intended to vaccinate their sons against HPV, 61.0% were undecided and 1.5% already had their sons vaccinated. According to the multinominal logistic regression analysis, having a daughter in the family, mothers' previous diagnosis with HPV, general HPV knowledge, influence, harm, and risk were significantly associated with being undecided and having intentions to vaccinate their sons (p<0.05). CONCLUSIONS: Our study revealed that Korean mothers are generally less aware of male HPV vaccination, have low perceived risk of HPV, and remain highly hesitant on vaccinating their sons against HPV. It is therefore important to raise public awareness about male HPV vaccination and alleviate vaccine hesitancy. Such efforts will contribute to improving parents' vaccination intent, increasing vaccine uptake among male adolescents and prevention of HPV-associated diseases.

Maternal perceptions of vaccinating boys against human papillomavirus (HPV) in Seoul, South Korea: A descriptive exploratory qualitative study.

Human Papillomavirus (HPV) vaccination is of paramount importance to reduce HPV-associated cancers in both genders. In South Korea, the prophylactic vaccine is recognized as prevention of cervical cancer with little attention given to male HPV vaccination. The purpose of this study was to explore perceptions of male HPV vaccination and underlying factors for vaccine hesitancy among mothers of unvaccinated boys in Seoul, Korea using a qualitative method. We used a purposive sampling strategy to recruit mothers of unvaccinated middle school-aged boys living in one of the 25 districts in Seoul, supplemented by a snowball sampling approach. We conducted one-on-one telephone interviews with ten mothers using a semi-structured interview guide. Questions probed mothers' views on vaccinating boys against HPV and the reasons for not vaccinating their sons. We found that mothers were hesitant to vaccinate their sons against HPV due to high out-of-pocket costs, fear of side effects concerning the young age of their sons, and low awareness of HPV and HPV vaccine, all of which stemmed from the exclusion of male HPV vaccination in the national immunization program. Sociocultural factors, including vaccination norms, lack of HPV education, and values associated with sexually transmitted infections were also likely to negatively impact mothers' vaccination decision-making. Despite the barriers, mothers were willing to accept HPV vaccination when it was framed as cancer prevention for not only the sons but also their future spouses. In conclusion, reasons for Korean mothers' hesitancy for their sons' HPV vaccine uptake were multifaceted. Healthcare providers' role in emphasizing and conveying the importance of gender-neutral HPV vaccination will be essential to alleviate negative sentiments around the vaccine for boys and reduce their risk of compromised sexual health. As an effective public health strategy, tailored cancer prevention messages should be delivered heightening significant benefits of the HPV vaccine beyond the prevention of cervical cancer.

Digital Health Interventions to Improve Adolescent HPV Vaccination: A Systematic Review.

Digital technologies are being increasingly utilized in healthcare to provide pertinent and timely information for primary prevention, such as vaccination. This study aimed to conduct a systematic review to describe and assess current digital health interventions to promote HPV vaccination among adolescents and parents of adolescents, and to recommend directions for future interventions of this kind. Using appropriate medical subject headings and keywords, we searched multiple databases to identify relevant studies published in English between 1 January 2017 and 31 July 2022. We screened and selected eligible studies for inclusion in the final analysis. We reviewed a total of 24 studies, which included interventions using text messages (4), mobile apps (4), social media and websites (8), digital games (4), and videos (4). The interventions generally improved determinants of HPV vaccination, such as HPV-related knowledge, vaccine-related conversations, and vaccination intentions. In particular, text message and social media interventions targeted improved vaccine uptake behaviors, but little meaningful change was observed. In conclusion, digital health interventions can cost-effectively provide education about HPV vaccination, offer interactive environments to alleviate parental vaccine hesitancy, and ultimately help adolescents engage in HPV vaccine uptake.

High expression of LY6E is an independent prognostic factor of colorectal cancer patients.

Colorectal cancer (CRC) is common cancer worldwide, and the 5­year relative survival rate of CRC patients with distant metastasis is as low as 14%. Therefore, identifying markers of CRC is important for the early detection of CRC and applying appropriate treatment strategies. The lymphocyte antigen 6 family (LY6 family) is closely related to the behavior of various cancer types. Among the LY6 family, the lymphocyte antigen 6 complex, locus E (LY6E), which is specifically highly expressed in CRC. Hence, the effects of LY6E on cell function in CRC and its role in CRC recurrence and metastasis were investigated. Reverse transcription­quantitative PCR, western blotting and in vitro functional studies were carried out using four CRC cell lines. Immunohistochemical analysis of 110 CRC tissues was performed to explore the biological functions and expression patterns of LY6E in CRC. LY6E was overexpressed CRC tissues compared with that in adjacent normal tissues. High expression of LY6E in CRC tissues was an independent prognostic factor of worse overall survival (P=0.048). Knockdown of LY6E using small interfering RNA inhibited CRC cell proliferation, migration, invasion, and soft agar colony formation, indicating some of its effects on CRC carcinogenic functions. High expression of LY6E may have oncogenic functions in CRC and be useful as a valuable prognostic marker and potential therapeutic target for CRC.

Trends of genital wart in Korea according to treatment method classification: Big data analysis of health care in 2010-2019.

PURPOSE: The purpose of this study is to investigate disease trend of genital wart through changes in each treatment method over the past 10 years in Korea. MATERIALS AND METHODS: From 2010 to 2019, surgical treatment including cauterization, excision, cryotherapy, and laser therapy, non-surgical treatment such as podophyllin, and surgical treatment for anorectal lesion were extracted and analyzed from 2010 to 2019. For each treatment method, characteristics such as sex, age, region, medical cost and average number of procedures were analyzed. RESULTS: The number of patients following all treatment modalities increased every year. Surgical treatment of genital wart and anorectal wart showed a significant increase in male patients. Number of non-surgical treatment decreased in males but increased in females. Surgical removal of the anorectal wart increased more than 250% in over 10 years, and males underwent surgery 4 times more than females. In both surgery and non-surgery, the mean session was higher in males. Most of them were carried out in primary medical institutions. In Seoul and Gyeonggi-do, the largest number of patients received treatment regardless of treatment method. CONCLUSIONS: Treatment for genital warts has increased rapidly over the past 10 years, and the increase in males is remarkable. The main treatment was surgery, and males mainly received surgical treatment, and females mainly received drug treatment. The primary medical institution was in charge of the most treatment. As the number of patients and related medical expenses are increasing rapidly, more attention and response to diseases are needed.

Expression of Spermine Oxidase Is Associated with Colorectal Carcinogenesis and Prognosis of Patients.

Uncovering tumor markers of colorectal cancer is important for the early detection and prognosis of the patients. Spermine oxidase (SMOX) is upregulated in various cancers. The present study aims to explore the biologic function and expression patterns of SMOX in colorectal cancer (CRC), the third most common type of cancer worldwide. We used quantitative real-time PCR, Western blot, and in vitro functional studies in four CRC cell lines knocked down by SMOX siRNA and immunohistochemistry in 350 cases of CRC tissues. The results showed that SMOX was overexpressed in CRC cell lines and clinical samples. SMOX overexpression in tumor tissues was an independent prognostic factor, worsening overall survival (p = 0.001). The knock-down of SMOX inhibited CRC cell proliferation, invasion, and soft agar colony formation, uncovering its carcinogenic functions. This study indicated that SMOX overexpression could be an important oncogene in CRC and might serve as a valuable prognostic marker and potential therapeutic target for CRC.

The Patterns and Characteristics of Esoteric Buddhist Therapies during Goryeo Dynasty.

This study focused its investigation on esoteric Buddhist treatment methods during Goryeo. In Goryeo, they published dharani scriptures related to illness. Beomseo-chongji-jip, a collection of dharanis, contains few dharanis for treatment. The publication of a dharani scripture was a precondition of dharani-based Buddhist prayers. There had been cases of treating illness through Buddhist prayers based on a dharani since ancient times, and Hyetong of Samgukyusa is a good example. The religious sect of esoteric Buddhism that inherited the line of Hyetong in Goryeo was Chongji-jong, which seems to have been partially responsible for royal medicine and engaged in relief activities for people to end an infectious disease. During the period of Yuan's interventions, Yeom Seung-ik became a favorite of the king for his ability of treating illness through his spells. He was not a Buddhist monk, and his case reflects the wide spread of disease-treating spells among common people those days. The establishment of a ritual was one of the traditional therapies. In Goryeo, various esoteric Buddhist rituals were held for therapeutic purposes. Marijicheon-doryang, Gongjakwang-doryang, and Buljeongsim-doryang were established to expel infectious diseases, and Sojae-doryang and Boseong-doryang were established to treat the illness of kings and queens. They were intended to treat illness by eliminating the causes of epidemics and diseases by the virtue of dharanis. Esoteric Buddhist therapies containing Taoist elements were also developed. The utilization of Eight-Gate Transformation and talismans are the exampels. In early Joseon, Buddhist monks of Chongji-jong were said to have contributed to the treatment of diseases by using Eight-Gate Transformation. They were used to predict a good direction for the treatment of a patient. This practice of Chongji-jong Buddhist monks in early Joseon seems to have inherited the heritage of Goryeo, which suggests that Eight-Gate Transformation was one of the therapies practiced by esoteric Buddhist monks in Goryeo. Talismans are commonly known to be used in Taoism and shamanism, but Buddhist scriptures, especially esoteric Buddhist scriptures, contain a variety of talismans. Buljeongsim-darani-gyeong has talismans on its last page and records that one can treat his or her illness by burning the talisman and taking its ash. This therapy proposed by this scripture seems to have enjoyed considerable popularity in Goryeo, when its simplified versions comprised only of dharani phrases and talismans were made. These various esoteric Buddhist therapies demonstrate that human beings made utmost efforts to overcome their personal and social crises. Therapies are a total reflection of a society's contemporary politics, religion, ideas, and culture. Esoteric Buddhist therapies may seem like superstitions in the eyes of modern people, but they must have been reliable treatment methods whose efficacy was guaranteed within the thinking system of people during Goryeo.

Evaluation of dietary behaviors of preschool children in Seoul and Gyeonggi-do associated with the level of parents' health consciousness: using nutrition quotient for preschoolers (NQ-P).

BACKGROUND/OBJECTIVES: This study aimed to assess the dietary behaviors of preschool children using the nutrition quotient for preschoolers (NQ-P) and analyzed the difference in the scores of the children's dietary behaviors in regards to the parents' health consciousness. SUBJECTS/METHODS: The subjects were 257 children aged 3-5 years and their parents residing in Seoul and Gyeonggi-do, South Korea. The questionnaire is composed of demographic characteristics, the NQ-P questions, and health consciousness. All data were statistically analyzed by SPSS program (ver. 25.0) and the statistical differences in variables were evaluated by χ2 test, Fisher's exact test, t-test, 1-way analysis of variance and Tukey's multiple comparison test. RESULTS: There was a significant difference on the intake frequency of processed meat by region and fast foods by age, region, and weight status (P < 0.05). There was also a significant difference in not moving around while eating by weight status and parents' effort to have healthy eating habits by sex (P < 0.05). The mean score of NQ-P of the total subjects was 59.47, which was within the medium-low grade. The mean score of balance was 61.62, and the boys were significantly higher than girls (P < 0.05). As the age of children increased, the mean score of the moderation was significantly decreased (P < 0.05). The scores of NQ-P (P < 0.05), balance (P < 0.01), and environment (P < 0.05) were significantly higher in the high group of parents' health consciousness than the low group. CONCLUSIONS: According to the results of the evaluation by NQ-P, the dietary behaviors of preschoolers residing in Seoul and Gyeonggi-do need to be improved. For improving their eating behavior and nutritional health status, parents and children need customized nutrition education programs based on sex, age, region and weight status of preschool children as well as the degree of parents' health consciousness.

Depth-Dependent Cellular Response from Dental Bulk-Fill Resins in Human Dental Pulp Stem Cells.

The proper choice of dental composite resins is necessary based on the minimal cytotoxicity and antiodontogenesis on human dental pulp stem cells for dental pulp-dentin tissue repair and regeneration. The aim of this study was to evaluate the cytotoxicity and antidifferentiation effects of dental bulk-fill resins, able to be polymerized as a bulk status for filling deep cavity of a tooth by single light curing, against human dental pulp stem cells (hDPSCs) from three compartments corresponding to depth (0-2, 2-4, and 4-6 mm) from the light-curing site. Three bulk-fill composite resins (SDR, Venus bulk-fill (VBF), and Beautifil Bulk Flowable (BBF)) and a conventional flowable composite resin (Filtek Z350 XT flowable restorative (ZFF)) were individually filled into a cylindrical hole (h = 2 mm, Ф = 10 mm), and three compartments (total ~6 mm of height) were combined as a single assembly for light curing. The resin samples from the three layers were separated and eluted in the culture medium. The extracts were exposed to hDPSCs, and cytotoxicity and differentiation capability were evaluated. Depth of cure and surface hardness according to depth were determined. All bulk-fill resins except BBF revealed cytotoxicity from 4 to 6 or 2 to 4 mm, while ZFF was cytotoxic at over 2 mm. Depth of cure was detected from 3.55 to 4.02 mm in the bulk-fill resins (vs. ~2.25 mm in conventional resin), and 80% hardness compared with that of a fully polymerized top surface was determined from 4.2 to 6 mm in the bulk-fill resin (vs. 2.4 mm in conventional resin). Antidifferentiation was revealed at a depth of 4-6 mm in the bulk-fill resin. There was a difference in depth of cytotoxicity and antidifferentiation between the bulk-fill composite resins, which was mainly due to different cure depths and ingredients. Therefore, careful consideration of choice of bulk-fill resins is necessary especially for restoration of deep cavities for maintaining the viability and differentiation ability of dental pulp stem cells.

[The health care in North Korea during the period (1945-1948) between liberation from Japanese occupation and establishment of North Korean government].

This paper, mainly based on literature and documents from North Korea and Russia, described how health care system had been formulated during the period of between liberation from Japanese Occupation and formation of its own government in North Korea, which is so-called 'the Period of People's Democracy'. North Korea authorities, by themselves, address that their health care system is characterized by state medicine, universal free medical care, emphasis on preventive medicine, community(ho) doctors in charge, provisions of modern medical services in parallel with traditional ones, imposed high value on ideologies of medical personnel, and mass participation of health programs so on, taken rise since this period. Under North Korea's socialistic regime, authorities started to restructure health care system through national health care organizations and institutes, which partially provided medical service free. Also, they emphasized preventive medicine against 'capitalistic' treatment-oriented medicine, and community(ho) doctor in-charge was derived from this period. It showed that the mass participation on health program was equal hereafter and they had under bias toward more emphasis on ideology of medical personnel rather than their professionalism. The attempt to develop traditional medicine had been made during this period, however, much funding and support was not observed. In this period, it showed that a series of action to restructure health care system had been gradually carried out.

[The influence of the devotion movement on the health care in North Korea].

Since the early 1960s, North Korea has conducted 'devotion movement' under the directorship of Kim Il Sung across the nation. As a matter of fact, the movement was not a novel invention at all. When North Korean Temporary People's Polity was established in 1946, North Korea emphasized the importance of the devoted care of health personnel. It meant to reform the people's thought and mind along with complementing the lack of human and material resources. Thought reform was not a peculiar phenomenon observed in North Korea only. It was particularly stressed out among communist countries, including the Soviet Union. However any other communist country stresses the importance of thought reform. Devotion movement should be viewed as part of this process. As shown in many cases, the extent and degree of devotion movement and care are beyond our imagination, which does not intend to mean that North Korean health personnel's attitude towards patients is superior to the counterparts in South Korea. Indeed human being's behavior cannot be understood without taking account of society in general. The question can be raised as to whether or not North Korean health personnel's devoted care is really voluntary. To put aside the testimony that the most powerless group in a society can fall prey to victims, if social environment, whether directly or indirectly, is action on the people's thought and mind even in a subtle way and thus influence one's decision power, it is hard to highly evaluate the devoted care in North Korea. Moreover it seems like that the internal conflict exists surrounding devotion. In conclusion, I think that North Korean devotion movement has enforced health personnel to reform their thought and mind to adapt to North Korean regime and has played an important role to accomplish the purpose of North Korean Labor Party to realize essential constituents of its health system, in such a situation in which essential medical supplies are severely lacking. But it seems like that it plays reverse action to develope sound North Korean health system.

Assessing medical students' and residents' perceptions of the learning environment: exploring validity evidence for the interpretation of scores from existing tools.

PURPOSE: Although most agree that supportive learning environments (LEs) are essential for effective medical education, an accurate assessment of LE quality has been challenging for educators and administrators. Two previous reviews assessed LE tools used in the health professions; however, both have shortcomings. The primary goal of this systematic review was to explore the validity evidence for the interpretation of scores from LE tools. METHOD: The authors searched ERIC, PsycINFO, and PubMed for peer-reviewed studies that provided quantitative data on medical students' and/or residents' perceptions of the LE published through 2012 in the United States and internationally. They also searched SCOPUS and the reference lists of included studies for subsequent publications that assessed the LE tools. From each study, the authors extracted descriptive, sample, and validity evidence (content, response process, internal structure, relationship to other variables) information. They calculated a total validity evidence score for each tool. RESULTS: The authors identified 15 tools that assessed the LE in medical school and 13 that did so in residency. The majority of studies (17; 61%) provided some form of content validity evidence. Studies were less likely to provide evidence of internal structure, response process, and relationship to other variables. CONCLUSIONS: Given the limited validity evidence for scores from existing LE tools, new tools may be needed to assess medical students' and residents' perceptions of the LE. Any new tools would need robust validity evidence testing and sampling across multiple institutions with trainees at multiple levels to establish their utility.