No abstract available.
Lung*

According to the central limit theorem, the means of a random sample of size, n, from a population with mean, µ, and variance, σ², distribute normally with mean, µ, and variance, σ²/n. Using the central limit theorem, a variety of parametric tests have been developed under assumptions about the parameters that determine the population probability distribution. Compared to non-parametric tests, which do not require any assumptions about the population probability distribution, parametric tests produce more accurate and precise estimates with higher statistical powers. However, many medical researchers use parametric tests to present their data without knowledge of the contribution of the central limit theorem to the development of such tests. Thus, this review presents the basic concepts of the central limit theorem and its role in binomial distributions and the Student's t-test, and provides an example of the sampling distributions of small populations. A proof of the central limit theorem is also described with the mathematical concepts required for its near-complete understanding.
Mathematical Concepts ; Normal Distribution ; Statistical Distributions

In data analysis, given that various statistical methods assume that the distribution of the population data is normal distribution, it is essential to check and test whether or not the data satisfy the normality requirement. Although the analytical methods vary depending on whether or not the normality is satisfied, inconsistent results might be obtained depending on the analysis method used. In many clinical research papers, the results are presented and interpreted without checking or testing normality. According to the central limit theorem, the distribution of the sample mean satisfies the normal distribution when the number of samples is above 30. However, in many clinical studies, due to cost and time restrictions during data collection, the number of samples is frequently lower than 30. In this case, a proper statistical analysis method is required to determine whether or not the normality is satisfied by performing a normality test. In this regard, this paper discusses the normality check, several methods of normality test, and several statistical analysis methods with or without normality checks.
Data Collection ; Methods ; Normal Distribution ; Statistics as Topic

The survival data and the survival analysis are the data and analysis methods used to study the probability of survival. The survival data consist of a period from the juncture of a start event to the juncture of the end event (occurrence event). The period is called the survival period or survival time. In this way, the method of analysing the survival time of subjects and appropriately summarizing the degree of survival is called survival analysis. To understand and analyse survival analysis methods, researchers must be aware of some concepts. Concepts to be aware of in the survival analysis include events, censored data, survival period, survival function, survival curve and so on. This review focuses on the terms and concepts used in the survival analysis. It will also cover the types of survival data that should be collected and prepared when using actual survival analysis method and how to prepare them.
Methods ; Survival Analysis

Background: With the growth of the Internet, social media platforms have emerged as major sources of medical information. We assessed the reliability, quality, and accuracy of the most-viewed YouTube videos containing information on the effect of vitamin C on the common cold. Methods: The YouTube videos were searched on August 1, 2022, using the keywords: (“ascorbic acid” OR “vitamin C” OR “Sodium Ascorbate” OR “L-ascorbic”) AND “common cold”. The 30 most-viewed videos were included in our study. The reliability and quality of the videos were analyzed using modified DISCERN and Global Quality Scales, respectively. When the videos included at least one correct or inaccurate scientific statement about the effect of vitamin C on the common cold, they were classified as accurate or misleading videos, respectively; those without any pertinent information were considered neither accurate nor misleading. If a video contained both accurate and inaccurate statements, it was classified as misleading. Results: Of the 30 most-viewed videos, 73% were unreliable, and 67% contained misleading information and were of a poor quality. Of these 30 videos, 14 videos were produced and posted by customers who were not specialized in medicine or nutrition. Moreover, these videos were of significantly lower reliability, quality, and accuracy than those produced by nutrition or fitness channels or by medical or nutrition professionals. Conclusion The reliability, quality, and accuracy of videos uploaded by non-professionals were low. Therefore, video creators should upload reliable, high-quality videos to ensure the dissemination of accurate medical information.

Purpose: This study aimed to report the results of femorofemoral bypass (FFB) using a great saphenous vein (GSV) graft as an alternative to polytetrafluoroethylene (PTFE) grafts. Materials and Methods: From January 2012 to December 2021, 168 patients who underwent FFB (PTFE, 143; GSV, 25) were included. The patients’ demographic features and surgical intervention results were retrospectively reviewed. Results: There were no intergroup differences in patients’ demographic features.In GSV vs. PTFE grafts, the superficial femoral artery provided statistically significant inflow and outflow (P<0.001 for both), and redo bypass was more common (P=0.021). The mean follow-up duration was 24.7±2.3 months. The primary patency rates at 3 and 5 years were 84% and 74% for PTFE grafts and 82% and 70% for GSV grafts, respectively. There was no significant intergroup difference in primary patency (P=0.661) or clinically driven target lesion revascularization (CD-TLR)-free survival (P=0.758). Clinical characteristics, disease details, and procedures were analyzed as risk factors for graft occlusion. Multivariate analysis revealed that none of the factors was associated with an increased risk of FFB graft occlusion. Conclusion FFB using PTFE or GSV grafts is a useful method with an approximately 70% 5-year primary patency rate. The GSV and PTFE grafts showed no difference in primary patency or CD-TLR–free survival during follow-up; however, FFB using GSV may be an option in selective situations.

OBJECTIVE: To investigate the short-term effects of bipolar radiofrequency applied to sacral nerves to treat neurogenic detrusor overactivity in patients with spinal cord injury. METHODS: Ten patients with spinal cord injury with neurogenic detrusor overactivity were recruited. These subjects were randomized to two groups: intervention (n=5) and control (n=5), members of which received conventional treatment. Voiding diary, International Consultation on Incontinence Questionnaire (ICIQ) and the urinary incontinence quality of life scale (IQOL) data were obtained and an urodynamic study (UDS) was performed before and after intervention. In the intervention group, percutaneous bipolar continuous radiofrequency (CRF) was performed on both the S2 and S3 nerves in each patient. RESULTS: In a comparison of daily frequency and number of urinary incontinence and ICIQ and IQOL scores at baseline and at 1 and 3 months after intervention, all variables achieved a significant effect for time (p<0.05). Regarding UDS parameters, pre/post intervention differences between baseline and 3-month post-intervention for volume at maximal detrusor pressure during filling and reflex detrusor volume at first contraction were significantly different between the two groups (p<0.05). However, pre/post intervention differences in maximum cystometric capacity and maximum detrusor pressure during filling were not significant between the two groups (p>0.05). CONCLUSION: Percutaneous bipolar CRF applied to sacral nerves might be an effective therapy for neurogenic overactive bladder that reduces urinary incontinence and improves quality of life.
Feasibility Studies* ; Humans ; Quality of Life ; Reflex ; Spinal Cord Injuries* ; Spinal Cord* ; Urinary Bladder, Overactive ; Urinary Incontinence ; Urodynamics

The relevance of transglutaminases with neural function and several disorders has been emphasized recently. Especially, many polypeptides associated with neurodegenerative diseases are suggested to be putative transglutaminase substrates such as beta amyloid protein of Alzheimer's disease, microtubule-associated proteins and neurofilaments, etc. In addition, the CAG repeated gene products with probable polyglutamine tract, putative transglutaminase substrates, were identified in several neurodegenerative disorders. However, the identity of the brain transglutaminase has not been confirmed, because of enzymic stability and low activity. In the present experiment, we have isolated brain-specific transglutaminases, designated as TGase NI and TGase NII, which are different from other types of transglutaminases in respects of molecular weights (mw. 45 kDa, 29 kDa respectively), substrate affinity, elution profile on ion-exchange chromatography, sensitivity to proteases and ethanol, and immunological properties. The enzymes were localized specifically in the brain tissues but not in the liver tissue. And neural cells such as pheochromocytoma cell, glioma cell, primary neuronal and glial cells were shown to be enriched with TGase NI and TGase NII. The possible biological roles of the enzymes were discussed not only on the aspect of crosslinking activity but also of signal transducing capacity of the enzyme in the brain.
Animal ; Astrocytes/enzymology ; Blotting, Western ; Brain/enzymology* ; Calcium/metabolism ; Chromatography, Ion Exchange ; Endopeptidases/pharmacology ; Enzyme Stability ; Ethanol/pharmacology ; Glioma ; Immunoblotting ; Immunohistochemistry ; Male ; Molecular Weight ; Neurons/enzymology ; PC12 Cells ; Protein-Glutamine gamma-Glutamyltransferase/isolation & purification* ; Protein-Glutamine gamma-Glutamyltransferase/immunology ; Protein-Glutamine gamma-Glutamyltransferase/chemistry* ; Rats ; Rats, Sprague-Dawley ; Trypsin/pharmacology ; Tumor Cells, Cultured

BACKGROUND: Analyzing the medical care utilization behavior and conception of disease treatment of dermatologic patients is important. However, the Korean literature has few studies reporting this information. OBJECTIVE: The aim of this study is to evaluate medical care utilization behavior and conception of disease treatment of dermatologic patients. METHODS: A written questionnaire concerning personal information, treatment behavior, treatment conception, patient satisfaction, and patient compliance was completed by 442 outpatients who visited the department of dermatology at a university hospital. RESULTS: According to the patients, satisfactory outpatient consultation time for dermatology was 14.2 minutes for the first-visit consultation, and 9.92 minutes for the second-visit consultation. Most (76.0%) patients initially sought the dermatologic clinics for dermatoses, but only 39.8% of patients knew how to distinguish dermatologists from other doctors. Among the participants, 26.7% of patients directly visited a tertiary medical center without visiting primary clinics. Before visiting the hospital, 52.3% of patients sought disease information, and 28.3% of patients obtained information about doctors. Some respondents (39.7%) had a negative attitude about dermatologic medicine because of lay referral. Men were highly satisfied with explanations of drugs and had more positivity towards drugs, but showed low compliance to applying topical medication. Patients of older age, lower education level, and lower economic status had lower satisfaction with explanations given during the examination. CONCLUSION: We advise dermatologists to play a major role in enlightening patients and constructing proper information delivery systems via diversified routes to prevent unreasonable medical care utilization behavior and groundless negative conceptions about dermatologic treatment.
Compliance ; Surveys and Questionnaires ; Dermatology ; Education ; Fertilization ; Humans ; Male ; Outpatients* ; Patient Compliance ; Patient Satisfaction ; Referral and Consultation ; Skin Diseases* ; Skin*

BACKGROUND: The ankle brachial index (ABI) is a useful screening tool for peripheral arterial disease. It has been documented that the cerebral atherosclerosis is more frequent in stroke patients with abnormal ABI than in those with normal ABI. The present study compared the different calculation methods of ABI for coexistent intracranial and extracranial arterial stenosis (IECAS) in ischemic stroke. METHODS: We reviewed the data of patients admitted for acute ischemic stroke or transient ischemic attack. The following four distinct ABIs were calculated: the ratio of the higher (ABI-H), lower (ABI-L), or either of the systolic blood pressures (SBPs) of the posterior tibial (ABI-PT) and dorsalis pedis (ABI-DP) arteries relative to the higher of the brachial SBP. We compared the values of these four ABI measures relative to the presence of any IECAS using receiver operating characteristic (ROC) curve analysis. RESULTS: ABI-H, ABI-L, ABI-PT, and ABI-DP were abnormal (≤ 0.9) in 19 (13.1%), 36 (24.8%), 29 (20%), and 30 (20.7%) of 145 patients, respectively. The area under the ROC curve was significantly larger for ABI-H, ABI-L, and ABI-DP than for ABI-PT for any type of IECAS. The extracranial stenosis was more frequent when any of the four ABIs was abnormal, while intracranial stenosis was not correlated with the four ABIs. The IECAS was more frequent for abnormal ABI-H and ABI-DP than for normal ABIs. CONCLUSIONS: Our studies suggested that ABIs based on a higher SBP of the PT or DP (i.e., ABI-H) are more strongly associated with the presence of IECAS than are those using the SBP of the PT (ABI-PT). Extracranial artery stenosis seems to be more strongly associated with ABI than is intracranial stenosis.
Ankle Brachial Index* ; Ankle* ; Arteries* ; Atherosclerosis ; Constriction, Pathologic* ; Humans ; Intracranial Arteriosclerosis ; Ischemic Attack, Transient ; Mass Screening ; Methods* ; Peripheral Arterial Disease ; ROC Curve ; Stroke*