J-shaped Relationship Between Chronic Kidney Disease and Serum Uric Acid Levels: A Cross-sectional Study on the Korean Population

Objective@#Both hypouricemia and hyperuricemia are reportedly associated with reduced kidney function. This study investigated the association between uric acid levels and the risk of reduced renal function in men and women. @*Methods@#We conducted a cross-sectional study using data from a government-funded health examinee cohort of a Korean genome and epidemiological study. A total of 172,970 participants (58,981 men, 113,989 women) aged 40∼79 years were included. A logistic regression test was performed, and the odds ratio (OR) and 95% confidence interval (CI) were calculated to examine the relationship between stratified uric acid levels and the frequency of chronic kidney disease. @*Results@#As the uric acid level increased, the risk of reduced renal function increased. Moreover, for uric acid levels ≤2.0 mg/dL, the risk of reduced renal function was higher than that of the reference group. Among the total, man, and woman groups, a statistically significant association was observed in men (OR 1.71, 95% CI 0.945∼3.111, OR 5.003, 95% CI 1.405∼17.809, and OR 1.377, 95% CI 0.696∼2.724, respectively). @*Conclusion@#The OR of reduced renal function according to uric acid levels formed a J-shaped curve in both genders.

Bath Ankylosing Spondylitis Disease Activity Index is Associated With the Quality of Sleep in Ankylosing Spondylitis Patients

Objective@#High disease activity of ankylosing spondylitis (AS) is associated with poor sleep quality. The purpose of this study was to identify which of the representative tools for evaluating the disease activity of AS best reflect the quality of sleep. @*Methods@#A total of 107 AS patients were enrolled in the study and the sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Age, sex, concomitant medication, erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) level, Beck Depression Inventory second edition (BDI-II), Bath ankylosing spondylitis disease activity index (BASDAI), ankylosing spondylitis disease activity score (ASDAS)-ESR, ASDAS-CRP, pain visual analog scale, Insomnia Severity Index (ISI), and Epworth Sleepiness Scale (ESS) were analyzed as covariates. @*Results@#Overall, 65% (70/107) of subjects reported poor sleep quality (PSQI＞5). There was a positive correlation between the sleep quality and disease activity as measured by the BASDAI, ASDAS-ESR, and ASDAS-CRP. In addition, the BASDAI demonstrated good correlations with ISI, ESS, and BDI-II, respectively. However, only BASDAI showed reliable correlation with PSQI among the disease activity parameters of AS (adjusted odd ratio 5.36, p=0.023). @*Conclusion@#BASDAI is the most reliable parameter of disease activity associated with the sleep quality in patients with AS.

J-shaped Relationship Between Chronic Kidney Disease and Serum Uric Acid Levels: A Cross-sectional Study on the Korean Population

Objective@#Both hypouricemia and hyperuricemia are reportedly associated with reduced kidney function. This study investigated the association between uric acid levels and the risk of reduced renal function in men and women. @*Methods@#We conducted a cross-sectional study using data from a government-funded health examinee cohort of a Korean genome and epidemiological study. A total of 172,970 participants (58,981 men, 113,989 women) aged 40∼79 years were included. A logistic regression test was performed, and the odds ratio (OR) and 95% confidence interval (CI) were calculated to examine the relationship between stratified uric acid levels and the frequency of chronic kidney disease. @*Results@#As the uric acid level increased, the risk of reduced renal function increased. Moreover, for uric acid levels ≤2.0 mg/dL, the risk of reduced renal function was higher than that of the reference group. Among the total, man, and woman groups, a statistically significant association was observed in men (OR 1.71, 95% CI 0.945∼3.111, OR 5.003, 95% CI 1.405∼17.809, and OR 1.377, 95% CI 0.696∼2.724, respectively). @*Conclusion@#The OR of reduced renal function according to uric acid levels formed a J-shaped curve in both genders.

Bath Ankylosing Spondylitis Disease Activity Index is Associated With the Quality of Sleep in Ankylosing Spondylitis Patients

Objective@#High disease activity of ankylosing spondylitis (AS) is associated with poor sleep quality. The purpose of this study was to identify which of the representative tools for evaluating the disease activity of AS best reflect the quality of sleep. @*Methods@#A total of 107 AS patients were enrolled in the study and the sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Age, sex, concomitant medication, erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) level, Beck Depression Inventory second edition (BDI-II), Bath ankylosing spondylitis disease activity index (BASDAI), ankylosing spondylitis disease activity score (ASDAS)-ESR, ASDAS-CRP, pain visual analog scale, Insomnia Severity Index (ISI), and Epworth Sleepiness Scale (ESS) were analyzed as covariates. @*Results@#Overall, 65% (70/107) of subjects reported poor sleep quality (PSQI＞5). There was a positive correlation between the sleep quality and disease activity as measured by the BASDAI, ASDAS-ESR, and ASDAS-CRP. In addition, the BASDAI demonstrated good correlations with ISI, ESS, and BDI-II, respectively. However, only BASDAI showed reliable correlation with PSQI among the disease activity parameters of AS (adjusted odd ratio 5.36, p=0.023). @*Conclusion@#BASDAI is the most reliable parameter of disease activity associated with the sleep quality in patients with AS.

Distribution of serum uric acid levels and prevalence of hyper- and hypouricemia in a Korean general population of 172,970

Background/Aims@#We investigated the distribution of serum uric acid (SUA) levels and estimated the prevalence of hyperuricemia and hypouricemia in the Korean population. @*Methods@#This cross-sectional study used data from the Korean Genome and Epidemiology Study and included 172,970 participants (58,981 men and 113,989 women) aged 40 to 79 years. Hypouricemia and hyperuricemia were defined as SUA level ≤ 2.0 mg/dL and > 7 mg/dL, respectively. The prevalence of hyperuricemia and hypouricemia was evaluated by age and sex. @*Results@#The mean SUA levels were significantly higher in men than in women (5.71 ± 1.27 mg/dL vs. 4.21 ± 0.96 mg/dL, p < 0.001). The mean SUA levels and prevalence of hyperuricemia increased with age in women but not in men. The overall prevalence of hyperuricemia and that in men and women was 50.82, 133.25, and 8.17 per 1,000 persons, respectively; the overall prevalence of hypouricemia and that in men and women was 4.16, 1.10, and 5.75 per 1,000 persons, respectively. The prevalence of hypouricemia in men was similar across all age groups; however, that in women was the highest in the age group of 40 to 49 years and the lowest in the age group of 50 to 59 years. @*Conclusions@#The distribution of SUA levels and prevalence of hyperuricemia and hypouricemia differed according to age and sex. Age and sex should be considered in studies on uric acid-related diseases.

Clinical Significance of Elevated Serum Immunoglobulin G4 Levels in Patients With Rheumatoid Arthritis

OBJECTIVE: This study aimed to evaluate the relationship between serum immunoglobulin G4 (IgG4) levels and the presence and disease activity of rheumatoid arthritis (RA).METHODS: The study enrolled 128 participants (RA, 96; healthy controls, 17; osteoarthritis, 11; and IgG4-related disease, 4) between March 2014 and July 2017. Blood samples were collected prior to the commencement of treatment, and serum IgG4 levels were determined using a nephelometric assay (levels ≥135 mg/dL were considered elevated). The levels of serum IgG4 and the ratio of IgG4/total IgG in patients with RA were compared with those in healthy controls, patients with osteoarthritis, and patients with IgG4-related disease. Furthermore, the relationship between serum IgG4 levels and RA disease activity was evaluated.RESULTS: Among the 96 patients with RA, the mean (±standard deviation) serum IgG4 level was 48.0±45.4 mg/dL; 6 (6.3%) patients had elevated serum IgG4 levels. However, none of the healthy controls or patients with osteoarthritis had elevated serum IgG4 levels. The mean serum IgG4/IgG ratio in patients with RA was 3.5%±2.8% (range, 0.2%~16.9%). Using Spearman's correlation coefficient analysis, a significant correlation was found between serum IgG4 levels and the Disease Activity Score-28 with erythrocyte sedimentation rate (r, 0.245; p=0.016).CONCLUSION: There was an increased frequency of elevated serum IgG4 levels in patients with RA, and the levels were correlated with RA disease activity.

Engineering Human Brain Organoids: From Basic Research to Tissue Regeneration

BACKGROUND@#Brain organoids are self-organized from human pluripotent stem cells and developed into various brain region following the developmental process of brain. Brain organoids provide promising approach for studying brain development process and neurological diseases and for tissue regeneration. @*METHODS@#In this review, we summarized the development of brain organoids technology, potential applications focusing on disease modeling for regeneration medicine, and multidisciplinary approaches to overcome current limitations of the technology. @*RESULTS@#Generations of brain organoids are categorized into two major classes by depending on the patterning method.In order to guide the differentiation into specific brain region, the extrinsic factors such as growth factors, small molecules, and biomaterials are actively studied. For better modelling of diseases with brain organoids and clinical application for tissue regeneration, improvement of the brain organoid maturation is one of the most important steps. @*CONCLUSION@#Brain organoids have potential to develop into an innovative platform for pharmacological studies and tissue engineering. However, they are not identical replicas of their in vivo counterpart and there are still a lot of limitations to move forward to clinical applications.

Engineering Human Brain Organoids: From Basic Research to Tissue Regeneration

BACKGROUND@#Brain organoids are self-organized from human pluripotent stem cells and developed into various brain region following the developmental process of brain. Brain organoids provide promising approach for studying brain development process and neurological diseases and for tissue regeneration. @*METHODS@#In this review, we summarized the development of brain organoids technology, potential applications focusing on disease modeling for regeneration medicine, and multidisciplinary approaches to overcome current limitations of the technology. @*RESULTS@#Generations of brain organoids are categorized into two major classes by depending on the patterning method.In order to guide the differentiation into specific brain region, the extrinsic factors such as growth factors, small molecules, and biomaterials are actively studied. For better modelling of diseases with brain organoids and clinical application for tissue regeneration, improvement of the brain organoid maturation is one of the most important steps. @*CONCLUSION@#Brain organoids have potential to develop into an innovative platform for pharmacological studies and tissue engineering. However, they are not identical replicas of their in vivo counterpart and there are still a lot of limitations to move forward to clinical applications.

18FTHK5351 PET Imaging in Patients with Mild Cognitive Impairment

Background@#and PurposeMild cognitive impairment (MCI) is a condition with diverse clinical outcomes and subgroups. Here we investigated the topographic distribution of tau in vivo using the positron emission tomography (PET) tracer [18F]THK5351 in MCI subgroups. @*Methods@#This study included 96 participants comprising 38 with amnestic MCI (aMCI), 21 with nonamnestic MCI (naMCI), and 37 with normal cognition (NC) who underwent 3.0-T MRI, [18F]THK5351 PET, and detailed neuropsychological tests. [18F]flutemetamol PET was also performed in 62 participants. The aMCI patients were further divided into three groups: 1) verbal-aMCI, only verbal memory impairment; 2) visual-aMCI, only visual memory impairment; and 3) both-aMCI, both visual and verbal memory impairment. Voxel-wise statistical analysis and region-of-interest -based analyses were performed to evaluate the retention of [18F]THK5351 in the MCI subgroups. Subgroup analysis of amyloid-positive and -negative MCI patients was also performed. Correlations between [18F]THK5351 retention and different neuropsychological tests were evaluated using statistical parametric mapping analyses. @*Results@#[18F]THK5351 retention in the lateral temporal, mesial temporal, parietal, frontal, posterior cingulate cortices and precuneus was significantly greater in aMCI patients than in NC subjects, whereas it did not differ significantly between naMCI and NC participants. [18F] THK5351 retention was greater in the both-aMCI group than in the verbal-aMCI and visualaMCI groups, and greater in amyloid-positive than amyloid-negative MCI patients. The cognitive function scores were significantly correlated with cortical [18F]THK5351 retention. @*Conclusions@#[18F]THK5351 PET might be useful for identifying distinct topographic patterns of [18F]THK5351 retention in subgroups of MCI patients who are at greater risk of the progression to Alzheimer's dementia.

Relationships between ¹⁸F-THK5351 Retention and Language Functions in Primary Progressive Aphasia

BACKGROUND AND PURPOSE: There are three distinct subtypes of primary progressive aphasia (PPA): the nonfluent/agrammatic variant (nfvPPA), the semantic variant (svPPA), and the logopenic variant (lvPPA). We sought to characterize the pattern of [¹⁸F]-THK5351 retention across all three subtypes and determine the topography of [¹⁸F]-THK5351 retention correlated with each neurolinguistic score. METHODS: We enrolled 50 participants, comprising 13 PPA patients (3 nfvPPA, 5 svPPA, and 5 lvPPA) and 37 subjects with normal cognition (NC) who underwent 3.0-tesla magnetic resonance imaging, [¹⁸F]-THK5351 positron-emission tomography scans, and detailed neuropsychological tests. The PPA patients additionally participated in extensive neurolinguistic tests. Voxel-wise and region-of-interest-based analyses were performed to analyze [¹⁸F]-THK5351 retention. RESULTS: The nfvPPA patients exhibited higher [¹⁸F]-THK5351 retention in the the left inferior frontal and precentral gyri. In svPPA patients, [¹⁸F]-THK5351 retention was elevated in the anteroinferior and lateral temporal cortices compared to the NC group (left>right). The lvPPA patients exhibited predominant [¹⁸F]-THK5351 retention in the inferior parietal, lateral temporal, and dorsolateral prefrontal cortices, and the precuneus (left>right). [¹⁸F]-THK5351 retention in the left inferior frontal area was associated with lower fluency scores. Comprehension was correlated with [¹⁸F]-THK5351 retention in the left temporal cortices. Repetition was associated with [¹⁸F]-THK5351 retention in the left inferior parietal and posterior temporal areas, while naming difficulty was correlated with retention in the left fusiform and temporal cortices. CONCLUSIONS: The pattern of [¹⁸F]-THK5351 retention was well matched with clinical and radiological findings for each PPA subtype, in agreement with the anatomical and functional location of each language domain.

The Relationship between Thyroid Nodules Detected through Ultrasonography and Thyroid Function Test Results in Healthy Individuals

BACKGROUND: The detection of thyroid nodules through ultrasonography (US) has improved with the development of imaging technologies and thyroid cancer screening in Korea. We evaluated the relationship between the presence of thyroid nodules on US and thyroid function test (TFT) results in healthy individuals.METHODS: We performed a retrospective review of data from 449 adults (313 men and 136 women) who underwent tests to evaluate serum thyrotropin (TSH) and free thyroxine levels, thyroid US, and if needed, fine needle aspiration cytology (FNAC).RESULTS: Of the 449 subjects, 144 subjects (32.1%) had thyroid nodules. Among the 144 with thyroid nodules, 24 (16.7%) were advised to undergo FNAC, and all of them showed normal serum TSH levels. Logistic regression analysis showed that the presence of thyroid nodules was not related to abnormalities noted on TFTs after adjusting for age, sex, smoking status, and presence of risky drinking behavior and hypertension (P=0.647).CONCLUSION: The presence of thyroid nodules on US in healthy adults was not associated with abnormal TFT results. Serum TSH check-ups during the evaluation of thyroid nodules discovered through US in asymptomatic individuals living in areas with a low prevalence of autonomous functioning thyroid nodules might not be necessary from the perspective of cost-effectiveness and subject convenience.

¹⁸F-THK5351 PET Imaging in the Behavioral Variant of Frontotemporal Dementia

BACKGROUND AND PURPOSE: Behavioral variant frontotemporal dementia (bvFTD) is a subtype of frontotemporal dementia, which has clinical symptoms of progressive personality and behavioral changes with deterioration of social cognition and executive functions. The pathology of bvFTD is known to be tauopathy or TDP-43 equally. We analyzed the 18F-THK5351 positron emission tomography (PET) scans, which were recently developed tau PET, in patients with clinically-diagnosed bvFTD. METHODS: Forty-eight participants, including participants with behavioral variant frontotemporal dementia (bvFTD, n=3), Alzheimer's disease (AD, n=21) and normal cognition (NC, n=24) who completed 3T magnetic resonance images, 18F-THK5351 PET scans, and detailed neuropsychological tests were included in the study. Voxel-wise statistical analysis and region of interest (ROI)-based analyses were performed to evaluate the retention of THK in bvFTD patients. RESULTS: In the voxel-based and ROI-based analyses, patients with bvFTD showed greater THK retention in the prefrontal, medial frontal, orbitofrontal, anterior cingulate, insula, anterior inferior temporal and striatum regions compared to NC participants. Left-right asymmetry was noted in the bvFTD patients. A patient with extrapyramidal symptoms showed much greater THK retention in the brainstem. CONCLUSIONS: The distribution of THK retention in the bvFTD patients was mainly in the frontal, insula, anterior temporal, and striatum regions which are known to be the brain regions corresponding to the clinical symptoms of bvFTD. Our study suggests that 18F-THK5351 PET imaging could be a supportive tool for diagnosis of bvFTD.

¹⁸F-THK5351 PET Imaging in Nonfluent-Agrammatic Variant Primary Progressive Aphasia

BACKGROUND AND PURPOSE: To analyze 18F-THK5351 positron emission tomography (PET) scans of patients with clinically diagnosed nonfluent/agrammatic variant primary progressive aphasia (navPPA). METHODS: Thirty-one participants, including those with Alzheimer's disease (AD, n=13), navPPA (n=3), and those with normal control (NC, n=15) who completed 3 Tesla magnetic resonance imaging, 18F-THK5351 PET scans, and detailed neuropsychological tests, were included. Voxel-based and region of interest (ROI)-based analyses were performed to evaluate retention of 18F-THK5351 in navPPA patients. RESULTS: In ROI-based analysis, patients with navPPA had higher levels of THK retention in the Broca's area, bilateral inferior frontal lobes, bilateral precentral gyri, and bilateral basal ganglia. Patients with navPPA showed higher levels of THK retention in bilateral frontal lobes (mainly left side) compared than NC in voxel-wise analysis. CONCLUSIONS: In our study, THK retention in navPPA patients was mainly distributed at the frontal region which was well correlated with functional-radiological distribution of navPPA. Our results suggest that tau PET imaging could be a supportive tool for diagnosis of navPPA in combination with a clinical history.

The relationship between anti-C-reactive protein and disease activity in patients with systemic lupus erythematosus

BACKGROUND/AIMS: Anti-C-reactive protein (CRP) antibody has been introduced as a potential biologic marker in Systemic lupus erythematosus (SLE). The aim of study is to evaluate the level of anti-CRP antibody in patients with SLE. METHODS: This study investigated the relationship between levels of anti-CRP antibodies and disease activity markers, such as complement, anti-double-stranded DNA antibody, and SLE disease activity index in 34 patients with SLE. RESULTS: The serum anti-CRP antibody levels of the patients with SLE were significantly higher than those of the healthy controls (11.3 ± 5.6 µg/mL vs. 9.1 ± 2.8 µg/mL). The percentages of the positive anti-CRP antibody were 52.9% in SLE and 27.8% in controls. Disease duration of SLE showed significant correlation with the anti-CRP antibody (r = 0.234, p = 0.026). However no significant relationship was observed between the levels of anti-CRP antibodies and disease activity markers. CONCLUSIONS: These data show that the anti-CRP antibody levels of the patients with SLE were significantly higher than those of healthy controls. We observed that the presence of the anti-CRP anti-CRP antibody was not associated with disease activity of SLE.

A Case of Refractory Oral Aphthous Ulcer Successfully Treated with Adalimumab

Oral aphthous ulcer is a common lesion characterized by loss of dermal tissue of various shapes in many diseases. It is not serious, but may affect quality of life through pain and discomfort. In many cases, it heals spontaneously without treatment or with topical agents such as antiseptics, analgesics and corticosteroid in a few days. However, rarely, there are a few cases of aphthous ulcer that remain refractory despite appropriate treatment. Tumor necrosis factor-α inhibitors have recently been used in treatment of severe mucosal ulcer in Behçet's disease. Herein, we report a patient suffering from refractory oral aphthous ulcers that were resistant to topical and systemic agents, but were successfully treated with adalimumab.

Association of sleep quality in Behcet disease with disease activity, depression, and quality of life in Korean population

BACKGROUND/AIMS: Sleep disturbance is prime concern in patients with Behcet disease. The purpose of this study was to find out the effects of sleep quality, in Korean patients suffering from Behcet disease. We further investigated the relationship between depression, quality of life and the clinical findings of Behcet disease. METHODS: The study was performed by the cross-sectional design. Sleep quality was assessed by the Korean version of Pittsburgh sleep quality index (PSQI). Disease activity of Behcet disease was evaluated by Behcet disease current activity form (BDCAF). Depression was assessed by the Korean version of Beck depression inventory second edition (BDI-2). Quality of life was assessed by the Korean version of the Leeds Behcet disease quality of life measure (BDQoL). RESULTS: Among the 100 patients studied, 42% reported poor sleep quality (PSQI ≥ 9). These patients have a higher BDI-2, total BDCAF and pain visual analogue scale (VAS) score (p < 0.001, p = 0.022, and p = 0.005). Considering BDCAF, the frequency of genital ulcer was significantly higher (p = 0.01). Behcet was higher in females. The BDQoL was lower in poor sleeper group (p = 0.004 and p < 0.001). Among 7 PSQI components, daytime dysfunction was higher in patients with high disease activity (p = 0.03). Total PSQI score were strongly correlated with BDCAF, BDI-2, BDQoL, and pain VAS score (p = 0.02, p < 0.001, p < 0.001, and p < 0.001, respectively). CONCLUSIONS: Low sleep quality is directly associated with disease activity, depression, and quality of life in Korean patients with Behcet disease.

Health Literacy and Its Related Factors in North Korean Refugees

BACKGROUND: In September 2016, the number of North Korean refugees living in South Korea was 29,688. They have been struggling with health problems due to their poor health status and the differences in medical system and terminology between South and North Korea. We aimed to investigate the level of health literacy and its related factors in North Korean refugees. METHODS: This study was conducted with 142 patients who visited North Korean refugees' counseling center at Seoul Medical Center and National Central Medical Center and 100 South Korean patients who visited outpatient clinics or Health Promotion Center of Seoul Medical Center. General and health-related characteristics were surveyed through a questionnaire and health literacy was measured by using ‘Korean Adult Health Literacy Scale’. RESULTS: The average age of North Korean refugees was 48.92±11.49 years old. Almost 95% reported that their monthly income was less than 2 million KRW. The survey showed that North Korean refugees obtain health information mainly through TV, radio, and acquaintances and more than half (54.9%) said their health was bad or very bad. The mean score of North Korean refugees' health literacy was much lower than that of South Koreans (12.42±7.58 vs. 25.3±5.7, P<0.001). This discrepancy was maintained after adjusting related factors such as age, sex, and socioeconomic status with stratified analysis. CONCLUSIONS: It suggest the urgent need for policies which support for futher researches and development of education system, which may lead to the improvememt of the health literacy of North Korean regugees.

Liver Regenerating Potential of the Secretome Obtained from Adipose-derived Stem Cells Cultured under the Hypoxic Environment / 대한이식학회지

BACKGROUND: The stem cell-derived secretome has received considerable attention as an alternative to stem cells for therapeutic applications. However, establishing optimal culture conditions is key to obtaining appropriate secretome contents. Here, the optimal culturing environment for achieving a high-efficiency secretome was determined via hypoxic preconditioning of human adipose-derived stem cells (ASC). METHODS: Normoxic conditioned media (NCM) and hypoxic conditioned media (HCM) were obtained after culturing human ASCs under normoxia (20% O2) or hypoxia (1% O2), respectively. Subsequently, both normal and thioacetamide-induced hepatotoxic hepatocytes were treated with NCM or HCM. In addition, partially hepatectomized mice were infused with control saline, NCM, and HCM. The effects on liver regeneration and serum transaminases levels were then compared. RESULTS: Hypoxic preconditioning significantly increased mRNA expression of proinflammatory cytokines (interleukin-6 and tumor necrosis factor-α) and growth factors (hepatocyte growth factor and vascular endothelial growth factor). In both normal and thioacetamide-induced hepatotoxic hepatocyte (alpha mouse liver 12 [AML12]) cell lines, HCM treatment resulted in the highest cell viability (122% and 95%, respectively), followed by NCM (111% and 78%, respectively). In addition, intravenous administration of HCM to partially hepatectomized mice resulted in substantially enhanced liver regeneration compared with the NCM group (P<0.05). CONCLUSIONS: Taken together, the secretome obtained from ASC with hypoxic preconditioning showed potential to alleviate liver damage both in vitro and in vivo. Hypoxic culture of ASC is expected to play an important role in regenerative medicine by inducing secretome production that is beneficial for improving liver regeneration.

Lack of Correlation between Dynamic Balance and Hamstring-to-Quadriceps Ratio in Patients with Chronic Anterior Cruciate Ligament Tears

PURPOSE: The purpose of this study was to evaluate the quadriceps and hamstring muscle strength and hamstring-to-quadriceps (HQ) ratio, as well as the relationships of these parameters with dynamic balance, in patients with anterior cruciate ligament (ACL) rupture. MATERIALS AND METHODS: We compared 25 patients diagnosed with chronic unilateral ACL tears and 25 age-matched healthy volunteers. The maximal torque of the quadriceps and hamstring and dynamic balance were measured. RESULTS: Although the isokinetic maximal peak torques were about 50% lower in the quadriceps (57%, p<0.001) and hamstring (56%, p=0.001) muscles in the chronic ACL tear group than in the control group, their HQ ratios were similar (56%+/-17% vs. 58%+/-6%, p=0.591). HQ ratio was significantly correlated with anterior-posterior stability index (r=-0.511, p=0.021) and overall stability index (r=-0.476, p=0.034) in control group, but these correlations were not observed in chronic ACL tear group. CONCLUSIONS: Thigh muscle strength was about 50% lower in the chronic ACL tear group than in the control group, but the HQ ratio was similar. The dynamic balance of the knee was not influenced by thigh muscle strength but was influenced by HQ ratio in healthy young individuals. However, HQ ratio was not correlated with dynamic knee balance in chronic ACL tear patients.

Sleep quality in rheumatoid arthritis, and its association with disease activity in a Korean population

BACKGROUND/AIMS: The aim of this study was to compare the sleep quality between rheumatoid arthritis (RA) patients and healthy controls; and to evaluate the relationship between RA disease activity and sleep quality in Korea. METHODS: A total of 130 RA patients and 67 age- and sex-matched healthy controls were enrolled in a comparative study of sleep quality using the Pittsburgh Sleep Quality Index (PSQI). Age, gender, concomitant medication, erythrocyte sedimentation rate, serum C-reactive protein, Beck Depression Inventory second edition (BDI-II), 28 joints disease activity score (DAS28), pain visual analog scale (VAS), and PSQI were analyzed as covariates. We also analyzed the sleep quality of RA patients according to the disease activity (DAS28 or = 5.1, respectively). RESULTS: The total PSQI score and the frequency of poor sleep quality, were higher in the RA patients (5.62 +/- 4.19, 38.5%) than in the control subjects (3.57 +/- 2.17, 13.4%). The patients with poor sleep quality (PSQI > 5) were older and had a higher BDI-II and VAS score than the patients without sleep disturbance (PSQI < or = 5). The score in subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbance, daytime dysfunction, total PSQI, and frequency of poor sleep quality were increased when RA activity was high. CONCLUSIONS: Sleep disturbance was observed in RA patients (38.5%), and high RA disease activity was associated with poor sleep quality in Korea.