Surface mapping of gastric motor functions using MRI: a comparative study between humans and rats.

The stomach's ability to store, mix, propel, and empty its content requires highly coordinated motor functions. However, current diagnostic tools cannot simultaneously assess these motor processes. This study aimed to use magnetic resonance imaging (MRI) to map multifaceted gastric motor functions, including accommodation, tonic and peristaltic contractions, and emptying, through a single noninvasive experiment for both humans and rats. Ten humans and 10 Sprague-Dawley rats consumed MRI-visible semisolid meals and underwent MRI scans. We used a surface model to analyze MRI data, capturing the deformation of the stomach wall on ingestion or during digestion. We inferred muscle activity, mapped motor processes, parcellated the stomach into functional regions, and revealed cross-species distinctions. In humans, both the fundus and antrum distended postmeal, followed by sustained tonic contractions to regulate intragastric pressure. Peristaltic contractions initiated from the distal fundus, including three concurrent wavefronts oscillating at 3.3 cycles/min and traveling at 1.7 to 2.9 mm/s. These motor functions facilitated linear gastric emptying with a 61-min half-time. In contrast, rats exhibited peristalsis from the midcorpus, showing two wavefronts oscillating at 5.0 cycles/min and traveling at 0.4 to 0.9 mm/s. For both species, motility features allowed functional parcellation of the stomach along a midcorpus division. This study maps region- and species-specific gastric motor functions. We demonstrate the value of MRI with surface modeling in understanding gastric physiology and its potential to become a new standard for clinical and preclinical investigations of gastric disorders at both individual and group levels.NEW & NOTEWORTHY A novel MRI technique can visualize how the stomach accommodates, mixes, and propels food for digestion in humans and animals alike. Digital models of gastric MRI reveal the functional maps, organization, and distinction of the stomach across individuals and species. This technique holds the unique potential to advance basic and clinical studies of functional gastric disorders.

Human Eyes-Inspired Recurrent Neural Networks Are More Robust Against Adversarial Noises.

Humans actively observe the visual surroundings by focusing on salient objects and ignoring trivial details. However, computer vision models based on convolutional neural networks (CNN) often analyze visual input all at once through a single feedforward pass. In this study, we designed a dual-stream vision model inspired by the human brain. This model features retina-like input layers and includes two streams: one determining the next point of focus (the fixation), while the other interprets the visuals surrounding the fixation. Trained on image recognition, this model examines an image through a sequence of fixations, each time focusing on different parts, thereby progressively building a representation of the image. We evaluated this model against various benchmarks in terms of object recognition, gaze behavior, and adversarial robustness. Our findings suggest that the model can attend and gaze in ways similar to humans without being explicitly trained to mimic human attention and that the model can enhance robustness against adversarial attacks due to its retinal sampling and recurrent processing. In particular, the model can correct its perceptual errors by taking more glances, setting itself apart from all feedforward-only models. In conclusion, the interactions of retinal sampling, eye movement, and recurrent dynamics are important to human-like visual exploration and inference.

Representation learning of resting state fMRI with variational autoencoder.

Resting state functional magnetic resonance imaging (rsfMRI) data exhibits complex but structured patterns. However, the underlying origins are unclear and entangled in rsfMRI data. Here we establish a variational auto-encoder, as a generative model trainable with unsupervised learning, to disentangle the unknown sources of rsfMRI activity. After being trained with large data from the Human Connectome Project, the model has learned to represent and generate patterns of cortical activity and connectivity using latent variables. The latent representation and its trajectory represent the spatiotemporal characteristics of rsfMRI activity. The latent variables reflect the principal gradients of the latent trajectory and drive activity changes in cortical networks. Representational geometry captured as covariance or correlation between latent variables, rather than cortical connectivity, can be used as a more reliable feature to accurately identify subjects from a large group, even if only a short period of data is available in each subject. Our results demonstrate that VAE is a valuable addition to existing tools, particularly suited for unsupervised representation learning of resting state fMRI activity.

Decreases in Concentrations and Human Dietary Intakes of Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in Korean Seafood Between 2005 and 2017.

Concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in 23 seafood species widely consumed by the Korean population in the periods of 2005-2007, 2010-2011, and 2015-2017. The Σ82PCB (sum of 82 PCB congeners) and Σ19PBDE (sum of 19 PBDE congeners) concentrations in the seafood samples of 2015-2017 were 0.06-6.69 ng/g wet weight and 0.01-1.60 ng/g wet weight, respectively. The Σ82PCB and Σ19PBDE concentrations in the samples were significantly correlated. Elevated PCB and PBDE concentrations were found in fatty fish, such as herring, mackerel, and tuna. The current human intakes of PCBs and PBDEs were much lower than the tolerable daily intake or lowest observed adverse effect level. The levels and human dietary intakes of PCBs and PBDEs in the 2015-2017 survey showed decreases of 17-73% and 57-86%, respectively, compared with those in 2005-2007 and 2010-2011 surveys. This indicates that global bans on PCBs and PBDEs have been effective, and their levels and human exposure to them have been gradually declining.

An improved rapid analytical method for the arsenic speciation analysis of marine environmental samples using high-performance liquid chromatography/inductively coupled plasma mass spectrometry.

Arsenic contamination in marine environments is a serious issue because some arsenicals are very toxic, increasing the health risks associated with the consumption of marine products. This study describes the development of an improved rapid method for the quantification of arsenic species, including arsenite (AsIII), arsenate (AsV), arsenocholine (AsC), arsenobetaine (AsB), dimethylarsinic acid (DMA), and monomethyl arsonic acid (MMA), in seaweed, sediment, and seawater samples using high-performance liquid chromatography/inductively coupled plasma-mass spectrometry (HPLC/ICP-MS). ICP-MS based on dynamic reaction cells was used to eliminate spectral interference. Ammonium nitrate- and phosphate-based eluents were used as the mobile phases for HPLC analysis, leading to shorter overall retention time (6 min) and improved peak separation. Arsenicals were extracted with a 1% HNO3 solution that required no clean-up process and exhibited reasonable sensitivity and peak resolution. The optimized method was verified by applying it to hijiki seaweed certified reference material (CRM, NMIJ 7405-a) and to spiked blank samples of sediment and seawater. The proposed method measured the concentration of AsV in the CRM as 9.6 ± 0.6 µg/kg dry weight (dw), which is close to the certified concentration (10.1 ± 0.5 µg/kg dw). The recovery of the six arsenicals was 87-113% for the sediment and 99-101% for the seawater. In the analysis of real samples, AsV was the most abundant arsenical in hijiki and gulfweed, whereas AsB was dominant in other seaweed species. The two inorganic arsenicals (AsIII and AsV) and AsV were the most dominant in the sediment and seawater samples, respectively.

Predictive Coding for Dynamic Visual Processing: Development of Functional Hierarchy in a Multiple Spatiotemporal Scales RNN Model.

This letter proposes a novel predictive coding type neural network model, the predictive multiple spatiotemporal scales recurrent neural network (P-MSTRNN). The P-MSTRNN learns to predict visually perceived human whole-body cyclic movement patterns by exploiting multiscale spatiotemporal constraints imposed on network dynamics by using differently sized receptive fields as well as different time constant values for each layer. After learning, the network can imitate target movement patterns by inferring or recognizing corresponding intentions by means of the regression of prediction error. Results show that the network can develop a functional hierarchy by developing a different type of dynamic structure at each layer. The letter examines how model performance during pattern generation, as well as predictive imitation, varies depending on the stage of learning. The number of limit cycle attractors corresponding to target movement patterns increases as learning proceeds. Transient dynamics developing early in the learning process successfully perform pattern generation and predictive imitation tasks. The letter concludes that exploitation of transient dynamics facilitates successful task performance during early learning periods.

Effects of the ammonium loading rate on nitrite-oxidizing activity during nitrification at a high dose of inorganic carbon.

In this study, the effects of the ammonium loading rate (ALR) and inorganic carbon loading rate (ILR) on the nitrification performance and composition of a nitrifying bacterial community were investigated in a moving bed biofilm reactor, using poly(vinyl alcohol) (PVA) sponge cubes as a supporting carrier. Between the two ALRs of 0.36 and 2.16 kg-N m-1 d-1, stable partial nitritation was achieved at the higher ALR. Inorganic carbon was dosed at high levels: 33.1, 22.0, 16.4, 11.0, and 5.4 times the theoretical amount. Nonetheless, nitrification efficiency was not affected by the ILR at the two ALRs. Quantitative PCR analysis of ammonia- and nitrite-oxidizing bacteria revealed that ALR is an important determinant of partial nitritation by accumulating ammonia-oxidizing bacteria in the nitrification system. In comparison, two nitrite-oxidizing bacterial genera (Nitrobacter and Nitrospira) showed almost the same relative abundance at various ALRs and ILRs. Terminal restriction fragment length polymorphism targeting the gene of ammonia monooxygenase subunit A revealed that Nitrosomonas europaea dominated under all conditions.

Efficacy and safety of fermented garlic extract on hepatic function in adults with elevated serum gamma-glutamyl transpeptidase levels: a double-blind, randomized, placebo-controlled trial.

PURPOSE: Alcoholic liver disease or non-alcoholic fatty liver disease/non-alcoholic steatohepatitis are well-known risk factors for liver fibrosis or cirrhosis and hepatocellular carcinoma; it is a major global health concern, but there are few effective and safe management options. Therefore, we aimed to investigate the effects of fermented garlic extracts (FGEs) on hepatic function in adults with mild hepatic dysfunction without underlying hepatic disease. METHODS: In this double-blind, randomized, placebo-controlled study, seventy-five adults with elevated serum gamma-glutamyl transpeptidase (GGT) levels were included in a FGE-administered group (n = 36) or a placebo group (n = 39), and received either two sachets/day containing FGEs or placebo over a 12-week period. Primary endpoint was the change in serum GGT levels. Data were analysed using a generalized linear mixed effects model. RESULTS: Significant group × time interactions for serum levels of GGT (F = 3.98, P = 0.022) and alanine aminotransferase (ALT; F = 3.28, P = 0.043) were observed with an improvement in levels of GGT (P = 0.066) and ALT (P = 0.014) in the FGE group compared to that reported for the placebo group at the 12-week visits. There was no intergroup difference in the prevalence of adverse events. CONCLUSIONS: Intake of FGEs improved serum GGT and ALT levels in adults with mildly elevated serum GGT level without reported adverse side effects. FGEs might be effective and safe management options for mild hepatic dysfunction.

Utility of obesity indicators for metabolically healthy obesity: an observational study using the Korean National Health and Nutrition Examination Survey (2009-2010).

BACKGROUND: Obese individuals who are not at an elevated risk for cardiovascular disease are described as having metabolically healthy obesity (MHO). We sought to identify clinically useful indicators of MHO. METHODS: Records of the Korean National Health and Nutrition Examination Survey (2009-2010) were used to analyze 3,770 obese subjects (body mass index ≥ 25 kg/m2), who were divided into metabolic syndrome and MHO groups. Persons who met less than 3 of the criteria of metabolic syndrome (MS) were defined as having MHO. We estimated age-specific prevalence rates according to the number of MS criteria that were satisfied (patients meeting 0, ≤1, and ≤2 criteria of MS). Receiver operating characteristic analysis was performed to identify the best indicators of MHO. RESULTS: The prevalence of MHO among obese patients decreased with age. When MHO was defined by the fulfillment of ≤2 criteria of MS, the areas under the curves (AUC) for waist circumference and waist-to-height ratio were 0.743 and 0.747 in men and 0.712 and 0.741 in women, respectively. Waist circumference and waist-to-height ratio were the most accurate predictors of MHO for all investigated definitions. CONCLUSIONS: Waist circumference and waist-to-height ratio provide useful indicators for diagnosing MHO, and are more accurate than body mass index, fat percentage, or weight-adjusted appendicular skeletal muscle mass in the Korean population.

Magnetic Resonance Imaging of Gastric Motility in Conscious Rats.

Introduction: Gastrointestinal (GI) magnetic resonance imaging (MRI) can simultaneously capture gastric peristalsis, emptying, and intestinal filling and transit. Performing GI MRI with animals requires anesthesia, which complicates physiology and confounds interpretation and translation from animals to humans. This study aims to enable MRI in conscious rats, and for the first time, characterize GI motor functions in awake versus anesthetized conditions. Methods: We acclimated rats to remain awake, still, and minimally stressed during MRI. We scanned 14 Sprague-Dawley rats in both awake and anesthetized conditions after voluntarily consuming a contrast-enhanced test meal. Results: Awake rats remained physiologically stable during MRI, showed gastric emptying of 23.7±1.4% after 48 minutes, and exhibited strong peristaltic contractions propagating through the antrum with a velocity of 0.72±0.04 mm/s, a relative amplitude of 40.7±2.3%, and a frequency of 5.1±0.1 cycles per minute. In the anesthetized condition, gastric emptying was about half of that in the awake condition, likely due to the effect of anesthesia in halving the amplitudes of peristaltic contractions rather than their frequency (not significantly changed) or velocity. In awake rats, the intestine filled more quickly and propulsive contractions were more occlusive. Conclusion: We demonstrated the effective acquisition and analysis of GI MRI in awake rats. Awake rats show faster gastric emptying, stronger gastric contraction with a faster propagation speed, and more effective intestinal filling and transit, compared to anesthetized rats. Our protocol is expected to benefit future preclinical studies of GI physiology and pathophysiology.

Gender differences in the relationship between vitamin C and abdominal obesity.

BACKGROUND: Vitamin C is a commonly used antioxidant supplement; however, its effects on obesity and fat distribution are equivocal. We examined nationally representative data to determine whether intake of vitamin C is related to abdominal obesity. METHODS: In total, 16,414 adults (58 % women) from the 2007 - 2010 Korea National Health and Nutrition Examination Survey were included in the analysis. Vitamin C intake was calculated using 24-hour recalls and categorized into quintiles. The multivariate models in logistic regression analysis were adjusted for age, energy intake, sodium intake, smoking, alcohol consumption, physical activity, education, income, pre-existing disease conditions, survey year, and menopausal status (in women only). RESULTS: Compared with the lowest quintile (Q1) of vitamin C intake, the adjusted odds ratios of Q2, Q3, Q4, and Q5 for abdominal adiposity were 0.92, 0.86, 0.81, and 0.70, respectively, in women (p for trend = 0.0007). This association was maintained after adjusting for the confounding factors; however, we observed no association between intake of vitamin C and abdominal obesity in men. CONCLUSIONS: Vitamin C intake showed a negative association with abdominal obesity in women. Further research is warranted on the association between and the mechanism of vitamin C in abdominal obesity.

Temporal trends (2004-2009) of imposex in rock shells Thais clavigera collected along the Korean coast associated with tributyltin regulation in 2003 and 2008.

We investigated the temporal trend in contamination of butyltin compounds (BTs) along the Korean coast using imposex and tributyltin (TBT) burden in gastropods (Thais clavigera) as a biomonitor. Thais clavigera were collected from 26 locations with different shipping activities between 2004 and 2009 after restrictions on TBT-based antifouling paints were imposed in Korea. In the present study, imposex indices and TBT tissue concentrations significantly decreased over time from 2004 to 2009, confirming the effectiveness of TBT regulation. However, imposex in 2009 samples was still found. Significantly high imposex indices and TBT tissue residues were found in large ports containing commercial and ferry services compared with small ports and background areas. Imposex indices in background areas had decreased to zero, suggesting recovery from imposex caused by BT contamination. These results suggest that recovery from TBT contamination occurs faster in areas with very low maritime activities than areas with high maritime activities.

Pharmacokinetic and pharmacodynamic drug-drug interactions between evogliptin and empagliflozin or dapagliflozin in healthy male volunteers.

Evogliptin (EV) is a novel dipeptidyl peptidase-4 inhibitor (DPP4i) for glycemic control in patients with type 2 diabetes mellitus (T2DM). This study evaluated the pharmacokinetic (PK) and pharmacodynamic (PD) interactions between EV and sodium glucose cotransporter-2 inhibitors (SGLT2i) in healthy volunteers since combination therapy of DPP4i and SGLT2i has been considered as an effective option for T2DM treatment. A randomized, open-label, multiple-dose, two-arm, three-period, three treatments, two-sequence crossover study was conducted in healthy Korean volunteers. In arm 1, subjects were administered 5 mg of EV once daily for 7 days, 25 mg of empagliflozin (EP) once daily for 5 days, and the combination once daily for 5 days (EV + EP). In arm 2, subjects were administered 5 mg of EV once daily for 7 days, 10 mg of dapagliflozin (DP) once daily for 5 days, and the combination once daily for 5 days (EV + DP). Serial blood samples were collected for PK analysis, and oral glucose tolerance tests were conducted for PD analysis. In each arm, a total of 18 subjects completed the study. All adverse events (AEs) were mild with no serious AEs. The geometric mean ratio and confidence interval of the main PK parameters (maximum concentration of the drug in plasma at steady state and area under the plasma drug concentration-time curve within a dosing interval at a steady state) between EV and either EP or DP alone were not significantly altered by co-administration. Administration of EV + EP or EV + DP did not result in significant PD changes, as determined by the glucose-lowering effect. Administration of EV + EP or EV + DP had no significant effects on the PK profiles of each drug. All treatments were well-tolerated.

Novel LC-MS/MS analysis of the GLP-1 analog semaglutide with its application to pharmacokinetics and brain distribution studies in rats.

Semaglutide, one of the most potent glucagon-like peptide (GLP)-1 analogs, has widely been used to treat type II diabetes mellitus and obesity. Recent studies have shown that semaglutide also works on the brain, suggesting its potential utility for various diseases, including Parkinson's disease and Alzheimer's disease. This study aimed to develop a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of semaglutide in both plasma and brain to characterize the pharmacokinetics and brain distribution in rats. Semaglutide was extracted by simple protein precipitation with methanol from plasma and by solid phase extraction from brain tissue. Liraglutide was used as an internal standard. Gradient elution profiles with mobile phases comprising 0.1 % formic acid in water and acetonitrile were used for chromatographic separation. The lower limit of quantification (LLOQ) of the LC-MS/MS assay was 0.5 ng/mL for both rat plasma and brain. Intra- and inter-day accuracy ranged 89.20-109.50 % in the plasma and 92.00-105.00 % in the brain. Precision was within 8.92 % in the plasma and 7.94 % in the brain. Sprague-Dawley rats were given semaglutide by intravenous (IV, 0.02 mg/kg) and subcutaneous (SC, 0.1 and 0.2 mg/kg) injection. Plasma concentrations of semaglutide showed a multi-exponential decline with an average half-life of 7.22-9.26 hr in rats. The subcutaneous bioavailability of semaglutide was 76.65-82.85 %. The brain tissue to plasma partition coefficient (Kp) value of semaglutide was estimated as <0.01. Among the different regions of the brain, semaglutide concentrations were significantly higher in the hypothalamus. The analytical method and pharmacokinetic information may be helpful toward a better understanding of the effect of semaglutide in the brain and further development of GLP-1 analogs for various brain diseases.

Diffeomorphic Surface Modeling for MRI-Based Characterization of Gastric Anatomy and Motility.

OBJECTIVE: Gastrointestinal magnetic resonance imaging (MRI) provides rich spatiotemporal data about the movement of the food inside the stomach, but does not directly report muscular activity on the stomach wall. Here we describe a novel approach to characterize the motility of the stomach wall that drives the volumetric changes of the ingesta. METHODS: A neural ordinary differential equation was optimized to model a diffeomorphic flow that ascribed the deformation of the stomach wall to a continuous biomechanical process. Driven by this diffeomorphic flow, the surface of the stomach progressively changes its shape over time, while preserving its topology and manifoldness. RESULTS: We tested this approach with MRI data collected from 10 rats under a lightly anesthetized condition, and demonstrated accurate characterization of gastric motor events with an error in the order of sub-millimeters. Uniquely, we characterized gastric anatomy and motility with a surface coordinate system common at both individual and group levels. Functional maps were generated to reveal the spatial, temporal, and spectral characteristics of muscle activity and its coordination across different regions. The peristalsis at the distal antrum had a dominant frequency and peak-to-peak amplitude of [Formula: see text] cycles per minute and [Formula: see text] mm, respectively. The relationship between muscle thickness and gastric motility was found to be distinct between two functional regions in the proximal and distal stomach. CONCLUSION: These results demonstrate the efficacy of using MRI to model gastric anatomy and function. SIGNIFICANCE: The proposed approach is expected to enable non-invasive and accurate mapping of gastric motility for preclinical and clinical studies.

Weekend catch-up sleep is associated with decreased risk of being overweight among fifth-grade students with short sleep duration.

Previous studies have reported a relationship between short sleep duration and childhood overweight. Although school-aged children tend to compensate for weekday sleep deficit by increasing weekend sleep duration, the association between weekend catch-up sleep and childhood overweight remains unclear. This study aimed to examine the relationship between weekend catch-up sleep and being overweight in children. A total of 936 school children (48.2% boys) aged 10 or 11 years participated in this school-based cohort study. Anthropometric measurements including height and body weight were carried out. We obtained data on sleep patterns, lifestyle and parent characteristics using questionnaires. The main outcome measure was childhood overweight. After adjusting for the relevant confounding variables (age, sex, breakfast eating, screen time and parental obesity), longer sleep on weekdays and weekends was associated with decreased odds of childhood overweight (OR: 0.68; 95% CI: 0.54-0.86; OR: 0.64; 95% CI: 0.53-0.77, respectively). Participants with increased catch-up sleep duration during weekends also had decreased odds of being overweight (OR: 0.67; 95% CI: 0.53-0.85). There was an interaction between weekday sleep duration and weekend catch-up sleep in relation to childhood overweight, and this effect of weekend catch-up sleep on being overweight was stronger as the participants slept less on weekdays (P = 0.024). These results indicate that weekend catch-up sleep is independently associated with decreased risk of being overweight in fifth-grade students, and this effect can be varied by the weekday sleep duration. A prospective study is required to confirm this observation.

Intake and potential health risk of butyltin compounds from seafood consumption in Korea.

Concentrations of butyltin compounds (BTs) were determined in 47 species of seafood commonly consumed in Korea to investigate intakes of BTs from seafood consumption and the potential health risks to the Korean population. The concentrations of BTs (the sum of dibutyltin and tributyltin) in seafood ranged from less than the limit of detection to 96.3 ng/g wet weight, which are levels similar to those reported for other countries. The intake of BTs from seafood consumption by the general population was estimated to be 17.2 ng/kg body weight/day. Fish accounted for 50% of the total intakes of BT, and the next contributor was cephalopods (26%). The estimated intakes for males and females were 18.6 and 15.7 ng/ kg body weight/day, respectively. Among the age groups investigated, children (<2 years and 3-6 years) had higher intakes of BTs compared with adults. The estimated intake of BTs for Korean population groups was 5-8% of the tolerable daily intake of 250 ng/ kg body weight/day set by the European Food Safety Authority. Our results suggest that the Korean population is not expected to exceed the threshold value for adverse health effects.

Polybrominated diphenyl ethers, polychlorinated biphenyls, and organochlorine pesticides in adipose tissues of Korean women.

Studies on residue levels and accumulation profiles of persistent organic pollutants (POPs) in human adipose tissues of Korean populations are scarce. In this study, concentrations and accumulation features of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) were measured in adipose tissues of Korean women age 40-68 years. The highest concentrations were found for PCBs and DDTs, which were 1-2 orders of magnitude greater than the concentrations of hexachlorocyclohexanes, chlordanes, and PBDEs. The concentrations of PCBs and OCPs were lower than those reported for other countries. However, PBDE concentrations were greater than those reported for other countries, suggesting that ongoing exposure to PBDEs is a concern in Korea. The profiles of PBDEs were characterized by the predominance of BDE 209, followed by nona- and octa-BDEs, which are consistent with the consumption patterns of products containing PBDEs in Korea. The concentrations of PCBs and some OCPs were significantly correlated with each other, whereas PBDEs showed low or moderate correlations with other POPs, suggesting differences in exposure routes and biotransformation potentials of the compounds studied. The concentrations of organochlorines and PBDEs were not correlated with subjects' age and body mass index. The results of this study provide baseline information on POPs in adipose tissues of the general population in Korea.

Exposure assessment for methyl and total mercury from seafood consumption in Korea, 2005 to 2008.

Reports on the occurrence and intake assessment of mercury for Korean seafood are currently not available. This is the first report to estimate the intake of methyl (Me-Hg) and total mercury (T-Hg) from seafood consumption in Korea. The concentrations of Me-Hg and T-Hg in seafood ranged from 1.02 to 780 (mean: 55.6) ng g(-1) wet weight and 4.89 to 1008 (mean: 100) ng g(-1) wet weight, respectively. The residue levels of Me-Hg and T-Hg in Korean seafood were moderate compared with those found in other countries. The methylation ratios of fish, cephalopods and crustaceans were similar, but shellfish had lower values compared with other species. The intakes of Me-Hg and T-Hg from seafood consumption for the general population were estimated to be 38.8 and 73.8 ng kg(-1) body weight per day, respectively. Mackerel, tuna and squid made the highest contributions to the total intake of these contaminants. Among eight age groups, 30-49 year and 3-6 year age groups had the highest exposure to Me-Hg and T-Hg. The concentrations and intakes of Me-Hg and T-Hg from Korean seafood were less than the allowable residue levels and threshold intake levels suggested by Korean and international authorities. The present study may be useful for risk management of mercury in Korean seafood.