Herein, we report the pathogenic and phylogenetic characteristics of seven Shiga toxin (Stx)-producing Escherichia coli (STEC) isolates from 434 retail meats collected in Korea during 2006 to 2012. The experimental analyses revealed that all isolates (i) were identified as non-O157 STEC, including O91:H14 (3 isolates), O121:H10 (2 isolates), O91:H21 (1 isolate), and O18:H20 (1 isolate), (ii) carried diverse Stx subtype genes (stx₁, stx(2c), stx(2e), or stx₁ + stx(2b)) whose expression levels varied strain by strain, and (iii) lacked the locus of enterocyte effacement (LEE) pathogenicity island, a major virulence factor of STEC, but they possessed one or more alternative virulence genes encoding cytotoxins (Cdt and SubAB) and/or adhesins (Saa, Iha, and EcpA). Notably, a significant heterogeneity in glutamate-induced acid resistance was observed among the STEC isolates (p < 0.05). In addition, phylogenetic analyses demonstrated that all three STEC O91:H14 isolates were categorized into sequence type (ST) 33, of which two beef isolates were identical in their pulsotypes. Similar results were observed with two O121:H10 pork isolates (ST641; 88.2% similarity). Interestingly, 96.0% of the 100 human STEC isolates collected in Korea during 2003 to 2014 were serotyped as O91:H14, and the ST33 lineage was confirmed in approximately 72.2% (13/18 isolates) of human STEC O91:H14 isolates from diarrheal patients.
Cytotoxins ; Enterocytes ; Escherichia coli ; Genomic Islands ; Humans ; Korea ; Meat ; Population Characteristics ; Red Meat ; Shiga Toxin ; Shiga-Toxigenic Escherichia coli ; Virulence ; Virulence Factors

BACKGROUND/AIMS: Although pyogenic liver abscesses (PLAs) can be successfully treated, the visual prognosis of patients with endogenous endophthalmitis (EE) associated with a PLA is poor. Early diagnosis and prompt intervention may salvage useful vision. Therefore, we investigated risk factors for EE in patients with PLA, to facilitate early diagnosis. METHODS: Data from 626 patients diagnosed with PLA between January 2004 and July 2013 were analyzed retrospectively. Patients were divided into two groups: those with liver abscess-associated endogenous endophthalmitis (LAEE) and non-LAEE. RESULTS: The prevalence of EE in PLA patients was 1.92%. The mean age for all patients (373 males, 59.6%) was 62.8 years. Upon multivariate logistic regression, a liver abscess or another systemic infection (odds ratio [OR], 5.52; p = 0.005), an abscess in the right superior segment (OR, 5.26; p = 0.035), and Klebsiella pneumoniae infection (OR, 3.68; p = 0.039), were risk factors for LAEE. The final visual outcomes of patients with LAEE included no light perception in seven, hand motion only in three, and decreased visual acuity in two. Vitrectomy and early intravitreal injections of antibiotics improved visual acuity and preserved useful vision. CONCLUSIONS: PLA patients with other systemic infections, abscesses in the right superior segment, and K. pneumoniae infection require close monitoring and early intervention to treat LAEE. Intravitreal antibiotic injections or early vitrectomy may salvage useful vision.
Aged ; Anti-Bacterial Agents/administration & dosage ; Chi-Square Distribution ; Early Diagnosis ; Endophthalmitis/diagnosis/*epidemiology/microbiology/therapy ; Female ; Humans ; Intravitreal Injections ; Liver Abscess, Pyogenic/diagnosis/*epidemiology/microbiology ; Logistic Models ; Male ; Middle Aged ; Multivariate Analysis ; Odds Ratio ; Predictive Value of Tests ; Prevalence ; Republic of Korea/epidemiology ; Retrospective Studies ; Risk Factors ; Tomography, X-Ray Computed ; Treatment Outcome ; Visual Acuity ; Vitrectomy

OBJECTIVE: Genetic imaging is used to investigate the mechanism by which genetic variants influence brain structure. In a previous study, a structural change of the dorsolateral prefrontal cortex was associated with symptom modulation in post-traumatic stress disorder patients. This study examined the effect of a polymorphism in the gene encoding brain-derived neurotrophic factor (BDNF) on regional gray matter (GM) volumes and the correlations between the dorsolateral prefrontal GM volume and the stress level in healthy volunteers. METHODS: Sixty-one volunteers underwent genotyping for the BDNF Val66Met single nucleotide polymorphism (SNP) and completed the Stress Response Inventory (SRI). Magnetic resonance images were also acquired, and the effect of each subject's BDNF genotype and SRI subscore on his or her dorsolateral prefrontal GM volume was evaluated. RESULTS: The Val/Val homozygotes had significantly larger GM volumes in the prefrontal cortex and the precuneus, the uncus, and the superior temporal and occipital cortices than Met carriers. The Met homozygotes demonstrated a higher stress response in depression domain than Val/Val and Val/Met groups. A negative correlation between the middle frontal cortex GM volume and the SRI depression subscore was found. CONCLUSION: These findings indicate an interaction between genes and brain structure, and they suggest that differences in dorsolateral prefrontal GM volume related to the BDNF Val66Met SNP are associated with resilience to stressful life events, particularly in the dimension of emotion.
Brain ; Brain-Derived Neurotrophic Factor ; Depression ; Genotype ; Homozygote ; Humans ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Prefrontal Cortex ; Stress Disorders, Post-Traumatic

OBJECTIVE: The functional strategic mechanisms in the brain during performing visuospatial working memory tasks, especially tasks with heavy load, are controversial. We conducted the functional magnetic resonance imaging (fMRI) while sixteen subjects were performing face- and location-matching n-back tasks to examine causal relations within the frontoparietal networks. METHODS: We applied a sophisticated method, the structural equation modeling (SEM), to the fMRI data. The imaging data were analyzed by extracting the task-related eigenseries using the principal component analysis (PCA) and then by applying a form of data-driven model called the automated search method. RESULTS: The SEM analyses revealed a functional shift of network connectivity from the right to the left hemisphere with increasing load in the face-matching n-back tasks while the location-matching tasks required bilateral activation. In the locating matching n-back tasks, a pattern of parallel processing was observed in the left phonological loop and the right inferior parietal regions. Furthermore, object working memory-related activities in the left hemisphere reliably contributed to performance of both the face- and location-matching 2-back tasks. CONCLUSION: Our results are consistent with previous reports in terms of demonstrating parallel and distributed information processing during performing working memory tasks with heavy loads. Our results additionally suggest a dynamic shift between the fast imagery circuit (right hemisphere) and the stable verbal circuit (left hemisphere), depending on task load.
Automatic Data Processing ; Brain ; Magnetic Resonance Imaging ; Memory, Short-Term ; Principal Component Analysis

Recent studies have reported that cognitive inflexibility associated with impairments in a frontal-striatal circuit and parietal region is a core cognitive deficit of obsessive-compulsive disorder (OCD). However, few studies have examined progressive changes in these regions following clinical improvement in obsessive-compulsive symptoms. To determine if treatment changes the aberrant activation pattern associated with task switching in OCD, we examined the activation patterns in brain areas after treatment. The study was conducted on 10 unmedicated OCD patients and 20 matched controls using event-related functional magnetic resonance imaging. Treatment improved the clinical symptoms measured by the Yale-Brown Obsessive Compulsive Scale and behavioral flexibility indicated by the switching cost. At baseline, OCD showed significantly less activation in the dorsal and ventral frontal-striatal circuit and parietal regions under the task-switch minus task-repeat condition compared with controls. After treatment, the neural responses in the ventral frontal-striatal circuit in OCD were partially normalized, whereas the activation deficit in dorsal frontoparietal regions that mediate shifting attention or behavioral flexibility persisted. It is suggested that altered brain activation in ventral frontal-striatal regions in OCD patients is associated with their cognitive flexibility and changes in these regions may underlie the pathophysiology of OCD.
Adult ; Basal Ganglia/*metabolism ; Behavioral Symptoms/drug therapy ; Female ; Frontal Lobe/*drug effects/physiopathology ; Humans ; Magnetic Resonance Imaging ; Male ; Obsessive-Compulsive Disorder/*drug therapy/physiopathology ; Parietal Lobe/*drug effects/physiopathology

OBJECTIVE: Recent neuroimaging studies have suggested that brain changes occur in subjects at ultra-high risk (UHR) for psychosis while experiencing prodromal symptoms, among which depression may increase the risk of developing a psychotic disorder. The goal of this study is to examine brain metabolite levels in the anterior cingulate cortex, the left dorsolateral prefrontal cortex and the left thalamus in subjects at UHR for psychosis and to compare brain metabolite levels between the UHR subjects with comorbid major depressive disorder and healthy controls. METHODS: Proton magnetic resonance spectroscopy was used to examine brain metabolite levels. Twenty UHR subjects and 20 age- and intelligence quotient (IQ)-matched healthy controls were included in this study. RESULTS: Overall, no significant differences were observed in any metabolite between the UHR and healthy control group. However, UHR subjects with major depressive disorder showed significantly higher myo-inositol (Ins) levels in the left thalamus, compared to the healthy control. CONCLUSION: Our results demonstrate that increased thalamic Ins level is associated with prodromal depressive symptoms. Further longitudinal follow-up studies with larger UHR sample sizes are required to investigate the function of Ins concentrations as a biomarker of vulnerability to psychosis.
Brain ; Depression ; Depressive Disorder, Major ; Gyrus Cinguli ; Intelligence ; Magnetic Resonance Spectroscopy ; Neuroimaging ; Prefrontal Cortex ; Prodromal Symptoms ; Protons ; Psychotic Disorders ; Sample Size ; Schizophrenia ; Thalamus

OBJECTIVE: Recent neuroimaging studies have suggested that brain changes occur in subjects at ultra-high risk (UHR) for psychosis while experiencing prodromal symptoms, among which depression may increase the risk of developing a psychotic disorder. The goal of this study is to examine brain metabolite levels in the anterior cingulate cortex, the left dorsolateral prefrontal cortex and the left thalamus in subjects at UHR for psychosis and to compare brain metabolite levels between the UHR subjects with comorbid major depressive disorder and healthy controls. METHODS: Proton magnetic resonance spectroscopy was used to examine brain metabolite levels. Twenty UHR subjects and 20 age- and intelligence quotient (IQ)-matched healthy controls were included in this study. RESULTS: Overall, no significant differences were observed in any metabolite between the UHR and healthy control group. However, UHR subjects with major depressive disorder showed significantly higher myo-inositol (Ins) levels in the left thalamus, compared to the healthy control. CONCLUSION: Our results demonstrate that increased thalamic Ins level is associated with prodromal depressive symptoms. Further longitudinal follow-up studies with larger UHR sample sizes are required to investigate the function of Ins concentrations as a biomarker of vulnerability to psychosis.
Brain ; Depression ; Depressive Disorder, Major ; Gyrus Cinguli ; Intelligence ; Magnetic Resonance Spectroscopy ; Neuroimaging ; Prefrontal Cortex ; Prodromal Symptoms ; Protons ; Psychotic Disorders ; Sample Size ; Schizophrenia ; Thalamus

OBJECTIVES: The purpose of this study was to examine structural abnormalities of brain in patients with pathological gambling(PG) using voxel-based morphometry. METHODS: We compared gray matter(GM) volumes between 10 patients with PG and 14 age- and IQmatched healthy controls and examined the relationship of GM volumes with clinical variables in patients with PG. RESULTS: We found significant increase of GM volume in the superior, middle, and inferior frontal gyri, the midbrain, the middle temporal gyrus, the precuneus, and the fusiform gyrus of patients with PG. A significant decrease of GM volume was observed in the parahippocampal gyrus and the lingual gyrus of the patient group. In addition, GM volumes in some of these regions were positively associated with South Oaks Gambling Screen score and negatively with age of onset in patients with PG. CONCLUSION: Current findings indicate that structural abnormalities in the fronto-temporal cortex, the midbrain, and the precuneus might be involved in the pathophysiology of PG, and contribute to some of the behavioral changes observed in patients with PG.
Age of Onset ; Brain ; Gambling ; Humans ; Mesencephalon ; Parahippocampal Gyrus

BACKGROUND: Xenotransplantation in discordant species results in immediate and irreversible hyperacute rejection due to natural antibodies, IgM. With this, antibody depletion is one option to reduce hyperacute rejection, we investigated the effect of PCPP (postcentrifugal plasmapheresis) on the depletion of natural antibodies and the effect of antibody titer on xenograft survival. MATERIAL ANDMETHOD: Outbred swines (n=4) weighing 10~20 kg were used as donors and mongrel dogs (n=4) weighing 25~30 kg were used as recipients. Recipient canines underwent plasmapheresis (COBE TPE Laboratories, Lakewood. CO, USA). Pre-transplantation PCPP was performed on day - 2 and day 0. There were three groups (Group 0: no PCPP, Group 1: 1 pla sma-volume (PV) at day 2 and 2 PV at day 0, Group 2: 2 PV at day - 2 and 2 PV at day 0). A swine heart was heterotopically transplanted into a recipient's abdominal infrarenal aorta and inferior vena cava. Mean percent depletion of total IgM and IgG in plasma of the recipients was calculated. Serum albumin, elecctrolyte, complement activity and coagualtion factors were measured. Histopathologic examination of heart specimens was performed. RESULT: Mean percent depletion of IgM and IgG were 95.7+/-1.2%, 80.5+/-2.4% in the group 2 at the end of PCPP. The percent depletion of serum albumin concentration was decreased from 2.8 to 1.4 g/dL in the group 1 and 3.0 to 1.5 g/dL in the group 2. Complement hemolytic activity was decreased in group 1 and 2, but returned to normal level within 24 hours. Complement hemolytic activity was reduced to 10% of pre-PCPP level in group 2. Serum fibrinogen decreased to 20% or less and was recovered within 24 hours in group 2. Antithrombin III decreased but less than fibrinogen. PT and aPTT were sometimes but not always prolonged during plasmapheresis. After plasmapheresis, PT and aPTT were prolonged beyond the measurable level. D-dimer was not found during PCPP, but appeared and maintained from 10 minutes after transplantation. Graft survival time was 5 min in group 0, and it was 90+/-0 min in the group 2. Histopathologic changes were more typically characterized by edema, hemorrhages, thrombosis in all groups at the end of experiment. CONCLUSION: PCPP effectively removed immuoglobulins and reduced the titer of natural antibodies, as a result, significantly prololonged swine heart xenograft survival.
Animals ; Antibodies ; Antithrombin III ; Aorta ; Complement System Proteins ; Dogs ; Edema ; Fibrinogen ; Graft Rejection ; Graft Survival ; Heart ; Hemorrhage ; Heterografts* ; Humans ; Immunoglobulin G ; Immunoglobulin M ; Models, Animal ; Plasma ; Plasmapheresis ; Serum Albumin ; Swine ; Thrombosis ; Tissue Donors ; Transplantation, Heterologous* ; Vena Cava, Inferior

In diabetic patients who were being treated with hemodialysis, coma and other neurological deficits did not occur in spite of extremely elevated serum glucose levels. In this report, we compared diabetic patients with renal failure in severe hyperglycemia with nonketotic hyperosmolar coma patients with normal renal function to know what affect mental changes. Mental changes were not present in diabetic patients with renal failure. These patients with renal failure showed more severe hyperglycemia, but corrected serum sodium concentration and calculated effective serum osmolality were low. So it is suggested that corrected serum sodium concentration and effective serum osmolality are more important factor affecting mental changes than high blood glucose levels in diabetic patients with renal failure, due to absence of osmotic diuresis.
Blood Glucose ; Coma ; Diuresis ; Humans ; Hyperglycemia* ; Osmolar Concentration ; Renal Dialysis ; Renal Insufficiency* ; Sodium