A Case of Carcinoma with Sebaceous Differentiation arising in the Patient who was Treated with Parotid Gland Adenocarcinoma / 대한두경부종양학회지

Sebaceous carcinoma is extremely rare in the parotid gland. Recently, we experienced a case of carcinoma with sebaceous differentiation arising from the parotid gland in patient who was diagnosed as parotid adenoma carcinoma and underwent total parotidectomy.A 73-year-old male visited our department for the evaluation of 3-month history of infra-auricular mass combined with pain. Radiologic finding showed lobulated enhancing and solid mass with calcification in the right parotid gland. Initially, total parotidectomy with supraomohyoid neck dissection was performed. Pathological findings showed capsulated whitish mass with hemorrhage and cystic degeneration. Immunohistochemically, CK7, CK5/6, p63 were positive and CEA was negative. The intra-operative frozen section diagnosis was mucoepidermoid carcinoma. The permanent diagnosis was changed to adenocarcinoma, NOS(not otherwise specified). Fourteen months later, the newly developed mass was noticed on the operation bed. The mass was clinically diagnosed as recurred adenocarcinoma. Revision parotidectomy was performed and pathological findings revealed that the tumor was newly developed sebaceous carcinoma. We report a case of carcinoma with sebaceous differentiation in parotid gland with a review of literature.

PLGA Microspheres Containing Hydrophobically Modified Magnesium Hydroxide Particles for Acid NeutralizationMediated Anti-Inflammation

BACKGROUND@#Poly(lactic-co-glycolic acid) (PLGA) microspheres have been actively used in various pharmaceutical formulations because they can sustain active pharmaceutical ingredient release and are easy to administer into the body using a syringe. However, the acidic byproducts produced by the decomposition of PLGA cause inflammatory reactions in surrounding tissues, limiting biocompatibility. Magnesium hydroxide (MH), an alkaline ceramic, has attracted attention as a potential additive because it has an acid-neutralizing effect. @*METHODS@#To improve the encapsulation efficiency of hydrophilic MH, the MH particles were capped with hydrophobic ricinoleic acid (RA-MH). PLGA microspheres encapsulated with RA-MH particles were manufactured by the O/W method. To assess the in vitro cytotoxicity of the degradation products of PLGA, MH/PLGA, and RA-MH/PLGA microspheres, CCK-8 and Live/Dead assays were performed with NIH-3T3 cells treated with different concentrations of their degradation products. in vitro anti-inflammatory effect of RA-MH/PLGA microspheres was evaluated with quantitative measurement of pro-inflammatory cytokines. @*RESULTS@#The synthesized RA-MH was encapsulated in PLGA microspheres and displayed more than four times higher loading content than pristine MH. The PLGA microspheres encapsulated with RA-MH had an acid-neutralizing effect better than that of the control group. In an in vitro cell experiment, the degradation products obtained from RA-MH/PLGA microspheres exhibited higher biocompatibility than the degradation products obtained from PLGA microspheres. Additionally, the RA-MH/PLGA microsphere group showed an excellent anti-inflammatory effect. @*CONCLUSION@#Our results proved that RA-MH-encapsulated PLGA microspheres showed excellent biocompatibility with an anti-inflammatory effect. This technology can be applied to drug delivery and tissue engineering to treat various incurable diseases in the future.

Feasibility of Intraoperative Parathyroid Hormone Monitoring in Minimally Invasive Surgery / 대한이비인후과학회지

Background and Objectives@#There has been a long debate on whether intraoperative parathyroid hormone (IOPTH) monitoring is mandatory or not in the excision of a single abnormal parathyroid gland. The aim of this study is to suggest a new criteron of IOPTH monitoring. Subjects and Method We retrospectively analyzed 31 patients who underwent parathyroidectomy from 2005 to 2019. Patients had IOPTH not measured and those with secondary hyperparathyroidism were excluded. IOPTH was measured preoperatively (EX00), at 10 minutes (EX10) and 20 minutes (EX20) after the excision and analyzed. We determined the surgery as a ‘successful excision of lesion (SEOUL)’ when it met the following criteria: criterion 1) the level of EX10 or EX20 decreased under the upper normal or under upper limit of parathyroid hormone (65 pg/mL); criterion 2) EX20 decreased below 50% of EX00 and less than 195 pg/ mL (3 times the upper normal limit); criterion 3) multiglandular disease. @*Results@#Twenty-five patients among 31 patients were included this study (M:F=8:17). Twenty- two patients were suspected of single lesion and three patients of multiple lesions on preoperative images (99mTc-sestamibi scan, neck CT, and PET-CT). IOPTH of EX00, EX10, and EX20 were 488.92±658.74, 121.36±134.73, and 92.44±111.55 pg/mL, respectively. Sixty-four percent patients (16/25) met the criterion 1. Six patients (24%) successfully excised a lesion meeting the criterion 2. Three patients had multiglandular disease, meeting the criterion 3. @*Conclusion@#Our new criteria suggest when we could stop the procedure. If the level of IOPTH does not meet the SEOUL criteria, it means that there might be more lesions.

A Case of Nontuberculous Mycobacterial Infection on Branchial Cleft Cyst / 대한이비인후과학회지

Nontuberculous mycobacteria (NTM) is commonly found in the surrounding environment and can cause opportunistic infection. Mainly, it causes lymph node infection in the cervical area, which is often known to occur in children. Recently, we have experienced a case of NTM infection on a branchial cleft cyst in a 36-year old male. NTM was diagnosed by fine needle aspiration and branchial cleft cyst was confirmed by postoperative pathologic findings. We report this case with a review of literature.

Characteristics and Risk Factors of Recurrent Epistaxis in Geriatric Patients / 대한이비인후과학회지

Background and Objectives@#Recurrent epistaxis requiring emergency department (ED) visits results in increased morbidity in the elderly and associated with high health care costs. This study is to analyze the frequency and characteristics of epistaxis patients in the elderly and to find out the risk factors and effective treatment for recurrent epistaxis. Subjects and Method We studied retrospectively the clinical cases of 977 emergency patients and 155 patients, aged over 65, for the treatment of epistaxis during the last 10 years from January 2008 to January 2018. The group A, comprised of 95 patients (68.29%), was treated with an initial treatment. The group B, which comprised of 60 patients (38.71%), visited for re-bleeding following an initial treatment. @*Results@#Patients made 2 to 10 ED visits due to re-bleeding and 32 of the 60 patients (53.5%) visited twice. The electrocauterization was the most common (61.7%) for treatment method during rebleeding, followed by posterior packing (18.3%). The factors that increases the risk of recurrent epistaxis are anticoagulants, posterior epistaxis, anterior packing, inefficient ED packing. There was no correlation between comorbidities and rebleeding. @*Conclusion@#Accurate medical history taking of anticoagulants may enable personnel to provide more effective management of these patients. The most important factors in the failure of primary care were not being able to find the precise area of bleeding and ineffective packing during the initial treatment. Therefore, it is important that we must carefully check the areas using the endoscope to decrease the failure of initial treatment of epistaxis.

PLGA Microspheres Containing Hydrophobically Modified Magnesium Hydroxide Particles for Acid NeutralizationMediated Anti-Inflammation

BACKGROUND@#Poly(lactic-co-glycolic acid) (PLGA) microspheres have been actively used in various pharmaceutical formulations because they can sustain active pharmaceutical ingredient release and are easy to administer into the body using a syringe. However, the acidic byproducts produced by the decomposition of PLGA cause inflammatory reactions in surrounding tissues, limiting biocompatibility. Magnesium hydroxide (MH), an alkaline ceramic, has attracted attention as a potential additive because it has an acid-neutralizing effect. @*METHODS@#To improve the encapsulation efficiency of hydrophilic MH, the MH particles were capped with hydrophobic ricinoleic acid (RA-MH). PLGA microspheres encapsulated with RA-MH particles were manufactured by the O/W method. To assess the in vitro cytotoxicity of the degradation products of PLGA, MH/PLGA, and RA-MH/PLGA microspheres, CCK-8 and Live/Dead assays were performed with NIH-3T3 cells treated with different concentrations of their degradation products. in vitro anti-inflammatory effect of RA-MH/PLGA microspheres was evaluated with quantitative measurement of pro-inflammatory cytokines. @*RESULTS@#The synthesized RA-MH was encapsulated in PLGA microspheres and displayed more than four times higher loading content than pristine MH. The PLGA microspheres encapsulated with RA-MH had an acid-neutralizing effect better than that of the control group. In an in vitro cell experiment, the degradation products obtained from RA-MH/PLGA microspheres exhibited higher biocompatibility than the degradation products obtained from PLGA microspheres. Additionally, the RA-MH/PLGA microsphere group showed an excellent anti-inflammatory effect. @*CONCLUSION@#Our results proved that RA-MH-encapsulated PLGA microspheres showed excellent biocompatibility with an anti-inflammatory effect. This technology can be applied to drug delivery and tissue engineering to treat various incurable diseases in the future.

Heme Oxygenase-1 Induction and Anti-inflammatory Actions of Atractylodes macrocephala and Taraxacum herba Extracts Prevented Colitis and Was More Effective than Sulfasalazine in Preventing Relapse

BACKGROUND/AIMS: In inflammatory bowel disease (IBD), repeated bouts of remission and relapse occur in patients and can impose a risk of colitis-associated cancer. We hypothesized that plant extracts of Atractylodes macrocephala (AM) or Taraxacum herba (TH) may be better than sulfasalazine for treating this disease because these extracts can promote additional regeneration. METHODS: Murine intestinal epithelial IEC-6 cells were pretreated with AM or TH before a lipopolysaccharide (LPS)-induced challenge. Acute colitis was induced with 7 days of dextran sulfate sodium (DSS) in male C57BL/6 mice, and extracts of AM and TH were administered for 2 weeks before DSS administration. RESULTS: In vitro studies demonstrated that AM or TH treatment reduced LPS-induced COX-2 and tumor necrosis factor-α mRNA levels but increased heme oxygenase-1 (HO-1). Oral preadministration of AM and TH rescued mice from DSS-induced colitis by inhibiting inflammatory mediators via inactivated extracellular signal regulated kinase and repressed nuclear factor κB and signal transducer and activator of transcription 3, but the effect was weaker for sulfasalazine than that for the extracts. Anti-inflammatory activities occurred via the inhibition of macrophage and T lymphocyte infiltrations. Unlike sulfasalazine, which did not induce HO-1, TH extracts afforded significant HO-1 induction. CONCLUSIONS: Because the AM or TH extracts were far superior in preventing DSS-induced colitis than sulfasalazine, AM or TH extracts can be considered natural agents that can prevent IBD relapse.

Identification of a Copy Number Variation on Chromosome 20q13.12 Associated with Osteoporotic Fractures in the Korean Population

Osteoporotic fractures (OFs) are critical hard outcomes of osteoporosis and are characterized by decreased bone strength induced by low bone density and microarchitectural deterioration in bone tissue. Most OFs cause acute pain, hospitalization, immobilization, and slow recovery in patients and are associated with increased mortality. A variety of genetic studies have suggested associations of genetic variants with the risk of OF. Genome-wide association studies have reported various single-nucleotide polymorphisms and copy number variations (CNVs) in European and Asian populations. To identify CNV regions associated with OF risk, we conducted a genome-wide CNV study in a Korean population. We performed logistic regression analyses in 1,537 Korean subjects (299 OF cases and 1,238 healthy controls) and identified a total of 8 CNV regions significantly associated with OF (p < 0.05). Then, one CNV region located on chromosome 20q13.12 was selected for experimental validation. The selected CNV region was experimentally validated by quantitative polymerase chain reaction. The CNV region of chromosome 20q13.12 is positioned upstream of a family of long non-coding RNAs, LINC01260. Our findings could provide new information on the genetic factors associated with the risk of OF.

Initial Serum Ammonia as a Predictor of Neurologic Complications in Patients with Acute Glufosinate Poisoning

PURPOSE: Glufosinate poisoning can cause neurologic complications that may be difficult to treat due to delayed manifestation. Studies assessing possible predictors of complications are lacking. Although serum ammonia level is a potential predictor of severe neurotoxicity, it has only been assessed via case reports. Therefore, we investigated factors that predict neurologic complications in acute glufosinate-poisoned patients. MATERIALS AND METHODS: We conducted a retrospective review of 45 consecutive glufosinate-poisoning cases that were diagnosed in the emergency department (ED) of Wonju Severance Christian Hospital between May 2007 and July 2014. Patients with a Glasgow Coma Scale (GCS) score of <8, seizure, and/or amnesia were defined to a neurologic complication group. RESULTS: The neurologic complication group (29 patients, 64.4%) comprised patients with GCS<8 (27 patients, 60.0%), seizure (23 patients, 51.1%), and amnesia (5 patients, 11.1%). Non-neurologic complications included respiratory failure (14 patients, 31.1%), intubation and ventilator care (23 patients, 51.1%), shock (2 patients, 4.4%), pneumonia (16 patients, 35.6%), acute kidney injury (10 patients, 22.2%), and death (4 patients, 8.9%). Complications of GCS<8, seizure, respiratory failure, and intubation and ventilator care appeared during latent periods within 11 hrs, 34 hrs, 14 hrs, and 48 hrs, respectively. Initial serum ammonia was a predictor of neurologic complications [odds ratio 1.039, 95% confidence interval (1.001-1.078), p=0.046 and area under the curve 0.742]. CONCLUSION: Neurologic complications developed in 64.4% of patients with acute glufosinate poisoning. The most common complication was GCS<8. Initial serum ammonia level, which can be readily assessed in the ED, was a predictor of neurologic complications.

Elevated Erythrocyte Sedimentation Rate Is Predictive of Interstitial Lung Disease and Mortality in Dermatomyositis: a Korean Retrospective Cohort Study

Interstitial lung disease (ILD) is a major cause of death in patients with dermatomyositis (DM). This study was aimed to examine the utility of the erythrocyte sedimentation rate (ESR) as a predictor of ILD and prognostic marker of mortality in patients with DM. One hundred-and-fourteen patients with DM were examined, including 28 with clinically amyopathic DM (CADM). A diagnosis of ILD was made based on high resolution computed tomography (HRCT) scans. The association between elevated ESR and pulmonary impairment and mortality was then examined. ILD was diagnosed in 53 (46.5%) of 114 DM patients. Cancer was diagnosed in 2 (3.8%) of 53 DM patients with ILD and in 24 (92.3%) of those without ILD (P or = 30 mm/hour had significantly higher mortality than those with ESR < 30 mm/hour (P = 0.002, log-rank test). Patients with a persistently high ESR despite immunosuppressive therapy was associated with higher mortality than those with a normalized ESR (P = 0.039, log-rank test). Elevated ESR is associated with increased mortality in patients with DM due to respiratory failure. Thus, monitoring ESR should be an integral part of the clinical care of DM patients.

A Case of Pneumatosis Cystoides Intestinalis in a Patient with Dermatomyositis

Pneumatosis cystoides intestinalis (PCI), the presence of air within the bowel wall, could be complicated with connective tissue disease. PCI associated with dermatomyositis has rarely been reported. Here, we report on a case of PCI that occurred in a 60-year-old female patient with dermatomyositis, presenting with epigastric discomfort. PCI with pneumoperitoneum was detected on abdominal computed tomography but improved by conservative management without surgery. Treatment for secondary PCI is associated with underlying disease. Also, identification of serious complication, such as bowel perforation, necrosis, and peritonitis, requiring surgical intervention is important.

Appearance of Psoriasis after Tumor Necrosis Factor-alpha Blocker and Use of Ustekinumab or Tocilizumab for Refractory Monoarthritis

Nowadays, tumor necrosis factor-alpha (TNF-alpha) blockers are used for treatment of rheumatoid arthritis, inflammatory bowel diseases, ankylosing spondylitis, psoriatic arthritis, and psoriasis. Paradoxically, there are some reports on the appearance of psoriasis after administration of TNF-alpha blockers. Here, we report on a patient with monoarthritis in a knee joint who experienced psoriasis after TNF-alpha blocker therapy (adalimumab and etanercept). Oral medication was not a treatment option due to patient intolerance; thus, we tried ustekinumab, an anti-interleukin (IL)-12/23 monoclonal antibody used for treatment of psoriasis. Following ustekinumab injection, psoriatic skin lesions and joint symptoms were much improved. However, in the following period, joint pain and swelling became aggravated and synovial fluid cytokine levels including IL-6 and IL-17 were elevated. The treatment was changed to tocilizumab, a humanized monoclonal antibody against IL-6 receptor. After injection, knee joint swelling rapidly subsided without worsening of psoriatic skin lesions.

Response: Genome-Wide Association Study Identifies Two Novel Loci with Sex-Specific Effects for Type 2 Diabetes Mellitus and Glycemic Traits in a Korean Population (Diabetes Metab J 2014;38:375-87)

No abstract available.

Genome-Wide Association Study Identifies Two Novel Loci with Sex-Specific Effects for Type 2 Diabetes Mellitus and Glycemic Traits in a Korean Population

BACKGROUND: Until recently, genome-wide association study (GWAS)-based findings have provided a substantial genetic contribution to type 2 diabetes mellitus (T2DM) or related glycemic traits. However, identification of allelic heterogeneity and population-specific genetic variants under consideration of potential confounding factors will be very valuable for clinical applicability. To identify novel susceptibility loci for T2DM and glycemic traits, we performed a two-stage genetic association study in a Korean population. METHODS: We performed a logistic analysis for T2DM, and the first discovery GWAS was analyzed for 1,042 cases and 2,943 controls recruited from a population-based cohort (KARE, n=8,842). The second stage, de novo replication analysis, was performed in 1,216 cases and 1,352 controls selected from an independent population-based cohort (Health 2, n=8,500). A multiple linear regression analysis for glycemic traits was further performed in a total of 14,232 nondiabetic individuals consisting of 7,696 GWAS and 6,536 replication study participants. A meta-analysis was performed on the combined results using effect size and standard errors estimated for stage 1 and 2, respectively. RESULTS: A combined meta-analysis for T2DM identified two new (rs11065756 and rs2074356) loci reaching genome-wide significance in CCDC63 and C12orf51 on the 12q24 region. In addition, these variants were significantly associated with fasting plasma glucose and homeostasis model assessment of beta-cell function. Interestingly, two independent single nucleotide polymorphisms were associated with sex-specific stratification in this study. CONCLUSION: Our study showed a strong association between T2DM and glycemic traits. We further observed that two novel loci with multiple diverse effects were highly specific to males. Taken together, these findings may provide additional insights into the clinical assessment or subclassification of disease risk in a Korean population.

Comparing the Possible Complications of Endoscopy Dependent on Time in Caustic Poisoned Patients

PURPOSE: Endoscopy has been recommended as a primary procedure for determining the extent of damage and prognosis in patients with caustic ingestions. Endoscopy within the first 24 hours has been suggested, however, such immediate endoscopy is not always possible. Therefore, we wanted to determine complications and possible delayed sequelae after the endoscopy performed dependent on time, including less than 24 hours and more than 24 hours, after ingestion of relatively high toxic caustic agents. METHODS: From January 2005 to May 2013, 105 consecutive patients were diagnosed with caustic poisoning in the emergency department of the Wonju Severance Christian Hospital. Out of 95 patients who underwent endoscopy, while excluding 49 patients who ingested sodium hypochlorite and 15 patients due to insufficient data, 41 patients were ultimately included. We compared general characteristics, complications related to endoscopy, late sequelae, total admission length, and mortality between two groups. RESULTS: Twenty eight patients (68.3%) were diagnosed with acid ingestion. Median endoscopy time was 17.8 (IQR 9.7-36.9) hours and performed in 16 patients (39%) after 24 hours. There were no complications, such as perforation and bleeding in either endoscopy within 24 hours group or endoscopy after 24 hours group. In addition, no difference in ingested materials, endoscopy grade, or late sequelae was observed between endoscopy within 24 hours group and endoscopy after 24 hours group. CONCLUSION: No difference in complications and late sequelae was observed between endoscopy within 24 hours group and endoscopy after 24 hours group when endoscopy was performed based on a clinician's assessment.

Clinical Experience of Symptomatic Spontaneous Isolated Splanchnic Artery Dissection / 대한혈관외과학회지

PURPOSE: Symptomatic spontaneous isolated splanchnic artery dissection (SSISAD) is a rare disease entity. The treatment guideline for SSISAD has not been established. Isolated dissection of splanchnic artery can be clinically asymptomatic or symptomatic. Symptomatic dissection is more important because it can indicate ischemia of abdominal organ. METHODS: A retrospective study was conducted on 15 consecutive patients (mean age, 47.0 years; male, 87%) with SSISAD from January 2006 to July 2013. Each patient had acute onset abdominal pain and was diagnosed with SSISAD by abdominal-pelvic computed tomography. RESULTS: Median follow-up duration was 14.5+/-27.7 months (range, 1 to 79 months). Splanchnic arterial dissection involved celiac artery in three patients and superior mesentery artery in 12 patients. Conservative management (including bowel rest, hypertension medication, anticoagulation, and prophylactic antibiotics) was done in 14 patients. Endovascular treatment with stent insertion was performed in one patient. We experienced favorable clinical outcomes with SSISAD, even though one case needed endovascular treatment. CONCLUSION: Conservative management and selective revascularization could be a treatment option in patients with SSISAD.

Identification of a genetic locus on chromosome 4q34-35 for type 2 diabetes with overweight

The incidence of type 2 diabetes is rising rapidly because of an increase in the incidence of being overweight and obesity. Identification of genetic determinants for complex diseases, such as type 2 diabetes, may provide insight into disease pathogenesis. The aim of the study was to investigate the shared genetic factors that predispose individuals to being overweight and developing type 2 diabetes. We conducted genome-wide linkage analyses for type 2 diabetes in 386 affected individuals (269 sibpairs) from 171 Korean families and association analyses with single-nucleotide polymorphisms of candidate genes within linkage regions to identify genetic variants that predispose individuals to being overweight and developing type 2 diabetes. Through fine-mapping analysis of chromosome 4q34-35, we detected a locus potentially linked (nonparametric linkage 2.81, logarithm of odds 2.27, P=6 x 10-4) to type 2 diabetes in overweight or obese individuals (body mass index, BMI> or =23 kg m-2). Multiple regression analysis with type 2 diabetes-related phenotypes revealed a significant association (false discovery rate (FDR) P=0.006 for rs13144140; FDR P=0.002 for rs6830266) between GPM6A (rs13144140) and BMI and waist-hip ratio, and between NEIL3 (rs6830266) and insulin level from 1314 normal individuals. Our systematic search of genome-wide linkage and association studies, demonstrate that a linkage peak for type 2 diabetes on chromosome 4q34-35 contains two type 2 diabetes-related genes, GPM6A and NEIL3.

Guidewire-Assisted Nasogastric Tube Insertion in Intubated Patients in an Emergency Center / 대한구급학회지

BACKGROUND: The purpose of this study is to identify the usefulness of guidewire-assisted nasogastric tube insertion in intubated patients with cervical spine immobilization or unstable vital signs in an emergency center. METHODS: Thirty-four intubated patients in an emergency center were enrolled in the study. Patients were randomly allocated to the control group or the guidewire group. All patient necks were kept in neutral position during the procedure. In the control group, the nasogastric tube was inserted with the conventional method. A guidewire-supporting nasogastric tube was used in the guidewire group. The success rates of the first attempts and overall were recorded along with complications. RESULTS: The first attempt success rate was 88.2% in the guidewire group compared with 35.2% in the control group (p < 0.001). The overall success rate was 94.2% in the guidewire group and 52.9% in the control group (p = 0.017). Five cases of self-limiting nasal bleeding were reported in the guidewire group, and two cases occurred in the control group. No statistical differences were identified between groups. CONCLUSIONS: Guidewire-assisted nasogastric tube insertion is a simple and useful method in intubated patients with cervical spine immobilization or unstable vital signs.

Genome-Wide Association Study of Liver Enzymes in Korean Children

Liver enzyme elevations, as an indicator of liver function, are widely associated with metabolic diseases. Genome-wide population-based association studies have identified a genetic susceptibility to liver enzyme elevations and their related traits; however, the genetic architecture in childhood remains largely unknown. We performed a genome-wide association study to identify new genetic loci for liver enzyme levels in a Korean childhood cohort (n = 484). We observed three novel loci (rs4949718, rs80311637, and rs596406) that were multiply associated with elevated levels of alanine transaminase and aspartate transaminase. Although there are some limitations, including genetic power, additional replication and functional characterization will support the clarity on the genetic contribution that the ST6GALNAC3, ADAMTS9, and CELF2 genes have in childhood liver function.

The Abnormality of Posterior Default Mode Network in Medication-Naive Attention-Deficit Hyperactivity Disorder Children : Resting State fMRI Study

OBJECTIVES: Characteristic symptoms, including hyperactivity and easy distractibility, in children with attention-deficit hyperactivity disorder (ADHD) suggest that their brain status, even at rest, might differ from that of healthy children. This study was conducted in order to determine whether resting state brain activity is compromised in medication-naive children with ADHD. METHODS: Twenty medication-naive children with ADHD (mean age 10.3+/-2.5) and 28 age- and gender-matched healthy volunteers (mean age 10.3+/-2.0) underwent measurements for resting state brain activity using functional magnetic resonance imaging (fMRI). Among resting state related-independent components (RSICs) extracted from fMRI data using independent component analysis, a significant difference in RSICs was observed between groups, using a mixed Gaussian/gamma model. RESULTS: Except for IQ, which was higher in the healthy control group, no demographic difference was observed between the two groups (p<.001). Significantly less activation of one RSIC, which includes the bilateral precuneus/posterior cingulate cortex, occipito-temporal junction, and anterior cingulate cortex, was observed in the ADHD group, compared with the control group (p<.05). CONCLUSION: An abnormal RSIC, posterior default mode network (DMN), was observed in the medication-naive ADHD group. Results of our study suggest that abnormality of posterior DMN is one of the main pathophysiologies of ADHD.