Disruption of effective connectivity from the dorsolateral prefrontal cortex to the orbitofrontal cortex by negative emotional distraction in obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) has been associated with abnormal cognitive and emotional functions and these dysfunctions may be dependent on the disruption of dynamic interactions within neuronal circuits associated with emotion regulation. Although several studies have shown the aberrant cognitive-affective processing in OCD patients, little is known about how to characterize effective connectivity of the disrupted neural interactions. In the present study, we applied effective connectivity analysis using dynamic causal modeling to explore the disturbed neural interactions in OCD patients.

METHOD

A total of 20 patients and 21 matched healthy controls performed a delayed-response working memory task under emotional or non-emotional distraction while undergoing functional magnetic resonance imaging.

RESULTS

During the delay interval under negative emotional distraction, both groups showed similar patterns of activations in the amygdala. However, under negative emotional distraction, the dorsolateral prefrontal cortex (DLPFC) and the orbitofrontal cortex (OFC) exhibited significant differences between groups. Bayesian model averaging indicated that the connection from the DLPFC to the OFC was negatively modulated by negative emotional distraction in patients, when compared with healthy controls (p < 0.05, Bonferroni-corrected).

CONCLUSIONS

Exaggerated recruitment of the DLPFC may induce the reduction of top-down prefrontal control input over the OFC, leading to abnormal cortico-cortical interaction. This disrupted cortico-cortical interaction under negative emotional distraction may be responsible for dysfunctions of cognitive and emotional processing in OCD patients and may be a component of the pathophysiology associated with OCD.

Pantothenate kinase-associated neurodegeneration in Korea: recurrent R440P mutation in PANK2 and outcome of deep brain stimulation

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate the mutation status of PANK2 among Korean patients with pantothenate kinase-associated neurodegeneration (PKAN) and to document the outcome of pallidal deep brain stimulation (DBS).

METHODS

Direct sequencing and deletion/duplication analysis of PANK2 were conducted in 12 patients (11 unrelated) with PKAN, diagnosed on the basis of extrapyramidal dysfunction and the 'eye-of-the-tiger sign' on brain magnetic resonance imaging (MRI). Pallidal DBS was conducted in four patients, and the outcomes were measured using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS).

RESULTS

A PANK2 mutation was identified in both alleles in all patients. The most prevalent mutation was c.1319G>C (p.R440P) in 8/22 mutated alleles (36%). An intragenic deletion ranging from exons 2 to 4 was found in one allele (1/22, 4.5%) using deletion/duplication analysis. The outcome of pallidal DBS was favorable in two patients with atypical PKAN and moderate severity of dystonia. However, two patients with typical PKAN and relatively severe symptoms showed variable responses.

CONCLUSIONS

The c.1319G>C (p.R440P) mutation appears to be a founder genotype among Korean patients with PKAN. Furthermore, this study provides additional data for the recent international effort to evaluate the efficacy of pallidal DBS in the treatment of patients with PKAN.

Transforming growth factor beta receptor II (TGFBR2) polymorphisms and the association with nonsegmental vitiligo in the Korean population

The precise cause of vitiligo is unknown. However, autoimmunity is considered the most likely aetiology, especially in nonsegmental vitiligo (NSV). In this study we determined whether or not the transforming growth factor beta receptor II (TGFBR2) gene contributes to susceptibility for NSV in the Korean population. Blood samples were collected from 415 controls and 233 cases. We selected three single nucleotide polymorphisms (SNPs) in the TGFBR2 gene. The genotypes of the SNPs were determined using direct sequencing. All of the SNPs were significantly different between the vitiligo patients and controls (rs2005061, co-dominant, dominant, recessive, P < 0.05; rs3773645, co-dominant, dominant, recessive, P < 0.05; rs3773649, co-dominant, recessive, P < 0.05). In addition, haplotype 1 (CG) and haplotype 2 (GA) of the linkage disequilibrium (LD) block were also associated with a risk of NSV. The present study suggests that TGFBR2 might be related to NSV.

Determination of low (137)Cs concentration in seawater using ammonium 12-molybdophosphate adsorption and chemical separation method

A new method has been developed for analyzing (137)Cs in a small volume of seawater. Ammonium 12-molybdophosphate (AMP) was used two times during pretreatment procedure. The first step was to adsorb (137)Cs in seawater samples into AMP in order to reduce sample volume, and the second was to remove (87)Rb, interference nuclide for beta counting. The AMP adsorbing (137)Cs was dissolved by sodium hydroxide solution, and then (137)Cs was finally formed to be cesium chloroplatinate precipitate by adding 10% hexachloroplatinic acid. The beta rays emitted from (137)Cs were measured with a low background gas-proportional alpha/beta counter. This method was applied to several seawater samples taken in the East Sea of Korea. Compared to the routinely used gamma-spectrometry method, this new AMP method was reliable and suitable for analyzing (137)Cs in deep seawater.

Immortalization of human embryonic fibroblasts by overexpression of c-myc and simian virus 40 large T antigen

SV40 large T antigen, a viral oncoprotein, is known to immortalize human diploid fibroblast by soaking up cellular RB and p53, but its frequency is extremely low. Additional genetic alteration is necessary for single-step immortalization. We attempted to find out what this alteration is by overexpressing cellular signal mediator genes; c-myc and cyclin D frequently amplified in many cancer cells. Overexpression of cyclin D did not affect the immortalization, but, overexpression of c-myc along with T antigen could immortalize normal human diploid fibroblast. Several cellular markers tested during immortalization process showed that p21, a cyclin-dependent kinase inhibitor and a marker of cellular senescence, disappeared in the life span-extended cells by T antigen and in the immortalized cells by c-myc. p21 was, however, elevated in the senescent cells and in the cells of crisis. Interestingly, p16 was upregulated whenever T antigen is overexpressed. Telomerase activity was also activated only in the immortalized cells. These results suggest that overexpression of c-myc contributes to immortalization of human diploid fibroblast by activating telomerase activity and suppressing p21 activity.

Novel anti-calcification treatment of biological tissues by grafting of sulphonated poly(ethylene oxide)

Biological porcine tissue was modified by the direct coupling of sulphonated poly(ethylene oxide) (PEO-SO3) containing amino acid end groups after glutaraldehyde fixation. The calcification of the modified tissue [bioprosthetic tissue (BT)-PEO-SO3] and control (BT control) was investigated by in vivo rate subdermal, canine aorta-illiac shunt and right ventricle-pulmonary artery shunt implantation models. Less calcium deposition of BT-PEO-SP3 than of BT control was observed in in vivo tests. Such a reduced calcification of BT-PEO-SO3 can be explained by decreases of residual glutaraldehyde groups, a space filling effect and, therefore, improved biostability and synergistic blood-compatible effects of PEO and SO3 groups after the covalent binding of PEO-SO3 to tissue. This simple method can be a useful anti-calcification treatment for implantable tissue valves.

Chemical modification of implantable biologic tissue for anti-calcification

Biologic porcine tissue was modified by coupling sulfonated polyethyl-eneoxide (PEO-SO3) and the effect of modification on calcification was evaluated in vitro and in vivo. The modification process involves grafting PEO-SO3 to porcine valve leaflet either by carbodiimide (EDC) activation or by direct coupling using glutaraldehyde. Thermal property, measured by differential scanning calorimetry, showed that the shrinkage temperature of modified tissue increased compared with control tissue and fresh tissue, suggesting increased thermal stability. Resistance to collagenase digestion revealed that modified tissues have greater resistance to enzyme digestion than do control tissues. In vitro calcification showed that modified tissues have less calcium deposition than do control tissues. In vivo calcification, using a rat subcutaneous implantation model, also showed less calcification of modified tissue than that of control. The resistance of modified tissue to collagenase, higher shrinkage temperature, and reduced calcification, when compared with control tissue, attest to the usefulness of this chemical modification for implantable biologic tissue.