Ant Colony Optimization Based Feature Selection Method for QEEG Data Classification

Objective

Many applications such as biomedical signals require selecting a subset of the input features in order to represent the whole set of features. A feature selection algorithm has recently been proposed as a new approach for feature subset selection.

Methods

Feature selection process using ant colony optimization (ACO) for 6 channel pre-treatment electroencephalogram (EEG) data from theta and delta frequency bands is combined with back propagation neural network (BPNN) classification method for 147 major depressive disorder (MDD) subjects.

Results

BPNN classified R subjects with 91.83% overall accuracy and 95.55% subjects detection sensitivity. Area under ROC curve (AUC) value after feature selection increased from 0.8531 to 0.911. The features selected by the optimization algorithm were Fp1, Fp2, F7, F8, F3 for theta frequency band and eliminated 7 features from 12 to 5 feature subset.

Conclusion

ACO feature selection algorithm improves the classification accuracy of BPNN. Using other feature selection algorithms or classifiers to compare the performance for each approach is important to underline the validity and versatility of the designed combination.     

Imaging of neuroendocrine tumors: accuracy of helical CT versus SRS

Background: We retrospectively compared the accuracy of somatostatin receptor scintigraphy (SRS) with that of helical computed tomography (CT) in the detection and localization of primary and metastatic neuroendocrine tumors.Methods: A medical record search identified 27 patients with known or clinically suspected neuroendocrine tumors who underwent helical CT and SRS within 3 months of one another at our institution. CT images were evaluated retrospectively by two blinded radiologists who used consensus reading. Images were evaluated for the presence or absence of primary tumor and hepatic and extrahepatic metastases. CT results were compared with the SRS report as interpreted by the nuclear medicine physicians. The results of the surgical, clinical follow-up, and pathologic findings were considered as the gold standard. Sensitivity, specificity, and accuracy were calculated for both imaging techniques. In addition, McNemar analysis was performed to determine statistically significant differences between CT and SRS.Results: Helical CT was more sensitive than SRS in the detection of extrahepatic metastases, and the difference between the two imaging modalities was statistically significant (p = 0.0312) as determined by the McNemar chi-square test. However, the difference between CT and SRS in detecting primary neuroendocrine tumors, hepatic metastasis, and combined hepatic and extrahepatic metastasis was not statistically significant (p = 0.625, 1.000, and 1.000, respectively).Conclusion: Helical CT and SRS have similar sensitivity, specificity, and accuracy in detecting primary neuroendocrine tumor and hepatic metastasis. However, helical CT appears to be more sensitive in detecting extrahepatic metastasis from primary neuroendocrine tumors.     

Gluteal region morphology: the effect of the weight gain and aging

The gluteal region is an important secondary sexual character itself and it has its place in the concept of the beauty in all communities. Interestingly, as far as we know, there is not any previous study addressing gluteal region morphology in an objective way in the aesthetic surgery literature. The aim of this study was to define the changes of the gluteal region morphology with aging and weight gain. Beside body weight, a total of five distances between predetermined anatomic points in gluteal region were measured on randomly selected 115 female volunteers, with their age ranging from 17 to 48 years (mean 22.7). All the records were analyzed by a correlation matrix using computer-based SPSS 7.5 program. As women grow older, the width of the gluteal region decreases and the gluteal sulcus elongates laterally and inferiorly. Contrary to aging, with weight gain the gluteal region becomes wider as the gluteal sulcus gets shorter. Although the subject does not sound new, our study is the first, documenting the changes in morphology of the gluteal region in relation to weight gain and aging in an objective way.     

Elevated plasma nociceptin level in patients with Wilson disease

Plasma level of nociceptin, the endogenous agonist of orphanin FQ/ORL1 receptor was found to be significantly elevated in Wilson disease patients (13.98+/-2.44pg/ml, p<0.001, n=20) compared to age-matched healthy controls (9.18+/-1.63pg/ml, n=25). Wilson disease is an autosomal recessive disorder of copper metabolism caused by mutation of the gene ATP7B leading to toxic copper accumulation in the liver and other organs such as brain, kidney and cornea. Measurements were performed by 125I-radioimmunoassay. Neither sex differences nor correlation between plasma nociceptin levels and liver function test results were found. It is suggested that elevated plasma nociceptin level found in Wilson disease patients is due to inhibition of nociceptin-inactivating Zn-metallopeptidases (aminopeptidase N (APN) and endopeptidase 24.15) by the toxic copper deposits in liver and/or brain.     

Childhood idiopathic nephrotic syndrome in Turkey

BACKGROUND: It has been reported that there are racial and regional differences in peak incidence age, histopathological features and response to steroid therapy in childhood idiopathic nephrotic syndrome. METHODS: One hundred and thirty-eight patients with a diagnosis of idiopathic nephrotic syndrome, followed up in 1994-2000, were assessed retrospectively. The aim of this study was to assess the patients' response pattern to steroid therapy, to determine whether the duration of the initial steroid therapy alters the steroid response pattern of the disease and to assess renal biopsy results. RESULTS: One hundred and fourteen patients who initially received only steroid therapy and were followed up regularly were classified according to response pattern. Of the 114 patients, 30 children had an initial response, 25 children had infrequent relapse, 19 had frequent relapse, 25 had steroid dependence and 15 children had steroid resistance. The 99 patients with steroid responsive nephrotic syndrome were divided into two groups with respect to duration of the initial steroid therapy. There was no statistically significant difference between standard and short therapy groups with respect to the steroid response patterns. Percutaneous renal biopsy was performed in 43 of the 138 patients. Mesengioproliferative glomerulonephritis was the most common histopathological lesion, followed by membranoproliferative glomerulonephritis. The proportions of membranous glomerulonephritis, focal segmental glomerulosclerosis and minimal change nephrotic syndrome were low in our group. CONCLUSIONS: Our study group is similar to one reported from Saudi Arabia with respect to the steroid response pattern and to Saudi Arabian and Nigerian reports with respect to the histopathology. Although it has been reported that short initial steroid therapy was followed by a higher rate of relapses, there was no statistically significant difference between standard and short therapy groups with respect to the relapse rate in our study group.     

Using two ipsilateral double j ureteral stents for extrinsic ureteral obstruction due to colon carcinoma

Although double J (DJ) ureteral stents are widely used in extrinsic ureteral obstruction, there are few studies using ipsilateral two DJ stents in the same ureter. We report using ipsilateral two ureteral DJ stents in the same ureter in a patient with extrinsic ureteral obstruction due to colon carcinoma.     

Penile prosthesis extrusion due to gonococcal infection

Gonococcal infection of a penile prosthesis is a rare presentation of a common disease. Here we report two cases of penile prosthesis extrusion due to gonococcal infection.     

Circulating nociceptin levels during the cluster headache period

The trigeminal innervation of the dura and its vessels has a prominent role in the mechanism of cluster headache. Nociceptin, an opioid neuropeptide, is the endogenous ligand of the OP-4 receptor, with both algesic and analgesic properties depending on the site of action. Nociceptin and its receptor are expressed by trigeminal ganglion cells where they co-localize with calcitonin gene-related peptide, a marker peptide of the trigeminovascular neurones. Nociceptin inhibits neurogenic dural vasodilatation, a phenomenon related to trigeminovascular activation. To explore its possible involvement in cluster headache, we studied circulating levels of nociceptin when attack-free during the cluster period, and also after the termination of the cluster period, using radioimmunoassay. In 14 cluster headache patients nociceptin levels during the cluster period were significantly lower than in age-, and sex-matched controls (4.91 +/- 1.96 vs. 9.58 +/- 2.57 pg/ml, P < 0.01). After the termination of the cluster period nociceptin levels (8.60 +/- 1.47 pg/ml) were not statistically different from controls. Nociceptin levels did not correlate with age, length of disease or episode length. Lower nociceptin levels during the cluster period may result in a defective regulation of trigeminal activity that might not protect sufficiently against the attacks.     

Reduced bone mineral density in childhood chronic idiopathic thrombocytopenic purpura treated with high-dose methylprednisolone

PURPOSE: To evaluate whether repeated courses of high-dose methylprednisolone (HDMP) affect the lumbar spine bone mineral density (BMD) in children with chronic idiopathic thrombocytopenic purpura (ITP). MATERIALS AND METHODS: This study included 24 patients with chronic ITP and 149 healthy controls. The patients were allocated into three groups according to the number of HDMP courses (30 mg/kg per day as a single dose for 7 days); group 1 (10 patients), group 2 (9 patients), and group 3 (5 patients) had received less than 5, 6-10, and more than 10 courses, respectively. Lumbar spine BMD and body composition were measured using dual energy X-ray absorptiometry of lumbar spine (L2-L4), and volumetric bone mineral density (vBMD) values were calculated and compared with the controls. The z score of the vBMD was also calculated and compared in the patients of each other groups. Serum markers of the bone turnover were measured to exclude other factors that could effect BMD. RESULTS: The vBMD values of the patients, corrected BMDs for age, were significantly lower than the values of controls (P = 0.018). It was significantly lower in group 3 than groups 1 and 2 (P = 0.005 and P = 0.006, respectively), but there was no statistically significant difference between groups 1 and 2 (P = 0.87). The vBMD z scores were significantly lower in group 3 than in groups 1 and 2 (P = 0.003 and P = 0.004, respectively), and also in group 2 than in group 1 (P = 0.034). There were a weak negative correlation between the cumulative dose of HDMP and vBMD (r = -0.39, P = 0.054), and strong negative correlation between the cumulative dose of HDMP and vBMD z score (r = -0.63, P = 0.001). CONCLUSION: Children with chronic ITP are at risk for decreased BMD because of the repeated courses of HDMP; especially more than 2100 mg of cumulative dose. We therefore recommend that BMD should be monitored in patients with chronic ITP who received repeated courses of HDMP.     

Carcinosarcoma of the urinary bladder: dynamic contrast-enhanced MR imaging with clinical and pathologic correlation

OBJECTIVE: This article describes the MR imaging features of carcinosarcoma of the urinary bladder with clinical presentation and pathologic correlation in three adults. CONCLUSION: Carcinosarcoma of the urinary bladder is a rare and aggressive tumor that has a clinical presentation similar to that of transitional cell carcinoma of the bladder. Dynamic gadolinium-enhanced MR imaging features are discussed.