Time-frequency component analyser and its application to brain oscillatory activity

Currently, event-related potential (ERP) signals are analysed in the time domain (ERP technique) or in the frequency domain (Fourier analysis and variants). In techniques of time-domain and frequency-domain analysis (short-time Fourier transform, wavelet transform) assumptions concerning linearity, stationarity, and templates are made about the brain signals. In the time-frequency component analyser (TFCA), the assumption is that the signal has one or more components with non-overlapping supports in the time-frequency plane. In this study, the TFCA technique was applied to ERPs. TFCA determined and extracted the oscillatory components from the signal and, simultaneously, localized them in the time-frequency plane with high resolution and negligible cross-term contamination. The results obtained by means of TFCA were compared with those obtained by means of other commonly used techniques of ERP analysis, such as bilinear time-frequency distributions and wavelet analysis. It is suggested that TFCA may serve as an appropriate tool for capturing the localized ERP components in the time-frequency domain and for studying the intricate, frequency-based dynamics of the human brain.     

Abdominal confluence of lymph trunks: detectability and morphology on heavily T2-weighted images

OBJECTIVE: Our aims were to evaluate the detectability, configuration, location, and dimensions of the cisterna chyli on heavily T2-weighted images obtained with a single-shot fast spin-echo technique and to determine whether the disorders that have the potential to affect the abdominal lymphatic drainage could change the cisternal dimensions. MATERIALS AND METHODS: Thin-collimated axial and coronal images that were originally obtained for MR cholangiopancreatography in 125 patients were reviewed by three observers individually for the presence of abdominal lymphatic confluence. The configuration, location, and dimensions of hyperintense ductal or saccular structures immediately anterior to the vertebral bodies below the diaphragma were recorded. The differences between the mean values of the diameters of the cisterna chyli obtained in the control group and in groups in which lymphatic drainage was expected to be abnormally high were compared using a one-way analysis of variance test. RESULTS: Abdominal confluence of the lymphatics was shown in 96% of patients. The most common configuration of the cisterna chyli was tubular (42.5%). It was located at the level of L1-2 in 33% of cases and at the midline in 70%. Mean longitudinal, anteroposterior, and transverse diameters of the duct were 33.45 +/- 1.74 (SD) mm, 5.23 +/- 0.13 mm, and 5.23 +/- 0.15 mm, respectively. No significant difference was found in the mean values of antero-posterior, transverse, and longitudinal diameters of the cisterna chyli in the control group and in the groups expected to have an increased flow into the cisterna chyli. CONCLUSION: Abdominal confluence of lymphatics seems to be present on most of the heavily T2-weighted images. Its morphologic details and extensions can be visualized on images reconstructed with a maximum-intensity-projection algorithm. Any disorder does not necessarily lead to dilatation of these lymphatic structures.     

Effect of glutamine supplementation on diarrhea, interleukin-8 and secretory immunoglobulin A in children with acute diarrhea

OBJECTIVE: Glutamine is an important fuel for rapidly dividing cells such as enterocytes and lymphocytes. Exogenous glutamine supplementation in catabolic states preserves intestinal mucosal structure and function, decreases bacterial translocation, and supports normal immunologic responses. This study was planned to assess the effect of glutamine supplementation on duration and severity of diarrhea and to assess its immunomodulatory effect by measuring serum interleukin-8 (IL-8) and salivary immunoglobulin A (sIgA) in children with acute diarrhea. METHODS: In this placebo-controlled, double-blind and randomized trial, 6- to 24-month-old otherwise healthy children admitted to the Diarrheal Diseases Training and Treatment Center with acute diarrhea received either 0.3 g/kg/day of glutamine (n = 63) or placebo (n = 65) for 7 days. Serum IL-8 and sIgA levels were determined on admission and 7 days later. All cases were followed until the diarrheal episode ended. Anthropometric measurements and history of subsequent infectious diseases were monitored monthly for 3 months after treatment. RESULTS: Mean duration of diarrhea in the glutamine treated group was significantly shorter than that of the placebo group (3.40 +/- 1.96 days, 4.57 +/- 2.48 days, respectively; P = 0.004). No differences in serum IL-8 and sIgA were found between groups on admission or 1 week later. During 3 month follow-up, mean weight gain and incidence of infectious diseases were similar in both groups. CONCLUSION: Duration of diarrhea was shorter in children supplemented with glutamine. The beneficial impact of glutamine supplementation seems to be through effects on gastrointestinal mucosa rather than the host immune response.     

Protective effects of melatonin and vitamin E in brain damage due to gamma radiation

Gamma radiation is known to cause serious damage in the brain, and many agents have been used for neuroprotection. In this study, lipid peroxidation levels and histopathological changes in brain tissues of whole-body irradiated rats with likely radiation injury were compared to those with melatonin and vitamin E protection. Forty rats in four equal groups were used. The control group received neither radiation nor medication. The remaining groups received doses of 720 cGy in two equal fractions 12 h apart. The second group received radiation but no medication, the third received radiation plus 100 mg/kg per day of vitamin E i.p., and the fourth received radiation plus 100 mg/kg per day of melatonin i.p. over 5 days. On the 10th postoperative day, all the rats were decapitated and specimens from parietal cortices were analyzed for tissue malondialdehyde (MDA) levels and histopathological changes. Increases in MDA were relatively well prevented by melatonin treatment but less so with vitamin E therapy. On histopathological examination, melatonin significantly reduced the rates of edema, necrosis, and neuronal degeneration, whereas vitamin E reduced only necrosis. Neither substance was capable of preventing vasodilatation. In conclusion, melatonin may be useful in preventing the pathological changes of secondary brain damage as a result of free oxygen radicals generated by irradiation.     

Bronchiolitis obliterans organizing pneumonia presenting with solitary pulmonary nodule and spontan pneumothorax

Chronic obstructive pulmonary disease (COPD) is characterized with progressive airflow limitation as a result of abnormal inflammation due to inhalation of various noxious gases and particulate dusts. COPD is an increasing important health problem that is parallel to the increasing habit of tobacco smoke. Tracheobronchial infections seem to be the most important cause of exacerbation in COPD, however pneumothorax and pulmonary thromboembolism are also important determinant factors in the attack's severity. Since the tobacco smoking is the common risk factor in both COPD and lung cancer, solitary pulmonary nodules especially in smokers should be carefully examined. Bronchiolitis obliterans organizing pneumonia (BOOP) is an uncommon pulmonary disorder, the clinical spectrum of which is variable. In this case report, a COPD patient manifesting spontaneous pneumothorax and solitary pulmonary nodule has been discussed who was diagnosed as BOOP after surgical procedure.     

The comparison of nail and serum trace elements in patients with epilepsy and healthy subjects

The objective of this prospective study was to determine the levels of manganese (Mn), copper (Cu), and zinc (Zn) levels in both nail and serum from patients with epilepsy. For this purpose, levels of these elements were measured in 31 patients with epilepsy and 19 healthy subjects. Element analyses were carried out by atomic absorption spectrophotometer (AAS). Increased Mn levels were detected in nail of patients with epilepsy compared to healthy controls (P<.008). The main nail Zn and Cu levels were found to be unchanged in epileptic patients compared to control subjects. There were no significant differences in serum Mn and Zn levels between epileptic patients and control subjects. However, there was a statistically significant increase in serum Cu levels in patients with epilepsy in comparison with control group (P<.009). Our results demonstrate that some trace element levels may vary in epileptic patients, and because of the more stable status, the analysis of these element levels in some tissues such as nail might be superior to serum analysis.