Spectral changes in electrical activity of pylorus due to L-NAME induced hypertrophic pyloric stenosis.

OBJECTIVES: To investigate the relation between hypertrophic pyloric stenosis (HPS) and the changes in the myoelectrical activity of the pyloric and gastric areas. METHODS: Three pregnant females, at 14 days of gestation two of which were named as D14n (NOS inhibitor group) and one was named as D14c (control). From the beginning of the study until the end of gestation, rats in D14n group received nitric oxide synthase inhibitor L-NAME for administrating their pups, and the rat in D14c group was drinking water for 21 days. The pups of each group underwent laparotomy at 42 days of their life and myoelectrical signals of their pyloric and gastric regions were recorded via bipolar electrodes and then evaluated through signal processing. RESULTS: Signal analysis showed that HPS induced pyloric segment reveals a suppressed spectral component that was detected in normal pyloric segment. The HPS induced pyloric segment also revealed higher power/ min and +/- SD compared to that of normal and gastric areas. In the pyloric segment, while the number of interstitial cells of Cajal (ICC) was lesser, the number of smooth muscle cells was higher than in the pyloric segment of controls. CONCLUSIONS: The spectral differentials depend on the type, population and condition of locally specialized muscular mechanism which can be affected from HPS. The HPS also has a relation to specific cells, such as ICC that generates NO, provoke the spontaneous pacemakers and biological slow waves (Tab. 1, Fig. 1, Ref. 19).

Combating endometriosis by blocking proteasome and nuclear factor-kappaB pathways.

BACKGROUND: The objective of this study is to investigate the effect of pyrrolidine dithiocarbamate [PDTC; a nuclear factor-kappaB (NF-kappaB) inhibitor] and bortezomib (Velcade; a proteasome inhibitor) on the development of experimental endometriotic implants in rats. METHODS: Endometriosis was surgically induced in 30 rats using the method of Vernon and Wilson. Three weeks later the viability and volume of the implants were recorded and classified. Afterwards, rats were put into three groups with equal numbers. The groups were labelled as the control, the PDTC and the bortezomib groups. Seven days after treatment, a third laparotomy was done and the volume of implants was measured again. The animals were then sacrificed, and the implants were stained with Ki67, proliferating cell nuclear antigen (PCNA), CD34, CD31 and Masson's trichrome histochemical staining. RESULTS: In 80% of the implanted rats, vesicles at the suture region were observed, and the rats graded according to average vesicle diameter (D) as: Grade 1 (no vesicle, 20% of rats), Grade 2 (D < 2 mm, 33.3% of rats), Grade 3 (2 mm 4.5 mm, 26.7% of rats) and Grade 4 (D > 4.5 mm, 20% of rats). After treatment with PDTC or bortezomib, these percentages were decreased for Grades 3 and 4, and increased in Grade 1. The post-treatment implant volumes were decreased in the PDTC and bortezomib groups (P < 0.002 and P < 0.001), and slightly increased in the control group (P = 0.279). In the PDTC and bortezomib groups, CD34, CD31, PCNA and Ki67 expression levels were similar but were significantly reduced compared with the control group. CONCLUSIONS: PDTC and bortezomib may represent a novel therapeutic strategy for treatment of endometriosis.

Analysis of the time-varying energy of brain responses to an oddball paradigm using short-term smoothed Wigner-Ville distribution.

Cognitive brain responses to external stimuli, as measured by event related potentials (ERPs), have been analyzed from a variety of perspectives to investigate brain dynamics. Here, the brain responses of healthy subjects to auditory oddball paradigms, standard and deviant stimuli, recorded on an Fz electrode site were studied using a short-term version of the smoothed Wigner-Ville distribution (STSW) method. A smoothing kernel was designed to preserve the auto energy of the signal with maximum time and frequency resolutions. Analysis was conducted mainly on the time-frequency distributions (TFDs) of sweeps recorded during successive trials including the TFD of averaged single sweeps as the evoked time-frequency (ETF) brain response and the average of TFDs of single sweeps as the time-frequency (TF) brain response. Also the power entropy and the phase angles of the signal at frequency f and time t locked to the stimulus onset were studied across single trials as the TF power-locked and the TF phase-locked brain responses, respectively. TFDs represented in this way demonstrated the ERP spectro-temporal characteristics from multiple perspectives. The time-varying energy of the individual components manifested interesting TF structures in the form of amplitude modulated (AM) and frequency modulated (FM) energy bursts. The TF power-locked and phase-locked brain responses provoked ERP energies in a manner modulated by cognitive functions, an observation requiring further investigation. These results may lead to a better understanding of integrative brain dynamics.

Time-frequency analysis of ECG signals using an image processing technique.

To overcome limitations that occur in time-frequency representations (TFR) of signals, a new technique that considers the ambiguity function (AF) is proposed. This work firstly introduces a filtering technique that is based on the processing of the image of the AF of the signal. Secondly it shows the potential of this technique in application to ECG signal analysis by comparing some kernel-based techniques. The analytic form of the ECG is used to eliminate aliasing and the cross terms generated by the negative spectra that appear in TFRs. This work shows that data adaptive time-frequency analysis of the ECG by image processing techniques is possible and potentially useful.