Sutureless microvascular anastomosis with the aid of heparin loaded poloxamer 407.

BACKGROUND: Anastomosis with tissue adhesives is an alternative method for conventional anastomosis. However, this method has several technical challenges. It requires the use of suture to prevent leakage into lumen and precise application onto all surfaces of the anastomosis site. To solve these problems, poloxamer 407 (P 407) was previously used as a stent. In this study, we made heparinized P 407 (h-P 407) as a new formula. We aimed to successfully use h-P 407 as a stent in sutureless anastomosis in a rat abdominal aorta model. METHODS: Sixty Sprague-Dawley rats were used. In the first group, end-to-end anastomoses were performed with suture; in the second and third groups, sutureless anastomoses were performed with 2-octyl cyanoacrylate. As an intraluminal stent, P 407 was used in the second group, and h-P 407 was used in the third group. Anastomosis time was measured. Lumen width, intimal hyperplasia, and foreign body reaction were assessed histologically. Velocity flow rates and vessel diameters were measured radiologically. Burst strength was measured, and the results were statistically evaluated. RESULTS: Sutureless anastomosis was more rapid than conventional anastomosis. Lumen width was narrower in the suture group. Inflammation and foreign body reaction were more severe in the suture group. There was no radiologic and biomechanical difference between the groups. We found that intimal hyperplasia was less in h-P 407 than in P 407. CONCLUSION: h-P407 can be successfully used as an intraluminal stent for sutureless microvascular anastomosis with tissue adhesives.

Emotion Recognition with Eigen Features of Frequency Band Activities Embedded in Induced Brain Oscillations Mediated by Affective Pictures.

In this study, singular spectrum analysis (SSA) has been used for the first time in order to extract emotional features from well-defined electroencephalography (EEG) frequency band activities (BAs) so-called delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-16 Hz), beta (16-32 Hz), gamma (32-64 Hz). These five BAs were estimated by applying sixth-level multi-resolution wavelet decomposition (MRWD) with Daubechies wavelets (db-8) to single channel nonaveraged emotional EEG oscillations of 6 s for each scalp location over 16 recording sites (Fp1, Fp2, F3, F4, F7, F8, C3, C4, P3, P4, T3, T4, T5, T6, O1, O2). Every trial was mediated by different emotional stimuli which were selected from international affective picture system (IAPS) to induce emotional states such as pleasant (P), neutral (N), and unpleasant (UP). Largest principal components (PCs) of BAs were considered as emotional features and data mining approaches were used for the first time in order to classify both three different (P, N, UP) and two contrasting (P and UP) emotional states for 30 healthy controls. Emotional features extracted from gamma BAs (GBAs) for 16 recording sites provided the high classification accuracies of 87.1% and 100% for classification of three emotional states and two contrasting emotional states, respectively. In conclusion, we found the followings: (1) Eigenspectra of high frequency BAs in EEG are highly sensitive to emotional hemispheric activations, (2) emotional states are mostly mediated by GBA, (3) pleasant pictures induce the higher cortical activation in contrast to unpleasant pictures, (4) contrasting emotions induce opposite cortical activations, (5) cognitive activities are necessary for an emotion to occur.

Effect of different mucosal and acrylic resin surface treatments in a denture retention model for patients with radiotherapy-induced xerostomia.

The purpose of this study was to determine the effect of oral moisturizing agents, denture adhesives, and surface treatments on the retention of an acrylic resin test base dislodged from the maxillary alveolar ridges of xerostomic radiotherapy patients. Acrylic resin test bases prepared for 10 edentulous xerostomia patients were subjected to 8 surface treatment methods: method 1 = untreated dry surface; method 2 = use of Biotène oral moisturizer; method 3 = use of Protefix denture adhesive; method 4 = combination of Biotène and Protefix; method 5 = sandblasting of test bases; method 6 = use of Biotène on sandblasted surface; method 7 = use of Protefix on sandblasted surface; method 8 = combination of Protefix and Biotène on sandblasted surface. After each treatment, a tensile testing apparatus was used to dislodge the inserted test bases, and force values (N) were recorded. A significant difference in retentive force was observed between the 4 Protefix groups and those that did not use denture adhesive (P < .001). There were no differences among the 4 combinations of denture adhesive treatments (P > .05). Sandblasting the denture surfaces did not increase retentive forces alone or in combination with any other treatments. Biotène oral moisturizing agent was used in 4 treatment methods, but only had a significant effect on increasing retentive force when used with a nonsandblasted surface (P < .05). Biotène had no effect on retentive force compared to a nonsandblasted surface without moisturizer or when it was used in combination with any other methods. Protefix denture adhesive offered the greatest improvement in retentive force. Sandblasting the intaglio surface did not improve retentive force. Biotène was reported to improve patient comfort but had minimal effect on retentive force; however, Biotène can be assumed to be a more advantageous method of increasing retention compared to sandblasting (P < .05).

Binocular interactions in the guinea pig's visual-evoked potentials.

In this study, binocular interaction in guinea pigs is evaluated using bioelectrical activities. A difference potential, as evidence of an interaction, is calculated by subtracting the sum of visual-evoked potentials recorded by left and right monocular visual stimulations from the potential recorded by binocular stimulation. A negative monophasic wave with an average amplitude of 15.1 microV and an average latency of 106 ms is observed in the difference potential. This finding implies that the P100 is the main guinea pig visual-evoked potential wave that is affected by binocular interaction. Binocular interaction is also observed in the waves N75 and N140, although with a smaller amplitude. No interaction is observed in the segments of P55 and P200 waves.

Effects of continuous conditioning noise and light on the auditory- and visual-evoked potentials of the guinea pig.

Neurophysiological studies aiming to explore how the brain integrates information from different brain regions are increasing in the literature. The aim of the present study is to explore intramodal (binaural, binocular) and intermodal (audio-visual) interactions in the guinea pig brain through the observation of changes in evoked potentials by generalized continuous background activity. Seven chronically prepared animals were used in the study and the recordings were made as they were awake. Epidural electrodes were implanted to the skulls by using stereotaxic methods. Continuous light for retinal or continuous white noise for cochlear receptors were used as continuous conditioning stimuli for generalized stimulation. To evoke auditory or visual potentials, click or flash were used as transient imperative stimuli. The study data suggest that (a) white noise applied to one ear modifies the response to click in the contralateral ear which is a binaural interaction; (b) continuous light applied to one eye modifies the response to flash applied to the contralateral eye which is interpreted as a binocular interaction; (c) regardless of the application side, white noise similarly modified the response to flash applied to the either eye connoting a nonspecific effect of white noise on vision, independent from spatial hearing mechanisms; (d) on the other hand, continuous light, in either eye, did not affect the response to click applied to any ear, reminding a 'one-way' interaction that continuous aural stimulation affects visual response.

Interaural delay-dependent changes in the binaural interaction component of the guinea pig brainstem responses.

Auditory brainstem responses to monaural and binaural clicks with 23 different interaural time differences (ITDs) were recorded from ten guinea pigs without anesthesia. Binaural interaction component was obtained by subtracting the sum of the appropriately time-shifted left and right monaural responses from the binaural one. With increasing ITD, the most prominent peak of the binaural difference potential so obtained shifted to longer latencies and its amplitude gradually decreased. The way these changes depended on binaural delay was basically similar to that previously observed in a cat study [P. Ungan, S. Yagcioglu, B. Ozmen. Interaural delay-dependent changes in the binaural difference potential in cat auditory brainstem response: implications about the origin of the binaural interaction component. Hear. Res. 106 (1997) 66-82]. The data were successfully simulated by the model suggested in that report. We therefore concluded that the same model, which was based on the difference between the mean onset latencies of the ipsilateral excitation and contralateral inhibition in a typical neuron in the lateral superior olive, their standard deviations, and the duration of the contralateral inhibition, should also be valid for the binaural interaction in the guinea pig brainstem. The results, which were discussed in connection with sound lateralization models, supported a model based on population coding, where the lateral position of a sound source is coded by the ratio of the discharge intensity in the left and right lateral superior olives, rather than the models based on coincidence detection.

CPP and amlodipine alter the decrease in basal acetylcholine and choline release by audiogenic stimulus in hippocampus of ethanol-withdrawn rats in vivo.

Effects of N-methyl-D-aspartate (NMDA) receptor and Ca2+ channel antagonists on extracellular acetylcholine and choline release in the hippocampus of ethanol-withdrawn rats were investigated by in vivo microdialysis. Ethanol was administered to Wistar rats in a liquid diet for 28 days. Basal acetylcholine and choline levels significantly increased at the 24th hour of ethanol withdrawal syndrome (EWS). Either an NMDA receptor antagonist (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) or a calcium channel antagonist amlodipine was administered, and 15 min later, an audiogenic stimulus (100 dB, 1 min) was applied to rats. While audiogenic stimulus increased acetylcholine and had no effect on choline release in control rats, it decreased acetylcholine and increased choline release in ethanol-withdrawn rats. CPP (15 mg/kg) and amlodipine (20 mg/kg) reversed the decrement in acetylcholine and increment in choline release in EW rats. Their effects on acetylcholine and choline release were not different from saline in control rats. Therefore, our findings suggest that, (a) because of adaptive changes in EWS, decrease of the acetylcholine release following audiogenic stimulus may play a role in the triggering of seizures, (b) hippocampal glutamatergic pathway may play a role in the audiogenic stimulus induced decrement of acetylcholine release in EWS, (c) inhibition of this pathway by NMDA receptor and calcium channel antagonists may prevent triggering of the seizures.

Dynamics of the contralateral white noise-induced enhancement in the guinea pig's middle latency response.

The peak-to-peak amplitude of temporal middle latency response (MLR) of the guinea pig, evoked by a click in the contralateral ear, according to the recording side, is increased with the presence of continuous white noise (CWN) in the ipsilateral ear and this specialty is defined as the white noise enhancement (WNE). This phenomenon is evaluated as an interesting electrophysiological finding from the viewpoint of binaural interaction and in this study, its dynamic specifications were investigated. After the beginning of ipsilateral CWN, significant WNE was observed at 275th ms and it reached to a maximum, with an increase more than 40%, at 350th ms. After a habituation occurred, WNE reached to 20% on the 4th second by gradually decreasing and came to a steady state. In the time window between 2 and 5 ms after CWN started, a surprising amplitude decrease is observed. Therefore, CWN causes an effect, like a click, in the short-term and this on-response type effect originates from low level binaural centers, which decreases the MLR amplitude. However, the same CWN increases the MLR amplitude (WNE) by the effects over the high level binaural centers in the succeeding period, by its continuous characteristic.

Dynamics of audio-visual interactions in the guinea pig brain: an electrophysiological study.

Audio-visual interactions and their specifications, evaluated by bioelectrical activities, in guinea pigs are presented in this study. The difference potential, as the evidence of an interaction, was calculated by subtracting the sum of averaged potentials recorded in visual and auditory events from the averaged potential recorded in an event where two stimuli combined in the same sweep. Dynamic investigations have shown an interaction when auditory stimulus is applied 24 ms before and 201 ms after visual stimulation. Latency between the difference potential and auditory stimulus was stable. Directional investigations have shown that the interaction is not observed when auditory and/or visual stimulation is used ipsilaterally, according to the recording side.