1,815 research outputs found
Auditory steady-state responses to click trains from the rat temporal cortex
No full textIn order to investigate the mechanisms underlying the generation of steady-state responses (SSRs), auditory evoked potentials elicited by click trains presented at several stimulation rates (30, 40, 50, 60 Hz) were recorded in 7 awake rats by means of epidural electrodes placed over the temporal cortex. Mean amplitude-rate function calculated on the recorded responses appeared almost flat and showed the maximum value at 50 Hz, while mean phases showed a linear increase when increasing the stimulation rate. In each rat, predictions of the recorded responses at 30, 40, 50 and 60 Hz were synthesized by superimposing middle-latency auditory evoked potentials (MAEPs) at suitable time intervals at each rate. Mean amplitudes calculated on the predicted curves decreased linearly when increasing the stimulation rate and appeared higher in comparison to those obtained from the recorded SSRs. Predicted phases showed a linear increase when increasing the stimulation rate and were leading with respect to corresponding phase values calculated for recorded SSRs. Our findings indicate that the MAEP superimposition mechanism does not adequately predict the generation of temporal recorded SSRs in rats. This was explained by admitting that phenomena related to the recovery cycle and, to a lesser extent, to rate-dependent facilitating effects come into play
Pancreatic enzyme supplementation after gastrectomy for gastric cancer: a randomized controlled trial
No full textBackground: Gastrectomy for gastric cancer is a significant cause of secondary exocrine pancreatic insufficiency. Pancreatic enzyme replacement therapy may influence nutritional status and quality of life after gastrectomy, but the pertinent clinical research to date remains controversial. A randomized controlled trial to test this hypothesis was carried out. Methods: After gastrectomy, 43 patients with gastric cancer were randomly assigned to a normal diet (Normal-d; n = 21) or to a pancreatic enzyme supplementation diet (PES-d; n = 22) and were followed up during a 12-month period, assessing nutritional status and quality of life through body mass index (BMI), instant nutritional assessment (INA) class status, serum pre-albumin (SPA) values, and GastroiIntestinal Quality of Life Index (GIQLI). Results: BMI was not significantly influenced by the type of diet; INA class status was significantly improved in the PES-d arm, particularly during the first 3 months after gastrectomy; SPA levels increased in both arms at 6 months after gastrectomy, reaching significantly higher values in the PES-d arm at 12 months. GIQLI was not significantly influenced by the type of diet throughout the follow-up period; however, this index significantly improved in the PES-d arm between the first and third month after gastrectomy. Conclusions: PES-d improves nutritional status and quality of life after gastrectomy for gastric cancer, particularly within 3 months from the operation. A larger, multicenter trial is necessary to address the potential influence of several confounding variables such as disease stage and adjuvant treatments
Adaptation and resonance phenomena in the generation of the auditory steady-state responses (SSRs) in rats
No full textFAD Cristal. Il paziente con ipeuricemia cronica con e senza deposito di urato. Dal danno nefro-articolare al rischiocardiometabolico.
No full textDescrizione delle principali evidenze della letteratura scientifica relative alla associazione tra iperuricemia cronica con e senza depositi di urato e malattie cardiovascolari e renali e della possibilità che il trattamento ipouricemizzante possa esercitare effetti benefici in termini di protezione cardio-nefro-metabolica
Possible modulation of auditory middle latency responses (MLRs) by nitric oxide (NO) in the inferior colliculus of anaesthetized rats.
No full textNitric oxide (NO) is a short-lived radical species endowed with intercellular signalling functions in the mammalian brain. In the present study we have investigated the effects of focal injection into one inferior colliculus of N-omega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, on the acoustic middle latency responses (MLRs) evoked by click stimuli and recorded from the auditory cortex in anaesthetized rats. Microinfusion of L-NAME (1.0 mM) did not alter the latency of MLRs nor did it affect the evoked brain stem responses (ABRs), By contrast, L-NAME reduced P-1a-N-1 amplitude of MLRs by 51.7 +/- 6.6% (mean +/- SEM; n = 5) and almost complete recovery to background amplitude was obtained 15-25 min after treatment. The less active isomer, D-NAME (1.0 mM; n = 5), failed to produce consistent effects on the evoked MLRs. A higher concentration of L-NAME (5.0 mM; n = 5) yielded a 69.0 +/- 13.3% inhibition whereas maximum inhibition produced by 0.5 mM (n = 3) L-NAME was congruent to 10% of control value. The inhibitory effect typically evoked by 1.0 mM L-NAME was prevented by treating rats with L-arginine (5.0 mM; n = 5), the endogenous precursor of NO synthesis. Reduction of MLR amplitude was also obtained in rats receiving intracollicular injection of dizocilpine (MK801; 1.0 mu M) and LY274614 (1.0 mM), two selective N-methyl-D-aspartate (NMDA) receptor antagonists. In conclusion, the present data support a role for intracollicular NO in the processing and transmission of the acoustic input to the auditory cortex in the rat
A Versatile and Efficient 0.1-to-11 Gb/s CML Transmitter in 40-nm CMOS
No full textWe present a wireline transmitter (TX) for re-configurable chip-to-chip links. The proposed design features a frequency-adaptive clock chain, a fast 16:1 clocked-CMOS multiplexer (C2MOS MUX) tree, and a full-rate synchronous current-mode logic (CML) clock driver. A prototype realized in 40-nm CMOS accomplishes a wide 0.1-to-11 Gb/s operation range (fmax/fmin = 110×). At 11 Gb/s, the prototype achieves 3.98 pJ/bit for a bit error rate (BER) < 10-12 with a 60.9-ps eye width.Accepted author manuscriptElectronic
Is nitric oxide (NO) involved in the transmission of acoustic input to the rat auditory cortex?
No full textNO has been proposed to act as an intercellular messenger, possibly involved in neuronal plasticity and in the transmission of somatosensory information. Aim of the present study is to check whether, at the infedor colliculus (IC) level, NO may participate in the processing and transmission of acoustic signals to the auditory cortex of the rat. Animals were anaesthetised with ketamine and xylazine (66 and 13 mg/kg, respectively, i.p.) and implanted with a stainless steel guide cannula to allow drug injection into the IC (0.5-1.0 rtl at 1.0 lal/min rate). Auditory middle latency (MLR) and brain stem (ABR) responses were evoked by click stimuli of supramaximaI intensity at 4/s and recorded from the auditory cortex by Ag/AgCt electrodes. IC injection of N%nitro- L-arginine methyl ester (L-NAME, 1.0 mM), an inhibitor of NO synthase (NOS), reduced by 51.7--~.6% (n=5) the amplitude of Pla-N1 com- ponent of MLRs without significantly affecting the latency of MLRs as well as ABRs. This inhibitory effect was concentration-dependent and it ranged from 5.5_+3.2% for the concentration of 0.5 mM (n=3) to 69.0_+ 3.3% for 5.0 mM (n=5). L-NAME injection performed 10 min after pre- treatment with the endogenous precursor of NO, L-arginine (5.0 raM), produced 24.2_+3.6% reduction of P1,-N~ amplitude and this was significantly lower (P<0.01) than that elicited by L-NAME given alone. IC injection of D-NAME (1.0 mM; n=5), the less active isomer of NAME, yielded no significant decrease in Pla-N1 amplitude. IC infusion of dizo- cilpine (MK801; 1.0 pM, n=5) or LY274614 (1.0 mM; n=3), two selective NMDA receptor antagonists, reduced P~,-N~ amplitude by 48.2_+7.4% and 83.7_+5.0%, respectively. The stereospecific and concentration- dependent effects of L-NAME suggest that IC NO is involved in the transmission of acoustic input to the auditory cortex. Stimulation of NOS activity under our experimental conditions might be due to a rise in intracellular Ca2÷levels induced by NMDA-receptor activation
Possible role of intracollicular synthesis of nitric oxide (NO) in the transmission of acoustic signals to the rat auditory cortex
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