Autonomic nervous system dysregulation in irritable bowel syndrome.

BACKGROUND: Autonomic nervous system (ANS) regulation may be altered in functional diseases, including irritable bowel syndrome (IBS), but published data are not clear to date. The aim of the study was to analyze ANS function in IBS subjects classified by Rome III criteria and healthy controls using standardized technique. METHODS: ANS activity was evaluated by autoregressive spectral analysis of RR interval and systolic arterial pressure variabilities, to obtain indices of sympatho-vagal modulation of the heart and of spontaneous cardiac baroreflex (α index). A symptom list was used to score 18 somatic complaints (score 0-180) (4SQ). Fatigue and stress were assessed through the use of a global scoring index (0-10). KEY RESULTS: We enrolled 41 IBS subjects (29 F, age 40 ± 2 years) and 42 healthy matched controls. Heart rate was higher in IBS than control subjects (69 ± 2 vs 61 ± 1; p < 0.001). The total variance of RR interval variability, and α index, were significantly lower in IBS compared to controls (1983.12 ± 384.64 ms(2) vs 4184.55 ± 649.59 ms(2) ; 18.1 ± 2 ms/mmHg vs 29 ± 3 ms/mmHg; p < 0.01). The α index results showed an inverse correlation with stress scores and somatic symptoms. CONCLUSIONS & INFERENCES: IBS subjects display a significant reduction in α index, an established marker of cardiac baroreflex. ANS dysfunction appears to be involved in the pathophysiology of IBS and its assessment may open new perspectives for clinical management of patients suffering from IBS.

[Comparison of limited weight values and the sensitivity of analytical methods used for the detection of toxic atmospheric agents in working places]. / Confronto fra i valori limite ponderati e le sensibilità dei metodi di analisi degli agenti tossici nell'atmosfera degli ambienti di lavoro.

This research has been carried out in order to estimate minimum sampling periods for the substances detailed in the VLP table given by the Italian Occupational Medicine Service and the Industrial Hygiene Group. These data take the following points into consideration: 1) sensitivity of the analytical method; 2) value and condition of sample at fulfilment of sampling periods; 3) sampling speed; 4) VLP, with special reference to ceiling value for very short exposure. As to dust the minimum period required is about 1 minute for numeric sampling, and 35 minutes for gravimetric sampling. 85% from the above-mentioned substances can be sampled at minimum periods which range from 1 to 5 minutes.