Cardiovascular effects of gastric intubation and distension in healthy humans

Few data exist on the effect of upper gut stimuli on the cardiovascular system. Aim of our study was to evaluate the cardiovascular effects of gastric intubation and distension. Eleven healthy subjects (eight men, aged 21-30 years) were studied and a non-invasive beat-to-beat cardiovascular monitoring system was used. After 15-min basal recording, a bag catheter was positioned in the proximal stomach and connected to a barostat. Recordings were first performed for 15 min with the bag deflated, then during inflation of air using a 100 mL per 2 min stepwise protocol until epigastric discomfort was reported, and finally for 15 min with the bag inflated at 75% of discomfort volume separed from the preceding period by 10 min with the bag deflated. Presence of the deflated bag catheter significantly increased mean arterial pressure. Stepwise distension progressively increased heart rate and cardiac index, while mean arterial pressure was affected only at discomfort volume. Peripheral resistances and systemic plasma catecholamines were unaffected. During prolonged distension, the effect on heart rate and cardiac index was transient. In conclusion, both gastric intubation and distension alter cardiovascular parameters, but the effect of distension undergoes rapid adaptation. Experimentally induced gastric distension is a valuable stimulus to study viscero-cardiovascular reflexes and their mechanisms using beat-to-beat measurements

Vascular Network Changes in the retina during ageing in normal subjects : a computerized quantitative study

BACKGROUND: Direct ophthalmoscopic examination of fundus oculi is widely used for the qualitative evaluation of target organ damage in several pathological conditions. At present, there are no reliable techniques available to quantify retinal vascular damage. The aim of this study was to develop a computerized technique for the quantitative analysis of fundus oculi. METHODS: We studied 68 non-smoking, normotensive normal subjects, with a visual acuity > 8/10. From each subject retinal images were taken using a non-mydriatic ophthalmoscope and digitized onto a personal computer. In each image the area of analysis was set to a circular selection, corresponding to 25% of the whole fundus oculi, concentric with the optic disc. From each selection arterial and venous area and mean arteriolar bifurcation angle were obtained. Measurements were taken in a blinded way by two operators and, by the same operator, twice at different times. Parameters were correlated with age and body surface area. RESULTS: Retinal arterial density (arteries 7.44 +/- 1.25%; bifurcation angle 75 +/- 16 degrees) was significantly correlated with age, but not with body surface area. Intra- and interobserver coefficient of variation resulted 2.5 and 3.2%, respectively. CONCLUSIONS: Computerized analysis of the fundus oculi with the evaluation of vascular density indexes represents a simple and reproducible technique that could be useful in identifying changes in retinal vascular network during ageing