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Biomedical subjects

J Fent

Publications and source records attributed to J Fent.

8 recordsLinked to original sources
PubMed2001

Right prefrontal activation produced by arterial baroreceptor stimulation: a PET study.

This study was performed to test the hypothesis of greater right hemispheric involvement in the processing of baroreceptor stimuli. Carotid sinus baroreceptors were stimulated by rhythmically decreasing air pressure in a neck chamber, and under control conditions the thorax was stimulated in a similar manner. Changes in regional cerebral blood flow (rCBF) were measured by PET. Baroreceptor stimulation resulted in rCBF increase in the right anterior-inferior prefrontal cortex (Brodmann areas (BA) 10/44/47) and bilaterally in BA 6/8. We conclude that in at least some stages of baroreceptor information processing the right hemisphere plays a greater role than the left hemisphere.

Adolescent↗
PubMed2001

[Role of the monocye-lymphocye system and of endogenous mediators in the severity of acute pancreatitis and in development of its septic complications].

The activity of monocyte/lymphocyte system and the splanchnic circulation was investigated in acute pancreatitis. The splanchnic blood flow was characterised indirectly by gastric intramucosal pH changes, which strongly correlated with APACHE-II score, and predicted the bad prognosis. The high CD14/HLA-DR and CD14/CD16 coexpression, the low TNF-alpha production proved to be unfavourable prognostic factor in the early phase of the disease. The expression of IL-2, IL-10 and moderately of IL-4 was elevated, but the expression of INF gamma did not show significant alteration. The thrombocyte aggregation decreased in the early phase. There are bad prognostic signs if its level remains constantly low and ATP-release increases. The activity and index of phagocytosis were higher in comparison with controls, but these parameters were not increasable with higher cell concentration. The ROI production increased, and the increase in the fMLP and o'zymosan indicated LDCL seems to be unfavourable prognostic sign, which well correlated with the APACHE-II score.

Acute Disease↗
PubMed1999

An attempt for the application of the basic Law of Psychophysics (Fechner-Stevens Law) in the domain of visceral stimuli in humans.

The validity of the basic Law of Psychophysics proposed originally by Fechner and revised by Stevens had been tested in the domain of visceral perception. The experiments were carried out on six adult colonostomy patients. The distension of the sigmoid colon (the phi-value of the Fechner-Stevens equation) had been undertaken by the aid of a rubber balloon inserted into the intestinal stoma orifice and controlled by a computerized pneumatic system. The tracking of sensations of "gut-feelings" by the subjects (the psi-value of the Fechner-Stevens equation) had been made possible by applying the subjects' manipulation of a sliding potentiometer of a Visual Analogue Scale (VAS-device). The results seem to prove the extension of the validity of the Fechner-Stevens power equation to the field of visceral perception.

Adult↗
PubMed1999

Visual event-related potentials evoked by using a virtual reality display.

This study aimed at investigating whether a virtual reality display (VRD) is an appropriate tool for evoking visual event-related potentials (VEPs). VEPs evoked by VRD stimuli were highly similar in form to VEPs evoked by using a computer monitor, both having two dominant peaks, labeled P100 and N200. Monitor and VRD N200 latencies and amplitudes were highly correlated. However, peak latencies were longer and the peaks were broader when stimuli were presented on the VRD. Besides, VRD P100 amplitude was smaller, and an N75 peak could be seen usually only on monitor VEPs.

Adult↗
PubMedDate not supplied

Colonic sensitivity in irritable bowel syndrome and normal subjects according to their hemispheric preference and cognitive style.

According to our earlier results, non-painful, weak afferent visceral signals may exert a steady influence on brain processes, including cognitive functions. In the present series colonic impulses of irritable bowel syndrome (IBS) subjects served as a model of chronic impact from the gut. Hemispheric preference, as well as cognitive style of information processing served as indicators of covert changes in brain functions. In twenty-one IBS patients and in ten control subjects of both sexes, the thresholds of minimal colonic distension sensitivity has been measured following the determination of hemispheric preference and of advantage in verbal or spatial information processing of the subjects. In IBS patients distension thresholds proved to be higher in verbals than in spatials, whereas in healthy controls the relationship of colonic thresholds and verbal versus spatial advantage was reversed. Among the normal controls with left hemisphere preference a significantly higher distension threshold has been observed than in those with right hemisphere preference, whereas in the IBS group such threshold-differences were not observable.

Adult↗