Automatic registration of retina images based on genetic techniques.

The aim of this paper is to develop an automatic method for the registration of multitemporal digital images of the fundus of the human retina. The images are acquired from the same patient at different times by a color fundus camera. The proposed approach is based on the application of global optimization techniques to previously extracted maps of curvilinear structures in the images to be registered (such structures being represented by the vessels in the human retina): in particular, a genetic algorithm is used, in order to estimate the optimum transformation between the input and the base image. The algorithm is tested on two different types of data, gray scale and color images, and for both types, images with small changes and with large changes are used. The comparison between the registered images using the implemented method and a manual one points out that the proposed algorithm provides an accurate registration. The convergence to a solution is not possible only when dealing with images taken from very different view-points.

Evaluation of circulating galanin levels after exercise-induced pituitary hormone secretion in man.

The neuropeptide galanin (GAL) is widely distributed in the central and peripheral nervous systems, anterior pituitary, and adrenal medulla. GAL is colocalized with corticotropin (ACTH) in the human pituitary and with epinephrine (E) and norepinephrine (NE) in chromaffin cells of the adrenal medulla. The function of GAL in peripheral tissues is not known, although the presence of the peptide in corticotrophs and the adrenal gland suggest that it participates in stress responses. In the present study, we investigated whether GAL is cosecreted with ACTH during activation of corticotrophs by an acute physical exercise test. Circulating levels of GAL and pituitary hormones were measured in healthy exercise-tested and control male subjects. Blood samples were collected during basal conditions, maximal power output (MPO), and the recovery period. Control subjects were sampled during the resting condition. The pituitary response to exercise was characterized by a significant increase in ACTH plasma levels (peak value 13.28 +/- 2.19 v 6.68 +/- 1.01 pmol/L, P < .05) and growth hormone (GH) serum levels (peak value, 14.53 +/- 5.59 v 0.29 +/- 0.1 microg/L, P < .02), with the peak in hormone levels detected 15 minutes after the end of exercise. No change in circulating prolactin (PRL) levels was detected. An expected significant increase in plasma levels of both E (peak value, 1,574.41 +/- 403.31 v 267.44 +/- 60.03 pmol/L, P < .01) and NE (peak value, 7,275.25 +/- 955.80 v 961.51 +/- 168.40 pmol/L, P < .01) was also observed. Plasma GAL levels were not affected by the acute exercise test, with the levels being comparable to baseline during the exercise test and the recovery phase. At any sample time, GAL values were comparable between exercise-tested and control subjects. These data show that despite the colocalization of GAL and ACTH within the same pituitary cells, the two peptides are not coreleased in response to stress resulting from acute physical exercise. Furthermore, pituitary GAL seems not to be involved in the stimulation of GH secretion in exercise-tested subjects. The results also indicate that GAL is not coreleased with E or NE in response to the exercise-induced stress condition.

Concomitant evaluation of plasma galanin and catecholamine levels during a cold pressor test in healthy human male and female subjects.

The neuropeptide galanin (GAL) is localized in the peripheral and central nervous systems as well as in the adrenal medulla where it coexists with catecholamines. We evaluated the changes in GAL plasma levels as well as systolic and diastolic blood pressures and in the plasma levels of epinephrine and norepinephrine (NE) in normal human male and regularly menstruating female subjects during the activation of the sympathoadrenal system by a cold pressor test. The test was performed by immersing the hand of the subject in 1 degree C cold water for 4 min. Blood samples were collected both under basal conditions and at subsequent intervals during the cold stimulus as well as at the end of the recovery phase. The values were compared with those obtained when the same subjects were sham tested. As expected, systolic and diastolic blood pressures increased in both sexes during the cold test; the systolic blood pressure values were significantly (p < 0.05) higher in males. Epinephrine and NE levels rose significantly above baseline in both male and female subjects after the cold stimulus; the NE increments were significantly (p < 0.05) higher in males. The basal GAL levels were found to be variable but not sexually dimorphic. In both sexes, during cold stimulus and recovery phase, GAL values were found to be not significantly different from those detected during the sham test. These results demonstrate that the release of GAL in peripheral blood is not associated with that of catecholamines in response to the cold pressor test.