Functional properties of area 19 as compared to area 17 of the cat.

Out of a total of 139 area 19 cells, 87 were examined quantitatively for their responses to stimuli moving at a wide range of velocities. The results were compared with those obtained on a sample of 106 area 17 cells (out of a total of 172) tested in the same way. It was found that both areas 19 and 17 prefer slow stimulus movement. However, area 17 responded well to velocities up to 4 degrees/s while response amplitudes of area 19 cells started to decrease for stimulus velocities over 0.3 degrees/s. In both areas, responsiveness to fast stimuli improved at higher eccentricities. The most frequently encountered velocity type in area 19 was the 'velocity broad band' (VBB) type, lacking velocity preference, while the rarest type was the 'velocity tuned' (VT) type. As in area 17 very few area 19 cells were found to prefer high velocities (velocity high pass type, VHP) and those that were encountered had peripheral receptive fields (RFs). Cells preferring exclusively low velocities (velocity low pass type, VLP) were less frequent in area 19 than in area 17 and were considerably more sluggish. Area 19 was also less direction and orientation selective than area 17. In contrast, end-stopping was very common in area 19 (66%) and more units were binocular as compared to area 17. On average firing rate during optimal stimulation was lower in area 19 than in area 17. These results are consistent with the notion that area 19 receives predominantly W-type input and is involved in form discrimination (low spatial frequencies) during fixation.

Oxalosis in infancy.

Two cases of oxalosis in infancy are reported, the diagnosis and therapy are discussed and the world literature reviewed. Oxalosis in infancy is a rare condition, probably most frequently caused by a fulminant form of the autosomal recessive type I primary hyperoxaluria. It presents symptoms of renal failure in early infancy. This is progressive and usually causes death within three months after the onset of symptoms. The diagnosis can be suspected after simple procedures (abdominal roentgenogram, urinary tract ultrasonography) and confirmed by urine/plasma analysis and kidney biopsy/bone marrow aspiration. An exact diagnosis is important since it has consequences concerning genetic counseling and treatment. Dialysis and transplantation may be useful in secondary oxalosis, but until now they are hard to justify in infantile primary oxalosis. In primary hyperoxaluria (type I), pyridoxine therapy gives hopeful results before the onset of oxalosis, but unsatisfactory results after the onset of oxalosis.

A senescent pattern of pituitary function during critical illness and dopamine treatment.

Human critical illness is characterized by protein hypercatabolism, preservation of fat depots and by immune dysfunction. Optimized parenteral or enteral feeding and other advanced, supportive therapies remain unable to prevent ensuing wasting of vital organs and muscles and deficient healing processes. The anterior pituitary gland is a prime regulator of human metabolism and immune function through the orchestrated secretion of hormones, including growth hormone, thyrotropin, gonadotropins, prolactin and corticotropin. Except for the latter hormone, the releasing activity of the pituitary tends to decrease with advancing age and this decline is thought to be one of the mechanisms underlying the gradual loss of anabolic drive, reparative processes and cellular defence in senescence. In this work, critical illness was documented to be consistently associated with a diminished level of activity in the different axes governed by the pituitary, except for the corticotropic axis. In addition, this aging pattern of pituitary function in critical illness was found to be aggravated by the infusion of dopamine, a common practice in intensive care medicine for newborns, children and adults. The latter observation launches the hypothesis that endogenous dopamine may participate in the pathogenesis of the pituitary dysfunction in critical illness. Finally, these findings establish a base to explore the therapeutic potential of pituitary hormones and their secretagogues to enhance recovery from severe illness.