Hans G. P. Jansen

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In the retina of mice homozygous for the retinal degeneration slow (rds) gene, receptor outer segments failed to develop and typical disc structures were never observed. However, cilia surrounded by a plasma membrane were regularly present. At the time when outer segments grew in the normal retina, the optic ventricle in the mutant showed an accumulation of(More)
Mice homozygous for the rds (retinal degeneration slow) gene fail to develop receptor outer segments and show a slow loss of visual cells that starts from 14-21 postnatal days and results in complete absence at 1 year. In the heterozygous rds/+ mice the development of receptor outer segments is initially retarded. Although a distinct layer of outer segments(More)
In order to describe the morphology of dendritic spines of identified neurons in the cat inferior olive together with their gamma-aminobutyric acid (GABA) synaptic input, a technique was used combining intracellular labeling of horseradish peroxidase with postembedding gold-immunocytochemistry. With this technique physiologically identified olivary cells(More)
In normal retina the developing photoreceptor cells first show presence of opsin over the distal ends of the ciliary protrusions. In a fully differentiated cell intense activity is seen over the rod outer-segment discs; some activity is also seen over the Golgi zone and near the distal ends of the inner segments but the other parts of the receptor cell(More)
In mice homozygous for the newly reported rds (retinal degeneration slow) gene, a progressive loss of visual cells occurs throughout life. Histogenesis of the retina proceeds normally with the exception of the receptor layer which remains rudimentary. Electron microscopic observations of the retina at different stages of development have revealed that the(More)
The rudimentary eyes of the mole rat (Spalax ehrenbergi) are located under the skin and do not respond to light stimuli. However, removal of the eyes disturbs photoperiod perception in these animals. To help clarify the possibly remaining function of the eyes in this species, the authors studied their development and ultrastructure. In the early embryos the(More)
In the retina of mice heterozygous for the retinal degeneration slow gene (rds/+) the photoreceptor cells, both rods and cones, develop abnormal outer segments but establish normal synaptic contacts. The other retinal layers also show normal structural organization. Starting from the age of 2 months, a very slow loss of photoreceptor cells progresses(More)
In the retina of chimaeric mice of rd and wild-type genotypic combination, selective loss of rd/rd photoreceptor cells, after initial development, leads to a mosaic retina with variable amounts of normal photoreceptor cells present over the retinal surface. In some of the rod terminals of these retinas the synaptic complexes with the second order retinal(More)
Albino mice were exposed to constant light for 7 days and were then transferred to periodic light. After initial photic damage and partial cell loss, the remaining visual cells recovered and survived as a stable population. Regions of the outer nuclear layer containing 4-6 rows of nuclei were more affected than those containing 6-10 rows. Changes in the(More)
Following partial loss of photoreceptor cells in the retina of mice afflicted by mutant genes, damaging light exposure, or old age, some of the remaining rod cells exhibited a process of growth in their synapses with the second order retinal neurons. This growth was recognized by the presence of multiple synaptic sites in some of the rod terminals in the(More)