摘要:

Female albino rats were exposed during 3 weeks to various photoperiodic sequences and levels of illumination. As long as the light span of the photoperiod did not exceed 12L-12D, the damaging effects of the light, even when intense (3,000 lx), on the retinal were relatively limited. On the other hand, the 14L-10D photoperiodic regimen that is usually used in standard rat animaleries produced marked degenerative lesions on the photoreceptors under either 1,200 or 3,000 lx. Under lighting schedules of 21L-15D or 28L-20D, the photoreceptors were heavely injured by 1,200 or 3,000 lx. The degenerative process affected all the photoreceptive cells as well as their various components: rods, cones, nucleus and synaptic endings.

ISSN:1422-6405    

DOI:10.1159/000144750

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Scanning electron microscopy has been used in order to provide the morphological study including comparative measurements of the main parts of the Baboon spermatozoon. If the dimensions of the head and the mid-piece are fairly close to the human spermatozoon, the Baboon spermatozoon is practically twice as long as the human one. In the Baboon spermatozoon, the head appears smooth with only a light transversal furrow at the level of its posterior third, which probably marks the limit of the posterior border of the equatorial segment. The mid-piece, a conical trunk, is larger in its anterior part than at the level of its posterior extremity. The end-piece appears very short as compared with the total length of the sperm cell. The technical modalities of the preparation and the possibility of artifacts are briefly discussed.

ISSN:1422-6405    

DOI:10.1159/000144751

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Here we present a statistical study of the finding of Paneth’s cells in the human vermiform appendix and their relation to age and sex of the patients. These cells appeared in 95.5% of the cases which were studied, existing a predominance for the masculine se

ISSN:1422-6405    

DOI:10.1159/000144752

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Compressive forces are greater at the rat mandibular joint during incising. Studies of histological sections taken from the mandibular joints of serially sacrificed rats with (a) the incisors removed, (b) the incisors trimmed, (c) the incisors trimmed to the age of 40 days only and (d) normal controls suggest that compressive forces at this joint are necessary to stimulate normal cartilage development.

ISSN:1422-6405    

DOI:10.1159/000144753

出版商:S. Karger AG    

年代:1977

数据来源: Karger