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Biomedical subjects

L Leibnitz

Publications and source records attributed to L Leibnitz.

7 recordsLinked to original sources
PubMed1979

[Enzyme histochemical examinations of the visual system of the adult rat following unilateral enucleation].

12 adult white lab-rats were enucleated and after a survival period of 1, 3, 7 and 30 days the activities of GABA-T, GDH, LDH, SDH and GPDH were demonstrated histochemically in the Tractus opticus (To), Corpus geniculatum laterale, pars dorsalis (CGLd) et ventralis (CGLv), Colliculus superior (Cs) and Nucleus olivaris praetectalis (Nop). Since the ipsi- and contralateral grisea are always in the same tissue section the enzyme activities can be quantitatively compared by visual impression without a greater mistake. In To enucleation caused a hypertrophy of astrocytes together with an increase of the activities of GABA-T, GDH, LDH, and GPDH in these cells. The reactions indicate a more intensive metabolism in connection with the myelin degradation. In CGLd, CGLv, Cs and Nop following enucleation there appeared contralaterally a graded loss in the activities of GDH, LDH, GPDH, and GABA-T; only SDH scarely changed its activity. The fastest and strongest reaction was found in Cs and Nop, while CGLd and CGLv reacted later and to a less degree. In CGLv the enzyme reaction was limited to the lateral part of the nucleus. As diminution of activity is caused by degeneration of the retinal terminals the effected enzymes must be localised in cytoplasma and mitochondria of these terminals. Taking into account findings from literature the following is concluded from the time patterns, the degree of diminution of the enzyme activities and the relation of retinal to extraretinal terminals in the individual nuclei: GABA probably acts as a transmitter in interneurons of CGLd, Cs, and Nop. Glutamate is a transmitter in Cs and Nop.

4-Aminobutyrate Transaminase↗
PubMed1979

[Variability of the relay neurons in the corpus geniculatum laterale, pars dorsalis in the albino rat].

38 Golgi-impregnated relay cells from the Wistar rat's dLGN were investigated considering their possible differentiation into 2 types using camera lucida drawings with a magnification of 800. The following criteria were taken into account: 1. size of neurons (perikarya, size of dendritic domains) 2. structure of dendrites (number of dendrites, branching points, distribution of dendritic density in relation to the perikaryon, surface structures of dendrites). It was tried to correlate the investigated parameters quantitatively and qualitatively. The results showed that inspite of a missing clear subdivision into 2 types there exists a trend towards developing a second type of relay cells.

Animals↗
PubMed1978

[Axon-like glial extensions in the pars ventralis of the corpus geniculatum laterale (CGLv) of the albino rat].

In sections of the Corpus geniculatum laterale, pars ventralis (CGLv) of adult albino rats impregnated according to Golgi-Kopsch, structures are visible very similar to long unbranched axons with large boutons en passage. Within the CGLv these axon-like structures can be followed parallel to the optic tract. Generally they take a ventro-dorsal, exceptionally a dorso-ventral course. As well in Golgi-Kopsch material as in sections in which glial cells are specifically impregnated the described structures could be traced to cells mainly located subpial in the Tractus opticus. Within the optic tract these axon-like structures change their appearance looking similar as the numerous other processes originating from these cells too. These other processes take a course right-angled to the optic fibers and in general they don't bear axon-like structures as described. In our opinion based also on investigations of Nissl-stained sections the origination cells represent a specialized type of astroglia of until now unknown function.

Afferent Pathways↗
PubMed1975

[Problems and experience in the light optical and histological presentation of glia cells].

1. 8 histological techniques and 13 modifications derived from those were tested on usefulness for the demonstration of glial cells in the adult rat brain. From these methods the impregnation techniques of Golgi-Kopsch, Valenzuela y Chacón and Rio del Hortega were modified according to a scheme of variance to find out the optimal variants. 2. The impregnation quality depends on the animal species, the animal age, the health of brains, the brain area, the balanced proportion of the treatment stages and the biochemical state of the glial cells. 3. The silver impregnation techniques are not so specific that only one glial type is stained, but one type prevails. The silver carbonate procedure according to Hortega allows to impregnate oligodendrocytes, microglial cells and astrocytes in frozen as well as in paraffin sections. The method of Golgi-Kopsch is more suited for oligodendrocytes and microglial cells than for astrocytes. Following the procedure of Valenzuela y Chacón especially astrocytes, but also microglial cells allow impregnation in both frozen and paraffin sections. 4. The different demonstration qualities of the proved methods call for critical examination of absolute measurements of cell size, length of processes and ramification density. 5. The presence of cell groups of different disposition towards impregnation within a glial type speaks for a biochemical inhomogeneity of the glial types.

Animals↗