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Biomedical subjects

G Lindner

Publications and source records attributed to G Lindner.

At least 55 records · Page 3Linked to original sources
PubMed1986

Hemorheology in biofiltration and acetate dialysis (preliminary results).

Hemorheological measurements were made in 8 stable chronic haemodialysis patients observed in conventional acetate dialysis (AD) with Cuprophan membrane and then in biofiltration (BF) with PAN AN69S membrane. Blood viscosity diminished at the beginning, both during BF and AD, reaching pre-dialytic values again at the end of treatment. Blood and erythrocyte filtration increased after 20 min in AD and throughout the session in BF. Preliminary results suggest an improvement of hemorheological parameters during dialytic treatment, more notable in BF than in AD.

Acetates↗
PubMed1986

[Scanning electron microscopy and light microscopy studies on the retina of chick embryos in cell culture].

Histological and scanning electron microscopy studies (SEM) suggest a classification of neural elements into five main types: receptor cells, bipolar cells, horizontal, amacrine, and ganglion cells in dissociated cell cultures of the retina from 7 to 10 days old chick embryos. By use of SEM the development of the receptor cell inner segments was observed. At the same time many protrusions were noticed at the receptor cell surface. Specific synaptic contacts between the axons of the receptor cells and the dendrites of the bipolar neurons, as well as unspecific contacts between the pericarya of the receptor cells and other dendrites were demonstrated. The bipolar neurons showed smooth cell surfaces, however, the horizontal cells appeared rough on the cell surfaces. Müller cells were always found adjacent to the photoreceptor cells.

Animals↗
PubMed1984

[The effect of N and C terminal sequences of substance P on non-neuronal cells in vitro (nerve tissue culture)].

The effect of peptides (SP1-2, SP3-4 and SP5-11) of substance P (SP1-11) on the morphology of the areas of growth of explants of the ganglion trigeminale from chick embryos after incubation in Maximow chambers was observed. N- and C-terminal sequences effected the growth of cultures differently. In dipeptide-treated (= N-terminal sequences) cultures the areas of growth increased. In heptapeptide-treated cultures (= C-terminal sequence SP5-11) the areas of growth decreased. Only the dipeptide SP3-4 effects a mitogenic effect on nonneuronal cells in short time tests. The C-terminal sequence SP5-11 stimulates neither the growth of nerve fibres nor the proliferation of cells. Finally the importance of this in-vitro-tests in relation to the in-vivo-situation is discussed.

Animals↗
PubMed1983

[Morphological studies of the effect of substance P partial sequences on nerve tissue culture].

Explants of the telencephalon and of the ganglion trigeminale from chick embryos were cultivated in the presence of 10(-7) M of substance P partial sequences SP 1-2 (Arg-Pro . 22HCl) and SP3-4 (Lys(Z)-Pro . HCl or Lys-Pro . 2HBr). The morphology of the living outgrowth in fact the growth of nerve fibers, cell migration and proliferation was observed. SP1-2 and SP3-4 influenced particularly the morphology of pns cultures.

Animals↗
PubMed1982

[The effect of substance P (SP) and SP partial sequences on nerve fiber growth in tissue culture].

Explants of the ganglion trigeminale (PNS) and of the telencephalon (CNS) from chick embryos were cultivated in MAXIMOW chambers in semisynthetic media in the presence of dipeptide fragments (Lys(Z)-Pro . HCl, Lys-Pro-2HBr, Arg-Pro-2HCl) and the heptapeptide (SP5-11) of substance P as well as the complete substance P (SP1-11). 1. Histological examination of the dipeptide-treated CNS explants indicates that the structure of outgrowth in vitro is changed. Fascicel were observed. A stimulation of nerve fibre extension did not take place. 2.1. In dipeptide-treated PNS cultures the index of areas covered by the explants increased. 2.2. The index of nerve fibre growth increased significantly. The stimulation was caused in multiplication of fibres. Only Lys(Z)-Pro . HCl presents a prolongation of neurites. 2.3. SP5-11 effects in no case the growth of nerve fibres. SP1-11 stimulated significantly the fibre regeneration. 3. The possible role of SP1-11 with different effects under in vitro conditions is discussed. Only the N-terminal dipeptides stimulate the growth of nerve fibres. The C-terminal SP5-11 is without effect. Finally it is stated that the best results in neuritic enlargement and neurogenesis can only be obtained by cultivation with SP1-11.

Animals↗
PubMed1982

[Morphometric studies of the rat hippocampus after static and dynamic cultivation].

Explants of the hippocampus (rat) were cultivated either in maximow chambers without movement (static) or in movement (dynamic) by rotation in roller tubes. The growth of nerve fibres, the density of cells (matrix, neurons) and the area of cell nuclei was observed. The determination of the index of nerve fibre growth, the procedure for counting cells in a tissue with different densities and the value of the two methodological approaches of cultivation is discussed. Finally it is stated that best results in morphology of explants can only be obtained by cultivation without movement.

Animals↗
PubMed1982

[Effect of the culture technic on the development of the hippocampus (rat) in vitro].

150 hippocampal explants from fetal and neonatal rats were cultivated with semisynthetic media in maximow chambers without movement and in roller tubes by rotation in the virutor up to 3 days. The cultures were fixed in Bouin, cuted 15 microns and coloured with the method of Klüver-Barrera or haemalaun. Histological examination of the explants revealed that hippocampi cultured in maximow chambers without movement possess an organisation similar to that observed in situ. Experiments with rotated explants of hippocampus indicate that the structure of hippocampus in vitro is changed. Especially neurons are degenerated and the migration of cells is altered. Finally the value of these two methodological cultivations for neurobiology is discussed.

Animals↗
PubMed1981

[The effect of substance P on the regeneration of nerve fibres in vitro (author's transl)].

Explants of the ganglion trigeminale from chick embryos (PNS) and of the hippocampus from fetal rats (CNS) were cultivated in maximow chambers in the presence of synthetic substance P (SP). SP Stimulated the outgrowth of neuronal processes in PNS-culture. In SP-treated CNS cultures a stimulation was not observed. The density of SP-treated medio-dorsal neuroblasts decreased. The possible role of SP as a system in controlling in-vitro-processes of nerve fibre regeneration is discussed.

Animals↗
PubMed1981

[Effect of substance P on the ganglion trigeminale in tissue culture (author's transl)].

Explants of the ganglion trigeminale from chick embryos were cultivated in Maximow chambers in the presence of 10-6...10-8 M substance P (SP . 3CH3COOH.4H2O). 1. In SP-treated cultures the index of areas covered by the explants was increased in shorttime tests. 2. The density of cells was related to the type of medio-dorsal (MD) and ventro-lateral (VL) neuroblasts. The density of SP-treated VL cells was not altered. The density of MD cells decreased. 3. The percentage of dark neuroblasts was decreased under the influence of SP. 4. A stimulation of VL neuroblasts did not take place. 5. The diameters of MD pericarya and the areas of MD cell nuclei and the areas of nuclei from nonneuronal cells increased. 6. The possible role of SP as a factor controlling In-vitro-processes is discussed.

Animals↗
PubMed1981

[The development of nervous tissue to experimental manipulation in vitro (author's transl)].

Explants of nervous tissue (CNS: hippocampus from fetal rats, telencephalon and PNS: ganglion trigeminale from chick embryos) were cultivated in maximow chambers. Biological extracts (brain and embryo extract) or chemical agents (aminoacid mixtures and peptides with known sequence of amino acids) were tested. Biological extracts and aminoacid mixtures stimulated the differentiation in PNS and CNS cultures. A stimulating effect of peptides seems to exist only on PNS explants. The fundamental importance of suitable reference systems, parameters, optimal concentrations and periods of application of effective substances for the evaluation of the results is discussed.

Amino Acids↗
PubMed1980

[Effect of substance P on nerve fiber regeneration in tissue culture].

Explants of the ganglion trigeminale from chick embryos (PNS) and of the hippocampus from fetal rats (CNS) were cultivated in maximow chambers with growth medium or maintanance medium. Varied concentrations of substance P (SP . 3 CH3COOH . 4 H2O) were added. 1. The effect of substance P (SP) is related to concentration. In the presence of 10(-7)M SP in the growth medium and of 10(-4)M SP in the maintanance medium the cultivation of PNS cultures indicates positive results. These doses are suitable. 2. Within the first 24 hours in vitro SP stimulates the index of area in PNS cultures. The index of characterizes the relation of the outgrowth zone to the explant. In CNS cultures a significant difference of this effect was not observed. 3. The index of growth of nerve fibers may compare the test cultures with the control cultures. SP significantly increases the index of fiber growth in PNS cultures. A stimulation of CNS cultures was observed, significance was not found. 4. From the beginning of the cultivation with SP up to 48 hours in vitro the growth of nerve fibers significantly increases in the treated cultures in comparison with the control cultures. After this time the growth of nerve fibers decreased and a morphological conformity of test cultures and controls was observed. 5. The role of SP is discussed in specific activity on PNS tissue in vitro. The reactive neurons may be from the medio dorsal group of cells of the sensible ganglion.

Animals↗
PubMed1980

[The effect of active substances on nerve fiber regeneration in nerve tissue cultures].

Explants of the ganglion trigeminale from chick embryos and hippocampi from embryonal rats were incubated in maximowchambers with semisynthetic media. The different parts of nervous tissue were influenced experimentally by addition of biological extracts and by substances with known composition. The regeneration of nerve fibers was investigated by the index of growth. The growth index was calculated from the ratio of nerve fibre index of the test cultures to that of the influenced cultures. Under these conditions biological extracts enhanced the growth of nerve fibres. In the same way the growth of nerve fibres was statistically significantly stimulated by substances with known composition of aminoacids, orotic acid, sodium orotate and cyclic monophosphates. A stimulating effect of cyclic guanosinmonophosphate seems to exist only in CNS explants and only in young fetal rats and consists in an increased migration and proliferation of cells as well as in the formation of fibres from neuroblasts. The investigations gave strong evidence for the in vitro testing to be very useful in studies of nerve fibre regeneration. However the choice of suitable reference systems, suitable quantitative parameters, optimal concentration and periods of application of effective substances and the age of the animals are of fundamental importance for the evaluation of the results. Experiments regarding the stimulation of the differentiation of neurons and the growth of nerve fibres are of practical clinical and therapeutical interest.

Animals↗
PubMed1980

[The effect of orotic acid and sodium orotate on organ cultures of the hippocampus of embryonic rats].

Organ cultures of hippocampus from fetal rats were cultivated in Maximow chambers with semisynthetic media up to 12 days in vitro and fixed after 1, 5 and 12 days in culture, cuted 15 micrometer and coloured with the method of Klüver-Barrera. The effect of 5 x 10(-6) M sodiumorotate and 6 x 10(-6) M orotic acid was tested. 1. The density of cells is related to the zone of cells, the drug and time of incubation. 2. The density of cells increased in the zone of matrix after application of sodiumorotate and orotic acid. The density of cells significantly decreased in the migration zone. The density of neurons significantly increased in the region CA 3. 3. Orotic acid and sodiumorotate influenced the migration of cells in vitro. Sodiumorotate stimulated migration and differentiation. Longtime cultured hippocampi degenerated in vitro after influence of orotic acid. 4. The area of nuclei from neurons increased up to 12 days in vitro, when the cultures were tested with sodiumorotate. Only within the first 24 hours orotic acid effected an increase of the area of nuclei from matrix cells. It is discussed, sodiumorotate influenced in vitro metabolic processes in suitable systems.

Animals↗