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Biomedical subjects

G Hamdorf

Publications and source records attributed to G Hamdorf.

11 recordsLinked to original sources
PubMed1996

[The structure of the stellate sympathetic ganglia under long-term hypoxia].

Changes of mitochondrial ultrastructure indicating not only degenerative processes but also the presence of organelle adaptive reactions were demonstrated in sympathetic neurons. Appearance of osmiophilic inclusions in mitochondrial matrix relates to most typical organelle alterations in ageing. Number of smooth endoplasmic reticulum vesicles equal in size to synaptic vesicles of nerve cells processes grows higher. Such vesicles are usually located near postsynaptic active zones and areas with neuronal plasmolemma free from glia. Their outward resemblance does not allow to claim that neuromediators and neuromodulators may turn up in these vesicles, although dendrites contain and may release certain biologically active substances. Basic difference between 24 and 30-months old rats lies in earlier degenerations of nerve cells in old animals. Forming of dark granules may be also associated with conditions of fixation. Small granular (SG) cells lacked typical lipofuscine granules, while their ultrastructure changed insignificantly. SG cells capacity to divide mitotically in functional maturity is likely to be one of the possible explanations of such difference.

Aging↗
PubMed1992

Irradiation neurotoxicity assessed in organotypic cultures of rat hippocampus.

The neurotoxic effects of irradiation on the developing nervous system were studied in organotypic cultures of hippocampus prepared from newborn Sprague-Dawley rats. Hippocampus slices of 7-day-old rats were irradiated at the day of explantation at doses of 1, 2 and 4 Gy, and cultured in a roller drum for a fortnight. Light and electron microscopy showed remarkable damage to neuronal cells following irradiation, oligodendrocytes and myelogenesis being also affected. In contrast to alterations in neuronal perikarya, no morphological changes in synapses were obvious, though their number seemed to be reduced after irradiation with 4 Gy. These results confirm that low dose radiation produces damage to the central nervous system not only pre-natally, but even in post-natal periods of differentiation and development.

Animals↗
PubMed1992

Increase of survival time in experimental hypoxia by cytidine diphosphate choline.

36 Wistar rats were kept in chronic hypoxic hypoxia of 7 vol % of oxygen in 2 experiments over a period of 6 months, other 36 served as controls. Half of the animals of each group received cytidine diphosphate choline (CDP-choline, citicoline, Somazina; CAS 987-78-0) at a dose of 100 mg/kg body weight in the liquid food. Animals in chronic hypoxia without application of CDP-choline developed pathological symptoms and began to die after 19 to 23 weeks in hypoxia. Rats that received CDP-choline developed less prominent pathological symptoms and died later or remained alive until the end of the experiment. Under conditions of extreme hypoxia CDP-choline exhibited a life-prolonging effect.

Animals↗
PubMed1991

Brain changes in experimental chronic hypoxia.

A model of normobaric hypoxia was developed in which adult female cats were exposed to decreasing amounts of oxygen (21, 15, 10, 8, 7, and 5 vol.%) over a period of 320 days. Blood flow as well as the blood flow responses to changes of pCO2 were depressed in both cerebrum and cerebellum. These decreases were more severe in the cerebellum. The metabolic rate for oxygen was also depressed. A decrease in the Purkinje cell number was evident. A different degree of damage was observed in the top, the intermediate and the bottom region of the cerebellar gyri. Microvascular proliferation occurred in the whole brain.

Animals↗
PubMed1991

Therapeutic effect of orally applied cytidine diphosphate choline in mild and severe degrees of normobaric and normocapnic degrees of hypoxia of rats.

Eighty Wistar rats were maintained under conditions of chronic hypoxic for a period of 5 months. After gradual adaptation to the reduced oxygen content of the inhaled air, animals were kept on the levels of 15, 12, 10 and 7 vol% O2 and their behaviour in an open field was observed. One group of 40 animals received CDP-choline (cytidine diphosphate choline, Somazina; CAS 1477-47-0) at a dose of 100 mg/kg body weight in their food. Hypoxia-induced behavioural deteriorations were partly mitigated by this substance. Therapeutic application of CDP-choline was more effective than prophylactic administration. The efficiency of CDP-choline decreased after prolonged application. Under conditions of extreme hypoxia CDP-choline exhibited a life prolonging effect.

Administration, Oral↗
PubMed1990

Morphological changes in cultures of hippocampus following prenatal irradiation in the rat.

The effect of prenatal irradiation was studied in organotypic cultures of hippocampus, prepared from newborn rats that had been exposed to whole-body irradiation of 1 Gy from a 60Co-source at day 13 of pregnancy. Light and electron microscopic observations showed remarkable damage to neuronal mitochondria accompanied by extensive swelling, vacuolation of the Golgi complex, and formation of multilamellar bodies and vesicles of the lysosomal type. In contrast to neuronal alterations, no delay in synaptogenesis or onset of myelination was observed based upon the absence of significant morphological changes in synapses and myelin sheaths. Using this tissue culture model it could be confirmed that prenatal exposure to irradiation, even at low doses, induces specific morphological changes in the brain.

Animals↗
PubMed1990

Selective adherence of neurons and glial cells from dissociated cerebral and spinal cord microcarrier cultures.

In stationary cultures of dissociated brain and spinal cord grown on microcarriers (MCs), the neuronal and ependymal cells attached to the MCs forming floating aggregates in which they grow in a three-dimensional pattern. The glial and meningeal elements on the contrary, tend to dissociate from the aggregates and adhere to the plastic dish where they divide to form a monolayer. This different behavior of CNS components is not observed in rotating cultures in which all CNS cells remain attached to the MCs and develop into mature floating structures. This cell separation in stationary MC-cultures which is documented here by SEM and immunocytochemistry, may be useful for analysis and evaluation of the metabolic biochemical events of each of the cellular components derived from the same culture.

Animals↗
PubMed1990

Study of the effects of oral administration of CDP-choline on open-field behaviour under conditions of chronic hypoxia.

48 Wistar rats were maintained over a period of 103 days while the oxygen content of the air was continuously reduced. Their behaviour in an open-field was observed at each step of oxygen deficiency (15, 12, 10, 8 and 7% O2 inspiratory). One group (24 animals) was given CDP-choline (cytidine diphosphate choline, Somazina) at a dose of 100 mg/kg body weight administered by addition to the food. Behavioral reactions indicative of deterioration in vigilance were recorded under hypoxic conditions. CDP-choline showed a protective effect increasing vigilance under mild (15% O2) hypoxia, indicating the possibility of treatment of patients with cerebral syndromes secondary to hypoxia.

Administration, Oral↗