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Biomedical subjects

G Horn

Publications and source records attributed to G Horn.

At least 145 records · Page 8Linked to original sources

Amnesic effects of intravenous diazepam and lorazepam.

The amnesic effects of 2 benzodiazepine drugs, diazepam (Valium) and lorazepam (Ativan), have been investigated. Some of the effects were similar to those of certain clinical amnesic syndromes. The effects were more extensive than previous work has indicated.

Adult↗

Responsiveness of neurones in the hippocampal region of anaesthetised and unanaesthetised cats to stimulation of sensory pathways.

The responses to sensory stimuli and to shocks to the optic pathways have been studied for 399 units in the hippocampal region of 19 cats. 172 units were recorded from anaesthetised cats and 229 from 7 unanaesthetised cats. In the unanaesthetised animals the proportions of units responding were high (60%) and did not differ significantly between regions for each type of stimulation investigated: visual, auditory and optic chiasma shocks. The proportion of units responsive to chiasmatic stimulation was related to the background firing rate. The latencies and duration of the responses were relatively long and variable. Both increases and decreases in responsiveness occurred. In a number of units response were erratic, sometimes being brisk and at other times totally absent. Responses during one series of stimuli were not always similar to those during a subsequent series. A higher proportion of units responded decrementally to a series of sensory stimuli than to a series of shocks to the optic chiasma. Movement by the animal was wihtout consistent effect on unit activity. Responses were markedly influenced according to whether or not the cat looked intently at an object. An important determinant of HR unit responses was the state of arousal, the effect being regionally distributed. In anaesthetised animals the proportions of responding units were substantially lower and the responses were weaker than those in the unanaesthetised cats.

Anesthesia, General↗

Effects of LSD on the response of single units in cat visual cortex.

The effects of intravenous doses (200 mug) of LSD on the activity of single neurones in the primary visual cortex have been studied in cats anaesthetized with urethane. Cells were stimulated with a bright bar of light moved over the receptive field, and orientation tuning was assessed quantitatively before and after administration of the drug. Changes in neuronal activity were compared with those observed in a control sample of cells recorded when the cats were given no drug. LSD increased the responsiveness of some cells to visual stimuli and decreased that of others, but some cells were not affected. The changes in responsiveness were dose dependent; the larger doses of the drug (expressed in mug/kg body weight) tended to depress the responses and the smaller doses to enhance them. The effects appeared earlier in complex cells than in simple cells. Changes in spontaneous activity, direction selectivity and orientational properties were found in some cells.

Animals↗

[Gestagen therapy in bladderneck adenoma. III. Clinicochemical findings and course controls in patients with bladderneck adenomas under gestagen therapy].

It is reported on clinico-chemical examinations in 30 carriers of adenomas, who underwent a gestagen therapy lasting 3 months. The treatment was performed in group I in 15 patients with progesterone depot and in group II with depostate. After the end of the treatment in group I an increase of the content of the sodium ions was found. The infections of the urinary tract improved. Neither in negative sense nor in positive sense an influence of the therapy on the other examination parameters was found.

Adenoma↗

Isolation and identification of the conidial germination factor of Neurospora crassa.

The germination-essential substance (germination factor [GF]) that is lost from conidia of Neurospora crassa on exposure to solutions of low water activity has been isolated and identified as a group of iron-transport compounds, or siderochromes. The principal siderochrome of conidia is ferricrocin, a cyclic hexapeptide. A closely related substance, ferrichrome C, is tentatively identified as a minor constituent. The same substances are also present in extracts of mycelium along with small amounts of a third siderochrome, which has not been identified. The GF activity of culture filtrates is due to coprogen, the only siderochrome previously identified with N. crassa.

Chemical Phenomena↗