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Biomedical subjects

G Hinz

Publications and source records attributed to G Hinz.

At least 37 records · Page 2Linked to original sources
PubMed1985

Molecular forms and subunit structure of the acetylcholine receptor in the central nervous system of insects.

The nicotinic acetylcholine receptor as probed by alpha-bungarotoxin binding has been isolated from detergent-solubilized ganglionic membrane preparations from the insect, Locusta migratoria. The isolation and characterization of the receptor protein was achieved by preparation of membrane fragments, extraction by sodium deoxycholate, centrifugation on sucrose density gradient, affinity chromatography, gel electrophoresis, and immunoblotting. The purified receptor protein migrated as a single band on polyacrylamide when native (Mr = 250,000 to 300,000) but also under denaturing conditions (Mr = 65,000) and cross-reacted with some monoclonal antibodies against the Torpedo receptor. In immunohistochemical approaches using polyclonal antibodies the acetylcholine receptor antigenic sites could topochemically be identified at very distinct zones in the neuropil of locust ganglia. The results suggest that the acetylcholine receptor in the central nervous system of insects represents an oligomeric complex composed of four identical or very similar subunits and thus may represent a prototype of the recently proposed homo-oligomeric ancestral acetylcholine receptor.

Animals↗
PubMed1983

Increased radioresistance of cells in cultured multicell spheroids. II. Kinetic and cytogenetic studies.

Using the Chinese hamster cell line B14 FAF28, several specific properties of the contact effect (CE) of radiation action in spheroids were investigated. CE was found to "protect" the spheroid cells against several types of radiation-induced cytogenetic misfunctions such as blockage in S and G2+M-phase, mutagenesis, and chromosome damage. However, repair of DNA strand-breaks was the same in monolayers and spheroids. Furthermore, CE is a property of the single cell and does not depend on the proliferative status (cycling or non-cycling) of the cells. We conclude that CE is the result of a physiological modification of the cells occurring during growth in the three-dimensional spheroid matrix and requiring metabolic cooperation and cyclic AMP for its induction.

Animals↗
PubMed1983

Long-term effects of early postnatal nutrition on subsequently body weight gain, emotionally and learning behaviour in male rats.

Male rats have been reared as litters of 2 pups (group A) or 12 pups (group B) during the first 3 weeks of life. Males of group A exhibited higher body weights from day 10 to day 430, reached puberty at earlier age and showed lower emotionality as well as diminished learning capability and decreased memory capacity in adulthood as compared to males of group B. Furthermore, adult males of group A developed an increased ratio of insulin to glucose serum concentration at 90 minutes after glucose administration.

Animals↗
PubMed1982

Intercellular communication, three-dimensional cell contact and radiosensitivity.

When electrically coupled mammalian cells are cultured as spherical clones (spheroids) and exposed to ionizing radiation they are less radiosensitive than monolayers of the same cell line. Investigations into the possible role of coupling (gap junctions) and three-dimensional contact in the expression of this phenomenon revealed 1) a correlation between cell coupling and the activity of adenylate cyclase in monolayers, 2) a sharp drop of cyclase activity in spheroids of coupled cells compared to monolayers, and 3) a decrease of coupling with age ("maturation") of the spheroids. These results suggest profound physiological alterations in communicating cells induced under conditions of tight three-dimensional contact as a possible cause for the reduced radiosensitivity of spheroids.

Adenylyl Cyclases↗
PubMed1981

Pyridostigmine administration in newborn rats prevents permanent mental ill-effects produced by maternal deprivation.

Maternal deprivation from Day 3 to Day 14 of life, i.e., separation of the pups from their mother animals during this developmental period for 16 hours each day, gave rise to highly significantly decreased learning capability and memory capacity in adulthood associated with significantly decreased acetylcholinesterase activity in the brain. These permanent ill-effects of the brain, produced by maternal deprivation of newborn rats, could be prevented by the acetylcholinesterase inhibitor pyridostigmine when administered from Day 1 to Day 14 of life. In view of these findings, teratogenic mental ill-effects, produced by psychosocial and/or nutritional deprivation during brain development, appear to be preventable by correcting abnormal neurotransmitter concentrations during this critical period of brain organization.

Acetylcholinesterase↗
PubMed1981

Effects of neonatal pyridostigmine treatment on sexual maturation and adult behaviour in female rats subjected to maternal deprivation.

The present study deals with the effects on adult behaviour of early postnatal maternal, i.e. psychosocial and/or nutritional deprivation and of altering the brain levels and/or turnover rates of acetylcholine in preweaning deprived rats. The following data were obtained: 1. Female rats separated from their mothers and littermates for 16 hours each day during the first two weeks of life showed a significant delay of puberty onset in comparison with non-separated controls. Furthermore, these animals exhibited significantly reduced emotionality as well as learning capability and memory capacity in adulthood. 2. Administration of the acetylcholinesterase inhibitor pyridostigmine during the first two weeks of life to the deprived females did not compensate the puberty-delaying effect of separation. However, the neonatally pyridostigminized female rats exhibited an increased emotional reactivity in adult life. 3. Female rats deprived from their mothers and treated with pyridostigmine during the neonatal period displayed increased avoidance learning and memory capacity in adulthood as compared to neonatally deprived but untreated animals. It might be concluded from our results that defects of brain differentiation produced by early postnatal deprivation could be prevented, at least in part, by simultaneous administration of pyridostigmine.

Acoustic Stimulation↗
PubMed1980

The effect of simultaneous oral application of ethanol and styrene. [1. Acute and subacute experiments on rats].

Within the lethal dose range, 8.70 mmol/ml ethanol (EtOH, LD50 = 226 mmol/kg) and 6.86 mmol/ml styrene (ST, LD50 = 77.4 mmol/kg) had an additive effect in rats. A four-week pretreatment with 1/10 of the LD50 of the corresponding combination partner did not modify the lethal dose effect of the subsequently administered substance (EtOH or ST). Subchronical treatment with EtOH and ST had an additive effect, too but produced no cumulative effect in relation to lethality. Unlike EtOH, subchronical treatment with ST caused severe symptoms of illness, decrease in body weight and liver lesions. Histological examination at the combined application of EtOH plus ST showed no evidence of qualitatively or intensified effects. Subchronic administration of 1/10 of the LD50-ies of EtOH and ST produced in rats more pronounced histological liver changes than single application of the corresponding LD16-ies. Except for ATP'ase activity, histochemical reactions following EtOH or ST application showed minimal quantitative differences.

Adenosine Triphosphatases↗
PubMed1980

Androgen-dependent sexual dimorphism of the immune system.

An androgen-dependent sexual dimorphism of the immune system was demonstrated in mice. The ration of T/B lymphocytes in the spleen was found to be significantly higher in adult females than in adult males. Furthermore, neonatal androgen administration in females gave rise to a permanent significant decrease of the T/B ratio, while neonatal castration in males resulted in a permanent increase of this ratio.

Animals↗
PubMed1978

Apparent effects of neurotransmitters on sexual differentiation of the brain without mediation of sex hormones.

Male sexual behaviour was found to be permanently decreased in neonatally reserpinized or paragylinized male rats. On the other hand, hypoplasia of sex organs was only observed in reserpinized, but not in pargylinized newborn males. Furthermore, male sexual behavior was found to be permanently increased in neonatally pyridostigminized males which showed even a slight hypoplasia of seminal vesicles in neonatal life. These findings suggest that changes of neurotransmitter concentrations and/or turnover rates apparently induced by psychotrophic drugs can affect sex-specific brain differentiation by direct action without mediation of sex hormones. Hence, neurotransmitters may be regarded as organizers of the brain.

Animals↗