Search PubMed⌕ Search

Biomedical subjects

E Zeuthen

Publications and source records attributed to E Zeuthen.

At least 19 recordsLinked to original sources

Synergistic effects of p-fluorophenylalanine and supra-optimal temperatures on cell division in Tetrahymena pyriformis.

The combined effects of sub-optimal (20 degrees) or supra-optimal (31 degrees C and 34 degrees C) temperatures and the amino acid analogue p-fluorophenylalanine on preparations for cell division in Tetrahymena pyriformis were analysed. A supra-optimal temperature of 31 degrees produced a marked exaggeration of the division-delaying capacity of the analogue. The analogue also sensitises cells when combined with the normal heat shock temperature of 34 degrees, which indicates that division proteins continue to be synthesized at this temperature but cannot be effectively utilized by the cell. These results support the model that preparations involve interactions between and formation of assemblies of proteins on a strict time schedule shortly before division.

Animals↗

Analysis of the time of utilization of proteins for the initiation and completion of division in synchronized Tetrahymena pyriformis.

We exposed division-synchronized Tetrahymena pyriformis to pulse treatments with the structural amino acid analogue p-fluorophenylalanine. We related the timing of the treatments to the delays in onset or completion of division, or both. The results enable us to distinguish between early and late phases in cell division in which the cells bring into action proteins which contribute to initiate and complete division, respectively. Normally, these events are separated by 25-30 min.

Animals↗

Prevalence of Klinefelter's syndrome (47,XXY) in a general male population.

In a representative sample of 3,840 males examined for military service chromosome examination was made in those with testes equal to or less than 12 ml and those with a stature equal to or greater than 181 cm, as well as in males not recruited because of physical or mental disability. Testes equal to or less than 12 ml were found in 59 patients (1.45%). Three of these males had a 47,XXY karyotype (5.1%), the prevalence among the total sample of 3,840 being 0.78 per 1,000. Hypogonadal signs, except for gynaecomastia, which was only present in one patient, were found in the saem proportion as in 47,XXY males ascertained in institutions and clinics. The results of EEG investigations were alos similar to those found in psychiatric institutions. The intelligence level was comparatively low; none had an IQ above 100. The personality traits corresponded to those found in institutionalized Klinefelter males.

Adult↗

Linear increase in glycolytic activity through the cell cycle of schizosaccharomyces pombe.

The glycolytic activity of 3 different synchronous system in S. pombe was studied. Synchronous cultures were produced by a selection procedure, by cyclic heat treatment, or by cloning cells from an exponentially multiplying culture. In all experiments a complex medium with 3% glucose was used. The glycolytic activity was recorded with a gasometric method, the gradient diver. A single cell in exponential growth or a small number of synchronized cells were placed in ampulla divers in which the cells progressed undistrubed through a number of cycles. An ampulla diver is in principle a narrow pipette by which a single or a few cells are removed from the mother culture. It serves next as an axenic growth chamber and at the same time as a gasometer. The divers were placed in linear saline density gradients and the gaseous exchanges taking place in the divers resulted in migration of the divers. The migration rate is a measure of the glycolytic activity of the cells. Our results show that the glycolytic activity increases in a linear fashion between sucessive divisions. The rate of increase doubles at each division. This true in all 3 synchronous systems, and we take this as an indication that the cell cycles of heat-synchronized cells do not deviate seriously from the normal.

Ascomycota↗

A psychiatric-psychological study of XYY males found in a general male population.

The psychological test results of five XYY males from in a population study showed an intellectual level within the normal range but with a mean full scale IQ and educational level lower than expected. The cognitive as well as emotional function was characterized by immaturity, manifested in passivity, unreflectiveness and emotional liability, in three resulting in uncontrolled aggressive outbursts. Conflict material also appeared immaturely resolved, centering around unfulfilled needs of contact and insecure masculine identification. The defense mechanisms used were generally rather weak, but only in one subject did the anxiety level seem to be excessively low. All five males differed to a certain extent from their siblings; three of them were hyperactive, restless, hot-tempered and impulsive at school and four of them had difficulties at school. Three learned a trade, but only one stayed in his trade, and one was applying for disablement pension on account of personality deviation. Two of the five had a criminal record. It is concluded that the presence and degree of the above-mentioned characteristics of XYY males varied. It is evident that environmental factors play as great a role for the development of personality and behaviour in males with karyotype 47, XYY as in males with a normal chromosome constitution.

Adult↗