Influence of potassium and calcium ions on the phosphatidylinositol and phosphatidylcholine metabolism in rat fibroblasts after growth stimulation by calf serum

In secondary cultures of embryonic rat fibroblasts which were arrested in G1 (G0) by serum depletion and subsequently triggered into the cell cycle by readdition of growth factors isolated from fetal calf serum the influence of the potassium and calcium concentrations in the medium on phosphatidylinositol and phosphatidylcholine metabolism was investigated. The incorporation of inorganic [32P]phosphate into phosphatidylinositol is dependent on the potassium content of the culture medium. The specific activity of 32P in phosphatidylinositol is increased at K+ concentrations between 0.1 and 1 mM. Also calcium (between 0.01 and 2 mM) slightly stimulates phosphatidylinositol metabolism. Also the incorporation of myo-[3H]inositol is increased at potassium concentrations between 0.2 and 1 mM, whereas calcium is slightly inhibitory. The labelling of phosphatidylcholine with either [32P]phosphate or [3H]choline is not dependent on the potassium and calcium concentrations of the culture medium. Moreover, the phospholipid metabolism of permanently growing epithelioid and fibroblastoid cells lines, which were investigated, is considerably less dependent on the K+ and Ca2+ ions.

Lesions in chickens with spontaneous or experimental infectious hepato-myelopoietic disease (inclusion body hepatitis) in Germany

A group of 83 two-to-eighteen-week-old chickens with acute infectious hepato-myelopoietic disease (a German form of inclusion-body-hepatitis) were observed to have the following histologic lesions: panmyelophthisis, small foci of liver necrosis, often with intranuclear inclusion bodies in hepatocytes (15 to 20% of chickens), involution-like atrophy of the bursa of Fabricius and thymus, loss of lymphatic tissue in spleen and cecal tonsils, and nonpurulent myocarditis. In 18 survivors 6 to 8 weeks after clinical signs of disease, nonpurulent myocarditis but normal lymphatic organs and bone marrow were present. A group of 75 chickens were infected after hatching with the field isolant "1942." Between the 3rd and 9th weeks postinoculation the same histologic changes-though mostly milder-were demonstrated. This syndrome differs somewhat from the syndrome described as inclusion body hepatitis in America and Europe.

Short-term habituation of the infant auditory evoked response

Short-term habituation of the vertex auditory evoked response was studied in six infants (age 10 to 14 weeks). The infants were presented trains of four synthetic speech stimuli. The average amplitude of the evoked responses was largest to the first member of the stimulus train and then decreased rapidly. The average amplitudes to the second, third, and fourth stimuli in the train were 36, 41, and 22% of the first stimulus amplitude, respectively. The results suggest that the auditory evoked response of awake infants satisfies several of the criteria for short-term habituation.

The Energy of Substituted Ethanes. Asymmetry Orbitals

The leading terms in the energy of a general substituted ethane are derived in explicit form as a function of the torsional angle θ , the substituent electronegativities, and their mutual overlaps. The energy is found to be the sum of all four overlaps between pairs of asymmetry orbitals, and satisfies the requisite symmetry properties.

[Elimination of XX cells in the tests of heterosexual bovine twins with XX-XY chimerism]

In five heterosexual male bovine twins and three freemartins, all not older than three months, XX/XY chimerism in the blood and gonads has been found. One heterosexual male bovine triplet showed at the age of 18 or 22 months XX/XY chimerism in the blood but not in the testes. In another male co-twin of a freemartin, XX/XY chimerism has been detected in the blood and the testes (at biopsy) at the age of two months. In the same animal, the blood chimerism was still present at the age of 18 months, whereas the chimerism of the testes had vanished at that time. Therefore, it can be concluded that, in the course of time, the XX cells of the testes have been eliminated. This elimination, which possibly occurs in embryonic life, partially explains why male co-twins of freemartins do not have malformations of the genital organs and are fertile. Possibly, the XY cells of the testes have an eliminating influence against neighbouring cells with an XX karyotype. The eliminating effect could be directed at the two active X chromosomes of these germ cells. The hypothesis would also account for the observation that blood lymphocytes with an XX karyotype, which have, according to the Lyon hypothesis, only one active X chromosome, are not eliminated with time.