Experientia

A male mouse with one translocation involving theY-chromosome has been observed in the F1 offspring of a male mouse given 300 R of X-irradiation. 6 types of spermatocytes were recorded. Our observations appear to confirm that the acrocentricX of the mouse associates end-to-end with theY at its centromeric end.

The effects of exchange-transfusion with a proprietary gelatin-based plasma volume expander, Haemaccel, have been investigated in conscious, chronically-catheterized rats. No adverse changes in basic cardiovascular or respiratory functions occurred during the procedure although an increase in intravascular fluid sodium but not potassium concentration was observed.

Ecdysteroid titers were determined in the hemolymph of adult freshwater prawn,Macrobrachium rosenbergii, during various stages of the molt cycle, using radioimmunoassay. A comparison was made between hormone levels in males which undergo normal molt and dominant males of the population which periodically commit cheliped autotomy. The latter is a recently discovered phenomenon whereby a male voluntarily sheds off both its long claws at molt, once the ratio between body length and combined claw length reaches a ceiling level of about 1∶3. Shortly before an autotomizing molt, hormone levels were about three times higher than on the eve of a normal molt.

No qualitative differences have been found between the electrophoretic protein patterns observed in normal and in aneuploid embryos (♀ 3n × ♂ 2n). The overall amount of extractable protein increases, however, less rapidly in aneuploid than in normal embryos.

The gracilis muscle was excised from cold-acclimated rats, placed in vitro, and simultaneously perfused via its artery by high pO2 medium and superfused by low pO2 medium. With a doubling of the perfusion rate (from 50 to 100 μl/min) phosphocreatine and ATP increased by 39% and 44%, respectively.

The thermo-elastic properties of nerve have been studied by measurements of the change in length caused by changes in temperature. The thermal coefficient (per °C) of linear expansion, always positive in sign, is of the order of 10−4 for intact nerve and 10−5 for dissected nerve.