Re-analysis of radiation-induced specific locus mutations in the mouse.

A re-analysis of published data on mouse mutation rates induced by X and gamma rays suggests that the kinetics of induction can be analysed by fitting the data to a parabolic curve. We interpret this to mean that a substantial proportion of the induced mutations results from gross chromosomal changes such as deletions, some of which are one-track and some of which are two-track. This analysis is based on the assumption that the shape of the dose curve, which in the female is concave upward, reflects the manner in which the mutations are induced rather than representing a one-track (linear) curve whose shape has been modified by differential repair.     

A new method for measuring guanidine in uremia

Riassunto Si descrive un metodo per la determinazione della guanidine nei liquidi biologici e si rileva che essa aumenta nel siero uremico fino a 30 volte la norma (valore medio normale: 1.41±0.49 g/100 ml) e che nei cani uremici la concentrazione muscolare è di quasi 3 volte superiore a quella plasmatica. La eliminazione urinaria non è diversa fra normali ed uremici: 382±221 e 459±229 g/24 h, rispettivamente.

---

---

Aknowledgments. This investigation was supported by Public Health Service, Research Contract No. PH-43-68-1466.     

Calcium sensitivity of succinate and pyruvate dehydrogenases in the denervated amphibian skeletal muscle

Zusammenfassung Es wird nachgewiesen, dass die Aktivität von Succinat Dehydrogenase und von Pyruvat Dehydrogenase in Extrakten normaler und denervierter Muskulatur durch Ca⁺⁺ im pH-Bereich von 5,8 bis 7,8 in verschiedenem Ausmass erhöht bzw. erniedrigt wird.     

Approach to a quantitative differentiation between the respiratory effects evoked from the lung stretch and the lung deflation receptors during thoracic compression

Zusammenfassung Die beiden Annahmen, dass sich bei Thoraxkompression die Verminderung der Impulssequenz der Lungendehnungsrezeptoren analog zum Lungenentdehnungsreflex auswirke, und dass sich dessen inspiratorische Atmungseffekte zu jenen des Lungenkollapsreflexes addieren, erscheinen gerechtfertigt. Diese Annahmen ermöglichen eine quantitative Differenzierung zwischen dem respiratorischen Einfluss der Lungendehnungs-und Lungenkollapsrezeptoren bei Thoraxkompression. Damit können die auf die Erregung der Lungenkollapsrezeptoren zu beziehenden Atmungsveränderungen (f,I/E) erstmals isoliert und quantitativ dargestellt werden.

---

---

Presented at the 2nd Meeting of the Swiss Physiological Society, Zürich, 8 November 1969.