Survival of mouse type B spermatogonia for the study of the biological effectiveness of 1 MeV, 2.3 MeV and 5.6 MeV fast neutrons.

The most radiation-sensitive cells in the testis are B and intermediate spermatogonia. We have used a histological scoring technique to compare three neutron beams of different mean energies (1 MeV at the ECN, Petten, 2.3 MeV at the Gray Laboratory, Northwood, and 5.

Reversible harmless interruption of testicular blood supply in the ram.

An effective method of interrupting testicular blood flow temporarily and repeatedly in the ram has been developed. Blockade of flow has been achieved mechanically by an inflatable occluder placed around the testicular artery at the level of the spermatic cord. The effect of the blockade on total testicular blood supply was investigated using Doppler flowmetry and a percutaneous Xenon-133 injection method.

Cell-cell interaction between rat Sertoli cells and mouse germ cells in vitro.

An antiserum against rat germ cell membranes was prepared, and after absorption with protein extracts of rat liver and kidney and mouse testis, this antiserum reacted only with rat germ cell membranes and juxtanuclear vesicles in rat Sertoli cells. Germ cell-free rat Sertoli cell monolayers were cultured in vitro. Freshly isolated mouse germ cells adhered to these monolayers within 1 h.

Strain differences in the response of mouse testicular stem cells to fractionated radiation.

The survival of spermatogonial stem cells in CBA and C3H mice after single and split-dose (24-hr interval) irradiation with fission neutrons and gamma rays was compared. The first doses of the fractionated regimes were either 150 rad (neutrons) or 600 rad (gamma). For both strains the neutron survival curves were exponential.

Growth and differentiation of spermatogenetic colonies in the mouse testis after irradiation with fission neutrons.

The longitudinal outgrowth of spermatogenetic colonies arising from stem cells that survived neutron doses of 150, 300, and 350 rad was studied up to 30 weeks in histological sections of CBA mouse testes. Two methods were used: (1) the repopulation index (RI) as a measure of the length of total colonies per testis and (2) measurement of the individual length of all colonies in serially sectioned testes 4 and 15 weeks after 300 rad and 15 weeks after 350 rad. The mean initial growth of the colonies is linear up to 8, 15, and 20 weeks after 150, 300, and 350 rad, respectively.