Abstract: An apparatus for limiting pipette head travel with respect to a ground surface, and for limiting insertion of a pipette into a tube, has a top surface including at least one aperture. Each aperture selectively and concurrently accepts a corresponding pipette head of a pipette device therethrough. A bottom surface extends substantially parallel to the top surface and selectively contacts the ground surface. A plurality of side surfaces extends transversely between the top and bottom surfaces. The side surfaces each have a predetermined height correlated with a desired minimum approach distance of each pipette head toward the ground surface. The top, bottom, and side surfaces collectively enclose and define a spacer volume, at least partially through which each pipette corresponding to a pipette head extends. Methods of limiting pipette head travel with respect to a ground surface, and of limiting insertion of a pipette into a tube, are also provided.

Abstract: A method of detecting chromosomal damage in a subject is described that includes the steps of stimulating proliferation of the lymphocytes of a blood sample from a subject by contacting them with a labeled mitogen; growing the stimulated lymphocytes in cell culture; contacting the lymphocytes with a mitotic arrest agent to arrest the lymphocytes as binucleate lymphocytes; staining the lymphocytes with a DNA binding dye; detecting labeled mitogen to define the cytoplasm boundary of binucleated lymphocytes; counting the micronuclei in one or more binucleated lymphocytes to obtain an observed micronuclei value; and determining the level of chromosomal damage in the subject by comparing the observed micronuclei value with a control micronuclei value. The method can be used to conduct biological dosimetry on subjects who are suspected of having been exposed to radiation.

Abstract: An apparatus for limiting pipette head travel with respect to a ground surface, and for limiting insertion of a pipette into a tube, has a top surface including at least one aperture. Each aperture selectively and concurrently accepts a corresponding pipette head of a pipette device therethrough. A bottom surface extends substantially parallel to the top surface and selectively contacts the ground surface. A plurality of side surfaces extends transversely between the top and bottom surfaces. The side surfaces each have a predetermined height correlated with a desired minimum approach distance of each pipette head toward the ground surface. The top, bottom, and side surfaces collectively enclose and define a spacer volume, at least partially through which each pipette corresponding to a pipette head extends. Methods of limiting pipette head travel with respect to a ground surface, and of limiting insertion of a pipette into a tube, are also provided.