title: A versatile microfiltration device.
abstract: A versatile vacuum microfiltration device was designed for separation of small volumes of liquid from samples of cells or subcellular organelles through membrane filters. It is especially useful for separation of small samples from radioactive tracer when low blank values are mandatory for the performance of the measurement. In the present communication the microfiltration device was used for the separation of organelles from incubation medium labeled with 45Ca2+ for measurement of uptake of 45Ca2+ by small samples of liver or pancreatic islet mitochondria or of pancreatic islet secretory granules. Measurement of 45Ca2+ uptake was possible in samples containing less than 1 microgram of protein even if the sample was incubated with only 10,000 cpm of 45CaCl2. Blank values ranged only between 2.6 and 4.7% of the test values. The device should be useful for a variety of applications in many research areas where sample volumes are small.
mesh_terms: D000818:Animals; D002118:Calcium / Q000302:isolation & purification / Q000378:metabolism; D003470:Culture Media / Q000032:analysis; D066298:In Vitro Techniques; D007515:Islets of Langerhans / Q000032:analysis; D051379:Mice; D008928:Mitochondria / Q000032:analysis; D008930:Mitochondria, Liver / Q000032:analysis; D013347:Subcellular Fractions / Q000032:analysis*; D014462:Ultrafiltration / Q000295:instrumentation*; D014618:Vacuum
chemical_list: D003470:Culture Media; D002118:Calcium