Methods are disclosed for the characterization of the stage of development or pathology of a tissue sample, and for identifying pluripotent metakaryotic stem cells, comprising detecting fluorescence of cells and syncytia in fixed samples treated with a non-fluorescent Schiff’s base reagent in the absence of extraneous or exogenously added fluorescent dyes. The test port assembly includes a first end section, a second end section, and a rotating section adapted for rotation between the first and second end sections. The connecting component includes a sleeve part for engaging threadedly the low-noise block converter and the filter, and a core extending through the sleeve part and interconnecting electrically the output circuit and the filtering circuit. A method of using the tool is also disclosed. 01-10 parts by mass of an inorganic layer material to 100 parts by mass of said main constituent material, in addition to said main constituent material and said organic binder.