The Feulgen-DNA contents of human leukocytes, sperm, and oral squames were investigated by scanning and integrating microdensitometry, both with and without correction for residual distribution error and glare. Maximally stained sperm had absorbances which at lambdamax exceeded the measuring range of the Vickers M86 microdensitometer; this potential source of error could be avoided either by u...

In this paper, a procedure for correlating electron microscope and light microscope cytochemical studies using immediately adjacent serial thin and thick sections has been described and discussed. This technique, combined with the Feulgen reaction for DNA, has been of particular value in framing and answering both general and specific questions about the nucleus. The results may be summarized a...

Indole ahloids of Vinca species are valued greatly in medical sciences, one reason being for their use as powerful anticancer agents. There are four species of Vinca in Iran: V. rosea, V. major, V. minor and V. herbacea. In previous investigations, we found that these plants have considerable alkaloid similarity (58.8- 75%). Therefore, chromosomic and electrophuretic studies followed after i...

Recent advances in cytochemistry have revealed that two types of nucleic acids play important roles in the cell (for references, 1 and 2). Whereas these two types of nucleic acids, deoxypentose nucleic acid (DNA) and pentose nucleic acid (PNA), have similar ultraviolet absorption properties, they are distinguished from each other by certain color reactions based on their constituent sugars. Amo...

The morphological appearances and some tinctorial properties of the cells of the infectious (viral) papilloma of human skin are described. Pathological alterations of the nuclei of affected cells occur in a definite sequence of stages. In the earliest, and acidophilic Feulgen-negative intranuclear inclusion body is recognizable. Subsequently the inclusion body and nucleus enlarge, there is prog...

Grasshoppers of the species Melanoplus differentialis were injected with tritium-labelled thymidine. At intervals thereafter autoradiographic stripping film was applied over Feulgen squashes and sections. In this species during early prophase of meiosis the sex chromosome forms a heterochromatic block large enough to be resolved in tritium autoradiographs. A study of the squash preparations rev...