PubMed Health⌕ Search

Biomedical subjects

D Bloch

Publications and source records attributed to D Bloch.

12 recordsLinked to original sources
PubMed1978

Flow-cytometric analysis of chicken red blood cells.

Flow-cytometric analysis of acriflavin-Feulgen stained chicken erythrocytes shows a complex distribution of amounts of deoxyribonucleic acid fluorescence, the profile consisting of a main peak and a right hand shoulder. This bimodal distribution, an artifact characteristically seen on analysis of flattened cells using orthogonal flow systems, results from fluorescence emission in preferred directions stemming from the combined effects of refractility and orientation of the cells. The shoulder disappears on analysis of lysed erythrocyte ghosts, also on analysis of cells in a medium whose refractive index approximates that the cells. An orientation effect for matrue erythrocytes was indicated by reanalysis of fractions after sorting on the basis of high and low fluorescence or scatter signals. Both fractions gave the original range of values on reanalysis, although some changes in shape of the profile and in the peak positions for the sorted cells were seen. Sodium dodecyl sulfate treatment of stained cells "loosened" the cells' structure, yielding lowered scatter values, and fluorescence values approaching those of the shoulder. The average fluorescence emission of the erythrocytes was lower than that of reticulocytes and lymphocytes. The values of the latter correspond closely, although coincidently, to that the erythrocyte shoulder values. Dual parameter analysis of forward light scatter, and fluorescence, which was detected at 90 degrees to the laser beam, showed the low fluorescence to be accompanied by low scatter signal, and the high fluorescence among the cells with the high scatter signal. The lowered forward scatter signal is due to a wider scattering of light from cells oriented edge-on to the detector, and loss of signal beyond the acceptance angle of the detector. These results suggest that the preferred directions for fluorescence are in the plane of the cells, and the values are dependent on the cells' orientation in the stream. These interpretations were supported by the results of analysis of partially oriented cells. The approaches used and conclusions arrived at are similar to those of Gledhill et al (16), Van Dilla et al (37), in their analysis of fluorescence of flat sperm cells although the affects in the case of the erythrocytes are less extreme.

Animals↗
PubMedDate not supplied

The pathology of head and neck tumors: salivary glands, part 3.

The term adenoma is applied to a rather wide variety of histopathologic entities in the salivary glands. These include tumors derived from the ductal epithelium and/or from myoepithelial cells and other salivary-gland elements, such as the sebaceous glands. Within the categories of mixed tumor (pleomorphic adenoma), monomorphic adenoma, clear-cell tumor, and sebaceous lesions, there are also several subtypes, each of which lends further credence to the germinative potential of the salivary tissues. Presented in this report is a clinicopathologic and histogenetic analysis of these lesions. Specifically discussed are mixed tumor, monomorphic adenoma, carcinoma ex-pleomorphic adenoma, clear-cell tumor, sebaceous lymphadenoma, and sebaceous carcinoma.

Adenoma↗