Electron microscopic morphometric analysis of human T and B peripheral blood lymphocytes

Ethanol affects calmodulin and the calmodulin-binding proteins neuronal nitric oxide synthase and alphaII-spectrin (alpha-fodrin) in the nucleus of growing and differentiated rat astrocytes in primary culture

The distribution of calmodulin (CaM) and the CaM-binding proteins neuronal nitric oxide synthase (nNOS) and alphaII-spectrin (alpha-fodrin) in the nucleus of growing and differentiated astrocytes was analysed using immunogold electronmicroscopy. We also analysed the effect of moderate ethanol exposure on these proteins. For this, female Wistar rat were fed with an alcoholic liquid diet and exposed to males after several weeks. Pregnant rats were fed with this diet and, after birth, the foetuses brains were used to establish primary cultures of astrocytes. Astrocytes from control and ethanol-exposed rats foetuses were cultured in the absence or presence of ethanol (30 mM) for 7 days (growing cells) and 21 days (differentiated astrocytes). Our results indicate that all the proteins studied appeared mainly on the condensed chromatin of both control- and alcohol-exposed cells and that there are significant variations in the amount of these proteins between quiescent and dividing astrocytes. Altogether, we have not found a co-localisation between CaM and the CaM-binding proteins.

Analysis of chromatin pattern in blood lymphocytes of healthy donors and in lymphoid cells of patients with chronic lymphocytic leukaemia

The optical Fourier transformation was used to analyse the chromatin/interchromatin pattern of lymphocytes of healthy subjects and lymphoid cells of patients with chronic lymphocytic leukaemia (CLL, type B, stage O). Peripheral blood smears were prepared routinely, fixed, and stained by the Feulgen method, and the photographic images of the nuclei were quantitatively analysed. From the radial distribution of light intensity of diffractograms, several Feulgen chromatin (F-chromatin/interchromatin) descriptors were evaluated. Four showed the strongest discriminant power and these descriptors discriminated well between lymphocytes of healthy donors and lymphoid cells of CLL patients, although F-chromatin/interchromatin components of the same sizes were found in lymphocytes and lymphoid cells.

Non-Hodgkin's lymphoma classification: ultrastructural morphometric studies for the quantification of nuclear compartments in situ

The condensed chromatin distribution in the nuclei of lymphocytes in non-Hodgkin's lymphoma (NHL) is a key element, along with nuclear size and shape, in the classification of this disease for therapeutic and prognostic purposes. This report describes the ultrastructural comparative quantification of the condensed chromatin and the interchromatinic (nuclear matrix or euchromatin) region in the nuclei of mitogen-stimulated human peripheral T lymphocytes and mouse spleen B lymphocytes, human germinal center lymphocytes, and lymphocytes in ten cases of NHL of a variety of subtypes. The sequential morphologic nuclear changes induced in lymphocytes by mitogens are reflected in human germinal center lymphocyte populations. The common features include the changes in the distribution and volume of condensed chromatin aggregates, as well as the fact that the major increments in nuclear volume during lymphocyte transformation result from increases in the volume of the interchromatinic region. In all subtypes of NHL analyzed morphometrically, subpopulations of lymphocytes were identified in which mean nuclear, condensed chromatin, and interchromatinic volumes were more or less equivalent to those of normal lymphocyte subsets in germinal centers in reactive hyperplasia. However, in NHL the abnormal cytologic characteristics of the nucleus result, at least in part, from a complex interplay of condensed chromatin distribution and amount, and the size of the interchromatinic region. Further complexity is introduced by the fact that in NHL these two nuclear compartments can independently be normal, increased, or reduced in size. Morphometric quantification of lymphocytes in NHL indicates that the interchromatinic (matrix) region of the nucleus is the key element in establishing the nuclear volume of neoplastic lymphocytes. The structural and functional, ribonucleoprotein interchromatinic region of the nucleus was visualized in normal and neoplastic lymphocytes by regressive uranyl-EDTA staining. Quantitative morphometric analysis indicates that the cytologic appearance of neoplastic lymphocytes, even within subtypes of NHL, is heterogeneous and that condensed chromatin quantity and distribution may be more critical than nuclear size in distinguishing between certain subtypes of NHL. Improvements in the classification of NHL will occur only with understanding of the alterations in the biologic mechanisms controlling gross nuclear organization and the morphologic events of the various differentiation pathways available to antigen-stimulated lymphocytes.

Effects of urease-induced hyperammonemia in mouse liver. Ultrastructural, stereologic and biochemical study

Intraperitoneal injections of urease induced a marked and sustained hyperammonemia in mice. Ultrastructural and stereologic analysis of hepatocytes from urease-treated mice showed striking changes in the mitochondria, rough and smooth endoplasmic reticulum and lysosomes. Thus, mitochondria became larger and rounder, and contained a less electron-dense matrix although their volume density remained similar to that of control cells. In addition, increases in the smooth and rough reticulum and the lysosomal compartment, were observed. Biochemical analysis of the livers from urease-treated mice revealed a significant increase in the intracellular content of water and lipids. Although the mechanism by which ammonia induces these changes remains unclear, the possible relationship between these findings and those described in the liver of humans and experimental animals in conditions of sustained hyperammonemia is discussed.

Stereological analysis of the ultrastructure in isolated human T and non-T lymphoid cells. I. Description of method and data on normal blood lymphocytes

Stereological techniques were applied to isolated and purified normal human T and non-T lymphocytes from the peripheral blood, allowing a quantitative characterization of the average cell and its subcellular components in each population at the ultrastructural level. From electron micrographs taken at two levels of magnification and subjected to point counting procedures and measurements on a Kontron Videoplan analyser, absolute and relative data comprising volumes, surfaces and ratios were obtained. The stereological model proved efficient in establishing important differences between the two lymphocyte subsets regarding features generated from the whole cell as well as from the nuclear and cytoplasmic compartments. Thus the average T cell compared to the non-T cell possessed the following qualities: a smaller cell volume and cell surface area due to a smaller cytoplasmic volume and surface area; a lower nuclear euchromatin-heterochromatin volume ratio indicating a greater amount of heterochromatin in the nucleus; a smaller volume and surface area of rough ER, and (to a less extent) a smaller amount of Golgi apparatus, dense bodies and residual cytoplasm. The rare occurrence of parallel tubular arrays were seen in the non-T fraction only, and dense bodies were more often clustered in T cells. The differences are discussed in immunological and functional terms.