Relationship of ploidy and chromatin condensation in the rat liver, moreover a comparison of the nuclear texture in sections and touch preparations

DNA content, chromatin supraorganization, nuclear glycoproteins and RNA amounts in hepatocytes of mice expressing insulin-dependent diabetes

Chromatin supraorganization and extensibility and nuclear glycoprotein content have been reported to change in hepatocytes from mice during development and aging, as well as under starvation and refeeding conditions. In non-obese diabetic (NOD) mice, the expression of insulin-dependent diabetes may be accompanied by metabolic changes in the liver. These changes are likely to be similar to those involved in the aging processes of non-diabetic animals. Therefore, we hypothesized that the chromatin organization, as well as the physical properties and compositions of hepatocyte nuclei would also be affected in NOD mice in the same way as those in aged non-diabetic mice. Nuclear image parameters were evaluated by image analysis of Feulgen-stained preparations. Chromatin extensibility in response to gravity was observed with polarized light after lysis and toluidine blue staining. The Con-A response of nuclear glycoproteins was evaluated with scanning microspectrophotometry. These characteristics were assessed using hepatocyte imprints from female NOD mice after a 28-day period of diabetes expression. Observations and measurements were made in comparison to healthy BALB/c mice. Total RNA amounts were determined for livers of NOD and BALB/c mice. Enhanced polyploidy levels, a decrease in chromatin higher-order packing states, an increased frequency of extended chromatin fiber formation, and deeper Con-A-responsive chromatin areas were observed in the hepatocytes of the NOD mice expressing insulin-dependent diabetes. Reduced amounts of total RNA were also found in the livers of these mice. Our findings for NOD mice expressing insulin-dependent diabetes are consistent with previously reported data for old-aged mice of the inbred strain A/Uni and may reflect changes in transcriptional activities associated with the stressful physiological demands on the liver during the expression of diabetes.

Size and number of binucleate and mononucleate superior cervical ganglion neurons in young capybaras

The total number of neurons in the superior cervical ganglion (SCG) of adult capybaras is known from a previous study, where a marked occurrence of binucleate neurons (13%) was also noted. Here, distribution, number and fate of binucleate neurons were examined in younger, developing capybaras, aged 3 months. The mean neuronal cross-sectional area was 575.2 microm2 for mononucleate neurons and 806.8 microm2 in binucleate neurons. Frequency of binucleate neurons was about 36%. The mean ganglion volume was about 190 mm3 in young capybaras and the mean neuronal density was about 9,517 neurons/mm3. The total number of neurons per ganglion was about 1.81 mill. Neuronal cell bodies constituted 22.5% of the ganglion volume and the average neuronal volume was 23,600 microm3. By comparing the present data with those previously published the conclusion is drawn that the maturation period was characterized by the following points: a 26% remarkable decrease in neuronal density which was significant (P < 0.05) and a significant 16% (P < 0.05) decrease in the total number of SCG neurons accompanied by a 23% decrease in the total number of SCG binucleate neurons.

Prognostic significance of DNA cytometry in cutaneous malignant lymphomas

The current classification of cutaneous malignant lymphomas (ML) into low-grade and high-grade lymphomas was found to be of limited reproducibility and permitted only a rough prediction about outcome. With this in mind, the relationship between nuclear DNA content and both prognosis and histologic grading according to the Kiel classification was evaluated on Feulgen-stained imprint specimens. In all, 49 cases of malignant non-Hodgkin's lymphoma, primary of the skin or with an involvement of the skin as one of the first symptoms, were studied using a computerized high-resolution image analysis system. The 2c deviation index (2cDI), which reflects the variation of the nuclear DNA values around the normal diploid peak, was found to be the best prognostically relevant criterion. Using the 2cDI, a significant discrimination (P less than 0.001 in the U test) between low-grade and high-grade ML was achieved. The prognostic benefit of the 2cDI was well documented by a significant inverse correlation between the 2cDI and the period of time until the patients progressed at least into one higher stage or died of lymphoma (r equals -0.63, P less than 0.05). In addition, the 2cDI enabled prognosis of the course of disease. In the group with low 2cDI values (2cDI, less than 0.5), no progression of the disease was observed after 1 year. In the groups presenting with a 2cDI between 0.5 and 1.0 and higher than 1.0, a progression was found in 57% and 64% of the cases studied, respectively. In conclusion, these measurements indicate that the determination of DNA distribution patterns in imprint specimens allows a precise and objective prognostic evaluation of cutaneous ML.

Differentiation between lymphomas and pseudolymphomas of the skin by computerized DNA-image cytometry

The histologic and immunohistologic differential diagnosis between pseudolymphomas (PL) and malignant lymphomas (ML) of the skin can be difficult. Since DNA cytometry has been found to be of both diagnostic and prognostic value in various neoplasms, its ability to discriminate between ML and PL in Feulgen-stained imprints of 17 PL and 49 ML skin biopsies was examined by high-resolution image analysis. The reliability of the following algorithms of DNA distribution was evaluated: 1) 2cDI (2c-deviation index), which reflects the variation of the nuclear DNA values around the diploid DNA peak; 2) percentage of cells having a DNA value greater than or equal to 5c (5cER; 5c-exceeding rate); 3) percentage of cells presenting with a DNA value greater than or equal to 4c (4cER). A 2cDI of 0.1 was found to be the most reliable marker for the differentiation between PL and ML. On the basis of this feature, 16 of 17 cases of PL and 46 of 49 cases of ML were correctly classified. The sensitivity, specificity, and efficiency of this feature were 94%. A 5cER greater than or equal to 1% had a specificity of 100%, but the sensitivity was only 43%. For the 4cER, a sensitivity of 61% and a specificity of 94% were found. In conclusion, the calculation of the 2cDI and the 5cER based on high-resolution image analysis provided additional helpful diagnostic features, and therefore should be included as a diagnostic tool. If the 5cER is at least 1%, the diagnosis of a ML can be confirmed with a specificity of 100%.

Measurements of the DNA amount in mono- and binucleate cells in the celiac superior mesenteric ganglion of the guinea pig

The relative proportion, ultrastructure and DNA-content of the binucleate cells in the celiac superior mesenteric ganglion of the guinea pig was studied using light and electron microscopy as well as computerized image analysis of Feulgen stained cells. The number of mono - versus binucleate cells was found to vary with stage of development with about 40% of the cells being binucleate in adult animals and 50% in late prenatal stage. No difference in ultrastructure was observed between the nuclei of the two cell types. The binucleate cells contain twice the amount of DNA found in the mononucleate cells.

A double staining method for measuring DNA content of specific cell populations utilizing computerized microscopy

A method for identifying specific cell populations with the computerized microscope is described. This method utilizes double staining techniques using immunofluorescent antibodies and the Feulgen technique. It was applied to measure the area and DNA content of the nuclei of beta-cells in patients with Persistent Neonatal Hypoglycemia with Hyperinsulinism (PNHH). A significant increase in the area and DNA content was found in nuclei of patients compared to a control group. This method may be applied to sample cells from other tissues as well.

Microfluorometric investigations of chromatin structure. I. Evaluation of nine DNA-specific fluorochromes as probes of chromatin organization

The ability of the highly condensed chromatin of small thymocyte nuclei and the more loosely organized chromatin of hepatocyte nuclei to interact with nine DNA-specific fluorochromes was assessed by microfluorometry. Although the results obtained with five of the fluorochromes - mithramycin, 7-aminoactinomycin D, Hoechst 33258, DAPI, and propidium iodide - were found to be virtually unaffected by differences in the degree of condensation of the chromatin, the values obtained with the remaining fluorochromes - proflavine, quinacrine mustard, berberine sulfate, and pyronin Y - appeared to be affected significantly by organizational differences of the chromatin. All of the latter "structural probes," except quinacrine mustard, produced fluorescence values which were higher in the 2c nuclei of hepatocytes than in the nuclei of small thymocytes. Quinacrine mustard yielded higher values in thymocyte nuclei; and in the hepatocyte polyploid series (2, 4, and 8c), it did not produce the expected multiples of the 2c value. Pretreatment of the two types of nuclei with RNase affected their total fluorescence in unpredictable ways. While RNase extraction lessened the differences between thymocyte and 2c hepatocyte nuclei stained with propidium iodide, Hoechst 33258, proflavine, and berberine sulfate, it increased the differences between nuclei stained with mithramycin, quinacrine mustard, pyronin Y, and 7-aminoactinomycin D. The ability of RNA-depleted chromatin to interact with various types of fluorochromes might be a useful parameter in subsequent studies of chromatin organization.