Bahr Gf

INTRODUCTION TO QUANTITATIVE CYTOCHEMISTRY

Inevitably, reading is one of the requirements to be undergone. To improve the performance and quality, someone needs to have something new every day. It will suggest you to have more inspirations, then. However, the needs of inspirations will make you searching for some sources. Even from the other people experience, internet, and many books. Books and internet are the recommended media to help you improving your quality and performance.

A Photometric Procedure for Weight Determination of Submicroscopic Particles Quantitative Electron Microscopy

A photometric procedure for rapid determination of weight of isolated particles down to a size of 200 A is described. Under normal conditions of electron microscopy, weights of down to 10−18 g can be determined with an inaccuracy of less than 10%. By lowering the accuracy or using more elaborate measures (such as very low accelerating voltage) one to two orders of magnitude for the lower weight limit can be gained. The method can now be applied to population studies of biologic particles, especially those of inhomogeneous and odd‐shaped entities. Individual losses of matter through the action of enzymes and the uptake of specific stains can be measured quantitatively. The method extends the possibilities of individual mass‐weight determination to the biologically important region of submicroscopic particles.

Scanning Electron Microscopic Observations of Surface Structure of Isolated Human Chromosomes

Isolated human chromosomes dried by the critical-point method have been assumed to retain their original three-dimensional shape when viewed under a transmission electron microscope. Our scanning electron microscopic study confirms this interpretation and reveals an appearance like that of a skein of yarn. The existence of fiber bridges between chromatid pairs and among chromosomes is demonstrated.

Comparison of G-, Q-, and EM-banding patterns exhibited by the chromosome complement of the Indian muntjac, Muntiacus muntjak, with reference to nuclear DNA content and chromatin ultrastructure

When the chromosomes of the Indian muntjac, Muntiacus muntjak, were compared following treatment with two presently used banding methods, trypsin-Giemsa (G) and quinacrine-hydrochloride (Q) with structural bands as seen in the electron microscope, definite correlations were observed with respect to the numbers and positions of individual bands. — Weights obtained for the individual chromosomes were: No. 1, 9.89 pg; No. 2, 4.10 pg; No. 3, 4.43 pg; No. 3−X, 5.05 pg; and Y, 0.55 pg. Average diameters and weights for individual fibers were 193 Å, and 8.74×10−16g/μ, respectively, for stimulated metaphase chromosomes and 185 Å and 8.73 × 10−16 g/μ, respectively, for unstimulated chromosomes. Fibers of interphase nuclei exhibited an average diameter of 191 Å and a weight of 5.87×10−16 g/μ. — The total amount of nuclear DNA present in interphase nuclei was 3.88 pg.

OBJECTIVE CELL IMAGE ANALYSIS

A system of computer programs processes digitized images of cells. The gray value arrays are considered as a two-dimensionally extended stochastic process. Supervised learning is employed to estimate the parameters of this process in different cell types, to derive classification algorithms and to compute a likelihood for correct classification for each cell. These were found to range from 10:1 to 106:1 for tumor cells from the female genital tract. A data bank for tumor cells has been established. Nonsupervised learning algorithms are used to examine sets of cells for homogeneity. Synthesized cell images of known stochastic properties can be generated to test the completeness of the derived classification rules. Under development are programs defining the changes observable in images of a given cell type during a disease process, by the deformation of the covariance matrix of image properties.

Constancy of a 200 å fiber in human chromatin and chromosomes.

The diameter of 200 Å for modal chromatin fibers in unstimulated and stimulated peripheral human lymphocytes remains constant within a range of 5% throughout the cell cycle (including metaphase). Fiber dry mass varies slightly more, but its average of 6×10−16 g/μ. remains constant also. — The use of colchicine induces metaphase fibers to shorten and results in a fiber mass per unit length increase of up to twofold. This change does not appear to be related to any change in total chromosomal mass. Fiber shortening, consequently and, with it, shortening of the chromosome are considered to be essentially conformational events.

Three-dimensional reconstruction of a human metaphase chromosome from electron micrographs

A complete human metaphase chromosome has been reconstructed from a series of electron microscopical projections obtained by tilting the specimen stage at 3 degree intervals from −60 to +60 degrees. The reconstructed structure is about 3.0 μm long, 1.6 μm wide, and 0.8 μm thick. The mass distribution was fairly homogeneous within the chromatids and neither a hollow nor a dense core was observed. The distribution and course of fibers observed are most consistent with a looping model of chromosome structure.

EVALUATION OF CORRELATIONAL INFORMATION IN DIGITIZED CELL IMAGES

The processing of digitized cell images by computer may yield information not only about a set of cell image properties but also about their mutual dependencies. Observation of the covariance matrix of image properties of cellular material showing a response to chemotherapeutic treatment, ionizing radiation or antigenic challenge or following a developmental trend may permit a quantitative description of small trendal charges The covariance between certain cell image properties may show statistically significant changes before the mean values of the image properties are affected. Methods of reducing the dimensionality of the representation in an efficient manner are described.

Identification of a D/E(15/18) translocation chromosome by quinacrine fluorescence and Urea banding techniques

SummaryBecause of the phenotypic similarities in our patient, with 45 chromosomes including a D/E (15/18) translocation chromosome, and the 18q-syndrome patients, further chromosome identification studies with quinacrine mustard fluorescence and Urea banding techniques were undertaken. Evidence obtained from quantitation of the fluorescence patterns indicated that the clinical similarities may be due the monosomy for approximately a quarter of the long arm of chromosome 18.ZusammenfassungUnser Patient mit 45 Chromosomen und D/E (15/18)-Translokation zeigte besondere Ähnlichkeit mit Patienten des 18q-Syndroms. Deshalb wurden weitere Chromosomenuntersuchungen mit Hilfe der Fluorescenzfärbung mit Quinacrin-Mustard sowie mit der Harnstoff-Banding-Technik vorgenommen. Quantitative Auswertung der Fluorescenzmuster ergab, daß die klinischen Ähnlichkeiten durch eine Monosomie für ungefähr ein Viertel des langen Armes von Chromosom 18 verursacht sein könnten.

Herpes Simplex Virus: Dry Mass

Dry mass of herpes simplex virus particles was measured by quantitative electron microscopy after isolation by surface spreading and critical-point drying of infected cells. The core weighed about 2 x 10-16 gram, the empty naked capsid 5 x 10-16 gram, the full naked capsid 7 x 10-16 gram, and the enveloped nucleocapsid 13 x 10-16 gram.