Quantitative Microscopic Study Research Articles

A Quantitative Microscopic Study of Bone-Remodeling and Balance in a Human With Skeletal Fluorosis

A Quantitative Microscopic Study of Bone-Remodeling and Balance in a Human With Skeletal Fluorosis

A Semi-Automatic Computer-Microscope for the Analysis of Neuronal Morphology

Quantitative microscopic studies of individual neurons of the central nervous system, especially of their elaborate dendritic and axonal patterns, can be done only with great difficulty using conventional biological microscope instrumentation. In order to simplify and speed the gathering of such data, a computing light microscope has been developed. This instrument functions as a unit under the control of the investigator examining the histologic preparations. It is capable of measuring accurately distances in all three coordinate axes. Measurement of the length of dendrite branches is performed by means of a chord approximation. Computation is performed by means of conventional electronic analog techniques. Chord distances are computed according to the Pythagorean theorem by means of squaring, summing and square rooting. The initial coordinates of the chord are held in capacitor hold-circuits. The input to the computer section of the instrument is, by means of linear-motion transducers, fixed to the stage of the microscope along the three coordinate axes. There are two output devices, 1) a digital printer which prints on tape the distance measurements in micra (μ), and 2) a plotting board on which is drawn a two-dimensional projection (in the plane of section) of the neuron. The distances measured range roughly from 3 to 100μ, the accuracy of the measurement is ±lμ or ±9 per cent, whichever is greater. Analysis times are reduced from the approximately 24 hours required by camera lucida techniques and hand calculation to 30 min with this new instrument.

A quantitative microscopic study of certain commercial and vegetable drug starches

The existing methods employed for starch counting in starch mixtures have been studied and an improved method based upon the use of a saturated solution of zinc sulfate and a Levy blood counting slide is proposed. The selection of a suspending agent of close proximity to the specific density of starch, the latter being at the same time not altered, provided for easier handling of the sample, rapid counting, and more consistent results. Methods are described for extracting pure starch from the vegetable drugs belladonna, aconite, glycyrrhiza, and orris roots. Limitations and disadvantages of the proposed method are described.

Microscopic Historadiographic Technic for Locating and Quantitating Radioactive Elements in Tissues

Accurate quantitative microscopic studies of tissue and cellular distribution of radioactive elements which decay with emission of alpha particles may be made quite easily by the technics to be described. The essential points in the technic are (1) the use of finegrained silver-bromide emulsions with selective response to alpha radiation., (2) the mounting of tissue sections permanently on the emulsion at the beginning of the exposure. (3) examination of such preparations at 400 diameters in dark-field illumination for determination of number of alpha particle tracks per unit area of emulsion, and (4) examination of such preparations at 1000-2000 diameters for determination of the precise cellular location of the radioelement by tracing straight tracks through the emulsion to their points of origin in the tissue. The following technics have been evolved in the study of radium F (polonium) which decays with emission of alpha particles and very low intensity gamma rays. The polonium is administered in physiological saline buffered with NaHCO3. Tissues are fixed in buffered neutral 4% aqueous HCHO for 48 hours. Bones are decalcified in 5% aqueous HCOOH. Tissue blocks are dehydrated in acetone, cleared in gasoline, embedded in paraffin in a vacuum oven and sectioned at 5 μ. The ribbons are floated off cold water onto the photographic emulsion (Eastman alpha particle plate No. 329,489). All manipulations of the undeveloped photographic plates are carried out in a room illuminated by the appropriate safelight. The preparation is dried quickly in a current of air and is placed in a light-tight container for the remainder of the exposure period. At the end of the exposure period the paraffin is removed by placing the plate in xylene for 5 minutes and the plate is dried in a current of air. The plate is developed in D-19, hardened in SB-4, and fixed in F-5 (Eastman Kodak formulae) at room temperature after which it is washed in filtered tap water for 2 hours. The plate may be stained immediately or dried and stored for staining later. The plate is stained in freshly prepared Weigert's acid-iron hematoxylin for 2 minutes, washed in tap water 5 minutes, dehydrated in 3 changes of acetone, cleared in 1:1 acetone-xylene and in 3 changes of xylene. A drop of xylene-clarite is placed on the tissue and the preparation is covered with a glass coverslip.