Quantitative study of mitochondria in rat liver. Dry mass, wet mass, volume, and concentration of solids.

The dry mass, wet mass, and volume of mitochondria of normal rat liver were determined, as well as nitrogen content and concentration. A scheme of multiple approaches to these quantities was devised, permitting comparison of values obtained by independent methods. The following basic values are considered highly accurate: Mean dry mass, 13.6 x 10(-14) g; mean wet mass, 51.8 x 10(-14) g; mean volume, 0.43 micro(3); nitrogen content, 1.75 x 10(-14) g The work emphasizes the fact that in mitochondria the quantities, mass, and volume occur in logarithmic-normal distributions.

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.

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.

Instrumentation for the three-dimensional reconstruction of cellular organelles by electron microscopy.

Instrumental additions to the Zeiss EM-10 electron microscope are described as well as a flat-bed scanning densitometer specifically intended for the tomographic assessment of the three-dimensional structure of chromosomes. The additions to the electron microscope consist of two ion-getter pumps, reducing contamination to 0.0004 A/s. Further, a device was attached that made it possible to indicate through markers in the final negative the direction of the axis of tilt of the goniometer stage, i.e. markers indicating the tomographic axis in the digitized image. The flat-bed scanner permits correction of image rotation caused by refocusing. The preparation itself contains polystyrene latex spheres, i.e. objects the shape of which is independent of rotation (tilt). These can be used for computational corrections of the digitized image.

Reconstruction of a chromosome model from its projections.

As a pilot experiment towards the reconstruction of human chromosomes from their electron microscopic projections, a chromosome model was photographed and several cross-sectional planes successfully reconstructed. Some practical constraints and conditions for this type of work are defined.

A quality-control procedure on cervical lesions for the comparison of cytology and histology.

A new method for the quality control of cytologic and histologic diagnoses of cervical lesions is based on the automated high-resolution scanning, image processing and computer analysis of cytometric data by the TICAS system. It determines and then compares optical-density-based ploidy patterns of cells in cytologic smears and the corresponding histologic sections, with the results available both as computer-graphic displays and printouts. Examples of the former appear for an "agreement case," in which the cytologic and histologic patterns corresponded, and a noncorrespondence (nonrepresentative) case, in which the tissue sample had been nonrepresentative of the lesion sampled by cytology. Computergraphic examples concern one case of condyloma and one of tissue repair, in both of which both the cytologic and histologic diagnoses had been overcalled. A further example shows the method's use in monitoring response to therapy. The DNA ploidy patterns on which this method is based can give diagnostic and prognostic clues when morphology alone may be equivocal or insufficient. The utility of ploidy pattern determinations of material from other body sites is also well established. With the use of microprocessors, the system described could be made inexpensive and operationally simple for the routine quality control of many cytopathologic studies as well as for the clinical follow-up of patients.

Correlation of light and scanning electron microscopy a new method for exfoliative cytology.

A method for preparing locator slides for light and scanning electron microscopy has been developed. These slides make possible correlation of light and scanning electron microscopy of individual cells. Some examples of the value of this method are given.

The TICAS-RTCIP real time cell identification processor.

A preliminary model of a real time processing system, the TICAS-RTCIP (for Taxonomic Intra-Cellular Analytic System--Real Time Cell Identification Processor) has been disigned and is being tested under operational conditions, proving the substantial advantages of employing a network of microprocessors operating in parallel. The system is designed only to demonstrate the feasibility, while more extensive development and biologic testing will be required to assess general applicability to automated uterine cytology.

An automated device for the production of cell preparations suitable for automatic assessment.

A set of preparatory steps has been developed for the processing of clinical samples from the female genital tract onto microscopic slides suitable both for machine assessment and for regular microscopic evaluation. These steps involve the depositing of the cell sample in a collection fluid, the semi-automatic adjustment of cell concentration to about 30,000 cells per milliliter through a combination of transmittance and light scatter measurements, the dispersion of the sample by syringing, and the deposition of the cellular content onto microscope slides by centrifugation. These steps were designed so as not to allow loss of cells--except the lysis of erythrocytes--with the understanding that this condition entails the presence of 4--10 per cent cell aggregates in the final preparation.