Density gradient electrophoresis of cells in a reversible gel.

Density gradient electrophoresis permits the separation of cell types according to surface charge density with high resolution. Any source of flow compromises the resolving power of density gradient electrophoresis. Although procedures have been devised to successfully counteract electroosmotic and convective flows, the final collection of separands requires that they be pumped out of the electrophoresis column. Experiments were therefore designed to test the hypothesis that this flow could also be eliminated by trapping the separated bands in a gel, from which they could be collected by slicing the gel cylinder. Glutaraldehyde-fixed rat and rabbit erythrocytes were used as test particles in a phosphate-buffered isotonic Ficoll-sucrose density gradient in a 2.2 cm diameter, thermostated vertical glass column that could be opened at both ends. Two types of agarose were used as gel polymers: Electrophoresis grade agarose (J.T. Baker Chemical Co.) at final concentrations of 0.1 to 0.25% and SeaPrep ultralow gelling agarose (Marine Colloids Div., FMC Corp.) at a final concentration of 1.0%. Electrophoretic separability of the test particles and fluid stability were tested independently at 55 degrees C and 32 degrees C at which the two agaroses were, respectively, liquid. The experiments demonstrated that the higher temperatures required and the presence of agarose compromised neither the stability of the density gradient nor the migration properties of the cells, and cells can be separated in a sol at a temperature that is compatible with cell viability.

A look at management roles and operating environments of medical schools.

In order to reach a better understanding of the many complexities involved in the management of schools of medicine, in 1980-81 a survey was taken of deans of medicine and department chairs of medicine, surgery, and family practice at US medical schools. The major attributes of the managerial work environment are identified and provide a foundation for further inquiry into the overall operating effectiveness of schools of medicine.

Electrokinetic alteration of the surface of herpes simplex virus infected cells.

Changes induced in the ionic composition of the surface of herpes simplex virus (HSV) infected cells were evaluated by whole cell electrophoresis and isoelectric focusing. The kinetics of the progressive decline in cell electrophoretic mobility (a measurement of negative surface charge density) after infection corresponded to the production of infection virus. The observed HSV-induced increase in cell isoelectric focusing pH demonstrated that the electrokinetic cell surface became ionically more positive. The nature of the ionic changes were investigated using a series of specific reagents in conjunction with cell electrophoresis. Infected cells had 2.4 times surface binding sites for the amino-specific reagent 4-acetamide-4'-isothiocyanostilbene-2,2'-disulphonic acid. A relationship between these virus-induced amino groups and HSV surface antigens was indicated by the similar kinetics of their appearance and electrophoretic neutralization by HSV antibodies.

Computerized, noninvasive tests of lung function. A flexible approach using mass spectrometry.

The design, operation, and some applications of a computerized pulmonary function testing system built around a mass spectrometer are described. The test sequence, performed in 10 to 20 min, includes spirometry, a single-breath N2 washout, and measurement of the diffusing capacity of the lung for CO. Secondary tests, an integral part of the sequence, include rebreathing estimates of lung volume and cardiac output, and a breath-by-breath analysis of over-all gas exchange. These secondary tests lead to computer modeling of a one-compartment lung closely matched to the subject's lungs. Differences between alveolar plateau slopes in the model and real lung provide information about the degree of ventilation-perfusion mismatch in the subject. It is expected that the combination of tests will be useful in the early detection of lung disease.

Cell electrophoresis research directed toward clinical cytodiagnosis.

The application of cell electrophoresis to cytodiagnosis requires that a scientifically established basis exists for identifying abnormal cells electrophoretically, that research to detect such differences in the cytodiagnostic setting is possible and that a rapid and simple method of cell electrophoresis is adaptable to the clinical setting. Data are presented indicating modifications of electrophoretic mobility due to herpes simplex virus type 1 infection and Rous sarcoma virus transformation of culture cells. A simple apparatus for electrophoretically separating cells on a density gradient and collecting them for subsequent analysis is described, and results of experiments with this apparatus are consistent with those obtained by microscopic electrophoresis. Laser-doppler spectroscopic electrophoresis is suggested as a rapid method adaptable to clinical application.