Jehu Hunter

Effects of insulin on melanoma and brain metabolism

Both brain and melanoma slices displayed similar QO2CO2 values, but marked differences occurred in QN2CO2 under certain conditions. Thus, the two tissues responded differently to added magnesium, phenol, and insulin. The first two substances markedly increased the QN2CO2 of brain but slightly inhibited that of melanoma. The QN2CO2 of brain slides was not increased by insulin but that of melanoma was (ca. 40%). As little as 0.003 mg (0.1 units) of crystalline zinc-insulin per ml was sufficient to give maximal stimulation. Crystalline zinc-insulin freed of hyperglycemic factor was as effective as regular crystalline zinc-insulin in increasing the QN2CO2 of melanoma slices. Hyperglycemic factor largely freed of insulin had no appreciable effect on QN2CO2. Zinc appears to play a critical role in connection with the influence of insulin on QN2CO2 of melanoma slices. The relative concentrations of the two substances are critical. Under aerobic conditions insulin variably increased the R.Q., QO2CO2, and absolute Pasteur effect of melanoma. QO2 (respiration) was never increased, but was sometimes decreased. Exposure of melanoma-bearing mice to 35° or 40° C, for 13 hours or more, was associated with a marked diminution in the QN2CO2 of the tumor slices as compared to tumor slices from mice exposed to ca. 20° C. Insulin increased (average 49%) the QN2CO2 of slices from the heat-treated tumors to a level approximately equal to that of slices from 20° C tumors where insulin gave only slight stimulation (average 7%); additional (12 to 44 days) exposure to 35° or 40° C resulted in marked suppression of tumor growth and further decline in the QN2CO2.

Summary statements of the NIH Nursing Research Grant Applications.

Summary statements from the Nursing Research Study Section, Division of Research Grants, NIH, between October, 1986 and June, 1988 were used to identify reasons for recommending approval or disapproval of grant applications with RO1 and R29 activity codes. The 917 comments (25 ± 4 per critique), sorted into one of nine categories (Aims, Significance, Investigator, Budget, Resources, Design, Sample, Techniques, Data Analysis) for analysis, were classified as Strengths (positive comments) or Weaknesses (negative comments). The weaknesses of approved applications were confined mostly to the categories of Design and Techniques. Disapproved applications had few strengths and many weaknesses in Design, Sample, Techniques, and Data Analysis. Critiques of First Award (R29) and traditional research project grant applications (RO1) were similar. The approved applications addressed meaningful problems, had well-synthesized literature reviews, and were solvable by available techniques. The research plans were consonant with stated aims, and the methods sections reflected understanding of the principles underlying the techniques to be used. A supportive environment and adequate research resources, including access to the study population were common to these applications. Disapproved applications provided poor synthesis of the literature, methods inconsistent with the aims, and often reflected inadequate understanding of techniques to be used.

Observations and reflections on manometric calibrations with air: Methods for indolent mercurophobes

Abstract Methods approaching the ultimate in simplicity, accuracy, reproducibility, and rapidity have been described for the calibration of manometric vessel and capillary volumes with either known or unknown volumes of air, withdrawn from or added to the test manometer system by means of a precalibrated reference standard manometer system (or other equivalent precalibrated device) connected by tubing to the test manometer. Two fundamental steps of procedure are employed, in accordance with Boyles law, to obtain measurements applicable in two simultaneous equations for two unique conditions of simplicity, the one at constant pressure, the other at constant volume. In the first step, after initial equilibration, the standardizing volume of air is transferred between standard (∗) and test manometer with releveling to constant initial pressure (Δ P = 0), yielding a determination of v , the capillary volume per specified length, from no more than simple inverse proportionality between the observed capillary fluid length changes ( v = v ∗ L ∗ L ). In the second step the manometers are closed off at their stopcocks and the confined gases brought back to their initial space volumes (Δ V = 0), yielding a determination of the vessel gas space volume v g , from no more than simple inverse proportionality between the observed capillary fluid pressure changes ( v g = v g ∗ h ∗ h ). v ∗ and v g ∗ are previously known from the standard manometer, L ∗ and h ∗ are obtained with it, and L and h with the test manometer. Our most recommended procedures for measuring manometric capillary ( v ) and vessel ( V ) values (Eqs. (1′) and (5) with known volumes of air, see Table I, and Fig 1, and Eqs. (1′ u ) and (5 u ) with unknown volumes) require no (numerical) knowledge of barometric pressure, watervap or pressure, absolute temperature, “dead space” of connecting tubes, solubility of air in water, etc., apart from assurance of maintenance of their constancy during manipulations. These factors and other second- and third-order effects (difference in draining of capillaries, changes in dissolved air with pressure changes, differences of temperature outside and inside the thermostat) that enter into applied manometry, are in principle rendered negligible by the differential methodology of our procedure of calibrating a test manometer with another (precalibrated) manometer. The accuracy and reproducibility of these air calibrations can be adjusted, depending upon the will and the skill of the investigator, either to the maximum attainable in operating manometry (say ± 0.2%), or to an accuracy as good or better than that employed in 95 % of all manometry, namely ±1 %. Methods for the minimization or actual elimination of thermobarometric (TB) changes, an important factor largely neglected in previously described methodology of air calibration, are outlined. The outer manometer arms are not left open to the external atmosphere, but are connected with a large vessel (e.g., a 20-l. carboy) whose pressure can be manipulated (as by a large connected syringe) so that any effects of pressure or temperature variations can be readily restored to precisely zero in the TB manometer, and simultaneously thereby in all other manometers connected in parallel. The uses and advantages of such a carboysyringe device in not only calibration, but even more importantly and generally, in many aspects of operative manometry, are indicated. No manometric laboratory should be without such a device (see Fig 1). The proposed methodology is recommended to all indolent mercurophobes and aerophiles, for whom the gravity of the problem of mercury calibration is herewith reduced by the levity of air, and a little air of levity.