Waist Circumference Measurement by Site,Posture, Respiratory Phase,and Meal Time: Implications for Methodology

Waist circumference (WC) has been advocated as a simple, reliable, and cost‐effective measure to understand an individual's cardio‐metabolic risk. Although several protocols exist for measuring WC, the variation induced by a few factors has not been investigated. We compared several established and experimental WC measurement protocols to identify factors that may cause variations in WC measurement. In this cross‐sectional study, we examined the variations in the measurement of waist circumference (WC) measures carried out in 11 ways differing by anatomical site, posture, respiratory phase, and time since last meal, using repeated measure analysis of variance (using mixed models) after Tukey‐Kramer adjustment. We estimated the proportion of variance in percentage of body fat (%BF) and fat‐free mass (FFM) explained by each of the WC measures. We studied 123 apparently healthy Asian Indians (75 females), with mean (s.d.) age of 34 (8.7) years and BMI of 23.9 (4.8) kg/m². Overall, the mean of WCs measured using the 11 protocols were statistically different. Further, post hoc analysis showed statistically significant, yet mostly small, differences between most of the pairs. No single WC measure explained highest variance in %BF or FFM for both genders. Although, the National Institute of Health (NIH), USA, protocol was convenient and may be less prone to errors, at present it does not control for many variables tested in this study. Measures of WC measured using different protocols were statistically different. We suggest that the site of measurement, posture, phase of respiration, and time since last meal should be standardized for the development of a protocol for measurement of WC for worldwide use.     

Further evidence in support of cell-surface-associated deoxyribonucleic acid in tumor cells: an autoradiographic study.

Ascites sarcoma-180 cells, when stained with platinum-pyrimidine complexes as the sole electron dense stain, show distinct dense patches to granular appearance on the surface of the plasma membrane which has been suggested to be attributable to deoxyribonucleic acid. Swiss Webster mice, 4-5 weeks of age, weighing 24-26 g with 4 X 10(6) ascites sarcoma-180 cells when injected with 3 X 7.0 micronC of tritiated thymidine on day 5 of the tumor implant, show specific labeling on the plasma membrane surface. The photopositive silver grain distribution in both the light and electron microscope autoradiograms when followed from the nucleus outwards show a distinct peak over the nucleus and the plasma membrane. The quantity and origin and role of this surface-associated deoxyribonucleic acid is not clear.     

Cryomicroscopic determination of the membrane osmotic properties of human monocytes at subfreezing temperatures

Monocytes were isolated from fresh whole human blood and resuspended in Hanks balanced salt solution; a portion of the cells was mixed with an equal volume of 2M dimethyl sulfoxide (DMSO) to form a 1 M solution. Microliter volumes of cell suspension were placed directly onto a computer-controlled cryostage and cooled to a predetermined subzero temperature. Ice was nucleated in the extracellular medium and a continuous video record was made of the subsequent osmotically induced volume changes of individual cells owing to exposure to the concentrated extracellular solutes. Selected micrographs emphasizing the initial transient data were digitized for computer analysis with an interactive boundary tracing algorithm to determine metric parameters of specific cells, and apparent volume changes were measured as a function of elapsed time after nucleation. The Kedem-Katchalsky-coupled transport equations were fit to the data using a network thermodynamic model implemented on a microcomputer to determine values for the permeability properties Lp, omega, and sigma. Experiments were performed over the temperature range from -7 degrees to -10 degrees C. Cells pre-equilibrated with DMSO had a lower Lp and a higher activation energy, delta E, than without additive, although the statistical significance of the difference could not be substantiated. It was found that the movement of DMSO across the plasma membrane in response to extracellular freezing was apparently so much smaller than the water flux that values for omega and sigma could not be determined from the data base.