Determination of Plasma Membrane Characteristics: MATERIALS AND METHODS(2)

Electronic Particle Counter

A Coulter Counter (ZM model; Coulter Electronics, Inc., Hialeah, FL) with a standard 50-jj.m aperture tube was used for all volume measurements. Sperm cell volume was calibrated using spherical styrene beads (Duke Scientific Corporation, Palo Alto, CA) with a diameter of 3.98 ± 0.03 |xm (mean ± SEM) and a volume of 33.01 |xm3. buy ortho tri-cyclen online

Data Analysis

Membrane permeability coefficients. The Kedem Katch-alsky mass transport model was applied to determine the permeability of boar spermatozoa to CPAs. The following equations describe the total transmembrane volume flux (Jv) and permeable solute flux (Js) for a ternary solution composed of a permeable solute (glycerol, DMSO, or EG, subscript “s”) and an impermeable solute (NaCl, subscript “n”):

where V is cell volume and n‘s is the number of moles of solute (glycerol, DMSO, or EG) inside the cell, P is the hydrostatic pressure, M is osmolality and a is activity. Table 2 details the description for units, values, and symbols. In the term ms = (mes — m’s)/(lnmf — In mls), m is the concentration in molal. The superscripts “i” and “e” refer to the intra- and extracellular cell compartments, respectively. The terms Lp, PCpa> and a are parameters for the hydraulic conductivity of water, the permeability coefficient of the solute, and the reflection coefficient, respectively. The temperature and universal gas constant are given by T and R, respectively.

The relation between n[ and iris is given by:

where (V -Vb- Vs) denotes the volume of intracellular water.

TABLE 1. Composition of Modena extender.*

Ingredient Grams/liter Concentration(M)
Glucose monohydrate anhydros 27.5 0.139
Sodium citrate 6.9 0.028
Sodium bicarbonate 1.0 0.012
Ethylene dinitro tetraacetic acid (EDTA), disodium 2.35 0.007
Tris, buffer 5.65 0.047
Citric acid 2.9 0.015

* See.

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