Seymour S. Alpert

Lysosomal Defect of Hepatic Copper Excretion in Wilson's Disease (Hepatolenticular Degeneration)

After administration of 64Cu, striking differences were revealed in the copper content, specific activity, and protein binding of copper in the subcellular pools of hepatic copper in a woman with Wilsons disease compared with a control subject. None of the subcellular pools in the control subject could be identified as the source of the biliary copper, but the very low specific activity of 64Cu in lysosomes of the patient with Wilsons disease was virtually identical to that of the common duct bile and markedly different from all other subcellular pools. This suggested that lysosomes might be the source of biliary copper and that a lysosomal defect might account for the diminution of biliary copper excretion and the consequent hepatic accumulation of the metal in patients with Wilsons disease.

The concentration dependence of the hemoglobin mutual diffusion coefficient

Laser correlation spectroscopy was used to measure the mutual diffusion coefficient, D, of human cyanomethemoglobin (Fe+++:CN) at varying protein concentrations. These measurements were made at 20 degrees C in a 0.1 M phosphate buffer solution at pH 7.0. For low protein concentrations we find D = (6.43 +/- 0.26) X 10(-7) cm2/s and that there is a near linear decrease from this value at higher concentrations. The linear relation between the diffusion coefficient and protein concentration allows us to deduce the value of the linear frictional volume fraction coefficient, Kf=7.75, and to extrapolate to hemoglobin concentrations equivalent to that in the red blood cell where we estimate D = 4.25 X 10(-7) cm2/s. Various theoretical predictions of the dependence of the mutual diffusion coefficient on concentration are tested; we find that the generalized Stokes-Einstein relation can be made to fit our high concentration data if we assume a hard-sphere model and if we include a term involving a hydrodynamic interaction integral.

Light-scattering study of the temperature dependence of Escherichia coli motility

Two light-scattering techniques are used to study the temperature dependence of translational and rotational motility in Escherichia coli. The method of number fluctuation spectroscopy is developed theoretically and experimentally to measure the translational swimming speed of a smooth swimming strain of E. coli. Interference fluctuation techniques are used to study the rotational component of the motion. The results demonstrate that the thrust remains proportional the the torque generated by the flagella throughout the range studied and also show that relative changes in translational swimming speed may be inferred from the dynamics of rotational motion.

An inexpensive rotating connector for chronic intragastric infusion

Abstract This paper describes the construction of a watertight rotating connector which is made from inexpensive materials. The connector is suitable for long term intragastric infusion in freely moving rats.

A linear Fick’s law calorimeter

A small animal calorimeter is described that is based on the direct application of Fick’s law. Heat flow is channeled through a circular disk of magnesium and the temperature difference between the inside and outside surface of the disk is detected by means of solid‐state temperature transducers. The device is calibrated using a light‐weight electrical resistive source and is shown to be linear in its response and to have an e‐folding time of 4.8 min. A rat was introduced into the calorimeter and its heat energy expenditure rate was observed in both the sedated and unsedated states.