Search PubMed⌕ Search

Biomedical subjects

D M Miller

Publications and source records attributed to D M Miller.

At least 253 records · Page 14Linked to original sources

Nerves originating from the cerebral ganglion of Moniliformis moniliformis (Acanthocephala).

Extending from the cerebral ganglion are the following 6 pairs of nerves: 2 pairs of anterior medial nerves, 2 pairs of lateral medial nerves, 1 pair of anterior proboscis nerves, 1 pair of lateral medial nerves. The dorsal anterior medial nerve and the ventral anterior medial nerve are unpaired nerves. The dorsal anterior medial nerve supplies the apical sensory device on the proboscis. The ventral anterior medial nerve supplies the retractor and protrusor muscles of the proboscis and the lateral posterior nerve supplies the longitudinal and circular muscles of the body wall. This last nerve is the largest of the nerves and is enclosed by the retinacular muscle as it extends through the pseudocoel to the body wall where it divides into a posterior and anterior nerve. The anterior medial nerve originates from 2 different levels along the dorsal anterior surface of the ganglion. These nerves serve the anterior presoma. The anterior proboscis nerve originates from the apical cells of the ganglion and is found between the proboscis retractor muscles throughout their length.

Acanthocephala↗

Anatomy of the cerebral ganglion of the male acanthocephalan, Moniliformis dubius.

An atlas of the cerebral ganglion of Moniliformis dubius has been constructed and the cells identified by number. There is a total of 88 cells, two of which are binucleate. These cells (20 and 90) are located in the frontal plane. The cell population is equally distributed between each half of the ganglion, there being 41 cells on each side with six cells centrally located between the two halves. Most cells give rise to bilateral processes and are organized in such a way that there is an outer coat of somata or cell bodies. Cell bodies predominate on the ventral surface, but the dorsal surface is more of a mixture of cell bodies and nerve processes. The core or neuropile occupies the central part of the ganglion and is the site for cross over for many cell processes which then exist from the side opposite the cell body. The cytoarchitecture of these cells varies considerably. Most have a large round nucleus with well defined nucleoli.

Acanthocephala↗

The kinetics of selective biological transport. V. Further data on the erythrocyte-monosaccharide transport system.

Measurements of the rate of loss of sugar from human erythrocytes into sugar-free solutions were made as a function of sugar concentrations. The half-saturation concentration of this process was found to be different from those half-saturation concentrations previously measured by other methods. These data, together with a number of similar data from former publications, are summarized in tabular form and their use in assessing postulated transport mechanisms is illustrated by consideration and rejection of a mechanism in which the transport process is assumed to be the result of a protein conformational change.

Biological Transport↗

The kinetics of selective biological transport. 3. Erythrocyte-monosaccharide transport data.

The simplest biological transport system so far extensively investigated is that of monosaccharides in human erythrocytes. Despite its simplicity there is still considerable doubt and divergence of opinion concerning its mechanism. Some confusion may arise as a result of the comparison of diverse data obtained by different workers using a variety of experimental techniques. To minimize this problem, an attempt is made here to repeat, under standard conditions and with as much care as possible, five of the more definitive types of experiments previously performed on this system. It is hoped that the result of this effort is an internally consistent set of data with which the quantitative predictions of various proposed mechanisms may be compared as a primary criterion for their acceptability.

Biological Transport↗

The kinetics of selective biological transport. IV. Assessment of three carrier systems using the erythrocyte-monosaccharide transport data.

An assessment is made of the possible validity of three transport mechanisms proposed to describe the movement of monosaccharides in human erythrocytes. These mechanisms consist of a simple carrier system and two mechanisms derived from it, one of which postulates that the free carrier moves more slowly than the complexed carrier, and the other that slow diffusion steps occur at each surface of the membrane. None of these schemes provides an adequate quantitative description of the data so that all must be discarded, leaving the question of the mechanism still open to speculation.

Biological Transport↗