Disease from the point of view of evolution

In the process of evolution, such compensatory reactions as enhanced absorption of sodium chloride and an increase of arterial pressure could be formed only for compensation of acute pathological states (blood loss, dehydration). At present they remain similarly adequate in acute disturbances of blood circulation and of water-electrolyte balance. However, in severe chronic pathology of heart and kidney they often lose their compensatory function and even become dangerous. Evolution of man and of human society has created novel social conditions of adaptation. They are of humanitarian and technogenic character by promoting prevention and treatment of diseases.     

Uncoupling proteins: the issues from a biochemist point of view

The functional characteristics of uncoupling proteins (UCP) are reviewed, with the main focus on the results with isolated and reconstituted proteins. UCP1 from brown adipose tissue, the paradigm of the UCP subfamily, is treated in more detail. The issues addressed are the role and mechanism of fatty acids, the nucleotide binding, the regulation by pH and the identification by mutagenesis of residues involved in these functions. The transport and regulatory functions of UCP2 and 3 are reviewed in comparison to UCP1. The inconsistencies of a proposed nucleotide insensitive H(+) transport by these UCPs as concluded from the expression in yeast and Escherichia coli are elucidated. In both expression system UCP 2 and 3 are not in or cannot be converted to a functionally native state and thus also for these UCPs a nucleotide regulated H (+) transport is postulated.     

On the theory of cell division from the point of view of the principle of maximum energy exchange

An analysis is made of the equation of cellular elongation during division, which was derived by N. Rashevsky from the principle of maximum energy exchange. The method used is the same as that employed by H. D. Landahl in discussing a similar equation deduced from the theory of diffusion drag forces. The differential equation is expanded in a power series of the relative elongation, and in this way is reduced to the form studied by H. D. Landahl, which has been shown to agree very well with experimental data. An estimate of the order of magnitude of the universal constant τ, which appears in the generalized Hamiltonian principle, is made, and τ is found to be of the order of 10⁻⁴ sec.     

Hydrodynamics of larval settlement from a larva's point of view

Many benthic marine invertebrate animals release larvae that are dispersed by ocean currents. These larvae swim and can respond to environmental factors such as chemical cues. However, larvae are so small (generally 0.01-1 mm) that they are often assumed to be passive particles whose trajectories are determined by the motion of the water in which they are riding. Therefore, marine larvae are useful model organisms to study the more general question of how the locomotion of very small animals in complex, variable natural habitats is affected by the motion of the fluid (water or air) around them. Studying larval locomotion under conditions of water flow encountered in nature is challenging because measuring the behavior of an individual microscopic organism requires high magnification imaging that is difficult to do in the field. The purpose of this article is to synthesize in one place the various approaches that we have been using to address the technical challenges of studying the locomotion of microscopic larvae in realistic ambient flow. The steps in our process include: (1) measuring water flow in the field; (2) mimicking realistic water movement in laboratory flumes to measure larval scale fluctuations in velocity of flow and concentration of chemical cues; (3) mimicking fine scale temporal patterns of larval encounters with a dissolved chemical cue to record larval responses; (4) using individual-based models to put larvae back into the larger scale environmental flow to determine trajectories; and (5) mimicking fine scale spatial and temporal patterns of larval encounters with water velocities and shear to determine the instantaneous forces on larvae. We illustrate these techniques using examples from our ongoing research on the settlement of larvae onto fouling communities and from our published work on settlement of larvae onto coral reefs. These examples show that water velocities and concentrations of chemical cues encountered by microscopic organisms can fluctuate in fractions of a second and vary over scales of less than a millimeter.     

The human embryo: a scientist's point of view

...Thus, my judgement is that a human embryo is not a human person, and so we may do experiments on it which involve killing it. But my judgement is also that a human embryo has the potential to become a human being. The consequence of this attribute is that it imposes limits on the kinds of experiments which may be performed on human embryos. It is this which sets the boundaries. Experiments which may harm the embryo while still allowing it subsequently to realise its potential, and become a person, should not be permitted. It is the potentiality of the human embryo which governs our behaviour towards it. Its potential makes it special, and radically different from any other human tissue. This potential which the early embryo has means that great respect must always be accorded it, and great thought and care must surround any dealings with it....