A screw-connected fixed partial denture.

This technique provides one solution to the problem of using tilted abutment teeth for a fixed partial denture. It provides good retention without excessive tooth destruction and without excessive contour in the completed restoration.

Calcium in long-term potentiation as a model for memory.

The granule, CA1 and CA3 cells of the hippocampus have been much investigated during the last decade because there is superimposed on the standard features of synaptic transmission a very prolonged potentiation lasting for weeks that is called long-term potentiation. Evidently long-term potentiation is a promising candidate in the construction of a model for memory. The thesis here developed is that the influx of calcium ions across the membrane of the granule pyramidal cells plays the key role in the generation of long-term potentiation.

Charged amino acids as spectroscopic determinants for chlorophyll in vivo.

In this paper we propose that the large spectroscopic red shifts observed for chlorophyll (Chl) and bacteriochlorophyll (BChl) in vivo may be due to charged amino acids in the binding site. Molecular orbital calculations of the transition energies of Chl in the field of external charges are carried out. The calculated wavelength shifts induced by these charges are comparable in magnitude to those observed in vivo.

The horizontal (tangential) fibres system of lamina I of the cerebral neocortex.

Lamina I has two principal components: a meshwork of fine unmyelinated fibres, the so-called horizontal fibres (h.f.); the profusely branching apical dendrites of all pyramidal cells.

The liaison brain for voluntary movement: the supplementary motor area.

An account of the origin of the term liaison brain leads on to an historical account of its usage, particularly in voluntary movement. Empirical evidence was provided by the readiness potential of Kornhuber and associates, which even indicated a key role for the supplementary motor area, SMA. It was found by Brinkman and Porter that in voluntary movement many neurones of the SMA were activated probably up to 200 msec before the pyramidal tract discharge.

The initiation of voluntary movements by the supplementary motor area.

The hypothesis is formulated that in all voluntary movements the initial neuronal event is in the supplementary motor areas (SMA) of both cerebral hemispheres. Experimental support is provided by three lines of evidence. 1.

Some circuit operations in the mammalian brain.

There is an account of the basis neuronal connectivities of the spinal cord with the Sherringtonian principles of divergence and convergence. Neurones act synaptically either as excitatory or as inhibitory, depending on the specific transmitter substances liberated. Inhibitory neurones usually act either in a feedback or a feedforward manner.

Salmonella in the intestinal tract and associated lymph nodes of sheep and cattle.

The distribution of salmonellas along the gastrointestinal tract and in associated lymph nodes were studied in 100 sheep and 100 cattle at slaughter. Animals were chosen from those slaughtered on the first day of the week, since this meant that they were likely to have been held at the abattoir for several days and thus to be at high risk of salmonella infection. The contents of the rumen, abomasum, ileum, caecum and rectum were sampled, together with the lymph nodes draining each of these sites.

Physiology of motor control in man.

The physiology of motor control is considered in hierarchical terms. In that way it is possible to gain insight into the complex superimposed systems of motor control. In the execution of a voluntary movement the neural machinery is called into operation at all of the hierarchical levels: (1) the motor unit; (2) spinal reflex mechanisms; (3) brain stem mechanisms; (4) cerebellar vermis controls; cerebrocerebellar controls, (5) via the pars intermedia and (6) via the cerebellar hemispheres and also of the basal ganglia.

Dental erosion of nonindustrial origin. A clinical survey and classification.

A survey was made from the clinical records of 72 patients diagnosed as suffering from dental erosion of nonindustrial origin. The information surveyed included dietary history, relevant medical history, clinical examination, and color photographs of the affected teeth. A new classification of erosion is proposed and the different types of lesions are described.