Pathology of the superior colliculus in chronic traumatic encephalopathy

PURPOSE: To investigate neuropathological changes in the superior colliculus in chronic traumatic encephalopathy. METHODS: The densities of the tau-immunoreactive neurofibrillary tangles, neuropil threads, dot-like grains, astrocytic tangles, and neuritic plaques, together with abnormally enlarged neurons, typical neurons, vacuolation, and frequency of contacts with blood vessels, were studied across the superior colliculus from pia mater to the periaqueductal gray in eight chronic traumatic encephalopathy and six control cases. RESULTS: Tau-immunoreactive pathology was absent in the superior colliculus of controls but present in varying degrees in all chronic traumatic encephalopathy cases, significant densities of tau-immunoreactive neurofibrillary tangles, NT, or dot-like grains being present in three cases. No significant differences in overall density of the tau-immunoreactive neurofibrillary tangles, neuropil threads, dot-like grains, enlarged neurons, vacuoles, or contacts with blood vessels were observed in control and chronic traumatic encephalopathy cases, but chronic traumatic encephalopathy cases had significantly lower mean densities of neurons. The distribution of surviving neurons across the superior colliculus suggested greater neuronal loss in intermediate and lower laminae in chronic traumatic encephalopathy. Changes in density of the tau-immunoreactive pathology across the laminae were variable, but in six chronic traumatic encephalopathy cases, densities of tau-immunoreactive neurofibrillary tangles, neuropil threads, or dot-like grains were significantly greater in intermediate and lower laminae. Pathological changes were not correlated with the distribution of blood vessels. CONCLUSIONS: The data suggest significant pathology affecting the superior colliculus in a proportion of chronic traumatic encephalopathy cases with a laminar distribution which could compromise motor function rather than sensory analysis.

Quantification of axonal loss in Alzheimer’s disease: an image analysis study

The density of axons in the optic nerve, olfactory tract and corpus callosum was quantified in non-demented elderly subjects and in Alzheimer’s disease (AD) using an image analysis system. In each fibre tract, there was significant reduction in the density of axons in AD compared with non-demented subjects, the greatest reductions being observed in the olfactory tract and corpus callosum. Axonal loss in the optic nerve and olfactory tract was mainly of axons with smaller myelinated cross-sectional areas. In the corpus callosum, a reduction in the number of ‘thin’ and ‘thick’ fibres was observed in AD, but there was a proportionally greater loss of the ‘thick’ fibres. The data suggest significant degeneration of white matter fibre tracts in AD involving the smaller axons in the two sensory nerves and both large and small axons in the corpus callosum. Loss of axons in AD could reflect an associated white matter disorder and/or be secondary to neuronal degeneration.

A novel silicon membrane-based biosensing platform using distributive sensing strategy and artificial neural networks for feature analysis

A novel biosensing system based on a micromachined rectangular silicon membrane is proposed and investigated in this paper. A distributive sensing scheme is designed to monitor the dynamics of the sensing structure. An artificial neural network is used to process the measured data and to identify cell presence and density. Without specifying any particular bio-application, the investigation is mainly concentrated on the performance testing of this kind of biosensor as a general biosensing platform. The biosensing experiments on the microfabricated membranes involve seeding different cell densities onto the sensing surface of membrane, and measuring the corresponding dynamics information of each tested silicon membrane in the form of a series of frequency response functions (FRFs). All of those experiments are carried out in cell culture medium to simulate a practical working environment. The EA.hy 926 endothelial cell lines are chosen in this paper for the bio-experiments. The EA.hy 926 endothelial cell lines represent a particular class of biological particles that have irregular shapes, non-uniform density and uncertain growth behaviour, which are difficult to monitor using the traditional biosensors. The final predicted results reveal that the methodology of a neural-network based algorithm to perform the feature identification of cells from distributive sensory measurement has great potential in biosensing applications.

Individual differences in the sensory perception of fats

Excessive consumption of dietary fat is acknowledged to be a widespread problem linked to a range of medical conditions. Despite this, little is known about the specific sensory appeal held by fats and no previous published research exists concerning human perception of non-textural taste qualities in fats. This research aimed to address whether a taste component can be found in sensory perception of pure fats. It also examined whether individual differences existed in human taste responses to fat, using both aggregated data analysis methods and multidimensional scaling. Results indicated that individuals were able to detect both the primary taste qualities of sweet, salty, sour and bitter in pure processed oils and reliably ascribe their own individually-generated taste labels, suggested that a taste component may be present in human responses to fat. Individual variation appeared to exist, both in the perception of given taste qualities and in perceived intensity and preferences. A number of factors were examined in relation to such individual differences in taste perception, including age, gender, genetic sensitivity to 6-n-propylthiouracil, body mass, dietary preferences and intake, dieting behaviours and restraint. Results revealed that, to varying extents, gender, age, sensitivity to 6-n-propylthiouracil, dietary preferences, habitual dietary intake and restraint all appeared to be related to individual variation in taste responses to fat. However, in general, these differences appeared to exist in the form of differing preferences and levels of intensity with which taste qualities detected in fat were perceived, as opposed to the perception of specific taste qualities being associated with given traits or states. Equally, each of these factors appeared to exert only a limited influence upon variation in sensory responses and thus the potential for using taste responses to fats as a marker for issues such as over-consumption, obesity or eating disorder is at present limited.