TRH-induced reflex changes in patients with ALS

A trial of Thyrotropin Releasing Hormone (TRH) 5.0 mg/kg body weight subcutaneously every other day for two weeks produced transient increased tone in muscles, along with other (side-) effects in patients with Amyotrophic Lateral Sclerosis (ALS). One patient's extensor plantar transiently changed to a flexor plantar reflex after injection, probably due to disproportionate increase in tone of the calf muscles. No significant changes in F-waves or H-reflexes were seen. No increase in useful voluntary strength, or in strength measured by Medical Research Council (MRC) testing or strain gauge isometric strength testing was seen. However, dyspnea was seen within 10 minutes of TRH injection.     

A comparison study of dynamic visual acuity between athletes and nonathletes

A comparison study of dynamic visual acuity (DVA) was conducted using samples of nonathletic college students and college baseball players. The experimental population consisted of 17 male baseball players ranging in age from 19-24 years. The control population was made up of 25 male graduate students ranging in age from 23-29 years. Subjects reported the direction of a 20/25 "Landolt C" target exhibiting uniform angular motion produced by a projection system. Angular target velocities between 10 deg/sec and 110 deg/sec with an exposure time of 400 ms were used. The results showed a statistically significant difference between the two groups' DVA. The mean DVA for the baseball players was 82.35 deg/sec and 69.90 deg/sec for the control group.     

Competitive control of the self-renewing T cell repertoire

We develop a mathematical model for the self-renewing part of the T cell repertoire. Assuming that self-renewing T cells have to be stimulated by immunogenic MHC-peptide complexes presented on the surfaces of antigen-presenting cells, we derive a model of T cell growth in which competition for MHC-peptide complexes limits T cell clone sizes and regulates the total number of self-renewing T cells in the animal. We show that for a sufficient diversity and/or degree of cross-reactivity, the total T cell number hardly depends upon the diversity of the T cell repertoire or the diversity of the set of presented peptides. Conversely, for repertoires of lower diversity and/or cross-reactivity, steady-state total T cell numbers may be limited by the diversity of the T cells. This provides a possible explanation for the limited repertoire expansion in some, but not all, mouse T cell re-constitution experiments. We suggest that the competitive interactions described by our model underlie the normal T cells numbers observed in transgenic mice, germ-free mice and various knockout mice.