Fluorographic detection of radioactivity in polyacrylamide gels with the water-soluble fluor, sodium salicylate

Sodium salicylate has been found to serve as a satisfactory fluor for enhanced detection of radioactivity in polyacrylamide gels. The compound is inexpensive, water soluble, penetrates rapidly into gels, and gives linearity and sensitivity comparable to diphenyl oxazole.     

Catalogue of Human Tissue Optical Properties at Terahertz Frequencies

Recently published studies suggest thatterahertz pulsed imaging will have applications inmedicine and biology, but there iscurrently very little information about the opticalproperties of human tissue at terahertzfrequencies. Such information would be useful forpredicting the feasibility of proposedapplications, optimising acquisition protocols,providing information about variability ofhealthy tissue and supplying data for studies of theinteraction mechanisms. Research ethicscommittee approval was obtained, andmeasurements made from samples of freshlyexcised human tissue, using a broadbandterahertz pulsed imaging system comprisingfrequencies approximately 0.5 to 2.5 THz.Refractive index and linear absorptioncoefficient were found. Reproducibility wasdetermined using blood from one volunteer,which was drawn and measured on consecutivedays. Skin, adipose tissue, striatedmuscle, vein and nerve were measured (to date, from oneindividual). Water had a higher refractiveindex (2.04 ± 0.07) than any tissue.The linear absorption coefficient was higher formuscle than adipose tissue, as expectedfrom the higher hydration of muscle. As these samples camefrom a single subject, there is currentlyinsufficient statistical power to draw firmconclusions, but results suggest that in vivo clinical imaging will be feasible in certainapplications.     

Osteoporosis and Long-term Corticosteroid Therapy

Sequential measurements of total body calcium by in-vivo neutron activation analysis were made in five patients treated with corticosteroid drugs for severe inflammatory disease. No evidence of osteoporosis was seen to develop during the course of 20-33 months of study. In one case a substantial rise in total body calcium was found.     

Spatial control of rhabdom shedding in the lateral eye of the American horseshoe crab, <Emphasis Type="Italic">Limulus polyphemus</Emphasis>

Membrane leaves the rhabdom of Limulusphotoreceptors either by transient shedding at dawn or throughout the day by light-driven shedding. We examined whether the light trigger for transient shedding and the light drive for light-driven shedding are localized properties of the illuminated photoreceptors or whether they are an array property of the retina. Four experiments were conducted during which the lateral eye was exposed to one of a variety of different illumination patterns for a day, fixed, dissected and cut into serial frozen sections. Immunocytochemistry with different antibodies to Limulus opsin and arrestin revealed the results of the two processes in a distinguishable way. Eyes stimulated with whole-eye illumination had both types of shedding or just light-driven shedding when transient shedding was blocked by cutting the optic nerve. Eyes exposed to whole-eye darkness had neither type of shedding. However, when only half of an eye was exposed to light, the dark half had the same kinds of shedding as the lighted half. We conclude that the signals to trigger or drive shedding must be communicated laterally from illuminated ommatidia to unilluminated ommatidia. Rhabdom shedding is an array property.