Effects of phototherapy on platelet counts in low-birthweight infants and on platelet production and life span in rabbits.

The effects of conventional phototherapy on platelets in vivo were studied in rabbits and in low-birthweight infants. Rabbits were divided into three groups and individually treated continuously for 96 hours, with blue light, daylight, or no phototherapy. Incorporation of selenomethionine Se75 was used to evaluate platelet production and life span. Platelet turnover was significantly increased in the blue-light phototherapy group, and was also increased in the daylight group but to a lesser degree. Daily platelet counts and hematocrits were performed in infants weighing less than 2,000 gm at birth randomized at 24 +/- 12 hours of life to receive daylight phototherapy continuously for 96 hours (31 infants) or no phototherapy (26 infants). In 12 treated infants (38.7%) platelet counts fell below 150,000/cu mm whereas this occurred in only 3 (11.5%) of the controls. These two lower platelet count subgroups differed significantly in mean gestational age and birthweight with the phototherapy group being the more mature. Pre-phototherapy, the mean platelet count of these 12 infants was lower than the mean of the entire control group, suggesting that these infants had borderline marrow reserve before phototherapy was given. These results suggest that phototherapy increases the rate of platelet turnover. When bone marrow compensation is inadequate, the platelet count may fall.

The chemical origin of free radicals in coffee and other beverages.

Sugars or carbohydrates are identified as the source of free radicals in coffees, ersatz coffees, a number of other food flavouring and colouring agents formed by processes involving heating, and in beers and stouts. The radicals are not derived from phenolic constituents, in contrast to those in wine, and are unlikely to be due solely to the occurrence of Maillard reactions.

Free radicals in red wine, but not in white?

By using Electron Spin Resonance (ESR) spectroscopy, we have detected free radicals in red wine, whether fermented on oak or not, and in white wine only when it has been fermented on oak. These radicals would appear to be associated with the phenolics, because the ESR signal from the residue of red wine treated with polyvinyl polypyrrolidone is reduced by approximately 80%. Any inhibition of lipid oxidation by red wine phenolics in vitro will take place in the presence of these radicals, which have a linewidth of 2.0 +/- 0.1 gauss and a g-value of 2.0038 +/- 0.0001.

Massive epistaxis from aneurysm of the carotid artery.

The syndrome of massive and sometimes fatal epistaxis from an aneurysm of the internal carotid artery is reviewed. Two cases are reported in which exsanguination occurred with anterior and posterior gauze packing in place. The use of standard methods for controlling severe epistaxis in this syndrome was a futile exercise. This distressing and frustrating experience prompted the development of an emergency method to prevent exsanguination pending definitive surgical treatment. A description of this technique is presented and a proposal made for its use.

Radiation induced EPR centers in foodstuffs and inorganic materials.

EPR investigations of a variety of irradiated materials have provided the potential for useful dosimetry applications. Herbs and spices imported into Australia have been investigated to establish whether or not they have been irradiated. Post-irradiation studies have shown that there is more than one free radical species in most cases which decay rapidly with time. Changes to transition metal ion signals, e.g., Cu2+ or Fe3+, appear to be permanent against further irradiation. Thus if these signals change upon irradiation, the material almost certainly has not previously been irradiated. Power saturation studies of alanine, a favored dosimetry material, suggest two distinguishable types of behavior consistent with the presence of spin-flip transitions. Irradiation of vanadium doped beryl yields stable VO2+ ions which may provide a useful dosimetry material. Dosimetry applications would appear to demand low cost, user friendly, automated EPR spectrometers. A patented option based on a 2.5 GHz microstrip microwave bridge will be described briefly.

Epithelial surfaces of the trachea and principal bronchi in the rat.

The epithelial surfaces in the trachea and principal bronchi of healthy rats were examined by scanning electron microscopy. A system of four cell types, ciliated, microvillous, brush, and goblet cells, in this order of frequency, were found and intermediate type cells were not seen. An extensive area of the surface examined was covered by densely ciliated epithelium. The presence of other cell types beneath the cilia was confirmed by transmission electron microscopy. Areas up to 1 mm in diameter and randomly distributed were observed where microvillous cells predominated and only occasional ciliated cells were found. Most ciliated cells in these areas were adjacent to glandular openings or goblet cells. The larger microvilli of the brush cells were arranged in a coronal configuration elucidated by the scanning electron microscope. Preparatory techniques recently introduced for the examination of soft tissue in the scanning electron microscope facilitated the confirmation of cell types present and the microarchitecture of the epithelial surface.

Estimation of the absorbed dose in radiation-processed food--1. Test of the EPR response function by a linear regression analysis.

Free radicals produced in chicken bone tissue by 137Cs gamma-rays were measured using electron paramagnetic resonance spectroscopy. The yield of radicals was found to be proportional to the absorbed dose. Additive re-irradiation of previously irradiated bones is the basis of a method to estimate the absorbed dose in radiation-processed foods. The ability of the method to provide accurate dose assessments for a range of doses (0.5-7.4 kGy) is tested here. A linear fit to the data yields reasonable dose estimates for bone irradiated less than 2 kGy, but fails at the higher doses using a linear approximation to the dose response. These data and their implications are discussed.