Ephelides are More Related to Pigmentary Constitutional Host Factors than Solar Lentigines

Ephelides and solar lentigines are benign pigmented spots, which are currently associated with an increased risk of skin cancer. These two pigmented spots are known to be discriminated by their clinical, histological, and electron microscopic characteristics, even though occasional misclassification can occur because of their similarity. It has also been questioned whether these spots are not one and the same. In this study, we have attempted to differentiate between these two pigmented spots with the use of a standardized protocol for clinical examinations on 272 healthy volunteers, paying particular consideration to their pigmentary and constitutional host factors. We found that solar lentigines 1) are more prevalent than ephelides, 2) increase in prevalence and number with higher age, and 3) are most prevalent on the trunk and occur more frequently in males than in females. A trend is also observed whereby ephelides 1) loose their prevalence with age, 2) become equally distributed on the face, arms, and trunk, and 3) occur more frequently in females. An intimate association of ephelides, but not solar lentigines, has been found with hair color and skin type. All of these findings are in agreement with most of those reported in the literature, supporting the view that ephelides and solar lentigines are different types of pigmented lesions.     

Does boron play only a structural role in the growing tissues of higher plants?

In species in which boron (B) mobility is limited, B deficiency only occurs in growing plant organs. As a consequence of the highly localized patterns of plant growth and the general immobility of B it has been extremely difficult to determine the primary function of B in plants. In species in which B is phloem mobile, the removal of B from the growth medium results in the depletion of B present in mature leaves. Thus, it is possible to develop mature leaves with increasingly severe levels of B depletion, thereby overcoming the complications of experiments based on growing tissues. Utilizing this approach we demonstrate here that B depletion of mature plum (Prunus salicina) leaves did not result in any discernible change in leaf appearance, membrane integrity or photosynthetic capacity even though B concentrations were reduced to 6-8 µg/g dwt, which is less than 30% of the reported tissue B requirement. Boron depletion, however, results in a severe disruption of plant growth and metabolism in young growing tissues. This experimental evidence and theoretical considerations suggest that the primary and possibly sole function of B, is as a structural component of growing tissues.     

Influence of chlorophyll concentrations on the reliability of measurements with an oxygen electrode when studying photosynthetic efficiency in bioassays using microalgae

Euglena gracilis and Chlamydomonas reinhardtii were used as model organisms to establish the best conditions for studying photosynthetic efficiency using the Light Pipette – experimental system, which enables sensitive detection of changes in oxygen evolution/consumption and an easy collection and digitalisation of data. Chlorophyll concentrations of 0.005, 0.025, 0.050 and 0.075 mgmL^-1 were investigated using different light regimes. Cultures of E. gracilis at the same chlorophyll concentration absorbed more light(measured at 580 μmol m^-2 s^-1) than those of C. reinhardtii. Cell density had a considerable effect on the reliability of measurements. Chlorophyll concentrations between 0.025 mg_Chl ml^-1 and 0.050 mg_Chlml^-1 can be recommended when applying the Light Pipette system in bioassays using microalgae. This revised version was published online in August 2006 with corrections to the Cover Date.     

Correlations between the psychological peculiarities of an individual and the efficacy of a single neurofeedback session (by the EEG characteristics)

Modifications of different EEG rhythms induced by a single neurofeedback session (by the EEG characteristics) directed toward an increase in the ratio of the spectral powers (SPs) of the α vs θ oscillations were compared with the psychological characteristics of the tested subjects (the group included 30 persons). A generally accepted neurofeedback technique was used; the intensity of acoustic white noise served as the feedback signal. EEG potentials were recorded from the C3 and C4 leads. Psychological testing was carried out using Eysenck’s (EPQ), Rusalov’s (OST), and (16 PF) questionnaires. The directions of changes in the SPs of EEG frequency components were found to significantly correlate with some individuality-related peculiarities of the tested subjects. The SP of the δ rhythm correlated with the EPQ scale “neuroticism,” OST scale “social plasticity,” and 16 PF factors H (“parmia”), I (“premsia”), and Q₃ (“self-control of behavior”). The SP of the θ component demonstrated correlations with the OST scales “ergisity,” “plasticity,” and “social temp” and with 16 PF factors M (“autia”), Q₄ (“frustration”), and Q1 (“exvia”). The SP of the α rhythm correlated with 16 PF factors Q₃ (“self-control of behavior”), G (“strength of superEgo”), O (“hypothymia”), L (“protension”), and N (“shrewdness”). The SP of the β rhythm correlated with the OST scale “emotionality,” while that of the γ rhythm showed correlations with the 16 PF indices L (“protension”) and M (“autia”). Changes in the ratio of the α vs θ SPs correlated with the EPQ scale “neuroticism.” Thus, our data confirm the statement that a high individual variability of the results of a single (first in the series) neurofeedback session is to a great extent related to peculiarities of the individual psychological pattern of the subject. Neirofiziologiya/Neurophysiology, Vol. 38, No. 3, pp. 239–247, May–June, 2006.     

Environmental and genetic control of crassulacean acid metabolism in two crassulacean species and an F1 hybrid with differing biomass δ13C values

Abstract The growth, biomass δ¹³C values, and ability to accumulate titratable acidity at night were compared in eight environmental treatments for Cremnophila linguifolia, Sedum greggii, and their F₁ hybrid. In the phytotron, differences in treatment daylength, day/night temperature and water availability were all found to have effects on total plant dry weight, nocturnal accumulation of titratable acidity and biomass δ¹³C value of at least some of the genotypes. However, there were differences between the genotypes both in the magnitude and direction of response of the phenotypic properties to the treatment variables. The phytotron δ¹³C values ranged from -12.9 to -19.2‰ for C. linguifolia, from -22.2 to -33.4‰ for S. greggii, and from -19.2 to -24.9‰ for the hybrid. After with-holding water for 76 h both C. linguifolia and the hybrid had midday Ψ_leaf values of -0.23 MPa; however, S. greggii had a value of -1.05 MPa. In contrast to past observations of other species, the daily watered plants of C. linguifolia had less negative δ¹³C values than did the plants watered only weekly.