Effects of perfluorochemical distribution and elimination dynamics on cardiopulmonary function.

Based on a physicochemical property profile, we tested the hypothesis that different perfluorochemical (PFC) liquids may have distinct effects on intrapulmonary PFC distribution, lung function, and PFC elimination kinetics during partial liquid ventilation (PLV). Young rabbits were studied in five groups [healthy, PLV with perflubron (PFB) or with perfluorodecalin (DEC); saline lavage injury and conventional mechanical ventilation (CMV); saline lavage injury PLV with PFB or with DEC]. Arterial blood chemistry, respiratory compliance (Cr), quantitative computed tomography of PFC distribution, and PFC loss rate were assessed for 4 h. Initial distribution of PFB was more homogenous than that of DEC; over time, PFB redistributed to dependent regions whereas DEC distribution was relatively constant. PFC loss rate decreased over time in all groups, was higher with DEC than PFB, and was lower with injury. In healthy animals, arterial PO(2) (Pa(O(2))) and Cr decreased with either PFC; the decrease was greater and sustained with DEC. Lavaged animals treated with either PFC demonstrated increased Pa(O(2)), which was sustained with PFB but deteriorated with DEC. Lavaged animals treated with PFB demonstrated increased Cr, higher Pa(O(2)), and lower arterial PCO(2) than with CMV or PLV with DEC. The results indicate that 1) initial distribution and subsequent intrapulmonary redistribution of PFC are related to PFC properties; 2) PFC distribution influences PFC elimination, gas exchange, and Cr; and 3) PFC elimination, gas exchange, and Cr are influenced by PFC properties and lung condition.     

THE EXPERIMENTAL DEMONSTRATION OF PRE-MIGRATION ACTIVITY IN THE ABSENCE OF FAT DEPOSITION IN BIRDS

Under dietary conditions that experimentally prevented the accumulation of "pre-migratory" depot fat, typical nocturnal migratory restlessness developed in the Brambling Fringilla montifringilla. Subsidiary data are presented from Junco hyemalis and Zonotrichia albicollis.
In captive controls, the rapid accumulation and subsequent utilization of body fat closely paralleled the onset and waning of nocturnal unrest.
Although the Brambling accumulates fat reserves before both nuptial and contra-nuptial flights, it would seem that the presence of such is not an essential element of the so-called "total physiological state" necessary for the onset of migration.     

Environmental Challenges and Physiological Solutions: Comparative Energetic Daily Rhythms of Field Mice Populations from Different Ecosystems

Daily and seasonal variations in physiological characteristics of mammals can be considered adaptations to temporal habitat variables. Across different ecosystems, physiological adjustments are expected to be sensitive to different environmental signals such as changes in photoperiod, temperature or water and food availability; the relative importance of a particular signal being dependent on the ecosystem in question. Energy intake, oxygen consumption (VO₂) and body temperature (T_b) daily rhythms were compared between two populations of the broad-toothed field mouse Apodemus mystacinus, one from a Mediterranean and another from a sub-Alpine ecosystem. Mice were acclimated to short-day (SD) ‘winter’ and long-day (LD) ‘summer’ photoperiods under different levels of salinity simulating osmotic challenges. Mediterranean mice had higher VO₂ values than sub-Alpine mice. In addition, mice exposed to short days had higher VO₂ values when given water with a high salinity compared with mice exposed to long days. By comparison, across both populations, increasing salinity resulted in a decreased T_b in SD- but not in LD-mice. Thus, SD-mice may conserve energy by decreasing T_b during (‘winter’) conditions which are expected to be cool, whereas LD-mice might do the opposite and maintain a higher T_b during (‘summer’) conditions which are expected to be warm. LD-mice behaved to reduce energy expenditure, which might be considered a useful trait during ‘summer’ conditions. Overall, increasing salinity was a clear signal for Mediterranean-mice with resultant effects on VO₂ and T_b daily rhythms but had less of an effect on sub-Alpine mice, which were more responsive to changes in photoperiod. Results provide an insight into how different populations respond physiologically to various environmental challenges.     

PROPERTIES OF A PUTATIVE MUSCARINIC CHOLTNERGIC RECEPTOR FROM DROSOPHILA MELANOGASTER

The powerful muscarinic antagonist [³H]quinuclidinyl benzilate (QNB) specifically binds to homogenates of Drosophila melanogaster head at a level of 65 ± 6 fmol/mg protein, with an apparent dissociation constant of 0.15–0.7 nM. The half-life of the ligand-receptor complex at 25°C is 30–40 min. Binding is inhibited by low concentrations of muscarinic ligands but not by low concentrations of nicotinic ligands, anticholinesterases or non-cholinergic drugs. Binding-sites are membrane bound and are inactivated by trypsin and by Triton X-100. Part of the activity (<20%) is released into a high speed supernatant by 2 M-NaCI. The gene coding for the putative muscarinic receptor in Drosophila is apparently not located adjacent to the gene for acetylcholinesterase     

New Insights into the Role of DNA Shape on Its Recognition by p53 Proteins

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Exposure to screens of digital media devices,sleep, and concentration abilities in a sample of Israel adults

A major consequence of the invasion of digital media devices with screens equipped with light-emitting diode (LED) into bedrooms exposes the users to ongoing short wavelength (SWL) lighting during the evening and at night when under natural conditions, long wavelength are dominant. Results of several studies reveal a negative physiological, behavioral, and functional outcome of the exposure to SWL artificial light at night (ALAN) from digital media screens. The aims of our study are to assess the relationships between digital media usage, sleep patterns, subjective sleepiness, and attention abilities in adult Israeli citizens compared with Israeli adolescents. We recruited 280 adult participants using convenience sample method, 49% males and 51% females with an age range of 18–82. The participants filled out self-reporting novel and original questionnaires as follows: demographic, general health evaluation, sleep habits, and difficulties by the Pittsburgh Sleep Quality Index (PSQI) and the Karolinska Sleepiness Scale (KSS), prevalence, and usage patterns of digital media devices. Smartphones are the most used digital media device in the evening and after bedtime (the time one gets to sleep in bed). Israeli adults used smartphones for 30 min and TV for about 15 min after bedtime. We noted that excessive exposure to these devices at nighttime was associated with longer sleep latency (r = 0.192, p < 0.01) and decreased sleep hours (r = − 0.143, p < 0.05). Moreover, we found a negative correlation between attention abilities in the morning and the usage time of digital media at nighttime (r = − 0.155, p < 0.01). Exposure to digital screens at evening and nighttime was positively correlated with subjective sleepiness on the KSS (r = 0.135, p < 0.05, and r = 0.261, p < 0.01). To the best of our knowledge, this study is the first to explore the association between digital media screens usage, sleep, and concentration abilities in the Israeli adult.

     

Spectral reflectance and integrity of cell membranes and chlorophyll relative to the concentration of airborne mineral elements in a lichen

To determine the environmental impact of oil-combustion pollutants and soil dust on a lichen, we examined the spectral reflectance of thalli of the epiphytic fruticose lichen, Ramalina duriaei , expressed as values of NDVI (the normalized difference vegetation index). We analyzed electrolyte leakage caused by degradation of cell membranes in terms of electric conductivity of water, apart from chlorophyll degradation, the latter expressed as changes in the A435 nm/A415 nm ratio to indicate the physiological status of the lichen. The concentrations of Al, Cr, Fe, K, Ni, P, sulfate-S, Ti and V in the lichen thallus were measured to quantify the degree of pollution. Thalli of R. duriaei , growing in a nature reserve on the periphery of a 40-year-old industrial town, Ashdod, in southwest Israel were compared with thalli of R. duriaei from an unpolluted forest in the northeastern part of the country transplanted to the polluted areas in and around the town. After an exposure for 10 months, many transplants exhibited lower NDVI values, higher electric conductivity values as well as a lower A435 nm/A415 nm ratio. The three physical/physiological parameters thus reflected severe injury in the lichen transplants. The concentrations of Al, Cr, Fe, Ni, sulfate-S, Ti and V in the lichen transplants were found to correlate inversely with the NDVI values, whereas the concentrations of Fe, Ni, Ti and V were found to correlate with electric conductivity. The decrease in the A435 nm/A415 nm ratio was found to correlate with high concentrations of Al, Fe, Ni, sulfate-S, Ti and V in the lichen transplants, whereas the concentration of K and P correlated with both the NDVI value and the A435 nm/A415 nm ratio. It is concluded that in situ thalli of R. duriaei , the only indigenous fruticose lichen growing in the region of Ashdod, are endangered by the presence of pollutants and by acid rain due to the combustion of heavy fuel oil.