Increased Vulnerability to Stress Following Opiate Exposures: Behavioral and Autonomic Correlates.

The authors used rats to study the impact of a history of opiate exposures on behavioral and autonomic responses to restraint stress. Brief restraint (30 min) provoked tachycardia and a pressor response, anxiety (as indexed by social interaction), grooming, and reduced exploration. The pressor response was reduced at 1 day, but not 7 days, after last opiate exposure; tachycardia was unaffected (Experiment 1). Stress-induced anxiety was potentiated 1 and 7 days after last opiate exposure (Experiment 2), and this potentiation was a function of dose (Experiment 3) and duration (Experiment 4) of opiate exposure. The results show that a history of opiate exposures alters vulnerability to stress and has implications for understanding coping, anxiety, and emotionality in former opiate users. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experiences of depression in normal young adults.

Investigated depression as a normal affect state that could have continuity with types of clinical depression. A 66-item Depressive Experiences Questionnaire (DEQ) was constructed to assess a wide range of experiences that, though not direct symptoms of depression, are frequently associated with it. The DEQ, the Wessman-Ricks Mood Scale, a version of the semantic differential, and the Death-Concern Questionnaire were administered to 500 female and 160 male college students. In another sample, 128 college students were given the DEQ and the Zung Self-Rating Depression Scale. Three highly stable factors emerged from the DEQ: Dependency, Self-Criticism, and Efficacy. These factors had significant differential correlations with other measures, which support the interpretation of the factors derived from the items. These data indicate the need to consider dependency and self-criticism as 2 primary dimensions of depression and the value of investigating the continuity between normal mood states and the clinical phenomena of depressions. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Present morality in parkinson's disease: the ratio of observed to expected deaths with a method to calculate expected deaths

Excess mortality, i.e. more deaths than expected in a similar normal population, has been reduced in Parkinson's disease by levodopa. A California series and a large collaborative study throughout the United States show the ratio of observed to expected deaths to be normal. In contrast, a New York study was similar patients and a Montreal group of much more severely disabled patients showed greater mortality. The reasons for these differences are unclear, but some variations in results may be attributed to different methods of calculating expected deaths to derive the ratio of observed to expected deaths.     

Arterial blood gases in acute pulmonary edema

Arterial blood gas and pH measurements in 82 patients with acute pulmonary edema of cardiogenic origin entering the emergency department varied widely and were unpredictable using clinical examination. The mean arterial oxygen tension (PaO2) measured in 71 patients breathing room air was 59 mm Hg. Fourteen of the 82 patients were acidemic; 35, alkalemic and 33 had a pH in the normal range. The acidemic group had markedly lower PaO2, all under 60 mm Hg. Oxygen and furosemide were used in all cases and effectively corrected the hypoxia and reduced pulmonary congestion. Other drugs used included aminophylline (14 patients), morphine sulfate (9 patients) and digoxin (3 patients). Five of the nine patients who received morphine were hypercarbic initially but the CO2 retention did not worsen. No patient died during the initial 48 hours. This study reiterates the importance of directing therapy at ventilatory and cardiac abnormalities and points out the value of arterial blood gas monitoring to assess the initial status, monitor the patient's course, and to select drug therapy.     

Assessment of the risk of solar ultraviolet radiation to amphibians. I. Dose-dependent induction of hindlimb malformations in the northern leopard frog (Rana pipiens)

A number of environmental stressors have been hypothesized as responsible for recent increases in limb malformations in several species of North American amphibians. The purpose of this study was to generate dose-response data suitable for assessing the potential role of solar ultraviolet (UV) radiation in causing limb malformations in a species in which this phenomenon seemingly is particularly prevalent, the northern leopard frog (Rana pipiens). Frogs were exposed from early embryonic stages through complete metamorphosis to varying natural sunlight regimes, including unaltered (100%) sunlight, sunlight subjected to neutral density filtration to achieve relative intensities of 85%, 75%, 65%, 50%, and 25% of unaltered sunlight, and sunlight filtered with glass or acrylamide to attenuate, respectively, the UVB (290-320 nm) and UVB plus UVA (290-380 nm) portions of the spectrum. The experiments were conducted in a controlled setting, with continual monitoring of UVB, UVA, and visible light to support a robust exposure assessment. Full sunlight caused approximately 50% mortality of the frogs during early larval development; no significant treatment-related mortality occurred under any of the other exposure regimes, including 100% sunlight with glass or acrylamide filtration. There was a dose-dependent (p < 0.0001) induction of hindlimb malformations in the frogs, with the percentage of affected animals ranging from about 97% under unaltered sunlight to 0% in the 25% neutral density treatment. Malformations were comprised mostly of missing or truncated digits, and generally were bilateral as well as symmetrical. Filtration of sunlight with either glass or acrylamide both significantly reduced the incidence of malformed limbs. The estimated sunlight dose resulting in a 50% limb malformation rate (ED50) was 63.5%. The limb ED50 values based on measured sunlight intensities corresponded to average daily doses of 4.5 and 100 Wh x m(-2) for UVB and UVA, respectively. Exposure to sunlight also resulted in increased eye malformations in R. pipiens, however, the dose-response relationship for this endpoint was not monotonic. The results of this study, in conjunction with measured or predicted exposure data from natural settings, provide a basis for quantitative prediction of the risk of solar UV radiation to amphibians.     

Selenoprotein deficiency enhances radiation-induced micronuclei formation

The availability of selenium and the levels of specific selenoproteins might affect cancer risk by influencing the ability of DNA damaging agents to cause genomic instability and mutations. Transgenic mice that express reduced levels of selenoproteins and previously shown to be more susceptible to pathology associated with cancer development were used to study this possibility. These mice were exposed to X-rays and DNA damage assessed in the erythrocytes, where micronuclei formation was higher compared to the same cells obtained from irradiated wild-type controls. To determine whether the selenoprotein glutathione peroxidase-1 (GPx-1) might be involved in this protection, its levels were reduced by siRNA targeting in LNCaP human prostate cells. UV-induced micronuclei frequency was higher in these cells compared to control-transfected cells. These results indicate a role for selenoproteins in protecting DNA from damage and support human data implicating GPx-1 as a possible target of the chemoprotective effect of selenium.     

Increasing hypnotic susceptibility by means of positive expectancies and written instructions.

Investigated the extent to which hypnotic susceptibility could be modified by means of induced positive expectancies and written instructions that were designed to correct misconceptions concerning hypnosis as well as to provide concrete methods for experiencing hypnosis. 40 undergraduates were given a baseline test of hypnotic susceptibility and then randomly assigned to 1 of 4 conditions. Ss receiving the positive expectancy were given false personality test feedback that they were good hypnotic Ss prior to a criterion hypnotic scale. Ss receiving the written instructions were given 10 min to read the information prior to the hypnotic test. Other Ss browsed through magazines prior to testing in hypnosis. Both positive expectancies and written instructions were significantly effective in increasing susceptibility in comparison with practice only. Theoretical explanations are advanced and the implications of these findings are considered. (26 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)