Behavioral response to naturally occurring stress in cyclothymia and dysthymia.

Outlines an approach to epidemiologic-type life-stress studies that involves the intensive study of smaller groups of well-defined disordered individuals across the course of the response. On the basis of their previous research, the authors suggest that cyclothymia may be characterized by poor regulation of biologic and behavioral variation and that this condition may be exaggerated by stress. To extend the evidence on poor regulation generated in laboratory studies of cortisol functioning, 31 cyclothyme patients and 24 normal controls (median age 19.3 yrs) were asked to provide daily ratings of moods and events over 28 consecutive days. Data show that Ss with cyclothymia showed prolonged duration of recovery of behavioral levels compared to controls. Findings support a notion of weak inhibitory modulation in certain CNS systems that control biologic and behavioral variables related to affective disorder. It is suggested that the prolonged duration of behavioral change in cyclothymia is unlikely to be the consequence of concurrent depression and that the nature of prolonged recovery to stress in cyclothymia reflects the operation of an endogenous regulatory process, as opposed to a cognitive appraisal bias. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decreased erythrocyte Na+,K(+)-ATPase activity associated with cellular potassium loss in extremely low birth weight infants with nonoliguric hyperkalemia

To determine whether a shift of potassium ions from the intracellular space to the extracellular space accounts, in part, for the hyperkalemia seen in extremely low birth weight infants, we examined potassium concentration in serum and erythrocytes from extremely low birth weight infants with hyperkalemia (n = 12) or with normokalemia (n = 27). In addition, to determine whether the shift of potassium was associated with low sodium-potassium-adenosinetriphosphatase (Na+,K(+)-ATPase) activity, we studied the activity of ATPase in the last 16 infants enrolled in the study. Fluid intake and output were measured during the first 3 days of life. Infants were considered to have hyperkalemia if the serum potassium concentration was 6.8 mmol/L or greater. Blood was obtained daily for intracellular sodium and potassium levels by means of lysis of erythrocytes. The remaining erythrocyte membranes were frozen and analyzed for Na+,K(+)-ATPase activity. There were significantly lower intracellular potassium/serum potassium ratios in the infants with hyperkalemia for each day of the 3-day study (p < 0.001). In the hyperkalemic group, there was lower Na+,K(+)-ATPase activity than in the infants with normokalemia (p = 0.006). Low Na+,K(+)-ATPase activity was associated with lower intracellular potassium/serum potassium ratios (p = 0.006), higher serum potassium values (p = 0.02), and lower intracellular potassium concentration (p = 0.009). The urinary data demonstrated that there was no difference in glomerulotubular balance between the two groups. We conclude that nonoliguric hyperkalemia in extremely low birth weight infants may be due, in part, to a shift of potassium from the intracellular space to the extracellular space associated with a decrease in Na+,K(+)-ATPase activity.     

A behavioral paradigm for identifying persons at risk for bipolar depressive disorder: A conceptual framework and five validation studies.

Attempted to study predisposition to bipolar manic-depressive disorder by developing a behavioral paradigm to identify persons at risk for various forms of the disorder. A theoretical discussion is given for defining bipolar disorder within the broader framework of common human diseases, and this framework is used to derive dimensions of bipolar disorder that define its distinctness from the normal phenotype. These dimensions (behavioral and nonbehavioral features of disorder) are operationalized in the form of a self-report inventory that estimates the probability that an individual is at risk. Five external validation studies using nontest criteria are presented, including interview, roommate, family history, clinical characteristics, and longitudinal mood rating investigations. Results indicate that the inventory serves as a promising 1st-stage case identification procedure for bipolar disorder when employed in a research context. (2? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social support and stress during the first year of graduate school.

Describes the effects of varying levels of social interaction on 22 1st-yr graduate students' reports of stressful events and on their health and emotional problems during the 1st 6 mo of graduate study. Ss completed 2 questionnaires partially drawn from the Graduate Student Questionnaire. They also recorded their social contacts. An inverse relationship was found between frequency of social interactions with peers and faculty during the 1st 10 wks of study and the incidence of stressful life events and the number of reported physical and psychological disturbances throughout the next 6 mo. The quality of faculty–student interactions also emerged as an important factor that moderated the negative consequences of the major life changes associated with beginning graduate school. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)