A series of pooled gamete matings was carried out employing eggs and milt from mature male and female rainbow trout selected for a consistently high‐ or low‐responsiveness to stress, as indicated by post‐stress plasma cortisol elevation. Development of the progeny was closely monitored and the responsiveness to stress of the progeny of high‐responding parents and the progeny of low‐responding parents was assessed by two methods. For a period of 14 months, at approximately monthly intervals, the plasma cortisol elevation evoked by a standardized confinement stress was determined in fish from each group, and secondly, on one occasion, the time‐course of the plasma cortisol response to a 24‐h period of confinement was monitored. Progeny of high‐responding parents snowed a significantly greater cortisol response to stress than the progeny of low‐responding parents during both testing procedures. However, when the effect of a 14‐day confinement stress was examined, high‐responding progeny showed a more rapid recovery of plasma cortisol levels, while levels in the low‐responding progeny, although initially lower, showed a more sustained elevation. To assess the possible functional implications of these observations, circulating lymphocyte numbers, an immunologically important cortisol‐sensitive component of the blood cell complement, were determined. The duration of the lymphocytopenia observed following the onset of confinement was found to be related to the initial, not the sustained, cortisol response. These data suggest that manipulation of the sensitivity to stress of fish is feasible by selective breeding, but that careful.choice of the indices employed to identify traits considered desirable is necessary.

Obtaining informed consent, an ethical obligation of nurses and other health care providers, occurs routinely when patients make health care decisions. The values underlying informed consent (promotion of patients' well-being and respect for their self-determination) are embedded in the dominant American culture. Nurses who apply the USA's cultural values of informed consent when caring for patients who come from other cultures encounter some ethical dilemmas. This descriptive study, conducted with Latino, Chinese and Anglo-American cancer patients in a large, public, west-coast clinic, describes constraints on the informed consent process in a multicultural setting, including language barriers, the clinical environment, control in decision making, and conflicting desired health outcomes for health care providers and patients, and suggests some implications for nursing practice.

The accumulation of immunoreactive corticosteroids in the bile of rainbow trout during stress was monitored by radioimmunoassay and GUMS. Although plasma cortisol levels were elevated by confinement for 1 hour, biliary levels of free and conjugated steroids in the bile were unaffected. However, after 24 hours confinement, in addition to elevated plasma cortisol levels, free and conjugated steroids in the bile were also significantly higher than in control, unstressed fish. The time-course of change in plasma and biliary corticosteroid levels was determined in rainbow trout subject to 96 hours confinement stress. Free steroid levels in the bile of stressed fish were elevated within 2 hours of the onset of stress, while levels of conjugated steroids were significantly elevated within 4 hours of the onset of confinement. Analysis of bile from stressed fish, by GC/MS, established the major conjugated steroids present to be tetrahydrocortisone (230 μg ml(-1) bile), tetrahydrocortisol (75 μg ml(-1)), cortisone (33.5 μg ml(-1)), cortisol (25 μg ml(-1)) and β-cortolone (5 μg ml(-1)). The data are discussed with reference to the role of cortisone and conjugating enzymes in the clearance of cortisol, and further data are presented to suggest that the analysis of biliary steroid content may provide a suitable means of identifying stressed fish under conditions in which an additional sampling stress is unavoidable.

Colloids when frozen do not as a rule recover their original state on thawing. Stiles quotes many such cases, a well-known example being a gel of silicic acid which is separated by freezing and thawing into a mixture of water and solid flakes of acid. Similarly, when a solution of chlorophyll in water is frozen slowly, the chlorophyll on thawing is found to be aggregated into large flocks which slowly settle to the bottom. Recovery of state, however, takes place in certain systems, not necessarily the simplest, if the rate of freezing be high enough. The solution of chlorophyll furnishes an example. If it be frozen in liquid air it completely recovers its original state on thawing. Obviously the end temperature does not matter because it may be said with certainty that the frozen mass could be kept at the temperature of liquid air indefinitely without losing the capacity of reforming a solution on thawing. There must therefore exist a certain limited range of temperature within which alone the process of desolution can occur. Let us call this the critical range. The peculiar feature of any temperature within the critical range θ 1 - θ 2 is that, if the system be kept at that temperature for a critical length T of time, changes take place which are not reversed on thawing.

Plasma levels of cortisone, a steroid hormone of potential physiological significance in fish, have rarely been measured. This study examines the interrelationship between circulating levels of cortisone and the major teleost corticosteroid, cortisol, in the blood of two strains of rainbow trout subject to confinement stress, a condition know to stimulate corticosteroidogenic activity. In unstressed fish from both strains, mean plasma cortisol levels were within the range 0.4–7.5 ng ml−1. Mean plasma cortisone levels were within the range 7.1–15.9 ng ml−1. Plasma cortisol levels were elevated within 5 min of the onset of strees and reached peak values within 45 min, although there was a marked difference betweed the maxima observed in the two strains (strain 1:70 ng ml−1; strain 2:150 ng ml−1). The rate of increase of plasma cortisone levels during strees was more rapid than that of cortisol, maximum values (strain 1:100ng ml−1; strain 2:160 ng ml−1) being reached within 10 to 20 min of the onset of stress. This rapid stress‐induced elevation of plasme cortisone has not previously been reported in fish. We suggest that rapid conversion of cortisol to cortisone during the initial response to stress accounts for the appearance of large amounts of cortisone in the blood, indicating that circulating for the appearance of large amounts of cortisone in the blood, indicating that circulating levels of cortisol alone do not fully reflect the secretory activity of the interregnal during the initial of cortisol alone do not fully the secretory activity of the interregnal during the initial phase of the stress response. The results also indicate that the rate of clearance of cortisone from the circulation may be a major factor in determining stress‐stimulated levels of plasma cortisol.