Stress responsiveness affects dominant-subordinate relationships in rainbow trout.

The magnitude by which plasma cortisol levels increase following exposure to a stressor is a heritable trait in rainbow trout. The relative growth in coculture of F1 lines selected for high responsiveness (HR) and low responsiveness (LR) to a confinement stressor suggested that behavioral characteristics related to food acquisition, aggression, or competitive ability might differ between the two lines. This hypothesis was tested using the F2 generation of the selected lines. The F2 lines clearly exhibited the characteristics of the F1 parents, displaying significantly divergent plasma cortisol responses to a 1-h confinement stressor and a high heritability for the trait. Behavioral differences between the lines were assessed by observing the outcome of staged fights for dominance in size-matched pairs of HR and LR fish. The identification of dominant and subordinate fish within each pair on the basis of their behavior was supported by the levels of blood cortisol in the fish attributed to each group (dominant < subordinate). Fish from the LR line were identified as dominant in significantly more trials than were HR individuals. The results suggest that behavioral attributes that affect the outcome of rank-order fights are closely linked to the magnitude of the plasma cortisol response to stress in rainbow trout. Whether the link is causal or circumstantial is not yet evident.     

Urinary biomarkers for renal tract malformations

Introduction: Renal tract malformations (RTMs) are congenital anomalies of the kidneys and urinary tract, which are the major cause of end-stage renal disease in children. Using immunoassay-based approaches (ELISA, western blot), individual urinary proteins including transforming growth factor β, tumor necrosis factor and monocyte attractant proteins 1 were found to be associated to RTMs. However, only mass spectrometry (MS) based methods leading to the identification of panels of protein-based markers composed of fragments of the extracellular matrix allowed the prediction of progression of RTMs and its complications.

Areas covered: In this review, we summarized relevant studies identified in “Pubmed” using the keywords “urinary biomarkers” and “proteomics” and “renal tract malformations” or “hydronephrosis” or “ureteropelvic junction obstruction” or “posterior urethral valves” or “vesicoureteral reflux”. These publications represent studies on potential protein-based biomarkers, either individually or combined in panels, of RTMs in human and animal models.

Expert commentary: Successful use in the clinic of these protein-based biomarkers will need to involve larger scale studies to reach sufficient power. Improved performance will potentially come from combining immunoassay- and MS-based markers.     

CHARACTERIZATION OF A UNIQUE MUSCLE CELL LINE

A clonal cell line derived from a mouse neoplasm is described which shares many properties with smooth muscle. The cells have electrically excitable membranes capable of generating overshooting action potentials, and they contract both spontaneously and with electrical stimulation. They respond to the iontophoretic application of acetylcholine with a depolarizing response, and to norepinephrine with a hyperpolarizing response. Electron microscopy reveals that the cells have a morphology similar in many, but not all, respects to that of smooth muscle cells in vivo. The cells secrete soluble collagen-like molecules in addition to several proteins of undefined function. Finally, there is an increase in the specific activities of creatine phosphokinase and myokinase associated with increased cell density and the cessation of cell division.     

Respiration in relation to ion uptake in the crayfish Austropotamobius pallipes (Lereboullet).

1. O2 uptake was determined for periods of 23-46 h in salt-depleted crayfish held in deionized water (DW) or Na-free media at 10 degrees C. These media were replaced by artificial lakewater media (ALW) containing 0-2-0-6 mM Na and O2 uptake was again determined for periods of 24-66 h. 2. During net ion uptake in ALW the metabolic rate was either elevated or depressed. Standard metabolism in ALW altered by amounts equivalent to 0-1 - 15-5% (mean 6-4 (15) +/- 4-4% S. D.) of the metabolic rate measured during salt-depletion. On three occasions the metabolic rate was elevated by 22-0 - 66-7%, but some of this increase may have been due to locomotor activity. 3. The calculated values for thermodynamic work involved in ion transport were 0-056 - 0-268 J/10 g. h at 10 degrees C, or 1-5 - 7-2% of the mean standard metabolic rate. Most of the observed changes in metabolic rate lie within the limits of experimental error (ca. +/- 7%). Hence the energetic cost of ion transport is too small for direct measurement in intact crayfish.     

Experimental pulmonary infection of mice by tracheal intubation of Pseudomonas aeruginosa: the use of antineoplastic agents to overcome natural resistance.

Tracheal intubation of viable Pseudomonas aeruginosa ATCC 19660 into the lungs of mice had no significant effect on the animals even with administration of organisms as high as 5.0 X 10(9) CFU. Animals treated with a single injection of an antineoplastic drug were, however, susceptible to bacterial challenge into the lungs. LD50 values of 4.1 X 10(7), 4.8 X 10(7), and 1.0 X 10(8) CFU were obtained when animals were simultaneously infected and treated with methotrexate, vincristine sulfate, or cytosine arabinoside, respectively.     

Oxygen consumption in the fry of brown trout (Salmo trutta L.) related to pH of the water

Fry were reared in Windermere lakewater at pH 7.0 or acidified to pH 4.5–5.0. Oxygen uptake by 0.1–5.0 g fry was compared at pH 7.0 and 4.0, using artificial lakewater in the respirometer. No significant differences in oxygen uptake were found at these two pH levels. Measurements of oxygen uptake by sea trout fry ( Salmo trutta L.) at pH 7.0 are included.     

Potent dihydroquinolinone dopamine D2 partial agonist/serotonin reuptake inhibitors for the treatment of schizophrenia

A dihydroquinolinone moiety was found to be a potent serotonin reuptake inhibitor pharmacophore when combined with certain amines. This fragment was coupled with selected D₂ ligands to prepare a series of dual acting compounds with attractive in vitro profiles as dopamine D₂ partial agonists and serotonin reuptake inhibitors. Structure–activity studies revealed that the linker plays a key role in contributing to D₂ affinity, function, and SRI activity.