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C. maenas, an osmotic and ionic conformer at high salinity (32 - 40 ppt), makes a transition to osmotic and ionic regulation at 10 ppt; hemolymph concentrations stabilize by 6 - 12 h at values significantly above those in the medium Carbonic anhydrase (CA) activity, which is low and uniformly distributed across all gills at 32 ppt, is induced 7 fold in gills 6 - 9. Induction is initiated at 4 days post-transfer and is complete by 7-14 days. CA inhibition by acetazolamide causes decreased hemolymph osmotic and ionic concentrations at 10 but not 32 ppt. Branchial Na/K ATPase activity is low in all gills at 40 ppt but is induced in G6 - 9 at 32 ppt and does not increase at 10 ppt. High Na/K ATPase values may be related to the crab's intertidal habitat in which rapid and unpredictable dilutions can occur. Supported by NSF 97-27835 and by the Salsbury Cove Research Foundation.

In euryhaline crabs, ion-transporting cells are clustered into osmoregulatory patches on the lamellae of the posterior gills. To examine changes in the branchial osmoregulatory patch in the blue crab Callinectes sapidus in response to change in salinity and to correlate these changes with other osmoregulatory responses, crabs were acclimated to a range of salinities between 10 and 35 ppt. When crabs that had been acclimated to 35 ppt were subsequently transferred to 10 ppt, both the size of the osmoregulatory patch on individual gill lamellae and the specific activity of Na+, K+-ATPase in whole-gill homogenatas increased only after the first 24 h of exposure to dilute seawater. Enzyme activity and size of patch area increased gradually and reached their maxima (increasing by 200% and 60%, respectively) 6 days following transfer to 10 ppt seawater and then remained at these levels. Patch size at acclimation varied inversely with the salinity for seawater dilutions below 26 ppt (the isosmotic point of the crab), although it did not vary in salinities at or above 26 ppt. Thus, the size of the patch clearly is modulated with acclimation salinity, but it increases only in those salinities in which the crab hyperosmoregulates. An increase in the total RNA/DNA ratio in gill homogenates, the lack of mitotic figures in the lamellae, and the lack of incorporation of bromodeoxyuridine into nuclei of lamellar epithelial cells during acclimation to dilute seawater were interpreted as evidence that no cell proliferation had occurred and that increases in the size of the osmoregulatory patch occurred through differentiation of existing gas exchange cells or of undifferentiated epithelial cells into ion-transporting cells. [ABSTRACT FROM AUTHOR]

Hemocyanin, the blue blood protein of many arthropods and molluscs, reversibly binds oxygen at its highly conserved copper-oxygen-binding sites and supplies tissues with oxygen. Cryptocyanin, closely related structurally and phylogenetically to arthropod hemocyanin, lacks several of the six critical copper-binding histidines, however, and has lost the ability to bind oxygen. Despite this loss of function, cryptocyanin continues to be synthesized, an indication that it has been exploited to carry out new functions. Here, we show that cryptocyanin is present in extremely high concentrations in the hemolymph of the crab during the premolt portion of the molt cycle. Both proteins are specifically expressed in the same type of cell in the hepatopancreas and secreted into the hemolymph, but cryptocyanin plays a major role in forming the new exoskeleton, while hemocyanin functions in oxygen transport. A cessation in cryptocyanin, but not hemocyanin, synthesis after eyestalk ablation supports our hypothesis that cryptocyanin is closely regulated by molting hormones. The contrasts between the two gene products illustrate how a gene duplication of a copper-oxygen protein and its subsequent mutation may work in concert with the evolution of new regulatory mechanisms, leading to the assumption of new functions. [ABSTRACT FROM AUTHOR]

The present study reports on the use of computer-presented games, designed to retrain memory abilities, with memory-impaired stroke patients. Eleven patients underwent a six-week treatment course consisting of practice on computerized games for 40 minutes a day, up to a maximum of four times a week. The patients were assessed on objective memory tasks before and after treatment. Seven patients showed improvements of one standard deviation or more on at least one of the outcome measures, but as a group significant improvement was found only on the immediate recall form of the Prose Recall task. It appears that specific memory skills are learned as a result of treatment, but these skills generalize poorly to untrained memory tasks. The patients' patterns of cognitive deficits affect performance and this type of retraining may not be suitable for all stroke survivors. The study emphasizes the need for evaluation of computer-based cognitive rehabilitation. [ABSTRACT FROM PUBLISHER]

OBJECTIVE To compare the provision of health and social services between a social work intervention and non-intervention group. DESIGN Depressed stroke patients were randomly assigned to either an intervention or non-intervention group. Over a 4 month period both groups were visited three times by an independent assessor who rated them on service provision and functional independence. SETTING Patients' homes. PATIENTS 44 depressed stroke patients. INTERVENTION Both groups were given an information booklet and the intervention group were then visited regularly by a research social worker over a period of 4 months. The social worker adopted a pragmatic approach which included providing counselling and information on services and benefits. MAIN RESULTS The study groups did not differ in level of social independence (p greater than 0.05) or total number of financial benefits (p greater than 0.05), services (p greater than 0.05) or aids (p greater than 0.05) received either before or after intervention. When the results from the two groups were combined, home help and meals-on-wheels were the most frequently provided services (25% of patients). Walking aids (72% of patients) and bath aids (59% of patients) were the most frequently provided aids to daily living. CONCLUSION Social work assistance had little effect on service provision or level of functional independence. [ABSTRACT FROM AUTHOR]

This paper reports the results of measurements of the attenuation and velocity of ultrasonic waves in various liquid media as a function of the intensity level at the detector of the radiation. The attenuation in distilled water and dilute solutions of acetic acid and sodium acetate is found to increase almost linearly with the acoustic excess pressure amplitude in the range from 2 to 7 atmospheres, for frequencies of 4, 5, 7, and 9 megacycles/sec. The attenuation in glycerine shows a similar increase when correction is made for the unavoidable rise in temperature of the medium. The rate of increase is found to be practically independent of frequency in the range employed, thus disagreeing with the prediction of R. D. Fay's theory of the attenuation of high-amplitude plane waves. No change of velocity with source intensity has been observed. [ABSTRACT FROM AUTHOR]