Rationale Social interaction during drug exposure can potentiate cocaine reward. Isolation rearing (ISO) during adolescence increases social interaction and may amplify this potentiation. Objectives The objectives of this study are to determine whether ISO alters conditioned place preference (CPP) for cocaine when combined with a social cue and to determine whether ISO alters the effects of cocaine when combined with social cue on nucleus accumbens shell (NAcS) dopamine (DA) and serotonin (5-HT). Methods Male and female rats were either ISO or group (GRP) reared for 4 weeks during adolescence. CPP was performed using a low dose of cocaine (2 mg/kg or saline) with or without exposure to a novel same-sex conspecific during conditioning. In vivo microdialysis was performed using the same parameters. Results ISO rats engaged in more social and aggressive behaviors during conditioning relative to GRP. Cocaine reduced social and aggressive behaviors in all rats. CPP was not influenced by rearing condition. Cocaine produced significant CPP, and a social cue produced CPP only in males. In contrast, the interaction of cocaine and a social cue on NAcS DA and 5-HT differed depending upon rearing condition. In isolates, cocaine-induced DA was attenuated, while cocaine plus a social cue produced potentiated DA and 5-HT. Conclusions Exposure to a low dose of cocaine in the presence of a social cue produced additive effects on CPP while producing synergistic effects on DA and 5-HT in the NAcS of ISO rats. The aversive effects of this compound stimulus may negate the rewarding effects in isolates.

Summary The effect of the dopamine agonist, bromocriptine, and the dopamine antagonist, metoclopramide, on glucose tolerance was examined in maturity onset diabetics and normal subjects. After bromocriptine there was a lowered fasting blood glucose and improved glucose tolerance in the diabetics. The controls showed an initial improvement in glucose tolerance. A reduction in insulin levels and a marked fall in plasma prolactin was observed in all subjects. Growth hormone concentrations were low and unaffected in the diabetics, and there was an inconsistent rise in the normals. After metoclopramide there was some impairment in glucose tolerance in the normal subjects, but this was not significant in the diabetics. There was also a marked prolactin release in all subjects, but no significant effect on insulin or growth hormone. It is concluded that bromocriptine lowers the blood glucose and improves glucose tolerance in maturity onset diabetics. This action may be the result of the lowered prolactin which occurred without a concomitant rise in growth hormone.

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This paper reports the determination of absorbed dose to bone marrow in the treatment of polycythaemia by 32P, based on the measurement of activities in bone and marrow biopsies taken at various times from 1 to 27 days after injection of the radionuclide. Activities were measured in the cortex, trabeculation and marrow of biopsies taken from the iliac crest, and slso in sternal marrow. The biological half-life of 32P in marrow from the iliac crest was found to be nine days; that derived for sternal marrow was lower, but the difference was not statistically significant; the value for trabecular bone was 27 days. The biological half life for 32P in the body, as measured by whole-body counting, was 39 days. Calculations of the dose-rate to trabecular marrow have been made by a method based on that of Whitwell and Spiers (1971), but modified to allow for the presence of32P in the marrow as well as in trabecular bone. The dose-rates follow a single exponetial decay with a half-life of 6.7 days. The intergrated dose including that during the first day is 24 rad per mCi injected.

Summary: A rapid, sensitive, and precise method for measuring the plasma digoxin concentration has been developed with the radioimmunoassav technique. Seventy patients receiving digoxin were shown to have plasma digoxin concentrations between 0.4 and 5 ng./ml. Preliminary studies show that though there is a positive correlation between total daily dose and the plasma digoxin concentration, the relationship is not close, and a relatively wide range of plasma digoxin concentrations appear to be consistent with effective digitalization.