The chemiluminescence response and bactericidal activity of polymorphonuclear neutrophils from newborns and their mothers

Chemiluminescence (CL) was measured in the polymorphonuclear neutrophils (PMN) of 18 normal term infants, their mothers, and controls during phagocytosis of opsonized zymosan particles. Chemiluminescence was significantly lower in the PMN of newborns in comparison with the PMN of their mothers and of the controls. Depressed bactericidal activity was demonstrated in newborn PMN, in comparison with the activity of the PMN of their mothers and controls, when challenged with Escherichia coli at large bacteria-PMN ratios. Uptake of radio-labeled bacteria by PMN was identical in newborns, mothers, and controls, which indicates that reduced CL was not a result of impaired ingestion. Therefore, PMN of normal term infants have both depressed oxidative metabolic responsiveness as measured by CL and depressed bactericidal capacity.

Chronic effects of methadone on a line tilt generalization gradient in the pigeon

Using an adjusting interval schedule, pigeons were trained to key peck at a relatively constant rate during 45 degrees line tilt presentations and at an extremely low rate in the presence of 0 degrees and 90 degrees line angles. Subsequently, the birds received intramuscular injections of methadone hydrochloride every 8 hr in doses beginning at 3 mg/kg/day and increasing progressively to 90 mg/kg/day. Stimulus generalization tests were run on the first day and on the last day a given dose was administered to assess the development of tolerance. Although chronic methadone treatment was associated with an overall decrement in key peck rate, the gradients of line tilt generalization were indistinguishable from saline control gradients at doses as high as 90 mg/kg/day. Though the birds exhibited gross behavioral incoordination, visual stimulus control appeared unaffected.

d-amphetamine and fixed-interval performance: effects of operant history

Sixteen rats were initially exposed for 50 sessions to either a fixed-ratio 40 or an interresponse-time-greater-than-11-second food reinforcement schedule, then shifted to a fixed-interval 15-second food reinforcement schedule. Animals with fixed-ratio 40 histories lever pressed at much higher rates under the fixed-interval schedule than did animals with inter-response-time-greater-than-11-second histories. This difference persisted across 93 sessions of fixed-interval exposure. The effects of d=amphetamine were assessed after 15 and 59 sessions of fixed-interval exposure. On both occasions, the low-rate responding of animals with interresponse-time-greater-than-11-second histories was typically increased by all doses of the drug, while the high-rate responding of animals with fixed-ratio 40 histories was typically decreased by all doses of the drug. These results suggest that control response rate under the fixed-interval schedule, which may be affected by a history of responding under another schedule, is the primary determinant of the relative effects of d-amphetamine.

Characteristics of a somatostatin-binding protein

The concentrations of a somatostatin-binding protein, found in the cytosol of a number of rat tissues, are similar in both sexes, and hypophysectomy has little or no effect on the level of binding protein in tissue extracts. On the other hand, streptozotocin-induced diabetes mellitus causes a modest decrease. The somatostatin-binding proteins obtained from extracts of several rat tissues are not only similar in molecular weight but also exhibit a similar isoelectric point and electrophoretic mobility. Agents that block thiol groups or prevent the formation of disulfide bridges markedly decrease the binding of somatostatin to the cytoplasmic protein. Studies using thiol reagents and gel filtration suggest that free thiol groups in somatostatin-binding protein are important for the binding of somatostatin.

Ketamine self-administration by the rhesus monkey

Intravenously administered ketamine served as a reinforcer of self-administration behavior in rhesus monkeys during daily 2-hour sessions. When the dose of ketamine was varied over a wide range at fixed-ratio schedules of reinforcement of 1, 8 and 64, the response rate was an inverted U-shaped function of the dose. Maximal response rates occurred at progressively higher doses as the fixed-ratio size was increased; drug intake per session was positively related to the dose. When the ketamine dose was held constant and the fixed-ratio was increased in a geometric series, the response rate increased as the fixed-ratio was increased to FR 128 or FR 256; additional increases in fixed-ratio size produced abrupt decreases in response rates. Since the response rate increased linearly as the fixed-ratio was increased geometrically, drug intake was a decreasing function of the response requirement. With respect to magnitude of reinforcement and fixed-ratio response requirement, the data show that ketamine maintains self-administration behavior in a manner similar to that of a number of other drugs and conventional reinforcers.

Suppression of ethanol-reinforced lever pressing by delaying food availability

When food was initially available to rats under a fixed-interval 26-second schedule and each liquid-reinforced lever press delayed food availability 8 seconds, suppression of liquid-reinforced lever pressing and liquid consumption occurred when the liquid presented was 4, 8, 16, 32, and 0% ethanol. Suppression did not occur in yoked-control animals, which received food coincidentally with experimental animals but were not directly exposed to the delay dependency. After exposure to the food schedule, each ethanol solution served as a reinforcer in the absence of food presentation. Delaying food availability for increasingly long periods (8 to 2048 seconds) suppressed ethanol-reinforced lever pressing and consumption relative to baseline levels, with the maximum decrease being below the level maintained in the absence of food. However, degree of suppression did not increase monotonically with delay length. Liquid-reinforced performance of yoked-control animals indicated that suppression did not result from changes in the sequencing of food presentation alone.

Attenuation of ethanol intake by contingent punishment of food-maintained responding

Two food-deprived rats responded under a concurrent fixed-ratio 12 (food) fixed-ratio 1 (8% ethanol) reinforcement schedule in which a tone occurred during every second or every fourth interpellet interval. When ethanol-maintained lever presses during the presence of the tone shifted the food schedule to one in which electric shock punishment occurred, ethanol-maintained responding consistently decreased. The decrease in the frequency of ethanol-maintained responding varied directly with shock voltage from 25 to 100 V, and occurred during intervals with the tone present and absent. These results indicate that ethanol intake may be attenuated by contingent changes in a concurrent food schedule.

Effects of feeding regimen on ethanol intake by guinea pigs

During daily two-hr sessions, guinea pigs licked a drinking tube filled with either 0 (tap water), 2,4 or 8% (v/v) ethanol solution under three feeding regimens. Consumption of each solution was highest when sufficient food to maintain subjects at 90% of free-feeding weight was provided during sessions, lower when the same food ration was provided after sessions, and lowest when ad lib access to food was provided within and between sessions. However, this decrease in consumption across feeding regimens was inversely related to ethanol concentration. Under all feeding regimens, volume of solution consumed decreased with increasing ethanol concentration while milligrams ethanol consumed increased with ethanol concentration. These results are similar in some respects to previous findings with rats and monkeys, suggesting that further studies of oral ethanol self-administration by guinea pigs may be merited.

Effects of d-amphetamine and chlordiazepoxide on positive conditioned suppression

Six rats lever-pressed under a variable-interval 80-sec food reinforcement schedule. After responding had stabilized, an 8-sec tone terminating with food delivery was superimposed on the variable-interval schedule on the average once every five minutes without regard to the animal's behavior. This positive conditioned suppression procedure consistently reduced responding during the pre-food stimulus (tone). Neither d-amphetamine (0.5, 1.0, 2.0 mg/kg) nor chlordiazepoxide (7.5, 15, 30 mg/kg) significantly affected the relative suppression produced by the tone. Instead, both drugs produced generally non-selective effects, similarly affecting response rate in the presence and absence of the tone.

Properties of soluble somatostatin-binding protein

A soluble somatostatin-binding protein was detected in the cytosol fractions of various rat, human and bovine tissues. Maximum binding occurred at pH8.0-8.5 and was Ca(2+)-dependent. The specific binding of somatostatin per 10mug of cytosol protein from 12 rat tissues ranged between 36 and 15%, and 3% for peripheral blood cells. There was also substantial binding in cytosol from human anterior pituitary and liver, and bovine anterior pituitary. The specific binding in rat and human plasma in the presence of EDTA was only 1%. Gel filtration suggested a molecular weight of approx. 80000 for the somatostatin-binding protein from several sources. Exposure of the binding protein to trypsin eliminates somatostatin-binding activity but ribonuclease and deoxyribonuclease have no effect. The binding protein is thermolabile, ethanol-precipitable, and not completely specific for somatostatin. Bound (125)I-labelled [Tyr(1)]somatostatin is not easily displaced by excess of unlabelled somatostatin. The effects of dithiothreitol and mercaptoethanol on the binding of (125)I-labelled [Tyr(1)]somatostatin to the binding protein suggests that binding involves two sequential steps, first loose binding, then disulphide linkage. Since semipurified somatostatin-binding protein causes a dose-related inhibition of the binding of (125)I-labelled [Tyr(1)]somatostatin in radioimmunoassays for somatostatin, estimates of somatostatin content of tissue extracts by radioimmunoassay in some cases may be spuriously high. It is not yet clear whether the binding protein is a true cytosol protein or an easily solubilized membrane protein.

The effects of d-amphetamine on the automaintained key pecking of pigeons

Three food-deprived pigeons were initially exposed to an automaintenance procedure in which 8-s response key illuminations were followed by food delivery without regard to the subject's behavior. The percentage of occasions on which key illumination was followed by food delivery was then successively reduced from 100 to 50, 25, 10, and 2.5%. Despite the lack of a programmed contingency between key pecking and food delivery or key illumination, key pecking occurred under all automaintenance conditions. Mean responses per 8-s key illumination during non-drug sessions varied from over 15 to less than one, with the 100 and 50% pairing conditions engendering the highest rates and the 2.5% pairing condition the lowest. Under all automaintenance conditions, d-amphetamine in does of 0.5, 1, and 2 mg/kg decreased responding in a dose-dependent fashion. Rate-dependent effects were not evident despite the appreciable differences in mean response rates engendered by the various conditions.

Effects of delaying food availability contingent on ethanol-maintained lever pressing

The effects of delaying food availability 8 s contingent on every, every second, and every fourth lever press maintained by 4,8, and 16% (v/v) ethanol solutions were examined when food was initially available to rats on a fixed-interval 26-s schedule. The delay contingency decreased ethanol-maintained responding at all ethanol concentrations, with the degree of decrease inversely related to the intermittency of the delay schedule and to the ethanol concentration. Such decreases were not evident in the performance of yoked-control animals which received food coincidentally with experimental animals. Temporal changes in food presentation alone therefore could not account for the decreases produced by the delay contingency.

Prevalence of diabetes in Michigan school-age children

A mail survey of Michigan school districts elicited information of 2,816 children and adolescents with diabetes, a rate of 1.6 per 1,000. Rates were higher for females than males and for whites than non-whites and increased with advancing age. A total of 15.5 per cent were reported to be not receiving insulin by injection.

Uptake of 3H-uridine into brain and incorporation into brain RNA of rats exposed to various training tasks - a biochemical analysis

Operant schedules were used to isolate component parts of a training task and rates of incorporation of 3H-uridine into the brain and brain RNA were determined. Rats that developed a discrimination in responding to a visual stimulus absorbed more radioactivity into the brain and incorporated a higher percentage of this radioactivity into total and cytoplasmic RNA than littermates exposed to the visual stimulus only. Of the component parts of the training task, the discrimination accounted for the greatest increase in absorption of radioactivity and incorporation of it into RNA. The schedule change had the second largest effect and the stimulus change the least.

Effects of chlorpromazine and pentobarbital on pattern and number of responses in extinction

In a series of experiments rats were trained and subsequently extinguished under different conditions of drug administration. High doses of chlorpromazine (5 mg/kg) or pentobarbital (20 mg/kg) were administered during the first extinction session and the dose was progressively reduced to zero over 10 successive sessions. Extinction was continued until all Ss had consistent near zero responding. When compared to saline control, chlorpromazine had no effect on total extinction responding, while pentobarbital significantly reduced total extinction responding. Ss receiving both drugs had erratic runs of responding in extinction, whereas Ss receiving saline showed a normal extinction pattern. Ss receiving pentobarbital during both training and extinction had more total extinction responding than Ss receiving only pentobarbital in extinction.

Responding maintained by the opportunity to attack during an interval food reinforcement schedule

Pigeons responded in a two-key situation. Responses on the right key (food key) were reinforced with food presentation on a response-initiated fixed-interval schedule, (i.e., first response after a fixed period of time was reinforced); responses on the left key (target key) were reinforced on a fixed-ratio schedule (i.e., every nth response was reinforced) with the presentation of a target bird that could be attacked. When the interval value of the food reinforcement schedule was varied from 1 min to 5 min, both the rate of attack responding on the target bird and the rate of responding on the target key were a function of the interval value. Responding on the target key was not maintained by the stimulus change associated with target availability, and was successively extinguished and reconditioned by removing and returning the target bird to the restraining box. When food was delivered independently of behavior, responding on the target key either remained unchanged or decreased, but was not eliminated. Responding on the target key was not maintained in the absence of an intermittent schedule of food presentation.