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S Armstrong

Publications and source records attributed to S Armstrong.

At least 127 records · Page 7Linked to original sources
PubMed1983

Free-running activity rhythms in the rat: entrainment by melatonin.

The pineal gland hormone melatonin may play a role in synchronization of rat circadian rhythms. Free-running activity rhythms of the rat were entrained by a daily melatonin injection, with entrainment occurring when the onset of activity coincided with the time of daily injections. When injections were stopped, activity rhythms became free-running again. Thus in pharmacological experiments, the time of day of melatonin administration is crucial.

Animals↗
PubMed1983

Influence of 2-deoxy-D-glucose on feeding in the rat at different times of the light-dark cycle.

Two concentrations of 2-deoxyglucose (2-DG) were injected into adult male Long-Evans rats at four times during the 12:12 light/dark cycle. At low concentrations (300 mg/kg) in the first 3 h of a 6-h test period, 2-DG significantly increased feeding (268%) in the early part of the light period (EL) when compared to uninjected and saline-treated controls. In the late light (LL), 2-DG increased feeding by 48% but this was not statistically significant. For the high-concentration groups (750 mg/kg), 2-DG increased feeding by 240% in the EL, 117% in the LL, 50% in the early dark (ED) and 45% in the late dark (LD). As there was no significant interaction, it was concluded that 2-DG facilities feeding at all times of the day. In the second 3 h of the recorded 6 h, 2-DG decreased feeding by 37-45% in the ED and middle dark (MD) when compared to controls, although the suppression was significant only for the low concentration of 2-DG. There was some support from data on water intake and latencies to eat and drink for the view that 2-DG-induced feeding was not secondary to thirst stimulated by hypertonic injection fluids. It is concluded that 2-DG injection facilitates feeding for a few hours but the net effect on food intake may be reduced in the light, and even nullified in the dark, by a subsequent reduction of intake in rats with free access to food.

Animals↗
PubMed1982

Evidence for a separate meal-associated oscillator in the rat.

Three experiments were conducted to explore the relationship between food availability and the wheel running activity rhythms of intact rats. In two experiments re-entrainment when meal times were changed was studied. The rats showed an increase in activity immediately prior to a regular feeding time and this increase was more rapid when rats had been fed at that time in an earlier condition. Some evidence of transients at a former meal time was observed when the meal time was shifted to later in the day, but not when the meal time was shifted to earlier in the day. This led to the hypothesis that ad lib feeding masks rather than abolishes meal-entrained activity. In a third experiment, therefore, rats were entrained to a daily meal under a light-dark (LD) cycle, then placed in constant dark (DD) on ad lib food with occasional periods of deprivation. A burst of activity associated with the former meal time occurred during the deprivation period, but not during ad lib periods; it returned during subsequent deprivation. It is concluded that meal feeding entrains a separate oscillator with a period different from the oscillator entrained by the LD cycle.

Animals↗
PubMed1981

The media as an approach to adolescent health education.

A series of eight 60-second dialogues was cooperatively produced by the Tacoma-Pierce County Health Department's Adolescent Clinic and KTAC Radio, Tacoma, Washington. The format was one in which the radio announcer made a statement concerning adolescent health, followed by an adolescent's asking a specific health question, a response being made by a health professional, and the announcer's concluding by giving a local resource and phone number. Included in this series were questions about weight reduction, scoliosis, headaches, hypertension, sexually transmitted diseases, temper and anger, stress, and fatigue. The dialogues were aired ten times a day at times appropriate for the adolescent listener. In addition to acquainting the adolescent with clinic and community services, this series gave answers to many developmental questions that may influence the adolescent's behavior and self-concept.

Adolescent Medicine↗
PubMed1981

Brief psychodynamic psychotherapy: interrater agreement and reliability of individually specified outcomes.

We tested Malan's method of constructing outcome criteria in brief dynamic psychotherapy by positing a core neurotic problem, psychodynamic outcome criteria, and psychodynamically oriented target criteria for 41 neurotic outpatients receiving either psychotherapy or behavioral therapy. We found that trained raters could assess psychodynamic problems and outcomes with high interrater reliability and agreement. Using these measures with behavioral therapy as well as psychodynamic therapy patients, we found that the psychodynamic ratings could be extended to patients not treated psychodynamically. Thus, we feel individualized psychodynamic ratings can be used to assess treatment effects on a reliable psychodynamic basis, and that individualized ratings can be extended to studies which contrast specific psychodynamic outcomes to those of other treatments.

Adult↗
PubMed1981

Effects of restricted food and water regimes on the estrous cycle of the rat.

The possibility that daily food and water presentation is a more potent synchronizer to the estrual rhythm of the female rat than the light-dark cycle was investigated by presenting food and water ad libitum only during the dark period or only during the light period of an LD 12:12. It was found that the daily feeding and drinking regimes did not synchronize the estrous cycle, but only disrupted the synchrony between the LD cycle and the estrous cycle. Because there was no significant difference between body weights of the groups, results cannot be interpreted in terms of under-nourishment effects on hormone synthesis, but rather in terms of the temporal characteristics of food and water intake.

Animals↗
PubMed1980

Persistence of rat nocturnal feeding and drinking during diurnal presentation of palatable diet.

Male laboratory rats were fed a highly palatable diet during the light phase of a 12:12 LD cycle. Nocturnality of feeding was reduced from approximately 77% of the total daily intake to 56%. Increase in diurnal feeding was attributable to the ingestion of a large meal at the beginning of the L phase. Reduction of nocturnal feeding was attributable to decreased ingestion in the first 3 hr of the D phase. Outside these times the daily feeding pattern was unmodified. These findings do not represent a reversal of the feeding rhythm as previously reported, but a modification which is not consistent with interpretation as a phase-shift. Throughout the testing period total daily food intake remained unchanged and body weight was defended despite the increase in calories ingested. Daily drinking patterns and total daily water intake were not significantly altered by the experimental manipulation.

Animals↗
PubMed1980

Food and water deprivation: changes in rat feeding, drinking, activity and body weight.

Groups of male rats totally food deprived for periods up to 96 hr, water ad lib do not totally regain body weight lost through deprivation. Degree of body weight defence was estimated by fitting statistically a curve to the predeprivation baseline data and extrapolating the curve over the deprivation and postdeprivation period. From group data, body weight is not fully defended. However, marked individual differences in degree of body weight defence were noted. During food deprivation the daily drinking cycle persists for approximately 48 hr, then a reduction in nocturnal drinking appears. General activity increases but only in the light period. After food restitution, the main hyperphagia is confined to the first post-deprivation day. Additional, subtle long term effects of overeating in the light period are also found. In contrast to food deprived groups, water deprived groups accurately defend body weight. During water deprivation daily food intakes decrease immediately whereas nocturnal activity decreases after approximately 72 hr of deprivation has elapsed. After the termination of water deprivation the immediate response is gross hyperdipsia, but again subtle long term effects are apparent. Total daily food intake increases for many days but the increase is not confined to either light or dark periods. Water intake is similarly affected. These results are evaluated in relation to the notion of a body weight set-point regulating feeding behavior. Some limitations on the value of the findings in terms of species differences and lack of ecological validity are also discussed.

Animals↗
PubMed1980

A chronometric approach to the study of feeding behavior.

In many mammalian genera, the stimulus to feed is intimately associated with circadian rhythms. This stimulus arises from within the brain from biological time-keeping systems. Such a chronometric approach to feeding behavior follows from a consideration of the terrestrial mammal's space-time pattern within the ecological niche. The ecological niche is a division of time as well as space. The restriction of certain behaviors to certain times of day and the concomitant evolution of nocturnality or diurnality represent strong advantages for survival in the wild. Experimental data, primarily from studies on the rat, in support of the chronometric approach, include: the reinstatement of cyclic feeding patterns after food deprivation; the continuation of circadian pattern of wheel running and nocturnal drinking during food deprivation; consideration of the ontogeny of the feeding pattern; the phenomenon of anticipatory appetite--the experimental demonstration that time of day can act as a conditioned stimulus for feeding; the evaluation of rhythms in digestion, absorption and assimilatory biochemical processes; the realization that many of these rhythms are not simply a consequence of the presence of food in the gut; the realization that the brain exerts considerable control over the peripheral rhythmic nutritional processes via ANS and endocrinological systems; and the fact that within the brain the SCN and structures well known to be involved in nutritional regulation, such as the VMH, LHA and monoamine systems, may all be involved in the circadian pattern of feeding. Further, the function of these neurological structures may be understood better by consideration of data from temporal changes in feeding patterns.

Amino Acids↗
PubMed1980

Dual focus in brief psychodynamic psychotherapy.

The therapist needs to choose well the focus of treatment in brief psychodynamic psychotherapy, lest the therapy become fragmented. The therapeutic focus is crucial to the treatment of very impaired patients, in whom many experiences of themselves or others are compartmentalized or split off. Without a focus as a therapeutic tool to reintergrate these experiences, the patient becomes confused by interpretations directed at multiple, segregated parts of him or herself. When the therapist has not established a treatment focus, the therapist also becomes confused by the patient's multiple experiences of self and others. A case example illustrates the therapy of a patient who required dual foci arranged sequentially, in which the therapist treated three aspects of the patient's self-image as a primary focus, and the patient's grief over two stillborn children as a second focus. The patient could not grieve until the primary focus helped repair the breech in the patient's self-image.

Adult↗