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Results for “interaction effect”

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At least 37 records · Page 2Linked to original sources
PubMed1975

Multiple myeloma in a patient with sickel cell anemia. Interacting effects on blood viscosity.

Described here is a case of multiple myeloma in a patient with sickle cell anemia. Viscometric studies were made by comparing the patient's whole blood, plasma and washed red blood cells with those of a normal control subject and a patient with sickle cell anemia. Results showed that the increased viscosity of the patient's whole blood as compared with that of the control patient with sickle cell anemia was mainly due to erythrocytic interaction with the circulating abnormal immunoglobulin. It is postulated that the increased frequency of vaso-occlusive crisis that occurred in our patient in the months before the diagnosis and treatment of multiple myeloma, was due to this cell-protein interaction with the resulting enhancement of whole blood viscosity and the sickling phenomena.

Adult↗
PubMed1976

Interaction effects of d-amphetamine treatment and ambient temperature on rat's food intake.

The "thermoregulatory theory of hunger" posits that rats placed in a cold environment should increase the amount of food intake, while rats placed in a hot environment should decrease their food intake. d-Amphetamine causes hyperthermia among rats kept at warm ambient temperature, and results in hypothermia among animals kept in a cold environment. d-Amphetamine-caused-hyperthermia should therefore result in decreased eating behavior, and d-amphetamine-caused hypothermia should result in increased eating behavior. One must take into account the fact that d-amphetamine is an anorexic drug. The interaction between (a) ambient temperature, (b) body temperature and (c) food intake were tested on groups of rats injected with various doses of d-amphetamine (1.5-15 mg/kg) and placed in ambient temperatures ranging from 4-37 degrees C. No increase in food intake was revealed under any dosage or temperature condition. The decrease in food intake found with d-amphetamine treated animals could not be explained in the "thermoregulatory theory of hunger". Our data indicate that d-amphetamine anorexic effects and thermal effects are mediated by different mechanisms.

Animals↗
PubMed1979

Should the concept of the recommended dietary allowance be altered to incorporate interactive effects of ubiquitous pollutants?

Using ascorbic acid as a model, this paper proposes that the concept of the RDA should be broadened to take into account the effects of ubiquitous pollutants on human health, a factor presently not incorporated in RDA derivations. It is now widely accepted that ascorbic acid nutritional status markedly affects the toxicity and/or carcinogenicity of greater than 50 pollutants, many of which are ubiquitous in the air, water, and food environments. At the present time, the data do not warrant changing the ascorbic acid RDA in light of the knowledge of pollutant interactions.

Animals↗
PubMed1979

Cooperative lipid-protein interaction. Effect of pH and ionic strength on polymyxin binding to phosphatidic acid membranes.

The binding of polymyxin-B to charged dipalmitoyl phosphatidic acid membranes has been studied as function of the external pH and of the ionic strength of the buffer solution. The phase transition curves were obtained by measuring the fluorescence depolarization of diphenyl hexatriene incorporated into the membrane with temperature. The molecular process of polymyxin binding was elucidated: 1. At an ionic strength of I greater than or equal to 0.1 mol/l a three step phase transition curve is found. A high-temperature step corresponds to the non-bound lipid. A lowered phase transition concerns to protein-bound lipid domains. This again is splitted into two steps. An inner core of the domain is characterized by a lipid-protein complex which is stabilized through hydrophobic and electrostatic interactions between polymyxin and the charged lipid. This core is surrounded by an outer belt of only hydrophobically bound molecules. This part shows a lower phase transition temperature than the inner core. 2. The binding curves of polymyxin to phosphatidic acid membranes depend strongly on the ionic strength of the water phase. The cooperativity of the binding process increases with increasing ionic strength and reaches a constant value at I greater than 0.2 mol/l. The maximum fraction of bound lipid decreases with increasing ionic strength. 3. The pH of the water phase strongly influences the cooperative binding process. At pH 6 a loss of cooperativity is observed at low ionic strength. Increasing the ion concentration to I = 0.3 mol/l recuperates the cooperativity of the binding process. At pH 3.0 no cooperative binding is obtained even at high ionic strength.

Hydrogen-Ion Concentration↗
PubMed1978

Perinatal malnutrition and early handling: interactive effects on the development of the pituitary-adrenal system.

The preweaning development of the pituitary-adrenal system was investigated in perinatally malnourished rodents. Malnourished pups that were routinely handled displayed an earlier plasma corticosterone stress response to electric shock and an accelerated development of feedback inhibition of the stress response by exogenously elevated steroid levels. Although malnourished pups displayed elevated basal corticosterone levels compared to well-fed controls, the post-stress levels were also higher in these malnourished young. Thus, the corticosterone response to stress was not impaired in malnourished pups. The influence of the early handling of malnourished young on pituitary-adrenal activity was also studied. Whereas the accelerated development of the stress response and the elevated post-shock levels were not the result of early handling, the elevated basal corticosterone levels displayed by handled malnourished pups were not present in nonhandled malnourished pups. Thus, the early non-nutritional environment interacts with malnutrition to alter the development of the pituitary-adrenal system.

Animals↗
PubMed1976

The administration of metoclopramide with atropine. A drug interaction effect on the gastro-oesophageal sphincter in man.

The effects of intravenous atropine 0-6 mg alone, metoclopramide (Maxolon) 10mg alone and atropine 0-6 mg and metoclopramide 10 mg in combination, on the lower oesophageal sphincter (LOS) were studied in three groups of normal human volunteers. Atropine decreased the LOS pressure by an average of 8 cm H2O (P less than 0-001), whereas metoclopramide increased the LOS pressure by a mean of 29 cmH2O compared to basal values (P less than 0-001). In contrast, no change in sphincter tone was noted following injection of atropine-metaclopramide mixture. These findings are relevant to the pre-operative preparation of patients presenting for emergency anaesthesia, since gasgro-oesophageal reflux and pulmonary aspiration of acid gastric content continues to be a significant cause of morbidity and mortality.

Adolescent↗
PubMed1977

Interactive effects of parity and pup stress on the maternal behavior of Rattus norvegicus.

Litters of primiparous and multiparous rat mothers received 0,2, or 5 min of cold stress for the 1st 5 days postpartum. Primiparae showed increasing maternal responsiveness over the treatment period. Multiparae were initially maternally responsive to moderate stress cues from pups, but habituated to them over days. From Days 6 to 20, when pups were not stressed, lactation behavior of stressed groups declined in primiparous mothers but not in multiparous mothers.

Animals↗
PubMed1978

Interactive effects of parity and early pup stress on the open field behavior of laboratory rats.

Pups of primiparous and multiparous Sprague Dawley rats received 0-, 2-, or 5-min cold stress on Days 2-6 postpartun. Stressed offspring of primiparous mothers had shorter latencies to move in an open field than did control offspring of primiparous mothers. However, stressed offspring of multiparous mothers had longer latencies than did the controls. The results suggest differences in maternal responsiveness immediately following return of stressed pups to the nest.

Animals↗
PubMed1976

Interaction effects among cortical bone, cancellous bone, and periodontal membrane of natural teeth and implants.

Following the initial successes of Goldberg and Gershkoff (Dental Digest, 5, 11, 1947) with the placement of subperiosteal implants, interest in all types of implants emerged. As an aid to the evaluation of various designs and materials without resorting to clinical testing, finite element analyses are being conducted by a number of researchers to determine the stress system induced in bone. The present study investigates the effects of variation in the thicknesses of the periodontal membrane and cortical bone and of the model boundary on the stresses developed around a natural tooth or a tooth-shaped implant. The results show that strong effects due to the variation in these parameters can be expected. As a consequence, the problem of the analysis of any single implant must consider additional factors. These can influence overall implant design and may eventually help to explain what could appear as anomalies in clinical test results.

Alveolar Process↗
PubMed1976

Interactive effects of brain catecholamines and variations in sexual and non-sexual arousal on copulatory behavior of male rats.

In pargyline pretreated male rats, an intraventricular 6-hydroxydopamine procedure which resulted in subtotal brain catecholamine (CA) depletion produced a mild defict in copulatory behavior followed by rapid recovery. Challenges employed to study the behavioral capacities of these 'recovered' animals revealed: (1) a heightened sensitivity to acute treatment with the CA synthesis inhibitor alpha-methyl tyrosine (AMT) as reflected in a reinstatement and exaggeration of the original copulation deficit; (2) a greater dependence on the sexual eliciting properties of the female, since abolishing her soliciting behavior also reinstated and exaggerated the sexual dysfunction; and (3) a pattern of behavioral impairment indicating increased difficulty in both initiating sexual activity and maintaining copulatory performance. Furthermore, in males not copulating after 6-OHDA/AMT treatment, copulation could easily be induced by the simple application of a non-specific activating stimulus. On the basis of these data and parallel findings reported for other behaviors, we have concluded that: (1) both the initiation and maintenance of copulatory behavior in the male rat is the part dependent on normal functioning in one or more of the brain CA-containing systems; and (2) this copulatory deficit is symptomatic of a broader functional impairment reflecting reduced behavioral responsiveness to stimuli that normally elict appetitive or approach responses but not to stimuli requiring more automatic, inhibitory responses.

Animals↗
PubMed1979

Interaction effects of extraversion and neuroticism on detection thresholds.

Detection thresholds for electrocutaneous stimulation were measured in young male subjects by two different methods - a method of limits and a forced-choice method - the latter assumed to be less influenced by decision processes. Relations between the threshold measures and scores in the EPI extraversion (E) and neuroticism (N) scales were studied. High N-low E ("unstable introvert") subjects had the lowest thresholds. The result is in line with the predictions made on the basis of Eysenck's personality theory.

Adult↗
PubMed1975

Interactive effects of training condition and septal lesions on perseverative responding in the rat.

Rats that had received septal lesions either prior to acquisition of a position habit (Group SAR) or immediately after position habit acquisition (Group SR) were tested on two reversals of the task. Compared with control-operated rats, both groups of rats with septal lesions exhibited position-habit reversal deficits. The two groups with septal lesions could not be distinguished in terms of the total number of errors made during reversal learning, but could be distinguished on the basis of the type of error committed. Compared with Group SR, Group SAR made significantly more perservative errors on the first reversal and significantly fewer perserverative errors on the second reversal. Group SR made significantly more nonperservative errors than Group SAR on both reversals.

Animals↗