Replication as a determinant of the intestinal response to rotavirus

Mucosal antibody induction by otherwise identical replication-competent and replication-incompetent rhesus monkey rotaviruses was compared. Although psoralen-inactivated virus induced diarrhea, the magnitude of the intestinal antibody response was severely attenuated compared with that of replicating rotavirus, as determined by assay of mucosal antibody-secreting cells. Rotavirus that was neutralized by monoclonal antibodies (anti-VP4 and -VP7) prior to inoculation was similarly ineffective at induction of specific antibodies in intestinal secretions. In contrast to genetically inactivated virus, antibody-neutralized virus did not induce diarrhea. In this murine model, viral replication is an important determinant of antibody induction. The diarrhea response is blocked by neutralizing antibodies, but the mechanism of action is not exclusively the inhibition of viral replication.     

Type of punishment as a determinant of resistance to deviation.

Compared the effectiveness of an aversive stimulus, withholding of resources, withdrawal of love, and reasoning, when used alone and when combined with praise, in a standard laboratory punishment paradigm using 120 1st- and 2nd-grade boys and girls as Ss. Resistance to deviation and stability of resistance to deviation were used as the measures of punishment effectiveness. Sex of child, use of praise, and type of punisher were combined in a 2 * 2 * 5 factorial design, with a female as the punitive agent. An aversive stimulus appeared to produce more suppression of deviant behavior, but the effect was not significant for all response measures. The stability of the deviant response pattern varied for each punisher, but the most stable response pattern resulted from the use of an aversive stimulus. Neither use of praise nor sex of child significantly influenced punisher effectiveness. Results are discussed within the framework of anxiety arousal and information content of the punishers, and the practice of grouping various punishers under the categories of sensitization and induction measures is considered. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selenium intake as a modulator of responsiveness to oxidative stress

A deficiency in important components of the endogenous antioxidative defense system (AODS) against the production of reactive oxygen species, including free radicals, results in the accumulation of oxidative damage, inducing oxidative stress. A dietary deficiency in selenium (Se), an important part of AODS, can increase the sensitivity of a living system to oxidative stress. We investigated the effects of Se supplementation, in the form of Se-enriched yeast, on the AODS resistance of red blood cells (RBC) to experimentally induced oxidative stress. We analyzed the alterations in main components of the AODS, such as the amount of reduced (GSH) oxidized glutathione (GSSG), Se-dependent glutathione peroxidase (GSH-Px), Se content, catalase (CAT), and thiobarbituric acid reactive substances (TBARS), in RBC of male Wistar rats exposed to gamma rays and supplemented with Se-enriched yeast (SeY) in drinking water. The results suggested that the increased Se level generally exhibited a protective effect against whole body irradiation, reducing the expenditure of the AODS components in defense. These reductions differed depending on the time observed and the parameter investigated but, generally, SeY supplementation induced a faster restoration of the AODS after this kind of oxidative stress.     

When pleasure begets pleasure: Recipient responsiveness as a determinant of physical pleasuring between heterosexual dating couples and strangers.

Contrary to the notion that positive verbal responses reinforce behavior, research on physical pleasuring has demonstrated that positive verbal responsiveness from a recipient of pleasurable vibrations inhibits, rather than facilitates, heterosexual pleasuring. The present research examined the role of recipient responsiveness in interpersonal pleasuring through comparison of established dating couples with ad hoc pairs. Using the pleasure paradigm developed by the 1st author et al (1976), 160 undergraduate couples—either established dates or ad hoc pairs—delivered intensity-graded pleasurable vibrations to the buttocks and thighs of a recipient. It was predicted that among dating couples, intimacy would be perceived as appropriate; hence, responsiveness would facilitate rather than inhibit pleasuring. In the case of strangers, however, it was expected that intimacy would be perceived as inappropriate; hence, responsiveness would not facilitate pleasuring. Results support the predictions. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Female gender as a determinant of cough threshold to inhaled capsaicin

Chronic, nonproductive cough and cough associated with the use of angiotensin converting enzyme inhibitors, are more frequently observed in females as compared to males. To examine the influence of sex, age, height, weight and pulmonary function on airway cough sensitivity, cough threshold to inhaled capsaicin, an index of the airway cough sensitivity, was measured in 160 nonsmoking, nonatopic healthy subjects. Forty young males (aged 24 +/- 2 yrs) 40 young females (aged 22 +/- 2 yrs) 40 middle-aged males (aged 48 +/- 5 yrs) and 40 middle-aged females (aged 50 +/- 7 yrs) were studied. The cough threshold was defined as the lowest concentration of inhaled capsaicin causing five or more coughs. The cough threshold was 3-5 fold lower in females than in males both in young (p<0.001) and middle-aged (p<0.005) subjects. Cough threshold was weakly but significantly correlated to height, weight, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) when all subjects were considered together but not when each group was considered separately. Multiple regression analysis revealed that sex difference was the significant predictive factor for the cough threshold in either age group. These results confirm that cough sensitivity is heightened in females and suggest that influence of height and pulmonary function on the cough threshold may have resulted from sex difference.     

Temporal encoding as a determinant of overshadowing

OBJECTIVE: To examine changes over time in consonant feature production by children with profound hearing impairments who used either the Nucleus multichannel cochlear implant or the multichannel vibrotactile aid, Tactaid 7. DESIGN: Imitative consonant productions of children with prelingual deafness were elicited and transcribed at two intervals: 1) before receiving their respective devices (predevice interval), and 2) after an average of 1.5 yr of device use (postdevice interval). The consonant productions were analyzed in terms of the percentage of consonant features (manner, place, and voicing) produced by the child that matched the features of the examiner's target. The percentage of features produced correctly was then averaged across repetitions, vowel environments, and participants within each group. RESULTS: At the predevice interval, the cochlear implant and Tactaid 7 participants demonstrated similar imitative consonant production abilities. After an average of 1.5 yr of device use, the cochlear implant participants demonstrated significantly greater gains than did the Tactaid 7 participants for the features of voicing and place of articulation. Although the cochlear implant participants showed a trend towards better production of the consonant manner features, this difference failed to reach significance. CONCLUSIONS: The current results suggest that the use of a multichannel sensory aid yields improvements in consonant feature production. Furthermore, use of a cochlear implant appears to promote the production of consonant voicing and place features to a greater degree than does the use of a multichannel tactile aid.     

Effort as a determinant of choice in rats.

Studied the effect of response effort on rate of responding and choice behavior in a 2-bar situation in 2 experiments with 17 male Sprague-Dawley rats. Exp I used a limited test session and tested at a single FR ratio. Exp II employed a free behavior situation, in which total daily water intake was obtained by barpressing. Ratio requirements beginning with continuous reinforcement and followed by sessions of FR 5, 10, 20, 40, 80, 120, and 160 were tested. Relations between response rate and preference behavior were schedule dependent. On low-ratio schedules the highest response rates and preference were for the light bar. As the ratios were increased, however, response rates became higher and preference was switched to the heavy bar. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Victimization as a determinant of eyewitness accuracy.

Eyewitness identification research frequently uses a simulated crime paradigm, yet the witnesses in these studies are seldom themselves the victims of the crime. To the degree a witness is more personally involved (as a victim), eyewitness identification accuracy and confidence might be modified. 66 undergraduates were randomly assigned to 3 eyewitness conditions: no-theft control, impersonal calculator theft, or personalized watch theft. Whereas the victims in the watch-theft condition were more accurate than Ss in the other 2 treatments, they were not significantly more accurate than witnesses to the less personal calculator theft. Eyewitnesses' accuracy was unrelated to their confidence in their identification. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mitochondrial function as a determinant of recovery or death in cell response to injury

Many pathological conditions can be the cause or the consequence of mitochondrial dysfunction. For instance anoxia, which is initiated by a critical reduction of oxygen availability for mitochondrial oxidations, is followed by a wide variety of mitochondrial alterations. A crucial role in the evolution of cell injury is to be attributed to the direction of operation of the F0F1 ATPase, which may turn mitochondria into the major consumers of cellular ATP in the futile attempt to restore the proton electrochemical gradient. On the other hand, functional mitochondria can paradoxically accelerate or exacerbate cell damage. This concept is particularly relevant for the ischemic myocardium. Indeed, inhibition of the respiratory chain or addition of uncouplers of oxidative phosphorylation can both limit the extent of enzyme release in the intact heart and prevent the onset of irreversible morphological changes in isolated myocytes. From studies on different tissues in a variety of pathological conditions a general consensus emerges on the role of intracellular Ca2+ overload as a pivotal link between cellular alterations and mitochondrial dysfunction. Oxidative phosphorylation is reduced by a massive mitochondrial uptake of Ca2+, resulting in a vicious cycle whereby the reduced ATP availability is followed by a failure of the mechanisms which extrude Ca2+ from the sarcoplasm. In addition, the rise in [Ca2+]i could promote opening of the cyclosporin-sensitive mitochondrial permeability transition pore, leading to a sudden deltapsi(m) dissipation. Here, we review the changes in intracellular and intramitochondrial ionic homeostasis occurring during ischemia and reperfusion. In particular, we evaluate the potential contribution of the permeability transition pore to cellular damage and discuss the mechanisms which can determine the cellular fate from a mitochondrial point of view.     

Receptor noise as a determinant of colour thresholds

Inferences about mechanisms at one particular stage of a visual pathway may be made from psychophysical thresholds only if the noise at the stage in question dominates that in the others. Spectral sensitivities, measured under bright conditions, for di-, tri-, and tetrachromatic eyes from a range of animals can be modelled by assuming that thresholds are set by colour opponency mechanisms whose performance is limited by photoreceptor noise, the achromatic signal being disregarded. Noise in the opponency channels themselves is therefore not statistically independent, and it is not possible to infer anything more about the channels from psychophysical thresholds. As well as giving insight into mechanisms of vision, the model predicts the performance of colour vision in animals where physiological and anatomical data on the eye are available, but there are no direct measurements of perceptual thresholds. The model, therefore, is widely applicable to comparative studies of eye design and visual ecology.     

Social context as a determinant of sex differences in adults' attraction to infants.

70 male and 70 female undergraduates in same- or mixed-sex groups publicly or privately judged pictures of subhuman primate infants and adults for attractiveness. Sex differences were significant but the largest difference between males and females was found when judgments were made in public same-sex groups. Females reported greater attraction to infants relative to their attraction to adults, when judgments were made publicly in all-female groups. Males reported less attraction to infants in all-male public groups than when in private. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal encoding as a determinant of blocking.

A blocking paradigm with rats was used to evaluate whether different temporal information is encoded in simultaneous rather than forward associations. During Phase 1, the blocking CS was simultaneously or forward paired with a unconditioned stimulus/stimuli (UCS). During Phase 2, the pretrained CS occurred in compound with a novel target CS that was paired in a simultaneous or forward manner with the UCS. Forward pretraining resulted in more blocking of a forward than a simultaneously trained target CS, and simultaneous pretraining resulted in more blocking of a simultaneously than a forward trained target CS. Thus, greater blocking occurred when the blocking and blocked CSs had the same temporal relation to the UCS. The results support the temporal coding hypothesis and question the necessity of predictive information in blocking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Proportion of light to cycle as a determinant of critical flicker-fusion frequency.

On the basis of recent studies a meaningful relationship between CFF and the proportion of light to the total cycle (PL) is emerging. Graphs of the Log of time of one dark period to time of one light period "show that increase in time of light, luminance and/or area of test patch, results in a decrease in the time of dark necessary at fusion." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decrease in accessible thiols as an index of oxidative damage to membrane proteins

The effect of several oxidative agents (hydrogen peroxide, tert-butyl hydroperoxide, menadione, AAPH, peroxynitrite and ionizing radiation) on the ratio of weakly to strongly immobilized residues of erythrocyte membrane-bound maleimide-tempo spin label (h(w)/h(s) ratio) was studied in order to test the hypothesis that a decrease in the h(w)/h(s) ratio may be a general index of oxidative damage to membrane proteins. Most of the agents studied decreased though H2O2 almost did not affect and ionizing radiation increased the h(w)/h(s) ratio. In parallel, the ratio of DTNB accessible/DTNB inaccessible membrane protein-SH groups was determined from membrane-SH group measurements with the Ellman reagent in the absence and in the presence of sodium dodecyl sulfate. This ratio decreased in all cases studied and seems to be a more universal and easy to measure parameter to describe the oxidative damage to membrane proteins.     

Perception of abilities as a determinant of performance.

Studied the relationship between performance effectiveness and perceived possession of required abilities among 64 clerical workers in a public organization. The hypothesis that high performers perceive themselves as having more or higher levels of job-required abilities than do poor performers was supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personal involvement as a determinant of argument-based persuasion.

Hypothesized that when a persuasive communication was on a topic of (a) high personal relevance, attitude change was governed by issue-relevant arguments, and (b) low personal relevance, peripheral features were more important. 145 undergraduates expressed their attitudes on the issue of comprehensive senior exams after exposure to a counterattitudinal advocacy that was of high or low personal relevance containing either strong or weak arguments that emanated from a source of either high or low expertise. Another 18 Ss were controls who were surveyed but not exposed to a counterattitudinal advocacy. Interactions of the personal relevance manipulation with the argument quality and expertise manipulations revealed that under high relevance (the exams were to be instituted the following year), attitudes were influenced primarily by the quality of the arguments in the message, whereas under low relevance (the exams were to be instituted in 10 years), attitudes were influenced primarily by the expertise of the source. It is suggested that an increase in involvement is associated with an increase in the importance of message arguments because people are motivated to hold "correct" and defensible opinions, and they have a better framework for things that are relevant to the self. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lean body mass as a determinant of thyroid size

A controlled study was performed in 18 viral cirrhosis patients to evaluate whether immune function, as indicated by natural killer (NK) cell activity, was improved by a branched-chain amino acid-enriched nutrient mixture (nutrient-mixture), Aminoleban EN. Five patients received the nutrient-mixture (100 g/day) for 2 to 6 weeks preceded by control periods. Five additional patients received the nutrient-mixture for 2 to 4 weeks, and the remaining 8 patients did not receive the nutrient-mixture. NK cell activity, CD16, CD8, CD11b, and amino acids were assayed before and after the administration of the drug in the nutrient-mixture-supplemented group, and two times with 1 to 6 month intervals in the control group. In the nutrient-mixture-supplemented group (n = 10), increasing NK cell activity, expressed as the ratio of values of post-treatment to that of baseline (ratio > 1.25) was detected in 7 (70%) patients, whereas in the control group (n = 13), it was detected in only 1 (7.7%) (p < 0.01). While in the affected group (NK cell activity ratio > 1.25, n = 7), all patients had compensated liver cirrhosis, in the unaffected group (NK cell activity ratio < 1.25, n = 3), 2 of 3 patients had decompensated liver cirrhosis (p < 0.02). Laboratory data, indicating severity of liver cirrhosis, such as total bilirubin and albumin, showed better values (p < 0.01, p < 0.05 respectively), and baseline NK cell activity was low (8.7 +/- 7.2% vs 33.3 +/- 13.0%, p < 0.05) in the affected group than unaffected group. NK cell subpopulations such as CD16 (%), CD11b (%) and one of the populations of T cell such as CD8 (%) showed no significant change throughout the study. As for amino acids analysis, Fischer's ratio was increased in the nutrient-mixture-supplemented group compared to the control group (p < 0.05), but none of the amino acids showed significant change. Thus the changes in NK cell activity were not explained by increase in NK cell subpopulations nor changes of amino acids. These results suggest that the branched-chain amino acid-enriched nutrient mixture increases NK cell activity moderately in patients who have compensated liver cirrhosis and shows lower values of baseline NK cell activity.