Behavioral strategies in the cold: effects of feeding and nesting costs.

Animals can meet energetic challenges by acquiring or conserving energy. In the present experiment, we pitted these strategies against each other by housing rats in a cold environment and requiring them to bar press for food pellets and for access to a heated nest. Our question was how rats would exploit these resources to meet the added energetic demand of the cold when food was abundant or scarce. Results showed that rats' allocation of time and effort between competing activities was a function of demand. Feeding and nesting were partially substitutable in the cold: rats traded food for warmth and vice versa, economizing on both time and energy by adjusting their feeding and nesting patterns. Depending upon food abundance and the cost of nesting, rats acquired calories from food, conserved calories by nesting, and borrowed calories from the defense of body weight.

Communal reproductive success in rats (Rattus norvegicus): effects of group composition and prior social experience.

We compared the reproductive success and maternal behavior of sibling pairs of female Long-Evans rats (Rattus norvegicus) housed together from birth (familiar) to that of pairs of unrelated females housed apart during development (unfamiliar). Sires either remained in the colonies through weaning of their pups or were removed before parturition. Familiar animals reared more pups to weaning, were more likely to share in caring for their pups, and were less likely to exhibit infanticide than were unfamiliar ones. The presence of males in cages with pups had no direct effect on the reproductive success of females, but female pairs housed with males spent less time than female pairs housed alone caring for pups together in a combined nest. Conflicting evidence for communal rearing in populations of wild rats may reflect differences in the genetic relatedness or early social experience of female rats.

Control of human aggression. A comparative perspective.

Recent animal research has demonstrated that humans are not a uniquely aggressive species and that even in so-called violence-prone animals, aggression is always an optional strategy. Although some form of intraspecific aggression exists in every vertebrate species studied thus far, it is also true that all organisms have coevolved equally potent inhibitory mechanisms that enable them to use an aggressive strategy selectively or to suppress aggression when it is in their interest to do so. Parallel studies of aggression in children, assaultive adults, and even entire societies have suggested that humans are exquisitely sensitive to subtle social controls that could be used to reduce the frequency of individual acts of violence.

Defective cAMP-dependent phosphorylation of intact T lymphocytes in active systemic lupus erythematosus.

The present study was undertaken to establish whether cAMP-dependent phosphorylation of endogenous substrates is impaired in T lymphocytes from subjects with active systemic lupus erythematosus (SLE). In normal human T lymphocytes, the cell-permeable cAMP analog, N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate, induced phosphorylation of substrates with molecular masses of 17.5, 23/25, 33.5 kDa on one-dimensional SDS/PAGE. Maximal phosphorylation occurred at 60 min. In contrast to healthy T cells, the extent of substrate phosphorylation achieved in active SLE T cells (n = 8) was only 15% at 60 min in the 17.5-kDa substrate, 21% in the 23/25-kDa substrate, and 9% in the 33.5-kDa substrate. The rheumatic disease controls (rheumatoid arthritis; primary Sjögren syndrome; n = 8) exhibited a mean 72%, 124%, and 85%, respectively, of phosphorylation observed in healthy T cells. Because the only known mechanism by which cAMP acts is via cAMP-dependent protein kinase (protein kinase A), these data raise the possibility of a defect at the level of this kinase in SLE T lymphocytes.

Effects of flossing on plaque and gingivitis in third grade schoolchildren.

The purpose of this investigation was to determine whether flossing, as an adjunct to toothbrushing, performed in a school-based program can contribute significantly to a reduction in gingivitis. Four volunteer third grade classrooms (n = 112) were randomly assigned to finger-floss, looped-floss, flossholder, and brushing-only control group. Measures taken at baseline and in four weeks included gingival (GI), plaque (PI), and flossing dexterity indices (FDI). Results using ANOVA showed no differences in PI among groups. However, both brushing-only and finger-floss groups showed GI scores significantly lower than the looped-floss group. A repeated measures ANOVA revealed that the finger-floss group improved gingivitis scores most over time, while the flossholder group improved scores the least. The ANCOVA results with FDI showed that at the final measurement, looped-floss manual dexterity was rated significantly better than finger-floss and that both groups were rated better than flossholder. Final indications are that toothbrushing alone can produce clinical results similar to use of a combination of toothbrushing and flossing.

Effects of fluprazine hydrochloride on maternal behaviour in mice.

Fluprazine hydrochloride treatment disrupted both retrieval and nursing components of maternal behaviour when dam and pups were separated for a 30 min post-infection interval. Subsequent experiments revealed that pup contact during this interval, even when restricted to visual/auditory stimulation, abolished the drug's effect on nursing but not retrieval. Fluprazine appears to strongly and consistently disrupt retrieval while its effects on nursing appear more indirectly mediated. The data clearly reveal that the drug's effects extend to maternal behaviour as well as aggression, male copulation, play and various fear-motivated behaviours. This range of behavioural effects may limit its usefulness in the reduction of aggression.

Characterization of the human T lymphocyte adenosine receptor: comparison of normal and systemic lupus erythematosus cells.

To determine whether a defect in the T cell response to adenosine exists at the level of the adenosine receptor in systemic lupus erythematosus (SLE) we measured the binding affinity and maximum binding of T cell membranes from both normal and SLE T cells by utilizing radiolabeled adenosine ligands. Normal T lymphocyte membranes possess a single class of [3H]5-N-ethylcarboxamide adenosine binding sites with a Kd of 0.61 microM, a Bmax of 23.5 pmol/mg protein, and a Hill coefficient of 0.98, which indicates the presence of noncooperative sites. In contrast, T cell membranes do not bind significant amounts of either [3H]cyclohexyladenosine or [3H]phenylisopropyladenosine. These data indicate that T lymphocyte membranes have only A2, and not A1, adenosine receptors. Similarly, T cells from both active and inactive SLE subjects also express only A2 receptors with a Kd of 0.93 microM, a Bmax of 20.4 pmol/mg protein, and a Hill coefficient of 0.85, which is consistent with the presence of noncooperative sites. There is no difference in the on-rate, affinity, or density of T cell A2 receptors from active SLE patients, inactive SLE patients, or healthy controls. We conclude that T lymphocytes from both healthy and SLE subjects express A2, but not A1, receptors. Thus, the inability of SLE T cells to respond to adenosine does not reflect a decreased density of A2 (stimulatory) receptors, diminished A2 receptor binding, or an increased affinity or number of A1 (inhibitory) adenosine receptors. These observations support the conclusion that the defect in the T cell cAMP-dependent pathway may occur at a point distal to the adenosine receptor.

Mobility of the human T lymphocyte surface molecules CD3, CD4, and CD8: regulation by a cAMP-dependent pathway.

The present study was undertaken to determine whether a cAMP pathway mediates the mobility of CD3, CD4, and CD8 within the membrane. Crosslinking CD3, CD4, and CD8 with monoclonal antibody and anti-antibody induced rapid accumulation of intracellular cAMP, occupancy of cAMP receptors, and was temporally associated with the mobilization and directed movement of these molecules to a pole of the cell. This capping process could be partially inhibited in a dose-dependent manner by treatment of T cells with 2',5'-dideoxyadenosine, a ribose-modified adenosine analogue that binds to the P site of the catalytic subunit of adenylate cyclase and reduces adenylate cyclase activity. Furthermore, inhibition of cAMP-dependent endogenous phosphorylation of 17.5-kDa, 23/25-kDa, and 33.5-kDa bands in intact T cells by N-[2-(methylamino)ethyl]-5-isoquinoline-sulfonamide, a cell-permeable inhibitor of cyclic nucleotide-dependent protein kinase, blocked the capping event. Data support the conclusion that crosslinking of CD3, CD4, and CD8 activates a cAMP-dependent pathway that mediates the mobilization and directed movement of these molecules. cAMP-dependent protein phosphorylation is an integral step leading to the capping process.

Eicosanoid metabolism by Leishmania donovani-infected macrophages: mouse strain responses in prostanoid synthesis.

Arachidonic acid (20:4) conversion to prostanoids was examined in murine peritoneal macrophages infected in vitro with Leishmania donovani. Four strains of mice differing in resistance to in vivo L. donovani infection were studied. Normal macrophages from all strains converted 20:4 to prostanoids and this was augmented by L. donovani infection. Although cells from each strain synthesized elevated levels of prostaglandin-E2 (PGE2), there were differences with respect to relative increases of this product, with infected macrophages from the C3H/HeJ strain showing the smallest increase above basal levels. These results indicate that macrophages from mouse strains with distinct levels of in vivo resistance to L. donovani all respond to infection with augmented prostanoid synthesis. Although some heterogeneity in strain-specific PGE2 responses to in vitro infection were observed (with respect to increases in PGE2 synthesis above basal levels), it is unlikely that differential resistance of these strains to in vivo infection is strictly related to these relative differences. It seems likely that other genetically controlled factors may have a major impact on disease expression.

Effects of fluprazine hydrochloride on conspecific odor preferences in rats.

The effect of Fluprazine Hydrochloride (DU 27716) on preference for conspecific male, estrous female and food odors was examined in male rats utilizing a two-compartment choice apparatus. Treatment with 8.0 mg/kg Fluprazine enhanced the preference of males for male odors but had no effect on preference for either estrous female or food odors. The drug-induced enhancement of male odor preference is consistent with the suggestion that Fluprazine interferes in some way with the processing of olfactory stimuli which normally precede offensive attack. The failure of the drug to alter the preference of males for estrous female odors suggests that the increased sniffing of estrous females noted during social testing may be secondary to other sources of conspecific stimulation or may reflect a highly transitory effect on olfactory processes. These results suggest that the suppressive effects of Fluprazine on intermale aggression and copulation are mediated by somewhat distinct mechanisms.

Outcome evaluation of behavioral parent training and client-centered parent counseling for children with conduct problems.

The central question addressed was, how effective is parent training in reducing conduct problems in children in comparison to client-centered parent counseling? A secondary question was the relative effectiveness of the two treatment groups in comparison to a wait control group that when untreated during the 8-week period of treatment provided the other groups. Families of 36, 5- to 12-year-old conduct problem children were screened and assigned at random to treatment groups, but wait control group assignment depended upon therapist availability. Supervised graduate student therapists conducted 10 treatment sessions for each family. Parent reports and paper and pencil tests of child deviance and parent satisfaction showed a superior outcome for behavioral over the client-centered and wait control groups, and no differences between the latter two groups. At follow-up there was no maintenance of this superiority. Home observation data showed no advantage of behavioral over client-centered treatment, and these two groups did not improve significantly more than the wait control group. These results were discussed in the light of possible interactions between treatment and measurement, and methodological and sampling differences between this and other studies.