The benefits of positive illusions: Idealization and the construction of satisfaction in close relationships.

It is proposed that satisfaction is associated with idealistic, rather than realistic, perceptions of one's partner. To provide baselines for assessing relationship illusions, both members of married and dating heterosexual couples were asked to rate themselves and their partners on a variety of interpersonal attributes. Participants also rated the typical and ideal partner on these attributes. Path analyses revealed that individuals' impressions of their partners were more a mirror of their self-images and ideals than a reflection of their partners' self-reported attributes. Overall, intimates saw their partners in a more positive light than their partners saw themselves. Furthermore, these idealized constructions predicted greater satisfaction. Individuals were happier in their relationships when they idealized their partners and their partners idealized them. Taken together, these results suggest that a certain degree of idealization or illusion may be a critical feature of satisfying dating and even marital relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Force and intracellular Ca2+ during NANC-mediated relaxation of rat anococcygeus muscle and the effects of cyclopiazonic acid

1. Simultaneous recordings of tension and [Ca2+]i during NANC-mediated relaxation were made in the rat anococcygeus muscle under various conditions. 2. In muscles precontracted with guanethidine, nitrergic stimulations at 2 Hz produced a rapid decrease in both the tension and [Ca2+]i. 3. The nitric oxide synthase inhibitor, NG-nitro-L-Arginine (NOLA, 100 mumol/L) completely abolished the decreases in the [Ca2+]i and force response of the NANC-mediated relaxation. 4. Noradrenergic-mediated contractions elicited by electrical field stimulation were potentiated by the addition of NOLA. In the absence of NOLA, the motor responses were larger in magnitude at 10 Hz stimulation than at 2 Hz. After NOLA, both the force response and the associated rise in [Ca2+]i were substantially increased in comparison to the control stimulations. Proportionately the potentiation of the 2 Hz response was of a far greater magnitude than that of the 10 Hz response. 5. The guanylate cyclase inhibitor methylene blue (10 mumol/L), partially inhibited the force and [Ca2+]i response of the NANC relaxation. 6. Following exposure of the muscles to the sarcoplasmic reticulum Ca(2+)-ATPase inhibitor, cyclopiazonic acid, (10 mumol/L) the responses to NANC stimulation were inhibited. The attenuated relaxation response displayed a bi-phasic timecourse and the Ca2+ change in comparison to that of the control was markedly smaller. In some cases, a relaxation was observed with no detectable change in the [Ca2+]i. 7. The results suggest that part of the relaxation response observed with NANC-mediated relaxation in the rat anococcygeus is dependent on Ca2+ sequestration into the sarcoplasmic reticulum. However, other Ca2+ lowering mechanisms and possible Ca2+ independent mechanisms may also contribute to the NANC relaxation response.     

Effects of dietary gossypol consumption on metabolic homeostasis and reproductive endocrine function in beef heifers and cows

Our objectives were to determine the effects of incremental increases in dietary gossypol on metabolic homeostasis and reproductive endocrine function in postpubertal beef heifers and the long-term effects of elevated dietary gossypol on various metabolic and reproductive endocrine characteristics in mature cows. In Exp. 1, heifers (n = 6/group) were fed either 0, .5, 2.5, 5, 10, or 20 g.animal-1 x d-1 of dietary free gossypol for 62 d. Erythrocyte membrane osmotic fragility was increased (P < .0001) in both the 10- and 20-g groups. Slight alterations in plasma concentrations of sorbitol dehydrogenase and K+ were also detected in the latter group. Treatment did not affect ADG, body condition scores, or concentrations of progesterone during the estrous cycle; however, mean concentrations of LH were higher (P < .001) in heifers fed 20 g/d of gossypol than in heifers in all other groups. In Exp. 2, lactating cows (n = 17) exhibiting regular estrous cycles were fed a control (no gossypol, n = 8) or high-gossypol (20 mg.kg BW-1 x d-1 free gossypol, n = 9) diet for 33 wk. Mean BW and body condition scores did not differ during the feeding period. Erythrocyte membrane fragility was greater (P < .05) in the high-gossypol than in the control group. Magnitude of the preovulatory LH surge, luteal phase concentrations of progesterone, follicular fluid concentrations of estradiol and progesterone, in vitro granulosa cell estradiol production, and 60-d pregnancy rates were similar between groups. The amounts of gossypol fed in these experiments are not likely to affect reproductive performance adversely in beef heifers or cows.     

Bony healing of large cranial and mandibular defects protected from soft-tissue interposition: A comparative study of spontaneous bone regeneration, osteoconduction, and cancellous autografting in dogs

The purpose of this study was to compare spontaneous bone regeneration, osteoconduction, and bone autografting in critical size calvarial and mandibular defects (defects which do not heal spontaneously during the lifetime of the animal) that were protected from soft-tissue interposition. Eighteen adult mongrel dogs underwent osteotomies to create a unilateral 30-mm segmental defect in the midbody of the edentulated right mandible and bilateral 15-mm x 20-mm full-thickness window defects in the parietal bones. The defects were either left empty, implanted with coralline hydroxyapatite (HA) blocks, or autografted with iliac cancellous bone. All defects were protected with a macroporous titanium mesh and the segmental mandibular defects were additionally stabilized by internal plate fixation. Specimens were retrieved after 2 and 4 months and three undecalcified longitudinal central sections including the osteotomy interfaces were prepared from each specimen for histometry and histology. Sections were analyzed for volume fractions of bone, soft tissue, and implant using scanning electron microscopy, backscatter electron imaging and histometric computer software. In the mandibular model, the empty defects exhibited the greatest amount of bone formation after 4 months (47.3 percent), which was greater than the amount of bone in the autografted group (34.8 percent) and significantly greater than the amount of bone within the hydroxyapatite implants (19.0 percent, p < 0.05). In the cranial defects, the autografted specimens demonstrated the greatest volume fraction of bone after 4 months (27.3 percent), which was significantly greater than within both the empty defects (18.2 percent, p < 0.05) and the hydroxyapatite implants (18.2 percent, p < 0.05). New bone formation in the mandibular defects united the cut ends at 4 months regardless of treatment and originated predominantly from the periosteum which remained present only along the alveolar border after surgical closure. In the calvarial defects, periosteum was not preserved and bone regenerated centripetally, originating from the diplo? without any evidence of dural osteogenesis. Bone bridging was incomplete in the empty cranial defects at 4 months. In both the mandibular and cranial specimens, new bone at 2 months was a mixture of woven and parallel fibered bone. At 4 months, the new bone had remodeled almost entirely into mature Haversian bone. This study demonstrated a remarkable ability of defect protection with a macroporous protective sheet to facilitate bone regeneration in critical size mandibular and cranial bone defects. When active osteogenic periosteum was present, as in our mandibular model, we concluded that defect protection alone was sufficient to allow for healing even of critical size defects. When periosteum was absent as in our cranial defects, the limited spontaneous bone formation benefited from the added contributions of cancellous grafting and osteoconductive implants, both of which promoted bone bridging across the defects. We suggest that in the future a resorbable macroporous protective sheet would be advantageous in comparison to a titanium mesh to facilitate bone regeneration by preventing soft-tissue prolapse and allowing the migration of mesenchymal cells and the proliferation of blood vessels from the adjacent soft tissues into the bone defect. Finally, this study identified the need to differentiate critical size defects into those with and without defect protection and periosteum.     

Collagen fibrils forming in developing tendon show an early and abrupt limitation in diameter at the growing tips

The formation of very long and near-uniform diameter collagen fibrils is fundamental to the assembly of the extracellular matrix of animals. However, how growth in length and diameter is regulated, and how fibrils increase in diameter during development, are poorly understood. The approach in this study was to examine the tips and central shaft regions of fibrils from 12 and 18-day embryonic chick metatarsal tendon using quantitative mass mapping electron microscopy. We found that the fibrils had smoothly tapered C and N-terminal tips, which had linear axial mass distributions and were consequently parabolic in shape. An invariant feature of all tips (N and C) was an abrupt stop in lateral growth leading to a local plateau in diameter. The distance from the end of the fibril to the abrupt stop occurred at multiples of five D-periods (where D=67 nm). This implies that D-periods at the ends of fibrils are not equivalent sites for accretion, and that diameter regulation relies on surface structural features, which repeat every 5D. Mass mapping of entire fibrils at day 12 showed that, on average, the coarseness of the fibril tips was independent of fibril length, consistent with individual fibrils growing at constant tip shape. Comparison of diameters in the plateau (close to the tips) and shaft regions of the fibril showed that fibrils in day 12 tendons grow in length at constant diameter. Analysis of tendons from day 18 embryos showed that the increase in diameter at this stage of development was the result of both increases in the coarseness of the tips and continued lateral accretion of mass onto the central shafts at distances away from the growing tips. Regulated tip growth provides an attractive explanation for how cells are able to synthesise very long fibrils during the organisation of the extracellular matrix.     

Feeding practices and growth among low-income Peruvian infants: a comparison of internationally-recommended definitions

BACKGROUND: Data from a longitudinal study of 153 low-income Peruvian infants were used to assess the relationship between internationally-recommended definitions of feeding practices and infants' monthly weight gain and weight status at 12 months. METHODS: Infants were classified into feeding categories using monthly reported data. Analysis of variance was used to assess the relationship between reported usual feeding practices and growth. Reported breastfeeding practices were compared to observed breastfeeding practices and to weighted breast milk intakes to determine the validity of recommended breastfeeding definitions. RESULTS: Breastfed infants who consumed non-human milks during the first month of life gained less weight during that month (P < 0.002) than exclusively and predominantly breastfed infants. Reported daily nursing frequency was associated with observed nursing frequency and breast milk energy intake (P < 0.05) for infants < 9 months old. Patterns of growth varied according to early diets. Infants who consumed breast milk and non-human milks and those who were fully weaned by 4 months were more likely to be underweight at 12 months than other infants. Infants classified as token breastfeeders ( < or = 3 times/24 hours) from 0 to 120 days had monthly gains that were similar to those of fully weaned infants. CONCLUSIONS: Infants feeding definitions should 1) continue to differentiate exclusively breastfed infants from other infants who are almost exclusively or predominantly breastfed; 2) distinguish partially breastfed infants who consume only non-breastfeeding frequency or the % of their total daily energy that comes from breast milk.