bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organization of the stretch response to milk in the rat fetus
Authors: Robinson Scott R. , Smotherman William P. 
Published: January 2005

AbstractIntraoral infusion of milk reliably elicits a stretch response in the rat fetus. The fetal stretch response appears isomorphic to the stereotypic behavior exhibited postnatally by suckling rat pups during milk ejection. Using a procedure that permits direct fetal observation, milk infusions were delivered to rat fetuses on Day 20 or 21 of gestation. Infusion of milk promoted systematic changes in fetal behavior that culminated in expression of the stretch response nearly 3 min later. Interruption of this behavioral sequence prevented stretching, suggesting that a period of behavioral reorganization after milk infusion is necessary but not sufficient for the stretch response to occur. The behavioral sequence initiated by the fetal rat's first exposure to milk is remarkably similar to the behavior exhibited by experienced infant rats at the nipple. © 1992 Wiley & sons. Inc.
Temperature‐dependent effects of maternal separation on growth, activity, and amphetamine sensitivity in the rat
Authors: Zimmerberg Betty , Shartrand Angela M. 
Published: January 2005

AbstractThis study was conducted to examine the effects of an early stressor, maternal separation, on development, arousal, and sensitivity to amphetamine in the rat. Rat pups were maternally separated at nest temperature (WARM), room temperature (COLD), or nest temperature with agitation (AGIT) for 6 hr each day from 2 to 15 days of age. A control group (CONT) remained with the mother in the nest during this time. COLD subjects were developmentally delayed and had lower body and brain weights than the other three groups into adulthood. WARM and AGIT subjects (both maternally separated at nest temperature) had significant growth delays compared to CONT, but grew more quickly than COLD subjects. COLD subjects were less active than the other maternally separated groups, and WARM and AGIT groups were more active. Activity did not differ at 28 or 75 days of age. However, adult WARM subjects were less sensitive and COLD subjects were more sensitive to amphetamine as measured by locomotor activity than CONT and AGIT subjects, who did not differ from each other. The relationship between early stress, changes in dopaminergic systems, and altered drug responsiveness are discussed in terms of the implications for the etiology of drug abuse. © 1992 Wiley & sons. Inc.
Ultrasonic vocalizations by rat pups: The primary importance of ambient temperature and the thermal significance of contact comfort
Authors: Blumberg Mark S. , Efimova Inna V. , Alberts Jeffrey R. 
Published: January 2005

AbstractWe investigated the effects of isolation, huddling, and air temperature on ultrasound production by rat pups. Experiment 1 showed that ultrasound production by 8‐ to 9‐day‐olds was minimal at thermoneutrality and increased in response to small deviations of air temperature on either side of the thermoneutral zone. Experiments 2 and 3 showed that suppression of ultrasound production by contact with littermates is consistent with the thermal consequences of huddling. Experiment 4 showed that, contrary to previous conclusions, ultrasound production is not independent of ambient temperature in pups older than 10 days of age. Taken as a whole, these experiments emphasize (1) the importance of ambient temperature for the elicitation of ultrasound by rat pups of all ages studied, (2) the importance of thermal factors in the suppression of ultrasound by littermate contact, and (3) the manner in which different methods can change interpretations of the behavior and physiology of infant rats. © John Wiley & Sons, Inc.
Quinpirole alters quadruped activity in rats from the second postnatal week
Authors: Eilam David , Szechtman Henry , Spear Linda P. 
Published: January 2005

AbstractThe present study shows that the effects of quinpirole (1 mg/kg) during the second postnatal week but not before resemble the effect of the drug in adult rats in increasing quadruped activity, eliminating grooming, reducing lateral bending, and stimulating verticalized turning. Quinpirole also modifies the morphology of turning behavior, the primary from of coordinated quadruped locomotion in neonate laboratory rat pups. Under saline, turning involves lateral bending and straightening of the trunk. Under quinpirole, turning includes a vertical component of movement (“verticalized turning”) instead of the normal lateral bending of the trunk. A similar trend of change in turning is induced by quinpirole in adult rats: An acute injection reduces lateral bending, and a chronic treatment increases verticalization. The induction of vertical turning in the second but not the first postnatal week may stem from the normal course of development since typical vertical movements of intact rats (supported rearing and wall climbing) develop only by the age of 11–14 postnatal days. Verticalized turning may be thus a drug‐induced expression of an age‐related tendency to perform vertical movements. © John Wiley & Sons, Inc.
Blood pressure increases in response to feeding in the term neonate
Authors: Cohen Morris , Witherspoon Mary , Brown David R. , Myers Michael M. 
Published: January 2005

AbstractWe studied blood pressure and heart rate of 18 medically well newborn babies before, during and after feeding. Seven were breast‐fed and 11 bottle‐fed and all were studed between 24 and 92 hr of age. There was an increase in heart rate associated with sucking on a pacifier but no additional increase with feeding. By 30–60 min after feeding, heart rate had returned to baseline value. Blood pressure, however, did increase in response to feeding and showed a greater increase in the breast‐fed group than in the bottle‐fed group. Systolic blood pressure rose from 72 mmHg in the basal state to 85 mmHg during the first 3 min of feeding in the bottle‐fed babies and from 73 to 99 mmHg during comparable periods in the breast‐fed babies. The results for diastolic blood pressure were similar except that changes within the bottle‐fed group were not statistically significant. Bottle‐fed babies rose only from 42 to 47 mmHg while breast‐fed babies rose from 42 to 61 mmHg from basal conditions to feeding. Blood pressure responses to feeding may have implications for susceptibility to necrotizing enterocolitis, for future blood pressure liability in adulthood and for later hypertensive disease. © John Wiley & Sons, Inc.
Behavioral selection of odor cues by young female mice affects age of puberty
Authors: Drickamer Lee C. 
Published: January 2005

AbstractFemale house mice were reared from weaning at 21 days of age until first vaginal estrus in 40 1 aquaria in which they were given a choice of exposing themselves to bedding placed on opposite halves of the aquarium floor and sprayed with water or urine containing puberty‐influencing chemosignals. In Experimental 1, mice housed with only male urine cues sprayed on the bedding matured significantly earlier and mice housed with only grouped female urine sprayed on the bedding matured significantly later than control mice where water was sprayed on the bedding for both halves of the aquarium. In Experiment 2, there were no significant differences in mean ages at vaginal introitus or first estrus for females reared with choices between (a) bedding sprayed with male urine versus bedding sprayed with water, (b) bedding sprayed with urine from grouped females versus bedding sprayed with water, (c) bedding sprayed with male urine versus bedding sprayed with urine from grouped females, or (d) the control condition where both sides of the aquarium contained bedding sprayed with water. Analysis of continuous video tapes of the locations of the females for Experiment 2 revealed that females chose initially to spend more time on the half of the floor with bedding that delayed puberty relative to the other side, but shifted their preference toward a more puberty‐enhancing signal at about the time of first estrus. Female house mice appear to be able to exert some behavioral control over their own sexual maturation. © 1992 Wiley & sons. Inc.
Postpartum factors related to mother's attraction to newborn infant odors
Authors: Fleming Alison S. , Corter Carl , Franks Patrícia , Surbey Michelle , Schneider Bruce , Steiner Meir 
Published: January 2005

AbstractHedonic responses to a variety of infant (general body, urine, and feces) and noninfant (lotion, cheese, and spice) odorants were compared in four groups of subjects: new mothers, mothers a 1‐month pospartum, and female and male nonparents. Using standard scaling procedures, subjects rated each of the odorants twice on a scale from extremely unpleasant (−20.5) to extremely pleasant (+20.5). In addition, all subjects completed a set of attitude questionnaires, and mothers also answered a childbirth questionnaire and were observed while feeding their infants © 1993 John Wiley & Sons, Inc.
The effect of age on children's learning of problems that require a configural association solution
Authors: Rudy Jerry W. , Keith Julian R. , Georgen Kathleen 
Published: January 2005

AbstractElemental associations permit subjects to solve problems when the significance of the relevant stimulus elements are consistent from trial to trial but do not allow subjects to solve problems that require them to construct and use representations of stimulus conjunctions or configurations to guide their behavior. Recent research with brain‐damaged and developing animals has led several theorists to propose that elemental and configural associations depend on different neural systems. Some evidence suggests that changes in children's learning that occur when they are about 4.5 year old may be partially due to developmental differences in access to the elemental and configural association systems. Two experiments are reported that support this hypothesis. Children at least 4.5 years old were able to solve the transverse patterning problem and a conditional discrimination, two problems that require configural association solutions. Younger children did not solve these problems but were able to solve problems constructed from the same stimulus materials that permitted an elemental association solution. These results suggest that children may not gain access to the configural association system until they are about 4.5 years old and support the hypothesis that the configural association system depends on different, later developing neural structures than does the elemental association system © 1993 John Wiley & Sons, Inc.
Importance of prenatal nutrition to the development of a precocial chick
Authors: Hill Wendy L. 
Published: January 2005

AbstractThe developmental maturity of hatchling birds varies greatly across the altricial‐precocial continuum and these differences are related to the relative proportions of yolk and albumen in a species' egg. In general, the more precocial the chick the greater the proportion of yolk in its egg. Egg composition can also vary within species with unknown consequences for the developing embryo. The present research sought to determine the importance of egg composition to avian development by experimentally removing 1, 2, 4, 8, 12, or 16% of the albumen from eggs of domestic fowl (Gallus gallus). Experimental chicks were paired to control chicks whose eggs were matched on the basis of original mass and laid by the same female but no albumen was removed from their eggs prior to incubation. Decreased levels of albumen significantly decreased chick size at hatch. Experimental subjects, however, had similar growth to controls after 20 days of ad‐lib access to food, although sex differences between pairs indicated that the growth of females may be affected differentially by albumen removal. Righting responses were retarded in experimental subjects for the 2 and 4% albumen‐removal groups. Egg composition can have important consequences for chick survival simply by influencing body size at hatch and it is suggested that the practice of using overall egg size as a measure of egg “quality” needs to be broadened by considering what is inside the egg as well. In addition, the unique opportunity presented by using an avian model to assess directly the specific influences of protein (albumen) and of fat (yolk) on growth and behavioral development is explored. © 1993 Wiley & sons. Inc.
The effects of olfactory experience on nest odor preferences and pup retrieval in rats
Authors: Bauer J. H. 
Published: January 2005

AbstractPrevious studies have shown that maternal rats are attracted to their own bedding and that of other dams but not to that of virgins. The present studies were designed to test two hypotheses: First, that the addition of a novel botanical odor to the bedding of maternal animals would result in subsequent preferences for such an odor. Second, such a preference should enable dams to discriminate between pups odorized with familiar and unfamiliar odors as measured by differential retrieval of the pups. Both hypotheses were confirmed. In addition, we found that preferences established during a first pregnancy and lactation affected the retrieval of pups during a second lactational period, but could be overturned by new olfactory experience during that second lactational period. © 1993 John Wiley & Sons, Inc.
Contextual updating of infants' reactivated memories
Authors: Boller Kimberly , Rovee‐Collier Carolyn 
Published: January 2005

AbstractThe ease with which a reactivated memory is updated is updated has major implications for whether or not a prior memory is likely to be retrieved in the future. In three experiments, we explored this problem with nonverbal human infants, whose newly acquired memory of training in a specific context is readily updated by novel contextual information. In Experiment 1, exposing infants to a novel context immediately after a successful reactivation treatment neither impaired their retention in the original context nor facilitate it in the novel exposure one. In Experiment 2, increasing the delay between the reactivation treatment and exposure to the novel context also failed to facilitate retention in the novel test context. In Experiment 3, the reactivated memory was updated when the contingency was briefly experienced in the novel context immediately after the reactivation treatment. Under these circumstances, previously trained infants exhibited retention in the novel context, but infants who had not been trained 3 weeks earlier or whose original memory had not been reactivated exhibited none. The resistance of a reactivated memory to contextual updating unless the new context is predictive apparently buffers infants′ memories against revision after long delays by contexts that could be inappropriate.© 1994 John Wiley & Sons, Inc.
Juvenile delinquency intervention
Authors: Lipsey Mark W. 
Published: January 2005

AbstractOver the past several decades, skepticism about the effectiveness of juvenile delinquency interventions has increased substantially. However, as the quality of research on this topic has improved, a more optimistic perspective has begun to emerge. To address this issue, the author summarizes three meta‐analyses indicating that interventions to reduce juvenile delinquency may have small but meaningful positive impacts. This systematic literature review also suggests promising avenues for future research.
Paradigm wars: A basis for peaceful coexistence and beyond
Authors: Datta Lois‐ellin 
Published: January 2005

AbstractBoth qualitative and quantitative paradigms have contributed much to evaluations. Both, however, are works‐in‐progress with many issues still unresolved and assumptions incompletely tested. Further, both are more similar in practice than might be expected from the sometimes strident disputes—all grounds for peaceful coexistence and for going beyond to a new perspective.
Plasma membrane of cultured oligodendrocytes: I. Isolation, purification, and initial characterization
Authors: Polak Paul E. , Szuchet Sara 
Published: January 2005

AbstractOligodendrocytes generate myelin as extensions of the plasma membrane. Myelin has been well characterized, yet little is known concerning oligodendrocyte plasma membrane. We have developed a reproducible method for the isolation of an oligodendrocyte plasma membrane‐rich fraction (F2.2). F2.2 has a 25‐fold enrichment in K+‐dependent p‐nitrophenyl phosphatase, a plasma membrane marker. Impurities are composed of Golgi elements (8–12%), microsomes (4–6%), and lysosomal membranes (1–5%). Our starting material was oligodendrocytes kept in culture in a nonattached state for 3 to 5 d. After disrupting the cells and removing nuclei (P1), the supernatant (SP1) was fractionated on a self‐generating 20% Percoll gradient into three bands: F1, F2, and F3. F1 had only 3% of the applied protein and was not characterized. F2, with 11% of the protein, was fivefold enriched in plasma membrane. F3 had 27% of initial protein; it consisted of a crude mitochondrial and lysosomal fraction. F2 was further purified by first washing it hypotonically, treating it with Mg2+, and then fractionating it on a Ficoll step gradient that yielded F2.2 at the interphase. Morphologically F2.2 comprises (1) membranous sheets, often with more than one membrane in close apposition; (2) membrane vesicles of various sizes and shapes frequently filled with amorphous material; (3) Golgi elements; and (4) unrecognizable profiles. The sodium dodecyl sulfate‐polyacrylamide gel electrophoresis protein profile of F2.2 reveals CNPase as a major component in agreement with the high CNPase specific activity (3,860 μmol/mgP/h) found in F2.2 Other significant polypeptides have Mr = 170,000, 135,000, 108,000, 80,000, 53,000, 38,500, 32,000, and 22,200.
Plasma membrane of cultured oligodendrocytes: II. Possible structural and functional domains
Authors: Szuchet Sara , Polak Paul E. , Yim Sung Hye , Lange Yvonne 
Published: January 2005

AbstractAn oligodendrocyte plasma membrane‐rich fraction, F2.2, was resolved by equilibrium density centrifugation on a linear sucrose gradient from 0.5 M to 1.3 M into three fractions, F2.2a, F.2.2b, F2.2c, and a pellet F2.2p. F2.2a and F.2.2b were enriched 1.5‐fold relative to F2.2 in plasma membrane markers at the expense of F2.2c and F2.2p, which became correspondingly impoverished. This gave F2.2a and F2.2b a 42‐fold and 37‐fold enrichment, respectively, in plasma membrane markers relative to the initial cell homogenate. F2.2c had a sevenfold enrichment in a Golgi marker; together with F2.2p, they contained all the Golgi marker initially present in F2.2. Preliminary data indicated that the F2.2‐subfractions differed from one another in their molar ratios of cholesterol to phospholipids and protein to lipids but had similar protein profiles when examined by sodium dodecylsulfate‐polyacrylamide gel electrophoresis. Their content of fucosylated glycoproteins appeared also to be different. Morphologically, F2.2a and F2.2b were very similar: they contained large membrane vesicles, membrane sheets, and vesicles entrapped within other vesicles. Membrane‐membrane interaction was apparent in these fractions. F2.2c had many of the same elements, but most of the membrane structures contained amorphous material. F2.2p differed morphologically from the other fractions in that it had principally electron‐dense structures. It is postulated that F2.2a, F2.2b, and perhaps F2.2c represent different domains of oligodendrocyte plasma membrane. Alternatively, these fractions might correspond to the plasma membrane of oligodendrocyte subtypes.
Direct effects of carbachol on membrane potential and ion activities in leech glial cells
Authors: Ballanyi K. , Schlue W.‐R. 
Published: January 2005

AbstractIon‐selective double‐barreled microelectrodes were used to measure the activities of intracellular K+ and Na+ (a, a) and the membrane potential (Em) in neuropile glial cells as well as extracellular K+ (a) in the neuropile of segmental ganglia in the leech, Hirudo medicinalis. Bath‐application of carbachol resulted in a prominent membrane depolarization. This depolarization was accompanied by transient increases of a and a, whereas a decreased. It is suggested that the carbachol‐induced depolarization and the underlying ion activity changes are due to activation of an acetylcholine receptor‐coupled cation channel in the membrane of the neuropile glial cells.
Swelling of astrocytes causes membrane potential depolarization
Authors: Kimelberg H. K. , O'Connor E. 
Published: January 2005

AbstractRat brain astrocytes growing in primary monolayer cultures were swollen by exposing them to media of decreasing osmolality caused by removal of NaCl, and the effects of this treatment on their membrane potentials were measured by intracellular recording. Depolarizations were seen that were proportional to the degree of swelling, reaching a maximum of around 60 mV when 80–100 mM NaCl was removed from the reaction media, which had an original total osmolality of 290 mosmolal. These effects were completely reversible, since restoring the cells to iso‐osmotic medium after a 2‐min exposure caused an immediate repolarization back to the original membrane potentials, and depolarizations were not seen when isotonicity was maintained by replacing NaCl with sucrose. Partial repolarization was seen during an extended period (30 min) of exposure to hypo‐osmotic medium, mirroring a regulatory volume decrease we have previously described in these cells under identical conditions. In ion‐replacement studies depolarizatins were seen when the solution was made hypo‐osmotic with the large cation N‐methyl‐D‐glucamine totally replacing Na+ in the medium. Removal of Cl− from the medium also had no effect on the initial swelling‐induced depolarization. These results show that even moderate swelling of astrocytes in primary culture results in marked depolarization of their membrane potentials; possible mechanisms for this effect and the potentially profound implications for the swelling of astrocytes seen in situ under pathological conditions are discussed.
Glial conditioned medium enables jimpy oligodendrocytes to express properties of normal oligodendrocytes: Production of myelin antigens and membranes
Authors: Bartlett William P. , Knapp Pamela E. , Skoff Robert P. 
Published: January 2005

AbstractCultures of cerebral cells from 2‐day‐old jimpy (jp) and normal animals were immunocytochemically stained with antibodies to galactocerebroside, 2′, 3′‐cyclic nucleotide 3′‐phosphohydrolase and proteolipid protein (PLP). As the normal cultures mature, oligodendrocytes express these markers in cell bodies, in processes and in expansive membrane sheets produced along the lengths of cell processes. In contrast, oligodendrocytes from jp cultures do not produce large membrane sheets and their total numbers are reduced. Only rarely do jp oligodendrocytes exhibit immunostaining for PLP. Thus, jp oligodendrocytes grown in vitro mimic deficiencies of jp CNS in situ. In order to examine the effect of environment and cell‐cell interactions on expression of the jp mutation we grew jp cerebral cells in the presence of medium conditioned for short periods by normal cerebral cells. Under these conditions jp oligodendroglia appeared nearly normal by immunostaining criteria. Their numbers were increased; they were able to produce and maintain membrane sheets; and some cells expressed PLP. These results show that jp oligodendrocytes have the capacity to express certain normal phenotypic parameters, and when given an appropriate environment they do so. The effects of normal conditioned medium may be due to a secreted factor, possibly produced by the astrocytes, which constitute the vast majority of cells in the conditioning cultures. The dramatic effect of normal glial conditioned medium on jp oligodendrocytes suggests that the steps leading to hypomyelination in jp are exceedingly complex and may involve glial‐glial interactions.