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Biomedical subjects

R W Bell

Publications and source records attributed to R W Bell.

At least 19 recordsLinked to original sources
PubMed1978

Neonatal ultrasounds elicited by odor cues.

Ultrasounds were monitored from neonatal rats following placement on 1 of 5 types of bedding material. Odors associated with the home cage or an adult male inhibited neonatal ultrasonic signaling. Odors associated with a novel lactating female elicited initially high rates of signaling, the rate lowering across the age range of pups tested. Odors associated with a novel virgin female or with an absence of animal odors elicited increasing rates of signaling across the age range tested.

Age Factors↗
PubMed1978

Effects of differential early experience upon parental behavior in Mus musculus.

Infant mice, reared with both parents were subjected to 1 of 4 different early experience contingencies at 3, 6, 9, and 12 days of age. Observation of parental behaviors following return of the pups to the nest revealed that mothers attended more to pups subjected to intermediate levels of stress, with the differences in maternal behavior persisting across the age span without change. Fathers exhibited marked changes in responsiveness to young across the ages observed, with their attention to young correlating directly with rate of ultrasonic calling by the young.

Age Factors↗
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↗
PubMed1977

Maternal behavior: a determinant of amphetamine toxicity in rats.

At 130 days of age, 31 female rats that had been subjected in infancy to handling, mother-separation, both, or neither, were injected with d-amphetamine (100 mg/kg, 50 mg/ml, i.p.). The subjects form handled, mother-present litters were the only group that showed increased latency to death. This finding indicated that the maternal behavior elicited by early handling, rather than early handling or maternal presence alone, resulted in reduced amphetamine toxicity in the offspring, tested in adulthood.

Animals↗
PubMed1977

Effect of handling on maternal behavior following return of pups to the nest.

Handling rat pups during the 1st week after birth altered adult behavior in the open-field, whereas simply spearating the pups from their mothers during the same period produced differences in body weight at weaning. Observations of mother-infant interaction following pup treatment yielded different patterns of maternal behavior. Moreover, pups receiving early treatment were more active as adults in a novel environment and had a greater body weight at weaning. The quality of maternal care and the immediate effects of infantile stimulation on the mother-infant relation should be considered in specifying a mediating mechanism for the effects of early experience.

Age Factors↗
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↗
PubMed1977

Maternally determined susceptibility to D-amphetamine-induced stereotypy in rats.

During the first week after parturition, rat pups were removed and returned to a mother-present nest, were removed and returned to a mother-absent nest, were separated from their mothers by removal of the mothers, or were undisturbed. In adulthood when repeatedly injected with a dose of D-amphetamine which induces progressively higher levels of stereotypy (2.5 mg/kg), only subjects which had been removed and returned to a mother-present nest in infancy showed a retarded rate of increase in stereotypy.

Animals↗
PubMed1976

The influence of early auditory experience on later auditory and tactual variation seeking in the rat.

Albino rats were raised under 1 of 4 conditions of auditory stimulation from 22-35 days of age. At 40 days, preferences for auditory and tactual variation were assessed in separate runway tests. Results were analyzed in a split-plot design for each of 2 measures of variation seeking. Subjects experiencing more-variable early stimulation scored higher than subjects receiving less-variable stimulation on 1 measure of variation-seeking and lower on the 2nd measure. The effect was intermodal since these results were obtained for tactual as well as auditory variation seeking.

Acoustic Stimulation↗
PubMed1975

Experimental unconfounding of age and maternal responsiveness in rodents: prenatal CER conditioning to neonatal ultrasounds.

Prior to mating, virgin female Long-Evans Rattus norvegicus received 30 classical CER trials with shock as the UCS and either taped neonatal ultrasounds or a belltone as the CS. Additional animals were placed in groups controlling for exposure to shock, the ultrasounds, the belltone, and placement in the conditioning apparatus. Following mating and parturition mother-infant observations revealed that those mothers previously conditioned to neonatal ultrasounds spent more time in the lactation posture than did mothers from the other groups. The results suggest that naive mothers can be "primed" to exhibit greater maternal responsiveness than is characteristic of primiparous mothers.

Age Factors↗
PubMed1975

The ontogeny of ultrasounds in two strains of Rattus norvegicus.

The developmental course of ultrasonic signaling by neonatal rat pups (Rattus norvegicus) was monitored under varying degrees of hypothermic stress. Signal rate, peak frequency, duration, and complexity of signals were analyzed separately for two different laboratory stocks. Sprague-Dawley and Wistar/Furth. Additionally, preliminary data were obtained on maternal retrieval latencies during the 1st 4 days post-partum and compared with the emission rate of neonatal ultrasounds. On the basis of these and other data, there is evidence that mothers play an important role in mediating many early experience effects. The data suggests that rate of neonatal ultrasounds may provide an index of some aspects of rat of maturity; that there may be different periods of maximum sensitivity to external stimulation in various stocks of laboratory animals; and that differential maternal responsiveness in different stocks of laboratory animals may correlate with differences in neonatal ultrasonic calling. Implications for comparative, genetic, and developmental studies are discussed.

Age Factors↗
PubMed1975

Ophthalmologic findings in malaria.

During the Vietnamese conflict, malaria in epidemic proportions constituted a serious health hazard to our forces. Although rarely encountered worldwide, Falciparum malaria proved to be an extremely lethal and dangerous complicating factor. Ophthalmologic complications of malaria are discussed and particular attention is placed on Falciparum malaria with the report of a case in detail and the presentation of unusual fundus findings.

Adult↗