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Biomedical subjects

C L Moore

Publications and source records attributed to C L Moore.

At least 73 records · Page 4Linked to original sources

Contribution of nesting experience to progesterone-induced incubation in ring doves (Streptopelia risoria).

Injections of progesterone induce incubation behavior in gonadally intact ring doves only if the doves have had previous experience with at least the nest-building phase of a breeding cycle. The present study was designed to determine whether exposure to progesterone during the nest-building phase is sufficient to account for the ability of progesterone to induce incubation at a later time or whether some other factor provided by experience with this phase of the cycle is needed. Six groups of 10 pairs of doves each were provided with different combinations of experience and progesterone priming. Progesterone priming combined with social isolation or with courtship experience had no significant effect on subsequent progesterone-induced incubation. However, doves that participated in the nesting phase of the cycle during progesterone priming later incubated in response to progesterone treatment. Nesting activity, which may or may not include building the nest, seemed to be the relevant experience.

Animals↗

Sex differences in urinary odors produced by young laboratory rats (Rattus norvegicus).

Responses of adult female rats to male and female pup urine were examined in three experiments. Investigatory sniffing of male and female pup urine deposits by maternal rats was compared in a series of simultaneous choice tests given at 3-day intervals between Day 2 and Day 17 postpartum. Male urine was consistently preferred. Introduction of male, but not female, pup urine to the nest was also found to significantly elevate maternal licking of anogenital regions of pups. Thus, urine from pups of various ages contains sex-identifying odors that differentially elicit spontaneous maternal interest. The odor of male urine may provide a sufficient stimulus to account for the greater anogenital licking that males of this species normally receive. Nonmaternal, naive, adult females behaved like maternal rats, preferring male urine in the choice test. This indicates that the maternal condition of a dam is not necessary either for the olfactory discrimination or for the male odor preference.

Animals↗

Contribution of self-grooming to onset of puberty in male rats.

Self-grooming was observed to increase during the prepubertal period of Long-Evans rats. Males were significantly more likely than females to engage in genital grooming during this period. To determine whether self-grooming contributes to the onset of puberty, males were fitted with collars that either prevented or allowed self-grooming of hindquarters or were left uncollared from 27 to 48 or 55 days of age when autopsied to determine weight of accessory organs. Ventral, dorsal, and lateral prostates and seminal vesicles were significantly lighter in those rats wearing collars that prevented self-grooming. It was concluded that self-grooming, probably of the genitals, contributes to accessory organ growth in males of this species.

Age Factors↗

Maternal contributions to the development of masculine sexual behavior in laboratory rats.

Maternal licking was manipulated by lining the nasal passages of rat dams with polyethylene tubing to interfere with their olfactory competence. Olfactory cues from pups elicit maternal licking and handling, particularly of anogenital regions, and dams with olfactory deficits were observed to lick their pups less. Mature male and female offspring of these dams and their controls were gonadectomized, treated with testosterone propionate, and tested for masculine sexual behavior. The male offspring of dams that provided less maternal licking had longer ejaculatory latencies, longer post-ejaculatory intromission latencies, and longer inter-intromission intervals than controls. Female offspring of the intubed dams performed fewer mounts and intromissions, had longer intromission latencies, and longer inter-intromission intervals. It was concluded that stimulation from maternal licking contributes toward the development of a mechanism that underlies the timing of copulatory rate.

Animals↗

Site-specific polyadenylation in a cell-free reaction.

A soluble HeLa cell extract accurately polyadenylates RNA transcribed from DNA templates containing the adenovirus L3 polyadenylation site. Regardless of the length of these DNA templates, the major polyadenylated species had 3' termini corresponding to the in vivo site. Polyadenylated RNA appears after an hour lag and only reaches maximum levels after 4 hr of incubation, a time course similar to that of splicing in this extract. Inhibitor studies suggest that the polyadenylation reaction is not coupled to active transcription. Unlike splicing in this extract where exogenous substrate is processed, addition of purified RNA precursor to the reaction does not yield product polyadenylated at L3 but rather results in addition of poly (A) to termini of the precursor. This suggests that part of the specificity of polyadenylation is established by in situ synthesis of RNA. Surprisingly, synthesis of accurately polyadenylated RNA may involve small nuclear ribonucleoprotein particles (snRNPs). The reaction is inhibited by antisera of Sm and U1 RNP specificities as well as antiserum to the nuclear antigen La, but is not inhibited by control serum and anti-(U2)RNP serum.

Cell-Free System↗

The importance of immunologic factors in the pathogenesis of encephalomyocarditis virus induced diabetes in mice.

The pathogenesis of EMC virus induced diabetes has generally been thought to be caused by direct cytopathic effect of the virus on beta cells with susceptibility or resistance dictated primarily by the density of viral receptors on the beta cells of different individuals. The histological finding of insulitis, our demonstration of a protective effect of immunosuppression with ALS or anti-theta antibody and silica supports host immune factors as important determinants of susceptibility. A critical role of the immune system might be mediated by autoimmune destruction of EMC-virus infected beta cells. In susceptible strain mice treated with low dose cyclophosphamide to deplete suppressor cells, which may halt the autoimmune process and allow recovery, a prolonged period of hyperglycemia was demonstrated as compared to controls. Bone marrow exchanged between susceptible and resistant strains was also found to alter susceptibility. "B mice", deficient in T lymphocytes, when infected with EMC virus had a decreased incidence of diabetes. Susceptibility to EMC diabetes may be dictated by the autoaggressive response of host immune system to beta cells altered by EMC virus infection.

Animals↗

Synergistic effect of AMP and fructose 2,6-bisphosphate on the protection of fructose 1,6-bisphosphatase against inactivation by trypsin.

The rate of inactivation of chicken liver fructose 1,6-bisphosphatase by trypsin is reduced if the digestive reaction is conducted in the presence of AMP or fructose 2,6-bisphosphate. The effects of these 2 compounds are synergistic. Although fructose 1,6-bisphosphate does not protect the enzyme against tryptic inactivation, it can enhance the effect of AMP. Selective modification of the AMP allosteric site of fructose 1,6-bisphosphatase with pyridoxal-P and NaBH4 renders the enzyme more resistant to tryptic inactivation, but the modified enzyme is no longer responsive to the protective effect of AMP.

Adenosine Monophosphate↗

Gyrase . DNA complexes visualized as looped structures by electron microscopy.

Gyrase bound to duplex DNA in the absence of ATP is seen by electron microscopy as a nearly spherical particle frequently located at the intersection of two duplex DNA strands. Such looped structures with gyrase situated at the base of the loops are observed with both linear and circular DNA substrates, and two or three individual DNA molecules bound to the same protein are also seen at high DNA concentrations. Addition of the nonhydrolyzable beta,gamma-imido analog of ATP to the gyrase . DNA reaction mixture prior to sample fixation for microscopy reduces the frequency of gyrase molecules found at DNA intersections. Looped structures similar to those of the gyrase . DNA complex are also seen with the complex of DNA and the A subunit of gyrase. When negatively supercoiled DNA which has been partially relaxed by gyrase in the absence of ATP is fixed for electron microscopic examination, intermediate forms are observed that contain both supercoiled and relaxed loops in a single DNA molecule, with the enzyme located at the common base of the loops. These results suggest that gyrase possesses multiple DNA-binding sites, a feature which allows the enzyme to hold DNA in constrained loops. The relation of these observations to the mechanism of gyrase action is discussed.

Base Composition↗

An observation about myelination.

An analysis of the direction of myelination of fibers in the optic tract of a kitten shows that the direction of wrapping of neighboring fibers is not random. Adjacent fibers in contact with the same glial process tend to be wrapped in the same direction. A model for myelination is proposed to account for this observation.

Animals↗

Maternal behavior of rats is affected by hormonal condition of pups.

Previous research has found that maternal rats discriminate male from female offspring and provide more anogenital licking to males. Two experiments were performed to determine whether this discrimination is based on hormonal condition of young. It was found that 500 micrograms of testosterone, estradiol, or dihydrotestosterone injected on the day of birth into female pups led to their receiving an equivalent amount of maternal anogenital licking as males and significantly more than either oil or untreated females. The different steroids had similar effects. Maternal nonanogenital licking was not affected by sex or hormonal condition of pups, but it was significantly increased by injection per se. Effects on maternal behavior of hormonal condition or neonatal injection of young were apparent 1 and 9 days after injection.

Animals↗

Filamentous structures associated with Epstein-Barr virus-infected cells.

After the onset of Epstein-Barr virus DNA and protein synthesis 10 h after superinfection of Raji cells (a cell line containing Epstein-Barr virus DNA but not producing virus), filamentous structures 25 nm in diameter and 0.2 to 1.4 micrometers in length could be detected in the cell cytoplasm by electron microscopy. These structures banded in metrizamide gradients with viral DNA and proteins, but at a density different from that of virions or nucleocapsids. These filaments, enriched in a 155,000-dalton protein similar in size to a major nucleocapsid protein of Epstein-Barr virus, may represent intermediates in viral nucleocapsid assembly.

Acyclovir↗

The performance of neurologically impaired and normal Ss on four screening techniques.

Administered four screening instruments--Peabody Picture Vocabulary Test-Form A (PPVT-A), Riley Preschool Developmental Screening Inventory-Designs (RPDD), Riley Make-A-Boy (RMB) and the McCarthy Scales of Children's Ability Designs (MSCD)--to 23 normal children with no evidence of neurological impairment and 23 neurologically impaired children under 6 years of age. The children were matched for age and sex and were from a day-care program for working parents and a therapeutic preschool program, respectively. Significant differences were found between the two groups on all instruments. The highest positive correlation for the impaired group was between the PPVT-A and the RPDD, while for the control group the highest positive correlation was between the RPDD and MSCD.

Brain Diseases↗

Does a defect of energy metabolism in the nerve fiber underlie axonal degeneration in polyneuropathies?

A number of chemically unrelated neurotoxic compounds and several types of metabolic abnormalities cause strikingly similar patterns of distal symmetrical polyneuropathy in humans and animals. Experimental studies with laboratory species have demonstrated that many toxic polyneuropathies are associated with distal and retrograde axonal degeneration occurring in vulnerable nerve fiber tracts in the central as well as the peripheral nervous system. This has been termed central-peripheral distal axonopathy. Recent observations from the authors' laboratories regarding (1) the spatial-temporal evolution of nerve fiber degeneration in experimental toxic neuropathies and (2) the inhibition of glycolytic enzymes by chemically unrelated neurotoxic compounds point to a common metabolic basis for many distal axonopathies. It is postulated that neurotoxic compounds deplete energy supplies in the axon by inhibiting nerve fiber enzymes required for the maintenance of energy synthesis. Resupply of enzymes from the neuronal soma fails to meet the increased demand for enzyme replacement in the axon, causing the concentration of enzymes to drop in distal regions. This leads to a local blockade of energy-dependent axonal transport, which produces a series of pathological changes culminating in distal nerve fiber degeneration. The idea provides a working hypothesis with which to study the cause of inherited and acquired human and animal polyneuropathies.

Axonal Transport↗

Mother rats interact differently with male and female offspring.

Lactating Long-Evans rats were observed to interact differently with male and female pups during the first 18 days postpartum. Differences in the mother's behavior were related to the gender composition of her litter (GHL), to the sex of a single introduced pup, and to the sex of individual pups within her litter. Major differences were the greater time spent in licking the anogenital region of own male pups and the greater stimulation of anogenital licking by male foster pups, an effect that did not interact with GHL or age of pup. The GHL interacted with day of testing to affect nest building and time spent near pups.

Animals↗