| isospora peromysci davis, 1967 (apicomplexa: eimeriidae) in peromyscus leucopus and p. maniculatus (rodentia: cricetidae) from texas. | oocysts of isospora peromysci (davis, 1967) (apicomplexa: eimeriidae) were recovered from the feces of 1/30 (3.3%) white-footed mice, peromyscus leucopus, in johnson county, texas. this report represents a new host and geographic record for the parasite. the coccidium was also found in 1/20 (5.0%) deer mice, p. maniculatus, from the same locale. morphological data are provided on the sporulated oocyst of i. peromysci and comparisons are made with previously published information on the species f ... | 1989 | 2724183 |
| habitat distribution of ixodes dammini (acari: ixodidae) an lyme disease spirochetes on fire island, new york. | the distributions of ixodes dammini spielman, clifford, piesman, and corwin and lyme disease spirochetes were studied on fire island, n.y. adult ticks were more common in high-shrub habitats (shrubby vegetation greater than or equal to 1 m high) than in grassy and lowshrub habitats (vegetation less than 1 m) in spring and fall. in the fall, adults were also common in the woods. adults were more abundant on narrow trails than in nearby vegetation. during the summer, questing nymphs and larvae wer ... | 1989 | 2724316 |
| ear punch biopsy method for detection and isolation of borrelia burgdorferi from rodents. | an ear punch biopsy method for the detection and isolation of borrelia burgdorferi from rodents was developed. the ear punch biopsy proved to be extremely sensitive, detecting spirochetes in 100% (11 of 11) of laboratory hamsters infected by tick bite and 95.8% (23 of 24) of hamsters infected by intraperitoneal inoculation. when cultured at 4 to 6 weeks postinfection, 92 to 100% of the ear punches taken from individual hamsters yielded viable spirochetes. b. burgdorferi was detected in sequentia ... | 1989 | 2768461 |
| comparing the relative potential of rodents as reservoirs of the lyme disease spirochete (borrelia burgdorferi). | the authors compared the contribution of white-footed mice (peromyscus leucopus), chipmunks (tamias striatus), and meadow voles (microtus pennsylvanicus) to infection of vector ticks with the lyme disease spirochete, borrelia burgddorferi. at one massachusetts location where lyme disease is endemic, all three species of rodents were found to be infected. prevalence of infection, however, varied from 90% for mice, and 75% for chipmunks to just 5.5% for meadow voles. infectivity of these hosts for ... | 1989 | 2787105 |
| host genetics as a cause of overdispersion of parasites among hosts: how general a phenomenon? | in the white-footed mouse, peromyscus leucopus, the tapeworm hymenolepis citelli occurs at low (2-3%) prevalence in the field. we found that mature infections (i.e., with egg production) developed in up to 100% of hosts. in the laboratory, a majority of hosts lost their infection by 28 days postintubation. in wild mice infected in the laboratory and returned to the field, infections were more prolonged, with half of the mice still infected at 100 days postintubation. a majority of previously inf ... | 1989 | 2795375 |
| antibody response in white-footed mice (peromyscus leucopus) experimentally infected with the lyme disease spirochete (borrelia burgdorferi). | white-footed mice (peromyscus leucopus), the primary reservoir for borrelia burgdorferi in the northern midwest and northeastern united states, were experimentally inoculated with an infectious strain or a noninfectious strain of the lyme disease spirochete and examined for their specific antibody response with the enzyme-linked immunosorbent assay and western blot (immunoblot) analysis. immunoglobulin m (igm) anti-b. burgdorferi antibodies were detected in mice 1 to 2 days after inoculation wit ... | 1989 | 2807530 |
| mys retrotransposons in peromyscus leucopus and transgenic mus musculus. | the mys family of retrotransposons exhibits an interesting phylogenetic distribution with 500-1000 copies per haploid genome in the white-footed mouse peromyscus leucopus and no copies detectable in the house mouse mus musculus, even though most other repeated sequences are shared by these two species. comparison of the dna sequences from the 3' ends of five mys elements show that insertion occurs just upstream of a well-conserved 11 bp target sequence. transcription patterns of the elements in ... | 1988 | 2836794 |
| melatonin does not affect in vitro secretion of testosterone in white-footed mouse testis. | there is evidence that melatonin may exert its antigonadal effect by acting in the gonad to inhibit steroidogenesis. to explore this possibility a hormonally sensitive in vitro system of dispersed peromyscus leucopus testis was used to assess the effects of melatonin on human chorionic gonadotropin (hcg)- and dibutyryl-camp (dbcamp)-stimulated secretion of testosterone (t). at near-maximally stimulating doses of hcg and dbcamp, melatonin in concentrations of 2 x 10(-12) m to 2 x 10(-7) m did not ... | 1988 | 2852242 |
| prospective seroepidemiology of hantaviruses and population dynamics of small mammal communities of baltimore, maryland. | we used a prospective seroepidemiological study, in conjunction with a mark-release-recapture protocol, to investigate the transmission of hantaviruses in four rodent species from baltimore, maryland, from june 1984 to june 1986. a total of 1,208 captures of 762 rodents provided 984 individual blood samples. the antibody prevalence, as determined by frequency of reciprocal indirect fluorescent antibody (ifa) titers greater than or equal to 32, was 33.9% in rats (rattus norvegicus, n = 466), 28.3 ... | 1987 | 2891308 |
| photoperiodic adjustments in hypothalamic amines, gonadotropin-releasing hormone, and beta-endorphin in the white-footed mouse. | this study was undertaken to examine short photoperiod (sd; 8 h of light, 16 h of darkness)-induced alterations in reproductive endocrine and neuroendocrine parameters in the male white-footed mouse, peromyscus leucopus. exposure to sd for 8 weeks caused dramatic reductions in testis and seminal vesicle weights, decreased circulating lh and testosterone levels, and lowered the content of lh in the pituitary gland relative to those in mice under long photoperiod (ld; 16 h of light, 8 h of darknes ... | 1988 | 2899500 |
| incompetence of catbirds as reservoirs for the lyme disease spirochete (borrelia burgdorferi). | we compared the relative infectivity to vector ticks of gray catbirds (dumetella carolinensis) and white-footed mice (peromyscus leucopus) for the lyme disease spirochete (borrelia burgdorferi). of 28 catbirds captured in a site enzootic for this agent, 18 were infested by immature ixodes dammini, the tick vector. by comparison, each of 32 mice sampled concurrently from the same site was infested, and by about 10 times as many ticks as were found infesting the 3 most commonly netted bird species ... | 1989 | 2918445 |
| melatonin acts in the brain to mediate seasonal steroid inhibition of luteinizing hormone secretion in the white-footed mouse (peromyscus leucopus). | a melatonin-induced supersensitivity of the gonadotropin-secretory system to the negative feedback action of sex steroids is thought to be important to the timing of seasonal reproduction. however, little is known concerning this action of melatonin. in the present study the antigonadal action of melatonin in the anterior hypothalamus (ah) of the white-footed mouse, peromyscus leucopus, was used to examine the neuroendocrine mechanism whereby melatonin enhances the sensitivity to sex steroid neg ... | 1988 | 2969112 |
| effects of photoperiod, beta-endorphin, and naloxone on in vitro secretion of testosterone in white-footed mouse (peromyscus leucopus) testes. | the effects of the pro-opiomelanocortin-derived beta-endorphin (b-ep) and the opioid antagonist naloxone on in vitro secretion (accumulation of testosterone (t) in the medium) of t by testicular cells were assessed in adult white-footed mice (peromyscus leucopus). animals were housed under long days (16l:8d) to maintain testicular function or under short days (8l:16d) to induce gonadal regression. in vitro treatment with b-ep or naloxone did not affect basal secretion of t in dispersed cells fro ... | 1988 | 2974731 |
| mys, a family of mammalian transposable elements isolated by phylogenetic screening. | it has recently been demonstrated both emperically and mathematically that transposable elements may spread rapidly throughout a population once introduced even when they dramatically reduce the fitness of individuals that carry them. such events result in pronounced differences in the phylogenetic distribution of genetic elements capable of rapid genome invasion. using a simple and general procedure to screen the genome of the white-footed mouse peromyscus leucopus, we have isolated a family of ... | 1985 | 2993916 |
| effects of chronic polychlorinated biphenyls exposure on reproductive success of white-footed mice (peromyscus leucopus). | | 1987 | 3111392 |
| effects of chronic polychlorinated biphenyls exposure on growth and reproduction of second generation white-footed mice (peromyscus leucopus). | | 1988 | 3122670 |
| brief exposure to a natural predator, the short-tailed weasel, induces benzodiazepine-sensitive analgesia in white-footed mice. | exposure to a natural predator, the short-tailed weasel, mustela erminea, elicited significant increases in the nociceptive responses of wild male white-footed mice, peromyscus leucopus. a short (30 sec), ecologically relevant, nonvisual exposure to a weasel elicited a relatively brief (15 min) analgesia that was insensitive to the opiate antagonist, naloxone (1.0 mg/kg), and was blocked by either pre- or post-exposure injections of the benzodiazepine antagonist, ro15-1788 (10 mg/kg), or agonist ... | 1988 | 3145512 |
| ticks and biting insects infected with the etiologic agent of lyme disease, borrelia burgdorferi. | members of 18 species of ticks, mosquitoes, horse flies, and deer flies were collected in southeastern connecticut and tested by indirect fluorescent-antibody staining methods for borrelia burgdorferi, the etiologic agent of lyme disease. an infection rate of 36.2% (116 tested), recorded for immature ixodes dammini, exceeded positivity values for all other arthropod species. prevalence of infection for hematophagous insects ranged from 2.9% of 105 hybomitra lasiophthalma to 14.3% of seven hybomi ... | 1988 | 3170711 |
| new borrelia burgdorferi antigenic variant isolated from ixodes dammini from upstate new york. | a previously undescribed borrelia burgdorferi antigenic variant was isolated from each of four ixodes dammini larvae removed from white-footed mice, peromyscus leucopus, captured in millbrook, n.y. this site is in the northern range of the known distribution of the tick in the northeastern united states. the molecular weights of approximately 32,500 and 35,500 for outer surface a and outer surface b proteins, respectively, were distinctly higher than those for previously characterized isolates f ... | 1988 | 3183008 |
| borrelia burgdorferi infection surrounding la crosse, wis. | this investigation defined the extent of borrelia burgdorferi infection surrounding la crosse, wis. white-footed mice, peromyscus leucopus or p. maniculatis, were captured from sites in wisconsin, minnesota, and iowa and cultured for b. burgdorferi to define the local boundaries of the midwestern lyme disease area. all foci of b. burgdorferi infection (n1, n2, n3, and n4) were located north of interstate highway 90 except focus s2, which was south of the highway near fort mccoy, wis. the interst ... | 1988 | 3230137 |
| the urinary bladder, a consistent source of borrelia burgdorferi in experimentally infected white-footed mice (peromyscus leucopus). | white-footed mice, peromyscus leucopus, were experimentally infected in the laboratory with borrelia burgdorferi, the causative agent of lyme disease. after mice were infected by intraperitoneal or subcutaneous inoculation or by tick bite, attempts were made to culture spirochetes from the urinary bladder, spleen, kidney, blood, and urine. spirochetes were most frequently isolated from the bladder (94%), followed by the kidney (75%), spleen (61%), and blood (13%). no spirochetes were isolated fr ... | 1988 | 3290239 |
| a brain site for the antigonadal action of melatonin in the white-footed mouse (peromyscus leucopus): involvement of the immunoreactive gnrh neuronal system. | quantitative assessment of immunocytochemical staining for gonadotropin-releasing hormone (gnrh) was undertaken to determine the effects of an intracranial implant of melatonin on the gnrh neuronal system in the male white-footed mouse (peromyscus leucopus). melatonin-containing pellets stereotaxically placed in the anterior hypothalamic area (ah) caused a 60% reduction in testes weight relative to control mice with melatonin-free pellets in the ah (p less than 0.01). subcutaneous melatonin-cont ... | 1987 | 3302747 |
| new infectious spirochete isolated from short-tailed shrews and white-footed mice. | a spirochete with two periplasmic flagella was isolated from the blood or tissues of spleens and kidneys from short-tailed shrews (blarina brevicauda) and white-footed mice (peromyscus leucopus) in connecticut and minnesota. after inoculation, the shrew-mouse spirochete infected swiss mice and syrian hamsters. this spirochete is morphologically and serologically distinct from the species of treponema, borrelia, leptospira, and spirochaeta examined. | 1987 | 3305565 |
| prevalence of borrelia burgdorferi in white-footed mice and ixodes dammini at fort mccoy, wis. | borrelia burgdorferi, the causative agent of lyme disease, was isolated from 15 of 17 white-footed mice (peromyscus leucopus) and 54 of 82 subadult ixodes dammini from fort mccoy, wis. of the 47 isolates tested, all reacted in indirect fluorescent-antibody tests with monoclonal antibodies directed against a surface protein of b. burgdorferi (approximate molecular weight, 31,000) and flagellins that are common to all borrelia species. indirect fluorescent-antibody reactions were variable when an ... | 1987 | 3305566 |
| chromosomal aberrations in native small mammals (peromyscus leucopus and sigmodon hispidus) at a petrochemical waste disposal site: i. standard karyology. | | 1987 | 3314736 |
| learning in mature mice (peromyscus leucopus) subjected to deep hypothermia as neonates. | in certain species of nonhibernating rodents, although young nestlings cease breathing and heart action when their body temperature is lowered to near freezing, the nestlings need only be rewarmed to recover. this remarkable capacity for immediate recovery has been known many years, but long-range consequences of deep neonatal hypothermia have never before been investigated. mice (peromyscus leucopus) that had been exposed to four 2.5-hr episodes of deep (2-4 degrees c) hypothermia when 4-10 day ... | 1988 | 3365944 |
| a novel postcopulatory block of reproduction in white-footed mice. | female white-footed mice (peromyscus leucopus) fail to produce offspring when paired with a male from weaning until 150 days of age if an adult female or her odor is also present. the present study delineates more clearly which stage of the young female's reproductive cycle is inhibited by the chemosignal of the older female. age at vaginal opening and first estrus are delayed by the presence of the older female, but only for about 10 days. the presence of a male counteracts this delay. thus, th ... | 1988 | 3378075 |
| serologic analyses of peromyscus leucopus, a rodent reservoir for borrelia burgdorferi, in northeastern united states. | an enzyme-linked immunosorbent assay (elisa) and indirect fluorescent-antibody test were used to detect antibodies to borrelia burgdorferi, the causative agent of lyme disease, in peromyscus leucopus (white-footed mouse). of the 661 mice captured in connecticut, rhode island, and new york during 1980 and 1983 to 1987, 166 (25.1%) had antibodies to b. burgdorferi by elisa. comparative analyses of 210 serum specimens, collected in areas where lyme disease is endemic, revealed a threefold differenc ... | 1988 | 3384925 |
| changes in infectivity and plasmid profile of the lyme disease spirochete, borrelia burgdorferi, as a result of in vitro cultivation. | in vitro cultivation of borrelia burgdorferi, the etiologic agent of lyme spirochetosis, allows for the isolation and growth of this bacterium from infected tissues. however, continuous cultivation in modified kelly medium causes a reduction in the number of detectable plasmids and the loss of infectivity in the white-footed mouse, peromyscus leucopus. in an unpassaged culture of b. burgdorferi, nine plasmids were present, including seven linear plasmids ranging in size from 49 to 16 kilobases ( ... | 1988 | 3397175 |
| peromyscus leucopus and microtus pennsylvanicus simultaneously infected with borrelia burgdorferi and babesia microti. | borrelia burgdorferi, the etiologic agent of lyme disease, and babesia microti, the causative agent of human babesiosis, were isolated from 71 and 57%, respectively, of 14 specimens of peromyscus leucopus and microtus pennsylvanicus collected from prudence and patience islands, r.i. both pathogens were isolated from five individual rodents. the presence of these two infectious organisms in the same mammal suggests that individual larval ixodes dammini may ingest both pathogens and subsequently t ... | 1986 | 3517038 |
| gonadotropin-releasing hormone neuronal system of the white-footed mouse, peromyscus leucopus. | the cytoarchitecture of the gonadotropin-releasing hormone (gnrh) neuronal system of the female white-footed mouse (peromyscus leucopus) was characterized using immunocytochemical procedures on thick vibratome sections. most of the labelled cell bodies are organized loosely into three groups associated with the periventricular region of the medial preoptic area, the diagonal band of broca, and the olfactory peduncle. a small number of cells are scattered throughout the medial septum, retrochiasm ... | 1986 | 3523277 |
| short photoperiod-induced gonadal regression: effects on the gonadotropin-releasing hormone (gnrh) neuronal system of the white-footed mouse, peromyscus leucopus. | the peroxidase-antiperoxidase method was used to determine quantitatively the effect of short photoperiod-induced gonadal regression on the immunoreactive gonadotropin-releasing hormone (gnrh) neuronal system of female peromyscus leucopus. in mice exposed to either long (16l:8d) or short (8l:16d) photoperiod, immunoreactive cell bodies were loosely organized into six groups: olfactory peduncle, diagonal band of broca, septum, preoptic area (poa), anterior hypothalamus (ah), and basal hypothalamu ... | 1986 | 3539214 |
| immunoreactive luteinizing hormone-containing neurons in the brain of the white-footed mouse, peromyscus leucopus. | the distribution of immunoreactive lh in the brain of the white-footed mouse (peromyscus leucopus) was determined using immunocytochemical procedures. immunoreactive fibers are located in the hypothalamus, preoptic area, septum and amygdala. stained cell bodies are seen in the arcuate nucleus and preoptic area. gonadectomy enhances staining for lh in the brain. | 1987 | 3545894 |
| experimental inoculation of dogs with borrelia burgdorferi. | to determine if dogs could serve as a reservoir for borrelia burgdorferi, three beagles were inoculated subcutaneously (sq) with 200 laboratory cultured spirochetes which were originally isolated from blood of a peromyscus leucopus from ft. mccoy, wisc. one four month old beagle was inoculated sq with 5 ground ixodes dammini from shelter island, n.y. which came from an area with a 50% b. burgdorferi tick infection rate; and another uninfected four month old beagle was housed loose on the floor w ... | 1986 | 3554844 |
| lyme disease and babesiosis: acaricide focused on potentially infected ticks. | permethrin-treated cotton, intended as rodent nesting material, was distributed in wooded sites in which the agents of lyme disease and babesiosis were enzootic, in order to kill immature ixodes dammini, the ticks that transmit these human pathogens. such ticks feed most abundantly on white-footed mice (peromyscus leucopus), apparently the main reservoir hosts of these agents, and tend to concentrate in mouse burrows. mice captured after permethrin-treated cotton was distributed, were infested b ... | 1987 | 3555140 |
| prevalence of borrelia burgdorferi and babesia microti in mice on islands inhabited by white-tailed deer. | borrelia burgdorferi and babesia microti were isolated from 35 of 51 white-footed mice (peromyscus leucopus) and meadow voles (microtus pennsylvanicus) captured on two narragansett bay, r.i., islands inhabited by deer, the principal host for the adult stages of the vector tick, ixodes dammini. immature ticks parasitized mice from both islands. from 105 mice captured on four other islands not inhabited by deer neither pathogen was isolated, nor were i. dammini found. | 1987 | 3555339 |
| accelerated wound repair in old deer mice (peromyscus maniculatus) and white-footed mice (peromyscus leucopus). | the closure of bilateral full thickness cutaneous wounds, made over the back with a sharp paper punch, was measured and assessed histologically in outbred deer mice (peromyscus maniculatus) and white-footed mice (peromyscus leucopus). in contrast to inbred c57bl/6j laboratory mice (mus musculus), in which the rate of wound repair was more rapid in young than in mature or aged mice (cohen et al., 1987), wound repair in peromyscus was most rapid in aged animals. aged peromyscus (45 to 70 months) a ... | 1987 | 3571866 |
| culturing borrelia burgdorferi from spleen and kidney tissues of wild-caught white-footed mice, peromyscus leucopus. | borrelia burgdorferi was isolated most frequently from tissue of spleen (n = 13) and kidney (n = 10) and less often from blood (n = 5) of wild-caught peromyscus leucopus. prevalence of infection tended to be highest at sites where lyme disease was most common (e.g., 5 of 6 mice were positive in east haddam, connecticut). spirochetes were not isolated in danbury or new hartford, areas where this malady is rare. however, in fairfield, where the disease is also uncommon, 4 of 9 mice were infected. ... | 1986 | 3577490 |
| the prevalence and significance of borrelia burgdorferi in the urine of feral reservoir hosts. | live borrelia burgdorferi were isolated from the blood and/or urine of white-footed mice (peromyscus leucopus) collected on shelter island, new york, in 1984 and 1985. prevalence of spirochetes in urine was consistently higher than in blood or both fluids simultaneously. spirochetes remained viable for 18-24 hours in urine and were maintained in culture for one week. mice removed from the field were spirocheturic for at least 13 months. one spirocheturic mouse developed spirochetemia one month a ... | 1986 | 3577491 |
| lyme disease ecology in wisconsin: distribution and host preferences of ixodes dammini, and prevalence of antibody to borrelia burgdorferi in small mammals. | lyme disease recently has been recognized in wisconsin. trapping studies were conducted at four geographically separate and ecologically distinct regions in wisconsin to elucidate the distribution and host preferences of ixodes dammini on small and medium sized mammals, and the occurrence of antibodies to borrelia burgdorferi in these wild mammals. peak i. dammini larval activity occurred from june-september. nymphs were most active from may-august. white-footed mice (peromyscus leucopus) and ch ... | 1987 | 3605501 |
| genomic 5-methyldeoxycytidine decreases with age. | significant losses of dna 5-methyldeoxycytidine residues in old age could disrupt cellular gene expression and contribute to the physiological decline of the animal. thus, the 5-methyldeoxycytidine content of dnas, isolated from the tissues of two rodent species of various ages, were determined. mus musculus lost dna methylation sites at a rate of about 4.7 x 10(4) (approximately 0.012% of the newborn level)/month. peromyscus leucopus lost dna 5-methyldeoxycytidine residues at a rate of only 2.3 ... | 1987 | 3611071 |
| duration of the melatonin pulse in the hypothalamus controls testicular function in pinealectomized mice (peromyscus leucopus). | forty-four pinealectomized white-footed mice (peromyscus leucopus) were stereotaxically implanted with a guide tube-cannula assembly in the area of the preoptic/anterior hypothalamus. easy insertion and removal of the melatonin-loaded cannula in the basal medial hypothalamus made it possible to examine whether duration of the melatonin pulse at the putative target site controls reproduction in mice. mice receiving melatonin every day for 10 h during either the day or night underwent gonadal regr ... | 1987 | 3620557 |
| neurons in the suprachiasmatic area are labelled after intravenous injections of horseradish peroxidase. | intravenous injections of horseradish peroxidase (hrp) produced labelled neurons in the suprachiasmatic area of house mice (mus musculus), deer mice (peromyscus maniculatus bairdi), and white-footed mice (peromyscus leucopus). in the two species of peromyscus, a significant proportion of the labelled cells was found within the suprachiasmatic nucleus (scn). these results suggest that when hrp is injected in the eyes to trace retinal inputs to the hypothalamus, some of the reaction product seen i ... | 1987 | 3622673 |
| seasonal prevalence of borrelia burgdorferi in natural populations of white-footed mice, peromyscus leucopus. | borrelia burgdorferi, the etiologic agent of lyme disease, was isolated from 111 of 237 peromyscus leucopus captured during all seasons of the year. borreliae were cultured from tissues of the spleen (101 mice), left kidney (76 mice), and right kidney (73 mice), from blood (12 mice), and from one fetus. mice were infected during the winter, when immature ixodes dammini were inactive. the prevalence of infection during the winter (less than or equal to 33%) was more than twofold lower than that d ... | 1987 | 3624451 |
| effect of age and torpor on the circadian rhythms of body temperature, activity, and body weight in the mouse (peromyscus leucopus). | age-related alterations in homeostatic mechanisms, as measured by changes in circadian rhythms, have been reported in the literature. the purpose of the present study was to determine if changes in the circadian rhythms of motor activity, body temperature, and body weight occur with age in the long-lived mouse, peromyscus leucopus, and to determine if the incidence of torpor (hypothermia) was age-dependent. young and old mice were entrained to an ld 12:12 cycle, and then physiological and behavi ... | 1987 | 3628326 |
| dichlorvos toxicity in the white-footed mouse (peromyscus leucopus). | the organophosphate pesticide, dichlorvos (ddvp), is used commonly to control ectoparasites in laboratory rodents colonies. this compound is relatively nontoxic to mus musculus at dosages several times the therapeutic level. however, usage of a similar therapeutic level in the white-footed mouse (peromyscus leucopus) resulted in substantial mortality. to determine whether p. leucopus is more susceptible than m. musculus to the toxic effects of ddvp, both species were exposed to 0, 3 and 6 g of p ... | 1987 | 3669600 |
| suppression of pineal melatonin in peromyscus leucopus by different monochromatic wavelengths of visible and near-ultraviolet light (uv-a). | the purpose of this study was to examine the effects of monochromatic visible and near-ultraviolet radiation (uv-a) on pineal melatonin suppression in the white-footed mouse, peromyscus leucopus. to this end, mice were entrained to a daily cycle of 8 h of light and 16 h of darkness. during the night when pineal melatonin contents were high, mice were individually exposed for 5 min to specific wavelengths of monochromatic light (10 nm half-peak bandwidths). control animals received the same handl ... | 1987 | 3676772 |
| a comparative-evolutionary study of lipids in the aging brain of mice. | the lipids of aging brain were studied using a comparative-evolutionary model involving two species of mice, mus musculus (mus) and peromyscus leucopus (peromyscus). mus ages 2.5 times faster than does peromyscus. brain weight, water content, cholesterol, and ethanolamine plasmalogen decreased and phosphatidyl ethanolamine increased in both species with age. differences between species included 12% more cholesterol/g total lipid extract in peromyscus than in mus throughout life, a linear increas ... | 1986 | 3785533 |
| life shortening in mice exposed to fission neutrons and gamma rays. vi. studies with the white-footed mouse, peromyscus leucopus. | some of the studies on late effects of neutron and gamma radiation previously carried out with the c57bl6 x balb/c f1 hybrids of mus musculus have been repeated with the white-footed mouse, peromyscus leucopus, a cricetid rodent of a different subfamily, with differing physiological characteristics and a different spectrum of pathologies. among the more important findings were the following: for both species, the life shortening per rad at low doses of either radiation was the same percentage of ... | 1986 | 3786676 |
| reservoir competence of white-footed mice for lyme disease spirochetes. | using the vector tick, ixodes dammini, we described the reservoir competence of the white-footed mouse, peromyscus leucopus, for the lyme disease spirochete, borrelia burgdorferi. nymphal i. dammini were used to infect mammals, and larval ticks were used to diagnose infection (a form of xenodiagnosis). one tick was nearly as efficient as more than 1 in transmitting the spirochete to mice. the duration of the prepatent period was about 1 week. prevalence of infection approached 100% in ticks that ... | 1987 | 3812887 |
| identification of endemic foci of lyme disease: isolation of borrelia burgdorferi from feral rodents and ticks (dermacentor variabilis). | borrelia burgdorferi, the etiological agent of lyme disease, was isolated from the blood, kidneys, spleens, eyes, or livers of white-footed mice (peromyscus leucopus) (n = 19 of 22) and from the blood, kidneys, or spleens of eastern chipmunks (tamias striatus) (n = 2 of 2) captured at three foci for lyme disease in eastern connecticut. these bacteria were cultured most frequently from spleens (n = 19) and kidneys (n = 15). b. burgdorferi persisted in one mouse for at least 60 days. one spirochet ... | 1985 | 3926816 |
| diurnal detachment of immature deer ticks (ixodes dammini) from nocturnal hosts. | to test the possibility that immature deer ticks (ixodes dammini) may concentrate in the nests of their mouse hosts, we recorded their pattern of detachment. in laboratory experiments, most engorged larvae (greater than 90%) and nymphs (greater than 80%) detached from hamsters between 1200-2000 hours when the 14-hr photophase began at 0600 hours. time of drop-off was similar regardless of when ticks attached to hosts, but attachment late in the day delayed drop-off by one full day. ticks detache ... | 1986 | 3946736 |
| photoperiod time measurement for activity, torpor, molt and reproduction in mice. | resonance light:dark cycles (ld 6:18, 6:30, 6:42, or 6:54) were used to establish that a circadian rhythm of light sensitivity is involved in the thermoregulatory and reproductive responses to a short day photoperiod in the mouse, peromyscus leucopus. a fifth group was maintained on the long day photoperiod of ld 16:8. after 19 weeks animals presented with ld 6:18 or 6:42 exhibited short day photoperiod responses: gonadal regression, incidence of spontaneous daily torpor and molt to the winter p ... | 1986 | 3952177 |
| photoperiodic regulation of reproductive development in male white-footed mice (peromyscus leucopus) born at different phases of the breeding season. | male white-footed mice were maintained from birth in chambers equipped with latitudinal timers programmed to simulate the natural progression of daylengths at 42 degrees n latitude. mice were born into photoperiods starting on 1 april, 15 july, 15 september or 27 october. testes and seminal vesicles of april- and july-born mice were mature at 60 days of age; puberty was delayed by several months in animals born into the september and october photoperiods but these mice became fecund at about 3.5 ... | 1985 | 3968658 |
| organophosphorus insecticide induced decrease in plasma luteinizing hormone concentration in white-footed mice. | oral intubation of 50 and 100 mg/kg acephate inhibited brain acetylcholinesterase (ache) activity by 45% and 56%, and reduced basal luteinizing hormone (lh) concentration by 29% and 25% after 4 h in white-footed mice (peromyscus leucopus noveboracensis). dietary exposure to 25, 100, and 400 ppm acephate for 5 days substantially inhibited brain ache activity, but did not affect plasma lh concentration. these preliminary findings suggest that acute exposure to organophosphorus insecticides may aff ... | 1985 | 3975930 |
| temporal patterns of brain cholinesterase activities of white-footed mice (peromyscus leucopus) following dosing with diazinon or parathion. | | 1985 | 3977404 |
| mice as reservoirs of the lyme disease spirochete. | in evaluating the white-footed mouse as a reservoir host for the lyme disease spirochete, we compared spirochete infection in vector ticks (ixodes dammini) having different histories of attachment to these mice, estimated their relative importance as hosts for immature i. dammini and compared the seasonality of tick activity and spirochetemia in mice. infection in trapped white-footed mice appears to be universal. prevalence of spirochetal infection in i. dammini correlates with frequency of att ... | 1985 | 3985277 |
| effects of timed melatonin injections on reproduction in pinealectomized peromyscus leucopus. | fifty reproductively mature female pinealectomized or sham-operated white-footed mice (peromyscus leucopus) were injected daily for 7 weeks with 50 micrograms melatonin at 12 hr after lights on. the injections started either on the day following surgery or 2 weeks after surgery. all mice were maintained at room temperature under long-day photoperiod (ld 16:8). pinealectomized and sham-operated mice injected immediately following surgery and sham-operated mice injected beginning 2 weeks after sur ... | 1985 | 4007479 |
| two daily melatonin injections differentially induce nonshivering thermogenesis and gonadal regression in the mouse (peromyscus leucopus). | female white-footed mice (peromyscus leucopus) were injected twice daily with 5, 10, 50, 100 micrograms melatonin (mel) or saline. injections were given for 7 weeks at 2 and 12 hours after lights-on under a long day (ld 16:8) photoperiod. afternoon administration of mel induced gonadal regression, although a dose of 50 micrograms or more was necessary to obtain a maximal response. a 5 micrograms mel injection in the afternoon resulted in intermediate reproductive tract weights. in white-footed m ... | 1985 | 4021740 |
| pheromone-induced reproductive inhibition in young female peromyscus leucopus. | soiled bedding and urine from adult female white-footed mice (peromyscus leucopus) were tested for their capacity to inhibit reproduction of young females. test animals were given either physical or airborne contact with soiled bedding from adult females, adult female urine, clean bedding, or water from 21 to 150 days of age. results indicate that reproductive inhibition is due to an airborne pheromone emitted by the adult females as a component of their urine. in the second experiment, young fe ... | 1985 | 4041520 |
| effects of cold ambient temperatures on acute mortality of peromyscus leucopus dosed with parathion. | | 1985 | 4041648 |
| eimeria species (apicomplexa: eimeriidae) infecting peromyscus rodents in the southwestern united states and northern mexico with description of a new species. | of 198 deermice (peromyscus spp) collected from various localities in the southwestern united states and northern mexico, 106 (54%) had eimerian oocysts in their feces when examined. these included 50 of 106 (47%) peromyscus truei, 34 of 54 (63%) peromyscus maniculatus, 4 of 17 (24%) peromyscus leucopus, and 18 of 21 (86%) peromyscus eremicus. the following eimeria were identified from infected mice: eimeria arizonensis and eimeria langebarteli from p. truei; e. arizonensis, eimeria peromysci, a ... | 1985 | 4057004 |
| effect of simultaneous exposure to differences in photoperiod and temperature on the seasonal molt and reproductive system of the white-footed mouse, peromyscus leucopus. | | 1973 | 4145530 |
| seasonal spontaneous torpor in the white-footed mouse, peromyscus leucopus. | | 1973 | 4145702 |
| histological, histochemical, and cytological observations on the adrenal gland of the wild white-footed mouse, peromyscus leucopus. | | 1968 | 4178465 |
| the effect of acth, group caging, and adrenalectomy in peromyscus leucopus with emphasis on suppression of reproductive function. | | 1972 | 4336902 |
| carbonic anhydrase polymorphism in a new jersey population of the white-footed mouse peromyscus leucopus. | two electrophoretic forms of erythrocytic carbonic anhydrase were found to be controlled by one autosomal locus with two codominant alleles, ca(f) and ca(8). the gene frequencies for the ca(f) and ca(8) alleles were found to be.15 and.85, respectively, in a sample of 53 mice from middlesex county, new jersey. the observed genotypic frequencies indicated that the population was in hardy-weinberg equilibrium. | 1972 | 4625749 |
| the amount of maternal care in peromyscus leucopus and its thermal significance for the young. | | 1972 | 4654241 |
| genetic control of two esterase enzymes in peromyscus leucopus. | | 1973 | 4698912 |
| histological characterization of "epinephrine" and "norepinephrine" cells in the adrenal medulla of the white-footed mouse, peromyscus leucopus. | | 1973 | 4715234 |
| reactions of deer mice (peromyscus maniculatus) and white-footed mice (peromyscus leucopus) to homospecific and heterospecific urine odors. | | 1973 | 4737448 |
| an early unilateral thymic lymphoma in a postirradiated white-footed mouse, peromyscus leucopus. | | 1974 | 4810212 |
| relationships among three criteria of puberty in peromyscus leucopus noveboracensis. | | 1974 | 4857269 |
| techniques used in the study of the white-footed mouse under semi-natural conditions. | | 1972 | 5043485 |
| helminths from peromyscus leucopus and p. maniculatus in west virginia. | | 1971 | 5090963 |
| anaphylaxis in peromyscus leucopus mice. | | 1968 | 5239927 |
| cell proliferation in the intestinal epithelium of peromyscus leucopus after 1, 3, 10, and 35 days' exposure to 56 r-day whole-body 60co gamma irradiation. anl-7409. | | 1967 | 5308240 |
| lability of tail length of the white-footed mouse, peromyscus leucopus noveboracensis. | | 1970 | 5455373 |
| giardiosis in a wild mouse (peromyscus leucopus) colony. | | 1970 | 5465574 |
| restricted perceptual experience effects on the later avoidance behavior of two subspecies of deermice, peromyscus leucopus and peromyscus polionotus. | | 1968 | 5642540 |
| circadian activity rhythm of the deer mouse, peromyscus: effect of deuterium oxide. | chemical modification of a vertebrate activity rhythm, the circadian (approximately 24-hour) rhythm of peromyscus leucopus noveboracensis, has been demonstrated. activity in a running wheel was used to measure the rhythms of mice kept individually in conditions of continuous darkness. deuterium oxide was presented in the drinking water. the length of the periods of rhythm increased directly and linearly with the increase in concentration of deuterium oxide. there is no threshold for this effect, ... | 1968 | 5647846 |
| progeny from experimental mating tests with mice of the peromyscus leucopus group. | | 1968 | 5670806 |
| a comparison of the water balance of the forest deer mouse and the white-footed mouse. | | 1968 | 5675583 |
| unseasonal breeding in artificial colonies of peromyscus leucopus. | | 1965 | 5838228 |
| effects of cuterebra angustifrons on plasma proteins of peromyscus leucopus. | | 1965 | 5848808 |
| adrenal weight in prairie deer mice (peromyscus maniculatus bairdii) and white-footed mice (peromyscus leucopus noveboracensis). | | 1967 | 6070648 |
| modification of testicular and thyroid function by chronic exposure to short photoperiod: a comparison in four rodent species. | exposure of male syrian hamsters (mesocricetus auratus) for 10 weeks to short photoperiod (sp) providing 10 hr light: 14 hr darkness (10:14 ld) produced a significant reduction in the weights of the reproductive organs, plasma thyroxine (t4) levels and free t4 index (ft4i) compared to the values of animals exposed to long photoperiod (lp, 14:10 ld). c57bl male house mice (mus musculus) kept in sp (10:14 ld) had reproductive organ weights equivalent to those of mice kept in long days (14:10 ld) a ... | 1984 | 6146435 |
| seasonal changes in enzymes of aerobic heat production in the white-footed mouse. | during seasonal acclimatization in white-footed mice (peromyscus leucopus), there is a substantial increase in the capacity for aerobic heat production under cold stress (mmax) in winter animals. the possibility that increases in levels of enzymes involved in aerobic heat production could be responsible for the increase in mmax was investigated in mice captured in summer and winter. activities of citrate synthase (cs) and beta-hydroxyacyl-coa dehydrogenase (hoad) and concentrations of cytochrome ... | 1981 | 6263112 |
| photoperiodic regulation of reproduction in the white-footed mouse. neuroendocrine aspects. | | 1983 | 6348509 |
| an immunocytochemical study of the luteinizing hormone-releasing hormone (lhrh) system in the white-footed mouse: effect of blinding and melatonin. | previous studies have provided evidence that pineal-mediated gonadal atrophy involves the luteinizing hormone-releasing hormone (lhrh) system in some rodents. the purpose of the present study was to visualize the lhrh system in the brain of the white-footed mouse by immunocytochemical methods and to assess the influence of blinding or melatonin on the lhrh immunostaining characteristics of the median eminence. six intact adult female mice and six adult males (two intact, two blinded, and two wit ... | 1984 | 6400339 |
| comparative rates of decline in the primary cloning efficiencies of smooth muscle cells from the aging thoracic aorta of two murine species of contrasting maximum life span potentials. | primary cloning assays of thoracic aortic smooth muscle cells from an f1 hybrid strain of mus musculus demonstrated linear regressions of replicative potentials as functions of donor age (6-30 months), with regression coefficients, in two independent cohorts, of -1.69 +/- 0.27 (se) and -1.88 +/- 0.19 (se) clones per milligram wet weight of intima-media per month and correlation coefficients of -0.83 and -0.92 (p less than 0.001). secondary cloning (dilute plating from first passages) also demons ... | 1983 | 6401930 |
| relationship between field strength and arousal response in mice exposed to 60-hz electric fields. | white-footed mice, peromyscus leucopus, were exposed to 60-hz electric fields to study the relationship between field strength and three measures of the transient arousal response previously reported to occur with exposures at 100 kv/m. five groups of 12 mice each were given a series of four 1-h exposures, separated by an hour, with each group exposed at one of the following field strengths: 75, 50, 35, 25, and 10 kv/m; 8 additional mice were sham-exposed with no voltage applied to the field gen ... | 1983 | 6409124 |
| the istar 1 serodeme of trypanosoma brucei: development of a new serodeme. | an extensive serodeme of sequentially-isolated antigenic variants of african trypanosomes has been produced from both syringe-passaged and cyclically-transmitted trypanosoma brucei of the istar 1 clone derived from eatro 164. the majority of the antigenic variants were isolated from chronically-infected deer mice (peromyscus leucopus). the pattern of parasitemias during the course of infections initiated with syringe-passaged trypanosomes differed from those initiated with cyclically-transmitted ... | 1984 | 6439844 |
| longevity-dependent organ-specific accumulation of dna damage in two closely related murine species. | to measure directly the accumulation of dna damage with age, and to understand better the effect of modulators of dna damage in vivo, the dna of brain, liver, and kidney of two mice from different families, mus musculus and peromyscus leucopus, have been examined for age-dependent accumulation of single-strand breaks plus alkali-labile bonds, by the alkaline sucrose sedimentation method. these two species of small rodents are closely related taxonomically, yet differ significantly in maximum ach ... | 1984 | 6492898 |
| vectorial capacity of north american ixodes ticks. | ixodes dammini, the vector of lyme disease and babesiosis, is distributed in various locations in the northeastern quadrant of the united states and nearby canada. the life cycle of this tick, which includes larval, nymphal, and adult stages, spans at least two years. the tick over-winters between larval and nymphal feeding. horizontal transmission of pathogens is facilitated by a feeding pattern in which both the larval and nymphal stages feed on the white-footed mouse, peromyscus leucopus, and ... | 1984 | 6516453 |
| avian and mammalian hosts for spirochete-infected ticks and insects in a lyme disease focus in connecticut. | spirochetes and their vectors and reservoirs were studied in a lyme disease focus in east haddam, connecticut, from mid-may through september 1983. ixodes dammini subadults were comparable in number on white-footed mice (peromyscus leucopus) (means = 2.9 +/- 3.6 sd) to those on 27 different species of birds (means = 2.3 +/- 4.2 sd) representing 11 families within the order passeriformes. less commonly found ticks on birds (means less than or equal to 0.1) were immature ixodes dentatus and haemap ... | 1984 | 6516460 |
| prevalence of the lyme disease spirochete in populations of white-tailed deer and white-footed mice. | the prevalence of the ixodes dammini spirochete (ids) in white-tailed deer (odocoileus virginianus) and white-footed mice (peromyscus leucopus) was studied on the eastern end of long island, new york. both species commonly occur in a variety of habitats, are preferred hosts of ixodes dammini, and can harbor the spirochetes in the blood. each animal was examined for spirochetemia, tick infestation, and ids infection rates in the ticks that were removed from it. the results obtained suggest that i ... | 1984 | 6516461 |
| seasonal changes in glycogen level and size of pinealocytes of the white-footed mouse, peromyscus leucopus: a semiquantitative histochemical study. | glycogen level in and size of pinealocytes of the feral, white-footed mouse peromyscus leucopus, were studied by a semiquantitative histochemical method to determine whether seasonal changes exist in them under natural conditions, what temporal pattern they exhibit, and whether 24-hour changes in these parameters exist in different seasons, as shown in the laboratory dd-mice. marked seasonal changes were seen in both glycogen levels and nuclear densities (anova p less than 0.005). the size of pi ... | 1984 | 6545813 |
| morphological and morphometric changes in the ovaries of white-footed mice (peromyscus leucopus) following exposure to long or short photoperiod. | two experiments were carried out with a total of 36 white-footed mice (peromyscus leucopus) exposed to either long (lp) or short (sp) photoperiod for six weeks. ovaries and uteri were weighed. serial sections of the ovaries were processed for light microscopy. the total number of the interstitial gland cells, preantral and antral follicles with early and advanced stages of atresia as well as corpora lutea, was determined. uteri from lp mice weighed significantly more than those from sp mice in b ... | 1983 | 6682297 |
| effect of naltrexone on food intake and hoarding in white-footed mice (peromyscus). | increases in food consumption and hoarding in mammals have been shown to be immediate and preparative adjustments to the energetic stresses of temperate winters. the sensitivity of these behaviors to the opiate antagonist naltrexone was tested in non-deprived white-footed mice (peromyscus leucopus). mice received naltrexone hydrochloride intraperitoneally (10 mg/kg in saline vehicle) once daily for four consecutive days subsequent to an equivalent period of injection with saline as control. dail ... | 1984 | 6694998 |