| responses of sagittally aligned purkinje cells during perturbed locomotion: synchronous activation of climbing fiber inputs. | 1. these experiments were performed to test the hypothesis that climbing fiber inputs to sagittally aligned purkinje cells located in a single folium are activated synchronously in response to a perturbation of the step cycle that interrupts the trajectory of the ipsilateral forelimb. 2. the experiments were performed in acutely decerebrate ferrets capable of walking spontaneously on a moving treadmill. a multiple single-unit recording technique was employed utilizing a fixed array of five sagit ... | 1992 | 1527576 |
| emesis in ferrets following exposure to different types of radiation: a dose-response study. | ferrets were exposed to gamma rays (60co), fission neutrons, high-energy electrons (18.5 mev) or iron particles (56fe, 600 mev/amu) in order to establish the dose-response relationships for emesis following exposure to different types of radiation. the results showed that the mean effective doses (ed50s) for iron particles (35 cgy) and neutrons (40 cgy) were similar. high-energy electrons were the least effective radiation, with an ed50 of 138 cgy. gamma rays, with an ed50 of 95 cgy, showed an i ... | 1992 | 1510644 |
| pharmacology and preclinical antiemetic properties of ondansetron. | ondansetron (gr 38032) has potent and highly selective antagonist properties at the 5-hydroxytryptamine (5-ht, serotonin) 5-ht3 receptor. the selectivity ratio for ondansetron on 5-ht3 receptors compared with actions on other neurotransmitter receptor types is greater than 1,000. the antiemetic properties of ondansetron have been determined in ferrets against the nausea and vomiting induced by cisplatin, cyclophosphamide, and whole-body radiation. ondansetron (intravenous 0.01 to 0.1 mg/kg or su ... | 1992 | 1387245 |
| inhibition of cisplatin-induced emesis in ferrets by the non-nmda receptor antagonists nbqx and cnqx. | the excitatory amino acid (eaa) receptor antagonists, 2,3-dihydroxy-6-nitro-7-sulphamoylbenzo(f)quinoxaline (nbqx) and 6-cyano-7-nitroquinoxaline-2,3-dione (cnqx), which preferentially block non-n-methyl-d-aspartate (non-nmda) subtypes of eaa receptors, effectively inhibit cisplatin-induced emesis in ferrets. a high dose of cisplatin (10 mg/kg i.v.) was used which induced emesis in all saline-treated control ferrets. at 10 mg/kg i.v., nbqx totally prevented cisplatin-induced emesis in 5 of 6 fer ... | 1992 | 1350077 |
| nicotine-induced airway smooth muscle contraction: neural mechanisms involving the airway epithelium. functional and histologic studies in vitro. | to assess the mechanism of and the role of the epithelium in nicotine-induced bronchoconstriction in vitro, we performed a combined functional and histologic study. functional study: we suspended tracheal strips or rings from 16 ferrets (1124 +/- 561 g, mean +/- sd) in organ baths. alternate tracheal strips had their epithelium removed. dose-response curves to acetylcholine (ach) and nicotine were established for pairs of tissues with and without epithelium, each pair receiving only one dose of ... | 2017 | 1355677 |
| 'a new cageful of ferrets!'--medicine and the 'two cultures' debate of the 1950s. | | 1991 | 1843853 |
| triggered activity as a possible mechanism for arrhythmias in ventricular hypertrophy. | to study the cellular mechanisms of arrhythmias occurring in cardiac hypertrophy, we performed standard microelectrode studies on papillary muscles isolated from control (group n) and hypertrophied ferrets right ventricles. different stages of hypertrophy, induced by pulmonary banding, were studied: 10-22 days (group h1), 4-6 weeks (h2), and 5 1/2-6 months (h3). during the development of hypertrophy, under beta-adrenergic stimulation, triggered activity (ta) induced by delayed afterdepolarizatio ... | 1991 | 1721166 |
| reciprocal relationships between pulsatile androgen secretion and the expression of mating behavior in adult male ferrets. | the pulsatile secretion of androgen was similar over a 12-hr period in breeding male ferrets implanted with jugular catheters which either achieved an intromission with an estrous female or received no socio-sexual contact. this negative result contrasts with the previous demonstration (carroll, erskine, and baum, 1987, endocrinology 121, 1349-1359) of a significant, delayed rise in mean plasma androgen concentrations in breeding male ferrets 5-12 hr after mating. males used in that previous stu ... | 1991 | 1937429 |
| neural regulation of lysozyme secretion from tracheal submucosal glands of ferrets in vivo. | to investigate how central and peripheral nerves affect lysozyme secretion from tracheal submucosal glands in ferrets we injected substance p (20 nmol/kg in 200 microliters) intracisternally or intravenously into anesthetized artificially ventilated ferrets. we collected 3-ml samples from a perfused (3 ml/5 min) segment of trachea in situ during 15 min before and 45 min after injection of substance p. content of lysozyme, a specific marker of tracheal submucosal gland serous cell secretion in fe ... | 1991 | 1721905 |
| british ferrets to hungry. | | 1991 | 17749900 |
| a golgi study of dendritic development in the dorsal lateral geniculate nucleus of normal ferrets. | the development of neurons in the dorsal lateral geniculate nucleus (dlgn) of pigmented ferrets was studied by using the golgi-hortega technique. in adult ferrets, four dlgn cell classes were defined on the basis of somatic and dendritic morphology. classes 1 and 2 were divided into stellate and oriented subtypes. class 1 and 4 cells are characterized by filiform appendages, class 2 cells by club-like appendages, and class 3 cells by stalked appendages. at birth, dlgn neurons have simple dendrit ... | 1991 | 1716647 |
| the effects on the dental pulp of a composite resin and two dentine bonding agents and associated bacterial microleakage. | the pulpal reaction associated with a composite resin alone and composite resin used in conjunction with two dentine bonding agents was studied. class v cavities were prepared on the labial surfaces of the canine teeth of 18 male ferrets. after acid etching of the enamel margins, the cavities were restored with either a composite resin alone or in combination with one of two dentine bonding agents, scotchbond and gluma. one cavity in each animal was filled with kalzinol as a control. the animals ... | 1991 | 1778623 |
| testosterone in mpoa elicits behavioral but not neuroendocrine responses in ferrets. | the amount of time male ferrets were engaged in neck gripping, mounting, and thrusting was quantified in 30-min tests with a receptive female before and after castration. bilateral cannulae containing a total of approximately 2 mg testosterone propionate (tp) in cocoa butter were then stereotaxically aimed at the medial preoptic area (mpoa). tests for sexual behavior were conducted on days 3, 7, 14, and 21 postimplantation. ferrets were histologically categorized as either 1) miss (implants not ... | 1991 | 2049603 |
| vaginocervical stimulation of ferrets induces release of luteinizing hormone-releasing hormone. | abstract vaginocervical stimulation of ovariectomized estradiol-primed ferrets (which are reflex ovulators) with a glass rod in the presence of a neck-gripping male induced an increase in plasma luteinizing hormone (lh) from undetectable levels (</=0.50 ng/ml) before stimulation, to 2.4 +/- 0.43 ng/ml 75 min after stimulation (stimulated females). forty-eight h after stimulation plasma lh returned to baseline levels (post-stimulated females). a significant decrease in the number of perikarya con ... | 1991 | 19215443 |
| guanidino compound metabolism in arginine-free diet induced hyperammonemia. | guanidino compounds, intermediates of arginine metabolism, are altered in many pathological conditions especially those involving the urea cycle. arginine and creatine play an important role in nitrogen metabolism whereas other guanidino compounds such as guanidinosuccinic acid and n-acetylarginine are toxins. our objective was to investigate the relationship between guanidino compounds and hyperammonemia. young and adult ferrets were fed a single meal of either an arginine-containing diet (acd) ... | 1991 | 1815947 |
| mechanical removal of airway epithelium disrupts mast cells and releases granules. | many previous investigators have utilized mechanical rubbing as a method for examining effects of epithelial removal. in the present study, we examined whether this procedure also affects mast cell integrity in the underlying lamina propria. we isolated bronchial rings from six ferrets, and we found that removal of epithelium by rubbing decreased the total number of intact mast cells from 10.0 +/- 1.9 to 2.2 +/- 0.6 (se) mast cells/mm luminal perimeter (p less than 0.01). in addition, we found a ... | 1990 | 2260671 |
| a map of visual space induced in primary auditory cortex. | maps of sensory surfaces are a fundamental feature of sensory cortical areas of the brain. the relative roles of afferents and targets in forming neocortical maps in higher mammals can be examined in ferrets in which retinal inputs are directed into the auditory pathway. in these animals, the primary auditory cortex contains a systematic representation of the retina (and of visual space) rather than a representation of the cochlea (and of sound frequency). a representation of a two-dimensional s ... | 1990 | 2237432 |
| role of vagal afferent c fibres in the bradycardiac response to an increase in arterial blood pressure in ferrets. | the effects on baroreceptor reflexes of bilateral application of the c fibre neurotoxin, capsaicin, to the cervical vagi have been investigated in decerebrate ferrets. baroreflex sensitivity was estimated from the relationship between cardiac interval and systolic blood pressure following i.v. infusion of phenylephrine. control responses to phenylephrine were fitted by two linear slopes with an initial shallow slope, a, followed by a steeper slope, b. capsaicin abolished slope b and the resultin ... | 1990 | 2271165 |
| effects of dexmedetomidine on contractility, relaxation, and intracellular calcium transients of isolated ventricular myocardium. | the effects of the highly selective alpha 2-adrenoceptor agonist dexmedetomidine on contractility, relaxation, and the intracellular ca2+ transients of isolated ventricular myocardium were studied in isolated right ventricular papillary muscles obtained from reserpinized ferrets. dexmedetomidine (10(-10)-10(-5) m) did not alter amplitude and time variables of isometric, isotonic and zero-load-clamped twitches, except for a slight increase in maximal isotonic relaxation rate at 10(-5) m. dexmedet ... | 1990 | 1978616 |
| exposure to triphenyl phosphite results in widespread degeneration in the mammalian central nervous system. | previous studies in mammals have found that exposure to triphenyl phosphite results in cellular and axonal degeneration in the spinal cord and medulla. however, the nature of concomitant clinical signs suggested that other areas of the central nervous system might also be affected. in this study, the brains of ferrets receiving single subcutaneous injections of triphenyl phosphite were examined 8-12 days after dosing. widespread areas of axonal, terminal, and somatic degeneration were seen in me ... | 1990 | 2289128 |
| toxoplasmosis in ferrets. | | 1990 | 16031595 |
| the development of the periodontal ligament with special reference to collagen fibre ontogeny. | the development of the periodontal ligament was investigated from serial sections of the mandibles of ferrets ranging in age from 42 days to 66 days post partum. both succedaneous and non-succedaneous teeth were studied and similarities were seen in both types of tooth. no significant amounts of alveolar bone were observed being deposited beneath the erupting root apices and periodontal collagen fibres were seen attached to the walls of the sockets just prior to emergence of the crown into the o ... | 1990 | 2254296 |
| visual projections induced into the auditory pathway of ferrets. i. novel inputs to primary auditory cortex (ai) from the lp/pulvinar complex and the topography of the mgn-ai projection. | the organization of cortical circuitry responsible for processing sensory information is a subject of intense examination. however, it is not known whether cortical cells in different sensory cortices process information in a way that is specific to the modality of their input, or whether there are commonalities in processing circuitry across different cortices. in our laboratory, this question has been investigated at the level of the geniculocortical pathway by routing information of one senso ... | 1990 | 1698829 |
| emetic activity of zacopride in ferrets and its antagonism by pharmacological agents. | zacopride administered orally was more emetic in fed than in fasted ferrets. the emetic activity of zacopride (0.1 mg/kg p.o.) was inhibited (100%) by 0.1 mg/kg i.p. of zacopride and 1 mg/kg i.p. of ics 205-930. haloperidol (3.16 mg/kg i.p.) and prochlorperazine (3.16 mg/kg i.p.) were weakly effective. n-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide, a 5-ht1p antagonist, was inactive. thus, the emetic activity of zacopride, like that of cisplatin, is blocked by 5-ht3 receptor antagonists. | 1990 | 2384137 |
| retinofugal fibres change conduction velocity and diameter between the optic nerve and tract in ferrets. | in earlier studies of central nervous fibre tracts, it was tacitly assumed that individual axons are relatively uniform along their length. in the retinofugal pathway in particular, axon diameter, myelin thickness and correlated conduction properties have been treated as constant throughout the optic nerve, chiasm and tract. we report here that the conduction velocities of fibres contributing to the early components of the compound action potential are significantly greater in the optic tract th ... | 1990 | 2314474 |
| mast cell tumors in three ferrets. | pruritic open skin lesions (5 mm diameter) on the thorax, neck, or head of 3 ferrets were diagnosed as mast cell tumors. diagnosis of the tumors was based on histologic examination of biopsy specimens. histologic diagnosis was necessary because the lesions had been treated as mycotic or bacterial ulcers and did not respond to conventional treatment. excised mast cell tumors did not recur, and malignant behavior of the tumors was not observed. | 1990 | 2106501 |
| [elastase-induced hyperfunction of submucous glands develops independent of elastase-induced emphysema]. | we instilled 2 mg of pancreatic elastase into the lungs, and insufflated a further 2 mg into the trachea of 6 male ferrets. six control animals were given 0.9% nacl (lungs) and glucose powder (trachea). this combined treatment was administered on days 1, 8 and 15. on these days, and again on days 29 and 39, we obtained chest x-rays. on the 39th day, we removed the lungs and measured the mean linear intercept. in tracheal sections, we measured goblet cell density, glandular structure and function ... | 1990 | 2367425 |
| prenatal and neonatal testosterone exposure interact to affect differentiation of sexual behavior and partner preference in female ferrets. | implanting testosterone (t) subcutaneously over postnatal days 5-20 masculinized sexual behavior, reduced proceptive responsiveness, and shifted sexual preference more readily in male than in female ferrets gonadectomized on day 5. this enhanced sensitivity of males to neonatal t was best duplicated in females exposed transplacentally to t over embryonic days (e) 27-39 (41-day gestation) and injected at birth with t (2.5 micrograms sc in oil: 10% ethanol). extended exposure of male ferrets to hi ... | 1990 | 2317276 |
| prechiasmatic reordering of fibre diameter classes in the retinofugal pathway of ferrets. | this study examines the distribution of fibre diameter classes at various sites along the retinofugal pathway of adult ferrets. light microscopic observations were made on semi-thin sections, and regional fibre diameter spectra were constructed from diameter measurements taken from electron micrographs of thin sections of the intraorbital optic nerve (2.5 mm from the optic disc), the intracranial optic nerve (1 mm rostral to the fusion of the nerves), and the optic tract (just caudal to the opti ... | 1990 | 12106100 |
| antitumor activity and toxicity in animals of n-7[2-(4-nitrophenyldithio) ethyl] mitomycin c (bmy-25067). | bmy-25067, n-7[2-(4-nitrophenyldithio)-ethyl] mitomycin c was selected from a number of disulfide derivatives of the highly active compound rr150, n-7(thioethyl) mitomycin c for further study. bmy-25067 had tumor inhibitory effects equivalent to mitomycin c (mmc) against ascitic p388 and l1210 leukemias and m109 lung carcinoma in mice with i.p. treatment. however, it demonstrated superior activity against b16 melanoma with a high percentage of cures when both tumors and drug were given i.p. addi ... | 1990 | 2380013 |
| changes in airway length after unilateral pneumonectomy in weanling ferrets. | we have previously shown that airway cross-sectional area increases 15-20% after pneumonectomy in weanling ferrets by measuring bronchial casts. we have now reanalyzed these same casts to quantitate changes in airway length after pneumonectomy. in each cast the distance from each of 120 airways to the terminal bronchiole along its axial pathway was measured. the relationship between the logarithm of this distance and that of the fraction of the lobe subtended by an airway could be described by a ... | 1990 | 2312458 |
| real-time ultrasonographic determination of pregnancy and gestational age in ferrets. | | 1990 | 2153873 |
| photoperiodic regulation of gonadal growth and pulsatile luteinizing hormone secretion in male ferrets. | testicular growth was monitored in male ferrets subjected to one of the following photoperiodic treatments begun at weaning (8 weeks of age): 8 hr light/day (short days), 18 hr light/day (long days), or short days followed by transition to long days at either 10, 12, or 14 weeks of age. mean ages to achieve adult testis width of greater than or equal to 12 mm were 27.5 +/- 1.3, 25.0 +/- 1.5, 23.6 +/- 2.9, 20.0 +/- 0.8, and 21.2 +/- 1.0 weeks in ferrets raised from weaning in long days, raised fr ... | 1990 | 2133130 |
| dynamics of intercellular communication and differentiation in a rapidly developing mammalian airway epithelium. | a considerable body of data suggests that gap junctions represent channels that facilitate intercellular communication, thereby modulating growth and development. however, direct quantitative evidence supporting such a structure/function relationship is limited. this study has identified a new model in the rapidly developing tracheal epithelium of infant ferrets wherein gap junction prevalence and intercellular transfer of a fluorescent, low molecular weight dye, epithelial cell incorporation of ... | 1989 | 2637755 |
| proliferative colitis in ferrets: epithelial dysplasia and translocation. | | 1989 | 2603333 |
| prolactin or dopamine mediates the induction of puberty by long days in female ferrets. | the role of prl in sexual maturation of female ferrets was examined in these studies. longitudinal profiles of prl secretion were obtained by thrice weekly blood sampling of intact female ferrets undergoing photoperiod-stimulated development as well as age-matched control females which remained in nonstimulatory short days. two additional groups of intact females, one in each photocycle, were treated with the dopamine agonist drug bromocriptine throughout the study. the relationship between deve ... | 1989 | 2507293 |
| ferrets and the profession. | | 1989 | 2815525 |
| proven or potential zoonotic diseases of ferrets. | | 1989 | 2676931 |
| early monocular enucleations in fetal ferrets produce a decrease of uncrossed and an increase of crossed retinofugal components: a possible model for the albino abnormality. | the terminal distributions of retinofugal axons to geniculate laminae or cell groups have been studied in monocular ferrets that had had one eye removed on the 28th or 29th day of intrauterine life and survived until the end of the fourth postnatal week. normally pigmented and albino animals were studied and the patterns of retinogeniculate terminations in these were compared with earlier accounts of the patterns that develop normally or after a monocular enucleation on the day of birth. birth n ... | 1989 | 2606796 |
| evaluation of a combination of tiletamine and zolazepam as an anesthetic for ferrets. | a combination of equal parts by weight of tiletamine hyrochloride and zolazepam hydrochloride was evaluated clinically in 12 adult male ferrets. two dosage levels of 12 mg/kg and 22 mg/kg were evaluated. both doses produced excellent immobilization, the length of which was dose dependent. however, only the higher dose consistently produced good muscle relaxation. excessive pain upon infection was not noted nor was residual lameness evident. electrocardiagraphically, notching of the qrs complex w ... | 1989 | 2724926 |
| semen characteristics and testosterone profiles in ferrets kept in a long-day photoperiod, and the influence of hcg timing and sperm dilution medium on pregnancy rate after laparoscopic insemination. | five domestic ferrets previously maintained for 12 weeks under a 16l:8d photoperiod were electroejaculated weekly for 15-65 weeks while continuing to be exposed to the prolonged light cycle. two ferrets sustained spermatogenesis for 20 and 26 weeks, while sperm production in the remaining males either was sporadic or decreased, remained depressed and then increased to peak levels observed in other males. regardless of the temporal spermatogenesis patterns within males, the number of electroejacu ... | 1989 | 2526874 |
| pet ferrets--a hazard to public health and wildlife. | | 1989 | 2735056 |
| attack ferrets? | | 1989 | 2918650 |
| effects of soman and its antidotes on tracheal mucociliary transport of ferrets. | the purpose of this study was to examine the role of acetylcholinesterase on mucociliary transport by use of a potent anticholinesterase agent, soman, and potential antagonists, atropine (muscarinic antagonist) and pralidoxime (acetylcholinesterase reactivator). initial measurements of mucociliary transport rate were obtained in anesthetized ferrets at 30-min intervals for 5.5 h. these rates remained constant at a mean of 18.2 +/- 1.0 (se) mm/min. we studied the effects of intravenously administ ... | 1989 | 2496095 |
| scent lures from anal sac secretions of the ferretmustela furo l. | a bioassay of eight synthetic anal sac compounds showed that ferrets were most attracted to a mixture of 2-propylthietane andtrans- andcis-2,3-dimethylthietane. this mixture was used as the basis of an artificial scent lure. trapping experiments used two traps at each site. in comparing trap success, ferrets chose artificial lure in preference to no odor, and chose both food baits and natural-product anal sac odor over artificial lure. however, the effectiveness of artificial lure was demonstrat ... | 1989 | 24271444 |
| guardians, ferrets and defilers of the treasure: the masson-freudians controversy. | | 1989 | 11621786 |
| pharmacological and anti-emetic properties of ondansetron. | three main types of 5-ht (serotonin) receptor have been recognised. the 5-ht3 receptor is located on neuronal tissues in the peripheral and central nervous systems. ondansetron is a highly selective and potent antagonist for this receptor type. the severe nausea and vomiting caused by cytotoxic agents and radiotherapy can be reduced by metoclopramide treatment, but extrapyramidal side effects are common due to antagonism of dopamine receptors. ondansetron has been found to significantly delay th ... | 1989 | 2533894 |
| experimentally induced visual projections into auditory thalamus and cortex. | retinal cells have been induced to project into the medial geniculate nucleus, the principal auditory thalamic nucleus, in newborn ferrets by reduction of targets of retinal axons in one hemisphere and creation of alternative terminal space for these fibers in the auditory thalamus. many cells in the medial geniculate nucleus are then visually driven, have large receptive fields, and receive input from retinal ganglion cells with small somata and slow conduction velocities. visual cells with lon ... | 1988 | 2462279 |
| more on ferrets as pets. | | 1988 | 3192469 |
| a tethered-restraint system for blood collection from ferrets. | | 1988 | 3193763 |
| ferrets as pets. | | 1988 | 3403344 |
| differential effects of testosterone, 5 alpha-dihydrotestosterone and oestradiol-17 beta on plasma concentrations of lh in castrated ferrets. | the biological activity of testosterone often depends on the conversion of testosterone within the target cell to an androgenic or oestrogenic metabolite. the purpose of this study was to compare the relative ability of testosterone and two of its metabolites, dihydrotestosterone (dht) and oestradiol, to suppress lh secretion in castrated male ferrets. castrated ferrets were treated with five different doses of steroid by implanting various numbers of s.c. silicone elastomer capsules packed with ... | 1988 | 3392501 |
| minimum alveolar concentrations (mac) of halothane, enflurane, and isoflurane in ferrets. | the minimum alveolar concentrations (mac) of isoflurane, enflurane, and halothane were determined in adult male ferrets during controlled ventilation at normothermia (37 degrees c). mean (+/- sd) mac values for isoflurane (n = 8), enflurane (n = 8), and halothane (n = 8) at 37 degrees c were 1.52 +/- 0.10%, 1.99 +/- 0.18%, and 1.01 +/- 0.10%, respectively. halothane mac was reduced by 26% in the presence of 70% n2o. at 29.9 +/- 0.2 degrees c, the mean mac value of halothane (0.85 +/- 0.11%) was ... | 1988 | 3369718 |
| severe facial injuries to infants due to unprovoked attacks by pet ferrets. | three infants were attacked by pet ferrets and sustained severe facial injuries. two of the children had their ears bitten off and required reconstructive surgery. the attacks were unprovoked. two of the children were asleep in their cribs when they were bitten. although ferrets are increasingly popular pets, we believe that they are not suitable pets for families with small children. physicians should be aware that ferrets may unpredictably injure infants and that no effective rabies vaccine fo ... | 1988 | 3346981 |
| a study of cerebellar cortical involvement in motor learning using a new avoidance conditioning paradigm involving limb movement. | these experiments were performed to examine the relationship between the simple and complex spike responses of 3-5 simultaneously recorded purkinje cells during the acquisition, performance and extinction of a conditioned forelimb movement in decerebrate, unanesthetized ferrets. the data demonstrate parallel, correlated changes in simple and complex spike responses throughout the experimental period. since the evaluated purkinje cells were examined in the cerebellar cortical region that contains ... | 1988 | 3365554 |
| developmental plasticity in the visual and auditory representations in the mammalian superior colliculus. | environmental factors play an important role in certain aspects of the development of sensory systems. but the way in which the maturation of different sensory modalities is coordinated is poorly understood. we have investigated this question neurophysiologically in the mammalian superior colliculus (sc), which contains topographically aligned maps of visual and auditory space. we report here that an essentially normal auditory map, in approximate register with the visual map, is found in the sc ... | 1988 | 3347247 |
| a simple technique for chronic jugular catheterization in ferrets. | | 1988 | 3367631 |
| effect of birth on plasma testosterone, brain aromatase activity, and hypothalamic estradiol in male and female ferrets. | the present studies examined the patterns of circulating testosterone (t) within 0-24 h after birth in male and female ferrets along with concomitant changes in neural aromatase activity and hypothalamic concentrations of estradiol (e2). plasma and brain samples were obtained 0 and 2 h (cesarean delivery) or 0, 2, 12, and 24 h (natural delivery) after birth. plasma t levels were significantly higher in male neonates 2 h after birth than at 0 h in both cesarean-delivered (9.48 +/- 1.25 vs. 3.37 + ... | 1988 | 3338412 |
| immunocytochemical localization of hypothalamic luteinizing hormone-releasing hormone in male ferrets. | lhrh-containing neurons within the hypothalamus were immunocytochemically identified in adult male ferrets that were either gonadally intact, castrated, or castrated and treated with testosterone. the distribution of lhrh-immunopositive neuron cell bodies was similar in the three treatment groups. the majority of these cells was located mediobasally in the retrochiasmatic area, including some within the ventrolateral aspects of the arcuate nucleus. these soma were associated with a dense basal l ... | 1988 | 3285966 |
| a new conditioning paradigm: conditioned limb movements in locomoting decerebrate ferrets. | these experiments address the hypothesis that the trajectory of a forelimb in decerebrate ambulating ferrets can be conditioned to avoid an obstacle encountered during the locomotor cycle. the perturbation was produced by interjecting a bar into the trajectory of the forelimb during swing phase. over 5-15 steps the flexion of the elbow progressively increased until the forelimb was elevated over the bar. avoiding the bar often required that the maximum height of the paw during swing phase was do ... | 1988 | 3340324 |
| interaction of contact velocity and cord compression in determining the severity of spinal cord injury. | rate, depth, and duration of compression are the principal determinants of experimental spinal cord injury (sci) severity. since existing models do not allow independent control of these variables, the interaction of these factors has not been fully elucidated. the purpose of this study was to define the interactive relation of velocity (v) and compression (c) in sci using a constrained stroke pneumatic impactor that allowed independent control of these variables. computer simulation of previous ... | 1988 | 3246693 |
| effect of systemic nicotine on mucus secretion from tracheal submucosal glands and on cardiovascular, pulmonary, and hematologic variables. | to investigate effects of systemic nicotine on mucus secretion from tracheal submucosal glands we anesthetized 13 ferrets (5 male, 8 female; average weight 1138 +/- 469 g, mean +/- sd) with pentobarbital (initial dose, 62 +/- 26, total dose, 90 +/- 26 mg/kg), cannulated the jugular vein for i.v. application of infusions and drugs and cannulated the femoral artery for determination of blood pressure, heart rate, blood cells, and blood gases. we opened the thorax, cannulated the trachea 1 cm above ... | 1988 | 3184774 |
| stimulation of submucosal glands by nicotine applied locally to the airway mucosa. | chronic bronchitis is characterized by hypersecretion of mucus and is caused by cigarette smoking. we investigated the effect of nicotine on mucus secretion from tracheal submucosal glands, applying nicotine to the airway mucosa in vitro. we anesthetized 50 ferrets with pentobarbital (66 mg/kg), excised their tracheae and mounted tracheal segments in ussing chambers. we added 50 microci na(2)35so4 (35s) to the submucosal side and determined nondialyzable 35s in medium collected from the luminal ... | 1988 | 3184773 |
| effects of partial truncal vagotomy on intragastric pressure responses to vagal stimulation and gastric distension in ferrets. | changes in intragastric pressure after dorsal truncal vagotomy, investigated by stimulation of the surviving vagal branches and by step inflation of the stomach, were divided into an early phase lasting five days, and a late phase continuing for at least three months. during the early phase the amplitude of vagal evoked contraction was diminished but the resting pressure and the response to gastric inflation were increased. after the fifth day vagal evoked contractions doubled in amplitude but t ... | 1987 | 3428683 |
| early uncrossed component of the developing optic nerve with a short extracerebral course: a light and electron microscopic study of fetal ferrets. | during the study of the developing optic nerve described in the preceding paper (guillery and walsh, '87), small bundles of nerve fibers were seen passing between the optic nerve and the ipsilateral hypothalamus of 24-to 27-day-old prenatal ferrets. the bundles appear before any other fiber groups of the retinofugal pathway and are identifiable while the main portions of the retinofugal system are growing into the optic tracts. the bundles, made up of 50 or more axons, leave the optic nerve, eme ... | 1987 | 3693607 |
| changing glial organization relates to changing fiber order in the developing optic nerve of ferrets. | the structures of the developing eye-stalk and the relationships of early retinofugal fibers as they pass through the stalk, chiasm, and tract have been studied by light and electron microscopical methods in fetal ferrets aged 23-27 days. the early eye-stalk can be divided into two parts: a narrow extracranial part has a narrow lumen and is lined by few cells, whereas a thicker intracranial part has a wider lumen and is lined by several rows of cells. at the earliest stages no axon bundles are r ... | 1987 | 3693606 |
| inhalation toxicity of ribavirin in suckling ferrets. | ribavirin is a broad-spectrum antiviral agent useful for treatment of infants. to study the effects in developing mammalian lungs, four groups of jill ferrets and their litters were given whole body inhalation exposures for 6 h a day for 10 or 30 consecutive days to concentrations of 0 (vehicle control), 162, 355 or 620 mg/m3. the effects, including special lung observations in suckling kits, were evaluated after exposures at weaning and at puberty. first the high dose, then the mid dose jills d ... | 1987 | 3680851 |
| evidence that a decrease in testosterone negative feedback mediates the pubertal increase in luteinizing hormone pulse frequency in male ferrets. | neuroendocrine mechanisms regulating luteinizing hormone (lh) secretion during puberty were investigated in intact male ferrets and ferrets castrated at 8 wk of age that received s.c. implants of either empty or testosterone-filled silastic capsules. to synchronize puberty onset among individuals, ferrets were exposed to short days between 8 and 16 wk of age, and then transferred to long days. testis growth began in intact ferrets soon after photoperiod transition. blood samples were obtained at ... | 1987 | 3651552 |
| evidence that 5-hydroxytryptamine3 receptors mediate cytotoxic drug and radiation-evoked emesis. | the involvement of 5-hydroxytryptamine (5-ht) 5-ht3 receptors in the mechanisms of severe emesis evoked by cytotoxic drugs or by total body irradiation have been studied in ferrets. anti-emetic compounds tested were domperidone (a dopamine antagonist), metoclopramide (a gastric motility stimulant and dopamine antagonist at conventional doses, a 5-ht3 receptor antagonist at higher doses) and brl 24924 (a potent gastric motility stimulant and a 5-ht3 receptor antagonist). domperidone or metoclopra ... | 1987 | 3311109 |
| habitat structure and predators: choices and consequences for rodent habitat specialists and generalists. | both habitat structure and risk of predation are thought to influence rodent community composition in different habitats, but experiments on the degree to which these factors determine the use of habitat by rodents are lacking. i sought to discover (1) if cover density altered habitat choice and (2) if cover density affected the vulnerability to predators of two rodents, a habitat specialist and a habitat generalist. in laboratory experiments, the habitat specialist, the red-backed vole (clethri ... | 1987 | 28312894 |
| toxicity of thiram (tetramethylthiuram disulfide) to mink and european ferrets. | | 1987 | 3567399 |
| [halothane intubation anesthesia during controlled respiration in ferrets]. | | 1987 | 3673292 |
| effects of the paf-antagonist cv-3988 on paf-induced changes in mucus secretion and in respiratory and circulatory variables in ferrets. | | 1987 | 3479001 |
| [aplastic anemia in ferrets]. | the present report describes both estrus associated and estrogen induced aplastic anemia in 7 female ferrets. the animals were presented with anemia, anorexia, apathy, melena and subcutaneous hemorrhages. histologically, the animals showed panmyelophthisis and cystic endometrial hyperplasia. | 1987 | 3424362 |
| effects of cyproterone acetate on mating behavior, testicular morphology, testosterone level, and body temperature in male ferrets in comparison with normal and castrated males. | effects of surgical castration of 60-day-old male ferrets are compared with the effects of a chemical castration with cyproterone acetate from postnatal day 60 until 360. investigations were made on mating behavior, intermale aggression, testicular morphology, plasma testosterone level and body temperature. while controls show seasonal variations in all parameters, according to the annual cycle of sexual activity and inactivity, both, surgically and chemically castrated ferrets show throughout t ... | 1987 | 2952572 |
| inhibition of cisplatin-induced vomiting by selective 5-hydroxytryptamine m-receptor antagonism. | mdl 72222, the selective 5-hydroxytryptamine (5-ht) m-receptor antagonist, prevented or reduced cisplatin-induced emesis in ferrets. it is suggested that cisplatin-induced, and possibly other cytotoxic drug-induced vomiting may involve a 5-ht m-receptor mechanism. | 1986 | 3742146 |
| ferrets as pets. | | 1986 | 3721957 |
| effect of arginine-free diet on ammonia metabolism in young and adult ferrets. | two-month-old, male ferrets were fasted for 16 h and fed a synthetic, arginine-free diet. within 2-3 h after ingesting the diet, they developed hyperammonemia and encephalopathy. ammonia levels in the serum, brain and cerebrospinal fluid were greatly elevated compared to those of ferrets fed the synthetic diet supplemented with arginine. orotic acid and glucose levels in serum were also significantly elevated. urinary orotic acid was significantly increased but citrate and creatinine level were ... | 1986 | 3958802 |
| [heat perils in ferrets]. | | 1986 | 3952723 |
| plasma and pineal melatonin levels in female ferrets housed under long or short photoperiods. | ovohysterectomized female ferrets were housed in controlled environment rooms in which the daily lighting schedule was either 15l:9d (long days) or 9l:15d (short days). after 2 weeks some ferrets in each group were given an intrajugular catheter: beginning 1 week later, a blood sample was taken daily at one of eight different clock times over an 8 to 10 day period. one additional blood sample plus the pineal gland were collected from these animals and from uncathetarized animals in each group af ... | 1986 | 3955143 |
| effect of prenatal exposure to aromatase inhibitor, testosterone, or antiandrogen on the development of feminine sexual behavior in ferrets of both sexes. | experiments were conducted to assess the role of prenatal exposure of the brain to estrogen in controlling the development of proceptive and receptive feminine sexual behavior in ferrets of both sexes. female ferrets, deprived prenatally of estrogen via maternal ovariectomy on gestational day 30 (42-day gestation) plus sc implantation of an aromatase inhibitor, 1,4,6-androstatriene-3,17-dione (atd), into their mothers, were significantly less receptive than control females when tested in adultho ... | 1986 | 3737708 |
| effects of platelet activating factor on tracheal mucus secretion, on airway mechanics and on circulating blood cells in live ferrets. | | 1986 | 3465554 |
| olfactory deprivation enhances normal spine loss in the olfactory bulb of developing ferrets. | ferrets show a sensitive phase in their postnatal development during which they can become imprinted to food odors. at the same time the number of granule cell spines in the olfactory bulb reaches a maximum, declining significantly thereafter. in ferrets, exposed continuously to saturated levels of geraniol odor in the cage environment, the normal decline in spine number (occurring between day 60 and 90) is significantly enhanced. no such effects were observed during earlier ontogenetic phases. ... | 1985 | 4088530 |
| influence of day length and endocrine status on luteinizing hormone secretion in intact and ovariectomized adult ferrets. | the purpose of this study was to examine the pituitary-ovarian relationship of both estrous and anestrous female ferrets. the endocrine status of the animals was induced by manipulating photoperiod: females in estrus were housed in long days (16l:8d); females in anestrus were housed in short days (8l:16d). for studies of intact animals in both photoperiods, plasma luteinizing hormone (lh) levels were quantified in blood samples collected from adult ferrets at 5-min intervals over a 24-h period. ... | 1985 | 4052529 |
| migration and differentiation of cerebral cortical neurons after transplantation into the brains of ferrets. | cells from the cerebral proliferative zones of newborn ferrets were labeled with tritiated thymidine and a fluorescent dye and were transplanted as a single-cell suspension into the occipital region of newborn ferrets. the transplanted cells became thoroughly integrated into the host environment: many cells migrated through the intermediate zone and into the cortical plate, where they developed as pyramidal neurons. other transplanted cells came to resemble glial cells. after 1 to 2 months most ... | 1985 | 4035355 |
| comparisons of tracheostomy incisions in a pediatric model. | tracheostomy in children causes approximately twice the mortality and morbidity as in the adult. the occurrence of complications correlates closely with the severity of the preoperative tracheal disease, the length of time the tracheostomy is needed, and the age of the patient. morbidity documented in the postoperative period includes tracheal stenosis and collapsible anterior tracheal wall. the increased incidence of these problems in the pediatric patient may be related to the less rigid natur ... | 2017 | 4051401 |
| evidence of proceptive without receptive defeminization in male ferrets. | the latencies of groups of gonadectomized male and female ferrets to approach and interact with a sexually active stimulus male were measured after administration of estradiol benzoate (eb; 0, 5, 10, or 15 micrograms/kg) in adulthood. receptive responsiveness to stud males was also assessed in these same ferrets during additional tests. control female ferrets gonadectomized on postnatal day 35 displayed a dose-dependent reduction in approach latencies to the stud male which did not occur in cont ... | 1985 | 3843738 |
| maturation of ovarian function in female ferrets is influenced by photoperiod. | sexual maturation of immature ferrets in response to a stimulatory photoperiod generally occurs within 6-7 weeks after imposition of long days at 16 weeks of age. in this study, females were examined for evidence of ovarian maturation after 22 days of exposure to the stimulatory photoperiod, before any sign of sexual maturation. the photoperiod-stimulated and control females were the same age (19 weeks), had similar body weights, and showed no evidence of vulvar oedema. comparison of oestradiol ... | 1985 | 4045818 |
| bone marrow hypoplasia associated with estrus in ferrets. | bone marrow hypoplasia was characterized in a group of female ferrets during prolonged estrus. all ferrets exhibited hematological changes characteristic of various degrees of bone marrow hypoplasia. hematological findings included initial thrombocytosis and leukocytosis followed by thrombocytopenia, leukopenia and anemia. platelet counts below 50,000/microliters were observed in 55% of the ferrets. hemorrhagic anemia due to thrombocytopenia was the most common cause of death and the mortality r ... | 1985 | 4040589 |
| restraint device for serial blood sampling of ferrets. | a device was designed that effectively restrained unanesthetized ferrets for serial blood sampling from the caudal artery. materials used for construction were inexpensive and easily obtained. fabrication was simple and rapid. | 1985 | 4021441 |
| ferrets in biomedical research. | | 1985 | 4021434 |
| a technique for quantitating airway size from bronchial casts. | to develop a technique for quantitating the size of airways at various positions in the bronchial tree, we analyzed casts of formalin-fixed excised lungs of five mature male ferrets. the left lower lobe of each cast was dissected, the diameter and position of each terminal bronchiole were entered into a computer programmed to reconstruct the airway system, and the cross-sectional areas of 120 conducting airways were measured. the fraction of the lobe served by each measured airway was estimated ... | 1985 | 3980372 |
| retinotopic order appears before ocular separation in developing visual pathways. | in mammals, the major subcortical visual structures receive projections from both eyes, with the uncrossed projection being smaller than the crossed. each projection is arranged as a separate orderly map of one hemiretina. although these hemiretinal maps are separate in the nuclei, they are aligned so that the representations of points in the visual field are in register, thus there is a continuity of visual field representation between them. during the early development of the binocular pathway ... | 2007 | 3969159 |
| l-dopa and apomorphine disrupt long- but not short-behavioural chains. | apomorphine (0.01-0.5 mg/kg) disrupted fighting between two male ferrets. the number of bites and neck nuzzling were decreased dose-dependently. at 0.05 and 0.1 mg/kg scent-marking and collateral behaviour were increased, at 0.5 mg/kg stereotyped sniffing was induced. l-dopa (120 mg/kg + 30 mg/kg benserazide) exerted similar effects to apomorphine 0.05 mg/kg. thus, the dopamine (da) agonists increased short chain responses but disrupted long ones. haloperidol (0.2 mg/kg) facilitated inter-male f ... | 1984 | 6522487 |
| adenosine and hypoxic pulmonary vasodilation. | we have previously shown that after exposure to an inspired o2 tension less than 25 torr, isolated lungs perfused with autologous blood exhibit vasoconstriction followed by dilation. because adenosine has been implicated as a mediator of hypoxic vasodilation in the systemic circulation and because the concentration of adenosine in the lung has been shown to increase with hypoxia, we tested the hypothesis that adenosine is the mediator of hypoxic pulmonary vasodilation. we first confirmed that ad ... | 1984 | 6437241 |
| neural regulation of 35so4-macromolecule secretion from tracheal glands of ferrets. | our goal was to determine what nervous mechanisms mediate the secretion of macromolecules from tracheal submucosal glands of ferrets. to do this, we studied the secretion of 35so4-labeled macromolecules in vitro in response to electrical or pharmacological stimulation in the absence and presence of a specific nerve blocker and autonomic antagonists. we found that electrical field stimulation and the agonists acetylcholine, phenylephrine, terbutaline, and norepinephrine each cause secretion of ra ... | 1984 | 6469816 |
| effects of chronic dietary hexachlorobenzene exposure on the reproductive performance and survivability of mink and european ferrets. | | 1984 | 6742893 |
| a procedure for descenting ferrets. | | 1984 | 6738516 |
| a chemical procedure for loading the calcium indicator acquorin into mammalian working myocardium. | the bioluminescent calcium indicator aequorin was successfully loaded into mammalian working myocardium of ferrets by a chemical procedure which makes the cells reversibly hyperpermeable through exposure to ethylenebis-( oxyethylenenitrilo ) tetraacetic acid (egta). after undergoing the loading procedure, developed tension at lmax was 103 +/- 26% of the control, which indicates that the muscles regained normal function. the configurations of the aequorin signals (i.e., calcium transients) and th ... | 1984 | 6728654 |
| plasma concentrations of oestradiol and oestrone during perinatal development in male and female ferrets. | the concentrations of oestradiol and oestrone in peripheral plasma of male and female ferrets 5 days before and 7, 15 and 30 days after birth were measured. both steroids were present in high concentrations prenatally. much lower levels were found in samples collected on day 7 and later, when the concentrations were similar to those of adult gonadectomized animals. no significant sex difference was seen for the concentration of either steroid at any age studied. these results, and those previous ... | 1984 | 6693827 |