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PubMedDate not supplied

Behavioral effects of prenatal exposure to ethylene dibromide.

Pregnant female Long-Evans hooded rats were exposed to 0, 0.43, 6.67, or 66.67 ppm ethylene dibromide (EDB) via inhalation for four hours/day three days/week from Day 3 to Day 20 of gestation. The 66.67 ppm dose produced an increase in defecation during exposure, decreased gestational weight gain, and enhanced rotorod performance and T-maze brightness discrimination acquisition in the offspring. Similar changes were noted in the dams and offspring exposed to 6.67 ppm, but the magnitude of the effects was reduced. No effects of exposure to 0.43 ppm were detected, nor were litter size, litter composition, nest building, pup retrieval, DRL-20 acquisition, straight alley running speed, or passive avoidance affected by exposure to any dose. We suggest that the behavioral effects of the medium and high doses may be secondary to stress reactions in the dams to exposure to these doses.

Animals↗
PubMed1994

Dysembryoplastic neuroepithelial tumor. A tumor with small neuronal cells resembling oligodendroglioma.

Dysembryoplastic neuroepithelial tumor (DNT) is a clinicopathologically unique group of tumors, mostly located in the temporal lobe, associated with intractable complex partial seizure in young patients. We report two unusual cases with multifocal involvement of diverse sites in the central nervous system. Case 1 is that of a 50-year-old man with 9-year history of grand mal seizures, who died of acute myocardial infarction. Case 2 is that of a 10-year-old girl with intractable complex partial seizures and behavioral disorder. Postmortem examination in case 1 showed multifocal tumor in the left temporal lobe, third ventricle, and basal ganglia. Magnetic resonance imaging in case 2 showed tumor in the right temporal lobe, both thalami, right cerebellar hemisphere, and pons. Histologically, both tumors were characterized by a multinodular appearance with a predominant component of alveolar arrangement of oligodendroglial-like cells around delicate capillaries, with mucoid matrix containing floating ganglion cells. There were also astrocytic nodules resembling pilocytic astrocytoma in case 1, and a gangliocytoma-like area merging with surrounding cortical dysplasia in case 2. Ultrastructural examination showed ganglionic differentiation in the oligodendroglial-like cells in case 2. They possessed dense core neurosecretory granules and many slender neuritic processes with microtubules arranged in parallel and terminating in synaptic junctions. The periventricularly located tumor with nodular extension to the periphery suggests an origin from subependymal germinal matrix with nests of primitive neuroblasts arrested in their embryonal migration. DNTs are related to ganglioglioma based on their common location and clinical behavior and on the presence of both ganglionic and astrocytic cells. They are also related to pilocytic astrocytoma by morphological and behavioral similarity. Together with cerebral neuroblastoma and central neurocytoma, they form a spectrum of tumors harboring small neuronal cells. The differentiation of DNT from oligodendroglioma is important so as to avoid unnecessarily aggressive therapy.

Brain Neoplasms↗
PubMed2005

Methamphetamine administration during gestation impairs maternal behavior.

Previous studies demonstrated that repeated drug exposure, such as opiates or cocaine, during the gestation period attenuates maternal behavior of rats; however, it is not known whether methamphetamine (MA), a drug whose usage has increased recently, negatively affects maternal behavior as well. Therefore, the present study tested the hypothesis that repeated subcutaneous administration of MA (5 mg/kg daily) throughout the entire gestation period alters maternal behavior. Dams (control, saline-, and MA-treated) were observed with their pups in two types of tests. In the observation test, 11 types of activities and three types of nursing positions of mothers were recorded 10 times during each 50-min session for the 22-day lactation period. A decrease in nursing and active maternal behavior was found in MA-treated mothers relative to control rats. In addition, stereotypic behavior such as rearing and sniffing was increased in MA- as well as in saline-treated mothers relative to controls. All mothers, regardless of the treatment, displayed significantly less maternal behavior and more nonmaternal activities as postpartum time progressed. In the retrieval test, mothers also were tested for pup retrieval from postpartum Days 1 through 12. MA-treated mothers were slower in retrieving the first pup, returning the first pup into the nest, and returning all pups into the nest relative to controls or saline-treated mothers. Interestingly, the latency to return all pups to the nest was longer in saline-treated mothers relative to controls. In conclusion, the present study demonstrates a novel finding that MA administered during the gestation period has a negative effect on maternal behavior.

Adrenergic Agents↗
PubMed1997

Allosteric properties of inosine monophosphate dehydrogenase revealed through the thermodynamics of binding of inosine 5'-monophosphate and mycophenolic acid. Temperature dependent heat capacity of binding as a signature of ligand-coupled conformational equilibria.

The thermodynamic properties of binding of the substrate, inosine monophosphate (IMP), and the uncompetitive inhibitor, mycophenolic acid, to inosine monophosphate dehydrogenase (IMPDH) were measured. Specifically, the free energy, enthalpy, entropy, and heat capacity changes were determined for each ligation state of the tetrameric enzyme, over a temperature range from 2.5 to 37 degrees C by high-precision titration microcalorimetry. It was discovered that IMP binds to IMPDH in a negatively cooperative fashion and that mycophenolic acid binding is critically dependent on the presence of IMP. Moreover, the binding of IMP is entropically driven at low temperatures and enthalpically driven at high temperatures, with an unusually large, temperature dependent heat capacity change. A thermodynamic argument, based on the general nature of the heat capacity function for a binding reaction and its temperature dependence, is used to infer the existence of an equilibrium mixture of at least two structural forms of apo-IMPDH. The equilibrium is perturbed in the presence of IMP and mycophenolic acid, suggesting a mechanism for the ligand-linked conformational changes. An allosteric model, incorporating subunit-subunit interactions nested within a concerted conformational change involving the entire tetrameric macromolecule, is proposed to account for the observed binding behavior. The implications of these findings for the design of novel "allosteric-effector" inhibitors of IMPDH, to be used for the purpose of immunosuppression, are discussed.

Allosteric Regulation↗
PubMed1999

Role of multistability in the transition to chaotic phase synchronization.

In this paper we describe the transition to phase synchronization for systems of coupled nonlinear oscillators that individually follow the Feigenbaum route to chaos. A nested structure of phase synchronized regions of different attractor families is observed. With this structure, the transition to nonsynchronous behavior is determined by the loss of stability for the most stable synchronous mode. It is shown that the appearance of hyperchaos and the transition from lag synchronization to phase synchronization are related to the merging of chaotic attractors from different families. Numerical examples using Rossler systems and model maps are given. (c) 1999 American Institute of Physics.

Journal Article↗
PubMed2001

A single ancient origin of brood parasitism in African finches: implications for host-parasite coevolution.

Robust phylogenies for brood-parasitic birds, their hosts, and nearest nesting relatives provide the framework to address historical questions about host-parasite coevolution and the origins of parasitic behavior. We tested phylogenetic hypotheses for the two genera of African brood-parasitic finches, Anomalospiza and Vidua, using mitochondrial DNA sequence data from 43 passeriform species. Our analyses strongly support a sister relationship between Vidua and Anomalospiza, leading to the conclusion that obligate brood parasitism evolved only once in African finches rather than twice, as has been the conventional view. In addition, the parasitic finches (Viduidae) are not recently derived from either weavers (Ploceidae) or grassfinches (Estrildidae), but represent a third distinct lineage. Among these three groups, the parasitic finches and estrildids, which includes the hosts of all 19 Vidua species, are sister taxa in all analyses of our full dataset. Many characters shared by Vidua and estrildids, including elaborate mouth markings in nestlings, unusual begging behavior, and immaculate white eggs, can therefore be attributed to common ancestry rather than convergent evolution. The host-specificity of mouth mimicry in Vidua species, however, is clearly the product of subsequent host-parasite coevolution. The lineage leading to Anomalospiza switched to parasitizing more distantly related Old World warblers (Sylviidae) and subsequently lost these characteristics. Substantial sequence divergence between Vidua and Anomalospiza indicates that the origin of parasitic behavior in this clade is ancient (approximately 20 million years ago), a striking contrast to the recent radiation of extant Vidua. We suggest that the parasitic finch lineage has experienced repeated cycles of host colonization, speciation, and extinction through their long history as brood parasites and that extant Vidua species represent only the latest iterations of this process. This dynamic process may account for a significantly faster rate of DNA sequence evolution in parasitic finches as compared to estrildids and other passerines. Our study reduces by one the tally of avian lineages in which obligate brood parasitism has evolved and suggests an origin of parasitism that involved relatively closely related species likely to accept and provide appropriate care to parasitic young. Given the ancient origin of parasitism in African finches, ancestral estrildids must have been parasitized well before the diversification of extant Vidua, suggesting a long history of coevolution between these lineages preceding more recent interactions between specific hosts and parasites.

Animals↗
PubMed2006

The many faces and mimics of papillary thyroid carcinoma.

This article provides an overview of the 15 histologic variants of papillary thyroid carcinoma listed by the 2004 World Health Organization (WHO) monograph on endocrine tumors. The histologic features, differential diagnosis, and clinical course of each variant are discussed in some detail. The follicular variants (conventional and macrofollicular) constitute a morphologic challenge because the majority of these tumors are encapsulated and, also, because, in many tumors, not all neoplastic cells show the nuclear features considered to be diagnostic of papillary carcinoma. As a result, most of these tumors are missed even by experienced pathologists. Moreover, hyperplastic thyroid lesions, follicular adenomas, and Hashimoto's thyroiditis may contain cells with clear nuclei resembling those of papillary carcinoma. Papillary carcinomas composed entirely of hyperchromatic cells have been overlooked. The WHO monograph defines papillary carcinoma with focal spindle and giant cell carcinoma components but its clinical behavior is unknown. Papillary carcinoma with an insular pattern that does not show the artifactual separation of the cell nests has been misinterpreted as the solid variant of papillary carcinoma. Papillary microcarcinomas include not only the conventional type and the follicular variants but also the tall cell and columnar cell variants.

Adenocarcinoma, Papillary↗
PubMed2003

Thermal evidence of the invasion of a stingless bee nest by a mammal.

Melipona bicolor, an inhabitant of the Atlantic Rainforest, nidifies in hollows of live or dead trees. In order to study thermoregulation of a nest of this species, a temperature data logger was installed inside a hollow tree. After this, an intruder dug a hole, invaded the nest, and probably consumed its honey, pollen and bees, having remained there during three days. Thermal evidence and its behavior allowed the delimitation of a small number of suspects, which we analyzed here. The intruder was a small mammal, predominantly nocturnal, that takes shelter in burrows, probably the yellow armadillo (Euphractus sexcinctus). Other evidence, if collected immediately after invasion, could precisely indicate precisely the species.

Animals↗
PubMed1998

Gamma oscillations in the entorhinal cortex of the freely behaving rat.

Gamma frequency field oscillations (40-100 Hz) are nested within theta oscillations in the dentate-hilar and CA1-CA3 regions of the hippocampus during exploratory behaviors. These oscillations reflect synchronized synaptic potentials that entrain the discharge of neuronal populations within the approximately 10-25 msec range. Using multisite recordings in freely behaving rats, we examined gamma oscillations within the superficial layers (I-III) of the entorhinal cortex. These oscillations increased in amplitude and regularity in association with entorhinal theta waves. Gamma waves showed an amplitude minimum and reversed in phase near the perisomatic region of layer II, indicating that they represent synchronized synaptic potentials impinging on layer II-III neurons. Theta and gamma oscillations in the entorhinal cortex were coupled with theta and gamma oscillations in the dentate hilar region. The majority of layer II-III neurons discharged irregularly but were phase-related to the negative peak of the local (layer II-III) gamma field oscillation. These findings demonstrate that layer II-III neurons discharge in temporally defined gamma windows (approximately 10-25 msec) coupled to the theta cycle. This transient temporal framework, which emerges in both the entorhinal cortex and the hippocampus, may allow spatially distributed subpopulations to form temporally defined ensembles. We speculate that the theta-gamma pattern in the discharge of these neurons is essential for effective neuronal communication and synaptic plasticity in the perforant pathway.

Animals↗
PubMed1996

A tyrosine kinase-like molecule is localized in the nuclear membrane of neurons: hippocampal behavior under stress.

Protein tyrosine kinases play important roles in the development of the mammalian nervous system during embryogenesis and in the maintenance of function of the adult brain. Using a semi-nested PCR technique based on a short amino acid motif of protein tyrosine kinases, we isolated a human genomic DNA encoding a peptide whose sequence was related to known mammalian protein tyrosine kinases. The expression was examined by Northern blot analysis, and transcripts were detected almost exclusively in the brain. The corresponding cDNA was sequenced, and it was revealed that the gene designated as byk coded for a receptor-like molecule with a motif of protein tyrosine kinase. Immunohistochemical analysis demonstrated that the Byk protein was expressed in neurons and was located in the nuclear envelope. To understand the physiological significance of the Byk protein, we investigated the behavior of this molecule in the hippocampus after ischemia. Byk-like immunoreactivity disappeared from the neurons in the fields CA1 through CA3 and the dentate gyrus of the hippocampus following 20 min of ischemia. After recirculation of blood flow, neurons in the CA3 field and the dentate gyrus re-expressed Byk-like antigen but CA1 neurons did not. Interestingly, Byk-like immunoreactivity was detected in microglial cells and astrocytes in the CA1 field that were activated after ischemia. Byk could be a new tool to study the neuron-glia and glia-glia interactions.

Amino Acid Sequence↗
PubMed1987

The development of thermoregulation after prenatal exposure to alcohol in rats.

The effect of prenatal exposure to alcohol on the development of thermoregulation and behavioral thermogenesis was assessed in rats. Pups at 5, 10, 15, and 20 days of age were chosen from litters with one of three prenatal treatment histories: liquid diet with 35% ethanol-derived-calories (35% EDC), pair-fed control (0% EDC), or lab chow control (LC). Subjects were removed from the home nest and had their initial rectal temperatures recorded before placement alone in the center of an observational chamber in a testing room maintained at 23-24 degrees C. Rectal temperatures were recorded again every hour for the next 4 h. Speed to reach the wall for behavioral thermogenesis (wall-huddling) was also measured at each hourly interval. With increasing age, all pups displayed increasing ability to maintain their initial core temperature, but prenatal exposure to alcohol had a significant effect in retarding the development of thermoregulation. At 5 and 10 days of age, alcohol-exposed pups had significantly lower rectal temperatures at 1-4 h out of the nest compared to control pups. In addition, the speed to reach the wall was slower in 35% EDC pups than in pups from the two control groups, suggesting a deficit in behavioral thermogenesis as well. These results agree with others demonstrating alcohol-induced development delays, and may have implications for other behavioral deficits seen after prenatal exposure to alcohol.

Animals↗
PubMedDate not supplied

[Role of natural sensory factors in organization of feeding behavior using fledgling development as an example].

A change in the composition of natural sensory stimuli, triggers of the alimentary functional system of Muscicapa hypoleuca nestlings, was studied throughout their nest life. In the first five days the alimentary reaction is elicited by a complex of acoustic stimuli. From the fifth to the eighth day the reaction appears in response to a momentary change of illumination. From the ninth to the thirteenth day two stimuli are involved in the organization of the alimentary reaction: a trigger stimulus-a momentary change of illumination, and a directional stimulus-a mobile silhouette of the bird. On the thirteenth to the fifteenth day the alimentary reaction appears only in response to the bird's movement. It is assumed that the successive change of trigger stimuli in one and the same alimentary functional system is determined by a successive involvement of increasingly complicated sensory mechanisms. The time periods of involvement may vary with a change of environmental factors.

Animals↗
PubMed1980

[Life-span-developmental psychology and gerontology (author's transl)].

The recognition that aging processes are considerably influenced by the individuals' life-course from birth on can be traced to antiquity. One of the first attempts of scientific study of the entire life-course was started by Charlotte Bühler (1933). Already in 1951, Thomae emphasized the necessary extension of Developmental Psychology from its restriction to childhood into covering the entire life-span, and initiated numerous empirical studies working with the biographical method. Thus, the "life-span-orientation" of Developmental Psychology, recently ascribed to P.B. Baltes, is rather a rediscovered conceptualization than a genuine 'new' idea. Following this evaluation of the historical roots and origins of "life-span-developmental-psychology", a review of empirical biographical studies is presented, which emphasize a conceptualization of behavior in older age at the intersection of past experience, current situation, and future time perspective of the individual. As an example it is discussed how the mother experiences and reacts to her (last) child's leaving home ("empty-nest-reaction"). In addition, "sociogendtic risk-factors" (Eitner) are discussed, as well as the biographical interdependency of mental and physical activity, of multiple interests and social contacts. Stating the empirical evidence for the strong influence of behavior and experience in younger and middle adulthood on the individual's well-being in older age must not lead to the conclusion that the situation of the aged person cannot be changed: the older individual certainly has the ability and opportunity to learn, to be flexible, and to change--within the given boundaries--his current situation.

Adolescent↗
PubMed1993

Endocrine changes associated with spawning behavior in male kokanee salmon (Oncorhynchus nerka) and the effects of anosmia.

This study examines the relationship between social status, behavioral activity, and hormone levels through the spawning cycle in male kokanee salmon (Oncorhynchus nerka). Shortly after arrival at the spawning grounds, male kokanee undergo dramatic changes in morphological and physiological condition: there is an increase in body depth, a bright silvery appearance is replaced by an intense red coloration, and spermiation commences. Males become associated with nesting females which they defend against other males. The androgens, testosterone and 11-ketotestosterone, decline slowly over the spawning period from high levels observed in the silvery males; gonadotropin (GtH II) and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one increase as males approach final maturation. Androgen and GtH levels in males placed in pens with females over the spawning bed were higher than those in males penned without females. Among males competing for females, amounts of milt and plasma concentrations of GtH were higher in those males that were successful in gaining access to nesting females. A marked reduction in milt and plasma hormones following cauterization of the olfactory nares indicates that olfactory stimuli play a role in mediating endocrine and spermiation responses to the nesting females. Anosmic males were less vigorous and persistent in their courtship, suggesting that, either a female pheromone and/or high levels of hormone are necessary to maintain full reproductive behavior in male kokanee. The role of socially induced hormone changes in modulating reproductive behavior is discussed.

Animals↗
PubMed1994

Retronasal or internasal olfaction can mediate odor-guided behaviors in newborn mice.

Studies of olfactory deprivation have most frequently used unilateral naris occlusion to effect deprivation. Recent psychophysical evidence suggests that adult rodents with either acute or chronic naris occlusion show little decrement in olfactory ability. In this study the effect of naris occlusion coupled with ipsilateral or contralateral olfactory bulb deafferentation on odor-guided behaviors was tested in neonatal mice. Animals that received bilateral bulbectomy or control manipulation were also included. In Experiment 1, olfactory lesions were produced by bulb aspiration on the second day after birth (P2). Daily weight gain, a reliable measure of suckling success, was recorded until P21. In Experiment 2, olfactory lesions consisted of bulb transection on P2. Daily weights were recorded until subjects were P10. Animals with bilateral bulbectomy had the highest mortality rate and slowest growth rate. Both naris occlusion groups grew more slowly than controls but were not significantly different at P5 or P10. They diverged, thereafter, such that at P20 the group with naris occlusion ipsilateral to bulbectomy was similar to controls, while the contralateral group was similar to the bilateral bulbectomy group. In Experiment 2, the weights of the naris occlusion groups diverged by the day after surgery, with the contralateral group suffering the most arrested growth. Behavioral tests were combined from the two experiments for analysis. Subjects were tested at P5 for their ability to find the nipple, at P8 for their ability to find the nest, and at P10 for unwashed vs. washed nipple preferences. Only the contralateral group had a significantly depressed ability to find the nipple, while all lesions groups had a significant but similar decline in nest-finding ability.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗