Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Normal Distribution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1987

Norepinephrine in the interpeduncular nucleus of the rat: normal distribution and the effects of deafferentation.

We used correlative biochemical and histochemical methods to examine (1) the norepinephrine (NE) projection from the paired locus coeruleus (LC) to the midline interpeduncular nucleus (IPN) of the adult rat and (2) the ability of the LC to respond to denervation of their target following removal of noradrenergic afferents (6-hydroxydopamine lesions of the LC) or non-noradrenergic afferents (lesion of the paired fasciculi retroflexi(FR]. Histofluorescence revealed that the NE innervation from the two LC to the IPN is symmetric and overlapping. This projection is confined to rostral, central, and intermediate subnuclei and is absent from lateral and dorsal subnuclei. We found no evidence for homotypic collateral sprouting of undamaged LC neurons into the IPN following unilateral LC lesion. Bilateral LC lesions also did not induce sprouting by NE-containing neurons from other systems (e.g. the superior cervical ganglion or the lateral tegmental group) or from those LC neurons that survived the 6-hydroxydopamine lesion. Histofluorescence following bilateral FR lesions confirmed an earlier observation that apparent hyperinnervation of the IPN by LC afferents is elicited following removal of non-noradrenergic afferents. Measurements of the turnover rate of NE in the IPN of control animals and those that received bilateral FR lesions indicate an increased NE content and increased turnover rate of NE in the IPN of lesioned animals. Taken together these results suggest an increased number of NE terminals and an increase in the activity of tyrosine hydroxylase. No change in NE content or turnover rate was seen in the frontal cortex from these same animals. This is consistent with a target-dependent regulation of heterotypic collateral sprouting.

Animals↗
PubMed1988

Tachykinin binding sites in the interpeduncular nucleus of the rat: normal distribution, postnatal development and the effects of lesions.

Tachykinin binding sites in the basal midbrain were labeled in adult and neonatal rats using 125I-Bolton Hunter (BH) substance P (SP) and 125I-BH eledoisin as ligands. In the adult, binding was very low in the tegmentum and raphe adjacent to the interpeduncular nucleus (IPN). Within the IPN, no binding with either ligand was seen in the target subnuclei of the habenular SP and substance K projections, the lateral subnuclei and the cap of the rostral subnucleus. Labeling with 125I-BH-SP was very light and was restricted primarily to the central subnucleus of the IPN while 125I-BH-eledoisin labeling was very dense over the dorsal, the ventral sector of the rostral, the intermediate and the central subnuclei. Lesions of major afferents to the IPN, the fasciculus retroflexus or the locus coeruleus, had no effect on the distribution or density of the binding of either ligand. In rats 0, 4 or 7 days or age, 125I-BH-SP binding was very dense in the ventral tegmental region, the raphe and in the dorsal, rostral and central subnuclei. 125I-BH-eledoisin binding was extremely dense in the raphe and in the dorsal, rostral, intermediate and central subnuclei but was less dense in the ventral tegmentum. Adult levels of binding in the midbrain were established by 11 days of age. Neonatal lesions restricted to the fasciculus retroflexus had no effect on the density of labeling with either ligand in animals allowed to reach adulthood.

Aging↗
PubMed1986

Esophageal blood flow in the cat. Normal distribution and effects of acid perfusion.

The radioactive microsphere technique was used to estimate blood flow to different regions of the esophagus and to adjacent regions of the stomach before and after perfusion of the esophagus with hydrochloric acid (pH 1.5) for 5 min. Under resting conditions total blood flow, as well as blood flow to the mucosal-submucosal layer and the muscular layer, to both sphincters was significantly higher than to the esophageal body. Blood flow to the adjacent regions of the stomach was significantly higher than esophageal blood flow. Acid perfusion resulted in a large increase in total blood flow in both sphincters and the lower esophageal body. Gastric blood flow was not altered by acid perfusion. The esophageal hyperemia resulted primarily from an increase in blood flow to the muscular layer; mucosal-submucosal blood flow was increased only in the lower esophageal sphincter. The present study indicates that short periods (5 min) of gastroesophageal reflux may increase esophageal blood flow.

Animals↗
PubMed1987

Opiate binding sites in the interpeduncular nucleus of the rat: normal distribution and the effects of fasciculus retroflexus lesions.

Opiate receptors have been localized autoradiographically to many regions of the rat central nervous system. The interpeduncular nucleus has an especially high concentration of these receptors. We used [3H]naloxone and [125I] [D-Ala2,MePhe4,Glyol5]enkephalin as ligands to map the distribution of opiate receptors among the subnuclei of the interpeduncular nucleus. The rostral subnucleus contains label that is densest dorsally. More caudally, high densities of opiate binding sites are found in the lateral, rostral, and central subnuclei. The dorsal subnucleus contains a moderate density of binding sites and the intermediate subnuclei contain almost none. Opiate receptors have also been localized to the medial habenulae and the fasciculi retroflexi, which provide a major afferent input to the interpeduncular nucleus. Lesions of the fasciculi retroflexi decreased the density of opiate binding sites in the rostral and lateral subnuclei of the interpeduncular nucleus. There were no changes seen in the dorsal, intermediate or central subnuclei. These results suggest that a minority of opiate receptors in the interpeduncular nucleus are located presynaptically on fasciculi retroflexi axons. Immunocytochemical studies have demonstrated that the rat interpeduncular nucleus contains substance P, serotonin and enkephalin, and each has a distinct subnuclear distribution. Although the opiate binding sites have a wider distribution than substance P, serotonin, or enkephalin individually, the pattern of opiate binding most closely parallels substance P distribution. The combined distribution of substance P, serotonin, and enkephalin is equivalent to that of the opiate binding sites.

Animals↗
PubMed2005

Plane rectangular tritium target response to excitation by uniform distributed normal accelerated deuteron beam.

This work is a contribution to analytical study of the spatial dependency of the d-T mean neutron energy in the vicinity of a homogeneous tritium-occluded rectangular plane target. An accelerated deuteron beam excites the tritium target with normal incidence to the target plane. The transverse density of accelerated deuteron beam is assumed to be constant close to the target. Due consideration being paid to d-T collision kinetics, depending upon mass and kinetic energy of particles involved in the nuclear collision, nuclear reaction energy, etc, in particular circumstances, the elementary neutron energy emission in non-dispersive media can be considered to be omni-directional or very low anisotropical. Consequently, analytical expressions can be considerably simplified, taking into account the exothermic character of d-T fusion reaction. A number of expressions for energetic prediction of the fast neutron generated, in this case, by d-T reaction are proposed. Animated three-dimensional-graphics is suggested. Computationally tractable tools are of importance in the study of some situations such as induced reactions and activation analysis using 14MeV neutrons, investigations in health-physics, radiation dose characterization, nuclear medicine, damage effects, and simulation studies.

Journal Article↗
PubMed1999

Neuropeptides, nitric oxide synthase and GAP-43 in B4-binding and RT97 immunoreactive primary sensory neurons: normal distribution pattern and changes after peripheral nerve transection and aging.

We have here sought to cross-correlate the expression of immunoreactivities for several neuropeptides, nitric oxide synthase (NOS) and the growth associated protein GAP-43 in subpopulations of dorsal root ganglion (DRG) neurons tagged by the selective markers isolectin B4 and the neurofilament antibody RT97, selective for, respectively, subpopulations of small and large DRG neurons. By use of double- and triple-labeling immunohistochemistry, non-manipulated and sciatic nerve transected young adult rats as well as aged (30-months-old) rats were examined using a confocal microscope equipped with enhanced spectral separation. In young adult rats, the DRG neuron profiles could be divided into three subpopulations (B4 binding (B4+) approximately 50%; RT97-immunoreactive (RT97+) approximately 35%; B4-/RT97- approximately 15%). Calcitonin gene-related peptide (CGRP) is expressed in all three subpopulations. Galanin message-associated peptide (GMAP) colocalize with CGRP (100%) but is not expressed in RT97+ profiles. NOS is present in the RT97- subpopulations and frequently colocalize with CGRP (92%). GAP-43 is expressed in all three DRG subpopulations and colocalize with CGRP (88%), GMAP (38%) and/or NOS (22%). Only very small differences were seen among the young adult rats, implicating that the size of respective subpopulation as well as the expression pattern for neuropeptides, NOS and GAP-43 are fairly stable. Sciatic nerve transection reduced B4-binding but not RT97-like immunoreactivity. Distinct changes in the expression of neuropeptides, NOS and GAP-43 were evident in the DRG subpopulations and, furthermore, the regulatory changes were very similar among the lesioned animals. The relative size of the DRG subpopulations was unaffected by aging, while the expression of neuropeptides was altered showing similarities with the changes induced by axotomy in young adult rats.

Aging↗
PubMed2003

Increased regional cerebral blood flow but normal distribution of GABAA receptor in the visual cortex of subjects with early-onset blindness.

Before the completion of visual development, visual deprivation impairs synaptic elimination in the visual cortex. The purpose of this study was to determine whether the distribution of central benzodiazepine receptor (BZR) is also altered in the visual cortex in subjects with early-onset blindness. Positron emission tomography was carried out with [(15)O]water and [(11)C]flumazenil on six blind subjects and seven sighted controls at rest. We found that the CBF was significantly higher in the visual cortex for the early-onset blind subjects than for the sighted control subjects. However, there was no significant difference in the BZR distribution in the visual cortex for the subject with early-onset blindness than for the sighted control subjects. These results demonstrated that early visual deprivation does not affect the distribution of GABA(A) receptors in the visual cortex with the sensitivity of our measurements. Synaptic elimination may be independent of visual experience in the GABAergic system of the human visual cortex during visual development.

Adult↗
PubMedDate not supplied

Quantitative immuno-electron microscopic analysis of nuclear respiratory factor 2 alpha and beta subunits: Normal distribution and activity-dependent regulation in mammalian visual cortex.

The macaque visual cortex is exquisitely organized into columns, modules, and streams, much of which can be correlated with its metabolic organization revealed by cytochrome oxidase (CO). Plasticity in the adult primate visual system has also been documented by changes in CO activity. Yet, the molecular mechanism of regulating this enzyme remains not well understood. Being one of only four bigenomic enzymes in mammalian cells, the transcriptional regulation of this enzyme necessitates a potential bigenomic coordinator. Nuclear respiratory factor 2 (NRF-2) or GA-binding protein is a transcription factor that may serve such a critical role. The goal of the present study was to determine if the two major subunits of NRF-2, 2alpha and 2beta, had distinct subcellular distribution in neurons of the rat and monkey visual cortex, if major metabolic neuronal types in the macaque exhibited different levels of the two subunits, and if they would respond differently to monocular impulse blockade. Quantitative immuno-electron microscopy was used. In both rats and monkeys, nuclear labeling of alpha and beta subunits was mainly over euchromatin rather than heterochromatin, consistent with their active participation in transcriptional activity. Cytoplasmic labeling was over free ribosomes, the Golgi apparatus, and occasionally the nuclear envelope, signifying sites of synthesis and possible posttranslational modifications. The density of both subunits was much higher in the nucleus than in the cytoplasm for all neurons examined, again indicating that their major sites of cellular action is in the nucleus.

Animals↗
PubMed2006

Characterization of background concentrations of contaminants using a mixture of normal distributions.

We present a Bayesian approach for characterizing background contaminant concentration distributions using data from sites that may have been contaminated. Our method, focused on estimation, resolves several technical problems of the existing methods sanctioned by the U.S. Environmental Protection Agency (USEPA) (a hypothesis testing based method), resulting in a simple and quick procedure for estimating background contaminant concentrations. The proposed Bayesian method is applied to two data sets from a federal facility regulated under the Resource Conservation and Restoration Act. The results are compared to background distributions identified using existing methods recommended by the USEPA. The two data sets represent low and moderate levels of censorship in the data. Although an unbiased estimator is elusive, we show that the proposed Bayesian estimation method will have a smaller bias than the EPA recommended method.

Bayes Theorem↗