bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adherence to repeat screening flexible sigmoidoscopy in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial
Authors: Weissfeld Joel L. , Ling Bruce S. , Schoen Robert E. , Bresalier Robert S. , Riley Thomas , Prorok Philip C. ,   PLCO Project Team
Published: August 2002

AbstractBACKGROUNDAcceptance of screening flexible sigmoidoscopy has been poor, in part because of providers' concerns regarding the acceptability of the procedure. In the current prospective study, the authors used adherence to repeat testing to assess the acceptability of screening flexible sigmoidoscopy.METHODSThe current study was a prospective study of a randomized clinical trial drawing volunteers from the community. Subjects included 10,164 Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial participants who were available for follow‐up 3 years after undergoing a baseline screening flexible sigmoidoscopy examination. The authors measured adherence and identified those factors that appeared to affect adherence to repeat sigmoidoscopy.RESULTSOverall, 18.3% of women and 10.0% of men did not undergo a repeat sigmoidoscopy. Among individuals who attended the Year‐3 clinic, 10.4% of women and 5.1% of men specifically refused repeat sigmoidoscopy when it was offered (risk of refusal in women compared with men, 2.04; 95% confidence interval, 1.76–2.36). Another factor found to be associated with refusal included a technically inadequate baseline sigmoidoscopy.CONCLUSIONSGender and past experiences with sigmoidoscopy may impact adherence to repeat screening. Nonetheless, among research volunteers in a randomized clinical trial of screening, excellent adherence to repeat screening flexible sigmoidoscopy could be achieved. Cancer 2002;94:2569–76. © 2002 American Cancer Society.DOI 10.1002/cncr.10538
Ascending and descending projections of the lateral vestibular nucleus in the frog Rana esculenta
Authors: Matesz Clara , Kulik Akos , Bácskai Timea 
Published: August 2002

AbstractThe lectin Phaseolus vulgaris leucoagglutinin was injected into the frog lateral vestibular nucleus (LVN) to study its antero‐ and retrograde projections. The following new observations were made. 1) In the diencephalon, vestibular efferents innervate the thalamus in a manner similar to that of mammalian species. The projections show a preference for the anterior, central, and ventromedial thalamic nuclei. 2) In the mesencephalon, vestibular fibers terminate in the tegmental nuclei and the nucleus of medial longitudinal fascicle. 3) In the rhombencephalon, commissural and internuclear projections interconnect the vestibular nuclei. Some of the termination areas in the reticular formation can be homologized with the mammalian inferior olive and the nucleus prepositus hypoglossi. Another part of the vestibuloreticular projection may transmit vestibular impulses toward the vegetative centers of the brainstem. A relatively weak projection is detected in the spinal nucleus of the trigeminal nerve, dorsal column nuclei, and nucleus of the solitary tract. 4) In the spinal cord, vestibular terminals are most numerous in the ipsilateral ventral horn and in the triangular area of the dorsal horn. 5) The coincidence of retrogradely labeled cells with vestibular receptive areas suggests reciprocal interconnections between these structures and the LVN. 6) In seven places, the LVN projections overlap the receptive areas of proprioceptive fibers, suggesting a convergence of sensory modalities involved in the sense of balance. J. Comp. Neurol. 444:115–128, 2002. © 2002 Wiley‐Liss, Inc.
Ontogeny of NADPH diaphorase/nitric oxide synthase reactivity in the brain of Xenopus laevis
Authors: López Jesús M. , Gonźlez Agustín 
Published: August 2002

AbstractThe development of nitric oxide synthase (NOS) expression in the brain of Xenopus laevis tadpoles was studied by means of immunohistochemistry using specific antibodies against NOS and enzyme histochemistry for nicotinamide adenine dinucleotide phosphate (NADPH)‐diaphorase. Both techniques yielded identical results and were equally suitable for demonstrating the nitrergic system in the brain. The only mismatches were observed in the olfactory nerve and glomeruli and in the terminal nerve; they were intensely labeled with the NADPH‐diaphorase technique but failed to stain with NOS immunohistochemistry. As early as stage 33, nitrergic cells were observed in the caudal rhombencephalon within the developing inferior reticular nucleus. At later embryonic stages, different sets of reticular and tegmental neurons were labeled in the middle reticular nucleus and, more conspicuously, in the laterodorsal and pedunculopontine tegmental nuclei. As development proceeded, new nitrergic cell groups gradually appeared in the mesencephalon, diencephalon, and telencephalon. A general caudorostral temporal sequence was observed, both in the whole brain and within each main brain subdivision. The premetamorphic period was mainly characterized by the maturation of the cell populations developed in the embryonic period. During prometamorphosis, the nitrergic system reached an enormous development, and many new cell groups were observed for the first time, in particular in the telencephalon. By the climax of metamorphosis, the pattern of organization of nitrergic cells and fibers observed in the brain was similar to that present in the adult brain. Transient expression of NOS was not detected in any brain region. Our data suggest that nitric oxide plays an important role during brain development of Xenopus. Comparison with the developmental pattern of nitrergic systems in other vertebrates shows that amphibians possess more common features with amniotes than with anamniotes. J. Comp. Neurol. 445:59–77, 2002. © 2002 Wiley‐Liss, Inc.
Descending supraspinal pathways in amphibians: III. Development of descending projections to the spinal cord in Xenopus laevis with emphasis on the catecholaminergic inputs
Authors: Sánchez‐Camacho Cristina , Martín Oscar , Ten Donkelaar Hans J. , González Agustín 
Published: August 2002

AbstractIn developmental stages of the clawed toad, Xenopus laevis, we describe the ontogeny of descending supraspinal connections, catecholaminergic projections in particular, by means of retrograde tracing techniques with dextran amines. Already at embryonic stages (stage 40), spinal projections from the reticular formation, raphe nuclei, Mauthner neurons, vestibular nuclei, the locus coeruleus, the interstitial nucleus of the medial longitudinal fasciculus, the posterior tubercle, and the periventricular nucleus of the zona incerta are well developed. At the beginning of the premetamorphic period (stage 46), spinal projections arise from the suprachiasmatic nucleus, the torus semicircularis, the pretectal region, and the ventral telencephalon. After stage 48, tectospinal and cerebellospinal projections develop, with spinal projections from the preoptic area following at stage 51. Rubrospinal projections are present at stage 50. During the prometamorphic period, spinal projections arise in the nucleus of the solitary tract, the lateral line nucleus, and the mesencephalic trigeminal nucleus. With in vitro double‐labeling methods, based on retrograde tracing of dextran amines in combination with tyrosine hydroxylase (TH) immunohistochemistry, we show that at stage 40/41, catecholaminergic (CA) neurons in the posterior tubercle are the first to project to the spinal cord. Subsequently, at stage 43, new projections arise in the periventricular nucleus of the zona incerta and the locus coeruleus. The last CA projection to the spinal cord originates from neurons in the nucleus of the solitary tract at the beginning of prometamorphosis (stage 53). Our data show a temporal, rostrocaudal sequence in the development of the CA cell groups projecting to the spinal cord. Moreover, the early appearance of CA fibers, preterminals and terminal‐like structures in dorsal, intermediate, and ventral zones of the embryonic spinal cord, suggests an important role for catecholamines during development in nociception, autonomic functions, and motor control at the spinal level. J. Comp. Neurol. 446:11–24, 2002. © 2002 Wiley‐Liss, Inc.
Plastic reaction of the rat visual corticocollicular connection after contralateral retinal deafferentiation at the neonatal or adult stage: Axonal growth versus reactive synaptogenesis
Authors: García Del Caño Gontzal , Gerrikagoitia Inmaculada , Martínez‐Millán Luis 
Published: August 2002

AbstractThe effects of neonatal or adult enucleation on the final adult pattern of the rat visual corticocollicular (C‐Co) connection were studied using the anterograde tracer biotinylated dextranamine 10,000 (BDA) iontophoretically injected in the primary visual cortex. In control animals, column‐shaped terminal fields limited to a small portion of the collicular surface were observed. Synaptic boutons were present in all superficial strata of the superior colliculus (SC), with the highest density in the ventral part of the stratum griseum superficiale (SGS). Neonatal enucleation caused a considerable expansion of the contralateral visual C‐Co terminal fields, which occupied almost the entire collicular surface, suggesting that axonal sprouting had occurred. In addition, terminal boutons tended to localize more dorsally in these cases compared with controls. Following enucleation in adult animals, no changes were observed with respect to the extension of the terminal fields, although a plastic reaction leading to an increase in the bouton density in the stratum zonale (SZ) and upper SGS was found, reflecting a process of reactive synaptogenesis at these levels. These results show that both neonatal and adult visual C‐Co fibers react in response to retinal ablation, although this reaction shows distinct characteristics. Molecular factors, such as growth‐associated cytoskeletal proteins operating in the cortical origin, and extracellular matrix components and myelin‐associated axonal growth inhibitors acting on the collicular target very likely account for these differences. J. Comp. Neurol. 446:166–178, 2002. © 2002 Wiley‐Liss, Inc.
Synaptic distribution of ionotropic glutamate receptors in the inner plexiform layer of the primate retina
Authors: Grünert Ulrike , Haverkamp Silke , Fletcher Erica L. , Wässle Heinz 
Published: August 2002

AbstractThe distribution and synaptic clustering of glutamate receptors (GluRs) were studied in the inner plexiform layer (IPL) of the macaque monkey retina by using subunit specific antisera. A punctate immunofluorescence pattern was observed in the IPL for all subunits tested, and electron microscopy confirmed that the immunoreactive puncta represent clustering of receptors at sites postsynaptic to the bipolar cell ribbon synapses (dyads). Usually only one of the two postsynaptic processes at the dyads expressed a given subunit. Immunoreactive GluR2, GluR2/3, and GluR4 puncta were found at high density throughout the IPL and are probably expressed at every dyad. The GluR1 subunit was expressed at lower density. The N‐methyl‐D‐aspartate (NMDA) receptor subunits NR2A and NR1C2′ were restricted to synapses localized in two broad bands in the center of the IPL. They were often colocalized with GluR2/3 and GluR4 subunits. The orphan receptor subunits δ1/2 predominated in three horizontal bands. The kainate receptor subunits GluR6/7 were clustered in large postsynaptic densities adjacent to bipolar cell axon terminals but lacking a synaptic ribbon on the presynaptic side. This might represent a conventional synapse made by a bipolar axon terminal. The results suggest that GluR2/3 and GluR4, together with NMDA receptors, are preferentially expressed on ganglion cell dendrites, whereas kainate receptors and the δ1/2 subunits are mostly localized on amacrine cell processes. J. Comp. Neurol. 447:138–151, 2002. © 2002 Wiley‐Liss, Inc.
Localization of kainate receptors at the cone pedicles of the primate retina
Authors: Haverkamp Silke , Grünert Ulrike , Wässle Heinz 
Published: August 2002

AbstractIn the macaque monkey retina cone pedicles, the output synapses of cone photoreceptors, contain between 20 and 45 ribbon synapses (triads), which are the release sites for glutamate, the cone transmitter. Several hundred postsynaptic dendrites contact individual cone pedicles, and we studied the glutamate receptors expressed and clustered at these contacts, particularly the kainate receptor subunits GluR5, GluR6/7, and KA2. Pre‐ and postembedding immunocytochemistry and electron microscopy were used to localize GluR5 and GluR6/7 to specific synaptic contacts at the cone pedicle base. The GluR5 subunit was aggregated at bipolar cell flat contacts. The GluR6/7 subunit was aggregated at bipolar cell flat contacts and at the desmosome‐like junctions formed by horizontal cell processes underneath the cone pedicles. KA2 immunoreactivity was observed at the invaginating dendritic tips of ON‐cone and rod bipolar cells, which we interpret as a cross‐reactivity of the KA2 antiserum with some other, unknown protein of the monkey retina. Kainate receptors are preferentially expressed by OFF‐cone bipolar cells and to a lesser extent by horizontal cells. We also performed double‐labeling experiments with the ribbon‐specific marker bassoon and with antibodies against GluR5 and GluR6/7 in order to define the position of the flat bipolar cell contacts with respect to the triads. There was a tendency of GluR6/7 clusters to represent triad‐associated contacts, whereas GluR5 clusters represented non‐triad‐associated contacts. The GluR5 and GluR6/7 subunits were clustered at different bipolar cell contacts. We studied a possible cone‐selective expression of the kainate receptor subunits by double labeling cone pedicles for the S‐cone opsin and for the different receptor subunits. We observed a reduced expression of both GluR5 and GluR6/7 at the S‐cone pedicles. The reduced expression of GluR6/7 was analyzed in more detail and it appears to be a consequence of a horizontal cell‐specific expression: H1 horizontal cells express GluR6/7, whereas H2 horizontal cells, which preferentially innervate S‐cones, show no expression of GluR6/7. J. Comp. Neurol. 436:471–486, 2001. © 2001 Wiley‐Liss, Inc.
Colocalization of GABA and glycine in the ventral nucleus of the lateral lemniscus in rat: An in situ hybridization and semiquantitative immunocytochemical study
Authors: Riquelme Raquel , Saldaña Enrique , Osen Kirsten K. , Ottersen Ole P. , Merchán Miguel A. 
Published: August 2002

AbstractWe have studied by in situ hybridization for GAD65 mRNA in thick sections and by semiquantitative postembedding immunocytochemistry in consecutive semithin sections, the expression of γ‐aminobutyric acid (GABA) and glycine in cell bodies and axosomatic puncta of the rat ventral nucleus of the lateral lemniscus (VNLL), a prominent monaural brainstem auditory structure. The in situ hybridization and the densitometric analysis of the immunostaining suggest that the rat VNLL contains two main populations of neurons. Approximately one‐third of neurons are unstained with either technique and are presumably excitatory; their cell bodies are enveloped by a large number of glycine‐immunoreactive puncta. Most if not all of the remaining two‐thirds colocalize GABA and glycine and are assumed to be inhibitory. These two populations show a complementary distribution within the VNLL, with inhibitory neurons located mainly ventrally and excitatory neurons dorsally. In scatterplots of gray values measured from cell bodies, the double‐labeled cells appear to form a single cluster in terms of their staining intensities for the two transmitter candidates. However, this cluster may have to be further subdivided because cells with extreme GABA/glycine ratios differ from those with average ratios with respect to location or size. The VNLL seems unique among auditory structures by its large number of neurons that colocalize GABA and glycine. Although the functional significance of this colocalization remains unknown, our results suggest that the VNLL exerts convergent excitatory and inhibitory influences over the inferior colliculus, which may underlie the timing processing in the auditory midbrain. J. Comp. Neurol. 432:409–424, 2001. © 2001 Wiley‐Liss, Inc.
Descending supraspinal pathways in amphibians. I. A dextran amine tracing study of their cells of origin
Authors: Sánchez‐Camacho Cristina , Marín Oscar , Ten Donkelaar Hans J. , González Agustín 
Published: August 2002

AbstractThe present study is the first of a series on descending supraspinal pathways in amphibians in which hodologic and developmental aspects are studied. Representative species of anurans (the green frog, Rana perezi, and the clawed toad, Xenopus laevis), urodeles (the Iberian ribbed newt, Pleurodeles waltl), and gymnophionans (the Mexican caecilian, Dermophis mexicanus) have been used. By means of retrograde tracing with dextran amines, previous data in anurans were largely confirmed and extended, but the studies in P. waltl and D. mexicanus present the first detailed data on descending pathways to the spinal cord in urodeles and gymnophionans. In all three orders, extensive brainstem‐spinal pathways were present with only minor representation of spinal projections originating in forebrain regions. In the rhombencephalon, spinal projections arise from the reticular formation, several parts of the octavolateral area, the locus coeruleus, the laterodorsal tegmental nucleus, the raphe nucleus, sensory nuclei (trigeminal sensory nuclei and the dorsal column nucleus), and the nucleus of the solitary tract. In all species studied, the cerebellar nucleus and scattered cerebellar cells innervate the spinal cord, predominantly contralaterally. Mesencephalic projections include modest tectospinal projections, torospinal projections, and extensive tegmentospinal projections. The tegmentospinal projections include projections from the nucleus of Edinger‐Westphal, the red nucleus, and from anterodorsal, anteroventral, and posteroventral tegmental nuclei. In the forebrain, diencephalospinal projections originate in the ventral thalamus, posterior tubercle, the pretectal region, and the interstitial nucleus of the fasciculus longitudinalis medialis. The most rostrally located cells of origin of descending spinal pathways were found in the suprachiasmatic nucleus, the preoptic area and a subpallial region in the caudal telencephalic hemisphere, probably belonging to the amygdaloid complex. Our data are discussed in an evolutionary perspective. J. Comp. Neurol. 434:186–208, 2001. © 2001 Wiley‐Liss, Inc.
Co‐expression of estrogen and thyroid hormone receptors in individual hypothalamic neurons
Authors: Kia Hosein Kami , Krebs Christopher J. , Koibuchi Noriyuki , Chin William W. , Pfaff Donald W. 
Published: August 2002

AbstractEstrogen receptors (ER) and thyroid hormone receptors (TR) are members of the nuclear receptor family of transcription factors that induce or repress the expression of target genes. Previous behavioral studies in female rodents have demonstrated that thyroid hormones can antagonize the effects of estrogen in the central nervous system (CNS), particularly by attenuating estrogen’s ability to facilitate reproductive behaviors. Additional molecular studies have suggested a mechanism for this antagonism by showing that ligand‐activated ERα and TRs have the potential to interact in their transcriptional controls. Although the expression patterns of ERα and TRs in the rodent brain appear to overlap in behaviorally relevant areas, it remained to be determined whether these two classes of proteins coexist in vivo at the level of single neurons. To address this possibility, we employed a highly sensitive double‐label in situ hybridization technique using digoxigenin and 35S‐labeled cRNA probes to analyze, in detail, the expression of ERα mRNA with TRα1 and TRα2 mRNAs in the same neurons of the ovariectomized (OVX) adult mouse brain. Our results demonstrate that a large majority of the ERα‐positive neurons also expresses TRα1 and TRα2 mRNAs. Quantitative examination of the cellular expression in the ventromedial and arcuate nuclei of the hypothalamus (VMH and Arc) showed that 81.5% and 80.5% of the neurons endowed with ERα mRNA also contain TRα1 and TRα2 mRNAs, respectively. In the amygdala, more than 60.5% and 67% of ERα‐positive cells also contain TRα1 and TRα2 mRNAs, respectively. These findings provide the first anatomical evidence that ER and TR can be found in the same neurons, including hypothalamic neurons. This coexpression of ERα and TR provides the cellular basis for a new level of neuronal integration in a brain region where estrogens control female reproductive behaviors. J. Comp. Neurol. 437:286–295, 2001. © 2001 Wiley‐Liss, Inc.
Development of three distinct GnRH neuron populations expressing two different GnRH forms in the brain of the African catfish (Clarias gariepinus)
Authors: Dubois Eline A. , Zandbergen Matthijs A. , Peute Jan , Bogerd Jan , Goos Henk J. Th. 
Published: August 2002

AbstractThe early development of both the catfish gonadotropin‐releasing hormone (cfGnRH)‐ and the chicken GnRH‐II (cGnRH‐II) system was investigated in African catfish by immunocytochemistry by using antibodies against the GnRH‐associated peptide (GAP) of the respective preprohormones. Weakly cfGnRH‐immunoreactive (ir) neurons and fibers were present at 2 weeks after hatching (ph) but only in the ventral telencephalon and pituitary. Two weeks later, cfGnRH fibers and neurons were also observed in more rostral and in more caudal brain areas, mainly in the preoptic area and hypothalamus. Based on differences in temporal, spatial, and morphologic appearance, two distinct cfGnRH populations were identified in the ventral forebrain: a population innervating the pituitary (ventral forebrain system) and a so‐called terminal nerve (TN) population. DiI tracing studies revealed that the TN population has no neuronal connections with the pituitary. The cGnRH‐II system is present from 2 weeks ph onward in the midbrain tegmentum and only their size and staining intensity increased during development. Based on the comparison of GnRH systems amongst vertebrates, we hypothesize that during fish evolution, three different GnRH systems evolved, each expressing their own molecular form: the cGnRH‐II system in the midbrain, a hypophysiotropic GnRH system in the hypothalamus with a species‐specific GnRH form, and a salmon GnRH‐expressing TN population. This hypothesis is supported by phylogenetic analysis of known GnRH precursor amino acid sequences. We hypothesize, because the African catfish is a less advanced teleost species, that it contains the cfGnRH form both in the ventral forebrain system and in the TN population.J. Comp. Neurol. 437:308–320, 2001. © 2001 Wiley‐Liss, Inc.