An analysis of comprehensive health promotion programs' consistency with the systems model of health

Purpose. The purpose of this article is to report a review and analysis of the concordance between current comprehensive corporate health promotion programs as described in the published literature and the systems model of health and to explore emerging trends in the field of health promotion. Search Methods. MEDLINE, BIOSIS, and PsycINFO searches were conducted from 1985 to 1991, and the bibliographies of articles thus obtained were back searched for additional descriptions of corporate health promotion programs. Inclusive criteria included "comprehensive" corporate programs, published in peer-reviewed journals or books, and descriptions adequate enough to permit coding in the majority of analysis matrix categories. Out of 63 identified programs, 16 met the inclusion criteria; 47 were excluded. A common reason for rejection was the limitation imposed by inadequate program descriptions in the published literature. Major Findings. On average, the comprehensive corporate programs reviewed were initiated between 1984 and 1987 and set in the context of a manufacturing firm with over 10,000 employees. A minority of programs (12.5%) consistently satisfied systems model criteria. The most common category of programs were those which were inconsistent (44%), meeting some of the criteria of a systems model of health promotion, but not all. The mechanistic medical and public health models predominated strongly (63%) with the preeminent goal being individual risk factor modification. Conclusions. The limitations of the published literature do not permit strong conclusions about the number or degree to which current corporate comprehensive programs are concordant with the systems model of health. Although mechanistic models of health predominated, there is evidence that a number of comprehensive programs were inconsistent with the mechanistic model, meeting some of the criteria, but also meeting some systems model criteria. To continue the advancement of health promotion with clarity and focus, further research is needed to clarify outcomes across different "world view" models of health promotion. Health promotion specialists need to carefully scrutinize programs emanating from different "world view" models as they design, develop, implement, and evaluate corporate programs.

Distribution of noradrenaline-immunoreactivity in the brain of the mormyrid teleost Gnathonemus petersii

The distribution of noradrenaline-immunoreactivity in the brain of the mormyrid fish Gnathonemus petersii was studied in order to evaluate the noradrenergic innervation of a number of specialized mormyrid brain regions, including electrosensory centers and a gigantocerebellum. Noradrenaline-immunoreactive (NAi) neurons occur in the hypothalamic paraventricular organ (PVO), the locus coeruleus, and the caudal rhombencephalon. In the PVO, NAi cerebrospinal fluid (CSF)-contacting neurons are located in the same regions where dopamine- and serotonin-containing CSF contacting neurons occur. The locus coeruleus consists, on each side, of at least 30 rather large NAi neurons with ventrolaterally directed dendrites and dorsolaterally coursing axons. In the caudal rhombencephalon, NAi neurons are located in the transition region between the ventromedial motor zone and the dorsolateral sensory zone. The density of NAi fibers is very high in the efferent tract of the locus coeruleus, the medial forebrain bundle, and two telencephalic, one preoptic, and one rhombencephalic subependymal axonal plexus. A marked NAi innervation is present in the dorsomedial and ventral telencephalon, the preoptic region, periventricular hypothalamic and thalamic regions, the midbrain tectum, cerebellar granular layers, the electrosensory lateral line lobe, the rhombencephalic transition region between the sensory and motor zones, and the area postrema. Other regions are more sparsely innervated by NAi fibers, but regions completely devoid of NAi fibers were not observed. Interestingly, NAi fibers form large club endings in some subdivisions of the precerebellar nucleus lateralis valvulae, and parallel fibers in the cerebellar granular layer. Comparison with the distribution of NAi or dopamine-beta-hydroxylase-immunoreactivity in other species shows that all teleosts studied to date have noradrenergic cells in the locus coeruleus and the caudal rhombencephalon. However, NAi CSF-contacting PVO cells have been described only in the teleost Gnathonemus petersii and the lizard Gekko gecko (Smeets and Steinbusch: J. Comp. Neurol. 285:453-466, '89). It is possible that they might pick up catecholamines as well as serotonin from the CSF, into which monoamines might be released by telencephalic and preoptic subependymal axonal plexuses.

The hypothalamic aggression region of the rat: observations on the synaptic organization

Comparison of detailed physiological and morphological data shows that the hypothalamic aggression region in the rat largely coincides with the intermediate hypothalamic area. This region has a neuronal density of about 35.10(3) neurons per mm3, a synaptic density of about 300.10(6) per mm3, and a synapse to neuron ratio of about 9000, including only about 200 axosomatic synaptic contacts per neuron. Septal synaptic contacts in this region originate from unmyelinated axons and are axodendritic of the asymmetrical type, with an average bouton diameter of 785 nm and an average synaptic contact length of 270 nm.

Why run parallel fibers parallel? Teleostean Purkinje cells as possible coincidence detectors, in a timing device subserving spatial coding of temporal differences

The present paper explores the possible functional significance of the parallel orientation of parallel fibers in teleostean cerebellar and cerebelloid molecular layers, taking advantage of the restricted width of these molecular layers compared with mammalian ones and several specific configurations of granule cells. These configurations include: (i) a unilateral location, i.e. at only one (lateral) side of the molecular layer, giving rise to parallel fibers without bifurcation in a unidirectional molecular layer, where all parallel fibers conduct signals in the same direction; (ii) a bilateral location at both sides of the molecular layer giving rise to a bidirectional molecular layer where parallel fibers conduct signals in two opposite directions originating from two discrete sources; and (iii) a basal (or sometimes apical) location underneath (or opposite to) the layer of Purkinje cells, giving rise to a bidirectional molecular layer where parallel fibers conduct signals in two opposite directions originating from a continuous range of sources. It is argued that molecular layers with a bilateral location of granule cells, exemplified by the mormyrid lobus transitorius, represent an optimal configuration for the analysis of small temporal differences (up to 4 ms) between inputs to the right and left granule cell mass, by means of detection of the site of coincidence of parallel fiber activity running from left to right and vice versa. Morphological aspects that probably optimize such a function include not only the parallel course and bilateral origin of parallel fibers, but also their small diameter, large number and co-extensive location, as well as the sagittal orientation and the presence of many spines of Purkinje cell dendrites and the presence of stellate and other inhibitory interneurons. The only assumption underlying the present coincidence detection hypothesis is that Purkinje cells are supposed to be maximally stimulated by parallel fiber input when all spines are activated in such a way that their excitatory postsynaptic potentials reach the axon hillock simultaneously. For molecular layers with a unilateral location of granule cells, exemplified by the teleostean torus longitudinalis-tectal marginal parallel fiber system, a similar coincidence detecting mechanism is proposed on the basis of the presence of two populations of parallel fibers with slightly different conduction velocities. Such a system might be suitable to adapt the location of coincidence peaks to topographic maps present in deeper layers of nervous tissue. Molecular layers with basally (or apically) located granule cells as encountered in the teleostean corpus cerebelli, are probably involved in the analysis of specific spatio-temporal input waves directed centripetally towards different Purkinje cells.(ABSTRACT TRUNCATED AT 400 WORDS)

An intriguing pitfall in chemical neuroanatomy: specific populations of unspecifically immunoreactive neurons in the brain of the mormyrid fish Gnathonemus petersii

The present paper describes the location, morphology, ultrastructure and immunocytochemical properties of neurons in the brain of the mormyrid fish Gnathonemus petersii, that appear to be unspecifically immunoreactive to a number of secondary or tertiary antibodies used in immunohistochemical procedures, including rabbit-anti-mouse immunoglobulins (IGGs), rabbit peroxidase-anti-peroxidase IGGs, and rabbit-anti-sheep or sheep peroxidase-anti-peroxidase IGGs. Unspecifically immunoreactive (UI) cells have typically neuronal morphological and ultrastructural characteristics, and occur at four specific locations in the mormyrid brain. A small rhombencephalic group is located rostrolateral to the efferent octaval nucleus, between the fasciculus longitudinalis medialis and the decussation of the lateral lemniscus. A mesencephalic cluster of cells is located in the dorsal midbrain tegmentum against the tractus telencephalo-mesencephalicus. In addition, dispersed UI neurons were observed in the nucleus lateralis of the torus semicircularis and in the preoptic region above the optic chiasm. Remarkably, UI cells are clearly present in a substantial number of brains investigated, but not detectable in others. The present findings point to a curious pitfall in chemical neuroanatomy, the functional significance of which is unknown at present. In several previous studies using the brain of G. petersii, UI cells were abusively included in the description of monoaminergic cell groups. Similar cells have until now not been reported in other vertebrate brains.

Distribution of zebrin II in the gigantocerebellum of the mormyrid fish Gnathonemus petersii compared with other teleosts

Immunocytochemistry has demonstrated unexpected heterogeneity among cerebellar Purkinje cells. For example, monoclonal antibody Mab anti-zebrin II reveals parasagittal bands of immunoreactive Purkinje cells in the mammalian cerebellum, but reveals a non-sagittal cerebellar compartmentation pattern in goldfish and gymnotiform fish. The present paper investigates the cerebellar compartmentation pattern, as reflected in the zebrin II distribution, in two other teleosts, the electric mormyrid fish Gnathonemus petersii with its large and regularly built gigantocerebellum, and the electrosensory osteoglossomorph teleost Xenomystis nigri, by using light as well as electron microscopic immunohistochemical techniques. Zebrin II is expressed only in Purkinje cells, where it is present in the cytoplasm of all neuronal compartments, including spines, distal and proximal dendrites, the cell body, and the initial part, as well as terminal boutons of the axon. Other types of cerebellar neurons, including the eurydendroid projection neurons, are zebrin II-negative. In Gnathonemus, zebrin II-positive Purkinje cells are present in the large caudolateral part of the valvula, in lobes C2, C3, and C4 of the corpus, and in the anterior as well as the posterior part of the caudal cerebellar lobe. Zebrin II-negative Purkinje cells are present in a continuous region encompassing the rostromedial part of the valvula, the lobus transitorius, lobe C1 and the ventral part of lobe C2, and in a small, lateral zone of the posterior part of the caudal lobe. In Xenomystis, all Purkinje cells, including those in the medial valvula and the posterior part of the caudal lobe, appear to react with mab anti-zebrin II. This more widespread distribution may be due to the presence of a second antigenic polypeptide in this species. On the basis of the present findings, it is concluded that the mormyrid lobus transitorius, lobe C1, and the ventral part of lobe C2 probably belong to the valvula, while the corpus is restricted to the dorsal part of lobe C2, lobe C3, and lobe C4. The functional significance of zebrin II expression for different subsets of teleostean Purkinje cells remains unclear, since comparisons of different teleosts reveal no general correlation with particular afferent or efferent connections, nor with special morphological features such as a dendritic palisade pattern or different arrangements of the Purkinje cell bodies. A comparison between mammals and teleosts suggests that a distinct parasagittal cerebellar zonation in teleosts is absent, and the major part of the teleostean cerebellum may be considered as a single (midsagittal) cerebellar zone, with about the same width as one mammalian parasagittal zone.

Dendritic and synaptic properties of collicular neurons: a quantitative light and electron microscopical study of Golgi-impregnated cells

The present study deals with a light- and electron microscopic morphometric analysis of Golgi-impregnated neurons in the superior colliculus of rats with the purpose to unravel inter- and intralaminar differences in their dendritic and synaptic organization. In particular, layer IV was studied and compared with its boundary layers III and V. The results show that collicular cells in layer IV basically form a homogeneous population with respect to the number of primary dendrites, the total length of impregnated dendrites, and the diameter, ellipticity, and orientation of dendritic fields and somata of Golgi-impregnated neurons. Somata of reconstructed small cells in layer III and IV as well as V have all a similar density of about 40 synaptic contacts per 100 microns2 surface. However, the cell bodies of large multipolar cells in layer V have a slightly but significantly larger synaptic density (about 50 per 100 microns2). Dendrites of large and small collicular cells had no significantly different synaptic densities (43 and 48 per 100 microns2, respectively). In conclusion, the present results show only minor dendritic and synaptic differences between individual cells in the same layer, as well as in neighboring layers, which implies a low degree of cellular and synaptic intra- and interlaminar differentiation. It is discussed that this organization differs markedly from that in other visual centers, including the collicular homologue, the tectum of lower vertebrates, and the mammalian visual cortex, where pronounced inter- and intralaminar differentiations exist. Such an organization may provide a framework of laminar specificity by which distinct cell types may select a restricted set of input out of all information available. The present quantitative investigation suggests that a similar framework is not present in the superior colliculus.

Palisade pattern of mormyrid Purkinje cells: a correlated light and electron microscopic study

The present study is devoted to a detailed analysis of the structural and synaptic organization of mormyrid Purkinje cells in order to evaluate the possible functional significance of their dendritic palisade pattern. For this purpose, the properties of Golgi-impregnated as well as unimpregnated Purkinje cells in lobe C1 and C3 of the cerebellum of Gnathonemus petersii were light and electron microscopically analyzed, quantified, reconstructed, and mutually compared. Special attention was paid to the degree of regularity of their dendritic trees, their relations with Bergmann glia, and the distribution and numerical properties of their synaptic connections with parallel fibers, stellate cells, "climbing" fibers, and Purkinje axonal boutons. The highest degree of palisade specialization was encountered in lobe C1, where Purkinje cells have on average 50 palisade dendrites with a very regular distribution in a sagittal plane. Their spine density decreases from superficial to deep (from 14 to 6 per micron dendritic length), a gradient correlated with a decreasing parallel fiber density but an increasing parallel fiber diameter. Each Purkinje cell makes on average 75,000 synaptic contacts with parallel fibers, some of which are rather coarse (0.45 microns), and provided with numerous short collaterals. Climbing fibers do not climb, since their synaptic contacts are restricted to the ganglionic layer (i.e., the layer of Purkinje and eurydendroid projection cells), where they make about 130 synaptic contacts per cell with 2 or 3 clusters of thorns on the proximal dendrites. These clusters contain also a type of "shunting" elements that make desmosome-like junctions with both the climbing fiber boutons and the necks of the thorns. The axons of Purkinje cells in lobe C1 make small terminal arborizations, with about 20 boutons, that may be substantially (up to 500 microns) displaced rostrally or caudally with respect to the soma. Purkinje axonal boutons were observed to make synaptic contacts with eurydendroid projection cells and with the proximal dendritic and somatic receptive surface of Purkinje cells, where about 15 randomly distributed boutons per neuron occur. The organization of Purkinje cells in lobe C3 differs markedly from that in C1 and seems to be less regular and specialized, although the overall palisade pattern is even more regular than in lobe C1 because of the absence of large eurydendroid neurons. However, individual neurons have a less regular dendritic tree, there is no apical-basal gradient in spine density or parallel fiber density and diameter, and there are no "shunting" elements in the climbing fiber glomeruli.(ABSTRACT TRUNCATED AT 400 WORDS)

Synaptic morphometry and synapse-to-neuron ratios in the superior colliculus of albino rats

The superior colliculus of mammals is generally divided into seven layers on the basis of the distribution of myelinated fibers, which are densely packed in layers III, V, and VII but sparse in the other layers. The laminar distribution of afferents and efferents allows, in addition, for the distinction of a superficial visual zone (layers I-III) and a deeper multimodal and premotor zone (layers IV-VII). Collicular neurons, however, do not show a lamination pattern, but are rather homogeneously distributed with only gradual transitions (Albers et al.: J. Comp. Neurol. 274:357-370, '88). The present study analyses whether the distribution of collicular synapses is correlated with the laminar organization of collicular axons or rather with the more homogeneous distribution of collicular neurons. For this purpose, the size and density of synaptic terminals and contacts as well as synapse-to-neuron ratios were determined in all collicular layers of albino rats by means of quantitative analysis of electron microscopic pictures. The size of presynaptic terminals and contacts does not differ significantly between individual collicular layers. On average, presynaptic terminal diameter is 1,079 nm, and synaptic contact size 338 nm, while 23% of all contacts are of the symmetrical type with pleiomorphic vesicles. The average numerical synaptic density is 422 million per mm3. This value is significantly higher in layers I and II (on average 670 million per mm3) than in layers III-VII (on average 370 million per mm3). The synapse-to-neuron (S/N) ratios calculated show that collicular neurons have on average 6,120 synaptic contacts on their receptive surface. The S/N ratio is lowest in layer III (4,330), while this ratio is highest in layers I and VII (i.e., 8,970 and 8,560 respectively). Layer II has a significantly higher S/N ratio than layer III (i.e., 8,060 and 4,330, respectively). Our results show that the size of synaptic terminals and contacts is not correlated with the different connectivity patterns of the distinct collicular layers. However, the density of synapses as well as the synapse-to-neuron ratios show a certain degree of laminar differentiation. In particular the superficial visual zone appears to be inhomogeneous in this respect, since layers I and II have a significantly higher density of synapses and higher S/N ratios than layer III. The deeper collicular zone is more homogeneously organized with synaptic densities similar to that of layer III and gradually increasing synapse-to-neuron ratios from layer IV to layer VII.

Different requirements for formation of Jun: Jun and Jun: Fos complexes

The cFos proto-oncoprotein associates with cJun to form a heterodimer with increased DNA binding and transcriptional activities. It has been suggested that dimerization of these proteins is mediated by the interdigitation of an orderly repeat of leucine residues forming a leucine zipper. In agreement with this model, we find that binding to the AP-1 site requires dimerization of these proteins. Although cFos, itself, does not seem to dimerize and bind to the AP-1 site, Jun: Fos heterodimers have higher stability than Jun homodimers, which accounts for their increased DNA binding activity. Mutational analysis indicates that at least three of the repeated leucines of cJun are important for homodimer formation. However, these residues can be mutated without affecting formation of Jun: Fos heterodimers. In addition, several other residues present between the leucines are also important for both homo- and heterodimerization. These findings provide support for the recent proposal that these proteins dimerize via formation of a coiled coil and suggest that residues other than leucines provide specificity for this interaction. Assuming that dimerization is required for proper alignment of the DNA recognition sites, we generated a cJun mutant containing a small insertion between the dimerization and the DNA recognition domains. This mutant fails to bind DNA, but it acts as a trans-dominant inhibitor of cJun and cFos because it still dimerizes with the wild-type proteins.

Distribution of dopamine immunoreactivity in the brain of the mormyrid teleost Gnathonemus petersii

The distribution of dopamine-containing cell bodies and fibers was studied with aid of specific antibodies against dopamine in the highly developed brain of the weakly electric fish Gnathonemus petersii. In the telencephalon, dopamine-containing cell bodies were observed in a small area, i.e., area ventralis pars dorsalis and supracommissuralis. In the diencephalon, moderate numbers of dispersed dopamine-immunoreactive cells were present in the preoptic region, while large numbers of dopamine-containing neurons occurred in the hypothalamic paraventricular organ and neighbouring regions. The paraventricular organ, located around small (anterior, intermediate, and posterior) recesses contained many dopamine-immunoreactive cerebrospinal fluid-(CSF)-contacting neurons. Dopamine-containing cells were also observed in a magnocellular hypothalamic cell group, in the nucleus of the lateral recess, and in the nucleus posterior tuberis. In the mesencephalon only a few dopamine-containing cells were observed in a dorsal tegmental (possibly pretectal) area, whereas in ventral mesencephalic regions dopamine-containing cells were lacking. More caudally, dopamine-containing cells were observed in the presumed locus coeruleus, in the caudal region of the reticular formation, and in the presumed area postrema. Dopamine-immunoreactive fiber density was very high in the medioventral hypothalamus and in the preoptic region, where a dense subependymal plexus was observed along the preoptic recess. Such a plexus was also present in the caudal rhombencephalon, where it probably arises from the area postrema. Moderate numbers of dopamine-immunoreactive fibers were present in medioventral parts of the brain along its total rostrocaudal extent as well as in several subnuclei of the torus semicircularis, in the tectum mesencephali, and in the medial part of the dorsal telencephalic area. Other parts of the dorsal telencephalic area, as well as the large cerebellum and the electrosensory lateral line lobe of Gnathonemus, did not contain detectable amounts of dopamine. In spite of the high differentiation of the brain of Gnathonemus, the distribution of catecholamines as visualized with dopamine immunohistochemistry appears to be basically similar to that described in other teleostean and actinopterygian fishes on the basis of formaldehyde-induced fluorescence or tyrosine hydroxylase immunohistochemistry.(ABSTRACT TRUNCATED AT 400 WORDS)

Distribution of serotonin in the brain of the mormyrid teleost Gnathonemus petersii

The distribution of serotonin-immunoreactive neurons and fibers was studied in the highly developed brain of the weakly electric fish Gnathonemus petersii with the aid of specific antibodies against serotonin. Serotoninergic cell bodies occur in three regions: the raphe region of the brainstem, the hypothalamus, and the transition zone between the dorsal thalamus and the pretectum. Serotoninergic raphe neurons are clustered in three groups: nucleus raphes superior, intermedius, and inferior. The latter has not been described in other teleosts and thus might be the source of the serotoninergic innervation of specific mormyrid electrosensory brain regions. Most hypothalamic serotoninergic neurons have cerebrospinal-fluid (CSF)-contacting processes and thus belong to the paraventricular organ (PVO), which in Gnathonemus is located around a number of small infundibular recesses. The distribution of serotonin in the PVO precisely matches the distribution of dopamine, as described previously. Serotoninergic cells in the thalamopretectal transition zone also have been described in other teleosts, but not in other vertebrate groups, and thus seem to represent a teleostean specialization. Serotoninergic fiber density is especially high in the medial forebrain bundle and surrounding preoptic and hypothalamic regions as well as in several telencephalic and preoptic subependymal plexus. Serotoninergic fibers appear to be almost completely absent in the large and differentiated corpus and valvula cerebelli. Comparison with the literature on teleostean serotoninergic innervation patterns reveals several mormyrid specializations, including the absence of serotonin in large parts of the mormyrid telencephalic lobes, a differentiated innervation pattern of distinct electrosensory and mechanosensory subnuclei of the torus semicircularis, a refined serotoninergic lamination pattern in the midbrain tectum, and a prominent innervation of the electrosensory lateral line lobe, the associated caudal cerebellar lobe, and the electromotor medullary relay nucleus. A distinct innervation of several types of (pre)motor neurons, such as the Mauthner cells and facial motor neurons, has not been reported previously for other teleosts. Consequently, the distribution of serotoninergic fibers as well as neurons in the mormyrid brain is substantially adapted to the high degree of differentiation of its electrosensory and telencephalic brain regions, but serotoninergic innervation is not involved in the circuitry of the most impressive part of the mormyrid brain; i.e., its large corpus and valvula cerebelli.

Differences in the fiber composition of the pyramidal tract in two- and 14-month-old rats

The present study is aimed at an electron-microscopic morphometrical analysis of the pyramidal tract of 14-month-old rats at the level of the pyramis medullae and the second cervical segment, and a comparison with data obtained for rats of two months of age. Between 2 and 14 months of age there is, at the level of the pyramis medullae of the left pyramidal tract, a statistically significant increase of the number of myelinated fibers, from 91,000 to 118,000, whereas the total number of unmyelinated fibers decreases from 133,000 to 101,000. On the right side at the same level there is no statistically significant change in the number of myelinated fibers, whereas there is a significant decrease of unmyelinated fibers at this side, from 148,000 to 89,000. At the second cervical level, a statistically significant increase in the number of myelinated fibers has been noted at both sides (from 43,000 to 60,000) between 2 and 14 months, whereas the mean total number of unmyelinated fibers at this level decreases somewhat (from 35,000 to 28,000), but is not statistically significant. Several processes which might be involved in the age-related changes observed are discussed, including the possibility of a shift from unmyelinated fibers to myelinated ones, withdrawal of corticobulbar fibers and ongoing outgrowth of myelinated corticofugal fibers after two months of age, and a summarizing scheme is presented. We conclude that the pyramidal tract of the rat changes in composition after the age of two months and that continuing outgrowth of myelinated corticospinal fibers is an important aspect of this continuing development.

Morphometric parameters of the superior colliculus of albino and pigmented rats

The superior colliculus (SC) or optic tectum of mammals consists of seven layers, numbered I-VII from superficial to deep, each of which has distinct connectivity patterns and electrophysiological response properties. The present study is devoted to a morphometrical analysis of neuronal diameters, densities, and numbers in different layers and regions of the SC of albino as well as pigmented rats in order to present a quantitative characterization of the collicular neuronal population involved in the different connectivities and functions of these compartments. The morphometric parameters were calculated from tracings of nuclei and cell bodies by means of Kontron-Videoplan equipment and a Micro PDP 11/23 computer. The mean soma diameter per superior colliculus appears to be 12.0 microns, the average neuronal density 70 cells per 0.001 mm3, and the total number of neurons about 600,000. The mean soma diameter gradually increases from superficial to deep layers (i.e., from 10.0 to 14.0 microns). Cellular density is highest in layer III, the retinal afferent layer (90 cells per 0.001 mm3), and decreases both in more superficial layers (to about 80 in layer I) and deeper layers (to about 44 in layer VII). About 25% of all collicular neurons are situated in layer II whereas layer I contains the lowest percentage of cells (4%). Rostrally within each collicular layer, cellular volumes are about 25% larger than caudally. On the other hand, neuronal densities are rostrally about 38% lower than caudally in all layers except for layers VI and VII. We conclude that collicular neurons, in contrast to collicular axons, are not arranged in distinct layers or clusters but basically establish a random network with only gradual transitions. In this respect, no statistically significant differences were observed between albino and pigmented rats.

The c-Fos protein interacts with c-Jun/AP-1 to stimulate transcription of AP-1 responsive genes

Cell lines stably transfected with metal inducible, MT-fos chimeric genes were used to study the ability of the c-fos gene product, Fos, to act as a transcriptional trans-activator. In 3T3MTfos cells, induction of Fos expression led to specific trans-activation of an AP-1 responsive reporter gene. Induction of Fos expression in F9MTfos cells, however, did not lead to trans-activation. Since, unlike NIH3T3 cells, F9 cells do not contain detectable levels of AP-1, we examined whether a c-Jun/AP-1 expression vector can restore the trans-activating effect of Fos in F9MTfos cells. Transfection with a functional c-Jun/AP-1 vector restored the specific trans-activating effect of Fos on AP-1 responsive constructs. When incubated with nondenatured cell extracts, anti-cFos antisera precipitated a protein complex composed of Fos and several Fos associated proteins (FAP). One of these, FAP p39, is structurally identical to c-Jun/AP-1. These results suggest that Fos is a trans-acting factor that is capable of stimulating gene expression not by direct binding to DNA but by interaction with the sequence-specific transcription factor AP-1. Therefore recognition of specific cis-elements by AP-1 is a prerequisite for Fos-mediated stimulation of gene expression.

Preparation and properties of monoclonal and polyclonal antibodies to mouse epidermal growth factor (EGF) receptors: evidence for cryptic EGF receptors in embryonal carcinoma cells

Monoclonal antibodies to mouse epidermal growth factor (EGF) receptor were prepared by the immunization of rats with receptor glycoprotein purified from mouse liver by affinity chromatography on immobilized EGF. Purified mouse EGF receptor retained EGF-inducible autophosphorylating activity and was antigenic in rats and rabbits. The monoclonal antibodies cross react very poorly with human EGF receptor, while polyclonal rabbit antibodies immunoprecipitate human, rat and mouse EGF receptor equally well. The rabbit antibody blocks EGF binding to mouse fibroblast cells and, at 20-fold higher concentrations, stimulates uptake of tritiated thymidine into DNA. This indicates that antibodies bind at or close to the EGF-binding site and can mimic the effects of the growth factor. None of the monoclonals bind at the EGF site of the receptor. Immunoprecipitation, immunoblotting, 125I-EGF cross linking, 125I-surface labelling, immunohistochemistry and autophosphorylation techniques were used to delineate the basis for the induction of EGF receptors when OC15 embryonal carcinoma (EC) cells differentiate into endodermal derivatives (END). EGF-stimulated autophosphorylation of a 170 X 10(3) Mr protein in solubilized OC15 EC cells is readily detectable, although intact EC cells do not bind or respond to EGF by all other tests. The results suggest that cryptic EGF receptors are present in EC stem cells, a finding with implications in development.

Afferent and efferent connections of cerebellar lobe C1 of the mormyrid fish Gnathonemus petersi: an HRP study

The corpus of the highly developed cerebellum of the weakly electric fish Gnathonemus petersi is differentiated into four lobes, numbered C1 to C4. The present paper deals with the extrinsic connections of the rostralmost lobe C1. Relevant nuclei were studied in normal histological material and HRP injections were placed in lobe C1, the neighbouring pedunculus valvulae, and the brainstem. The largest number of afferents to lobe C1 originates from the nucleus lateralis valvulae, a large nucleus of tightly packed small cells in the dorsal midbrain tegmentum. In Gnathonemus this nucleus encompasses nine subdivisions, of which the rostral, caudal, and exterolateral parts project in particular to lobe C1. Larger neurons in the dorsal midbrain tegmentum and presumed mesencephalic trigeminal neurons project to C1 as well. In the rhombencephalon, afferents to lobe C1 arise from the first funicular nucleus, the lateral reticular nucleus, and the inferior olive. Efferents of lobe C1 have been found to arise from a peculiar cell type in the Purkinje cell layer (so-called eurydendroid neurons) and to project predominantly to the nucleus of the fasciculus longitudinalis medialis, the nucleus reticularis superius and medius, and the trigeminal motor nucleus. Additional small projections terminate in the tectum mesencephali and in the nucleus reticularis inferior. Compared with other parts of the mormyrid cerebellum as well as with the cerebellum of other teleosts, the connections of lobe C1 appear to be quite restricted and specialized. In this respect the connections with the trigeminal nerve via the first funicular nucleus, the mesencephalic trigeminal nucleus, and the trigeminal motor nucleus are of particular interest. The absence of central cerebellar nuclei intercalated in the efferent cerebellar connections, in combination with the presence of a precerebellar nucleus (lateralis valvulae) involved in the afferent cerebellar connections, represents a remarkable difference between teleosts and other vertebrate classes.

Afferent and efferent connections of cerebellar lobe C3 of the mormyrid fish Gnathonemus petersi: an HRP study

The present paper is devoted to the extrinsic connections of lobe C3 of the highly differentiated corpus cerebelli of the electric fish Gnathonemus petersi. For this purpose, HRP injections or gels were placed in distinct parts of lobe C3 or its peduncle, in the pretectal region, and in the eye. Moreover, the presence of serotonin and tyrosine-hydroxylase was studied with immunohistochemical methods. The afferent connections of the rostral and caudal part of lobe C3 appear to differ considerably. Although both parts receive comparable projections from two pretectal nuclei (termed nucleus geniculatus and dorsal anterior pretectal nucleus) and the inferior olive, they receive projections from different parts of the nucleus lateralis valvulae, a large cell mass in the midbrain tegmentum, composed of small, tightly packed neurons. The caudal part of lobe C3 receives a projection from the most rostromedial cap of cells of this nucleus, whereas the rostral cap of lobe C3 receives efferents from the neighboring, more caudolateral, zone of cells of the nucleus lateralis valvulae. The caudal part of lobe C3, but not its rostral part, receives an additional projection from a nucleus in the isthmus region, termed nucleus Q. This nucleus sends a collateral projection to the torus longitudinalis. The efferents of both parts of lobe C3 project to slightly different parts of the midbrain tegmentum and the nucleus reticularis superior, and originate at least partly from eurydendroid cells. None of the nuclei and fiber tracts labeled could be shown to contain serotonin or catecholamines. The connections of lobe C3, as revealed by the present study, are compared with those of other parts of the mormyrid cerebellum and with those of the corpus cerebelli of other teleosts, with emphasis on the homology and functional significance of pretectocerebellar connections, the topical order in the cerebellar projections of the nucleus lateralis valvulae, and the relations between the cerebellum and torus longitudinalis. Comparison of the cerebellar connections in different teleostean species suggests that the strong development and the considerable differentiation of the cerebellum of mormyrids are related to at least two types of changes in the extrinsic connections, i.e.: a redistribution or parcelling of connections and the development of connections specific for mormyrids.

A detailed morphometrical analysis of the pyramidal tract of the rat

The present study is aimed at a quantitative analysis and comparison of the fibers of the pyramidal tract of the rat at two levels: the pyramis medullae and the second cervical segment. For this purpose both levels of the pyramidal tracts of 5 rats have been studied morphometrically at the ultrastructural level. Fiber numbers as well as fiber diameter distributions are presented for both myelinated and unmyelinated axons. At the level of the pyramis medullae the number of unmyelinated fibers (140,000 +/- 7000) exceeds the number of myelinated axons (103,000 +/- 6000). In contrast at the level of the second cervical segment the numbers of fibers of the axon populations studied are not significantly different, viz. 43,000 +/- 2000 myelinated and 35,000 +/- 8000 unmyelinated fibers. However, these numbers mean a significant decrease of myelinated axons (48%) compared with the pyramis medullae level and an even much larger decrease (75%) in the numbers of unmyelinated fibers. Diameter distributions, obtained from the minimal fiber diameter, show a similar, monomodal shape for all axon and myelin profiles. For unmyelinated axons the minimal diameter ranges from 0.05 to 1.21 micron with a mean of 0.18 +/- 0.03 micron. For myelinated axons a mean minimal diameter of 0.72 +/- 0.12 micron has been found (range 0.13-4.92 micron), whereas their diameter measured with myelin sheath measure 1.08 +/- 0.13 micron (range 0.25-6.03 micron). The average thickness of the myelin sheath is 0.2 micron and is strongly correlated to axon diameter. Furthermore, g-ratio has been computed at a mean of 0.65 and is fairly constant throughout the diameter spectrum. Several possibilities concerning the functional and anatomical qualities of the numerically important unmyelinated axon population in the pyramidal tract of the rat are discussed.

Product of the cellular oncogene, c-fos, observed in mouse and human tissues using an antibody to a synthetic peptide

The transforming gene of the osteosarcoma-producing FBJ murine sarcoma virus, v-fos, is homologous to a normal cellular gene, c-fos, in vertebrate species. Transcripts from the c-fos proto-oncogene accumulate to very high levels in late gestational mouse and human extra-embryonic tissues. We now report that these RNA transcripts are translated in these tissues. Rabbits were immunized with a synthetic peptide whose sequence is common to both c-fos and v-fos. After affinity purification on an immunosorbent containing the fos peptide (a nonapeptide), the antibody reacted with a component(s) in nuclei in sections of human and murine tissues and immunoprecipitated the v-fos gene product (p55) and a cellular protein of 39 kd (p39, complexed with fos) from lysates of metabolically-labelled virally transformed cells. Crude extracts of normal tissues contained major anti-fos-reactive proteins in the range of 55-60 kd as shown by protein blot analysis. Indirect immunofluorescence and immunoperoxidase staining showed that in addition to strong immunoreactive component(s) in the nuclei of extra-embryonic tissues of human and mouse, weaker reactions are detectable in all normal fetal and adult tissues tested. This demonstrates that fos-reactive protein is expressed in a wide variety of cells and tissues.

Dietary protein supplementation from vegetable sources in the management of chronic portal systemic encephalopathy

In a controlled cross-over trial, we have compared a conventional 40-g protein diet (30 g animal and 10 g vegetable, diet A) with an 80-g vegetable-protein-supplemented diet (30 g animal and 50 g vegetable, diet B) in the treatment of six patients with chronic stable portal systemic encephalopathy, requiring dietary and lactulose therapy. Each diet was given, in random order, for 5 days in hospital. EEG, clinical indices of encephalopathy, and the plasma amino acid profile were assessed at the end of each treatment period. The increase in vegetable protein intake was associated with minor improvement in EEG and clinical performance in two patients, and no change in the others. Fasting plasma phenylalanine and tyrosine were higher on diet B [phenylalanine 108.6 +/- 9.3 (SEM) mumol/L versus 99.6 +/- 8.37, p less than 0.05 (paired t test); tyrosine 153 +/- 15.2 mumol/L versus 140 +/- 14, p less than 0.05). The plasma branched-chain amino acid levels did not change, and the branched chain/aromatic amino acid ratio (BCAA/AAA) was lower on diet B (p less than 0.02). Fecal weights were not significantly altered. These results indicate that patients with chronic portal systemic encephalopathy are tolerant of protein supplementation from vegetable sources. A minor improvement in parameters of encephalopathy was seen in some individuals, despite a lowering of BCAA/AAA which some investigators have thought important in the pathogenesis of encephalopathy.

The ontogeny of epidermal growth factor receptors during mouse development

In an attempt to understand the role(s) of epidermal growth factor (EGF) in vivo during murine development, we have examined the 125I-EGF binding characteristics of EGF-receptors in membrane preparations of tissues from the 12th day of gestation to parturition. Using autoradiography, the earliest time that we could detect EGF-receptors was on trophoblast cells cultured for 3 days as blastocyst outgrowths. Trophoblast eventually forms a large portion of the placenta, where EGF-receptors have long been recognized. We measured the number and affinity of EGF-receptors on tissues dissected from conceptuses from the 12th day of gestation in order to identify a stage when tissues may be most sensitive to EGF. Whereas the number of EGF receptors increases during gestation for all tissues examined, the affinity of the receptors declines for carcass and placenta and remains relatively unchanged for brain and liver. This suggests that EGF may function differently throughout development. Our hypothesis is that EGF (or its embryonic equivalent) initially stimulates proliferation in embryonic cells and then stimulates differentiation as the tissues mature. In the adult, its main role could be to stimulate tissue repair after damage.

Functional anatomy of the tectum mesencephali of the goldfish. An explorative analysis of the functional implications of the laminar structural organization of the tectum

The present paper is aimed at an exploration of the possible functional significance of the laminar organization of the goldfish tectum at both the cellular and the synaptic level. For this purpose (1) the data concerning the structure of the teleostean tectum are surveyed, (2) a conceptual framework of the intratectal connectivity in the goldfish is proposed, (3) the electrophysiological data concerning the teleosteam tectum are surveyed and (4) the degree of correlation between the structural and physiological data available is discussed. Apart from the retina, tectal afferents originate from at least 10 other brain centers. At least 5 of these projections appear to be topographically organized. Tectal afferents, neurons as well as synapses reveal a characteristic intratectal lamination pattern. Tectal efferents project to at least 10 brain centers, and have until now been shown to arise from 6 cell types. The structural data surveyed allow the construction of a conceptual framework of tectal circuitry on the basis of 3 starting points. (1) The existence of at least 8 presynaptic zones or laminae, each containing a characteristic set of presynaptic structures (afferents and axons of interneurons). (2) The fact that the tectal postsynaptic structures (somata and dendrites of tectal neurons) each have a characteristic location, extension and synaptic density, which determines the relative importance of the different presynaptic zones for each cell type. (3) The laminar specificity hypothesis, which implies that presynaptic structures that coexist in a particular presynaptic zone terminate without preference on all types of postsynaptic structures within that zone. The conceptual framework of tectal circuitry is quantified in terms of connectivity index and connective importance. Analysis of the framework constructed leads to a detailed description of the intratectal pathways involved in the processing of the 4 main streams of tectal input (i.e. visual, toral, telencephalic and 'deep' input). It was concluded that the laminar organization of the tectum is primarily relevant for multimodal integration and that the tectal cell types each receive a characteristic sample out of the multimodal information available in the different tectal layers.(ABSTRACT TRUNCATED AT 400 WORDS)

A Golgi-electron microscopic study of goldfish optic tectum. II. Quantitative aspects of synaptic organization

The size, density, and number of the synaptic contacts of three types of interneurons (types I, III, and XIV of Meek and Schellart, '78) and three types of efferent neurons (types VI, XII, and XIII) of the goldfish optic tectum were quantified by means of a quantitative stereological study of Golgi-EM serial sections. Furthermore, an estimation was made of the percentage of optic terminals on these six cell types and of the ratio between terminals with pleomorphic and terminals with round vesicles. The mean density of contacts per receptive component (i.e. the cell body and the different parts of the dendritic tree) varies from 0 to 100 per 100/micrometer2 surface, corresponding to 0-8% receptive surface. Each cell type has a characteristic average density as well as a characteristic density distribution along the distinct components. This suggests that the receptive components of the tectal cell types investigated have a predetermined density and that a morphological classification of tectal cells has functional relevance. The mean length of the contact zones in the ultrathin sections varies from 213 to 332 nm for identified postsynaptic elements and from 188 to 293 nm for identified presynaptic elements. The size of the contacts on the distinct receptive components appears to be primarily related to the tectal lamination pattern. Distinct types of axons, however, have characteristic mean sizes of contacts. This might suggest that the size of the contacts, contrary to their density, is primarily determined by the presynaptic elements. The mean number of synaptic contacts calculated per cell type is as follows: type XIV, 200; type III, 450; type VI, 1,400; type I, 2,100; type XII, 4,200; and type XIII, 5,400. Multiplication of these numbers with the number of cells per tectal half shows that the population of type XIV cells has by far the most synaptic contacts, since their low number of synaptic contacts is clearly overruled by their high frequency of occurrence. Optic terminals, identified by their characteristic mitochondria and large round vesicles, appear to contribute to about 10-20% of the contacts on identified post-synaptic elements in layer 5. The ratio between presynaptic elements with pleomorphic vesicles and those with round vesicles shows a slight tendency to increase when the distance to the origin of the axon decreases. It is concluded that a combination of the Golgi-EM technique with quantitative stereological methods appears well suited to the study of the synaptic organization of brain centers, and that combination of quantitative Golgi-EM with neuronal tracing methods (degeneration, HRP, autoradiography) offers good prospects for detailed investigations of neuronal connectivity.

A Golgi-electron microscopic study of goldfish optic tectum. I. Description of afferents, cell types, and synapses

A study of goldfish optic tectum was performed with conventional electron microscopy and with the Golgi-EM technique described by Fairén et al. ('77). Five types of tectal afferents, three types of interneurons and three types of efferent neurons were investigated. Afferents from the torus longitudinalis, which terminate in the marginal layer, contain round synaptic vesicles with a mean diameter of 43 nm. Optic afferents, which terminate in the superficial gray and plexiform layer, are characterized by pale mitochondria with dilated cristae and round vesicles with a mean diameter of 49 nm. Afferents of unknown origin, terminating in several tectal layers, can be subdivided in three types; one containing round vesicles and two containing pleomorphic vesicles with different degrees of ellipticity. The three types of interneurons studied (type I, III and XIV, of Meek and Schellart, '78) were selected on basis of their high frequency of occurrence. The apical dendrites of type I neurons make many synaptic contacts with the marginal axons. All three types have dendrites in the superficial gray and plexiform layer making contacts with optic nerve terminals. In addition, their dendrites and cell bodies make synaptic contacts with several types of unidentified presynaptic elements. The axon terminals of type I and of type XIV contain round vesicles with a mean diameter of 45 and 46 nm respectively. Three of the four types of efferent neurons present in the goldfish tectum were studied (type VI, XII and XIII). Two of them make contact with optic terminals (type VI and XII) and two make contact with tectal afferents of unknown origin in the central white layer or in the lower part of the central gray layer (type XII and XIII). The axons of all three types become myelinated at some distance from their origin. Their initial unmyelinated parts are covered with a so-called "outer surface coating", have no collaterals and are occasionally (type VI and XII) or frequently (type XIII) postsynaptic to other elements. The archiform axons of type XIII and to a lesser extent also the sherpherds-crook shaped axons of type XII, have a close apposition to looping and narrowing dendrites in the inner plexiform layer. The present results concerning neuronal circuitry of the goldfish optic tectum are summarized in a tentative scheme.

The effect of kainic acid on the hippocampal content of putative transmitter amino acids

The time courses of the changes in the contents of GABA (gamma-aminobutyric acid), glutamate, aspartate, taurine, glycine and alanine were measured in both hippocampi of rats which were rejected in one hippocampus with kainic acid (KA). The contents of these amino acids were measured with high performance liquid chromatography. The hippocampal contents of GABA, glutamate, aspartate and taurine were reduced homolaterally to the KA injection; in contrast, the contents of glycine and alanine failed to change. The extent of the reductions of GABA, glutamate, aspartate and taurine was dependent on the size of the lesion caused by KA. The greatest decrease occurred after two simultaneous injections of KA, in dorsal and ventral hippocampus. An analysis of the amino acids at different levels of the hippocampus after dorsal injections of KA showed that in the hippocampus the amino acidergic axons do not travel longitudinally. This study suggests that GABA, glutamate, aspartate and taurine are preferentially located in intrinsic hippocampal neurons with short axons.

A Golgi study of goldfish optic tectum

A study of goldfish optic tectum was performed with rapid-Golgi, Golgi-Kopsch and a modified Golgi-Cox impregnation which proved quite suitable to impregnate cells in the middle tectal layers and to study more closely axonal properties. Fifteen cell types are distinguished, based upon the position of dendritic trees and axonal properties. Two cell types are found with dendrites in the marginal layer: type I with an axon terminating in the central gray layer and type II without an impregnated axon. Three cell types (III, IV and V) have dendrites in a single, specific tectal layer and an axon terminating within the tectum. Five cell types (VI-X) have dendrites in two horizontal planes. Two of them have myelinated axons leaving the tectum, whereas the axons of the remaining three types project to different tectal layers. While these first ten cell types have dendrites almost exclusively in the superficial half of the tectum, the remaining five types have dendrites in deeper layers too. This especially holds for the most conspicuous tectal cells (types XII and XIII), which have dendritic trees branching at three or more horizontal levels and a myelinated axon leaving the tectum, with sometimes a very peculiar course (XIII1). Also type XI has three or more dendritic trees, but its axon was not found. The numerous cells with cell bodies in the deepest tectal layer (type XIV) have dendrites and axonal terminations anywhere in the tectum, except in the most superficial and the deepest layer. However, most dendrites occur in the optic layers, whereas the axons, always originating from the dendritic shaft in the superficial tectal half, generally terminate in the middle tectal layers. Type XV cells have their soma in the deepest tectal layer as well, but their dendrites do not reach the optic layers. Per tectal lobe the following numbers are estimated: type I : 5,000-20,000 neurons; Type III : 2,500-10,000; types IV--XIII : each 500-2,000 and type XIV : 1,000,000-2,000,000. The total number of myelinated tectal efferents is estimated at 2,000-8,000. Comparison with other Golgi studies in teleosts leads to the conclusion that the tecta of these species of fish are basically similar.

Myelin impregnation: an improved Golgi-Cox modification

Optic tecta of goldfish were coated with egg yolk and immersed for only one week in one of the following impregnation fluids: a) Solution A + B; A = 1 g K2Cr2O7 and 1 g HgCl2 boiled for 15 min in 85 ml distilled water and allowed to cool; B = 0.8 g K2Cr2O4 and 0.5 g KWO4 dissolved in 20 ml distilled water. b) Solution A + B two volumes diluted with boiled distilled water. c) Solution A + B four volumes diluted with boiled distilled water. Each tectum was immersed 6 hr in 100 ml distilled water containing 0.5 g LiOH and 15 g KNO3, washed 18 hr in 500 ml 0.2% acetic acid, dehydrated with ethanol, and embedded in low viscosity nitro cellulose. Sections were cut at 100 micron with a rotary microtome after clearing with cedarwood oil. Methods b) and c) have two advantages compared with method a), the original Golgi-Cox method. First, more cells are impregnated, especially in the layers extending 200-400 micron below the surface, and dendrites as well as unmyelinated axons are well impregnated. Second, myelin sheaths are impregnated and can be recognized by their peculiar chain-like appearance. The described Golgi-Cox modification offers an appropriate method to study the morphology of superficially located nervous tissue.