bluuebunny/crossref_metadata_2025_split huggingface dataset:
Timecourse of effects of triiodothyronine on mouse cerebellar cells cultured by two different methods
Authors: Messer Anne , Snodgrass Gary L. , Maskin Paul 
Published: April 2003

AbstractDissociated cells from week‐old mouse cerebellum were grown on either polylysine coated coverslips or on uncoated coverslips. Polylysine coated coverslips give rise to cultures containing all of the cerebellar cell types except Purkinje cells. Use of uncoated coverslips gives rise to cultures which are depleted of granule cells because the granule cells are unable to adhere to glass without a substrate present. The uncoated coverslip cultures are therefore enriched in glial and other non‐neuronal cells. Effects of triiodothyronine on each type of culture were then examined as a function of time.On coated coverslips hormone treatment caused a noticeable increase in cell clumping at 1 week, and seemed responsible for a leveling off of the decline in total high‐affinity uptake of γ‐aminobutyric acid, as well as for a small increase in β‐alanine inhibited uptake between 2 and 3 weeks. There was no effect on the overall uptake of thymidine. On uncoated coverslips triiodothyronine treatment significantly increased the thymidine uptake at days 2 and 3, and increased the proportion of Bergmann‐like to velate astrocytes at 1 week. There were, however, no significant differences in GABA uptake at any of the time points examined.We conclude that in cerebellar cultures lacking Purkinje cells, triiodothyronine affects both the rate of acquisition and the timecourse of morphological changes (possibly reflecting transformation to more differentiated states) of glial cells but not of neurons. These results are consistent with the hypothesis that, in vivo, thyroxine acts indirectly via Purkinje cells to give developmental signals to neuroblasts and/ or neurons.
The phagocytes of neonate rat primary mixed glial cultures
Authors: DuBois J.H. , Hammond‐Tooke G.D. , Cuzner M.L. 
Published: April 2003

AbstractThe phagocytes present in mechanically dissociated neonate rat cerebral hemispheres have been cultured and characterized both qualitatively and quantitatively. They comprise about 10% of the starting cell suspension and persist but do not proliferate in culture. They do not possess neuronal or neuroglial antigens but do express the leukocyte common antigen and readily ingest both latex beads and opsonized erythrocytes. the latter by an Fc receptor‐mediated process. Evidence is presented that these cells are a bona fida component of the neonate central nervous system.
Ephemeral existence of a single catecholamine synthetic enzyme in the olfactory placode and the spinal cord of the embryonic rat
Authors: Foster George A. , Schultzberg Marianne , Dahl Doris , Goldstein Menek , Verhofstad Albert A.J. 
Published: April 2003

AbstractThe distribution of three catecholamine synthetic enzymes (tyrosine hydroxylase, l‐aromatic acid decarboxylase and dopamine β‐hydroxylase), of the catecholamines themselves (dopamine and noradrenaline) and of a marker for neuronal intermediate filaments (neurofilament) was investigated in the embryonic rat using immunohistochemical and histofluorescence methods.At early stages of gestation (days 11–13), large numbers of tyrosine hydroxylase immunoreactive cells and fibres were apparent in the ventro‐lateral spinal cord, and in and around the olfactory placode. In both cases, tyrosine hydroxylase positive fibres coursed between the proliferative layer and the surrounding mesenchyme, indicating the considerable degree of morphological differentiation. The similar disposition of neurofilament‐like immunoreactivity in the same regions suggested that the tyrosine hydroxylase containing structures were neuronal.Within 2–3 days of their first manifestation, the tyrosine hydroxylase immunoreactive neurons disappeared. In the spinal cord, this coincided with their migration out of the mantle layer. Over this same period, neither of the other enzymes involved in the synthesis of noradrenaline, namely l‐aromatic acid decarboxylase and dopamine β‐hydroxylase, nor dopamine and noradrenaline themselves, could be detected.It is concluded that some neurons in the olfactory placodal region and the ventrolateral spinal cord temporarily express a single specifically catecholaminergic enzyme, tyrosine hydroxylase, which is not utilized at that time in catecholamine synthesis. It is suggested that the control of transcription of the gene coding for tyrosine hydroxylase is independent of that for other catecholaminergic synthetic enzymes.
Cell proliferation in the embryonic mouse neocortex following acute maternal alcohol intoxication
Authors: Kennedy L.A. , Elliott M.J. 
Published: April 2003

AbstractExperiments were conducted to examine the effects of ‘binge’ or acute maternal alcohol intoxication during the early proliferative phase of embryonic brain development. Primiparous mice received ethanol as 0, 10, 15 or 20% (v/v) aqueous solutions by gavage on days 13, 14 and 15 of gestation. Mean daily doses were 0.0, 2.58, 4.03 and 5.40 ml/kg, respectively. There was no alcohol‐related reduction in fetal body weight, length or fixed brain weight. Coronal sections (1 μm) of the dorsal roof of the lateral ventricles over the optic chiasma were examined from nine embryonic day 15 brains for each treatment group. The ventricular surface index of mitotic figures, the number and distribution of non‐surface mitotic figures, and the depth of the cortical roof and its constituent layers were determined. There was no alcohol‐related difference in any of these parameters. These results are in contrast to those of a previous experiment using the same mouse strain, in which prolonged or chronic maternal alcohol consumption in the drinking water from days 11 to 19 of pregnancy was associated with a reduction in the surface index, a reduction in the depth of the cortical roof and an increase in the non‐surface mitotic figures. These latter changes, however, occurred in the presence of reduced body weight. Our observations suggest that during this particular developmental period (corresponding to the second trimester of human pregnancy) alcohol‐related reductions in brain growth parallel restrictions in general body growth.
A possible relationship between concentration of microperoxisomes and myelination
Authors: Adamo Ana M. , Aloise Pedro A. , Pasouini J. M. 
Published: April 2003

AbstractUsing catalase activity as a marker enzyme of microperoxisomes we determined the presence of these organelles in rat cerebral cortex (grey matter) and in brain stem (white matter) throughout development.While in grey matter the values of specific activity of catalase remained constant during all the period studied, in white matter the values increased up to 17 days of age, remained constant up to 31 days and decreased thereafter. Studies carried out in isolated oligodendroglial cells confirmed the results obtained in white matter. The results give support to the hypothesis of a possible relationship between the increase in the population of microperoxisomes and the appearance of myelin.
Cognin distribution during differentiation of embryonic chick retinal cells in vitro
Authors: Hausman R. E. , Katz M. S. , Dobi E. T. , Offermann J. 
Published: April 2003

AbstractDifferentiation of individual retina neurons is closely linked to development of retina function. This differentiation may be intrinsic to the cell or determined by the position of the cell within the developing tissue. Retina cognin, a cell‐cell recognition protein, which may itself mediate positiondependent cell interactions in vivo exhibits a characteristic change in distribution during embryonic chick development. Cognin is progressively lost from the outer retina in a manner which appears position‐dependent. 10 We asked if this change in cognin distribution was actually position‐dependent or intrinsic to the retina cells. Neural retina cells from 8‐day‐old chick embryos were cultured in vitro. Continued differentiation of the cultured cells was demonstrated by neurite outgrowth and characteristic increases in choline acetyltransferase and glutamic acid decarboxylase activity. In such cultures, the characteristic developmentally related disappearance of retina cognin occurred as in vivo. This indicated that this aspect of retina neuronal differentiation was independent of position within the tissue and likely intrinsic to individual cells after 8 days of embryonic development.
Maintenance of neuritic arborization in mitotic neuroblasts identified by neurofilament immunoreactivity
Authors: Asou Hiroaki , Iwasaki‐Mutou Noriko , Hirano Shuske , Dahl Doris 
Published: April 2003

AbstractThe morphology of mitotic cells identified as neuronal precursors by neurofilament immunoreactivity was studied by scanning electron microscopy in primary dissociated cultures of fetal rat cerebral hemispheres. It is shown that neurofilament‐positive neuroblasts maintain their neuritic arborization during cell division suggesting a cytoskeletal function for the neurofilament.
Ependymal lining of infundibular recess in perinatal rats: Relationships with portal capillaries and permeability
Authors: Ugrumov M.V. , Mitskevich M.S. , Halász B. , Kiss J. , Borisova N.A. 
Published: April 2003

AbstractStructure and permeability of the ependymal lining the infundibular recess were studied in perinatal rats with silver impregnation, electron microscopy, radioautography and tracer techniques. According to our data basal processes of ependymal cells reach the primary portal plexus linking the 3rd ventricle and the hypophysial portal system all through the perinatal period. After birth, some of the processes penetrate into the perivascular space of the primary portal plexus and abut there on the endothelium of capillaries. Ependymal cells of fetuses and neonates are joined by specialized junctions (tight junctions, gap junctions and zonulae adhaerentes). Intraventricularly injected ionic lanthanum crosses the ependymal lining of fetuses both trans‐ and extra‐cellularly everywhere in the infundibular recess. By postnatal day 9 only the rostral portion of the recess remains readily permeable. Caudally, extracellular leakage becomes highly restricted, apparently due to the appearance of circumferential tight junctions. Finally, [3H]dopamine seems to penetrate through the ependymal lining in the same way as ionic lanthanum entering the portal capillaries.These findings suggest that the adenohypophysiotropic neurohormones can penetrate from the cerebrospinal fluid into the portal circulation from the very beginning of the establishment of the hypothalamo‐hypophysial functional relationships during ontogenesis.
Paradoxical sleep deprivation of the mother enhances DNA synthesis in fetal rat brain: Autoradiographic and biochemical evidence
Authors: Zucconi Giglola Grassi , Belia Silvia , Menichini Enrico , Castigli Emilia , Giuditta Antonio 
Published: April 2003

AbstractPregnant rats were deprived of paradoxical sleep for 3 days starting on the 18th gestational day. The condition of PS‐D was imposed by confinement on a small platform surrounded by water or by daily injections of clomipramine. Four hours before the killing rats received a s.c. injection of [3H]‐thymidine. The amount of radioactive DNA determined by autoradiography in several regions of fetal brain was found to be markedly increased under both experimental conditions in comparison with the control fetal brain. Considerably more limited effects were observed in kidney. Comparable changes of lower magnitude were obtained by comparing the specific radioactivity of DNA samples purified by chlorophorm extraction and digestion with RNase and proteinase K. The results fully confirm our previous data obtained under similar experimental conditions but based on the analysis of an acid‐washed DNA fraction.
Developmental changes in hypothalamic melatonin levels of male rats
Authors: Catala M. D. , Quay W. B. , Timiras P. S. 
Published: April 2003

AbstractHypothalamic melatonin levels of Long‐Evans male rats were studied at three ages (25, 55–60 and 90 days), at four times of the day in the autumn (6:00, 12:00, 18:00 and 24:00), and at two times (12:00 and 24:00) in the spring using radiommunoassay. Melatonin levels increased markedly at noon at 55–60 days of age, compared with the levels at the same time of the day at 25 and 90 days. This increase persisted in autumn and spring. The 24‐hr pattern in hypothalamic melatonin was the inverse of that in the pineal, with the levels at noon higher than those at midnight. This pattern was detectable at 25 days of age although the difference in melatonin between 12:00 and 24:00 hr was not great. The day/ night difference was prominent by 55–60 days of age and disappeared by adulthood (90 days). This 24‐hr pattern was similar in spring and autumn in the three ages studied. Although in the 55–60‐day‐old group the melatonin ratio (noon/midnight) was the same in autumn and spring, the absolute levels of melatonin in spring were significantly lower. The findings are consistent with the general concept of a modulatory role of melatonin in control of hypothalamo‐hypophyseal GnRH and gonadotropin function and the timing of the developmental maturation of this neuroendocrine axis. Demonstration of the mechanism of melatonin's action at the hypothalamic level will be facilitated by further definition of quantitative developmental changes.
Early changes of surface morphology in monolayer cultures of neural retina cells. The effect of p‐bromophenacyl bromide
Authors: Suburo Angela M. , de Job Claudia Cei 
Published: April 2003

AbstractScanning electron microscopy was used to study the surface morphology of neural retina cells from fetal rats. Dissociated cells were plated on polyornithine and examined after 1.5–3.0 hr in vitro. A quantitative analysis of the proportion of cells with and without processes was made and the former were classified according to the length and number of their processes.Treatment with p‐bromophenacyl bromide (BPB), a selective inhibitor of phospholipase A2 (PLA2), induced significant changes on the early surface activity of retinal cells. An inhibitory effect on cell process formation was observed in monolayers grown for 2 hr in the presence of BPB: process formation was also inhibited when high concentrations (10−6 M or more) were applied as a 30 min pulse, whereas a similar pulse of a lower concentration (10−7 M) stimulated the appearance of cells with short processes. These observations suggest that PLA2 or some other BPB‐reactive substance is involved in the extension of neural cell processes.
Temporal development of gaba agonist induced alterations in ultrastructure and gaba receptor expression in cultured cerebellar granule cells
Authors: Hansen Gert H. , Belhage Bo , Schousboe Arne , Meier Eddi 
Published: April 2003

AbstractThe temporal development of the effect of THIP (4,5,6,7‐tetrahydroisoxazolo[5,4‐c]pyridin‐3‐ol) on the ultrastructure composition and GABA receptor expression in cerebellar granule cells was investigated by quantitative electron microscopy (morphometric analysis) and GABA binding assays. It was found that the cytoplasmic density of smooth endoplasmic reticulum was decreased, while the cytoplasmic density of rough endoplasmic reticulum, Golgi apparatus, vesicles and coated vesicles was greatly enhanced after exposure of the cells to THIP (150 μM) for only 1 hr. In cerebellar granule cells exposed to THIP (150 μM) for 3 hr low affinity GABA receptors were induced. These findings show that the effect of THIP on the ultrastructure composition and GABA receptor expression in cultured cerebellar granule cells may be interrelated and moreover it is likely that the turn‐over of GABA receptors is extremely fast.
Ultrastructural analysis of primary cilium in the embryonic nervous tissue of mouse
Authors: Cohen E. , Meininger V. 
Published: April 2003

AbstractIn the embryonic nervous system, the morphology and spatial organization of the ciliary apparatus in the primordial cells, the neuroepithelial bipolar cells, has been analysed from frontal and horizontal ultrathin sections. Projecting into the ventricular fluid, the primary cilium is located just at the interface between the ventricular fluid and the cytoplasm of these cells. Always associated with a basal body and a centriole, their structural components are nine microtubule doublets equally spaced around the luminal cylinder without central doublet. The cilium is short with a thick base displaying a reduced ciliary necklace and a 9 + 0 pattern. In its tip, the pattern decreases from 7 + 0 to 2 + 0. The basal body differs from the basal body of the motil cilium by internal and external sheets interconnecting triplets from base to apex, the constant existence of an accessory basal foot and the scarcity of a ciliary rootlet. All these characteristics suggest that in the neuroepithelial bipolar cells the ciliary apparatus is a rigid, polarized and transient structure probably important in the possible exchange between the ventricular fluid and the developing nervous system.
Regional protein patterns of the embryonic chick brain: Developmental shifts and the effects of light stimulation
Authors: Zhang J. , Huether G. , Neuhoff V. 
Published: April 2003

AbstractThe developmental changes in the regional protein patterns of the embryonic brain of chick were analysed by micro‐two‐dimensional polyacrylamide gel electrophoresis stained by a highly sensitive procedure with Coomassie Brilliant Blue G‐250 that completely avoids background staining. More than 400 protein spots were resolved in a computerized plot. Many proteins of the various embryonic brain regions varied with age. At least six of these proteins changed remarkably during development. One of them (Mr 14K) was prominent at 6 days and disappeared after 12 days of incubation. One acidic protein (Mr 30K) appeared at 12 days together with two acidic protein spots near tubulin and increased with development. A group of more basic proteins (Mr 94K) was prominent at 6 day incubation and decreased during development. One more basic protein (Mr 20K) was first observed at 18 days of incubation in the metencephalon. It was identified as myelin basic protein, and strikingly increased in all brain regions until hatching. A group of basic proteins with high molecular weight (Mr 94K) appeared at day 12 of incubation, and increased remarkably before hatching. They were identified to be collagen associated with brain capillary vessels. Stimulation by intermittent light in ova from day 10 to day 16 caused a retarded appearance of these collagen proteins, and an increased formation of tubulin in the optic lobe of the developing chick embryo.
Prenatal development of the hippocampus in two strains of inbred mice
Authors: Luzzatto Annarosa Ciofi , Mangano Giorgina , Vonesch Nicoletta 
Published: April 2003

AbstractIn this paper we present some morphological observations on the morphogenesis of the hippocampus in two inbred strains of mice, C57BL/6J (C57) and DBA/2J (DBA), from day 16 (E16) to day 17 (E17) of prenatal life. At E16 some differences in the histoarchitecture of the hippocampal anlage begin to be detectable. At E17 the differences become more relevant, particularly those concerning the lamination pattern. The more relevant differences concern the differentiation of the pyramidal layer, which appears well defined in C57 mice, while in DBA mice there is no clearcut delimitation between the pyramidal layer and the intermediate zone, where numerous migrating neurons are present. These observations may be interpreted in terms of different migration rates for the neurons in the two strains.
Experimental modifications of postnatal differentiation and fate of glial cells related to axo‐glial relationships
Authors: Valat J. , Privat A. , Fulcrand J. 
Published: April 2003

AbstractThe fate of glial cell lines following Wallerian degeneration in the rat optic nerve was analysed after pulse labelling with [3H]thymidine. The rats were unilaterally enucleated at the key stages 2,5,8 and 20 days after birth. Three hours later, they were injected intraperitoneally with [3H]thymidine and killed after 1, 3, 5, 10 and 20 days survival. Oligodendrocytes were the most affected, being unable to differentiate after 2 days enucleation, dying rapidly or transforming into another cell type after 5, 8 and 20 days enucleation. The apparent stability of the astrocyte population is due to an equilibrium between increased differentiation from glioblasts and increased death, the latter being preponderant at the key stage 2 days. Finally, the steady increase in the number of microglia may be due to the transformation from other cells, either glioblasts for the early time intervals or oligodendrocytes later on. It appears, then, that the interrelation between glial cell lines during differentiation is more intricate than previously suspected and is closely dependent, for each line, upon the integrity of axons.
Effects of thyroid hormone on light/dark melatonin synthesis and release by young and maturing rat pineal glands in vitro
Authors: Catala M. D. , Quay W. B. , Timiras P. S. 
Published: April 2003

AbstractSynthesis and release of melatonin were studied in pineal expiants from 14‐ (young) and 60‐day‐old (‘maturing’) male Long‐Evans rats with or without added thyroid hormone, triiodothyronine (T3), at or near physiological levels and under light and dark conditions. Incubation for 6 hr (1200–1800) was in a synthetic medium; melatonin was measured by radioimmunoassay (RIA). In light, T3 increased melatonin levels in pineal and medium of cultures from either young or maturing animals. In dark, T3 decreased melatonin levels in the pineals of either age, but was without significant effect on levels in the medium. Since it is known from other work that 14‐day‐old rat pineal glands do not yet have a complete sympathetic innervation system, it is here doubly evident that T3 can modulate directly pineal synthesis and release of melatonin, and may not depend upon a mature sympathetic innervation. Light in the studied conditions was permissive from the stimulatory action of T3 on pineal synthesis and release of melatonin in vitro.
Stimulation of neurite outgrowth in vitro by a glycero‐ganglioside
Authors: Cannella Michael S. , Acher Aureliu J. , Ledeen Robert W. 
Published: April 2003

AbstractA glycerol‐containing analog of ganglioside, with sialic acid attached to a diglyceride‐like structure possessing two ether‐linked alkyl chains, was prepared synthetically and applied exogenously to three culture systems; neuro‐2A neuroblastoma cells, PC12 cells and dorsal root ganglia. This resulted in pronounced stimulation of neunte outgrowth in all three, demonstrating that sialo‐lipids(s) lacking ceramide and possessing sialic acid as the sole carbohydrate are able to promote neuritogenesis in approximately the same manner as naturally occurring gangliosides.