Transplantation of brain tissue in the brain of adult rats

Summary Brain tissues obtained from rat embryos were transplanted in the forebrain and/or cerebellum of the adult rats. The transplants survived, grew and achieved normal cellular and cytoarchitectural differentiation. They had become anatomically integrated with the host brain. The animals did not show any obviously detectable abnormal behavior or pathology of the brain. The transplants survived as long as the animals did suggesting that they had become a part and parcel of the host brain.Supported by research grants NS-08817 and CA-14650 from N.I.H.     

A new technique of pinealectomy for adult rats

Summary A new technique of pinealectomy for rats is described which brings the pineal into view of the experimenter facilitating its removal and also allows for completely parallel sham operations.Acknowledgments. We thank Drs J. A. Mitchell, R. R. Gala and A. Weinsieder for their cooperation in the initial phases of this work and Hedwig A. Murphy for her help with the illustrations. Supported by USPHS, grant No. RR 05384, and the Department of Anatomy.     

Ultrastructural features of pituicytes in the neural lobe of adult rats

Riassunto Nella presente nota sono sinteticamente analizzati i caratteri ultrastrutturali dei pituiciti e, in particolare, i rapporti dei pituiciti stessi con le fibre neuro-secretorie spesso realizzantisi a livello dei prolungamenti pituicitari periferici, le zone di contatto interpituicitario ricche di complessi giunzionali e l'esistenza nel lobo neurale di cellule poco differenziate che potrebbero rappresentare i precursori dei pituiciti maturi.     

Freezing and transplantation of brain tissue in rats

Summary Neocortical tissue obtained from rat embryos was frozen and stored at –70°C for 6 h prior to transplantation into the cerebellum of neonatal rats. Growth, differentiation, and integration of this tissue within the host brain was comparable to that obtained from freshly dissected and transplanted tissue. It is suggested that freezing to low temperatures does not adversely effect the viability or transplantability of the neural tissue.Supported by N.I.H. research grants Nos NS-08817 and CA-14650.     

Ultrastructural features of pituicytes in the neural lobe of adult rats. The cytoplasm

Riassunto La nota di cui sopra analizza sistematicamente l'organizzazione submicroscopica del citoplasma pituicitico soffermandosi particolarmente sul possible significato delle inclusioni lipidiche, dei corpi densi e dei prolungamenti periferici del pituicita stesso.     

Ultrastructural features of pituicytes in the neural lobe of adult rats. The peripheral processes

Riassunto Sono state analizzate le caratteristiche ultrastrutturali dei prolungamenti citoplasmatici dei pituiciti i quali formano un reticolo cellulare atto ad aumentare la superficie di contatto tra i pituiciti e le fibre neurosecretorie.     

Stereotaxic localization of amygdaloid nuclei in rats from weaning to adulthood

Zusammenfassung Stereotaxische Koordinaten werden für die Setzung von Läsionen in den Amygdalen von Ratten (54–236 g Körpergewicht) ermittelt. Die Daten ermöglichen auch die Extrapolation von Strukturen, die in dieser Mitteilung nicht erwähnt wurden.

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This investigation was supported by U.S.P.H.S. Grant No. HE 06975 of the National Heart Institute.     

Effects of cysteine and N-acetyl cysteine on GSH content of brain of adult rats

Intraperitoneal injections of cysteine or N-acetyl cysteine induce a depletion of reduced glutathione (GSH) in rat brain. The doses required to promote GSH depletion are lower than those reported to cause a disseminate neurodegenerative syndrome. Since physiological GSH concentrations are required to maintain cell membranes, we suggest that consideration of the cysteine-induced GSH depletion is important in attempts to understand the mechanism of cysteine-induced cytotoxicity in brain.     

Delineating multiple functions of VEGF-A in the adult brain

Vascular endothelial growth factor-A (abbreviated throughout this review as VEGF) is mostly known for its angiogenic activity, for its activity as a vascular permeability factor, and for its vascular survival activity [1]. There is a growing body of evidence, however, that VEGF fulfills additional less ‘traditional’ functions in multiple organs, both during development, as well as homeostatic functions in fully developed organs. This review focuses on the multiple roles of VEGF in the adult brain and is less concerned with the roles played by VEGF during brain development, functions described elsewhere in this review series. Most functions of VEGF that are essential for proper brain development are, in fact, dispensable in the adult brain as was clearly demonstrated using a conditional brain-specific VEGF loss-of-function (LOF) approach. Thus, in contrast to VEGF LOF in the developing brain, a process which is detrimental for the growth and survival of blood vessels and leads to massive neuronal apoptosis [2–4], continued signaling by VEGF in the mature brain is no longer required for maintaining already established cerebral vasculature and its inhibition does not cause appreciable vessel regression, hypoxia or apoptosis [4–7]. Yet, VEGF continues to be expressed in the adult brain in a constitutive manner. Moreover, VEGF is expressed in the adult brain in a region-specific manner and in distinctive spatial patterns incompatible with an angiogenic role (see below), strongly suggesting angiogenesis-independent and possibly also perfusion-independent functions. Here we review current knowledge on some of these ‘non-traditional’, often unexpected homeostatic VEGF functions, including those unrelated to its effects on the brain vasculature. These effects could be mediated directly (on non-vascular cells expressing cognate VEGF receptors) or indirectly (via the endothelium). Experimental approaches aimed at distinguishing between these possibilities for each particular VEGF function will be described. This review is only concerned with homeostatic functions of VEGF in the normal, non-injured brain. The reader is referred elsewhere in this series for a review on VEGF actions in response to various forms of brain injury and/or brain pathology.     

Lysozyme levels in tissues of iron-deficient rats

Summary Rats were fed either diets sufficient (300 ppm) or insufficient (5 ppm) in iron for 10 weeks. The iron-deficient animals had lowered hemoglobin and hematocrit levels and higher levels of kidney lysozyme activity than did control animals. There were no significant changes in serum and spleen lysozyme activity levels.Supported in part by grant HL18712-02, Heart and Lung Institute, NIH.     

Lysozyme levels in tissues of iron-deficient rats

Fats were fed either diets sufficient (300 ppm) or insufficient (5 ppm) in iron for 10 weeks. The iron-deficient animals had lowered hemoglobin and hematocrit levels and higher levels of kidney lysozyme activity than did control animals. There were no significant changes in serum and spleen lysozyme activity levels.     

Mechanism of neurogenesis in adult avian brain

Summary Adult neurogenesis in birds offers unique opportunities to study basic questions addressing the birth, migration and differentiation of neurons. Neurons in adult canaries originate from discrete proliferative regions on the walls of the lateral ventricles. They migrate away from their site of birth, initially at high rates, along the processes of radial cells. The rates of dispersal diminish as the young neurons invade regions devoid of radial fibers, probably under the guidance of other cues. The discrete sites of birth in the ventricular zone generate neurons that end up differentiating throughout the telencephelon. New neurons may become interneurons or projection neurons; the latter connect two song control nuclei between neostriatum and archistriatum. Radial cells, that in mammals disappear as neurogenesis comes to an end, persist in the adult avian brain. The presence of radial cells may be key to adult neurogenesis. Not only do they serve as guides for initial dispersal, they also divide and may be the progenitors of new neurons.     

Mechanism of neurogenesis in adult avian brain

Adult neurogenesis in birds offers unique opportunities to study basic questions addressing the birth, migration and differentiation of neurons. Neurons in adult canaries originate from discrete proliferative regions on the walls of the lateral ventricles. They migrate away from their site of birth, initially at high rates, along the processes of radical cells. The rates of dispersal diminish as the young neurons invade regions devoid of radial fibers, probably under the guidance of other cues. The discrete sites of birth in the ventricular zone generate neurons that end up differentiating throughout the telencephalon. New neurons may become interneurons or projection neurons; the latter connect two song control nuclei between neostriatum and archistriatum. Radial cells, that in mammals disappear as neurogenesis comes to an end, persist in the adult avian brain. The presence of radial cells may be key to adult neurogenesis. Not only do they serve as guides for initial dispersal, they also divide and may be the progenitors of new neurons.     

Lactate dehydrogenase specificity and subunit assembly in neural tissues of the teleostPhallichthys amates

Summary The tissue specificity of lactate dehydrogenase (EC 1.1.1.27) in brain and eye of the teleostPhallichthys amates was examined by acrylamide gel electrophoresis. It is suggested that subunit association is a function of gene product accessibility superimposed upon genetic restriction of assembly.     

Degenerating pituicytes in the neural lobe of osmotically stressed rats

Riassunto Nella presente nota sono descritti gli aspetti degenerativi di pituiciti appartenenti al lobo neurale ipofisario di ratti sottoposti a disidratazione sperimetale.

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Acknowledgment. The technical help ofV. Panetta is greatly appreciated.     

Compensatory hypertrophy of the leydig cells in hemiorchidectomized adult rats

Summary Hemiorchidectomy in adult rats results in hypertrophy of the Leydig cells in the remaining testis. The other parts of the testis appear to be unaffected. Supported by the Swedish Medical Research Council (project 12X-05935) and the Harald Jeansson and Magn Bergvall Foundations.     

iPSC-derived neural precursor cells: potential for cell transplantation therapy in spinal cord injury

A number of studies have demonstrated that transplantation of neural precursor cells (NPCs) promotes functional recovery after spinal cord injury (SCI). However, the NPCs had been mostly harvested from embryonic stem cells or fetal tissue, raising the ethical concern. Yamanaka and his colleagues established induced pluripotent stem cells (iPSCs) which could be generated from somatic cells, and this innovative development has made rapid progression in the field of SCI regeneration. We and other groups succeeded in producing NPCs from iPSCs, and demonstrated beneficial effects after transplantation for animal models of SCI. In particular, efficacy of human iPSC–NPCs in non-human primate SCI models fostered momentum of clinical application for SCI patients. At the same time, however, artificial induction methods in iPSC technology created alternative issues including genetic and epigenetic abnormalities, and tumorigenicity after transplantation. To overcome these problems, it is critically important to select origins of somatic cells, use integration-free system during transfection of reprogramming factors, and thoroughly investigate the characteristics of iPSC–NPCs with respect to quality management. Moreover, since most of the previous studies have focused on subacute phase of SCI, establishment of effective NPC transplantation should be evaluated for chronic phase hereafter. Our group is currently preparing clinical-grade human iPSC–NPCs, and will move forward toward clinical study for subacute SCI patients soon in the near future.     

Monoamine oxidase activity in tissues of spontaneously hypertensive rats

Summary Monoamine oxidase (MAO) activity was assayed both in central and peripheral blood vessels of spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar Kyoto rats (WKR). The activity of MAO in the brain and peripheral vasculature was essentially the same in both SHR and WKR. It can therefore be concluded that central and peripheral vascular MAO activity is not altered in the genetically hypertensive animals.