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.     

Role of grafted Schwann cells in the regeneration of intraspinal nerve fibers when peripheral nerve, skeletal muscle or submandibular gland fragments are transplanted into the spinal cord of the mouse

Small pieces of peripheral nerve, skeletal muscle or submandibular gland, taken from young or new-born mice, were grafted into the non-transected spinal cord of young albino mice, at the thoracic level, through a punctiform meningeal opening. Neighbouring intraspinal nerve fibres, severed during the grafting process, regenerate into and eventually throughout the transplants. In this regenerative process, sedentary or migrating Schwann cells of the transplants probably have a prominent influence in guiding the growth of the axonal sprouts they ensheathe and eventually myelinate.     

Neocortical transplants in the rat brain: an ultrastructural study

Electron microscopic analysis of neocortical transplants in the cerebellum of the host animals showed that the nerve cells, glial cells, and neuropil of the transplants were normal. These transplants showed anatomical integration with the host brain through various regions of interface. Neuropil interfaces were found to have a high density of synaptic profiles, and medullary interfaces had a very small number of synaptic profiles.     

Human embryonic stem cell-derived neurons establish region-specific, long-range projections in the adult brain

While the availability of pluripotent stem cells has opened new prospects for generating neural donor cells for nervous system repair, their capability to integrate with adult brain tissue in a structurally relevant way is still largely unresolved. We addressed the potential of human embryonic stem cell-derived long-term self-renewing neuroepithelial stem cells (lt-NES cells) to establish axonal projections after transplantation into the adult rodent brain. Transgenic and species-specific markers were used to trace the innervation pattern established by transplants in the hippocampus and motor cortex. In vitro, lt-NES cells formed a complex axonal network within several weeks after the initiation of differentiation and expressed a composition of surface receptors known to be instrumental in axonal growth and pathfinding. In vivo, these donor cells adopted projection patterns closely mimicking endogenous projections in two different regions of the adult rodent brain. Hippocampal grafts placed in the dentate gyrus projected to both the ipsilateral and contralateral pyramidal cell layers, while axons of donor neurons placed in the motor cortex extended via the external and internal capsule into the cervical spinal cord and via the corpus callosum into the contralateral cortex. Interestingly, acquisition of these region-specific projection profiles was not correlated with the adoption of a regional phenotype. Upon reaching their destination, human axons established ultrastructural correlates of synaptic connections with host neurons. Together, these data indicate that neurons derived from human pluripotent stem cells are endowed with a remarkable potential to establish orthotopic long-range projections in the adult mammalian brain.     

Transplantations interspécifiques de gonades embryonnaires de Phasianidés

Summary When indifferent gonads from red-legged partridges, Japanese quail or pintado embryos were transplanted into the coelomic cavity of early chick embryos, they differentiated into ovaries and testes, regardless of the sex of the host. Testicular transplants brought about the retrogression of both Müllerian ducts in female hosts, and ovarian transplants the feminization of the left testis in male hosts. This demonstrates hormonal activity of the embryonic gonads in the 3 species under study. Since the embryonic sex hormones show inter-specific activity, they may be of identical chemical nature.

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Avec la collaboration technique deA. Zeis.     

Stem cells from human apical papilla decrease neuro-inflammation and stimulate oligodendrocyte progenitor differentiation via activin-A secretion

Secondary damage following spinal cord injury leads to non-reversible lesions and hampering of the reparative process. The local production of pro-inflammatory cytokines such as TNF-α can exacerbate these events. Oligodendrocyte death also occurs, followed by progressive demyelination leading to significant tissue degeneration. Dental stem cells from human apical papilla (SCAP) can be easily obtained at the removal of an adult immature tooth. This offers a minimally invasive approach to re-use this tissue as a source of stem cells, as compared to biopsying neural tissue from a patient with a spinal cord injury. We assessed the potential of SCAP to exert neuroprotective effects by investigating two possible modes of action: modulation of neuro-inflammation and oligodendrocyte progenitor cell (OPC) differentiation. SCAP were co-cultured with LPS-activated microglia, LPS-activated rat spinal cord organotypic sections (SCOS), and LPS-activated co-cultures of SCOS and spinal cord adult OPC. We showed for the first time that SCAP can induce a reduction of TNF-α expression and secretion in inflamed spinal cord tissues and can stimulate OPC differentiation via activin-A secretion. This work underlines the potential therapeutic benefits of SCAP for spinal cord injury repair.     

Viscero-somatic reflexes following distension of urinary bladder in cats: role of supraspinal neuraxis

Viscero-somatic reflexes have been studied by recording monosynaptic reflexes following distension of the urinary bladder in intact, decerebrate and spinal animals. It was observed that the viscero-somatic responses following bladder distension are inhibitory in nature and this inhibition was highest in decerebrates and least in spinal animals. The site of viscero-somatic interaction probably lies in the bulbar area (supraspinal) and spinal cord.     

Neocortical transplants in the rat brain: an ultrastructural study

Summary Electron microscopic analysis of neocortical transplants in the cerebellum of the host animals showed that the nerve cells, glial cells, and neuropil of the transplants were normal. These transplants showed anatomical integration with the host brain through various regions of interface. Neuropil interfaces were found to have a high density of synaptic profiles, and medullary interfaces had a very small number of synaptic profiles.Acknowledgment. Research supported by Contract No. N00014-83 from the Office of Naval Research, Department of the Navy to E.N.A., and N.I.H. Research Grant No. NS-08817 to G.D. Das.     

Effects of the spinal cord section and of subsequent denervation on the mechanical properties of fast and slow muscles.

The Soleus muscle of the rat, 3--6 months old, becomes significantly faster than in the controls, if the spinal cord is cut at birth. Mechanical properties of Extensor Digitorum Longus (EDL) muscle are not altered by spinal cord section. In cordotomized animals Soleus muscle always remains slower than EDL muscle. Denervation, performed 3--6 months after birth, has the same slowing effects in the Soleus and EDL muscles, both in cordotomized and in the control animals.     

Viscero-somatic reflexes following distension of urinary bladder in cats: Role of supraspinal neuraxis

Summary Viscero-somatic reflexes have been studied by recording monosynaptic reflexes following distension of the urinary bladder in intact, decerebrate and spinal animals. It was observed that the viscero-somatic responses following bladder distension are inhibitory in nature and this inhibition was highest in decerebrates and least in spinal animals. The site of viscero-somatic interaction probably lies in the bulbar area (supraspinal) and spinal cord.Acknowledgment. The work was carried out with the financial assistance of the Indian Council of Medical Research, Govt of India. We are thankful to A. T. Pradhan, Abott Laboratories (India) Pvt. Ltd. for a generous supply of Nembutal.     

Effects of the spinal cord section and of subsequent denervation on the mechanical properties of fast and slow muscles

Summary The Soleus muscle of the rat, 3–6 months old, becomes significantly faster than in the controls, if the spinal cord is cut at birth. Mechanical properties of Extensor Digitorum Longus (EDL) muscle are not altered by spinal cord section. In cordotomized animals Soleus muscle always remains slower than EDL muscle. Denervation, performed 3–6 months after birth, has the same slowing effects in the Soleus and EDL muscles, both in cordotomized and in the control animals.     

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.     

Beobachtungen beim Transplantieren von Organanlagen am Embryo vonLoligo vulgaris (Cephalopoda,Decapoda)

Summary The author describes a method for transplanting the organ anlagen ofLoligo vulgaris embryos. The anlagen of the eye, the statocyste and the tentacle arm were explanted and transplanted in toto as homo- or heterografts on the vitelline syncytium in different regions of the embryo body. The transplanted anlagen combine perfectly with the host tissue and differentiate according to their original determination.     

Tetanus intoxication causes an increment of serotonin in the central nervous system

Summary Mice injected with tetanus toxin (TTx) showed an increase of 5-hydroxytryptamine (serotonin, 5-HT) levels in the central nervous system. The increment was not uniform thoughout the central nervous system. Particularly significant were the 25% and 80% increases observed, respectively, in whole brain and spinal cord. The levels of dopamine and norepinephrine remained unchanged. The subsequent studies of 5-HT turnover revealed a synthesis rate in the tetanic animals that was almost double that of controls. The degradation rate of the amine as well as the levels of 5-hydroxyindolacetic acid were unaffected.     

Tetanus intoxication causes an increment of serotonin in the central nervous system

Mice injected with tetanus toxin (TTx) showed an increase of 5-hydroxytryptamine (serotonin, 5-HT) levels in the central nervous system. The increment was not uniform throughout the central nervous system. Particularly significant were the 25% and 80% increases observed, respectively, in whole brain and spinal cord. The levels of dopamine and norepinephrine remained unchanged. The subsequent studies of 5-HT turnover revealed a synthesis rate in the tetanic animals that was almost double that of controls. The degradation rate of the amine as well as the levels of 5-hydroxyindolacetic acid were unaffected.     

Axoplasmic transport in regenerating limbs of Ambystoma maculatum larvae.

Axoplasmic transport of 3H-leucine labelled molecules from spinal cord segments into regenerating larval salamander limbs was observed. However, labelled molecules were not observed in cells of the regeneration blastema.     

Insights into autotransplantation: the unexpected discovery of specific induction systems in bone marrow stromal cells

Many kinds of cells, including embryonic stem cells and tissue stem cells, have been considered candidates for transplantation therapy for neuro- and muscle-degenerative diseases. Bone marrow stromal cells (MSCs) also have great potential as therapeutic agents since they are easily isolated and can be expanded from patients without serious ethical or technical problems. Recently, new methods for the highly efficient and specific induction of functional neurons and skeletal muscle cells have been developed for MSCs. These induced cells were transplanted into animal models of stroke, Parkinson’s disease and muscle degeneration, resulting in the successful integration of transplanted cells and improvement in the behavior of the transplanted animals. Here I describe the discovery of these induction systems and focus on the potential use of MSC-derived cells for ‘auto-cell transplantation therapy’ in neuro- and muscle-degenerative diseases. Received 27 April 2006; received after revision 5 June 2006; accepted 22 August 2006     

Paralysies révélatrices de la leucémie de Gross chez le rat

Summary Inoculation of Wistar CF rats with Gross virus induces in 86% of the animals a leukaemia which is associated, in nearly 50% of the cases, with a paralysis of the hind legs.This paralysis is due to the compression of the spinal cord by leukaemic cell infiltrates which develop in the lumbar area. No neurotropic virus has been found in these animals.     

Inductions cérébrales et médullaires chez les Oiseaux

Summary Two grafts of the Hensen's node, one young (stage 3) and the other older (stage 5+), were implanted into area opaca of the same blastoderm. The hosts were at stages 2, 3 and 4. The young grafts always elicited the formation of the brain. On the contrary, old grafts only induce very small spinal cords. Moreover, the frequency of spinal cord induction is lowest in the oldest hosts.     

成年大鼠脊髓损伤后内源性神经前体细胞的增殖与分化规律的研究

目的观察成年大鼠脊髓损伤后内源性神经前体细胞的增殖与分化,探讨内源性神经前体细胞的自然变化规律。方法制作脊髓压迫损伤模型,Brdu腹腔注射标记神经前体细胞,免疫荧光法(Immunofluoreseence)检测大鼠脊髓Brdu、GFAP、MBP阳性细胞数的变化。结果 1)正常组可观察到少量Brdu阳性细胞,脊髓损伤后Brdu阳性细胞显著增加(p0.05),并在第7天达到最大值,21天时仍高水平表达。2)正常组可见少量Brdu/GFAP和Brdu/MBP阳性细胞,脊髓损伤后Brdu/GFAP,Brdu/MBP双标阳性细胞数显著增加(p0.05)。结论脊髓损伤后神经前体细胞的数量在第7天达到最大值,我们认为,一周内可能是神经前体细胞增殖分化调控的关键时期。此外,新生星形胶质细胞和少突胶质细胞大量增殖,并与神经前体细胞的迁移、后肢功能恢复表现出一定的同步性,提示新生胶质细胞可能参与了脊髓损伤后神经功能的修复作用。