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Biomedical subjects

A Hormigo

Publications and source records attributed to A Hormigo.

11 recordsLinked to original sources

Radial glial cell line C6-R integrates preferentially in adult white matter and facilitates migration of coimplanted neurons in vivo.

C6-R is a cell line derived from C6 glioma cells that exhibits key properties of radial glia including the ability to support neuronal migration in culture. To explore its potential use in promoting neuronal migration in vivo, we analyzed the behavior of C6-R cells in the intact and injured adult rat CNS. At 6-11 days postimplantation at the splenium of the corpus callosum, green fluorescent protein-labeled C6-R cells were observed primarily in either the corpus callosum or the hippocampus in the brain, and in the spinal cord they migrated more extensively in the white matter than in the grey matter. To determine whether C6-R cells retain their ability to promote neuronal migration in vivo, they were coinjected with labeled neurons into adult brain. When rat embryonic neurons were coimplanted with C6-R cells, the neurons and C6-R cells comigrated through a much larger volume than neurons alone or neurons coimplanted with fibroblasts. In brains preinjured with ibotenic acid, C6-R cells as well as coimplanted neurons distributed widely within the lesion site and migrated into adjacent brain tissue, while transplants with neurons alone were restricted primarily to the lesion site. The results suggest that radial glial cell lines can serve as a scaffold for neuronal migration that may facilitate development of experimental models for neural transplantation and regeneration.

Animals↗

Reduced tumorigenicity of rat glioma cells in the brain when mediated by hygromycin phosphotransferase.

OBJECT: A variant of C6 glioma cells, C6R-G/H cells express hygromycin phosphotransferase (HPT) and appear to have reduced tumorigenicity in the embryonic brain. The goal of this study was to investigate their reduced capacity to generate tumors in the adult rat brain. METHODS: Cell lines were implanted into rat brains and tumorigenesis was evaluated. After 3 weeks, all rats with C6 cells showed signs of neurological disease, whereas rats with C6R-G/H cells did not and were either killed then or allowed to survive until later. Histological studies were performed to analyze tumor size, malignancy, angiogenesis, and cell proliferation. Cells isolated from rat brain tumors were analyzed for mutation to HPT by testing their sensitivity to hygromycin. CONCLUSIONS: The results indicate that HPT suppresses tumor formation. Three weeks after implantation, only 44% of animals implanted with C6R-G/H cells developed tumors, whereas all animals that received C6 glioma cells developed high-grade gliomas. The C6R-G/H cells filled a 20-fold smaller maximal cross-sectional area than the C6 cells, and exhibited less malignant characteristics, including reduced angiogenesis, mitosis, and cell proliferation. Similar results were obtained in the brain of nude rats, indicating that the immune system did not play a significant role in suppressing tumor growth. The combination of green fluorescent protein (GFP) and HPT was more effective in suppressing tumorigenesis than either plasmid by itself, indicating that the GFP may protect against inactivation of the HPT. Interestingly. hygromycin resistance was lost in tumor cells that were recovered from a group of animals in which C6R-G/H cells formed tumors, confirming the correlation of HPT with reduced tumorigenicity.

Animals↗

Immunological and pathological study of anti-Ri-associated encephalopathy.

A patient with high titers of the anti-Ri antibody died 3 years after a progressive course with ataxia, opsoclonus, dementia, and peripheral neuropathy. At autopsy, no tumor was found. The nervous system exhibited severe Purkinje cell loss and contained perivascular and interstitial inflammatory infiltrates, particularly involving the brainstem. B and CD4 cells predominated in the perivascular spaces and CD8 cells in the interstitial infiltrates. Complement reactivity and natural killer cells were present and predominated in areas with more intense inflammatory infiltrates. Deposits of IgG were detected in the cytoplasm and nuclei of some neurons, particularly those in the brainstem tegmentum. The proportion of anti-Ri IgG in the total IgG extracted from various areas of the brain, serum, and cerebrospinal fluid was determined by quantitative western blot analysis. Anti-Ri reactivity was identified in immunoblots of all regions of the brain, but it predominated in basis pontis and dorsal mesencephalon. Our findings support the hypothesis of an autoimmune basis for the disorder and suggest that an antibody-mediated mechanism may play a role in its pathogenesis.

Aged↗

Nuclear localization of anti-Hu antibody is not associated with in vitro cytotoxicity.

IgG fractions of sera containing anti-Hu antibodies or control sera were incubated with Hu-positive and Hu-negative cell lines. Anti-Hu IgG specifically localized in the nucleus of Hu-positive cells. Anti-Hu-positive and control sera were incubated with Hu-positive cells and human complement or peripheral blood mononuclear cells. Hu antibody caused neither complement-mediated lysis nor augmented antibody-dependent cell-mediated cytotoxicity. Anti-Hu IgG did not affect proliferation of Hu-positive cells. Anti-Hu antibodies may not play a direct role in tissue injury in patients with paraneoplastic encephalomyeloneuropathy and anti-Hu antibodies.

Autoantibodies↗

Magnetic resonance imaging in motor neuron disease.

Magnetic resonance imaging (MRI) of the brain was evaluated in 20 patients with motor neuron disease (MND) and in a control group of 11 healthy people. Bilateral increased signal areas of various sizes in the centrum semiovale, corona radiata, internal capsule, pedunculi of midbrain, pons, medulla and even in the frontal lobe, topographically related with the corticospinal tract, were found in 8 out of 20 patients. Three out of 4 patients with progressive bulbar paralysis and 5 out of 11 cases of amyotrophic lateral sclerosis had abnormal MRI. Such MRI abnormalities have neither been found in patients with progressive muscular atrophy nor in controls, suggesting that they may be the hallmark of pyramidal tract degeneration in motor neuron disease.

Adult↗

Uveomeningoencephalitis in a human immunodeficiency virus type 2-seropositive patient.

A 35-year-old woman developed longstanding uveitis and later a uveomeningoencephalitis of unknown origin and died of toxoplasmal brain abscesses. The presence of immunological impairment, human immunodeficiency virus type 2 (HIV-2) seropositivity, and multinucleated cells in the brain led us to suspect neurotropic properties for HIV-2 similar to those of HIV-1.

Acquired Immunodeficiency Syndrome↗

Haematological changes in retinal vasculitis.

Two selected cases of retinal vasculitis, apparently of unknown aetiology, are reported; one case without any systemic or laboratory manifestation and the second case with a clinical picture similar to VKH syndrome and immunodepression. Both cases showed abnormal haematological parameters related to blood viscosity in the early and acute phases which could be manipulated by therapy. Reduction or near normalisation of these haemorrheological parameters coincided with clinical and angiographic improvement. The second case with severe immunodepression was found to be retrovirus HIV-2 positive.

Adult↗