Astrocyte and microglial motility in vitro is functionally dependent on the hyaluronan receptor RHAMM

RHAMM (Receptor for Hyaluronic Acid Mediated Motility) has been identified as a receptor for the extracellular matrix component hyaluronan (HA) and was recently shown to be essential for the locomotion of normal and transformed peripheral cells. Until now the potential role of RHAMM in the motility of neural-derived cells has not been investigated. Here, we report that cultured primary astrocytes, astrocyte cell lines, and microglia express this receptor and exhibit RHAMM-dependent motility. Immunocytochemical localization of RHAMM showed that it was often present as aggregates at the periphery of cells in contact with one another or concentrated on protruding processes of isolated cells. Glial cells contained 50 and 72 kDa forms of RHAMM, and both of these forms were found to have HA binding capacity. Time lapse imaging of cell locomotion revealed a significant inhibition of motility and process elongation by neutralizing anti-RHAMM antibodies and by peptides corresponding to the HA binding domains of RHAMM. These results demonstrate that RHAMM serves a role in glial cell locomotion in vitro and provide the basis for investigations of the motile behavior of glial cells in vivo after CNS injury.     

Schwann cell invasion of the conus medullaris: case report

As Schwann cells possess regenerative capabilities there is intense interest concerning their role in central nervous system (CNS) regeneration. We report on a case of an intramedullary schwannoma involving the conus medullaris and spinal cord above it. We discuss the possible origin of these cells and the mechanisms by which these cells may invade the CNS. We offer imaging and discuss experimental studies to support our hypothesis. This case concerns a 48-year-old man, who presented with a 6-month history of bilateral lower extremity weakness. Magnetic resonance imaging (MRI) revealed an intramedullary tumour extending from the conus to T11. At operation, following laminectomy and durotomy, a schwannoma was dissected free from the conus. Total gross resection of tumour was achieved. The patient made an uneventful and full recovery. This case shows that Schwann cells can invade the CNS. Manipulation of the transitional zone astrocytic barrier may offer a potential avenue for Schwann cells to enter the CNS in pathological states.     

Epidural Spinal Cord Infiltration: A Rare Complication of Acute Myeloblastic Leukaemia

Epidural infiltration by leukemic cells in Acute Non Lymphoblastic Leukemia (ANLL), and extradural granulocytic sarcomas as a cause of spinal cord compression are extremely rare phenomena. Very few cases have been recorded in the literature. In this brief case report we describe a young patient with acute myeloblastic leukemia (M4, FAB) who presented with sudden spinal cord compression during relapse after bone marrow transplantation. The literature on this subject is also reviewed.     

Effect of electric and chemical stimulation of the raphe obscurus on phrenic nerve activity in the cat

The effect of electrical and chemical (l-glutamate) stimulation of the raphe obscurus on phrenic nerve activity was examined in the cat. Phrenic nerve activity was recorded from a C5 nerve root in anesthetized, paralyzed and artificially ventilated cats. Neural discharge was quantitated by integrating the phrenic nerve activity. The respiratory frequency was determined from the integrated nerve signal. Focal electrical stimulation (18–144 μA; 5–40 Hz; 100 μs pulse duration) resulted in significant (P < 0.05) increases in both integrated phrenic nerve (IPN) amplitude and respiratory frequency. These changes were dependent upon current intensity and frequency of stimulation. The largest increases in IPN amplitude and respiratory frequency were47 ± 17%and146 ± 8%, respectively. To insure that the changes in integrated phrenic nerve activity (IPNA) were the result of stimulation of cell bodies and not axons of passage,l-glutamate (100, 200 nmol) was microinjected (100 nl) into the raphe obscurus. Significant (P < 0.05) dose-related changes occurred in integrated phrenic nerve amplitude with an increase of44 ± 13% at 100 nmol and80 ± 13% at 200 nmoll-glutamate. No significant increase in respiratory frequency was observed withl-glutamate microinjection. The results suggest that the raphe obscurus may be involved in respiratory control.     

Mental retardation,structural anomalies of the central nervous system,anophthalmia and abnormal nares: A new MCA/MR syndrome of unknown cause

We report on 2 unrelated Brazilian girls, born to nonconsanguineous parents, and presenting structural central nervous system defects, hydrocephaly, macrocephaly, craniosynostosis, prominent forehead, anophthalmia, and abnormal nares. These patients may have a previously undescribed recurrent-pattern cerebro-oculo-nasal syndrome. © 1993 Wiley-Liss, Inc.     

Localization of tissue plasminogen activator mRNA in adult rat brain

The distribution of tissue plasminogen activator (tPA) messenger RNA in rat brain was studied using in situ hybridization with ³⁵S UTP-labeled RNA probes derived from a fulllength tPA cDNA. Sense strand controls produced low, even backgrounds, with small elevations in the hippocampus. Full-length antisense probes produced strong signals over cerebral ventricular ependyma (including ependyma of the subcommissural organ), meninges, blood vessels, and Purkinje cell layer of the cerebellum, as well as strong signals over scattered cells throughout the brain. Some of these scattered labeled cells were large with lightly stained nuclei, while others were small with darkly stained nuclei. The large labeled cells, which were probably neurons, constituted 8% and 8% of cells in the brain stem and neocortex, respectively, and 100% of Purkinje cells. The small cells, which were present in all areas of the brain, constituted 3–11 % of cells in individual brain areas.     

A sleep disturbance in high risk for SIDS infants

A developmentally immature sleep pattern has been identified in infants with a recent history of an unexplained life-threatening episode of sleep apnoea who are considered at risk for SIDS. In these infants there is a persistence of Sleep Onset REM Periods (SOREMPS) after prolonged wakefulness when compared to controls matched for age, sex, birthweight and race. This sleep characteristic has not been previously reported.     

Neuroradiology and clinical aspects of Usher syndrome

We describe the neurological evaluation and MRI analysis of 30 patients, belonging to 16 families with Usher syndrome (US) type I and type II (US1 and US2). In addition to the classic visual and audiological abnormalities seen in these patients, we observed abnormal gait in 88.9% of US1 and in 66.7% of US2 patients and abnormal coordination in 33.4% of US1, and in 58.3% of US2. Borderline mental retardation, depression or bipolar affective disorder were observed in 16.7% of US1 and 33.3% of US2 patients. MRI analysis showed cerebellar abnormalities in 50% of US 1 and 75% of US2 patients, but no clear correlation was observed between structural abnormalities and clinical findings. A pattern for the MRI classification of US patients is suggested.     

The Effects of Ante- and Postnatal Hypoxia on the Central Nervous System and Their Correction with Peptide Hormones

Ante- and postnatal hypoxia significantly worsened the postnatal development of animals. The posthypoxic behavioral model included hyperactivity and decreased learning ability, these being typical manifestations of attention deficit disorder. A peptide constellation prevented and significantly improved posthypoxic postnatal development and eliminated the majority of negative behavioral changes.