Serum matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 levels in non-herpetic acute limbic encephalitis.

The pathogenesis of non-herpetic acute limbic encephalitis (NHALE) has been not clear. Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) play important roles in the function of the blood-brain barrier. We measured the serum concentrations of MMP-9 and TIMP-1 by using enzyme-linked immunosorbent assay (ELISA) in 23 patients with NHALE in the acute and convalescent stages. Serum MMP-9 concentrations and ratios of serum MMP-9/TIMP-1 were significantly higher (1) in patients with NHALE in acute and convalescent stages than in control patients (all P < 0.001); (2) in patients with NHALE at the acute stage compared with those at the convalescent stage (P = 0.004, and P = 0.014, respectively). In contrast, serum TIMP-1 concentrations were significantly lower in patients with NHALE in the acute and convalescent stages than in control patients (both P < 0.001) but did not differ in patients with NHALE in the acute and convalescent stages. Our preliminary study suggests that the prolonged imbalance of MMP-9 and TIMP-1 is associated with the pathogenesis of NHALE.

Tioman virus infection in experimentally infected mouse brain and its association with apoptosis.

Tioman virus is a newly described bat-urine derived paramyxovirus isolated in Tioman Island, Malaysia in 2001. Hitherto, neither human nor animal infection by this virus has been reported. Nonetheless, its close relationship to another paramyxovirus, the Menangle virus which had caused diseases in humans and pigs [Philbey, A.W., Kirkland, P.D., Ross, A.D., Davis, R.J., Gleeson, A.B., Love, R.J., Daniels, P.W., Gould, A.R., Hyatt, A.D., 1998. An apparently new virus (family Paramyxoviridae) infectious for pigs, humans, and fruit bats. Emerg. Infect. Dis. 4, 269-271], raises the possibility that it may be potentially pathogenic. In this study, mice were experimentally infected with Tioman virus by intraperitoneal and intracerebral routes, and the cellular targets and topographical distribution of viral genome and antigens were examined using in situ hybridization and immunohistochemistry, respectively. The possible association between viral infection and apoptosis was also investigated using the TUNEL assay and immunohistochemistry to FasL, Caspase-3, Caspase-8, Caspase-9 and bcl-2. The results showed that Tioman virus inoculated intracerebrally was neurotropic causing plaque-like necrotic areas, and appeared to preferentially replicate in the neocortex and limbic system. Viral infection of inflammatory cells was also demonstrated. TUNEL and Caspase-3 positivity was found in inflammatory cells but not in neurons, while FasL, Caspase-8 and Caspase-9 were consistently negative. This suggests that neuronal infection was associated with necrosis rather than apoptosis. Moreover, the data suggest that there may be an association between viral infection and apoptosis in inflammatory cells, and that it could, at least in part, involve Caspase-independent pathways. Bcl-2 was expressed in some neurons and inflammatory cells indicating its possible role in anti-apoptosis. There was no evidence of central nervous system infection via the intraperitoneal route.

A role for endocannabinoids in viral-induced dyskinetic and convulsive phenomena.

Dyskinesias and seizures are both medically refractory disorders for which cannabinoid-based treatments have shown early promise as primary or adjunctive therapy. Using the Borna disease (BD) virus rat, an animal model of viral encephalopathy with spontaneous hyperkinetic movements and seizure susceptibility, we identified a key role for endocannabinoids in the maintenance of a balanced tone of activity in extrapyramidal and limbic circuits. BD rats showed significant elevations of the endocannabinoid anandamide in subthalamic nucleus, a relay nucleus compromised in hyperkinetic disorders. While direct and indirect cannabinoid agonists had limited motor effects in BD rats, abrupt reductions of endocannabinoid tone by the CB1 antagonist SR141716A (0.3 mg/kg, i.p.) caused seizures characterized by myoclonic jerks time-locked to periodic spike/sharp wave discharges on hippocampal electroencephalography. The general opiate antagonist naloxone (NLX) (1 mg/kg, s.c.), another pharmacologic treatment with potential efficacy in dyskinesias or L-DOPA motor complications, produced similar seizures. No changes in anandamide levels in hippocampus and amygdala were found in convulsing NLX-treated BD rats. In contrast, NLX significantly increased anandamide levels in the same areas of normal uninfected animals, possibly protecting against seizures. Pretreatment with the anandamide transport blocker AM404 (20 mg/kg, i.p.) prevented NLX-induced seizures. These findings are consistent with an anticonvulsant role for endocannabinoids, counteracting aberrant firing produced by convulsive agents, and with a functional or reciprocal relation between opioid and cannabinoid tone with respect to limbic convulsive phenomena.

Influenza A virus infection causes alterations in expression of synaptic regulatory genes combined with changes in cognitive and emotional behaviors in mice.

Epidemiological studies have indicated a link between certain neuropsychiatric diseases and exposure to viral infections. In order to examine long-term effects on behavior and gene expression in the brain of one candidate virus, we have used a model involving olfactory bulb injection of the neuro-adapted influenza A virus strain, WSN/33, in C57Bl/6 mice. Following this olfactory route of invasion, the virus targets neurons in the medial habenular, midline thalamic and hypothalamic nuclei as well as monoaminergic neurons in the brainstem. The mice survive and the viral infection is cleared from the brain within 12 days. When tested 14-20 weeks after infection, the mice displayed decreased anxiety in the elevated plus-maze and impaired spatial learning in the Morris water maze test. Elevated transcriptional activity of two genes encoding synaptic regulatory proteins, regulator of G-protein signaling 4 and calcium/calmodulin-dependent protein kinase IIalpha, was found in the amygdala, hypothalamus and cerebellum. It is of particular interest that the gene encoding RGS4, which has been related to schizophrenia, showed the most pronounced alteration. This study indicates that a transient influenza virus infection can cause persistent changes in emotional and cognitive functions as well as alterations in the expression of genes involved in the regulation of synaptic activities.

Investigation of the complex descending innervation of the dorsal cochlear nucleus in the rat: a transneuronal tract-tracing study using pseudorabies virus.

The afferent neuronal connections of the dorsal cochlear nucleus were investigated in rats by using a trans-synaptic retrograde tract-tracing method. The neurotropic viral tracer, the Bartha strain of the pseudorabies virus was stereotaxically injected into the dorsal cochlear nucleus, ipsilaterally. Neurons, which project directly or indirectly (one or multiple relays by other neurons) to the dorsal cochlear nucleus were infected and visualized by immunohistochemistry. Labeled neurons were found in each components of the auditory pathway, some of the monoaminergic cell groups in the lower brainstem, the hypothalamus and in some limbic areas.

Progressive postnatal assembly of limbic-autonomic circuits revealed by central transneuronal transport of pseudorabies virus.

The development of neuronal projections to a target and the establishment of synaptic connections with that target can be temporally distinct events, which typically are distinguished by functional assessments. We have applied a novel neuroanatomical approach to characterize the development of limbic forebrain synaptic inputs to autonomic neurons in neonatal rats. Transneuronal labeling of preautonomic forebrain neurons was achieved by inoculating the ventral stomach wall with pseudorabies virus (PRV) on postnatal day 1 (P1), P4, or P8. In each age group, PRV-positive neurons were present in autonomic and preautonomic regions of the spinal cord and brainstem 62-64 hr after inoculation. Transneuronal forebrain labeling in rats injected on P8 was similar to the transneuronal labeling reported previously in adult rats and included neurons in the medial and lateral hypothalamus, amygdala, bed nucleus of the stria terminalis, and visceral cortices. However, no cortex labeling and only modest amygdala and bed nucleus labeling were observed in rats injected with PRV on P4, and only medial hypothalamic labeling was observed in rats injected on P1. Additional tracing experiments involving central injections of PRV or cholera toxin beta indicated that lateral hypothalamic and telencephalic regions projected to the medullary dorsal vagal complex several days before establishing synaptic connections with gastric-related autonomic neurons. These results demonstrate a novel strategy for evaluating synaptic connectivity in developing neural circuits and show a temporally segregated postnatal emergence of medial hypothalamic, lateral hypothalamic, and telencephalic synaptic inputs to central autonomic neurons.

Spread of measles virus through axonal pathways into limbic structures in the brain of TAP1 -/- mice.

The spread of measles virus into the brain was studied exploiting the olfactory pathway, which represents an important route of neuroinvasion by viruses. The virus was injected into the main olfactory bulb of wild-type mice and mice with disrupted TAP1 gene (TAP refers to the Transporter associated with Antigen Presentation), which codes for products essential for the cell-mediated immune response. Virus invasion was monitored for 4 weeks by immunohistochemistry. The distribution of measles virus was found to be restricted to brain areas connected with the olfactory bulbs. However, in the wild-type mice there was a marked infiltration of lymphocytes in the infected brain structures, and the virus did not pass beyond the piriform cortex. In the TAP1 -/- mice the virus spread more extensively along olfactory projections into the limbic system and monoaminergic brainstem neurons. Infected mice of both types developed seizures, which may have been focally evoked from the piriform cortex. This study provides evidence that measles virus can spread through axonal pathways in the brain. The findings obtained in the gene-manipulated mice point out that a compromised immune state of the host may potentiate targeting of virus to the limbic system through olfactory projections.

[Ocular manifestations of hepatitis B]. / Manifestari oculare la bolnavi cu hepatita cu virus B.

We have examined 87 patients with chronic diffuse liver diseases with viral etiology and 20 healthy patients with ophthalmological, immunological and biochemical methods. It was established that liver pathology produced by hepatitis B virus give exchanges in the conjunctival and perilimbic circulation of the corneal sensitivity, retinal and optic nerve dysfunctions and also complicated cataract. Clinical symptoms in ophthalmopathology are amplify with the liver pathology progression and it is associated with the autoimmune reactions development, underlined by the antigens against eye tissues, and by the biochemical seric and local (lacrimal) parameters. The changes in eye structures were found at young and middle age patients, fact which indicate the social aspect of the problem and the necessity of their observation. In the vasoactive product "Cavinton" used in the complex treatment of the liver viral pathology it was established the possibility of pharmacologic correction of the pathologic changes in the ocular microcirculation and optic system.

Survey of herpes simplex virus infections of the central nervous system, including acute disseminated encephalomyelitis, in the Kyushu and Okinawa regions of Japan.

We analysed data from 27 patients with herpes simplex virus (HSV) infections of the central nervous system (CNS) found in a 1990-1992 survey in Kyushu and Okinawa, Japan. Patients ranged in age from one year to 70 years, with peaks seen in the 20s and 50s. Temporal lobe-limbic encephalitis was the most common HSV infection (13 patients), followed by meningitis (5), diffuse encephalitis (4), disseminated encephalomyelitis (ADEM) (3) and brain stem encephalitis (2). Another three patients with non-herpetic, non-paraneoplastic acute limbic encephalitis were presented. Our study indicates that HSV infection can course ADEM, although temporal lobe-limbic encephalitis or meningitis are more common. The early diagnosis of HSV-related ADEM is important because of the efficacy of the timely administration of corticosteroids.

Spatial recognition memory deficits without notable CNS pathology in rats following herpes simplex encephalitis.

Survivors of herpes simplex encephalitis (HSE) experience intellectual impairment and an inability to store and recall information. Because the temporal lobes and associated limbic structures are central to storage and retrieval of memories, and are predominantly affected in adult HSE, injury to these areas is postulated to cause behavioral and learning disabilities. A previous study (Beers et al., 1993) demonstrated that intranasal inoculation of Lewis rats with herpes simplex virus type-1 (HSV-1) induced acute partial complex seizures, and hemorrhagic and inflammatory lesions of the hippocampus and entorhinal cortex. Consequently, it was of interest to determine whether rats that had recovered from HSE had limbic system-associated memory impairments. Therefore, rats were evaluated when signs and symptoms of encephalitis were no longer apparent using an eight arm radial maze to assess the acquisition and retention of learned information. An allocentric-spatial location paradigm revealed HSV-1 infected rats performed at chance levels on both acquisition and retention which were statistically different from sham-inoculated controls. However, using an egocentric-spatial left/right discrimination task, infected rats performed statistically similar to sham-inoculated controls. Furthermore, HSV-1 nucleic acids were detected in the nuclei of neurons within the hippocampus and entorhinal cortex using in situ hybridization techniques. Of interest was the observation that rats with learning and memory deficits had no apparent histopathological or immunocytochemical evidence of antecedent CNS infection. This is the first experimental demonstration that HSV-1 can cause behavioral impairments in the absence of obvious inflammatory injury to the temporal lobe memory system.