Fungal infection in neural tissue of patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease and the main cause of motor neuron pathology. The etiology of the disease remains unknown, and no effective therapy exists to halt the disease or improve the quality of life. Here, we provide compelling evidence for the existence of fungal infection in ALS. Immunohistochemistry analysis using a battery of antifungal antibodies revealed fungal structures such as yeast and hyphae in the motor cortex, the medulla and the spinal cord, in eleven patients with ALS. Some fungal structures were localized intracellularly and even intranuclearly, indicating that this infection is not the result of post-mortem colonization. By contrast, this burden of fungal infection cannot be observed in several CNS areas of control subjects. PCR analysis and next generation sequencing of DNA extracted from frozen neural tissue identified a variety of fungal genera including Candida, Malassezia, Fusarium, Botrytis, Trichoderma and Cryptococcus. Overall, our present observations provide strong evidence for mixed fungal infections in ALS patients. The exact mixed infection varies from patient to patient consistent with the different evolution and severity of symptoms in each ALS patient. These novel findings provide a logical explanation for the neuropathological observations of this disease, such as neuroinflammation and elevated chitinase levels, and could help to implement appropriate therapies.

Intramedullary lesions of the conus medullaris: differential diagnosis and surgical management.

The medullary conus represents a distinct entity of the spinal cord regarding its anatomical, clinical and microsurgical features. An overview of the pathologic processes of this region is provided. Epidemiological, clinical and neuroradiological characteristics of neoplastic (glial tumors, non-glial tumors, metastasis, primary melanomas) and non-neoplastic lesions (granulomatous lesions, abscess, parasitic infections, vascular, demyelinating and dysembryogenetic lesions) are discussed. Main MR imaging characteristics used to differentiate neoplastic from non-neoplastic lesions consist in pathological spinal cord expansion, gadolinium-enhancement and tumoural cyst formation. Management strategies differ substantially, depending on the kind of lesion. According to the suspected pathological entity radical resection, biopsy or conservative treatments are reasonable options. Intraoperative electrophysiological monitoring is a fundamental part of the surgical setting.

Borrelia burgdorferi transcriptome in the central nervous system of non-human primates.

Neurological symptoms are common manifestations of Lyme disease; however, the paucibacillary nature of the spirochete in this environment has precluded a molecular analysis of the spirochete in the CNS. We have now adapted differential expression analysis by using a custom-amplified library (DECAL) in conjunction with Borrelia burgdorferi whole-genome and subgenome arrays to examine in vivo gene expression by B. burgdorferi in a non-human primate (NHP) model of neuroborreliosis. The expression profile of B. burgdorferi was examined in the CNS and heart of steroid-treated and immunocompetent NHPs. Eighty-six chromosomal genes and 80 plasmid-encoded genes were expressed at similar levels in the CNS and heart tissue of both immunocompetent and steroid-treated NHPs. The expression of 66 chromosomal genes and 32 plasmid-encoded genes was increased in the CNS of both immunocompetent and steroid-treated NHPs. It is likely that the expression of these genes is governed by physiological factors specific to the CNS milieu. However, 83 chromosomal and 114 plasmid-encoded genes showed contrasting expression profiles in steroid-treated and immunocompetent NHPs. The effect of dexamethasone on the immune status of the host as well as on the host metabolic pathways could contribute to these differences in the B. burgdorferi transcriptome. Results obtained herein underscore the complex interplay of host factors on B. burgdorferi gene expression in vivo. The results provide a global snapshot of the spirochetal transcriptome in the CNS and should spur the design of experiments aimed at understanding the molecular basis of neuroborreliosis.

Direct detection of leptospiral material in human postmortem samples.

Leptospiral culture, direct immunofluorescence, and the polymerase chain reaction (PCR) were used to detect leptospiral material in postmortem specimens collected from eight patients who died of leptospirosis. Diagnosis of leptospiral infection was based on clinical summary (premortem) and confirmed by serological analysis and/or culture of leptospires. Leptospiral culture was the least sensitive technique, yielding two isolates (3%) from 65 samples. Both isolates were from the aqueous humour and cerebrospinal fluid of the same patient. Direct immunofluorescence was of intermediate sensitivity for detection of leptospires, confirming the presence of leptospires in 11% (2 of 18) of tissue samples from three patients. PCR analysis was the most sensitive technique for detection of leptospiral material in tissue samples, being positive in 20% (11 of 56) of samples from eight patients. Both samples (cerebellum and liver) positive by immunofluorescence were also positive by PCR. The sensitivity of the PCR assay was 1-10 leptospires ml(-1) sample, and the assay was specific for Leptospira pathogenic species. Multi-system involvement was indicated based on successful amplification of leptospiral DNA from more than one tissue sample, which corroborated with the clinical and pathologic findings. The results suggest that in acute and/or fatal leptospirosis, the pathogenesis of the pathologic features are related to the presence of the organisms in the tissues. In conclusion, PCR combined with serology appears to be a useful tool for diagnosis of leptospirosis and may be invaluable in epidemiological studies.

Intramedullary brain stem cyst and trapped IV ventricle after infection with Listeria monocytogenes.

We present the rare case of a girl surviving intrauterine listeria brain stem meningoencephalitis, who subsequently developed hydrocephalus, a trapped IV ventricle and an intramedullary cyst. Such cases have been reported only infrequently, and in earlier cases modern imaging studies were not available. Magnetic resonance imaging has been helpful in our patient to delineate the lesions and plan further treatment.

Congenital dermal sinus associated with an abscessed intramedullary epidermoid cyst in a child: case report and review of the literature.

A 16-month-old male infant presented with paraparesis and a high thoracic skin dimple. After myelography the child underwent complete surgical removal of the dermal sinus and of an abscessed tumor located within the cervicothoracic cord. Histological study showed that the lesion was an intramedullary epidermoid cyst. Only four descriptions have previously been published of dermal sinuses associated with intramedullary epidermoids, three of them complicated by intramedullary abscesses. This appears to be the first report in the current literature of the association of a dermal sinus and an infected intramedullary epidermoid occurring out of the confines of the lumbosacral region.

Magnetic resonance image findings of spinal intramedullary abscess caused by Candida albicans: case report.

We present the clinical, serological, and radiological features of a patient with a spinal intramedullary abscess caused by Candida albicans. Antimycotic treatment was successful, and no neurosurgical approach was necessary.

Innervation of the heart and its central medullary origin defined by viral tracing.

The vagus nerve exerts a profound influence on the heart, regulating the heart rate and rhythm. An extensive vagal innervation of the cardiac ventricles and the central origin and extent of this innervation was demonstrated by transynaptic transport of pseudorabies virus with a virulent and two attenuated pseudorabies viral strains. The neurons that innervate the ventricles are numerous, and their distribution within the nucleus ambiguus and dorsal motor nucleus of the vagus is similar to that of neurons innervating other cardiac targets, such as the sino-atrial node. These data provide a neuroanatomical correlate to the physiological influence of the vagus nerve on ventricular function.

Central nervous system innervation of the penis as revealed by the transneuronal transport of pseudorabies virus.

Transneuronal tracing techniques were used in order to identify putative spinal interneurons and brainstem sites involved in the control of penile function. Pseudorabies virus was injected into the corpus cavernosus tissue of the penis in rats. After a four day survival period, rats were perfused with fixative and virus-labelled neurons were identified by immunohistochemistry. Postganglionic neurons were retrogradely labelled in the major pelvic ganglia. In the spinal cord, sympathetic and parasympathetic preganglionic neurons were labelled transneuronally. Presumptive interneurons were also labelled in the lower thoracic and lumbosacral spinal cord in locations consistent with what is currently known about such interneurons. In the brainstem, transneuronally labelled neurons were found in the medulla, pons and hypothalamus. Regions consistently labelled included the nucleus paragigantocellularis, parapyramidal reticular formation of the medulla, raphe pallidus, raphe magnus, A5 noradrenergic cell group, Barrington's nucleus and the paraventricular nucleus of the hypothalamus. This study confirmed previous studies from our lab and others concerning the preganglionic and postganglionic neurons innervating the penis. The number, morphology and location of these neurons were consistent with labelling seen following injection of conventional tracers into the penis. The brainstem nuclei labelled in this study were also consistent with what is currently known about the brainstem control of penile function. The labelling appeared to be highly specific, in that descending systems involved in other functions were not labelled. These results provide further evidence that the pseudorabies virus transneuronal tracing technique is a valuable method for identifying neural circuits mediating specific functions.

Transneuronal labelling of neurons in rabbit brain after injection of herpes simplex virus type 1 into the renal nerve.

We mapped the distribution of virus-labelled neurons in the brain after injection of Herpes simplex virus type 1 (HSV1) into the rabbit renal nerve. Seven days after injection, labelled neurons were observed in four brain regions, the rostral ventrolateral medulla (47 +/- 3% of neurons), the A5 area of the lower pons (38 +/- 4%), the caudal raphe nuclei and the parapyramidal area of the medulla (13 +/- 2%), and the paraventricular nucleus of the hypothalamus (1 +/- 1%). In the rostral ventrolateral medulla approximately one half of the HSV1-labelled neurons also contained tyrosine hydroxylase, characterizing them as C1 neurons. In the A5 area virtually all HSV1-labelled neurons also contained tyrosine hydroxylase. In the raphe nuclei and the parapyramidal area 47% of HSV1-positive neurons contained serotonin. The distribution of labelled neurons was similar to that observed after injection of HSV1 into the adrenal gland.

Spongiform encephalopathy in a captive puma (Felis concolor).

A captive adult puma developed ataxia, a hypermetric gait and whole body tremor. The signs progressed over a period of six weeks. Histopathological examination following euthanasia demonstrated spongiform encephalopathy, gliosis and mild non-suppurative meningoencephalitis. Immunostaining with a polyclonal antiserum revealed prion protein (PrP) associated with these changes in sections of cervical spinal cord and medulla. This is the first confirmed case of a scrapie-like spongiform encephalopathy described in a non-domestic cat in the United Kingdom.

Natural scrapie: detection of fibrils in extracts from the central nervous system of sheep.

Extracts from the cervical spinal cord and from the medulla, thalamus, cerebellum and cerebral cortex of the brains of 10 sheep, histopathologically confirmed as cases of scrapie, were examined by electron microscopy for the presence of scrapie-associated fibrils. Characteristic fibrils were observed in all the extracts except for that from the thalamus of one sheep. No fibrils were found in any extracts from three control sheep. A comparison of these results with a similar study of 22 cases of bovine spongiform encephalopathy (BSE) suggests that in cases of scrapie the area of the brain chosen for the detection of fibrils is less critical than in cases of BSE, in which fibrils are more readily extracted from areas of the brain stem.

Use of type 1/type 2 chimeric polioviruses to study determinants of poliovirus type 1 neurovirulence in a mouse model.

We previously described the characteristics of a type 1/type 2 (PV-1/PV-2) chimeric poliovirus, v510, which contains the six amino acids specific for PV-2 in the B-C loop of VP1. This virus was found to be mouse-adapted, as PV-2 and in contrast with PV-1. Determinants of host range were studied in detail and are reported here. PV-1/PV-2 chimeras containing partial PV-1----PV-2 substitutions in the B-C loop of VP1 were obtained by making use of a mutagenesis cartridge on PV-1 cDNA. Analysis of mouse neurovirulence of these chimeras, when correlated with the three-dimensional structure of the v510 capsid, revealed that PV-2 residues important for mouse tropism are those which determine the particular conformation of the B-C loop of VP1 in v510. The mutation of the adenine residue at position 480 of the 5' noncoding region into a guanine residue has been shown to be an important determinant of PV-1 attenuation in monkeys. We show that introduction of this mutation in the v510 genome results in a virus which is partially attenuated for mice. This suggests that analysis of genomic determinants important for PV-1 neurovirulence could be carried out in a mouse model by making use of a mouse-adapted PV-1/PV-2 chimera.