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.

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.

Effect of phosphonoformate on symptomatic genital herpes simplex virus type 2 infection of guinea pigs.

Using a guinea pig model of genital herpes simplex virus (HSV) type 2 infection, phosphonoformate treatment initiated after the onset of symptoms had a therapeutic effect on the outcome of disease. Severity of disease, viral shedding, and HSV-induced cellular changes in vaginal cytology were significantly reduced in drug-treated animals as compared to sham-treated animals, although virus was readily detected in the nervous system of animals from both groups. The percentage of animals harboring latent virus in their dorsal root ganglia was approximately the same in both drug-treated and sham-treated animals. No drug toxicity was found.

The response of colostrum-deprived, specific pathogen-free pigs to experimental infection with Teschen disease virus.

The clinical response to Teschen disease and the excretion and rate of virus distribution in tissues of colostrum-deprived, specific pathogenfree pigs was determined. Severe, mild, and clinically inapparent responses to the disease were noticed following simultaneous intracranial and intranasal infections. Fourteen-day-old pigs reacted more severely to infection than 21-day-old pigs. The virus was detected in feces 2-3 days following infection but not in stools of surviving pigs 30 days after infection. The highest concentration of virus occurred during the incubation period and before onset of paralysis; the lowest concentrations were found during terminal disease stages. In tissues collected before or immediately after death of pigs, Teschen disease virus was found in several visceral organs but not in blood, urine or urinary bladder tissue. Virus yield was highest in brain and spinal cord tissues. Highest virus concentration was found in the cervical thoracic portions of the spinal cord, thalamus and cerebellum. Other aspects of the clinical disease are discussed.