The location and function of respiratory fibres in the second cervical spinal cord segment: respiratory dysfunction syndrome after cervical cordotomy.

After high cervical percutaneous cordotomy for pain in malignant disease, 12 patients died during sleep at postoperative intervals between 1 and 8 days. Nine died after a first cordotomy and three after a second (contralateral) procedure. All except one had known pulmonary disease before operation. The operated segment of the spinal cord (C2) was studied histologically after death. Superposition of lesion outlines made it possible to determine those parts of the lesioned areas common to all unilateral and bilateral cases respectively. All cases dying of presumed respiratory dysfunction syndrome had lesions involving the region of the anterolateral funiculus in the C2 segment containing "pain" fibres activated from the second to fifth thoracic dermatomes. The fibres whose destruction appeared to be responsible for respiratory dysfunction syndrome were completely intermingled with ascending "pain" fibres. The possibility of these fibres being afferent in function is discussed.     

Relationship between host age and persistence of Theiler''s virus in the central nervous system of mice.

This study has demonstrated that the ability of BeAn 8386 virus to persist in the central nervous system of mice declines with the increasing age of the host at the time of inoculation. Although persistent infection was established in 1-, 3-, 9-, and 40-week-old mice, there was a significant reduction in both the frequency of virus isolations and the mean virus titers in mice inoculated after 3 weeks of age. The incidence of clinical demyelinating disease (late disease) also decreased in animals infected after 3 weeks of age in parallel with the decline in virus persistence.     

Theiler''s virus infection in mice: an unusual biphasic disease process leading to demyelination.

An unusual biphasic central nervous system disease developed in 3-week-old Swiss outbred mice after intracerebral inoculation of the DA strain of Theiler's murine encephalomyelitis virus. Nine to 20 days postinfection 86% of mice became paralyzed, and approximately one-half of these animals survived. During this period neuronal necrosis and microglial proliferation were seen in thalamus, brainstem, and spinal cord. There was an initial phase of virus growth in spinal cord followed by persistent infection at a lower concentration. Virus antigen was readily found in the cytoplasm of neurons by immunofluorescent staining early in the course of infection, whereas after 30 days there was a paucity of cells containing virus antigen which were present only in the spinal cord white matter. Between 1 and 5 months, an intense mononuclear inflammatory cell lesion evolved in the spinal cord leptomeninges and white matter, which coincided with a mild gait disturbance in some surviving mice, and patchy demyelination was found in areas of inflammation. The acute gray matter pathology would appear to be the result of direct virus lytic effect. Although the late white matter lesion culminating in demyelination probably represents a cytocidal infection similar to the situation that exists in certain picornavirus carrier culture systems, a virus-induced immunopathological process merits further study.     

Mutations in the retinal guanylate cyclase (RETGC-1) gene in dominant cone-rod dystrophy

The dominant cone-rod dystrophy gene CORD6 has previously been mapped to within an 8 cM interval on chromosome 17p12-p13. The retinal- specific guanylate cyclase gene (RETGC-1), which maps to within this genetic interval and previously was implicated in Leber's congenital amaurosis, was screened for mutations within this family and in a panel of small families and individuals with various cone and cone- rod dystrophy phenotypes. A missense mutation (E837D) was identified in affected members of the CORD6 family, as well as a second missense mutation (R838C) in three other families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene to be implicated in cone-rod dystrophy and this is the first report of dominant mutations in this gene.      

Schwann cell remyelination and recurrent demyelination in the central nervous system of mice infected with attenuated Theiler's virus.

Theiler's murine encephalomyelitis virus (TMEV) infection produces a chronic demyelinating disease in mice, and myelin breakdown appears to be immune-mediated. By using an attenuated TMEC strain, WW virus, to infect mice, the course of the disease was slowed and the severity of the inflammatory and glial responses were reduced. In this circumstance, most of the demyelinating lesions showed extensive remyelination, predominantly by Schwann cells. In addition, it was demonstrated that there was recurrent demyelinating activity in the central nervous system (CNS) of infected animals. It is suggested that the rapidity and intensity of demyelinating lesions may influence the potential for remyelination and that Schwann cell participation may be a more important mechanism of myelin repair than it is now thought to be. The fact that there is a recurrent demyelination in TMEV infection increases its relevance as an experimental animal model for multiple sclerosis.     

A noninvasive stimulus onset device for use in gustatory research

A simple device for precise, noninvasive measurement of stimulus onset time in gustatory research is described. This device utilizes an ultrafast, self-heated, micro-thermistor to sense the cooling effect of the fluid stream that bathes the tongue.     

Techniques of exposure for the stiff total knee

Primary and revision total knee arthroplasty have become common orthopaedic procedures. The operating surgeon, at times, may be faced with a difficult surgical case due to soft tissue contractures or bone deformities. A review of multiple surgical techniques using soft tissue releases and osteotomies are presented including their potential complications. Although these techniques are aimed at the atypical operative case, the operating surgeon may utilize them for ‘routine’ exposures as well. Importance is focused on the functional integrity of the knee extensor mechanism.