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Biomedical subjects

J R Baringer

Publications and source records attributed to J R Baringer.

At least 19 recordsLinked to original sources
PubMed1979

Progressive myelopathy due to extramedullary hematopoiesis: case report and review of the literature.

Extramedullary hematopoiesis (EMH) in the spinal epidural space is a rare but treatable cause of progressive paraparesis in patients with a variety of hematological and systemic disorders. We report a case of extensive thoracic epidural EMH causing progressive spastic paraparesis in a patient with agnogenic myeloid metaplasia. The literature describes 11 additional cases of myelopathy due to epidural EMH. All patients had EMH in the midthoracic region with elevated cerebrospinal fluid protein and abnormal spine roentgenograms or myelograms. Treatment with decompressive laminectomy, radiation therapy, or both, resulted in marked or complete recovery in 7 of 10 patients. Patients who develop paraparesis and who have a disorder associated with EMH should be evaluated rapidly for this treatable condition.

Humans↗
PubMed1979

Host defenses in herpes simplex infections of the nervous system: effect of antibody on disease and viral spread.

BALB/c mice passively immunized with antibody to herpes simplex virus type 1 and challenged in the footpad with 10(5.7) plaque-forming units of herpes simplex virus type 1 were shown to be protected from neurological disease and death compared with control mice treated with normal serum or antibody to Sindbis virus. One hundred percent of untreated mice had virus recoverable from dorsal root ganglia by 48 h after infection. Whereas amputation of the infected limb at 48 h had no effect, antibody administration (resulting in titers of 1:8 and 1:16) was found to prevent acute neurological disease if administered no later than 48 h after infection. Antibody also restricted the extent of latent infection in the lumbosacral ganglia. The data provide strong evidence that antibody is effective in preventing spread of virus both in the peripheral nervous system and in central nervous system (spinal cord) tissue.

Animals↗
PubMed1979

Morphology of central nervous system disease in immunosuppressed mice after peripheral herpes simplex virus inoculation. Trigeminal root entry zone.

Inoculation of mice and rabbits on the cornea with herpes simplex type 1 virus has been shown to cause an ascending infection of the trigeminal nerve, ganglion, and descending tract within the brainstem (2, 3, 7). A discrete, destructive, and primarily demyelinative lesion is seen on the central nervous system side of the trigeminal root entry zone 5 to 8 days after infection (8, 15, 16). This study, utilizing Swiss mice, demonstrated that immunosuppression with cyclophosphamide prior to infection with herpes simplex type virus causes a marked reduction of the mononuclear infiltrate within the central nervous system and a significant decrease in myelin destruction when compared with the infected, nonimmunosuppressed control animals. The content of virus in the brainstem was similar in both groups by day 8 as were the neutralizing antibody titers to herpes simplex type 1 virus. These results suggest that the cellular response plays a definitive role in the destruction of central nervous system tissue after peripheral infection with herpes simplex type 1 virus.

Animals↗
PubMed1978

Partial purification and evidence for multiple molecular forms of the scrapie agent.

A procedure for the partial purification of the scrapie agent from mouse spleen was developed based on its sedimentation profile. Differential centrifugation and detergent treatment with sodium deoxycholate yielded a fraction designated "P5" which was enriched for scrapie infectivity approximately 20-fold with respect to cellular protein. The P5 fraction was devoid of cellular membranes but heavily contaminated with ribosomes as judged by electron microscopy. On centrifugation of the fraction P5 to near equilibrium in a sucrose gradient scrapie infectivity was distributed over a range of densities from 1.08 to 1.30 g/cm3. Parallel rate-zonal analysis showed that the infectivity was distributed over a range of particle sizes with s20.w values from approximately 40 S to greater than 500 S. Incubation of P5 at 37 or 80 degrees C, under conditions that disrupt ribosomes, dramatically altered the rate-zonal gradient profile of the agent. Under these conditions, the agent sedimented as particles with s20.w greater than 500 S. The apparent heterogeneity of the scrapie agent with respect to both size and density and its ability to shift from one form to another suggest that the agent may contain hydrophobic domains on its surface.

Animals↗
PubMed1978

Experimental scrapie in mice: ultrastructural observations.

Scrapie, kuru, and Creutzfeldt-Jakob disease are characterized by a similar spongiform pathology, prolonged incubation periods, and an agent with unique physical, chemical, and biological properties. Swiss mice were inoculated with the scrapie agent and sacrificed three to five months later for light and electron microscopy. At three months, small vacuoles were seen within the neuropil of the cerebral cortex and basal ganglia. By the fifth month these vacuoles had increased in number and size and were accompanied by moderate astrocytic proliferation. The brainstem, cerebellum, and spinal cord showed variable changes of much less intensity. Many dilated postsynaptic processes contained osmiophilic particles in random or crystalline arrays. The particles, measuring approximately 23 nm in diameter, appeared consistently in postsynaptic processes of brain from scrapie-infected mice, were lacking in controls, and were a size consistent with sedimentation and filtration data for the scrapie agent. Whether these particles represent the scrapie agent must await further studies.

Animals↗
PubMed1978

Central nervous system susceptibility to herpes simplex infection.

Four days after inoculation of herpes simplex virus (HSV) on the rabbit cornea, distinctive and reproducible lesions appear in the trigeminal root entry zone. These viral lesions, situated in the central nervous system (CNS) portion of the root, consist of severe myelin destruction accompanied by mononuclear cell infiltration and partial sparing of axons. Immunofluorescent study demonstrated abundant viral antigen, and by electron microscopy viral nucleocapsids were found to be numerous within astrocytes and were rarely found in other cell types. In contrast, the adjacent peripheral nervous system (PNS) tissue appears unaffected by the presence of virus. The mechanism for this marked difference in response of the central nervous system and the peripheral nervous system may depend upon the susceptibility of astrocytes to viral infection and replication. The selective nature of the lesion provides an easily reproducible model for further investigation of the response of nervous system tissue to HSV.

Animals↗
PubMed1977

Subacute measles encephalitis complicating Hodgkin's disease in an adult.

A progressive neurological illness characterized by myoclonus, motor and sensory deficits, and lethargy occurred in a patient with Hodgkin's disease and was fatal within two months. A focal inclusion cell encephalitis was demonstrated by immunohistological means to be due to measles virus. Measles encephalitis must be considered a potential opportunistic agent in the immune-compromised host.

Antibodies, Viral↗
PubMed1976

Experimental herpes simplex virus encephalitis. Effect of corticosteroids and pyrimidine nucleoside.

The effects of methylprednisolone sodium succinate and cytarabine have been examined in an experimental herpes simplex virus-induced encephalitis in rabbits. In this model herpes simplex virus (HSV) is normally cleared from the brains of untreated animals. Infected animals treated with large doses of methylprednisolone showed a slight delay in the rate of clearance of virus, and a minimal reduction in the inflammatory process, but did not otherwise differ from untreated controls. Animals treated with cytarabine displayed a notable rise in viral titers in brain at a time when virus had been cleared from untreated controls. Cytarabine-treated animals also showed persistence of intranuclear inclusions in the lesions, and moderate diminution in the extent of inflammatory response. Thus, while methylprednisolone appears to have little adverse effect on the encephalitic process, cytarabine, perhaps because of its immunosuppressive properties, results in a failure of normal clearance of virus from nervous system lesions.

Animals↗
PubMed1976

The neuropathology of progressive rubella panencephalitis of late onset.

The clinicopathological changes in a case of progressive rubella panencephalitis of late onset have been presented. The prominent pathological findings in the brain included diffuse destruction of white matter with perivascular inflammatory cells and gliosis, moderate neuronal loss, numerous amorphous vascular deposits in the white matter and severe generalized cerebellar atrophy. These changes are compared and contrasted with those found in congenital rubella and other latent viral illnesses.

Adult↗
PubMed1976

Persistence of neuroadapted mumps virus in brains of newborn hamsters after intraperitoneal inoculation.

Neuroadapted mumps virus produces systemic infection in newborn hamsters after intraperitoneal inoculation. Virus is disseminated via a low-level viremia and appears to enter the central nervous system by passage through the choroid plexus. At such sites, choroidal and ependymal epithelial cells are productively infected and become a source for further viral spread throughout the brain parenchyma. The development of neutralizing and hemagglutination-inhibiting antibodies in serum correlates with the clearance of virus from most systemic sites. However, peristence of virus in both brain and kidney is demonstrated late in this infection.

Animals↗
PubMed1976

Ultrastructure of mumps virus replication in organotypic cultures of hamster choroid plexus.

Organotypic cultures of newborn hamster choroid plexus were inoculated with equal titre doses of newly isolated or hamster adapted strains of mumps virus. The ultrastructure of virus replication in choroid epithelial cells of the cultures was compared. No qualitative differences were observed; however, the adapted strain produced significantly greater numbers of virions and earlier destruction of the cultures. These findings are consistent with previous in vivo observations of the ultrastructure of the replication of these strains in the newborn hamster central nervous system. This in vitro study leads further support to the hypothesis that differences in the in vivo biological effects of the virus strains are primarily the result of virus-cell rather than virus-host interactions.

Animals↗
PubMed1975

Progressive rubella panencephalitis. Late onset after congenital rubella.

In children with congenital rubella infection the deficits remain stable; neurologic deterioration after the first few years of life is not believed to occur. We have encountered three patients with a definite or presumptive diagnosis of congenital rubella, in whom a progressive neurologic illness developed that began in the second decade and was characterized by spasticity, ataxia, intellectual deterioration, and seizures. High antibody titers to rubella virus in serum and spinal fluid were present in two, and all had increased cerebrospinal-fluid protein and gamma globulin. Extensive attempts to recover a virus from brain and body fluids were unsuccessful. The brains of two patients showed a widespread, progressive, subacute panencephalitis mainly affecting white matter. These data suggest that rubella virus may be a cause of progressive panencephalitis.

Adolescent↗
PubMed1975

Acquired toxoplasmosis. A neglected cause of treatable nervous system disease.

The neurological manifestations of six cases of acquired central nervous system toxoplasmosis are compared with the 39 well-documented cases from the literature. Half of the patients had underlying systemic diseases (18 malignant neoplasms, two renal transplants, three collagen vascular diseases) treated with intensive immunosuppressive therapy. The remainder had primary toxoplasmosis. Three major neurological patterns were seen: (1) diffuse encephalopathy with or without seizures, (2) meningoencephalitis, and (3) singular or multiple progressive mass lesions. Routine neurological diagnostic studies were not helpful. The Sabin-Feldman dye test or IgM indirect fluorescent antibody test or both were effective in confirming the diagnosis. Twenty-seven patients died without a clinical diagnosis of toxoplasmosis. The diagnosis was made terminally in four additional patients. Thirteen of fourteen patients who received a full course of sulfadiazine or pyrimethamine or both did well. Toxoplasmosis should be considered in the immunosuppressed patient who appears with neurological involvement.

Adult↗