Purification of non-infectious ganglioside preparations from scrapie-infected brain tissue

The extraction and purification of gangliosides from brains of animals infected with the scrapie agent was evaluated by scaling-down a large-scale procedure currently used with bovine brains. Inactivation experiments employed hamster brains infected with the 263 K strain of scrapie. Residual infectivity was determined at different points of the procedure and in the final preparation by an in vivo animal bioassay. The efficacy of single steps, which included chemicals or physical techniques known to affect the viability of the scrapie agent, was verified by spiking experiments where known amounts of infectivity were added just before each single step. Infectivity was significantly diminished at early stages of the purification, and no infectivity was detected in the final preparation containing purified gangliosides. The significant reduction of infectivity at intermediate steps and the total absence of detectable infectivity in the final product confirmed that a combination of heat and exposure to sodium hydroxide, even in the presence of organic solvents, completely inactivated the scrapie agent.

Molecular hybridization studies with scrapie brain nucleic acids. II. Differential expression in scrapie hamster brain

RNA and DNA fractions prepared from nucleic acids obtained from normal and scrapie-infected hamster brains following exhaustive treatment with nuclease were used as probes in a search for a specific scrapie nucleic acid. Employing RNA blot hybridization a 2.3 Kb RNA was detected in higher concentration in scrapie-infected hamster brains than in normal controls. Our data suggests that scrapie disease may be associated with the differential expression of a series of host genes.

Serotoninergic system in scrapie-infected hamsters

Hamsters inoculated with scrapie virus show a dramatic hypersensitivity to serotoninergic drugs, developing a behavioral syndrome not unlike that obtained with pharmacologically induced lesions of the raphe nuclei. In an attempt to explain the state of hypersensitivity and to determine whether or not serotoninergic neurons were targets of the scrapie virus, pre- and postsynaptic serotoninergic sites were studied in the cerebral cortices of scrapie-infected and sham-inoculated hamsters. [3H]Imipramine binding and the uptake of endogenous 5-hydroxytryptamine (5-HT, serotonin) in synaptosomes prepared from scrapie-inoculated animals were not different from those of controls. This suggests integrity of the serotoninergic neurons in scrapie-infected hamsters. In contrast, affinity for the 5-HT1 receptor (which modulates inhibitory response) was diminished whereas that for the 5-HT2 receptor (which modulates excitatory response) was increased. This "imbalance" between the two receptors which is amplified in in vivo responses may account for the 5-HT hypersensitivity. The alteration in the affinity of the two postsynaptic 5-HT receptors supports the observation that scrapie virus alters cell plasma membranes.

Immune function among normal Guamanians of different age

To determine if immune function differed in normal Guamanian Chamorros at various ages we measured the percentage and total numbers of lymphocytes and T-lymphocytes, their response to phytohemagglutinin (PHA), and serum levels of immunoglobulin A, G, and M in subjects 20 to 83 years of age. Regression analysis showed highly significant negative correlations for total lymphocytes and T-cells with age and a less significant negative correlation for PHA response with age in this population. Serum IgA levels increased with age, IgM levels declined, and IgG levels were unchanged. These findings are similar to, but less marked than, immunologic aberrations previously observed in Guamanians with amyotrophic lateral sclerosis or Parkinsonism-dementia. The occurrence of prominent differences in immune functions between younger and older individuals in a population where neurofibrillary degeneration in brain occurs at an early age and neurodegenerative and other age-related diseases are highly prevalent suggests the possibility that immunity and age-associated degenerative disease may be linked etiologically in this population.

Spontaneous healing of osteitis fibrosa cystica in primary hyperparathyroidism

A 24-year-old man with primary hyperparathyroidism and osteitis fibrosa cystica developed acute hypocalcaemia. Spontaneous healing of his bone disease was confirmed radiographically and by correction of the serum alkaline phosphatase. Hypercalcaemia associated with a raised serum parathyroid hormone recurred 90 weeks after the initial presentation. During the fourth neck exploration a parathyroid adenoma was removed, resulting in resolution of his condition. Haemorrhagic infarction of an adenoma was the most likely cause of the acute hypocalcaemic episode.

Antibodies in urine of chimpanzees with chronic adenoviral viruria

Many chimpanzees have naturally occurring chronic intermittent viruria with an adenovirus of a new type called Pan 11. Small amounts of neutralizing antibodies to Pan 11 adenovirus were found in the urine of chimpanzees. Urinary antibodies to adenovirus were mainly of the immunoglobulin G (IgG) class with some IgA antibodies also present. There was no neutralizing activity in urine against another adenovirus, Pan 9, which has been isolated from lymph nodes, but not from urine, of chimpanzees; however, sera of all chimpanzees had neutralizing antibodies to Pan 9 virus, some with titers similar to those of antibodies against Pan 11 virus. Antibodies reacting with simian cytomegalovirus by indirect immunofluorescence were found in sera of all chimpanzees tested and in two of six urines. There was no correlation between levels of antiviral IgG antibodies in serum and urine by immunofluorescence. These findings suggest that both IgG and IgA antibodies may be locally produced in response to viral infection of the urinary tract in primates.

Immuno-electron microscopy reveals that the excitotoxin quinolinate is associated with the plasma membrane in human peripheral blood monocytes/macrophages

Quinolinate (QUIN), a tryptophan-derived excitotoxin, was localized ultrastructurally in human peripheral blood monocytes/macrophages (MO) by immuno-electron microscopy. A combined carbodiimide/glutaraldehyde/paraformaldehyde-based fixation procedure was developed for optimal retention of QUIN in the cell as well as minimal loss of ultrastructure; a silver-enhanced colloidal gold detection system was used for electron-microscopic analysis. Gold particles representing QUIN immunoreactivity were associated with the inner side of the plasma membrane in normal MO. The number of gold particles increased significantly when QUIN levels were elevated by treatment with its precursor kynurenine, but location of the gold particles remained essentially the same under this condition. Treatment with interferon-gamma increased the number of Golgi bodies, vacuoles and pseudopodia, reflecting the activated state of the cell. Significantly increased numbers of gold particles representing QUIN were detectable in approximately the same location as in the case of kynurenine treatment. Combined treatment with kynurenine and interferon-gamma maximally increased the number of gold particles at the periphery of the cell. The pseudopodia were intensely stained with gold particles, while they were not detectable in the inner part of the cytoplasm or in any other organelle even under this activated condition. The significance of the specific location of QUIN revealed in the present study and its relation to the release and subsequent actions of QUIN are discussed.

The nucleus basalis of Meynert in parkinsonism-dementia of Guam: a morphometric study

The nucleus basalis of Meynert (nbM) was studied morphometrically in three Guamanians with parkinsonism-dementia (PD) and in two Guamanian and two non-Guamanian controls. Paraffin-embedded blocks of the nbM were serially sectioned (20 microns thick) at increments of 200 microns so that a total of 24 sections (eight each from the anterior, intermediate and posterior sectors of the nbM) were studied. The mean cell density was determined for each sector and the diameter of 50 neurons, randomly chosen in the region of apparent maximal density, was calculated. A decrease of the mean cell density, due to the loss of neurons with diameters larger than 20 microns, was found in the PD cases compared to the controls. Two PD patients exhibited striking neuronal loss (65-95%) with predominant involvement of the intermediate and posterior sectors, while the third case showed only minimal neuronal loss in these sectors (15-40%). In both Guamanian and non-Guamanian controls large neurons (diameters greater than or equal to 20 microns) exceeded small neurons while the reverse was true in all sectors of the nbM for the PD cases. These data, while confirming a previous study reporting neuronal loss in the nbM of PD patients, underline the importance of detailed morphometric analysis of the different sectors of the nbM to recognize those patients in whom lesions are not uniformly distributed.

Persistent shedding of adenovirus in urine of chimpanzees

A new adenovirus, designated Pan 11, was isolated repeatedly from the urine of several chimpanzees for more than 1 year. One chimpanzee had chronic interstitial nephritis; the others were healthy. Most chimpanzees tested had neutralizing antibodies to Pan 11 virus in the serum; three people who worked with chimpanzees also acquired antibodies. Transplantable rhabdomyosarcomas developed in hamsters inoculated as newborns with Pan 11 virus.

Mechanism of the damage to myelinated axons in experimental Creutzfeldt-Jakob disease in mice: an ultrastructural study

We report the ultrastructural pathology of myelinated axons in mice infected experimentally with the Fujisaki strain of Creutzfeldt-Jakob disease (CJD). Initially the myelin sheath was separated into several concentric bands, and cellular processes penetrated between layers of myelin and lifted away the outermost lamella. Then a complicated labyrinth of the concentric cellular processes, clearly belonging to either astrocytes or macrophages, invested myelinated axons. In terminal stages axons completely denuded of myelin were seen in the center of concentric networks of cellular processes. Myelin remnants were seen within astrocytes and macrophages. We conclude that the mechanism(s) of damage to myelinated axons in CJD may be similar to that operating in immunologically mediated demyelinating disorders.

Ultrastructural pathology of a Chilean case of tropical spastic paraparesis/human T-cell lymphotropic type I-associated myelopathy (TSP/HAM)

Human T-cell lymphotropic virus type I (HTLV-I), is the cause of endemic tropical spastic paraparesis (TSP) or HTLV-I-associated myelopathy (HAM). Because TSP/HAM is not a fatal disease, the neuropathology of this disease, albeit relatively well understood, is based on the examination of just a few incidental cases. Previously, we demonstrated peculiar lamellated structures, called "multilamellar bodies" (MLB). In this report, we present the ultrastructural neuropathology of a TSP/HAM case from Chile, with further detailed descriptions of MLB. It is tempting to suggest that MLB may represent specific ultrastructural markers of TSP/HAM. The pathology of the anterior and posterior horns was similar and was comprised of axonal degeneration, accompanied by extensive astrocytic gliosis. Lymphocytic infiltration, particularly observed as "cuffs" around blood vessels, was scattered among other cellular elements. Ultrastructurally, myelin sheaths were relatively well preserved, and some demyelinated but not remyelinated fibers were observed. Moreover, axons with abnormal accumulations of neurofilaments, suggestive of axonal degeneration, were detected. Several axons contained Hirano bodies. In many samples, glial processes replaced most of the remaining neuropil. In a few specimens of the anterior and posterior horns of the spinal cord, MLB were observed. These structures consisted of stacks of 30 to 40 electron-dense lamellae, which were interrupted by narrow electron-lucent spaces. All of the lamellae were immersed within an amorphous substance of intermediate density. Neurons of the dorsal root ganglia were basically normal except for increased lipofuscin accumulation. As in the spinal cord, myelinated axons were well preserved, but a few were demyelinated and surrounded by concentric arrays of Schwann cell membranes. Also, axons of the dorsal roots accumulated increased number of neurofilaments. Mast cells and Schwann cells were increased in number, the latter containing abundant pi granules and myelin fragments.

Induction in chimpanzees of antibodies inhibiting receptor-mediated cell fusion by HIV glycoprotein

Cell fusion of HTLV-IIIB-infected EBV-transformed B cells and CD4+ T cells was inhibited by sera from eight of nine HIV infected chimpanzees. Syncytia formation was reduced by sixty percent relative to control after only 5 minutes of preincubation of the HIV infected cells with immune primate serum, indicating that these antibodies have high affinity for HIV protein on the surface of infected cells. Serum dilutions that blocked formation of syncytia irreversibly within 24 hrs also blocked expression of HIV antigens by the target CD4+ cells. Three of four animals inoculated with the LAV or HTLV-IIIB strain of HIV developed antibodies inhibiting CD4-dependent cell fusion by HIV glycoprotein (CFI-antibodies) 2-3 months after inoculation coincident with development of HIV specific IgG antibodies. Similar early CFI-antibody responses occurred in two second passage chimpanzees. In contrast, a chimpanzee infected with a third passage of LAV had a delayed CFI-antibody response, indicating that variants of HIV with divergent CFI epitopes did eventually emerge. Delayed development of CFI-antibodies (6-11 months after inoculation) relative to HIV specific IgG ELISA antibody was also seen in a chimpanzee on primary passage and a chimpanzee on second passage of HTLV-IIIB. No CFI-antibodies were detected in a chimpanzee following inoculation with human brain tissue, while antibodies to other structural proteins were recognized by immunoblotting. These results indicate that changes in CFI epitopes occur under immune pressure and that the appearance of CFI-antibodies depends on the time after infection and on the degree to which CFI epitopes of the inoculum strain diverge from those of the test strain.

Transmission of Creutzfeldt-Jakob disease to the patas monkey (Erythrocebus patas) with cytopathological changes in in vitro cultivated brain cells

The transmission of Creutzfeldt-Jakob disease (CJD) to the patas monkey, Erythrocebus patas, has been accomplished. Clinical neurological disease was first noticed 47 months and 23 days after intracerebral inoculation of infected squirrel monkey brain. The disease progressed slowly and lasted 8 months. Microscopic examination of the brain and spinal cord revealed lesions of status spongiosus and astrogliosis in the cortical gray matter consistent with a diagnosis of experimental CJD. A vacuolating 'spongiform' cytopathological effect was seen in many of the in vitro cultivated brain cells in the outgrowth from explanted brain tissue of this monkey.

Ganglioside composition changes in spongiform encephalopathies: analyses of 263K scrapie-infected hamster brains

Ganglioside composition in brains of terminally ill LVG/LAK golden Syrian hamsters infected with the 263K strain of the scrapie agent was analyzed. Results were compared to those obtained from noninfected animals matched by age, sex, and strain. Gangliosides extracted from scrapie-infected animals showed little change in major components, while an increased number of new alkali-labile species appeared. Additionally, the animal strain employed demonstrated a significant polymorphism in brain ganglioside composition. No significant changes in incubation time, clinical development or pathologic features of scrapie were associated with this polymorphism.

HLA-DR expression in macaque neuroendothelial cells in vitro and during SIV encephalitis

HLA-DR expression in neuroendothelial cells (NEC) was studied during the course of SIV encephalitis in rhesus monkeys. HLA-DR determinants were detected on NEC in monkeys with SIV encephalitis, but not in control animals. In situ hybridization with an SIV probe indicated that HLA-DR expression was not a consequence of SIV replication within NEC. Cultured rhesus NEC stimulated with gamma interferon expressed HLA-DR to a higher degree than cultured brain fibroblasts or astrocytes. These data support the contention that NEC participate in retrovirus-induced inflammation and autoimmunity within the central nervous system.

Isolation and characterization of two new herpes-like viruses from capuchin monkeys

Two herpes-like viruses were isolated from capuchin monkey (Cebus apella) brain and (Cebus albifrons) spleen cell cultures, respectively. Both isolates induced similar cytopathic effects consisting of rounded and ballooned cells in the original monkey cell cultures and in a wide range of permissive cell types. Neutralizing antibody to each virus was present in serum from the capuchin monkey from which it was isolated, but the two viruses did not cross-react by neutralization. Fluorescein isothiocyanate conjugates of hyperimmune rabbit serum to one of the isolates showed an antigenic cross relationship between the two isolates. By electron microscopy, herpes-like virus particles were observed in the nucleus and cytoplasm of infected human diploid fibroblast cell cultures. Virus-infected cell cultures stained with acridine orange revealed small deoxyribonucleic acid-containing intranuclear inclusion bodies. Both viruses were inhibited by 5-fluorodeoxyuridine and inactivated by chloroform or exposure to 56 degrees C for 30 min. Antisera prepared against 16 prototype herpesviruses and cytomegaloviruses did not neutralize approximately 100 50% tissue culture infective doses of either capuchin isolate. Neutralizing antibody to the capuchin isolates was detected in sera from 8 of 17 capuchin monkeys but not in sera from 16 humans, 15 chimpanzees, and 10 spider, 6 rhesus, and 5 squirrel monkeys.

Transmission of human T-cell leukemia virus type I from a patient with HTLV-I associated myelopathy/tropical spastic paraparesis and an asymptomatic carrier to rabbits

Rabbits were infected successfully with two strains of human T-cell leukemia virus type I (HTLV-I), one isolated from a Colombian patient with HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) and the other from an asymptomatic carrier. HTLV-I was repeatedly demonstrated in peripheral blood mononuclear cells (PBMNC) of infected rabbits, and the rabbits had elevated antibodies against the various structural proteins of HTLV-I. Four rabbits inoculated with HTLV-I-infected autologous lymphoid cells intravenously (i.v.) and intracerebrally (i.c.) had virus present in their PBMNC for more than 40 weeks, while those that were inoculated either with HTLV-I-infected human lymphoid cells or with autologous rabbit lymphoid cells intraperitoneally (i.p.) had episodes during which virus was not recovered from their PBMNC. The one rabbit inoculated i.p. developed antibodies to viral envelope glycoproteins earlier than did those inoculated i.v. and i.c. Rabbit lymphoid cell lines persistently infected with HTLV-I were established by cocultivating the rabbit PBMNC with HTLV-I-infected human lymphoid cells that had been irradiated or by inoculation with cell-free supernatant fluids of HTLV-I infected non-irradiated lymphoid cell cultures. HTLV-I-infected rabbit cell lines were of T-cell origin and expressed HTLV-I antigens by immunofluorescence. Electron microscopy revealed type-C retrovirus particles.

Failure to detect scrapie virus in sheep at slaughter in a highly endemic region of France

A study was carried out in a sheep slaughterhouse located in a region of France where scrapie has been endemic for several decades. Neuropathological examination of 63 randomly selected lambs and adult sheep revealed no scrapie-related abnormalities, and inoculation of mice with brain, tonsil, lateropharyngeal ganglia, and intestine from the same animals did not transmit scrapie. The failure to detect any evidence of scrapie infection in commercially-bred sheep, the absence of an increased mortality rate for human CJD in the surrounding consumer region, and the absence of a single case of CJD among slaughterhouse personnel, do not support the hypothesis that exposure to potentially scrapie-contaminated products is responsible for CJD in humans.