Tropical spastic paraparesis

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. We summarise our experience with the neuropathology of tropical spastic paraparesis/HTLV-I associated myelopathy (TSP/HAM). We studied three cases of TSP/HAM from different parts of the world. We demonstrated peculiar lamellated structures, called "multilamellar bodies" (MLB). It is tempting to suggest that MLB may represent specific ultrastructural markers of TSP/HAM. The pathology of the anteriorand posterior horns was similar and comprised 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 fibres 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.

Immunophenotyping of peripheral blood, ranges of serum chemistries and clinical hematology values of healthy chimpanzees (Pan troglodytes)

This paper presents clinical chemistry, hematology and immunophenotyping data from 102 chimpanzees over a 2-year period. The groupings were: 3 years or less, 4-7 years, and 8 + years. These data are intended to augment formerly published information on these parameters and to serve as a concise reference guide for primate veterinarians and researchers for whom these data may be useful. This study has larger samplings than previously published data and more panel constituents by immunophenotyping.

An enzyme-linked immunosorbent assay to quantify 14-3-3 proteins in the cerebrospinal fluid of suspected Creutzfeldt-Jakob disease patients

The detection of 14-3-3 protein by Western immunoblot is a sensitive and specific cerebrospinal fluid marker of Creutzfeldt-Jakob disease (CJD). We developed a quantitative enzyme-linked immunosorbent assay (ELISA) that reliably detects 14-3-3 in cerebrospinal fluid. In a prospective study of 147 cerebrospinal fluid samples, the mean 14-3-3 concentration among pathologically confirmed CJD patients (28.0+/-20.6 ng/ml, n = 41) is significantly higher than the mean in the cerebrospinal fluid of those with other neurological disorders (3.1+/-2.9 ng/ ml, n = 84). At a cutoff value of 8.3 ng/ml, the ELISA has a sensitivity of 92.7% and a specificity of 97.6%. The 14-3-3 ELISA supports a diagnosis of CJD in patients who fulfill clinical criteria for possible CJD.

New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication

One-gram samples from a pool of crude brain tissue from hamsters infected with the 263K strain of hamster-adapted scrapie agent were placed in covered quartz-glass crucibles and exposed for either 5 or 15 min to dry heat at temperatures ranging from 150°C to 1,000°C. Residual infectivity in the treated samples was assayed by the intracerebral inoculation of dilution series into healthy weanling hamsters, which were observed for 10 months; disease transmissions were verified by Western blot testing for proteinase-resistant protein in brains from clinically positive hamsters. Unheated control tissue contained 9.9 log 10 LD 50 /g tissue; after exposure to 150°C, titers equaled or exceeded 6 log 10 LD 50 /g, and after exposure to 300°C, titers equaled or exceeded 4 log 10 LD 50 /g. Exposure to 600°C completely ashed the brain samples, which, when reconstituted with saline to their original weights, transmitted disease to 5 of 35 inoculated hamsters. No transmissions occurred after exposure to 1,000°C. These results suggest that an inorganic molecular template with a decomposition point near 600°C is capable of nucleating the biological replication of the scrapie agent.

Novel PRNP sequence variant associated with familial encephalopathy

Human transmissible spongiform encephalopathies (TSEs) are a group of chronic progressive neurodegenerative disorders that may be hereditary, infectious, or sporadic. Hereditary TSEs are associated with mutations in the PRNP gene on chromosome 20p12-pter. We report on a family in which seven patients developed limb and truncal ataxia, dysarthria, myoclonic jerks, and cognitive decline. The age of onset in the 30s, 40s, or 50s, prolonged disease duration, cerebellar atrophy on imaging, and the presence of synchronic periodic discharges on electroencephalogram suggested a familial encephalopathy resembling Gerstmann-Sträussler-Scheinker disease. A novel H187R mutation has been identified in affected, but not in unaffected, family members or unrelated controls suggesting a pathogenic role for this mutation. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:653-656, 1999. Published 1999 Wiley-Liss, Inc.

Increased levels of epsilon and gamma isoforms of 14-3-3 proteins in cerebrospinal fluid in patients with Creutzfeldt-Jakob disease

We established four hybridoma cell lines producing monoclonal antibodies (MAbs) against 14-3-3 proteins. Immunoblot analysis revealed that epsilon and gamma isoforms were specifically increased in premortem cerebrospinal fluid samples from patients with sporadic Creutzfeldt-Jakob disease. Furthermore, dot immunoblot analysis showed that MAbs were more specific for native antigen than polyclonal antibodies were.

Creutzfeldt-Jakob disease diagnosable by EEG and cerebrospinal fluid analysis without brain biopsy: a case report

This case illustrates a classic example of CJD in its clinical presentation and course and the EEG. It also shows dramatically the utility of a newly developed protein assay in the diagnosis of this disease. This assay has the potential of eliminating the need for brain biopsy in most cases, thus providing a safer diagnostic method for both staff and patients. In addition, the case points out that anatomical structural studies such as CT and MRI do not replace the utility of EEG in the comprehensive evaluation of rapid onset dementia, but rather complement the usefulness of EEG.

Evidence for widespread infection of wild rats with hepatitis E virus in the United States

Hepatitis E is an important medical pathogen in many developing countries but is rarely reported from the United States, although antibody to hepatitis E virus (anti-HEV) is found in > 1% of U.S. citizens. Zoonotic spread of the virus is suspected. Sera obtained from 239 wild rats trapped in widely separated regions of the United States were tested for anti-HEV. Seventy-seven percent of rats from Maryland, 90% from Hawaii, and 44% from Louisiana were seropositive for anti-HEV. Rats from urban as well as rural areas were seropositive and the prevalence of anti-HEV IgG increased in parallel with the estimated age of the rats, leading to speculation that they might be involved in the puzzling high prevalence of anti-HEV among some U.S. city dwellers. The discovery of a in rats in the United States and the recently reported discovery that HEV is endemic in U.S. swine raise many questions about transmission, reservoirs, and strains of HEV in developed countries.

Early induction of protein nexin-I in scrapie

We used RNA fingerprinting by arbitrary primed PCR to identify genes whose expression is up-regulated in the brain of hamsters affected by prion disease. One gene implicated by RNA fingerprinting encoded the hamster homologue of protein nexin-I (PN-I), a serine proteinase inhibitor, and was further investigated by Northern blot analysis. PN-I mRNA levels were increased at pre-clinical stages (19 days after inoculation) and remained elevated when the spongiform encephalopathy was anatomopathologically and clinically evident (at 50 and 80 days). Future RNA screening conducted as illustrated may help to reveal a spectrum of genes relevant for the etiopathogenesis and/or diagnosis of prion disease.

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.

Phenotypic variability of Gerstmann-Sträussler-Scheinker disease is associated with prion protein heterogeneity

Gerstmann-Sträussler-Scheinker disease (GSS), a cerebello-pyramidal syndrome associated with dementia and caused by mutations in the prion protein gene (PRNP), is phenotypically heterogeneous. The molecular mechanisms responsible for such heterogeneity are unknown. Since we hypothesize that prion protein (PrP) heterogeneity may be associated with clinico-pathologic heterogeneity, the aim of this study was to analyze PrP in several GSS variants. Among the pathologic phenotypes of GSS, we recognize those without and with marked spongiform degeneration. In the latter (i.e. a subset of GSS P102L patients) we observed 3 major proteinase-K resistant PrP (PrPres) isoforms of ca. 21-30 kDa, similar to those seen in Creutzfeldt-Jakob disease. In contrast, the 21-30 kDa isoforms were not prominent in GSS variants without spongiform changes, including GSS A117V, GSS D202N, GSS Q212P, GSS Q217R, and 2 cases of GSS P102L. This suggests that spongiform changes in GSS are related to the presence of high levels of these distinct 21-30 kDa isoforms. Variable amounts of smaller, distinct PrPres isoforms of ca. 7-15 kDa were seen in all GSS variants. This suggests that GSS is characterized by the presence PrP isoforms that can be partially cleaved to low molecular weight PrPres peptides.

Adenovirus-mediated human immunodeficiency virus-1 Nef expression in human monocytes/macrophages and effect of Nef on downmodulation of Fcgamma receptors and expression of monokines

To characterize the effect of human immunodeficiency virus-1 (HIV-1) nef expression in human monocytes/macrophage (HMO) and U937 on the levels of FcgammaRs, HLA antigens, and monokines, elutriated HMOs and U937 cells were transfected with an adenovirus-mediated Nef expression system. Nef-expressing cells downmodulated FcgammaRI, FcgammaRII, and upregulated HLA class I molecules. Nef-expressing HMOs, treated with lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA), overexpressed tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-10. However, IL-6 was induced by LPS and inhibited by PMA. Additionally, a subpopulation of Nef-expressing HMOs underwent apoptosis. Our data suggest that HIV-1 nef downmodulated FcgammaRs in myeloid cells in a manner similar to that previously reported for its effect on CD4+ in T cells.

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.

Phylogenetic analysis of simian T-lymphotropic virus Type I (STLV-I) in common chimpanzees (Pan troglodytes): evidence for interspecies transmission of the virus between chimpanzees and humans in Central Africa

Serum and peripheral blood leukocytes from the chimpanzees (Pan troglodytes) of the colony of the Laboratory of Central Nervous System Studies, National Institute of Neurological Disorders and Stroke, NIH, were tested for the presence of STLV-I-specific antibodies and proviral DNA. Antibodies were determined by gelatin particle agglutination and Western blot (WB) assays utilizing HTLV-I antigens. Proviral DNA was detected by four PCR assays targeting three different regions of STLV-I genome: the fragments of the env and pol genes and LTR. Twenty of twenty-two DNA samples from WB-positive animals were PCR positive. None of the DNA samples from WB-negative (n = 5) and WB-indeterminate (n = 4) animals was PCR positive. The results of the nested and double nested env PCR tests were fully concordant; the seminested LTR PCR test was much less sensitive. The DNA sequences from the env (483 bp) and the pol (200 bp) genes and LTR (705 bp) were determined for six, two, and two chimpanzee STLV-I isolates, respectively. Phylogenetic analysis revealed that chimpanzee STLV-I isolates can be attributed to three clades. The first of these clades (SS-PTR1/CSA) included STLV-I isolates from the chimpanzees and West African subspecies of African green monkeys (Cercopithecus a. sabaeus). The other clades (S-PTR2 and S-PTR3) included STLV-I isolates only from chimpanzees. However, both S-PTR2 and S-PTR3 clustered together with Central African HTLV-I comprising the human/simian clade (HS-HSA/PTR). This pattern of phylogenetic clustering suggests that interspecies transmission of STLV-I occurred between chimpanzees and African green monkey subspecies as well between chimpanzees and human populations in Central Africa.

Normal isoform of amyloid protein (PrP) in brains of spawning salmon

The transmissible spongiform encephalopathies are a group of subacute progressive degenerative diseases of the nervous system which are always fatal in their outcome. These diseases appear to be caused by the abnormal isoform of the precursor protein of amyloid designated prion protein. The normal isoform has been identified in the tissues of all mammalian species thus far tested as well as in Drosophila. We report the presence of this protein for the first time in the brains of fish.

Myelopathy among Brazilians coinfected with human T-cell lymphotropic virus type I and HIV

OBJECTIVE

To determine whether subjects coinfected with HTLV-I and HIV have a higher frequency of myelopathy than subjects singly infected with HIV.

DESIGN

A prospective, nested case-control study of HTLV-I and HIV coinfected (cases) and HIV singly infected adults (controls) participating in a prospective HIV cohort study at a university hospital outpatient HIV clinic in Rio de Janeiro, Brazil.

MEASUREMENTS

Subjects were evaluated for evidence of myelopathy by a neurologist unaware of their HTLV serologic status. Patients with at least two pyramidal signs, such as paresis, hypertonicity or spasticity, hyperreflexia, clonus, diminished or absent superficial reflexes, or the presence of pathologic reflexes (e.g., Babinski or Hoffmann), were defined as having myelopathy. Myelopathy severity was quantified using the Kurtzke Functional Disability Scale (FDS); patients with FDS scores > or = 4 were considered to have significant myelopathy. Selected patients with myelopathy underwent lumbar puncture for the evaluation of intrathecal synthesis of HTLV-I antibodies.

RESULTS

Of 15 coinfected subjects, 11 (73%) had evidence of myelopathy versus 10 of 62 subjects (16%) with HIV single infection (adjusted odds ratio [OR] = 13.0, p = 0.00002). When only myelopathy patients with FDS scores of > or = 2 or > or = 4 were included, the association between coinfection and the presence of myelopathy remained (OR = 7.3, p = 0.0003 for scores > or = 2; and OR = 8.9 for scores > or = 4, p = 0.04). In addition, a higher proportion of coinfected subjects had peripheral neuropathy (40%) than controls (16%) (OR = 3.5, p = 0.07).

CONCLUSION

Coinfection with HTLV-I was strongly associated with myelopathy among subjects infected with HIV. The relative contribution of HTLV-I versus HIV in the pathogenesis of coinfection-associated myelopathy is not known. Coinfection may also be associated with peripheral neuropathy. Further studies are needed to elucidate the mechanisms of coinfection-associated neurologic conditions.

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.

Increased quinolinate immunoreactivity in the peripheral blood monocytes/macrophages from SIV-infected monkeys

Quinolinate (QUIN), a metabolite in the kynurenine pathway of tryptophan degradation and a neurotoxin that is thought to act through the NMDA receptor system, was localized in cultured peripheral blood monocytes/macrophages from SIV-infected monkeys using a recently developed immunohistochemical method. Significant increases in QUIN immunoreactive (IR) cells were detected in all five SIV-infected monkeys examined. Multinucleated giant cells, a hallmark of lentiviral infection, were visible in selected samples. Treatment with the QUIN precursors, tryptophan and kynurenine, increased the number of QUIN-IR cells in both the control and SIV-infected preparations, perhaps by a mass action mechanism. We hypothesize that in SIV-infected monkeys, infiltrating monocytes/macrophages contribute to the high level of brain QUIN and associated neuropathology.

The 14-3-3 brain protein in cerebrospinal fluid as a marker for transmissible spongiform encephalopathies

BACKGROUND

There is no practical and reliable premortem test for Creutzfeldt-Jakob disease and the related transmissible spongiform encephalopathies. Two proteins, designated 130 and 131, which have been detected in low concentrations in cerebrospinal fluid from patients with Creutzfeldt-Jakob disease, appear to be sensitive and specific markers for the disease. Attempts to identify these proteins, however, have been unsuccessful. We hypothesized that they may be present in the normal brain.

METHODS

We detected proteins 130 and 131 in normal human brain, partially sequenced their amino acids, and found that they matched the brain protein known as 14-3-3. We then developed a simple, rapid immunoassay for this protein and tested it in cerebrospinal fluid samples from 71 humans and 30 animals with spongiform encephalopathies and in control samples from 186 humans and 94 animals.

RESULTS

The immunoassay detected the 14-3-3 protein in cerebrospinal fluid from 68 of the 71 patients with Creutzfeldt-Jakob disease (96 percent, 95 percent confidence interval, 92 to 99 percent). Among 94 patients with other dementias, the specificity was 96 percent. If one excludes the three patients with dementia who had strokes within one month before testing, the specificity was 99 percent. The test was positive in 12 of 24 patients with viral encephalitis. In animals the sensitivity of the assay was 87 percent and the specificity was 99 percent.

CONCLUSION

In patients with dementia, a positive immunoassay for the 14-3-3 brain protein in cerebrospinal fluid strongly supports a diagnosis of Creutzfeldt-Jakob disease. This finding, however, does not support the use of the test in patients without clinically evident dementia.

Anterior horn cell degeneration in polymyositis associated with human T lymphotropic virus Type-1 in patients from Barbados

Anterior horn cell degeneration has only occasionally been noted in patients with tropical spastic paraparesis associated with human T lymphotropic virus type-1 (HTLV-1) infection. We report on three adult patients with HTLV-1-associated polymyositis who had clinical evidence of anterior horn cell degeneration. One patient had moderate proximal weakness and muscle wasting in all four limbs, while two had mild upper limb weakness with more profound proximal weakness and wasting in the lower limbs. In all three patients, electromyographic findings were compatible with motor unit loss and muscle biopsies showed mononuclear inflammatory cell infiltration; muscle biopsies in two patients showed features of denervation. Immunoglobulin G (IgG) antibodies to HTLV-1 were detected by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western immunoblot in serum and cerebrospinal fluid in all three patients. In two, cell cultures were established from peripheral blood lymphocytes and HTLV-1 antigen was identified by immunofluorescence and the ELISA antigen-capture technique using an anti-p19 HTLV-1 mouse monoclonal antibody. The three cases illustrate the variety of neuromuscular disease, other than spastic paraparesis, that may occur in HTLV-1 infection. In some cases of HTLV-1-associated polymyositis, anterior horn cell degeneration may make a significant contribution to the muscle atrophy observed.

Retroviruses and schizophrenia in Jamaica

Reports of an 18-fold higher incidence of schizophrenia among second-generation Afro-Caribbeans, and especially Jamaican migrants in the United Kingdom were soon called "an epidemic of schizophrenia," with the inference that a novel virus, likely to be perinatally transmitted, was a possible etiological agent. This intriguing observation led us to explore a possible link with human T-cell lymphotropic virus type one (HTLV-I), because it is a virus that is endemic in the Caribbean Island, is perinatally transmitted, known to be neuropathogenic, and the cause of a chronic myelopathy (tropical spastic paraparesis/HTLV-I associated myelopathy. We therefore examined inpatients as the Bellevue Mental Hospital, Kingston, Jamaica and did standard serological tests for retroviruses HTLV-I and HTLV-II and HIV-I and HIV-II on 201 inpatients who fulfilled ICD-9 and DSM III-R criteria for schizophrenia. Our results produced important negative data, since the seropositivity rates for HTLV-I, the most likely pathogen, were no greater than the seropositivity range for HTLV-I carriers in this island population, indicating the HTLV-1 and the other retroviruses tested do not play a primary etiological role in Jamaican schizophrenics.

Immunocytochemical localization of the endogenous neuroexcitotoxin quinolinate in human peripheral blood monocytes/macrophages and the effect of human T-cell lymphotropic virus type I infection

Quinolinate (Quin), a metabolite in the kynurenine pathway of tryptophan degradation and a neurotoxin that appears to act through the N-methyl-D-aspartate receptor system, was localized in cultured human peripheral blood monocytes/macrophages (PBMOs) by using a recently developed immunocytochemical method. Quin immunoreactivity (Quin-IR) was increased in gamma interferon (IFN-gamma)-stimulated monocytes/macrophages (MOs). In addition, the precursors, tryptophan and kynurenine, significantly increased Quin-IR. Infection of MOs by human T-cell lymphotropic virus type I (HTLV-I) in vitro substantially increased both the number of Quin-IR cells and the intensity of Quin-IR. At the peak of the Quin-IR response, about 40% of the cells were Quin-IR positive. In contrast, only about 2-5% of the cells were positive for HTLV-I, as detected by both immunofluorescence for the HTLV-I antigens and PCR techniques for the HTLV-I Tax gene. These results suggest that HTLV-I-induced Quin production in MOs occurs by an indirect mechanism, perhaps via cytokines produced by the infection but not directly by the virus infection per se. The significance of these findings to the neuropathology of HTLV-I infection is discussed.

Widespread, restricted low-level measles virus infection of brain in a case of subacute sclerosing panencephalitis

In situ reverse transcriptase-polymerase chain reaction amplification with labeled-probe hybridization (in situ RT-PCR/LPH) was used to detect measles virus RNA within formalin-fixed, paraffin-embedded brain tissue sections from a patient who died with subacute sclerosing panencephalitis (SSPE). Many more infected neurons and oligodendrocytes were detected by in situ RT-PCR/LPH than by immunohistochemistry or by in situ hybridization alone. In addition, infection of vascular endothelial cells was demonstrated only by in situ RT-PCR/LPH. The observation that many cells contained only a few copies of viral RNA without detectable antigen is consistent with a persistent viral infection of the central nervous system. In situ RT-PCR/LPH, combining the sensitivity of PCR with the tissue localization of in situ hybridization, should prove useful in further studies to detect nucleic acids in situ in the central nervous system.

HLA DRB1*DQB1* haplotype in HTLV-I-associated familial infective dermatitis may predict development of HTLV-I-associated myelopathy/tropical spastic paraparesis

A possible causal association between infective dermatitis and HTLV-I infection was reported in 1990 and confirmed in 1992. We now report familial infective dermatitis (ID) occurring in a 26-year-old mother and her 9-year-old son. The mother was first diagnosed with ID in 1969 at the age of 2 years in the Dermatology Unit at the University Hospital of the West Indies (U.H.W.I.) in Jamaica. The elder of her 2 sons was diagnosed with ID at the age of 3 years, also at U.H.W.I. Both mother and son are HTLV-I-seropositive. A second, younger son, currently age 2 years, is also HTLV-I-seropositive, but without clinical evidence of ID. Major histocompatibility complex (MHC), class II, human leucocyte antigen (HLA) genotyping documented a shared class II haplotype, DRB1*DQB1* (1101-0301), in the mother and her 2 sons. This same haplotype has been described among Japanese patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and has been associated with a possible pathologically heightened immune response to HTLV-I infection. The presence of this haplotype in these familial ID cases with clinical signs of HAM/TSP may have contributed to their risk for development of HAM/TSP. The unaffected, HTLV-I-seropositive younger son requires close clinical follow-up.

Western blot mapping of disease-specific amyloid in various animal species and humans with transmissible spongiform encephalopathies using a high-yield purification method

SAF-protein, an amyloid, is the main constituent of scrapie-associated fibrils (SAF) and a specific marker for transmissible spongiform encephalopathies (TSE). Using an improved extraction method and Western blot detection, the disease-specific amyloid was found in various parts of the central nervous system of hamsters orally infected with scrapie, of squirrel monkeys orally infected with kuru, sporadic Creutzfeldt-Jakob disease (CJD) and scrapie, of human patients with sporadic CJD, of a sheep with natural scrapie and of a cow with bovine spongiform encephalopathy (BSE). In human CJD samples, the concentration of TSE-specific amyloid was estimated to be 1000- to 10 000-fold lower than in the central nervous system of hamsters with scrapie. The extraction method has a yield of 70% and allows Western blot detection of the TSE-specific amyloid in samples representing 1-10 micrograms of brain tissue from intracerebrally infected hamsters, as well as in individual spleens from hamsters with terminal scrapie infected by the intracerebral, oral or intraperitoneal route. A 20-100 mg sample of material is sufficient for the extraction of the pathological protein from different rodent, monkey, ovine, bovine and human tissues. The results reported here demonstrate the potential suitability of the method for the routine diagnosis of TSE as well as for the detailed analysis of distribution patterns of the TSE-specific amyloid in experimental approaches to the investigation of these diseases.

Identification of human T cell leukemia/lymphoma virus type I antibodies, DNA, and protein in patients with polymyositis

OBJECTIVE

To investigate a possible association between human T cell leukemia/lymphoma virus type I (HTLV-I) and polymyositis (PM).

METHODS

Sera and muscle biopsy samples from 9 Jamaican PM patients were compared with specimens from American HTLV-I-positive PM patients and normal controls. Sera were evaluated for HTLV antibodies by enzyme-linked immunosorbent assay and Western blot. The biopsy samples were analyzed for HTLV-I/II DNA by polymerase chain reaction and were also immunohistochemically stained for HTLV gp46 envelope protein.

RESULTS

Seven of the 8 Jamaican PM patients from whom sera were available were HTLV-I seropositive. The muscle biopsies of all 9 Jamaican patients demonstrated severe lymphocytic infiltration, cellular degeneration, myofiber atrophy, and fibrosis. Each muscle biopsy specimen contained HTLV-I DNA. Two of 6 samples demonstrated intense staining for HTLV-I gp46 in many of the invading mononuclear cells and weak staining for HTLV-I gp46 in many of the invading mononuclear cells and weak staining in the adjacent myocytes. Two other specimens were weakly positive for gp46 in rare mononuclear cells. All control specimens were negative for the presence of HTLV-I DNA and protein.

CONCLUSION

HTLV-I is associated with an inflammatory muscle disease characterized by direct invasion of the affected muscle by HTLV-I-infected mononuclear cells.

Infectious amyloid precursor gene sequences in primates used for experimental transmission of human spongiform encephalopathy

Based on the analysis of genomic DNA from single healthy animals of each of five primate species, nucleotide and predicted amino acid sequences of the infectious amyloid precursor gene of higher apes (Gorilla and Pan) and Old World (Macaca) and New World (Ateles, Saimiri) monkeys showed 95-99% homology to the human sequences, corresponding to their phylogenetic distance from humans. Two of 18 amino acids that differed from humans resulted from nucleotide changes at sites of mutations in humans with familial forms of spongiform encephalopathy (a deleted codon within the codon 51-91 region of 24 bp repeats and a substitution at codon 198). In each of the five animals, codon 129 specified methionine, the more common of the two polymorphic genotypes in humans. Because genotypic homology did not correlate with experimental transmission rates of human spongiform encephalopathy, primary structural similarity of the infectious amyloid precursor protein in humans and experimental primates may not be an important factor in disease transmissibility.

Ultrastructural pathology of human T-cell lymphotropic virus type I encephalomyelopathy in a white patient with adult T-cell leukemia/lymphoma

A white patient with human T-cell lymphotropic virus type I (HTLV-I)-associated adult T-cell leukemia/lymphoma for 10 years died 4 months after the onset of spastic myelopathy. Ultrastructurally, the neuropathologic findings consisted of dystrophic neurites (spheroids) filled with neurofilaments or electron-dense bodies, intense astrocytic reaction with abundant formation of corpora amylacea, and multilamellar bodies. Demyelination and spongiform change were absent. Viruslike particles resembling HTLV-I were detected adjacent to brain endothelial cells.

The consistent use of organic solvents for purification of phospholipids from brain tissue effectively removes scrapie infectivity

A procedure for the purification of phospholipids from brain tissue was evaluated for its efficacy in eliminating scrapie agent infectivity. The key feature of the process was that phospholipids were extracted and purified by exclusive use of organic solvents. Experiments were done by in vivo animal bioassay on a scaled-down version of the original procedure using 263 K-infected hamster brains as source material. The absence of any detectable infectivity in the final preparations indicated that organic solvent extraction is acceptable for purification and decontamination of biological products from scrapie-like agents provided that only the organic phase is used.

Scrapie amyloid (prion) protein has the conformational characteristics of an aggregated molten globule folding intermediate

The scrapie amyloid (prion) protein (PrP27-30) is a host-derived component of the infectious scrapie agent; the potential to replicate, propagate, and form amyloid is a result of the posttranslational event or conformational abnormality. In low concentrations of guanidine hydrochloride (Gdn.HCl), PrP27-30 dissociates into a compact equilibrium intermediate with a substantial portion of secondary structure, partially denatured tertiary structure, and tryptophan residues in an apolar environment [Safar, J., Roller, P. P., Gajdusek, D. C., & Gibbs, C. J., Jr. (1993) J. Biol. Chem. 27, 20276-20284]. Here we describe the characteristics of this metastable form as monitored by 8-anilino-1-naphthalenesulfonate (ANS) fluorescence spectroscopy and circular dichroism (CD) spectroscopy, and we propose a mechanism for scrapie amyloid association. The Gdn.HCl-induced equilibrium intermediate of PrP27-30 had multiple high-affinity hydrophobic binding sites for ANS, some close to the Trp residues. The amide CD spectrum of an acid-induced intermediate (A-form), in equilibrium at pH < 2.0, was similar to the Gdn.HCl-induced intermediate and suggested the presence of a significant portion of an alpha-helical or beta-turn secondary structure. In contrast, the PrP27-30 associated into aggregates in an all beta-sheet conformation with less ordered and more exposed hydrophobic side chains. The noncooperative unfolding of the Gdn.HCl-induced intermediate at high temperature was irreversible and correlated with the loss of infectivity. The results demonstrate that PrP27-30 associates through a compact, metastable hydrophobic intermediate with an nonnative, nondenatured secondary structure and a tertiary structure close to the unfolded form.(ABSTRACT TRUNCATED AT 250 WORDS)

Transmission of Creutzfeldt-Jakob disease to a chimpanzee by electrodes contaminated during neurosurgery

Stereotactic multicontact electrodes used to probe the cerebral cortex of a middle aged woman with progressive dementia were previously implicated in the accidental transmission of Creutzfeldt-Jakob disease (CJD) to two younger patients. The diagnoses of CJD have been confirmed for all three cases. More than two years after their last use in humans, after three cleanings and repeated sterilisation in ethanol and formaldehyde vapour, the electrodes were implanted in the cortex of a chimpanzee. Eighteen months later the animal became ill with CJD. This finding serves to re-emphasise the potential danger posed by reuse of instruments contaminated with the agents of spongiform encephalopathies, even after scrupulous attempts to clean them.

Human spongiform encephalopathy: the National Institutes of Health series of 300 cases of experimentally transmitted disease

We present a synthesis of clinical, neuropathological, and biological details of the National Institutes of Health series of 300 experimentally transmitted cases of spongiform encephalopathy from among more than 1,000 cases of various neurological disorders inoculated into nonhuman primates during the past 30 years. The series comprises 278 subjects with Creutzfeldt-Jakob disease, of whom 234 had sporadic, 36 familial, and 8 iatrogenic disease; 18 patients with kuru; and 4 patients with Gerstmann-Strüssler-Scheinker syndrome. Sporadic Creutzfeldt-Jakob disease, numerically by far the most important representative, showed an average age at onset of 60 years, with the frequent early appearance of cerebellar and visual/oculomotor signs, and a broad spectrum of clinical features during the subsequent course of illness, which was usually fatal in less than 6 months. Characteristic spongiform neuropathology was present in all but 2 subjects. Microscopically visible kuru-type amyloid plaques were found in 5% of patients with Creutzfeldt-Jakob disease, 75% of those with kuru, and 100% of those with Gerstmann-Sträussler-Scheinker syndrome; brain biopsy was diagnostic in 95% of cases later confirmed at autopsy, and proteinase-resistant amyloid protein was identified in Western blots of brain extracts from 88% of tested subjects. Experimental transmission rates were highest for iatrogenic Creutzfeldt-Jakob disease (100%), kuru (95%), and sporadic Creutzfeldt-Jakob disease (90%), and considerably lower for most familial forms of disease (68%). Incubation periods as well as the durations and character of illness showed great variability, even in animals receiving the same inoculum, mirroring the spectrum of clinical profiles seen in human disease. Infectivity reached average levels of nearly 10(5) median lethal doses/gm of brain tissue, but was only irregularly present (and at much lower levels) in tissues outside the brain, and, except for cerebrospinal fluid, was never detected in bodily secretions or excretions.

Severe hyponatraemia in a quadriplegic

A young quadriplegic patient developed convulsions and brain damage due to severe hyponatraemia. Potential causes of severe hyponatraemia in quadriplegics include excessive water intake (because of the low threshold for vasopressin release) and asymptomatic renal tract infection causing sodium loss. Mild hyponatraemia, occurring in up to 10% of quadriplegics, is due to a reset osmostat.

Studies on the placental transfer of cell-free human immunodeficiency virus and p24 antigen in an ex vivo human placental model

OBJECTIVE

We studied whether the human placenta has the structural integrity to impede transplacental passage of cell-free human immunodeficiency virus (HIV)-1 or p24 antigen from the maternal to the fetal circulation.

METHODS

Nine term human placentas from uncomplicated vaginal or cesarean section deliveries were studied ex vivo with a placental perfusion apparatus to determine whether cell-free HIV-1 at 200-2000 tissue culture infectious dose (TCID50/mL) would pass to the fetal circulation. Passage of virus or p24 was assessed by infectivity titration and/or p24 antigen capture enzyme immunoassay.

RESULTS

Infectious HIV-1 was not detected in any of the fetal perfusate samples taken periodically during experiments. Low concentrations of HIV-1 p24 antigen, however, were detected in fetal perfusate samples from three placentas.

CONCLUSIONS

The term human placenta effectively impedes passage of cell-free HIV-1 from the maternal to the fetal circulation. However, it may be permeable to passage of p24 antigen.

Sequence analysis of an immunogenic and neutralizing domain of the human T-cell lymphoma/leukemia virus type I gp46 surface membrane protein among various primate T-cell lymphoma/leukemia virus isolates including those from a patient with both HTLV-I-associated myelopathy and adult T-cell leukemia

Human T-cell lymphoma/leukemia virus type I (HTLV-I) causes adult T-cell leukemia/lymphoma and HTLV-I-associated myelopathy. Specific regions within the outer envelope proteins of other retroviruses, e.g., human immunodeficiency virus type 1, are highly immunogenic and, because of the selective pressure of the host immune system, quite variable. Mutations in the external envelope protein gene of murine retroviruses and human immunodeficiency virus type 1 influence cellular tropism and disease pathogenesis. By contrast, no disease-specific viral mutations have been identified in HTLV-I-infected patients. However, all isolates studied thus far have originated from leukemic cell lines, peripheral blood mononuclear cells, or cerebrospinal fluid lymphocytes from patients with HTLV-I-associated myelopathy and adult T-cell leukemia/lymphoma and, therefore, may not truly reflect tissue-associated variation. The midregion of the HTLV-I gp46 external envelope glycoprotein (amino acids 190-209) induces an antibody response in 90% of infected individuals, and a hexapeptide in this region (amino acids 191-196) elicits antibodies in rabbits which inhibit syncytia formation and infection of target lymphocytes. Because of the above, we expected the neutralizing domain of the gp46 env gene of HTLV-I to possess disease or organ-associated mutations selected by the infected host's immune system. Hence, we amplified, cloned, and sequenced HTLV-I DNA directly from in vivo central nervous system, spleen, and kidney specimens, and a leukemic cell line from a patient (M. J.) with both HTLV-I-associated myelopathy and adult T-cell leukemia/lymphoma to discern the possibility of tissue- and/or disease-specific variants. In addition, we sequenced several HTLV-I isolates from different regions of the world, including Papua New Guinea, Bellona, and Liberia, and compared them to other previously published HTLV-I and related retroviral sequences. The 239-base pair sequence corresponding to amino acids 178 to 256 in gp46 displayed minor tissue-specific variation in clones derived from central nervous system tissues from patient M. J., but overall was highly conserved at both the DNA and amino acid levels. Variation was observed in this region among the other HTLV-I, simian T-cell lymphoma virus type I, and HTLV-II isolates in a pattern that was consistent with their known phylogenetic relationship. No consistent disease-related changes were observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Thermal stability and conformational transitions of scrapie amyloid (prion) protein correlate with infectivity

The scrapie amyloid (prion) protein (PrP27-30) is the protease-resistant core of a larger precursor (PrPSc) and a component of the infectious scrapie agent; the potential to form amyloid is a result of posttranslational event or conformational abnormality. The conformation, heat stability, and solvent-induced conformational transitions of PrP27-30 were studied in the solid state in films by CD spectroscopy and correlated with the infectivity of rehydrated and equilibrated films. The exposure of PrP27-30 in films to 60 degrees C, 100 degrees C, and 132 degrees C for 30 min did not change the beta-sheet secondary structure; the infectivity slightly diminished at 132 degrees C and correlated with a decreased solubility of PrP27-30 in sodium dodecyl sulfate (SDS), probably due to cross-linking. Exposing PrP27-30 films to formic acid (FA), trifluoroacetic acid (TFA), trifluoroethanol (TFE), hexafluoro-2-propanol (HFIP), and SDS transformed the amide CD band, diminished the mean residue ellipticity of aromatic bands, and inactivated scrapie infectivity. The convex constraint algorithm (CAA) deconvolution of the CD spectra of the solvent-exposed and rehydrated solid state PrP27-30 identified five common spectral components. The loss of infectivity quantitatively correlated with a decreasing proportion of native, beta-pleated sheet-like secondary structure component, an increasing amount of alpha-helical component, and an increasingly disordered tertiary structure. The results demonstrate the unusual thermal stability of the beta-sheet secondary structure of PrP27-30 protein in the solid state. The conformational perturbations of PrP27-30 parallel the changes in infectivity and suggest that the beta-sheet structure plays a key role in the physical stability of scrapie amyloid and in the ability to propagate and replicate scrapie.

A new (two-repeat) octapeptide coding insert mutation in Creutzfeldt-Jakob disease

We report a family in which the proband died of clinically typical, neuropathologically verified Creutzfeldt-Jakob disease; her still-living mother suffers from a progressive dementia of many years' duration, and her maternal grandfather died after a similar illness. The proband, her mother, and two of three young first-degree relatives all have an identical insert mutation in the PRNP gene consisting of a twice-repeated 24-nucleotide sequence in the region between codons 51 and 91.

Conformational transitions, dissociation, and unfolding of scrapie amyloid (prion) protein

The infectious form of the scrapie amyloid (prion) precursor, PrPSc, is a host-derived protein and a component of the infectious agent causing scrapie. PrPSc and the carboxyl-terminal proteinase K resistant core, PrP27-30, have the potential to form amyloid as a result of a post-translational event or conformational abnormality. We have studied the conformational transitions of both proteins reconstituted into liposomes, associated in solid state in thin films, and dissociated by guanidine HCl. The secondary structure of PrPSc in liposomes deduced from analysis of circular dichroism spectra contained approximately 34% beta-sheets, approximately 20% alpha-helix, and approximately 46% beta-turns and random coil. Cleavage of the amino-terminal region of PrPSc resulted in all-beta PrP27-30, with an estimated approximately 43% beta-sheet, no alpha-helix, and approximately 57% beta-turns and random coil. The PrPSC associated in thin films with a tertiary structure perturbation corresponding to unfolding, while the secondary structure was preserved. The PrP27-30 assembled into the solid state with a similar perturbation of tertiary structure but with a large increase in the beta-sheet content, probably due to an intermolecular alignment of the external beta-sheets, or to a secondary structure transition, or both. The various conformational states had little or no impact on infectivity. Equilibrium dissociation and unfolding demonstrated a greater resistance of PrP27-30 to denaturation. The dissociated monomers unfolded through intermediate(s), suggesting the presence of protein domains with distinct secondary structure stabilities. The results provide experimental evidence for the beta-sheet type assembly of scrapie amyloid PrP27-30 in the solid state and demonstrate the importance of amino-terminal cleavage in the stability and alignment of the amyloid-forming monomers.

Secondary structure of proteins associated in thin films

The solid state secondary structure of myoglobin, RNase A, concanavalin A (Con A), poly(L-lysine), and two linear heterooligomeric peptides were examined by both far-uv CD spectroscopy1 and by ir spectroscopy. The proteins associated from water solution on glass and mica surfaces into noncrystalline, amorphous films, as judged by transmission electron microscopy of carbon-platinum replicas of surface and cross-fractured layer. The association into the solid state induced insignificant changes in the amide CD spectra of all alpha-helical myoglobin, decreased the molar ellipticity of the alpha/beta RNase A, and increased the molar ellipticity of all-beta Con A with no change in the positions of the bands' maxima. High-temperature exposure of the films induced permanent changes in the conformation of all proteins, resulting in less alpha-helix and more beta-sheet structure. The results suggest that the protein alpha-helices are less stable in films and that the secondary structure may rearrange into beta-sheets at high temperature. Two heterooligomeric peptides and poly(L-lysine), all in solution at neutral pH with "random coil" conformation, formed films with variable degrees of their secondary structure in beta-sheets or beta-turns. The result corresponded to the protein-derived Chou-Fasman amino acid propensities, and depended on both temperature and solvent used. The ir and CD spectra correlations of the peptides in the solid state indicate that the CD spectrum of a "random" structure in films differs from random coil in solution. Formic acid treatment transformed the secondary structure of the protein and peptide films into a stable alpha-helix or beta-sheet conformations. The results indicate that the proteins aggregate into a noncrystalline, glass-like state with preserved secondary structure. The solid state secondary structure may undergo further irreversible transformations induced by heat or solvent.

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.

Long-term observations of human immunodeficiency virus-infected chimpanzees

Twenty-seven chimpanzees inoculated with material presumed to contain human immunodeficiency virus (HIV) between June 1983 and February 1985 were studied. The animals were examined on four to six occasions between 1989 and 1992 for serologic, virologic, hematologic, immunophenotypic, as well as clinical signs of HIV infection and compared to five uninfected control animals. The 19 animals that had seroconverted within 244 days of inoculation remained antibody positive, whereas those that did not seroconvert within 244 days of inoculation remained antibody negative 6 to 8 years later. HIV antigen was demonstrated at least once in lymphocyte cultures from 12 of the 19 antibody positive chimpanzees during this period. Nested polymerase chain reaction amplified proviral DNA in lymphocytes from 14 of the 19 animals. No proviral DNA was detected in antibody-negative animals. Antibody titers were generally higher in animals from which virus was recovered in lymphocyte cultures [granulocyte-macrophage (GM) titer, 1:8427] compared to virus-negative animals (GM titer, 1:3608). Mean total white blood cell and lymphocyte subtype counts were similar in the HIV-infected animals and uninfected controls. The high antibody levels and Western blot profiles, over periods as long as 9 years in these chimpanzees, suggest continuous stimulation of the immune system by HIV antigen although virus was detected only sporadically in the peripheral blood. No illness suggestive of immunodeficiency was seen.

Real and imagined clinicopathological limits of "prion dementia"

The term "prion dementia" has been proposed to replace "spongiform encephalopathy", to accommodate the existence of atypical forms of these "prion protein" (PrP) cerebral amyloidoses that may not show spongiform changes in the brain. We tested brain tissue extracts for the presence of PrP from 46 cases (including 13 familial cases) of non-spongiform dementias with a variety of associated neurological signs, referred to our laboratory for primate transmission studies. None of the cases transmitted disease to primates, and none had PrP detectable by western immunoblots of extracted brain tissue. We conclude that prion dementias are not lurking undetected within the larger landscape of neurodegenerative disorders, and that their clinicopathological limits are, except for a small number of previously reported familial cases, essentially those of spongiform encephalopathy.

Inactivation of the scrapie agent in a scaled-down procedure for the purification of gangliosides from brain tissue

The inactivation of the scrapie agent in biologicals was evaluated on a scaled-down procedure currently in use on a large scale for the purification of gangliosides from bovine brain tissue. Residual infectivity was determined by an in vivo animal bio-assay using hamsters as the host species and the 263K strain as the reference agent. Infectivity was significantly diminished during the early stages of purification and infectivity was never detected in the final preparations. These results confirmed that a combination of chemicals or physical techniques known to affect the viability of the scrapie agent led to complete inactivation.