Dimethyl fumarate decreases short-term but not long-term inflammation in a focal EAE model of neuroinflammation.

BACKGROUND: Dimethyl fumarate (DMF) is an oral immunomodulatory drug used in the treatment of autoimmune diseases. Here, we sought to study whether the effect of DMF can be detected using positron emission tomography (PET) targeting the 18-kDa translocator protein (TSPO) in the focal delayed-type hypersensitivity rat model of multiple sclerosis (fDTH-EAE). The rats were treated orally twice daily from lesion activation (day 0) with either vehicle (tap water with 0.08% Methocel, 200 µL; control group n = 4 (3 after week four)) or 15 mg/kg DMF (n = 4) in 0.08% aqueous Methocel (200 µL) for 8 weeks. The animals were imaged by PET using the TSPO tracer [18F]GE-180 in weeks 0, 1, 2, 4, 8, and 18 following lesion activation, and the non-displaceable binding potential (BPND) was calculated. Immunohistochemical staining for Iba1, CD4, and CD8 was performed in week 18, and in separate cohorts of animals, following 2 or 4 weeks of treatment. RESULTS: Using the fDTH-EAE model, DMF reduced the [18F]GE-180 BPND in the DMF-treated animals compared to control animals after 1 week of treatment (two-tailed unpaired t test, p = 0.031), but not in weeks 2, 4, 8, or 18 when imaged in vivo by PET. Immunostaining for Iba1 showed that DMF had no effect on the perilesional volume or the core lesion volume after 2 or 4 weeks of treatment, or at 18 weeks. However, the optical density (OD) measurements of CD4+ staining showed reduced OD in the lesions of the treated rats. CONCLUSIONS: DMF reduced the microglial activation in the fDTH-EAE model after 1 week of treatment, as detected by PET imaging of the TSPO ligand [18F]GE-180. However, over an extended time course, reduced microglial activation was not observed using [18F]GE-180 or by immunohistochemistry for Iba1+ microglia/macrophages. Additionally, DMF did affect the infiltration of CD4+ and CD8+ T-lymphocytes at the fDTH-EAE lesion.

The E280A presenilin 1 Alzheimer mutation produces increased A beta 42 deposition and severe cerebellar pathology.

Missense mutations in the presenilin 1 (PS1) gene cause the most common form of dominant early-onset familial Alzheimer's disease (FAD) and are associated with increased levels of amyloid beta-peptides (A beta) ending at residue 42 (A beta 42) in plasma and skin fibroblast media of gene carriers. A beta 42 aggregates readily and appears to provide a nidus for the subsequent aggregation of A beta 40 (ref. 4), resulting in the formation of innumerable neuritic plaques. To obtain in vivo information about how PS1 mutations cause AD pathology at such early ages, we characterized the neuropathological phenotype of four PS1-FAD patients from a large Colombian kindred bearing the codon 280 Glu to Ala substitution (Glu280Ala) PS1 mutation. Using antibodies specific to the alternative carboxy-termini of A beta, we detected massive deposition of A beta 42, the earliest and predominant form of plaque A beta to occur in AD (ref. 6-8), in many brain regions. Computer-assisted quantification revealed a significant increase in A beta 42, but not A beta 40, burden in the brains from 4 PS1-FAD patients compared with those from 12 sporadic AD patients. Severe cerebellar pathology included numerous A beta 42-reactive plaques, many bearing dystrophic neurites and reactive glia. Our results in brain tissue are consistent with recent biochemical evidence of increased A beta 42 levels in PS1-FAD patients and strongly suggest that mutant PS1 proteins alter the proteolytic processing of the beta-amyloid precursor protein at the C-terminus of A beta to favor deposition of A beta 42.

Cessation of anti-VLA-4 therapy in a focal rat model of multiple sclerosis causes an increase in neuroinflammation.

BACKGROUND: Positron emission tomography (PET) can be used for in vivo evaluation of the pathology associated with multiple sclerosis. We investigated the use of longitudinal PET imaging and the 18-kDa translocator protein (TSPO) binding radioligand [18F]GE-180 to detect changes in a chronic multiple sclerosis-like focal delayed-type hypersensitivity experimental autoimmune encephalomyelitis (fDTH-EAE) rat model during and after anti-VLA-4 monoclonal antibody (mAb) treatment. Thirty days after lesion activation, fDTH-EAE rats were treated with the anti-VLA-4 mAb (n = 4) or a control mAb (n = 4; 5 mg/kg, every third day, subcutaneously) for 31 days. Animals were imaged with [18F]GE-180 on days 30, 44, 65, 86 and 142. Another group of animals (n = 4) was used for visualisation the microglia with Iba-1 at day 44 after a 2-week treatment period. RESULTS: After a 2-week treatment period on day 44, there was a declining trend (p = 0.067) in [18F]GE-180-binding in the anti-VLA-4 mAb-treated animals versus controls. However, cessation of treatment for 4 days after a 31-day treatment period increased [18F]GE-180 binding in animals treated with anti-VLA-4 mAb compared to the control group (p = 0.0003). There was no difference between the groups in TSPO binding by day 142. CONCLUSIONS: These results demonstrated that cessation of anti-VLA-4 mAb treatment for 4 days caused a transient rebound increase in neuroinflammation. This highlights the usefulness of serial TSPO imaging in the fDTH-EAE model to better understand the rebound phenomenon.

Small-scale environmental enrichment and exercise enhance learning and spatial memory of Carassius auratus, and increase cell proliferation in the telencephalon: an exploratory study.

Carassius auratus is a teleost fish that has been largely used in behavioral studies. However, little is known about potential environmental influences on its performance of learning and memory tasks. Here, we investigated this question in C. auratus, and searched for potential correlation between exercise and visuospatial enrichment with the total number of telencephalic glia and neurons. To that end, males and females were housed for 183 days in either an enriched (EE) or impoverished environment (IE) aquarium. EE contained toys, natural plants, and a 12-hour/day water stream for voluntary exercise, whereas the IE had none of the above. A third plus-maze aquarium was used for spatial and object recognition tests. Different visual clues in 2 of its 4 arms were used to guide fish to reach the criteria to complete the task. The test consisted of 30 sessions and was concluded when each animal performed three consecutive correct choices or seven alternated, each ten trials. Learning rates revealed significant differences between EE and IE fish. The optical fractionator was used to estimate the total number of telencephalic cells that were stained with cresyl violet. On average, the total number of cells in the subjects from EE was higher than those from subjects maintained in IE (P=0.0202). We suggest that environmental enrichment significantly influenced goldfish spatial learning and memory abilities, and this may be associated with an increase in the total number of telencephalic cells.

Inhibition of peripheral TNF can block the malaise associated with CNS inflammatory diseases.

Circulating cytokine levels are elevated in many neuropathologies and may be a cause of the associated malaise and depression. Using a rat model, we demonstrate that sickness behaviors generated by microinjection of IL-1beta into the anterior hypothalamus are adopted by naive recipient animals following plasma transfer. We further show that neutralizing peripheral TNF by etanercept (a p75 TNF receptor/Fc fusion protein) prior to the IL-1beta microinjection inhibits certain IL-1beta-mediated sickness behaviors, such as the depression of open-field activity and reduced glucose consumption. IL-1beta-induced central lesions induce peripheral TNF as part of the acute-phase response, and this appears to be the principal target of the etanercept. Thus behavioral changes induced by CNS lesions may result from peripheral expression of cytokines that can be targeted with drugs which do not need to cross the blood-brain barrier to be efficacious.

Stroke: a double-edged sword for cleaving clots?

The discovery that tissue plasminogen activator can promote neuronal degeneration has uncovered a novel pathway leading to neuronal cell death and raises important issues concerning the use of tissue plasminogen activator as a thrombolytic therapy for stroke.

Transient expression of IL-1beta induces acute lung injury and chronic repair leading to pulmonary fibrosis.

IL-1beta is one of a family of proinflammatory cytokines thought to be involved in many acute and chronic diseases. Although it is considered to participate in wound repair, no major role has been attributed to IL-1beta in tissue fibrosis. We used adenoviral gene transfer to transiently overexpress IL-1beta in rat lungs after intratracheal administration. The high expression of IL-1beta in the first week after injection was accompanied by local increase of the proinflammatory cytokines IL-6 and TNF-alpha and a vigorous acute inflammatory tissue response with evidence of tissue injury. The profibrotic cytokines PDGF and TGF-beta1 were increased in lung fluid samples 1 week after peak expression of IL-1beta. Although PDGF returned to baseline in the third week, TGF-beta1 showed increased concentrations in bronchoalveolar lavage fluid for up to 60 days. This was associated with severe progressive tissue fibrosis in the lung, as shown by the presence of myofibroblasts, fibroblast foci, and significant extracellular accumulations of collagen and fibronectin. These data directly demonstrate how acute tissue injury in the lung, initiated by a highly proinflammatory cytokine, IL-1beta, converts to progressive fibrotic changes. IL-1beta should be considered a valid target for therapeutic intervention in diseases associated with fibrosis and tissue remodeling.

Age and Environment Influences on Mouse Prion Disease Progression: Behavioral Changes and Morphometry and Stereology of Hippocampal Astrocytes.

Because enriched environment (EE) and exercise increase and aging decreases immune response, we hypothesized that environmental enrichment and aging will, respectively, delay and increase prion disease progression. Mice dorsal striatum received bilateral stereotaxic intracerebral injections of normal or ME7 prion infected mouse brain homogenates. After behavior analysis, animals were euthanized and their brains processed for astrocyte GFAP immunolabeling. Our analysis related to the environmental influence are limited to young adult mice, whereas age influence refers to aged mice raised on standard cages. Burrowing activity began to reduce in ME7-SE two weeks before ME7-EE, while no changes were apparent in ME7 aged mice (ME7-A). Object placement recognition was impaired in ME7-SE, NBH-A, and ME7-A but normal in all other groups. Object identity recognition was impaired in ME7-A. Cluster analysis revealed two morphological families of astrocytes in NBH-SE animals, three in NBH-A and ME7-A, and four in NBH-EE, ME7-SE, and ME7-EE. As compared with control groups, astrocytes from DG and CA3 prion-diseased animals show significant numerical and morphological differences and environmental enrichment did not reverse these changes but induced different morphological changes in GFAP+ hippocampal astroglia. We suggest that environmental enrichment and aging delayed hippocampal-dependent behavioral and neuropathological signs of disease progression.

Detection of the inhibitory neurotransmitter GABA in macrophages by magnetic resonance spectroscopy.

Macrophages are key components of the inflammatory response to tissue injury, but their activities can exacerbate neuropathology. High-resolution magnetic resonance spectroscopy was used to identify metabolite levels in perchloric acid extracts of cultured cells of the RAW 264.7 murine macrophage line under resting and lipopolysaccharide-activated conditions. Over 25 metabolites were identified including gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter not previously reported to be present in macrophages. The presence of GABA was also demonstrated in extracts of human peripheral blood monocyte-derived macrophages. This finding suggests that there may be communication between damaged central nervous system (CNS) tissue and recruited macrophages and resident microglia, which could help orchestrate the immune response. On activation, lactate, glutamine, glutamate, and taurine levels were elevated significantly, and GABA and alanine were reduced significantly. Strong resonances from glutathione, evident in the macrophage two-dimensional 1H spectrum, suggest that this may have potential as a noninvasive marker of macrophages recruited to the CNS, as it is only present at low levels in normal brain. Alternatively, a specific combination of spectroscopic changes, such as lactate, alanine, glutathione, and polyamines, may prove to be the most accurate means of detecting macrophage recruitment to the CNS.

MDR1 gene-specific monoclonal antibody C494 cross-reacts with pyruvate carboxylase.

Overexpression of P-glycoprotein, the plasma membrane protein product of the MDR1 gene, is a major determinant in the development of resistance to a large number of cancer chemotherapeutic agents. A battery of antibodies, including the MDR1 gene-specific monoclonal antibody (mAb) C494, is used to evaluate human tissues in clinical multidrug resistance surveillance and modulation trials. In rat liver fractions, we report that mAb C494 strongly cross-reacted with a nonmembranous M(r) approximately 130,000 protein, comigrating with core-glycosylated human MDR1 on 7% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. By immunoblotting and microsequence analysis, this protein was identified as pyruvate carboxylase (PC), an abundant mitochondrial enzyme. A search of the National Center for Biotechnology Information data base, using the epitope-specific sequence of mAb C494, revealed that PC (mouse) contains four of the five most reactive amino acids (TLEG), located near the COOH-terminal end of PC at positions 1167-1170. mAb C494 specifically reacted with PC purified from bovine liver; immunoreactivity was completely abolished by preincubating mAb C494 in the presence of excess synthetic C494 epitope-specific peptide. Furthermore, in cryosections of human skeletal muscle, a tissue known not to express P-glycoprotein, peptide-displaceable immunohistochemical staining with mAb C494 showed a distinct mitochondrial pattern specific to type 1 fibers. Variable immunostaining results were obtained with formaldehyde-fixed, paraffin-embedded muscle and isolated liver mitochondrial preparations. In summary, mAb C494 cross-reacted strongly with rat, bovine, and human PC. Caution is warranted in interpretation of immunoblots and immunohistochemical sections with this putative MDR1 gene-specific mAb.

Interleukin-1beta -induced changes in blood-brain barrier permeability, apparent diffusion coefficient, and cerebral blood volume in the rat brain: a magnetic resonance study.

The cytokine interleukin-1beta (IL-1beta) is implicated in a broad spectrum of CNS pathologies, in which it is thought to exacerbate neuronal loss. Here, the effects of injecting recombinant rat IL-1beta into the striatum of 3-week-old rats were followed noninvasively from 2 to 123 hr using magnetic resonance imaging and spectroscopy. Four hours after injection of IL-1beta (1 ng in 1 microliter), cerebral blood volume was significantly increased, the blood-brain barrier (BBB) became permeable to intravenously administered contrast agent between 4.5 and 5 hr, and the apparent diffusion coefficient (ADC) of brain water fell by 6 hr (5.42 +/- 0. 35 x 10(-4) mm(2)/sec treated, 7.35 +/- 0.77 x 10(-)(4) mm(2)/sec control; p < 0.001). At 24 hr the BBB was again intact, but the ADC, although partially recovered, remained depressed at both 24 and 123 hr (p < 0.03). Depleting the animals of neutrophils before IL-1beta injection prevented the BBB permeability at all time points, but the ADC was still depressed at 6 hr (6.64 +/- 0.34 x 10(-4) mm(2)/sec treated, 7.49 +/- 0.38 x 10(-4) mm(2)/sec control; p < 0.005). No changes were seen in brain metabolites using proton spectroscopy at 6 hr after IL-1beta. Intraparenchymal injection of IL-1beta caused a neutrophil-dependent transient increase in BBB permeability. The presence of neutrophils within the brain parenchyma significantly contributed to the IL-1beta-induced changes in cerebral blood volume and the ADC of brain water. However, IL-1beta apparently had a direct effect on the resident cell populations, which persisted well after all recruited leukocytes had disappeared. Thus the action of IL-1beta alone can give rise to magnetic resonance imaging-visible changes that are normally attributed to alterations to cellular homeostasis.

The spatio-temporal pattern of the axonopathy associated with the neurotoxicity of 3,4-dimethyl-2,5-hexanedione in the rat.

The neurotoxicity of the gamma-diketone 3,4-dimethyl-2,5-hexanedione(DMHD) was studied to determine the distribution of the neuropathologic changes and the temporal sequence during the intoxication period and following five and 15 weeks of recovery. Intoxication with 3,4-dimethyl-2,5-hexanedione at a daily dose of 0.25 mmoles/kg led to a profound clinical neuropathy, resulting in paralysis of all four limbs after 12-15 days. The cumulative toxic dose for this gamma-diketone was 3-4 mmoles/kg, indicating that dimethyl substitution increased the neurotoxicity of gamma-diketones by a factor of 20-30. The neuropathy was characterized histologically by giant axonal swellings in the proximal axon of the lower motor neuron in a distribution similar to IDPN (beta,beta'-iminodipropionitrile)-neuropathy, with swellings in the anterior horn, intraspinal anterior root, and the proximal anterior root. These swellings developed from six to 12 days of intoxication and were still evident after 15 weeks of recovery. The fact that dimethyl substitution of 2,5-hexanedione accelerated the neuropathy and was characterized by proximal axonal swellings has two important implications: 1) that formation of pyrrole derivatives may be an important step in the pathogenesis of gamma-diketone neuropathies, and 2) that the neurofilament neuropathies may represent a continuum of toxic neuropathies in which the rate of action of the neurotoxin ultimately determines the proximo-distal location of the axonal swellings.

The role of pyrrole formation in the alteration of neurofilament transport induced during exposure to 2,5-hexanedione.

Exposure to the gamma-diketone, 2,5-hexanedione (HD), results in the accumulation of neurofilaments within the distal axon and is associated with acceleration of neurofilament transport within the proximal axon. The epsilon-amino groups of lysyl residues react with HD forming pyrrole adducts, followed by pyrrole-mediated protein crosslinking. Both reaction steps have been proposed as mechanisms causing neurofilament accumulation and acceleration of transport. In order to assess the importance of these steps on neurofilament transport, we compared transport in the optic system of rats exposed to HD and 3-acetyl-2,5-hexanedione (AcHD), a non-toxic analog of HD which forms pyrroles but does not crosslink proteins. Control, HD-treated, and AcHD-treated rats received intraoptic injections of [35S]-methionine and were exposed to saline, HD, or AcHD by intraperitoneal injections before and during the period of neurofilament transport. Neurofilament triplet proteins in the optic nerve and tract were identified by polyacrylamide gel electrophoresis followed by fluorography. The rate of neurofilament transport was accelerated in HD-treated animals over that of controls. However, despite higher levels of protein-bound pyrroles in AcHD-treated animals, the rate of transport was indistinguishable from that of controls. These findings indicate that pyrrole formation alone is not sufficient to cause acceleration of neurofilament transport.

Comparison of location, severity, and dose response of proximal axonal lesions induced by 3,3'-iminodipropionitrile and deuterium substituted analogs.

Administration of 3,3'-iminodipropionitrile (IDPN) to rats results in massive accumulation of tangled neurofilaments in the proximal axons of large neurons, such as in dorsal root ganglia (DRG) and ventral horns of the lumbar spinal cord (LSC). Clinically, rats develop hyperexcitability, circling, head bobbing, and retropulsion. The ultimate toxicant and the molecular mechanism are not known. In a study designed to explore potential activation and detoxification pathways, dose-related differences in location and severity of lesions were observed in rats treated with IDPN or deuterium substituted analogs, 2,2,2',2'-tetradeuterio-IDPN (2-d-IDPN) or 3,3,3',3'-tetradeuterio-IDPN (3-d-IDPN). The compounds or saline were administered intraperitoneally to three rats per group at dose levels of 3.0, 1.5, 1.0, and 0.0 mmole/kg/day for 3 days. One week after the initial dose, tissues from DRG and LSC were collected, prepared and evaluated histologically in zones extending from areas adjacent to the cell bodies, distally toward the DRG stalk or toward the lumbar spinal roots. In the low dose IDPN group, DRG and LSC lesions were most prominent in distal zones. As dosage increased, the lesions progressed in severity and in proximity to the cell bodies. At the high dose, lesions were prominent in all zones. The same general pattern occurred with both analogs, although 2-d-IDPN was less potent than IDPN and 3-d-IDPN was more potent than IDPN. The differences in potency from the secondary isotopic effect of deuterium suggest that the 3-position is important in detoxification while the 2-position is important in the bioactivation of IDPN.

Cytokine-induced acute inflammation in the brain and spinal cord.

Different compartments in the central nervous system mount distinct inflammatory responses. The meninges and choroid plexus respond to pro-inflammatory stimuli in a manner reminiscent of a peripheral inflammatory response, whereas the brain parenchyma is refractory. Trauma-induced lesions in brain and in spinal cord are associated with leukocyte infiltration, blood-brain barrier (BBB) breakdown, and secondary tissue destruction. Unexpectedly, these phenomena are generally more pronounced in the parenchyma of the spinal cord than in the parenchyma of the brain. To investigate whether these differences between brain and spinal cord can be attributed, at least in part, to differing sensitivities to proinflammatory cytokines, we stereotactically injected recombinant rat (rr) TNFalpha or rrIL-1beta into the striatum or the spinal cord of Wistar rats. In the brain, the injection of rrTNFalpha failed to evoke BBB breakdown or leukocyte recruitment, whereas in the spinal cord injection of TNFalpha resulted in marked BBB breakdown and leukocyte recruitment. Similarly, the injection of rrIL-1beta into the brain parenchyma failed to induce BBB breakdown and gave rise to only minimal neutrophil recruitment, whereas the injection of rrIL-1beta into the spinal cord induced significant BBB breakdown and recruitment of neutrophils and lymphocytes. Thus, using a minimally invasive injection technique, equivalent in both circumstances, we have shown that there are marked differences in the inflammatory response between the brain parenchyma and spinal cord parenchyma. This observation has important implications for the treatment of spinal cord injuries.

Focal lesions in the rat central nervous system induced by endothelin-1.

Axon injury following cerebral ischemia has received little scientific attention compared to the abundance of information dealing with the pathophysiology of grey matter ischemia. There are differences in the initial response of grey and white matter to ischemia in vitro. In this study we investigate whether the vasoactive peptide, endothelin-1, can generate a focal ischemic lesion in the white matter and compare the findings with endothelin-1-induced lesions in the grey matter. Using a minimally invasive technique to microinject endothelin-1 into selected brain regions, we observed an acute reduction in local MRI perfusion in the injected hemisphere after 1 hour. Twenty-four hours after microinjection of 10 pmoles of endothelin-1, we observed a loss of neurons in the grey matter. At 72 hours, neutrophils were absent and a macrophage/microglia response and astrocyte gliosis were detected. No breakdown in the blood-brain barrier was detected. After injection of 10 pmoles endothelin-1 into the cortical white matter, we observed prolific amyloid precursor protein-positive immunostaining (indicative of axonal disruption) and an increase in tau-1 immunostaining in oligodendrocytes at 6 hours. Similar to the grey matter lesions, no neutrophils were present, a macrophage/microglia response did not occur until 72 hours and there was no disruption in the blood-brain barrier. Focal injections of endothelin-1 into specific areas of the rat CNS represent a model to investigate therapeutic approaches to white matter ischemia.

August 2000: Two cases with necrosis and hemorrhage in the putamen and white matter.

The August COM: Acute methanol poisoning is an uncommon, but well-recognized, cause of central nervous system injury. We present two autopsy cases showing the classic neuropathologic injuries in acute methanol poisoning: putamen and white matter necrosis and hemorrhage. In Case 1, putamen hemorrhages were striking; white matter pathology predominated in Case 2. The precise mechanism of methanol toxicity is unclear. Direct toxicity of metabolites, particularly formic acid, as well as ischemic injury and acidosis likely play a role. Methanol is readily available in many commercial products, and may be ingested accidentally or intentionally.

Recruitment of neutrophils across the blood-brain barrier: the role of E- and P-selectins.

The adult central nervous system parenchyma is resistant to inflammation, but in juvenile rats the injection of inflammatory mediators, interleukin-1 beta for example, gives rise to extensive neutrophil recruitment and neutrophil-dependent blood-brain barrier breakdown. The factors that confer this resistant phenotype are unknown. In this study, the authors demonstrate that E- and P-selectin expression is increased to a similar extent in adult and juvenile brain after the intracerebral injection of IL-1 beta. Thus, the refractory nature of the brain parenchyma cannot be attributed to an absence of selectin expression. However, in injuries where the resistant characteristic of the brain parenchyma is compromised, and neutrophil recruitment occurs, selectin blockade may be an advantage. The authors investigated the contribution that selectins make to neutrophil recruitment during acute inflammation in the brain. The authors examined neutrophil recruitment by immunohistochemistry on brain sections of juvenile rats killed four hours after the intracerebral injection of IL-1 beta and the intravenous injection of neutralizing anti-selectin monoclonal antibodies (mAb). The administration of the P-selectin blocking mAb inhibited neutrophil recruitment by 85% compared with controls. Surprisingly, E-selectin blockade had no effect on neutrophil recruitment to the brain parenchyma. Thus, P-selectin appears to play a pivotal role in mediating neutrophil recruitment to the brain parenchyma during acute inflammation.

Quantification of microheterogeneity in glioblastoma multiforme with ex vivo high-resolution magic-angle spinning (HRMAS) proton magnetic resonance spectroscopy.

Microheterogeneity is a routinely observed neuropathologic characteristic in brain tumor pathology. Although microheterogeneity is readily documented by routine histologic techniques, these techniques only measure tumor status at the time of biopsy or surgery and do not indicate likely tumor progression. A biochemical screening technique calibrated against pathologic standards would greatly assist in predicting tumor progression from its biological activity. Here we demonstrate for the first time that proton magnetic resonance spectroscopy (1H MRS) with high-resolution magic-angle spinning (HRMAS), a technique introduced in 1997, can preserve tissue histopathologic features while producing well-resolved spectra of cellular metabolites in the identical intact tissue specimens. Observed biochemical alterations and tumor histopathologic characteristics can thus be correlated for the same surgical specimen, obviating the problems caused by tumor microheterogeneity. We analyzed multiple specimens of a single human glioblastoma multiforme surgically removed from a 44-year-old patient. Each specimen was first measured with HRMAS 1H MRS to determine tumor metabolites, then evaluated by quantitative histopathology. The concentrations of lactate and mobile lipids measured with HRMAS linearly reflected the percentage of tumor necrosis. Moreover, metabolic ratios of phosphorylcholine to choline correlated linearly with the percentage of the highly cellular malignant glioma. The quantification of tumor metabolic changes with HRMAS 1H MRS, in conjunction with subsequent histopathology of the same tumor specimen, has the potential to further our knowledge of the biochemistry of tumor heterogeneity during development, and thus ultimately to improve our accuracy in diagnosing, characterizing, and evaluating tumor progression.

A case of myelinoclastic diffuse sclerosis in an adult.

We report a case of rapidly progressive cerebral demyelinating disease in a previously healthy 40-year-old woman. This case satisfies the diagnostic criteria for myelinoclastic diffuse sclerosis (MDS), but is unusual in the age of onset. This is the 1st case of MDS in an adult with full documentation of clinical, biochemical, radiographic, and pathologic features.