Advantages of using recombinant measles viruses expressing a fluorescent reporter gene with vibratome slice technology in experimental measles neuropathogenesis

AIMS

In this study of experimental measles neuropathogenesis, the utility of enhanced green fluorescent protein (EGFP) as a sensitive indicator of measles virus (MV) cell-to-cell spread in the central nervous system (CNS) has been assessed in vibratome-cut brain slices to demonstrate the degree and mechanism of viral spread in the rodent CNS.

METHODS

Recombinant MVs expressing EGFP were visualized at different levels in 200-microm vibratome-cut brain sections from infected animals by confocal scanning laser microscopy (CSLM). Comparison was made with 7-microm microtome sections, stained for the N protein of measles by immunocytochemistry (ICC).

RESULTS

The recombinant viruses were readily visualized in infected brain tissue, with no loss of neuropathogenicity. No difference was found in the sites of infection when MV infection was detected through EGFP fluorescence or by ICC. MV-infected cells were detected in the cerebral cortex, olfactory bulb and tract, hippocampus, thalamus, hypothalamus, ependyma and subventricular zone. However, the 200-microm vibratome-cut sections and confocal microscopy proved excellent for demonstrating virus distribution in neurites and for in-depth analysis of the extent of tract infection in the white matter of the cerebral hemispheres such as selective infection of the internal capsule and anterior commissure.

CONCLUSIONS

The use of self-tracing recombinant MVs, viewed in thick vibratome-cut sections by CSLM, demonstrated that in experimental MV neuropathogenesis the infection is selective and spreads predominately by neurites using defined anatomical pathways.

Pathological abnormalities in the normal-appearing white matter in multiple sclerosis

In established cases of multiple sclerosis (MS), the normal-appearing white matter (NAWM), as defined for magnetic resonance imaging (MRI), is abnormal in the majority of cases. The clinical significance of these NAWM abnormalities is the subject of debate, but there is strong correlation with degree and progression of disability. New lesions form in NAWM before blood-brain barrier breakdown, as evidenced by gadolinium enhancement. The pathological basis of these neuroimaging abnormalities is largely unknown. Definitive pathological studies on the NAWM are few and are often based on small numbers of samples and of cases. Despite a variety of MS NAWM pathological studies, major research questions, of importance to our understanding of basic pathogenetic mechanisms and consequent rational therapies, remain unanswered. These relate to the frequency and extent of oligodendrocyte/myelin and axonal abnormalities in MS NAWM, and to the cellular basis of very early MS lesions detected by neuroimaging. In a pilot study of MS NAWM, microglial activation was demonstrated in 9 of 10 MS cases. We are currently testing the hypothesis that microglial activation, as defined by altered phenotype and HLA-DR positivity, will act as a marker for oligodendrocyte/myelin and axonal pathology in MS NAWM.

Cortical lesions in multiple sclerosis

Although previous studies have shown that the lesions of multiple sclerosis may involve the cerebral cortex, there is little published research on the prevalence and distribution of such lesions. Using neuropathological techniques and MRI, a series of studies has been undertaken in order to assess this, in particular to identify their relationship to cortical veins. A serial MRI study showed that the use of gadolinium proffered an increase in cortical lesion detection of 140% and showed that 26% of active lesions arose within or adjacent to the cortex. In a post-mortem study, MRI under-reported lesions subsequently analysed neuropathologically, particularly those arising within the cortex. In a further 12 cases examined, 478 cortical lesions were identified, of which 372 also involved the subcortical white matter. Seven different lesion types were identified; the majority arose within the territory of the principal cortical veins, whilst the remaining quarter arose within the territory of the small branch or superficial veins. Small cortical lesions are common in multiple sclerosis and are under-reported by MRI. Investigation of the cortical venous supply shows how such lesions may arise, and why the majority also involve the underlying white matter.

Prion protein immunocytochemistry--UK five centre consensus report

Creutzfeldt-Jakob disease (CJD) and other prion diseases are associated with the deposition of insoluble prion protein (PrPCJD) in the central nervous system (CNS). Antibodies raised against PrPCJD also react with its precursor protein, a soluble form of PrP (PrPC), which is widely distributed in the normal CNS. This cross-reactivity has in the past raised doubts as to the specificity and diagnostic reliability of PrP immunolocalization, especially in familial cases which are atypical clinically and which lack characteristic pathology findings. Following an MRC-funded workshop which focused on this problem, a multicentre prospective study was set up to identify a reliable protocol for PrPCJD immunocytochemistry. Five UK centres took part in this study and demonstrated consistent staining of plaques, vacuolar deposits in severe spongiform change, and perineuronal deposits using a variety of antibodies and enhancement procedures. A protocol using formic acid, guanidine thiocyanate, and hydrated autoclaving pre-treatment in conjunction with a monoclonal PrPCJD antibody produced the clearest immunochemical results and is presented as the consensus UK recommendation for PrPCJD immunocytochemical procedures.

The significance of measles virus antigen and genome distribution in the CNS in SSPE for mechanisms of viral spread and demyelination

The distribution of measles virus (MV) antigen and genomic RNA in the central nervous system (CNS) in 10 cases of subacute sclerosing panencephalitis (SSPE) was determined using optimized immunocytochemistry and in situ hybridization techniques. As in previous reports neurons and oligodendrocytes were found to be the most frequently infected cells. It was confirmed that MV infection in neuronal processes was predominantly dendritic but there was also some evidence suggestive of occasional axonal involvement, a finding confirmed by electron microscopy. In addition MV genomic RNA was detected in neuronal processes, in some cases in the absence of demonstrable MV antigen. The relationship between myelin destruction and oligodendrocytic infection suggested that the demyelination may be solely the result of virus infection. A possible correlation between viral distribution and form and the clinical duration of disease was examined. Viral antigen and genome were equally abundant in the cerebral cortex in most short duration cases (<6 months). However, in two of these cases viral RNA but not antigen was detected in the spinal cord. In long duration cases (>36 months) viral RNA was abundant in all areas of the CNS examined, frequently in the absence of demonstrable antigen. These findings may suggest viral spread in a cephalo-caudal direction, probably by transneuronal spread.

The expression of the endothelial cell antigen CD34 in demyelinating disease

In this study, the antigenic expression of CD34, a 110 kDa glycoprotein which is expressed on human haemopoietic progenitor cells and vascular endothelium, has been assessed in a variety of neuropathological conditions, including infectious and demyelinating disease. Using immunoperoxidase staining on paraffin sections, the immunohistochemical results show that CD34 antigen is expressed widely on human CNS endothelium in grey and white matter, in the eye including retina, and in the anterior and posterior lobes of the pituitary. In demyelinating disease CD34 antigen expression was not detected in acute lesions, whereas strong expression was observed in old lesions. CD34 endothelial positivity was observed in areas of gliosis, vasogenic oedema, vascular disease and in Alzheimer's and Parkinson's disease pathology. A general pattern emerged, with CD34 antigen reactivity predominantly negative in areas of inflammation with demyelination but positive in adjacent non-inflamed tissue, irrespective of myelin pathology. We conclude that perivascular inflammation is a key factor in the absence of immunoreactivity of CD34 in the CNS in demyelinating disease.

An immunohistochemical study of neurofibrillary tangle formation in post-encephalitic Parkinsonism

Neurofibrillary tangle (NFT) formation is a feature of postencephalitic Parkinsonism (PEP) and Alzheimer's disease (AD). Tangle formation has been compared immunohistochemically in these 2 conditions. Staining patterns for tau protein, ubiquitin and beta/A4 amyloid protein were studied in frontal lobe, hippocampus, and midbrain in 2 classical cases of PEP, 2 cases of AD and 2 controls matched for age and sex. NFTs were present in all cases, but with varying frequency: all tangles were tau-positive and many were ubiquitinated. In the frontal cortex and hippocampus, irrespective of the case category, tangle formation was associated with beta/A4 amyloid deposition. A similar association was present in the 2 AD cases in the midbrain. However, in PEP tangle formation in the midbrain was not associated with adjacent beta/A4 amyloid deposition. This finding raises the possibility that the pathogenetic mechanism of tangle formation in PEP is different from that of AD, although the final cellular morphological expression of abnormality in both conditions is similar.

Adhesion molecule expression and lymphocyte adhesion to cerebral endothelium: effects of measles virus and herpes simplex 1 virus

Expression of endothelial cell (EC) adhesion molecules is increased in inflammatory neurological disorders and this may regulate lymphocyte homing to the central nervous system (CNS). Viral encephalitis is characterised by lymphocytic infiltration of the CNS and one mechanism of this response may be EC adhesion molecule induction with consequent inflammatory cell/EC binding. This report characterises the effects of herpes simplex 1 (HSV1) or measles virus (MV) infection of BALB/c brain microvascular EC in vitro on adhesion of naive syngenic splenocytes and levels of ICAM-1. Adhesion was enhanced by 42% for MV-infected cells and by 73% for HSV-1-infected EC. At the multiplicities of infection employed, levels of ICAM-1 were upregulated on HSV-1-infected EC, but not on MV-infected EC. It is concluded that ICAM-1/ligand interactions do not play a role in mediation of MV enhancement of adherence, but represent one mechanism responsible for increased lymphocyte adherence to HSV-1-infected cerebral EC.

Desmin myopathy with cardiomyopathy

We report a case of abnormal desmin accumulation within the muscle of a 30-year-old female with a 2-year history of cardiomyopathy and axial muscle weakness. Serum creatine kinase was normal. A quadriceps muscle biopsy revealed pink hyaline inclusions, which stained for acid phosphatase and with PAS and were present in both fibre types. Electron microscopy showed these inclusions to consist of aggregates of irregularly arranged 6- to 15-nm-diameter filaments enmeshed within a central core of dense granulo-amorphous material. In other areas, the granulo-amorphous material lay as irregular patches within the sarcoplasm, mainly at the level of the "Z" band causing disruption of the sarcomere. Immunoelectron microscopy using colloidal gold showed that the dense amorphous material reacted strongly with desmin antisera and could, therefore, represent a defective or phosphorylated form of the protein.

Association of measles virus with neurofibrillary tangles in subacute sclerosing panencephalitis: a combined in situ hybridization and immunocytochemical investigation

Neurofibrillary tangle formation, a cardinal characteristic of Alzheimer's disease, is also a feature of several other neurodegenerative disorders, including subacute sclerosing panencephalitis (SSPE). In the present study the association of measles virus genome with neurofibrillary tangle formation has been studied in five cases of SSPE, using in situ hybridization (measles genome) and immunocytochemistry (tau, ubiquitin and beta/A4 amyloid). In two cases with duration of disease less than one year, neurofibrillary tangle formation was not observed. However, in those cases in which the disease was of several years duration, numerous tau- and ubiquitin-positive neurofibrillary tangles were demonstrated. In the two cases of longest duration, double-labelling techniques demonstrated the frequent association of neurofibrillary tangle formation with neuronal measles virus genome positivity. Immunocytochemistry for beta/A4 amyloid failed to demonstrate amyloid in any of the five cases. These findings support the hypothesis that neurofibrillary tangle formation can occur independently of amyloid formation and that this mechanism may operate in both Alzheimer's disease and in virally-induced disease.

Progressive neuronal degeneration of childhood (Alpers syndrome) with hepatic cirrhosis

Four children, from two families, suffered from fatal degeneration of the cerebral grey matter. Their disease was characterised by intractable epilepsy, epilepsia partialis continua, progressive deterioration, and terminal hepatic dysfunction. EEG showed marked and distinctive slow wave abnormality, visual evoked responses were diminished, and cerebral atrophy was seen on CT scan. Pathological findings were of neuronal loss and hepatic cirrhosis. The combination of cerebral degeneration, hepatic disease and familial occurrence suggests an inborn error of metabolism with autosomal recessive inheritance. The features described are those of Alpers syndrome, especially the recently delineated subgroup with progressive neuronal degeneration and liver disease.

Measles virus infection of cells in perivascular infiltrates in the brain in subacute sclerosing panencephalitis: confirmation by non-radioactive in situ hybridization, immunocytochemistry and electron microscopy

As part of continuing multidisciplinary studies on the neuropathogenesis of subacute sclerosing panencephalitis (SSPE), in situ hybridisation, immunocytochemistry and electron microscopy were used to detect measles virus nucleic acid, protein and nucleocapsids in brain perivascular infiltrates of three cases. Perivascular cuffing cells which contained measles virus nucleic acid and antigens were found in all cases. Infected cuffs occurred predominantly in areas of general parenchymal cell infection and in many of these a high proportion of the infiltrating cells were infected. Other cuffs in these areas were either uninfected or contained only a few infected cells. Occasional infected cells were also seen in cuffs in non-infected areas. In contrast, no specific immunocytochemical reactions or in situ hybridisation for measles virus was observed in brain tissue from a patient with herpes encephalitis. By electron microscopy viral nucleocapsid, consistent with measles virus, was found within the cytoplasm of plasma cells in the inflammatory cuffs in SSPE brain tissue. Possible explanations for our results are that infiltrates become infected on arrival in the CNS or alternatively, that the infected infiltrates reflect a generalised infection of the reticuloendothelial system. The frequent presence of uninfected cuffs favours the former explanation.

Dominantly inherited tubular aggregate myopathy

We report an unusual familial myopathy characterized morphologically by the presence of large tubular aggregates in all fibre types. Two patients, a father and daughter, presented with slowly progressive proximal weakness, limitation of eye movement, and Achilles tendon contractures. Serum creatine kinase was 5-10 times normal. Light microscopy revealed type I fibre predominance. Basophilic accumulations, which stained intensely with the NADH-TR reaction, were present in both fibre types. Electron microscopy revealed that these consisted of tightly packed parallel tubular arrays. These varied somewhat in their ultrastructural appearance and were classified accordingly as type I, II, and III tubular structures. The tubular aggregates appear to be derived from the sarcoplasmic reticulum. This report further supports the evidence of a distinct clinico-pathological entity of genetic origin.

Central pontine myelinolysis without hyponatraemia

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Cerebral endothelial cell infection by measles virus in subacute sclerosing panencephalitis: ultrastructural and in situ hybridization evidence

Infection of vascular endothelium plays a central role in the pathogenesis of acute measles virus infection outside the central nervous system (CNS) but has not been described in the human CNS. An ultrastructural survey was made of blood vessels in five cases of subacute sclerosing panencephalitis (SSPE) to determine whether or not infection of cerebral vascular endothelium occurred in this persistent fatal CNS disease caused by measles virus. Morbillivirus nucleocapsids were found in a few endothelial cells in three necropsy cases but not in the limited tissue available from two biopsies. In a severe parenchymal lesion in one necropsied case, endothelial cells hybridized in situ with a biotinylated probe specific for the N genomic RNA of measles virus. It is concluded that human cerebral endothelium is susceptible to measles virus infection.

Neurotoxicity of 1-methoxycycloheptatriene--a Purkinje cell toxicant

The toxicity of 1-methoxycycloheptatriene (1-MCHT), a sensory irritant, has been investigated in beagles. It was found to produce gross inco-ordination of the limbs at intravenous doses greater than 10 mg kg-1. The main histological abnormalities were in the cerebellum and consisted of Purkinje cell death and subsequent reactive gliosis. A few necrotic neurons were seen in the diencephalon, pons and medulla. Haematological abnormalities, e.g. leucocytosis with relative lymphopenia, were seen, while biochemical changes included hyperglycaemia and a rise in plasma aminotransferases. The no-effect dose for the histological and biochemical changes was the same. These abnormalities are compared with cerebellar changes observed in acrylamide and other toxic states.

Comparison of reporter molecules for viral in situ hybridization

A number of streptavidin-linked reporter molecules at the endpoint of a five-step detection protocol for viral in situ hybridization using biotinylated probes were examined. DNA-DNA and RNA-RNA model systems were used. Streptavidin linked to either peroxidase or fluorescein was found to be optimal in terms of sensitivity and resolution within individual cells. All other reporter molecules labelled similar numbers of cells with low background reaction. However, streptavidin-5 nm gold followed by silver enhancement gave very high background staining making interpretation of positive signals very difficult.

A study of glutamine synthetase in normal human brain and intracranial tumours

Glutamine synthetase (GS) activity was measured in selected areas of three normal brains and in 262 biopsies from patients with suspected intracranial tumours. In general, levels were higher in grey matter than in white matter and the highest activities of all were found in the hypothalamus which is consistent with its high glutamatergic activity. In the biopsy material, GS activity was greatest in gliotic brain, in keeping with the predominantly astrocytic localization of the enzyme. High levels were also found in astrocytomas and oligodendrogliomas but there was considerable variation between tumours, suggesting a random loss of GS expression during neoplastic transformation or heterogeneity in their cellular origin. The immunocytochemical demonstration of GS in neoplastic oligodendrocytes and in meningioma cells argues against absolute cell-type specificity for this enzyme.

Use of immunocytochemistry and biotinylated in situ hybridisation for detecting measles virus in central nervous system tissue

Optimised immunocytochemical (ICC) and in situ hybridisation (ISH) protocols for long term, formalin fixed, central nervous system tissue infected with measles virus were developed. The effectiveness of 10 proteases for the enzymatic unmasking of formalin fixed antigen and nucleic acid was investigated. Protease VIII gave maximal signal generation with optimal tissue preservation and no background staining for both techniques. The use of a microwave oven as an additional pre-hybridisation step for RNA-RNA in situ hybridisation produced a significant increase in the number of cells labelled for genomic RNA. The ability to show the presence of antigen and nucleic acid in long term, formalin fixed tissue facilitates the use of stored necropsy material available in pathology departments for ICC and ISH investigations.

Examination of eight cases of multiple sclerosis and 56 neurological and non-neurological controls for genomic sequences of measles virus, canine distemper virus, simian virus 5 and rubella virus

In situ hybridization studies have been carried out on brain samples from eight cases of multiple sclerosis (MS) and 56 non-neurological and neurological controls, using single-stranded 35S-labelled RNA probes prepared against genomic RNA sequences of measles virus, canine distemper virus, rubella virus and simian virus 5. Foci of hybridization were found using probes against the measles virus nucleocapsid protein (N), phosphoprotein and fusion protein gene sequences in two of the MS cases, and also in one control, a case of disseminated cytomegalovirus infection with spinal cord necrosis. This result was confirmed using biotinylated probes prepared against the measles virus N genomic sequence. No hybridization was found in any of the MS or control cases using any of the other viral genome-specific probes.

Growth hormone treatment in adults with growth hormone deficiency: effect on muscle fibre size and proportions

The effect of a 6-month period of substitution therapy with recombinant human growth hormone (rhGH) on muscle fibre size and muscle fibre type proportions has been investigated in a group of 13 adults with growth hormone deficiency. All had a peak growth hormone (GH) response to insulin-induced hypoglycaemia of less than 7 mU/l. There was no statistically significant change in the lesser fibre diameter or fibre proportions of either type 1 or type 2 muscle fibres in the rhGH group, as compared with placebo.

Antibodies to simian virus 5 in patients with multiple sclerosis and other neurological disorders

Antibodies to the paramyxovirus simian virus 5 were measured in cerebrospinal fluid samples using an enzyme-linked immunosorbent assay. Six of the 13 clinically definite MS patients had elevated levels of antibodies compared with other neurological disease and orthopaedic controls. None of the samples from MS patients classed as probable or possible had increased amounts of SV5 antibodies. Simian virus 5 antibodies and measles antibodies showed a weak correlation and it is suggested that the elevated levels of the former are a manifestation of the increased antiviral response found in some MS patients.

Transmissible agent in the amyotrophic form of Creutzfeldt-Jakob disease

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Primary malignant melanoma of the meninges

A case of primary malignant melanoma of the meninges is described in which the clinical presentation is that of visual loss and limb weakness. Clinically a diagnosis of carcinomatous meningitis was made and subsequently malignant cells were found in the cerebrospinal fluid (CSF). At autopsy the diagnosis of primary malignant melanoma of the meninges was made.

Screening of multiple sclerosis cerebrospinal fluid for autoantibodies

An enzyme-linked immunoadsorbent assay, using nitrocellulose discs as solid phase and small sample volumes (50 microliter), was developed for the measurement of antibodies. This was used to screen CSF samples for autoantibodies against tissue components. Extracts from a selection of tissues from both "normal" and MS patients and from 3 glial cell lines were made in phosphate-buffered saline; in the case of neural and lymphoid samples the remaining particulate materials were subsequently solubilised with octylglucoside. The saline-soluble components were screened against CSF samples from MS patients (18), patients with other neurological disorders (10), and matched orthopaedic patients but no differences were found among the 3 groups. However, when the detergent-soluble components were screened a significant (at the P less than or equal to 0.01 level) elevation of reactivity towards brain was found in 6/16 MS patients and 2/12 patients with other neurological diseases when compared to their controls.

Neuropathology and neurovirulence of canine distemper virus plaque isolates in the hamster

The relationship between neuropathological abnormalities, antibody response and neurovirulence of plaque isolates has been studied in an experimental model of canine distemper in the hamster. Genetic virus variance influenced neurovirulence and the experimental evidence supports the hypothesis that the mechanism of this effect may be through the modulating effect of circulating antibody. Large plaque virus (LPV) produced severe encephalitis with little early antibody response and a high degree of pathological abnormality. Small plaque virus (SPV) produced mild chronic encephalitis and early antibody response. Microscopically, histological abnormalities in this group were qualitatively similar to those seen with LPV but generally of lesser degree. Immunosuppression in SPV infected animals increased the severity of the encephalitis, reflected by the increase in inflammation and inclusion formation. Combined SPV and LPV infection produced high antibody levels and less severe disease than LPV infection alone with an intermediate pattern of histological abnormality.

Possible Stewart's nasal granuloma with dissemination to meninges, peripheral nerves and muscle and renal glomerular IgA deposition

A case of Stewart type, non-healing nasal granuloma complicated by dissemination to meninges, peripheral nerve and muscle is described. The deposition of IgA in renal glomeruli in this condition is documented and the significance of this finding is discussed.

Experimental penetrating head injury: some aspects of light microscopical and ultrastructural abnormalities

A high velocity model of penetrating head injury has been developed in the rhesus monkey and a lower velocity model in the baboon. It is apparent that pathological changes are widespread and develop early although the pathogenesis of the diffuse vascular changes is unknown. The present study involved the sampling of grey and white matter from 20 monkeys with high velocity injury, and 10 baboons with low velocity injury together with similar material from a number of normal control animals. 30 minutes after a high velocity injury swelling of perivascular astrocytes was present, sometimes associated with an increase in extracellular fluid. Animals with lower velocity injuries survived for some hours. Astrocytic swelling and perivascular oedema associated with cellular necrosis was frequently found in this group. The pathogenesis of these lesions is discussed.

An ultrastructural study of experimental high velocity penetrating head injury

Experimental high velocity missile brain injury in the rhesus monkey produces widespread swelling of perivascular astrocytes within 30 min of injury. Possible mechanisms for this lesion include a direct effect of force, chemical mediation secondary to the extravasation of blood, alterations in the permeability of the blood brain barrier and ischaemia. The implications of this findings for the function of the blood brain barrier, for neurotransmission and for neuronal survival are discussed.

Experimental high-velocity missile head injury

A standardized experimental high-velocity penetrating head-injury model has been produced in which pathological lesions were observed, not only in the wound track but at sites more remote from the track in the hypothalamus, brain stem and cerebellum. Diffuse subarachnoid haemorrhage was common and intraventricular haemorrhage was a constant feature. Other constant histological abnormalities were:L 1. Perivascular "ring' haemorrhages. 2. Perivascular haemorrhage with a surrounding zone of decreased staining intensity. 3. Perivascular increased staining intensity. 4. Areas of decreased staining intensity apparently dissociated from areas of haemorrhage. The pathogenesis of the perivascular lesions is discussed and preliminary studies suggest that these may be the site of early oedema. The implications of this experiment for military surgery and for ballistic protection of the head are discussed.

The isolation of large and small plaque canine distemper viruses which differ in their neurovirulence for hamsters

Large and small plaque-forming viruses were isolated from the Onderstepoort strain of canine distemper virus (CDV). Small plaque virus, which was released more slowly from infected cells than large plaque virus, readily established persistent infections in Vero cells, whereas large plaque virus required undilute passage to do so. All persistently infected cultures eventually released small plaque virus. No difference was found in the size of polypeptides induced by either plaque-purified viruses or virus released from persistent cultures. Both dilute and undilute passage, large plaque virus produced an acute neurological illness in weanling hamsters. whereas small plaque virus failed to produce any clinical signs of disease for 3 months after inoculation. After this period 50% of the animals infected with small plaque virus showed a general deterioration in their condition and lesions were observed in the brain which resembled those found in cases of large plaque virus infection. Serum-neutralizing antibody titres to CDV rapidly increased after infection with small plaque virus, whereas animals infected with large plaque virus had low or undetectable levels. All hamsters infected with small plaque virus and a small number which survived large plaque virus infection had elevated titres of antibody over a test period of 15 months.

Abnormalities in the macroscopically normal white matter in cases of mild or spinal multiple sclerosis (MS)

In a study of a series of mild and spinal varieties of multiple sclerosis the following histological changes have been found in the macroscopically normal white matter: 1. Marked astrocytic proliferation. 2. Some sclerosis of blood vessels. 3. Some perivascular inflammation. 4. Occasional unsuspected demyelination.

Tubular aggregates in murine dystrophy heterozygotes

Heterozygous dystrophic mice (strain 129 ReJ dy/+) were studied to determine the morphological changes that are characteristic of the heterozygote state. The morphology of the muscle in 35 heterozygotes (+/?) was compared with that of 35 homozygotes (dy/dy) and 20 normal controls (+/+). Muscle was examined with light microscopy, standard histochemical techniques, and electron microscopy. Few abnormalities were detected with light microscopy or with histochemistry. With electron microscopy, some slight nonspecific evidence of muscle damage in the form of focal myofibrillar degeneration was seen in all of the heterozygotes. The striking abnormality, however, was the presence of tubular aggregates in type 2 fibers in 60% of the heterozygotes. Tubular aggregates were not found in homozygous dystrophic mice or in normal controls. The significance of this finding is discussed and it is suggested that tubular aggregates may represent lateral sac dilatation and infolding.

The fragility of cerebral lysosomes in multiple sclerosis

The possibility that cerebral lysosomes in the white matter from patients with multiple sclerosis (MS) are more fragile than in normal controls was investigated in tissue obtained at necropsy. In the MS cases no differences were found in results from samples obtained from histologically distinct areas of white matter, i.e. plaque, periplaque and macroscopically normal white matter. However, in comparison to white matter from a group of controls, certain differences were found. Firstly, the cerebral lysosomes in MS white matter appeared to be more fragile than those in the control cases. Secondly, the remaining intact lysosomes in MS cases showed different characteristics from those obtained in control cases. These results, in the light of earlier experiments in rat brain, were interpreted as further evidence of a greater fragility in the cerebral lysosomes from MS cases. The implications of these results in relation to current thinking on the aetiology of MS are discussed.

Systemic lupus erythematosus clinically resembling multiple sclerosis and with unusual pathological and ultrastructural features

A case of systemic lupus erythematosus is described which clinically resembled multiple sclerosis and in which the lesions were restricted to the central nervous system. The necropsy findings of vascular thickening and necrosis in the spinal cord and in a posterior nerve root explain the main clinical abnormalities. Clinical signs of the terminal peritonitis secondary to cholecystitis were absent or minimised probably because of the steroid therapy and spinal cord necrosis. Primary demyelination was not demonstrated though electronmicroscopy revealed lattice fibrillar inclusions within a few myelin sheaths. An unusual ultrastructural feature was the finding of "rod-shaped tubular bodies" in large numbers in the endothelial cells of cerebral blood vessels. The incidence and morphology of these organelles are compared with those of the intracisternal tubuloreticular structures (TRS) commonly found in systemic lupus erythematosus.

The cellular origin of lysosomal enzymes in the plaque in multiple sclerosis. II. A histochemical study with combined demonstration of myelin and acid phosphatase

Existing techniques have been adapted and it has been possible to demonstrate acid phosphatase (APP) and myelin, lipid or astrocytic fibres in the same histological section. In normal controls APP was demonstrated in neurons, astrocytes, ependyma including choroid plexus epithelium and in pericytes, but not in oligodendrocytes. In multiple sclerosis (MS), APP positive cells were found in the plaque, plaque edge and macroscopically normal white matter. Contrary to some previous reports, not only macrophages, but also astrocytes in the MS plaque were found to be APP positive, although the distribution of enzyme in these cells was predominantly diffuse, unlike the particulate distribution in normal astrocytes and other APP positive cells: the significance of this finding is discussed. It is concluded that astrocytes and macrophages are the main source of the elevated levels of APP found biochemically in MS and that in old plaques astrocytes make the major contribution.