STochastic Optical Reconstruction Microscopy (STORM) reveals the nanoscale organization of pathological aggregates in human brain

AIMS

Histological analysis of brain tissue samples provides valuable information about the pathological processes leading to common neurodegenerative disorders. In this context, the development of novel high-resolution imaging approaches is a current challenge in neuroscience.

METHODS

To this end, we used a recent super-resolution imaging technique called STochastic Optical Reconstruction Microscopy (STORM) to analyse human brain sections. We combined STORM cell imaging protocols with neuropathological techniques to image cryopreserved brain samples from control subjects and patients with neurodegenerative diseases.

RESULTS

This approach allowed us to perform 2D-, 3D- and two-colour-STORM in neocortex, white matter and brainstem samples. STORM proved to be particularly effective at visualizing the organization of dense protein inclusions and we imaged with a <50 nm resolution pathological aggregates within the central nervous system of patients with Alzheimer's disease, Parkinson's disease, Lewy body dementia and fronto-temporal lobar degeneration. Aggregated Aβ branches appeared reticulated and cross-linked in the extracellular matrix, with widths from 60 to 240 nm. Intraneuronal Tau and TDP-43 inclusions were denser, with a honeycomb pattern in the soma and a filamentous organization in the axons. Finally, STORM imaging of α-synuclein pathology revealed the internal organization of Lewy bodies that could not be observed by conventional fluorescence microscopy.

CONCLUSIONS

STORM imaging of human brain samples opens further gates to a more comprehensive understanding of common neurological disorders. The convenience of this technique should open a straightforward extension of its application for super-resolution imaging of the human brain, with promising avenues to current challenges in neuroscience.

Role of physicians' reactance in e-iatrogenesis: a case study with ASTI guiding mode on the management of hypertension

Clinical decision support systems (CDSSs) have the potential to increase guideline adherence, but factors of success are not yet understood. ASTI guiding mode (ASTI-GM) is an on-demand guideline-based CDSS where the user navigates in a knowledge base to get the best treatment for a given patient. We conducted a web-based evaluation of ASTI-GM, carried out as a before-after study, where general practitioners (GPs) were asked to solve 5 clinical cases, first without ASTI-GM, then using the system. Of the 136 GPs that resolved the case on the management of hypertension, compliance with best practices increased from 69.1% to 80.9% with ASTI-GM. When the navigation matched the set of patient parameters described in the clinical case, the increase was even higher and reached 92.9%. E-iatrogenesis has been measured at 19.1%, with 5.1% of commission errors, 8.1% of negative reactance, and 5.9% of neutral reactance. Role of physicians' reactance in noncompliance with guideline-based CDSSs should be further investigated.

Why GPs do not follow computerized guidelines: an attempt of explanation involving usability with ASTI guiding mode

Clinical decision support systems (CDSSs) have the potential to increase guideline adherence, but factors of success are not well understood. ASTI-GM is an on demand guideline-based CDSS where the user interactively characterizes her patient by browsing the system knowledge base to obtain the recommended treatment. We conducted a web-based evaluation of ASTI-GM as a before-after study to assess whether the system improves general practitioners' (GPs) performance and how they would use it. Five clinical cases had to be solved, as usual in the before phase, and using ASTI-GM in the after phase. On a 2-month period, 266 GPs participated and 1,981 prescription orders were collected. The overall guideline adherence rate increased from 27.2% to 64.3%. Only 56.4% of ASTI-GM uses corresponded to a "good use" of the system. Adherence increased from 28.5% to 86.1% in the sub-group of "good uses", whereas it only increased from 28.1% to 36.6% in the complementary sub-group. Reasons for non "good uses" of CDSSs should be investigated since they impede their potential impact.

Consequences of the verification of completeness in clinical practice guideline modeling: a theoretical and empirical study with hypertension

Building clinical decision support systems requires a formalization of clinical practice guidelines (CPGs) including the verification of completeness to ensure all medically relevant situations are addressed. Recommendations that rely on completed knowledge cannot be but expert-based. Using French hypertension management guidelines, we characterized the status of a patient profile as evidence-based (EB), consensus-based (CB), or expert-based (XB). The distribution of these status on the formal patient profiles of ASTIGM knowledge base showed that 12.6% (0.5% EB and 12.1% CB) lead to explicit CPG recommendations. The same analysis on a sample of 435 actual patients medical records showed that 55% were covered by CPGs. The characterization of guideline-based CDSSs should be based on empirical data estimated from the target population of CPGs.

Clinical features of fatal familial insomnia: phenotypic variability in relation to a polymorphism at codon 129 of the prion protein gene

Fatal Familial Insomnia is a hereditary prion disease characterized by a mutation at codon 178 of the prion protein gene cosegregating with the methionine polymorphism at codon 129 of the mutated allele. It is characterized by disturbances of the wake-sleep cycle, dysautonomia and somatomotor manifestations (myoclonus, ataxia, dysarthria, spasticity). PET studies disclose severe thalamic and additionally cortical hypometabolism. Neuropathology shows marked neuronal loss and gliosis in the thalamus, especially the medio-dorsal and anterior-ventral nuclei, olivary hypertrophy and some spongiosis of the cerebral cortex. Detailed analysis of 14 cases from 5 unrelated families showed that patients ran either a short (9.1 +/- 1.1 months) or a prolonged (30.8 +/- 21.3 months) clinical course according to whether they were homozygote met/met or heterozygote met/val at codon 129. Moreover, homozygotes had more prominent oneiric episodes, insomnia and dysautonomia at onset, whereas heterozygotes showed ataxia and dysarthria at onset, earlier sphincter loss and epileptic Grand Mal seizures; they also displayed more extensive cortical involvement on PET and at postmortem examination. Our data suggest that the phenotype expression of Fatal Familial Insomnia is related, at least partly, to the polymorphism at codon 129 of the prion protein-gene.

[Do beta-blockers prevent coronary events in hypertensive patients?]

Beta-blockers have been considered for decades as effective agents in preventing coronary events in hypertensive patients. Actually, the scrutiny of the available data arises some doubts over the real value of this pharmacological class. In primary prevention, the clinical benefits of beta-blockers are poorly documented: the studies conducted against placebo (MRC, IPPPSH...) did not show any significant differences regarding the rate of coronary events (except within non smokers); moreover, the beneficial effect of propranolol in preventing sudden deaths and silent myocardial infarctions has been reported byjust one retrospective analysis. Likewise in HAPPHY study, the comparison with diuretics did not emphasize a clear superiority of one of both classes; the better effect of metoprolol regarding overall mortality and fatal coronary events was shown in the pecular subset MAPHY, only. Furthermore, in elderly people, HEP, MRC OA and STOP studies did not find any significant effect of beta-blockers in preventing coronary events, as compared with placebo. However, SHEP study, which involved patients older than 60 years with isolated systolic hypertension receiving first a diuretic, then a beta-blocker(atenolol) in 1/4 of the cases, demonstrated a significant reduction versus placebo both in strokes and in coronary events. Finally, in UKPDS, CAPP, LIFE and CONVINCE studies, atenolol turned out to have a similar efficacy as captopril, losartan and verapamil, in preventing ischemic heart disease. Among the numerous published meta-analyses, that of Psaty pointed out the absence of a primary cardioprotective effect by beta-blockers; more recently, that of Carlberg, emphasized atenolol given alone as the first-line drug to fail in significantly reducing coronary events and strokes. In secondary prevention, some more convincing data may be found in the literature, regarding post myocardial infarction patients (meta-analyses of Staessen, 1982, Yusuf, 1985 and Soriano, 1997), as well as those with stable angina (BIP study in diabetics) or silent ischemia (ASIST study: significant reduction in number and duration of ischemic events by atenolol). Moreover, INVEST study recently showed atenolol and verapamil to have an equivalent efficacy in the hypertensive patients with stable coronary artery disease. Last, hypertension should be reminded as resulting in many cases of heart failure, a pathology where beta-blockers have clearly demonstrated their beneficial effects.

[Left ventricular hypertrophy in hypertensive patients. Epidemiology and prognosis]

The aim of this review is to analyze the epidemiology and prognosis of left ventricular hypertrophy (LVH) in hypertensive patients through literature data and to identify clinical factors contributing to its development. After an exhaustive review of literature through Medline database, eighteen studies (including 8 European ones) have been selected. The prevalence of LVH diagnosed by EKG (7 studies) is steadily over 15%. It can reach 50% in some subgroups of the Framingham study. Among 11 studies using echocardiography as diagnostic tool, the prevalence varies from 14 to 44% (Bordeaux cohort). In the Framingham study, 32% of men and 45% of women over 60 years presented an echography-defined LVH. The variations observed in different studies may be explained by differences on the modes of enrollment and diagnosis. The clinical factors associated with the occurrence of LVH are age, which can be confounded with the duration of presence of hypertension, the severity and lack of therapeutic management of hypertension. Thirteen studies permitted to quantify the cardiovascular risk related to hypertension. In hypertensive patients, the presence of EKG-LVH or the one observed by echocardiography would correspond to a two-fold increase of cardiovascular mortality and morbidity. Moreover, a cardiovascular risk gradient is observed according to the LVH geometry (concentric remodeling, followed by eccentric LVH and concentric LVH). Three studies including the Framingham study demonstrated that LVH is a major risk factor of stroke. This exhaustive literature review stresses on the high prevalence and the severity of LVH during hypertension. Its diagnosis allows to identify high cardiovascular risk patients suffering from hypertension. It emphasizes on the importance of an early and careful therapeutic management of hypertension.

Sporadic late onset paroxysmal cerebellar ataxia in four unrelated patients: a new disease?

We describe a peculiar form of late onset paroxysmal cerebellar ataxia including clinical features similar to episodic ataxia type 2 (EA2) but unresponsive to acetazolamide. Four unrelated patients were clinically investigated. Neuropathological examination was performed in one patient and molecular analysis in all four. All 47 exons of CACNA1A were screened by a combination of single-strand conformer polymorphism and sequencing analysis in three patients. In addition, the length of the CAG repeat was determined in all four patients. The four patients were in their 60s at the onset of the disease, which was characterized by cerebellar ataxia attacks lasting from a few minutes to 1-2 h and occurring mainly in the morning. In the interictal period a nystagmus was present together with a slowly progressive cerebellar ataxia over the years. The neuropathological examination disclosed a dramatic loss of Purkinje cells mainly in the vermis. Moreover, certain cerebellar granular neurons had a strong cytoplasmic staining at immunopathological examination with an anti-tau protein serum. Search for truncating mutations or CAG repeat expansion in CACNA1A was negative. This late-onset paroxysmal cerebellar ataxia with neuropathological lesions restricted to Purkinje cells and with negative results both for truncating mutations and CAG expansion in the CACNA1A gene represents a new entity. Further studies are needed to delineate the underlying process.

Chronic inflammatory demyelinating polyneuropathy: immunopathological and ultrastructural study of peripheral nerve biopsy in 42 cases

The authors recently reexamined the peripheral nerve biopsies from 42 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). There were 27 males and 15 females, aged from 9 to 84 years, and 13 had relapses. No patient had vasculitis, monoclonal gammopathy, tumor, diabetes mellitus, Lyme disease, familial neuropathy, HIV, or any other immune deficiency. In the endoneurium, perivascular inflammatory cell infiltrates were present in only one case, but scattered histiocytes marked by KP1 on paraffin-embedded fragments were present in every case and there were no T-lymphocytes. At ultrastructural examination macrophage-associated demyelination was observed in 17 cases, of which 6 had relapses separated by intervals of several months or years. Axonal lesions without associated primary demyelination were observed in 4 cases and 3 of these had relapses. Thirty-two patients had mixed lesions of demyelination and axonal involvement. This study confirms other recent data indicating that in all cases of CIDP, macrophages are present in the endoneurium. Macrophage-associated demyelination is the characteristic feature of demyelinating forms. On the other hand, isolated primary axonal forms, which have been known since 1989, are relatively frequent and prone to relapses.

Peripheral neuropathy associated with monoclonal IgG of undetermined significance: clinical, electrophysiologic, pathologic and therapeutic study of 14 cases

Fourteen patients with peripheral neuropathy and monoclonal IgG of undetermined significance are reported with a retrospective study of the clinical features, electrophysiologic and sural nerve biopsy findings. There were two groups. Five patients had a relapsing chronic sensorimotor polyneuropathy with clinical (5/5), electrophysiologic (4/5) and pathologic (5/5) features compatible with chronic inflammatory demyelinating polyneuropathies (CIDP). The nine others had a slowly progressive sensory (5/9) (SPNP) or sensorimotor (4/9) (SMPNP) axonal polyneuropathy. Four patients of the first group were treated with intravenous human immunoglobulin (400 mg/kg/day for five days) with significant clinical improvement. The motor conduction velocities and distal latencies of two of these patients improved following treatment, thus matching the clinical improvement. Our results on peripheral nerve biopsies confirm the differentiation of patients with CIDP from those with SMPNP and SPNP. There was no specific immunologic serologic reactivity in any of the cases.

Congenital insensitivity to pain with anhydrosis. Report of two unrelated cases

Two unrelated female cases of congenital insensitivity to pain with anhydrosis are presented. The first case was born from consanguineous parents. In both cases, onset of manifestation was observed in infancy with automutilation and recurrent fever. Both were mentally retarded. They underwent a peripheral nerve biopsy respectively at 3 and 33 years. A dramatic loss of unmyelinated fibers was observed in both cases. Myelinated fibers were also moderately reduced in number, especially those of smallest diameter; this loss was more marked in the second patient who was adult when the peripheral nerve was studied. Clusters of regenerating myelinated fibers were seen in both cases. Such histological observations might suggest a slowly progressive disorder. The cases are discussed together with previous reports dealing with congenital insensitivity to pain.

Chronic inflammatory demyelinating polyneuropathy caused by HIV infection in a patient with asymptomatic CMT 1A

It is well known that patients with Charcot-Marie-Tooth (CMT) disease are liable to present with episodes of cortisone-responsive demyelination, and a superimposed inflammatory component has been suggested. We report a patient who presented with a chronic inflammatory demyelinating polyneuropathy due to a recent HIV infection, which revealed a previously asymptomatic CMT 1A disease documented by identification of the characteristic duplication on the p11.2 region of chromosome 17. The inflammatory process was characterized by pathologic findings on a superficial peroneal nerve biopsy, and the patient improved significantly after corticotherapy. This report gives support to the hypothesis of a genetic susceptibility to inflammatory demyelinating processes in certain CMT kindreds.

Chronic inflammatory demyelinating polyneuropathy associated with dysglobulinemia: a peripheral nerve biopsy study in 18 cases

The possible occurrence of chronic inflammatory demyelinating polyneuropathy (CIDP) in association with an identified dysglobulinemic status is recognized and a causal relationship between the two has been suggested. We had the opportunity to study 18 patients presenting with CIDP and dysglobulinemia. This was an IgG monoclonal gammopathy (IgG MG) in 8 cases, an IgM monoclonal gammopathy (IgM MG) in 8, an IgG-IgM biclonal gammopathy in 1 case and an IgM monoclonal cryoglobulinemia in another. A peripheral nerve biopsy specimen was available for all patients and the morphological findings in these specimens in the cases of CIDP with IgG MG or cryoglobulin did not differ from those without, whereas characteristic features were observed in the cases of CIDP with IgM MG and anti-myelin associated glycoprotein activity.

The neuronal Golgi apparatus is fragmented in transgenic mice expressing a mutant human SOD1, but not in mice expressing the human NF-H gene

Fragmentation of the Golgi apparatus (GA) of motor neurons was first described in sporadic amyotrophic lateral sclerosis (ALS) and later confirmed in transgenic mice expressing the G93A mutation of the gene encoding the enzyme Cu,Zn superoxide dismutase (SOD1(G93A)) found in some cases of familial ALS. In these transgenic mice, however, the fragmentation of the neuronal GA was associated with cytoplasmic and mitochondrial vacuoles not seen in ALS. The present new series of transgenic mice expressing 14-17 trans gene copies of SOD1(G93A), compared to 25 copies in the mice we studied previously, showed consistent fragmentation of the GA of spinal cord motor neurons, axonal swellings, Lewy-like body inclusions in neurons and glia, but none of the cytoplasmic or mitochondrial vacuoles originally reported. Thus, this animal model recapitulates the clinical and most neuropathological findings of sporadic ALS. Neurofilaments (NF) accumulate in axons and, less often, in neuronal perikarya in most cases of sporadic ALS and they have been implicated in its pathogenesis. In order to investigate whether fragmentation of the neuronal GA also occurs in association with accumulation of perikaryal NFs, we studied the organelle in transgenic mice expressing the heavy subunit of human neurofilaments (NF-H) which developed a motor neuronopathy resembling ALS. The neuronal GA of mice expressing NF-H, however, was intact despite massive accumulation of NFs in both perikarya and axons of motor neurons. In contrast, in transgenic mice expressing SOD1(G93A), the GA was fragmented despite the absence of accumulation of perikaryal NFs. These findings suggest that, in transgenic mice with neuronopathies caused by the expression of mutant SOD1(G93A) or the human NF-H, the GA and the perikaryal NFs are independently involved in the pathogenesis. The evidence suggests that the GA plays a central role in the pathogenesis of the vast majority of sporadic ALS and in FALS with SOD1 mutations.

Peripheral myelin modification in CMT1B correlates with MPZ gene mutations

Morphological modifications were investigated in the peripheral nerve of three unrelated patients with CMT1B. In two patients, molecular genetic analysis showed an Arg98His mutation in the extracellular domain of MPZ, associated with irregularly uncompacted lamellae. This observation confirms previous studies of a well-defined correlation between mutations and morphological phenotypes. In the third patient, a de novo Asp109Asn mutation was associated with abnormally thick myelin sheaths. This adds to the known list of MPZ gene mutations associated with this morphological phenotype.

Prion disease with octapeptide repeat insertion

OBJECTIVE

About 8% of prion disease cases are familial and a few are due to an octapeptide repeat insertion (OPRI) in the prion protein gene. A suitable neuropathological examination has been performed in 20 cases from 9 families and in 3 isolated cases. The number of OPRI ranges from 4 to 9 multiples of 24 base-pair.

METHODS

Results from routine histopathological preparations and from immunohistochemistry performed after special tissue pretreatment were compared with those of molecular genetic investigation.

RESULTS

Eight cases with 4 to 7 multiples of OPRI exhibited characteristic elongated deposits in the cerebellar molecular layer, which were visible on slides prepared with antibodies against the prion protein only. Conversely, 6 cases with 8 or 9 multiples of OPRI presented typical plaques already obvious on routine preparations.

CONCLUSIONS

These variable modifications in the cerebellar molecular layer deserve to be underlined, in particular the elongated deposits which are characteristic for cases presenting 4 to 7 OPRI.

Classification of sporadic Creutzfeldt-Jakob disease based on molecular and phenotypic analysis of 300 subjects

Phenotypic heterogeneity in sporadic Creutzfeldt-Jakob disease (sCJD) is well documented, but there is not yet a systematic classification of the disease variants. In a previous study, we showed that the polymorphic codon 129 of the prion protein gene (PRNP), and two types of protease-resistant prion protein (PrP(Sc)) with distinct physicochemical properties, are major determinants of these variants. To define the full spectrum of variants, we have examined a series of 300 sCJD patients. Clinical features, PRNP genotype, and PrP(Sc) properties were determined in all subjects. In 187, we also studied neuropathological features and immunohistochemical pattern of PrP(Sc) deposition. Seventy percent of subjects showed the classic CJD phenotype, PrP(Sc) type 1, and at least one methionine allele at codon 129; 25% of cases displayed the ataxic and kuru-plaque variants, associated to PrP(Sc) type 2, and valine homozygosity or heterozygosity at codon 129, respectively. Two additional variants, which included a thalamic form of CJD and a phenotype characterized by prominent dementia and cortical pathology, were linked to PrP(Sc) type 2 and methionine homozygosity. Finally, a rare phenotype characterized by progressive dementia was linked to PrP(Sc) type 1 and valine homozygosity. The present data demonstrate the existence of six phenotypic variants of sCJD. The physicochemical properties of PrP(Sc) in conjunction with the PRNP codon 129 genotype largely determine this phenotypic variability, and allow a molecular classification of the disease variants.

Postpolio syndrome: poliovirus persistence is involved in the pathogenesis

The pathogenesis of the postpolio syndrome (PPS) remains unclear. In this study we looked for poliovirus (PV) persistence in the CSF of 20 patients with PPS, in a control group including 20 patients with unrelated neurological diseases, and in 7 patients with stable poliomyelitis sequelae. CSF samples and sera were examined using reverse transcriptase-polymerase chain reaction (RT-PCR) for the detection of PV or other enterovirus genomes; this assay allows the detection from as little as 1 fg viral RNA. Sequencing of amplified products from 5 patients was performed. PV genomic sequences were detected in the CSF of 11 of 20 patients with PPS and in none of the control group. Sequencing in the 5' untranslated region confirmed the presence of mutated PV sequences. These findings suggest that PPS is related to the persistence of PV in the central nervous system.

Recurrence of the T666M calcium channel CACNA1A gene mutation in familial hemiplegic migraine with progressive cerebellar ataxia

Familial hemiplegic migraine (HM) is an autosomal dominant migraine with aura. In 20% of HM families, HM is associated with a mild permanent cerebellar ataxia (PCA). The CACNA1A gene encoding the alpha1A subunit of P/Q-type voltage-gated calcium channels is involved in 50% of unselected HM families and in all families with HM/PCA. Four CACNA1A missense mutations have been identified in HM: two in pure HM and two in HM/PCA. Different CACNA1A mutations have been identified in other autosomal dominant conditions: mutations leading to a truncated protein in episodic ataxia type 2 (EA2), small expansions of a CAG trinucleotide in spinocerebellar ataxia type 6 and also in three families with EA2 features, and, finally, a missense mutation in a single family suffering from episodic ataxia and severe progressive PCA. We screened 16 families and 3 nonfamilial case patients affected by HM/PCA for specific CACNA1A mutations and found nine families and one nonfamilial case with the same T666M mutation, one new mutation (D715E) in one family, and no CAG repeat expansion. Both T666M and D715E substitutions were absent in 12 probands belonging to pure HM families whose disease appears to be linked to CACNA1A. Finally, haplotyping with neighboring markers suggested that T666M arose through recurrent mutational events. These data could indicate that the PCA observed in 20% of HM families results from specific pathophysiologic mechanisms.

Effects of transplantation on the renin angiotensin system (RAS)

Hypertension in organ transplant recipients is associated with several functional modifications of the renin angiotensin system (RAS), which varies according to the type of transplanted organs (kidney, heart, liver or bone marrow) and the immunosuppressive regimen. Before transplantation, chronic organ failure is associated with direct and indirect stimulation of both systemic and local RASs. After transplantation, cyclosporin per se is the major determinant of hypertension. It induces stimulation of both systemic and local RAS via direct and indirect effects within the kidney and peripheral vessels. In kidney transplant recipients, ischaemia from the native kidneys and from the graft, due to acute or chronic rejection, also contributes to RAS stimulation. In cardiac transplant recipients, several haemodynamic parameters, abnormal cardiorenal neuroendocrine reflex mechanism and other hormonal systems (ANF, AVP, catecholamines) stimulate the RAS.

Subacute inflammatory polyneuropathy: two cases with plasmacytoid histiocytes in the endoneurium

Inflammatory polyneuropathies are mainly known by their acute form, Guillain-Barré syndrome, but there are also chronic cases and all are considered as having an autoimmune mechanism. In each form, peripheral nerve biopsies show scattered macrophages in the endoneurium and in certain cases macrophages invade the Schwann cell cytoplasm and destroy the myelin sheath. In rarer cases there is a primary axonal degeneration. The authors studied two chronic cases, which both exhibited mixed primitive axonal and demyelinating lesions, with peculiar histiocytes in the endoneurium. These rounded cells were characteristically well marked by KP1 but showed well-developed rough endoplasmic reticulum cysternae at ultrastructural examination. Such plasmacytoid histiocytes have mainly been studied in subacute lymphadenopathies and have been only briefly illustrated in a few cases of peripheral neuropathies due to Lyme disease or HIV infection. The two cases reported here had no associated diseases and probably correspond to a peculiar subacute autoimmune reaction.

Prion encephalopathy with insertion of octapeptide repeats: the number of repeats determines the type of cerebellar deposits

We studied modifications of the molecular layer of the cerebellum in three patients with octapeptide repeat insertion (OPRI). Two brothers carrying a six-OPRI showed only spongiosis in haematoxylin & eosin preparations (H&E), whereas immunocytochemical examination (ICC) with an antiprion protein (PrP) antibody revealed numerous elongated PrP deposits. The third patient from a family with an eight-OPRI had numerous plaques visible in H&E preparations and had been diagnosed as Gerstmann-Straüssler-Scheinker syndrome. So far, 15 other cases from seven families and three individual cases with OPRI have undergone neuropathological examination. Characteristic PrP deposits were seen in six other cases, two isolated cases with a four- and a seven-OPRI, whereas four cases with a six-OPRI came from three different families. Such deposits have never been reported in other cases of prion encephalopathy, without OPRI. Genuine plaques were observed in five out of the 15 other patients. Interestingly, four had an eight-OPRI and one a nine-OPRI. Cases with OPRI are prone to develop different PrP deposits: those only visible on ICC are not to be confused with genuine plaques visible in H&E preparations. Elongated PrP deposits are present in cases with a four- to seven-OPRI, whereas plaques are present when there is an eight- or a nine-OPRI. All these cases should be termed prion encephalopathy with OPRI.

[Multineuritis in essential hypereosinophilia syndrome]

A 72-old-man with a dramatic weight loss, exhibited a mononeuritis multiplex of subacute onset, and myalgia. There was hypoesthesia and weakness on median and ulnar nerves bilaterally, and weakness on left femoral nerve. Electrodiagnostical studies showed an axonal pattern of neuropathy. There was a considerable hypereosinophilia on blood count without any aetiologia found on exhaustive explorations. The idiopathic hypereosinophilic syndrome with a mononeuritis multiplex was suggested. Histological findings were an acute myelino-axonal degeneration with endoneural oedema, without vasculitis nor eosinophil cell on nerve-biopsy. Dramatic improvement occurred with corticosteroids and immunosuppressive treatment.

Myelin modifications in 8 cases of peripheral neuropathy with Waldenström's macroglobulinemia and anti-MAG activity

Characteristic myelin modifications in patients with IgM monoclonal gammopathy and anti-MAG activity have mainly been studied in cases of undetermined significance, but also exist in cases with indolent Waldenström's macroglobulinemia, i.e., when lymphoplasmocytic infiltration in bone marrow is 15% or more, without any visceral involvement. Since 1983, the authors have examined nerve biopsies from 8 cases with Waldenström's macroglobulinelia by direct immunofluorescence examination on frozen sections and ultrastructural examination. At direct immunofluorescence, fixation of anti-IgM serum on myelinated fibers was present in 7 cases. At ultrastructural examination, a widening of some myelin lamellae at the periphery of a few fibers was visible in 8 cases. A few fibers with hypermyelination were present in 5 cases. In 2 of these 5 cases widening of some myelin lamellae was present in numerous fibers, 88% in one of them. Frequently, there was a major widening of some myelin lamellae with dilated lamellae present in the inner part of the myelin sheath. Certain lamellae were more dilated, up to 50 nm. Occasionally, enlarged lamellae were not compacted with each other. The authors also examined nerve biopsies from 36 patients with IgM monoclonal gammopathy of undetermined significance and anti-MAG activity, but found only one case with major widening of some myelin lamellae. Five other cases with major widening of some myelin lamellae, 4 Waldenström's macroglobulinemia and 1 IgM monoclonal gammopathy of undetermined significance, have been reported. Given that demyelinating neuropathies are far more numerous in cases with IgM monoclonal gammopathy of undetermined significance, it is likely that cases of indolent Waldenström's macroglobulinemia are prone to develop major myelin modifications, possibly due to another mechanism, added to the classic anti-MAG activity.

High-frequency stimulation of the globus pallidus internalis in Parkinson's disease: a study of seven cases

The effectiveness of ventroposterolateral pallidotomy in the treatment of akinesia and rigidity is not a new discovery and agrees with recent investigations into the pathogenesis of Parkinson's disease, which highlight the role played by the unbridled activity of the subthalamic nucleus (STN) and the consequent overactivity of the globus pallidus internalis (GPi). Because high-frequency stimulation can reversibly incapacitate a nerve structure, we applied stimulation to the same target. Seven patients suffering from severe Parkinson's disease (Stages III-V on the Hoehn and Yahr scale) and, particularly, bradykinesia, rigidity, and levodopa-induced dyskinesias underwent unilateral electrode implantation in the posteroventral GPi. Follow-up evaluation using the regular Unified Parkinson's Disease Rating Scale has been conducted for 1 year in all seven patients, 2 years in five of them, and 3 years in one. In all cases high-frequency stimulation has alleviated akinesia and rigidity and has generally improved gait and speech disturbances. In some cases tremor was attenuated. In a similar manner, the authors observed a marked diminution in levodopa-induced dyskinesias. This could be an excellent primary therapy for younger patients exhibiting severe bradykinesia, rigidity, and levodopa-induced dyskinesias, which would allow therapists to keep ventroposterolateral pallidotomy in reserve as a second weapon.

Allelic origin of the abnormal prion protein isoform in familial prion diseases

The hallmark of prion diseases is the presence of an aberrant isoform of the prion protein (PrP(res)) that is insoluble in nondenaturing detergents and resistant to proteases. We investigated the allelic origin of PrP(res) in brains of subjects heterozygous for the D178N mutation linked to fatal familial insomnia (FFI) and a subtype of Creutzfeldt-Jakob disease (CJD178), as well as for insertional mutations associated with another CJD subtype. We found that in FFI and CJD178 subjects, only mutant PrP was detergent-insoluble and protease-resistant. Therefore, PrP(res) derives exclusively from the mutant allele carrying the D178N mutation. In contrast, in the CJD subtype harboring insertional mutations, wild-type PrP was also detergent-insoluble and likely to be protease-resistant. Our findings indicate that the participation of the wild-type PrP in the formation of PrP(res) depends on the type of mutations, providing an insight into the molecular mechanisms underlying the phenotypic heterogeneity in familial prion diseases.

Familial prion disease with a novel 144-bp insertion in the prion protein gene in a Basque family

Three members of a Basque family carrying a novel six R2 octapeptide repeat 144-bp insertion in the prion protein gene (PRNP) showed a slowly progressive dementia associated with cerebellar signs, myoclonic jerks, and seizures. Although postmortem examination revealed only focal and minimal spongiform degeneration in one subject with a 4-year course, significant astrogliosis and neuronal loss were associated with pronounced spongiform degeneration in the patient with a duration of symptoms of 10 years. Prion protein (PrP)-immunoreactive patches with a unique morphology were present in the molecular layer of the cerebellum in both subjects. Western blot analysis demonstrated the presence of protease-resistant prion protein (PrPres) with the same characteristics (size and ratio of the three differently glycosylated isoforms) of that found in typical sporadic Creutzfeldt-Jakob disease (CJD129M/M, PrPres type 1). The amount of PrPres correlated with presence and severity of spongiform degeneration in the cerebral cortex. The findings suggest that a relatively low rate of PrPres deposition is the cause of the lack of spongiform degeneration in subjects carrying a 144-bp insertion in PRNP. The presence of PrP-immunoreactive patches with unique morphology in the molecular layer of the cerebellum is a hallmark of certain prion encephalopathies with insertional mutations and is useful in the diagnosis of this subtype of human prion disease.

Widespread dilatation of perivascular spaces: a leukoencephalopathy causing dementia

A 68-year-old demented woman had widespread dilatation of perivascular spaces in the cerebral white matter for at least 12 years. There were no micro-infarcts, but some vessel walls in the white matter were thickened by a loose fibrosis. Our case does not correspond to Binswanger's disease or any other known vascular leukoencephalopathy. The longstanding evolution points to a nonfamilial leukoencephalopathy of probable vascular origin.

Enzyme immunoassay for myelin basic protein in cerebrospinal fluid

Myelin basic proteins (MBPs) are a set of proteins making up about 30% of the protein content of the central nervous system myelin. Four human isoforms have been identified. The most abundant is a highly conserved 18.5 kDa polypeptide. For this species, the amino acid sequence homologies between human and monkey or human and chick are 98.2% and 71.1%, respectively. As a consequence, there is a very good immunological cross-reactivity between the mammalian MBP. This protein has been extensively used to induce experimental allergic encephalomyelits (EAE) in numerous animals. The evolution of chronic EAE in animal is similar to that of multiple sclerosis (MS), a demyelinating human pathology, and chronic EAE is considered to be an animal model of MS. In demyelinating pathologies, MBP concentration in the cerebrospinal fluid (CSF) is considered to be a good marker of demyelination. MBP concentration, in biological fluids, is generally determined by radioimmunoassay (RIA). The RIA technique currently used is highly sensitive (0.1-2.5 ng/ml) but has the drawback of requiring the handling of radioactivity and frequent labelling of MBP. So we developed a new enzyme immunoassay (EIA) technique. Our technique has the same sensitivity as RIA, needs only small volumes of CSF (50 microliters) and the enzyme-labelled MBP tracer is stable for at least 12 months.

Cardiac complications in non-insulin-dependent diabetes mellitus

There is clear evidence of the negative influence of type I or II diabetes non-insulin-dependent diabetes mellitus (NIDDM) on the prevalence, severity, and prognosis of cardiovascular disease. Epidemiologic studies have confirmed the relationship between NIDDM and the occurrence of coronary artery disease (CAD) and cardiac heart failure (CHF). The clinical aspects of NIDDM cardiac complications include a high rate of silent events, which merit an improvement in their diagnosis and treatment. Besides pharmacological therapy, aggressive approaches including percutaneous transluminal coronary angioplasty (PTCA), and coronary surgery should be considered for the treatment of stable angina. IN some subgroups, the benefit of surgery has been proven. Available data indicate that diabetes (both type I and II) is a risk factor for an increase in morbidity and mortality following coronary bypass surgery. These data do not differentiate results between type I and type II diabetes. The indications for surgical revascularization are: three-vessel disease, left main artery stenosis, two-vessel disease including proximal left anterior descending artery stenosis, and two-vessel disease with left ventricular dysfunction. For PTCA, diabetes (type I more than type II) renders the technique more difficult and restenosis more frequent. From the results obtained in the general population and from a few specific studies, it is suspected that, in type II diabetes, PTCA and CABG are superior to conventional medical treatment. However, further specific studies on the beneficial effects of PTCA/CABG over optimal medical therapy are needed, at least in some angiographic conditions. Management of the diabetic patient with acute myocardial infarction is for the most part similar to the nondiabetic patient, with certain special considerations. Treatment includes thrombolytic therapy, invasive management, surgery, PTCA, beta blocker use, and aspirin use. Finally, diabetes mellitus is a cause of systolic and diastolic function, leading to clinical signs of CHF. Conventional medical therapy also applies to cardiac failure complicating diabetes. Medical therapy includes as the first line diuretics and angiotensin-converting enzyme inhibitors. We conclude that cardiac care can be improved in diabetic patients. For the time being, the first step is to improve the detection of coronary artery disease. As serious events are more likely to occur in the diabetic population, it would be easier (shorter studies and less patients) to demonstrate the benefit of a selected therapy. Further studies are therefore required. In the meantime, special efforts can be made: (1) prevent the development of coronary artery disease. Preventive measures aimed at the control of risk factors at the individual level must be optimal. What should be promoted is a more global approach to the patient, taking into account all parts of the risk factor profile, in order to amplify the reduction in risk and in cardiovascular morbidity and mortality. (2) When CAD is confirmed: the goal is to prevent all major cardiac events: unstable angina, myocardial infarction, sudden death, and CHF secondary to silent ischemic events. This can be achieved through the improvement of the accuracy of noninvasive diagnostic procedures, taking into account the cost of these procedures and the absence of pain perception in diabetic patients.

Evidence of presence of poliovirus genomic sequences in cerebrospinal fluid from patients with postpolio syndrome

The postpolio syndrome (PPS) is characterized by new neuromuscular symptoms occurring 30 to 40 years after the acute episode of poliomyelitis paralysis. The presence of the poliovirus RNA genome in the cerebrospinal fluid from 10 patients with PPS and from 23 control patients was sought by using reverse transcription and a PCR specific for polioviruses and/or other enteroviruses. Poliovirus-specific genomic sequences in the 5' untranslated region and in the capsid region (VP1) were detected by reverse transcription PCR in 5 of 10 patients with PPS but in none of the control patients. Sequencing confirmed the presence of mutated poliovirus sequences. This finding suggests persistent viral infection in the central nervous system related to the presence of poliovirus genomes.

Intergenerational instability of the CAG repeat of the gene for Machado-Joseph disease (MJD1) is affected by the genotype of the normal chromosome: implications for the molecular mechanisms of the instability of the CAG repeat

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder caused by unstable expansion of a CAG repeat in the MJD1 gene at 14q32.1. To identify elements affecting the intergenerational instability of the CAG repeat, we investigated whether the CGG/GGG polymorphism at the 3' end of the CAG repeat affects intergenerational instability of the CAG repeat. The [expanded (CAG)n-CGG]/[normal (CAG)n-GGG] haplotypes were found to result in significantly greater instability of the CAG repeat compared to the [expanded (CAG)n-CGG]/[normal (CAG)n-CGG] or [expanded (CAG)nGGG]/[normal (CAG)n-GGG] haplotypes. Multiple stepwise logistic regression analysis revealed that the relative risk for a large intergenerational change in the number of CAG repeat units (< -2 or > 2) is 7.7-fold (95% CI: 2.5-23.9) higher in the case of paternal transmission than in that of maternal transmission and 7.4-fold (95% CI: 2.4-23.3) higher in the case of transmission from a parent with the [expanded (CAG)n-CGG]/[normal (CAG)n-GGG] haplotypes than in that of transmission from a parent with the [expanded (CAG)n-CGG]/[normal (CAG)n-CGG] or [expanded (CAG)n-GGG]/[normal (CAG)n-GGG] haplotypes. The combination of paternal transmission and the [expanded (CAG)n-CGG]/[normal (CAG)n-GGG] haplotypes resulted in a 75.2-fold (95% CI: 9.0-625.0) increase in the relative risk compared with that of maternal transmission and the [expanded (CAG)n-CGG]/[normal (CAG)n-CGG] or [expanded (CAG)n-GGG]/[normal (CAG)n-GGG] haplotypes. The results suggest that an inter-allelic interaction is involved in the intergenerational instability of the expanded CAG repeat.