CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2006
Massimo Siciliano
SUMMARY 1In animals and in cultured neurons, l -carnitine and acetyl- l -carnitine (ALCAR) have been shown to counteract some of the toxic effects of ammonia. In order to detect similar properties in humans, we studied neuronal function after ALCAR administration in cirrhotics with hepatic encephalopathy (HE). 2Eighteen cirrhotic patients with persistent HE and hyperammonaemia were investigated in the present study and six subjects with a prior transient ischaemic attack were used as controls. 3The prominent positive component that occurs approximately 100 msec after the pattern reversal (P100) latencies of visual-evoked potentials were used to evaluate neuronal function. At first, the P100 latency was measured in six cirrhotic patients with HE and in the six controls before the administration of 0.5 g ALCAR in 50 mL isotonic saline (infusion rate 10 mL/min) and 15, 30, 60 and 90 min later. 4A significant reduction in P100 latencies was identified 30 min after ALCAR infusion in HE patients, whereas no differences were observed in controls. 5Thereafter, the P100 latency was evaluated in the 12 other cirrhotic patients with HE only before and 30 min after ALCAR infusion. The mean of the P100 latencies measured in these subjects was significantly shorter after ALCAR infusion compared with values obtained before ALCAR administration (mean (SD) 130.78 5.50 vs 136.08 6.45 msec, respectively; P = 0.0013). 6The present study suggests that a single intravenous dose of ALCAR may transiently improve neuronal function in cirrhotic patients with persistent HE and hyperammonaemia. [source]

Encephalopathy with combined lithium-risperidone administration

ACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2008
K. Boora
Objective:, Lithium-neuroleptics induced encephalopathy is a rare drug interaction. Here I am reporting a patient who developed reversible encepatholopathy with lithium-risperidone combination. Method:, A single case report. Result:, A patient of bipolar disorder, who presented with manic symptoms with psychotic feature, started with a combination of lithium and risperidone. Within few days, the patient developed encepatholopathy, which reversed upon discontinuation of lithium and risperidone. Conclusion:, Combining lithium and neuroleptic is useful in treatment of bipolar disorder. However, encepatholapthy can be anticipated to result when lithium is used with high potency anti-psychotic such as haloperidol and risperidone and there are baseline EEG abnormalities. [source]

Valproic Acid-Induced Hyperammonemic Encephalopathy with Triphasic Waves

EPILEPSIA, Issue 7 2000
Akira Kifune
Summary: Purpose: To examine a patient with valproic acid (VPA)-induced hyperammonemic encephalopathy accompanied by triphasic waves. Methods: A 61-year-old male patient with epilepsy experienced disturbance of consciousness after VPA dose was increased because of poor seizure control. The electroencephalogram (EEG) taken on admission revealed triphasic waves and high-amplitude ,-activity with frontal predominance. Although serum hepatic enzymes, such as AST and ALT, were normal, serum ammonium level was high at 96 ,g/dl (normal range, 3,47 ,g/dl). Serum amino acid analysis showed multiple minor abnormalities. Administration of VPA was discontinued immediately after admission, while other anticonvulsants were continued. Results: The patient's condition was improved on the fourth day of admission. An EEG, serum ammonium level, and amino acid profile were normal on the eighth day. Based on VPA administration, serum ammonium levels, and results of amino acid analysis, this patient had VPA-induced hyperammonemic encephalopathy. Conclusions: Our case indicates that caution is required if triphasic waves appear in VPA-induced hyperammonemic encephalopathy. [source]

TIPS versus drug therapy in preventing variceal rebleeding in advanced cirrhosis: A randomized controlled trial

HEPATOLOGY, Issue 2 2002
Àngels Escorsell
Prevention of variceal rebleeding is mandatory in cirrhotic patients. We compared the efficacy, safety, and cost of transjugular intrahepatic portosystemic shunt (TIPS) versus pharmacologic therapy in preventing variceal rebleeding in patients with advanced cirrhosis. A total of 91 Child-Pugh class B/C cirrhotic patients surviving their first episode of variceal bleeding were randomized to receive TIPS (n = 47) or drug therapy (propranolol + isosorbide-5-mononitrate) (n = 44) to prevent variceal rebleeding. Mean follow-up was 15 months. Rebleeding occurred in 6 (13%) TIPS-treated patients versus 17 (39%) drug-treated patients (P = .007). The 2-year rebleeding probability was 13% versus 49% (P = .01). A similar number of reinterventions were required in the 2 groups; these were mainly angioplasty ± restenting in the TIPS group (90 of 98) and endoscopic therapy for rebleeding in the medical group (45 of 62) (not significant). Encephalopathy was more frequent in TIPS than in drug-treated patients (38% vs. 14%, P = .007). Child-Pugh class improved more frequently in drug-treated than in TIPS-treated patients (72% vs. 45%; P = .04). The 2-year survival probability was identical (72%). The identified cost of therapy was double for TIPS-treated patients. In summary, medical therapy was less effective than TIPS in preventing rebleeding. However, it caused less encephalopathy, identical survival, and more frequent improvement in Child-Pugh class with lower costs than TIPS in high-risk cirrhotic patients. This suggests that TIPS should not be used as a first-line treatment, but as a rescue for failures of medical/endoscopic treatments (first-option therapies). [source]

Information, labelling, and vertical coordination: an analysis of the Italian meat supply networks

AGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 3 2008
Alessandro Banterle
After the Bovine Spongiform Encephalopathy (BSE) crisis, the European Union (EU) introduced mandatory and voluntary labelling for meat products to reduce the food safety concerns of consumers and to ensure a better distribution of liability among agents of the meat supply chain. The purpose of this article is to evaluate whether voluntary traceability labelling, introduced by Regulation 1760/2000, can be considered a useful instrument for both the producers and consumers of meat products. Attention is focused on the vertical coordination effects of introducing voluntary labelling along the beef chain and on the interest the Italian consumer shows in labelled information on meat products. Two surveys were conducted: one addressing Italian meat organizations that signed voluntary labelling agreements and the other a sample of 1,025 Italian consumers. With regard to supply, the survey revealed that improved traceability led to a better redistribution of liability among the agents of the meat supply chain and to a strengthening of vertical agreements. Regarding the consumers, the results showed a notable consumer interest in the labelled information such as the meat origin and the information related to the system of cattle breeding, cattle feeding, and the date of slaughtering. © 2008 Wiley Periodicals, Inc., [source]

Price transmission in the Spanish bovine sector: the BSE effect

AGRICULTURAL ECONOMICS, Issue 1 2010
Islam Hassouneh
Food scare; BSE crisis; Price transmission; Regime-switching Abstract A regime-switching vector error correction model is applied to monthly price data to assess the impact of Bovine Spongiform Encephalopathy (BSE) outbreaks on price relationships and patterns of transmission among farm and retail markets for bovines in Spain. To evaluate the degree to which price transmission is affected by BSE food scares, a BSE food scare index is developed and used to determine regime switching. Results suggest that BSE scares affect beef producers and retailers differently. Consumer prices are found to be weakly exogenous and not found to react to BSE scares, while producer prices are conversely adjusted. The magnitude of the adjustment is found to depend on the magnitude of the BSE scare. [source]

Lactate Detection by MRS in Mitochondrial Encephalopathy: Optimization of Technical Parameters

JOURNAL OF NEUROIMAGING, Issue 1 2008
Antônio José da Rocha MD
ABSTRACT Mitochondriopathies are a heterogeneous group of diseases with variable phenotypic presentation, which can range from subclinical to lethal forms. They are related either to DNA mutations or nuclear-encoded mitochondrial genes that affect the integrity and function of these organelles, compromising adenosine triphosphate (ATP) synthesis. Magnetic resonance (MR) is the most important imaging technique to detect structural and metabolic brain abnormalities in mitochondriopathies, although in some cases these studies may present normal results, or the identified brain abnormalities may be nonspecific. Magnetic resonance spectroscopy (MRS) enables the detection of high cerebral lactate levels, even when the brain has normal appearance by conventional MR scans. MRS is a useful tool for the diagnosis of mitochondriopathies, but must be correlated with clinical, neurophysiological, biochemical, histological, and molecular data to corroborate the diagnosis. Our aim is to clarify the most relevant issues related to the use of MRS in order to optimize its technical parameters, improving its use in the diagnosis of mitochondriopathies, which is often a challenge. [source]

Encephalopathy after furosemide use in nephrotic syndrome

JOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 3 2007
Ajay P Sharma
Abstract: An 18-year-old girl with nephrotic syndrome presented with a life-threatening respiratory failure and a severe encephalopathy, shortly after being started on furosemide. The evaluation confirmed furosemide as the sole culprit for the clinical manifestations. This case highlights an unpredictable dose,response relationship of furosemide. The pathophysiological basis, differential diagnosis and clinical implications of the observed findings are discussed. [source]

Elevated Cerebrospinal Fluid Tau Protein Levels in Wernicke's Encephalopathy

ALCOHOLISM, Issue 6 2008
Sachio Matsushita
Objective:, Limited neuronal cell loss is seen in the neuropathology of Wernicke's encephalopathy (WE), but the extent of neuronal damage has not been well studied. Moreover, there is still a debate as to whether alcohol itself causes brain damage in humans. Although, it is difficult to examine the extent of neuronal damage in living patients, recent studies have revealed that total tau protein levels in the cerebrospinal fluid (CSF) reflect the rate of neuronal degeneration. Therefore, we hypothesized that the elevated CSF total tau in patients with WE was due to neuronal damage and thus we examined CSF total tau protein in patients with WE, as well as in those with alcohol withdrawal delirium (WD) and Korsakoff syndrome (KS). We also examined CSF total tau in nonalcohol dependent patients with Alzheimer's disease (AD) as a disease control. Methods:, CSF samples were obtained from 13 acute WE patients with alcohol dependence, 9 WD patients with alcohol dependence and 16 KS patients with alcohol dependence, and from 20 nonalcohol dependent AD patients. CSF was also obtained from 10 of the WE patients after their disease had progressed to the chronic stage. CSF tau protein levels in all samples were determined by sandwich enzyme-linked immunosorbent assay. Tau phosphorylated at threonine 181 (p-tau181) and amyloid ,-protein ending at amino acid 42 (A,42) in CSF were also determined for comparison between acute WE with AD. Results:, Total tau was significantly elevated in acute WE and decreased on long-term follow-up, but was not elevated in WD or KS. The patterns of p-tau181 and A,42 differed between acute WE and AD. Conclusions:, Intense neuronal cell death occurs transiently in WE, and the mechanism differs from that in AD. Neuronal damage is generally unaccompanied in WD. These results suggest that CSF total tau is a useful biological marker for WE. [source]

The peri-microvascular edema in hippocampal CA1 area in a rat model of sepsis

NEUROPATHOLOGY, Issue 3 2007
Ilker Mustafa Kafa
Encephalopathy is a common complication of sepsis. However, little is known about the morphological changes that occur in the brain during sepsis. In this study, fecal peritonitis was induced in Wistar rats, which had been monitored for 4 h before their brains were removed and samples from the CA1 area taken. In addition to higher blood pressure with a decreasing pattern and a significant drop in rectal temperature, an increased heart rate and marked respiratory failure were observed. The tissue was investigated and compared with corresponding hippocampal samples taken from sham-operated and not operated control groups. Significantly more peri-microvascular edema was found in the hippocampal CA1 area in the septic group. The percentages of the peri-microvascular edema were 158.57 ± 3.6%, 122.84 ± 1.5% and 120.24 ± 1.9% in the fecal peritonitis group, sham-operated and not operated control groups, respectively. The results may suggest that the edema observed around the microvessels may participate in the pathogenesis of the septic encephalopathy probably by causing in the microvascular permeability characteristics. [source]

Molecular neuropathology of MELAS: level of heteroplasmy in individual neurones and evidence of extensive vascular involvement

NEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 4 2006
J. Betts
Mitochondrial DNA (mtDNA) disease is an important genetic cause of neurological disability. A variety of different clinical features are observed and one of the most common phenotypes is MELAS (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis and Stroke-like episodes). The majority of patients with MELAS have the 3243A>G mtDNA mutation. The neuropathology is dominated by multifocal infarct-like lesions in the posterior cortex, thought to underlie the stroke-like episodes seen in patients. To investigate the relationship between mtDNA mutation load, mitochondrial dysfunction and neuropathological features in MELAS, we studied individual neurones from several brain regions of two individuals with the 3243A>G mutation using dual cytochrome c oxidase (COX) and succinate dehydrogenase (SDH) histochemistry, and Polymerase Chain Reaction Restriction Fragment Lenght Polymorphism (PCR-RFLP) analysis. We found a low number of COX-deficient neurones in all brain regions. There appeared to be no correlation between the threshold level for the 3243A>G mutation to cause COX deficiency within single neurones and the degree of pathology in affected brain regions. The most severe COX deficiency associated with the highest proportion of mutated mtDNA was present in the walls of the leptomeningeal and cortical blood vessels in all brain regions. We conclude that vascular mitochondrial dysfunction is important in the pathogenesis of the stroke-like episodes in MELAS patients. As migraine is a commonly encountered feature in MELAS, we propose that coupling of the vascular mitochondrial dysfunction with cortical spreading depression (CSD) might underlie the selective distribution of ischaemic lesions in the posterior cortex in these patients. [source]

Measles-Associated Encephalopathy in Children with Renal Transplants

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 6 2006
A. Turner
Two children, boys of 8 and 13 years, presented with measles-associated encephalopathy several years after kidney transplantation for congenital nephrotic syndrome. In the absence of prior clinical measles, the neurological symptoms initially eluded diagnosis, but retrospective analysis of stored samples facilitated the diagnosis of measles-associated encephalopathy without recourse to biopsy of deep cerebral lesions. Each had received a single dose of measles mumps and rubella vaccine before 12 months of age. Prior vaccination, reduction of immunosuppression and treatment with intravenous immunoglobulin and ribavirin may have contributed to their survival. Persistent measles virus RNA shedding, present in one child, was not controlled by treatment with i.v. ribavirin. Two years later, both patients continue to have functioning allografts with only minimal immunosuppression. These cases illustrate the difficulty in diagnosing measles-associated encephalopathy in the immunocompromised host, even in the era of molecular diagnostics, and highlight the renewed threat of neurological disease in communities with incomplete herd immunity. [source]

Lithium-induced Hashimoto's encephalopathy: a case report

BIPOLAR DISORDERS, Issue 7 2008
Masanori Nagamine
Objective:, To report on a patient with Hashimoto's encephalopathy induced by lithium. Patient and interventions:, A 61-year-old woman with a type II bipolar disorder and a history of lithium-induced thyrotoxicosis associated with silent thyroiditis was hospitalized to treat a severe major depressive episode. Given long-term treatment with levothyroxine for hypothyroidism that had resulted from silent thyroiditis, endogenous hormone in thyroid follicles was assumed to be minimized by the negative feedback, decreasing risk of recurrent thyrotoxicosis if lithium were restarted. Results:, Lithium clearly relieved the patient's depressive symptoms, but after 40 days encephalopathy developed. Thyrotoxicosis was ruled out, and serum antithyroid antibody titers were elevated. In the cerebrospinal fluid, protein content was substantially elevated and antithyroid antibodies were detected. Encephalopathy resolved dramatically after course of intravenous pulse therapy with methylprednisolone. Conclusions:, We believe that autoantibodies against antigens shared by the thyroid gland and the brain were induced by exposure to lithium, causing the patient to develop Hashimoto's encephalopathy. [source]

Failure of immunocompetitive capillary electrophoresis assay to detect disease-specific prion protein in buffy coat from humans and chimpanzees with Creutzfeldt-Jakob disease

ELECTROPHORESIS, Issue 5 2003
Larisa Cervenakova
Abstract The emergence of a new environmentally caused variant of Creutzfeldt-Jakob disease (vCJD), the result of food-born infection by the causative agent of bovine spongiform encephalopathy (BSE), has stimulated research on a practical diagnostic screening test. The immunocompetitive capillary electrophoresis (ICCE) assay has been reported to detect disease-specific, proteinase-resistant prion protein (PrPres) in the blood of scrapie-infected sheep. We have applied this method to blood from CJD-infected chimpanzees and humans. The threshold of detection achieved with our ICCE was 0.6 nM of synthetic peptide corresponding to the prion protein (PrP) C -terminus, and 2 nM of recombinant human PrP at the optimized conditions. However, the test was unable to distinguish between extracts of leucocytes from healthy and CJD-infected chimpanzees, and from healthy human donors and patients affected with various forms of CJD. Thus, the ICCE assay as presently performed is not suitable for use as a screening test in human transmissible spongiform encephalopathies (TSEs). [source]

Revised terminology and concepts for organization of seizures and epilepsies: Report of the ILAE Commission on Classification and Terminology, 2005,2009

EPILEPSIA, Issue 4 2010
Anne T. Berg
Summary The International League Against Epilepsy (ILAE) Commission on Classification and Terminology has revised concepts, terminology, and approaches for classifying seizures and forms of epilepsy. Generalized and focal are redefined for seizures as occurring in and rapidly engaging bilaterally distributed networks (generalized) and within networks limited to one hemisphere and either discretely localized or more widely distributed (focal). Classification of generalized seizures is simplified. No natural classification for focal seizures exists; focal seizures should be described according to their manifestations (e.g., dyscognitive, focal motor). The concepts of generalized and focal do not apply to electroclinical syndromes. Genetic, structural,metabolic, and unknown represent modified concepts to replace idiopathic, symptomatic, and cryptogenic. Not all epilepsies are recognized as electroclinical syndromes. Organization of forms of epilepsy is first by specificity: electroclinical syndromes, nonsyndromic epilepsies with structural,metabolic causes, and epilepsies of unknown cause. Further organization within these divisions can be accomplished in a flexible manner depending on purpose. Natural classes (e.g., specific underlying cause, age at onset, associated seizure type), or pragmatic groupings (e.g., epileptic encephalopathies, self-limited electroclinical syndromes) may serve as the basis for organizing knowledge about recognized forms of epilepsy and facilitate identification of new forms. [source]

Epilepsy and respiratory chain defects in children with mitochondrial encephalopathies

EPILEPSIA, Issue 11 2008
Divya Khurana
First page of article [source]

Neurologic manifestations of ulcerative colitis

EUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2007
R. Scheid
Ulcerative colitis (UC) has traditionally been considered to be an inflammatory disease limited to the colonic mucosa. However, since it has been shown that UC is frequently accompanied by various extraintestinal disorders, there is increasing evidence that UC may also manifest in the nervous system. The following review focuses particularly on these possible manifestations of UC, both in the peripheral (PNS), and in the central nervous system (CNS). A systematic literature search according to the MEDLINE database was performed for this purpose. Although a reliable differentiation may clinically not always be possible, three major pathogenic entities can be differentiated: (i) cerebrovascular disease as a consequence of thrombosis and thromboembolism; (ii) systemic and cerebral vasculitis; (iii) probably immune mediated neuropathy and cerebral demyelination. With the exception of thromboembolism and sensorineural hearing loss, evidence for a causal relationship relies merely on single case reports or retrospective case series. Considering the CNS-manifestations, similarities between UC-associated disorders of the white matter and acute disseminated encephalomyelitis (ADEM) are obvious. Epileptic seizures, unspecified encephalopathies and confusional states are most likely epiphenomena that have to be regarded symptomatic rather than as own entities. A prospective study on the neurologic aspects of UC would be very welcome. [source]

CSF analysis in patients with sporadic CJD and other transmissible spongiform encephalopathies

EUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2007
A. Green
Patients with suspected Creutzfeldt,Jakob disease (CJD) often have routine cerebrospinal fluid (CSF) analysis performed to exclude treatable inflammatory conditions; however, little information is available about the range of results obtained for CSF tests in patients with sporadic CJD and other transmissible spongiform encephalopathies (TSE). Data from 450 patients with sporadic CJD and 47 patients with other TSEs were collected as part of an EC-supported multinational study. Raised white cell counts of >5 cells/,l were found in three of 298 patients with sporadic CJD, with two cell counts of 7 cells/,l and one of 20 cells/,l. Total protein concentrations of >0.9 g/l were found in five of 438 patients with sporadic CJD, although none had a concentration of >1 g/l. CSF oligoclonal IgG was detected in eight of 182 sporadic CJD patients. Of the patients with other TSEs, six had elevated cell counts ranging from 6 to 14 cells/,l but none had total protein concentrations of >0.9 g/l and one patient had detectable oligoclonal IgG. None of the patients with sporadic CJD or other TSEs had abnormalities in all three tests. [source]

Codon 129 polymorphism and the E200K mutation do not affect the cellular prion protein isoform composition in the cerebrospinal fluid from patients with Creutzfeldt,Jakob disease

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2010
Matthias Schmitz
Abstract The cellular prion protein (PrPc) is a multifunctional, highly conserved and ubiquitously expressed protein. It undergoes a number of modifications during its post-translational processing, resulting in different PrPc glycoforms and truncated PrPc fragments. Limited data are available in humans on the expression and cleavage of PrPc. In this study we investigated the PrPc isoform composition in the cerebrospinal fluid from patients with different human prion diseases. The first group of patients was affected by sporadic Creutzfeldt,Jakob disease exhibiting different PrP codon 129 genotypes. The second group contained patients with a genetic form of Creutzfeldt,Jakob disease (E200K). The third group consisted of patients with fatal familial insomnia and the last group comprised cases with the Gerstmann,Sträussler,Scheinker syndrome. We examined whether the PrP codon 129 polymorphism in sporadic Creutzfeldt,Jakob disease as well as the type of prion disease in human patients has an impact on the glycosylation and processing of PrPc. Immunoblotting analyses using different monoclonal PrPc antibodies directed against various epitopes of PrPc revealed, for all examined groups of patients, a consistent predominance of the glycosylated PrPc isoforms as compared with the unglycosylated form. In addition, the antibody SAF70 recognized a variety of PrPc fragments with sizes of 21, 18, 13 and 12 kDa. Our findings indicate that the polymorphisms at PrP codon 129, the E200K mutation at codon 200 or the examined types of human transmissible spongiform encephalopathies do not exert a measurable effect on the glycosylation and processing of PrPc in human prion diseases. [source]

Connecting the dots: trafficking of neurotrophins, lectins and diverse pathogens by binding to the neurotrophin receptor p75NTR

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2003
Rafal Butowt
Abstract The common receptor for neurotrophins, p75, has important roles in internalization and trafficking of neurotrophins along axons. Recent studies show that an astonishing array of proteins, including lectins, pathogens and neurotoxins, bind the p75 receptor, suggesting that they can hijack and utilize this receptor for trafficking between neuronal populations within the nervous system. Such pathogens include the neurologically important rabies viruses, prion proteins, ,-amyloid and possibly tetanus toxin. These proteins may hijack existing transport machineries designed to traffick neurotrophins, thus allowing the infiltration and distribution of pathogens and toxins among vulnerable neuronal populations with devastating effects, as seen in rabies, prion encephalopathies, Alzheimer's disease and tetanic muscle spasm. The discovery of an entry and transport machinery that is potentially shared between pathogens and neurotrophins sheds light ono trafficking systems in the nervous system and may assist the design of novel therapeutic avenues that prevent or slow the progression of diverse chronic and acute neurological disorders. [source]

Hyperefficient PrPSc amplification of mouse-adapted BSE and scrapie strain by protein misfolding cyclic amplification technique

FEBS JOURNAL, Issue 10 2009
Aiko Fujihara
Abnormal forms of prion protein (PrPSc) accumulate via structural conversion of normal PrP (PrPC) in the progression of transmissible spongiform encephalopathy. Under cell-free conditions, the process can be efficiently replicated using in vitro PrPSc amplification methods, including protein misfolding cyclic amplification. These methods enable ultrasensitive detection of PrPSc; however, there remain difficulties in utilizing them in practice. For example, to date, several rounds of protein misfolding cyclic amplification have been necessary to reach maximal sensitivity, which not only take several weeks, but also result in an increased risk of contamination. In this study, we sought to further promote the rate of PrPSc amplification in the protein misfolding cyclic amplification technique using mouse transmissible spongiform encephalopathy models infected with either mouse-adapted bovine spongiform encephalopathy or mouse-adapted scrapie, Chandler strain. Here, we demonstrate that appropriate regulation of sonication dramatically accelerates PrPSc amplification in both strains. In fact, we reached maximum sensitivity, allowing the ultrasensitive detection of < 1 LD50 of PrPSc in the diluted brain homogenates, after only one or two reaction rounds, and in addition, we detected PrPSc in the plasma of mouse-adapted bovine spongiform encephalopathy-infected mice. We believe that these results will advance the establishment of a fast, ultrasensitive diagnostic test for transmissible spongiform encephalopathies. [source]

Full-length prion protein aggregates to amyloid fibrils and spherical particles by distinct pathways

FEBS JOURNAL, Issue 9 2008
Driss El Moustaine
As limited structural information is available on prion protein (PrP) misfolding and aggregation, a causative link between the specific (supra)molecular structure of PrP and transmissible spongiform encephalopathies remains to be elucidated. In this study, high pressure was utilized, as an approach to perturb protein structure, to characterize different morphological and structural PrP aggregates. It was shown that full-length recombinant PrP undergoes ,-sheet aggregation on high-pressure-induced destabilization. By tuning the physicochemical conditions, the assembly process evolves through two distinct pathways leading to the irreversible formation of spherical particles or amyloid fibrils, respectively. When the PrP aggregation propensity is enhanced, high pressure induces the formation of a partially unfolded aggregated protein, AggHP, which relaxes at ambient pressure to form amorphous aggregates. The latter largely retain the native secondary structure. On prolonged incubation at high pressure, followed by depressurization, AggHP transforms to a monodisperse population of spherical particles of about 20 nm in diameter, characterized by an essentially ,-sheet secondary structure. When the PrP aggregation propensity is decreased, an oligomeric reaction intermediate, IHP, is formed under high pressure. After pressure release, IHP relaxes to the original native structure. However, on prolonged incubation at high pressure and subsequent depressurization, it transforms to amyloid fibrils. Structural evaluation, using optical spectroscopic methods, demonstrates that the conformation adopted by the subfibrillar oligomeric intermediate, IHP, constitutes a necessary prerequisite for the formation of amyloids. The use of high-pressure perturbation thus provides an insight into the molecular mechanism of the first stages of PrP misfolding into amyloids. [source]

Copper is required for prion protein-associated superoxide dismutase-l activity in Pichia pastoris

FEBS JOURNAL, Issue 5 2007
Carina Treiber
The prion protein (PrP) is the key protein implicated in transmissible spongiform encephalopathies. It is a metalloprotein that binds manganese and copper. The latter is involved in the physiological function of the protein. We have previously found that PrP expression in Pichia pastoris affects intracellular metal ion concentrations and that formation of protease-resistant PrP is induced by additional copper and/or manganese. In this study, we show that heterologously expressed PrP is post-translationally modified and transported to the cell wall. We found by combining three different test systems that PrP itself had gained superoxide dismutase-like activity in P. pastoris. However, this activity could not be inhibited by KCN and depended on additional copper in the medium. Thus, this study defines the conditions under which PrP exhibits superoxide dismutase-like activity by showing that copper must be present for the protein to participate in scavenging and detoxification of reactive oxygen species. [source]

Synthesis and structural characterization of a mimetic membrane-anchored prion protein

FEBS JOURNAL, Issue 6 2006
Matthew R. Hicks
During pathogenesis of transmissible spongiform encephalopathies (TSEs) an abnormal form (PrPSc) of the host encoded prion protein (PrPC) accumulates in insoluble fibrils and plaques. The two forms of PrP appear to have identical covalent structures, but differ in secondary and tertiary structure. Both PrPC and PrPSc have glycosylphospatidylinositol (GPI) anchors through which the protein is tethered to cell membranes. Membrane attachment has been suggested to play a role in the conversion of PrPC to PrPSc, but the majority of in vitro studies of the function, structure, folding and stability of PrP use recombinant protein lacking the GPI anchor. In order to study the effects of membranes on the structure of PrP, we synthesized a GPI anchor mimetic (GPIm), which we have covalently coupled to a genetically engineered cysteine residue at the C-terminus of recombinant PrP. The lipid anchor places the protein at the same distance from the membrane as does the naturally occurring GPI anchor. We demonstrate that PrP coupled to GPIm (PrP,GPIm) inserts into model lipid membranes and that structural information can be obtained from this membrane-anchored PrP. We show that the structure of PrP,GPIm reconstituted in phosphatidylcholine and raft membranes resembles that of PrP, without a GPI anchor, in solution. The results provide experimental evidence in support of previous suggestions that NMR structures of soluble, anchor-free forms of PrP represent the structure of cellular, membrane-anchored PrP. The availability of a lipid-anchored construct of PrP provides a unique model to investigate the effects of different lipid environments on the structure and conversion mechanisms of PrP. [source]

Pathogen safety of manufacturing processes for biological products: special emphasis on KOGENATE® Bayer

HAEMOPHILIA, Issue 2002
D. C. Lee
Summary., Manufacturers of human therapeutic proteins derived from biological sources continuously strive to improve the pathogen safety profiles of these products. Efforts to improve pathogen safety margins for these biological products are directed towards several areas within the manufacturing processes including: (a) sourcing and screening of raw materials (b) determining the potential for manufacturing processes to reduce pathogen titres, and (c) incorporating methods designed specifically to remove or inactivate contaminating pathogens. Methods that could potentially reduce pathogen titres are a major focus for many manufacturers. In general, these methods are grouped into two categories, pathogen clearance and pathogen inactivation. Assessments are performed on small-scale, laboratory simulations of the manufacturing process of interest that are spiked with a known amount of a selected pathogen. These studies provide estimates of the potential for a process step to remove or inactivate a particular pathogen. There are several pathogen clearance/inactivation methods that are inherent in manufacturing processes, however, some methods are intentionally incorporated into manufacturing for the sole purpose of reducing putative pathogen titres. Not only are well-known pathogens such as viruses targeted, but also suspected pathogens such as those associated with the transmissible spongiform encephalopathies (TSEs). The production processes for the isolation of several biological products, including recombinant KOGENATE® Bayer (Kogenate®FS), have been evaluated for the ability to reduce pathogen titres and/or have been designed to incorporate methods for reducing potential pathogen safety risks. Several processing steps with the potential to reduce pathogen titres have been identified. [source]

Is major depressive disorder a metabolic encephalopathy?

HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 5 2008
Brian H Harvey
Abstract Metabolic encephalopathy is an acute disturbance in cellular metabolism in the brain evoked by conditions of hypoxia, hypoglycaemia, oxidative stress and/or inflammation. It usually develops acutely or subacutely and is reversible if the systemic disorder is treated. If left untreated, however, metabolic encephalopathy may result in secondary structural damage to the brain. Most encephalopathies are present with neuropsychiatric symptoms, one in particular being depression. However, mood disorders are often co-morbid with cardiovascular, liver, kidney and endocrine disorders, while increasing evidence concurs that depression involves inflammatory and neurodegenerative processes. This would suggest that metabolic disturbances resembling encephalopathy may underscore the basic neuropathology of depression at a far deeper level than currently realized. Viewing depression as a form of encephalopathy, and exploiting knowledge gleaned from our understanding of the neurochemistry and treatment of metabolic encephalopathy, may assist in our understanding of the neurobiology of depression, but also in realizing new ideas in the pharmacotherapy of mood disorders. Copyright © 2008 John Wiley & Sons, Ltd. [source]

New molecular markers of early and progressive CJD brain infection

JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2004
Zhi Yun Lu
Abstract Transmissible spongiform encephalopathies (TSEs), including human Creutzfeldt,Jakob disease (CJD), are caused by a related group of infectious agents that can be transmitted to many mammalian species. Because the infectious component of TSE agents has not been identified, we examined myeloid cell linked inflammatory pathways to find if they were activated early in CJD infection. We here identify a specific set of transcripts in CJD infected mouse brains that define early and later stages of progressive disease. Serum amyloid A3 and L-selectin mRNAs were elevated as early as 20 days after intracerebral inoculation. Transcripts of myeloid cell recruitment factors such as MIP-1,, MIP-1,, and MCP1, as well as IL1, and TNF, were upregulated >10 fold between 30 and 40 days, well before prion protein (PrP) abnormalities that begin only after 80 days. At later stages of symptomatic neurodegenerative disease (100,110 days), a selected set of transcripts rose by as much as 100 fold. In contrast, normal brain inoculated controls showed no similar sequential changes. In sum, rapid and simple PCR tests defined progressive stages of CJD brain infection. These markers may also facilitate early diagnosis of CJD in accessible peripheral tissues such as spleen and blood. Because some TSE strains can differentially target particular cell types such as microglia, several of these molecular changes may also distinguish specific agent strains. The many host responses to the CJD agent challenge the assumption that the immune system does not recognize TSE infections because these agents are composed only of the host's own PrP. © 2004 Wiley-Liss, Inc. [source]

Variant Creutzfeldt-Jakob disease: An unfolding epidemic of misfolded proteins

JOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 6 2002
P Horby
Abstract: Variant Creutzfeldt-Jakob disease (vCJD) is an emerging infectious disease believed to be the human manifestation of bovine spongiform encephalopathy (BSE). Variant CJD belongs to a family of human and animal diseases called transmissible spongiform encephalopathies (TSE). The pathogenesis of TSE is not fully understood, but a modified form of a normal cellular protein plays a central role. Current measures to control vCJD aim to prevent transmission of the infectious agent from animals to humans through food or pharmaceutical products and to prevent transmission from person to person via medical interventions. The anticipated development of preclinical diagnostic tests and treatments for vCJD will create new control options and difficult choices. [source]

Myiasis as a risk factor for prion diseases in humans

JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 9 2006
O Lupi
Abstract Prion diseases are transmissible spongiform encephalopathies of humans and animals. The oral route is clearly associated with some prion diseases, according to the dissemination of bovine spongiform encephalopathy (BSE or mad cow disease) in cattle and kuru in humans. However, other prion diseases such as scrapie (in sheep) and chronic wasting disease (CWD) (in cervids) cannot be explained in this way and are probably more associated with a pattern of horizontal transmission in both domestic and wild animals. The skin and mucous membranes are a potential target for prion infections because keratinocytes and lymphocytes are susceptible to the abnormal infective isoform of the prion protein. Iatrogenic transmission of Creutzfeldt,Jakob disease (CJD) was also recognized after corneal transplants in humans and scrapie was successfully transmitted to mice after ocular instillation of infected brain tissue, confirming that these new routes could also be important in prion infections. Some ectoparasites have been proven to harbour prion rods in laboratory experiments. Prion rods were identified in both fly larvae and pupae; adult flies are also able to express prion proteins. The most common causes of myiasis in cattle and sheep, closely related animals with previous prion infections, are Hypoderma bovis and Oestrus ovis, respectively. Both species of flies present a life cycle very different from human myiasis, as they have a long contact with neurological structures, such as spinal canal and epidural fat, which are potentially rich in prion rods. Ophthalmomyiases in humans is commonly caused by both species of fly larvae worldwide, providing almost direct contact with the central nervous system (CNS). The high expression of the prion protein on the skin and mucosa and the severity of the inflammatory response to the larvae could readily increase the efficiency of transmission of prions in both animals and humans. [source]

14-3-3 protein in the CSF of inflammatory peripheral neuropathies

JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2004
A Bersano
14-3-3 proteins are a highly conserved protein family of unknown function, although some authors suggested a role in cellular proliferation and differentiation, neurotransmitters biosynthesis and apoptosis. The expression of these proteins increases during development, in particular, in large projection neurons such as spinal motor neurons. Recently the protein was described in cerebrospinal fluid (CSF) of patients with spongiform encephalopathies, in particular Creutzfeld-Jacob disease, where the protein is considered a highly sensitive and specific marker. 14-3-3 protein has been also detected in CSF of other prion-unrelated dementias and other neurodegenerative (Parkinson disease, stroke and paraneoplastic syndromes) and inflammatory diseases like Multiple Sclerosis. The aim of our study was to evaluate whether the 14-3-3 protein is also present in the CSF of peripheral nervous system diseases. We studied by Western Blot the CSF of 120 patients including 38 with Guillain-Barré syndrome (GBS), 23 with chronic inflammatory demyelinating polyneuropathy (CIDP), 12 with multifocal motor neuropathies (MMN), 20 motor neuron disease (MND), 8 paraneoplastic syndrome, 14 other neuropathies or radiculopathies (OPN), and 5 normal subjects (NC). We found the 14-3-3 protein in the CSF of 21 (55%) patients with GBS, 13 (56%) with CIDP, 1 (5%) with MND, 3 (21%) with OPN and none with paraneoplastic syndrome, MMN or NC. Our results reveal that 14-3-3 protein can be detected not only in central but also in peripheral nervous system diseases where it is significantly associated (p < 0.0001) with GBS and CIDP. [source]