Third case of vCJD reported in the United States

A clinical diagnosis of variant Creutzfeldt Jakob Disease was confirmed after brain biopsy investigations in a United States resident and reported in November.

The expanding universe of prion diseases

Prions cause fatal and transmissible neurodegenerative disease. These etiological infectious agents are formed in greater part from a misfolded cell-surface protein called PrP(C). Several mammalian species are affected by the diseases, and in the case of "mad cow disease" (BSE) the agent has a tropism for humans, with negative consequences for agribusiness and public health. Unfortunately, the known universe of prion diseases is expanding. At least four novel prion diseases--including human diseases variant Creutzfeldt-Jakob disease (vCJD) and sporadic fatal insomnia (sFI), bovine amyloidotic spongiform encephalopathy (BASE), and Nor98 of sheep--have been identified in the last ten years, and chronic wasting disease (CWD) of North American deer (Odocoileus Specis) and Rocky Mountain elk (Cervus elaphus nelsoni) is undergoing a dramatic spread across North America. While amplification (BSE) and dissemination (CWD, commercial sourcing of cervids from the wild and movement of farmed elk) can be attributed to human activity, the origins of emergent prion diseases cannot always be laid at the door of humankind. Instead, the continued appearance of new outbreaks in the form of "sporadic" disease may be an inevitable outcome in a situation where the replicating pathogen is host-encoded.

Classification of surgical procedures for epidemiologic assessment of sporadic Creutzfeldt-Jakob disease transmission by surgery

BACKGROUND

In this preparatory phase of a case-control study, we propose and evaluate a new tool for classifying surgical procedures (SPs) in categories useful for epidemiologic research on surgical transmission of sporadic Creutzfeldt-Jakob disease (sCJD).

METHODS

All SPs reported to the Swedish National Hospital Discharge Registry in the period 1974-2002, and undergone by 212 Swedish patients with registered diagnosis of CJD at death, hospital discharge or notification, in the period 1987-2002, 1060 age-, sex- and residence-matched controls and 1340 randomly chosen population controls, were reclassified into one of six categories of hypothetical transmission risk level. For that purpose the following two attributes were used: non-disposable instruments involved; and highest assigned ad-hoc risk level for four tissues or anatomical structures contacting such instruments.

RESULTS

A total of 1170 different SP codes were reclassified as follows: 3.1% in the high-risk, 59.1% in the lower-risk, 24.4% in the lowest-risk, and 2.1% in the no-risk groups, with 11.3% procedures negatively defined by rubric as "other than..." being assigned to two spurious diluted-high and diluted-lower risk categories. The high-risk group mainly comprised neurosurgical (53%) and ophthalmic (39%) procedures. Sensitivity of neurosurgery and of ophthalmic surgery excluding neurosurgery, for the high- and diluted-high risk vs. other categories was 46% and 84%, while specificity was 98% and 95%, respectively. Sensitivity analysis based on these indices revealed that non-significant odds ratio effects of 1.4 and 1.3 for neurosurgery and ophthalmic surgery corresponded to statistically significant values of 5.1 after reclassification.

CONCLUSIONS

This classification might contribute to quantify effects masked by use of body-system SP-categories in case-control studies on sCJD transmission by surgery.

Increased asymmetric pulvinar magnetic resonance imaging signals in Creutzfeldt-Jakob disease with florid plaques following a cadaveric dura mater graft

A 9-year-old Japanese girl received a cadaveric dura mater graft during surgery following a head injury with brain contusion. She continued to do well, but when she became 19-years-old, she gradually showed a violent character and was treated in a psychiatric hospital. Another 6 years later, 200 months after the procedure, she developed a progressive gait ataxia, which subsequently led to her death within 10 months of onset. An autopsy showed she had CJD. This patient represents an atypical case of dura-associated CJD (dCJD) with unusual clinicopathological features including the late occurrence of myoclonus, an absence of periodic synchronous discharges in the electroencephalogram, and the presence of widespread florid plaques. However, our detection of an asymmetrical increase in the MRI-derived images of pulvinar nuclei has not been previously observed in other atypical cases of dCJD. Because atypical dCJD cases share several clinicopathological features with those of vCJD, and because asymmetrical hyperintense signals in the pulvinar have been observed in some neuropathologically confirmed vCJD cases, we had some difficulty in a differential diagnosis between atypical dCJD and vCJD. This is the first atypical dCJD case showing a pulvinar high signal compared with all other basal ganglia on MRI.

Pathogenesis and prevalence of variant Creutzfeldt-Jakob disease

In the late 1980s and early 1990s, there was widespread exposure of the UK population to bovine spongiform encephalopathy (BSE)-contaminated food products, which has led to over 150 deaths from variant Creutzfeldt-Jakob disease (vCJD). Although the pathogenesis in humans is not fully understood, data from animal models and, to a lesser extent, patients with vCJD suggest that oral exposure to BSE is rapidly followed by accumulation of PrP(res) in gut-associated lymphoid tissue, then, after haematogenous spread, throughout the lymphoreticular system. Spread to the central nervous system may not occur for several years, but blood from individuals in the pre-clinical phase appears to be able to transmit disease. The incidence of vCJD has remained low and is in decline, but it is known from iatrogenic CJD and kuru that human prion disease can have incubation periods of up to 40 years. Cases of vCJD are therefore likely to occur for many more years and alternative phenotypes may develop in individuals with different PRNP genotypes to those seen to date. Studies in transgenic mice have shown that sub-clinical infection is frequent following oral exposure to BSE and a study looking at the accumulation of PrP in anonymized human lymphoid tissue samples found positive cases. There are likely to be a number of asymptomatic 'carriers' of disease within the UK and although it is unclear whether these individuals will develop clinical disease, there is a potential for iatrogenic spread to others. These uncertainties highlight the importance of developing a reliable blood test for vCJD and the continued need for surveillance.

Human growth hormone-related iatrogenic Creutzfeldt-Jakob disease with abnormal imaging

BACKGROUND

Although more than 160 cases of iatrogenic Creutzfeldt-Jakob disease (iCJD) from human growth hormone (hGH) treatment have been documented, to our knowledge abnormal cerebellar findings on magnetic resonance imaging (MRI) have not been reported.

OBJECTIVE

To report a case of hGH-related iCJD with abnormal cerebellar MRI findings on fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted MRI (DWI).

DESIGN

Case report.

SETTING

Outpatient neurology clinic at a university medical center.

PATIENT

A 33-year old man who had subacute gait ataxia and blurred vision.

RESULTS

Beginning 19 years prior, this patient had received cadaveric pituitary-derived hGH treatment for at least 5 years. Magnetic resonance imaging revealed FLAIR and DWI abnormalities, particularly in the cerebellum. He died 7 months after disease onset of autopsy-confirmed iCJD. Pathological changes corresponded largely to MRI findings.

CONCLUSIONS

To our knowledge, this is the first case of hGH-related iCJD with FLAIR and DWI abnormalities within the cerebellum. As symptoms referable to the cerebellum occur early in iCJD, it suggests that these MRI sequences may allow earlier diagnosis of this form of prion disease.

Variant CJD (vCJD) and bovine spongiform encephalopathy (BSE): 10 and 20 years on: part 1

From 1986 more than 184,000 cattle in the UK and islands (of which >1,880 have been detected by active surveillance using rapid tests) and approaching 5,500 elsewhere have been confirmed with BSE. The original 1988 ban on the use of ruminant-derived protein in ruminant feed has been upgraded and now prohibits the use of any processed animal protein in feed for any farmed food animal. As a result of rigorous enforcement this reinforced ban is now regarded as fully effective from 1 Aug. 1996. Reasons are given for the substantial slippage that occurred initially and for the small but diminishing number of cases that have occurred in cattle born after 1 Aug. 1996. The 1989 offal ban, initially introduced to protect public health, has likewise been progressively strengthened and since 1995 has been effectively enforced by the Meat Hygiene Service, thus protecting the consumer. It is now extended as the specified risk material (SRM) ban throughout the EU. BSE continues to decline towards elimination in the UK and is being dealt with effectively in other Member States of the European Union (EU) and Switzerland with an extensive (and very expensive) range of edicts. The improving situation in the EU has encouraged the EC to draft a TSE Roadmap outlining possible reduction in control measures whilst still protecting the consumer. The situation on a global basis still causes concern as, although cases are less frequent than in the UK, surveillance, legislation and enforcement are not clearly as extensive and effective as in the EU. The risk of primary transmission of BSE to man from cattle to cause variant CJD (vCJD) is examined with reference to up-to-date assessments of bovine tissue infectivity and is now regarded as unlikely in the EU and Switzerland.

Creutzfeldt-Jakob disease: Australian surveillance update to December 2005

Australia-wide prospective surveillance of human transmissible spongiform encephalopathies (TSEs) has been conducted by the Australian National Creutzfeldt-Jakob Disease Registry (ANCJDR) since October 1993. In addition, the Registry retrospectively ascertained TSE cases within Australia from 1970. Referrals of all suspect cases of human prion diseases or TSEs are investigated by the ANCJDR and include Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome, fatal familial insomnia and variant CJD. This semi-annual progressive update presents epidemiological findings of the ANCJDR based on Australian data obtained for the period 1970 to 31 December 2005.

Variant CJD (vCJD) and bovine spongiform encephalopathy (BSE): 10 and 20 years on: part 2

Up until February 2006, variant CJD (vCJD), the human disease associated with transmission of BSE from cattle, has been confirmed in 160 patients resident in the UK and 28 elsewhere, some of whom have never visited the UK. Cases have been reported in France (16 cases), Ireland (3), USA (2), Canada, Italy, Japan, The Netherlands, Portugal, Saudi Arabia and Spain (1 each). The presumed main period of hazard for ingestion of the BSE agent in bovine products in the UK is 1984-89, or perhaps up to 1995-6 but at a reduced level. Debated incubation periods for vCJD are discussed, with special reference to the wide, but currently reducing, range of predicted further primary cases in the UK. The primary disease seems to be preferentially acquired by, and expressed in, relatively young people. All but one of the British cases examined so far were homozygous for methionine at the polymorphic codon 129 of the prion protein PRNP gene. Tests of appendix specimens from large numbers of otherwise normal subjects at the time of appendicectomy have revealed lymphoreticular accumulations of PrP(Sc) in a few samples. Furthermore, three patients who died of vCJD had appendices removed by appendicectomy whilst healthy. Two of these appendices were retrospectively shown to be positive for PrP(Sc) and one removed 10 years before clinical onset was negative. This has led to worries regarding the possibility of pre-clinical or sub-clinical prion-associated disease in an unknown proportion of the population. To date, there has been no known association of primary vCJD with occupation, medicines, immunising agents, gelatine, or surgery (including the use of catgut sutures), or exposure to bovine products other than by ingestion. There is much concern that human-to-human (secondary) vCJD infection is transferred by blood transfusion. A possible risk is also perceived from infected blood products, human organs and tissues, or via contaminated surgical instruments or devices though, so far as is known, no cases have yet arisen in this way. Steps have been taken to reduce the risks and much research is in hand in this field. Continued TSE surveillance, the maintenance of adequate preventive controls, attention to possible parenteral challenges, and further research studies are of paramount importance.

[Functions of the thalamus in psychiatry: the relationship between the thalamus and schizophrenia]

The thalamus involves two electrophysiological systems of the specific projection system and the non-specific projection system. The electrical stimulation of the former induces the augmenting response in the cerebral cortex and the same of the latter induces the recruiting response in the cortex. The non-specific projection system is also known as the diffuse thalamo- cortical projection system and it is concerned with the maintenance mechanism of consciousness such as sleep and wakefulness. The thalamus is concerned in the higher nervous functions such as language, cognition, memory and intelligence. Severe nerve cell loss with proliferation of hypertrophic astroglia was found in the association nuclei and sensory relay nuclei in the thalami of patients suffering from Creutzfeldt-Jakob disease. In the brain imaging study, volume reduction of the thalamus, especially of dorsomedial nuclei, degradation of glucose metabolism were observed in the thalami of patients with schizophrenia. Carlsson considered schizophrenia as a subcortical neurotransmitter imbalance syndrome based on the hypothesis of a thalamic filter. Andreasen defined schizophrenia as a misconnection syndrome or cognitive dysmetria induced by dysfunction of the cortico-cerebellar-thalamic-cortical circuit (CCTCC).

[Cerebral magnetic resonance imaging in iatrogenic Creutzfeldt-Jacob disease]

INTRODUCTION

We describe here the cerebral cerebral magnetic resonance (MRI) abnormalities observed in a case of iatrogenic Creutzfeldt-Jacob disease (CD).

CASE

A 37 year-old man had been treated for pituitary dwarfism during adolescence with contaminated growth hormone. Neurological symptoms nearly two decades later suggested CJD. Cerebral MRI nine months after the onset of symptoms showed hypersignals similar to those observed in variant CJD (pulvinar sign). The diagnosis of CJD was confirmed by post-mortem examination.

DISCUSSION

To our knowledge, this is the first case in which MRI revealed iatrogenic CD. The aspects are similar to those described for variant CJD.

Creutzfeldt-Jakob disease acquired via a dural graft: failure of therapy with quinacrine and chlorpromazine

BACKGROUND

Accidental transmission of Creutzfeldt-Jakob disease (CJD) has been reported after neurosurgical interventions, use of intracerebral electrodes, corneal transplants, and after the administration of human-derived hormones. Acquired CJD has also been documented after dural grafting with tissues of human cadaver origin. At present, quinacrine and chlorpromazine are being investigated for the treatment of sporadic CJD, with the hope of offering an effective treatment of an otherwise fatal disease. Our objective was to report a case of iatrogenic CJD occurring 18 years after the implant of a dural graft of human origin and to inform on the results of the treatment with quinacrine and chlorpromazine.

CASE DESCRIPTION

In 1984, a 46-year-old woman was given a Lyodura graft for decompression of Chiari I malformation and syringomyelia. The patient was diagnosed with CJD in 2002. In view of the scarce options for treatment of CJD and after reviewing the current literature, the patient was treated with quinacrine and chlorpromazine. She showed no clinical improvement and died 6 months after hospital admission. The iatrogenic origin of the disease in this patient is supported by the clinical features, laboratory data, and findings from the brain necropsy.

CONCLUSIONS

Patients who have received a dural graft of cadaveric origin may be at risk for developing CJD after very prolonged incubation periods. Treatment with quinacrine and chlorpromazine for acquired CJD was ineffective in our patient. A clinical trial on the use of antiprion agents is warranted.

Creutzfeldt-Jakob disease

Cruetzfeldt-Jakob disease is a prion protein disease causing a transmissible, subacute, fatal neurodegenerative disease characterized by a spongiform encephalopathy. Though rare, ever since Pruisner described the pathogenesis in 1982, this disease kept the clinicians as well as biologists spellbound, because of its distinct clinical picture and the novel mechanism of transmission. There was a further quantum leap in the interest in the disease with the establishment of its new clinical variant, the so called 'mad cow disease' in the late 1990s and had led to more stringent measures to ensure the quality of cattle-feeds and cattle-derived food products. The sporadic genetic variants, the commonest form of the disease, continue to challenge the genetic scientists. Advances in neuroimaging, cerebrospinal fluid marker proteins and genetic linkage studies now offer excellent diagnostic methods, while advances in therapeutic medicine which use products from cadaveric extracts such as growth hormone for treatment of hypopituitarism, dural grafts for neurosurgical procedures and cornea for transplantation etc. have thrown new challenges in controlling this serious disease.

Cerebrospinal fluid biomarkers in Creutzfeldt–Jakob disease

Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative disorder. Since the emergence of variant CJD (vCJD) vigilance concerning the disease's incidence has increased and the interest in accurate in vivo diagnosis has augmented. So far, a large number of biomarkers has been investigated as aid in the differential diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) and vCJD. These include, among others, neuron-specific enolase (NSE), microtubuli associated protein Tau, S-100beta, amyloid-beta (Abeta(1-42)) and the 14-3-3 protein. Multiple studies have confirmed that CSF detection of 14-3-3 protein by Western blot was the best single biomarker for sCJD with an average sensitivity and specificity of 92%. Also, in genetic and iatrogenic CJD (iCJD) patients with an average disease duration of less than 1 year, 14-3-3 is the best differential biomarker. Unfortunately, the 14-3-3 protein has a lower sensitivity if the disease duration exceeds beyond 1 year in both sporadic CJD and other CJD types (vCJD, and specific genetic or iatrogenic CJD types).

Human and animal spongiform encephalopathies are the result of chronic autoimmune attack in the CNS: a novel medical theory supported by overwhelming experimental evidence

Spongiform encephalopathies, also called "prion diseases", are fatal degenerative diseases of the central nervous system which can occur in animals (such as the "mad cow disease" in cattle) and also in humans. This paper presents a novel medical theory concerning the pathogenic mechanisms for various human and animal spongiform encephalopathies. It is hypothesized that various forms of prion diseases are essentially autoimmune diseases, resulting from chronic autoimmune attack of the central nervous system. A key step in the pathogenic process leading towards the development of spongiform encephalopathies involves the production of specific autoimmune antibodies against the disease-causing prion protein (PrPsc) and possibly other immunogenic macromolecules present in the brain. As precisely explained in this paper, the autoimmune antibodies produced against PrPsc are responsible for the conversion of the normal cellular prion protein (PrPc) to PrPsc, for the accumulation of PrPsc in the brain and other peripheral tissues, and also for the initiation of an antibody-mediated chronic autoimmune attack of the central nervous system neurons, which would contribute to the development of characteristic pathological changes and clinical symptoms associated with spongiform encephalopathies. The validity and correctness of the proposed theory is supported by an overwhelming body of experimental observations that are scattered in the biomedical literature. In addition, the theory also offers practical new strategies for early diagnosis, treatment, and prevention of various human and animal prion diseases.

Transmissible spongiform encephalopathy risk assessment: the UK experience

Transmissible spongiform encephalopathy (TSE) risk assessments undertaken in the United Kingdom have mainly had the objective of determining the risks posed to humans from exposure to the causal agents associated with bovine spongiform encephalopathy (BSE) and variant Creutzfeld-Jakob disease (vCJD). In this article, I examine 19 of these risk assessments published to date and consider how their results might be influenced by underlying model assumptions and methodology. Three separate aspects common to all the assessments are infective load estimation, exposure pathway identification, and risk estimation. These are each discussed in detail.

Transmission barriers for bovine, ovine, and human prions in transgenic mice

Transgenic (Tg) mice expressing full-length bovine prion protein (BoPrP) serially propagate bovine spongiform encephalopathy (BSE) prions without posing a transmission barrier. These mice also posed no transmission barrier for Suffolk sheep scrapie prions, suggesting that cattle may be highly susceptible to some sheep scrapie strains. Tg(BoPrP) mice were also found to be susceptible to prions from humans with variant Creutzfeldt-Jakob disease (CJD); on second passage in Tg(BoPrP) mice, the incubation times shortened by 30 to 40 days. In contrast, Tg(BoPrP) mice were not susceptible to sporadic, familial, or iatrogenic CJD prions. While the conformational stabilities of bovine-derived and Tg(BoPrP)-passaged BSE prions were similar, the stability of sheep scrapie prions was higher than that found for the BSE prions but lower if the scrapie prions were passaged in Tg(BoPrP) mice. Our findings suggest that BSE prions did not arise from a sheep scrapie strain like the one described here; rather, BSE prions may have arisen spontaneously in a cow or by passage of a scrapie strain that maintains its stability upon passage in cattle. It may be possible to distinguish BSE prions from scrapie strains in sheep by combining conformational stability studies with studies using novel Tg mice expressing a chimeric mouse-BoPrP gene. Single-amino-acid substitutions in chimeric PrP transgenes produced profound changes in incubation times that allowed us to distinguish prions causing BSE from those causing scrapie.

[Iatrogenic neurological disorders in old people: a review]

Aged people are frequently the victims of iatrogenic diseases, especially adverse effects of drugs since they are affected by many age-related diseases and are given many drugs. Geriatric medicine in Japan has a bitter history of having produced many victims by adverse effects of cerebral vasodilators and cerebral stimulants; they included parkinsonism and depression induced by flunarizine and cinnarizine, and Reye-like encephalopathy induced by calcium hopantenate. Parkinsonism induced by sulpiride, tiapride, metoclopramide or atypical anti-psychotics, dyskinesia induced by anti-parkinsonian drugs or anti-psychotics, and psychotic symptoms induced by anti-parkinsonian drugs, anti-cholinergic drugs, anti-depressants or histamine H2 antagonists are still very common. Wernicke encephalopathy caused by intravenous glucose infusion without thiamine, central pontine myelinolysis by too rapid correction of hyponatremia are important though infrequent. Iatrogenic Creutzfeldt-Jakob disease by dura grafts is a warning against the easy use of medical materials produced with human organs or blood. Iatrogenic diseases are preventable, and geriatricians have to pay attention to the information on adverse effects of drugs and medical materials and carefully observe the early signs of iatrogenic diseases.

Type 1 and type 2 human PrPSc have different aggregation sizes in methionine homozygotes with sporadic, iatrogenic and variant Creutzfeldt-Jakob disease

In Creutzfeldt-Jakob disease (CJD), the type (type 1 or 2) of abnormal isoform of the prion protein (PrP(Sc)) in the brain and the genotype at codon 129 of the PrP gene are major determinants of clinicopathological phenotype. Little is known about the difference in biochemical properties between the two types of PrP(Sc), except for the different proteinase K cleavage sites. To investigate the size of aggregates formed by PrP(Sc) types 1 and 2, brain homogenates from various cases of CJD with the same genotype (homozygous for methionine at codon 129) were passed through filters with a mean pore size of 72+/-4 nm. Type 2 PrP(Sc) was efficiently removed from the filtrates by the filters, in contrast to type 1. Even type 2 PrP(Sc) from a patient without amyloid plaques was removed more efficiently than type 1 from patients with amyloid plaques. These results indicate that type 2 PrP(Sc) has a larger aggregation size than type 1, irrespective of the existence of amyloid plaques.

Risks of transmission of variant Creutzfeldt-Jakob disease by blood transfusion

Variant Creutzfeldt-Jakob disease (vCJD) was first identified in 1996 in the UK, and results from human exposure to the bovine spongiform encephalopathy (BSE) agent. vCJD has subsequently been identified in 10 additional countries, and numbers continue to increase in the UK. Unlike other human prion diseases, infectivity and the disease-associated form of the prion protein are readily detected in lymphoid tissues in vCJD. In experimental BSE infection in a sheep model, infectivity has been transmitted by blood transfusion from asymptomatic infected animals to normal recipient animals, indicating that infectivity is present in blood during the incubation period. Recently, two cases of apparent iatrogenic vCJD infection by blood transfusion from asymptomatic donors who subsequently died from vCJD have been reported from the UK. The first case resulted in clinical illness identical to other cases of vCJD, while the second case was an asymptomatic infection detected at autopsy. Sensitive means of detection of disease-associated prion protein in the blood are required in order to be employed for screening purposes, both individually at the time of blood donation, and to help ascertain future numbers of vCJD cases in the UK and beyond.

Risk factors for variant Creutzfeldt-Jakob disease: A case-control study

OBJECTIVE

To investigate the potential risk factors for variant Creutzfeldt-Jakob disease (VCJD) in the United Kingdom.

METHODS

Definite and probable vCJD cases (n = 136) were residing in Great Britain at disease onset, and were referred between May 1995 and November 2003. Control subjects (n = 922) were recruited between 2002 and 2003, from 100 randomly selected geographical clusters sampled to represent the geographical distribution of vCJD.

RESULTS

Reported frequent consumption of beef and beef products thought likely to contain mechanically recovered or head meat, or both, including burgers and meat pies, was associated with increased risk for vCJD, as was reported frequent chicken consumption. Surgical operations were generally similarly reported for cases and control subjects, with the exception of a small group of minor operations, possibly attributable to underreporting in control subjects. Cases and control subjects had similar reported occupational histories and exposure to animals.

INTERPRETATION

These findings are consistent with dietary exposure to contaminated beef products being the main route of infection of vCJD, but recall bias cannot be excluded. There was no convincing evidence of increased risk through medical, surgical, or occupational exposure or exposure to animals.

Thinking the unthinkable: Alzheimer’s, Creutzfeldt–Jakob and Mad Cow disease: the age-related reemergence of virulent, foodborne, bovine tuberculosis or losing your mind for the sake of a shake or burger

The possibility of the age-related reemergence of foodborne Mycobacterium bovis (bovine tuberculosis) as a vector for Creutzfeldt-Jakob Disease (CJD or human Mad Cow Disease) and Mad Cow disease itself is real. The CDC reported last May of an outbreak of CJD linked to the consumption of meat contaminated "with the agent causing" bovine spongiform encephalopathy (BSE) in a New Jersey racetrack between the time frame 1995-2004. In the opinion of experts, ample justification exists for considering a similar pathogenesis for Alzheimer's, Creutzfeldt-Jakob and the other spongiform encephalopathies such as Mad Cow disease. In fact, Creutzfeldt-Jakob and Alzheimer's often coexist and at this point are thought to differ merely by time-dependent physical changes. A recent study links up to 13% of all "Alzheimer's" victims as really having Creutzfeldt-Jakob disease. Bovine tuberculosis, which includes Mycobacterium bovis and M. avium-intracellulare or paratuberculosis, is and has always been the most prevalent threat to the cattle industry, and the USDA reports that between 20% and 40% of US dairy herds are infected with paratuberculosis alone. The health risk for milk tainted with M. bovis has been known for decades and there was a time not so long ago when "tuberculin-tested" was printed on every milk container. Schliesser stated that meat from tuberculous animals may also constitute a significant risk of infection. At the turn of the 20th century 25% of the many US deaths from TB in adults were caused by M. bovis. Dairy products aside, when past and present meat consumption are factored in, there is three times the risk of developing Alzheimer's in meat eaters as opposed to vegetarians. The investigation into the causal trail for Creutzfeldt-Jakob, indistinguishable from Alzheimer's except for its shorter, lethal course might have grown cold where it not for Roel's and others who linked mad cow in cattle with M. bovis and related paratuberculosis on clinical, pathologic and epidemiological grounds. The southwest of the UK, the very cradle of British BSE and CJD outbreaks, saw an exponential increase in bovine tuberculosis just prior to it's spongiform outbreaks. All of this brings up the unthinkable: that Alzheimer's, Cruetzfeldt-Jackob, and Mad Cow Disease might just be caused by eating the meat or dairy in consumer products or feed. It is only appropriate therefore to explore the role of bovine TB and the atypical mycobacteria in Alzheimer's, JCD and Mad Cow disease and develop better serological surveillance for these pathogens.

Allogeneic red blood cell transfusions: efficacy, risks, alternatives and indications

Careful assessment of risks and benefits has to precede each decision on allogeneic red blood cell (RBC) transfusion. Currently, a number of key issues in transfusion medicine are highly controversial, most importantly the influence of different transfusion thresholds on clinical outcome. The aim of this article is to review current evidence on blood transfusions, to highlight 'hot topics' with respect to efficacy, outcome and risks, and to provide the reader with transfusion guidelines. In addition, a brief synopsis of transfusion alternatives will be given. Based on up-to-date information of current evidence, together with clinical knowledge and experience, the physician will be able to make transfusion decisions that bear the lowest risk for the patient.

The modern landscape of transfusion-related iatrogenic Creutzfeldt–Jakob disease and blood screening tests

The idea that blood in naturally occurring transmissible spongiform encephalopathies is not infectious has imploded in the face of recent transmissions from the blood of naturally occurring scrapie in sheep and of variant Creutzfeldt-Jakob disease in humans. Although donor exclusion criteria ensure that the number of any further iatrogenic cases will be small, the risk of future blood-borne disease transmissions could be entirely eliminated by a diagnostic preclinical screening test. A variety of methodological approaches to blood testing are under development, with different levels of success, but no method has yet achieved the critical goal of discriminating transmissible spongiform encephalopathy-infected from healthy uninfected humans.

Epidemiological evidence of higher susceptibility to vCJD in the young

Background

The strikingly young age of new variant Creutzfeldt-Jacob disease (vCJD) cases remains unexplained. Age dependent susceptibility to infection has been put forward, but differential dietary exposure to contaminated food products in the UK population according to age and sex during the bovine spongiform encephalopathy (BSE) epidemic may provide a simpler explanation.

Methods

Using recently published estimates of dietary exposure in mathematical models of the epidemiology of the new variant Creutzfeldt Jacob disease (vCJD), we examine whether the age characteristics of vCJD cases may be reproduced.

Results

The susceptibility/exposure risk function has likely peaked in adolescents and was followed by a sharp decrease with age, evocative of the profile of exposure to bovine material consumption according to age. However, assuming that the risk of contamination was proportional to exposure, with no age dependent susceptibility, the model failed to reproduce the observed age characteristics of the vCJD cases: The predicted cumulated proportion of cases over 40 years was 48%, in strong disagreement with the observed 10%. Incorporating age dependent susceptibility led to a cumulated proportion of cases over 40 years old of 12%.

Conclusions

This analysis provides evidence that differential dietary exposure alone fails to explain the pattern of age in vCJD cases. Decreasing age related susceptibility is required to reproduce the characteristics of the age distribution of vCJD cases.

Bovine spongiform encephalopathy and Creutzfeldt-Jakob disease: facts and uncertainties underlying the causal link between animal and human diseases

Following an outbreak of bovine spongiform encephalopathy (BSE) in dairy cows in the United Kingdom (UK), 153 definite and probable human cases of new variant Creutzfeldt-Jakob disease (nvCJD) have been reported, almost exclusively in the UK. Although exposure to the BSE agent is the most plausible interpretation for the occurrence of nvCJD, the causal link between the BSE prion and nvCJD is still debated. This review discusses the pros and cons of nvCJD as a separate nosographic entity, the scientific basis for a correlation between BSE and nvCJD, the validity of the current diagnostic criteria for CJD and nvCJD, the contribution of epidemiology to the detection of a causal relation between BSE and nvCJD, and the present and future directions of the epidemiological research on BSE, CJD and nvCJD.

Methionine 129 Variant of Human Prion Protein Oligomerizes More Rapidly than the Valine 129 Variant

The human PrP gene (PRNP) has two common alleles that encode either methionine or valine at codon 129. This polymorphism modulates disease susceptibility and phenotype of human transmissible spongiform encyphalopathies, but the molecular mechanism by which these effects are mediated remains unclear. Here, we compared the misfolding pathway that leads to the formation of beta-sheet-rich oligomeric isoforms of the methionine 129 variant of PrP to that of the valine 129 variant. We provide evidence for differences in the folding behavior between the two variants at the early stages of oligomer formation. We show that Met(129) has a higher propensity to form beta-sheet-rich oligomers, whereas Val(129) has a higher tendency to fold into alpha-helical-rich monomers. An equimolar mixture of both variants displayed an intermidate folding behavior. We show that the oligomers of both variants are initially a mixture of alpha- and beta-rich conformers that evolve with time to an increasingly homogeneous beta-rich form. This maturation process, which involves no further change in proteinase K resistance, occurs more rapidly in the Met(129) form than the Val(129) form. Although the involvement of such beta-rich oligomers in prion pathogenesis is speculative, the misfolding behavior could, in part, explain the higher susceptibility of individuals that are methionine homozygote to both sporadic and variant Creutzfeldt-Jakob disease.

Long-term survival after blood transfusion: a population based study in the North of England

BACKGROUND

Blood transfusion may transmit infectious diseases with long incubation periods. Estimation of the risks of transmission of such disease requires know-ledge of long-term survival of transfused patients. No such information is available in the UK, where there is particular concern about possible transmission by trans-fusion of variant CJD.

STUDY DESIGN AND METHODS

Information on survival after transfusion and demographics was collected for all patients transfused during June 1994 in a population of 2.9 million served by a single blood center.

RESULTS

A total of 2899 patients were transfused with 10,760 units of RBCs (99% of RBCs issued during the study period). Follow-up to death or 5 years was completed for 98.2 percent, and 46.9 percent of all transfusion recipients were alive at 5 years; 41 percent of transfused RBC units and 36 percent of transfused FFP were given to patients who were alive at 5 years. Median age at transfusion was 67 years (mean, 60.9 years). Shorter patient survival was associated with increasing patient age, increasing numbers of RBC units transfused, trans-fusion of plasma or PLTs, and nonsurgical indications for transfusion.

CONCLUSIONS

Posttransfusion survival is lower than estimated in previous decades in other countries. This is probably due to a relative increase in use of transfusion for older patients and for medical indications. Our figures may be used to predict and stratify the risk of infections, such as variant CJD, amongst different groups of transfusion recipients.

Creutzfeldt-Jakob disease following corneal transplantation

OBJECTIVE

To report a case of possible iatrogenic Creutzfeldt-Jakob many years following penetrating keratoplasty.

DESIGN

Observational case report.

METHODS

We reviewed the patient's chart, available literature on Creutzfeldt-Jakob disease, and current recommendations from the Eye Bank of America Association.

RESULTS

An 80-year-old woman with a history of granular dystrophy underwent penetrating keratoplasty in 1978 (OS) and 1987 (OD) for decreased visual acuity. In early July 2002 the patient developed rapidly progressive dementia. Attempts were made to procure information regarding the corneal donors. No information was available. The patient expired slightly less than 1 month after her onset of symptoms. Review of the EBAA medical standards before October 2002 reveal that donor records were to be kept for a minimum of 10 years.

CONCLUSION

Creutzfeldt-Jakob disease occurred 15 to 24 years after bilateral penetrating keratoplasy, but donor-to-host transmission was uncertain because no information on the corneal donor could be retrieved. Eye-bank records should be kept indefinitely because CJD may occur decades after iatrogenic exposure.

Two Creutzfeldt-Jakob disease agents reproduce prion protein-independent identities in cell cultures

Human Creutzfeldt-Jakob disease (CJD) and similar neurodegenerative diseases such as sheep scrapie are caused by a variety of related infectious agents. They are associated with abnormal host prion protein (PrP), which is assessed by limited proteolysis to yield resistant PrP bands (PrP-res). Although PrP-res has been posited as the infectious agent, purified PrP-res itself is not infectious. To establish the independence of CJD agent characteristics from those of PrP-res, two different mouse-passaged CJD strains were propagated in neuronal cell lines whose PrP-res patterns differ markedly from each other and from those found in infected brain. In mouse brain, the fast CJD strain, FU, elicits many PrP-res deposits, whereas the slow SY strain elicits few. Both strains evoked PrP-res in cultured murine cells, although SY induced PrP-res only transiently. PrP-res patterns in FU- and SY-infected GT1 cells were identical, and were significantly different from those in brain and in N2a cells. Nevertheless, all FU-infected cell lines reproduced their original fast disease in mice, even after extensive subculture, whereas SY-infected cells produced only slow disease. These data indicate PrP-res neither encodes nor alters agent-specific characteristics. PrP-res was also a poor predictor of infectivity because SY cells that had lost PrP-res were approximately 10-fold more infectious than PrP-res-positive cultures. Furthermore, FU titers increased 650-fold, whereas PrP-res remained constant. Passaged FU-infected cells had titers comparable to brain, and >30% of cells displayed abundant cytoplasmic PrP-res aggregates that may trap agent. The continuous substantial replication of CJD in monotypic cells will further the discrimination of agent-specific molecules from pathological host responses to infection.

Creutzfeldt-Jakob disease not related to a common venue--New Jersey, 1995-2004

Beginning in June 2003, the New Jersey Department of Health and Senior Services (NJDHSS) and CDC were notified of a suspected cluster of deaths caused by Creutzfeldt-Jakob disease (CJD) in persons reportedly linked to Garden State Racetrack in Cherry Hill, New Jersey. Concerns were raised that these deaths might have resulted from consumption of meat contaminated with the agent causing bovine spongiform encephalopathy (BSE, commonly called "mad cow disease") served at racetrack restaurants during 1988-1992. Consumption of BSE-contaminated cattle products has been linked to a new variant form of CJD (vCJD) in humans. This report summarizes the results of an investigation that determined the deaths were not linked causally to a common source of infection. The findings underscore the need for physicians to arrange for brain autopsies of all patients with clinically suspected or diagnosed CJD.

[Herbivore or carnivore? History of prions]

Transmissible subacute spongiform encephalopathies have been known for some times in man and in animals, but were considered of minor importance up to the development of the mad cow crisis. Bovine spongiform encephalopathy raises questions about nowadays farming and brings up the issue of cannibalism as a whole and imposed upon an herbivore. Even if the word cannibalism may seem excessive in the case of cattle, it is however true that BSE spreads from cow to cow through their feeding with meat and bone meal contaminated with infected bovine material. More generally this points out the problem of cannibalism among animal species.

Mechanism of intestinal entry of infectious prion protein in the pathogenesis of variant Creutzfeldt-Jakob disease

The pathogenesis of variant Creutzfeldt-Jakob disease (vCJD) is most likely to be dependent on intestinal entry of orally ingested infectious prion proteins, though tonsils or other oral portals of entry are possible. The exact route of entry of infectious prion proteins is uncertain but receptors for prion proteins such as laminin receptor precursor (LRP) may be expressed on intestinal brush border. Cellular prion protein (PrP(c)) is expressed on intestinal enteric nervous system and is separated by a single layer of epithelial cells from ingested infectious prion proteins. Intestinal M cells in the Peyer's patches may also transcytose prion proteins which may be transported to the lymphatic system by migrating dendritic cells underlying the M cells. The relative importance of the several potential portals of intestinal entry of infectious prion proteins is uncertain but may determine susceptibility of the population and also potential preventive strategies.

Mammalian prion biology: one century of evolving concepts

Prions have been responsible for an entire century of tragic episodes. Fifty years ago, kuru decimated the population of Papua New Guinea. Then, iatrogenic transmission of prions caused more than 250 cases of Creutzfeldt-Jakob disease. More recently, transmission of bovine spongiform encephalopathy to humans caused a widespread health scare. On the other hand, the biology of prions represents a fascinating and poorly understood phenomenon, which may account for more than just diseases and may represent a fundamental mechanism of crosstalk between proteins. The two decades since Stanley Prusiner's formulation of the protein-only hypothesis have witnessed spectacular advances, and yet some of the most basic questions in prion science have remained unanswered.

Identification of a second bovine amyloidotic spongiform encephalopathy: molecular similarities with sporadic Creutzfeldt-Jakob disease

Transmissible spongiform encephalopathies (TSEs), or prion diseases, are mammalian neurodegenerative disorders characterized by a posttranslational conversion and brain accumulation of an insoluble, protease-resistant isoform (PrP(Sc)) of the host-encoded cellular prion protein (PrP(C)). Human and animal TSE agents exist as different phenotypes that can be biochemically differentiated on the basis of the molecular mass of the protease-resistant PrP(Sc) fragments and the degree of glycosylation. Epidemiological, molecular, and transmission studies strongly suggest that the single strain of agent responsible for bovine spongiform encephalopathy (BSE) has infected humans, causing variant Creutzfeldt-Jakob disease. The unprecedented biological properties of the BSE agent, which circumvents the so-called "species barrier" between cattle and humans and adapts to different mammalian species, has raised considerable concern for human health. To date, it is unknown whether more than one strain might be responsible for cattle TSE or whether the BSE agent undergoes phenotypic variation after natural transmission. Here we provide evidence of a second cattle TSE. The disorder was pathologically characterized by the presence of PrP-immunopositive amyloid plaques, as opposed to the lack of amyloid deposition in typical BSE cases, and by a different pattern of regional distribution and topology of brain PrP(Sc) accumulation. In addition, Western blot analysis showed a PrP(Sc) type with predominance of the low molecular mass glycoform and a protease-resistant fragment of lower molecular mass than BSE-PrP(Sc). Strikingly, the molecular signature of this previously undescribed bovine PrP(Sc) was similar to that encountered in a distinct subtype of sporadic Creutzfeldt-Jakob disease.

A new kind of prion: a modified protein necessary for its own modification

We recently described an infectious protein (prion) unrelated to amyloid formation, that is an enzyme whose precursor can only be activated by the active form of the enzyme. All previously described infectious proteins are self-propagating amyloid forms of chromosomally encoded proteins. The infectious enzyme, vacuolar protease B (PrB), can activate its own precursor in an indefinitely self-propagating process. Transfer from cell to cell of cytoplasm containing active protease B transmits this non-chromosomal gene. The importance of this system is that many protein-modifying enzymes may act on themselves, and if conditions are right, may become prions as well.