Can C-reactive protein be used as a surrogate marker of IL-6 in a broad array of clinical entities?

Background: C-reactive protein (CRP) is commonly performed, whereas cytokine testing is limited to research. Aims: To determine CRP correlation to cytokines IL-6, IL-1ß and TNF-α. Results: Consecutive samples (n = 307) were collected over 24 h. Ninety-six patients (31%) had acute infections, and 23 patients (7.5%) had autoimmune or inflammatory disease presentations. A strong correlation between CRP and two IL-6 assays (r = 0.74 and r = 0.71; p < 0.001) was present. CRP did not correlate with IL-1ß and TNF-α across the data set. Bacterial infection had a significantly higher CRP and IL-6 (p < 0.001), while only CRP was elevated in inflammatory and autoimmune diseases (p < 0.001). Discussion: CRP may be used as a surrogate marker of IL-6 levels in the routine diagnostic laboratories.

A rapid method for the screening of fatty acids in lipids in plasma or serum without prior extraction.

Serum or plasma are the commonly used blood fractions to determine the relationship between dietary and circulating fatty acids in health and disease. Most methods available for the measurement of fatty acids in serum or plasma (referred to as serum henceforth) require prior extraction with organic solvents. We have determined that it is possible to directly convert the lipids in aqueous biological samples to fatty acid methyl esters (FAME) without prior extraction, providing that the ratio of serum to transmethylation solvent does not exceed 10%. Our in-vial transmethylation system uses 50uL serum pipetted into 2 mL screw top GC vials containing 1 mL of 1% H2SO4 in methanol at 50 °C and subsequent FAME extracted in the same vial into 300uL heptane. The system yields both compositional and quantitative analysis of the fatty acids of serum identical to conventional standard methods. Evaluation of our new serum assay confirms significant correlations between the fatty acid measures and those obtained from conventional standard assay for all fatty acids (r > 0.99, P<0.0001), including the n-6 (r = 0.998, P<0.0001) and n-3 long chain polyunsaturated fatty acids (r = 0.993, P<0.0001). There were high levels of agreement between methods on Bland -Altman analysis, indicating the interchangeability of the methods. These results establish our new method as reliable for the assessment of fatty acid composition of small volumes of serum useful for high throughput situations that limits the volume of organic solvents and technical input.

Prolactin Biology and Laboratory Measurement: An Update on Physiology and Current Analytical Issues.

Prolactin is a 23 kDa single chain protein of 199 amino acids synthesised and released principally by lactotrophs in the anterior pituitary gland. The secretion is mainly under inhibitory control by hypothalamic dopamine and regulated in a negative feedback manner, with prolactin itself providing the afferent signal: short-loop feedback. The main function of prolactin is during pregnancy and lactation in the development of mammary glands, milk synthesis and maintenance of milk secretion. Serum prolactin levels rise rapidly during pregnancy with increase in the size and number of lactotrophs. During lactation suckling induces rapid secretion of prolactin via a neuroendocrine reflex pathway. In the absence of pregnancy, hyperprolactinaemia may present with symptoms of hypogonadotropic hypogonadism including menstrual disturbance and infertility or visual symptoms from a pituitary mass effect by a prolactinoma, the most common pituitary tumour. Hyperprolactinaemia is diagnosed by laboratory measurement of serum prolactin. There is considerable variability in routinely available prolactin immunoassays as a result of differing reactivity towards monomeric prolactin and macroprolactin and lack of commutability of the WHO 3rd International Standard between routine methods. Macroprolactinaemia is a relatively common cause of interference in the prolactin assay that may lead to incorrect diagnosis and unnecessary investigations. Measurement of prolactin post polyethylene glycol precipitation (PEG) when prolactin levels are above the reference interval is routinely used to identify macroprolactin, however harmonisation of PEG precipitation process and reporting may improve clinical care.

Cost effectiveness of high-sensitivity troponin compared to conventional troponin among patients presenting with undifferentiated chest pain: A trial based analysis.

BACKGROUND: Patients with low and intermediate risk chest pain features comprise the greatest proportion presenting to emergency services for evaluation of suspected acute coronary syndromes (ACS). The efficient and timely identification of patients with these features remains a major challenge within clinical practice. Troponin assays are increasingly being used for the determination of risk among patients presenting with chest pain potentially facilitating more appropriate care. To date, no economic evaluation comparing high-sensitivity troponin T (hs-TnT) reporting to standard troponin T (c-TnT) reporting in the routine management of suspected ACS and based on longer-term clinical outcomes has been conducted. METHODS AND RESULTS: An economic evaluation was conducted with 1937 participants randomized to either hs-TnT (n=973) or c-TnT (n=964) with 12month follow-up. The primary outcome measure was the number of cumulative combined outcomes of all-cause mortality and new or recurrent ACS avoided. Mean per participant Australian Medicare costs were higher in the hs-TnT arm compared to the c-TnT arm (by $1285/patient). Mean total adverse clinical outcomes avoided were higher in the hs-TnT arm (by 0.0120/patient) resulting in an incremental cost-effectiveness ratio (ICER) of $108,552/adverse clinical outcome avoided. An ICER of $49,030/adverse clinical outcome avoided was obtained when the analysis was restricted to patients below the threshold of normal Troponin testing (actual c-TnT levels <30ng/L). CONCLUSIONS: hs-TnT reporting leads to fewer adverse clinical events but at a high ICER. For the routine implementation of hs-TnT to be more cost-effective, substantial changes in clinical practice will be required. CLINICAL TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ACTRN12614000189628). https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=365726.

Randomized Comparison of High-Sensitivity Troponin Reporting in Undifferentiated Chest Pain Assessment.

BACKGROUND: High-sensitivity troponin T (hs-TnT) assays promise greater discrimination of evolving myocardial infarction, but the impact of unguided implementation on the effectiveness of care is uncertain. METHODS AND RESULTS: We evaluated the impact of hs-TnT reporting on care and outcome among chest pain patients presenting to 5 emergency departments within a multicenter randomized trial. Patients were allocated to hs-TnT reporting (hs-report) or standard reporting (std-report; Roche Elecys). The primary end point was death and new or recurrent acute coronary syndrome by 12 months. A total of 1937 patients without ST-segment elevation were enrolled between July 2011 and March 2013. The median age was 61 (interquartile range, 48-74) years, and 46.3% were women. During the index hospitalization, 1466 patients (75.7%) had maximal troponin <30 ng/L within 24 hours. Randomization to hs-report format did not alter the admission rate (hs-report: 57.7% versus std-report: 58.0%; P=0.069). There was no difference in angiography (hs-report: 11.9% versus std-report: 10.9%; P=0.479). The hs-reporting did not reduce 12-month death or new/recurrent acute coronary syndrome in the overall population (hs-report: 9.7% versus std-report: 7.2% [hazard ratio, 0.83 (0.57-1.22); P=0.362]). However, among those with troponin levels <30 ng/L, a modest reduction in the primary end point was observed (hs-report: 2.6% versus std-report: 4.4%, [hazard ratio, 0.58; 95% confidence interval, 0.34-0.1.00; P=0.050). CONCLUSIONS: High-sensitivity troponin reporting alone is associated with only modest changes in practice. Clinical effectiveness in the adoption of high-sensitivity troponin may require close coupling with protocols that guide interpretation and care. CLINICAL TRIAL REGISTRATION: URL: http://www.ANZCTR.org.au. Unique identifier: ACTRN12611000879965.

Fluorosis and periostitis deformans as complications of prolonged voriconazole treatment.

We describe a case of development of painful periostitis deformans in a 39-year-old woman who was receiving long-term voriconazole treatment for Aspergillus infection as a complication of orthotopic liver transplant. Measurement of fluoride levels strongly supports fluorosis to be the mechanism of the voriconazole-induced periostitis deformans and supports the concept that such measurements might be of use in predicting this complication of long-term voriconazole treatment.

Consensus Statement for the Management and Communication of High Risk Laboratory Results.

Ineffective test follow-up is a major source of harm for patients around the world. Unreliable communication from medical laboratories (henceforth termed 'laboratories') to clinicians of results that represent critical or significant risk to patients (collectively termed 'high risk results') is a contributing factor to this problem. Throughout Australasia, management practices for such results vary considerably. The recommendations presented in this document are based on best practice derived from the published literature and follow consultation with a wide range of stakeholders. These recommendations were created to harmonise Australasian practices by guiding laboratories in the design and implementation of safe and effective communication procedures for managing high risk results which require timely notification.

High sensitivity-troponin elevation secondary to non-coronary diagnoses and death and recurrent myocardial infarction: An examination against criteria of causality.

BACKGROUND: Myonecrosis provoked by illness unrelated to unstable coronary plaque is common, but uncertainty about a cause-effect relationship with future events challenges the appropriateness of initiating therapies known to be effective in cardiac conditions. We examined the causal relationship between troponin elevation in non-coronary diagnoses and late cardiac events using the Bradford Hills criteria for causality. METHODS AND RESULTS: Patients presenting acutely to South Australian public hospitals receiving at least one troponin between September 2011-September 2012 were included. Diagnoses were classified as coronary, non-coronary cardiac and non-cardiac using the International Classification of Diseases, version 10 Australian Modified, codes. The relationship between peak in-hospital troponin, using a high-sensitivity troponin T assay and adjudicated cardiac and non-cardiac mortality, and subsequent myocardial infarction (MI) was assessed using competing-risk flexible parametric survival models. Troponin results were available for 38,161 patients of whom, 12,645 (33.6%), 3237 (8.5%), and 22,079 (57.9%) patients were discharged with coronary, non-coronary cardiac and non-cardiac diagnoses, respectively. Troponin >14 ng/l was observed in 43.6%. The relationship between troponin and cardiac mortality was stronger among the non-coronary diagnosis group (troponin 1000 ng/l: coronary hazard ratio: 5.1 (95% confidence interval (CI) 4.0-6.6) vs non-coronary hazard ratio: 16.3 (95% CI 12.6-22.4)). The temporal hazard for cardiac death was marked within 30 days in both groups. Among non-coronary diagnoses, the hazard for recurrent MI was higher but did not vary with time. CONCLUSIONS: Consistency with causal criteria between secondary myonecrosis and cardiac events suggest the potential benefit for extending cardiac specific interventions to this population if supported in trials appropriately designed to address competing risks. Troponin elevation precipitated by non-coronary events is common and demonstrates an associations with late mortality that are analogous to spontaneous MI resulting from unstable coronary plaque. These observations help inform the design of randomized clinical trials exploring the benefits and risk of therapies with established benefits in other cardiac conditions. Such studies will need to appropriately account for competing risks in this population of patients.

Study design of embracing high-sensitivity troponin effectively: the value of more information: a randomized comparison.

BACKGROUND: The development of troponin assays with increased diagnostic sensitivity and greater analytic precision has improved the diagnosis of myocardial infarction in high risk patients. However for those patients at intermediate or low risk in whom a small troponin rise is detected, a cascade of clinical decisions and investigations could result; potentially having uncertain impact on recurrent ischemic events and increasing bleeding risk and resource utilization. Clinical equipoise remains as to the clinical utility of high sensitivity troponin. METHODS: We designed a pragmatic randomized clinical trial to evaluate the short and long term clinical impact and resource implications of high sensitivity 5th generation troponin T reporting compared with 4th generation troponin T reporting. Two thousand patients presenting with a suspected acute coronary syndrome were randomized and risk stratified in 5 metropolitan emergency departments in South Australia, Australia. Clinical events occurring after the first 24 h and within 30 days were assessed as the primary endpoint with subsequent events evaluated at 6 and 12 months. CONCLUSION: The true translational benefits of innovations in diagnostic testing need to be evaluated in robust clinical trials as they can be costly to introduce and the adoption process often focuses on sensitivity and specificity at the expense of measuring improvements in clinical outcome. The results of this study will provide valuable information on contemporary patterns of troponin utilization on the heterogeneous population of chest pain patients presenting to emergency departments, while providing important information from the clinical practice setting for health administrators, government and policy makers.

Bone turnover markers.

Bones are constantly remodelled to cope with the body's calcium requirements and to repair microscopic damage. The entire skeleton is replaced every 10 years in adults, and around 10% of the skeleton is involved in bone remodelling at any one time.

Artifactually elevated serum bicarbonate results caused by elevated serum lactate dehydrogenase concentrations.

BACKGROUND: An accurate estimation of serum bicarbonate concentration (HCO3(-)) is essential to the diagnosis and treatment of acid-base disorders and electrolyte disturbances. We noted significant discrepancies between HCO3(-) concentration measured by the Olympus AU2700 analyser and total serum carbon dioxide (TCO2) concentration derived from a Radiometer blood gas analyser on several patient samples. This was reported to the manufacturer which led to a recall of certain reagent lot numbers. We hypothesised the mechanism for this interference to be elevated levels of lactate dehyrogenase (LD). METHODS: We investigated the effect of increasing LD concentration on HCO3(-) with the reagent lot that was recalled and compared this with a subsequent reagent lot that was known to be unaffected on an Olympus AU2700. RESULTS: The experimental data confirmed a positive interference in the Olympus AU2700 HCO3(-) assay using older reagent lot numbers. The false positive HCO3(-) interference was significant (>10% change) when the LD concentration exceeded 845 U/L. CONCLUSIONS: Very high levels of LD concentrations were the cause of interference in the Olympus AU2700 HCO3(-) enzymatic assay. Laboratorians should be aware that very high levels of LD may be a potential interference in some enzymatic HCO3(-) assays.

Calcium supplements lower bone resorption after renal transplant.

AIM: Bone loss in renal transplant (RT) patients is a problem that begins during end-stage kidney disease and persists after transplantation. Suppression of parathyroid hormone (PTH) may decrease bone loss and improve fracture rate. METHODS: A single-group prospective intervention study involving 30 patients was performed at a large RT unit. Investigations included dual-emission X-ray absorptiometry scan, vertebral X-ray, calcium absorption test, 24-h urinary calcium and serum measurements of total and ionized calcium, PTH, C-telopeptide cross-links (CTX), osteocalcin, alkaline phosphatase, 25 hydroxyvitamin D (25[OH]D), and 1,25-dihydroxyvitamin D3. Patients were given 500 mg elemental calcium daily for seven d, and serum measurements were repeated. RESULTS: Two-tailed Wilcoxon rank-sum test showed significant decreases in PTH (p<0.01) and CTX (p<0.01) after calcium load. Dietary calcium, mean calcium absorption, and urinary calcium excretion were below desirable levels. Mean 25 hydroxyvitamin D (25(OH)D) was low, but levels of 1,25-dihydroxyvitamin D3 were normal. Calcium absorption significantly correlated with change in PTH (p<0.001), baseline 25(OH)D (p<0.001), and mycophenolate dose (p=0.024). CONCLUSIONS: Calcium malabsorption is prevalent in RT recipients, contributing to bone destruction and compounded by poor dietary intake and low 25(OH)D. Calcium supplementation appears to help overcome this deficiency and acutely suppress PTH. Calcium may be an effective and inexpensive therapy for bone loss in RT recipients.

The correlation between third-trimester maternal and newborn-serum 25-hydroxy-vitamin D in a selected South Australian group of newborn samples.

BACKGROUND: Although vitamin D insufficiency is prevalent in the community, only a few population-based studies have measured serum 25-hydroxy-vitamin D (25OHD) levels during pregnancy and in newborns. Maternal vitamin D deficiency has been linked to pregnancy complications, as well as hypocalcaemia and rickets in the newborn. Here, the authors report third-trimester maternal and newborn-serum 25OHD concentrations in 101 neonates whose serum samples were sent for testing. METHODS: The newborn 25OHD levels were correlated with the third-trimester maternal serum 25OHD levels using a least-square regression analysis. All samples were measured using an enzyme immunoassay (EIA). Ten randomly selected newborn serum samples were also measured using liquid chromatography/tandem mass spectrometry LC-MSMS, and correlated with the EIA method. RESULTS: Out of 99 mothers of the newborns, only 19, 42 and 68 had their 25OHD level measured in the first, second and third trimester respectively. The mean maternal age was 30 years, while the mean maternal third-trimester 25OHD concentration was 48 nmol/l. Of the newborns, 53% were female, and 85% were term deliveries. The mean newborn-serum 25OHD was 68 nmol/l. Neonatal 25OHD was related to maternal third-trimester levels measured by EIA (r=0.3; newborn 25OHD=0.42(maternal 25OHD)+44.2; p=0.02). EIA and LC-MSMS concentrations for newborns correlated significantly over a range between 20 and 103 nmol/l by EIA (r=0.9; EIA=1.04(LCMSMS)+10.1; p<0.00 (slope); p=0.18 (intercept)). The mean 25OHD concentration in women who suffered pre-eclampsia and premature rupture of membranes were 45 and 39 nmol/l respectively. CONCLUSIONS: Newborn-serum 25OHD concentrations depend on the maternal circulating plasma 25OHD level at least during the third trimester. Neonatal 25OHD levels obtained by EIA correlated well with LC-MSMS. Although the EIA values for neonates were greater than LC-MSMS values, this difference was not statistically significant.

Physical and catalytic properties of a peroxidase derived from cytochrome c.

Except for its redox properties, cytochrome c is an inert protein. However, dissociation of the bond between methionine-80 and the heme iron converts the cytochrome into a peroxidase. Dissociation is accomplished by subjecting the cytochrome to various conditions, including proteolysis and hydrogen peroxide (H(2)O(2))-mediated oxidation. In affected cells of various neurological diseases, including Parkinson's disease, cytochrome c is released from the mitochondrial membrane and enters the cytosol. In the cytosol cytochrome c is exposed to cellular proteases and to H(2)O(2) produced by dysfunctional mitochondria and activated microglial cells. These could promote the formation of the peroxidase form of cytochrome c. In this study we investigated the catalytic and cytolytic properties of the peroxidase form of cytochrome c. These properties are qualitatively similar to those of other heme-containing peroxidases. Dopamine as well as sulfhydryl group-containing metabolites, including reduced glutathione and coenzyme A, are readily oxidized in the presence of H(2)O(2). This peroxidase also has cytolytic properties similar to myeloperoxidase, lactoperoxidase, and horseradish peroxidase. Cytolysis is inhibited by various reducing agents, including dopamine. Our data show that the peroxidase form of cytochrome c has catalytic and cytolytic properties that could account for at least some of the damage that leads to neuronal death in the parkinsonian brain.

Liver function tests.

This article forms part of our 'Tests and results' series for 2011 which aims to provide information about common tests that general practitioners order regularly. It considers areas such as indications, what to tell the patient, what the test can and cannot tell you, and interpretation of results. Liver function tests (LFTs) are a panel of blood markers (Table 1) used to assess and monitor several diseases. However, they are not all true tests of liver function and abnormalities may not reflect liver disease.

Hyperparathyroidism and vitamin D deficiency predispose to bone loss in renal transplant recipients.

BACKGROUND: Bone disease is common postrenal transplantation resulting in increased fracture rates and morbidity. The cause is multifactorial including hyperparathyroidism, corticosteroids, and possibly calcium and vitamin D deficiencies. The aim of this study was to identify modifiable factors contributing to bone disease in long-term renal transplant (RT) recipients. METHODS: Ninety-seven RT recipients were prospectively recruited over a 6-month period from a single center. Bone-related parameters were collected including bone mineral density at lumbar spine and total hip sites, serum and urinary markers of bone-turnover and calcium metabolism, and intact parathyroid hormone levels. RESULTS: The mean time posttransplant of RT recipients was 9.5 years and mean estimated glomerular filtration rate was 70.3 mL/min. Up to 50% of recipients had biochemical evidence of calcium and vitamin D deficiencies. In the multiple regression models, elevated intact parathyroid hormone levels and calcium deficiency, which are affected by estimated glomerular filtration rate and vitamin D levels, are significantly associated with reduction in bone mineral density measurements. CONCLUSIONS: Hyperparathyroidism and vitamin D deficiency are common and are likely to contribute to bone loss postrenal transplantation. Measures aim to correct these problems pre- and posttransplant may improve bone health in RT recipients.

Calcium malabsorption does not cause secondary hyperparathyroidism.

We challenge the widespread assumption that malabsorption of calcium per se causes secondary hyperparathyroidism. Serum parathyroid hormone (PTH) does not rise at the menopause despite the fall in calcium absorption, nor is it raised in osteoporotic women with vertebral fractures despite their low calcium absorption. The age-related rise in serum PTH can be accounted for by the age-related fall in serum 25(OH)D and/or decline in renal function with consequent loss of the calcemic action of vitamin D on bone. The reference interval for serum PTH is established in the fasting state when it is at the top of its diurnal cycle and is maintaining serum ionized calcium at the expense of bone to meet the calcium being lost through skin, bowel, and kidneys. There is no evidence that the fasting PTH is influenced by the previous day's intake or absorption of calcium, although it can be lowered by a large evening calcium supplement. Malabsorption of calcium-like dietary calcium deficiency-is a risk factor for osteoporosis because it reduces or prevents the normal food-related daytime fall in PTH and bone resorption, not because it causes secondary hyperparathyroidism.

A family of splice variants of CstF-64 expressed in vertebrate nervous systems.

BACKGROUND: Alternative splicing and polyadenylation are important mechanisms for creating the proteomic diversity necessary for the nervous system to fulfill its specialized functions. The contribution of alternative splicing to proteomic diversity in the nervous system has been well documented, whereas the role of alternative polyadenylation in this process is less well understood. Since the CstF-64 polyadenylation protein is known to be an important regulator of tissue-specific polyadenylation, we examined its expression in brain and other organs. RESULTS: We discovered several closely related splice variants of CstF-64 - collectively called betaCstF-64 - that could potentially contribute to proteomic diversity in the nervous system. The betaCstF-64 splice variants are found predominantly in the brains of several vertebrate species including mice and humans. The major betaCstF-64 variant mRNA is generated by inclusion of two alternate exons (that we call exons 8.1 and 8.2) found between exons 8 and 9 of the CstF-64 gene, and contains an additional 147 nucleotides, encoding 49 additional amino acids. Some variants of betaCstF-64 contain only the first alternate exon (exon 8.1) while other variants contain both alternate exons (8.1 and 8.2). In mice, the predominant form of betaCstF-64 also contains a deletion of 78 nucleotides from exon 9, although that variant is not seen in any other species examined, including rats. Immunoblot and 2D-PAGE analyses of mouse nuclear extracts indicate that a protein corresponding to betaCstF-64 is expressed in brain at approximately equal levels to CstF-64. Since betaCstF-64 splice variant family members were found in the brains of all vertebrate species examined (including turtles and fish), this suggests that betaCstF-64 has an evolutionarily conserved function in these animals. betaCstF-64 was present in both pre- and post-natal mice and in different regions of the nervous system, suggesting an important role for betaCstF-64 in neural gene expression throughout development. Finally, experiments in representative cell lines suggest that betaCstF-64 is expressed in neurons but not glia. CONCLUSION: This is the first report of a family of splice variants encoding a key polyadenylation protein that is expressed in a nervous system-specific manner. We propose that betaCstF-64 contributes to proteomic diversity by regulating alternative polyadenylation of neural mRNAs.

Neurodegeneration and peroxidases.

Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS) are neurodegenerative diseases that affect different parts of the central nervous system. However, a review of the literature indicates that certain biochemical reactions involved in neurodegeneration in these three diseases are quite similar and could be partly identical. This article critically examines the similarities and, based on data from our own and other laboratories, proposes a novel explanation for neurodegeneration in these three diseases. We identified about 20 commonalities that exist in the neurodegenerative process of each disease. We hypothesize that there are two enzyme-catalyzed pathways that operate in affected neurons: an oxidative pathway leading to destruction of various neuronal proteins and lipids, and an apoptotic pathway which the body normally uses to remove unwanted and dysfunctional cells. Data from many laboratories indicate that oxidative reactions are primarily responsible for neurodegeneration, whereas apoptosis may well be a secondary response to the presence of neurons that have already been severely damaged by oxidative reactions. Attempts to inhibit apoptosis for the purpose of attenuating progression of these diseases may therefore be only of marginal benefit. Specific oxidative reactions within affected neurons led us to propose that one or more heme peroxidases may be the catalyst(s) involved in oxidation of proteins and lipids. Support for this proposal is provided by the recent finding that amyloi-beta peptide may act as a peroxidase in AD. Possible participation of the peroxidase activity of cytochrome c, herein designated as cytochrome c(px) to distinguish it from yeast cytochrome c peroxidase, is discussed. Of special interest is our recent finding that many compounds that cause attenuation of neurodegeneration are inhibitors of the peroxidase activity of cytochrome c. Several inhibitors were subsequently identified as suicide substrates. Such inhibitors could be ideally suited for targeted clinical approaches aimed at arresting progression of neurodegeneration. Finally, it is possible that immobilized yet still active peroxidase(s) may be present in protein aggregates in AD, PD, and ALS. This activity could be the catalyst for the slow, self-perpetuating and irreversible degeneration of affected neurons that occurs over long periods of time in these neurodegenerative diseases.