A more sensitive radioimmunoassay for neuron-specific enolase suitable for cerebrospinal fluid determinations

Dual-mode biosensor using Tb-Cu MOF@Au nanoenzyme to effectively quench the photocurrent of Bi2O3/Bi2S3/AgBiS2 heterojunction and emit fluorescence for neuron-specific enolases detection

A novel dual-mode biosensor was constructed for the ultrasensitive detection of neuron-specific enolase (NSE), utilizing Tb-Cu MOF@Au nanozyme as the signal label to effectively quench the photoelectrochemical (PEC) signals of Bi2O3/Bi2S3/AgBiS2 composites and initiate fluorescent (FL) signals. First, Bi2O3/Bi2S3/AgBiS2 heterojunction with excellent photoelectric activity was selected as the substrate material to provide a stable photocurrent. The well-matched energy levels significantly enhanced the separation and transfer of photogenerated carriers. Second, a strategy of consuming ascorbic acid (AA) by Tb-Cu MOF@Au nanozyme was introduced to improve the sensitivity of the PEC/FL biosensor. Tb-Cu MOF@Au not only could catalyze the oxidation of AA, but the steric effect further reduced the contact of AA with the substrate. More importantly, in the presence of H2O2, a significant fluorescence was produced from Tb3+ sensitized by the oxidation products of AA. Based on the above strategies, a highly stable and sensitive dual-mode biosensor was proposed for accurate NSE determination. Third, the developed dual-mode biosensor demonstrated excellent performance in detecting NSE. In this study, the PEC method demonstrated a wide detection range from 0.00005 to 200 ng/mL with a low detection limit of 20 fg/mL. The FL method exhibited a linear range from 0.001 to 200 ng/mL with a detection limit of 0.65 pg/mL. The designed biosensor showed potential practical implications in the accurate detection of disease markers.

Detection of NSE by a photoelectrochemical self-powered immunosensor integrating RGO photocathode and WO3/Mn:CdS nanomaterial photoanode

Generally, the photoanodic photoelectrochemical (PEC) immunoassay method has an outstanding photocurrent and low detection limit, but its poor anti-interference ability in the detection of real samples restricts its performance. The photocathode immunoassay method has an excellent ability to see interference in actual sample detection, but it has its own defect in that the photocurrent is not obvious. Here, a promising new cathodic PEC immunosensing platform is reported, which integrates a photocathode and photoanode. The photoanode and photocathode are WO₃/Mn:CdS composite modified and reduced graphene oxide (RGO) modified indium tin oxide (ITO) electrodes, respectively. In addition to an excellent PEC response, the immunosensor constructed by the integrating the photoanode and photocathode also has good anti-interference ability in actual sample analysis. The constructed immunosensor achieves accurate detection of NSE with a range from 5.0 pg/mL to 20 ng/mL, and the limit of detection (LOD) is 1.2 pg/mL. The proposed immunoassay method has good stability, selectivity and reproducibility. Moreover, it introduces new ideas for the construction of PEC immunosensors.

Multifunctional neuron-specific enolase: its role in lung diseases

Neuron-specific enolase (NSE), also known as gamma (γ) enolase or enolase-2 (Eno2), is a form of glycolytic enolase isozyme and is considered a multifunctional protein. NSE is mainly expressed in the cytoplasm of neurons and neuroendocrine cells, especially in those of the amine precursor uptake and decarboxylation (APUD) lineage such as pituitary, thyroid, pancreas, intestine and lung. In addition to its well-established glycolysis function in the cytoplasm, changes in cell localization and differential expression of NSE are also associated with several pathologies such as infection, inflammation, autoimmune diseases and cancer. This article mainly discusses the role and diagnostic potential of NSE in some lung diseases.

Altered Expression of Glucocorticoid Receptor and Neuron-Specific Enolase mRNA in Peripheral Blood in First-Episode Schizophrenia and Chronic Schizophrenia

INTRODUCTION

It is well-known that altered hypothalamus-pituitary-adrenal (HPA) axis process has an important role in the neurodegenerative process in schizophrenia (SZ). However, this neurodegenerative mechanism has not been clarified in SZ. Therefore, the main purpose of this study was to determine HPA axis damage in the first-episode, unmedicated schizophrenia (FES) patients and chronic schizophrenia (CSZ) patients in comparison with healthy controls (HC) by means of quantitative analysis of the peripheral blood mRNA expression of glucocorticoid receptor (GR), GR transcripts containing exons 1B (GR-1B), and neuron specific enolase (NSE) genes and serum cortisol and NSE, a specific serum marker for neuronal damage.

METHODS

In the present study, 43 FES patients, 39 CSZ, and 47 HC were included. The peripheral blood mRNA expressions for GR, GR-1B, and NSE genes were determined by real-time quantitative polymerase chain reaction (RT-qPCR). Serum cortisol and NSE were analyzed by electrochemiluminescence immunoassay technique.

RESULTS

Levels of GR mRNA were significantly lower in FES and CSZ than that in HC. The expression of GR-1B mRNA was significantly decreased in CSZ when compared with that in FES. Levels of NSE mRNA were significantly lower in CSZ than that in FES patients or HC patients. CSZ patients showed significantly lower cortisol concentrations than FES and HC patients. FES patients showed significantly higher NSE concentrations than CSZ and HC.

CONCLUSION

Our findings support that there is disrupted HPA axis system in the SZ and suggest that CSZ patients suffer a greater HPA axis damage than FES patients. Our research implicated underlying GR mRNA dysregulation in SZ and the potential importance of the functional GR-1B transcription in CSZ.

Neuron-Specific Enolase as a Biomarker: Biochemical and Clinical Aspects

Neuron-specific enolase (NSE) is known to be a cell specific isoenzyme of the glycolytic enzyme enolase. In vertebrate organisms three isozymes of enolase, expressed by different genes, are present: enolase α is ubiquitous; enolase β is muscle-specific and enolase γ is neuron-specific. The expression of NSE, which occurs as γγ- and αγ-dimer, is a late event in neural differentiation, thus making it a useful index of neural maturation.NSE is a highly specific marker for neurons and peripheral neuroendocrine cells. As a result of the findings of NSE in specific tissues under normal conditions, increased body fluids levels of NSE may occur with malignant proliferation and thus can be of value in diagnosis, staging and treatment of related neuroendocrine tumours (NETs).NSE is currently the most reliable tumour marker in diagnosis, prognosis and follow-up of small cell lung cancer (SCLC), even though increased levels of NSE have been reported also in non-small cell lung cancer (NSCLC). The level of NSE correlates with tumour burden, number of metastatic sites and response to treatment.NSE can be also useful at diagnosis of NETs and gastroenteropancreatic (GEP)-NETs.Raised serum levels of NSE have been found in all stages of neuroblastoma, although the incidence of increased concentration is greater in widespread and metastatic disease. Moreover, NSE determination in cord blood offers an early postnatal possibility of confirming the diagnosis of neuroblastoma in newborns.NSE has been demonstrated to provide quantitative measures of brain damage and/or to improve the diagnosis and the outcome evaluation in ischaemic stroke, intracerebral hemorrhage, seizures, comatose patients after cardiopulmonary resuscitation for cardiac arrest and traumatic brain injury.Increased NSE serum levels have also been found associated with melanoma, seminoma, renal cell carcinoma, Merkel cell tumour, carcinoid tumours, dysgerminomas and immature teratomas, malignant phaechromocytoma, Guillain-Barré syndrome and Creutzfeldt-Jakob disease.

Increased lipid peroxidation and neuron specific enolase in treatment refractory schizophrenics

It is well-known that increased lipid peroxidation and failure of antioxidant mechanisms leads to neuronal damage in schizophrenic patients. However, this neurodegenerative mechanism has not been studied in treatment refractory schizophrenics (TRS). Therefore, the main purpose of this study was to determine neuronal damage in TRS in comparison to non-refractory schizophrenics (NRS) by means of quantitative analysis of lipid peroxidation and neuron specific enolase (NSE) related to the psychopathology severity. Two groups of paranoid schizophrenics, TRS and NRS, and a group of healthy controls (CO) were assembled (n=13). Lipid peroxidation was analyzed through spectrophotometry for quantification of malonaldehyde (MDA) and 4-hydroxynonenal (4-HNE) serum concentrations. As well, serum NSE was quantified by radioimmunoassay (ELSA). Psychopathology was evaluated using the brief psychiatric rating scale (BPRS) and the positive and negative symptoms scale (PANSS). TRS showed significant higher concentrations of lipoperoxides by-products and NSE, than NRS and CO. Clinical scores also revealed a more severe pathology in TRS, than in NRS. Raised lipoperoxidation correlated with higher delusions and emotional withdrawal symptoms, and increased NSE correlated with a lower flow of the conversation and lack of spontaneity. All these results together suggest that TRS patients suffer a greater lipid peroxidation and neuronal damage than NRS, apparently related to worsening of some of the psychiatric symptoms.

Molecular Mechanisms of Neurologic Injury Following Cardiopulmonary Bypass

Neurologic injury is a potentially devastating consequence of heart surgery. Between 1% and 5% of patients undergoing cardiopulmonary bypass have postoperative strokes and 30% to 80% of patients demonstrate some neurologic dysfunction postoperatively. This review focuses on anatomic, molecular and clinical markers of neurologic injury following cardiopulmonary bypass. Attention is directed to the molecular mechanisms underlying neurologic injury and clinical biochemical markers of injury during heart surgery. Novel strategies to modulate injury are also discussed.

Capillary electrophoretic analyses of beta-trace protein and other low molecular weight proteins in cerebrospinal fluid from patients with central nervous system diseases

Ordinary capillary-zone electrophoresis (CZE), as well as CZE in a sodium dodecylsulfate-containing polymer solution (SDS-CZE) and capillary isoelectrofocusing (CIEF), was applied to the analysis of low molecular weight proteins in cerebrospinal fluid (CSF) from patients with various neuropsychiatric disorders. Under the CZE conditions employed, a peaks of beta-trace protein (beta TP), which is the most abundant low MW protein in CSF, was clearly detected on the electropherograms of all the samples examined, and the CSF beta TP level could be tentatively determined using allylamine added at a constant concentration as the internal standard. The results revealed that beta TP in CSF was non-specifically increased in organic disease in the central nervous system (CNS), especially in ones giving severe physical damage to the brain tissues. On the other hand, SDS-CZE allowed us to determine simultaneously the CSF minor low MW proteins other than beta TP, such as beta 2-microglobulin, gamma-trace protein, myelin basic protein, etc., while the CIEF electropherograms suggested that beta TP were separated into several fractions with the different PI values. These capillary electrophoresis systems seem to be powerful as aids in the biochemical examinations of beta TP and other low molecular weight proteins in CSF from patients with CNS diseases.

Neuron specific enolase in cerebrospinal fluid: a biochemical marker for neuronal degeneration in dementia disorders?

Alzheimer's disease (AD) is the most common disease causing dementia. Today the clinical diagnosis of AD is made by way of exclusion, and no biochemical markers are available to assist the clinical diagnosis. We examined the potential of neuron-specific enolase (NSE) in cerebrospinal fluid (CSF) as a diagnostic marker for AD. NSE was determined with a monoclonal antibody two-site immunoradiometric assay (IRMA) in serum (S) and cerebrospinal fluid (CSF) samples from 45 patients with "probable Alzheimer's disease (AD)", 19 patients with vascular dementia (VAD) and 33 age-matched healthy individuals. There was no significant correlation between S-NSE and CSF-NSE, or between CSF/S albumin ratio and CSF-NSE, findings suggesting that the major portion of CSF-NSE is intrathecally produced and that analysis of CSF-NSE alone (without accompanying analysis of serum) is sufficient. CSF-NSE was significantly higher in the AD group (4.7 +/- 2.7 ng/mL; p < 0.0001) and in VAD group (4.5 +/- 2.5 ng/mL; p < 0.001) as compared with the control group (2.2 +/- 1.0 ng/mL), while it did not differ significantly between the AD and the VAD group. These findings suggest that CSF-NSE have a potential as a non-disease specific marker for the neuronal degeneration in dementia disorders.

Cerebrospinal fluid and serum levels of neuron-specific enolase in patients with schizophrenia

Some patients with schizophrenia appear to have brain abnormalities, including enlarged third and lateral ventricles and reduced volumes of temporal lobe structures. These abnormalities could be attributed to a developmental abnormality or a neurodegenerative process. Neuron-specific enolase (NSE), a protein that is found primarily in neurons and neuroendocrine cells, has been used as an index of neuronal damage or degeneration. Levels of NSE in cerebrospinal fluid (CSF) and serum from 50 patients with acute and chronic schizophrenia were compared with those in normal and neurological control subjects. A double-antibody, solid phase iodinated radioimmunoassay was used to determine NSE levels. There was no evidence of elevated levels in patients with schizophrenia, whereas control subjects with neurological illnesses had increased levels of NSE in CSF. Because NSE is rapidly cleared from CSF, however, elevated levels could have been missed. Unmedicated patients tended to have lower levels than medicated patients.

Electrophoretic assessment of aqueous and serum neurone-specific enolase in retinoblastoma and ocular malignant melanoma

The isoenzyme pattern of enolase was examined in the aqueous humour and serum of patients with retinoblastoma (10 aqueous, 8 sera), malignant melanoma (4 aqueous, 25 sera), and normal subjects undergoing cataract surgery (25 aqueous, 30 sera). The assay we used allowed assessment of all three major isoenzymes, including the gamma gamma isoenzyme (neurone-specific enolase). No enolase was detectable in normal aqueous; alpha alpha isoenzyme was present in the aqueous of one patient with malignant melanoma, while aqueous from all patients with retinoblastoma contained both alpha alpha and gamma gamma. Normal serum contained only an alpha alpha band, while serum from patients with retinoblastoma contained alpha alpha, alpha gamma, and gamma gamma bands (7 sera, 87.5%), or alpha alpha only (1 patient, 12.5%). All sera from patients with malignant melanoma contained the alpha alpha band, with low levels of gamma gamma in 16 (60%). In a single patient with Coats's disease alpha alpha was present in the serum, but no enolase was detected in aqueous. Increased amounts of gamma-containing isoenzymes of enolase are found in both serum and aqueous from patients with retinoblastoma. In malignant melanoma there is often an increase in serum gamma gamma enolase. The assessment of aqueous and serum enolase patterns may be of value in the diagnosis of retinoblastoma and malignant melanoma.

Detection of neuron specific enolase concentrations in cerebrospinal fluid from patients with neurological disorders by means of a sensitive enzyme immunoassay

An enzyme linked immunosorbent assay (ELISA) for the detection of neuron specific enolase (NSE) in cerebrospinal fluid (CSF) was developed. The sensitivity of the ELISA was less than 1 microgram/ml. This sensitivity is comparable with radioimmunoassays which have the disadvantage that radiolabelled products are used. The developed assay was used to measure cerebrospinal fluid neuron specific enolase (CSF-NSE) levels in 1178 patients with neurological disorders to establish its potential usefulness and clinical application. CSF-NSE levels in this group of patients were independent of sex and no correlation with age was found. CSF-NSE was significantly increased in Creutzfeldt-Jacob disease, meningeal hemorrhage, thrombosis, Guillain-Barré syndrome and in schizophrenia.

Capillary-isotachophoretic determination of glutamine in cerebrospinal fluid of various neurological disorders

A rapid and microscale technique to detect and determine L-glutamine (Gln), which is the most abundant free amino acid in human cerebrospinal fluid (Sf), was established on the basis of capillary-isotachophoresis. This system was applied to the measurement of Sf Gln concentration in various neurological disorders. The results showed that Sf Gln was increased under some pathological conditions in the central nervous system, especially those accompanying pleocytosis in Sf.

Clinical biochemistry of neuron specific enolase

The soluble brain protein 14-3-2 first described by Moore and McGregor in 1965 is now known to be a cell specific isoenzyme of the glycolytic enzyme enolase (EC 4.2.1.11), designated neuron specific enolase (NSE). It is not only a marker for all types of neurons, but also for all neuroendocrine or paraneuronal cells. The appearance of NSE is a late event in neural differentiation, thus making NSE a useful index of neural maturation. The demonstration that tumors of the nervous system and of neuroendocrine origin contain NSE has promoted the study of NSE as a possible tumor marker. Immunocytochemistry has been used to identify NSE in cytologic preparations from several types of tumors, offering useful indications for differential diagnosis. NSE levels in serum from tumor patients are not useful in the diagnosis of early stage disease. However, serum NSE levels have been shown to be helpful in the identification of advanced small cell lung cancer, neuroblastoma and several other neoplasms. The main use of serum NSE is the monitoring of chemotherapy and the detection of a relapse in these cases.

Neuron-specific enolase and its mRNA are highly expressed in large congenital nevi: a study using immunocytochemistry, biochemical assay, and in situ hybridization

The malignant transformation of congenital nevocellular nevi, both large and small, is controversial and presents problems in management. The size of the lesion is taken to indicate potential malignant transformation, but this is an arbitrary scale. A more reliable biological indicator is needed to help predict the lesions at risk. Following the localization of neuron-specific enolase to most cells of the diffuse neuroendocrine system and their neoplasms (including benign and malignant melanocytic lesions), it has been suggested that its level is related to tumor activity. In a prospective trial, the presence of neuron-specific enolase immunoreactivity, its concentration, and gene expression in nevus cells were studied in 31 congenital melanocytic nevi of various sizes (1.5 cm to bathing trunk) using immunocytochemistry, biochemical assay, and in situ hybridization. Twenty-five of the 31 congenital nevi were immunoreeactive to neuron-specific enolase antiserum, with stronger immunostaining in the larger lesions. There is an apparent linear relationship between the size of the nevi and the level of neuron-specific enolase (expressed as nanograms per milligram protein). Neuron-specific enolase mRNA was highly expressed in most of the large congenital nevi (greater than 15 cm in diameter), as revealed by autoradiography following in situ hybridization. Our results show that neuron-specific enolase and its mRNA are expressed to a greater extent in large congenital nevi compared with the smaller lesions. This might prove to be a useful indicator of those lesions at risk of malignant transformation.

An immunobioluminescence assay for gamma-gamma enolase activity in human serum and cerebrospinal fluid

A solid phase immunobioluminescence assay for the measurement of gamma-gamma enolase activity in human serum and cerebrospinal fluid is described. The assay combines the specificity of the antiserum with the specificity of measuring enolase activity, thus making the assay highly specific for gamma-gamma enolase. The sensitivity of the method allows determinations in unconcentrated cerebrospinal fluid samples. The new immunobioluminescence assay has been compared with a radioimmunoassay method. The correlation is good both for serum and CSF samples. However, different correlation lines are found for serum and CSF.

S-100 protein and neuron-specific enolase in cerebrospinal fluid and serum: markers of cell damage in human central nervous system

The development of a radioimmunoassay for S-100 protein is described. This method was used in combination with a recently developed radioimmunoassay for neuron-specific enolase in cerebrospinal fluid and serum from 47 patients with cerebral infarction, transient ischemic attack, intracerebral hemorrhage, subarachnoid hemorrhage, and head injury. In cerebrospinal fluid, increased concentrations of both S-100 and neuron-specific enolase were found after large infarcts, whereas after small infarcts and transient ischemic attacks, only neuron-specific enolase increased. The increased concentrations of S-100 and/or neuron-specific enolase were noted 18 hours to 4 days after cerebral infarction and transient ischemic attacks. Cerebrospinal fluid concentrations of these proteins also reflected the severity of the disease in patients with intracerebral hematoma, subarachnoid hemorrhage, or head injury. Temporal changes in serum S-100 and neuron-specific enolase concentrations reflected the clinical course in 4 patients. In stroke patients, the S-100 and neuron-specific enolase concentrations may reflect the extent of brain damage and could be useful in selecting patients with major stroke for more aggressive treatment during the acute phase.

Serial determination of serum neuron-specific enolase in patients with neuroblastoma and other pediatric tumors

The importance of determination of serum neuron-specific enolase (NSE) in patients with neuroblastoma has been emphasized by several authors. However, the specificity and sensitivity of NSE have not yet been well studied in tumors of infancy and childhood, nor is the role of serial determination of NSE in monitoring these patients fully understood. Concentrations of serum NSE were determined by a newly developed radioimmunoassay technique in 241 samples from 111 patients. NSE was also assayed in sera of nude mice bearing human pediatric tumors (16 samples), as well as in 30 tumor specimens. Eighty-two serum samples from 19 patients with neuroblastoma all showed NSE values (mean 120.2 ng/mL, range 16.2 to 722.0 ng/mL) elevated beyond the upper border of the normal range (14.6 ng/mL), even though four of the 19 patients had normal urinary excretion of 3-methoxy-4-hydroxymandelic acid (VMA) and 3-methoxy-4-hydroxy-phenylacetic acid (HVA). Twelve of these patients were monitored with serial NSE determinations, and their serum NSE were found to correlate well with the tumor burden, but were transiently modified by chemotherapeutically induced cell death. All 68 samples from nine patients, free of neuroblastoma at assessment, showed NSE values within the normal range. Thirteen of 25 patients with tumors other than neuroblastoma, however, showed serum NSE values mildly elevated beyond the upper border of the normal range (mean of the 25 patients 36.7 ng/mL, range 5.0 to 234.0 ng/mL). Results from our nude mouse study and from NSE analysis of the tumor extracts paralleled the clinical results.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of AIDS virus in macrophages in brain tissue from AIDS patients with encephalopathy

One of the common neurological complications in patients with the acquired immune deficiency syndrome (AIDS) is a subacute encephalopathy with progressive dementia. By using the techniques of cocultivation for virus isolation, in situ hybridization, immunocytochemistry, and transmission electron microscopy, the identity of an important cell type that supports replication of the AIDS retrovirus in brain tissue was determined in two affected individuals. These cells were mononucleated and multinucleated macrophages that actively synthesized viral RNA and produced progeny virions in the brains of the patients. Infected brain macrophages may serve as a reservoir for virus and as a vehicle for viral dissemination in the infected host.

Varicella-zoster virus infection of human sensory neurons

Primary varicella-zoster virus (VZV) infection of humans may result in latent infection of sensory neurons in the peripheral nervous system. To examine the interaction of VZV with the sensory neuron we infected immunochemically defined human neurons with cell-associated VZV. Utilizing double-label immunofluorescence technology, a VZV-specific glycoprotein and a nonglycosylated phosphoprotein were detected in human fetus dorsal root ganglion (DRG) neurons, as defined by the presence of the neuron-specific enolase isoenzyme and the A2B5 ganglioside antigen, respectively. In addition to VZV antigen expression, progressive virus-induced cytopathic damage (neuronal enlargement and nuclear granulation of a fraction of the neuron population) was evident. As determined by transmission electron microscopy, VZV-infected human fetus DRG neurons contained empty and complete nucleocapsids with numerous pleomorphic virus particles in the cytoplasm, often in association with vacuoles. Although virus-specific antigen expression, particle synthesis, and cytopathic effects were observed in the human neuron population, neurons were less susceptible to VZV-induced cytopathic damage than supporting nonneuronal cells, suggesting neuronal modulation of VZV infection in vitro. This system provides the first model to examine the neuron- and virus-specific gene(s) and gene product(s) pertinent to the interaction of VZV with the human neuron.

Characteristics of human medulloblastoma cell line TE-671 under different growth conditions in vitro: a morphological and immunohistochemical study

The human medulloblastoma cell line, TE-671, was studied in vitro both in monolayer culture and in a three-dimensional culture system using gelfoam as the supporting matrix. Flow cytometry studies of cells grown in monolayer culture revealed a unimodal, tetraploid DNA content. Most cells in both in vitro systems contained neuron-specific enolase (NSE), actin, and tubulin, while only occasional cells or cell clusters contained the 68,000 molecular weight subunit of neurofilaments (NF mol. wt 68,000) or microtubule-associated protein 2 (MAP-2). In monolayer culture, long cellular processes containing NSE, NF mol. wt 68,000 and MAP-2, which were present at 2 days, were nearly absent by 7 days. All antigens were present at 4 days in the organ culture system; by 72 days, cells still stained positively for NF mol. wt 68 000 and MAP-2, but staining for NSE, actin, and beta-tubulin was diminished as compared to 4 days. Retinoic acid (RA) in the 13-cis isomer form at 10(-6) M was applied to monolayer cultures at day 1 for 6 days and to gelfoam cultures at day 1 for 28 days. RA did not significantly alter cell proliferation up to 7 days in vitro and did not appreciably affect cellular expression of NSE, NF mol. wt 68 000, MAP-2, beta-tubulin, or actin in either system. By electron microscopy, most cells grown under different culture conditions with or without RA treatment appeared to be undifferentiated and polygonal, with occasional cytoplasmic annulate lamellae. The immunohistochemical and ultrastructural features reported indicate that the TE-671 medulloblastoma line is composed primarily of primitive neuroepithelial cells with a limited potential for neuronal differentiation. This differentiation was not promoted by RA or by an in vitro system known to favour differentiation in a number of human and animal nervous system tumours. The findings suggest that the cells of the TE-671 line lack either receptors for retinoic acid or the capacity to respond to bound retinoic acid.

Serum neuron-specific enolase in children with neuroblastoma. Relationship to stage and disease course

Serum neuron-specific enolase (NSE) was measured in 61 children at diagnosis with all stages of neuroblastoma. The median serum values for Stages I, II, III, IV, and IV-S were 13, 23, 40, 214, and 40 ng/ml, respectively. Mean serum levels were different between groups I versus IV, (P = 0.0004) II versus IV (P = 0.0001) and IV-S versus IV (P = 0.004). The prognostic value of serum NSE for disease-free survival was determined in 54 patients at risk for relapse 2 or more years after diagnosis. The disease-free survival rate of all patients with levels of less than 100 ng/ml was 27/34 (79%), whereas it was 2/20 (10%) for those with higher levels. In 28 patients with lower stage disease and a good prognosis (Stages I, II, and IV-S) NSE levels were not predictive of relapse. Only 1 of these 28 patients had a raised level (greater than 100 ng/ml) and survived without relapse, whereas 4 patients who relapsed had serum NSE less than 100 ng/ml at diagnosis. In patients with Stages III and IV disease, a raised serum NSE level was associated with poor outcome: only 1/19 (5%) survived with NSE levels greater than 100 ng/ml, whereas survival was 5/8 (63%) with values below 100 ng/ml. Serial samples were analyzed on 17 patients; all 8 patients with initial NSE levels greater than 100 ng/ml achieved near normal levels during remission (median, 21 ng/ml). However, in only 4/10 patients studied at time of relapse, did the levels rise coincident with relapse. The sera of 47 patients with other forms of cancer and 19 siblings of cancer patients were at or near the normal limits (0-15 ng/ml), with three exceptions: acute lymphoblastic leukemia (286 ng/ml), hepatoblastoma (176 ng/ml), and primitive neuroectodermal tumor (105 ng/ml). Serum NSE is a useful marker for patients with advanced neuroblastoma in whom elevated levels were associated with a poor outcome; the raised NSE levels returned to near normal after therapy. In patients with Stage IV-S disease serum NSE levels were significantly lower than those in Stage IV despite their extensive tumor burden. Serum NSE estimation may confirm Stage IV-S status and suggest a more benign clinical course.

An ultramicro bioluminescence assay of enolase: application to human cerebrospinal fluid

A highly sensitive method based on bioluminescence is described for the assay of enolase which can measure as little as 0.4 X 10(-6) IU of activity. This corresponds to an amount of enzyme present in 1-2 microliters of normal human cerebrospinal fluid and is therefore easily applicable to clinical samples of CSF which can only be obtained in very small amounts. The reproducibility of the method is very high within a broad range of enzyme concentrations and the assay is linear from 0.4 X 10(-6) IU up to at least 50 X 10(-6) IU of enzyme. This would permit application of the method to biological samples containing low as well as high enolase activities and especially for monitoring changes in enolase concentrations in the CSF and in the serum, as a function of pathological lesions in the central nervous system and other tissues.

Serum neuron-specific enolase in metastatic Merkel cell tumors

Three patients with widely disseminated Merkel cell tumors of the skin are presented. In all three cases, neuron-specific enolase (NSE) was demonstrated in neoplastic tissue by immunohistochemical staining, and serum NSE levels were also elevated in all three patients. Serum NSE may prove to be a useful tumor marker in this and other malignancies of neuroendocrine origin.

Immunohistochemical localization of neuron-specific enolase in gastroenteropancreatic neuroendocrine tumors. Correlation with tissue and serum levels of neuron-specific enolase

Neuron-specific enolase (NSE) was studied by immunohistochemistry and radioimmunoassay in ten gastroenteropancreatic (GEP) neuroendocrine tumors. Tissue and serum levels of NSE from the same patients were also analyzed. In all cases, NSE was localized by immunohistochemistry as diffuse cytoplasmic staining to neuroendocrine cells. Tissue levels of NSE were elevated in eight of ten cases while the serum level of NSE was elevated only in one patient with a metastatic gastrinoma to the liver. Examination of the distribution of NSE in a wide range of tumors (n = 55) showed that it is relatively specific for neurons and neuroendocrine tumors. Eight of ten tumors analyzed immunohistochemically for nine polypeptide hormones contained more than one hormone. Two of ten tumors with only one hormone were positive for NSE. The clinical syndrome in all cases was related to only one hormone. These results indicate that the immunohistochemical demonstration of NSE is a good general marker for the neuroendocrine system. While tissue levels of NSE in GEP neuroendocrine tumors are generally elevated, the serum levels of NSE may only be markedly elevated with extensive metastatic disease.

Immunocytochemical localization of neuron specific enolase in small cell carcinomas and carcinoid tumours of the lung

Carcinoid tumours and small cell carcinomas of the lung share many characteristics with normal neuroendocrine cells. While carcinoid tumours contain many dense-cored neurosecretory granules and are frequently argyrophil, small cell carcinomas are poorly granulated and rarely argyrophil, which casts doubt on their neuroendocrine nature. Immunostaining of the enzyme neuron specific enolase (NSE) was recently used to demonstrate the neuroendocrine components of the lung including nerves and neuroendocrine cells. We therefore used NSE immunostaining to investigate neuroendocrine differentiation in 79 lung tumours, including 18 bronchial carcinoids and 31 small cell carcinomas, and compared these results with those obtained with silver stains. Thirteen of the 18 carcinoids were reactive to silver, all other types being negative. NSE-immunoreactivity occurred in 16 carcinoids and 18 small cell carcinomas. None of the squamous cell carcinomas, large cell anaplastic carcinomas and adenocarcinomas examined showed NSE-immunoreactivity. Radioimmunoassay of extractable NSE from 10 fresh lung tumours correlated well with the immunostaining results, demonstrating large amounts in two small cell carcinomas (334 and 517 ng/mg protein) and three carcinoids (152, 908, and 1143 ng/mg protein). Values were much lower for four squamous cell carcinomas (31-44 ng/mg protein) and one large cell anaplastic carcinoma (30 ng/mg protein) and were accounted for by the presence of NSE-positive nerves and neuroendocrine cells in the surrounding lung. NSE immunostaining is a useful marker of neuroendocrine differentiation in lung tumours and should prove particularly valuable in the diagnosis of small cell anaplastic tumours and their metastases.

Morphologic, cytochemical and neurochemical characterization of the human medulloblastoma cell line TE671

Medulloblastoma cell line TE671 was characterized by morphologic, cytochemical, neurochemical, and growth criteria. In contrast to the uniform, in vivo histopathologic appearance of the tumor, TE671 in vitro exhibits six morphologic subtypes (Types I-VI) in varying percentages over 14 days in culture. TE671 grows as a monolayer by the merging of separate foci. Cells were positive for Periodic acid Schiff (PAS) and reticulum, and negative for the glial marker, glial fibrillary acid protein (GFAP). Receptors for human C3b (EAC) were present on 19% of the cells. Neural associated isoenzymes, neuron specific enolase (NSE) and creatine kinase (CK-BB) were demonstrated in TE671. Progeny of a single clonogenic cell manifested the morphologic heterogeneity of cell types (I-VI). The absence of markers specific for glial cells suggests that TE671 is an early (less differentiated) precursor. TE671, the only continuous human medulloblastoma cell line, provides an experimental model with which to compare and identify the subpopulation of neoplastic cells in medulloblastoma ex vivo.

Raised neuron-specific enolase in serum of children with metastatic neuroblastoma. A report from the Children's Cancer Study Group

Serum levels of neuron-specific enolase (NSE) were measured by radioimmunoassay at diagnosis in 122 children with widespread metastatic neuroblastoma (clinical stage IV). 96% of these patients had NSE levels more than three standard deviations above the mean for age-matched normal children. Mean serum NSE was 207 +/- SD257 ng/ml (range 10-1240 ng/ml), whereas that in normal age-matched children was 7.5 +/- 2.1 ng/ml (range 5.4-12.9 ng/ml). Analysis of survival in relation to the level of NSE at diagnosis suggested that serum levels greater than 100 ng/ml were associated with a poor outcome. This relation was highly significant in the subgroup of infants less than 1 year old at diagnosis; all 7 with serum NSE below 100 ng/ml were alive up to 36 months after diagnosis, whereas 7 of 8 with serum NSE above 100 ng/ml died within 12 months of diagnosis. Serum NSE may be a useful disease marker and a prognostic indicator in children with metastatic neuroblastoma.

Neuron-specific enolase and S-100 protein levels in cerebrospinal fluid of patients with various neurological diseases

Neuron-specific enolase (NSE) and S-100 protein (S-100) levels in cerebrospinal fluid (CSF) were determined in 129 patients with various neurological diseases. The chronological changes of these nervous system-specific proteins in CSF were also examined in 3 patients with acute disorders. NSE and S-100 levels were elevated in many cases with acute conditions. These specific proteins did not increase simultaneously but independently. These results suggested that NSE and S-100 in CSF would be useful markers for damage of the nervous system and that measurement of both NSE and S-100 might positively indicate whether the damage was neuronal, glial or mixed in origin. Moreover, from the serial determination of these substances, they would be better markers than cell counts and total protein in CSF for the active injury for the nervous tissues.

Intramural distribution of neuron specific enolase (NSE) in the human gastrointestinal tract

NSE concentrations were measured by radioimmunoassay in the main separated layers of the human gastrointestinal tract. At all levels, a similar pattern of distribution of this protein was found, primarily parallel to that of nerve elements. Lower amounts of NSE were detected in the separated mucosal epithelium, containing the endocrine cells.

Serum neuron-specific enolase: a serum marker for nonfunctioning pancreatic islet cell carcinoma

The isoenzyme, neuron-specific enolase (NSE) was evaluated as a serum marker for nonfunctioning pancreatic islet cell carcinoma. Serum NSE was measured by radioimmunoassay in 6 patients with islet cell cancer and in 22 healthy adults. Mean serum NSE in control subjects was 5 ng/ml (range 3.2 to 8.4 ng/ml). Three of six patients had clearly elevated serum NSE with values that ranged from 22 to 44 ng/ml. One patient had an equivocally elevated serum NSE of 9.2 ng/ml while receiving chemotherapy. When relapse occurred, the NSE level increased to 44 ng/ml. One of two patients with normal serum NSE had undergone radical pancreatectomy and had no evidence of disease when studied. Elevated serum NSE returned to normal limits after removal of all gross tumor in the only patient from whom a preoperative measurement was obtained. Results of this preliminary study suggest that serum NSE levels can aid in the diagnosis and monitoring of the course of nonfunctining islet cell carcinoma.

A developmental study of neuron-specific enolase in rat adrenal medulla

The levels of neuron-specific enolase (NSE) in rat adrenal medulla increase with age. A sharp increase was observed until the age of 15 days. At this time, the NSE level dropped slightly, followed by a gradual increase until the rats were 1 year old. The adrenal medullary NSE levels in males were higher than those observed in females. The difference was seen from 32 days of age, but was not statistically significant until 1 year. This study indicates that NSE can be used as a marker for differentiation in adrenal medulla, as it is used in the central nervous system and in neuroblastoma and pheochromocytoma cells.

Butyrate-induced increase in neuron-specific enolase and ornithine decarboxylase in anaplastic glioma cells

Butyrate treatment results in the rapid formation of processes on F98 anaplastic glioma cells. The morphological differentiation occurs more rapidly and to a greater extent than that induced by nerve growth factor (NGF). The incorporation of [3H]thymidine is virtually stopped 1 day after treatment of F98 cells with sodium butyrate. Butyrate also caused a large increase in ornithine decarboxylase activity in F98 cells between 6 and 12 h after treatment. This was inhibited by both cycloheximide and actinomycin-D. NGF did not cause these effects. Butyrate also caused an increase in neuron-specific enolase (NSE) content in F98 cells. This effect appeared to be specific for butyrate. Since NSE induction is characteristic only of neurons and neuroendocrine cells, this finding indicates that butyrate is capable of inducing biochemical differentiation along neuronal lines in undifferentiated glioma cells.

Increased nervous system-specific enolases in rat plasma and cerebrospinal fluid in bilirubin encephalopathy detected by an enzyme immunoassay

Three forms of enolase isozymes (alpha alpha, alpha gamma, gamma gamma), including nervous system-specific forms, were measured in the cerebrospinal fluid and the blood plasma of jaundiced or nonjaundiced infant rats by means of enzyme immunoassay systems capable of detecting each form of enolase at the 1 amol (10(-18) mol) level. Average enolase levels in cerebrospinal fluid in normal rat were 2.0, 0.2 and 0.1 pmol/ml for alpha alpha, alpha gamma, gamma gamma forms, respectively. Levels of alpha gamma and gamma gamma forms (nervous system-specific enolases; NSE) in jaundiced rats, which suffer Purkinje cell degeneration due to the inborn hyperbilirubinemia, were three to four times as high as the normal values. When kernicterus was induced in jaundiced rats by an injection of bucolome, the NSE level in cerebrospinal fluid was elevated up to more than 30-fold the control, together with a significantly higher level of alpha gamma form in blood plasma are helpful in detecting neuronal damage in the central nervous system.

High levels of immunoreactive nervous system-specific enolase in sera of patients with neuroblastoma

Serum levels of nervous system-specific enolase (NSE, gamma gamma form plus alpha gamma form) in patients with neuroblastoma and in control subjects were determined with a sensitive solid-phase sandwich enzyme immunoassay system. Serum levels of NSE in healthy adults ranged from 1.4-5.7 ng/ml (2.87 +/- 1.18 ng/ml, n = 20), and in control children (1-7 years old) from 2.6 to 10.8 ng/ml (5.76 +/- 2.42 ng/ml, n = 20). Serum samples (n = 13) from patients with neuroblastoma contained high levels of NSE, range 13.6 to 330 ng/ml (mean 96 ng/ml); however those (n = 7) from ganglioneuroblastoma patients were within a normal range (3.0-25.0 ng/ml; mean 8.3 ng/ml). These results suggested that the NSE in serum might be a valuable marker substance for screening and therapeutic monitoring of neuroblastoma.

Serum neuron-specific enolase: a marker for disease extent and response to therapy of small-cell lung cancer

Serum neuron-specific enolase (NSE) levels in 94 newly diagnosed untreated patients with small-cell lung cancer (SCLC) were compared with those in 30 adult controls. 38 of the SCLC patients had limited disease and 56 had extensive disease. Serum NSE was raised (greater than 12.0 ng/ml) in 69% of all patients (mean 52.35 +/- 11.56, range 4.1-850 ng/ml); it was raised in 15/38 (39%) of patients with limited stage disease and in 49/56 (87%) of those with extensive stage disease. Extensive stage patients had significantly higher mean NSE level (59 ng/ml) than did limited stage patients (13.8 ng/ml). Serum NSE was raised in 34/41 (84%) of patients with metastases at 1 or 2 sites and in all patients with metastases at 3 or more sites. Serial measurements in 23 patients receiving combination chemotherapy showed an excellent correlation between serum NSE and clinical response. Continuous cell-lines of SCLC, established from 10 of the patients in this study, all expressed high levels of NSE. These studies indicate that serum NSE may be a useful marker for staging and for monitoring response to therapy in patients with SCLC.

Nerve growth factor, laminin, and fibronectin promote neurite growth in human fetal sensory ganglia cultures

The effect of mouse nerve growth factor (NGF) on cultured human fetal sensory neurons was assayed by measuring neurite length, density and rate of growth. Addition of NGF increased adhesion of dissociated sensory neurons cultured on collagen coated surfaces. Almost all neurons of 9 to 10 week old fetuses are postmitotic, contain neuron-specific enolase, (an enzyme linked to differentiation), and require NGF for optimal neurite growth. Sensory ganglia re-explanted on collagen showed maximal neurite length and density when treated with 1 ng/ml of NGF. Neurite density was reduced considerably in the absence of mouse NGF and was almost abolished by addition of antimouse NGF antibodies. Surfaces coated with the matrix glycoproteins laminin or fibronectin further stimulated neurite growth of ganglia in the presence of NGF. Increasing amounts of matrix proteins could partly compensate for the absence of mouse NGF or the inhibition of NGF activity by antibodies. Stimulation of neurite growth by matrix proteins was time-dependent, and neurites showed maximum length at 10 days (2 to 3 mm). Neurite growth was more pronounced with laminin than with fibronectin and collagen, and antibodies to laminin suppressed all neurite growth. In the presence of a constant amount of NGF, mean neurite growth reached 26 microns/hr (at 1 day), and was 2.1 and 1.7 times faster on laminin and fibronectin (respectively) than on collagen. Thus, laminin, and to a lesser degree fibronectin, may enhance neurite growth of human sensory neurons in synergy with NGF.

Neuron specific enolase in human small cell carcinoma cultures

Continuous cell lines of human lung cancers were analyzed for neuron specific enolase (NSE). The levels of NSE in the small cell carcinoma cells were in every case much higher than those derived from other forms of lung cancer. Since NSE is strictly localized to neurons and neuroendocrine cells of the amine precursor uptake and decarboxylation (APUD) series, the data provided further evidence that small cell carcinoma is an APUD cell tumor and is distinct from other forms of lung cancer.

Brain levels of neuron-specific and nonneuronal enolase in Huntington's disease

Levels of the cell-specific brain isoenzymes of enolase were determined in basal ganglia and cerebral cortical tissue of Huntington's disease and age- and sex-matched control brain. Neuron-specific enolase (NSE) levels are decreased an average of 45% in basal ganglia from patients with Huntington's disease whereas the glial-specific form of enolase, nonneuronal enolase (NNE), is not significantly altered. In contrast, levels of NSE in cerebral cortical tissue from Huntington's disease patients remains unchanged in comparison with controls whereas NNE levels are significantly increased. NNE and NSE levels appear to be specific biochemical indicators of glial and neuronal cell number and viability. Levels of these cell-specific isoenzymes may therefore prove useful in quantitating neuropathological changes in various neurological disorders.

Increased levels of neuron-specific enolase in PC12 pheochromocytoma cells as a result of nerve growth factor treatment

Treatment of PC12 pheochromocytoma cells with nerve growth factor (NGF) resulted in increased levels of neuron-specific enolase (NSE). Neither insulin, growth hormone, cytochrome c, nor sodium butyrate increased NSE levels. Epidermal growth factor (EGF) did increase NSE levels, although not to the same extent as NGF. As little as 1 ng/ml NGF induced the maximal increase in NSE. As PC12 cells increased in density, the NSE levels increased even in untreated cells.