Cerebrospinal fluid 'neuronal thread protein' comes from serum by passage over the blood-brain barrier.

Cerebrospinal fluid (CSF) biochemical markers for Alzheimer's disease (AD) would be of great value, both to improve clinical diagnostic accuracy and to increase our knowledge of the pathogenesis of the disorder. An increase in the CSF-level of 'neuronal thread protein' (pancreatic thread protein (PTP) immunoreactive material in the brain) has been suggested to be just such a biochemical marker. We have studied CSF 'neuronal thread protein'-like immunoreactivity (NTPLI) using a microparticle enzyme immunoassay. CSF-NTPLI did not differ significantly between AD type I (pure AD) and controls, but was significantly higher in AD type II (senile dementia) and vascular dementia (VAD) as compared with controls. Signs of blood-brain barrier (BBB) damage (elevated CSF/S albumin ratio) were found in both AD type II and in VAD, but not in AD type I. In a multiple ANOVA, with age and CSF/S albumin ratio as covariates, no significant difference in CSF-NTPLI between diagnostic groups was noted though both CSF/S albumin ratio and age (P < 0.0001 and P < 0.001 respectively) were found to influence the CSF-NTPLI level. Since BBB function was found to influence the CSF-NTPLI level, we examined whether NTPLI was present in serum. Indeed, serum NTPLI was about 40 times higher than CSF-NTPLI in neurological patients. Moreover, there was a statistically significant correlation between S-NTPLI and CSF-NTPLI. Taken together, present findings suggest that most of NTPLI in CSF comes from the serum, by passage over the BBB.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentration of neural thread protein in cerebrospinal fluid from progressive supranuclear palsy and Parkinson's disease.

We measured the concentration of neural thread protein (NTP) in cerebrospinal fluid (CSF) by an automatized microparticle enzyme immunoassay from 11 progressive supranuclear palsy (PSP) patients and 11 Parkinson's disease (PD) patients and 7 patients with cervical spondylosis as controls. The mean levels did not differ significantly among the groups. In the PSP group, however, the levels correlated significantly with the severity of motor symptoms, signs and functional disability but not with dementia, while the opposite was true in the PD group. The elevated levels in PSP cases may reflect an increase with progression of the disease in such pathological structures as neurofibrillary tangles or neuropil threads, while in PD such levels may indicate associated Alzheimer-type pathology.

Distribution of Alzheimer's disease-associated protein (ADAP) in 10 human brains.

ALZ50-based enzyme immunoassay was used to study distribution of Alzheimer's disease-associated protein (ADAP) in postmortem brain tissues of 5 Alzheimer's disease (AD) and 5 non-Alzheimer's disease (NAD) subjects. There are at least three AD-associated proteins, including A68. Levels are higher in brain regions with severe neuronal loss in AD: frontal, temporal, hippocampal cortex, and amygdala. No significant ADAP was found in the NAD samples (from 2 age-matched-1 clinically demented-and 3 younger subjects). ADAP levels in four regions of AD brains were not correlated to neuritic plaque count in corresponding regions of matching formaldehyde-fixed hemispheres.

Automated microparticle enzyme immunoassay for neural thread protein in cerebrospinal fluid from Alzheimer's disease patients.

An automated microparticle enzyme immunoassay (MEIA) with the IMx analyzer for the detection of neural thread protein (NTP) in cerebrospinal fluid (CSF) from Alzheimer's disease (AD) patients was developed. This assay uses monoclonal antibodies produced against the purified pancreatic form of the protein. The assay employs one monoclonal antibody covalently coupled to the microparticle to capture immunoreactive material in CSF or brain tissue. The second monoclonal antibody was conjugated to alkaline phosphatase and serves as detection antibody. The assay provides results in approximately 45 minutes with a sensitivity of 60 pg/ml (3 fmoles/ml). The titration curve of both normal and AD CSF resulted in a linear relationship with respect to the volume of CSF used. A similar relationship was observed when normal and AD brain tissue extracts were serially diluted. The molecular weight of NTP in CSF was approximately 20 kD as determined by gel filtration method under non-denaturing conditions. The recovery for pancreatic thread protein (PTP) spiked in either normal or AD CSF was 104% and 108%, respectively. Intra-, inter-, and total assay CVs (coefficient of variation) for controls were less than 2.9%, 3.3% and 3.0%, respectively. This assay will provide a useful tool in the study of the Alzheimer's disease and may help research in diagnosis and prognosis of Alzheimer's disease and related disorders.

Detection of amyloid beta protein precursor immunoreactivity in normal and Alzheimer's disease cerebrospinal fluid.

The amyloid A4 (or beta protein), a 4.2 kD polypeptide, is a major component of amyloid deposits in the brains of patients with Alzheimer's Disease (AD). The self-aggregating amyloid A4 protein of AD is encoded as part of three larger proteins by the amyloid A4 precursor gene. The corresponding proteins have 695, 751 and 770 amino acid residues. To investigate the utility of amyloid beta protein precursor (A beta PP) as a diagnostic marker for AD an antiserum against a synthetic peptide (175-186), predicted from cDNA sequence for A beta PP, was used. The immunoreactivity of A beta PP in normal and AD cerebrospinal fluid (CSF) was measured by Western blot and detected with radiolabeled protein A. A total of fifty-seven CSF samples (AD = 27 and normal = 30) were analyzed for A beta PP immunoreactivity. A polyclonal antibody detected two major protein bands with apparent molecular weights of 105kD and 90kD both in normal and AD CSF. The difference between normal and AD CSF was not significant. These results indicate that immunoreactivity of A beta PP is present both in normal and AD CSF, and that the difference is too small to be used as a diagnostic marker.

Non-esterified long-chain fatty acid metabolism in fed sheep at rest and during exercise.

The role of circulating, non-esterified, long-chain fatty acids (NEFA) as a source of energy for the whole animal and skeletal muscle was investigated in fed non-pregnant sheep at rest and during exercise. Infusion of tracer quantities of [1-14C]oleic or [1-14C]stearic acid was combined with the use of arteriovenous difference studies on fed sheep at rest or during a 2 h period of exercise on a belt treadmill moving at 4.5 km h-1. At rest all parameters of NEFA metabolism indicated a minimal role for oxidation. Thus the concentration in plasma (0.07 +/- 0.01 mmol l-1), entry rate (0.08 +/- 0.02 mmol h-1 kg-1 body wt), contribution to whole animal oxidation (1.2 +/- 0.3%) and utilization of NEFA by skeletal muscle (0.046 +/- 0.008 mmol h-1 kg-1 muscle) were all low. Exercise prompted a shift to lipolysis and accordingly the above parameters increased markedly some 13-24-fold. The circulating concentration of ketone bodies showed only a small increase during exercise and consequently the role of ketone bodies as an energy source during exercise was minimal. Glucose utilization by skeletal muscle was considerable in animals at rest and it represented the most significant potential fuel of skeletal muscle. Exercise resulted in a sustained increase of 3-4-fold in the utilization of glucose by skeletal muscle. Thus the traditional view that NEFA and not glucose is a predominant fuel of skeletal muscle of fed sheep should be appraised.