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Background: Metabolic syndrome becomes a focus of clinical cares to people living with HIV (PLHIV) globally. This study aimed to explore the metabolic profiles in cerebrospinal fluid (CSF) of Chinese people living with HIV (PLHIV)., Methods: Cerebrospinal fluid samples from PLHIV and healthy controls were collected from our hospital. Then, the metabolic profiles of CSFs were analyzed PLHIV with healthy individual as the normal controls using the untargeted GC/TOFMS. Following this, kyoto encyclopedia of genes and genomes annotation and pathway analysis were performed to further explore the underlying mechanism of these metabolic alterations in cognitive impairment of PLHIV., Results: Both PCA analysis and OPLS-DA had presented that most samples were localized in 95% CI and the gap between control and HIV could significantly separate from each other. Upon this quality control, a total of 82 known metabolites were identified in CSF between PLHIV and healthy controls. Clustering of these metabolites presented that these differentially expressed metabolites could markedly distinguish HIV from healthy controls. Further pathway analyses showed that TCA cycle (citric acid, fumaric acid, lactate, et al.), amino acid (arginine, proline, alanine, aspartate, glutamine, et al.), lipid (cholesterol, butyrate, et al.) metabolisms were significantly changed in CSF of PLHIV, which might affect the cognitive status of PLHIV via affecting neuron energy support, signaling transduction, and neuroinflammation., Conclusion: Metabolic profiles were significantly altered in CSF and might play key roles in the etiology of cognitive impairment of PHLIV. Further explore the exact mechanism for these metabolic changes might be useful for cognitive impairment management of PHLIV., (© 2021 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

The present study was conducted to determine the concentration of amino acids in the cerebrospinal spinal fluid (CSF) and the activities of two tramsaminases: glutamic oxaloacetate transaminase (GOT) and glutamic pyruvate transaminase (GPT) in human Alzheimer disease (AD) and normal brain. L-glutamic acid, L-glutamine and L-alanine are the most abundant amino acids in the CSF (50-55% of total amino acids). L-glutamine occurs at much higher levels in Alzheimer CSF compared to the normal CSF (229+/-91.8 nmol/ml in AD versus 107+/-47.2 nmol/ml in normal; P=0.0041). In contrast, L-aspartate occurs at significantly lower concentrations in Alzheimer CSF than normal CSF (46.1+/-25.7 nmol/ml in Alzheimer versus 95.2+/-52.6 nmol/ml in normal; P=0.020). In Alzheimer brain (frontal, parietal and occipital cortices) GOT is present at significantly higher activities than in normal brain cortices (about 1.5 times higher; P<0.01). No significant differences for GPT activity occurred between normal and AD brain. Since CSF receives amino acids from brain tissues, and since GOT catalyzes the conversion of L-aspartate to L-glutamate, the higher concentrations of L-glutamine (which is derived from L-glutamate), and the lower concentrations of L-aspartate found in Alzheimer CSF could be considered as a consequence of the higher activity of GOT that occurs in Alzheimer brain.

The laboratory examination of cerebrospinal fluid (CSF) continues to play an important role in the clinical diagnosis and treatment of various disorders of the central nervous system (CNS). The major conditions currently include, as they have in the past, infectious diseases, neoplastic processes, multiple sclerosis, other demyelinating disorders, and intracerebral hemorrhage. Recent publications suggest a variety of new laboratory tests that may be useful in the evaluation of patients with both primary and metastatic malignancies, Alzheimer's disease, Creutzfeld-Jacob disease, global ischemia, various psychiatric disorders, CSF otorrhea and rhinorrhea, and in the differential diagnosis of cortical vs lacunar stroke, among others. Examples of these recent developments and their possible clinical usefulness are discussed.

A new approach was developed to minimize inevitable damage to nervous and meningeal tissue due to implantation of a sampling tube allowing multiple withdrawal of cerebrospinal fluid (CSF) from the cisterna magna in adult rats. A tube was secured on the atlanto-occipital membrane. Thereafter, a hole was cut through the membrane, allowing flow of CSF from the cisterna magna to the tube. CSF could be sampled repeatedly for at least 1 week. There was no blood-brain barrier damage. The pressure in the cisterna magna remained normal as did the estimated rate of CSF formation. Very few blood cells contaminated the CSF. There was very little evidence of inflammation. The nervous tissue was undamaged as shown by exclusion of a dye-protein complex. The CSF concentrations of the cytosolic neuronal protein neuron-specific enolase (NSE), and of the astrocyte protein S-100 were very low. The pattern of amino acids remained within normal limits. Scanning electron microscopy revealed that clot and reactive changes were restricted to the vicinity of the connecting hole. We conclude that our approach to positioning a tube on the atlanto-occipital membrane and then connecting it to the cisterna magna reproducibly and reliably enables 'atraumatic' multiple sampling of CSF.

This study describes a standardized method for recording single-pulse 1H-nuclear magnetic resonance (1H-NMR) spectra from cerebrospinal fluid (CSF). Quantitative data for alanine, valine, threonine, and lactic acid correlated well with data obtained with conventional techniques. The pH of the samples is important for the reproducibility of the chemical shift of resonances, and should be standardized to improve recognition and assignment of resonances. A database of resonances from various metabolites is presented. Fifty compounds could be identified in CSF, 15 of which had not been observed earlier in NMR studies of CSF. We describe for the first time in the literature, to our knowledge, 3-hydroxyisovaleric acid as a regular component of many CSF samples. As examples of the diagnostic power of the technique, spectra are shown of CSF from patients with three different inborn errors of metabolism. We found high concentrations of N-acetylaspartic acid, citric acid, and succinic acid in CSF from a patient with Canavan disease. This is indirect evidence for the existence of a carrier mechanism that is shared by these di- and tricarboxylic acids.

Capillary electrophoresis with laser-induced fluorescence detection is used to analyze 10 microL samples of human cerebrospinal fluid. Primary amine-containing compounds in untreated cerebrospinal fluid are labeled with 3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde prior to analysis, producing fluorescent isoindoles. Electropherograms containing approximately 50 peaks are obtained in less than 35 min from cerebrospinal fluid samples. Ten peaks in the electropherograms have been identified and quantitated: arginine, glutamine, threonine, valine, gamma-amino-n-butyric acid, serine, alanine, glycine, glutamic acid, and aspartic acid. Detection limits for these 10 amino acids range from 0.29 nM for gamma-amino-n-butyric acid to 100 nM for threonine, and separation efficiencies as high as 190,000 theoretical plates are obtained for these analytes. Electropherograms of cerebrospinal fluid samples from patients with Alzheimer's disease and from children with different neurological disorders are compared to those of healthy controls. Differences in individual amino acid levels are observed between the patient groups, and these differences appear to be disease and age related. These results indicate that analysis of cerebrospinal fluid by capillary electrophoresis will be useful as a selective, rapid, and sensitive tool for both diagnosis of central nervous system disorders and for study of the mechanisms of these disorders.

Extensive assignments of resonances in the 600 MHz 1H-NMR spectra of cerebrospinal fluid are reported. These have been achieved by the measurement of a combination of two-dimensional experiments comprising homonuclear J-resolved, COSY45, and double-quantum filtered COSY (DQCOSY) spectra. By these means the previous total of 18 endogenous metabolites, of which in general only selected resonances have been assigned, has been augmented to 46 molecules including all of the resonances of both alpha- and beta-anomers of glucose. With only a few exceptions all resonances have been assigned for all of the metabolites. In addition, the effect of freeze-drying on the 600 MHz 1H-NMR spectrum of human cerebrospinal fluid (CSF) is presented using both lyophilization with reconstitution into either H2O or D2O. Freeze-drying and reconstitution into H2O causes a significant sharpening of many small molecule resonances, including notably those of glutamate and glutamine as well as other amino acids and in addition causes the loss of volatile components, principally acetone. Further exchange of the H2O solvent by D2O causes no additional changes in the spectra.

As far as the pathogenesis of poisonings with organophosphorus pesticides is concerned, in addition to irreversible inhibition of acetylcholinesterase (AGE) in tissues, of importance are changes in the other systems which essentially determine the outcome of intoxication. The purpose of the present study was to examine the nature of changes occurring in total protein and protein fractions, free amino acids (aspartic and glutamic acids, glycine, isoleucine, leucine) and in certain enzymes (AST, ALT, CP, GGTP, GDH) in the cerebrospinal fluid (CSF) of patients with acute Malathion insecticide poisoning. 137 patients aged 20 to 50 years were placed under observation. There were 77 men and 60 women. 40 persons had poisoning of medium gravity and 97 were severely poisoned. The intake of the CSF was performed on days 1, 3, 10, 14 and 21 since the disease onset. It has been established that in acute Malathion insecticide poisoning, the CSF content of the stimulating mediator amino acids, aspartic and glutamic, rises within the early periods, whereas the concentration of the inhibitory mediator glycine decreases. The changes in protein fractions of the CSF are characterized by a fall of the content of globulins and a rise of albumins, thus attesting to the predominance of pathological processes in the brain, especially in the initial period of intoxication, and to the impairment of the blood-brain barrier. The development of intoxication is associated with activation in the CSF of LDN, CP, GGTP and GDH as well as by activation of LDH isozymes which is viewed as the result of the membranotoxic effect of a Malathion insecticide.

Sampling and HPLC analysis procedures for CSF amino acid determination were evaluated. It is recommended to analyse native CSF. The sample should be taken from the first 12 ml obtained by lumbar puncture. Amino acid concentrations are stable for short periods over a wide range of temperature however, storage at -70 degrees to -80 degrees C is recommended. With the precolumn derivatization and a 30 cm reverse-phase column, the separation and reproducibility are reliable for analyses in the daily hospital routine.

Amino compounds were measured with an amino acid analyzer in the fasting plasma of 34 patients with childhood psychoses (28 having infantile autism) and 40 control children, and in the cerebrospinal fluid (CSF) of 19 of the psychotic children and 23 control children. Organic acids were determined by gas chromatography in urine, plasma, and CSF of the psychotic patients. The mean concentration of ethanolamine in CSF was significantly higher in psychotic children than in control subjects. A subgroup of autistic children may possibly have a brain disorder involving ethanolamine metabolism. None of the known inherited diseases of organic acid metabolism was found in any of the psychotic children, but future studies utilizing sophisticated gas chromatography--mass spectrometry--computer techniques might disclose abnormal organic acid content in the CSF of such patients.

Fluid from the notochordal canal of the coelacanth, Latimeria chalumnae, was analyzed for major inorganic and organic constituents and compared with blood serum from the same fish. Significantly or suggestively lower levels of sodium, magnesium, calcium, bicarbonate, sulfate, total carbohydrates, glucose, lactate, cholesterol, bound phosphate and total proteins were found in notochordal fluid than in serum, whereas potassium, chloride, urea, trimethylamine oxide, and total free amino acids were higher and inorganic phosphorus essentially identical. Osmolarity of notochordal fluid (1058 mOsm) exceeds that of serum (942 mOsm). A whitish precipitate in the fluid consisted of a matrix of fibers 100 A in diameter and of indefinite length. It resembled a sialoglycoprotein in composition and was stabilized by disulfide bonds. The fluid contained cellular debris.

The degree of contamination by blood in macroscopically clear cerebrospinal fluid (CSF) from the rat was assessed by the red blood cell count. Amino acid concentrations in the same samples were determined using high performance liquid chromatography. A significant positive correlation between the number of erythrocytes and amino acid concentration was found for alanine, asparagine, aspartate, citrulline, glutamate, glycine, phenylalanine and taurine but not for glutamine, histidine, isoleucine, leucine, lysine, methionine, ornithine, serine, threonine, tyrosine and valine. The difference in amino acid concentration between samples that were or were not contaminated by blood was as much as one order of magnitude for aspartate, glutamate, glycine and taurine; the concentrations of these amino acids were highly correlated with the erythrocyte counts (r = 0.87, P = 0.000002 for glutamate). The results suggest that macroscopical inspection is often not sufficient to judge contamination by blood in the CSF.

The advent of very sensitive and rapid agglutination tests has been a major advance in facilitating the rapid diagnosis of bacterial meningitis (Table 3). Future investigations will focus on the use of monoclonal antibodies that have been found to be more sensitive and specific than polyclonal antiserums. Modifications of enzyme immunoassays of bacterial antigens to improve speed and technical reliability are in progress. The day may come with the present advances in technology that within 1 hour of receiving a CSF specimen, both the identity and antimicrobial sensitivity of the invading pathogen will be known to the physician. In addition, through quantitation of bacterial antigen, a reliable prognosis as to the outcome of the treated meningitis will also be possible. Finally, the continued refinement of reliable antiserums to group B Neisseria meningitidis, as well as other bacteria responsible for meningitis, particularly in the immunocompromised host will occur.