The 1H NMR Profile of Healthy Dog Cerebrospinal Fluid

The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using ¹H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the ¹H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies.     

Statistical integration of 1H NMR and MRS data from different biofluids and tissues enhances recovery of biological information from individuals with HIV-1 infection

Nuclear magnetic resonance (NMR) spectroscopy is widely used in metabonomics studies, but optimal recovery of latent biological information requires increasingly sophisticated statistical methods to identify quantitative relationships within these often highly complex data sets. Statistical heterospectroscopy (SHY) extracts latent relationships between NMR and mass spectrometry (MS) data from the same samples. Here we extend this concept to identify novel metabolic correlations between different biofluids and tissues from the same individuals. We acquired NMR data from blood plasma and cerebrospinal fluid (CSF) (N = 19) from HIV-1-infected individuals, who are known to be susceptible to neuropsychological dysfunction. We compared two computational approaches to SHY, namely the Pearson's product moment correlation and the Spearman's rank correlation. High correlations were observed for glutamine, valine, and polyethylene glycol, a drug delivery vehicle. Orthogonal projections to latent structures (OPLS) identified metabolites in blood plasma spectra that predicted the amounts of key CSF metabolites such as lactate, glutamine, and myo-inositol. Finally, brain metabolic data from magnetic resonance spectroscopy (MRS) measurements in vivo were integrated with CSF data to identify an association between 3-hydroxyvalerate and frontal white matter N-acetyl aspartate levels. The results underscore the utility of tools such as SHY and OPLS for coanalysis of high dimensional data sets to recover biological information unobtainable when such data are analyzed in isolation.     

Identification and Determination of Tele-Methylhistamine in Cerebrospinal Fluid by Gas Chromatography-Mass Spectrometry

Abstract: The presence of tele-methylhistamine in human cerebrospinal fluid has been established. The concentration was determined with the use of deuterated tele-methylhistamine. The preparation of the deuterated standard is described. The concentration range in samples from neuropsychiatric patients was 0.1-2.5 ng/ml. The structure of the pentafluoropropionyl derivative used for gas chromatography was studied with the aid of proton nuclear magnetic resonance spectroscopy.     

Cerebrospinal Fluid Measurements Suggest Precursor Availability and Sex Are Involved in the Control of Biogenic Amine Metabolism in a Primate

Biogenic amine precursors and metabolites were measured in cisternal cerebrospinal fluid from 83 female and 55 male vervet monkeys. The results indicate that mean rates of 5-hydroxytryptamine, dopamine, and noradrenaline metabolism in the brain are higher in females than in males. They also suggest that under physiological circumstances tryptophan availability is involved in the control of brain 5-hydroxytryptamine synthesis while tyrosine availability is involved in control of both dopamine and noradrenaline metabolism. The similarities seen between our results on vervets and those seen with human cerebrospinal fluid suggest that the vervet is a useful primate to study.     

Correlations between aminergic metabolites simultaneously obtained from human CSF and brain

Brain and cerebrospinal fluid (CSF) levels of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were simultaneously measured in 48 individuals at autopsy. Concentrations of 5-HIAA and HVA in the cerebral cortex were positively correlated with their levels in the CSF for the same individual. Additionally a positive correlation was observed between postmortem CSF levels of 5-HIAA and HVA and a significant concentration gradient for both metabolites was observed in serial fractions of CSF. These findings suggest that determinations of 5-HIAA and HVA in CSF from living individuals may reflect brain metabolite levels as well as the functional activity of these specific neuronal systems.     

IDENTIFICATION AND QUANTIFICATION OF 3-METHOXY -4-HYDROXYPHENYLLACTIC ACID (VLA) IN CEREBROSPINAL FLUID AND 3-METHOXY-4-HYDROXY PHENYLPYRUVIC ACID (VPA) IN THE URINE OF PARKINSONIAN PATIENTS TREATED WITH L-DOPA

The identification and quantification of 3-methoxy-4-hydroxyphenyllactic acid in cerebrospinal fluid, and 3-methoxy-4-hydroxyphenylpyruvic acid in the urine of Parkinsonian patients on medication with l -3,4-dihydroxyphenylalanine with or without a peripheral decarboxylase inhibitor are described. Data are also given for other catecholamine- and catecholamine precursor metabolites in urine and cerebrospinal fluid. Analyses were performed by means of gas chromatography with flame ionization or mass spectrometric detection. We have concluded that following the administration of l -3.4-dihydroxyphenylalanine + peripheral decarboxylase inhibitor. 3-methoxy-4-hydroxyphenyllactic acid must be considered as a quantitatively important metabolite of L-3.4-dihydroxyphenylalanine in cerebrospinal fluid. In addition, some comment is given on the presence of 3-methoxy-4-hydroxy-phenylpyruvic acid in the urine of these patients.     

Biological 1H NMR spectroscopy

Proton nuclear magnetic resonance spectroscopy (1H NMR) is a powerful analytical method used to identify and quantitate chemical compounds. In recent years, it has been used to study rates of metabolism in microbes, isolated perfused tissues, intact animals, and human beings. This review highlights some of the more recent biological applications of 1H NMR in the study of metabolic pathophysiology in animals and man. 1H NMR can rapidly analyze complex mixtures of metabolites found in body fluid and biopsy specimens. In vivo 1H NMR methods can measure intracellular pH, a wide variety of metabolites, tissue perfusion, and rates of metabolism of endogenous and exogenous compounds. Using 13C labeled compounds or magnetization transfer techniques metabolic fluxes may be measured in vivo during virtually all normal and abnormal physiological conditions.     

Magnetic resonance spectroscopy of cancer metabolism and response to therapy

Magnetic resonance spectroscopy allows noninvasive in vivo measurements of biochemical information from living systems, ranging from cultured cells through experimental animals to humans. Studies of biopsies or extracts offer deeper insights by detecting more metabolites and resolving metabolites that cannot be distinguished in vivo. The pharmacokinetics of certain drugs, especially fluorinated drugs, can be directly measured in vivo. This review briefly describes these methods and their applications to cancer metabolism, including glycolysis, hypoxia, bioenergetics, tumor pH, and tumor responses to radiotherapy and chemotherapy.     

Determination of melarsoprol in biological fluids by high-performance liquid chromatography and characterisation of two stereoisomers by nuclear magnetic resonance spectroscopy

The analysis of melarsoprol in whole blood, plasma, urine and cerebrospinal fluid is described. Extraction was made with a mixture of chloroform and acetonitrile followed by back-extraction into phosphoric acid. A reversed-phase liquid chromatography system with ultraviolet detection was used. The relative standard deviation was 1% at concentrations around 10 μmol/l and 3–6% at the lower limit of determination (9 nmol/l in plasma, 93 nmol/l in whole blood, 45 nmol/l in urine and 10 nmol/l in cerebrospinal fluid). Melarsoprol is not a stable compound and samples to be stored for longer periods of time should be kept at −70°C. Plasma samples can be stored at −20°C for upt to 2 months. Chromatography showed that melarsoprol contains two components. Using nuclear magnetic resonance spectroscopy the two components were shown to be diastereomers which slowly equilibrate by inversion of the configuration at the As atom.     

24-hour cerebrospinal fluid levels of vasopressin in hydrocephalic patients

The variation in vasopressin concentrations of ventricular cerebrospinal fluid and plasma throughout a 24-h period was studied in 10 patients with hydrocephalus. In 6 control patients, the diurnal variation in plasma vasopressin concentrations was studied. Vasopressin concentrations were determined by radioimmunoassay in plasma and in extracted and unextracted cerebrospinal fluid. Cortisol and osmolality in plasma were also measured. Vasopressin concentrations measured in extracted cerebrospinal fluid showed only small intra- and interindividual variation, while the corresponding values for unextracted cerebrospinal fluid were 2-5-fold higher and showed more variation. Plasma vasopressin concentrations varied considerably throughout the 24-h period in the individual hydrocephalic patient and between the patients. The pattern of variation was inconstant with no circadian rhythm, and the variation was not related to any changes in plasma osmolality, blood pressure or intracranial pressure. In some of the patients, the normal diurnal pattern of variation in plasma cortisol was broken, however, without a relation to the observed fluctuations in vasopressin concentrations. The abnormal variation of plasma vasopressin and cortisol was considered to reflect stress in connection with the intracranial pressure monitoring procedure. In the control patients, plasma vasopressin showed only small variations and plasma cortisol showed a normal diurnal rhythm. It is concluded that cerebrospinal fluid vasopressin concentration in patients with hydrocephalus is very constant throughout the day, even when plasma vasopressin concentrations show marked episodic increases. Thus, a circadian rhythm in the cerebrospinal fluid vasopressin concentration, as reported in several animal species, could not be confirmed in these patients.     

Monoamine metabolites in human cerebrospinal fluid: indicators of neuronal activity?

Concentrations of monoamine metabolites in human cerebrospinal fluid (CSF) have been widely used as indicators of the level of functional activity in the central monoaminergic neuronal pathways. This article reviews the relationship between the turnover of the neurotransmitter monoamines noradrenaline, serotonin, and dopamine, and the concentrations in CSF of their principal metabolites, 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA). It attempts to summarise what is known of the effects of various illnesses and drug treatments on the concentrations of these metabolites.     

Effects of cerebrospinal fluid preparation from male and female patients with opiate dependence on rat open-field behavior

The effects of the intranasal administration of preparations made from the cerebrospinal fluid of male and female opiate users on the open-field rat behavior were studied. Behavioral differences were demonstrated in the effects of preparations from female and male cerebrospinal fluid. The administration of the "male" preparation produced a significant decrease in the locomotor activity and increase in the immobilization time and grooming duration, while the "female" preparation had the opposite effects. These differences may result from different content of endogenous and exogenous opiates and dopamine (and its metabolites) in the cerebrospinal fluid of male and female opiate users.     

Nitrite reduces cytoplasmic acidosis under anoxia

The ameliorating effect of nitrate on the acidification of the cytoplasm during short-term anoxia was investigated in maize (Zea mays) root segments. Seedlings were grown in the presence or absence of nitrate, and changes in the cytoplasmic and vacuolar pH in response to the imposition of anoxia were measured by in vivo (31)P nuclear magnetic resonance spectroscopy. Soluble ions and metabolites released to the suspending medium by the anoxic root segments were measured by high-performance liquid chromatography and (1)H nuclear magnetic resonance spectroscopy, and volatile metabolites were measured by gas chromatography and gas chromatography-mass spectrometry. The beneficial effect of nitrate on cytoplasmic pH regulation under anoxia occurred despite limited metabolism of nitrate under anoxia, and modest effects on the ions and metabolites, including fermentation end products, released from the anoxic root segments. Interestingly, exposing roots grown and treated in the absence of nitrate to micromolar levels of nitrite during anoxia had a beneficial effect on the cytoplasmic pH that was comparable to the effect observed for roots grown and treated in the presence of nitrate. It is argued that nitrate itself is not directly responsible for improved pH regulation under anoxia, contrary to the usual assumption, and that nitrite rather than nitrate should be the focus for further work on the beneficial effect of nitrate on flooding tolerance.     

Neuropeptides in human cerebrospinal fluid

Ten neuropeptides were measured by RIA in human cerebrospinal fluid obtained from 30 normal volunteers. The levels of seven peptides (corticotropin releasing factor, adrenocorticotropin, vasoactive intestinal peptide, somatostatin, beta-endorphin, beta-lipotropin, and the N-terminal fragment of proopiomelanocortin) were highly, positively correlated with one another. This result is consistent with the hypothesis that cerebrospinal fluid levels of these seven peptides are a function of some common regulatory factor, such as shared release into the cerebrospinal fluid.     

Protein identification in cerebrospinal fluid using packed capillary liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry

The identification and characterization of proteins in complex biological samples such as body fluids, require powerful and reliable tools. Mass spectrometry is today one of the most important methods in such research. This paper reports on the results from the first experiment where a tryptic digest of cerebrospinal fluid was analyzed applying reversed phase liquid chromatography coupled on-line to a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer. In total, 70 204 peaks were detected, which originated from 16 296 isotopic clusters corresponding to 6551 unique peptide masses. From these masses, 39 proteins were identified in the sample. The amount of sample required for one experiment corresponds to 32 microL of cerebrospinal fluid.     

Amino Acids in Plasma and CSF and Monoamine Metabolites in CSF: Interrelationship in Healthy Subjects

Plasma and cerebrospinal fluid (CSF) concentrations of amino acids were measured in 65 healthy volunteers (50 men and 15 women). The CSF levels of the monoamine metabolites homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylethylene glycol (MOPEG), and 5-hydroxyindoleacetic acid (5-HIAA) were also determined. Sex differences were observed in both plasma and CSF amino acid levels as well as in the relationship between these concentrations. No significant correlations were observed between the CSF levels of HVA and 5-HIAA, and the concentrations of their precursor amino acids in either plasma or CSF. The MOPEG level in CSF correlated positively with the plasma concentrations of several amino acids.     

A branched-chain organic acid linked to multiple sclerosis: first identification by NMR spectroscopy of CSF

(1)H NMR spectroscopy of cerebrospinal fluid (CSF) is currently being used to study metabolic profiles characteristic of distinct multiple sclerosis (MS) manifestations. For select MS patient groups, we have previously detected significantly increased concentrations of several identified metabolites and one unidentified compound. We now present, for the first time, the identification of the latter molecule, beta-hydroxyisobutyrate (BHIB). A combination of dedicated 1D and 2D (1)H NMR experiments was employed for signal assignment. To our knowledge, BHIB has not previously been identified in (1)H NMR spectra of biofluids or biological tissues. Our assignment suggests new biochemical pathways involved in specific MS pathologies.     

Tumefactive multiple sclerosis requiring emergent biopsy and histological investigation to confirm the diagnosis: a case report

Introduction

Tumefactive multiple sclerosis is a demyelinating disease that demonstrates tumor-like features on magnetic resonance imaging. Although diagnostic challenges without biopsy have been tried by employing radiological studies and cerebrospinal fluid examinations, histological investigation is still necessary for certain diagnosis in some complicated cases.

Case presentation

A 37-year-old Asian man complaining of mild left leg motor weakness visited our clinic. Magnetic resonance imaging demonstrated high-signal lesions in bilateral occipital forceps majors, the left caudate head, and the left semicentral ovale on fluid-attenuated inversion recovery and T2-weighted imaging, and these lesions were enhanced by gadolinium-dimeglumin. Tumefactive multiple sclerosis was suspected because the enhancement indistinctly extended along the corpus callosum on magnetic resonance imaging and scintigraphy showed a low malignancy of the lesions. But oligoclonal bands were not detected in cerebrospinal fluid. In a few days, his symptoms fulminantly deteriorated with mental confusion and left hemiparesis, and steroid pulse therapy was performed. In spite of the treatment, follow-up magnetic resonance imaging showed enlargement of the lesions. Therefore, emergent biopsy was performed and finally led to the diagnosis of demyelinating disease. The enhanced lesion on magnetic resonance imaging disappeared after one month of prednisolone treatment, but mild disorientation and left hemiparesis remained as sequelae.

Conclusions

Fulminant aggravation of the disease can cause irreversible neurological deficits. Thus, an early decision to perform a biopsy is necessary for exact diagnosis and appropriate treatment if radiological studies and cerebrospinal fluid examinations cannot rule out the possibility of brain tumors.     

IDENTIFICATION AND QUANTIFICATION OF 3-METHOXY-4-HYDROXYPHENYLETHANOL (MOPET) IN HUMAN CEREBROSPINAL FLUID AND RAT BRAIN BY MEANS OF GAS CHROMATOGRAPHY-MASS SPECTROMETRY

Abstract— The identification of 3-methoxy-4-hydroxyphenylethanol (MOPET) in human cerebrospinal fluid and in rat brain is described. Use was made of the high sensitivity and selectivity provided by gas chromatography-mass spectrometry. Concentrations of MOPET in human cerebrospinal fluid, rat brain and rat urine together with those of some other catecholamine metabolites are given. The effect of intraperitoneal administration of deuterium-labelled MOPET and haloperidol on rat brain and urine MOPET levels was studied. The quantitative importance of MOPET as an end product of central and peripheral dopamine metabolism in man and rat is discussed.