Ribose-5-phosphate isomerase deficiency: new inborn error in the pentose phosphate pathway associated with a slowly progressive leukoencephalopathy.

The present article describes the first patient with a deficiency of ribose-5-phosphate isomerase (RPI) (Enzyme Commission number 5.3.1.6) who presented with leukoencephalopathy and peripheral neuropathy. Proton magnetic resonance spectroscopy of the brain revealed highly elevated levels of the polyols ribitol and D-arabitol, which were subsequently also found in high concentrations in body fluids. Deficient activity of RPI, one of the pentose-phosphate-pathway (PPP) enzymes, was demonstrated in fibroblasts. RPI gene-sequence analysis revealed a frameshift and a missense mutation. Recently, we described a patient with liver cirrhosis and abnormal polyol levels in body fluids, related to a deficiency of transaldolase, another enzyme in the PPP. RPI is the second known inborn error in the reversible phase of the PPP, confirming that defects in pentose and polyol metabolism constitute a new area of inborn metabolic disorders.

L-Arabinosuria: a new defect in human pentose metabolism.

A female patient, the first child of healthy non-consanguineous parents, presented at the age of 16 months with delayed motor development and facial dysmorphism. In addition she displayed a palatoschizis and multiple skeletal abnormalities as hypoplastic scapulae, hypoplastic os ilea, and an extreme cervical kyphosis. Biochemical investigation of urine revealed no abnormalities except for the presence of large amounts of reducing sugars. The sugar was identified as L-arabinose, which mainly originated from fruit formula in her diet. In addition highly elevated levels of L-arabitol were found in urine, plasma, and cerebrospinal fluid. Although little is known about human arabinose metabolism, we presume that L-arabitol dehydrogenase is deficient in our patient. As polyols are potentially toxic to the central nervous system there could be deleterious long-term effects of this disorder. Withdrawal of dietary fruit led to normalization of polyol levels. The above-mentioned clinical abnormalities are probably not related to this new inborn error of metabolism and should be considered as a separate entity.

[Gas chromatography in express diagnosis of candidiasis and monitoring of antifungal therapy efficacy by D-arabinitol and mannose levels in pediatric patients]. / Gazokhromatograficheskaia ékspress diagnostika kandidoza i monitoring éffektivnosti protivogribkovoi terapii po urovniu D-arabinitola i mannozy u detei.

Seventy three children (40 blood and 43 liquor specimens) were examined with the use of gas chromatography (GC) to detect background concentrations of Candida metabolites. The criterium of the children enrollment to the control group was the absence of the clinical and laboratory signs of the fungal infection. The normal contents of the fungus metabolites were considered to be 0.51 +/- 0.28 microgram/ml for D-arabinitol and 17.7 +/- 10.4 micrograms/ml for mannose in the serum and 7.24 +/- 3.04 micrograms/ml for D-arabinitol and 67.1 +/- 47.4 micrograms/ml for mannose in the liquor. Fifty four children at the age of 1 month to 12 years with the signs of the fungal infection requiring systemic antifungal therapy were also examined. Prior to the use of antifungal drugs the routine microbiological tests and GC detection of the fungus metabolites were performed. The fungus was isolated with the cultural method from the blood in 2 patients (6.3 per cent), from the mucosa in 25 (71.4 per cent) out of 32 patients with fungal complications at the background of cytostatic therapy and neutropenia, from the liquor in 3 (21.4 per cent) out of 14 patients with meningitis and from the urine in 8 (100 per cent) out of 8 patients with urinary infection. The GC examination revealed increased levels of the Candida metabolites in 96 per cent of the children. A favourable time course of the infection at the background of amphotericin B or fluconasol use was recorded by the clinical indices which correlated with a reliable decrease of the contents of D-arabinitol and mannose to the normal. The use of GC is recommended in express diagnosis of candidiasis especially when the results of the cultural tests are negative as well as in monitoring of the fungal therapy efficacy.

Cerebrospinal fluid and plasma distribution of myo-inositol and other polyols in Alzheimer disease.

Previous studies suggest the presence of increased concentrations of cerebral myo-inositol in Alzheimer disease (AD). To characterize this abnormality further, we quantified myo-inositol and several other polyols in cerebrospinal fluid (CSF) and plasma from 10 AD subjects and 10 healthy age-matched controls by using a gas chromatographic-mass spectrometric technique. The mean CSF concentration and CSF/plasma concentration ratio of myo-inositol in AD were not significantly different from those determined in control subjects. Also, concentration profiles of other polyols were not significantly altered in AD. CSF and plasma myo-inositol concentrations were correlated in control subjects but not in AD subjects. However, a significant correlation between CSF and plasma 1,5-anhydrosorbitol (a polyol internal control) concentrations observed in control subjects was retained in AD subjects.

Polyol profiles in Down syndrome. myo-Inositol, specifically, is elevated in the cerebrospinal fluid.

Polyols are reduction products of aldoses and ketoses; their concentrations in tissues can reflect carbohydrate metabolism. Several polyol species were quantitated in cerebrospinal fluid (CSF) and plasma from 10 Down Syndrome (trisomy 21) subjects between the ages of 22 and 63 years (3 of whom were demented) and from 10 healthy age-matched controls, using a gas chromatographic/mass spectrometric technique. The mean CSF concentration and the mean CSF/plasma concentration ratio of myo-inositol were significantly elevated in Down syndrome compared with controls, but were not correlated with the presence of dementia in the Down subjects. Plasma myo-inositol was not significantly altered in these subjects. No significant difference between Down syndrome and controls was found for CSF concentrations of mannitol, sorbitol, galactitol, ribitol, arabitol, or 1,5-anhydrosorbitol, but plasma mannitol, ribitol and arabitol were elevated in Down syndrome. The present observation provides new impetus for studying synthesis and transport of myo-inositol as well as phosphatidylinositol cycle in trisomy 21 disorder.

Capillary gas chromatography combined with ion trap detection for quantitative profiling of polyols in cerebrospinal fluid and plasma.

Polyol species in cerebrospinal fluid and plasma--ribitol, arabitol, xylitol, 1,5-anhydrosorbitol, myo-inositol, mannitol, sorbitol, and galactitol--simultaneously were quantitated by a capillary gas chromatography/ion trap (mass spectrometric) detection method. The details of the methodology are discussed and the results of analysis of polyols in healthy human subjects are reported. Microliter volumes of cerebrospinal fluid or plasma were mixed with internal standard (deuterium labeled myo-inositol), deproteinized, and evaporated to dryness. Polyols were acetylated in the presence of pyridine catalyst and washed with sodium bicarbonate solution and the acetate derivatives were recovered. Standard curve solutions were similarly treated. The polyol components were resolved on a capillary column bonded with 50% phenyl-50% methyl polysiloxane. Chemical ionization mass spectra for the acetate derivatives of polyols were generated in an ion trap using acetonitrile as reagent gas. Each polyol yielded a fragment ion in 100% abundance arising probably from the loss of one acetate moiety from the protonated molecule. These ions were monitored. The relative standard deviation (within-day) for quantitation of polyols was not greater than 8% for cerebrospinal fluid and 15% for plasma matrix. A polyol profile in cerebrospinal fluid and plasma was determined in healthy human subjects and a cerebrospinal fluid/plasma concentration ratio larger than 1.0 was found for all polyol species except 1,5-anhydrosorbitol and xylitol. This assay technique will be used to study the role of polyols in central nervous system diseases.

Arabinitol enantiomers in cerebrospinal fluid.

D-Arabinitol is a metabolite of Candida species, and its presence in serum above endogenous concentration may indicate disseminated candidiasis. The o-trifluoroacetylated derivatives of arabinitol enantiomers in cerebrospinal fluid (CSF) were separated using perpentylated cyclodextrin capillary columns and measured by selected ion monitoring using negative chemical ionization mass spectrometry. The presence of D-arabinitol was confirmed using highly specific D-arabinitol dehydrogenase. The mean D/L-arabinitol ratio, 16.7 +/- 4.8 (range: 8.6-22.8), in CSF of the "controls" is approximately 10-fold higher than the ratio previously found in normal serum and urine. At the same time, the mean L-arabinitol concentration, 0.13 +/- 0.05 (range: 0.09-0.2), is virtually identical to that in serum. Therefore, the high D/L-arabinitol ratio in CSF is attributed to D-arabinitol. Persistently high D/L ratios were found in a variety of diseases (without Candida infection). The finding of D-arabinitol in CSF suggests that serum D-arabinitol may originate from the brain or the spinal cord, rather than from resident Candida species in the gut, and that the accumulation of D-arabinitol in CSF may be caused by non-consumption or, conversely, the high concentration may be maintained in order to have it readily available for metabolism in the brain.

Serum levels of arabinitol in the detection of invasive candidiasis in animals and humans.

Arabinitol is a pentitol generated in large quantitites by several species of Candida, including Candida albicans. The level of arabinitol in the sera of infected animals and humans was determined by gas-liquid chromatography of an acetone extract of the serum. Experimentally infected mice with pyelonephritis due to C. albicans had elevated levels of arabinitol; rabbits with pyelonephritis did not have elevated levels, nor did rabbits with catheter-induce cystitis, but rabbits with endocarditis developed elevated levels of arabinitol shortly before death. A prospective study in patients clinically suspected of having invasive candidiasis failed to show elevated levels of arabinitol in most. Mice and patients not colonized or infected with yeasts but with renal failure had high serum levels of arabinitol. The data indicate that an elevated level of arabinitol in the serum of a patient without renal disease is suggestive of invasive candidiasis, but normal serum levels do not contradict the diagnosis.

Estimation of neutral sugars and sugar alcohols in biological fluids by gas-liquid chromatography.

Gas-liquid chromatographic procedures for measuring sugar and polyol concentrations in biological fluids are reviewed. Such methods require the preparations of derivatives such as methyl ethers, trimethylsilyl ethers or acetyl esters. Prior to derivatisation samples must be deproteinised and dried. Complex mixtures of sugars and sugar alcohols may be resolved. Quantitative analyses are precise, sensitive and linear. If internal standardisation is used recoveries approaching 100% are obtained.

Gas-chromatographic determination of polyol profiles in cerebrospinal fluid.

We describe a simple method for collectively determining polyols in the cerebrospinal fluid. The method consists of protein removal, sample derivatization, and gas chromatography of the trimethylsilylated polyols, with use of glass capillary columns. Nine major polyol constituents, the structures of which were verified by combined gas chromatography/mass spectrometry, can be simultaneously assayed. The presence of three polyols in the cerebrospinal fluid is reported here for the first time.

Gas chromatographic separation and mass spectrometric identification of polyols in human cerebrospinal fluid and plasma.

Seven polyols, erythritol, arabinitol, anhydroflucitol, mannitol, sorbitol, myoinositol and possibly ribitol were identified in human cerebrospinal fluid by means of gas-liquid chromatography and mass spectrometry. Quantitative data were obtained for five polyols, arabinitol, anhydroglucitol, mannitol, sorbitol and myoinositol, by screening of 205 CSF samples. These five polyols represented 90-95 per cent of the polyol-concentration which was 340 +/- 105 mumol/1 in the total series. The concentration of polyols in the CSF was two times higher than that in the plasma (148 +/- 30 mumol/1), where only anhydroglucitol and myoinositol could be quantitated. The variations noted were not associated with age, sex or the plasma concentrations of polyols. The polyols of the CSF most likely originate from brain tissue and/or spinal cord since penetration from the plasma against a gradient seems unlikely.

Polyols in the cerebrospinal fluid and plasma of neurological, diabetic and uraemic patients.

Five polyols, arabinitol, anhydroglucitol, mannitol, sorbitol and myoinositol, normally present in the cerebrospinal fluid (CSF), were studied. Quantitative gas-liquid chromatographic analysis of 211 CSF and 112 plasma samples indicated significantly altered concentrations in several clinical conditions. All five polyols were decreased in the CSF of patients suffering from meningitis, cerebral atrophy, sepsis, and in patients receiving intrathecal cytostate therapy. Equilibration between plasma and CSF may explain the changes in sepsis and meningitis, while decreased total number of functioning cells may cause the decrease in cerebral atrophy. Intrathecal cytostates seem to have a destroying effect on the cell metabolism of the central nervous system. Renal failure causes accumulation of polyols in the plasma. Alterations in the metabolism of sorbitol, myoinositol and anhydroglucitol seem to be present in diabetes. The plasma concentration of anhydroglucitol is decreased in renal failure.

Variation in polyol levels in cerebrospinal fluid and serum in diabetic patients.

Cerebrospinal fluid (CSF) or CSF and plasma levels of sorbitol, 1,5-anhydroglucitol and myoinositol of diabetic and non-diabetic patients with normal kidney function and of diabetic and non-diabetic patients with impaired kidney function were measured by gas-liquid chromatography. The CSF sorbitol level correlated with the plasma glucose level (p less than or equal to 0.05) in diabetic patients with normal kidney function, having received insulin for less than 12 months. The correlation between CSF sorbitol and plasma glucose levels in patients not dependent on insulin was not significant. Sorbitol was not detected in the plasma. The highest sorbitol levels in CSF were seen in insulin-dependent diabetic patients with impaired kidney function. No rise was seen in non-diabetic uremia. 1,5-anhydroglucitol, normally present in plasma, was absent from CSF and plasma in diabetic patients receiving insulin. In non-diabetic uremic patients, 1,5-anhydroglucitol levels in CSF and plasma were lower than in healthy subjects, but htere was no correlation with plasma glucose levels. The myoinositol level was higher in CSF than in the plasma of both non-diabetic and diabetic patients with normal kidney function. Both plasma and CSF levels were significantly (p less than 0.001) elevated in diabetic as well as in non-diabetic uremic patients, the plasma myoinositol increasing relatively more than the CSF levels. The elevation of plasma myoinositol correlated with the elevation of plasma creatinine and thus also with the impairment of kidney function. Plasma and CSF myoinositol levels were not influenced by the plasma glucose level.