Urinary proteome signature of Renal Cysts and Diabetes syndrome in children.

Renal Cysts and Diabetes Syndrome (RCAD) is an autosomal dominant disorder caused by mutations in the HNF1B gene encoding for the transcriptional factor hepatocyte nuclear factor-1B. RCAD is characterized as a multi-organ disease, with a broad spectrum of symptoms including kidney abnormalities (renal cysts, renal hypodysplasia, single kidney, horseshoe kidneys, hydronephrosis), early-onset diabetes mellitus, abnormal liver function, pancreatic hypoplasia and genital tract malformations. In the present study, using capillary electrophoresis coupled to mass spectrometry (CE-MS), we investigated the urinary proteome of a pediatric cohort of RCAD patients and different controls to identify peptide biomarkers and obtain further insights into the pathophysiology of this disorder. As a result, 146 peptides were found to be associated with RCAD in 22 pediatric patients when compared to 22 healthy age-matched controls. A classifier based on these peptides was generated and further tested on an independent cohort, clearly discriminating RCAD patients from different groups of controls. This study demonstrates that the urinary proteome of pediatric RCAD patients differs from autosomal dominant polycystic kidney disease (PKD1, PKD2), congenital nephrotic syndrome (NPHS1, NPHS2, NPHS4, NPHS9) as well as from chronic kidney disease conditions, suggesting differences between the pathophysiology behind these disorders.

Silent increase of urinary ethylmalonic acid is an indicator of nonspecific brain dysfunction.

Our aim was to compare urinary ethylmalonic acid (EMA) levels in subjects who had no apparent clinical reason to have increased levels of this substance but were suffering from non-specific CNS impairment, and healthy controls. Urinary EMA concentrations detected by (1)H-NMR spectroscopy were studied in 130 subjects with CNS impairment of unknown origin (with no definite diagnosis, no specific symptoms or signs, and normal common biochemical and metabolic screening results) and 130 age- and sex-matched healthy subjects. EMA levels exceeding two standard deviations (SD) above normal (i.e. 8.1 mmol/molCn) were found in a subgroup of CNS-impaired patients and healthy controls. EMA levels exceeding 2 SD above normal were fourfold prevalent in the urine of patients with non-specific CNS impairment compared to from the EMA levels in healthy controls. Moreover, we found that the level exceeding > 8.1 mmol/molCn (i.e. > + 2 SD) had sufficient discrimination accuracy in identifying subjects with non-specific CNS impairment; the level exceeding 12 mmol/molCn (i.e. > + 6 SD) reaches suitable accuracy (i.e. 100% specificity and 78.6% sensitivity). These observations are of importance, as we found that subtle increases in urinary EMA levels are frequent in patients with non-specific CNS impairment. The reasons for this association remain unknown.

AT1 receptors mediate chronic central nervous system AII hypertension in rats fed high sodium chloride diet from weaning.

CNS angiotensin II (AII) hypertension is induced by chronic, low dose intracerebroventricular (ICV) AII infusion only in rats raised on a relatively high sodium chloride diet (250 meq kg(-1)food) from weaning. This experimental model of hypertension is dependent upon renal sympathetic innervation and associated with neurogenic sodium retention. This study determined whether AT1 and/or AT2 receptor subtypes in the CNS mediate this neurogenic ICV AII hypertension. Rats were weaned at 21 days of age and fed a 1.5% sodium chloride diet for 10-12 weeks. At adulthood, animals were instrumented with CNS lateral ventricular cannulas, femoral arterial and vein catheters and housed in metabolic pens for chronic study. Low dose ICV AII infusion (20 ng min(-1) )increased mean arterial pressure by 12+/-2 mm Hg and decreased urinary sodium excretion for three consecutive days. Subsequent ICV AT1 blockade with losartan abolished both the pressor and antinatriuretic responses to low dose ICV AII. In contrast, ICV AT2 receptor blockade with PD 123319 did not affect either angiotensin induced pressor or antinatriuretic responses. Following cessation of ICV AII infusion, arterial pressure and sodium excretion returned to values not significantly different from control in both groups of rats. These data confirm that low dose ICV AII causes hypertension and sodium retention in rats raised from early age on moderately elevated sodium intakes. This AII mediated neurogenic hypertension and antinatriuresis is transduced by activation of CNS AT1 receptors and not by activation of central AT2 receptors.

Central nervous system hemangiomatosis in early childhood.

Two cases of hemangiomatosis are reported, a girl of 3 years of age and a boy 2 years of age, both with central nervous system (CNS) involvement. In the first, the CNS lesions were asymptomatic; in the second, symptomatic. Magnetic resonance imaging was used both to identify the lesions and to follow their evolutions. In the first case, the CNS lesions involuted in parallel with those in skin and liver. In the second, while there was no obvious resolution of the CNS lesions, there was a decrease in the level of urine basic fibroblast growth factor, indicating the lesions were probably involuting. Serial magnetic resonance imaging studies and urine assays of basic fibroblastic growth factor have important roles to play in following CNS involvement in hemangiomatosis.

Urinary homovanillic acid and vanillylmandelic acid in workers exposed to carbon disulfide.

Homovanillic acid (HVA) and vanillylmandelic acid (VMA), two end products of dopamine metabolism, were measured in 60 workers exposed to carbon disulfide (CS(2)) in a rayon factory and in 48 unexposed workers. The airborne CS(2) concentrations in eight major exposure zones of the plant were measured monthly over a period of 4 years, from 1990 to 1994. In addition, the exposure concentrations and exposure history of each worker were integrated to estimate the overall lifetime exposure. Industrial hygiene data showed that the geometric mean concentrations of CS(2) in the plant ranged from 2.68 to 20.19 ppm, and more than 15% of the studied population had been repeatedly exposed to CS(2) at concentrations exceeding the ACGIH recommended time-weighted average of 10 ppm. The results showed that there was a significantly lower level and a higher proportion of CS(2) workers with decreased HVA and VMA excretion. However, there were no statistical correlations between the two dopaminergic metabolites and the mean CS(2) concentration, and years of employment. In contrast, significant dose-effect relationships were observed between these two metabolites and the integrated cumulative exposure (ICE) variable. The correlation coefficients for ICE and HVA, and ICE and VMA were -0.35 (p < 0.01) and -0.20 (p <0.05), respectively. These data suggest that chronic exposure to CS(2) was associated with measurable reduction in catecholamine metabolite concentrations. This finding is compatible with the earlier observations in laboratory animals that CS(2) exposures interfere with neurochemical metabolism.

Altered porphyrin metabolism as a biomarker of mercury exposure and toxicity.

Changes in urinary porphyrin excretion patterns (porphyrin profiles) have been described in response to a variety of drugs and chemicals. The present studies were conducted to define the specific changes in the urinary porphyrin profile associated with prolonged exposure to mercury and mercury compounds. In rats, exposure for a prolonged period to mercury as methyl mercury hydroxide was associated with urinary porphyrin changes, which were uniquely characterized by highly elevated levels of 4- and 5-carboxyl porphyrins and by the expression of an atypical porphyrin ("precoproporphyrin") not found in urine of unexposed animals. These distinct changes in urinary porphyrin concentrations were observed as early as 1-2 weeks after initiation of mercury exposure, and increased in a dose- and time-related fashion with the concentration of mercury in the kidney, a principal target organ of mercury compounds. Following cessation of mercury exposure, urinary porphyrin concentrations reverted to normal levels, consistent with renal mercury clearance. In human studies, a comparable change in the urinary porphyrin profile was observed among subjects with occupational exposure to mercury as mercury vapor sufficient to elicit urinary mercury levels greater than 20 micrograms/L. Urinary porphyrin profiles were also shown to correlate significantly with mercury body burden and with specific neurobehavioral deficits associated with low level mercury exposure. These findings support the utility of urinary porphyrin profiles as a useful biomarker of mercury exposure and potential health effects in human subjects.

Central nervous system demyelinating diseases and increased release of cholesterol into the urinary system of rats.

The question of what happens to cholesterol in the adult central nervous system during its slow turnover has been addressed using rats with brain and spinal cord labeled with [4-14C]cholesterol upon intracerebral injection of labeled cholesterol into rats at 10-12 days of age. At six months after injection, 14C was found only in the brain and spinal cord and was slowly released via the rat's urine. When labeled rats were given demyelinating agents (triethyl tin chloride, hexachlorophene, sodium cyanide) and when experimental allergic encephalomyelitis was induced, a measurable increase in urinary 14C label above control levels was found. It was concluded that there is a direct relationship between the experimental demyelination induced and the increased release of cholesterol metabolites into urine. The study suggests that a clinical method could be developed to determine the rate of central nervous system demyelination by measuring the amount of urinary cholesterol metabolites.

[Toxic melanoderma in chronic intoxication with trinitrotoluene]. / Toksicheskaia melanodermiia pri khronicheskoi intoksikatsii trinitrotoluolom.

Hyperkinetic atactic syndrome, an atypical neurologic disorder of a chemical origin, was reported in connection with trinitrotoluene-induced melanoderma. Decreased level of urinary 17-hydroxycorticoids stresses the failure of one biochemical link in melanin synthesis, but proves the same pathogenic origin of both melanopathy manifestations. Antioxidant therapy in the pathogenesis treatment of melanoderma is considered valuable.

Quantification of N-acetyl-L-aspartic acid in urine by isotope dilution gas chromatography-mass spectrometry.

A method for quantification of N-acetyl-L-aspartic acid by isotope dilution gas chromatography-mass spectrometry using 15N-[2H3]acetyl-L-aspartic acid is described. The method is sufficiently sensitive to be used with solvent extraction techniques commonly employed for urinary organic acid analysis. The mean concentration of N-acetyl-L-aspartic acid in 80 normal and abnormal control urine specimens was 19.7 +/- 10.8 mg/g creatinine (12.7 +/- 7.8 mmol/mol creatinine). Seven patients, ages 9 months to 7 years, with Canavan-van Bogaert syndrome had urinary N-acetyl-L-aspartic acid levels from 606 to 4760 mg/g creatinine. The method can also be used with cerebrospinal fluid, in which the concentration of N-acetyl-L-aspartic acid is about one-tenth of that in urine.

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.

Symmetrical necrosis of the basal ganglia in methylmalonic acidaemia.

In a patient with methylmalonic acidaemia (MMAA), persistent neurological symptoms were observed in addition to the acute episodes of metabolic dysequilibrium. CT scan and magnetic resonance imaging revealed bilateral symmetrical necrosis of the globus pallidus. Different episodes of metabolic decompensation, one with severe acidosis, had occurred. Persistent neurological symptoms in patients with MMAA who are appropriately treated suggest irreversible brain damage which appears to occur preferentially at the level of the basal ganglia.

Intrapartum hypoxia: the association between neurological assessment of damage and abnormal excretion of ATP metabolites.

A series of 29 newborn infants had been studied after intrapartum hypoxia defined as meconium aspiration, an Apgar score of less than or equal to 6 at 5 min or a peripheral blood pH of 7.2 or less after resuscitation. Two independent sets of techniques were used; one concerned with the critical system in hypoxic damage, the central nervous system, the other assessing the central biochemical events in hypoxia. Both sets of data were assembled, then graded separately and only then combined. In this way detailed neurological assessment has been combined with measurement of urinary excretion of the ATP metabolites, hypoxanthine and xanthine. The essential metabolic consequence of hypoxia is a reduction in the synthesis of the energy currency of cells, ATP. This is associated with an outflow of ATP metabolites from cells. The extent of neurological damage was related to the magnitude of the hypoxanthine and xanthine excretion; neither were closely related to the initial blood pH. Infants who were normal neurologically had normal oxypurine excretion. Infants with neurological abnormalities for less than 48 h had lower excretion than those who were abnormal for more than 48 h. The duration of abnormal oxypurine excretion after an acute episode of hypoxia was studied in two infants with respiratory distress and in two other infants with apnoeic attacks. Severe hypoxia was followed by abnormal oxypurine excretion for at least 40 h after an acute episode. It is justifiable to suggest that abnormalities of oxypurine excretion should indicate intrapartum hypoxia in newborn infants. This excretion should also quantify the metabolic damage.

Shy-Drager syndrome with abnormal respirations and antidiuretic hormone release.

A patient with Shy-Drager syndrome exhibited a partial defect in antidiuretic hormone (ADH) release, and cluster breathing, an indication of pontomedullary respiratory center damage, with a normal CO2 response curve. This extends the spectrum of abnormalities associated with the degenerative disease of the central nervous system. The presence of a pontomedullary respiratory pattern without an impaired CO2 response curve suggests that neurons that determine respiratory rhythm function independently from those that function as chemoreceptors.