Corrected Fructosamine improves both correlation with HbA1C and diagnostic performance.

AIMS: There is increasing interest in using fructosamine measurements in screening for or managing diabetes, yet uncertainty remains as to whether these measurements should be corrected for variation in serum protein concentrations. METHODS: We considered all sets of simultaneous measurements of fructosamine, albumin, total serum protein (TP), fasting plasma glucose (FPG) and HbA1C recorded in our laboratory over 10years. The relationships between fructosamine and other variables were studied by multivariate linear regression and other analyses, and receiver operating curves (ROCs) were analysed to compare the diabetes screening performance of uncorrected fructosamine to those of albumin-corrected fructosamine (FAAlb) and TP-corrected fructosamine (FATP). RESULTS: 40,938 sets of measurements were collected from 20,114 patients. Though correlation between fructosamine and serum proteins was strongest among patients with HbA1C <6.5% (48mmol/mol), it was also significant in the whole sample (r=0.193 for albumin, r=0.213 for TP). With diabetes defined by HbA1C ≥6.5% (48mmol/mol), the areas under the ROCs of FAAlb (0.905) and FATP (0.895) were both significantly greater (P<0.001) than that of uncorrected fructosamine (0.878). Correction of fructosamine for albumin or TP slightly improved its correlation with HbA1C. There was no correlation of protein (albumin or TP) with log(fructosamine/protein). CONCLUSIONS: Fructosamine concentration correlates significantly with albumin and total protein concentrations throughout their ranges. Correction of fructosamine improves its correlation with HbA1C and its performance in detecting diabetes.

Intrapersonal HbA(1c) variability and the risk of progression of nephropathy in patients with Type 2 diabetes.

AIM: To investigate the association between nephropathy and HbA(1c) variability (assessed as the standard deviation of each patient's HbA(1c) measurements) among patients with Type 2 diabetes. METHODS: Albumin excretion rate and HbA(1c) were measured in 2103 patients followed up for a mean 6.6 years. Multivariate Cox regression analysis was used to determine the influence of HbA(1c) variability on the risk of progression of nephropathy after adjustment for age, sex, duration of diabetes, baseline condition (two cohorts defined by duration of diabetes, retinopathy and albumin excretion rate), baseline HbA(1c) , insulin use, BMI, use of anti-hypertensive agents, smoking, lipid status, retinopathy, updated mean HbA(1c) and number of HbA(1c) measurements. RESULTS: Nephropathy progressed in 18.3% of subjects. HbA(1c) variability was significantly greater among progressors than among non-progressors (12 vs. 10 mmol/mol; 1.12 vs. 0.90%; P < 0.0001) and was a significant predictor of progression of nephropathy even after adjustment for updated mean HbA(1c) and other risk factors (hazard ratio 1.37, 95% CI 1.12-1.69). CONCLUSION: In patients with Type 2 diabetes, the risk of progression of nephropathy increases significantly with HbA(1c) variability, independently of the influence of updated mean HbA(1c) .

Therapeutic criteria in communicating childhood hydrocephalus.

AIM: The aim of this study was to evaluate the usefulness of cerebral blood flow velocity in the middle cerebral artery measured by transcranial Doppler as criteria to therapeutic action in communicating hydrocephalic children. METHODS: In eight non-tumoral communicating hydrocephalic infants, ranging from five to 18 months of age, monitored from 18 to 36 months (mean time of follow-up: 24.25 months), cerebrospinal fluid (CSF) oxypurines (hypoxanthine and xanthine) and uric acid levels were compared by means of the Evans' index, the mean weekly increase in cranial circumference, and the transcranial Doppler measurements. RESULTS: Results indicate that clinical (mean weekly increase in head circumference), radiological (Evans' index), biochemical (oxypurines and uric acid in the CSF), and hemodynamic (transcranial Doppler) criteria have the same role in monitoring infantile hydrocephalus. CONCLUSION: In conclusion the transcranial Doppler measurement can be done noninvasively and examinations can be repeated when needed, obtaining immediate RESULTS: Hence, it is the most adequate monitoring technique in clinical practice.

Concentrations of nucleotides, nucleosides, purine bases, oxypurines, uric acid, and neuron-specific enolase in the cerebrospinal fluid of children with sepsis.

To determine the effects of sepsis on cerebral energy metabolism, the cerebrospinal fluid adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, hypoxanthine, xanthine, and urate concentrations were determined by high-performance liquid chromatography and the neuron-specific enolase levels by means of an enzyme immunoassay method in 32 children with sepsis, without meningitis, aged between 2 months and 13 years, and in 160 age-matched controls. The septic group had significantly higher cerebrospinal fluid concentrations of inosine, adenosine, xanthine, and urate than controls. These results suggest that sepsis could provoke some degree of neuronal hypoxia and significant alterations of cerebral energy metabolism homeostasis.

Cerebrospinal fluid purine metabolite and neuron-specific enolase concentrations after febrile seizures.

If febrile seizures cause significant compromise of neuronal metabolism (whether permanent or reversible), this should be reflected in an increase in the cerebrospinal fluid concentrations of neuron-specific enolase (NSE) and/or adenosine triphosphate (ATP) breakdown products. In the present study, AMP, IMP, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine, uric acid and NSE concentrations were determined in the cerebrospinal fluid of 90 children 1 h after febrile seizure (73 simple febrile seizures (SFS); 17 complex febrile seizures (CFS)), and in a control group of 160 children. There was no statistically significant difference between the SFS group and the control group for any of the substances determined, suggesting that SFS neither significantly depletes neuronal ATP concentration, nor significantly increases NSE concentration; thus, SFS do not appear to constitute a threat to neuronal integrity. However, patients with CFS showed significantly lower IMP concentrations and significantly higher adenine concentrations than controls, and significantly higher AMP concentrations than SFS patients; these results suggest that CFS may affect energy metabolism in the brain. However, NSE concentrations were normal in the cerebrospinal fluid of both SFS and CFS patients, suggesting that neither type of seizure causes significant neuronal damage, at least early after the seizure.

Ghrelin-induced growth hormone secretion in humans.

Ghrelin is a novel growth hormone (GH) releaser acylated peptide that has recently been purified from stomach, and which potently binds to the GH secretagogue receptor. Ghrelin releases GH in vitro and in vivo in animal models, however its actions, potency and specificity in humans are unknown. In the present study, 12 healthy subjects were studied: 6 underwent four tests with ghrelin administered i.v. at the dose of 0 (placebo), 0.25, 0.5 and 1 microg/kg which corresponds to 0, 18, 37 and 75 microg total dose. A further 6 volunteers underwent two tests on different days with ghrelin at the dose of 3.3 or 6.6 microg/kg which corresponds to 250 microg and 500 microg total dose. Ghrelin-mediated GH secretion showed a dose-response curve, in which 1 microg/kg was the minimally effective dose in some individuals, but not as a group. On the contrary, the total doses of 250 microg and 500 microg elicited a powerful GH secretion, with a mean peak of 69.8+/-9.2 microg/l and 90.9+/-16.9 microg/l respectively, and areas under the curve of 4435+/-608 and 6125+/-1008 microg/l per 120 min respectively. All of them statistically significant vs placebo and vs the 1 microg/kg dose. Ghrelin administration also elicited a relevant dose-response mediated prolactin secretion suggesting no specificity of its actions. No relevant side effects were observed with ghrelin apart from a hyperhydrosis episode in two individuals tested with the higher ghrelin doses. In conclusion, ghrelin is a potent releaser of GH in normal individuals, with a dose-response pattern of operation. No saturating dose was observed.

Neuron-specific enolase levels in the cerebrospinal fluid of neurologically healthy children.

Levels of neuron-specific enolase (NSE) levels in the cerebrospinal fluid (CSF) of children without neurological disease were assessed. CSF samples were obtained from 37 subjects aged between 1 month and 13 years. All subjects had undergone lumbar puncture for diagnostic purposes, and were subsequently shown not to be suffering any form of neurological disease. NSE levels in CSF were determined by an enzyme immunoassay method. NSE level ranged from below the detection limit to 4.8 ng/ml (1.52+/-1.01 ng/ml). The present results may be useful as a basis for defining reference levels of NSE in CSF in post-neonatal children.

Serum carnitine levels in epileptic children before and during treatment with valproic acid, carbamazepine, and phenobarbital.

Serum levels of free, acyl, and total carnitine were determined in 32 patients with seizures, before and after 3, 6, and 12 months of treatment with valproic acid (17 patients), carbamazepine (10 patients), or phenobarbital (5 patients). In all three treated groups, both free and total carnitine levels showed a significant decline with respect to pretreatment levels. This decline was most marked and most consistent in patients treated with valproic acid. In 35% of the patients in this group, carnitine deficiency (ie, total carnitine < 30 micromol/L) was observed by month 12. In none of the three groups were serum carnitine levels significantly correlated with the serum concentration of the drug. These findings suggest a need to monitor serum carnitine levels in children treated with any of these drugs.

Acute changes in free-fatty acids (FFA) do not alter serum leptin levels.

Leptin, the product of the ob gene, is a recently discovered hormone secreted by adipocytes. Serum leptin concentrations increase in correlation with the percentage of body fat, but besides that little is known about the physiological actions of leptin in humans. The aim of this study was to assess the influence of changes in circulating free-fatty acids on serum leptin levels. Increases in plasma FFA levels (p < 0.02) were obtained in a group of normal subjects following the administration of intralipid plus heparin (250 ml 10% Intralipid plus 5000 U heparin). FFA reduction was achieved through the administration of acipimox (250 mg, orally, at 0 min and at 210 min), a lipid-lowering drug devoid of side effects, to a group of normal (p < 0.02) and obese subjects (p < 0.05). An increase in circulating FFA levels in normal subjects (n = 6), following administration of a lipid-heparin infusion, failed to modify plasma leptin levels as assessed by the area under the curve (AUC; mean +/- SE 892 +/- 168 for placebo vs 896 +/- 260 following intralipid plus heparin). Similarly, whereas acipimox pretreatment induced a reduction in FFA levels compared to placebo in normal (n = 6) and obese subjects (n = 8), it also failed to modify plasma leptin levels at any time-point studied. The results indicate that short-term reduction or increase in circulating FFA are not associated to changes in plasma leptin levels.

[3-hydroxy-3-methylglutaric aciduria and recurrent Reye-like syndrome]. / Aciduria 3-hidroxi-3-metilglutárica y síndrome Reye-like recurrente.

INTRODUCTION: 3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (HMG-CoA lyase) is an inborn error of ketogenesis and Leucine catabolism. HMG-CoA lyase catalyses the final step in leucine degradation, converting HMG-CoA to acetyl-CoA and acetoacetic acid. Clinical manifestations include hepatomegaly, lethargy or coma and apnoea. Biochemically there is a characteristic absence of ketosis with hypoglycemia, acidosis, hipertransaminasemia and variable hyperammoniemia. The urinary organic acid profile includes elevated concentrations of 3-hydroxy-3-isovaleric, 3-hydroxy-3-methylglutaric, 3-methylglutaconic and 3-methylglutaric acids. CLINICAL CASE: Here, we report the case of a 17-year-old girl who presented in both ten months and five years of age a clinical picture characterized by lethargy leading to apnea and coma, hepatomegaly, hypoglycemia, metabolic acidosis, hyperammoniemia, elevated serum transaminases and absence of ketonuria. Diagnostic of Reye syndrome was suggested by hystopathologic finding of hepatic steatosis and clinical and biochemical data. As of 11 years old, laboratory investigations revealed carnitine deficiency and characteristic aciduria. Confirmatory enzyme diagnosis revealing deficiency of HMG-CoA lyase was made in cultured fibroblasts. CONCLUSION: Our report constitutes an example of the presentation of HMG-CoA lyase deficiency as recurrent Reye-like syndrome.

Increased concentrations of serum pentosidine in rheumatoid arthritis.

Advanced glycosylation end products (AGEs) are thought to play an important role in the development of diabetic complications. Oxidative reactions are essential for the formation of some AGEs, termed glycoxidation products. Increased concentrations of pentosidine, one of such products, are found in tissue and serum in diabetes mellitus and in end-stage renal disease, suggesting that hyperglycemia and impaired renal function are important factors in AGE accumulation. We hypothesized that increased concentrations of pentosidine would also be found in pathological conditions associated with increased oxidative stress. We measured pentosidine in sera of patients with rheumatoid arthritis (RA), systemic lupus erythematosus, and diabetes. Increased serum pentosidine was found in RA (108.4 +/- 146.5 nmol/L, P < 0.002) and in diabetes (69.6 +/- 42.4 nmol/L, P < 0.001) as compared with healthy subjects (48.3 +/- 12.0 nmol/L). These results prove that AGEs may accumulate in the absence of hyperglycemia or impaired kidney function.

A two-base deletion in exon 6 of the 3-hydroxy-3-methylglutaryl coenzyme A lyase (HL) gene producing the skipping of exons 5 and 6 determines 3-hydroxy-3-methylglutaric aciduria.

A novel two-base deletion in the 3-hydroxy-3-methylglutaryl coenzyme A lyase (HL) gene was found in a Spanish patient with homozygous 3-hydroxy-3-methylglutaric aciduria. Amplification by RT-PCR of the mRNAs showed that the gene was transcribed into three different mRNAs. One showed the complete deletion of exons 5 and 6 located between nucleotides 348 and 561 of the HL cDNA. The second transcript showed deletion of exon 6 only, and the third contained a two-base deletion CT in exon 6, corresponding to nucleotides 504 and 505 of the HL cDNA. These aberrant mRNAs are predicted to encode three abnormal HMG-CoA lyase proteins; the first (from skipped exons 5 and 6) lacks 71 amino acids, which represents 24% of the mature protein; the second, (from the skipping of exon 6, producing a frameshift) contains only 192 amino acids, the last 26 of which are missense amino acids preceding a stop codon; the third contains only 175 amino acids, the last 7 of which are missense. Northern blot analysis showed that the HL mRNA levels of the patient were 4% of the control. PCR quantitative analysis indicated that the mRNA lacking exons 5 and 6 was the most abundant, representing 88% of the total. The other two mRNAs represented 8% and 4%, respectively. In the genomic DNA only one CT deletion was found at positions +7 and +8 at beginning of exon 6. No mutations were observed in the splice donor, splice acceptor, or pyrimidine-rich sequences of the intronic regions flanking exons 5 and 6. All three aberrant mRNAs resulted only from the deletion of nucleotides CT. We suggest that this deletion may affect the interaction between the small nuclear ribonucleoproteins (snRNPs) and exon 6, and that, as a result, the abnormal splicing of the pre-mRNA produces two different aberrant transcripts.

High serum IgA concentrations in patients with diabetes mellitus: agewise distribution and relation to chronic complications.

In this study we investigated the agewise distributions of serum IgA concentrations in 1251 type 1 and 2224 type 2 diabetic patients, and the association between serum IgA concentration and diabetic complications (retinopathy, neuropathy, nephropathy, macroangiopathy, and hypertension). The IgA concentrations of all groups of diabetic patients were significantly higher than those of the corresponding subgroups of 943 control subjects, except for type 1 patients >60 years of age. High IgA concentrations were found in 23.1% of the whole diabetic group. The prevalence of high IgA was significantly greater in males than in females among type 1 patients (24.4% vs 18%). In conclusion, an increase in circulating IgA concentrations is a generalized phenomenon among diabetic patients; IgA concentrations above the reference range are more common among male than female diabetics; and diabetic complications are associated with a significant increase in serum IgA concentration.

Cerebrospinal fluid purine metabolites after complex febrile convulsions.

Adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine and uric acid were determined in cerebrospinal fluid (CSF) of 15 children after complex febrile seizures (CFS) and in 27 after simple febrile seizures (SFS), and compared with those in a control group of 63 children. There was no statistically significant difference between the groups for any of these metabolites, suggesting that CFS and SFS neither significantly disturb the metabolism of nucleotides, nucleosides or bases nor significantly deplete neuron adenosine triphosphate levels.

Purine and carnitine metabolism in muscle of patients with Duchenne muscular dystrophy.

We determined levels of purines, purine metabolites, related enzymes and carnitine in muscle of 8 untreated Duchenne muscular dystrophy (DMD) patients, 12 allopurinol-treated DMD patients and 12 age-matched controls. Muscle of DMD patients was found to be deficient in ATP, ADP, adenylsuccinate, hypoxanthine, guanine and adenylsuccinate synthetase. In allopurinol-treated DMD patients, mean total adenylate level was only three times less than in controls (versus 14 times less in untreated DMD patients). Mean inosine monophosphate (IMP), adenine, adenosine, inosine, xanthine, guanine, guanosine and uric acid levels were higher in allopurinol-treated patients than in controls, while mean adenylsuccinate levels were higher than in untreated patients. Allopurinol also restored acylcarnitine levels to normal and significantly increased free carnitine levels. These findings strongly support the hypothesis that Duchenne muscular dystrophy involves alterations leading to blockage of the IMP-->purine pathway and that allopurinol treatment favours restoration of purine levels by this route. Furthermore, our results suggest that the observed deficiencies in cell components unrelated to purine metabolism are long-term secondary effects.

Cerebrospinal fluid purine metabolites and pyrimidine bases after brief febrile convulsions.

Adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine, uric acid, and pyrimidines bases were determined in cerebrospinal fluid (CSF) of 52 children after simple febrile seizures and in a control group of 63 children. There was no statistically significant difference between the two groups for any of these metabolites, suggesting that simple febrile seizures (SFS) neither significantly disturb the metabolism of nucleotides, nucleosides, or bases nor significantly deplete neuron adenosine ATP levels. Therefore, they do not appear to constitute a threat of neuronal damage.

Concentrations of nucleotides, nucleosides, purine bases and urate in cerebrospinal fluid of children with meningitis.

The release of agents mediating inflammation in meningitis may bring about neuronal hypoxia, under which circumstances ATP concentrations decrease and its degradation products increase and are released into the cerebrospinal fluid. In this study of alterations in neuronal energy metabolism in meningitis, AMP, IMP, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine and urate were determined by high performance liquid chromatography in the cerebrospinal fluid of 54 children aged between 1 month and 13 years suffering from meningitis (25 viral, 24 bacterial and 5 tuberculous cases) and 63 controls. Compared to the controls, patients with viral meningitis exhibited high concentrations of IMP, adenosine, guanosine, adenine, guanine and xanthine; patients with bacterial meningitis exhibited high concentrations of IMP, inosine, guanosine, adenosine, hypoxanthine, xanthine and urate; and patients with tuberculous meningitis exhibited high concentrations of AMP, guanosine, xanthine and urate. Viral and bacterial cases did not differ significantly for any of the metabolites studied. AMP and urate concentrations were significantly higher in patients with tuberculous cases compared with viral or bacterial meningitis cases.

Indicators of hypoxia in cerebrospinal fluid of hydrocephalic children with suspected shunt malfunction.

We used high performance liquid chromatography to determine the concentration of purine metabolites in the cerebrospinal fluid of three hydrocephalic children with a history of shunt malfunction. Hypoxanthine and xanthine levels were high in comparison with controls. We consider these purines to be valuable indicators of disturbance of neuronal metabolism following the sustained rise in intracranial pressure caused by shunt valve malfunction.

Concentrations of purine nucleotides and purine and pyrimidine bases in cerebrospinal fluid of neurologically healthy children.

The concentrations of the nucleotides AMP and IMP, the nucleosides adenosine, guanosine and inosine, the purine bases adenine, guanine, hypoxanthine and xanthine, urate, and the pyrimidine bases cytosine, thymine and uracil were determined by high performance liquid chromatography in the cerebrospinal fluid of 63 children aged between 1 month and 13 years who showed no sign of neurological disease. The results are compared with those of other authors, and used to establish reference ranges for the above metabolites in the cerebrospinal fluid of children.