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Biomedical subjects

M Duran

Publications and source records attributed to M Duran.

At least 19 recordsLinked to original sources
PubMed1996

3-, 6- and 7-hydroxyoctanoic acids are metabolites of medium-chain triglycerides and excreted in urine as glucuronides.

Three new metabolites of medium-chain fatty acid oxidation, 3-, 6- and 7-hydroxyoctanoyl beta-D-glucuronide, were identified in the urine of six infants who were fed a diet enriched in medium-chain triglycerides (MCT). Glucuronides were extracted from the urine by organic solvent extraction with ethyl acetate and by solid-phase extraction on Sep-Pak C18 cartridges. The compounds of interest were also purified from the organic solvent extract by preparative one-dimensional thin-layer chromatography. Cleavage of the glucuronides was achieved by either alkaline hydrolysis or enzymatic hydrolysis with beta-D-glucuronidase. The analyses of the trimethylsilylated derivatives were performed both by gas chromatography with flame ionization detection (GC/FID) and by gas chromatography/mass spectrometry (GC/MS). The structure of the hydroxyoctanoic acids was proved by comparison of their mass spectra with those of reference substances. Authentic 6-hydroxyoctanoic acid was synthesized. The presence of 6-hydroxyoctanoyl glucuronide shows that in addition to beta-oxidation, omega-oxidation and (omega-1)-hydroxylation, medium-chain fatty acids can be oxidized at the omega-2 position. The conjugation of medium-chain hydroxy-monocarboxylic acids with glucuronic acid has not been described in humans before.

Caprylates↗
PubMed1996

Amniotic fluid odd-chain fatty acids are increased in propionic acidaemia.

Odd-chain (C15 and C17) fatty acids have been reported to accumulate in tissues and body fluids of patients with propionic and methylmalonic acidaemia. We investigated the occurrence of these substances in amniotic fluid samples. The odd-chain fatty acid levels (expressed as the percentage of total C12-C20 fatty acids) in eight control samples ranged from 3.7 to 12.5 per cent. Three samples from affected propionic acidaemia pregnancies had values of 15.3-22.9 per cent; one methylmalonic acidaemia sample had a normal level of 9.3 per cent. These results supply further evidence of the prenatal accumulation of odd-chain fatty acids in propionic acidaemia.

Amino Acid Metabolism, Inborn Errors↗
PubMed1996

Tetrahydrobiopterin loading test in xanthine dehydrogenase and molybdenum cofactor deficiencies.

The objectives of this study were to find additional diagnostic information for the evaluation of xanthine dehydrogenase deficiency and molybdenum cofactor deficiency. Patients were given an oral loading test with 10 mg/kg 5,6,7,8-tetrahydrobiopterin. Urine excretion of pterin and isoxanthopterin was measured by HPLC. Control subjects had a fairly constant ratio of urinary pterin/isoxanthopterin before (0.57-5.32) and after (0.55-4.55) 5,6,7,8-tetrahydrobiopterin loading. These ratios were increased to 33 and 22 in a patient with hereditary xanthinuria and to 570 and 8030 in a patient with molybdenum cofactor deficiency. Obligate heterozygotes had an entirely normal test result. Evidence was obtained for the in vivo involvement of xanthine dehydrogenase in the conversion of pterin to isoxanthopterin. This test could be a sensitive marker for the establishment of residual enzyme activity.

Administration, Oral↗
PubMed1996

Congenital non-progressive encephalopathy and deafness with intermittent episodes of coma and hyperkynureninuria.

Six of nine children born from first-cousin parents presented with the same clinical picture: non-progressive congenital encephalopathy with marked hypertonia resembling the stiff-baby syndrome, delayed milestones, mental deficiency and congenital deafness. Rare, usually reversible, episodes of sudden worsening of the neurological status, with progressive loss of consciousness and increase of hypertonia, occurred spontaneously or during febrile illnesses. During these periods, and sometimes on other occasions, transitory renal dysfunction was observed (nephrotic syndrome and/or tubular abnormalities). Death occurred before age 2 years in 4 patients; 2 are still alive (10 and 13 years old). Electrophysiological, biological and enzymatic investigations remained negative, particularly those concerning mitochondrial and peroxisomal metabolism. The only biochemical anomaly was a massive hyperkynureninuria, seen only during the periods of coma (up to 213 mumol/mmol creatinine; normal < 10) and after an intravenous protein loading test. This suggests an anomaly of tryptophan metabolism which has not been reported up to now.

Algeria↗
PubMed1996

Clinical course, early diagnosis, treatment, and prevention of disease in glutaryl-CoA dehydrogenase deficiency.

BACKGROUND: Glutaryl-CoA dehydrogenase deficiency (GDD) is a recessively inherited neurometabolic disorder associated with encephalopathic crises and severe extrapyramidal symptoms. Treatment regimens including glucose and electrolyte infusions during acute illnesses, oral carnitine supplementation and/or a low-protein or lysine-restricted diet have been recommended, but their efficacy has been documented only on an anecdotal basis. SUBJECTS AND METHODS: We conducted a retrospective analysis of 57 patients with proven GDD-relating appearance and severity of neurological disease to age and clinical status at diagnosis, glutaric acid levels in body fluids, and different treatment regimens. RESULTS: Thirty-six patients were diagnosed after the onset of neurological disease (symptomatic group), twenty-one before (presymptomatic group). Carnitine levels were found to be reduced in all patients at diagnosis. In the symptomatic group, macrocephaly had been present around birth and was followed by rapid postnatal head growth in 70% of the children. The patients often showed symptoms such as hypotonia, irritability, and jitteriness followed by an acute encephalopathic crisis occurring on average at 12 months of age. Common neuroimaging findings included frontotemporal atrophy, subependymal pseudocysts, delayed myelination, basal ganglia atrophy, chronic subdural effusions and hematomas. In four patients the latter two findings were initially misinterpreted as resulting from child abuse. Other important misdiagnoses in older siblings who were affected and went undiagnosed include postencephalitic cerebral palsy, dystonic cerebral palsy and sudden infant death syndrome. Metabolic treatment did not convincingly improve the neurological disease, although it may have prevented further deterioration. Symptomatic treatment with baclofen or benzodiazepines was effective in reducing muscle spasms. Children in the presymptomatic group were diagnosed because of familiarity for the disease (n = 13), macrocephaly and/or additional minor neurological signs in infancy (n = 6), or acute encephalopathy, which was fully reversible after prompt treatment (n = 2). After diagnosis, all children were treated with oral carnitine, fluid infusion during intercurrent illnesses and, in addition, a diet was started in 13 of the 21 children. All 21 children except one (born prematurely at 31 weeks) have continued to develop normally up to now. Mean age at report is 6.3 years with a range from 6 months to 14.8 years. In older patients, the neuroradiological changes, present in infancy as in the symptomatic patients, became less prominent and in one girl disappeared. CONCLUSIONS: In presymptomatic children with GDD, the onset of neurological disease can be prevented by vigorous treatment of catabolic crises during illnesses together with carnitine supplementation. The importance of dietary therapy remains unclear and needs further evaluation. The potential treatability of GDD calls for increased attention to early presenting signs in order to recognize the disorder and to initiate treatment before the onset of irreversible neurological disease.

Adolescent↗
PubMed1996

Magnetic resonance imaging and spectroscopy of the brain in propionic acidemia: clinical and biochemical considerations.

Three patients with propionic acidemia were studied. The first patient was diagnosed at the age of 9 mo, 3 mo after he developed hypotonia and choreoathetoid movements after an upper respiratory tract infection. The second patient was diagnosed at the age of 1.5 mo when she became comatose after nasogastric tube feeding because of failure to thrive. The third patient was diagnosed at the age of 5 d when she presented with feeding difficulties, hypotonia, and respiratory insufficiency. Magnetic resonance imaging (MRI) of the brain in all patients revealed delayed myelination and some cerebral atrophy. In the patient with choreoathetosis, MRI showed bilateral abnormalities in the signal intensity of the putamen and caudate nuclei. MRI of the other two patients showed normal basal ganglia. Proton magnetic resonance spectroscopy (1H MRS) from a voxel located in the basal ganglia revealed a decrease in N-acetylaspartate and myo-inositol peaks and an elevation of glutamine/ glutamate. The presence of spectroscopic abnormalities in a stable metabolic condition, in particular the rise in glutamine/ glutamate, indicates that the metabolic balance on cerebral parenchymal level is less optimal than estimated from biochemical analysis of urine, plasma, or cerebrospinal fluid.

Age of Onset↗
PubMed1996

Effects of progestogen on lipids, lipoproteins and apolipoproteins during transdermal estrogen replacement therapy with and without medroxyprogesterone acetate.

OBJECTIVE: To assess whether the effects on plasma lipids and lipoproteins after oophorectomy differ in patients who receive transdermal estrogen replacement therapy (ERT) with and without progestin. STUDY DESIGN: Twenty-five healthy, normal-weight, regularly menstruating women who underwent hysterectomy and bilateral oophorectomy for benign diseases received, for one year, transdermal therapeutic systems containing estradiol with daily delivery of 50 micrograms cyclically for 24 days per month plus 2.5 mg/d of oral medroxyprogesterone acetate (MPA) sequentially for the last 12 days of each cycle. After the first year the patients ceased to take MPA. We determined the levels of cholesterol (CHOL), high density lipoprotein (HDL)-CHOL, low density lipoprotein (LDL)-CHOL, triglycerides (TG) and apolipoproteins (apo) A-I and B prior to oophorectomy, one month after surgery and during the 6th and 12th months on estrogen plus progestogen substitution and during the 18th and 24th months without progestogen addition. RESULTS: After oophorectomy, the patients showed increases in LDL, apo-B and atherogenic index, whereas after hormone replacement therapy the patients exhibited falls in plasma LDL, apo-B and atherogenic index and increases in HDL and apo A-I. No significant changes in total CHOL were observed after surgery or treatment, and TG were decreased. Plasma levels of lipids and lipoproteins during estrogen replacement therapy (ERT) without MPA were not significantly different from those observed during ERT plus MPA. CONCLUSION: Changes in lipids induced by transdermal ERT were not affected by low doses of MPA.

Administration, Cutaneous↗
PubMed1995

Lymphatic regulation of hematocrit during hypoxia in the toad Bufo woodhousei.

Hypoxia rapidly increases hematocrit (Hct) in anuran amphibians by reducing plasma volume, but the mechanism(s) mediating this response is unknown. We tested the hypothesis that, during hypoxia, plasma volume is reduced by impaired lymph heart (LH) function, decreasing lymph flow into the circulation. In Bufo woodhousei, we measured the effects of hypoxia on Hct, lymph heart rate (LHR), LH pressure, the movement of dye from the dorsal lymph sac to the arterial blood, and flow through an open LH cannula. We also tested whether splenic contraction or cholinergic nerves contribute to the hypoxia-induced changes. Graded hypoxia between 21 and 4% O2 produced graded increases in Hct (P < 0.0001) and decreases in LHR (P = 0.01). Hypoxia reduced the rate of increase in arterial Evans blue concentration after injection into the dorsal lymph sac (P = 0.041) and decreased flow through an open LH cannula (P < 0.012). Hypoxia increased Hct and reduced LHR similarly in control, splenectomized, and sham-splenectomized toads. Atropine had no significant effect on Hct and LHR. These results indicate that the LHs play a regulatory role in hypoxia-induced hemoconcentration.

Animals↗
PubMed1995

D-2-hydroxyglutaric aciduria.

Hydroxyglutaric aciduria is detected by gas chromatographic-mass spectrometric analysis, and the D and L forms are quantified by chemical ionization with deuterated internal standards. Patients have recently been described who accumulate the D form, and they appear to be quite different from those with the more common L form. Experience is reported with three patients and an animal model with D-2-hydroxyglutaric aciduria. The phenotype appears to include mental retardation, macrocephaly, hypotonia, seizures, and involuntary movements, although neurologic and systemic manifestations of the disorder varied considerably between individual patients, even within the same family.

Animals↗
PubMed1995

Trial of routine gonadotropin releasing hormone agonist treatment before abdominal hysterectomy for leiomyoma.

OBJECTIVE: To investigate the usefulness of a routine short term treatment with gonadotropin releasing hormone agonist (D-Trp-6-LHRH depot) before abdominal hysterectomy for leiomyoma. STUDY DESIGN: Prospective, comparative, randomized study. SETTING: A teaching hospital of Barcelona University. PATIENTS: Fifty premenopausal women requiring hysterectomy as treatment for symptomatic leiomyomas. Twenty-three patients were randomized to receive gonadotropin releasing hormone agonist treatment before hysterectomy (cases), and 27 patients were randomized to immediate hysterectomy (controls). MAIN OUTCOME MEASURES: Type of abdominal incision, operating time, operative hemoglobin and hematocrit decrease, postoperative morbidity, and days in hospital. RESULTS: In the agonist treated group mean uterine volume decreased and mean hemoglobin and hematocrit significantly rose after 8 weeks of treatment. Operative time was similar in both groups of patients but the number of women having Pfannenstiel incision was significantly higher in the cases. Mean operative hemoglobin and hematocrit decrease and postoperative morbidity were lower in the cases. There was a trend for shorter postoperative hospital stays in the agonist treated group. CONCLUSIONS: Our results favor the routine use of a short term gonadotropin releasing hormone agonist treatment before abdominal hysterectomy for leiomyoma in order to decrease operative blood loss and postoperative morbidity.

Adult↗