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Biomedical subjects

M Duran

Publications and source records attributed to M Duran.

At least 217 records · Page 12Linked to original sources
PubMed1987

Neisseria meningitidis strains with decreased susceptibility to penicillin.

Neisseria meningitidis strains relatively resistant to penicillin were recovered from blood or cerebrospinal fluid cultures of four children treated in Barcelona, Spain, and surrounding areas. The four strains had distinct serogrouping and serotyping patterns. The minimal inhibitory concentrations of penicillin were 0.25 microgram/ml for three strains and 0.5 microgram/ml for the fourth strain. These are the first relatively penicillin-resistant meningococcal strains identified in Spain.

Child↗
PubMed1987

Chemical diagnosis of inherited defects of fatty acid metabolism and ketogenesis.

Urinary organic acid profiles in patients with inherited defects of fatty acid metabolism and ketogenesis are described. Medium-chain acyl-CoA dehydrogenase, short-chain acyl-CoA dehydrogenase, multiple acyl-CoA dehydrogenase, and 3-hydroxy-3-methyl-glutaryl-CoA lyase deficiencies can be recognized at the metabolite level. Data on long-chain acyl-CoA dehydrogenase and systemic carnitine deficiencies are scarce. In the latter disorders, dicarboxylic aciduria is rather nonspecific and points to a modest omega-oxidation of long chain fatty acids.

Acyl Coenzyme A↗
PubMed1987

A new case of purine nucleoside phosphorylase deficiency: enzymologic, clinical, and immunologic characteristics.

Deficiency of purine nucleoside phosphorylase (PNP) was detected in a 3-yr-old boy who was admitted for investigation of a behavior disorder and spastic diplegia. The urinary excretion of purines, analyzed by high-performance liquid chromatography, showed the presence of large amounts of (deoxy)inosine and (deoxy)guanosine and low uric acid levels. Analysis of the (deoxy)nucleotide pools of erythrocytes showed elevated levels of deoxyguanine nucleotides and NAD and decreased guanine nucleotides. PNP activity in red blood cells was 0.1-0.5% of normal on two occasions and undetectable on four later measurements. Furthermore no immunoreactive material could be detected in his red cell lysate using an anti-PNP antiserum. PNP activities in the red cells of the patient's parents were 35 and 50% of normal. The presence of (minor) residual PNP activity in the patient enabled the investigation of some enzyme properties after partial purification. No abnormalities could be detected in substrate affinity for inosine, heat stability, and electrophoretic properties. In the heterozygous parents no signs of a mutant enzyme could be found. The molecular specific activities of the parental enzymes were also normal, indicating that no immunoreactive material attributable to inactive-mutant enzyme subunits was present. A striking feature of the patient is the prevailing neurologic abnormalities presumably caused by the metabolic disorder. A severe lymphopenia exists; however, clinical symptoms of an immune deficiency did not become apparent until the age of 4 yr.

Attention Deficit Disorder with Hyperactivity↗
PubMed1987

D-glyceric acidemia: an inborn error associated with fructose metabolism.

A mentally retarded girl with epileptic seizures is described. Urinary organic acid screening revealed a massive excretion of glyceric acid, a normally barely detectable metabolite. Hyperglycinemia was not observed. Capillary gas chromatography of the O-acetylated (-)-menthyl ester of urinary glyceric acid showed the substance to have the D-configuration. The urinary D-glycerate excretion remained unaltered after an oral load with 200 mg/kg L-serine, but oral loading with fructose (1 g/kg) or dihydroxyacetone (1 g/kg) caused a sharp increase of the D-glycerate excretion. Treatment with a diet moderately restricted in fructose led to some clinical improvement as judged by subjective criteria. The metabolic lesion is thought to be located at some step of the fructose catabolic pathway, possibly at the level of hepatic triokinase deficiency.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1986

Diagnosis of inherited adenylosuccinase deficiency by thin-layer chromatography of urinary imidazoles and by automated cation exchange column chromatography of purines.

Patients with inherited adenylosuccinase deficiency excrete large quantities of succinyloaminoimidazolecarboxamide riboside (SAICAR) and succinyloadenosine (SAdo). A two-dimensional thin-layer chromatography method for the detection of SAICAR is described. The method consists of isolation of imidazoles with a cation exchange resin; TLC on cellulose plates, solvent I, isopropanol-ammonia 10% (4:1) and II, butanol-acetic acid-water (4:1:1); detection with Pauly reagent. SAICAR gives rise to an isolated spot with a characteristic bluish color. Also a simple one-dimensional thin-layer chromatography method using urine without any pretreatment for screening of high risk populations is given. Four new cases could be diagnosed. Clinical and chemical data, including concentrations of SAICAR and SAdo in urine, plasma and cerebrospinal fluid, determined by cation exchange column chromatography, are presented.

Adenosine↗
PubMed1986

Functional and mechanistic studies on the toxicity of deoxyguanosine for the in vitro proliferation and differentiation of human peripheral blood B lymphocytes.

Deoxyguanosine (dGuo) has been implicated as the toxic metabolite causing a severe impairment of cellular immunity in children with a genetic deficiency of purine nucleoside phosphorylase (PNP). In peripheral blood T cells of normal donors both the pathway which leads to phosphorylation of dGuo (ultimately resulting in deoxyguanosine triphosphate, dGTP) and the salvage pathway which starts with degradation of dGuo by PNP (resulting in the formation of guanosine triphosphate, GTP) contribute to the inhibition of proliferation. In normal peripheral blood B cells, addition of dGuo leads to an inhibition of proliferation and differentiation. The concentrations of dGuo needed to cause a 50% inhibition are equivalent for peripheral blood T cells and B cells. Inhibition of B cell differentiation can be observed at the level of intracytoplasmic as well as secreted Ig and concerns all Ig isotypes. The early phase of B cell activation which takes place during a 24-h preculture with formalinized Cowan I Staphylococci is not affected by dGuo; it is not until proliferation and differentiation of B cells, brought about by culturing in the presence of crude concanavalin A supernatant, occurs that inhibitory effects of dGuo become evident. Addition of dGuo to B cell cultures results in an intracellular accumulation of GTP and dGTP. Addition of 8-aminoguanosine, a PNP inhibitor, next to dGuo, completely prevents the dGuo-mediated inhibition. Under these circumstances the dGuo-mediated increase in intracellular GTP is abrogated while dGTP accumulation still occurs. This indicates that the inhibitory effect of dGuo on the proliferation and differentiation of peripheral blood B lymphocytes of normal donors is independent of dGTP accumulation.

Adenine↗
PubMed1986

Detection of inherited adenylosuccinase deficiency by two dimensional thin layer chromatography of urinary imidazoles.

Patients with inherited adenylosuccinase deficiency excrete large quantities of succinyloaminoimidazolecarboxamide riboside (SAICAR) and succinyloadenosine (SAdo). A two dimensional thin layer chromatography method for the detection of SAICAR is described. The method consists of 1: isolation of imidazoles with a cation exchange resin; 2: tlc on cellulose plates, solvent I: isopropanol-ammonia 10% (4:1) and II: butanol-acetic acid-water (4:1:1); detection with Pauly reagent. SAICAR gives rise to an isolated spot with a characteristic bluish color. Also a simple one dimensional thin layer chromatography method for screening of high risk populations is given. Four new cases could be diagnosed. Clinical and chemical data, including concentrations of SAICAR and SAdo in urine, plasma and cerebrospinal fluid, determined by column chromatography, are presented.

Adenosine↗
PubMed1986

Direct identification of propionylcarnitine in propionic acidaemia: biochemical and clinical results of oral carnitine supplementation.

Urinary short-chain acylcarnitine in a patient with propionic acidaemia and low levels of free carnitine was found to consist mainly of propionylcarnitine. The compound was isolated by sequential paper and thin layer chromatography and identified by ammonia desorption chemical ionization mass spectrometry. Treatment of the patient with oral carnitine supplements led to a near-normalization of the plasma free carnitine concentrations and an increase in his muscle tone. The propionylcarnitine excretion rose and there was a simultaneous decrease in the methylcitrate output. Carnitine treatment did not prevent the occurrence of an episode of metabolic decompensation.

Amino Acid Metabolism, Inborn Errors↗
PubMed1986

Deficiency of 3-methylglutaconyl-coenzyme A hydratase in two siblings with 3-methylglutaconic aciduria.

We studied two patients with 3-methylglutaconic aciduria in order to determine the molecular defect. A new assay for 3-methylglutaconyl-coenzyme A (CoA) hydratase has been developed in which the substrate, [5-14C]3-methylglutaconyl-CoA, was synthesized using 3-methylcrotonyl-CoA carboxylase purified from bovine kidney. In this assay the products of the reaction are isolated by reverse-phase high performance liquid chromatography and the rates of conversion from substrate are measured. The Michaelis constant for 3-methylglutaconyl-CoA in normal fibroblasts was 6.9 mumol/liter. The mean activity of 3-methylglutaconyl-CoA hydratase in control fibroblasts was 495 pmol/min per mg protein. In the two patients the values were 11 and 17 pmol/min per mg protein, or 2-3% of normal.

Amino Acid Metabolism, Inborn Errors↗
PubMed1986

Sudden child death and 'healthy' affected family members with medium-chain acyl-coenzyme A dehydrogenase deficiency.

A family is described in which the father and three (and probably all four) of his children had a decreased capacity for the oxidation of medium-chain fatty acids. One of the children suddenly died at the age of 16 months following an episode of a rapidly deteriorating Reye syndrome-like illness with hypoketotic hypoglycemia and dicarboxylic aciduria, but without any previous alarming symptoms. The eldest sibling had died at the age of 19 months under similar conditions. The other family members had always been healthy. On fasting, all affected family members accumulated in their plasma the medium-chain fatty acids octanoic, decanoic, and cis-4-decenoic acids. Their urinary organic acid excretion profile could be characterized as "dicarboxylic aciduria." A deficiency of medium-chain acyl-coenzyme A dehydrogenase was demonstrated in a postmortem liver sample of the index patient. Cultured fibroblasts from the father and the two healthy children had a decreased rate of [14C]octanoate oxidation. It is suggested that a deficiency of medium-chain acyl-coenzyme A dehydrogenase may lead to a life-threatening illness when other complicating factors such as diarrhea and vomiting result in an abnormal depletion of the body's glycogen stores. Careful monitoring of at-risk patients during a minor illness is necessary.

Acyl-CoA Dehydrogenase↗
PubMed1985

Octanoylglucuronide excretion in patients with a defective oxidation of medium-chain fatty acids.

Octanoyl-beta-D-glucuronide was identified in the urine of five patients with hypoketotic hypoglycemia and dicarboxylic aciduria due to a defective beta-oxidation of medium-chain fatty acids. Two subjects who ingested large amounts of medium-chain triglycerides also excreted large amounts of the glucuronide. The substance was extracted from the urine with ethyl acetate and analyzed by: (1) gas chromatography/mass spectrometry (GC-MS) of the trimethylsilyl derivative and (2) preparative one-dimensional thin-layer chromatography followed by enzymatic hydrolysis with beta-glucuronidase and again GC-MS. A quantitative analysis was performed indirectly by measuring the urinary bound octanoate after the removal of octanoylcarnitine. Octanoylglucuronide represents an additional mechanism for the detoxification of octanoate; its formation may be of help for the maintenance of carnitine homeostasis in patients with medium-chain acyl-CoA dehydrogenase deficiency.

Acyl-CoA Dehydrogenase↗
PubMed1985

Thiamine-responsive inborn errors of metabolism.

Three different inherited disorders are known in which thiamine may exert a beneficial effect: maple syrup urine disease (MSUD), lactic acidaemia and the syndrome of megaloblastic anaemia with sensorineural deafness and diabetes mellitus. The amounts of thiamine which were used for long-term treatment varied from 20 to 2400 mg day-1. Additional treatment, such as the reduction of dietary branched chain amino acids in MSUD, could not be omitted in some cases. It has been shown that the vitamin improves the stability of the branched chain ketoacid decarboxylase, although some weeks may be needed to observe the in vivo effect of treatment. A prolonged trial with high doses of thiamine should always be given.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗