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Biomedical subjects

R Matalon

Publications and source records attributed to R Matalon.

At least 91 records · Page 5Linked to original sources
PubMed1988

Aspartoacylase deficiency and N-acetylaspartic aciduria in patients with Canavan disease.

An increased amount of N-acetylaspartic acid was found in urine and plasma of three patients, from two families, with the diagnosis of cerebral spongy degeneration (Canavan disease). Aspartoacylase was assayed in cultured skin fibroblasts from one patient of each family and a profound deficiency of this enzyme was found. Although the function of N-acetylaspartic acid is not understood, it is known to occur in high concentration in human brain. The finding of a defect in the metabolism of N-acetylaspartic acid causing progressive spongy degeneration of the brain may lead to a better understanding of the function of this amino acid derivative. The aspartoacylase assay affords a new tool for determining the diagnosis of Canavan disease. Since aspartoacylase activity was present in cultured amniotic cells and chorionic villi, it is likely that the assay for this enzyme can be used for the prenatal diagnosis of Canavan disease.

Amidohydrolases↗
PubMed1988

Analysis of the pentafluorobenzoyl derivative of phenylethylamine utilizing negative ion chemical ionization and gas chromatography/mass spectrometry.

A negative ion chemical ionization (NICI) mass spectrometric procedure has been developed to measure phenylethylamine in human urine as the pentafluorobenzoyl derivative. The aromatic amine was isolated from alkaline urine by hexane and ethyl acetate extraction followed by a back-extraction into diluted acid. The acid extract was lyophilized and the residue derivatized with (2,3,4,5,6)-pentafluorobenzoyl chloride. Quantification was achieved by comparing the peak areas of the [M-HF]- ion to a ratio of internal and external standards. The phenylethylamine levels excreted by normal subjects and patients with phenylketonuria were found to be consistent with previous reports.

Benzoates↗
PubMed1988

Carrier detection for Sanfilippo A syndrome.

In Sanfillipo A families, sulphamidase activities in leukocytes and cultured fibroblasts determined at 55 degrees C distinguish between heterozygote-carriers, normal individuals and the homozygotes.

Genetic Carrier Screening↗
PubMed1988

Phenylalanine metabolites as indicators of dietary compliance in children with phenylketonuria.

The data from this study showed that the excretion of three major metabolites of phenylalanine in patients with PKU approach normal values at blood phenylalanine levels less than 5.0 mg/dl. The MANOVA showed statistically significant differences in phenyllactate excretion when blood phenylalanine was greater than 10.0 mg/dl. The PL and total metabolite excretion were significantly correlated to blood phenylalanine in multiple samples taken from two individual subjects. Using data obtained from single patient observations may serve as a means for individualizing the PKU diet to insure low levels of phenylalanine metabolites and thus insure optimal development for patients with PKU.

Adolescent↗
PubMed1988

Blood phenylalanine levels and intelligence of 10-year-old children with PKU in the National Collaborative Study.

Dietary intakes and blood phenylalanine levels of 125 10-year-old children with PKU are reported. Of those patients, 59 discontinued the special diet at 6 years, 16 discontinued at 8 years, 5 discontinued at 6 years but returned to the diet at 8 1/2 years, and 45 continued the diet to 10 years. Phenylalanine intake was determined by 2-day diet records. Blood phenylalanine concentrations revealed a lack of clear distinction between the diet groups; therefore, regression analysis was performed on the group as a whole. The analyses revealed significant relationships between blood phenylalanine levels from ages 6 to 10 years and each of the cognitive outcome variables, after the influences of parental IQ and the age at which treatment was initiated were controlled for. Intelligence test scores were also related to phenylalanine levels between ages 3 1/2 and 5 1/2 years. The findings suggest that dietary restriction of phenylalanine should continue in patients with PKU through at least 10 years of age.

Child↗
PubMed1987

Phenotypic features of patients with congenital adrenal hypoplasia and glycerol kinase deficiency.

Two unrelated boys with congenital adrenal hypoplasia and glycerol kinase deficiency were found to have similar features, including characteristic facies, testicular abnormalities, short stature, psychomotor retardation, and muscular dystrophy. The resemblance of these boys to other patients described in the literature suggests that a distinct phenotypic syndrome occurs in children with congenital adrenal hypoplasia and glycerol kinase deficiency.

Adrenal Insufficiency↗
PubMed1987

Dominant inheritance of a syndrome similar to Rubinstein-Taybi.

Two sibs and their mother were affected with a syndrome like the Rubinstein-Taybi syndrome. All three individuals had broad terminal phalanges of the thumbs and great toes, antimongoloid slant of the palpebral fissures, and characteristic facial appearance with beaked noses. Four sibs of the mother had broad thumbs, suggesting a familial pattern. So far there has been no report of dominant transmission of the Rubinstein-Taybi syndrome. This family bears close resemblance to the Rubinstein-Taybi syndrome, which is transmitted as an autosomal or X-linked dominant trait. Inasmuch as the expressivity of the syndrome may be variable, we propose that a thorough family investigation is indicated in all apparently sporadic cases of Rubinstein-Taybi syndrome. Familial cases may be more common than realized and require appropriate genetic counseling.

Abnormalities, Multiple↗
PubMed1986

Galactokinase activity in patients with idiopathic cataracts.

Ninety-four consecutive patients admitted for elective cataract surgery were prospectively examined for erythrocyte galactokinase activity. The presumed etiology for the cataract was established by history and physical examination in 51 patients (21 were diabetic). The cataract was classified as idiopathic in 43 patients. Galactokinase activity was significantly lower in idiopathic vs. presumed (nondiabetic) etiology patients 50 years of age or younger (P less than 0.05) and in idiopathic cataract patients 50 years of age or younger vs. those older than 51 years of age (P = 0.0033). Three of the idiopathic cataract patients (6.9%) had galactokinase levels less than two standard deviations below the mean galactokinase level for age-matched patients with suspected (nondiabetic) etiology. Compared with the expected distribution for the heterozygote in the general population (0.2%), this was highly significant (P = 0.0001). Diminished galactokinase activity may increase the risk of developing presenile cataracts requiring surgery by the fourth decade.

Adult↗
PubMed1986

Sanfilippo disease in Greece.

In a series of cases collected in most parts of the world, Sanfilippo disease type A is more frequent than type B. Skin biopsies were obtained from Greek patients suspected for Sanfilippo disease and cultured fibroblasts were assayed for both N-acetyl-a-glucosaminidase and sulfamidase activity. Eleven patients with Sanfilippo disease were identified. Ten of them were type B and one type A. The 10 patients with type B came from East-Central Greece and the neighboring areas of Thessaly and Macedonia. Both parents of the type A patient were from the Greek ethnic community of Turkey. It remains unknown whether or not the higher frequency of type B than type A appears only in Greece or if it occurs in other Mediterranean countries as well.

Acetylglucosaminidase↗
PubMed1986

Maternal PKU: strategies for dietary treatment and monitoring compliance.

Blood phenylalanine and the metabolites of phenylalanine can be dramatically lowered in pregnant PKU mothers. Special formulas and a strict protocol should be used to achieve diet control and adequate compliance. Levels of blood phenylalanine of 4 mg/dl and lower can be achieved and are preferable to higher levels. The problem of treatment postconception may lead to limited success, as in our case. In order to achieve optimal results, blood phenylalanine should be controlled at or before conception. Since it is difficult to return patients to diet who have been taken off phenylalanine restriction, diet therapy for PKU should not be discontinued at any age.

Adolescent↗
PubMed1985

A therapeutic trial of amniotic epithelial cell implantation in patients with lysosomal storage diseases.

To determine whether allografts of normal amniotic epithelium might provide a nonimmunogenic cellular source of exogenous lysosomal enzymes, subcutaneous implants of amniotic epithelium were performed in six children with clinically advanced storage diseases. The clinical and the biochemical status of each patient was observed for several weeks after amniotic epithelial cell implantation (AECI). Serial studies of blood samples from each patient in the post-AECI period did not demonstrate any increase in levels of deficient lysosomal hydrolase. In two patients, quantitative urinary excretion of substrate was also studied and did not show consistent alterations after AECI. No patient had objective improvement in clinical or neurodevelopmental status following AECI. Two patients died with progressive disease at 2 1/2 and 3 1/2 mo after AECI; no residual amniotic epithelium was found at postmortem examination. Four patients are alive with progressive disease at 6-14 mo after AECI. We conclude that allografts of normal human amnion do not provide sufficient replacement hydrolases for clinical or biochemical improvement in lysosomal storage diseases.

Amidohydrolases↗
PubMed1985

Phenylalanine metabolites, attention span and hyperactivity.

The metabolites of phenylalanine, phenylacetate, phenyllactate, phenylpyruvate and phenylethylamine, were measured in the urine of PKU patients. In general correlation was found between serum phenylalanine excretion of these metabolites. However, there were individual variations in the quantities and type of metabolites excreted that could not be explained by blood phenylalanine levels. In a PKU pregnancy large quantities of phenylalanine metabolites were found in urine despite a modest elevation of serum phenylalanine. Increase in the excretion of phenylalanine metabolites was found in patients who were considered to have good blood phenylalanine control. These preliminary studies indicate that the current practice of allowing a wide range of blood phenylalanine in the treatment of PKU may have to be reexamined. Since these metabolites are neurotoxic, they may afford a new parameter for the study of PKU not only regarding the prevention of mental retardation but also with regards to behavior and learning disabilities.

Adolescent↗
PubMed1985

Craniofacial and mucopolysaccharide abnormalities in Kniest dysplasia.

Serial roentgencephalograms of a male patient with Kniest dysplasia were obtained between 1 7/12 and 11 3/12 years of age and were analyzed and compared to cephalometric normative data. The patient displayed macrocephaly with increased size of the neurocranium in all three dimensions. The cranial base angle was significantly flattened, partly as a result of anterior displacement of the sella turcica. The odontoid process was short and wide. At 11 years of age there was bony fusion between the anterior arch of the atlas and the odontoid process as well as between the posterior arch of the atlas and the cranial base. The facial skeleton, including the nasal bones, infra-orbital rims, maxilla and mandible, was retropositioned relative to the anterior cranial base. The mandibular retrognathia was pronounced at an early age but improved with growth. At age 11 years the patient had a straight facial skeletal profile. Examination of the patient's 24-hour urinary excretion of keratan sulfate revealed values markedly elevated for his age. Three additional patients with Kniest dysplasia demonstrated similarly increased excretion of this glycosaminoglycan. The diagnosis of Kniest dysplasia can usually be made from roentgenograms of the extremities, the spine, and the pelvis. However, the morphologic characteristics of the head, as shown by cephalometric analysis, and the increased urinary excretion of keratan sulfate add confirmatory evidence useful in differential diagnosis.

Cephalometry↗
PubMed1984

Treatment of the cbl B form of methylmalonic acidaemia with adenosylcobalamin.

A 30-month-old girl was found to have the cbl B mutant form of methylmalonic aciduria by complementation analysis of fibroblasts. She was unresponsive to hydroxycobalamin and was treated with intramuscular adenosylcobalamin (AdoCbl), the deficient coenzyme, at a dose of 1 mg/24h during a period of clinical stability. Serum cobalamin increased from 770 to 54 200 pg/ml. Mean urinary methylmalonic acid excretion was 409 mg/24 h prior to therapy. There was a transient fall in methylmalonic acid excretion during the first 5 days of therapy (range 167-245 mg/24h) followed by a rise in excretion toward pretreatment levels (range 317-485 mg/24h) during the second week of AdoCbl treatment. There was no change in plasma ammonia, glycine or serum bicarbonate level. We interpret the failure of this child to have a sustained and clinically significant response to AdoCbl as indicating that AdoCbl did not reach or enter the mitochondria intact, or in some other way was unavailable as a coenzyme for the methylmalonyl CoA mutase apoenzyme.

Amino Acid Metabolism, Inborn Errors↗