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Biomedical subjects

N Bashan

Publications and source records attributed to N Bashan.

At least 73 records · Page 4Linked to original sources
PubMed1987

Impaired glucose transport in polymorphonuclear leukocytes in glycogen storage disease Ib.

A study of 2-deoxyglucose transport into polymorphonuclear leukocytes (PMN) was performed in three patients with glycogen storage disease (GSD) type Ib. The rate of 2-deoxyglucose transport into GSD Ib PMN was 30% of that of cells of normal controls. In GSD Ib lymphocytes, transport was normal. Km for 2-deoxyglucose in the PMN of one patient was within the normal range. The reduced transport was not due to the elevation in Km for 2-deoxyglucose nor to the decreased rate of phosphorylation of 2-deoxyglucose. The striking limitation of glucose transport across the cell membrane may account for the impairment of leukocyte function which is characteristic of GSD Ib.

Antiporters↗
PubMed1987

An algorithmic approach to diagnosis of hypoglycemia.

An algorithm has been devised to facilitate the diagnostic approach to the causes of hypoglycemia. This systematic approach enables the physician to reach the final diagnosis in a logical way without subjecting the child to unnecessary and possibly hazardous investigations. The algorithm is based on the following measurements as required by each patient: concentrations of blood glucose, lactate, ketone bodies, and glucose-regulating hormones. These measurements are performed with the patient in the fasting state and after loading tests (glycerol and galactose) as needed. If indicated, an enzymatic test is performed to establish the final diagnosis. Eighteen children aged 1 month to 7 years who had persistent or recurrent hypoglycemia have been examined according to this algorithm. The correct diagnosis was arrived at in 17 patients. The diagnosis was not reached in one neonate who had glucose-6-phosphatase deficiency and initially did not have lactic acidosis; once lactic acidosis developed, his illness fitted perfectly into the algorithm.

Algorithms↗
PubMed1987

The effect of the duration of the second stage of labour on the acid-base state of the fetus.

A prospective study was made in 153 patients with a second stage of labour lasting 1 to 120 min. Maternal venous, umbilical artery and vein blood were analysed for acid-base variables and lactate levels. Blood was obtained immediately at delivery. Fetal heart rate monitoring data and blood test results were related to the duration of the second stage of labour and clinical outcome. In primiparae and multiparae there was a steady rise in umbilical artery lactate levels, with duration of second stage of labour, P less than 0.025 and P = 0.023, respectively. The median umbilical artery pH decreased significantly from 7.31 in patients with a second stage of labour that lasted less than or equal to 15 min to a pH of 7.25 in patients with a second stage of labour that lasted more than 30 min. Changes in PO2 and PCO2 were not statistically significant.

Acid-Base Equilibrium↗
PubMed1987

Maple syrup urine disease in a Bedouin tribe: pre- and postnatal diagnosis.

Maple syrup urine disease (MSUD) was diagnosed in four Bedouin infants as a result of the lack of branched-chain keto amino acids (BCKA) decarboxylase activity in leukocytes and skin fibroblasts. Second trimester amniocenteses were performed in five at risk pregnancies for measurement of BCKA decarboxylase. The activity measured in amniocytes was undetectable in two of them. Pregnancy was terminated only in one case and the second continued to term. The diagnosis of MSUD was confirmed in tissues of one aborted fetus, and in leukocytes of the liveborn infant. The other three pregnancies, in which normal enzymatic activity was found in the amniotic cells, were carried to term, and BCKA decarboxylase activity was evident in the leukocytes.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1986

Neuromuscular involvement in glycogen storage disease type III.

Sixteen patients with glycogen storage disease type III (GSD III) aged 3 to 22 years underwent a detailed neuromuscular evaluation. A minimal impairment of skeletal muscle function was presented in eight patients, slight impairment in four and severe impairment in one patient. Serum creatinine phosphokinase (CPK) was elevated in all patients studied. In the nine patients, in whom electromyography (EMG) was performed; six exhibited a myopathic pattern while a "mixed" (neurogenic-myopathic) pattern was present in three. Muscle biopsies performed in 12 patients, revealed in all cases amylo-1,6,-glucosidase deficiency and biochemical as well as morphological evidence of glycogen accumulation. Two brothers suffered from late onset myopathy, which in the older sibling was associated with clinical, EMG and EM findings of a peripheral neuropathy. Fifteen patients had either electrocardiographic and or echographic evidence of cardiomyopathy. Observations based on this patient material suggest a widespread myopathy in GSD III patients with heterogeneous expression, while peripheral nerve involvement is rarely encountered.

Adolescent↗
PubMed1986

Adult muscle phosphorylase "b" kinase deficiency.

A 35-year-old man had severe exercise intolerance and cramps. Venous blood lactate did not rise after ischemic exercise, and electromyographically silent contracture of hand muscles appeared. Histochemistry and electronmicroscopy of a muscle biopsy revealed subsarcolemmal and intermyofibrillar accumulation of glycogen. Biochemical studies showed moderately increased amount of glycogen. Total phosphorylase activity was normal, but the active form "a" was 27% of normal. Phosphorylase kinase activity was 12% of the normal value and was normal in leukocytes and erythrocytes.

Adult↗
PubMed1984

The effect of ions and ionophores on cystine egress from human leucocyte lysosome-rich granular fraction.

This paper describes the stimulation of exodus of cystine from lysosome-rich granular fractions by potassium. Potassium permeability into lysosomes is low, but in the presence of an ionophore or permeable anion, the movement of K+ into lysosomes caused a large stimulation of cystine exodus. Lysosomal preparations from leucocytes of cystinotic patients, which lack carrier-mediated cystine transport, also manifested stimulation of cystine egress by valinomycin and K+. This suggests that potassium-dependent cystine egress involves a carrier different from that defective in cystinosis, or occurs through a non-carrier-mediated mechanism.

Cations, Monovalent↗
PubMed1984

Lysosomal cystine counter-transport in heterozygotes for cystinosis.

Heterozygotes for cystinosis exhibited approximately half the normal rate of cystine counter-transport into isolated leukocyte lysosomes. This gene-dosage effect strongly supports previous findings demonstrating that the basic defect in cystinosis is impaired cystine transport across the lysosomal membrane. The method was used to determine the cystinosis carrier status for siblings of affected children in two families with cystinosis.

Biological Transport↗
PubMed1983

Characteristics of cystine counter-transport in normal and cystinotic lysosome-rich leucocyte granular fractions.

Normal leucocyte lysosome-rich granular fractions exhibited counter-transport of cystine, confirming that cystine transport across the lysosomal membrane is carrier-mediated. The trans-activation of cystine transport was temperature-dependent but relatively independent of the external Na+ or K+ concentration in phosphate buffer. Counter-transport, measured as uptake of exogenous [3H]cystine, increased with increasing intralysosomal cystine content up to approx. 3 nmol of half-cystine/unit of hexosaminidase activity. The amount of [3H]cystine entering lysosomes loaded with unlabelled cystine decreased when unlabelled cystine was added to the extralysosomal medium. Lysosomal cystine counter-transport was stereospecific for the L-isomer. Cystathionine, cystamine and cysteamine-cysteine mixed disulphide gave evidence of sharing the lysosomal cystine-transport system, although at lower activity than cystine. Other tested amino acids, including arginine, glutamate and homocystine, were inactive in this system. Nine leucocyte lysosome-rich preparations from eight different cystinotic patients displayed virtually no counter-transport of cystine, conclusively establishing that a carrier-mediated system for cystine transport is dysfunctional in cystinotic lysosomes.

Amino Acids↗
PubMed1983

Amino acid disturbances in type III glycogenosis: differences from type I glycogenosis.

The plasma glucose, insulin, glucagon, lactate and amino acid response patterns to glucose and protein meals were examined in 11 patients with type III glycogen storage disease (GSD-III). The amino acid metabolism in GSD-III was shown to differ from that observed in normal subjects and in type I glycogen storage disease (GSD-I) patients. The outstanding findings involved the principal gluconeogenic amino acid, alanine. Postabsorptive levels of alanine in GSD-III were significantly below those of normal controls. Following glucose ingestion, alanine rose markedly in GSD-III, which differed from normal subjects in whom no change occurred, and from GSD-I patients in whom a sharp fall was observed. Following beef ingestion, the direction of change of alanine was similar in the three groups, but the circulating levels in GSD-III were significantly less than those observed in GSD-I and normal controls. The possibility that gluconeogenesis is enhanced in GSD-III was supported by the prompt rise in blood glucose observed following beef ingestion, which differed from GSD-I and normal subjects, in which no rise in glucose was observed.

Adolescent↗
PubMed1982

Cystine transport is defective in isolated leukocyte lysosomes from patients with cystinosis.

The activity of a cystine transport system in lysosomes prepared from the leukocytes of patients with cystinosis was found to be deficient. In normal subjects, this system was resistant to N-ethylmaleimide and demonstrated saturation kinetics. Lysosomes from individuals heterozygous for cystinosis demonstrated a reduced maximum velocity for cystine egress from lysosomes. The rate of cystine escape from normal lysosomes was enhanced by adenosine triphosphate. The availability of normal and mutant lysosomes provides a means of investigating mechanisms of amino acid transport across lysosomal membranes.

Biological Transport↗
PubMed1982

A new variant of glycogen storage disease. Type IXc.

Three siblings, a body and two girls, had clinical, laboratory, and morphologic findings that were suggestive of glycogen storage disease (GSD) type IXa. Patients of both sexes with phosphorylase kinase (PK) deficiency usually have an excessive glycogen content only in the liver and normal glycogen content and PK activity in muscle. The siblings in this study had an increased glycogen content in the liver but also in muscle and reduced PK activity in liver, muscle, erythrocytes, and leukocytes. This condition should be labeled as GSD type IXc.

Child, Preschool↗