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Biomedical subjects

C A Stanley

Publications and source records attributed to C A Stanley.

At least 73 records · Page 4Linked to original sources
PubMed1992

Elevated plasma carnitine in the hepatic form of carnitine palmitoyltransferase-1 deficiency.

In a boy with a defect in fatty acid oxidation due to the hepatic form of carnitine palmitoyltransferase-1 deficiency, plasma carnitine concentrations were found to be twice normal. The elevation in plasma carnitine levels was accompanied by an unusually high renal threshold for free carnitine, suggesting a secondary increase in carnitine transport. Similar to other fatty acid oxidation disorders involving the carnitine cycle, urinary dicarboxylic acids were not abnormally elevated during illnesses. The combination of elevated plasma carnitine levels and absence of dicarboxylic aciduria may help to distinguish the hepatic form of carnitine palmitoyltransferase-1 deficiency from other defects in fatty acid oxidation.

Blood Glucose↗
PubMed1992

Detection and quantitation of acylcarnitines in plasma and blood spots from patients with inborn errors of fatty acid oxidation.

Acylcarnitine profiling in plasma and dried blood spots by radioisotopic exchange/HPLC demonstrates that MCAD deficiency can be reliably detected in the asymptomatic state without L-carnitine therapy. The OC/AcC ratio differentiates MCAD deficiency from normal controls. A longer chain acylcarnitine (r.t. 43 min.) was detected in all 3 patients with a defect in long chain fatty acid oxidation. Detection of C4- and C5-acylcarnitine isomers in plasma helped characterize a metabolic defect affecting branched chain acyl-CoA oxidation in 3 patients. Quantitative data in 2 patients with MCAD deficiency showed that plasma concentrations of OC and AcC are dependent on both the availability of free carnitine and the severity of metabolic decompensation.

Acyl-CoA Dehydrogenase↗
PubMed1991

Chronic cardiomyopathy and weakness or acute coma in children with a defect in carnitine uptake.

A defect in intracellular uptake of carnitine has been identified in patients with severe carnitine deficiency. To define the clinical manifestations of this disorder, the presenting features of 15 affected infants and children were examined. Progressive cardiomyopathy, with or without chronic muscle weakness, was the most common presentation (median age of onset, 3 years). Other patients presented with episodes of fasting hypoglycemia during the first 2 years of life before cardiomyopathy had become apparent. A defect in carnitine uptake was demonstrable in fibroblasts and leukocytes from patients. The defect also appears to be expressed in muscle and kidney. Concentrations of plasma carnitine and rates of carnitine uptake in parents were intermediate between affected patients and normal control subjects, consistent with recessive inheritance. Early recognition and treatment with high doses of oral carnitine may be life-saving in this disorder of fatty acid oxidation.

Biological Transport↗
PubMed1991

Familial and sporadic hyperinsulinism: histopathologic findings and segregation analysis support a single autosomal recessive disorder.

We evaluated the possible genetic contribution to hyperinsulinism in a series of patients seen during the past 15 years. Of 26 families, 5 (19%) had more than one child affected (multiplex family). There were no apparent differences between patients in the 5 multiplex and 21 simplex families, clinically, biochemically, or on histologic examination of the pancreatic specimens. The families studied had a total of 63 offspring; the 26 index patients had 37 siblings, 6 of whom were affected. After four patients with hyperinsulinism caused by adenoma were excluded from the study, segregation analysis was carried out to test the data for agreement with results expected if familial and isolated hyperinsulinism represented a single disease with recessive mode of inheritance and a segregation ratio of 0.25. Excellent agreement was found between the observed number of affected siblings (20) and the expected number (19.65), with a segregation ratio of 0.254. The results were consistent with the hypothesis that in most or all cases, hyperinsulinism is inherited as an autosomal recessive disease. There was no evidence of distinct familial and sporadic types.

Family Characteristics↗
PubMed1991

Hypoglycemia, hypotonia, and cardiomyopathy: the evolving clinical picture of long-chain acyl-CoA dehydrogenase deficiency.

Inherited defects in fatty acid oxidation, which have been described and diagnosed with increasing frequency in the last decade, are most commonly attributed to a deficiency in the activity of medium-chain acyl-CoA dehydrogenase. Few cases of the related enzyme defect of long-chain acyl-CoA dehydrogenase activity have been reported. An infant with documented long-chain acyl-CoA dehydrogenase deficiency is described with a detailed metabolic profile, long-term clinical follow-up, and response to treatment. This patient is compared with the seven previously published cases of this disorder in order to stress the unique features of the initial presentation, more subtle late manifestations of the disease, and clinical and biochemical differentiation from the more common medium-chain acyl-CoA dehydrogenase deficiency. This report stresses the enlarging spectrum of the clinical presentation and natural history of this defect in fatty acid oxidation.

Acyl-CoA Dehydrogenase, Long-Chain↗
PubMed1990

Impaired metabolic function and signaling defects in phagocytic cells in glycogen storage disease type 1b.

Patients with glycogen storage disease (GSD) type 1b (1b), in contrast to patients with GSD type 1a (1a), are susceptible to recurrent bacterial infections suggesting an impairment in their immune system. In this study, phagocytic cell (neutrophil and monocyte) respiratory burst activity, as measured by superoxide anion generation, oxygen consumption, and hexose monophosphate shunt activity, was markedly reduced in both neutrophils and monocytes from GSD 1b patients as compared with either GSD 1a patients or healthy adult control cells. Degranulation, unlike respiratory burst activity, was not significantly different in neutrophils from GSD 1b patients as compared with controls. Both neutrophils and monocytes from GSD 1b patients showed decreased ability to elevate cytosolic calcium in response to the chemotactic peptide f-Met-Leu-Phe. In addition, calcium mobilization in response to ionomycin was also attenuated suggesting decreased calcium stores. Thus, reduced phagocytic cell function in GSD 1b is associated with diminished calcium mobilization and defective calcium stores. Defective calcium signaling is associated with a selective defect in respiratory burst activity but not degranulation.

Calcium↗
PubMed1989

Medium-chain acyl-CoA dehydrogenase deficiency: metabolic effects and therapeutic efficacy of long-term L-carnitine supplementation.

Medium-chain acyl-CoA dehydrogenase deficiency is a recently described inborn error of metabolism characterized by episodes of coma and hypoketotic hypoglycaemia in response to prolonged fasting. Secondary carnitine deficiency has been documented in these patients as well as the excretion in the urine of medium-chain-length acyl carnitine esters, such as octanoylcarnitine. Based on the potential toxicity of medium-chain fatty acid metabolites and the beneficial responses of patients with other inborn errors of metabolism and secondary carnitine deficiency, oral carnitine has been proposed as treatment for children with medium-chain acyl-CoA dehydrogenase deficiency. We report the results of carefully monitored fasting challenges of an infant with this deficiency both before and after 3 months of oral carnitine therapy. Carnitine supplementation failed to prevent lethargy, vomiting, hypoglycaemia and accumulation of free fatty acids in response to fasting despite normalization of plasma carnitine levels and a marked increase in urinary excretion of acyl-carnitine esters. Potentially toxic medium-chain fatty acids accumulated in the plasma in spite of therapy. Based on this study of one patient, we stress that avoidance of fasting and prompt institution of glucose supplementation in situations when oral intake is interrupted remain the mainstays of therapy for medium-chain acyl-CoA dehydrogenase deficient patients.

3-Hydroxybutyric Acid↗
PubMed1989

Hyperfiltration and renal disease in glycogen storage disease, type I.

A prospective study of 14 patients (ages 6 months to 33 years) with glycogen storage disease, Type I (GSD-I) was carried out in order to define the character and frequency of renal dysfunction. A marked increase in the glomerular filtration rate (GFR) was documented in virtually all subjects, with the mean GFR raised by approximately 50%, to the range of 170 ml/min/1.73 m2. While this constituted the only renal abnormality found in the younger patients, a significant increase in urinary albumin excretion was seen in three teen-aged individuals; three patients over 20 years of age exhibited frank proteinuria (2 to 8 g/day). Renal biopsy on two of the proteinuric subjects revealed focal and global glomerulosclerosis and interstitial fibrosis. Evaluation of factors known to cause an increase in GFR did not define the precise etiology for its elevation in GSD-I. These studies suggest that: (1) glomerular damage and chronic renal disease are common in older patients with GSD-I; (2) the renal injury appears to be specifically related to GSD-I and is not secondary to the treatment of the disease; and (3) the natural history of the renal lesion in GSD-I may be analogous to that seen in insulin-dependent diabetes, with a "silent" period where hyperfiltration is the only demonstrable renal abnormality, followed by evidence of increasing glomerular damage progressing from microalbuminuria to frank proteinuria.

Adolescent↗
PubMed1989

Cerebral metabolic response and mitochondrial activity following insulin-induced hypoglycemia in newborn lambs.

We evaluated the newborn lamb's cerebral cellular activity and metabolism following acute insulin-induced hypoglycemia. Eleven animals received an insulin bolus followed by a continuous infusion to maintain a plasma glucose of 1 mM/l for 2 h, while 8 other animals received an equivalent dose of saline. Following the induction of hypoglycemia, the animals became quiet and transient seizures were observed in 3 animals. A significant increase in heart rate (p less than 0.01), and a decrease in arterial PaCO2 at 30 min (p less than 0.01), and pH at 2 h (p = 0.02), following hypoglycemia, were observed in the experimental group. Hypoglycemia did not significantly alter the cerebral blood flow, mitochondrial respiratory control ratio or the state-3 activity. The cerebral arteriovenous difference (CAVD) for oxygen did not change, while the glucose CAVD was significantly reduced from 0.47 +/- 0.21 to 0.24 +/- 0.16 mM/l (p less than 0.05) at the end of the hypoglycemia period, suggesting consumption of alternate substrates of energy by the brain. Insulin-induced hypoglycemia was associated with a significant increase in arterial lactate (p less than 0.01), and a significant correlation (p less than 0.01) between arterial and CAVD for lactate and beta-hydroxybutyrate (BOB) was observed. Cerebral consumption of alternate substrates of energy was inconsistent, and only observed for lactate in 5 and for BOB in 3 experimental animals following hypoglycemia. These data indicate that the newborn lamb's cerebral cellular activity is not affected by the degree of hypoglycemia achieved in these studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Massive hepatomegaly, steatosis, and secondary plasma carnitine deficiency in an infant with cystic fibrosis.

Hepatomegaly and steatosis are common findings in children with cystic fibrosis and are most often attributed to malnutrition. An infant fed a carnitine-free soy formula is described. Massive hepatomegaly and steatosis developed in the baby at a time of severe viral respiratory illness, prolonged fasting, hypoglycemia, and hypoketonuria. The infant was found to have secondary plasma carnitine deficiency and excessive loss of carnitine in the urine as part of a more generalized renal tubular dysfunction accompanying vitamin D deficiency and secondary hyperparathyroidism. With correction of the metabolic abnormalities and institution of a high carnitine diet, the hepatomegaly disappeared, plasma carnitine returned to normal levels, and the renal carnitine loss ceased. The findings suggest that secondary carnitine deficiency may play a role in fatty infiltration of the liver in patients with cystic fibrosis, especially during times of severe fasting stress.

Carnitine↗