[Hypoglycemia in newborn infants: failing strips].
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Blood Chemical Analysis↗
Biomedical subjects
R Rodrigues Pereira
Publications and source records attributed to R Rodrigues Pereira.
Primary carnitine deficiency.
Carnitine deficiency can be defined as a decrease of intracellular carnitine, leading to an accumulation of acyl-CoA esters and an inhibition of acyl-transport via the mitochondrial inner membrane. This may cause disease by the following processes. A. Inhibition of the mitochondrial oxidation of long-chain fatty acids during fasting causes heart or liver failure. The latter may cause encephalopathy by hypoketonaemia, hypoglycaemia and hyperammonaemia. B. Increased acyl-CoA esters inhibit many enzymes and carriers. Long-chain acyl-CoA affects mitochondrial oxidative phosphorylation at the adenine nucleotide carrier, and also inhibits other mitochondrial enzymes such as glutamate dehydrogenase, carnitine acetyltransferase and NAD(P) transhydrogenase. C. Accumulation of triacylglycerols in organs increases stress susceptibility by an exaggerated response to hormonal stimuli. D. Decreased mitochondrial acetyl-export lowers acetylcholine synthesis in the nervous system. Primary carnitine deficiency can be defined as a genetic defect in the transport or biosynthesis of carnitine. Until now only defects at the level of carnitine transport have been discovered. The most severe form of primary carnitine deficiency is the consequence of a lesion of the carnitine transport protein in the brush border membrane of the renal tubules. This defect causes cardiomyopathy or hepatic encephalopathy usually in combination with skeletal myopathy. In a patient with cardiomyopathy and without myopathy, we found that carnitine transport at the level of the small intestinal epithelial brush border was also inhibited. The patient was cured by carnitine supplementation. Muscle carnitine increased, but remained too low. This suggests that carnitine transport in muscle is also inhibited. Carnitine transport in fibroblasts was normal, which disagrees with literature reports for similar patients.
Carnitine↗
[Pathogenesis and pathophysiology of carnitine deficiency, a predictable risk].
When patients suffer from hepato-encephalopathy, (cardio)myopathy, dystrophy, hypoglycaemia, some metabolic diseases and several other disease states, carnitine deficiency should be considered. In this article a survey is given of the pathophysiology, laboratory diagnostics, clinical symptomatology and some therapeutic approaches. Some different cases will be demonstrated.
Adult↗
Carnitine deficiency, mitochondrial dysfunction and the heart. Identical defect of oxidative phosphorylation in muscle mitochondria in cardiomyopathy due to carnitine loss and in Duchenne muscular dystrophy.
Cardiomyopathies are often caused by a metabolic defect. Carnitine deficiency and mitochondrial defects in the metabolism of acyl-CoA, including defects in oxidative phosphorylation, start the same circular mechanism of mitochondrial doom. Patients with cardiomyopathy due to carnitine loss are cured by carnitine supplementation. In such a patient we found defective oxidative phosphorylation in isolated muscle mitochondria. The stimulation of the respiratory rate with all substrates by ADP was decreased, probably the cause of inhibition of the adenine nucleotide translocator by accumulating long-chain acyl-CoA. The same condition was encountered in patients with Duchenne muscular dystrophy, who often get cardiomyopathy in the course of the disease process.
Acetyl Coenzyme A↗
[Rhesus antagonism, sometimes different from usual].
We describe three children with an active rhesus antagonism. However, laboratory results and course were different than usual. The first child had blood-type O positive, while his mother had blood-type O positive as well. The mother of the second child had blood-type A negative, while the child seemed to be A negative too. The third child needed an exchange transfusion due to a 'regular' rhesus antagonism, but died shortly after. The mother of the first child turned out to have a rhesus D VI variant. The second child had a 'blocked' D-antigen due to excess anti-D antibodies. The illness of the third child looked like Graft versus Host disease clinically, but eventually appeared to have congenital myelofibrosis. A correct diagnosis in these children is of great importance in future pregnancies, blood transfusions and genetic counseling.
Antibody-Dependent Cell Cytotoxicity↗
[Early amnion rupture as a cause of multiple congenital abnormalities in the newborn infant].
We describe two children with congenital deformities due to the early amniotic rupture syndrome. One child who had an amniotic band around the upper arm suffered from a distal nerve lesion. This was relieved following surgery. The second child died shortly after birth of multiple congenital malformations. The most usual findings in this syndrome are constriction of a limb by an amniotic band, scoliosis or syndactyly due to oligohydramnion with compression. We discuss one accepted hypothesis (subscribed by an experimental animal study) of the aetiology of the early amniotic rupture syndrome.
Abnormalities, Multiple↗
Cardiomyopathy associated with carnitine loss in kidneys and small intestine.
A boy was first seen at the age of 1 year on account of congestive cardiomyopathy. Growth and development had been normal. Total plasma carnitine was extremely low (1.8 mumol/l; normal range: 25-64 mumol/l). No hypoglycaemia, lactic acidaemia or dicarboxylic aciduria were found. Other laboratory findings were unremarkable except for a slight deficiency in iron, vitamin D and vitamin E. Total muscle carnitine was 1.5% of normal; however, no signs or symptoms of myopathy could be detected. After carnitine loading, liver carnitine increased to 24% of normal. Isolated muscle mitochondria showed decreased oxidative capacity with all substrates tested. Stimulation of O2 uptake by adenosine diphosphate (ADP) was decreased. After loading with both intravenous and oral carnitine, there was a rise in plasma carnitine and a rapid loss in the urine and the faeces. These findings suggest a defect in the brush border carnitine transport system of the kidneys and of the small intestine. Renal clearance of carnitine was abnormally high. Therapy with 1 g oral L-carnitine/kg per day was instituted without any problems and the cardiac disease resolved within 3 months. The parents and the patient's five sibs also had low plasma carnitine but displayed no cardiomyopathy.
Cardiomyopathies↗
[An adolescent with paroxysmal nocturnal hemoglobinuria].
Prompted by the case history of a 17 year old girl with anaemia, mononucleosis infectiosa and abdominal pain, paroxysmal nocturnal haemoglobinuria (PNH) is described. After a mononucleosis infectiosa infection she developed many complications of which the most prominent were hemolysis and thrombosis. Severe abdominal pain and episodic bowel obstruction occurred as a result of micro-infarction of the mesentery; bone marrow aplasia and lysis of platelets resulted in progressive thrombopenia. Pathogenesis and therapeutical possibilities are discussed. Coexistence of a necrotising enterocolitis with rectovaginal fistula, a heart infarction and the striking weight loss and hyponatremia during exacerbations, as seen in our patient, have not previously been described in PNH.
Adolescent↗
[Beware of anorexia non-nervosa].
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Adolescent↗