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G Hug

Publications and source records attributed to G Hug.

At least 19 recordsLinked to original sources

Weanling and adult rats differ in fatty acid and carnitine metabolism during sepsis.

Increased oxidation of fat is an important host response to sepsis, and carnitine is essential for long-chain fatty acid oxidation. Because neonates have low levels of carnitine, their ability to respond to a septic insult may be impaired. The purpose of this study was to compare fatty acid and carnitine metabolism in septic weanling (60 to 85 g) and septic adult (285 to 310 g) rats. Sepsis was induced in weanling and adult male Sprague-Dawley rats by cecal ligation and puncture (CLP). The rats were killed 16 hours after CLP or sham operation, and serum glucose, lactate, beta-hydroxybutyrate, fatty acid, carnitine, liver fatty acid, and tissue carnitine levels were measured. The data suggest that during sepsis weanling rats may be more dependent on fatty acid oxidation than adult rats are, as evidenced by their elevated serum fatty acid and acylcarnitine levels, and relative hypoglycemia and hyperketonemia. In addition, although total serum carnitine levels were increased in both adult and weanling septic rats, tissue carnitine levels of weanling rats became significantly depleted during sepsis, unlike in adult rats. This study supports further investigation regarding the role of exogenous carnitine in newborn sepsis.

3-Hydroxybutyric Acid

Effects of parenteral L-carnitine supplementation on fat metabolism and nutrition in premature neonates.

The effects of parenteral L-carnitine supplementation on fat metabolism, nutrient intake, and plasma and erythrocyte carnitine concentrations were studied in 43 very low birth weight infants. Infants were randomly assigned to control or carnitine-supplemented (50 mumol/kg per day) groups within two weight categories: group 1, 750 to 1000 gm, and group 2, 1001 to 1500 gm. Plasma total, free, and acyl carnitine levels, erythrocyte carnitine levels, serum beta-hydroxybutyrate and triglyceride levels, and total fat intake were monitored weekly until 50% of total caloric intake was met enterally. Neonates receiving carnitine had higher plasma carnitine levels than control groups (total carnitine: group 1, 75.2 +/- 22.9 vs 9.6 +/- 2.7 mmol/ml; group 2, 61.6 +/- 31.2 vs 13.0 +/- 9.2 nmol/ml). Levels of beta-OH-butyrate decreased from baseline in control neonates (group 1, 0.12 +/- 0.06 to 0.03 +/- 0.02 mmol/L; group 2, 0.11 +/- 0.03 to 0.05 +/- 0.02 mmol/L); they remained unchanged in supplemented groups. Thus ketogenesis appeared less impaired in infants receiving supplements. Supplemented group 2 tolerated more fat than control group 2; triglyceride levels remained acceptable in all groups. Carnitine group 2 had greater weight gain than control group 2 during the first 2 weeks of life. We conclude that very low birth weight infants requiring prolonged parenteral nutrition have carnitine deficiency with impaired ketogenesis. Parenteral administration of carnitine appears to alleviate this metabolic disturbance.

Carnitine

Reduction of serum carnitine concentrations during anticonvulsant therapy with phenobarbital, valproic acid, phenytoin, and carbamazepine in children.

We determined four carnitine constituents (total and free carnitine and short- and long-chain fatty acid carnitine esters) in serum from 471 patients treated for convulsions with phenobarbital, valproic acid, phenytoin, and/or carbamazepine. The 471 patients were in eight treatment groups; four were treated with monotherapy and four with polytherapy. The means of all four carnitine constituents were significantly reduced in all treatment groups (except for free carnitine in four groups). Total carnitine was reduced by 23% to 48%, free carnitine by 9% to 45%, short-chain fatty acid carnitine by 46% to 64%, and long-chain fatty acid carnitine by 6% to 29%. Patient frequency of reduction for total carnitine was 20% of all patients (10% for free carnitine), 23% of patients receiving valproate (9% for free carnitine), 36% of those receiving phenobarbital (21% for free carnitine), 12% of those receiving phenytoin (8% for free carnitine), and 8% of those receiving carbamazepine (1% for free carnitine). Only for phenobarbital was there an inverse correlation between the serum concentration of the drug and that of carnitine concentration. One patient receiving carbamazepine had a 59% reduction in the total and a 65% reduction in the free carnitine concentration and a fivefold increase in long-chain fatty acid carnitine, values similar to those seen in neonatal lethal carnitine palmitoyl transferase II deficiency. It remains to be determined whether a reduction in serum carnitine values in patients receiving anticonvulsant therapy is of clinical consequence, whether the reduction is present in some patients before the start of therapy, when and by what mechanism carnitine levels may become reduced during therapy, and whether the reduction exists in the solid tissues of these patients.

Analysis of Variance

Simultaneous measurement of 25-hydroxy, 24,25-dihydroxy-, and 1,25-dihydroxyvitamin D without use of HPLC.

A procedure is described for measuring the concentration of three major vitamin D metabolites: 25(OH)D, 24,25(OH)2D and 1,25(OH)2D, in 0.5 ml serum. The analytes are extracted using C18, and separated using aminopropyl solid phase extraction cartridges. 25(OH)D is separated completely; less than or equal to 10% overlap is observed between the 24,25(OH)2D and the 1,25(OH)2D fractions, and this overlap did not interfere in subsequent competitive radioligand assay. Coefficient of variation (SEM/mean x 100%) is intra-assay (n = 10) 5.8, 3.1, 5.2%, and inter-assay (n = 5) 10.1, 8.7 and 6.4%, respectively. Recoveries of the three analytes added to a single specimen are 103, 95 and 111%, respectively. One technician can extract and fractionate up to 24 specimens in one day, ready for HPLC or direct estimation.

24,25-Dihydroxyvitamin D 3

Hypercalciuria with Bartter syndrome: evidence for an abnormality of vitamin D metabolism.

Some children with Bartter syndrome have hypercalciuria. To determine the mechanism for this phenomenon, we studied tubular function and calcium metabolism in six such children. All patients had hypokalemic alkalosis, normotension, hyperreninemia, growth retardation, low fractional distal chloride reabsorption (4/5), and elevated urinary prostaglandin E2 excretion (5/6). In addition, all had hypercalciuria (urinary calcium 6.5 to 25.0 mg/kg/day), with evidence of nephrocalcinosis in five. None, however, had evidence of rickets or hyperparathyroidism. There was a marked elevation in the serum concentration of 1,25-dihydroxyvitamin D in all, and four patients had a response to oral calcium loading suggestive of absorptive hypercalciuria. Five children have had long-term therapy with indomethacin. They have had improvement in hypokalemia and reduced urinary prostaglandin E2 excretion as well as reductions in the serum concentration of 1,25-dihydroxyvitamin D and in urinary calcium excretion. These data suggest that hypercalciuria in some children with Bartter syndrome is associated with an excess of 1,25-dihydroxyvitamin D. The improvement in hypercalciuria with prostaglandin synthesis inhibition may result in part from correction of this vitamin D abnormality.

Bartter Syndrome

Fetal mucolipidosis II (I-cell disease): radiologic and pathologic correlation.

A pregnant woman whose previous child had a diagnosis of I-cell disease was referred for evaluation of the fetus. Fluid obtained by amniocentesis and maternal serum showed abnormally increased levels of lysosomal enzymes suggesting that the fetus had I-cell disease. Sonography at 18 weeks showed abnormally short femurs and intrauterine growth retardation. The pregnancy was electively terminated at 19 weeks' gestation and the diagnosis was confirmed. Radiographs of the fetus demonstrated that the bony dysplasia is present early in fetal life with diffuse decrease in bone mineralization, a coarse, lacy, trabecular pattern, overall shortening and under-modelling of the long bones, subperiosteal bone deficiency in the diaphysis giving the appearance of periosteal new bone, hypoplasia of the anterior superior aspect of the upper lumbar vertebral bodies, broad ribs, abnormal pelvis with squared iliac wings and flattened acetabular roofs, and a small irregular calcaneal ossification center. There was good correlation between the radiographic findings and the microscopic findings in the bones. We observed deficient endosteal bone formation, small epiphyses, and poorly developed intervertebral discs. We speculate that this indicates impaired production of extra-cellular matrix by several different types of specialized mesenchymal cells. Abnormalities of transport of glycoproteins other than lysosomal enzymes or excess of extracellular acid hydrolases may be involved in the pathogenesis.

Bone and Bones

Glycogen accumulation in the pars recta of the proximal tubule in Fanconi syndrome.

We reviewed the renal pathology in 10 cases of renal Fanconi syndrome. Five cases showed the Armanni-Ebstein lesion, i.e., clear glycogen-filled cells limited to the pars recta of the proximal tubules. The 5 cases included 2 siblings with a unique syndrome characterized by death in infancy, severe Fanconi syndrome, severe rickets, carnitine deficiency, and atrophy of the exocrine pancreas. Two other siblings had glycogen storage disease type XI. One of 4 cases of putative tyrosinemia had the lesion. The ultrastructure was studied in 2 cases. The Armanni-Ebstein lesion in these cases was morphologically indistinguishable from that seen in diabetic patients dying after prolonged hyperglycemia. Glycosuria is the only common factor in both diabetic hyperglycemia and the varied proximal tubular diseases studied. The mechanism of the glycogen accumulation in this short parts recta segment of the proximal renal tubule was further investigated by reviewing the renal histology in cases of glycogen storage disease types I, II, III, and VIII. None showed the Armanni-Ebstein lesion, but type I showed glycogen deposition throughout the proximal tubule. Thus, the Armanni-Ebstein lesion is not the result of an enzymatic deficiency for glycogen synthesis in the convoluted tubules.

Adolescent

Morphologic characteristics of the placenta in glycogen storage disease type II (alpha-1,4-glucosidase deficiency).

Five placentas from infants with enzymatically diagnosed glycogen storage disease type II (three from midtrimester abortions, two from term deliveries) were studied by light and electron microscopy. On routine histologic examination with hematoxylin and eosin staining, storage cells were identifiable in the connective tissue of the amnion. These cells provide the means to diagnose this glycogen storage disease prior to the development of clinical symptoms. Electron microscopy, even in the midtrimester placenta, shows typical membrane-bound, glycogen-filled vacuoles in the villous endothelium and stromal cells. These vacuoles can provide confirmation of glycogen storage in cases of prenatal enzymatic diagnosis and therapeutic abortion.

Amnion