Abstract:  Malignant atrophic papulosis (Kohlmeier-Degos disease) is reported for the first time with pathologic verification of central nervous system involvement in a child. The disease began in infancy with rare recurring skin lesions; the child died at the age of 7, after progressive neurologic deterioration. Diagnosis was suspected clinically and confirmed by biopsy of a typical skin lesion. Recognition of this disorder by its dermatologic manifestations may obviate invasive diagnostic procedures.

Abstract:  Lipoamide dehydrogenase (LAD) kinetic values, Km and Vmax, were normal in 11 patients with Friedreich ataxia. Fibroblast activities of the pyruvate and alpha-ketoglutarate dehydrogenase complex, and LAD activities, were also normal. There was no reduction in oxidative decarboxylation of pyruvate, alpha-ketoglutarate, or several other substrates in intact fibroblasts. Methodologic differences may account for differences of opinion about putative abnormalities of the alpha-ketoacid dehydrogenase complexes.

Abstract:  Propionate inhibits oxygen consumption by rat liver mitochondria when glutamate, alpha-ketaglutarate, and succinate are substrates. Carnitine prevents this effect. The pattern of inhibition of 14CO2 release from metabolic intermediates indicates citric acid cycle inhibition between succinate:coenzyme A (CoA) ligase (GDP) and malate dehydrogenase. Propionyl CoA is synthesized from propionate in mitochondria. Propionyl CoA is a potent inhibitor of succinate:CoA ligase with positive cooperativity and half half-maximal inhibition at 2 X 10(-4) M propionyl CoA.

Abstract:  Ornithine metabolism is coupled to oxidative phosphorylation in isolated rat liver mitochondria. The pathway involving ornithine: alpha-ketoglutarate transaminase (OKT), glutamic semialdehyde dehydrogenase (GSDH), and glutamate dehydrogenase (GDH) with cycling of alpha-ketoglutarate-glutamate at the OKT reaction appears to be involved. Ornithine may be utilized by this pathway to sustain ATP levels during mitochondrial energy-deficiency states with resultant decreased urea-cycle flux and increased ammonia production. This pathophysiologic mechanism suggests that hyperammonemia is a consequence of an energy-deficiency state. Therapy directed toward alleviating the energy-deficiency state may be more beneficial than efforts to reduce ammonia levels.

Abstract:  Sodium valproate (VP) inhibited oxidative phosphorylation in isolated rat liver mitochondria. State 3 rates of oxygen consumption with glutamate as substrate were 80% of control values at a low VP concentration (24 microM). At 240 microM, there was more than 50% inhibition of glutamate and alpha-ketoglutarate state 3 rates. Succinate state 3 rates were 80% of control values, and uncoupling was noted at 2400 microM VP. These VP effects were similar to those of propionate and isovalerate, suggesting a common mechanism of toxicity. Inhibition of mitochondrial oxidative phosphorylation may explain why VP intoxication causes a hepatocerebral disorder that resembles Reye syndrome.

Abstract:  Severe immunosuppression with prednisone and cyclophosphamide failed to prevent neurological progression in a patient with adrenoleukodystrophy.

Abstract:  Polarographic assays of oxidative phosphorylation in muscle mitochondria indicated abnormal pyruvate-malate metabolism in Friedreich ataxia (FA). Pursuing this clue, more specific assays were performed. Mitochondrial malic enzyme (MEm; malate: NADP+ oxidoreductase) specific activity was 10% of controls in fibroblasts from eight FA patients (p less than 0.0001). Cytosolic malic enzyme was modestly increased in FA fibroblasts. Mitochondrial and cytosolic malate dehydrogenase and aspartate aminotransferase, and malate transport on the dicarboxylate and alpha-ketoglutarate carriers were normal in fibroblasts or leukocytes. MEm activity is normally highest in the nervous system and heart is important in regulating carbohydrate metabolism. MEm deficiency could cause FA; further studies are required to substantiate this hypothesis.

Abstract:  The protonmotive force (delta p) of muscle mitochondria was measured by estimating the distribution of 14C-labeled TPMP (trimethylphenylphosphonium iodide) and 14C-labeled acetate across the inner membrane of muscle mitochondria. The matrix volume was simultaneously determined using 3H-labeled H2O and 3H-labeled mannitol and repeated drying to distinguish the label in these 2 compounds. Rapid separation of mitochondria from the incubation medium by centrifugation through silicone oil avoids the problems of potential anaerobic conditions associated with conventional centrifugation and large volumes of trapped media associated with filtration. The value for delta p (mean +/- SD) was 192+/- 26 mV in 30 determinations with rat muscle mitochondria during state 4. Measurement of oxygen consumption allowed calculation of membrane conductance (Cm,H+) which was 0.49 +/- 0.18 nmol of H+/min/mg protein/mV. The values for delta p and Cm,H+ are reported for a variety of experimental conditions and are consistent with Mitchell's chemiosmotic theory. Biopsy specimens obtained from human muscle gave state-4 delta p values of 197+/- 30 mV (n =5) and Cm,H+ values of 0.52 +/- 0.12 nmol of H+/min/mg/mV (n = 4). This delta p assay is the first described for coupled mammalian muscle mitochondria and will be useful in assessing membrane function.

Abstract:  Octanoate increased state 3 and state 4 respiration in rat liver mitochondria. The respiratory control rates decreased because state 4 was disproportionately affected. The ADP:O ratio was not affected. Octanoate produced a fall in the protonmotive force (delta p) of 30 mV during state 3 and state 4. The mitochondrial inner membrane proton conductance (Cm,H+) increased twofold during state 4. Similar effects were observed in polarographic assays of brain mitochondria, but measurements of delta p and Cm,H+ were not possible. Octanoate produces loose coupling in isolated mitochondria. This effect may play a role in the pathogenesis of Reye's syndrome.

Abstract:  Friedreich's disease (FD) obligate heterozygotes have reduced mitochondrial malic enzyme (MEm) activity in cultured fibroblasts. This indicates that the MEm deficiency in homozygous affected patients is genetically determined. Heterozygote MEm activity was only 20% of the control mean activity, lower than the 50% expected in an autosomal-recessive disorder. This may result from negative interactions between mutant and normal subunits in the tetrameric enzyme. These data support the idea that MEm deficiency causes FD, but further studies are required to prove this hypothesis.

Abstract:  Thiamine deficiency causes Wernicke's encephalopathy, although the precise mechanism is unknown. We used a low-thiamine diet in conjunction with a thiamine analog, pyrithiamine, as a model of severe thiamine deficiency in rats. We investigated the function of intact, coupled mitochondria isolated from both brain and liver. State 4 respiration did not change in the thiamine-deficient animals. Brain state 3 rates fell in thiamine-deficient animals when pyruvate/malate, alpha-ketoglutarate, or glutamate were used as substrate. Liver state 3 rates were depressed only when pyruvate/malate was substrate. Activities of brain and liver pyruvate dehydrogenase complex and alpha-ketoglutarate dehydrogenase complex were depressed in the thiamine-deficient group. We conclude that the mitochondrial abnormalities resulting from thiamine deficiency are secondary to depression of thiamine-mediated enzyme activity, rather than from a putative role of thiamine in chemiosmotic coupling, and that the resulting abnormalities in ATP synthesis and perhaps in glutamate catabolism result in the irreversible neurologic defect seen in this disease.

Abstract:  A glass micro-chamber which allows polarographic assay in a volume of 180 microliter is described. The conical shape of this chamber allows efficient mixing with a Teflon magnetic flea. This chamber facilitates the study of the small quantities of mitochondria obtained from human tissue biopsies or animal sources. The polarographic assay of mouse liver mitochondria is described.

Abstract:  An 8-month-old boy with severe lactic acidosis was found to have lipoamide dehydrogenase deficiency. Treatment with thiamine, biotin, bicarbonate, protein restriction, and ketogenic diet failed to alleviate the lactic acidosis. Oral administration of lipoic acid 25 to 50 mg/kg produced dramatic improvement in lactic and pyruvic acidemia, which has continued for 2 years and which has been accompanied by clinical improvement.

Abstract:  Bilirubin accumulates within, and induces loose coupling in, rat liver mitochondria. This state, characterized by a normal protonmotive force, but increased oxygen consumption and inner membrane conductance, could impair cellular energy metabolism. Loose coupling is observed at bilirubin concentrations (12-24 microM) attained in tissues of kernicteric animals.

Abstract:  Experimental intraventricular hemorrhage was produced by injection of autologous fresh blood (0.25 ml/kg) or artificial CSF into the right lateral ventricle of 24 dogs. A transient ventricular fluid acidosis (pH drop to 7.09) was accompanied by increased lactate, pyruvate, ammonia, and Pco2, and decreased bicarbonate and glucose. High lactate/pyruvate ratios were the most persistent abnormality. The control group, which received intraventricular artificial CSF, developed minimal ventricular fluid acidosis (pH 7.26). Lumbar CSF and venous blood acid-base parameters did not change. Simultaneous cisternal samples obtained from some of the animals reflected similar metabolic abnormalities of lesser magnitude. Intraventricular injection of sodium bicarbonate normalized the pH in four animals.

Abstract:  Relative carnitine deficiency is important in the pathophysiology of several disorders, including Reye's syndrome and organic acidemias. In acute clinical crises, carnitine serves as a "buffer," trapping toxic acyl compounds. Mitochondrial failure develops in carnitine deficiency when there is insufficient tissue carnitine available to buffer toxic acyl-CoA metabolites. Toxic levels of acyl-CoA impair the citrate cycle, gluconeogenesis, the urea cycle, and fatty-acid oxidation. Carnitine replacement therapy is safe and induces excretion of toxic acyl groups in the urine.

Abstract:  Clinical, biochemical, and genetic studies have brought clarity to many issues concerning the inherited ataxias. The classification, diagnosis, and therapy of hereditary ataxias are now better understood although many questions remain. Basic defects are identified in some disorders.

Abstract:  Diagnosis and classification of the inherited ataxias are reviewed with emphasis on recognizing treatable disorders. Even when basic defects are untreatable, many complications of the degenerative process are amenable to therapy.

Abstract:  Although antiepileptic medications may play a role in fetal malformations, this risk appears no greater than the risk associated with either the seizures themselves or a change in medication during pregnancy. In general, the number and the dose of antiepileptic medications should be minimized during pregnancy. Potential complications during the pregnancy must be anticipated. Drug levels must be monitored. Because the fetus is at a somewhat higher risk, ultrasound studies may be useful in monitoring the pregnancy. Delivery should take place in a center where appropriate facilities are available if intervention is required during labor or if the baby is malformed. Both the infant and the mother should be monitored closely after the delivery.

Abstract:  A 30-year-old woman was thought to have Friedreich's disease because of progressive ataxia, dysarthria, and titubation from age 3 years. Her diet was normal, and there were neither symptoms nor laboratory evidence of liver disease or fat malabsorption. Serum vitamin E content and the ratio of serum vitamin E to total serum lipid were very low, but serum vitamin A, cholylglycine, and lipid levels were normal, as was an oral vitamin E tolerance test. Muscle biopsy showed the lysosomal inclusions of vitamin E deficiency. Mitochondria had normal oxidative phosphorylation using polarographic assays. The cause of her vitamin E deficiency was unknown.

Abstract:  We observed four young adults, including three siblings, with a progressive neurologic disorder that developed over the first two decades. Electrophysiologic studies revealed mildly delayed nerve conduction, decreased amplitudes of sensory action potentials, and sensory delay in the posterior columns. Known causes of similar neurologic disorders were excluded. Although vitamin E deficiency was well documented, intestinal absorption and plasma lipoprotein transport of vitamin E were normal. Incubation studies in vitro failed to identify a plasma factor causing destruction of circulating vitamin E. There was no clinical or laboratory evidence of steatorrhea caused by gastrointestinal, hepatic, or pancreatic disease. Plasma lipoproteins, apolipoprotein B, and adipose tissue fatty acid composition were normal. Oral vitamin E therapy restored serum levels to normal and caused neurologic improvement in two patients. We postulate that an inherited defect in hepatocyte secretion of vitamin E into lipoproteins may account for this disorder, which occurs in sporadic cases as well as in siblings.

Abstract:  Propionic acidemia occasionally produces a toxic encephalopathy resembling Reye's syndrome, indicating disruption of mitochondrial metabolism. Liver mitochondria respiratory control ratios were reduced 46% by 5 mM propionate; inhibition correlated with matrix propionyl-CoA levels. L-Malate prevented the toxic effect of propionate and reduced the propionyl-CoA matrix concentration by 62%. The beneficial effect of L-malate is apparently due to stimulation of succinate efflux because the effect is blocked by benzylmalonate, an inhibitor of the dicarboxylate carrier. Matrix concentration of label from [1-14C]propionate was not affected by L-malate and/or benzylmalonate. L-Malate may be useful in the treatment of patients with propionic acidemia.

Abstract:  Combined 3-methylglutaconic and 3-methylglutaric aciduria, one of the more common urinary organic acid abnormalities, has been observed in at least three clinical syndromes. We studied an additional seven patients with 3-methylglutaconic aciduria, four of whom were best categorized as having the type II syndrome, two as having an "unspecified" syndrome, and one who may have had a primary urea cycle defect. In cultured cells and autopsy tissues derived from patients with the type II and unspecified syndromes, we were unsuccessful in identifying a defect in the leucine degradative pathway distal to 3-methylcrotonyl-coenzyme A carboxylase and in the cholesterol biosynthetic pathway between 3-hydroxy-3-methylglutaryl-coenzyme A reductase and diphosphomevalonate decarboxylase. Further assessment of the cholesterol biosynthetic pathway in several patients with one of the two types of disease also provided no defined abnormality. The primary metabolic defects in the type II and unspecified syndromes remain undefined.

Abstract:  Propionic acidemia occasionally produces a toxic encephalopathy resembling Reye syndrome, indicating disruption of mitochondrial metabolism. Understanding the mitochondrial effect of propionate might clarify the pathophysiology. Liver mitochondria are inhibited by propionate (5 mM) while muscle mitochondria are not. Preincubation is required to inhibit liver mitochondria, suggesting that propionate is metabolized to propionyl CoA. Liver and skeletal muscle mitochondria incubated with [1-14C]propionate contain similar quantities of matrix isotope and release comparable [14C]CO2. However, only liver mitochondria accumulated significant propionyl CoA, which was largely (68%) synthesized from propionate. Carnitine reduced the level of liver matrix propionyl CoA. Inhibition of respiratory control ratios by propionate correlated with propionyl CoA levels. These results support the hypothesis that acyl CoA esters are toxic and that carnitine exerts its protective effect by converting acyl CoA esters to acylcarnitine esters.

Abstract:  We describe the clinical features of 25 cases of Werdnig Hoffman's disease (spinal muscular atrophy (SMA) type I) seen propectively over a two-year period at the King Fahd Hospital of the University (KFHU), Al-Khobar. The hospital incidence rate was 1.93 per 1,000 live births (95% confidence limits, 0.80-3.06/1,000). The estimated prevalence rate for the community was 0.92/10,000 with 0.59-1.25 per 10,000 children as its 95% confidence limits. The male to female ratio was 2:3. Reduced fetal movements were reported by six mothers; 8 children (32%) had symptoms at birth, and 24 (96%) had symptoms by the time they were six months old. Other features apart from hypotonia, muscle weakness, and absent deep tendon reflexes included head lag with inability to achive head control at six months (88%), respiratory problems consisting of difficulty with breathing or frequent chest infections (44%), and difficulty with feeding (40%). Wasting with fisciculations of the tongue was seen in 64%. Death occurred within six months of presentation in 75% of the cases. The parents were consanguineous in 64% of the cases. This high consanguinity rate was probably the major cause for the high population prevalence rate.

Abstract:  An international perspective of Reye syndrome provides insights not noticeable with a parochial perspective. Sources of variation in Reye syndrome include geographic factors. The disappearance of Reye syndrome occurred globally, raising doubts about the importance of regional efforts to eliminate specific putative causes.

Abstract:  Familial vitamin E deficiency (AVED) causes ataxia and peripheral neuropathy that resembles Friedreich's ataxia. AVED is thought to be caused by a defect in the transport of vitamin E in liver cells, which is the probable function of alpha-tocopherol transfer protein (alphaTTP). We have cloned the cDNA and several genomic phage clones covering the entire human alphaTTP gene and determined the junctions between the five exons and four introns that composed the gene for human alphaTTP. Three mutations in three unrelated North American families with AVED were identified. Two mutations, 485delT and 513insTT, cause a frame shift and a premature stop codon and the third mutation 574G-->A would substitute Arg192 to His in alphaTTP. The 2 patients with a severe form of AVED were homozygous with 485delT and 513insTT, respectively, while the patient with a mild form of the disease was compound heterozygous with 513insTT and 574G-->A. These findings have identified the underlying genetic defect in AVED and have confirmed the role of alphaTTP in AVED.

Abstract:  Perinatal hypoxia-ischemia remains a significant cause of neonatal mortality and neurodevelopmental disability. Numerous lines of evidence indicate that cerebral ischemic insults disrupt normal respiratory activity in mitochondria. Carnitine (3-hydroxy-4-N-trimethylammonium-butyrate) has an essential role in fatty acid transport in the mitochondrion and in modulating potentially toxic acyl-CoA levels in the mitochondrial matrix. There are no naturally occurring esterases available to reduce the accumulation of acyl-CoA but this process can be overcome by exogenous carnitine. We used a newborn rat model of perinatal hypoxia-ischemia to test the hypothesis that treatment with l-carnitine would reduce the neuropathologic injury resulting from hypoxia-ischemia in the developing brain. We found that treatment with l-carnitine during hypoxia-ischemia reduces neurologic injury in the immature rat after both a 7- and 28-d recovery period. We saw no neuroprotective effect when l-carnitine was administered after hypoxia-ischemia. Treatment with d-carnitine resulted in an increase in mortality during hypoxia-ischemia. Carnitine is easy to administer, has low toxicity, and is routinely used in neonates as well as children with epilepsy, cardiomyopathy, and inborn errors of metabolism. l-Carnitine merits further investigation as a treatment modality for the asphyxiated newborn or as prophylaxis for the at-risk fetus or newborn.

Abstract:  BACKGROUND: Although many lines of evidence suggest an autoimmune etiology, the pathophysiology of opsoclonus-myoclonus syndrome (OMS) remains poorly understood and no immunologic abnormalities have correlated with neurologic severity. Conventional immunotherapies often do not prevent relapse or permanent sequelae. OBJECTIVE: To test the cellular immune hypothesis of OMS in a cross-sectional study and determine if CSF lymphocyte subset analysis provides biomarkers of disease activity. METHODS: The expression of lymphocyte surface antigens was investigated in CSF and blood of 36 children with OMS and 18 control subjects, using a comprehensive panel of monoclonal antibodies to adhesion and activation proteins in combination with anti-CD3 and anti-CD45 antibodies in four-color fluorescence-activated cell sorting. RESULTS: Although most children with OMS had normal CSF cell counts, they exhibited expansion of CD19+ B-cell (up to 29%) and gammadelta T-cell (up to 26%) subsets and a lower percentage of CD4+ T-cells and CD4/CD8 ratio, which persisted even years after disease onset and conventional treatments. The percentage of activated CSF T-cells was also higher. Abnormalities correlated with neurologic severity, as scored blinded from videotapes using a 12-item motor scale, and disease duration. No significant differences were found between tumor and no-tumor groups. In children with neuroblastoma, tumor resection or cancer chemotherapy did not alter immunologic abnormalities. CONCLUSIONS: CSF B- and T-cell recruitment is linked to neurologic signs in pediatric OMS, which may relate to relapses and disease progression.

Abstract:  We describe a 10-year-old immunocompetent male whose initial presentation was consistent with the diagnosis of acute disseminated encephalomyelitis. He relapsed 3 months later, with new neurologic signs and lymphadenopathy. T-cell lymphoma was diagnosed by lymph node and stereotaxic brain biopsy. This patient represents a rare report of T-cell lymphoma in an immunocompetent child presenting with central nervous system symptoms.