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Biomedical subjects

J Christodoulou

Publications and source records attributed to J Christodoulou.

At least 19 recordsLinked to original sources
PubMed1995

Peroxisomal assembly defects: clinical, pathologic, and biochemical findings in two patients in a newly identified complementation group.

We describe the clinical, pathologic, and biochemical findings for two peroxisome-deficient patients in a newly identified complementation group. Both patients had biochemical findings typical of patients with peroxisome biogenesis disorders. However, whereas one patient had the typical clinicopathologic features of Zellweger syndrome, the other patient's phenotype was atypical.

Catalase↗
PubMed1995

Neonatal onset of medium-chain acyl-coenzyme A dehydrogenase deficiency with confusing biochemical features.

A female neonate was seen because of shock, ketosis, and undetectable blood glucose. Initial urinary findings indicated the possibility of a defect of fatty acid beta-oxidation; subsequent studies showed that she had medium-chain acyl-coenzyme. A dehydrogenase deficiency. This case highlights the fact that the initial symptoms may occur in the first few days of life, and that the presence of ketosis does not exclude the possibility of a fatty acid oxidation defect; the profiles of urinary organic acids and acylglycines may not be characteristic at that time.

Acyl-CoA Dehydrogenase↗
PubMed1995

A mutation causing DHPR deficiency results in a frameshift and a secondary splicing defect.

In our analysis of mutations causing DHPR deficiency we identified a patient in whom there was an aberrant transcription pattern detected by PCR of DHPR cDNA. However, unlike the pattern observed as a result of most splicing mutations, there is some full length transcript. The mutation was located and is a single nucleotide deletion at position 570/571 of the DHPR cDNA sequence and results in a frameshift and premature termination after the addition of six amino acids. The mutation is present in a homozygous state in the patient and in a heterozygous state in both parents. The exon which is deleted at high frequency in the patient is the putative exon 4, which is remote from the mutation, and confirms our observation that exon 4 skipping is a relatively common event.

Base Sequence↗
PubMed1994

A new structural transition of serum albumin dependent on the state of Cys34. Detection by 1H-NMR spectroscopy.

1. Reactions of fatty-acid-free bovine serum albumin and recombinant human albumin with a range of antiarthritic gold(I) complexes [auranofin, deacetylated auranofin, triethylphosphinegold(I) chloride] and related thiols (thioglucose, tetraacetylthioglucose, glutathione, dithiothreitol) have been investigated using 1H-NMR spectroscopy. 2. In reactions of albumin with auranofin, tetraacetylthioglucose and dithiothreitol, release of cystine was detected, whereas for deacetylated auranofin, thioglucose and glutathione, mixed disulphides with cysteine were produced. It has been previously proposed that Cys34 of human and bovine serum albumins is partly blocked by disulphide formation with cysteine and glutathione. The above reactions lead to deblocking by thiol-disulphide interchange reactions. No release of glutathione from albumin was detected. 3. Changes in the His H epsilon 1 regions of the 1H-NMR spectra show that albumin exists in two structural forms dependent on whether the side-chain of Cys34 is a free thiolate, or blocked by gold(I)triethylphosphine, by disulphide formation with cysteine or by another form of oxidation. We propose that Cys34 is either in a buried or in an exposed environment; the possible molecular basis of the structural change is discussed. 4. The relationship between reactions at Cys34, cysteine release, and the observed structural transition are discussed in terms of chrysotherapy, albumin metabolism and the use of gold(I) as a heavy atom derivative in X-ray crystallographic studies of albumins.

Amino Acid Sequence↗
PubMed1994

Barth syndrome: clinical observations and genetic linkage studies.

Barth syndrome is an X-linked recessive condition characterized by skeletal myopathy, cardiomyopathy, proportionate short stature, and recurrent neutropenia, but with normal cognitive function. Some, but not all patients, exhibit carnitine deficiency and/or the presence of 3-methylglutaconic and ethylhydracylic acids in urine. Recently the mutation causing Barth syndrome was localised to the Xq28 region by linkage analysis. We report 6 cases of Barth syndrome from 4 families and highlight the fact that neuromuscular and cardiovascular symptoms and the severity of infections tend to improve with age, while short stature persists. Also previously unreported was myopathic facies and nasal quality to speech in our cases. The urinary organic acid abnormalities and plasma carnitine deficiency were inconsistent findings. We propose that they may be epiphenomena rather than indicators of the primary metabolic defect, and that the primary defect or defects in this disorder may lie in the mitochondrial electron transport chain.

Abnormalities, Multiple↗
PubMed1994

Malonic aciduria.

Three infants with malonic aciduria are reported, one of whom could be studied in detail. All children had severe and progressive encephalopathy with intermittent ketoacidosis and hypoglycemia. One infant died of cardiomyopathy. Biochemical studies revealed that one patient had neither malonyl-CoA decarboxylase nor glutaryl-CoA dehydrogenase deficiencies. This variant of malonic aciduria is different from that of four patients previously reported, both in its clinical and biochemical presentations. The biochemical pathology of this variant malonic aciduria is unknown.

Acidosis↗
PubMed1994

Hyperinsulinaemia in syndrome X: a marker of the syndrome?

BACKGROUND: Stimulated hyperinsulinaemia is observed in some patients with syndrome X, defined as angina, positive stress test and normal coronary arteriography, and may be involved in the pathogenesis of the syndrome. An increased sympathetic response to exercise may also be pathogenetically involved. However, the diagnostic value of hyperinsulinaemia as a marker of this syndrome has not been defined. METHODS: We determined blood glucose and immunoreactive insulin during fasting, at 60 and 120 min after a glucose load of 75g in 21 patients (eight men, 13 women, 53.9 +/- 7.1 years old) with syndrome X and in 21 healthy volunteers matched to the patients for age, sex and body mass index (eight men, 13 women, 51.6 +/- 9.3 years old). Insulin values were related to the rate-pressure product increase at first exercise stage. RESULTS: The glucose values as well as the insulin values during fasting were similar in syndrome X patients and in controls. However, significantly higher insulin values (mU/l) were observed at 60 (P < 0.01) and 120 min (P < 0.005) in syndrome X patients (median 75.5 and 52, range 43-290 and 6.1-212, respectively) than in controls (median 47.5 and 24.5, range 8-195.6 and 5.2-164, respectively). A considerable overlap of insulin values, however, was observed between the two groups, with abnormal values even during fasting. For a specificity of 95%, an abnormal insulin value had a sensitivity of between 19 and 24% and a diagnostic accuracy of 57-60%. A significant positive correlation was found between insulin levels after the glucose load and the rate-pressure product increment with exercise (60 min, r = 0.60; 120 min, r = 0.65). CONCLUSION: Hyperinsulinaemia may be pathogenetically involved in syndrome X patients, in close relation to the higher sympathetic drive that characterizes this syndrome. However, the wide range of insulin values, frequently overlapping with normal values, limits the usefulness of this abnormality as a marker of the syndrome.

Blood Glucose↗
PubMed1992

"Reducing body"-like inclusions in skeletal muscle in childhood-onset acid maltase deficiency.

Unusual inclusions with some of the features of "reducing bodies" were encountered in the skeletal muscle biopsy of a 2.5-year-old boy with childhood-onset acid maltase deficiency. The biopsy revealed a vacuolar myopathy with lysosomal storage of glycogen and eosinophilic refractile inclusions in myofibers, which appeared dark blue with the menadione-nitroblue tetrazolium reaction. The significance of the association of inclusions with reducing properties in the setting of acid maltase deficiency is discussed.

Child, Preschool↗
PubMed1992

Autopsy findings in two siblings with infantile Refsum disease.

Recognition of adrenal atrophy during a review of autopsy findings in two sisters who died at 8 months and 3 1/2 years prompted estimation of very long chain fatty acids, phytanic acid and pristanic acid on wet liver fixed in formalin for 12 years. These were shown to be markedly increased and defects in multiple peroxisomal functions and decrease in particulate catalase were shown in cultured fibroblasts, confirming an abnormality of peroxisomal biogenesis. The patients had presented with failure to thrive, recurrent diarrhoea and vomiting, poor mental development, retinal pigmentation, blindness and in the older patient deafness, with only mild dysmorphic features. Autopsy in the older patient showed adrenal atrophy, cirrhosis, and foamy histiocytes in multiple organs. The brain showed no demyelination, little cytoarchitectural abnormality, occasional perivascular histiocytes in the grey matter and meninges and prominent Purkinje cells in the molecular layer of the cerebellum. In the younger patient the changes were very subtle in spite of the marked clinical similarity. Despite the young age at death the clinicopathological features are most suggestive of infantile Refsum disease. In many situations anatomical pathology can be very useful in the recognition and study of peroxisomal disorders.

Adrenal Glands↗
PubMed1992

Heteroplasmic mtDNA mutation (T----G) at 8993 can cause Leigh disease when the percentage of abnormal mtDNA is high.

A female infant showing lacticacidemia, hypotonia, and neurodegenerative disease died at 7 mo of age. Autopsy revealed lesions typical of Leigh disease, both in the basal ganglia and in the brain stem. A maternal aunt and uncle died 1 year and 5 mo, respectively, after following a similar clinical course, while another uncle, presently 33 years of age, has retinitis pigmentosa and ataxia and is mentally retarded. PCR restriction-digest analysis of mtDNA isolated from the proband revealed a T-to-G change at position 8993, creating a new AvaI restriction site. The mutation present in the ATP 6 gene results in the substitution of an arginine residue for a leucine. The indexed patient had greater than 95% abnormal mtDNA in her skin fibroblasts, brain, kidney, and liver tissues, as measured by laser densitometry. The maternal aunt who died at age 1 year had greater than 95% abnormal mtDNA in her lymphoblasts. The uncle with retinitis pigmentosa had 78% and 79% abnormal mtDNA in his skin fibroblasts and lymphoblasts, respectively, while an asymptomatic maternal aunt and her son had no trace of this mutation. The mother of the index case had 71% and 39% abnormal mtDNA in her skin fibroblasts and lymphoblasts, respectively, showing that the heteroplasmy can be variable, on a tissue-specific basis, within one individual. This shows that mtDNA mutations at 8993 can produce the clinical phenotype of Leigh disease in addition to the phenotype of ataxia and retinitis pigmentosa described by Holt et al.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA, Mitochondrial↗
PubMed1990

Pathology of hepatic peroxisomes and mitochondria in patients with peroxisomal disorders.

The morphology of hepatic peroxisomes in five patients with metabolic disorders believed to be due to inherited defects of peroxisomal function or biogenesis is described. Electron microscopy and cytochemical staining for catalase were used to identify peroxisomes in two boys with infantile Refsum's disease (IRD), a girl with autopsy confirmed neonatal adrenoleukodystrophy (NALD), and two boys with pseudo-Zellweger syndrome (PZS). In the patients with IRD and NALD hepatic peroxisomes were significantly reduced in size and number and contained electron dense centres. In the liver of the patients with PZS the peroxisomes were enlarged. Morphologically abnormal peroxisomes were also detected in autopsy tissue from one boy with PZS using electron microscopy. Lamellar-lipid inclusions and mitochondria with crystalline inclusions and/or abnormal cristae are also described in two patients, one with IRD, the other with NALD.

Adrenoleukodystrophy↗
PubMed1989

Choanal atresia as a feature of ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome.

We report here a father and daughter with digital abnormalities, nasolacrimal duct obstruction, and variable alopecia. The father had a cleft lip and palate and the daughter had choanal atresia. We propose they both have the EEC syndrome and show the variable expressivity of this disorder. Choanal atresia has not been previously reported in this condition.

Choanal Atresia↗