Quantification of Dihydroxyacetone Phosphate (DHAP) in Human Red Blood Cells by HPLC-TripleTOF 5600™ Mass Spectrometer.

Triosephosphate isomerase (TPI) is a glycolytic enzyme which catalyzes the interconversion between glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP). TPI deficiency results in accumulation of DHAP in human red blood cells and other tissues. The disease is characterized by congenital hemolytic anemia, and progressive neuromuscular dysfunction. The laboratory diagnosis is generally made by measurement of TPI activity in RBCs. Measurement of DHAP can be useful in further confirmation and follow-up of the disease. We developed HPLC/TOF-MS method for quantitation of DHAP in RBCs. The method involves simple protein precipitation, reverse phase C8 column chromatography, ion pairing with tributylamine, and long run time of 50 min to separate the two isomers (G3P and DHAP).

Rhizomelic chondrodysplasia punctata-like phenotype in a newborn male with normal peroxisomal function.

A newborn male with the characteristic phenotype of classic rhizomelic chondrodysplasia punctata (RCDP) and with the usual and severe radiographic skeletal abnormalities is described. The parents were young, healthy, and not consanguineous; the mother had not used licit or illicit drugs, alcohol, or tobacco during pregnancy and had not been exposed to radiation or teratogenic chemicals. The clinical phenotype led us to study peroxisomal function. Plasmalogen content in erythrocytes, membrane, and fibroblasts; dihydroxyacetone phosphate acyltransferase (DHAP-AT), alkyldehydroxyaceton phosphate synthetase (a gift from Professor Henk van der Boch, Utrech) in fibroblasts; and phytanic and pristanic acids in plasma showed normal values. Immunocytofluorescence study with antibodies against peroxisomal membrane showed normal organelles. We found no reference in the literature of a case of RCDP with normal peroxisomal functions, but non-CDP has been described with peroxisomal dysfunction. This phenotype (RCDP) may be due to other metabolic error.

Hereditary deficiency of lactate dehydrogenase H-subunit.

We report herein the fifth family of hereditary deficiency of lactate dehydrogenase (LDH) H-subunit with an autosomal recessive inheritance including two cases of complete deficiency. Their LDH activities were low both in the serum and in the red blood cells (RBC). Electrophoretic analysis revealed that the patients with the complete deficiency had only the LDH5 isozyme. The complete deficiency was associated with marked elevation of fructose-1, 6-diphosphate (FDP) and dihydroxyacetonephosphate (DHAP) and a less marked rise in glyceraldehyde-3-phosphate (GA3P) among glycolytic intermediates in the RBC. Furthermore, hemolysis was observed in the present cases, but this finding was not included in the other reports.

Hereditary triosephosphate isomerase (TPI) deficiency: two severely affected brothers one with and one without neurological symptoms.

A 13-year-old Hungarian boy (B.J.Jr.) with congenital haemolytic anaemia (CHA) and hyperkinetic torsion dyskinesia was found to have severe triose-phosphate isomerase (TPI) deficiency. One of his two brothers (A.J.), a 23-year-old amateur wrestler, has CHA as well, but no neurological symptoms. Both have less than 10% TPI activity and a highly increased dihydroxyacetone phosphate (DHAP) level in their red blood cells. Their TPI had a slow electrophoretic mobility and was heat unstable. Both parents and a third brother are healthy heterozygous carriers of the defect. A.J. represents a unique phenotype from the point of view that all published "homozygotes" had severe neurological alterations from infancy or early childhood except one infant who died at 11 months, probably too young for neurological symptoms to be noted. In contrast to the two affected Hungarian brothers all but one "homozygote" has died before the age of 6 years. The striking difference in the clinical course of the defect between the two brothers with the same severe red blood cell enzyme deficiency may originate from unusual differences between two double heterozygous brothers resulting inter alia in different levels of TPI expression in various tissues. Significantly lower TPI activities were found in both the T- and B-cells of the propositus as compared to the respective cells of the neurologically symptom-free brother.

Lead poisoning: clinical, biochemical, and haematological aspects of a recent outbreak.

The clinical, biochemical, and haematological aspects of a recent outbreak of lead poisoning, in which exposure was related to the oxyacetylene cutting of red lead painted ironwork, were investigated. Initial suspicion was raised when a blood film showed punctate basophilia which remains a simple and useful method of picking up lead toxicity. Estimations of blood lead concentration and conventional laboratory data confirmed the diagnosis. Although there was prominent punctate basophilia, spectrophotometric analysis showed only negligible accumulation of pyrimidine-5'-nucleotides despite severe suppression of pyrimidine-5'-nucleotidase activity. The pattern of the red cell glycolytic intermediates, investigated for the first time, suggested that lead may also affect glycolysis at the hexokinase step. Once the diagnosis was made intravenous chelation treatment was begun with a rapid improvement in symptoms. Long term follow up is required to assess any sequelae of intoxication. These cases emphasise the classic features of lead poisoning, and despite the currently available diagnostic tests, lead intoxication may still go unrecognised unless a thorough occupational history is taken.

Prenatal diagnosis of a red-cell enzymopathy: triose phosphate isomerase deficiency.

A child with triose phosphate isomerase deficiency was born to nonconsanguineous parents, and died at 13 months of age. The parents were both found to be heterozygous for this enzyme deficiency. At a subsequent pregnancy, analysis of fetal red blood cells obtained by cordocentesis at 19 weeks' gestation enabled prenatal diagnosis of the heterozygous state. This technique may allow diagnosis of other red-cell enzymopathies during the second trimester.

Red cell metabolic alterations in postnatal life in term infants: glycolytic intermediates and adenosine triphosphate.

Red cell glycolytic intermediates and adenosinetriphosphate were evaluated in term infants from birth to on year of age and compared to values obtained from normal adults and subjects wit a population of a similar mean cell age. The concentration of glycolytic intermediates, with the exception of phosphoenolypyruvate were elevated at birth when compared to normal subjects, consistent with a young mean red cell population. The mean levels of red cell glucose-6-phosphate, fructose-6-phosphate, and "total triose phosphate" were elevated on days 1 and 4 of life when compared to both red cells from normal adults and subjects with a similar young mean red cell age. Glucose-6-phosphate steadily increased in concentration, peaked at 3 to 4 wk of age, and then progressively decreased in value. Total triose phosphate declined to a mildly elevated concentration by 3 to 4 wk of age. The mean concentrations of 2,3-diphosphoglycerate and adenosine triphosphate were normal on day 1, increased on day 4, and then declined by 3 to 4 wk to normal values, until 5 to 6 months when both increased. The mean phosphoenolpyruvate concentration was decreased on day 1 of age when compared to red cells of a similar mean age, but this decrease was not significant (P greater than 0.05). The mean concentrations of 3-phosphoglycerate increased at 3 to 4 wk of age and remained elevated for cell age at 11 to 12 months but this increase was no statistically significant (P greater than 0.05). 3-Phosphoglycerate levels did not change significantly throughout the first year of life. At one year of age, all red glycolytic intermediates and adenosine triphosphate were elevated when compared to red cells from normal adults, but were comparable to those observed in subjects with a red cell population of a similar mean cell age, consistent with the persistence of a young red cell population throughout the first year of life.

A path analysis of the causal relationships between red cell glycolytic intermediates, ADP and ATP in sickle cell anemia.

The statistical relationships among the glycolytic intermediates (GI)) of the Embden-Meyerhof pathway, adenine nucleotides (ANs) and various hematological measures were estimated for 34 sickle cell anemia patients. Heterogeneity in linear and quadratic regressions of hemoglobin and hematocrit, both singly and jointly, on the GI and AN variables implied 1) that any single formula to standardize optical density measures of the GIs and ANs on a per gram hemoglobin or per liter cell water basis would not uniformly remove hemoglobin and hematocrit effects: 2) that ignoring significant hematological effects could bias the estimates of correlation among GIs and ANs; and 3) that hemoglobin and hematocrit measures do not reflect the same source of variability. The correlations among the GIs and ANs, after adjustment for hematological variability, were analyzed by path analysis to determine which of five proposed path models for cause and effect relationships were compatible with the data. AMP had a greater influence on ADP (coefficient of determination (CD) = 23%) than all the GIs together, while G6P and ADP influenced ATP variability the most (CD = 33% and 12%). The contributions of unknown factors to ADP and ATP variability were large for all models (CD = 56--77%) possibly due to stress of sickle cell disease. The path model with AMP and the four GIs (G6P, F6P, FDP, DHAP) influencing ADP variation, and the same GIs and ADP influencing ATP was the model most compatible with the data.

[The effect of inosine, inorganic phosphates and pyruvate on erythrocyte glycolysis metabolites under conditions of preservation]. / Der Einfluss von Inosin, anorganischem Phosphat und Pyruvat auf die Glykolysematabolite in Erythrozyten unter Konservierungsbedingungen

Human erythrocytes were stored as resuspensions in solutions containing citrate (Z), inosine + citrate (I), inosine + phosphate (IP), and inosine + phosphate + pyruvate (IPP). The storage was made at + 4 degrees C for 6 weeks; the initial pH-value amounted to 7.4 at + 4 degrees C. The cellular concentrations of 2.3 DPG, ATP, G6P, FDP and DOAP + GAP were determined. The following results were obtained: 1. During the storage in stored Z-blood the 2.3 DPG concentration will fall below 10% of its initial value; it will remain nearly unchanged in stored I-blood and will increase to 170% in stored IP-blood, to 270% of its initial value in stored IPP-blood. 2. The ATP concentration of cells will fall to about 50% of its initial value at the beginning of the storage of all stored blood. After that it will only increase to about 80% of its initial value in stored IP- and IPP-blood. 3. During the storage the G6P concentration will increase to the highest degree in stored IPP-blood and if high pyruvate concentrations are not present, it will have a reciprocal behaviour towards the FDP and triosephosphate level. The results were discussed in view of the regulation of glycolysis under storage conditions.