Another unusual type of citric acid cycle enzyme in Helicobacter pylori: the malate:quinone oxidoreductase.

The only enzyme of the citric acid cycle for which no open reading frame (ORF) was found in the Helicobacter pylori genome is the NAD-dependent malate dehydrogenase. Here, it is shown that in this organism the oxidation of malate to oxaloacetate is catalyzed by a malate:quinone oxidoreductase (MQO). This flavin adenine dinucleotide-dependent membrane-associated enzyme donates electrons to quinones of the electron transfer chain. Similar to succinate dehydrogenase, it is part of both the electron transfer chain and the citric acid cycle. MQO activity was demonstrated in isolated membranes of H. pylori. The enzyme is encoded by the ORF HP0086, which is shown by the fact that expression of the HP0086 sequence from a plasmid induces high MQO activity in mqo deletion mutants of Escherichia coli or Corynebacterium glutamicum. Furthermore, this plasmid was able to complement the phenotype of the C. glutamicum mqo deletion mutant. Interestingly, the protein predicted to be encoded by this ORF is only distantly related to known or postulated MQO sequences from other bacteria. The presence of an MQO shown here and the previously demonstrated presence of a 2-ketoglutarate:ferredoxin oxidoreductase and a succinyl-coenzyme A (CoA):acetoacetyl-CoA transferase indicate that H. pylori possesses a complete citric acid cycle, but one which deviates from the standard textbook example in three steps.

Early indicators for the risk of atherogenesis. A field test of a new methodology on kindergarten children in Düsseldorf.

Parameters related to the risk of atherogenesis in adults were investigated in kindergarten children living in an industrial city. Height, weight and blood pressure were measured and capillary blood obtained. This study is a field test of methods for the analysis of 11 metabolic variables in capillary serum [glucose (GLUC), uric acid (UA), total, free and esterified cholesterol (TC, C, CE), triacylglycerols (TG), phosphatidylethanolamine (PE), phosphatidylcholine (PC); beta-, pre-beta- and alpha-lipoproteins (LPs)]. For lipid and LP analysis, new micro- and ultramicroprocedures were used, which have proved to be adequate for large-scale studies outside the clinic, including young children. Among 497 German children, a reference group, an overweight group and a socially underprivileged group were distinguished. In the reference group, several sub-groups with parameters lying in the tails of the concentration distributions were considered separately, thus providing specific metabolic patterns for these groups and, also, for any individual child. The children in the overweight group exhibited significantly reduced TC and beta-LP levels. In socially underprivileged children with anthropometric data within the normal range, a reduction of several blood constituents was seen: GLUC, TG, TC, PC, pre-beta- and alpha-LP; the PC: PE ratio was diminished. The beta: alpha-LP ratio in these children was moderately increased. This effect was more pronounced in growth-retarded children, who also showed negative correlation of TG: alpha-LP.

On the composition of capillary and venous blood serum.

The concentrations of various clinical-chemical substances in the capillary and venous blood serum of apparently healthy adults (20-30 yr) were examined in the fasting state. Total protein, bilirubin, calcium, sodium and chloride concentrations were significantly lower (less than or equal to 5%) in capillary than in venous serum. In non-hemolytic capillary sera, the concentration of potassium was nearly the same as in venous samples. Inorganic phosphorus and urea concentrations were identical in both specimens. There was a tendency for glucose concentrations to be higher in capillary than in venous serum. It is concluded that capillary and venous blood serum can be used interchangeably only for certain purposes. It should be emphasized that these results are valid for apparently healthy adults in the fasting state; other population samples remain to be investigated.

[Creatine kinase "NAC-activated": reference values for children (author's transl)]. / Creatinkinase "NAC-aktiviert": Referenzwerte bei Kindern.

Reference values for 327 children aged between 1 day and 15 years are given for the revised standard method for the determination of serum creatine kinase (CK) activity by activation with N-acetylcysteine (NAC). No sex-dependence could be observed, but CK activity was found to vary markedly with age. The following values are suggested as upper limits of the reference ranges for measurements at 25 degrees C: neonates: 1-3 days: less than or equal to 370 U/l, 4-10 days: less than or equal to 200 U/l, 11-31 days: less than or equal to 100 U/l; children (2 months-15 years): less than or equal to 90 U/l.

Differences in lipid and lipoprotein concentrations of capillary and venous blood samples.

The concentrations of lipids and lipoproteins measured in capillary blood serum taken from young adults were significantly lower than in venous blood, although they correlated satisfactorily. These differences may reflect differences in the morphological and hemodynamic conditions existing either in large veins or in the peripheral circulatory system. It was concluded that venous and capillary blood serum cannot be used interchangeably for these estimations.