Quantitation of hemoglobin A1c: a rapid, automated precision-chromatography technique

Hemoglobin A1c is increased in patients with diabetes mellitus and its level reflects the status of blood glucose equilibrium over a period of several weeks. The practical use of its estimation was hampered by technical difficulties in investigating large series of samples. In order to apply this examination for routine purposes we describe in this paper acceleration and full automatization of the original chromatographic method allowing quantitation of hemoglobin A1c in 45 min.

Cerebrospinal fluid enzymology: creatine kinase, lactate dehydrogenase activity and isozyme pattern as a brain damage index

Blood serum and cerebrospinal fluid from a 4.5-year-old girl suffering from convulsive episodes of toxic origin were investigated for lactate dehydrogenase (LDH) and creatine kinase (CK) activities. Elevated levels of both enzymes were found. Furthermore CK was higher in the CSF (680 I.U./1) than in blood serum (160 I.U./1). The CSF activity was demonstrated mainly as the BB form (96%) for CK and H4 (63%) was the predominant form for LDH. Identical investigations were performed 45 h later and results compared with the first set. These data provide an additional example of interest in CSF enzymatic studies as a brain damage index.

Mitochondrial DNA polymerase, deoxyribonuclease and ribonuclease H activities from brain of chick embryo

R-DNA polymerase, D-DNA polymerase, DNase and RNase H activities in mitochondria from chick embryonic brain were studied by ion-exchange chromatography. Two main fractions were separated according to their chromatographic behaviour: a fraction M Ib which is eluted with the washing buffer from two successive DEAE-cellulose columns and a fraction M IV which is eluted at 400 mM KC1 from a phosphocellulose column. Although the two fractions contain both the DNA polymerase and the degrading activities, all the specific activities are higher in fraction M IV than in fraction M Ib. Heat inactivation experiments have shown that R-DNA polymerase is inactivated in both fractions, whereas RNase H and DNase are not affected. Thus, degrading activities and R-DNA polymerase activity seem to be catalyzed by different molecular entities. However the fact that in most cases these activities co-chromatograph suggests that the corresponding molecules form rather stable complexes.

Liaison entre histones et RNA. Action des proteines acides de la chromatine sur cette liaison

Histone is able to associate with radioactive RNA to form a complex which is retained on a millipore filter; 500 &mgr;g of histone F(1) from bone marrow is able to combine with 100 &mgr;g of RNA. Chromatin acidic proteins reduce this association up to 50%. The binding between RNA and histone does not occur in the presence of urea and NaCl.