Analysis of hemoglobin and globin chain variants by a commonly used capillary isoelectric focusing method

To analyze both hemoglobin (Hb) and globin chain variants, we modified a commonly used method, capillary isoelectric focusing (CIEF), with detection at 280 nm. The samples were hemolysates prepared from red blood cells, and globin chains obtained from the hemolysates by treatment with cold acidified acetone. When the migration time for the internal reference, carbonic anhydrase I (isoelectric point, pI 6.60), was taken as 1.0, the migration ratio for Hb A0 in normal human blood was 0.877 +/- 0.004 (mean +/- SD, n = 9), and those of the alpha- and beta-globin chains were 0.673 +/- 0.004 and 0.847 +/- 0.005 (mean +/- SD, n = 4), respectively. The ratio of peak heights between the beta- and alpha-globin chains (beta/alpha) in the normal Hbs obtained from four subjects was almost constant at 2.5 +/- 0.1 (mean +/- SD). This ratio indicates which of the globin chains includes a mutation (if one exists). When an Hb variant, Hb Hoshida (in which Gln is substituted for Glu at residue 43 in the beta-globin chain), was analyzed by this method, two main peaks were observed (migration ratios 0.836 and 0.877, corresponding to an abnormal and the normal Hb, respectively). An additional peak with an abnormal migration ratio of 0.788 was also detected in the globin chain profiles. The ratio of peak heights between normal beta- and alpha-globin chains was 1.57, indicating that a mutation exists in the beta-globin chain. We thus established a convenient system using CIEF that provides a rapid and reproducible method for the random analysis of both Hb and globin chain variants.

[Appearance of ovomucoid in coagulated egg yolk passing through from soluble fraction of coagulated egg white in boiled egg]

Ovomucoid is a egg white protein which has a strong allergenicity with a unique characteristic in heat-noncoagulable one contrast to heat-coagulable other major egg white proteins. By ELISA and immunoblots analysis, ovomucoid was detected in heat-coagulated egg yolk after immediate boiling of hen's egg for 15 min (boiled egg) at the concentration of 4.8 +/- 0.8 micrograms/g egg yolk, but not detected in raw egg yolk collected by insertion of a needle into the egg yolk cavity. Ovomucoid in heat-coagulated egg yolk was increased by standing the boiled eggs at room temperature for 10, 30, 60 and 120 min at the concentration of 7.5 +/- 3.4, 17.2 +/- 15.1, 28.1 +/- 5.9 and 78.8 +/- 31.3 micrograms/g egg yolk, respectively. The soluble fraction prepared from heat-coagulated egg white of boiled egg contained 37.7 +/- 3.2 mg/ml of proteins including 14.2 +/- 11.9 mg/ml of ovomucoid as a major and miners of detectable ovalbumin and ovotransfferin. These results suggested that the appearance of ovomucoid in coagulated egg yolk of boiled egg was due to passing the soluble fraction rich in ovomucoid in heat-coagulated egg white through into the coagulated egg yolk, which may have notable consequences for the present of ovomucoid as a major egg white allergen in yolk egg of boiled egg.

Characterization of single chain urokinase-type plasminogen activator with a novel amino-acid substitution in the kringle structure

ECV304 is a cell line established by a spontaneous transformation of endothelial cells of a human umbilical vein. It was shown that ECV304 secretes single chain urokinase-type plasminogen activator (scu-PA). A subclone, ECV304 clone 15, was obtained by acclimatization of parental clone to serum-free medium followed by limiting dilution. The clone was found to produce approximately five times as much scu-PA (approximately 20 IU/10(6) cells per day) as the parental clone after a 40 days' culture. Though the biochemical characteristics of the purified scu-PA were indistinguishable from those of the native scu-PA, it had a lower affinity for fibrin clots under the employed conditions. Molecular cloning of a cDNA encoding the scu-PA has identified a novel substitution from C to T in the nucleotide sequence encoding the kringle structure. The substitution resulted in an alteration from Pro (CCG) to Leu (CTG) at amino-acid position 121, which may be directly or indirectly involved in the decrease in the apparent affinity.

Noninvasive recording of His bundle activity with an analog delay device in normal subjects and patients with atrioventricular block

A simplified and clinically applicable method has been developed for real-time noninvasive recording of the electrical activity of the His bundle in the human heart. A surface electrocardiogram (ECG) was obtained from bipolar precordial leads. The electrical signal within the P-QRS segment of the ECG was amplified with a high gain amplifier and delayed with an analog delay device for QRS-triggered signal averaging. The analog delay device consisted of a bucket brigade device (BBD) with an electrical integrated circuit (IC). After filtering with a band width of 50-300 Hz, the delayed signal was processed by a microcomputer system and the signal-to-noise ratio of the signal was improved by the signal averaging technique. Surface His bundle electrocardiograms (SHE) were measured in normal subjects without conduction disorders and in patients with atrio-ventricular (A-V) block. In the same patients, each SHE was nonsimultaneously compared with an invasive His bundle electrogram (HBE) obtained by the intracardiac catheter technique. The results of this comparison confirmed that the noninvasive method of SHE recording has broad clinical applicability and high utility for the screening of patients with latent A-V block before intracardiac catheterization is performed.

Purification and partial characterization of K+ channel blockers from the venom of Dendroaspis angusticeps

Two polypeptides (designated DTX-A and DTX-B) were purified from crude snake venom of Dendroaspis angusticeps using gel filtration, cation exchange column chromatography and cation exchange high performance liquid chromatography, and their blocking actions of K+ channels were investigated in rat brain synaptosomes. Both DTX-A and DTX-B inhibited the voltage-dependent 42K efflux from the synaptosomes. DTX-A blocked 42K efflux of both the rapidly inactivating phase (component T) and the slowly inactivating phase (component S). The inhibitory effect of DTX-A on component T was pronounced compared with that on component S. However, DTX-B selectively blocked 42K efflux of component S. The molecular weights of DTX-A and DTX-B were estimated to be ca 10,000 by SDS-polyacrylamide gel electrophoresis. The amino acid composition of these toxins is different from that of polypeptide purified from the venom of D. angusticeps (alpha-, beta-, gamma- and delta-DTX). These results suggest that DTX-A and DTX-B are new polypeptides which block voltage-dependent K+ channels selectively, and that they are useful tools for investigating the K+ channel.