Nuclear protein 780BP from cauliflower binds an element in the 780 gene promoter of T-DNA.

A 16 bp site of protein binding has been identified in the promoter of the 780 gene of T-DNA. Specific DNA-protein interactions were demonstrated between a double-stranded oligonucleotide containing this element (5'-TTGAAAAATCAACGCT-3') and a protein isolated from nuclear extracts of cauliflower inflorescences. Specific bases required for this binding activity (780 binding protein; 780BP) were defined by kinetic competition studies with mutated oligonucleotides, methylation interference assays and DNAse I footprinting. 780BP binding was not competed with up to 1000-fold excess of previously characterized plant regulatory elements such as as-1, the LRE, and the ocs, G-box, and AT-rich elements. In addition, 780BP was shown to bind sequences overlapping a mammalian hormone receptor element with greater affinity than the 780 element.

Differentiation of myoglobin and hemoglobin in biological fluids.

The use of several methods to differentiate myoglobin from hemoglobin has been investigated. The immunochemical methods, particularly those of hemagglutination inhibition and radioimmunoassay, are the most useful. This report summarizes work in the Ames Research Laboratory over the past 17 years with the several methods.

Radioimmunoassay for serum myoglobin.

A column flow-through radioimmune assay for serum myoglobin has been developed. The assay uses antibodies to human or rhesus monkey myoglobin coupled to Sepharose by cyanogen bromide activation and myoglobin labeled by the Chloramine-T method. The labeled myoglobin is stable over two to three half-lives. Serum myoglobin levels were elevated when serum was taken up to 12 hours after myocardial infarction and generally elevated up to 24 hours. A continued or repeated elevation of serum myoglobin probably indicates continued myocardial damage or new attacks. In the cases of myocardial infarction, levels up to 1340 ng per ml were found.

A rapid, flow-through column radioimmunoassay for human chorionic somatomammotropin.

A rapid, flow-through, column, nonequilibrium radioimmunoassay for human chorionic somatomammotropin (HCS) is described. The total incubation time is about 1 hour, and no centrifugation is needed. Reproducibility, sensitivity, specificity, recovery, and parallelism are adequate for clinical utility. Hormone levels in a variety of pregnancy sera assayed by this column method are closely related to results from another more conventional radioimmunoassay method.

Acute myocardial infarction diagnosed by myoglobinuria.

Myoglobin can be found in excess in the urines of some patients with acute myocardial infarction. To test the specificity of this finding, urine specimens were analyzed from 39 patients with provisional diagnosis of myocardial infarction by means of a hemagglutination-inhibition technique with prepared antisera to monkey myoglobin. Of 24 patients with subsequently documented myocardial infarction, 15 had at least one positive determination. None of the 15 patients without infarction had positive tests. Ten of 13 patients with infarction studied within 24 hours of the initial event had positive reactions. The percentage of positive reactions in the infarct group decreased sharply after the first 24 hours. This technique may be of value in rapid screening of patients with possible acute myocardial infarction during early stage of symptoms.

Calorimetric studies of the haemoglobin-haptoglobin reaction.

Haptoglobin binds haemoglobin so firmly that there is practically no dissociation. It would be expected that the heat of the reaction would be relatively large. The development of the microcalorimeter by Benzinger offered the opportunity to measure the heat of reaction. The experiments were carried out in the Beckman 190B Microcalorimeter in two ways: (1) a constant amount of haptoglobin (Kabi; 65mg.) with different amounts of haemoglobin, and (2) a constant amount of haemoglobin (32.5mg.) with different amounts of haptoglobin. The proteins, each in 5ml. of 0.15m-phosphate buffer, pH7.4, were placed in equal-volume calorimeter cells. The heat produced/mg. of haemoglobin was calculated from the slope of the curve for a constant amount of haptoglobin and from the maximum heat for a constant amount of haemoglobin. This heat is about 70kcal./mole at 37 degrees . DeltaH varies with temperature, being -70.2 at 37 degrees , -29.7 at 20 degrees and 7.2 at 4 degrees . From the amount of haptoglobin required to attain maximum heat with 32.5mg. of haemoglobin and the amount of haemoglobin required to attain maximum heat with 65mg. of haptoglobin, it appears that at excess of haptoglobin there is competition between the reactions of 2moles of haptoglobin with 1mole of haemoglobin (or 2 alphabeta-chains) and 1mole of haptoglobin with 1mole of haemoglobin.

Studies on the human corpus luteum. II. Observations on the ultrastructure of luteal cells during pregnancy.

The ultrastructure of human corpora lutea obtained during the 6th, 10th, 16th, and 35th week of pregnancy is reported. Differences between the established luteal cell of pregnancy and the transitory luteal cell of the menstrual cycle are noted. In pregnancy the luteal cell is more compartmentalized into a peripheral mass of ER (endoplasmic reticulum) and a central area where mitochondria and Golgi complexes are concentrated. The latter area extends to a cell surface where microvilli face on a perivascular space. Long bundles of filaments are prominent within the luteal cell cytoplasm and, in contiguous cells, appear to arise from adjacent desmosomal regions. Bilateral subsurface cisternae of granular ER at lateral cell borders appear to be areas of specialized junctional surfaces. Certain luteal cells with irregular nuclear membranes are also characterized by vesicular aggregates enclosed within a single membrane. These aggregates are found within the peripheral nucleoplasm or the perinuclear cytoplasm. Their single limiting membrane often appears continuous with either the inner or outer leaflet of the nuclear membrane.