Fast atom bombardment and collisional activation mass spectrometry in the structural analysis of steroidal oligoglycosides

Fast atom bombardment (FAB) followed by collisional activation (CA) mass spectrometry was used for structural analysis of steroidal oligoglycosides, containing two to four sugar units. In the molecular ion region of the FAB mass spectra of these underivatized natural products, intense protonated molecular ions were observed. The collisional activation spectra of these mass selected ions yield more sequence information than FAB mass spectra and are not contaminated with interfering peaks originating from impurities or matrix.

Value of two-dimensional echocardiography in evaluating coronary artery disease: a randomized blinded analysis

Two-dimensional echocardiography at rest was used to analyze segmental wall motion abnormalities for detecting coronary artery disease in patients with and without a history of myocardial infarction. One hundred twenty-five echocardiograms were analyzed in a randomized, blinded fashion. They were obtained from 55 consecutive patients found to have significant coronary artery disease at angiography, 59 consecutive normal subjects and 11 patients with dilated cardiomyopathy. The overall sensitivity of two-dimensional echocardiography was relatively low at 67%. However, specificity was 99%. The sensitivity was higher in patients with past myocardial infarction than in those without myocardial infarction (81 versus 42%), as expected. Echocardiography can detect segmental wall motion abnormalities in some patients with coronary artery disease and no overt prior myocardial infarction. This was highlighted by nine such patients with coronary artery disease and no prior myocardial infarction or electrocardiographic Q waves who were found to have segmental wall motion abnormalities. A semiquantitative, two-dimensional echocardiographic segmental wall motion score was derived for 47 patients and was correlated with angiographic left ventricular ejection fraction (r = 0.71). This score differentiated patients with a normal ejection fraction (greater than 50%) from those with a depressed ejection fraction (less than 50%): 1.1 +/- 1.6 versus 6.9 +/- 3.1 (p less than 0.001). Almost all patients (92%) with an echocardiographic score of five or more had an abnormal ejection fraction of less than 50%. In patients with chronic congestive heart failure, the echocardiogram separated those with dilated cardiomyopathy from those with coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

An inhibitor of catalase induced by cold in chilling-sensitive plants

An inhibitor of catalase accumulated when leaves of chilling-sensitive species were stored in the dark at 0 degrees C. The inhibitor could be removed from crude extracts by passing them through a column of Sephadex G-25. After this treatment, the catalase activity of extracts of chilled tissues was found to be equal to that of extracts from unchilled leaves. When chilled tissues were incubated at 20 degrees C, the inhibitor of catalase was lost, unless the tissues had been irreversibly damaged. It specifically inhibited plant catalase, and had no effect on mammalian catalase, plant malic dehydrogenase, or plant superoxide dismutase.Despite the presence of catalase inhibitor in extracts of chilled plants, no increase in the level of H(2)O(2) in chilled tissues was found, suggesting either that the inhibitor is compartmentalized and not in contact with catalase in vivo, or that the level of H(2)O(2) is controlled by means other than through catalase activity. Plant tissues normally contain H(2)O(2) which is destroyed by catalase when they are damaged. After chilling, H(2)O(2) leaking from already injured cells would not be so readily removed by the inhibited catalase, and could contribute to further injury by acting as a source of free radical oxidants.

Identification and characterization of luteinizing hormone-releasing hormone (LH-RH) receptors in the endometrial tissue of pregnant rats

The mechanisms by which LH-RH or its agonists inhibit decidua formation and terminate pregnancy in rats are not clear. Evidence so far accumulated indicates that the gonadotropic releasing hormone or its analogues may act directly on the uterus. If this is the case, then we would be able to identify LH-RH receptors in the endometrial tissue. The results presented here demonstrate that the homogenate preparation of rat endometrial tissue bound 125I-LH-RH with an affinity constant of Ka = 1.3 X 10(8) M-1. The binding capacity was measured as 236 fmole/mg protein. It was found that the binding is highly specific, because no binding was observed in a variety of non-target tissues, such as liver, kidney and muscle. Competitive binding with TRH, P substance and bradykinin did not occur under our experimental condition. It was of particular interest to note that Day 3 of pregnancy is a critical time showing a higher binding activity. The significance of work is discussed.

Prostaglandin E and F2 alpha levels in plasma and amniotic fluid during mid-trimester abortion induced by trichosanthin

This paper gives a brief account concerning the estimation of PGE and PGF2 alpha concentrations in both plasma and amniotic fluid by radioimmunoassay in mid-trimester abortion induced by Trichosanthin. The significant change in amniotic fluids as compared with that in plasma is brought out for discussion as an aid to the study of mechanism of abortion by Trichosanthin.