Two-dimensional echocardiography with a wide angle (60 degrees) sector scanner

A wide angle (60 degrees) sector scanner producing a real-time two-dimensional echocardiogram has been used to examine healthy infants, children, and adults. Its method of use is described and findings from longitudinal and transverse scans are presented. The points of difference between the various types of electronic and mechanical two-dimensional scanning systems are discussed. This equipment minimises problems of chest contact and rib and lung interference and, by providing echocardiograms of high line density from a wide angle, is a suitable real-time two-dimensional scanning system for examining patients of all ages.     

Conjugating plasmids are preferred targets for Tn7

Most transposons display target site selectivity, inserting preferentially into sites that contain particular features. The bacterial transposon Tn7 possesses the unusual ability to recognize two different classes of target sites. Tn7 inserts into these classes of target sites through two transposition pathways mediated by different combinations of the five Tn7-encoded transposition proteins. In one transposition pathway, Tn7 inserts into a unique site in the bacterial chromosome, attTn7, through specific recognition of sequences in attTn7; the other transposition pathway ignores the attTn7 target. Here we examine targets of the non-attTn7 pathway and find that Tn7 preferentially inserts into bacterial plasmids that can conjugate between cells. Furthermore, Tn7 appears to recognize preferred targets through the conjugation process, as we show that Tn7 inserts poorly into plasmids containing mutations that block plasmid transfer. We propose that Tn7 recognizes preferred targets through features of the conjugation process, a distinctive target specificity that offers Tn7 the ability to spread efficiently through bacterial populations.     

Late results of local transrectal hyperthermia in patients with benign prostatic hyperplasia and its complications

LTH on Yakhta-4M unit was used in benign prostatic hyperplasia (BPH). The prostate was heated transrectally by directional radiation. The course of treatment comprised 5 sessions for 60 min twice a week. The efficacy of the treatment was assessed 3 years later in 78 patients which were divided into 4 groups: 31 patients with BPH, 30 patients with BPH in combination with chronic prostatitis, 9 patients with acute urine retention and 8 patients with cystostomy fistula. 5 patients underwent surgery. LTH is safe in relation to side effects, may be used both at early stage of the disease and in risk of operative intervention.     

Protease inhibitors induce specific changes in protein tyrosine phosphorylation that correlate with inhibition of apoptosis in myeloid cells

To investigate early signaling events responsible for regulation of programmed cell death or apoptosis, we studied campothecin (a topoisomerase I inhibitor)-mediated apoptosis in the human promyelocytic leukemia cell line HL60. We demonstrate a tight correlation between protection of HL60 cells from apoptosis-associated internucleosomal DNA fragmentation by specific protease inhibitors or protein phosphatase inhibitors, with early tyrosine phosphorylation of a single protein substrate with a molecular weight of approximately 42,000. Exposure to protease inhibitors that did not protect HL60 cells from DNA fragmentation did not result in phosphorylation of this substrate. Likewise, a protein tyrosine kinase inhibitor that did not interfere with specific phosphorylation did not prevent DNA fragmentation. Taken together, these results suggest that phosphorylation of a Mr 42,000 substrate constitutes an important signaling event that may participate in regulation of the apoptotic response.     

Ocular chrysiasis correlated with gold concentrations in the crystalline lens during chrysotherapy

The eyes of 11 patients with rheumatoid arthritis (RA) who received extended chrysotherapy (mean cumulative dose greater than 7 grams during a mean 6-year period) were examined biomicroscopically. Minute reddish-purple particles were seen in the cornea (corneal chrysiasis) in 5 and in the lens (lens chrysiasis) in 4 patients. Particulate deposits were absent in 11 other RA patients who had not received gold treatment. Seven crystalline lenses from 5 gold-treated patients were removed surgically because of incidental cataract formation and analyzed for gold content using neutron activation analysis. Although the mean lens gold concentration was higher in these patients than in non-gold-treated controls without RA (0.0073 microgram/grams versus 0.001 microgram/grams), the absolute gold level was markedly lower than that found in 25 diverse tissue analyzed previously. This finding is compatible with the absence of clinical gold-related lens disease or visual impairment.     

Testosterone and the sex difference in blood pressure in mice

Blood pressure of adult male SWR/J mice is approximately 20 mm Hg higher than that of females. Castrating males at weaning eliminated this sex difference. Testosterone restored blood pressure of castrated mice to the level of the intact males within 10 days indicating a pressor effect of testosterone. Ovariectomy had no effect on blood pressure.     

Analytical techniques for cell fractions. XXIII. A stable thermal gradient device for heat denaturation studies on proteins

The ISO-DALT two-dimensional electrophoretic system (1,2), based on the method of O'Farrell (3), is capable of performing large numbers of analysis on complex mixtures of proteins. However, both separations employed are carried out under dissociating or denaturing conditions and no enzyme activities are readily observable in the analyzed proteins. In order to identify the spots corresponding to particular enzymes, it is therefore necessary to employ some nondestructive resolving technique first and as a second step to perform both enzyme and two-dimensional electrophoretic analyses on the fractions generated. By correlating enzyme activity with intensity of various spots on the two-dimensional gels throughout the series of initial fractions, identifications, can be made. This approach, unlike the more direct immunoprecipitation methods (4), requires the running of large numbers of enzyme analyses and two-dimensional gels and some convenient initial resolving procedure. Convenient and rapid techniques for the analyses (5,6) and gels (1,2) have been described previously in this series and elsewhere. This paper deals with the use of selective denaturation in a temperature gradient as an initial resolving procedure and describes a simple thermal gradient device for generating such a gradient.     

Measured change in protein solvation with substrate binding and turnover

Osmotic stress is used to measure solvation changes that accompany the conformational changes of an active enzyme. For hexokinase both the equilibrium dissociation constant and the kinetic Michaelis-Menten constant for glucose vary linearly, and to the same extent, with the activity of water in the protein medium, as adjusted with large molecular weight (> 2000) osmolytes. The variation over the whole osmotic pressure range studied indicates that glucose binding is accompanied by the release of at least 65 +/- 10 water molecules, and this is reversed on enzyme turnover. The results indicate that near the physiological range of pressures the number may be higher. Most of this water, which behaves like an inhibitor, likely comes from the cleft which is induced to close around the substrate. Such large dehydration/rehydration reactions during turnover imply a significant contribution of solvation to the energetics of the conformational changes. Osmotic stress is a method of general applicability to probe water's contribution to functioning molecules.