Ejection fraction by combined inverse Fourier analysis and second-derivative technique: Correlation with isocontour method

Summary In order to measure ejection fractions (EFs) from nuclear ventriculograms, we devised a semi-automated edge-detection technique based on a combination of inverse Fourier analysis and second-derivative techniques. Initial clinical studies showed that, for the left ventricle, our method gives EF values statistically identical with those obtained using a conventional isocontour technique. For the right ventricle, however, the values obtained using the two methods were somewhat more at variance. Despite requiring a longer processing time, the results obtained with our method are reproducible because less operator intervention is necessary.     

Inhibition of intercellular adhesion molecule 1-dependent biological activities by a synthetic peptide analog.

We have used a combination of hydropathy analysis of the intercellular adhesion molecule 1 (ICAM-1) sequence and dot-matrix comparison of the sequence with the homologous, but functionally distinct, protein myelin-associated glycoprotein to identify a putative functional binding region. One polar, and presumably surface-exposed, region of ICAM-1 showed no significant identity with myelin-associated glycoprotein. A synthetic peptide analog based on the sequence of this region (JF9) mimicked the inhibitory effects of the anti-ICAM-1 monoclonal antibody WEHI-CAM-1. These included inhibition of ICAM-1-dependent homotypic aggregation of Raji Burkitt lymphoma and phorbol-ester treated U937 cells at concentrations as low as 80 micrograms/ml (24 microM). In addition, at a concentration of 100 micrograms/ml, the peptide analog effectively inhibited cytotoxic cell activity, an ICAM-1-dependent effector function of the immune response. This simple method of sequence analysis may have general applicability to the identification of functional domains in homologous, but functionally distinct, proteins such as the translated products of gene families.     

Reproducibility of lateral spine scans using dual energy X-ray absorptiometry

Summary Reproducibility of lateral spine dual energy X-ray absorptiometry (LAT DEXA) scans using a Lunar DPX-L scanner was assessed in a cadaveric phantom and in patients. One hundred phantom measurements over 7 months demonstrated a longitudinal stability of 1.7% (coefficient of variation, CV). Additional scans were performed with the phantom rotated by up to 20° in each of the three orthogonal planes to assess the effects of variable patient positioning. Horizontal and vertical rotation of the spine had little effect on the estimated bone mineral density (BMD), however, axial rotation of greater than 8° led to errors in the BMD measurement. One hundred consecutive patients had two lateral scans performed within 1 month. BMD (range 0.10–1.6 g/cm²) was determined for each scan by one operator. Significant overlap from ribs and pelvis was often seen with L2 and L4 vertebrae but one vertebra (L3) could be measured in every case. Intraoperator and interoperator variability was assessed by three experienced operators, each analyzing 10 patients' scans on five separate occasions, and was found to be less than 1.1% for a single vertebra. BMD estimation of vertebral bodies and midslices by lateral DEXA scans (CV% of 3.8% and 4.6%) have a 95% confidence interval of 0.074 g/cm² and 0.096 g/cm², respectively for two vertebrae. This variability is due mainly to axial rotation, with operator variability, horizontal rotation, and vertical rotation having little effect on BMD estimation.     

Effect of cigarette smoking on the specific antibody response in pigeon fanciers.

Titres of circulating IgG antibodies to pigeon gammaglobulin and end expired carbon monoxide concentrations were measured in 86 pigeon fanciers attending the "Show of the Year." Antibody levels were significantly higher in non-smokers and in those with end expired carbon monoxide concentrations below 10 parts per million.     

Determination of the levels of urokinase and its receptor in human colon carcinoma cell lines

At present, there is a lack of availability of differentiation markers for colon carcinoma. This may, in part, be a consequence of the diversified function of the normal human colon. This study addresses the possibility that the expression of urokinase and its receptor is inversely related to differentiation in colon carcinoma. Six colon carcinoma cell lines including three well-differentiated (CBS, GEO, FET) and three poorly differentiated ones (HCT116, HCT116b, RKO) were screened for urokinase receptor display and secretion of the plasminogen activator. A radioreceptor assay was used to determine receptor levels. Binding of radioactive urokinase to colon cells was saturable, specific, and time dependent. Cell-bound 125I-labeled protease was unaffected by the presence of epidermal growth factor, low-molecular-weight urokinase, plasminogen, or transferrin. Time course studies revealed that maximum amounts of radioactive tracer were bound in a 30-min period with no change occurring over the course of a 90-min incubation. Scatchard analysis of ligand binding indicated that the well-and poorly differentiated cells could be separated on the basis of receptor display; the aggressive RKO, HCT116, and HCT116b expressed in excess of 10(5) sites per cell, while the more indolent CBS, GEO, and FET possessed less than 1.5 X 10(4) receptors per cell. The colon carcinoma cells were also analyzed for urokinase in the conditioned medium. Low levels of the plasminogen activator (0.8 to 1.3 ng/ml/10(6) cells/72 h) were associated with the more "mature" cells. This was in contrast to the elevated levels of the protease (3.9 to 11.4 ng/ml/10(6) cells/72 h) present in the medium derived from the more aggressive cells (HCT 116, HCT116b, RKO). Thus, secreted urokinase and/or the expression of cellular receptor for the plasminogen activator may provide useful measurements of the degree of undifferentiation of in vitro colon carcinoma.     

An explanation for the decrease in cell lysis in a rotating tube with increasing ultrasound intensity

Previous observations indicate that for in vitro mammalian cells insonated in rotating test tube the amount of cell lysis initially increases to some maximum and then decreases with further increase in ultrasound exposure. The results of the present investigation support the postulate that the reduction in cell lysis with increase in ultrasound intensity is related to the development of an ultrasonically induced "cloud" of bubbles in the fluid between the transducer and test tube; these bubbles mitigate against acoustic transmission thus reducing cell lysis in the insonated test tube.     

Evolutionary genetic analysis of the emergence of epidemic Vibrio cholerae isolates on the basis of comparative nucleotide sequence analysis and multilocus virulence gene profiles

Vibrio cholerae, the causative agent of cholera, is a natural inhabitant of the aquatic ecosystem. We examined a unique collection of V. cholerae clinical and environmental isolates of widespread geographic distribution recovered over a 60-year period to determine their evolutionary genetic relationships based on analysis of two housekeeping genes, malate dehydrogenase (mdh) and a chaperonin (groEL). In addition, the phylogenetic distribution of 12 regions associated with virulence was determined. Comparative sequence analysis of mdh revealed that all V. cholerae O1 and O139 serogroup isolates belonged to the same clonal lineage. Single-strand conformational polymorphism (SSCP) analysis of these O1 and O139 strains at groEL confirmed the presence of an epidemic clonal complex. Of the 12 virulence regions examined, only three regions, Vibrio seventh pandemic island 1 (VSP-I), VSP-II, and RS1, were absent from all classical V. cholerae isolates. Most V. cholerae El Tor biotype and O139 serogroup isolates examined encoded all 12 virulence regions assayed. Outside of V. cholerae O1/O139 serogroup isolates, only one strain, VO7, contained VSP-I. Two V. cholerae El Tor isolates, GP155 and 2164-78, lacked both VSP-I and VSP-II, and one El Tor isolate, GP43, lacked VSP-II. Five non-O1/non-O139 serogroup isolates had an mdh sequence identical to that of the epidemic O1 and O139 strains. These isolates, similar to classical strains, lack both VSP-I and VSP-II. Four of the 12 virulence regions examined were found to be present in all isolates: hlyA, pilE, MSHA and RTX. Among non-O1/non-O139 isolates, however, the occurrence of the additional eight regions was considerably lower. The evolutionary relationships and multilocus virulence gene profiles of V. cholerae natural isolates indicate that consecutive pandemic strains arose from a common O1 serogroup progenitor through the successive acquisition of new virulence regions.     

Preparation of primary monolayer cultures of mouse pancreatic epithelial cells

Summary We describe a technique using normal and diabetic (dbdb) mice to establish primary pancreatic cultures that spread and assume a characteristic epithelial morphology. These cultures contain 4 to 7% beta cells, secrete insulin in response to stimuli for 10 to 14 d, contain few fibroblasts, and have a cell viability that is greater than 95%. The cells attach firmly to glass cover slips and are ideal for the study of insulin secretory granules or contractile proteins using indirect immunofluorescence.