Identification of a heroin esterase in Rhodococcus sp. strain H1

A strain of a Rhodococcus sp. (termed H1) capable of utilizing heroin as its sole carbon and energy source was isolated by selective enrichment. An inducible heroin esterase was partially purified and shown to catalyze the hydrolysis of both of the acetylester groups of heroin. The enzyme displays optimum activity at pH 8.5 and appears to be a trimer of identical subunits with an M(r) or 39,000 and a native M(r) of 120,000.     

Rapid thin layer chromatographic method for the detection of histamine in fish products

A rapid, convenient thin layer chromatographic (TLC) method for detecting histamine in fish samples is described. Samples of press juice or fish flesh are applied directly to TLC plates. The plates are developed with acetoneammonium hydroxide (95+5) and the spots are visualized with ninhydrin or Pauly's reagent. Chromatographic separation of histamine from other fish components is readily achieved by this method.     

Metabolism of catechol estrogen by human erythrocytes

In a study designed to evaluate the kinetics of catechol estrogen formation from plasma estrone in vivo, we obtained evidence that the red blood cell (RBC) enzyme, catechol-O-methyl transferase, catalyzes the transformation of 2-hydroxyestrone to 2-methoxyestrone. Under in vitro conditions, the rate of conversion of 2-hydroxyestrone to 2-methoxyestrone by human RBC's was such that 7 nmol of 2-methoxyestrone were formed per h per ml of RBC.     

Longitudinal ureteral split for retroperitoneal fibrosis with ureteral involvement

Idiopathic retroperitoneal fibrosis may rarely invade the ureteral wall, thereby rendering the attempt to perform classical ureterolysis futile. Possibilities for surgical correction include resection with end-to-end anastomosis, utilization of a spiral strip of ureter, small bowel substitution, iatrogenic nephroptosis or longitudinal incision of the involved ureter down to the mucosa. Two patients treated using the latter technique have been followed for 7 months and 132 months without recurrence of the obstructive process. The surgeon, when treating idiopathic retroperitoneal fibrosis, must be prepared to treat intrinsic ureteral involvement using the most appropriate surgical technique.     

Interactive effects of maternal and dietary mercury exposure have latent and lethal consequences for amphibian larvae

Organisms born into the same contaminated environment as their parents can be exposed both maternally and environmentally to contaminants, potentially placing them at greater risk of adverse effects than when exposed via either of the two pathways independently. We examined whether embryonic exposure to maternally derived mercury (Hg) interacts with dietary exposure to negatively influence larval development in American toads ( Bufo americanus ). We collected eggs from breeding pairs at reference and Hg-contaminated sites and monitored performance, development, and survival of larvae fed three experimental Hg diets (total Hg, 0.01, 2.5, and 10 μg/g). The negative sublethal effects of maternal and/or dietary Hg manifested differently, but maternal Hg exposure had a greater overall influence on offspring health than dietary exposure. However, the combination of sublethal effects of the two exposure routes interacted with lethal consequences; larvae exposed to maternal Hg and high dietary Hg experienced 50% greater mortality compared to larvae from reference mothers fed the control diet. This study is the first to demonstrate that the latent effects of maternally transferred contaminants may be exacerbated by further exposure later in ontogeny, findings that may have important implications for both wildlife and human health.     

Some statistical implications of rounding in the College of American Pathologists Survey

Quantitative measurements of constituent concentrations of Survey specimens are generally recorded to the nearest integer or to the nearest tenth. Questions have arisen as to whether this degree of rounding of measurements is appropriate when available laboratory equipment can determine results more precisely. Statisticians have studied the effects of rounding off on an variety of standard statistical procedures. In this report biases that may result for estimates of the mean and variance from several typical data sets obtained in the 1975 College of American Pathologists (CAP) Survey are examined. The study indicates that the amount of bias in the sample mean and variance is generally minimal.