Neonatal alloimmune thrombocytopenia due to anti-P1A1 (anti-hpa-1a): Importance of paternal and fetal platelet typing for assessment of fetal risk

Neonatal alloimmune thrombocytopenia (NAIT), which usually involves sensitization to P1^A1 (HPA-1a), may have devastating complications for the fetus. These may be prevented by antenatal treatment of severe cases with either maternally administered high-dose gamma-globulin and/or repeated intrauterine platelet transfusions. Determination of the paternal platelet phenotype is useful for counselling parents who have had one or more affected pregnancies. This report of an unaffected pregnancy in a woman with a history of previous pregnancies complicated by NAIT illustrates the role of paternal and fetal platelet phenotyping in managing existing pregnancies at risk of NAIT.     

Techniques and Guidelines for Monitoring Neotropical Butterflies

Long-term monitoring of selected species can identify changes in biological diversity, permitting the timely adjustment of management activities to reverse or avoid undesired trends. This paper addresses several related issues bearing on the development of inexpensive and easily implemented monitoring programs for tropical butterflies. First, we discuss the use of butterflies as ecological indicators. Next, we present field evaluations of butterfly sampling techniques, indicating that: (1) light-gap size greatly affects sampling results in forests and should be of critical concern in site selection and sampling design; (2) baited traps and visual censuses provide complementary data on butterfly abundances; (3) monitoring a subset of locally common butterfly species can provide data for comparing community composition and relative abundance of species in areas where species inventories are incomplete. Drawing on these results, we develop guidelines for designing monitoring programs. These address the formulation of explicit questions to be addressed through monitoring and the selection of appropriate study sites, study species, sampling techniques, and sampling frequency. A protocol for the ongoing butterfly monitoring program that emerged from these studies is appended. The techniques and guidelines presented here are intended to serve as an adaptable model for biologists designing monitoring projects to help guide applied conservation efforts in the tropics.     

Employee behaviors before and after stress management

A quasi-experiment was used to compare employee behaviors before and after stress management training. Organizational records on employee absenteeism, performance ratings, equipment accidents, and work injuries were obtained for highway maintenance workers who received biofeedback (BIO=21) or muscle relaxation (MR=16) training. Similar data were gathered for a comparison group of employees who did not volunteer for training (n = 80). The pre-training period (time 1) consisted of 2 1/2 years. The post-training period was divided into the year immediately after training (time 2) and the following 1/2 year (time 3). Multiple regression analyses indicated that the MR (but not BIO) group variable explained unique variance in time 2 absenteeism (p < 0.05) but not in performance ratings, equipment accidents, nor work injuries (p > 0.05). Neither group entered predictive models for any measure at time 3 (p > 0.05). The results provide limited support for relaxation training offered as a prevention activity in work settings.     

The OECD Validation Program of the H295R Steroidogenesis Assay for the Identification of In Vitro Inhibitors and Inducers of Testosterone and Estradiol Production. Phase 2: Inter-Laboratory Pre-Validation Studies (8 pp)

Background, Goals and Scope In response to concerns that have been raised about chemical substances that may alter the function of endocrine systems and result in adverse effects on human health, an OECD initiative was undertaken to develop and validate in vitro and in vivo assays to identify chemicals that may interfere with endocrine systems of vertebrates. Here we report on studies that were conducted to develop and standardize a cell-based screening assay using the H295R cell line to prioritize chemicals that may act on steroidogenic processes in humans and wildlife. These studies are currently ongoing as part of the ‘Special Activity on the Testing and Assessment of Endocrine Disruptors’ within the OECD Test Guidelines Program to review, develop, standardize, and validate a number of in vitro and in vivo toxicological assays for testing and assessment of chemicals concerning their potential to interact with the endocrine system of vertebrates. Study Design Six laboratories from five countries participated in the pre-validation studies. Each laboratory tested the effects of three model chemicals on the production of testosterone (T) and estradiol (E2) using the H295R Steroidogenesis Assay. Chemicals tested were well described inducers or inhibitors of steroidogenic pathways (forskolin, prochloraz and fadrozole). All experiments were conducted in 24 well plates following standard protocols. Six different doses per compound were analyzed in triplicate per plate. A quality control (QC) plate was run in conjunction with the chemical exposure plate to account for inter-assay variation. Each chemical exposure was conducted two or three times. Results All laboratories successfully detected increases and/or decreases in hormone production by H295R cells after exposure to the different model compounds and there was good agreement in the pattern of response for all groups. Forskolin increased both T and E2 while fadrozole and prochloraz decreased production of both hormones. All chemicals affected hormone production in a dose-dependent manner with the exception of fadrozole which caused maximum inhibition of E2 at the two least concentrations tested. Some inter-laboratory differences were noted in the alteration of hormone production measured in chemically exposed cells. However, with the exception of the production of T measured at one laboratory in cells exposed to forskolin, the EC₅₀s calculated were comparable (coefficients of variation 34–49%) for all hormones. Discussion and Perspectives The results indicated that the H295R Steroidogenesis Assay protocol was robust, transferable and reproducible among all laboratories. However, in several instances that were primarily related to one laboratory there were unexplained minor uncertainties related to the inter-laboratory hormone production variation. Based on the findings from this Phase 2 prevalidation study, the H295R Steroidogenesis Assay protocol is currently being refined. The next phase of the OECD validation program will test the refined protocol among the same group of laboratories using an extended set of chemicals (∼30) that will include positive and negative chemical controls as well as a broad spectrum of different potential inducers and inhibitors of steroidogenic pathways. Submission Editor: Dr. Carsten Brühl (bruehl@uni-landau.de)     

Fluorinated natural products: the biosynthesis of fluoroacetate and 4-fluorothreonine in Streptomyces cattleya

Organofluorine compounds are rare in Nature, with only a handful known to be produced by some species of plant and two microorganisms. Consequently, the mechanism of enzymatic carbon-fluorine bond formation is poorly understood. The bacterium Streptomyces cattleya biosynthesises fluoroacetate and 4-fluorothreonine as secondary metabolites and is a convenient system to study the biosynthesis and enzymology of fluorometabolite production. Using stable-isotope labelled precursors it has been shown that there is a common intermediate in the biosynthesis of the fluorometabolites, which has recently been identified as fluoroacetaldehyde. Studies with cell-free extracts of S. cattleya have identified two enzymes, an aldehyde dehydrogenase and a threonine transaldolase, that are involved in the biotransformation of fluoroacetaldehyde to fluoroacetate and 4-fluorothreonine.     

Stochastic-convective transport with nonlinear reaction and mixing: application to intermediate-scale experiments in aerobic biodegradation in saturated porous media

Aerobic biodegradation of benzoate by Pseudomonas cepacia sp. in a saturated heterogeneous porous medium was simulated using the stochastic-convective reaction (SCR) approach. A laboratory flow cell was randomly packed with low permeability silt-size inclusions in a high permeability sand matrix. In the SCR upscaling approach, the characteristics of the flow field are determined by the breakthrough of a conservative tracer. Spatial information on the actual location of the heterogeneities is not used. The mass balance equations governing the nonlinear and multicomponent reactive transport are recast in terms of reactive transports in each of a finite number of discrete streamtubes. The streamtube ensemble members represent transport via a steady constant average velocity per streamtube and a conventional Fickian dispersion term, and their contributions to the observed breakthroughs are determined by flux-averaging the streamtube solute concentrations. The resulting simulations were compared to those from a high-resolution deterministic simulation of the reactive transport, and to alternative ensemble representations involving (i) effective Fickian travel time distribution function, (ii) purely convective streamtube transport, and (iii) streamtube ensemble subset simulations. The results of the SCR simulation compare favorably to that of a sophisticated high-resolution deterministic approach.     

Predicting the occurrence of radon-222 in groundwater supplies

The intent of this study was to develop an understanding of some of the factors that affect the concentration ol radon-222 (²²²Rn) in drinking water supplies derived from groundwater, with specific application to North Carolina. Data for this investigation were collected on a sample of 96 North Carolina public water supply wells. Water samples were collected and analyzed for²²²Rn content. Data on site geology and well characteristics (discharge, specific capacity, depth, and casing length) were obtained from existing sources. From a statistical examination of the data collected in this study, we conclude that there is a distinct and statistically significant difference in the mean²²²Rn concentrations of groundwater associated with different types of rocks. The data, however, also indicate that there is a great degree of variability in the²²²Rn concentrations of samples drawn from any giver rock type. The situation is made slightly better by introducing a second variable given as the geologic region of a water supply. A fairly surprising finding of this study is the relative insignificance of discharge, specific capacity, depth, and casing length of wells as predictors of²²²Rn concentration. The present study indicates that use of these variables as predictors does not significantly improve the likelihood of locating water supplies with elevatec²²²Rn concentrations.     

The response of female Mountain White-crowned Sparrows to songs from their natal dialect and an alien dialect

Summary Female Mountain White-crowned Sparrows from Colorado were tested in a laboratory playback experiment to determine their response to male songs from their own natal dialect and to those from an alien dialect of the same subspecies, Zonotrichia leucophrys oriantha (Fig. 1). Observations were made on locomotor activity and copulation postures produced during each experimental test session.The subjects gave copulation displays almost exclusively when hearing their natal dialect and new or no displays when hearing the alien dialect (Fig. 2). The birds also exhibited significantly greater locomotor activity when hearing the natal dialect than they did when hearing the alien dialect (Fig. 3).We conclude that females are sensitized by their early song learning experience to be responsive to songs from their natal dialect and virtually sexually unresponsive to songs from an alien dialect. We speculate that the copulation posture given in the experiment implies that females in natural populations would preferably only mate assortatively with males from their natal dialect region.