A protocol for determination of anticardiolipin antibodies by ELISA

The anticardiolipin (aCL) test has been widely used by physicians since the mid-1980s for diagnosing patients with antiphospholipid syndrome (APS). Establishment of this diagnosis has enabled effective management of patients with recurrent thrombosis or recurrent pregnancy losses. The test was first established in 1983 as a radioimmunoassay and soon thereafter converted into ELISA. There have been numerous efforts to standardize the aCL test, but precise reproducible measurement of aCL levels is difficult and the use of semiquantitative measurements (high, medium and low) is recommended as this is probably sufficient for clinical diagnosis. Using validated ELISAs for measuring aCL Abs offers greater reproducibility, would reduce interlaboratory variations and limit discrepancies in results between different laboratories. This article details a procedure that takes approximately 2 h and summarizes the information available on the aCL ELISA test.     

Prevalence of Escherichia coli in surface waters of Southeast Asian cities

Surface water samples were collected from rivers which fed into large urban areas within Vietnam, Indonesia, Cambodia, and Thailand and were processed to enumerate Escherichia coli. Selected isolates were further characterized using PCR to detect the presence of specific virulence genes. Analyzing the four countries together, the approximate mean cfu/100 ml for E. coli counts in the dry season were log 4.3, while counts in the wet season were log 2.8. Of the 564 E. coli isolates screened for the presence of pathogenic genes, 3.9 % possessed at least one virulence gene. The most common pathogenic types found were Shiga toxin-producing E. coli isolates. These results reinforce the importance of monitoring urban surface waters for fecal contamination, that E. coli in these water environments may serve as opportunistic pathogens, and may help in determining the impact water usage from these rivers have on the public health of urban populations in Southeast Asia.     

Solid cancer risk dependence on the Pasquill–Gifford atmospheric stability classes in a radiological event

In a radiological event, the lack of preliminary information about the site of explosion and the difficulty in predicting the accurate path and distribution of radioactive plumes makes it difficult to predict expected health effects of exposed individuals. So far, in such a health evaluation, radiation-induced stochastic health effects such as cancer are not included. The Pasquill–Gifford atmospheric classes generally allow connecting atmospheric stability with dispersion of radioactive contaminants to the environment. In this work, an environmental release of radioactive Cs-137 was simulated and the resulting relative risk for solid cancer incidence among the affected population calculated. The HotSpot health physics code was used to simulate the radioactive atmospheric dispersion and calculate the Total Effective Dose Equivalent (TEDE), which was then used to estimate the relative risk of cancer incidence. The main results from this work suggest that the relative cancer risk and atmospheric stability classes are linked by differences in the TEDE. Such a finding may support triage, because it adds additional information on the potentially affected population at the early stages of an emergency response.     

Hydrolysis of sucrose using sulfonated poly(vinyl alcohol) as catalyst

The hydrolysis of sucrose was carried out over poly(vinyl alcohol) (PVA) with sulfonic acid groups, at 80 °C. The products of sucrose hydrolysis were glucose and fructose. A series of PVA with different crosslinking degree were prepared. It was observed that the catalytic activity of PVA matrix increases with the crosslinking degree, due to the increases of the amount of sulfonic acid groups on PVA.     

Evaluating the Growth Potential of Pathogenic Bacteria in Water

The degree to which a water sample can potentially support the growth of human pathogens was evaluated. For this purpose, a pathogen growth potential (PGP) bioassay was developed based on the principles of conventional assimilable organic carbon (AOC) determination, but using pure cultures of selected pathogenic bacteria (Escherichia coli O157, Vibrio cholerae, or Pseudomonas aeruginosa) as the inoculum. We evaluated 19 water samples collected after different treatment steps from two drinking water production plants and a wastewater treatment plant and from ozone-treated river water. Each pathogen was batch grown to stationary phase in sterile water samples, and the concentration of cells produced was measured using flow cytometry. In addition, the fraction of AOC consumed by each pathogen was estimated. Pathogen growth did not correlate with dissolved organic carbon (DOC) concentration and correlated only weakly with the concentration of AOC. Furthermore, the three pathogens never grew to the same final concentration in any water sample, and the relative ratio of the cultures to each other was unique in each sample. These results suggest that the extent of pathogen growth is affected not only by the concentration but also by the composition of AOC. Through this bioassay, PGP can be included as a parameter in water treatment system design, control, and operation. Additionally, a multilevel concept that integrates the results from the bioassay into the bigger framework of pathogen growth in water is discussed. The proposed approach provides a first step for including pathogen growth into microbial risk assessment.Pathogenic bacteria can survive and also grow in low-nutrient aquatic environments, such as surface waters or man-made water treatment systems (2, 17, 30). Studies on pathogen survival and/or die-off (including disinfection) in water are common, but little is known about the fundamental factors governing their growth in the environment (34, 35). Understanding the growth of pathogenic bacteria in aquatic ecosystems is essential for a holistic approach to microbial risk assessment as well as for improving drinking water treatment design and operation.A key factor governing growth of all organisms is nutrient availability. All human pathogens are heterotrophs, utilizing organic compounds as their carbon and energy source. Natural organic matter in water comprises a broad spectrum of many different compounds; it is usually determined as a bulk parameter, such as dissolved organic carbon (DOC). Only a fraction (0.1 to 44%) of this DOC pool is readily available for bacterial growth (18, 33). This bioavailable fraction is quantified using bioassays, such as the biodegradable dissolved organic carbon (BDOC) assay (27) or the assimilable organic carbon (AOC) assay (31). Typically, AOC represents small molecules readily available for growth, whereas BDOC can also include larger molecular compounds, which require predegradation before they can be taken up by microbial cells. Results from both of these assays are commonly used as indicators for bacterial growth potential and have previously been associated with regrowth and biofilm formation in drinking water distribution systems (7, 20, 32).Previous studies have pointed toward an apparent correlation between the concentration of AOC and the presence of enteric bacteria. For example, during two large surveys of drinking water treatment systems across North America, the occurrence (presence/absence) of coliform bacteria was found to be elevated above an AOC concentration of 100 μg liter⁻¹ (4, 21). Other studies also found that AOC concentrations were directly correlated to growth of pathogenic bacteria (30, 34, 35). However, AOC is a bulk parameter, which includes many different substrates (e.g., amino acids, sugars, and fatty acids) readily available for heterotrophic growth. Hence, its composition can differ distinctly, and it is assumed that every aquatic environment carries a complex and unique “fingerprint” of utilizable organic carbon compounds (22). Moreover, the spectrum of growth-supporting substrates (carbon compounds) of individual bacterial strains is specific—a fact also used for the classification of bacteria for taxonomic purposes. This principle has been integrated into conventional AOC assays, where the specific substrate spectrum of different pure cultures can be used to quantify different types of compounds present in water (26, 33). The term “pathogenic bacteria” is a collective term for many different bacterial species that can all cause disease in humans but their individual substrate spectra are unique for each species. Thus, we have hypothesized that the total concentration of AOC alone is not a sufficient parameter for describing the growth potential of pathogenic bacteria; the quality of the available carbon compounds has to be considered as well.There is no existing method that is capable of fractionating organic carbon in a way that allows for the quantification of individual compounds that support growth of specific pathogens. In this study, we have developed a pathogen growth potential (PGP) assay by combining the conventional AOC assay (31) with flow cytometric quantification of bacterial growth (11) and using pathogens as inocula. The PGP assay yields two main results, namely, (i) the extent of pathogen growth, and (ii) the relative fraction of AOC consumed by a pathogen. With this approach, we investigated the growth potential of three model pathogens from three different genera, namely, Escherichia coli O157, Vibrio cholerae O1, and Pseudomonas aeruginosa, in a broad range of water samples, differing considerably in their origin and quality.     

Immunogenicity and Safety in Adults of a New Chromatographically Purified Vero-cell Rabies Vaccine (CPRV): a Randomized, Double-blind Trial with Purified Vero-cell Rabies Vaccine (PVRV)

Recent improvements in chromatographic purification procedures have made it possible to develop a new chromatographically purified rabies vaccine (CPRV) by further purifying the current rabies vaccine prepared from Vero-cell culture (Verorab; Pasteur Mérieux Connaught). The immunogenicity and safety of primary immunization, followed by a booster at one year, with CPRV was compared to that of the purified Vero cell vaccine (PVRV) in a randomized, double-blind study carried out at four veterinary schools in France. A total of 330 healthy, male and female, first-year veterinary students, aged at least 18 years and who required pre-exposure rabies prophylaxis, were enrolled in this study. Included subjects were randomly assigned either CPRV (n = 163) or PVRV (n = 167) to be given as a primary immunization series of three intramuscular injections (D0, D7, D28), followed by a booster after 1 year (D365). Blood samples for serological analysis were taken at D0 (before first injection), D28, D42, D180, D365 (before booster) and D379. All subjects developed a strong immune response to the primary series, and at D42, all subjects had seroconverted for rabies neutralizing antibody (serum titre > or = 0.5 IU/ml). The rabies virus-neutralizing antibody GMT value at D42 in the CPRV group (23.0 IU/ml) was non-inferior to that in the PVRV group (29.6 IU/ml), according to a one-sided non-inferiority test. While antibody titres tended to decrease over the period of follow-up, at D365 (before booster), 97.5% subjects in the CPRV group and 98.8% of subjects in the PVRV group remained seroconverted. After booster, although the rabies antibody GMT value in the CPRV group was lower than that in the PVRV group, all subjects in both groups were seroconverted, and the difference is probably not clinically important. The incidence of local and systemic reactions tended to decrease with each dose during the primary immunization series, followed by a slight increase after booster (significant time-effect in an exploratory logistic regression analysis). Although mild or moderate local reactions tended to be more frequent after injection with CPRV compared to PVRV, systemic reactions were reported less often (significant group-effects in exploratory logistic regression analyses). One serious adverse event possibly related to vaccine occurred during this study (severe asthenia after the third dose of PVRV). This comparative study in healthy young adults demonstrates that the new chromatographically purified rabies vaccine is as immunogenic as PVRV, and seems to be associated with fewer systemic reactions.     

Paranapiacabaea paulista,a new genus and species of Sematophyllaceae from southeastern Brazil

A new moss,Paranapiacabaea paulista, is described from the Serra do Mar of the state of São Paulo, Brazil. It is characterized by erect, narrowly flask-shaped capsules with a pale peristome, blunt, papillose exostome teeth, and an endostome with segments longer than the exostome teeth. Its relationships toDonnellia, Pterogoniopsis, andMaguireella are discussed. The combinationMaguireella vulpina (Mont.) Buck is validated.