Endocrine and physiological responses of hatchling American kestrels (Falco sparverius) following embryonic exposure to technical short-chain chlorinated paraffins (C10-13).

Short chain chlorinated paraffins (SCCPs) are complex mixtures of polychlorinated n-alkanes, shown to bioaccumulate but with unknown effects in wild birds. The present study examined development-related effects of SCCPs on captive American kestrels (Falco sparverius) treated in ovo on embryonic day (ED) 5 by injection with technical Chloroparaffin® (C10-13, 55.5% Cl) at environmentally relevant nominal (measured) concentrations of 10 (10), 50 (29) or 100 (97) ng ΣSCCP/g egg ww, and artificially incubated until hatching (ED27-ED29). The SCCP concentrations measured in the yolk sacs of the hatchling kestrels bracketed concentrations reported in the eggs of wild birds. Uptake and deposition of these SCCPs differed between male and female hatchlings, with only males showing differences in SCCP concentrations, being highest in the high-dose males than each of the other male groups. Embryonic exposure to SCCPs suppressed glandular total thyroxine (TT4) (20-33%) and reduced circulating triiodothyronine (TT3) (37-40%) in male hatchlings only when compared to control males, but had no effect on glandular TT3 or circulating TT4 in male or female kestrels. Histological assessments of thyroid glands showed that both sexes experienced significant structural changes indicative of gland activation. These thyroid glandular changes and the variations in SCCP concentrations were related to circulating TT3 in female hatchlings. Hepatic deiodinase enzyme (D1, D2) activities were stable and no SCCP-related changes were observed in hatching success, hatchling size, or immune organ size. However, several of the thyroid function indicators were correlated with hatchling size and smaller bursas and spleens, possibly indirectly through SCCP-induced changes in thyroid function. Because changes in thyroid function were evident at concentrations measured in wild bird eggs, similar changes may occur in wild nestlings. The potential impact of these changes on thyroid-mediated growth and survival in wild birds requires further investigation.

Inactivation of the bacterial pathogens Staphylococcus pseudintermedius and Acinetobacter baumannii by butanoic acid.

AIMS: This study was performed to evaluate the efficacy of butanoic acid against bacterial pathogens including Acinetobacter baumannii and Staphylococcus pseudintermedius. METHODS AND RESULTS: Vegetative bacteria were exposed to butanoic acid in vitro and log reduction was quantified using viable count assays. The maximum (8 and 9) log inactivation was determined by qualitatively assaying for growth/no-growth after a 48-h incubation (37°C). Membrane integrity after exposure to butanoic acid was determined by propidium iodide staining, scanning electron microscopy, membrane depolarization and inductively coupled plasma analysis. Cytosolic pH was measured by 5-(6-)carboxyfluorescein succinimidyl ester. CONCLUSIONS: Inhibitory concentrations of butanoic acid ranged between 11 and 21 mmol l-1 for Gram-positive and Gram-negative species tested. The maximum log reduction of A. baumannii was achieved with a 10-s exposure of 0·50 mol l-1 of butanoic acid. Staphylococcus pseudintermedius required 0·40 mol l-1 of butanoic acid to achieve the same level of reduction in the same time period. Inactivation was associated with membrane permeability and acidification of the cytosol. SIGNIFICANCE AND IMPACT OF THE STUDY: Antibiotic resistance among bacterial pathogens necessitates the utilization of novel therapeutics for disinfection and biological control. These results may facilitate the development of butanoic acid as an effective agent against a broad-spectrum of antibiotic-resistant bacterial pathogens.

Randomly ordered addressable high-density optical sensor arrays.

Array-based sensors provide an architecture for multianalyte sensing. In this paper, we report a new approach for array fabrication. Sensors are made by immobilizing different reactive chemistries on the surfaces of microspheres. Sensor arrays are prepared by randomly distributing a mixture of microsphere sensors on an optical substrate containing thousands of micrometer-scale wells. The sensors occupy a different location from array to array; thus the identity of each sensor is ascertained and registered on the detector using encoding schemes, rather than by a predetermined location in the array. The approach thereby shifts the demand from fabrication to signal processing. The availability of commercial image analysis software makes such a shift both cost-effective and time efficient.

The theory of natural capsular contraction around breast implants and how to prevent it.

Many articles have described various causes of capsular contraction around breast implants. However, even when these causes are not present, an implanted breast that is soft postoperatively may still become firm later. Such cases can be explained by the theory of natural capsular contracture, based on the observation that the human body will obliterate cavities anywhere within it unless an obturator is present to prevent it. The speed of contraction is described in this paper by presentation of clinical cases. To maintain an adequate cavity at the breast implant site, we have designed a series of exercises, using the implant as the obturator, which have markedly reduced the incidence of firm breasts.

Reaction to silicone implants in the guinea pig.

Many papers have been published on the lack of reaction around silicone implants both in the experimental animal and the human. A study with human silicone implants with silicone gel interior shows loss of the silicone fluid from intact silicone sac. A solid silicone disc subjected to 5 pounds weight for one week loses silicone to the underlying paper. In the guinea pig, some capsules surrounding solid silicone implants, silicone sacs with saline, and silicone sac with silicone gel show vacuole or amorphous materials (silicone) with a thickening of the capsule and associated inflammatory reaction. These vacuoles or amorphous material resembles the silicone found in capsules around intact human silicone jell prosthesis. The presence of silicone with associated thickening of the capsule and inflammatory reaction may be one cause of firmness in the human after breast augmentation by silicone implants.