Polybrominated diphenyl ethers in house dust and clothes dryer lint

Few studies have measured the flame retardants polybrominated diphenyl ethers (PBDEs) in the indoor environment. Here, we report measurements of PBDEs in house dust samples collected from the Washington, D.C. metropolitan area in the United States. Dust samples were analyzed for 22 individual PBDE congeners and our results found PBDEs present in every sample. Concentrations of total PBDEs ranged from 780 ng/g dry mass to 30 100 ng/g dry mass. The dominant congeners observed in the dust samples were congeners associated with the pentaBDE and decaBDE commercial mixtures. Ancillary data were collected on the homes and examined for any correlations with total PBDE concentrations. No correlations were observed with year of house construction, type of flooring (i.e., hardwood vs carpet) or the number of television sets or personal computers in the home. However, a significant inverse correlation (p < 0.05) was observed between the area of the home and the contribution of BDE 209 to the total PBDE concentration in dust. Using estimates of inadvertent dust ingestion (0.02-0.2 g/day) by young children (ages 1-4), we estimate ingestion of total PBDEs to range from 120 to 6000 ng/day. Clothes dryer lint was also sampled and analyzed for PBDEs from five of the homes and were present in all five samples ranging from 480 to 3080 ng/g dry mass. This study demonstrates that PBDEs are prevalent at relatively high concentrations within homes where people, and particularly young children, may be susceptible to exposure.     

Application of an X-ray microscopy technique to evaluate tissue-engineered bone-scaffold constructs

Elemental composition and structural analysis are important considerations in evaluating osseous matrix formation in tissue-engineered bone constructs. Using X-ray spectroscopy techniques, such as the X-ray scanning analytical microscope (XSAM), enables the mapping of elements with simultaneous structural imaging. The aim of this study was to evaluate the feasibility of this microscopy technique to analyze tissue-engineered samples. Fused deposition modeling (FDM), a rapid prototyping technology, was used to fabricate 3-D scaffolds made of polycaprolactone (PCL)–hydroxylapatite (HA) (90/10 wt.%). The scaffolds had a regular architecture and the honeycomb-like pores were fully interconnected with a total matrix porosity of 70%. Biopsies of human calvarial corticocancellous bone were harvested and a primary explant system of the morcellized grafts was established within the PCL–HA constructs.

Tissue constructs were cultured in vitro for 3 weeks and then implanted into the back of Balb C nude mice. Grafts were explanted after 17 weeks and tissue formation was assessed via XSAM and CT scan and histology.

Outgrowth from osteoblasts from the bone chips started after 2 weeks in culture, with cells migrating radially into the composite constructs. Osteocalcin levels showed an increasing tendency during the 3-week culture period. After 17 weeks in vivo, areas of ectopic bone formation could be detected throughout the whole construct, compared to the control implants where only fibrous tissue formation was present. In the XSAM, calcium- and phosphorus-enriched bands presented a relatively even distribution with some dense spots. Quantitative elemental analysis revealed an average X-ray intensity of 131 cps for calcium in a mapped area of 2 mm². Trichrome Goldner staining showed good vascularization as well as irregular osteoid formation and mineralization of the newly formed woven bone-like tissue.

In this study, we were able to show that the XSAM is a useful analytical technique which enabled us to trace elements simultaneously and provides structural image with mapping information in tissue-engineered samples.     

Shrinking spinal cord following transverse myelopathy in a patient with systemic lupus erythematosus and the phospholipid antibody syndrome

A 38-year-old woman with systemic lupus erythematosus and the phospholipid antibody syndrome was admitted because of rapidly evolving symptoms consistent with a transverse myelopathy at the TH9/10 level. Magnetic resonance imaging (MRI) showed slight diffuse swelling and increased signal intensity of the spinal cord. She was treated with high dose methylprednisolone plus azathioprine and aspirin. Four months later she had achieved almost complete remission with minimal residual sphincter disturbances. Despite the clinical recovery, repeated MRI at 4 months and 4 years showed diffuse and irreversible atrophy of the entire spinal cord.     

Poly(-caprolactone) films as a potential substrate for tissue engineering an epidermal equivalent

A preliminary cell culture study of human keratinocytes (HK) on solvent-cast and biaxially stretched poly(-caprolactone) (PCL) films was carried out. Cell attachment and proliferation on solvent-cast films was compared with commercially available wound dressings while cell attachment, proliferation and viability on biaxially stretched films were assessed using light, confocal laser and scanning electron microscopy (CLM and SEM). Solvent-cast sheets were biaxially stretched to produce 5–15-μm-thick films. Biaxially stretched films were shown to be better epidermal substrates due to the better flexibility and strength to mass ratio than solvent-cast sheets. Images obtained showed that the cells attached and proliferated on poly(-caprolactone) films, and maintained high percentage of viability throughout the culture period. Keratinocytes exhibited healthy cobblestone morphology and proliferated as continuous monolayers. These results indicated that poly(-caprolactone) films would support the attachment and proliferation of human keratinocytes and have the potential to be applied as a matrix material for tissue engineering an epidermal equivalent.     

Effects of chronic estradiol treatment on delayed spatial alternation and differential reinforcement of low rates of responding.

Estrogens have been shown to both enhance and impair cognitive function depending on several factors, including regimen of hormone treatment, age of subject, and task attributes. In rodent models, estradiol tends to enhance spatial learning and impair response or cued learning, but effects on executive functions are less well-studied. In this experiment, spatial working memory and response inhibition were tested using delayed spatial alternation (DSA) and differential reinforcement of low rates of responding (DRL) tasks in ovariectomized rats that were given chronic estradiol via Silastic implants resulting in serum estradiol concentrations of 86.2 ± 8.2 (SEM) pg/ml. Rats were tested for 25 days DSA with variable delays of 0, 3, 6, 9, and 18 seconds between lever presentations, followed by 30 days on a DRL-15s operant schedule. Estradiol-replaced rats showed a significantly lower proportion of correct responses on the DSA task compared to vehicle-implanted ovariectomized animals. On DRL, estradiol-treated rats showed a lower ratio of reinforced to nonreinforced presses. These data suggest that chronic estrogen exposure may impair rats' abilities on measures of executive function including working memory and response inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Efficient gene transfer to human squamous cell carcinomas by the herpes simplex virus type 1 amplicon vector

We determined the diagnostic value of the EEG in young children with Angelman syndrome (AS) and Rett syndrome (RS). EEGs, recorded before 5 years of age, of 10 patients with AS, 10 with RS and 10 with mental retardation of other origin were studied blindly by two examiners for the presence of the following items: (A) 4-6 Hz rhythmic activity of over 200 microV; (B) 2-3 Hz frontal activity of 200-500 microV; (C) posterior spikes; (D) triphasic frontal waves; (E) central and/or centro-temporal spike-wave complexes; and (F) other epileptic discharges. Based on these items the EEGs were scored as AS (A-D); RS (E-F); or other. Examiners never made a mistake between AS and RS. One examiner labeled 6 of 10 AS cases correctly, the other 5; 4 (5) were characterized as 'other.' In RS cases 5 were labeled as 'other' by the first examiner and 3 by the second one. We conclude that EEG patterns of AS and RS are sufficiently different to help differentiate between AS and RS at a young age, which has a bearing on genetic counseling.     

Molecular support for field cancerization in the head and neck

BACKGROUND: Two competing concepts, field cancerization and micrometastatic lesions, have been postulated to account for the high frequency of second primary tumors and multicentric dysplasia in patients with head and neck carcinoma. METHODS: To provide insight into this process, the authors examined histologically normal mucosa and dysplastic tissue adjacent to invasive tumor for loss of heterozygosity (LOH) at three commonly deleted loci. Tissues from 21 patients with carcinoma of the oral cavity and oropharynx were identified and verified by a pathologist to contain histologically normal mucosa, dysplasia, and adjacent invasive squamous cell carcinoma. Each specimen was analyzed for LOH at D9S171 (9p21), D3S1007 (3p21.3-22), and D3S1228 (3p14). RESULTS: Of the 21 patients, 19 had adequate DNA for analysis. Seventeen patients were heterozygous at one or both of the 3p sites and LOH occurred in 6 of 17 invasive tumor specimens, 1 of 17 dysplasia specimens, and in none of the mucosal specimens. LOH at 9p21 occurred in 11 of 13 informative specimens of invasive tumor, 8 of 13 dysplasia specimens, and 6 of 13 normal mucosa specimens. However, one case that did not have 9p deletion in the tumor demonstrated LOH in the mucosa and two cases had LOH in both the tumor and mucosa but with deletion of the opposite allele. CONCLUSIONS: These data suggest that 9p21 but not 3p14 or 3p21 deletions occur in the absence of histologic changes. In two cases preinvasive and invasive lesions that apparently were an example of histologic progression contained disparate genetic events, calling into question the use of adjacent dysplasia as a model for premalignant lesions.     

Evaluating headspace component vapor-time profiles by solid-phase microextraction with external sampling of an internal standard

The vapor-time profiles of explosive materials are of valuable interest to Homeland Security, providing critical information that can aid in the detection of explosive-containing devices. An approach is described that achieves reproducible characterization of volatile components as a function of time based on comparison of the sample response to an externally sampled internal standard (ESIS). Utilizing nonequilibrium solid-phase microextraction (SPME) measurements, this SPME-ESIS technique improves reproducibility (reported as percent relative standard deviation) of vapor-time profiles by approximately an order of magnitude and allows for an equitable comparison of the target compound between diverse materials. Two odorants associated with canine detection of explosives, 2-ethyl-1-hexanol and 2,4-dinitrotoluene, are used to optimize parameters for the SPME-ESIS technique.