Raoult's law-based method for determination of coal tar average molecular weight

A Raoult's law-based method for determining the number average molecular weight of coal tars is presented. The method requires data from two-phase coal tar/water equilibrium experiments, which readily are performed in environmental laboratories. An advantage of this method for environmental samples is that it is not impacted by the small amount of inert debris often present in coal tar samples obtained from contaminated sites. Results are presented for 10 coal tars from nine former manufactured gas plants located in the eastern United States. Vapor pressure osmometry (VPO) analysis provided similar average molecular weights to those determined with the Raoult's law-based method, except for one highly viscous coal tar sample. Use of the VPO-based average molecular weight for this coal tar resulted in underprediction of the coal tar constituents' aqueous concentrations. Additionally, one other coal tar was not completely soluble in solvents used for VPO analysis. The results indicate that the Raoult's law-based method is able to provide an average molecular weight that is consistent with the intended application of the data (e.g., modeling the dissolution of coal tar constituents into surrounding waters), and this method can be applied to coal tars that may be incompatible with other commonly used methods for determining average molecular weight, such as vapor pressure osmometry.     

Mechanism(s) of increased vascular cell adhesion on nanostructured poly(lactic-co-glycolic acid) films

Studies have shown that poly(lactic-co-glycolic acid) (PLGA) films with nanometer surface features promote vascular endothelial and smooth muscle cell adhesion. The objective of this in vitro research was to begin to understand the mechanisms behind this observed increase in vascular cell adhesion. Results provided evidence that nanostructured PLGA adsorbed significantly more vitronectin and fibronectin from serum compared to conventional (or those not possessing nanometer surface features) PLGA. When separately preadsorbing both vitronectin and fibronectin, increased vascular smooth muscle and endothelial cell density was observed on nanostructured (compared to conventional) PLGA. Additionally, blocking of cell-binding epitopes of fibronectin and vitronectin significantly decreased vascular cell adhesion on nanostructured (compared to conventional) PLGA. For this reason, results of the present in vitro study demonstrated that cell adhesive proteins adsorbed in different quantities and altered bioactivity on nanostructured compared to conventional PLGA topographies, which (at least in part) may account for the documented increased vascular cell adhesion on nanostructured PLGA. In this manner, this study continues to provide evidence for the promise of nanostructured PLGA in vascular tissue engineering applications.     

Amygdalar NMDA receptors control the expression of associative reflex facilitation and three other conditional responses

Four conditional responses (CRs) were measured in rats implanted with bilateral cannulas in the basolateral nuclear complex of the amygdala (BLA). During retention testing in either the original training context or a shifted context, BLA was infused with artificial cerebral spinal fluid (ACSF) or ACSF containing an N-methyl-D-aspartate receptor antagonist (APV). Regardless of the testing context, APV infusion into BLA completely blocked the expression of conditional eyeblink facilitation and significantly attenuated the expression of conditional freezing, ultrasonic vocalization, and defecation. Discriminant analysis found eyeblink facilitation to be comparable to freezing in predicting group membership (APV vs. ACSF) and both to be better predictors than the other two CRs. The APV effect did not depend on the exact cannula positions within BLA.     

The life and death of oligodendrocytes in vanishing white matter disease

Vanishing white matter disease (VWM) is a progressive cavitating disease of central white matter due to a deficiency of the translation initiation factor eIF2B. Oligodendrocytes appear to be numerically increased in some white matter areas, while decreased in others. We compared oligodendrocytes of cerebral, cerebellar, and pontine white matter from 5 VWM patients with those of age-matched controls by light microscopy and immunohistochemistry using antibodies to activated caspase-3, bak, bax, bcl-2, survivin, and Ki-67, as well as by the TUNEL technique. Oligodendrocytes were identified morphologically and quantified using an ocular grid. We observed statistically significant increases in their densities at all sites; Ki-67-labeled oligodendrocytes were identified in 2 of 5 patients. Apoptotic oligodendrocytes were documented in 3 of 5 patients, while bcl-2 and survivin labeling was observed in 2 of 5 and 2 of 2 patients, respectively. There was a trend toward an increase in apoptotic labeling of oligodendrocytes that was strongest in the cerebrum, the major locus of VWM, in the youngest and most severely affected patients. These data conclusively demonstrate increased oligodendrocytic densities in VWM; the increase is not an artifact of white matter contraction. Our data also document that oligodendrocytes undergo apoptosis, perhaps in conjunction with major neurologic crises, and that a subset of oligodendrocytes are able to persist and proliferate. Conflicting proliferative, cell-death, and survival signals impact the oligodendrocytes of VWM.     

Peptide ligands targeting integrin alpha3beta1 in non-small cell lung cancer

Lung cancer is one of the most common cancers and is the leading cause of cancer death. We wish to identify peptide ligands for unique cell surface receptors of non-small lung cancer with the hope of developing these ligands as diagnostic and therapeutic agents. Using the method of 'one-bead one-peptide' combinatorial chemistry, a library of random cyclic octapeptides was synthesized on polystyrene beads. This library was used to screen for peptides that promoted attachment of lung adenocarcinoma cells employing a 'cell-growth-on-bead' assay. Consensus peptide sequences of cNGXGXXc were identified. These peptides promoted cell adhesion by targeting integrin alpha3beta1 over-expressed in non-small lung cancer cells. These peptide beads can be applied to capture cancer cells in malignant pleural fluid for purpose of diagnosis of lung cancer.     

The predictability of infant visual-evoked response testing on future visual acuity

We reviewed the records of 27 infants with abnormal eye examinations and visual-evoked response (VER) testing (mean age, 10.5 months) who subsequently underwent a long-term follow-up ophthalmology examination (mean duration, 41 months). The infants were initially diagnosed with various ocular disorders including cortical blindness (eight), optic nerve hypoplasia (six), congenital cataract (two), and retinopathy of prematurity (one). Standard optotype visual-acuity determinations were available in the follow-up records of 11 children (21 eyes), and fixation behavior was obtained in the remaining 16 children (32 eyes). Results revealed that pattern-reversal VER P1 latency was predictive (87%) of whether visual acuity was equal to (or better than) or worse than 20/100 and whether a patient would have good fixation behavior (fix and follow, FF) or poor fixation (no FF) (86%) (P less than .001). Although flash VER P1 latency was also predictive of later visual acuity or good fixation (73%), it was not statistically significant. Pattern VER P1 amplitude and flash VER P1 amplitude were not predictive of later visual function. The predictive power of pattern VER P1 latency for later visual function probably relates to its reflection of macular function and low variability. An analysis of the variability of each of the four VER factors in normal infants (n = 50) indicated that pattern VER P1 latency was the least variable, and consequently most sensitive, VER factor for detecting and quantifying pathology. Overall, the results of this retrospective study suggest that pattern VER P1 latency may have important predictive power for later visual function in infants with an initially abnormal ophthalmologic examination.