Adherence of Pseudomonas aeruginosa to tracheal epithelium.

Adherence of mucoid and nonmucoid strains of Pseudomonas aeruginosa to tracheal epithelium was studied with a perfused-trachea model. The species specificity of adherence was studied by infecting tracheas from hamsters, guinea pigs, or mice. Perfused tracheas from hamsters were infected with strains of P. aeruginosa in the presence of various sugars, lectins, cations, or charged polymers. Adherence of mucoid strains of P. aeruginosa was greatest for guinea pigs; that for hamsters and mice was approximately the same. Nonmucoid strains did not adhere well to epithelium from any of the species tested. N-Acetylglucosamine, galactose, and N-acetylneuraminic acid were the best inhibitors of adherence of mucoid strains of P. aeruginosa. Phaseolus vulgaris agglutinin and Arachis hypogaea agglutinin enhanced adherence of mucoid strains. Adherence of mucoid strains was also enhanced by the presence of Ca2+ in the incubation medium. Poly-L-lysine, poly-L-aspartic acid, and polyglycine inhibited adherence of a mucoid strain by 96, 86, and 52%, respectively. In general, the adherence of nonmucoid strains was not affected. The results indicate that carbohydrates are involved in the interaction of mucoid strains of P. aeruginosa with tracheal cells and that divalent cations may enhance this interaction. The lectin data show that lectins can interact with the mucoid organisms and the host and suggest that lectins may play a role in the adhesion process.     

Characterization of Mutations Contributing to Sulfathiazole Resistance in Escherichia coli

A sulfathiazole-resistant dihydropteroate synthase (DHPS) present in two different laboratory strains of Escherichia coli repeatedly selected for sulfathiazole resistance was mapped to folP by P1 transduction. The folP mutation in each of the strains was shown to be identical by nucleotide sequence analysis. A single C→T transition resulted in a Pro→Ser substitution at amino acid position 64. Replacement of the mutant folP alleles with wild-type folP significantly reduced the level of resistance to sulfathiazole but did not abolish it, indicating the presence of an additional mutation(s) that contributes to sulfathiazole resistance in the two strains. Transfer of the mutant folP allele to a wild-type background resulted in a strain with only a low level of resistance to sulfathiazole, suggesting that the presence of the resistant DHPS was not in itself sufficient to account for the overall sulfathiazole resistance in these strains of E. coli. Additional characterization of an amplified secondary resistance determinant, sur, present in one of the strains, identified it as the previously identified bicyclomycin resistance determinant bcr, a member of a family of membrane-bound multidrug resistance antiporters. An additional mutation contributing to sulfathiazole resistance, sux, has also been identified and has been shown to affect the histidine response to adenine sensitivity displayed by these purU strains.     

Do patients with borderline personality disorder belong to the bipolar spectrum?

BACKGROUND: This report examines clinical indicators for bipolarity in a cohort of patients suffering from Borderline Personality Disorder (BPD). METHODS: The study was conducted in the Cornell-Westchester Hospital, famed for its expertise in BPD. To avoid biasing our sample, we excluded all BPD patients who were active patients in our anxiety and mood disorders program. Through the use of both open clinical interviews and standardized diagnostic interviews (SCID), borderline patients were examined for evidence of bipolarity by five indicators: history of spontaneous mania, history of spontaneous hypomania, bipolar temperaments, pharmacologic response typical of bipolar disorder, and a positive bipolar family history. RESULTS: Depending on the level of bipolar disorder from the most rigorous (mania) to the most 'soft' (bipolar family history), between 13 and 81% of borderline patients showed signs of bipolarity. Based on what the emerging literature supports as rigorously defined bipolar spectrum (bipolar I and II), we submit that at least 44% of BPD belong to this spectrum; adding hypomanic switches during antidepressant pharmacotherapy, the rate of bipolarity in BPD reaches 69%. As expected from this formulation, most responded negatively to antidepressants (e.g. hostility and agitation) and positively to mood stabilizers. LIMITATIONS: Small sample size and retrospective gathering of data on treatment response. CCONCLUSION: Patients with BPD more often than not exhibit clinically ascertainable evidence for bipolarity and may benefit from known treatments for Bipolar Spectrum Disorders. Large scale, systematic treatment studies with mood stabilizers are indicated.     

A review of recent progress in polymeric electrospun nanofiber membranes in addressing safe water global issues

With rapid advancement in water filtration materials, several efforts have been made to fabricate electrospun nanofiber membranes (ENMs). ENMs play a crucial role in different areas of water treatment due to their several advantageous properties such as high specific surface area, high interconnected porosity, controllable thickness, mechanical robustness, and wettability. In the broad field of water purification, ENMs have shown tremendous potential in terms of permeability, rejection, energy efficiency, resistance to fouling, reusability and mechanical robustness as compared to the traditional phase inversion membranes. Upon various chemical and physical modifications of ENMs, they have exhibited great potential for emerging applications in environment, energy and health sectors. This review firstly presents an overview of the limiting factors influencing the morphology of electrospun nanofibers. Secondly, it presents recent advancements in electrospinning processes, which helps to not only overcome drawbacks associated with the conventional electrospinning but also to produce nanofibers of different morphology and orientation with an increased rate of production. Thirdly, it presents a brief discussion about the recent progress of the ENMs for removal of various pollutants from aqueous system through major areas of membrane separation. Finally, this review concludes with the challenges and future directions in this vast and fast growing area.

This review provides an overview of recent advances and developments in electrospinning technology and the recent progress and applications of electrospun nanofiber membranes to expel various pollutants from water.     

Bioavailability of Alpha-Linolenic Acid in Subjects after Ingestion of Three Different Forms of Flaxseed

Background: Dietary flaxseed may have significant health-related benefits due to its high content of the omega-3 fatty acid, alpha-linolenic acid (ALA). However, before extensive work can be undertaken in clinical populations to determine its efficacy, basic information on ALA bioavailability from flaxseed and the physiological effects of its ingestion need to be examined.

Objective: The purpose of this study, therefore, was to determine the bioavailability of ALA when the flaxseed was ingested in the form of whole seed, milled seed or as flaxseed oil.

Design: The flaxseed components (30 g of seed or 6 g of ALA in the oil) were baked into muffins for delivery over a 3 month test period in healthy male and female subjects.

Results: Flaxseed ingestion over a 1 month period resulted in significant (P = 0.005) increases in plasma ALA levels in the flaxseed oil and the milled flaxseed supplemented groups. The former group had significantly (P = 0.004) higher ALA levels than the milled flaxseed group. The subjects supplemented with whole flaxseed did not achieve a significant (P > 0.05) increase in plasma ALA levels. An additional two months of flaxseed ingestion did not achieve significantly higher levels of plasma ALA in any of the groups. However, no significant increase was detected in plasma eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) levels in any of the flax-fed groups. There were no changes in plasma cholesterol or triglycerides or in platelet aggregation at any time point in any of the groups. Subjects in all of the groups exhibited some symptoms of gastro-intestinal discomfort during the early stages of the study but these disappeared in the oil and milled seed groups. However, compliance was a problem in the whole flaxseed group.

Conclusion: In summary, ingestion of flax oil and milled flaxseed delivered significant levels of ALA to the plasma whereas whole flaxseed did not. Whole seed and oil preparations induced adverse gastrointestinal effects within 4 weeks and these were severe enough to induce the withdrawal of some subjects from these two groups. No one withdrew from the group that ingested milled flaxseed and, therefore, may represent a good form of flaxseed to avoid serious side-effects and still provide significant increases in ALA to the body.