Decisive Role of Polymer-Bovine Serum Albumin Interactions in Biofilm Substrates on "Philicity" and Extracellular Polymeric Substances Composition.

Formation of extracellular polymeric substances (EPS) is a crucial step for bacterial biofilm growth. The dependence of EPS composition on growth substrate and conditioning of the latter is thus of primary importance. We present results of studies on the growth of biofilms of two different strains each, of the Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae, on four polymers used commonly in indwelling medical devices ─polyethene, polypropylene, polycarbonate, and polytetrafluoroethylene─immersed in bovine serum albumin (BSA) for 24 h. The polymer substrates are studied before and after immersing in BSA for 9 and 24 h, using contact angle measurement (CAM) and field emission scanning electron microscopy (FE-SEM) to extract, respectively, the "philicity" φ (defined as -cos θ, where θ is the contact angle of the liquid on the solid at a particular temperature and ambient pressure) and spatial Hirsch parameter H (defined from the relation F(r) ∼ r2H, where F(r) is the mean squared density fluctuation at the sample surface). H = 0.5, <0.5, or >0.5 signifies no correlation, anticorrelation, and correlation, respectively. The substrates are seen to transform from large hydrophobicity to near amphiphilicity with the formation of a BSA conditioning surface layer, and the H-values distinguish the length scales of 100, 500, and 2000 nm, with the anticorrelation increasing with length scale. Biofilms of E. coli did not grow on bare PTFE and HDPE substrates. Biofilms grown on BSA-covered surfaces are studied with CAM, FE-SEM, Fourier transform infrared (FTIR), and surface-enhanced Raman spectroscopy (SERS). Both spectra and φ-values were independent of bacterial species but dependent on the polymer, while H-values show some bacterial variation. Thus, EPS composition and wetting properties of the corresponding bacterial biofilms seem to be decided by the interaction of the conditioning BSA layer with the specific polymer substrate.

The Effect of Depo Medroxyprogesterone Acetate (DMPA) on Cerebral Food Motivation Centers: A Pilot Study using Functional Magnetic Resonance Imaging.

OBJECTIVE: The primary objective is to examine activation of food motivation centers in the brain before and 8 weeks after depo medroxyprogesterone acetate (DMPA) administration. STUDY DESIGN: This prospective experimental pilot study examined the effects of DMPA on food motivation centers utilizing functional magnetic resonance imaging (fMRI) in eight nonobese, ovulatory subjects. fMRI blood oxygen level dependent (BOLD) signal was measured using a 3-Tesla Scanner while participants viewed images of high-calorie foods, low-calorie foods and nonfood objects. fMRI scans were performed at baseline and 8 weeks after participants received one intramuscular dose of DMPA 150 mg. fMRI data were analyzed using the FMRIB Software Library. Changes in adiposity and circulating leptin and ghrelin levels were also measured. RESULTS: There was a greater BOLD signal response to food cues in brain regions associated with food motivation (anterior cingulate gyrus, orbitofrontal cortex) 8 weeks after DMPA administration compared to baseline (z>2.3, p<.05 whole-brain analysis clustered corrected). No statistically significant change was detected in circulating leptin or ghrelin levels or fat mass 8 weeks after DMPA administration. CONCLUSION: Analysis of differences in food motivation may guide the development of interventions to prevent weight gain in DMPA users. IMPLICATIONS: These data support a neural origin as one of the mechanisms underlying weight gain in DMPA users and may guide future research examining weight gain and contraception.

Morphology and ion-conductivity of gelatin-LiClO4 films: fractional diffusion analysis.

Biopolymers are expected to replace synthetic polymers in the quest for cost-effective, environment friendly, and pollution free technology. We report here a study on gelatin films with different concentrations of lithium perchlorate, which may be a candidate for electrolyte material in solid polymer batteries. Morphology studies and impedance spectroscopy both are done on the same set of samples. We study the microstructure of the film by SEM and try to see if a correlation between impedance spectroscopy results and features of gel morphology can be identified. A network structure is revealed in the SEM images where details of the network parameters appear to depend on the salt fraction. Analysis of the impedance measurements is done using a physically meaningful model based on material properties instead of the usual equivalent circuit formalism, where circuit elements are difficult to interpret. We find that anomalous diffusion of charge carriers plays an important role; this is incorporated through a fractional calculus approach.

Preoperative diagnosis of ovarian malignancy: preliminary results of the use of 3-dimensional vascular ultrasound.

OBJECTIVE: To estimate the accuracy of 3-dimensional (3D) vascular ultrasound in the preoperative assessment of pelvic masses for malignancy. METHODS: We performed a chart review of 66 patients who underwent 3D ultrasound for pelvic masses. Each mass was preoperatively judged to be benign or malignant based upon a study of vascularity within an ovarian mass using 3D ultrasound. Masses with orderly vascular architecture were categorized as probably benign, and masses with chaotic vascular patterns were categorized as malignant. The predictive value of 3D vascular ultrasound was compared with that of 2-dimensional ultrasound and cancer antigen 125 as a predictor of malignancy. RESULTS: Among the 66 patients examined, 34 underwent a documented surgical intervention. Of those 34 patients, 10 had primary malignant neoplasms including 2 with low-malignant potential tumors. Suspicious 3D vascular ultrasound findings predicted malignant neoplasm in 10 patients. Two patients had recurrent cancer; however, only 1 had a suspicious ultrasound finding. There was 1 case of a low-malignant potential tumor without a suspicious ultrasound finding. Excluding the recurrent cancers and the observed patients, the positive predictive value (PPV) and the negative predictive value (NPV) of 3D vascular ultrasound were 100% and 95%, respectively. The PPV and the NPV of 2-dimensional ultrasound in predicting malignancy were 37% and 100%, respectively. An abnormal level of cancer antigen 125 had a PPV and an NPV of 73% and 83%, respectively, in this patient population. CONCLUSIONS: In this preliminary and observational study, 3D ultrasound examination of vascular architecture was discriminatory in distinguishing benign ovarian masses from malignancy. Chaotic vascular architecture correlated with malignancy in this group of high-risk patients.