Adsorption study of nonionic surfactants on polyester fibers

An adsorption study of a series of nonionic surfactants on polyester fiber was performed to determine the relative importance of sub-strate affinity in the detergency process. The fiber used in this study was a multifilament polyester yarn. Because of the relatively low surface area/g of the yarn, analytical methods for detecting the depletion of surfactant due to adsorption have to be extremely sensitive. One qualitative technique used was streaming potential measurements. The electrokinetic effect, which the streaming poten-tial measures, depends on the nature of the electrical double layer at the fiber/solution interface. The modification of the streaming potential indicates that the extent of surfactant adsorption onto the fiber surface is very similar for the nonionic surfactants studied. A very sensitive, quantitative analytical technique, which can only be used for surfactants with an appropriate chromophore, is ultraviolet (UV) spectroscopy. The UV study showed that the adsorption of the nonylphenol ethoxylate onto the polyester is Langmuirian with the adsorption plateau occurring at the critical micelle concentra-tion. For alcohol ethoxylates without a UV chromophore, con-venient quantification at the ppm level represents a difficult analyt-ical problem. In this work, total carbon analysis was developed as a sensitive analytical tool for surfactant determination. Agreement between the UV and total carbon data for the nonylphenol ethox-ylate was quite good. The relevance of the data to the detergency process is discussed.     

Mitosene-DNA adducts. Characterization of two major DNA monoadducts formed by 1,10-bis(acetoxy)-7-methoxymitosene upon reductive activation

Reductive activation of racemic 1,10-bis(acetoxy)-7-methoxymitosene WV15 in the presence of DNA, followed by enzymatic digestion and HPLC analysis, revealed the formation of various DNA adducts. Reduction is a necessary event for adduct formation to occur. This reductive activation was performed under hypoxic conditions in various ways: (1) chemically, using a 2-fold excess of sodium dithionite (Na2S2O4), (2) enzymatically using NADH-cytochrome c reductase, (3) electrochemically on a mercury pool working electrode, and (4) catalytically, using a H2/PtO2 system. Five different mitosene-DNA adducts were detected. These adducts were also present when poly(dG-dC) was used instead of DNA, but were absent with poly(dA-dT). All were shown to be adducts of guanine. Reduction of 1, 10-dihydroxymitosene WV14 in the presence of DNA did not result in detectable adduct formation, demonstrating the importance of good leaving groups for efficient adduct formation by these mitosenes. Finally, two of the adducts were isolated and their structures elucidated, using mass spectrometry, 1H NMR and circular dichroism (CD). The structures were assigned as the diastereoisomers N2-(1"-n-hydroxymitosen-10"-yl), 2'-deoxyguanosine (n = alpha or beta). These type of adducts, in which the mitosene C-10 is covalently bonded to the N-2 of a guanosylic group, are different from the well-known mitomycin C 2'-deoxyguanosine monoadducts, that is linked via the mitomycin C C-1 position, demonstrating that the order of reactivity of the C-1 and C-10 in these mitosenes is reversed, as compared to mitomycin C. The 7-methoxy substituent of WV15 is a likely factor causing this switch. Evidence is presented that the 7-substituent of mitosenes also influences their DNA alkylation site. Adducts 4 and 5 represent the first isolated and structurally characterized covalent adducts of DNA and a synthetic mitosene.     

The dynamics of prostate specific antigen in hormone refractory prostate carcinoma: an analysis of cancer and leukemia group B study 9181 of megestrol acetate

BACKGROUND: Although many physicians measure serum prostate specific antigen (PSA) during the follow-up of patients with hormone refractory prostate carcinoma (HRPC), little has been done to formalize the determination of how these serial values of PSA impact on prognosis. To understand HRPC fully, make decisions about choices of treatment as well as about clinical research on treatments for HRPC patients, and design appropriate measures of PSA response, it seems that first it would be necessary to understand how these serial measures of PSA relate to survival. The purpose of this study was to determine how repeated measurements of PSA impact on the probability of imminent death for patients with HRPC. METHODS: One hundred forty-eight men with HRPC were enrolled in Cancer and Leukemia Group B Study 9181, in which they were treated with either a low dose (160 mg/day) or a high dose (640 mg/day) of megestrol acetate (MA). Because preliminary data analysis indicated that these treatments had no effect on survival, the authors pooled the data to analyze the overall dynamics of PSA and survival during the follow-up period. The authors attempted to correlate initial and monthly PSA measurements, which were mandated by the study protocol, with the probability of death at any time during follow-up. For statistical analysis, the Cox proportional hazards model and the general linear model were used. In addition to the level of PSA, the authors used the relative velocity of PSA, which was defined as (dy/dt)/y, with "y" symbolizing serum PSA and "t" symbolizing time. RESULTS: Both log(PSA) and the average relative velocity of PSA (rva) were significantly correlated with survival time (P=0.0001 and P=0.0008, respectively), and the analysis performed with the Cox proportional hazards model yielded the following formula for a PSA hazard score: PSA hazard score =0.251*(log(PSA) - mean log(PSA)) + 24.5*(rva - mean rva) This hazard score tended to be higher for patients who were about to die. For example, there was a close correlation between the hazard score and the probability of death as the next observed event. Furthermore, the hazard score provided a dynamic measure of how PSA was affected by treatment. CONCLUSIONS: The average relative velocity of PSA has been identified by the authors as a new measure of the dynamics of PSA in HRPC. It can be determined from sequential values of PSA. This average, together with the log(PSA), are significantly related to the probability of imminent death.     

Hypermobility syndrome. When too much activity causes pain

Hypermobility of joints and spine is a consequence of abnormal laxity of ligaments, joint capsules and intervertebral discs. Hypermobility per se is a state, not a disease. However, it may lead to generalized arthralgia or localized symptoms (frequent ankle sprains, knee effusions, dislocations of the shoulders of recurrent episodes of back pain). These events may occur even after minor strains. Young women are preferentially affected. The term "hypermobility syndrome" is defined as a combination of hypermobility with arthralgia, low back pain, frequent dislocation or sprains. It is often the result of a hereditary disorder of connective tissue. Individuals with hypermobility are at increased risk for premature osteoarthrosis or polytopic disc degeneration of the spine. However, the vast majority of hyperlax individuals are free of symptoms. Those with symptoms who do not develop osteoarthrosis or disc degeneration usually experience spontaneous improvement with increasing age, thus losing their juvenile hyperlaxity. This usually occurs between the ages of thirty and forty. The present review article also provides guidelines for management and patient information.     

Oxygen scavenging polymer coating prepared by hydrophobic modification of glucose oxidase

Trace oxygen in packaged foods, beverages, and pharmaceuticals can promote a range of oxidative degradation reactions and support microbial growth, ultimately impacting product quality and shelf-life. Oxygen scavenging active packaging systems have therefore been explored to control headspace oxygen content. Herein, we report on a hydrophobic ion pairing method to render glucose oxidase hydrophobic, and thus soluble in organic solvents. Hydrophobic modified glucose oxidase was blended with ethylene vinyl acetate and cast on the interior of glass vials to demonstrate potential as a commercially translatable coating method for enzyme immobilization. The resulting oxygen scavenging polymer coatings were topographically uniform and presented 0.553 μg/cm² enzyme at the coating interface. The coatings effectively reduced headspace oxygen by 2% in a closed-vial system filled 50 vol% with citrate buffer, pH 3.5. Less than 25% protein migrated from the coating over an 8-week leaching study, with no detectable protein leached in the first 4 weeks. Hydrophobic ion pairing of glucose oxidase enabled a facile, high-throughput enzyme immobilization technique without use of complicated, time-consuming surface modification chemistries and reagents. Such oxygen scavenging polymer coatings can support controlling headspace oxygen in packaged goods, and thus retaining stability of oxygen-sensitive components such as colors, flavors, and nutrients.     

Analytical performance of an ultrasonic particle focusing flow cytometer

Creation of inexpensive small-flow cytometers is important for applications ranging from disease diagnosis in resource-poor areas to use in distributed sensor networks. In conventional-flow cytometers, hydrodynamics focus particles to the center of a flow stream for analysis, which requires sheath fluid that increases consumable use and waste while dramatically reducing instrument portability. Here we have evaluated, using quantitative measurements of fluorescent microspheres and cells, the performance of a flow cytometer that uses acoustic energy to focus particles to the center of a flow stream. This evaluation demonstrated measurement precision for fluorescence and side scatter CVs for alignment microspheres of 2.54% and 7.7%, respectively. Particles bearing 7 x 10(3) fluorophores were well resolved in a background of 50 nM free fluorophore. The lower limit of detection was determined to be about 650 fluorescein molecules. Analysis of Chinese hamster cells on the system demonstrated that acoustic focusing had no effect on cellular viability. These results indicate that the ultrasonic flow cytometer has the necessary performance for most flow cytometry applications. Furthermore, through robust engineering approaches and the combination of acoustic focusing with low-cost light sources, detectors, and data acquisition systems, it will be possible to achieve a low-cost, truly portable flow cytometer.     

Emergency nurses'' perceptions of critical incidents and stress debriefing

The efficacy of examining antinuclear antibody (ANA) was investigated as a screening test detecting subclinical immune disorders in infertility and sterility. ANA was measured in 116 unexplained infertile or sterile patients. The ANA positive rate was 43.5% in group A (habitual abortion, n = 23), 38.1% in group B (consecutive miscarriages, n = 21), 30.0% in group C (one miscarriage, n = 10), 16.7% in group D (one or more deliveries n = 12) 22.0% in group E (primary sterility, n = 50), and 22.4% in the control group (n = 54). The positive rate for all the infertile patients (group A+B) was 40.9% and significantly higher than that in for the control group (p < 0.05). Ten patients with positive ANA had 12 deliveries and 20 patients with negative ANA had 23 deliveries. The frequency of preeclampsia in the patients with positive ANA was higher than in those with negative ANA (41.7% versus 4.3%, p < 0.05). A higher incidence of premature deliveries was recognized in the patients with positive ANA than in those with negative ANA (41.7% versus 8.7%, p < 0.1). Average birth weight (> 35 week) for patients with and without positive ANA was 2,976g (n = 8) and 3,122g (n = 19) respectively. The former tends to be smaller than the latter (p < 0.1).     

Gastrointestinal tract symptoms and self-reported abuse: a population-based study

BACKGROUND/AIMS: A link between abuse and irritable bowel syndrome (IBS) has been reported in outpatients but remains controversial. No population-based studies have investigated this issue. The aim of this study was to determine the prevalence of abuse and its association with symptoms in a representative community sample. METHODS: An age- and sex-stratified random sample of residents of Olmsted County, Minnesota ranging in age from 30 to 49 years was mailed a valid self-report symptom questionnaire. Abuse was assessed by standard published criteria. RESULTS: Of the 919 responders (74%), the age-adjusted prevalence of any abuse was 41% in women and 11% in men, resulting in an age- and sex-adjusted prevalence of 26%. Symptoms of IBS, dyspepsia, and frequent heartburn were reported by 14%, 23%, and 12%, respectively. There was a significant association between IBS and sexual abuse, emotional or verbal abuse, and abuse in childhood and adulthood. Similarly, dyspepsia and heartburn were both significantly associated with abuse. In the population, 31% had visited a physician for gastrointestinal symptoms; the odds of visiting a physician were highest in those reporting abuse in adulthood and childhood. CONCLUSIONS: Self-reported abuse is common in middle-aged subjects; those who report abuse are more likely to have symptoms consistent with IBS, dyspepsia, or heartburn and to visit a physician for bowel symptoms.     

Absorption of isomeric, palmitic acid-containing triacylglycerols resembling human milk fat in the adult rat

The effect of the positional distribution of palmitic acid (16:0) in triacylglycerols (TAG) on 16:0 apparent absorption in adult rats was investigated. The rats were fed two diets which contained 30 energy % as fat with identical total fatty acid compositions, both containing 30% 16:0. The Betapol diet contained TAG with 73% of total 16:0 in the sn-2 position, the control diet contained TAG with 6% of total 16:0 in the sn-2 position. After six weeks on these diets, the rats were killed two or six hours after the last meal, and the small intestine was removed, cut into 10-cm segments, and the fatty acid composition of the segment's contents was determined. At both time points the amount of 16:0 in the intestinal segments starting at 40 cm from the stomach was much lower in the animals fed Betapol than in the animals fed the control diet. Overall absorption of 16:0 and stearic acid was significantly greater in the Betapol group. Absorption of oleic and linoleic acid from the small intestine was similar in both groups, although the overall absorption was significantly greater in the animals fed Betapol. Total fat absorption was significantly higher in the Betapol-fed rats than in the control-fed rats. No effect on calcium and nitrogen absorption, on plasma total cholesterol and TAG levels, and on bodyweights (growth) was seen. The data demonstrate that the positional distribution of the fatty acids in the TAG molecule affects the site of absorption in the small intestine and particularly the net absorption of saturated fatty acids.