47 research outputs found

    Looking beyond endotoxin: a comparative study of pyrogen retention by ultrafilters used for the preparation of sterile dialyis fluid

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    Sterile single-use ultrafilters are used in dialysis for the preparation of the substitution fluid given to patients undergoing dialysis treatments with high convective fluid removal. The retention of pyrogenic agents by the ultrafilters is crucial to avoiding inflammatory responses. The performance of a new single-use ultrafilter (NUF) with a positively charged flat sheet membrane of relatively small membrane area and large pore size was compared to a reference ultrafilter (RUF) with a hollow fiber membrane. Filter performance was tested with various pyrogen-contaminated dialysis fluids by direct pyrogen quantification and by measuring inflammatory responses in cell-based bioassays. The NUF completely retained oligodeoxynucleotides (ODN), whereas the RUF was fully permeable. Both filters tended to decrease biological activity of DNA in filtered bacterial lysates. The NUF reduced lipopolysaccharides (LPS) and LPS-induced biological activity by 100%, whereas the RUF produced filtrates with low but detectable levels of LPS in most cases. Peptidoglycans (PGN) were fully retained both by the NUF and the RUF. The new ultrafilter retained biologically active ODN, which has not yet been described for any other device used in dialysis, and it showed better or equal retention of LPS and PGN even with a smaller membrane surface and larger pore size

    The Dialyzer as the Last Line of Protection against Endotoxins

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    When dialysis fluid is contaminated with endotoxins, the dialyzer membrane is often referred to as the last line of protection to prevent endotoxins from entering the patient’s blood. However, a quantifiable requirement for this endotoxin retention property of the membrane has not yet been defined. The ANSI/AAMI/ISO 23500 standard series provides the framework for the microbiological quality of dialysis water, concentrates, and dialysis fluid, and defines the limit value for the non-pyrogenic endotoxin dose. After defining the boundary conditions of the endotoxin loading of the membrane by dialysis fluid and the patient’s non-pyrogenic endotoxin dose, quantifiable requirements for the endotoxin retention properties of a membrane, expressed as a dimensionless logarithmic retention value (LRV), were developed in this work. Based on standard dialysis fluid quality, the LRV should minimally be two for a protein-coated membrane after contact with patient blood and minimally be one for a protein-free pristine membrane during online priming before contact with patient blood. This work also presents the critical factors for endotoxin retention tests and shows that the defined LRV values are reached by membranes in modern dialyzers

    Likelihood of repeat abortion in a Swedish cohort according to the choice of post-abortion contraception: a longitudinal study

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    IntroductionDespite high access to contraceptive services, 42% of the women who seek an abortion in Sweden have a history of previous abortion(s). The reasons for this high repeat abortion rate remain obscure. The objective of this study was to study the choice of contraceptive method after abortion and related odds of repeat abortions within 3-4 years. Material and methodsThis is a retrospective cohort study based on a medical record review at three hospitals in Sweden. We included 987 women who had an abortion during 2009. We reviewed medical records from the date of the index abortion until the end of 2012 to establish the choice of contraception following the index abortion and the occurrence of repeat abortions. We calculated odds ratios (OR) with 95% CI. ResultsWhile 46% of the women chose oral contraceptives, 34% chose long-acting reversible contraceptives (LARC). LARC was chosen more commonly by women with a previous pregnancy, childbirth and/or abortion. During the follow-up period, 24% of the study population requested one or more repeat abortion(s). Choosing LARC at the time of the index abortion was associated with fewer repeat abortions compared with choosing oral contraceptives (13% vs. 26%, OR 0.36; 95% CI 0.24-0.52). Subdermal implant was as effective as intrauterine device in preventing repeat abortions beyond 3 years. ConclusionsChoosing LARC was associated with fewer repeat abortions over more than 3 years of follow up.Funding Agencies|Futurum - the academy for healthcare; Jonkoping County Council; Medical Research Council of Southeast Sweden (FORSS)</p

    Improved humid air condensation heat transfer through promoting condensate drainage on vertically stripe patterned bi-philic surfaces

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    Even when dropwise condensation occurs on the super-hydrophobic surface, the condensed water droplets stick to the surface in the Wenzel state, resulting in lower drainage rate than the super-hydrophilic surface. Condensate that is not drained consequently degrades condensation heat transfer performance over time. In this study, it was considered that the striped patterned bi-philic surface could improve the condensation heat transfer in that droplet of the near super-hydrophobic area can be quickly removed and drained to a nearby super-hydrophilic region. Rapid drainage of condensate from the near super-hydrophobic surface can result in the renewal of new dropwise condensation, which can lead to increased heat transfer. Condensate discharges from bi-philic surfaces fabricated by material printing were measured and compared to condensate discharges from fully super-hydrophilic and near super-hydrophobic surfaces. As decreasing the stripe width of the bi-philic surface, the drainage rate is improved due to the rapid growth of the droplet nucleate on the near super-hydrophobic surface and the increment of the drainage path. The maximum condensate discharge from the bi-philic surface was measured to be 15% higher than that of the entirely super-hydrophilic surface. The amount of condensate recovery from the bi-philic surface was predicted through film and dropwise condensation combined modeling. Through this model, the amount of condensate recovered from the bi-philic surface was predicted within the 8% error range. Determination of the optimal stripe pattern to maximize the amount of condensate recovery can be made through developed modeling. The optimized stripe design of bi-philic surface resulted in a 25% increase in condensate discharge compared to the entirely super-hydrophilic surface. (C) 2020 Elsevier Ltd. All rights reserved
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