Factors associated with postpartum follow-up and persistent hypertension among women with severe preeclampsia.

OBJECTIVE: To determine factors associated with lower 6-week postpartum follow-up rates and persistent hypertension among women with preeclampsia with severe features (PEC-S). STUDY DESIGN: Planned secondary analysis of a retrospective cohort study of women with PEC-S. Outcomes were (1) attendance at the 6-week postpartum visit and (2) persistent hypertension. RESULTS: One hundred ninety-three women were in the final cohort. The 6-week follow-up rate was 52.3%. Factors associated with lower follow-up were African-American race (OR 0.37 (0.18-0.77)) and <5 prenatal visits (OR 0.44 (0.20-0.97)). Women with diabetes and women with a cesarean had higher follow-up (OR 4.00 (1.09-14.66) and 2.61 (1.40-4.88), respectively). Among those with 6-week follow-up, 21% had persistent hypertension. Obese women, women diagnosed with PEC-S by severe range blood pressure (BP) and women discharged home on BP medication were more likely to have persistent hypertension (OR 3.50 7 (1.06-11.58), 3.58 (1.11-11.54) and 3.04 (1.12-8.23), respectively). CONCLUSION: We identified a subgroup of women at higher risk for poor postpartum follow-up and those at risk for persistent hypertension.

Induction, labor length and mode of delivery: the impact on preeclampsia-related adverse maternal outcomes.

OBJECTIVE: The objectives were to evaluate whether induction, specifically prolonged labor, was associated with adverse maternal outcomes related to preeclampsia with severe features (PEC-S) and whether cesarean affected the rate. STUDY DESIGN: This was a retrospective cohort study of women with PEC-S ⩾34 weeks who were diagnosed either before planned cesarean or before induction/latent labor. The primary outcome was a composite adverse maternal outcome related to PEC-S. RESULTS: The final cohort comprised 193 women (n=172 with labor and n=21 with planned cesarean). The prevalence of the outcome was 15.5%. Women exposed to labor did not have a higher rate compared with planned cesarean (16.3% vs 9.5%, P=0.4). Adjusting for confounders, women with a cesarean after prolonged labor had a 10-fold higher adverse outcome risk compared with women with a planned cesarean (adjusted odds ratio (aOR) 9.7 (1.2 to 78.6), P=0.03) or with a vaginal delivery <24 h (aOR 9.7 (1.4 to 67.4), P=0.02). CONCLUSION: Prolonged labor and cesarean in labor were both associated with an increase in our outcome.

Plasma preparation from whole blood using ultrasound.

A technique to efficiently separate plasma from human whole blood is described. Essentially, 3-mL samples are held on the axis of a tubular transducer and exposed for 5.7 min to an ultrasonic standing wave. The cells concentrate into clumps at radial separations of half wavelength. The clumps grow in size and sediment under gravity. A distinct plasma/cell interface forms as the cells sediment. The volume of clarified plasma increases with time. The separation efficiencies of transducers of 29-mm and 23-mm internal diameters driven, by test equipment, at radial resonances of 3.4 and 1.5 MHz, respectively, were compared. The average efficiency of separation was 99.6% at 1.5 MHz and 99.4% with the 3.4-MHz system. The cleared plasma constituted 30% of the sample volume at 1.5 MHz and 25% at 3. 4 MHz. There was no measurable release of haemoglobin or potassium into the suspending phase, indicating that there was no mechanical damage to cells at either frequency. A total of 114 samples from volunteers and patients were subsequently clarified in a 1.5-MHz system driven by an integrated generator. The average efficiency of clarification of blood was 99.76% for the latter samples. The clarification achieved is a significant improvement on that previously reported (98.5%) for whole blood exposed to a planar ultrasonic standing wave field (Peterson et al. 1986). We have, therefore, now achieved a six-fold reduction of cells in plasma compared to previous results.

Clarification of small volume microbial suspensions in an ultrasonic standing wave.

The removal of Saccharomyces cerevisiae and Escherichia coli from 2.5 ml suspensions in ultrasonic standing wave formed at 1 or 3 MHz has been characterized. The standing wave was set up by a plane transducer and reflector mounted in the vertical plane. Cells in the ultrasonic field first concentrated in vertical planes at half wavelength separations. The ultrasound was then pulsed to allow clumps of concentrated cells to sediment in a controlled way during the short 'off' intervals. Yeast removal from suspension at a concentration of 3 x 10(9) ml-1 (14% volume v/v) was 99.5% in a total time of 4.5 min. Almost total (99.5%) clarification of prokaryote (E. coli) suspension was achieved here for the first time in a standing wave field. The clarification of a 1.3 x 10(11) ml-1 (16% v/v) E. coli suspension occurred over 11.5 min. The period decreased to 7 min in the presence of a polycationic flocculant, polyethyleneimine. The implications of the results for design of systems to further reduce clarification times are discussed. Removal efficiency for both S. cerevisiae and E. coli decreased with decrease in cell concentration. This concentration dependence is shown not to be simply a consequence of acoustic interaction between single cells. Flow cytometry of stained cells detected no loss of cell viability arising from the ultrasonic procedure.

Filtration of bacteria and yeast by ultrasound-enhanced sedimentation.

Continuous flow filtration of suspensions of eukaryotic cells by ultrasonic standing wave enhanced sedimentation has recently been reported. The filtration efficiency for Escherichia coli in such a filter has been characterized at frequencies of 1 and 3 MHz in the present work and compared with results for Saccharomyces cerevisiae. The yeast can be filtered at greater than 99% efficiency at a flow rate of 5 ml min-1 at either frequency. The filtration efficiency of the smaller E. coli at 3 MHz is in excess of 80% at concentrations in the region of 10(10) ml-1 but decreased at lower concentrations. However, E. coli in a mixed suspension with yeast were, because of inter-particle interactions, removed with the filtrate at an efficiency ranging from 80 to 50% over the eight orders of bacterial concentrations tested (down to 10(3) ml-1) at 3 MHz. Quantitative considerations show that poor filtration of pure suspensions of the smaller cells at the lower frequency arises because, at reasonable flow rates, the residence time is not sufficient for the cells to reach the pressure nodal cell concentration regions. The filtration efficiencies of both cell types are comparable at 3 MHz. It is suggested that the more comparable efficiencies arise because concentration regions are narrower at the high frequency and Stokes drag by the filter bulk flow inhibits sedimentation of the concentrated cells.

In vitro drug resistance in acute myeloid and chronic B-lymphocytic leukaemic blasts and in normal blood and marrow populations.

The sensitivities of AML and BCLL blasts to daunorubicin have been determined, using an in vitro (MTT) assay of resistance, and compared with the sensitivities of normal haemopoietic populations and cells of the multidrug-resistant, T-lymphoid line CEM VLB100; The role of the drug-efflux pump, P-glycoprotein, was determined by adding the 'modifier' cyclosporin and by measuring numbers of P-glycoprotein positive cells by immunofluorescence. ID50s for 17 cases of de novo AML varied from 5 to 300 ng/ml giving a median of 105 ng/ml which was similar to the median of 11 normal marrow mononuclear cell preparations (80 ng/ml) but considerably less than the median ID50 of eight blood lymphocyte samples (3500 ng/ml). ID50s for five relapsed and two refractory AML samples ranged from 27 to 240 ng/ml, well within the de novo range: we had obtained presentation samples for two of these and, in both cases, ID50s were lower at relapse. ID50s, however, were raised in seven marrow mononuclear cell populations taken soon after remission induction (ID50 for remission MNC and normal MNC = 200 and 80 ng/ml, respectively); this may reflect either a property of regenerating populations, or an activation of cellular resistance mechanisms following chemotherapy. ID50s for 17 cases of BCLL ranged from 7 to 200 ng/ml with a median of 48 ng/ml which was significantly lower than the ID50 of AML blasts or of blood lymphocytes. Cyclosporin induced less than two-fold reductions in ID50s of blood lymphocytes, marrow mononuclear cells and de novo AML and BCLL blasts despite giving log reversals in resistance in the CEM VLB100 line. This reflected numbers of P-glycoprotein positive cells in our samples, which were high in CEM VLB100 but low in fresh normal or leukaemic cell suspensions. For both de novo AML and BCLL groups, however, the change in ID50, on addition of cyclosporin, was significant. These data imply a minor role for P-glycoprotein in drug resistance of leukaemic blasts. Nevertheless, there was a positive correlation between daunorubicin ID50s in de novo AML and time to remission which confirms that in vitro chemosensitivity assays can provide a useful measure of in vivo resistance.

Influence of fluoride containing toothpaste on serum and urine fluoride levels in children.

This study was undertaken to investigate the effect of fluoridated toothpaste on serum and urine fluoride levels in two groups of children with supervised brushing. As part of the study dietary intakes of fluoride were calculated from a 24 hour diet record and eight samples of water from different families were also analysed for their fluoride content.

A clinical evaluation of glove washing and re-use in dental practice.

This study has assessed the durability of four brands of latex gloves, Ansell Medical 'Medi-Grip', Regent 'Biogel D', Surgikos 'Microtouch' and the London Rubber Company 'Supreme', under conditions of repeated washing and re-use in a clinical dental setting. The microbiological effectiveness of 'Hibiscrub' as a decontaminating washing agent was examined simultaneously. Examination by an electrical test for micropunctures in 200 unused gloves of each brand revealed such defects in 6(3%) of Ansell 'Medi-Grip', 3(1.5%) of 'Biogel D', 14(7%) of Surgikos 'Microtouch' and 2(1%) of LRC 'Supreme' gloves. Following repeated clinical use, micropunctures were detected in 18% of Ansell 'Medi-Grip', 10% of 'Biogel D', 75% of Surgikos 'Microtouch' and 56% of LRC 'Supreme'. Microorganisms were isolated from the glove surfaces after 45% of the occasions on which the gloves were washed for 1 min in 'Hibiscrub' (ICI Dental). Eighty-five per cent of these isolates were environmental organisms, but oral streptococci were isolated from 8.4% of the pairs of gloves examined. The high rate of micropuncture development following repeated washing and re-use of latex gloves indicates that they cannot effectively perform their barrier function under such conditions. The microbiological data have also revealed the potential for cross-infection between patients through inadequate decontamination of glove surfaces. For operative dental surgery, the results suggest that heavier, surgical type gloves are to be preferred, and that multiple use of any glove type should be discouraged.