Platelet transfusion reactions were prospectively studied in haematology/oncology patients at five university teaching hospitals over three consecutive summers. The initial summer study provided baseline information on the use of premedications and the rate of platelet transfusion reactions (fever, chills, rigors and hives). Most (73%) platelet recipients were premedicated and 30% (95% CI 28-33%) of transfusions were complicated by reactions. The second study followed implementation of guidelines for premedicating platelet transfusions. Despite a marked reduction in premedication (50%), there was little change in the platelet transfusion reaction rate, 26% (95% CI 24-29%), or the type of reactions. The third study followed implementation of prestorage platelet leukoreduction while maintaining the premedication guidelines. The reaction rate decreased to 19% (95% CI 17-22%). For nonleukoreduced platelets, there was a statistically significant association between the platelet age and reaction rate (P = 0.04). For leukoreduced platelets, there was no statistically significant association between platelet age and reaction rate (P = 0.5). Plasma reduction of nonleukoreduced platelet products also reduced the reaction rate. These prospective studies document a high rate of platelet transfusion reactions in haematology/oncology patients and indicate premedication use can be reduced without increasing the reaction rate. Prestorage leukoreduction and/or plasma reduction of platelet products reduces but does not eliminate febrile nonhemolytic platelet transfusion reactions.
ObjectivesTo examine the patterns of fat mass gain in pregnancy and fat loss in the early postpartum period relative to women’s pre-pregnancy body mass index (BMI) and by adherence to Institute of Medicine’s gestational weight gain (GWG) recommendations.DesignProspective cohort study with three to four study visits.SettingThis study is a part of the prospective longitudinal birth cohort, ‘The Alberta Pregnancy Outcomes and Nutrition Study’ (APrON) that recruited pregnant women from the cities of Edmonton and Calgary in Alberta.Participants1820 pregnant women were recruited and followed through their pregnancy and at 3 months postpartum.Outcome measuresBody weight and skinfold thicknesses were measured during pregnancy and early postpartum in women. Body density was calculated from sum of skinfold thickness (biceps, triceps, subscapula and suprailiac), and total fat mass accretion during pregnancy was calculated using Van Raaij’s equations and at postpartum using Siri’s equation. Differences in total fat mass gain, fat mass loss and fat retention according to pre-pregnancy BMI categories and GWG categories were tested using two-way analysis of variance and post hoc comparisons.ResultsMost women (64%) had a normal pre-pregnancy BMI, and overall 49% women exceeded the GWG recommendations. Obese women gained significantly less total fat mass, had lower fat mass loss and had lower postpartum fat retention than normal-weight women (p<0.05). Women with excessive GWG gained higher total fat mass and had higher postpartum fat mass retention (p<0.03) than women who met the GWG recommendations. Total GWG was positively correlated with total fat gain (r=0.61, p<0.01) and total fat retention (r=0.31, p<0.05).ConclusionExcessive GWG is the significant risk factor for higher fat mass accretion during pregnancy and higher postpartum fat retention, irrespective of pre-pregnancy BMI.
The stability of a variety of linear and cyclic (BN)n (n = 1-3) adducts with N-heterocyclic carbene (ImMe2; ImMe2 = [(HCNMe)2C:]), N-heterocyclic olefin (ImMe2CH2) and Wittig (Me3PCH2) donors has been examined using M05-2X/cc-pVTZ computations. The strength and nature of the bonds have been investigated using natural bond orbital (NBO) and atoms-in-molecules (AIM) analyses. Complementary energy decomposition analysis (EDA-NOCV) has been carried out based on BP86/TZ2P computations. In agreement with NBO and AIM analyses, the orbital interaction energy obtained from EDA contributes at least 50% to the total attractive interactions for the carbon-boron bonds indicating their largely covalent nature. The feasibility of isolating monomeric (BN)n units using a donor/acceptor protocol was also investigated in a series of adducts of the general form: LB·(BN)n·BH3 and LB·(BN)n·W(CO)5 (n = 1-3; LB = Lewis bases). Moreover, EDA-NOCV analysis of ImMe2·BN·W(CO)5 and ImMe2·B3N3·W(CO)5 shows that the carbene-boron bonds are stronger in the presence of W(CO)5 as a Lewis acid mainly because of a dramatic decrease in the amount of Pauli repulsion rather than an increase in the electrostatic/orbital attraction terms.
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