Zinc Ammonio-dodecaborates: Synthesis, Lewis Acid Strength, and Reactivity.

Two series of zinc salts, [EtZn][A] and Zn[A]2, with weakly coordinating anions [A]- as counterions have been prepared, and their activities as catalysts for hydrosilylation reactions of 1-hexene, benzophenone, and acetophenone have been investigated. The counterions and per- and partially chlorinated 1-ammonio-closo-dodecaborate anions [Me3NB12Cl11]- [1]-, [Pr3NB12H5Cl6]- [2]-, [Bu3NB12H4Cl7]- [3]-, and [Hex3NB12H5Cl6]- [4]- were chosen as potential and more readily available alternatives to carborate anions such as [CHB11Cl11]- and [HexCB11Cl11]-. The basicity of anion [4]- was determined as being close to that of the triflimide anion [N(SO2CF3)2]-, and the fluoride ion affinities (FIAs) of compounds [EtZn][2] and Zn[2]2 are lower than those of the Lewis acids B(C6F5)3 and Zn[HexCB11Cl11]2. The higher anion basicity and the resulting lower Lewis acidity of the zinc centers result in low activity in 1-hexene hydrosilylation catalysis and only moderate activity in the hydrosilylation catalysis of benzophenone and acetophenone.

Quality of Labor Analgesia with Dural Puncture Epidural versus Standard Epidural Technique in Obese Parturients: A Double-blind Randomized Controlled Study.

BACKGROUND: The dural puncture epidural technique may improve analgesia quality by confirming midline placement and increasing intrathecal translocation of epidural medications. This would be advantageous in obese parturients with increased risk of block failure. This study hypothesizes that quality of labor analgesia will be improved with dural puncture epidural compared to standard epidural technique in obese parturients. METHODS: Term parturients with body mass index greater than or equal to 35 kg · m-2, cervical dilation of 2 to 7 cm, and pain score of greater than 4 (where 0 indicates no pain and 10 indicates the worst pain imaginable) were randomized to dural puncture epidural (using 25-gauge Whitacre needle) or standard epidural techniques. Analgesia was initiated with 15 ml of 0.1% ropivacaine with 2 µg · ml-1 fentanyl, followed by programed intermittent boluses (6 ml every 45 min), with patient-controlled epidural analgesia. Parturients were blinded to group allocation. The data were collected by blinded investigators every 3 min for 30 min and then every 2 h until delivery. The primary outcome was a composite of (1) asymmetrical block, (2) epidural top-ups, (3) catheter adjustments, (4) catheter replacement, and (5) failed conversion to regional anesthesia for cesarean delivery. Secondary outcomes included time to a pain score of 1 or less, sensory levels at 30 min, motor block, maximum pain score, patient-controlled epidural analgesia use, epidural medication consumption, duration of second stage of labor, delivery mode, fetal heart tones changes, Apgar scores, maternal adverse events, and satisfaction with analgesia. RESULTS: Of 141 parturients randomized, 66 per group were included in the analysis. There were no statistically or clinically significant differences between the dural puncture epidural and standard epidural groups in the primary composite outcome (34 of 66, 52% vs. 32 of 66, 49%; odds ratio, 1.1 [0.5 to 2.4]; P = 0.766), its individual components, or any of the secondary outcomes. CONCLUSIONS: A lack of differences in quality of labor analgesia between the two techniques in this study does not support routine use of the dural puncture epidural technique in obese parturients.

Analgesia After Cesarean Delivery in the United States 2008-2018: A Retrospective Cohort Study.

BACKGROUND: Optimizing analgesia after cesarean delivery is a priority and requires balancing adequate pain relief with the risk of analgesics-associated adverse effects. Current recommendations are for use of a multimodal, opioid-sparing analgesic regimen that includes neuraxial morphine combined with scheduled nonsteroidal anti-inflammatory drugs (NSAIDs) and scheduled acetaminophen. Furthermore, recent studies recommend scheduled acetaminophen with as-needed opioids in lieu of acetaminophen-opioid combination drugs to reduce opioid consumption and optimize analgesia. However, the extent of utilization of this recommended regimen in the United States is unclear. We therefore performed this retrospective study to evaluate postoperative analgesic regimens utilized after cesarean delivery under neuraxial anesthesia, examine variability across institutions, evaluate changes over time in postoperative analgesic practice, and examine factors associated with the use of neuraxial morphine and of multimodal analgesia. METHODS: This retrospective cohort study was approved by the Duke University Institutional Review Board. Parturients who underwent cesarean delivery under neuraxial anesthesia from 2008 to 2018 were included. Data were extracted from a nationwide inpatient administrative-financial database (Premier Inc, Charlotte, NC) and included parturient characteristics, comorbidities, hospital characteristics, and charges for administered medications. The primary outcome was the postoperative analgesic regimen utilized during hospitalization, including utilization of neuraxial morphine and of multimodal analgesia for postoperative pain control. We also examined the factors associated with the use of neuraxial morphine and of the multimodal regimen incorporating neuraxial morphine, NSAIDs, and acetaminophen. RESULTS: Data from 804,752 parturients were analyzed. Of this cohort, 75.8% received neuraxial morphine, 93.2% received NSAIDs, 28.4% received acetaminophen, and 81.3% received acetaminophen-opioid combination drugs. Only 6.1% received the currently recommended regimen of neuraxial morphine with NSAIDs and acetaminophen, with this percentage increasing from 1.3% in 2008 to 15.0% in 2018. On the other hand, 58.9% received neuraxial morphine, NSAIDs, and an acetaminophen-opioid combination drug, with this regimen being utilized in 57.0% of cases in 2008 and 58.1% in 2018. The hospital in which the patient was treated accounted for 54.7% of the variation in receipt of neuraxial morphine and 41.2% in the variation in receipt of multimodal analgesia with neuraxial morphine, NSAIDs, and acetaminophen, with this variability in receipt of neuraxial morphine and of multimodal analgesia being largely independent of patient characteristics. CONCLUSIONS: Relatively few parturients received the currently recommended multimodal analgesic regimen of neuraxial morphine with NSAIDs and acetaminophen after cesarean delivery. Additionally, the majority received acetaminophen-opioid combination drugs rather than plain acetaminophen. Further studies should investigate the implications for patient outcomes.

Missense Mutations Allow a Sequence-Blind Mutant of SpoIIIE to Successfully Translocate Chromosomes during Sporulation.

SpoIIIE directionally pumps DNA across membranes during Bacillus subtilis sporulation and vegetative growth. The sequence-reading domain (γ domain) is required for directional DNA transport, and its deletion severely impairs sporulation. We selected suppressors of the spoIIIEΔγ sporulation defect. Unexpectedly, many suppressors were intragenic missense mutants, and some restore sporulation to near-wild-type levels. The mutant proteins are likely not more abundant, faster at translocating DNA, or sequence-sensitive, and rescue does not involve the SpoIIIE homolog SftA. Some mutants behave differently when co-expressed with spoIIIEΔγ, consistent with the idea that some, but not all, variants may form mixed oligomers. In full-length spoIIIE, these mutations do not affect sporulation, and yet the corresponding residues are rarely found in other SpoIIIE/FtsK family members. The suppressors do not rescue chromosome translocation defects during vegetative growth, indicating that the role of the γ domain cannot be fully replaced by these mutations. We present two models consistent with our findings: that the suppressors commit to transport in one arbitrarily-determined direction or delay spore development. It is surprising that missense mutations somehow rescue loss of an entire domain with a complex function, and this raises new questions about the mechanism by which SpoIIIE pumps DNA and the roles SpoIIIE plays in vivo.