This
study presents a method for modifying pectin with phenolic
acids catalyzed by lipase in a two-phase system of water/tetrahydrofuran.
Salicylic acid (SA) and its isomers, including m-hydroxybenzoic
acid (MHBA) and p-hydroxybenzoic acid (PHBA), were
grafted onto pectin, and the products were characterized via UV–vis,
Fourier transform infrared spectroscopy (FTIR), and 1H
NMR analyses to explore the reaction process and mechanism between
pectin and the three phenolic acids. Results indicated that lipase
played a dual role in the reaction, namely, catalyzing the hydrolysis
of the methyl group in the aqueous phase and esterifying the carboxyl
group of pectin with the phenolic hydroxyl group of the phenolic acids
in tetrahydrofuran. The grafting ratio of SA-modified pectin, MHBA-modified
pectin, and PHBA-modified pectin was 1.89, 10.58, and 20.32%, respectively,
and it was affected by the position of phenolic hydroxyl. Moreover,
the effects of phenolic acids on the emulsifying properties, antioxidant
activities, and antibacterial activities of the native and modified
pectins were evaluated. In several aspects, the emulsifying properties
of the modified pectins were better than those of native pectin. Moreover,
the grafting of phenolic acids only slightly affected the 1,1-diphenyl-2-picryl
hydrazine (DPPH) clearance of the modified pectins but substantially
improved their inhibition ratio in a β-carotene bleaching assay.
Furthermore, the modified pectins exhibited better bacteriostatic
activity against both Escherichia coli and Staphylococcus aureus than native
pectin.
Background
Uterine torsion is a rare obstetric event that can occur during pregnancy and is difficult to diagnose. Its occurrence may lead to serious adverse pregnancy outcomes.
Case introduction
The patient was a 33-year-old woman at 30+ 5 weeks’ gestation with a singleton pregnancy. The pregnancy course, including fetal growth, and prenatal examinations were regular. Except for a small amount of vaginal bleeding in early pregnancy and treatment with progesterone, there were no prenatal abnormalities, and the patient denied any trauma or sexual history. The patient was admitted to the emergency department with persistent severe pain in the lower abdomen and slight vaginal bleeding during night sleep. Abdominal pain started two hours prior to admission and was accompanied by nausea, vomiting, and dizziness. Examination revealed positive abdominal tenderness, high uterine tone, and no significant intermittent period of uterine contractions, and measurement of the fetal heart rate by means of the nonstress test revealed a rate of 60 beats per minute. Therefore, placental abruption was highly suspected. Subsequently, an emergency cesarean section was performed under general anesthesia. The newborn boy, with Apgar scores of 0–3-4 after birth and weighing 1880 g, was transferred to the neonatal intensive care unit (NICU) and died two days later due to ineffective rescue. After the uterine incision was sutured, the examination revealed that the uterine incision was located on the posterior wall of the uterus, and the uterus was twisted 180° to the right. The diagnosis after cesarean section was 180° uterine torsion to the right, severe placental abruption, and severe neonatal asphyxia. On the fifth day after surgery, the patient recovered and was discharged from the hospital.
Conclusions
Posterior uterine incision cesarean section may be performed in unexpected circumstances and is also feasible as a safe option for resetting if torsion is not complete. Abdominal pain during pregnancy is less likely to be diagnosed as uterine torsion, which often leads to premature birth, fetal asphyxia, placental abruption, and even perinatal death. Therefore, for abdominal pain during pregnancy, obstetricians should consider the possibility of uterine torsion.
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