Objective:To evaluate the clinical efficacy of extensively hydrolyzed protein formula(eHF) in very low birth weight(VLBW) infants.Methods:A prospective controlled signal-center trial was conducted in this study, the preterm infants with gestational age of 28-33 weeks and birth weight of 999-1 500 g who were hospitalized at Department of Neonatology, Zhuhai Maternal Hospital within the first 12 hours between January and December 2018, were selected.They were assigned into breast feeding group(HM) and formula feeding group according to the mothers′ disease and parents′ breastfeeding willingness.The formula feeding group was assigned into eHF group and preterm formula (PF)group according to the parents′ breastfeeding willingness.The infants discharging or dead before achieving full feeding, discharging within 28 days after birth, with congenital malformation (complex congenital heart disease, digestive system malformation, etc) and severe sepsis were rolled out. Chi- square test and One- Way ANOVA were used for statistical analysis.Prospective study was conducted among the 3 groups comparing the incidence of feeding intolerance, duration of meconium discharge, the time to regain birth weight and reach full enteral feeding, average hospital stay, incidence of necrotizing enterocolitis of newborn(NEC), cholestasis and extrauterine growth retardation(EUGR), the growth rate of head circumference, length and weight in the first 4 weeks of life, and blood biochemical indices at the first 2 weeks and 4 weeks of life. Results:A total of 102 infants were enrolled, 35 cases in the eHF group, 37 cases in the PF group and 30 cases in the HM group.Compared with the PF group [54.0%(20/37 cases)], the eHF group[22.0%(8/35 cases)] and the HM group [16.7%(5/30 cases)] had lower incidence of feeding intolerance, and the differences were statistically significant( χ2=7.366, 9.901, all P<0.05). The time to regain birth weight[(8.9±1.8) d, (9.1±1.4) d vs.(10.8±2.9) d], time for achieving full enteral feeding [(42.8±2.8) d, (42.3±3.3) vs.(45.5±3.4) d], the duration of meconium discharge [(7.2±1.8) d, (6.6±1.8) d vs.(8.7±2.1) d], and average hospital stay [(52.9±1.1) d, (52.3±1.2) d vs.(54.1±1.2) d]in the eHF group and HM group were shorter than those in PF group, and the differences were statistically significant(all P<0.05); and there was no statistically significant difference between the eHF group and the HM group(all P>0.05). There was no statistically significant difference in the incidence of incidence of NEC, cholestasis and EUGR, the growth rate of head circumfe-rence, length and weight in the first 4 weeks of life, the serum albumin, creatinine, urea nitrogen at first 2 weeks and 4 weeks of life among the 3 groups (all P>0.05). Compared with the PF group, the serum total bilirubin levels in the eHF group and the HM group were lower at 2 weeks [(109.4± 4.6) μmol/L, (110.2±1.0) μmol/L vs.(115.0±7.6) μmol/L]and 4 weeks after birth[(79.3±9.7) μmol/L, (80.0±1.7) μmol/L vs.(81.5±8.4)μmol/L], and the differences were statistically significant(all P<0.05), but no statistically significant difference was found between the eHF goup and the HM group(all P>0.05). Conclusions:For VLBW infants, eHF can reduce feeding intole-rance, promote defecation, achieve full feeding faster, promote bilirubin metabolism, shorten hospital stay, does not affect growth and development in short-term.

Kv2.1 channel currents in pancreatic beta-cells are thought to contribute to action potential repolarization and thereby modulate insulin secretion. Because of its central role in this important physiological process, Kv2.1 channel is a promising target for the treatment of type 2 diabetes. Jingzhaotoxin-XI (JZTX-XI) is a novel peptide neurotoxin isolated from the venom of the spider Chilobrachys jingzhao. Two-microelectrode voltage clamp experiments had showed that the toxin inhibited Kv2.1 potassium currents expressed in Xenopus Laevis oocytes. In order to investigate the structure-function relationship of JZTX-XI, the natural toxin and a mutant of JZTX-XI in which Arg3 was replaced by Ala, were synthesized by solid-phase chemistry method with Fmoc-protected amino acids on the PS3 automated peptide synthesizer. Reverse-phase high performance liquid chromatography (RP-HPLC) and matrix assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to monitor the oxidative refolding process of synthetic linear peptides to find the optimal renaturation conditions of these toxins. The experiments also proved that the relative molecular masses of refolded peptides were in accordance with their theoretical molecular masses. RP-HPLC chromatogram of co-injected native and refolded JZTX-XI was a single peak. Under the whole-cell patch-clamp mode, JZTX-XI could completely inhibit hKv2.1 and hNav1.5 channels currents expressed in HEK293T cells with IC50 values of 95.8 nmol/L and 437.1 nmol/L respectively. The mutant R3A-JZTX-XI could also inhibit hKv2.1 and hNav1.5 channel currents expressed in HEK293T cells with IC50 values of 1.22 micromol/L and 1.96 micromol/L respectively. However, the prohibitive levels of R3A-JZTX-XI on hKv2.1 and hNav1.5 channels were reduced by about 12.7 times and 4.5 times respectively, indicating that Arg3 was a key amino acid residue relative to the hKv2.1 channel activity of JZTX-XI, but it is also an amino acid residue correlated with the binding activity of JZTX-XI to hNav1.5 channel. Our findings should be helpful to develop JZTX-XI into a molecular probe and drug candidate targeting to Kv2.1 potassium channel in the pancreas.
Animals ; HEK293 Cells ; Humans ; Insulin-Secreting Cells ; metabolism ; Mutant Proteins ; genetics ; pharmacology ; NAV1.5 Voltage-Gated Sodium Channel ; metabolism ; Neurotoxins ; chemical synthesis ; genetics ; pharmacology ; Protein Refolding ; Shab Potassium Channels ; antagonists & inhibitors ; metabolism ; Sodium Channel Blockers ; pharmacology ; Spider Venoms ; genetics ; pharmacology ; Transfection

Objective: To identify the time window during which the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway plays a key role in telogen-to-anagen transition of hair follicles, and to explore whether the pathway specifically promotes the proliferation of hair follicle stem cells (HFSCs) . Methods: Totally, 36 newborn ICR mice were randomly and equally divided into 3 groups: RAPA-P19 group intraperitoneally injected with 5 mg·kg^-1·d^-1 sirolimus on days 19-24 after birth, RAPA-P21 group intraperitoneally injected with 5 mg·kg^-1·d^-1 sirolimus on days 21-24 after birth, and control group intraperitoneally injected with the same volume of solvent on days 19-24 after birth. Four mice were sacrificed in each group on days 22, 23 and 24 separately. Skin tissues were resected from the back, and hematoxylin-eosin staining of the skin tissues were performed followed by observation of hair follicle morphology to evaluate whether murine hair follicles progressed into the anagen phase on day 24. Immunofluorescence costaining was conducted to determine the expression and localization of mTORC1 downstream molecular marker pS6 and cell proliferation marker Ki67 on days 22 and 23. Results: On day 24, hematoxylin-eosin staining showed anagen hair follicles in the control group and RAPA-P21 group, but telogen hair follicles in the RAPA-P19 group. On days 22 and 23, immunofluorescence costaining revealed positive staining for both pS6 and Ki67 in HFSCs in the control group, negative staining for both pS6 and Ki67 in the RAPA-P19 group, negative staining for pS6 and positive staining for Ki67 in the RAPA-P21 group. On day 23, epidermal cells and sebaceous gland cells in the upper hair follicle bulge were stained positively for Ki67 in all the 3 groups. Conclusion mTORC1 signaling specifically promotes the proliferation of HFSCs during telogen-to-anagen transition, but not affects proliferation of other cells in hair follicles.