Isolation and allergenicity evaluation of glycated α-lactalbumin digestive products and identification of allergenic peptides

This study aimed to isolate and evaluate the allergenicity of glycated α-lactalbumin (ALA) digestive products and identify its allergenic peptides. The digestive products of native-, alone glycated- and ultrasound-assisted glycated ALA (ALA-D, ALA-gal-D, 100ALA-gal-D) were isolated into three fractions (F1, F2 and F3). High-resolution mass spectrometry showed that the digestion-resistant peptides of F2 and F3 mainly distributed in amino acid sequence (AA) 25-31, AA32-53, AA40-53, AA54-60, AA80-90, AA94-104. The allergenicity of the three fractions of glycated ALA was lower than that in ALA-D, indicating glycation of ALA could indeed reduce its allergenicity after digestion. Furthermore, most fractions isolated from high glycation-degree ALA had the lowest allergenicity. The IgG/IgE binding abilities of synthesized peptides indicated that AA94-104 firstly identified by us embodied the strongest allergenicity and might be the potential allergenic peptide. This will provide a theory for preparing hypoallergenic products based on the identified allergenic peptides.

Flavor, antimicrobial activity and physical properties of gelatin film incorporated with of ginger essential oil

Adding essential oil into the gelatin-based film can enhance the antibacterial activity of the film, but excessive amounts of addition will bring the film an unpleasant flavor and reduce its mechanical performance. Hence, we prepared functional gelatin-based films by incorporating low content of ginger essential oil (GEO). The flavor of GEO was not detected from the films containing less than 1% GEO. The antimicrobial activity of films was found to be proportional to GEO content. As GEO content increased from 0 to 1%, the value of water vapor permeability (WVP) and elongation at break (EAB) increased, whereas the value of tensile strength (TS) of film decreased. The Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy analysis revealed the vibration of gelatin film was affected by adding low content of essential oil. Surface morphologies demonstrated oil droplets and a discontinuous structure, and cross-section morphologies proved the formation of a loose structure as GEO was incorporated in the film through SEM. Sensory evaluation revealed that composite films incorporated with 0.5% GEO exhibited the best performance. The resulting films can be used as antimicrobial packaging materials with good physical properties and sensory performance.

[Endovascular repair of ruptured abdominal aortic aneurysms assisted by double balloon occlusion technique combined with intra-aneurysm fibrin binder injection technique]

Objective: To investigate the long-term efficacy and safety of alternating double balloon occlusion combined with intra-aneurysm injection of human fibrin binder in the endovascular repair of ruptured abdominal aortic aneurysm (rAAA). Methods: The clinical data of 28 patients with rAAA admitted to Department of Vascular Surgery, the Fourth Affiliated Hospital of Guangxi Medical University from January 2015 to December 2019 were retrospectively analyzed. There were 23 males and 5 females, aged (62±5) years (range: 46 to 88 years).The maximum diameter of the tumors was (65.2±10.5) mm (range: 47.3 to 100.5 mm), all of which were subrenal rAAA. The intraoperative EVAR for abdominal aortic aneurysm was successfully performed under the emergency green channel procedure, and this surgery was assisted used the double balloon occlusion technique in aorta of inferior renal and superior renalcombined with intraoperative human fibrin binder injection technique. Observation indexes included: patients with preoperative preparation, operation time, hospitalization days, surgical treatment success rate and the incidence of postoperative complications, and aortic stent form during the follow-up period, the incidence of leakage, branch stents patency rate and infection rates. Results: The preoperative preparation time of 28 patients was (45.5±8.5) minutes (range:20 to 100 minutes). The operation time was (100.0±15.5) minutes (range:85 to 210 minutes), the ICU stay time was (7±2) days(range:1 to 17 days). The length of hospitalization was (13.5±2.5) days(range:5 to 43 days). The success rate of surgical treatment was 92.9% (26/28). Two patients died, 1 case died of postoperative multifocal lacunar cerebral infarction and massive gastrointestinal hemorrhage, and another elderly patient (84 years old) died of massive abdominal fluid due to preoperative abdominal aortic aneurysm rupture, postoperative complicated with significant abdominal compartment syndrome, and secondary multiple organ failure. Balloon occlusion of the upper renal aorta took (13±2)minutes (range:12 to 30 minutes). The intraoperative injection of fibrin adhesive was (14±2) ml(range:6 to 28 ml) in 22 cases. The incidence of major postoperative complications was 57.1% (16/28). Among the 26 patients who survived the surgery, 69.2% (18/26) completed the 3-year follow-up, and the follow-up time was (30±3) months(range:13 to 36 months). During the follow-up, the aortic stent was in good shape without obvious displacement. The incidence of leakage within 6 months after the operation was 10.7% (3/28), and there was no internal leakage in the patients who were followed up for 36 months after the operation. The patency rate of renal artery and iliac artery branch stents was 16/18. The incidence of stent infection was 7.7% (2/26), 1 case occurred at 1 month and another case at 6 months, respectively. All patients recovered after prolonged intensive anti-infection therapy. Conclusions: Under the standard emergency treatment process, the double balloon alternating occlusion technique combined with the intra-aneurysm injection of human fibrin adhesive technique can assist the successful completion of the endovascular repair of rAAA, effectively improve the success rate of treatment for patients, and reduce the incidence of postoperative leakage and serious complications. The mid-term and long-term results of EVAR for rAAA are good, safe and reliable.

Mechanism on the Allergenicity Changes of α-Lactalbumin Treated by Sonication-Assisted Glycation during In Vitro Gastroduodenal Digestion

Physical-assisted chemical modification is effective to reduce the allergenicity of α-lactalbumin (ALA). However, there are few in-depth studies on the allergenicity changes of physical-assisted chemical-modified ALA during digestion. The effect of gastroduodenal digestion on the allergenicity changes of ALA treated by sonication-assisted glycation was assessed. Digestion of both ALA and its glycated forms generated peptide fractions, and intact undigested glycated ALA in the hydrolysates still covalently bound to d-galactose. High-resolution mass spectrometry revealed that a higher glycation degree was discovered in sonication-preprocessed ALA compared to native ALA. Enzyme-linked immunosorbent assay and basophil degranulation showed that sonication-assisted glycation could significantly reduce ALA allergenicity. The allergenicity of both gastric and gastroduodenal hydrolysates was further increased, and the hydrolysates of sonication-assisted glycated ALA showed the lowest allergenicity. The reason could be the shielding effect of the linear epitope found to be caused by a higher glycation degree; although linear epitopes were exposed, d-galactose covalently bound to intact undigested glycated ALA in the hydrolysates retained its masking role. These results indicated that sonication-assisted glycation could be a promising method to prepare immunotherapeutic agents for allergen immunotherapy to achieve the purpose of allergy desensitization.

Mechanism of the Reduced IgG/IgE Binding Abilities of Glycated β-Lactoglobulin and Its Digests through High-Resolution Mass Spectrometry

Glycation between proteins and reducing sugars is the common chemical modification in food protein, and many studies have focused on the allergenicity of the glycated protein. However, a systemic study on the allergenicity change of its digests is lacking. In this work, we explored the change rule of the digestibility and allergenicity of glycated β-Lg during in vitro gastrointestinal digestion and interpreted the mechanism using high-resolution mass spectrometry. Glycation with arabinose increased the resistance of β-Lg to digestive enzyme, with a low hydrolysis value. Indirect competitive ELISA showed that the IgG/IgE binding rates of β-Lg were reduced after glycation and further reduced after digestion, in comparison with the digests of unglycated β-Lg. There are two reasons for this phenomenon. On the one hand, 11 glycated sites were determined in the lowest allergenicity arabinose-β-Lg conjugation (Ara-β-Lg), which was distributed in the IgG and IgE linear allergic epitopes of β-Lg. On the other hand, glycation masking linear allergenic epitopes had a more significant effect on reducing allergenicity in comparison to digestive enzyme hydrolysis. These results indicated that the allergenicity of Ara-β-Lg in the human body might be lower than that of unglycated β-Lg.

Effect and Mechanism of Elaeagnus angustifolia Flower and Its Major Flavonoid Tiliroside on Inhibiting Non-enzymatic Glycosylation

This study aimed to evaluate the antiglycation ability of Elaeagnus angustifolia flower extract and to elucidate the mechanism with its major compound. The results indicated that E. angustifolia flower extract and its major compound tiliroside (24.2 mg/g of extract) exhibited excellent antiglycation ability with inhibition rates of 92.1 and 78.9% at 37.5 μg/mL, which are much higher than that of aminoguanidine (55.3% at 37.5 μg/mL). The stable tiliroside-ovalbumin (OVA) complexes were formed through a spontaneous exothermic progress in an equimolar manner, and hydrophobic interaction, hydrogen bond, and van der Waals forces were the major driving forces. Tiliroside could significantly ameliorate the conformation changes of OVA induced by the glycation reaction, quench its fluorescence by a static mechanism, and change the microenvironment adjacent to tryptophan and tyrosine. Molecular docking revealed that tiliroside inserted into the OVA hydrophobic pocket resulted in the formation of five hydrogen bonds. Orbitrap tandem mass spectrometry showed that tiliroside significantly suppressed the glycation of OVA, and the number of glycation sites was reduced from 9 to 5 after tiliroside was added. The above results indicated that E. angustifolia flowers and tiliroside have a good antiglycation effect and can be used as food additives to suppress the undesired glycation reaction during food processing.

Effects of γ-polyglutamic acid on the gelling properties and non-covalent interactions of fish gelatin

The effects of γ-polyglutamic aid (γ-PGA) on the gelling properties and non-covalent interactions of fish gelatin were investigated. The gel strength and melting temperature of fish gelatin gradually increased, with increasing γ-PGA concentration, although there was no significant change when the γ-PGA concentration was greater than 0.04%. As the concentration of γ-PGA increased, the electrostatic interaction of fish gelatin increased and the hydrophobic interaction between gelatin molecules decreased. The fish gelatin system was comprised of γ-PGA concentrations of 0.04 and 0.06% showing a strong hydrogen bond. When the γ-PGA concentration increased from 0 to 0.04%, more phenolic hydroxyl groups in the tyrosine residue tended to form hydrogen bonds with the protein. However, an additional increase in γ-PGA concentration to 0.1% led to enhanced hydrogen bonding with water molecules. The results of this study showed that hydrogen bonds played an important role in improving the gelling properties of gelatin by γ-PGA.

Mitigation of isoquercitrin on β-lactoglobulin glycation: Insight into the mechanisms by mass spectrometry and interaction analysis

Formation of advanced glycation end products (AGEs) on foods imposes threats to human health after intaking. This research firstly evaluated the inhibition of isoquercitrin on β-lactoglobulin (β-Lg) glycation, the mechanisms were elucidated by fluorescence spectroscopy, Orbitrap MSⁿ and molecular docking. Fluorescence spectra indicated that isoquercitrin effectively alleviated the formation of AGEs, it could stabilize the conformation structure of glycated β-Lg (G-β-Lg), change the micro-environment in the vicinity of chromophores. SDS-PAGE analysis revealed the suppressed cross-linking of G-β-Lg induced by isoquercitrin. The number of glycation site detected on G-β-Lg was reduced from ten to eight after the addition of isoquercitrin, and the relative glycation degree of substitution of per site (RGDSP) of most glycation sites were also greatly decreased. As indicated by intermolecular interaction, isoquercitrin quenched the fluorescence of β-Lg via a static mechanism, and their combination is an endothermic processing mainly derived by hydrophobic interaction, hydrogen bonds, and van der Waals forces. Isoquercitrin interacted with β-Lg to form an equimolar complex, and one hydrogen bond was formed between isoquercitrin and Lys69 (4.96 Å). Above results proved that isoquercitrin can be a promising anti-glycation agent used in food system to prevent the formation of harmful glycation products.

Observation of the structural changes of α-lactalbumin induced by ultrasonic prior to glycated modification

Bovine α-lactalbumin (BLA) was treated by ultrasonic at 150 W/cm² for different times and subsequently glycated with mannose by dry-heating. Molecular weight, intrinsic fluorescence spectra, glycation sites and degree of modified BLA were observed. The proteinaceous high molecular weight components were formed after ultrasonic prior to glycated modification, while the conformational changes were obvious. Prior to ultrasonic pretreatment, K62, K114, and K122 of BLA were identified. After treated by ultrasound at 150 W/cm² for 5, 10, 15, and 20 min, the sites were increased to four, four, five, and five, respectively. All glycated sites of modified BLA exhibited a higher degree of substitution per peptide (DSP) values compared to native BLA. Ultrasonic at 150 W/cm² for 20 min revealed the most significant change in the BLA structure. Therefore, conformational changes, the intensified glycation site, and DSP value were responsible for the structural changes of BLA. Practical applications BLA is suitable as an ingredient for infant nutrition in food, and has immune-modulating, antioxidant, antibacterial, and antitumor activity etc. This study revealed that the structural changes of BLA induced by ultrasonic prior to glycated modification. It will be beneficial to understand the mechanism of the functional changes of modified BLA. Ultrasonic prior to glycated modification will be more likely to develop a practical technology to modify protein in the food industry, and improve the functional characteristics of food, such as produce hypo-allergenic cow's milk in future.

Reduced IgE/IgG binding capacities of bovine α-Lactalbumin by glycation after dynamic high-pressure microfluidization pretreatment evaluated by high resolution mass spectrometry

Dynamic high-pressure microfluidization (DHPM) pretreatment and glycation with lactose were employed to modify α-Lactalbumin (α-LA) with respect to the IgE/IgG binding capacities. No significant difference on incorporation ratio value of glycated α-LA was observed with and without DHPM pretreatment. However, IgE/IgG binding capacities of α-LA were decreased after glycation and DHPM pretreatment promoted the reduction. The lowest IgE/IgG binding capacities of glycated α-LA were obtained by DHPM pretreatment at 110 MPa. Native α-LA was mainly glycated at K62, K94, K98, whereas glycation sites and degree of substitution per peptide (DSP) were added after DHPM treatment. Therefore, the reduced IgE/IgG binding capacities of α-LA was attributed to the characteristics of glycated sites, including the amount, location, and DSP values. Interestingly, K98 played the most important role in decreasing IgE/IgG binding capacities of α-LA. The study revealed that glycation combined with DHPM was a promising way to decrease the allergenicity of proteins.

[Magnetic-activated cell sorting (MACS) versus density gradient centrifugation (DGC) for the selection of human sperm in assisted reproductive techniques]

Objective: To investigate whether the assisted reproductive techniques (ART) outcomes can be improved by using magnetic-activated cell sorting combined isolate density gradient centrifugation (MACS-DGC), and to compare the results with the conventional isolate density gradient centrifugation (DGC) method. Methods: In the period from January to December 2014, patients who attended the andrology laboratory for sperm DNA fragmentation analysis and underwent the in vitro fertilization and embryo transfer (IVF-ET) treatment were divided into 3 groups, and each group has two subgroups according to the way of fertilization : in vitro fertilization (IVF) as subgroup 1 and intracytoplasmic sperm injection (ICSI) as subgroup 2. Group A (A1, A2 ): DNA fragmentation index(DFI)≥20 and using MACs; Group B (B1, B2): DFI≥20 and using isolate method; Group C (C1, C2): DFI<20 and using isolate method. The fertilization rate, good-quality embryos, implantation rate, pregnancy rate and live-birth rate of each group were analyzed. Results: Similar results were obtained among groups for all the parameters compared: On IVF cycles no significant difference was observed in fertilization rate, percentage of good-quality embryos on day 3, implantation rate, positive beta-hCG tests, and live-birth rate among the three subgroups (A1 vs B1 vs C1). Between the subgroups of ICSI cycles (A2 vs B2 vs C2) the percentage of high-quality embryos, pregnancy rate, implantation rate and live-birth rate were all significantly higher in the MACS-DGC (A2) group compared to DGC alone (B2). Conclusion: Based on the results, MACS as a part of sperm preparation technique will not improve sperm fertilizing potential, embryos quality, implantation rate, pregnancy rate or live-birth rate of IVF, but it may help select the most fertile sperm and to improve clinical outcomes of ICSI.

HPLC-QTOF-MS/MS profiling, antioxidant, and α-glucosidase inhibitory activities of Pyracantha fortuneana fruit extracts

This study was carried out to optimize the solvent for extracting the antioxidants and α-glucosidase inhibitors (AGIs) from Pyracantha fortuneana fruit (PFF) and the major chemical components were characterized by HPLC-QTOF-MS/MS. The results showed that 50% and 70% acetone (v/v, ml/ml) gave the best extraction efficiency on phenolics and total flavonoids, while 70% acetone and 50% methanol possess better recovery on protein and polysaccharides, respectively. In addition, the 50% and 70% acetone extracts gave the strongest radical scavenging ability and α-glucosidase inhibitory activity (p > 0.05), but the Fe³⁺ reducing power of the 50% acetone extract was higher than that of 70% acetone. Correlation analysis indicated that phenolic acids and flavonoids were connected to the antioxidant activity and α-glucosidase inhibitory activity closely. Moreover, 25 compounds including 7 flavonoids, 6 phenolic acids, 7 organic acids, 3 tannins, 1 terpene, and 1 alkaloid were identified or tentatively identified in the 50% acetone extract. Overall, 50% acetone can be a proper solvent for extracting antioxidants and AGIs from PFF. PRACTICAL APPLICATIONS: Imbalance between production and clearance of reactive oxygen species (ROS) in the body could induce various chronic diseases. PFF is an edible fruit beneficial to human health; it is reported to be capable of optimizing blood glucose levels and may prevent premature aging. In the present study, PFF was found to be excellent in antioxidant activities and α-glucosidase inhibitory ability; 50% acetone was found to be the best extraction solvent. In addition, the predominant phytochemical components of the 50% acetone extract were characterized. This study can promote further research of Pyracantha fortuneana in natural functional products, especially in the prevention of type II diabetes and its complication.

Insights into the Mechanism of Quercetin against BSA-Fructose Glycation by Spectroscopy and High-Resolution Mass Spectrometry: Effect on Physicochemical Properties

Quercetin has been reported to suppress protein glycation or the formation of advanced glycation end-products (AGEs), but the inhibition mechanism related to protein structure and glycation sites and the influence on physicochemical properties remain unclear. The aim of the current research was to investigate the mechanism of quercetin against glycation with BSA-fructose as model by spectroscopic and spectrometric techniques. Changes in physicochemical properties were evaluated by antioxidant activity and emulsifying properties. The results indicated that quercetin dose-dependently inhibited the glycation of BSA by attenuating the alteration of conformational structure and microenvironment induced by glycation. It could also suppress the cross-linking or aggregation of glycated BSA, which reflected in the decreased molecular weight determined by SDS-PAGE and MALDI-TOF. Nanoliquid chromatography coupled to Q-Exactive tandem mass spectrometry analysis revealed the mapping of 20, 23, 19, and 19 glycation sites in glycated BSA with 0, 0.5, 1.5, and 3.0 mM quercetin, respectively. Quercetin changed the glycation sites of BSA, but it could not reduce the number greatly. In addition, quercetin reduced the antioxidant ability and increased the emulsifying properties of BSA, while negligible efficiency was observed on the antioxidant activity and emulsifying activity index of glycated BSA.

[Application of lower abdominal aorta balloon occlusion technique by ultrasound guiding during caesarean section in patients with pernicious placenta previa]

Objective: To discuss the feasibility, effect and safety of lower abdominal aorta balloon occlusion technique by ultrasound guiding during caesarean section in patients with pernicious placenta previa. Methods: The clinical data of 40 patients with pernicious placenta previa complicated with placenta accreta from January 2015 to August 2017 in Liuzhou workers hospital were analyzed retrospectively. The study group included 20 cases, which were operated in the way of cesarean section combined lower abdominal aorta balloon occlusion technique by ultrasound guiding, while the control group also included 20 cases, which were operated in the way of the conventional cesarean section without balloon occlusion technique. The bleeding amount, blood transfusion volume, operative total time, hysterectomy and complications of the two groups were compared. Results: The bleeding amount and blood transfusion volume in study group were(850±100)ml and (400±50)ml, which were lower than that of the control group[(2 500±230)ml and (1 500±100)ml], the difference was statistically significant(t=35.624, 16.523, all P<0.05). In addition, the hysterectomy rate in study group was 5%, which was lower than that in the control group(30%), the difference was statistically significant(χ²=8.672, P<0.05). And the total time of operation was (2.0±0.5)h in the study group, which was shorter than that in the control group[(3.5±0.4)h]. The difference was statistically significant(t=11.362, P<0.05). No postoperative complications took place in the study group.The blood pressure, heart rate and blood oxygen fluctuated significantly, and the postoperative renal function was significantly reduced in the control group. Conclusions: The lower abdominal aorta balloon occlusion technique by ultrasound guiding during a caesarean section in patients with pernicious placenta previa can effectively control the bleeding during operation, and preserve reproductive function to the utmost degree.Therefore, the technique is safe, feasible, convenient and cheaper, and worthy of being widely applied in clinic.

[Effect of resection of adenoids and tonsillectomy on immune function in children with obstructive sleep apnea hypopnea syndrome]

Objective:To remove the immune function of children with obstructive sleep apnea hypopnea syndrome by resection of adenoids and tonsillar. Method: The fasting peripheral venous blood of children with OSAHS and healthy children were collected. The lymphocyte subsets, NK cells and immunoglobulin levels were compared between the two groups. The fasting blood samples of OSAHS children were collected again after 2d, 30d, 60d and 90d after operation. The changes of lymphocyte subsets, NK cells and immunoglobulin levels were observed after operation. Result: Before operation, at the 0.05 test level, it was not yet clear that the levels of IgG, IgM, IgA, NK, CD3+, CD4+ and CD8+ in OSAHS children were significantly different from those in the control group. The levels of IgA, CD3+ and CD4+ decreased significantly in children at 2d and OSAHS after operation, and IgG, IgM, IgA, NK, CD3+ and IgA continued to rise after 60d until ninetieth day after operation. Conclusion: There is no statistical disorder of immune level in children with OSAHS compared with healthy children. The implementation of adenoidectomy and tonsillectomy in children with OSAHS, the level of immunity in 90 days can be restored to the preoperative level.

The Mechanism of Decreased IgG/IgE-Binding of Ovalbumin by Preheating Treatment Combined with Glycation Identified by Liquid Chromatography and High-Resolution Mass Spectrometry

Ovalbumin is one of the most important sensitizing ingredients in allergens of egg albumin, which restricts the application of egg in the field of food processing. Previous research has indicated that glycation could cause the protein to partially expand, which may bring about the destruction of the structural IgG and IgE epitopes and induce the decline of the IgG- and IgE-binding ability of ovalbumin. In this research, the effect of a preheating treatment integrated with glycation on the IgG- and IgE-binding capability and the conformation changes of ovalbumin was studied by detecting the glycated sites and the values of degree of substitution per peptide (DSP) by liquid chromatography and high-resolution mass spectrometry (LC-HRMS). Interestingly, we found that a glycation site (K227) attached by two ribose molecules was detected in glycated ovalbumin with preheating treatment. In addition, a new glycation site (K323) appeared in G-60. The results displayed that preheating treament could strengthen the changes in the secondary and tertiary structure of ovalbumin by enhancing glycation and further reduce the IgG/IgE-binding ability by integrating with glycation because of the cover of IgG and IgE epitopes. Therefore, preheating treatment integrated with glycation may offer a way for ovalbumin to reduce sensitization.

[Effect of tympanostomy tube insertion with adenoidectomy for children with recurrent otitis media with effusion]

Objective:To observe the clinical effect of tympanostomy tube insertion with adenoidectomy for children with recurrent otitis media with effusion. Method:One hundred and twenty-six cases of children with recurrent otitis media were randomly divided into observation group and control group(63 in each group), subsequently compared the therapeutic effect of the two groups which observation group had tympanostomy tube insertion with adenoidectomy and the other group had only tympanostomy tube insertion. Result:In terms of the total effective rate,observation group and control group were 96.82% and 76.19% respectively, the difference had statistical significant(P<0.05);compared to control group, the recurrent rate of observation group after treatment was extremely lower, the same as middle ear cavity effusion time, which both had statistical significance (P<0.05); the complete healing time of two groups had no statistical significance(P>0.05). Conclusion:Tympanostomy tube insertion with adenoidectomy has significant treatment effect for children with recurrent otitis media with effusion, it could reduce the recurrent rate after surgery and shorten the time of middle ear cavity effusion.

Maternal plasma levels of cell-free β-HCG mRNA as a prenatal diagnostic indicator of placenta accrete

OBJECTIVE

Several biomarkers, including maternal serum creatinine kinase and α-fetoprotein, have been described as potential tools for the diagnosis of placental abnormalities. This study aimed to determine whether maternal plasma mRNA levels of the β subunit of human chorionic gonadotropin (β-HCG) could predict placenta accreta prenatally.

METHODS

Sixty-eight singleton pregnant women with prior cesarean deliveries (CDs) were classified into three groups: normal placentation (35 women, control group); placenta previa alone (21 women, placenta previa group); and both placenta previa and placenta accreta (12 women, placenta previa/accreta group). Maternal plasma concentrations of cell-free β-HCG mRNA were measured by real-time reverse-transcription polymerase chain reaction and were expressed as multiples of the median (MoM).

RESULTS

Cell-free β-HCG mRNA concentrations (MoM, range) were significantly higher in women with placenta accreta (3.65, 2.78-7.19) than in women with placenta previa (0.94, 0.00-2.97) or normal placentation (1.00, 0.00-2.69) (Steel-Dwass test, P < 0.01 and P < 0.01, respectively). In the placenta previa/accreta group, the concentration of cell-free β-HCG mRNA was significantly higher among women who underwent CDs with hysterectomy (4.41, 3.49-7.19) than among women whose CDs did not result in hysterectomy (3.20, 2.78-3.70) (Mann-Whitney U test, P = 0.012).

DISCUSSION

An increased level of cell-free β-HCG mRNA in the maternal plasma of women with placenta accreta may arise from direct uteroplacental transfer of cell-free placental mRNA molecules.

CONCLUSIONS

The concentration of cell-free β-HCG mRNA in maternal plasma may be applicable to the prenatal diagnosis of placenta accreta, especially to identify women with placenta accreta likely to require hysterectomy.

The presence and expression of the hepatitis B virus in human oocytes and embryos

BACKGROUND

The objective of this study was to explore the potential for vertical transmission of hepatitis B virus (HBV) from parents to offspring via human germ cells.

METHODS

For study samples, 250 oocytes from hepatitis B surface antigen (HBsAg) seropositive women and 578 embryos from couples with at least one HBsAg seropositive partner were collected. HBV DNA in the nuclei of oocytes and embryos was detected by fluorescence in situ hybridization; HBsAg expression was analysed using immunofluorescence; and serum HBV DNA levels were measured by real-time PCR. The HBV infection duration of the women and the serum HBsAg status of their mothers were also examined.

RESULTS

HBV DNA was present in 9.6% (24/250) of oocytes and 14.4% (83/578) of embryos. Rates of HBV DNA positive embryos were similar among couples in which the woman, man or both partners were HBsAg seropositive, 13.1% (57/436), 21.3% (16/75) and 14.9% (10/67), respectively. Rates of positivity in oocytes and embryos were significantly higher in a group with high serum levels HBV DNA than in a group with lower serum levels (P= 0.004 and P= 0.002, respectively). Higher rates of oocyte positivity were found for women whose mothers were HBV infected compared with those with uninfected mothers. Expression of HBsAg was observed in 8.7% (2/28) oocytes and 14.1% (10/71) embryos (P= 0.34).

CONCLUSIONS

The presence of HBV DNA in human oocytes or embryos was related to the women's serum levels of HBV DNA and the infection status of their mothers. The HBV positive embryos were either maternally or paternally dependent. HBV infection may result in vertical transmission to the offspring via germ cells.

New prenylchalcones from the hops of Humulus lupulus

Two new prenylchalcones, xanthohumol C and D, together with two known prenylchalcone derivatives, xanthohumol (1) and 5''-(2''-hydroxyisopropyl)-dihydrofurano-[2'',3''-b]-4,4'-dihydroxy-6'-methoxy-chalcone (4) were isolated and identified from the hops of Humulus lupulus L. The structures of xanhohumol C and D were elucidated as 5''-hydroxy-6'',6''-dimethyl-dihydropyrano-[2'',3''-b]-4,4'-dihydroxy-6'-methoxy-chalcone (2) and 5''-hydroxy-6'',6''-dimethyl-dihydropyrano-[2'',3''-b]-4',6'-dimethoxy-4-hydroxy-chalcone (3) on the basis of HRFAB-MS, 1D and 2D NMR (HMQC, HMBC) spectroscopic data. Among the new prenylchalcones, compound 2 showed marginal cytotoxic activity against human stomach carcinoma BGC-823 and human hepatic carcinoma HepG2 cells.

[Chemical constituents from the tuber of Cremastra appendiculata]

To study the chemical constituents of "Shan-Ci-Gu" (the tuber of Cremastra appendiculata (D. Don) Makino), the compounds were isolated with silica gel and reverse phase silica gel as well as Sephadex column chromatographic method. Their structures were elucidated on the basis of modern spectra technology. Seven compounds were isolated and identified as 5-methoxybibenzyl-3, 3'-di-O-beta-D-glucopyranoside (1), militarine (2), loroglossin (3), protocatechuic acid (4), succinic acid (5), gastrodin (6), and daucosterol (7). Compound 1 is a new compound. Compounds 2 -6 were isolated from this plant for the first time.

[Studies on flavones in of Lavandula augustifolia]

OBJECTIVE

To study on the chemical constituents of Lavandula augustifolia.

METHOD

The compounds were extracted with 95% ethyl alcohol, isolated by various column chromatography and identified by spectroscopic methods.

RESULT

Seven flavanoids were isolated and identified as apigenin (1), ladanein (2), apigenin-7-O-beta-D-(6'-p-hydoxy-cinnamoyloxy) -mannoside (3), luteolin (4), apigenin-7-O-beta-D-glucoside (5), luteolin-7-O-beta-D-glucoside (6), 5, 4'-dihydroxy flavonoid-7-O-beta-D-pyranglycuronate buthyl ester (7).

CONCLUSION

All of these seven compounds were obtained from this plant for the first time.

Antifungal and new metabolites of Myrothecium sp. Z16, a fungus associated with white croaker Argyrosomus argentatus

AIMS

Fungal infection is still a life-threatening risk for the immunocompromised population such as AIDS patients and those who receive treatments with immunosuppressors and/or frequent administrations of wide-spectrum antibiotics, which inevitably lead to the drug resistance and unbalanced microflora populations. The present work was accordingly performed to characterize more potent antifungal metabolites from various cultures of marine fungi residing in white croaker Argyrosomus argentatus.

METHODS AND RESULTS

The three most common opportunistic human pathogens Candida albicans (CCCCM ID 00148), Aspergillus niger (CCCCM ACCC 30005) and Trichophyton rubrum (CCCCM ID 00001) were selected as test fungi. A total of 16 cultivable fungal strains were isolated from the variant tissues of Ar. argentatus collected from the Yellow Sea, followed by preliminary antifungal screenings of the EtOAc extracts of the corresponding cultures. As a result, the inhibition of the three target fungi, plus being allergic to isolators' skin, were discerned with the EtOAc extract of the fungus under the isolation number Z16 that was identified subsequently as Myrothecium sp. by a combination of morphological and 18S rDNA finger-typing characteristics. A follow-up bioassay fractionation of the EtOAc extract, in conjunction with spectral analyses [MS, (1)H-NMR, (13)C-NMR, distortionless enhancement by polarization transfer (DEPT), heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond resonance (HMBC)] wherever required, afforded eventually the characterization of a new acid (compound 1: 4,5-ditridecyl-octanedioic acid), three macrocyclic trichothecenes including roridin A (compound 2), verrucarin A (compound 3) and 8beta-acetoxy-roridin H (compound 4), (22E,24R)-cerevisterol (compound 5) and N-phenyl-beta-amino-naphthalene (compound 6). In vitro antifungal tests showed that the three trichothecenes were active against A. niger, T. rubrum and C. albicans with MICs of 31.25, 62.5 and 125 microg ml(-1) for compound 2, 250, 125 and 31.25 microg ml(-1) for compound 3 as well as 125, 62.5 and 125 microg ml(-1) for compound 4 respectively. The MICs of ketoconazole (co-assayed herewith as a positive reference) against A. niger, T. rubrum and C. albicans were 31.25, 250, 31.25 microg ml(-1) respectively. A preliminary structure-activity relationship of the antifungal trichothecenes was highlighted in brief.

CONCLUSIONS

The present investigation demonstrated that marine fungus Myrothecium sp. Z16 associated with white croaker (Ar. argentatus), was an efficient producer of a new acid and antifungal trichothecenes, the latter presumably being also the allergic substances in the culture.

SIGNIFICANCE AND IMPACT OF THE STUDY

The title marine fungus was investigated to be a resource of new aliphatic acid, and trichothecenes with potent antifungal and dermal toxic actions.

Regioselective sonochemical synthesis of genistein derivatives

Differential functionalization of the phenolic groups in genistein was carried out in excellent yields under ultrasonic irradiation. The isoflavone ring had proved to be unstable under stirring at 60 degrees C and phenyl benzyl ketone was unexpectedly isolated instead of the genistein derivative.

New and cytotoxic anthraquinones from Pleospora sp. IFB-E006, an endophytic fungus in Imperata cylindrical

In addition to 7-methoxy-2-methyl-3,4,5-trihydroxyanthraquinone (1), physcion (2), macrosporin (3), deoxybostrycin (4), altersolanol B (5) and dactylariol (6), a new hexahydroanthraquinone named pleospdione (7) was isolated from the culture of Pleospora sp . IFB-E006, an endophytic fungus residing in the normal stem of Imperata cylindrical (Gramineae). Structure determination of pleospdione was accomplished using IR, HR-ESI-MS, 1D and 2D NMR spectral analysis. Compounds 4 - 6 exhibited significant cytotoxic activity against human colon cancer (SW1116) and leukemia (K562) cell lines while compounds 1, 2 and 7 were only weakly or moderately active.

DEPBT as an efficient coupling reagent for amide bond formation with remarkable resistance to racemization

3-(Diethoxyphosphoryloxy)-1, 2, 3-benzotriazin-4(3H)-one (DEPBT) is an effective coupling reagent for synthesis of linear and cyclic peptides by both solution and solid-phase peptide synthesis. DEPBT mediates amide bond formation with remarkable resistance to racemization. When DEPBT is used as a coupling reagent, it is not necessary to protect the hydroxy group of the amino component (such as tyrosine, serine, and threonine) and the imidazole group in the case of histidine. The high efficiency of DEPBT and its utility have been demonstrated in the syntheses of complex natural products such as ramoplanin A2, ramoplanose aglycon, ustiloxin, and teicoplanin aglycon.

Endophytic naphthopyrone metabolites are co-inhibitors of xanthine oxidase, SW1116 cell and some microbial growths

Fractionation of the extract of Aspergillus niger. IFB-E003, an endophyte in Cyndon dactylon, gave four known compounds naphtho-gamma-pyrones rubrofusarin B, fonsecinone A, asperpyrone B and aurasperone A, which were further investigated biologically. Rubrofusarin B was shown to be cytotoxic to the colon cancer cell line SW1116 (IC50: 4.5 microgml-1), and aurasperone A inhibitory on XO (xanthine oxidase) (IC50: 10.9 micromoll-1). Moreover, the four naphtho-gamma-pyrones exhibited growth inhibitions against the five test microbes with MICs ranging in between 1.9 and 31.2 microgml(-1). The present recognition of rubrofusarin B and aurasperone A as strong co-inhibitors on XO, colon cancer cell and some microbial pathogens is of significance for the imperative discovery of new relevant therapeutic agents.

Studies on the synthesis of cyclic pentapeptides as LHRH antagonists and the factors that influence cyclization yield

Six cyclic pentapeptides containing two or three non-protein amino acids have been synthesized by cyclization of linear precursors in dilute solution and characterized by TLC. HPLC, NMR, melting point. specific rotation etc. A total of 72 cyclization reactions were carried out to study the factors that influence head-to-tail cyclization: linear precursor sequence, coupling reagent, residue configuration, the proportion of DMAP additive, concentration, reaction temperature and reaction time. The cyclic pentapeptides will be modified by active moieties and evaluated as LHRH antagonists.

Recent progress on immobilization of enzymes on molecular sieves for reactions in organic solvents

Enzymes exhibit high selectivity and reactivity under normal conditions but are sensitive to denaturation or inactivation by pH and temperature extremes, organic solvents, and detergents. To extend the use of these biocatalysts for practical applications, the technology of immobilization of enzymes on suitable supports was developed. Recently, these immobilized biomolecules have been widely used and a variety of immobilization supports have been studied. The majority of these supports cover diverse kinds of materials such as natural or synthetic polyhydroxylic matrixes, porous inorganic carriers, and all kinds of functional polymers. Microporous molecular sieve, zeolite, has attracted extensive interest in research because of its distinctive physical properties and geochemistry. Recently, with the discovery of a new family of mesoporous molecular sieves, MCM-41, this series of materials shows great potential for various applications. Molecular sieves involve such a series of materials that can discriminate between molecules, particularly on the basis of size. As support materials, they offer interesting properties, such as high surface areas, hydrophobic or hydrophilic behavior, and electrostatic interaction, as well as mechanical and chemical resistance, making them attractive for enzyme immobilization. In this article, different types of molecular sieves used in different immobilization methods including physical adsorption on zeolite, entrapment in mesoporous and macroporous MCM series, as well as chemically covalent binding to functionalized molecular sieves are reviewed. Key factors affecting the application of this biotechnology are discussed systematically, and immobilization mechanisms combined with newly developed techniques to elucidate the interactions between matrixes and enzyme molecules are also introduced.

Synthesis of N-protected peptide alcohols catalyzed by subtilisin or alpha-chymotrypsin in organic solvents

A series of N-protected peptide alcohols were synthesized using amino alcohols with unprotected hydroxy groups as amino components by the catalysis of subtilisin or alpha-chymotrypsin in organic solvents. N-protected aromatic amino acid esters were more suitable as acyl donors for subtilisin. The influences of different N-protecting groups, organic solvents, and content of water on synthesis of N-protected peptide alcohols were systematically studied.

[Study of distribution and metabolism of methamphetamine in hair of guinea pig]

OBJECTIVE

To study the distribution and metabolism of methamphetamine in the hair of guinea pig.

METHODS

Determination of methamphetamine and its metabolite amphetamine in hair was performed by GC/MS and GC/NPD. Concentration-time course of methamphetamine and amphetamine in hair of guinea were recorded. Relationship between hair color, administrated dose and drug concentration in hair were also discussed.

RESULTS

The concentration of amphetamine is higher than the concentration of methamphetamine in the hair of guinea administrated a single dose or seven doses of methamphetamine. The concentration of methamphetamine and amphetamine were significantly related with administration dose and the incorporation rate into white and brown hair is much poorer than that of black hair.

CONCLUSION

Administration methods, dose and the color of hair affect the concentration of methamphetamine and amphetamine.

3-(Diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one (DEPBT): a new coupling reagent with remarkable resistance to racemization

[formula: see text] The new crystalline phosphate reagent 3-(diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one (DEPBT) mediates amide bond formation with a remarkable resistance to racemization. Comparative racemization studies were carried out and DEPBT proved to be superior to typical phosphonium and uronium coupling reagents. DEPBT is easily prepared and is exceedingly stable with a shelf life of months at room temperature. The advantageous properties of DEPBT render it a useful and unique addition to the arsenal of coupling reagents.

Influence of reaction conditions on syntheses of sweetener precursors catalyzed by thermolysin in tert-amyl alcohol

The activity of enzymes to form a peptide bond in organic solvent was greatly influenced by observed pH and water content. The precursors of two sweeteners, P-Asp-Xaa-OR (P=Z or For, Xaa-OR=Phe-OMe or Ala-OcHex), were synthesized by enzyme, and the reaction conditions were studied systematically. Z-Asp-OH was coupled with H-Phe-OMe or H-Ala-OcHex by thermolysin in tert-amyl alcohol. The best coupling results were obtained when the optimized observed pH was 8 or 9, and the water content was about 6% (V/V). The protecting group Z is better than For under the reaction conditions and H-Phe-OMe is a better nucleophile than H-Ala-OcHex. The expected optically pure peptides were obtained when the racemic amino acids were used as amino components in the starting materials. The physical constants of P-Asp-Xaa-OR synthesized by thermolysin are identical with those of peptides synthesized by chemical method.

Isolation and characterization of a group of oligopeptides related to oxidized glutathione from the root of Panax ginseng

Six gamma-glutamyl oligopeptides were isolated for the first time from aqueous methanol extracts of Panax ginseng root by using column chromatography on ion-exchange resin, gel filtration and reverse-phase high-performance liquid chromatography. Their structures had been established with the methods of amino acid analysis, N-terminal, C-terminal determination and double-coupling sequence analysis. They were: P-I (N-gamma-glutamylcystinyl-bis-glycine), P-ll (gamma-glutamylcysteinylglycine disulfide, oxidized glutathione), P-III (N,N'-bis-gamma-glutamylcystinylglycine), P-IV (gamma-glutamylcysteinylglycinamide disulfide), P-V (N-gamma-glutamylglycylcysteine disulfide), P-VI(gammaglutamylarginine); five of them are related to oxidized glutathione. The structures were further confirmed by the chemical synthesis. As far as we know, P-V (N-gamma-glutamylglycylcysteine disulfide) is a new biologically active peptide which exhibits somnogenic effect and is more potent than that of P-II.

Studies on the neuroexcitotoxin beta-N-oxalo-L-alpha,beta-diaminopropionic acid and its isomer alpha-N-oxalo-L-alpha,beta-diaminopropionic acid from the root of Panax species

The neuroexcitotoxic nonprotein amino acid, beta-N-oxalo-L-alpha,beta-diaminopropionic acid (beta-N-ODAP) was found in Panax species such as Panax ginseng 'C.A. Meyer' (cultivated in Northeastern China), Panax quinquefolius (L), Panax notoginseng 'F.H. Chen' (cultivated in Southwestern China), Korean red ginseng and Jilin (China) red ginseng. beta-N-ODAP was verified to be a natural substance, and its isomer alpha-N-oxalo-L-alpha,beta-diaminopropionic acid (alpha-N-ODAP) is very likely an artifact generated during the separation process. The interconversion between beta-N-ODAP and alpha-N-ODAP was observed. Results showed that both beta-N-ODAP and alpha-N-ODAP can easily be converted into their isomers at higher temperature or in acidic and basic solution. Their interconversion equilibrium constant and rate constants were obtained. Upon extensive study and a good understanding of the interconversion, accurate physical constants and spectroscopic data such as MS, 1H NMR, 13C NMR and UV were obtained.