Transition-metal-free radical difluorobenzylation/cyclization of unactivated alkenes: access to ArCF2-substituted ring-fused quinazolinones.

A mild and efficient transition-metal-free radical difluorobenzylation/cyclization of unactivated alkenes toward the synthesis of difluorobenzylated polycyclic quinazolinone derivatives with easily accessible α,α-difluoroarylacetic acids has been developed. This transformation has the advantages of wide functional group compatibility, a broad substrate scope, and operational simplicity. This methodology provided a highly attractive access to pharmaceutically valuable ArCF2-containing polycyclic quinazolinones.

Transition-metal catalyzed oxidative spirocyclization of N-aryl alkynamides with methylarenes under microwave irradiation.

A practical synthetic route to construct a variety of 3-benzyl spiro[4,5]trienones was developed via transition-metal Cu/Ag-catalyzed oxidative ipso-annulation of activated alkynes with unactivated toluenes using TBPB as an oxidant under microwave irradiation. This method allows the formation of two carbon-carbon bonds and one carbon-oxygen bond in a single reaction through a sequence of C-H oxidative coupling, ipso-carbocyclization and dearomatization. The advantages of this protocol are its operational simplicity and broad substrate scope, and the ability to afford the desired products in moderate to good yields.

Silver-catalyzed direct C-H oxidative carbamoylation of quinolines with oxamic acids.

A silver-catalyzed efficient and direct C-H carbamoylation of quinolines with oxamic acids to access carbamoylated quinolines has been developed through oxidative decarboxylation reaction. The reaction proceeds smoothly over a broad range of substrates with excellent functional group tolerance and excellent yields under mild conditions.

Metal-free oxidative coupling of quinoxalin-2(1H)-ones with arylaldehydes leading to 3-acylated quinoxalin-2(1H)-ones.

A facile TBHP-mediated direct oxidative coupling of quinoxalin-2(1H)-ones with arylaldehydes has been developed under metal-free conditions. This method provided a convenient and efficient approach to various 3-acylated quinoxalin-2(1H)-ones from readily available starting materials with excellent regioselectivity. This reaction proceeded efficiently under mild conditions over a broad range of substrates and with functional group tolerance.

Silver catalysed decarboxylative alkylation and acylation of pyrimidines in aqueous media.

Decarboxylative alkylation or acylation reactions of simple pyrimidines have been developed in aqueous media. Using aliphatic carboxylic acids or 2-oxocarboxylic acids and pyrimidines as substrates and silver as the catalyst, the 4-substituted alkyl or acyl pyrimidines were isolated in moderate to good yields.

Silver-catalyzed radical tandem cyclization: an approach to direct synthesis of 3-acyl-4-arylquinolin-2(1H)-ones.

A silver-catalyzed efficient and practical synthesis of 3-acyl-4-arylquinolin-2(1H)-ones or 3-acyl-4-aryldihydroquinolin-2(1H)-ones through intermolecular radical addition/cyclization in aqueous solution is reported. This method provides a novel, highly efficient, and straightforward route to substituted quinolin-2-ones or 3,4-dihydroquinolin-2-ones in one step. A possible mechanism for the formation of quinolin-2-ones is proposed.

Effects of organic selenium on lead-induced impairments of spatial learning and memory as well as synaptic structural plasticity in rats.

To study the effect of organic Se on spatial learning and memory deficits induced by Pb exposure at different developmental stages, and its relationship with alterations of synaptic structural plasticity, postnatal rat pups were randomly divided into five groups: Control; Pb (Weaned pups were exposed to Pb at postnatal day (PND) 21-42); Pb-Se (Weaned pups were exposed to Se at PND 43-63 after Pb exposure); maternal Pb (mPb) (Parents were exposed to Pb from 3 weeks before mating to the weaning of pups); mPb-Se (Parents were exposed to Pb and weaned pups were exposed to Se at PND 43-63). The spatial learning and memory of rat pups was measured by Morris water maze (MWM) on PND 63. We found that rat pups in Pb-Se group performed significantly better than those in Pb group (p<0.05). However, there was no significant difference in the ability of spatial learning and memory between the groups of mPb and mPb-Se (p>0.05). We also found that, before MWM, the numbers of neurons and synapses significantly decreased in mPb group, but not in Pb group. After MWM, the number of synapses, the thickness of postsynaptic density (PSD), the length of synaptic active zone and the synaptic curvature increased significantly in Pb-Se and mPb-Se group; while the width of synaptic cleft decreased significantly (p<0.05), compared to Pb group and mPb group, respectively. However, the number of synapses in mPb-Se group was still significantly lower than that in the control group (p<0.05). Our data demonstrated that organic Se had protective effects on the impairments of spatial learning and memory as well as synaptic structural plasticity induced by Pb exposure in rats after weaning, but not by the maternal Pb exposure which reduced the numbers of neurons and synapses in the early neural development.

Selectfluor-mediated tandem cyclization of enaminones with diselenides toward the synthesis of 3-selenylated chromones.

A practical and metal-free approach for the regioselective selenation of chromones employing Selectfluor reagent under mild conditions is described. The developed method is suitable for a wide substrate scope and affords 3-selenylated chromones in good to excellent yield with high selectivity. An ionic mechanism is proposed for this transformation. Furthermore, the application of potassium thiocyanate with enaminones for the synthesis of thiocyano chromones in this transformation is also successful.

Fecal microbiota transplantation relieves abdominal bloating in children with functional gastrointestinal disorders via modulating the gut microbiome and metabolome.

OBJECTIVE: To evaluate the efficacy and safety of fecal microbiota transplantation (FMT) in functional gastrointestinal disorders (FGIDs) in children with abdominal bloating and changes in their gut microbiome and metabolome. METHODS: Twelve pediatric FGID patients with predominant abdominal bloating who underwent FMT were enrolled in the study. Fourteen healthy controls and four stool donors were included for analysis. Clinical responses were assessed at 8 weeks after FMT. Fecal bacterial composition was determined by 16S rRNA gene sequencing. The fecal metabolome was measured by targeted metabolomics analysis. RESULTS: Median age of the 12 children with FGIDs was 6 years, and nine were boys. Abdominal bloating was relieved in all patients by FMT at 8 weeks. Meanwhile, FMT significantly improved abdominal pain and diarrhea. The a diversity was significantly lower in the FGID patients, while the fecal microbial community (ß diversity) separated from that of healthy control (HCs). The relative abundances of multiple bacterial genera were significantly changed in the feces of the pediatric FGID patients. The levels of several short-chain fatty acids were lower, and lactic acid level was higher in FGID patients than in HCs. Altered bacterial composition was correlated with changes in the fecal metabolite profile and clinical symptoms in FGID patients. FMT modulated fecal microbiome and metabolome in FGID children toward a healthy state. CONCLUSIONS: FMT relieves abdominal bloating and modulates fecal microbiome and metabolome toward a healthy state in children with FGIDs. FMT may provide an alternative therapy for children with FGIDs and abdominal bloating.

[A genome-wide screen for promoter-specific sites of differential DNA methylation during human cell malignant transformation in vitro].

OBJECTIVE: To explore potential epigenetic biomarkers for toxic effects, tumor-related chemical prevention and biological monitor by a genome-wide screening for differential DNA methylation during human cell malignant transformation in vitro. METHODS: The two in vitro cell transformation models included B(a)P-induced human bronchial epithelial cell introduced by H-Ras (HBER) cell transformation and simian vacuolating virus 40 small T antigen induced (SV40 ST-induced) HBER cell transformation. Methylated genes were collected by methylated DNA immunoprecipitation and whole genome amplification (MeDIP-WGA) at three time points during cell transformation which represented different transformation stage. Then, CpG island microarray was used to screen differentially methylated genes. The mRNA levels of hypermethylated genes were also observed by RT-PCR. RESULTS: The CpG island microarray showed that the number of hypermethylated genes in HBER, HBERNT, HBERT cells were 733, 661 and 738 respectively.83 genes were hypermethylated in pre-transformed cell and transformed cell. Moreover, 25 of 83 genes were also hypermethylated in SV40 ST-transformed cell (HBERST). We further confirmed that the mRNA expression of six of these 25 genes, namely family with sequence similarity 178, member A (FAM178A), retinoic acid receptor responder (tazarotene induced) (RARRES1), ubiquitin specific peptidase 28 (USP28), Scm-like with four mbt domains 2 (SFMBT2), family with sequence similarity 59, member A (FAM59A) and nuclear receptor subfamily 4, group A, member 3 (NR4A3) were suppressed during B(a)P-induced transformation. CONCLUSION: The abnormal hypermethylation of specific genes was a common event in the two kinds of human cell transformation models, which shed light on the study for chemical exposure monitor and tumor-related epigenetic biomarkers.

[Differences of clinical manifestations from cytomegalovirus infection in children of various age groups].

OBJECTIVE: Newborns have been the focus group for most studies of cytomegalovirus infection. The objective of the study is to share some preliminary analysis on clinical manifestation differences resulting from cytomegalovirus infection in children of various age groups. METHODS: The clinical data of 108 children with cytomegalovirus infection were retrospectively reviewed. The children were classified into three age groups: <6 months, 6-12 months and >12 months. The differences in clinical manifestations from cytomegalovirus infection among the three age groups were identified. RESULTS: Each age group carried distinctive differences in the occurrence of hepatic damage, jaundice, pneumonia, and hematological manifestations, as well as incidence rate of malformation (p<0.05 or 0.01). The primary clinical manifestations of group<6 months old were hepatic damage(83%), pneumonia(47%) and jaundice (43%). There was a similar proportion of anicteric-hepatitis and icteric-hepatitis; however a low incidence rate of hematological disease (6%) was found in group<6 months old. The primary clinical manifestations of group 6-12 months old were hepatic damage (86%), mostly with no presence of jaundice, pneumonia (33%), and hematological disease (20%). Hepatic damage (52%) and hematological disease (33%) were leading clinical symptoms in group>12 months old where jaundice and pneumonia were rare events. CONCLUSIONS: End-organ damage triggered by cytomegalovirus infection is related to the age of the affected children closely.

Hematochezia in a Child With Heiner Syndrome.

Heiner syndrome (HS) is a food hypersensitivity disease that is mostly caused by cow's milk. The main features may include chronic or recurrent respiratory syndromes, pulmonary infiltrates on radiography, and even pulmonary hemosiderosis. However, gastrointestinal symptoms are rare in HS, which can lead to a misdiagnosis when the chief complaint is about the gastrointestinal system. Here, we report a case of HS complicated by severe hematochezia.

[Establishment and application of oncogene over expressed human epithelial cell transformation model].

OBJECTIVE: To establish human bronchial epithelial cell lines over expressing oncogene and to investigate its application in detection of carcinogen-induced cell transformation. METHODS: Mediated by retrovirus infection, human telomerase catalytic subunit, hTERT was introduced into immortal human bronchial epithelial cells (16HBE) and followed by introduction of the oncogenic allele H-Ras(V12), or c-Myc or empty vector, creating cell lines 16HBETR, 16HBETM and 16HBETV, respectively. Biological characteristics of these cell lines including morphology, proliferation, and chromosomal aberration were examined to access whether they were transformed. Soft agar experiment and nude mice subcutaneous injection were performed using pre-transformed 16HBE cells induced by known carcinogens, nickel sulfate (NiSO4) and 7, 8, -dihydrodiol-9, 10-epoxide benzo[a] pyrene (BPDE). RESULTS: With detection of telomerase activity and Western blotting, the expression of target proteins was verified. Thus, the transgenic 16HBE cell lines were successfully established. Cells expressing oncogene H-Ras or c-Myc grew 30.3% or 10.4% faster than control cells. However, these cells failed to form colonies in soft agar or form tumor in nude mice. 16HBETR, 16HBETM cells obtained transformed phenotype at 5 wks, 11 wks, respectively after treatment with BPDE, which are 15 wks and 9 wks earlier than control cells 16HBETV (20 wks). Meanwhile, 16HBETR, 16HBETM cells obtained transformed phenotype at 11 wks, 14 wks, respectively after treatment with nickel sulfate, which are 21 wks and 18 wks earlier than control cells (32 wks). CONCLUSION: With the advantage of shorter latency, transgenic human cell transformation models could be used in potent carcinogen screening and applied to chemical-carcinogenesis mechanism study.

Safety of fecal microbiota transplantation in Chinese children: A single-center retrospective study.

BACKGROUND: Fecal microbiota transplantation (FMT) is the administration of fecal bacterial liquid from healthy donors to a recipient's digestive tract, which is recommended as a therapeutic method for recurrent Clostridium difficile infection (CDI). Many clinical trials focusing on different diseases are in progress. To date, scarce research and long-term follow-up have been conducted on FMT in children or on the proper guidelines. Our center first performed FMT to treat a 13-month-old boy with severe CDI in 2013. Until February 2018, our center had performed 114 pediatric FMT procedures in 49 subjects. AIM: To investigate the safety of FMT in children. METHODS: A retrospective study was conducted on 49 patients who underwent 114 FMT treatments at our hospital. All FMT processes followed uniform standards. Adverse events (AEs) related to FMT were divided into short-term (48 h post-FMT) and long-term (3 mo). All potential influencing factors for AEs, such as gender, age, time of FMT infusion, route of administration, disease type, immune function state, and donor relative genetic background, were analyzed as independent factors. The significant independent factors and risk ratio with 95% confidence interval (CI) were assessed by multivariate logistic regression analysis. RESULTS: Forty-nine patients (mean age 68.1 mo, range 4 to 193 mo) were recruited. Their average follow-up time after the first FMT was 23.1 mo. The incidence of short-term AEs was 26.32% (30/114). The most common short-term AEs were abdominal pain, diarrhea, fever, and vomiting, which were all self-limited and symptom-free within 48 h. Two severe AEs occurred, and one patient died in the fourth week after FMT. All-cause mortality was 2.04%. As independent factors, age (P = 0.006) and immune state (P = 0.002) had significant effects. Age greater than 72 mo seemed to be correlated with more AEs than age 13 to 36 mo (P = 0.04). In multivariate logistic regression analysis, immune state was an independent risk factor for AE occurrence (P = 0.035), and the risk ratio in immunodeficient patients was 3.105 (95%CI: 1.080-8.923). CONCLUSION: Although FMT was proven to be tolerated in children, we need to be more cautious with immunodeficient patients. The effect on children's long-term health is unpredictable.

Hydrolase-catalyzed Michael addition of imidazoles to acrylic monomers in organic medium.

Hydrolase-catalyzed Michael addition of imidazole derivatives to acrylic monomers in organic medium was described. A serial of N-substituted imidazole derivatives were successfully synthesized in moderate yields by the catalysis of hydrolases in organic medium. Nine commercially available hydrolases from different sources were screened and all of them were found to be able to catalyze this type of addition reaction. The reaction yields depended on the solvent properties and the solvents with higher log P value supported this enzyme-catalyzed reaction to give higher conversion. Influence of the structure of the Michael acceptor and donor on the enzymatic Michael addition was also investigated. The acceptor with shorter alcohol chain afforded a higher yield. A more rapid conversion was observed when the donor had an electron-withdrawing group. This hydrolase-catalyzed Michael addition reaction has widened the applicability of biocatalysts in organic and bioorganic synthesis.

[Construction of thr461 --> Asn461 and Ile462 --> Val462 mutation vector of P4501A1 gene].

OBJECTIVE: To construct Thr461 --> Asn461 and Ile462 --> Val462 mutation vector of P4501A1 gene and to provide scientific base for deeply researching on the function of cytochrome 1A1 gene (CYP1A1) and the mechanism of carcinogenesis. METHODS: According to cDNA sequence of human CYP1A1 gene, universal primers (Pm3/Pm4) and mutant primers (Pt15/Pt16 and Pt17/Pt18) containing restriction enzyme site and mutation site were designed. The first set of primers involving Pm3/Pt16 and Pm3/Pt18 amplified a forward 1.5kb fragment from pGEM-T-CYP1A1 plasmid. The second set of primers involving Pt15/Pm4 and Pt17/Pm4 amplified a reverse 177-bp fragment from 10ng pGEM-T-CYP1A1 plasmid. The third set of primers involving Pm3/Pm4 amplified a 1.5kb fragment from the fomer PCR amplifications. The third PCR products were separated, purified and recovered from 1% agarose gel, then inserted into pMD-T vector. Subsequently the conjunct products were transformed into E. coil strain DH-5alpha., then the single clone was screened out and plasmids were extracted from such clone finally verified by restriction endonuclease analysis and sequencing. RESULTS: A 1.5kb fragment of tricycle PCR amplifications were digested by restriction endonucleases (BamHI and SailI) and sequenced bidirectionally by universal primers(T7p and SP6). The results verified that the cloned fragment including Asn461 and Val462 mutant site had 99.9% homology with the human cDNA of CYP1A1 gene in Genebank. CONCLUSION: The objective fragment containing Asn461 and Va462 mutant site with cDNA of the CYP1A1 gene has been successfully constructed in this experiment.

Ultrasound-accelerated enzymatic synthesis of sugar esters in nonaqueous solvents.

Comparative studies of enzymatic synthesis of glucose esters under ultrasound and shaking were carried out in nonaqueous media. The influence of solvents, enzymes, chain length of the acyl donors, the power of the ultrasound bath, and intermittent ultrasound on the enzymatic synthesis was investigated. Among the eight solvents selected, pyridine was the most appropriate with alkaline protease from Bacillus subtilis whether under ultrasound or shaking. The acceleration effect of ultrasound with Novozym 435 and the alkaline protease from B. subtilis-catalyzed transesterification increased with the chain length of acyl donors, decreasing from C(10) to C(4). We also investigated the influence of the power (50, 100, and 120 W) of the ultrasound irradiation and the manner of operation (continuous ultrasound, 10 min ultrasound/20 min shaking without ultrasound) on the transesterification. The results showed that higher power and continual operational gave the better acceleration. Ultrasound did not change the character and selectivity of the enzyme in the transesterification.

Regioselective monoacylation of cyclomaltoheptaose at the C-2 secondary hydroxyl groups by the alkaline protease from Bacillus subtilis in nonaqueous media.

Transesterification of cyclomaltoheptaose (beta-CD) with divinyl butanedioate, divinyl hexanedioate, and divinyl decanedioate, catalyzed by the alkaline protease from Bacillus subtilis in anhydrous DMF for 5 days, furnished the corresponding vinyl-beta-CD derivatives. The products were characterized by ESI-MS, (1)H NMR, (13)C NMR, IR, and DSC. The results indicated the products to be monosubstituted esters, with monoacylation occurring at the C-2 secondary hydroxyl groups of beta-CD. The regioselectivity of the monoacylation as catalyzed by alkaline protease was not affected by the chain length of the acyl donor.

Regiospecific alkaline protease-catalyzed divinyl acyl transesterifications of primary hydroxyl groups of mono- and di-saccharides in pyridine.

This paper describes highly selective transesterification reactions, catalyzed by an alkaline protease from Bacillus subtilis in pyridine, of several mono- and di-saccharides with divinyl dicarboxylates ranging from 4 to 10 carbon atoms. A series of polymerizable vinyl fatty acid sugar esters were obtained with good selectivity and high yields. Most products had high proportions of the alpha anomer. The influences of the enzymes, solvents, temperature, and acyl donor chain length on the reaction were studied. Vinyl sugar esters offer a new family of functional water-soluble monomers for preparation of sugar-containing polymers.

Silver-catalyzed radical tandem cyclization for the synthesis of 3,4-disubstituted dihydroquinolin-2(1H)-ones.

A silver-catalyzed tandem decarboxylative radical addition/cyclization of N-arylcinnamamides with aliphatic carboxylic acids is reported. This method affords a novel and straightforward route to various 3,4-disubstituted dihydroquinolin-2(1H)-ones in aqueous solution.