N-Aryl glycines as versatile initiators for various polymerizations

N-(1-Pyrenyl)glycine can act as a versatile initiator for various polymerizations.

Necrotizing lymphadenitis : A case report and literature review

BACKGROUND

Necrotizing lymphadenitis is a rare disease. It is often misdiagnosed because of the lack of typical clinical manifestations. It is worth noting that necrotizing lymphadenitis may be a precursor lesion of systemic lupus erythematosus or tumours, so regular follow-up is needed to facilitate early diagnosis. Here, we report a case and conduct a literature analysis summarizing the clinical features of necrotizing lymphadenitis and its treatment and management practices.

CASE PRESENTATION

A 16-year-old young woman presented with fever and lymphadenopathy as the main clinical manifestations, accompanied by a rash during fever that disappeared as the fever subsided. After completing imaging and laboratory examinations, we excluded other diseases such as infections, autoimmune diseases, and malignant tumours. Finally, we diagnosed the patient with necrotizing lymphadenitis based on the results of lymph node biopsy. The symptoms of the patient improved after glucocorticoid treatment, and she was followed up for half a year without recurrence of symptoms.

CONCLUSION

In the clinic, young women with fever and lymphadenopathy as major symptoms should be screened for necrotizing lymphadenitis to facilitate early diagnosis and treatment. Although necrotizing lymphadenitis is self-limiting, its clinical manifestations are similar to those of many diseases. Therefore, it is easily misdiagnosed. An in-depth understanding of the disease is conducive to early diagnosis and treatment in the clinic, thereby reducing further damage to the body and reducing unnecessary evaluation and treatment.

[Analysis of clinical characteristics and drug treatment of inflammatory bowel disease in children: a single center study]

Objective: To analyze the clinical characteristics and efficacy of drug treatment in children with inflammatory bowel disease (IBD) at different ages of onset. Methods: The clinical data of 87 children with IBD admitted to Department of Gastroenterology in Children's Hospital, Capital Institute of Pediatrics from January 2009 to December 2018 were collected. The patients were divided into four groups according to the age of onset: 0 -<2 years old group (36 cases), 2 -<6 years old group (10 cases), 6 -<10 years old group (12 cases) and 10 -<18 years old group (29 cases). The clinical manifestations, laboratory examination, endoscopic findings, pathologic and genetic changes, and treatment were compared among different age groups with chi-square test or Fisher's exact text. Results: (1) A total of 87 patients were diagnosed with IBD, including 50 Crohn's disease (CD) (57%), 25 ulcerative colitis (UC) (29%) and 12 unclassified inflammatory bowel disease (IBD-U) (14%). (2) Patients with fever accounted for 78% (28/36) and 8/10 in the 0 -<2 years old group and 2 -<6 years old group, respectively. Patients with abdominal pain and perianal diseases accounted for 6% (2/36) and 47% (17/36) in the 0 -<2 years old group, and their proportions were significantly different among the four groups (χ(2)=8.369, 40.317 and 13.130, all P<0.05). (3) Leukocytosis, thrombocytosis and anemia were more common in the 0-<2 years old group, seen in 72% (26/36), 31% (11/36) and 81% (29/36), respectively. There were significant differences in the changes of complete blood count among the four groups (χ(2)=21.919, 8.095 and 11.520, all P<0.05). (4) Colonic involvement accounted for 85% (17/20) in the 0 -<2 years old CD patients. While in the CD patients over 6 years old, 61% (14/23) had inflammation of ileum and colon, with a significant difference compared to that in patients under 6 years old (19% (5/27) , χ(2)=9.455, P=0.003). Also, the location of bowel inflammation among the four groups were significantly different (χ(2)=21.120, P<0.01). (5) Noncaseating granulomas were found in 15 (30%) CD patients, and crypt abscess was found in 11 (44%) UC patients. (6) Among the 24 patients whose genes were analyzed by high throughput sequencing, 12 had pathogenic single gene mutation. (7) There were 25 patients treated with total enteral nutrition. Among the 25 patients treated with thalidomide, 20 (80%) had clinical remission or partial remission. Among the 19 CD patients treated with infliximab (IFX), 14 had clinical remission at the 6(th) week of treatment, and the proportion of remission maintenance at the 30(th) week of treatment was 12/14. (8) The rate of clinical remission or partial remission was 64% (23/36) in the 0 -<2 years old group, 8/10 in the 2 -<6 years old group, 11/12 in the 6 -<10 years old group, and 83% (24/29) in the 10 -<18 years old group. Conclusions: The proportion of CD was higher than that of UC in this study. Infant onset inflammatory bowel disease was more likely to present with perianal lesions, and was usually associated with leukocytosis, thrombocytosis and anemia, and has high possibility of single gene mutation. IFX may be effective in treating CD.

Effect of age and parity on maternal diastolic function in middle trimester pregnant women with normal left ventricular ejection fraction and potential link of diastolic function to pre-eclampsia

Background

It has been suggested that maternal cardiac adaptations during pregnancy differ between nulliparous and multipara women and also vary according to the age. Impaired cardiac function precedes pre-eclampsia.

Purpose

To evaluate effect of age and parity on maternal cardiac diastolic function in middle trimester among pregnant women with normal left ventricular ejection fraction as well as correlation between impaired diastolic function and pre-eclampsia.

Methods

Pregnant women with singleton pregnancies carried from 13 weeks to 20 weeks and left ventricular ejection fraction (LVEF) ≥50% were identified. Diastolic function parameters were assessed using transthoracic echocardiography. Pre-eclampsia was identified from medical records.

Results

376 pregnant women were included (median age: 30 years; median gestational age: 14 weeks; 171 multiparous women). LVEF was 66%. Impaired cardiac diastolic function was seen in 7.8% of pregnant women &lt;35 years compared with 28.6% of those ≥35 years (p=0.000). ROC curve showed women with maternal age over 32 began to have a higher rate of impaired cardiac diastolic function (AUC=0.704, p=0.000, sensitivity=54.5%, specificity=75.3%). There was no difference in diastolic function indices between maternal women grouped by parity. After adjustment for confounders, maternal age can be independent effect factor of Em declined (P&lt;0.05). Em&lt;13cm/s was significantly associated with pre-eclampsia occurrence (HR 8.56; 95% CI: 3.40–21.57) after adjusting for the confounders.

Conclusion

Maternal age is an independent impact factor for diastolic function decline. There is no difference in cardiac diastolic function between nullipara and multipara. Pre-eclampsia occurrence is significantly higher in patients with diastolic function decline at mid-gestation. The utility of risk stratification using diastolic function at mid-gestation may improve the survival outcomes of pregnant women.

Association between Em and PE risk

Funding Acknowledgement

Type of funding source: None

The prokaryotic expression, polyclonal antibody preparation, and subcellular localization of the transmembrane protein NS2A of the duck Tembusu virus

Duck Tembusu virus (DTMUV) is a single-stranded, positive-sense RNA arbovirus, belonging to the genus Flavivirus, the family Flaviviridae. As a transmembrane protein, non-structural protein 2A (NS2A) plays an important role in virion assembly, replication complex and antagonizing host immune response. Since NS2A protein contains many hydrophobic amino acids, it is hard to gain the full-length protein of NS2A for prokaryotic expression. Therefore, to make a deep study, prokaryotic expression and polyclonal antibody preparation of truncated DTMUV NS2A was performed. The truncated NS2A gene (178-450 bp) was obtained, and sub-cloned into the prokaryotic vector pGEX-4T-1 (pGEX-4T-1-NS2A178-450bp). Subsequently, the recombinant GST-NS2A60-150aa protein was successfully expressed in E. coli BL21 (DE3) with the induction by 0.3 mmol/l isopropyl β-D-thiogalactoside (IPTG) for 6 h at 37°C. The GST-NS2A60-150aa protein was extracted from the gel. The BALB/c mice were immunized with the purified recombinant NS2A protein to prepare polyclonal antibodies against the truncated NS2A protein. The titer of the polyclonal antibodies, determined by ELISA analysis, was 1:128,000. The specificity of the polyclonal antibodies (mPAb-DTMUV-NS2A60-150aa) were verified by Western blot analysis. Furthermore, the indirect immunofluorescence (IFA) was performed to explore the subcellular localization of NS2A. NS2A protein was, in the transfected cells, located mainly around nucleus in the endoplasmatic reticulum. Taken together, our study provided a useful tool for the further exploration of the biological functions and molecular mechanism of DTMUV NS2A. Keywords: duck Tembusu virus; non-structural protein 2A; prokaryotic expression; polyclonal antibodies; subcellular location.

Associations between circulating bone-derived hormones lipocalin 2, osteocalcin, and glucose metabolism in acromegaly

PURPOSE

The aim was to examine changes in the bone-derived hormone lipocalin 2 (LCN2) levels in patients with active acromegaly and to investigate the potential roles of LCN2 and osteocalcin in glucose metabolism.

METHODS

We recruited 50 consecutive acromegalic patients. Of those, 39 patients with complete postoperative follow-up data were included. Thirty sex-, age-, and BMI-matched healthy individuals were recruited as normal controls. The pre- and postoperative serum LCN2 and osteocalcin levels were compared. The homeostasis model assessment insulin resistance (HOMA-IR) index and secretion [β-cell function (HOMA-β)] were calculated.

RESULTS

Compared with controls, acromegalic subjects had lower LCN2 levels (34.15 ± 9.95 vs 57.50 ± 29.75 ng/mL, P < 0.01) and higher osteocalcin levels (55.45 ± 34.02 vs 19.46 ± 6.69 ng/mL, P < 0.01). Acromegalic patients also had elevated HOMA-IR levels, and the HOMA-β and the area under the curve for insulin (AUC INS) levels were slightly but nonsignificantly increased. The serum levels of LCN2 significantly increased after surgery (37.03 ± 9.73 vs 45.15 ± 15.33 ng/mL, P < 0.05), and those of osteocalcin significantly decreased [43.51 (26.73-65.66) vs 24.79 (18.39-32.59) ng/mL, P < 0.01]. Total lean mass was the only positive predictor of LCN2, and elevated serum IGF-I was a positive predictor of osteocalcin. Low LCN2 and elevated serum osteocalcin levels were predictors of the AUC INS, and osteocalcin was a positive predictor of HOMA-β.

CONCLUSION

The bone-derived hormones, osteocalcin and LCN2 changed significantly in active acromegaly, were altered after treatment and served as predictors of β-cell function in acromegaly. This study shows that the bone could be involved in regulating glucose metabolism in acromegaly.

Highly Diastereoselective Synthesis of 2,2-Disubstituted Cyclopentane-1,3-diols via Stepwise Ketone Reduction Enabling Concise Chirality Construction

A series of 2,2-disubstituted trans,cis-cyclopentane-1,3-diols were synthesized in >99% dr through enzymatic reduction of enantiopure 2,2-disubstituted 3-hydroxycyclopentane-1-ones, which were prepared by highly stereoselective enzymatic reduction of the corresponding cyclodiketones. For 2-benzyl-2-methyl-3-oxocyclopentyl acetate, acetylation of the hydroxyl group significantly affected the reduction stereoselectivity, giving trans,cis-, trans,trans-, and cis,cis-2-benzyl-2-methyl-cyclopentane-1,3-diols in stereomerically pure form. This efficient and environmentally friendly method provides a practical approach to the synthesis of these chiral building blocks in single stereoisomeric form, demonstrating the power of biocatalysis in the concise chirality construction of complex chiral molecules.

2,3-Dihydroxybenzoic Acid Decarboxylase from Fusarium oxysporum: Crystal Structures and Substrate Recognition Mechanism

A 2,3-dihydroxybenzoic acid decarboxylase from Fusarium oxysporum (2,3-DHBD_Fo) has a relatively high catalytic efficiency for the decarboxylation of 2,3-dihydroxybenzoic acid (DHBA) and carboxylation of catechol, thus it has a different substrate spectrum from other benzoic acid decarboxylases. We have determined the structures of 2,3-DHBD_Fo in its apo form and complexes with catechol or 2,5-dihydroxybenzoic acid at 1.55, 1.97, and 2.45 Å resolution, respectively. The crystal structures of 2,3-DHBD_Fo show that the enzyme exists as a homotetramer, and each active center has a Zn²⁺ ion coordinated by E8, H167, D291 and three water molecules. This is different from 2,6-DHBD from Rhizobium sporomusa, in which the Zn²⁺ ion is also coordinated with H10. Surprisingly, mutation of A10 of 2,3-DHBD_Fo to His resulted in almost complete loss of the enzyme activity. Enzyme-substrate docking and site-directed mutation studies indicate that residue R233^Δ interacts with the 3-hydroxy group of 2,3-DHBA, and plays an important role in substrate recognition for this enzyme, thus revealing the molecular basis 2,3-dihydroxybenzoic acid decarboxylase.

Blastulation of a zygote to a hatched blastocyst without any clear cell division: an observational finding in a time-lapse system after in vitro fertilization

PURPOSE

To describe an interesting not previously described morphokinetic finding.

METHODS

Retrospective case report of a couple undergoing controlled ovarian stimulation (COS) followed by in vitro fertilization and blastocyst transfer.

RESULTS

We identified a unique finding of blastulation of a fertilized human zygote after conventional in vitro fertilization. The fertilized zygote did not show any clear cytokinesis until approximately 107 h post insemination, when it started dividing into a blastocyst. By 113 h post insemination, inner cell mass and trophectoderm cells could be clearly distinguished and the blastocyst was completely hatched by 136 h post insemination.

CONCLUSION

Time-lapse systems offer more detailed observations of embryonic development. Here, we report an atypical development of an embryo that was not described previously. We hope to become an insightful discussion among peers and incentive the publication of such findings in the future.

Genetic variants in the folate metabolic pathway genes predict cutaneous melanoma-specific survival

BACKGROUND

Folate metabolism plays an important role in DNA methylation and nucleic acid synthesis and thus may function as a regulatory factor in cancer development. Genome-wide association studies (GWASs) have identified some single-nucleotide polymorphisms (SNPs) associated with cutaneous melanoma-specific survival (CMSS), but no SNPs were found in genes involved in the folate metabolic pathway.

OBJECTIVES

To examine associations between SNPs in folate metabolic pathway genes and CMSS.

METHODS

We comprehensively evaluated 2645 (422 genotyped and 2223 imputed) common SNPs in folate metabolic pathway genes from a published GWAS of 858 patients from The University of Texas MD Anderson Cancer Center and performed the validation in another GWAS of 409 patients from the Nurses' Health Study and Health Professionals Follow-up Study, in which 95/858 (11·1%) and 48/409 (11·7%) patients died of cutaneous melanoma, respectively.

RESULTS

We identified two independent SNPs (MTHFD1 rs1950902 G>A and ALPL rs10917006 C>T) to be associated with CMSS in both datasets, and their meta-analysis yielded an allelic hazards ratio of 1·75 (95% confidence interval 1·32-2·32, P = 9·96 × 10^-5 ) and 2·05 (1·39-3·01, P = 2·84 × 10^-4 ), respectively. The genotype-phenotype correlation analyses provided additional support for the biological plausibility of these two variants' roles in tumour progression, suggesting that variation in SNP-related mRNA expression levels is likely to be the mechanism underlying the observed associations with CMSS.

CONCLUSIONS

Two possibly functional genetic variants, MTHFD1 rs1950902 and ALPL rs10917006, were likely to be independently or jointly associated with CMSS, which may add to personalized treatment in the future, once further validated. What is already known about this topic? Existing data show that survival rates vary among patients with melanoma with similar clinical characteristics; therefore, it is necessary to identify additional complementary biomarkers for melanoma-specific prognosis. A hypothesis-driven approach, by pooling the effects of single-nucleotide polymorphisms (SNPs) in a specific biological pathway as genetic risk scores, may provide a prognostic utility, and genetic variants of genes in folate metabolism have been reported to be associated with cancer risk. What does this study add? Two genetic variants in the folate metabolic pathway genes, MTHFD1 rs1950902 and ALPL rs10917006, are significantly associated with cutaneous melanoma-specific survival (CMSS). What is the translational message? The identification of genetic variants will make a risk-prediction model possible for CMSS. The SNPs in the folate metabolic pathway genes, once validated in larger studies, may be useful in the personalized management and treatment of patients with cutaneous melanoma.

Diversity and abundance of comammox bacteria in the sediments of an urban lake

AIMS

Although comammox have been discovered in a variety of ecosystems, there are few studies in urban lakes. This paper attempted to confirm whether this ammonia-oxidizing microbe exists in urban lakes and to determine the factors influencing its existence.

METHODS AND RESULTS

This study investigated the diversity and abundance of comammox bacteria in sediments of a typical urban lake in China, and their ecological relationship with other ammonia-oxidizing micro-organisms. The phylogenetic analysis indicated that comammox clade A existed in the sediment of Lake Donghu, and the comammox bacteria co-existed with ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing (anammox) bacteria in the sediment of this lake. The abundances of the ammonia monooxygenase subunit A (amoA) genes for comammox, AOA, AOB and anammox 16S rRNA were 2·43 × 10⁸ , 1·07 × 10⁸ , 3·24 × 10⁷ and 3·21 × 10¹¹ copies per gram dry sediment respectively. Moreover, the amoA gene abundance of comammox was positively correlated with that of AOA and AOB. The redundancy analysis showed that the abundance of the comammox amoA gene was negatively correlated with the concentration of main indicators for nitrogen status in both the sediment and the water column, indicating that eutrophication may inhibit the growth of comammox bacteria.

CONCLUSIONS

Comammox bacteria play an important ecological role in the nitrogen cycle of urban lake sediments.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results indicated comammox bacteria were widespread in urban lakes and eutrophication may inhibit their growth.