Pyran- and furanocoumarins are key representatives of tetrahydropyrans and tetrahydrofurans, respectively, exhibiting diverse physiological and medical bioactivities. However, the biosynthetic mechanisms for their core structures remain poorly understood. Here we combined multiomics analyses of biosynthetic enzymes in Peucedanum praeruptorum and in vitro functional verification and identified two types of key enzymes critical for pyran and furan ring biosynthesis in plants. These included three distinct P. praeruptorum prenyltransferases (PpPT1-3) responsible for the prenylation of the simple coumarin skeleton 7 into linear or angular precursors, and two novel CYP450 cyclases (PpDC and PpOC) crucial for the cyclization of the linear/angular precursors into either tetrahydropyran or tetrahydrofuran scaffolds. Biochemical analyses of cyclases indicated that acid/base-assisted epoxide ring opening contributed to the enzyme-catalyzed tetrahydropyran and tetrahydrofuran ring refactoring. The possible acid/base-assisted catalytic mechanisms of the identified cyclases were theoretically investigated and assessed using site-specific mutagenesis. We identified two possible acidic amino acids Glu303 in PpDC and Asp301 in PpOC as vital in the catalytic process. This study provides new enzymatic tools in the epoxide formation/epoxide-opening mediated cascade reaction and exemplifies how plants become chemically diverse in terms of enzyme function and catalytic process.

Objective:To investigate the application of three-dimensional image reconstruction combined with problem-based learning (PBL) in the teaching of physicians receiving continuing education in thoracic surgery.Methods:A total of 68 physicians who received continuing education in Department of Thoracic Surgery in our hospital were selected as research subjects, and they were divided into control group and observation group using a random number table, with 34 physicians in each group. The physicians in the control group received traditional teaching, while those in the observation group received three-dimensional image reconstruction combined with PBL teaching. A questionnaire survey, theoretical assessment, and assessment of practical skills were performed to evaluate the effect of teaching. SPSS 22.0 was used to perform the t-test. Results:Compared with the control group, the observation group had significantly higher degrees of satisfaction with each item of the questionnaire survey ( P<0.05). Compared with the control group, the observation group had significantly higher scores of theoretical assessment [(94.07±6.03) vs. (86.34±5.46), P<0.001] and the assessment of practical skills [(95.20±5.48) vs. (84.71±6.14), P<0.001]. Conclusion:The application of three-dimensional image reconstruction combined with PBL teaching can help to improve the comprehensive ability of physicians receiving continuing education.

Objective:To investigate the effect of a breathing pattern intervention (RPI) on the oral feeding of pre-term infants with suck-swallow-breath (SSwB) coordination disorder.Methods:Sixty pre-term infants with SSwB coordination disorder were divided into an observation group ( n=30) and a control group ( n=30) using a random number table. Both groups were given routine feeding training, including oral exercise intervention, non-nutritive sucking training, and swallowing induction training during nursing, while the observation group was additionally provided with 15 minutes of breathing pattern training once a day, including breathing pattern observation, resistive breathing training prior to eating and passive breathing pattern intervention during eating. Before and after the 7-day intervention, the Pre-term Infant Oral Feeding Readiness Assessment (PIOFRA) was used to evaluate each subject′s oral feeding ability. Rate of transfer (RT), proficiency (PRO), minimum oxygen partial pressure (SaO 2) and SaO 2 fluctuations were also recorded during the feeding process. Results:After 1 week of the intervention, significant improvement was observed in both groups. In the observation group the average RT (2.76±0.36ml/min), PRO, minimum SaO 2, the number of SaO 2 fluctuations, and PIOFRA score (33.28±0.58) were all significantly better than the control group′s averages. Conclusion:Breathing pattern intervention based on routine feeding training can enhance breathing coordination during swallowing and ultimately improve the oral feeding of pre-term infants with SSwB coordination disorders in a relatively short period of time.

Objective:To understand the current situation of children's fluorosis in the coal-burning-borne endemic fluorosis areas (abbreviated as coal-burning fluorosis) in Suojia Miao, Yi and Hui Township (Suojia Township for short) in Liuzhi Tequ, Guizhou Province, and to provide scientific basis for formulating prevention and control strategies and measures.Methods:In 2019, the cluster sampling method was adopted to select children aged 8-12 years old from 6 primary schools in Suojia Township, Liuzhi Tequ, Guizhou Province to conduct a questionnaire survey to collect basic information, and perform dental fluorosis examination and indexing in accordance with the "Diagnosis of Dental Fluorosis" standards. Immediate urine samples were collected from children in April and October, and urinary fluoride content was determined by ion selective electrode method.Results:A total of 1 381 children aged 8-12 years old were investigated, aged (9.84 ± 1.38) years old, including 679 boys and 702 girls. A total of 625 children with dental fluorosis were detected, and the detection rate was 45.26%; the dental fluorosis index was 1.00, and the prevalence intensity was moderate; the main score of dental fluorosis was extremely mild, accounting for 37.00% (511/1 381). The detection rates of dental fluorosis in children aged 8 to 12 years old were 35.10% (106/302), 35.83% (115/321), 47.96% (129/269), 55.23% (153/277), and 57.55% (122/212), respectively; the difference between different ages was statistically significant (χ 2 = 48.949, P < 0.01), and the detection rate of dental fluorosis in children increased with age(χ 2trend = 45.254, P < 0.01).The detection rates of dental fluorosis in boys and girls were 43.59% (296/679) and 46.87% (329/702), respectively, and there was no significant difference between different genders (χ 2 = 1.492, P > 0.05). In April and October, 123 and 107 urine samples of children aged 8-12 years old were tested. The geometric mean of urinary fluoride was 1.55 and 0.47 mg/L, respectively. The urinary fluoride level in April was higher than the normal range (< 1.40 mg/L). Conclusions:Suojia Township in Liuzhi Tequ of Guizhou Province is still a fluorosis area, and there is a big difference in urinary fluorine level in different months, which indicates that the residents in this area may have intermittent high fluorine intake, and prevention and control of endemic fluorosis should be further strengthened.

Objective:To investigate the role of alloreactive T cell in clonal deletion and regulatory T cells ( Treg) in transplant tolerance.Methods:F1 mice were bred by crossing female BALB/c mice and male C57BL/6 mice.Within 24 h,newborn C57BL/6 mice were inoculated with F1 spleen cells via the orbital branch of the anterior facial vein.Six weeks later,the mice were subjected to F1 skin grafting to evaluate their tolerance.Proliferation,flow cytometry and adoptive transfer assay were used to analyze clonal deletion of alloreactive T cells and the expression of CD4+Foxp3+T cells in neonatal treated mice.Results: Newborn C57BL/6 mice injected with F1 splenic cells could induce transplantation tolerance,the level of tolerance was associated with the dose of splenic cells.3×107 splenic cells from F1 mice could induce long-term skin graft acceptance in C57BL/6 mice ,1×107splenic cells significantly prolonged the survival of F1 skin grafts,but the grafts completely rejected within 50 days.The mixed lymphocyte reaction ( MLR) experiment in vivo showed that alloreactive T cell in long-term tolerant mice was deleted completely,but a certain amount of reactive T cells existed in the low-dose group mice.Flow cytometry ( FCM) analysis showed that the expression of CD4+Foxp3+T cell in the high-dose group and low-dose group mice had no obvious difference compared with the naive mice.When alloreactive T-cells were injected into tolerant mice,the skin graft rejection was observed,and Treg cells upregulated in graft-rejected mice.Conclusion:The degree of transplantation tolerance depended on the clonal deletion of alloreactive T cells,instead of on the expression of CD4+Foxp3+Treg cells.CD4+Foxp3+regulatory T cells upregulated in graft rejected mice,which may be served as a negative feedback mechanism to control the intensity of rejection.

Objective To explore the significance and value of the anti-nucleosome antibodies(AnuA)in the diagnosis of system-ic lupus erythematosus(SLE).Methods The serum AnuA was detected in 177 patients with SLE,138 patients with other rheumat-ic diseases and 56 healthy controls by Western blot.The clinical manifestations,autoantibodies and other test results were recorded in the SLE patients.The AnuA and other autoantibodies were analyzed.Results The positive rate of AnuA in the SLE group was significantly higher than that in the disease control group,AnuA was negative in the healthy control group;the sensitivity of AnuA in the SLE group was 48.6% and the specificity was 95.3%;the sensitivity of AnuA was significantly higher than that of the anti-ds-DNA antibodies and anti-Sm antibodies,the difference had statistical significance (P <0.05).The specificity of AnuA was higher than that of ANA and histone (P <0.05 ).The sensitivity of joint detection of AnuA,anti-ds-DNA and anti-Sm antibodies was 89.8%,which was significantly higher than that of a single index detection.The positive rate of AnuA in the active period of SLE was significantly higher than that of the non-active period,moreover higher than that of the ds-DNA antibodies (P <0.05).Conclu-sion AnuA might participate in the pathogenesis of SLE.The joint detection of autoantibodies including AnuA,etc.has importance significance in the diagnosis,condition judgment and curative efficacy evaluation of SLE.

Objective To investigate the relationship between aquaporin-1, -2, -3, -4 mRNA (AQP1-4) and renal parenchyma thickness in congenital hydronephrotic kidney in children. Methods The expressions of aquaporin 1, -2, -3, and -4 mRNA in hydronephrotic kidney of 37 children (aged 60.3±48.8 months) were evaluated with congenital hydronephrosis and control kidney of 6 children (aged 62.7±17.1 months) by using semi-quantitative reverse transcriptase polymerase chain reaction technique. Hydronephrotic kidney parenchyma thickness was measured by B-Ultrasound preoperative-ly and verified at operation. The relations of aquaporin 1, -2, -3, and -4 mRNA to the hydronephrotic kidney parenchyma thickness were analyzed by correlation analysis. Results The aquaporin 1 ,-2,-3, and -4/beta-actin ratio in the hydronephrotic kidney and normal kidney were 0.39±0.22 vs 0.90± 0.10, 0.42±0.20 vs 0.92±0.09, 0.525±0.22 vs 0.98±0.12, 0.30±0.18 vs 0.74±0.21 respec-tively, and the differences were significant (P<0.01). Hydronephrotic kidney parenchyma thickness measured by D-Ultrasound was 5.01±2.38 mm, which was identical with those measured at opera-tion. Significant correlation was found between the levels of aquaporin 1,-2,-3, and -4 mRNA and hydronephrotic kidney parenchyma thickness (r=0.773, 0.772, 0.557, 0.625, respectively; P< 0.01). Conclusions Significant correlation exists between decreased expressions of aquaporin 1 ,-2, -3, and -4 mRNA and atrophic change of renal parenchyma. This result may provide evidence to ex-plain the mechanism why the thinner renal parenchyma thickness, the weaker renal concentration and dilution function.

Objective To investigate the clinical characteristics of hypertrophic cardiomyopathy (HCM) in the elderly. Methods The clinical characters of HCM in 70 elderly patients were retrospectively analysed. Results Among the 196 identified HCM patients, 70 were elders. Out of them, 7 patients(10.0%) were suspected as HCM according to the clinical symptoms, 29 patients (41.4%)were suspected as other cardiac diseases, 34 (48.3%) were diagnosed HCM due to other reasons. Among the 70 patients, 12 patients(17.1%) had history of cerebrovascular diseases, 54 (77.1%) manifested symptoms after 45 years of age and 4 (5.7%) showed no obvious symptoms. Among them, 18 patients were examined by UCG for two times and HCM was diagnosed at the second time. Conclusions HCM in the elderly is not an uncommon disease. The onset of cardiac symptoms is relatively late in the elderly HCM and frequently misdiagnosed; cerebrovascular diseases are commonly seen in elderly HCM patients.

OBJECTIVETo evaluate the feasibility, safety and diagnostic accuracy of pharmacologic stress of (99m)Technetium-MIBI single-photon emission computed tomography (SPECT) with intravenous adenosine triphosphate (ATP) in patients with suspected coronary artery disease.

METHODSThe study group included 263 patients who were suspected of having coronary artery disease. All patients underwent (99m)Tc-MIBI myocardial perfusion imaging with ATP infusion (0.16 mg/kg body weight per min for 5 min). 20 mCi of (99m)Tc-MIBI were injected 3 minutes after the start of ATP infusion. Myocardial SPECT images were obtained 60 minutes later. Then, two days later, 20 mCi of (99m)Tc-MIBI were administered at rest and myocardial SPECT was repeated. 51 patients also underwent coronary angiography within two weeks for evaluation of sensitivity and specificity of ATP-myocardial perfusion imaging in detection of coronary artery disease. The occurrence of cardiac and non-cardiac adverse effects was carefully monitored during and after intravenous ATP infusion.

RESULTSThe ATP infusion protocol was completed in all patients. Although 59% of the patients had various kinds of adverse effects, most of them were mild. No patient required aminophyline. The most severe adverse effect was second degree type II atria-ventricular block (4/263), but all events were transient. The sensitivity and specificity of ATP-myocardial perfusion imaging were 97% and 82%, respectively.

CONCLUSIONSIt is shown that (99m)Technetium-MIBI SPECT with intravenous ATP is a safe and feasible technique for detecting coronary artery disease in patients unable to perform the exercise test.

Adenosine Triphosphate ; adverse effects ; Adult ; Aged ; Aged, 80 and over ; Coronary Angiography ; Coronary Disease ; diagnosis ; Female ; Heart ; diagnostic imaging ; Humans ; Male ; Middle Aged ; Sensitivity and Specificity ; Technetium Tc 99m Sestamibi ; Tomography, Emission-Computed, Single-Photon

Objective To study the association between the plasma homocysteine level and coronary artery disease(CAD), and the methylenetetrahydrofolate reductase (MTHFR) A1298C polymorphism, the methionine synthase (MS) A2756G polymorphism and their associations to the plasma homocysteine level and CAD in the elderly . Methods One hundred and twenty-nine elderly patients with CAD documented by coronary angiogram and 48 elderly patients with normal coronary angiographic results were included in this study. Plasma homocysteine level were measured by fluorescence polarization immunoassay (FPIA) method and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to analyse the MTHFR A1298C and MS A2756G genotypes. Results The plasma homocysteine level was significantly higher in CAD group than that in the control group〔(16.2?8.6) ?mol/L vs (12.7?5.0) ?mol/L,P0.05);the prevalence of MTHFR 1298CC homozygous in the CAD patients was significantly less than that in the control group (3.1% vs 14.6%, P