Significance of QRS scoring system in left ventricular function recovery after acute myocardial infarction.

AIMS: The Selvester scoring system has been derived from ECG parameters for estimating infarct size. However, there is still a lack of evidence for Selvester score as an alternative to cardiac magnetic resonance (CMR) myocardial injury makers for risk stratification and prediction of left ventricular function (LVF) recovery among patients with ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS: This multicentre observational study enrolled 328 STEMI patients (88.4% men, 57.3 ± 10.6 years of age) undergoing CMR examination 1 week post-reperfusion therapy. Patients with baseline left ventricular ejection fraction (LVEF) < 50% underwent a follow-up CMR 6 months later, categorized into baseline normal LVF (ejection fraction [EF] ≥ 50% at baseline, n = 155); recovered LVF (EF < 50% at baseline and ≥50% after 6 months, n = 69); and reduced LVF (EF < 50% at baseline and after 6 months, n = 104). The median follow-up was 4 (3-4) years for all patients, with 61 patients experiencing major adverse cardiovascular event (MACEs). Patients with reduced LVF had a higher risk of MACEs than those with baseline normal LVF (P = 0.01), while the recovered LVF group had no significant difference (P > 0.05). A Selvester score >10 doubled the risk of MACEs in patients with systolic dysfunction (1.91 [1.02 to 3.58], P = 0.04). Additionally, Selvester score, baseline LVEF, transmural infarction, and peak CK-MB were independent predictors of recovered LVF, with Selvester score providing incremental predictive value to peak CK-MB in predicting recovered LVF (∆AUC = 0.07, P < 0.05). CONCLUSIONS: The Selvester score improves risk stratification among STEMI patients beyond LVEF and provide independent and incremental information to clinical parameters in predicting recovered LVF.

Health technology assessment in traditional and complementary medicine: a scoping review of international activity and examples of acupuncture.

BACKGROUND: Traditional therapies are crucial in maintaining and improving human well-being. China's healthcare policymakers are attempting to use health technology assessment (HTA) as a decision-making supportive tool. The value assessment framework for Chinese patent medicine (CPM) has been developed and is being adopted and validated widely by research institutions. Subsequently, the healthcare decision-makers particularly hanker for the value framework of traditional non-pharmacological therapies. METHODS: To construct a practical value framework for traditional non-pharmacological therapies, a scoping review methodology was adopted to identify the evaluation domains and obstacles. A search, screening, and analysis process was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Evidence was retrieved from scientific databases and HTA agencies' websites. RESULTS: The search strategy identified 5 guidelines records and 17 acupuncture HTA reports. By synthesizing the valuable reports of CPM and acupuncture evaluation in representative countries, this study found that Mainland China was promoting the comprehensive value assessment of CPM, whereas the United Kingdom, Singapore, Canada, the United States, and Malaysia had carried out the HTA evaluation of acupuncture for various conditions among which chronic pain was the most common. UK and Singapore applied the HTA results to support acupuncture reimbursement decisions. Three domains, including safety, effectiveness, and economy, were commonly adopted. The identified biggest challenge of evaluating traditional non-pharmacological therapies is the scarce high-quality clinical evidence. CONCLUSIONS: This study identified value domains and issues of traditional therapies, and pointed out future research implications, to promote the development value framework of traditional therapies.

[Effect of 28-day administration of Psoraleae Fructus water extract on early liver injury in rats].

This study aims to investigate the hepatotoxicity of Psoraleae Fructus water extract and the underlying mechanism in rats. Forty-eight rats were randomly assigned into four groups: a blank group and low-(BZGL, 6.25 g·kg~(-1)), medium-(BGZM, 12.5 g·kg~(-1)), and high-dose(BGZH, 25 g·kg~(-1)) Psoraleae Fructus water extract groups. The rats were treated for 28 days, and toxicity and mortality were observed daily. After 28 days, the rats were sacrificed, and the body weight, liver index, and liver-to-brain ratio were calculated. The morphological changes in the liver tissue were observed, and the serum levels of related biochemical indicators were measured. The results showed that compared with the blank group, Psoraleae Fructus water extracts of different doses decreased the body weight, increased the liver index and liver-to-brain ratio, and caused liver hypertrophy and pathological changes. Pathological examination revealed that the rats in Psoraleae Fructus water extract groups had bile duct hyperplasia, inflammatory cell infiltration, and liver cell fibrosis. Compared with the blank group, BGZL elevated the levels of alanine transaminase(ALT), α-glutathione S-transferase(α-GST), and total bile acid(TBA)(P<0.05), and BGZM and BGZH elevated the levels of ALT, TBA, α-GST, γ-glutamyl transferase(γ-GT), purine nucleoside phosphorylase(PNP), ornithine carbamoyltransferase(OCT), and arginase(ArgI)(P<0.05). Compared with the blank group, Psoraleae Fructus water extracts of different doses down-regulated the mRNA and protein levels of bile salt export pump(BSEP) and farnesoid X receptor(FXR) and up-regulated the mRNA and protein levels of tumor necrosis factor-α(TNF-α), nuclear factor kappaB(NF-κB), and cholesterol 7 alpha-hydroxylase(CYP7A1)(P<0.05). The results suggested that Psoraleae Fructus water extract caused toxicity in rats, showing a dose-toxicity relationship. Psoraleae Fructus water extract may cause liver damage, which may be due to its effect on liver bile acid secretion and induction of inflammation.

Non-Contrast Cine Cardiac Magnetic Resonance Derived-Radiomics for the Prediction of Left Ventricular Adverse Remodeling in Patients With ST-Segment Elevation Myocardial Infarction.

OBJECTIVE: To investigate the predictive value of radiomics features based on cardiac magnetic resonance (CMR) cine images for left ventricular adverse remodeling (LVAR) after acute ST-segment elevation myocardial infarction (STEMI). MATERIALS AND METHODS: We conducted a retrospective, single-center, cohort study involving 244 patients (random-split into 170 and 74 for training and testing, respectively) having an acute STEMI (88.5% males, 57.0 ± 10.3 years of age) who underwent CMR examination at one week and six months after percutaneous coronary intervention. LVAR was defined as a 20% increase in left ventricular end-diastolic volume 6 months after acute STEMI. Radiomics features were extracted from the one-week CMR cine images using the least absolute shrinkage and selection operator regression (LASSO) analysis. The predictive performance of the selected features was evaluated using receiver operating characteristic curve analysis and the area under the curve (AUC). RESULTS: Nine radiomics features with non-zero coefficients were included in the LASSO regression of the radiomics score (RAD score). Infarct size (odds ratio [OR]: 1.04 (1.00-1.07); P = 0.031) and RAD score (OR: 3.43 (2.34-5.28); P < 0.001) were independent predictors of LVAR. The RAD score predicted LVAR, with an AUC (95% confidence interval [CI]) of 0.82 (0.75-0.89) in the training set and 0.75 (0.62-0.89) in the testing set. Combining the RAD score with infarct size yielded favorable performance in predicting LVAR, with an AUC of 0.84 (0.72-0.95). Moreover, the addition of the RAD score to the left ventricular ejection fraction (LVEF) significantly increased the AUC from 0.68 (0.52-0.84) to 0.82 (0.70-0.93) (P = 0.018), which was also comparable to the prediction provided by the combined microvascular obstruction, infarct size, and LVEF with an AUC of 0.79 (0.65-0.94) (P = 0.727). CONCLUSION: Radiomics analysis using non-contrast cine CMR can predict LVAR after STEMI independently and incrementally to LVEF and may provide an alternative to traditional CMR parameters.

The effect of JuanBiQiangGu granules in combination with methotrexate on joint inflammation in rheumatoid arthritis: a randomized controlled trial.

Background: Rheumatoid arthritis (RA) joint inflammation severely affects joint function and quality of life in patients and leads to joint deformities and limb disability. The non-steroidal anti-inflammatory drugs used in the treatment of RA do not fully control the progression of joint inflammation and bone destruction and have notable adverse reactions. Traditional Chinese medicine formula JuanBiQiangGu Granules (JBQG) are commonly used for the treatment of RA inflammation and delay of bone destruction, but has not been evaluated through high-quality clinical studies. There is a pressing need for well-designed, randomized, parallel, controlled clinical studies to evaluate the exact effect of JBQG on RA joint inflammation and improvement of patient quality of life. Methods: This is a randomized, parallel, controlled clinical study in which 144 patients with rheumatoid arthritis who met the inclusion criteria were randomly assigned to 2 groups in a 1:1 ratio. The JBQG group received methotrexate 7.5 mg qw and JBQG granules 8 mg tid, while the MTX group received methotrexate 7.5 mg qw. The endpoint was 12 weeks after treatment. Relevant indices at baseline, 4 weeks, 8 weeks, and 12 weeks after treatment were observed and recorded, and DAS28-ESR, HAQ-DI, and Sharp scores were recorded for each patient. Blood samples were collected to test for CRP, ESR, TNF-α, IL-1ß, IL-6, IL-17, and INF-γ, and adverse reactions and liver and kidney function (AST, ALT, Cr, BUN) were recorded for safety assessment. After 12 weeks of treatment, the effect of JBQG granules on disease activity, improvement in bone damage, and patient quality of life scores and safety in RA patients were evaluated. Results: A total of 144 subjects completed treatment (71 in the JBQG group and 73 in the MTX group) and were included in the analysis. At baseline, there were no significant differences between the groups in terms of the observed indicators (p > 0.05). After treatment, 76.06% of patients in the JBQG group had DAS28-ESR levels below or equal to Low, including 45.07% in Remission and 5.63% in High, compared to 53.1% in the MTX group below or equal to Low, 12.33% in Remission, and 17.81% in High. CRP was significantly reduced (8.54 ± 5.87 vs. 11.86 ± 7.92, p < 0.05, p = 0.005), ESR was significantly reduced (15.1 ± 6.11 vs. 21.96 ± 9.19, p < 0.0001), TNF-α was significantly reduced (1.44 ± 0.83 vs. 1.85 ± 1.07, p < 0.05, p = 0.011), IL-17 was significantly reduced (0.53 ± 0.33 vs. 0.71 ± 0.38, p < 0.05, p = 0.004), and INF-γ was significantly reduced (3.2 ± 1.51 vs. 3.89 ± 1.77, p < 0.05, p = 0.014). The median (IQR) OPG in the JBQG group was 2.54 (2.21-3.01), significantly higher than in the MTX group 2.06 (1.81-2.32), p < 0.0001), and the median (IQR) ß-CTX in the JBQG group was 0.4 (0.32-0.43), significantly lower than in the MTX group 0.55 (0.47-0.67), p < 0.0001). The median (IQR) VSA scores were 2 (1-3), a decrease from 3 (2-4) in the MTX group (p < 0.0001). The median (IQR) Sharp scores were 1 (1-2), a decrease from 2 (1-2) in the MTX group, but the difference was not statistically significant (p > 0.05, p = 0.28). The median (IQR) HAQ-DI scores were 11 (8-16), significantly lower than in the MTX group 26 (16-30) (p < 0.0001). The median (IQR) AST in the JBQG group was 16 (12-20), with a significant difference compared to the MTX group 19 (13-25) (p < 0.01, p = 0.004); the median (IQR) ALT in the JBQG group was 14 (10-18), with a significant difference compared to the MTX group 16 (11-22.5) (p < 0.05, p = 0.015). There were no statistically significant differences in Cr or BUN (p > 0.05). Conclusion: JuanBiQiangGu Granules can be used to treat patients with rheumatoid arthritis, alleviate joint inflammation, reduce the incidence of adverse reactions to methotrexate, and has good safety. Clinical Trial Registration: http://www.chinadrugtrials.org.cn/index.html; identifier: ChiCTR2100046373.

Early Trimetazidine Therapy in Patients Undergoing Primary Percutaneous Coronary Intervention for ST Segment Elevation Myocardial Infarction Reduces Myocardial Infarction Size.

PURPOSE: Trimetazidine, a metabolic agent with anti-ischemic effects, was reported to reduce reperfusion injury in animal models. In this randomized double-blind placebo-controlled trial, we investigated the effects of trimetazidine on the reduction of infarction size in patients undergoing revascularization for ST segment elevation myocardial infarction (STEMI). METHODS: Patients with STEMI randomly received trimetazidine (n = 87) or placebo (n = 86) before primary percutaneous coronary intervention (PCI), and subsequently received oral trimetazidine or placebo for 12 months after reperfusion. The predefined primary endpoint was infarction size on cardiac magnetic resonance (CMR) performed at 7 days after primary PCI. The trial was registered on www. CLINICALTRIALS: gov (registration number: NCT02826616). RESULTS: The clinical characteristics of the patients in both groups were well-matched at baseline. At 7 days after primary PCI, the percentage and absolute infarction size in the trimetazidine group were significantly smaller than those in the control group (22% ± 12% [n = 74] vs. 27% ± 13% [n = 74], p = 0.011 and 28 ± 18 g [n = 74] vs. 35 ± 19 g [n = 74], p = 0.022, respectively), and the incidence of myocardial microvascular obstruction (MVO) measured by CMR was significantly reduced in the trimetazidine group (29.7% [22/74] vs. 52.7% [39/74], p = 0.005). The myocardial salvage index (MSI) measured by CMR was significantly higher in the trimetazidine group (48% ± 20% vs. 39% ± 20%, p = 0.008). The incidence of readmission due to aggravated heart failure did not differ significantly between the trimetazidine group and the control group (8.0% vs. 14.0%, p = 0.234). CONCLUSIONS: In patients with STEMI undergoing primary PCI, early trimetazidine before reperfusion reduced myocardial infarction size and MVO, and improved MSI.

Machine learning-based prediction of infarct size in patients with ST-segment elevation myocardial infarction: A multi-center study.

BACKGROUND: Cardiac magnetic resonance imaging (CMR) is the gold standard for measuring infarct size (IS). However, this method is expensive and requires a specially trained technologist to administer. We therefore sought to quantify the IS using machine learning (ML) based analysis on clinical features, which is a convenient and cost-effective alternative to CMR. METHODS AND RESULTS: We included 315 STEMI patients with CMR examined one week after morbidity in final analysis. After feature selection by XGBoost on fifty-six clinical features, we used five ML algorithms (random forest (RF), light gradient boosting decision machine, deep forest, deep neural network, and stacking) to predict IS with 26 (selected by XGBoost with information gain greater than average level of 56 features) and the top 10 features, during which 5-fold cross-validation were used to train and optimize models. We then evaluated the value of actual and ML-IS for the prediction of adverse remodeling. Our finding indicates that MLs outperform the linear regression in predicting IS. Specifically, the RF with five predictors identified by the exhaustive method performed better than linear regression (LR) with 10 indicators (R2 of RF: 0.8; LR: 0). The finding also shows that both actual and ML-IS were independently associated with adverse remodeling. ML-IS ≥ 21% was associated with a twofold increase in the risk of LV remodeling (P < 0.01) compared with patients with reference IS (1st tertile). CONCLUSION: ML-based methods can predict IS with widely available clinical features, which provide a proof-of-concept tool to quantitatively assess acute phase IS.

Effects of Nicorandil Administration on Infarct Size in Patients With ST-Segment-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention: The CHANGE Trial.

Background Nicorandil was reported to improve microvascular dysfunction and reduce reperfusion injury when administered before primary percutaneous coronary intervention. In this multicenter, prospective, randomized, double-blind clinical trial (CHANGE [Effects of Nicorandil Administration on Infarct Size in Patients With ST-Segment-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention]), we investigated the effects of nicorandil administration on infarct size in patients with ST-segment-elevation myocardial infarction treated with primary percutaneous coronary intervention. Methods and Results A total of 238 patients with ST-segment-elevation myocardial infarction were randomized to receive intravenous nicorandil (n=120) or placebo (n=118) before reperfusion. Patients in the nicorandil group received a 6-mg intravenous bolus of nicorandil followed by continuous infusion at a rate of 6 mg/h. Patients in the placebo group received the same dose of placebo. The predefined primary end point was infarct size on cardiac magnetic resonance (CMR) imaging performed at 5 to 7 days and 6 months after reperfusion. CMR imaging was performed in 201 patients (84%). Infarct size on CMR imaging at 5 to 7 days after reperfusion was significantly smaller in the nicorandil group compared with the placebo (control) group (26.5±17.1 g versus 32.4±19.3 g; P=0.022), and the effect remained significant on long-term CMR imaging at 6 months after reperfusion (19.5±14.4 g versus 25.7±15.4 g; P=0.008). The incidence of no-reflow/slow-flow phenomenon during primary percutaneous coronary intervention was much lower in the nicorandil group (9.2% [11/120] versus 26.3% [31/118]; P=0.001), and thus, complete ST-segment resolution was more frequently observed in the nicorandil group (90.8% [109/120] versus 78.0% [92/118]; P=0.006). Left ventricular ejection fraction on CMR imaging was significantly higher in the nicorandil group than in the placebo group at both 5 to 7 days (47.0±10.2% versus 43.3±10.0%; P=0.011) and 6 months (50.1±9.7% versus 46.4±8.5%; P=0.009) after reperfusion. Conclusions In the present trial, administration of nicorandil before primary percutaneous coronary intervention led to improved myocardial perfusion grade, increased left ventricular ejection fraction, and reduced myocardial infarct size in patients with ST-segment-elevation myocardial infarction. Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT03445728.

Altered brain activity in end-stage knee osteoarthritis revealed by resting-state functional magnetic resonance imaging.

INTRODUCTION: Knee osteoarthritis (KOA) is characterized by a degenerative change of knee cartilage and secondary bone hyperplasia, resulting in pain, stiffness, and abnormal walking gait. Long-term chronic pain causes considerable cortical plasticity alternations in patients. However, the brain structural and functional alterations associated with the pathological changes in knee joints of end-stage KOA patients remain unclear. This study aimed to analyze the structural and functional connectivity alterations in end-stage KOA to comprehensively understand the main brain-associated mechanisms underlying its development and progression. METHODS: In this study, 37 patients with KOA and 37 demographically matched healthy controls (HCs) were enrolled. Alternations in gray matter (GM) volume in patients with KOA were determined using voxel-based morphometry. The region with the largest GM volume alteration was selected as the region of interest to calculate the voxel-wise resting-state functional connectivity (rs-FC) in the two groups. Pearson's correlation coefficient was used to analyze the correlation between clinical measures and GM volume alternations in patients with KOA. RESULTS: Compared with HCs, patients with KOAs exhibited significantly decreased GM volumes in the left middle temporal gyrus (left-MTG) and the left inferior temporal gyrus. Results of the voxel-wise rs-FC analysis revealed that compared with HCs, patients with KOA had decreased left-MTG rs-FC to the right dorsolateral superior frontal gyrus, left middle frontal gyrus, and left medial superior frontal gyrus. GM volume in the left-MTG was negatively correlated with the Western Ontario and McMaster Universities Arthritis Index in patients with KOA (r = -0.393, p = .016). CONCLUSION: Structural remodeling and functional connectivity alterations may be one of the central brain mechanisms associated with end-stage KOA.

Discovery of potent epidermal growth factor receptor (EGFR) degraders by proteolysis targeting chimera (PROTAC).

Epidermal growth factor receptor (EGFR), a member of the HER family, is closely related to the development of multiple cancers. Herein, we report the discovery of small molecule EGFR degraders based on the proteolysis targeting chimera (PROTAC) strategy. In the present study, 13 EGFR degraders containing pyrido[3,4-d] pyrimidine moiety were designed and synthesized. Promising PROTACs 2 and 10 induced degradation of EGFR in HCC827 cells with the DC50 values of 45.2 and 34.8 nM, respectively. Cellular protein-controlling machinery ubiquitin proteasome system (UPS) was involved in the degradation process. Furthermore, the degraders 2 and 10 could significantly induce the apoptosis of HCC827 cells and arrest the cells in G1 phase. These findings demonstrated that compounds 2 and 10 could serve as effective EGFRdel19-targeting degraders in HCC827 cells. v.

Genetic Diversity-Area Relationships across Bird Species.

The genetic diversity-area relationship (GAR), compared with the extensively explored species-area relationship (SAR), remains poorly recognized despite the importance of understanding it for the development and application of biodiversity theory. It has been hypothesized that maintaining genetic diversity within a population is mechanistically similar to maintaining species diversity within a community, implying that GAR trajectories should behave mathematically as SAR ones. Here we test this prediction by fitting microsatellite heterozygosity and allelic richness in relation to distribution range size across bird species against eight well-known SAR models. The Monod model best described the data on resident and migratory species combined and especially the data on resident species only, showing that with increasing range size, genetic diversity across species rapidly increased up to a certain level and then tended toward an asymptote. None of the candidate models provided an adequate fit for the data on migratory species, likely because their breeding range size mostly is large in that a GAR curve has become flat. Our work takes the first step toward formulating GARs and applying them to predicting the effect of habitat fragmentation on genetic diversity.

Cost-effectiveness of daclatasvir plus asunaprevir for chronic hepatitis C genotype 1b treatment-naïve patients in China.

BACKGROUND: Hepatitis C is the second fastest growing infectious disease in China. The standard-of-care for chronic hepatitis C in China is Pegylated interferon plus ribavirin (PR), which is associated with tolerability and efficacy issues. An interferon- and ribavirin-free, all-oral regimen comprising daclatasvir (DCV) and asunaprevir (ASV), which displays higher efficacy and tolerability, has recently been approved in China. OBJECTIVES: This study is to estimate the cost-effectiveness of DCV+ASV (24 weeks) for chronic hepatitis C genotype 1b treatment-naïve patients compared with PR regimen (48 weeks) in China. METHODS: A cohort-based Markov model was developed from Chinese payer perspective to project the lifetime outcomes of treating 10,000 patients with an average age of 44.5 with two hypothetical regimens, DCV+ASV and PR. Chinese-specific health state costs and efficacy data were used. The annual discount rate was 5%. Base-case analysis and sensitivity analysis were conducted. RESULTS: For HCV Genotype 1b treatment-naïve patients, DCV+ASV proved to be dominant over PR, with a cost saving of ¥33,480(5,096 USD) and gains in QALYs and life years of 1.29 and 0.85, respectively. The lifetime risk of compensated cirrhosis, decompensated cirrhosis, hepatocellular carcinoma and liver-related death was greatly reduced with DCV+ASV. Univariate sensitivity analysis demonstrated that key influencers were the discount rate, time horizon, initial disease severity and sustained virological response rate of DCV+ASV, with all scenarios resulting in additional benefit. Probabilistic sensitivity analysis demonstrated that DCV+ASV has a high likelihood (100%) of being cost-effective. CONCLUSION: DCV+ASV is not only an effective and well-tolerated regimen to treat chronic HCV genotype 1b infection treatment-naïve patients, but also is more cost-effective than PR regimen. DCV+ASV can benefit both the public health and reimbursement system in China.

[On-farm conservation and utilization of paddy rice, wheat and maize landrace varieties in 15 unique ethnic groups in Yunnan, China].

On-farm conservation and utilization of crop landraces have been proposed as means of conserving plant germplasm, in contrast to ex situ germplasm conservation, but little is known about the effectiveness of this approach. This paper reports the findings from a survey conducted in 15 unique ethnic groups of the Yunnan Province on the conservation and utilization of paddy rice, wheat (including wheat, barley, oats, and rye) and maize landrace varieties through participatory rural appraisal (PRA) and questionnaires. The surveyed regions covered 306 villages (the village group) from 237 administrative villages in 124 towns (township) distributed in 36 counties of 11 prefectures (city) in Yunnan Province. The survey showed that 44.8%, 77.5%, and 37.3% of the visited villages had lost their paddy rice, wheat, and maize landraces, respectively. A total of 901 landraces were collected, including 371 rice, 119 wheat, and 411 maize varieties, respectively. There were 2.9 on-farm varieties on average per village, 3.3, 8.0 and 5.2 varieties on average per 100 households, 1 000 peasants and 100 Ha farmland areas, respectively. Among the 306 villages, two villages (Laomian and Qingkou) maintained the highest crop diversity with 18 varieties (including 10 rice and 8 maize varieties) and 14 paddy rice varieties. Also, on-farm varieties in different ethnic groups varied significantly from each other, ranging from 16 to 120 varieties per group. The diversity of paddy rice varieties was the highest, ranging from 1 to 72, and the diversity was mainly distributed in southern, southwest Yunnan of tropical, subtropical ethnic regions. The wheat varieties ranged from 0 to 47 and distributed in northern, northwest Yunnan of high altitude, temperature, and cold ethnic regions. The maize varieties ranged from 4 to 40. These patterns of variation in on-farm varieties are directly associated with traditional culture and custom for the ethnic minorities and reflect the lack of improved varieties for the local special environments. These findings confirm the role of on-farm conservation in plant genetic resources in China and provide baseline information for better on-farm conservation and utilization of plant germplasm in China.

[Analysis of genetic variation in rice paddy landraces across 30 years as revealed by microsatellite DNA markers].

To reveal the genetic variation of rice paddy landraces across 30 years, we compared the genetic variation of between 6 paddy rice landraces grown in Yuanyang Hani's terraced fields in Yuanyang County, Yunnan Province in the 1970s (past-grown landraces) and 6 paired ones that have been grown during the past decade (current-grown landraces) using 60 SSR markers. The results showed that one to four alleles were amplified in 60 loci and 159 alleles in all the landraces tested. The number of alleles from the current-grown landraces decreased by 7 alleles compared to the past-grown landraces. The average number of alleles (Na), effective number of alleles (Ne), locus polymorphism information content (PIC), and genotype diversity (H') of the past-grown landraces were higher than those of the current-grown landraces, with Na of 2.567>2.450, Ne of 2.052>1.968, PIC of 0.469>0.439, and H' of 0.768>0.722. The average genetic similarity coefficient (GS) of the past-grown landraces was 0.437 with a range from 0.200 to 0.700 based on the 60 SSR markers, and the average GS of the current-grown landraces was 0.473 with a range from 0.117 to 0.667. In conclusion, the genetic diversity in current-grown landraces was decreased compared to the past-grown landraces, and the degree of variation in some of the allele locus varied in different rice landraces as a result of 30 years' natural and artificial selection.