Trends in temporal and spatial changes of Japanese encephalitis in Chinese Mainland, 2004-2019: a population-based surveillance study

BACKGROUND

Japanese encephalitis (JE) is a serious health concern in China, with approximately 80% of global infections occurring in China. To develop effective prevention and control strategies, this study explored the epidemiological characteristics of JE in China based on spatiotemporal data, to understand the patterns and trends of JE incidence in different regions and time periods.

METHOD

The incidence and mortality rates of JE were extracted from the Public Health Data Center, the official website of the National Health Commission of the People's Republic of China, and the National Notifiable Infectious Disease Surveillance System from 2004 to 2019. Joinpoint regression was applied to examine the spatiotemporal patterns and annual percentage change in incidence and mortality of the JE.

RESULTS

From 2004 to 2019, a total of 43,569 cases of JE were diagnosed, including 2,081 deaths. The annual incidence rate of JE decreased from 0.4171/100,000 in 2004 to 0.0298/100,000 in 2019, with an annual percentage change (APC) of -13.5% (P<0.001). The annual mortality rate of JE showed three stages of change, with inflection points in 2006 and 2014. The incidence and mortality rates of JE have declined in all provinces of China, and more cases were reported in 0-14 years of age, accounting for nearly 80% of all patients.

CONCLUSIONS

The morbidity and mortality rates of JE in China are generally on a downward trend, and emphasis should be placed on strengthening disease surveillance in special areas and populations, popularizing vaccination, and increasing publicity.

[Study on characteristic chromatogram and content determination of Wuzhuyu Decoction reference sample]

In this study, the critical quality attributes of Wuzhuyu Decoction reference sample were explored by using characteristic chromatogram, index component content and dry extract rate as indexes.The dissemination relationship of quantity value between medicinal materials-decoction pieces-reference sample was investigated to preliminarily formulate the quality standard of the reference sample.The characteristic chromatogram of 15 batches of Wuzhuyu Decoction was established by high performance liquid chromatography(HPLC) and the similarity analysis was conducted.Common peaks were demarcated and assigned to medicinal materials.Moreover, quantitative determination of limonin, evodiamine, rutaecarpine and ginsenoside Rb_1 of Wuzhuyu Decoction were performed.The dissemination of quantity value was explored combined with dry extract rate, similarity of characteristic chromatogram and transfer rate of index component content.A total of 18 common peaks were identified in the corresponding materials of Wuzhuyu Decoction reference sample, with the similarity of characteristic chromatogram greater than 0.9, and Fructus Evodiae, Radix Ginseng, Rhizoma Zingiberis Recens and Fructus Jujubae contributed 9, 5, 8 and 2 chromatographic peaks, respectively.The index component content of corresponding materials and the transfer rates of medicinal materials-decoction pieces and decoction pieces-reference sample of different batches of Wuzhuyu Decoction reference sample were as follows: the content of limonin was 0.16%-0.51%, and the transfer rates were 83.66%-115.60% and 38.54%-54.58%, respectively; the content of evodiamine was 0.01%-0.11%, the transfer rated were 80.80%-116.15% and 3.23%-12.93%, respectively; the content of rutaecarpine was 0.01%-0.05%, the transfer rates were 84.33%-134.53% and 5.72%-21.24%, respectively; the content of ginsenoside Rb_1 was 0.06%-0.11%, and the transfer rates were 90.00%-96.92% and 32.45%-67.24%, respectively.The dry extract rate of the whole prescription was 22.58%-29.89%.In this experiment, the dissemination of quantity value of Wuzhuyu Decoction reference sample was analyzed by the combination of characteristic chromatogram, index component content and dry extract rate.A scientific and stable quality evaluation method of the reference sample was preliminarily established, which provided basis for the subsequent development of Wuzhuyu Decoction and the quality control of related preparations.

Integrative analysis of multi-omics data to detect the underlying molecular mechanisms for obesity in vivo in humans

BACKGROUND

Obesity is a complex, multifactorial condition in which genetic play an important role. Most of the systematic studies currently focuses on individual omics aspect and provide insightful yet limited knowledge about the comprehensive and complex crosstalk between various omics levels.

SUBJECTS AND METHODS

Therefore, we performed a most comprehensive trans-omics study with various omics data from 104 subjects, to identify interactions/networks and particularly causal regulatory relationships within and especially those between omic molecules with the purpose to discover molecular genetic mechanisms underlying obesity etiology in vivo in humans.

RESULTS

By applying differentially analysis, we identified 8 differentially expressed hub genes (DEHGs), 14 differentially methylated regions (DMRs) and 12 differentially accumulated metabolites (DAMs) for obesity individually. By integrating those multi-omics biomarkers using Mendelian Randomization (MR) and network MR analyses, we identified 18 causal pathways with mediation effect. For the 20 biomarkers involved in those 18 pairs, 17 biomarkers were implicated in the pathophysiology of obesity or related diseases.

CONCLUSIONS

The integration of trans-omics and MR analyses may provide us a holistic understanding of the underlying functional mechanisms, molecular regulatory information flow and the interactive molecular systems among different omic molecules for obesity risk and other complex diseases/traits.

Antibody response in COVID-19 patients with and without re-positive RT-PCR results during the convalescent phase

Nucleic acid testing and antibody testing data from 143 recovered COVID-19 patients during the convalescent phase were retrospectively analyzed. A total of 23 (16.1%) recovered patients re-tested positive for SARS-CoV-2 RNA by RT-PCR. Three months after symptom onset, 100% and 99.3% of the patients remained positive for total and IgG antibodies, and the antibody levels remained high. IgM antibodies declined rapidly, with a median time to seroconversion of 67 (95% CI: 59, 75) days after onset. Approximately 25% of patients were seronegative for IgA antibodies at three months after onset. There was no statistically significant difference in antibody kinetics between patients with and without re-positive RT-PCR results during the convalescent phase.

Urban-rural differences in catastrophic health expenditure among households with chronic non-communicable disease patients: evidence from China family panel studies

Background

The prevalence of chronic non-communicable diseases (NCDs) challenges the Chinese health system reform. Little is known for the differences in catastrophic health expenditure (CHE) between urban and rural households with NCD patients. This study aims to measure the differences above and quantify the contribution of each variable in explaining the urban-rural differences.

Methods

Unbalanced panel data were obtained from the China Family Panel Studies (CFPS) conducted between 2012 and 2018. The techniques of Fairlie nonlinear decomposition and Blinder-Oaxaca decomposition were employed to measure the contribution of each independent variable to the urban-rural differences.

Results

The CHE incidence and intensity of households with NCD patients were significantly higher in rural areas than in urban areas.

The urban-rural differences in CHE incidence increased from 8.07% in 2012 to 8.18% in 2018, while the urban-rural differences in CHE intensity decreased from 2.15% in 2012 to 2.05% in 2018. From 2012 to 2018, the disparity explained by household income and self-assessed health status of household head increased to some extent. During the same period, the contribution of education attainment to the urban-rural differences in CHE incidence decreased, while the contribution of education attainment to the urban-rural differences in CHE intensity increased slightly.

Conclusions

Compared with urban households with NCD patients, rural households with NCD patients had higher risk of incurring CHE and heavier economic burden of diseases. There was no substantial change in urban-rural inequality in the incidence and intensity of CHE in 2018 compared to 2012. Policy interventions should give priority to improving the household income, education attainment and health awareness of rural patients with NCDs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10887-6.

Clinical characteristics and follow-up analysis of 324 discharged COVID-19 patients in Shenzhen during the recovery period

Objectives: Research on recovering COVID-19 patients could be helpful for containing the pandemic and developing vaccines, but we still do not know much about the clinical features, recovery process, and antibody reactions during the recovery period. Methods: We retrospectively analysed the epidemiological information, discharge summaries, and laboratory results of 324 patients. Results: In all, 15 (8.62%) patients experienced chest distress/breath shortness, where 8 of the 15 were severely ill. This means severely ill patients need an extended amount of time to recover after discharge; next, 20 (11.49%) patients experienced anxiety and 21 (12.07%) had headache/insomnia and a small fraction of them complained of anosmia/ageusia, indicating that these patients need treatment for mental and psychological health issues. Regarding the re-positive patients, their CT and laboratory test results showed no obvious evidence of illness progress or infectivity but a high anti-SARS-CoV-2 antibody expression. Conclusion: Recovered COVID-19 patients need psychological and physiological care and treatment, re-positivity can occur in any person, but juveniles, females, and patients with mild/moderate existing symptoms have higher rates of re-positivity, While there is no evidence that turning re-positive has an impact on their infectivity, but it still alerted us that we need differentiate them in the following managements.

Detecting potential causal relationship between multiple risk factors and Alzheimer's disease using multivariable Mendelian randomization

BACKGROUND

Alzheimer's disease (AD) is a progressive brain disorder characterized by cognitive skills deterioration that affects many elderly individuals. The identified genetic loci for AD failed to explain the large variability in AD and very few causal factors have been identified so far.

RESULTS

mvMR showed that increasing years of schooling (OR=0.674, 95%CI: 0.571-0.796, P=3.337E-06) and genetically elevated HDL cholesterol (OR ranging from 0.697 to 0.830, P=6.940E-10) were inversely associated with AD risk, genetically predicted total cholesterol (OR=1.300, 1.196 to 1.412; P=6.223E-10) and LDL cholesterol (OR=1.193, 1.097 to 1.296, P=3.564E-05) were associated with increasing AD risk. Genetically predicted FG was suggestively associated with increased AD risk. Furthermore, MR-BMA analysis also confirmed FG and years of schooling as two of the top five causal risk factors for AD.

CONCLUSIONS

Our findings might provide us novel insights for treatment and intervention into the causal risk factors for AD or AD-related complex diseases.

METHODS

By using extension methods of Mendelian randomization (MR)--multivariable MR (mvMR) and MR based on Bayesian model averaging (MR-BMA), we intend to estimate the potential causal relationship between nine risk factors and AD outcome and try to prioritize the most causal risk factors for AD.

Inequity in inpatient services utilization: a longitudinal comparative analysis of middle-aged and elderly patients with the chronic non-communicable diseases in China

Background

Aging and the chronic non-communicable diseases (NCDs) challenge the Chinese government in the process of providing hospitalization services fairly and reasonably. The Chinese government has developed the basic medical insurance system to solve the problem of “expensive medical cost and difficult medical services” for vulnerable groups and alleviate the unfair phenomenon. However, few studies have confirmed its effect through longitudinal comparison. This study aimed to explore the trend in the inequity of inpatient use among middle-aged and elderly individuals with NCDs in China.

Methods

This longitudinal comparative study was based on CHARLS data in 2011, 2013 and 2015. Concentration index (CI) was used to measure the variation trend of inequity of inpatient services utilization, while the decomposition method of the CI was applied to measure the factors contributing to inequity in inpatient services utilization. The effect of each factor on the change of inequity in inpatient services utilization was divided into the change of the elasticity and the change of inequality using the Oaxaca-type decomposition method.

Results

The affluent middle-aged and elderly patients with NCDs used more inpatient services than poor groups. The per capita household consumption expenditure (PCE) and Urban Employee Basic Medical Insurance (UEBMI) contributed to the decline in pro-rich inequality of inpatient use, while the New Rural Cooperative Medical Scheme (NRCMS) contributed to the decline in pro-poor inequality of inpatient use.

Conclusions

There was a certain degree of pro-rich unfairness in the probability and frequency of inpatient services utilization for middle-aged and elderly individuals with NCDs in China. The decrease of pro-wealth contribution of PCE and UEBMI offset the decrease of pro-poor contribution of NRCMS, and improved the equity of inpatient services utilization, favoring poor people.

[Research advances in the mammalian target of rapamycin signaling pathway and its inhibitors in treatment of hepatocellular carcinoma]

Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase in the downstream of the phosphatidylinositol 3-kinases (PI3K) family. This kinase plays an important role in the development and progression of hepatocellular carcinoma (HCC). Preclinical data demonstrate that 40%-50% of HCC patients have dysregulated expression of the effectors of the mTOR signaling pathway, and the activation of the mTOR pathway is associated with poorly differentiated tumors, early tumor recurrence, and poor survival/prognosis. This article reviews the research advances in the potential role of the mTOR signaling pathway and its inhibitors in the treatment of HCC.

Age at menarche and osteoporosis: A Mendelian randomization study

PURPOSE

Traditional epidemiological studies suggest that there is an association between age at menarche (years) (AAM) and bone mineral density (BMD) at the sites of the femoral neck and lumbar spine (FNK and LS BMD), indicating a potentially important relationship between AAM and the development of osteoporosis (OP). However, these findings may be influenced by unmeasured confounding factors that can obscure the true relationship between the phenotypic traits. Therefore, we performed Mendelian randomization (MR) analyses to determine whether there is a causal relationship between AAM and BMD (FNK and LS BMD), where late AAM may increase the risk of developing OP.

METHODS

Adopting a two-sample MR approach we incorporated genome-wide association (GWAS) summary statistics from the Reproductive Genetics (ReproGen) Consortium (n = 182,416) (females only) and the GEnetic Factors for OSteoporosis (GEFOS) Consortium (n = 53,236) (both males and females).

RESULTS

Using this MR approach we discovered that each additional year in AAM is associated with a modest reduction in FNK BMD (β = -0.072 se = 0.022, 95% CI (-0.115, -0.030), p = 0.001) and LS BMD ((β = -0.072, se = 0.025, 95% CI (-0.121, -0.023), p = 0.004), and therefore influences OP susceptibility.

CONCLUSIONS

This study demonstrates that AAM in females may play a causal role in OP etiology and provides novel insights into the pathophysiology of bone related diseases like osteoporosis, osteopenia and fracture.

SUMMARY

Our study demonstrates that AAM in females may play a causal role in OP etiology and provides novel insights into the pathophysiology of bone related diseases like osteoporosis, osteopenia and fracture. By adopting Mendelian Randomization approaches, our study was not susceptible to bias from unmeasured confounders or reverse causation.

Additional common variants associated with type 2 diabetes and coronary artery disease detected using a pleiotropic cFDR method

Genome-wide association studies (GWASs) have been performed extensively in diverse populations to identify single nucleotide polymorphisms (SNPs) associated with complex diseases or traits. However, to date, the SNPs identified fail to explain a large proportion of the variance of the traits/diseases. GWASs on type 2 diabetes (T2D) and coronary artery disease (CARD) are generally performed as single-trait studies, rather than analyzing the related traits simultaneously. Despite the extensive evidence suggesting that these two phenotypes share both genetic and environmental risk factors, the shared overlapping genetic biological mechanisms between these traits remain largely unexplored. Here, we adopted a recently developed genetic pleiotropic conditional false discovery rate (cFDR) approach to discover novel loci associated with T2D and CARD by incorporating the summary statistics from existing GWASs of these two traits. Applying the cFDR level of 0.05, 33 loci were identified for T2D and 34 loci for CARD, 9 of which for both. By incorporating pleiotropic effects into a conditional analysis framework, we observed that there is significant pleiotropic enrichment between T2D and CARD. These findings may provide novel insights into the etiology of T2D and CARD, as well as the processes that may influence disease development both individually and jointly.

Improved detection of genetic loci in estimated glomerular filtration rate and type 2 diabetes using a pleiotropic cFDR method

Genome-wide association studies (GWAS) have been shown to have the potential of explaining more of the "missing heritability" of complex human phenotypes by improving statistical approaches. Here, we applied a genetic-pleiotropy-informed conditional false discovery rate (cFDR) to capture additional polygenic effects associated with estimated glomerular filtration rate (creatinine) (eGFRcrea) and type 2 diabetes (T2D). The cFDR analysis improves the identification of pleiotropic variants by incorporating potentially shared genetic mechanisms between two related traits. The Q-Q and fold-enrichment plots were used to assess the enrichment of SNPs associated with eGFRcrea or T2D, and Manhattan plots were used for showing chromosomal locations of the significant loci detected. By applying the cFDR method, we newly identified 74 loci for eGFRcrea and 3 loci for T2D with the cFDR criterion of 0.05 compared with previous related GWAS studies. Four shared SNPs were detected to be associated with both eGFRcrea and T2D at the significant conjunction cFDR level of 0.05, and these shared SNPs had not been reported in previous studies. In addition, we used DAVID analysis to perform functional analysis of the shared SNPs' annotated genes and found their potential hidden associations with eGFRcrea and T2D. In this study, the cFDR method shows the feasibility to detect more genetic variants underlying the heritability of eGFRcrea and T2D, and the overlapping SNPs identified could be regarded as candidate loci that provide a thread of genetic mechanisms between eGFRcrea and T2D in future research.

Novel Common Variants Associated with Obesity and Type 2 Diabetes Detected Using a cFDR Method

Genome-wide association studies (GWASs) have been performed extensively in diverse populations to identify single nucleotide polymorphisms (SNPs) associated with complex diseases or traits. However, to date, the SNPs identified fail to explain a large proportion of the variance of the traits/diseases. GWASs on type 2 diabetes (T2D) and obesity are generally focused on individual traits independently, and genetic intercommunity (common genetic contributions or the product of over correlated phenotypic world) between them are largely unknown, despite extensive data showing that these two phenotypes share both genetic and environmental risk factors. Here, we applied a recently developed genetic pleiotropic conditional false discovery rate (cFDR) approach to discover novel loci associated with BMI and T2D by incorporating the summary statistics from existing GWASs of these two traits. Conditional Q-Q and fold enrichment plots were used to visually demonstrate the strength of pleiotropic enrichment. Adopting a cFDR nominal significance level of 0.05, 287 loci were identified for BMI and 75 loci for T2D, 23 of which for both traits. By incorporating related traits into a conditional analysis framework, we observed significant pleiotropic enrichment between obesity and T2D. These findings may provide novel insights into the etiology of obesity and T2D, individually and jointly.

Novel common variants associated with body mass index and coronary artery disease detected using a pleiotropic cFDR method

Genome-wide association studies (GWAS) have been successfully applied in identifying single nucleotide polymorphisms (SNPs) associated with body mass index (BMI) and coronary heart disease (CAD). However, the SNPs to date can only explain a small percentage of the genetic variances of traits. Here, we applied a genetic pleiotropic conditional false discovery rate (cFDR) method that combines summary statistic p values from different multi-center GWAS datasets, to detect common genetic variants associated with these two traits. The enrichment of SNPs associated with BMI and CAD was assessed by conditional Q-Q plots and the common variants were identified by the cFDR method. By applying the cFDR level of 0.05, 7 variants were identified to be associated with CAD (2 variants being novel), 34 variants associated with BMI (11 variants being novel), and 3 variants associated with both BMI and CAD (2 variants being novel). The SNP rs653178 (ATXN2) is noteworthy as this variant was replicated in an independent analysis. SNP rs12411886 (CNNM2) and rs794356 (HIP1) were of note as the annotated genes may be associated with processes that are functionally important in lipid metabolism. In conclusion, the cFDR method identified novel variants associated with BMI and/or CAD by effectively incorporating different GWAS datasets.

Isolation, identification, and biocontrol of antagonistic bacterium against Botrytis cinerea after tomato harvest

Tomato is one of the most important vegetables in the world. Decay after harvest is a major issue in the development of tomato industry. Currently, the most effective method for controlling decay after harvest is storage of tomato at low temperature combined with usage of chemical bactericide; however, long-term usage of chemical bactericide not only causes pathogen resistance but also is harmful for human health and environment. Biocontrol method for the management of disease after tomato harvest has great practical significance. In this study, antagonistic bacterium B-6-1 strain was isolated from the surface of tomato and identified as Enterobacter cowanii based on morphological characteristics and physiological and biochemical features combined with sequence analysis of 16SrDNA and ropB gene and construction of dendrogram. Effects of different concentrations of antagonistic bacterium E. cowanii suspension on antifungal activity after tomato harvest were analyzed by mycelium growth rate method. Results revealed that antifungal activity was also enhanced with increasing concentrations of antagonistic bacterium; inhibitory rates of 1 × 10⁵ colony-forming units (cfu)/mL antagonistic bacterial solution on Fusarium verticillioides, Alternaria tenuissima, and Botrytis cinerea were 46.31%, 67.48%, and 75.67%, respectively. By using in vivo inoculation method, it was further confirmed that antagonistic bacterium could effectively inhibit the occurrence of B. cinerae after tomato harvest, biocontrol effect of 1 × 10⁹ cfu/mL zymotic fluid reached up to 95.24%, and antagonistic bacterium E. cowanii has biocontrol potential against B. cinerea after harvest of fruits and vegetables.

Characterizing and marker-assisting a novel chili pepper (Capsicum annuum L.) yellow bud mutant with cytoplasmic male sterility

Cytoplasmic male sterility (CMS) in pepper is a better way to produce hybrid seeds compared to manual production. We used the two sequence characterized amplified region (SCAR) markers (CRF-SCAR and CMS-SCAR₁₃₀) in CMS pepper, to identify the genotype. We assembled two CMS yellow bud mutants (YBM; YBM12-A and YBM12-B). This mutation in leaf color is controlled by a single dominant nuclear gene. The aim was to create a new hybrid seed production method that reduces the costs and increases F₁ hybrid seed purity. The results suggest that the CRF-SCAR and CMS-SCAR₁₃₀ markers can be used together in multiple generations to screen for restorer or maintainer genes. We found the marker linked to the restorer gene (Rf) in the C-line and F₁ hybrids, as well as partially in the F₂ generation, whereas it was not found in the sterile YBM12-A or the maintainer line YBM12-B. In the F₂ population, sterility and fertility segregated at a 3:1 ratio based on the CRF-SCAR marker. A 130 bp fragment was produced in the YBM12-A, F₁, and F₂ populations, suggesting that these lines contained sterile cytoplasm. A 140 bp fragment present in the YBM12-B and C-line indicated that these lines contained normal cytoplasm. In addition, we identified some morphological characters distinguishing sterile and fertile buds and flowers that may be linked to the sterility gene. If more restorer lines are identified, CMS expressing the YBM trait can be used in hybrid seed production.

Elevated Type II Secretory Phospholipase A2 Increases the Risk of Early Atherosclerosis in Patients with Newly Diagnosed Metabolic Syndrome

A critical association between type II secretory phospholipase A2 (sPLA2-IIa) and established atherosclerotic cardiovascular disease has been demonstrated. However, the contribution of sPLA2-IIa to early atherosclerosis remains unknown. This study investigated the association between early-stage atherosclerosis and sPLA2-IIa in metabolic syndrome (MetS) patients. One hundred and thirty-six MetS patients and 120 age- and gender-matched subjects without MetS were included. Serum sPLA2-IIa protein levels and activity were measured using commercial kits. Circulating endothelial activation molecules (vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), E-selectin, and P-selectin), and carotid intima-media thickness (cIMT), were measured as parameters of vascular endothelial dysfunction and early atherosclerosis. MetS patients exhibited significantly higher sPLA2-IIa protein and activity levels than the controls. Both correlated positively with fasting blood glucose and waist circumference in MetS patients. Additionally, MetS patients exhibited strikingly higher levels of endothelial activation molecules and increased cIMT than controls. These levels correlated positively with serum sPLA2-IIa protein levels and activity. Moreover, multivariate analysis showed that high sPLA2-IIa protein and activity levels were independent risk factors of early atherosclerosis in MetS patients. This study demonstrates an independent association between early-stage atherosclerosis and increased levels of sPLA2-IIa, implying that increased sPLA2-IIa may predict early-stage atherosclerosis in MetS patients.

Two Dimensional Antiferromagnetic Chern Insulator: NiRuCl6

Density functional theory (DFT) and Berry curvature calculations show that quantum anomalous Hall effect (QAHE) can be realized in two-dimensional(2D) antiferromagnetic (AFM) NiRuCl₆. The results indicate that NiRuCl₆ behaves as an AFM Chern insulator and its spin-polarized electronic structure and strong spin-orbit coupling (SOC) are responsible for the QAHE. By tuning SOC, we found that the topological property of NiRuCl₆ arises from its energy band inversion. Considering the compatibility between the AFM and insulators, AFM Chern insulator provides a new way to archive high temperature QAHE in experiments due to its different magnetic coupling mechanism from that of ferromagnetic (FM) Chern insulator.

Band gap engineering of early transition-metal-doped anatase TiO₂: first principles calculations

The thermal stability and electronic structures of anatase TiO2 doped with early transition metals (TM) (group III-B = Sc, Y and La; group IV-B = Zr and Hf; group V-B = V, Nb and Ta) have been studied using first principles calculations. It was found that all doped systems are thermodynamically stable, and their band gaps were reduced by 1-1.3 eV compared to pure TiO2. Doping with transition metals affects the strength of the hybrid orbital of TM-O bonding, and the band gap increases approximately linearly with the MP value of TM-O bonding.

Correlation between the band gap, elastic modulus, Raman shift and melting point of CdS, ZnS, and CdSe semiconductors and their size dependency

With structural miniaturization down to the nanoscale, the detectable quantities of solid materials no longer remain constant but become tunable. For the II-VI semiconductors example, the band gap expands, the elastic modulus increases, the melting point drops, and the Raman optical phonons experience red shift associated with creation of low frequency Raman acoustic modes that undergo blue shift with decreasing the dimensional scale. In order to understand the common origin of the size dependency of these seemingly irrelevant properties, we formulated these quantities for CdS, ZnS, and CdSe semiconductors from the perspectives of bond order-length-strength correlation and the local bond averaging approach. Consistency between the theory predictions and the measured size dependence of these quantities clarified that the undercoordination-induced local strain and quantum entrapment and the varied fraction of undercoordinated atoms of the entire solid correlate these quantities and dominate their size effect.

Size-suppressed dielectrics of Ge nanocrystals: skin-deep quantum entrapment

Although the dielectric behavior of nanostructured semiconductors has been intensively investigated, the physics behind observations remains disputed with possible mechanisms such as quantum confinement and dangling bond polarization. Here we show that theoretical reproduction of the measured dielectric suppression of Ge nanocrystals asserts that the dielectric suppression originates from the shorter and stronger bonds at the skin-deep surface, the associated local densification and quantum entrapment of energy. Coordination-imperfection induced local quantum entrapment perturbs the Hamiltonian that determines the band gap and hence, the process of electron polarization consequently.

[Cognitive-behavior of HIV-positive women of fertility age regarding AIDS in three counties of Henan Province]

OBJECTIVE

To investigate the demographic characteristics of HIV-positive women of fertility age in Henan province and their knowledge and behavior in relation to AIDS.

METHODS

A questionnaire survey was administered to 686 HIV-positive women of fertility age through face to face interview. The demographic characteristics of the respondents and their association with AIDS-related knowledge and behavior were analysed.

RESULTS

Over 90% of respondents had good knowledge about AIDS. Statistically significant differences existed in the knowledge of AIDS and the use of condom among those with different age, education and income (P < 0.05). Age (OR < 1) and annual income (OR > 1) were identified as risk factors of failing to use condoms in regression analysis.

CONCLUSION

Interventions need to be strengthened for HIV-positive women of fertility age, in particular for those who are young and have high incomes.

Mechanically stiffened and thermally softened Raman modes of ZnO crystal

An analytical form connecting the energy shift of Raman modes directly to the bonding identities (order, nature, length, energy) of a specimen and the response of the bonding identities to the applied stimuli of temperature and pressure was presented for a deeper understanding of the atomistic origin of the ZnO Raman shift. Theoretical reproduction based on the BOLS correlation theory [Sun, C. Q. Prog. Solid State Chem. 2007, 35, 1] and the local bond average (LBA) approach [Sun, C. Q. Prog. Mater. Sci. 2009, 54, 179] of the measurements revealed that the thermally softened ZnO Raman modes arise from bond expansion and bond weakening due to vibration and that the pressure-stiffened Raman modes result from bond compression and bond strengthening due to mechanical work hardening. The developed approach could be useful in generalizing the lattice dynamics directly to the process of vibration and relaxation of a representative bond of the specimen under external stimuli.

Energy shifts of Si oxidation states in the system of Si nanocrystals embedded in SiO2 matrix

Energy shifts in the Si 2p levels of the five Si oxidation states Sin+ (n = 0, 1, 2, 3, 4) in the system of Si nanocrystals embedded in SiO2 matrix have been determined. The thermal annealing effect on the energy shifts has been studied. The result suggests that the Si nanocrystals and the SiO2 are thermally stable but the annealing can cause some structural deformations such as changes in the bond lengths and bond angles for the suboxides Si2O and SiO. The energy shifts generally show a linear dependence on the oxidation state n, suggesting that the energy shifts could be mainly determined by the nearest-neighbor oxygen atoms. It is shown that the chemical structures of the system are similar to those of the conventional SiO2/Si system in terms of the energy shifts.

Impedance labelless detection-based polypyrrole protein biosensor

A simple and sensitive electrochemical immunosensor with impedance labelless detection and novel data processing method was investigated. One-step copolymerization was used to electrochemically deposit an antibody impregnated polypyrrole film on a glassy carbon electrode surface for the immunosensor. Impedance measurements provided a labelless or reporterless method to detect antibody (Ab)-antigen (Ag) interactions. Dimensionless analysis was employed to successfully process the measured impedance data. Since the method derived unit impedance change to eliminate or reduce the variation of the bulk electronic properties of Ab/polypyrrole films, the signal to noise ratio (S/N) was significantly improved for high sensitivity and specificity. Nonspecific binding effect was studied by array electrode chips and was found out that the polypyrrole electrode without antibody attachment had much stronger nonspecific binding effect than the Ab/polypyrrole electrode; incubation followed by thoroughly washing significantly reduced the nonspecific interference. 10 pg/ml detection limit and superior specificity were achieved by the method, demonstrating a highly sensitive labelless immunosensor in comparison with the detection limit of ng -microgram/ml for the reported polypyrrole based immunosensors. The electrochemical immunosensors presented in this paper, due to its simplicity, low cost, high sensitivity and superior specificity, could be an invaluable tool for clinical diagnostics and could have potential applications in drug discovery, environmental and food analysis.

BMS-196085: a potent and selective full agonist of the human beta(3) adrenergic receptor

A series of 4-hydroxy-3-methylsulfonanilido-1,2-diarylethylamines were prepared and evaluated for their human beta(3) adrenergic receptor agonist activity. SAR studies led to the identification of BMS-196085 (25), a potent beta(3) full agonist (K(i)=21 nM, 95% activation) with partial agonist (45%) activity at the beta(1) receptor. Based on its desirable in vitro and in vivo properties, BMS-196085 was chosen for clinical evaluation.

Beta 3 agonists. Part 1: evolution from inception to BMS-194449

Screening of the BMS collection identified 4-hydroxy-3-methylsulfonanilidoethanolamines as full beta 3 agonists. Substitution of the ethanolamine nitrogen with a benzyl group bearing a para hydrogen bond acceptor promoted beta(3) selectivity. SAR elucidation established that highly selective beta(3) agonists were generated upon substitution of C(alpha) with either benzyl to form (R)-1,2-diarylethylamines or with aryl to generate 1,1-diarylmethylamines. This latter subset yielded a clinical candidate, BMS-194449 (35).(1)

Accumulation of mitochondrial DNA deletions in the malignant prostate of patients of different ages

It has been shown that mitochondrial DNA (mtDNA) deletion mutations accumulate with age in many tissues of the body. However, to date no one has shown that these deletions occur in the malignant prostate. Therefore, we hypothesize that such deletions do occur in the prostate and increasingly so with advanced age. To test this hypothesis, DNA was isolated from 34 radical prostatectomy specimens, and the entire mitochondrial genome (16.5kb) was amplified using long range PCR (LXPCR). The LXPCR products were visualized by gel electrophoresis, and the presence of low molecular weight (<16kb) bands was considered evidence of large mtDNA deletions. In order to show that these lower molecular weight LXPCR bands were not simply PCR artifact, we also digested mtDNA from a subset of the same patients and did Southern analysis with a mtDNA probe. Southern blots confirmed the existence of large deletions in every sample tested. Furthermore, several of the specific deletions identified by LXPCR were also seen in the Southern blots. From the LXPCR data, we found that as the age of the specimen increased, so did the average number of low molecular weight bands (i.e. deletions). In particular, one prominent band was seen at 1.2kb and became more consistent with advanced age.

[QTL analysis of anther length and ratio of stigma exsertion, two key traits of classification for cultivated rice (Oryza sativa L.) and common wild rice (O. rufipogon Griff.)]

A genetic map including 120 RFLP markers covering 1418.2 cM has been constructed using a BC1 population derived from a cross between common wild rice (Oryza rufipogon Griff.) from Dongxiang, Jiangxi Province, China, and an elite Indica variety Guichao 2. The linkage orders and genetic distances of markers in this map are consistent with the map constructed by Rice Genome Program of Japan except the markers of short arm of Chromosome 1. The QTLs analysis of anther length and ratio of stigma exsertion, two key traits of classification for cultivated rice and common wild rice indicated that there are two QTLs controlling anther length located at the region of C424-G39 of Chromosome 2, and C2807-C1263 of Chromosome 9 respectively. It was also found that there are two QTLs controlling ratio of stigma exsertion, and located at the region of C2289-R1553 of Chromosome 5 and G1149-R1963 of Chromosome 8 respectively. The detected QTLs affecting the key traits of classification for wild rice and cultivated rice will be useful for study of molecular evolution mechanism of cultivated rice.

[The comparison of genetic divergences and its relationships to heterosis revealed by SSR and RFLP markers in rice (Oryza sativa L.)]

Genetic divergences of 57 entries from 6 ecotypes of rice were surveyed by PCR analysis with 48 pairs of SSR and by Southern analysis by 50 RFLP probes. It was indicated that SSR markers detected polymorphism efficiently in comparison to RFLP markers, considering the allele numbers per locus and average gene diversity. Among all of 1,596 pairs, 1,452 pairs of genetic distances based on SSR data (GDSSR) were higher than the genetic distance based on RFLP data (GDRFLP) by average of 0.2492. The average GDSSR of entries within indica subspecies was 0.5483, but GDRFLP was only 0.2776. And the GDSSR and GDRFLP of entries with japonica subspecies were 0.577, 0.2405 respectively. The average GDSSR between varieties of interspecies was 0.8074, and the average GDRFLP was 0.7310. It is suggested that the GDSSR between varieties of introspecies or interspecies are higher than that of GDRFLP. The analysis of correlation between GDSSR and GDRFLP of any entry with other 56 entries indicated that the correlation coefficient for typical Indica or Japonica varieties were higher, but lower for Indica-like or Japonica-like materials. It was also found that the relationships between genetic distance based on these two kinds of markers and the yield of hybrid performance were not significant, but most of the correlation coefficient between heterosis and GDRFLP or GDSSR arrived at highly significant level.

Hydrogen peroxide mediates the cell growth and transformation caused by the mitogenic oxidase Nox1

Nox1, a homologue of gp91phox, the catalytic moiety of the superoxide (O(2)(-))-generating NADPH oxidase of phagocytes, causes increased O(2)(-) generation, increased mitotic rate, cell transformation, and tumorigenicity when expressed in NIH 3T3 fibroblasts. This study explores the role of reactive oxygen species (ROS) in regulating cell growth and transformation by Nox1. H(2)O(2) concentration increased approximately 10-fold in Nox1-expressing cells, compared with <2-fold increase in O(2)(-). When human catalase was expressed in Nox1-expressing cells, H(2)O(2) concentration decreased, and the cells reverted to a normal appearance, the growth rate normalized, and cells no longer produced tumors in athymic mice. A large number of genes, including many related to cell cycle, growth, and cancer (but unrelated to oxidative stress), were expressed in Nox1-expressing cells, and more than 60% of these returned to normal levels on coexpression of catalase. Thus, H(2)O(2) in low concentrations functions as an intracellular signal that triggers a genetic program related to cell growth.

A novel series of highly potent benzimidazole-based microsomal triglyceride transfer protein inhibitors

A series of benzimidazole-based analogues of the potent MTP inhibitor BMS-201038 were discovered. Incorporation of an unsubstituted benzimidazole moiety in place of a piperidine group afforded potent inhibitors of MTP in vitro which were weakly active in vivo. Appropriate substitution on the benzimidazole ring, especially with small alkyl groups, led to dramatic increases in potency, both in a cellular assay of apoB secretion and especially in animal models of cholesterol lowering. The most potent in this series, 3g (BMS-212122), was significantly more potent than BMS-201038 in reducing plasma lipids (cholesterol, VLDL/LDL, TG) in both hamsters and cynomolgus monkeys.

[A study of the genetic diversity of common wild rice (O. rufipogon Griff.) and cultivated rice (O. sativa L.) by RFLP analysis]

The genetic diversity of cultivated rice and common wild rice from 10 countries in Asia were evaluated by RFLP analysis using 44 probes of single copy. We used the parameters such as proportion of polymorphic loci (P), average number of alleles per locus (A), average number genotype per locus (Ng), degree of heterozygate per locus (Ho) and average gene diversity (Hs) showing genetic diversity. It is indicated that the common wild rice from China has the largest genetic diversity in the 10 countries, and the secondary is the common wild rice from India. The results also showed that the genetic diversity in Chinese common wild rice is larger than the genetic diversity in common wild rice of South and Southeast Asia. The average gene diversity (Hs) of South Asian wild rice is higher than Southeast Asian wild rice, while the parameters value of proportion of polymorphic loci (P), average number of alleles per locus (A) and average number genotype per locus (Ng), Southeast Asian wild rice is higher than South Asian wild rice. It is found that the genetic diversity in cultivated rice is obviously lower than in common wild rice. In the detected 44 loci, the number of polymorphic loci on O. sativa is as the same as 3/4 in O. rufipogon, the number of alleles in O. sativa is as the same as 60% in O. rufipogon, the number of genotype in O. sativa is as same as 1/2 in O. rufipogon. In O. sativa, the genetic diversity of indica is larger than that of japonica. O. rufipogon from China have highest value in degree of hetrozygate per locus (Ho), and Ho of wild rice is as two times as cultivated rice. It is showed that in the proceeding of wild rice evolved into cultivated rice, Ho and number of alleles was reduced, and the genetic diversity was decreased.

The effect of pH on the inhibition of bacterial growth by physiological concentrations of butyric acid: implications for neonates fed on suckled milk

Butyric acid is released from milk by pre-intestinal lipases during suckling. It is also known to inhibit bacterial growth. To investigate whether butyric acid may be a significant factor in controlling bacterial growth in the stomach of pre-weaned animals, the ability of butyric acid to inhibit growth of selected bacteria was tested over physiological ranges of pH and butyric acid concentrations. Six enteric and environmental strains of bacteria were used: two strains of Escherichia coli, Klebsiella pneumoniae, Enterococcus faecium, Enterococcus faecalis, and Enterococcus casseliflavus. At pH 4.5 and 5.0, the growth of all organisms was significantly inhibited in the presence of butyrate, and in some cases growth was completely arrested. At pH 6.0, butyric acid did not affect bacterial growth until the concentration reached 40 mM. The maximum concentration of butyric acid available in cow's milk after incubation with pre-gastric lipase is approximately 16 mM, which would be sufficient to prevent growth of the organisms tested at pH values occurring in the stomach. Therefore, butyric acid inhibition of bacterial growth may explain in part, the role of pre-intestinal lipases in young animals' natural defenses against bacteria in ingested food prior to weaning.

Differentiation and classification of parental lines and favorable genic interactions affecting F1 fertility in distant crosses of rice (Oryza sativa L.)

This study was intended to investigate the extent of genetic differentiation in parental lines of rice hybrids and to analyze the genetic basis underlying the fertility phenomenon in distant crosses. Two subsets of rice material (111 entries in total) were used, including 81 doubled-haploid (DH) lines and 30 Indica and Japonica rice varieties or lines (as a control). The DH lines was derived from a heterotic Indica/Japonica cross (Gui630/02428) by anther culture. The materials in the control represent a broad spectrum of the Asian cultivated rice gene pool including landraces, primitive cultivars, historically important cultivars, modern elite cultivars, super rice and parents of superior hybrids. In accordance with the NC II design, 57 out of the DH lines were test-crossed to two important wide compatibility lines: photoperiod-sensitive genetic male sterile (PGMS) line N422s and thermo-sensitive genetic male sterile (TGMS) line Peiai64s. The F1s and their parents, 182 entries in total, were examined for the performance of seven traits in a replicated field trial. All the rice materials was surveyed for polymorphisms using 92 RFLP markers selected from two published molecular marker linkage maps. Genotypes of the F1 hybrids at the molecular-marker loci were deduced from the parental genotypes. The analysis showed that there were two types of genetic differentiation in the two subsets of rice material; that is, qualitative differentiation in the control and quantitative differentiation in the DH lines. In addition, favorable genic interactions (both intra- or inter-locus) contributed to better increase the fertility in hybrids of distant crosses through incorporation of a wide-compatibility line as the female parent. Favorable genic interactions can be applied in hybrid rice breeding programs by selecting parents with an appropriate extent of genetic differentiation.

Dual metalloprotease inhibitors: mercaptoacetyl-based fused heterocyclic dipeptide mimetics as inhibitors of angiotensin-converting enzyme and neutral endopeptidase

A series of 7,6- and 7,5-fused bicyclic thiazepinones and oxazepinones were generated and incorporated as conformationally restricted dipeptide surrogates in mercaptoacyl dipeptides. These compounds are potent inhibitors of angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP) both in vitro and in vivo. Compound 1a, a 7,6-fused bicyclic thiazepinone, demonstrated excellent blood pressure lowering in a variety of animal models characterized by various levels of plasma renin activity and significantly potentiated urinary sodium, ANP, and cGMP excretion in a cynomolgus monkey assay. On the basis of its potency and duration of action, compound 1a (BMS-186716) was advanced into clinical development for the treatment of hypertension and congestive heart failure.

Aminodiol HIV protease inhibitors. Synthesis and structure-activity relationships of P1/P1' compounds: correlation between lipophilicity and cytotoxicity

A series of novel aminodiol inhibitors of HIV protease based on the lead compound 1 with structural modifications at P1' were synthesized in order to reduce the cytotoxicity of 1. We have observed a high degree of correlation between the lipophilicity and cytotoxicity of this series of inhibitors. It was found that appropriate substitution at the para position of the P1' phenyl group of 1 resulted in the identification of equipotent (both against the enzyme and in cell culture) compounds (10l, 10m, 10n, and 15c) which possess significantly decreased cytotoxicity.

New hydroxyethylamine HIV protease inhibitors that suppress viral replication

The synthesis of analogues of AcSerLeuAsn[Phe-HEA-Pro]IleValOMe (1, JG-365; where HEA stands for the hydroxyethylamine unit 2), a tight-binding inhibitor of HIVP, are reported. Systematic modification of the P3 and P3' regions of the inhibitors has led to smaller HIVP inhibitors that inhibit viral replication in HIV-infected and SIV-infected cell cultures. Six aliphatic and/or aromatic derivatives were prepared by replacing residues in the P3 regions of BocLeuAsn[Phe-HEA-Pro]IleValOMe. Aromatic side chains at P3 gave better inhibitors than aliphatic side chains. The better inhibitors in this series contained a beta-naphthylalanine or a biphenyl unit at P3. A second series of HIVP inhibitors were obtained by converting the P3 group into acyl groups. CbzAsn[Phe-HEA-Pro]IlePheOMe and Qua-Asn-[Phe-HEA-Pro]-Ile-Phe-OMe (where Qua = quinolin-2-ylcarbonyl) are potent HIVP inhibitors with Ki values equal to 1.0 and 0.1 nM, respectively. The inhibition constants were determined by using the continuous fluorometric assay developed by Toth and Marshall. The activities of the protease inhibitors for inhibition of SIV replication were determined in vitro using CEM x 174 cells. Inhibition of HIV infection was determined essentially as reported by Pauwels and co-workers. The anti-HIV assay was carried out in culture using CEM cells (a CD4+ lymphocyte line) infected with virus strain HTLV-IIIb with a multiplicity of infection of 0.1. Several analogues inhibited the cytopathic effect at concentrations of 0.1-0.8 microgram/mL. These results establish that good inhibitors of HIV protease that inhibit viral replication in infected lymphocytes in in vitro cell assays can be obtained from JG-365 when the AcSerLeu unit is replaced by aromatic acyl derivatives.

Convergence of somatosensory and baroreceptive inputs onto parabrachio-subfornical organ neurons in the rat: an electrophysiological study

Electrophysiological characteristics were described for neurons of the parabrachial nucleus (PBN) which receive baroreceptive and somatosensory inputs in the rat. Following focal electrical stimulation in the ipsilateral caudal nucleus of the tractus solitarii (NTS), the firing rates of these neurons were increased in 94 (55.6%), and decreased in 38 (22.5%). Fifty-three (54.5%) of 97 PBN neurons tested were excited, and 11 (11.3%) inhibited in response to contralateral common peroneal nerve (CPN) stimulation. Of these neurons, 52 were found to respond to both caudal NTS and CPN stimulation. Effects of subfornical organ (SFO) stimulation were also examined in 151 of 169 parabrachial neurons. 13 (7.7%) were activated antidromically and were located in the lateral division of the PBN, while 34 (22.5%) were affected orthodromically. Stimulation of the caudal NTS resulted in both a fall in the heart rate and changes of PBN neuronal firing rates. Similar effects were elicited by activating peripheral baroreceptors by the administration of phenylephrine, an alpha-adrenergic agonist. These results strongly indicate that: (1) the lateral PBN is involved in central cardiovascular control; (2) somatosensory and baroreceptive messages may converge onto some PBN neurons; and (3) some PBN neurons may relay baroreceptive information from the caudal NTS to the SFO.

Synthesis, conformation, and immunosuppressive activity of cyclosporines that contain epsilon-oxygen (4R)-4-[(E)-butenyl]-4,N-dimethyl-L-threonine analogues in the 1-position

A series of CsA analogues that contain novel epsilon-oxygen isosteres of (4R)-4-[(E)-butenyl]-4,N-dimethyl-L-threonine (MeBmt) in the 1-position were synthesized. The key steps for the syntheses of enantiomerically pure epsilon-oxygen MeBmt analogues 4-7 were based on the stereoselective epoxidation of cis-allylic alcohol derivative 12 with a peracid, followed by the application of a base-catalyzed intramolecular rearrangement of epoxyurethane 15, which was derived from the reaction of epoxy alcohol 14 and methyl isocyanate. All epsilon-oxygen MeBmt analogues have the same stereochemistry and the same functional groups as those on the alpha,beta,gamma-carbons of MeBmt except for the double bond of MeBmt, which is replaced by the -OCH2-group. The syntheses of the peptide portion of CsA analogues followed the strategy we reported previously. The immunosuppressive activities of CsA analogues 28a-e, determined by inhibition of concanavalin A stimulated thymocytes, showed that 28b, which has the closest structural resemblance to MeBmt, retains about 7-10% of activity of CsA, whereas the analogues 28a, 28c, and 28e retain about 2-5% activity. It is interesting to note that 28d, which has the larger benzyl group on the end of the side chain, is about 20-25% as active as CsA. Extensive conformational analyses by 1D and 2D NMR indicated that the conformation of the 33-membered peptide ring system for all CsA analogues was very similar to that of CsA. However, the NMR analyses revealed that the 1-position side chain of all these CsA analogues adopted a novel conformation in chloroform by forming a different intramolecular hydrogen bond between the beta-OH and the epsilon-oxygen of the same residue. The NMR data also suggest that the chloroform conformation of these CsA analogues is similar to the conformation observed in the crystal structure of CsA in that the 1-position side chain is folded across the cyclic peptide ring system.

Synthesis, conformation, and immunosuppressive activities of three analogues of cyclosporin A modified in the 1-position

The syntheses of three new cyclosporin A (CsA) analogues that contain novel MeBmt derivatives in the 1-position are described. The MeBmt analogue that contains an additional methyl group on C4, (2S,3R,6E)-4,4-dimethyl-3-hydroxy-2-(N-methylamino)-6-octenoic acid (MeBm2t), was synthesized in four steps beginning with the reaction of Pmz-Sar-OtBu with (4E)-2,2-dimethyl-4-hexenal. The C4 desmethyl analogue of MeBmt, (2S,3R,6E)-3-hydroxy-2-(N-methylamino)-6-octenoic acid (MeBth), was synthesized in nine steps by a route based on the Sharpless chiral epoxidation procedure. The alkynyl derivative of MeBmt, (2S,3R,4R)-4-methyl-3-hydroxy-2-(N-methylamino)-6-octynoic acid (MeByt), was synthesized by a modification of the procedure described by Tung et al. for the synthesis of MeBmt. Each MeBmt analogue was protected as the N,O-acetonide and coupled with the hexapeptide Abu-Sar-MeLeu-Val-MeLeu-Ala-OBzl. The resulting heptapeptide was deprotected and coupled with Fmoc-D-Ala-MeLeu-MeLeu-MeVal-OH. The resulting undecapeptides were deprotected and cyclized to give the corresponding CsA analogues. Conformational analysis by 1D and 2D NMR methods was carried out for each analogue in chloroform, and the results are compared with the corresponding solution conformations of CsA and dihydrocyclosporin. The immunosuppressive activities of each analogue, determined in concanavalin A stimulated thymocytes, are lower than obtained for CsA. The results establish the important effect the methyl group and the double bond in MeBmt have on the solution conformation of the 1-position residue in CsA and on immunosuppressive activity.

Glucosylsterols in extracts of Euryale ferox identified by high resolution NMR and mass spectrometry

The structures of three glucosylsterols in a glycolipid mixture from the product of the naturally dried medicinal plant Euryale ferox Salisb. have been elucidated by 500 MHz nuclear magnetic resonance and mass spectroscopic methods and characterized as follows: 24-methylcholest-5-enyl-3 beta-O-pyranoglucoside, 24-ethylcholest-5-enyl-3 beta-O-pyranoglucoside, and 24-ethylcholesta-5,22E-dienyl-3 beta-O-pyranoglucoside. These constituents may be the active substances of the medicinal plant.

Synthesis, biological activity, and conformational analysis of (2S,3R,4S)-MeBmt1-cyclosporin, a novel 1-position epimer of cyclosporin A

Cyclosporin A (CsA, 1), an immunosuppressive cyclic undecapeptide, contains a unique amino acid, (4R)-4-[(E)-butenyl]-4,N-dimethyl-L-threonine (MeBmt), that appears to be critically involved in the biological activity of CsA. In order to further explore the effect that structural elements in MeBmt have on the conformation and biological activity of CsA, the 4-epimer of MeBmt [(4S)-MeBmt, 2] and the corresponding CsA analogue [(4S)-MeBmt1-CsA, 3] have been synthesized. Biological assay using concanavalin A stimulated thymocytes indicated that (4S)-MeBmt1-CsA (3) has only 2-4% immunosuppressive activity relative to CsA. The NMR analysis by 1D and 2D NMR methods establishes the conformation of 3, of which the 33-membered cyclic peptide ring system in chloroform is very similar to that of CsA. However, the NMR analysis also reveals that the 1-position side chain orientation in (4S)-MeBmt1-CsA (3) is very different from that of CsA. Specifically, the (4S)-MeBmt alpha,beta-torsion angle (chi 1) has been rotated approximately 120 degrees relative to that of CsA, and the orientation of the butenyl side chain relative to the 33-membered peptide backbond is different. The orientation of the (4S)-MeBmt side chain is consistent with the possible conformations calculated for (4S)-MeBmt1-CsA (3) by using molecular mechanics (in vacuo) calculations. The conformational analysis suggests that the loss of biological activity for 3 results from an altered conformation of the 1-position side chain relative to the peptide backbond due to the changed chirality at C4 of MeBmt.