DABCO-based chiral ionic liquids as recoverable and reusable organocatalyst for asymmetric Diels–Alder reaction

New DABCO-based chiral ionic liquids were synthesized and evaluated in asymmetric Diels–Alder reaction of cyclopentadiene with α,β-unsaturated aldehydes or 4-phenyl-3-buten-2-one. Chiral ionic liquid of modified MacMillan catalyst having a DABCO cation and hexafluorophosphate anion acts as organocatalyst (5 mol%) for the Diels–Alder reaction of crotonaldehyde and cyclopentadiene producing 98% of the product and 87% ee (endo) in CH₃CN/H₂O (95/5) at 25°C in 2 h. The scope and limitations of the catalysis were also studied by using cyclopentadiene and α,β-unsaturated aldehydes, and the Diels–Alder products were obtained in 18%–92% yields with 68%–93% ee. The catalyst was recycled and reused up to 6 cycles with a slight drop in ee and conversion of the product.     

Association between frailty and 30-day outcomes after discharge from hospital

Background:Readmissions after hospital discharge are common and costly, but prediction models are poor at identifying patients at high risk of readmission. We evaluated the impact of frailty on readmission or death within 30 days after discharge from general internal medicine wards.Methods:We prospectively enrolled patients discharged from 7 medical wards at 2 teaching hospitals in Edmonton. Frailty was defined by means of the previously validated Clinical Frailty Scale. The primary outcome was the composite of readmission or death within 30 days after discharge.Results:Of the 495 patients included in the study, 162 (33%) met the definition of frailty: 91 (18%) had mild, 60 (12%) had moderate, and 11 (2%) had severe frailty. Frail patients were older, had more comorbidities, lower quality of life, and higher LACE scores at discharge than those who were not frail. The composite of 30-day readmission or death was higher among frail than among nonfrail patients (39 [24.1%] v. 46 [13.8%]). Although frailty added additional prognostic information to predictive models that included age, sex and LACE score, only moderate to severe frailty (31.0% event rate) was an independent risk factor for readmission or death (adjusted odds ratio 2.19, 95% confidence interval 1.12–4.24).Interpretation:Frailty was common and associated with a substantially increased risk of early readmission or death after discharge from medical wards. The Clinical Frailty Scale could be useful in identifying high-risk patients being discharged from general internal medicine wards.Readmissions within 30 days after hospital discharge are common and costly occurrences. Although many studies have attempted to identify patients at highest risk of readmission, neither experienced clinicians nor experienced researchers using rigorously developed administrative data-rich algorithms can accurately predict which patients will not successfully transition back into the community.^1–6 This suggests that currently unrecognized factors likely play a major role in readmission risk. Identification of these factors would be important for future initiatives to reduce readmission rates by targeting resources to those at highest risk.Frailty is a frequently underdiagnosed condition, with prevalence estimates ranging from 27% to 80% among inpatients^7–9 and from 4% to 59% among older adults living in the community,¹⁰ depending on the frailty measure used and the population evaluated. Frailty is a multidimensional syndrome of decreased reserve and resistance to stressors leading to increased vulnerability to adverse outcomes.^11–14 The 2 models of frailty most commonly used in the literature are the phenotype model (e.g., the approach proposed by Fried and colleagues,¹⁵ which is based on 5 objective variables assessed at one point in time that do not include psychosocial and cognitive variables) and the cumulative deficit model (e.g., the Clinical Frailty Index, which is based on a mix of more than 30 variables capturing function in many domains over time).^16–18Although the gold standard for frailty assessment is a comprehensive geriatric assessment by a multidisciplinary team, both the phenotype and cumulative deficit models appear reasonably accurate for identifying frailty. However, both are somewhat cumbersome for routine use at the bedside.¹² For these reasons, the Clinical Frailty Scale was developed and relies on clinical judgment based on history taking and clinical examination. The Clinical Frailty Scale is easy to administer at the bedside; has been used by physicians, allied health professionals and research assistants; does not require any special equipment; is highly correlated with the Fried frailty index (r = 0.8);¹⁷ and appears to be valid, reliable and reproducible.¹⁹ Some risk-prediction models, such as the LACE Index, have tried to incorporate frailty, but they did not find it to be a significant independent variable, possibly owing to the frailty measure used. A systematic review of 30 risk-prediction models for hospital readmission found that only 2 included functional status.⁴We conducted a study to evaluate whether frailty identified using the Clinical Frailty Scale is an independent predictor of death or readmission within 30 days after discharge from hospital.     

Stigma and Human Rights Abuses against People Who Inject Drugs in Russia—A Qualitative Investigation to Inform Policy and Public Health Strategies

Introduction

Drug policing practices in the Russian Federation (Russia) are often punitive and have been shown to be associated with HIV risk behaviors among people who inject drugs (PWID). Less is known about strategies to address the problem in that setting, where substance use stigma is highly persistent. A better understanding of forms, causes and consequences of drug policing in Russia could inform drug policy in a context of substantial policy resistance. This qualitative study’s goal is to characterize the phenomenon of police involvement with Russian PWID and to explore strategies for drug policing in the Russian country context.

Methods

Using a semi-structured interview guide, we collected data from a purposive sample of 23 key informants including PWID, police officers, and experts from civil society and international organizations in Russia. We used a thematic analysis approach to inductively generate new insight into the phenomenon of police involvement and potential strategies to address it.

Results

Policing practices involving PWID include unjustified arrests, planting of false evidence and extrajudicial syringe confiscations, and often constitute human rights violations. Russian PWID personally experienced police violence as ubiquitous, taking on various forms such as beating, unjustified arrests, verbal harassment, and coercion. The persistent societal stigma dehumanizes PWID, and such stigmatization facilitates police abuse. To address stigma and overcome the PWID-police adversity, study participants suggested fostering a mutual understanding between the police and public health sectors.

Conclusions

Participants describe substantial human rights violations as part of policing illicit drug use in Russia. Police should include principles of effective prevention of substance use and HIV risk reduction in their trainings. Alignment of public safety and public health goals could address drug use-related risks and HIV prevention among key populations in Russia.     

Photosensitivity in Smith-Lemli-Opitz syndrome: a flux balance analysis of altered metabolism

Ultraviolet A photosensitivity is a debilitating symptom associated with the metabolic disorder Smith-Lemli-Opitz syndrome (SLOS). SLOS is a manifestation of the deficiency of 7-dehydrocholesterol reductase, an enzyme involved in the cholesterol biosynthesis. As a result several abnormal intermediary compounds are formed among which Cholesta 5, 7, 9(11)-trien-3beta-ol is the most likely cause of photosensitivity. The effect of various drugs acting on cholesterol biosynthetic pathway on SLOS is not clear as clinical trials are not available for this rare disorder. A Flux Balance Analysis (FBA) has been carried out using the software CellNetAnalyzer or FluxAnalyzer to gain insight into the probable effects of various drugs acting on cholesterol biosynthetic pathway on photosensitivity in SLOS. The model consisted of 44 metabolites and 40 reactions. The formation flux of Cholesta 5, 7, 9(11)-trien-3beta-ol increased in SLOS and remained unchanged on simulation of the effect of miconazole and SR31747. However zaragozic acid can potentially reduce the flux through the entire pathway. FBA predicts zaragozic acid along with cholesterol supplementation as an effective treatment for photosensitivity in SLOS.     

Long term pharmacotherapy for obesity and overweight: updated meta-analysis

Objective To summarise the long term efficacy of anti-obesity drugs in reducing weight and improving health status.Design Updated meta-analysis of randomised trials.Data sources Medline, Embase, the Cochrane controlled trials register, the Current Science meta-register of controlled trials, and reference lists of identified articles. All data sources were searched from December 2002 (end date of last search) to December 2006.Studies reviewed Double blind randomised placebo controlled trials of approved anti-obesity dugs used in adults (age over 18) for one year or longer.Results 30 trials of one to four years’ duration met the inclusion criteria: 16 orlistat (n=10 631 participants), 10 sibutramine (n=2623), and four rimonabant (n=6365). Of these, 14 trials were new and 16 had previously been identified. Attrition rates averaged 30-40%. Compared with placebo, orlistat reduced weight by 2.9 kg (95% confidence interval 2.5 kg to 3.2 kg), sibutramine by 4.2 kg (3.6 kg to 4.7 kg), and rimonabant by 4.7 kg (4.1 kg to 5.3 kg). Patients receiving active drug treatment were significantly more likely to achieve 5% and 10% weight loss thresholds. Orlistat reduced the incidence of diabetes and improved concentrations of total cholesterol and low density lipoprotein cholesterol, blood pressure, and glycaemic control in patients with diabetes but increased rates of gastrointestinal side effects and slightly lowered concentrations of high density lipoprotein. Sibutramine lowered concentrations of high density lipoprotein cholesterol and triglycerides but raised blood pressure and pulse rate. Rimonabant improved concentrations of high density lipoprotein cholesterol and triglycerides, blood pressure, and glycaemic control in patients with diabetes but increased the risk of mood disorders.Conclusions Orlistat, sibutramine, and rimonabant modestly reduce weight, have differing effects on cardiovascular risk profiles, and have specific adverse effects.     

Human papillomavirus type 16 E1 E4-induced G2 arrest is associated with cytoplasmic retention of active Cdk1/cyclin B1 complexes

Human papillomavirus type 16 (HPV16) can cause cervical cancer. Expression of the viral E1 E4 protein is lost during malignant progression, but in premalignant lesions, E1 E4 is abundant in cells supporting viral DNA amplification. Expression of 16E1 E4 in cell culture causes G2 cell cycle arrest. Here we show that unlike many other G2 arrest mechanisms, 16E1 E4 does not inhibit the kinase activity of the Cdk1/cyclin B1 complex. Instead, 16E1 E4 uses a novel mechanism in which it sequesters Cdk1/cyclin B1 onto the cytokeratin network. This prevents the accumulation of active Cdk1/cyclin B1 complexes in the nucleus and hence prevents mitosis. A mutant 16E1 E4 (T22A, T23A) which does not bind cyclin B1 or alter its intracellular location fails to induce G2 arrest. The significance of these results is highlighted by the observation that in lesions induced by HPV16, there is evidence for Cdk1/cyclin B1 activity on the keratins of 16E1 E4-expressing cells. We hypothesize that E1 E4-induced G2 arrest may play a role in creating an environment optimal for viral DNA replication and that loss of E1 E4 expression may contribute to malignant progression.     

Dynamic model for predicting survival of mature larvae of Tribolium confusum during facility heat treatments

Structural heat treatment, a viable alternative to methyl bromide fumigation, involves raising the ambient temperature of food-processing facilities between 50 and 60 degrees C by using gas, electric, or steam heaters, and holding these elevated temperatures for 24 h or longer to kill stored-product insects. A dynamic model was developed to predict survival of mature larvae, which is the most heat-tolerant stage of the confused flour beetle, Tribolium confusum (Jacquelin du Val), at elevated temperatures between 46 and 60 degrees C. The model is based on two nonlinear relationships: 1) logarithmic survival of T. confusum mature larvae as a function of time, and 2) logarithmic reduction in larval survival as a function of temperature. The dynamic model was validated with nine independent data sets collected during actual facility heat treatments conducted on two separate occasions at the Kansas State University pilot flour and feed mills. The rate of increase of temperature over time varied among the nine locations where mature larvae of T. confusum were exposed, and the approximate heating rates during the entire heat treatment ranged from 1.1 to 13.2 degrees C/h. The absolute deviation in the predicted number of larvae surviving the heat treatment was within 3-7% of the actual observed data. Comparison of the absolute deviation in the time taken for equivalent larval survival showed that the model predictions were within 2-6% of the observed data. The dynamic model can be used to predict survival of mature larvae of T. confusum during heat treatments of food-processing facilities based on time-dependent temperature profiles obtained at any given location.     

Establishing a health demographic surveillance site in Bhaktapur district, Nepal: initial experiences and findings

ABSTRACT: BACKGROUND: A health demographic surveillance site (HDSS) provides longitudinal data regarding health and demography in countries with coverage error and poor quality data on vital registration systems due to lack of public awareness, inadequate legal basis and limited use of data in health planning. The health system in Nepal, a low-income country, does not focus primarily on health registration, and does not conduct regular health data collection. This study aimed to initiate and establish the first HDSS in Nepal. RESULTS: We conducted a baseline survey in Jhaukhel and Duwakot, two villages in Bhaktapur district. The study surveyed 2,712 households comprising a total population of 13,669. The sex ratio in the study area was 101 males per 100 females and the average household size was 5. The crude birth and death rates were 9.7 and 3.9/1,000 population/year, respectively. About 11% of births occurred at home, and we found no mortality in infants and children less than 5 years of age. Various health problems were found commonly and some of them include respiratory problems (41.9%); headache, vertigo and dizziness (16.7%); bone and joint pain (14.4%); gastrointestinal problems (13.9%); heart disease, including hypertension (8.8%); accidents and injuries (2.9%); and diabetes mellitus (2.6%). The prevalence of non-communicable disease (NCD) was 4.3% (95% CI: 3.83; 4.86) among individuals older than 30 years. Age-adjusted odds ratios showed that risk factors, such as sex, ethnic group, occupation and education, associated with NCD. CONCLUSION: Our baseline survey demonstrated that it is possible to collect accurate and reliable data in a village setting in Nepal, and this study successfully established an HDSS site. We determined that both maternal and child health are better in the surveillance site compared to the entire country. Risk factors associated with NCDs dominated morbidity and mortality patterns.     

Cell-based screening for membranal and cytoplasmatic markers using dielectric spectroscopy

Dielectric spectroscopy (DS) of living biological cells is based on the analysis of the complex dielectric permittivity of cells suspended in a physiological medium. It provides knowledge on the polarization–relaxation response of cells to external electric field as function of the excitation frequency. This response is strongly affected by both structural and molecular properties of cells and therefore, can reveal rare insights on cell physiology and behaviour. This study demonstrates the mapping potential of DS after cytoplasmatic and membranal markers for cell-based screening analysis. The effect of membrane permittivity and cytoplasm conductivity was examined using tagged MBA and MDCK cell lines respectively. Comparing the permittivity spectra of tagged and native cell lines reveals clear differences between the analyzed suspensions. In addition, differences on the matching dielectric properties of cells were obtained. Those findings support the high distinction resolution and sensitivity of DS after fine molecular and cellular changes, and hence, highlight the high potential of DS as non invasive screening tool in cell biology research.     

RNA Interference: Biology, Mechanism, and Applications

Double-stranded RNA-mediated interference (RNAi) is a simple and rapid method of silencing gene expression in a range of organisms. The silencing of a gene is a consequence of degradation of RNA into short RNAs that activate ribonucleases to target homologous mRNA. The resulting phenotypes either are identical to those of genetic null mutants or resemble an allelic series of mutants. Specific gene silencing has been shown to be related to two ancient processes, cosuppression in plants and quelling in fungi, and has also been associated with regulatory processes such as transposon silencing, antiviral defense mechanisms, gene regulation, and chromosomal modification. Extensive genetic and biochemical analysis revealed a two-step mechanism of RNAi-induced gene silencing. The first step involves degradation of dsRNA into small interfering RNAs (siRNAs), 21 to 25 nucleotides long, by an RNase III-like activity. In the second step, the siRNAs join an RNase complex, RISC (RNA-induced silencing complex), which acts on the cognate mRNA and degrades it. Several key components such as Dicer, RNA-dependent RNA polymerase, helicases, and dsRNA endonucleases have been identified in different organisms for their roles in RNAi. Some of these components also control the development of many organisms by processing many noncoding RNAs, called micro-RNAs. The biogenesis and function of micro-RNAs resemble RNAi activities to a large extent. Recent studies indicate that in the context of RNAi, the genome also undergoes alterations in the form of DNA methylation, heterochromatin formation, and programmed DNA elimination. As a result of these changes, the silencing effect of gene functions is exercised as tightly as possible. Because of its exquisite specificity and efficiency, RNAi is being considered as an important tool not only for functional genomics, but also for gene-specific therapeutic activities that target the mRNAs of disease-related genes.