Simultaneous fractionation of multiple classes of polyphenols from honeybush tea using solid-phase extraction

The structural diversity of polyphenols and the inherent limitations of current extraction techniques pose a challenge to extract polyphenols using a simple and green method. Hence, in this study, a method was developed to simultaneously fractionate multiple classes of polyphenols by only varying ethanol-water solutions. Honeybush tea, which is rich in polyphenols, was selected as a model for this study. Solvent extraction followed by solid-phase extraction (SPE) was developed to obtain a polyphenol-rich fraction from six honeybush samples. Based on a gradient elution programme (10%, 30%, 50%, 70% and 90% (v/v) ethanol-water solution) of SPE, the Strata X cartridge showed a better recovery of most targeted polyphenols under 0.9 mL of the drying volume and 1 mL min⁻¹ of the dispensing speed. The elution programme for fractionating most polyphenols was as follows: single elution with 50% ethanol, followed by twice elution with 70% ethanol. The antioxidant capacity was used to analyse the differences among the polyphenol-rich fractions from six honeybush samples. Principal component analysis (PCA) revealed that unfermented C. genistoides (GG) has the greatest antioxidant capacity among the honeybush species studied. Additionally, mangiferin, isomangiferin and vicenin-2 were the main contributors to the antioxidant capacity in six honeybush fractions according to the correlation study.     

A Case Report of Germline Compound Heterozygous Mutations in the BRCA1 Gene of an Ovarian and Breast Cancer Patient

The germline carrier of the BRCA1 pathogenic mutation has been well proven to confer an increased risk of breast and ovarian cancer. Despite BRCA1 biallelic pathogenic mutations being extremely rare, they have been reported to be embryonically lethal or to cause Fanconi anemia (FA). Here we describe a patient who was a 48-year-old female identified with biallelic pathogenic mutations of the BRCA1 gene, with no or very subtle FA-features. She was diagnosed with ovarian cancer and breast cancer at the ages of 43 and 44 and had a strong family history of breast and gynecological cancers.     

Indoor solid fuel use for heating and cooking with blood pressure and hypertension: A cross-sectional study among middle-aged and older adults in China

A cross-sectional study was conducted to investigate the impact of solid fuel use for heating and cooking on blood pressure (BP) and hypertension, using data from the China Health and Retirement Longitudinal Study (CHARLS). The primary fuels used for indoor heating and cooking were collected by questionnaires, respectively. Hypertension was defined based on self-report of physician's diagnosis, and/or measured BP, and/or anti-hypertensive medication use. Multivariate logistic regression models were constructed to assess the associations. Among 10 450 eligible participants, 68.2% and 57.2% used indoor solid fuel for heating and cooking, respectively. Compared with none/clean fuel users, solid fuel for heating was associated with elevated BP (adjusted β: 2.02, 95% CI: 1.04–3.01 for systolic BP; adjusted β: 1.36, 95% CI: 0.78–1.94 for diastolic BP) and increased risk of hypertension (adjusted odds ratio: 1.15, 95% CI: 1.03–1.29). The impact of indoor solid fuel for heating on BP was more evident in rural and north residents, and hypertensive patients. We did not detect any significant associations between solid fuel use for cooking and BP/hypertension. Indoor solid fuel use is prevalent in China, especially in the rural areas. Its negative impact on BP suggested that modernization of household fuel use may help to reduce the burden of hypertension in China.     

The reported point centromeres of Scheffersomyces stipitis are retrotransposon long terminal repeats

Point centromeres, found in some ascomycete yeasts such Saccharomyces cerevisiae, are very different in structure from the centromeres of other eukaryotes. They are tiny and nonrepetitive and contain only two short conserved sequence motifs. Until recently, point centromeres were thought to have a single evolutionary origin, in the budding yeast family Saccharomycetaceae. Most yeasts outside this family have centromeres that are many kilobases in size. Some have centromeres consisting of a large inverted repeat sequence, others have centromeric clusters of retrotransposons, and a third group including Candida albicans has centromeres with no conserved sequence features. It was recently reported that Scheffersomyces stipitis has point centromeres with a strongly conserved 125-bp core sequence, which is unexpected because S. stipitis is only distantly related to the known point-centromere species. We show here that the 125-bp core sequence is actually part of the long terminal repeat (LTR) of the Ty5-like retrotransposon Tps5, which forms a cluster in the centromeric region of each S. stipitis chromosome. Thus, the LTR of a centromere-associated retrotransposon confers centromere-like mitotic stability when cloned into a plasmid. The centromeric regions of S. stipitis contain three types of Tps5 element (Tps5a, Tps5b, and Tps5c) and a noncoding nonautonomous large retrotransposon derivative.     

Context-Processing Deficits in Schizotypal Personality Disorder.

Research suggests that schizotypal personality disorder (SPD) is a part of the spectrum of schizophrenia-related illnesses. This article hypothesizes that a deficit in the representation and maintenance of context is a core cognitive disturbance in schizophrenia and that SPD individuals should demonstrate context-processing deficits. To test this hypothesis, the authors administered 3 versions of their AX-CPT task, designed to assess context processing, to 35 healthy controls and 26 individuals with DSM-IV SPD. They also administered working memory and selective attention tasks. SPD individuals displayed context representation deficits similar to those found in schizophrenia but did not show the same additional deficits in context maintenance. Context processing was strongly associated with working memory and selective attention performance in the SPD individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential divalent cation requirements uncouple the assembly and catalytic reactions of human immunodeficiency virus type 1 integrase

Previous in vitro analyses have shown that the human immunodeficiency virus type 1 (HIV-1) integrase uses either manganese or magnesium to assemble as a stable complex on the donor substrate and to catalyze strand transfer. We now demonstrate that subsequent to assembly, catalysis of both 3' end processing and strand transfer requires a divalent cation cofactor and that the divalent cation requirements for assembly and catalysis can be functionally distinguished based on the ability to utilize calcium and cobalt, respectively. The different divalent cation requirements manifest by these processes are exploited to uncouple assembly and catalysis, thus staging the reaction. Staged 3' end processing and strand transfer assays are then used in conjunction with exonuclease III protection analysis to investigate the effects of integrase inhibitors on each step in the reaction. Analysis of a series of related inhibitors demonstrates that these types of compounds affect assembly and not either catalytic process, therefore reconciling the apparent disparate results obtained for such inhibitors in assays using isolated preintegration complexes. These studies provide evidence for a distinct role of the divalent cation cofactor in assembly and catalysis and have implications for both the identification and characterization of integrase inhibitors.     

Effect of moderate to very low fat defined formula diets on serum lipids in healthy subjects

Serum total cholesterol, high density lipoprotein (HDL) cholesterol, and triglyceride levels were studied in healthy male and female subjects consuming for one-week periods a diet of conventional food (CF) providing 42% of energy as fat, principally butter fat, and then in random order nutritionally complete, defined formula diets of moderate (32%) to very low (1%) fat content. Compared to CF, the formula with 32% of energy as corn oil lowered serum cholesterol by 25% and the ratio of total to HDL-cholesterol by 13%. Low (9%) and very low (1–3%) fat formulas reduced HDL-cholesterol by as much as 40%, raised the total: HDL-cholesterol ratio by about 20% and raised serum triglyceride levels by as much as 100%. When low and very low fat formulas were ingested for three weeks, these effects persisted although maximal responses occurred during the first week. These results demonstrated that a moderate fat formula diet with a high P/S ratio had a more favorable effect on serum lipid levels than various low fat formulas. Low fat conventional food diets should be studied in long-term controlled metabolic experiments before such diets are recommended to the general population for coronary heart disease or cancer prevention.     

K-winner networks.

A special class of mutually inhibitory networks is analyzed, and parameters for reliable K-winner performance are presented. The network dynamics are modeled using interactive activation, and results are compared with the sigmoid model. For equal external inputs, network parameters that select the units with the larger initial activations (the network converges to the nearest stable state) are derived. Conversely, for equal initial activations, networks that select the units with larger external inputs (the network converges to the lowest energy stable state) are derived. When initial activations are mixed with external inputs, anomalous behavior results. These discrepancies are analyzed with several examples. Restrictions on initial states are derived which ensure accurate K-winner performance when unequal external inputs are used.