Consumption of green tea or green tea products: is there an evidence for antioxidant effects from controlled interventional studies?

PURPOSE: Epidemiological data suggest that green tea (GT) consumption may protect against cardiovascular diseases (CVDs) and different types of cancer. This effect is attributed primarily to the antioxidant properties of flavanols from GT. This review provides an overview of controlled intervention studies investigating the effect of GT consumption on antioxidant effects ex vivo and in vivo. METHODS: The Medline and Cochrane databases were searched independently by two investigators for controlled intervention studies (English) on GT consumption and antioxidant effects published up to June 2010. Thirty-one studies investigating antioxidant effects ex vivo [plasma antioxidant capacity (AC), DNA's resistance against oxidative induced damage) or in vivo (lipid and protein oxidation, DNA damage] met the criteria. Results were compared by considering the participants, the dose of GT, the amount of ingested flavanols, the duration of supplementation and the investigated biomarkers. RESULTS: The comparison between the studies was difficult as relevant data, e.g., on flavanol concentration in plasma (10 of 31 studies) or on major antioxidants contributing to AC, were often missing. Lipid peroxidation and DNA damage were commonly investigated. Data on protein oxidation are scarce. An antioxidant effect of at least one parameter (increase in AC or reduction of oxidative stress marker) was observed in 15 out of 22 studies by daily consumption of GT, primarily in participants exposed to oxidative stress (smokers or mixed collectives of smokers and non-smokers and physical activity) and in 6 out of 9 studies investigating the bolus consumption of GT. CONCLUSION: There is limited evidence that regular consumption of GT in amounts of at least 0.6-1.5 l/day may increase AC and reduce lipid peroxidation (especially oxidation of LDL). This may contribute to the protection against CVDs and different types of cancer. Beneficial effects seem to be more likely in participants exposed to oxidative challenge.

[Tomatoes and lycopene in prevention and therapy--is there an evidence for prostate diseases?]. / Tomaten und Lykopin in Prävention und Therapie--gibt es eine Evidenz bei Prostataerkrankungen?

Tomatoes are discussed to have an important role in the prevention of and therapy for prostate cancer (PCA). Whether or not they are also useful in the primary and secondary prevention of benign prostate hyperplasia (BPH) is not clear. This review summarises the results of original contributions with a focus on interventional studies. Whereas epidemiological studies on BPH prevention provide no evidence for a preventive potential of tomatoes and tomato products, the majority of interventional trials points to an increased DNA resistance against oxidative-induced damage. Even though their effect on a surrogate marker of the IGF pathway cannot be evaluated so far due to insufficient data, the consumption of tomatoes and tomato products may probably protect from PCA--at least when considering low-grade PCA. Thus, regular consumption of these foods can be recommended for the prevention of PCA. Tomato products might also be useful in the therapy for BPH and PCA. The intake of isolated lycopene does not protect from the development of PCA. However, in the doses achieved by consumption of tomato products, lycopene ingestion might also be effective in PCA therapy.

The donor-acceptor approach allows a black-to-transmissive switching polymeric electrochrome.

In the context of the fast-growing demand for innovative high-performance display technologies, the perspective of manufacturing low-cost functional materials that can be easily processed over large areas or finely printed into individual pixels, while being mechanically deformable, has motivated the development of novel electronically active organic components fulfilling the requirements for flexible displays and portable applications. Among all technologies relying on a low-power stimulated optical change, non-emissive organic electrochromic devices (ECDs) offer the advantage of being operational under a wide range of viewing angles and lighting conditions spanning direct sunlight as desired for various applications including signage, information tags and electronic paper. Combining mechanical flexibility, high contrast ratios and fast response times, along with colour tunability through structural control, polymeric electrochromes constitute the most attractive organic electronics for tomorrow's reflective/transmissive ECDs and displays. Although red, blue and most recently green electrochromic polymers (ECPs) required for additive primary colour space were investigated, attempts to make saturated black ECPs have not been reported, probably owing to the complexity of designing materials absorbing effectively over the whole visible spectrum. Here, we report on the use of the donor-acceptor approach to make the first neutral-state black polymeric electrochrome. Processable black-to-transmissive ECPs promise to affect the development of both reflective and transmissive ECDs by providing lower fabrication and processing costs through printing, spraying and coating methods, along with good scalability when compared with their traditional inorganic counterparts.

Overweight HIV patients with abdominal fat distribution treated with protease inhibitors are at high risk for abnormalities in glucose metabolism - a reason for glycemic control.

BACKGROUND: In HIV patients, disorders in glucose metabolism seem to be side effects of highly active antiretroviral therapy (HAART) which may be favoured by obesity, abdominal fat accumulation and familial disposition for diabetes mellitus (DM). The aim of our study was to identify patients at high risk for abnormalities in glucose metabolism taking into account HAART, familial disposition for DM and anthropometric parameters. METHODS: Plasma glucose, insulin, c-peptide and insulin resistance (homeostasis model assessment, HOMA) were determined in 44 HIV patients [16 without HAART, 19 with protease inhibitors (PI), 9 without PI (non-PI)] and in 11 healthy subjects. Glucose tolerance was determined by standard procedures. Body mass index (BMI), triceps skin fold thickness and waist circumference were measured and the waist-to-hip-ratio was calculated. Familial disposition for DM was assessed by questionnaire. RESULTS: Impaired fasting glucose was observed in 28% of HAART-treated patients (21% with PI, 7% non-PI), in 13% of HAART-naive but none in healthy controls. 58% of PI, 44% of non-PI, 38% of HAART-naive and none of healthy controls had a HOMA-index > 2.5 which indicates insulin resistance. HAART-treated patients had significantly higher fasting glucose levels (PI: 97 +/- 11 mg/dL, p = 0.048; non-PI: 109 +/- 58 mg/dL, p = 0.009) compared to healthy controls (72 +/- 8 mg/dL). HOMA-Index was higher in PI treated patients (3.74 +/- 3.08) than in HIV negative controls (0.95 +/- 0.28, p = 0.018). The duration of HAART (p = 0.045), overweight and familial disposition for DM (p = 0.017) significantly affected fasting glucose among PI users. Waist circumference affected c-peptide (p = 0.046) concentration in these patients. CONCLUSION: HIV patients on long-term PI therapy with overweight and familial disposition for DM are at high risk to develop abnormalities of glucose metabolism. Thus, measurements of HOMA-Index, BMI and waist circumference should be routinely done especially in PI medicated patients.

Lymphocyte proliferation and apoptosis in HIV-seropositive and healthy subjects during long-term ingestion of fruit juices or a fruit-vegetable-concentrate rich in polyphenols and antioxidant vitamins.

OBJECTIVE: We investigated whether ingestion of polyphenols from fruit juices or a fruit-vegetable-concentrate affects lymphocyte proliferation and apoptosis in human immunodeficiency virus (HIV)-seropositive (HIV(+)) and HIV-seronegative (HIV(-)) subjects. DESIGN: Randomized, prospective pilot intervention study. SETTING: University of Bonn, Department of General Internal Medicine. SUBJECTS: A total of 23 HIV(+) subjects from the HIV outpatient clinic, 18 HIV(-) controls. INTERVENTIONS: Subjects ingested either 1 l of fruit juice or 30 ml of fruit-vegetable-concentrate daily for 16 weeks in addition to their regular diet. Lymphocyte proliferation and apoptosis were investigated in peripheral blood mononuclear cells at baseline, during 16-weeks of intervention, and after a 6-week washout. Proliferation was assessed by (3)H-thymidine incorporation and apoptosis by nuclear content as measured by flow cytometry. RESULTS: Supplementation of fruit juices increased phytohemagglutinin-induced lymphocyte proliferation (mitotic index) in HIV(+) patients from 18+/-16 to 40+/-34 (P=0.004) and in healthy controls from 27+/-16 to 51+/-21 (P=0.016). Apoptosis was not affected in HIV(+) patients, but rose in healthy controls from 9+/-10 to 34+/-11 (apoptotic index; P=0.001). Intervention with concentrate did not significantly alter proliferation and apoptosis in HIV(+) and HIV(-) subjects. CONCLUSIONS: Even though apoptosis did not change in HIV(+) subjects, ingestion of polyphenol-rich fruit juices might be favorable to HIV(+) patients due to enhanced proliferation, which could restore disturbances in T-cell homeostasis. In healthy controls, increased lymphocyte proliferation during juice consumption was counterbalanced by increased apoptosis.

Cleavage and purification of prokaryotically expressed HIV gag and env fusion proteins for detection of HIV antibodies in the ELISA.

Parts of the gag p24 and the gp41 transmembrane protein of the human immunodeficiency virus HIV-1 were expressed as fusion proteins in Escherichia coli, using an expression vector carrying aa 1-375 of the lac-Z gene linked to the recognition sequence for the blood coagulation factor Xa. Fusion proteins were cleaved into the bacterial and viral portion and the viral polypeptide was purified by a molecular sieve column. The purified viral antigens were tested with 288 human sera in the enzyme-linked immunosorbent assay (ELISA) technique. Comparison with commercially available tests showed comparable sensitivity and a higher specificity of the gag/env-ELISA for borderline reactive sera.

Cleavage of procaryotically expressed human immunodeficiency virus fusion proteins by factor Xa and application in western blot (immunoblot) assays.

The proteins p15 and p24 of the human immunodeficiency virus (HIV) type 1 gag gene were expressed as fusion proteins in Escherichia coli for detecting antibodies against the acquired immunodeficiency virus by Western blot (immunoblot) analysis. These fusion proteins contain amino acids 1 to 375 of the E. coli beta-galactosidase linked to the viral protein(s) by a recognition sequence for the specific protease factor Xa. They are obtained in large amounts in insoluble inclusion bodies. To avoid ambiguous results caused by cross-reaction of sera with bacterial proteins in Western blots, we purified the recombinant fusion proteins and subsequently removed the bacterial part of the fusions by cleavage with factor Xa. The cleavage mixtures were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto nitrocellulose membranes. The viral proteins obtained by this method did not contain any bacterial proteins or protein fragments. Thus, false-positive results in HIV Western blot analysis with bacterially expressed HIV proteins can be excluded with these purified recombinant viral antigens.

[Serologic AIDS diagnosis with polypeptides obtained by genetic technics of the human immunodeficiency virus (HIV-1)]. / Serologische AIDS-Diagnostik mit gentechnisch gewonnenen Polypeptiden des menschlichen Immundefizienz-Virus (HIV-1).

Serologic testing for human immunodeficiency virus type 1 (HIV-1) is currently based on enzyme linked immunosorbent assay (ELISA) as screening method. Positive ELISA-results have to be confirmed by at least one second procedure such as Western blotting or immunofluorescence. To obtain new diagnostic reagents for confirmatory testing, we expressed viral antigens in procaryotic systems. Peptides representing epitopes of structural core (gag)- and envelope (env)-proteins of HIV were produced in E. coli as stable immunogenic beta-galactosidase fusion proteins. Recombinant proteins were taken for immunoblot-assays. The results of Western blotting with those fusion proteins were in general comparable with conventional ELISA, immunofluorescence, immunoblot with cell-culture derived virus and commercially available ELISA tests based on recombinant proteins. Immunoblots using recombinant transmembrane protein (gp41) derived polypeptide were more sensitive than the conventional procedure with purified virion proteins. Western blotting with recombinant fusionproteins provide reliable and inexpensive serodiagnostics without handling of infectious cell cultures.