Archiv der Kategorie: medicine

Goldene nano-U-Boote im Körper

Mikroskopisch kleine Goldpartikel, beladen mit Medikamenten, Genmaterial oder Stammzellen, sollen dereinst genau den Weg zu Krankheitsherden finden.

(eurekalert) Researchers at The University of Texas M. D. Anderson Cancer Center report that they have created a way for viral and gold particles to „directly assemble“ and potentially seek out and treat disease where it resides in the body. Their study, published in the online early edition of The Proceedings of the National Academy of Sciences (PNAS) the week of Jan. 23 – 27, 2006, shows the use of biologically compatible materials to fabricate a „nanoshuttle“ – thousands of times smaller than a human hair – which can be harnessed to viral particles to precisely home to disease wherever it hides. Once there, the nanoshuttle can perform a variety of functions. The study defines how assembled particles of gold – a metal that is not rejected by the body – could possibly be „tuned“ to destroy tissue or emit signals that can be detected by imaging devices. The system also can be adapted to form a flexible scaffold that can carry drugs, genes or even cradle restorative stem cells.

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Viagra und das Stroboskop

Die Wirkung auf den männlichen Penis ist lediglich eine Nebenwirkung! Unter anderem hat Viagra offenbar auch den Effekt, dass seine Konsumenten in schnellen Rhythmus blinkende Lichter nicht mehr auseinanderhalten können…

(eurekalert) (…) Originally developed as a heart drug, sildenafil citrate (Viagra®) has several side effects, not least of which is that it helps to alleviate erectile dysfunction by prolonging the relaxation of smooth muscle in the corpora cavernosa of the penis, thereby helping to maintain the blood flow required for an erection. A less desirable side effect is that it inhibits the enzyme phosphodiesterase, PDE6, which is in the cone and rod photoreceptors of the eye and is involved in the transduction of photons into neural signals that are decoded by the visual system. The precise effect of Viagra on human visual performance, however, remains somewhat equivocal and anecdotal.

By measuring the ability of human observers to detect flickering lights under various conditions, a team of researchers, including Andrew Stockman of the Institute of Ophthalmology, London, has demonstrated that therapeutic 100 mg doses of Viagra cause transient losses in the sensitivity to flicker. These losses range in severity, from mild to moderate, among observers. In those more affected observers, the losses in flicker sensitivity caused by the inhibition of PDE6 by Viagra are consistent with an almost doubling of the time over which visual events are integrated by the visual system. (…)

Stockman et al.: „Viagra slows the visual response to flicker.“ Current Biology 16, pages R44-R45, January 24, 2006 DOI 10.1016/j.cub.2006.01.016

Schwarze Schoggi tut männlichen Raucherarterien gut

Das Projekt lief in Zürich am Unispital, durchgeführt von Roberto Corti, die Schoggi stammte von eine grossen Lebensmittelkonzern mit Hauptsitz in Vevey. Andere Marken wurden nicht auf die Wirksamkeit hin getestet.
(Heart 2006; 92: 119-20) Dark chocolate may stave off artery hardening in smokers, and a few squares every day could potentially cut the risk of serious heart disease, finds a small study in Heart. Researchers compared the effects of dark (74% cocoa solids) and white chocolate on the smoothness of arterial blood flow in 20 male smokers. In smokers the activity of both endothelial cells, which line the artery walls, and platelets, which are involved in the formation of blood clots, are continuously disrupted, making the arteries susceptible to the narrowing and hardening characteristic of coronary artery disease. Before eating 40 g of chocolate (about 2 oz), smokers were first asked to abstain from other foods rich in antioxidants, such as onions, apples, cabbage, and cocoa products for 24 hours. After two hours, ultrasound scans revealed that dark chocolate significantly improved the smoothness of arterial flow, an effect which lasted for eight hours. Dark chocolate has more antioxidants per gram than other foods laden with the substances, such as red wine, green tea, and berry fruits, say the authors, who suggest that the beneficial effects of dark chocolate lie in its antioxidant content.
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Gegen Kater hilft (fast) nix

(BMJ Volume 331, pp 1515-7) No compelling evidence exists to suggest that any complementary or conventional intervention is effective for treating or preventing alcohol hangover, say researchers in this week’s BMJ. In Britain, alcohol hangovers account for about £2bn in lost wages each year, mostly due to sickness absence, and a plethora of „hangover cures“ is on offer. The team searched medical databases and the internet, and contacted experts and manufacturers for randomised controlled trials of any medical intervention for preventing or treating alcohol hangover. They found eight trials testing eight different agents: propranolol (beta-blocking drug), tropisetron (drug for nausea and vertigo), tolfenamic acid (painkiller), fructose or glucose, and the dietary supplements borage, artichoke, prickly pear, and a yeast based preparation. Most trials reported no beneficial effects, although encouraging findings existed for borage, a yeast based preparation, and tolfenamic acid. „We are confident that our search strategy located all published trials on the subject,“ say the authors. „Our findings show no compelling evidence to suggest that any complementary or conventional intervention is effective for treating or preventing the alcohol hangover.“ The most effective way to avoid the symptoms of alcohol induced hangover is thus to practise abstinence or moderation, they conclude.

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Forum beim New Scientist zur Frage What’s the best way to beat a festive hangover?

Was wurde aus Mehrfachovulation / Mehrfacheisprung?

Vor zweieinhalb Jahren fand ein kanadisches Team heraus, dass einige der beobachteten Frauen in einem Zyklus zwei Eisprünge hatten und dass alle beobachteten Frauen zwei „Wachstumswellen“ in den Eierstöcken zeigten. Beides widerspricht der Lehrbuchmeinung diametral. Seither hab ich nie mehr was von diesen Beobachtungen gehört, die eigentlich die Basis legen könnten für einen klassischen Paradigmenwechsel. Darum hab ich Pierson aus reiner Neugierde soeben ein Mail geschrieben und nachgefragt. Mal schaun, was er antwortet.
(New Scientist) Women may ovulate more than once a month, suggests a Canadian study that overturns conventional views on the human menstrual cycle. The findings may explain why the rhythm method of contraception is so unreliable and could lead to improved, targeted fertility treatments in the future. Ten per cent of the women studied released two eggs in the same month. And all the women examined by researchers at the University of Saskatchewan in Saskatoon, Canada showed at least two waves of maturing eggs in their ovaries in the same month. Traditionally, it has been thought that ovulation takes place only once in every menstruation cycle. (…) „It’s been assumed until now that women have just one wave per monthly cycle, leading to one ovulation, but nobody has actually carried out detailed analysis before,“ said Roger Pierson, who led the study. „In fact, all the women in our study had at least two waves and 30 per cent of them had three.“ Den Originalartikel gibt’s hier.