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Tag: "cycles" at biology news

BRCA1 causes ovarian cancer through indirect, biochemical route

...vulation, in that women who have regular menstrual cycles through their life without interruption by pregnancy or oral contraceptive use are at highest risk for developing sporadic ovarian cancer," Dubeau explains. "So we had some clues that the cells that control the menstrual cycle-the ovarian granulosa c...

Effective Cancer Treatments Follow The Clock

...n Clock or Bmal1 genes, which essentially damp the cycles of the internal clock may produce very different effect when compared to defects in Cryptochrome gene, which, in contrast, `jams' the circadian clock at the most active point in its cycle.?/p> Biological clocks function in the brain as well as lu...

Glow-in-the-dark zebrafish at UH hold keys to biological clocks

... start. In this case it was exposure to light/dark cycles after the fourth day of development, about the age when the fish start to swim and feed." The researchers used zebrafish (danio rerio) because they yield such a high output of spawn, with hundreds of eggs being laid by each female per week. This giv...

First frozen egg baby born in Canada

...use this success rate is comparable to regular IVF cycles with ICSI using fresh eggs in many IVF centres," says Dr. Tan. Egg freezing is useful for a number of reasons. "The process enables young women diagnosed with cancer to preserve their fertility before undergoing chemotherapy and radiotherapy, which ...

Super predators and mass extinctions

...ficiently low mutation rate, the model can lead to cycles that correspond to our 26 million year mass extinc.... Previous models that do not show these sorts of cycles could be faulty, according to Lipowski, because they failed to account for the effects of limited li...

Elephant seal pups suffer from ocean warming

...ure changes associated with both long-term 25-year cycles and short-term 3-4 year cycles such as those caused by El Niño. Sea lions and fur seals that feed near their rookeries at the surf...

Study reveals candidate targets for anti-retroviral therapeutics

...he proteins encoded by retroviruses and their life cycles in animal cells. Scientists believe that these simple elements in a single-celled organism are a good model for understanding how retroviruses such as HIV interact with their hosts. Yeast has previously been used as a model to help scientists underst...

After a time-shift, mixed signals from the circadian clock

... (SCN). The clock is synchronized to environmental cycles of light and dark. It is well known, from everyday experience, that adjusting to new light schedules takes several days, though the details of how this adaptation takes place are not well understood. Researchers now report findings that suggest this ...

Changing ecosystems throw scientists mega-challenges

... interactions between human activities and natural cycles at different spatial and temporal scales." The report encourages NSF to maintain its foundation-wide emphasis on investigations of coupled human and natural systems, as currently embodied in the Biocomplexity in the Environment program, and discusse...

Discovery clarifies role of peptide in biological clock

...ekeeping mechanism in these cells depends on daily cycles in gene activity. Herzog found in his latest study that the percentage of rhythmic cells in the mutant SCN was very low, and he believes these rhythmic neurons are specialized circadian pacemakers. "We suspect that at least some of the pace making ...

Innovative collaboration brings Arctic science into the classroom

... and addresses how climate change is impacting the cycles of water and chemicals in the environment. Dr. Holmes has also studied desert streams in the southwestern United States, stream/riparian ecosystems in France, and estuaries in Massachusetts. Dr. Holmes earned his Ph.D. from Arizona State University, ...

Analysis Of Human Genome To Predict The Development Of Illnesses

...l graphical representation of the overall cellular cycles involved in the illness and provides information on the evolution of the sickness using the gathered data. Using the appropriate analyses, it enables the measurement of the efficiency of and patient response to the different treatments administered, ...

Research shows smoking adds a decade to reproductive age of IVF patients

...l records of IVF treatment from 1983 to 1995. ICSI cycles were not evaluated as the treatment was not common...es. Of the total, 1,828 of the first IVF treatment cycles were for unexplained subfertility. The overall live birth rate per cycle was 15.2%[2]. It was highe...

How monarch butterflies are wired for navigation

...n the approximately 24 hour activity and metabolic cycles of animals from the simplest insects to humans. Reppert and his colleagues found that key genes responsible for the clock's molecular "ticks" were expressed in a brain region called the dorsolateral protocerebrum. Using tracer molecules, they were su...

Gene controlling circadian rhythms linked to drug addiction

... the mice experience problems with their circadian cycles - not sleeping as much and becoming more hyperactive - they also found cocaine more rewarding than control mice, demonstrated by their strong preference for the location where the drug was administered. In addition, Clock-deficient mice produced mor...

HIV Therapy Greatly Extends Life of Key T Cells, Scientists Find

...observed that in responsive patients, intermittent cycles of IL-2 therapy lead to substantial increases in the number of circulating CD4+ cells. The mechanisms driving this increase as well as its potential clinical significance, however, have remained unclear, note the scientists. Using two relatively new...

Temperature regulates circadian clock in zebrafish

...ses, from fluctuating hormone levels to sleep-wake cycles and feeding patterns. While it's well known that c...es, much less is known about how daily temperature cycles affect the clock's timing mechanism in vertebrates. In the open-access journal PLoS Biology , Kajo...

A novel method to measure circadian cycles

...l PLoS Biology a new method to measure circadian cycles in mammalian cells cultured from tissues other than the suprachiasmatic nucleus. The researchers took skin samples from humans and infected subsequently made tissue cultures with a virus engineered to report with a fluorescent signal when a certain ...

New understanding of jet lag

...iological clock that regulates waking and sleeping cycles - has two parts that fall out of synchrony during ...er from sleep disorders. In nature, day and night cycles shift slowly as the seasons change. The body is able to adjust to the slow changes and is in fact ad...

Vaginal gel may provide a new approach to HIV prevention

...trol (Depo-Provera) to synchronize their menstrual cycles and thin the vaginal membrane, which increases susceptibility to virus infection, Veazey says. During testing, researchers placed the experimental gels in the animals' vaginas. Thirty minutes later, the animals were exposed to high-dose SHIV. The th...

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