A Surprising Ally Against Tooth Decay

Cranberries contain a generous portion of anti-oxidents called flavonoids which might inhibit tooth decay according to this linked Science Daily article. Specific beneficial substances in cranberries include quercetin and myricetin, phenolic acids (benzoic acid), anthocyanins and condensed tannins. Substances such as these and others in cranberries help keep teeth healthy by restraining bacterial surface adherance and by inhibiting both acid formation and enzymes implicated in plaque formation.

Some Unexpected Benefits of Green Tea

5 Things You Don't Know About Green Tea is a Healthy Living piece revealing some little known benefits of green tea. Think of teeth, breath, room odors, healthy bones, sunburns, anti-bacterial skin applications and soaking feet. All are mentioned in this brief but significant article of interest to tea aficionados.

A DNA Methylation Discovery Affecting Cancer

Newly found enzymes may play early role in cancer is a EurekAlert article reporting that researchers believe they have identified two enzymes connected with cancer at early stages. The discoveries were the consequence of working with zebrafish. David Jones, Ph.D., is a professor of oncological sciences at the University of Utah. He also is senior director of early translational research at the university's Huntsman Cancer Institute. Jones explained that the manipulation of these enzymes could either slow the development of tumors or even prevent them.

The function of these enzymes seems to entail control of gene expression which, when faulty, can bring on cancer. A hitherto unknown process, involving these enzymes, affects DNA methylation of genes. Methylation is a process sometimes described with the phrase "on and off switch." On and off relate to whether proteins coded for by genes become synthesized and when this occurs. Healthy cellular function requires that timely gene expression occurs. Quoting the article:

The significance of this research is the discovery of two enzymes involved in DNA demethylation. Defects in DNA methylation balance are strongly associated with the early development of cancer, other diseases and birth defects, and the scientists say their study is the first clear evidence that this enzyme system plays a critical role in maintaining this balance. They also believe it's a process that can be reversed.

Professor Jones is quoted as saying:

"We discovered a pair of enzymes that can remove methylated DNA, but if these enzymes work improperly, they will instead enhance the rate of mutations in methylated DNA and cause cancer progression," "The question now is, when they work improperly, can we find ways to shut them off and prevent these mutations?"

A Seven-In-Absentia Approach to Pancreatic Cancer

Blocking Molecular Pathway With Whimsical Name Possible Therapeutic Target For Pancreatic Cancer is a Science Daily article about a potentially productive therapeutic approach to pancreatic cancer. The article points out that cancer of the pancreas is the most lethal of human cancers. A gene known as Seven-In-Absentia (SINA) is the focus of attention for its coded protein appears to perform a check and balance function within a pathway identified as K-RAS. The specifics entail neutralizing growth-promoting proteins through their degradation. Mutated K-RAS genes have been linked to excessive growth of cancerous pancreas cells.

Degarelix

Prostate Cancer Drug Reduces Testosterone Levels In As Little As Three Days Without Initial Hormone Surge is a Science Daily article. The article discusses benefits of degarelix, a gonadotrophin-releasing hormone antagonist and new weapon in the war against prostate cancer. It is new and its use is intended to cause a rapid fall in testosterone. Similar therapies have been known to cause an initial rise in testosterone level prior to it declining. The initial upswing is the concern for it is counterproductive to the cancer therapy. Degarelix does not appear to entail this disadvantage.

The study on which the article reports indicates another advantage of degarelix namely, fewer urinary tract infections among patients participating in the study compared with another (leuprolide) group. Degarelix consequently may be substituted for the drug leuprolide in the near future. It looks as if degarelix reduces PSA levels and testosterone without the disadvantage of an initial testosterone surge.

A New Type of Pill

Intelligent pill doesn’t dissolve—it examines is the title of an article appearing at R&D. As the title indicates this is no ordinary pill. Rather than the contents dissolving and being absorbed by the body, this pill will pass through the digestive tract and during its passage release controlled amounts of drugs at predetermined locations. The pill has a pH sensor which enables a determination of where it is in the digestive tract. Different areas of the digestive tract have different levels of acidity. Acid levels are highest in the stomach but steadily decline as the pill navigates its way through the intestines.

The pill, developed by Philips Research and dubbed iPill, has a reservior capacity for storing drugs. It also has a fluid pump for dispensing the drugs and a microprocessor which directs the drug release process. Dosing can occur at multiple release points. In addition the iPill has a battery, temperature sensor and RF wireless transceiver. The temperature sensor gathers local temperature information and transmits it via its wireless transceiver to an external receiver unit.

Intelligent pills can also be used for diagnostic purposes. This can be accomplished with the inclusion of a miniature camara. When more precise imagery is required more conventional techniques like endoscopy, MRI and CT scans can supplement. The combination of site specific treatment and diagnostic capabilities offers new medical benefits that could help treat disorders like Crohn's disease, colitis and colon cancer.

A New Blood Test to Detect Breast Cancer

Biochemists Develop Proteomic Test For Breast Cancer is a Science Daily article about a blood test that could detect breast cancer at an earlier stage than a mammogram. The name of the test is the BC-SeraPro. The test measures protein concentration in blood and then compares the levels to what would be a normal condition. The test also has an advantage over mammograms in reduced false positives and false negatives. For mammograms false positives occur at a rate of about ten percent and false negatives at about twenty percent.

U.S. Health Care

Science Daily features an article titled American Values Blamed For U.S Health-care Crisis. The article cites information gathered from articles authored by Dr. Marc Nuwer which appear in the journal Neurology. The theme of the linked article is that Americans have to adjust their thinking for the good of our health care system. I was surprised to learn that we currently spend more than two trillion dollars a year on health care which is four times a much as we spend on national defense. This is predicted to go up to four trillion by 2015 which would make health care 20% of our GNP. It is already the largest sector of the economy. There is also this (quoting):

10 percent of U.S. expenses are spent on "defensive medicine" — pricey tests ordered by doctors afraid of missing anything, however unlikely. "Doctors don't want to be accused in court of a delayed diagnosis, so they bend over backwards to find something — even if it's a rare possibility — in order to cover themselves," Nuwer says.

Evaluating Strokes Through Comparative Effects on White and Gray Matter

Gray matter, a term used in conjunction with discussions of the brain, is familiar to most people. White matter much less so. But both gray and white matter are essential elements of brain tissue. Brain Atlas is instructive. Some good images are available at this site. Information about the brains of multiple species can be found.

Differences between Gray Matter and White Matter Water Diffusion in Stroke: Diffusion-Tensor MR Imaging in 12 Patients, from the journal Radiology, discusses results of an investigation "to determine if differences in water diffusion exist between white matter and gray matter in acute to early subacute human stroke." The authors of the paper are Pratik Mukherjee, MD, PhD, Mark M. Bahn, MD, PhD, Robert C. McKinstry, MD, PhD, Joshua S. Shimony, MD, PhD, Thomas S. Cull, PhD, Erbil Akbudak, PhD, Abraham Z. Snyder, MD, PhD and Thomas E. Conturo, MD, PhD. The researchers concluded that greater reduction in isotropic diffusion occurs in white matter as compared to gray matter in acute to early subacute middle cerebral arterial stroke.

Inhibiting HIV-1's Pathogenic Efffects

APOBEC3G Inhibits Elongation of HIV-1 Reverse Transcripts is a PLOS Pathogens paper authored by Kate N. Bishop, Mohit Verma, Eun-Young Kim, Steven M. Wolinsky and Michael H. Malim. The abstract:

APOBEC3G (A3G) is a host cytidine deaminase that, in the absence of Vif, restricts HIV-1 replication and reduces the amount of viral DNA that accumulates in cells. Initial studies determined that A3G induces extensive mutation of nascent HIV-1 cDNA during reverse transcription. It has been proposed that this triggers the degradation of the viral DNA, but there is now mounting evidence that this mechanism may not be correct. Here, we use a natural endogenous reverse transcriptase assay to show that, in cell-free virus particles, A3G is able to inhibit HIV-1 cDNA accumulation not only in the absence of hypermutation but also without the apparent need for any target cell factors. We find that although reverse transcription initiates in the presence of A3G, elongation of the cDNA product is impeded. These data support the model that A3G reduces HIV-1 cDNA levels by inhibiting synthesis rather than by inducing degradation.

Humans and other host organisms are able to draw on their own viral defense resources in order to inhibit the replication of the human immunodeficiency virus known as HIV-1. The question is how is this accomplished? Researchers focused on an enzyme dubbed APOBEC3G (A3G) to get answers. A3G belongs to a class of enzymes called deaminases which catalytically cause the removal of an amino group from a compound, generally by hydrolysis. But what strategy does A3G employ in inhibiting viral replication? Does it induce the degradation of viral DNA or does it inhibit synthesis. Researchers, authoring this paper, believe the latter occurs.

Replication of HIV-1 occurs through a process called reverse transcription. Retroviruses, including HIV-1, coopt host cell resources to enable their own viral functions. The replication of their own genome is accomplished with cellular assistance and a viral enzyme known as reverse transcriptase which makes reverse transcription possible. During the process an RNA viral genome is transcribed to complementary DNA (cDNA). The authors reveal in their paper their prior belief that viral cDNA would be stripped of uracil nucleotides by cellular enzymes called DNA glycosylases. Resulting abasic sites, sometimes referred to as hypermutation, would induce cleaving by cellular endonucleases causing subsequent degradation of cDNA. Yet the discovery that the inhibition of viral replication can take place in the absence of hypermutation led researchers to suspect that something more was afoot. They posed the logical question: what would account for cDNA degradation if not enzymatic editing?

The answer to the question appears to lie with a disruption of reverse transcription. Reverse transcription is multi-step process. A3G seems able to, at least, partially disrupt some steps thereby inhibiting viral replication. In the words of the authors:

Together with existing data, our results support the proposal that A3G inhibits the elongation of HIV-1 DNA by reverse transcriptase, probably by steric hindrance, rather than promoting the degradation of viral cDNA.