Zark's

What's the Issue With Grapefruit Juice and Drugs?

Entomologists David Robacker (left) and Donald Thomas examine fallen grapefruit in an orchard.
Image Credit: Scott Bauer, USDA

Wikipedia explains that grapefruit juice is plentiful with vitamin C, but is also a potent inhibitor of the cytochrome P450 CYP3A4 enzyme.

Wikipedia further explains that cytochrome P450 CYP3A4 is the most important enzyme for metabolizing xenobiotics.  These are chemicals that are found in an organism that are not naturally there or part of its diet.  Say for example, a pharmaceutical drug that you are taking for some reason or another.  That would be a xenobiotic.

Grapefruit Juice and Medicine May Not Mix explains that CYP3A4 breaks down xenobiotics such as drugs in the small intestine.  But grapefruit juice inhibits the metabolism of the drug, so it stays in the bloodstream longer than it should.  Drugs that are particularly dangerous with grapefruit juice in your body include statins such as Lipitor and blood-pressure lowering drugs such as Nifediac. People have differing levels of CYP3A4 in their small intestine, so it is difficult to predict an individual's reaction to the mixing of grapefruit juice and a drug.

Not mentioned by the FDA, but cautioned by Wikipedia include drugs such as oxycodone. 

Curiously there are other drugs affected by grapefruit juice that have an opposite reaction - the juice retards absorption of the drug.  For example, Allegra is not absorbed by the body due to grapefruit juice blocking the transport of the drug instead affecting metabolism.

The FDA recommends that you specifically ask your doctor or pharmacist about interactions with any fruit juices in your diet and your medication.  The FDA requires this information when a company applies for approval of a new medicine.

 

 

Flu Variant Sighted

Image Credit: CDC

It has been a warm winter for the U.S., and as you might expect, we have not experienced the outbreak of influenza that we incur when everyone is kept indoors.  But the latest survey shows increased infection rates, particularly in California and Colorado. 

So far, the infections appear to be 94 percent Influenza A with Influenza B as the remainder.  Of the former, H3 is almost 46 percent and the 2009 H1N1 is almost 14 percent of the Influenza A infections.  Also notable is that of all the specimens tested by CDC, all can be controlled by the anti-viral drugs oseltamivir and zanamivir.

The CDC has also published that evidence of H3N2v, a variant of swine flu has surfaced.  Usually swine flu does not cross over into humans, but when it does, a 'v' is suffixed to indicate the virus is a variant.  Again, usually, the primary source of infection is to humans around an infected animal.  Person-to-person spreading can occur, and the CDC is watching for evidence of this transmission. 

H3N2v infections have been observed in U.S. swine herds, but the extent of infection is unknown.  Initial serum tests suggest that adults have some pre-existing immunity to the virus, but children do not.  The number of cases is extremely small, but the CDC is again watching for spreading of this novel virus.

 

 

 

 

 

 

Virus Killing Thousands of Lambs in the UK

Image Credit: USDA

The Schmallenberg virus is an orthobunyavirus that can cause fetal congenital defects and stillbirths in cattle, sheep, and goats.  It was first reported in November 2011, so researchers are still learning about the virus.  It appears to be transmitted by midges. 

Okay - I didn't know what a midge was either.  It is a small two-winged fly and many of the pests are known disease carriers.

The name for the new virus comes from the city in Germany where the first identified case was observed.  It does not appear to be zoonotic - or able to infect humans.

Mystery virus kills thousands of lambs tells that lambs can be born with such terrible deformities they cannot survive.  The Telegraph article explains 74 farms across southern and eastern England have become victim to the virus.  The disease is sneaky because the extent is known only when the sheep and cows give birth.  Of the farms suffering from the disease, losses range from 10 to 20 percent of the births. 

Cows have a longer gestation period, so in a few months, we have a crisis for cattle as well.  Because farmers are not legally required to report infection, the actual number of animals infected could be much greater than preliminary data suggests.  Speculation is still upon the midges, and it is is unknown whether animal-to-animal transmission is possible. 

The CDC describes the disease in their Emerging Infectious Diseases journal.  So far the dairy cattle have been exhibiting various symptoms of disease, including decreased milk production.  The CDC is still labeling the risk to humans as very low to negligible, but cautions surveillance should be maintained in the regions with infected animals.

 

How Much Shale Oil and Gas is on Alaska's North Slope?

North front of Brooks Range along southern margin of central North Slope assessment area
Image Credit: USGS

It is a bit confusing.  Shale oil is petroleum that has not migrated from the source rocks.  Oil shale is a rock that had not yet generated petroleum, but can produce oil if artificially heated.  Conventional oil and gas resources migrate from the source rocks, but shale oil and shale gas remain trapped in the originating source rock.

Prudhoe Bay oil field in Alaska is the largest oil field in North America, almost 334 square miles in size.  Over 11 billion barrels of oil have been extracted from the field.  The petroleum found in Prudoe Bay migrated from the original source rocks on the North Slope.  A thought tantalyzing many an oilman is how much petroleum remains in those source rocks.  These rocks occur at depts ranging from less than 3,000 feet along the northern coast to 20,000 feet in the Brooks Range foothills.  (How is something 4 miles high only a footheel?) Oil is primarily in the north and gas in the south.

As shown in the graphic below, they analyzed three source rocks: (1) The Triassic Shublik Formation, (2) the lower part of the Jurassic–Lower Cretaceous Kingak Shale, and (3) the Cretaceous pebble shale unit and Hue Shale. 

USGS estimates between zero and 2 billion barrels of oil remaining in the source rocks.  They also estimate betwwen zero to 80 trillion cubic feet of gas.  Sheesh - that sounds like hedging their bets, doesn't it?

 

 

 

 

Suffered a Stomach Bug this Year?

Transmission electron micrograph of the genus Norovirus, and the family Caliciviridae. They are a group of related, single-stranded RNA, nonenveloped viruses that cause acute gastroenteritis in humans.
Image Credit: CDC/ Charles D. Humphrey

Nasty, contagious norovirus is 'everywhere' now explains that one in fifteen Americans suffered an unpleasant stomach bug in the last year.  Although we describe most politely as the stomach flu, it is really a norovirus infection. 

Wikipedia reminds us that a norovirus is an RNA virus, which incidentally is responsible for 90 percent of the world's nonbacterial suffering of gastroenteritis.  Noroviruses are easily transmitted from person to person and only one to ten virus particles are necessary to infect the victim.  The infection begins in the small intestine and within one to two days, the stomach flu symptoms are present for up to 60 hours. 

In case you are fuzzy about RNA viruses, they can have one or two RNA strands. These are different from the larger class of viruses, those that have DNA as genetic material.  Some of the strains that result in gastroenteritis include the Norwalk, Hawaii, and Snow Mountain.  They have carbohydrate binding receptors which allows them to attach to food molecules.  Researchers are working on vaccines, but nothing is available yet.  Also, because the virus mutates rapidly, annual boosters will be required.

The CDC has a norovirus website with some tips on avoiding the infection and what to expect if you catch it.  As you probably know from experience, you don't obtain an immunity to the virus.  Because of the vomiting and diarrhea, dehydration can be a medical problem. 

Their suggestions on preventing the spread of norovirus: a) wash your hands (interestingly, the CDC says that alcohol-based hand sanitizers are not as good as washing with soap and water) b) proper hygiene in the kitchen, and don't prepare food if you are infected, c) clean and disinfect contaminated surfaces, and d) wash laundry throroughly.

Relax - Einstein was Right

In this bubble chamber track, a neutrino passes close to a nucleon and reemerges as a neutrino.
Image Credit: CERN

In November, I had blogged, Researchers Still Believe Neutrino Faster Than Light, describing how researchers were puzzled their calculations showed neutrinos traveling faster than light.  In their experiment, they fire neutrinos from CERN in Geneva to a laboratory in Italy.

Dear CERN: Always Check the Cable Before Doubting Einstein explains there was a loose fiber optic cable connection to a GPS receiver.

Faster-than-light neutrino measurement has two possible errors adds that the measurements had neutrinos arriving at the Gan Sasso National Laboratory 60 nanoseconds faster than light.  But not only was there a loose fiber optic connection, but the interpolation of time at an atomic clock may have been in error as well. 

Mmm.  The science writers have someone to poke fun at, and they are enjoying it.  It is too bad though, because the world would be a lot more interesting if we could send pulses faster than light.  However, I am fond of causality, which faster-than-light would defeat. 

Two days ago I had written about a diet pill.  The ultimate diet pill though, might involve the Higgs particle.  Unless matter interacts with the Higgs field, it does not possess mass.  Maybe we can somehow alter the Higgs field around us so that we can reduce our weight.

 

NASA Generates Global Tree Height Map

Global map of forest height produced by NASA's ICESAT/GLAS, MODIS, and TRMM sensors.
Image credit: NASA/JPL-Caltech

NASA satellites pinged the surface of the Earth with 2.5 million carefully positioned laser pulses to measure the height of the world's forests.  The map above shows the peak height of the canopy with a spatial resolution of 0.6 miles. 

The tropics as you might expect, have a high canopy height with large areas of red for South America, south-central Africa, Indonesia, and Papua New Guinea.  (Perhaps California redwoods are also appearing red.)  Note the deserts of Africa and Australia have an absence of trees.

NASA scientists hope the map will assist in estimating the carbon sinks formed by the forests.  It will also be a valuable record for measuring climate change.

 

Trial Drug MRK003 Shows Promise Against Pancreatic Cancer

Human tumor cells from the pancreas stained with an immunocytochemical stain with methyl green in the background and magnified to 400x.
Image Credit: Dr. Lance Liotta Laboratory, National Cancer Institute

The pancreas functions as both a digestive and endrocrine system.  It produces digestive enzymes that assists absorption of nutrients and digestion in the small intestine.  For the endocrine system, it produces several hormones including insulin, and glucagon. 

The National Cancer Institute estimates 43,920 new cases of pancreatic cancer in the United States for 2012.  Sadly, it also estimates 37,390 deaths.  The risk factors are: smoking (the largest risk factor), diabetes, family history, previous episode(s) of pancreatitis, and obesity. 

Pancreatic cancer: Trial drug MRK003 shows promise explains chemotherapy agent gemcitabine combined with MRK003 has been successful in killing cancer cells in mice.  They are currently testing about 60 patients in a clinical trial. 

Notch receptors are transmembrane receptors that help determine whether a cell continues reproducing, living, or even self-destructs.  There are four members of the Notch family that have been implicated with cancer.  Many cancers appear to depend upon Notch signaling survive.  MRK-003 is a γ-secretase inhibitor that can suppress this signaling.

Let's hope we have found a powerful weapon against this deadly cancer!

 

FDA Scrutinizes QNEXA

QNEXA
Image Credit: Vivus

In their advisory committee briefing, pharmaceutical company Vivus describes QNEXA as a one-a-day diet pill that contains immediate release phentermine hydrochloride (PHEN) and extended release topiramate.  The concept is to combine two types of weight control therapy - decreased hunger and increased satiety.  From a previous evaluation, the FDA expressed concern about potential birth defects and cardiovascular events.  After evaluation, the company agreed to remove the applicability of the drug for women of child bearing age.  (Basically any risk is unacceptable to that group is unacceptable.)

Vivus explains it believes the benefits of the new diet pill substantially outweigh the risks of obesity.  Their report explains the relative risk of diabetes increases 42 times in men and 93 times when the body mass index increases from normal to obese.  Their argument is that health care providers need another weapon in controlling obesity and QNEXA should be approved to be included in possible therapies.

U.S. to Review Diet Treatment Once Rejected tells that although the pill was rejected in 2010, docs have been prescribing the two ingredients independently, achieving the same thing. Perhaps as much as 70 percent of docs treating obesity.  Draft Questions for the February 22, 2012 Meeting of the Endocrinologic and Metabolic Drugs Advisory Committee give some hints on what the FDA is thinking.  They are concerned about cleft lip defects and cardiovascular impacts.  The panel of doctors will make a recommendation on whether the new diet pill should be approved and then the FDA will make a final determination in April.

If you are interested, The National Institutes of Healthy has chart to help you determine whether you fall into the Overweight or Obesity category.  They explain the primary cause is a lack of energy balance - you are consuming too many calories for the amount of calories your body is burning.  There are other factors - inactive life style, environment (work schedules, access to healthy food), genes and family history, and health conditions, among others.

Latest News on Colony Collapse Disorder

Honey bee on an apple blossom Image Credit: Jack Dykinga, USDA

 It became front-page news in the winter of 2006-2007.  Bee keepers suffered unprecedented losses of colonies, with the puzzling symptom of honey in the hive, normal levels of immature bees, but the worker bees had just disappeared.  It was serious - individual bee keepers lost between 30 and 90 percent of their hives.

No smoking gun for colony collapse disorder describes the absence of a cure.  Bees are incredibly sensitive biological marvels.  Researchers have discovered Varroa mites, Israel acute paralysis virus, malnutrition, and insecticide poisoning. All of these individually can affect the health of the bee population.  Also, in 2005, there was a large importation of Australian honeybees.  Together, do they create a perfect storm? We just don't know.

Premising that colony collapse disorder is a perfect storm, a company named BeesFree has developed a drinking solution for the bees that mixes antimicrobial agents, nutrients, and anti-oxidants. 

 Bees are important for many agricultural crops.  California's almond crop requires 1.3 million colonies, roughly 1/2 the colonies within the United States.  The beekeepers must move them soon after pollination, because the region returns to desert, with no food for the little bees.  A popular destination is North Dakota, where unfarmed fields blossom with flowers.

Historically, bees have disappeared before, such as the 1880s, 1920s, and 1960s.  Unfortunately there is little documentary data to help us understand whether the phenomena were similar, or if we have something brand new.

So what can you do to help?  Use insecticides sparingly and plant good nectar sources.