Friday, October 31, 2008
Treasures of the Sea products
Treasures of the Sea Yield Some Medical Answers and Hint at Others
by John Henkel
Don Hochstein raises a thin glass tube up to his eye level and flicks it with a fingernail. Inside the pencil-width vessel, a substance with the texture of gelatin shimmies and wobbles but doesn't move from the tube's bottom.
"There's endotoxin in there, you can bet on it," he says, slipping the tube back into a rack.
Hochstein, former deputy director of product quality control (he retired last Sept. 3) in the Food and Drug Administration's Center for Biologics Evaluation and Research, is demonstrating a simple analytical test. It's one that medical professionals, drug companies, pharmacies, and others use worldwide to detect the presence of endotoxins--dangerous toxic byproducts of "gram-negative" bacteria such as Salmonella and E. coli.
The test is the limulus amebocyte lysate assay and is, Hochstein says, "remarkable" for its origin: the horseshoe crab. The limulus test, along with an osteoporosis treatment derived from salmon and a bone filler made from coral, are approved medical products that come from the sea.
Until recently, virtually all medical products had terrestrial sources. For example, organisms found in soil have yielded products such as penicillin, amoxicillin, and other antibiotic compounds responsible for saving millions of Americans from suffering and death.
Sea-based products are rare, but some experts say the world's oceans and waterways may harbor the next generation of drugs, biologics, and even a few medical devices. Dozens of promising products, including a cancer therapy made from algae and a painkiller taken from snails, are in development at research laboratories right now. Other products, such as an anti-inflammatory drug extracted from an organism called the Caribbean sea whip, are under FDA review. Three approved products already have brought the healing power of the sea successfully into the world of public health.
Fat loss versus muscle loss
It is important to understand the difference between weight loss and fat loss. Weight loss typically involves the loss of fat, water and muscle. A dieter can lose weight without losing much fat. Ideally, overweight people should seek to lose fat and preserve muscle, since muscle burns more calories than fat. Generally, the more muscle mass one has, the higher one's metabolism is, resulting in more calories being burned, even at rest. Since muscles are more dense than fat, muscle loss results in little loss of physical bulk compared with fat loss. To determine whether weight loss is due to fat, various methods of measuring body fat percentage have been developed.
Muscle loss during weight loss can be restricted by regularly lifting weights (or doing push-ups and other strength-oriented calisthenics) and by maintaining sufficient protein intake. According to the National Academy of Sciences, the Dietary Reference Intake for protein is "0.8 grams per kilogram of body weight for adults."
Those on low-carbohydrate diets, and those doing particularly strenuous exercise, may wish to increase their protein intake. However, there may be risks involved. According to the American Heart Association, excessive protein intake may cause liver and kidney problems and may be a risk factor for heart disease [1]. There is no conclusive evidence that moderately high protein diets in healthy individuals are dangerous, however. It has only been shown that these diets are dangerous in individuals who already have kidney and liver problems.
How the body gets rid of fat?
All body processes require energy to run properly. When the body is expending more energy than it is taking in (e.g. when exercising), body cells rely on internally stored energy sources, like complex carbohydrates and fats, for energy. The first source the body turns to is glycogen, which is a complex carbohydrate created by the body.
When that source is nearly depleted, the body begins lipolysis, the metabolism of fat for energy. In this process, fats, obtained from fat cells, are broken down into glycerol and fatty acids, which can be used to make energy. The primary by-products of metabolism are carbon dioxide and water; carbon dioxide is expelled through the respiratory system.
Fats are also secreted by the sebaceous glands (in the skin).
Thursday, October 30, 2008
ultrasonography
What is ultrasonography?
Ultrasonography is body imaging using ultrasound in medical diagnosis. A skilled ultrasound technician is able to see inside the body using ultrasonography to answer questions that may be asked by the medical practitioner caring for the patient. Usually, a radiologist will oversee the ultrasound test and report on the results, but other types of physicians may use ultrasound as a diagnostic tool. For example, obstetricians use ultrasound to assess the fetus during pregnancy. Surgeons and emergency physicians use ultrasound at the bedside to assess abdominal pain or other concerns.
A transducer, or probe, is used to project and receive the sound waves and the return signals. A gel is wiped onto the patient's skin so that the sound waves are not distorted as they cross through the skin. Using their understanding of human anatomy and the machine, the technician can evaluate specific structures and try to answer the question asked by the patient's physician. This may take a fair amount of time and require the probe to be repositioned and pointed in different directions. As well, the technician may need to vary the amount of pressure used to push the probe into the skin. The goal will be to "paint" a shadow picture of the inner organ that the health care practitioner has asked to be visualized.
The physics of sound can place limits on the test. The quality of the picture depends on many factors.
- Sound waves cannot penetrate deeply, and an obese patient may be imaged poorly.
- Ultrasound does poorly when gas is present between the probe and the target organ. Should the intestine be distended with bowel gas, organs behind it may not be easily seen. Similarly, ultrasound works poorly in the chest, where the lungs are filled with air.
- Ultrasound does not penetrate bone easily.
- The accuracy of the test is very much operator dependent. This means that the key to a good test is the ultrasound technician.
ultrasound
What is an ultrasound?
Ultrasound produces sound waves that are beamed into the body causing return echoes that are recorded to "visualize" structures beneath the skin. The ability to measure different echoes reflected from a variety of tissues allows a shadow picture to be constructed. The technology is especially accurate at seeing the interface between solid and fluid filled spaces. These are actually the same principles that allow SONAR on boats to see the bottom of the ocean.
Brain Cancer Symptoms: Headaches and Seizures
Most people seek medical care to make certain that nothing bad is happening in their body. They seek reassurance from their doctor that all is well. Unasked questions that linger fill patients and their families with dread until their concerns are addressed.
"Is my abdominal pain due to appendicitis?"
"Am I having a heart attack?"
And the 800 pound gorilla in the room: "Is there 'something really bad' causing my headache?"
For golf legend Seve Ballesteros, there is something bad happening in his body. Two weeks ago, he experienced a grand mal seizure for the first time. As part of the evaluation of a new onset seizure, a CT scan of his brain was done and revealed a large tumor. It is amazing that significant parts of the brain can be destroyed and yet the patient can have normal function. Looking back, though, friends had reported that Mr. Ballesteros had been complaining of headaches, and perhaps he had had a few episodes of unusual or erratic behavior. Often the clues are recognized after the fact and can help explain previous events.
Seizures are relatively common in children and younger adults, and some may be due to an area of the brain that has an abnormal wiring pattern that can cause electrical surges. This can spread to the whole brain and make brain cells fire randomly all at one. This causes the jerking and stiffening motions of the body that we describe as a seizure. The brain doesn't like the irritation, and like a computer, logs itself off and then reboots. During this time, the brain doesn't take in new input and the patient can be sleepy and less than normally responsive. After a period of time, the brain returns its function to normal, and the patient returns to normal as well.
When an underlying problem is found, though, it needs to be addressed. While a CT scan can identify that a tumor is present, it can't say what type of tumor it might be. Tissue samples must be obtained to help make the diagnosis and plan treatment. Since the brain isn't the most accessible organ, a neurosurgeon is needed to open the skull and biopsy the tumor. At the same time, it may be necessary to cut away parts of the tumor (debulk) to prevent increased pressure on the remaining normal brain.
This is what happened to Mr. Ballesteros, and that led to two more bad things. The first is that because the normal brain tissue started to swell after the operation, another surgery was needed to remove more of the skull to allow that swelling to happen. The second bad thing was the diagnosis. The tumor was malignant, a cancer called an oligoastrocytoma, which arises from glial cells (support cell within the brain) that can be rapidly growing.
Treatment options include further surgery to cut away tumor. Because the tumor grows into areas of the brain that have vital functions, it is often impossible to remove all of it, and radiation therapy is required to help shrink and control the size of the remaining tumor.
Survival rates depend upon many factors, including how aggressive the tumor acts and how quickly it grows, the age of the patient, and any underlying medical problems. Mr. Ballesteros has many hurdles to face. He has already had two brain operations and is now undergoing a third within two weeks. Time will determine whether his brain can recover enough to tolerate radiation therapy. And then there is the question of function. While medicine can keep people alive, the goal is much loftier. The brain needs to be able to return to normal function so that the patient can enjoy life.
It is never good to be an interesting patient. Much of medical practice deals with routine complaints, and tests are performed to make certain that serious conditions are not present. The reason to perform those tests lies in the fact that some people do have bad things. It's tragedy that the odds didn't favor Mr. Ballesteros. After years of facing and conquering challenges in the golfing world, he now faces an opponent far more ominous than he did on the field of play. Hopefully, he has the ability to win one more round.
The Truth Behind 10 Diet Myths
Does Eating at Night Make You Fat? Is Caffeine Bad for You? Get the Facts on These and Other Diet
Meet the diet myth busters:
- Christine Rosenbloom, PhD, RD, CSSD, of Georgia State University in Atlanta
- Roberta Duyff, MS, RD, FADA, CFCS, the St. Louis-based author of the American Dietetic Association Complete Food and Nutrition Guide.
Here are 10 diet myths Rosenbloom shattered at the conference, and Duyff's tips on telling diet fact from diet fiction.
Myth: Eating at night makes you fat.
Reality: Calories count, whenever you eat them.
There's no proof for this myth, Rosenbloom says. She notes some small studies with mixed results, tests on animals, and a belief that because eating breakfast is linked to lower BMI, eating at night isn't as good. But all in all, Rosenbloom says, it's your calorie total that matters, day or night.
Myth: Avoid foods with a high glycemic index.
Reality: You could use the glycemic index to adjust your food choices, but don't make it your sole strategy for losing weight or controlling blood sugar, Rosenbloom says.
"For those people that are already counting carbs, this can be a way for them to fine-tune their food choices, but it isn't the be-all, end-all for weight loss," she says.
Myth: High fructose corn syrup causes weight gain.
Reality: "There's probably nothing particularly evil about high fructose corn syrup, compared to regular old sugar," Rosenbloom says.
She explains that this diet myth arose in 2003, when researchers noticed that obesity was rising along with the use of high fructose corn syrup. "They speculated that ... maybe we handle [high fructose corn syrup] differently than we do sugar," but "there really isn't any evidence to support that," she says.
The American Medical Association recently concluded that high fructose corn syrup doesn't contribute to obesity beyond its calories.
Myth: Caffeine is unhealthy.
Reality: Rosenbloom says there is some evidence that caffeine may have a positive effect on some diseases, including gout and Parkinson's disease, besides caffeine's famous alertness buzz.
Also, caffeine doesn't dehydrate people who consume it regularly, Rosenbloom says.
But she cautions that caffeine isn't always listed on product labels, and children who drink a lot of caffeinated energy drinks may get more caffeine than their parents expect. "Kids tend to guzzle these things, whereas an adult may sip a beverage," Rosenbloom says.
Myth: The less fat you eat, the better.
Reality: "For some people, counting fat grams can work for weight control, but it isn't the be-all end-all for people," Rosenbloom says.
She says that people with heart disease, diabetes, and metabolic syndrome may benefit from adding a little healthy fat -- the monounsaturated kind -- and cutting back on carbohydrates. But they shouldn't increase their overall fat intake -- just swap saturated fat for monounsaturated fat.
"If you go out to an Italian restaurant and you have triple cheese-meat-sausage lasagna but then you have a little olive oil on your bread, you're not doing much for your heart," Rosenbloom says.
Myth: To eat less sodium, avoid salty-tasting foods and use sea salt in place of table salt.
Reality: Your sense of taste doesn't always notice sodium, and sea salt or other gourmet salts aren't healthier than table salt.
"Just because it doesn't taste salty doesn't mean that it isn't salty," Rosenbloom says. She says many processed foods contain a lot of sodium -- check the label.
Sea salt, Rosenbloom says, contains slightly less sodium per teaspoon than table salt only because sea salt is coarser, so fewer grains fit into the teaspoon.
Myth: Drinking more water daily will help you lose weight.
Reality: There's no evidence that water peels off pounds.
Foods containing water -- such as soup -- can fill you up, "but just drinking water alone doesn't have the same impact," Rosenbloom says. "Our thirst mechanism and our hunger mechanism are two different things."
Myth: Whole grains are always healthier than refined grains.
Reality: Whole grains are a healthy choice, but you needn't ditch refined grains. "You can have some of each," Rosenbloom says.
The U.S. Department of Agriculture's "My Pyramid" dietary guidelines recommend getting at least half of your grain servings from whole grains.
"It doesn't say you have to replace all of your breads with whole grains or all of your foods with whole grains," Rosenbloom says. She adds that enriched grains -- refined grains with certain nutrients added (such as wheat enriched with folic acid, an important nutrient for preventing neural tube birth defects) -- have some perks.
"Enriched grains generally are going to have more folate, thiamin, riboflavin, niacin, and iron. The whole grains usually have more fiber, vitamin e, selenium, zinc, potassium -- so there's kind of a trade-off," Rosenbloom says.
Myth: Sugar causes behavioral problems in kids.
Reality: You might want to check your expectations about sugar and children's behavior.
For most children, "the excitement that kids have when supposedly they eat sugar is probably more related to the event and the excitement of the event than it is to actually consuming sugar," Rosenbloom says.
She cites research showing that when parents think their kids have been given sugar, they rate the children's behavior as more hyperactive -- even when no sugar is eaten.
Myth: Protein is the most important nutrient for athletes.
Reality: "It is true that athletes need more protein than sedentary people. They just don't need as much as they think. And they probably don't need it from supplements; they're probably getting plenty in their food," Rosenbloom says.
But timing matters. Rosenbloom recommends that after weight training, athletes consume a little bit of protein -- about 8 grams, the amount in a small carton of low-fat chocolate milk -- to help their muscles rebuild.
"That's probably all you need," she says. "You don't need four scoops of whey powder to get that amount of protein."
How to Spot a Diet Myth
New diet myths can crop up at any time; fads come and go. To Duyff, the task of telling nutrition myth from reality boils down to this: Step back, check out the evidence, and be a bit skeptical. Here is Duyff's specific advice:
- Look for red flags, such as promises that sound too good to be true or dramatic statements refuted by reputable health organizations.
- Think critically. Consider the "facts" touted in diet myths. Are they from biased or preliminary research? "One study doesn't make a fact," Duyff says. "The messages need to be evidence-based," which means multiple studies conducted in large groups of people and reviewed by independent scientists.
- Ask an expert. A registered dietitian or other health professional can help you tell nutritional fact from fiction.
- Remember, there are no magic bullets. "The true approach to good health includes an overall healthy eating pattern, enjoyed and followed over time," Duyff says.
10 Lifestyle Tips for Cancer Prevention
- Be as lean as possible without becoming underweight.
- Be physically active for at least 30 minutes every day.
- Avoid sugary drinks, and limit consumption of high-calorie foods, especially those low in fiber and rich in fat or added sugar.
- Eat more of a variety of vegetables, fruits, whole grains, and legumes (such as beans).
- Limit consumption of red meats (including beef, pork, and lamb) and avoid processed meats.
- If you drink alcohol, limit your daily intake to two drinks for men and one drink for women.
- Limit consumption of salty foods and food processed with salt (sodium).
- Don't use supplements to try to protect against cancer.
- It's best for mothers to exclusively breastfeed their babies for up to six months and then add other liquids and foods.
- After treatment, cancer survivors should follow the recommendations for cancer prevention.
Why These Cancer Recommendations?
Walter Willett, MD, DrPH, an epidemiology professor who leads the nutrition department the Harvard School of Public Health, was on the international team of scientists that wrote the recommendations.
At the ADA meeting, Willett said the first recommendation -- to be as lean as possible within the healthy weight range -- is "the most important, by far."
But there is one recommendation that Willett says may be a "mistake" -- the one about not taking supplements. Vitamin D supplements may lower risk of colorectal cancer and perhaps other cancers, notes Willett. He predicts that that recommendation will be a top priority for review.
How to Follow the Recommendations
Karen Collins, MS, RD, CDN, is the nutritional advisor for the American Institute for Cancer Research. She reviewed the recommendations before they were issued last year, and she joined Willett in talking to ADA members.
Collins provides these tips for each of the recommendations:
- Be as lean as possible without becoming underweight: Don't just look at the scale; check your waist measurement as a crude measurement of your abdominal fat, Collins says. She recommends that men's waists be no larger than 37 inches and women's waists be 31.5 inches or less.
- Be physically active for at least 30 minutes every day: You can break that into 10- to 15-minute blocks, and even more activity may be better, notes Collins.
- Avoid sugary drinks and limit consumption of energy-dense foods: It's not that those foods directly cause cancer, but they could blow your calorie budget if you often overindulge, notes Collins, who suggests filling up on fruits, vegetables, and whole grains.
- Eat more of a variety of vegetables, fruits, whole grains, and legumes such as beans: Go for a variety of colors (like deep greens of spinach, deep blues of blueberries, whites of onions and garlic, and so on). Most Americans, says Collins, are stuck in a rut of eating the same three vegetables over and over.
- If consumed at all, limit alcoholic drinks to two for men and one for women per day: Watch your portion size; drinks are often poured liberally, notes Collins. Willett adds that the pros and cons of moderate drinking is something that women may particularly need to consider, weighing the heart benefits and increased breast cancer risk from drinking.
- Limit red meats (beef, pork, lamb) and avoid processed meats: Limit red meats to 18 ounces per week, says Collins, who suggests using chicken, seafood, or legumes in place of red meat. Collins isn't saying to never eat red meat, just do so in moderation.
- Limit consumption of salty foods and foods processed with sodium: Don't go over 2,400 milligrams per day, and use herbs and spices instead, says Collins. She adds that processed foods account for most sodium intake nowadays -- not salt you add when cooking or eating.
- Don't use supplements to protect against cancer: It's not that supplements are bad -- they may be "valuable" apart from cancer prevention, but there isn't evidence that they protect against cancer, except for vitamin D, says Collins.
- It's best for mothers to breastfeed babies exclusively for up to six months and then add other foods and liquids: Hospitals could encourage this more, Collins says.
- After treatment, cancer survivors should follow the recommendations for cancer prevention. Survivors include people undergoing cancer treatment, as well as people who have finished their cancer treatment.
Making Cancer Prevention Simpler
Overwhelmed? Collins boiled the 10 recommendations down to these three:
- Choose mostly plant foods. Limit red meat and avoid processed meat.
- Be physically active every day in any way for 30 minutes or more.
- Aim to be a healthy weight throughout life.
Keep in mind that these tips are about reducing -- but not eliminating -- cancer risk. Many factors, including genes and environmental factors, affect cancer risk; diet and exercise aren't the whole story, but they're within your power to change.