Saturday, March 5, 2011

Low Sperm Counts Linked to Fetal Effects

Scientists report being able to take the measure of a man — or at least his ability to father children — with a $40 pair of measuring calipers. They use the instrument to carefully assay the distance between his genitals and anus.

In a new study, this distance proved a potent predictor not only of sperm count but also of semen quality — the concentration of sperm as well as sperm motility and shape. Of these, sperm count correlated best with anogenital distance, or AGD. In fact, “AGD is now the strongest predictor of sperm count that we know of,” says Shanna Swan, a reproductive epidemiologist in the University of Rochester’s Department of Obstetrics and Gynecology.

No one knows what triggered the reproductive changes for which AGD serves as a marker, Swan says. A number of environmental factors — including a mother’s smoking or obesity — appear able to perturb fetal androgen levels. But in 2005, Swan’s group correlated a diminished AGD in infant boys with a small penis — and both appeared linked to elevated concentrations of chemicals known as phthalates in urine collected from the boys’ mothers during prenatal visits. Phthalates constitute a widely used family of chemicals that serve as solvents and that make certain plastics flexible. Studies show people throughout the industrial world are regularly exposed to them.

The share of reproductively challenged men that Swan’s team turned up in the new study was large. Based on semen measurements, one in four of the 126 apparently healthy men who were tested appeared subfertile at best — and possibly infertile, Swan and her colleagues report online March 4 in Environmental Health Perspectives. The men in this group had sperm concentrations at or below 20 million per milliliter, a cutoff that Swan says doctors often use to determine whether men who haven’t been able to father a child warrant referral to a fertility clinic.

Animal studies show that AGD is controlled early in prenatal development by sex hormones, especially androgens such as testosterone, notes Richard Sharpe of Queen’s Medical Research Institute in Edinburgh. “AGD therefore offers a lifelong readout of fetal androgen exposure — and just for this critical period of vulnerability,” which he says roughly corresponds to weeks eight through 14 of human gestation.

His group linked shortened AGD in rodents with reduced sperm counts, birth defects affecting the genitals and smaller male organs. But there remained the nagging question of whether AGD provided a similarly important readout of androgen exposure in early human development. 

“We now know it does,” Swan says.

The evidence emerged among residents of Rochester, N.Y., who took part in the first study of semen quality among healthy U.S. men. “These were kids in college,” Swan says. “They volunteered to be tested just because they wanted to make $75,” the compensation for participating.

Those whose anogenital distance was below the median for their build were 7.3 times as likely to be in the subfertile group as were those whose AGD was above the median, Swan says. Her team’s analyses found less than one-tenth of a percent likelihood that this association might be due to chance.

“Up until now, nobody has really understood what might be the impacts of a shortened AGD on quality of life,” says Philip Landrigan, director of the Children's Environmental Health Center at the Mount Sinai School of Medicine in New York City. “So this observation that a short AGD is correlated with low sperm count is new stuff and, I think, very important.” 

One reason: Getting useful measures of sperm is complicated because numbers fluctuate with a host of factors, including season, ambient temperature and how long a man has been abstinent. “The beauty of measuring AGD,” Landrigan says, “is that once it’s established [in the womb], it remains stable — as long as you adjust for the overall size of the man.” This gives doctors “a new way to screen men — a new tool in their quiver.” 

Data since 1992 have pointed to low and falling sperm counts among men throughout much of the developed world. “And we’ve been touting for years that this may have its origins in fetal life,” Sharpe says. “But we’ve lacked the direct evidence.” The new Rochester data, he says, now offer an explanation for low sperm counts in a large share of young men.

Sharpe’s team also has shown that fetal exposure to some phthalates can shorten AGD in rats and diminish their adult sperm production. The sperm changes traced back to a reduced proliferation of Sertoli cells in the fetal testes. “Ultimately,” he says, “the number of Sertoli cells will determine how many sperm you can make in adulthood.”

By: Janet Raloff

Alpha wave may affect sleep quality

Making waves isn’t conducive to staying asleep, at least when the waves are a type of brain signal associated with being awake.

A type of brain activity known as an alpha wave emanates from the back of the head when a person is awake but relaxing with eyes closed. Scientists used to think that the wave was subdued and disappeared as a person fell deeper and deeper into sleep.

But the alpha wave doesn’t disappear; it just goes undercover during sleep, researchers report online March 3 in PLoS One. The covert alpha wave may help determine how deeply people sleep and how much noise is needed to rouse a sleeper.

The finding “stresses that sleep is really a dynamic process,” says Mathias Basner, a sleep researcher at the University of Pennsylvania in Philadelphia who was not involved in the study. The study shows that sleep doesn’t happen just in discrete blocks, as most charts of sleep stages would indicate. Instead, brain activity changes from moment to moment during sleep. 

“It may suggest that something is going on in the central nervous system that we don’t know about and should maybe pay more attention to,” Basner says. 

Scientists hadn’t ignored alpha waves on purpose, says study coauthor Scott McKinney, a sleep scientist at Massachusetts General Hospital and Harvard University. Researchers typically measure brain activity during sleep with electroencephalographs, or EEGs, devices that use electrodes on the scalp to detect electrical activity in the brain. The squiggly lines recorded by the EEG can be hard to interpret with the naked eye, so McKinney and his colleagues used computer programs to break the EEG signals from 13 volunteers down into discrete waves. The analysis revealed that alpha waves never truly go away; they just get drowned out by more vigorous signals the way spreading ripples from a small rock dropped in a pond are swamped by waves from a passing speedboat. 

Alpha wave activity decreases as people enter ever-deeper levels of sleep and increases as people cycle back into more shallow sleep stages. In study participants, the ups and downs of alpha wave activity were closely associated with how easily a person could be awoken by traffic noises, loud talking or other sounds that might be encountered in hospital or at home in a city. When alpha wave activity spiked just before a noise was played, volunteers woke up more easily than when alpha wave activity was low, the researchers found. 

Alpha wave activity may be the brain’s way of keeping people aware of their surroundings during sleep, speculates Phyllis Zee, director of the Sleep Disorders Program at Northwestern University in Chicago. Such awareness enables people to wake quickly in case of danger, but too much alpha activity might also have a downside if it prevents a good night of sleep. 

People with insomnia commonly complain that they are very light sleepers and are always aware of their surroundings, Zee says. Although many insomniacs get a full night of sleep, they report that their sleep is not restful. But laboratory tests often don’t show any abnormalities.

“The classical way we’re scoring sleep may not give a good handle on what a patient really experiences,” she says. “This new way of analyzing depth of sleep may be used to get a better understanding of a patient’s complaint.”

By: Tina Hesman Saey

Thursday, February 10, 2011

Which Country Has the Tallest People?

Haha, this is a good one! Check it out!

Statistically, the tallest people in the world, as measured by country are the Dutch. The average height for all adults for the Netherlands is 6 feet 1 inch (1.85 m). This great leap in height is a huge change for Holland, where about 100 years ago, 25% of men who attempted to join the army were rejected as being too short, less than 62 inches (1.57 m) tall.

There are taller people belonging to certain populations within countries. This is especially true of the Maasai people, who live in parts of Tanzania and Kenya. But as a whole, the citizens living in the Netherlands are on average, the tallest people. Even people who have immigrated to the Netherlands from other parts of the world are taller on average than their racial groups in their countries of origin.

Standing next to the Dutch, almost shoulder to shoulder, are the Danes. Average height in Denmark is 6 feet (1.83 m). Americans, who once were the tallest people, have fallen in stature and are on average about 5 feet 9 inches (1.76 m) for men.

Researchers have attempted to account for what makes a certain country have the tallest people and conclude that factors for height include a combination of genetics and nutrition. The Dutch, several hundred years ago, were some of the tallest peoplein the world. Uneven distribution of wealth, poor nutrition, and years of bad crops certainly contributed to keeping the Dutchshorter for many years. From a genetic standpoint, though, the Dutch could have been the tallest people sooner with appropriate nutrition, especially during early childhood years.

Those who study these statistics suggest that the Dutch emphasis on early childhood care, a diet rich in dairy products and thus high in protein, and a fairly even distribution of wealth have contributed to making the Dutch the world’s tallest people. In contrast, in America, pockets of poverty, which contribute to poor childhood nutrition and lack of available healthcare, as well as immigration of shorter racial groups to America, have resulted in a shorter average height.

Being the tallest people in the world is not without disadvantage. In recent years, the Dutch have had to make changes to building codes order to provide taller doorframes, and more "height" friendly aspects to each new building and auto design. Further, the measurement is “average height” which means some people far exceed 6 feet 1 inch. Some people are significantly taller and may stand nearly 7 feet (2.13 m) tall, which can make traveling in the average car quite uncomfortable.

Wednesday, February 2, 2011

Stroke and heart attack symptoms in women

It’s easy to miss heart attack symptoms at the initial stages because symptoms show up differently in women than in men. In fact, the top four symptoms are often misdiagnosed. Immediate intervention can mean life or death, so it’s a good idea for all women to be aware of the warning signs of heart attacks.

Symptoms of heart attack in women

Most heart attacks start slowly with mild pain or discomfort. Here are the symptoms of heart attack in women:

  • Shortness of breath. May occur with or without chest discomfort.
  • Nausea and light-headedness
  • Flu-like symptoms, including chills and cold sweats
  • Heart palpitations
  • Chest discomfort (angina): pain, tightness or pressure in the center of the chest that lasts more than a few minutes, or that goes away and comes back
  • Discomfort in other areas, including pain or discomfort in: one or both arms (especially the left arm), the back, between the shoulder blades, neck, jaw or stomach
  • Heartburn or indigestion
  • Extreme fatigue

Symptoms of stroke in women

Strokes are not as common as heart attacks, but can come on without warning. Here are signs that a stroke may be occurring:

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the bod
  • Sudden confusion, trouble speaking or understanding
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking, dizziness, loss of balance or coordination
  • Sudden, severe headache with no known cause

It’s worth noting that in some women symptoms of heart problems, like palpitations, chills or faintness, may actually be symptoms of perimenopause. However, if you are experiencing these symptoms, you should see your healthcare practitioner.

Symptoms of inflammation

Heart disease often occurs along with inflammation. Monitoring any inflammation symptoms you might have is a helpful way to assess your risk of heart attack or stroke. Here are some of the symptoms to look for:

  • Elevated levels of CRP, homocysteine, or LDL
  • High blood pressure
  • Insulin resistance or diabetes
  • Joint pain or arthritis
  • Headaches
  • GI distress, bloating, constipation/diarrhea
  • Ulcer/heartburn
  • Food and other allergies/sensitivities
  • Chronic respiratory difficulties, asthma, or bronchitis
  • Dry, itchy skin, rash, psoriasis or eczema
  • Weight gain/obesity
  • Fever or chronic infection
  • Other autoimmune diseases

Tuesday, February 1, 2011

A Healthy Diet Can Prevent Some Cancers

Living a cancer-free life begins with keeping your plate full of color and including exercise as part of your daily routine.

The American Cancer Society estimates that one-third of all cancer deaths could be prevented if Americans ate a healthy, balanced diet that emphasized plant-based foods, participated in physical activity and maintained a healthy weight.

The following tips are not only good for your waistline, they’re also good for preventing many common types of cancers.

Eat a variety of fruits and vegetables.

They’re power-packed with vitamins, minerals and antioxidants. A diet rich in colorful fruits and vegetables has been linked to a decreased risk of bladder, colon, lung, mouth, throat, esophagus, pancreas, prostate and stomach cancers. The latest Dietary Guidelines for Americans recommend five to nine servings of fruits or vegetables daily.

Include fiber in your diet every day.

Fiber has been proven to reduce the risk of several cancers including colon cancer. The American Dietetic Association recommends 25 grams of fiber for women and 38 grams of fiber for men daily. Choose whole-wheat breads, pastas and cereals over their refined white-flour counterparts. Adding dried beans or lentils to your meals not only increases your fiber intake, they also add healthy calories and protein.

Choose lean meats such as fish or poultry.

A diet high in red meats or in processed meats such as bacon, sausage or hot dogs may increase your risk of colon cancer. Bake, broil or grill your lean meats rather than fry them. Add low-fat cheeses to meals to increase healthy calories and protein.

Drink at least eight cups of water a day.

Unsweetened tea and coffee are other options, and drinking green tea may reduce your risk of breast or prostate cancer. Low-fat milk is a great source of calcium and vitamin D. Avoid sugary drinks like soft drinks and juice cocktail. Drinks with 100 percent juice are a viable alternative but should be limited to one 8-ounce glass a day.

Get moving.

Adults should aim for 3½ to seven hours of moderate-intensity exercise every week. Any variety of physical activity counts as long as it increases your heart rate — this even includes common activities such as walking, stretching or yard work.

For more healthy eating tips for cancer patients as well as those wishing to reduce their cancer risk, check out the Markey Menu blog at UKHealthCare.uky.edu/MarkeyMenu.

Karina Christopher is a registered dietitian at UK Markey Cancer Center and runs the Markey Menu blog for UK HealthCare.

By Karina Christopher, registered dietitian at the UK Markey Cancer Center

Source: http://uknow.uky.edu/content/healthy-diet-can-prevent-some-cancers

Wednesday, January 26, 2011

Computational Science: A New Science Branch?

Raise your hand if you've never heard about computer science before. I bet no one. What about computational science? Have anyone heard about it before? Few, I believe.

As we know, computer science is a field that study theoretical and practical foundation of information and computation to be implemented in computer and computing systems. Computer scientist works in studying softwares and algorithms in create, describe, and transform the information, then applies it on the computer systems by build new softwares, improve the previous one, or even design a new system.

So, what about computational science? Computation itself needs theories and methods of computer science to process and analyze information. Generally, computation is used as a scientific method of certain research fields of science. This can be implied that the term 'computational science' refers to the scientific branch which solve the problem in science using a computational methods, which concerns to mathematical modelling, quantitative analysis and simulations.

There are several fields of science which broad its perspective using computational theories and methods. Some of the fields are physics, biology, chemistry, and material science. Other fields which also use it are linguistics and finance.

What is the basic skill of computational science? Sure, it's all on mathematics and programming! Anyone want to learn it has to face at least linear algebra, numerical analysis, and programming skills (the most popular maybe still on C language and FORTRAN). But it doesn't means that its object fields such as physics and biology get a cheesy part in the process. Anyone learning fields of computational science for biology, popularly called computational biology, have to understand basic principles of topic he/she want to analyze. For an example, if someone want to make a simulation of protein synthesis in cell, he/she has to understand the pathway of protein synthesis in the cell, without missing the detail of materials (enzymes, etc) and reactions needed. If that one is already understand about the basic knowledge, then he/she would be able to enter the computational process, like choosing what methods he/she can use and what kind of data is needed.

Hard!! Why on earth should this kind of science be invented and studied? Physics, finance, and other fields itself are already hard to learn. Quantum physics is already complex enough to learn, why should anyone want to model or make simulations of it? That's the point! There are a lot of science branches that are, in some reasons, hard to do an experiment on it. Either by the huge budget it needs or limited technology. Sure it's not cheap and easy to see an electron movement in a room filled with bananas (who wanna do that anyway!!).

Computational science is a really good way to support the real experiment and build a model or prediction based on experiment. It really works on many research topics of science in the last decade, and will grow more and more in line with the invention and development of computer technology, science theories, and the needs in other aspects, such as industrial needs for material design or business prediction trends for the next decade. Yeah, computational science is a broad-prospect field. But more than that, it gives huge contribution to the outgrowth and advancement of science. So, if you are currently learning science, math or related fields, wanna give a shot to take a part on it?

Tuesday, January 25, 2011

50 First Dates: Possible or Totally Fiction?

I wanna make you smile whenever you're sad
Carry you around when your arthritis is bad
All I wanna do is grow old with you

What's up, TnT's? Remember those lyrics? Read it again... Still don't remember? Okay, don't need to Google it cause I'll tell you now. It's from Adam Sandler's song titled "Grow Old with You". Now I bet you can answer, from what movie is that song? Yes! 50 First Dates (gosh! I already spoiled it on the post title!!). Let me refresh your memory.

Lucy (Drew Barrymore) had a car accident that makes her loss her memory overnight, means that she can remember all the things for the same day events, but will totally forget it after she wakes up in the morning. Harry (Adam Sandler) met her and fell in love. Knowing her condition, he tries every way to meet her everyday, which means that they will meet, acquaint, every morning. And then...

Stop the spoil!! I don't wanna be kicked by TnT's that hasn't seen the movie (where have you been?! Kidding). We've already got the point: Lucy's case. So, what is actually happened with Lucy?

The car accident Lucy got gave her an injury on her brain, called traumatic brain injury, happened caused by a hit on her head. The problem don't stop in that case cause she has got another scary things that can be forever: brain disorder. Remember Alzheimer, Parkinson disease, stroke, ADD/ADHD? In Lucy's case, she's got amnesia.

So, what kind of amnesia it that? It is called anterograde amnesia, which deals with Lucy's short-term memory. To remember something for weeks or years, the brain needs to recognize and convert the things that we just remember, such as this article that you read now, to a long-term memory. In Lucy's case, her brain fails to do that, makes her forget anything happened a day before. Scary? Yeah, totally.

Okay, that's the medical analysis. But in real life, is that possible? Well, actually, it seems yes. In 2010, researchers in UK found a woman that has a similar condition after got a car accident. She has a good memory for anything happen at the same day, but it lost overnight. The interesting fact, she claimed that she has never seen 50 First Dates (actually she has seen it several times), but she said that Drew Barrymore is her favorite actress. This leads to the speculation that the experience she has got from seeing the movie has been recorded unconsciously in her brain, just similar like what happens with Lucy and Henry's face painting (hmmm, I wanna write the story but decided to not spoiling it). Or maybe, that woman just seeing Charlie's Angels or Never Been Kissed several times years before. Might be.