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2011年3月31日星期四

Zezima: 'Jest what the doctor ordered'

You have to have the patience of a saint to deal with a devil of a patient.

That's what I learned recently when I went to the hospital for a ureteroscopy, a surgical procedure taken from the Greek words "ureter" (an extremely sensitive area of the lower anatomy) and "oscopy" (invaded by a scope the length of a boa constrictor).

The intention was to blast to smithereens a kidney stone that, because it appeared to be composed of concrete and asphalt, was barely dented by shock waves in a less invasive but unsuccessful procedure a few weeks earlier.

Despite the persistent fear that I would wake up as the lead singer for the Vienna Boys' Choir, I was in a pretty jaunty mood as I sat in the pre-op unit with my wife, Sue, who was at my side to provide comfort, support and, if necessary, information about my living will.

"Are you diabetic?" asked Janice, a nursing assistant.

"No," I replied. "I'm Italian." Janice laughed.

"It gets worse," Sue promised.

Sure enough, when Janice asked if she could take my blood pressure on my left arm, I said, "Either arm is fine. I have it narrowed down to two. Good thing I'm not an octopus or we'd have to do this underwater." "Is he always like this?" Janice asked Sue.

"Yes," Sue responded. "I just ignore him." I helpfully pointed out that I hadn't even been given drugs.

"If I gave you sodium pentothal, you'd be gabbing up a storm," Janice said.

"Please," Sue begged, "not that." "Do I have a pulse?" I asked Janice.

"Yes," she said. "It's 64. And your oxygen level is 100 percent." "I never got 100 on any test in school," I said.

"You just aced oxygen saturation," Janice replied.

"Too bad the oxygen isn't going to my brain," I noted.

Sue nodded.

Mary, a nurse, came in to continue the prep work.

"Turn toward me," she said.

"I'm taking a turn for the nurse," I told Sue.

Mary looked at Sue and said, "You're his daughter, right?" Sue chuckled. Mary smiled and said to me, "I'm giving it right back to you." She was just what the doctor ordered: nice, funny and very good at her job.

Then the doctor (or one of them) came in.

"I'm Dr. David Paul, your anesthesiologist," he said.

"What's up, doc?" I asked in my best Bugs Bunny voice.

"I'm going to knock you out," he said.

I thought Sue, Mary and Janice would kiss him.

After a brief discussion about allergies ("I'm only allergic to myself," I said), the doctor left and Brian, a nurse anesthetist, came in.

"Do you have any questions?" he asked.

"Yes," I responded. "Will you be giving me domestic beer or an import?" "You'll be getting craft beer," Brian said. "It's the best-quality brew." He should know because a friend of his owns a brewery. "By the way," Brian added reassuringly, "I won't be having any during the operation. I'll wait until tonight." "Cheers!" I said as Brian left. Then my urologist, Dr. Albert Kim, who would be performing the procedure, came in.

"Are you behaving?" he asked.

"Of course not," I replied.

"Good," he said with a smile. "See you in surgery." The operation was a success. I'm grateful to Kim and everyone at John T. Mather Memorial Hospital in Port Jefferson, N.Y., for taking such good care of me.

The next day, Louise called from the hospital to ask how I was feeling.

"Couldn't be better," I said. "It's been a rocky road, but the stone is gone." "Did she get the joke?" Sue asked after I hung up.

"I think so," I answered.

2011年3月22日星期二

Calcium: Myths and misconceptions

Calcium is no stranger to controversy, and its important role is often tarnished by unfounded contradiction. Its silent participation in troubled waters put its reputation in jeorpardy, wrongly accused of misdeeds it has not committed.

The guilty verdict dished out is often based on circumstantial evidence of its presence at the "crime scene". The most common type of kidney stone is composed of calcium oxalate. A senior citizen who has seen some miles often has opaque calcification of the artery leaving the heart (aorta) in a chest x-ray. In cardiovascular disease, the underlying fires of inflammation within the artery walls instigates deposition of calcium, making it an indirect predictor of the No.1 killer.

None of the above is the direct result of calcium causing mischief, but merely its response to disease and injury.

Calcium101

Calcium is the most abundant mineral in the body, and if it were possible to gather it all in a bag, it will weigh about a kilogram. About 99% is banked in the bones and teeth, and only 1% circulates freely in the blood, within cells, and the fluid between cells.

Calcium has an undeniable role in building up bone density, giving strength and integrity to our supporting framework. What many are unaware of is the myriad other cellular functions of calcium that keep us alive.

It plays a constant role in controlling traffic of incoming supplies of nutrients and the exit of biochemical wastes from the cells, the making of hormones, and the transmission of messages from one nerve cell (neurons) to another.

Last, but not least, is its involvement in muscle contractions, working in concert with another important player, magnesium, in the cellular "see-saw" where one comes in and the other goes out, alternating between muscle contractions and relaxation.

The daily movement of calcium commences with ingestion, where after dispersion and absorption in the gut, it meanders its way to the bones to build up "hardness", while a small portion is utilised for metabolic functions.

When demand exceeds supply, the mineral is withdrawn from the bone bank, the bones.

Installed within us is an automatic alarm system that keeps calcium levels within a physiologic range. Failure of this hardware will lead to disease if the calcium levels swing too high or drops too low.

Behind the thyroid in the neck is a gland (parathyroid) that secretes parathyroid hormones, which elevates blood calcium when its level drops, mobilising the shift from the bones into the circulation. Calcitonin is another regulatory hormone that moves calcium back into the bones.

Active vitamin D is the gatekeeper to the entrance of calcium, its presence being a prerequisite for effective absorption of the mineral. The dietary precursor of vitamin D is activated in a three-step process, with the initial ignition in the skin, aided by sun exposure, thus earning the label "sunshine vitamin".

A second process occurs in the liver, and the final step of activation is effected by the kidneys. Lack of sun exposure, liver or kidney disease will lead to poor calcium absorption, auguring the development of porous bones (osteoporosis).

Consumption matters

The average daily diet confers 350mg to 400mg of calcium. Gulping down a glass of milk adds another 250mg of calcium. However, absorption of dietary calcium is only about 40%. Infants to children aged five years require 300mg to 600mg calcium daily; those six to 10 years old require 800mg; those 11 to 18 years require 1,300mg; 19- to 50-year-olds require 1,000mg; those above 50 years/pregnant/lactating require 1,200mg; while perimenopausal women require 1,500mg. (The safe upper limit for children and adults is 2,500mg per day).

Calcium rich foods include dairy products (milk, cheese, yoghurt, eggs), tofu, sardines, and vegetables like cabbages, kale, and broccoli. One may also choose a "good" calcium supplement in the right dosage and right form to meet the dietary shortfall.

Calcium supplements are the most widely used and prescribed mineral supplement, and confusion abounds in choosing the right type, based on dose, form, and combination.

The capacity to absorb calcium from the gut is limited to 500mg at one pass. The most common and cheapest form is calcium carbonate (inorganic salt), and the absorption rate is about 30%, whereas calcium citrate is said to be better absorbed.

As the former enters the cavernous stomach, it drops into a pit of acid juices (hydrochloric acid), which react with the carbonate to form a "champagne-like" foam. Calcium carbonate has the notorious tendency to cause heartburn.

Subsequently, the partly dissolved tablet exits the stomach into the first part of the small intestines, where further down is a short segment that acts as the window of absorption. The activated form of vitamin D brokers the entry of calcium into the cells by a process called active transport, akin to an electrical pump.

Even as the remnants of calcium leave the site of active absorption, some still manage to gain entry by a different manner, called passive diffusion, and the rest makes its way to the rear exit.

If much of the calcium is poorly absorbed, the result is unpleasant constipation.

Other forms of calcium tablets include calcium gluconate and lactate.

There is such a complex interplay of factors that scientists are not in total agreement about calcium requirements. Even if adequate calcium is made available to the body, there is no guarantee that it will be incorporated into the scaffolding of the bone’s architecture.

The combination of activated vitamin D, magnesium, boron, silicon, copper, zinc and other trace minerals are required for calcium to be translated into improved bone density. Calcium is like the brick, but to cement them together, we need at least 20 other known nutrients to form the mortar to glue it together.

Unfortunately, how many of us are cellular scientists, and how many supplement makers understand the science?

Amidst all this scientific jargon brews confused hearsay, misconceptions and myths. Perhaps this is the forum to address some common issues.