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  Types of Ovarian Cancer

  There are four main types of ovarian cancer, each with its own natural history, treatment and outcome.

  Epithelian ovarian cancers make up 90% of all ovarian cancers. In turn, there are five different subtypes of epithelial ovarian cancer—serous, mucinous, endometrioid, clear cell and undifferentiated. They all come from the surface of the ovaries.

  Germ cell ovarian cancers are rare, tending to happen in women under 30 years of age. They arise from the eggs inside the ovary.

  Sex-cord stromal ovarian cancers are uncommon and can happen at any age. They arise from the tissues that secrete hormones.

  Borderline ovarian cancers are actually epithelial cancers, that are not as aggressive as the other ovarian cancers.

  There is currently no general population screening test available for ovarian cancer. (However, women who do have genetic family cancer genes should be reviewed annually, and have ultrasounds, blood tests and physical check-ups and examinations.) The lack of a reliable screening test for the general population is another reason why women tend to find out that they have ovarian cancer only when the disease is well advanced. A later diagnosis affects how well or how badly women fare with treatment. Studies done between 1992 and 1997 showed that only 42% of women diagnosed with ovarian cancer were still alive five years later. On the other hand, if the ovarian cancer is both diagnosed and treated early, over 80% of women will survive more than five years—the basic yardstick for cancer patients’ survival.

  Genetics of Ovarian Cancer

  First, 95% of all ovarian cancers happen in women without genetic risk factors. Second, many women with these risk factors never develop ovarian cancer.

  About 5% of ovarian cancers are related to inherited genetic factors. Most hereditary ovarian cancer is related to mutations in the BRCA1 gene. Fewer hereditary cancers are related to mutations in the BRCA2 gene.

  HNPCC (Hereditary NonPolyposis Colorectal Cancer) syndrome is related to an increased incidence of ovarian cancers and other cancers of the gut and the genitourinary system.

  Women who have a first degree relative (mother, sister or aunt) with ovarian cancer, and no other family history of this disease, have a risk of ovarian cancer only slightly above that for the general population. The vast majority (97%) of these women will never develop ovarian cancer.

  Women who have symptoms suggestive of ovarian cancer are usually investigated by a combination of a physical examination, a blood test for a tumour marker, and an ultrasound or CT scan of the pelvis. Surgery is necessary for a definite diagnosis and the treatment of the cancer. This is best done in a medical centre that specialises in treating ovarian cancer, as the disease is usually widespread. Chemotherapy is most often given to help destroy the cancer.

  One good side effect of the oral contraceptive pill is that it offers some protection from ovarian cancer, as does pregnancy and breast-feeding, which have the effect of ‘resting’ the ovaries.

  Ovarian Cancer Stats

  Ovarian cancer is the fifth most common cancer in women. It is less common than cervical cancer. About one in 70 women has a chance of developing ovarian cancer during her life—a lifetime risk of 1.4%. Most cases (90%) happen in women older than 40, the mean age at diagnosis being 63 years.

  During the reproductive years of her life, a woman will pop out some 400 eggs from her ovaries. We do not know exactly why, but it is protective with regard to ovarian cancer if the ovaries pop out fewer eggs. For example, during the nine months of a typical pregnancy, the ovaries will pop out no eggs at all. So risk factors include having few or no children, starting periods early and finishing them late in life and having the first child after the age of 30.

  Take Home Messages

  There are three Take Home Messages.

  First, new or persisting symptoms need to be checked, no matter how vague.

  Second, there is no screening test for ovarian cancer at the moment.

  Third, a pap smear, effective as it may be, looks only for early signs of cervical cancer, not ovarian cancer.

  References

  Neesham, Deborah, ‘Ovarian cancer screening’, Australian Family Physician, March 2007, pp 126–128.

  ‘Symptoms and ovarian cancer’, Editorial, The New York Times, 19 June 2007.

  It’s All a Bit of a Yawn

  During a meeting at the end of a long and hard day spent working on a totally new project (in the daring field of comedy-science TV), a bout of contagious yawning suddenly spread through the group. The person who started this mini yawning epidemic said, in her defence, that she must be low in oxygen. This was why she had yawned so widely—it was merely a silent, natural scream for more air (and oxygen). Like all good myths, it has a tiny whiff of truth.

  Yawning, O2 and CO2

  Certainly, after a few hours of constant breathing at rest the lungs become ‘stiffer’ and less compliant. And yes, one decent yawn will return the lungs to their usual flexibility. However, this does not affect blood oxygen levels—at least not in healthy people.

  One of the leading yawn experts on the planet is Robert R. Provine, Professor of Psychology at the University of Maryland, who has been studying yawning for decades. In 1987, his classic experiment found the link between yawning and the amount of oxygen that the volunteers breathed in. Although normal air is mostly nitrogen (about 80%) and only about 20% oxygen, for this experiment he ditched the wimpy 20% oxygen rubbish. He went all the way and gave his volunteers 100% oxygen to breathe, but they still yawned just as much. The five-times increase in oxygen had no effect.

  Professor Provine also found that most people never yawn when burning up lots of oxygen, e.g. when exercising hard.

  He also tested whether high levels of CO2 made you yawn. Carbon dioxide is manufactured in your body as a waste product. You breathe it out to get rid of it. The normal CO2 level in the atmosphere is about 0.03%. He gave his subjects levels 100 times greater—3–5%—and it didn’t make them yawn more often.

  So you can forget about low oxygen or high carbon dioxide being the causes of yawning.

  In the Beginning…

  The word ‘yawn’ comes from the Middle English word ‘yanen’, which in turn came from the Old English word ‘geonian’, which means ‘to gape’ or ‘to open wide’. So yes, chasms really do yawn beneath you. A yawn is a long, slow and deep inward breath, taken with a wide-open mouth, followed by a short outward breath lasting for an average of six seconds. The eyes sometimes close at the peak of the yawn, and water a bit.

  About half of all stretches will be accompanied by a yawn. However, it doesn’t really work the other way. Only about one in nine yawns are accompanied by a long, slow and luxurious stretch of the arms and legs. (The fancy word for a simultaneous ‘yawn and stretch’ is ‘pandiculation’).

  Practically all animals with backbones yawn. In most species, the males do most of the yawning, but in human beings, the balance is about 50:50 for men and women.

  We start yawning even before we are born, about 11 weeks after conception. It seems to help protect the baby’s developing lungs. The baby floats in amniotic fluid, a mixture of the baby’s urine and a liquid made in the lungs. The baby’s lungs do expand and contract but ‘breathe’ amniotic fluid, not air.

  We don’t know why unborn babies yawn. Perhaps yawning moves stagnant fluid out of the lungs or removes webs of tissue that might block the airways.

  Parents of young babies have told me that contagious yawning is a ‘one-way street’, the baby’s yawns will make the parents yawn but not the other way round. Parents have also informed me that they are able to ‘spread’ their yawn to the baby at around 8–36 months of age. I guess that the baby is Top Dog in the house, at least for a while.

  Of course, yawning is very important when you travel on aeroplanes. Yawning opens up the eustachian tubes, which run from the middle ear to the back of the throat. A few good yawns will relieve the pain of the air pressure, when the plane is taking off or landing.

  [Cut to man yawning]

  The word ‘yawn’ comes from the Middle English word ‘yanen’, which in turn came from the Old English word ‘geonian’, which means to ‘gape’ or ‘to open wide’.

  A yawn is a long and slow deep inward breath, taken with a wide-open mouth and followed by a short outward breath lasting for an average of 6 seconds.

  Weird Yawning Links

  Yawning has a number of strange links to different aspects of human experience.

  For example, the yawn has a strange link to sexuality. In male rats, medications that make them yawn and stretch will also give them an erection. In most human beings, antidepressant drugs such as clomipramine and fluoxetine can put a damper on sexual desire and performance. However, in a tiny minority of people these medications have a rather interesting side effect. Some of them have an orgasm whenever they yawn. I guess that this would be one group of people who would be happy to be cornered at a party by a really boring person…

  Here’s another weird link. Stretching of arms spontaneously when yawning can lead to a bizarre phenomenon in some stroke victims. A stroke occurs when part of the blood supply in the brain is blocked, causing localised damage to the brain and possible paralysis on one side of the body. Partially paralysed people cannot voluntarily move the arm on the affected side, no matter how hard they try. However, in 1923, the British neurologist Sir Francis Walshe noticed that when some stroke victims yawned, they could move their otherwise paralysed arm.

  And here’s another strange link. In heart attack victims and in people recovering in intensive care units, a spontaneous yawn is a sign that the person is hopefully on the way to recovery.

  A pilot of an RAAF search-and-rescue maritime patrol plane, a P3 Orion, told me of his
extensive experience over the Southern Ocean in severe and very turbulent weather, flying very low, looking for missing sailors. When he began to get a little airsick, he started yawning uncontrollably—very deeply, about once every minute. The yawns made it difficult to talk on the radio. If he had to fly in bad weather for a long time, he would get so tired that he would nod off and have a microsleep for five seconds at a time. This was not the best time to have a snooze—flying at 500 kph some 30 m over the ocean while doing hard turns and pulling lot of G-forces.

  It seems hard to believe that you could nod off in this kind of extreme flying. I wonder if these guys are so used to living on the edge, that they no longer get the adrenalin rush that would have terrified someone like me into being wide awake.

  Why Do We Yawn?

  People who suffer cerebral anaemia or particular problems with the medulla oblongata will yawn almost continuously. But, in general, we don’t really know why we yawn.

  People are most likely to yawn in the first hour after they have woken up or in the last hour before they go to sleep—or when they’re tired, bored, or doing long boring repetitive tasks.

  Yawn and Medical Emergency

  I was on a five-hour flight from Sydney to Perth when a call came over the plane’s public address system asking for a medical doctor. While I was trained as a medical doctor, my most recent clinical practice had been many years earlier when I was a doctor at the Kids’ Hospital (now known as the Children’s Hospital) in Sydney.

  My heart sank when I saw my patient—a stout, middle-aged man with all the signs and symptoms of a heart attack. There was a limited amount that I could do with the medical supplies on the plane. There was no defibrillator to kick-start his heart back to a regular rhythm if it became necessary. The aisle on the jam-packed plane was so narrow and he was so stout that it was next to impossible to perform CPR (Cardiopulmonary Resuscitation) if I had to. I sat with him and kept feeding him oxygen.

  And then he yawned. My heart leapt with joy. My medical teachers had told me that a yawn was often the sign that a patient was recovering from a medical crisis. As I sat beside him for the last hour of the flight, his hands became less clammy, his colour became more normal and his chest pain and tightness gradually decreased. I was so happy when I handed him over to the ambulance officers at Perth Airport. Later he phoned me to tell me that he was much better.

  Yes, yawning is correctly linked to tiredness and to boredom, although super-awake and super-interested people will sometimes yawn. Look carefully at athletes getting ready for a sports event. Having trained for ages for this one short event, they will be fully alert and well rested. And yet they will yawn before their race, boxing bout or parachute dive. Musicians about to perform will often yawn—perhaps because of nervousness. A Siamese Fighting Fish about to rumble with another Siamese Fighting Fish will yawn 300 times more often than usual and dogs preparing to attack will also yawn more frequently—perhaps in anticipation. Charles Darwin noted in 1873 that if a baboon is involved in a threat or a matter of passion it was more likely to yawn. These are all seemingly odd times for a yawn to erupt.

  One theory suggests that yawning is associated with a transition from awake to asleep (and vice versa), from alert to bored (and vice versa) and into sexual arousal (and vice versa). Yawning is linked to changing from any one activity to any other activity.

  Contagious Yawning

  However, we still don’t understand why yawning can be contagious.

  For a while, the yawn scientists thought that a circuit in the brain called the Mirror Neuron System might be involved. The brain cells in this circuit start firing when you do a particular activity and sense that somebody else is performing the same activity. However (and here’s the confusing part), they don’t fire when you see somebody else yawn and copy them.

  We do know that empathetic types (e.g. people who, say, express concern when you stub your toe) are more likely to ‘catch’ a yawn while ‘cold fish’ types are pretty much immune to yawning in synchrony. We also know that a yawn by a human being can be ‘caught’ by their pet dog or cat. Chimpanzees watching a video of other chimps yawning will also start to yawn.

  And finally, we know that thinking, hearing or reading about yawning has a 50% chance of setting off a bout of yawning. So, perhaps if this story made you yawn, you can identify yourself as a kind and caring soul, and there’s nothing boring about that.

  Other Theories of Yawning

  One theory of why we yawn relates to the veins that surround the muscles that open the jaws—the pterygoid venous plexus. Supposedly, blood low in oxygen accumulates there during boring activity (when you don’t use your jaw muscles much). Because the brain apparently doesn’t like having stagnant deoxygenated blood so close, it kicks a yawn into action. The yawn both moves the venous blood along toward the heart and brings a big lungful of new air on board.

  Another theory suggests that yawning helps regulate your body temperature. In one study volunteer yawners held temperature packs against their foreheads while watching others yawn. Warm (46°C) packs and room temperature packs had no change on the contagious yawning rate of the volunteers (about 41% of the time). However, cold packs on the forehead dropped this rate to just 9%.

  References

  Gallup, Andrew C. and Gallup, Gordon G. Jr., ‘Yawning as a brain cooling mechanism: nasal breathing and forehead cooling diminish the incidence of contagious yawning’, Evolutionary Psychology, 2007, Vol 5(1), pp 92–101.

  Hooper, Rowan, ‘You may want to yawn before reading this’, New Scientist, 30 June 2007, p 14.

  Platek, S.M., et al., ‘Contagious yawning: the role of self-awareness and mental state attribution’, Cognitive Brain Research, 2003, Vol 17, pp 223–227.

  Provine, R.R., et al., ‘Yawning: no effect of 3-5% CO2, 100% O2, and exercise’, Behavioural and Neurological Biology, November 1987, pp 362–393.

  Provine, Robert R., ‘Yawning: the yawn is primal, unstoppable and contagious, revealing the evolutionary and neural basis of empathy and unconscious behavior’, American Scientist, November 2005, pp 532–540.

  Schurmann, Martin, et al., ‘Yearning to yawn: the neural basis of contagious yawning’, NeuroImage, 15 February 2005, Vol 24, pp 1260–1264.

  Halley-less Comet

  Early in 2007, people in the Southern Hemisphere were lucky enough to get a visit from Comet McNaught, discovered in 2006 by the astronomer Robert McNaught. And following the rules, he was allowed to name it after himself—one of the advantages of being an astronomer.

  I was tremendously excited to see this comet with my own naked eyes. It was spectacular, multicoloured and huge, about five times the size of the Moon—if you were lucky enough to see it out of town, away from big city lights and pollution.

  And in 1994, I was also very excited to be on board a NASA jet carrying an infrared telescope down towards the Antarctic. Through the telescope I saw the huge holes punched into the face of the planet Jupiter by the fragments of Comet Shoemaker-Levy 9 discovered by Carolyn and Eugene Shoemaker and David Levy.

  On the other hand, Halley’s Comet which appeared in our skies in 1985–86 was different. First, it was not so impressive and second, it was not named after the person who discovered it.

  History of Comets

  Comets, which have been observed for thousands of years, appear briefly in the sky, often with a long luminous tail. Indeed, the word ‘comet’ comes from the Greek word kometes, which means ‘hairy one’, referring to the long tail. In ancient times, their sudden appearance was thought to indicate the arrival of calamitous events, such as plague, flood or the death of some big wig.