Sex-Gender Differences in Medical Research

We are only very slowly recognizing the many biological and medical differences between males and females (and masculine/feminine)—besides the obvious ones related to reproduction. There are divergent patterns in the anatomy and physiology of perhaps every body system. However, in medical research male and female subjects are often grouped together in a way that obscures those divergent patterns.

Two "viewpoint" articles in the Journal of the American Medical Association (JAMA) today focus a light on this issue and point the way to improved—more clinically useful—medical research. Links to both articles are listed below.

As one of the articles points out, women have been included in medical trials for only the past few decades. So there is still a lot of work to be done to shore up the database of male-female differences. But also a lot of work to be done in sorting out male-female patterns of health and disease. Then even more work in making this new knowledge part of the everyday practice medicine.

Both articles are brief and relatively nontechnical, but when read together, they provide an important message for those of us teaching pre-clinical health professionals in A&P. That message is that we should consider introducing—then reinforcing—the notion of body-wide sex and gender differences.

Both articles give examples of such differences, but many more are to be found elsewhere, as well. Not that we should teach every possible example in the undergraduate A&P course. However, the general concept of functional variation between males and females may be an important one to emphasize as a sub-theme in our story of the human body.

What can we use from this in teaching undergraduate A&P? 

• Consider making sex differences a sub-theme in your A&P course.
• Occasionally point out examples of structural, functional, and clinical patterns of variation that differ between males and females.
• Compare and contrast sex differences with other types of pattern variations.
• Discuss "patterns of variability" in contrast to a strictly "binary" view.
• Consider bringing up sex-difference research that is not yet fully supported.
• Discuss whether more attention to sex differences across topics in scientific research might help advance this area of knowledge.
• Discuss the opposing view that there are no clinically significant biological differences between males and females other than those related to reproduction.
• Look for such examples in your textbook and other teaching/learning resources and point them out to your students.
• Consider having a classroom or online discussion of this topic. 
• Ask students to post links to articles that discuss male-female patterns of variation
• Post to course discussion or course social media channel
• Bring to class or email to instructor to share with class
• Post on bulletin board


• Bring up this issue when discussing how science is done.
• Consider asking students what effects on public health a more thorough consideration of sex differences may produce.
• Ask students to look at a study and ask whether sex differences were thoroughly accounted for in the methodology. Could this affect how the study is interpreted and applied in the clinic?

Want to know more? 

Consideration of Sex Differences in Medicine to Improve Health Care and Patient Outcomes

• Marianne J. Legato, MD; Paula A. Johnson, MD, MPH; JoAnn E. Manson, MD, DrPH.
• JAMA. Published online October 31, 2016. doi:10.1001/jama.2016.13995
• One of the two articles cited in the post above.
• my-ap.us/2f1pwEv

Reporting Sex, Gender, or Both in Clinical Research? 

• Janine Austin Clayton, MD; Cara Tannenbaum, MD, MS
• JAMA. Published online October 31, 2016. doi:10.1001/jama.2016.16405
• One of the two articles cited in the post above.
• my-ap.us/2f1jcwM

Let’s Talk About Sex…and Gender!

• Amanda M. Rossi, PhD; Louise Pilote, MD, MPH, PhD
• Circulation: Cardiovascular Quality and Outcomes. 2016; 9: S100-S101 doi: 10.1161/CIRCOUTCOMES.116.002660
• Brief article that addresses the issue of terminology, specifically distinguishing between terms that address sex (male, female) and gender (masculine, feminine). Includes a solid list of references.
• my-ap.us/2f1Y3Tr

Q-angle image: OpenStax College

Mutations in Mitochondrial DNA

A new study suggests that DNA mutations in some of the mitochondria of healthy people may be a lot more common than scientists thought.

The term heteroplasmy describes a situation in which some mitochondria of a cell have mutant mitochondrial DNA (mtDNA) and other mitochondria have normal mtDNA.  Cell function can become disordered, perhaps producing disease, when the balance of mutant vs. normal mtDNA crosses a certain threshold.

The recent study shows that about 90% of healthy people studied in the 1000 Genomes Project had at least one heteroplasmy.  Some of these (about 20%) have been shown to correlate to disease.  That's a lot more than we were thinking prior to the study (25%-65% heteroplasmy rate).

We don't  know the significance of this finding yet, but it could influence how likely it is for mitochondrial diseases to develop over time—or to be inherited.  Could the mutant/normal mtDNA balance get skewed as oocytes form, thus giving different offspring different probabilities of inheriting mitochondrial disorders?  Or change the probabilities from one generation to the next?  Mitochondrial dysfunction is thought to be a mechanism of aging—could the rate of heteroplasmy be part of the aging mechanism?

What can we use from this in teaching undergraduate A&P?  The fact that we now know that mtDNA mutations are common in healthy people will be interesting and useful to students.


Want to know more?

Mutations Pervade Mitochondrial DNA

• Jyoti Madhusoodanan. The Scientist (the-scientist.com) July 7, 2014
• This is a plain-English article summarizing the new findings; includes quotes from the researchers.
• my-ap.us/1oo18X8 

Extensive pathogenicity of mitochondrial heteroplasmy in healthy human individuals

• K. Ye et al., Proceedings of the National Academy of Science (PNAS), doi:10.1073/pnas.1403521111, 2014. 
• This is the original research report.
• my-ap.us/1sDPV8S

Want a FREE labeled image of mtDNA that you can use in your presentation, handout, or other course material?
my-ap.us/1ncmAxl

Virginia Johnson Masters, sex research pioneer, dead at 88

On Wednesday of this week, just a few miles from my home in Missouri, Virginia Johnson Masters passed away at age 88.

Most of you are aware of the pioneering work in human sexual physiology she and her late ex-husband, William Masters, undertook at Washington University in St. Louis during the mid-20th century.  I briefly underscored that work in several of my textbooks:

"The study of human reproduction, and especially sexual function, has many cultural implications. So it is no wonder that American researchers William Masters and Virginia Johnson encountered a great deal of controversy during their decades of pioneering work in the field of human sex and reproduction. They were the first to study human sexual physiology in the laboratory. William Masters was a gynecologist (physician specializing in women's health) and Virginia Johnson was a psychologist. In 1966, their book Human Sexual Response clearly explained the physiology of sex for the first time. Besides making discoveries in the physiology of human sex and reproduction, they also developed therapies for treating sex-related conditions, and they trained therapists from around the world. In addition to the broad fields of biology, medicine, psychology, and the behavioral sciences, the pioneering work of Masters and Johnson paved the way for advances in such diverse and specialized areas of knowledge as comparative neuroscience and social dynamics. Today, there are many opportunities to apply knowledge of reproductive science in a variety of professions."

You may also recall my previous article Masters of Sex, in which I related some of my experiences with Johnson's late ex-husband and collaborator, Bill Masters.

With the Showtime network about to debut their new miniseries Masters of Sex, in which the character of Virginia Johnson plays a pivotal role, students will likely be bringing their curiosity about Masters and Johnson's work to their A&P courses.

Want to know more?

Virginia Johnson, Widely Published Collaborator in Sex Research, Dies at 88

• By MARGALIT FOX
• The New York Times Published: July 25, 2013
• Detailed obituary
• my-ap.us/13jaA4r

Masters of Sex

• by Kevin Patton
• The A&P Professor May 12, 2009
• Brief article about Masters, Johnson, the recent book about them (on which the Showtime series is based), and Masters's unforgettable presentation at the HAPS Conference in 1995
• my-ap.us/18HBhYx

Masters of Sex

• by Thomas Maier
• Basic Books April 13, 2009 432 p.
• An amazing book about Masters and Johnson's story.  HIGHLY recommended reading for all A&P teachers!
• amzn.to/12sLRQb

Related textbook content

• Anatomy & Physiology 8th ed.  Chapters 34 and 35 my-ap.us/QZTbK1
• Essentials of Anatomy & Physiology Chapters 24 and 25 my-ap.us/SCfNlj  
• The Human Body in Health and Disease 6th ed. Chapter 23 (see bio on p. 610-611) my-ap.us/X71LJO 
• Structure & Function of the Body 14th ed. Chapter 23 (see bio on p. 459) http://my-ap.us/10s50MH

Stem cells in the ovary

Beginning about 8 years ago, scientists began providing evidence that apparently overturns the dogma that adult ovaries do not contain stem cells capable of producing oocytes.  Jonathon Tilly found such cells first in mice, then later in middle-aged women. Other labs have replicated such findings.

However, a study by members of Kui Liu's lab published today disputes that the stem cells actually produce oocytes.  Needless to say, this is stirring up quite a bit of controversy.  Tilly believes Liu was looking at oocytes, not stem cells.  Liu doesn't agree.

What does this mean for the undergraduate A&P class?  I discuss the recent discoveries of stem cells in adult ovaries in my course.  I use it as an opportunity to point out that there is still much to learn about how the human body works . . . that we are continually surprised by new research findings.  This is part of a year-long subtext of "how science works."  I tell my A&P students that I'm telling them "the last, best story" about the human body.  But that my story changes from year to year as scientists tease out more information . . . and thus revise "the story."

How does this fit in?  Well, isn't this how science is supposed to work?  Wouldn't it seem logical that it is in the best interest of everyone to have vigorous debate and extensive re-examination before we throw out the last, best story in favor of a new version?

The first article below briefly summarizes the issues involved in today's publication.


Want to know more?

Ovarian Stem Cell Debate
Ed Yong
The Scientist (online) July 9, 2012
[Brief article discusses  that opinion is divided on a new paper showing that adult ovaries do not contain egg-making stem cells, contrary to two recent studies that appeared to overturn longstanding dogma.]
my-ap.us/Mf1Y5w

Experimental evidence showing that no mitotically active female germline progenitors exist in postnatal mouse ovaries
H. Zhang et al.
Proceedings of the National Academy of Sciences doi:10.1073/pnas.1206600109
[Recent paper disputing presence of stem cells in adult ovaries]
my-ap.us/RX4McG

Ovarian Stem Cells in Humans?
Sabrina Richards
The Scientist (online) February 27, 2012
[Brief summary of recent paper by Tilly's lab stating that adult human ovaries contain a population of stem cells capable of generating immature egg cells.]
my-ap.us/OWGY8G

Oocyte formation by mitotically active germ cells purified from ovaries of reproductive-age women
Y.A.R. White et al.
Nature Medicine 18:413–21, 2012.
[Original research paper by Tilly's lab showing presence of stem cells in human ovaries.]
my-ap.us/LFaYqX

The image above is copyright free and can be used in your course!

Progesterone's action on sperm finally solved

Two recent articles in Nature reveal a mystery that's been puzzling physiologists for a couple of decades . . . how does progesterone signal sperm cells?

The short version of the story is this . . .

Progesterone is released from the cumulus cells that cling to the outside of the zona pellucida surrounding the ovum. This progesterone binds directly to calcium channels in the sperm's plasma membrane to open.  Influx of calcium ions triggers an increase in flagellum activity.  This increased work is needed for the sperm to get through the zona to the ovum.

Progesterone is a steroid hormone and thus usually enters its target cell and activates transcription of a gene.  In this case, however, progesterone instead directly triggers a calcium channel.  It's not even a second-messenger system, but a direct binding to the channel.

Secretion of progesterone by cumulus cells apparently also provides a chemical gradient that helps sperm navigate toward the ovum.

Recall also that calcium influx into the ovum triggered by contact with a sperm cell plays a role in producing changes within the ovum that result in successful fertilization.

I recommend that my students keep running concept lists on recurring themes or actors in story of human biology.  Here's something they can now add to their calcium list.  Now they can see that a calcium gradient is a truly multipurpose tool in the body.  (For more about running concept lists see my-ap.us/hCIA9X)

Want to know more?

Sperm mystery solved: Scientists identify the channel by which progesterone activates sperm to swim toward an egg
M. Scudellari
The Scientist Published online 16th March 2011
[Nice summary of the significance of the discovery]
my-ap.us/grpcTp

Female hormone could be key to male contraceptive: Progesterone-sensing molecule that guides sperm to egg offers fertility solution.
E. Callaway
NatureNews Published online 16 March 2011 | Nature | doi:10.1038/news.2011.163
[Summary article outlining the papers published in Nature]
my-ap.us/fJNaYk

Progesterone activates the principal Ca2+ channel of human sperm
Lishko et al.
Nature  471:387–391 17 March 2011 doi:10.1038/nature09767
[Original research findings]
my-ap.us/gxcomX

The CatSper channel mediates progesterone-induced Ca2+ influx in human sperm
Strunker et al.
Nature 471:382–386 17 March 2011 doi:10.1038/nature09769
[Original research findings] my-ap.us/g14eTK

From The A&P Professor archive

New discovery about sperm's ability to swim
K. Patton
The A&P Professor published online Feb 18, 2010
[Summary of new discovery that when sperm enter female tract, proton channels in the sperm head open and the resulting pH drop triggers influx of calcium, which gets the flagella started in the first place.  That darn calcium shows up in every part of this story, eh?]
my-ap.us/dExdEK

Nobel Prize: Test Tube Babies

This morning, we heard the news . . . the 2010 Nobel Prize in Medicine or Physiology is awarded to Robert G. Edwards "for the development of in vitro fertilization."


Professors and students using my Anatomy & Physiology (7th ed.) textbook can access an article on in vitro fertilization (IVF) at A&P Connect online at evolve.elsevier.com

If you are thinking of mentioning this award in your classes this week, which I am planning to do myself, you are welcome to use the following information from the Nobel Committee, as well as the images linked to the thumbnails presented here (scroll down to the bottom for more).

Of course, be aware that the use of IVF is condemned by some religious groups (for example, see Dignitas Personae) and thus classroom discussions may become heated.

There is also advanced information available at the Nobel website.  This is a nice publication that summarizes the science.

If you want a short set of slides that you can use today in your class, then use this link:

theAPprofessor.org/slides/2010-Nobel-IVF.pptx

 

Summary

Robert Edwards is awarded the 2010 Nobel Prize for the development of human in vitro fertilization (IVF) therapy. His achievements have made it possible to treat infertility, a medical condition afflicting a large proportion of humanity including more than 10% of all couples worldwide.

As early as the 1950s, Edwards had the vision that IVF could be useful as a treatment for infertility. He worked systematically to realize his goal, discovered important principles for human fertilization, and succeeded in accomplishing fertilization of human egg cells in test tubes (or more precisely, cell culture dishes). His efforts were finally crowned by success on 25 July, 1978, when the world's first "test tube baby" was born. During the following years, Edwards and his co-workers refined IVF technology and shared it with colleagues around the world.

Approximately four million individuals have so far been born following IVF. Many of them are now adult and some have already become parents. A new field of medicine has emerged, with Robert Edwards leading the process all the way from the fundamental discoveries to the current, successful IVF therapy. His contributions represent a milestone in the development of modern medicine.

Infertility – a medical and psychological problem

More than 10% of all couples worldwide are infertile. For many of them, this is a great disappointment and for some causes lifelong psychological trauma. Medicine has had limited opportunities to help these individuals in the past. Today, the situation is entirely different. In vitro fertilization (IVF) is an established therapy when sperm and egg cannot meet inside the body.

Basic research bears fruit

The British scientist Robert Edwards began his fundamental research on the biology of fertilization in the 1950s. He soon realized that fertilization outside the body could represent a possible treatment of infertility. Other scientists had shown that egg cells from rabbits could be fertilized in test tubes when sperm was added, giving rise to offspring. Edwards decided to investigate if similar methods could be used to fertilize human egg cells.
It turned out that human eggs have an entirely different life cycle than those of rabbits.  In a series of experimental studies conducted together with several different co-workers, Edwards made a number of fundamental discoveries. He clarified how human eggs mature, how different hormones regulate their maturation, and at which time point the eggs are susceptible to the fertilizing sperm. He also determined the conditions under which sperm is activated and has the capacity to fertilize the egg. In 1969, his efforts met with success when, for the first time, a human egg was fertilized in a test tube.
In spite of this success, a major problem remained. The fertilized egg did not develop beyond a single cell division. Edwards suspected that eggs that had matured in the ovaries before they were removed for IVF would function better, and looked for possible ways to obtain such eggs in a safe way.

From experiment to clinical medicine

Edwards contacted the gynecologist Patrick Steptoe. He became the clinician who, together with Edwards, developed IVF from experiment to practical medicine. Steptoe was one of the pioneers in laparoscopy, a technique that was new and controversial at the time. It allows inspection of the ovaries through an optical instrument. Steptoe used the laparoscope to remove eggs from the ovaries and Edwards put the eggs in cell culture and added sperm. The fertilized egg cells now divided several times and formed early embryos, 8 cells in size (see figure).
These early studies were promising but the Medical Research Council decided not to fund a continuation of the project. However, a private donation allowed the work to continue. The research also became the topic of a lively ethical debate that was initiated by Edwards himself. Several religious leaders, ethicists, and scientists demanded that the project be stopped, while others gave it their support.

The birth of Louise Brown - an historic event

Edwards and Steptoe could continue their research thanks to the new donation. By analyzing the patients' hormone levels, they could determine the best time point for fertilization and maximize the chances for success. In 1978, Lesley and John Brown came to the clinic after nine years of failed attempts to have a child. IVF treatment was carried out, and when the fertilized egg had developed into an embryo with 8 cells, it was returned to Mrs. Brown. A healthy baby, Louise Brown, was born through Caesarian section after a full-term pregnancy, on 25 July, 1978. IVF had moved from vision to reality and a new era in medicine had begun.

IVF is refined and spreads around the world

Edwards and Steptoe established the Bourn Hall Clinic in Cambridge, the world's first centre for IVF therapy. Steptoe was its medical director until his death in 1988, and Edwards was its head of research until his retirement. Gynecologists and cell biologists from all around the world trained at Bourn Hall, where the methods of IVF were continuously refined. By 1986, 1,000 children had already been born following IVF at Bourn Hall, representing approximately half of all children born after IVF in the world at that time.

Today, IVF is an established therapy throughout the world. It has undergone several important improvements. For example, single sperm can be microinjected directly into the egg cell in the culture dish. This method has improved the treatment of male infertility by IVF. Furthermore, mature eggs suitable for IVF can be identified by ultrasound and removed with a fine syringe rather than through the laparoscope.
IVF is a safe and effective therapy. 20-30% of fertilized eggs lead to the birth of a child. Complications include premature births but are very rare, particularly when one egg only is inserted into the mother. Long-term follow-up studies have shown that IVF children are as healthy as other children.
Approximately four million individuals have been born thanks to IVF. Louise Brown and several other IVF children have given birth to children themselves; this is probably the best evidence for the safety and success of IVF therapy. Today, Robert Edwards' vision is a reality and brings joy to infertile people all over the world.

Robert G. Edwards was born in 1925 in Manchester, England. After military service in the Second World War, he studied biology at the University of Wales in Bangor and at Edinburgh University in Scotland, where he received his PhD in 1955 with a Thesis on embryonal development in mice. He became a staff scientist at the National Institute for Medical Research in London in 1958 and initiated his research on the human fertilization process. From 1963, Edwards worked in Cambridge, first at its university and later at Bourn Hall Clinic, the world's first IVF centre, which he founded together with Patrick Steptoe. Edwards was its research director for many years and he was also the editor of several leading scientific journals in the area of fertilization. Robert Edwards is currently professor emeritus at the University of Cambridge.

References:

Edwards RG. Maturation in vitro of human ovarian oocytes. Lancet 1965; 2:926-929.

Edwards RG, Bavister BD, Steptoe PC. Early stages of fertilization in vitro of human oocytes matured in vitro. Nature 1969; 221:632-635.

Edwards RG, Steptoe PC, Purdy JM. Fertilization and cleavage in vitro of human oocytes matured in vivo. Nature 1970; 227:1307-1309.

Steptoe PC, Edwards RG. Birth after the reimplantation of a human embryo. Lancet 1978; 2:366.

Edwards RG. The bumpy road to human in vitro fertilization. Nature Med 2001; 7:1091-4.

The preceding information is from "The 2010 Nobel Prize in Physiology or Medicine - Press Release". Nobelprize.org. 4 Oct 2010 http://nobelprize.org/nobel_prizes/medicine/laureates/2010/press.html


Some images you may find useful (click each thumbnail)

Sperm injection into oocyte

Human embryos developing in vitro

Robert G. Edwards

PDF from the Nobel website

Nobel medal

Sex differences in body fat distribution

When discussing sex differences in body fat distribution in my A&P course, I off-handedly refer to the roles of sex hormones in regulating the development that leads to these differences.  But how much do we really know about how that works?  Some recent work sheds a bit of light on that.

For example, a research review recently appearing in Obesity Reviews shows that indeed estrogen is responsible for promoting fat deposition in adult women.

Another recent article, this one in The International Journal of Obesity, suggests that there is a huge difference between the gene activity in male fat vs. female fat.  That is, the anatomy and physiology of male fat and female fat differs far more than anyone has yet realized.

Why Do Women Store Fat Differently From Men?.
University of New South Wales.
ScienceDaily 4 March 2009. 17 May 2010
[Brief synopsis of a research review from Obesity Reviews]

Does oestrogen allow women to store fat more efficiently? A biological advantage for fertility and gestation
A. J. O'Sullivan
Obesity Reviews Volume 10, Issue 2, Date: March 2009, Pages: 168-177
[Research review]

Belly Fat or Hip Fat: It Really Is All in Your Genes, Says Researcher.
UT Southwestern Medical Center.
ScienceDaily 16 May 2010. 17 May 2010

A microarray analysis of sexual dimorphism of adipose tissues in high-fat-diet-induced obese mice. 
K L Grove, et al.
International Journal of Obesity, 2010; DOI: 10.1038/ijo.2010.12
[Research article]

Artificial life?

Once they "get" the basic idea of molecular genetics, my A&P students become fascinated with those teeny-weeny molecules can have such huge impacts on the structure and function of the body.  On the drive home from campus today, I heard a great story on NPR about the announcement by Craig Venter that his team has successfully created a living, reproducing cell using completely synthetic DNA.  

They did this by using yeast cells to assemble smaller, synthesized bits of DNA and transferring it to living cells, which then reproduced the genome in offspring cells. 

While this is a long way from the claims (and concerns) of "creating artificial life," it is a huge discovery.

If you want to hear more about this, listen to the story yourself at Scientists Reach Milestone On Way to Artificial Life.

.

New discovery about sperm's ability to swim

Scientists have found the trigger that gets sperm swimming in the female reproductive tract.

Sperm cells in the testis are pretty quiet . . . they don't seem very interested in swimming.  However, after they are ejaculated into the female reproductive tract they become activated and get with the program. We already knew that the sperm cells need to raise their pH in order to kick into their swimming mode . . . but we didn't know how that is actually done.

In an article in the journal Cell, researchers report that they have the answer . . . one-way proton (H+) channels called Hv1 that open when sperm enter the female reproductive tract.  Increasing the intracellular pH triggers the influx of calcium ions, which in turn activate the sperm flagellum.  And they're off!

The increase in intracellular sperm pH also enables the sperm's acrosome to become activated and get ready to do its job, too.

Hv1 may be a key to triggering the hyperactivation and capacitation of sperm necessary for male fertility.

The researchers also found that a chemical similar to the active ingredient in marijuana inhibits the Hv1 channels and thus reduced fertility.  Perhaps this explains low fertility among males who are chronic users of marijuana.  And perhaps this opens the door to discovering chemicals that can be used to regulate the sperm fertility.

Want to know more?

Sperm's pore propulsion

Laura Sanders

Science News web edition : Thursday, February 4th, 2010

[Summary article includes a cool fluorescent micrograph.]

Acid extrusion from human spermatozoa is mediated by flagellar voltage-gated proton channel. 
Lishko, P.V. et al.
Cell Volume 140, Issue 3, 327-337, 5 February 2010
[Original research article with some fabulous images in the graphical abstract and an excellent movie that features the scientists explaining their discovery. ]

Why cells cooperate

Here's a nice little "animated clay" video that zeroes in on the "society of cells" concept that lies at the heart of homeostasis.   Because it goes on to emphasize the role of reproductive cells in a multicellular organism, it may be useful to help our A&P students connect reproduction to the concept of overall body homeostasis.

I saw this video on public radio's Science Friday website, where they have a weekly video recommendation.

The video comes from a collection of videos at creaturecast.org that are truly amazing.  Not very many directly relate to human anatomy and physiology . . . but, wow, they are fascinating.  For example, a recent posting discusses how mitochondria and other erstwhile endosymbionts can play a variety of roles such as acting as lenses for simple animals. I teach the serial endosymbiosis theory (SET)  in my A&P course . . . so this little factoid may help spice up that discussion.

So watch the FREE video about cell cooperation in a multicellular organism and let me know what you think!

CreatureCast Episode 2 from Casey Dunn on Vimeo.

Placenta, anyone?

OK, if you have a weak stomach DO NOT READ THE REST OF THIS MESSAGE.

Or better, I just won't even comment on this one . . . just read it for yourself:

Cooking with Joel Stein: How to Eat a Placenta
Joel Stein
Discover Discoblog accessed online 9 July 2009
[no comment!]

Want a FREE slide with a photo of a placenta? Click here for a slide from the Lion Den Slide Collection. FYI this is a "family photo" . . . the placenta seen in the image was photographed shortly after the birth of my youngest son, Luke. The maternal side of the placenta is clearly visible.

FYI, we ate SALAD and BURGERS for dinner that evening!

For more FREE slides, see FREE SLIDES at The A&P Professor website.

To access FREE editable slides from the Lion Den Slide Collection, including "bonus slides" not seen on the website, then go here.

{Click here to access the FREE image seen in this blog post . . . although I think a sprig of cilantro and contrasting cloth placemat would have made for a better presentation.}

New NIH policy on human stem cell research

For those who want to be "up to speed" on official policy when the inevitable discussion of human embryonic stem cell research pops up in class, this is just in from the National Institutes of Health (NIH) . . . revised guidelines that permit research on embryonic cell lines go in to effect TODAY.

From the official notice:

"On March 9, 2009, President Barack H. Obama issued Executive Order (EO)13505 Removing Barriers to Responsible Scientific Research Involving Human Stem Cells. The EO states that the Secretary of Health and Human Services, through the Director of NIH, may support and conduct responsible, scientifically worthy human stem cell research, including human embryonic stem cell (hESC) research, to the extent permitted by law. NIH published draft Guidelines for research involving hESCs in the Federal Register for public comment, 74 Fed. Reg. 18578 on April 23, 2009. The comment period ended on May 26, 2009. Approximately 49,000 comments on the draft Guidelines were submitted to NIH by patient advocacy groups, scientists and scientific societies, academic institutions, medical organizations, religious organizations, private citizens, and members of Congress.

The final NIH Guidelines for Human Stem Cell Research implementing the EO and establishing policy and procedures under which the NIH will fund such research, were released today and are available at http://stemcells.nih.gov/index.asp. They will be effective on July 7, 2009. Public comments on the draft Guidelines were also released today and are available at http://stemcells.nih.gov/index.asp.

The Guidelines will ensure that NIH-funded research in this area is ethically responsible, scientifically worthy, and conducted in accordance with applicable law. Internal NIH policies and procedures, consistent with the EO and these Guidelines, will govern the conduct of intramural NIH stem cell research.

The Guidelines prescribe the assurances and supporting documentation that must accompany requests for NIH funding for research using hESCs, and describe research that is not eligible for NIH funding. NIH will provide additional guidance concerning the implementation of the Guidelines and the status of pending applications in future Guide Notices.
Ongoing NIH-supported research involving previously approved hESC lines may continue. No new uses of hESC may be initiated in ongoing funded studies unless reviewed and approved by the NIH."

Read the new NIH Guidelines at http://stemcells.nih.gov/policy/2009guidelines.htm

Check out this article about the new guidelines, including the context and background:

NIH loosens stem cell consent rules
Elie Dolgin
The Scientist (online) posted 6th July 2009 07:58 PM GMT

Read my recent blog article Science controversies in the news

Masters of Sex

I just downloaded the new book Masters of Sex to my Kindle.

Before I had a chance to get very far with it, I happened to tune into an interview with author Thomas Maier on our local public radio station. Now I'm even more anxious to explore this book further.

Maier does a great job of explaining and underscoring the pivotal role of William Masters and Virginia Johnson in discovering some of the basic principles of sexual anatomy and physiology.

Known to most as Masters and Johnson, in the book we come to know them as Bill and Ginny.

Most importantly, however, we more greatly appreciate their roles in pioneering the scientific study of sexual biology and developing therapies that (still) really help people. As we learn in the book, their accomplishments really were remarkable . . . and, alas, really are underappreciated.

I had the good fortune of knowing Bill Masters near the end of his life. He had just retired from the Masters and Johnson Institute when I asked him to be the keynote speaker at the 1995 Human Anatomy and Physiology Society (HAPS) Conference in St. Louis. He graciously agreed to something he had not done for years . . . and (as it turns out) never would again: speak at a scientific conference.

Wouldn't you think someone of his stature would have been a frequent speaker at such conferences? I asked him about that. It turns out that he was so vigorously harassed at scientific meetings (both by scientists in the meetings and protesters outside the meetings) that he adopted the strategy of avoiding such venues. But our meeting was different . . . we wanted to sit at the feet of the "Master" and learn about his adventures. He knew we were teachers wanting to learn and not suspicious investigators wanting to debunk.

And he did not disappoint! After showing us a film from his research program . . . a film of the "vaginal sweat" lubrication forming on the vaginal wall during the female sexual response (oh my gosh) . . . he regaled us with fascinating stories and anecdotes from a lifetime of pioneering research in the most fascinating area of human biology.

Bill and I spent many hours on the phone before and after that conference . . . he loved telling stories. His soft-spoken, self-effacing style of telling the stories seemed at odds with the honestly ground-breaking work he was describing.

All of my textbooks feature boxed essays that underscore the pioneering roles of Masters and Johnson. If you want to see why they deserve this place of honor, you'll want to read Masters of Sex.

Masters of Sex
Thomas Maier
Basic Books April 13, 2009 432 p.

Thomas Maier interview
St. Louis on the Air
KWMU/St. Louis 7 May 2009

Read about another great sex book at The A&P Professor website.

Implantation of an embryo

I recently ran across a cool FREE video showing the implantation of an embryo into the wall of the uterus. The source is not clear on which placental mammal is shown--but really, at this stage it's probably pretty much the same for all of us, eh?

This would be a good video to embed in a PowerPoint slide (or link to it from a slide or lecture outline) when discussing reproduction/development. Click a button at the bottom of the viewer to expand the player, or get the code to link or embed the video into your material.

Here's the video:

[The video player embedded here may not appear in your news feed or emailed newsletter. Go to The A&P Professor blog to access the video viewer. Go to The A&P Professor website to learn how to embed the video in your PowerPoint or webpage . . . or simply link to it from your own email or webpage.]

Human fertility gene found

Here's another little nugget to throw into your lecture on reproduction . . . researchers recently identified a gene that improves fertility in humans.

The CFTR (cystic fibrosis transmembrane conductance regulator) gene in chromosome 7 (q31.2) may have a single amino acid substitution (valine instead of methionine in exon 10) that is correlated with improved fertility among male parents.

You may recall that different mutations of the CFTR gene may instead cause cystic fibrosis (CF) [see Anatomy & Physiology 7ed. p. 119-120, 1118-1119].

This nugget can be used in your A&P class to emphasize the concept that the amino acids assembled during translation from the genetic code have to be in the specific and exact order in order to function properly. Mutations to this gene, for example, can reduce normal function (as in a CF mutation) . . . or they can improve function (as in the fertility-enhancing mutation described here).

This nugget can also be used to explain why it's important to know about amino acids and protein structure . . . and the relationship of the genetic code to this structure. Perhaps it's a good idea to even be able to recognize the names of amino acids like valine and methionine--news such as this will become more and more commonplace as the years go by and this will become common and expected knowledge among health professionals.

Obviously, this new information can color any discussions you have in your course regarding genetic mechanisms in general and genetic mechanisms of disease in particular.

Want to know more? Check this out:

Human Fertility Gene Found
Elie Dolgin
The Scientist 3 April 2009
[Good summary article about the discovery, which was presented on April 2, 2009, and will be published in the Proceedings of the National Academy of Sciences.]

[Click the image above for a FREE illustration that you can use in your class.]

Penile fractures, pop culture, and job security

In my blog for students The A&P Student, I recently pointed out that they of course want to apply their increasing expertise in human anatomy and physiology to their experience of popular culture.

They've already probably caught themselves second-guessing some of the diagnoses of Dr. House's team . . . at least those lame ones offered during the first fifteen minutes of an episode. Or the really off-the-mark versions of human structure and function woven into episodes of Fringe.

I told them to get used to it. Apparently, the big money that goes into TV and movie productions does NOT go to anyone who passed a basic A&P course!

Dr. Patton's Theory of Media Science (Dr. P's TMS) . . .which I just made up after years of mulling it over . . . and shouting it to my television screen . . . states that

"biological accuracy of a science-based fictional media production is inverse to the total budget for special effects in the production."

My hope is that producers will eventually recognize the validity of my theory, and the growing population of A&P-educated viewers who can spot a stupid science "fact" that really doesn't have to be there to make the story flow or to keep the special effects within budget or allow for a snappy movie or episode title.

Then these cutting-edge producers will spring for a modest fee for an A&P consultant in each production. Which will spur an increasing demand for graduates of my A&P courses. Which will increase my job security. And then perhaps one day this trend will help me find a part-time job when I retire . . . perhaps an A&P consulting job that also involves brief, well-paid, guest-starring roles and sharing beers and pizza with my favorite TV and movie stars.

However, a recent episode of Grey's Anatomy (season 5, episode 513) brought up an anatomical issue that is rarely discussed in A&P courses . . . and so A&P students might wonder "can this be true?!" Or even, "PLEASE tell me this cannot be true!"

Yes, as I'm sure you already know, one CAN break a penis. In fact, it's a more common injury than most people suspect.

Why don't we hear about it more often?

First, if you or your partner has broken a penis, would you be talking it up everywhere you go . . . as one might with a broken leg? Second, let's face it . . . one would have a cast that's out there asking to be asked about, right? Third, at least in my part of the world . . . we simply don't talk much (out loud, in public) regarding anything having to do with sex. (In fact, some reading this will shudder at my bringing it up in a blog for students or professors . . . if they've even read this far. Click here if you have a problem with it.)

Want to know more, so your A&P lecture is up to date with the latest trends in pop culture?

Try this straightforward . . . and easy to understand . . . article from Scientific American.

OUCH! Can you really break your penis?

You'll learn a lot of useful A&P, you'll be ready for the inevitable classroom discussion on this topic, and you'll be all set for a future career as a TV/movie consultant after you retire!

Want to know even more useful (and possibly career-enhancing) facts related to the sex organs? Then check out this book:
Skin Flutes & Velvet Gloves: A Collection of Facts and Fancies, Legends and Oddities About the Body's Private Parts

Fun fact. . .
The television show Grey's Anatomy is a word play on the title of a famous medical anatomy text by Henry Gray called Gray's Anatomy. Notice the difference in spelling. Originally published over 150 years ago (1858), the current edition remains a leader among the best available references to the human body (and now comes in many different variations to suit different needs). See my recent blog post The Anatomist for more.

Sad pucker

It's not alway easy for beginning students to remember which organs are peritoneal and which are retroperitoneal.

One easy way to remember which abdominopelvic organs are retroperitoneal is to use a mnemonic such as SAD PUCKER:

• S = Suprarenal (adrenal) glands
• A = Aorta/Inferior Vena Cava
• D = Duodenum (second and third segments)
  
• P = Pancreas
• U = Ureters
• C = Colon (ascending and descending only)
• K = Kidneys
• E = Esophagus
• R = Rectum

Or instead, Ursula Uses Kids to Deliver All Lemon Pies except Sue’s Tasty Crust

• Ureters
• Urinary bladder
• Kidneys
• Duodenum
• Adrenal glands
• Large intestine
• Pancreas
• exept (not retroperitoneal) Sigmoid and Transverse Colon

[NOTE: these mnemonics are adapted from a Wikipedia entry]

Growing a new prostate

This letter in the 22 October 2008 advanced online issue of of Nature caught my eye . . .

Scientists at Genentech, Inc. have identified an adult stem cell type in the male prostate that can can be transplanted and generate a new prostate in the donor!

Generation of a prostate from a single adult stem cell
Kevin G. Leong, et al.
Nature advance online publication 22 October 2008 | doi:10.1038/nature07427
[Original article; summary is free]

'New prostate' grown inside mouse
BBC News online, accessed 24 October 2008
[Summary of research and its context; cool image of a prostate cancer cell]