Author Archives: jaevans

Building a Smarter Mouse

Courtesy flickr user Steve Beger Photography (Beger.com Productions) via Creative Commons

From the annual meeting of the American Academy of Neurology in Toronto:

If you suspect that the mice living in your home are too smart for their own good, you haven’t seen anything yet. Make way for mice with humanized brains that have been proven to learn faster than do their normal counterparts.

In his Presidential Lecture at the meeting, Dr. Steven Goldman of the University of Rochester, N.Y., engrossed listeners with a story of his research team’s use of human glial progenitor cells that had been isolated from the brains of second trimester human fetuses that had been aborted because of premature rupture of the membranes. These glial progenitor cells have the abilityto transform into astrocytes and oligodendrocytes, that latter of which produce the myelin sheath that wraps around the axons of neurons to speed electrical signals from neuron to neuron. Mice that are born with oligodendrocytes that cannot produce myelin—called shiverer mice—experience uncontrollable body and limb convulsions that cause progressive neuronal degeneration and the development of continual, uncontrollable seizures (status epilepticus) that kill them.

Dr. Goldman and his colleagues found that infusions of human glial progenitor cells into newborn shiverer mice could rescue them to a nearly normal state and a normal life span. The transplanted glial cells in these mice differentiated into oligodendrocytes that produce myelin and astrocytes that wrap themselves around the synapses of the murine neurons. These human astrocytes almost completely replace the mice’s own astrocytes after 13 months. Such a treatment could potentially be used to treat myelin disorders in children.

These results are amazing in themselves, but Dr. Goldman’s research gets even more interesting.

One of the striking differences in the brains of mice and humans is the larger size and greater complexity of human astrocytes in comparison to their murine counterparts. Dr. Goldman’s research team demonstrated that human glial progenitor cells infused into the brain of newborn normal mice also led to a gradual replacement of murine glial cells with human glial cells. These mice need only one trial to establish a fear response to a noise associated with a subsequent electrical shock, compared with many repeated trials in normal mice.

Dr. Goldman pointed out that his findings aren’t entirely new. Go and watch The Secret of NIMH.

–Jeff Evans (@jeffaevans on Twitter)

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Filed under IMNG, Neurology and Neurological Surgery

New Obesity Recommendations Face Uphill Battle

Courtesy of Flickr user ktheory

There is now enough evidence to recommend screening for overweight and obesity in children aged 6 years and older and enough evidence backing the efficacy of behavioral interventions of at least moderate intensity, according to the U.S. Preventive Services Task Force. (See story.)

Will this recommendation pack a big enough punch to kick-start a movement toward more screening and greater acceptance and awareness of the efficacy of behavioral interventions? It looks like it will be an uphill battle, if a new survey of members of the American Academy of Pediatrics gives a true indication.

The survey of 677 primary care clinicians in active practice revealed that only 52% assess BMI percentile for children older than 2 years and only 23% said they believe that there are good treatment strategies for overweight. Less than half said they are able to make referrals to interventional programs.

It also was notable that clinicians who are familiar with American Academy of Pediatrics guidelines on obesity screening and treatment were more likely to use BMI percentiles in their care and more likely to feel prepared to counsel patients.

Dr. Ned Calonge, the chair of the USPSTF, recognized that many clinicians won’t be able to offer referrals to weight management centers, but he said with greater recognition of the value of screening and the efficacy of treatment, greater availability of referral services and insurance coverage will hopefully follow. That will be key because 69% of providers in the survey said that insurance does not cover weight management programs, and only 15% reported that they can bill for overweight counseling and treatment separate from well-child visits.

Jeff Evans (@jeffaevans on Twitter)

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Filed under Endocrinology, Diabetes, and Metabolism, Family Medicine, Pediatrics, Primary care, Uncategorized

New Genetics Clinical Support Tool in Development

courtesy of Flickr user mujitra

courtesy of Flickr user mujitra

From the National Coalition for Professional Education in Genetics annual meeting, Bethesda, MD.

In Fall 2010, primary care clinicians may get their first really accessible point-of-care clinical decision support tool to help with the diagnosis, treatment, and management of patients with genetic conditions. The tool, a Web site called GeneFacts, aims to provide busy clinicians with “concise, not complete” information about genetic conditions they are searching for in about 2 minutes, said Dr. Leigh LoPresti, a family medicine physician at the Medical College of Wisconsin, Milwaukee, who is working with the National Coalition for Health Professional Education in Genetics (NCHPEG) to create the Web site.

At the NCHPEG annual meeting, Dr. LoPresti presented a rough look at the open-access Web site, which currently houses five single-gene diseases “that we thought would be important in primary care,” including cystic fibrosis, neurofibromatosis-1, and hemochromatosis. GeneFacts will provide guidance on 30-35 diseases when it is launched, “but obviously it has to grow a whole lot from there,” Dr. LoPresti said.

Its content will be coauthored by a non-geneticist provider to ensure its accessibility and a geneticist to ensure its accuracy. In addition to single-gene diseases, GeneFacts will contain information on pharmacogenetics and genetic factors related to common diseases.

Each entry will fill a standard template that houses “key points,” a navigation bar, a body map to show affected areas, and “access buttons” that show only sections that are relevant to a particular situation. The information will be presented in a layered format to click through for greater depth, featuring algorithms, tables for more complex data, an embedded glossary, and links to other resources.

In the meantime, health professionals (and consumers) can judge the value of the content of other medical reference Web sites, brochures, and booklets by using Trust It Or Trash It?, a Web site developed by the Genetic Alliance, NCHPEG, and five other partners. It is funded by the Centers for Disease Control and Prevention.

-Jeff Evans (6:10 p.m. ET, Sept. 25, 2009), @jeffaevans on Twitter

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Filed under Family Medicine, Genomic medicine, Internal Medicine, Medical Genetics, Primary care

Guidelines Issued for Treating Transsexual Patients

Courtesy of Photobucket user stsh90 (Creative Commons)

Courtesy of Photobucket user stsh90 (Creative Commons)

From the annual meeting of the Endocrine Society, Washington:

On June 12, the Endocrine Society released its first clinical practice guidelines on the care of transgender patients. The release of the guidelines (Endocrine Treatment of Transsexual Persons) marks a major point in the recognition of the need for long-term medical care and the development of skills needed to care for such patients.

Multidisciplinary collaboration is essential in the care of transsexual persons because successful outcomes depend uniquely on the replacement of normal physiology as well as physical, social, and legal transformations, said Dr. Wylie C. Hembree, chair of the eight-member task force that wrote the guidelines. Dr. Hembree said that guidelines are necessary for several reasons.

First and foremost is the relatively large population that is in need of appropriate care. From 1973-2008, the average incidence of transsexualism has been estimated to be 1 of every 8,000 people born outwardly male and 1 of every 24,000 people born outwardly female. This totals about 4,000 adolescents and 25,000 adults in the United States, Dr. Hembree said.

“Although utilization of health care providers has come to the fore more so in reducing some of the risk behaviors of transsexual persons, it does not result in adherence to WPATH [World Professional Association for Transgender Health] standards or recommendations,” he said.

“Patients know more about their care, routinely, than do the doctors who are treating them.”

In addition, no medications are approved by the U.S. Food and Drug Administration for the treatment of transsexualism.

–Jeff Evans (@jeffaevans on Twitter)

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Filed under Endocrinology, Diabetes, and Metabolism, Psychiatry, Surgery, Uncategorized

Where Neurologic Diagnostic Expertise Meets Psychiatric Therapeutic Skills

Image courtesy of Flickr user cliff 1066 (creative commons)

Image courtesy of Flickr user cliff 1066 (creative commons)

From the Second International Conference on Psychogenic Movement Disorders and Other Conversion Disorders, Washington:

How do you accurately diagnose and treat a patient with an unusual movement disorder that does not appear to have any objective cause? Neurologists and psychiatrists gathered last week to discuss these and other related disorders at the L’Enfant Plaza Hotel, which is one of the closest hotels to the cherry blossoms at the ongoing National Cherry Blossom Festival.

Psychogenic movement disorders (PMDs) are spectrum conditions featuring abnormal movements that have no known “organic” cause but are not consciously mediated. These movements include tremor, myoclonus, dystonia, paralysis, and paroxysms (see the video on psychogenic nonepileptic seizures). They are thought to be a type of conversion disorder, in which a person’s psychological and emotional reaction is expressed through neurologic symptoms with no identifiable tissue pathology or nerve dysfunction. The movements may be bizarre and exhibit false neurologic signs. They can sometimes occur concomitantly with identifiable organic neurologic disease, including movement disorders, as well as additional psychiatric disturbances. In fact, many patients with PMD have a comorbid psychiatric condition or have a history of traumatic experience in the distant or recent past that may have served as a trigger to initiate the behavior.

No one is sure why individuals express a particular movement and not others, although there is evidence to suggest that some patients, especially adolescents, may unconsciously “model” the movement from examples they have seen in friends or relatives. Unlike movement disorders with objective evidence of disease or injury, these movements may go away with distraction and may be entrained to match the rhythmic movement of another body part or a sound.

Neurologists specializing in movement disorders see these patients most often through referrals, some of whom go on to treat or at least follow-up with patients. Some patients may completely resolve their symptoms, at least in the short-term, with mere suggestion (potentially while under hypnosis) or with a carefully arranged and fully consented placebo treatment. There is no gold-standard treatment, although psychotherapy in its various forms is often prescribed, if it is accepted by the patient.

And that’s the major conundrum that specialists face in diagnosing and treating these patients.  The patients, most of whom are female, may have been seen by many physicians who have been unable to help them or have prescribed inappropriate medications or surgical interventions to improve their condition, often without having first conducted a full differential diagnosis. These patients have often been previously diagnosed with an organic cause to their movements, and may be taken aback when told that their symptoms are psychogenic. That’s why experts agree the presentation of a PMD diagnosis to a patient is critical and must be individually tailored. Of course, neurologists must differentiate patients with a PMD from those with a factitious disorder or those who are malingering.

One of the experts in PMD, Dr. Jon Stone of Western General Hospital, Edinburgh, recently launched a Web site, Functional and Dissociative Neurological Symptoms: a patient’s guide, to help patients and others in understanding the manifestations of symptoms that occur along the spectrum of these conditions.

–Jeff Evans (video courtesy of YouTube user ETPepilepsyvideos)

 
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Filed under Neurology and Neurological Surgery, Psychiatry

Are U.S. Training Programs Producing Incompetent General Surgeons?

 From the annual meeting of the Central Surgical Association, Sarasota, Fla., March 6:

In his presidential address at the meeting today, CSA president Dr. Richard H. Bell painted a worrisome picture about the training of general surgeons in the United States. Citing concerns that he had heard from fellowship program directors about the lack of competency in graduating general surgery residents, he decided to see if there was evidence to support their stories.

Dr. Bell, assistant executive director at the American Board of Surgery, noted that research into activities that require long-term psychomotor learning to master, such as sports, chess, and performing surgery, suggests surgeons gain competency after about 10,000 hours of practice. But the average general surgery resident in the era of the 80-hour week has operated for about 1,150 hours by the end of their 5-year residency, he said.

In one survey that Dr. Bell cited, general surgery program directors were asked to pick which of about 230 general surgery procedures that they regarded as essential to learn in a training program. A total of 121 procedures were selected by at least half of the directors. Of these 121 procedures, the one most often performed by residents in 2005 (the last year for which data are available) was laparoscopic cholecystectomy, with a mean of 84 performed by graduation. There is a steep drop off in mean cases performed per resident as one goes down the list of the directors’ selected procedures, such that the mean number of cases performed for the last 60 or so procedures is less than 10 per resident.

Dr. Bell highlighted parathyroidectomy as an example in which residents with large numbers of cases skewed the results. In 2005, residents performed a mean of nearly 10 parathyroidectomies. However, the median number of cases was eight, while the mode, the most frequently occurring number of cases, was only four. Dr. Bell said that it would be hard to argue that a graduating general surgeon with only four parathyroidectomy cases under his or her belt would be considered competent to perform the procedure.

He also noted that the citation that is issued to training programs by the Surgery Residency Review Committee of the Accreditation Council for Graduate Medical Education when a program’s total case logs for an operative procedure fall below the 10th percentile does not relate very much to how well particular programs are training residents. For many procedures, the difference between the 10th percentile and the 30th or 50th percentiles may be as little as one or two cases.

Some people claim that surgical skills gained for performing one procedure can be transferred to another, Dr. Bell said. While this may be true of technical skills, research shows that when surgeons operate, they think in discrete modules for each specific operation and check each step of a procedure against their previous experiences with that procedure. They do not think in terms of a group of operative skills that can be transferred from one specific procedure to another.

Dr. Bell’s recommendations for remedying the situation included more careful documentation of residents’ operative cases, the formation of a national operative simulation program in general surgery residency programs across the United States to help in the training of residents, and the development of standardized and validated means to evaluate surgical faculty members on their teaching and training of residents.

–Jeff Evans

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Filed under Surgery, Uncategorized

Liver Donation After Cardiac Death Still A Work in Progress

From the annual meeting of the Central Surgical Association, Sarasota, Fla.:
Surgeons transplanted more than 6,000 donor livers into recipients in the United States in 2007, but that number may not seem so impressive when you consider that more than 16,000 patients remained on the Organ Procurement and Transplantation Network‘s waiting list and more than 2,000 people died waiting on it in that year.
Most of those livers have been procured from donation after brain death (DBD) donors, but the percentage of livers that have been obtained from donation after cardiac death (DCD) donors has increased more than 10-fold in the past decade to 5.8% in 2006. And although recipient survival is now frequently reported in studies to be similar with either type of donation, the rates of re-listing, re-transplant, and resource utilization are higher in DCD recipients than in DBD recipients, according to Dr. Anton Skaro.
Dr. Anton Skaro

Dr. Anton Skaro

“Beyond survival metrics and basic complication rates, the impact of ischemic cholangiopathy and biliary complications in general have not been studied with regard to their impact on patients and society,” said Dr. Skaro of the division of organ transplantation at Northwestern University, Chicago.

In a study of 32 DCD and 237 DBD recipients of primary liver transplants at the university during 2003-2008, he and his colleagues found that DCD recipients had signficantly higher rates of biliary complications (53% vs. 22%) and ischemic cholangiopathy (38% vs. 2%) than did DBD recipients. Biliary complications were the cause of nearly 70% of all re-transplantations among the DCD recipients.

Hospital readmissions and invasive biliary tract procedures also occurred significantly more often among patients who had ischemic cholangiopathy than in those who did not. After adjusting for recipient confounding variables, the risk of ischemic cholangiopathy was independently associated with DCD donor age greater than 40 years and the ratio of donor-to-recipient heights.

In an interview, Dr. Skaro said that finding additional predictors for poor outcomes, particularly biliary complications and ischemic cholangiopathy, should help centers to match recipients with appropriate donor livers. This may require organ allocators to design ways of detecting patients with these complications that will then address whether they need an ‘upgrade’ in their Model for End-Stage Liver Disease (MELD) score in order to give them better access to re-transplantation.

“I think transplant centers need to have the ability go further down the list to preferantially transplant recipients who are ‘desperate’–those that have a low MELD score but are affected by significant disease burden that isn’t reflected in that MELD score,” he said.

—Jeff Evans

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Filed under Gastroenterology, Surgery, Transplant Medicine and Surgery