Category Archives: science

Maggots Regain Medical Respect

MerckSource carries an AP report on reviving the use of maggots to disinfect open sores.

TOKYO – Dr. Hideya Mitsui’s patients were in trouble – diabetes-triggered lesions on their feet weren’t responding to antibiotics, and amputation was the next step.

So Mitsui turned to an unsightly remedy he says has never used before in Japan: maggots.

The maggots, once used by Australian Aborigines and Native Americans in the days before antibiotics, have been credited with curing three of the five cases Mitsui was treating. Two others are still being treated.

“This old therapy is great,” said Mitsui, a heart surgeon at Okayama University Hospital in western Japan. He started the treatment in March.

Under the therapy, maggot larva are placed in the wound, where they dissolve dead infected tissue and secrete a substance that disinfects the lesion.

Mitsui leaves the larva in the lesion for a week, then replaces them with fresh maggots. The process is repeated about three times over two weeks.

Maggot therapy was used in the United States but was largely discontinued with the growing popularity of antibiotics in the 1940s. Mitsui said the therapy is still used in Britain.

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I Think, Therefore I’m an Old Polecat

Virginia Postrel links to a University of Rochester study on ferret brain activity. (What’s the difference between a ferret and a polecat? “Taxonomically speaking — there is no difference. Both are currently classified as Mustela putorius.“)

There’s an old myth that we only use 10 percent of our brains, but researchers at the University of Rochester have found in reality that roughly 80 percent of our cognitive power may be cranking away on tasks completely unknown to us. Curiously, this clandestine activity does not exist in the youngest brains, leading scientists to believe that the mysterious goings-on that absorb the majority of our minds are dedicated to subconsciously reprocessing our initial thoughts and experiences. The research, which has possible profound implications for our very basis of understanding reality, appears in this week’s issue of the journal Nature.

“We found neural activity that frankly surprised us,” says Michael Weliky, associate professor of brain and cognitive sciences at the University of Rochester. “Adult ferrets had neural patterns in their visual cortex that correlated very well with images they viewed, but that correlation didn’t exist at all in very young ferrets, suggesting the very basis of comprehending vision may be a very different task for young brains versus old brains.”

A second surprise was in store for Weliky. Placing the ferrets in a darkened room revealed that older ferrets’ brains were still humming along at 80 percent as if they were processing visual information. Since this activity was absent in the youngsters, Weliky and his colleagues were left to wonder: What is the visual cortex so busy processing when there’s no image to process?

Initially, Weliky’s research was aimed at studying whether visual processing bore any resemblance to the way real-world images appear. This finding may help lead to a better understanding of how neurons decode our world and how our perception of reality is shaped.

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Environmentally Determined Deforestation

UCLA biogeographer Jared Diamond and U. of Hawai‘i anthropologist Barry Rolett have published an article in Nature (23 September 2004) about pre-European deforestation on Pacific Islands. Those familiar with Diamond’s Guns, Germs, and Steel (W. W. Norton, 1996) will not be surprised that environmental determinism plays a major role.

The pair, whose collaboration started after Diamond visited Hawai‘i as part of UH’s Distinguished Lecture Series in 2000, coded Pacific islands for the amount of deforestation and forest replacement based on the observations of early European visitors. They used four types of statistical analysis to weigh nine variables. Predisposing islands to deforestation are

  • low rainfall (which slows plant growth and increases risk from fire)
  • higher latitudes (where cooler temperatures slow plant growth)
  • age (because soil nutrients are lost over time)
  • distance from sources of material that replenish soil nutrients (volcanic ash fallout and Central Asians dust)
  • low elevation (mountains rains provide water and capture atmospheric dust, and streams carry nutrients to the lowlands)
  • small and isolated [Arrgh! They mean “small size and isolation”!] (limiting diversity of tree species and inaccessible areas and reducing trading and raiding as options for obtaining resources)

While they don’t dismiss the impact of Polynesian societal practices on deforestation, Rolett and Diamond conclude that Easter Island’s collapse had less to do with improvident actions than the fragile environment. They hope to see their analysis further refined and extended to other societies and locations.

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Beriberi, White Rice, and Vitamin B

Danny Yee has posted an interesting review of Beriberi, White Rice, and Vitamin B by Kenneth Carpenter (U. California Press, 2000).

As we now know, beriberi is caused by nutritional deficiency of thiamin (vitamin B1), most commonly associated with reliance on polished white rice. But establishing this, isolating the “vitamin” responsible, and implementing appropriate public health measures was a long and complex process. In Beriberi, White Rice, and Vitamin B Kenneth Carpenter makes of it a fine “medical detective story”….

Regimented groups such as soldiers, sailors, and prisoners were common sufferers; with standardised diets and centralised records, these were also the target of most studies. The Japanese Navy largely eliminated beriberi (kakk&eacute) around 1895; naval doctor Kanehiro Takaki thought protein deficiency was the problem, but the measures he implemented worked anyway. The army, however, was convinced beriberi was an infectious disease and suffered over 90,000 cases in the 1905 war against Russia.

The name “beriberi” originated in Southeast Asia, where it had become widespread with the colonial introduction of machine milling of rice. Work on the disease was done by the Dutch in Java, most notably by Christiaan Eijkman, who shared the 1929 Nobel prize for studies using chickens, and by the British in Malaysia and the Americans in the Philippines. Some kind of consensus was reached at the first meetings of the Far Eastern Association of Tropical Medicine in 1910 and 1912….

There were disagreements over how much thiamin is needed, whether extra amounts had any beneficial effect, and what public health measures should be implemented. There were various modifications to the production and preparation of rice in Japan and Southeast Asia, while the United States and Britain made addition of thiamin to white bread compulsory during WWII. Australia mandated enrichment of bread and flour in 1991, but in 1998 was still considering the compulsory addition of thiamin to beer, to reduce the incidence in alcoholics of Korsakoff’s syndrome.

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Of Mice and Rats

Can you tell a mouse from a baby rat? After reading these tips, I correctly identified 12 out of 12. (And I didn’t have to count the nipples!) Can you tell the relatively civilized Black Rat (Rattus rattus) of the Pacific Islands from the marauding imperialist Norwegian Rat (Rattus norvegicus), which has conquered most of Eurasia and North America? Do you know how to launder your pet rat? It’s all at ratbehavior.org.

via Language Hat, who linked to the authoritative Rat-English, English-Rat Dictionary.

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Anti-Vaccination Fever

The January 2004 issue of Skeptical Inquirer ran a report by William John Hoyt, Jr., under the title “Anti-Vaccination Fever: The Shot Hurt Around the World”:

Sensationalist media, religious fanatics, and alternative medical practitioners fanned the fires created by questionable research to spawn worldwide epidemics of a disease that had almost been forgotten.

“A poignant television story of a victim of a rare reaction to a vaccine can render invisible the vast good brought about by this same vaccine.” — John Allen Paulos

When pertussis takes hold, the infected person makes horrid, whooping sounds as he inhales. When he gets a chance to inhale. Which isn’t often during the torturous “paroxysmal phase,” characterized by sudden attacks of repetitive, severe coughing. The disease’s Latin name, pertussis, translates as “intensive cough.” But whooping cough, the common name, does a far better job of describing the unique whooping sound the disease’s victim makes when, finally, he gets a chance to breathe….

You have probably imagined an adult victim while reading thus far. In fact, before an effective vaccine became available, pertussis had been a worldwide leading cause of infant deaths. Before the 1940s, it was a major cause of infant and child morbidity and mortality in the U.S. (CDC 2002). From 1890 to 1940, in New South Wales, whooping cough killed more children under five than diphtheria. It was second only to gastroenteritis as a cause of infant deaths (Hamilton 1979)….

Fear and Loathing on the Vaccine Trail

In 1906, researchers discovered that the Bordatela pertussis bacterium caused pertussis. Within twenty years of that discovery, the first whole-cell pertussis vaccine was developed (Research Defence Society 1999). After two decades of testing and refinement, many countries accepted varying versions of a whole-cell pertussis vaccine, established vaccination protocols, and began to vaccinate their citizens. Many of the vaccine manufacturers produced a combined diphtheria-tetanus-whole cell pertussis (DTP) vaccine.

For most countries, as vaccination coverage increased, both the frequency and severity of pertussis epidemics markedly declined. Ironically, this success actually may have been the vaccine’s undoing, as presaged in this pointed 1960 British Medical Journal commentary: “When immunization results in the virtual elimination of a disease it is inevitable that some will question the continued need for routine inoculation of all infants” (Editors 1960).

The first hint of a problem came from Sweden in 1960, less than ten years into its vaccination program. Sweden had previously seen pertussis incidence rates as high as nearly 300 per 100,000. By 1960, the incidence rates were merely a third of that and falling (Gangarosa et al. 1998). It was at this time that Justus Ström, an influential Swedish medical leader, questioned the continuing need for pertussis vaccines. In his British Medical Journal paper, he claimed pertussis was no longer a serious disease because of economic, social, and general medical progress. Furthermore, he cited thirty-six cases of neurological conditions that he attributed to the whole cell pertussis vaccine, calculating an alarming neurological complication rate of 1 in 6,000 (Ström 1960)….

Then in the United Kingdom, in 1974, Kulenkampff and his colleagues published a paper citing another thirty-six cases of neurological reactions that they attributed to the whole cell pertussis vaccine. The paper’s evidence was weak on several fronts acknowledged by the authors. They clearly stated they “do not know either the prevalence of natural infection or the frequency of inoculation encephalopathy (brain diseases resulting from vaccination) in the population we serve” (Kulenkampff et al. 1974). And they noted that “in as many as a third of our patients there were contraindications to inoculation with pertussis vaccine, in that there was a previous history of fits, or family history of seizures in a first-degree relative; reaction to previous inoculation; recent intercurrent infection; or presumed neurodevelopmental defect” (Kulenkampff et al. 1974).

Despite the authors’ appropriately cautious approach to their paper, the anti-vaccination advocates seized upon it, and the media ran with it. Soon after the paper’s publication, British television aired a program on the whooping cough vaccine. Focusing on the anecdotal evidence of terrible adverse reactions supposedly caused by the vaccine, it presented little of the clear good the vaccine had done historically.

The negative press and television coverage persisted for years….

Brief summaries and graphs then detail how pertussis infection rates spiked to epidemic levels in countries where panicked medical establishments abandoned or severely cut back on vaccination programs.

Returning to the Status Quo Ante Botchum

The epidemics shocked many of the nations that experienced them, although official and public responses have varied. Many countries introduced acellular pertussis vaccine as a “safer” alternative to the whole-cell vaccine. Some have also tried to control the problem by introducing more vaccination boosters to the protocol. But other countries, those whose vaccination programs were unaffected by anti-vaccination movements, haven’t experienced these epidemics at all. These countries include Portugal, Hungary, Norway, the former East Germany, Poland, and, until recently, the U.S.

Japan’s reaction to its epidemic was swiftest and strongest. By 1981, Japan resumed vaccination with an acellular pertussis vaccine and pertussis incidence rates returned to their pre-fiasco levels. The United Kingdom’s vaccine uptake rate began slowly climbing, and by the 1990s reached levels exceeding those prior to the hysteria. English and Welsh pertussis incidence rates declined accordingly.

Sweden, however, remains plagued with high pertussis rates. As recently as 1996, and despite continuing epidemics, Sweden had yet to resume vaccinations (Cherry 1996). Australia’s efforts to halt pertussis continue to be thwarted by a passive anti-vaccination movement. The 2001-2002 epidemic bears witness to that. The Russian Federation has also failed to regain control and today has one of the highest pertussis incidence rates in the developed world.

Distorted numbers, confusion of correlation with causation, and statistical innumeracy certainly played roles in this sad story. Sensationalist media campaigns fanned the glowing embers. But in each of the countries that experienced the raging fires of epidemics there were other forces at work. Most prominent in passive anti-vaccination movements were religious groups whose opposition was based on religious or moral grounds. Prominent in both passive and active anti-vaccination movements are followers and practitioners of homeopathy, chiropractic, and natural and alternative medicine (Gangarosa et al. 1998)….

When anti-vaccination alarm takes hold–characterized by sudden attacks of the media, mistaken researchers, fervent religious groups, and alternative medicine quacks–the infected society begins to make horrid, whoppingly bad decisions. There is, as yet, no Latin name for this peculiar social disease.

via Arts & Letters Daily

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