Category Archives: Noteworthy

Von Pettenkofer und die Cholera

Die neue Pettenkofer Biographie (“Max von Pettenkofer: Pionier der wissenschaftlichen Hygiene (Kleine Bayerische Biografien”) von Wolfgang G. Locher lässt doch einige Fragen offen, wenn das komplette Privatleben auf nur 3 Seiten (S. 31-33) abgehandelt wird.

Aber auch von der wissenschaftlichen Seite hätte man sich mehr Informationen gewünscht. Warum kann nur ein so begabter Chemiker so lange eine falschen Theorie vertreten?

Im Zusammenhang mit dem berühmten Zwiestreit mit Robert Koch über die Ursache der Cholera schluckte Pettenkofer am 7. Oktober 1892 sogar eine Kultur von Cholera-Bakterien. Er kam mit einer heftigen Diarrhöe davon  … erheblich größerer Bedeutung für die Entstehung einer Krankheit als die bloße Anwesenheit von Krankheitserregern. Allerdings irrte er insoweit, als er ein bestimmtes „contagiöses Element Y“ (Miasma) annahm, das – gleich einer chemischen Reaktion – die Entstehung einer Krankheit erst ermöglichte

Sind es verschiedene Cholera-Erreger? In der Tat, es gibt über 200 Serogruppen wovon nur O1 und O139 epidemisch auftreten. O1 El Tor wird wohl immer wieder aus Asien nach Afrika eingeschleppt. Und von Pettenkofer lag mit seine Miasmen also nicht völlig daneben, wenn Weil und Ryan 2018 Recht haben

V. cholerae persists in the environment by associating with zooplankton or copepods, and for this reason has classically been considered ineradicable.
The current seventh pandemic has persisted for more than 50 years, and has been punctuated by episodes of emergence and re-emergence of cholera in areas lacking modern sanitation.

Man müsste also mal die historischen Outbreaks auf Planktonvorkommen untersuchen, denn nur wo es ein Reservoir gibt, kann die Cholera Ausbruch kommen, wobei auch hochinfektiöse Patienten als Reservoir fungieren.

Es bleibt die Frage, ob esdenn  genetisch bedingte Resistenzen gibt?

Many risk factors for infection are based on fecal- oral spread of V. cholerae. Well established additional factors contributing to susceptibility include lack of previous exposure to V. cholerae, blood group O status, and low gastric pH. Several genetic polymorphisms have been associated with susceptibility to disease in the last decade, and this work has been extended using whole genome sequences from humans exposed to V. cholerae over several centuries. In this study, the genomes of ethnic Bengalis from Bangladesh were enriched for … the nuclear factor kappa-light- chain-enhancer of activated B cells.

Pettenkofer hat damit doch wohl doch recht behalten, wir müssen ihm mal ein paar Blumen auf das Grab lege, Feld 49 auf dem alten südlichen Friedhof unterhalb des Sendlinger Tores.

Ratatouille der Gedanken

Silvia Strahm spricht mir aus der Seele wenn sie in ihrem neuesten Beitrag auf fragt, was bleibt denn vom Denken, Nachdenken, Hinterfragen in Zeiten der Meinungen, der Informations- und Wissensflut?

Ich war einmal ein denkender Mensch, vor vielen Jahren. Ich hatte viel gelernt, über alles Mögliche und über viel Unmögliches auch, habe Schul- und andere Weisheiten erworben, nachgedacht über das Leben und die Welt im Allgemeinen und im Besonderen. Das war anstrengend, beglückend, manchmal schwindelerregend, aber das Werkzeug hatte ich beisammen, alles war da, dem, was geschah, geschehen war und noch im Gang, ordnend beizukommen.
Geblieben davon ist das Hantieren. Mit den Werkzeugen. Die habe ich behalten. Immer wieder etwas geputzt und geschliffen, aber im Grossen Ganzen sind es noch dieselben.
Geändert hat sich trotzdem alles.

Continue reading Ratatouille der Gedanken

Bullet points for future allergy research

Maybe this is a difficult task – defining an agenda for future research. Here are some thoughts as we don’t know the reasons for the allergy epidemic even after 100 years of research. And we don’t have any cure yet, there is some relief of symptoms and there are some limited curative efforts but we don’t have any real understanding of what is going on. The following research areas may therefore be identified in NON-therapeutic research: Continue reading Bullet points for future allergy research

Finally! 23 and the FDA warning

Quite some time passed already since my last post (to be exact, more than 5 years) but now there are good news. The FDA issued a warning letter on the 22nd

… The Food and Drug Administration (FDA) is sending you this letter because you are marketing the 23andMe Saliva Collection Kit and Personal Genome Service (PGS) without marketing clearance or approval in violation of the Federal Food, Drug and Cosmetic Act (the FD&C Act) … However, even after these many interactions with 23andMe, we still do not have any assurance that the firm has analytically or clinically validated the PGS for its intended uses … Therefore, 23andMe must immediately discontinue marketing the PGS until such time as it receives FDA marketing authorization for the device …

The response is quite flimsy. Yes, there may be negative side effects of genetic testing and of course tests need to validated first. Slate may be correct that the FDA’s battle with 23andMe won’t mean anything in the long run but now at least, we are set back to science, yea, yea.

LIMIT TO 5! What about a maximum of 5 papers per year per scientist?

Undoubtly, there is an avalanche of poor research – as the Chronicle wrote last June, “we must stop the avalanche of low-quality research

the amount of redundant, inconsequential, and outright poor research has swelled in recent decades, filling countless pages in journals and monographs. Consider this tally from Science two decades ago: Only 45 percent of the articles published in the 4,500 top scientific journals were cited within the first five years after publication. In recent years, the figure seems to have dropped further

Also Genomeweb writes

Pedro Beltrao at the Public Rambling blog says there never seems to be enough time to keep up with all the literature researchers keep churning out. In 2009, 848,865 papers were added to PubMed, he says — that’s something like 1.6 papers per minute.

Continuing a discussion Continue reading LIMIT TO 5! What about a maximum of 5 papers per year per scientist?

Science success sucks (sometimes)

Leo at zenhabits has a great new piece:

Why I don’t care about success. ‘Try not to become a man of success, but rather try to become a man of value.’ (Albert Einstein)
A lot of people in my field write about how to be successful, but I try to avoid it. It’s just not something I believe is important. Now, that might seem weird: what kind of loser doesn’t want to be successful?
Me. I’m that loser. Continue reading Science success sucks (sometimes)

A longe fuse

Mutation accumulation in the human genome is a largely neglected research field. Most mutations have a very small effect (if any) and may be compensated by environmental improvements. I have already argued in that way in the 2003 Triple T paper and will reiterate it soon in PLOS medicine (just found that James Crow 1997 in PNAS and 2000 in nat gen rev had the same opinion). In principle, the improvement of sanitation and better medical care is leading to a retention of mutations that would be otherwise subject of purifying selection.
Another important factor seems to be the increase of parental age in Western societies. A 20 year old man had about 150 chromosome replications while a 40 year old had about 610 replications. To count the number of your somatic mutations, you need to add all events of your lifetime plus the age of your father at birth minus 9 months … Even with the high fidelity of polymerases, DNA replication remains an error prone process leading eventually to an increase of germline mutations (as may be seen with achondroplasia, Apert syndrome, neurofibromatosis and prostate cancer). With the increasing age of fathers we are now nearly doubling the absolute number of mutations every generation – and we keep them in the pool in contrast to previous centuries. Crow in PNAS 1997 even said

I do regard mutation accumulation as a problem. It is something like the population bomb, but it has a much longer fuse


Addendum 20 Nov 2013

In another post, I detailed the 3,93 figure derived from cancer tissues. The best human estimate at the moment is in this Cell paper that shows a rate between 2.0 and 3.8 x 10^-8 cells. Sperm sequencing may not represent a good model as there are so many degenerate cells.

Is religion a natural phenomenon?

I do not want to discuss the rather polemic view of Daniel Dennetts “Breaking the spell” or promote other books of the new secularism. The Guardian digital edition writes on 29th Oct 2006

Secularism is suddenly hip, at least in the publishing world. A glut of popular science books making a trenchant case against religion have soared up the bestseller lists both here and in America. The phenomenon represents a backlash against a perceived rise in religious fundamentalism and recent crazes for ‘spirituality’ by way of books such as The Da Vinci Code. Secularists are now eager to show that the empiricism of science can debunk the claims of believers.

More interesting is the question if human morality is an inborn trait or not. Nicholas Wade has a nice essay in the NYT:

Marc D. Hauser, a Harvard biologist, has built on this idea to propose that people are born with a moral grammar wired into their neural circuits by evolution. In a new book, “Moral Minds” (HarperCollins 2006), he argues that the grammar generates instant moral judgments which, in part because of the quick decisions that must be made in life-or-death situations, are inaccessible to the conscious mind. People are generally unaware of this process because the mind is adept at coming up with plausible rationalizations for why it arrived at a decision generated subconsciously. Dr. Hauser presents his argument as a hypothesis to be proved, not as an established fact. But it is an idea that he roots in solid ground, including his own and others’ work with primates and in empirical results derived by moral philosophers.

I renember also an article by Roger Higfield in the Washington Times (24th March 2003) than unfortunately vanished from the internet:

Scientists are hunting for a “God gene” that underpins our ability to believe. The idea of genes linked with beliefs does not look far-fetched, given the influence of genetics on the developeing brain.

Higfield is refering to an empirical twin study:

To investigate the heritability of religiousness and possible age changes in this estimate, both current and retrospective religiousness were assessed by self-report in a sample of adult male twins (169 MZ pairs and 104 DZ pairs, mean age of 33 years). Retrospective reports of religiousness showed little correlation difference between MZ (r=.69) and DZ (r=.59) twins. Reports of current religiousness, however, did show larger MZ (r=.62) than DZ (r=.42) similarity. Biometric analysis of the two religiousness ratings revealed that genetic factors were significantly weaker (12% vs. 44%) and shared environmental factors were significantly stronger (56% vs. 18%) in adolescence compared to adulthood. Analysis of internal and external religiousness subscales of the total score revealed similar results. These findings support the hypothesis that the heritability of religiousness increases from adolescence to adulthood.

Time on Oct 17, 2004 referred to a book of Dean Hamer “The God Gene”

Chief of gene structure at the National Cancer Institute, Hamer not only claims that human spirituality is an adaptive trait, but he also says he has located one of the genes responsible, a gene that just happens to also code for production of the neurotransmitters that regulate our moods. Our most profound feelings of spirituality, according to a literal reading of Hamer’s work, may be due to little more than an occasional shot of intoxicating brain chemicals governed by our DNA. “I’m a believer that every thought we think and every feeling we feel is the result of activity in the brain,” Hamer says.

This looks very much like a completely physical view of spiritual affairs (Hamer became famous for his failure of the “gay gene” before abandoning science).

So we may better turn to the question if there is any theological background? I renember a famous guest lecture in Marburg 1980 about the Epistle to the Romans by Herbert Braun (Braun is a Bultmann scholar. Ernst Fuchs was in Marburg too; together with Ernst Käsemann and Günther Bornkamm they are all famous scholars of Rudolf Bultmann. Käsemann and Fuchs both wrote a “Commentary on Romans”).

Fuchs highlighted Rom 2:14 in King James translation saying:

13 For not the hearers of the law are just before God, but the doers of the law shall be justified.
14 For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves:
15 Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another;

Science and theology are not far away here. Maybe it is even common sense that most humans have an inherited deep feeling of religiousness.