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At least 19 recordsLinked to original sources
PubMed1978

"La Pression barométrique": Paul Bert's hypoxia theory and its critics.

Just one hundred years ago, Paul Bert published his most famous book, La Pression Barométrique..., summarizing his work on the physiological effects of altering barometric pressure. After a summary of Bert's life and contributions, this paper focuses on his experimental demonstration of the hypoxic etiology of altitude sickness. Bert showed that functional impairment or death occurred in each of a variety of species at a certain inspired oxygen pressure regardless of what combination of barometric pressure and oxygen percentage was used to achieve it. He further showed that the oxygen pressures impairing function were those producing arterial hypoxemia, and that raising the inspired oxygen percentage protected against the effects of altitudes that would otherwise endanger life. For the next several decades some other physiologists were unable to confirm these points. The criticisms of Setschenow, of Cyon, of Fraenkel and Geppert, of Mosso, and of Kronecker are analyzed in the light of modern knowledge.

Altitude Sickness↗
PubMed1992

The effects of barometric pressure according to Paul Bert: the question today.

The scientific activity of Paul Bert was very diverse, but his main achievements concern the effects of barometric pressure upon life. The fundamental physiological effect of decreasing barometric pressure is due to the concomitant fall of the O2 partial pressure. The effects of lowering or raising the barometric pressure can be countered by increasing or decreasing the O2 fraction in the air. Extreme hyperoxia modifies cellular metabolism of all living beings: this is O2 poisoning, the Paul Bert effect. Rapid decompressions from several atmospheres, or even from sea level to high altitude, can entail the formation of bubbles of N2 dissolved under the high pressure in the tissues and blood. Decompression accidents may be prevented by decompressing slowly. Immediate recompression is the only way to overcome decompression accidents, as the N2 is forced back into solution. These main discoveries were not universally accepted before about 1915. However, since Paul Bert's time, some additional effects of changes of the barometric pressure, for example related to the variation of gas diffusivity and density, have been pointed out. It is also clear that some factors other than low barometric pressure, for instance radiation, temperature, humidity etc. may play important roles in the mechanism of mountain sickness. However, it remains that the main factor is hypoxia, since oxygen inhalation or recompression lead to a quick recovery.

Atmospheric Pressure↗
PubMed1989

Chronic administration of aqueous extract of Stevia rebaudiana (Bert.) Bertoni in rats: endocrine effects.

1. The effects of the active principles of S. rebaudiana (SR) on endocrine parameters of male rats were studied upon chronic administrations (60 days) of a concentrated, crude extract of its leaves, starting at prepubertal age (25-30 days old). 2. The following determinations were made: glycemia; serum levels of T3 and T4; available binding sites in thyroid hormone-binding proteins (T3R index); binding of [3H]R 1881 to prostate cytosol; zinc content in prostate, testis, submandibular salivary gland (SMG) and pancreas; water content in testis and prostate. The body weight gain and the final weight of testis, prostate, seminal vesicle, SMG and adrenal were also studied. 3. Results showed that the SR-treated group did not significantly differ from the control group, with exception to the seminal vesicle weight, which fell by about 60%. 4. It is concluded that if the SR extract does have some potential to decrease rat fertility at all, this effect is almost certainly not exerted on the male.

Animals↗
PubMed1975

[Common categories in the speech of Bert Brechts and the speech of a schizophrenic].

The author demonstrates structural similarities and phenomenal resemblances between the language of Bertolt Brecht and the idiosyncrasies of expression of schizophrenic subjects. He compares some typical modes of expression on the basis of which he draws some general conclusions. What they have in common appears to be a 'disorganization' of the world as we know it which consists of 'things' and 'symbols'. It is only the notion of the more or less conscious use of these means of expression which allows one to distinguish between the 'linguistic world' of Brecht and that of schizophrenic subjects. These findings agree with those of other studies which have revealed affinities between the artistic expression of the mentally deranged and certain trends in art. The author has elaborated a number of heuristic categories which may be employed to understand the various modes of expression and has presented them in table form.

Humans↗
PubMed1992

[Ervin Neher and Bert Sakmann, 1991 Nobel Prize laureates for physiology and medicine. Ion channels and the patch clamp technic].

E. Neher and B. Sakmann were awarded the Nobel Prize for achievements in Physiology or Medicine in 1991. They developed the "patch clamp technique" which enables measurement of ionic currents through channels in the plasma membrane of living cells, and characterized their functional properties. An overview of three types of ion channels is presented: voltage gated channels, ligand gated channels and G-protein gated channels. An attempt was made to correlate their function with the structure of the protein complexes that represent ionic channels. The perforated patch clamp technique is mentioned as an alternative that enables recording of membrane currents without washing out the content of the interior of the cells.

Animals↗