Heymans (Heymans), Corneille

March 28, 1892, Mr.. - July 18, 1968
Belgian pharmacologist Corneille Jean Francois Heymans was born in Ghent in the family of Jean and Marie Henriette (Henning), Heymans. His father was a professor of pharmacology and the rector of Ghent State University. Corneille received his secondary education in Turnhout and Ghent. His practicing medicine in the University of Ghent were interrupted by World War I, during which he served as a field artillery officer in the Belgian army. During the years of service he was awarded the Belgian Croix de Guerre, the Cross of Civil, Firefighters cross with 8 buckles, as well as the Military Cross in France.
After the cessation of hostilities in 1919. H. continued medical education and two years later received his medical degree at the University of Ghent. In 1922, Mr.. H. was appointed professor of pharmacology University of Ghent, but before the end of the decade was a graduate student in Paris, Lausanne (Switzerland), Vienna and London, as well as Western Reserve University (now Case-Western Reserve) in Cleveland.
. In the laboratory of the Institute of Pharmacology and Therapeutics behalf ZH.F
. Heymans (named after his father H.), he and his colleagues conducted sophisticated experiments on the pathophysiology of cardiovascular and respiratory systems, . in particular the influence of reflections of the first system in the frequency and rhythm of cardiac, . blood pressure and respiratory rate,
. Many of these experiments were carried out X. together with his father, who developed the experimental methods for isolation of nerve fibers and study the nerve reflexes involved in the regulation of respiratory and cardiovascular systems.
. For such experiments using two anesthetized dogs, one as a donor, the other - recipient
. Blood circulation of the recipient dog's head separated from blood circulation in the organs of the chest, abdomen and extremities. Blood to the head of the recipient dog cart with a plastic tube connecting the carotid artery of the donor dog and the dog of the recipient, and the blood from the head of the dog of the recipient is discharged through the jugular vein to the jugular veins of the donor dog. (Carotid arteries and jugular veins are located in the neck.) Nerve fibers between the head and torso of the recipient dog remained intact or were cut selectively, depending on the task.
Prior studies X. scientists thought, . that the cardiovascular and respiratory center in the medulla oblongata (lower section of the brain stem) regulate the speed of blood flow, . blood pressure and concentration of respiratory gases in blood and that these processes take place in accordance with the direct physiological needs of the organism and without the participation of reflexes of the nervous system,
. In the period from 1924 to 1927. H. and his colleagues have demonstrated that the rate of respiration is regulated by reflexes of the nervous system transmitted through the vagus and depressor nerves. Vagus nerve, referring to a pair of X cranial nerve, innervates the organs of the neck, chest, abdomen and is connected with the autonomic nervous system. Depressor nerve is formed by afferent fibers coming from the aortic arch baroreceptors.
. In one series of experiments, . When the researchers lowered the blood pressure in the dog recipient, . respiratory center in the medulla oblongata was excited, . which led to an increase in respiratory rate, with an increase in blood pressure, . aided by the injection of adrenalin, . contrary, . activity of the respiratory center and decreased respiratory rate decreased,
. And finally, with a significant increase in blood pressure occurred apnea, or sleep apnea. In another series of experiments X. cut all the nerves of the dog-recipient, with the exception of fibers emerging from reflexogenic area of the aorta - a specialized network of cells - nerve fibers and blood vessels located in the aortic wall near the exit of carotid arteries. The experimental results coincided, suggesting a contribution of nerve reflexes originating in the reflexogenic aortic area in the response of the respiratory system to changes in blood pressure.
In a new series of experiments X. studied the existence of nerve reflexes between the carotid sinus and vasomotor and respiratory centers in the medulla oblongata. Carotid sinus consists of a network of specialized cells, nerves and blood vessels in the wall of the carotid artery near the site of its division into internal and external branches. H. and his father found that in the carotid sinus receptors are sensitive to changes in blood pressure (or baroreceptors). Moreover, . with an increase in blood pressure increases the frequency of nerve impulses from the receptors of the carotid sinus to the vasomotor and respiratory centers in the medulla oblongata, . resulting in respiratory rate, . heart rate and blood pressure decrease,
. Conversely, when the pressure drop, the frequency of nerve impulses from the baroreceptors to the centers of the medulla is reduced, and respiration rate, heart rate and blood pressure increase.
. According to the pre-existing concepts, . chemical composition of the blood - oxygen, . carbon dioxide and hydrogen ion concentration, . or acid-alkaline balance, . - Directly affects the activity of neurons of the respiratory center in the medulla oblongata,
. In 1926, Mr.. H. and his colleagues showed that in the carotid sinus and aortic areas are chemical receptors (chemoreceptors) that are structurally similar to baroreceptors and are sensitive to certain stimuli. They then demonstrated that the concentrations of both respiratory gases and hydrogen ions are maintained in equilibrium reflexes of the nervous system, uniting vascular chemoreceptors, the respiratory center in the medulla oblongata and the lungs. They also noticed, . that a fall in the partial pressure of oxygen partial pressure of carbon dioxide increases, and that in the fall of the hydrogen ion concentration of vascular nerve impulses from the chemoreceptors to the medulla oblongata reflexly stimulate the respiratory rate and in the process change in the concentration of respiratory gases and acid-base balance is adjusted,
. When the reverse phenomenon occurs, the nerve impulses from the chemoreceptors to the medulla oblongata reflexively inhibit the respiration rate and corrects the deviation of respiratory gases and acid-base balance.
. Subsequent studies X
. showed that the partial pressure of oxygen - and not the content of oxygen in hemoglobin - is quite effective as a stimulus for vascular chemoreceptors. This observation explained why, when anemia and carbon monoxide poisoning respiratory rate unchanged. When anemia hemoglobin is abnormally low, with carbon monoxide poisoning, it displaces oxygen from hemoglobin, resulting in a reduction of oxyhemoglobin.
In 1925, Mr.. H. succeeded his father as rector of Ghent University and the Institute of Heymans. Author of numerous books and monographs, he spent Gerterovskie reading at New York University in 1934, and three years later - Danhemskie reading at Harvard.
Nobel Prize in Physiology or Medicine 1938. was awarded X. in 1939. 'for the discovery of the role of the sinus and aortic mechanisms in the regulation of respiration'. In a speech at the presentation Goran Liliestrand of the Karolinska Institute said that 'X. not only defined the role ... Some bodies ... He also greatly expanded our understanding of the regulation of respiration. He showed that the different methods used to stimulate breathing, are based on differing mechanisms'. In his Nobel lecture X. noted that 'changes in arterial pressure affect breathing, it was known earlier ... generally believed that this link ... carried out due to the direct effects of blood pressure or blood flow velocity in the brain to the respiratory center '. He stated that, 'however, we must reconsider and abandon the classical theory'. In conclusion, he summarized his research on the regulation of breathing.
In 1921, Mr.. H. married to Bertha Mason, a physician, they had two sons and two daughters. For many years, X. published and edited the magazine 'International Archives of pharmacodynamics and therapy' ( 'Archives Internationales de Pharmacodynamic et de Therapie'), which was founded by his father in 1895. He was passionately fond of literature, history of art and medicine.
X. died July 18, 1968, Mr.. in Knokke (Belgium).
Among the awards X. - Prize Alvarenga de Piauhi the Royal Academy of Medicine of Belgium (1931), . Prize Theophilus Glyuga Royal Academy of Sciences of Belgium (1931), . Prize in Medicine of the Belgian Government, . awarded every five years (1931), . Montiona Prize in Physiology Academy of France (1934), . Award of Pope Pius XI of the Pontifical Academy of Sciences (1938) and Prize Bourget, University of Bern,
. H. was an honorary member of the Royal Society of London, French Academy of Sciences, Medical Academy of Paris and New York Academy of Sciences.