Born 3rd October 1939 in Valparaíso, Chile. MD, Full Professor of Physiology, Faculty of Medicine, University of Chile, Honorary Member of Chilean Academy of Medicine
Drosselung der Nierendurehblutung fiihrt aufgrund der klassisehen Experimente yon HA~TW~C~-einem ... more Drosselung der Nierendurehblutung fiihrt aufgrund der klassisehen Experimente yon HA~TW~C~-einem ~Iitarbeitsr F. VoLm~n~s-, GOLDBLATT und PAo~ zu einer Erh6hung des systolischen und diasto]ischen Blutdrueks. Unter entspreehenden Bedingungen konnten CARPENTER, DAv~s u. AYahs (1961) sine Aktivierung des t{enin-Angiotensin-Systems und eine Steigerung der Aldosteronproduktion naehweisen, die vom AusmaB der Durehblutungsminderung abh/~ngig ist. Das Syndrom tIypertonie, gesteigerte l~enin-Angiotensin-Aktivit~t und Hyperaldosteronismus ist im Laufe der letzten Jahre aueh bei Patienten mit renaler Isch~mie beschrieben worden. Es handelte sieh in erster Linie um Kranke mit maligner Nephroangiosklerose, bei dsnen die Symptomatologie auf eine bilaterale renale Durehblutungsdrosselung bezogen wsrden kann, andererseits abet aueh um F~lle yon unilateraler Isch/~mie infolge Nierenarterienstenose, Nierenarterienaneurysma und schrumpfender Perinephritis (LAa~OlL UZICK, JA~vsz~w~cz, K~L~Y und LIEBE~ANN; LAI~AG~I, SEALEr und So~?~E~s; LAID-laW, Y~D~, B~a~) und GOdWiLL; tI£~z~, KLm~-SOH~I~T und ST~; Scgw~, SCltR6DER, SCHATTEN-F~OJX und Sc~I~Z; Se~6D~, DlSSMANN und DlSS-MANN; BAI~t~ACLOUGtI, BACCI:[US, gl~owlg, DAVIES, L~v~ und l~o~n~Tso~, Ubersicht bei WOLFF, U. a.). Die Minisehe Symptomatologie dsr F/~tle yon sog. renovaseul/~rem Hochdruek kann derjenigen des prim/iren Hyperaldosteronismus (M. Co~) auBerordentlieh/ihnlieh sein. Wghrend Hypertonie, tIypokali~mie mit metabolischer Alkalose und gesteigerte Aldosteron-aktivit~t sowohl beim prim~ren Hyperaldosteronismus als aueh bei Kranksn mit uni-und bilateraler Nierenisch/~mis vorkommen kann, ist die Aktivitgt des t{enin-AngiotensimSystems bei renovascul/irem Itoehdruek h/iufig erh6ht und beim prim/~ren Hyperaldosteronismus typischerweise erniedrigt (Co~-N, COHE~ und llovNE~). Dis Differentiald~agnose ist dadureh ersehwert, dab prim£rer Hyperaldosteronismus (M. Co~) und Nierenarterienstenose gleiehzeitig bestehen k6nnen (Ft~I~Z et al., BLOCH). Zur Beurteflung der Aldosteronaktivit/~t bei renovaseulgrem ]:[ochdruek sind am h~ufigsten die renale Exkretion und/oder die Aldosteronsekretionsrate zugrunde gelegt worden. Die genannten Parameter vermitteln abet nut einen Teitaspekt. Weitere Einblicke in den Stoffweehsel des Aldosterons sind yon einer umfassenden Analyse zu erwarten, die die gleiehzeitige Bestimmung yon renaler Exkretion, Sekretionsrate, metaboHseher Clearaneerate und Aldosteronplasmaspiegel einsehliegt. Ziel unserer Untersuchungen war es, eine derartige Analyse bei Kranken mit Nierenarterienstenose durehzuffihren. Von besonderem Interesse ersehien uns dabei, festzustellen, ob die ]4mderung der Aldosteronaktivit/~t bei dieser Nierenaffektion dnreh alleinige Ver/~nderung der Sekretion oder zusatzliche Modifikation des meta-* Mit Unters~iitzung der Deutsehen Forschtmgsgemeinschaft. bolisehen Abbaues bzw. der Exkretion des I-Iormons zust~nde kommt. Mit den vorgelegten Ergebnissen sell zugMch ein Beitrag zur Pathophysiologie des Renin-Angiotensin-Aldosteronsystems geleistet werden.
Background: Testicular aches have been reported to occur on exposure to high altitude (HA). As a ... more Background: Testicular aches have been reported to occur on exposure to high altitude (HA). As a painful expression of venous congestion at the pampiniform plexus, varicocele (VC) might be a consequence of cardiovascular adjustments at HA. Chile’s National Social Security Regulatory Body (SUSESO) emphasized evaluating this condition in the running follow-up study “Health effects of exposure to chronic intermittent hypoxia in Chilean mining workers.” Objectives: This study aimed at investigating the prevalence of VC in a population usually shifting between sea level and HA, thereby intermittently being exposed to hypobaric hypoxia. Methodology: Miners (n=492) agreed to be examined at their working place by a physician, in the context of a general health survey, for the presence of palpable VC, either visible or not. Among them was a group exposed to low altitude (LA) <2,400 m; n=123; another one exposed to moderate high altitude (MHA) working 3,050 m; n=70, and a third one exposed to very high altitude (VHA) >3,900 m, n=165. The Chi2 test and Kruskal-Wallis test were used for the descriptive analyses, and logistic regression was applied to evaluate the association of VC with exposure to HA. The Ethics Committee for Research in Human Beings, Faculty of Medicine, University of Chile, approved this project. Results: VC prevalence (grades 2 and 3) was found to be 10% at LA, 4.1% at MHA, and 16.7% at VHA (p≤0.05). Hemoglobin oxygen saturation (SaO2) was lower, and hemoglobin concentrations were higher in workers with high-grade VC at VHA compared to LA and MHA (Wilcoxon tests, p<0.001). Odds ratios (OR) for the association of VC with HA were 3.7 (95%CI: 1.26 to 12.3) and 4.06 (95%CI: 1.73 to 11.2) for MHA and VHA, respectively Conclusions: Association of VC with HA, a clinically relevant finding, may be related to blood volume centralization mediated by hypobaric hypoxia.
To study the effects of loxosceles laeta venom on red blood cells and the possible factors involv... more To study the effects of loxosceles laeta venom on red blood cells and the possible factors involved in hemolysis during arachnidism, in vitro models were designed to measure the role of loxosceles venom, calcium, complement and antibodies in the mechanism of red blood cell destruction. The degree of basal hemolysis was measured in a 5% suspension of group O, Rh (+) red blood cells in pH 7.4 buffer. In a similar suspension spider venom was added in amounts equivalent to one venom gland. After 72 hours of incubation, basal hemolysis was 5.59 +/- 2.04% which increased to 26.01 +/- 7.9% adding venom (p < 0.001). Adding calcium to the incubation medium, hemolysis increased to 88.5 +/- 7.16% (p < 0.001). Incubating red blood cells with control human serum and venom, hemolysis was 14.58 +/- 2.42%, which decreased significantly to 6.85 +/- 3.35% when serum was heat inactivated; this demonstrates an effect of the presence of complement. We did not find antivenom antibody production in patients with arachnidism 10, 15 or 30 days after the spider bite. It is thus demonstrated that loxosceles laeta venom has a direct lytic action on red blood cells that is calcium and complement dependent and is not mediated by antibodies or other substance.
Biochimica Et Biophysica Acta - Biomembranes, Mar 1, 1992
The diffusion-dependent formation or pyrenc excimers (excited dimers) was studied in normal and s... more The diffusion-dependent formation or pyrenc excimers (excited dimers) was studied in normal and spherocytic red ceil memlwane,. Pyrene emission was alternatively quenched in either bilayer half by Ion radiative enerw transfer to haemoglobin, i~rene excimer to monomer fluorescence intensity, ratio, !'/!, was 0.35 + 0.03 (S.E.) in washed red bleod cells obtained from normal donors (n =8) and 0.4$+0.03 (n = 13) in the correspoudlqg isolated, haemolgiolMn.free resealed membranes (P < 0.02). in the sl~ert~tic condition the respective values war 0.28 + 0.01 (n = 9) and 0.$3 d: 0.05 (n-9), P < 0.001. In c~ntrast to the decrease olr l'/I in red cells as compared to isolated membranes, being 22% in normal cells and 47% in spheroc~ic ones, haemol~hin added to the exofacial side ~r isolated membranes, mltectively, reduced i'll by I~ and 5%. In normal red cell membranes, p)~'enc appears to be hllher in the inner monolayer than in the miter one. In spheroc~ic membranes our remits indicate an enhanced transmembrane asymmetry in lipid monolayer fluidity, probably due to a defect or the membrmR protein skeleton organization.
Zusammenfassung Zum Nachweis möglicher Zusammenhänge der Reninaktivität im Plasma mit Veränderung... more Zusammenfassung Zum Nachweis möglicher Zusammenhänge der Reninaktivität im Plasma mit Veränderungen des Plasmavolumens und der Elektrolytausscheidung bei simulierter Hypervolämie durch Immersion wurden an 3 Versuchspersonen die Natrium-/Kaliumausscheidung, an 3 weiteren Versuchspersonen das Plasmavolumen und an 8 Probanden die Reninaktivität im Plasma nach einer einstündigen Liegeperiode und nach sechsstündiger Immersion gemessen.
Pflügers Archiv: European Journal of Physiology, 1969
A diuresis develops during immersion to the level of the neck in water of indifferent temperature... more A diuresis develops during immersion to the level of the neck in water of indifferent temperature [1,11]. This immersion diuresis is related to mechanical effects of the bath upon blood volume distribution. Hydro
American Journal of Physiology-cell Physiology, Dec 1, 1998
Celedó n, Gloria, Gustavo Gonzá lez, Carlos P. Sotomayor, and Claus Behn. Membrane lipid diffusio... more Celedó n, Gloria, Gustavo Gonzá lez, Carlos P. Sotomayor, and Claus Behn. Membrane lipid diffusion and band 3 protein changes in human erythrocytes due to acute hypobaric hypoxia.
Zusammenfassung Zur Untersuchung des renalen Phenolsulfonphthaleintransportes bei simulierter Hyp... more Zusammenfassung Zur Untersuchung des renalen Phenolsulfonphthaleintransportes bei simulierter Hypervolämie wurden an 6 Versuchspersonen simultan die PSP-Clearance (CPSP) und das Glomerulumfiltrat (CIn) während einer Kontrollperiode und während Immersion im thermoindifferenten Vollbad bestimmt. In einer späteren Versuchsreihe wurde der effektive Nierenplasmastrom (CPAH) gleichzeitig mit der glomerulären Filtrationsrate unter den gleichen Bedingungen gemessen, wobei an 4 Versuchspersonen während der Clearanceperioden außerdem noch die
International Journal of Molecular Sciences, Mar 22, 2020
Previous results evidenced acute exposure to high altitude (HA) weakening the relation between da... more Previous results evidenced acute exposure to high altitude (HA) weakening the relation between daily melatonin cycle and the respiratory quotient. This review deals with the threat extreme environments pose on body time order, particularly concerning energy metabolism. Working at HA, at poles, or in space challenge our ancestral inborn body timing system. This conflict may also mark many aspects of our current lifestyle, involving shift work, rapid time zone crossing, and even prolonged office work in closed buildings. Misalignments between external and internal rhythms, in the short term, traduce into risk of mental and physical performance shortfalls, mood changes, quarrels, drug and alcohol abuse, failure to accomplish with the mission and, finally, high rates of fatal accidents. Relations of melatonin with energy metabolism being altered under a condition of hypoxia focused our attention on interactions of the indoleamine with redox state, as well as, with autonomic regulations. Individual tolerance/susceptibility to such interactions may hint at adequately dealing with body timing disorders under extreme conditions.
INTRODUCTION A complete review of the above topic would be formidable indeed since it would compr... more INTRODUCTION A complete review of the above topic would be formidable indeed since it would comprise a good part of circulatory physiology, plus the physiology of salt and water balance and, last but not least, the physiology of fluid ex change through cell membranes (cell ...
Sexual (and gender)-dimorphism in tolerance to hypobaric hypoxia increasingly matters for a diffe... more Sexual (and gender)-dimorphism in tolerance to hypobaric hypoxia increasingly matters for a differential surveillance of human activities at high altitude (HA). At low altitudes, the prevalence of anxiety and depression in women has already been found to double when compared with men; it could be expected to even increase on exposure to HA. In purposefully caring for the health of women at HA, the present work explores the potential involvement of the tryptophan (Trp)-melatonin axis in mood changes on exposure to hypobaric hypoxia. The present work highlights some already known anxiogenic effects of HA exposure. Hypoxia and insomnia reduce serotonin (5-HT) availability; the latter defect being expressed as failure of brown adipose tissue (BAT) activation and mood disorders. Rapid eye movement (REM) sleep organization and synapsis restoration that are additionally affected by hypoxia impair memory consolidation. Affective complaints may thus surge, evolving into anxiety and depression. Sex-related differences in neural network organization and hormonal changes during the menstrual cycle, and certainly also during the life cycle, underscore the possibility of 5-HT-related mood alterations, particularly in women on HA exposure. The mean brain rate of 5-HT synthesis at sea level is already 1.5-fold higher in males than in females. sexual dimorphism also evidences the overexpression effects of SERT, a 5-HT transporter protein. Gonadal and thyroid hormones, as influenced by HA exposure, further modulate 5-HT availability and its effects in women. Besides caring for adequate oxygenation and maintenance of one's body core temperature, special precautions concerning women sojourning at HA should include close observations of hormonal cycles and, perhaps, also trials with targeted antidepressants.
Pflügers Archiv: European Journal of Physiology, 1973
Antibiotics which inhibit mammalian protein synthesis at different levels were administered intra... more Antibiotics which inhibit mammalian protein synthesis at different levels were administered intravenously to anesthetized, adrenergic a-receptor blocked rats. 60 sec after cycloheximide application (2.5, 5, 12.5 and 25 µg/100 g body wt), mean arterial pressure increased an average of 4, 19, 25 and 31% respectively. Mean arterial pressure returned to control values after time lapses varying between 5 and 30
Pflügers Archiv: European Journal of Physiology, 1977
Calcium was localized in the red cell membrane by light microscopy using chlorotetracycline hydro... more Calcium was localized in the red cell membrane by light microscopy using chlorotetracycline hydrochloride (CTC) as chelate probe. Treating human erythrocytes with CTC dissolved in saline free of divalent cations, leads to a 530 nm fluorescence emission in the cell border and to characteristic cell shape changes which were evaluated to assess intramembrane calcium distribution. CTC prevented and reverted erythrocyte crenation induced either by washing or superfusing the cells with saline. The ionophore A23187, EGTA and glucose depletion depressed the shape modifying effect of CTC. Thus, CTC appears to act on red cell shape by complex formation with membrane associated calcium. This is further confirmed by the failure of degraded CTC, devoid of metal binding capacity, to modify the crenated shape. The CTC effect can be reverted bN superfusing the erythrocytes with CTC-free medium. Thus, calcium binds more tightly to the membrane than to CTC and is not displaced by the antibiotic. If the bilayer couple hypothesis [Sheetz, M. P., Singer, S. J., Proc. Natl. Acad. Sci. USA 71, 4457-4461 (1974)] applies, crenation is reverted by expansion of the inner membrane half relative to the outer membrane half. Expansion of the inner membrane half results from intercalation of CTC which binds to calcium. Thus, calcium in the red cell membrane preferentially occupies the inner leaflet of the bilayer.
Advances in Experimental Medicine and Biology, 1994
Tissue oxygen tension can be elevated under controlled conditions by simultaneously increasing th... more Tissue oxygen tension can be elevated under controlled conditions by simultaneously increasing the O2 concentration of inspired air and the ambient pressure (Jamieson and Van Den Brank,1963). Increasing tissue oxygen tension by hyperbaric oxygenation (HBO) reduces organ blood flow (Muhvich et al.,1992; Bergo and Tyssebotn,1992) as well as some forms of edema (Nylander et al.,1985; Yamaguchi et al.,1990; Gehrs et al.,1991). An acutely reversible decrease of blood hemoglobin concentration by HBO (Bergo and Tyssebotn, 1992) further suggests hyperoxia affecting body fluid distribution.
Drosselung der Nierendurehblutung fiihrt aufgrund der klassisehen Experimente yon HA~TW~C~-einem ... more Drosselung der Nierendurehblutung fiihrt aufgrund der klassisehen Experimente yon HA~TW~C~-einem ~Iitarbeitsr F. VoLm~n~s-, GOLDBLATT und PAo~ zu einer Erh6hung des systolischen und diasto]ischen Blutdrueks. Unter entspreehenden Bedingungen konnten CARPENTER, DAv~s u. AYahs (1961) sine Aktivierung des t{enin-Angiotensin-Systems und eine Steigerung der Aldosteronproduktion naehweisen, die vom AusmaB der Durehblutungsminderung abh/~ngig ist. Das Syndrom tIypertonie, gesteigerte l~enin-Angiotensin-Aktivit~t und Hyperaldosteronismus ist im Laufe der letzten Jahre aueh bei Patienten mit renaler Isch~mie beschrieben worden. Es handelte sieh in erster Linie um Kranke mit maligner Nephroangiosklerose, bei dsnen die Symptomatologie auf eine bilaterale renale Durehblutungsdrosselung bezogen wsrden kann, andererseits abet aueh um F~lle yon unilateraler Isch/~mie infolge Nierenarterienstenose, Nierenarterienaneurysma und schrumpfender Perinephritis (LAa~OlL UZICK, JA~vsz~w~cz, K~L~Y und LIEBE~ANN; LAI~AG~I, SEALEr und So~?~E~s; LAID-laW, Y~D~, B~a~) und GOdWiLL; tI£~z~, KLm~-SOH~I~T und ST~; Scgw~, SCltR6DER, SCHATTEN-F~OJX und Sc~I~Z; Se~6D~, DlSSMANN und DlSS-MANN; BAI~t~ACLOUGtI, BACCI:[US, gl~owlg, DAVIES, L~v~ und l~o~n~Tso~, Ubersicht bei WOLFF, U. a.). Die Minisehe Symptomatologie dsr F/~tle yon sog. renovaseul/~rem Hochdruek kann derjenigen des prim/iren Hyperaldosteronismus (M. Co~) auBerordentlieh/ihnlieh sein. Wghrend Hypertonie, tIypokali~mie mit metabolischer Alkalose und gesteigerte Aldosteron-aktivit~t sowohl beim prim~ren Hyperaldosteronismus als aueh bei Kranksn mit uni-und bilateraler Nierenisch/~mis vorkommen kann, ist die Aktivitgt des t{enin-AngiotensimSystems bei renovascul/irem Itoehdruek h/iufig erh6ht und beim prim/~ren Hyperaldosteronismus typischerweise erniedrigt (Co~-N, COHE~ und llovNE~). Dis Differentiald~agnose ist dadureh ersehwert, dab prim£rer Hyperaldosteronismus (M. Co~) und Nierenarterienstenose gleiehzeitig bestehen k6nnen (Ft~I~Z et al., BLOCH). Zur Beurteflung der Aldosteronaktivit/~t bei renovaseulgrem ]:[ochdruek sind am h~ufigsten die renale Exkretion und/oder die Aldosteronsekretionsrate zugrunde gelegt worden. Die genannten Parameter vermitteln abet nut einen Teitaspekt. Weitere Einblicke in den Stoffweehsel des Aldosterons sind yon einer umfassenden Analyse zu erwarten, die die gleiehzeitige Bestimmung yon renaler Exkretion, Sekretionsrate, metaboHseher Clearaneerate und Aldosteronplasmaspiegel einsehliegt. Ziel unserer Untersuchungen war es, eine derartige Analyse bei Kranken mit Nierenarterienstenose durehzuffihren. Von besonderem Interesse ersehien uns dabei, festzustellen, ob die ]4mderung der Aldosteronaktivit/~t bei dieser Nierenaffektion dnreh alleinige Ver/~nderung der Sekretion oder zusatzliche Modifikation des meta-* Mit Unters~iitzung der Deutsehen Forschtmgsgemeinschaft. bolisehen Abbaues bzw. der Exkretion des I-Iormons zust~nde kommt. Mit den vorgelegten Ergebnissen sell zugMch ein Beitrag zur Pathophysiologie des Renin-Angiotensin-Aldosteronsystems geleistet werden.
Background: Testicular aches have been reported to occur on exposure to high altitude (HA). As a ... more Background: Testicular aches have been reported to occur on exposure to high altitude (HA). As a painful expression of venous congestion at the pampiniform plexus, varicocele (VC) might be a consequence of cardiovascular adjustments at HA. Chile’s National Social Security Regulatory Body (SUSESO) emphasized evaluating this condition in the running follow-up study “Health effects of exposure to chronic intermittent hypoxia in Chilean mining workers.” Objectives: This study aimed at investigating the prevalence of VC in a population usually shifting between sea level and HA, thereby intermittently being exposed to hypobaric hypoxia. Methodology: Miners (n=492) agreed to be examined at their working place by a physician, in the context of a general health survey, for the presence of palpable VC, either visible or not. Among them was a group exposed to low altitude (LA) &lt;2,400 m; n=123; another one exposed to moderate high altitude (MHA) working 3,050 m; n=70, and a third one exposed to very high altitude (VHA) &gt;3,900 m, n=165. The Chi2 test and Kruskal-Wallis test were used for the descriptive analyses, and logistic regression was applied to evaluate the association of VC with exposure to HA. The Ethics Committee for Research in Human Beings, Faculty of Medicine, University of Chile, approved this project. Results: VC prevalence (grades 2 and 3) was found to be 10% at LA, 4.1% at MHA, and 16.7% at VHA (p≤0.05). Hemoglobin oxygen saturation (SaO2) was lower, and hemoglobin concentrations were higher in workers with high-grade VC at VHA compared to LA and MHA (Wilcoxon tests, p&lt;0.001). Odds ratios (OR) for the association of VC with HA were 3.7 (95%CI: 1.26 to 12.3) and 4.06 (95%CI: 1.73 to 11.2) for MHA and VHA, respectively Conclusions: Association of VC with HA, a clinically relevant finding, may be related to blood volume centralization mediated by hypobaric hypoxia.
To study the effects of loxosceles laeta venom on red blood cells and the possible factors involv... more To study the effects of loxosceles laeta venom on red blood cells and the possible factors involved in hemolysis during arachnidism, in vitro models were designed to measure the role of loxosceles venom, calcium, complement and antibodies in the mechanism of red blood cell destruction. The degree of basal hemolysis was measured in a 5% suspension of group O, Rh (+) red blood cells in pH 7.4 buffer. In a similar suspension spider venom was added in amounts equivalent to one venom gland. After 72 hours of incubation, basal hemolysis was 5.59 +/- 2.04% which increased to 26.01 +/- 7.9% adding venom (p < 0.001). Adding calcium to the incubation medium, hemolysis increased to 88.5 +/- 7.16% (p < 0.001). Incubating red blood cells with control human serum and venom, hemolysis was 14.58 +/- 2.42%, which decreased significantly to 6.85 +/- 3.35% when serum was heat inactivated; this demonstrates an effect of the presence of complement. We did not find antivenom antibody production in patients with arachnidism 10, 15 or 30 days after the spider bite. It is thus demonstrated that loxosceles laeta venom has a direct lytic action on red blood cells that is calcium and complement dependent and is not mediated by antibodies or other substance.
Biochimica Et Biophysica Acta - Biomembranes, Mar 1, 1992
The diffusion-dependent formation or pyrenc excimers (excited dimers) was studied in normal and s... more The diffusion-dependent formation or pyrenc excimers (excited dimers) was studied in normal and spherocytic red ceil memlwane,. Pyrene emission was alternatively quenched in either bilayer half by Ion radiative enerw transfer to haemoglobin, i~rene excimer to monomer fluorescence intensity, ratio, !'/!, was 0.35 + 0.03 (S.E.) in washed red bleod cells obtained from normal donors (n =8) and 0.4$+0.03 (n = 13) in the correspoudlqg isolated, haemolgiolMn.free resealed membranes (P < 0.02). in the sl~ert~tic condition the respective values war 0.28 + 0.01 (n = 9) and 0.$3 d: 0.05 (n-9), P < 0.001. In c~ntrast to the decrease olr l'/I in red cells as compared to isolated membranes, being 22% in normal cells and 47% in spheroc~ic ones, haemol~hin added to the exofacial side ~r isolated membranes, mltectively, reduced i'll by I~ and 5%. In normal red cell membranes, p)~'enc appears to be hllher in the inner monolayer than in the miter one. In spheroc~ic membranes our remits indicate an enhanced transmembrane asymmetry in lipid monolayer fluidity, probably due to a defect or the membrmR protein skeleton organization.
Zusammenfassung Zum Nachweis möglicher Zusammenhänge der Reninaktivität im Plasma mit Veränderung... more Zusammenfassung Zum Nachweis möglicher Zusammenhänge der Reninaktivität im Plasma mit Veränderungen des Plasmavolumens und der Elektrolytausscheidung bei simulierter Hypervolämie durch Immersion wurden an 3 Versuchspersonen die Natrium-/Kaliumausscheidung, an 3 weiteren Versuchspersonen das Plasmavolumen und an 8 Probanden die Reninaktivität im Plasma nach einer einstündigen Liegeperiode und nach sechsstündiger Immersion gemessen.
Pflügers Archiv: European Journal of Physiology, 1969
A diuresis develops during immersion to the level of the neck in water of indifferent temperature... more A diuresis develops during immersion to the level of the neck in water of indifferent temperature [1,11]. This immersion diuresis is related to mechanical effects of the bath upon blood volume distribution. Hydro
American Journal of Physiology-cell Physiology, Dec 1, 1998
Celedó n, Gloria, Gustavo Gonzá lez, Carlos P. Sotomayor, and Claus Behn. Membrane lipid diffusio... more Celedó n, Gloria, Gustavo Gonzá lez, Carlos P. Sotomayor, and Claus Behn. Membrane lipid diffusion and band 3 protein changes in human erythrocytes due to acute hypobaric hypoxia.
Zusammenfassung Zur Untersuchung des renalen Phenolsulfonphthaleintransportes bei simulierter Hyp... more Zusammenfassung Zur Untersuchung des renalen Phenolsulfonphthaleintransportes bei simulierter Hypervolämie wurden an 6 Versuchspersonen simultan die PSP-Clearance (CPSP) und das Glomerulumfiltrat (CIn) während einer Kontrollperiode und während Immersion im thermoindifferenten Vollbad bestimmt. In einer späteren Versuchsreihe wurde der effektive Nierenplasmastrom (CPAH) gleichzeitig mit der glomerulären Filtrationsrate unter den gleichen Bedingungen gemessen, wobei an 4 Versuchspersonen während der Clearanceperioden außerdem noch die
International Journal of Molecular Sciences, Mar 22, 2020
Previous results evidenced acute exposure to high altitude (HA) weakening the relation between da... more Previous results evidenced acute exposure to high altitude (HA) weakening the relation between daily melatonin cycle and the respiratory quotient. This review deals with the threat extreme environments pose on body time order, particularly concerning energy metabolism. Working at HA, at poles, or in space challenge our ancestral inborn body timing system. This conflict may also mark many aspects of our current lifestyle, involving shift work, rapid time zone crossing, and even prolonged office work in closed buildings. Misalignments between external and internal rhythms, in the short term, traduce into risk of mental and physical performance shortfalls, mood changes, quarrels, drug and alcohol abuse, failure to accomplish with the mission and, finally, high rates of fatal accidents. Relations of melatonin with energy metabolism being altered under a condition of hypoxia focused our attention on interactions of the indoleamine with redox state, as well as, with autonomic regulations. Individual tolerance/susceptibility to such interactions may hint at adequately dealing with body timing disorders under extreme conditions.
INTRODUCTION A complete review of the above topic would be formidable indeed since it would compr... more INTRODUCTION A complete review of the above topic would be formidable indeed since it would comprise a good part of circulatory physiology, plus the physiology of salt and water balance and, last but not least, the physiology of fluid ex change through cell membranes (cell ...
Sexual (and gender)-dimorphism in tolerance to hypobaric hypoxia increasingly matters for a diffe... more Sexual (and gender)-dimorphism in tolerance to hypobaric hypoxia increasingly matters for a differential surveillance of human activities at high altitude (HA). At low altitudes, the prevalence of anxiety and depression in women has already been found to double when compared with men; it could be expected to even increase on exposure to HA. In purposefully caring for the health of women at HA, the present work explores the potential involvement of the tryptophan (Trp)-melatonin axis in mood changes on exposure to hypobaric hypoxia. The present work highlights some already known anxiogenic effects of HA exposure. Hypoxia and insomnia reduce serotonin (5-HT) availability; the latter defect being expressed as failure of brown adipose tissue (BAT) activation and mood disorders. Rapid eye movement (REM) sleep organization and synapsis restoration that are additionally affected by hypoxia impair memory consolidation. Affective complaints may thus surge, evolving into anxiety and depression. Sex-related differences in neural network organization and hormonal changes during the menstrual cycle, and certainly also during the life cycle, underscore the possibility of 5-HT-related mood alterations, particularly in women on HA exposure. The mean brain rate of 5-HT synthesis at sea level is already 1.5-fold higher in males than in females. sexual dimorphism also evidences the overexpression effects of SERT, a 5-HT transporter protein. Gonadal and thyroid hormones, as influenced by HA exposure, further modulate 5-HT availability and its effects in women. Besides caring for adequate oxygenation and maintenance of one's body core temperature, special precautions concerning women sojourning at HA should include close observations of hormonal cycles and, perhaps, also trials with targeted antidepressants.
Pflügers Archiv: European Journal of Physiology, 1973
Antibiotics which inhibit mammalian protein synthesis at different levels were administered intra... more Antibiotics which inhibit mammalian protein synthesis at different levels were administered intravenously to anesthetized, adrenergic a-receptor blocked rats. 60 sec after cycloheximide application (2.5, 5, 12.5 and 25 µg/100 g body wt), mean arterial pressure increased an average of 4, 19, 25 and 31% respectively. Mean arterial pressure returned to control values after time lapses varying between 5 and 30
Pflügers Archiv: European Journal of Physiology, 1977
Calcium was localized in the red cell membrane by light microscopy using chlorotetracycline hydro... more Calcium was localized in the red cell membrane by light microscopy using chlorotetracycline hydrochloride (CTC) as chelate probe. Treating human erythrocytes with CTC dissolved in saline free of divalent cations, leads to a 530 nm fluorescence emission in the cell border and to characteristic cell shape changes which were evaluated to assess intramembrane calcium distribution. CTC prevented and reverted erythrocyte crenation induced either by washing or superfusing the cells with saline. The ionophore A23187, EGTA and glucose depletion depressed the shape modifying effect of CTC. Thus, CTC appears to act on red cell shape by complex formation with membrane associated calcium. This is further confirmed by the failure of degraded CTC, devoid of metal binding capacity, to modify the crenated shape. The CTC effect can be reverted bN superfusing the erythrocytes with CTC-free medium. Thus, calcium binds more tightly to the membrane than to CTC and is not displaced by the antibiotic. If the bilayer couple hypothesis [Sheetz, M. P., Singer, S. J., Proc. Natl. Acad. Sci. USA 71, 4457-4461 (1974)] applies, crenation is reverted by expansion of the inner membrane half relative to the outer membrane half. Expansion of the inner membrane half results from intercalation of CTC which binds to calcium. Thus, calcium in the red cell membrane preferentially occupies the inner leaflet of the bilayer.
Advances in Experimental Medicine and Biology, 1994
Tissue oxygen tension can be elevated under controlled conditions by simultaneously increasing th... more Tissue oxygen tension can be elevated under controlled conditions by simultaneously increasing the O2 concentration of inspired air and the ambient pressure (Jamieson and Van Den Brank,1963). Increasing tissue oxygen tension by hyperbaric oxygenation (HBO) reduces organ blood flow (Muhvich et al.,1992; Bergo and Tyssebotn,1992) as well as some forms of edema (Nylander et al.,1985; Yamaguchi et al.,1990; Gehrs et al.,1991). An acutely reversible decrease of blood hemoglobin concentration by HBO (Bergo and Tyssebotn, 1992) further suggests hyperoxia affecting body fluid distribution.
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