Effects of high altitude exposure on components of blood and urine in mountaineers

Physiological correlations with impaired or umimpaired performance at high altitude were sought among 24 blood and urine parameters measured in 50 mountaineers and 21 observers before (preclimb) and after (postclimb) expeditions on Mt. McKinley. Values and per cent changes were compared for five degrees of impairment at high altitude. Average preclimb values were all near established normal levels and no correlations with subsequent involvement at high altitude were found. Postclimb samples contained more Hb, PCV, urea, LDH, and HBD and less bilirubin (P < 0.05). But no association was found between degrees of altitude impairment and preclimb/postclimb changes in any of the 24 blood and urine parameters. Additional results from samples collected at 4300 m showed "weaker" mountaineers excreted 1/4 as much Na in urine and had 50% more serum FFA concentration than stronger mountaineers.

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Zusammenfassung Bei 50 Bergsteigern und 21 Beobachtern wurden vor und nach einer Expedition zum Mt. McKinley (Alaska) für 24 Parameter im Blut und Harn die Beziehungen zur Abschwächung der Leistung in grosser Höhe untersucht. Zum Vergleich wurden 5 Grade von unbeeinflusster bis schwerer Schädigung in der Höhe verwendet. Die mittleren Werte vor dem Aufstieg lagen alle im Bereich der Normbreite. Beziehungen zu nachfolgenden Komplikationen in der Höhe bestanden nicht. Nach dem Aufstieg waren Hgb, Hämatokrit, Harnstoff, LDH, Hydroxybutyric Dehydrogenase erhöht und Bilirubin erniedrigt (P < 0, 05). Es liess sich jedoch für keinen Parameter eine Beziehung zwischen dem Ausmass der Höhenschädigung und den Veränderungen vor und nach dem Aufstieg nachweisen. Zusätzliche Ergebnisse von Proben, die in 4300 m Höhe gesammelt wurden, ergaben, dass schwache Bergsteiger ein Viertel soviel Na im Harn ausschieden und 50% mehr freie Fettsäuren im Blut aufwiesen als starke Bergsteiger.

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Resume On a mesuré 24 paramètre du sang et de l'urine de 50 alpinistes et 21 observateurs avant et après l'ascension du Mont McKinley (Canada). On a établi ensuite la corrélation physiologique existant entre ces paramètres et une diminution éventuelle des performances. Les valeurs absolues et le taux de modification ont été comparés à 5 degrés de diminution des capacités physiques à haute altitude. Les valeurs moyennes des analyses faites avant l'ascension ont toutes été voisines du niveau normal et on n'a pas constaté de corrélation avec les performances individuelles subséquentes. Les échantillons recueillis après l'ascension contenaient davantage de Hb, PCV, urée, LDH, et HBD, mais moins de bilirubine (P < 0, 05). On n'a cependant trouvé aucune relation entre le degré de diminution des performances et les modifications d'aucun des 24 paramètres retenus du sang ou de l'urine avant et après l'ascension. Des échantillons prélevés à 4300 m d'altitude ont montré que les alpinistes peu aguerris ne sécrétaient que le 1/4 du Na par l'urine, mais avaient 50% d'acides gras libres de plus dans le sang que les montagnards les plus résistants.

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Work supported by Themis Contract No DADA 17-68-C-8018     

Comparative effects of trichothecene mycotoxins on bovine platelet function: Acetyl T-2 toxin,a more potent inhibitor than T-2 toxin

The effects of the trichothecene mycotoxins (acetyl T-2 toxin, T-2 toxin, HT-2 toxin, palmityl T-2 toxin, diacetoxyscirpenol (DAS), deoxynivalenol (DON), and T-2 tetraol) on bovine platelet function were examined in homologous plasma stimulated with platelet activating factor (PAF). The mycotoxins inhibited platelet function with the following order of potency: acetyl T-2 toxin > palmityl T-2 toxin = DAS > HT-2 toxin = T-2 toxin. While T-2 tetraol was completely ineffective as an inhibitor, DON exhibited minimal inhibitory activity at concentrations above 10×10^?4M. The stability of the platelet aggregates formed was significantly reduced in all mycotoxin treated platelets compared to that of the untreated PAF controls. It is suggested that the increased sensitivity of PAF stimulated bovine platelets to the more lipophilic mycotoxins may be related to their more efficient partitioning into the platelet membrane compared to the more hydrophilic compounds.     

Active and passive cation transport and L antigen hertogeneity in low potassium sheep red cells

Several lines of experimental evidence are presented suggesting that the L antigens in low potassium (LK) sheep red cells are associated with separate Na(+)K(+) pump flux is distinct from the action of anti-L(l) on K(+) leak flux, implying that K(+) leak transport sites may not be converted into active pumps by the L antiserum. Treatment of LK red cells with trypsin completely abolished both the stimulation of K(+) pump flux and the enhancement of the rate of ouabain binding brought about by anti- L. That this effect is due to a total destruction of the L(p) determinant associated with the LK pump was evident from the complete failure of anti-L(p) to bind to trypsinized LK red cells. The L(p) antigen can be effectively protected against the trypsin attack by prior incubation with anti-L, indicating that the sites for antibody binding and trypsin action may be closely adjacent at the structural level. Trypsin treatment, however, did not interfere with anti-L(l) reducing ouabain insensitive K(+) leak influx, nor did it prevent binding of anti-L(ly), the hemolytically active L antibody which is probably identical with anti-L(l). The functional independence of the L(p) and L(l) sites was documented by the observation that anti-L(l) still reduced K(+) leak influx in LK cells with experimentally induced high potassium concentrations, at which K(+) pump flux is fully suppressed, whether or not anti-L(p) was binding to the L(p) antigen associated with the LK pump.     

Multiple effects of temperature,photoperiod and food quality on the performance of a pine sawfly

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