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X J Musacchia

Publications and source records attributed to X J Musacchia.

At least 73 records · Page 4Linked to original sources
PubMed1975

Mechanisms of radio-protection by catecholamines in the hamster (Mesocricetus auratus).

Whole-body exposure to 1000 or 2000 rads in a 60Co source was used to study radio-protection by norepinephrine, isoproterenol, and phenylephrine in normal and splenectomized hamsters. After exposure, the animals were caged individually, and percent survivals were recorded daily. The aortic blood pressure of permanently cannulated, unanaesthetized hamsters was measured to test the vasoconstriction-hypoxia mechanism of radio-protection, and plasma calcium levels were measured to test the hypothesis that isoproterenol protects through a mechanism of hypercalcaemia-stimualted cell proliferation. The data support the vasoconstriction-hypoxia mechanism for agents stimulating the alpha receptors, while beta agonists seem to protect through a hypotensive-hypoxia mechanism similar to that of histamine. All the catecholamines protect against the haematopoietic syndrome, but show no evidence of protection against the gastrointestinal syndrome.

Animals↗
PubMed1975

Renal function in the hibernating, and hypothermic hamster Mesocricetus auratus.

Plasma and urine concentrations of Na+, K+, and urea were examined in hibernating, hypothermic, and normothermic hamsters. Plasma Na+ and K+ appear unaffected by 48 h of hypothermia (T-re 7 degrees C); however, plasma Na+ increased (P smaller than 0.05) from control values of 125.8 plus or minus 10.2 to 173 plus or minus 9.2 meg/liter in hibernators. Plasma K+ of the hibernator increased to 9.6 plus or minus 3.2 meq/liter from control values of 5.5 plus or minus 0.8 meq/liter (P smaller than 0.05). Plasma urea concentrations were increased (P smaller than 0.05) in both metabolically depressed groups from a control value of 0.5 plus or minus .05 to 0.8 plus or minus .16 and 7.2 plus or minus 2.8 mM in hypothermic and hibernating groups, respectively. Urine concentrations of solute for the hypothermic animals showed no detactable change from control values for Na+ and a decrease for both K+ and urea. Concentrations from hibernators showed a decrease from control values for both Na+ and K+ with no detectable change in urea. Renal tissue slice analysis demonstrated a marked corticomedullary solute gradient for Na+ and urea in normothermic control animals which is eliminated in hamsters hypothermic for 48 h and reduced in animals hypothermic for 15 min. Rewarming animals did not show a return of the solute gradient at T-re 18 degrees C. However, animals that had rewarmed to T-re 37 degrees C demonstrated a complete return with no difference (P greater than 0.05) from control values. Hibernators showed a slight (P smaller than 0.05) gradient for Na+ and no gradient for urea. Animals in all instances demonstrated a decrease in K+ concentration from cortex to papilla. A greater concentration of K+ was found in the renal cortex of animals hypothermic for 15 min and in hibernators (P smaller than 0.05).

Animals↗
PubMed1975

Erythrocyte 2,3-diphosphoglycerate concentrations in hibernating, hypothermic, and rewarming hamsters (38589).

Hematocrit, hemoglobin and erythrocyte 2,3-DPG concentrations were examined in normothermic control, hibernating, and helium-cold hypothermic hamsters. Hematocrit was not signigicantly different (P greater than 0.05) between groups, but did reflect alterations reported for hemoglobin. Hemoglobin concentration did not change from control values during 12 hr at Tre 7 degrees; however, approximately a 20% decrease occurred in hibernators (48 hrs) and animals hypothermic (24 hr). 2,3-DPG concentrations declined 39.1 and 33.9% from control values in the hibernating and 24 hr hypothermic groups, respectively. No change was observed in animals hypothermic for 12 hr. Both parameters were studied in the aroused animal. Hemoglobin returns to control values immediately after the animals reached a stable Tre approximately equal to 37 degrees. Although 2,3-DPG levels increased during arousal, they were still 10% lower than control values in both metabolically depressed groups. 2,3-DPG remained approximately 10% less than controls in rewarmed hypothermic animals studied 2 hr after reaching stable Tre approximately equal to 37 degrees. The data are discussed in terms of cold depression of erythrocyte glycolysis.

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