Red cell and core temperature in spelunking.

Alpine spelunking is practiced in darkness, isolation, cold and high humidity. In this paper we study the acute haematological effects of prolonged strenuous activity in five spelunkers who spent about 20 hours in a 700-meter deep cave without resting much or sleeping. On four occasions, we measured their red cell counts, haemoglobin, mean corpuscular volume and percentage changes of plasma volume. We also measured their rectal temperature to estimate, in the limits of this parameter, thermoregulatory response. After the spelunkers descended 5 hours to the bottom of the cave, we detected, in all of them, a significant increase in red cell counts and haemoglobin and a drop in mean corpuscular volume and plasma volume. The day after recovery, we found a significant drop in all red cell parameters and a rise in plasma volumes. Rectal temperatures peaked at the exit. These findings suggest that alpine spelunking induces an initial haemoconcentration (bottom of the cave) followed by a haemodilution (the day after recovery). Sport anaemia was not detected. The rise of rectal temperature suggests that spelunking is a very strenuous sport with possible transpiration problems.

Muscular damage and intravascular haemolysis during an 18 hour subterranean exploration in a cave of 700 m depth.

OBJECTIVE: To verify presence and severity of muscular and/or intravascular damage during a subterranean exploration of long duration. METHODS: We measured serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH) as markers of muscular damage. We also measured haptoglobin as a marker of intravascular haemolysis, and platelets and leucocytes as markers of inflammation. RESULTS: We found in all the participants an increase in CK, LDH, and platelets and leucocytes (mainly due to neutrophilia and monocytosis), and a decrease in the level of haptoglobin and circulating lymphocytes. CONCLUSIONS: The observed data suggest that continuous effort during long alpine subterranean explorations, environmental conditions, sleep deprivation, multiple impacts on rocks, and compression caused by bindings of the caving harness cause muscle damage, intravascular haemolysis, inflammation response, and immunological changes.

Experimental urethane anaesthesia prevents digoxin intoxication: electrocardiographic and histological study in rabbit.

An electrocardiographic and histological study was performed in rabbit to detect the effects of urethane (ethyl carbamate) intraperitoneal (i.p.) anaesthesia in digoxin intoxication, since it has been previously shown that this anaesthetic and digitalis glycosides exert specific peripheral effects on the cardiovascular system involving central structures of the autonomic nervous system. We observed that i.p. urethane anaesthesia prevented the onset of the electrocardiographic signs of digitalis intoxication, as well as inhibiting the appearance of histological myocardial alterations after treatment with toxic digoxin doses. On the other hand, lethal arrhythmias and severe myocardial damage were observed in animals that had not undergone preliminary urethane anaesthesia. These results indicate that the effect exerted by urethane in preventing the toxic action of digoxin is probably due to a decrease of sympathetic activity in anaesthetized animals by centrally mediated sympathetic inhibition.

The influence of dental metal alloys on cell proliferation and fibronectin arrangement in human fibroblast cultures.

The biocompatibility of six single-phase dental metal alloys was studied by determining cell proliferation rates correlated to the arrangement of fibronectin (FN) in fibroblast cultures. Immunocytochemical methods were used to detect cell proliferation by 5-bromodeoxyuridine (BrdU) incorporation, and FN organization [i.e. diffuse in the extracellular matrix and organized in fibrils or in focal adhesions (FA)] in human fibroblast cultures. Cell proliferation rates were related to FN arrangement and in particular a higher percentage of cells in the S-phase was related to a predominance of FA. The greatest difference in behaviour compared to that of the controls was detected after 120 and 168 hr: at these times, as well as at previous ones, the alloy with the highest Au content seemed the most biocompatible among those tested, as it behaved in a very similar way to the controls. In contrast, fibroblasts exposed to the other five alloys showed different behaviours from the controls. It is assumed that a correlation exists between FN organization and the percentage of BrdU-positive cells, and that these features vary in the presence of different alloys. The observation of FN arrangement together with cell proliferation rates could be another useful tool in determining the biocompatibility of dental metal alloys.

Role of the parasympathetic autonomic nervous system in digitalis intoxication: electrocardiographic and histological study.

The role of the parasympathetic autonomic nervous system (ANS) in digoxin intoxication was investigated in atropine pretreated conscious rabbits. Both the electrocardiographic registration and the histologic analysis indicated possible prevention of lethal arrhythmias by atropine pretreatment. The hearts of animals pretreated with atropine appeared less damaged, since they presented only a light cytoplasmic vacuolization. It was evident that the administration of digoxin without atropine pretreatment provoked dramatic signs of digitalis intoxication followed by animal death. Myocardia of these rabbits were highly damaged. On the other hand, our experimental data indicated that the abolishment of the vagal tone by atropine blockade caused only signs (i.e. inversion of the T wave) due to myocardial ischemia, to which the light cytoplasmic vacuolation could be correlated. Myocardial ischemia could be caused by constriction of coronary blood vessels, which could be consequential to both the prevalent activity of the orthosympathetic ANS, following parasympathetic blockade, and direct digoxin effects on vascular fibrecells, which both produce vasoconstriction. Therefore, it is reasonable to assume that the parasympathetic ANS plays a major role in digitalis intoxication in rabbits.

Autopsical observations on the blood vessels in the human lower limb.

The heterolateral femoral triangles (Scarpa's triangles, trigona femoralis) have been examined in 48 dead adult subjects of Trieste to detect relevant macroanatomical variations, performing the autopsical method. Interesting differences have been found in the topography of blood vessels, above all the arteries, from that described as normal, or better, more frequent, in the literature. The three most relevant anatomical variations for both arteries and veins are described in detail; summarizing tables and related graphics are presented for the globality of the examined cases. The percentage ratio of the observed topographic variations appears to be remarkably different when compared to their European frequency and this may be due to the exiguous number of te cases (48 subjects, that is, 96 femoral triangles) examined by us; however, the three most relevant findings have not been reported in the literature yet. Therefore, it is also reasonable to assume that the variations described in this study, either for their peculiarity or their relevant frequence, may be explained by particular functional hemodynamic needs in the examined population of Trieste, as well as by vascular developmental reasons.

Calcium ethylenediaminetetraacetate toxicity in the rat: ultrastructural effects on skin collagen.

The effect of calcium ethylenediaminetetraacetate (CaEDTA) i.v. infusion on skin ultrastructure was studied in the rat with the aid of transmission electron microscopy. High magnification electron micrographs of collagen fibrils were analysed with a computer aided image analyser, in terms of the Gaussian distribution of fibril diameter and the distance between cross striations of collagen fibrils (D-spacing). CaEDTA caused marked depletion of collagen fibrils in the skin. The collagen fibrils from CaEDTA treated rats exhibited significant increases in D-spacing (about 30%) and diameter (about 40%) compared to saline treated controls. These findings are consistent with earlier published biochemical data indicating that CaEDTA enhances collagen degradation in the rat.