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Biomedical subjects

G P Novelli

Publications and source records attributed to G P Novelli.

At least 19 recordsLinked to original sources
PubMed1992

Neutrophils as mediators of human skeletal muscle ischemia-reperfusion syndrome.

Nine patients with aortic aneurysm undergoing arterial reconstruction with temporary aortic occlusion were studied. Since a typical condition of ischemia-reperfusion of the muscles of the lower limbs was created during this surgery, muscle biopsies from the right femoral quadriceps as well as blood samples from the homolateral saphenous vein were taken: (1) before clamping of the aorta, (2) just before declamping, and (3) 30 minutes after reperfusion. Light microscopy revealed a consistent granulocyte infiltration in the ischemic and reperfused skeletal muscle. Ultrastructural damage to the muscle fibers was seen during ischemia and became more severe upon reperfusion. The recruitment of granulocytes into the muscle tissue paralleled the activation of the blood complement system and an increase in circulating neutrophils. Although a spontaneous superoxide anion (O2-) generation from such granulocytes cannot be proved, upon stimulation with formyl-methionyl-leucyl-phenylalanine neutrophils showed a reduced ability in O2 free radical production at the end of ischemia and enhanced O2- generation at reperfusion as compared with the controls. All these findings indicate an active role of granulocytes in the genesis of reperfusion-induced tissue injuries.

Aged↗
PubMed1992

Oxygen radicals in experimental shock: effects of spin-trapping nitrones in ameliorating shock pathophysiology.

BACKGROUND: Circulatory shock is accepted as a consequence of an acute oxygen radical overgeneration. Spin-trapping nitrones inactivate free radicals by forming relatively stable adducts. OBJECTIVE: Three spin-trapping nitrones (N-tert-phenyl-butyl-nitrone; alpha-4-pyridyl-oxide-N-tert-butyl-nitrone; 5-5,dimethyl,1,pyrroline-N-oxide) were tested regarding their role in the pathophysiology and evolution of circulatory shock in rats. DESIGN: Prospective, randomized, controlled trial of spin-trapping nitrones in rats experiencing three different models of circulatory shock. EXPERIMENTS AND RESULTS: In the first group, endotoxic, traumatic, and mesenteric artery occlusion shock (all 100% lethal in control experiments) was prevented by the ip administration of N-tert-phenyl-butyl-nitrone (150 mg/kg); alpha-4-pyridyl-oxide-N-tert-butyl-nitrone (100 mg/kg); or 5-5,dimethyl,1,pyrroline-N-oxide (100 mg/kg). However, the evolution of shock was unaffected by the same compounds when all three nitrones had been previously inactivated by exposure to light and air. In the second group, microcirculatory derangements that were provoked by endotoxin and were observed in the mesocecum of rats were completely prevented by pretreatment with either peritoneal administration of each of the three nitrones or by their topical application to the microscopic field. While the rats survived after systemic treatment, those rats receiving topical nitrones died from endotoxic shock. In the third group, cell-membrane stiffness (a sign of peroxidative damage) was measured by spin-probes and electron-spin resonance in mitochondrial and microsomal membranes. Cell membranes obtained from shocked rats were more rigid than those membranes of controls. However, the membranes obtained from rats that were submitted to trauma or endotoxin after pretreatment with N-tert-phenyl-butyl-nitrone had normal stiffness. The fourth group of experiments was carried out to quantify ethane (one of the final products of lipid peroxidation) in the exhaled air of shocked rats. Ethane concentrations increased in direct proportion to the worsening of the condition. Pretreatment of the rats with N-tert-phenyl-butyl-nitrone prevented such an increase. CONCLUSIONS: Since nitrones are effective inactivators of oxygen-radicals, or of their secondary radicals, these data confirm the relationship between oxygen-radicals and experimental shock. The therapeutic use of spin-trapping nitrones should possibly be considered for future use in shock.

Animals↗
PubMed1992

[Comparison of crystalloids and hydroxyethyl starch during normovolemic hemodilution. A study of hemodynamics and saturation measurement].

Normovolemic hemodilution at two different hematocrit values was performed in ten patients undergoing major surgery to evaluate changes of DO2, VO2 and CI. A Hct of 38% (low hemodilution) was reached by plasma replacement with ringer lactate infusion. A further hemodilution, a Hct of 30% (high hemodilution), was obtained by hydroxyethyl starch plus ringer lactate (1:2 ratio) infusion. A significant VO2 increase (p less than 0.01) occurred when hydroxyethyl starch plus ringer lactate infusions were employed as compared to ringer lactate alone. No changes in DO2 and CI were observed, the increase in VO2 measured during colloid infusion could suggest a better tissue perfusion and metabolic activity.

Aged↗
PubMed1992

[Inhalation anesthesia in low-flow systems. Clinical evaluation of the kinetics of isoflurane in induction phase].

Closed circuit and low flow anaesthesia offer numerous advantages such as reduction of gas consumption, low cost, and less pollution in both the operating theatre and the environment. These procedures also offer increases in inspired gas humidity and temperature. However the time needed to attain the alveolar concentration MAC 95, is too long. Prefilling the whole circuit, the bellow and the bag with anaesthetic vapours shortens that time without overdosage.

Anesthesia, Closed-Circuit↗
PubMed1991

Exogenous glutathione increases endurance to muscle effort in mice.

Many data suggest an involvement of toxic oxygen radicals in the termination of endurance to muscle fatigue. Being reduced glutathione (GSH), an efficient intracellular physiological antioxidant, experiments have been performed to discover whether exogenous GSH modifies endurance to exhaustive swimming in mice. GSH was administered to mice as a single dose (250, 500, 750 or 1000 mg/kg i.p.) or as repeated doses (250 mg/kg i.p. once a day during 7 days) 10 min before a swimming test to exhaustion. GSH 500, 750 and 1000 mg/kg, increased endurance to swimming by respectively 102.4%, 120.0% and 140.7%. GSH 250 mg/kg did not affect endurance when injected in a single dose but increased it by 103.7% when injected once a day for 7 days.

Animals↗