Paj 1 soti nan 317 rezilta yo
OBJECTIVE
Cerebral hypoxia-ischemia leads to the depletion of ATP. Hypoxanthine, a degradation product of ATP, can be salvaged by hypoxanthine phosphoribosyl transferase (HPRT) and used to reform high-energy purines. Hypothermia conserves ATP in hypoxia-ischemia, possibly by preserving HPRT
The survival time of rats and hamsters in lethal hypoxia was measured after a sublethal exposure and a normoxia break, at the beginning of which purines were administered intraperitoneally in the following dosages: 25 mg/kg hypoxanthine, 50 mg/kg allopurinol, 25 mg/kg adenine. In rats,
During hypoxia there is an increased formation of hypoxanthine from the consumption of ATP; simultaneously the oxidation into uric acid is decreased. The purpose of this study was to determine possible correlations between hypoxanthine concentrations in the amniotic fluid and states of fetal
Hypoxanthine, xanthine, inosine, urate and uridine, were measured in 149 samples of umbilical cord plasma using high pressure liquid chromatography. In spite of a good correlation with the simpler oxygen consumption method for measuring hypoxanthine, there was no clear discrimination between hypoxic
Hypoxia is one of the commonest causes of perinatal morbidity and mortality. The worst affected are tissues with high oxygen consumption, in particular nervous tissue (Trojan 1978). Criteria enabling prompt and reliable evaluation of the length and intensity of hypoxia are therefore being sought
To determine the suitability of plasma hypoxanthine as a marker of tissue hypoxia, we studied the relationship of arterial plasma hypoxanthine and blood lactate concentrations to the cumulative O2 deficit during hypoxemia and low cardiac output (hypoxic and stagnant hypoxia, respectively). Eight
Tissue hypoxia was induced in one group of dogs by clamping of the endotracheal tube and in another group by artificial ventilation with a mixture of nitrogen and air. The hypoxanthine concentration of venous and arterial plasma increased significantly during severe hypoxemia. When the hypoxemia was
In order to evaluate the concentration of hypoxanthine in the cord blood as an indicator of intrauterine hypoxia, hypoxanthine was determined in the arterial and venous cord blood of 49 randomly chosen newborns and in the peripheral venous blood of their mothers. In addition, 5 young, nonpregnant
Hypoxemia was induced in pigs by artificial ventilation with 7% oxygen. Death occurred after 21--99 min (mean 48 min). The plasma hypoxanthine and base deficit concentrations increased linearly during hypoxemia and were significantly elevated after 5 min compared to initial values. The correlation
Hypoxanthine levels were determined in both venous and arterial cord blood of 42 neonates. Two methods were compared, a PO2 electrode determination and an HPLC (high-pressure liquid chromatography) method. A good correlation was found between the two methods. However, the HPLC method was more
The concentration of hypoxanthine in plasma was suggested as an indicator of hypoxic conditions in newborns. We examined the concentration of hypoxanthine in maternal venous as well as in umbilical cord blood during pregnancy and during and after labor. The concentration of hypoxanthine in the
High altitude-induced hypoxemia in 26 young adults was used to compared hypoxia parameters such as blood lactate, hypoxia-induced electrocardiogram signs, and the recently proposed plasma hypoxanthine concentration. At a PaO2 of 30 mm Hg, no elevation in hypoxanthine and small increase in lactate
Tissue hypoxia was induced in pigs by artificial ventilation with 6% O2 in N2 for 18 min. Base deficit, lactate and hypoxanthine increased linearily during this period, and were significantly higher than initial values in the course of 6 min of hypoxemia. High correlation coefficients between
The possibility of detecting past hypoxia during the first 2 h after birth by means of blood analyses of hypoxanthine, lactate, base deficit, and pH was investigated in six infants with a 1 min Apgar score of less than or equal to 4. Reference values for the four biochemical variables were obtained
The effect of intra-uterine hypoxia on the hypoxanthine and lactate concentration in fetal sheep with catheters chronically implanted was investigated. Experiments were conducted on five fetuses. Sixty-four blood samples from nine hypoxic and recovery periods were analysed. A significant increase of