Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
--------
Question: Abstract: The relationship between the perfusion flow rate and cerebral oxygen consumption during deep hypothermic cardiopulmonary bypass at 20 degrees C was investigated in dogs. In 10 dogs the perfusion flow rate was decreased in steps from 100 to 60, 30, and 15 ml/kg/min every 30 minutes. Although cerebral blood flow decreased as perfusion flow rate decreased, the ratio of cerebral blood flow to the perfusion flow rate increased significantly (p less than 0.05) at a perfusion flow rate of 15 ml/kg/min compared to that at a perfusion flow rate of 100 or 60 ml/kg/min. The arterial-sagittal sinus blood oxygen content difference increased as perfusion flow rate decreased. Consequently, cerebral oxygen consumption did not vary significantly at perfusion flow rates of 100 (0.48 +/- 0.10), 60 (0.43 +/- 0.14), and 30 ml/kg/min (0.44 +/- 0.12 ml/100 gm/min), and it decreased significantly to 0.31 +/- 0.22 ml/100 gm/min at a perfusion flow rate of 15 ml/kg/min. In five dogs the perfusion flow rate was decreased in one step from 100 to 15 ml/kg/min, and after 60 minutes' perfusion at a perfusion flow rate of 15 ml/kg/min, the perfusion flow rate was returned to 100 ml/kg/min. Cerebral oxygen consumption decreased significantly during 60 minutes' perfusion at a perfusion flow rate of 15 ml/kg/min and did not return to its initial value after the perfusion flow rate was returned to 100 ml/kg/min. These data indicate that the optimal perfusion flow rate for the brain during deep hypothermic cardiopulmonary bypass at 20 degrees C appears to be 30 ml/kg/min, with a possible oxygen debt in the brain resulting in anaerobic metabolism if the perfusion flow rate is kept at 15 ml/kg/min or less.

Answer: Optimal perfusion flow rate for the brain during deep hypothermic cardiopulmonary bypass at 20 degrees C. An experimental study.

Question: Abstract: Systemic and splanchnic haemodynamics were studied in patients with cirrhosis who had been classified in three groups (A, B, and C) according to the degree of liver failure (modified Pugh's classification). In patients of group A, cardiac index was significantly lower than that of group C and systemic vascular resistance was higher, but not significantly so, than that of patients with liver failure. Wedged hepatic venous pressure was significantly lower in the former group than in the latter. In patients in group B, corresponding values fell between those of groups A and C. Azygos blood flow averaged 0.477 +/- 0.242 l/min (mean +/- SD) in group A and it was significantly lower than in groups B and C (0.642 +/- 0.224 and 1.061 +/- 0.476 l/min, respectively). In the three groups, acute administration of propranolol induced statistically significant changes in systemic and splanchnic haemodynamics. In patients of group C but not of group B, the mean value of azygos blood flow after propranolol remained significantly higher than in group A. Moreover, the fraction of azygos blood flow to cardiac output decreased in groups A and B while slightly increased in group C. This study shows that in patients with cirrhosis, the degree of liver failure may be a determinant for the haemodynamic responses to drugs acting on portal hypertension.

Answer: Influence of the degree of liver failure on systemic and splanchnic haemodynamics and on response to propranolol in patients with cirrhosis.

Question: Abstract: Allelic sequence variation has been analysed by synthetic oligonucleotide hybridization probes which can detect single base substitutions in human genomic DNA. An allele-specific oligonucleotide (ASO) will only anneal to sequences that match it perfectly, a single mismatch being sufficient to prevent hybridization under appropriate conditions. To improve the sensitivity, specificity and simplicity of this approach, we used the polymerase chain reaction (PCR) procedure to enzymatically amplify a specific segment of the beta-globin or HLA-DQ alpha gene in human genomic DNA before hybridization with ASOs. This in vitro amplification method, which produces a greater than 10(5)-fold increase in the amount of target sequence, permits the analysis of allelic variation with as little as 1 ng of genomic DNA and the use of a simple 'dot blot' for probe hybridization. As a further simplification, PCR amplification has been performed directly on crude cell lysates, eliminating the need for DNA purification.

Answer:
Analysis of enzymatically amplified beta-globin and HLA-DQ alpha DNA with allele-specific oligonucleotide probes.