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Biomedical subjects

J H Fischer

Publications and source records attributed to J H Fischer.

At least 91 records · Page 5Linked to original sources
PubMed1980

[Influence of piridoxilate on the energy metabolism of normothermic ischemic organs in the rat].

In Wistar rats thermocontrolled normothermic ischemia of the whole body was induced 20 min after i.p. injection of 300 mg piridoxilate (Glyco-6) per kg body weight or Ringer's solution in a control group. Piridoxilate pretreatment did not influence the amount of total adenine nucleotide loss in 30 min of normothermic ischemia of forebrain, skeletal muscle, liver or kidney but resulted in a significantly higher loss in myocardium and lung. A positive effect on the conversation of energy rich substances was found only in the skeletal muscle (creatine phosphate content). Significant effects on substrates of glycolysis were found only in myocardium and lung but in the myocardium also a higher accumulation of lactate occurred.

Adenosine Triphosphate↗
PubMed1979

Free fatty acid and glucose metabolism during hypothermic perfusion of canine kidneys.

Canine kidneys were subjected to continuous nonpulsatile perfusion using 200 ml of a perfusate containing 50 g/l albumin. When optimal oxygenation was achieved, perfusate K+ contents were unchanged for 24 h, indicating adequate membrane function but tended to increase thereafter. Lowered oxygen pressures resulted in significant cellular K+ loss during the first hours of perfusion. During oxygenated perfusion, glucose and free fatty acids (FFA) were oxidized in considerable amounts with a preferential consumption of octanoate. A capacity for long-chain FFA oxidation became obvious when the octanoate had been used up, but the amount of these FFA in the perfusate depended preferentially on FFA being liberated from tissue lipids during the 1st day of perfusion. Glucose consumption rates were highest during the first 2 days of perfusion but the subsequent reduction of the metabolic rate was not accompanied by an accumulation of lactate. Thus medium-chain FFA and glucose should be supplied to the continuously perfused kidney in hypothermia and optimal oxygenation of the perfusate should be guaranteed. However, it seems to be unnecessary to supply exogenous long-chain FFA.

Albumins↗
PubMed1979

[Hypothermic storage under aerobic conditions--the effect of different flushing solutions on kidney functional recovery].

Canine kidneys (n = 17) were flushed with COLLINS (C2), SACKS II, LAMBOTTE (KMgS), ROSS (hypertonic citrate), or RINGER glucose-mannitol solution following a 30-min period of normothermic ischemia. After 24 h hypothermic preservation with retrograde oxygen persufflation (ROP) and autotransplantation, the immediate functional recovery was determined using inulin and PAH clearance methods and compared with the normal contralateral kidney. While a good functional recovery was found in the COLLINS group, significantly exceeding results from hypothermic ischemic storage preservation, in experiments using other flush solutions ROP preservation resulted in only a small immediate function. Thus the experiments indicate that COLLINS solution C2 is the optimal flush solution for ROP preservation.

Aerobiosis↗
PubMed1978

[Metabolic status of hypothermically stored dog kidneys with various perfusion solutions and ischemia pretreatment].

In experiments on canine kidneys, cortical edema formation during hypothermic storage following a period of normothermic ischemia of up to 30 min duration was - according to the osmolality of the perfusion fluid - lower after flush perfusion with Sacks II solution than with Biotest-"Collins" solution or Ringer-mannitol solution, which resulted in the highest edema. The adenine nucleotide content fell corresponding to the duration of the hypothermic storage or the duration of an initial normothermic ischemia, but only small further changes were found during storage following initial normothermic damage. Moreover, with respect to the maintenance of nucleotide contents the strong hyperosmolar intracellular solutions were not superior to Ringer-mannitol solution of 330 mosmol/liter.

Adenine Nucleotides↗
PubMed1978

[Effect of adenosine and inosine on the metabolic status of preserved kidneys].

Isolated rat kidneys were preserved by continuous perfusion or retrograde oxygen persufflation in a medium of the extracellular type with and without addition of adenosine or inosine at 6 degrees C. After 4 and 24 hours of preservation the metabolic states was analysed. In the kidneys preserved by continuous perfusion, only adenosine was able to slow down the loss of nucleotides. With the retrograde oxygen persufflation the stock of high-energy phosphates could be preserved in any case, but no increase in the nucleotide content by neosynthesis was achieved by means of the addition of adenine nucleotide precursors.

Adenine Nucleotides↗
PubMed1977

[Studies on the relationship of maturity to the tolerance of ischemia].

In newborn rabbits during asphyxia caused by ligature of the trachea circulation was maintained 2-3 times as long as in adult rabbits because in contrast to the adults myocardial energy loss in asphyxia is rather low caused by a small energy consumption for circulatory work. In the cerebral cortex of newborn rabbits glycolysis is able to meet a good part of energy demand, with the energetic situation predominantly depending on glucose supply by maintenance of circulation. Thus in addition sufficient blood glucose levels deliberated from glycogen stores in liver and lung are an important factor for the central nervous revivability. Kidney and skeletal muscle tolerate anaerobic periods for rather long time because of their high glycogen stores and low metabolic activity but do not contribute to glucose supply of other tissues.

Animals↗
PubMed1976

[Influence of fatty-acid and glucose content of the perfusate on the energy metabolism of the preserved canine kidney].

Thirty-seven canine kidneys were preserved by hypothermic low flow perfusion for 24-120 h with solution I containing albumin, free fatty acids, and glucose, or with solution II containing Haemaccel without free fatty acids or glucose. Following 48 h preservation the renal ATP and SAN content was identical in both groups, irrespective of the availability of substrates from the perfusate.

Animals↗
PubMed1975

[Cerebral blood flow in rabbits during hypoperfusion of the brain. Flow distribution and methodological problems (author's transl)].

Brains of rabbits were perfused by arterial blood via the internal carotids after ligation of vertebral and external carotid arteries. The effect of the reduction of cerebral perfusion volume on cerebral blood flow was studied by recording the clearance of Krypton-85 from the brains. The clearance curves obtained by recording the gamma radiation of the Krypton-85 represented the sum of tissue clearances from the whole brain (about 10 g) and about 45 g of extracerebral tissue and so were not representative of cerebral or cortical bloow flow. Using external beta-counting the cortical blood flows calculated from the tissue-clearance curves reached mean values of 87 and 159 ml/100 g/min in perfusions with 12 and 18 ml/min respectively. But during reduced cerebral perfusion (2 ml/min) the clearance curves gave cortical blood flow values of 56 ml/100 g/min on the average and so exceeded the values calculated from the perfusion volume (2 ml/min) and the brain-weight (10 g) two to three times. It is concluded that regions of nonperfusion exceeding 50% of the cerebral tissue coexisted with adequately perfused areas. In hypoperfusion the cortical metabolic state was sufficiently correlated with the perfusion volume, but no correlation existed with the cortical blood flow calculated from the clearance curves.

Animals↗
PubMed1975

Metabolic patterns in several tissues of newborn rabbits during ischemia.

The metabolic states of various tissues of newborn rabbits were studied before and after periods of ischemia of 5-40 min. The contents of substances of the energy distributing adenylic acid-creatine phosphate system as well as glycogen, glucose and lactate were determined and the results are discussed in comparison with the well-known values from ischemic tissues of adult rabbits. The preservation of high energy phosphates as well as the rate of glycolytic energy production during the course of ischemia was quite identical in the myocardium of newborns and adults in contrast to the different ability of newborn and adult rabbits to maintain circulation in anaerobic conditions. In the central nervous system the ATP contents decreased to very low levels within a few minutes in both groups although the glycolytic energy production was rather different. But the larger amounts of adenine nucleotides present in the newborns at any time of ischemia indicate a better chance of postischemic recovery. In the livers and the kidneys of the newborns higher rates of glycolytic energy production led to better preservation of the energy-rich substances while in skeletal muscle and the lung only slight differences occurred between newborns and adults.

Adenine Nucleotides↗
PubMed1975

[Effect of pO2 in perfusate on metabolism of preserved dog kidneys].

In 48 canine kidneys submitted to an ischemia of 2 min duration normal cortical ATP values with a nearly unchanged content of total adenine nucleotides (SAN) were resumed by a five minute gravity perfusion. During the following 24 hours of low flow perfusion at 6 degrees C the extent of preservation of ATP and SAN correlated with the arterial oxygen pressure of the perfusate.

Adenine Nucleotides↗