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 296,593 document(s) hit in 31,850,051 MEDLINE articles (0.03 seconds)

The content of nicotinamide coenzymes (NAD, NAD-H, NADP, NADP-H) was studied in the brain, heart and liver tissue of the newborn rats kept in hypoxic gaseous medium with a 4% oxygen content for 2 1/2 hours. There was a marked reduction of NAD content, an accumulation of NAD-H and a more than two-fold fall of the NAD/NAD-H ratio particularly marked in the brain and heart. A reduction of the NADP-H values chiefly in the liver and of the general pool of NAD-phosphates in the tissues of the newborn rats under study occurred under the same conditions. The data obtained led to the conclusion that oxygen deficiency had a significant influence on the concentration and the ratio of the nicotinamide coenzymes in the tissues of newborn rats, that in its turn led to the changes in the level and the direction of the redox processes under the conditions of hypoxia.
Biull Eksp Biol Med 1976
PMID:[Effect of hypoxia on the concentration of nicotinamide coenzymes in the tissues of newborn rats]. 1 78

This paper describes the radiosensitizing effects of diatrizoic (DA) and iothalamic (ITA) acids and of iodipamide (IP) on the survival of E coli B/r irradiated with X-rays and with high-intensity electron pulses. All compounds at concentrations between 10 and 50 mM display a strong sensitizing effect in the presence of oxygen (DMF between 0-1 and 0-3) and are much less effective in nitrogen. In N2O the degree of sensitization is intermediate between oxygen and nitrogen. The situation is the same at pH 7 or 5-6. Solutions of DA, ITA and IP irradiated at pH lower than 6 become highly toxic to bacteria added after irradiation, for several hours after X-irradiation or several minutes after pulsed irradiation. The maximum toxic effect occurs with 2 krad of X-ray and with 6-8 krad of electrons. Oxygen must be present in order to observe the bactericidal activity. This is not affected by scavenging hydrated electrons with nitrate, but is completely cancelled by scavenging OH radicals with formate. It is also cancelled by adding thiosulphate to the irradiated solutions immediately before the bacteria. In the presence of nutrient broth, the radiosensitizing effect is absent after irradiation with pulsed electrons; whereas after X-irradiation it is reduced when the concentration of sensitizers is 50 mM. The experimental data appear to be compatible with a mechanism operated by short and long-lived transients resulting from the radiolysis of iodinated contrast media.
Int J Radiat Biol Relat Stud Phys Chem Med 1977 Jan
PMID:Iodinated radiological contrast media as radiosensitizers. 1

1. Oxygen consumption and central haemodynamics were recorded at rest and during exercise in fifty-one men with essential hypertension (W.H.O. stage I) and repeated after 1 year on a single drug: alprenolol (n equals 10), atenolol (13) metoprolol (12) and timolol (16). 2. Mean arterial pressure was significantly reduced in all groups at rest (11-18%) and during exercise (5-11%). Heart rate was significantly reduced in all groups (20-28%) at rest and (17-26%) during exercise. Owing to increase in supine resting and exercise stroke volume in the alprenolol and atenolol group, cardiac index decreased less than heart rate---in contrast to the timolol group where cardiac index was decreased 26-32%. The calculated post-treatment total peripheral resistance was significantly increased at rest and during exercise in the timolol group. In the other groups the total peripheral resistance was significantly increased at rest when sitting, but not at rest when supine and during exercise. 3. It is concluded that the major haemodynamic changes induced in subjects with moderate and mild essential hypertension by these different beta-receptor blockers are the same, but that minor differences exist with respect to effect upon stroke volume and total peripheral resistance.
Clin Sci Mol Med Suppl 1976 Dec
PMID:Haemodynamic long-term effects of beta-receptor-blocking agents in hypertension: a comparison between alprenolol, atenolol, metoprolol and timolol. 1 59

Oxygen availability during cardiopulmonary bypass was assessed in 22 patients under hypothermic and relatively normothermic conditions. The patients were divided into two groups, 17 of whom received ACD blood and 5, CPD blood. The mean P50 for all patients fell from a preoperative value of 25.9 +/- 2.4 (SD) to 15.6 +/- 2.1 during hypothermia confirming a leftward shift of the oxyhemoglobin dissociation curve. Oxygen uptake, calculated from a-v oxygen content differences (avDO2) and flow, was significantly lower during hypothermic bypass (65 +/- 27 ml/min) than during rewarming (121 +/- 41 ml/min). The increase in oxygen affinity during hypothermia was influenced also by changes in acid base and 2,3-DPG concentrations, the changes being similar in both the ACD and CPD groups of patients. During rewarming, however, oxygen availability was increased in the CPD group presumably from significantly increased 2,3-DPG concentrations. A "functional" value of hemoglobin, based upon the effects of the shift of the oxyhemoglobin dissociation curve and, therefore, reflecting the true capacity of hemoglobin to unload oxygen at the tissue level, was calculated. During the hypothermic phase of bypass, this functional hemoglobin was only 4.2 g/100 ml blood, suggesting that, in spite of reduced metabolic demands, oxygenation reserves are minimal.
Crit Care Med
PMID:Oxygen availability during hypothermic cardiopulmonary bypass. 1 30

The optical isomers of alpha-adrenergic receptor antagonists prosympal (2), piperoxan (3), and dibozane (4) were prepared by methods establishing the absolute configuration of each. (2S)-3(2'-Hydroxyphenoxy)-1,2-propanediol ditosylate (10) was prepared from (2R)-3-tosyloxy-1,2-propanediol acetonide (6). Intramolecular displacement afforded (2S)-tosyloxymethylbenzodioxan [(2R)-11]. Reaction of (2R)-11 with the appropriate amine (diethylamine, piperidine, or piperazine) afforded the 2S isomers of 2, 3, and 12, respectively. Reaction of (2S)-12 with (2R)-11 afforded the SS isomer of 4. Reaction of (2S)-3-benzyloxy-1,2-propanediol ditosylate (14) with catechol (NaOMe) afforded (2R)-benzyloxymethylbenzodioxan (15). Subjecting 15 to hydrogenolysis, tosylation, and displacement with the appropriate amine afforded 2R isomers of 2, 3, and 12. Reaction of (2R)-12 with (2S)-11 afforded (RR)-4. Reaction of (2R)-12 with (2R)-11 afforded meso-4. The S isomers were more effective antagonists to the alpha-adrenergic response of methoxamine-induced contraction of rabbit aortic strips by twofold in 2 and 18-19-fold in 3 and 4. meso-4 was as effective as the SS isomer of 4. The results are interpreted in terms of a similar conformational distribution of aminoalkyl, oxygen, and aromatic functional groups of the (S)-benzodioxans and (R)-epinephrine.
J Med Chem 1977 Jul
PMID:Absolute configuration of glycerol derivatives. 4. Synthesis and pharmacological activity of chiral 2-alkylaminomethylbenzodioxans, competitive alpha-adrenergic antagonists. 1 49

The study was undertaken to investigate the acute haemodynamic effects of bunitrolol (0-2-hydroxy-3-(tert.butylamino)-propoxy)-bity. Right and left heart catheterization was performed in eleven patients with documented coronary artery disease. After bunitrolol (10 mg i.v.), there was a statistically significant decrease in left ventricular and aortic systolic pressures left ventricular end-diastolic pressure, aortic diastolic and mean pressures, pressure-rate product and compliance index (delta P/delta V). Left ventricular dp/dt, left ventricular dp/dt over isovolumic pressure, systemic resistance and heart rate tended to decrease, stroke volume and left ventricular stroke work index tended to increase, without statistical significance. Cardiac index showed individual variations, the mean values for the group being unchanged. Correlation of left ventricular end-diastolic pressure and left ventricular stroke work index showed a shift toward improved ventricular function curve in most cases, deterioration in no instance. Supine exercise was performed in ten patients. Angina occurred in nine patients; in five only before and in four before and after beta-blockade. Post-drug exercise heart rate, pressure-rate product and left ventricular end-diastolic pressure were significantly lower, the latter also in the four patients who still presented exercise angina. It is concluded that certain beta-blockers can improve cardiac performance at rest and during exercise in patients with coronary artery disease. This is explainable on the basis of a more favourable balance between oxygen supply and demand, together with a less marked negative inotropic effect due to the partial agonist activity of the agent used in the study.
J Int Med Res 1976
PMID:Evidence for improved cardiac performance after beta-blockade in patients with coronary artery disease. 1 74

The effect of oral disodium ethane-1-hydroxy-1,1-diphosphonate, EHDP (20 mg kg-1 day-1) and placebo given for 28 days on plasma inorganic phosphate (Pi) red cell 2,3-diphosphoglycerate and oxygen affinity of hemoglobin was evaluated in 14 insulin-treated diabetics and 5 healthy volunteers. EHDP significantly increased mean Pi (diabetics: 1.18 to 1.67 mmol/l, p less than 0.01, controls: 1.03 to 1.71 mmol/l, p less than 0.02) and P50 at in vivo pH of the oxyhemoglobin dissociation curve (diabetics: 25.4 to 26.6 mmHg, p less than 0.02; controls: 26.3 to 28.9 mmHg, p less than 0.02). Pi and P50 were correlated in both diabetics and in controls (p less than 0.05). 2,3-DPG increased when the diabetics were on EHDP (p less than 0.005). The study emphasizes the importance of Pi on red cell function and indicates that an elevation of Pi tends to counteract the defect in oxygen release capacity of the red cells in diabetic subjects.
Adv Exp Med Biol 1977
PMID:Effect of the diphosphonate EHDP on plasma inorganic phosphate and hemoglobin oxygen affinity of diabetic and healthy subjects. 1 49

Model systems of respiratory infection in mice were established with Streptococcus pneumoniae, influenza virus, and Mycoplasma pulmonis. The LT50 for S. pneumoniae was 2 1/2 days, for lethal influenza 6 days, and for M. pulmonis 5 days. Morbidity in sublethal influenza infections reached a peak during days 5 to 10, with recovery indicated by the third week. The course of each pulmonary infection was followed by use of the animal's maximal ability to consume oxygen (VO2max by determining the weight, compliance, and stability of the excised lung, and in some cases by following O2 consumption of minced tissue. Depression of VO2max began early in each infection; reductions ranged from 9% at the peak of sublethal influenza infection to 50% 12 to 48 hr before the LT50 of fatal infections. The depressions were not relieved by 100% O2. The noninvasive VO2max test, evoked by cold air, was simple, rapid, and reproducible and appeared to serve as a quantitative measure of over-all function during infection. Each type of infection caused an increase in lung weight, with the largest noted during fatal Mycoplasma illness and lethal influenza. The effects on lungs by influenza and M. pulmonis infections were similar but could be differentiated from those with S. pneumoniae. With sublethal influenza, CL was reduced 30% between days 5 to 10, with recovery by the third week. Ctis was not affected. M. pulmonis infections and lethal influenza caused depressions in CL of over 60% by day 4 but only a 30% decrease in Ctis. The data suggest that the decreased compliance in influenza and M. pulmonis infections was due primarily to increased surface tension. In contrast, S. pneumoniae did not affect compliance.
J Lab Clin Med 1978 Feb
PMID:Oxygen uptake and lung function in mice infected with Streptococcus pneumoniae, influenza virus, or Mycoplasma pulmonis. 2 1

The following conclusions can be made on the basis of this work: 1) Measurements of skeletal muscle oxygen tension provide an excellent index of tissue perfusion in haemorrhagic shock. 2) Correction of cardiac output and arterial blood oxygen tension in haemorrhagic shock does not necessarily ensure normal tissue oxygenation. 3) In haemorrhagic shock adequate replacement of blood loss using a balanced salt solution in addition to blood replacement is an integral part of the fluid management. 4) Correction of hypovolemia with an equivalent volume of a plasma expander and subsequent reinfusion of shed blood also returns tissue perfusion to normal. However, this treatment results in marked haemodilution and correction of extracellular fluid loss remains inadequate.
Adv Exp Med Biol
PMID:Skeletal muscle PO2: indicator of peripheral tissue perfusion in haemorrhagic shock. 2 85

Hemoglobin Hb) Creteil alpha2beta(2)89 (F5) Ser leads to Asn is a high oxygen-affinity variant that has a low cooperativity, a decreased Bohr effect, and does not interact with diphosphoglycerate (DPG) (1). This hemoglobin variant was silent by routine electrophoresis. Careful analyses of the oxygen dissociation curves of erythrocytes, determined at varying pH and Pco2 in fresh and DPG-depleted cells, gave extensive information on the abnormal function of the mutant hemoglobin. From the O2 dissociation curves of the erythrocytes of the heterozygous subject it appeared that Hb Creteil is inappropriate for O2 transport to the tissues because it remained completely saturated with O2 at normal physiologic levels of Po2. In-vivo measurements showed that only one half of the total hemoglobin present actually participated in oxygen transport. Polycythemia should therefore be maintained within clinically tolerable limits because it helps to keep arterial Po2 and Pvo2 close to their normal values and thus protects the individual from a permanent increase in blood flow.
Ann Intern Med 1978 Jun
PMID:Hemoglobin Creteil: oxygen transport by erythrocytes. In-vitro and in-vivo studies in a high oxygen-affinity mutant hemoglobin. 2 32


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