Reduced Oxygen Supply Research Articles

Metabolic control of circulation. Effects of iodoacetate and fluoroacetate.

The circulatory effects of selective metabolic inhibition of glycolysis and of the tricarboxylic acid cycle by iodoacetate and fluoroacetate were studied in intact chloralose-anesthetized dogs. Pulmonary arterial blood pressure and vascular resistance increased after administration of both inhibitors, but neither systemic hemodynamics nor myocardial contractility changed significantly. Coronary blood flow did not change after iodoacetate administration but increased four- to five-fold after fluoroacetate. Administration of normal saline had no effect on any of the parameters. The changes in pulmonary arterial blood pressure and coronary blood flow after fluoroacetate were not mediated via the autonomic nerves or adrenergic neurohumors because they still occurred after autonomic nervous system inhibition. Neither myocardial oxygen consumption nor left ventricular work changed. A selective increase in myocardial blood flow also occurred in conscious dogs after fluoroacetate administration; hepatic artery flow was reduced, but other organ flows did not change significantly. These results indicate that pulmonary pressor and coronary dilator effects may be produced in intact dogs by selective metabolic blockade, in the absence of reduced oxygen supply or impairment in the electron transport system. These results also suggest that the increases in pulmonary arterial blood pressure, coronary blood flow, and cardiac output that occur during hypoxia probably are related to separate metabolic events in the tissue.

Stimulation of Avena coleoptile growth by reduction of oxygen supply

The growth of Avena sativa L. coleoptiles was accelerated by reduction of the O2 concentration in the surrounding atmosphere. Cell-wall extensibility was increased in close relation to the increase in elongation, 6-8% O2 giving the optimal effect in either case. Growth promotion by reduced O2 concentration and by auxin (indole-3-acetic acid; IAA) were additive, at least at lower auxin concentrations.This response to reduced O2 concentration was also present in sections pretreated with cycloheximide for 2 h, although such sections showed no response to applied IAA. No significant change was observed in auxin transport under reduced O2 supply. It is suggested that the acceleration of cell elongation and the loosening of cell wall by reduced O2 supply are due to a mechanism which is not directly dependent on auxin-induced growth. We propose to designate this acceleration of growth under reduced O2 concentrations as oxygen-sensitive growth.

Effects of neutral aminoacids injected into cerebrospinal fluid space on glucose metabolism in the rat brain

In order to ascertain whether the hypothermia induced by neutral aminoacids could depend upon a reduced oxygen supply to the brain, rats received, through a cannula chronically implanted into the lateral ventricle, glycine, GABA and taurine (20 μmol 250 g body weight). The brain levels of glucose, lactate, pyruvate and glycogen and those of glucose and lactate in the blood were determined during hypothermia. The concentration of these metabolites and the brain blood volume of cannulated animals were similar to those of unoperated controls. No consistent biochemical evidence of brain hypoxia was found after glycine, taurine and GABA administration. It is concluded that the effect exerted by the injection of neutral aminoacids into the CSF on thermoregulation is dependent on their direct action on nervous centres.

Effect of reduced oxygen supply and of inhibitors of SH-groups on the staining of upper epidermal cells ofAllium cepa with neutral red

Der anAllium-Epidermen unter Deckglas eintretende „Asphyxieeffekt“ zeigt zwischen pH=7,1 und 8,0 eine Abhangigkeit derart, das er bei niederem pH-Wert rasch (nach 2—4 Minuten), mit steigendem pH-Wert aber immer langsamer (bei pH=8,0 nach 10 Minuten oder spater) einsetzt.

A new aspect of the role of blood 5′-adenosine triphosphate in fetal and neonatal hypoxia

Ninety-five newborn infants were examined immediately after delivery. Potentiometric blood gas measurements demonstrated that increased metabolic acidity in umbilical blood was commonly accompanied by a reduced oxygen supply to the fetus during the previous stage of labor. There was also a good correlation between metabolic acidity and the general condition of the neonate as judged by the clinical score. Furthermore, metabolic acidosis was accompanied with a moderate increase of the hemoglobin and hematocrit values. In all 95 neonates, 5′-adenosine triphosphate (ATP) determinations were carried out by a conventional enzymatic test. ATP levels of umbilical vein blood were usually significantly higher than those of umbilical artery blood (P < 0.01 and < 0.001), indicating a periodicity of ATP metabolism synchronized to blood circulation. In the newborn infants with metabolic acidosis, the characteristic ATP difference was abolished by a relative increase of the ATP level in umbilical artery blood. Similar results were obtained for the ATP levels in blood cells. Since higher concentrations of ATP enhance oxygen delivery from hemoglobin, one may speculate that the increased ATP levels found in the blood cells of the umbilical artery blood of newborn infants with metabolic acidosis favor oxygen release to the hypoxic tissue of the fetus and the newborn infant.

Myocardial utilization of carbohydrate and lipids

Myocardial utilization of carbohydrate and lipids

Bulking of dairy waste activated sludge

The phenomenon of bulking of a dairy waste activated sludge was studied in relation to known and estimated data concerning two types of microorganisms involved in the mechanism of bulking, viz. Sphaerotilus and Arthrobacter-like bacteria. Reduced oxygen supply, as resulting from the high dissimilation rate of the carbohydrate fraction of the dairy waste, together with the ability to accumulate storage compounds and the discrepancy between the potential and actual C/N ratios of this waste, were considered to be the main factors in stimulating growth of Sphaerotilus, and thus to be responsible for bulking. Alteration of the nutritional conditions caused an improvement of the growth of Arthrobacter-like bacteria and this led to a pronounced relative suppression of Sphaerotilus, as a result of which the settling properties of the sludge were restored.

Relation Between Soil Aeration and Ethyl Alcohol Accumulation in Xylem Exudate of Tomatoes

AbstractExperiments were designed to measure the influence of soil oxygen stress and other environmental variables on the accumulation of ethanol in tomato plants. Oxygen stress was imposed by varying the soil moisture tension over a narrow range of low values. Ethanol was observed in the exudate samples when the rate of oxygen diffusion through the soil solution fell below 38 × 10‐8 g.cm.‐2min.‐1. A small reduction in oxygen supply below this value was associated with a large increase in ethanol. In cases of severe oxygen stress the physiological concentration of ethanol was sufficient to be toxic. Plants bearing flowers accumulated more ethanol than younger ones and those subjected to oxygen stress in bright light accumulated more ethanol than those in the dark.

Effect of Reduced Oxygen Supply on Frost Hardening in Plants

EXPERIMENTS described by Siegel et al.1 show that cucumber seedlings are capable of surviving a temperature Of −10° C if grown previously for three weeks in an atmosphere of 2 per cent oxygen and 98 per cent argon. This is a most interesting phenomenon, as cucumber normally shows little or no capacity for frost resistance.

A LONGITUDINAL FOLLOW-UP OF NEONATAL APNEA.

The developmental sequelae of perinatal anoxia have been investigated and reviewed by numerous authors. In view of the potential vulnerability of the central nervous syste~m at the moment of birth, various circumstances, which in one way or another reduce oxygen supply to nervous tissue, have been implicated as causative factors leading to a host of later developmental disturbances. Mental retardation, behavior disorders, learning problems, and neurological defects ranging from cerebral palsy to impaired vision have all been studied in relation to delayed onset of respiration at delivery and/or reduced oxygen supply to the fetus as a result of obstetrical complications such as premature separation of the placenta. It is not surprising that, given the methodological and conceptual complexities of this problem, the findings are varied and, at times, contradictory. Bailey (3) has presented a comprehensive review of the literature. Within the general category of human clinical studies, he distinguishes three classes of research design: In the retrospective study, a sample of damaged, disturbed, or defective individuals is chosen, sometimes paired with matched controls. The investigator then seeks out the birth records of these individuals and determines whether a significantly greater proportion of them were reported as being anoxic at birth than would be found or expected in a normal population. In the prospective-retrospective study, the sample is selected by examining existing birth records to find two contrasting groups, one having sustained

ON THE INTERMEDIATE METABOLISM OF CARBOHYDRATES IN THE BRAIN OF HYPERTENSIVE AND POSTAPOPLECTIC PATIENTS.

On 25 cases of hypertension and 16 cases of postapoplectic patients with hypertension the cerebral carbohydrate metabolism was estimated, simultaneously with the cerebral hemodynamics, using Kety's N2O method. The cerebral glucose consumption was generally smaller in these patients than that of healthy subjects. It was found not to stand in such a close relationship with cerebral oxygen consumption as it was the case in healthy subjects. It depends on the glucose content in arterial blood to some extent. Some disturbances are presumed in the blood glucose transfer into the brain tissue. No significant difference was detected between the hypertensive and the postapoplectic subjects in respect of the cerebral glucose consumption. An increased lactic acid forma-tion was presumed in the brain of these patients, especially in the hypertensive patients: The amount of lactic acid carried out of the brain was in many cases too large to be explained by the decrease in oxidized part of blood glucose owing to the reduced oxygen supply.

Conservative Management of Hemothorax with Presentation of an Illustrative Case

The diagnosis of hemothorax may be obvious in case of external Injuries, or difficult to detect when concealed. Should the symptoms, physical examination and x-ray suggest a hemothorax, diagnostic aspiration is necessary for confirmation. Early shock is the rule. Anoxia also supervenes early. The shock is caused by local injury and hemorrhage. Early in shock, local pain and nervous factors are significant. Pallor; rapid, shallow breathing; small, rapid pulse; cyanosis, fall of blood pressure; and apathy appear In proportion to the amount and rapidity of the bleeding. With the loss of blood, there is a feeling of faintness, air hunger, rapid heart action, and coldness of the extremities. Blood volume, red blood count, and hemoglobin are reduced. At first the blood pressure is usually well maintained, but later falls. Cyanosis may not be evident, since it depends upon the grams of reduced hemoglobin present. A sequence of events follows the accumulation of fluid or air in the pleural space. First, there is collapse of the lung on the side of the bleeding. The extent depends upon the presence of adhesions and of the amount of thickening of the pleura. Continuous bleeding builds up pressure, which is exerted against the mediastinum. Unless the mediastinum is firm, it readily shifts to the opposite side and partial collapse of that lung takes place. Local stasis results from pressure upon the great vessels and heart. Since the pulmonary system has a pre$sure one fifth that of the general circulation, control of bleeding from this source is easier; however, the constant movement of the lung may aggravate the bleeding. A vessel from the systemic circulation tends to bleed more violently because of its higher pressure. With increased intrapleural pressure, there is increasing dyspnea and cough, often with expiratory grunt. It is known that with gross hemorrhage rales appear on the side opposite the bleeding. This transudation of fluid across the epithelial surface is the result of pressure upon the heart and great vessels, reduced oxygen supply to tissues, and dilution of the blood plasma with reduction in the osmotic pressure. The most sIgnificant physical signs associated with accumulation of blood are absent breath sounds and dullness to flatness on per

STATE OF MOTOR CENTERS IN CIRCULATORY INSUFFICIENCY

In a previous communication by an associate and us1the fusion frequency of flicker was reported as decreased in circulatory insufficiency (hypertension or heart disease). This decrease is probably due to a reduced oxygen supply to the central nervous system. Fatigue develops first in the sensory centers, and it spreads from there to involve other parts of the central nervous system. Visual centers are especially sensitive to the lack of oxygen. Hence the use of the fusion frequency of flicker might be expected to uncover changes not detectable by other methods. (For a review of pertinent literature, see the previous communication.1) The effect of fatigue on the motor centers has much practical significance, and its measurement is important, since, after all, performance is the objective clinical evidence of fatigue. Therefore, a combined investigation of a sensory and a motor function should enable us to come to some conclusions

The Favorable Effect of Reduced Oxygen Supply Upon the Germination of Certain Seeds

American Journal of BotanyVolume 13, Issue 2 p. 159-166 Article THE FAVORABLE EFFECT OF REDUCED OXYGEN SUPPLY UPON THE GERMINATION OF CERTAIN SEEDS Toshitaro Morinaga, Toshitaro Morinaga Boyce Thompson Institute for Plant Research, Inc., Yonkers, New YorkSearch for more papers by this author Toshitaro Morinaga, Toshitaro Morinaga Boyce Thompson Institute for Plant Research, Inc., Yonkers, New YorkSearch for more papers by this author First published: 01 February 1926 https://doi.org/10.1002/j.1537-2197.1926.tb05875.xCitations: 29AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume13, Issue2February 1926Pages 159-166 RelatedInformation