High Levels Of Carbon Dioxide Research Articles

The effect of physical factors on the rate of respiration of the infective larvae of Strongyloides ratti Sandground, 1925

Dense larval suspensions have a higher Qo2 than dilute ones, probably due to an oxygen debt acquired during preliminary washings. Ammonia (0·1M) did not affect the respiratory rate of the infective larvae of S. ratti. Mechanical agitation of larvae reduced their rate of respiration.The partial pressure: respiration curve of the infective larvae was sigmoidal, that of larval homogenates was a rectangular hyperbola. At low partial pressures of oxygen the respiratory rate depends to a certain extent on the rate of change of the partial pressure.In 100% oxygen the respiratory rate of the larvae is at first stimulated and then falls to its initial level. On returning to air after 100% oxygen, the respiratory rate is at first depressed and then recovers.The infective larvae of S. ratti develop an oxygen debt when kept under anaerobic conditions. During the recovery period, which lasts for about 1 h, the Qo2 may increase by up to 100%.The respiration of the infective larvae increases as the temperature is increased. When larvae are maintained at 37 °C there is a gradual decrease in their rate of respiration and this change is apparently irreversible.The rate of respiration of the larvae is slightly inhibited at low pH values and slightly stimulated at high pH values.Moderate levels of carbon dioxide (5%) have no effect on the respiratory rate of the infective larvae of S. ratti, high levels of carbon dioxide (10–20%), have a definite narcotic effect on the larvae.The respiration of the infective larvae is unaffected by osmotic pressures up to an equivalent of 1% sodium chloride. Above this level the respiratory rate is at first stimulated then decreases.This work was carried out during the tenure of a Medical Research Council Scholarship.

Effects of high carbon dioxide levels on nutrition of sheep.

Nutrient intake and digestibility data were obtained with four yearling wethers during exposures to 4, 8, 12, 16 and 18% CO2 in air for periods of 5 to 7 days. Dry matter intake was not affected by exposure to 4% CO2, but intake was inversely related to CO2 concentration at all other exposure levels. Nutrient digestibility was not influenced by CO2 levels up to 16%. At 16 and 18% CO2 variable decreases in nutrient digestibility were noted. Rapid, labored breathing was observed at the onset of all trials. A return toward normal respiration was noted within 24 hr. at the 4, 8 and 12% CO2 exposures, but at 16 and 18% CO2 the condition persisted throughout the trials.

Effect of. Oxygen and Carbon Dioxide on the Mitochondria of Sclerotium Rolfsh

The number of mitochondria apparently vary with the energy requirements of the cell (see Rouiller 1960). Although swelling and multiplication of mitochondria have been observed to occur in cells, a quantitative analysis of these changes has not been recorded. Matile and Bahr (1968) have recently provided electron micro-scopic evidence of the heterogeneity of density, mass, and volume of the mitochon-drial population in respiring baker's yeast. There are reports in the literature of the complete absence of mitochondria in yeast cells growing under anaerobic conditions (see Marchant and Smith 1968). Griffin and Nair (1968) demonstrated that the growth of Sclerotium rolfsii was inhibited by concentrations of oxygen below 4% and by concentrations of carbon dioxide above 0�03 %. It was, therefore, thought worthwhile to study the changes in mitochondria of this fungus when the cells are subjected to external stresses of low oxygen and high carbon dioxide levels.

Factors Influencing Expression of Oxidant Damage to Plants

This paper suggests that the mechanism that controls resistance of plants to oxidant pollutants may be similar to the one that controls resistance to other extremes in environmental factors. From the literature the following generalizations can be made in regard to the factors that affect the sensitivity of plants to oxidant air pollutants during growth: plants are more sensitive when grown under a short photo-period, a long dark period prior to exposure increases sensitivity; plants grown under low light intensities are more sensitive to ozone and less sensitive to PAN; low temperatures for one to several days prior to exposure reduce sensitivity; plants grown under drought conditions are less sensitive; plants grown under relatively low fertility levels are more sensitive. Sensitivity at time of exposure increases with increasing light intensity. Sensitivity of plants exposed under natural conditions is affected more by light intensity than by temperature. Temperature has an inverse effect on sensitivity, when plants are exposed under controlled lighting conditions. High carbon dioxide levels, at time of exposure, reduce sensitivity. Plants exposed under any soil conditions that produce a water stress in the plant show an increased resistance. Plant sensitivity, at time of exposure, increases with an increase inmore » humidity. Injury from PAN is mediated by a light-sensitive system within the plant. Sulfur dioxide reacts synergistically, with both ozone and nitrogen dioxide, on sensitive plant tissues. 101 references.« less

Lack of Effect of Sodium Bicarbonate on Shell Characteristics

Helbacka et al. (1963) observed a decline in blood pH and a thinning of egg shells when birds were exposed to an atmosphere containing 5% carbon dioxide. These workers concluded that calcification in the shell gland was dependent on blood pH which was lowered by respiratory acidosis caused by the high carbon-dioxide atmosphere.Frank and Burger (1965) reported that sodium bicarbonate in the drinking water of hens resulted in a 6.6% improvement in egg shell thickness. They concluded that the reported increase in egg shell calcification in birds exposed to high levels of atmospheric carbon dioxide was not a result of changes in blood pH but, rather, a result of respiratory acidosis and its resultant effects upon the availability of bicarbonate ions in the shell gland.El-Bousky (1966) reported that, when birds were exposed to a medium range of temperatures, the feeding of sodium bicarbonate improved shell quality.Howes (1966) .

Carbon dioxide in the prevention of air embolism during open-heart surgery.

The factors which are important in the design and use of apparatus for the effective displacement of air by carbon dioxide from chest cavities are examined. High levels of carbon dioxide can be achieved by flowing carbon dioxide at a total flow rate of 51./min. into the chest cavity through two nozzles of 0·5 to 1·0 cm. diameter. The effect of factors which might diminish the carbon dioxide levels is examined.

Effect of high levels of carbon dioxide on pigs infected with porcine enterovirus.

野外で下痢,嘔吐を呈している豚から分離され,しかも実験的にはSPF豚に限って,その上脳内接種の場合のみ発症させる豚エンテロウイルスChico株を用い,高濃度の炭放ガス吸入が発症に及ぼす影響を調べた.SPF豚においては,ウイルスを静脈内接種した直後,30%に炭聚ガスを含んだ空気を1乃至10分間吸入させたものに後肢麻痺,下痢,嘔吐を認め,通常の豚では,静脈内又は経口的にウイルスを投与し,30%又は15%の炭俄ガスを吸入させたもので下痢と嘔吐を認めた.一方Teschcnウイルス群と血清学的に関係のあるEl株では,その強い病原性から,これらの影響を認めることは出来なかった.

GASEOUS ENVIRONMENT AND GROWTH OF MICROAEROPHILIC VIBRIOS.

Fletcher, R. D. (University of Connecticut, Storrs), and W. N. Plastridge. Gaseous environment and growth of microaerophilic vibrios. J. Bacteriol. 87:352-355. 1964.-Strains of microaerophilic vibrios from cattle, chickens, man, and sheep were placed in four groups on the basis of catalase and H(2)S production and glycine tolerance. By these tests group I was + - -, group II was + - +, group III was + + +, and group IV was - + +. On yeast extract-agar, the optimal oxygen level was 2.5% for group I, and 5.0% for the other three groups; the optimal carbon dioxide level was 10% for all four groups; the group I strains from man and sheep and the group II strains differed from the group I strains from cattle, by tolerating higher levels of both oxygen and carbon dioxide. On a chemically defined medium, the optimal oxygen level was 1.0%, and the optimal carbon dioxide level was 10% for groups I and II; the group II strains were more sensitive to high levels of carbon dioxide than were group I strains from cattle.

THE IRRIGATION OF THE GILLS IN FISHES: II. EFFICIENCY OF OXYGEN UPTAKE IN RELATION TO RESPIRATORY FLOW ACTIVITY AND CONCENTRATIONS OF OXYGEN AND CARBON DIOXIDE

Respiratory volumes, percentage utilizations of oxygen, and rates of oxygen consumption were measured in non-swimming and swimming white suckers, brown bullheads, and carp under various ambient levels of oxygen and carbon dioxide. Up to 85% of the oxygen in the inspired water is removed by quietly breathing fish. Generally, high respiratory volumes are associated with low percentage utilizations of oxygen and vice versa. At high respiratory volumes carp remove about twice as much oxygen from the inspired water as do suckers and bullheads. Respiratory volumes are increased by as much as 30 times over the volume for quiet respiration by low levels of oxygen or high levels of carbon dioxide. Respiratory volumes of swimming fish are greater than those of non-swimming, rested fish in air-saturated water but they are not as high as those of non-swimming fish exposed to low ambient oxygen levels.The effects of moderate increases in ambient carbon dioxide on non-swimming fish may be temporary only. If the rise in the pCO2is slight to moderate, the percentage utilizations of oxygen at given respiratory volumes are at first depressed but may return, after 3 to 5 hours, to the levels they held before the pCO2was raised. Actively swimming fish respond to any increase in the pCO2by permanently increased breathing rates and decreased percentage utilizations of oxygen and rates of oxygen consumption.The number of respiratory units or lamellae per millimeter of gill filament in suckers, bullheads, and carp weighing 200 g are about 14, 10, and 20 respectively, but the total numbers and areas of lamellae are such that total gill areas are nearly identical among these three species.

Development of susceptibility to seizures in young animals. III. Brain water, electrolyte and acid-base metabolism.

SummaryIn newborn, 1-month-old and adult rats, susceptibility to maximal electro-shock seizures has been correlated with distribution of water and electrolyte concentrations and total carbon dioxide content of the cerebrum. Seizure susceptibility is greatest at one month of age. It is related inversely to the ratio of extracellular to cellular sodium and directly to the ratio of cellular and extracellular brain water. The relation to distribution of potassium is inconstant. The newborn guinea pig, an animal more mature than the rat at birth, corresponds more closely to the older and adult rat, both with regard to seizure susceptibility and brain water and electrolyte metabolism. Failure to induce convulsions in the newborn rat is associated with a high level of total carbon dioxide in the brain. Development of seizure susceptibility in older rats is related to a rise in brain carbonic anhydrase activity and to a reciprocal fall in total carbon dioxide content of the brain.

The use of artificial respiration in pulmonary emphysema accompanied by high carbon dioxide levels.

A syndrome resembling carbon dioxide narcosis, which may be precipitated by the administration of oxygen to patients with advanced emphysema, has attracted increasing attention in recent years, although few reports on this subject have appeared in the literature (1-7). A similar response to oxygen has been described by Marshall and Rosenfeld (8) in experimental animals anesthetized with barbiturates or morphine. Marshall and Rosenfeld's analysis provides a basis for understanding the phenomenon in man; in the presence of an increased level of carbon dioxide in the alveolar air and arterial blood, the respiratory center becomes adjusted to the high carbon dioxide pressure, so that carbon dioxide no longer dominates the chemical control of respiration. Such a loss of sensitivity to carbon dioxide in patients with advanced emphysema was demonstrated in 1920 by Scott (9). In the presence of high levels of carbon dioxide and diminished responsiveness of the respiratory center, the principal stimulus to breathing arises from the effects of hypoxia on the carotid body and aortic chemoreceptors. When the stimulus is removed by relief of the hypoxia through oxygen administration, the driving mechanism is weakened or absent, and pulmonary ventilation falls.

Influence of Controlled-Atmosphere Storage on Respiration of McIntosh Apples

1. McIntosh apples respired approximately one-third as fast in controlled-atmosphere storage at 40⚬ F. as in ordinary cold storage at 32⚬ F. The residual effect of controlled-atmosphere storage on apples after their removal to high temperatures can be partially explained by a reduction in respiration rate following the storage treatment. The residual effect cannot be accounted for by persistence of a high carbon dioxide level in the tissues of the fruit. 2. McIntosh held in cold storage at 32⚬ F. evolved two and one-half to three times as much carbon dioxide during the same time period in storage as controlled-atmosphere fruit. The value and limitations of cumulative respiration curves for this type of study are indicated.