STUDIES IN THE PHYSIOLOGY OF SPERMATOZOA

Extract: Acid-base balance in blood and hydrogen ion, phosphorus concentrations, and acid-base excretion in urine were measured in 10 infants with respiratory distress syndrome (RDS), in 8 control full term infants, and in 7 control premature infants on days 1, 2, and 3 of life. Infants with RDS were acidemic in comparison with full term and premature control infants. Hydrogen ion concentrations in urine were similar for premature control subjects and acidemic infants with RDS but lower in comparison with those of full term control infants. The inability of infants with RDS, in the face of acidemia, to create an appreciable urine to plasma hydrogen ion concentration gradient provided evidence for a renal tubular deficiency in hydrogen ion secretion. Phosphate levels in urine and, as a result, titratable acid were usually low in the three groups of infants. Relative phosphaturia did occur in some infants with RDS, but, because of the deficiency in hydrogen ion secretion, urinary phosphate was often not utilized as titratable acid. At high urinary concentrations of hydrogen ion (above 400 μmEq/liter), control premature infants and acidemic infants with RDS excreted urine having lower ammonium concentration than that found in control full term infants. The inability of infants with RDS with acidemia to excrete ammonium when hydrogen ion concentrations in urine were high was evidence of a renal tubular deficiency in ammonia production. Infants with RDS differed from control premature infants by having high hydrogen ion and bicarbonate concentrations in blood in relation to higher blood PCO2 values. In addition, at low hydrogen ion concentrations in urine, infants with RDS excreted urine that contained higher concentrations of bicarbonate than that found in control premature infants. Because infants with RDS did not excrete ammonium, they could not compensate for the increased acid load and bicarbonate excretion associated with respiratory acidemia. In addition, they could not compensate for the low titratable acid, which resulted from decreased excretion of phosphate, characteristic of the newborn period. Infants with RDS did not respond to acidemia by increasing net acid excretion in urine beyond that excreted by control infants. Indeed, some infants with RDS inappropriately excreted base, thereby aggravating their already existing acidemia. Speculation: Low gestational and postnatal age is the likely etiologic factor responsible for the decreased capacity for urinary acid excretion seen in infants with RDS. The apparent improvement in renal tubula hydrogen ion secretion with increasing gestational age may be associated with maturation of an enzyme system such as carbonic anhydrase. Likewise, the apparent improvement in renal tubular ammonia production with increasing gestational age may occur in relation to maturation of an enzyme system such as glutaminase.

Characteristics of the large-scale circulation during episodes with high and low concentrations of carbon dioxide and air pollutants at an arctic monitoring site in winter

ASSIMILATION AND RESPIRATION OF EXCISED LEAVES AT HIGH CONCENTRATIONS OF CARBON DIOXIDE

Lowering the current density as a strategy to improve biogas upgrading and economic feasibility of a hybrid electrocoagulation – up-flow anaerobic sludge blanket reactor

New study on the correlation between carbon dioxide concentration in the environment and radon monitor devices

Impacts of elevated water carbon dioxide partial pressure at two temperatures on Atlantic salmon ( Salmo salar L.) parr growth and haematology

1. The optimum range of hydrogen ion concentration for both Hydra viridissima and Pelmatohydra oligactis lies within the range pH 7.8 and 8.0.2. Polyps allowed to develop pronounced dedifferentiation and resorption in a high hydrogen ion concentration (low pH) were induced to completely restore their lost parts when the medium was altered to be within the optimum range of pH.3. Hydras carried within the optimum range of pH were subjected to periods of inanition as great as twenty five days without showing any external evidence of dedifferentiation and resorption at the end of this period.4. Histological preparation of polyps, kept for long periods without food at the optimum hydrogen ion concentration, show slight evidence histologically of dedifferentiation and resorption at a critical period. This critical period appears somewhere between ten and seventeen days after inanition within the optimum range of pH. Such microscopic dedifferentiation and resorption are not progressive; for after this critical period has passed no further histological evidence of dedifferentiation and resorption has been observed.(b) This microscopic dedifferentiation and resorption usually appear at the tips of the tentacles; but in one case we have seen it involve the basal third of the polyp and not the tentacles.5. Hydras subjected to long periods of inanition within the optimum range of pH accept food readily. There is, therefore, no evidence of depression given by these polyps.6. Dedifferentiation and resorption are induced rather by unfavorable hydrogen ion concentration than by inanition.

BackgroundSivelestat, a neutrophil elastase inhibitor, was previously approved in Japan for the treatment of acute lung injury associated with systemic inflammatory response syndrome. However, sivelestat produced inconsistent therapeutic benefits. This study aimed to identify factors predicting the therapeutic effects of sivelestat.MethodsWe enrolled 53 mechanically ventilated patients who received sivelestat. The patients were classified as effective (n = 28) if they were weaned from the ventilator within 28 days, or as ineffective groups (n = 25). Patient characteristics were compared between these groups and multivariate logistic regression analysis was used to identify predictive factors. A validation study was then conducted in sivelestat-free patients.ResultsA high red blood cell count and low hydrogen ion concentration were significantly associated with a higher ventilator weaning rate in patients receiving sivelestat. The validation study revealed that the hydrogen ion concentration value also significantly associated with ventilator weaning in patients who did not receive sivelestat.ConclusionsAlthough hydrogen ion concentration was inversely associated with the ventilator weaning rate, it did not predict sivelestat efficacy. This study indicated that acute lung injury patients with a high red blood cell count would derive the most benefit from sivelestat administration.

ABSTRACTBackgroundIngestible wireless motility capsules enable locoregional quantification of luminal pH and concentrations of hydrogen and carbon dioxide in the human colon.AimTo evaluate these measures in the colon of healthy adults.MethodsGas‐sensing and pH‐sensing wireless motility capsules were ingested tandemly and repeatedly over time. Measurements were analysed and compared in proximal and distal segments of the colon.ResultsIn paired datasets from 37 participants, colonic pH rose from a median 6.3 (IQR 5.8–6.9) proximally to 7.0 (6.6–7.2) distally (p < 0.001). Concentrations of carbon dioxide rose in nearly all participants from 12.7 (9.1–18.6) proximally to 18.8 (11.9–28.1) %.h/h distally (p < 0.001) with a positive correlation between proximal and distal colon (r = 0.76; p < 0.001). Hydrogen concentrations showed widely varied proximal‐to‐distal gradients with an increase in 69% of participants, but no correlation between proximal and distal colon measures. No significant correlations between colonic pH, hydrogen concentrations, and carbon dioxide concentrations were observed. Comparison of hydrogen and carbon dioxide concentrations between tandem gas‐sensing capsules by Bland–Altman analysis (n = 24) showed minimal (< 1.2%) bias for both measures, and gas metrics on repeat ingestion were similar (n = 20). However, there was greater variance in the distal colon.ConclusionsBoth wireless motility capsules evaluate different yet complementary aspects of colonic fermentation. Carbon dioxide concentrations that most likely reflect overall microbial metabolic activity were consistently greater distally, while proximal‐to‐distal gradients in hydrogen concentrations varied, likely due to inter‐subject variations in dietary carbohydrate and/or methanogenesis. Luminal pH poorly reflects carbohydrate fermentation in the distal colon.Trial RegistrationACTRN12619001219178 and ACTRN12622000422729

On the physiological action of carbon dioxide on cortex and hypothalamus

1. Crayfishes sense the increase in carbon dioxide and acetic and hydrochloric acids in a gradient.2. Both propinquus and virilis are intoxicated by carbon dioxide; virilis is also intoxicated by acetic acid but to a lesser degree.3. The four species are susceptible to high concentrations of carbon dioxide and when subjected to high concentrations die in the following order, virilis, propinquus, diogenes and immunis.4. Propinquus reacts negatively to the higher concentrations of carbon dioxide in a gradient, but when the total amount of acid present is large, the negative reaction may be interfered with by the direct detrimental effect of the acid.5. Virilis reacts less definitely to the higher concentrations of carbon dioxide in a gradient than does propinquus. This is true whether the total concentration of the acid is large or small.6. Both diogenes and immunis react more or less irregular to carbon dioxide due possibly to the lesser sensitiveness of these two species to this acid.7. Both propinquus and virilis react negatively to the higher concentrations of acetic acid in gradients of this acid; propinquus reacts definitely in the presence of both high and low total concentrations; virilis reacts definitely to low total concentrations, but not so definitely to high total concentrations; diogenes reacts irregular and less intense than the first two species while immunis reacts more definitely but with low intensity.8. All four species react more strongly to hydrochloric acid than acetic acid and more strongly to acetic acid than carbon dioxide.9. The intensity of avoiding reactions of all species to all acids tested as is shown by turnings only are in the following order; propinquus, virilis, immunis and diogenes.10. The intensity of avoiding reactions of all four species varies directly as the total concentrations of the acids, and probably directly as the hydrogen ion concentration.11. Rapid modification of behavior is shown by all four species. This modification may be due to the increased sensitiveness on the part of the animals, the increased sensitiveness being the result of higher ion concentration in the animal's blood.12. The specific reactions of the crayfishes in gradients of carbon dioxide may be correlated with their habitats.

1. The effect of acidification of the medium on the rate of oxygen consumption of aquatic organisms was studied.2. The acids used were: hydrochloric, nitric, sulphuric, carbonic, butyric, acetic, citric, and tartaric. They were added to water to produce acidities ranging from pH 7.5 to 5.0, at intervals of 0.5 pH.3. Planaria dorotocephala was the chief animal used as material. Some tests with hydrochloric acid were also made using starfish and nudibranchs.4. The acidification of natural waters, either salt or fresh, (pH 8.0), by any of the acids used except butyric causes a decrease in the rate of oxygen consumption at all acidities greater than pH 7.0. The majority of acids also cause depression between 7.8 and 7.0 but in the case of acetic acid and more doubtfully carbonic, there was some tendency towards a slight acceleration of the rate of oxygen consumption at these lower concentrations.5. The decrease in the rate of oxygen consumption due to acids is completely and promptly reversible, as long as th...

Beneficial effects of alkalotic reperfusion following ischemic cardiac arrest

Solvent extraction of rare earths from nitrate leach liquor of apatite using mixtures of tributyl phosphate (TBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) was studied. The effects of nitrate and hydrogen ion concentration of the aqueous phase as well as the composition and concentration of extractants in the organic phase on the extraction behavior of lanthanum, cerium, neodymium, and yttrium were investigated. The distribution ratio of REEs increases by increasing the nitrate concentration in aqueous phase and concentration of extractants in organic phase, but the hydrogen ion concentration in aqueous phase has a decreasing effect. Yttrium as a heavy rare earth is more sensitive to these parameters than light rare earth elements. Although the composition of organic phase has a minor effect on the extraction of light rare earths, the percent of extraction of yttrium decreases dramatically by increasing the TBP content of organic phase. Mixtures of TBP and D2EHPA can show either synergism or antagonism extraction depending on the concentration and composition of extractants in organic phase. The best condition for separating rare earth elements in groups of heavy and light REEs can be achieved at high nitrate concentration, low H+ concentration, and high concentration of D2EHPA in organic phase. Separation of Ce and La by TBP and D2EHPA is practically impossible in the studied conditions; however, low nitrate concentration and high hydrogen ion concentration in aqueous phase and low concentration of extractants in organic phase favor the separation of Nd from other light rare earth elements.

Morphological changes occurring in cells of the mouse testis treated in hydrogen ion concentrations from pH 3.0 to 7.5 have been studied with the phase contrast microscope and in fixed-stained preparations. Living cells were prepared by techniques involving use of pressure and without pressure. The pressure technique was more advantageous for studying living cells. Many cells undergoing spermatogenesis produced pseudopodia which moved and grew in all media except that adjusted to pH 3.0. Blebs and bubbles occurred on cells treated at pH 4.0 to 6.0. Granulation of nuclei, which became more pronounced in solutions of greater acidity, was also observed. Cells at strongly acidic hydrogen ion concentrations clumped together and the membranes dissolved, leaving only clumps of chromosomes intact. Extreme shrinkage of cells occurred at pH 3.0. Pseudopodia, bubbles, or blebs were not observed in fixed-stained preparations, but dissolution of cells with subsequent freeing of chromosomes occurred at strongly acidic pH values. Granular droplets resembling secretory products were observed when cells were treated at high hydrogen ion concentrations.