Clinical and pH study characteristics in reflux patients with and without ineffective oesophageal motility (IEM)

Background

The aetiology and clinical impact of ineffective oesophageal motility (IEM) remain poorly understood, but the condition is thought to worsen supine gastro-oesophageal acid reflux (GERD).

Aims

In this retrospective cohort analysis of symptomatic patients with abnormal oesophageal acid exposure, we sought to determine any clinical or functional characteristics that would distinguish those with normal peristalsis from those with IEM, defined using the Chicago classification. We hypothesised that the impaired oesophageal clearance in IEM would be contributing to more severe degrees of pathological acid exposure, as well as clinical and endoscopic GERD severity.

Methods

Consecutive symptomatic patients with GERD underwent clinical, endoscopic and functional evaluation that included high-resolution impedance manometry (HRIM) and ambulatory pH monitoring performed ‘off’ acid suppressive therapy.

Results

Of the 114 patients with abnormal oesophageal acid exposure, 71 had normal oesophageal motility by HRIM and 43 were diagnosed with IEM (38% prevalence). Age, gender and symptom duration were similar between the two groups. Both groups had similar magnitude and frequency of symptoms, making a distinction clinically impossible. Endoscopically, the two groups had similar rates of erosive disease, hiatal hernia and Barrett's oesophagus. Ambulatory pH, proton pump inhibitor (PPI) dosage and PPI response rates were also similar. Nevertheless, patients with IEM had significantly more impairment of oesophageal clearance (mean 56.9±6.4) than those with normal motility (mean 32.4±5.0) (p<0.003).

Conclusions

Symptomatic patients with IEM exhibit significant impairment of oesophageal clearance but are otherwise clinically indistinguishable from those with normal oesophageal motility and have a similar prevalence of erosive disease and pathological acid exposure.

ESTIMATION OF THE NITRIC OXIDE FORMED FROM HYDROXYLAMINE BY NITROSOMONAS

1. Nitric oxide that was produced by reducing nitrite with an excess of acidified potassium iodide under nitrogen in Warburg respirometer flasks was rapidly absorbed by a solution of permanganate in sodium hydroxide held in the side arm. A small amount of nitrous oxide (or nitrogen) that was also produced was not absorbed. 2. By using a quantitative method for the recovery of nitrite from samples of the alkaline permanganate, it was found that the sum of the nitrite N formed and the residual nitrous oxide N was equivalent to the nitrite N used to generate the gases. These results showed that alkaline permanganate completely oxidized nitric oxide to nitrite. The method was suitable for determining 0.4-20 mumoles of nitric oxide. 3. The technique was used to determine the nitric oxide content of the nitrogenous gas that was produced anaerobically from hydroxylamine by an extract of the autotrophic nitrifying micro-organism Nitrosomonas in the presence of methylene blue as electron acceptor.

BRAIN MITOCHONDRIA. II. THE RELATIONSHIP OF BRAIN MITOCHONDRIA TO GLYCOLYSIS

A mitochondrial fraction prepared from calf brain cortex possessed negligible glycolytic activity in the absence of the enzymes of the high speed supernatant fraction. When mitochondria were added to a supernatant system supplemented with optimal amounts of crystalline hexokinase, a 20 per cent stimulation of glycolysis was observed. The supernatant fraction produced minimal amounts of lactate in the absence of exogenous hexokinase; the addition of mitochondria doubled the lactate production. The substitution of glycolytic intermediates for glucose as substrates as well as the addition of exogenous glycolytic enzymes to the supernatant fraction or supernatant fraction plus mitochondria indicated that the mitochondria contributed mainly hexokinase and phosphofructokinase. By direct assay of all of the enzymes of the glycolytic pathway, only hexokinase and phosphofructokinase were shown to be concentrated in the mitochondrial fraction. All other glycolytic enzymes were found to exhibit higher total and specific activities in the supernatant fraction.

DETERMINANTS OF INTRAMYOCARDIAL PRESSURE IN THE CAT

Determinants of intramyocardial pressure in the cat were investigated by means of a small latex tube inserted into the wall of the left ventricle. Maximal intramyocardial pressures were generally below carotid systolic pressures. Rhythmic variations in intramyocardial pressure occurred and were related to pulmonary ventilation. There was no evidence of efferent vagal activity on the left ventricle. Sympathetic stimulation increased and sympathetic blockade (with Pronethalol) decreased intramyocardial pressure. Intramyocardial pressure was increased by venous infusions and by constriction of the aorta.

GLYCOLIC ACID OXIDATION BY ESCHERICHIA COLI ADAPTED TO GLYCOLATE

Furuya, Akira (University of Illinois College of Medicine, Chicago) and James A. Hayashi. Glycolic acid oxidation by Escherichia coli adapted to glycolate. J. Bacteriol. 85:1124-1131. 1963.-A procedure is described for extraction and partial purification of glycolic acid oxidase from Escherichia coli adapted to grow on glycolate as the sole carbon source. Enzyme activity was assayed by oxygen uptake and by reduction of 2,6-dichlorophenol-indophenol. Glyoxylic acid was the product of glycolate oxidation by the enzyme. Enzyme activity, which diminishes rapidly on storage, shows a maximum at pH 6 to 7. We were unable to show any cofactor requirement. Compounds which inhibited glycolate oxidation and their order of inhibitory activity were: p-hydroxymercuribenzoate > sodium azide > iodoacetate and o-phenanthroline > ethylenediaminetetraacetic acid. Tests of enzyme specificity showed that the following compounds were oxidized, but at different rates: glycolate, d-lactate, l-lactate, dl-alpha-hydroxybutyrate, dl-malate, and dl-glycerate. Citrate, tartrate, and dl-beta-hydroxybutyrate were not oxidized. Potassium cyanide stimulated oxygen uptake when glycolate and lactate were oxidized. Whether the oxidations were due to different oxidases or to a single oxidase with a wide range of specificities was tested by observing the oxidation of glycolate, d-lactate, and l-lactate under various conditions. Ammonium sulfate fractionation of a crude extract did not change the relative ability to oxidize the three acids. However, the three oxidative capacities diminished at different rates during storage at 0 C for 6 days. The partially purified glycolic oxidase preparations were probably mixtures of several different oxidases.

GLUCOSE CATABOLISM BY BACILLUS POPILLIAE AND BACILLUS LENTIMORBUS

Pepper, Rollin E. (Michigan State University, East Lansing), and Ralph N. Costilow. Glucose catabolism by Bacillus popilliae and Bacillus lentimorbus. J. Bacteriol. 87:303-310. 1964.-Resting cells of Bacillus popilliae and B. lentimorbus catabolize glucose with the production of CO(2), lactic acid, acetic acid, glycerol, ethanol, and trace amounts of acetoin and acetaldehyde. The first three products are the major ones, and their ratios may be varied by controlling the availability of oxygen. Practically no lactic acid is produced when oxygen is not limiting, whereas it may comprise up to 80% of the total acid when oxygen is greatly limited. However, no glucose is catabolized by resting cells in the absence of molecular oxygen. Isotope and inhibitor studies and assays for key enzymes of the established metabolic routes all indicate that these organisms utilize both the Embden-Meyerhof and hexosemonophosphate pathways for glucose dissimilation. With a concentrated resting-cell suspension, the extent of participation of the latter route was estimated to be as high as 40% in an atmosphere of pure oxygen, and as low as 2% in air. Acetate was oxidized by only one of the cultures of B. popilliae tested, which is apparently a mutant. Cells of this strain from stationary phase cultures oxidized acetate at pH 7.0 or higher, but not at pH 6.0; however, they oxidized succinate, fumarate, and malate more rapidly at pH 6.0 than at 7.0. The oxidation of tricarboxylic acid cycle intermediates, the presence of condensing enzyme in extracts of cells capable of oxidizing acetate, and the complete inhibition of acetate oxidation by arsenite and partial inhibition by malonate all indicate that terminal oxidation of acetate by this strain of B. popilliae is via the tricarboxylic acid cycle.

ELECTRON TRANSPORT SYSTEM IN VEGETATIVE CELLS AND MICROCYSTS OF MYXOCOCCUS XANTHUS

Dworkin, Martin (University of Minnesota, Minneapolis), and Donald J. Niederpruem. Electron transport system in vegetative cells and microcysts of Myxococcus xanthus. J. Bacteriol. 87:316-322. 1964.-Respiration by intact cells of the fruiting myxobacterium Myxococcus xanthus is cyanide-sensitive and can be demonstrated in the vegetative cells but not in the microcysts. Cell-free particles from both vegetative cells and microcysts have cyanide-sensitive reduced nicotinamide adenine dinucleotide (NADH) oxidase, diaphorase, NADH cytochrome c reductase, and cytochrome oxidase activities. While the vegetative cell specific activities for NADH oxidase and diaphorase are slightly higher than those for the microcysts, the microcysts have ten times the cytochrome c reductase and cytochrome oxidase activities of the vegetative cells. Furthermore, the respiration of the microcyst particles is considerably less cyanide-sensitive than is that of the vegetative-cell particles. Difference spectra of the cell-free particles of vegetative cells and microcysts are qualitatively identical, showing the presence of b- and c-type cytochrome and flavoprotein. The a-type pigments are clearly present in the extracts of the vegetative cells and are suggested by the spectrum of the microcyst particles. The cytochrome oxidase activity of both extracts is consistent with the presence of a-type pigments in both. The spectra of the carbon monoxide-binding pigments were determined and, by this parameter, qualitative differences appear between the vegetative cells and the microcysts.

FUNCTIONAL CARDIAC DETERIORATION DURING DEVELOPMENT OF HEMORRHAGIC CIRCULATORY DEFICIENCY

A massive infusion test has been devised to evaluate the functional capacity of the heart.

In five dogs extensive surgical procedures followed by episodes of arterial hypotension at 30 mm Hg and lasting 90 minutes caused severe cardiac incapacity, which was demonstrated by failure of rate of cardiac work to increase throughout the infusion together with a large rise in left atrial pressure. This incapacity was not evident in tests made immediately after the hypotensive episode. The damage became more and more severe in tests performed 90 and 150 minutes after the end of the hypotension even though mean arterial pressure was maintained at 100 mm Hg. Operated control dogs did not show cardiac deterioration in tests timed as above. The rate of cardiac work continued to increase throughout the infusion with a relatively small rise of left atrial pressure.

In a series of five dogs, flow to the coronary arteries and to those supplying the head and forelimbs was maintained by normal blood pressure while the rest of the animal was made hypotensive for 90 minutes. The arterial pressure in the whole animal was then returned to an average level of 100 mm Hg. Tests made at intervals after the hypotension showed equivocal evidence of cardiac deterioration.

In another series of four dogs, prepared as above, the partial hypotension lasted 150 minutes before the arterial pressure was returned to normal. Tests at intervals after hypotension showed cardiac damage in all the animals and severe damage in three. Evidence is presented indicating that the peripheral vascular bed had deteriorated functionally as a result of 150 minutes of partial hypotension.

PATTERNS OF OXIDATIVE ASSIMILATION IN STRAINS OF ACETOBACTER AND AZOTOBACTER

Tomlinson, Geraldine A. (The University of British Columbia, Vancouver, B.C., Canada), and J. J. R. Campbell. Patterns of oxidative assimilation in strains of Acetobacter and Azotobacter. J. Bacteriol. 86:1165-1172. 1963.-Oxidative assimilation of glucose-U-C(14) was studied with washed-cell suspensions of Acetobacter aceti, A. xylinum, Azotobacter vinelandii, and A. agilis. The suggestion that oxidative assimilation is largely the incorporation of endogenously produced ammonia is tenable. A. aceti did not exhibit oxidative assimilation and it did not incorporate ammonia in the presence of glucose, alpha-ketoglutarate, or pyruvate. A. xylinum, A. vinelandii, and A. agilis incorporated C(14) into the nitrogenous fractions of the cell. The level of assimilation into A. xylinum was low due to the accumulation of extracellular cellulose, and the level of assimilation into the Azotobacter was low presumably because of the requirement of energy for nitrogen fixation. The Azotobacter were characterized by the presence of a high level of radioactivity in the cold trichloroacetic acid-soluble pool. None of the organisms accumulated compounds in the supernatant fluid that might be considered pacemakers in glucose oxidation, and this could be a contributing factor in the low level of assimilation.

OBLIGATELY PSYCHROPHILIC YEASTS FROM THE POLAR REGIONS

Sixty-seven pure cultures of psychrophilic bacteria and yeasts were isolated from polar ice, snow, soil, and other materials. Low temperatures were maintained during all phases of the isolation procedure to avoid possible destruction of obligate psychrophiles. Four of the cultures, all yeasts, proved to be obligate psychrophiles. Three are species of Candida and one of Torulopsis. They grew in the range of 0 °C to 20 °C and the optimum growth temperature was 15 °C. They died rapidly when exposed to temperatures of 30 °C or 40 °C.The rate of fermentation of glucose by psychrophilic Candida sp. P16 was higher than that of mesophilic Saccharomyces cerevisiae at temperatures below 25 °C. At and above 25 °C, this rate relationship was reversed and at 35 °C all fermentative activity of the psychrophilic yeast was destroyed while that of the mesophile was maximal. Oxidative activity of Candida sp. P16 was much less sensitive to 35 °C, which suggests that fermentation and oxidation proceed by different pathways.The extent of occurrence of obligately psychrophilic microorganisms in nature is discussed.

UPTAKE OF FREE PLASMA AMINO ACIDS BY THE LACTATING COW'S UDDER AND AMINO ACID COMPOSITION OF UDDER LYMPH

1. Total alpha-amino N and the amounts of 24 ninhydrin-positive substances were determined in several samples of plasma and lymph from the cow's udder. The arteriovenous differences of these substances across the mammary glands were measured in several experiments performed on lactating cows and in one experiment on a ;dry' cow. Udder lymph obtained from live lactating cows by a lymph fistula and taken after killing lactating cows was analysed. 2. The concentrations of the individual free amino acids in udder lymph obtained from the live cow were similar to those found in cow's plasma. The concentrations of many amino acids in udder lymph taken immediately after death were two- to four-fold higher than those of the corresponding amino acids in udder lymph obtained from the live cow. 3. Most amino acids of the blood showed a considerable decrease in concentration by passage across the lactating mammary gland. Ornithine, a non-casein amino acid, showed arteriovenous differences of up to 60% of the arterial plasma concentration. No substantial amino acid uptake by the udder could be demonstrated in the experiment on the non-lactating cow. 4. The arteriovenous differences obtained for arginine, glutamine, isoleucine, leucine, lysine, valine, threonine and histidine were probably large enough to provide all the respective amino acid residues in milk protein. 5. The uptake of aspartic acid, asparagine, glutamic acid, serine and proline by the lactating cow's udder was not sufficient to account for all these respective amino acid residues found in milk protein.

AN ISOTHERMAL SYSTEM FOR MANOMETRIC MEASUREMENT OF CHANGES OF VOLUME

The volume of gas to be measured is displaced into a reservoir which is so constructed that its contents undergo nearly perfect isothermal compression, raising the pressure by up to 1 mm Hg relative to the pressure in an identical compensating reservoir. The conditions of compression ensure a stable calibration over a wide range of rates of gas displacement, and the use of a compensating reservoir makes the system quite independent of fluctuations in barometric pressure, and largely independent of fluctuations in ambient temperature.

volume recorder; air displacement recorder; barometric measurement of volume

Submitted on December 9, 1963