Peristaltic Contraction Waves Research Articles

Oesophageal motor responses to gastro-oesophageal reflux in healthy controls and reflux patients

Aims—To compare oesophageal motor responses to gastro-oesophageal reflux (GOR) in 16 healthy controls (group 1) and 25 reflux patients, 15 without (group 2) and 10 with (group 3) oesophagitis.Methods—All subjects...

A homolog of human transcription factor NF-X1 encoded by the Drosophila shuttle craft gene is required in the embryonic central nervous system.

NF-X1 is a novel cytokine-inducible transcription factor that has been implicated in the control of immune responses in humans, presumably by regulating expression of class II major histocompatibility genes. Here we report the cloning and genetic characterization of the first reported NF-X1 homolog, which is encoded by the Drosophila melanogaster shuttle craft (stc) gene. The deduced sequence of the fly and human proteins defines a new family of molecules distinguished by a novel cysteine-rich DNA-binding motif (consisting of seven copies of the consensus sequence Cx3Cx3LxCGx0-5HxCx3CHxGxCx2Cx7-9CxC). We have identified and begun a phenotypic characterization of mutations in the stc gene. stc mutants die at the end of embryogenesis, when they appear to be incapable of coordinating the typical peristaltic contraction waves normally required for embryos to hatch into feeding first instar larvae. Preliminary evidence indicates that the resulting lethality of this behavioral defect is accompanied by subtle morphological abnormalities in the central nervous system, where in wild-type embryos, STC protein is normally localized in the nuclei of repeated cell clusters within each neuromere and brain lobe. Thus, the NF-X1 homolog encoded by the Drosophila stc gene defines a new family of putative transcription factors and plays an essential role in the completion of embryonic development. This study presents the first in vivo genetic analysis of a member of this new protein family.

Topography of normal and high-amplitude esophageal peristalsis.

Topographic plots were created from esophageal manometric tracings in 12 asymptomatic volunteers and 10 symptomatic patients with high-amplitude peristaltic contraction waves (nutcracker esophagus) to identify segmental contraction differences between the two groups. Median waves at each centimeter of esophageal length were spatially interconnected using a computerized gridding and plotting system, and a characteristic peristaltic contraction from the proximal esophageal body through the lower sphincter was constructed for each subject. Contour plots in the volunteers revealed three amplitude troughs dividing the peristaltic contraction into four sequential segments: the skeletal muscle body, the proximal and distal segments of the smooth muscle body, and the lower sphincter region. In nutcracker-esophagus patients, only the first and third troughs could be identified, since augmented contraction in the distal smooth muscle segment blurred separation of the smooth muscle body segments. Volume measurements under the topographic plots showed no significant intergroup differences in contraction of the skeletal muscle region or lower sphincter but modest increase in contraction of the proximal smooth muscle segment [1.7 times normal, 95% confidence interval (CI) 1.2-2.0; P = 0.002 comparing 2 groups] and marked increase in the distal smooth muscle segment (2.7 times normal, 95% CI 2.0-3.3; P < 0.0001). These data indicate that normal peristalsis through the esophageal body and lower sphincter includes four separate contraction segments that can be distinguished with intraluminal manometry and the topographic analysis method. The nutcracker esophagus primarily affects the distal segment in the smooth muscle body.

Validation of a Non‐invasive Radioisotope Method of Imaging Ureteric Urine Transport

Measurement of ureteric function has hitherto involved the use of invasive techniques. A non-invasive, radioisotope method of imaging and displaying individual ureteric boluses has been described, a refinement of which is used in this department. Each "spindle" displayed using this technique theoretically represents an individual ureteric bolus of urine, but the technique has never been validated in the normal ureter in either the experimental model or man. A porcine model was set up to allow simultaneous measurement of ureteric bolus transmission using the radioisotope (compressed image) method and by the accepted techniques of electromyography (EMG) and urine drop counting. The timing of each urinary bolus, as recorded by the different modalities was then compared. The results from 11 studies showed a significant correlation between the radioisotope and EMG methods (mean r = 1.00, P = 0.0003). There was a constant relationship between the part of the radioisotopic image representing the rear end of the bolus and the EMG complex (mean time difference = 5.32 +/- 1.067s), thus defining that part of the image representing the peristaltic contraction wave. There was a variable relationship between the EMG and the part of the image representing the leading edge of the bolus (mean time difference = 13.36 +/- 5.23s), emphasising that bolus length is variable, being dependent on bolus volume. The radioisotope "spindle" concurs with EMG activity in the porcine ureter. The compressed image technique is thus validated as a non-invasive method of demonstrating ureteric urine transport.

Manometric patterns using esophageal body and lower sphincter characteristics

In order to determine the actual spectrum of abnormal esophageal motility, manometric patterns in 1013 consecutive tracings were established using a classification method that employs esophageal body and lower esophageal sphincter (LES) characteristics. Peristaltic performance and contraction wave parameters were measured in the esophageal body; basal pressure and relaxation were included for the LES. Nine hundred thirty (92%) of the tracings could be completely classified, and 33 different patterns were observed (915 occurring at a rate greater than 1%). Abnormalities were most common in contraction wave parameters (661 tracings, 65%), and least common in LES relaxation (105 tracings, 10%). Patterns most typical of achalasia and diffuse esophageal spasm were found in 6.4% and 5.0% of tracings, respectively. Statistical analysis of the patterns demonstrated that significant bidirectional predictive associations between categories were restricted to features representing pathology-based motor disorders (ie, achalasia and "scleroderma-esophagus"). This systematic classification method is capable of recognizing and cataloging common findings of motor dysfunction in the esophageal body and LES as well as uncommon patterns representing traditional motility disorders. Our findings provide reference data for clinical esophageal manometry.

Dynamics of the upper urinary tract: I. Peristaltic flow through a distensible tube of limited length

A theoretical analysis and numerical solutions are presented for viscosity-dominated flow through a uniform, highly distensible tube with a slit-shaped cross section undergoing peristalsis. At flow rates below an intrinsic upper limit to the peristaltic carrying capacity of the tube, provided that there is always at least one peristaltic contraction wave in the tube, two different types of steady peristaltic flow are possible, with well defined boluses separated by regions where the tube is nearly completely occluded (flow with isolated boluses and flow with boluses in contact). Above this limit two other non-steady types of flow are possible, in which the boluses are less well defined and the contraction waves are in general not completely occlusive (flow with leaky boluses and open-tube flow). In flow with isolated boluses, boluses in contact and leaky boluses, the upstream pressure is determined by the mechanical properties (active and passive) of the tube undergoing peristalsis. In open-tube flow it is primarily determined by the resistance of the outlet from the tube.

Influence of metenkephalin analogue on motor activity of the gastrointestinal tract

The effect of the metenkephalin analogue Hoe 825 on esophageal motility, fundic accommodation to distention, and migrating myoelectric complex was studied in 17 healthy volunteers. The metenkephalin analogue (40 μg i.v.) significantly increased the duration, amplitude, and propagation velocity of the postdeglutitive esophageal peristaltic contraction waves. It had no effect on the basal lower esophageal sphincter pressure but significantly decreased the completeness of the sphincteric relaxation from 85% ± 5% on placebo to 70% ± 7% (p < 0.01). The metenkephalin analogue (40 μg i.v.) significantly decreased the fundic accommodation to distention. In doses ranging from 20 to 60 μg i.v. it induced a premature phase III of the migrating motor complex that started ectopically in the duodenum (without a gastric component) and migrated distally at a significantly higher velocity than a spontaneous phase III. It is hypothesized that the metenkephalin analogue induces these effects via an inhibition of the inhibitory nervous system.

Dynamics of the upper urinary tract: II. The effect of variations of peristaltic frequency and bladder pressure on pyeloureteral pressure/flow relations

For pt. I see ibid., vol.32, no.7, p.813-22 (1987). The dynamics of pyeloureteral flow is described when there is no peristalsis and for peristalsis of high and intermediate frequencies, on the assumption that the ureter is uniform except in the mid-ureter and at the outlet. The possibility of upstream transmission of bladder pressure variations to the renal pelvis is considered. The overall behaviour depends on three principal variables, the maximum tube pressure in the contraction waves, the intrinsic peristaltic carrying capacity and the peristaltic frequency f, expressed in the form fT where T is the time for a peristaltic contraction wave to sweep through the ureter. At intermediate peristaltic frequencies (fT less than but comparable with one) oscillatory flow patterns can occur, in which periods of peristaltically driven flow alternate with extraperistaltic periods of flow through the open ureter. The kidney is better isolated from bladder pressure variations when the peristaltic frequency is high, but high peristaltic frequency can by itself lead to elevated renal pelvic pressure if the flow rate is high. Experimental observations in pigs are presented to support these conclusions.

Multipeaked esophageal peristaltic pressure waves in patients with diabetic neuropathy

We evaluated esophageal function in 14 consecutive insulin-dependent diabetic patients who had evidence of peripheral and autonomic neuropathy, but no esophageal symptoms. One to three contraction waves immediately followed a primary peristaltic contraction wave. The majority of these multipeaked pressure complexes consisted of two peaks. Multipeaked contractions were observed with all peristaltic waves in 12 of the 14 diabetic patients and with most of the peristaltic complexes in the remaining 2 patients. Multipeaked peristaltic waves were present in 1 of 6 diabetic patients without neuropathy, in 1 of 100 consecutive nondiabetic patients referred for suspected esophageal disease, and in 1 of 10 healthy volunteers. Double-peaked peristaltic pressure complexes in the nondiabetic control subjects differed from those present in the insulin-dependent patients by their low incidence and by a tendency to be limited to the distal esophagus. Pharmacologic responses to edrophonium and atropine suggested a possible increased cholinergic tone as the basis of the multipeaked peristaltic waves in diabetics with autonomic neuropathy.

Effect of Diuresis and Glucagon on Upper Urinary Tract Dynamics in the Dog

The effect of glucagon on upper urinary tract peristalsis during extreme diuresis was studied in an unsedated dog preparation. In all experiments glucagon inhibited the peristaltic contraction waves without affecting urine propulsion, suggesting that peristalsis, at least for short periods, is not necessary for effective urine transport during extreme diuresis.

The propagation of contractile waves from duodenum to jejunum.

1. The peristaltic contractions of the duodenum and the upper jejunum were measured simultaneously and continuously with extraluminal straingauge transducers in the unanaesthesized dog. 2. No independent peristaltic pacemaker in the duodenojejunal flexure region was found by correlating the measurements. 3. On the contrary, the jejunal rhythm was strongly coupled to that of the duodenum, apparently because of the conduction of a coordinating impulse, whose speed can also change. 4. It is concluded that peristaltic contraction waves run continuously from the duodenum to the upper jejunum without interruption.