Search PubMed⌕ Search

Biomedical subjects

H Gregersen

Publications and source records attributed to H Gregersen.

At least 91 records · Page 5Linked to original sources
PubMed1991

Versatile software system for analysis of gastrointestinal pressure recordings.

A software package, MotAn, has been developed for off-line analysis of gastrointestinal pressure recordings. The program has been implemented in the Modula-2 language for use on IBM personal computers. The program includes capabilities for manual or automatic detection of contractions, calculation of frequency and intercontractile intervals, area of contractions, motility index, concordance and cross-correlation analysis for detection of artifact and for propagation analysis. The program has been applied on pressure recordings from the stomach and duodenum as well as on the rectum and the urinary bladder. Besides the basic part of the program, it is possible for the experienced programmer to add new blocks of object code for development of special analysis procedures.

Computer Graphics↗
PubMed1991

Effect of vasoactive intestinal peptide on duodenal motility in the isolated perfused porcine pancreaticoduodenal block.

The peptidergic regulation of duodenal motility has not been clarified in detail. The aim of the present study was to investigate the effect of vasoactive intestinal polypeptide (VIP) on duodenal motility in the isolated perfused porcine pancreaticoduodenal block. VIP was administered arterially at 10(-7) M and motility was measured by means of the perfused side-hole technique using an intraluminal catheter. It was found that spontaneous duodenal motility was intense at the beginning of each experiment. However, the spontaneous motility diminished by time to cease after 45-90 min. VIP inhibited the duodenal motility. Thus, the frequency of duodenal contraction was decreased from 11 (8-16) to 3 (0-10) contractions per minute by VIP (p less than 0.01) and VIP also decreased the arterial perfusion pressure from 7.5 (3.5-23.2) to 5.8 (2.6-17.3) kPa (p less than 0.01). Since the same inhibitory effect has previously been demonstrated after alpha 2-adrenoceptor activation, we also examined whether alpha 1- and alpha 2-adrenoceptor agonism stimulated the release of VIP from this preparation. We then found that alpha 1-adrenoceptor agonism (phenylephrine or noradrenaline plus idazoxan) given intra-arterially stimulated VIP release (p less than 0.01). In contrast, alpha 2-adrenoceptor agonism (UK-14,304 or noradrenaline plus prazosin) had no effect. Therefore, we conclude that VIP inhibits duodenal motility in the pig but that this effect does not mediate the sympathetically induced inhibition of motility.

Animals↗
PubMed1991

Elastic properties of the isolated perfused porcine duodenum.

The aim was to investigate elastic wall properties of the isolated perfused porcine duodenum using manometry and impedance planimetry. Distension of an intraluminal balloon with definite pressure steps of 0.5, 1.0, 2.0, 3.0 and 5.0 kPa was done with simultaneous recording of balloon pressure and balloon cross-sectional area (Bcsa). Wall thickness of the relaxed intestine was estimated from measurement of tissue density. The elastic wall parameters were calculated from these measurements. Balloon inflation elicited a phase of rapid Bcsa increase followed by an accommodation phase of slow Bcsa increase. At steady state, the circumferential and the radial wall stress increased as linear functions of the applied balloon pressure, while the circumferential and the radial wall strain increased nonlinearly. The incremental elastic moduli increased exponentially. Our model allows the study of passive biomechanical wall properties of the intact duodenum. The duodenal wall showed qualitatively and also quantitatively an elastic nature.

Animals↗
PubMed1991

Measurement of anal cross-sectional area and pressure during anal distension in healthy volunteers.

A probe for simultaneous measurement of cross-sectional area and pressure was used to elucidate biomechanical wall properties during anal distension. Measurements in distal sphincter regions demonstrated a high resistance to stretch and a large hysteresis compared to proximal sphincter regions. Resistance to stretch decreased during anal distension indicating an active relaxation mechanism at all recording levels. The zone with high resistance to stretch was located more distal than the high-pressure zone measured by anal-pressure profilometry. In conclusion, biomechanical wall properties of the anal canal cannot be described by classic viscoelastic theories but rather by a loss of sphincter tone caused by reflex mechanism during anal distension.

Adult↗
PubMed1991

Radial analysis of duodenal motility recordings in humans.

To analyze radial variations in pressure recordings from the human duodenum, we used a catheter with six radially placed side holes with identical dynamic characteristics. Twenty-one hours of fasting pressure recordings were obtained in six volunteers. Computer-based cross-correlation analysis, event detection and counting, amplitude analysis, and concordance analysis were used for comparing the signals of the individual channels. Both the cross-correlation analysis and the counting of events showed radial asymmetry of contractile activity. This asymmetry was not related to any individual channel. The maximum difference between the individual channels was constantly between diametrically opposite spaced channels. The asymmetry was most pronounced during phase-I-like and phase-II-like activity of the migrating motility complex, whereas a much higher degree of cross-correlation and concordance was shown during phase-III-like activity. The results indicate that a greater in-depth analysis of pressure recordings from the small intestine--such as identification of individual events and differentiation between contractions and artefacts--requires that the recordings as a minimum comprise two diametrically placed side holes at each measurement level.

Adolescent↗
PubMed1990

[The clientele of physiotherapists in private practice].

The aim of the study was to describe sociomedical characteristics of physiotherapy patients. A material of 466 patients answered questions about personal and social data and their disease. Women were significantly more frequent in the material than men (p less than 0.001). The following groups were underrepresented compared to the background population calculated by X2: 1) boys 0-9 years, 2) girls 0-19 years, 3) women more than 80 years old, 4) officials, 5) unskilled workers and 6) unemployed. The following groups were overrepresented: 1) women 30-39 years, 2) women 60-79 years, 3) pensioners and persons receiving public assistance and 4) students. More than half of the symptoms were located to the head-neck or back-thorax-loin. The cause was most often primarily somatic (46%), while 25% had an occupational genesis.

Adolescent↗
PubMed1990

Variations in duodenal cross-sectional area during the interdigestive migrating motility complex.

A probe for measurement of intestinal cross-sectional area (CA) was used to elucidate variations of human gut CA during the interdigestive migrating motility complex (MMC). A balloon was inflated by saline at a pressure of 1 kPa, and variations of balloon CA (BCSA) were measured by means of the field-gradient principle. Duodenal phasic activity was measured by perfused side holes proximal to, distal to, and inside the balloon. In vitro characterization of probe performance showed that static measurement of BCSA was very accurate regardless of the configuration of the balloon. However, during dynamic measurements, BCSA was valid only for slow variations in BCSA due to resistance in the evacuation and inflation system. Eight duodenal MMCs were recorded. BCSA increased consistently from the start of phase I to the end of phase II from 72 (45-100) to 136 (87-154) mm2. During late phase II, a large BCSA increase was recorded. A positive correlation between the phasic activity level in phases I and II of MMC and maximal BCSA in duodenum was demonstrated (proximal P less than 0.01; distal P less than 0.05). BCSA during phase III was small but could not be estimated accurately because steady-state conditions were not obtained. The large BCSA in late phase II suggests a relaxation of the duodenal wall secondary to a decrease in smooth muscle tone. The results add evidence to previous findings of a low-resistance or large-capacitance situation in late phase II, observed as a large pancreaticobiliary excretion into the duodenum and an increased flow of duodenal contents.

Adult↗
PubMed1990

Galanin: distribution and effect on contractile activity and release of vasoactive intestinal polypeptide from the isolated perfused porcine ileum.

In the pig ileum galanin (GAL)-like immunoreactivity was identified in nerve cell bodies of the submucous plexus and in nerve fibers of the circular and longitudinal muscle layer. Infusion of 5.10(-10)-10(-8) M of GAL into the arterial line of the isolated perfused porcine ileum decreased the frequency of spontaneous phasic contractions in a dose-dependent manner. The frequency of phasic contractions during maximal inhibition by GAL 10(-8) M was 13 +/- 4% (mean +/- SE) of basal frequency (p less than 0.05). The recovery from inhibition by GAL 10(-8) M lasted 16 +/- 1 min. Tonic contractions were not observed in this experimental set-up, neither by standard perfused catheter manometry nor by measurement of cross-sectional area of an intraluminally located balloon. Infusion of GAL 10(-8) M decreased the venous release of vasoactive intestinal polypeptide to 80 +/- 8% of basal release (p less than 0.05). It is concluded that GAL may participate in the regulation of small intestinal motility in the pig.

Animals↗
PubMed1989

[Factors of significance for short or prolonged duration of physiotherapeutic treatment from private practicing physiotherapists].

The aim of the study was to determine factors of importance for the duration of treatment of physiotherapy patients. A material of 363 patients answered questions about personal and social data and their disease. The following was related to prolonged treatment (greater than 47 days): 1) young, unmarried students. There was twice as many boys as girls. 2) Patients with psychosomatic disease. The ratio between men and women was 1, and the main symptom was headache. 3) Patients with generalized disease. This study did not reveal whether prolonged treatment is due to an ineffective treatment or whether other factors are of importance. However, we doubt the effect of physiotherapy in patients with psychosomatic disease.

Adolescent↗
PubMed1989

The effect of a new selective alpha 2-adrenoreceptor antagonist, idazoxan, and the agonist, clonidine, on fasting antroduodenal motility in healthy volunteers.

Studies were carried out on 16 healthy male volunteers to investigate whether intravenous administration of the alpha 2-adrenoreceptor antagonist, idazoxan, could affect fasting antroduodenal motility with and without administration of the agonist, clonidine. Contractile activity was recorded using an oral tube with perfused side holes positioned in the stomach and duodenum. Clonidine decreased antral contractile activity, an effect that idazoxan did not restore. Idazoxan alone did not affect antral motility. In the duodenum, clonidine decreased the number of contractions significantly and idazoxan restored them. Idazoxan alone did not increase duodenal motility but clonidine induced phase-III activity within the first 15 min after administration. The observations indicate that regulation of antroduodenal motility is influenced by alpha 2-adrenoreceptor drugs. Idazoxan may have potential as a motility restoring drug, for example, in postoperative ileus.

Adolescent↗
PubMed1989

Spontaneous anorectal pressure activity. Evidence of internal anal sphincter contractions in response to rectal pressure waves.

To characterize spontaneous anorectal pressure activity and a possible relation between the activity in the rectum and the anal canal, 11 healthy female volunteers were investigated. Resting activities were obtained during 1-h recordings with a multi-channel perfused catheter measuring the pressure 1, 2, 3, 7, and 8 cm from the anal verge. In five subjects sequences of rhythmic rectal pressure waves with amplitudes exceeding the maximal anal resting pressure coincided with a similar internal anal sphincter activity, preventing rectal pressure from exceeding the anal pressure at any point. The mean frequency was 5 x min-1 (range, 3-6 x min-1). This may well be a reflex mechanism by which the internal anal sphincter prevents incontinence in the resting state. Low-frequency pressure waves, not previously described, were detected in four women. These pressure waves were attributed to the internal anal sphincter and were named ultra-slow waves type II. The mean frequency and amplitude were 0.16 x min-1 (range, 0.15-0.17 x min-1) and 24 cm H2O (range, 11-41 cm H2O), respectively. The function of these pressure waves is unknown.

Adult↗
PubMed1989

Computer analysis of manometric recordings. A study of overnight rectal activity in normal children.

To read and analyze manometric tracings from selected biological systems, a computer program was produced using low cost personal computer hardware. The program contains facilities for automatic scoring of contractions, intercontractile intervals (modality) and frequency analysis. This report concerns analysis of two overnight rectal motility recordings in 11 normal teenagers. After A/D conversion of data the developed software offers a set of options i.e. automatized scoring of contraction, detection of intervals between contractions and analytical tools such as histographic presentation of data, and presentation in the time domain. The A/D conversion time and computer analysis time for an 8 hour recording was 15 and 13 minutes, respectively. The analysis of frequency distribution overnight showed for the material as a whole 63% of no activity, 33% of 0-2 contractions x min-1 and 4% of more than 2 contractions x min-1. Modality analysis showed a peak between 15 and 25 seconds. Approximately 30% of the tracings showed accumulated intervals, which were multiples of the peak. No significant correlation was found between the first and second night of observation regarding the number of contractions and maximum frequency overnight. Significant correlation was found for the number of periods with high frequency activity between the two nights (p less than 0.05). Long-term pressure activity can be analyzed using the presented computer-aided method, providing a rapid and objective measurement of classical parameters and access to more in-depth analysis. This actual study of normal overnight rectal activity showed a large inter- and intra-individual variation.

Adolescent↗
PubMed1988

The four-electrode impedance technique: a method for investigation of compliance in luminal organs.

A probe for measurement of related values of cross-sectional area (CA) and pressure has been developed to record characteristics of the walls in luminal organs. The aim of this study was to test the probe in vitro. CA was measured in the range 0.17 to 7.07 cm2 by means of the field gradient principle. Pressure was measured in the range 0 to 20 kPa (150 mmHg) by external transducers. After calibration both the pressure and the CA measuring system did measure the parameters adequately. The CA measuring system was dependent on the temperature and electrolyte concentration of the fluid, but was not affected by the size and form outside the excitation electrodes. The upper frequency limits for recordings of CA and pressure were 15.7 and 0.44 Hz, respectively. These in vitro results indicate that the tube assembly has characteristics sufficient for simultaneous measurement of CA and pressure in sphincter regions. These two variables can be used to describe mechanical wall properties such as compliance, hysteresis and creep.

Animals↗
PubMed1988

Changes in oesophageal wall biomechanics after portal vein banding and variceal sclerotherapy measured by a new technique. An experimental study in rabbits.

The biomechanical properties of the oesophageal wall were investigated in a rabbit model using a four electrode impedance technique. A specially designed probe with the electrodes inside a low pressure expandable insulating latex balloon was introduced in the oesophagus. Stepwise inflation and deflation was done for analysis of oesophageal compliance and hysteresis. The rabbits were allocated to three groups: a control group, one with oesophageal varices and one with varices which were treated by sclerotherapy. The oesophageal varices were induced by portal banding five months before the investigation. A uniform pattern of changes in the biomechanical properties of the oesophageal wall was seen in the group with oesophageal varices when compared with controls. The compliance was significantly decreased, and the hysteresis was lessened. Endoscopic sclerotherapy changed the wall properties to a pattern not distinguishable from normal. Thus, in vivo investigation of the biomechanical wall properties showed a significant loss of distensibility of the oesophagus with varices and restorement of the wall distensibility when the varices were treated with endoscopic sclerotherapy.

Animals↗
PubMed1988

The relation between antral contractile activity and the duodenal component of the migrating motility complex.

The aim of the study was to investigate the relationship between antral and duodenal fasting motor activity in 19 healthy volunteers using a perfused tube assembly with side-holes placed in the distal antrum, second part of the duodenum and in the duodenum near the ligament of Treitz. Registrations were performed until the end of the second duodenal phase III. Eighty-two per cent of the duodenal phases III were preceded by antral activity. The duration of duodenal phase III showed a positive correlation to the preceding number of antral contractions (p less than 0.001) as well as to antral phase III (p less than 0.05), but no correlation to the duration of antral phase III was found. The duration of the migrating motility complex (MMC) showed a positive correlation to the duration of duodenal phase III (p less than 0.05), but no correlation to the preceding number of antral contractions were found. It may be concluded that the level of duodenal activity is very dependent on the preceding antral activity.

Adult↗
PubMed1988

The effects of glucagon and glucagon-(1-21)-peptide on antroduodenal motility in healthy volunteers.

Since it has been argued that the spasmolytic effect of glucagon is related to the first 21 N-terminal amino acid residues, and not to the complete molecule, we have compared the effects of glucagon-(1-21)-peptide (G-(1-21) and glucagon on human antroduodenal motility. Glucagon and G-(1-21) were given as bolus injections to 30 healthy volunteers equally allocated into five groups. Each subject received two doses; one was placebo, 0.25, 0.5, 1.0 or 2.0 mg of glucagon, the other was an equimolar doses of G-(1-21) (placebo, 0.175, 0.35, 0.70 or 1.4 mg of G-1-21). The first injection was given during phase II of a migrating motility complex (MMC), and the next during the following phase II. Contractile activity was recorded using an oral tube with one sidehole positioned in the antrum and two in the duodenum. We confirmed that glucagon decreases the number of contractions in the antrum and duodenum and that normal phase II activity was restored within 20-40 minutes proportionally to the amount of the drug given. G-(1-21) did not change antroduodenal motility nor did it affect the phase II pattern in any of the groups. Neither were any side effects encountered. G-(1-21) does not seem to be an alternative to glucagon and other spasmolytic drugs for obtaining relaxation of the antroduodenal area.

Adult↗
PubMed1988

Long term reproducibility of urodynamic investigations in healthy fertile females.

The long term reproducibility of uroflowmetry, urethral pressure profilometry, cystometry and pressure-flow studies was evaluated in 10 healthy fertile female volunteers over a two year period. All parameters were unchanged, except for an increase in the detrusor pressure. The volume at first sensation, the maximal cystometric capacity and the maximum flow rate, had a coefficience of variation (CV) of 24%, 15% and 21% respectively. The compliance and the opening time however showed a considerably higher CV. Several parameters showed a larger intra individual standard variation (SD) than the interindividual SD, indicating that these parameters should be interpreted with great care. Repetition of the investigations showed in this small material a reduction in the standard error of the mean (SEM). Repeating the investigation reduces the number of patients needed in a clinical trial to obtain a statistically significant change. The study showed that urodynamic investigation is a reliable tool in evaluation of patients over a period of years.

Adult↗