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Biomedical subjects

H Gregersen

Publications and source records attributed to H Gregersen.

At least 73 records · Page 4Linked to original sources
PubMed1991

An alpha 1-adrenoceptor-sensitive mechanism is responsible for the adrenergic inhibition of insulin secretion in the pig pancreas.

The alpha-adrenoceptor subtype mediating inhibition of insulin secretion in the pig was examined in an isolated pancreas preparation perfused with 5 mM glucose. It was found that noradrenaline and the alpha 1-adrenoceptor agonist phenylephrine, but not the alpha 2-adrenoceptor agonist UK 14,304, inhibited insulin secretion. The effect of noradrenaline was abolished by the alpha 1-adrenoceptor antagonist prazosin but was not affected by the alpha 2-adrenoceptor antagonist idazoxan. The inhibitory effect of phenylephrine was also inhibited by prazosin. Thus, in the pig, the alpha-adrenoceptor subtype inhibiting insulin secretion is of the alpha 1-type, which is different from the subtype involved in other species.

Adrenergic alpha-Agonists↗
PubMed1991

Involvement of thin afferents in carpal tunnel syndrome: evaluated quantitatively by argon laser stimulation.

The thin afferent nerves were tested quantitatively by determining the thresholds of warmth and pricking pain to argon laser stimulation and by measuring the brain potentials related to pricking pain. In 27 patients with electrophysiologically verified carpal tunnel syndrome these parameters were measured from fingers 3 and 5 on both hands. All patients had had sensory symptoms ranging from 3 months to 25 years. Both the thresholds were elevated (P less than 0.05) at finger 3 compared to measurements from finger 5, and compared to finger 3 in a group of 39 controls. Four patients with symptoms for more than 7 years had thresholds below the control values. The power of the pain-evoked brain potentials elicited from finger 3 was lower (P less than 0.05) compared to finger 5, and compared to the control group (P less than 0.01). No correlations were found between the measured parameters and the clinical electrophysiological investigation. The findings support previous assumptions that chronic low-force compressions cause impairment of intraneural microcirculation, and hence can affect the function of the thin afferents.

Adolescent↗
PubMed1991

A time-dependent study of passive esophageal wall properties and collagen content in rabbits with esophageal varices.

The passive biomechanical wall properties of the esophagus were studied in rabbits with esophageal varices and controls using a four-electrode impedance technique. Stepwise pressure inflation and deflation was done for analysis of esophageal cross-sectional area, compliance, and hysteresis monthly during six months. At sacrifice, the esophageal collagen content was determined. A small but statistically insignificant increase in compliance was observed during the six-month observation period in both groups. No differences were observed between the groups (P greater than 0.3). No change in hysteresis was observed in either group. The group with esophageal varices had significantly higher collagen content in the distal esophagus when compared to controls (P less than 0.05). No difference was demonstrated in the proximal part. No correlation was demonstrated between the collagen content and esophageal compliance. The study demonstrated that the method allows measurement of luminal cross-sectional area and tissue elasticity. No relationship was found, however, between the collagen content and compliance of the rabbit esophagus.

Animals↗
PubMed1991

Diurnal variation of plasma atrial natriuretic peptide in normals and patients with enuresis nocturna.

The circadian variation of plasma atrial natriuretic peptide (ANP) in relation to urinary excretion of sodium (UNa) and potassium (UK) as well as clearance of creatinine (Ccrea) was assessed in 15 juvenile patients with enuresis nocturna and compared with 11 age-, sex-, and weight-matched normal subjects. Normal juveniles showed a highly significant diurnal variation (p less than 0.001) of plasma ANP with diurnal peak levels at midnight (0000 hours) and minimum levels at 0400 hours. Enuretic patients showed a similar diurnal rhythmicity with normal levels during day and night. In normals both UNa and UK showed significant diurnal rhythmicity with a marked reduction from daytime to night-time. Although the total diurnal excretions of UNa and UK were similar to normals, patients with enuresis showed abnormal diurnal variation in both UNa (p less than 0.05) and UK (p less than 0.01). The abnormal circadian rhythm of UNa and UK in enuretics seemed to be caused by abnormal tubular handling as similar abnormalities were found in the fractional excretions and as the circadian variation of Ccrea was normal. Especially during the first hours of sleep (2200 hours to 0000 hours), the patients showed polyuria (230 +/- 138 ml vs 116 +/- 58 ml, p less than 0.01), natriuresis (20.9 +/- 16.3 mmol l-1 vs 10.7 +/- 6.8 mmol l-1, p less than 0.01), and kaliuresis (7.3 +/- 6.3 mmol l-1 vs 3.7 +/- 2.3 mmol l-1, p less than 0.05), despite normal levels of plasma ANP. In conclusion, the study describes the diurnal variation of plasma ANP in relation to urinary excretion of sodium and potassium in a juvenile normal population. Patients with nocturnal enuresis show abnormal diurnal rhythmicity in the urinary excretion of sodium and potassium that is not correlated to the plasma levels of ANP.

Adolescent↗
PubMed1991

The role of the L-arginine-nitric oxide pathway in relaxation of the opossum lower oesophageal sphincter.

1. The role of the L-arginine-nitric oxide pathway in lower oesophageal sphincter (LOS) relaxation and oesophageal peristalsis was investigated. 2. Twenty four adult opossums were anaesthetized and the right vagus nerve was isolated in the neck and sectioned. Electrical stimulation, applied to the peripheral end of the nerve, resulted in a frequency-dependent relaxation of the LOS, and peristaltic and non-peristaltic contractions in the oesophageal body. 3. N omega-nitro-L-arginine (L-NNA, 10(-8)-10(-5) mol kg-1), an inhibitor of the L-arginine-nitric oxide pathway, inhibited LOS relaxation in a dose-dependent manner, but did not affect resting LOS pressure. At the highest dose of L-NNA no relaxation of the LOS was elicited in response to vagal stimulation. The effect of L-NNA, (10(-5) mol kg-1) was fully reversed by infusion of 10(-4) mol kg-1 L-arginine. Peristaltic velocity and amplitude of contractions in the oesophageal body were unaffected by L-NNA. 4. Infusion of sodium nitroprusside reduced LOS pressure to zero, and the drug was equally potent in control animals (-log ED50:8.1 +/- 0.2 mol kg-1) and in animals pretreated with L-NNA (-log ED50:8.2 +/- 0.3 mol kg-1). This suggests that the effect of L-NNA was not directly on guanylate cyclase. 5. A significant elevation of blood pressure was recorded after administration of L-NNA (10(-5) mol kg-1). 6. It is suggested that the L-arginine-nitric oxide pathway plays an important functional role for relaxation of the LOS, but not for oesophageal peristalsis. Whether the active substance is nitric oxide or a related nitroso-compound remains to be settled.

Animals↗
PubMed1991

Experimental gastrointestinal motility: where to go.

Gastrointestinal motility is a major field of research. However, despite a huge amount of data available in the literature, its exact role has yet to be defined. This paper deals with the choice of animal research models for motility studies.

Animals↗
PubMed1991

Impedance planimetry: a new approach to biomechanical intestinal wall properties.

This paper surveys impedance planimetry, a technique based on the measurement of electrical impedance for estimation of active and passive biomechanical wall properties of the intact intestine. The paper mainly concerns methodological aspects of the recording technique and possible sources of error. Furthermore, the historical background concerning developments of the technique and physiological results during the last two decades are described.

Animals↗
PubMed1991

Biomechanical wall properties of the porcine rectum: a study using impedance planimetry.

The aim was to investigate biomechanical wall properties of the porcine rectum by way of manometry and impedance planimetry. Distension of a balloon inserted into the rectum with definite pressure steps up to 80 cm H2O was done for simultaneous recording of pressure and the balloon cross-sectional area (Bcsa). Viscoelastic wall properties were derived in terms of compliance. Besides eliciting the ascending peristaltic reflex and relaxation of the internal anal sphincter, the balloon inflation elicited a phase of rapid Bcsa increase followed by an accommodation phase of slow Bcsa increase to a steady-state Bcsa, reached within 3 min. The Bcsa increased in a nonlinear way with increasing balloon pressures with only a minimal increase from 70 to 80 cm H2O. Rectal compliance decreased in a nonlinear way with increasing distension pressure.

Animals↗
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↗