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Biomedical subjects

T Madsen

Publications and source records attributed to T Madsen.

69 records · Page 4Linked to original sources
PubMed1979

Effect of metoclopramide on oesophageal peristalsis and gastro-oesophageal sphincter pressure. A study in normal subjects.

The aim of the present study was to measure the amplitude, the duration, and the velocity of the peristaltic pressure wave in the lower part of the oesophagus in the basal state and at different time intervals after oral intake of 10 and 20 mg metoclopramide. In addition, gastro-oesophageal sphincter pressure was measured in the basal state and 90 min after the intake of metoclopramide. The pressure studies were carried out in eight healthy subjects, using a pressure probe consisting of two open-tip polyethylene catheters that were fed by a capillary tubular system and connected to external pressure transducers. Sphincter pressure was measured (intermittent withdrawal), and the probe was positioned with the distal opening 5 cm orally to the sphincter. Dry and wet (bolus, 5 ml of water) swallows were made in randomized order in the basal state and at the time intervals after the intake of metoclopramide. Finally, the sphincter pressure measurement was repeated. No differences were seen with regard to the peristaltic activity: amplitude, duration, or velocity. Sphincter pressure rose from 12 to 19 mmHg after 10 mg (p less than 0.05) and from 13 to 20 mmHg after 20 mg metoclopramide (p less than 0.05). There were no significant differences between basal values and the response to 10 or 20 mg metoclopramide.

Administration, Oral↗
PubMed1978

Comparative pressure measurements in the oesophagus by means of in situ tip-transducers and external transducer systems.

Basal gastro-oesophageal sphincter pressures and peak peristaltic pressure amplitudes in the oesophageal body 5 and 15 cm proximal to the gastro-oesophageal sphincter were measured with three different set ups in six healthy volunteers. The in situ tip-transducer measurements were compared to two different external pressure transducers in a perfused catheter system and to an external pressure transducer in a non-perfused catheter system. The in situ tip-transducer recorded higher sphincter pressures and peristaltic amplitudes than those recorded by the perfused and non-perfused systems (P less than 0.01). There was no difference between the pressures recorded by perfused systems in conjunction with the different external transducers. The perfused systems recorded sphincter pressures higher than those recorded by the non-perfused systems (P less than 0.02 and P less than 0.01), whereas the non-perfused system recorded higher peristaltic pressure amplitudes than those recorded by the perfused systems (P less 0.01 and P less than 0.01). The importance of the bend of the in situ tip-transducer was shown experimentally. It is concluded that the ideal system for recording oesophageal pressures is a perfused catheter set-up with minimal compliance. The probe with three side holes at the same level ensures registrations of the lowest occlusion pressure at the measuring point.

Adult↗
PubMed1978

Oesophageal peristalsis. A simple system for the recording of oesophageal peristalsis, and the influence of bolus volume on peak peristaltic pressure amplitude.

Peak oesophageal peristaltic pressure amplitude was recorded in 8 healthy subjects at points 5 and 15 cm proximal to the gastro-oesophageal sphincter, by using an in situ tip-transducer simultaneously with a continuous flush (Intraflo) perfused catheter system with external pressure transducer. Dry swallows and wet swallows of 2.5, 5 and 10ml, respectively, were made in random succession. In all cases the pressures recorded by either system correlated well. In all cases the peristaltic pressure amplitude was significantly higher after the wet swallows. The catheter and flow system used in this study is simple and makes recording of peristaltic pressures independent of the shape of the in situ transducer, and its therefore well suited for measuring the amplitude of oesophageal contractions.

Adult↗
PubMed1978

The effect of HCl infusion in the lower part of the oesophagus on the pharyngo-oesophageal sphincter pressure in normal subjects.

A measuring unit combined with a perfused catheter has been developed for measurement of the pharyngo-oesophageal sphincter pressure. The system is able to register pressure measurements using either intermittent or continuous withdrawal of the catheter, at the same flow rate (0.5 ml/min). Repeated measurements of pharyngo-oesophageal sphincter pressure have been made on eight healthy volunteers. No differences were found in the sphincter pressures measured by the continuous and the intermittent withdrawal techniques (p greater than 0.10); the coefficient of variation was 0.18 for both techniques. The pharyngo-oesophageal sphincter pressure was measured during infusion of 0.1 N HCl (5 ml/min) 5 cm proximally to the gastro-oesophageal sphincter. There was an increase in the pharyngo-oesophageal sphincter pressure after 1 min of infusion (p less than 0.05). Measurements after 5 min and 10 min were no different from the initial value; thus a fall was observed between the first and the fifth minute (p less than 0.05). The observed rise in sphincter pressure may be explained as a response acting to prevent gastro-oesophageal reflux from entering the pharynx.

Adult↗
PubMed1978

Bronchoscopy with normoventilation. Automatic ventilation with Sanders technique. A clinical investigation.

Forty six patients, who had to be subjected to diagnostic bronchoscopy under general anaesthesia (thiopental, pethidine, O2-N2O, suxamethonium) were ventilated using Wolf's injectomat (automated Sanders principle) in an attempt to find a setting for the apparatus that would provide normoventilation of the patient, independently of the diagnostic procedure. The first 24 patients were ventilated with the apparatus having a fixed setting: the latter being presumed to provide normo- or hyperventilation. This was confirmed and a steady state of PaCO2 was reached after ventilation for 10 min. This PaCO2 was well correlated with the vital capacity of the patients expressed factorially, in relation to the expected normal value. The investigation renders probable the observation that patients with a greatly reduced vital capacity (less than 50% of the normal value) can rarely be ventilated with the apparatus. On the other hand, a reduced FEV1 has little influence on the efficiency of the apparatus. The apparatus was adjusted in agreement with the above mentioned relation to vital capacity for the following 21 patients, in as much as the change in ventilation was carried out by a change in frequency, while the driving pressure of the apparatus and the inspiration time were maintained unchanged. Normoventilation was obtained in these patients independently of the fact that the bronchoscope was constantly open for the insertion of instruments.

Bronchoscopy↗
PubMed1975

[Determination of intravascular and extravascular lung water after open heart surgery (author's transl)].

Total lung water (169 measurements) and intravascular lung volume (72 measurements) were determined postoperatively on 11 patients with aortic or mitral valve prostheses, by means of thermodilution (diffusable) and cardiogreen (non-diffusable). No loss of heat from the lungs occurred after injection into the trunk of the pulmonary artery and recordings in the left atrium. The admixture of the tracers was satisfactory. The extravascular volume was found to be higher than that measured by other authors, presumably owing to the greater efficacy of the thermodilution technique as compared to the use of tritiated water.

Aortic Valve↗
PubMed1975

Gastro-oesophageal acid reflux. Method for 12-hour continuous recording of oesophageal pH with analysis of records.

Description of method for continuous recording of oesophageal pH and automatic, electronic analysis of records. Stability of apparatus has been tested over 12 hours in the laboratory with different buffer solutions and gastric secretions with and without bile, and on 36 patients with oesophageal disorders. Drift of apparatus max. 0.2 pH units. The analyser, dividing the pH range into arbitrary intervals, performs a rapid and reliable analysis of single examinations from variable criteria. The temporal distribution of pH values into the intervals is expressed in percentages of the total time of recording. Reliability of the analyser was tested by analysis of a simulated pH curve on which changes in amplitude corresponded to the most rapid changes seen in practice. Deviation below one per cent. Repeated analyses of the same records showed a coefficient of variation for the various analytical interval to be 10-0.01 per cent. The method allows recording of the number of reflux episodes, duration of each episode and total duration of pH within chosen limits.

Adult↗
PubMedDate not supplied

MHC variation in birds and reptiles.

The major histocompatibility complex (MHC) has been studied in a multitude of mammals by now, but much less is known about its organisation and variation in other vertebrate species. The mammalian MHC is organised as a single gene cluster, but recent studies on birds suggest that this paradigm of MHC organisation has to be supplemented. The domestic chicken thus possesses two separate gene clusters which both contain MHC class I and class II B genes, and we have shown that the ring-necked pheasant Phasianus colchicus also has two unlinked clusters of class II B genes. We are studying the effect of the MHC on mate choice, survival and reproductive success in natural populations of birds and reptiles. For this reason, we are developing DNA techniques to determine the animals' MHC genotype. The amplification of the hypervariable exon 3 of the class I gene from songbirds and reptiles has provided us with species specific probes that can be used in Southern blot analysis. The first results indicate very extensive variation in all studied species, that is starlings Sturnus vulgaris, great reed warblers Acrocephalus arundinaceus and water pythons Liasis fuscus. The restriction fragment length polymorphism (RFLP) analysis also suggests that the number of MHC genes is significantly larger in these species than in pheasants and domestic chickens.

Animals↗
PubMedDate not supplied

Promiscuity in sand lizards (Lacerta agilis) and adder snakes (Vipera berus): causes and consequences.

We review postcopulatory phenomena in the Swedish sand lizard (Lacerta agilis) and adder (Vipera berus), and in particular, links between female promiscuity, determinants of paternity, and offspring viability. In both species, females mate multiply and exhibit a positive relationship between the number of partners and offspring viability. We conclude that this relationship is most likely the result of variable genetic compatibility between mates arising from postcopulatory phenomena, predominantly assortative fertilization with respect to parental genotypes. However, males who were more successful at mate acquisition were also more successful in situations of sperm competition, suggesting a possible link between male (diploid and haploid) genetic quality per se and probability of fertilization. Neither the number of partners nor the number of matings influenced the risk of infertility in sand lizards, suggesting that selection for reduced risk of infertility is not a sufficient explanation for maintaining female promiscuity in this population. Finally, we conclude that the relatively low genetic variability exhibited by our study populations may have facilitated detection of genetic benefits compared to more outbred ones. However, recent work derived from outbred populations in other taxa suggest a greater generality of the principles we discuss than previously may have been appreciated.

Animals↗
PubMedDate not supplied

Sympathetic influence on the normal Eustachian tube. An experimental study in the rat.

A new variant of the inflation test of the Eustachian tube is presented; a constant air flow generator was constructed with minimal sensitivity to counterpressure, and variations in air pressure were measured, reflecting variations in Eustachian tube patency. By means of this test the effect of Otrivin (alpha 2-receptor stimulation) and Timacar (beta-receptor blocking) on the Eustachian tube was investigated with saline serving as reference. The following results were obtained: Otrivin lowers the opening pressure and the steady state pressure, and reduces the pressure drop during active opening. Timacar alone has no statistically significant effect on the Eustachian tube, but the combined effect of the two drugs is a more pronounced decrease in steady state pressure than the decrease seen following alpha 2-adrenergic stimulation alone. An explanation could be an alpha 2-receptor modulation by the beta-blocking agent. Consequently, autonomous regulation should be further studied in the search for a better understanding of Eustachian tube physiology.

Adrenergic alpha-Agonists↗
PubMedDate not supplied

Right atrial temperature and electrical activity during cardioplegic cardiac arrest.

In 18 patients undergoing coronary artery bypass surgery the relation between right atrial temperature and right atrial electrical reactivation during cardioplegic cardiac arrest was studied. The administration of cardioplegic solution induced immediate ventricular and atrial arrest in all patients. No recurrence of ventricular activity was observed while right atrial activity subsequently recurred in 11 patients. Activity at the surface ECG was recorded only in one patient with right atrial reactivation. No right atrial electrical activity was found below 19 degrees C. The average atrial temperature was 21.5 degrees C while the average apex temperature was 15 degrees C. The study has confirmed previous observations that during cardioplegic cardiac arrest the right atrium is not as well protected as the ventricular tissue against rewarming. Monitoring of the right atrial electrical activity or right atrial temperature is essential to ensure atrial arrest during the entire period of cardioplegic cardiac arrest.

Bicarbonates↗
PubMedDate not supplied

Left coronary artery originating from the pulmonary artery correction and total myocardial blood flow measurements.

In a boy aged 12 years correction of an anomalous coronary artery system was performed by suture of the left coronary artery origin at the pulmonary artery trunk and a vein by-pass to the proximal LAD. Peroperative blood flow gives values for myocardial perfusion before and after by-pass with relation to patency of the vein graft. Before correction pure coronary blood flow was 540 ml/min, shunt flow 540 ml/min; in total 1,080 ml/min through the right coronary artery. After correction the vein by-pass conducted 310 ml/min and the right coronary artery 180 ml/min. At follow-up 2 months later coronary angiography showed a normal right coronary artery without collateral connections to the left coronary artery system which was well perfused from the by-pass. Left heart hypertrophy was reduced from 568 ml/m2. A weak systolic murmur at the apex could be a slight unimportant mitral insufficiency.

Blood Flow Velocity↗