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Biomedical subjects

A Thomsen

Publications and source records attributed to A Thomsen.

At least 19 recordsLinked to original sources
PubMed1991

[Screening for neuroblastoma in infants aged 6 months. A method of testing].

In a number of cases, neuroblastoma (NB) may be diagnosed by routine screening of the urine for vanillinic-mandelic acid (VMA) and homovanillinic acid (HVA) in symptomfree infants at the age of six months. Early diagnosis of this disease may possibly improve the prognosis. The object of this project was to establish a method of measuring VMA and HVA concentrations in urine collected on filter paper and to assess participation by the parents as regards three different methods of collecting urine with the object of establishing a population screening programme for NB in Denmark. A total of 1,111 infants aged 6-8 months participated in the investigation. The equipment for testing the urine was given in three different was: 1) By the health nurses (County of Arhus), 2) By the general practitioner at the 6-month vaccination (County of Ringkøbing) and 3) By post (County of Viborg). In Arhus, the health nurses delivered the equipment to 96.7% of the age group concerned. Altogether, urine samples were obtained from 673 infants (61%). Participation was greatest in the County of Arhus (66%) and the County of Ringkøbing (62%) and lowest in the County of Viborg (54%). Two infants were found with marginally raised VMA or HVA but these values were found to be normal on repeated examinations. No cases of neuroblastoma were found in the material nor in the screened group in the course of 1 1/2 years after the conclusion of the investigation. In just over 3% of the cases, renewed urine samples had to be sent on account of too little urine on the filter paper. If current population investigations reveal that screening for neuroblastoma can alter the course of the disease in children, the method described here may form the basis for introduction of population investigations in Denmark.

Denmark↗
PubMed1991

Multipoint linkage analysis in X-linked Alport syndrome.

In order to localize the gene for the X-linked form of Alport syndrome (ATS) more precisely, we performed restriction fragment length polymorphism analysis with nine different X-chromosomal DNA markers in 107 members of twelve Danish families segregating for classic ATS or progressive hereditary nephritis without deafness. Two-point linkage analysis confirmed close linkage to the markers DXS17(S21) (zeta max = 4.44 at theta = 0.04), DXS94(pXG-12) (zeta max = 8.07 at theta = 0.04), and DXS101(cX52.5) (zeta max = 6.04 at theta = 0.00), and revealed close linkage to two other markers: DXS88(pG3-1) (zeta max = 6.36 at theta = 0.00) and DXS11(p22-33) (zeta max = 3.45 at theta = 0.00). Multipoint linkage analysis has mapped the gene to the region between the markers DXS17 and DXS94, closely linked to DXS101. By taking into account the consensus map and results from other studies, the most probable order of the loci is: DXYS1(pDP34)-DXS3 (p19-2)-DXS17-(ATS,DXS101)-DXS94-DXS11 -DXS42(p43-15)-DXS51(52A). DXS88 was found to be located between DXS17 and DXS42, but the order in relation to the ATS locus and the other markers used in this study could not be determined.

Female↗
PubMed1991

Comparison of intravenous and topical lidocaine as a suppressant of coughing after bronchoscopy during general anesthesia.

Twenty-four consecutive patients scheduled for fiberbronchoscopy were randomized to receive double-blind either intravenous (1.5 mg/kg) or laryngotracheal (3 mg/kg) lidocaine to evaluate the influence on post-bronchoscopic laryngospasm, pain in the throat and coughing. Plasma lidocaine concentrations were analyzed 5, 15, 30 and 60 min after administration. None of the patients demonstrated laryngospasm or pain in the throat during the first hour after bronchoscopy. Patients receiving topical lidocaine coughed significantly more than patients receiving intravenous lidocaine, with a median number of coughs of 20 compared to 4, during the first hour (P less than 0.01). The plasma lidocaine concentrations were significantly higher after intravenous than after topical administration (P less than 0.001). After intravenous administration the plasma lidocaine concentrations exceeded the accepted level for potential toxicity in five out of 11 patients, but none of the patients developed toxic symptoms and no side-effects were observed.

Administration, Topical↗
PubMed1990

Evaluation of simple tests for detection of HIV antibodies: analysis of interobserver variation in Tanzania.

200 sera were tested for HIV antibodies with different tests in Tanzania. The results were interpreted by 5 different observers with different laboratory experience. There was considerable variation between observers and between testing methods. HIV-Chek was easiest to perform with little interobserver variation, but a few probably false negative readings were seen. Serodia gave many false positives. Western Blots gave more diverging results due to indeterminate sera and lack of training. HIV-Chek seems best when time, facilities, and training are limited and if combined with Serodia false negative results can be excluded.

Blotting, Western↗
PubMed1979

Measurements of cardiac stroke volume in various body positions in pregnancy and during Caesarean section: a comparison between thermodilution and impedance cardiography.

A total of 220 simultaneous pairs of measurements of cardiac stroke volume were made in twelve women before and during Caesarean section in order to compare impedance cardiography with the thermodilution method. A significantly higher coefficient of correlation was found before (r = 0.77) than during anaesthesia (r = 0.55). Further, there was a significant difference in the slope of the regression lines: before anaesthesia the slope was 1.07 and during anaesthesia with thiopentone, nitrous oxide, oxygen and suxamethonium it was 0.45. Significant changes in the intercept on the Y-axis were found before (-13.9 ml) and during anaesthesia (33.4 ml). When the uterus was displaced upwards and to the left from the 15 degrees tilt position the stroke volume and the cardiac output were increased when measured by both methods to nearly the same values as in the left lateral position. It is concluded that the impedance method is reliable for measuring cardiac stroke volume in late pregnancy under physiological conditions in the conscious patient, but that it cannot replace the thermodilution method in pharmacological studies.

Adult↗
PubMed1978

Flow requirements in the Hafnia modifications of the Mapleson circuits during spontaneous respiration.

The Mapleson A, B, C and D circuits can be changed into non-polluting circuits by employing continuous gas evacuation directly from the circuit, via an ejector flowmeter (Jørgensen 1974); Mapleson A and C circuits with this modification have been described previously as the Hafnia A and C circuits (Christensen 1976, Thomsen & Jørgensen 1976). If evacuation from a closed reservoir is employed, total removal of the expired and surplus gases from the operating theatre is obtained (Jørgensen & Thomsen 1976). There will be resistance to expiration in all the circuits with a relief valve for the discharge of surplus gas. If surplus gas is continuously removed directly from the anaesthetic circuit, the patient breathes in an air compartment at ambient pressure, as long as the removal rate equals the inflow of fresh gas. The relief valve is only included in the circuit to ensure that high pressures do not develop. As in any other circuit, the relief valve remains open except during controlled ventilation. A dumping valve may also be included as a safeguard against low pressures (Jørgensen & Thomsen 1976). The flow requirements of the Hafnia B and D circuits and the corresponding Mapleson circuits have been studied in conscious, spontaneously breathing subjects, and the results are discussed in relation to the flow requirements of other semi-closed system.

Anesthesia, Inhalation↗
PubMed1978

The ejector flowmeter: an evaluation of its accuracy.

The accuracy of five ejector flowmeters was assessed using three different gases and four flow-rates. A soap-bubble flowmeter was used for the calibaration. Significant variations were found between individual flowmeters and between different gas mixtures. No variation was found between the four different flowrates, indicating that the calibration is linear. The mean calibration factor was 84.8% +/- 4.1 (100% O2:87.4 +/- 3.4, 50% N2O/O2: 84.2 +/- 2.8, and 100% N2O: 83.0 +/- 4.6).

Anesthesia, Inhalation↗
PubMed1978

Calculation of oxygen saturation of mixed venous blood in infants.

A retrospective survey of the heart catheterizations of twenty-two children below the age of three years was carried out in order to evaluate different formulae for calculation of the oxygen saturation in mixed venous blood (MVB) from the oxygen saturation in blood from the superior caval vein (SVC) and inferior caval vein (IVC). The formula MVB = (3SVC + IVC)/4 was found satisfactory, also during halothane anesthesia.

Cardiac Catheterization↗
PubMed1978

Effect of a single graded dose of terbutaline tablets in patients with chronic bronchitis and bronchoconstriction. A double-blind, placebo, cross-over study.

Terbutaline, a selective beta2-adrenergic receptor stimulator was given to 10 patients with chronic bronchitis. The effects of the drug were tested by measurements of forced expiratory volume in 1 sec (FEV1), peak expiratory flow rate (PEFR), heart rate, blood pressure and blood gas analysis. The measurements were performed before and 1, 2, 4, 5, and 6 h after oral administration of placebo, 2.5 mg, or 5.0 mg terbutaline. Terbutaline caused a significant dose-related increase in FEV1 and PEFR as compared with placebo. The maximal effects were found at the 4-h measurement and were still present at the measurements performed at 6 h. Heart rate, blood pressure and arterial oxygen tension (PaO2) were not significantly affected. Four patients experienced side effects as tremor and/or heart palpitations. It is concluded that orally administered terbutaline may be an important therapeutical agent in the treatment of chronic bronchitis.

Aged↗
PubMed1977

Measurement of rapid changes in cardiac stroke volume. An evaluation of the impedance cardiography method.

One hundred and twenty-nine simultaneous measurements were carried out on seven patients, 67 at rest and 62 during the Valsalva manoeuvre, in order to compare impedance cardiography with the thermodilution method, during rapid changes in cardiac stroke volume and pulmonary blood volume. A coefficient of correlation of 0.86 was found following linear regression analysis of the whole material. Analysis of the individual patient showed that the mean coefficient of correlation was 0.94 (range 0.91-0.97), and that the slope of the regression lines was 0.41 to 1.82, and further that the mean intercept was 0.2 ml. It is concluded that impedance cardiography can be employed for measuring the relative intraindividual changes in cardiac stroke volume during the Valsalva manoeuvre, and it is suggested that it may be of use in other situations, such as during haemorrhage or continuous positive pressure ventilation.

Adolescent↗