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Biomedical subjects

E Pedersen

Publications and source records attributed to E Pedersen.

At least 19 recordsLinked to original sources
PubMed1992

Intravenous versus subcutaneous administration of recombinant human erythropoietin in patients on haemodialysis and CAPD.

The most effective route of administration of rHuEpo is still a matter of discussion. Prospectively we studied subcutaneous (s.c.) versus intravenous (i.v.) administration in three comparable groups of patients; HD-s.c. (n = 9), HD-i.v. (n = 11), and CAPD-s.c. (n = 9). All the groups initially received 50 units/kg three times weekly. During the first 8 weeks dose adjustments were made only if target haemoglobin exceeded 11.3 g/dl (7 mM). Target haemoglobin was reached after 84 (42-98) days in the i.v. group and 42 (14-77) and 42 (28-56) respectively in the HD-s.c. and CAPD groups. The difference was statistically significant (P less than 0.05). Even the cumulative doses to reach target haemoglobin were significantly less in the two s.c. groups. To maintain haemoglobin at about 11.3 g/dl, weekly doses were as follows: HD-i.v. 125 U/kg (86-168), HD-s.c. 63 U/kg (20-85), and CAPD 72 U/kg (31-100). The total observation time after the target haemoglobin level was reached, was median 130 (114-264) days. The difference between the i.v. group and the two s.c. groups was statistically significant, (P less than 0.05) whereas there was no difference between the s.c. groups. We conclude that s.c. administration of rHuEpo is more effective in induction as well as in maintenance therapy and that s.c. administration is equally efficient in HD and CAPD patients.

Adolescent↗
PubMed1991

Tooth displacement analysed on human autopsy material by means of a strain gauge technique.

Tooth displacement was analysed on human autopsy material for various types of orthodontic force systems using an electronic strain gauge technique. Tooth movements were registered in two dimensions with low force clip gauges on three sections of the mandible, containing the first premolar and the first molar. The sensitivity was 0.1 microns when horizontal forces of 50, 100, and 150 cN were applied at different horizontal levels producing different M/F ratios. The relationship between a force system and the resulting tooth movement was described by the position of the centre of rotation, CR, and the angle of rotation. The centre of resistance was determined for the three autopsy specimens, and depended on tooth geometry, root length, and level of bony margin. Important differences in location were found. The dynamics of initial tooth movement were analysed within the first minute of load application. Force/displacement curves were generated to evaluate the behaviour of the periodontal ligament. There was a linear correlation between the two variables. Freezing the autopsy material some days before testing had no detectable effect. The results from measurements on human autopsy material were compared with previously derived in vivo measurements.

Adolescent↗
PubMed1991

Location of centres of resistance for maxillary anterior teeth measured on human autopsy material.

The location of the centre of resistance (CR) of various consolidated units of maxillary anterior teeth was determined in this study using human autopsy material. The units studied consisted of two central incisors, four incisors, and six anterior teeth. When horizontal forces were applied the CR for the two- and six-tooth units was located approximately 6.5 mm apical to the bracket position. For the four-tooth unit, CR was placed slightly more occlusally, the distance being 5.0 mm. Applying vertical forces CR was located about 13.0 mm posterior to the bracket position for the two- and four-tooth unit. The incorporation of the canines into the incisor segment resulted in a distal shift of CR of 6 mm. CR for the six anterior teeth was, thus, located on a line 3 mm behind the distal surface of the canines. Increasing force levels had little effect on the location of CR for a given unit.

Adult↗
PubMed1991

Urinary excretion of N-nitrosoproline in relation to consumption of raw and cooked vegetables in a Danish rural population.

Several recent case-control studies of gastric cancer have demonstrated the protective effect of consumption of vegetables. According to Correa's model of gastric carcinogenesis, the initiating agent is N-nitroso compounds either ingested or formed in vivo. In our study of endogenous nitrosation, we measured intragastric formation of N-nitroso compounds in 285 individuals by the nitrosation of proline; in this presentation we analysed the effect of consumption of vegetables on urinary excretion of N-nitrosoproline (NPRO). When adjustment was made for the dominating determinants of NPRO excretion (total nitrate intake and tobacco smoking), a marked difference in the effects of consumption of raw and cooled vegetables was seen: consumption of cooked vegetables increased endogenous nitrosation of proline, while consumption of raw vegetables had only a marginal effect. We suggest that the difference between raw and cooked vegetables is due to destruction of ascorbate in the cooking of the vegetables. The lack of a protective effect of consumption of raw vegetables on the rate on endogenous nitrosation of proline indicates, however, that the determinants of nitrosation of proline and the determinants of gastric cancer risk may be different.

Cooking↗
PubMed1990

[Helicobacter pylori infection among employees at the gastroenterologic section, Haukeland Hospital].

Using the C-14 urea breath test we estimated the gastric urease activity among 46 healthy Norwegians, all employed at the section of gastroenterology, Haukeland Hospital, Norway. The overall prevalence of Helicobacter pylori-infection (30.4%) is similar to that reported previously among healthy subjects outside hospitals. The tendency towards higher prevalence among the gastroenterologists (41.7%) may be accounted for partly by the preponderance of males in this profession. The results do not support the notion that gastroenterologists are more liable to attract gastric H pylori-infection than other hospital personnel.

Adult↗
PubMed1990

Monitoring of renal allografts by Doppler ultrasound: precision and reference values.

The Doppler ultrasound method was used to obtain blood flow velocity curves from one of the large segmental arteries near the pelvis of transplanted renal allografts. The precision of the method for estimation of the pulsatility index (PI), the ratio between the peak systolic and the least diastolic velocity (A/B ratio) and the ratio of the are under the velocity curve of the first half and the second half of the cardiac cycle (AUC 1/2 ratio) was tested in vivo by examination of six renal allograft patients eight times. Two investigators examined each patient twice in random order upon two successive days. To investigate variation with time the same 10 patients were examined four times with 6-8 week intervals. To establish normal ranges for the PI, the A/B ratio and the AUC 1/2 ratio, a cross-sectional study of 54 patients with stable and well-functioning renal allografts was performed. No systematic variation was found between observers, days or repeated observations. The mean coefficient of variation was 8.3% for the pulsatility index, 5.8% for the A/B ratio and 14.9% for the AUC 1/2 ratio. The longitudinal study showed no systematic variation of the indices with time. For the 54 patients in the cross-sectional study the mean pulsatility index was 0.78, the mean A/B ratio 2.62 and the mean AUC ratio 1.82.

Blood Flow Velocity↗
PubMed1990

Doppler ultrasound in the diagnosis of renal allograft rejection and in monitoring the effect of treatment.

Thirty-six consecutively transplanted renal allograft patients were prospectively monitored with ultrasound-Doppler examinations three times weekly during the first 3 weeks after transplantation. Although triple-immunosuppressive therapy consisting of cyclosporin A, azathioprine and prednisolone was used, acute rejection occurred in 11 patients. Nine patients had immediate onset of graft function and no rejection. Ten patients had acute tubular necrosis (ATN) without any signs of rejection and were treated with dialysis for 1-3 weeks after transplantation. Thrombosis of the renal artery was diagnosed in four patients. During rejection episodes pulsatility index (PI) was above normal range in all patients. In patients with mild to moderate ATN and PI was normal throughout the clinical course whereas two patients with severe ATN but no signs of rejection in the kidney biopsy also had high PI. It is concluded that serial Doppler velocity examination after kidney transplantation is a non-invasive, cheap and reliable method for monitoring of the graft. The method can be used in the early diagnosis of rejection, and it is of special value in monitoring grafts without function.

Azathioprine↗
PubMed1990

Electronic determination of centres of rotation produced by orthodontic force systems.

A strain gauge measurement device with low force clip gauges, for measurement of initial tooth displacement in two dimensions has been developed. An experimental model simulating a maxillary central incisor is loaded with different known and controlled force systems. The resulting tooth displacements are described by the position of the centre of rotation and the generated angle of rotation for the total tooth movement. The effect of a single force, a moment, and force-moment combinations producing different moment to force ratios were studied. From these results the required force system needed to produce tooth movements with different centres of rotation for a central incisor of average root length are calculated. Furthermore, the model allows us to measure the accuracy of the measuring device by comparing results to analytical and laser holographic data, obtained on similar models. Some preliminary measurements and results, using human autopsy material are presented.

Adult↗
PubMed1990

Comparison of induction with and first hour of recovery from brief propofol and methohexital anesthesia.

Anesthesia and recovery during the first hour after propofol and methohexital anesthesia for termination of pregnancy, lasting about 12 min, were compared, the latter in a double-blind manner by means of psychomotor tests (coin counting and continuous auditory reaction time). Muscle movements and hiccups were seen significantly more frequently during methohexital inductions. No differences were seen regarding pain at the site of injection or apnea between the groups. At 15 min after the last dose of anesthetic, recovery after methohexital was ahead of that after propofol, but after 1 h, psychomotor performance was better in the propofol group. Side-effects during recovery were few, and incidences did not differ significantly. Although the difference in reaction time test was significant, it was hardly large enough to be of any clinical importance. Both drugs are useful for brief outpatient anesthesia, but smoother induction gives propofol an edge over methohexital.

Abortion, Induced↗
PubMed1989

Endogenous nitrosation in relation to nitrate exposure from drinking water and diet in a Danish rural population.

Increasing levels of nitrate in drinking water is of concern due to the possibility of an associated increase in long-term exposure to endogenously formed carcinogenic N-nitroso compounds. Excretion of N-nitrosoproline in 12-h overnight urine after intake of 500-mg L-proline was used to quantify the rate of endogenous nitrosation in 285 individuals in an area in northern Denmark with large variation in nitrate concentration of the drinking water. Nitrate intake was measured in a 24-h duplicate diet sample. The crude association between nitrate concentration in drinking water and rate of endogenous nitrosation in individuals is only weakly positive and not quite statistically significant (P = 0.08). The risk of having detectable nitrosation increases significantly with total nitrate intake and tobacco smoking. In nonsmokers, nitrosation is determined by nitrate intake. Smokers have increased nitrosation which does not depend on nitrate intake. Effect modification through dietary factors was evaluated and indicated a protective effect of tea consumption, while the effect of eating vegetables was not clear-cut. The experimental design (12-h urine sample; proline dose taken in the evening) is likely to underestimate the effect of nitrate in drinking water relatively to nitrate in the diet.

Denmark↗
PubMed1989

Nitrate exposure from drinking water and diet in a Danish rural population.

Increasing levels of nitrate (NO3-) in drinking water in Denmark is of concern due to the possibility of an associated increase in long-term exposure to endogeneously formed N-nitroso compounds. Using a duplicate portion technique in combination with a qualitative description of diet and other background variables, the total nitrate intake in a Danish rural population and the contribution of drinking water to the total nitrate exposure is estimated. People drinking nitrate-free water have an intake of 37 mg NO3- per day. At 47 mg NO3- per litre, the exposure is increased to 89 mg, about 60% of which originates from the water. At 84 mg NO3- per litre, the daily exposure is 123 mg, 70% of which originates from the drinking water. These crude comparisons between three groups of people are supplemented with quantitative modelling of nitrate exposure at individual level. Apart from drinking water, consumption of vegetables is a major source of nitrate in this population. Using nitrate in overnight urine samples to quantify exposure is less accurate than the duplicate dietary portion technique and tends, in the present study, to underestimate the contribution of water-derived nitrate to total nitrate intake.

Adult↗
PubMed1986

Experimental electrical stimulation of the bladder using a new device.

Repeated bladder contractions were evoked during a six month period in three unanaesthetized female minipigs by using unipolar carbon fiber electrodes embedded in the bladder wall adjacent to the ureterovesical junction. In contrast to bipolar and direct bladder muscle stimulation unipolar electrodes at each ureterovesical junction evoked bladder pressure increase similar to those produced in previous investigations in dogs. Sacral nerve stimulation of S2 evoked bladder contraction at a minimal current. Microscopic examination revealed no cellular reactions to the carbon fibers but a subcutaneous reaction to the receivers was seen and was thought to be due to mechanical irritation. The clinical implication of the findings is discussed.

Animals↗
PubMed1986

Interferon induction, 2'-5' oligo A synthetase and lymphocyte subpopulations in out-patients with multiple sclerosis in a longitudinal study.

Nine patients with multiple sclerosis, four with relapsing-remitting disease, and five with chronic progressive disease, together with eight healthy control, were followed for nearly a year with monthly clinical and laboratory examinations. Alpha- and gamma-interferon was induced in lymphocytes with different viruses and PHA, no differences were found between healthy controls and multiple sclerosis patients. The alpha- and gamma-interferon induced enzyme 2'-5' oligo A synthetase in lymphocytes was found to have a tendency to be lower in multiple sclerosis patients than in healthy controls. When medians of ratios of helper/suppressor blood lymphocytes in multiple sclerosis patients were compared with healthy controls, the same results were found, although higher values of ratios were found among the patients and the highest value was found in a patient with chronic progressive disease. No correlation to disease activity could be found in interferon inductions, 2'-5' oligo A synthetase concentrations and ratios of OKT4/OKT8. In particular no change in ratio was found in relation to five exacerbations taking place in the four multiple sclerosis patients with acute relapses.

2',5'-Oligoadenylate Synthetase↗