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Biomedical subjects

P Pedersen

Publications and source records attributed to P Pedersen.

At least 19 recordsLinked to original sources
PubMed2005

Influence of ionizing radiation on nucleus 24 cochlear implants.

HYPOTHESIS: To evaluate the influence of conventional or hyperfractionated radiotherapy on Nucleus CI24M or CI24R(CS) implant systems. BACKGROUND: As a consequence of more than 70,000 cochlear implant recipients worldwide, the potential need for radiotherapy is an issue requiring consideration by both implantees and implantation centers. Conditions requiring radiotherapy of the head may include head, neck, or brain tumors. METHODS: The study examines the effect of ionizing radiation on cochlear implant function. The implanted devices examined were the Nucleus CI24M and Nucleus CI24R(CS). In a modeled study, two implants of each type were treated with fraction schemes most frequently used in clinical routine (e.g., conventional fractionation [total dose, 120 Gy] and hyperfractionation [total dose, 116 Gy]). Parameters quantified were the implant output amplitude changes at high and low current level (current levels 255 and 100, respectively), the charge balance of the biphasic pulse, and the accuracy of the impedance telemetry function. RESULTS: Within the clinically relevant dose range (< 80 Gy), implant function in all four devices was normal. Failure occurred in one Nucleus CI24R(CS) device treated with hyperfractionation. A dramatic drop in the output amplitude at 106 Gy was observed, and the impedance measurement failed at a total dose of 111 Gy. CONCLUSION: The results suggest that conventional or hyperfractionated radiotherapy can be applied safely at Nucleus CI24M or CI24R(CS) implant systems in a patient-like setting. Therefore, the authors propose that the results of the study can be applicable in clinical practice.

Cochlear Implants↗
PubMed2003

Evidence that the Cys282Tyr mutation of the HFE gene originated from a population in Southern Scandinavia and spread with the Vikings.

Hereditary hemochromatosis has been recognized as a clinical disorder for more than 100 years. The common form of the disorder is caused by the Cys282Tyr mutation (C282Y) of the HFE gene. Hereditary hemochromatosis affects predominantly people of Northern European origin. The C282Y mutation probably occurred on a single chromosome carrying the ancestral hemochromatosis haplotype, which subsequently was spread by emigration and the founder effect. It has been estimated that the C282Y mutation appeared 60-70 generations ago. It was initially suggested that the ancestral C282Y mutation occurred within the Celtic group of peoples. However, we hypothesize that the distribution of the C282Y mutation in Europe is more consistent with an origin among the Germanic Iron Age population in Southern Scandinavia. From this area, the mutation could later be spread by the migratory activities of the Vikings. The aim of the present study was to evaluate the validity of these two hypotheses. Several arguments are in favor of the 'Viking hypothesis': first, the highest frequencies (5.1-9.7%) of the C282Y mutation are observed in populations in the Northern part of Europe, i.e. Denmark, Norway, Sweden, Faeroe Islands, Iceland, Eastern part of England (Danelaw) and the Dublin area, all Viking homelands and settlements. Second, the highest allele frequencies are reported among populations living along the coastlines. Third, the frequencies of the C282Y mutation decline from Northern to Southern Europe. Intermediate allele frequencies (3.1-4.8%) are seen in the populations in Central Europe, which is the original Celtic homeland. Low allele frequencies (0-3.1%) are recognized in populations in Southern Europe and the Mediterranean.

Amino Acid Substitution↗
PubMed2003

Children with nutritional rickets referred to hospitals in Copenhagen during a 10-year period.

AIM: To describe the prevalence of nutritional rickets among children admitted to three large paediatric departments in the Copenhagen area during a 10 y period. METHODS: Retrospective analysis of cases identified from the diagnosis registers fulfilling the diagnostic criteria for nutritional rickets. RESULTS: Forty cases were identified, distributed in two distinct age groups: 0.5-4 y (n = 31) and 9-15 y (n = 9). All cases were immigrants, of whom 95% were born in Denmark. The main symptoms in the younger age group were bowed legs and clumsy walk, and in the peripubertal group were painful joints. Two children had generalized convulsions. None of the cases had received vitamin D supplementation. CONCLUSION: Nutritional rickets is still present among immigrants in Denmark, and it is likely that the prevalence of mild cases is high. Prevention through vitamin D supplementation is important, but requires a dedicated health education effort.

Child Nutritional Physiological Phenomena↗
PubMed2002

HFE mutations and hemochromatosis in Danish patients admitted for HFE genotyping.

Analysis of the common C282Y and H63D mutations in the HFE gene is widely used to diagnose hereditary hemochromatosis (HH). The aim of this study was to evaluate the efficiency with which different hospitals and general practitioners select patients for HH genotype and to determine the distribution of HFE mutations in such patients. Nine hundred unrelated patients from Danish hospitals and general practitioners (group A) and 69 consecutive patients from a specialized liver unit (group B) were examined for HFE substitutions using multiplex real-time polymerase chain reaction. In group A we found 13.0% (0%) C282Y homozygotes, 5.8% (2.6%) H63D/C282Y compound heterozygotes and 1.9% (3.1%) S65C heterozygotes. The values for 420 Danish blood donors are shown in parentheses. The distribution of genotypes in group B was similar to that of the blood donors. Serum ferritin, transferrin iron saturation and pathological data were collected from 38 randomly selected C282Y homozygotes, 36 H63D/C282Y compound heterozygotes, 19 H63D heterozygotes, 17 S65C heterozygotes and 144 wild-types. All of the C282Y homozygotes and 28% of the compound heterozygotes were diagnosed as HH patients. There was no evidence of HH in the H63D homozygotes or S65C heterozygotes. Moreover, 7 wild-type patients, 2 C282Y heterozygote patients and one H63D heterozygote patient fulfilled the criteria for HH. The significant enrichment of HH among associated genotype samples submitted for HFE testing indicates that the clinical selection is generally adequate. However, the study showed substantial deviation in the selection efficiency among the various hospitals and general practitioners.

Blood Donors↗
PubMed2001

Clinically overt hereditary hemochromatosis in Denmark 1948-1985: epidemiology, factors of significance for long-term survival, and causes of death in 179 patients.

The object was to analyze, in a nationwide survey, the incidence and course of hereditary hemochromatosis in relation to the degree of iron overload and the presence of organ damage. The study included 179 Danish Caucasian patients with clinically overt hemochromatosis diagnosed between 1948 and 1985. A cohort of 158 patients was followed for a median of 8.5 years (range: 0.2-29.5). From 1951 to 1975, the yearly relative incidence rate was constant: 0.58/100,000 persons >20 years of age. From 1981 to 1985, the yearly relative incidence rate rose to 1.40/100,000 persons >20 years of age. Survival was reduced in the entire series when compared with a matched control population ( p<0.0001). There was a steady increase in survival from 1948 to 1985 ( p<0.002). Survival was significantly reduced in patients with liver cirrhosis and/or diabetes mellitus ( p<0.01). In contrast, survival in patients without cirrhosis or diabetes was similar to rates expected. Survival in patients with arthropathy was higher than in patients without joint affection ( p<0.004). Patients adequately treated with phlebotomy ( n=66) had a higher survival than inadequately treated patients ( n=62; p<0.0001). Adequately treated patients with cirrhosis and/or diabetes had better survival than inadequately treated patients with similar organ damage ( p<0.001). The main causes of death were hepatic failure due to cirrhosis (32.0%) and cirrhosis with liver cancer (23.1%). Sharpened diagnostic awareness has improved early diagnosis and increased the diagnostic frequency of clinical hemochromatosis. Adequate phlebotomy treatment was the major determinant of survival and markedly improved prognosis. Early detection and treatment of this common iron overload disorder is crucial and can completely prevent any excess mortality caused by hemochromatosis.

Adult↗
PubMed2001

Pulse oximetry for perioperative monitoring.

BACKGROUND: Monitoring with pulse oximetry might improve patient outcome by enabling an early diagnosis and consequently, correction of perioperative events that might cause postoperative complications or even death. Only a few randomised clinical trials of pulse oximetry have been performed during anaesthesia and in the recovery room which describe perioperative hypoxaemic events, postoperative cardiopulmonary complications and cognitive dysfunction. OBJECTIVES: To study the effect of perioperative monitoring with pulse oximetry to clearly identify the adverse outcomes that might be prevented or improved by the use of pulse oximetry. SEARCH STRATEGY: Trials were identified by computerised searches of the Cochrane Library, MEDLINE, EMBASE, and by checking the reference lists of trials and review articles. SELECTION CRITERIA: All controlled trials that randomised patients to either pulse oximetry or no pulse oximetry during the perioperative period, including the operating and recovery room. DATA COLLECTION AND ANALYSIS: We collected data in relation to events detectable by pulse oximetry, any serious complications that occurred during anaesthesia or in the postoperative period, intra- or postoperative mortality, and duration of recovery or intensive care stay. Formal statistical synthesis of individual trials was not performed in view of the variety of outcomes studied. MAIN RESULTS: Searching identified six reports; four studies with data from a total of 21,773 patients were considered eligible for analysis. Only two studies specifically addressed the outcomes in question; both found no effect on the rate of postoperative complications using perioperative pulse oximetry. Two studies used hypoxaemia detectable by pulse oximetry to assess the value of perioperative monitoring, although outcomes were not given. It was found that hypoxaemia was reduced in the pulse oximetry group both in the operating theatre and in the recovery room. During observation in the recovery room, the incidence of hypoxaemia in the pulse oximetry group was 1.5-3 times less. The postoperative cognitive function using the Wechsler memory scale and continuous reaction time was independent of perioperative monitoring with pulse oximetry. The other study showed that postoperative complications occurred in 10% of the patients in the oximetry group and in 9.4% in the control group. The two groups did not differ in cardiovascular, respiratory, neurologic, or infectious complications. The duration of hospital stay was a median of 5 days in both groups, and an equal number of in-hospital deaths was registered in the two groups. REVIEWER'S CONCLUSIONS: The studies confirmed that pulse oximetry can detect hypoxaemia and related events. However, we have found no evidence that pulse oximetry affects the outcome of anaesthesia. The conflicting subjective and objective results of the studies, despite an intense, methodical collection of data from a relatively large population, indicates that the value of perioperative monitoring with pulse oximetry is questionable in relation to improved reliable outcomes, effectiveness and efficiency.

Humans↗
PubMed2001

Cerebral response to electric stimulation of the colon and abdominal skin in healthy subjects and patients with irritable bowel syndrome.

BACKGROUND: Visceral hyperalgesia may play an important part in the pathophysiology of the irritable bowel syndrome (IBS). We investigated the neuronal afferent pathways in healthy volunteers and IBS patients by recording evoked potentials (EPs) elicited by electrical stimulation of the colon and abdominal skin inside and outside the referred pain area. METHODS: Six healthy subjects and nine IBS patients met the inclusion criteria. Morphology and topography of EPs to painful electrical stimuli were estimated in the rectosigmoid junction and on the skin inside/outside the referred pain areas. RESULTS: The EPs to painful stimuli of the gut showed a shorter latency and a smaller amplitude of the first positive peak (P1) in the IBS group. The controls had a mid-latency frontal positive component after 100 ms, whereas no reliable early activation was seen in the IBS patients. In controls, a single late (>150 ms) positive component was seen, whereas the late component was biphasic in the IBS group. The EPs to painful stimuli of the two skin areas differed in IBS patients, but not in controls. CONCLUSION: Differences in the EPs to electrical painful stimulation of the sigmoid colon and skin inside/outside the experimentally evoked referred pain area were seen comparing healthy subjects and IBS patients. The results indicate altered central nervous system responses.

Abdomen↗
PubMed2000

Nonsteroidal progesterone receptor ligands with unprecedented receptor selectivity.

We have characterized a series of nonsteroidal progesterone receptor ligands, the tetrahydropyridazines. Compounds in this series, exemplified by RWJ 26819, demonstrate high affinity and unprecedented specificity for the progesterone receptor relative to other steroid hormone receptors. Like steroidal progestins, RWJ 26819 induces binding of the receptor to a progesterone response element in vitro, and stimulates gene expression in and proliferation of T47D human breast cancer cells. When administered to rabbits orally or subcutaneously, the compound induces histological changes in the uterine lining comparable to those induced by levonorgestrel. It also inhibits ovulation in monkeys. Though less potent in cells and in animal models than would be predicted from binding affinity alone, their enhanced selectivity suggests that they could be effectively used in a clinical setting. Most of the tetrahydropyridazines synthesized are progestin agonists or mixed agonists and antagonists in vitro; however, one compound with antagonist activity in the rabbit uterine transformation assay has been identified.

Alkaline Phosphatase↗
PubMed1999

[Cryptorchism. Outcome of treatment and referral patterns in an unselected group of patients in a 3-year period].

The age of diagnosis and referral together with the efficacy of HCG treatment were studied retrospectively in 196 unselected cryptorchid patients seen over a period of three years. The median age of diagnosis was 2 years and 7 months, whereas the median age of referral was three years later. During the period of study, guidelines for referral and therapy were published in a nationwide journal and in the local region, and a slight but significant fall in age of referral was seen thereafter. The median age of treatment with HCG, 92 patients, was 6 years and 11 months, and median age of surgery, was 7 years and 7 months. The rate of success with HCG was for bilateral testes 41% and for unilateral testes 21%, giving an overall success rate of 30%. This result is lower than previously reported, which is most likely explained by a higher suprascrotal position of testes before treatment. Guidelines and recommendations for referral and therapy seem to influence the time of referral, which is, however, in this study not in accordance with the consensus of definitive treatment before the age of two years. Early diagnosis is recommended and should be followed by referral to a paediatric department with particular interest and knowledge about cryptorchidism.

Adolescent↗
PubMed1999

A polymorphic variant in the human electron transfer flavoprotein alpha-chain (alpha-T171) displays decreased thermal stability and is overrepresented in very-long-chain acyl-CoA dehydrogenase-deficient patients with mild childhood presentation.

The consequences of two amino acid polymorphisms of human electron transfer flavoprotein (alpha-T/I171 in the alpha-subunit and beta-M/T154 in the beta-subunit) on the thermal stability of the enzyme are described. The alpha-T171 variant displayed a significantly decreased thermal stability, whereas the two variants of the beta-M/T154 polymorphism did not differ. We wished to test the hypothesis that these polymorphisms might constitute susceptibility factors and therefore determined their allele and genotype frequencies in (i) control individuals, (ii) medium-chain acyl-CoA dehydrogenase-deficient patients homozygous for the K304E mutation (MCAD E304), (iii) a group of patients with elevated urinary excretion of ethylmalonic acid (EMA) possibly due to decreased short-chain acyl-CoA dehydrogenase activity, and (iv) in patients with proven deficiency of very-long-chain acyl-CoA dehydrogenase (VLCAD). No significant overrepresentations or underrepresentations were found in the first two patient groups, suggesting that the polymorphisms studied are not significant susceptibility factors in either the MCAD E304 or the EMA patient group. However, in the VLCAD deficient patients the alpha-T171 variant (decreased thermal stability) was significantly overrepresented. Subgrouping of the VLCAD patients into three phenotypic classes (severe childhood, mild childhood, and adult presentation) revealed that the overrepresentation of the alpha-T171 variant was significant only in patients with mild childhood presentation. This is compatible with a negative modulating effect of the less-stable alpha-T171 ETF variant in this group of VLCAD patients that harbor missense mutations in at least one allele and therefore potentially display residual levels of VLCAD enzyme activity.

Acyl-CoA Dehydrogenase, Long-Chain↗
PubMed1998

[Myocardial rupture during exercise ECG].

We report a case of heart rupture in connection with a stress test performed nine days after an otherwise uncomplicated myocardial infarction. The Danish Association of Cardiologists recommend stress testing 5-20 days after myocardial infarction. We question whether this timing is appropriate considering the vulnerability of the myocardium at that time.

Aged↗
PubMed1998

Small intestinal transit time and intraluminal pH in ileocecal resected patients with Crohn's disease.

The pH and transit times of the gut are important for the delivery of active drug from several tablets used in the treatment of Crohn's disease (CD). Many patients with CD undergo an ileocecal resection, which might influence small intestinal pH and transit time. The effect of ileocecal resection on these variables has not previously been studied. Intraluminal pH and transit time were measured in nine ileocecal-resected CD patients and 13 healthy volunteers using pH-sensitive radiocapsules. Small intestinal transit time (SITT) was significantly shorter in ileocecal-resected patients (5.2 hr, controls 8.0 hr). The pH levels of the small intestine were identical in patients and controls, whereas cecal pH was 0.9 pH units higher in resected CD patients. The time spent with pH higher than 5.5, 6.0, 6.5, and 7.0 was significantly shorter in patients than in controls. There was no correlation between the SITT and the length of resected ileum or between the SITT and the time elapsed since the resection. We conclude that ileocecal resection decreases the SITT and the time with pH higher than 5.5-7.0. The study indicates that this reduction of the SITT is mainly due to the resection of the ileocecal valve and is, to a certain extent, independent of the length of resected ileum. An ileocecal resection might therefore affect the delivery of active drug from tablets with pH-dependent delivery.

Adult↗
PubMed1998

Epidemiology of respiratory syncytial virus infection requiring hospitalization in East Denmark.

BACKGROUND: Prophylaxis against infection caused by respiratory syncytial virus (RSV) with high titered RSV immunoglobulin or humanized antibody may soon be available in Europe. OBJECTIVE: To study the epidemiology of RSV infections requiring hospitalization in infants <6 months in East Denmark to provide a rational basis for decisions concerning prophylaxis against RSV. METHOD: Populat ion-based retrospective review of case records of infants <6 months admitted to pediatric departments with RSV infection in East Denmark from November 1, 1995, to April 30, 1996. RESULTS: Data were obtained from 459 infants. Seventy-three had predisposing conditions: prematurity, 49; pulmonary disease, 2; congenital heart disease, 7; neurologic disease, 6; others, 9. One preterm infant had bronchopulmonary dysplasia. The incidence of RSV infection requiring hospitalization in East Denmark among infants <6 months was estimated to be 34/1000/season. It was 32/1000/season among term infants and 66/ 1000/season among preterm infants (P<0.001). Infants with predisposing conditions and/or nosocomial infection (n = 24) had significantly more severe courses than otherwise healthy infants (P<0.01). One-hundred thirty infants received respiratory support by nasal continuous positive airway pressure, but only six required mechanical ventilation. No infants died. CONCLUSION: The course of RSV disease in East Denmark was milder than reported elsewhere, possibly as a result of the low prevalence of bronchopulmonary dysplasia in Denmark. However, RSV constitutes a considerable burden to the Danish pediatric health care system, and therefore prophylaxis against RSV is desirable.

Denmark↗
PubMed1996

[Acute admissions in pediatric psychiatry].

This is a case study of 49 acute admissions to the Child Psychiatry Department at the Copenhagen County Hospital in Glostrup over the four year period 1.1.1990-31.12.1993. The aim is to appraise the concept of acute child psychiatric admission, examine the relation between definition and practice and evaluate the acute service and its viability. A retrospective analysis of the case notes shows that the 42 children involved constitute a selected group of mainly 11-14 years old girls, the most frequent diagnosis at referral- and at discharge-being anorexia nervosa. Most cases are referred from paediatric departments. Eighty percent of the acutely admitted children have had previous contact with one or more institutions. Time interval breakdown shows that more than a quarter of the cases were admitted some weeks after referral. The acute group had on average fewer hospital days than all other cases and only 12% were discharged without needing of further treatment. A further analysis revealed an inconsistency in terms of definition and practice. Only 39% of the patients were admitted within a 24-hour period after the acute referral, while 74% were admitted within the first week. The explanation is offered, that the definitions of and the indications for acute child psychiatric hospitalisation were loosely formulated and different from the more stringent medical terms and that some cases must be seen as being more of a subacute nature or representing clinical or social relapses. The question is raised whether the concept of acute admission in child psychiatric terms is viable.

Adolescent↗
PubMed1995

Oral ciprofloxacin versus intravenous cefuroxime as prophylaxis against postoperative infection in vascular surgery: a randomised double-blind, prospective multicentre study.

OBJECTIVES: To test the hypothesis that oral ciprofloxacin is equally effective as intravenous cefuroxime in preventing postoperative infectious complications in patients undergoing peripheral arterial surgery involving the groins. DESIGN: Prospective, randomised, double-blind multicentre study. MATERIALS: 580 patients undergoing arterial surgery involving the groins were randomised to ciprofloxacin (Ciproxin, Bayer) 750 mg x 2 p.o. or cefuroxime (Zinacef, Glaxo) 1.5 g x 3 i.v. given only on the day of surgery. The primary endpoint was wound/graft infection within 30 days postoperatively. Wound infection was defined as pus. RESULTS: The wound infection rate in the ciprofloxacin group was 9.2% (27 patients) and in the cefuroxime group 9.1% (26 patients) according to intention to treat. For correct treatment the corresponding numbers were 9.5% (23 patients) and 9.7% (22 patients), respectively. There were three graft infections (0.5%). The infection rate was 7.1% (31/433) in the absence and 14.9% (22/147) in the presence of distal ulcers (p < 0.05). S. allreus was the most common bacteria isolated. Forty percent of the wound infections were localised to the groins. By multivariate analysis presence of distal ulcer was the only factor of prognostic significance. CONCLUSIONS: The infection rate was similar in the two groups. Thus, oral administration of ciprofloxacin is an attractive, cost-effective and safe alternative to prophylaxis in vascular patients capable of taking oral medication on the day of surgery.

Administration, Oral↗
PubMed1994

[The social recruitment of medical students at Copenhagen University 1992/1993].

As part of a prospective survey of medical students' conditions and of the different kinds of influence they are subjected to during their study periods, we looked into the question of from which social strata the students were recruited. Two hundred and fifty-four (79%) of 323 medical students matriculated during the summer of 1992 answered a structured questionnaire forwarded to them. One hundred and thirty-one (52%) medical students were recruited from the highest social class (I), whereas only 19 (7%) were recruited from the lowest social class (V). In comparison, the underlying population in the age groups relevant for the survey is made up as follows: 7% in social class I and 20% in social class V. A comparison with earlier surveys shows that only insignificant changes in the medical students' social class profiles have taken place in spite of the introduction of better possibilities of financing medical studies irrespective of social class affiliations.

Adult↗
PubMed1994

Rehabilitation after amputation following lower limb fracture.

Twenty-two patients were interviewed after lower limb amputation above the ankle joint following fractures. Their median age at the time of the injury was 44 years (range, 14-77 years), and median amputation delay was 2 months (range, 0-213 months). Of the 15 patients who were working before the injury, ten returned to gainful employment after amputation. Amputation delay did not affect the ability to return to work. Twenty patients could walk outdoors; two patients aged 69 and 71 years could not, but regularly went outdoors using a wheelchair or a three-wheeled moped. Eleven patients were more or less dependent on help from others. The study indicates that most patients have an acceptable functional result, but with increasing age the chance of a return to employment decreases, and the need for help with everyday demands increases.

Activities of Daily Living↗