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Biomedical subjects

C B Pedersen

Publications and source records attributed to C B Pedersen.

At least 19 recordsLinked to original sources

[The Cusum score. A tool for evaluation of clinical competence].

INTRODUCTION: The cusum analysis (cummulative summation) is a statistical technique used to assess the competence of medical trainees. We wanted to re-examine the validity of the test as a technique for qualitative assessment of competence, as well as a technique for monitoring the level of specialists' competence. METHODS: Doctors in two anaesthetic departments were asked to plot the cusum as they performed the following procedures: epidural and spinal analgesia, insertion of central venous and arterial cannulae. RESULTS: Data were collected over a year. Thirty-five doctors were asked to plot the cusum. The plots were returned by 75% (9/12) of the first year trainees, 50% (4/8) of the second- and third-year trainees, and 20% (1/5) of the four- and five-year trainees. From the specialists and consultants on the staff, we received 66% (4/6) and 50% (2/4). The correlation, according to the level of competence respecting spinal and epidural techniques, is shown in Figures 1 and 2. DISCUSSION: We found, that the cusum analysis is a valid and practical technique for the qualitative assessment of clinical competence as well as a tool for monitoring continuous professional development. The technique can be used in a number of settings. With the increasing demand in health care for continuous quality assurance, the analysis can be used both in personal professional monitoring and in monitoring of performance during training.

Anesthesia, Epidural↗

Cancer risk in a cohort of polio patients.

Poliomyelitis has hypothetically been associated with an increased risk of central nervous system (CNS) tumors. The present study was performed to examine not only the risk of CNS tumors but also the overall risk of cancer among a cohort of 5,883 polio patients. Patients diagnosed with acute poliomyelitis in the Danish capital, Copenhagen, between 1919 and 1954 were identified and followed with respect to cancer. Information on vital status and cancer diagnoses was obtained through linkage with the Danish Civil Registration System and the Danish Cancer Registry, respectively. The ratio of observed number of cancers to the number expected from population-based incidence rates, i.e., the standardized incidence ratio (SIR), served as measure of the relative cancer risk. Overall, 717 cases of cancer were observed among 5,883 polio patients during 249,084 person-years of follow-up vs. an expected number of 645 (SIR = 1.11 [95% confidence interval 1.03 to 1.20])). The increased risk was restricted to female polio patients (SIR = 1.18 [1.07 to 1.30]), among whom the risk was particularly high for breast cancer (SIR = 1.35 [1.12 to 1.61]) and for skin cancer (SIR = 1.66 [1.32 to 2.07]). The risk of breast cancer was highest among women with a history of paralytic polio (SIR = 1.62 [1.24 to 2.10]). The observed number of CNS tumors did not exceed the expected (SIR = 1.09 [0.72 to 1.60]). Women diagnosed with poliomyelitis, in particular paralytic polio, may be at increased risk of breast cancer. There was no association between malignancies of the CNS and poliomyelitis.

Age Factors↗

Risk factors and confounders in the geographical clustering of schizophrenia.

In response to previous reports of geographical clustering of individuals with psychosis, a study was carried out in Denmark utilizing the national case register. Two-thousand one-hundred and ninety-nine (2199) individuals with schizophrenia were divided by place of birth into 217 geographical areas and analyzed by age, gender, month of birth, genetic relatedness, and degree of urbanization of birthplace. Heterogeneity was ascertained using log-linear Poisson regression. The greatest amount of heterogeneity was associated with degree of urbanization of place of birth. Heterogeneity was also associated with age-gender interaction and calendar period. When adjusted for these factors, there was no remaining heterogeneity, suggesting that all geographical clustering in our study was explained by the above factors.

Cluster Analysis↗

[Ear implantations].

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Cochlear Implantation↗

The role of chaperone-assisted folding and quality control in inborn errors of metabolism: protein folding disorders.

Molecular chaperones are present in the various compartments of the cell and assist the folding of newly synthesized proteins. Compared to wild-type proteins, missense mutant proteins are generally synthesized in a normal fashion, but may be impaired in their folding. A broad array of diseases that are due to misfolding of mutant proteins may be labelled conformational diseases: aggregation diseases, such as Alzheimer disease; diseases caused by negative dominance from misfolded structural proteins, such as hypertrophic cardiomyopathy; and disorders where the misfolded protein is degraded by intracellular proteases. Many metabolic disorders belong to this last category, where the so-called protein quality control systems, comprising chaperones and proteases, attempt to eliminate folding intermediates or misfolded proteins. On the basis of in vitro experiments with a limited number of missense mutations identified in patients with phenylalanine hydroxylase and fatty acid oxidation deficiencies, we discuss the cellular fate of missense mutant proteins. We find that the balance between folding to functional conformers, retention (holding) and degradation of folding intermediates or misfolded proteins is dependent on the nature of the mutation and on the efficiency of the quality control. For example, low temperature may promote formation of functional conformers, while elevated temperature usually promotes retention and degradation. We conclude that disorders caused by many missense mutations are complex diseases in which the mutation itself is a necessary major primary component, but that its effect may be modified by cellular conditions and possibly by genetic variations in the quality control systems. We suggest that this new knowledge about cell handling may open new avenues of understanding of the cell pathology and treatment of patients with metabolic disorders.

Animals↗

How does endotoxin trigger inflammation in otitis media with effusion?

OBJECTIVES: The relationship among microorganisms, endotoxin, and inflammatory mediators in otitis media with effusion (OME) was examined. STUDY DESIGN: Analysis of 152 middle ear effusions aspirated at the time of ventilation tube insertion from children with OME. METHODS: Effusion samples were cultured for pathogenic bacteria The two primary cytokines, interleukin-1beta (IL1beta) and tumor necrosis factor (TNFalpha), and the adhesion molecules, intercellular and vascular adhesion molecule (ICAM-1 and VCAM-1), were quantified using the enzyme-linked immunosorbent assay (ELISA) technique. Endotoxin concentration was measured with a limulus amebocyte lysate assay, and total protein concentration was quantified using the Biorad microassay. RESULTS: The cultures of pathogenic bacteria were positive in 33 of the 152 effusions (22%), which contained more endotoxin and more of the primary cytokines than the 119 culture-negative effusions. Endotoxin and the primary cytokines were positively correlated, both in the whole material and in the sterile effusions alone. The adhesion molecules were positively correlated with each other, but not with endotoxin or the primary cytokines. CONCLUSIONS: We found a positive correlation between endotoxin and the primary cytokines TNFalpha and IL1beta in culture-positive OME effusions as well as in culture-negative ones, suggesting endotoxin-induced local production of TNFalpha and IL1beta in the middle ear. ICAM-1 and VCAM-1 were also present in the middle ear, but their concentrations were not directly correlated to endotoxin or the primary cytokines.

Bacterial Infections↗

Family history, place and season of birth as risk factors for schizophrenia in Denmark: a replication and reanalysis.

BACKGROUND: Although a family history of schizophrenia is the strongest individual risk factor for schizophrenia, environmental factors related to urbanicity may contribute to a substantial proportion of the population occurrence of the disease. AIMS: This study replicates previous findings in four mutually exclusive Danish study populations, including out-patient information, ICD-10 diagnoses of schizophrenia, and a broader adjustment for mental illness in family members. METHOD: We established a population-based cohort of 2.66 million Danish people using data from the Civil Registration System linked with the Psychiatric Case Register. RESULTS: Overall, 10 264 persons developed schizophrenia during the 50.7 million person-years of follow-up. The risk of schizophrenia was increased by urbanicity of place of birth and by family history of schizophrenia or other mental disorders. CONCLUSIONS: Urban-rural differences of schizophrenia risk were replicated and could not be associated with the potential sources of bias we assessed. Environmental factors underlying the effect of place of birth are major determinants of schizophrenia occurrence at the population level, although the effect of family history is the strongest at the individual level.

Adolescent↗

[Results and experiences with 55 cochlear implantations].

INTRODUCTION: The etiology of deafness in deaf people is defects in the cochlea hair cells. Cochlear implant treatment gives deaf born and patients with acquired deafness the possibility to reestablish or obtain hearing by electric stimulation of the cochlear nerve. In this paper the results of treatment of 35 adults and 20 children are reported. METHOD: The candidates for cochlear implant treatment are extensively investigated before the decision is made to operate. The operative treatment takes place under general anaesthesia and the operative technique is outlined. In the treatment of the deaf, different types of implants and stimulation strategies have been used. The effect of treatment is considered by hearing test and evaluation of speech. RESULTS: Nine of the adults obtained a hearing quality that made using a telephone possible. Almost all adults can by the combination of cochlear implant and lip reading perform a normal conversation. The results in the deaf born children are obtained slowly as the deaf born have to develop hearing and speech from zero. All the treated children have improved possibilities of communication. DISCUSSION: Cochlear implant treatment of deaf people now seems well established both internationally and nationally in Denmark. Cochlear implant equipment has improved considerably throughout the past years and that it today is possible to establish hearing in deaf born or patients with acquired deafness can be considered as one of the greatest developments in otology, maybe the greatest.

Adolescent↗

[Treatment of tinnitus with low-intensity laser].

UNLABELLED: This study evaluated the effect of low-power laser in the treatment of tinnitus in a randomized, prospective, double-blind, placebo-controlled trial. The active laser applied 50 mW (cw, 830 nm) over a period of 10 minutes per session. Forty-nine patients were included. The main outcome was measured using psychoacoustical match of tinnitus loudness, Visual Analog Scale (VAS) ratings of subjective loudness, annoyance and attention involved, scores on tinnitus-specific questionnaires, and a number of psychosocial questionnaires. Only few subjects (18%) experienced subjective improvement. There were no statistically significant differences between the effects of the active laser and placebo treatments. CONCLUSION: Low-power laser treatment is not indicated in the treatment of tinnitus. Reports of significant benefits of this treatment in previous studies may be explained by the placebo effect.

Adult↗

[Meniere's disease. The clinical effect of gentamicin treatment].

In patients with Menière's disease attacks of vertigo can be invalidating. We have tested the effect of instillation of gentamycin in the middle ear to minimize or stop the attacks of vertigo. The results of a prospective investigation of 14 patients with Menière's disease treated with gentamycin in the period from 1993 to 1996 are presented. The patients were followed up to 53 months after the treatment and a telephone follow-up was performed. At the last follow-up nine out of 12 patients were free of attacks of vertigo. Two improved and one patient was unchanged. In two patients deafness developed in the treated ear, in the other patients the hearing was unchanged measured by speech reception threshold and discrimination loss. It is concluded that treatment of patients with Menière's disease by instillation of gentamycin into the middle ear does have a therapeutic effect. The treatment is simple and the effect of treatment is equal to other types of treatments. The risk of deafness in the treated ears stresses the importance of giving the patient sufficient information before treatment.

Administration, Topical↗

Pseudoaneurysm of a lateral internal carotid artery in the middle ear.

We report a case where a 7-year-old girl suffered significant aural bleeding following myringotomy of the tympanic membrane. Investigations by computed tomography scan, carotid angiography, and magnetic resonance angiography showed a lateral aberrant internal carotid artery (LACI) with a little pseudoaneurysm in the middle ear. The anomaly of the internal carotid artery was supposed to be congenital, and the pseudoaneurysm was supposed to be traumatic, formed after incision into the wall of the artery. Considerations about diagnosis, symptoms, and treatment are discussed. The patient was treated by balloon embolization in the internal carotid artery without sequelae.

Aneurysm, False↗

Functional brain imaging of tinnitus-like perception induced by aversive auditory stimuli.

Tinnitus is an aversive auditory percept of unknown origin. We tested the speculation that tinnitus may share neuronal processing mechanisms with aversive auditory percepts of known origin. This study revealed the functional neuroanatomy of the perception of aversive auditory stimuli. The stimuli were presented to 12 healthy volunteers so as to mimic the psychoacoustical features of tinnitus and its affective response in tinnitus sufferers. The regional cerebral blood flow distribution was measured by PET during four auditory processing conditions and one control condition. The aversive auditory stimuli activated primary and secondary auditory areas bilaterally, dorsolateral prefrontal attention areas, and structures in the limbic system which subserve emotional processing. Based on these results and findings from other functional neuroimages of tinnitus, we hypothesize that the perception of tinnitus may involve the functional linkage of these brain areas: secondary auditory cortex, dorsolateral prefrontal cortex, and limbic system.

Acoustic Stimulation↗

Effects of blueberry and cranberry juice consumption on the plasma antioxidant capacity of healthy female volunteers.

OBJECTIVE: To assess whether consumption of 500 ml of blueberry juice or cranberry juice by healthy female subjects increased plasma phenolic content and antioxidant capacity. DESIGN: Latin square arrangement to eliminate ordering effects. After an overnight fast, nine volunteers consumed 500 ml of blueberry juice, cranberry juice or a sucrose solution (control); each volunteer participated on three occasions one week apart, consuming one of the beverages each time. Blood samples were obtained by venipuncture at intervals up to four hours after consumption of the juices. Urine samples were also obtained four hours after consuming the juice. RESULTS: Consumption of cranberry juice resulted in a significant increase in the ability of plasma to reduce potassium nitrosodisulphonate and Fe(III)-2,4, 6-Tri(2-pyridyl)-s-triazine, these measures of antioxidant capacity attaining a maximum after 60-120 min. This corresponded to a 30% increase in vitamin C and a small but significant increase in total phenols in plasma. Consumption of blueberry juice had no such effects. CONCLUSION: The increase in plasma antioxidant capacity following consumption of cranberry juice could mainly be accounted for by an increase in vitamin C rather than phenolics. This also accounted for the lack of an effect of the phenolic-rich but vitamin C-low blueberry juice. SPONSORSHIP: Funded by the Scottish Executive Rural Affairs Department and the Danish Government.

Adult↗

Incidence and growth pattern of vestibular schwannomas in a Danish county, 1977-98.

During a period of 21 years 162 acoustic neuromas or vestibular schwannomas (VS) were diagnosed in the county of Aarhus. During this period the incidence increased gradually, probably due to improvement of the quality of computed tomography imaging (CTI), and more widely available access to magnetic resonance imaging (MRI). Sixty-four patients were followed up by repeated CTI or MRI, whereas the remaining patients were referred for immediate operation. Six of the observed patients had their tumours removed after demonstration of continuous tumour growth. The observation of 64 tumours over periods between 5 months and 15 years provided useful information on the natural history of sporadic VS. Our results showed that 14 VS (22%) regressed, 35 VS (55%) did not grow or had only minimal growth (growth rate up to 1 mm/year), whereas 15 VS (23%) grew > 1 mm/year. All VS with positive growth had regular growth patterns.

Adult↗

Middle ear epithelium has inflammatory capacity.

Endotoxin, tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and intercellular adhesion molecule-1 (ICAM-1) were detected in 88%, 51%, 58% and 66% of 152 middle ears from patients suffering from otitis media with effusion. In this study the hypothesis that bacterial endotoxin, TNF-alpha, IL-1 beta and ICAM-1 induce the inflammatory process characteristic of otitis media with effusion was tested. Cultures of rabbit middle ear epithelium were exposed to endotoxin, TNF-alpha or IL-1 beta. The expression of ICAM-1 on the cell surfaces was measured with a direct enzyme-linked immunosorbent assay on the cell layer. For TNF-alpha, 5 ng/ml significantly increased ICAM-1 expression, whereas 100 ng/ml had a toxic effect. For IL-1 beta, as little as 1 ng/ml produced a significant increase in ICAM-1 expression. Endotoxin stimulated ICAM-1 expression less strongly in concentrations from 100 ng/ml to 100 micrograms/ml. The findings indicate that stimulation of ICAM-1 by endotoxin is mediated, at least in part, by TNF-alpha and IL-1 beta. It is concluded that endotoxin induces sustained inflammation in OME, and that this inflammation is mediated, at least in part, by the primary cytokines TNF-alpha and IL-1 beta.

Animals↗

Acute mastoidectomy in a Danish county from 1977 to 1997--operative findings and long-term results.

Data from patients undergoing acute mastoidectomy were examined retrospectively to evaluate if the nature of acute mastoiditis (AM) treated surgically has changed during the last 20 years (1977-97). Moreover, a prevalence study was conducted to clarify the otological and audiological course following acute mastoidectomy. Patients with cholesteatoma and intracranial complications were excluded. Thus, 79 patients with a median age of 16 months were included. Thirty-seven percent had a history of middle ear disease, and the mean duration from onset of symptoms to admission was 9 days. Well-being was affected in 46%, and 82% had fever. The clinical picture was dominated by auricular protrusion (77%) and pathological tympanic membrane (94%). Postauricular oedema, hyperaemia and tenderness were demonstrated in 89%, 78% and 49% of cases, respectively. Peroperatively, purulent middle ear effusion was recognized in 92%, subperiosteal abscess in 66% and pus in the mastoid in 90%. Specimens revealed growth of pathogens in 58%, predominantly Gram-positive bacteria. The observation period was 1-20 years. The findings in operated ears were not significantly different from the contralateral non-operated ears concerning incidence of otitis media, hearing and ear canal volume. Conclusively, acute mastoidectomy is a safe and effective treatment to eliminate infection. The operation can be done with negligible risk and does not leave long-term sequelae.

Acute Disease↗

Results and experience of 50 cochlear implant operations.

Cochlear implantation (CI) is a relatively new type of treatment that aims to re-establish hearing in deaf people. This paper reports on the results from CI operations on 34 adults and 17 children. All patients benefited from the treatment. The adults' communication with other people improved. Almost all patients use their implant 16 h a day and some of them are able to communicate by telephone. Among children the results show that the treatment is safe, as no complications have developed. Hearing and speech improved in all children, and thus also their ability to communicate. The results obtained are dependent on the individual patient's condition, the time of operation in relation to the development of deafness, and the type of CI used. CI treatment of deaf people may be considered to be one of the greatest advances in otology.

Adolescent↗