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Biomedical subjects

T Nielsen

Publications and source records attributed to T Nielsen.

At least 37 records · Page 2Linked to original sources
PubMed2000

Influence of trace metals, acids and ethanol in food-simulating liquids on the retention of alpha-tocopherol in low-density polyethylene film.

The retention of alpha-tocopherol (vitamin E) in low-density polyethylene (LDPE) film was investigated when in contact with different food-simulating liquids. Variations of the aqueous food simulants approved by the EU for testing of interactions between packaging materials and food, and an alternative fatty food simulant (95% aqueous ethanol) were used to study the influence of trace metals and acids, as well as variation in pH and ethanol concentration, on the stability of alpha-tocopherol in the LDPE film. The presence of trace metals in aqueous media accelerated loss of alpha-tocopherol from the film, while the addition of citric or ascorbic acid counteracted this loss. In contact with aqueous ethanol at a concentration of 50% or higher, the loss of alpha-tocopherol from the film was total. However, with solutions containing less than 50% ethanol, the antioxidant was almost completely retained in the film, unless the temperature was increased from 6 to 40 degrees C. For contact with solutions containing ethanol or trace metals, an increase in temperature resulted in a greater loss of alpha-tocopherol from the LDPE film.

Acids↗
PubMed2000

Percutaneous transradial coronary angiography and angioplasty in patients with occlusive atherosclerotic iliofemoral disease.

Not all coronary angiograms can be acquired through the femoral route. The transradial catheterisation procedure in patients with occlusive atherosclerotic iliofemoral disease is described. Transfemoral left-sided cardiac catheterisation was performed in approximately 99.5% of patients referred for coronary angiography, while out of 48 patients in whom transfemoral access was impossible, transradial coronary angiography was successful in 37. With the exception of one, all patients with coronary artery disease had lesions of the right coronary artery, more than 70% had multivessel disease and 14% had stenosis of the left main coronary artery. Ten patients had angioplasty performed during the same procedure. Complications occurred in 5 out of 39 cases, 2 (5%) of these were severe. Although the femoral route was used in more than 99% of an unselected population referred for coronary angiography, it was found that transradial angiography and angioplasty can be performed in patients with occlusive atherosclerotic iliofemoral disease with considerable success and an acceptable complication rate.

Adult↗
PubMed2000

The incidence of potential conjunctival contamination in tonsillectomy.

A prospective study of 100 consecutive tonsillectomies was performed to assess the incidence of potential blood contamination of the surgeons' conjunctivae. Operating masks with plastic visors were used during these operations and examined by microscopy to detect blood contamination. 46% of visors were contaminated by blood. There was no significant difference with respect to how the operation was performed, or with the addition of adenoidectomy, but there was a significant difference between the rate of contamination between some surgeons. No surgeon performing more than three operations, however, escaped contamination. We recommend that eye protection be worn routinely in tonsillectomy.

Adult↗
PubMed1999

Calciphylaxis associated with metastatic breast carcinoma.

Calciphylaxis is a rare disorder associated with calcification of small- and medium-sized blood vessels, and progressive skin necrosis usually seen in the setting of end-stage renal disease (ESRD) and secondary hyperparathyroidism. It has also been observed in primary hyperparathyroidism, hypercalcemia of malignancy (extensive bony metastasis of breast cancer), and an isolated case reported with end-stage liver disease. We report an unusual case of calciphylaxis associated with metastatic breast carcinoma in the absence of renal or parathyroid disease. Calciphylaxis has generally been associated with end-stage renal disease and hyperparathyroidism. One previous case report described calciphylaxis occurring in a patient with metastatic adenocarcinoma of the breast and hypercalcemia. Our case represents the second reported case of calciphylaxis associated with osteolytic, metastatic breast cancer. Although ESRD with secondary hyperparathyroidism is the most common presentation of calciphylaxis, this case demonstrates that other conditions that alter normal calcium metabolism must be considered in the differential diagnosis.

Bone Neoplasms↗
PubMed1999

A controlled daytime challenge of motor performance and vigilance in sleep bruxers.

Many etiological factors have been suggested for sleep bruxism. Among these, elevated mental and physical alertness has been proposed to characterize sleep bruxers. The present study tests the hypothesis that, during the day-time, sleep bruxers are more vigilant and more prone to react to a motor command than are control subjects. Seven sleep bruxers, diagnosed polysomnographically according to validated research criteria, were matched for age and gender to seven control subjects. A simple reaction time task was selected to assess daytime vigilance and motor responsiveness. The following physiological measures were recorded: reaction time, error rate, electroencephalography, electrocardiography, electromyography, and video detection of body movements. Analysis of these variables showed no differences between groups. During the test, bruxers and controls showed a parallel decrease in EEG vigilance and heart rate over time. Frequency of orofacial and body movements was the same in both groups, and no clenching activity was observed during the experimental test. Subjects' visual analog scale ratings revealed that both controls and bruxers were more competitive after the test than before, and bruxers were slightly more anxious than controls before and after the test. Together, the results indicate that sleep bruxers are neither more vigilant nor more prone to react to a motor command during the daytime than are control subjects.

Adult↗
PubMed1999

Somnambulistic-like behaviour in patients attending a lithium clinic.

The prevalence of somnambulistic-like behaviour related to treatment with lithium alone or in combination with other psychotropic medications was evaluated in patients attending a lithium clinic. A written questionnaire on somnambulistic-like behaviour was completed by 389 patients. Information was provided on the time of occurrence, frequency and severity of the episodes, the presence of childhood somnambulism, and the temporal relationship between psychiatric treatment and somnambulistic-like behaviour. Twenty-seven (27) patients (6.9%) presented sleepwalking behaviour related to the onset of treatment with lithium alone or in combination with other psychotropic drugs. Forty-five patients (11.6%) reported childhood somnambulism and 12 of them (27%) had their childhood somnambulism reactivated by the medication. Most patients had a diagnosis of bipolar affective disorder but somnambulistic-like behaviour also occurred in patients with other axis 1 diagnosis. Sleep-related violence was seldomly reported. Therefore, lithium alone or in combination with other psychotropic drugs may induce somnambulistic-like behaviour. A history of childhood somnambulism may increase the risk of developing sleepwalking behaviour while under psychotropic drugs treatment.

Adult↗
PubMed1998

[Variations in hospital based psychiatric service between Aalborg and Aarhus. A registry-based 10-year investigation].

The study was based on data from the Danish Psychiatric Central Register. It consisted of 11,753 persons with permanent residence in the municipalities of Aalborg or Arhus, who had 32,557 admissions to a psychiatric hospital in Denmark during the period 1982-1991. The admission rates declined by 30%. The involuntary admission rate increased during the later years of the period, it was higher at the Psychiatric Hospital in Arhus (PHA). The bedday use per admission was 5.5 weeks on average at Aalborg Psychiatric Hospital (AAPH) and nine weeks on average at PHA. Through the period the bed rate (beds in use) was gradually reduced by 40%, most significantly at PHA. It can be concluded that the treatment at AAPH was less time-consuming. This is mainly caused by there being fewer beds available. Indices for quality of outcome did not give reason for conclusions in regard to differences in quality of treatment.

Adult↗
PubMed1998

The effect of tolcapone on levodopa pharmacokinetics is independent of levodopa/carbidopa formulation.

Clinical pharmacology studies have shown that the catechol-O-methyltransferase inhibitor tolcapone increases the bioavailability area under the plasma concentration-time curve (AUC) and the plasma elimination half-life (t1/2) of levodopa. The objective of the study was to evaluate the pharmacokinetics of levodopa and 3-O-methyldopa (3-OMD) after coadministration of tolcapone 200 mg with levodopa/ carbidopa in the following doses: 100/10 mg, 100/25 mg, 200/20 mg, 200/50 mg, 250/25 mg (all immediate-release) and 200/50 mg (controlled-release). Thirty healthy male volunteers were divided into four groups: three groups of 8 and one group of 6. Participants in the first three groups received two formulations of levodopa/carbidopa. Each dose was administered on two occasions, once with tolcapone 200 mg and once with placebo (four-way crossover). In the fourth group, one formulation was given on two occasions, once with tolcapone 200 mg and once with placebo (two-way crossover). Dosing days were separated by a 7-day washout. The effect of tolcapone on levodopa and 3-OMD pharmacokinetics was found to be similar with all levodopa/carbidopa formulations. The absorption of levodopa was unaffected by tolcapone in all treatment groups and the maximum plasma concentration (Cmax) remained unchanged. When tolcapone was given with the immediate-release formulations, levodopa AUC increased by 60-90% and levodopa t1/2 by 20-60%. With tolcapone and the controlled-release formulation, AUC increased by 80% and t1/2 by 60%. With all levodopa/carbidopa formulations, 3-OMD Cmax decreased by 80% and AUC by 70% with tolcapone. The tolerability of all treatment combinations was similar. We conclude that adjunctive treatment with tolcapone should have similar levodopa-potentiating clinical effects, regardless of the levodopa/carbidopa formulation.

Administration, Oral↗
PubMed1998

Clinical significance of intraplaque hemorrhage in carotid artery disease.

Previous research has indicated that intraplaque hemorrhage is a significant pathogenetic factor in carotid artery disease. The present study was undertaken to evaluate whether the clinical presentation of patients with carotid artery disease could be correlated to quantitative histologic analysis of surgically removed carotid specimens. Two-hundred-seventy patients undergoing carotid endarterectomy comprised the material. Symptomatology was assessed preoperatively. After removal, the carotid plaques were analyzed histologically for relative volume content of hemorrhage, fatty tissue, fibrous tissue, and calcification. There was no difference between asymptomatic and symptomatic patients. However, when the time interval between onset of symptoms and surgery was considered, plaques from patients with recent symptoms contained more hemorrhage compared with plaques from asymptomatic patients (p = 0.0045). The paper supports the theory of intraplaque hemorrhage being related to clinical events in carotid artery disease.

Adult↗
PubMed1998

Quality of life in chronic heart failure: cilazapril and captopril versus placebo. Cilazapril-Captopril Multicentre Group.

OBJECTIVE: To measure quality of life (QOL) in patients with mild to moderate heart failure treated with angiotensin converting enzyme (ACE) inhibitors cilazapril or captopril. DESIGN: Randomised, double blind, placebo controlled, parallel groups trial. SUBJECTS: 367 patients with New York Heart Association (NYHA) heart failure class II (62%), III (36%) or IV (1%). METHODS: Patients were randomised to receive cilazapril 1 mg daily (n = 191) or captopril 25 mg three times daily (n = 90) for 24 weeks, or placebo for 12 weeks followed by cilazapril 1 mg daily for a further 12 weeks (n = 86). If patients had not responded after four weeks cilazapril was increased to 2.5 mg daily and captopril to 50 mg three times daily. QOL was assessed at baseline, 12, and 24 weeks using the sickness impact profile (SIP), the profile of mood states (POMS), the Mahler index of dyspnoea-fatigue, and a health status index (HSI). RESULTS: The physical dimension of the SIP averaged 7 units at baseline and improved after 12 weeks by 2.24 units in the cilazapril group, 2.38 units in the captopril group, and 1.51 units in the placebo group. The difference between drug and placebo was therefore 0.73 units (95% CI -0.86 to 2.32) for cilazapril, and 0.87 units (95% CI -0.96 to 2.70) for captopril, with small non-significant effect sizes (a statistical method for estimating the importance of a treatment related change) of 0.12 and 0.14. Similar results were observed for the total POMS and HSI scores. Although QOL improved more on the ACE inhibitors than on placebo, the effect sizes were not significant (< or = 0.26). CONCLUSIONS: Improvements in QOL in mild to moderate heart failure were small when treated with cilazapril or captopril compared with placebo.

Adult↗
PubMed1998

Spectral analysis of wakefulness and REM sleep EEG in patients with sleep apnoea syndrome.

Neuropsychological investigations of patients with obstructive sleep apnoea syndrome (OSAS) have shown impairments in such basic functions as memory, attention and executive control. Since executive functions are known to be dependent on the integrity of the frontal lobe, it was hypothesized that OSAS may be associated with hypoxaemic frontal lobe dysfunction. To test this hypothesis, 21 apnoeic patients and 10 normal controls were studied with quantitative electroencephalographic (EEG) methods during rapid eye movement (REM) sleep, when most apnoeic events occur and during wakefulness. In apnoeic patients, EEG slowing in REM sleep was observed over frontal, central and parietal regions, while EEG slowing during wakefulness was observed over all cortical regions examined. A positive correlation was found between EEG slowing during wakefulness and oxygen desaturation during the night. Contrary to the hypothesis, these electroencephalographic changes were not localized only to the frontal region. This result may explain the wide range of neuropsychological deficits noted in patients with obstructive sleep apnoea syndrome, in addition to their poor performance in tasks of executive functioning.

Adult↗
PubMed1998

Interleukin-1alpha, interleukin-6 and interleukin-8 in cervico/vaginal secretion for screening of preterm birth in twin gestation.

BACKGROUND: The purpose was to determine the prognostic value of interleukin (IL) 1-alpha, IL-6 and IL-8 in cervico/vaginal secretion for preterm birth (<37 weeks of gestation) in twin pregnancies. METHODS: The study included screening of 121 women with twin pregnancies with sampling at 24, 26, 28, 30, 32 and 34 weeks of gestation. IL-1alpha, IL-6 and IL-8 was analyzed with ELISA immunoassays. The detection limit was 30 pg/mL for IL-1 and IL-8 and 40 pg/mL for IL-6. Vaginal fluid was smeared and dried for later evaluation of bacterial vaginosis (presence of clue cells). RESULTS: Spontaneous preterm birth occurred in 36 women and 65 women were delivered at term. IL-8 was significantly higher (p=0.03) in samples from women delivered preterm (median 3.72 ng/g mucus, range <0.07-220.00) compared with samples from women delivered at term (median 3.03 ng/g mucus, range <0.08-378.60). At 28 weeks of gestation, IL-8 (cut off 1.75 ng/g mucus) was associated with preterm delivery (relative risk 2.2, CI 95% 1.1-4.5) with a sensitivity, specificity, positive and negative predictive value of 78.8, 45.8, 44.8 and 79.4%, respectively. The levels of IL-1alpha and IL-6 were not significantly associated with preterm birth. Bacterial vaginosis was found in 47/541 (8.7%) samples analyzed. The levels of IL-1alpha and IL-8 were significantly higher in samples positive for bacterial vaginosis than in negative samples (p<0.0001 and p<0.01, respectively). There was no significant association between the level of IL-6 and bacterial vaginosis. CONCLUSIONS: IL-8, but not IL-1alpha and IL-6, was associated with preterm delivery but the relationship was too weak to be of predictive value for preterm birth in twin pregnancies. IL-1alpha and IL-8, but not IL-6, were associated with bacterial vaginosis.

Adult↗
PubMed1997

Differential DNA replication origin activities in human normal skin fibroblast and HeLa cell lines.

A modification of the extrusion method for the isolation of nascent DNA from mammalian cells and a PCR-based assay has been used in order to compare the in vivo activities of DNA replication origins in different cell lines. Conventional PCR was firstly applied to detect the chromosomal activities of several known (origins associated with c-myc, hsp70, beta-globin, immunoglobulin mu-chain enhancer) and putative DNA replication origins (autonomously replicating sequences obtained from enriched libraries of human origins of DNA replication from normal and transformed cells) in four human cell lines (HeLa, NSF, WI-38 and SK-MG-1). Then, in nascent DNA samples from normal skin fibroblast (NSF) and HeLa cells, abundance of DNA sequences in the regions of five of these origins was determined by competitive PCR. Our results suggest that autonomously replicating sequences NOA3, S14, S3 and F15 are associated with functional chromosomal origins of replication. Quantitative comparison of origin activities demonstrates that origins associated with c-myc and NOA3 are approximately twice as active in HeLa cells as in NSF cells. The described approach can facilitate the identification of origins which may be differentially active in normal cells and transformed cells or in different cell types.

Cell Line, Transformed↗
PubMed1997

Optimizing levodopa pharmacokinetics with multiple tolcapone doses in the elderly.

OBJECTIVES: The multiple-dose tolerability, pharmacokinetics, and pharmacodynamics of tolcapone, a novel catechol-O-methyltransferase (COMT) inhibitor, were assessed in healthy elderly volunteers receiving concomitant carbidopa and levodopa. METHODS: Thirty-six volunteers from 55 to 75 years old participated in this double-blind, placebo-controlled, ascending multiple-dose study. Tolcapone was studied at dosages of 100, 200, 400, or 800 mg three times daily (t.i.d.) in four sequential groups. Each group consisted of nine participants who had been randomized to receive either placebo (n = 3) or tolcapone (n = 6). Tolcapone or placebo was coadministered with carbidopa and levodopa (25 and 100 mg, respectively) for 7 days. Assessments included tolerability, pharmacokinetics of tolcapone, levodopa, and 3-O-methyldopa, and inhibition of COMT activity in erythrocytes. RESULTS: By inhibiting COMT, tolcapone reduced levodopa metabolism to 3-O-methyldopa, resulting in a twofold increase in levodopa exposure (area under the curve) and elimination half-life, without changing levodopa peak plasma concentration. These effects were similar on days 1 and 7 of treatment. Development of tolerance to COMT inhibition was not observed. Onset of effect was rapid (day 1 of treatment), and the maximum effect on levodopa pharmacokinetics was already observed with 100 or 200 mg tolcapone t.i.d. At these dosages, tolcapone pharmacokinetics were linear and stable; accumulation occurred with 800 mg t.i.d. The combination of tolcapone and carbidopa-levodopa was generally well tolerated, although more nausea and vomiting were observed at higher dosages (400 to 800 mg t.i.d.), particularly in women. CONCLUSION: Tolcapone shows promise as an effective adjunct to levodopa in the treatment of Parkinson's disease. Clinical pharmacology data indicate that the therapeutic regimen should be 100 or 200 mg t.i.d.

Administration, Oral↗
PubMed1997

Alexithymia and impoverished dream recall in asthmatic patients: evidence from self-report measures.

Early clinical impressions that alexithymia is associated with diminished dream recall have been supported by more recent research. The present study was designed to examine this association using self-report measures and a carefully screened clinical population. Thirty-three male and 43 female asthmatics from an outpatient clinic were administered the Toronto Alexithymia Scale, the Eysenck Personality Questionnaire, and a questionnaire concerning retrospective recall of dreams and nightmares. Multiple regression analyses revealed that, among men, dream recall was negatively related to alexithymia, especially to the TAS analytical mode of thinking subscale, independent of age and neuroticism. Among women, dream and nightmare recall were positively correlated with neuroticism. These results are consistent with early clinical observations of pensée opératoire, with some research findings, and with the notion that dream recall may be differentially associated with components of alexithymia in men and women patients.

Adolescent↗
PubMed1997

REM sleep dream mentation in right hemispherectomized patients.

Investigations of dream mentation in brain damaged patients have shed some light on the controversial issue of cerebral lateralization of dreaming. To examine further the relationships between brain function and dreaming, we studied REM sleep dream recall and content in four patients having undergone right functional or anatomical hemispherectomy and eight matched control subjects. Patients were found to have the capacity to report dreams to much the same extent as control subjects. Further, the patients' dream content was overall similar to that of the control subjects. The results provide strong evidence that dreaming is not a right-hemisphere function, and that the left hemisphere may be more critical for the generation of dreams. In addition, some characteristics of hemispherectomized patients' dream content (characters, smells) are consistent with the possibility that a history of epilepsy may influence REM sleep imagery over the long term.

Adolescent↗