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Biomedical subjects

H Nielsen

Publications and source records attributed to H Nielsen.

At least 235 records · Page 13Linked to original sources
PubMed1990

Propafenone versus quinidine slow-release for the treatment of chronic ventricular arrhythmias.

The efficacy and side-effects of oral propafenone 300 mg b.i.d. were compared to those of quinidine slow-release 800 mg b.i.d. in a randomized double-blind placebo controlled cross-over study in 12 patients with symptomatic premature ventricular complexes (PVCs). Furthermore during steady-state the plasma levels of propafenone and quinidine were measured repeatedly over an 8-hour period and correlated to the numbers of PVCs. In 6 patients both drugs reduced PVCs by 80%. In 2 patients this effect was obtained by propafenone and not by quinidine, while the reverse was found in another 2 patients. In 2 patients neither of the drugs was able to reduce PVCs by 80%. During treatment with quinidine 4 patients experienced diarrhoea and 1 patient suffered headaches taking propafenone. The plasma levels showed great variation. No correlation between the plasma levels expressed as area under the concentration-time curve and the reduction of PVCs was found.

Adult↗
PubMed1990

[Carcinoma in situ of soft palate].

A case of carcinoma in situ in the soft palate in a 46-year-old man, heavy smoker, is presented. Six month's previously the patients own dentist discovered a rash in the soft palate, but no biopsy was taken until 6 months later when the patient was referred to the Dental Department, University Hospital, Copenhagen. The patient was referred to an oncologic department for evaluation. As radiation therapy was not indicated, surgery was performed. This included removal of the soft palate, tonsil and tonsil fossae. The patient had a palate plate done to relieve problems with swallowing. Patients with a long history of heavy smoking and oral lesions with suspicion for malignancy should always immediately after recognition of the lesion have more intensive examination and this should include a biopsy to establish a reliable diagnosis.

Carcinoma in Situ↗
PubMed1989

[Repetitive ventricular tachycardia. A type of arrhythmia with good prognosis].

Repetitive monomorphic ventricular tachycardia is usually considered a benign arrhythmia with a good prognosis in the absence of organic heart disease. However, the symptomatic course is variable. We report two cases, one of whom suffered slight symptoms only while the other was disabled by the arrhythmia in spite of treatment with numerous antiarrhythmic drugs including amiodarone. However, flecainid proved to be efficacious in this patient.

Adult↗
PubMed1989

Antitrophic properties of antihypertensive drugs may depend solely on their blood pressure-lowering capability. A comparative study of isradipine, hydralazine, and metoprolol.

The objective of this study was to examine the effect of antihypertensive treatment on the structure of intramyocardial resistance vessels in spontaneously hypertensive rats. The rats were divided into four groups: one was used as control and the other three were treated from the age of four to 24 weeks with isradipine, hydralazine, and metoprolol, respectively. Half of the animals in each group were examined at the end of active treatment and the rest were examined three weeks later. The rats were anesthetized and killed during constant flow perfusion with 1 percent glutaraldehyde. The media index was determined by point counting. The media indices of rats treated with isradipine and hydralazine were significantly smaller than those of age-matched spontaneously hypertensive rat controls, whereas the media indices of rats in the metoprolol group did not differ significantly. Three weeks after treatment withdrawal, the media index tended to increase in all three groups, but the values for the isradipine and hydralazine groups were still significantly reduced. Non-invasive blood pressure measurements taken at the same time demonstrated a significant blood pressure reduction in all groups, although differences within each treatment group were evident. All pressures had stabilized on the level of spontaneously hypertensive rats three weeks after withdrawal. Thus, it is evident that both isradipine and hydralazine were able to prevent hypertrophy of intramyocardial vascular structure and continue to do so even after treatment withdrawal. This finding is consistent with previous findings, suggesting a close relationship between the extent of blood pressure reduction and the degree of prevention of vascular hypertrophy.

Animals↗
PubMed1989

Sustained-release and instant-release verapamil in treatment of angina pectoris.

The efficacy of a sustained-release preparation of verapamil (verapamil-SR) has been compared with that of a conventional instant-release formulation (verapamil-IR) in 10 patients with stable angina pectoris treated for 3 weeks with both preparations. The diurnal serum concentrations of verapamil and norverapamil did not differ significantly during treatment with verapamil-IR 120 mg t.i.d. and verapamil-SR 360 mg once daily, but verapamil-SR 240 mg produced significantly lower serum concentrations. The differences did not affect the exercise capacity or the occurrence of ST-segment depression during maximal exercise. Verapamil-SR was well tolerated. A multiple instant-release dosage regime can now be replaced by once daily administration of the sustained-release preparation.

Angina Pectoris↗
PubMed1989

Fatal intramedular tumor of the cervical spinal cord during remission of acute lymphoblastic leukemia.

An adult male with acute lymphoblastic leukemia including meningeal leukemia was in complete clinical remission for more than one year after initiation of chemotherapy including intrathecally methotrexate and irradiation towards the brain and spinal cord. Signs of central nervous system involvement developed with symptoms primarily from the lower limbs and the urinary bladder but the cerebrospinal fluid was consistently without lymphoblasts. By magnetic resonance imaging an intramedular tumor of the cervical spinal cord was demonstrated and malignant cells compatible with lymphoblasts were obtained from the tumor at laminectomy. Despite immediate irradiation towards the tumor the patient died within two weeks.

Adolescent↗
PubMed1989

Interleukin 6 primes human neutrophil and monocyte oxidative burst response.

Interleukin 6 (IL-6), a 26-kDa inducible protein, is a cytokine with multiple biological activities. This paper reports on the regulatory role of rIL-6 on the function of human polymorphonuclear and mononuclear leukocytes, a property not described previously. rIL-6 by itself did not exhibit any chemotactic activity and it could not activate these cells for an oxidative burst response. Preincubation of both cell types with rIL-6 at concentrations of 5 and 50 ng/ml primed the cells for enhanced generation of oxygen radicals following stimulation with the chemotactic peptide f-Met-Leu-Phe or the phorbol ester PMA. The enhancement of the oxidative burst response occurred both at the level of superoxide anion generation, an early step in the activation pathway, and at the level of the hydrogen peroxide-myeloperoxidase mediated response, a later step in the oxidative burst pathway. The priming ability was abolished by heat treatment of rIL-6 at 100 degrees C but not at 70 degrees C. Stimulation of B cell growth and immunoglobulin production combined with enhancement of oxidative burst response of phagocytic cells by IL-6 provide an effective mechanism of fighting against invading micro-organisms.

Chemotaxis↗
PubMed1989

Pseudomonas aeruginosa exotoxin A primes human monocyte oxidative burst response in vitro.

Modulation of the oxidative burst responsiveness of human blood monocytes and neutrophils after incubation with purified exotoxin A from Pseudomonas aeruginosa was studied in a lucigenin- and luminol-enhanced chemiluminescence system. Exotoxin A alone caused a dose-dependent stimulation of monocyte chemiluminescence responses, whereas neutrophil responses were inconsistent. Preincubation of monocytes with exotoxin A primed the cells for a significantly higher oxidative burst response when N-f-methionyl-leucyl-phenylalanine (fMLP) was used as a secondary stimulus, especially in the lucigenin-enhanced system. Heat-treatment at 100 degrees C for 15 min completely abolished the priming activity of the exotoxin A preparation. These findings demonstrate that exotoxin A modulates monocyte responsiveness in the chemiluminescence assay and suggest that increased release of toxic oxygen radicals from mononuclear phagocytes may contribute to the tissue damage in lungs with chronic P. aeruginosa infections.

ADP Ribose Transferases↗
PubMed1989

Quantitative analysis of phospholipids and demonstration of plasmalogen in human neutrophil subcellular fractions by high-performance liquid chromatography.

The subcellular distribution of phospholipids in unstimulated neutrophils was investigated by high-performance liquid chromatography of lipid extracts of granule and plasma membranes obtained from Percoll density gradients. The mobile phase contained acetonitrile:methanol:85% phosphoric acid (131:3:0.8 v/v/v). Post-nuclear supernatants contained 2.3 micrograms lipid phosphorus/mg protein. Phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine were demonstrated in azurophil granules, specific granules and in a combined fraction of secretory granules and plasma membranes. Separate estimates of each phospholipid class by peak areas obtained by high-performance liquid chromatography showed that secretory granules and plasma membranes contained most of the phosphatidylinositol and phosphatidylcholine (p less than 0.005 vs peaks areas obtained in azurophil and specific granules), whereas a major part of the phosphatidylethanolamine was located in the specific granules (p less than 0.005 vs peak areas obtained in azurophil granules, and plasma membrane and secretory granules). High-performance liquid chromatography proved to be a useful principle for the demonstration of plasmalogen because the acidic solvent caused hydrolysis of phosphatidalethanolamine, which was recovered as lysophosphatidylethanolamine. Additionally, sphingomyelin was demonstrated in all subfractions by thin-layer chromatography.

Cell Membrane↗
PubMed1989

Preprandial blood glucose values: influence on glycemic response studies.

Through regressional analyses on data from two glycemic response studies, the influence of various preprandial blood glucose (PPBG) values upon glycemic response is highlighted. Repeated calculations on different subsamples of meals where the PPBG was below a given value showed that the influence of PPBG upon net glycemic response not was linear in the whole PPBG range. It was found that a PPBG less than 13 mmol/L had no influence upon net glycemic response whereas PPBGs greater than 13 mmol/L were significantly negatively correlated to the net glycemic response. To obtain more valid glycemic index figures we recommend that participants with PPBG greater than 13 mmol/L are excluded from glycemic response studies and that the number of participants are increased substantially.

Adult↗
PubMed1989

Normative data for eight neuropsychological tests based on a Danish sample.

Normative neuropsychological data have been provided using a sample of 101 persons aged 20 to 54 years. Eighty-seven of the subjects were recruited among patients who had undergone minor surgery, and 14 subjects were volunteers from the staff at the hospital laundry. The measures consisted of seven subjects from the WAIS-R, the trail-making test, symbol digit modalities test, auditory-verbal learning test, story recall test, visual gestalt test, recurring figures test, verbal fluency, and Purdue pegboard test. These measures were selected because of suitability in regard to time taken for testing each subject and their sensitivity to subtle changes in neuropsychological functioning. The sample was arbitrarily divided into three age groups, and for each of the three samples, mean, standard deviation, and range were calculated for each test. The results of the Information and Vocabulary subtests from the WAIS-R, education, and social status were applied as independent variables in linear regression analyses where each of the neuropsychological tests, in turn, was the dependent variable. For the oldest age group, age in addition was used as an independent variable. Significant linear relationships, which accounted for an optimal part of the variance, were selected for clinical application.

Adult↗
PubMed1989

Postjunctional alpha 2-adrenoceptors mediate vasoconstriction in human subcutaneous resistance vessels.

1. In vitro studies have been performed on human medium-sized muscular arteries (internal diameter 1-4 mm) in a classical organ bath and with human subcutaneous resistance arteries (internal diameter 103-626 microns) in a microvascular myograph. 2. Although the medium-sized muscular arteries showed no response to either of the alpha 2-agonists B-HT 933 or UK 14304 in concentrations up to 10 microM, the subcutaneous resistance arteries from all regions examined showed well-pronounced and concentration-dependent responses to B-HT 933, the pD2 (-log EC50) being 5.11 +/- 0.09. 3. In the resistance arteries the alpha 2-antagonist yohimbine caused a parallel shift to the right of the B-HT 933 concentration-response curve; the yohimbine pA2 for the B-HT 933 receptor was 7.86 +/- 0.12. 4. There was an inverse relationship between the maximum response to B-HT 933 and the calibre of the resistance vessels. 5. These results indicate the presence of a postjunctional alpha 2-adrenoceptor in human subcutaneous resistance arteries and not in medium sized muscular arteries.

Adult↗
PubMed1989

The effect of atrial natriuretic peptide on human isolated resistance arteries.

1. The action of (1-28) alpha-human atrial natriuretic peptide (ANP) was studied on human isolated resistance arteries. 2. Renal, skeletal muscle, omental and subcutaneous resistance arteries were taken from tissue removed at surgery and isometric tension responses were measured with a myograph. 3. ANP (10(-9)-10(-6) M) relaxed precontracted segments of renal and skeletal muscle arteries in a concentration-dependent manner. ANP failed to relax isolated omental or subcutaneous arteries. 4. The effect of ANP on human isolated resistance arteries varies depending on the site of origin of the artery.

Adult↗
PubMed1989

Leishmania interaction with human monocytes and neutrophils: modulation of the chemotactic response.

Infection of host cells with Leishmania, which are obligate parasites of mononuclear phagocytes, most probably involved chemotaxis of host cells towards the parasite. We have examined the chemotactic properties of a sonicate derived from L. mexicana amazonensis promastigotes for normal human peripheral blood monocytes and neutrophils. L. m. amazonensis sonicate exhibited chemotactic activity for monocytes and neutrophils. Treatment at 65 degrees C for 30 min, enhanced the activity for neutrophils but not for monocytes, while treatment at 100 degrees C for 60 min abolished the activity. Additional studies showed that the sonicate generated chemotactic activity in serum, presumably by activating the alternative complement pathway to produce C5a, for monocytes and neutrophils. Incubation of monocytes and neutrophils with the sonicate inhibited the chemotactic activity of these cells towards various chemoattractants. When the sonicate was heat-treated the inhibitory effect was lost, except when sonicate was used as a chemoattractant. These results indicate the presence of specific receptors for factor(s) from L. m. amazonensis promastigotes on human monocytes and neutrophils.

Animals↗
PubMed1989

Antibiotics and human monocyte function. II. Phagocytosis and oxidative metabolism.

The influence of thirteen commonly used antibacterial drugs on the phagocytic and oxidative burst responsiveness of human blood monocytes in vitro was investigated. Cefotaxime and rifampicin produced a significant inhibition of monocyte oxidative metabolism at therapeutic concentrations with increasing inhibition at higher concentrations. The effect of rifampicin was irreversible, which may reflect intracellular accumulation of the drug. Tetracycline, clindamycin, chloramphenicol and tobramycin at high concentrations produced a significant inhibition of monocyte superoxide anion release after stimulation, whereas normal therapeutic concentrations produced insignificant inhibition. Benzylpenicillin, ampicillin, fusidic acid, metronidazole, ofloxacin, sulfamethoxazole and trimethoprim did not alter monocyte oxidative metabolism in vitro. Phagocytosis of yeast cells was significantly suppressed by high concentrations of tobramycin, but otherwise unaffected by the drugs mentioned. These observations suggest that cefotaxime and rifampicin may interfere with blood monocyte oxidative metabolism in vivo, whereas it can be expected that at normal dosage it is unlikely that the other drugs will affect monocyte phagocytosis and oxidative burst activity.

Adult↗