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Biomedical subjects

H Nielsen

Publications and source records attributed to H Nielsen.

At least 271 records · Page 15Linked to original sources
PubMed1988

Size and site-dependent heterogeneity of human vascular responses in vitro.

Ring segments of splanchnic, peripheral, coronary, pulmonary and uterine conduit arteries obtained during surgery were studied in tissue baths. Resistance arteries dissected from various sites were studied in a myograph. Both conduit and resistance vessels contracted in response to the alpha 1-agonist phenylephrine (10(-7) to 10(-4) mol/l), an effect that was antagonized by the alpha 1-antagonist doxazosin (10(-8) to 10(-6) mol/l). However, the alpha 2-agonists BHT 933 (10(-7) to 10(-4) mol/l) and UK 14304 (10(-7) to 10(-4) mol/l) only contracted the resistance vessels and not the conduit arteries. The response to BHT 933 was competitively antagonized by the alpha 2-antagonist yohimbine (3.10(-8) to 3.10(-7) mol/l) and the magnitude of the contractile response was inversely related to vessel size. Similarly, neuropeptide Y (10(-9) to 10(-6) mol/l) contracted only the resistance vessels, and induced marked tachyphylaxis. Atrial natriuretic peptide (ANP; 10(-8) to 10(-6) mol/l) produced concentration-dependent relaxation in all conduit arteries studied, being ineffective in resistance arteries from subcutaneous or omental sites, but relaxed those from renal tissue and skeletal muscle. Calcitonin gene-related peptide (10(-8) to 10(-6) mol/l) and vasoactive intestinal peptide (10(-9) to 10(-6) mol/l) relaxed both conduit and resistance arteries. This response was dependent on the integrity of the endothelium in the systemic conduit but not the resistance vessels. These results indicate that the receptors for adrenergic agonists and vasoactive peptides are varyingly distributed throughout the human vasculature.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteries↗
PubMed1988

Procedures in evaluating dementia--a study of conjoint application of two rating scales (SCAG and BCRS) and psychometric tests.

Fifty-seven patients with dementia (mean age 74 years) were treated for 16 weeks with 2 different doses of a test drug or placebo. On day 0 no significant differences (Kruskal-Wallis H test) were found between the 3 treatment groups on psychometric test scores or the total scores on 3 rating scales (Modified Crichton Geriatric Behaviour Rating Scale, Sandoz Clinical Assessment - Geriatric (SCAG) scale and Brief Cognitive Rating Scale (BCRS). The score differences (the total scores on day 112 minus the total scores on day 0) on SCAG, BCRS and psychometric tests were subjected to a series of one-way analyses of variance. As no significant difference was found between the groups, they were combined into a single group. In this group the relationship between total scores on SCAG and BCRS and psychometric test scores was analysed. Setwise multiple regression analyses (with the psychometric test scores as the independent variables) showed that at most 34% and 45% (respectively) of the variance in the SCAG ratings was accounted for by the results from a small subgroup of tests (dealing with visuo-motor speed and verbal memory) on day 0 and day 112. The results of a somewhat bigger subgroup of tests (dealing with visuo-motor speed, verbal memory and general intelligence) explained 58% of the variance in the BCRS ratings both on day 0 and after 16 weeks. Canonical correlation analysis using scores on the 2 rating scales and the psychometric test results was applied complementarily to make the inferences as valid as possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Crystalline inclusions in epithelial cells of hairy leukoplakia: a new ultrastructural finding.

Hairy leukoplakia is often the first manifestation of an HIV infection. In the present study we have investigated the ultrastructural features of hairy leukoplakia in two HIV seropositive male homosexual patients. Ultrastructurally EBV particles were found in the upper prickle and keratinized epithelial cells, whereas papilloma virus particles were not found. Candida albicans were also seen in the keratinized layer. In addition two types of inclusions which have not previously been reported in hairy leukoplakia were commonly seen in the epithelial cells containing the EBV. The first was a crystalline microtubular structure which may take the form of several arrays. The second was an elongated multivesicular structure consisting of membrane-bound rounded vesicles embedded in a background of fine filaments. The vesicles were similar to the empty looking EBV particles and their mean diameter was 100 nm. Further investigations are needed to elucidate the exact nature of these structures and their relationship to the Epstein-Barr virus.

Cell Nucleus↗
PubMed1988

Effect of oral N-acetylcysteine administration on human blood neutrophil and monocyte function.

N-acetylcysteine (NAC) is known to be a scavenger of free oxygen radicals, and recent in vitro studies have demonstrated that it is also able to inhibit leukocyte function. The clinical significance of these effects is, however, not known. In this study we have measured the effect on human blood neutrophil and monocyte function of a single 400 mg dose of NAC administered orally. Administration of NAC to ten healthy volunteers resulted in significant reduction of neutrophil chemiluminescence response following activation by opsonized zymosan as compared to four non-treated persons acting as controls. No effect was observed on the chemotaxis of either cell type or on monocyte chemiluminescence response. These findings suggest that NAC may be beneficial in clinical conditions like cystic fibrosis, where tissue damage may be a consequence of the effects of increased release of toxic oxygen radicals and proteolytic enzymes.

Acetylcysteine↗
PubMed1988

Blood-monocyte functions in acute bacterial meningitis.

The blood-monocyte chemotactic, phagocytic and microbicidal activities were studied in 20 patients with acute bacterial meningitis. The cell functions were measured on admission, during treatment and after clinical recovery. In general, monocyte functions were within normal range on admission. However, in 2/2 patients with Neisseria meningitidis meningitis, complicated by disseminated intravascular coagulation, defective chemotaxis was observed. Other patients had normal or enhanced monocyte chemotaxis. Two patients died: one had normal monocyte functions, one had initially defective chemotaxis and microbicidal activity. During treatment, cell functions normalized and after recovery all but one patient had a normal blood-monocyte function profile. In conclusion, acute bacterial meningitis is not due to, or followed by, abnormal nonspecific functions of blood monocytes. However, development of disseminated intravascular coagulation is associated with depressed chemotactic responsiveness.

Acute Disease↗
PubMed1988

Analgesic effect and bioavailability of oral ketogan given as tablets or mixture to patients with chronic pain of malignant origin.

Thirteen cancer patients with moderate to severe chronic pain of malignant origin on treatment with Ketogan tablets were included in an open non-randomized cross-over study comparing the analgesic effect, side effects and serum concentrations of Ketogan tablets and mixture. The patients were six days in hospital and were dosed two days with tablets, two days with mixture and finally another two days with tablets. Recordings of pain and side effects and collection of blood samples prior to dosing and hourly thereafter until remedication were performed on the second day of each dosing period in a morning dose interval. The analgesic effect judged by visual analog score (VAS) and pain intensity differences (PID), the areas under the serum concentration time curves, and the average serum concentrations for the three groups were compared. It was not possible do detect any differences among the three groups concerning the analgesic effect, duration of analgesic effect, the serum concentrations and the side effects. The mean plasma half-life of ketobemidone was 2.74 h +/- 0.90 (SD) and the mean relative bioavailability of the mixture was slightly above 100%. Linear regression analysis revealed a significant correlation between ketobemidone serum concentrations and analgesic effect, VAS, for tablet one and for the mixture but not for tablet two, possibly due to the fixed dosing schedule and to the positive effect of hospitalization on the pain.

Administration, Oral↗
PubMed1988

Long-term hypotensive effects of an angiotensin converting enzyme inhibitor in spontaneously hypertensive rats: is there a role for vascular structure?

Male spontaneously hypertensive rats (SHR) were treated from 4 to 24 weeks of age with perindopril, an angiotensin converting enzyme (ACE) inhibitor, in doses of 0.4 and 0.8 mg/kg per day; we investigated the effects of these doses on blood pressure during and after withdrawal of treatment, and on the structural and functional characteristics of the resistance vessels. During treatment, mean blood pressure was maintained close to the level of normotensive control Wistar-Kyoto rats (WKY). At the age of 24 weeks, a resistance vessel segment was taken as a biopsy from the third branch of the superior mesenteric artery, and the structural and functional parameters were determined using an isometric myograph. Taken together with previous results the measurements showed that perindopril had a dose-dependent effect on both blood pressure and resistance vessel media thickness. Treatment was then withdrawn. Twelve weeks later, the mean blood pressure in both groups was still significantly reduced compared to that of age-matched SHR controls, but was no longer dose-related, nor was it related to the resistance vessel media thickness at age 24 weeks. The results suggest that the continuing reduction in blood pressure after withdrawal of treatment with perindopril may not be directly related to the drug's effect on resistance vessel structure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1987

Complement C3b receptors on erythrocytes in patients with juvenile rheumatoid arthritis.

Forty patients with juvenile rheumatoid arthritis (JRA) were examined for C3b receptor (CR1) levels on erythrocytes (by an enzyme-linked immunosorbent assay), levels of circulating immune complexes (IC) (by a polyethylene glycol precipitation-complement consumption method), C3d split products (by intermediate gel rocket immunoelectrophoresis), and HLA-A, B, and C (by microdroplet lymphocytotoxicity test). Lower CR1 levels were found predominantly among patients with JRA (mean 57%) compared with 40 age-matched controls (mean 68%) (P = 0.008). The CR1 levels differed when the JRA patients were grouped by mode of disease onset and by clinical state at the time of testing (levels in patients with pauciarticular disease were higher than those in patients with polyarticular disease, and levels in patients with polyarticular disease were higher than those in patients with systemic disease) or by sex (girls had higher levels than boys; P = 0.01). The levels of circulating IC and C3d were elevated in 25% and 40% of JRA patients, respectively, and were mutually correlated (P less than 0.05, tau = 0.20). A negative correlation was found between levels of C3d and the numbers of CR1 (P less than 0.01, tau = -0.28), but concentrations of circulating IC did not correlate with CR1 values. CR1 levels were the same in 6 HLA-B27 positive and 25 HLA-B27 negative patients. These findings do not represent conclusive evidence that the number of CR1 on erythrocytes serves as a predictor of disease severity or as an indicator of disease activity in patients with JRA.

Adolescent↗
PubMed1987

Defective monocyte oxidative metabolism in a child with non-pneumonic legionellosis.

A case of non-pneumonic legionellosis with gastrointestinal manifestations is described in a 13-year-old boy without premorbidity. A selective defect in monocyte oxidative metabolism was found and consistently demonstrated throughout the following year. We suggest that the observed monocyte deficiency may have facilitated the development of legionnaires disease and that otherwise normal monocyte function may have contributed to the favourable course of disease.

Adolescent↗
PubMed1987

Modulation of human neutrophil and monocyte oxidative burst by Legionella pneumophila sonic extract.

The effect of Legionella pneumophila sonic extract on human neutrophil and monocyte oxidative burst was studied by superoxide anion release and luminol-enhanced chemiluminescence assays. Legionella pneumophila sonic extract by itself did not stimulate neutrophils and monocytes. The sonic extract at 8-2000 micrograms/ml primed neutrophils for enhanced superoxide release and, at 8-62.5 micrograms/ml, for enhanced chemiluminescence. Monocytes were only primed for enhanced chemiluminescence at very low extract concentrations (below 16 micrograms/ml). Monocyte superoxide release was suppressed by extract concentrations higher than 2000 micrograms/ml and the chemiluminescence response of neutrophils and monocytes by concentrations higher than 250 and 125 micrograms/ml, respectively. The priming activity was heat stable and present in fractions below 5 kDa. On the basis of these findings it is suggested that enhanced production of oxygen metabolites by neutrophils in contact with legionella components at low concentrations could contribute to the lung tissue damage seen in Legionnaires' disease, whereas the suppression of phagocyte oxidative burst by higher extract concentrations may be one of the mechanisms by which Legionella pneumophila survives intracellularly.

Endotoxins↗