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Biomedical subjects

H Nielsen

Publications and source records attributed to H Nielsen.

At least 433 records · Page 24Linked to original sources
PubMed1978

Bacterial contamination of anaesthetic gases.

The bacterial content of oxygen and nitrous oxide immediately before and after passing through clean and used breathing systems (circuits) was measured using a specially constructed agar chamber (Bourdillon's slit sampler). The content per litre of oxygen from the outlet of the anaesthetic machine was 4.0 X 10-2, and 2.9 X 10-2 for nitrous oxide, corresponding to 3.5 X 10-2 for a 50% mixture of the gases. After passing through cleaned circuits, the bacterial pollution of the gas mixture had increased by 30%, but more than elevenfold after passing through used circuits. The content from cleaned circuits was less than that measured previously in the air of hospital wards and operating theatres, whereas gases from used circuits were polluted to approximately the same extent. It is concluded that used circuits may increase the risk of cross-infection. The cleaning method employed by us (dish-washer--hot airy drying) appeared to be acceptable.

Anesthesia, Inhalation↗
PubMed1978

Thyroglobulin of varying molecular sizes with different disappearance rates in plasma following subtotal thyroidectomy.

To investigate the possible presence of thyroglobulin (Tg of different molecular sizes in plasma, blood specimens were drawn from patients during and after surgery for thyroid adenoma. Tg was measured in all serum samples by a radioimmunoassay. Selected samples were fractionated on a sepharose CL-6B column, and the fractions were assayed for Tg antigen. In serum drawn at maximum Tg concentration, molecular weights of Tg antigen ranging from 660,000 (19S) to less than 100,000 were found. 6 h later the Tg antigen of mol. wt. less than 100,000 could not be detected, and after 3 days only 19S Tg was present. Correspondingly the plasma Tg concentration vs. time curve showed a biphasic course from which two half-lives could be estimated. For 19S Tg, ta1/2 had a mean value of 4.3 days, whereas the over-all half-life for the mixture of smaller molecules, tb1/2, had a mean value of 3.7 h. The smaller molecules also showed different antigenic reactivity in the assay indicating an altered structure of the molecules. The assumption that this might be due to lack of sialic acid would explain the faster catabolic rate.

Antigens↗
PubMed1978

Circulating immune complexes, complement activation kinetics and serum sickness following treatment with heterologous anti-snake venom globulin.

Consecutive serum and plasma samples, from a patient receiving 100 ml polyvalent horse anti-venom globulin after a rattlesnake bite, were analysed for circulating immune complexes (IC) and activation of complement factors. IC were determined by two independent methods, a complement consumption assay and a Clq-binding assay. Rapidly rising levels of complement-fixing circulating IC were detected as early as 4--5 days after the serum treatment and distinct IC-activity was recorded in both assays on day 8 when clinical symptoms of serum sickness were observed. The IC remained in circulation for at least 5 weeks. Signs of intravascular C-activation in the form of low C3, C4 and C5 values was noted on day 1 after treatment. Factor B was demonstrable 3--4 days after the snake bite and this factor and C3c attained a peak around day 8, just before maximal suppression of native C3 and C4. 14 days after the globulin treatment C3c and B were declining rapidly while C3 and C4 approached normal values first 36 days after treatment. An increase in heterophilic antibodies to sheep erythrocytes was observed after treatment with anti-venom globulin.

Adult↗
PubMed1978

Immune complexes in the sputum of patients with cystic fibrosis suffering from chronic Pseudomonas aeruginosa lung infection.

12 cystic fibrosis (CF) patients chronically infected with mucoid P. aeruginosa and presenting multiple precipitins in serum against this bacterium and 12 patients without P. aeruginosa infection were examined for occurrence of soluble immune complexes in their sputum sol phase by a complement consumption assay and a solid phase rheumatoid factor binding assay. The correlation between the results obtained in the two assays was significant (r = 0.625, p less than 0.01). The patients chronically infected with P. aeruginosa showed a significantly (p less than 0.01) higher frequency of immune complex activity in their sputum sol phase, as compared to the patients without P. aeruginosa lung infection. These findings point to the possibility that chronic lung infection with mucoid P. aeruginosa in CF may be an immune complex disease.

Adolescent↗
PubMed1978

Circulating immune complexes in ulcerative colitis.--II. Correlation with serum protein concentrations and complement conversion products.

Several serum proteins were quantified in twenty-two patients with active ulcerative colitis, and the findings were related to disease activity and occurrence of circulating immune complexes (IC). Conversion of C3 was significantly more frequent in the IC-positive group (eight patients) as compared to the IC-negative group (fourteen patients). Factor B was demonstrable in fifteen out of the twenty-two patients and seven out of the eight IC-positive patients had detectable levels of factor B. There was no difference between the IC-positive and the IC-negative group as regards serum concentrations of the complement factors C3, C4 and factor B, or serum orosomucoid, albumin, IgM and IgG. In contrast, the serum IgA levels tended to be reduced in the IC-positive group. C3 and factor B were significantly elevated in four patients with severe disease activity. In addition, C3, factor B and C4 concentrations showed a positive correlation to the serum orosomucoid levels. The serum concentrations of orosomucoid and albumin were inversely correlated to each other.

Adolescent↗
PubMed1977

Computed tomography in the diagnosis of cerebral abscess.

Computed tomography (CT) was performed 64 times on 22 patients with cerebral abcesses, using the 160 X 160 matrix EMI scanner. The diagnosis was based upon the demonstration of a localized low-attenuation area appearing, after the administration of contrast medium, as a high-attenuation annular rim ascribed to displaced and/or newly formed vessels, the so-called abscess membrane. CT is compared with the conventional diagnostic methods of neuroradiology. The differential diagnostic accuracy of CT is clearly superior to that of previous methods, including angiography, which, until now, we have considered the most accurate method.

Adolescent↗
PubMed1977

A survey for circulating immune complexes in patients with acute myocardial infarction. Use of a C1q-binding assay with soluble protein A as indicator.

A new assay for the detection of circulating C1q-binding immune complexes (IC) is described. The assay makes use of solid-phase C1q and iodinated soluble protein A, extracted from the cell wall of Staphylococcus aureus. In a model system the assay could detect heat-aggregated IgG down to a concentration of about 50 ng/ml. This method and three other assays, previously described, were used to survey the appearance of IC activity in sera from hospitalized patients with acute myocardial infarction. Depending on the assay system used, from 56% to 66% of the patients investigated were found to develop circulating IC. The earliest appearance of circulating IC was noted 5 days after infarction. The highest incidence of positive reactions and the strongest reactions occurred 2 to 3 weeks after hospitalization; thereafter the IC positiveness tapered off, and all patients were negative 6 weeks after infarction.

Acute Disease↗