PubMed Health⌕ Search

Biomedical subjects

H P Hansen

Publications and source records attributed to H P Hansen.

14 recordsLinked to original sources
PubMed1995

A zinc metalloproteinase is responsible for the release of CD30 on human tumor cell lines.

The activation marker CD30 is expressed on the cell surface of the malignant cells in Hodgkin's disease and a few non-Hodgkin lymphomas. We have analyzed the regulation of membrane-bound CD30 and found that the binding of a variety of anti-CD30 antibodies induced down-regulation of CD30 on cell lines. In addition, such down-modulation was also observed after treatment of the cell surface proteins with the sulfhydryl reagent iodoacetamide or after stimulation of the second messenger pathway with phorbol ester or calcium ionophore. This modulation was abolished at 4 degrees C and strongly inhibited by chelators like EDTA or 1,10-phenanthroline, whereas EGTA, a selective inhibitor of Ca(2+)-dependent proteinases and other inhibitors of serine, thiol and acid proteinases, showed no effect. The down-modulation was strengthened by Zn2+ or Cd2+, but not by other divalent cations such as Fe2+, Mn2+, Mg2+, Ca2+ or Co2+, thus indicating the involvement of a zinc metalloproteinase in CD30 modulation which can be activated by protein kinase C and by alkylation of sulfhydryl groups. Pulse-chase experiments, analysis of the CD30 glycosylation and specific measurement of the 90-kDa soluble form of CD30 (sCD30) with a sandwich radioimmunoassay revealed that CD30 down-modulation results from enhanced release of 90-kDa sCD30 by the site-specific cleavage of CD30 accomplished by a zinc metalloproteinase. This release occurs at the cell membrane without prior endocytosis.

Antibodies, Monoclonal↗
PubMed1995

Increased glomerular filtration rate after withdrawal of long-term antihypertensive treatment in diabetic nephropathy.

Initiation of antihypertensive treatment (AHT) in hypertensive insulin-dependent diabetic (IDDM) patients with diabetic nephropathy (DN) induces a faster initial (0 to 6 months) and a slower subsequent (6 months to end of observation) decline in GFR [delta GFR (ml/min/month) approximately 1.5 vs. 0.35]. Whether this initial phenomenon is reversible (hemodynamic) or irreversible (structural damage) after prolonged AHT is not known. To elucidate these mechanisms we investigated 42 hypertensive IDDM patients (16F/26M, age 40 +/- 7 years, mean +/- SD) with DN receiving AHT (angiotensin converting enzyme inhibition, N = 30) for 6 (2 to 15) years [median (range)]. GFR (ml/min/1.73 m2), arterial blood pressure (BP, mm Hg) and albuminuria (mg/24 hr) were measured the last day on AHT and one month after withdrawal of AHT. The measured variables were all significantly elevated after withdrawal of AHT: GFR [mean(SEM)] from 76(4) to 81(4) (P < 0.0001), BP [mean(SEM)] from 140/82 (2/1) to 151/89 (2/1) (P < 0.0005) and albuminuria [geometric mean (antilog SEM)] from 704 (1.2) to 1122 (1.2) (P < 0.0001). A correlation between relative rise in systolic blood pressure (delta Sys%) and relative change in GFR (delta GFR%) was found (r = 0.44, P < 0.005). Our results render some support of the hypothesis that the faster initial decline in GFR is due to a functional (hemodynamic) effect of AHT, which does not attenuate over time, while the subsequent slower decline reflects the beneficial effect on progression of diabetic nephropathy.

Adult↗
PubMed1989

[A dependent hierarchy--the relationship between qualitative and quantitative data from Anthony Wilden's "The Rules are no Game"].

This lecture is about the relationship between qualitative and quantitative data. The purpose is to show that quality and quantity are not opposites, the latter depends on the first. They are not of the same level of communication or reality. Quantity is a kind of quality, but quality is not a kind of quantity. To understand this dependent hierarchy it is necessary to withdraw the notion of context. Nature and culture also forms a dependent hierarchy, where complexity and diversity increase qualitatively from nature to culture. Context is most complex in culture, and for that reason it is often difficult to interpret the meaning of a statement. In life and society, meaning is a function of context.

Humans↗
PubMedDate not supplied

3D thin lead sheet compensating system.

The compensating filter system presented consists of a simulator mounted camera and light beam device. The light beam device produces a flash light beam 3-mm wide perpendicular to the x-ray axis. The distance between flashes can be varied from 0.5 to 2.5 cm in steps of 0.25 mm. An exposure of the patient in treatment position subject to a series of light flashes will produce a three-dimensional representation of the patient surface. This map is then properly enlarged. Lead sheets are cut and fixed to a Perspex plate which fits into a slot in the head of the accelerator. Regardless of energy, all compensators are made from 0.5-mm-thick lead sheets. To determine the proper distance between light flashes, measurements were performed in a water phantom for each x-ray energy to establish the equivalence of increasing numbers of layers of 0.5-mm lead. These measurements were compared to theoretical calculating using tissue maximum ratios, and finally checked against a wedged water phantom of 25 degrees as well as against a head and neck treatment field for the Alderson phantom. This way, a beam flattening of +/- 2% compared to the standard isodose lines was achieved.

Humans↗