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Biomedical subjects

J Kristensen

Publications and source records attributed to J Kristensen.

At least 73 records · Page 4Linked to original sources
PubMed1987

Five years experience with treatment of lung cancer. The role of mediastinoscopy.

Over a five-year period, 304 patients with non small cell carcinoma of the lung were evaluated for pulmonary resection. The patients were divided into three groups: 1) 180 patients operated without preoperative mediastinoscopy based on a normal appearing mediastinum on plain chest x-ray; 2) 107 patients with resection of both lung tissue and mediastinal tissue due to localised positive mediastinoscopic findings; 3) 17 patients who were found inoperable either due to poor lung function or diffuse mediastinal seeding. In group 1, 24% were peroperatively found to be inoperable due to mediastinal involvement. The rest were resected and received no further therapy. In group 2, 84 patients were resected and postoperatively irradiated on the mediastinal area. The incidence of bronchopleural fistulae in group 1 was 0.7% and in group 2 16%, and the survival at any period was significantly poorer for group 2 than for group 1. We conclude that every patient with pulmonary infiltrates must be subjected to mediastinoscopy before thoracotomy and should be excluded from operative intervention in the presence of positive mediastinoscopic findings.

Adult↗
PubMed1986

Red pulp of the spleen in autoimmune haemolytic anaemia and hereditary spherocytosis: morphometric light and electron microscopy studies.

Morphometric light and electron microscopy studies on perfusion-fixed spleens from 6 patients with autoimmune haemolytic anaemia and 18 patients with hereditary spherocytosis showed increased relative (and absolute) volumes of red pulp and absolute volumes of pulp cords when compared to 10 controls and 16 patients with immune thrombocytopenia without haemolysis. The mean erythrocyte volume density of the red pulp and mean erythrocyte area were significantly increased, and more of the erythrocytes' profiles were closer to being circular than in the controls. The changes within the splenic red pulp were qualitatively identical in the 2 cases of haemolytic disease, being quantitatively more pronounced, however, in hereditary spherocytosis than in autoimmune haemolytic anaemia.

Adolescent↗
PubMed1986

Red pulp in splenomegaly syndrome: morphometric light and electron microscopy studies.

From a series of consecutively studied spleens, perfusion-fixed and investigated according to a standardized procedure allowing morphometric investigations at the light and electron microscopic levels, 33 spleens causing splenomegaly syndrome (12 lymphoproliferative diseases, 10 hairy cell leukaemia, 11 myeloproliferative diseases) were compared with data in controls and autoimmune haemolytic anaemia and hereditary spherocytosis from previous studies. In splenomegaly syndrome, especially in hairy cell leukaemia and myeloproliferative diseases, less so in lymphoproliferative diseases, there is a disproportionate increase in the volume of pulp cords in the red pulp. Values for erythrocyte volume density are of the same order as splenic erythrocyte concentration determined by scintigraphic kinetic methods. Cases with complicating immunohaemolysis show a rather high proportion of erythrocyte profiles with nearly spheric shape as in autoimmune haemolytic anaemia and hereditary spherocytosis.

Adult↗
PubMed1985

Splenic pulp, plasma cells and foamy histiocytes in immune thrombocytopenia: combined morphometric immunohistochemical and ultrastructural studies.

Spleens from 16 splenectomized patients with immune thrombocytopenia (ITP) were compared with 10 controls (accidental and incidental splenectomy, staging laparotomy). Fresh unfixed material was secured for smears and cryostat sections, and splenic tissue was fixed by perfusion for histomorphometric, immunohistochemical and ultrastructural examination. The volumes of white pulp, including germinal centres, red pulp, and trabeculae and vessels were estimated. The ratio plasma cells containing various Ig-classes/total nucleated cells and the ratio immature/mature plasma cells were determined and the occurrence and character of foamy cells examined. There were slightly increased absolute volumes of white pulp, red pulp and trabeculae + major vessels in ITP, but the differences were not statistically significant. There was a statistically significant raised number of IgG-, IgA- and IgM-containing plasma cells in the germinal centres in ITP. More IgG-containing cells seemed to be immature than in controls, but the difference was not statistically significant. Light microscopy showed foamy histiocytes in 7 of 16 cases, but electron microscopy showed them in all cases of ITP. Foamy histiocytes reacted with antithrombocyte serum.

Adolescent↗
PubMed1984

Lithium induced interstitial nephropathy associated with chronic renal failure. Reversibility and correlation between functional and structural changes.

We have previously shown that administration of lithium to rats in the first weeks after birth results in a severe interstitial nephropathy. The aim of the present work was to study the relationship between functional impairment and structural lesions and to evaluate whether the nephropathy regresses after withdrawal of lithium. Three groups of animals were studied: 16 weeks-old controls (group A), rats treated with lithium for 16 weeks (group B) and rats treated for 8 weeks followed by 8 weeks without lithium (group C). Plasma urea and renal concentrating ability were determined and one kidney fixed by vascular perfusion with glutaraldehyde for light microscope morphometry. The results show a significant reduction in renal function after lithium treatment. There was a highly significant reduction in proximal tubular length and a pronounced increase in interstitial volume due to severe fibrosis. The total mass of glomerular tufts was also reduced, but not when this parameter was divided by the body weight. Sclerotic glomeruli were not observed. The structural and functional lithium-induced lesions are independent of sex and irreversible, since they persist 8 weeks after withdrawal of lithium. It is proposed that lithium-induced interstitial fibrosis is followed by proximal tubular atrophy with a reduction in the amount of functioning proximal tubules. This leads to a decrease in proximal tubular reabsorption of sodium and a disturbance in the glomerulo-tubular balance resulting in a decrease in glomerular filtration rate.

Animals↗
PubMed1983

The effect of leukotrienes C4 and D4 on microcirculatory flow in humans.

By quantifying the flare response, leukotrienes LTC4 and LTD4 were shown to increase the microcirculatory flow in a sigmoidal dose-response relation over the dose-range of 6.25-800 pmol. LTD4 was found to be more potent than LTC4 after 5 min, but not after 15 min, as estimated by this method. Laser-Doppler flowmeter studies confirmed that LTD4 is a more potent vasodilator than LTC4.

Blood Flow Velocity↗
PubMed1982

The effect of leukotriene C4 and D4 on cutaneous blood flow in humans.

Using a laser-Doppler-flowmeter the microvascular response to LTC4 and LTD4 was measured. Intradermal injection of 1 microgram LTC4 and LTD4 caused an increase in the microvascular cutaneous bloodflow. The increase in flow was equal to that caused by histamine in equimolar amounts. Blocking the triple-response did not change the response. The values measured after injection of histamine and leucotrienes were about 10-15 times the values found in undisturbed skin and represents probably a maximally dilated vascular bed. Injection of the leucotrienes caused a slight sensation of pain.

Adult↗
PubMed1978

Renal handling of phenol red. III. Bidirectional transport.

1. The renal excretion of phenol red and other phenolsulphophthalein dyes (bromophenol blue and bromothymol blue) was studied in clearance experiments on anaesthetized rabbits. 2. Net tubular excretion of phenol red reached a maximal value of 8 mumole/min at a plasma concentration of ultrafiltrable dye of about 0.1 mM and was decreased at higher plasma concentrations. Decreases in net tubular excretion at high plasma concentrations were also obtained for bromophenol blue and bromothymol blue suggesting tubular reabsorption in addition to tubular secretion of the dye. Conclusive evidence for reabsorption was provided by administration of probenecid which caused a fall in the excretion of the dyes below that filtered by the glomeruli. 3. Tubular reabsorption of phenol red during probenecid administration appeared to be proportional to the glomerular load and was increased under experimental conditions leading to a decrease of urinary pH. Experiments involving efflux of phenol red from liposomes gave no evidence of a significant role of transmembrane passage by non-ionic diffusion. It is suggested that the pH dependence of the reabsorptive process is the result of preferential reabsorption of the acid as compared to the basic form of the indicator dye across a hydrophilic pathway in the transporting membranes. 4. Clearance ratio of phenol red to that of p-aminohippurate at low plasma concentrations was about 0.3. They low degree of extraction of phenol red from renal plasma is attributed both to tubular reabsorption and binding of the dye by plasma proteins.

Absorption↗
PubMedDate not supplied

Delivery of antisense oligonucleotides using HPMA polymer: synthesis of A thiol polymer and its conjugation to water-soluble molecules.

Here, we report the synthesis and characterization of an HPMA-based polymer for use as a carrier for the delivery of water soluble drugs. The polymer contains active-sulfhydryl groups for coupling of ligands through a disulfide linkage. The polymer can also be prepared containing pendant amino groups in addition to the active-sulfhydryl moiety. This allows the use of different chemistries to conjugate a variety of ligands to the polymer. We demonstrate that a sulfhydryl-terminated antisense oligonucleotide can be efficiently and rapidly conjugated to the polymer. The polymer-oligonucleotide conjugate is efficiently taken up by cultured cells.

Cells, Cultured↗