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Biomedical subjects

B Nielsen

Publications and source records attributed to B Nielsen.

At least 253 records · Page 14Linked to original sources
PubMed1987

Does diet-induced thermogenesis change the preferred ambient temperature of humans?

The thermal scores of nude resting subjects were followed for a period of 5 h. the subjects were sitting at rest from 0700 until 1200 hours at their previously determined preferred ambient temperature. Whether fasting or with a large (3.700 kJ) meal their comfort score remained the same and constant throughout the experiment. Their comfort sensation was not influenced by a significant, 20%, increase in metabolic rate produced by the meal, nor by the gradual rise in body temperature due to the diurnal rhythm.

Adult↗
PubMed1987

A method for the blocking of endogenous immunoglobulin on frozen tissue sections in the screening of human hybridoma antibody in culture supernatants.

Endogenous immunoglobulin in tissue sections pose a problem in immuno-histochemical techniques employing homologous antibody as primary reagents and enzyme-labelled anti-immunoglobulin for the development. A method for the blocking of endogenous immunoglobulin in human tissue sections by incubation with monomeric pepsin fragments (Fab') of rabbit anti-human immunoglobulin before applying monoclonal antibody was evaluated for the screening of human monoclonal antibody. It was initially demonstrated that Fab' rabbit anti-human IgM and anti-IgG could block endogenous immunoglobulin in human IgM and IgG producing tumors thereby abolishing the binding of subsequently applied peroxidase-labelled anti-IgM or anti-IgG. Frozen sections of human colo-rectal adenocarcinomas show a variable background staining caused by the endogenous immunoglobulin. The background completely disappeared in the IgM system by preincubation with Fab' anti-IgM while the background was clearly reduced but not abolished in the IgG system. A human hybridoma supernatant containing IgM reactive with colo-rectal adenocarcinoma could easily be screened on frozen sections using this method. This approach should be generally useful for the screening of human antibody on human tissue sections.

Antibodies, Monoclonal↗
PubMed1987

Eosinophilia in hemodialysis patients.

Thirteen percent of 99 patients undergoing maintenance hemodialysis showed an increased predialysis peripheral blood eosinophil count (mean value of 828 cells/mm3, range 410-2,710). Patients with eosinophilia were predominantly male and evidenced more frequent elevation of total plasma IgE levels. Otherwise, no differences were found between patients with and without eosinophilia.

Adolescent↗
PubMed1987

Bactericidal effect of polymorphonuclear leukocytes on Pseudomonas aeruginosa pre-incubated in ofloxacin.

The in vitro effect of human polymorphonuclear leukocytes on sub-MIC-ofloxacin-treated Pseudomonas aeruginosa was studied. Two bacteria strains were selected: one serum-sensitive and one serum-resistant. Exposure of the bacteria to subinhibitory concentrations of ofloxacin caused the bacteria to elongate into filaments. Pseudomonas aeruginosa was incubated with polymorphonuclear leukocytes and the bactericidal effect was quantitated by the reduction of CFUs. The killing of untreated and ofloxacin-treated bacteria did not differ when normal human serum was used for opsonization. However, when heat-inactivated serum or buffer was used, the killing of ofloxacin-treated bacteria was increased from 40% to 63% (P less than 0.05). Kinetic studies showed that this effect increased with prolonged incubation time. In addition, polymorphonuclear leukocytes incubated with ofloxacin had an increased bactericidal activity, probably due to intracellular uptake of the drug. Phagocytic ingestion of the bacteria was not influenced by ofloxacin-treatment. These findings support other investigations with DNA-gyrase inhibitors, which show that exposed bacteria become more susceptible to killing and that antibiotic-treated polymorphonuclear leukocytes react more strongly.

Anti-Bacterial Agents↗
PubMed1987

Human-human hybridomas generated with lymphocytes from patients with colorectal cancer.

Human-human hybridoma technology was used to produce human monoclonal antibodies with reactivity to colorectal cancer antigens. Two different B-lymphoma cell lines were fused with lymphocytes obtained from mesenteric lymph nodes from colorectal cancer patients. The fusion frequency was 11% with LICR-LON-HMy-2. Out of 294 growing hybridomas 26 secreted antibodies reacting with epitopes on cultured colon adenocarcinoma cells. Only one (D4213) was established and has now been in culture for 1.5 years. D4213 antibody shows a strong reaction with colon cancer tissue compared with normal colon epithelium. Using W1-L2-729-HF2 the fusion frequency was about 50%. Of 2,487 hybridomas 499 produced immunoglobulin and 44 of these reacted with colon cancer tissues or cultured cancer cells. One of the established hybridomas produces antibody reacting with cancer cell membrane antigens, and on immunoblotting a number of components were stained. The antibody from the other hybridomas reacts with cytoplasmatic antigens, and only one of these showed reactivity in immunoblotting where it bound to a component with Mr of about 60K.

Antibodies, Monoclonal↗
PubMed1986

Human-human hybridomas for the study of anti-tumor immune response in patients with colorectal cancer.

Human-human hybridoma technology was evaluated for the study of humoral immune reactions of colorectal cancer patients against their own tumors. Six fusions were carried out with lymphocytes from mesenteric lymph nodes from patients with colorectal cancer, using the human B-lymphoma cell line LICR-LON-HMy-2 as fusion partner. A total of 294 wells with cell growth were obtained. Supernatants from 26 of these reacted in enzyme-linked immuno-sorbent assay (ELISA) with one or more colon cancer cell lines. Cells from only one of these wells (D 4213) could be cloned. The clone was shown to produce antibody which by immunocytochemical analysis reacted with a panel of colon cancer cell lines and melanoma cell lines but not with several other cancer cell lines or normal human leukocytes. By immunohistochemical analysis on formalin-fixed paraffin-embedded tissue this antibody reacted strongly with antigen expressed by autologous and allogeneic colorectal cancers. Faint staining could occasionally be observed on normal colon epithelium. D4213 is a hybrid cell line since it is tetraploid and produces kappa and lambda light chains as well as gamma and mu chains, whereas HMy-2 produces only kappa and gamma chains. The study produces only kappa and gamma chains. The study suggests that patients may possess B cells producing antibody reactive with their own malignant cells.

Adenocarcinoma↗
PubMed1986

Experimental electrical stimulation of the bladder using a new device.

Repeated bladder contractions were evoked during a six month period in three unanaesthetized female minipigs by using unipolar carbon fiber electrodes embedded in the bladder wall adjacent to the ureterovesical junction. In contrast to bipolar and direct bladder muscle stimulation unipolar electrodes at each ureterovesical junction evoked bladder pressure increase similar to those produced in previous investigations in dogs. Sacral nerve stimulation of S2 evoked bladder contraction at a minimal current. Microscopic examination revealed no cellular reactions to the carbon fibers but a subcutaneous reaction to the receivers was seen and was thought to be due to mechanical irritation. The clinical implication of the findings is discussed.

Animals↗
PubMed1986

Fluid balance in exercise dehydration and rehydration with different glucose-electrolyte drinks.

After exercise dehydration (3% of body weight) the restoration of water and electrolyte balance was followed in 6 male subjects. During a 2 h rest period after exercise, a drink of one of four solutions was given as 9 X 300 ml portions at 15 min intervals: control (C-drink), high potassium (K-drink), high sodium (Na-drink) or high sugar (S-drink). An exercise test (submaximal and supramaximal work) was performed before dehydration and after rehydration. Dehydration reduced plasma volume by 16%, a process reversed on resting even before fluid ingestion began, due to release of water accumulated in the muscles during exercise. After 2 h rehydration, plasma volume was above the initial resting value with all 4 drinks. The final plasma volumes after the Na-drink (+14%) and C-drink (+9%) were significantly higher than after the K- and S-drinks. The Na-drink favoured filling of the extracellular compartment, whereas the K- and S-drinks favoured intracellular rehydration. In spite of the higher than normal plasma volume after rehydration, mean heart rate during the submaximal test was 10 bpm higher after rest and rehydration than in the initial test, and was not different between the drinks. The amount of work which could be performed in the supramaximal test (105% VO2max) was 20% less after exercise dehydration and subsequent rest and rehydration than before. This reduction was similar for all drinks, and may be due to a decreased muscle glycogen content (70% of initial) at the time of the second test.

Adolescent↗
PubMed1986

Generalised use of contrast degradation and contrast improvement factors in diagnostic radiology. Application to vanishing contrast.

Although field area and object thickness are important parameters in comparisons of techniques for optimal reduction of scattered radiation to the image, they are in practice seldom varied. For this reason, we suggest that contrast degradation (CDF) and contrast improvement (CIF) factors be more frequently used and appropriately defined to make the dependence of CDF and CIF on field area (collimation) and object thickness (compression) explicit. Definitions are formulated and the results of experiments and Monte Carlo calculations (comprising effects of collimation, compression, air gap, antiscatter grid, detector thickness) cited to illustrate their usefulness. Currently used expressions for CIF (derived assuming monoenergetic radiation) lack a factor to account for the change in primary contrast caused by the antiscatter method when this affects the energy distribution of the transmitted primary photons (grids and compression) or the fractions of photon energy imparted to the detector (when comparing different detectors). Values of this factor are calculated for some cases. Also, the appropriate choice of physical quantity to be used in the formulae for CDF and CIF is discussed. The energy imparted to the detector is advocated since this is directly related to the detector signals forming the image on, e.g. the x-ray film.

Humans↗
PubMed1986

Contact dermatitis to semisynthetic penicillins in factory workers.

45 workers developed dermatitis after handling semi-synthetic penicillins in a factory. All reacted on patch test, but several agents had to be used. Only 7 reacted to benzyl penicillin. 1/3 reacted to only one allergen, while 2/3 reacted to several. The duration of exposure before symptoms was short, often less than 2 months. 19 had hay fever or asthma, and they developed their symptoms after a shorter exposure time. A survey for airborne antibiotics was performed.

Air Pollutants, Occupational↗
PubMed1986

The Lundia Pro 5 dialyzer, a polycarbonate membrane dialyzer.

Results of acute and long-term test runs of the Lundia Pro 5 dialyzer are presented. It is concluded that it has worked as an effective and safe dialyzer during the test period. Thoughts on future dialyzer tests are put forward for consideration.

Blood Pressure↗
PubMed1986

Temperature regulation; effects of sweat loss during prolonged exercise.

Prolonged exercise leads to thermal dehydration which interferes with circulatory as well as thermoregulatory functions, due to the reduction of the volume of the circulating blood and the increased osmolality of the body fluids. The effect of the reduced filling of the vascular system is counteracted by an increase in heart rate and a peripheral vasoconstriction. The resulting reduction in skin perfusion and heat transfer leads to a higher than normal core temperature during exercise. The sweating mechanism is inhibited by hyperosmolality. This, too, results in an extra rise in exercise temperature plateau.

Body Temperature Regulation↗