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Biomedical subjects

A Lange

Publications and source records attributed to A Lange.

At least 163 records · Page 9Linked to original sources
PubMed1986

Statistical analysis of a liquid phase radioimmunoassay for immune complex determination.

A computer program is presented which enables iterative determination of the weighted standard curve and the quality control parameters calculation for the liquid phase radioimmunoassay which employs binding of labelled C1q as a measure of the presence of immunological complexes in serum samples. 22 independently performed laboratory tests were evaluated with respect to the presence of relationship between the dose (standardized human IgG aggregates) and response (fraction of radiolabelled C1q bound). On 14 occasions the plotted curve was sigmoidal in shape, the rest of the curves did not reach lower or upper asymptote. When the logistic transformation of this data was used the dose-response curve was linear and could be plotted with the use of the least square method. This allows calculation of the two other parameters of the sigmoidal curve (slope and midpoint). The slope of the weighted regression line, intercept point with the axis of ordinates and correlation coefficient were determined by means of the least square method for weighted linear regression with repetitions. When the iterative procedure was completed, content of immunological complexes in sera was calculated. The program is written in Fortran for the ODRA 1300 computer series. The printout consist of three parts. First part contains the original data, parameters and information about the form of input data. The second part of the printout consist of the results, obtained from non-weighted and weighted regression lines and the plotted regression line. The third part of the printout contains the final results of immune complexes determination.

Antigen-Antibody Complex↗
PubMed1985

Electron spin resonance study of phospholipid membranes employing a comprehensive line-shape model.

The electron spin resonance spectra of the 1-myristoyl-2-[6-(4,4-dimethyloxazolidine-N-oxyl)myristoyl]-sn-glycero- 3-phosphocholine spin-label in highly oriented, fully hydrated bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine have been studied as a function of temperature and magnetic field orientation. The oriented spectra show clear indications of slow motional components (rotational correlation times greater than 3 ns) even in the fluid phase (T greater than 23 degrees C), indicating that motional narrowing theory is not applicable to the spectral analysis. The spectra have been simulated by a comprehensive line-shape model that incorporates trans-gauche isomerization in addition to restricted anisotropic motion of the lipid long molecular axis and that is valid in all motional regimes. In the gel (L beta') phase the spin-label chains are found to be tilted at 28 degrees with respect to the normal of the orienting plane. In the intermediate (P beta') phase there is a continuous distribution of tilt angles between 0 degrees and 25 degrees. In fluid (L alpha) phase there is no net tilt of the lipid chains. The chains rotate at an intermediate rate about their long axis in the fluid phase (tau R,parallel = 1.4-6.6 ns for T = 50-25 degrees C), but the reorientation of the chain axis is much slower (tau R, perpendicular= 13-61 ns for T = 50-25 degrees C), whereas trans-gauche isomerization (at the C-6 position) is rapid (tau J less than or equal to 0.2 ns). Below the chain melting transition both chain reorientation and chain rotation are at the ESR rigid limit (tau R greater than or equal to 100 ns), and trans-gauche isomerization is in the slow-motion regime (tau J = 3.7-9.5 ns for T = 22-2 degrees C). The chain order parameter increases continuously with decreasing temperature in the fluid phase (SZZ = 0.47-0.61 for T = 50-25 degrees C), increases abruptly on going below the chain melting transition, and then increases continuously in the intermediate phase (SZZ = 0.79-0.85 for T = 22-14 degrees C) to an approximately constant value in the gel phase (SZZ congruent to 0.86 for T = 10-2 degrees C).(ABSTRACT TRUNCATED AT 400 WORDS)

Cyclic N-Oxides↗
PubMed1985

[Development of lung tumors in Syrian hamsters with a mixed Mycoplasma pneumoniae and influenza virus infection].

The authors studied morphological alterations in the lungs of Syrian hamsters infected intranasally with Mycoplasma pneumoniae and influenza virus. The animals were first infected with M. pneumoniae and after 7 days with influenza A/PR8 virus. On days 1-3 after infection with influenza virus (days 8-11 following infection with M. pneumoniae) the animals showed the appearance of multiple foci of bronchiolar epithelium proliferation. At the later stages of experiment the size of the foci of proliferation increased. On days 14-21 after infection with influenza virus (days 21-28 of experiment) the animals developed lung tumors.

Animals↗
PubMed1985

Evaluation of immunity of sheep after splenectomy, splenic artery ligation and autotransplantation of splenic tissue.

The studies aiming at evaluation of immunity after splenectomy, splenic artery ligation, and autotransplantation of splenic tissue were performed in sheep. It was found that splenectomy alters both humoral and cellular immunity. The phagocytic activity of granulocytes, reduced level of IgG, drop in T and ARF cells as well as bone marrow stimulation were noted. In animals subjected to splenic artery ligation or autotransplantation of splenic tissue no significant differences in parameters studied were observed. These results correlated with histological examinations indicate that in the case of spleen trauma two important steps should be followed: the spleen, if possible, should be saved or a spleen saving procedure should be employed; in case of extensive trauma or if contraindications for spleen saving exist, autotransplantation of splenic tissue should be performed.

Animals↗
PubMed1984

Dissociation of responses measured by natural cytotoxicity and chemiluminescence.

Monocyte/macrophage-mediated cytotoxicity requires the generation of activated oxygen radicals, which can be measured by chemiluminescence (CL). To investigate whether natural killer (NK) cell activity required activated oxygen species, both cytotoxicity against K562 target cells and CL were measured in cell populations of human peripheral blood. The following results were obtained: (a) Peripheral blood mononuclear cells (MNC) showed NK activity and a response in CL, which could be induced by viable or paraformaldehyde-fixed K562 target cells as well as by latex particles. (b) Both T cells and non-T cells exhibited NK activity, but T cells gave no K562- or latex-induced CL responses. (c) Depletion of phagocytic cells from MNC abolished CL, but only marginally affected NK activity. (d) Reconstitution of phagocyte-depleted MNC with adherent cells revealed a superadditive enhanced CL response, but had no augmenting effect on NK activity. (e) Phagocyte-depleted cell populations, enriched for NK activity by density gradient centrifugation, did not respond in K562- and latex-induced CL. (f) MNC, highly enriched for NK activity by cell sorting with a cytofluorograf using the fluorescein isothiocyanate-labeled monoclonal antibody anti-Leu-11a, responded only with reduced CL, whereas the NK activity was enriched up to 45-fold. From these results it is concluded that NK cell-mediated cytolysis of K562 target cells and K562-induced CL are not functionally correlated, but represent properties of two distinct cell populations, namely NK cells and monocytes.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1984

Cell sizes and apposition of dental hard tissues in rats.

The daily apposition of the enamel and dentin and the sizes of ameloblasts and odontoblasts in the first upper molar of 2- to 9-day-old and of 12-day-old rats were examined by light microscopy of freeze-dried sections. The formation of enamel in the first molar started at the age of 2 days and was completed in most of the analyzed areas at the age of 9 days. On each day the enamel on the mesial sides of the cusps was about twice as thick as on the distal sides. The differences in thickness of dentin between the mesial and distal sides of the cusps were not as marked as was seen for the enamel. However, the rapid formation of dentin seemed to continue longer on the mesial sides than on the distal sides. The height of the ameloblasts and odontoblasts showed similar differences between the mesial and distal sides as was seen in the formation of enamel and dentin. In addition, these cells showed a gradual increase and decrease in height during the observation period, with a maximal height in the analyzed area at the age of 4-6 days.

Aging↗
PubMed1984

A comparison of bone length and bone weight with embryo weight in chondrodystrophic and normal Beltsville small white turkey embryos.

Chondrodystrophic and normal 24-day old embryos obtained from matings of known heterozygotes (Ch/ch) of the Beltsville Small White turkey stock were compared for bone lengths and for bone weights as a percent of embryo weights. Bone and embryo weights were less in the chondrodystrophic embryos, and the bone weights were reduced proportionally more than embryo weights. The lengths of the humeri and tibiotarsi were shorter in chondrodystrophic embryos, and the tibiotarsi were shortened more than the humeri.

Animals↗
PubMed1984

[Circulating immune complexes and NK activity in systemic lupus erythematosus].

NK-activity of normal mononuclear cells is inhibited in vitro by addition of immune complexes or aggregated IgG. We therefore studied 20 sera of patients with systemic lupus erythematosus in order to investigate whether there is any correlation between the presence of circulating immune complexes and suppression of NK-activity. A correlation was not found.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1983

Circulating immune complexes and antiglobulins (IgG and IgM) in asbestos-induced lung fibrosis.

Thirty-nine asbestos workers were examined with respect to the presence of IgG and IgM antiglobulins and circulating immune complexes. The overall incidence of raised levels of IgM antiglobulins and immune complexes was 63 and 28%, respectively. In the group positive for immune complexes, IgM antiglobulins were found more frequently than in those asbestos workers lacking immune complexes. However, all cases with the highest levels of IgM antiglobulins had normal or only slightly elevated levels of immune complexes. IgG antiglobulin levels were not elevated in asbestos workers. Asbestos workers with IgG antinuclear antibodies had the highest incidence of elevated levels of immune complexes.

Adult↗
PubMed1983

Presentation of benzo(a)pyrene to microsomal enzymes by asbestos fibers in the Salmonella/mammalian microsome mutagenicity test.

The potential effect of asbestos fibers on mutagenicity of benzo(a)pyrene was investigated by using the Ames test. Asbestos fibers without a coating of benzo(a)pyrene or benzo(a)pyrene when not dissolved in DMSO lacked any mutagenic effect in the Salmonella/mammalian microsome mutagenicity test. However, when benzo(a)pyrene was adsorbed onto asbestos, significant numbers of mutated bacteria were observed. This shows that asbestos fibers can serve a carrier role presenting benzo(a)pyrene to the enzymatic microsomal system, thus enhancing mutagenicity of this compound.

Adsorption↗
PubMed1983

[Staining behavior and applicability of spectrally pure Capriblue GN, Stella Blue, Oxonin and Punky Blue].

The staining properties of 4 spectral pure derivates of Phenoxazin--Capriblue GN, Stella Blue, Oxonin, and Punky Blue--were investigated using human and animal tissues. Punky Blue and Stella Blue are newly synthesized derivates. A simplified staining technique was developed based on conventional fixing and mounting methods of histological materials. Punky Blue is a particularly contrasting metachromatic nucleus stain, and produces at pH = 4 and a staining period of 5 min a differentiated cell picture, the colours of which are comparable to conventional stains. The Oxonin-stain produces good contrasts after 2 min. Capriblue GN is only limited use as one-component tissue stain, due of its low metachromatic characteristics and Stella Blue, on its own, does not provide sufficient contract. The influence of electrolytes and hydrogen ions on the staining mechanisms will be discussed. An increase of hydrogen ions is used to control the selective staining of amphoteric biopolymers. The possible binding mechanisms of stains used are discussed in the light of their staining properties.

Chemical Phenomena↗
PubMed1982

[Thin-layer chromatography of mycobacterial lipids and its importance for the differentiation and identification of mycobacteria].

Methodical prerequisites to the differentiation of mycobacteria using thin-layer chromatography of their lipids described. The results of the identification of 112 strains belonging to 22 different species of Runyon's groups II, and III and IV are presented indicating that the lipid analysis permits the subdivision of mycobacteria into more species than with usual culture and biochemical methods. The technique even permits to differentiate between serotypes. In M. fortuitum strains several characteristic lipid patterns can be clearly distinguished, supporting the old opinion that different species are collected in the M. fortuitum-complex: M. giae, M. perigrinum, M. fortuitum, M, minetti. Three distinct lipid patterns were found in the M. avium strains investigated corresponding to the serotypes 1, 2, and 3. Using lipid analysis with two solvent systems it was possible to differentiate between 13 serotypes of M. intracellulare. In this way 9 species of Runyon's groups II could be identified, too. The serotypes Lunning, Gause and scrofulaceum were found to have characteristic lipid patterns permitting their differentiation by the technique described. Lipid analysis by means of thin-layer chromatography has been demonstrated to be a reliable inexpensive method, very useful for the identification and classification of mycobacteria not only for routine procedures but also for taxonomical problems and epidemiological purposes.

Chromatography, Thin Layer↗
PubMed1981

Relationship between plasma, dentin and bone fluoride concentrations in rats following long-term fluoride administration.

A detailed knowledge of fluoride (F) pharmacokinetics is necessary if its pharmacologic and toxicologic effects are to be adequately understood. In the present study plasma F concentrations have been analysed using repeated blood samples taken from the ethmoidal sinus of rats given 25, 50, 100 and 150 p.p.m. F in drinking water ad libitum for 79 days. A close relationship between the F-concentration in the drinking water and plasma F concentrations was found. When the administration of F was stopped, a rapid decline in plasma F concentration was noted during 48 hrs in all groups. The plasma F concentrations in the 25 p.p.m. group returned to preexperimental levels but remained elevated in the other groups. The F concentrations of dentin and bone were determined and calculated on a dry fat free basis. The results show that there was a close relationship between plasma, bone and dentin concentrations.

Animals↗