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Biomedical subjects

P Bachmann

Publications and source records attributed to P Bachmann.

At least 73 records · Page 4Linked to original sources
PubMed1985

Immunofluorescence staining of thin-filament sections not participating in actomyosin crossbridges: studies by use of a monoclonal antibody specific to actin.

Monoclonal antibodies (mcab) were produced in vitro by fusing mouse X63-Ag8.653 plasmacytoma cells with spleen cells from a Balb/c mouse immunized with primary cultures of chick skeletal muscle (pmcc). After cloning on agar, stable clones were obtained, the antibodies of which stain specifically the I-band of myofibrils in the immunofluorescence (IF) procedure. For further characterization of these mcab their affinities to muscle proteins were tested by immunoblotting and by enzyme-linked immunosorbent assay (ELISA). Mcab specific for actin were revealed by these criteria. One of the anti-actin antibodies, mcab 647, reveals a variety of IF-staining patterns on myofibrils. On rest-length myofibrils the I-band is labeled only. However, at sarcomere lengths below 2 micrometers, where the thin filaments meet in the middle of the A-band and form a region of double overlap, an additional fluorescent band appears in this position. The fluorescence intensity of this band is increased significantly in shorter sarcomeres. Finally, when the I-band has disappeared at a sarcomere length of 1.5 micrometer, fluorescence is located exclusively in the middle of the A-band. These IF-staining patterns suggest that only those sections of the thin filament are stained that do not participate in actomyosin crossbridges.

Actins↗
PubMed1984

Persistence of Q strain of H2N2 influenza virus in avian species: antigenic, biological and genetic analysis of avian and human H2N2 viruses.

The characteristics of an avian influenza virus were compared in detail with those of human Asian (H2N2) influenza viruses. Antigenic analysis by different antisera against H2N2 viruses and monoclonal antibodies to both the hemagglutinin and neuraminidase antigens showed that an avian isolate, A/duck/München/9/79 contained hemagglutinin and neuraminidase subunits closely related to those of the early human H2N2 viruses which had been prevalent in 1957. However, this avian virus gave low HI titers with absorbed and non-absorbed antisera to different human H2N2 viruses isolated in 1957. Like human Q phase variant, such as A/RI/5-/57 (H2N2), hemagglutination of the above avian strain was not inhibited by the purified non-specific gamma-inhibitor from guinea pig serum. Growth behavior at restrictive temperature (42 degrees C) clearly differentiate the avian H2N2 virus from human influenza viruses, showing that the former virus grew well in MDCK cells at 42 degrees C but not the latters. Genomic analysis of these viruses revealed that the oligonucleotide map of H2N2 virus isolated from a duck was quite different from those of human H2N2 viruses from 1957 to 1967. The oligonucleotide mapping also indicated that different H2N2 influenza virus variants had co-circulated in humans in 1957.

Animals↗
PubMed1981

Stabilization of isometric DNA viruses against thermoinactivation by lowered ionic strength.

The thermostability of isometric DNA viruses increases, if the ionic strength is diminished before heating. When unpurified virus material from cell cultures is heated under conditions (temperature, time) which lead to a reduction in infectivity by 3 to 4 log10, this loss in titer is 1 to 3 log10 less, if the ionic strength is decreased by diluting the material in dist. water (1:100) before heating. A dilution in Eagle's MEM (1:100) or a previous dialysis against water does not have the same effect. This property was found in the following members of 4 DNA virus families: adenovirus 5, herpesvirus 1, SV 40 and bovine parvovirus 1. In contrast, members of pox- (vaccinia) and picornaviruses (polio 2, coxsackie B5) were found to be less thermostable under conditions of low ionic strength. Reovirus 3 showed no difference in inactivation. The observed effect may be of practical importance for heat disinfection of viruses and for their persistence in the environment.

Adenoviruses, Human↗
PubMed1980

Motility, linear arrangement and cell-to-cell contact of myogenic cells prior to fusion.

Time-lapse cinematography elucidates the genesis of a uniform and approximately linearly arranged myogenic cell aggregate, stemming from two larger cell groups. The ultimate aggregate is created by continuous movement of one cell group toward the other. Following this motion, the angle between the cell groups is reduced as they approach each other. Different patterns of cell motility can be recognized. Some cells move in a preferred direction in relation to the aggregate as a whole, whereas others alter their direction of movement. The myogenic cells are aligned end-to-end and side-by-side. The latter is often accomplished in the following manner: two cells in end-to-end contact form as crescent-shaped free space with their polar extensions; a neighboring spindle-shaped cell then settles in this space. An arrangement of cells such that their greatest cytoplasmic widths lie at the same level can also be seen. During the recording period, two cells in one of the groups were replicating. One of them realized karyo- and cytokinesis in approximately 80 min. The daughter cells moved apart in opposite directions, but never lost contact to the aggregate. This observation shows that contact between presumptive myoblasts and myoblasts is established.

Animals↗
PubMed1980

Semiautomated evaluation of morphometric data on myoblasts and myotubes and the calculation of the relative DNA content with the television texture analysis system (TAS).

In cell cultures of skeletal muscles from 11 day-old chick embryos, myoblasts begin to fuse to myotubes on the second day of culture. Morphological data such as area of projection of the nucleus, length of myotubes and number of nuclei per myotube, as well as histochemical data such as relative DNA content and degree of chromatin condensation were evaluated. The myotubes examined, up to 216 h in culture, had an average of 7 nuclei. These nuclei, which had ceased DNA synthesis prior to cell fusion had less dense chromatin than the nuclei of myoblasts. The data which represent DNA condensation support the concept that transcriptional activity is enhanced during de novo synthesis of muscle protein.

Animals↗
PubMed1980

The influence of preset integer intervals at the densitometer unit of the television texture analysis system (TAS) on DNA quantification.

The relative DNA content of Feulgen stained nuclei, or concentrations of stoichiometrically binding dyes can be determined by the television texture analysis system. This determination is based on the measurement of areas at preset integer intervals of transmittance. The method includes an unavoidable error in DNA quantification caused by the smallest preset integer value of transmittance at the densitometer unit. The error at the TAS is calculable by a theoretical reduction of the preset intervals for delta T. The calculation results in a correcting factor of 0 less than or equal to 4.1% of the whole measured area of a nucleus. The revised relative DNA content can now be calculated by D=E.A.1.041.

Cytological Techniques↗
PubMed1980

[Psychology, psychopathology and social problems of children with cystic fibrosis].

The authors examined 33 children aged 7 to 17 years who suffered from cystic fibrosis. This was possible in a holiday camp especially organized for such children. In two or more sessions different tests of performance and projection were made. Furthermore, case histories, the present physical state of the children, the observations of the nursing staff and the answers of the parents to a questionnaire were used as components of the examination. 27 children (88%) showed a moderate or severe psychoreactive disturbance directly related with the disease. There is a connection between the severity of the illness and the degree of the psychoreactive disturbance. 12 children (36%) showed a noticeable to severe psychoorganic disturbance of performance. All psychoorganically disturbed children suffered from a moderate or severe form of cystic fibrosis. 14 children (47%) suffered from further non specific psychoreactive disorders, partially with neurotic or psychosomatic symptoms which are without exception causally related to a disturbed social background. In any case, incidence and even severity of psychopathological findings in children with cystic fibrosis cannot be ignored and must be taken into consideration at the elaboration of a therapeutical plan. Holiday camps with full comprehensive care and control of the cystic fibrosis children are of great importance for them and their parents, especially with regard to the mental hygiene.

Adolescent↗
PubMed1979

Principles and methods for the quantitative determination of Feulegen stained DNA with the television texture analysis system (TAS).

The television texture analysis system (TAS, Leitz) has been applied to determination of the relative DNA content of Feulgen stained nuclei. The principles of the method are described and comparative measurements are presented. The determination is based on the measurement of areas at preset intervals of transmittance, taking into consideration the necessary correction of extinction values in relation to area and applying a correction for background. The data obtained can be used for the quantitative determination of DNA, and to provide analytical information for quantitation of structure. Comparison of the mean of extinctions as recorded with the scanning photometric method and those recorded with the television texture analysis method, with which 43 nuclei were investigated in transmittance steps of 0.01, revealed a coefficient of correlation of 0.9938.

Amnion↗
PubMed1979

"Blind focusing": an objective method for avoiding errors of focus at the television texture analysis system (TAS).

The amount of light energy a particle absorbs does not depend upon correct focus. The change in the path of light rays brought about by defocusing causes absorbing areas to be registered as areas of higher transmittance than when in focus. Already wellknown in photometry, this effect is put to use by the "blind focus" method at the television texture analysis system (TAS, Leitz). Some chromophores within the object to be measured are compared to a preset value of transmittance, for example T = 0.40. Only the area representing the structures as dense or denser than the preset density are registered. If the structures are out of focus the size of the registered area is too low, since by defocusing, structures to be measured become pale and diffuse, the correct focus corresponds to the largest area to a preset value of transmittance.

Amnion↗
PubMed1976

Importance of protease inhibition in studies on purified factor VIII (antihaemophilic factor).

According to some authors factor VIII procoagulant activity may be dissociable from carrier protein (MW approximately 2 X 10(6) by agarose gel filtration, e.g. at high ionic strength. We were able to reproduce this phenomenon. However, addition of protease inhibitor (Trasylol) prevented the appearance of low molecular weight peak of factor VIII procoagulant activity both at high ionic strength and elevated temperature (37 degrees C). We conclude from our results that procoagulant activity and carrier protein (von Willebrand factor, factor VIII antigen) are closely associated functional sites of native factor VIII macromolecule. Consequently, proteolytic degradation should be avoided in functional and structural studies on factor VIII and especially in preparing factor VIII concentrate for therapeutic use.

Antigens↗