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C Hammerberg

Publications and source records attributed to C Hammerberg.

65 records · Page 4Linked to original sources
PubMed1984

Load on knee joint structures and muscular activity during lifting.

The load on the knee joints during lifting has been less studied than low back load. Healthy subjects lifted a 12.8-kg box from floor to table-level in three different ways; 1) with straight knees, 2) with bent knees and the box in front of the knees, and 3) with bent knees and the box between the knees. The loading moment of force about the bilateral knee axis was calculated by means of a computerized static sagittal plane model. Electromyography was recorded from quadriceps and ischiocrural muscles. The beginning of the flexed-knee lifts caused a flexing loading knee moment of about 50 Nm and a knee angle of 90 degrees. Straight-knee lifts gave all through the lift an extending loading moment. During the final phase of all lifts there was an extending loading knee moment of about 55 Nm and a knee angle of 0 degrees. The three lifts were compared and discussed from a biomechanical and ergonomical point of view.

Adult↗
PubMed1982

Detection of A t-complex antigen by secondary cell-mediated lymphocytotoxicity.

Because of the inconsistency in published results concerning the serological detection of cell surface antigens coded for by the t-complex, a cell-mediated lymphocytotoxicity (CML) assay, secondary CML, was used in a search for t-antigens. By sensitizing C3H.Ttf (C3H.Brachyury, tufted) with the congenic strain C3H.Ttf/tw18 splenic cells, a response against lipopolysaccharide (LPS) stimulated splenic cells from C3H.Ttf/tw18 mice is obtained. The locus coding for the antigen detected by this reaction lies to the left of tf on the murine seventeenth chromosome. The secondary CML response to this antigen is H-2 restricted and detects an antigen on all t-haplotypes tested: tw18, tw18tf, t12, t6, th2tf, and tw5.

Animals↗
PubMed1980

H-2 analyses of blastocyst-derived cell lines from mice bearing T and tw18 mutations.

T/T and tw18/tw18 blastocysts appear to survive in culture for periods of 3 weeks at frequencies equal to that of normal embryos. We have, therefore, undertaken to generate cell lines with a homozygous mutant genotype. We attempted to identify these cells by H-2 haplotype analysis. The results indicate that barring recombination, which would be expected to occur at a frequency of about 15%, 1 of 10 blastocyst-derived cell lines from a (+/tw18 x +/tw18) cross had a tw18/tw18 genotype and 1 of 4 lines from a (T/+ x T/+) cross had a T/T genotype. Unexpectedly, all of the remaining lines were heterozygous; no +/+ lines were observed. The putative homozygous mutant lines might be useful in attempts to characterize tw18-specific antigens.

Absorption↗
PubMed1976

Histocompatibility-2 system in wild mice. II. H-2 haplotypes of t-bearing mice.

As a first step in the study of the possible relationship between the T/t and H-2 complexes, the H-2 antigenic composition of the strains carrying factors t12, tw32, tw2, tw8, t1, t0, t6, tw1, tw71, tw73, tw12, tw5, tw75, and t38 was studied by using a battery of antisera containing antibodies against inbred-derived H-2 antigens. In addition, five t strains (t12, t6, tw5, tw1, and tw2) were selected for the production of antisera against the H-2 complexes carried by t chromosomes. Spleen, lymph node, and thymus cells from H-2b/t heterozygotes and tw2/tw2 homozygotes were injected into appropriate F1 hybrids between two inbred strains that carried the inbred-derived H-2 antigens of the donor. Four new H-2 antigens and one Ia antigen were uncovered and were assigned the symbols H-2.106 through H-2.109, and Ia.101, respectively. Three new H-2 haplotypes were also described, based upon the H-2 antigenic pattern of three t factors, t12, tw1, and tw5. These new haplotypes were given the symbols H-2t12, H-2tw1, and H-2tw5. When the t factors were grouped according to their H-2 haplotypes, their distribution, with certain exceptions, corresponded to the complementation groups. Thus, t chromosomes in the same complementation group carried similar, if not identical, H-2 haplotypes, despite the fact that these chromosomes were derived from widely separated geographic areas. Such an association between the t and H-2 complexes is most unusual in light of what is known of the polymorphism of H-2 haplotypes in wild mice populations. It suggests more than a casual relationship, at least at the population level, between the t and H-2 loci.

Animals↗
PubMed1976

Immunogenetic analysis of H-2 mutations. V. Serological analysis of mutations H-2da, H-2ra, and H-2ka1.

The H-2 and Ia antigenic composition of strain pairs B10.D2 (H-2d) and M504 (H-2da). A.CA (H-2f) and M506 (H-2fa), and CBA (H-2k) and M523 (H-2ka) was compared by testing their cells against a battery of oligospecific antisera, by performing absorption analysis, and by cross-immunization. The two strains of each pair are congenric and differ in taht the second strain of the pair carries a mutation that occurred in the H-2 haplotype of the first strain. The Ia composition of each mutant haplotype was found to be the same as that of the haplotype from which the mutant was derived. Several differences in the serologically detectable H-2 antigens were found. The H-2d and H-2da haplotypes were found to differ in that the latter lost at least one and gained another antigen. The affected antigens were demonstrated to be classic H-2 antigens controlled by the H-2D locus. The H-2t and H-2fa haplotypes were found to differ in that antigens 26, 37, and 39, controlled by the latter, bound their respective antibodies less firmly than those controlled by the former haplotype. Since all three antigens are coded for by the H-2K locus, since no change was found in the D-region controlled antigens, and since the H-2fa mutation maps in the K end, we conclude that most likely the mutation occurred in the K region. The H-2k and H-2ka haplotypes were found to differ in that the latter lost one antigen encoded by the H-2Kk allele. This mutation, therefore, must have occurred in the H-2K locus. The data tip the scale of evidence in favor of the interpretation that each of the H-2 mutations occurred in a single region, either K or D. No evidence for a second mutation within any of the other H-2 regions was found.

Animals↗
PubMed1975

Linkage disequilibrium between H-2 and t complexes in chromosome 17 of the mouse.

Mice with t factors belonging to the same complementation group carry similar, if not identical, H--2 haplotypes although these factors were derived from widely separated geographical areas. This association between t and H--2 complexes suggests more than a casual relationship between the two complexes, at least at the population level.

Animals↗