Cloning, sequencing and expression of a full-length rabbit fast skeletal troponin-C cDNA

A full-length cDNA coding for troponin-C isolated from an adult rabbit fast skeletal muscle library has been sequenced and expressed in an E. coli host. The amino acid sequence derived from the coding region agrees with the published protein sequence except that the first two residues are reversed. The expressed protein was found to be identical to purified rabbit skeletal troponin-C based on electrophoretic mobilities in polyacrylamide gels containing either SDS or urea, and on immunoblotting. These results establish that our troponin-C cDNA clone is suitable for site-directed mutagenesis studies on the structure and function of troponin-C.

[Correlation between selenium levels in the human body and lung cancer. II. Multi-statistical analysis of the correlation between selenium levels in the blood, hair, lung and lung cancer]

18 factors, including possible lung cancer-causing factors and body selenium (Se) levels, were analyzed by computer-based multiple stepwise regression and main component analysis. 1. The results indicated that Se levels in blood, hair and lung had correlation with lung cancer to some extent. 2. The correlation of blood and lung Se was the most significant one, the significance of which was only second to age and smoking habits. The standardized regression and factor load coefficients showed a negative correlation with blood Se level and a positive one with lung Se level, which corresponded with the results obtained by the single factor analysis.

Synaptonemal complex antigen location and conservation

The axial cores of chromosomes in the meiotic prophase nuclei of most sexually reproducing organisms play a pivotal role in the arrangement of chromatin, in the synapsis of homologous chromosomes, in the process of genetic recombination, and in the disjunction of chromosomes. We report an immunogold analysis of the axial cores and the synaptonemal complexes (SC) using two mouse monoclonal antibodies raised against isolated rat SCs. In Western blots of purified SCs, antibody II52F10 recognizes a 30- and a 33-kD peptide (Heyting, C., P. B. Moens, W. van Raamsdonk, A. J. J. Dietrich, A. C. G. Vink, and E. J. W. Redeker, 1987, Eur. J. Cell Biol., 43: 148-154). In spreads of rat spermatocyte nuclei it produces gold grains over the cores of autosomal and sex chromosomes. The cores label lightly during the chromosome pairing stage (zygotene) of early meiotic prophase and they become more intensely labeled when they are parallel aligned as the lateral elements of the SC during pachytene (55 grains/micron SC). Statistical analysis of electronically recorded gold grain positions shows that the two means of the bimodal gold grain distribution coincide with the centers of the lateral elements. At diplotene, when the cores separate, the antigen is still detected along the length of the core and the enlarged ends are heavily labeled. Shadow-cast SC preparations show that recombination nodules are not labeled. The continued presence suggests that the antigens serve a continuing function in the cores, such as chromatin binding, and/or structural integrity. Antibody III15B8, which does not recognize the 30- and 33-kD peptides, produces gold grains predominantly between the lateral elements. The grain distribution is bimodal with the mean of each peak just inside the pairing face of the lateral element. The antigen is present where and while the cores of the homologous chromosomes are paired. From the location and the timing, it is assumed that the antigen recognized by III15B8 functions in chromosome pairing at meiotic prophase. The two anti-rat SC antibodies label rat and mouse SCs but not rabbit or dog SCs. A positive control using human CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia) anti-centromere serum gives equivalent labeling of SC centromeres in the rat, mouse, rabbit, and dog. It is concluded that the SC antigens recognized by II52F10 and III15B8 are not widely conserved. The two antibodies do not bind to cellular or nuclear components of somatic cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of the spermicidal activity and acute toxicity of nonoxynol-9 and agent 741 [alkylphenoxy polyethoxy ethanol(10)]

A spermicidal agent called "741" is used in the People's Republic of China as a substitute for nonoxynol-9 in vaginal contraceptive preparations. The relative spermicidal activity of these two agents was evaluated using dog, rabbit, monkey and human semen. Acute LD50 determinations in mice were also performed. The spermicidal activity and acute toxicity of both agents were either identical or very similar in all species. Since agent 741 is less expensive than nonoxynol-9 to manufacture and equally as potent in vitro, it is an alternative spermicide for vaginal contraceptive formulations.

Homozygous familial hypercholesterolemic patients in China

Five homozygous patients with familial hypercholesterolemia (FH) are described. Their serum cholesterol levels were between 603 and 907 mg/dl, with an average of 714 mg/dl. The mean value of serum cholesterol levels of the obligate heterozygous parents was 270 mg/dl. In the patient group, 87% of the serum cholesterol was distributed in low density lipoprotein (LDL) and the mean LDL cholesterol level was about 8.4 times that in a control group. Phospholipids in HDL in the patient group were significantly lower than in the controls. Lipid assays of xanthoma tissues revealed that the major lipid was cholesterol and its esters. LDL receptor activity in fibroblasts from the homozygotes was markedly decreased. Two patients yielded less than 2% of normal receptor activity and were classified as receptor-negative. The other 3 revealed receptor activities greater than 2% but less than 25% of normal receptor activity and were classified as receptor-defective.